WorldWideScience

Sample records for non-catalytic thermal evaporation

  1. Study of non-catalytic thermal decomposition of triglyceride at hydroprocessing condition

    International Nuclear Information System (INIS)

    Palanisamy, Shanmugam; Gevert, Borje S.

    2016-01-01

    Highlights: • Thermolysis of triglycerides occurs above 300 °C and cracking intensify above 350 °C. • Decomposition of carboxylic group observed, and β-H abstraction gives radical. • Product contains aldehyde, ketonic, saturated/unsaturated, cyclic, glycerol group. • Gasoline fraction contains lighter, cyclic and unsaturated hydrocarbons. • Residues contain ester, dimer and carboxylic groups. - Abstract: Non-catalytic thermal decomposition of triglyceride is studied between 300 and 410 °C at 0.1 and 5 MPa in the presence of H 2 or inert gas. This test is carried in tubular reactor filled with inert material (borosilicate glass pellet). The qualitative and analytical results showed that n-alkanes and alkenes with oxygenated olefins were primary products, consistent with thermal cracking to lighter hydrocarbons. The resulting outlet fuel gas obtained mainly from the radical reaction and had high concentration of CO, ethylene and methane. The decomposition forms a large number of radical compounds containing acids, aldehydes, ketones, aliphatic and aromatic hydrocarbon groups. Lighter fraction contains mostly naphthenic group, and heavy fraction contains straight chain paraffinic hydrocarbons. When H 2 partial pressure raised, the cracking of heavy fractions is low, and products contain low concentration of the lighter and gasoline fractions. Here, the thermal decomposition of triglyceride yields lighter fractions due to cracking, decarboxylation and decarbonylation.

  2. Non-thermal plasmas for non-catalytic and catalytic VOC abatement

    International Nuclear Information System (INIS)

    Vandenbroucke, Arne M.; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

    2011-01-01

    Highlights: → We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. → The underlying mechanisms of plasma-catalysis for VOC abatement are discussed. → Critical process parameters that determine the influent are discussed and compared. - Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma-catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma-catalytic processes. In both parts (plasma-alone systems and plasma-catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.

  3. Biochar as porous media for thermally-induced non-catalytic transesterification to synthesize fatty acid ethyl esters from coconut oil

    International Nuclear Information System (INIS)

    Jung, Jong-Min; Lee, Jechan; Choi, Dongho; Oh, Jeong-Ik; Lee, Sang-Ryong; Kim, Jae-Kon; Kwon, Eilhann E.

    2017-01-01

    Highlights: • Biodiesel production using renewable resources. • Thermally-induced non-catalytic transesterification. • Synthesis of fatty acid ethyl esters without conventional catalysts. • Using biochar as porous medium in the non-catalytic transesterification. - Abstract: This study put great emphasis on evaluating biochar as porous media for the thermally-induced non-catalytic transesterification reaction to synthesize fatty acid ethyl esters (FAEE) from coconut oil. Thermogravimetric analysis (TGA) of coconut oil experimentally justified that the bond dissociation of fatty acid from the backbone of triglycerides (TGs) could be achieved, which finding could be applied to the non-catalytic transesterification reaction. To use biochar as porous medium, the surficial morphology of maize residue biochar (MRB) was characterized, revealing that biochar possessed the wider pore size distribution ranging from meso- to macro-pores than SiO 2 . The highest yield of FAEE from non-catalytic transesterification of coconut oil in the presence of MRB was 87% at 380 °C. To further enhance the FAEE yield, further studies associated with the production of FAEE with biochar made from different biomasses and various pyrolytic conditions should be performed.

  4. Evaporators

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard

    1996-01-01

    Type of evaporators. Regulation. Thermal dimensioning. Determination of pressure loss and heat transfer coefficients.......Type of evaporators. Regulation. Thermal dimensioning. Determination of pressure loss and heat transfer coefficients....

  5. Non-catalytic recuperative reformer

    Science.gov (United States)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  6. Evaporation

    International Nuclear Information System (INIS)

    Delaney, B.T.; Turner, R.J.

    1989-01-01

    Evaporation has long been used as a unit operation in the manufacture of various products in the chemical-process industries. In addition, it is currently being used for the treatment of hazardous wastes such as radioactive liquids and sludges, metal-plating wastes, and other organic and inorganic wastes. Design choice is dependent on the liquid to be evaporated. The three most common types of evaporation equipment are the rising-film, falling-film, and forced-circulation evaporators. The first two rely on boiling heat transfer and the latter relies on flash vaporization. Heat exchangers, flash tanks, and ejectors are common auxiliary equipment items incorporated with evaporator bodies to complete an evaporator system. Properties of the liquid to be evaporated are critical in final selection of an appropriate evaporator system. Since operating costs are a significant factor in overall cost, heat-transfer characteristics and energy requirements are important considerations. Properties of liquids which are critical to the determination of final design include: heat capacity, heat of vaporization, density, thermal conductivity, boiling point rise, and heat-transfer coefficient. Evaporation is an expensive technology, both in terms of capital costs and operating costs. Additionally, mechanical evaporation produces a condensate and a bottoms stream, one or both of which may require further processing or disposal. 3 figs

  7. Particle evaporation spectra with inclusion of thermal shape fluctuations

    International Nuclear Information System (INIS)

    Moretto, L.G.; Bowman, D.R.

    1987-04-01

    The origin of the substantial sub-Coulomb component observed in proton and 4 He evaporation spectra at high excitation energy is attributed to the thermal excitation of shape degrees of freedom. A critique of the Hauser-Feshbach theory as used in evaporation codes is presented. A new formalism including the thermal excitation of collective modes as well as quantal penetration in the framework of a transition state approach is derived. 5 figs

  8. Decomposition of thermally unstable substances in film evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Matz, G

    1982-10-01

    It is widely known that film evaporators are considered to permit really gentle evaporation of heat-sensitive substances. Nevertheless, decomposition of such substance still occurs to an extent depending upon the design and operation of the evaporator. In the following a distinction is made between evaporators with films not generated mechanically, namely the long tube evaporator (lTE) or climbing film evaporator, the falling film evaporator (FFE) and the multiple phase helical tube (MPT) or helical coil evaporators (TFE). Figs 1 and 2 illustrate the mode of operation. A theory of the decomposition of thermally unstable substances in these evaporators is briefly outlined and compared with measurements. Such a theory cannot be developed without any experimental checks; on the other hand, meausrements urgently need a theoretical basis if only to establish what actually has to be measured. All experiments are made with a system of readily adjustable decomposability, namely with aqueous solutions of saccharose; the thermal inversion of this compound can be controlled by addition of various amounts or concentrations of hydrochloric acid. In the absence of any catalysis by hydrochloric acid, the decomposition rates within in the temperature interval studied (60-130/sup 0/C) are so low that the experiments would take much too long and determination of the concentration differences (generally by polarimetric methods) would be very complicated. Such slight effects would also be very unfavourable for comparison with theory. (orig.)

  9. Radiant non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.

    2017-10-31

    A radiant, non-catalytic recuperative reformer has a flue gas flow path for conducting hot exhaust gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is positioned adjacent to the flue gas flow path to permit heat transfer from the hot exhaust gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, a portion of the reforming mixture flow path is positioned outside of flue gas flow path for a relatively large residence time.

  10. Total evaporation in thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    Callis, E.L.; Cappis, J.H.

    1996-01-01

    Experiments were conducted to assess the effects of impurities on the total evaporation method for mass spectrometric measurement of the isotope ratio of uranium. Standard samples were spiked with Na, Ca, Fe, Zr and Ba. The results indicated that only Fe, and possible Na, displayed any interference, and then only at high concentrations. One problem limiting the accuracy of the method is the determination of the relative efficiency of the collectors in the multicollector system. 3 refs., 1 tab

  11. Spent-fuel pool thermal hydraulics: The evaporation question

    International Nuclear Information System (INIS)

    Yilmaz, T.P.; Lai, J.C.

    1996-01-01

    Many nuclear power plants are currently using dense fuel arrangements that increase the number of spent fuel elements stored in their spent-fuel pools (SFPs). The denser spent-fuel storage results in higher water temperatures, especially when certain event scenarios are analyzed. In some of these event scenarios, it is conservative to maximize the evaporation rate, while in other circumstances it is required to minimize the evaporation rates for conservatism. Evaporation is such a fundamental phenomenon that many branches of engineering developed various equations based on theory and experiments. The evaporation rates predicted by existing equations present a wide range of variation, especially at water temperatures >40 degrees C. Furthermore, a study on which equations provide the highest and lowest evaporation rates has not been done until now. This study explores the sensitivity of existing evaporation equations to various parameters and recommends the limiting evaporation equations for use in the solution of SFP thermal problems. Note that the results of this study may be applicable to a much wider range of applications from irrigation ponds, cooling lakes, and liquid-waste management to calculating adequate air exchange rate for swimming pools and health spas

  12. Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S., E-mail: kbooksh@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 (United States)

    2015-05-15

    Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

  13. YBCO coated conductors by reactive thermal co-evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Schmatz, U.; Hoffmann, Ch.; Bauer, M.; Metzger, R.; Berberich, P.; Kinder, H. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    2001-12-01

    Coated tape conductors of YBCO require a deposition process allowing to obtain a high volume growth rate in order to produce long lengths of tape in a reasonable amount of time. We present our tape coating system where 15 parallel loops of travelling tape of 1 cm width can be coated simultaneously by reactive thermal co-evaporation. For high critical current densities, in-plane alignment of the YBCO film is necessary. Inclined substrate deposition (ISD) is a technique that allows to deposit in-plane oriented buffer layers suitable for YBCO growth at high deposition rates. We present results obtained for YBCO films grown on MgO-ISD buffer layers deposited by e-gun evaporation onto metallic tape substrates. (orig.)

  14. Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

    Directory of Open Access Journals (Sweden)

    Swati Arora

    2017-01-01

    Full Text Available Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te and bismuth (Bi were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD and scanning electron microscopy (SEM to show granular growth.

  15. Spin current relaxation time in thermally evaporated pentacene films

    OpenAIRE

    Tani, Yasuo; Kondo, Takuya; Teki, Yoshio; Shikoh, Eiji

    2017-01-01

    The spin current relaxation time [tau] in thermally evaporated pentacene films was evaluated with the spin-pump-induced spin transport properties and the charge current transport properties in pentacene films. Under an assumption of a diffusive transport of the spin current in pentacene films, the zero-field mobility and the diffusion constant of holes in pentacene films were experimentally obtained to be ~8.0x10^-7 m^2/Vs and ~2.0x10^-8 m^2/s, respectively. Using those values and the previou...

  16. Effect of the thermal evaporation rate of Al cathodes on organic light emitting diodes

    International Nuclear Information System (INIS)

    Shin, Hee Young; Suh, Min Chul

    2014-01-01

    Graphical abstract: - Highlights: • The TOF-SIMS analysis to investigate cathode diffusion during evaporation process. • Performance change of OLEDs prepared with different evaporation rate of Al cathode. • Change of electron transport behavior during thermal evaporation process. - Abstract: The relationship between the thermal evaporation rate of Al cathodes and the device performance of organic light-emitting diodes (OLEDs) was investigated to clarify the source of leakage current. Time-of-flight secondary ion mass spectrometry was applied to identify the diffusion of Li and Al fragments into the underlying organic layer during the thermal evaporation process. We prepared various OLEDs by varying the evaporation rates of the Al cathode to investigate different device performance. Interestingly, the leakage current level decreased when the evaporation rate reached ∼25 Å/s. In contrast, the best efficiency and operational lifetime was obtained when the evaporation rate was 5 Å/s

  17. Thermal denitrification of evaporators concentrates in reactor with fluidized bed

    International Nuclear Information System (INIS)

    Brugnot, C.

    1993-11-01

    As part of the treatments of liquid wastes coming from the Marcoule reprocessing plant, the study of a thermal denitrification process for evaporator concentrates has been chosen by the CEA/CEN Cadarache: the fluidized-bed calcination. This work presents the study of a calcination pilot-plant for wastes with a very high sodium nitrate content. After a reactional analysis carried out in a thermobalance on samples which are representative of the fluidized-bed compounds, the perfecting of many of the plant parameters - such as the solution injection system - was carried out on a scale-model at first. Then, it was verified on the pilot-plant, and some experiments have been carried out. A mathematical model for the particle growth inside the fluidized-bed is proposed. (author). 179 refs., 65 figs., 23 tabs

  18. Ion assisted deposition of thermally evaporated Ag and Al films

    International Nuclear Information System (INIS)

    Hwangbo, C.K.; Lingg, L.J.; Lehan, J.P.; Macleod, H.A.; Makous, J.L.; Kim, S.Y.; University of Arizona, Physics Department, Tucson, Arizona 85721; Aju University, Physics Department, Suwon, Korea)

    1989-01-01

    Optical, electrical, and microstructural effects of Ar ion bombardment and Ar incorporation on thermally evaporated Ag and Al thin films are investigated. The results show that as the momentum supplied to the growing films by the bombarding ions per arriving metal atom increases, the refractive index at 632.8 nm increases and the extinction coefficient decreases, lattice spacing expands, grain size decreases, electrical resistivity increases, and trapped Ar increases slightly. In Ag films, stress reverses from tensile to compressive and in Al films compressive stress increases. In the Al films the change in optical constants can be explained by the variation in void volume. The reversal of stress from tensile to compressive in Ag films requires a threshold level of momentum. The increase in electrical resistivity is related to the decrease in grain size and increase in trapped Ar in both types of film. Many of these properties correlate well with the momentum transferred, suggesting that the momentum is an important physical parameter in describing the influence of ion beam on growing thin films and determining the characteristics of thin metal films prepared by ion assisted deposition

  19. Heavy metal evaporation kinetics in thermal waste treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Ch; Stucki, S; Schuler, A J [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    To investigate the evaporation kinetics of heavy metals, experiments were performed by conventional thermogravimetry and a new method using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The new method allows online measurements in time intervals that are typically below one minute. The evaporation of Cd, Cu, Pb, and Zn from synthetic mixtures and filter ashes from municipal solid waste incineration (MSWI) was of major interest. (author) 2 figs., 4 refs.

  20. Preparation by thermal evaporation under vacuum of thin nickel films without support

    International Nuclear Information System (INIS)

    Prugne, P.; Garin, P.; Lechauguette, G.

    1959-01-01

    This note deals with the preparation of nickel films without support by means of the technique described but using a new evaporation apparatus. In effect it was necessary, in order to obtain these nickel films, to modify the thermal evaporation conditions. An attempt to obtain a film without support after evaporation in a conventional apparatus led almost invariably to defeat. This appeared to be due to the high concentration of oxygen and of various vapors (diffusion pumps, degassing, etc.) present in the residual atmosphere of the conventional evaporation system. Reprint of a paper published in 'Le Vide, N. 74, March-April 1958, p. 82-83

  1. Specificity Switching Pathways in Thermal and Mass Evaporation of Multicomponent Hydrocarbon Droplets: A Mesoscopic Observation.

    Science.gov (United States)

    Nasiri, Rasoul; Luo, Kai H

    2017-07-10

    For well over one century, the Hertz-Knudsen equation has established the relationship between thermal - mass transfer coefficients through a liquid - vapour interface and evaporation rate. These coefficients, however, have been often separately estimated for one-component equilibrium systems and their simultaneous influences on evaporation rate of fuel droplets in multicomponent systems have yet to be investigated at the atomic level. Here we first apply atomistic simulation techniques and quantum/statistical mechanics methods to understand how thermal and mass evaporation effects are controlled kinetically/thermodynamically. We then present a new development of a hybrid method of quantum transition state theory/improved kinetic gas theory, for multicomponent hydrocarbon systems to investigate how concerted-distinct conformational changes of hydrocarbons at the interface affect the evaporation rate. The results of this work provide an important physical concept in fundamental understanding of atomistic pathways in topological interface transitions of chain molecules, resolving an open problem in kinetics of fuel droplets evaporation.

  2. Thermal management optimization of a thermoelectric-integrated methanol evaporator using a compact CFD modeling approach

    DEFF Research Database (Denmark)

    Xin, Gao; Chen, Min; Snyder, G. Jeffrey

    2013-01-01

    exchange structure. The structure transfers the fuel cell exhaust heat to the evaporation chamber to evaporate the methanol, where TE modules are installed in between to facilitate the heat regulation. In this work, firstly, a numerical study is conducted to determine the working currents and working modes......To better manage the magnitude and the direction of the heat flux in an exchanger-based methanol evaporator of a fuel cell system, thermoelectric (TE) modules can be deployed as TE heat flux regulators (TERs). The performance of the TE-integrated evaporator is strongly influenced by its heat......, and uses a different material property acquisition method based on module manufacturers’ datasheets. Secondly, a simulation study is carried out on the novel evaporator to minimize its thermal resistance and to assess the evaporator pressure drop. The factors studied include: type of the fins of the heat...

  3. Thermal analysis of a direct evaporative cooling system enhancement with desiccant dehumidification for vehicular air conditioning

    International Nuclear Information System (INIS)

    Alahmer, Ali

    2016-01-01

    Highlights: • Thermal analysis was conducted to design a desiccant evaporative cooling system for vehicular air conditioning. • EC is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter. • Drawbacks of evaporative cooler of increased weight and reduced COP. • A rotary desiccant dehumidifier with generation was combined with evaporative cooling to be more efficient. - Abstract: This manuscript analyzes the sub-systems of evaporative cooler (EC) combined with desiccant dehumidification and regeneration for automotive air conditioning purpose. The thermodynamic and psychometric analysis was conducted to design all evaporative cooling system components in terms of desiccant selection, regeneration process, compact heat exchanger and evaporative cooler. Moreover, the effect of the desiccant, heat exchanger and evaporative performances on the mass flow rate and water sprayed required for evaporative cooling system was investigated. The results show that the theoretical evaporative cooling design will achieve two main objectives: lower fuel consumption and less environmental pollutants. However, it has the two drawbacks in terms of increased weight and reduces the coefficient of performance (COP). The main remark is that evaporating cooling system is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter.

  4. Evaporation thermal anslysis of Swallow-tailed Axial-grooved Heat Pipe

    Science.gov (United States)

    Zhang, Renping

    2018-03-01

    A detailed mathematical model that describes evaporating characteristics through thin liquid film at the evaporator section of swallow-tailed axial-grooved heat pipe was developed. The numerical simulation results about thin film profile, liquid-vapour interface temperature, evaporating rate and heat flux at the evaporating thin film region were given by the current investigation and the effect of superheat on the liquid-vapour interface temperature, evaporating mass rate and heat flux was discussed. Meanwhile, thermal model of the meniscus region at the evaporating section was developed to calculate the rate of heat transfer. The ratio of the heat conduction in the evaporating thin liquid film region and total heat rate were also discussed. It is indicated that the thickness of thin liquid film rises in a nearly linear fashion. The disjoining pressure can be neglected with increasing the liquid film thickness, tends to be negligibly small. The heat transfer rate at the intrinsic meniscus cannot be compared with that of the evaporating liquid film region.

  5. Effect of evaporation section and condensation section length on thermal performance of flat plate heat pipe

    International Nuclear Information System (INIS)

    Wang Shuangfeng; Chen Jinjian; Hu Yanxin; Zhang Wei

    2011-01-01

    Flat plate heat pipes (FPHPs) are one of the available technologies to deal with the high density electronic cooling problem due to their high thermal conductivity, reliability, and low weight penalty. A series of experiments were performed to investigate the effect of evaporation and condensation length on thermal performance of flat plate heat pipes. In the experiments, the FPHP had heat transfer length of 255 mm and width of 25 mm, and pure water was used as the working fluid. The results show that comparing to vapor chamber, the FPHP could realize long-distance heat transfer; comparing to the traditional heat pipe, the FPHP has large area contact with heat sources; the thermal resistance decreased and the heat transfer limit increased with the increase of evaporation section length; the FPHP would dry out at a lower heating power with the increase of condensation section length, which indicated that the heat transfer limit decreased, but the evaporator temperature also decreased; when the condensation section length approached to evaporation section length, the FPHP had a better thermal performance. - Highlights: → A strip sintered FPHP is proposed and tested. → The total heat transfer length reaches 255 mm → The efficiency of heat transport reaches 94.4%. → When the condensation section length approached to evaporation section length, the FPHP has better overall performance.

  6. Thermal CFD study and improvement of table top fridge evaporator by virtual prototyping

    Directory of Open Access Journals (Sweden)

    Georgi Todorov

    2017-09-01

    Full Text Available The present paper aims to assess and to improve existing design of evaporators for household table top refrigeration appliances using Computational Fluid Dynamics (CFD. This category of refrigerators are compact and cheap solutions for domestic appliance. The requirement for low cost solution does not cancel necessity of high effectivity, usually referred as “energy class”. The evaporator is important component of refrigerator heat transport system and to its efficiency. Existing design of evaporator is improved in two directions – as shape of the serpentine and as cross section – constrained by overall cost limit. Two groups of thermal CFD analyses are performed over various design variants. Used virtual prototypes enable to view in detail heat transfer process and to reach an better solution in means of overall price/performance. This study shows the effect of serpentine geometry on evaporator performance as well as demonstrates the benefits of virtual prototyping when targeting optimization and improvement.

  7. Speciation of mercury in soils and sediments by thermal evaporation and cold vapor atomic absorption

    International Nuclear Information System (INIS)

    Bombach, G.; Bombach, K.; Klemm, W.

    1994-01-01

    Evaporation studies of mercury in several chemical compounds, soils, and sediments with a high content of organic matter indicate that a quantitative release is possible at temperatures as low as 400 C. The desorption behaviour from a gold column is not influenced. Only from samples with a thermal prehistory, such as brown coal ash, did mercury evaporate at higher temperatures. Qualitative conclusions can be derived about the content of metallic mercury as well as mercury associated with organic matter or sulfide. A comparison of the analytical results obtained by using the evaporation technique or by dissolving using a mixture of conc. HCl and HNO 3 shows good agreement; the advantages of the evaporation technique are obvious at very low mercury concentrations. (orig.)

  8. Quality control for total evaporation technique by surface/thermal ionization mass spectrometer

    International Nuclear Information System (INIS)

    Kato, Seikou; Inoue, Sinichi; Yamaguchi, Katsuyuki; Tsutaki, Yasuhiro

    2007-01-01

    For the measurement of uranium and plutonium isotopic composition, the surface/thermal ionization mass spectrometry is widely used at the both nuclear facilities and safeguards verification laboratories. The progress of instrument specification makes higher sensitivity. The total evaporation technique is one of the latest measurement techniques by using this progress, in which all of uranium or plutonium on the filament would be evaporated by increasing the filament current. The accuracy and precision of this technique is normally checked by using the certified isotope reference materials measurement. But the fluctuation of ion beam is very different by each filament, depending on the chemical form of evaporation. So, it should be considered how to check the measurement quality of unknown samples which has no certified values. This presentation is focused on the monitoring of ion yields and pattern of isotope ratio fluctuation to attain the traceability between reference material and unknown sample as quality control approach of total evaporation technique. (author)

  9. Film-Evaporation MEMS Tunable Array for Picosat Propulsion and Thermal Control

    Science.gov (United States)

    Alexeenko, Alina; Cardiff, Eric; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Film-Evaporation MEMS Tunable Array (FEMTA) concept for propulsion and thermal control of picosats exploits microscale surface tension effect in conjunction with temperature- dependent vapor pressure to realize compact, tunable and low-power thermal valving system. The FEMTA is intended to be a self-contained propulsion unit requiring only a low-voltage DC power source to operate. The microfabricated thermal valving and very-high-integration level enables fast high-capacity cooling and high-resolution, low-power micropropulsion for picosats that is superior to existing smallsat micropropulsion and thermal management alternatives.

  10. Thermally evaporated Ag nanoparticle films for plasmonic enhancement in organic solar cells: effects of particle geometry

    NARCIS (Netherlands)

    Haidari, G.; Hajimahmoodzadeh, M.; Fallah, H.R.; Peukert, A.; Chanaewa, A.; von Hauff, E.L.

    2015-01-01

    We report on the simple fabrication of Ag NP films via thermal evaporation and subsequent annealing. The NPs are formed on indium tin oxide electrodes, coated with PEDOT:PSS and implemented into PCPDTBT:PC70BM solar cells. Scanning electron microscopy and atomic force microscopy are used to

  11. Thermally Evaporated Iron (Oxide) on an Alumina Barrier Layer, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Madaan, Nitesh; Kanyal, Supriya S.; Jensen, David S.; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-06

    We report the XPS characterization of a thermally evaporated iron thin film (6 nm) deposited on an Si/SiO_2/Al_2O_3 substrate using Al Ka X-rays. An XPS survey spectrum, narrow Fe 2p scan, narrow O 1s, and valence band scan are shown.

  12. Effect of Air Gap Entrapped in Firefighter Protective Clothing on Thermal Resistance and Evaporative Resistance

    Directory of Open Access Journals (Sweden)

    He Hualing

    2018-03-01

    Full Text Available Heat and water vapor transfer behavior of thermal protective clothing is greatly influenced by the air gap entrapped in multilayer fabric system. In this study, a sweating hot plate method was used to investigate the effect of air gap position and size on thermal resistance and evaporative resistance of firefighter clothing under a range of ambient temperature and humidity. Results indicated that the presence of air gap in multilayer fabric system decreased heat and water vapor transfer abilities under normal wear. Moreover, the air gap position slightly influenced the thermal and evaporative performances of the firefighter clothing. In this study, the multilayer fabric system obtained the highest thermal resistance, when the air space was located at position B. Furthermore, the effect of ambient temperature on heat and water vapor transfer properties of the multilayer fabric system was also investigated in the presence of a specific air gap. It was indicated that ambient temperature did not influence the evaporative resistance of thermal protective clothing. A thermographic image was used to test the surface temperature of multilayer fabric system when an air gap was incorporated. These results suggested that a certain air gap entrapped in thermal protective clothing system could affect wear comfort.

  13. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    Energy Technology Data Exchange (ETDEWEB)

    University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

    2011-07-19

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

  14. Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Christine J. [Univ. of California, Berkeley, CA (United States); Liu, Chen-Lin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Harmon, Christopher W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Strasser, Daniel [Univ. of California, Berkeley, CA (United States); Golan, Amir [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kostko, Oleg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chambreau, Steven D. [Edwards Air Force Base, ERC Inc., CA (United States); Vaghjiani, Ghanshyam L. [Air Force Research Laboratory, Edwards Air Force Base, CA (United States); Leone, Stephen R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-04-20

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N–]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca–]), are generated by vaporizing ionic liquid submicrometer aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Also, hotoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~0.3 eV), attributed to reduced internal energy of the isolated ion pairs. Lastly, the method of ionic liquid submicrometer aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally “cooler” source of isolated intact ion pairs in the gas phase compared to effusive sources.

  15. Studies for determining thermal ion extraction potential for aluminium plasma generated by electron beam evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V Dileep; Barnwal, Tripti A; Mukherjee, Jaya; Gantayet, L M, E-mail: dileepv@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2010-02-01

    For effective evaporation of refractory metal, electron beam is found to be most suitable vapour generator source. Using electron beam, high throughput laser based purification processes are carried out. But due to highly concentrated electron beam, the vapour gets ionised and these ions lead to dilution of the pure product of laser based separation process. To estimate the concentration of these ions and extraction potential requirement to remove these ions from vapour stream, experiments have been conducted using aluminium as evaporant. The aluminium ingots were placed in water cooled copper crucible. Inserts were used to hold the evaporant, in order to attain higher number density in the vapour processing zone and also for confining the liquid metal. Parametric studies with beam power, number density and extraction potential were conducted. In this paper we discuss the trend of the generation of thermal ions and electrostatic field requirement for extraction.

  16. Measuring the thermal insulation and evaporative resistance of sleeping bags using a supine sweating fabric manikin

    International Nuclear Information System (INIS)

    Wu, Y S; Fan, Jintu

    2009-01-01

    For testing the thermal insulation of sleeping bags, standard test methods and procedures using heated manikins are provided in ASTM F1720-06 and EN 13537:2002. However, with regard to the evaporative resistance of sleeping bags, no instrument or test method has so far been established to give a direct measurement. In this paper, we report on a novel supine sweating fabric manikin system for directly measuring the evaporative resistance of sleeping bags. Eleven sleeping bags were tested using the manikin under the isothermal condition, namely, both the mean skin temperature of the manikin and that of the environment were controlled to be the same at 35 °C, with the wind speed and ambient relative humidity at 0.3 m s −1 and 50%, respectively. The results showed that the novel supine sweating fabric manikin is reproducible and accurate in directly measuring the evaporative resistance of sleeping bags, and the measured evaporative resistance can be combined with thermal insulation to calculate the moisture permeability index of sleeping bags

  17. Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation.

    Science.gov (United States)

    Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao

    2016-09-07

    The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

  18. Spectroscopic study of jet-cooled indole-3-carbinol by thermal evaporation

    International Nuclear Information System (INIS)

    Moon, Cheol Joo; Kim, Eun Bin; Min, Ahreum; Ahn, Ahreum; Seong, Yeon Guk; Choi, Myong Yong

    2016-01-01

    Cruciferous vegetables such as cabbage, kale, broccoli, and cauliflower have relatively high levels of indole-3-carbinol (I3C), which can be used as a possible cancer preventative agent particularly for breast, cervical, colorectal, and other hormone-related cancers. Thus, this naturally occurring substance, I3C, is now being used in dietary supplements. In conclusion, we have succeeded in obtaining the R2PI spectrum of a thermally unstable sample, I3C, by using a thermal buffer (herein, uracil) for the first time. Use of thermal evaporation method for thermally unstable biomolecules using thermal buffers will allow us to explore more gas phase spectroscopic studies for their intrinsic physiological properties in the near future

  19. Spectroscopic study of jet-cooled indole-3-carbinol by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Cheol Joo; Kim, Eun Bin; Min, Ahreum; Ahn, Ahreum; Seong, Yeon Guk; Choi, Myong Yong [Gyeongsang National University, Jinju (Korea, Republic of)

    2016-10-15

    Cruciferous vegetables such as cabbage, kale, broccoli, and cauliflower have relatively high levels of indole-3-carbinol (I3C), which can be used as a possible cancer preventative agent particularly for breast, cervical, colorectal, and other hormone-related cancers. Thus, this naturally occurring substance, I3C, is now being used in dietary supplements. In conclusion, we have succeeded in obtaining the R2PI spectrum of a thermally unstable sample, I3C, by using a thermal buffer (herein, uracil) for the first time. Use of thermal evaporation method for thermally unstable biomolecules using thermal buffers will allow us to explore more gas phase spectroscopic studies for their intrinsic physiological properties in the near future.

  20. Spin-pump-induced spin transport in a thermally evaporated pentacene film

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Yasuo; Shikoh, Eiji, E-mail: shikoh@elec.eng.osaka-cu.ac.jp [Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Teki, Yoshio [Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

    2015-12-14

    We report the spin-pump-induced spin transport properties of a pentacene film prepared by thermal evaporation. In a palladium(Pd)/pentacene/Ni{sub 80}Fe{sub 20} tri-layer sample, a pure spin-current is generated in the pentacene layer by the spin-pumping of Ni{sub 80}Fe{sub 20}, which is independent of the conductance mismatch problem in spin injection. The spin current is absorbed into the Pd layer, converted into a charge current with the inverse spin-Hall effect in Pd, and detected as an electromotive force. This is clear evidence for the pure spin current at room temperature in pentacene films prepared by thermal evaporation.

  1. Numerical Investigation of AdBlue Droplet Evaporation and Thermal Decomposition in the Context of NOx-SCR Using a Multi-Component Evaporation Model

    Directory of Open Access Journals (Sweden)

    Kaushal Nishad

    2018-01-01

    Full Text Available To cope with the progressive tightening of the emission regulations, gasoline and diesel engines will continuously require highly improved exhaust after-treatment systems. In the case of diesel engines, the selective catalytic reduction (SCR appears as one of the widely adopted technologies to reduce NOx (nitrogen oxides emissions. Thereby, with the help of available heat from exhaust gas, the injected urea–water solution (UWS turns inside the exhaust port immediately into gaseous ammonia (NH3 by evaporation of mixture and thermal decomposition of urea. The reaction and conversion efficiency mostly depend upon the evaporation and subsequent mixing of the NH3 into the exhaust gas, which in turn depends upon the engine loading conditions. Up to now, the aggregation of urea after evaporation of water and during the thermal decomposition of urea is not clearly understood. Hence, various scenarios for the urea depletion in the gaseous phase that can be envisaged have to be appraised under SCR operating conditions relying on an appropriate evaporation description. The objective of the present paper is therefore fourfold. First, a reliable multi-component evaporation model that includes a proper binary diffusion coefficient is developed for the first time in the Euler–Lagrangian CFD (computational fluid dynamics framework to account properly for the distinct evaporation regimes of adBlue droplets under various operating conditions. Second, this model is extended for thermal decomposition of urea in the gaseous phase, where, depending on how the heat of thermal decomposition of urea is provided, different scenarios are considered. Third, since the evaporation model at and around the droplet surface is based on a gas film approach, how the material properties are evaluated in the film influences the process results is reported, also for the first time. Finally, the impact of various ambient temperatures on the adBlue droplet depletion characteristics

  2. Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

    Directory of Open Access Journals (Sweden)

    Stefanović Predrag Lj.

    2003-01-01

    Full Text Available A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder, and (d to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency.

  3. Effect of solution processed and thermally evaporated interlayers on the performance of backgrated polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jayawardena, K.D.G.I.; Amarasinghe, K.M.P.; Nismy, N.A. [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom); Mills, C.A. [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom); Advanced Coatings Group, Surface Engineering Department, Tata Steel Research Development and Technology, Swinden Technology Centre, Rotherham, S60 3AR (United Kingdom); Silva, S.R.P., E-mail: s.silva@surrey.ac.uk [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2015-09-30

    Polymer solar cells are fast gaining momentum as a potential solution towards low cost sustainable energy generation. However, the performance of architectures is known to be limited by the thin film nature of the active layer which, although required due to low charge carrier mobilities, limits the optical coupling to the active layer. The formation of periodic backgratings has been proposed as a solution to this problem. Here, we investigate the effect of solution processed and thermally evaporated interlayers on the performance of backgrated polymer solar cells. Analysis of device performance under standard conditions indicates higher power conversion efficiencies with the incorporation of the evaporated interlayer (5.7%) over a sol–gel processed interlayer (4.9%). This is driven by a more conformal coating as evidenced through two orders of magnitude higher electron mobilities (10{sup −5} versus 10{sup −7} cm{sup 2} V{sup −1} s{sup −1}) as well as the balanced electron and hole transport observed for the former architecture. It is believed that these results will catalyse further development of such device engineering concepts for improved optical coupling in thin film photovoltaics. - Highlights: • Effect of interlayers on backgrated photovoltaic devices is tested. • Evaporated interlayers lead to better device performance. • Better charge extraction is observed for evaporated interlayers.

  4. EVAPORATIVE DROPLETS IN ONE-COMPONENT FLUIDS DRIVEN BY THERMAL GRADIENTS ON SOLID SUBSTRATES

    KAUST Repository

    Xu, Xinpeng; Qian, Tiezheng

    2013-01-01

    A continuum hydrodynamic model is presented for one-component liquid-gas flows on nonisothermal solid substrates. Numerical simulations are carried out for evaporative droplets moving on substrates with thermal gradients. For droplets in one-component fluids on heated/cooled substrates, the free liquid-gas interfaces are nearly isothermal. Consequently, a thermal singularity occurs at the contact line while the Marangoni effect due to interfacial temperature variation is suppressed. Through evaporation/condensation near the contact line, the thermal singularity makes the contact angle increase with the increasing substrate temperature. Due to this effect, droplets will move toward the cold end on substrates with thermal gradients. The droplet migration velocity is found to be proportional to the change of substrate temperature across the droplet. It follows that for two droplets of different sizes on a substrate with temperature gradient, the larger droplet moves faster and will catch up with the smaller droplet ahead. As soon as they touch, they coalesce rapidly into an even larger droplet that will move even faster. © 2013 World Scientific Publishing Company.

  5. EVAPORATIVE DROPLETS IN ONE-COMPONENT FLUIDS DRIVEN BY THERMAL GRADIENTS ON SOLID SUBSTRATES

    KAUST Repository

    Xu, Xinpeng

    2013-03-20

    A continuum hydrodynamic model is presented for one-component liquid-gas flows on nonisothermal solid substrates. Numerical simulations are carried out for evaporative droplets moving on substrates with thermal gradients. For droplets in one-component fluids on heated/cooled substrates, the free liquid-gas interfaces are nearly isothermal. Consequently, a thermal singularity occurs at the contact line while the Marangoni effect due to interfacial temperature variation is suppressed. Through evaporation/condensation near the contact line, the thermal singularity makes the contact angle increase with the increasing substrate temperature. Due to this effect, droplets will move toward the cold end on substrates with thermal gradients. The droplet migration velocity is found to be proportional to the change of substrate temperature across the droplet. It follows that for two droplets of different sizes on a substrate with temperature gradient, the larger droplet moves faster and will catch up with the smaller droplet ahead. As soon as they touch, they coalesce rapidly into an even larger droplet that will move even faster. © 2013 World Scientific Publishing Company.

  6. An evaporation-based model of thermal neutron induced ternary fission of plutonium

    International Nuclear Information System (INIS)

    Lestone, J.P.

    2008-01-01

    Ternary fission probabilities for thermal neutron induced fission of plutonium are analyzed within the framework of an evaporation-based model where the complexity of time-varying potentials, associated with the neck collapse, are included in a simplistic fashion. If the nuclear temperature at scission and the fission-neck-collapse time are assumed to be ~ 1.2 MeV and ~ 10 -22 s, respectively, then calculated relative probabilities of ternary-fission light-charged-particle emission follow the trends seen in the experimental data. The ability of this model to reproduce ternary fission probabilities spanning seven orders of magnitude for a wide range of light-particle charges and masses implies that ternary fission is caused by the coupling of an evaporation-like process with the rapid re-arrangement of the nuclear fluid following scission. (author)

  7. Effectiveness of indirect evaporative cooling and thermal mass in a hot arid climate

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Eduardo [Programa de Pos-Graduacao em Tecnologia/Programa de Pos-Graduacao em Engenharia Civil, Departamento de Construcao Civil, Universidade Tecnologica Federal do Parana - UTFPR, Av. Sete de Setembro, 3165. Curitiba PR, CEP. 80230-901 (Brazil); Gonzalez Cruz, Eduardo [Instituto de Investigaciones de la Facultad de Arquitectura y Diseno (IFAD), Universidad del Zulia, Nucleo Tecnico de LUZ, Av. Goajira (16) con Calle 67, Maracaibo, CP 4011-A-526 (Venezuela); Givoni, Baruch [Department of Architecture, School of Arts and Architecture, UCLA, Los Angeles CA, USA, and Ben Gurion University (Israel)

    2010-06-15

    In this paper, we compare results of a long-term temperature monitoring in a building with high thermal mass to indoor temperature predictions of a second building that uses an indirect evaporative cooling system as a means of passive cooling (Vivienda Bioclimatica Prototipo -VBP-1), for the climatic conditions of Sde Boqer, Negev region of Israel (local latitude 30 52'N, longitude 34 46'E, approximately 480 m above sea level). The high-mass building was monitored from January through September 2006 and belongs to a student dormitory complex located at the Sde Boqer Campus of Ben-Gurion University. VBP-1 was designed and built in Maracaibo, Venezuela (latitude 10 34'N, longitude 71 44'W, elevation 66 m above sea level) and had its indoor air temperatures, below and above a shaded roof pond, as well as the pond temperature monitored from February to September 2006. Formulas were developed for the VBP-1, based on part of the whole monitoring period, which represent the measured daily indoor maximum, average and minimum temperatures. The formulas were then validated against measurements taken independently in different time periods. The developed formulas were here used for estimating the building's thermal and energy performance at the climate of Sde Boqer, allowing a comparison of two different strategies: indirect evaporative cooling and the use of thermal mass. (author)

  8. Fabrication of thermally evaporated Al thin film on cylindrical PET monofilament for wearable computing devices

    Science.gov (United States)

    Liu, Yang; Kim, Eunju; Han, Jeong In

    2016-01-01

    During the initial development of wearable computing devices, the conductive fibers of Al thin film on cylindrical PET monofilament were fabricated by thermal evaporation. Their electrical current-voltage characteristics curves were excellent for incorporation into wearable devices such as fiber-based cylindrical capacitors or thin film transistors. Their surfaces were modified by UV exposure and dip coating of acryl or PVP to investigate the surface effect. The conductive fiber with PVP coating showed the best conductivities because the rough surface of the PET substrate transformed into a smooth surface. The conductivities of PET fiber with and without PVP were 6.81 × 103 Ω-1cm-1 and 5.62 × 103 Ω-1cm-1, respectively. In order to understand the deposition process of Al thin film on cylindrical PET, Al thin film on PET fiber was studied using SEM (Scanning Electron Microscope), conductivities and thickness measurements. Hillocks on the surface of conductive PET fibers were observed and investigated by AFM on the surface. Hillocks were formed and grown during Al thermal evaporation because of severe compressive strain and plastic deformation induced by large differences in thermal expansion between PET substrate and Al thin film. From the analysis of hillock size distribution, it turns out that hillocks grew not transversely but longitudinally. [Figure not available: see fulltext.

  9. Growth and structure of thermally evaporated Bi{sub 2}Te{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rogacheva, E.I., E-mail: rogacheva@kpi.kharkov.ua [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Budnik, A.V. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Dobrotvorskaya, M.V.; Fedorov, A.G.; Krivonogov, S.I.; Mateychenko, P.V. [Institute for Single Crystals of NAS of Ukraine, 60 Lenin Prospect, Kharkov 61001 (Ukraine); Nashchekina, O.N.; Sipatov, A.Yu. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine)

    2016-08-01

    The growth mechanism, microstructure, and crystal structure of the polycrystalline n-Bi{sub 2}Te{sub 3} thin films with thicknesses d = 15–350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi{sub 2}Te{sub 3}. It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d. The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5–2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n-Bi{sub 2}Te{sub 3} thin films of a sufficiently high quality. - Highlights: • The polycrystalline n-Bi{sub 2}Te{sub 3} thin films were grown thermal evaporation onto glass. • The growth mechanism and film structure were studied by different structure methods. • The grain size and film roughness increased with increasing film thickness. • The growth direction changes from [00l] to [015] under film thickness increasing. • The oxidized layer thickness (1–2 nm) did not change under aging at room temperature.

  10. Thermal characteristics of a medium-level concentration photovoltaic unit with evaporation cooling

    Science.gov (United States)

    Kokotov, Yuri V.; Reyz, Michael A.; Fisher, Yossi

    2009-08-01

    The results of thermal analysis and experiments are presented for a 1-kW brand new medium-level (8X) concentration photovoltaic (CPV) unit that is cooled by evaporation and built as an elongated floating solar unit. The unit keeps the silicon PV elements at low and stable temperature around the clock, significantly outperforms competitors' systems in terms of the power output and the life span of identical PV elements. It is demonstrated theoretically and experimentally that the PV element temperature level exceeds the temperature level of water in the water basin (used as a heat sink) by just a few degrees.

  11. Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, Sean; Longcope, Dana [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2014-09-01

    Magnetic reconnection in the corona results in contracting flare loops, releasing energy into plasma heating and shocks. The hydrodynamic shocks produced in this manner drive thermal conduction fronts (TCFs) which transport energy into the chromosphere and drive upflows (evaporation) and downflows (condensation) in the cooler, denser footpoint plasma. Observations have revealed that certain properties of the transition point between evaporation and condensation (the 'flow reversal point' or FRP), such as temperature and velocity-temperature derivative at the FRP, vary between different flares. These properties may provide a diagnostic tool to determine parameters of the coronal energy release mechanism and the loop atmosphere. In this study, we develop a one-dimensional hydrodynamical flare loop model with a simplified three-region atmosphere (chromosphere/transition region/corona), with TCFs initiated by shocks introduced in the corona. We investigate the effect of two different flare loop parameters (post-shock temperature and transition region temperature ratio) on the FRP properties. We find that both of the evaporation characteristics have scaling-law relationships to the varied flare parameters, and we report the scaling exponents for our model. This provides a means of using spectroscopic observations of the chromosphere as quantitative diagnostics of flare energy release in the corona.

  12. Nondegradative Dielectric Coating of Graphene using Thermal Evaporation of SiO

    Science.gov (United States)

    Suzuki, Seiya; Lee, Chien-Chung; Nagamori, Takashi; Schibli, Thomas; Yoshimura, Masamichi

    2013-03-01

    Deposition of dielectrics onto graphene is a challenging technique due to the difficulties of fabricating high quality oxide on pristine graphene without introducing atomic defects. Here we report on a novel method to fabricate silicon oxide layer on graphene by vacuum thermal evaporation of silicon monoxide (SiO). Raman spectroscopy and mapping showed the present method did not degrade graphene, in contrast to the e-beam evaporated SiO2 coating method previously reported. We fabricated graphene field effect transistor devices with four metal electrodes to measure gate voltage dependence of sheet resistance of the graphene, and deposited a top coating of SiO on the graphene channel. The electrical measurements before and after the top-coating revealed that the top coating suppressed chemical shift of the graphene from strong p-dope to nearly undoped. Since SiO is transparent for visible and infrared light, the coating can be available as a protection layer for optical devices of graphene such as photodetectors and electro-optic modulators. Since the SiO top coating is a simple vacuum evaporation, it is much easier than atomic-layer-deposition which requires additional functionalization of graphene, and compatible with industrial use. This research was supported in part by Toyoaki Scholarship Foundation

  13. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and a significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  14. High-quality GaN nanowires grown on Si and porous silicon by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Shekari, L., E-mail: lsg09_phy089@student.usm.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Ramizy, A.; Omar, K.; Hassan, H. Abu; Hassan, Z. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer A new kind of substrate (porous silicon) was used. Black-Right-Pointing-Pointer Also this research introduces an easy and safe method to grow high quality GaN NWs. Black-Right-Pointing-Pointer This is a new growth process to decrease the cost, complexity of growth of GaN NWs. Black-Right-Pointing-Pointer It is a controllable method to synthesize GaN NWs by thermal evaporation. - Abstract: Nanowires (NWs) of GaN thin films were prepared on as-grown Si (1 1 1) and porous silicon (PS) substrates using thermal evaporation method. The film growth produced high-quality wurtzite GaN NWs. The size, morphology, and nanostructures of the crystals were investigated through scanning electron microscopy, high-resolution X-ray diffraction and photoluminescence spectroscopy. The NWs grown on porous silicon were thinner, longer and denser compared with those on as-grown Si. The energy band gap of the NWs grown on PS was larger than that of NWs on as-grown Si. This is due to the greater quantum confinement effects of the crystalline structure of the NWs grown on PS.

  15. Tungsten oxide thin films grown by thermal evaporation with high resistance to leaching

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Diogo S. [Universidade Federal de Pelotas (UFPel), RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos; Pazinato, Julia C.O.; Freitas, Mauricio A. de; Radtke, Claudio; Garcia, Irene T.S., E-mail: irene@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Quimica; Dorneles, Lucio S. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas

    2014-05-15

    Tungsten oxides show different stoichiometries, crystal lattices and morphologies. These characteristics are important mainly when they are used as photocatalysts. In this work tungsten oxide thin films were obtained by thermal evaporation on (100) silicon substrates covered with gold and heated at 350 and 600 °C, with different deposition times. The stoichiometry of the films, morphology, crystal structure and resistance to leaching were characterized through X-ray photoelectron spectroscopy, micro-Raman spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, Rutherford backscattering spectrometry and O{sup 16} (α,α')O{sup 16} resonant nuclear reaction. Films obtained at higher temperatures show well-defined spherical nanometric structure; they are composed of WO{sub 3.1} and the presence of hydrated tungsten oxide was also observed. The major crystal structure observed is the hexagonal. Thin films obtained through thermal evaporation present resistance to leaching in aqueous media and excellent performance as photocatalysts, evaluated through the degradation of the methyl orange dye. (author)

  16. Effect of magnetic field on the growth of Be films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Li, Kai; Luo, Bing-chi; Tan, Xiu-lan; Zhang, Ji-qiang; Wu, Wei-dong; Liu, Ying

    2014-01-01

    Highlights: • The Be films were prepared on Si (1 0 0) substrates with and without a magnetic field by thermal evaporation, respectively. • The grain diameter in the Be film transited from 300 nm to 18 nm by application of the magnetic field. • The surface roughness of the Be film decreased from 61 nm to 3 nm by application of the magnetic field. • The Be film grown with the magnetic field was easily oxidized due to its refined grains and the oxidation was gradually decreased with increasing the etching depth in the film. - Abstract: Grain refinement of beryllium deposits is studied as a significant subject for beryllium capsule in the Inertial Confinement Fusion project. The Be films were prepared on the Si (1 0 0) substrates by thermal evaporation with and without a magnetic field, respectively. The two separate groups of prepared Be films were characterized. The results showed the grain diameter in the Be film transited from 300 nm to 18 nm and the surface roughness of the Be film decreased from 61 nm to 3 nm by application of the magnetic field during the deposition process of Be coating. However, the Be film grown with the magnetic field was easily oxidized in comparison with that grown without magnetic field due to the refined grains, and the oxidation was gradually decreased with the increase of etching depth in the Be film. The reason for grain refinement of Be film was also qualitatively described

  17. Molecular dynamics simulations for the motion of evaporative droplets driven by thermal gradients along nanochannels

    KAUST Repository

    Wu, Congmin

    2013-04-04

    For a one-component fluid on a solid substrate, a thermal singularity may occur at the contact line where the liquid-vapor interface intersects the solid surface. Physically, the liquid-vapor interface is almost isothermal at the liquid-vapor coexistence temperature in one-component fluids while the solid surface is almost isothermal for solids of high thermal conductivity. Therefore, a temperature discontinuity is formed if the two isothermal interfaces are of different temperatures and intersect at the contact line. This leads to the so-called thermal singularity. The localized hydrodynamics involving evaporation/condensation near the contact line leads to a contact angle depending on the underlying substrate temperature. This dependence has been shown to lead to the motion of liquid droplets on solid substrates with thermal gradients (Xu and Qian 2012 Phys. Rev. E 85 061603). In the present work, we carry out molecular dynamics (MD) simulations as numerical experiments to further confirm the predictions made from our previous continuum hydrodynamic modeling and simulations, which are actually semi-quantitatively accurate down to the small length scales in the problem. Using MD simulations, we investigate the motion of evaporative droplets in one-component Lennard-Jones fluids confined in nanochannels with thermal gradients. The droplet is found to migrate in the direction of decreasing temperature of solid walls, with a migration velocity linearly proportional to the temperature gradient. This agrees with the prediction of our continuum model. We then measure the effect of droplet size on the droplet motion. It is found that the droplet mobility is inversely proportional to a dimensionless coefficient associated with the total rate of dissipation due to droplet movement. Our results show that this coefficient is of order unity and increases with the droplet size for the small droplets (∼10 nm) simulated in the present work. These findings are in semi

  18. Characterization of thermally evaporated lead iodide films aimed for the detection of X-rays

    International Nuclear Information System (INIS)

    Caldeira Filho, A.M.; Mulato, M.

    2011-01-01

    Some semiconductor materials such as lead iodide (PbI 2 ) have applications in the detection of ionizing radiation at room temperature using the direct detection method. In this work we investigate lead iodide films deposited by thermal evaporation. The morphology, structure, and electric properties were investigated as a function of deposition height, i.e. the distance between evaporation-boat and substrates. The results show a morphology of vertical leaves and X-ray diffraction shows just one preferential orientation along the direction 110. Energy dispersive spectroscopy reveals that the films are not stoichiometric, with excess iodine atoms. Electrical resistivity of about 10 8 Ω cm was measured. This is smaller than for the bulk due to structural defects. The values of activation energy for electric transport increase from 0.52 up to 1.1 eV with decreasing deposition height, what indicates that the best film is the one deposited at the shortest distance. Exposure under X-ray mammographic energy shows a linear behavior up to 500 mR. No variation in sensibility was observed between 22 and 30 kVp.

  19. CO{sub 2} evaporative cooling: The future for tracking detector thermal management

    Energy Technology Data Exchange (ETDEWEB)

    Tropea, P., E-mail: paola.tropea@cern.ch [CERN, Geneva (Switzerland); Daguin, J.; Petagna, P.; Postema, H. [CERN, Geneva (Switzerland); Verlaat, B. [CERN, Geneva (Switzerland); Nikhef, Amsterdam (Netherlands); Zwalinski, L. [CERN, Geneva (Switzerland)

    2016-07-11

    In the last few years, CO{sub 2} evaporative cooling has been one of the favourite technologies chosen for the thermal management of tracking detectors at LHC. ATLAS Insertable B-Layer and CMS Pixel phase 1 upgrade have adopted it and their systems are now operational or under commissioning. The CERN PH-DT team is now merging the lessons learnt on these two systems in order to prepare the design and construction of the cooling systems for the new Upstream Tracker and the Velo upgrade in LHCb, due by 2018. Meanwhile, the preliminary design of the ATLAS and CMS full tracker upgrades is started, and both concepts heavily rely on CO{sub 2} evaporative cooling. This paper highlights the performances of the systems now in operation and the challenges to overcome in order to scale them up to the requirements of the future generations of trackers. In particular, it focuses on the conceptual design of a new cooling system suited for the large phase 2 upgrade programmes, which will be validated with the construction of a common prototype in the next years.

  20. CO_2 evaporative cooling: The future for tracking detector thermal management

    International Nuclear Information System (INIS)

    Tropea, P.; Daguin, J.; Petagna, P.; Postema, H.; Verlaat, B.; Zwalinski, L.

    2016-01-01

    In the last few years, CO_2 evaporative cooling has been one of the favourite technologies chosen for the thermal management of tracking detectors at LHC. ATLAS Insertable B-Layer and CMS Pixel phase 1 upgrade have adopted it and their systems are now operational or under commissioning. The CERN PH-DT team is now merging the lessons learnt on these two systems in order to prepare the design and construction of the cooling systems for the new Upstream Tracker and the Velo upgrade in LHCb, due by 2018. Meanwhile, the preliminary design of the ATLAS and CMS full tracker upgrades is started, and both concepts heavily rely on CO_2 evaporative cooling. This paper highlights the performances of the systems now in operation and the challenges to overcome in order to scale them up to the requirements of the future generations of trackers. In particular, it focuses on the conceptual design of a new cooling system suited for the large phase 2 upgrade programmes, which will be validated with the construction of a common prototype in the next years.

  1. Fabrication of mesoporous silica/polymer composites through solvent evaporation process and investigation of their excellent low thermal expansion property.

    Science.gov (United States)

    Suzuki, Norihiro; Kiba, Shosuke; Yamauchi, Yusuke

    2011-03-21

    We fabricate mesoporous silica/epoxy polymer composites through a solvent evaporation process. The easy penetration of the epoxy polymers into mesopores is achieved by using a diluted polymer solution including a volatile organic solvent. After the complete solvent evaporation, around 90% of the mesopores are estimated to be filled with the epoxy polymer chains. Here we carefully investigate the thermal expansion behavior of the obtained mesoporous silica/polymer composites. Thermal mechanical analysis (TMA) charts revealed that coefficient of linear thermal expansion (CTE) gradually decreases, as the amount of the doped mesoporous silica increases. Compared with spherical silica particle without mesopores, mesoporous silica particles show a greater effect on lowering the CTE values. Interestingly, it is found that the CTE values are proportionally decreased with the decrease of the total amount of the polymers outside the mesopores. These data demonstrate that polymers embedded inside the mesopores become thermally stable, and do not greatly contribute to the thermal expansion behavior of the composites.

  2. Flash evaporator

    OpenAIRE

    1997-01-01

    A device and method for flash evaporating a reagent includes an evaporation chamber that houses a dome on which evaporation occurs. The dome is solid and of high thermal conductivity and mass, and may be heated to a temperature sufficient to vaporize a specific reagent. The reagent is supplied from an external source to the dome through a nozzle, and may be supplied as a continuous stream, as a shower, and as discrete drops. A carrier gas may be introduced into the evaporation chamber and cre...

  3. Influence of multi-depositions on the final properties of thermally evaporated TlBr films

    International Nuclear Information System (INIS)

    Destefano, N.; Mulato, M.

    2010-01-01

    Thallium bromide is a promising candidate material for photodetectors in medical imaging systems. This work investigates the structural, optical and electrical properties of thermally evaporated TlBr films. The main fabrication parameter is the number of depositions. The use of sequential runs is aimed to increase the thickness of the films, as necessary, for technological applications. We deposited films using one-four runs, that led to maximum thickness of about 50 μm. Crystallographic and morphological changes were observed with varying deposition runs. Nevertheless, the optical gap and electrical resistivity in the dark remained constant at about 2.85 eV and 10 9 Ω cm, respectively. Thicker samples have a larger ratio of photo-to-dark signal under medical X-ray exposure, with a larger linear region as a function of applied voltage. The results are discussed aiming at future technological applications in medical imaging.

  4. Electrical transport properties of thermally evaporated phthalocyanine (H 2Pc) thin films

    Science.gov (United States)

    El-Nahass, M. M.; Farid, A. M.; Attia, A. A.; Ali, H. A. M.

    2006-08-01

    Thin films of H 2Pc of various thicknesses have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperatures in the range 298-473 K. An estimation of mean free path ( lo) of charge carriers in H 2Pc thin films was attempted. Measurements of thermoelectric power confirm that H 2Pc thin films behave as a p-type semiconductor. The current density-voltage characteristics of Au/H 2Pc/Au at room temperature showed ohmic conduction mechanism at low voltages. At higher voltages the space-charge-limited conduction (SCLC) accompanied by an exponential trap distribution was dominant. The temperature dependence of current density allows the determination of some essential parameters such as the hole mobility ( μh), the total trap concentration ( Nt), the characteristic temperature ( Tt) and the trap density P( E).

  5. The anomalous low temperature resistivity of thermally evaporated α-Mn thin film

    International Nuclear Information System (INIS)

    Ampong, F.K.; Boakye, F.; Nkum, R.K.

    2010-01-01

    Electrical resistivity measurements have been carried out on thermally evaporated α-Mn thin film between 300 and 1.4 K using the van der Pauw four probe technique. The film was grown on a glass substrate held at a temperature of 373 K, in an ambient pressure of 5x10 -6 Torr. The results show a resistance minimum, a notable characteristic of α-Mn but at a (rather high) temperature of 194±1 K. Below the resistivity maximum which corresponds to 70 K, the resistivity drops by only 0.02 μΩm indicating a rather short range magnetic ordering. The low temperature results show a tendency towards saturation of the resistivity as the temperature approaches zero suggesting a Kondo scattering.

  6. The anomalous low temperature resistivity of thermally evaporated alpha-Mn thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ampong, F.K., E-mail: kampxx@yahoo.co [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Boakye, F.; Nkum, R.K. [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

    2010-08-15

    Electrical resistivity measurements have been carried out on thermally evaporated alpha-Mn thin film between 300 and 1.4 K using the van der Pauw four probe technique. The film was grown on a glass substrate held at a temperature of 373 K, in an ambient pressure of 5x10{sup -6} Torr. The results show a resistance minimum, a notable characteristic of alpha-Mn but at a (rather high) temperature of 194+-1 K. Below the resistivity maximum which corresponds to 70 K, the resistivity drops by only 0.02 muOMEGAm indicating a rather short range magnetic ordering. The low temperature results show a tendency towards saturation of the resistivity as the temperature approaches zero suggesting a Kondo scattering.

