WorldWideScience

Sample records for thermoacoustic mixture separation

  1. Effect of temperature on thermoacoustic properties of olive oil in alcohol mixtures

    International Nuclear Information System (INIS)

    Shriwas, R S; Chimankar, O P; Tabhane, P V; Dange, S P; Tembhurkar, Y D

    2012-01-01

    The ultrasonic studies in liquids are great use in understanding the nature and strength of molecular interactions. Recently ultrasonic is the rapidly growing field research, which has been used in the food industry for both analysis and modification of food products. This paper presents ultrasonic velocity, density, adiabatic compressibility in olive oil with alcohol at different concentration that has been measured in the temperature range from 283.15K to 298.15K. The Moelwyn-Hughes parameter has been utilised to establish some simple relations between the available volumes, Bayer's non- linearity parameter, internal pressure, van der Waal's constant, Debye temperature etc. a relationship among the isobaric, isothermal and isochoric thermo-acoustical parameter have been studied and analyzed in the case olive oil with alcohol mixture. The present treatments had the distinct advantages of the thermo-acoustic parameters in the particular mixture.

  2. Turbulent Flow Modification With Thermoacoustic Waves for Separation Control

    Science.gov (United States)

    2017-08-24

    respectively. At the outlet, the time-average flow is set to be the target state of the sponge zone. In this section, the effects of momentum thickness...Turbulent Flow Modification With Thermoacoustic Waves For Separation Control The views, opinions and/or findings contained in this report are those...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. Florida State University Sponsored Research Administration 874

  3. Critical Temperature Differences of a Standing Wave Thermoacoustic Prime Mover with Various Helium-Based Binary Mixture Working Gases

    Science.gov (United States)

    Setiawan, Ikhsan; Nohtomi, Makoto; Katsuta, Masafumi

    2015-06-01

    Thermoacoustic prime movers are energy conversion devices which convert thermal energy into acoustic work. The devices are environmentally friendly because they do not produce any exhaust gases. In addition, they can utilize clean energy such as solar-thermal energy or waste heat from internal combustion engines as the heat sources. The output mechanical work of thermoacoustic prime movers are usually used to drive a thermoacoustic refrigerator or to generate electricity. A thermoacoustic prime mover with low critical temperature difference is desired when we intend to utilize low quality of heat sources such as waste heat and sun light. The critical temperature difference can be significantly influenced by the kinds of working gases inside the resonator and stack's channels of the device. Generally, helium gas is preferred as the working gas due to its high sound speed which together with high mean pressure will yield high acoustic power per unit volume of the device. Moreover, adding a small amount of a heavy gas to helium gas may improve the efficiency of thermoacoustic devices. This paper presents numerical study and estimation of the critical temperature differences of a standing wave thermoacoustic prime mover with various helium-based binary-mixture working gases. It is found that mixing helium (He) gas with other common gases, namely argon (Ar), nitrogen (N2), oxygen (O2), and carbon dioxide (CO2), at appropriate pressures and molar compositions, reduce the critical temperature differences to lower than those of the individual components of the gas mixtures. In addition, the optimum mole fractions of Hegas which give the minimum critical temperature differences are shifted to larger values as the pressure increases, and tends to be constant at around 0.7 when the pressure increases more than 2 MPa. However, the minimum critical temperature differences slightly increase as the pressure increases to higher than 1.5 MPa. Furthermore, we found that the lowest

  4. Transmission eigenvalues and thermoacoustic tomography

    International Nuclear Information System (INIS)

    Finch, David; Hickmann, Kyle S

    2013-01-01

    The spectrum of the interior transmission problem is related to the unique determination of the acoustic properties of a body in thermoacoustic imaging. Under a non-trapping hypothesis, we show that sparsity of the interior transmission spectrum implies a range separation condition for the thermoacoustic operator. In odd dimensions greater than or equal to 3, we prove that the interior transmission spectrum for a pair of radially symmetric non-trapping sound speeds is countable, and conclude that the ranges of the associated thermoacoustic maps have only trivial intersection. (paper)

  5. Traveling-Wave Thermoacoustic Engines With Internal Combustion

    Science.gov (United States)

    Weiland, Nathan Thomas; Zinn, Ben T.; Swift, Gregory William

    2004-05-11

    Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

  6. Phase-exchange thermoacoustic engine

    Science.gov (United States)

    Offner, Avshalom; Meir, Avishai; Ramon, Guy Z.; WET Lab Team

    2017-11-01

    Phase-exchange thermoacoustic engines are reliable machines holding great promise in converting heat from low grade heat sources to mechanical or electrical power. In these engines the working fluid is a gas mixture containing one condensable component, decreasing the temperature difference required for ignition and steady state operation. Our experimental setup consists of a vertical acoustic resonator containing a mixture of air-water vapor. Water evaporates near the heat source, condenses at the heat sink and is drawn back down by gravity and capillary forces where it re-evaporates, sustaining a steady state closed thermodynamic cycle. We investigated the stability limit, namely the critical point at which temperature difference in the engine enables onset of self-excited oscillations, and the steady state of the engine. A simple theoretical model was derived, describing mechanisms of irreversible entropy generation and production of acoustic power in such engines. This model captures the essence in the differences between regular and phase-exchange thermoacoustic engines, and shows good agreement with experimental results of stability limit. Steady state results reveal not only a dramatic decrease in temperature difference, but also an increase in engine performances. The authors acknowledge the support from the Nancy and Stephen Grand Technion Energy Program (GTEP).

  7. Truck Thermoacoustic Generator and Chiller

    Energy Technology Data Exchange (ETDEWEB)

    Keolian, Robert

    2011-03-31

    This Final Report describes the accomplishments of the US Department of Energy (DOE) cooperative agreement project DE-FC26-04NT42113 - Truck Thermoacoustic Generator and Chiller - whose goal is to design, fabricate and test a thermoacoustic piezoelectric generator and chiller system for use on over-the-road heavy-duty-diesel trucks, driven alternatively by the waste heat of the main diesel engine exhaust or by a burner integrated into the thermoacoustic system. The thermoacoustic system would utilize engine exhaust waste heat to generate electricity and cab air conditioning, and would also function as an auxiliary power unit (APU) for idle reduction. The unit was to be tested in Volvo engine performance and endurance test cells and then integrated onto a Class 8 over-the-road heavy-duty-diesel truck for further testing on the road. The project has been a collaboration of The Pennsylvania State University Applied Research Laboratory, Los Alamos National Laboratory, Clean Power Resources Inc., and Volvo Powertrain (Mack Trucks Inc.). Cost share funding was provided by Applied Research Laboratory, and by Clean Power Resources Inc via its grant from Innovation Works - funding that was derived from the Commonwealth of Pennsylvania. Los Alamos received its funding separately through DOE Field Work Proposal 04EE09.

  8. Energy transfer modelling of active thermoacoustic engines via Lagrangian thermoacoustic dynamics

    International Nuclear Information System (INIS)

    Hong, Boe-Shong; Chou, Chia-Yu

    2014-01-01

    Highlights: • Resonant control on thermoacoustic engines to amplify power rating. • Least-action principle of thermoacoustic dynamics to shape engine chamber. • Spatiotemporal transfer function into feedback systems. • Conservation law of thermoacoustic storage to figure out engine cycles. • Robin boundary condition to identify flow leakage. - Abstract: This paper develops energy-transfer modelling of active thermoacoustic engines resonantly controlled on boundary for amplification of power rating toward satisfaction of renewable industry. Therein the wave equation of thermoacoustic dynamics in resonators with non-uniform media and boundary actuations is derived and then turned into a least-action principle. With this least-action principle, we obtain the governing equation of longitudinal resonators with spatially variant cross-section areas to investigate how to shape the resonator for boosting piston stroke and power-transmission efficiency. It is followed by spatiotemporal transfer-function modelling that functionally represents the dynamics and interprets the boundary actuations into internal inputs. This helps formulate the overall dynamics into feedback-interconnection between the thermoacoustic dynamics in the resonator and the mechatronic dynamics of the alternative current generator, so that synthesis of feedback systems can be applied to design the entire engine. Transfer-function modelling following least-action principle leads to the conservation law of thermoacoustic storage, which figures out engine cycles, the most fundamental principle in designing active thermoacoustic engines. Based on such feedback realization, digital signal processing is programmed to numerically assess power ratings of active designs

  9. Thermoacoustic refrigeration

    Science.gov (United States)

    Garrett, Steven L.; Hofler, Thomas J.

    1991-12-01

    A new refrigerator which uses resonant high amplitude sound in inert gases to pump heat is described and demonstrated. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). The thermoacoustic refrigerator has no sliding seals, requires no lubrication, uses only low-tolerance machine parts, and contains no expensive components. Because the compressor moving mass is typically small and the oscillation frequency is high, the small amount of vibration is very easily isolated. This low vibration and lack of sliding seals makes thermoacoustic refrigeration an excellent candidate for food refrigeration and commercial/residential air conditioning applications. The design, fabrication, and performance of the first practical, autonomous thermoacoustic refrigerator, which will be flown on the Space Shuttle (STS-42), are described, and designs for terrestrial applications are presented.

  10. Design and optimization of thermoacoustic devices

    International Nuclear Information System (INIS)

    Babaei, Hadi; Siddiqui, Kamran

    2008-01-01

    Thermoacoustics deals with the conversion of heat energy into sound energy and vice versa. It is a new and emerging technology which has a strong potential towards the development of sustainable and renewable energy systems by utilizing waste heat or solar energy. Although simple to fabricate, the designing of thermoacoustic devices is very challenging. In the present study, a comprehensive design and optimization algorithm is developed for designing thermoacoustic devices. The unique feature of the present algorithm is its ability to design thermoacoustically-driven thermoacoustic refrigerators that can serve as sustainable refrigeration systems. In addition, new features based on the energy balance are also included to design individual thermoacoustic engines and acoustically-driven thermoacoustic refrigerators. As a case study, a thermoacoustically-driven thermoacoustic refrigerator has been designed and optimized based on the developed algorithm. The results from the algorithm are in good agreement with that obtained from the computer code DeltaE

  11. Micro-Scale Thermoacoustics

    Science.gov (United States)

    Offner, Avshalom; Ramon, Guy Z.

    2016-11-01

    Thermoacoustic phenomena - conversion of heat to acoustic oscillations - may be harnessed for construction of reliable, practically maintenance-free engines and heat pumps. Specifically, miniaturization of thermoacoustic devices holds great promise for cooling of micro-electronic components. However, as devices size is pushed down to micro-meter scale it is expected that non-negligible slip effects will exist at the solid-fluid interface. Accordingly, new theoretical models for thermoacoustic engines and heat pumps were derived, accounting for a slip boundary condition. These models are essential for the design process of micro-scale thermoacoustic devices that will operate under ultrasonic frequencies. Stability curves for engines - representing the onset of self-sustained oscillations - were calculated with both no-slip and slip boundary conditions, revealing improvement in the performance of engines with slip at the resonance frequency range applicable for micro-scale devices. Maximum achievable temperature differences curves for thermoacoustic heat pumps were calculated, revealing the negative effect of slip on the ability to pump heat up a temperature gradient. The authors acknowledge the support from the Nancy and Stephen Grand Technion Energy Program (GTEP).

  12. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2006-01-01

    a method for underdetermined blind source separation of convolutive mixtures. The proposed framework is applicable for separation of instantaneous as well as convolutive speech mixtures. It is possible to iteratively extract each speech signal from the mixture by combining blind source separation...

  13. Heat transfer in a thermoacoustic process

    International Nuclear Information System (INIS)

    Beke, Tamas

    2012-01-01

    Thermoacoustic instability is defined as the excitation of acoustic modes in chambers with heat sources due to the coupling between acoustic perturbations and unsteady heat addition. The major objective of this paper is to achieve accurate theoretical results in a thermoacoustic heat transfer process. We carry out a detailed heat transfer analysis aimed at determining the stability–instability border of the thermoacoustic system. In this paper, we present a project type of physical examination and modelling task. We employed an electrically heated Rijke tube in our thermoacoustic project work. The aim of our project is to help our students enlarge their knowledge about thermodynamics, mainly about thermoacoustics, and develop their applied information technology and mathematical skills. (paper)

  14. Thermoacoustic refrigerator for space applications

    Science.gov (United States)

    Garrett, Steven L.; Adeff, Jay A.; Hofler, Thomas J.

    1993-10-01

    A new spacecraft cryocooler which uses resonant high-amplitude sound waves in inert gases to pump heat is described. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). A space-qualified thermoacoustic refrigerator was flown on the Space Shuttle Discovery (STS-42) in January, 1992. It was entirely autonomous, had no sliding seals, required no lubrication, used mostly low-tolerance machined parts, and contained no expensive components. Thermoacoustics is shown to be a competitive candidate for food refrigerator/freezers and commercial/residential air conditioners. The design and performance of the Space Thermo/Acoustic Refrigerator (STAR) is described.

  15. Method of determination of thermo-acoustic coolant instability boundaries in reactor core at NPPs with WWER

    International Nuclear Information System (INIS)

    Skalozubov, Volodymyr; Kolykhanov, Viktor; Kovryzhkin, Yuriy

    2007-01-01

    The regulatory body of Ukraine, the National Atomic Energy Company and the Scientific and Production Centre have led team-works concerned with previously unstudied factors or phenomena affecting reactor safety. As a result it is determined that the thermo-acoustic coolant instability conditions can appear in the core at definite operating WWER regimes. Considerable cyclic dynamic loads affect fuel claddings over thermo-acoustic pressure oscillations. These loads can result in inadmissible cassette design damage and containment damage. Taking into account calculation and experimental research authors submit a method of on-line assessment of WWER core state concerning thermo-acoustic coolant instability. According to this method, the thermo-acoustic coolant instability appearance conditions can be estimated using normal registered parameters (pressure, temperature, heat demand etc.). At operative modes, a WWER-1000 core is stable to tracheotomies oscillations, but reduction of coolant discharge through the core for some times can result in thermo-acoustic coolant instability. Thermo-acoustic instability appears at separate transitional modes concerned with reactor scram and unloading/loading at all power units. When thermo-acoustic instability begins in transitional modes, core elements are under influence of high-frequency coolant pressure pulsations for a long time (tens of hours)

  16. Sensitivity and Nonlinearity of Thermoacoustic Oscillations

    Science.gov (United States)

    Juniper, Matthew P.; Sujith, R. I.

    2018-01-01

    Nine decades of rocket engine and gas turbine development have shown that thermoacoustic oscillations are difficult to predict but can usually be eliminated with relatively small ad hoc design changes. These changes can, however, be ruinously expensive to devise. This review explains why linear and nonlinear thermoacoustic behavior is so sensitive to parameters such as operating point, fuel composition, and injector geometry. It shows how nonperiodic behavior arises in experiments and simulations and discusses how fluctuations in thermoacoustic systems with turbulent reacting flow, which are usually filtered or averaged out as noise, can reveal useful information. Finally, it proposes tools to exploit this sensitivity in the future: adjoint-based sensitivity analysis to optimize passive control designs and complex systems theory to warn of impending thermoacoustic oscillations and to identify the most sensitive elements of a thermoacoustic system.

  17. Centrifugal separation of mixture gases

    International Nuclear Information System (INIS)

    Zhou, M.S.; Chen, W.N.; Yin, Y.T.

    2008-01-01

    An attempt for single centrifugal separation of mixtures with different molecular formula was presented in this paper. The mixtures of SF 6 and CCl 3 F, and SF 6 and CCl 4 were chosen as the processing gases, which were prepared in three mass ratios, 0.5, 0.8 and 0.2, respectively. The separating characteristics such as the overall separation factors and the variation of cuts were studied. (author)

  18. Review of investigations in eco-friendly thermoacoustic refrigeration system

    Directory of Open Access Journals (Sweden)

    Raut Ashish S.

    2017-01-01

    Full Text Available To reduce greenhouse gas emissions, internationally research and development is intended to improve the performance of conventional refrigeration system also growth of new-fangled refrigeration technology of potentially much lesser ecological impact. This paper gives brief review of research and development in thermoacoustic refrigeration also the existing situation of thermoacoustic refrigeration system. Thermoacoustic refrigerator is a novel sort of energy conversion equipment which converts acoustic power into heat energy by thermoacoustic effect. Thermoacoustic refrigeration is an emergent refrigeration technology in which there are no moving elements or any environmentally injurious refrigerants during its working. The concept of thermoacoustic refrigeration system is explained, the growth of thermoacoustic refrigeration, various investigations into thermoacoustic refrigeration system, various optimization techniques to improve coefficient of performance, different stacks and resonator tube designs to improve heat transfer rate, various gases, and other parameters like sound generation have been reviewed.

  19. Separation of organic azeotropic mixtures by pervaporation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.

    1991-12-01

    Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.

  20. Physics of thermo-acoustic sound generation

    Science.gov (United States)

    Daschewski, M.; Boehm, R.; Prager, J.; Kreutzbruck, M.; Harrer, A.

    2013-09-01

    We present a generalized analytical model of thermo-acoustic sound generation based on the analysis of thermally induced energy density fluctuations and their propagation into the adjacent matter. The model provides exact analytical prediction of the sound pressure generated in fluids and solids; consequently, it can be applied to arbitrary thermal power sources such as thermophones, plasma firings, laser beams, and chemical reactions. Unlike existing approaches, our description also includes acoustic near-field effects and sound-field attenuation. Analytical results are compared with measurements of sound pressures generated by thermo-acoustic transducers in air for frequencies up to 1 MHz. The tested transducers consist of titanium and indium tin oxide coatings on quartz glass and polycarbonate substrates. The model reveals that thermo-acoustic efficiency increases linearly with the supplied thermal power and quadratically with thermal excitation frequency. Comparison of the efficiency of our thermo-acoustic transducers with those of piezoelectric-based airborne ultrasound transducers using impulse excitation showed comparable sound pressure values. The present results show that thermo-acoustic transducers can be applied as broadband, non-resonant, high-performance ultrasound sources.

  1. Method for separating gaseous mixtures of isotopes

    International Nuclear Information System (INIS)

    Neimann, H.J.; Schuster, E.; Kersting, A.

    1976-01-01

    A gaseous mixture of isotopes is separated by laser excitation of the isotope mixture with a narrow band of wavelengths, molecularly exciting mainly the isotope to be separated and thereby promoting its reaction with its chemical partner which is excited in a separate chamber. The excited isotopes and the chemical partner are mixed, perhaps in a reaction chamber to which the two excited components are conducted by very short conduits. The improvement of this method is the physical separation of the isotope mixture and its partner during excitation. The reaction between HCl and the mixture of 238 UF 6 and 235 UF 6 is discussed

  2. High temperature thermoacoustic heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, H.; Spoelstra, S. [Energy research Centre of the Netherlands, 1755 ZG Petten (Netherlands)

    2012-06-15

    Thermoacoustic technology can provide new types of heat pumps that can be deployed in different applications. A thermoacoustic heat pumps can for example be applied in dwellings to generate cooling or heating. Typically, space and water heating makes up about 60% of domestics and offices energy consumption. The application of heat pumps can contribute to achieve energy savings and environmental benefits by reducing CO2 and NOx emissions. This paper presents the study of a laboratory scale thermoacoustic-Stirling heat pump operating between 10C and 80C which can be applied in domestics and offices. The heat pump is driven by a thermoacoustic-Stirling engine. The experimental results show that the heat pump pumps 250 W of heat at 60C at a drive ratio of 3.6% and 200 W at 80C at a drive ratio of 3.5 %. The performance for both cases is about 40% of the Carnot performance. The design, construction, and performance measurements of the heat pump will be presented and discussed.

  3. High Temperature Thermoacoustic Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, H.; Spoelstra, S. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-07-15

    Thermoacoustic technology can provide new types of heat pumps that can be deployed in different applications. Thermoacoustic heat pumps can for example be applied in dwellings to generate cooling or heating. Typically, space and water heating makes up about 60% of domestic and office energy consumption. The application of heat pumps can contribute to achieve energy savings and environmental benefits by reducing CO2 and NOx emissions. This paper presents the study of a laboratory scale thermoacoustic-Stirling heat pump operating between 10C and 80C which can be applied in domestics and offices. The heat pump is driven by a thermoacoustic-Stirling engine. The experimental results show that the heat pump pumps 250 W of heat at 60C at a drive ratio of 3.6 % and 200 W at 80C at a drive ratio of 3.5 %. The performance for both cases is about 40% of the Carnot performance. The design, construction, and performance measurements of the heat pump will be presented and discussed.

  4. A high performance thermoacoustic Stirling-engine

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, M.E.H.; Spoelstra, S. [Energy research Centre of the Netherlands (ECN), PO Box 1, 1755 ZG Petten (Netherlands)

    2011-11-10

    In thermoacoustic systems heat is converted into acoustic energy and vice versa. These systems use inert gases as working medium and have no moving parts which makes the thermoacoustic technology a serious alternative to produce mechanical or electrical power, cooling power, and heating in a sustainable and environmentally friendly way. A thermoacoustic Stirling heat engine is designed and built which achieves a record performance of 49% of the Carnot efficiency. The design and performance of the engine is presented. The engine has no moving parts and is made up of few simple components.

  5. Experimental study of the influence of different resonators on thermoacoustic conversion performance of a thermoacoustic-Stirling heat engine.

    Science.gov (United States)

    Luo, E C; Ling, H; Dai, W; Yu, G Y

    2006-12-22

    In this paper, an experimental study of the effect of the resonator shape on the performance of a traveling-wave thermoacoustic engine is presented. Two different resonators were tested in the thermoacoustic-Stirling heat. One resonator is an iso-diameter one, and the other is a tapered one. To have a reasonable comparison reference, we keep the same traveling-wave loop, the same resonant frequency and the same operating pressure. The experiment showed that the resonator shape has significant influence on the global performance of the thermoacoustic-Stirling heat engine. The tapered resonator gives much better performance than the iso-diameter resonator. The tapered resonator system achieved a maximum pressure ratio of about 1.3, a maximum net acoustical power output of about 450 W and a highest thermoacoustic efficiency of about 25%.

  6. Studies on thermo-acoustic parameters in binary liquid mixtures of phosphinic acid (Cyanex 272) with different diluents at temperature 303.15 K: an ultrasonic study

    International Nuclear Information System (INIS)

    Kamila, Susmita; Jena, Satyaban; Swain, Bipin Bihari

    2005-01-01

    Acoustical investigations for the binary mixtures of phosphinic acid (Cyanex 272), used as liquid-liquid extractant, have been made in various diluents such as benzene, toluene, and xylene from ultrasonic velocity and density measurements at temperature 303.15 K and atmospheric pressure. This study involves evaluation of different thermo-acoustic parameters along with the excess properties, which are interpreted in the light of molecular interaction between a polar extractant, Cyanex 272 with non-polar diluent, benzene and weakly polar diluents, toluene and xylene. The excess values are correlated using Redlich-Kister polynomial equation, and corresponding adjustable parameters are derived

  7. Thermoacoustic magnetohydrodynamic electrical generator

    International Nuclear Information System (INIS)

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1986-01-01

    A thermoacoustic magnetohydrodynamic electrical generator is described comprising a magnet having a magnetic field, an elongate hollow housing containing an electrically conductive liquid and a thermoacoustic structure positioned in the liquid, heat exchange means thermally connected to the thermoacoustic structure for inducing the liquid to oscillate at an acoustic resonant frequency within the housing. The housing is positioned in the magnetic field and oriented such that the direction of the magnetic field and the direction of oscillatory motion of the liquid are substantially orthogonal to one another, first and second electrical conductor means connected to the liquid on opposite sides of the housing along an axis which is substantially orthogonal to both the direction of the magnetic field and the direction of oscillatory motion of the liquid, an alternating current output signal is generated in the conductor means at a frequency corresponding to the frequency of the oscillatory motion of the liquid

  8. Separation of alcohols from organic liquid mixtures by pervaporation

    NARCIS (Netherlands)

    Park, Hyun-Chae

    1993-01-01

    In the chemical industry, distillation is generally the preferred technique to separate a liquid mixture. However some liquid mixtures such as azeotropic mixtures, close-boiling hydrocarbons, and various isomers are difficult to separate by simple distillation. For the separation of these mixtures

  9. Co-registered photoacoustic, thermoacoustic, and ultrasound mouse imaging

    Science.gov (United States)

    Reinecke, Daniel R.; Kruger, Robert A.; Lam, Richard B.; DelRio, Stephen P.

    2010-02-01

    We have constructed and tested a prototype test bed that allows us to form 3D photoacoustic CT images using near-infrared (NIR) irradiation (700 - 900 nm), 3D thermoacoustic CT images using microwave irradiation (434 MHz), and 3D ultrasound images from a commercial ultrasound scanner. The device utilizes a vertically oriented, curved array to capture the photoacoustic and thermoacoustic data. In addition, an 8-MHz linear array fixed in a horizontal position provides the ultrasound data. The photoacoustic and thermoacoustic data sets are co-registered exactly because they use the same detector. The ultrasound data set requires only simple corrections to co-register its images. The photoacoustic, thermoacoustic, and ultrasound images of mouse anatomy reveal complementary anatomic information as they exploit different contrast mechanisms. The thermoacoustic images differentiate between muscle, fat and bone. The photoacoustic images reveal the hemoglobin distribution, which is localized predominantly in the vascular space. The ultrasound images provide detailed information about the bony structures. Superposition of all three images onto a co-registered hybrid image shows the potential of a trimodal photoacoustic-thermoacoustic-ultrasound small-animal imaging system.

  10. Heat Transfer in a Thermoacoustic Process

    Science.gov (United States)

    Beke, Tamas

    2012-01-01

    Thermoacoustic instability is defined as the excitation of acoustic modes in chambers with heat sources due to the coupling between acoustic perturbations and unsteady heat addition. The major objective of this paper is to achieve accurate theoretical results in a thermoacoustic heat transfer process. We carry out a detailed heat transfer analysis…

  11. Modelling of thermoacoustic phenomena in an electrically heated Rijke tube

    International Nuclear Information System (INIS)

    Beke, Tamas

    2010-01-01

    Thermoacoustic instability plays an important role in various technical applications, for instance in jet or rocket motors, thermoacoustic engines, pulse combustors and industrial burners. The main objective of this paper is to present the theory of thermoacoustic oscillations, and for this purpose a Rijke-type thermal device was built. The Rijke tube is a simple device open at both ends with a mean airflow and a concentrated heat source (a heated wire grid). It serves as a convenient prototypical example to understand thermoacoustic effects since it is a simplified thermoacoustic resonator; once excited, under certain conditions, it is capable of creating a sustained sound when thermal energy is added. In this paper we present a project that includes physical measuring, examination and modelling. We have employed electrically heated Rijke tubes in our thermoacoustic school project work, and present a numerical algorithm to predict the transition to instability; in this model the effects of the main system parameters are demonstrated. The aim of our project is to help our students enhance their knowledge about thermoacoustics and develop their applied information technology skills.

  12. Modelling of thermoacoustic phenomena in an electrically heated Rijke tube

    Energy Technology Data Exchange (ETDEWEB)

    Beke, Tamas, E-mail: tamasbe@gmail.co [Our Lady Catholic Institute, Kalocsa (Hungary)

    2010-11-15

    Thermoacoustic instability plays an important role in various technical applications, for instance in jet or rocket motors, thermoacoustic engines, pulse combustors and industrial burners. The main objective of this paper is to present the theory of thermoacoustic oscillations, and for this purpose a Rijke-type thermal device was built. The Rijke tube is a simple device open at both ends with a mean airflow and a concentrated heat source (a heated wire grid). It serves as a convenient prototypical example to understand thermoacoustic effects since it is a simplified thermoacoustic resonator; once excited, under certain conditions, it is capable of creating a sustained sound when thermal energy is added. In this paper we present a project that includes physical measuring, examination and modelling. We have employed electrically heated Rijke tubes in our thermoacoustic school project work, and present a numerical algorithm to predict the transition to instability; in this model the effects of the main system parameters are demonstrated. The aim of our project is to help our students enhance their knowledge about thermoacoustics and develop their applied information technology skills.

  13. Thermoacoustic power systems for space applications

    International Nuclear Information System (INIS)

    Backhaus, S.N.; Tward, E.; Pedach, M.

    2001-01-01

    Future NASA deep-space missions will require radioisotope-powered electric generators that are just as reliable as current RTGs, but more efficient and of higher specific power (W/kg). Thermoacoustic engines can convert high-temperature heat into acoustic, or PV, power without moving parts at 30% efficiency. Consisting of only tubes and a few heat exchangers, these engines are low mass and promise to be highly reliable. Coupling a thermoacoustic engine to a low-mass, highly reliable and efficient linear alternator will create a heat-driven electric generator suitable for deep-space applications. Data will be presented on the first tests of a demonstration thermoacoustic engine designed for the 100-Watt power range.

  14. Method of separation of gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, M.A.; Potapov, V.F.; Potapova, M.S.

    1980-04-05

    Gas mixtures are separated in a rectification tower by repeated counterflow contact of the heated gas flow and cool condensate as the pressure drops in each stage of separation (StR) and when condensate is added from StR with lower pressure to the StR with higher pressure. In order to reduce energy consumption noncondensing gas in amounts of 5-15 percent by weight of the amount of incoming gases are added. Hydrocarbon or carbon dioxide gas can be used as the latter. Example. To separate natural gas of the Shatlyk deposit of composition, percent by mo1: C1 -- 94.960; C2 -- 4.260; C3 -- 0.200; C4 -- 0.08; C4+B -- 0.51. It is enriched with carbon dioxide gas in an amount of 10 percent by weight. Upon rectification of the enriched hydrocarbon mixture separation is achieved at lower pressures of the gas mixture and less cold. This leads to reduction of energy consumption by 10-12 percent.