  7. Synthesis of GeSe2 Nanobelts Using Thermal Evaporation and Their Photoelectrical Properties

    Directory of Open Access Journals (Sweden)

    Lijie Zhang

    2014-01-01

    Full Text Available GeSe2 nanobelts were synthesized via a simple thermal-evaporation process by using gold particles as catalyst and GeSe2 flakes as starting materials. The morphology, crystal structure, and composition were characterized with scanning electron microscopy (SEM, high-resolution transmission electron microscopy (TEM, X-ray diffraction spectroscopy (XRD, X-ray photoelectron spectroscopy (XPS, and energy-dispersive X-ray spectroscopy (EDS. SEM micrographs show that most of GeSe2 nanobelts have distinct segmented structures (wide belt, zigzag belt, and narrow belt. A possible mechanism was proposed for the growth of segmented nanobelts. It is possible that the growth of the segmented nanobelts is dominated by both vapor-liquid-solid and vapor-solid mechanisms. Devices made of single GeSe2 nanobelt have been fabricated and their photoelectrical property has been investigated. Results indicate that these nanobelt devices are potential building blocks for optoelectronic applications.

  8. Simultaneous determination of mass and thermal accommodation coefficients from temporal evolution of an evaporating water microdroplet

    International Nuclear Information System (INIS)

    Zientara, M; Jakubczyk, D; Derkachov, G; Kolwas, K; Kolwas, M

    2005-01-01

    Scattering of coherent light by an evaporating droplet of pure water several micrometres in size was investigated. The droplet was levitated in an electrodynamic trap placed in a small climatic chamber. The evolution of the droplet radius and the evolution dynamics were investigated by means of analysing the scattering patterns with the aid of Mie theory. A numerical model of droplet evolution, incorporating the kinetic effects near the droplet surface, was constructed. Application of this model to the experimental data allowed us to determine the mass and thermal accommodation coefficients to be α C = 0.12 ± 0.02 and α T = 0.65 ± 0.09, respectively. This model enabled us to determine with high precision the temperature evolution of the droplet and the relative humidity in the droplet vicinity

  9. Theoretical assessment of evaporation rate of isolated water drop under the conditions of cooling tower of thermal power plant

    Directory of Open Access Journals (Sweden)

    Shevelev Sergey

    2017-01-01

    Full Text Available The purpose of the work is numerical modelling of heat and mass transfer at evaporation of water drops under the conditions which are typical for a modern chimney-type cooling tower of a thermal power plant. The dual task of heat and mass transfer with movable boundary at convective cooling and evaporation for a ‘drop–humid air’ system in a spherical coordinate system has been solved. It has been shown that there is a rapid decline of water evaporation rate at the initial stage of the process according to temperature decrease of its surface. It has been stated that the effect of evaporation rate decrease appears greatly in the area of small radiuses.

  10. Control of the Thermal Evaporation of Organic Semiconductors via Exact Linearization

    OpenAIRE

    Martin Steinberger; Martin Horn

    2011-01-01

    In this article, a high vacuum system for the evaporation of organic semiconductors is introduced and a mathematical model is given. Based on the exact input output linearization a deposition rate controller is designed and tested with different evaporation materials.

  11. Magnetic field and temperature dependent measurements of hall coefficient in thermal evaporated Tin-Doped Cadmium Oxide Thin films

    International Nuclear Information System (INIS)

    Hamadi, O.; Shakir, N.; Mohammed, F.

    2010-01-01

    CdO:Sn thin films are deposited onto glass substrates by thermal evaporation under vacuum. The studied films are polycrystalline and have an NaCl structure. The Hall effect is studied for films with different thickness as substrates are maintained at different temperatures. The temperature dependence of the Hall mobility is also investigated. (authors)

  12. Thermal behavior of human eye in relation with change in blood perfusion, porosity, evaporation and ambient temperature.

    Science.gov (United States)

    Rafiq, Aasma; Khanday, M A

    2016-12-01

    Extreme environmental and physiological conditions present challenges for thermal processes in body tissues including multi-layered human eye. A mathematical model has been formulated in this direction to study the thermal behavior of the human eye in relation with the change in blood perfusion, porosity, evaporation and environmental temperatures. In this study, a comprehensive thermal analysis has been performed on the multi-layered eye using Pennes' bio-heat equation with appropriate boundary and interface conditions. The variational finite element method and MATLAB software were used for the solution purpose and simulation of the results. The thermoregulatory effect due to blood perfusion rate, porosity, ambient temperature and evaporation at various regions of human eye was illustrated mathematically and graphically. The main applications of this model are associated with the medical sciences while performing laser therapy and other thermoregulatory investigation on human eye. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Optical and electrical properties of thermally evaporated In49Se48Sn3 films

    International Nuclear Information System (INIS)

    Salem, A.M.; El-Gendy, Y.A.; El-Sayad, E.A.

    2009-01-01

    Nearly stoichiometric thin films of In 49 Se 48 Sn 3 were deposited at room temperature, by conventional thermal evaporation of the presynthesized materials, onto precleaned glass substrates. The microstructural studies on the as-deposited and annealed films, using transmission electron microscopy and diffraction (TEMD), revealed that the as-deposited films are amorphous in nature, while those annealed at 498 K are crystalline. The optical properties of the investigated films were determined from the transmittance and reflectance data, in the spectral range 650-2500 nm. An analysis of the optical absorption spectra revealed a non-direct energy gap characterizing the amorphous films, while both allowed and forbidden direct energy gaps characterized the crystalline films. The electrical resistance of the deposited films was carried out during heating and cooling cycles in the temperature range 300-600 K. The results show an irreproducible behavior, while after crystallization the results become reproducible. The analysis of the temperature dependence of the resistance (ln(R) vs. 1000/T) for crystalline films shows two straight lines corresponding to both extrinsic and intrinsic conduction. The room temperature I-V characteristics of the as-deposited films sandwiched between similar Ag metal electrodes shows an ohmic behavior, while non-ohmic behavior attributed to space charge limited conduction has been observed when the films are sandwiched between dissimilar Ag/Al metal electrodes.

  14. Synthesis and optical properties of flower-like ZnO nanorods by thermal evaporation method

    International Nuclear Information System (INIS)

    Zheng, J.H.; Jiang, Q.; Lian, J.S.

    2011-01-01

    Flower-like ZnO nanorods have been synthesized by heating a mixture of ZnO/graphite powders using the thermal evaporation and vapor transport on Si (1 0 0) substrates without any catalyst. The structures, morphologies and optical properties of the products were characterized in detail by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Raman spectroscopy. The synthesized products consisted of large quantities of flower-like ZnO nanostructures in the form of uniform nanorods. The flower-like ZnO nanorods had high purity and well crystallized wurtzite structure, whose high crystalline quality was proved by Raman spectroscopy. The as-synthesized flower-like ZnO nanorods showed a strong ultraviolet emission at 386 nm and a weak and broad yellow-green emission in visible spectrum in its room temperature photoluminescence (PL) spectrum. In addition, the growth mechanism of the flower-like ZnO nanorods was discussed based on the reaction conditions.

  15. Physical properties of very thin SnS films deposited by thermal evaporation

    International Nuclear Information System (INIS)

    Cheng Shuying; Conibeer, Gavin

    2011-01-01

    SnS films with thicknesses of 20–65 nm have been deposited on glass substrates by thermal evaporation. The physical properties of the films were investigated using X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultraviolet–visible-near infrared spectroscopy at room temperature. The results from XRD, XPS and Raman spectroscopy analyses indicate that the deposited films mainly exhibit SnS phase, but they may contain a tiny amount of Sn 2 S 3 . The deposited SnS films are pinhole free, smooth and strongly adherent to the surfaces of the substrates. The color of the SnS films changes from pale yellow to brown with the increase of the film thickness from 20 nm to 65 nm. The very smooth surfaces of the thin films result in their high reflectance. The direct bandgap of the films is between 2.15 eV and 2.28 eV which is much larger than 1.3 eV of bulk SnS, this is deserving to be investigated further.

  16. Synthesis and characterization of thermally evaporated Cu2SnSe3 ternary semiconductor

    Science.gov (United States)

    Hamdani, K.; Chaouche, M.; Benabdeslem, M.; Bechiri, L.; Benslim, N.; Amara, A.; Portier, X.; Bououdina, M.; Otmani, A.; Marie, P.

    2014-11-01

    Copper Tin Selenide (CuSnSe) powder was mechanically alloyed by high energy planetary ball milling, starting from elemental powders. Synthesis time and velocity have been optimized to produce Cu2SnSe3 materials. Thin films were prepared by thermal evaporation on Corning glass substrate at Ts = 300 °C. The structural, compositional, morphological and optical properties of the synthesized semiconductor have been analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and transmission electron microscopy. The analyzed powder exhibited a cubic crystal structure, with the presence of Cu2Se as a secondary phase. On the other hand, the deposited films showed a cubic Cu2SnSe3 ternary phase and extra peaks belonging to some binary compounds. Furthermore, optical measurements showed that the deposited layers have a relatively high absorption coefficient of 105 cm-1 and present a band gap of 0.94 eV.

  17. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions

    KAUST Repository

    Alpatova, Alla; Alsaadi, Ahmad Salem; Ghaffour, NorEddine

    2018-01-01

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO scaling on the membrane surface.

  18. Studies on the optoelectronic properties of the thermally evaporated tin-doped indium oxide nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ko-Ying [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Lin, Liang-Da [Institute of Materials Science and Nanotechnology, Chinese Culture University, Taipei 111, Taiwan, ROC (China); Chang, Li-Wei [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Shih, Han C., E-mail: hcshih@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Institute of Materials Science and Nanotechnology, Chinese Culture University, Taipei 111, Taiwan, ROC (China)

    2013-05-15

    Indium oxide (In{sub 2}O{sub 3}) nanorods, nanotowers and tin-doped (Sn:In = 1:100) indium oxide (ITO) nanorods have been fabricated by thermal evaporation. The morphology, microstructure and chemical composition of these three nanoproducts are characterized by FE-SEM, HRTEM and XPS. To further investigate the optoelectronic properties, the I–V curves and cathodoluminescence (CL) spectra are measured. The electrical resistivity of In{sub 2}O{sub 3} nanorods, nanotowers and ITO nanorods are 1.32 kΩ, 0.65 kΩ and 0.063 kΩ, respectively. CL spectra of these three nanoproducts clearly indicate that tin-doped (Sn:In = 1:100) indium oxide (ITO) nanorods cause a blue shift. No doubt ITO nanorods obtain the highest performance among these three nanoproducts, and this also means that Sn-doped In{sub 2}O{sub 3} nanostructures would be the best way to enhance the optoelectronic properties. Additionally, the growing mechanism and the optoelectronic properties of these three nanostructures are discussed. This study is beneficial to the applications of In{sub 2}O{sub 3} nanorods, nanotowers and ITO nanorods in optoelectronic nanodevices.

  19. Fabrication and characterization of In2S3 thin films deposited by thermal evaporation technique

    International Nuclear Information System (INIS)

    Timoumi, A.; Bouzouita, H.; Kanzari, M.; Rezig, B.

    2005-01-01

    Indium sulphide, In 2 S 3 , thin films present an alternative to conventional CdS films as buffer layer for CIS-based thin film solar cells. The objective is to eliminate toxic cadmium for environmental reasons. Indium sulphide is synthesized and deposited by single source vacuum thermal evaporation method on glass substrates. The films are analyzed by X-ray diffraction (XRD) and spectrophotometric measurements. They have a good crystallinity, homogeneity and adhesion. The X-ray diffraction analysis confirmed the initial amorphous nature of the deposited InS film and phase transition into crystalline In 2 S 3 formed upon annealing at free air for 250 deg. C substrate temperature for 2 h. The optical constants of the deposited films were obtained from the analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range of 300-1800 nm. We note that the films annealed at 250 deg. C for 2 h show a good homogeneity with 80% transmission. An analysis of the optical absorption data of the deposited films revealed an optical direct band gap energy in the range of 2.0-2.2 eV

  20. Comparison of structural properties of thermally evaporated CdTe thin films on different substrates

    International Nuclear Information System (INIS)

    Tariq, G.H.; Anis-ur-Rehman, M.

    2011-01-01

    The direct energy band gap in the range of 1.5 eV and the high absorption coefficient (105 cm/sup -1/) makes Cadmium Telluride (CdTe) a suitable material for fabrication of thin film solar cells. Thin film solar cells based on CdTe (1 cm area) achieved efficiency of 15.6% on a laboratory scale. CdTe thin films were deposited by thermal evaporation technique under vacuum 2 X 10/sup -5/mbar on glass and stainless steel (SS) substrates. During deposition substrates temperature was kept same at 200 deg. C for all samples. The structural properties were determined by the X-ray Diffraction (XRD) patterns. All samples exhibit polycrystalline nature. Dependence of different structural parameters such as lattice parameter, micro strain, and grain size and dislocation density on thickness was studied. Also the influence of the different substrates on these parameters was investigated. The analysis showed that the preferential orientation of films was dependent on the substrate type. (author)

  1. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions.

    Science.gov (United States)

    Alpatova, A; Alsaadi, A; Ghaffour, N

    2018-06-05

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO 3 scaling on the membrane surface. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K.; Al-Busaidi, M.; Gismelseed, A.; Al-Rawas, A. [Physics Department, College of Science, Sultan Qabos University, P. O. Box 36, Postal Code 123, Al-Khodh, Muscat (Oman)

    2004-05-01

    Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers (MLs) have been investigated. Although multilayered structure has been successfully obtained, a substantial interfacial roughness ranging from 0.6 nm to 1.2 nm has been determined. All Fe/Cu MLs were polycrystalline with an average grain size of about 10 nm. Fe was bcc and textured (110) whereas Cu was fcc(111). Transmission electron microscopy analysis showed that the fcc Cu layer was rather textured (110) and (100) at least in the first stage of growth of the Fe/Cu MLs. Conversion electron Moessbauer (CEMS) measurements indicated the existence of three phases. Two of them were magnetic with a dominant bcc Fe phase, followed by fcc Fe phase. The third phase was superparamagnetic. The CEMS results were explained in terms of the partial diffusion of Fe into Cu with three different zones. The small magnetoresistance (MR<0.2%) was correlated to Fe clusters located at Fe-Cu interfaces. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  3. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    International Nuclear Information System (INIS)

    Tripathy, Sumanta K.; Rajeswari, V. P.

    2014-01-01

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn 3 O 4 , corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells

  4. Investigation of nanocrystalline thin cobalt films thermally evaporated on Si(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, W., E-mail: wkozl@std2.phys.uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Balcerski, J.; Szmaja, W. [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Piwoński, I. [Department of Materials Technology and Chemistry, Faculty of Chemistry, University of Łódź, Pomorska 163, 90-236 Łódź (Poland); Batory, D. [Institute of Materials Science and Engineering, Łódź University of Technology, Stefanowskiego 1/15, 90-924 Łódź (Poland); Miękoś, E. [Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź (Poland); and others

    2017-03-15

    We have made a quantitative study of the morphological and magnetic domain structures of 100 nm thick nanocrystalline cobalt films thermally evaporated on naturally oxidized Si(100) substrates. The morphological structure is composed of densely packed grains with the average grain size (35.6±0.8) nm. The grains exhibit no geometric alignment and no preferred elongation on the film surface. In the direction perpendicular to the film surface, the grains are aligned in columns. The films crystallize mainly in the hexagonal close-packed phase of cobalt and possess a crystallographic texture with the hexagonal axis perpendicular to the film surface. The magnetic domain structure consists of domains forming a maze stripe pattern with the average domain size (102±6) nm. The domains have their magnetizations oriented almost perpendicularly to the film surface. The domain wall energy, the domain wall thickness and the critical diameter for single-domain particle were determined. - Highlights: • 100 nm thick nanocrystalline cobalt films on Si(100) were studied quantitatively. • The grains are densely packed and possess the average size (35.6±0.8) nm. • The films have a texture with the hexagonal axis perpendicular to the film surface. • The magnetic domains form a maze stripe pattern with the average size (102±6) nm. • The domains are magnetized almost perpendicularly to the film surface.

  5. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions

    KAUST Repository

    Alpatova, Alla

    2018-03-26

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO scaling on the membrane surface.

  6. Enhancement in microstructural and optoelectrical properties of thermally evaporated CdTe films for solar cells

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2018-03-01

    The optimization of microstructural and optoelectrical properties of a thin layer is an important step prior device fabrication process, so an enhancement in these properties of thermally evaporated CdTe thin films is reported in this communication. The films having thickness 450 nm and 850 nm were deposited on thoroughly cleaned glass and indium tin oxide (ITO) substrates followed by annealing at 450 °C in air atmosphere. These films were characterized for microstructural and optoelectrical properties employing X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, UV-Vis spectrophotometer and source meter. The films found to be have zinc-blende cubic structure with preferred reflection (111) while the crystallographic parameters and direct energy band gap are strongly influenced by the film thickness. The surface morphology studies show that the films are uniform, smooth, homogeneous and nearly dense-packed as well as free from voids and pitfalls as where elemental analysis revealed the presence of Cd and Te element in the deposited films. The electrical analysis showed linear behavior of current with voltage while conductivity is decreased for higher thickness. The results show that the microstructural and optoelectrical properties of CdTe thin layer could be enhanced by varying thickness and films having higher thickness might be processed as promising absorber thin layer to the CdTe-based solar cells.

  7. Supramolecular structure of a perylene derivative in thin films made by vacuum thermal evaporation

    International Nuclear Information System (INIS)

    Fernandes, Jose Diego

    2015-01-01

    The supramolecular arrangement of organic thin films is a factor that influences both optical and electrical properties of these films and, consequently, the technological applications involving organic electronics. In this dissertation, thin films of a perylene derivative (bis butylimido perylene, acronym BuPTCD) were produced by physical vapor deposition (PVD) using vacuum thermal evaporation. The aim of this work was to investigate the supramolecular arrangement of BuPTCD films, which implies to control the thickness at nanometer scale and to determine the molecular organization, the morphology (at nano and micrometer scales) and the crystallinity, besides the stability of this arrangement as a function of the temperature. Optical properties (such as absorption and emission) and electrical properties (such as conductivity and photoconductivity) were also determined. The UV-Vis absorption spectra revealed a controlled growth (uniform) of the BuPTCD films. Atomic force and optical microscopy images showed a homogeneous surface of the film at nano and micrometer scales, respectively. The X-ray diffraction showed that the BuPTCD powder and PVD film have different crystalline structures, with the BuPTCD molecules head-on oriented in the PVD films, supported on the substrate surface by the side group (FTIR). This structure favors the light emission (photoluminescence) by the formation of excimers. The thermal treatment (200°C for 10 min) does not affect the molecular organization of the PVD films, showing a thermal stability of the BuPTCD supramolecular arrangement under these circumstances. The electrical measurements (DC) showed a linear increase of the current as a function of the tension, which is characteristic of ohmic behavior. Also, the films exhibited an increase of current by 2 orders of magnitude when exposed to light (photoconductive properties). Finally, BuPTCD films were exposed to vapor of trifluoroacetic acid (TFA) to verify the sensitivity of the Bu

  8. Validation of the RALOC-mod.4 thermal-hydraulics code on evaporation transients in the Phebus containment

    International Nuclear Information System (INIS)

    Spitz, P.B.; Lemoine, F.; Tirini, S.

    1997-01-01

    IPSN (Nuclear Protection and Safety Institute) and GRS (Gesellschaft fur Anlagen und Reaktorsicherheit Schwertnergasse 1) are developing the ESCADRE-ASTEC systems of codes devoted to the prediction of the behaviour of water-cooled reactors during a severe accident. The RALOC-mod 4 code belongs to this system and is specifically devoted to containment thermal-hydraulics studies. IPSN has designed a Thermal Hydraulic Containment Test Program in support to the Phebus Fission Product Test Program/2/. Evaporation tests have been recently performed in the Phebus containment test facility. The objective of this work is to assess against these tests the capability of the RALOC -mod 4 code to capture the phenomena observed in these experiments and more particularly the evaporation heat transfer and wall heat transfers. (DM)

  9. Thermal management of metallic surfaces: evaporation of sessile water droplets on polished and patterned stainless steel

    Science.gov (United States)

    Czerwiec, T.; Tsareva, S.; Andrieux, A.; Bortolini, G. A.; Bolzan, P. H.; Castanet, G.; Gradeck, M.; Marcos, G.

    2017-10-01

    This communication focus on the evaporation of sessile water droplets on different states of austenitic stainless steel surfaces: mirror polished, mirror polished and aged and patterned by sputtering. The evolution of the contact angle and of the droplet diameter is presented as a function of time at room temperature. For all the surface states, a constant diameter regime (CCR) is observed. An important aging effect on the contact angle is measured on polished surfaces due to atmospheric contamination. The experimental observations are compared to a quasi-static evaporation model assuming spherical caps. The evolution of the droplet volume as a function of time is almost linear with the evaporation time for all the observed surfaces. This is in accordance with the model prediction for the CCR mode for small initial contact angles. In our experiments, the evaporation time is found to be linearly dependent on the initial contact angle. This dependence is not correctly described by the evaporation model

  10. The Evaporation and Survival of Cluster Galaxy Coronae. I. The Effectiveness of Isotropic Thermal Conduction Including Saturation

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaraghavan, Rukmani; Sarazin, Craig, E-mail: rukmani@virginia.edu [Department of Astronomy, University of Virginia, 530 McCormick Rd., Charlottesville, VA 22904 (United States)

    2017-05-20

    We simulate the evolution of cluster galaxy hot interstellar medium (ISM) gas that is a result of the effects of ram pressure and thermal conduction in the intracluster medium (ICM). At the density and temperature of the ICM, the mean free paths of ICM electrons are comparable to the sizes of galaxies, therefore electrons can efficiently transport heat that is due to thermal conduction from the hot ICM to the cooler ISM. Galaxies consisting of dark matter halos and hot gas coronae are embedded in an ICM-like “wind tunnel” in our simulations. In this paper, we assume that thermal conduction is isotropic and include the effects of saturation. We find that as heat is transferred from the ICM to the ISM, the cooler denser ISM expands and evaporates. This process is significantly faster than gas loss due to ram pressure stripping; for our standard model galaxy, the evaporation time is 160 Myr, while the ram pressure stripping timescale is 2.5 Gyr. Thermal conduction also suppresses the formation of shear instabilities, and there are no stripped ISM tails since the ISM evaporates before tails can form. Observations of long-lived X-ray emitting coronae and ram pressure stripped X-ray tails in galaxies in group and cluster environments therefore require that thermal conduction is suppressed or offset by some additional physical process. The most likely process is anisotropic thermal conduction that is due to magnetic fields in the ISM and ICM, which we simulate and study in the next paper in this series.

  11. The Evaporation and Survival of Cluster Galaxy Coronae. I. The Effectiveness of Isotropic Thermal Conduction Including Saturation

    International Nuclear Information System (INIS)

    Vijayaraghavan, Rukmani; Sarazin, Craig

    2017-01-01

    We simulate the evolution of cluster galaxy hot interstellar medium (ISM) gas that is a result of the effects of ram pressure and thermal conduction in the intracluster medium (ICM). At the density and temperature of the ICM, the mean free paths of ICM electrons are comparable to the sizes of galaxies, therefore electrons can efficiently transport heat that is due to thermal conduction from the hot ICM to the cooler ISM. Galaxies consisting of dark matter halos and hot gas coronae are embedded in an ICM-like “wind tunnel” in our simulations. In this paper, we assume that thermal conduction is isotropic and include the effects of saturation. We find that as heat is transferred from the ICM to the ISM, the cooler denser ISM expands and evaporates. This process is significantly faster than gas loss due to ram pressure stripping; for our standard model galaxy, the evaporation time is 160 Myr, while the ram pressure stripping timescale is 2.5 Gyr. Thermal conduction also suppresses the formation of shear instabilities, and there are no stripped ISM tails since the ISM evaporates before tails can form. Observations of long-lived X-ray emitting coronae and ram pressure stripped X-ray tails in galaxies in group and cluster environments therefore require that thermal conduction is suppressed or offset by some additional physical process. The most likely process is anisotropic thermal conduction that is due to magnetic fields in the ISM and ICM, which we simulate and study in the next paper in this series.

  12. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Sumanta K.; Rajeswari, V. P. [Centre for Nano Science and Technology, GVP College of Engineering (Autonomous), Visakhapatnam- 530048 (India)

    2014-01-28

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  13. Thermally evaporated thin films of SnS for application in solar cell devices

    International Nuclear Information System (INIS)

    Miles, Robert W.; Ogah, Ogah E.; Zoppi, Guillaume; Forbes, Ian

    2009-01-01

    SnS (tin sulphide) is of interest for use as an absorber layer and the wider energy bandgap phases e.g. SnS 2 , Sn 2 S 3 and Sn/S/O alloys of interest as Cd-free buffer layers for use in thin film solar cells. In this work thin films of tin sulphide have been thermally evaporated onto glass and SnO 2 :coated glass substrates with the aim of optimising the properties of the material for use in photovoltaic solar cell device structures. In particular the effects of source temperature, substrate temperature, deposition rate and film thickness on the chemical and physical properties of the layers were investigated. Energy dispersive X-ray analysis was used to determine the film composition, X-ray diffraction to determine the phases present and structure of each phase, transmittance and reflectance versus wavelength measurements to determine the energy bandgap and scanning electron microscopy to observe the surface topology and topography and the properties correlated to the deposition parameters. Using the optimised conditions it is possible to produce thin films of tin sulphide that are pinhole free, conformal to the substrate and that consist of densely packed columnar grains. The composition, phases present and the optical properties of the layers deposited were found to be highly sensitive to the deposition conditions. Energy bandgaps in the range 1.55 eV-1.7 eV were obtained for a film thickness of 0.8 μm, and increasing the film thickness to > 1 μm resulted in a reduction of the energy bandgap to less than 1.55 eV. The applicability of using these films in photovoltaic solar cell device structures is also discussed.

  14. Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation

    Directory of Open Access Journals (Sweden)

    Nurul Izni Rusli

    2012-12-01

    Full Text Available The formation of high-density zinc oxide (ZnO nanorods on porous silicon (PS substrates at growth temperatures of 600–1000 °C by a simple thermal evaporation of zinc (Zn powder in the presence of oxygen (O2 gas was systematically investigated. The high-density growth of ZnO nanorods with (0002 orientation over a large area was attributed to the rough surface of PS, which provides appropriate planes to promote deposition of Zn or ZnOx seeds as nucleation sites for the subsequent growth of ZnO nanorods. The geometrical morphologies of ZnO nanorods are determined by the ZnOx seed structures, i.e., cluster or layer structures. The flower-like hexagonal-faceted ZnO nanorods grown at 600 °C seem to be generated from the sparsely distributed ZnOx nanoclusters. Vertically aligned hexagonal-faceted ZnO nanorods grown at 800 °C may be inferred from the formation of dense arrays of ZnOx clusters. The formation of disordered ZnO nanorods formed at 1000 °C may due to the formation of a ZnOx seed layer. The growth mechanism involved has been described by a combination of self-catalyzed vapor-liquid-solid (VLS and vapor-solid (VS mechanism. The results suggest that for a more precise study on the growth of ZnO nanostructures involving the introduction of seeds, the initial seed structures must be taken into account given their significant effects.

  15. Effect of thickness on optical properties of thermally evaporated SnS films

    International Nuclear Information System (INIS)

    Selim, M.S.; Gouda, M.E.; El-Shaarawy, M.G.; Salem, A.M.; Abd El-Ghany, W.A.

    2013-01-01

    The effect of film thickness on the structure and optical properties of thermally evaporated SnS film has been studied. SnS films with different thicknesses in the range 152–585 nm were deposited onto clean glass substrates at room temperature. X-ray diffraction study revealed that SnS films of thickness ≥ 283 nm are crystalline, whereas films of lower thickness exhibit poor crystalline with more amorphous background. The crystalline nature of the lower film thickness has been confirmed using transmission electron microscope and the corresponding electron diffraction pattern. The thicker film samples showed nearly stoichiometric chemical composition; however, thinner samples are deficient in S and rich in Sn. The optical property of the deposited films has been investigated in the wavelength range 350–2500 nm. The refractive index increases notably with increasing film thickness. The refractive index for the investigated film thicknesses are adequately described by the effective-single-oscillator model. The static refractive index and the static dielectric constant have been calculated. Analysis of the optical absorption coefficient revealed the presence of direct optical transition and the corresponding band gap values were found to decrease as the film thickness increases. - Highlights: ► X-ray diffraction was used to study the structure of SnS films. ► Transmission electron microscope confirms the crystalline state of SnS films. ► The refractive index increases notably with increasing the film thickness. ► The optical band gap of SnS films decreases with increasing film thickness

  16. Comparison of the Al back contact deposited by sputtering, e-beam, or thermal evaporation for inverted perovskite solar cells

    Science.gov (United States)

    Wahl, Tina; Hanisch, Jonas; Ahlswede, Erik

    2018-04-01

    In this work, we present inverted perovskite solar cells with Al top electrodes, which were deposited by three different methods. Besides the widely used thermal evaporation of Al, we also used the industrially important high deposition rate processes sputtering and electron beam evaporation for aluminium electrodes and examined the influence of the deposition method on the solar cell performance. The current-voltage characteristics of as grown solar cells with sputtered and e-beam Al electrode show an s-shape due to damage done to the organic electronic transport layers (ETL) during Al deposition. It can be cured by a short annealing step at a moderate temperature so that fill factors  >60% and power conversion efficiencies of almost 12% with negligible hysteresis can be achieved. While solar cells with thermally evaporated Al electrode do not show an s-shape, they also exhibit a clear improvement after a short annealing step. In addition, we varied the thickness of the ETL consisting of a double layer ([6,6]-Phenyl-C61-butyric acid methyl ester and bathocuproine) and investigated the influence on the solar cell parameters for the three different Al deposition methods, which showed distinct dependencies on ETL thickness.

  17. Study of mixed radiative thermal mass transfer in the case of spherical liquide particle evaporation in a high temperature thermal air plasma

    International Nuclear Information System (INIS)

    Garandeau, S.

    1984-01-01

    Radiative transfer in a semi-transparent non-isothermal medium with spherical configuration has been studied. Limit conditions have been detailed, among which the semi-transparent inner sphere case is a new case. Enthalpy and matter transfer equations related to these different cases have been established. An adimensional study of local conservation laws allowed to reveal a parameter set characteristic of radiation coupled phenomena thermal conduction, convection, diffusion. Transfer equations in the case of evaporation of a liquid spherical particle in an air thermal plasma have been simplified. An analytical solution for matter transfer is proposed. Numerical solution of radiative problems and matter transfer has been realized [fr

  18. Influence of boat material on the structure, stoichiometry and optical properties of gallium sulphide films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Rao, Pritty; Kumar, Sanjiv; Sahoo, N.K.

    2015-01-01

    The paper describes the deposition of thin films of gallium sulphide on soda-lime glass substrates by thermal evaporation of chemically synthesized powders consisting of gallium sulphide and gallium oxyhydroxide from a Mo or Ta boat and the evolution of their compositional, structural and optical properties on vacuum annealing. The films deposited from Mo or Ta boats possessed distinctly different properties. The Mo-boat evaporated pristine films were amorphous, transparent (α ∼ 10 3  cm −1 ) in visible region and had a direct band gap of about 3.2 eV. Vacuum annealing at 723 K brought about their crystallization predominantly into cubic γ-Ga 2 S 3 and a blue shift by about 0.2 eV. The Ta-boat evaporated pristine films were also amorphous but were absorbing (α ∼ 10 4  cm −1 ) and had a direct band gap of about 2.1 eV. These crystallized into hexagonal GaS and experienced a blue shift by more than 1.0 eV on vacuum annealing at 723 K. The dissimilar properties of the two kinds of films arose mainly from their different atomic compositions. The Mo-boat evaporated pristine films contained Ga and S in ∼1:1 atomic proportions while those prepared using Ta-boat were Ga rich which impaired their transmission characteristics. The former composition favoured the stabilization of S rich gallium sulphide (Ga 2 S 3 ) phase while the latter stabilised S deficient species, GaS. Besides inducing crystallization, vacuum annealing at 723 K also caused the diffusion of Ga in excess of atomic composition of the phase formed, into soda-lime glass which improved the optical transmission of the films. Gallium oxyhydroxide, an inevitable co-product of the chemical synthetic process, in the evaporant introduced oxygen and hydrogen impurities in the films which do not seem to significantly influence their optical properties. - Highlights: • Gallium sulphide films are prepared by thermal evaporation from a Mo or Ta boat. • Mo-boat prepared pristine film has Ga

  19. Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control. Part 1; New Technologies and Validation Approach

    Science.gov (United States)

    Ku, Jentung; Ottenstein, Laura; Douglas, Donya; Hoang, Triem

    2010-01-01

    Under NASA s New Millennium Program Space Technology 8 (ST 8) Project, four experiments Thermal Loop, Dependable Microprocessor, SAILMAST, and UltraFlex - were conducted to advance the maturity of individual technologies from proof of concept to prototype demonstration in a relevant environment , i.e. from a technology readiness level (TRL) of 3 to a level of 6. This paper presents the new technologies and validation approach of the Thermal Loop experiment. The Thermal Loop is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers designed for future small system applications requiring low mass, low power, and compactness. The MLHP retains all features of state-of-the-art loop heat pipes (LHPs) and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. Details of the thermal loop concept, technical advances, benefits, objectives, level 1 requirements, and performance characteristics are described. Also included in the paper are descriptions of the test articles and mathematical modeling used for the technology validation. An MLHP breadboard was built and tested in the laboratory and thermal vacuum environments for TRL 4 and TRL 5 validations, and an MLHP proto-flight unit was built and tested in a thermal vacuum chamber for the TRL 6 validation. In addition, an analytical model was developed to simulate the steady state and transient behaviors of the MLHP during various validation tests. Capabilities and limitations of the analytical model are also addressed.

  20. Chemical states and optical properties of thermally evaporated Ge-Te and Ge-Sb-Te amorphous thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Singh, D.; Shandhu, S. [Semiconductor Laboratory, Department of Physics, Guru Nanak Dev University Amritsar (India); Thangaraj, R., E-mail: rthangaraj@rediffmail.com [Semiconductor Laboratory, Department of Physics, Guru Nanak Dev University Amritsar (India)

    2012-07-15

    Thin amorphous films of Ge{sub 22}Sb{sub 22}Te{sub 56} and Ge{sub 50}Te{sub 50} have been prepared from their respective polycrystalline bulk on glass substrates by thermal evaporation technique. The amorphous nature of the films was checked with X-ray diffraction studies. Amorphous-to-crystalline transition of the films has been induced by thermal annealing and the structural phases have been identified by X-ray diffraction. The phase transformation temperature of the films was evaluated by temperature dependent sheet resistance measurement. The chemical structure of the amorphous films has been investigated using X-ray photoelectron spectroscopy and the role of Sb in phase change Ge{sub 22}Sb{sub 22}Te{sub 56} film is discussed. Survey and core level (Ge 3d, Te 3d, Te 4d, Sb 3p, Sb 3d, O 1s, C 1s) band spectra has been recorded and analyzed. For optical studies, the transmittance and the reflectance spectra were measured over the wavelength ranges 400-2500 nm using UV-vis-NIR spectroscopy. The optical band gap, refractive index and extinction coefficient are also presented for thermally evaporated amorphous thin films.

  1. Analysis of energy saving performance for household refrigerator with thermal storage of condenser and evaporator

    International Nuclear Information System (INIS)

    Cheng, Wen-long; Ding, Miao; Yuan, Xu-dong; Han, Bing-Chuan

    2017-01-01

    Highlights: • A novel refrigerator with both HSC and CSE is proposed. • The operational characteristics of novel refrigerator is analyzed. • The comparison of CSE, HSC and DES refrigerators is analyzed. • DES refrigerator has a largest off-time to on-time ratio of 4.3. • DES refrigerator has the best electrical energy saving performance (32%). - Abstract: The heat transfer performances of evaporators and condensers significantly affect the efficiency of household refrigerators. For enhancing heat transfer of the condensers and evaporators, a novel dual energy storage (DES) refrigerator with both heat storage condenser (HSC) and cold storage evaporator (CSE) is proposed. The performance comparison of three kinds of energy storage refrigerators: HSC refrigerator, CSE refrigerator and DES refrigerator is analyzed by establishing dynamic simulation models. According to the simulation results, the DES refrigerator combines the advantage of HSC refrigerator and CSE refrigerator, it has more balanced operational cycle and higher evaporation pressure and temperature. The DES refrigerator shows a best energy saving performance among the three energy storage refrigerators with largest off-time to on-time ratio of 4.3 and the electrical consumption saving can reach 32%, which is greater than the sum (28%) of the other two kinds of energy storage refrigerators.

  2. Growth Structural and Optical Properties of the Thermally Evaporated Tin Diselenide (SnSe2) Thin Films

    OpenAIRE

    R. Sachdeva1,; M. Sharma1,; A. Devi1,; U. Parihar1,; N. Kumar1,; N. Padha1,; C.J. Panchal

    2011-01-01

    Tin diselenide (SnSe2) compound was prepared by melt-quenching technique from its constituent elements. The phase structure and composition of the chemical constituents present in the bulk has been determined using X-ray diffraction (XRD) and energy dispersion X-ray analysis (EDAX) respectively. SnSe2 thin films were grown using direct thermal evaporation of SnSe2 compound material on chemically cleaned glass substrate, which were held at different substrate temperatures. X-ray diffraction an...

  3. Remotely monitoring evaporation rate and soil water status using thermal imaging and "three-temperatures model (3T Model)" under field-scale conditions.

    Science.gov (United States)

    Qiu, Guo Yu; Zhao, Ming

    2010-03-01

    Remote monitoring of soil evaporation and soil water status is necessary for water resource and environment management. Ground based remote sensing can be the bridge between satellite remote sensing and ground-based point measurement. The primary object of this study is to provide an algorithm to estimate evaporation and soil water status by remote sensing and to verify its accuracy. Observations were carried out in a flat field with varied soil water content. High-resolution thermal images were taken with a thermal camera; soil evaporation was measured with a weighing lysimeter; weather data were recorded at a nearby meteorological station. Based on the thermal imaging and the three-temperatures model (3T model), we developed an algorithm to estimate soil evaporation and soil water status. The required parameters of the proposed method were soil surface temperature, air temperature, and solar radiation. By using the proposed method, daily variation in soil evaporation was estimated. Meanwhile, soil water status was remotely monitored by using the soil evaporation transfer coefficient. Results showed that the daily variation trends of measured and estimated evaporation agreed with each other, with a regression line of y = 0.92x and coefficient of determination R(2) = 0.69. The simplicity of the proposed method makes the 3T model a potentially valuable tool for remote sensing.

  4. Soil water content and evaporation determined by thermal parameters obtained from ground-based and remote measurements

    Science.gov (United States)

    Reginato, R. J.; Idso, S. B.; Jackson, R. D.; Vedder, J. F.; Blanchard, M. B.; Goettelman, R.

    1976-01-01

    Soil water contents from both smooth and rough bare soil were estimated from remotely sensed surface soil and air temperatures. An inverse relationship between two thermal parameters and gravimetric soil water content was found for Avondale loam when its water content was between air-dry and field capacity. These parameters, daily maximum minus minimum surface soil temperature and daily maximum soil minus air temperature, appear to describe the relationship reasonably well. These two parameters also describe relative soil water evaporation (actual/potential). Surface soil temperatures showed good agreement among three measurement techniques: in situ thermocouples, a ground-based infrared radiation thermometer, and the thermal infrared band of an airborne multispectral scanner.

  5. Thermoelectric properties of V{sub 2}O{sub 5} thin films deposited by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R.; Loureiro, J., E-mail: joa.loureiro@gmail.com; Nogueira, A.; Elangovan, E.; Pinto, J.V.; Veiga, J.P.; Busani, T.; Fortunato, E.; Martins, R.; Ferreira, I., E-mail: imf@fct.unl.pt

    2013-10-01

    This work reports the structural, optical, electrical and thermoelectric properties of vanadium pentoxide (V{sub 2}O{sub 5}) thin films deposited at room temperature by thermal evaporation on Corning glass substrates. A post-deposition thermal treatment up to 973 K under atmospheric conditions induces the crystallization of the as-deposited amorphous films with an orthorhombic V{sub 2}O{sub 5} phase with grain sizes around 26 nm. As the annealing temperature rises up to 773 K the electrical conductivity increases. The films exhibit thermoelectric properties with a maximum Seebeck coefficient of −218 μV/K and electrical conductivity of 5.5 (Ω m){sup −1}. All the films show NIR-Vis optical transmittance above 60% and optical band gap of 2.8 eV.

  6. Middle Electrode in a Vertical Transistor Structure Using an Sn Layer by Thermal Evaporation

    Science.gov (United States)

    Nogueira, Gabriel Leonardo; da Silva Ozório, Maiza; da Silva, Marcelo Marques; Morais, Rogério Miranda; Alves, Neri

    2018-05-01

    We report a process for performing the middle electrode for a vertical field effect transistor (VOFET) by the evaporation of a tin (Sn) layer. Bare aluminum oxide (Al2O3), obtained by anodization, and Al2O3 covered with a polymethylmethacrylate (PMMA) layer were used as the gate dielectric. We measured the electrical resistance of Sn while the evaporation was carried out to find the best condition to prepare the middle electrode, that is, good lateral conduction associated with openings that give permeability to the electric field in a vertical direction. This process showed that 55 nm Sn thick is suitable for use in a VOFET, being easier to achieve optimal thickness when the Sn is evaporated onto PMMA than onto bare Al2O3. The addition of a PMMA layer on the Al2O3 surface modifies the morphology of the Sn layer, resulting in a lowering of the threshold voltage. The values of threshold voltage and electric field, VTH = - 8 V and ETH = 354.5 MV/m respectively, were calculated using an Al2O3 film 20 nm thick covered with a 14 nm PMMA layer as gate dielectric, while for bare Al2O3 these values were VTH = - 10 V and ETH = 500 MV/m.

  7. Middle Electrode in a Vertical Transistor Structure Using an Sn Layer by Thermal Evaporation

    Science.gov (United States)

    Nogueira, Gabriel Leonardo; da Silva Ozório, Maiza; da Silva, Marcelo Marques; Morais, Rogério Miranda; Alves, Neri

    2018-03-01

    We report a process for performing the middle electrode for a vertical field effect transistor (VOFET) by the evaporation of a tin (Sn) layer. Bare aluminum oxide (Al2O3), obtained by anodization, and Al2O3 covered with a polymethylmethacrylate (PMMA) layer were used as the gate dielectric. We measured the electrical resistance of Sn while the evaporation was carried out to find the best condition to prepare the middle electrode, that is, good lateral conduction associated with openings that give permeability to the electric field in a vertical direction. This process showed that 55 nm Sn thick is suitable for use in a VOFET, being easier to achieve optimal thickness when the Sn is evaporated onto PMMA than onto bare Al2O3. The addition of a PMMA layer on the Al2O3 surface modifies the morphology of the Sn layer, resulting in a lowering of the threshold voltage. The values of threshold voltage and electric field, VTH = - 8 V and ETH = 354.5 MV/m respectively, were calculated using an Al2O3 film 20 nm thick covered with a 14 nm PMMA layer as gate dielectric, while for bare Al2O3 these values were VTH = - 10 V and ETH = 500 MV/m.

  8. Large-scale uniform ZnO tetrapods on catalyst free glass substrate by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Alsultany, Forat H., E-mail: foratusm@gmail.com [School of Physics, USM, 11800 Penang (Malaysia); Hassan, Z. [Institute of Nano-Optoelectronics Research and Technology Laboratory (INOR), USM, 11800 Penang (Malaysia); Ahmed, Naser M. [School of Physics, USM, 11800 Penang (Malaysia)

    2016-07-15

    Highlights: • Investigate the growth of ZnO-Ts on glass substrate by thermal evaporation method. • Glass substrate without any catalyst or a seed layer. • The morphology was controlled by adjusting the temperature of the material and the substrate. • Glass substrate was placed vertically in the quartz tube. - Abstract: Here, we report for the first time the catalyst-free growth of large-scale uniform shape and size ZnO tetrapods on a glass substrate via thermal evaporation method. Three-dimensional networks of ZnO tetrapods have needle–wire junctions, an average leg length of 2.1–2.6 μm, and a diameter of 35–240 nm. The morphology and structure of ZnO tetrapods were investigated by controlling the preparation temperature of each of the Zn powder and the glass substrate under O{sub 2} and Ar gases. Studies were carried out on ZnO tetrapods using X-ray diffraction, field emission scanning electron microscopy, UV–vis spectrophotometer, and a photoluminescence. The results showed that the sample grow in the hexagonal wurtzite structure with preferentially oriented along (002) direction, good crystallinity and high transmittance. The band gap value is about 3.27 eV. Photoluminescence spectrum exhibits a very sharp peak at 378 nm and a weak broad green emission.

  9. Growth of manganese sulfide (α-MnS) thin films by thermal vacuum evaporation: Structural, morphological and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Hannachi, Amira, E-mail: amira.hannachi88@gmail.com [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia); Segura, Alfredo [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Maghraoui-Meherzi, Hager [Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia)

    2016-09-15

    MnS thin films have been successfully prepared by thermal evaporation method at different substrate temperatures using different masses of MnS powder. The prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV–visible spectrophotometry. The XRD measurements show that the films crystallized in the pure α-MnS for substrate temperatures above 100 °C. The optical bandgap of thin films is found to be in the range of 3.2–3.3 eV. A factorial experimental design was used for determining the influence of the two experimental parameters on the films growth. - Highlights: • α-MnS films were deposited on glass and quartz substrates using the thermal evaporation technique. • The effect of substrate temperature on the properties of the MnS films has been studied. • The factorial design was used to determine the most influence parameters.

  10. Effect of the Evaporative Cooling on the Human Thermal Comfort and Heat Stress in a Greenhouse under Arid Conditions

    Directory of Open Access Journals (Sweden)

    A. M. Abdel-Ghany

    2013-01-01

    Full Text Available Thermal sensation and heat stress were evaluated in a plastic greenhouse, with and without evaporative cooling, under arid climatic conditions in Riyadh, Saudi Arabia. Suitable thermal comfort and heat stress scales were selected for the evaluation. Experiments were conducted in hot sunny days to measure the required parameters (i.e., the dry and wet bulb temperatures, globe temperature, natural wet bulb temperature, and solar radiation flux in the greenhouse. The results showed that in the uncooled greenhouse, workers are exposed to strong heat stress and would feel very hot most of the day time; they are safe from heat stress risk and would feel comfortable during night. An efficient evaporative cooling is necessary during the day to reduce heat stress and to improve the comfort conditions and is not necessary at night. In the cooled greenhouse, workers can do any activity: except at around noon they should follow a proposed working schedule, in which the different types of work were scheduled along the daytimes based on the heat stress value. To avoid heat stress and to provide comfort conditions in the greenhouses, the optimum ranges of relative humidity and air temperature are 48–55% and 24–28°C, respectively.

  11. Preliminary thermal/hydraulic sizing calculations for duplex tube evaporator/superheater (interchangeable units). Revision 1

    International Nuclear Information System (INIS)

    Waszink, R.P.; Hwang, J.Y.; Efferding, L.E.

    1974-06-01

    This is a preliminry thermal/hydraulic report reflecting work under Subtask 6.2 of Ref. 1.1. This report is an extension of the previous thermal/hydraulic design report. Parts of this report have been transmitted to GE. The detailed design basis, listed by source, is given. Additional details are discussed

  12. Investigation on thermal evaporated CH3NH3PbI3 thin films

    Directory of Open Access Journals (Sweden)

    Youzhen Li

    2015-09-01

    Full Text Available CH3NH3I, PbI2 and CH3NH3PbI3 films were fabricated by evaporation and characterized with X-ray Photoelectron Spectroscopy (XPS and X-ray diffraction (XRD. The XPS results indicate that the PbI2 and CH3NH3PbI3 films are more uniform and stable than the CH3NH3I film. The atomic ratio of the CH3NH3I, PbI2 and CH3NH3PbI3 films are C:N:I=1.00:1.01:0.70, Pb:I= 1.00:1.91 and C: N: Pb: I = 1.29:1.07:1.00:2.94, respectively. The atomic ratio of CH3NH3PbI3 is very close to that of the ideal perovskite. Small angle x-ray diffraction results demonstrate that the as evaporated CH3NH3PbI3 film is crystalline. The valence band maximum (VBM and work function (WF of the CH3NH3PbI3 film are about 0.85eV and 4.86eV, respectively.

  13. Biodiesel production through non-catalytic supercritical transesterification: current state and perspectives

    OpenAIRE

    Silva, C. da; Oliveira, J. Vladimir

    2014-01-01

    The inconveniences of the conventional method for biodiesel production by alkaline catalysis suggests research towards alternative methods, with the non-catalytic transesterification using an alcohol at supercritical conditions proposed as a promising technique for biodiesel production. The so-called supercritical method (SCM) has powerful advantages over conventional techniques, such as fast reaction rates, feedstock flexibility, production efficiency and environmentally friendly benefits. H...

  14. SNCR technology for NO sub x reduction in the cement industry. [Selective non-catalytic reduction

    Energy Technology Data Exchange (ETDEWEB)

    Kupper, D; Brentrup, L [Krupp Polysius AG, Beckum (Germany)

    1992-03-01

    This article discusses the selective non-catalytic (SNCR) process for reducing nitrogen oxides in exhaust gases from cement plants. Topics covered include operating experience, injection of additives, selection of the additive, operating costs, reduction efficiency of SNCR, capital expenditure, secondary emissions and cycles of ammonium. (UK).

  15. Molecular dynamics simulations for the motion of evaporative droplets driven by thermal gradients along nanochannels

    KAUST Repository

    Wu, Congmin; Xu, Xinpeng; Qian, Tiezheng

    2013-01-01

    -vapor coexistence temperature in one-component fluids while the solid surface is almost isothermal for solids of high thermal conductivity. Therefore, a temperature discontinuity is formed if the two isothermal interfaces are of different temperatures and intersect

  16. Solar thermal evaporation of human urine for nitrogen and phosphorus recovery in Vietnam

    International Nuclear Information System (INIS)

    Antonini, Samantha; Nguyen, Phong Thanh; Arnold, Ute; Eichert, Thomas; Clemens, Joachim

    2012-01-01

    A No Mix sanitation system was installed in a dormitory at the University of Can Tho in Vietnam, with the objective of recycling nutrients from source separated urine. This paper presents a pilot scale evaporation technology, and investigates the feasibility of recovering nitrogen and phosphorus from human urine by solar still for use as fertilizer. After 26 days of sun exposure, 360 g of solid fertilizer material was recovered from 50 L undiluted urine. This urine-derived fertilizer was mainly composed of sodium chloride, and had phosphorus and nitrogen contents of almost 2%. When tested with maize and ryegrass, the urine fertilizer led to biomass yields and phosphorus and nitrogen uptakes comparable to those induced by a commercial mineral fertilizer. Urine acidification with sulfuric or phosphoric acid prior treatment reduced nitrogen losses, improved the nutrient content of the generated fertilizers, and induced higher biomass yields and nitrogen and phosphorus uptakes than the commercial mineral fertilizer. However, acidification is not recommended in developing countries due to additional costs and handling risks. The fate of micropollutants and the possibility of separating sodium chloride from other beneficial nutrients require further investigation. - Highlights: ► 360 g of fertilizer was derived from 50 L urine by solar evaporative distillation. ► The fertilizer contained 90% sodium chloride, 3% sulfur, 2% nitrogen, 2% phosphorus. ► It induced biomass yields comparable to those produced by a commercial fertilizer. ► Urine acidification improved the nutrient content of the generated fertilizers. ► Acidification is not recommended for use in developing countries (costs, safety).

  17. Effects of mesh size in a flat evaporator and condenser cooling capacity on the thermal performance of a capillary pumped loop

    International Nuclear Information System (INIS)

    Boo, Joon Hong

    2000-01-01

    The thermal performance of a flat evaporator for Capillary Pumped Loop (CPL) applications was investigated. Two to four layers of coarse wire screen wicks were placed onto the heated surface to provide irregular passages for vapor flow. The evaporator and condenser were separated by a distance of 1.2 m and connected by individual liquid and vapor lines. The wall material was copper and the working fluid was ethanol. The experimental facility utilized a combination of capillary and gravitational forces for liquid return, and distribution over the evaporator surface. The tubing used for vapor and liquid lines was 9.35 mm or less in diameter and heat was removed from the condenser by convection of air. A heat flux of up to 4.9x10 4 W/m 2 was applied to a flat evaporator having dimensions of 100 mm by 200 mm, 20 mm thick. The thermal resistance of the system as well as the temperature characteristics of the system was investigated as the evaporator heat flux and the condenser cooling capacity varied. The performance of the evaporator and effect of condenser cooling capacity were analyzed and discussed

  18. Characterization of CuIn1-xAlxS2 thin films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Smaili, F.; Kanzari, M.; Rezig, B.

    2008-01-01

    Ingots containing single crystals of the quaternary alloys CuIn 1-x Al x S 2 (CIAS) were grown by a horizontal Bridgman method for compositions with x = 0, 0.2 and x = 0.4. (CIAS) thin films were prepared by thermal evaporation technique on to glass substrates. Structural and optical properties of the films were studied in function of the Al content. Band gap, and absorption coefficients were determined from the analysis of the optical spectra (transmittance and reflectance as a function of wavelength) recorded by a spectrophotometer. The samples have direct bandgap energies of 1.95 eV (x = 0), 2.06 eV (x = 0,2) and 2.1 eV (x = 0,4). These optical results were correlated with the structural analysis by X-Ray diffraction

  19. Observation of room temperature ferromagnetism in ZnTe:Cr films grown onto glass substrate by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Soundararajan, D; Mangalaraj, D; Nataraj, D [Thin Film Laboratory, Department of Physics, Bharathiar University, Coimbatore -641 046 (India); Dorosinskii, L [National Institute of Metrology (TUBITAK -UME), P.K. 54, 41470, Gebze -Kocaeli (Turkey); Santoyo-Salazar, J, E-mail: dorosins@ume.tubitak.gov.t [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, Mexico D.F. 04510 (Mexico)

    2009-03-01

    ZnTe and ZnTe:Cr films were prepared onto glass substrates using thermal evaporation method. Structural properties of the prepared samples were analyzed using X-ray diffractometer, and the presence of ZnCrTe phase was identified along with poor crystallinity. Composition analysis was done using XPS and the Cr content in the film was found to be 0.05 atomic percent. Transmittance spectra were recorded using UV-Vis spectrophotometer. The valence state of Cr in ZnTe:Cr film is determined to be +2 using electron spin resonance (ESR) spectroscopy. Magnetic moment data as a function of magnetic field were recorded using Superconducting Quantum Interference Device (SQUID) magnetometer at temperatures 5, 77 and 300 K. The results showed minority ferromagnetic behavior even at room temperature. Magnetic domains were observed using Magnetic Force Microscopy and the average value of domain size is 3.7 nm.

  20. Annealing effects on room temperature thermoelectric performance of p-type thermally evaporated Bi-Sb-Te thin films

    Science.gov (United States)

    Singh, Sukhdeep; Singh, Janpreet; Tripathi, S. K.

    2018-05-01

    Bismuth antimony telluride (Bi-Sb-Te) compounds have been investigated for the past many decades for thermoelectric (TE) power generation and cooling purpose. We synthesized this compound with a stoichiometry Bi1.2Sb0.8Te3 through melt cool technique and thin films of as synthesized material were deposited by thermal evaporation. The prime focus of the present work is to study the influence of annealing temperature on the room temperature (RT) power factor of thin films. Electrical conductivity and Seebeck coefficient were studied and power factors were calculated which showed a peak value at 323 K. The compounds performance is comparable to some very efficient Bi-Sb-Te reported stoichiometries at RT scale. The values observed show that material has an enormous potential for energy production at ambient temperature scales.

  1. Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Ronak Rahimi

    2013-01-01

    Full Text Available PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient have been extracted from the spectroscopic ellipsometry (SE. X-ray reflectivity (XRR and atomic force microscopy (AFM were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.

  2. BaSi2 formation mechanism in thermally evaporated films and its application to reducing oxygen impurity concentration

    Science.gov (United States)

    Hara, Kosuke O.; Yamamoto, Chiaya; Yamanaka, Junji; Arimoto, Keisuke; Nakagawa, Kiyokazu; Usami, Noritaka

    2018-04-01

    Thermal evaporation is a simple and rapid method to fabricate semiconducting BaSi2 films. In this study, to elucidate the BaSi2 formation mechanism, the microstructure of a BaSi2 epitaxial film fabricated by thermal evaporation has been investigated by transmission electron microscopy. The BaSi2 film is found to consist of three layers with different microstructural characteristics, which is well explained by assuming two stages of film deposition. In the first stage, BaSi2 forms through the diffusion of Ba atoms from the deposited Ba-rich film to the Si substrate while in the second stage, the mutual diffusion of Ba and Si atoms in the film leads to BaSi2 formation. On the basis of the BaSi2 formation mechanism, two issues are addressed. One is the as-yet unclarified reason for epitaxial growth. It is found important to quickly form BaSi2 in the first stage for the epitaxial growth of upper layers. The other issue is the high oxygen concentration in BaSi2 films around the BaSi2-Si interface. Two routes of oxygen incorporation, i.e., oxidation of the Si substrate surface and initially deposited Ba-rich layer by the residual gas, are identified. On the basis of this knowledge, oxygen concentration is decreased by reducing the holding time of the substrate at high temperatures and by premelting of the source. In addition, X-ray diffraction results show that the decrease in oxygen concentration can lead to an increased proportion of a-axis-oriented grains.

  3. A stability investigation of two-dimensional surface waves on evaporating, isothermal or condensing liquid films - Part I, Thermal non-equilibrium effects on wave velocity

    International Nuclear Information System (INIS)

    Chunxi, L.; Xuemin, Y.

    2004-01-01

    The temporal stability equation of the two-dimensional traveling waves of evaporating or condensing liquid films falling down on an inclined wall is established based on the Prandtl boundary layer theory and complete boundary conditions. The model indicates that the wave velocity is related to the effects of evaporating, isothermal and condensing states, thermo-capillarity, Reynolds number, fluid property and inclined angle, and the effects of above factors are distinctly different under different Reynolds numbers. The theoretical studies show that evaporation process induces the wave velocity to increase slightly compared with the isothermal case, and condensation process induces the wave velocity to decrease slightly. Furthermore, the wave velocity decreases because of the effects of thermo-capillarity under evaporation and increases because of the effects of thermo-capillarity under condensation. The effects of thermal non-equilibrium conditions have relatively obvious effects under lower Reynolds numbers and little effects under higher Reynolds numbers

  4. Co-evaporation of fluoropolymer additives for improved thermal stability of organic semiconductors

    Science.gov (United States)

    Price, Jared S.; Wang, Baomin; Grede, Alex J.; Shen, Yufei; Giebink, Noel C.

    2017-08-01

    Reliability remains an ongoing challenge for organic light emitting diodes (OLEDs) as they expand in the marketplace. The ability to withstand operation and storage at elevated temperature is particularly important in this context, not only because of the inverse dependence of OLED lifetime on temperature, but also because high thermal stability is fundamentally important for high power/brightness operation as well as applications such as automotive lighting, where interior car temperatures often exceed the ambient by 50 °C or more. Here, we present a strategy to significantly increase the thermal stability of small molecule OLEDs by co-depositing an amorphous fluoropolymer, Teflon AF, to prevent catastrophic failure at elevated temperatures. Using this approach, we demonstrate that the thermal breakdown limit of common hole transport materials can be increased from typical temperatures of ˜100 °C to more than 200 °C while simultaneously improving their electrical transport properties. Similar thermal stability enhancements are demonstrated in simple bilayer OLEDs. These results point toward a general approach to engineer morphologically-stable organic electronic devices that are capable of operating or being stored in extreme thermal environments.

  5. Optimization of non-catalytic transesterification of tobacco (Nicotiana tabacum) seed oil using supercritical methanol to biodiesel production

    International Nuclear Information System (INIS)

    García-Martínez, Nuria; Andreo-Martínez, Pedro; Quesada-Medina, Joaquín; Pérez de los Ríos, Antonia Pérez; Chica, Antonio; Beneito-Ruiz, Rubén; Carratalá-Abril, Juan

    2017-01-01

    Highlights: • Biodiesel from tobacco oil was produced by non-catalytic supercritical methanolysis. • Maximum experimental yield of FAMEs (92.8%) was reached at 300 °C and 90 min. • Optimal conditions by RSM (303.4 °C and 90 min) predicted a maximum FAME yield of 91.1%. • Thermal decomposition of biodiesel was observed above 325 °C and 60 min of reaction. • Glycerol generated at 300 °C and 90 min was degraded and incorporated to the biodiesel. - Abstract: The biodiesel production from non-edible oils has high potential as renewable and ecological fuel. Few researches have been conducted to date on the production of biodiesel from tobacco (Nicotiana tabacum) seed oil. The aim of this study was to optimize the biodiesel production from this crude oil by non-catalytic supercritical methanolysis using response surface methodology (RSM). Triglyceride conversion, total and individual FAME yield, monoglyceride and diglyceride yield, and thermal decomposition degree of biodiesel were determined in the temperature and reaction time ranges of 250–350 °C (12–43 MPa) and 15–90 min, respectively, at a fixed methanol-to-oil molar ratio of 43:1. According to the RSM, the optimal conditions were 303.4 °C and 90 min, reaching a predicted maximum FAME yield of 91.1 ± 3.2 mol%. This maximum was very close to that obtained experimentally (92.8 ± 2.1 mol%) at 300 °C and 90 min. Decomposition of biodiesel became evident at 325 °C and 60 min of reaction due to the thermal instability of unsaturated methyl esters (methyl linoleate and oleate). The biodiesel obtained in the best experimental reaction conditions (300 °C and 90 min), where no thermal decomposition of FAMEs was observed, contained most of the byproduct glycerol generated, which was degraded and incorporated to the product. This biodiesel basically failed to meet the content of FAMEs as required by the standard EN 14214, the content of monoglycerides and total glycerol, and the acid value, being a

  6. Selective growth of Ge nanowires by low-temperature thermal evaporation.

    Science.gov (United States)

    Sutter, Eli; Ozturk, Birol; Sutter, Peter

    2008-10-29

    High-quality single-crystalline Ge nanowires with electrical properties comparable to those of bulk Ge have been synthesized by vapor-liquid-solid growth using Au growth seeds on SiO(2)/Si(100) substrates and evaporation from solid Ge powder in a low-temperature process at crucible temperatures down to 700 °C. High nanowire growth rates at these low source temperatures have been identified as being due to sublimation of GeO from substantial amounts of GeO(2) on the powder. The Ge nanowire synthesis from GeO is highly selective at our substrate temperatures (420-500 °C), i.e., occurs only on Au vapor-liquid-solid growth seeds. For growth of nanowires of 10-20 µm length on Au particles, an upper bound of 0.5 nm Ge deposition was determined in areas of bare SiO(2)/Si substrate without Au nanoparticles.

  7. Electrical and Optical Properties of GeSi−:H Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Thin a-GeSi1−:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As, and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the Ge0.5Si0.5:H thin films as pure, doped with 3.5% of Al (p-type and that doped with 3.5% As (n-type, were proposed.

  8. NOx formation and selective non-catalytic reduction (SNCR) in a fluidized bed combustor of biomass

    International Nuclear Information System (INIS)

    Mahmoudi, Shiva; Baeyens, Jan; Seville, Jonathan P.K.

    2010-01-01

    Caledonian Paper (CaPa) is a major paper mill, located in Ayr, Scotland. For its steam supply, it previously relied on the use of a Circulating Fluidized Bed Combustor (CFBC) of 58 MW th , burning coal, wood bark and wastewater treatment sludge. It currently uses a bubbling fluidized bed combustor (BFBC) of 102 MW th to generate steam at 99 bar, superheated to 465 o C. The boiler is followed by steam turbines and a 15 kg/s steam circuit into the mill. Whereas previously coal, wood bark and wastewater treatment sludge were used as fuel, currently only plantation wood (mainly spruce), demolition wood, wood bark and sludge are used. Since these biosolids contain nitrogen, fuel NO x is formed at the combustion temperature of 850-900 o C. NO x emissions (NO + NO 2 ) vary on average between 300 and 600 mg/Nm 3 (dry gas). The current emission standard is 350 mg/Nm 3 but will be reduced in the future to a maximum of 233 mg/Nm 3 for stand-alone biomass combustors of capacity between 50 and 300 MW th according to the EU LCP standards. NO x abatement is therefore necessary. In the present paper we firstly review the NO x formation mechanisms, proving that for applications of fluidized bed combustion, fuel NO x is the main consideration, and the contribution of thermal NO x to the emissions insignificant. We then assess the deNO x techniques presented in the literature, with an updated review and special focus upon the techniques that are applicable at CaPa. From these techniques, Selective Non-catalytic Reduction (SNCR) using ammonia or urea emerges as the most appropriate NO x abatement solution. Although SNCR deNO x is a selective reduction, the reactions of NO x reduction by NH 3 in the presence of oxygen, and the oxidation of NH 3 proceed competitively. Both reactions were therefore studied in a lab-scale reactor and the results were transformed into design equations starting from the respective reaction kinetics. An overall deNO x yield can then be predicted for any

  9. Preparation of InSe Thin Films by Thermal Evaporation Method and Their Characterization: Structural, Optical, and Thermoelectrical Properties

    Directory of Open Access Journals (Sweden)

    Sarita Boolchandani

    2018-01-01

    Full Text Available The indium selenium (InSe bilayer thin films of various thickness ratios, InxSe(1-x (x = 0.25, 0.50, 0.75, were deposited on a glass substrate keeping overall the same thickness of 2500 Ǻ using thermal evaporation method under high vacuum atmosphere. Electrical, optical, and structural properties of these bilayer thin films have been compared before and after thermal annealing at different temperatures. The structural and morphological characterization was done using XRD and SEM, respectively. The optical bandgap of these thin films has been calculated by Tauc’s relation that varies within the range of 1.99 to 2.05 eV. A simple low-cost thermoelectrical power measurement setup is designed which can measure the Seebeck coefficient “S” in the vacuum with temperature variation. The setup temperature variation is up to 70°C. This setup contains a Peltier device TEC1-12715 which is kept between two copper plates that act as a reference metal. Also, in the present work, the thermoelectric power of indium selenide (InSe and aluminum selenide (AlSe bilayer thin films prepared and annealed in the same way is calculated. The thermoelectric power has been measured by estimating the Seebeck coefficient for InSe and AlSe bilayer thin films. It was observed that the Seebeck coefficient is negative for InSe and AlSe thin films.

  10. A kinetic study on non-catalytic reactions in hydroprocessing Boscan crude oil

    Energy Technology Data Exchange (ETDEWEB)

    A. Marafi; E. Kam; A. Stanislaus [Kuwait Institute for Scientific Research, Safat (Kuwait). Petroleum Refining Department, Petroleum Research and Studies Center

    2008-08-15

    Non-catalytic hydrothermal cracking reactions are known to associate with catalytic hydrocracking reactions. In a recent study on hydroprocessing of Boscan crude over a specific catalyst system containing three distinct catalysts, it was found that hydrodesulfurization (HDS) and hydrodemetallation (HDM) reactions continued even when the catalyst is severely deactivated. Since the reactor was packed with considerable amount of inert material besides the three catalysts, it will be advantage to determine if the inert materials can also facilitate hydroprocessing reactions. A series of kinetic experiments for the inert particles was undertaken under different space velocity and temperature conditions. The extent of catalytic and non-catalytic hydroprocessing reactions was assessed. Through statistical analysis, the initial reaction rate constant, reaction order and activation energy for various hydroprocessing reactions were then determined. The absolute average deviations (AAD) of the kinetics values obtained for inert materials are less than 10%. 25 refs., 7 figs., 4 tabs.

  11. Thermal and Hydrologic Signatures of Soil Controls on Evaporation: A Combined Energy and Water Balance Approach with Implications for Remote Sensing of Evaporation

    Science.gov (United States)

    Salvucci, Guido D.

    2000-01-01

    The overall goal of this research is to examine the feasibility of applying a newly developed diagnostic model of soil water evaporation to large land areas using remotely sensed input parameters. The model estimates the rate of soil evaporation during periods when it is limited by the net transport resulting from competing effects of capillary rise and drainage. The critical soil hydraulic properties are implicitly estimated via the intensity and duration of the first stage (energy limited) evaporation, removing a major obstacle in the remote estimation of evaporation over large areas. This duration, or 'time to drying' (t(sub d)) is revealed through three signatures detectable in time series of remote sensing variables. The first is a break in soil albedo that occurs as a small vapor transmission zone develops near the surface. The second is a break in either surface to air temperature differences or in the diurnal surface temperature range, both of which indicate increased sensible heat flux (and/or storage) required to balance the decrease in latent heat flux. The third is a break in the temporal pattern of near surface soil moisture. Soil moisture tends to decrease rapidly during stage I drying (as water is removed from storage), and then become more or less constant during soil limited, or 'stage II' drying (as water is merely transmitted from deeper soil storage). The research tasks address: (1) improvements in model structure, including extensions to transpiration and aggregation over spatially variable soil and topographic landscape attributes; and (2) applications of the model using remotely sensed input parameters.

  12. Growth and Characterization of Indium Doped ZnO Nano wires Using Thermal Evaporation Method

    International Nuclear Information System (INIS)

    Abrar Ismardi; Dee, C.F.; Majlis, B.Y.

    2011-01-01

    Indium doped ZnO nano wires were grown on silicon substrate using vapor thermal deposition method without using any catalyst. Morphological structures were extensively investigated using field emission scanning electron microscopy (FESEM) and show that the nano wires have uniformly hexagonal nano structures with diameters less than 100 nm and lengths from one to a few microns. The sample was measured for elemental composition with energy dispersive X-ray (EDX) spectroscopy, Zn, In and O elements were found on the sample. XRD spectrum of indium doped ZnO nano wires revealed that the nano wires have a high crystalline structure. (author)

  13. Applications of Fuzzy adaptive PID control in the thermal power plant denitration liquid ammonia evaporation

    Directory of Open Access Journals (Sweden)

    Li Jing

    2016-01-01

    Full Text Available For the control of the liquid level of liquid ammonia in thermal power plant’s ammonia vaporization room, traditional PID controller parameter tuning is difficult to adapt to complex control systems, the setting of the traditional PID controller parameters is difficult to adapt to the complex control system. For the disadvantage of bad parameter setting, poor performance and so on the fuzzy adaptive PID control is proposed. Fuzzy adaptive PID control combines the advantages of traditional PID technology and fuzzy control. By using the fuzzy controller to intelligent control the object, the performance of the PID controller is further improved, and the control precision of the system is improved[1]. The simulation results show that the fuzzy adaptive PID controller not only has the advantages of high accuracy of PID controller, but also has the characteristics of fast and strong adaptability of fuzzy controller. It realizes the optimization of PID parameters which are in the optimal state, and the maximum increase production efficiency, so that are more suitable for nonlinear dynamic system.

  14. Optical and structural properties of CuSbS2 thin films grown by thermal evaporation method

    International Nuclear Information System (INIS)

    Rabhi, A.; Kanzari, M.; Rezig, B.

    2009-01-01

    Structural, optical and electrical properties of CuSbS 2 thin films grown by thermal evaporation have been studied relating the effects of substrate heating conditions of these properties. The CuSbS 2 thin films were carried out at substrate temperatures in the temperature range 100-200 deg. C . The structure and composition were characterized by XRD, SEM and EDX. X-ray diffraction revealed that the films are (111) oriented upon substrate temperature 170 deg. C and amorphous for the substrate temperatures below 170 deg. C . No secondary phases are observed for all the films. The optical absorption coefficients and band gaps of the films were estimated by optical transmission and reflection measurements at room temperature. Strong absorption coefficients in the range 10 5 -10 6 cm -1 at 500 nm were found. The direct gaps Eg lie between 0.91-1.89 eV range. It is observed that there is a decrease in optical band gap Eg with increasing the substrate temperature. Resistivity of 0.03-0.96 Ω cm, in dependence on substrate temperature was characterized. The all unheated films exhibit p-type conductivity. The characteristics reported here also offer perspective for CuSbS 2 as an absorber material in solar cells applications

  15. Effect of substrate temperature on the optical parameters of thermally evaporated Ge-Se-Te thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pankaj, E-mail: pks_phy@yahoo.co.i [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India); Katyal, S.C. [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India)

    2009-05-01

    Thin films of Ge{sub 10}Se{sub 90-x}Te{sub x} (x = 0, 10, 20, 30, 40, 50) glassy alloys were deposited at three substrate temperatures (303 K, 363 K and 423 K) using conventional thermal evaporation technique at base pressure of {approx} 10{sup -4} Pa. X-ray diffraction results show that films deposited at 303 K are of amorphous nature while films deposited at 363 K and 423 K are of polycrystalline nature. The optical parameters, refractive index and optical gap have been derived from the transmission spectra (using UV-Vis-NIR spectrophotometer) of the thin films in the spectral region 400-1500 nm. This has been observed that refractive index values remain almost constant while the optical gap is found to decrease considerably with the increase of substrate temperature. The decrease in optical gap is explained on the basis of change in nature of films, from amorphous to polycrystalline state, with the increase of substrate temperature. The optical gap has also been observed to decrease with the increase of Te content.

  16. A p-silicon nanowire/n-ZnO thin film heterojunction diode prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Hazra, Purnima; Jit, S.

    2014-01-01

    This paper represents the electrical and optical characteristics of a SiNW/ZnO heterojunction diode and subsequent studies on the photodetection properties of the diode in the ultraviolet (UV) wavelength region. In this work, silicon nanowire arrays were prepared on p-type (100)-oriented Si substrate by an electroless metal deposition and etching method with the help of ultrasonication. After that, catalyst-free deposition of zinc oxide (ZnO) nanowires on a silicon nanowire (SiNW) array substrate was done by utilizing a simple and cost-effective thermal evaporation technique without using a buffer layer. The SEM and XRD techniques are used to show the quality of the as-grown ZnO nanowire film. The junction properties of the diode are evaluated by measuring current—voltage and capacitance—voltage characteristics. The diode has a well-defined rectifying behavior with a rectification ratio of 190 at ±2 V, turn-on voltage of 0.5 V, and barrier height is 0.727 eV at room temperature under dark conditions. The photodetection parameters of the diode are investigated in the bias voltage range of ±2 V. The diode shows responsivity of 0.8 A/W at a bias voltage of 2 V under UV illumination (wavelength = 365 nm). The characteristics of the device indicate that it can be used for UV detection applications in nano-optoelectronic and photonic devices. (semiconductor devices)

  17. X-Ray diffraction analysis of thermally evaporated copper tin selenide thin films at different annealing temperature

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos; Zainal Abidin Talib; Wan Mahmood Mat Yunus; Josephine Liew Ying Chyi; Wilfred Sylvester Paulus

    2010-01-01

    Semiconductor thin films Copper Tin Selenide, Cu 2 SnSe 3 , a potential compound for semiconductor radiation detector or solar cell applications were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen, N 2 , for 2 hours in the temperature range from 100 to 500 degree Celsius. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from the Reitveld refinement show that the samples composed of Cu 2 SnSe 3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43 m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain. (author)

  18. Microstructural, nanomechanical, and microtribological properties of Pb thin films prepared by pulsed laser deposition and thermal evaporation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Broitman, Esteban, E-mail: esbro@ifm.liu.se [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping (Sweden); Flores-Ruiz, Francisco J. [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping, Sweden and Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Querétaro, Querétaro 76230 (Mexico); Di Giulio, Massimo [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce (Italy); Gontad, Francisco; Lorusso, Antonella; Perrone, Alessio [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce, Italy and INFN-Istituto Nazionale di Fisica Nucleare, 73100 Lecce (Italy)

    2016-03-15

    In this work, the authors compare the morphological, structural, nanomechanical, and microtribological properties of Pb films deposited by thermal evaporation (TE) and pulsed laser deposition (PLD) techniques onto Si (111) substrates. Films were investigated by scanning electron microscopy, surface probe microscopy, and x-ray diffraction in θ-2θ geometry to determine their morphology, root-mean-square (RMS) roughness, and microstructure, respectively. TE films showed a percolated morphology with densely packed fibrous grains while PLD films had a granular morphology with a columnar and tightly packed structure in accordance with the zone growth model of Thornton. Moreover, PLD films presented a more polycrystalline structure with respect to TE films, with RMS roughness of 14 and 10 nm, respectively. Hardness and elastic modulus vary from 2.1 to 0.8 GPa and from 14 to 10 GPa for PLD and TE films, respectively. A reciprocal friction test has shown that PLD films have lower friction coefficient and wear rate than TE films. Our study has demonstrated for first time that, at the microscale, Pb films do not show the same simple lubricious properties measured at the macroscale.

  19. Synthesis of ZnO Nanowires via Hotwire Thermal Evaporation of Brass (CuZn) Assisted by Vapor Phase Transport of Methanol

    OpenAIRE

    Tamil Many K. Thandavan; Siti Meriam Abdul Gani; Chiow San Wong; Roslan Md Nor

    2014-01-01

    Zinc oxide (ZnO) nanowires (NWs) were synthesized using vapor phase transport (VPT) and thermal evaporation of Zn from CuZn. Time dependence of ZnO NWs growth was investigated for 5, 10, 15, 20, 25, and 30 minutes. Significant changes were observed from the field electron scanning electron microscopy (FESEM) images as well as from the X-ray diffraction (XRD) profile. The photoluminescence (PL) profile was attributed to the contribution of oxygen vacancy, zinc interstitials, and hydrogen defec...

  20. Numerical simulation of urea based selective non-catalytic reduction deNOx process for industrial applications

    International Nuclear Information System (INIS)

    Baleta, Jakov; Mikulčić, Hrvoje; Vujanović, Milan; Petranović, Zvonimir; Duić, Neven

    2016-01-01

    Highlights: • SNCR is a simple method for the NOx reduction from large industrial facilities. • Capabilities of the developed mathematical framework for SNCR simulation were shown. • Model was used on the geometry of experimental reactor and municipal incinerator. • Results indicate suitability of the developed model for real industrial cases. - Abstract: Industrial processes emit large amounts of diverse pollutants into the atmosphere, among which NOx takes a significant portion. Selective non-catalytic reduction (SNCR) is a relatively simple method for the NOx reduction in large industrial facilities such as power plants, cement plants and waste incinerator plants. It consists of injecting the urea-water solution in the hot flue gas stream and its reaction with the NOx. During this process flue gas enthalpy is used for the urea-water droplet heating and for the evaporation of water content. After water evaporates, thermolysis of urea occurs, during which ammonia, a known NO_x reductant, and isocyanic acid are generated. In order to cope with the ever stringent environmental norms, equipment manufacturers need to develop energy efficient products that are at the same time benign to environment. This is becoming increasingly complicated and costly, and one way to reduce production costs together with the maintaining the same competitiveness level is to employ computational fluid dynamics (CFD) as a tool, in a process today commonly known under the term “virtual prototyping”. The aim of this paper is to show capabilities of the developed mathematical framework implemented in the commercial CFD code AVL FIRE®, to simulate physical processes of all relevant phenomena occurring during the SNCR process. First, mathematical models for description of SNCR process are presented and afterwards, models are used on the 3D geometry of an industrial reactor and a real industrial case to predict SNCR efficiency, temperature and velocity field. Influence of the main

  1. Enhanced Charge Extraction of Li-Doped TiO2 for Efficient Thermal-Evaporated Sb2S3 Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Chunfeng Lan

    2018-02-01

    Full Text Available We provided a new method to improve the efficiency of Sb2S3 thin film solar cells. The TiO2 electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb2S3 solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO2 films. Compared with the undoped TiO2, Li-doped mesoporous TiO2 dramatically improved the photo-voltaic performance of the thermal-evaporated Sb2S3 thin film solar cells, with the average power conversion efficiency (PCE increasing from 1.79% to 4.03%, as well as the improved open-voltage (Voc, short-circuit current (Jsc and fill factors. The best device based on Li-doped TiO2 achieved a power conversion efficiency up to 4.42% as well as a Voc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb2S3 solar cells. This study showed that Li-doping on TiO2 can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb2S3-based solar cells.

  2. Enhanced Charge Extraction of Li-Doped TiO2 for Efficient Thermal-Evaporated Sb2S3 Thin Film Solar Cells

    Science.gov (United States)

    Lan, Chunfeng; Luo, Jingting; Lan, Huabin; Fan, Bo; Peng, Huanxin; Zhao, Jun; Sun, Huibin; Zheng, Zhuanghao; Liang, Guangxing; Fan, Ping

    2018-01-01

    We provided a new method to improve the efficiency of Sb2S3 thin film solar cells. The TiO2 electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb2S3 solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO2 films. Compared with the undoped TiO2, Li-doped mesoporous TiO2 dramatically improved the photo-voltaic performance of the thermal-evaporated Sb2S3 thin film solar cells, with the average power conversion efficiency (PCE) increasing from 1.79% to 4.03%, as well as the improved open-voltage (Voc), short-circuit current (Jsc) and fill factors. The best device based on Li-doped TiO2 achieved a power conversion efficiency up to 4.42% as well as a Voc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb2S3 solar cells. This study showed that Li-doping on TiO2 can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb2S3-based solar cells. PMID:29495612

  3. Enhanced Charge Extraction of Li-Doped TiO₂ for Efficient Thermal-Evaporated Sb₂S₃ Thin Film Solar Cells.

    Science.gov (United States)

    Lan, Chunfeng; Luo, Jingting; Lan, Huabin; Fan, Bo; Peng, Huanxin; Zhao, Jun; Sun, Huibin; Zheng, Zhuanghao; Liang, Guangxing; Fan, Ping

    2018-02-28

    We provided a new method to improve the efficiency of Sb₂S₃ thin film solar cells. The TiO₂ electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb₂S₃ solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO₂ films. Compared with the undoped TiO₂, Li-doped mesoporous TiO₂ dramatically improved the photo-voltaic performance of the thermal-evaporated Sb₂S₃ thin film solar cells, with the average power conversion efficiency ( PCE ) increasing from 1.79% to 4.03%, as well as the improved open-voltage ( V oc ), short-circuit current ( J sc ) and fill factors. The best device based on Li-doped TiO₂ achieved a power conversion efficiency up to 4.42% as well as a V oc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb₂S₃ solar cells. This study showed that Li-doping on TiO₂ can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb₂S₃-based solar cells.

  4. Solid-Liquid Interface Thermal Resistance Affects the Evaporation Rate of Droplets from a Surface: A Study of Perfluorohexane on Chromium Using Molecular Dynamics and Continuum Theory.

    Science.gov (United States)

    Han, Haoxue; Schlawitschek, Christiane; Katyal, Naman; Stephan, Peter; Gambaryan-Roisman, Tatiana; Leroy, Frédéric; Müller-Plathe, Florian

    2017-05-30

    We study the role of solid-liquid interface thermal resistance (Kapitza resistance) on the evaporation rate of droplets on a heated surface by using a multiscale combination of molecular dynamics (MD) simulations and analytical continuum theory. We parametrize the nonbonded interaction potential between perfluorohexane (C 6 F 14 ) and a face-centered-cubic solid surface to reproduce the experimental wetting behavior of C 6 F 14 on black chromium through the solid-liquid work of adhesion (quantity directly related to the wetting angle). The thermal conductances between C 6 F 14 and (100) and (111) solid substrates are evaluated by a nonequilibrium molecular dynamics approach for a liquid pressure lower than 2 MPa. Finally, we examine the influence of the Kapitza resistance on evaporation of droplets in the vicinity of a three-phase contact line with continuum theory, where the thermal resistance of liquid layer is comparable with the Kapitza resistance. We determine the thermodynamic conditions under which the Kapitza resistance plays an important role in correctly predicting the evaporation heat flux.

  5. Waste Heat Recovery and Recycling in Thermal Separation Processes: Distillation, Multi-Effect Evaporation (MEE) and Crystallization Processes

    Energy Technology Data Exchange (ETDEWEB)

    Emmanuel A. Dada; Chandrakant B. Panchal; Luke K. Achenie; Aaron Reichl; Chris C. Thomas

    2012-12-03

    Evaporation and crystallization are key thermal separation processes for concentrating and purifying inorganic and organic products with energy consumption over 1,000 trillion Btu/yr. This project focused on a challenging task of recovering low-temperature latent heat that can have a paradigm shift in the way thermal process units will be designed and operated to achieve high-energy efficiency and significantly reduce the carbon footprint as well as water footprint. Moreover, this project has evaluated the technical merits of waste-heat powered thermal heat pumps for recovery of latent heat from distillation, multi-effect evaporation (MEE), and crystallization processes and recycling into the process. The Project Team has estimated the potential energy, economics and environmental benefits with the focus on reduction in CO2 emissions that can be realized by 2020, assuming successful development and commercialization of the technology being developed. Specifically, with aggressive industry-wide applications of heat recovery and recycling with absorption heat pumps, energy savings of about 26.7 trillion Btu/yr have been estimated for distillation process. The direct environmental benefits of this project are the reduced emissions of combustible products. The estimated major reduction in environmental pollutants in the distillation processes is in CO2 emission equivalent to 3.5 billion lbs/year. Energy consumption associated with water supply and treatments can vary between 1,900 kWh and 23,700 kWh per million-gallon water depending on sources of natural waters [US DOE, 2006]. Successful implementation of this technology would significantly reduce the demand for cooling-tower waters, and thereby the use and discharge of water treatment chemicals. The Project Team has also identified and characterized working fluid pairs for the moderate-temperature heat pump. For an MEE process, the two promising fluids are LiNO3+KNO3+NANO3 (53:28:19 ) and LiNO3+KNO3+NANO2

  6. Development of a Global Evaporative Stress Index Based on Thermal and Microwave LST towards Improved Monitoring of Agricultural Drought

    Science.gov (United States)

    Hain, C.; Anderson, M. C.; Otkin, J.; Holmes, T. R.; Gao, F.

    2017-12-01

    This presentation will describe the development of a global agricultural monitoring tool, with a focus on providing early warning of developing vegetation stress for agricultural decision-makers and stakeholders at relatively high spatial resolution (5-km). The tool is based on remotely sensed estimates of evapotranspiration, retrieved via energy balance principals using observations of land surface temperature. The Evaporative Stress Index (ESI) represents anomalies in the ratio of actual-to-potential ET generated with the ALEXI surface energy balance model. The LST inputs to ESI have been shown to provide early warning information about the development of vegetation stress with stress-elevated canopy temperatures observed well before a decrease in greenness is detected in remotely sensed vegetation indices. As a diagnostic indicator of actual ET, the ESI requires no information regarding antecedent precipitation or soil moisture storage capacity - the current available moisture to vegetation is deduced directly from the remotely sensed LST signal. This signal also inherently accounts for both precipitation and non-precipitation related inputs/sinks to the plant-available soil moisture pool (e.g., irrigation) which can modify crop response to rainfall anomalies. Independence from precipitation data is a benefit for global agricultural monitoring applications due to sparseness in existing ground-based precipitation networks, and time delays in public reporting. Several enhancements to the current ESI framework will be addressed as requested from project stakeholders: (a) integration of "all-sky" MW Ka-band LST retrievals to augment "clear-sky" thermal-only ESI in persistently cloudy regions; (b) operational production of ESI Rapid Change Indices which provide important early warning information related to onset of actual vegetation stress; and (c) assessment of ESI as a predictor of global yield anomalies; initial studies have shown the ability of intra

  7. Streamer Evaporation

    Science.gov (United States)

    Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.

    1998-01-01

    Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.

  8. Production of Sn/SnO2/MWCNT composites by plasma oxidation after thermal evaporation from pure Sn targets onto buckypapers.

    Science.gov (United States)

    Alaf, M; Gultekin, D; Akbulut, H

    2012-12-01

    In this study, tin/tinoxide/multi oxide/multi walled carbon nano tube (Sn/SnO2/MWCNT) composites were produced by thermal evaporation and then subsequent plasma oxidation. Buckypapers having controlled porosity were prepared by vacuum filtration from functionalized MWCNTs. Pure metallic tin was thermally evaporated on the buckypapers in argon atmosphere with different thicknesses. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypaper to form a nanocomposite. The tin/MWCNT composites were subjected to plasma oxidation process at oxygen/argon gas mixture. Three different plasma oxidation times (30, 45 and 60 minutes) were used to investigate oxidation and physical and microstructural properties. The effect of coating thickness and oxidation time was investigated to understand the effect of process parameters on the Sn and SnO2 phases after plasma oxidation. Quantitative phase analysis was performed in order to determine the relative phase amounts. The structural properties were studied by field-emission gun scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD).

  9. Self-catalyst growth of novel GaN nanowire flowers on Si (111) using thermal evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Saron, K.M.A., E-mail: kamalmohammedabdalla@yahoo.com [Nano-Optoelectronics Research and Technology Laboratory (NOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Hashim, M.R., E-mail: roslan@usm.my [Nano-Optoelectronics Research and Technology Laboratory (NOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2013-05-15

    We investigated the effect of substrate temperature on nanowire (NW) flower GaN epitaxial layers grown on catalyst-free Si (111) through physical vapor deposition via the thermal evaporation of GaN powder at 1150 °C in the absence of NH{sub 3} gas. The NW flowers were grown at various substrate temperatures from 1000 °C to 1100 °C for 60 min in N{sub 2} ambient. The surface morphology as well as the structural and optical properties of GaN NW flowers were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence (PL). The results showed that the increase in substrate temperature resulted in a variation in crystal quality and surface morphology. SEM showed that the substrate temperature has a stronger effect on NW density and growth rate with respect to time. The average length of GaN flowers is estimated to be longer than 300 μm after 1 h at 1100 °C, which corresponds to a fast growth rate of more than 200 μm h{sup −1} at all substrate temperatures. The PL measurements showed strong near-band-edge (NBE) emission with a weak deep level emission. The green-yellow emission (GYE) can be attributed to N vacancies or to the V{sub Ga}–O{sub N}-complexes. The NBE peak exhibited a redshift with increasing substrate temperature, which results from the increase in strain level. The growth mechanism of the polycrystalline GaN NWs was also discussed. - Highlights: ► GaN nanowired flowers were grown on free-catalysts Si (111) using PVD. ► A higher temperature, higher uniformity, larger lengths and diameters of the NW flowers. ► As substrate temperature increases the diameters and growth rate of NWs increases. ► A lower temperature resulted in a high density and good crystal quality of GaN NWs. ► The increase in substrate temperature increased the redshift in UV band emission.

  10. Self-catalyst growth of novel GaN nanowire flowers on Si (111) using thermal evaporation technique

    International Nuclear Information System (INIS)

    Saron, K.M.A.; Hashim, M.R.

    2013-01-01

    We investigated the effect of substrate temperature on nanowire (NW) flower GaN epitaxial layers grown on catalyst-free Si (111) through physical vapor deposition via the thermal evaporation of GaN powder at 1150 °C in the absence of NH 3 gas. The NW flowers were grown at various substrate temperatures from 1000 °C to 1100 °C for 60 min in N 2 ambient. The surface morphology as well as the structural and optical properties of GaN NW flowers were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence (PL). The results showed that the increase in substrate temperature resulted in a variation in crystal quality and surface morphology. SEM showed that the substrate temperature has a stronger effect on NW density and growth rate with respect to time. The average length of GaN flowers is estimated to be longer than 300 μm after 1 h at 1100 °C, which corresponds to a fast growth rate of more than 200 μm h −1 at all substrate temperatures. The PL measurements showed strong near-band-edge (NBE) emission with a weak deep level emission. The green-yellow emission (GYE) can be attributed to N vacancies or to the V Ga –O N -complexes. The NBE peak exhibited a redshift with increasing substrate temperature, which results from the increase in strain level. The growth mechanism of the polycrystalline GaN NWs was also discussed. - Highlights: ► GaN nanowired flowers were grown on free-catalysts Si (111) using PVD. ► A higher temperature, higher uniformity, larger lengths and diameters of the NW flowers. ► As substrate temperature increases the diameters and growth rate of NWs increases. ► A lower temperature resulted in a high density and good crystal quality of GaN NWs. ► The increase in substrate temperature increased the redshift in UV band emission

  11. A comparative study of the electrical properties of Pd/ZnO Schottky contacts fabricated using electron beam deposition and resistive/thermal evaporation techniques

    International Nuclear Information System (INIS)

    Mtangi, W.; Auret, F. D.; Janse van Rensburg, P. J.; Coelho, S. M. M.; Legodi, M. J.; Nel, J. M.; Meyer, W. E.; Chawanda, A.

    2011-01-01

    A systematic investigation to check the quality of Pd Schottky contacts deposited on ZnO has been performed on electron beam (e-beam) deposited and resistively/thermally evaporated samples using current-voltage, IV, and conventional deep level transient spectroscopy (DLTS) measurements. Room temperature IV measurements reveal the dominance of pure thermionic emission on the resistively evaporated contacts, while the e-beam deposited contacts show the dominance of generation recombination at low voltages, -10 A at a reverse voltage of 1.0 V whereas the e-beam deposited contacts have reverse currents of the order of 10 -6 A at 1.0 V. Average ideality factors have been determined as (1.43 ± 0.01) and (1.66 ± 0.02) for the resistively evaporated contacts and e-beam deposited contacts, respectively. The IV barrier heights have been calculated as (0.721 ± 0.002) eV and (0.624 ± 0.005) eV for the resistively evaporated and e-beam deposited contacts, respectively. Conventional DLTS measurements reveal the presence of three prominent defects in both the resistive and e-beam contacts. Two extra peaks with energy levels of 0.60 and 0.81 eV below the conduction band minimum have been observed in the e-beam deposited contacts. These have been explained as contributing to the generation recombination current that dominates at low voltages and high leakage currents. Based on the reverse current at 1.0 V, the degree of rectification, the dominant current transport mechanism and the observed defects, we conclude that the resistive evaporation technique yields better quality Schottky contacts for use in solar cells and ultraviolet detectors compared to the e-beam deposition technique. The 0.60 eV has been identified as possibly related to the unoccupied level for the doubly charged oxygen vacancy, V o 2+ .

  12. Structural specifics of the condensate prepared by thermal evaporation of alloys of As2S3-Yb systems

    International Nuclear Information System (INIS)

    Ehfendiev, Eh.G.; Mamedov, A.I.; Il'yasov, T.M.; Rustamov, P.G.

    1987-01-01

    The problem aimed at preparation of the films of As 2 S 3 -Yb system, at studying their substructure depending on condensation conditions and defining noncrystallinity region of this system in the film state, is formulated. It is shown that in representative samples of As 2 S 3 -Yb system the vitrification region is extended up to 7 at.% Yb, in the films noncrystallinity region is extended up to 30 at.% Yb. With up to 30 at.% increase of ytterbium amount in initial alloys a tendency to crystallization in amorphous condensate structure is noticed. In evaporation of As 2 S 3 + 40 at.% Yb and As 2 S 3 + 50 at.% Yb, unknown in the film state YbAs 2 S 4 , Yb 3 As 4 S 9 and YbAs 4 S 7 phases are prepared, and the latter is formed in case of As 2 S 3 + 50 at.% Yb alloy at small evaporation rates (∼10 A/s). Substructure of As 2 S 3 + 50 at.% Yb alloy prepared condensate is more dependent on evaporation rate than in evaporation of As 2 S 3 + 40 at.% Yb alloy. In this case, evaporation rates being ∼ 100 A/s, the condensate has a polycrystal structure, and at small rates of ∼ 10 A/c, condensate structure is primarily blocked

  13. The secret life of kinases: insights into non-catalytic signalling functions from pseudokinases.

    Science.gov (United States)

    Jacobsen, Annette V; Murphy, James M

    2017-06-15

    Over the past decade, our understanding of the mechanisms by which pseudokinases, which comprise ∼10% of the human and mouse kinomes, mediate signal transduction has advanced rapidly with increasing structural, biochemical, cellular and genetic studies. Pseudokinases are the catalytically defective counterparts of conventional, active protein kinases and have been attributed functions as protein interaction domains acting variously as allosteric modulators of conventional protein kinases and other enzymes, as regulators of protein trafficking or localisation, as hubs to nucleate assembly of signalling complexes, and as transmembrane effectors of such functions. Here, by categorising mammalian pseudokinases based on their known functions, we illustrate the mechanistic diversity among these proteins, which can be viewed as a window into understanding the non-catalytic functions that can be exerted by conventional protein kinases. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  14. Biodiesel production through non-catalytic supercritical transesterification: current state and perspectives

    Directory of Open Access Journals (Sweden)

    C. da Silva

    2014-06-01

    Full Text Available The inconveniences of the conventional method for biodiesel production by alkaline catalysis suggests research towards alternative methods, with the non-catalytic transesterification using an alcohol at supercritical conditions proposed as a promising technique for biodiesel production. The so-called supercritical method (SCM has powerful advantages over conventional techniques, such as fast reaction rates, feedstock flexibility, production efficiency and environmentally friendly benefits. However, application of this methodology has some limitations, like operating conditions (elevated temperature and pressure and higher amounts of alcohol, which result in high energy costs and degradation of the products generated. In this review paper the state of the art in relation to the use of the SCM for biodiesel production is reported and discussed, describing the characteristics of the method, the influence of operational parameters on the ester yield, patents available in the field and the perspectives for application of the technique.

  15. Calculation of Thermal Mode of Flat Irradiated Ceramic Mass Sample’ while Evaporating Moisture from Heated-up Surface

    Directory of Open Access Journals (Sweden)

    S. N. Osipov

    2004-01-01

    Full Text Available The solution of a differential heat conduction equation is given in view of cooling effect of moisture evaporation from a heated surface. In this case heating heat flow is diminishing in time exponentially. The most typical nomographic temperature and temperature gradient charts of heated surface and mean temperature of a plate are presented in the paper.

  16. Effect of argon gas flow rate on properties of film electrodes prepared by thermal vacuum evaporation from synthesized Cu{sub 2}SnSe{sub 3} source

    Energy Technology Data Exchange (ETDEWEB)

    Sabli, Nordin; Talib, Zainal Abidin; Yunus, Wan Mahmood Mat [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang (Malaysia); Zainal, Zulkarnain [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang (Malaysia); Hilal, Hikmat S. [SSERL, Department of Chemistry An-Najah N. University, PO Box 7, Nablus, West Bank (Country Unknown); Fujii, Masatoshi [Department of Molecular Science, School of Medicine, Shimane University, Izumo, Shimane, 693-8501 (Japan)

    2014-03-05

    This work describes a new technique to enhance photoresponse of metal chalcogenide-based semiconductor film electrodes deposited by thermal vacuum evaporation under argon gas flow from synthesized Cu{sub 2}SnSe{sub 3} sources. SnSe formation with Cu-doped was obtained under higher argon gas flow rate (V{sub A} = 25 cm{sup 3}/min). Higher value of photoresponse was observed for films deposited under V{sub A} = 25 cm{sup 3}/min which was 9.1%. This finding indicates that Cu atoms inside the SnSe film were important to increase carrier concentrations that promote higher photoresponse.

  17. Vacuum-thermal-evaporation: the route for roll-to-roll production of large-area organic electronic circuits

    International Nuclear Information System (INIS)

    Taylor, D M

    2015-01-01

    Surprisingly little consideration is apparently being given to vacuum-evaporation as the route for the roll-to-roll (R2R) production of large-area organic electronic circuits. While considerable progress has been made by combining silicon lithographic approaches with solution processing, it is not obvious that these will be compatible with a low-cost, high-speed R2R process. Most efforts at achieving this ambition are directed at conventional solution printing approaches such as inkjet and gravure. This is surprising considering that vacuum-evaporation of organic semiconductors (OSCs) is already used commercially in the production of organic light emitting diode displays. Beginning from a discussion of the materials and geometrical parameters determining transistor performance and drawing on results from numerous publications, this review makes a case for vacuum-evaporation as an enabler of R2R organic circuit production. The potential of the vacuum route is benchmarked against solution approaches and found to be highly competitive. For example, evaporated small molecules tend to have higher mobility than printed OSCs. High resolution metal patterning on plastic films is already a low-cost commercial process for high-volume packaging applications. Similarly, solvent-free flash-evaporation and polymerization of thin films on plastic substrates is also a high-volume commercial process and has been shown capable of producing robust gate dielectrics. Reports of basic logic circuit elements produced in a vacuum R2R environment are reviewed and shown to be superior to all-solution printing approaches. Finally, the main issues that need to be resolved in order to fully develop the vacuum route to R2R circuit production are highlighted. (paper)

  18. Standard test method for determination of uranium or plutonium isotopic composition or concentration by the total evaporation method using a thermal ionization mass spectrometer

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This method describes the determination of the isotopic composition and/or the concentration of uranium and plutonium as nitrate solutions by the thermal ionization mass spectrometric (TIMS) total evaporation method. Purified uranium or plutonium nitrate solutions are loaded onto a degassed metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the filament(s). The ion beams are continually measured until the sample is exhausted. The measured ion currents are integrated over the course of the run, and normalized to a reference isotope ion current to yield isotopic ratios. 1.2 In principle, the total evaporation method should yield isotopic ratios that do not require mass bias correction. In practice, some samples may require this bias correction. When compared to the conventional TIMS method, the total evaporation method is approximately two times faster, improves precision from two to four fold, and utilizes smaller sample sizes. 1.3 The tot...

  19. Structural, optical and electrical properties of CuIn{sub 5}S{sub 8} thin films grown by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Gannouni, M., E-mail: gm_mounir@yahoo.fr [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs -ENIT BP 37, Le belvedere 1002-Tunis (Tunisia); Kanzari, M. [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs -ENIT BP 37, Le belvedere 1002-Tunis (Tunisia)

    2011-05-19

    Highlights: > In this work, thin films of CuIn{sub 5}S{sub 8} were successfully deposited onto glass substrates by thermal evaporation and annealed in air. > Post-depositional annealing effects on structural, optical and electrical properties of thermal evaporated CuIn{sub 5}S{sub 8} thin films were studied. > The results reported in this work make this material attractive as an absorber material in solar cells applications. - Abstract: Stoichiometric compound of copper indium sulfur (CuIn{sub 5}S{sub 8}) was synthesized by direct reaction of high purity elemental copper, indium and sulfur in an evacuated quartz tube. The phase structure of the synthesized material revealed the cubic spinel structure. The lattice parameter (a) of single crystals was calculated to be 10.667 A. Thin films of CuIn{sub 5}S{sub 8} were deposited onto glass substrates under the pressure of 10{sup -6} Torr using thermal evaporation technique. CuIn{sub 5}S{sub 8} thin films were then thermally annealed in air from 100 to 300 deg. C for 2 h. The effects of thermal annealing on their physico-chemical properties were investigated using X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), optical transmission and hot probe method. XRD studies of CuIn{sub 5}S{sub 8} thin films showed that as-deposited films were amorphous in nature and transformed into polycrystalline spinel structure with strong preferred orientation along the (3 1 1) plane after the annealing at 200 deg. C. The composition is greatly affected by thermal treatment. From the optical transmission and reflection, an important absorption coefficient exceeds 10{sup 4} cm{sup -1} was found. As increasing the annealing temperature, the optical energy band gap decreases from 1.83 eV for the as-deposited films to 1.43 eV for the annealed films at 300 deg. C. It was found that CuIn{sub 5}S{sub 8} thin film is an n-type semiconductor at 300 deg. C.

  20. Rule-based Mamdani-type fuzzy modelling of thermal performance of fintube evaporator under frost conditions

    Directory of Open Access Journals (Sweden)

    Ozen Dilek Nur

    2016-01-01

    Full Text Available Frost formation brings about insulating effects over the surface of a heat exchanger and thereby deteriorating total heat transfer of the heat exchanger. In this study, a fin-tube evaporator is modeled by making use of Rule-based Mamdani-Type Fuzzy (RBMTF logic where total heat transfer, air inlet temperature of 2 °C to 7 °C and four different fluid speed groups (ua1=1; 1.44; 1.88 m s-1, ua2=2.32; 2.76 m s-1, ua3=3.2; 3.64 m s-1, ua4=4.08; 4.52; 4.96 m s-1 for the evaporator were taken into consideration. In the developed RBMTF system, outlet parameter UA was determined using inlet parameters Ta and ua. The RBMTF was trained and tested by using MATLAB® fuzzy logic toolbox. R2 (% for the training data and test data were found to be 99.91%. With this study, it has been shown that RBMTF model can be reliably used in determination of a total heat transfer of a fin-tube evaporator.

  1. In{sub 6}Se{sub 7} thin films by heating thermally evaporated indium and chemical bath deposited selenium multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ornelas, R.E.; Avellaneda, D. [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Shaji, S. [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Universidad Autonoma de Nuevo Leon-CIIDIT, Apodaca, N.L (Mexico); Castillo, G.A.; Roy, T.K. Das [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Universidad Autonoma de Nuevo Leon-CIIDIT, Apodaca, N.L (Mexico)

    2012-05-15

    Indium selenide (In{sub 6}Se{sub 7}) thin films were prepared via selenization of thermally evaporated indium thin films by dipping in sodium selenosulphate solution followed by annealing in nitrogen atmosphere. First, indium was thermally evaporated on glass substrate. Then, the indium coated glass substrates were dipped in a solution containing 80 ml 0.125 M sodium selenosulphate and 1.5 ml dilute acetic acid (25%) for 5 min. Glass/In-Se layers were annealed at 200-400 Degree-Sign C in nitrogen atmosphere (0.1 Torr) for 30 min. X-ray diffraction studies showed the formation of monoclinic In{sub 6}Se{sub 7}. Morphology of the thin films formed at different conditions was analyzed using Scanning electron microscopy. The elemental analysis was done using Energy dispersive X-ray detection. Electrical conductivity under dark and illumination conditions was evaluated. Optical band gap was computed using transmittance and reflectance spectra. The band gap value was in the range 1.8-2.6 eV corresponding to a direct allowed transition. We studied the effect of indium layer thickness and selenium deposition time on the structure, electrical and optical properties of In{sub 6}Se{sub 7} thin films.

  2. Environmental and economic evaluation of selective non-catalytic reduction of nitrogen oxides

    Science.gov (United States)

    Parchevskii, V. M.; Shchederkina, T. E.; Proshina, A. O.

    2017-11-01

    There are two groups of atmosphere protecting measures: technology (primary) and treatment (secondary). When burning high-calorie low-volatile brands of coals in the furnaces with liquid slag removal to achieve emission standards required joint use of these two methods, for example, staged combustion and selective non-catalytic reduction recovery (SNCR). For the economically intelligent combination of these two methods it is necessary to have information not only about the environmental performance of each method, but also the operating costs per unit of reduced emission. The authors of this report are made an environmental-economic analysis of SNCR on boiler Π-50P Kashirskaya power station. The obtained results about the dependence of costs from the load of the boiler and the mass emissions of nitrogen oxides then approximates into empirical formulas, is named as environmental and economic characteristics, which is suitable for downloading into controllers and other control devices for subsequent implementation of optimal control of emissions to ensure compliance with environmental regulations at the lowest cost at any load of the boiler.

  3. Thickness-controlled direct growth of nanographene and nanographite film on non-catalytic substrates

    Science.gov (United States)

    Du, Lei; Yang, Liu; Hu, Zhiting; Zhang, Jiazhen; Huang, Chunlai; Sun, Liaoxin; Wang, Lin; Wei, Dacheng; Chen, Gang; Lu, Wei

    2018-05-01

    Metal-catalyzed chemical vapor deposition (CVD) has been broadly employed for large-scale production of high-quality graphene. However, a following transfer process to targeted substrates is needed, which is incompatible with current silicon technology. We here report a new CVD approach to form nanographene and nanographite films with accurate thickness control directly on non-catalytic substrates such as silicon dioxide and quartz at 800 °C. The growth time is as short as a few seconds. The approach includes using 9-bis(diethylamino)silylanthracene as the carbon source and an atomic layer deposition (ALD) controlling system. The structure of the formed nanographene and nanographite films were characterized using atomic force microscopy, high resolution transmission electron microscopy, Raman scattering, and x-ray photoemission spectroscopy. The nanographite film exhibits a transmittance higher than 80% at 550 nm and a sheet electrical resistance of 2000 ohms per square at room temperature. A negative temperature-dependence of the resistance of the nanographite film is also observed. Moreover, the thickness of the films can be precisely controlled via the deposition cycles using an ALD system, which promotes great application potential for optoelectronic and thermoelectronic-devices.

  4. A non-catalytic histidine residue influences the function of the metalloprotease of Listeria monocytogenes.

    Science.gov (United States)

    Forster, Brian M; Bitar, Alan Pavinski; Marquis, Hélène

    2014-01-01

    Mpl, a thermolysin-like metalloprotease, and PC-PLC, a phospholipase C, are synthesized as proenzymes by the intracellular bacterial pathogen Listeria monocytogenes. During intracellular growth, L. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to Mpl autolysis and Mpl-mediated cleavage of the PC-PLC N-terminal propeptide. Mpl maturation also leads to the secretion of both Mpl and PC-PLC across the bacterial cell wall. Previously, we identified negatively charged and uncharged amino acid residues within the N terminus of the PC-PLC propeptide that influence the ability of Mpl to mediate the maturation of PC-PLC, suggesting that these residues promote the interaction of the PC-PLC propeptide with Mpl. In the present study, we identified a non-catalytic histidine residue (H226) that influences Mpl secretion across the cell wall and its ability to process PC-PLC. Our results suggest that a positive charge at position 226 is required for Mpl functions other than autolysis. Based on the charge requirement at this position, we hypothesize that this residue contributes to the interaction of Mpl with the PC-PLC propeptide.

  5. Catalytic gasification in fluidized bed, of orange waste. Comparison with non catalytic gasification

    International Nuclear Information System (INIS)

    Aguiar Trujillo, Leonardo; Marquez Montesinos, Francisco; Ramos Robaina, Boris A.; Guerra Reyes, Yanet; Arauzo Perez, Jesus; Gonzalo Callejo, Alberto; Sanchez Cebrian, Jose L

    2011-01-01

    The industry processing of the orange, generates high volumes of solid waste. This waste has been used as complement in the animal feeding, in biochemical processes; but their energy use has not been valued by means of the gasification process. They were carried out gasification studies with air in catalytic fluidized bed (using dolomite and olivine as catalysts in a secondary reactor, also varying the temperature of the secondary reactor and the catalyst mass), of the solid waste of orange and the results are compared with those obtained in the gasification with non catalytic air. In the processes we use a design of complete factorial experiment of 2k, valuing the influence of the independent variables and their interactions in the answers, using the software Design-Expert version 7 and a grade of significance of 95 %. The results demonstrate the qualities of the solid waste of orange in the energy use by means of the gasification process for the treatment of these residuals, obtaining a gas of low caloric value. The use of catalysts also diminishes the yield of tars obtained in the gasification process, being more active the dolomite that the olivine in this process. (author)

  6. Luminescence of one dimensional ZnO, GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanostructure through thermal evaporation of Zn and Ge powder mixture

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn; Kien, Vu Trung; Tam, Phuong Dinh; Huy, Pham Thanh

    2016-07-15

    Graphical abstract: - Highlights: • ZnO and GeO{sub 2}–ZnGeO{sub 4} nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture. • Morphology of specimens were observed to have a nanowire structure to rod-like morphology. • Strong NBE emission band with suppressed visible green emission band were observed on the dominant ZnO nanowires. • Strong emission of ∼530 nm were observed on the GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires. - Abstract: This paper reports the first attempt for fabrication of thermal evaporated Zn–Ge powder mixture to achieve near-band-edge (NBE) emission of ZnO and visible emission of GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires with controllable intensities. The nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture, particularly, by using different Zn:Ge ratio, temperature and evaporated times. The morphology of nanowires was depended on the Zn and Ge ratio that was observed to have a nanowire structure to rod-like morphology. The thermal evaporation of Zn:Ge powder mixture resulted in formation of dominant ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires as a function of evaporated parameters. These results suggest that the application of thermal evaporation of Zn and Ge mixture for potential application in synthesis of ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires for optoelectronic field.

  7. Experimental investigation of a building integrated photovoltaic/thermal roof collector combined with a liquid desiccant enhanced indirect evaporative cooling system

    International Nuclear Information System (INIS)

    Buker, Mahmut Sami; Mempouo, Blaise; Riffat, Saffa B.

    2015-01-01

    Highlights: • Novel solar thermal collector for liquid desiccant air conditioning was introduced. • Low cost poly heat exchanger loop underneath the photovoltaic modules was proposed. • The ability of the combined system was experimentally investigated. • Water temperature in the loop could reach up to 35.5 °C during the tests. • This tri-gen system can supply 3 kW heating, 5.2 kW cooling and 10.3 MW h/year power. - Abstract: Large consumption of limited conventional fossil fuel resources, economic and environmental problems associated with the global warming and climate change have emphasized the immediate need to transition to renewable energy resources. Solar thermal applications along with renewable energy based cooling practices have attracted considerable interest towards sustainable solutions promising various technical, economic and environmental benefits. This study introduces a new concept on solar thermal energy driven liquid desiccant based dew point cooling system that integrates several green technologies; including photovoltaic modules, polyethylene heat exchanger loop and a combined liquid desiccant dehumidification-indirect evaporative air conditioning unit. A pilot scale experimental set-up was developed and tested to investigate the performance of the proposed system and influence of the various parameters such as weather condition, air flow and regeneration temperature. A cost effective, easy-to-make polyethylene heat exchanger loop was employed underneath PV panels for heat generation. In addition, a liquid desiccant enhanced dew point cooling unit was utilized to provide air conditioning through dehumidification of humid air and indirect evaporative cooling. The experimental results show that the proposed tri-generation system is capable of providing about 3 kW of heating, 5.2 kW of cooling power and 10.3 MW h/year power generation, respectively. The findings confirm the potential of the examined technology, and elucidate the

  8. Advances in solid-catalytic and non-catalytic technologies for biodiesel production

    International Nuclear Information System (INIS)

    Islam, Aminul; Taufiq-Yap, Yun Hin; Chan, Eng-Seng; Moniruzzaman, M.; Islam, Saiful; Nabi, Md. Nurun

    2014-01-01

    Highlights: • The recent technologies for promoting biodiesel synthesis were elucidated. • The design of catalyst consideration of biodiesel production was proposed. • The recent advances and remaining difficulties in biodiesel synthesis were outlined. • The future research trend in biodiesel synthesis was highlighted. - Abstract: The insecure supply of fossil fuel coerces the scientific society to keep a vision to boost investments in the renewable energy sector. Among the many renewable fuels currently available around the world, biodiesel offers an immediate impact in our energy. In fact, a huge interest in related research indicates a promising future for the biodiesel technology. Heterogeneous catalyzed production of biodiesel has emerged as a preferred route as it is environmentally benign needs no water washing and product separation is much easier. The number of well-defined catalyst complexes that are able to catalyze transesterification reactions efficiently has been significantly expanded in recent years. The activity of catalysts, specifically in application to solid acid/base catalyst in transesterification reaction depends on their structure, strength of basicity/acidity, surface area as well as the stability of catalyst. There are various process intensification technologies based on the use of alternate energy sources such as ultrasound and microwave. The latest advances in research and development related to biodiesel production is represented by non-catalytic supercritical method and focussed exclusively on these processes as forthcoming transesterification processes. The latest developments in this field featuring highly active catalyst complexes are outlined in this review. The knowledge of more extensive research on advances in biofuels will allow a deeper insight into the mechanism of these technologies toward meeting the critical energy challenges in future

  9. Impact of additional sulphur on structure, morphology and optical properties of SnS thin films by thermal evaporation

    Science.gov (United States)

    Banotra, Arun; Padha, Naresh; Kumar, Shiv; Kapoor, Ashok K.

    2018-05-01

    Thin films of SnS have been obtained from Sn and S powders which were mixed up using ball mill technique with and without evaporating additional sulphur prior to annealing at 523K. The obtained samples were taken for structural, optical, chemical and morphological studies. The X-ray diffraction reveals the formation of SnS phase on annealing in vacuum having S/Sn ratio of 0.67 obtained from EDAX. This deficit in `S' is removed by supplementing additional `S' of 200nm prior to annealing which results in the S/Sn ratio of 1.01. The optical transmission recorded from spectrophotometer used to study different optical parameters. Morphological results corroborate well with the XRD, EDAX and optical study. The obtained stoichiometric films were also tested for Ag/p-SnS Schottky diodes on In coated glass substrates using current voltage measurements.

  10. Effect of Ge Addition on the Optical Band Gap and Refractive Index of Thermally Evaporated As2Se3 Thin Films

    Directory of Open Access Journals (Sweden)

    Pankaj Sharma

    2008-01-01

    Full Text Available The present paper reports the effect of Ge addition on the optical band gap and refractive index of As2Se3 thin films. Thin films of As2Se3 and (As2Se390Ge10 were prepared by thermal evaporation technique at base pressure 10−4 Pa. Optical band gap and refractive index were calculated by analyzing the transmission spectrum in the spectral range 400–1500 nm. The optical band gap decreases while the refractive index increases with the addition of Ge to As2Se3. The decrease of optical band gap has been explained on the basis of density of states; and the increase in refractive index has been explained on the basis increase in disorder in the system.

  11. Catalyst-free growth of ZnO nanowires on ITO seed/glass by thermal evaporation method: Effects of ITO seed layer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Alsultany, Forat H., E-mail: foratusm@gmail.com; Ahmed, Naser M. [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hassan, Z. [Institute of Nano-Optoelectronics Research and Technology Laboratory (INOR), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2016-07-19

    A seed/catalyst-free growth of ZnO nanowires (ZnO-NWs) on a glass substrate were successfully fabricated using thermal evaporation technique. These nanowires were grown on ITO seed layers of different thicknesses of 25 and 75 nm, which were deposited on glass substrates by radio frequency (RF) magnetron sputtering. Prior to synthesized ITO nanowires, the sputtered ITO seeds were annealed using the continuous wave (CW) CO2 laser at 450 °C in air for 15 min. The effect of seed layer thickness on the morphological, structural, and optical properties of ZnO-NWs were systematically investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and UV-Vis spectrophotometer.

  12. Stability enhancement of P3HT:PCBM polymer solar cells using thermally evaporated MoO3 anode buffer layer

    Science.gov (United States)

    Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Radhakrishnan, Thulasi; Reddy, V. S.

    2018-02-01

    Polymer solar cells have been fabricated with thermally evaporated MoO3 as anode buffer layer (ABL). The stability of MoO3 and PEDOT:PSS based devices was examined under different test conditions. The MoO3 based device exhibited a slightly better efficiency and significantly higher stability compared to PEDOT:PSS based device. At a relative humidity of 45% the unencapsulated PEDOT:PSS based device degraded completely within 96 h. On the other hand, MoO3 based device retained more than 60% of its initial efficiency after 96 h. The reason behind stability enhancement was investigated by measuring time-evolution of reflectance and hole-current. Experimental results revealed that the stability enhancement for MoO3 based device originates from the reduction in degradation of anode/active layer interface.