  15. Experimental investigation of a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine.

    Science.gov (United States)

    Luo, E C; Dai, W; Zhang, Y; Ling, H

    2006-12-22

    In this paper, a thermally-driven thermoacoustic refrigerator system without any moving part is reported. This refrigeration system consists of a thermoacoustic-Stirling heat engine and a thermoacoustic-Stirling refrigerator; that is, the former is the driving source for the latter. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it was found that the DC-flows had significant negative effect on the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems and worked very well. Then extensive experiments were made to test the influence of different parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65 degrees C, a cooling capacity of about 270 W at -20 degrees C and 405 W at 0 degrees C; in fact, the result showed a good prospect of the refrigeration system in room-temperature cooling such as food refrigeration and air-conditioning.

  16. Passive control of thermoacoustic oscillations with adjoint methods

    Science.gov (United States)

    Aguilar, Jose; Juniper, Matthew

    2017-11-01

    Strict pollutant regulations are driving gas turbine manufacturers to develop devices that operate under lean premixed conditions, which produce less NOx but encourage thermoacoustic oscillations. These are a form of unstable combustion that arise due to the coupling between the acoustic field and the fluctuating heat release in a combustion chamber. In such devices, in which safety is paramount, thermoacoustic oscillations must be eliminated passively, rather than through feedback control. The ideal way to eliminate thermoacoustic oscillations is by subtly changing the shape of the device. To achieve this, one must calculate the sensitivity of each unstable thermoacoustic mode to every geometric parameter. This is prohibitively expensive with standard methods, but is relatively cheap with adjoint methods. In this study we first present low-order network models as a tool to model and study the thermoacoustic behaviour of combustion chambers. Then we compute the continuous adjoint equations and the sensitivities to relevant parameters. With this, we run an optimization routine that modifies the parameters in order to stabilize all the resonant modes of a laboratory combustor rig.

  17. Theory and modeling of cylindrical thermo-acoustic transduction

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Lihong, E-mail: lhtong@ecjtu.edu.cn [School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi (China); Lim, C.W. [Department of Architecture and Civil Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Zhao, Xiushao; Geng, Daxing [School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi (China)

    2016-06-03

    Models both for solid and thinfilm-solid cylindrical thermo-acoustic transductions are proposed and the corresponding acoustic pressure solutions are obtained. The acoustic pressure for an individual carbon nanotube (CNT) as a function of input power is investigated analytically and it is verified by comparing with the published experimental data. Further numerical analysis on the acoustic pressure response and characteristics for varying input frequency and distance are also examined both for solid and thinfilm-solid cylindrical thermo-acoustic transductions. Through detailed theoretical and numerical studies on the acoustic pressure solution for thinfilm-solid cylindrical transduction, it is concluded that a solid with smaller thermal conductivity favors to improve the acoustic performance. In general, the proposed models are applicable to a variety of cylindrical thermo-acoustic devices performing in different gaseous media. - Highlights: • Theory and modeling both for solid and thinfilm-solid cylindrical thermo-acoustic transductions are proposed. • The modeling is verified by comparing with the published experimental data. • Acoustic response characteristics of cylindrical thermo-acoustic transductions are predicted by the proposed model.

  18. Separation of gas mixtures

    International Nuclear Information System (INIS)

    1981-01-01

    Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

  19. Design of a low-cost thermoacoustic electricity generator and its experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, Scott N [Los Alamos National Laboratory; Yu, Z [UNIV OF MANCHESTER; Jaworski, A J [UNIV OF MANCHESTER

    2010-01-01

    This paper describes the design and testing of a low cost thermoacoustic generator. A travelling-wave thermoacoustic engine with a configuration of a looped-tube resonator is designed and constructed to convert heat to acoustic power. A commercially available, low-cost loudspeaker is adopted as the alternator to convert the engine's acoustic power to electricity. The whole system is designed using linear thermoacoustic theory. The optimization of different parts of the thermoacoustic generator, as well as the matching between the thermoacoustic engine and the alternator are discussed in detail. A detailed comparison between the preliminary test results and linear thermoacoustic predictions is provided.

  20. Modelling of Thermoacoustic Phenomena in an Electrically Heated Rijke Tube

    Science.gov (United States)

    Beke, Tamas

    2010-01-01

    Thermoacoustic instability plays an important role in various technical applications, for instance in jet or rocket motors, thermoacoustic engines, pulse combustors and industrial burners. The main objective of this paper is to present the theory of thermoacoustic oscillations, and for this purpose a Rijke-type thermal device was built. The Rijke…

  1. Coincident effect characteristic in a thermoacoustic regenerator

    International Nuclear Information System (INIS)

    Liu Yicai; Xin Tianlong; Huang Qian; Shi Xiangnan; Chen Siming; Chen Lixin

    2011-01-01

    Many previous studies on characteristics of thermoacoustic regenerator are based on fluid micro-groups and their compression-expansion cycle. In this paper, coincident frequency is introduced to evaluate its acoustic characteristics by combining structural acoustic with structural vibration theories. The relationship among structure wave radiation and regenerator position, slab thickness, and properties of material are analyzed by numerical calculation. The results show that in the low-frequency thermoacoustic system, the coincident effect generated by higher frequency wave weakens the fundamental sound wave. While in the high-frequency thermoacoustic system, where the oscillating fundamental frequency is higher than the coincident frequency, the sound field strength is enhanced by stronger structure wave radiation because of the coincident effect.

  2. A numerical simulation method and analysis of a complete thermoacoustic-Stirling engine.

    Science.gov (United States)

    Ling, Hong; Luo, Ercang; Dai, Wei

    2006-12-22

    Thermoacoustic prime movers can generate pressure oscillation without any moving parts on self-excited thermoacoustic effect. The details of the numerical simulation methodology for thermoacoustic engines are presented in the paper. First, a four-port network method is used to build the transcendental equation of complex frequency as a criterion to judge if temperature distribution of the whole thermoacoustic system is correct for the case with given heating power. Then, the numerical simulation of a thermoacoustic-Stirling heat engine is carried out. It is proved that the numerical simulation code can run robustly and output what one is interested in. Finally, the calculated results are compared with the experiments of the thermoacoustic-Stirling heat engine (TASHE). It shows that the numerical simulation can agrees with the experimental results with acceptable accuracy.

  3. A linearly-acting variable-reluctance generator for thermoacoustic engines

    International Nuclear Information System (INIS)

    Hail, Claudio U.; Knodel, Philip C.; Lang, Jeffrey H.; Brisson, John G.

    2015-01-01

    Highlights: • A new design for a linear alternator for thermoacoustic power converters is presented. • A theoretical and semi-empirical model of the generator is developed and validated. • The variable-reluctance generator’s performance is experimentally characterized. • Scaling to higher frequency suggests efficient operation with thermoacoustic engines. - Abstract: A crucial element in a thermoacoustic power converter for reliable small-scale power generation applications is an efficient acoustic-to-electric energy converter. In this work, an acoustic-to-electric transducer for application with a back-to-back standing wave thermoacoustic engine, based on a linearly-acting variable-reluctance generator is proposed, built and experimentally tested. Static and dynamic experiments are performed on one side of the generator on a shaker table at 60 Hz with 5 mm peak-to-peak displacement for performance characterization. A theoretical and empirical model of the variable-reluctance generator are presented and validated with experimental data. A frequency scaling based on the empirical model indicates that a maximum power output of 84 W at 78% generator efficiency is feasible at the thermoacoustic engine’s operating frequency of 250 Hz, not considering power electronic losses. This suggests that the linearly-acting variable-reluctance generator can efficiently convert high frequency small amplitude acoustic oscillations to useful electricity and thus enables its integration into a thermoacoustic power converter

  4. Separation of organic azeotropic mixtures by pervaporation. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.

    1991-12-01

    Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center_dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.

  5. The role of thermoacoustics in the world of commercial cooling

    Science.gov (United States)

    Corey, John A.

    2005-09-01

    The science of thermoacoustics has been with us for nearly 30 years, but as yet few applications have made their way to the marketplace. Acoustic Stirling cryocoolers (also called pulse-tube Stirling or high-frequency pulse-tube coolers) have been the most successful commercial thermoacoustic devices, because they address a region of the cooling market in terms of temperature and cooling power that is not well served by existing technology. This talk will explore how thermoacoustics might fare in attempting to compete with existing technologies in refrigeration and air conditioning, what niche markets make the most sense as entry points, and how thermoacoustics compares to conventional (kinematic or free-piston) Stirling machines. In particular, why there are relatively few commercial Stirling devices in the marketplace (although Stirling cycle machines have been around for over 150 years) will be discussed, and what lessons learned with Stirlings are applicable to thermoacoustics.

  6. Generation of thermo-acoustic waves from pulsed solar/IR radiation

    Science.gov (United States)

    Rahman, Aowabin

    Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

  7. Method for separating gaseous mixtures of matter

    International Nuclear Information System (INIS)

    Schuster, E.; Kersting, A.

    1979-01-01

    Molecules to be separated from a mixture of matter of a chemical component are excited in a manner known per se by narrow-band light sources, and a chemical reaction partner for reacting with these molecules is admixed while supplied with energy by electromagnetic radiation or heating, and as additionally required for making chemical reactions possible. A method is described for separating gaseous mixtures of matter by exciting the molecules to be separated with laser radiation and causing the excited species to react chemically with a reaction partner. It may be necessary to supply additional energy to the reaction partner to make the chemical reaction possible. The method is applicable to the separation of hydrogen isotopes by the bromination of normal methanol in a mixture normal methanol and deuterated methanol; of uranium isotope by the reactions of UF 6 with SF 4 , SiCl 4 , HCl, or SO 2 ; and of boron isotopes by the reaction of BH 3 with NH 3

  8. Physical modeling and characterization of thermo-acoustic loudspeakers made of silver nano-wire films

    Science.gov (United States)

    La Torraca, P.; Larcher, L.; Bobinger, M.; Pavan, P.; Seeber, B.; Lugli, P.

    2017-06-01

    Recent developments of ultra-low heat capacity nanostructured materials revived the interest in the thermo-acoustic (TA) loudspeaker technology, which shows important advantages compared to the classical dynamic loudspeakers as they feature a lower cost and weight, flexibility, conformability to the surface of various shapes, and transparency. The development of the TA loudspeaker technology requires accurate physical models connecting the material properties to the thermal and acoustic speaker's performance. We present here a combined theoretical and experimental analysis of TA loudspeakers, where the electro-thermal and the thermo-acoustic transductions are handled separately, thus allowing an in-depth description of both the pressure and temperature dynamics. The electro-thermal transduction is analyzed by accounting for all the heat flow processes taking place between the TA loudspeaker and the surrounding environment, with focus on their frequency dependence. The thermo-acoustic conversion is studied by solving the coupled thermo-acoustic equations, derived from the Navier-Stokes equations, and by exploiting the Huygens-Fresnel principle to decompose the TA loudspeaker surface into a dense set of TA point sources. A general formulation of the 3D pressure field is derived summing up the TA point source contributions via a Rayleigh integral. The model is validated against temperature and sound pressure level measured on the TA loudspeaker sample made of a Silver Nanowire random network deposited on a polyimide substrate. A good agreement is found between measurements and simulations, demonstrating that the model is capable of connecting material properties to the thermo-acoustic performance of the device, thus providing a valuable tool for the design and optimization of TA loudspeakers.

  9. Thermoacoustic emission induced by deeply-penetrating radiation and its application to biomedical imaging

    International Nuclear Information System (INIS)

    Liew, Soo Chin.

    1989-01-01

    Thermoacoustic emissions induced by 2450 MHz microwave pulses in water, tissue-simulating phantoms and dog kidneys have been detected. The analytic signal magnitude has been employed in generating A-mode images with excellent depth resolution. Thermoacoustic emissions have also been detected from the dose-gradient at the beam edges of a 4 MeV x-ray beam in water. These results establish the feasibility of employing thermoacoustic signals in generating diagnostic images, and in locating x-ray beam edges during radiation therapy. A theoretical model for thermoacoustic imaging using a directional transducer has been developed, which may be used in the design of future thermoacoustic imaging system, and in facilitating comparisons with other types of imaging systems. A method of characterizing biological tissues has been proposed, which relates the power spectrum of the detected thermoacoustic signals to the autocorrelation function of the thermoacoustic source distribution in the tissues. The temperature dependence of acoustic signals induced by microwave pulses in water has been investigated. A microwave-induced thermoacoustic source capable of launching large aperture, unipolar ultrasonic plane wave pulses in water has been constructed

  10. Thermoacoustics of solids: A pathway to solid state engines and refrigerators

    Science.gov (United States)

    Hao, Haitian; Scalo, Carlo; Sen, Mihir; Semperlotti, Fabio

    2018-01-01

    Thermoacoustic oscillations have been one of the most exciting discoveries of the physics of fluids in the 19th century. Since its inception, scientists have formulated a comprehensive theoretical explanation of the basic phenomenon which has later found several practical applications to engineering devices. To date, all studies have concentrated on the thermoacoustics of fluid media where this fascinating mechanism was exclusively believed to exist. Our study shows theoretical and numerical evidence of the existence of thermoacoustic instabilities in solid media. Although the underlying physical mechanism exhibits some interesting similarities with its counterpart in fluids, the theoretical framework highlights relevant differences that have important implications on the ability to trigger and sustain the thermoacoustic response. This mechanism could pave the way to the development of highly robust and reliable solid-state thermoacoustic engines and refrigerators.

  11. Modeling of Multicomponent Mixture Separation Processes Using Hollow fiber Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sin-Ah; Kim, Jin-Kuk; Lee, Young Moo; Yeo, Yeong-Koo [Hanyang University, Seoul (Korea, Republic of)

    2015-02-15

    So far, most of research activities on modeling of membrane separation processes have been focused on binary feed mixture. But, in actual separation operations, binary feed is hard to find and most separation processes involve multicomponent feed mixture. In this work models for membrane separation processes treating multicomponent feed mixture are developed. Various model types are investigated and validity of proposed models are analysed based on experimental data obtained using hollowfiber membranes. The proposed separation models show quick convergence and exhibit good tracking performance.

  12. Sustainable New Brick and Thermo-Acoustic Insulation Panel from Mineralization of Stranded Driftwood Residues

    Directory of Open Access Journals (Sweden)

    Anna Laura Pisello

    2016-08-01

    Full Text Available There is considerable interest recently in by-products for application in green buildings. These materials are widely used as building envelope insulators or blocks. In this study, an experimental study was conducted to test stranded driftwood residues as raw material for possible thermo-acoustic insulation panel and environmentally sustainable brick. The thermal and acoustic characteristics of such a natural by-product were examined. Part of samples were mineralized by means of cement-based additive to reinforce the material and enhance its durability as well as fire resistance. Several mixtures with different sizes of ground wood chips and different quantities of cement were investigated. The thermo-acoustic in-lab characterization was aimed at investigating the thermal conductivity, thermal diffusivity, volumetric specific heat, and acoustic transmission loss. All samples were tested before and after mineralization. Results from this study indicate that it is possible to use stranded driftwood residues as building materials with competitive thermo-acoustic properties. In fact, the thermal conductivity was shown to be always around 0.07 W/mK in the unbound samples, and around double that value for the mineralized samples, which present a much higher volumetric specific heat (1.6 MJ/m3K and transmission loss capability. The lignin powder showed a sort of intermediate behavior between the unbound and the mineralized samples.

  13. Estimation of the minimum Prandtl number for binary gas mixtures formed with light helium and certain heavier gases: Application to thermoacoustic refrigerators

    International Nuclear Information System (INIS)

    Campo, Antonio; Papari, Mohammad M.; Abu-Nada, Eiyad

    2011-01-01

    This paper addresses a detailed procedure for the accurate estimation of low Prandtl numbers of selected binary gas mixtures. In this context, helium (He) is the light primary gas and the heavier secondary gases are nitrogen (N 2 ), oxygen (O 2 ), xenon (Xe), carbon dioxide (CO 2 ), methane (CH 4 ), tetrafluoromethane or carbon tetrafluoride (CF 4 ) and sulfur hexafluoride (SF 6 ). The three thermophysical properties forming the Prandtl number of binary gas mixtures Pr mix are heat capacity at constant pressure C p,mix (thermodynamic property), viscosity η mix (transport property) and thermal conductivity λ mix (transport property), which in general depend on temperature T and molar gas composition w. The precise formulas for the calculation of the trio C p,mix , η mix , and λ mix are gathered from various dependable sources. When the set of computed Pr mix values for the seven binary gas mixtures He + N 2 , He + O 2 , He + Xe, He + CO 2 , He + CH 4 , He + CF 4 , He + SF 6 at atmospheric conditions T = 300 K, p = 1 atm is plotted against the molar gas composition w on the w-domain [0,1], the family of Pr mix (w) curves exhibited distinctive concave shapes. In the curves format, all Pr mix (w) curves initiate with Pr ∼ 0.7 at w = 0 (associated with light primary He). Forthwith, each Pr mix (w) curve descends to a unique minimum and thereafter ascend back to Pr ∼ 0.7 at the terminal point w = 1 (connected to heavier secondary gases). Overall, it was found that among the seven binary gas mixtures tested, the He + Xe gas mixture delivered the absolute minimum Prandtl number Pr mix,min = 0.12 at the optimal molar gas composition w opt = 0.975. - Highlights: →Accurate estimation of low Prandtl numbers for some helium-based binary gas mixtures. →The thermophysical properties of the gases are calculated with precise formulas. →The absolute minimum Prandtl number is delivered by the He + Xe binary gas mixture. →Application to experimental thermoacoustic

  14. Evaluation of thermal efficiency and energy conversion of thermoacoustic Stirling engines

    International Nuclear Information System (INIS)

    Zhong Junhu; Zheng Yuli; Qing Li; Qiang Li

    2010-01-01

    Thermodynamic cycle transferring heat and work was executed in thermoacoustic engines, when the acoustic resonators substituted the moving mechanical components of the traditional heat engines. Based on the traveling-wave phasing and reversible heat transfer, thermoacoustic Stirling engines could achieve 70% of the Carnot efficiency theoretically, if the inevitable viscous dissipation in resonators was also counted as exported power. It should be pointed out an error on this efficiency evaluation in the previous literatures. More than 70% of the acoustic power production was often consumed by the side-branch resonator that was the essential configuration to build up a thermoacoustic Stirling engine. According to the simulation results and some experimental data, the actual available acoustic power consumed by the acoustic loads was restricted by the operating peak-to-mean pressure ratio, i.e. |p 1 /p m |. When the peak-to-mean pressure ratio operated on 4-6.5%, the thermal efficiency and power density of the available acoustic power reached higher levels. But the available acoustic power would approach zero when |p 1 /p m | attained 10%. It was approved that the turbulence oscillation occurred on the higher |p 1 /p m | (usually >4%) was the main reason of the excess dissipation in the side-branch resonator. This character of the available power limited the wide application of thermoacoustic Stirling engines. The evaluation of thermal efficiency and energy conversion also indicated the improving direction of thermoacoustic Stirling engines. Generators driven by the thermoacoustic Stirling engines were an effective way, due to the elimination of the side-branch resonator. To achieve a high power density and a high pressure ratio on the higher available power efficiency level, the standing-wave thermoacoustic engines might outvie the traveling-wave thermoacoustic engines. To enjoy the best features of standing-wave engines and traveling-wave engines simultaneously

  15. Review on the conversion of thermoacoustic power into electricity.

    Science.gov (United States)

    Timmer, Michael A G; de Blok, Kees; van der Meer, Theo H

    2018-02-01

    Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible areas of application, the conversion efficiency, maximum electrical power output and more generally the suggested focus for future work in the field.

  16. Study of molecular interactions in the mixtures of some primary alcohols with equimolar mixture of 1-propanol and alkylbenzoates at T = 303.15 K

    International Nuclear Information System (INIS)

    Sreehari Sastry, S.; Babu, Shaik; Vishwam, T.; Sie Tiong, Ha

    2014-01-01

    Highlights: • Study of molecular interactions between hydrogen bonded liquid mixtures of alcohols and alkylbenzoates. • Liquids mixtures of some primary alcohols with equimolar mixture of 1-propanol and alkylbenzoates are considered. • Speed of sound, density and viscosity are experimentally determined. • Excess values of different thermo-acoustic parameters are calculated and discussed. • Experimental and theoretical results are compared for speed of sound and viscosity models. -- Abstract: Speed of sound (U), density (ρ) and viscosity (η) values for the equimolar mixtures of (methyl benzoate + 1-propanol) and (ethyl benzoate + 1-propanol) with 1-butanol/1-pentanol including those of pure liquids were measured over the entire mole fraction range at T = 303.15 K. Using these experimentally determined values, various thermo-acoustic parameters such as excess isentropic compressibility (K s E ), excess molar volume (V E ) and excess free length (L f E ), excess Gibbs free energy (ΔG ∗E ) and excess enthalpy (H E ) have been calculated. The excess functions have been fitted to the Redlich–Kister type polynomial equation. The deviations for excess thermo-acoustic parameters have been explained on the basis of the intermolecular interactions present in these binary mixtures. The experimentally determined values of speed of sound have been used to check the applicability of different speed of sound models of Nomoto, Impedance relation, Van Dael and Vangeel, Junjie’s, free length theory and Rao’s relation. Viscosity results have been used to test the applicability of standard viscosity models of Grunberg–Nissan, Hind–Mc Laughlin, Katti–Chaudhary, Heric and Brewer, Frenkel and Tamura and Kurata at various temperatures for the binary liquid systems under study

  17. Theoretical and experimental study of thermoacoustic engines

    Science.gov (United States)

    Raspet, Richard; Bass, Henry E.; Arnott, W. P.

    1992-12-01

    A three year study of thermoacoustic engines operating as prime movers and refrigerators was completed. The major thrust of this effort was the use and theoretical description of ceramic honeycomb structures as the active element in thermoacoustic engines. An air-filled demonstration prime mover was constructed and demonstrated at Acoustical Society of America and IEE meetings. A helium-filled test prime mover was designed and built an is being employed in studies of the threshold of oscillation as a function of temperature difference and pressure. In addition, acoustically based theories of the thermoacoustic engine have been developed and tested for a parallel plate stack at the Naval Postgraduate School and for a honeycomb stack at the University of Mississippi. Most of this work is described in detail in the attached publications. In this report we will give an overview of the research completed to date and its relationship to work performed at the Naval Postgraduate School and to future work at the University of Mississippi.

  18. Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

    Directory of Open Access Journals (Sweden)

    E. V. Blagin

    2014-01-01

    Full Text Available The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented.

  19. The separation of solid and liquid components of mixtures

    International Nuclear Information System (INIS)

    Hunter, W.M.

    1980-01-01

    An improved method of separating solid and liquid components of mixtures is described which is particularly suited for use in automated radioimmunoassay systems in the analysis of bound and free fractions. A second liquid, having a density intermediate between those of the solid and liquid components, is delivered to the solid/ liquid mixture to form a discrete layer below the mixture and the solid separates into this lower liquid layer assisted by centrifugal force. The second liquid of intermediate density is an aqueous solution of a highly hydrophilic and electrically non-polar solute, such as an aqueous sucrose solution. Further liquids of intermediate density and progressively higher density may be delivered to form further discrete layers below the initial layer of the second dense liquid. After separation of the solid and liquid components of the mixture, the supernatant liquid component of the original mixture is removed in a controlled and non-turbulent manner. The method is illustrated in radioimmunoassays for platelet β-thromboglobulin and human follicle stimulating hormone. (U.K.)

  20. Design of numerical model for thermoacoustic devices using OpenFOAM

    Science.gov (United States)

    Tisovsky, Tomas; Vit, Tomas

    2017-09-01

    Thermoacoustic devices are increasingly popular especially because of their construction simplicity and the ability to easily convert waste heat into the form of usable energy. Aim of this paper is to introduce some of the effective procedures for creating a complex mathematical model of thermoacoustic devices in OpenFOAM.

  1. Mathematical Modeling of Nonstationary Separation Processes in Gas Centrifuge Cascade for Separation of Multicomponent Isotope Mixtures

    Directory of Open Access Journals (Sweden)

    Orlov Alexey

    2016-01-01

    Full Text Available This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge cascades for separation of multicomponent isotope mixtures.

  2. Thermoacoustic engines and refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.

    1996-12-31

    This report is a transcript of a practice lecture given in preparation for a review lecture on the operation of thermoacoustic engines and refrigerators. The author begins by a brief review of the thermodynamic principles underlying the operation of thermoacoustic engines and refrigerators. Remember from thermodynamics class that there are two kinds of heat engines, the heat engine or the prime mover which produces work from heat, and the refrigerator or heat pump that uses work to pump heat. The device operates between two thermal reservoirs at temperatures T{sub hot} and T{sub cold}. In the heat engine, heat flows into the device from the reservoir at T{sub hot}, produces work, and delivers waste heat into the reservoir at T{sub cold}. In the refrigerator, work flows into the device, lifting heat Q{sub cold} from reservoir at T{sub cold} and rejecting waste heat into the reservoir at T{sub hot}.

  3. TH-AB-209-09: Quantitative Imaging of Electrical Conductivity by VHF-Induced Thermoacoustics

    Energy Technology Data Exchange (ETDEWEB)

    Patch, S; Hull, D [Avero Diagnostics, Irving, TX (United States); See, W [Medical College of Wisconsin, Milwaukee, WI (United States); Hanson, G [UW-Milwaukee, Milwaukee, WI (United States)

    2016-06-15

    Purpose: To demonstrate that very high frequency (VHF) induced thermoacoustics has the potential to provide quantitative images of electrical conductivity in Siemens/meter, much as shear wave elastography provides tissue stiffness in kPa. Quantitatively imaging a large organ requires exciting thermoacoustic pulses throughout the volume and broadband detection of those pulses because tomographic image reconstruction preserves frequency content. Applying the half-wavelength limit to a 200-micron inclusion inside a 7.5 cm diameter organ requires measurement sensitivity to frequencies ranging from 4 MHz down to 10 kHz, respectively. VHF irradiation provides superior depth penetration over near infrared used in photoacoustics. Additionally, VHF signal production is proportional to electrical conductivity, and prostate cancer is known to suppress electrical conductivity of prostatic fluid. Methods: A dual-transducer system utilizing a P4-1 array connected to a Verasonics V1 system augmented by a lower frequency focused single element transducer was developed. Simultaneous acquisition of VHF-induced thermoacoustic pulses by both transducers enabled comparison of transducer performance. Data from the clinical array generated a stack of 96-images with separation of 0.3 mm, whereas the single element transducer imaged only in a single plane. In-plane resolution and quantitative accuracy were measured at isocenter. Results: The array provided volumetric imaging capability with superior resolution whereas the single element transducer provided superior quantitative accuracy. Combining axial images from both transducers preserved resolution of the P4-1 array and improved image contrast. Neither transducer was sensitive to frequencies below 50 kHz, resulting in a DC offset and low-frequency shading over fields of view exceeding 15 mm. Fresh human prostates were imaged ex vivo and volumetric reconstructions reveal structures rarely seen in diagnostic images. Conclusion

  4. Gas-chromatographic separation of hydrogen isotopic mixtures

    International Nuclear Information System (INIS)

    Preda, Anisoara; Bidica, Nicolae

    2005-01-01

    Full text: Gas chromatographic separation of hydrogen isotopes have been reported in the literature since late of 1950's. Gas chromatography is primarily an analytical method, but because of its properties it may be used in many other fields with excellent results. A simple method is proposed for the gas-chromatographic analysis of complex gas mixtures containing hydrogen isotopes; the method is based on the substantial difference in the thermal conductivity of these isotopes. One of the main disadvantages of the conventional gas chromatography is the long retention times required for the analysis of hydrogen gas mixtures while the column is operated at very low temperature. The method described in this paper was based on using a capillary molecular sieve 5A column operated for this kind of separation at 173 K. The carrier gas was Ne and the detector was TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. (authors)

  5. Forced synchronization and asynchronous quenching in a thermo-acoustic system

    Science.gov (United States)

    Mondal, Sirshendu; Pawar, Samadhan A.; Sujith, Raman

    2017-11-01

    Forced synchronization, which has been extensively studied in theory and experiments, occurs through two different mechanisms known as phase locking and asynchronous quenching. The latter indicates the suppression of oscillation amplitude. In most practical combustion systems such as gas turbine engines, the main concern is high amplitude pressure oscillations, known as thermo-acoustic instability. Thermo-acoustic instability is undesirable and needs to be suppressed because of its damaging consequences to an engine. In the present study, a systematic experimental investigation of forced synchronization is performed in a prototypical thermo-acoustic system, a Rijke tube, in its limit cycle operation. Further, we show a qualitatively similar behavior using a reduced order model. In the phase locking region, the simultaneous occurrence of synchronization and resonant amplification leads to high amplitude pressure oscillations. However, a reduction in the amplitude of natural oscillations by about 78% of the unforced amplitude is observed when the forcing frequency is far lower than the natural frequency. This shows the possibility of suppression of the oscillation amplitude through asynchronous quenching in thermo-acoustic systems.

  6. Acoustic field characteristics and performance analysis of a looped travelling-wave thermoacoustic refrigerator

    International Nuclear Information System (INIS)

    Jin, T.; Yang, R.; Wang, Y.; Feng, Y.; Tang, K.

    2016-01-01

    Highlights: • Key issues for a highly efficient thermoacoustic conversion are analyzed. • A looped thermoacoustic refrigerator with one engine stage and one refrigerator stage is proposed. • Effective refrigeration powered by heat sources below 250 °C is demonstrated in the simulation. • Impact of cooling/heating temperatures on system performance is analyzed in view of acoustic field. - Abstract: This paper focuses on a looped travelling-wave thermoacoustic refrigerator powered by thermal energy. Based on a simplified model for the regenerator, key issues for a highly efficient thermoacoustic conversion, including both thermal-to-acoustic and heat-pumping processes, are summarized. A looped travelling-wave thermoacoustic refrigerator with one engine stage and one refrigerator stage is proposed, with emphasis on high normalized acoustic impedance, sufficient volumetric velocity and appropriate phase relation close to travelling wave in the regenerators of both engine and refrigerator. Simulation results indicate that for the ambient temperature of 30 °C, the looped travelling-wave thermoacoustic refrigerator can be powered by the heat at 210–250 °C to achieve the refrigeration at −3 °C with the overall coefficient of performance above 0.4 and the relative Carnot coefficient of performance over 13%. The characteristics of the acoustic field inside the loop configuration are analyzed in detail to reveal the operation mechanism of the looped travelling-wave thermoacoustic refrigerator. Additional analyses are conducted on the impact of the cooling and the heating temperatures, which are of great concern to the refrigeration applications and the utilization of low-grade thermal energy.