  13. Synthesis of ZnO Nanowires via Hotwire Thermal Evaporation of Brass (CuZn Assisted by Vapor Phase Transport of Methanol

    Directory of Open Access Journals (Sweden)

    Tamil Many K. Thandavan

    2014-01-01

    Full Text Available Zinc oxide (ZnO nanowires (NWs were synthesized using vapor phase transport (VPT and thermal evaporation of Zn from CuZn. Time dependence of ZnO NWs growth was investigated for 5, 10, 15, 20, 25, and 30 minutes. Significant changes were observed from the field electron scanning electron microscopy (FESEM images as well as from the X-ray diffraction (XRD profile. The photoluminescence (PL profile was attributed to the contribution of oxygen vacancy, zinc interstitials, and hydrogen defects in the ZnO NWs. Raman scattering results show a significant peak at 143 cm−1 and possible functionalization on the wall of ZnO NWs. Growth of ZnO NWs in (0002 with an estimated distance between adjacent lattice planes 0.26 nm was determined from transmission electron microscopy (TEM analysis.

  14. Photoelectric properties by interface effect of organic/inorganic(CuPc/PbTe) multilayer prepared by pulsed laser deposition and thermal evaporation

    CERN Document Server

    Lee, H Y; Choi, B C; Jeong, J H; Tabata, H; Kawai, T

    1999-01-01

    Highly crystallized CuPc/PbTe multilayer are prepared at substrate temperature from room temperature to 300 .deg. C by pulsed laser deposition and thermal evaporation method. From the measurement of AFM image, these all film exhibits composed of round grains and flat matrix. For observation the interface effect of multilayer, we measured the transverse current-voltage characteristics in the dark and under illumination. The photocarrier is generated in the CuPc layer and the electron-hole pairs are separated by the steep incline of the potential near the CuPc/PbTe interface. The CuPc/PbTe multilayers in the in-plane current-voltage curve exhibit larger photoconduction effect than that of CuPc single layer.

  15. Effect of thermal annealing on the structural and optical properties of Cu2FeSnS4 thin films grown by vacuum evaporation method

    Science.gov (United States)

    Oueslati, H.; Rabeh, M. Ben; Kanzari, M.

    2018-02-01

    In this work, the effect of different types of thermal annealing on the properties of Cu2FeSnS4 (CFTS) thin films deposited by thermal evaporation at room temperature on glass substrate were investigated. CFTS powder was synthesized by direct melting of the constituent elements taken in stoichiometry compositions. The X-ray diffraction experimental data indicating that the Cu2FeSnS4 powder illustrating a stannite structure in space group I\\bar {4}2m. From the XRD analysis we have found that the polycrystalline CFTS thin film was only obtained by thermal annealed in sulfur atmosphere under a high vacuum of 400 °C temperature during 2 h. Optical study reveals that the thin films have relatively high absorption coefficients (≈ 105cm-1) and the values of optical band gap energy ranged between 1.38 and 1.48 eV. Other optical parameters were evaluated according to the models of Wemple Di-Domenico and Spitzer-Fan. Finally, hot probe measurements of CFTS thin films reveal p-type conductivity.

  16. Study of structural and morphological properties of thermally evaporated Sn{sub 2}Sb{sub 6}S{sub 11} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Mehrez, N., E-mail: najia.benmehrez@gmail.com [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Khemiri, N. [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Kanzari, M. [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Institut Préparatoire aux Etudes d’Ingénieurs de Tunis Montfleury, Université de Tunis (Tunisia)

    2016-10-01

    In this study, we report the structural and morphological properties of the new material Sn{sub 2}Sb{sub 6}S{sub 11} thin films prepared on glass substrates by vacuum thermal evaporation at various substrate temperatures (30, 60, 100, 140, 180 and 200 °C). Sn{sub 2}Sb{sub 6}S{sub 11} ingot was synthesized by the horizontal Bridgman technique. The structural properties of Sn{sub 2}Sb{sub 6}S{sub 11} powder were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The films were characterized for their structural properties by using XRD. All films were polycrystalline in nature. The variations of the structural parameters of the films with the substrate temperature were investigated. The results show that the crystallite sizes increase as the substrate temperature increases. The morphological properties of the films were analyzed by atomic force microscopy (AFM). The roughness and the topography of the surface of the films strongly depend on the substrate temperature. - Highlights: • Sn{sub 2}Sb{sub 6}S{sub 11} powder was successfully synthesized by the horizontal Bridgman technique. • Sn{sub 2}Sb{sub 6}S{sub 11} films were grown by thermal evaporation at different substrate temperatures. • Structural properties of Sn{sub 2}Sb{sub 6}S{sub 11} powder were investigated. • The effect of the substrate temperature on structural and morphological of Sn{sub 2}Sb{sub 6}S{sub 11} films properties was studied.

  17. Gas sensing properties of zinc stannate (Zn{sub 2}SnO{sub 4}) nanowires prepared by carbon assisted thermal evaporation process

    Energy Technology Data Exchange (ETDEWEB)

    Tharsika, T., E-mail: tharsika@siswa.um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Akbar, S.A., E-mail: akbar.1@osu.edu [Center for Industrial Sensors and Measurements (CISM), Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43210 (United States); Sabri, M.F.M., E-mail: faizul@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Wong, Y.H., E-mail: yhwong@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-01-05

    Highlights: • Zn{sub 2}SnO{sub 4} nanowires are grown on Au/alumina substrate by a carbon assisted thermal evaporation process. • Optimum growth conditions for Zn{sub 2}SnO{sub 4} nanowires are determined. • Ethanol gas is selectively sensed with high sensitivity. - Abstract: Zn{sub 2}SnO{sub 4} nanowires are successfully synthesized by a carbon assisted thermal evaporation process with the help of a gold catalyst under ambient pressure. The as-synthesized nanowires are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) equipped with an energy dispersive X-ray spectroscopy (EDS). The XRD patterns and elemental mapping via TEM–EDS clearly indicate that the nanowires are Zn{sub 2}SnO{sub 4} with face centered spinel structure. HRTEM image confirms that Zn{sub 2}SnO{sub 4} nanowires are single crystalline with an interplanar spacing of 0.26 nm, which is ascribed to the d-spacing of (3 1 1) planes of Zn{sub 2}SnO{sub 4}. The optimum processing condition and a possible formation mechanism of these Zn{sub 2}SnO{sub 4} nanowires are discussed. Additionally, sensor performance of Zn{sub 2}SnO{sub 4} nanowires based sensor is studied for various test gases such as ethanol, methane and hydrogen. The results reveal that Zn{sub 2}SnO{sub 4} nanowires exhibit excellent sensitivity and selectivity toward ethanol with quick response and recovery times. The response of the Zn{sub 2}SnO{sub 4} nanowires based sensors to 50 ppm ethanol at an optimum operating temperature of 500 °C is about 21.6 with response and recovery times of about 116 s and 182 s, respectively.

  18. Interfacial Instabilities in Evaporating Drops

    Science.gov (United States)

    Moffat, Ross; Sefiane, Khellil; Matar, Omar

    2007-11-01

    We study the effect of substrate thermal properties on the evaporation of sessile drops of various liquids. An infra-red imaging technique was used to record the interfacial temperature. This technique illustrates the non-uniformity in interfacial temperature distribution that characterises the evaporation process. Our results also demonstrate that the evaporation of methanol droplets is accompanied by the formation of wave-trains in the interfacial temperature field; similar patterns, however, were not observed in the case of water droplets. More complex patterns are observed for FC-72 refrigerant drops. The effect of substrate thermal conductivity on the structure of the complex pattern formation is also elucidated.

  19. Transfer Efficiency and Cooling Cost by Thermal Loss based on Nitrogen Evaporation Method for Superconducting MAGLEV System

    International Nuclear Information System (INIS)

    Chung, Y D; Kim, D W; Lee, C Y

    2017-01-01

    This paper presents the feasibility of technical fusion between wireless power transfer (WPT) and superconducting technology to improve the transfer efficiency and evaluate operating costs such as refrigerant consumption. Generally, in WPT technology, the various copper wires have been adopted. From this reason, the transfer efficiency is limited since the copper wires of Q value are intrinsically critical point. On the other hand, as superconducting wires keep larger current density and relatively higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. However, since superconducting wires should be cooled indispensably, the cooling cost of consumed refrigerant for resonance HTS wires should be estimated. In this study, the transmission ratios using HTS resonance receiver (Rx) coil and various cooled and noncooled copper resonance Rx coils were presented under non cooled copper antenna within input power of 200 W of 370 kHz respectively. In addition, authors evaluated cooling cost of liquid nitrogen for HTS resonance coil and various cooled copper resonance coils based on nitrogen evaporation method. (paper)

  20. Transfer Efficiency and Cooling Cost by Thermal Loss based on Nitrogen Evaporation Method for Superconducting MAGLEV System

    Science.gov (United States)

    Chung, Y. D.; Kim, D. W.; Lee, C. Y.

    2017-07-01

    This paper presents the feasibility of technical fusion between wireless power transfer (WPT) and superconducting technology to improve the transfer efficiency and evaluate operating costs such as refrigerant consumption. Generally, in WPT technology, the various copper wires have been adopted. From this reason, the transfer efficiency is limited since the copper wires of Q value are intrinsically critical point. On the other hand, as superconducting wires keep larger current density and relatively higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. However, since superconducting wires should be cooled indispensably, the cooling cost of consumed refrigerant for resonance HTS wires should be estimated. In this study, the transmission ratios using HTS resonance receiver (Rx) coil and various cooled and noncooled copper resonance Rx coils were presented under non cooled copper antenna within input power of 200 W of 370 kHz respectively. In addition, authors evaluated cooling cost of liquid nitrogen for HTS resonance coil and various cooled copper resonance coils based on nitrogen evaporation method.

  1. Evaporator bulb

    International Nuclear Information System (INIS)

    Stoll, W.

    1977-01-01

    In order to prevent the hazard of a possible excursion in an evaporator bulb for radioactive liquids there is provided in the bottom of the vessel a recess filled with a neutron-absorbing and moderating material. The bottom drain pipe is coming out sideways and connected with a heated pipe feeding above into the vessel tangentially. (TK) [de

  2. Evaporating firewalls

    Science.gov (United States)

    Van Raamsdonk, Mark

    2014-11-01

    In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.

  3. Non-catalytic alcoholysis process for production of biodiesel fuel by using bubble column reactor

    Science.gov (United States)

    Hagiwara, S.; Nabetani, H.; Nakajima, M.

    2015-04-01

    -edible lipids by use of the SMV reactor has not been examined yet. Therefore, this study aims to investigate the productivity of biodiesel produced from waste vegetable oils using the SMV reactor. Biodiesel fuel is a replacement for diesel as a fuel produced from biomass resources. It is generally produced as a FAME derived from vegetable oil by using alkaline catalyzed alcoholysis process. This alkaline method requires deacidification process prior to the reaction process and the alkaline catalyst removal process after the reaction. Those process increases the total cost of biodiesel fuel production. In order to solve the problems in the conventional alkaline catalyzed alcoholysis process, the authors proposed a non-catalytic alcoholysis process called the Superheated Methanol Vapor (SMV) method with bubble column reactor. So, this study aims to investigate the productivity of biodiesel produced from vegetable oils and other lipids using the SMV method with bubble column reactor.

  4. Non-catalytic alcoholysis process for production of biodiesel fuel by using bubble column reactor

    International Nuclear Information System (INIS)

    Hagiwara, S; Nabetani, H; Nakajima, M

    2015-01-01

    -edible lipids by use of the SMV reactor has not been examined yet. Therefore, this study aims to investigate the productivity of biodiesel produced from waste vegetable oils using the SMV reactor. Biodiesel fuel is a replacement for diesel as a fuel produced from biomass resources. It is generally produced as a FAME derived from vegetable oil by using alkaline catalyzed alcoholysis process. This alkaline method requires deacidification process prior to the reaction process and the alkaline catalyst removal process after the reaction. Those process increases the total cost of biodiesel fuel production. In order to solve the problems in the conventional alkaline catalyzed alcoholysis process, the authors proposed a non-catalytic alcoholysis process called the Superheated Methanol Vapor (SMV) method with bubble column reactor. So, this study aims to investigate the productivity of biodiesel produced from vegetable oils and other lipids using the SMV method with bubble column reactor

  5. Liquid evaporation process and evaporator

    International Nuclear Information System (INIS)

    Bergey, Claude; Ravenel, Jacques.

    1975-01-01

    The process described enables a liquid to be evaporated rapidly without any projection. A jet of hot gas is applied to the liquid, the power and angle of the jet being chosen so as to spin the liquid. It is particularly used in the case of radioactive products [fr

  6. Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study

    OpenAIRE

    Nyoman Puspa Asri; Siti Machmudah; W. Wahyudiono; S. Suprapto; Kusno Budikarjono; Achmad Roesyadi; Motonobu Goto

    2013-01-01

    Non catalytic transesterification in sub and supercritical methanol have been used to produce biodiesel from palm oil and soybean oil. A kinetic study was done under reaction condition with temperature and time control. The experiments were carried out in a batch type reactor at reaction temperatures from 210 °C (subcritical condition) to 290 °C (the supercritical state) in the interval ranges of temperature of 20 °C and at various molar ratios of oil to methanol. The rate constants of the re...

  7. Processivity and Subcellular Localization of Glycogen Synthase Depend on a Non-catalytic High Affinity Glycogen-binding Site*

    OpenAIRE

    Díaz, Adelaida; Martínez-Pons, Carlos; Fita, Ignacio; Ferrer, Juan C.; Guinovart, Joan J.

    2011-01-01

    Glycogen synthase, a central enzyme in glucose metabolism, catalyzes the successive addition of α-1,4-linked glucose residues to the non-reducing end of a growing glycogen molecule. A non-catalytic glycogen-binding site, identified by x-ray crystallography on the surface of the glycogen synthase from the archaeon Pyrococcus abyssi, has been found to be functionally conserved in the eukaryotic enzymes. The disruption of this binding site in both the archaeal and the human muscle glycogen synth...

  8. Thermal evolution of the morphology, structure, and optical properties of multilayer nanoperiodic systems produced by the vacuum evaporation of SiO and SiO2

    International Nuclear Information System (INIS)

    Ershov, A. V.; Chugrov, I. A.; Tetelbaum, D. I.; Mashin, A. I.; Pavlov, D. A.; Nezhdanov, A. V.; Bobrov, A. I.; Grachev, D. A.

    2013-01-01

    The alternate vacuum evaporation of SiO and SiO 2 from separate sources is used to produce amorphous a-SiO x /SiO 2 multilayer nanoperiodic structures with periods of 5–10 nm and a number of layers of up to 64. The effect of annealing at temperatures T a = 500–1100°C on the structural and optical properties of the nanostructures is studied. The results of transmission electron microscopy of the samples annealed at 1100°C indicate the annealing-induced formation of vertically ordered quasiperiodic arrays of Si nanocrystals, whose dimensions are comparable to the a-SiO x -layer thickness in the initial nanostructures. The nanostructures annealed at 1100°C exhibit size-dependent photoluminescence in the wavelength range 750–830 nm corresponding to Si nanocrystals. The data on infrared absorption and Raman scattering show that the thermal evolution of structural and phase state of the SiO x layers with increasing annealing temperature proceeds through the formation of amorphous Si nanoinclusions with the subsequent formation and growth of Si nanocrystals.

  9. Effect of a thermally evaporated bis (2-methyl-8-quninolinato)-4-phenylphenolate cathode buffer layer on the performance of polymer photovoltaic cells

    International Nuclear Information System (INIS)

    Kim, Dal-Ho; Park, Jea-Gun

    2012-01-01

    We investigated the device characteristics of polymer photovoltaic (PV) cells based on a poly(3 hexylthiophene) (P3HT) and [6,6]-phenylC61 butyric acid methyl ester (PCBM) bulk heterojunction with a cathode buffer layer of thermally evaporated bis (2-methyl-8-quninolinato)-4-phenylphenolate (BAlq). A power conversion efficiency (PCE) of 2.46% was obtained with the insertion of a 4-nm-thick BAlq, which was ∼118% increase over that for the cell without a BAlq layer, under Air Mass 1.5 Global (AM 1.5 G) illumination, 100 mW/cm 2 . Moreover, we examined the charge carrier transport property, and found that the hole mobility of the cell was enhancement due to the insertion of a BAlq layer with a thickness of less than 4 nm, which accounted for the improved in the photocurrent and fill factor (FF) due to the better balance of charge carriers. Finally, the BAlq buffer layer was also demonstrated as an optical spacer that improved the optical absorption of the P3HT:PCBM layer, which accounted for the J sc enhancement of the device.

  10. Structural, morphological, gas sensing and photocatalytic characterization of MoO3 and WO3 thin films prepared by the thermal vacuum evaporation technique

    Science.gov (United States)

    Arfaoui, A.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-12-01

    Thin films of molybdenum trioxide and tungsten trioxide were deposited on glass substrates using a simplified thermal evaporation under vacuum method monitored by heat treatment in flowing oxygen at 500 °C for 1 h. The structural and morphological properties of the films were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The X-ray diffraction analysis shows that the films of MoO3 and WO3 were well crystallized in orthorhombic and monoclinic phase respectively with the crystallites preferentially oriented toward (2 0 0) direction parallel a-axis for both samples. In literature, we have shown in previous papers that structural and surface morphology of metal thin films play an important role in the gas detection mechanism. In this article, we have studied the response evolution of MoO3 and WO3 thin films sensors ethanol versus time, working temperature and the concentration of the ethanol. It was found that these films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. Finally, the photocatalytic activity of the samples was evaluated with respect to the degradation reaction of a wastewater containing methylene blue (MB) under UV-visible light irradiation. The molybdenum trioxide exhibits a higher degradation rate than the tungsten trioxide thin films under similar experimental conditions.

  11. Comparison of satellite-derived LAI and precipitation anomalies over Brazil with a thermal infrared-based Evaporative Stress Index for 2003-2013

    Science.gov (United States)

    Anderson, Martha C.; Zolin, Cornelio A.; Hain, Christopher R.; Semmens, Kathryn; Tugrul Yilmaz, M.; Gao, Feng

    2015-07-01

    Shortwave vegetation index (VI) and leaf area index (LAI) remote sensing products yield inconsistent depictions of biophysical response to drought and pluvial events that have occurred in Brazil over the past decade. Conflicting reports of severity of drought impacts on vegetation health and functioning have been attributed to cloud and aerosol contamination of shortwave reflectance composites, particularly over the rainforested regions of the Amazon basin which are subject to prolonged periods of cloud cover and episodes of intense biomass burning. This study compares timeseries of satellite-derived maps of LAI from the Moderate Resolution Imaging Spectroradiometer (MODIS) and precipitation from the Tropical Rainfall Mapping Mission (TRMM) with a diagnostic Evaporative Stress Index (ESI) retrieved using thermal infrared remote sensing over South America for the period 2003-2013. This period includes several severe droughts and floods that occurred both over the Amazon and over unforested savanna and agricultural areas in Brazil. Cross-correlations between absolute values and standardized anomalies in monthly LAI and precipitation composites as well as the actual-to-reference evapotranspiration (ET) ratio used in the ESI were computed for representative forested and agricultural regions. The correlation analyses reveal strong apparent anticorrelation between MODIS LAI and TRMM precipitation anomalies over the Amazon, but better coupling over regions vegetated with shorter grass and crop canopies. The ESI was more consistently correlated with precipitation patterns over both landcover types. Temporal comparisons between ESI and TRMM anomalies suggest longer moisture buffering timescales in the deeper rooted rainforest systems. Diagnostic thermal-based retrievals of ET and ET anomalies, such as used in the ESI, provide independent information on the impacts of extreme hydrologic events on vegetation health in comparison with VI and precipitation-based drought

  12. Biodiesel production with continuous supercritical process: non-catalytic transesterification and esterification with or without carbon dioxide.

    Science.gov (United States)

    Tsai, Yu-Ting; Lin, Ho-mu; Lee, Ming-Jer

    2013-10-01

    The non-catalytic transesterification of refined sunflower oil with supercritical methanol, in the presence of carbon dioxide, was conducted in a tubular reactor at temperatures from 553.2 to 593.2K and pressures up to 25.0 MPa. The FAME yield can be achieved up to about 0.70 at 593.2 K and 10.0 MPa in 23 min with methanol:oil of 25:1 in molar ratio. The effect of adding CO2 on the FAME yield is insignificant. The kinetic behavior of the non-catalytic esterification and transesterification of oleic acid or waste cooking oil (WCO) with supercritical methanol was also investigated. By using the supercritical process, the presence of free fatty acid (FFA) in WCO gives positive contribution to FAME production. The FAME yield of 0.90 from WCO can be achieved in 13 min at 573.2K. The kinetic data of supercritical transesterification and esterifaication were correlated well with a power-law model. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Role of heat treatment on structural and optical properties of thermally evaporated Ga{sub 10}Se{sub 81}Pb{sub 9} chalcogenide thin films

    Energy Technology Data Exchange (ETDEWEB)

    El-Sebaii, A.A., E-mail: ahmedelsebaii@yahoo.com [Department of Physics, Faculty of Science, King Abdulaziz University, 80203 Jeddah 21589 (Saudi Arabia); Khan, Shamshad A. [Department of Physics, St. Andrews College, Gorakhpur 273001 (India); Al-Marzouki, F.M.; Faidah, A.S.; Al-Ghamdi, A.A. [Department of Physics, Faculty of Science, King Abdulaziz University, 80203 Jeddah 21589 (Saudi Arabia)

    2012-08-15

    Amorphous chalcogenides, based on Se, have become materials of commercial importance and were widely used for optical storage media. The present work deals with the structural and optical properties of Ga{sub 10}Se{sub 81}Pb{sub 9} ternary chalcogenide glass prepared by melt quenching technique. The glass transition, crystallization and melting temperatures of the synthesized glass were measured by non-isothermal DSC measurements at a constant heating rate of 30 K/min. Thin films of thickness 4000 A were prepared by thermal evaporation techniques on glass/Si (1 0 0) wafer substrate. These thin films were thermally annealed for two hours at three different annealing temperatures of 345, 360 and 375 K, which were in between the glass transition and crystallization temperatures of the Ga{sub 10}Se{sub 81}Pb{sub 9} glass. The structural, morphological and optical properties of as-prepared and annealed thin films were studied. Analysis of the optical absorption data showed that the rules of the non-direct transitions predominate. It was also found that the optical band gap decreases while the absorption coefficient, refractive index and extinction coefficient increase with increasing the annealing temperature. Due to the higher values of absorption coefficient and annealing dependence of the optical band gap and optical constants, the investigated material could be used for optical storage. - Highlights: Black-Right-Pointing-Pointer Annealing effect on structure and optical band gap has been investigated. Black-Right-Pointing-Pointer The amorphous nature has been verified by x-ray diffraction and DSC measurements. Black-Right-Pointing-Pointer Thermal annealing causes a decrease in optical band gap in Ga{sub 10}Se{sub 81}Pb{sub 9} thin films. Black-Right-Pointing-Pointer The decrease in optical band gap can be interpreted on the basis of amorphous-crystalline phase transformation. Black-Right-Pointing-Pointer Optical absorption data showed that the rules of the non

  14. Catalyst-free combined synthesis of Zn/ZnO core/shell hollow microspheres and metallic Zn microparticles by thermal evaporation and condensation route

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Waheed S. [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China); Cao Chuanbao, E-mail: cbcao@bit.edu.c [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China); Nabi, Ghulam; Yao Ruimin; Bhatti, Sajjad H. [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China)

    2010-09-17

    Research highlights: {yields} Catalyst-free combined synthesis of metal/semiconductor Zn/ZnO core/shell microspheres with hollow interiors on Si substrate and metallic Zn polygonal microparticles on glass substrate in a single experiment via thermal evaporation and condensation technique was reported. The Zn/ZnO hollow microspheres were observed to have dimensions in the range of 70-80 {mu}m whereas metallic Zn microparticles with polygonal cross section and oblate spherical shape were found to be of 8-10 {mu}m. Some of the Zn/ZnO core/shell hollow spheres were also observed to have single crystalline ZnO pointed rods in extremely low density grown on the outer shell. A vapor-liquid-solid (VLS) process based growth mechanism was proposed for the formation of Zn/ZnO core/shell microspheres with hollow interior. The optical properties of Zn/ZnO core/shell microspheres were investigated by measuring the photoluminescence (PL) spectra at room temperature (RT). Two very strong emission bands were observed at 373 and 469 nm in the ultraviolet and visible regions respectively under excitation wavelength of 325 nm. Also the effect of the various excitation wavelengths on the PL behaviour was studied at room temperature. PL studies of Zn/ZnO core/shell microspheres show the promise of the material for applications in UV and blue light optical devices. - Abstract: Here we report catalyst-free combined synthesis of metal/semiconductor Zn/ZnO core/shell microspheres with hollow interiors on Si substrate and metallic Zn polygonal microparticles on glass substrate in a single experiment via thermal evaporation and condensation technique using nitrogen (N{sub 2}) as carrier agent at 800 {sup o}C for 120 min. The Zn/ZnO hollow microspheres were observed to have dimensions in the range of 70-80 {mu}m whereas metallic Zn microparticles with polygonal cross section and oblate spherical shape were found to be of 8-10 {mu}m. Some of the Zn/ZnO core/shell hollow spheres were also

  15. The sustained effect (12 months) of a single-dose vectored thermal pulsation procedure for meibomian gland dysfunction and evaporative dry eye.

    Science.gov (United States)

    Blackie, Caroline A; Coleman, Christy A; Holland, Edward J

    2016-01-01

    To evaluate the sustained effect (up to 1 year) of a single, 12-minute vectored thermal pulsation (VTP) treatment in improving meibomian gland function and dry eye symptoms in patients with meibomian gland dysfunction and evaporative dry eye. The prospective, multicenter, open-label clinical trial included 200 subjects (400 eyes) who were randomized to a single VTP treatment (treatment group) or twice-daily, 3-month, conventional warm compress and eyelid hygiene therapy (control group). Control group subjects received crossover VTP treatment at 3 months (crossover group). Effectiveness measures of meibomian gland secretion (MGS) and dry eye symptoms were evaluated at baseline and 1, 3, 6, 9, and 12 months. Subjects with inadequate symptom relief could receive additional meibomian gland dysfunction therapy after 3 (treatment group) and 6 months (crossover group). At 3 months, the treatment group had greater mean improvement in MGS (Pdry eye symptoms (P=0.0068), compared to controls. At 12 months, 86% of the treatment group had received only one VTP treatment, and sustained a mean improvement in MGS from 6.4±3.7 (baseline) to 17.3±9.1 (Pdry eye symptoms from 44.1±20.4 to 21.6±21.3 (Pdry eye symptoms from 49.1±21.0 to 24.0±23.2 (Pdry eye symptoms, over 12 months. A single VTP treatment provides significantly greater mean improvement in meibomian gland function and dry eye symptoms as compared to a conventional, twice-daily, 3-month regimen. Early VTP intervention for meibomian gland dysfunction is associated with improved treatment outcomes.

  16. Toward the Elucidation of the Competing Role of Evaporation and Thermal Decomposition in Ionic Liquids: A Multitechnique Study of the Vaporization Behavior of 1-Butyl-3-methylimidazolium Hexafluorophosphate under Effusion Conditions.

    Science.gov (United States)

    Volpe, V; Brunetti, B; Gigli, G; Lapi, A; Vecchio Ciprioti, S; Ciccioli, A

    2017-11-16

    The evaporation/decomposition behavior of the imidazolium ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF 6 ) was investigated in the overall temperature range 425-551 K by means of the molecular-effusion-based techniques Knudsen effusion mass loss (KEML) and Knudsen effusion mass spectrometry (KEMS), using effusion orifices of different size (from 0.2 to 3 mm in diameter). Specific effusion fluxes measured by KEML were found to depend markedly on the orifice size, suggesting the occurrence of a kinetically delayed evaporation/decomposition process. KEMS experiments revealed that other species are present in the vapor phase besides the intact ion pair BMImPF 6 (g) produced by the simple evaporation BMImPF 6 (l) = BMImPF 6 (g), with relative abundances depending on the orifice size-the larger the orifice, the larger the contribution of the BMImPF 6 (g) species. By combining KEML and KEMS results, the conclusion is drawn that in the investigated temperature range, when small effusion orifices are used, a significant part of the mass loss/volatility of BMImPF 6 is due to molecular products formed by decomposition/dissociation processes rather than to evaporated intact ion pairs. Additional experiments performed by nonisothermal thermogravimetry-differential thermal analysis (TG-DTA) further support the evidence of simultaneous evaporation/decomposition, although the conventional decomposition temperature derived from TG curves is much higher than the temperatures covered in effusion experiments. Partial pressures of the BMImPF 6 (g) species were derived from KEMS spectra and analyzed by second- and third-law methods giving a value of Δ evap H 298K ° = 145.3 ± 2.9 kJ·mol -1 for the standard evaporation enthalpy of BMImPF 6 . A comparison is done with the behavior of the 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf 2 ) ionic liquid.

  17. Thermal and chemical evolution in the early Solar System as recorded by FUN CAIs: Part II - Laboratory evaporation of potential CMS-1 precursor material

    Science.gov (United States)

    Mendybaev, Ruslan A.; Williams, Curtis D.; Spicuzza, Michael J.; Richter, Frank M.; Valley, John W.; Fedkin, Alexei V.; Wadhwa, Meenakshi

    2017-03-01

    We present the results of laboratory experiments in which a forsterite-rich melt estimated to be a potential precursor of Allende CMS-1 FUN CAI was evaporated into vacuum for different lengths of time at 1900 °C. The evaporation of this melt resulted in residues that define trajectories in chemical as well as magnesium, silicon and oxygen isotopic composition space and come very close to the measured properties of CMS-1. The isotopic composition of the evaporation residues was also used to determine the kinetic isotopic fractionation factors [α2,1 (vapor-melt) defined as the ratio of isotopes 2 and 1 of a given element in the evaporating gas divided by their ratio in the evaporating source] for evaporation of magnesium (α25,24 for 25Mg/24Mg), silicon (α29,28 for 29Si/28Si) and oxygen (α18,16 for 18O/16O) from the forsterite-rich melt at 1900 °C. The values of α25,24 = 0.98383 ± 0.00033 and α29,28 = 0.99010 ± 0.00038 are essentially independent of change in the melt composition as evaporation proceeds. In contrast, α18,16 changes from 0.9815 ± 0.0016 to ∼0.9911 when the residual melt composition changes from forsteritic to melilitic. Using the determined values of α25,24 and α29,28 and present-day bulk chemical composition of the CMS-1, the composition of the precursor of the inclusion was estimated to be close to the clinopyroxene + spinel + forsterite assemblage condensed from a solar composition gas. The correspondence between the chemical composition and isotopic fractionation of experimental evaporation residues and the present-day bulk chemical and isotopic compositions of CMS-1 is evidence that evaporation played a major role in the chemical evolution of CMS-1.

  18. Kinetic Parameters of Non-Isothermal Thermogravimetric Non-Catalytic and Catalytic Pyrolysis of Empty Fruit Bunch with Alumina by Kissinger and Ozawa Methods

    Science.gov (United States)

    Rahayu Mohamed, Alina; Li, Nurfahani; Sohaimi, Khairunissa Syairah Ahmad; Izzati Iberahim, Nur; Munirah Rohaizad, Nor; Hamzah, Rosniza

    2018-03-01

    The non-isothermal thermogravimetric non-catalytic and catalytic empty fruit bunch (EFB) pyrolysis with alumina were performed at different heating rates of 10, 15, 20, 25, 30 and 40 K/min under nitrogen atmosphere at a flow rate of 100 ml/min under dynamic conditions from 301 K to 1273 K. The activation energy were calculated based on Kissinger and Ozawa methods. Both reactions followed first order reactions. By Kissinger method, the activation energy and Ln A values for non-catalytic and catalytic EFB pyrolysis with alumina were 188.69 kJ mol-1 and 201.67 kJ/mol respectively. By Ozawa method, the activation energy values for non-catalytic and catalytic EFB pyrolysis with alumina were 189.13 kJ/mol and 201.44 kJ/mol respectively. The presence of catalyst increased the activation energy values for EFB pyrolysis as calculated by Kissinger and Ozawa methods.

  19. Non-catalytic direct synthesis of graphene on Si (111) wafers by using inductively-coupled plasma chemical vapor deposition

    Science.gov (United States)

    Hwang, Sung Won; Shin, Hyunho; Lee, Bongsoo; Choi, Suk-Ho

    2016-08-01

    We employ inductively-coupled plasma chemical vapor deposition for non-catalytic growth of graphene on a Si (111) wafer or glass substrate, which is useful for practical device applications of graphene without transfer processes. At a RF power (P) of 500 W under C2H2 flow, defect-free 3 ˜ 5-layer graphene is grown on Si (111) wafers, but on glass substrate, the layer is thicker and defective, as characterized by Raman spectroscopy and electron microscopy. The graphene is produced on Si (111) for P down to 190 W whereas it is almost not formed on glass for P < 250 W, possibly resulting from the weak catalytic-reaction-like effect on glass. These results are discussed based on possible growth mechanisms.

  20. Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study

    Directory of Open Access Journals (Sweden)

    Nyoman Puspa Asri

    2013-03-01

    Full Text Available Non catalytic transesterification in sub and supercritical methanol have been used to produce biodiesel from palm oil and soybean oil. A kinetic study was done under reaction condition with temperature and time control. The experiments were carried out in a batch type reactor at reaction temperatures from 210 °C (subcritical condition to 290 °C (the supercritical state in the interval ranges of temperature of 20 °C and at various molar ratios of oil to methanol. The rate constants of the reaction were determined by employing a simple method, with the overall chemical reaction followed the pseudo-first–order reaction. Based on the results, the rate constants of vegetables oil were significantly influenced by reaction temperature, which were gradually increased at subcritical temperature, but sharply increased in the supercritical state. However, the rate constants of soybean oil were slightly higher than that of palm oil. The activation energy for transesterification of soybean oil was 89.32 and 79.05 kJ/mole for palm oil. Meanwhile, the frequency factor values of both oils were 72462892 and 391210 min-1, respectively. The rate reaction for both of oil were expressed as -rTG = 72462892 exp(-89.32/RTCTG for soybean oil and -rTG = 391210 exp(-79.05/RTCTG for palm oil. © 2013 BCREC UNDIP. All rights reservedReceived: 18th October 2012; Revised: 14th December 2012; Accepted: 16th December 2012[How to Cite: N.P. Asri, S. Machmudah, W. Wahyudiono, S. Suprapto, K. Budikarjono, A. Roesyadi, M. Goto, (2013. Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 215-223. (doi:10.9767/bcrec.7.3.4060.215-223][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4060.215-223 ] View in  |

  1. Structuring of polymer solutions upon solvent evaporation

    NARCIS (Netherlands)

    Schaefer, C.; van der Schoot, P.|info:eu-repo/dai/nl/102140618; Michels, J. J.

    2015-01-01

    The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench

  2. Realistic thermal transient margin analysis of 'MONJU' based on plant performance measurements. Reactor vessel outlet nozzle and evaporator feed water inlet tube sheet of the manual reactor plant trip

    International Nuclear Information System (INIS)

    Yamada, Fumiaki; Mori, Takero

    2005-01-01

    In order to develop technologies and achieve safe and stable operation of Monju' as well as realize optimized design and construction of safe and economically competitive fast breeder reactors, the authors are evaluating design approach applied to 'Monju' based on actually measured behavioral data during plant operations. This report uses actual measured characteristic data of 'Monju' during a plant trip test obtained at a commissioning stage with up to 40% power output and introduces plant thermal hydraulic behavior analysis in a representative thermal transient event, i.e. a manual plant trip. Thermal transient driven loads incurred by the reactor vessel outlet nozzle and by the evaporator feed water inlet tube sheet were further derived by structural analyses and were compared with the previously derived values in the design stage and with the limit values. Though the reactor vessel outlet nozzle was exposed to larger temperature change in the trip test than the analytical prediction, the newly calculated mechanical load was about 50% of the previous evaluation in the design stage. Also, the newly analyzed mechanical load incurred by the evaporator feed water inlet tube sheet in this event had a large margin against the limit value of cumulative damage cycle fraction, although the observed temperature disturbance in a steam blow test was wilder than the analytical prediction. Thus we concluded that the Monju' plant has an assured safety margin against thermal transient in plant trip events. (author)

  3. Fundamental mechanisms and reactions in non-catalytic subcritical hydrothermal processes: A review.

    Science.gov (United States)

    Yousefifar, Azadeh; Baroutian, Saeid; Farid, Mohammed M; Gapes, Daniel J; Young, Brent R

    2017-10-15

    The management and disposal of solid waste is of increasing concern across the globe. Hydrothermal processing of sludge has been suggested as a promising solution to deal with the considerable amounts of sludge produced worldwide. Such a process not only degrades organic compounds and reduces waste volume, but also provides an opportunity to recover valuable substances. Hydrothermal processing comprises two main sub-processes: wet oxidation (WO) and thermal hydrolysis (TH), in which the formation of various free radicals results in the production of different intermediates. Volatile fatty acids (VFAs), especially acetic acid, are usually the main intermediates which remain as a by-product of the process. This paper aims to review the fundamental mechanism for hydrothermal processing of sludge, and the formation of different free radicals and intermediates therein. In addition, the proposed kinetic models for the two processes (WO and TH) from the literature are reviewed and the advantages and disadvantages of each model are outlined. The effect of mass transfer as a critical component of the design and development of the processes, which has been neglected in most of these proposed models, is also reviewed, and the effect of influencing parameters on the processes' controlling step (reaction or mass transfer) is discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Denton E-beam Evaporator #1

    Data.gov (United States)

    Federal Laboratory Consortium — Description:CORAL Name: E-Beam Evap 1This is a dual e-beam/thermal evaporator for the deposition of metal and dielectric thin films. Materials available are: Ag, Al,...

  5. PFR evaporator leak

    International Nuclear Information System (INIS)

    Smedley, J.A.

    1975-01-01

    PFR has three heat removal circuits each one having an evaporator, superheater, reheater; all separate units. The status of the system was that circuit No 3 was steaming with 10 MW thermal nuclear power; No 1 circuit was filled with sodium but with the evaporator awaiting modification to cure gas entrainment problems already reported. The leak was in No 2 circuit and was located in the evaporator unit. The evaporator is rated at 120 M thermal at full power and as such is a large unit. The circuit was filled with both sodium and water for the first time three weeks before the conference so it was recent history being reported and therefore any figures quoted should be taken as indicative only. The history of the steam generator was that it was built at works to a very high standard and underwent all the usual tests of strength, inspection of welds and helium leak testing. The steam generator is of U tube design with a tube plate to which the boiler tubes are welded, with all the welds in one of two gas spaces. The inlet and outlet sides are separated by a baffle and the salient features are illustrated in the attached figure. The unit achieved a leak tightness better than the detection limit in the helium leak test at works. This limit was assessed as being less than an equivalent leak of 10 -6 g/s water under steam generator service conditions. However even though all the steam generator units passed this test at works a further test was carried out when the circuits had been completed. The test was carried out during commissioning after sodium filling and with the units hot. The method was to introduce a mixture of helium/ argon at 500 pounds/square inch into the water side of the steam generators and measure the helium concentration in the sodium side gas spaces of the circuit. The test lasted many days and under these conditions the sensitivity is such that a leak equivalent to somewhere between 10 -7 to 10 -6 g/s equivalent water leak could be detected, i

  6. PFR evaporator leak

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, J A

    1975-07-01

    PFR has three heat removal circuits each one having an evaporator, superheater, reheater; all separate units. The status of the system was that circuit No 3 was steaming with 10 MW thermal nuclear power; No 1 circuit was filled with sodium but with the evaporator awaiting modification to cure gas entrainment problems already reported. The leak was in No 2 circuit and was located in the evaporator unit. The evaporator is rated at 120 M thermal at full power and as such is a large unit. The circuit was filled with both sodium and water for the first time three weeks before the conference so it was recent history being reported and therefore any figures quoted should be taken as indicative only. The history of the steam generator was that it was built at works to a very high standard and underwent all the usual tests of strength, inspection of welds and helium leak testing. The steam generator is of U tube design with a tube plate to which the boiler tubes are welded, with all the welds in one of two gas spaces. The inlet and outlet sides are separated by a baffle and the salient features are illustrated in the attached figure. The unit achieved a leak tightness better than the detection limit in the helium leak test at works. This limit was assessed as being less than an equivalent leak of 10{sup -6} g/s water under steam generator service conditions. However even though all the steam generator units passed this test at works a further test was carried out when the circuits had been completed. The test was carried out during commissioning after sodium filling and with the units hot. The method was to introduce a mixture of helium/ argon at 500 pounds/square inch into the water side of the steam generators and measure the helium concentration in the sodium side gas spaces of the circuit. The test lasted many days and under these conditions the sensitivity is such that a leak equivalent to somewhere between 10{sup -7} to 10{sup -6} g/s equivalent water leak could be

  7. Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media

    Directory of Open Access Journals (Sweden)

    Mahfud Mahfud

    2011-02-01

    Full Text Available This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst

  8. Non-Catalytic Functions of Pyk2 and Fyn Regulate Late Stage Adhesion in Human T Cells

    Science.gov (United States)

    Houtman, Jon C. D.

    2012-01-01

    T cell activation drives the protective immune response against pathogens, but is also critical for the development of pathological diseases in humans. Cytoskeletal changes are required for downstream functions in T cells, including proliferation, cytokine production, migration, spreading, and adhesion. Therefore, investigating the molecular mechanism of cytoskeletal changes is crucial for understanding the induction of T cell-driven immune responses and for developing therapies to treat immune disorders related to aberrant T cell activation. In this study, we used a plate-bound adhesion assay that incorporated near-infrared imaging technology to address how TCR signaling drives human T cell adhesion. Interestingly, we observed that T cells have weak adhesion early after TCR activation and that binding to the plate was significantly enhanced 30–60 minutes after receptor activation. This late stage of adhesion was mediated by actin polymerization but was surprisingly not dependent upon Src family kinase activity. By contrast, the non-catalytic functions of the kinases Fyn and Pyk2 were required for late stage human T cell adhesion. These data reveal a novel TCR-induced signaling pathway that controls cellular adhesion independent of the canonical TCR signaling cascade driven by tyrosine kinase activity. PMID:23300847

  9. Experimental investigation of N2O formation in selective non-catalytic NOx reduction processes performed in stoker boiler

    Directory of Open Access Journals (Sweden)

    Krawczyk Piotr

    2016-12-01

    Full Text Available Stoker fired boiler plants are common throughout Eastern Europe. Increasingly strict emission standards will require application of secondary NOx abatement systems on such boilers. Yet operation of such systems, in addition to reducing NOx emissions, may also lead to emission of undesirable substances, for example N2O. This paper presents results of experimental tests concerning N2O formation in the selective non-catalytic NOx emission reduction process (SNCR in a stoker boiler (WR 25 type. Obtained results lead to an unambiguous conclusion that there is a dependency between the NOx and N2O concentrations in the exhaust gas when SNCR process is carried out in a coal-fired stoker boiler. Fulfilling new emission standards in the analysed equipment will require 40–50% reduction of NOx concentration. It should be expected that in such a case the N2O emission will be approximately 55–60 mg/m3, with the NOx to N2O conversion factor of about 40%.

  10. Effect of process parameters and injector position on the efficiency of NOx reduction by selective non catalytic reduction technique

    International Nuclear Information System (INIS)

    Hamid, A.; Mehmood, M.A.; Irfan, N.; Javed, M.T.; Waheed, K.

    2009-01-01

    An experimental investigation has been performed to study the effect of atomizer pressure dilution of the reducing reagent and the injector position on the efficiency or the NOx reduction by a selective non-catalytic reduction technique using urea as a reducing agent. Experiments were performed with a flow reactor in which flue gas was generated by the combustion of methane in air at stoichiometric amount of oxygen and the desired levels of initial NOx (400-450 ppm) were achieved by doping the flame with ammonia. The work was directed to investigate the effect of atomizer pressure, dilution of urea reagent and the injector position. The atomizer pressure was varied from 1 to 3bar and 20-25% increase in efficiency was observed by decreasing the pressure. Effect of dilution of urea solution was investigated by varying the strength of the solution from the 8 to 32% and 40-45% increase in the efficiency was observed. Effects of injector position was investigated by injecting the urea solution both in co current and counter current direction of the flue gases and 20-25% increase in the efficiency was observed in counter current direction. (author)

  11. Mixed phase evaporation source

    International Nuclear Information System (INIS)

    1975-01-01

    Apparatus for reducing convection current heat loss in electron beam evaporator is described. A material to be evaporated (evaporant) is placed in the crucible of an electron beam evaporation source along with a porous mass formed of a powdered or finely divided solid to act as an impedance to convection currents. A feed system is employed to replenish the supply of evaporant as it is vaporized

  12. Lake Nasser evaporation reduction study

    Directory of Open Access Journals (Sweden)

    Hala M.I. Ebaid

    2010-10-01

    Full Text Available This study aims to evaluate the reduction of evaporation of Lake Nasser’s water caused by disconnecting (fully or partially some of its secondary channels (khors. This evaluation integrates remote sensing, Geographic Information System (GIS techniques, aerodynamic principles, and Landsat7 ETM+ images. Three main procedures were carried out in this study; the first derived the surface temperature from Landsat thermal band; the second derived evaporation depth and approximate evaporation volume for the entire lake, and quantified evaporation loss to the secondary channels’ level over one month (March by applied aerodynamic principles on surface temperature of the raster data; the third procedure applied GIS suitability analysis to determine which of these secondary channels (khors should be disconnected. The results showed evaporation depth ranging from 2.73 mm/day at the middle of the lake to 9.58 mm/day at the edge. The evaporated water-loss value throughout the entire lake was about 0.86 billion m3/month (March. The analysis suggests that it is possible to save an approximate total evaporation volume loss of 19.7 million m3/month (March, and thus 2.4 billion m3/year, by disconnecting two khors with approximate construction heights of 8 m and 15 m. In conclusion, remote sensing and GIS are useful for applications in remote locations where field-based information is not readily available and thus recommended for decision makers remotely planning in water conservation and management.

  13. Effect of thermal annealing on structural properties of SrGa2S4:Ce thin films prepared by flash evaporation

    International Nuclear Information System (INIS)

    Gambarov, E.F.; Bayramov, A.I.

    2009-01-01

    In the present report the preparation technology and structural characterization of Ce 3 +activated SrGa 2 S 4 thin films are given. SrGa 2 S 4 : e thin films are prepared by so called flash evaporation which is simple and inexpensive method for thin film deposition. X-ray diffraction shows that the as deposited films exhibit amorphous behavior, but after annealing in H S stream, the polycrystalline one. EPMA results indicate nearly stoichiometric composition of the thin films

  14. Electrical and optical properties of thermally-evaporated thin films from A2[TiO(C2O4)2] (A = K, PPh4) and 1,8-dihydroxyanthraquinone

    International Nuclear Information System (INIS)

    Carbia-Ruelas, E.; Sanchez-Vergara, M.E.; Garcia-Montalvo, V.; Morales-Saavedra, O.G.; Alvarez-Bada, J.R.

    2011-01-01

    In this work, the synthesis of molecular materials formed from A 2 [TiO(C 2 O 4 ) 2 ] (A = K, PPh4) and 1,8 dihydroxyanthraquinone is reported. The synthesized materials were characterized by atomic force microscopy (AFM), infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. IR spectroscopy showed that the molecular-material thin-films, deposited by vacuum thermal evaporation, exhibit the same intra-molecular vibration modes as the starting powders, which suggests that the thermal evaporation process does not alter the initial chemical structures. Electrical transport properties were studied by dc conductivity measurements. The electrical activation energies of the complexes, which were in the range of 0.003-1.16 eV, were calculated from Arrhenius plots. Optical absorption studies in the wavelength range of 190-1090 nm at room temperature showed that the optical band gaps of the thin films were around 1.9-2.3 eV for direct transitions Eg d . The cubic NLO effects were substantially enhanced for materials synthesized from K 2 [TiO(C 2 O 4 ) 2 ], where χ (3) (-3ω; ω, ω, ω) values in the promising range of 10 -12 esu have been evaluated.

  15. Electrical and optical properties of thermally-evaporated thin films from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh{sub 4}) and 1,8-dihydroxyanthraquinone

    Energy Technology Data Exchange (ETDEWEB)

    Carbia-Ruelas, E. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Sanchez-Vergara, M.E., E-mail: elena.sanchez@anahuac.mx [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Garcia-Montalvo, V. [Instituto de Quimica, Universidad Nacional Autonoma de Mexico. Circuito Exterior, Ciudad Universitaria, 04510, Mexico, D. F (Mexico); Morales-Saavedra, O.G. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM. A. P. 70-186, Coyoacan, 04510, Mexico, D. F (Mexico); Alvarez-Bada, J.R. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)

    2011-02-01

    In this work, the synthesis of molecular materials formed from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh4) and 1,8 dihydroxyanthraquinone is reported. The synthesized materials were characterized by atomic force microscopy (AFM), infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. IR spectroscopy showed that the molecular-material thin-films, deposited by vacuum thermal evaporation, exhibit the same intra-molecular vibration modes as the starting powders, which suggests that the thermal evaporation process does not alter the initial chemical structures. Electrical transport properties were studied by dc conductivity measurements. The electrical activation energies of the complexes, which were in the range of 0.003-1.16 eV, were calculated from Arrhenius plots. Optical absorption studies in the wavelength range of 190-1090 nm at room temperature showed that the optical band gaps of the thin films were around 1.9-2.3 eV for direct transitions Eg{sub d}. The cubic NLO effects were substantially enhanced for materials synthesized from K{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}], where {chi}{sup (3)} (-3{omega}; {omega}, {omega}, {omega}) values in the promising range of 10{sup -12} esu have been evaluated.

  16. Fragment library screening identifies hits that bind to the non-catalytic surface of Pseudomonas aeruginosa DsbA1

    Science.gov (United States)

    Headey, Stephen J.; Vazirani, Mansha; Shouldice, Stephen R.; Coinçon, Mathieu; Tay, Stephanie; Morton, Craig J.; Simpson, Jamie S.; Martin, Jennifer L.

    2017-01-01

    At a time when the antibiotic drug discovery pipeline has stalled, antibiotic resistance is accelerating with catastrophic implications for our ability to treat bacterial infections. Globally we face the prospect of a future when common infections can once again kill. Anti-virulence approaches that target the capacity of the bacterium to cause disease rather than the growth or survival of the bacterium itself offer a tantalizing prospect of novel antimicrobials. They may also reduce the propensity to induce resistance by removing the strong selection pressure imparted by bactericidal or bacteriostatic agents. In the human pathogen Pseudomonas aeruginosa, disulfide bond protein A (PaDsbA1) plays a central role in the oxidative folding of virulence factors and is therefore an attractive target for the development of new anti-virulence antimicrobials. Using a fragment-based approach we have identified small molecules that bind to PaDsbA1. The fragment hits show selective binding to PaDsbA1 over the DsbA protein from Escherichia coli, suggesting that developing species-specific narrow-spectrum inhibitors of DsbA enzymes may be feasible. Structures of a co-complex of PaDsbA1 with the highest affinity fragment identified in the screen reveal that the fragment binds on the non-catalytic surface of the protein at a domain interface. This biophysical and structural data represent a starting point in the development of higher affinity compounds, which will be assessed for their potential as selective PaDsbA1 inhibitors. PMID:28346540

  17. Non-ionic Surfactants and Non-Catalytic Protein Treatment on Enzymatic Hydrolysis of Pretreated Creeping Wild Ryegrass

    Science.gov (United States)

    Zheng, Yi; Pan, Zhongli; Zhang, Ruihong; Wang, Donghai; Jenkins, Bryan

    Our previous research has shown that saline Creeping Wild Ryegrass (CWR), Leymus triticoides, has a great potential to be used for bioethanol production because of its high fermentable sugar yield, up to 85% cellulose conversion of pretreated CWR. However, the high cost of enzyme is still one of the obstacles making large-scale lignocellulosic bioethanol production economically difficult. It is desirable to use reduced enzyme loading to produce fermentable sugars with high yield and low cost. To reduce the enzyme loading, the effect of addition of non-ionic surfactants and non-catalytic protein on the enzymatic hydrolysis of pretreated CWR was investigated in this study. Tween 20, Tween 80, and bovine serum albumin (BSA) were used as additives to improve the enzymatic hydrolysis of dilute sulfuric-acid-pretreated CWR. Under the loading of 0.1 g additives/g dry solid, Tween 20 was the most effective additive, followed by Tween 80 and BSA. With the addition of Tween 20 mixed with cellulase loading of 15 FPU/g cellulose, the cellulose conversion increased 14% (from 75 to 89%), which was similar to that with cellulase loading of 30 FPU/g cellulose and without additive addition. The results of cellulase and BSA adsorption on the Avicel PH101, pretreated CWR, and lignaceous residue of pretreated CWR support the theory that the primary mechanism behind the additives is prevention of non-productive adsorption of enzymes on lignaceous material of pretreated CWR. The addition of additives could be a promising technology to improve the enzymatic hydrolysis by reducing the enzyme activity loss caused by non-productive adsorption.

  18. Potential for visible plume formation at a coal-fired boiler using ammonia injection for non-catalytic NOx control

    International Nuclear Information System (INIS)

    Hess, T.

    1993-01-01

    Circulating fluidized bed boilers utilizing ammonia injection for non-catalytic NO x reduction have been highly successful in reducing NO x emissions to very low levels. However, one limitation on this technology is the potential for the formation of visible plumes. One plant, with uncontrolled NO x of about 190 ppm, reduces NO x concentrations to the 20-25 ppm range by injecting ammonia in the boiler's cyclones. However, infrequent, short-lived, white, detached plumes have been noted extending for short distances downwind of the stack. Because unreacted ammonia is present in the flue gas along with HCl from coal combustion, the formation of solid NH 4 Cl in the atmosphere was suspected to be the most likely cause of the visible plume. Simple thermodynamic calculations predict the formation of solid ammonium chloride very soon after the flue gas mixes with cooler ambient air and plume optical density calculations are in reasonable agreement with observed plume density. Stack testing and other tests have been conducted during both plume and non-plume events to confirm that NH 4 Cl formation is the most likely cause of the capacity. As presented in this paper, the test data and theoretical calculations indicate that a visible plume may be expected when as little as 5 ppm of ammonia and HCl are present in the flue gas, depending on observation conditions. Analyses of fuel samples taken during stack tests show about 40% of the chlorine in the low chloride coal fired, typically less than 0.04%, is released from the stack as HCl. Ammonia slip is somewhat variable depending on combustion conditions in the boiler and the temperature at the ammonia injection points

  19. A non-catalytic N-terminal domain negatively influences the nucleotide exchange activity of translation elongation factor 1Bα.

    Science.gov (United States)

    Trosiuk, Tetiana V; Shalak, Vyacheslav F; Szczepanowski, Roman H; Negrutskii, Boris S; El'skaya, Anna V

    2016-02-01

    Eukaryotic translation elongation factor 1Bα (eEF1Bα) is a functional homolog of the bacterial factor EF-Ts, and is a component of the macromolecular eEF1B complex. eEF1Bα functions as a catalyst of guanine nucleotide exchange on translation elongation factor 1A (eEF1A). The C-terminal domain of eEF1Bα is necessary and sufficient for its catalytic activity, whereas the N-terminal domain interacts with eukaryotic translation elongation factor 1Bγ (eEF1Bγ) to form a tight complex. However, eEF1Bγ has been shown to enhance the catalytic activity of eEF1Bα attributed to the C-terminal domain of eEF1Bα. This suggests that the N-terminal domain of eEF1Bα may in some way influence the guanine nucleotide exchange process. We have shown that full-length recombinant eEF1Bα and its truncated forms are non-globular proteins with elongated shapes. Truncation of the N-terminal domain of eEF1Bα, which is dispensable for catalytic activity, resulted in acceleration of the rate of guanine nucleotide exchange on eEF1A compared to full-length eEF1Bα. A similar effect on the catalytic activity of eEF1Bα was observed after its interaction with eEF1Bγ. We suggest that the non-catalytic N-terminal domain of eEF1Bα may interfere with eEF1A binding to the C-terminal catalytic domain, resulting in a decrease in the overall rate of the guanine nucleotide exchange reaction. Formation of a tight complex between the eEF1Bγ and eEF1Bα N-terminal domains abolishes this inhibitory effect. © 2015 FEBS.

  20. Drop evaporation and triple line dynamics

    Science.gov (United States)

    Sobac, Benjamin; Brutin, David; Gavillet, Jerome; Université de Provence Team; Cea Liten Team

    2011-03-01

    Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop deposited on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (PTFE, SiOx, SiOc and CF), the influence of the dynamic of the triple line on the evaporation process. The experiment consists in analyzing simultaneously the motion of the triple line, the kinetics of evaporation, the internal thermal motion and the heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamics of the evaporative heat flux appears clearly different depending of the motion of the triple line

  1. Synthesis, structure and optical properties of thin films from GeS{sub 2}–In{sub 2}S{sub 3} system deposited by thermal co-evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, R., E-mail: rossen@iomt.bas.bg [Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 109, 1113 Sofia (Bulgaria); Petkov, K. [Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 109, 1113 Sofia (Bulgaria); Kincl, M. [Institute of Macromolecular Chemistry of Czech Academy of Science, Heyrovsky sq. 2, 162 06 Prague 6 (Czech Republic); Černošková, E. [Faculty of Chemical Technology, University of Pardubice, Studentská 84, 532 10 Pardubice (Czech Republic); Vlček, Mil.; Tichý, L. [Institute of Macromolecular Chemistry of Czech Academy of Science, Heyrovsky sq. 2, 162 06 Prague 6 (Czech Republic)

    2014-05-02

    This paper deals with the properties of the glasses and thin films from multi-component chalcogenide prepared by co-evaporation technique. The thin chalcogenide layers from GeS{sub 2}–In{sub 2}S{sub 3} system were deposited by thermal co-evaporation of GeS{sub 2} and In{sub 2}S{sub 3}. Using X-ray microanalysis it was found that the film compositions are closed to the expected ones. X-ray diffraction analysis shows that the thin films deposited by co-evaporation are amorphous. The refractive index, n and the optical band gap, E{sub g}{sup opt} were calculated from the transmittance and reflectance spectra. The thin film's structure was investigated by infrared spectroscopy. It was found that the photo-induced optical changes decrease with increase of indium content while significant thermo-induced changes in the optical properties and structure were observed at 14 at.% indium. The infrared spectra demonstrated high transmittance of the thin films in the range 4000–500 cm{sup −1}. The far-infrared spectra indicated that the indium participates in the glass network of the layers from Ge–S–In system in four coordinated InS{sub 4/2}{sup −} tetrahedral and six-coordinated InS{sub 6/2}{sup 3−} octahedral units. The changes in infrared spectra after annealing of the thin films evidence an increase of population of ethane-like S{sub 3}Ge–GeS{sub 3} units and/or structural or phase change of indium contain units. - Highlights: • The thin layers from GeS{sub 2}–In{sub 2}S{sub 3} system were deposited by thermal co-evaporation. • The photo-induced optical changes decrease with increase of indium content. • The thermo-induced changes in the optical properties and structure were investigated. • The structure of the thin films was investigated by infrared spectroscopy.

  2. Evaporator Cleaning Studies

    International Nuclear Information System (INIS)

    Wilmarth, W.R.

    1999-01-01

    Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning

  3. Vapor-based interferometric measurement of local evaporation rate and interfacial temperature of evaporating droplets.

    Science.gov (United States)

    Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

    2014-03-04

    The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory.

  4. Evaporation and Climate Change

    NARCIS (Netherlands)

    Brandsma, T.

    1993-01-01

    In this article the influence of climate change on evaporation is discussed. The emphasis is on open water evaporation. Three methods for calculating evaporation are compared considering only changes in temperature and factors directly dependent on temperature. The Penman-method is used to

  5. Thermocapillary flow about an evaporating meniscus

    Science.gov (United States)

    Schmidt, G. R.; Chung, T. J.

    1992-01-01

    The steady motion and thermal behavior of an evaporating superheated liquid in a small cavity bounded by isothermal sidewalls is examined. Scaling analyses and a two-dimensional finite element model are used to investigate the influence of thermocapillarity, buoyancy, and temperature-dependent mass flux on flowfield, interfacial heat transfer, and meniscus morphology. Numerical investigations indicate the existence of two counter-rotating cells symmetric about the cavity center. Results also show that evaporation tends to counteract this circulation by directing flow toward the hotter sidewalls. Although thermocapillarity and evaporation yield different flowfield distributions, both effects tend to increase interfacial temperature and heat transfer.

  6. Preparation and optical and electrical evaluation of bulk SiO2 sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    International Nuclear Information System (INIS)

    Sanchez Vergara, Maria Elena; Morales-Saavedra, Omar G.; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto; Ortiz Rebollo, Armando

    2009-01-01

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E g ) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO 2 sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively

  7. Preparation and optical and electrical evaluation of bulk SiO{sub 2} sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, Maria Elena [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Morales-Saavedra, Omar G. [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico)], E-mail: omar.morales@ccadet.unam.mx; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico); Ortiz Rebollo, Armando [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, IIM-UNAM, A.P. 70-360, Coyoacan, 04510 Mexico, D.F. (Mexico)

    2009-02-25

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E{sub g}) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO{sub 2} sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively.

  8. A Robust CuCr2O4/SiO2 Composite Photothermal Material with Underwater Black Property and Extremely High Thermal Stability for Solar-Driven Water Evaporation

    KAUST Repository

    Shi, Yusuf

    2017-12-27

    The design and fabrication of efficient photothermal materials is the key issue in solar-driven water evaporation. In this work, a robust CuCr2O4/SiO2 composite membrane with outstanding solar-driven water evaporation performance (1.32 kg m−2 h−1) under one sun irradiation is rationally designed and synthesized by using quartz glass fibrous membrane as supporting matrix and stable CuCr2O4 particles as the active light absorber. Instead of coating a separate layer on top of the support, the CuCr2O4 particles are evenly distributed inside the matrix, which endows the membrane with great mechanical strength and excellent wear and abrasion resistance. The highly porous composite survives 6 atm pressure and retains its performance even after 75% of the membrane is removed by sandpaper. This work also looks into a generally overlooked aspect of wet versus dry state of photothermal material and its implications. Interestingly, the composite possesses a gray color with a high reflectance in dry state but turns into deep black with a low reflectance in wet state due to the decreased subsurface scattering and strong NIR light absorbance of water in wet state. This composite material also possesses excellent thermal stability and thermal shock resistance, making it able to be easily recovered by calcination in air or direct burning in fire for contaminants removal. The results demonstrate that this composite is a competitive photothermal material for practical solar distillation and indicate that the optical properties of material in wet state are more relevant to photothermal material screening and optimization for solar distillation.

  9. Microwave heating type evaporator

    International Nuclear Information System (INIS)

    Taura, Masazumi; Nishi, Akio; Morimoto, Takashi; Izumi, Jun; Tamura, Kazuo; Morooka, Akihiko.

    1987-01-01

    Purpose: To prevent evaporization stills against corrosion due to radioactive liquid wastes. Constitution: Microwaves are supplied from a microwave generator by way of a wave guide tube and through a microwave permeation window to the inside of an evaporatization still. A matching device is attached to the wave guide tube for transmitting the microwaves in order to match the impedance. When the microwaves are supplied to the inside of the evaporization still, radioactive liquid wastes supplied from a liquid feed port by way of a spray tower to the inside of the evaporization still is heated and evaporated by the induction heating of the microwaves. (Seki, T.)

  10. Structure and properties of ZnSxSe1-x thin films deposited by thermal evaporation of ZnS and ZnSe powder mixtures

    Science.gov (United States)

    Valeev, R. G.; Romanov, E. A.; Vorobiev, V. L.; Mukhgalin, V. V.; Kriventsov, V. V.; Chukavin, A. I.; Robouch, B. V.

    2015-02-01

    Interest to ZnSxSe1-x alloys is due to their band-gap tunability varying S and Se content. Films of ZnSxSe1-x were grown evaporating ZnS and ZnSe powder mixtures onto SiO2, NaCl, Si and ITO substrates using an original low-cost method. X-ray diffraction patterns and Raman spectroscopy, show that the lattice structure of these films is cubic ZnSe-like, as S atoms replace Se and film compositions have their initial S/Se ratio. Optical absorption spectra show that band gap values increase from 2.25 to 3 eV as x increases, in agreement with the literature. Because S atomic radii are smaller than Se, EXAFS spectra confirm that bond distances and Se coordination numbers decrease as the Se content decreases. The strong deviation from linearity of ZnSe coordination numbers in the ZnSxSe1-x indicate that within this ordered crystal structure strong site occupation preferences occur in the distribution of Se and S ions. The behavior is quantitatively confirmed by the strong deviation from the random Bernoulli distribution of the three sight occupation preference coefficients of the strained tetrahedron model. Actually, the ternary ZnSxSe1-x system is a bi-binary (ZnS+ZnSe) alloy with evanescent formation of ternary configurations throughout the x-range.

  11. Evaporation of nanofluid droplet on heated surface

    Directory of Open Access Journals (Sweden)

    Yeung Chan Kim

    2015-04-01

    Full Text Available In this study, an experiment on the evaporation of nanofluid sessile droplet on a heated surface was conducted. A nanofluid of 0.5% volumetric concentration mixed with 80-nm-sized CuO powder and pure water were used for experiment. Droplet was applied to the heated surface, and images of the evaporation process were obtained. The recorded images were analyzed to find the volume, diameter, and contact angle of the droplet. In addition, the evaporative heat transfer coefficient was calculated from experimental result. The results of this study are summarized as follows: the base diameter of the droplet was maintained stably during the evaporation. The measured temperature of the droplet was increased rapidly for a very short time, then maintained constantly. The nanofluid droplet was evaporated faster than the pure water droplet under the experimental conditions of the same initial volume and temperature, and the average evaporative heat transfer coefficient of the nanofluid droplet was higher than that of pure water. We can consider the effects of the initial contact angle and thermal conductivity of nanofluid as the reason for this experimental result. However, the effect of surface roughness on the evaporative heat transfer of nanofluid droplet appeared unclear.

  12. Evaporation, Boiling and Bubbles

    Science.gov (United States)

    Goodwin, Alan

    2012-01-01

    Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

  13. Vacuum evaporation of pure metals

    OpenAIRE

    Safarian, Jafar; Engh, Thorvald Abel

    2013-01-01

    Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision...

  14. Evaporation in hydrology and meteorology

    OpenAIRE

    Brandsma, T.

    1990-01-01

    In this paper the role of evaporation in hydrology and meteorology is discussed, with the emphasis on hydrology. The basic theory of evaporation is given and methods to determine evaporation are presented. Some applications of evaporation studies in literature are given in order to illustrate the theory. Further, special conditions in evaporation are considered, followed by a fotmulation of the difficulties in determining evaporation, The last part of the paper gives a short discussion about ...

  15. Evaporation under vacuum condition

    International Nuclear Information System (INIS)

    Mizuta, Satoshi; Shibata, Yuki; Yuki, Kazuhisa; Hashizume, Hidetoshi; Toda, Saburo; Takase, Kazuyuki; Akimoto, Hajime

    2000-01-01

    In nuclear fusion reactor design, an event of water coolant ingress into its vacuum vessel is now being considered as one of the most probable accidents. In this report, the evaporation under vacuum condition is evaluated by using the evaporation model we have developed. The results show that shock-wave by the evaporation occurs whose behavior strongly depends on the initial conditions of vacuum. And in the case of lower initial pressure and temperature, the surface temp finally becomes higher than other conditions. (author)

  16. High-yield production of biodiesel by non-catalytic supercritical methanol transesterification of crude castor oil (Ricinus communis)

    International Nuclear Information System (INIS)

    Román-Figueroa, Celián; Olivares-Carrillo, Pilar; Paneque, Manuel; Palacios-Nereo, Francisco Javier; Quesada-Medina, Joaquín

    2016-01-01

    The synthesis of biodiesel from crude castor oil in a catalyst-free process using supercritical methanol in a batch reactor was investigated, studying the evolution of intermediate products as well as the conversion of triglycerides and the yield of FAMEs (fatty acid methyl esters) (biodiesel). Experiments were carried out in a temperature range of 250–350 °C (10–43 MPa) at reaction times of 15–90 min for a methanol-to-oil molar ratio of 43:1. Maintaining thermal stability of biodiesel is one of the most important concerns in high-yield supercritical biodiesel production. Hence, thermal decomposition degree of FAMEs was also investigated in different reaction conditions. The maximum yield of FAMEs (96.5%) was obtained at 300 °C (21 MPa) and 90 min. Under these conditions, the conversion of triglycerides was complete, the yield of intermediate products was low (3.29 and 1.41% for monoglycerides and diglycerides, respectively), and thermal decomposition of FAMEs did not occur. The maximum degree of thermal decomposition (80.9%) was produced at 350 °C (43 MPa) and 90 min. Methyl ricinoleate, whose fatty acid chain was the most abundant (88.09 mol%) in castor oil, was very unstable above 300 °C and 60 min, leading to low yields of FAMEs under these conditions. - Highlights: • Supercritical synthesis of biodiesel from crude castor oil was investigated. • Supercritical methanolysis of crude castor oil reached a high yield of FAMEs. • Ricinoleic acid methyl ester was very unstable above 300 °C and 60 min reaction.

  17. Waste Feed Evaporation Physical Properties Modeling

    International Nuclear Information System (INIS)

    Daniel, W.E.

    2003-01-01

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software

  18. CAPSULE REPORT: EVAPORATION PROCESS

    Science.gov (United States)

    Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....

  19. Boilers, evaporators, and condensers

    International Nuclear Information System (INIS)

    Kakac, S.

    1991-01-01

    This book reports on the boilers, evaporators and condensers that are used in power plants including nuclear power plants. Topics included are forced convection for single-phase side heat exchangers, heat exchanger fouling, industrial heat exchanger design, fossil-fuel-fired boilers, once through boilers, thermodynamic designs of fossil fuel-first boilers, evaporators and condensers in refrigeration and air conditioning systems (with respect to reducing CFC's) and nuclear steam generators

  20. Temperature studies of optical parameters of (Ag3AsS3)0.6(As2S3)0.4 thin films prepared by rapid thermal evaporation and pulse laser deposition

    Science.gov (United States)

    Studenyak, I. P.; Kutsyk, M. M.; Buchuk, M. Yu.; Rati, Y. Y.; Neimet, Yu. Yu.; Izai, V. Yu.; Kökényesi, S.; Nemec, P.

    2016-02-01

    (Ag3AsS3)0.6(As2S3)0.4 thin films were deposited using rapid thermal evaporation (RTE) and pulse laser deposition (PLD) techniques. Ag-enriched micrometre-sized cones (RTE) and bubbles (PLD) were observed on the thin film surface. Optical transmission spectra of the thin films were studied in the temperature range 77-300 K. The Urbach behaviour of the optical absorption edge in the thin films due to strong electron-phonon interaction was observed, the main parameters of the Urbach absorption edge were determined. Temperature dependences of the energy position of the exponential absorption edge and the Urbach energy are well described in the Einstein model. Dispersion and temperature dependences of refractive indices were analysed; a non-linear increase of the refractive indices with temperature was revealed. Disordering processes in the thin films were studied and compared with bulk composites, the differences between the thin films prepared by RTE and PLD were analysed.

  1. An investigation of the insertion of the cations H{sup +}, Na{sup +}, K{sup +} on the electrochromic properties of the thermally evaporated WO{sub 3} thin films grown at different substrate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Panchal, C.J., E-mail: cjpanchal_msu@yahoo.com [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Mehta, P.K. [Physics Department, Faculty of Science, M.S. University of Baroda, Vadodara 390002, Gujarat (India)

    2010-11-01

    The phenomenon of electrochromism in tungsten trioxide (WO{sub 3}) thin films has recently attained considerable interest due to their enormous applications in inorganic thin film electrochromic devices. We have investigated the compositional, optical, and electrochromic properties of the WO{sub 3} thin films grown at different substrate temperatures by the thermal evaporation of WO{sub 3} powder. The thin films were characterized using X-ray diffraction (XRD), X-ray photo-emission spectroscopy (XPS), and electrochemical techniques. The XPS analysis suggested that the oxygen to tungsten (O/W) ratio decreases, i.e., the oxygen deficiency increases, on increasing the substrate temperature up to 500 deg. C. The electrochemical analysis provided a comparative study of the coloration efficiency (CE) of the WO{sub 3} thin films intercalated with three different ions viz. H{sup +}, Na{sup +}, and K{sup +}. The effect of the variation of the substrate temperature on the CE and the switching time have also been investigated for the WO{sub 3} thin films intercalated with H{sup +} ions; the thin films deposited at RT and intercalated with H{sup +} ions are found to possess adequate electrochromic properties viz. CE and switching time from device point of view.

  2. Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) yields better Hydrolytical Stability of Biocompatible SiOx Thin Films on Implant Alumina Ceramics compared to Rapid Thermal Evaporation Physical Vapor Deposition (PVD).

    Science.gov (United States)

    Böke, Frederik; Giner, Ignacio; Keller, Adrian; Grundmeier, Guido; Fischer, Horst

    2016-07-20

    Densely sintered aluminum oxide (α-Al2O3) is chemically and biologically inert. To improve the interaction with biomolecules and cells, its surface has to be modified prior to use in biomedical applications. In this study, we compared two deposition techniques for adhesion promoting SiOx films to facilitate the coupling of stable organosilane monolayers on monolithic α-alumina; physical vapor deposition (PVD) by thermal evaporation and plasma enhanced chemical vapor deposition (PE-CVD). We also investigated the influence of etching on the formation of silanol surface groups using hydrogen peroxide and sulfuric acid solutions. The film characteristics, that is, surface morphology and surface chemistry, as well as the film stability and its adhesion properties under accelerated aging conditions were characterized by means of X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and tensile strength tests. Differences in surface functionalization were investigated via two model organosilanes as well as the cell-cytotoxicity and viability on murine fibroblasts and human mesenchymal stromal cells (hMSC). We found that both SiOx interfaces did not affect the cell viability of both cell types. No significant differences between both films with regard to their interfacial tensile strength were detected, although failure mode analyses revealed a higher interfacial stability of the PE-CVD films compared to the PVD films. Twenty-eight day exposure to simulated body fluid (SBF) at 37 °C revealed a partial delamination of the thermally deposited PVD films whereas the PE-CVD films stayed largely intact. SiOx layers deposited by both PVD and PE-CVD may thus serve as viable adhesion-promoters for subsequent organosilane coupling agent binding to α-alumina. However, PE-CVD appears to be favorable for long-term direct film exposure to aqueous

  3. Life cycle assessment of selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator

    DEFF Research Database (Denmark)

    Møller, Jacob; Munk, Bjarne; Crillesen, Kim

    2011-01-01

    Selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator was investigated using LCA. The relationship between NOx-cleaning and ammonia dosage was measured at the plant. Un-reacted ammonia – the ammonia slip – leaving the flue-gas cleaning system......-cleaning efficiency, the fate of the ammonia slip as well as the environmental impact from ammonia production, the potential acidification and nutrient enrichment from NOx-cleaning was calculated as a function of ammonia dosage. Since the exact fate of the ammonia slip could not be measured directly, a number...... of scenarios were set up ranging from “best case” with no ammonia from the slip ending up in the environment to “worst case” where all the ammonia slip eventually ended up in the environment and contributed to environmental pollution. In the “best case” scenario the highest ammonia dosage was most beneficial...

  4. Numerical simulation of droplet evaporation between two circular plates

    International Nuclear Information System (INIS)

    Bam, Hang Jin; Son, Gi Hun

    2015-01-01

    Numerical simulation is performed for droplet evaporation between two circular plates. The flow and thermal characteristics of the droplet evaporation are numerically investigated by solving the conservation equations of mass, momentum, energy and mass fraction in the liquid and gas phases. The liquid-gas interface is tracked by a sharp-interface level-set method which is modified to include the effects of evaporation at the liquid-gas interface and contact angle hysteresis at the liquid-gas-solid contact line. An analytical model to predict the droplet evaporation is also developed by simplifying the mass and vapor fraction equations in the gas phase. The numerical results demonstrate that the 1-D analytical prediction is not applicable to the high rate evaporation process. The effects of plate gap and receding contact angle on the droplet evaporation are also quantified.

  5. Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

    Science.gov (United States)

    Chen, Pin; Harmand, Souad; Ouenzerfi, Safouene; Schiffler, Jesse

    2017-06-15

    The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

  6. Evaporation in hydrology and meteorology

    NARCIS (Netherlands)

    Brandsma, T.

    1990-01-01

    In this paper the role of evaporation in hydrology and meteorology is discussed, with the emphasis on hydrology. The basic theory of evaporation is given and methods to determine evaporation are presented. Some applications of evaporation studies in literature are given in order to illustrate the

  7. Evaporative oxidation treatability test report

    International Nuclear Information System (INIS)

    1995-04-01

    In 1992, Congress passed the Federal Facilities Compliance Act that requires the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with the Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). In response to the need for mixed-waste treatment capacity where available off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed wastes with treatment options and develop a strategy for treatment of its mixed wastes. DOE-AL manages operations at nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment capacity to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste not only must address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. On the basis of recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (GJPO) are evaporative oxidation, thermal desorption, and treated wastewater evaporation. Rust Geotech, the DOE-GJPO prime contractor, was assigned to design and fabricate mobile treatment units (MTUs) for these three technologies and to deliver the MTUs to selected DOE-AL sites. To conduct treatability tests at the GJPO, Rust leased a pilot-scale evaporative oxidation unit from the Clemson Technical Center (CTC), Anderson, South Carolina. The purpose of this report is to document the findings and results of tests performed using this equipment

  8. Water evaporation in silica colloidal deposits.

    Science.gov (United States)

    Peixinho, Jorge; Lefèvre, Grégory; Coudert, François-Xavier; Hurisse, Olivier

    2013-10-15

    The results of an experimental study on the evaporation and boiling of water confined in the pores of deposits made of mono-dispersed silica colloidal micro-spheres are reported. The deposits are studied using scanning electron microscopy, adsorption of nitrogen, and adsorption of water through attenuated total reflection-infrared spectroscopy. The evaporation is characterized using differential scanning calorimetry and thermal gravimetric analysis. Optical microscopy is used to observe the patterns on the deposits after evaporation. When heating at a constant rate and above boiling temperature, the release of water out of the deposits is a two step process. The first step is due to the evaporation and boiling of the surrounding and bulk water and the second is due to the desorption of water from the pores. Additional experiments on the evaporation of water from membranes having cylindrical pores and of heptane from silica deposits suggest that the second step is due to the morphology of the deposits. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Modeling black hole evaporation

    CERN Document Server

    Fabbri, Alessandro

    2005-01-01

    The scope of this book is two-fold: the first part gives a fully detailed and pedagogical presentation of the Hawking effect and its physical implications, and the second discusses the backreaction problem, especially in connection with exactly solvable semiclassical models that describe analytically the black hole evaporation process. The book aims to establish a link between the general relativistic viewpoint on black hole evaporation and the new CFT-type approaches to the subject. The detailed discussion on backreaction effects is also extremely valuable.

  10. Systematics of evaporation

    International Nuclear Information System (INIS)

    Klots, C.E.

    1991-01-01

    Beginning with rather basic principles, general relations are obtained for evaporative rate constants. These are established both as a function of energy and of temperature. In parallel with this, expressions are developed for the kinetic energy distribution of the separating species. Explicit evaluation of the rate constants in the case of 'chemical' evaporation from an entity containing n monomeric units yields as a typical result k(T)(s -1 )=3.10 13 n 2/3 exp[6/n 1/3 ]exp(-ΔE a (n)/k B T). Experimental evidence in support of this relation is cited. Applications to thermionic emission are also noted. (orig.)

  11. Multilayer composite material and method for evaporative cooling

    Science.gov (United States)

    Buckley, Theresa M. (Inventor)

    2002-01-01

    A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.

  12. Investigating performance of microchannel evaporators for automobile air conditioning with different port structures

    Directory of Open Access Journals (Sweden)

    Guoliang Zhou

    2017-08-01

    Full Text Available Microchannel evaporator has been widely applied in automobile air conditioning, while it faces the problem of refrigerant maldistribution which deteriorates the thermal performance of evaporator. In this study, the performances of microchannel evaporators with different port structures are experimentally investigated for purpose of reducing evaporator pressure drop. Four evaporator samples with different port number and hydraulic diameter are made for this study. The performances of the evaporator samples are tested on a psychometric calorimeter test bench with the refrigerant R-134A at a real automobile air conditioning. The results on the variations of the evaporator pressure drop and evaporator surface temperature distribution are presented and analyzed. By studying the performance of an evaporator, seeking proper port structure is an approach to reduce refrigerant pressure drop as well as improve refrigerant distribution.

  13. Parametric study of thin film evaporation from nanoporous membranes

    Science.gov (United States)

    Wilke, Kyle L.; Barabadi, Banafsheh; Lu, Zhengmao; Zhang, TieJun; Wang, Evelyn N.

    2017-10-01

    The performance and lifetime of advanced electronics are often dictated by the ability to dissipate heat generated within the device. Thin film evaporation from nanoporous membranes is a promising thermal management approach, which reduces the thermal transport distance across the liquid film while also providing passive capillary pumping of liquid to the evaporating interface. In this work, we investigated the dependence of thin film evaporation from nanoporous membranes on a variety of geometric parameters. Anodic aluminum oxide membranes were used as experimental templates, where pore radii of 28-75 nm, porosities of 0.1-0.35, and meniscus locations down to 1 μm within the pore were tested. We demonstrated different heat transfer regimes and observed more than an order of magnitude increase in dissipated heat flux by operating in the pore-level evaporation regime. The pore diameter had little effect on pore-level evaporation performance due to the negligible conduction resistance from the pore wall to the evaporating interface. The dissipated heat flux scaled with porosity as the evaporative area increased. Furthermore, moving the meniscus as little as 1 μm into the pore decreased the dissipated heat flux by more than a factor of two due to the added resistance to vapor escaping the pore. The experimental results elucidate thin film evaporation from nanopores and confirm findings of recent modeling efforts. This work also provides guidance for the design of future thin film evaporation devices for advanced thermal management. Furthermore, evaporation from nanopores is relevant to water purification, chemical separations, microfluidics, and natural processes such as transpiration.

  14. Evaporative cooling in ATLAS - present and future

    CERN Document Server

    Viehhauser, G; The ATLAS collaboration

    2010-01-01

    The ATLAS Inner Detector cooling system is the largest evaporative cooling system used in High Energy Physics today. During the installation and commissioning of this system many lessons had to be learned, but the system is now operating reliably, although it does not achieve all original design specifications in all its circuits. We have re-evaluated the requirements for the cooling system, in particular for the evaporation temperature, over the full ATLAS operational lifetime. We find that the critical requirement is for thermal stability at the end of the operation in the high-radiation environment. To predict this we have developed a simple thermal model of the detector modules which yields analytical expressions to evaluate the results of changes in the operating conditions. After a comparison of the revised requirements and the actual present cooling system performance we will discuss various modifications to the system which will be required for future operation. In parallel we are developing a cooling...

  15. Performance of evaporative condensers

    Energy Technology Data Exchange (ETDEWEB)

    Ettouney, Hisham M.; El-Dessouky, Hisham T.; Bouhamra, Walid; Al-Azmi, Bader

    2001-07-01

    Experimental investigation is conducted to study the performance of evaporative condensers/coolers. The analysis includes development of correlations for the external heat transfer coefficient and the system efficiency. The evaporative condenser includes two finned-tube heat exchangers. The system is designed to allow for operation of a single condenser, two condensers in parallel, and two condensers in series. The analysis is performed as a function of the water-to-air mass flow rate ratio (L/G) and the steam temperature. Also, comparison is made between the performance of the evaporative condenser and same device as an air-cooled condenser. Analysis of the collected data shows that the system efficiency increases at lower L/G ratios and higher steam temperatures. The system efficiency for various configurations for the evaporative condenser varies between 97% and 99%. Lower efficiencies are obtained for the air-cooled condenser, with values between 88% and 92%. The highest efficiency is found for the two condensers in series, followed by two condensers in parallel and then the single condenser. The parallel condenser configuration can handle a larger amount of inlet steam and can provide the required system efficiency and degree of subcooling. The correlation for the system efficiency gives a simple tool for preliminary system design. The correlation developed for the external heat transfer coefficient is found to be consistent with the available literature data. (Author)

  16. Pulse thermal energy transport/storage system

    Science.gov (United States)

    Weislogel, Mark M.

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  17. Forest evaporation models: Relationships between stand growth and evaporation

    CSIR Research Space (South Africa)

    Le Maitre, David C

    1997-06-01

    Full Text Available The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation...

  18. KEPLER PLANETS: A TALE OF EVAPORATION

    Energy Technology Data Exchange (ETDEWEB)

    Owen, James E. [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Wu, Yanqin, E-mail: jowen@cita.utoronto.ca, E-mail: wu@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

    2013-10-01

    Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R{sub ⊕}. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above

  19. KEPLER PLANETS: A TALE OF EVAPORATION

    International Nuclear Information System (INIS)

    Owen, James E.; Wu, Yanqin

    2013-01-01

    Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ⊕ . Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ⊕ and

  20. Flashing evaporation under different pressure levels

    International Nuclear Information System (INIS)

    Liao, Yixiang; Lucas, Dirk; Krepper, Eckhard; Rzehak, Roland

    2013-01-01

    Highlights: • CFD simulation based on two-fluid model for flashing boiling inside a vertical pipe. • Effect of pressure level on the maximum thermal energy available for evaporation. • Effect of presumed bubble size on the onset of flashing as well as evaporation rate. • Effect of pressure level on the critical bubble size that can start stable flashing. • Effect of pressure level on nucleation rate and mechanism. - Abstract: Flashing evaporation of water inside a vertical pipe under four pressure levels is investigated both experimentally and numerically. In the experiment depressurization is realized through a blow-off valve, and the evaporation rate is controlled by the opening rate and degree of the valve. In the CFD simulation phase change is assumed to be caused by thermal heat transfer between steam–water interface and the surrounding water. Consequently, the evaporation rate is determined by heat transfer coefficient, interfacial area density as well as liquid superheat degree. The simulated temporal course of cross-section averaged steam volume fraction is compared with the measured one. It is found that the increasing rate and maximum value of steam volume fraction is over-predicted under low-pressure conditions, which is mainly caused by the neglect of bubble growth in the mono-dispersed simulation. The agreement is notably improved by performing poly-dispersed simulations with the inhomogeneous MUSIG approach (IMUSIG). On the other hand an underestimation of the maximum steam volume fraction is observed in high-pressure cases, since the contribution of nucleation to the total steam generation rate becomes large as the system pressure increases. Reliable models for nucleation rate as well as bubble detachment size are indispensable for reliable predictions. An effect of the system pressure level on the nucleation mechanism is observed in the experiment

  1. Convection-enhanced water evaporation

    OpenAIRE

    B. M. Weon; J. H. Je; C. Poulard

    2011-01-01

    Water vapor is lighter than air; this can enhance water evaporation by triggering vapor convection but there is little evidence. We directly visualize evaporation of nanoliter (2 to 700 nL) water droplets resting on silicon wafer in calm air using a high-resolution dual X-ray imaging method. Temporal evolutions of contact radius and contact angle reveal that evaporation rate linearly changes with surface area, indicating convective (instead of diffusive) evaporation in nanoliter water droplet...

  2. Novel Roles of the Non-catalytic Elements of Yeast Protein-disulfide Isomerase in Its Interplay with Endoplasmic Reticulum Oxidoreductin 1*

    Science.gov (United States)

    Niu, Yingbo; Zhang, Lihui; Yu, Jiaojiao; Wang, Chih-chen; Wang, Lei

    2016-01-01

    The formation of disulfide bonds in the endoplasmic reticulum (ER) of eukaryotic cells is catalyzed by the sulfhydryl oxidase, ER oxidoreductin 1 (Ero1), and protein-disulfide isomerase (PDI). PDI is oxidized by Ero1 to continuously introduce disulfides into substrates, and feedback regulates Ero1 activity by manipulating the regulatory disulfides of Ero1. In this study we find that yeast Ero1p is enzymatically active even with its regulatory disulfides intact, and further activation of Ero1p by reduction of the regulatory disulfides requires the reduction of non-catalytic Cys90-Cys97 disulfide in Pdi1p. The principal client-binding site in the Pdi1p b′ domain is necessary not only for the functional Ero1p-Pdi1p disulfide relay but also for the activation of Ero1p. We also demonstrate by complementary activation assays that the regulatory disulfides in Ero1p are much more stable than those in human Ero1α. These new findings on yeast Ero1p-Pdi1p interplay reveal significant differences from our previously identified mode of human Ero1α-PDI interplay and provide insights into the evolution of the eukaryotic oxidative protein folding pathway. PMID:26846856

  3. Removal of nitrogen compounds from gasification gas by selective catalytic or non-catalytic oxidation; Typpiyhdisteiden poisto kaasutuskaasusta selektiivisellae katalyyttisellae ja ei-katalyyttisellae hapetuksella

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-01

    In gasification reactive nitrogenous compounds are formed from fuel nitrogen, which may form nitrogen oxides in gas combustion. In fluidized bed gasification the most important nitrogenous compound is ammonia (NH{sub 3}). If ammonia could be decomposed to N{sub 2} already before combustion, the emissions if nitrogen oxides could be reduced significantly. One way of increasing the decomposition rate of NH{sub 3} could be the addition of suitable reactants to the gas, which would react with NH{sub 3} and produce N{sub 2}. The aim of this research is to create basic information, which can be used to develop a new method for removal of nitrogen compounds from gasification gas. The reactions of nitrogen compounds and added reactants are studied in reductive atmosphere in order to find conditions, in which nitrogen compounds can be oxidized selectively to N{sub 2}. The project consists of following subtasks: (1) Selective non-catalytic oxidation (SNCO): Reactions of nitrogen compounds and oxidizers in the gas phase, (2) Selective catalytic oxidation (SCO): Reactions of nitrogen compounds and oxidizers on catalytically active surfaces, (3) Kinetic modelling of experimental results in co-operation with the Combustion Chemistry Research Group of Aabo Akademi University. The most important finding has been that NH{sub 3} can be made to react selectively with the oxidizers even in the presence of large amounts of CO and H{sub 2}. Aluminium oxides were found to be the most effective materials promoting selectivity. (author)

  4. Evaporative behavior of carbon with MPD Arc Jet

    Energy Technology Data Exchange (ETDEWEB)

    Sukegawa, Toshio; Madarame, Haruki; Okamoto, Koji [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Using the Magneto-Plasma-Dynamic Arc Jet (MPD Arc Jet) device, the plasma-material interaction during simulated plasma disruption was experimentally investigated. To clarify the effects of the evaporation, the isotropic graphite was used as a target. The thermal conductivity of the isotropic graphite was much higher than that of the pyrolytic graphite, resulting in smaller evaporation. The light intensity distribution during the simulated disruption for the isotropic graphite was quite different from that for the pyrolytic graphite. (author)

  5. Influence of composition on optical and dispersion parameters of thermally evaporated non-crystalline Cd{sub 50}S{sub 50−x}Se{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hassanien, A.S., E-mail: a.s.hassanien@gmail.com [Engineering Mathematics and Physics Dept., Faculty of Engineering (Shoubra), Benha University (Egypt); Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia); Akl, Alaa A. [Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia)

    2015-11-05

    Non-crystalline thin films of chalcogenide Cd{sub 50}S{sub 50−x}Se{sub x} system (30 ≤ x ≤ 50) were obtained by thermal evaporation technique onto a pre-cleaned glass substrate at a vacuum of 8.2 × 10{sup −4} Pa. The deposition rate and film thickness were kept constant at about 8 nm/s and 200 nm, respectively. Amorphous/crystalline nature and chemical composition of films have been checked using X-ray diffraction and energy dispersive X-ray spectroscopy (EDX). Optical properties of thin films were investigated and studied using the corrected transmittance, T(λ) and corrected reflectance, R(λ) measurements. Obtained data reveal that, the indirect optical energy gap (E{sub g}) was decreased from 2.21 to 1.57 eV. On the contrary, Urbach energy (band tail width), E{sub U} was found to be increased from 0.29 to 0.45 eV. This behavior is believed to be associated with the increase of Se-content instead of S-content in the thin films of Cd{sub 50}S{sub 50−x}Se{sub x} system. Chemical bond approach model, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. Optical density, skin depth, extinction coefficient, refractive index and optical conductivity of chalcogenide CdSSe thin films were discussed as functions of Se-content. Using Wemple-DiDomenico single oscillator model, the refractive index dispersion and energy parameters and their dependence on Se content were studied. - Highlights: • Amorphous thin films of thickness 200 nm of Cd{sub 50}S{sub 50−x}Se{sub x} (30 ≤ x ≤ 50) have prepared. • Optical properties, indirect optical energy gap and band tail width were studied. • Chemical bond approach, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. • New data of dispersion refractive index parameters were investigated and discussed.

  6. Studies on dielectric properties, opto-electrical parameters and electronic polarizability of thermally evaporated amorphous Cd{sub 50}S{sub 50−x}Se{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hassanien, Ahmed Saeed, E-mail: a.s.hassanien@gmail.com [Engineering Mathematics and Physics Department, Faculty of Engineering (Shoubra), Benha University (Egypt); Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia)

    2016-06-25

    The objective of this work is to study the influence of the addition of more Se on dielectric properties, opto-electrical parameters and electronic polarizability of amorphous chalcogenide Cd{sub 50}S{sub 50−x}Se{sub x} thin films (30 ≤ x ≤ 50 at%). Thin films of thickness 200 nm were synthesized by vacuum deposition at ≈8.2 × 10{sup −4} Pa. Both refractive index and extinction coefficient were used to obtain all the studied parameters. The high frequency dielectric constant, real and imaginary parts of dielectric constant were discussed. Drude theory was applied to investigate opto-electrical parameters, like optical carrier concentration, optical mobility and optical resistivity. Moreover, other parameters were investigated and studied, e.g. Drude parameters, volume and surface energy loss functions, dielectric loss factor, dielectric relaxation time, complex optical conductivity and electronic polarizability as well as optical electronegativity and third-order nonlinear optical susceptibility. Values of electronic polarizability and nonlinear optical susceptibility were found to be decreased while optical electronegativity increased as Se-content was increased. Increment of Se-content in amorphous Cd{sub 50}S{sub 50−x}Se{sub x} thin films has also led to minimize the energy losses when electromagnetic waves propagate through films as well as optical conductivity and the speed of light increased. The other studied properties and parameters of Cd{sub 50}S{sub 50−x}Se{sub x} films were found to be strongly dependent upon Se-content. - Highlights: • Thermally evaporated amorphous Cd{sub 50}S{sub 50−x}Se{sub x} (30 ≤ x ≤ 50) thin films were deposited. • Refractive index and absorption index were used to determine almost all properties. • Dielectric properties, Drude parameters and electronic polarizability were studied. • Addition of more Se to CdSSe matrix led to improve the opto-electrical properties. • New data were obtained and

  7. Out-of-tank evaporator demonstration: Tanks focus area

    International Nuclear Information System (INIS)

    1998-11-01

    Approximately 100 million gal of liquid waste is stored in underground storage tanks (UST)s at the Hanford Site, Idaho National Engineering and Environmental Laboratory (INEEL), Savannah River Site (SRS), and Oak Ridge Reservation (ORR). This waste is radioactive with a high salt content. The US Department of Energy (DOE) wants to minimize the volume of radioactive liquid waste in USTs by removing the excess water. This procedure conserves tank space; lowers the cost of storage; and reduces the volume of wastes subsequently requiring separation, immobilization, and disposal. The Out-of-Tank Evaporator Demonstration (OTED) was initiated to test a modular, skid-mounted evaporator. A mobile evaporator system manufactured by Delta Thermal Inc. was selected. The evaporator design was routinely used in commercial applications such as concentrating metal-plating wastes for recycle and concentrating ethylene glycol solutions. In FY 1995, the skid-mounted evaporator system was procured and installed in an existing ORNL facility (Building 7877) with temporary shielding and remote controls. The evaporator system was operational in January 1996. The system operated 24 h/day and processed 22,000 gal of Melton Valley Storage Tank (MVST) supernatant. The distillate contained essentially no salts or radionuclides. Upon completion of the demonstration, the evaporator underwent decontamination testing to illustrate the feasibility of hands-on maintenance and potential transport to another DOE facility. This report describes the process and the evaporator, its performance at ORNL, future plans, applications of this technology, cost estimates, regulatory and policy considerations, and lessons learned

  8. Evaporation Kinetics of Polyol Droplets: Determination of Evaporation Coefficients and Diffusion Constants

    Science.gov (United States)

    Su, Yong-Yang; Marsh, Aleksandra; Haddrell, Allen E.; Li, Zhi-Ming; Reid, Jonathan P.

    2017-11-01

    In order to quantify the kinetics of mass transfer between the gas and condensed phases in aerosol, physicochemical properties of the gas and condensed phases and kinetic parameters (mass/thermal accommodation coefficients) are crucial for estimating mass fluxes over a wide size range from the free molecule to continuum regimes. In this study, we report measurements of the evaporation kinetics of droplets of 1-butanol, ethylene glycol (EG), diethylene glycol (DEG), and glycerol under well-controlled conditions (gas flow rates and temperature) using the previously developed cylindrical electrode electrodynamic balance technique. Measurements are compared with a model that captures the heat and mass transfer occurring at the evaporating droplet surface. The aim of these measurements is to clarify the discrepancy in the reported values of mass accommodation coefficient (αM, equals to evaporation coefficient based on microscopic reversibility) for 1-butanol, EG, and DEG and improve the accuracy of the value of the diffusion coefficient for glycerol in gaseous nitrogen. The uncertainties in the thermophysical and experimental parameters are carefully assessed, the literature values of the vapor pressures of these components are evaluated, and the plausible ranges of the evaporation coefficients for 1-butanol, EG, and DEG as well as uncertainty in diffusion coefficient for glycerol are reported. Results show that αM should be greater than 0.4, 0.2, and 0.4 for EG, DEG, and 1-butanol, respectively. The refined values are helpful for accurate prediction of the evaporation/condensation rates.

  9. Two phases of droplet evaporation during plasma arc spraying: reply to Chen's comment about the 'rocket' effect under conditions of thermal plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Nemchinsky, V A [Key College, 225 Dania Beach Blvd, Dania Beach, FL 33040 (United States)

    2007-07-07

    The heating history of a droplet during its flight can be divided into two phases: (a) the initial phase when evaporation, although it occurs, does not change the heat balance of the droplet much (the case considered in our previous paper and (b) the final phase when the cooling due to evaporation balances the heat flux from the plasma. The later phase is considered in Chen's comment. In our reply, a very straightforward consideration demonstrates that even in the final phase of the droplet flight, the 'rocket' effect can be significant. (reply)

  10. Miniature electron bombardment evaporation source: evaporation rate measurement

    International Nuclear Information System (INIS)

    Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

    1997-01-01

    Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

  11. Evaporation and Antievaporation Instabilities

    Directory of Open Access Journals (Sweden)

    Andrea Addazi

    2017-10-01

    Full Text Available We review (antievaporation phenomena within the context of quantum gravity and extended theories of gravity. The (antievaporation effect is an instability of the black hole horizon discovered in many different scenarios: quantum dilaton-gravity, f ( R -gravity, f ( T -gravity, string-inspired black holes, and brane-world cosmology. Evaporating and antievaporating black holes seem to have completely different thermodynamical features compared to standard semiclassical black holes. The purpose of this review is to provide an introduction to conceptual and technical aspects of (antievaporation effects, while discussing problems that are still open.

  12. Evaporation of inclined water droplets

    Science.gov (United States)

    Kim, Jin Young; Hwang, In Gyu; Weon, Byung Mook

    2017-01-01

    When a drop is placed on a flat substrate tilted at an inclined angle, it can be deformed by gravity and its initial contact angle divides into front and rear contact angles by inclination. Here we study on evaporation dynamics of a pure water droplet on a flat solid substrate by controlling substrate inclination and measuring mass and volume changes of an evaporating droplet with time. We find that complete evaporation time of an inclined droplet becomes longer as gravitational influence by inclination becomes stronger. The gravity itself does not change the evaporation dynamics directly, whereas the gravity-induced droplet deformation increases the difference between front and rear angles, which quickens the onset of depinning and consequently reduces the contact radius. This result makes the evaporation rate of an inclined droplet to be slow. This finding would be important to improve understanding on evaporation dynamics of inclined droplets. PMID:28205642

  13. 242-A evaporator hazards assessment

    International Nuclear Information System (INIS)

    Johnson, T.L.

    1998-01-01

    This document establishes the technical basis in support of Emergency Planning activities for the 242-A Evaporator, on the Hanford Site. Through this document the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated. The evaporator sues a conventional, forced-circulation, vacuum evaporation system to concentrate radioactive waste solutions. This concentration results in the reduction in waste volume and reduces the number of double-shelled tanks required to store the waste

  14. Energy consumption during Refractance Window evaporation of selected berry juices

    Energy Technology Data Exchange (ETDEWEB)

    Nindo, C.I.; Tang, J. [Washington State University, Pullman, WA (United States). Dept. of Biological Systems Engineering; Powers, J.R. [Washington State University, Pullman, WA (United States). Dept. of Food Science and Human Nutrition; Bolland, K. [MCD Technologies, Tacoma, WA (United States)

    2004-07-01

    The Refractance Window evaporator represents a novel concept in the design of evaporation systems for small food processing plants. In this system thermal energy from circulating hot water is transmitted through a plastic sheet to evaporate water from a liquid product flowing concurrently on the top surface of the plastic. The objectives of this study were to investigate the heat transfer characteristics of this evaporator, determine its energy consumption, and capacity at different tilt angles and product flow rates. The system performance was evaluated with tap water, raspberry juice, and blueberry juice and puree as feed. With a direct steam injection heating method, the steam economy ranged from 0.64 to 0.84, while the overall heat transfer coefficient (U) was 666 W m{sup -2} {sup o}C{sup -1}. Under this condition, the highest evaporation capacity was 27.1 kg h{sup -1} m{sup -2} for blueberry juice and 31.8 kg h{sup -1} m{sup -2} for blueberry puree. The energy consumption was 2492-2719 kJ kg{sup -1} of water evaporated. Installation of a shell and tube heat exchanger with better temperature control minimized incidences of boiling and frequent discharge of condensate. The steam economy, highest evaporation rate and overall heat transfer coefficient increased to 0.99, 36.0 kg h{sup -1} m{sup -2} and 733 W m{sup -2} {sup o}C{sup -1}, respectively. [Author].

  15. Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure

    Science.gov (United States)

    Canpolat, Nurtac

    2006-01-01

    This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

  16. HYBRID SELECTIVE NON-CATALYTIC REDUCTION (SNCR)/SELECTIVE CATALYTIC REDUCTION (SCR) DEMONSTRATION FOR THE REMOVAL OF NOx FROM BOILER FLUE GASES; FINAL

    International Nuclear Information System (INIS)

    Jerry B. Urbas

    1999-01-01

    The U. S. Department of Energy (DOE), Electric Power Research Institute (EPRI), Pennsylvania Electric Energy Research Council, (PEERC), New York State Electric and Gas and GPU Generation, Inc. jointly funded a demonstration to determine the capabilities for Hybrid SNCR/SCR (Selective Non-Catalytic Reduction/Selective Catalytic Reduction) technology. The demonstration site was GPU Generation's Seward Unit No.5 (147MW) located in Seward Pennsylvania. The demonstration began in October of 1997 and ended in December 1998. DOE funding was provided through Grant No. DE-FG22-96PC96256 with T. J. Feeley as the Project Manager. EPRI funding was provided through agreements TC4599-001-26999 and TC4599-002-26999 with E. Hughes as the Project Manager. This project demonstrated the operation of the Hybrid SNCR/SCR NO(sub x) control process on a full-scale coal fired utility boiler. The hybrid technology was expected to provide a cost-effective method of reducing NO(sub x) while balancing capital and operation costs. An existing urea based SNCR system was modified with an expanded-duct catalyst to provide increased NO(sub x) reduction efficiency from the SNCR while producing increased ammonia slip levels to the catalyst. The catalyst was sized to reduce the ammonia slip to the air heaters to less than 2 ppm while providing equivalent NO(sub x) reductions. The project goals were to demonstrate hybrid technology is capable of achieving at least a 55% reduction in NO(sub x) emissions while maintaining less than 2ppm ammonia slip to the air heaters, maintain flyash marketability, verify the cost benefit and applicability of Hybrid post combustion technology, and reduce forced outages due to ammonium bisulfate (ABS) fouling of the air heaters. Early system limitations, due to gas temperature stratification, restricted the Hybrid NO(sub x) reduction capabilities to 48% with an ammonia slip of 6.1 mg/Nm(sup 3) (8 ppm) at the catalyst inlet. After resolving the stratification problem

  17. HYBRID SELECTIVE NON-CATALYTIC REDUCTION (SNCR)/SELECTIVE CATALYTIC REDUCTION (SCR) DEMONSTRATION FOR THE REMOVAL OF NOx FROM BOILER FLUE GASES

    Energy Technology Data Exchange (ETDEWEB)

    Jerry B. Urbas

    1999-05-01

    The U. S. Department of Energy (DOE), Electric Power Research Institute (EPRI), Pennsylvania Electric Energy Research Council, (PEERC), New York State Electric and Gas and GPU Generation, Inc. jointly funded a demonstration to determine the capabilities for Hybrid SNCR/SCR (Selective Non-Catalytic Reduction/Selective Catalytic Reduction) technology. The demonstration site was GPU Generation's Seward Unit No.5 (147MW) located in Seward Pennsylvania. The demonstration began in October of 1997 and ended in December 1998. DOE funding was provided through Grant No. DE-FG22-96PC96256 with T. J. Feeley as the Project Manager. EPRI funding was provided through agreements TC4599-001-26999 and TC4599-002-26999 with E. Hughes as the Project Manager. This project demonstrated the operation of the Hybrid SNCR/SCR NO{sub x} control process on a full-scale coal fired utility boiler. The hybrid technology was expected to provide a cost-effective method of reducing NO{sub x} while balancing capital and operation costs. An existing urea based SNCR system was modified with an expanded-duct catalyst to provide increased NO{sub x} reduction efficiency from the SNCR while producing increased ammonia slip levels to the catalyst. The catalyst was sized to reduce the ammonia slip to the air heaters to less than 2 ppm while providing equivalent NO{sub x} reductions. The project goals were to demonstrate hybrid technology is capable of achieving at least a 55% reduction in NO{sub x} emissions while maintaining less than 2ppm ammonia slip to the air heaters, maintain flyash marketability, verify the cost benefit and applicability of Hybrid post combustion technology, and reduce forced outages due to ammonium bisulfate (ABS) fouling of the air heaters. Early system limitations, due to gas temperature stratification, restricted the Hybrid NO{sub x} reduction capabilities to 48% with an ammonia slip of 6.1 mg/Nm{sup 3} (8 ppm) at the catalyst inlet. After resolving the stratification

  18. Diffusion and evaporation of a liquid droplet

    Science.gov (United States)

    Shukla, K. N.

    1980-06-01

    The process of evaporation and diffusion of a spherical liquid droplet in an atmosphere of noncondensable gas is studied theoretically. An equation for the shrinkage of the radius of the droplet is derived on the basis of continuity and momentum equations. Further, a conjugate problem consisting of the energy and mass balance for the gaseous environment is formulated. An approximation of thin thermal and diffusion boundary-layers is introduced to simplify the analysis. Results are presented for methanol-nitrogen, ammonia-nitrogen, and sodium-argon systems. It has been observed that the droplet of highly viscous fluid exhibits rapid contraction.

  19. Self-excited hydrothermal waves in evaporating sessile drops

    Science.gov (United States)

    Sefiane, K.; Moffat, J. R.; Matar, O. K.; Craster, R. V.

    2008-08-01

    Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC-72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrothermal waves have been observed in the absence of evaporation in shallow liquid layers subjected to an imposed temperature gradient. In contrast, here both the temperature gradients and the drop thickness vary spatially and temporally and are a natural consequence of the evaporation process.

  20. Evaporative cooling: Effective latent heat of evaporation in relation to evaporation distance from the skin

    NARCIS (Netherlands)

    Havenith, G.; Bröde, P.; Hartog, E.A. den; Kuklane, K.; Holmer, I.; Rossi, R.M.; Richards, M.; Farnworth, B.; Wang, X.

    2013-01-01

    Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has

  1. Self-excited hydrothermal waves in evaporating sessile drops

    OpenAIRE

    Sefiane K.; Moffat J.R.; Matar O.K.; Craster R.V.

    2008-01-01

    Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC- 72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrotherma...

  2. Rapid Evaporation of microbubbles

    Science.gov (United States)

    Gautam, Jitendra; Esmaeeli, Asghar

    2008-11-01

    When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

  3. Advanced multi-evaporator loop thermosyphon

    International Nuclear Information System (INIS)

    Mameli, M.; Mangini, D.; Vanoli, G.F.T.; Araneo, L.; Filippeschi, S.; Marengo, M.

    2016-01-01

    A novel prototype of multi-evaporator closed loop thermosyphon is designed and tested at different heaters position, inclinations and heat input levels, in order to prove that a peculiar arrangement of multiple heaters may be used in order to enhance the flow motion and consequently the thermal performance. The device consists in an aluminum tube (Inner/Outer tube diameter 3.0 mm/5.0 mm), bent into a planar serpentine with five U-turns and partially filled with FC-72, 50% vol. The evaporator zone is equipped with five heated patches (one for each U-turn) in series with respect to the flow path. In the first arrangement, heaters are wrapped on each bend symmetrically, while in the second layout heaters are located on the branch just above the U-turn, non-symmetrical with respect to the gravity direction, in order to promote the fluid circulation in a preferential direction. The condenser zone is cooled by forced air and equipped with a 50 mm transparent section for the flow pattern visualization. The non-symmetrical heater arrangement effectively promotes a stable fluid circulation and a reliable operation for a wider range of heat input levels and orientations with respect to the symmetrical case. In vertical position, the heat flux dissipation exceeds the pool boiling heat transfer limit for FC-72 by 75% and the tube wall temperatures in the evaporator zone are kept lower than 80 °C. Furthermore, the heat flux capability is up to five times larger with respect to the other existing wickless heat pipe technologies demonstrating the attractiveness of the new concept for electronic cooling thermal management. - Highlights: • A novel passive heat transfer device named Multi-Evaporator Loop Thermosyphon is tested. • The loop is investigated at different heating patterns, inclinations and heat power levels. • The non-symmetrical heating configuration promotes the fluid circulation within the loop. • The performance in terms of maximum heat flux exceeds the

  4. Influence of surface wettability on transport mechanisms governing water droplet evaporation.

    Science.gov (United States)

    Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

    2014-08-19

    Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ≲ 60°), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ≲ CA ≲ 90°), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ≳ 90°), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ≥ 90°) when evaporative cooling is strong and the

  5. Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Bue, Grant C.; Stephan, Ryan; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2012-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  6. Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2013-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  7. Hydrothermal waves in evaporating sessile drops

    OpenAIRE

    Brutin, D.; Rigollet, F.; Niliot, C. Le

    2009-01-01

    Drop evaporation is a simple phenomena but still unclear concerning the mechanisms of evaporation. A common agreement of the scientific community based on experimental and numerical work evidences that most of the evaporation occurs at the triple line. However, the rate of evaporation is still empirically predicted due to the lack of knowledge on the convection cells which develop inside the drop under evaporation. The evaporation of sessile drop is more complicated than it appears due to the...

  8. Control of black hole evaporation?

    International Nuclear Information System (INIS)

    Ahn, Doyeol

    2007-01-01

    Contradiction between Hawking's semi-classical arguments and the string theory on the evaporation of a black hole has been one of the most intriguing problems in fundamental physics. A final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that the original Hawking effect can also be regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of the Hawking boundary condition may affect the information transfer from the initial collapsing matter to the outgoing Hawking radiation during the evaporation process and as a result the evaporation process itself, significantly

  9. Evaporation and condensation heat transfer with a noncondensable gas present

    International Nuclear Information System (INIS)

    Murase, M.; Kataoka, Y.; Fujii, T.

    1993-01-01

    To evaluate the system pressure of an external water wall type containment vessel, which is one of the passive systems for containment cooling, the evaporation and condensation behavior under a noncondensable gas presence has been experimentally examined. In the system, steam evaporated from the suppression pool surface into the wetwell, filled with noncondensable gas, and condensed on the containment vessel wall. The system pressure was the sum of the noncondensable gas pressure and saturated steam pressure in the wetwell. The wetwell temperature was, however, lower than the suppression pool temperature and depended on the thermal resistance on the suppression pool surface. The evaporation and condensation heat transfer coefficients in the presence of air as noncondensable gas were measured and expressed by functions of steam/air mass ratio. The evaporation heat transfer coefficients were one order higher than the condensation heat transfer coefficients because the local noncondensable gas pressure was much lower on the evaporating pool surface than on the condensing liquid surface. Using logal properties of the heat transfer surfaces, there was a similar trend between evaporation and condensation even with a noncondensable gas present. (orig.)

  10. Introducing ultrasonic falling film evaporator for moderate temperature evaporation enhancement.

    Science.gov (United States)

    Dehbani, Maryam; Rahimi, Masoud

    2018-04-01

    In the present study, Ultrasonic Falling Film (USFF), as a novel technique has been proposed to increase the evaporation rate of moderate temperature liquid film. It is a proper method for some applications which cannot be performed at high temperature, such as foodstuff industry, due to their sensitivity to high temperatures. Evaporation rate of sodium chloride solution from an USFF on an inclined flat plate compared to that for Falling Film without ultrasonic irradiation (FF) at various temperatures was investigated. The results revealed that produced cavitation bubbles have different effects on evaporation rate at different temperatures. At lower temperatures, size fluctuation and collapse of bubbles and in consequence induced physical effects of cavitation bubbles resulted in more turbulency and evaporation rate enhancement. At higher temperatures, the behavior was different. Numerous created bubbles joined together and cover the plate surface, so not only decreased the ultrasound vibrations but also reduced the evaporation rate in comparison with FF. The highest evaporation rate enhancement of 353% was obtained at 40 °C at the lowest Reynolds number of 250. In addition, the results reveal that at temperature of 40 °C, USFF has the highest efficiency compared to FF. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Evaporative cycles - in theory and in practise

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, P.M.

    2000-08-01

    The thesis is based on applied research, rather closed to industrial development. The developed simulation model, for pre-design of evaporative gas turbine cycles, has been validated in a 600 kW pilot plant and in rebuilt turbo-charged diesel engines. Besides of the work with the thesis including theoretical modelling and hardware development concerning wet cycles, the work has also resulted in three patents dealing with the technique studied. The main feature of the evaporative cycles is the way the integration between the gas and liquid flows is executed, combined with using low-level heat gathered into the liquid phase which is later used to evaporate the liquid itself in a humidification tower. In this tower, the mass- and heat transfer take place under stable physical laws, and if the tower is properly designed, the distilling effect in the tower will also be high. Today the combined cycle has the best thermal efficiency to generate electricity from fuels. Every new power cycle, including the evaporative cycles, will therefore be compared with power stations based on combined cycles. In evaporative cycles, the steam bottoming cycle of the combined cycles has been eliminated. Instead the 'steam' cycle is integrated into the gas cycle. This action has a favourable effect on thermal efficiency and on NO{sub x} formation in the combustion zone. The major part of this thesis is about the EvGT-project. At Lund University, the major objective of this project was to develop, design, erect and operate the world's first evaporative gas turbine unit. The objective was accomplished in 1999, and in the process of reaching the objective, rather large modelling errors, both thermodynamic and dimensioning of the humidification tower, have been detected in the open literature. It seems as if the pressure dependency of the humidification process has been underestimated in the models used today. The EvGT-pilot plant at Lund University was built and taken into

  12. Dual manifold heat pipe evaporator

    Science.gov (United States)

    Adkins, D.R.; Rawlinson, K.S.

    1994-01-04

    An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

  13. The evaporative vector: Homogeneous systems

    International Nuclear Information System (INIS)

    Klots, C.E.

    1987-05-01

    Molecular beams of van der Waals molecules are the subject of much current research. Among the methods used to form these beams, three-sputtering, laser ablation, and the sonic nozzle expansion of neat gases - yield what are now recognized to be ''warm clusters.'' They contain enough internal energy to undergo a number of first-order processes, in particular that of evaporation. Because of this evaporation and its attendant cooling, the properties of such clusters are time-dependent. The states of matter which can be arrived at via an evaporative vector on a typical laboratory time-scale are discussed. Topics include the (1) temperatures, (2) metastability, (3) phase transitions, (4) kinetic energies of fragmentation, and (5) the expression of magical properties, all for evaporating homogeneous clusters

  14. Operational characteristics of miniature loop heat pipe with flat evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Gai, Dongxing; Liu, Zhichun; Liu, Wei; Yang, Jinguo [Huazhong University of Science and Technology, School of Energy and Power Engineering, Wuhan, Hubei (China)

    2009-12-15

    Loop heat pipes are heat transfer devices whose operating principle is based on the evaporation and condensation of a working fluid, and which use the capillary pumping forces to ensure the fluid circulation. A series of tests have been carried out with a miniature loop heat pipe (mLHP) with flat evaporator and fin-and-tube type condenser. The loop is made of pure copper with stainless mesh wick and methanol as the working fluid. Detailed study is conducted on the start-up reliability of the mLHP at high as well as low heat loads. During the testing of mLHP under step power cycles, the thermal response presented by the loop to achieve steady state is very short. At low heat loads, temperature oscillations are observed throughout the loop. The amplitudes and frequencies of these fluctuations are large at evaporator wall and evaporator inlet. It is expected that the extent and nature of the oscillations occurrence is dependent on the thermal and hydrodynamic conditions inside the compensation chamber. The thermal resistance of the mLHP lies between 0.29 and 3.2 C/W. The effects of different liquid charging ratios and the tilt angles to the start-up and the temperature oscillation are studied in detail. (orig.)