  7. Open-loop control of quasiperiodic thermoacoustic oscillations

    Science.gov (United States)

    Guan, Yu; Gupta, Vikrant; Kashinath, Karthik; Li, Larry K. B.

    2017-11-01

    The open-loop application of periodic acoustic forcing has been shown to be a potentially effective strategy for controlling periodic thermoacoustic oscillations, but its effectiveness on aperiodic thermoacoustic oscillations is less clear. In this experimental study, we apply periodic acoustic forcing to a ducted premixed flame oscillating quasiperiodically at two incommensurate natural frequencies, f1 and f2. We find that (i) above a critical forcing amplitude, the system locks into the forcing by oscillating only at the forcing frequency ff, producing a closed periodic orbit in phase space with no evidence of the original T2 torus attractor; (ii) the critical forcing amplitude required for lock-in decreases as ff approaches either f1 or f2, resulting in characteristic ∨-shaped lock-in boundaries around the two natural modes; and (iii) for a wide range of forcing frequencies, the system's oscillation amplitude can be reduced to less than 20% of that of the unforced system. These findings show that the open-loop application of periodic acoustic forcing can be an effective strategy for controlling aperiodic thermoacoustic oscillations. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

  8. A multi-stage traveling-wave thermoacoustically-driven refrigeration system operating at liquefied natural gas temperature

    Science.gov (United States)

    Luo, K.; Sun, D. M.; Zhang, J.; Shen, Q.; Zhang, N.

    2017-12-01

    This study proposes a multi-stage travelling-wave thermoacoustically refrigeration system (TAD-RS) operating at liquefied natural gas temperature, which consists of two thermoacoustic engines (TAE) and one thermoacoustic refrigerator (TAR) in a closed-loop configuration. Three thermoacoustic units connect each other through a resonance tube of small cross-sectional area, achieving “self-matching” for efficient thermoacoustic conversion. Based on the linear thermoacoustic theory, a model of the proposed system has been built by using DeltaEC program to show the acoustic field characteristics and performance. It is shown that with pressurized 5 MPa helium as working gas, the TAEs are able to build a stable and strong acoustic field with a frequency of about 85 Hz. When hot end temperature reaches 923 K, this system can provide about 1410 W cooling power at 110 K with an overall exergy efficiency of 15.5%. This study indicates a great application prospect of TAD-RS in the field of natural gas liquefaction with a large cooling capacity and simple structure.

  9. Performance measurement of a mini thermoacoustic refrigerator and associated drivers

    OpenAIRE

    Petrina, Denys E.

    2002-01-01

    Approved for public release; distribution is unlimited A miniature Thermoacoustic refrigerator is being developed to cool integrated circuits - which must sometimes operate at high temperatures nearing the upper threshold of their tolerance - to temperature spans more within the circuits' tolerable limits, without the need of the chemicals of a traditional refrigerating system. The development of an electrically powered acoustic driver that powers the thermoacoustic refrigerator is describ...

  10. A Thermoacoustic Model for High Aspect Ratio Nanostructures

    Directory of Open Access Journals (Sweden)

    Masoud S. Loeian

    2016-09-01

    Full Text Available In this paper, we have developed a new thermoacoustic model for predicting the resonance frequency and quality factors of one-dimensional (1D nanoresonators. Considering a nanoresonator as a fix-free Bernoulli-Euler cantilever, an analytical model has been developed to show the influence of material and geometrical properties of 1D nanoresonators on their mechanical response without any damping. Diameter and elastic modulus have a direct relationship and length has an inverse relationship on the strain energy and stress at the clamp end of the nanoresonator. A thermoacoustic multiphysics COMSOL model has been elaborated to simulate the frequency response of vibrating 1D nanoresonators in air. The results are an excellent match with experimental data from independently published literature reports, and the results of this model are consistent with the analytical model. Considering the air and thermal damping in the thermoacoustic model, the quality factor of a nanowire has been estimated and the results show that zinc oxide (ZnO and silver-gallium (Ag2Ga nanoresonators are potential candidates as nanoresonators, nanoactuators, and for scanning probe microscopy applications.

  11. Exergetic optimization of a thermoacoustic engine using the particle swarm optimization method

    International Nuclear Information System (INIS)

    Chaitou, Hussein; Nika, Philippe

    2012-01-01

    Highlights: ► Optimization of a thermoacoustic engine using the particle swarm optimization method. ► Exergetic efficiency, acoustic power and their product are the optimized functions. ► PSO method is used successfully for the first time in the TA research. ► The powerful PSO tool is advised to be more involved in the TA research and design. ► EE times AP optimized function is highly recommended to design any new TA devices. - Abstract: Thermoacoustic engines convert heat energy into acoustic energy. Then, the acoustic energy can be used to pump heat or to generate electricity. It is well-known that the acoustic energy and therefore the exergetic efficiency depend on parameters such as the stack’s hydraulic radius, the stack’s position in the resonator and the traveling–standing-wave ratio. In this paper, these three parameters are investigated in order to study and analyze the best value of the produced acoustic energy, the exergetic efficiency and the product of the acoustic energy by the exergetic efficiency of a thermoacoustic engine with a parallel-plate stack. The dimensionless expressions of the thermoacoustic equations are derived and calculated. Then, the Particle Swarm Optimization method (PSO) is introduced and used for the first time in the thermoacoustic research. The use of the PSO method and the optimization of the acoustic energy multiplied by the exergetic efficiency are novel contributions to this domain of research. This paper discusses some significant conclusions which are useful for the design of new thermoacoustic engines.

  12. Control of thermoacoustic instability with a drum-like silencer

    Science.gov (United States)

    Zhang, Guangyu; Wang, Xiaoyu; Li, Lei; Jing, Xiaodong; Sun, Xiaofeng

    2017-10-01

    Theoretical investigation is carried out by a novel method of controlling thermoacoustic instability with a drum-like silencer. It is shown that by decreasing the frequency of thermoacoustic system, the instability can be suppressed with the help of drum-like silencer. The purely reactive silencer, which is composed of a flexible membrane and a backing cavity, is usually known as a noise control device that works effectively in low frequency bandwidth without any aerodynamic loss. In present research, the silencer is exploited in a Rijke tube, as a means of decreasing the natural frequency of the system, and consequently changing the resonance period of the system. The "transfer element method" (TEM) is used to consider the interactions between the acoustic waves and the flexible membranes of the silencer. The effects of all possible properties of the silencer on the growth rate and resonance frequency of the thermoacoustic system are explored. According to the calculation results, it is found that for some properties of the silencer, the resonance frequencies are greatly decreased and then the phase difference between the unsteady heat release and the pressure fluctuation is increased. Consequently, the instability is suppressed with some dissipation that can not be able to control its onset in the original system. Therefore, when the damping is low, but not zero, it is effective to control thermoacoustic instability with this technique.

  13. A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers.

    Science.gov (United States)

    de Jong, J A; Wijnant, Y H; de Boer, A

    2014-03-01

    A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic systems. The model is implementable in existing (quasi-)1D thermoacoustic codes, such as DeltaEC. Examples of generated results show good agreement with literature results. The model allows for arbitrary wave phasing; however, it is shown that the wave phasing does not significantly influence the heat transfer.

  14. Development of a 3 kW double-acting thermoacoustic Stirling electric generator

    International Nuclear Information System (INIS)

    Wu, Zhanghua; Yu, Guoyao; Zhang, Limin; Dai, Wei; Luo, Ercang

    2014-01-01

    Highlights: • A 3 kW double-acting thermoacoustic Stirling electric generator is introduced. • 1.57 kW electric power with 16.8% thermal-to-electric efficiency was achieved. • High mechanical damping coefficient greatly decreases the system performance. • Performance difference is significant, which also decreased system performance. - Abstract: In this paper, a double-acting thermoacoustic Stirling electric generator is proposed as a new device capable of converting external heat into electric power. In the system, at least three thermoacoustic Stirling heat engines and three linear alternators are used to build a multiple-cylinder electricity generator. In comparison with the conventional thermoacoustic electricity generation system, the double-acting thermoacoustic Stirling electric generator has advantages on efficiency, power density and power capacity. In order to verify the idea, a prototype of 3 kW three-cylinder double-acting thermoacoustic Stirling electric generator is designed, built and tested. Based on the classic thermoacoustic theory, numerical simulation is performed to obtain the thermodynamic parameters of the engine. And distributions of key parameters are presented for a better understanding of the energy conversion process in the engine. In the experiments, a maximum electric power of about 1.57 kW and a maximum thermal-to-electric conversion efficiency of 16.8% were achieved with 5 MPa pressurized helium and 86 Hz working frequency. However, we find that the mechanical damping coefficient of the piston is dramatically increased due to the deformation of the cylinder wall caused by high thermal stress during the experiments. Thereby, the system performance was greatly reduced. Additionally, the performance differences between three engines and three alternators are significant, such as the heating temperature difference between three heater blocks of the engines, the piston displacement and the output electric power differences between

  15. A hot air driven thermoacoustic-Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, M.E.H.; Spoelstra, S. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-09-15

    Significant energy savings can be obtained by implementing a thermally driven heat pump into industrial or domestic applications. Such a thermally driven heat pump uses heat from a high-temperature source to drive the system which upgrades an abundantly available heat source (industrial waste heat, air, water, geothermal). A way to do this is by coupling a thermoacoustic engine with a thermoacoustic heat pump. The engine is driven by a burner and produces acoustic power and heat at the required temperature. The acoustic power is used to pump heat in the heat pump to the required temperature. This system is attractive since it uses a noble gas as working medium and has no moving mechanical parts. This paper deals with the first part of this system: the engine. In this study, hot air is used to simulate the flue gases originating from a gas burner. This is in contrast with a lot of other studies of thermoacoustic engines that use an electrical heater as heat source. Using hot air resembles to a larger extent the real world application. The engine produces about 300W of acoustic power with a performance of 41% of the Carnot efficiency at a hot air temperature of 620C.

  16. A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers

    NARCIS (Netherlands)

    de Jong, Anne; Wijnant, Ysbrand H.; de Boer, Andries

    2014-01-01

    A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic

  17. Thermoacoustic Emission Induced by Deeply-Penetrating Radiation and its Application to Biomedical Imaging.

    Science.gov (United States)

    Liew, Soo Chin

    Thermoacoustic emissions induced by 2450 MHz microwave pulses in water, tissue-simulating phantoms and dog kidneys have been detected. The analytic signal magnitude has been employed in generating 'A-mode' images with excellent depth resolution. Thermoacoustic emissions have also been detected from the dose-gradient at the beam edges of a 4 MeV x-ray beam in water. These results establish the feasibility of employing thermoacoustic signals in generating diagnostic images, and in locating x-ray beam edges during radiation therapy. A theoretical model for thermoacoustic imaging using a directional transducer has been developed, which may be used in the design of future thermoacoustic imaging system, and in facilitating comparisons with other types of imaging systems. A method of characterizing biological tissues has been proposed, which relates the power spectrum of the detected thermoacoustic signals to the autocorrelation function of the thermoacoustic source distribution in the tissues. The temperature dependence of acoustic signals induced by microwave pulses in water has been investigated. The signal amplitudes vary with temperature as the thermal expansion of water, except near 4^circ C. The signal waveforms show a gradual phase change as the temperature changes from below 4^ circ to above 4^circ C. This anomaly is due to the presence of a nonthermal component detected near 4^circC, whose waveform is similar to the derivative of the room temperature signal. The results are compared to a model based on a nonequilibrium relaxation mechanism proposed by Pierce and Hsieh. The relaxation time was found to be (0.20 +/- 0.02) ns and (0.13 +/- 0.02) ns for 200 ns and 400 ns microwave pulse widths, respectively. A microwave-induced thermoacoustic source capable of launching large aperture, unipolar ultrasonic plane wave pulses in water has been constructed. This source consists of a thin water layer trapped between two dielectric media. Due to the large mismatch in the

  18. The feasibility of using microwave-induced thermoacoustic tomography for detection and evaluation of renal calculi

    International Nuclear Information System (INIS)

    Cao Caijun; Nie Liming; Lou Cunguang; Xing Da

    2010-01-01

    Imaging of renal calculi is important for patients who suffered a urinary calculus prior to treatment. The available imaging techniques include plain x-ray, ultrasound scan, intravenous urogram, computed tomography, etc. However, the visualization of a uric acid calculus (radiolucent calculi) is difficult and often impossible by the above imaging methods. In this paper, a new detection method based on microwave-induced thermoacoustic tomography was developed to detect the renal calculi. Thermoacoustic images of calcium oxalate and uric acid calculus were compared with their x-ray images. The microwave absorption differences among the calcium oxalate calculus, uric acid calculus and normal kidney tissue could be evaluated by the amplitude of the thermoacoustic signals. The calculi hidden in the swine kidney were clearly imaged with excellent contrast and resolution in the three orthogonal thermoacoustic images. The results indicate that thermoacoustic imaging may be developed as a complementary method for detecting renal calculi, and its low cost and effective feature shows high potential for clinical applications.

  19. Experimental Investigation of Bifurcations in a Thermoacoustic Engine

    Directory of Open Access Journals (Sweden)

    Vishnu R. Unni

    2015-06-01

    Full Text Available In this study, variation in the characteristics of the pressure oscillations in a thermoacoustic engine is explored as the input heat flux is varied. A bifurcation diagram is plotted to study the variation in the qualitative behavior of the acoustic oscillations as the input heat flux changes. At a critical input heat flux (60 Watt, the engine begins to produce acoustic oscillations in its fundamental longitudinal mode. As the input heat flux is increased, incommensurate frequencies appear in the power spectrum. The simultaneous presence of incommensurate frequencies results in quasiperiodic oscillations. On further increase of heat flux, the fundamental mode disappears and second mode oscillations are observed. These bifurcations in the characteristics of the pressure oscillations are the result of nonlinear interaction between multiple modes present in the thermoacoustic engine. Hysteresis in the bifurcation diagram suggests that the bifurcation is subcritical. Further, the qualitative analysis of different dynamic regimes is performed using nonlinear time series analysis. The physical reason for the observed nonlinear behavior is discussed. Suggestions to avert the variations in qualitative behavior of the pressure oscillations in thermoacoustic engines are also provided.

  20. Separation of azeotropic mixtures : tools for analysis and studies on batch distillation operation

    OpenAIRE

    Hilmen, Eva-Katrine

    2000-01-01

    Separation of azeotropic mixtures is a topic of great practical and industrial interest. Most liquid mixtures of organic components form nonideal systems. The presence of some specific groups, particularly polar groups (oxygen, nitrogen, chlorine and fluorine), often results in the formation of azeotropes. Azeotropic mixtures may often be effectively separated by distillation by adding a liquid material (entrainer) to the system. For the development of separation processes for azeotropic ...

  1. Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

    International Nuclear Information System (INIS)

    Ogunlade, Olumide; Beard, Paul

    2015-01-01

    Purpose: Thermoacoustic imaging at microwave excitation frequencies is limited by the low differential contrast exhibited by high water content tissues. To overcome this, exogenous thermoacoustic contrast agents based on gadolinium compounds, iron oxide, and single wall carbon nanotubes have previously been suggested and investigated. However, these previous studies did not fully characterize the electric, magnetic, and thermodynamic properties of these agents thus precluding identification of the underlying sources of contrast. To address this, measurements of the complex permittivity, complex permeability, DC conductivity, and Grüneisen parameter have been made. These measurements allowed the origins of the contrast provided by each substance to be identified. Methods: The electric and magnetic properties of the contrast agents were characterized at 3 GHz using two rectangular waveguide cavities. The DC conductivity was measured separately using a conductivity meter. Thermoacoustic signals were then acquired and compared to those generated in water. Finally, 3D electromagnetic simulations were used to decouple the different contributions to the absorbed power density. Results: It was found that the gadolinium compounds provided appreciable electric contrast but not originating from the gadolinium itself. The contrast was either due to dissociation of the gadolinium salt which increased ionic conductivity or its nondissociated polar fraction which increased dielectric polarization loss or a combination of both. In addition, very high concentrations were required to achieve appreciable contrast, to the extent that the Grüneisen parameter increased significantly and became a source of contrast. Iron oxide particles were found to produce low but measurable dielectric contrast due to dielectric polarization loss, but this is attributed to the coating of the particles not the iron oxide. Single wall carbon nanotubes did not provide measurable contrast of any type

  2. Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

    Energy Technology Data Exchange (ETDEWEB)

    Ogunlade, Olumide, E-mail: o.ogunlade@ucl.ac.uk; Beard, Paul [Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT (United Kingdom)

    2015-01-15

    Purpose: Thermoacoustic imaging at microwave excitation frequencies is limited by the low differential contrast exhibited by high water content tissues. To overcome this, exogenous thermoacoustic contrast agents based on gadolinium compounds, iron oxide, and single wall carbon nanotubes have previously been suggested and investigated. However, these previous studies did not fully characterize the electric, magnetic, and thermodynamic properties of these agents thus precluding identification of the underlying sources of contrast. To address this, measurements of the complex permittivity, complex permeability, DC conductivity, and Grüneisen parameter have been made. These measurements allowed the origins of the contrast provided by each substance to be identified. Methods: The electric and magnetic properties of the contrast agents were characterized at 3 GHz using two rectangular waveguide cavities. The DC conductivity was measured separately using a conductivity meter. Thermoacoustic signals were then acquired and compared to those generated in water. Finally, 3D electromagnetic simulations were used to decouple the different contributions to the absorbed power density. Results: It was found that the gadolinium compounds provided appreciable electric contrast but not originating from the gadolinium itself. The contrast was either due to dissociation of the gadolinium salt which increased ionic conductivity or its nondissociated polar fraction which increased dielectric polarization loss or a combination of both. In addition, very high concentrations were required to achieve appreciable contrast, to the extent that the Grüneisen parameter increased significantly and became a source of contrast. Iron oxide particles were found to produce low but measurable dielectric contrast due to dielectric polarization loss, but this is attributed to the coating of the particles not the iron oxide. Single wall carbon nanotubes did not provide measurable contrast of any type

  3. Modeling of micro-scale thermoacoustics

    Energy Technology Data Exchange (ETDEWEB)

    Offner, Avshalom [The Nancy and Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Department of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Ramon, Guy Z., E-mail: ramong@technion.ac.il [Department of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2016-05-02

    Thermoacoustic phenomena, that is, onset of self-sustained oscillations or time-averaged fluxes in a sound wave, may be harnessed as efficient and robust heat transfer devices. Specifically, miniaturization of such devices holds great promise for cooling of electronics. At the required small dimensions, it is expected that non-negligible slip effects exist at the solid surface of the “stack”-a porous matrix, which is used for maintaining the correct temporal phasing of the heat transfer between the solid and oscillating gas. Here, we develop theoretical models for thermoacoustic engines and heat pumps that account for slip, within the standing-wave approximation. Stability curves for engines with both no-slip and slip boundary conditions were calculated; the slip boundary condition curve exhibits a lower temperature difference compared with the no slip curve for resonance frequencies that characterize micro-scale devices. Maximum achievable temperature differences across the stack of a heat pump were also calculated. For this case, slip conditions are detrimental and such a heat pump would maintain a lower temperature difference compared to larger devices, where slip effects are negligible.

  4. Modeling of micro-scale thermoacoustics

    International Nuclear Information System (INIS)

    Offner, Avshalom; Ramon, Guy Z.

    2016-01-01

    Thermoacoustic phenomena, that is, onset of self-sustained oscillations or time-averaged fluxes in a sound wave, may be harnessed as efficient and robust heat transfer devices. Specifically, miniaturization of such devices holds great promise for cooling of electronics. At the required small dimensions, it is expected that non-negligible slip effects exist at the solid surface of the “stack”-a porous matrix, which is used for maintaining the correct temporal phasing of the heat transfer between the solid and oscillating gas. Here, we develop theoretical models for thermoacoustic engines and heat pumps that account for slip, within the standing-wave approximation. Stability curves for engines with both no-slip and slip boundary conditions were calculated; the slip boundary condition curve exhibits a lower temperature difference compared with the no slip curve for resonance frequencies that characterize micro-scale devices. Maximum achievable temperature differences across the stack of a heat pump were also calculated. For this case, slip conditions are detrimental and such a heat pump would maintain a lower temperature difference compared to larger devices, where slip effects are negligible.

  5. Separating Iso-Propanol-Toluene mixture by azeotropic distillation

    Science.gov (United States)

    Iqbal, Asma; Ahmad, Syed Akhlaq

    2018-05-01

    The separation of Iso-Propanol-Toluene azeotropic mixture using Acetone as an entrainer has been simulated on Aspen Plus software package using rigorous methods. Calculations of the vapor-liquid equilibrium for the binary system are done using UNIQUAC-RK model which gives a good agreement with the experimental data reported in literature. The effects of the Reflux ratio (RR), distillate-to-feed molar ratio (D/F), feed stage, solvent feed stage, Total no. of stages and solvent feed temperature on the product purities and recoveries are studied to obtain their optimum values that give the maximum purity and recovery of products. The configuration consists of 20 theoretical stages with an equimolar feed of binary mixture. The desired separation of binary mixture has been achieved at the feed stage and an entrainer feeding stage of 15 and 12 respectively with the reflux ratios of 2.5 and 4.0, and D/F ratio of 0.75 and 0.54 respectively in the two columns. The simulation results thus obtained are useful to setup the optimal column configuration of the azeotropic distillation process.

  6. Thermoacoustic refrigerators : experiments and scaling analysis

    NARCIS (Netherlands)

    Li, Y.

    2011-01-01

    Thermoacoustics, as the word spelling indicates, is an interdisciplinary field in physics. Both acoustics and thermodynamics are involved in the description of this interesting phenomenon. When a solid wall is present in direction of the wave vector of an acoustic field, the interaction between the

  7. Mean temperature profile at the entrance of a thermoacoustic stacked screen heat exchanger

    NARCIS (Netherlands)

    Bühler, Simon; wilcox, D; Oosterhuis, Joris; van der Meer, Theodorus H.

    2015-01-01

    In thermoacoustic devises, the thermoacoustic e ect occurs in the regenerator placed between two heat exchangers. The entrance e ects of such heat exchanger are investigated with two computational uid dynamics (CFD) test cases. The rst CFD test case models an ideal heat exchanger adjacent to an open

  8. Vertical vs Lateral Macrophase Separation in Thin Films of Block Copolymer Mixtures

    DEFF Research Database (Denmark)

    Berezkin, Anatoly V.; Jung, Florian; Posselt, Dorthe

    2017-01-01

    Mixtures of two diblock copolymers of very different lengths may feature both macro- and microphase separation; however, not much is known about the mechanisms of separation in diblock copolymer thin films. In the present work, we study thin films of mixtures of two compositionally symmetric bloc...

  9. Thermo-Acoustic Convertor for Space Power, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Sunpower will introduce thermoacoustic Stirling heat engine (TASHE) technology into its existing Stirling convertor technology to eliminate the moving mechanical...

  10. Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

    KAUST Repository

    Pan, Yichang

    2012-02-01

    The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed excellent separation performances for a wide range of propylene/propane mixtures. The membrane showed a permeability of propylene up to 200. barrers and a propylene to propane separation factor up to 50 at optimal separation conditions, well surpassing the "upper-bound trade-off" lines of existing polymer and carbon membranes. The experimental data also showed that the membranes had excellent reproducibility, long-term stability and thermal stability. © 2011 Elsevier B.V.

  11. Numerical analysis on a four-stage looped thermoacoustic Stirling power generator for low temperature waste heat

    International Nuclear Information System (INIS)

    Wang, Kai; Qiu, Limin

    2017-01-01

    Highlights: • Four-stage looped thermoacoustic power generator for waste heat is studied. • Coupling position is found to have remarkable effects on performance. • Better efficiency is available when coupled near the cold ends of the cores. • The influence of the regenerator position on the efficiency is weak. • Matching between the acoustic impedances of engine and alternator is important. - Abstract: Recent developments in thermoacoustic technologies have demonstrated that multi-stage looped thermoacoustic Stirling engine would be a promising option for harvesting waste heat. Previous studies on multi-stage looped thermoacoustic systems were mainly focused on heat-driven refrigeration or heat pumping, while much fewer work were done on power generations, especially those for recovering low temperature heat. In this work, a four-stage looped thermoacoustic Stirling power generator for generating electricity from low temperature waste heat at 300 °C is systematically studied. A numerical model is built and then validated on an experimental four-stage looped thermoacoustic Stirling engine. On the basis of the validated model, the effects of the coupling position for the linear alternators and the regenerator position on the acoustic characteristics and performances of the power generation system are numerically investigated. The distributions of the acoustic fields along the loop, including the pressure amplitude, volume flow rate, phase angle, specific acoustic impedance and acoustic power, are presented and analysed for three representative coupling modes. Superior efficiency is achieved when the linear alternators are coupled near the cold ends of the thermoacoustic cores on the resonators, while more electric power is generated at the hot ends. The worst performance is expected when the linear alternators are connected at the middle of the resonators. The underling mechanisms are further explained detailedly by analysing the characteristics of the

  12. Initial density fluctuations effects on the microphase separation in ramified polymer mixture

    Energy Technology Data Exchange (ETDEWEB)

    Ghaouar, N. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire 2092 (Tunisia) and Institut National des Sciences Appliquees et de Technologie, INSAT, Centre Urbain Nord, BP. 676, Tunis (Tunisia)]. E-mail: naoufel-ghaouar@lycos.com

    2007-02-19

    Our study focuses on the initial density fluctuations effects on microphase separation in ramified polymer mixture. For this purpose, we introduce a screening length {kappa} by considering the condition that the scattered intensity should not be changed by cross-linking. We recover that {kappa}{sup 2}{approx}C/({chi}-{chi}{sub i}), where C is the rigidity constant of the network and {chi} the Flory parameter. Three regimes versus the temperature of the mixture are discussed. The kinetics of the microphase separation is also studied through the relaxation rate. The derived relaxation rate evolution relative to ramified polymers mixture must be compared to that relative to a linear polymer mixture. Finally, we discuss the solvent effect on the microphase separation and we show that the initial fluctuations have little importance because of the excluded volume interaction.

  13. Nonorthogonality analysis of a thermoacoustic system with a premixed V-shaped flame

    International Nuclear Information System (INIS)

    Ji, Chenzhen; Zhao, Dan; Li, Xinyan; Li, Shihuai; Li, Junwei

    2014-01-01

    Highlights: • Nonorthogonality analysis of a choked thermoacoustic system is conducted. • A thermoacoustic model of a premixed V-shaped flame is developed. • Nonorthogonality is identified to arise from the boundary condition and the flame. • The contribution from the flame is shown to play a dominant role. • Eigenmodes nonorthogonality leads to transient growth of acoustic disturbances. - Abstract: Thermoacoustic instability occurs in many combustion systems, such as aero-engine afterburners, rocket motors, ramjets and gas turbines. It most often arises due to the coupling between unsteady heat release and acoustic waves. In this work, nonorthogonality analysis of a choked combustor with a gutter confined is conducted. Such configuration is used as a simplified model of the afterburner of an aero-engine. A thermoacoustic model is developed first to study the nonnormal interaction between acoustic disturbances and a premixed V-shaped flame anchored to the tip of the gutter. Eigenmode nonorthogonality analysis is then conducted. The thermoacoustic system is shown to be nonnormal and characterized by nonorthogonal eigenmodes. The nonorthogonality is identified to arise from both the complex boundary condition and the monopole-like flame. However, the contribution from the Robin-type boundary is approximately 1.5% of that from the flame. Thus the flame is identified to play a dominant role. One practical conclusions is that acoustic disturbances undergo transient growth in a combustion system with nonorthogonal eigenmodes. Such finite-time growth, which cannot be predicted by using classical linear theory might trigger high-amplitude self-sustained oscillations

  14. Experimental analysis of thermo-acoustic instabilities in a generic gas turbine combustor by phase-correlated PIV, chemiluminescence, and laser Raman scattering measurements

    Science.gov (United States)

    Arndt, Christoph M.; Severin, Michael; Dem, Claudiu; Stöhr, Michael; Steinberg, Adam M.; Meier, Wolfgang

    2015-04-01

    A gas turbine model combustor for partially premixed swirl flames was equipped with an optical combustion chamber and operated with CH4 and air at atmospheric pressure. The burner consisted of two concentric nozzles for separately controlled air flows and a ring of holes 12 mm upstream of the nozzle exits for fuel injection. The flame described here had a thermal power of 25 kW, a global equivalence ratio of 0.7, and exhibited thermo-acoustic instabilities at a frequency of approximately 400 Hz. The phase-dependent variations in the flame shape and relative heat release rate were determined by OH* chemiluminescence imaging; the flow velocities by stereoscopic particle image velocimetry (PIV); and the major species concentrations, mixture fraction, and temperature by laser Raman scattering. The PIV measurements showed that the flow field performed a "pumping" mode with varying inflow velocities and extent of the inner recirculation zone, triggered by the pressure variations in the combustion chamber. The flow field oscillations were accompanied by variations in the mixture fraction in the inflow region and at the flame root, which in turn were mainly caused by the variations in the CH4 concentration. The mean phase-dependent changes in the fluxes of CH4 and N2 through cross-sectional planes of the combustion chamber at different heights above the nozzle were estimated by combining the PIV and Raman data. The results revealed a periodic variation in the CH4 flux by more than 150 % in relation to the mean value, due to the combined influence of the oscillating flow velocity, density variations, and CH4 concentration. Based on the experimental results, the feedback mechanism of the thermo-acoustic pulsations could be identified as a periodic fluctuation of the equivalence ratio and fuel mass flow together with a convective delay for the transport of fuel from the fuel injector to the flame zone. The combustor and the measured data are well suited for the validation of

  15. Determination of the stability limit of a thermoacoustic engine by means of finite elements

    NARCIS (Netherlands)

    de Jong, Anne; Wijnant, Ysbrand H.; de Boer, Andries

    2013-01-01

    A finite element model is presented to obtain the stability limit of, as an example, 2D standing wave thermoacoustic engine. The stability limit is the required heating to obtain self-sustained (thermo)acoustic oscillations. The method used to obtain the stability limit is not restricted to the

  16. Mathematical Modeling of Nonstationary Separation Processes in Gas Centrifuge Cascade for Separation of Multicomponent Isotope Mixtures

    OpenAIRE

    Orlov Alexey; Ushakov Anton; Sovach Victor

    2016-01-01

    This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge casca...

  17. Transmission characteristics of acoustic amplifier in thermoacoustic engine

    International Nuclear Information System (INIS)

    Sun Daming; Qiu Limin; Wang Bo; Xiao Yong

    2008-01-01

    Thermoacoustic engines are promising in practical applications for the merits of simple configuration, reliable operation and environmentally friendly working gas. An acoustic amplifier can increase the output pressure amplitude of a thermoacoustic engine (TE) and improve the matching between the engine and its load. In order to make full use of an acoustic amplifier, the transmission characteristics are studied based on linear thermoacoustic theory. Computational and experimental results show that the amplifying ability of an acoustic amplifier is mainly determined by its geometry parameters and output resistance impedance. The amplifying ability of an acoustic amplifier with appropriate length and diameter reaches its maximum when the output resistance impedance is infinite. It is also shown that the acoustic amplifier consumes an amount of acoustic power when amplifying pressure amplitude and the acoustic power consumption increases with amplifying ratio. Furthermore, a novel cascade acoustic amplifier is proposed, which has a much stronger amplifying ability with reduced acoustic power consumption. In experiments, a two-stage cascade acoustic amplifier amplifies the pressure ratio from 1.177 to 1.62 and produces a pressure amplitude of 0.547 MPa with nitrogen of 2.20 MPa as working gas. Good agreements are obtained between the theoretical analysis and experimental results. This research is instructive for comprehensively understanding the mechanism and making full use of the acoustic amplifier

  18. Thermo-Acoustic Convertor for Space Power, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In Phase Sunpower looked at Thermoacoustic Stirling Heat Engines (TASHEs). These ranged from a TASHE which was sized for the heat from a single General Purpose Heat...

  19. Influence of shape and size of the particles on jigging separation of plastics mixture.

    Science.gov (United States)

    Pita, Fernando; Castilho, Ana

    2016-02-01

    Plastics are popular for numerous applications due to their high versatility and favourable properties such as endurance, lightness and cheapness. Therefore the generation of plastic waste is constantly increasing, becoming one of the larger categories in municipal solid waste. Almost all plastic materials are recyclable, but for the recycling to be possible it is necessary to separate the different types of plastics. The aim of this research was to evaluate the performance of the jig separation of bi-component plastic mixtures. For this study six granulated plastics had been used: Polystyrene (PS), Polymethyl methacrylate (PMMA), Polyethylene Terephthalate (PET-S, PET-D) and Polyvinyl Chloride (PVC-M, PVC-D). Plastics mixtures were subjected to jigging in a laboratorial Denver mineral jig. The results showed that the quality of the jigging separation varies with the mixture, the density differences and with the size and shape of the particles. In the case of particles with more regular shapes the quality of separation of bi-component plastic mixtures improved with the increase of the particle size. For lamellar particles the influence of particle size was minimal. In general, the beneficiation of plastics with similar densities was not effective, since the separation efficiency was lower than 25%. However, in bi-component plastic mixtures that join a low density plastic (PS) with a high density one (PMMA, PET-S, PET-D, PVC-M and PVC-D), the quality of the jigging separation was greatly improved. The PS grade in the sunk was less than 1% for all the plastic mixtures. Jigging proved to be an effective method for the separation of bi-component plastic mixtures. Jigging separation will be enhanced if the less dense plastic, that overflows, has a lamellar shape and if the denser plastic, that sinks, has a regular one. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Numerical results on noise-induced dynamics in the subthreshold regime for thermoacoustic systems

    Science.gov (United States)

    Gupta, Vikrant; Saurabh, Aditya; Paschereit, Christian Oliver; Kabiraj, Lipika

    2017-03-01

    Thermoacoustic instability is a serious issue in practical combustion systems. Such systems are inherently noisy, and hence the influence of noise on the dynamics of thermoacoustic instability is an aspect of practical importance. The present work is motivated by a recent report on the experimental observation of coherence resonance, or noise-induced coherence with a resonance-like dependence on the noise intensity as the system approaches the stability margin, for a prototypical premixed laminar flame combustor (Kabiraj et al., Phys. Rev. E, 4 (2015)). We numerically investigate representative thermoacoustic models for such noise-induced dynamics. Similar to the experiments, we study variation in system dynamics in response to variations in the noise intensity and in a critical control parameter as the systems approach their stability margins. The qualitative match identified between experimental results and observations in the representative models investigated here confirms that coherence resonance is a feature of thermoacoustic systems. We also extend the experimental results, which were limited to the case of subcritical Hopf bifurcation, to the case of supercritical Hopf bifurcation. We identify that the phenomenon has qualitative differences for the systems undergoing transition via subcritical and supercritical Hopf bifurcations. Two important practical implications are associated with the findings. Firstly, the increase in noise-induced coherence as the system approaches the onset of thermoacoustic instability can be considered as a precursor to the instability. Secondly, the dependence of noise-induced dynamics on the bifurcation type can be utilised to distinguish between subcritical and supercritical bifurcation prior to the onset of the instability.

  1. Experimental study of microwave-induced thermoacoustic imaging

    Science.gov (United States)

    Jacobs, Ryan T.

    Microwave-Induced Thermoacoustic Imaging (TAI) is a noninvasive hybrid modality which improves contrast by using thermoelastic wave generation induced by microwave absorption. Ultrasonography is widely used in medical practice as a low-cost alternative and supplement to magnetic resonance imaging (MRI). Although ultrasonography has relatively high image resolution (depending on the ultrasonic wavelength at diagnostic frequencies), it suffers from low image contrast of soft tissues. In this work samples are irradiated with sub-microsecond electromagnetic pulses inducing acoustic waves in the sample that are then detected with an unfocused transducer. The advantage of this hybrid modality is the ability to take advantage of the microwave absorption coefficients which provide high contrast in tissue samples. This in combination with the superior spatial resolution of ultrasound waves is important to providing a low-cost alternative to MRI and early breast cancer detection methods. This work describes the implementation of a thermoacoustic experiment using a 5 kW peak power microwave source.

  2. Numerical Simulation of Pressure Fluctuations in the Thermo-acoustic Transducer

    Directory of Open Access Journals (Sweden)

    D. A. Uglanov

    2015-01-01

    Full Text Available The article describes the features of numerical simulation of acoustic oscillation excitation in the resonators with a foam insert (regenerator to study the excitation of thermo-acoustic oscillations in the circuit of small-sized engine model on the pulse tube.The aim of this work is the numerical simulation of the emerging oscillations in thermoacoustic engine resonator at the standing wave. As a basis, the work takes a thermo-acoustic resonator model with the open end (without piston developed in DeltaEC software. The precalculated operation frequency of the given resonator model, as a quarter of the wave resonator, is ν = 560 Hz.The paper offers a simplified finite element resonator model and defines the harmonic law of the temperature distribution on regenerator. The time dependences of the speed and pressure amplitude for the open end of the resonator are given; the calculated value of the process operating frequency is approximately equal to the value of the frequency for a given length of the resonator. Key findings, as a result of study, are as follows:1. The paper shows a potential for using this ESI-CFD Advanced software to simulate the processes of thermal excitation of acoustic oscillations.2. Visualization of turbulent flow fluctuations in the regenerator zone extends the analysis capability of gas-dynamic processes.3. Difference between operating frequency of the process simulated by ESI-CFD Advanced and frequency value obtained by analytical methods is about 4%, which is evidence of the model applicability to study the acoustic parameters of thermo-acoustic transducers. Experimental results have proved these data.

  3. A family of inversion formulas in thermoacoustic tomography

    KAUST Repository

    Nguyen, Linh

    2009-01-01

    We present a family of closed form inversion formulas in thermoacoustic tomography in the case of a constant sound speed. The formulas are presented in both time-domain and frequency-domain versions. As special cases, they imply most

  4. Investigation on thermo-acoustic instability dynamic characteristics of hydrocarbon fuel flowing in scramjet cooling channel based on wavelet entropy method

    Science.gov (United States)

    Zan, Hao; Li, Haowei; Jiang, Yuguang; Wu, Meng; Zhou, Weixing; Bao, Wen

    2018-06-01

    As part of our efforts to find ways and means to further improve the regenerative cooling technology in scramjet, the experiments of thermo-acoustic instability dynamic characteristics of hydrocarbon fuel flowing have been conducted in horizontal circular tubes at different conditions. The experimental results indicate that there is a developing process from thermo-acoustic stability to instability. In order to have a deep understanding on the developing process of thermo-acoustic instability, the method of Multi-scale Shannon Wavelet Entropy (MSWE) based on Wavelet Transform Correlation Filter (WTCF) and Multi-Scale Shannon Entropy (MSE) is adopted in this paper. The results demonstrate that the developing process of thermo-acoustic instability from noise and weak signals is well detected by MSWE method and the differences among the stability, the developing process and the instability can be identified. These properties render the method particularly powerful for warning thermo-acoustic instability of hydrocarbon fuel flowing in scramjet cooling channels. The mass flow rate and the inlet pressure will make an influence on the developing process of the thermo-acoustic instability. The investigation on thermo-acoustic instability dynamic characteristics at supercritical pressure based on wavelet entropy method offers guidance on the control of scramjet fuel supply, which can secure stable fuel flowing in regenerative cooling system.

  5. Separation of rare earth mixtures by gas chromatography using dipivaloylmethane as complexing agent

    International Nuclear Information System (INIS)

    Golubtsova, V.Yu.; Luchinkin, V.V.; Martynenko, L.I.; Murav'eva, I.A.; Sokolov, D.N.

    1981-01-01

    Possibility of using dipivaloylmethave for quantitative separation of rare earth element mixtures under the regime of chromatography for preparative and analytical purposes, is studied. Introduction of β-diketone surplus into the chromatographic solution is shown to remove the necessity of column conditioning. It is stated that chelate solution should have concentration above the threshold one. The developed method is applicable for quantitative separation of some rare earth mixtures for preparative purposes, as well as for the analysis of rare earth mixtures, containing components in equivalent quantities [ru

  6. Separation of a target substance from a fluid or mixture using encapsulated sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D; Spadaccini, Christopher M; Stolaroff, Joshuah K; Bourcier, William L; Lewis, Jennifer A; Duoss, Eric B; Vericella, John J

    2014-09-16

    Method and apparatus for separating a target substance from a fluid or mixture. Capsules having a coating and stripping solvents encapsulated in the capsules are provided. The coating is permeable to the target substance. The capsules having a coating and stripping solvents encapsulated in the capsules are exposed to the fluid or mixture. The target substance migrates through the coating and is taken up by the stripping solvents. The target substance is separated from the fluid or mixture by driving off the target substance from the capsules.

  7. Anomalous separation of homogeneous particle-fluid mixtures: Further observations

    Science.gov (United States)

    Husain, H. S.; Hussain, F.; Goldshtik, M.

    1995-11-01

    Previously, we reported the puzzling phenomenon of separation of components from an initially uniform mixture (air and smoke) in a rotating flow device (a cylindrical can with a rotating end disk). Here we summarize further studies of this phenomenon through experiments, analysis of particle forces, and direct numerical simulation (DNS). Separation of spherical polystyrene particles when immersed in water or pure alcohol lends further credence to the phenomenon. We have studied the dependence of the particle-free column size and its establishment time on particle size, particle concentration, disk and cylinder Reynolds numbers, and fluid composition. The evolution of passive markers in DNS shows segregation similar to that observed in experiments, supporting our kinematic separation hypothesis. However, kinematic action, though important, is inadequate to explain the ``antidiffusion'' phenomenon. Although estimates show that known particle forces cannot account for the particle separation, experimental results suggest the action of a yet unknown lift force whose effect is magnified kinematically in our apparatus. At high particle concentrations or when a small amount of solute (e.g. sugar, salt, or alcohol) is added to water polystyrene particle mixtures, the flow within the column becomes unstable and the particle-free column loses its axial symmetry; this unusual behavior is not yet clearly understood.

  8. The Influence of the Density of Coconut Fiber as Stack in Thermo-Acoustics Refrigeration System

    Science.gov (United States)

    Hartulistiyoso, E.; Yulianto, M.; Sucahyo, L.

    2018-05-01

    An experimental study of using coconut fiber as stack with varying density in thermo-acoustics refrigeration system has been done. Stack is a device which is described as the “heart” in thermo-acoustics refrigeration system. The length of stack is a fix parameter in this experiment. The performance of the coconut fiber was evaluated from the density of stack (varied from 30%, 50% and 70%), position of stack (varied from 0 to 34 cm from the sound generator), and frequency of sound generator (varied from 150 Hz, 200Hz, 250Hz and 300Hz). The inside, outside, and environment temperatures were collected every second using Data Acquisition (DAQ). The result showed that the increase of stack density will increase the performance of thermo-acoustics refrigeration system. The higher density produced temperature differences in cold side and hot side of 5.4°C. In addition, the position of stack and frequency of sound generator have an important role in the performance of thermo-acoustics refrigeration system for all variations of the density.

  9. Thermoacoustic design using stem of goose down stack

    Science.gov (United States)

    Farikhah, Irna; Ristanto, Sigit; Idrus, Hadiyati; Kaltsum, Ummi; Faisal, Affandi; Setiawan, Ihsan; Setio Utomo, Agung Bambang

    2012-09-01

    Many refrigerators using CFC as a refrigerant are seen as the cause of the depletion of ozone. Hence, thermoacoustic was chosen as an alternative refrigerator that safe for environment. There are many variable that influenced the optimization of thermoacoustic design. One of them is thermal conductivity of material of stack. The Stack material must have a low thermal conductivity. In this research we used organic stack made of stem of goose down. It has superior thermal insulating. It means that they have the lowest thermal conductivity. The system uses no refrigerant or compressor, and the only mechanical moving part is the loudspeaker connected to a signal generator that produces the acoustic. The working fluid is air and the material of resonator is stainless steel. A series test on the laboratory found that there is a decrease of 5°C in temperature for about 2 minutes.

  10. A PROCESS FOR SEPARATING AZEOTROPIC MIXTURES BY EXTRACTIVE AND CONVECTIVE DISTILLATION

    Science.gov (United States)

    Frazer, J.W.

    1961-12-19

    A method is described for separating an azeotrope of carbon tetrachloride and 1,1,2,2-tetrafluorodinitroethane boiling at 60 deg C. The ndethod comnprises, specifically, feeding azeotrope vapors admixed with a non- reactive gas into an extractive distillation column heated to a temperature preferably somewhat above the boiling point of the constant boiling mixture. A solvent, di-n-butylphthalate, is metered into the column above the gas inlet and permitted to flow downward, earrying with it the higher bomling fraction, while the constituent having the lower boiling point passes out of the top of the column with the non-reactive gas and is collected in a nitrogen cold trap. Other solvents which alter the vapor pressure relationship may be substituted. The method is generally applicable to azeotropic mixtures. A number of specific mixtures whicb may be separated are disclosed. (AEC)

  11. Design and dynamic behaviour of a cold storage system combined with a solar powered thermoacoustic refrigerator

    International Nuclear Information System (INIS)

    Perier-Muzet, Maxime; Bedecarrats, Jean-Pierre; Stouffs, Pascal; Castaing-Lasvignottes, Jean

    2014-01-01

    A heat powered thermoacoustic refrigerator consists in a thermoacoustic engine that produces acoustic work utilizing heat, coupled to a thermoacoustic cooler that converts this acoustic energy into cooling effect. These machines have already proved their capability in laboratory or in space refrigeration. Previous studies have also demonstrated the possibility of using concentrated solar energy as thermal energy sources for low power heat driven thermoacoustic refrigerators. As other solar refrigeration systems, even if the cooling demand generally increases with the intensity of the solar radiation, one of the major difficulties is to insure a frigorific power supply when there is no, or low, solar radiation. The aim of this work is to study a kW scale solar thermoacoustic refrigerator capable to reach temperatures of the industrial refrigeration domain. This refrigerator is combined with a latent cold storage in order to guarantee a sufficient cooling capacity to face to refrigeration loads in spite of the production fluctuations. A description of the studied prototype is done and the model developed to describe the transient behaviour of the main components of this machine is introduced. The results obtained with a simulation of one week with real solar radiations are presented and the behaviour and the energetic performances of the entire system are analysed. Finally the impact of the sizing of the cold storage system is discussed. With the best storage design, the system is capable to supply a cooling power of 400 W at a temperature equal or lower than −20 °C with an average Coefficient Of Performance of the solar thermoacoustic refrigerator equal to 21%

  12. Computational Investigation on the performance of thermo-acoustically driven pulse tube refrigerator

    Science.gov (United States)

    Skaria, Mathew; Rasheed, K. K. Abdul; Shafi, K. A.; Kasthurirengan, S.; Behera, Upendra

    2017-02-01

    A Thermoacoustic Pulse Tube Refrigeration (TAPTR) system employs a thermo acoustic engine as the pressure wave generator instead of mechanical compressor. Such refrigeration systems are highly reliable due to the absence of moving components, structural simplicity and the use of environmental friendly working fluids. In the present work, a traveling wave thermoacoustic primmover (TWTAPM) has been developed and it is coupled to a pulse tube cryocooler. The performance of TAPTR depends on the operating and working fluid parameters. Simulation studies of the system has been performed using ANSYS Fluent and compared with experimental results.

  13. Towards numerical simulation of components of thermoacoustic devices with commercial CFD software: implementation of impedance boundary conditions and application to four different studies

    NARCIS (Netherlands)

    Bühler, Simon

    2015-01-01

    Thermoacoustic engines promise to be a cost effective and reliable alternative to traditional Stirling engines, as the function of the piston is fulfilled by an acoustic wave. For the design and development of thermoacoustic devices, the one-dimensional thermoacoustic equations are commonly used.

  14. Nontrivial influence of acoustic streaming on the efficiency of annular thermoacoustic prime movers

    International Nuclear Information System (INIS)

    Penelet, G.; Gusev, V.; Lotton, P.; Bruneau, M.

    2006-01-01

    The nonlinear processes controlling the time-dependent evolution of sound in annular thermoacoustic prime movers are studied. It is demonstrated that, under some heating conditions, the evolution of the temperature field induced by the excitation of acoustic streaming provides an additional amplification of sound which results in a complicated periodic onset and damping of thermoacoustic instability. The study of this particular example provides the opportunity to demonstrate that the excitation of acoustic streaming does not necessarily imply a decrease in the engine's efficiency

  15. Heat driven thermoacoustic cooler based on traveling-standing wave

    International Nuclear Information System (INIS)

    Kang Huifang; Zhou Gang; Li Qing

    2010-01-01

    This paper presents a heat driven thermoacoustic cooler system without any moving part. It consists of a thermoacoustic engine and a thermoacoustic cooler, and the former is the driving source of the latter. Both the engine and the cooler are located in one loop tube coupled with a resonator tube, and the acoustic power produced by the engine is used to drive the cooler directly. Both regenerators of the engine and the cooler are located in the near region of the pressure antinode, and operate in traveling-standing wave phase region. In the engine's regenerator, both components of the standing wave and the traveling wave realize the conversion from heat to acoustic energy. This improves the efficiency of the engine. In the cooler's regenerator, both components of the traveling wave and the standing wave pump heat from the cold end. This improves the efficiency of the cooler. At the operating point with a mean pressure of 22 bar, helium as working gas, a frequency of 234 Hz, and a heating power of 300 W, the experimental cooler provides a no-load temperature of -30 deg. C and a cooling power of 40 W at the cooling temperature of 0 deg. C. The total length of this cooler system is less than 1 m, which shows a good prospect for the domestic cooler system in room-temperature cooling such as food refrigeration and air-conditioning.

  16. Process and device for separating a gaseous mixture from isotope compounds

    International Nuclear Information System (INIS)

    Gajewski, W.

    1980-01-01

    The UF 6 -gas mixture is adiabatically expanded through a nozzle and cooled to below 100 K. The emerging gas mixture beam is then totally taken up by radiation technology by a large number of sequentially ignited pulsed lasers of the same or different frequencies. The selective initiation and chemical or physical separation takes place along a path 2 cm long. (DG) [de

  17. Separation of azeotropic mixtures of alcohols and water with FricDiff

    NARCIS (Netherlands)

    Breure, B.; Peters, E.A.J.F.; Kerkhof, P.J.A.M.

    2008-01-01

    FricDiff is an energy efficient separation process based on a difference in transport velocities of the components of a gas or vapor mixture when they diffuse through a sweep gas ('enhancer'). The separation process takes place inside the pores of a non-selective macro-porous barrier. In this paper

  18. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  19. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Science.gov (United States)

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  20. Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

    Directory of Open Access Journals (Sweden)

    Nadine Schmeling

    2010-08-01

    Full Text Available Functionalized copolyimides continue to attract much attention as membrane materials because they can fulfill the demands for industrial applications. Thus not only good separation characteristics but also high temperature stability and chemical resistance are required. Furthermore, it is very important that membrane materials are resistant to plasticization since it has been shown that this phenomenon leads to a significant increase in permeability with a dramatic loss in selectivity. Plasticization effects occur with most polymer membranes at high CO2 concentrations and pressures, respectively. Plasticization effects are also observed with higher hydrocarbons such as propylene, propane, aromatics or sulfur containing aromatics. Unfortunately, these components are present in mixtures of high commercial relevance and can be separated economically by single membrane units or hybrid processes where conventional separation units are combined with membrane-based processes. In this paper the advantages of carboxy group containing 6FDA (4,4′-hexafluoroisopropylidene diphthalic anhydride -copolyimides are discussed based on the experimental results for non cross-linked, ionically and covalently cross-linked membrane materials with respect to the separation of olefins/paraffins, e.g. propylene/propane, aromatic/aliphatic separation e.g. benzene/cyclohexane as well as high pressure gas separations, e.g. CO2/CH4 mixtures. In addition, opportunities for implementing the membrane units in conventional separation processes are discussed.

  1. Thermoacoustic sensor for nuclear fuel temperaturemonitoring and heat transfer enhancement

    Energy Technology Data Exchange (ETDEWEB)

    James A. Smith; Dale K. Kotter; Randall A. Alli; Steven L. Garrett

    2013-05-01

    A new acoustical sensing system for the nuclear power industry has been developed at The Pennsylvania State University in collaboration with Idaho National Laboratories. This sensor uses the high temperatures of nuclear fuel to convert a nuclear fuel rod into a standing-wave thermoacoustic engine. When a standing wave is generated, the sound wave within the fuel rod will be propagated, by acoustic radiation, through the cooling fluid within the reactor or spent fuel pool and can be monitored a remote location external to the reactor. The frequency of the sound can be correlated to an effective temperature of either the fuel or the surrounding coolant. We will present results for a thermoacoustic resonator built into a Nitonic-60 (stainless steel) fuel rod that requires only one passive component and no heat exchangers.

  2. Design, construction, and measurement of a large solar powered thermoacoustic cooler

    Science.gov (United States)

    Chen, Reh-Lin

    2001-07-01

    A device based on harnessing concentrated solar power in combination with using thermoacoustic principles has been built, instrumented, and tested. Its acoustic power is generated by solar radiation and is subsequently used to pump heat from external loads. The direct conversion between thermal and mechanical energy without going through any electronic stage makes the mechanism simple. Construction of the solar collector is also rather unsophisticated. It was converted from a 10-ft satellite dish with aluminized Mylar glued on the surface. The thermoacoustic device was mounted on the dish with its engine's hot side positioned near the focus of the parabolic dish, about 1 meter above the center of the dish. A 2-dimensional solar tracking system was built, using two servo motors to position the dish at pre-calculated coordinates. The solar powered thermoacoustic cooler is intended to be used where solar power is abundant and electricity may not be available or reliable. The cooler provides cooling during solar availability. Cooling can be maintained by the latent heat of ice when solar power is unattainable. The device has achieved cooling although compromised by gas leakage and thermal losses and was not able to provide temperatures low enough to freeze water. Improvements of the device are expected through modifications suggested herein.

  3. A thermoacoustic-Stirling heat engine: detailed study

    Science.gov (United States)

    Backhaus; Swift

    2000-06-01

    A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood.

  4. Homogeneous nucleation in phase separation of solid 3He-4He mixtures

    International Nuclear Information System (INIS)

    Poole, M.; Smith, A.; Maidanov, V.A.; Rudavskii, E.Ya.; Grigor'ev, V.N.; Slezov, V.V.; Saunders, J.; Cowan, B.

    2003-01-01

    NMR and pressure have been measured during phase separation in solid 3 He- 4 He mixtures. Spin echoes were used to observe bounded diffusion and to estimate the diffusion coefficient, size and nuclei concentration in the 3 He-enriched phase. The characteristic phase separation time constant of the mixture was found from pressure measurements. The results argue convincingly for homogeneous nucleation. The surface tension of the nuclei is found independently from NMR and from pressure measurements; the two determinations agree well and yield a surface tension coefficient of 4.9x10 -6 J m -2

  5. A family of inversion formulas in thermoacoustic tomography

    KAUST Repository

    Nguyen, Linh

    2009-10-01

    We present a family of closed form inversion formulas in thermoacoustic tomography in the case of a constant sound speed. The formulas are presented in both time-domain and frequency-domain versions. As special cases, they imply most of the previously known filtered backprojection type formulas. © 2009 AMERICAN INSTITUTE OF MATHEMATICAL SCIENCES.

  6. Friction Factor Correlation for Regenerator Working in a Travelling-Wave Thermoacoustic System

    Directory of Open Access Journals (Sweden)

    Fatimah A. Z. Mohd Saat

    2017-03-01

    Full Text Available Regenerator is a porous solid structure which is important in the travelling-wave thermoacoustic system. It provides the necessary contact surface and thermal capacity for the working gas to undergo a thermodynamic cycle under acoustic oscillatory flow conditions. However, it also creates a pressure drop that could degrade the overall system performance. Ideally, in a travelling-wave system, the phase angle between oscillating pressure and velocity in the regenerator should be zero, or as close to zero as possible. In this study, the hydrodynamic condition of a regenerator has been investigated both experimentally (in a purpose-built rig providing a travelling-wave phasing and numerically. A two-dimensional ANSYS FLUENT CFD model, capturing the important features of the experimental conditions, has been developed. The findings suggest that a steady-state correlation, commonly used in designing thermoacoustic systems, is applicable provided that the travelling-wave phase angle is maintained. However, for coarse mesh regenerators, the results show interesting “phase shifting” phenomena, which may limit the correlation validity. Current experimental and CFD studies are important for predicting the viscous losses in future models of thermoacoustic systems.

  7. Mathematics of Photoacoustic and Thermoacoustic Tomography

    KAUST Repository

    Kuchment, Peter; Kunyansky, Leonid

    2011-01-01

    The chapter surveys the mathematical models, problems, and algorithms of the thermoacoustic tomography (TAT) and photoacoustic tomography (PAT). TAT and PAT represent probably the most developed of the several novel “hybrid” methods of medical imaging. These new modalities combine different physical types of waves (electromagnetic and acoustic in case of TAT and PAT) in such a way that the resolution and contrast of the resulting method are much higher than those achievable using only acoustic or electromagnetic measurements.

  8. Ionic liquids for separation of olefin-paraffin mixtures

    Science.gov (United States)

    Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

    2013-09-17

    The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

  9. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    Science.gov (United States)

    Hupp, Joseph T [Northfield, IL; Mulfort, Karen L [Chicago, IL; Snurr, Randall Q [Evanston, IL; Bae, Youn-Sang [Evanston, IL

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  10. Thermodynamic measurement and analysis of dual-temperature thermoacoustic oscillations for energy harvesting application

    International Nuclear Information System (INIS)

    Zhao, Dan; Ji, Chenzhen; Li, Shihuai; Li, Junwei

    2014-01-01

    The present work considers energy harvesting by implementing both thermo- and piezo-electric power generation modules on a bifurcating tube, which produces dual-temperature thermoacoustic oscillations. The present system distinguished from the conventional standing-wave one does not involve heat exchangers and uses two different energy conversion processes to produce electricity. To measure and analyze the sound waves generated, an infrared thermal imaging camera, hot wire anemometry, and two arrays of K-type thermocouples and microphones are employed. It is found that the total electric power is approximately 5.71 mW, of which the piezo module produces about 0.21 mW. It is about 61% more than that generated by a similar conduction-driven thermo-acoustic-piezo harvester. In order to gain insight on the heat-driven acoustic oscillations and to simulate the experiment, thermodynamic laws are used to develop a nonlinear thermoacoustic model. Comparison is then made between the numerical and experimental results. Good agreement is obtained in terms of frequency and sound pressure level. Finally, Rayleigh index is examined to characterize the conversion between thermal and sound energy. In addition, energy redistribution between different thermoacoustic modes is estimated. It is found that lower frequency thermoacoustic oscillations are easier to trigger. - Highlights: • Energy harvesting from thermo- and piezo-electric diaphragms is obtained. • Total electrical power is approximately 5.71 mW. • Thermodynamic analysis of heat-driven oscillations is performed. • Rayleigh index characterizing heat-to-sound conversion is estimated. • Energy redistribution between various eigenmodes is calculated

  11. Output characteristics of Stirling thermoacoustic engine

    International Nuclear Information System (INIS)

    Sun Daming; Qiu Limin; Wang Bo; Xiao Yong; Zhao Liang

    2008-01-01

    A thermoacoustic engine (TE), which converts thermal energy into acoustic power by the thermoacoustic effect, shows several advantages due to the absence of moving parts, such as high reliability and long lifetime associated with reduced manufacturing costs. Power output and efficiency are important criteria of the performance of a TE. In order to increase the acoustic power output and thermal efficiency of a Stirling TE, the acoustic power distribution in the engine is studied with the variable load method. It is found that the thermal efficiency is independent of the output locations along the engine under the same acoustic power output. Furthermore, when the pressure ratio is kept constant at one location along the TE, it is beneficial to increasing the thermal efficiency by exporting more acoustic power. With nitrogen of 2.5 MPa as working gas and the pressure ratio at the compliance of 1.20 in the experiments, the acoustic power is measured at the compliance and the resonator simultaneously. The maximum power output, thermal efficiency and exergy efficiency reach 390.0 W, 11.2% and 16.0%, which are increased by 51.4%, 24.4% and 19.4%, respectively, compared to those with a single R-C load with 750 ml reservoir at the compliance. This research will be instructive for increasing the efficiency and making full use of the acoustic energy of a TE

  12. One-dimensional acoustic modeling of thermoacoustic instabilities (on cd)

    NARCIS (Netherlands)

    van Kampen, J.F.; Huls, R.A.; Kok, Jacobus B.W.; van der Meer, Theodorus H.; Nilsson, A.; Boden, H.