  15. Fuel Evaporation in an Atmospheric Premixed Burner: Sensitivity Analysis and Spray Vaporization

    Directory of Open Access Journals (Sweden)

    Dávid Csemány

    2017-12-01

    Full Text Available Calculation of evaporation requires accurate thermophysical properties of the liquid. Such data are well-known for conventional fossil fuels. In contrast, e.g., thermal conductivity or dynamic viscosity of the fuel vapor are rarely available for modern liquid fuels. To overcome this problem, molecular models can be used. Currently, the measurement-based properties of n-heptane and diesel oil are compared with estimated values, using the state-of-the-art molecular models to derive the temperature-dependent material properties. Then their effect on droplet evaporation was evaluated. The critical parameters were liquid density, latent heat of vaporization, boiling temperature, and vapor thermal conductivity where the estimation affected the evaporation time notably. Besides a general sensitivity analysis, evaporation modeling in a practical burner ended up with similar results. By calculating droplet motion, the evaporation number, the evaporation-to-residence time ratio can be derived. An empirical cumulative distribution function is used for the spray of the analyzed burner to evaluate evaporation in the mixing tube. Evaporation number did not exceed 0.4, meaning a full evaporation prior to reaching the burner lip in all cases. As droplet inertia depends upon its size, the residence time has a minimum value due to the phenomenon of overshooting.

  16. DWPF Recycle Evaporator Simulant Tests

    International Nuclear Information System (INIS)

    Stone, M

    2005-01-01

    Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming, scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to

  17. Evaporative water loss, relative water economy and evaporative partitioning of a heterothermic marsupial, the monito del monte (Dromiciops gliroides).

    Science.gov (United States)

    Withers, Philip C; Cooper, Christine E; Nespolo, Roberto F

    2012-08-15

    We examine here evaporative water loss, economy and partitioning at ambient temperatures from 14 to 33°C for the monito del monte (Dromiciops gliroides), a microbiotheriid marsupial found only in temperate rainforests of Chile. The monito's standard evaporative water loss (2.58 mg g(-1) h(-1) at 30°C) was typical for a marsupial of its body mass and phylogenetic position. Evaporative water loss was independent of air temperature below thermoneutrality, but enhanced evaporative water loss and hyperthermia were the primary thermal responses above the thermoneutral zone. Non-invasive partitioning of total evaporative water loss indicated that respiratory loss accounted for 59-77% of the total, with no change in respiratory loss with ambient temperature, but a small change in cutaneous loss below thermoneutrality and an increase in cutaneous loss in and above thermoneutrality. Relative water economy (metabolic water production/evaporative water loss) increased at low ambient temperatures, with a point of relative water economy of 15.4°C. Thermolability had little effect on relative water economy, but conferred substantial energy savings at low ambient temperatures. Torpor reduced total evaporative water loss to as little as 21% of normothermic values, but relative water economy during torpor was poor even at low ambient temperatures because of the relatively greater reduction in metabolic water production than in evaporative water loss. The poor water economy of the monito during torpor suggests that negative water balance may explain why hibernators periodically arouse to normothermia, to obtain water by drinking or via an improved water economy.

  18. Localised boundary air layer and clothing evaporative resistances for individual body segments.

    Science.gov (United States)

    Wang, Faming; del Ferraro, Simona; Lin, Li-Yen; Sotto Mayor, Tiago; Molinaro, Vincenzo; Ribeiro, Miguel; Gao, Chuansi; Kuklane, Kalev; Holmér, Ingvar

    2012-01-01

    Evaporative resistance is an important parameter to characterise clothing thermal comfort. However, previous work has focused mainly on either total static or dynamic evaporative resistance. There is a lack of investigation of localised clothing evaporative resistance. The objective of this study was to study localised evaporative resistance using sweating thermal manikins. The individual and interaction effects of air and body movements on localised resultant evaporative resistance were examined in a strict protocol. The boundary air layer's localised evaporative resistance was investigated on nude sweating manikins at three different air velocity levels (0.18, 0.48 and 0.78 m/s) and three different walking speeds (0, 0.96 and 1.17 m/s). Similarly, localised clothing evaporative resistance was measured on sweating manikins at three different air velocities (0.13, 0.48 and 0.70 m/s) and three walking speeds (0, 0.96 and 1.17 m/s). Results showed that the wind speed has distinct effects on local body segments. In contrast, walking speed brought much more effect on the limbs, such as thigh and forearm, than on body torso, such as back and waist. In addition, the combined effect of body and air movement on localised evaporative resistance demonstrated that the walking effect has more influence on the extremities than on the torso. Therefore, localised evaporative resistance values should be provided when reporting test results in order to clearly describe clothing local moisture transfer characteristics. Localised boundary air layer and clothing evaporative resistances are essential data for clothing design and assessment of thermal comfort. A comprehensive understanding of the effects of air and body movement on localised evaporative resistance is also necessary by both textile and apparel researchers and industry.

  19. Evaluation of the correlations for predicting evaporative loss from water body

    International Nuclear Information System (INIS)

    Yilmaz, T.P.; Aybar, H.S.

    1999-01-01

    Water evaporation (evaporation from here on) is a natural phenomenon that is important for system design and system safety in many engineering branches. Indeed, evaporative heat and mass loss are observed and calculated in very diverse situations, such as irrigation plants, water purification plants, cooling ponds, lakes, dams, swimming pools, health spas, management of liquid wastes as in evaporation pools, and spent fuel pools in nuclear power plants. There are a number of correlations obtained from experimental studies that predict the evaporative heat and mass loss from a water body. This study aims to summarize and to compare the existing evaporation correlations to determine the upper and lower bounding correlations for use in various thermal-hydraulic analyses of systems. Currently and widely used, six correlations found in the literature have been selected and tested using the major parameters of evaporation such as water temperature, air relative humidity, air velocity, and temperature. The comparison test cases show that ASHRAE (1991) and Ryan et al. (1974) equations result in the highest evaporative loss, while the Brady et al. (1969) equation provides the lowest evaporative loss in most conditions. Engineering designers may sometimes need the upper bound value of evaporative loss or sometimes the lower bound value for a conservative calculation. The authors conclude that using a single equation does not provide the conservative calculation for every situation and show which correlation gives the lower or upper bound for different conditions

  20. Capillary condenser/evaporator

    Science.gov (United States)

    Valenzuela, Javier A. (Inventor)

    2010-01-01

    A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

  1. Power balance equation in electron beam evaporation process

    International Nuclear Information System (INIS)

    Blumenfeld, L.; Soubbaramayer.

    1994-01-01

    The aim of the paper is to solve the equation giving the total power of the gun, used in the electron beam evaporation process, in terms of the power used to generated the vapor stream and the three main power losses due to three parasite phenomena: turbulent thermal convection in the molten pool, electron back scattering and heat radiation from the vapor emitting surface. Scaling laws are first reviewed and results are given with the example of the evaporation of aluminium with a 5 kW axisymmetric gun working in steady state mode. The influence of an applied magnetic field on the evaporation rate is also examined. 5 refs., 3 figs., 1 tab

  2. Hollow-Fiber Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

    2013-01-01

    The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.

  3. Technologies of Selective Energy Supply at Evaporation of Food Solutes

    Directory of Open Access Journals (Sweden)

    Burdo O.G.

    2017-04-01

    Full Text Available The aim of the research is to create innovative evaporating equipment that can produce concentrates with a high content of solids, with a low level of thermal effects on raw materials. The significance of the solution of technological problems of the key process of food technologies - concentration of liquid solutions (juices, extracts, etc. is shown. Problems and scientific contradictions are formulated and the hypothesis on using of electromagnetic energy sources for direct energy transfer to solution’s moisture has been offered. The prospects of such an energy effect are proved by the energy management methods. The schemes of fuel energy conversion for the conventional thermal concentration technology and the innovative plant based on the electromagnetic energy generators are presented. By means of the similarity theory the obtained model is transformed to the criterial one depicted kinetic of evaporation process at the electromagnetic field action. The dimensionless capacity of the plant is expressed by the dependence between the Energetic effect number and relative moisture content. The scheme of automated experimental system for study of the evaporation process in the microwave field is shown. The experimental results of juice evaporation are presented. It has been demonstrated that the technologies of selective energy supply represent an effective tool for improvement of juice concentration evaporative plants. The main result of the research is design of the evaporator that allows reaching juice concentrates with °brix 95 at the temperature as low as 35 °С, i.e. 2…3 times superior than traditional technologies.

  4. Development of a model for spray evaporation based on droplet analysis

    KAUST Repository

    Chen, Q.; Thu, K.; Bui, T.D.; Li, Y.; Ng, Kim Choon; Chua, K.J.

    2016-01-01

    Extreme flash evaporation occurs when superheated liquid is sprayed into a low pressure zone. This method has high potential to improve the performance of thermally-driven desalination plants. To enable a more in-depth understanding on flash evaporation of a superheated feed water spray, a theoretical model has been developed with key considerations given to droplet motion and droplet size distribution. The model has been validated against 14 experimental data sets from literature sources to within 12% discrepancy. This model is capable of accurately predicting the water productivity and thermal efficiency of existing spray evaporator under specific operating conditions. Employing this model, the effect of several design parameters on system performance was investigated. Key results revealed that smaller droplet enabled faster evaporation process while higher initial droplet velocity promoted water productivity. Thermal utilization marginally changes with the degree of superheat, which renders a quick design calculation of the brine temperature without the need for iterations. © 2016 Elsevier B.V.

  5. Development of a model for spray evaporation based on droplet analysis

    KAUST Repository

    Chen, Q.

    2016-08-20

    Extreme flash evaporation occurs when superheated liquid is sprayed into a low pressure zone. This method has high potential to improve the performance of thermally-driven desalination plants. To enable a more in-depth understanding on flash evaporation of a superheated feed water spray, a theoretical model has been developed with key considerations given to droplet motion and droplet size distribution. The model has been validated against 14 experimental data sets from literature sources to within 12% discrepancy. This model is capable of accurately predicting the water productivity and thermal efficiency of existing spray evaporator under specific operating conditions. Employing this model, the effect of several design parameters on system performance was investigated. Key results revealed that smaller droplet enabled faster evaporation process while higher initial droplet velocity promoted water productivity. Thermal utilization marginally changes with the degree of superheat, which renders a quick design calculation of the brine temperature without the need for iterations. © 2016 Elsevier B.V.

  6. Bypass line assisted start-up of a loop heat pipe with a flat evaporator

    International Nuclear Information System (INIS)

    Boo, Joon Hong; Jung, Eui Guk

    2009-01-01

    Loop heat pipes often experience start-up problems especially under low thermal loads. A bypass line was installed between the evaporator and the liquid reservoir to alleviate the difficulties associated with start-up of a loop heat pipe with flat evaporator. The evaporator and condenser had dimensions of 40 mm (W) by 50 mm (L). The wall and tube materials were stainless steel and the working fluid was methanol. Axial grooves were provided in the flat evaporator to serve as vapor passages. The inner diameters of liquid and vapor transport lines were 2 mm and 4 mm, respectively, and the length of the two lines was 0.5 m each. The thermal load range was up to 130 W for horizontal alignment with the condenser temperature of 10 .deg. C. The experimental results showed that the minimum thermal load for start-up was lowered by 37% when the bypass line was employed

  7. Water-evaporation-induced electricity with nanostructured carbon materials.

    Science.gov (United States)

    Xue, Guobin; Xu, Ying; Ding, Tianpeng; Li, Jia; Yin, Jun; Fei, Wenwen; Cao, Yuanzhi; Yu, Jin; Yuan, Longyan; Gong, Li; Chen, Jian; Deng, Shaozhi; Zhou, Jun; Guo, Wanlin

    2017-05-01

    Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

  8. Influence of electron evaporative cooling on ultracold plasma expansion

    International Nuclear Information System (INIS)

    Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob

    2013-01-01

    The expansion of ultracold neutral plasmas (UCP) is driven primarily by the thermal pressure of the electron component and is therefore sensitive to the electron temperature. For typical UCP spatial extents, evaporative cooling has a significant influence on the UCP expansion rate at lower densities (less than 10 8 /cm 3 ). We studied the effect of electron evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in electron temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold plasma densities, sizes, and electron temperatures to determine over what parameter range electron evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and electrons in the ultracold plasma

  9. Refractory material crucibles evaluation for U evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Damiao, A.J.; Vasconcelos, G.; Silveira, C.A.B.; Rodrigues, N.A.S. [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados

    1996-12-31

    In studies that involve small amounts of U vapor generation, such as spectroscopy or thin films, most of the E-gun power is delivered to the cooling system. Normally crucibles are used as container and thermal insulator. Since liquid U is extremely reactive at evaporation temperatures, the crucibles are seriously attacked, decreasing the insulation efficiency and adding contaminants to the U vapor. There is no complete solution for the problem, however, with a careful choice of materials, one can design crucibles with extended lifetime and reduced contamination. This work reports some preliminary results we have obtained in the assessing of crucible materials and design, such as, graphite, Si C, vitreous carbon and Al{sub 2} O{sub 3}. (author) 1 refs., 3 figs.,2 tabs.

  10. Refractory material crucibles evaluation for U evaporation

    International Nuclear Information System (INIS)

    Damiao, A.J.; Vasconcelos, G.; Silveira, C.A.B.; Rodrigues, N.A.S.

    1996-01-01

    In studies that involve small amounts of U vapor generation, such as spectroscopy or thin films, most of the E-gun power is delivered to the cooling system. Normally crucibles are used as container and thermal insulator. Since liquid U is extremely reactive at evaporation temperatures, the crucibles are seriously attacked, decreasing the insulation efficiency and adding contaminants to the U vapor. There is no complete solution for the problem, however, with a careful choice of materials, one can design crucibles with extended lifetime and reduced contamination. This work reports some preliminary results we have obtained in the assessing of crucible materials and design, such as, graphite, Si C, vitreous carbon and Al 2 O 3 . (author)

  11. Surface wettability and triple line behavior controlled by nano-coatings: effects on the sessile drop evaporation

    Science.gov (United States)

    Sobac, Benjamin; Brutin, David; Gavillet, Jerôme

    2010-11-01

    Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop posed on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (SiOx, SiOc and CF), the wettability and the triple line dynamic of a sessile drop under natural phase change. The experiment consists in analyzing simultaneously the kinetics of evaporation, internal thermal motion and heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamic of the evaporative heat flux appears clearly different for a drop evaporating in pinned mode than in receding mode. Moreover, the kinetics of evaporation, the internal flow structure and the evaporative heat flux are drastically influenced by the wettability the substrate.

  12. Evaporative cooling in ATLAS – present and future

    CERN Document Server

    Viehhauser, G; The ATLAS collaboration

    2010-01-01

    Evaporative cooling is gaining interest in the particle physics community, due to the promise of reduced material, good temperature uniformity, and the wide range of temperatures accessible. The largest such system to-date operates in ATLAS, where it removes the heat from the semiconductor detector systems (Silicon strips and pixels). During the installation and commissioning of this system many lessons had to be learned. In parallel we have re-evaluated the requirements for the cooling system, in particular for the evaporation temperature, over the full ATLAS operational lifetime, and can compare them to the real system performance. The critical requirement is for thermal stability at the end of the operation in the high-radiation environment. To predict this we have developed a simple thermal model of the detector modules which yields analytical expressions to evaluate the results of changes in the operating conditions. After a comparison of the revised requirements and the actual present cooling system per...

  13. The sustainability of LNG evaporation

    NARCIS (Netherlands)

    Stougie, L.; Van der Kooi, H.J.

    2011-01-01

    Numerous LNG (Liquefied Natural Gas) import terminals are under construction to fulfil the growing demand for energy carriers. After storage in tanks, the LNG needs to be heated and evaporated, also called ‘regasified’, to the natural gas needed in households and industry. Several options exist for

  14. Evaporation in relation to hydrology

    NARCIS (Netherlands)

    Wartena, L.; Keijman, J.Q.; Bruijn, H.A.R. de; Bakel, P.J.T. van; Stricker, J.N.M.; Velds, C.A.

    1981-01-01

    In meteorology some topics enjoy particular interest from other disciplines. The interest of hydrologists for the evaporation of water is a case in point, understandably and rightly so. In fact, over the last few decades, hydrology has clearly done more than using meteorological knowledge thus

  15. Micro-evaporation electrolyte concentrator

    NARCIS (Netherlands)

    Timmer, B.H.; van Delft, K.M.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2003-01-01

    The sensitivity of miniaturized chemical analysis systems depends most of the time on the obtainable detection limit. Concentrating the analyte prior to the detection system can enhance the detection limit. In this writing an analyte concentrator is presented that makes use of evaporation to

  16. Evaporation rate of nucleating clusters.

    Science.gov (United States)

    Zapadinsky, Evgeni

    2011-11-21

    The Becker-Döring kinetic scheme is the most frequently used approach to vapor liquid nucleation. In the present study it has been extended so that master equations for all cluster configurations are included into consideration. In the Becker-Döring kinetic scheme the nucleation rate is calculated through comparison of the balanced steady state and unbalanced steady state solutions of the set of kinetic equations. It is usually assumed that the balanced steady state produces equilibrium cluster distribution, and the evaporation rates are identical in the balanced and unbalanced steady state cases. In the present study we have shown that the evaporation rates are not identical in the equilibrium and unbalanced steady state cases. The evaporation rate depends on the number of clusters at the limit of the cluster definition. We have shown that the ratio of the number of n-clusters at the limit of the cluster definition to the total number of n-clusters is different in equilibrium and unbalanced steady state cases. This causes difference in evaporation rates for these cases and results in a correction factor to the nucleation rate. According to rough estimation it is 10(-1) by the order of magnitude and can be lower if carrier gas effectively equilibrates the clusters. The developed approach allows one to refine the correction factor with Monte Carlo and molecular dynamic simulations.

  17. Structure and thermal stability of arc evaporated (Ti{sub 0.33}Al{sub 0.67}){sub 1-x}Si{sub x}N thin films

    Energy Technology Data Exchange (ETDEWEB)

    Flink, A. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden)], E-mail: axefl@ifm.liu.se; Andersson, J.M. [Seco Tools AB, SE-737 82 Fagersta (Sweden); Alling, B. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden); Institute of Physics of Complex Matter, Swiss Federal Institute of Technology, Lausanne (EPFL) 1015 Lausanne (Switzerland); Daniel, R. [Christian Doppler Laboratory for Advanced Hard Coatings, Department of Physical Metallurgy, University of Leoben, A-8700 Leoben (Austria); Sjoelen, J.; Karlsson, L. [Seco Tools AB, SE-737 82 Fagersta (Sweden); Hultman, L. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden)

    2008-11-28

    (Ti{sub 0.33}Al{sub 0.67}){sub 1-x}Si{sub x}N (0 {<=} x {<=} 0.29) thin solid films were deposited onto cemented carbide substrates by arc evaporation and analyzed using analytical electron microscopy, X-ray diffraction, nanoindentation, and density functional theory. As-deposited films with x {<=} 0.02 consisted mainly of a metastable c-(Ti,Al)N solid solution for which Si serves as a veritable grain refiner. Additional Si promoted growth of a hexagonal wurtzite (Al,Ti,Si)N solid solution, which dominated at 0.02 < x < 0.17. For x {>=} 0.17, the films were X-ray amorphous. Despite these widely different microstructures, all as-deposited films had nanoindentation hardness in the narrow range of 22-25 GPa. Isothermal annealing of the x = 0.01 alloy film at a temperature of 900 deg. C , corresponding to that in turning operation, resulted in spinodal decomposition into c-AlN and TiN and precipitation of h-AlN. For x = 0.09 films, annealing between 600 deg. C and 1000 deg. C yielded c-TiN precipitation from the h-(Al,Ti,Si)N phase. Furthermore, the x = 0.01 and x = 0.09 films exhibited substantial age hardening at 900 deg. C , to 34 GPa and 29 GPa due to spinodal decomposition and c-TiN precipitation, respectively. Films with a majority of c-(Ti,Al)N phase worked best in steel turning tests, while films with x > 0.02 developed cracks during such operation. We propose that the cracks are due to tensile strain which is caused by a decrease in molar volume during the phase transformation from hexagonal wurtzite (Al,Ti,Si)N into cubic TiN phase, which results in degradation in machining performance.

  18. Quantifying Evaporation in a Permeable Pavement System

    Science.gov (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  19. Fundamentals of evaporation and condensation phenomena

    International Nuclear Information System (INIS)

    Munir, Z.A.

    1979-01-01

    Fundamental relationships governing evaporation and condensation processes are reviewed. The terrace-ledge-kink (TLK) model is discussed in terms of atomic steps comprising growth and evaporation of crystals. Recent results in the field are described

  20. The study on the evaporation cooling efficiency and effectiveness of cooling tower of film type

    International Nuclear Information System (INIS)

    Li Yingjian; You Xinkui; Qiu Qi; Li Jiezhi

    2011-01-01

    Based on heat and mass transport mechanism of film type cooling, which was combined with an on-site test on counter flow film type cooling tower, a mathematical model on the evaporation and cooling efficiency and effectiveness has been developed. Under typical climatic conditions, air conditioning load and the operating condition, the mass and heat balances have been calculated for the air and the cooling water including the volume of evaporative cooling water. Changing rule has been measured and calculated between coefficient of performance (COP) and chiller load. The influences of air and cooling water parameters on the evaporative cooling efficiency were analyzed in cooling tower restrained by latent heat evaporative cooling, and detailed derivation and computation revealed that both the evaporative cooling efficiency and effectiveness of cooling tower are the same characteristics parameters of the thermal performance of a cooling tower under identical assumptions.

  1. An experimental study of the surface chemistry and evaporation kinetics of liquid sodium

    International Nuclear Information System (INIS)

    Becker, C.H.

    1983-01-01

    The evaporation rate and internal energy distribution of Na 2 evaporating from clean liquid Na and liquid Na exposed separately to O 2 and benzene were investigated by laser spectroscopy. The evaporating Na 2 was always found to be in thermal equilibrium with the surface. Oxygen increased the evaporation rate while benzene diminished it. A 3 keV Ar + beam was used to examine the surface by monitoring secondary ion emission. Ion emission from clean and oxygen exposed Na was extremely low; only limits could be established. Ion emission from sodium exposed to benzene could be observed only at lowered temperatures. The secondary ion emission, as well as visual observations of Na( 2 P-> 2 S) emission, are found to correspond to the evaporation rate behavior indicating that the Na surface remains very metal rich even while reacting with impinging oxygen at high (10 monolayers/s) rates. (orig.)

  2. Influence of the wall on the droplet evaporation

    Directory of Open Access Journals (Sweden)

    Misyura S. Y.

    2015-01-01

    Full Text Available Evaporative influence of the wall material and its thickness has been investigated in the present study. The wall influence for heat exchangers is particularly important in the boiling transition regime and in the event of the Leidenfrost temperature. The experimental points significantly diverge in the transition area of the boiling crisis. This fact can be explained by a different residence time of droplet on the wall surface. The discrepancy between the experimental data also takes place at the Leidenfrost temperature. The lower the thermal diffusivity of the wall material (high thermal inertia, the more the wall is cooled under a droplet.

  3. Out-of-tank evaporator demonstration. Final report

    International Nuclear Information System (INIS)

    Lucero, A.J.; Jennings, H.L.; VanEssen, D.C.

    1998-02-01

    The project reported here was conducted to demonstrate a skid-mounted, subatmospheric evaporator to concentrate liquid low-level waste (LLLW) stored in underground tanks at Oak Ridge National Laboratory (ORNL). This waste is similar to wastes stored at Hanford and Savannah River. A single-stage subatmospheric evaporator rated to produce 90 gallons of distillate per hour was procured from Delta Thermal, Inc., of Pensacola, Florida, and installed in an existing building. During the 8-day demonstration, 22,000 gal of LLLW was concentrated by 25% with the evaporator system. Decontamination factors achieved averaged 5 x 10 6 (i.e., the distillate contained five million times less Cesium 137 than the feed). Evaporator performance substantially exceeded design requirements and expectations based on bench-scale surrogate test data. Out-of tank evaporator demonstration operations successfully addressed the feasibility of hands-on maintenance. Demonstration activities indicate that: (1) skid-mounted, mobile equipment is a viable alternative for the treatment of ORNL LLLW, and (2) hands-on maintenance and decontamination for movement to another site is achievable. Cost analysis show that 10% of the demonstration costs will be immediately recovered by elimination of solidification and disposal costs. The entire cost of the demonstration can be recovered by processing the inventory of Melton Valley Storage Tank waste and/or sluice water prior to solidifications. An additional savings of approximately $200,000 per year can be obtained by processing newly generated waste through the system. The results indicate that this type of evaporator system should be considered for application across the DOE complex. 25 refs., 11 figs., 2 tabs

  4. Evaporative lithographic patterning of binary colloidal films.

    Science.gov (United States)

    Harris, Daniel J; Conrad, Jacinta C; Lewis, Jennifer A

    2009-12-28

    Evaporative lithography offers a promising new route for patterning a broad array of soft materials. In this approach, a mask is placed above a drying film to create regions of free and hindered evaporation, which drive fluid convection and entrained particles to regions of highest evaporative flux. We show that binary colloidal films exhibit remarkable pattern formation when subjected to a periodic evaporative landscape during drying.

  5. Evaporative cooling in polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Shimotori, S; Sonai, A [Toshiba Corp. Tokyo (Japan)

    1996-06-05

    The concept of the evaporative cooling for the internally humidified PEFC was confirmed by the experiment. The evaporative cooling rates at the anode and the cathode were mastered under the various temperatures and air utilizations. At a high temperature the proportion of the evaporative cooling rate to the heat generation rate got higher, the possibility of the evaporative cooling was demonstrated. 2 refs., 7 figs., 1 tab.

  6. Evaporation of Lennard-Jones clusters

    International Nuclear Information System (INIS)

    Roman, C.E.; Garzon, I.L.

    1991-01-01

    Extensive molecular dynamics simulations have been done to study the evaporation of a 13-atom Lennard-Jones cluster. The survival probability and the evaporative lifetime are calculated as a function of the cluster total energy from a classical trajectory analysis. The results are interpreted in terms of the RRK theory of unimolecular dissociation. The calculation of the binding energy of the evaporated species from the evaporation rate and the average kinetic energy release is discussed. (orig.)

  7. Easily controlled dye doped phosphorescent OLEDs with evaporation rate in single furnace

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, Malek; Janghouri, Mohammad; Mohajerani, Ezeddin, E-mail: e-mohajerani@sbu.ac.ir

    2015-04-15

    Electrical and optical characteristic, surface morphology and energy transfer of Ir(ppy){sub 3}:PtTPP were studied as a function of thermal evaporation rate. We have investigated the effect of various evaporation rates for mixture of dyes using single furnace method. When the deposition rate increased from 0.5 to 5 Ǻ/s, the luminescence efficiency, current density and energy transfer of OLED increased. AFM measurements showed that the surface roughness of the Ir(ppy){sub 3}:PtTPP films decreased with increasing deposition rates. These blends show excellent red emitting guest–host system with easier deposition rate control. - Highlights: • Thermal evaporation rate is used to control the doping by using single furnace. • The advantages of using single furnace are discussed. • It is shown that the evaporation rate also affects the surface roughness.

  8. Evaporation and condensation devices for passive heat removal systems in nuclear power engineering

    International Nuclear Information System (INIS)

    Gershuni, A.N.; Pis'mennyj, E.N.; Nishchik, A.P.

    2016-01-01

    The paper justifies advantages of evaporation and condensation heat transfer devices as means of passive heat removal and thermal shielding in nuclear power engineering. The main thermophysical factors that limit heat transfer capacity of evaporation and condensation systems have been examined in the research. The results of experimental studies of heat engineering properties of elongated (8-m) vertically oriented evaporation and condensation devices (two-phase thermosyphons), which showed a high enough heat transfer capacity, as well as stability and reliability both in steady state and in start-up modes, are provided. The paper presents the examples of schematic designs of evaporation and condensation systems for passive heat removal and thermal shielding in application to nuclear power equipment

  9. Optimized evaporative cooling for sodium Bose-Einstein condensation against three-body loss

    International Nuclear Information System (INIS)

    Shobu, Takahiko; Yamaoka, Hironobu; Imai, Hiromitsu; Morinaga, Atsuo; Yamashita, Makoto

    2011-01-01

    We report on a highly efficient evaporative cooling optimized experimentally. We successfully created sodium Bose-Einstein condensates with 6.4x10 7 atoms starting from 6.6x10 9 thermal atoms trapped in a magnetic trap by employing a fast linear sweep of radio frequency at the final stage of evaporative cooling so as to overcome the serious three-body losses. The experimental results such as the cooling trajectory and the condensate growth quantitatively agree with the numerical simulations of evaporative cooling on the basis of the kinetic theory of a Bose gas carefully taking into account our specific experimental conditions. We further discuss theoretically a possibility of producing large condensates, more than 10 8 sodium atoms, by simply increasing the number of initial thermal trapped atoms and the corresponding optimization of evaporative cooling.

  10. New models for droplet heating and evaporation

    KAUST Repository

    Sazhin, Sergei S.; Elwardani, Ahmed Elsaid; Gusev, Ivan G.; Xie, Jianfei; Shishkova, Irina N.; Cao, Bingyang; Snegirev, Alexander Yu.; Heikal, Morgan Raymond

    2013-01-01

    and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono

  11. Evaporation from a sphagnum moss surface

    Science.gov (United States)

    D.S. Nichols; J.M. Brown

    1980-01-01

    Peat cores, 45 cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss surface was greater than that from a free-water surface. Evaporation from the moss increased...

  12. Thermogravimetric analysis of fuel film evaporation

    Institute of Scientific and Technical Information of China (English)

    HU Zongjie; LI Liguang; YU Shui

    2006-01-01

    Thermogravimetric analysis (TGA) was compared with the petrochemical distillation measurement method to better understand the characteristics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different environmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the internal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantificational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, sufficiently high wall temperature is necessary. Evaporation time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evaporation sequence could not be strictly divided according to the boiling points of each component for multicomponent dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

  13. An evaporation driven pump for microfluidics applications

    NARCIS (Netherlands)

    Nie, C.; Mandamparambil, R.; Frijns, A.J.H.; den Toonder, J.M.J.; Tadrist, L.; Graur, I.

    2014-01-01

    We present an evaporation driven micro-pump for micro fluidic applications on a foil. In such a device, the evaporation rate is controlled by the geometry of the channel outlet and its temperature. The evaporation is also influenced by environmental parameters such as air humidity and temperature.

  14. Water Evaporation in Swimming Baths

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik

    This paper is publishing measuring results from models and full-scale baths of the evaporation in swimming baths, both public baths and retraining baths. Moreover, the heat balance of the basin water is measured. In addition the full-scale measurements have given many experiences which are repres......This paper is publishing measuring results from models and full-scale baths of the evaporation in swimming baths, both public baths and retraining baths. Moreover, the heat balance of the basin water is measured. In addition the full-scale measurements have given many experiences which...... are represented in instructions for carrying out and running swimming baths. If you follow the instructions you can achieve less investments, less heat consumption and a better comfort to the bathers....

  15. Black hole evaporation: a paradigm

    International Nuclear Information System (INIS)

    Ashtekar, Abhay; Bojowald, Martin

    2005-01-01

    A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing a possible mechanism for recovery of information that is classically lost in the process of black hole formation. The paradigm is developed directly in the Lorentzian regime and necessary conditions for its viability are discussed. If these conditions are met, much of the tension between expectations based on spacetime geometry and structure of quantum theory would be resolved

  16. Duplex Tear Film Evaporation Analysis.

    Science.gov (United States)

    Stapf, M R; Braun, R J; King-Smith, P E

    2017-12-01

    Tear film thinning, hyperosmolarity, and breakup can cause irritation and damage to the human eye, and these form an area of active investigation for dry eye syndrome research. Recent research demonstrates that deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. In this paper, we explore the conditions for tear film breakup by considering a model for tear film dynamics with two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of osmosis, evaporation as modified by the lipid, and the polar portion of the lipid layer. We solve the system numerically for reasonable parameter values and initial conditions and analyze how shifts in these cause changes to the system's dynamics.

  17. Dew Point Evaporative Comfort Cooling

    Science.gov (United States)

    2012-11-01

    Multiple DASs were installed at Fort Carson, and the data from all the sensors were stored and partially processed on Campbell Scientific Data Loggers. The...evaporative cooling technologies would be expected to easily overcome utility- scale water withdrawal rates. As an example, an evaluation of an...Ambient pressure Outdoor Setra 276 1% of full scale Pyranometer Horizontal Campbell Scientific CS300 5% of daily total The OAT measurement has an

  18. Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud

    OpenAIRE

    Taquet, Vianney; Wirström, Eva; Charnley, Steven B.; Faure, Alexandre; López-Sepulcre, Ana; Persson, Carina M.

    2017-01-01

    Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. We present the detection of the Complex Organic Molecules (COMs) acetaldehyde and methyl formate as w...

  19. Heat loss of heat pipelines in insulation moisture conditions with the evaporation

    Directory of Open Access Journals (Sweden)

    Polovnikov Vyacheslav Yu.

    2014-01-01

    Full Text Available Results of numerical simulation of heat and mass transfer in a wet fibroporous material in conditions of evaporation and steam diffusion were obtained. Values of heat and mass fluxes were established. The contribution of evaporation effect to total heat flux and need to consider volume fractions of water and steam into the structure of fibroporous material in calculation of effective thermal conductivity were shown. Nonstationarity of heat and mass transfer in conditions of considered problem can be ignored.

  20. Experimental results on evaporation waves

    Science.gov (United States)

    Grana Otero, Jose; Parra Fabian, Ignacio

    2010-11-01

    A liquid contained in a vertical glass tube is suddenly depressurized from a high initial pressure down to one for which the stable state is vapour, so vaporization sets off at the free surface. For large enough evaporation rates, the planar vapour-liquid interface is Darrieus-Landau unstable [1], leading to the interface surface rippling close to the instability threshold. Further increasing the initial to final pressure ratio brings about evaporation waves [2,3], in which a highly corrugated front propagates downwards into the liquid. A new experimental method is presented as well as some experimental results obtained by tracking the evolution of the front with a high speed camera. In addition, a number of new phenomena related to the dynamics of bubbles growth at the walls has been uncovered. In particular, a new mode of propagation of the evaporation front is found. In this mode the front originates from below the interface, so the propagation is upwards against gravity with a curved but smooth front.[4pt] [1] F. J. Higuera, Phys. Fluids, V. 30, 679 (1987).[0pt] [2] J.E.Shepherd and B.Sturtevant, J.Fluid Mech., V.121,379 (1982).[0pt] [3] P.Reinke and G.Yadigaroglu, Int.J.Multiph. Flow, V.27,1487 (2001).

  1. Improvements of evaporation drag model

    International Nuclear Information System (INIS)

    Li Xiaoyan; Yang Yanhua; Xu Jijun

    2004-01-01

    A special observable experiment facility has been established, and a series of experiments have been carried out on this facility by pouring one or several high-temperature particles into a water pool. The experiment has verified the evaporation drag model, which believe the non-symmetric profile of the local evaporation rate and the local density of the vapor would bring about a resultant force on the hot particle so as to resist its motion. However, in Yang's evaporation drag model, radiation heat transfer is taken as the only way to transfer heat from hot particle to the vapor-liquid interface and all of the radiation energy is deposited on the vapor-liquid interface, thus contributing to the vaporization rate and mass balance of the vapor film. So, the heat conduction and the heat convection are taken into account in improved model. At the same time, the improved model given by this paper presented calculations of the effect of hot particles temperature on the radiation absorption behavior of water

  2. Cooling clothing utilizing water evaporation

    DEFF Research Database (Denmark)

    Sakoi, Tomonori; Tominaga, Naoto; Melikov, Arsen Krikor

    2014-01-01

    . To prevent wet discomfort, the T-shirt was made of a polyester material having a water-repellent silicon coating on the inner surface. The chest, front upper arms, and nape of the neck were adopted as the cooling areas of the human body. We conducted human subject experiments in an office with air......We developed cooling clothing that utilizes water evaporation to cool the human body and has a mechanism to control the cooling intensity. Clean water was supplied to the outer surface of the T-shirt of the cooling clothing, and a small fan was used to enhance evaporation on this outer surface...... temperature ranging from 27.4 to 30.7 °C to establish a suitable water supply control method. A water supply control method that prevents water accumulation in the T-shirt and water dribbling was validated; this method is established based on the concept of the water evaporation capacity under the applied...

  3. Sampling gaseous compounds from essential oils evaporation by solid phase microextraction devices

    Science.gov (United States)

    Cheng, Wen-Hsi; Lai, Chin-Hsing

    2014-12-01

    Needle trap samplers (NTS) are packed with 80-100 mesh divinylbenzene (DVB) particles to extract indoor volatile organic compounds (VOCs). This study compared extraction efficiency between an NTS and a commercially available 100 μm polydimethylsiloxane-solid phase microextration (PDMS-SPME) fiber sampler used to sample gaseous products in heated tea tree essential oil in different evaporation modes, which were evaporated respectively by free convection inside a glass evaporation dish at 27 °C, by evaporation diffuser at 60 °C, and by thermal ceramic wicks at 100 °C. The experimental results indicated that the NTS performed better than the SPME fiber samplers and that the NTS primarily adsorbed 5.7 ng ethylbenzene, 5.8 ng m/p-xylenes, 11.1 ng 1,2,3-trimethylbenzene, 12.4 ng 1,2,4-trimethylbenzene and 9.99 ng 1,4-diethylbenzene when thermal ceramic wicks were used to evaporate the tea tree essential oil during a 1-hr evaporation period. The experiment also indicated that the temperature used to heat the essential oils should be as low as possible to minimize irritant VOC by-products. If the evaporation temperature does not exceed 100 °C, the concentrations of main by-products trimethylbenzene and diethylbenzene are much lower than the threshold limit values recommended by the National Institute for Occupational Safety and Health (NIOSH).

  4. Evaporation studies of liquid oxide fuel at very high temperatures using laser beam heating

    International Nuclear Information System (INIS)

    Bober, M.; Breitung, W.; Karow, H.U.; Schretzmann, K.

    1976-11-01

    Evaporation experiments with oxide fuel are carried out based laser beam heating of the fuel specimen surface. The measuring quantities are the recoil momentum of the target, the evaporation area, the evaporation time and the mass and momentum of the supersonic vapor jet expanding into vacuum, and the thermal radiation density of the evaporating surface. From the mechanical measuring quantities we derive the vapor pressure of the target material and, in a first approach, also the evaporation temperature by applying a gas dynamic evaluation model. In a second approach, after having measured the spectral emissivity of liquid UO 2 at 633 nm, we determine the evaporation temperature at the liquid surface also from its thermal radiation. For the determination of the vapor pressure from the measured quantities a gas dynamic evaluation model has been developed. An application limit of the measuring technique is given by onset of plasma interaction of the vapor plume with the incident laser beam at temperatures above 4500 K. Experimental values for the saturated vapor pressure of UO 2 are presented, determined from three series of laser evaporation measurements obtained at temperatures around 3500 K, 3950 K, and 4200 K. The average vapor pressures found are 0.6 bar, 3 bar, and 7 bar, respectively. Laser vapor pressure measurements performed by other authors and theoretical extrapolations of the UO 2 vapor pressure curve known from literature show fairly good agreement within their confidence interval with the vapor pressure measurements reported here. (orig./HR) [de

  5. Static, Mixed-Array Total Evaporation for Improved Quantitation of Plutonium Minor Isotopes in Small Samples

    Science.gov (United States)

    Stanley, F. E.; Byerly, Benjamin L.; Thomas, Mariam R.; Spencer, Khalil J.

    2016-06-01

    Actinide isotope measurements are a critical signature capability in the modern nuclear forensics "toolbox", especially when interrogating anthropogenic constituents in real-world scenarios. Unfortunately, established methodologies, such as traditional total evaporation via thermal ionization mass spectrometry, struggle to confidently measure low abundance isotope ratios (evaporation techniques as a straightforward means of improving plutonium minor isotope measurements, which have been resistant to enhancement in recent years because of elevated radiologic concerns. Results are presented for small sample (~20 ng) applications involving a well-known plutonium isotope reference material, CRM-126a, and compared with traditional total evaporation methods.

  6. Variations in isotopic compositions of chlorine in evaporation-controlled salt lake brines of Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Ying-kai; Liu, Wei-guo; Zhou, Y.M.; Wang, Yun-hui; Shirodkar, P.V.

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs sub(2) Cl sup(+) ion by thermal ionization...

  7. Steady state operation of a copper-water LHP with a flat-oval evaporator

    International Nuclear Information System (INIS)

    Becker, S.; Vershinin, S.; Sartre, V.; Laurien, E.; Bonjour, J.; Maydanik, Yu.F.

    2011-01-01

    In order to dissipate the heat generated by electronic boxes in avionic systems, a copper-water LHP with a flat-oval evaporator was fabricated and tested at steady state. The LHP consists of a flat shaped evaporator, 7 mm thick, including compensation chamber with attached heat exchanger. The condenser is cooled by forced convection of liquid. The variable parameters are the heat sink and ambient temperatures (20 and 55 o C), the orientation (-90 o to +90 o in two perpendicular planes) and the power input (0-100 W). Evaporator wall temperatures are higher when the evaporator is placed above the condenser. For heat sink and ambient temperature of 20 o C the evaporator wall temperature does not vary much with heat load for all measured elevations. But it fluctuates at heat sink and ambient temperature equal to 55 o C when the evaporator is placed below the condenser. The LHP total thermal resistance is governed by the condenser resistance. It decreases with increasing heat load, whatever the operating conditions, because the part of the condenser internal surface area used for condensation increases too. A minimum thermal resistance of 0.2 K/W was obtained. The maximum thermal resistance was 2.7 K/W.

  8. Design and development of a split-evaporator heat-pump system

    Energy Technology Data Exchange (ETDEWEB)

    Somerville, M.H.; Penoncello, S.G.

    1981-12-01

    The designs and experimental results of three types of multiple source heat pumps are presented. The three designs are the parallel evaporator, the series evaporator, and the parallel evaporator with active subcooling, with the parallel evaporator with the active subcooling showing the most promise for solving the problem of defrosting of air evaporators. Three design procedures for multiple source heat pumps were developed. One of these is a hand calculational procedure, the others are computer based. The models are based upon the refrigerant flow rate, rather than the refrigeration effect of the evaporator. The technical results of a detailed analytical and experimental model of the heat transfer rates on a flat plate ice maker are presented. It is shown, both analytically and experimentally, that the temperature of the air surrounding the flat plate ice maker can play a dominant role in the rate of ice formation. A detailed weather analysis for forty cities located throughout the nation was completed. These data were processed to allow easy computation of thermal storage requirements for full, partial, or minimum ACES systems, or upon other design requirements, such as off-peak air conditioning. The results of an innovative ice storage system that is thermally coupled to the earth are described. This system has the potential for meeting both the off-peak air conditioning needs and the thermal storage requirements for the heating cycle. An economic and energy comparison of multiple source heat pumps with ACES, and air-to-air heat pump systems is presented.

  9. Heat and mass transfer analogies for evaporation models at high evaporation rate

    OpenAIRE

    Trontin , P.; Villedieu , P.

    2014-01-01

    International audience; In the framework of anti and deicing applications, heated liquid films can appear above the ice thickness, or directly above the wall. Then, evaporation plays a major role in the Messinger balance and evaporated mass has to be predicted accurately. Unfortunately, it appears that existing models under-estimate evaporation at high temperature. In this study, different evaporation models at high evaporation rates are studied. The different hypothesis on which these models...

  10. Does evaporation paradox exist in China?

    Directory of Open Access Journals (Sweden)

    Z. T. Cong

    2009-03-01

    Full Text Available One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called "evaporation paradox". Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The conclusions include: (1 From 1956 to 2005, pan evaporation paradox existed in China as a whole while pan evaporation kept decreasing and air temperature became warmer and warmer, but it does not apply to Northeast and Southeast China; (2 From 1956 to 1985, pan evaporation paradox existed narrowly as a whole with unobvious climate warming trend, but it does not apply to Northeast China; (3 From 1986 to 2005, in the past 20 years, pan evaporation paradox did not exist for the whole period while pan evaporation kept increasing, although it existed in South China. Furthermore, the trend of other weather factors including sunshine duration, windspeed, humidity and vapor pressure deficit, and their relations with pan evaporation are discussed. As a result, it can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the decreasing in vapor pressure deficit due to strong warming after 1986. With the Budyko curve, it can be concluded that the actual evaporation decreased in the former 30 years and increased in the latter 20 year for the whole China.

  11. ANALYSIS AND MODELING OF SOLAR EVAPORATOR-COLLECTOR

    Directory of Open Access Journals (Sweden)

    Zakaria Mohd. Amin

    2015-11-01

    Full Text Available Solar energy is considered a sustainable resource that poses little to no harmful effects on the environment. The performance of a solar system depends to a great extent on the collector used for the conversion of solar radiant energy to thermal energy. A solar evaporator-collector (SEC is basically an unglazed flat plate collector where refrigerants, such as R134a is used as the working fluid. As the operating temperature of the SEC is very low, it utilizes both solar irradiation and ambient energy leading to a much higher efficiency than the conventional collectors. This capability of SECs to utilize ambient energy also enables the system to operate at night. This type of collector can be locally made and is relatively much cheaper than the conventional collector.   At the National University of Singapore, the evaporator-collector was integrated to a heat pump and the performance was investigated for several thermal applications: (i water heating, (ii drying and (iii desalination. A 2-dimensional transient mathematical model of this system was developed and validated by experimental data. The present study provides a comprehensive study of performance. KEYWORDS: heat pump; evaporator-collector.

  12. Mobile evaporator corrosion test results

    International Nuclear Information System (INIS)

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80 degrees C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either open-quotes satisfactoryclose quotes (2-20 mpy) or open-quotes excellentclose quotes (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment

  13. Evaporation From Soil Containers With Irregular Shapes

    Science.gov (United States)

    Assouline, Shmuel; Narkis, Kfir

    2017-11-01

    Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

  14. Evaporative Heat Transfer Mechanisms within a Heat Melt Compactor

    Science.gov (United States)

    Golliher, Eric L.; Gotti, Daniel J.; Rymut, Joseph Edward; Nguyen, Brian K; Owens, Jay C.; Pace, Gregory S.; Fisher, John W.; Hong, Andrew E.

    2013-01-01

    This paper will discuss the status of microgravity analysis and testing for the development of a Heat Melt Compactor (HMC). Since fluids behave completely differently in microgravity, the evaporation process for the HMC is expected to be different than in 1-g. A thermal model is developed to support the design and operation of the HMC. Also, low-gravity aircraft flight data is described to assess the point at which water may be squeezed out of the HMC during microgravity operation. For optimum heat transfer operation of the HMC, the compaction process should stop prior to any water exiting the HMC, but nevertheless seek to compact as much as possible to cause high heat transfer and therefore shorter evaporation times.

  15. Microporous Cokes Formed in Zeolite Catalysts Enable Efficient Solar Evaporation

    KAUST Repository

    Wang, Jianjian

    2017-03-13

    Cokes are inevitably generated during zeolite-catalyzed reactions as deleterious side products that deactivate the catalyst. In this study, we in-situ converted cokes into carbons within the confined microporous zeolite structures and evaluated their performances as absorbing materials for solar-driven water evaporation. With a properly chosen zeolite, the cokederived carbons possessed ordered interconnected pores and tunable compositions. We found that the porous structure and the oxygen content in as-prepared carbons had important influences on their energy conversion efficiencies. Among various investigated carbon materials, the carbon derived from the methanol-to-olefins reaction over zeolite Beta gave the highest conversion efficiency of 72% under simulated sunlight with equivalent solar intensity of 2 suns. This study not only demonstrates the great potential of traditionally useless cokes for solar thermal applications but also provides new insights into the design of carbon-based absorbing materials for efficient solar evaporation.

  16. Some cosmological consequences of primordial black-hole evaporations

    International Nuclear Information System (INIS)

    Carr, B.J.

    1976-01-01

    According to Hawking, primordial black holes of less than 10 15 g would have evaporated by now. This paper examines the way in which small primordial black holes could thereby have contributed to the background density of photons, nucleons, neutrinos, electrons, and gravitons in the universe. Any photons emitted late enough should maintain their emission temperature apart from a redshift effect: it is shown that the biggest contribution should come from primordial black holes of about 10 15 g, which evaporate in the present era, and it is argued that observations of the γ-ray background indicate that primordial black holes of this size must have a mean density less than 10 -8 times the critical density. Photons which were emitted sufficiently early to be thermalized could, in principle, have generated the 3 K background in an initially cold universe, but only if the density fluctuations in the early universe had a particular form and did not extend up to a mass scale of 10 15 g. Primordial black holes of less than 10 14 g should emit nucleons: it is shown that such nucleons could not contribute appreciably to the cosmic-ray background. However, nucleon emission could have generated the observed number density of baryons in an initially baryon-symmetric universe, provided some CP-violating process operates in black hole evaporations such that more baryons are always produced than antibaryons. We predict the spectrum of neutrinos, electrons, and gravitons which should result from primordial black-hole evaporations and show that the observational limits on the background electron flux might place a stronger limitation on the number of 10 15 g primordial black holes than the γ-ray observations. Finally, we examine the limits that various observations place on the strength of any long-range baryonic field whose existence might be hypothesized as a means of preserving baryon number in black-hole evaporations

  17. Transient Stefan flow and thermophoresis around an evaporating droplet

    International Nuclear Information System (INIS)

    Vittori, O.

    1984-01-01

    The particle scavening efficiency of vapour-grown ice crystals falling from mixed clouds proves to be very high. Stefan flow, an aerodynamic flow originating in the fluid surrounding evaporating or condensing bodies, pushes airborne particles away from the surface of the supercooled droplets evaporating in the vicinity of an ice crystal. The particle Brownian flux towards the surface of the ice crystal (terminal velocity of about 1 m s -1 ) is, therefore, enhanced. However, the efficiency of this process of airborne-particle removal is strongly reduced as a consequence of the cooling of the evaporating droplet which produces a ''thermal force'', thermophoresis, which counteracts the particle Stefan flow. At the surface of an evaporating droplet in a quasi-equilibrium state, the two airborne-particle velocity fields practically balance each other. This counteracting effect on particle motion needs to be evaluated in the transient case. An approach is presented which consists of reformulating the transient heat and mass transfer problem in such a way as to convert it into a purely heat transfer problem having a known analytical solution. The approach is discussed and found to be correct. The results of the computations show that the counteracting role of thermophoresis on Stefan-flow particle motion during the residence time of supercooled droplets in the vicinity of an ice crystal (from 10 -5 to 10 -4 s), which is also the time in which evaporation takes place, is considerably weak. It turns out to be practically negligible for large droplets (radius >= 8x10 -4 cm)

  18. Quantized evaporation from liquid helium

    Science.gov (United States)

    Baird, M. J.; Hope, F. R.; Wyatt, A. F. G.

    1983-07-01

    The atomic-level kinetics of evaporation from a liquid surface are investigated experimentally for the case of liquid He-4. A pulse of phonons was injected by a submerged thin-film heater into purified He-4 (cooled to less than about 0.1 K) and collimated into a beam directed at the liquid surface; the atoms liberated at the surface were detected by a bolometer. The energy of the incident phonon and the kinetic energy of the liberated atom were calculated by determining the group velocity (from the minimum time elapsed between the beginning of the heater pulse and the arrival of the leading edge of the signal) and combining it with neutron-measured excitation dispersion data. Measurements were also made with a mixture of He-3 and He-4. The results are shown to be in good agreement with theoretical predictions of the phonon-induced quantum evaporation of surface atoms: the energy of the phonon is divided between the kinetic energy of the liberated atom and the energy required to overcome the binding forces.

  19. Evaporator modeling - A hybrid approach

    International Nuclear Information System (INIS)

    Ding Xudong; Cai Wenjian; Jia Lei; Wen Changyun

    2009-01-01

    In this paper, a hybrid modeling approach is proposed to model two-phase flow evaporators. The main procedures for hybrid modeling includes: (1) Based on the energy and material balance, and thermodynamic principles to formulate the process fundamental governing equations; (2) Select input/output (I/O) variables responsible to the system performance which can be measured and controlled; (3) Represent those variables existing in the original equations but are not measurable as simple functions of selected I/Os or constants; (4) Obtaining a single equation which can correlate system inputs and outputs; and (5) Identify unknown parameters by linear or nonlinear least-squares methods. The method takes advantages of both physical and empirical modeling approaches and can accurately predict performance in wide operating range and in real-time, which can significantly reduce the computational burden and increase the prediction accuracy. The model is verified with the experimental data taken from a testing system. The testing results show that the proposed model can predict accurately the performance of the real-time operating evaporator with the maximum error of ±8%. The developed models will have wide applications in operational optimization, performance assessment, fault detection and diagnosis

  20. Molecular characterization and volatility evolution of α-pinene ozonolysis SOA during isothermal evaporations

    Science.gov (United States)

    D'Ambro, E.; Schobesberger, S.; Lopez-Hilfiker, F.; Shilling, J. E.; Lee, B. H.; Thornton, J. A.

    2017-12-01

    α-Pinene (C10H16), the most abundantly emitted monoterpene, is a large contributor to global biogenic secondary organic aerosol (SOA) budgets due to its high SOA yields upon oxidation. We probe the volatility and evaporation behavior upon dilution of α-pinene SOA to further our understanding of the nascent volatility distribution, viscosity, and how these evolve in time absent photochemical oxidation. We present molecular composition measurements of the gas and particle phases of α-pinene ozonolysis SOA formed at 0% and 50% relative humidity (RH), followed by room-temperature evaporation in ultra-high purity N2 humidified to 20-90% RH. Experiments were performed in the Pacific Northwest National Laboratory 10.6 m3 and the University of Washington 0.7 m3 environmental chambers utilizing a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time of flight chemical ionization mass spectrometer utilizing iodide adduct ionization. We present novel insights into the total mass that evaporates as a function of time from 10 min to 24 hours without heating, the molecular speciation of the evaporate, as well as the effective volatility and composition of the SOA mass remaining. Consistent with previous studies, we find two stages of evaporation: a rapid loss of a large portion of the total signal over the course of ≤3 hours, followed by a stage of much slower evaporation over the proceeding 21 hours. Varying the RH of formation effects evaporation rate on timescales ≤3 hours, however the mass fraction remaining after 24 hours converges to 30-50% under all formation and evaporation RHs. We simulate the evaporation behavior and remaining fractions desorbed via temperature programmed thermal desorption to derive effective saturation vapor concentrations, mass accommodation coefficients, and rates of chemical evolution producing both higher and lower volatility components during the evaporation time period.

  1. New models for droplet heating and evaporation

    KAUST Repository

    Sazhin, Sergei S.

    2013-02-01

    A brief summary of new models for droplet heating and evaporation, developed mainly at the Sir Harry Ricardo Laboratory of the University of Brighton during 2011-2012, is presented. These are hydrodynamic models for mono-component droplet heating and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono-component droplet heating and evaporation, and a model for mono-component droplet evaporation, based on molecular dynamics simulation. The results, predicted by the new models are compared with experimental data and the prehctions of the previously developed models where possible. © 2013 Asian Network for Scientific Information.

  2. Wetting and evaporation of binary mixture drops.

    Science.gov (United States)

    Sefiane, Khellil; David, Samuel; Shanahan, Martin E R

    2008-09-11

    Experimental results on the wetting behavior of water, methanol, and binary mixture sessile drops on a smooth, polymer-coated substrate are reported. The wetting behavior of evaporating water/methanol drops was also studied in a water-saturated environment. Drop parameters (contact angle, shape, and volume) were monitored in time. The effects of the initial relative concentrations on subsequent evaporation and wetting dynamics were investigated. Physical mechanisms responsible for the various types of wetting behavior during different stages are proposed and discussed. Competition between evaporation and hydrodynamic flow are evoked. Using an environment saturated with water vapor allowed further exploration of the controlling mechanisms and underlying processes. Wetting stages attributed to differential evaporation of methanol were identified. Methanol, the more volatile component, evaporates predominantly in the initial stage. The data, however, suggest that a small proportion of methanol remained in the drop after the first stage of evaporation. This residual methanol within the drop seems to influence subsequent wetting behavior strongly.

  3. Is evaporative colling important for shallow clouds?

    Science.gov (United States)

    Gentine, P.; Park, S. B.; Davini, P.; D'Andrea, F.

    2017-12-01

    We here investigate and test using large-eddy simulations the hypothesis that evaporative cooling might not be crucial for shallow clouds. Results from various Shallow convection and stratocumulus LES experiments show that the influence of evaporative cooling is secondary compared to turbulent mixing, which dominates the buoyancy reversal. In shallow cumulus subising shells are not due to evaporative cooling but rather reflect a vortical structure, with a postive buoyancy anomaly in the core due to condensation. Disabling evaporative cooling has negligible impact on this vortical structure and on buoyancy reversal. Similarly in non-precipitating stratocumuli evaporative cooling is negeligible copmared to other factors, especially turbulent mixing and pressure effects. These results emphasize that it may not be critical to icnlude evaporative cooling in parameterizations of shallow clouds and that it does not alter entrainment.

  4. Atmospheric impacts of evaporative cooling systems

    International Nuclear Information System (INIS)

    Carson, J.E.

    1976-10-01

    The report summarizes available information on the effects of various power plant cooling systems on the atmosphere. While evaporative cooling systems sharply reduce the biological impacts of thermal discharges in water bodies, they create (at least, for heat-release rates comparable to those of two-unit nuclear generating stations) atmospheric changes. For an isolated site such as required for a nuclear power plant, these changes are rather small and local, and usually environmentally acceptable. However, one cannot say with certainty that these effects will remain small as the number of reactors on a given site increases. There must exist a critical heat load for a specific site which, if exceeded, can create its own weather patterns, and thus create inadvertent weather changes such as rain and snow, severe thunderstorms, and tornadoes. Because proven mathematical models are not available, it is not now possible to forecast precisely the extent and frequency of the atmospheric effects of a particular heat-dissipation system at a particular site. Field research on many aspects of cooling system operation is needed in order to document and quantify the actual atmospheric changes caused by a given cooling system and to provide the data needed to develop and verify mathematical and physical models. The more important topics requiring field study are plume rise, fogging and icing (from certain systems), drift emission and deposition rates, chemical interactions, cloud and precipitation formation and critical heat-release rates

  5. Sessile Drop Evaporation and Leidenfrost Phenomenon

    OpenAIRE

    A. K. Mozumder; M. R. Ullah; A. Hossain; M. A. Islam

    2010-01-01

    Problem statement: Quenching and cooling are important process in manufacturing industry for controlling the mechanical properties of materials, where evaporation is a vital mode of heat transfer. Approach: This study experimentally investigated the evaporation of sessile drop for four different heated surfaces of Aluminum, Brass, Copper and Mild steel with a combination of four different liquids as Methanol, Ethanol, Water and NaCl solution. The time of evaporation for the droplet on the hot...

  6. Modeling of Heating and Evaporation of FACE I Gasoline Fuel and its Surrogates

    KAUST Repository

    Elwardani, Ahmed Elsaid

    2016-04-05

    The US Department of Energy has formulated different gasoline fuels called \\'\\'Fuels for Advanced Combustion Engines (FACE)\\'\\' to standardize their compositions. FACE I is a low octane number gasoline fuel with research octane number (RON) of approximately 70. The detailed hydrocarbon analysis (DHA) of FACE I shows that it contains 33 components. This large number of components cannot be handled in fuel spray simulation where thousands of droplets are directly injected in combustion chamber. These droplets are to be heated, broken-up, collided and evaporated simultaneously. Heating and evaporation of single droplet FACE I fuel was investigated. The heating and evaporation model accounts for the effects of finite thermal conductivity, finite liquid diffusivity and recirculation inside the droplet, referred to as the effective thermal conductivity/effective diffusivity (ETC/ED) model. The temporal variations of the liquid mass fractions of the droplet components were used to characterize the evaporation process. Components with similar evaporation characteristics were merged together. A representative component was initially chosen based on the highest initial mass fraction. Three 6 components surrogates, Surrogate 1-3, that match evaporation characteristics of FACE I have been formulated without keeping same mass fractions of different hydrocarbon types. Another two surrogates (Surrogate 4 and 5) were considered keeping same hydrocarbon type concentrations. A distillation based surrogate that matches measured distillation profile was proposed. The calculated molar mass, hydrogen-to-carbon (H/C) ratio and RON of Surrogate 4 and distillation based one are close to those of FACE I.