    2003-01-01

    In this paper the acoustic stability of a premixed turbulent natural gas flame confined in a combustor is investigated. Specifically when the flame is operated in a lean premixed mode, the thermoacoustic system is known to exhibit instabilities. These arise from a feedback mechanism between the

  13. Thermoacoustics a unifying perspective for some engines and refrigerators

    CERN Document Server

    Swift, Gregory W

    2017-01-01

    This updated new edition provides an introduction to the field of thermoacoustics. All of the key aspects of the topic are introduced, with the goal of helping the reader to acquire both an intuitive understanding and the ability to design hardware, build it, and assess its performance. Weaving together intuition, mathematics, and experimental results, this text equips readers with the tools to bridge the fields of thermodynamics and acoustics. At the same time, it remains firmly grounded in experimental results, basing its discussions on the distillation of a body of experiments spanning several decades and countries. The book begins with detailed treatment of the fundamental physical laws that underlie thermoacoustics. It then goes on to discuss key concepts, including simple oscillations, waves, power, and efficiency. The remaining portions of the book delve into more advanced topics and address practical concerns in applications  chapters on hardware and m easurements. With its careful progression and e...

  14. Characterization and detection of thermoacoustic combustion oscillations based on statistical complexity and complex-network theory

    Science.gov (United States)

    Murayama, Shogo; Kinugawa, Hikaru; Tokuda, Isao T.; Gotoda, Hiroshi

    2018-02-01

    We present an experimental study on the characterization of dynamic behavior of flow velocity field during thermoacoustic combustion oscillations in a turbulent confined combustor from the viewpoints of statistical complexity and complex-network theory, involving detection of a precursor of thermoacoustic combustion oscillations. The multiscale complexity-entropy causality plane clearly shows the possible presence of two dynamics, noisy periodic oscillations and noisy chaos, in the shear layer regions (1) between the outer recirculation region in the dump plate and a recirculation flow in the wake of the centerbody and (2) between the outer recirculation region in the dump plate and a vortex breakdown bubble away from the centerbody. The vertex strength in the turbulence network and the community structure of the vorticity field can identify the vortical interactions during thermoacoustic combustion oscillations. Sequential horizontal visibility graph motifs are useful for capturing a precursor of themoacoustic combustion oscillations.

  15. Amide-induced phase separation of hexafluoroisopropanol-water mixtures depending on the hydrophobicity of amides.

    Science.gov (United States)

    Takamuku, Toshiyuki; Wada, Hiroshi; Kawatoko, Chiemi; Shimomura, Takuya; Kanzaki, Ryo; Takeuchi, Munetaka

    2012-06-21

    Amide-induced phase separation of hexafluoro-2-propanol (HFIP)-water mixtures has been investigated to elucidate solvation properties of the mixtures by means of small-angle neutron scattering (SANS), (1)H and (13)C NMR, and molecular dynamics (MD) simulation. The amides included N-methylformamide (NMF), N-methylacetamide (NMA), and N-methylpropionamide (NMP). The phase diagrams of amide-HFIP-water ternary systems at 298 K showed that phase separation occurs in a closed-loop area of compositions as well as an N,N-dimethylformamide (DMF) system previously reported. The phase separation area becomes wider as the hydrophobicity of amides increases in the order of NMF amides due to the hydrophobic interaction gives rise to phase separation of the mixtures. In contrast, the disruption of HFIP clusters causes the recovery of the homogeneity of the ternary systems. The present results showed that HFIP clusters are evolved with increasing amide content to the lower phase separation concentration in the same mechanism among the four amide systems. However, the disruption of HFIP clusters in the NMP and DMF systems with further increasing amide content to the upper phase separation concentration occurs in a different way from those in the NMF and NMA systems.

  16. Robust optimization of psychotropic drug mixture separation in hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Rakić, Tijana; Jovanović, Marko; Dumić, Aleksandra; Pekić, Marina; Ribić, Sanja; Stojanović, Biljana Jancić

    2013-01-01

    This paper presents multiobjective optimization of complex mixtures separation in hydrophilic interaction liquid chromatography (HILIC). The selected model mixture consisted of five psychotropic drugs: clozapine, thioridazine, sulpiride, pheniramine and lamotrigine. Three factors related to the mobile phase composition (acetonitrile content, pH of the water phase and concentration of ammonium acetate) were optimized in order to achieve the following goals: maximal separation quality, minimal total analysis duration and robustness of an optimum. The consideration of robustness in early phases of the method development provides reliable methods with low risk for failure in validation phase. The simultaneous optimization of all goals was achieved by multiple threshold approach combined with grid point search. The identified optimal separation conditions (acetonitrile content 83%, pH of the water phase 3.5 and ammonium acetate content in water phase 14 mM) were experimentally verified.

  17. Separation of H-D mixtures by cryogenic distillation

    International Nuclear Information System (INIS)

    Luo Yangming; Gu Mei; Wang Heyi; Liu Jun; Fu Zhonghua; Xia Xiulong; Liu Yunnu; Weng Kuiping; Xie Bo; Ren Xingbi

    2007-01-01

    In this paper, separation of hydrogen-deuterium mixtures were performed on a cryogenic distillation apparatus. The results show that the D/H ratio in the reboiler reduced to 1.27x10 -2 at 120h with a flow flux of 5mol/h of the gas mixture in D/H ratio of 1.4xl0 -4 . The enrichment effect increased apparently with D/H ratio of the feeding gas. However, the deuterium content in the top of distillation column increased with the deuterium content in the reboiler, and the de-deuterium efficiencies decreased. In the full reflux experiment, the de-deuterium efficiency increased with heating power of the reboiler, and the inside pressure in the distillation column increased, too. It was necessary that suitable heating power should be chosen in order to control operation pressure in the cryogenic distillation process. (authors)

  18. Open cycle thermoacoustics

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Robert Stowers [Georgia Inst. of Technology, Atlanta, GA (United States)

    2000-01-01

    A new type of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process is discussed and experimentally demonstrated. The gas flowing through this device can be heated or cooled in a series of semi-open cyclic steps. The combination of open and cyclic flows makes possible the elimination of some or all of the heat exchangers (with their associated irreversibility). Heat is directly exchanged with the process fluid as it flows through the device when operating as a refrigerator, producing a staging effect that tends to increase First Law thermodynamic efficiency. An open-flow thermoacoustic refrigerator was built to demonstrate this concept. Several approaches are presented that describe the physical characteristics of this device. Tests have been conducted on this refrigerator with good agreement with a proposed theory.

  19. Numerical investigation of a looped-tube travelling-wave thermoacoustic engine with a bypass pipe

    International Nuclear Information System (INIS)

    Al-Kayiem, Ali; Yu, Zhibin

    2016-01-01

    A new configuration (“a looped-tube with a bypass pipe”) was recently proposed for low temperature travelling wave thermoacoustic engines and a prototype using atmospheric air as the working gas achieved an onset temperature difference as low as 65 °C. However, no further research has been reported about this new configuration to reveal its advantages and disadvantages. This paper aims to analyse this type of engine through a comprehensive numerical research. An engine of this type having dimensions similar to the reported prototype was firstly modelled. The calculated results were then qualitatively compared with the reported experimental data, showing a good agreement. The working principle of the engine was demonstrated and analysed. The research results show that an engine with such a bypass configuration essentially operates on the same thermodynamic principle as other travelling wave thermoacoustic engines, differing only in the design of the acoustic resonator. Both extremely short regenerators and a near-travelling wave resonator minimise the engine's acoustic losses, and thus significantly reduce its onset temperature difference. However, such short regenerators likely cause severe heat conduction losses, especially if the engine is applied to heat sources with higher temperatures. Furthermore, the acoustic power flowing back to the engine core is relatively low, while a large stream of acoustic power has to propagate within its resonator to maintain an acoustic resonance, potentially leading to low power density. The model was then applied to design an engine with a much longer regenerator and higher mean pressure to increase its power density. A thermoacoustic cooler was also added to the engine to utilise its acoustic power, allowing the evaluation of thermal efficiency. The pros and cons of the engine configuration are then discussed. - Highlights: • Analysed the working principle of a bypass type thermoacoustic engine. • Analysed the pros and

  20. A thermoacoustic-Stirling heat engine: Detailed study

    International Nuclear Information System (INIS)

    Backhaus, S.; Swift, G. W.

    2000-01-01

    A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood. (c) 2000 Acoustical Society of America

  1. Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

    KAUST Repository

    Pan, Yichang; Li, Tao; Lestari, Gabriella; Lai, Zhiping

    2012-01-01

    The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed

  2. Blind separation of more sources than sensors in convolutive mixtures

    DEFF Research Database (Denmark)

    Olsson, Rasmus Kongsgaard; Hansen, Lars Kai

    2006-01-01

    We demonstrate that blind separation of more sources than sensors can be performed based solely on the second order statistics of the observed mixtures. This a generalization of well-known robust algorithms that are suited for equal number of sources and sensors. It is assumed that the sources...

  3. Fission-powered in-core thermoacoustic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Steven L. [Graduate Program in Acoustics, Penn State University, University Park, Pennsylvania 16802 (United States); Smith, James A. [Fundamental Fuel Properties, Idaho National Laboratory, Idaho Falls, Idaho 83415 (United States); Smith, Robert W. M. [Applied Research Laboratory, Penn State University, State College, Pennsylvania 16804 (United States); Heidrich, Brenden J. [Nuclear Science User Facilities, Idaho National Laboratory, Idaho Falls, Idaho 83415 (United States); Heibel, Michael D. [Global Technology Development, Westinghouse Electric Company, Cranberry Township, Pennsylvania 16066 (United States)

    2016-04-04

    A thermoacoustic engine is operated within the core of a nuclear reactor to acoustically telemeter coolant temperature (frequency-encoded) and reactor power level (amplitude-encoded) outside the reactor, thus providing the values of these important parameters without external electrical power or wiring. We present data from two hydrophones in the coolant (far from the core) and an accelerometer attached to a structure outside the reactor. These signals have been detected even in the presence of substantial background noise generated by the reactor's fluid pumps.

  4. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

    Directory of Open Access Journals (Sweden)

    K. Rambabu

    2014-01-01

    Full Text Available A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

  5. Investigation of quantitative separation of thorium, uranium, neptunium and plutonium from complex radiochemical mixtures

    International Nuclear Information System (INIS)

    Ushatskij, V.N.; Preobrazhenskaya, L.D.; Kolychev, V.B.; Gugel', E.S.

    1979-01-01

    Quantitative separation of actinides and their radiochemical purification with the aid of TBP with subsequent separation of thorium and quantitative separation of U, Np and Pu with the aid of D2EHPA have been studied. The method has been developed for quantitative extraction-chromatographic separation and radiochemical purification of nanogram amounts of U, Pu and microgram amounts of Th and Np from complex radiochemical mixtures containing both fragment radioisotopes and non-radioactive macrocomponents ( Fe,Al,Mg,Mn, Na and others). The method calls for application of one-extraction-chromatographic column with TBP and one column with D2EHPA. Thorium is separated at the first stage since it does not form complexes in a chloride solution during washing of the sorption column with 6. OM HCl. Npsup((4)) and Pusup((3)) required for separation are stabilized with the aid of hydrazine and hydroxylamine mixture. The yield of each of the above-cited actinide elements during the complete two-stage separation and at the stage of their separation varies within the range of 98.5-99.3%

  6. Thermo-acoustic coupling in can-annular combustors : A numerical investigation

    NARCIS (Netherlands)

    Farisco, Federica; Panek, Lukasz; Kok, Jim B.W.; Pent, Jared; Rajaram, Rajesh

    2015-01-01

    Thermo-acoustic instabilities in modern, high power density gas turbines need to be predicted and understood in order to avoid unexpected damage and engine failure. While the annular combustor design is expected to suffer from the occurrence of transverse waves and burner-to-burner acoustic

  7. Orthogonal experimental study on high frequency cascade thermoacoustic engine

    International Nuclear Information System (INIS)

    Hu Zhongjun; Li Qing; Li Zhengyu; Li Qiang

    2008-01-01

    Orthogonal experiment design and variance analysis were adopted to investigate a miniature cascade thermoacoustic engine, which consisted of one standing wave stage and one traveling wave stage in series, operating at about 470 Hz, using helium as the working gas. Optimum matching of the heater powers between stages was very important for the performance of a cascade thermoacoustic engine, which was obtained from the orthogonal experiments. The orthogonal experiment design considered three experimental factors, i.e. the charging pressure and the heater powers in the two stages, which varied on five different levels, respectively. According to the range analysis and variance analysis from the orthogonal experiments, the charging pressure was the most sensitive factor influencing the dynamic pressure amplitude and onset temperature. The total efficiency and the dynamic pressure amplitude increased when the traveling wave stage heater power increased. The optimum ratio of the heater powers between the traveling wave stage and the standing wave stage was about 1.25, compromising the total efficiency with the dynamic pressure amplitude

  8. Thermo-acoustic instabilities in lean premixed swirl-stabilized combustion and their link to acoustically coupled and decoupled flame macrostructures

    KAUST Repository

    Taamallah, Soufien

    2015-01-01

    © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved. We investigate the onset of thermo-acoustic instabilities and their link to the mean flame configurations - or macrostructures - under acoustically coupled and decoupled conditions. Methane-hydrogen mixtures are used to explore the role of the fuel in changing the flame macrostructure, as determined by chemilumi-nescence, as the equivalence ratio (φ) varies. We observe four different configurations: a columnar flame (I); a bubble-columnar flame (II); a single conical flame (III); and a double conical flame (IV). We also observe different thermo-acoustic modes in the lean regime investigated, φ ∈ [0.5-0.75], that correspond to different flame configurations. By changing the combustor length without affecting the underlying flow, the resonant modes of the combustor are shifted to higher frequencies allowing for the decoupling of heat release fluctuations and the acoustic field over a range of equivalence ratio. We find that the same flame macrostructures observed in the long, acoustically coupled combustor arise in the short, acoustically decoupled combustor and transition at similar equivalence ratios in both combustors. The onset of the first fully unstable mode in the long combustor occurs at similar equivalence ratio as the flame transition from configuration III to IV. In the acoustically decoupled case, this transition occurs gradually starting with the intermittent appearance of a flame in the outer recirculation zone (ORZ). Spectral analysis of this phenomenon, referred to as "ORZ flame flickering" shows the existence of an unsteady event occurring over a narrow frequency band centered around 28 Hz along with a weaker broadband region at lower frequency in the range [1-10] Hz. The tone at 28 Hz is shown to be associated with the azimuthal advection of the flame by the outer recirculation zone flow. Changes in the fuel composition, by adding hydrogen (up to 20%), do not

  9. Fixed-Point Algorithms for the Blind Separation of Arbitrary Complex-Valued Non-Gaussian Signal Mixtures

    Directory of Open Access Journals (Sweden)

    Douglas Scott C

    2007-01-01

    Full Text Available We derive new fixed-point algorithms for the blind separation of complex-valued mixtures of independent, noncircularly symmetric, and non-Gaussian source signals. Leveraging recently developed results on the separability of complex-valued signal mixtures, we systematically construct iterative procedures on a kurtosis-based contrast whose evolutionary characteristics are identical to those of the FastICA algorithm of Hyvarinen and Oja in the real-valued mixture case. Thus, our methods inherit the fast convergence properties, computational simplicity, and ease of use of the FastICA algorithm while at the same time extending this class of techniques to complex signal mixtures. For extracting multiple sources, symmetric and asymmetric signal deflation procedures can be employed. Simulations for both noiseless and noisy mixtures indicate that the proposed algorithms have superior finite-sample performance in data-starved scenarios as compared to existing complex ICA methods while performing about as well as the best of these techniques for larger data-record lengths.

  10. Experimental study on a co-axial pulse tube cryocooler driven by a small thermoacoustic stirling engine

    Science.gov (United States)

    Chen, M.; Ju, L. Y.; Hao, H. X.

    2014-01-01

    Small scale thermoacoustic heat engines have advantages in fields like space exploration and domestic applications considering small space occupation and ease of transport. In the present paper, the influence of resonator diameter on the general performance of a small thermoacoustic Stirling engine was experimentally investigated using helium as the working gas. Reducing the diameter of the resonator appropriately is beneficial for lower onset heating temperature, lower frequency and higher pressure amplitude. Based on the pressure distribution in the small thermoacoustic engine, an outlet for the acoustic work transmission was made to combine the engine and a miniature co-axial pulse tube cooler. The cooling performance of the whole refrigeration system without any moving part was tested. Experimental results showed that further efforts are required to optimize the engine performance and its match with the co-axial pulse tube cooler in order to obtain better cooling performance, compared with its original operating condition, driven by a traditional electrical linear compressor.

  11. Pervaporation Separation of Water-Ethanol Mixtures Using Organic-Inorganic Nanocomposite Membranes

    Science.gov (United States)

    Preyssler type heteropolyacid viz., H14[NaP5W30O110] incorporated chitosan nanocomposite membranes (NCMs) were prepared by solution casting, characterized using a variety of techniques and employed in the pervaporation separation of water-ethanol mixtures as a function of feed wa...

  12. Radiation-induced thermoacoustic imaging

    International Nuclear Information System (INIS)

    Bowen, T.

    1984-01-01

    This invention provides a new technique for obtaining information non-invasively on the composition and structures of a material or body by detecting radiation-induced thermoacoustic image features. This is accomplished by utilizing the acoustic wave generated by sudden thermal stress. The sudden thermal stress is induced by a pulse of radiation which deposits energy causing a rapid, but very small, rise of temperature (typically, ΔT approximately 10sup(-6) - 10sup(-5) deg C). The radiation may be ionizing radiation, such as high energy electrons, photons (x-rays), neutrons, or other charged particles or it may be non-ionizing radiation, such as R.F. and microwave electromagnetic radiation and ultrasonic radiation. The choice of radiation depends on the nature of the body to be imaged and the type of information desired

  13. Ionic-Liquid Based Separation of Azeotropic Mixtures

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2014-01-01

    methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria such as stabi......methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria...... [C1MIM][DMP]. For the final evaluation, the best candidates for aqueous systems were used as entrainers, and then the vapor-liquid equilibrium (VLE) of the ternary systems containing ILs was predicted by the Non Random Two Liquids (NRTL) model to confirm the breaking of the azeotrope. Based...... on minimum concentration of the ILs required to break the given azeotrope, the best ILs as entrainers for water + ethanol and water + isopropanol azeotropic mixtures were [C1MIM][DMP] and [C2MIM][N(CN)2], respectively....

  14. Thermoacoustic and thermoreflectance imaging of biased integrated circuits: Voltage and temperature maps

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Rosales, E.; Cedeño, E. [Gleb Wataghin Physics Institute, University of Campinas - Unicamp, 13083-859 Campinas, SP (Brazil); Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); Hernandez-Wong, J. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); CONACYT, México, DF, México (Mexico); Rojas-Trigos, J. B.; Marin, E. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); Gandra, F. C. G.; Mansanares, A. M., E-mail: manoel@ifi.unicamp.br [Gleb Wataghin Physics Institute, University of Campinas - Unicamp, 13083-859 Campinas, SP (Brazil)

    2016-07-25

    In this work a combined thermoacoustic and thermoreflectance set-up was designed for imaging biased microelectronic circuits. In particular, it was used with polycrystalline silicon resistive tracks grown on a monocrystalline Si substrate mounted on a test chip. Thermoreflectance images, obtained by scanning a probe laser beam on the sample surface, clearly show the regions periodically heated by Joule effect, which are associated to the electric current distribution in the circuit. The thermoacoustic signal, detected by a pyroelectric/piezoelectric sensor beneath the chip, also discloses the Joule contribution of the whole sample. However, additional information emerges when a non-modulated laser beam is focused on the sample surface in a raster scan mode allowing imaging of the sample. The distribution of this supplementary signal is related to the voltage distribution along the circuit.

  15. Separation of molecular hydrogen isotope mixtures on zeolite NaX-3M

    International Nuclear Information System (INIS)

    Polevoj, A.S.; Yudin, I.P.

    1984-01-01

    The transfer unito height (TUH) have been determined at separation of the H 2 -D 2 mixture using zeolite NaX-3M depending on temperature and linear gas flow rate in the column. Experimentally the TUH value has been determined by the method of stepped variation of the concentration of one of the separated components at the entrance into the column and measurement of the substance front wash-out at the outlet. The results of determining TUH in the column of 10 mm diameter filled by the zeolite immobile layer with granules of 2-3 mm size show that with increasing the temperature from 77 K to 87.3 K TUH decreases while at constant temperature it increases with the growth of linear gas flow rate. The mentioned above circumstances testify to the essential contribution to the TUH value of the hydrogen diffusion process in the sorbent grain. The given TUH absolute values indicate the high rate of interphase isotope exchange at separation of the H 2 -D 2 mixture using NaX-3M zeolite

  16. Membrane Separation of Gas Mixtures under the Influence of Resonance Radiation.

    Czech Academy of Sciences Publication Activity Database

    Levdansky, Valerij Vladimirovič; Izák, Pavel

    2017-01-01

    Roč. 173, FEB (2017), s. 93-98 ISSN 1383-5866 R&D Projects: GA ČR GA14-12695S Institutional support: RVO:67985858 Keywords : membranes * gas mixture * separation Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 3.359, year: 2016

  17. Oscillatory flows in jet pumps: towards design guidelines for thermoacoustic applications

    NARCIS (Netherlands)

    Oosterhuis, Joris

    2016-01-01

    Thermoacoustic engines are an interesting alternative to conventional heat engines (such as Stirling engines) due to the absence of moving parts in the hot region and the small temperature difference required to operate. These engines can provide a durable solution in, for example, waste heat

  18. Thermo-acoustic cross-talk between cans in a can-annular combustor

    NARCIS (Netherlands)

    Farisco, Federica; Panek, Lukasz; Kok, Jim B.W.

    2017-01-01

    Thermo-acoustic instabilities in gas turbine engines are studied to avoid engine failure. Compared to the engines with annular combustors, the can-annular combustor design should be less vulnerable to acoustic burner-to-burner interaction, since the burners are acoustically coupled only by the

  19. CONCEPTUAL DESIGN OF NON-IDEAL MIXTURE SEPARATION WITH LIGHT ENTRAINERS

    Directory of Open Access Journals (Sweden)

    W. Shen

    Full Text Available Abstract A method is proposed to study the separation of minimum-, maximum-boiling azeotropic, and low volatility mixtures with a light entrainer, to investigate feasible regions of the key operating parameters reboil ratio (S and entrainer - feed flowrate ratio (FE/F for continuous processes. The thermodynamic topological predictions are carried out for 1.0-2, 1.0-1a, and 0.0-1 Serafimov's class diagrams. It relies upon the knowledge of residue curve maps, along with the univolatility line, and it enables the prediction of possible products at the bottom of the column and limiting values of FE/F. The profiles of the stripping, extractive, and rectifying sections are calculated by equations considering S and FE/F, and they bring information about the location of singular points and possible composition profile separatrices that could impair process feasibility. Providing specified product composition and recovery, the approximate calculations are compared with rigorous simulations of extractive distillation processes. Separating non-ideal mixtures using a light entrainer provides more opportunities for the case when it is not easy to find an appropriate heavy or intermediate entrainer.

  20. Tunable integration of absorption-membrane-adsorption for efficiently separating low boiling gas mixtures near normal temperature

    Science.gov (United States)

    Liu, Huang; Pan, Yong; Liu, Bei; Sun, Changyu; Guo, Ping; Gao, Xueteng; Yang, Lanying; Ma, Qinglan; Chen, Guangjin

    2016-01-01

    Separation of low boiling gas mixtures is widely concerned in process industries. Now their separations heavily rely upon energy-intensive cryogenic processes. Here, we report a pseudo-absorption process for separating low boiling gas mixtures near normal temperature. In this process, absorption-membrane-adsorption is integrated by suspending suitable porous ZIF material in suitable solvent and forming selectively permeable liquid membrane around ZIF particles. Green solvents like water and glycol were used to form ZIF-8 slurry and tune the permeability of liquid membrane surrounding ZIF-8 particles. We found glycol molecules form tighter membrane while water molecules form looser membrane because of the hydrophobicity of ZIF-8. When using mixing solvents composed of glycol and water, the permeability of liquid membrane becomes tunable. It is shown that ZIF-8/water slurry always manifests remarkable higher separation selectivity than solid ZIF-8 and it could be tuned to further enhance the capture of light hydrocarbons by adding suitable quantity of glycol to water. Because of its lower viscosity and higher sorption/desorption rate, tunable ZIF-8/water-glycol slurry could be readily used as liquid absorbent to separate different kinds of low boiling gas mixtures by applying a multistage separation process in one traditional absorption tower, especially for the capture of light hydrocarbons. PMID:26892255

  1. Thermoacoustic focusing lens by symmetric Airy beams with phase manipulations

    Science.gov (United States)

    Liu, Chen; Xia, Jian-Ping; Sun, Hong-Xiang; Yuan, Shou-Qi

    2017-12-01

    We report the realization of broadband acoustic focusing lenses based on two symmetric thermoacoustic phased arrays of Airy beams, in which the units of thermoacoustic phase control are designed by employing air with different temperatures surrounded by rigid insulated boundaries and thermal insulation films. The phase delays of the transmitted and reflected units could cover a whole 2π interval, which arises from the change of the sound velocity of air induced by the variation of the temperature. Based on the units of phase control, we design the transmitted and reflected acoustic focusing lenses with two symmetric Airy beams, and verify the high self-healing focusing characteristic and the feasibility of the thermal insulation films. Besides, the influences of the bending angle of the Airy beam on the focusing performance are discussed in detail. The proposed acoustic lens has advantages of broad bandwidth (about 4.8 kHz), high focusing performance, self-healing feature, and simple structure, which enable it to provide more schemes for acoustic focusing. It has excellent potential applications in acoustic devices.

  2. Use of separating nozzles or ultra-centrifuges for obtaining helium from gas mixtures containing helium

    International Nuclear Information System (INIS)

    Reimann, T.

    1987-01-01

    To obtain helium from gas mixtures containing helium, particularly from natural gas, it is proposed to match the dimensions of the separation devices for a ratio of the molecular weights to be separated of 4:1 of more, which ensures a higher separation factor and therefore a smaller number of separation stages to be connected in series. The process should make reasonably priced separation of helium possible. (orig./HP) [de

  3. Methods of separating short half-life radionuclides from a mixture of radionuclides

    International Nuclear Information System (INIS)

    Bray, L.A.; Ryan, J.L.

    1998-01-01

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of 223 Ra and 225 Ac, from a radionuclide ''cow'' of 227 Ac or 229 Th respectively. The method comprises the steps of (a) permitting ingrowth of at least one radionuclide daughter from said radionuclide ''cow'' forming an ingrown mixture; (b) insuring that the ingrown mixture is a nitric acid ingrown mixture; (c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the ''cow'' from at least one radionuclide daughter; (d) insuring that the at least one radionuclide daughter contains the radionuclide product; (e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and (f) recycling the at least one radionuclide daughter by adding it to the ''cow''. In one embodiment the radionuclide ''cow'' is the 227 Ac, the at least one daughter radionuclide is a 227 Th and the product radionuclide is the 223 Ra and the first nitrate form ion exchange column passes the 227 Ac and retains the 227 Th. In another embodiment the radionuclide ''cow'' is the 229 Th, the at least one daughter radionuclide is a 225 Ra and said product radionuclide is the 225 Ac and the 225 Ac and nitrate form ion exchange column retains the 229 Th and passes the 225 Ra/Ac. 8 figs

  4. Thermoacoustic model of a modified free piston Stirling engine with a thermal buffer tube

    International Nuclear Information System (INIS)

    Yang, Qin; Luo, Ercang; Dai, Wei; Yu, Guoyao

    2012-01-01

    This article presents a modified free-piston Stirling heat engine configuration in which a thermal buffer tube is added to sandwich between the hot and cold heat exchangers. Such a modified configuration may lead to an easier fabrication and lighter weight of a free piston. To analyze the thermodynamic performance of the modified free piston Stirling heat engine, thermoacoustic theory is used. In the thermoacoustic modelling, the regenerator, the free piston, and the thermal buffer tube are given at first. Then, based on linear thermoacoustic network theory, the thermal and thermodynamic networks are presented to characterize acoustic pressure and volume flow rate distributions at different interfaces, and the global performance such as the power output, the heat input and the thermal efficiency. A free piston Stirling heat engine with several hundreds of watts mechanical power output is selected as an example. The typical operating and structure parameters are as follows: frequency around 50 Hz, mean pressure around 3.0 MPa, and a diameter of free piston around 50 mm. From the analysis, it was found that the modified free-piston Stirling heat engine has almost the same thermodynamic performance as the original design, which indicates that the modified configuration is worthy to develop in future because of its mechanical simplicity and reliability.

  5. Experimental Investigation of Bifurcations in a Thermoacoustic Engine

    OpenAIRE

    Vishnu R. Unni; Yogesh M. S. Prasaad; N. T. Ravi; S. Md Iqbal; Bala Pesala; R. I. Sujith

    2015-01-01

    In this study, variation in the characteristics of the pressure oscillations in a thermoacoustic engine is explored as the input heat flux is varied. A bifurcation diagram is plotted to study the variation in the qualitative behavior of the acoustic oscillations as the input heat flux changes. At a critical input heat flux (60 Watt), the engine begins to produce acoustic oscillations in its fundamental longitudinal mode. As the input heat flux is increased, incommensurate frequencies appear i...

  6. Measurement of Heat Flow Transmitted through a Stacked-Screen Regenerator of Thermoacoustic Engine

    Directory of Open Access Journals (Sweden)

    Shu Han Hsu

    2017-03-01

    Full Text Available A stacked-screen regenerator is a key component in a thermoacoustic Stirling engine. Therefore, the choice of suitable mesh screens is important in the engine design. To verify the applicability of four empirical equations used in the field of thermoacoustic engines and Stirling engines, this report describes the measurements of heat flow rates transmitted through the stacked screen regenerator inserted in an experimental setup filled with pressurized Argon gas having mean pressure of 0.45 MPa. Results show that the empirical equations reproduce the measured heat flow rates to a mutually similar degree, although their derivation processes differ. Additionally, results suggest that two effective pore radii would be necessary to account for the viscous and thermal behaviors of the gas oscillating in the stacked-screen regenerators.

  7. Basic treatment of onset conditions and transient effects in thermoacoustic Stirling engines

    NARCIS (Netherlands)

    Waele, de A.T.A.M.

    2009-01-01

    This paper treats the basics of thermoacoustic engines. The set of differential equations, which describes the dynamics of the individual components, is condensed in a single high-order differential equation which determines the time dependence of all dynamic variables. From this relation analytical

  8. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    Science.gov (United States)

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  9. A Generic Model for Prediction of Separation Performance of Olefin/Paraffin Mixture by Glassy Polymer Membranes

    Directory of Open Access Journals (Sweden)

    A.A. Ghoreyshi

    2008-02-01

    Full Text Available The separation of olefin/paraffin mixtures is an important process in petrochemical industries, which is traditionally performed by low temperature distillation with a high-energy consumption, or complex extractive distillationand adsorption techniques. Membrane separation process is emerging as an alternative for traditional separation processes with respect to low energy and simple operation. Investigations made by various researchers on polymeric membranes it is found that special glassy polymers render them as suitable materials for olefin/paraffin mixture separation. In this regard, having some knowledge on the possible transport mechanism of these processes would play a significant role in their design and applications. In this study, separation behavior of olefin/paraffin mixtures through glassy polymers was modeled by three different approaches: the so-called dual transport model, the basic adsorption-diffusion theory and the general Maxwell-Stefan formulation. The systems chosen to validate the developed transport models are separation of ethane-ethylene mixture by 6FDA-6FpDA polyimide membrane and propane-propylene mixture by 6FDA-TrMPD polyimide membrane for which the individual sorption and permeation data are available in the literature. Acritical examination of dual transport model shows that this model fails clearly to predict even the proper trend for selectivities. The adjustment of pemeabilities by accounting for the contribution of non-selective bulk flow in the transport model introduced no improvement in the predictability of the model. The modeling results based on the basic adsorption-diffusion theory revealed that in this approach only using mixed permeability data, an acceptable result is attainable which fades out the advantages of predictibility of multicomponent separation performance from pure component data. Finally, the results obtained from the model developed based on Maxwell-Stefan formulation approach show a

  10. Are separate-phase thermal-hydraulic models better than mixture-fluid approaches? It depends. Rather not

    International Nuclear Information System (INIS)

    Hoeld, A.

    2004-01-01

    The thermal-hydraulic theory of single- and especially two-phase flow systems used for plant transient analysis is dominated by separate-phase models. The corresponding mostly very comprehensive codes (TRAC, RELAP, CATHARE, ATHLET etc.) are looked as to be by far more efficient than a 3 eq. mixture-fluid approach and code also if they show deficiencies in describing flow situations within inner loops as for example the distribution into parallel channels (and thus the simulation of 3D thermal-hydraulic phenomena). This may be justified if comparing them to the very simple 'homogeneous equilibrium models (HEM)', but not if looking to the more refined non-homogeneous 'separate-region' mixture-fluid approaches based on appropriate drift-flux correlation packages which can have, on the contrary, enormous advantages with respect to such separate-phase models. Especially if comparing the basic (and starting) eqs. of such theoretical models of both types the differences are remarkable. Single-phase and mixture-fluid models start from genuine conservation eqs. for mass, energy and momentum, demanding (in case of two-phase flow) additionally an adequate drift flux package (in order to get a relation for a fourth independent variable), a heat transfer coefficients package (over the whole range of the possible fields of application) and correlations for single- and two-phase friction. The other types of models are looking at each phase separately with corresponding 'field' eqs. for each phase, connected by exchange (=closure) terms which substitute the classical constitutive packages for drift, heat transfer and friction. That the drift-flux, heat transfer into a coolant channel and friction along a wall and between the phases is described better by a separate-phase approach is at least doubtful. The corresponding mixture-fluid correlations are based over a wide range on a treasure of experience and measurements, their pseudo-stationary treatment can (due to their small time

  11. Methods of separating short half-life radionuclides from a mixture of radionuclides

    Science.gov (United States)

    Bray, Lane A.; Ryan, Jack L.

    1998-01-01

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of .sup.223 Ra and .sup.225 Ac, from a radionuclide "cow" of .sup.227 Ac or .sup.229 Th respectively. The method comprises the steps of a) permitting ingrowth of at least one radionuclide daughter from said radionuclide "cow" forming an ingrown mixture; b) insuring that the ingrown mixture is a nitric acid ingrown mixture; c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the "cow" from at least one radionuclide daughter; d) insuring that the at least one radionuclide daughter contains the radionuclide product; e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and f) recycling the at least one radionuclide daughter by adding it to the "cow". In one embodiment the radionuclide "cow" is the .sup.227 Ac, the at least one daughter radionuclide is a .sup.227 Th and the product radionuclide is the .sup.223 Ra and the first nitrate form ion exchange column passes the .sup.227 Ac and retains the .sup.227 Th. In another embodiment the radionuclide "cow"is the .sup.229 Th, the at least one daughter radionuclide is a .sup.225 Ra and said product radionuclide is the .sup.225 Ac and the .sup.225 Ac and nitrate form ion exchange column retains the .sup.229 Th and passes the .sup.225 Ra/Ac.

  12. Smoothed particle hydrodynamics model for phase separating fluid mixtures. I. General equations

    NARCIS (Netherlands)

    Thieulot, C; Janssen, LPBM; Espanol, P

    We present a thermodynamically consistent discrete fluid particle model for the simulation of a recently proposed set of hydrodynamic equations for a phase separating van der Waals fluid mixture [P. Espanol and C.A.P. Thieulot, J. Chem. Phys. 118, 9109 (2003)]. The discrete model is formulated by

  13. Thermodynamic analysis of onset characteristics in a miniature thermoacoustic Stirling engine

    Science.gov (United States)

    Huang, Xin; Zhou, Gang; Li, Qing

    2013-06-01

    This paper analyzes the onset characteristics of a miniature thermoacoustic Stirling heat engine using the thermodynamic analysis method. The governing equations of components are reduced from the basic thermodynamic relations and the linear thermoacoustic theory. By solving the governing equation group numerically, the oscillation frequencies and onset temperatures are obtained. The dependences of the kinds of working gas, the length of resonator tube, the diameter of resonator tube, on the oscillation frequency are calculated. Meanwhile, the influences of hydraulic radius and mean pressure on the onset temperature for different working gas are also presented. The calculation results indicate that there exists an optimal dimensionless hydraulic radius to obtain the lowest onset temperature, whose value lies in the range of 0.30-0.35 for different working gases. Furthermore, the amplitude and phase relationship of pressures and volume flows are analyzed in the time-domain. Some experiments have been performed to validate the calculations. The calculation results agree well with the experimental values. Finally, an error analysis is made, giving the reasons that cause the errors of theoretical calculations.

  14. Separation of a multicomponent mixture by gaseous diffusion: modelization of the enrichment in a capillary - application to a pilot cascade

    International Nuclear Information System (INIS)

    Doneddu, F.

    1982-01-01

    Starting from the modelization of gaseous flow in a porous medium (flow in a capillary), we generalize the law of enrichment in an infinite cylindrical capillary, established for an isotropic linear mixture, to a multicomponent mixture. A generalization is given of the notion of separation yields and characteristic pressure classically used for separations of isotropic linear mixtures. We present formulas for diagonalizing the diffusion operator, modelization of a multistage, gaseous diffusion cascade and comparison with the experimental results of a drain cascade (N 2 -SF 6 -UF 6 mixture). [fr

  15. A separation process for hydrogen fluoride from its mixtures with 1,1,1-trifluoro-2-chloroethane

    Energy Technology Data Exchange (ETDEWEB)

    Galland, J.M.; Perdriau, R.; Rouzies, D.

    1994-03-11

    When decanting the mixture of hydrogen fluoride (HF) and 1,1,1-trifluoro-2-chloroethane (F133a) at a temperature between -40 deg C and -10 deg C, a lower organic phase, poor in HF, and a superior phase, rich in HF, are obtained (the reaction may be activated with trichlorethylen); the superior phase can be directly recycled in the fluorination reactor or distilled in order to separate the HF-F133a azeotrope (the head), which is sent back to the decanter, and a quasi-pure HF (the ends). The lower phase distillation produces HF-F133a (head) and a mixture of F133a and trichlorethylen (ends); this mixture is then distilled and pure F133a is separated from trichlorethylen. 9 p., 2 fig.

  16. Detectability prediction for a thermoacoustic sensor in the breazeale nuclear reactor pool

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James [Idaho National Laboratory, Idaho Falls, ID (United States); Hrisko, Joshua [Idaho National Laboratory, Idaho Falls, ID (United States); Garrett, Steven [Idaho National Laboratory, Idaho Falls, ID (United States)

    2016-03-01

    Laboratory experiments have suggested that thermoacoustic engines can be in- corporated within nuclear fuel rods. Such engines would radiate sounds that could be used to measure and acoustically-telemeter information about the op- eration of the nuclear reactor (e.g., coolant temperature or uxes of neutrons or other energetic particles) or the physical condition of the nuclear fuel itself (e.g., changes in temperature, evolved gases) that are encoded as the frequency and/or amplitude of the radiated sound [IEEE Measurement and Instrumen- tation 16(3), 18-25 (2013)]. For such acoustic information to be detectable, it is important to characterize the vibroacoustical environments within reactors. Measurements will be presented of the background noise spectra (with and with- out coolant pumps) and reverberation times within the 70,000 gallon pool that cools and shields the fuel in the 1 MW research reactor on Penn State's campus using two hydrophones, a piezoelectric projector, and an accelerometer. Sev- eral signal-processing techniques will be demonstrated to enhance the measured results. Background vibrational measurement were also taken at the 250 MW Advanced Test Reactor, located at the Idaho National Laboratory, using ac- celerometers mounted outside the reactor's pressure vessel and on plumbing will also be presented. The detectability predictions made in the thesis were validated in September 2015 using a nuclear ssion-heated thermoacoustic sensor that was placed in the core of the Breazeale Nuclear Reactor on Penn State's campus. Some features of the thermoacoustic device used in that experiment will also be revealed. [Work supported by the U.S. Department of Energy.

  17. Method of separating (125I)-L-thyroxine from mixture obtained by radioiodination

    International Nuclear Information System (INIS)

    Mucha, J.; Talan, P.; Dobias, M.

    1982-01-01

    ( 125 I)-L-thyroxine is separated by gel filtration on a column from the mixture of ( 125 I)-L-thyroxine, ( 125 I)-L-3,5,3'-triiodothyronine and ( 125 I) - . The column is packed with a non-polar gel such as polydextran with particle size 25 to 100 μm. The mixture 1,2-propanediol/distilled water/concentrated (26%) aqueous ammonia solution, or 1,2-propanediol/concentrated (26%) aqueous ammonia solution is used as eluent. The concentration of the eluate containing ( 125 I)-L-thyroxine is adjusted with distilled water such as to establish a 50 vol.% concentration of 1,2-propanediol. (E.S.)

  18. separation of oil palm kernel and shell mixture using soil and palm

    African Journals Online (AJOL)

    user

    shape and size of the nuts and a good industrial raw material [3]. ... Large-scale mills have automated hydro-cyclone machines with high separation efficiency, however, clay-baths and hydro cyclones are known for their high energy and water consumption .... A mixture of kernel/shell weighing 20kg were poured into pot 1 ...

  19. Polyimide hollow fiber membranes for CO2 separation from wet gas mixtures

    Directory of Open Access Journals (Sweden)

    F. Falbo

    2014-12-01

    Full Text Available Matrimid®5218 hollow fiber membranes were prepared using the dry-wet spinning process. The transport properties were measured with pure gases (H2, CO2, N2, CH4 and O2 and with a mixture (30% CO2 and 70% N2 in dry and wet conditions at 25 ºC, 50 ºC, 60 ºC and 75 ºC and up to 600 kPa. Interesting values of single gas selectivity up to 60 ºC (between 31 and 28 for CO2/N2 and between 33 and 30 for CO2/CH4 in dry condition were obtained. The separation factor measured for the mixture was 20% lower compared to the single gas selectivity, in the whole temperature range analyzed. In saturation conditions the data showed that water influences the performance of the membranes, inducing a reduction of the permeance of all gases. Moreover, the presence of water caused a decrease of single gas selectivity and separation factor, although not so significant, highlighting the very high water resistance of hollow fiber membrane modules.

  20. Effect of the structured packing height on efficiency of freons mixture separation in a large-scale model of distillation column

    Directory of Open Access Journals (Sweden)

    Pavlenko Aleksandr

    2017-01-01

    Full Text Available Results of experimental studies of heat-and-mass transfer and hydrodynamic processes at distillation on a regular packing are presented. The mixture of freons R114–R21 at the pressure of 0.3 MPa was used as a working mixture. The mixture was separated on the Mellapak 350Y structured packing with the diameter of 0.9 m under the conditions of complete reflux (L/V = 1 at different packing heights. A specially designed liquid distributor with a possibility to change the density and pattern of drip points was used to irrigate the packing. The experimental data on the efficiency of mixture separation (height of transfer unit HTU and distribution of the local flow rate density over the column cross-section were compared. It is shown that an increase in the height of the structured packing from 2.1 m to 4.0 m leads to a significant decrease in the efficiency of mixture separation in the distillation column.

  1. Holographic-interferometric and thermoanemometric study of a thermoacoustic prime mover

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Wang, A. B.; Lédl, Vít; Vít, Tomáš; Chen, Y. Ch.; Maršík, František

    2013-01-01

    Roč. 29, č. 1 (2013), s. 59-66 ISSN 1727-7191 R&D Projects: GA ČR(CZ) GCP101/11/J019 Institutional research plan: CEZ:AV0Z20760514 Institutional support: RVO:61388998 ; RVO:61389021 Keywords : thermoacoustics * holographic interferometry * hot-wire anemometry Subject RIV: BJ - Thermodynamics; BJ - Thermodynamics (UFP-V) Impact factor: 0.314, year: 2013 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8832965

  2. Adsorptive separation of ethylene/ethane mixtures using carbon nanotubes: a molecular dynamics study

    International Nuclear Information System (INIS)

    Tian, Xingling; Zhou, Bo; Wang, Zhigang; Yang, Zaixing; Xiu, Peng

    2013-01-01

    Ethylene/ethane separation is a very important process in the chemical industry. Traditionally, this process is achieved by cryodistillation, which is extremely energy-intensive. The adsorptive separation is an energy-saving and environmentally benign alternative. In this study, we employ molecular dynamics simulations to study the competitive adsorption of an equimolar mixture of gaseous ethane and ethylene inside single-walled carbon nanotubes (SWNTs) of different diameters at room temperature. We find that for narrow SWNTs, i.e. the (6, 6) and (7, 7) SWNTs, the selectivities towards ethane, f selec , can reach values of 3.1 and 3.7, respectively. Such high selectivities are contrary to the opinion of many researchers that the adsorptive separation of an ethylene/ethane mixture by means of dispersion interaction is difficult due to the same carbon number of ethane and ethylene. The key for our observation is that the role of dispersion interaction of ethane's additional two hydrogen atoms with the SWNT becomes significant under extreme confinement. Interestingly, the (8, 8) SWNT prefers ethylene to ethane with f selec = 0.6. For wider SWNTs, f selec converges to ∼1. The mechanisms behind these observations, as well as the kinetics of single-file nanopore filling and kinetics of confined gas molecules are discussed. Our findings suggest that efficient ethane/ethylene separation can be achieved by using bundles/membranes of SWNTs with appropriate diameters. (paper)

  3. Investigation of a high frequency pulse tube cryocooler driven by a standing wave thermoacoustic engine

    International Nuclear Information System (INIS)

    Boroujerdi, A.A.; Ziabasharhagh, M.

    2014-01-01

    Highlights: • A nonlinear numerical model of a high frequency TADPTC has been developed. • The finite volume method has been used for discretization of governing equations. • The self-excitation process has been simulated very well. • The effects of APAT on the performance of the device have been investigated. • Lagrangian approach has been used to trace the thermodynamic cycle of gas parcels. - Abstract: In this work, a typical thermoacoustically driven pulse tube cooler as a no-moving part device has been investigated by a numerical method. A standing wave thermoacoustic engine as a prime mover in coupled with an inertance tube pulse tube cryocooler has been modeled. Nonlinear equations of unsteady one-dimensional compressible flow have been solved by the finite volume method. The model presents an important step towards the development of nonlinear simulation tools for the high amplitude thermoacoustic systems that are needed for practical use. The results of the computations show that the self-excited oscillations are well accompanied by the increasing of the pressure amplitude. The necessity of implementation of a nonlinear model to investigate such devices has been proven. The effect of APAT length as an amplifier coupler on the performance of the cooler has been investigated. Furthermore, by using Lagrangian approach, thermodynamic cycle of gas parcels has been attained

  4. Optical separation and controllable delivery of cells from particle and cell mixture

    Directory of Open Access Journals (Sweden)

    Li Yuchao

    2015-11-01

    Full Text Available Cell separation and delivery have recently gained significant attention in biological and biochemical studies. In thiswork, an optical method for separation and controllable delivery of cells by using an abruptly tapered fiber probe is reported. By launching a laser beam at the wavelength of 980 nm into the fiber, a mixture of cells with sizes of ~5 and ~3 μm and poly(methyl methacrylate particles with size of 5 μm are separated into three chains along the direction of propagation of light. The cell and particle chains are delivered in three dimensions over 600 μm distance. Experimental results are interpreted by numerical simulations. Optical forces and forward migration velocities of different particles and cells are calculated and discussed.

  5. Pervaporation separation of ethanol-water mixtures using polyethylenimine composite membranes

    Science.gov (United States)

    Neidlinger, H.H.; Schissel, P.O.; Orth, R.A.

    1985-06-19

    Synthetic, organic, polymeric membranes were prepared from polyethylenimine for use with pervaporation apparatus in the separation of ethanol-water mixtures. The polymeric material was prepared in dilute aqueous solution and coated onto a polysulfone support film, from which excess polymeric material was subsequently removed. Cross-links were then generated by limited exposure to toluene-2,4-diisocyanate solution, after which the prepared membrane was heat-cured. The resulting membrane structures showed high selectivity in permeating ethanol or water over a wide range of feed concentrations. 2 tabs.

  6. In vivo microwave-based thermoacoustic tomography of rats (Conference Presentation)

    Science.gov (United States)

    Lin, Li; Zhou, Yong; Wang, Lihong V.

    2016-03-01

    Microwave-based thermoacoustic tomography (TAT), based on the measurement of ultrasonic waves induced by microwave pulses, can reveal tissue dielectric properties that may be closely related to the physiological and pathological status of the tissues. Using microwaves as the excitation source improved imaging depth because of their deep penetration into biological tissues. We demonstrate, for the first time, in vivo microwave-based thermoacoustic imaging in rats. The transducer is rotated around the rat in a full circle, providing a full two-dimensional view. Instead of a flat ultrasonic transducer, we used a virtual line detector based on a cylindrically focused transducer. A 3 GHz microwave source with 0.6 µs pulse width and an electromagnetically shielded transducer with 2.25 MHz central frequency provided clear cross-sectional images of the rat's body. The high imaging contrast, based on the tissue's rate of absorption, and the ultrasonically defined spatial resolution combine to reveal the spine, kidney, muscle, and other deeply seated anatomical features in the rat's abdominal cavity. This non-invasive and non-ionizing imaging modality achieved an imaging depth beyond 6 cm in the rat's tissue. Cancer diagnosis based on information about tissue properties from microwave band TAT can potentially be more accurate than has previously been achievable.

  7. Separation of the components of the TBP-H2 MBP-HDBP-H3PO4 mixture

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Abrao, A.

    1981-04-01

    Several schemes for the separation of dibutylphosphoric acid (HDBP), monobutylphosphoric acid (H 2 MBP) and orthophosphoric acid (H 3 PO 4 ) as hydrolytic and radiolytic degradation products from tri-n-butylphosphate (TBP) were studied. For the resolution of a HDBP, H 2 MPB and H 3 PO 4 mixture in TBP-diluent, or in TBP-diluent-heavy metal nitrate (U-VI, Th-IV or Zr-IV), techniques such as ion exchange chromatography, ion chromatography and separation onto a chromatographic alumina column were investigated. For the identification, determination and analytical resolution following up for the several systems studied, techniques such as refraction index measurement, electrical conductivity measurement, molecular spectrophotometry and gas chromatography were applied. Special emphasys was given to the separation using alumina column where the HDBP acid was retained and eluted selectively for its separation from TBP-varsol-uranyl nitrate mixtures. This analytical procedure was applied to the samples coming from the Uranium Purification Pilot Plant in operation at the Centro de Engenharia Quimica (IPEN). (Author) [pt

  8. Separation/extraction, detection, and interpretation of DNA mixtures in forensic science (review).

    Science.gov (United States)

    Tao, Ruiyang; Wang, Shouyu; Zhang, Jiashuo; Zhang, Jingyi; Yang, Zihao; Sheng, Xiang; Hou, Yiping; Zhang, Suhua; Li, Chengtao

    2018-05-25

    Interpreting mixed DNA samples containing material from multiple contributors has long been considered a major challenge in forensic casework, especially when encountering low-template DNA (LT-DNA) or high-order mixtures that may involve missing alleles (dropout) and unrelated alleles (drop-in), among others. In the last decades, extraordinary progress has been made in the analysis of mixed DNA samples, which has led to increasing attention to this research field. The advent of new methods for the separation and extraction of DNA from mixtures, novel or jointly applied genetic markers for detection and reliable interpretation approaches for estimating the weight of evidence, as well as the powerful massively parallel sequencing (MPS) technology, has greatly extended the range of mixed samples that can be correctly analyzed. Here, we summarized the investigative approaches and progress in the field of forensic DNA mixture analysis, hoping to provide some assistance to forensic practitioners and to promote further development involving this issue.

  9. Method to separate off hydrogen fluoride from a uranium hexafluoride-hydrogen fluoride mixture

    International Nuclear Information System (INIS)

    Pfistermeister, M.; Jokar, J.

    1979-01-01

    There have been sofar difficulties involved in separating off HF when purifying UF 6 . According to the invention, this can be achieved without great expenditure if one adds a perfluorated amine or derivative of it to the UF 6 -HF mixture. The UF 6 can be separated by simple distillation or sublimation from the hardly-volatile formed tri-(perfluoro-butyl) ammonium fluoride. The adduct formed can be easily split again with NaOH so that the amine can be recycled without loss. (UWI) [de

  10. Development of a Thermoacoustic Stirling Engine Technology Demonstrator

    Science.gov (United States)

    Reissner, Alexander; Gerger, Joachim; Hummel, Stefan; Reißig, Jannis; Pawelke, Roland

    2014-08-01

    Waste heat is a primary source of energy loss in many aerospace and terrestrial applications. FOTEC, an Austrian Research Company located in Wiener Neustadt, is presently developing a micro power converter, promising high efficiencies even for small- scale applications. The converter is based on an innovative thermoacoustic stirling engine concept without any moving parts. Such a maintenance-free engine system would be particularly suitable for advanced space power systems (radioisotope, waste heat) or even within the scope of terrestrial energy harvesting. This paper will summarizes the status of our ongoing efforts on this micro power converter technology.

  11. Phase separation temperatures of a liquid mixture: Dynamic light scattering technique

    International Nuclear Information System (INIS)

    Dangudom, K.; Wongtawatnugool, C.; Lacharojana, S.

    2010-01-01

    Light scattering intensity measurements and photon correlation spectroscopy (PCS) techniques were employed in an investigation of liquid-liquid phase separation behaviour of a mixture of cyclohexane and methanol at seven different compositions. It was found that, except for one composition (29% methanol), the temperature at which the scattering intensity was a maximum did not coincide with the one where the diffusion coefficient was a minimum, as would be for the case of a vapour-liquid system. The difference may be explained in terms of the local density fluctuation and the random walk problem responsible for the peak intensity and the minimum in the diffusion coefficient, respectively. The definition of phase separation temperature, as determined from diffusion process, was also proposed in this work.

  12. Mathematical model of nonstationary hydraulic processes in gas centrifuge cascade for separation of multicomponent isotope mixtures

    OpenAIRE

    Orlov, Aleksey Alekseevich; Ushakov, Anton; Sovach, Victor

    2017-01-01

    The article presents results of development of a mathematical model of nonstationary hydraulic processes in gas centrifuge cascade for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of silicon isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary hydraulic processes in gas centrifuge cascades for separation...

  13. Adsorptive separation of xenon/krypton mixtures using a zirconium-based metal-organic framework with high hydrothermal and radioactive stabilities.

    Science.gov (United States)

    Lee, Seung-Joon; Yoon, Tae-Ung; Kim, Ah-Reum; Kim, Seo-Yul; Cho, Kyung-Ho; Hwang, Young Kyu; Yeon, Jei-Won; Bae, Youn-Sang

    2016-12-15

    The separation of xenon/krypton mixtures is important for both environmental and industrial purposes. The potential of three hydrothermally stable MOFs (MIL-100(Fe), MIL-101(Cr), and UiO-66(Zr)) for use in Xe/Kr separation has been experimentally investigated. From the observed single-component Xe and Kr isotherms, isosteric heat of adsorption (Q st o ), and IAST-predicted Xe/Kr selectivities, we observed that UiO-66(Zr) has the most potential as an adsorbent among the three candidate MOFs. We performed dynamic breakthrough experiments with an adsorption bed filled with UiO-66(Zr) to evaluate further the potential of UiO-66(Zr) for Xe/Kr separation under mixture flow conditions. Remarkably, the experimental breakthrough curves show that UiO-66(Zr) can efficiently separate the Xe/Kr mixture. Furthermore, UiO-66(Zr) maintains most of its Xe and Kr uptake capacity, as well as its crystallinity and internal surface area, even after exposure to gamma radiation (2kGy) for 7h and aging for 16 months under ambient conditions. This result indicates that UiO-66(Zr) can be considered to be a potential adsorbent for Xe/Kr mixtures under both ambient and radioactive conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Electrochemically etched nanoporous silicon membrane for separation of biological molecules in mixture

    Science.gov (United States)

    Burham, Norhafizah; Azlan Hamzah, Azrul; Yunas, Jumril; Yeop Majlis, Burhanuddin

    2017-07-01

    This paper presents a technique for separating biological molecules in mixture using nanoporous silicon membrane. Nanopores were formed using electrochemical etching process (ECE) by etching a prefabricated silicon membrane in hydrofluoric acid (HF) and ethanol, and then directly bonding it with PDMS to form a complete filtration system for separating biological molecules. Tygon S3™ tubings were used as fluid interconnection between PDMS molds and silicon membrane during testing. Electrochemical etching parameters were manipulated to control pore structure and size. In this work, nanopores with sizes of less than 50 nm, embedded on top of columnar structures have been fabricated using high current densities and variable HF concentrations. Zinc oxide was diluted with deionized (DI) water and mixed with biological molecules and non-biological particles, namely protein standard, serum albumin and sodium chloride. Zinc oxide particles were trapped on the nanoporous silicon surface, while biological molecules of sizes up to 12 nm penetrated the nanoporous silicon membrane. The filtered particles were inspected using a Zetasizer Nano SP for particle size measurement and count. The Zetasizer Nano SP results revealed that more than 95% of the biological molecules in the mixture were filtered out by the nanoporous silicon membrane. The nanoporous silicon membrane fabricated in this work is integratable into bio-MEMS and Lab-on-Chip components to separate two or more types of biomolecules at once. The membrane is especially useful for the development of artificial kidney.

  15. Evidence for phase separation of ethanol-water mixtures at the hydrogen terminated nanocrystalline diamond surface.

    Science.gov (United States)

    Janssens, Stoffel D; Drijkoningen, Sien; Saitner, Marc; Boyen, Hans-Gerd; Wagner, Patrick; Larsson, Karin; Haenen, Ken

    2012-07-28

    Interactions between ethanol-water mixtures and a hydrophobic hydrogen terminated nanocrystalline diamond surface, are investigated by sessile drop contact angle measurements. The surface free energy of the hydrophobic surface, obtained with pure liquids, differs strongly from values obtained by ethanol-water mixtures. Here, a model which explains this difference is presented. The model suggests that, due to a higher affinity of ethanol for the hydrophobic surface, when compared to water, a phase separation occurs when a mixture of both liquids is in contact with the H-terminated diamond surface. These results are supported by a computational study giving insight in the affinity and related interaction at the liquid-solid interface.