  7. Portable brine evaporator unit, process, and system

    Science.gov (United States)

    Hart, Paul John; Miller, Bruce G.; Wincek, Ronald T.; Decker, Glenn E.; Johnson, David K.

    2009-04-07

    The present invention discloses a comprehensive, efficient, and cost effective portable evaporator unit, method, and system for the treatment of brine. The evaporator unit, method, and system require a pretreatment process that removes heavy metals, crude oil, and other contaminates in preparation for the evaporator unit. The pretreatment and the evaporator unit, method, and system process metals and brine at the site where they are generated (the well site). Thus, saving significant money to producers who can avoid present and future increases in transportation costs.

  8. Conical evaporator and liquid-return wick model for vapor anode, multi-tube AMTEC cells

    Science.gov (United States)

    Tournier, Jean-Michel; El-Genk, Mohamed S.

    2000-01-01

    A detailed, 2-D thermal-hydraulic model for conical and flat evaporators and the liquid sodium return artery in PX-type AMTEC cells was developed, which predicts incipient dryout at the evaporator wick surface. Results obtained at fixed hot and cold side temperatures showed that the flat evaporator provided a slightly lower vapor pressure, but reached the capillary limit at higher temperature. The loss of performance due to partial recondensation over up to 20% of the wick surface of the deep conical evaporators was offset by the larger surface area available for evaporation, providing a slightly higher vapor pressure. Model results matched the PX-3A cell's experimental data of electrical power output, but the predicted temperature of the cell's conical evaporator was consistently ~50 K above measurements. A preliminary analysis indicated that sodium vapor leakage in the cell (through microcracks in the BASE tubes' walls or brazes) may explain the difference between predicted and measured evaporator temperatures in PX-3A. .

  9. Experimental Investigation Evaporation of Liquid Mixture Droplets during Depressurization into Air Stream

    Science.gov (United States)

    Liu, L.; Bi, Q. C.; Terekhov, Victor I.; Shishkin, Nikolay E.

    2010-03-01

    The objective of this study is to develop experimental method to study the evaporation process of liquid mixture droplets during depressurization and into air stream. During the experiment, a droplet was suspended on a thermocouple; an infrared thermal imager was used to measure the droplet surface temperature transition. Saltwater droplets were used to investigate the evaporation process during depressurization, and volatile liquid mixtures of ethanol, methanol and acetone in water were applied to experimentally research the evaporation into air stream. According to the results, the composition and concentration has a complex influence on the evaporation rate and the temperature transition. With an increase in the share of more volatile component, the evaporation rate increases. While, a higher salt concentration in water results in a lower evaporation rate. The shape variation of saltwater droplet also depends on the mass concentration in solution, whether it is higher or lower than the eutectic point (22.4%). The results provide important insight into the complex heat and mass transfer of liquid mixture during evaporation.

  10. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

  11. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  12. Performance of evaporator-collector and air collector in solar assisted heat pump dryer

    International Nuclear Information System (INIS)

    Hawlader, M.N.A.; Rahman, S.M.A.; Jahangeer, K.A.

    2008-01-01

    A solar assisted heat pump dryer has been designed, fabricated and tested. This paper presents the performance of the evaporator-collector and the air collector when operated under the same meteorological conditions. ASHRAE standard procedure for collector testing has been followed. The evaporator-collector of the heat pump is acting directly as the solar collector, and the temperature of the refrigerant at the inlet to the evaporator-collector always remained below the ambient temperature. Because of the rejection of sensible and latent heats of air at the dehumidifier, the temperature at the inlet to the air collector is lower than that of the ambient air. Hence, the thermal efficiency of the air collector also increases due to a reduction of losses from the collector. The efficiencies of the evaporator-collector and the air collector were found to vary between 0.8-0.86 and 0.7-0.75, respectively, when operated under the meteorological conditions of Singapore

  13. Detailed finite element method modeling of evaporating multi-component droplets

    Energy Technology Data Exchange (ETDEWEB)

    Diddens, Christian, E-mail: C.Diddens@tue.nl

    2017-07-01

    The evaporation of sessile multi-component droplets is modeled with an axisymmetic finite element method. The model comprises the coupled processes of mixture evaporation, multi-component flow with composition-dependent fluid properties and thermal effects. Based on representative examples of water–glycerol and water–ethanol droplets, regular and chaotic examples of solutal Marangoni flows are discussed. Furthermore, the relevance of the substrate thickness for the evaporative cooling of volatile binary mixture droplets is pointed out. It is shown how the evaporation of the more volatile component can drastically decrease the interface temperature, so that ambient vapor of the less volatile component condenses on the droplet. Finally, results of this model are compared with corresponding results of a lubrication theory model, showing that the application of lubrication theory can cause considerable errors even for moderate contact angles of 40°. - Graphical abstract:.

  14. Entropy Budget for Hawking Evaporation

    Directory of Open Access Journals (Sweden)

    Ana Alonso-Serrano

    2017-07-01

    Full Text Available Blackbody radiation, emitted from a furnace and described by a Planck spectrum, contains (on average an entropy of 3 . 9 ± 2 . 5 bits per photon. Since normal physical burning is a unitary process, this amount of entropy is compensated by the same amount of “hidden information” in correlations between the photons. The importance of this result lies in the posterior extension of this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget for the evaporation process. In order to carry out this calculation, we adopt a variant of the “average subsystem” approach, but consider a tripartite pure system that includes the influence of the rest of the universe, and which allows “young” black holes to still have a non-zero entropy; which we identify with the standard Bekenstein entropy.

  15. Organic evaporator steam valve failure

    International Nuclear Information System (INIS)

    Jacobs, R.A.

    1992-01-01

    Defense Waste Processing Facility (DWPF) Technical has requested an analysis of the capacity of the Organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore, it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS)

  16. Intrinsic Evaporative Cooling by Hygroscopic Earth Materials

    Directory of Open Access Journals (Sweden)

    Alexandra R. Rempel

    2016-08-01

    Full Text Available The phase change of water from liquid to vapor is one of the most energy-intensive physical processes in nature, giving it immense potential for cooling. Diverse evaporative cooling strategies have resulted worldwide, including roof ponds and sprinklers, courtyard fountains, wind catchers with qanats, irrigated green roofs, and fan-assisted evaporative coolers. These methods all require water in bulk liquid form. The evaporation of moisture that has been sorbed from the atmosphere by hygroscopic materials is equally energy-intensive, however, yet has not been examined for its cooling potential. In arid and semi-arid climates, hygroscopic earth buildings occur widely and are known to maintain comfortable indoor temperatures, but evaporation of moisture from their walls and roofs has been regarded as unimportant since water scarcity limits irrigation and rainfall; instead, their cool interiors are attributed to well-established mass effects in delaying the transmission of sensible gains. Here, we investigate the cooling accomplished by daily cycles of moisture sorption and evaporation which, requiring only ambient humidity, we designate as “intrinsic” evaporative cooling. Connecting recent soil science to heat and moisture transport studies in building materials, we use soils, adobe, cob, unfired earth bricks, rammed earth, and limestone to reveal the effects of numerous parameters (temperature and relative humidity, material orientation, thickness, moisture retention properties, vapor diffusion resistance, and liquid transport properties on the magnitude of intrinsic evaporative cooling and the stabilization of indoor relative humidity. We further synthesize these effects into concrete design guidance. Together, these results show that earth buildings in diverse climates have significant potential to cool themselves evaporatively through sorption of moisture from humid night air and evaporation during the following day’s heat. This finding

  17. Ionic solubility and solutal advection governed augmented evaporation kinetics of salt solution pendant droplets

    Science.gov (United States)

    Jaiswal, Vivek; Harikrishnan, A. R.; Khurana, Gargi; Dhar, Purbarun

    2018-01-01

    The presence of dispersed inclusions is known to modify the interfacial characteristics in liquids by adsorption-desorption of the ions at interfaces. The present article reports the influencing role of dissolved ions in a polar fluid on its evaporation dynamics. The evaporation dynamics of pendant droplets of aqueous solutions of variant simple salts and concentrations have been experimentally studied. The presence of salts is observed to enhance the evaporation rate (obeying the classical D2 law), and the enhancement has been found to hold a direct proportionality to the concentration of the dissolved salt. Furthermore, it is observed that the degree of enhancement in the evaporation rate is also directly proportional to the solubility of the salt in question. The phenomenon is explained based on the chemical kinetics and thermodynamics of hydration of the ionic species in the polar fluid. The classical evaporation rate constant formulation is found to be inadequate in modeling the enhanced species transport. Additional probing via particle image velocimetry reveals augmented internal circulation within the evaporating salt based drops compared to pure water. Mapping the dynamic surface tension reveals that a salt concentration gradient is generated between the bulk and periphery of the droplet and it could be responsible for the internal advection cells visualized. A thermo-solutal Marangoni and Rayleigh convection based mathematical formulation has been put forward, and it is shown that the enhanced solute-thermal convection could play a major role in enhanced evaporation. The internal circulation mapped from experiments is found to be in good quantitative agreement with the model predictions. Scaling analysis further reveals that the stability of the solutal Marangoni convection surpasses the thermal counterpart with higher salt concentration and solubility. The present article sheds insight into the possible domineering role of conjugate thermohydraulic and

  18. Analytical Model for Diffusive Evaporation of Sessile Droplets Coupled with Interfacial Cooling Effect.

    Science.gov (United States)

    Nguyen, Tuan A H; Biggs, Simon R; Nguyen, Anh V

    2018-05-30

    Current analytical models for sessile droplet evaporation do not consider the nonuniform temperature field within the droplet and can overpredict the evaporation by 20%. This deviation can be attributed to a significant temperature drop due to the release of the latent heat of evaporation along the air-liquid interface. We report, for the first time, an analytical solution of the sessile droplet evaporation coupled with this interfacial cooling effect. The two-way coupling model of the quasi-steady thermal diffusion within the droplet and the quasi-steady diffusion-controlled droplet evaporation is conveniently solved in the toroidal coordinate system by applying the method of separation of variables. Our new analytical model for the coupled vapor concentration and temperature fields is in the closed form and is applicable for a full range of spherical-cap shape droplets of different contact angles and types of fluids. Our analytical results are uniquely quantified by a dimensionless evaporative cooling number E o whose magnitude is determined only by the thermophysical properties of the liquid and the atmosphere. Accordingly, the larger the magnitude of E o , the more significant the effect of the evaporative cooling, which results in stronger suppression on the evaporation rate. The classical isothermal model is recovered if the temperature gradient along the air-liquid interface is negligible ( E o = 0). For substrates with very high thermal conductivities (isothermal substrates), our analytical model predicts a reversal of temperature gradient along the droplet-free surface at a contact angle of 119°. Our findings pose interesting challenges but also guidance for experimental investigations.

  19. CoPt nanoparticles deposited by electron beam evaporation

    International Nuclear Information System (INIS)

    Castaldi, L.; Giannakopoulos, K.; Travlos, A.; Niarchos, D.; Boukari, S.; Beaurepaire, E.

    2005-01-01

    Co 50 Pt 50 nanoparticles were co-deposited on thermally oxidized Si substrates by electron beam evaporation at 750 deg C. The mean particle sizes are between ∼5 and ∼20 nm and depend on the nominal thickness of the layer. Different processing conditions resulted in different structural and morphological properties of the samples which led to superparamagnetic and ferromagnetic behaviors. The post-annealing treatment of the CoPt nanograins resulted in the crystallization of the L1 0 ordered phase and in the magnetic hardening of nanoparticles with a maximum coercivity of ∼7.4 kOe

  20. Sequence crystallization during isotherm evaporation of southern ...

    African Journals Online (AJOL)

    Southern Algerian's natural brine sampled from chott Baghdad may be a source of mineral salts with a high economic value. These salts are recoverable by simple solar evaporation. Indeed, during isothermal solar evaporation, it is possible to recover mineral salts and to determine the precipitation sequences of different ...

  1. Odors from evaporation of acidified pig urine

    NARCIS (Netherlands)

    Willers, H.C.; Hobbs, P.J.; Ogink, N.W.M.

    2004-01-01

    In the Dutch Hercules project feces and urine from pigs are collected separately underneath the slatted floor in a pig house and treated in two processes. Feces are composted and urine is concentrated by water evaporation in a packed bed. Exhaust air from the pig house is used for the evaporation in

  2. 21 CFR 131.130 - Evaporated milk.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Evaporated milk. 131.130 Section 131.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.130 Evaporated milk. (a...

  3. Water evaporation: a transition path sampling study.

    Science.gov (United States)

    Varilly, Patrick; Chandler, David

    2013-02-07

    We use transition path sampling to study evaporation in the SPC/E model of liquid water. On the basis of thousands of evaporation trajectories, we characterize the members of the transition state ensemble (TSE), which exhibit a liquid-vapor interface with predominantly negative mean curvature at the site of evaporation. We also find that after evaporation is complete, the distributions of translational and angular momenta of the evaporated water are Maxwellian with a temperature equal to that of the liquid. To characterize the evaporation trajectories in their entirety, we find that it suffices to project them onto just two coordinates: the distance of the evaporating molecule to the instantaneous liquid-vapor interface and the velocity of the water along the average interface normal. In this projected space, we find that the TSE is well-captured by a simple model of ballistic escape from a deep potential well, with no additional barrier to evaporation beyond the cohesive strength of the liquid. Equivalently, they are consistent with a near-unity probability for a water molecule impinging upon a liquid droplet to condense. These results agree with previous simulations and with some, but not all, recent experiments.

  4. An evaporation based digital microflow meter

    NARCIS (Netherlands)

    Nie, C; Frijns, A J H; Mandamparambil, R; Zevenbergen, M A G; den Toonder, J M J

    2015-01-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes

  5. An evaporation based digital microflow meter

    NARCIS (Netherlands)

    Nie, C.; Frijns, A.J.H.; Mandamparambil, R.; Zevenbergen, M.A.G.; Toonder, den J.M.J.

    2015-01-01

    In this work, we present a digital microflow meter operating in the range 30–250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes

  6. 242-A evaporator vacuum condenser system

    International Nuclear Information System (INIS)

    Smith, V.A.

    1994-01-01

    This document is written for the 242-A evaporator vacuum condenser system (VCS), describing its purpose and operation within the evaporator. The document establishes the operating parameters specifying pressure, temperature, flow rates, interlock safety features and interfacing sub-systems to support its operation

  7. Advanced evaporator technology progress report FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlain, D.; Hutter, J.C.; Leonard, R.A. [and others

    1995-01-01

    This report summarizes the work that was completed in FY 1992 on the program {open_quotes}Technology Development for Concentrating Process Streams.{close_quotes} The purpose of this program is to evaluate and develop evaporator technology for concentrating radioactive waste and product streams such as those generated by the TRUEX process. Concentrating these streams and minimizing the volume of waste generated can significantly reduce disposal costs; however, equipment to concentrate the streams and recycle the decontaminated condensates must be installed. LICON, Inc., is developing an evaporator that shows a great deal of potential for this application. In this report, concepts that need to be incorporated into the design of an evaporator operated in a radioactive environment are discussed. These concepts include criticality safety, remote operation and maintenance, and materials of construction. Both solubility and vapor-liquid equilibrium data are needed to design an effective process for concentrating process streams. Therefore, literature surveys were completed and are summarized in this report. A model that is being developed to predict vapor phase compositions is described. A laboratory-scale evaporator was purchased and installed to study the evaporation process and to collect additional data. This unit is described in detail. Two new LICON evaporators are being designed for installation at Argonne-East in FY 1993 to process low-level radioactive waste generated throughout the laboratory. They will also provide operating data from a full-sized evaporator processing radioactive solutions. Details on these evaporators are included in this report.

  8. Shadow mask evaporation through monolayer modified nanostencils

    NARCIS (Netherlands)

    Kolbel, M.; Tjerkstra, R.W.; Brugger, J.P.; van Rijn, C.J.M.; Nijdam, W.; Huskens, Jurriaan; Reinhoudt, David

    2002-01-01

    Gradual clogging of the apertures of nanostencils used as miniature shadow masks in metal evaporations can be reduced by coating the stencil with self-assembled monolayers (SAM). This is quantified by the dimensions (height and volume) of gold features obtained by nanostencil evaporation as measured

  9. Advanced evaporator technology progress report FY 1992

    International Nuclear Information System (INIS)

    Chamberlain, D.; Hutter, J.C.; Leonard, R.A.

    1995-01-01

    This report summarizes the work that was completed in FY 1992 on the program open-quotes Technology Development for Concentrating Process Streams.close quotes The purpose of this program is to evaluate and develop evaporator technology for concentrating radioactive waste and product streams such as those generated by the TRUEX process. Concentrating these streams and minimizing the volume of waste generated can significantly reduce disposal costs; however, equipment to concentrate the streams and recycle the decontaminated condensates must be installed. LICON, Inc., is developing an evaporator that shows a great deal of potential for this application. In this report, concepts that need to be incorporated into the design of an evaporator operated in a radioactive environment are discussed. These concepts include criticality safety, remote operation and maintenance, and materials of construction. Both solubility and vapor-liquid equilibrium data are needed to design an effective process for concentrating process streams. Therefore, literature surveys were completed and are summarized in this report. A model that is being developed to predict vapor phase compositions is described. A laboratory-scale evaporator was purchased and installed to study the evaporation process and to collect additional data. This unit is described in detail. Two new LICON evaporators are being designed for installation at Argonne-East in FY 1993 to process low-level radioactive waste generated throughout the laboratory. They will also provide operating data from a full-sized evaporator processing radioactive solutions. Details on these evaporators are included in this report

  10. Floating convection barrier for evaporation source

    International Nuclear Information System (INIS)

    1975-01-01

    A floating matrix of titanium in an uranium evaporation source, melted by an electron beam, serves as a barrier for preventing cooler material from reaching the evaporation area. This construction allows a big volume of melted uranium to be present and new uranium to be furnished in regulated intervals without manual intervention

  11. Evaporation experiments and modelling for glass melts

    NARCIS (Netherlands)

    Limpt, J.A.C. van; Beerkens, R.G.C.

    2007-01-01

    A laboratory test facility has been developed to measure evaporation rates of different volatile components from commercial and model glass compositions. In the set-up the furnace atmosphere, temperature level, gas velocity and batch composition are controlled. Evaporation rates have been measured

  12. Modelling and performance of heat pipes with long evaporator sections

    Science.gov (United States)

    Wits, Wessel W.; te Riele, Gert Jan

    2017-11-01

    This paper presents a planar cooling strategy for advanced electronic applications using heat pipe technology. The principle idea is to use an array of relatively long heat pipes, whereby heat is disposed to a long section of the pipes. The proposed design uses 1 m long heat pipes and top cooling through a fan-based heat sink. Successful heat pipe operation and experimental performances are determined for seven heating configurations, considering active bottom, middle and top sections, and four orientation angles (0°, 30°, 60° and 90°). For all heating sections active, the heat pipe oriented vertically in an evaporator-down mode and a power input of 150 W, the overall thermal resistance was 0.014 K/W at a thermal gradient of 2.1 K and an average operating temperature of 50.7 °C. Vertical operation showed best results, as can be expected; horizontally the heat pipe could not be tested up to the power limit and dry-out occurred between 20 and 80 W depending on the heating configuration. Heating configurations without the bottom section active demonstrated a dynamic start-up effect, caused by heat conduction towards the liquid pool and thereafter batch-wise introducing the working fluid into the two-phase cycle. By analysing the heat pipe limitations for the intended operating conditions, a suitable heat pipe geometry was chosen. To predict the thermal performance a thermal model using a resistance network was created. The model compares well with the measurement data, especially for higher input powers. Finally, the thermal model is used for the design of a 1 kW planar system-level electronics cooling infrastructure featuring six 1 m heat pipes in parallel having a long ( 75%) evaporator section.

  13. Evaporation suppression from water reservoirs using floating covers: Lab scale observations and model predictions

    Science.gov (United States)

    Or, D.; Lehmann, P.; Aminzadeh, M.; Sommer, M.; Wey, H.; Wunderli, H.; Breitenstein, D.

    2016-12-01

    The competition over dwindling fresh water resources is expected to intensify with projected increase in human population in arid regions, expansion of irrigated land and changes in climate and drought patterns. The volume of water stored in reservoirs would also increase to mitigate seasonal shortages due to rainfall variability and to meet irrigation water needs. By some estimates up to half of the stored water is lost to evaporation thereby exacerbating the water scarcity problem. Recently, there is an upsurge in the use of self-assembling floating covers to suppress evaporation, yet the design, and implementation remain largely empirical. Studies have shown that evaporation suppression is highly nonlinear, as also known from a century of research on gas exchange from plant leaves (that often evaporate as free water surfaces through stomata that are only 1% of leaf area). We report a systematic evaluation of different cover types and external drivers (radiation, wind, wind+radiation) on evaporation suppression and energy balance of a 1.4 m2 basin placed in a wind-tunnel. Surprisingly, evaporation suppression by black and white floating covers (balls and plates) were similar despite significantly different energy balance regimes over the cover surfaces. Moreover, the evaporation suppression efficiency was a simple function of the uncovered area (square root of the uncovered fraction) with linear relations with the covered area in some cases. The thermally decoupled floating covers offer an efficient solution to the evaporation suppression with limited influence of the surface energy balance (water temperature for black and white covers was similar and remained nearly constant). The results will be linked with a predictive evaporation-energy balance model and issues of spatial scales and long exposure times will be studied.

  14. Effects of Surface Dipole Lengths on Evaporation of Tiny Water Aggregation

    International Nuclear Information System (INIS)

    Wang Shen; Wan Rongzheng; Fang Haiping; Tu Yusong

    2013-01-01

    Using molecular dynamics simulation, we compared evaporation behavior of a tiny amount of water molecules adsorbed on solid surfaces with different dipole lengths, including surface dipole lengths of 1 fold, 2 folds, 4 folds, 6 folds and 8 folds of 0.14 nm and different charges from 0.1e to 0.9e. Surfaces with short dipole lengths (1-fold system) can always maintain hydrophobic character and the evaporation speeds are not influenced, whether the surface charges are enhanced or weakened; but when surface dipole lengths get to 8 folds, surfaces become more hydrophilic as the surface charge increases, and the evaporation speeds increase gradually and monotonically. By tuning dipole lengths from 1-fold to 8-fold systems, we confirmed non-monotonic variation of the evaporation flux (first increases, then decreases) in 4 fold system with charges (0.1e–0.7e), reported in our previous paper [S. Wang, et al., J. Phys. Chem. B 116 (2012) 13863], and also show the process from the enhancement of this unexpected non-monotonic variation to its vanishment with surface dipole lengths increasing. Herein, we demonstrated two key factors to influence the evaporation flux of a tiny amount of water molecules adsorbed on solid surfaces: the exposed surficial area of water aggregation from where the water molecules can evaporate directly and the attraction potential from the substrate hindering the evaporation. In addition, more interestingly, we showed extra steric effect of surface dipoles on further increase of evaporation flux for 2-folds, 4-folds, 6-folds and 8-folds systems with charges around larger than 0.7e. (The steric effect is first reported by parts of our authors [C. Wang, et al., Sci. Rep. 2 (2012) 358]). This study presents a complete physical picture of the influence of surface dipole lengths on the evaporation behavior of the adsorbed tiny amount of water. (condensed matter: structural, mechanical, and thermal properties)

  15. Water evaporation on highly viscoelastic polymer surfaces.

    Science.gov (United States)

    Pu, Gang; Severtson, Steven J

    2012-07-03

    Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film.

  16. Controlling water evaporation through self-assembly.

    Science.gov (United States)

    Roger, Kevin; Liebi, Marianne; Heimdal, Jimmy; Pham, Quoc Dat; Sparr, Emma

    2016-09-13

    Water evaporation concerns all land-living organisms, as ambient air is dryer than their corresponding equilibrium humidity. Contrarily to plants, mammals are covered with a skin that not only hinders evaporation but also maintains its rate at a nearly constant value, independently of air humidity. Here, we show that simple amphiphiles/water systems reproduce this behavior, which suggests a common underlying mechanism originating from responding self-assembly structures. The composition and structure gradients arising from the evaporation process were characterized using optical microscopy, infrared microscopy, and small-angle X-ray scattering. We observed a thin and dry outer phase that responds to changes in air humidity by increasing its thickness as the air becomes dryer, which decreases its permeability to water, thus counterbalancing the increase in the evaporation driving force. This thin and dry outer phase therefore shields the systems from humidity variations. Such a feedback loop achieves a homeostatic regulation of water evaporation.

  17. Modelling refrigerant distribution in microchannel evaporators

    DEFF Research Database (Denmark)

    Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

    2009-01-01

    of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...... out of the evaporator is kept constant. It is shown that the cooling capacity of the evaporator is reduced significantly, both in the case of unevenly distributed inlet quality and for the case of non-uniform airflow on the outside of the channels.......The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...

  18. Sodium evaporation into a forced argon flow

    International Nuclear Information System (INIS)

    Kumada, Toshiaki; Kasahara, Fumio; Ishiguro, Ryoji

    1975-01-01

    Evaporation from a rectangular sodium free surface into an argon flow was measured. Tests were carried out with varying sodium temperature, argon velocity and argon temperature respectively under conditions of fog formation being possible. In order to clarify the enhancement of evaporation by fog formation, convection heat transfer from a plate of the same geometry into an air flow was also measured. The evaporation rate and Sherwood number were compared with those predicted by both the heat transfer experiment and the theory proposed by Hill and Szekely, and also a comparison was run with the previously reported experimental results of sodium evaporation. As a result it was shown that the sodium evaporation rate in this experiment is at least four times as large as that predicted by the heat transfer experiment and varies almost linearly with the heat transfer rate and the sodium vapour pressure. (auth.)

  19. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

    Science.gov (United States)

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  20. Optical properties on thermally evaporated and heat-treated ...

    Indian Academy of Sciences (India)

    Administrator

    of the intra-molecular bonds between the powder compounds and thin films. The optical ... Keywords. Phthalocyanine; thin films; optical properties; absorption spectra. 1. .... Leica Cambridge scanning electron microscope (model. Stereoscan ...

  1. Electrical properties of thermally evaporated nickel-dimethylglyoxime thin films

    Science.gov (United States)

    Dakhel, A. A.; Ali-Mohamed Ahmed, Y.

    2005-06-01

    Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)2] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)2/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ac conductance, from which the surface states density Dit of insulator/semiconductor interface and the density of the fixed charges in the oxide were determined. The ac electrical conduction and dielectric properties of the Ni(DMG)2-Silicon structure were studied at room temperature. The data of the ac measurements of the annealed films follow the correlated barrier-hopping CBH mode, from which the fundamental absorption bandgap, the minimum hopping distance, and other parameters of the model were determined.

  2. Evaporational losses under different soil moisture regimes and atmospheric evaporativities using tritium

    International Nuclear Information System (INIS)

    Saxena, P.; Chaudhary, T.N.; Mookerji, P.

    1991-01-01

    Tritium as tracer was used in a laboratory study to estimate the contribution of moisture from different soil depths towards actual soil water evaporation. Results indicated that for comparable amounts of free water evaporation (5 cm), contribution of moisture from 70-80 cm soil layer towards total soil moisture loss through evaporation increased nearly 1.5 to 3 folds for soils with water table at 90 cm than without water table. Identical initial soil moistures were exposed to different atmospheric evaporativities. Similarly, for a given initial soil moisture status, upward movement of moisture from 70-80 cm soil layer under low evaporativity was nearly 8 to 12 times that of under high evaporativity at 5 cm free water evaporation value. (author). 6 refs., 4 tabs., 2 figs

  3. Computer-Aided Modelling of Short-Path Evaporation for Chemical Product Purification, Analysis and Design

    DEFF Research Database (Denmark)

    Sales-Cruz, Alfonso Mauricio; Gani, Rafiqul

    2006-01-01

    method, suitable for separation and purification of thermally unstable materials whose design and analysis can be efficiently performed through reliable model-based techniques. This paper presents a generalized model for short-path evaporation and highlights its development, implementation and solution...

  4. Apparatus for diffusion-gap thermal desalination

    Science.gov (United States)

    Lowenstein, Andrew

    2017-09-26

    A thermal distillation apparatus including evaporation surfaces that are wetted with a solution, and from which at least some of the volatile solvent contained in the solution evaporates, condensers having an external surface in close proximity to, but not touching, a corresponding one of the one or more evaporation surfaces, and on which vapors of the solvent condense, releasing thermal energy that heats a flow of the solution moving upward within the condensers, spacers that prevent contact between the evaporating surfaces and the condensers, wherein spaces between the evaporating surfaces and the condensers are filled with a gaseous mixture composed of solvent vapor and one or more non-condensable gases, and except for diffusion of the solvent vapor relative to the non-condensable gases, the gaseous mixture is stationary.

  5. The evaporation of the charged and uncharged water drops

    Indian Academy of Sciences (India)

    Drop evaporation; ventilation coefficient; evaporation-effect of electrical forces. ... to study the effect of ventilation on the rate of evaporation of the millimeter sized ... a ventilated drop to reach its equilibrium temperature increases with the drop ...

  6. 242-A evaporator safety analysis report

    International Nuclear Information System (INIS)

    CAMPBELL, T.A.

    1999-01-01

    This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR

  7. 242-A evaporator safety analysis report

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL, T.A.

    1999-05-17

    This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR.

  8. Evaporation of freely suspended single droplets: experimental, theoretical and computational simulations

    International Nuclear Information System (INIS)

    Hołyst, R; Litniewski, M; Jakubczyk, D; Kolwas, K; Kolwas, M; Kowalski, K; Migacz, S; Palesa, S; Zientara, M

    2013-01-01

    Evaporation is ubiquitous in nature. This process influences the climate, the formation of clouds, transpiration in plants, the survival of arctic organisms, the efficiency of car engines, the structure of dried materials and many other phenomena. Recent experiments discovered two novel mechanisms accompanying evaporation: temperature discontinuity at the liquid–vapour interface during evaporation and equilibration of pressures in the whole system during evaporation. None of these effects has been predicted previously by existing theories despite the fact that after 130 years of investigation the theory of evaporation was believed to be mature. These two effects call for reanalysis of existing experimental data and such is the goal of this review. In this article we analyse the experimental and the computational simulation data on the droplet evaporation of several different systems: water into its own vapour, water into the air, diethylene glycol into nitrogen and argon into its own vapour. We show that the temperature discontinuity at the liquid–vapour interface discovered by Fang and Ward (1999 Phys. Rev. E 59 417–28) is a rule rather than an exception. We show in computer simulations for a single-component system (argon) that this discontinuity is due to the constraint of momentum/pressure equilibrium during evaporation. For high vapour pressure the temperature is continuous across the liquid–vapour interface, while for small vapour pressures the temperature is discontinuous. The temperature jump at the interface is inversely proportional to the vapour density close to the interface. We have also found that all analysed data are described by the following equation: da/dt = P 1 /(a + P 2 ), where a is the radius of the evaporating droplet, t is time and P 1 and P 2 are two parameters. P 1 = −λΔT/(q eff ρ L ), where λ is the thermal conductivity coefficient in the vapour at the interface, ΔT is the temperature difference between the liquid droplet

  9. Theory of evapotranspiration. 2. Soil and intercepted water evaporation

    OpenAIRE

    Budagovskyi, Anatolij Ivanovič; Novák, Viliam

    2011-01-01

    Evaporation of water from the soil is described and quantified. Formation of the soil dry surface layer is quantitatively described, as a process resulting from the difference between the evaporation and upward soil water flux to the soil evaporating level. The results of evaporation analysis are generalized even for the case of water evaporation from the soil under canopy and interaction between evaporation rate and canopy transpiration is accounted for. Relationships describing evapotranspi...

  10. Low-temperature field evaporation of Nb3Sn compound

    International Nuclear Information System (INIS)

    Ksenofontov, V.A.; Kul'ko, V.B.; Kutsenko, P.A.

    1986-01-01

    Investigation results on field evaporation of superconducting Nb 3 Sn compound wth A15 lattice are presented. Compound evaporation is shown to proceed in two stages. Evaporation field and ionic composition of evaporating material are determined. It is found out that in strong electric fields compound surface represents niobium skeleton, wich does not form regular image. Comparison of ion-microscopic and calculated images formed by low-temperature field evaporation indicates to possibility of sample surface reconstruction after preferable tin evaporation

  11. Enhanced Evaporation and Condensation in Tubes

    Science.gov (United States)

    Honda, Hiroshi

    A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

  12. WTP Pilot-Scale Evaporation Tests

    International Nuclear Information System (INIS)

    QURESHI, ZAFAR

    2004-01-01

    This report documents the design, assembly, and operation of a Pilot-Scale Evaporator built and operated by SRTC in support of Waste Treatment Plant (WTP) Project at the DOE's Hanford Site. The WTP employs three identical evaporators, two for the Waste Feed and one for the Treated LAW. The Pilot-Scale Evaporator was designed to test simulants for both of these waste streams. The Pilot-Scale Evaporator is 1/76th scale in terms of evaporation rates. The basic configuration of forced circulation vacuum evaporator was employed. A detailed scaling analysis was performed to preserve key operating parameters such as basic loop configuration, system vacuum, boiling temperature, recirculation rates, vertical distances between important hardware pieces, reboiler heat transfer characteristics, vapor flux, configuration of demisters and water spray rings. Three evaporation test campaigns were completed. The first evaporation run used water in order to shake down the system. The water runs were important in identifying a design flaw that inhibited mixing in the evaporator vessel, thus resulting in unstable boiling operation. As a result the loop configuration was modified and the remaining runs were completed successfully. Two simulant runs followed the water runs. Test 1: Simulated Ultrafiltration Recycles with HLW SBS, and Test 2: Treated AN102 with Envelop C LAW. Several liquid and offgas samples were drawn from the evaporator facility for regulatory and non-regulatory analyses. During Test 2, the feed and the concentrate were spiked with organics to determine organic partitioning. The decontamination factor (DF) for Test 1 was measured to be 110,000 (more than the expected value of 100,000). Dow Corning Q2-3183A antifoam agent was tested during both Tests 1 and 2. It was determined that 500 ppm of this antifoam agent was sufficient to control the foaminess to less than 5 per cent of the liquid height. The long-term testing (around 100 hours of operation) did not show any

  13. Towards a rational definition of potential evaporation

    Directory of Open Access Journals (Sweden)

    J.-P. Lhommel

    1997-01-01

    Full Text Available The concept of potential evaporation is defined on the basis of the following criteria: (i it must establish an upper limit to the evaporation process in a given environment (the term 'environment' including meteorological and surface conditions, and (ii this upper limit must be readily calculated from measured input data. It is shown that this upper limit is perfectly defined and is given by the Penman equation, applied with the corresponding meteorological data (incoming radiation and air characteristics measured at a reference height and the appropriate surface characteristics (albedo, roughness length, soil heat flux. Since each surface has its own potential evaporation, a function of its own surface characteristics, it is useful to define a reference potential evaporation as a short green grass completely shading the ground. Although the potential evaporation from a given surface is readily calculated from the Penman equation, its physical significance or interpretation is not so straightforward, because it represents only an idealized situation, not a real one. Potential evaporation is the evaporation from this surface, when saturated and extensive enough to obviate any effect of local advection, under the same meteorological conditions. Due to the feedback effects of evaporation on air characteristics, it does not represent the 'real' evaporation (i.e. the evaporation which could be physically observed in the real world from such an extensive saturated surface in these given meteorological conditions (if this saturated surface were substituted for an unsaturated one previously existing. From a rigorous standpoint, this calculated potential evaporation is not physically observable. Nevertheless, an approximate representation can be given by the evaporation from a limited saturated area, the dimension of which depends on the height of measurement of the air characteristics used as input in the Penman equation. If they are taken at a height

  14. Experimental investigation of a novel configuration of desiccant based evaporative air conditioning system

    International Nuclear Information System (INIS)

    Uçkan, İrfan; Yılmaz, Tuncay; Hürdoğan, Ertaç; Büyükalaca, Orhan

    2013-01-01

    Highlights: ► A novel desiccant based evaporative cooling system is developed and tested. ► Cooling capacity, COP and energy consumption of the system are evaluated. ► Indoor air conditions are in the range of thermal comfort zone and expanded comfort zone. ► Designing of the system have considerable effect on the energy consumption. - Abstract: A novel configuration of desiccant based evaporative cooling system for air conditioning application is developed and tested. At the beginning of the design stage of the system, an analysis is carried out in order to maximize the performance of the system. It is found based on configuration that outdoor air must be used for regeneration to increase performance of the system and so three air channels are used. Experiments are carried out to investigate the total performance of the system and performance of the components used during summer season in a hot and humid climate. Effectiveness values for both heat exchangers and evaporative coolers are calculated through this work. In addition to the cooling capacity, coefficient of performance (COP) and energy consumption of the system are also evaluated. Results show that the effectiveness for the heat exchangers and evaporative coolers are very high under different outdoor conditions. It is also shown from the results that indoor air conditions are in the range of thermal comfort zone defined by ASHRAE and expanded comfort zone for evaporative air conditioning applications.

  15. New approaches to the modelling of multi-component fuel droplet heating and evaporation

    KAUST Repository

    Sazhin, Sergei S

    2015-02-25

    The previously suggested quasi-discrete model for heating and evaporation of complex multi-component hydrocarbon fuel droplets is described. The dependence of density, viscosity, heat capacity and thermal conductivity of liquid components on carbon numbers n and temperatures is taken into account. The effects of temperature gradient and quasi-component diffusion inside droplets are taken into account. The analysis is based on the Effective Thermal Conductivity/Effective Diffusivity (ETC/ED) model. This model is applied to the analysis of Diesel and gasoline fuel droplet heating and evaporation. The components with relatively close n are replaced by quasi-components with properties calculated as average properties of the a priori defined groups of actual components. Thus the analysis of the heating and evaporation of droplets consisting of many components is replaced with the analysis of the heating and evaporation of droplets consisting of relatively few quasi-components. It is demonstrated that for Diesel and gasoline fuel droplets the predictions of the model based on five quasi-components are almost indistinguishable from the predictions of the model based on twenty quasi-components for Diesel fuel droplets and are very close to the predictions of the model based on thirteen quasi-components for gasoline fuel droplets. It is recommended that in the cases of both Diesel and gasoline spray combustion modelling, the analysis of droplet heating and evaporation is based on as little as five quasi-components.

  16. Use of Artificial Neural Networks for Prediction of Convective Heat Transfer in Evaporative Units

    Directory of Open Access Journals (Sweden)

    Romero-Méndez Ricardo

    2014-01-01

    Full Text Available Convective heat transfer prediction of evaporative processes is more complicated than the heat transfer prediction of single-phase convective processes. This is due to the fact that physical phenomena involved in evaporative processes are very complex and vary with the vapor quality that increases gradually as more fluid is evaporated. Power-law correlations used for prediction of evaporative convection have proved little accuracy when used in practical cases. In this investigation, neural-network-based models have been used as a tool for prediction of the thermal performance of evaporative units. For this purpose, experimental data were obtained in a facility that includes a counter-flow concentric pipes heat exchanger with R134a refrigerant flowing inside the circular section and temperature controlled warm water moving through the annular section. This work also included the construction of an inverse Rankine refrigeration cycle that was equipped with measurement devices, sensors and a data acquisition system to collect the experimental measurements under different operating conditions. Part of the data were used to train several neural-network configurations. The best neural-network model was then used for prediction purposes and the results obtained were compared with experimental data not used for training purposes. The results obtained in this investigation reveal the convenience of using artificial neural networks as accurate predictive tools for determining convective heat transfer rates of evaporative processes.

  17. Towards efficient next generation light sources: combined solution processed and evaporated layers for OLEDs

    Science.gov (United States)

    Hartmann, D.; Sarfert, W.; Meier, S.; Bolink, H.; García Santamaría, S.; Wecker, J.

    2010-05-01

    Typically high efficient OLED device structures are based on a multitude of stacked thin organic layers prepared by thermal evaporation. For lighting applications these efficient device stacks have to be up-scaled to large areas which is clearly challenging in terms of high through-put processing at low-cost. One promising approach to meet cost-efficiency, high through-put and high light output is the combination of solution and evaporation processing. Moreover, the objective is to substitute as many thermally evaporated layers as possible by solution processing without sacrificing the device performance. Hence, starting from the anode side, evaporated layers of an efficient white light emitting OLED stack are stepwise replaced by solution processable polymer and small molecule layers. In doing so different solutionprocessable hole injection layers (= polymer HILs) are integrated into small molecule devices and evaluated with regard to their electro-optical performance as well as to their planarizing properties, meaning the ability to cover ITO spikes, defects and dust particles. Thereby two approaches are followed whereas in case of the "single HIL" approach only one polymer HIL is coated and in case of the "combined HIL" concept the coated polymer HIL is combined with a thin evaporated HIL. These HIL architectures are studied in unipolar as well as bipolar devices. As a result the combined HIL approach facilitates a better control over the hole current, an improved device stability as well as an improved current and power efficiency compared to a single HIL as well as pure small molecule based OLED stacks. Furthermore, emitting layers based on guest/host small molecules are fabricated from solution and integrated into a white hybrid stack (WHS). Up to three evaporated layers were successfully replaced by solution-processing showing comparable white light emission spectra like an evaporated small molecule reference stack and lifetime values of several 100 h.

  18. Measurements of evaporation from a mine void lake and testing of modelling approaches

    Science.gov (United States)

    McJannet, David; Hawdon, Aaron; Van Niel, Tom; Boadle, Dave; Baker, Brett; Trefry, Mike; Rea, Iain

    2017-12-01

    Pit lakes often form in the void that remains after open cut mining operations cease. As pit lakes fill, hydrological and geochemical processes interact and these need to be understood for appropriate management actions to be implemented. Evaporation is important in the evolution of pit lakes as it acts to concentrate various constituents, controls water level and changes the thermal characteristics of the water body. Despite its importance, evaporation from pit lakes is poorly understood. To address this, we used an automated floating evaporation pan and undertook measurements at a pit lake over a 12 month period. We also developed a new procedure for correcting floating pan evaporation estimates to lake evaporation estimates based on surface temperature differences. Total annual evaporation was 2690 mm and reflected the strong radiation inputs, high temperatures and low humidity experienced in this region. Measurements were used to test the performance of evaporation estimates derived using both pan coefficient and aerodynamic modelling techniques. Daily and monthly evaporation estimates were poorly reproduced using pan coefficient techniques and their use is not recommended for such environments. Aerodynamic modelling was undertaken using a range of input datasets that may be available to those who manage pit lake systems. Excellent model performance was achieved using over-water or local over-land meteorological observations, particularly when the sheltering effects of the pit were considered. Model performance was reduced when off-site data were utilised and differences between local and off-site vapor pressure and wind speed were found to be the major cause.

  19. Experimental and numerical study of an evaporatively-cooled condenser of air-conditioning systems

    International Nuclear Information System (INIS)

    Islam, M.R.; Jahangeer, K.A.; Chua, K.J.

    2015-01-01

    The performance of an air-conditioning unit with evaporately-cooled condenser coil is studied experimentally and numerically. An experimental setup is fabricated by retrofitting a commercially available air-conditioning unit and installing comprehensive measuring sensors and controllers. Experimental result shows that the COP (Coefficient of Performance) of the evaporately-cooled air-conditioning unit increases by about 28% compared to the conventional air cooled air-conditioning unit. To analyze the heat and mass transfer processes involved in the evaporately-cooled condenser, a detailed theoretical model has been developed based on the fluid flow characteristics of the falling film and the thermodynamic aspect of the evaporation process. Simulated results agree well with experimental data. The numerical model provides new insights into the intrinsic links between operating variables and heat transfer characteristics of water film in evaluating the performance of evaporatively-cooled condenser system. Two heat transfer coefficients, namely, wall to bulk and bulk to interface are introduced and computed from the simulation results under different operating conditions. Finally, the overall heat transfer coefficient for the water film is computed and presented as a function of dimensionless variables which can conveniently be employed by engineers to design and analyze high performance evaporatively-cooled heat exchangers. - Highlights: • Performance of evaporatively-cooled condenser is investigated. • Local convective heat transfer coefficients of water film are determined. • Thermal resistance of water film is negligible. • Heat transfer with evaporated vapor plays significant role on performance. • Better condenser performance translates to an improvement in COP

  20. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    Science.gov (United States)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  1. Triple-line behavior and wettability controlled by nanocoated substrates: influence on sessile drop evaporation.

    Science.gov (United States)

    Sobac, B; Brutin, D

    2011-12-20

    In this article, we investigate the influence of the surface properties of substrates on the evaporation process. Using various nanocoatings, it is possible to modify the surface properties of substrates, such as the roughness and the surface energy, while maintaining constant thermal properties. Experiments are conducted under atmospheric conditions with five fluids (methanol, ethanol, propanol, toluene and water) and four coatings (PFC, PTFE, SiOC, and SiO(x)). The various combinations of these fluids and coatings allow for a wide range of drop evaporation properties to be studied: the dynamics of the triple line, the volatility of fluids, and a large range of wettabilities (from 17 to 135°). The experimental data are in very good quantitative agreement with existing models of quasi-steady, diffusion-driven evaporation. The experimental results show that the dynamics of the evaporative rate are proportional to the dynamics of the wetting radius. Thus, the models succeed in describing the evaporative dynamics throughout the evaporation process regardless of the behavior of the triple line. Moreover, the use of various liquids reveals the validity of the models regardless of their volatility. The results also confirm the recent finding of a universal relation for the time evolution of the drop mass, independent of the drop size and initial contact angle. Finally, this study highlights the separate and coupled roles of the triple line and the wettability on the sessile drop evaporation process. Data reveal that the more wet and pinned a drop, the shorter the evaporation time. © 2011 American Chemical Society

  2. Influence of instrument conditions on the evaporation behavior of uranium dioxide with UV laser-assisted atom probe tomography

    International Nuclear Information System (INIS)

    2015-01-01

    Atom probe tomography (APT) provides the ability to detect subnanometer chemical variations spatially with high accuracy. Due to its ability to spatially characterize chemistry in non-conducting materials, such as oxides, provides the opportunity to characterize stoichiometry, which strongly is tied to material performance. However, accuracy has been correlated with instrument run parameters. A systematic study of the effect of laser energy, temperature, and detection rate is performed on the evaporation behavior of a model oxide, uranium dioxide (UO 2 ). Modifying the detection rate and temperature did not affect its evaporation behavior as laser energy. It was discovered that three laser evaporation regimes are present in UO 2 . Very low laser energy produces a behavior similar to DC-field evaporation, moderate laser energy produces the desired laser assisted field evaporation and high laser energy produces thermal effects in the evaporation behavior. Laser energy had the greatest impact on evaporation and the optimal instrument condition for UO 2 was determined to be 50K, 10 pJ laser energy, 0.3% detection rate, and a 100 kHz repetition rate. These conditions provide the best combination of mass resolution, accurate stoichiometry, and evaporation behavior.

  3. Transhorizon Radiowave Propagation due to Evaporation Dueting

    Indian Academy of Sciences (India)

    from the meteorological perspective, evaporation ducts have far reaching implications on radio communications ... Background Theory ... It is in this context that the tropo- .... eters that are representative of the ongoing physical processes at.

  4. Influence of Evaporation on Soap Film Rupture.

    Science.gov (United States)

    Champougny, Lorène; Miguet, Jonas; Henaff, Robin; Restagno, Frédéric; Boulogne, François; Rio, Emmanuelle

    2018-03-13

    Although soap films are prone to evaporate due to their large surface to volume ratio, the effect of evaporation on macroscopic film features has often been disregarded in the literature. In this work, we experimentally investigate the influence of environmental humidity on soap film stability. An original experiment allows to measure both the maximum length of a film pulled at constant velocity and its thinning dynamics in a controlled atmosphere for various values of the relative humidity [Formula: see text]. At first order, the environmental humidity seems to have almost no impact on most of the film thinning dynamics. However, we find that the film length at rupture increases continuously with [Formula: see text]. To rationalize our observations, we propose that film bursting occurs when the thinning due to evaporation becomes comparable to the thinning due to liquid drainage. This rupture criterion turns out to be in reasonable agreement with an estimation of the evaporation rate in our experiment.

  5. Evaporation analysis for Tank SX-104

    International Nuclear Information System (INIS)

    Barrington, C.A.

    1994-10-01

    Decreases in historical interstitial liquid level measurements in tank SX-104 were compared to predictions of a numerical model based upon diffusion of water through a porous crust. The analysis showed that observed level decreases could be explained by evaporation

  6. Denton E-beam Evaporator #2

    Data.gov (United States)

    Federal Laboratory Consortium — Description:CORAL Name: E-Beam Evap 2This is an electron gun evaporator for the deposition of metals and dielectrics thin films. Materials available are: Ag, Al, Au,...

  7. Fabrication of Josephson Junction without shadow evaporation

    Science.gov (United States)

    Wu, Xian; Ku, Hsiangsheng; Long, Junling; Pappas, David

    We developed a new method of fabricating Josephson Junction (Al/AlOX/Al) without shadow evaporation. Statistics from room temperature junction resistance and measurement of qubits are presented. Unlike the traditional ``Dolan Bridge'' technique, this method requires two individual lithographies and straight evaporations of Al. Argon RF plasma is used to remove native AlOX after the first evaporation, followed by oxidation and second Al evaporation. Junction resistance measured at room temperature shows linear dependence on Pox (oxidation pressure), √{tox} (oxidation time), and inverse proportional to junction area. We have seen 100% yield of qubits made with this method. This method is promising because it eliminates angle dependence during Junction fabrication, facilitates large scale qubits fabrication.

  8. Lattice-Boltzmann simulations of droplet evaporation

    KAUST Repository

    Ledesma-Aguilar, Rodrigo; Vella, Dominic; Yeomans, Julia M.

    2014-01-01

    © the Partner Organisations 2014. We study the utility and validity of lattice-Boltzmann (LB) simulations to explore droplet evaporation driven by a concentration gradient. Using a binary-fluid lattice-Boltzmann algorithm based on Cahn-Hilliard dynamics, we study the evaporation of planar films and 3D sessile droplets from smooth solid surfaces. Our results show that LB simulations accurately reproduce the classical regime of quasi-static dynamics. Beyond this limit, we show that the algorithm can be used to explore regimes where the evaporative and diffusive timescales are not widely separated, and to include the effect of boundaries of prescribed driving concentration. We illustrate the method by considering the evaporation of a droplet from a solid surface that is chemically patterned with hydrophilic and hydrophobic stripes. This journal is

  9. Lattice-Boltzmann simulations of droplet evaporation

    KAUST Repository

    Ledesma-Aguilar, Rodrigo

    2014-09-04

    © the Partner Organisations 2014. We study the utility and validity of lattice-Boltzmann (LB) simulations to explore droplet evaporation driven by a concentration gradient. Using a binary-fluid lattice-Boltzmann algorithm based on Cahn-Hilliard dynamics, we study the evaporation of planar films and 3D sessile droplets from smooth solid surfaces. Our results show that LB simulations accurately reproduce the classical regime of quasi-static dynamics. Beyond this limit, we show that the algorithm can be used to explore regimes where the evaporative and diffusive timescales are not widely separated, and to include the effect of boundaries of prescribed driving concentration. We illustrate the method by considering the evaporation of a droplet from a solid surface that is chemically patterned with hydrophilic and hydrophobic stripes. This journal is

  10. Evaporation of Lennard-Jones fluids.

    Science.gov (United States)

    Cheng, Shengfeng; Lechman, Jeremy B; Plimpton, Steven J; Grest, Gary S

    2011-06-14

    Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature T/T(c), where T(c) is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase.

  11. Rate control for electron gun evaporation

    International Nuclear Information System (INIS)

    Schellingerhout, A.J.G.; Janocko, M.A.; Klapwijk, T.M.; Mooij, J.E.

    1989-01-01

    Principles for obtaining high-quality rate control for electron gun evaporation are discussed. The design criteria for rate controllers are derived from this analysis. Results are presented which have been obtained with e-guns whose evaporation rate is controlled by a Wehnelt electrode or by sweeping of the electron beam. Further improvements of rate stability can be obtained by improved design of e-guns and power supplies

  12. Semiclassical Approach to Black Hole Evaporation

    OpenAIRE

    Lowe, David A.

    1992-01-01

    Black hole evaporation may lead to massive or massless remnants, or naked singularities. This paper investigates this process in the context of two quite different two dimensional black hole models. The first is the original CGHS model, the second is another two dimensional dilaton-gravity model, but with properties much closer to physics in the real, four dimensional, world. Numerical simulations are performed of the formation and subsequent evaporation of black holes and the results are fou...

  13. Towards a rational definition of potential evaporation

    OpenAIRE

    Lhomme, Jean-Paul

    1997-01-01

    International audience; The concept of potential evaporation is defined on the basis of the following criteria: (i) it must establish an upper limit to the evaporation process in a given environment (the term "environment" including meteorological and surface conditions), and (ii) this upper limit must be readily calculated from measured input data. It is shown that this upper limit is perfectly defined and is given by the Penman equation, applied with the corresponding meteorological data (i...

  14. The energy balance within a bubble column evaporator

    Science.gov (United States)

    Fan, Chao; Shahid, Muhammad; Pashley, Richard M.

    2018-05-01

    Bubble column evaporator (BCE) systems have been studied and developed for many applications, such as thermal desalination, sterilization, evaporative cooling and controlled precipitation. The heat supplied from warm/hot dry bubbles is to vaporize the water in various salt solutions until the solution temperature reaches steady state, which was derived into the energy balance of the BCE. The energy balance and utilization involved in each BCE process form the fundamental theory of these applications. More importantly, it opened a new field for the thermodynamics study in the form of heat and vapor transfer in the bubbles. In this paper, the originally derived energy balance was reviewed on the basis of its physics in the BCE process and compared with new proposed energy balance equations in terms of obtained the enthalpy of vaporization (Δ H vap) values of salt solutions from BCE experiments. Based on the analysis of derivation and Δ H vap values comparison, it is demonstrated that the original balance equation has high accuracy and precision, within 2% over 19-55 °C using improved systems. Also, the experimental and theoretical techniques used for determining Δ H vap values of salt solutions were reviewed for the operation conditions and their accuracies compared to the literature data. The BCE method, as one of the most simple and accurate techniques, offers a novel way to determine Δ H vap values of salt solutions based on its energy balance equation, which had error less than 3%. The thermal energy required to heat the inlet gas, the energy used for water evaporation in the BCE and the energy conserved from water vapor condensation were estimated in an overall energy balance analysis. The good agreement observed between input and potential vapor condensation energy illustrates the efficiency of the BCE system. Typical energy consumption levels for thermal desalination for producing pure water using the BCE process was also analyzed for different inlet air

  15. Accelerated evaporation of water on graphene oxide.

    Science.gov (United States)

    Wan, Rongzheng; Shi, Guosheng

    2017-03-29

    Using molecular dynamics simulations, we show that the evaporation of nanoscale volumes of water on patterned graphene oxide is faster than that on homogeneous graphene oxide. The evaporation rate of water is insensitive to variation in the oxidation degree of the oxidized regions, so long as the water film is only distributed on the oxidized regions. The evaporation rate drops when the water film spreads onto the unoxidized regions. Further analysis showed that varying the oxidation degree observably changed the interaction between the outmost water molecules and the solid surface, but the total interaction for the outmost water molecules only changed a very limited amount due to the correspondingly regulated water-water interaction when the water film is only distributed on the oxidized regions. When the oxidation degree is too low and some unoxidized regions are also covered by the water film, the thickness of the water film decreases, which extends the lifetime of the hydrogen bonds for the outmost water molecules and lowers the evaporation rate of the water. The insensitivity of water evaporation to the oxidation degree indicates that we only need to control the scale of the unoxidized and oxidized regions for graphene oxide to regulate the evaporation of nanoscale volumes of water.

  16. Estimating soil water evaporation using radar measurements

    Science.gov (United States)

    Sadeghi, Ali M.; Scott, H. D.; Waite, W. P.; Asrar, G.

    1988-01-01

    Field studies were conducted to evaluate the application of radar reflectivity as compared with the shortwave reflectivity (albedo) used in the Idso-Jackson equation for the estimation of daily evaporation under overcast sky and subhumid climatic conditions. Soil water content, water potential, shortwave and radar reflectivity, and soil and air temperatures were monitored during three soil drying cycles. The data from each cycle were used to calculate daily evaporation from the Idso-Jackson equation and from two other standard methods, the modified Penman and plane of zero-flux. All three methods resulted in similar estimates of evaporation under clear sky conditions; however, under overcast sky conditions, evaporation fluxes computed from the Idso-Jackson equation were consistently lower than the other two methods. The shortwave albedo values in the Idso-Jackson equation were then replaced with radar reflectivities and a new set of total daily evaporation fluxes were calculated. This resulted in a significant improvement in computed soil evaporation fluxes from the Idso-Jackson equation, and a better agreement between the three methods under overcast sky conditions.

  17. Treatment of liquid radioactive waste: Evaporation

    International Nuclear Information System (INIS)

    Pfeiffer, R.

    1982-01-01

    About 10.000 m 3 of low active liquid waste (LLW) arise in the Nuclear Research Center Karlsruhe. Chemical contents of this liquid waste are generally not declared. Resulting from experiments carried out in the Center during the early sixties, the evaporator facility was built in 1968 for decontamination of LLW. The evaporators use vapor compression and concentrate recirculation in the evaporator sump by pumps. Since 1971 the medium active liquid waste (MLW) from the Karlsruhe Reprocessing Plant (WAK) was decontaminated in this evaporator facility, too. By this time the amount of low liquid waste (LLW) had been decontaminated without mentionable interruptions. Afterwards a lot of interruptions of operations occurred, mainly due to leakages of pumps, valves and pipes. There was also a very high radiation level for the operating personnel. As a consequence of this experience a new evaporator facility for decontamination of medium active liquid waste was built in 1974. This facility started operation in 1976. The evaporator has natural circulation and is heated by steam through a heat exchanger. (orig./RW)

  18. Evaporation of petroleum products from contaminated soils

    International Nuclear Information System (INIS)

    Kang, S.H.

    1996-01-01

    Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions

  19. Water droplet evaporation from sticky superhydrophobic surfaces

    Science.gov (United States)

    Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

    2017-07-01

    The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

  20. Microdroplet evaporation in closed digital microfluidic biochips

    International Nuclear Information System (INIS)

    Ahmadi, Ali; Buat, Matthew D; Hoorfar, Mina

    2013-01-01

    In this paper, microdroplet evaporation in the closed digital microfluidic systems is studied for hydrophobic and hydrophilic surfaces. The contact angle and contact radius are measured by an enhanced automated polynomial fitting approach. It is observed that the contact angle for both hydrophobic and hydrophilic surfaces remains constant during the evaporation process. However, a higher evaporation rate is observed for hydrophilic droplets compared to the hydrophobic droplets. Since no contact line pinning is observed, first, an analytical model based on the uniform vapor mass flux along the liquid–vapor interface is proposed. Interestingly, it is observed that in the hydrophobic case, the analytical model gives a higher evaporation rate, whereas for the hydrophilic case, the analytical model gives a lower evaporation rate. The discrepancy between the results of the analytical modeling and the experimental values is hypothesized to be due the constant flux assumption. To verify the hypothesis, a finite volume-based numerical model is developed to find the local flux along the liquid–vapor interface. The numerical modeling results confirm that for hydrophilic droplets, the evaporation flux increases very close to the three-phase contact line. In the case of the hydrophobic droplets, on the other hand, the flux decreases close to the contact line due to vapor saturation; as a result the uniform flux assumption overestimates the mass loss. (paper)

  1. Snap evaporation of droplets on smooth topographies.

    Science.gov (United States)

    Wells, Gary G; Ruiz-Gutiérrez, Élfego; Le Lirzin, Youen; Nourry, Anthony; Orme, Bethany V; Pradas, Marc; Ledesma-Aguilar, Rodrigo

    2018-04-11

    Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a "stick-slip" sequence-a combination of pinning and de-pinning events dominated by static friction or "pinning", caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications.