  16. Thermo-acoustical molecular interaction study in binary mixtures of glycerol and ethylene glycol

    Science.gov (United States)

    Kaur, Kirandeep; Juglan, K. C.; Kumar, Harsh

    2017-07-01

    Ultrasonic velocity, density and viscosity are measured over the entire composition range for binary liquid mixtures of glycerol (CH2OH-CHOH-CH2OH) and ethylene glycol (HOCH2CH2OH) at different temperatures and constant frequency of 2MHz using ultrasonic interferometer, specific gravity bottle and viscometer respectively. Measured experimental values are used to obtained various acoustical parameters such as adiabatic compressibility, acoustic impedance, intermolecular free length, relaxation time, ultrasonic attenuation, effective molar weight, free volume, available volume, molar volume, Wada's constant, Rao's constant, Vander Waal's constant, internal pressure, Gibb's free energy and enthalpy. The variation in acoustical parameters are interpreted in terms of molecular interactions between the components of molecules of binary liquid mixtures.

  17. Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

    Science.gov (United States)

    Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

    2017-09-21

    Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

  18. Thermoacoustic refrigerators and engines comprising cascading stirling thermodynamic units

    Science.gov (United States)

    Backhaus, Scott; Swift, Greg

    2013-06-25

    The present invention includes a thermoacoustic assembly and method for improved efficiency. The assembly has a first stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator and at least one additional heat exchanger. The first stage Stirling thermal unit is serially coupled to a first end of a quarter wavelength long coupling tube. A second stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator, and at least one additional heat exchanger, is serially coupled to a second end of the quarter wavelength long coupling tube.

  19. Evaluation of the performance of thermal diffusion column separating binary gas mixtures with continuous draw-off

    International Nuclear Information System (INIS)

    Kitamoto, Asashi; Shimizu, Masami; Takashima, Yoichi

    1977-01-01

    Advanced transport relations involving three column constants, H sup(σ), K sub(c)sup(σ) and K sub(d)sup(σ), are developed to describe the separation performance of a thermal diffusion column with continuous draw-off. These constants were related to some integral functions of velocity profile, temperature distribution, density of gas mixture and characteristic values of transport coefficients. The separation of binary gas mixture by this technique was so effective that three reasonable factors had to be introduced into the column constants in the theory. They are a circulation constant of natural convection, a definition of characteristic mean temperature and a definition of mean composition over the column. The separation performance and the column constants also varied with the distortion of velocity profile due to continuous draw-off from the top or the bottom of column. However, its effect was not large, compared with the other factors mentioned above. The theory presented here makes possible to estimate the separation performance of hot-wire type thermal diffusion column with high accuracy. (auth.)

  20. The osmotic pressure of 3He-4He mixtures along the phase separation curve

    NARCIS (Netherlands)

    van de Klundert, L.J.M.; Bos, M.R.E.; van der Meij, J.A.M.; Steffens, H.A.

    1977-01-01

    The osmotic pressure of 3He-4He mixtures was measured along the phase separation curve at temperatures up to 500 mK by balancing it with the fountain pressure of pure 4He. The usefullness of the secondary osmotic pressure thermometer was reinvestigated.

  1. The osmotic pressure of 3He-4He mixtures along the phase separation curve

    International Nuclear Information System (INIS)

    Klundert, L.J.M. van de; Bos, M.R.E.; Meij, J.A.M. van der; Steffens, H.A.

    1977-01-01

    The osmotic pressure of 3 He- 4 He mixtures was measured along the phase separation curve at temperatures up to 500 mK by balancing it with the fountain pressure of pure 4 He. The usefullness of the secondary osmotic pressure thermometer was reinvestigated. (Auth.)

  2. Experimental, theoretical and numerical interpretation of thermodiffusion separation for a non-associating binary mixture in liquid/porous layers

    International Nuclear Information System (INIS)

    Ahadi, Amirhossein; Jawad, H.; Saghir, M.Z.; Giraudet, C.; Croccolo, F.; Bataller, H.

    2014-01-01

    Thermodiffusion in a hydrocarbon binary mixture has been investigated experimentally and numerically in a liquid-porous cavity. The solutal separation of the 50% toluene and 50% n-hexane binary mixture induced by a temperature difference at atmospheric pressure has been performed in a new thermodiffusion cell. A new optimized cell design is used in this study. The inner part of the cell is a cylindrical porous medium sandwiched between two liquid layers of the same binary hydrocarbon mixture. Experimental measurement and theoretical estimation of the molecular diffusion and thermodiffusion coefficients showed a good agreement. In order to understand the different regimes occurring in the different parts of the cell, a full transient numerical simulation of the solutal separation of the binary mixture has been performed. Numerical results showed that the lighter species, which are of n-hexane migrated toward the hot surface, while the denser species, which is toluene migrated towards the cold surface. Also, it was found that a good agreement has been reached between experimental measurements and numerical calculations for the solutal separation between the hot and cold surface for different medium porosity. In addition, we used the numerical results to analyse convection and diffusion regions in the cell precisely. (authors)

  3. Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler

    International Nuclear Information System (INIS)

    Kang Huifang; Li Qing; Zhou Gang

    2009-01-01

    It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.

  4. Development of thermoacoustic engine operating by waste heat from cooking stove

    Science.gov (United States)

    Chen, B. M.; Abakr, Y. A.; Riley, P. H.; Hann, D. B.

    2012-06-01

    There are about 1.5 billion people worldwide use biomass as their primary form of energy in household cooking[1]. They do not have access to electricity, and are too remote to benefit from grid electrical supply. In many rural communities, stoves are made without technical advancements, mostly using open fires cooking stoves which have been proven to be extremely low efficiency, and about 93% of the energy generated is lost during cooking. The cooking is done inside a dwelling and creates significant health hazard to the family members and pollution to environment. SCORE (www.score.uk.com) is an international collaboration research project to design and build a low-cost, high efficiency woodstove that uses about half amount of the wood of an open wood fire, and uses the waste heat of the stove to power a thermoacoustic engine (TAE) to produce electricity for applications such as LED lighting, charging mobile phones or charging a 12V battery. This paper reviews on the development of two types of the thermoacoustic engine powered by waste heat from cooking stove which is either using Propane gas or burning of wood as a cooking energy to produce an acceptable amount of electricity for the use of rural communities.

  5. Optimization of the Nonaqueous Capillary Electrophoresis Separation of Metal Ions Using Mixture Design and Response Surface Methods

    OpenAIRE

    DEMİR, Cevdet; YÜCEL, Yasin

    2014-01-01

    Mixture experimental design was used to enhance the separation selectivity of metal ions in nonaqueous capillary electrophoresis. The separation of cations (Ag, Fe, Cr, Mn, Cd, Co, Pb, Ni, Zn and Cu) was achieved using imidazole as UV co-ion for indirect detection. Acetic acid was chosen as an electrolyte because its cathodic electroosmotic flow permits faster separation. The composition of organic solvents is important to achieve the best separation of all metal ions. Simplex latt...

  6. Process for the separation of contaminant or mixture of contaminants from a Ch4-comprising gaseous feed streem

    NARCIS (Netherlands)

    2012-01-01

    The invention provides a process for the separation of a contaminant or mixture of contaminants from a CH4-comprising gaseous feed streem, comprising the subsequent steps of: a) passing a CH4-comprising gaseous feed streem comprising the contaminant or the mixture of contaminants in to and through a

  7. Sharp separation of C2/C3 hydrocarbon mixtures by zeolitic imidazolate framework-8 (ZIF-8) membranes synthesized in aqueous solutions

    KAUST Repository

    Pan, Yichang

    2011-01-01

    Exceptional high quality ZIF-8 membranes prepared through a novel seeded growth method in aqueous solutions at near room temperature exhibit excellent separation performance for C2/C3 hydrocarbon mixtures. The separation factors for mixtures of ethane/propane, ethylene/propylene and ethylene/propane are ∼80, ∼10 and ∼167, respectively. © 2011 The Royal Society of Chemistry.

  8. Separation of Pr and Nd from La in chloride solution by extraction with a mixture of Cyanex 272 and Alamine 336

    Science.gov (United States)

    Liu, Yang; Jeon, Ho Seok; Lee, Man Seung

    2015-09-01

    The possibility of separation of Pr and Nd from La in a chloride leaching solution of monazite sand has been investigated by using a binary mixture of Cyanex 272 (bis(2,4,4-trimethylpentyl) phosphinic acid) and Alamine 336 (tri-octyl/decyl amine). The binary mixture showed synergism on the extraction of the three metals and led to an increase in the separation factor between Pr/Nd and La compared to Cyanex 272 alone. Although the addition of chloride ion into aqueous increased the extraction of the metals, this addition had negative effect on the separation of Nd/Pr and La. McCabe-Thiele diagrams for the extraction of Pr and Nd with the binary mixture were constructed. Stripping of metals from the loaded organic phase was achieved with 0.7 M HCl. The difference in the solvent extraction of the rare earth elements from chloride solution between the binary mixture and saponified extractants was also discussed.

  9. Role of functional nanoparticles to enhance the polymeric membrane performance for mixture gas separation

    NARCIS (Netherlands)

    Ingole, Pravin G.; Baig, Muhammad Irshad; Choi, Wook; An, Xinghai; Choi, Won Kil; Lee, Hyung Keun

    2017-01-01

    To improve the water vapor/gas separation the hydroxylated TiO2(OH-TiO2) nanopartilces have been synthesized and surface of polysulfone (PSf) hollow fiber membrane (HFM) has been coated as thin film nanocomposite (TFN) membranes. To remove the water vapor from mixture gas, hollow fiber membrane has

  10. Experimental evaluation of DC electric field effect on the thermoacoustic behaviour of flat premixed flames

    NARCIS (Netherlands)

    Volkov, E.N.; Kornilov, V.N.; Goey, de L.P.H.

    2013-01-01

    One promising approach to eliminate thermoacoustic instabilities in combustion appliances is the use of adaptive control of the flame/burner acoustic transfer function (TF). Application of a DC electric field (EF) as a spatially distributed, easily and quickly adjustable and low-energy method to

  11. Thermo-acoustic characterization of the burner-turbine interface in a can-annular combustor using CFD

    NARCIS (Netherlands)

    Farisco, Federica

    2016-01-01

    Thermo-acoustic instabilities in high power density gas turbine engines need to be understood to avoid unexpected shutdown events. This dissertation is focused on the combustor-turbine interaction for acoustic waves. The first part of the study is based on the acoustic reflection coefficient

  12. Extraction and Separation of Cobalt and Nickel with Extractants Cyanex 302, Cyanex 272 and Their Mixture

    Directory of Open Access Journals (Sweden)

    Lenhard, Z.

    2008-09-01

    Full Text Available The extraction and separation of cobalt(II and nickel(II from sulphate solutions with different initial volume fractions of commercial organophosphorus extractants Cyanex 302, Cyanex 272 and their mixture, in kerosene as diluent, were investigated. Prepared samples contained the mixture of cobalt(II and nickel(II in mass concentrations chosen to approximate the mass concentrations of the two metals in solutions obtained by leaching typical low-grade ores or waste materials with sulphuric acid. The experiments were carried out at two concentration ratios of nickel to cobalt(ζNi/Co, 25 and 125. The latter ratio was chosen as model for the solutions of naturally occurring ores and other materials in which the concentration of nickel is much higher than that of cobalt. In all cases, the concentration of cobalt was approximately y= 0.15 g L–1, and the concentration of nickel was approximately g= 3.80 g L–1 (at ζNi/Co = 25 and 18.80 g L–1 (at ζNi/Co = 125. Other initial values were based on conditions found to be optimal in previous investigations, and kept constant in all experiments: pH0= 8, θ0 = 25 °C, phase volume ratio organic to aqueous ψ = 1 and 0.5, contact time 2 minutes.The tested fractions of extractants (Cyanex 302 or Cyanex 272, diluted in kerosene, were j = 2.5, 5.0, 7.5 and φ = 10 %. The studies of the mixture of extractants were carried out at two sets of fractions. In the first set, the fraction of Cyanex 302 was kept at φ = 10 %, and Cyanex 272 was varied in the range φ = 2.5 –10 %. In the second set, the mass concentration of each of the two extractants was varied in the range φ = 2.5–10 % so that the total fraction of the two extractants always added up to φ= 10 %.The obtained results describe the influences of type and initial volume fraction of extractant on the separation and extraction of cobalt and nickel. Under the investigated range of conditions, Cyanex 302 outperformed Cyanex 272 in cobalt

  13. Dynamic depletion attraction between colloids suspended in a phase-separating binary liquid mixture

    International Nuclear Information System (INIS)

    Araki, Takeaki; Tanaka, Hajime

    2008-01-01

    Understanding interactions between colloids (or nanoparticles) immersed in a phase-separating binary mixture is of both fundamental and technological importance. Here we report a novel type of interparticle attractive interaction of a purely dynamic origin, which is found by a coarse-grained numerical simulation. Due to surface wetting effects, there are strong diffusion fluxes towards particles just after the initiation of phase separation of the matrix binary liquid mixture. The flux in the region between particles soon becomes weaker than that in the other regions since the depletion zones formed around particles overlap selectively between the particles. The resulting imbalance of the diffusion flux induces interparticle attractive interactions, i.e., the osmotic force pushes particles closer. We confirm that this wetting-induced 'dynamic' depletion force can be stronger than a van der Waals force and a capillary force that is induced by the interfacial tension, and thus plays a dominant role in the early stage of particle aggregation. We note that this novel interaction originating from the momentum conservation law may be generic to particles acting as diffusional sinks or sources. (fast track communication)

  14. Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions.

    Science.gov (United States)

    Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

    2017-02-20

    Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m -2 h -1 bar -1 -a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

  15. Photo polymerization-induced vertical phase separation and homeotropic alignment in liquid crystal and polymer mixtures

    International Nuclear Information System (INIS)

    Kang, Hyo; Joo, Sangwoo; Kang, Daeseung

    2012-01-01

    We presented a novel method for the homeotropic alignment of LC by using the irradiation of UV light on the LC/NOA65 mixture cell, in which the photo-initiated-polymerization-induced phase separation lowers the surface energy. When the amount of polymer content is sufficiently small, the gravel and network patterns were formed at the substrates via the vertical phase separation. We found that surface roughness plays an important role in the formation of the homeotropic alignment of LC. We also observed the alignment transition of the cells by varying the mixing ratio of LC/NOA65 or the UV radiation time. Furthermore, the present proposed method has great potential for application in display devices. For decades, studies on the alignment of liquid crystal (LC) molecules have been of significant interest due to their immediate applications for display devices and the intriguing physiochemical properties they exhibit at the surface of mixtures. Usually, homeotropic (or vertical) alignment, in which the long axes of the LC molecules are oriented in a direction perpendicular to the surface, is achieved by using surfactants such as lecithin, silanes or polyimide. Recently homeotropic alignment of liquid crystal molecules was achieved by irradiating photosensitive polymers, by doping nanoparticles into LC, by utilizing nano/micro patterns, or by incorporating self-assembled monolayers (SAMs). However, a clear understanding about the alignment mechanism is still elusive. In this paper, we report a novel method for homeotropic alignment of LC by utilizing the phase separation of LC/polymer mixtures

  16. Thermoacoustic Molecular Imaging of Small Animals

    Directory of Open Access Journals (Sweden)

    Robert A. Kruger

    2003-04-01

    Full Text Available We have designed, constructed, and tested a thermoacoustic computed tomography (TCT scanner for imaging optical absorption in small animals in three dimensions. The device utilizes pulsed laser irradiation (680–1064 nm and a unique, 128-element transducer array. We quantified the isotropic spatial resolution of this scanner to be 0.35 mm. We describe a dual-wavelength subtraction technique for isolating optical dyes with TCT. Phantom experiments demonstrate that we can detect 5 fmol of a near-infrared dye (indocyanine green, ICG in a 1-ML volume using dual-wavelength subtraction. Initial TCT imaging in phantoms and in two sacrificed mice suggests that three-dimensional, optical absorption patterns in small animals can be detected with an order of magnitude better spatial resolution and an order of magnitude better low-contrast detectability in small animals when compared to fluorescence imaging or diffusion optical tomography.

  17. Thermoacoustic tomography for an integro-differential wave equation modeling attenuation

    Science.gov (United States)

    Acosta, Sebastián; Palacios, Benjamín

    2018-02-01

    In this article we study the inverse problem of thermoacoustic tomography (TAT) on a medium with attenuation represented by a time-convolution (or memory) term, and whose consideration is motivated by the modeling of ultrasound waves in heterogeneous tissue via fractional derivatives with spatially dependent parameters. Under the assumption of being able to measure data on the whole boundary, we prove uniqueness and stability, and propose a convergent reconstruction method for a class of smooth variable sound speeds. By a suitable modification of the time reversal technique, we obtain a Neumann series reconstruction formula.

  18. Adjoint-based sensitivity analysis of low-order thermoacoustic networks using a wave-based approach

    Science.gov (United States)

    Aguilar, José G.; Magri, Luca; Juniper, Matthew P.

    2017-07-01

    Strict pollutant emission regulations are pushing gas turbine manufacturers to develop devices that operate in lean conditions, with the downside that combustion instabilities are more likely to occur. Methods to predict and control unstable modes inside combustion chambers have been developed in the last decades but, in some cases, they are computationally expensive. Sensitivity analysis aided by adjoint methods provides valuable sensitivity information at a low computational cost. This paper introduces adjoint methods and their application in wave-based low order network models, which are used as industrial tools, to predict and control thermoacoustic oscillations. Two thermoacoustic models of interest are analyzed. First, in the zero Mach number limit, a nonlinear eigenvalue problem is derived, and continuous and discrete adjoint methods are used to obtain the sensitivities of the system to small modifications. Sensitivities to base-state modification and feedback devices are presented. Second, a more general case with non-zero Mach number, a moving flame front and choked outlet, is presented. The influence of the entropy waves on the computed sensitivities is shown.

  19. Lab-on-fiber electrophoretic trace mixture separating and detecting an optofluidic device based on a microstructured optical fiber.

    Science.gov (United States)

    Yang, Xinghua; Guo, Xiaohui; Li, Song; Kong, Depeng; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2016-04-15

    We report an in-fiber integrated electrophoretic trace mixture separating and detecting an optofluidic optical fiber sensor based on a specially designed optical fiber. In this design, rapid in situ separation and simultaneous detection of mixed analytes can be realized under electro-osmotic flow in the microstructured optical fiber. To visually display the in-fiber separating and detecting process, two common fluorescent indicators are adopted as the optofluidic analytes in the optical fiber. Results show that a trace amount of the mixture (0.15 μL) can be completely separated within 3.5 min under a high voltage of 5 kV. Simultaneously, the distributed information of the separated analytes in the optical fiber can be clearly obtained by scanning along the optical fiber using a 355 nm laser. The emission from the analytes can be efficiently coupled into the inner core and guides to the remote end of the optical fiber. In addition, the thin cladding around the inner core in the optical fiber can prevent the fluorescent cross talk between the analytes in this design. Compared to previous optical fiber optofluidic devices, this device first realizes simultaneously separating treatment and the detection of the mixed samples in an optical fiber. Significantly, such an in-fiber integrated separating and detecting optofluidic device can find wide applications in various analysis fields involves mixed samples, such as biology, chemistry, and environment.

  20. Influence of thermodynamic properties of a thermo-acoustic emitter on the efficiency of thermal airborne ultrasound generation.

    Science.gov (United States)

    Daschewski, M; Kreutzbruck, M; Prager, J

    2015-12-01

    In this work we experimentally verify the theoretical prediction of the recently published Energy Density Fluctuation Model (EDF-model) of thermo-acoustic sound generation. Particularly, we investigate experimentally the influence of thermal inertia of an electrically conductive film on the efficiency of thermal airborne ultrasound generation predicted by the EDF-model. Unlike widely used theories, the EDF-model predicts that the thermal inertia of the electrically conductive film is a frequency-dependent parameter. Its influence grows non-linearly with the increase of excitation frequency and reduces the efficiency of the ultrasound generation. Thus, this parameter is the major limiting factor for the efficient thermal airborne ultrasound generation in the MHz-range. To verify this theoretical prediction experimentally, five thermo-acoustic emitter samples consisting of Indium-Tin-Oxide (ITO) coatings of different thicknesses (from 65 nm to 1.44 μm) on quartz glass substrates were tested for airborne ultrasound generation in a frequency range from 10 kHz to 800 kHz. For the measurement of thermally generated sound pressures a laser Doppler vibrometer combined with a 12 μm thin polyethylene foil was used as the sound pressure detector. All tested thermo-acoustic emitter samples showed a resonance-free frequency response in the entire tested frequency range. The thermal inertia of the heat producing film acts as a low-pass filter and reduces the generated sound pressure with the increasing excitation frequency and the ITO film thickness. The difference of generated sound pressure levels for samples with 65 nm and 1.44 μm thickness is in the order of about 6 dB at 50 kHz and of about 12 dB at 500 kHz. A comparison of sound pressure levels measured experimentally and those predicted by the EDF-model shows for all tested emitter samples a relative error of less than ±6%. Thus, experimental results confirm the prediction of the EDF-model and show that the model can

  1. Thermo-acoustic instabilities in lean premixed swirl-stabilized combustion and their link to acoustically coupled and decoupled flame macrostructures

    KAUST Repository

    Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.

    2015-01-01

    © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved. We investigate the onset of thermo-acoustic instabilities and their link to the mean flame configurations - or macrostructures - under acoustically coupled

  2. SCADA System of Physicochemical Variables in a Mixture Separator

    Directory of Open Access Journals (Sweden)

    Claudia Marcela Bustamante Álvarez

    2015-01-01

    Full Text Available This paper presents the results of a research project developed by professors from Universidad de los Llanos and Colciencias Young Researcher, whose aim is to implement the necessary instrumentation to monitor and control with a SCADA system of physicochemical variables for a mixture separation process in oily water, thereby seeking to minimize environmental damage in water sources. The project was divided into three methodological stages: the establishment of interest variables, the design and implementation of the SCADA system, and the testing for results validation. This system has sensors to capture and transfer data to a PLC (S71200 for each of the system variables such as temperature, level, flow and pH. It also has HMI interface for interacting with the system. The SCADA system greatly facilitates process monitoring and establishes the possibility of remote action, just by providing the programmable logic controller (PLC to an Ethernet network.

  3. Investigating the Effect of the Binary Mixtures Composition of Noble Gases on Their Thermodynamic and Transport Properties

    Directory of Open Access Journals (Sweden)

    S. A. Burtsev

    2015-01-01

    Full Text Available The paper presents possible application fields of the binary noble gas mixtures with low Prandtl numbers. It shows that it is expedient to select these mixtures as the working fluids for closed Brayton cycle gas-turbine installations, thermo-acoustic engines and for the gas dynamic energy separation device (Leontiev tube. As follows from the analysis, He-Ar, He-Kr, and HeXe mixtures have proven to be the most attractive choice. The paper has analyzed the calculation results for coefficient of dynamic viscosity, coefficient of thermal conductivity, and for heat capacity at constant pressure for the given mixtures in terms of mixture molecular weights at pressures of 2MPa and 7MPa and temperatures of 400 and 1200°K. According to data of experiments and calculations available in public sources published by another authors, the results are verified. It was found that at constant pressure within the examined range of parameters (i.e. pressure, temperature, mixture molecular weight the obtained heat capacity values are in good agreement with the values of the verification data. In calculating dynamic viscosity coefficient for any pressure and temperature the utilized technique provides results for He-Ar and He-Kr mixtures within the entire range of the molecular weights, which are, essentially, as good as shown by international verification techniques. However, at high pressures and low temperatures for He-Xe mixture with molecular weights close to the pure Xe the divergence was found to be as high as 25 % while for other parameter intervals under consideration and with the same mixture the difference does not exceed 10 %. A good agreement with the verification data is observed for the values of a thermal conductivity coefficient of He-Ar and He-Kr mixtures for any value of parameters, while for He-Xe mixture with molecular weights close to 60 g/mole independently of pressure the divergence can reach 30 % for 1200°K and 20 % for 400°K. It is shown

  4. A simple and sensitive separation technique of 99Mo and 99mTc from their equilibrium mixture

    International Nuclear Information System (INIS)

    Swadesh Mandal; Ajoy Mandal

    2014-01-01

    The present work describes a simple and inexpensive separation method of 99 Mo from the equilibrium mixture. The liquid-liquid extraction technique has been employed to separate 99 Mo and 99m Tc using triisooctylamine (TIOA). The 99 Mo and 99m Tc were quantitatively separated out in 2 M TIOA with tripled distilled water; 99m Tc was back extracted from TIOA organic phase to aqueous phase by 0.1 M DTPA. The species information or indirect speciation of molybdenum was also established by the extraction profile of the molybdenum. (author)

  5. Improved Separation of Complex Polycyclic Aromatic Hydrocarbon Mixtures Using Novel Column Combinations in GC×GC/ToF-MS

    Science.gov (United States)

    Manzano, Carlos; Hoh, Eunha; Simonich, Staci L. Massey

    2012-01-01

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are difficult to resolve because of the high degree of overlap in compound vapor pressures, boiling points and mass spectral fragmentation patterns. The objective of this research was to improve the separation of complex PAH mixtures (including 97 different parent, alkyl-, nitro-, oxy-, thio-, chloro-, bromo-, and high molecular weight PAHs) using GC×GC/ToF-MS by maximizing the orthogonality of different GC column combinations and improving the separation of PAHs from the sample matrix interferences, including unresolved complex mixtures (UCM). Four different combinations of non-polar, polar, liquid crystal and nano-stationary phase columns were tested. Each column combination was optimized and evaluated for orthogonality using a method based on conditional entropy that considers the quantitative peak distribution in the entire two-dimensional space. Finally, an atmospheric particulate matter with diameter column in the first dimension and a 1.2 m × 0.10 mm × 0.10 µm NSP-35 nano-stationary phase column in the second dimension. In addition, the use of this column combination in GC×GC/ToF-MS resulted in significantly shorter analysis times (176 min) for complex PAH mixtures compared to one-dimensional GC/MS (257 min), as well as potentially reduced sample preparation time. PMID:22769970

  6. Isotopic separation

    International Nuclear Information System (INIS)

    Chen, C.L.

    1979-01-01

    Isotopic species in an isotopic mixture including a first species having a first isotope and a second species having a second isotope are separated by selectively exciting the first species in preference to the second species and then reacting the selectively excited first species with an additional preselected radiation, an electron or another chemical species so as to form a product having a mass different from the original species and separating the product from the balance of the mixture in a centrifugal separating device such as centrifuge or aerodynamic nozzle. In the centrifuge the isotopic mixture is passed into a rotor where it is irradiated through a window. Heavier and lighter components can be withdrawn. The irradiated mixture experiences a large centrifugal force and is separated in a deflection area into lighter and heavier components. (UK)

  7. Zeolitic imidazolate framework membranes and methods of making and using same for separation of c2- and c3+ hydrocarbons and separation of propylene and propane mixtures

    KAUST Repository

    Lai, Zhiping

    2012-12-06

    Certain embodiments are directed to processes for fabrication of zeolitic imidazolate framework (ZIF) membranes. These ZIF membranes can be used in separating C2-hydrocarbons from C3+ hydrocarbons and propylene/propane mixtures.

  8. Zeolitic imidazolate framework membranes and methods of making and using same for separation of c2- and c3+ hydrocarbons and separation of propylene and propane mixtures

    KAUST Repository

    Lai, Zhiping; Pan, Yichang

    2012-01-01

    Certain embodiments are directed to processes for fabrication of zeolitic imidazolate framework (ZIF) membranes. These ZIF membranes can be used in separating C2-hydrocarbons from C3+ hydrocarbons and propylene/propane mixtures.

  9. Ribbon phase in a phase-separated lyotropic lamellar-sponge mixture under shear flow

    Science.gov (United States)

    Cristobal, G.; Rouch, J.; Panizza, P.; Narayanan, T.

    2001-07-01

    We report the effect of shear flow on a phase-separated system composed of lyotropic lamellar (Lα) and sponge (L3) phases in a mixture of brine, surfactant, and cosurfactant. Optical microscopy, small-angle light, and x-ray scattering measurements are consistent with the existence of a steady state made of multilamellar ribbonlike structures aligned in the flow direction. At high shear rates, these ribbonlike structures become unstable and break up into monodisperse droplets resulting in a shear-thickening transition.

  10. Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

    Science.gov (United States)

    Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

    2017-08-03

    In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

  11. Separation of molecular hydrogen isotope mixtures using zeolite NaX-3M

    International Nuclear Information System (INIS)

    Polevoj, A.S.; Yudin, I.P.

    1984-01-01

    The components of transfer unit height (TUH) at separation of the H 2 -D 2 mixture using zeolite NaX-3M in the countercurrent column are determined. It is shown that the interphase isotopic exchange in the column is limited by gaseous diffusion in sorbent primary pores. On the basis of the TUH dependence the value of the hydrogen diffusion coefficient in primary pores of NaX-3M zeolite equal at 77 K and 87.3 K, respectively, approximately 1.09x10 -15 and approximately 1.69x10 -15 m 2 /s is calculated

  12. Cryogenic separation of an oxygen-argon mixture in natural air samples for the determination of isotope and molecular ratios.