  2. Exergoeconomic optimization of coaxial tube evaporators for cooling of high pressure gaseous hydrogen during vehicle fuelling

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Rothuizen, Erasmus Damgaard; Markussen, Wiebke Brix

    2014-01-01

    Gaseous hydrogen as an automotive fuel is reaching the point of commercial introduction. Development of hydrogen fuelling stations considering an acceptable fuelling time by cooling the hydrogen to -40 C has started. This paper presents a design study of coaxial tube ammonia evaporators for three......-stage evaporator. The main contribution to the total cost was the cost associated with exergy destruction, the capital investment cost contributed with 5-14 %. The main contribution to the exergy destruction was found to be thermally driven. The pressure driven exergy destruction accounted for 3-9 %....

  3. Experimental Measurements of the Water Evaporation Rate of a Physical Model

    Directory of Open Access Journals (Sweden)

    Turza Róbert

    2017-03-01

    Full Text Available As the number of indoor swimming pools and wellness centers are currently growing, it is necessary to concentrate on the parameters of indoor environments. These parameters are necessary for the design of the HVAC systems that operate these premises. In indoor swimming-pool facilities, the energy demand is large due to ventilation losses from exhaust air. Since water evaporates from a pool’s surface, exhaust air has a high water content and specific enthalpy. In this paper the results of the water evaporation rate measured from swimming pool surfaces at higher thermal water temperatures are described.

  4. Experimental Measurements of the Water Evaporation Rate of a Physical Model

    Science.gov (United States)

    Turza, Róbert; Füri, Belo B.

    2017-03-01

    As the number of indoor swimming pools and wellness centers are currently growing, it is necessary to concentrate on the parameters of indoor environments. These parameters are necessary for the design of the HVAC systems that operate these premises. In indoor swimming-pool facilities, the energy demand is large due to ventilation losses from exhaust air. Since water evaporates from a pool's surface, exhaust air has a high water content and specific enthalpy. In this paper the results of the water evaporation rate measured from swimming pool surfaces at higher thermal water temperatures are described.

  5. Numerical simulation of strong evaporation and condensation for plasma-facing materials

    International Nuclear Information System (INIS)

    Kunugi, T.; Yasuda, H.

    1994-01-01

    The thermal response of the divertor plate to the hard plasma disruptions had been analyzed numerically by the two dimensional transient heat transfer code. There are several studies of the vapor shielding effects on the thermal response to the plasma disruption. However, it was pointed out some discrepancies among the numerical results calculated by U.S., EC and Japan for the same disruption conditions by van der Laan. One of the authors studied the sensitivity of some parameters (i.e., the temperature dependency of the thermal properties, an evaporation coefficient and a saturated condensation ratio) of disruption erosion analysis. Though the authors expected that the variations in evaporation models lead to the large variety of the erosion, they gave no significant effects on the surface temperature, the evaporation and melt-layer thickness. In this paper, the authors will describe the development of the numerical simulation codes for the strong evaporation and condensation from the plasma facing materials (PFMs) such as carbon, tungsten and beryllium

  6. On the link between potential evaporation and regional evaporation from a CBL perspective

    Science.gov (United States)

    Lhomme, J. P.; Guilioni, L.

    2010-07-01

    The relationship between potential evaporation and actual evaporation was first examined by Bouchet (Proc Berkeley Calif Symp IAHS Publ, 62:134-142, 1963) who considered potential evaporation as the consequence of regional evaporation due to atmospheric feedbacks. Using a heuristic approach, he derived a complementary relationship which, despite no real theoretical background, has proven to be very useful in interpreting many experimental data under various climatic conditions. Here, the relationship between actual and potential evaporation is reinterpreted in the context of the development of the convective boundary layer (CBL): first, with a closed-box approach, where the CBL has an impermeable lid; and then with an open system, where air is exchanged between the CBL and its external environment. By applying steady forcing to these systems, it is shown that an equilibrium state is reached, where potential evaporation has a specific equilibrium formulation as a function of two parameters: one representing large-scale advection and the other the feedback effect of regional evaporation on potential evaporation, i.e. a kind of “medium-scale advection”. It is also shown that the original form of Bouchet’s complementary relationship is not verified in the equilibrium state. This analysis leads us to propose a new and more rational approach of the relationship between potential and actual evaporation through the effective surface resistance of the region.

  7. EVAPORATION FORM OF ICE CRYSTALS IN SUBSATURATED AIR AND THEIR EVAPORATION MECHANISM

    OpenAIRE

    ゴンダ, タケヒコ; セイ, タダノリ; Takehiko, GONDA; Tadanori, SEI

    1987-01-01

    The evaporation form and the evaporation mechanism of dendritic ice crystals grown in air of 1.0×(10)^5 Pa and at water saturation and polyhedral ice crystals grown in air of 4.0×10 Pa and at relatively low supersaturation are studied. In the case of dendritic ice crystals, the evaporation preferentially occurs in the convex parts of the crystal surfaces and in minute secondary branches. On the other hand, in the case of polyhedral ice crystals, the evaporation preferentially occurs in the pa...

  8. Convective instability of sludge storage under evaporation and solar radiation

    Science.gov (United States)

    Tsiberkin, Kirill; Tatyana, Lyubimova

    2014-05-01

    The sludge storages are an important part of production cycle at salt manufacturing, water supply, etc. A quality of water in the storage depends on mixing of pure water and settled sediment. One of the leading factors is thermal convection. There are two main mechanisms of the layer instability exist. First, it is instability of water due to evaporation from the free surface [1]. It cools the water from upside, increases the particles concentration and leads to the instability in the near-surface layer. Second, the sediment absorbs a solar radiation and heats the liquid from below making it unstable in the near-bottom area. We assume the initial state is the mechanical equilibrium. The water and sediment particles are motionless, the sediment forms a uniform sludge layer of thickness z0, there are no evaporation and heating by solar energy, and the temperature has a linear profile is determined by fixed upper and bottom temperatures of the layer. Taking into account the evaporation and solar radiation absorption, we obtain a non-stationary solution for the temperature using Fourier series method. The local temperature gradients increases rapidly with time, and local Rayleigh number can be estimated by thermal conduction length Lt: Raloc(z,t) = gβ(δT(z,t)/δz)L4t-/νΞ , Lt ~ √Ξt, (1) where g is gravity acceleration, β, ν and Ξ are thermal volume expansion coefficient, kinematic viscosity and thermal conductivity of the liquid, respectively. Raloc* reaches the critical value at finite time t* and water motion begins. The maximal power of solar radiation in visible band equals 230 Wt/m2 at the latitude of "Uralkalii" salt manufacturer (Berezniki, Perm Region, Russian Federation). We neglect IR and UV radiation because of its huge absorption by water [2]. The evaporation speed is found using results for shallow water reservoir [3] and meteorological data for Berezniki [4]. We get the t*~ 6 · 102 s (10 min) for the layer of 1 m depth and t*~ 2 · 103 s (40

  9. Simultaneous spreading and evaporation: recent developments.

    Science.gov (United States)

    Semenov, Sergey; Trybala, Anna; Rubio, Ramon G; Kovalchuk, Nina; Starov, Victor; Velarde, Manuel G

    2014-04-01

    The recent progress in theoretical and experimental studies of simultaneous spreading and evaporation of liquid droplets on solid substrates is discussed for pure liquids including nanodroplets, nanosuspensions of inorganic particles (nanofluids) and surfactant solutions. Evaporation of both complete wetting and partial wetting liquids into a nonsaturated vapour atmosphere are considered. However, the main attention is paid to the case of partial wetting when the hysteresis of static contact angle takes place. In the case of complete wetting the spreading/evaporation process proceeds in two stages. A theory was suggested for this case and a good agreement with available experimental data was achieved. In the case of partial wetting the spreading/evaporation of a sessile droplet of pure liquid goes through four subsequent stages: (i) the initial stage, spreading, is relatively short (1-2 min) and therefore evaporation can be neglected during this stage; during the initial stage the contact angle reaches the value of advancing contact angle and the radius of the droplet base reaches its maximum value, (ii) the first stage of evaporation is characterised by the constant value of the radius of the droplet base; the value of the contact angle during the first stage decreases from static advancing to static receding contact angle; (iii) during the second stage of evaporation the contact angle remains constant and equal to its receding value, while the radius of the droplet base decreases; and (iv) at the third stage of evaporation both the contact angle and the radius of the droplet base decrease until the drop completely disappears. It has been shown theoretically and confirmed experimentally that during the first and second stages of evaporation the volume of droplet to power 2/3 decreases linearly with time. The universal dependence of the contact angle during the first stage and of the radius of the droplet base during the second stage on the reduced time has been

  10. A comparison between evaporation ponds and evaporation surfaces as a source of the concentrated salt brine for salt gradient maintenance at Tajoura solar pond

    International Nuclear Information System (INIS)

    Ramadan, Abdulghani M.; Agha, Khairy R.; Abughres, M.

    2012-01-01

    One of the main problems that negatively affect the operation of salt gradient solar ponds and influence its thermal stability is the maintenance of salt gradient profile. Evaporation pond (EP) is designed to generate the salt which lost upward salt diffusion from the lower convective zone (LCZ) of the solar pond. Another attractive method is the evaporation surface facility (ES). Regions with moderate to high precipitation favor Evaporation Surface over Evaporation Ponds. Dry climates will generally favor Evaporation Ponds for the brine re-concentration. In previous studies [1-3], the authors have shown that the (EP) of Tajoura's Experimental Solar Pond (TESP) is under sized and can provide only about 30% of the salt required by a Salt Gradient Solar Pond (SGSP). The anticipated size of (EP) was estimated and presented in those studies under different design conditions, including Summer, Autumn and Spring designs, while the winter design was excluded due to the low rates of net evaporation during the winter season. In addition, the results presented were predicted for the first three years of operation. The daily variations of brine concentration in the (EP) of (TESP) and those based on different designs were predicted and discussed under different scenarios. The quantities of brine provided by the evaporation pond and that required by SGSP were predicted for both cases of surface water flushing (fresh water and sea-water) under the different design conditions as shown in Table 1. This paper investigates the differences between (EP) and (ES) both as a source for salt brine generation by evaporation. The effect of (EP) depth on the area ratio and daily variations of salt concentrations for three years of operation is shown. Results show that evaporation can be a reasonable method for salt brine generation. Reducing the depth of (EP) improves the capability of (EP) for brine re-concentration. It also increases the (EP) surface area for the same quantity of

  11. Evaporative water loss from welded tuff

    International Nuclear Information System (INIS)

    Hadley, G.R.; Turner, J.R. Jr.

    1980-04-01

    Welded tuff is one of the many candidate rocks presently being considered as a host medium for the disposal of radioactive waste. In the case where the disposal site lies above the water table, the host rock will in general be only partially saturated. This condition leads to a number of mass transfer processes of interest, including evaporative drying, two-phase water flow due to pressure gradients, capillary movement, plus others. Although these processes have all been known about for decades, it is not clear at this time what the relative importance of each is with regard to geologic media in a waste disposal environment. In particular, there seems to be no data available for tuff that would allow an investigator to sort out mechanisms. This work is intended to be a start in that direction. This paper reports the measurement of water loss rate for welded tuff at various temperatures due to the action of evaporative drying. The initial saturation was unknown, but the average initial water content was found to be 7% by weight. The resulting data show that the water loss rate declines monotonically with time at a given temperature and increases with increasing temperature as expected. Somewhat surprising, however, is the fact that over 90% of the water from a sample was lost by evaporation at room temperature within 72 hours. All the water loss data, including that taken at temperatures as high as 150 0 C, are explained to within a factor of two by a simple evaporation front model. The latter assumes the water is lost by the molecular diffusion of water vapor from a receding evaporation front. The motion of the evaporation front seems to depend on mass balance rather than energy balance. Capillary forces and the resulting liquid diffusion are evidently not strong enough to wash out the evaporation front, since the front model seems to fit the data well

  12. Heat enhancement of radiation resistivity of evaporated CsI, KI and KBr photocathodes

    CERN Document Server

    Tremsin, A S

    2000-01-01

    The photoemissive stability of as-deposited and heat-treated CsI, KI and KBr evaporated thin films under UV radiation is examined in this paper. After the deposition, some photocathodes were annealed for several hours at 90 deg. C in vacuum and their performance was then compared to the performance of non-heated samples. We observed that the post-evaporation thermal treatment not only increases the photoyield of CsI and KI photocathodes in the spectral range of 115-190 nm, but also reduces CsI, KI and KBr photocurrent degradation that occurs after UV irradiation. KBr evaporated layers appeared to be more radiation-resistant than CsI and KI layers. Post-deposition heat treatment did not result in any significant variation of KBr UV sensitivity.

  13. Estimating steady-state evaporation rates from bare soils under conditions of high water table

    Science.gov (United States)

    Ripple, C.D.; Rubin, J.; Van Hylckama, T. E. A.

    1970-01-01

    A procedure that combines meteorological and soil equations of water transfer makes it possible to estimate approximately the steady-state evaporation from bare soils under conditions of high water table. Field data required include soil-water retention curves, water table depth and a record of air temperature, air humidity and wind velocity at one elevation. The procedure takes into account the relevant atmospheric factors and the soil's capability to conduct 'water in liquid and vapor forms. It neglects the effects of thermal transfer (except in the vapor case) and of salt accumulation. Homogeneous as well as layered soils can be treated. Results obtained with the method demonstrate how the soil evaporation rates·depend on potential evaporation, water table depth, vapor transfer and certain soil parameters.

  14. Influence of evaporation conditions of Alq3 on the performance of organic light emitting diodes

    International Nuclear Information System (INIS)

    Zhang Fujun; Xu Zheng; Zhao Dewei; Zhao Suling; Jiang Weiwei; Yuan Guangcai; Song Dandan; Wang Yongsheng; Xu Xurong

    2007-01-01

    The influence of evaporation conditions of organic semiconductor material tris(8-hydroxyquinoline)aluminium (Alq 3 ) on the performance of organic light emitting diodes (OLEDs) is reported. In the process of organic material thermal evaporation, the chamber was dark or had white light from a 100 W filament lamp. The devices prepared in the dark show higher emission intensity and efficiency compared with the ones prepared in white light under the same driving voltage. Atomic force microscopy measurements show that surface morphology and phase of Alq 3 thin films are quite different for the previous cases. The different evaporation conditions are found to have direct effects on the electrical and luminance performance. The Alq 3 thin films prepared in the dark as active emission layers of OLEDs show higher intensity and efficiency

  15. Evaporation at microscopic scale and at high heat flux

    International Nuclear Information System (INIS)

    Janecek, V.

    2012-01-01

    This thesis theoretically investigates the transport processes in the vicinity of the triple gas-liquid-solid contact line and its impact on macroscopic evaporation. In the first part of the thesis, the hydrodynamics close to the contact line at partial wetting is studied. Specifically, evaporation into the atmosphere of pure vapor driven by heating of the substrate is considered. The question of singularity relaxation is addressed. The main finding of the thesis is that the Kelvin effect (dependence of saturation temperature on pressure) is sufficient by itself to relax the hydrodynamic contact line singularity. The proposed microregion (the contact line vicinity) model for small interface slopes is solved numerically. Asymptotic solutions are found for some specific cases. The governing length scales of the problem are identified and the multi-scale nature of the phenomenon is addressed. Parametric studies revealing the role of the thermal resistance of vapor-liquid interface, slip length, thermo-capillary term, the vapor recoil and surface forces are also performed. An extension of the lubrication approximation for high slopes of the gas-liquid interface at evaporation is discussed. In the second part of the thesis, the previously established microregion model is coupled to a simplified single vapor bubble growth numerical simulation. The bubble departure from the heater at boiling is also studied. It was proposed in the thesis, that under high heat loads, the increase of the apparent contact angle causes the vapor bubble to spread over the heated substrate. Such a behavior may cause the heater dry-out that occurs during the boiling crisis. (author) [fr

  16. Evaporation equipment with electron beam heating for the evaporation of metals and other conducting materials

    International Nuclear Information System (INIS)

    Mueller, P.

    1977-01-01

    Equipment for the evaporation of metals and other conducting materials by electron beam heating is to be improved by surrou nding the evaporation equipment with a grid, which has a negative voltage compared to the cathode. This achieves the state where the cathode is hit and damaged less by the ions formed, so that its life period is prolonged. (UWI) [de

  17. Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo droplet

    NARCIS (Netherlands)

    Tan, H.; Diddens, C.; Lv, P.; Kuerten, J.G.M.; Zhang, X.; Lohse, D.

    2016-01-01

    Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even

  18. Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop

    NARCIS (Netherlands)

    Tan, Huanshu; Diddens, Christian; Lv, Pengyu; Kuerten, J.G.M.; Zhang, Xuehua; Lohse, Detlef

    2016-01-01

    Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even

  19. Putting evaporators to work: wiped film evaporator for high level wastes

    International Nuclear Information System (INIS)

    Dierks, R.D.; Bonner, W.F.

    1976-01-01

    At Battelle, Pacific Northwest Laboratories, a pilot scale, wiped film evaporator was tested for concentrating high level liquid wastes from Purex-type nuclear fuel recovery processes. The concentrates produced up to 60 wt-percent total solids; and the simplicity of operation and design of the evaporator gave promise for low maintenance and high reliability

  20. Influence of heat consumers distribution and flashing vapours effect on steam consumption of evaporation plant of sugar factory

    Directory of Open Access Journals (Sweden)

    A. A. Gromkovskii

    2016-01-01

    Full Text Available The article considered the influence of the heat consumers distribution and the flashing vapours effect juice for multipleevaporator sugar factory on the consumption the main production flow of heat transfer agent – water vapor. The problem of rational distribution of heat transfer agent for of the corps multiple-evaporator is relevant from point of view of energy saving and energysaving heat of the sugar factory. The solution to this problem is advantageously carried out on the basis of quantitative mathematical description of the distribution of vapor on the corps of the evaporation plant. The heat consumers distribution should be based on technical and economic calculation. To solve this problem it is advisable to use a single equation that determines the dependence of the steam flow in the first unit evaporator on the amount of evaporated water and the method of heat consumers distribution for housing. Evaporators sugar factory has two functions – technology and heat, each of which is described by its equation. On the basis of the material and heat balance equations for the realization of the basic functions of the system evaporator written multipleevaporator equations. The solution of this system allows you to obtain the equation of the steam flow and the amount of evaporated water, taking into account the flashing vapours effect. Solution of the system should take into account the accepted design standards of sugar factories. As a result of solving the system of equation is obtained, which allows you to organize and optimize the heat consumers distribution of the corps evaporator. The equation can be used for any number of units evaporator. This equation allows you to assess the efficiency of the evaporation plant of a sugar factory. This is of great practical importance in the modernization of thermal schemes of sugar factories.

  1. Artificial weathering of oils by rotary evaporator

    International Nuclear Information System (INIS)

    Fieldhouse, B.; Hollebone, B.P.; Singh, N.R.; Tong, T.S.; Mullin, J.

    2009-01-01

    Oil weathering has a considerable affect on the behaviour, impact and ultimate fate of an oil spill. As such, efforts have been made to study weathering as a whole using bench-scale procedures. The studies are generally divided into individual processes where the effect of other major processes are introduce as an amended sample input rather than a concurrent process. The weathering process that has the greatest effect immediately following an oil spill is evaporation, particularly for lighter oils. The rotary evaporator apparatus offers a convenient means of producing artificially weathered oil for laboratory studies. This paper reported on a study that examined the representativeness of samples obtained by this method compared to pan evaporation and the impact of changes to the apparatus or method parameters on sample chemistry. Experiments were performed on Alberta Sweet Mixed Blend no. 5 in a rotary evaporator under varying conditions of temperature and air flow at ambient pressure using 2 apparatus. The rate of mass loss increased with temperature and air flow rate as expected, but the quantitative relationships could not be defined from the data due to contributions by other uncontrolled factors. It was concluded that the rotary evaporator is not suited for evaporation rate studies, but rather for producing samples suitable for use in other studies. Chemical analysis showed that the relative abundance distributions of target n-alkane hydrocarbons varied with the degree of weathering of an oil in a consistent manner at ambient pressure, regardless of the temperature, rate of air exchange or other factors related to the apparatus and procedure. The composition of the artificially weathered oil was also consistent with that from an open pan simulation of a weathered oil slick. Loss of water content varied with the conditions of evaporation because of the differential rates of evaporation due to relative humidity considerations. It was concluded that weathering

  2. Freezing of Water Droplet due to Evaporation

    Science.gov (United States)

    Satoh, Isao; Fushinobu, Kazuyoshi; Hashimoto, Yu

    In this study, the feasibility of cooling/freezing of phase change.. materials(PCMs) due to evaporation for cold storage systems was experimentally examined. A pure water was used as the test PCM, since the latent heat due to evaporation of water is about 7 times larger than that due to freezing. A water droplet, the diameter of which was 1-4 mm, was suspended in a test cell by a fine metal wire (O. D.= 100μm),and the cell was suddenly evacuated up to the pressure lower than the triple-point pressure of water, so as to enhance the evaporation from the water surface. Temperature of the droplet was measured by a thermocouple, and the cooling/freezing behavior and the temperature profile of the droplet surface were captured by using a video camera and an IR thermo-camera, respectively. The obtained results showed that the water droplet in the evacuated cell is effectively cooled by the evaporation of water itself, and is frozen within a few seconds through remarkable supercooling state. When the initial temperature of the droplet is slightly higher than the room temperature, boiling phenomena occur in the droplet simultaneously with the freezing due to evaporation. Under such conditions, it was shown that the degree of supercooling of the droplet is reduced by the bubbles generated in the droplet.

  3. Mathematical modeling of wiped-film evaporators

    International Nuclear Information System (INIS)

    Sommerfeld, J.T.

    1976-05-01

    A mathematical model and associated computer program were developed to simulate the steady-state operation of wiped-film evaporators for the concentration of typical waste solutions produced at the Savannah River Plant. In this model, which treats either a horizontal or a vertical wiped-film evaporator as a plug-flow device with no backmixing, three fundamental phenomena are described: sensible heating of the waste solution, vaporization of water, and crystallization of solids from solution. Physical property data were coded into the computer program, which performs the calculations of this model. Physical properties of typical waste solutions and of the heating steam, generally as analytical functions of temperature, were obtained from published data or derived by regression analysis of tabulated or graphical data. Preliminary results from tests of the Savannah River Laboratory semiworks wiped-film evaporators were used to select a correlation for the inside film heat transfer coefficient. This model should be a useful aid in the specification, operation, and control of the full-scale wiped-film evaporators proposed for application under plant conditions. In particular, it should be of value in the development and analysis of feed-forward control schemes for the plant units. Also, this model can be readily adapted, with only minor changes, to simulate the operation of wiped-film evaporators for other conceivable applications, such as the concentration of acid wastes

  4. Uranium concentration monitor manual, secondary intermediate evaporator

    International Nuclear Information System (INIS)

    Russo, P.A.; Sprinkle, J.K. Jr.; Slice, R.W.; Strittmatter, R.B.

    1985-08-01

    This manual describes the design, operation, and measurement control procedures for the automated uranium concentration monitor on the secondary intermediate evaporator at the Oak Ridge Y-12 Plant. The nonintrusive monitor provides a near-real time readout of uranium concentration in the return loop of time recirculating evaporator for purposes of process monitoring and control. A detector installed near the bottom of the return loop is used to acquire spectra of gamma rays from the evaporator solutions during operation. Pulse height analysis of each spectrum gives the information required to deduce the concentration of uranium in the evaporator solution in near-real time. The visual readout of concentration is updated at the end of every assay cycle. The readout includes an alphanumeric display of uranium concentration and an illuminated, colored LED (in an array of colored LEDs) indicating whether the measured concentration is within (or above or below) the desired range. An alphanumeric display of evaporator solution acid molarity is also available to the operator. 9 refs., 16 figs., 4 tabs

  5. Optimal control of evaporator and washer plants

    International Nuclear Information System (INIS)

    Niemi, A.J.

    1989-01-01

    Tests with radioactive tracers were used for experimental analysis of a multiple-effect evaporator plant. The residence time distribution of the liquor in each evaporator was described by one or two perfect mixers with time delay and by-pass flow terms. The theoretical model of a single evaporator unit was set up on the basis of its instantaneous heat and mass balances and such models were fitted to the test data. The results were interpreted in terms of physical structures of the evaporators. Further model parameters were evaluated by conventional step tests and by measurements of process variables at one or more steady states. Computer simulation and comparison with the experimental results showed that the model produces a satisfactory response to solids concentration input and could be extended to cover the steam feed and liquor flow inputs. An optimal feedforward control algorithm was developed for a two unit, co-current evaporator plant. The control criterion comprised the deviations of the final solids content of liquor and the consumption of fresh steam, from their optimal steady-state values. In order to apply the algorithm, the model of the solids in liquor was reduced to two nonlinear differential equations. (author)

  6. Evaporation rate of water in hydrophobic confinement.

    Science.gov (United States)

    Sharma, Sumit; Debenedetti, Pablo G

    2012-03-20

    The drying of hydrophobic cavities is believed to play an important role in biophysical phenomena such as the folding of globular proteins, the opening and closing of ligand-gated ion channels, and ligand binding to hydrophobic pockets. We use forward flux sampling, a molecular simulation technique, to compute the rate of capillary evaporation of water confined between two hydrophobic surfaces separated by nanoscopic gaps, as a function of gap, surface size, and temperature. Over the range of conditions investigated (gaps between 9 and 14 Å and surface areas between 1 and 9 nm(2)), the free energy barrier to evaporation scales linearly with the gap between hydrophobic surfaces, suggesting that line tension makes the predominant contribution to the free energy barrier. The exponential dependence of the evaporation rate on the gap between confining surfaces causes a 10 order-of-magnitude decrease in the rate when the gap increases from 9 to 14 Å. The computed free energy barriers are of the order of 50 kT and are predominantly enthalpic. Evaporation rates per unit area are found to be two orders of magnitude faster in confinement by the larger (9 nm(2)) than by the smaller (1 nm(2)) surfaces considered here, at otherwise identical conditions. We show that this rate enhancement is a consequence of the dependence of hydrophobic hydration on the size of solvated objects. For sufficiently large surfaces, the critical nucleus for the evaporation process is a gap-spanning vapor tube.

  7. Evaporation Behavior and Characterization of Eutectic Solvent and Ibuprofen Eutectic Solution.

    Science.gov (United States)

    Phaechamud, Thawatchai; Tuntarawongsa, Sarun; Charoensuksai, Purin

    2016-10-01

    Liquid eutectic system of menthol and camphor has been reported as solvent and co-solvent for some drug delivery systems. However, surprisingly, the phase diagram of menthol-camphor eutectic has not been reported previously. The evaporation behavior, physicochemical, and thermal properties of this liquid eutectic and ibuprofen eutectic solution were characterized in this study. Differential scanning calorimetry (DSC) analysis indicated that a eutectic point of this system was near to 1:1 menthol/camphor and its eutectic temperature was -1°C. The solubility of ibuprofen in this eutectic was 282.11 ± 6.67 mg mL(-1) and increased the drug aqueous solubility fourfold. The shift of wave number from Fourier transform infrared spectroscopy (FTIR) indicated the hydrogen bonding of each compound in eutectic mixture. The weight loss from thermogravimetric analysis of menthol and camphor related to the evaporation and sublimation, respectively. Menthol demonstrated a lower apparent sublimation rate than camphor, and the evaporation rate of eutectic solvent was lower than the sublimation rate of camphor but higher than the evaporation of menthol. The evaporation rate of the ibuprofen eutectic solution was lower than that of the eutectic solvent because ibuprofen did not sublimate. This eutectic solvent prolonged the ibuprofen release with diffusion control. Thus, the beneficial information for thermal behavior and related properties of eutectic solvent comprising menthol-camphor and ibuprofen eutectic solution was attained successfully. The rather low evaporation of eutectic mixture will be beneficial for investigation and tracking the mechanism of transformation from nanoemulsion into nanosuspension in the further study using eutectic as oil phase.

  8. Study of thermal conductivity of multilayer insulation

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, D; Sundaram, S; Nath, G K; Sethuram, N P; Chandrasekharan, T; Varadarajan, T G [Heavy Water Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    This paper presents experimental determination of the apparent thermal conductivity of multilayer insulation for a cryogenic system. The variation of thermal conductivity with residual gas pressure is studied and the optimum vacuum for good insulating performance is determined. Evaporation loss technique for heat-inleak determination is employed. (author). 3 refs., 3 figs.

  9. Study of thermal conductivity of multilayer insulation

    International Nuclear Information System (INIS)

    Dutta, D.; Sundaram, S.; Nath, G.K.; Sethuram, N.P.; Chandrasekharan, T.; Varadarajan, T.G.

    1994-01-01

    This paper presents experimental determination of the apparent thermal conductivity of multilayer insulation for a cryogenic system. The variation of thermal conductivity with residual gas pressure is studied and the optimum vacuum for good insulating performance is determined. Evaporation loss technique for heat-inleak determination is employed. (author)

  10. Long Duration Testing of a Spacesuit Water Membrane Evaporator Prototype

    Science.gov (United States)

    Bue, Grant C.; Makinen, Janice; Cox, Marlon; Watts, Carly; Campbell, Colin; Vogel, Matthew; Colunga, Aaron; Conger, Bruce

    2012-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is a heat-rejection device that is being developed to perform thermal control for advanced spacesuits. Cooling is achieved by circulating water from the liquid cooling garment (LCG) through hollow fibers (HoFi s), which are small hydrophobic tubes. Liquid water remains within the hydrophobic tubes, but water vapor is exhausted to space, thereby removing heat. A SWME test article was tested over the course of a year, for a total of 600 cumulative hours. In order to evaluate SWME tolerance to contamination due to constituents caused by distillation processes, these constituents were allowed to accumulate in the water as evaporation occurred. A test article was tested over the course of a year for a total of 600 cumulative hours. The heat rejection performance of the SWME degraded significantly--below 700 W, attributable to the accumulation of rust in the circulating loop and biofilm growth. Bubble elimination capability, a feature that was previously proven with SWME, was compromised during the test, most likely due to loss of hydrophobic properties of the hollow fibers. The utilization of water for heat rejection was shown not to be dependent on test article, life cycle, heat rejection rate, or freezing of the membranes.

  11. Water evaporation from bare soil at Paraiba, Brazil

    International Nuclear Information System (INIS)

    Lima, Jose Romualdo de Sousa; Antonino, Antonio Celso D.; Lira, Carlos A. Brayner de O.; Maciel Netto, Andre; Silva, Ivandro de Franca da; Souza, Jeffson Cavalcante de

    2002-01-01

    Measurements were accomplished in a 4,0 ha area in Centro de Ciencias Agrarias, UFPB, Areia City, Paraiba State, Brazil (6 deg C 58'S, 35 deg C 41'W and 645 m), aiming to determine water evaporation from bare soil, by energy and water balance approaches. Rain gauge, net radiometer, pyranometer and sensor for measuring the temperature and the relative humidity of the air and the speed of the wind, in two levels above the soil surface, were used to solve the energy balance equations. In the soil, two places were fitted with instruments, each one with two thermal probes, installed horizontally in the depths z1 = 2,0 cm and z2 = 8,0 cm, and a heat flux plate, for the measurement of the heat flux in the soil, the z1 = 5,0 cm. The measured data were stored every 30 minutes in a data logger. For the calculation of the water balance, three tensio-neutronics sites were installed, containing: an access tube for neutrons probe and eight tensiometers. The values of soil evaporation obtained by water balance were lower than obtained by energy balance because of the variability of the water balance terms. (author)

  12. Study on water evaporation rate from indoor swimming pools

    Directory of Open Access Journals (Sweden)

    Rzeźnik Ilona

    2017-01-01

    Full Text Available The air relative humidity in closed spaces of indoor swimming pools influences significantly on users thermal comfort and the stability of the building structure, so its preservation on suitable level is very important. For this purpose, buildings are equipped with HVAC systems which provide adequate level of humidity. The selection of devices and their technical parameters is made using the mathematical models of water evaporation rate in the unoccupied and occupied indoor swimming pool. In the literature, there are many papers describing this phenomena but the results differ from each other. The aim of the study was the experimental verification of published models of evaporation rate in the pool. The tests carried out on a laboratory scale, using model of indoor swimming pool, measuring 99cm/68cm/22cm. The model was equipped with water spray installation with six nozzles to simulate conditions during the use of the swimming pool. The measurements were made for conditions of sports pools (water temperature 24°C and recreational swimming pool (water temperature 34°C. According to the recommendations the air temperature was about 2°C higher than water temperature, and the relative humidity ranged from 40% to 55%. Models Shah and Biasin & Krumm were characterized by the best fit to the results of measurements on a laboratory scale.

  13. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

    Science.gov (United States)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Wilkes, Robert; Kuehnel, Eric

    2014-01-01

    Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the Generation 4 Spacesuit Water Membrane Evaporator (Gen4 SWME). The SWME offers several advantages when compared with prior crewmember cooling technologies, including the ability to reject heat at increased atmospheric pressures, reduced loop infrastructure, and higher tolerance to fouling. Like its predecessors, Gen4 SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Test results from the backup cooling system which is based on a similar design and the subject of a companion paper, suggested that further volume reductions could be achieved through fiber density optimization. Testing was performed with four fiber bundle configurations ranging from 35,850 fibers to 41,180 fibers. The optimal configuration reduced the Gen4 SWME envelope volume by 15% from that of Gen3 while dramatically increasing the performance margin of the system. A rectangular block design was chosen over the Gen3 cylindrical design, for packaging configurations within the AEMU PLSS envelope. Several important innovations were made in the redesign of the backpressure valve which is used to control evaporation. A twin-port pivot concept was selected from among three low profile valve designs for superior robustness, control and packaging. The backpressure valve motor, the thermal control valve, delta pressure sensors and temperature sensors were incorporated into the manifold endcaps, also for packaging considerations. Flight-like materials including a titanium housing were used for all components. Performance testing

  14. Isotopic fractionation of soil water during evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Leopoldo, P R [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil); Salati, E; Matsui, E [Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

    1974-07-01

    The study of the variation of D/H relation in soil water during evaporation is studied. The isotopic fractionation of soil water has been observed in two soils of light and heavy texture. Soil columns were utilized. Soil water was extracted in a system operated under low pressure and the gaseous hydrogen was obtained by decomposition of the water and was analyzed in a GD-150 mass spectrometer for deuterium content. The variation of the delta sub(eta) /sup 0///sub 00/ value during evaporation showed that for water held at potentials below 15 atm, the deuterium content of soil water stays practically constant. For water held at potentials higher than 15 atm, corresponding to the third stage of evaporation, there is a strong tendency of a constant increase of delta sub(eta) /sup 0///sub 00/ of the remaining water.

  15. Field evaporation test of uranium tailings solution

    International Nuclear Information System (INIS)

    Chandler, B.L.; Shepard, T.A.; Stewart, T.A.

    1985-01-01

    A field experiment was performed to observe the effect on evaporation rate of a uranium tailings impoundment pond water as salt concentration of the water increased. The duration of the experiment was long enough to cause maximum salt concentration of the water to be attained. The solution used in the experiment was tailings pond water from an inactive uranium tailings disposal site in the initial stages of reclamation. The solution was not neutralized. The initial pH was about 1.0 decreasing to a salt gel at the end of the test. The results of the field experiment show a gradual and slight decrease in evaporation efficiency. This resulted as salt concentrations increased and verified the practical effectiveness of evaporation as a water removal method. In addition, the physical and chemical nature of the residual salts suggest that no long-term stability problem would likely result due to their presence in the impoundment during or after reclamation

  16. Method of suppressing evaporation loss of ruthenium

    International Nuclear Information System (INIS)

    Muromura, Tadazumi; Sato, Tadashi.

    1987-01-01

    Purpose: To prevent evaporation loss of ruthenium from liquid wastes by adding an aluminum compound upon applying evaporating and drying to solid treatment to reprocessing liquid wastes for spent fuels. Method: An aluminum compound such as aluminum nitrate or aluminum hydroxide to reprocessing liquid wastes of spent fuels such that aluminum/ruthenium mixing ratio corresponds to 1.3 - 70.0 by g/atom ratio (0.34 - 187 by weight ratio), and the liquid mixture is heated to a temperature of about 130 deg C to be evaporated and dried to solidness. This enables to recover ruthenium without settling and depositing insoluble matters in the liquid wastes and without decomposing nitric acid. (Yoshino, Y.)

  17. Evaporation of boric acid from sea water

    Energy Technology Data Exchange (ETDEWEB)

    Gast, J A; Thompson, T G

    1959-01-01

    Previous investigators have shown that the boron-chlorinity ratios of rain waters are many times greater than the boron-chlorinity ratio of sea water. The presence of boron in the atmosphere has been attributed to sea spray, volcanic activity, accumulation in dust, evaporation from plants, and industrial pollution. In this paper data are presented to demonstrate that boric acid in sea water has a vapor pressure at ordinary temperatures of the sea and, when sea water evaporates, boric acid occurs in the condensate of the water vapor. It is postulated that, while some of the boron in the atmosphere can be attributed to the sources mentioned above, most of the boric acid results from evaporation from the sea.

  18. Fate of sulfur mustard on soil: Evaporation, degradation, and vapor emission.

    Science.gov (United States)

    Jung, Hyunsook; Kah, Dongha; Chan Lim, Kyoung; Lee, Jin Young

    2017-01-01

    After application of sulfur mustard to the soil surface, its possible fate via evaporation, degradation following absorption, and vapor emission after decontamination was studied. We used a laboratory-sized wind tunnel, thermal desorber, gas chromatograph-mass spectrometry (GC-MS), and 13 C nuclear magnetic resonance ( 13 C NMR) for systematic analysis. When a drop of neat HD was deposited on the soil surface, it evaporated slowly while being absorbed immediately into the matrix. The initial evaporation or drying rates of the HD drop were found to be power-dependent on temperature and initial drop volume. Moreover, drops of neat HD, ranging in size from 1 to 6 μL, applied to soil, evaporated at different rates, with the smaller drops evaporating relatively quicker. HD absorbed into soil remained for a month, degrading eventually to nontoxic thiodiglycol via hydrolysis through the formation of sulfonium ions. Finally, a vapor emission test was performed for HD contaminant after a decontamination process, the results of which suggest potential risk from the release of trace chemical quantities of HD into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Energy consumption for sugar manufacturing. Part I: Evaporation versus reverse osmosis

    International Nuclear Information System (INIS)

    Madaeni, S.S.; Zereshki, S.

    2010-01-01

    Removing water from various feeds is usually carried out using evaporation process especially in food industry. Due to the high latent heat of water, this unit operation results in consumption of unacceptable amount of energy. Finding low energy consuming processes which could be replaced with this process is still a challenge. The processes with no phase inversion may be considered for concentration purposes with reasonable energy consumption in comparison with the other various separation procedures. Reverse osmosis and most of the other membrane technologies are separation techniques without any change in the phase and therefore consume low amount of energy. Concentrating the sugar thin juice in the classical sugar manufacturing procedure is carried out using conventional evaporation. Reverse osmosis membranes may be used as a pre-concentration step to partially separate water from the sugar thin juice in combination with this part of the plant. Final concentration and thick juice preparation for crystallization may be carried out in the evaporation unit. In this study, membranes were employed for sugar thin juice concentration using a two-stage reverse osmosis process in two different arrangements. The energy consumption was calculated and compared for conventional evaporation versus reverse osmosis combined with evaporation. The results indicate that the employment of reverse osmosis membranes for concentrating the sugar thin juice leads to sensibly lower energy requirements. Furthermore, there is no thermal loss of sugar in the membrane process.

  20. Effects of solvent evaporation conditions on solvent vapor annealed cylinder-forming block polymer thin films

    Science.gov (United States)

    Grant, Meagan; Jakubowski, William; Nelson, Gunnar; Drapes, Chloe; Baruth, A.

    Solvent vapor annealing is a less time and energy intensive method compared to thermal annealing, to direct the self-assembly of block polymer thin films. Periodic nanostructures have applications in ultrafiltration, magnetic arrays, or other structures with nanometer dimensions, driving its continued interest. Our goal is to create thin films with hexagonally packed, perpendicular aligned cylinders of poly(lactide) in a poly(styrene) matrix that span the thickness of the film with low anneal times and low defect densities, all with high reproducibility, where the latter is paramount. Through the use of our computer-controlled, pneumatically-actuated, purpose-built solvent vapor annealing chamber, we have the ability to monitor and control vapor pressure, solvent concentration within the film, and solvent evaporation rate with unprecedented precision and reliability. Focusing on evaporation, we report on two previously unexplored areas, chamber pressure during solvent evaporation and the flow rate of purging gas aiding the evaporation. We will report our exhaustive results following atomic force microscopy analysis of films exposed to a wide range of pressures and flow rates. Reliably achieving well-ordered films, while occurring within a large section of this parameter space, was correlated with high-flow evaporation rates and low chamber pressures. These results have significant implications on other methods of solvent annealing, including ``jar'' techniques.

  1. Solubility of plutonium and waste evaporation

    International Nuclear Information System (INIS)

    Karraker, D.G.

    1993-01-01

    Chemical processing of irradiated reactor elements at the Savannah River Site separates uranium, plutonium and fission products; fission products and process-added chemicals are mixed with an excess of NaOH and discharged as a basic slurry into large underground tanks for temporary storage. The slurry is composed of base-insoluble solids that settle to the bottom of the tank; the liquid supemate contains a mixture of base-soluble chemicals--nitrates, nitrites aluminate, sulfate, etc. To conserve space in the waste tanks, the supemate is concentrated by evaporation. As the evaporation proceeds, the solubilities of some components are exceeded, and these species crystallize from solution. Normally, these components are soluble in the hot solution discharged from the waste tank evaporator and do not crystallize until the solution cools. However, concern was aroused at West Valley over the possibility that plutonium would precipitate and accumulate in the evaporator, conceivably to the point that a nuclear accident was possible. There is also a concern at SRS from evaporation of sludge washes, which arise from washing the base-insoluble solids (open-quote sludge close-quote) with ca. 1M NaOH to reduce the Al and S0 4 -2 content. The sludge washes of necessity extract a low level of Pu from the sludge and are evaporated to reduce their volume, presenting the possibility of precipitating Pu. Measurements of the solubility of Pu in synthetic solutions of similar composition to waste supernate and sludge washes are described in this report

  2. Understanding evaporation characteristics of a drop of distilled sulfur mustard (HD) chemical agent from stainless steel and aluminum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H., E-mail: junghs@add.re.kr; Lee, H.W.

    2014-05-01

    Highlights: • Evaporation rates of HD are obtained from stainless steel and aluminum substrates. • The rates increase with temperature and are linearly proportional to drop size. • HD evaporation from stainless steel follows only constant contact area mechanism. • HD evaporation from aluminum proceeds by a combined mechanism. - Abstract: We report herein the evaporation rates and mechanism of a drop of distilled sulfur mustard (HD) agent from stainless steel and aluminum substrates. For systematic analysis, we used a laboratory-sized wind tunnel, thermal desorption (TD) connected to gas chromatograph/mass spectrometry (GC/MS) and drop shape analysis (DSA). We found that the evaporation rates of HD from stainless steel and aluminum increased with temperature. The rates were also linearly proportional to drop size. The time-dependent contact angle measurement showed that the evaporation of the drop of HD proceeded only by constant contact area mechanism from stainless steel surface. On the other hand, the evaporation of HD from aluminum proceeded by a combined mechanism of constant contact area mode and constant contact angle mode. Our experimental data sets and analysis could be used to predict vapor and contact hazard persistence of chemical warfare agents (CWAs) in the air and on exterior surfaces with chemical releases, which assists the military decision influencing personnel safety and decontamination of the site upon a chemical attack event.

  3. Understanding evaporation characteristics of a drop of distilled sulfur mustard (HD) chemical agent from stainless steel and aluminum substrates

    International Nuclear Information System (INIS)

    Jung, H.; Lee, H.W.

    2014-01-01

    Highlights: • Evaporation rates of HD are obtained from stainless steel and aluminum substrates. • The rates increase with temperature and are linearly proportional to drop size. • HD evaporation from stainless steel follows only constant contact area mechanism. • HD evaporation from aluminum proceeds by a combined mechanism. - Abstract: We report herein the evaporation rates and mechanism of a drop of distilled sulfur mustard (HD) agent from stainless steel and aluminum substrates. For systematic analysis, we used a laboratory-sized wind tunnel, thermal desorption (TD) connected to gas chromatograph/mass spectrometry (GC/MS) and drop shape analysis (DSA). We found that the evaporation rates of HD from stainless steel and aluminum increased with temperature. The rates were also linearly proportional to drop size. The time-dependent contact angle measurement showed that the evaporation of the drop of HD proceeded only by constant contact area mechanism from stainless steel surface. On the other hand, the evaporation of HD from aluminum proceeded by a combined mechanism of constant contact area mode and constant contact angle mode. Our experimental data sets and analysis could be used to predict vapor and contact hazard persistence of chemical warfare agents (CWAs) in the air and on exterior surfaces with chemical releases, which assists the military decision influencing personnel safety and decontamination of the site upon a chemical attack event

  4. Enhancing mercury removal across air pollution control devices for coal-fired power plants by desulfurization wastewater evaporation.

    Science.gov (United States)

    Bin, Hu; Yang, Yi; Cai, Liang; Yang, Linjun; Roszak, Szczepan

    2017-10-09

    Desulfurization wastewater evaporation technology is used to enhance the removal of gaseous mercury (Hg) in conventional air pollution control devices (APCDs) for coal-fired power plants. Studies have affirmed that gaseous Hg is oxidized and removed by selective catalytic reduction (SCR), an electrostatic precipitator (ESP) and wet flue gas desulfurization (WFGD) in a coal-fired thermal experiment platform with WFGD wastewater evaporation. Effects of desulfurization wastewater evaporation position, evaporation temperature and chlorine ion concentration on Hg oxidation were studied as well. The Hg 0 oxidation efficiency was increased ranging from 30% to 60%, and the gaseous Hg removal efficiency was 62.16% in APCDs when wastewater evaporated before SCR. However, the Hg 0 oxidation efficiency was 18.99% and the gaseous Hg removal efficiency was 40.19% in APCDs when wastewater evaporated before ESP. The results show that WFGD wastewater evaporation before SCR is beneficial to improve the efficiency of Hg oxidized and removed in APCDs. Because Hg 2+ can be easily removed in ACPDs and WFGD wastewater in power plants is enriched with chlorine ions, this method realizes WFGD wastewater zero discharge and simultaneously enhances Hg removal in APCDs.

  5. Steady 3D Numerical Simulation of the Evaporator and Compensation Chamber of a Loop Heat Pipe

    Directory of Open Access Journals (Sweden)

    A. V. Nedayvozov

    2017-01-01

    Full Text Available The paper presents results of a steady three-dimensional numerical simulation of a flat evaporator and compensation chamber (CC of a loop heat pipe (LHP and describes a procedure of the thermal state calculation of the evaporator and the compensation chamber.The LHP is an efficient heat transfer device operating on the principle of evaporation-condensation cycle. It is successfully used in space technology and also to cool the heat-stressed components of electronic devices and computer equipment. The authors carried out a numerical study of the influence of the condensate pipeline length, immersed in water, on the thermal state of the evaporator and the compensation chamber.  The paper shows the influence of the mass forces field on the calculation results. Presents all the numerical studies carried out by the authors for a brass flat evaporator with a thermal load of 80 W. Water is used as a LHP heat-transfer fluid. Fields of temperature, pressure and velocity are presented for each design option.Based on the calculation results, the authors came to the following conclusions:Influence of the mass forces field for the LHP of this type is significant and leads to arising water vortex flow in the condensate pipeline and CC, thereby mixing and equalizing the water temperature in the CC and in the porous element, reducing the maximum temperature of the porous element;The increasing section length of the condensate pipeline in the CC leads to increasing velocity of the heat-transfer fluid in the CC and in the porous element, decreasing mixing zone of the condensate in the CC, and increasing temperature non-uniformity of the porous element.

  6. Black hole evaporation in conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bambi, Cosimo; Rachwał, Lesław [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Modesto, Leonardo [Department of Physics, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen 518055 (China); Porey, Shiladitya, E-mail: bambi@fudan.edu.cn, E-mail: lmodesto@sustc.edu.cn, E-mail: shilp@iitk.ac.in, E-mail: rachwal@fudan.edu.cn [Department of Physics, Indian Institute of Technology, 208016 Kanpur (India)

    2017-09-01

    We study the formation and the evaporation of a spherically symmetric black hole in conformal gravity. From the collapse of a spherically symmetric thin shell of radiation, we find a singularity-free non-rotating black hole. This black hole has the same Hawking temperature as a Schwarzschild black hole with the same mass, and it completely evaporates either in a finite or in an infinite time, depending on the ensemble. We consider the analysis both in the canonical and in the micro-canonical statistical ensembles. Last, we discuss the corresponding Penrose diagram of this physical process.

  7. Evaporative cooling enhanced cold storage system

    Science.gov (United States)

    Carr, P.

    1991-10-15

    The invention provides an evaporatively enhanced cold storage system wherein a warm air stream is cooled and the cooled air stream is thereafter passed into contact with a cold storage unit. Moisture is added to the cooled air stream prior to or during contact of the cooled air stream with the cold storage unit to effect enhanced cooling of the cold storage unit due to evaporation of all or a portion of the added moisture. Preferably at least a portion of the added moisture comprises water condensed during the cooling of the warm air stream. 3 figures.

  8. Sea water desalination by horizontal tubes evaporator

    International Nuclear Information System (INIS)

    Mohammadi, H.K.; Mohit, M.

    1986-01-01

    Desalinated water supplies are one of the problems of the nuclear power plants located by the seas. This paper explains saline water desalination by a Horizontal Tube Evaporator (HTE) and compares it with flash evaporation. A thermo compressor research project using HTE method has been designed, constructed, and operated at the Esfahan Nuclear Technology Center ENTC. The poject's ultimate goal is to obtain empirical formulae based on data gathered during operation of the unit and its subsequent development towards design and construction of desalination plants on an industrial scale

  9. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    CERN Document Server

    Andresen, G B; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A; Hydomako, R; Jonsell, S; Kurchaninov, L; Lambo, R; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wilding, D; Wurtele, J S; Yamazaki, Y

    2010-01-01

    We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9~K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

  10. Semiclassical approach to black hole evaporation

    International Nuclear Information System (INIS)

    Lowe, D.A.

    1993-01-01

    Black hole evaporation may lead to massive or massless remnants, or naked singularities. This paper investigates this process in the context of two quite different two-dimensional black hole models. The first is the original Callan-Giddings-Harvey-Strominger (CGHS) model, the second is another two-dimensional dilaton-gravity model, but with properties much closer to physics in the real, four-dimensional, world. Numerical simulations are performed of the formation and subsequent evaporation of black holes and the results are found to agree qualitatively with the exactly solved modified CGHS models, namely, that the semiclassical approximation breaks down just before a naked singularity appears

  11. An aluminium evaporation source for ion plating

    International Nuclear Information System (INIS)

    Walley, P.A.; Cross, K.B.

    1977-01-01

    Ion plating with aluminium is becoming increasingly accepted as a method of anti-corrosion surface passivation, the usual requirements being for a layer between 12 and 50 microns in thickness, (0.0005 to 0.002). The evaporation system described here offers a number of advantages over high power electron beam sources when used for aluminium ion plating. The source consists of a resistively heated, specially shaped, boron nitride-titanium diboride boat and a metering feed system. Its main features are small physical size, soft vacuum compatibility, low power consumption and metered evaporation output. (author)

  12. Defense Waste Processing Facility Recycle Stream Evaporation

    International Nuclear Information System (INIS)

    STONE, MICHAEL

    2006-01-01

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) stabilizes high level radioactive waste (HLW) by vitrification of the waste slurries. DWPF currently produces approximately five gallons of dilute recycle for each gallon of waste vitrified. This recycle stream is currently sent to the HLW tank farm at SRS where it is processed through the HLW evaporators with the concentrate eventually sent back to the DWPF for stabilization. Limitations of the HLW evaporators and storage space constraints in the tank farm have the potential to impact the operation of the DWPF and could limit the rate that HLW is stabilized. After an evaluation of various alternatives, installation of a dedicated evaporator for the DWPF recycle stream was selected for further evaluation. The recycle stream consists primarily of process condensates from the pretreatment and vitrification processes. Other recycle streams consist of process samples, sample line flushes, sump flushes, and cleaning solutions from the decontamination and filter dissolution processes. The condensate from the vitrification process contains some species, such as sulfate, that are not appreciably volatile at low temperature and could accumulate in the system if 100% of the evaporator concentrate was returned to DWPF. These species are currently removed as required by solids washing in the tank farm. The cleaning solutions are much higher in solids content than the other streams and are generated 5-6 times per year. The proposed evaporator would be required to concentrate the recycle stream by a factor of 30 to allow the concentrate to be recycled directly to the DWPF process, with a purge stream sent to the tank farm as required to prevent buildup of sulfate and similar species in the process. The overheads are required to meet stringent constraints to allow the condensate to be sent directly to an effluent treatment plant. The proposed evaporator would nearly de-couple the DWPF process from the

  13. Experiments on Evaporative Emissions in Ventilated Rooms

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Heiselberg, Per

    In many new buildings the indoor air quality is affected by emissions of volatile organic compounds (VOCs) from building materials. The emission process may be controlled either by diffusion inside the material or evaporation from the surface but it always involves mass transfer across the boundary...... layer at the surface-air-interface. Experiments at different velocity levels were performed in a full-scale ventilated chamber to investigate the influence of local airflow on the evaporative emission from a surface. The experiments included velocity measurements in the flow over the surface...

  14. Evaporation-induced assembly of biomimetic polypeptides

    International Nuclear Information System (INIS)

    Keyes, Joseph; Junkin, Michael; Cappello, Joseph; Wu Xiaoyi; Wong, Pak Kin

    2008-01-01

    We report an evaporation assisted plasma lithography (EAPL) process for guided self-assembly of a biomimetic silk-elastinlike protein (SELP). We demonstrate the formation of SELP structures from millimeter to submicrometer range on plasma-treatment surface templates during an evaporation-induced self-assembly process. The self-assembly processes at different humidities and droplet volumes were investigated. The process occurs efficiently in a window of optimized operating conditions found to be at 70% relative humidity and 8 μl volume of SELP solution. The EAPL approach provides a useful technique for the realization of functional devices and systems using these biomimetic materials

  15. New evaporator station for the center for accelerator target science

    Science.gov (United States)

    Greene, John P.; Labib, Mina

    2018-05-01

    As part of an equipment grant provided by DOE-NP for the Center for Accelerator Target Science (CATS) initiative, the procurement of a new, electron beam, high-vacuum deposition system was identified as a priority to insure reliable and continued availability of high-purity targets. The apparatus is designed to contain TWO electron beam guns; a standard 4-pocket 270° geometry source as well as an electron bombardment source. The acquisition of this new system allows for the replacement of TWO outdated and aging vacuum evaporators. Also included is an additional thermal boat source, enhancing our capability within this deposition unit. Recommended specifications for this system included an automated, high-vacuum pumping station, a deposition chamber with a rotating and heated substrate holder for uniform coating capabilities and incorporating computer-controlled state-of-the-art thin film technologies. Design specifications, enhanced capabilities and the necessary mechanical modifications for our target work are discussed.

  16. Melt and vapor characteristics in an electron beam evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Blumenfeld, L.; Fleche, J.L.; Gonella, C.; Soubbaramayer

    1994-12-31

    Two different approaches have been compared for the calculation of the free surface temperature Ts in cerium or copper evaporation experiments: the first method considers properties of the melt: an empirical law is used to take into account turbulent thermal convection, instabilities and characterization of the free surface. The second method considers the vapor flow expansion and connects Ts to the measured terminal temperature and terminal mean parallel velocity of the vapor jet, by direct simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high characterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that Ts and the Knudsen number at the vapour source reach a threshold when the beam power increases. (author). 12 figs., 1 tab., 21 refs.

  17. A numerical study of bulk evaporation and condensation problem

    International Nuclear Information System (INIS)

    Ding, Z.; Anghaie, S.

    1996-01-01

    A numerical model is developed to simulate the dynamic behavior of bulk evaporation and condensation process in an encapsulated container with internal heat generation at micro-gravity level. Thermal performance of a multi-phase system with internal heat generation is investigated. The numerical simulation yields the evolution of the bulk liquid-vapor phase change process. This includes the evolution of the liquid-vapor interface, the formation and development of the liquid film covering the side wall surface, the temperature distribution and the convection flow field. An example of such systems is a phase change nuclear fuel element which was first introduced by Ding and Anghaie with application in high temperature space nuclear power and propulsion systems

  18. Gravity, quantum theory and the evaporation of black holes. [Review

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, D C [Tata Inst. of Fundamental Research, Bombay (India)

    1977-06-01

    Recent developments in blackhole physics are reviewed. It is pointed out that black hole thermodynamics is a theory of exceptional unity and elegance. Starting from the discovery of thermal emission from black holes (evaporation process) by Hawking, the four thermodynamic laws they obey, the nonzero temperature and entropy, angular momentum and charge of the black holes are dealt with. The influence of this thermodynamics on quantum theory and gravitation is discussed in relation to particle creation and quantum gravity. The formation and basic properties of black holes are described in terms of significant milestones. The decade-long development of black hole thermodynamics from 1963-73 is highlighted. The fundamental issues arising in particle physics as a result of these discoveries are discussed.

  19. Elementary introduction into thermal desalination of saline waters

    International Nuclear Information System (INIS)

    Froehner, K.R.

    1979-01-01

    The principle of thermal conversion of saline waters into potable water are described from an elementary point of view in an easy understandable manner, covering distillation, submerged coil evaporation, flash evaporation, multiple effect distillation, vapour compression, and solar distillation in simple solar stills. (orig.)

  20. Experimental study on operating parameters of miniature loop heat pipe with flat evaporator

    International Nuclear Information System (INIS)

    Wang Shuangfeng; Huo Jiepeng; Zhang Xianfeng; Lin Zirong

    2012-01-01

    Miniature loop heat pipe (MLHP) with flat evaporator has been proved that it has the capability to fulfill the demand for the thermal management of high-power electronic system. To employ MLHP into practical application and obtain the best operating parameters, a copper-water MLHP with flat evaporator of 8 mm thick was fabricated and tested in the condition of different condenser locations and operating orientations. The results show that the condenser located close to the evaporator outlet and adverse orientation have positive impact on the operating temperature of the loop, but negative impact on the cooling capability of condenser. For better understanding of their effect on the heat transfer characteristics of MLHP, the start-up behaviors, thermal performance and the operating regimes are explored in detail. - Highlights: ► A copper-water MLHP with flat evaporator of only 8 mm thick was fabricated. ► The MLHP can be applied to electronic cooling. ► The effect of condenser locations was investigated for the first time. ► The experimental results were discussed and analyzed comprehensively. ► Some practical solutions for disadvantages of LHP operation were provided.