    Science.gov (United States)

    Keedakkadan, Habeeb Rahman; Abe, Osamu

    2015-04-30

    The separation and purification of oxygen-argon mixtures are critical in the high-precision analysis of Δ(17) O and δ(O2 /Ar) for geochemical applications. At present, chromatographic methods are used for the separation and purification of oxygen-argon mixtures or pure oxygen, but these methods require the use of high-purity helium as a carrier gas. Considerable interest has been expressed in the development of a helium-free cryogenic separation of oxygen-argon mixtures in natural air samples. The precise and simplified cryogenic separation of oxygen-argon mixtures from natural air samples presented here was made possible using a single 5A (30/60 mesh) molecular sieve column. The method involves the trapping of eluted gases using molecular sieves at liquid nitrogen temperature, which is associated with isotopic fractionation. We tested the proposed method for the determination of isotopic fractionations during the gas exchange between water and atmospheric air at equilibrium. The dependency of fractionation was studied at different water temperatures and for different methods of equilibration (bubbling and stirring). Isotopic and molecular fractionations during gas desorption from molecular sieves were studied for different amounts and types of molecular sieves. Repeated measurements of atmospheric air yielded a reproducibility (±SD) of 0.021 ‰, 0.044 ‰, 15 per meg and 1.9 ‰ for δ(17) O, δ(18) O, Δ(17) O and δ(O2 /Ar) values, respectively. We applied the method to determine equilibrium isotope fractionation during gas exchange between air and water. Consistent δ(18) O and Δ(17) O results were obtained with the latest two studies, whereas there was a significant difference in δ(18) O values between seawater and deionized water. We have revised a helium-free, cryogenic separation of oxygen-argon mixtures in natural air samples for isotopic and molecular ratio analysis. The use of a single 13X (1/8" pellet) molecular sieve yielded the smallest isotopic

  13. Correspondence Between Uncoupled Flame Macrostructures and Thermoacoustic Instability in Premixed Swirl-Stabilized Combustion

    KAUST Repository

    Taamallah, Soufien

    2014-06-16

    In this paper, we conduct an experimental investigation of a confined premixed swirl-stabilized dump combustor similar to those found in modern gas turbines. We operate the combustor with premixed methane-air in the lean range of equivalence ratio ϕ ∈ [0.5–0.75]. First, we observe different dynamic modes in the lean operating range, as the equivalence ratio is raised, confirming observations made previously in a similar combustor geometry but with a different fuel [1]. Next we examine the correspondence between dynamic mode transitions and changes in the mean flame configuration or macrostructure. We show that each dynamic mode is associated with a specific flame macrostructure. By modifying the combustor length without changing the underlying flow, the resonant frequencies of the geometry are altered allowing for decoupling the heat release fluctuations and the acoustic field, in a certain range of equivalence ratio. Mean flame configurations in the modified (short) combustor and for the same range of equivalence ratio are examined. It is found that not only the same sequence of flame configurations is observed in both combustors (long and short) but also that the set of equivalence ratio where transitions in the flame configuration occur is closely related to the onset of thermo-acoustic instabilities. For both combustor lengths, the flame structure changes at similar equivalence ratio whether thermo-acoustic coupling is allowed or not, suggesting that the flame configuration holds the key to understanding the onset of self-excited thermo-acoustic instability in this range. Finally, we focus on the flame configuration transition that was correlated with the onset of the first dynamically unstable mode ϕ ∈ [0.61–0.64]. Our analysis of this transition in the short, uncoupled combustor shows that it is associated with an intermittent appearance of a flame in the outer recirculation zone (ORZ). The spectral analysis of this “ORZ flame flickering”

  14. Correspondence Between Uncoupled Flame Macrostructures and Thermoacoustic Instability in Premixed Swirl-Stabilized Combustion

    KAUST Repository

    Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.

    2014-01-01

    In this paper, we conduct an experimental investigation of a confined premixed swirl-stabilized dump combustor similar to those found in modern gas turbines. We operate the combustor with premixed methane-air in the lean range of equivalence ratio ϕ ∈ [0.5–0.75]. First, we observe different dynamic modes in the lean operating range, as the equivalence ratio is raised, confirming observations made previously in a similar combustor geometry but with a different fuel [1]. Next we examine the correspondence between dynamic mode transitions and changes in the mean flame configuration or macrostructure. We show that each dynamic mode is associated with a specific flame macrostructure. By modifying the combustor length without changing the underlying flow, the resonant frequencies of the geometry are altered allowing for decoupling the heat release fluctuations and the acoustic field, in a certain range of equivalence ratio. Mean flame configurations in the modified (short) combustor and for the same range of equivalence ratio are examined. It is found that not only the same sequence of flame configurations is observed in both combustors (long and short) but also that the set of equivalence ratio where transitions in the flame configuration occur is closely related to the onset of thermo-acoustic instabilities. For both combustor lengths, the flame structure changes at similar equivalence ratio whether thermo-acoustic coupling is allowed or not, suggesting that the flame configuration holds the key to understanding the onset of self-excited thermo-acoustic instability in this range. Finally, we focus on the flame configuration transition that was correlated with the onset of the first dynamically unstable mode ϕ ∈ [0.61–0.64]. Our analysis of this transition in the short, uncoupled combustor shows that it is associated with an intermittent appearance of a flame in the outer recirculation zone (ORZ). The spectral analysis of this “ORZ flame flickering”

  15. Efficacy of Ultrasonic Homogenization in the Separation of Benzene-n-Heptane Mixture by Liquid Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.S.; Chung, T.S. [Department of Chemical Engineering, Sung Kyun Kwan University, Seoul (Korea)

    1999-04-01

    In the separation of benzene-n-heptane mixture by liquid membrane, the efficacy of ultrasonic homogenization in emulsification was studied with two anionic surfactants. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether sulfate. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether stifle. The highest value of the separation factor obtained by ultrasonic homogenization was approximately three times as large as that for triethanolamine lauryl sulfate and one and a half times as large as that for sodium polyoxyethylene(2) lauryl sulfate when the mechanical stirring was used on the same operational conditions. The lowest membrane breakup was observed when the highest value of the separation factor was achieved with sodium polyoxyethylene(2) lauryl sulfate. 14 refs., 7 figs., 1 tab.

  16. Separation of several alcohol-benzene mixtures by pervaporation through styrene graft polyethylene membranes

    International Nuclear Information System (INIS)

    Murata, Kenichi

    1989-01-01

    The permeation of pure liquids, such as methanol, ethanol, 1-propanol, 2-propanol and benzene, and the permeability and selectivity of 50 vol% binary mixtures of these alcohols and benzene were investigated by pervaporation technique. The used membranes (21%, 40%, and 72% graftings) were obtained by graft polymerization of styrene to polyethylene film (thickness 10 μm) by γ-radiation. The permeation rates of each of these alcohols and benzene were measured by pervaporation through the graft membranes. Those of these alcohols were very small as well as those through the original membrane. On the other hand, the permeabilities for benzene through the graft membranes were larger than that through the original membrane. The temperature dependence of the permeation rate for benzene was expressed by Arrhenius-type relationships, and the apparent activation energies were calculated to be 10.7 (21%), 10.2 (40%) and 10.0 (72%) kcal/mol. In the permeation of 50 vol% several alcohol-benzene mixtures, the permeabilities through the graft membranes were also larger than that through the original membrane, and increased with the grafting. The temperature dependence of the permeation for these mixtures was showed by Arrhenius relationships, and the apparent activation energies were calculated to be in the range of 8.4∼11.0 kcal/mol. The separation factors of the graft membranes calculated from composition of the permeates were always smaller than that of the original membrane, but became larger with increase of molecular volume of alcohol in alcohol-benzene mixtures. (author)

  17. Immunoassay separation technique

    International Nuclear Information System (INIS)

    1977-01-01

    A method for effecting the immunoassay of a multiplicity of samples, each possibly containing an antigen or an antibody to be assayed, is discussed. Each sample is incubated with a solution containing a detectable antigen or antibody to form a multiplicity of mixtures, each mixture containing as components antigen-antibody, non-complexed antigen and non-complexed antibody. At least one of the components of the said mixture is separated by adsorption. There after, quantity of detectable antigen or antibody is detected in one of the non-adsorbed portions of the mixture. An improvement, compared to other techniques, is the continuous and sequential separation of at least one component, which is intended to be separated from each said multiplicity of mixtures

  18. Enantiomeric Mixtures in Natural Product Chemistry: Separation and Absolute Configuration Assignment.

    Science.gov (United States)

    N L Batista, Andrea; M Dos Santos, Fernando; Batista, João M; Cass, Quezia B

    2018-02-23

    Chiral natural product molecules are generally assumed to be biosynthesized in an enantiomerically pure or enriched fashion. Nevertheless, a significant amount of racemates or enantiomerically enriched mixtures has been reported from natural sources. This number is estimated to be even larger since the enantiomeric purity of secondary metabolites is rarely checked in the natural product isolation pipeline. This latter fact may have drastic effects on the evaluation of the biological activity of chiral natural products. A second bottleneck is the determination of their absolute configurations. Despite the widespread use of optical rotation and electronic circular dichroism, most of the stereochemical assignments are based on empirical correlations with similar compounds reported in the literature. As an alternative, the combination of vibrational circular dichroism and quantum chemical calculations has emerged as a powerful and reliable tool for both conformational and configurational analysis of natural products, even for those lacking UV-Vis chromophores. In this review, we aim to provide the reader with a critical overview of the occurrence of enantiomeric mixtures of secondary metabolites in nature as well the best practices for their detection, enantioselective separation using liquid chromatography, and determination of absolute configuration by means of vibrational circular dichroism and density functional theory calculations.

  19. Thermal management of thermoacoustic sound projectors using a free-standing carbon nanotube aerogel sheet as a heat source.

    Science.gov (United States)

    Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

    2014-10-10

    Carbon nanotube (CNT) aerogel sheets produce smooth-spectra sound over a wide frequency range (1-10(5) Hz) by means of thermoacoustic (TA) sound generation. Protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features for the TA sound projector and attractive performance at needed low frequencies. Energy conversion efficiencies in air of 2% and 10% underwater, which can be enhanced by further increasing the modulation temperature. Using a developed method for accurate temperature measurements for the thin aerogel CNT sheets, heat dissipation processes, failure mechanisms, and associated power densities are investigated for encapsulated multilayered CNT TA heaters and related to the thermal diffusivity distance when sheet layers are separated. Resulting thermal management methods for high applied power are discussed and deployed to construct efficient and tunable underwater sound projector for operation at relatively low frequencies, 10 Hz-10 kHz. The optimal design of these TA projectors for high-power SONAR arrays is discussed.

  20. Thermal management of thermoacoustic sound projectors using a free-standing carbon nanotube aerogel sheet as a heat source

    International Nuclear Information System (INIS)

    Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

    2014-01-01

    Carbon nanotube (CNT) aerogel sheets produce smooth-spectra sound over a wide frequency range (1–10 5 Hz) by means of thermoacoustic (TA) sound generation. Protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features for the TA sound projector and attractive performance at needed low frequencies. Energy conversion efficiencies in air of 2% and 10% underwater, which can be enhanced by further increasing the modulation temperature. Using a developed method for accurate temperature measurements for the thin aerogel CNT sheets, heat dissipation processes, failure mechanisms, and associated power densities are investigated for encapsulated multilayered CNT TA heaters and related to the thermal diffusivity distance when sheet layers are separated. Resulting thermal management methods for high applied power are discussed and deployed to construct efficient and tunable underwater sound projector for operation at relatively low frequencies, 10 Hz–10 kHz. The optimal design of these TA projectors for high-power SONAR arrays is discussed. (paper)

  1. Separation of benzene from mixtures with water, methanol, ethanol, and acetone: highlighting hydrogen bonding and molecular clustering influences in CuBTC

    NARCIS (Netherlands)

    Gutiérrez-Sevillano, J.J.; Calero, S.; Krishna, R.

    2015-01-01

    Configurational-bias Monte Carlo (CBMC) simulations are used to establish the potential of CuBTC for separation of water/benzene, methanol/benzene, ethanol/benzene, and acetone/benzene mixtures. For operations under pore saturation conditions, the separations are in favor of molecules that partner

  2. Separation process using microchannel technology

    Science.gov (United States)

    Tonkovich, Anna Lee [Dublin, OH; Perry, Steven T [Galloway, OH; Arora, Ravi [Dublin, OH; Qiu, Dongming [Bothell, WA; Lamont, Michael Jay [Hilliard, OH; Burwell, Deanna [Cleveland Heights, OH; Dritz, Terence Andrew [Worthington, OH; McDaniel, Jeffrey S [Columbus, OH; Rogers, Jr; William, A [Marysville, OH; Silva, Laura J [Dublin, OH; Weidert, Daniel J [Lewis Center, OH; Simmons, Wayne W [Dublin, OH; Chadwell, G Bradley [Reynoldsburg, OH

    2009-03-24

    The disclosed invention relates to a process and apparatus for separating a first fluid from a fluid mixture comprising the first fluid. The process comprises: (A) flowing the fluid mixture into a microchannel separator in contact with a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the first fluid is sorbed by the sorption medium, removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing first fluid from the sorption medium and removing desorbed first fluid from the microchannel separator. The process and apparatus are suitable for separating nitrogen or methane from a fluid mixture comprising nitrogen and methane. The process and apparatus may be used for rejecting nitrogen in the upgrading of sub-quality methane.

  3. Thermophysical and sonochemical behaviour of binary mixtures of decan-1-ol with halohydrocarbons at (T = 293.15 and 313.15) K

    International Nuclear Information System (INIS)

    Bhatia, Subhash C.; Bhatia, Rachna; Dubey, Gyan P.

    2010-01-01

    Densities and ultrasonic velocities of binary mixtures of decan-1-ol with 1,2-dichloroethane, 1,2-dibromoethane, and 1,1,2,2-tetrachloroethene have been measured over the entire range of composition at T = (293.15 and 313.15) K and at atmospheric pressure. From these results, the excess molar volumes, molar free volumes, excess molar isentropic compressibilities, limiting excess partial molar volumes, and isentropic compressibilities, intermolecular free lengths, and available volumes by three methods, thermal expansion coefficients, parameters related to space-filling ability, intermolecular free lengths, and molecular radii have been calculated. The experimental ultrasonic velocities have been analyzed in terms of the ideal mixture relations of Nomoto and Van Dael, Jacobson's free length, Schaaff's collision factor, Flory's statistical, and Prigogine-Flory-Patterson theories and thermoacoustical parameters.

  4. Acoustic separation of oil droplets, colloidal particles and their mixtures in a microfluidic cell

    KAUST Repository

    Vakarelski, Ivan Uriev; Li, Erqiang; Abdel-Fattah, Amr I.; Thoroddsen, Sigurdur T

    2016-01-01

    Here we report direct macroscopic and microscopic observations of acoustic driven separation of dodecane oil droplets in water in the presence and absence of colloidal silica particles suspended in the water phase. The experiments were conducted in a simple rectangular channel glass microfluidic cell in which an ultrasound standing wave pattern was generated at 300 KHz frequency. The separation process of both oil droplets and colloidal particles inside the cell was recorded using a high-speed video camera equipped with a macro-objective lens for macroscopic observation or with a high-speed camera attached to an inverted optical microscope for a higher resolution microscopic observation. We characterize the clustering process in the case of emulsion droplets or solid colloidal particles and ultimately demonstrate the emulsion droplets separation from the solid particles in the mixtures based on their different acoustic contrast factors. Finally, we conduct proof of concept experiment to show that the same approach can be used in a continuous fluid flow process.

  5. Acoustic separation of oil droplets, colloidal particles and their mixtures in a microfluidic cell

    KAUST Repository

    Vakarelski, Ivan Uriev

    2016-06-15

    Here we report direct macroscopic and microscopic observations of acoustic driven separation of dodecane oil droplets in water in the presence and absence of colloidal silica particles suspended in the water phase. The experiments were conducted in a simple rectangular channel glass microfluidic cell in which an ultrasound standing wave pattern was generated at 300 KHz frequency. The separation process of both oil droplets and colloidal particles inside the cell was recorded using a high-speed video camera equipped with a macro-objective lens for macroscopic observation or with a high-speed camera attached to an inverted optical microscope for a higher resolution microscopic observation. We characterize the clustering process in the case of emulsion droplets or solid colloidal particles and ultimately demonstrate the emulsion droplets separation from the solid particles in the mixtures based on their different acoustic contrast factors. Finally, we conduct proof of concept experiment to show that the same approach can be used in a continuous fluid flow process.

  6. The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems

    Science.gov (United States)

    Wantha, Channarong

    2018-02-01

    This paper reports on the experimental and simulation studies of the influence of stack geometries and different mean pressures on the cold end temperature of the stack in the thermoacoustic refrigeration system. The stack geometry was tested, including spiral stack, circular pore stack and pin array stack. The results of this study show that the mean pressure of the gas in the system has a significant impact on the cold end temperature of the stack. The mean pressure of the gas in the system corresponds to thermal penetration depth, which results in a better cold end temperature of the stack. The results also show that the cold end temperature of the pin array stack decreases more than that of the spiral stack and circular pore stack geometry by approximately 63% and 70%, respectively. In addition, the thermal area and viscous area of the stack are analyzed to explain the results of such temperatures of thermoacoustic stacks.

  7. Separation of Binary Mixtures of Propylene and Propane by Facilitated Transport through Silver Incorporated Poly(Ether-Block-Amide Membranes

    Directory of Open Access Journals (Sweden)

    Surya Murali R.

    2015-02-01

    Full Text Available The separation of propylene and propane is a challenging task in petroleum refineries due to the similar molecular sizes and physical properties of two gases. Composite Poly(ether-block-amide (Pebax-1657 membranes incorporated with silver tetra fluoroborate (AgBF4 in concentrations of 0-50% of the polymer weight were prepared by solution casting and solvent evaporation technique. The membranes were characterized by Scanning Electron Microscopy (SEM, Fourier Transform InfraRed (FTIR and wide-angle X-ray Diffraction (XRD to study surface and cross-sectional morphologies, effect of incorporation on intermolecular interactions and degree of crystallinity, respectively. Experimental data was measured with an indigenously built high-pressure gas separation manifold having an effective membrane area of 42 cm2. Permeability and selectivity of membranes were determined for three different binary mixtures of propylene-propane at pressures varying in the range 2-6 bar. Selectivity of C3H6/C3H8 enhanced from 2.92 to 17.22 and 2.11 to 20.38 for 50/50 and 66/34 C3H6+C3H8 feed mixtures, respectively, with increasing loading of AgBF4. Pebax membranes incorporated with AgBF4 exhibit strong potential for the separation of C3H6/C3H8 mixtures in petroleum refineries.

  8. Flame Interactions and Thermoacoustics in Multiple-Nozzle Combustors

    Science.gov (United States)

    Dolan, Brian

    The first major chapter of original research (Chapter 3) examines thermoacoustic oscillations in a low-emission staged multiple-nozzle lean direct injection (MLDI) combustor. This experimental program investigated a relatively practical combustor sector that was designed and built as part of a commercial development program. The research questions are both practical, such as under what conditions the combustor can be safely operated, and fundamental, including what is most significant to driving the combustion oscillations in this system. A comprehensive survey of operating conditions finds that the low-emission (and low-stability) intermediate and outer stages are necessary to drive significant thermoacoustics. Phase-averaged and time-resolved OH* imaging show that dramatic periodic strengthening and weakening of the reaction zone downstream of the low-emission combustion stages. An acoustic modal analysis shows the pressure wave shapes and identifies the dominant thermoacoustic behavior as the first longitudinal mode for this combustor geometry. Finally, a discussion of the likely significant coupling mechanisms is given. Periodic reaction zone behavior in the low-emission fuel stages is the primary contributor to unsteady heat release. Differences between the fuel stages in the air swirler design, the fuel number of the injectors, the lean blowout point, and the nominal operating conditions all likely contribute to the limit cycle behavior of the low-emission stages. Chapter 4 investigates the effects of interaction between two adjacent swirl-stabilized nozzles using experimental and numerical tools. These studies are more fundamental; while the nozzle hardware is the same as the lean direct injection nozzles used in the MLDI combustion concept, the findings are generally applicable to other swirl-stabilized combustion systems as well. Much of the work utilizes a new experiment where the distance between nozzles was varied to change the level of interaction

  9. Development of a dry-mechanical procedure for separating a mixture of two non-uniform grain fractions of HTR feed and breed particles

    International Nuclear Information System (INIS)

    Hartmann, K.

    1979-05-01

    If the feed-breed-particle system is employed the Head-End of the reprocessing of HTR-fuel elements requires another separation step, the so called feed-breed separation. In this report a dry-mechanical procedure is described for separating a mixture consisting of unirradiated TRISO-feed and BISO-breed particles, matrix carbon, and broken kernels and hulls by a combination of a zigzag pneumatic classifier with a magnetic separator. The feed and breed crossover rates are less than 1 percent. Furthermore, measurements of the susceptibilities of the following materials have been carried out with the magnetic separator: unirradiated feed and breed particles and unbroken kernels, feed and breed kernels with a simulated burn-up, irradiated UO 2 -kernels (80% fifa). The results show that UO 2 -kernels keep their paramagnetic character if irradiated and that the difference between the susceptibilities of feed and breed kernels is sufficient for a complete magnetic separation. In addition, a procedure is proposed for separating a mixture of TRISO-feed and TRISO-breed particles and the average particle diameter is assessed which can be expected to give the best separation by the zigzag pneumatic classifier. (orig.) [de

  10. Synergistic extraction and separation of yttrium from heavy rare earths using mixture of sec-octylphenoxy acetic acid and bis(2,4,4-trimethylpentyl)phosphinic acid

    International Nuclear Information System (INIS)

    Sun Xiaobo; Zhao Junmei; Meng Shulan; Li Deqian

    2005-01-01

    Synergistic extraction and separation of yttrium (Y) from heavy rare earths (HRE) in chloride medium using mixture of sec-octylphenoxy acetic acid (CA-12, HA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272, HL) in n-heptane has been investigated. The synergistic enhancement coefficients, R max , were obtained for Ho 3+ (5.12), Y 3+ (5.34), Er 3+ (7.04), Tm 3+ (7.50), Yb 3+ (13.12) and Lu 3+ (17.58). The separation factors (SF) between Y 3+ and HRE were obtained, and it was found that Er 3+ would form the new complex as ErH 6 A 4 L 5 in the mixture system. A cation exchange mechanism was proposed. The equilibrium constant, formation constant and thermodynamic parameters such as ΔG = -18.48 kJ/mol, ΔH = -1.36 kJ/mol and ΔS = 0.058 kJ/mol were determined. The CA-12 and Cyanex272 mixture system showed higher extraction efficiency, larger separation factors as well as excellent stripping behaviors. The application potential of the mixture system to separate Y from HRE has been discussed

  11. Two-Microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2008-01-01

    combined, independent component analysis (ICA) and binary time–frequency (T–F) masking. By estimating binary masks from the outputs of an ICA algorithm, it is possible in an iterative way to extract basis speech signals from a convolutive mixture. The basis signals are afterwards improved by grouping...

  12. Preliminary investigation of a technique to separate fission noble metals from fission-product mixtures

    International Nuclear Information System (INIS)

    Mellinger, G.B.; Jensen, G.A.

    1982-08-01

    A variation of the gold-ore fire assay technique was examined as a method for recovering Pd, Rh and Ru from fission products. The mixture of fission product oxides is combined with glass-forming chemicals, a metal oxide such as PbO (scavenging agent), and a reducing agent such as charcoal. When this mixture is melted, a metal button is formed which extracts the noble metals. The remainder cools to form a glass for nuclear waste storage. Recovery depended only on reduction of the scavenger oxide to metal. When such reduction was achieved, no difference in noble metal recovery efficiency was found among the scavengers studied (PbO, SnO, CuO, Bi 2 O 3 , Sb 2 O 3 ). Not all reducing agents studied, however, were able to reduce all scavenger oxides to metal. Only graphite would reduce SnO and CuO and allow noble metal recovery. The scavenger oxides Sb 2 O 3 , Bi 2 O 3 , and PbO, however, were reduced by all of the reducing agents tested. Similar noble metal recovery was found with each. Lead oxide was found to be the most promising of the potential scavengers. It was reduced by all of the reducing agents tested, and its higher density may facilitate the separation. Use of lead oxide also appeared to have no deterimental effect on the glass quality. Charcoal was identified as the preferred reducing agent. As long as a separable metal phase was formed in the melt, noble metal recovery was not dependent on the amount of reducing agent and scavenger oxide. High glass viscosities inhibited separation of the molten scavenger, while low viscosities allowed volatile loss of RuO 4 . A viscosity of approx. 20 poise at the processing temperature offered a good compromise between scavenger separation and Ru recovery. Glasses in which PbO was used as the scavenging agent were homogeneous in appearance. Resistance to leaching was close to that of certain waste glasses reported in the literature. 12 figures. 7 tables

  13. Process and device for the adsorptive separation of krypton from a krypton/nitrogen gas mixture

    International Nuclear Information System (INIS)

    Ringel, H.; Messler, M.

    1985-01-01

    The gas mixture flows through an adsorption column, which is filled with a means of adsorbing Krypton and nitrogen. The adsorption column is desorbed after adsorption of the gas components by a gaseous flushing material, which flows through the adsorption column in the same direction as the gas mixture. In order to achieve a high degree of separation, the adsorption material is loaded with nitrogen and Krypton from the gas inlet, where Krypton is only absorbed over part of the length of the whole column by the adsorption material. The part of the length is such that on desorption of the adsorption column with the flushing material at first only nitrogen and later only Krypton is obtained at the outlet of the adsorption column. (Waste gas system of a reprocession plant). (orig./HP) [de

  14. Separation and recycling of nanoparticles using cloud point extraction with non-ionic surfactant mixtures.

    Science.gov (United States)

    Nazar, Muhammad Faizan; Shah, Syed Sakhawat; Eastoe, Julian; Khan, Asad Muhammad; Shah, Afzal

    2011-11-15

    A viable cost-effective approach employing mixtures of non-ionic surfactants Triton X-114/Triton X-100 (TX-114/TX-100), and subsequent cloud point extraction (CPE), has been utilized to concentrate and recycle inorganic nanoparticles (NPs) in aqueous media. Gold Au- and palladium Pd-NPs have been pre-synthesized in aqueous phases and stabilized by sodium 2-mercaptoethanesulfonate (MES) ligands, then dispersed in aqueous non-ionic surfactant mixtures. Heating the NP-micellar systems induced cloud point phase separations, resulting in concentration of the NPs in lower phases after the transition. For the Au-NPs UV/vis absorption has been used to quantify the recovery and recycle efficiency after five repeated CPE cycles. Transmission electron microscopy (TEM) was used to investigate NP size, shape, and stability. The results showed that NPs are preserved after the recovery processes, but highlight a potential limitation, in that further particle growth can occur in the condensed phases. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Numerical Predictions of Early Stage Turbulence in Oscillatory Flow across Parallel-Plate Heat Exchangers of a Thermoacoustic System

    Directory of Open Access Journals (Sweden)

    Fatimah A. Z. Mohd Saat

    2017-06-01

    Full Text Available This work focuses on the predictions of turbulent transition in oscillatory flow subjected to temperature gradients, which often occurs within heat exchangers of thermoacoustic devices. A two-dimensional computational fluid dynamics (CFD model was developed in ANSYS FLUENT and validated using the earlier experimental data. Four drive ratios (defined as maximum pressure amplitude to mean pressure were investigated: 0.30%, 0.45%, 0.65% and 0.83%. It has been found that the introduction of the turbulence model at a drive ratio as low as 0.45% improves the predictions of flow structure compared to experiments, which indicates that turbulent transition may occur at much smaller flow amplitudes than previously thought. In the current investigation, the critical Reynolds number based on the thickness of Stokes’ layer falls in the range between 70 and 100. The models tested included four variants of the RANS (Reynolds-Averaged Navier–Stokes equations: k-ε, k-ω, shear-stress-transport (SST-k-ω and transition-SST, the laminar model being used as a reference. Discussions are based on velocity profiles, vorticity plots, viscous dissipation and the resulting heat transfer and their comparison with experimental results. The SST-k-ω turbulence model and, in some cases, transition-SST provide the best fit of the velocity profile between numerical and experimental data (the value of the introduced metric measuring the deviation of the CFD velocity profiles from experiment is up to 43% lower than for the laminar model and also give the best match in terms of calculated heat flux. The viscous dissipation also increases with an increase of the drive ratio. The results suggest that turbulence should be considered when designing thermoacoustic devices even in low-amplitude regimes in order to improve the performance predictions of thermoacoustic systems.

  16. Renormalization-group study of superfluidity and phase separation of helium mixtures immersed in a disordered porous medium

    International Nuclear Information System (INIS)

    Lopatnikova, A.; Berker, A.N.

    1997-01-01

    Superfluidity and phase separation in 3 He- 4 He mixtures immersed in aerogel are studied by renormalization-group theory. The quenched disorder imposed by aerogel, both at the atomic level and at the geometric level, is included. The calculation is conducted via the coupled renormalization-group mappings, near and away from aerogel, of the quenched probability distributions of random interactions. Random-bond effects on the onset of superfluidity and random-field effects on superfluid-superfluid phase separation are seen. The quenched randomness causes the λ line of second-order phase transitions of superfluidity onset to reach zero temperature, in agreement with general predictions and experiments. The effects of the atomic and geometric randomness of aerogel are investigated separately and jointly. copyright 1997 The American Physical Society

  17. Wide angle isotope separator

    International Nuclear Information System (INIS)

    Kantrowitz, A.

    1976-01-01

    A method and apparatus is described for particle separation. The method uses a wide angle radially expanding vapor of a particle mixture. In particular, selective ionization of one isotope type in the particle mixture is produced in a multichamber separator and the ionized isotope type is accelerated out of the path of the vapor expansion for separate collection

  18. Effect of Dynamic Pressure on the Performance of Thermoacoustic Refrigerator with Aluminium (Al) Resonator

    Science.gov (United States)

    Arya, Bheemsha; Nayak, B. Ramesh; Shivakumara, N. V.

    2018-04-01

    In practice the refrigerants are being used in the conventional refrigeration system to get the required cooling effect. These refrigerants produce Chlorofluorocarbons (CFCs) and Hydro chlorofluorocarbons (HCFCs) which are highly harmful to the environment, particularly depleting of ozone layers resulting in green house emissions. In order to overcome these effects, the research needs to be focused on the development of an ecofriendly refrigeration system. The thermoacoustic refrigeration system is one among such system where the sound waves are used to compress and expand the gas particles. This study focuses on the effect of dynamic pressure on the thermoacoustic refrigerator made of aluminium with overall length of 748.82 mm, and the entire inner surface of the resonator tube was coated with 2mm thickness of polyurethane to minimize the heat losses to the atmosphere. Experiments were conducted with different stack geometries i.e. parallel plates having 0.119 mm thick with spacing between the plates maintained at 0.358 mm, 1mm diameter pipes, 2mm diameter pipes and 4 mm diameter pipes. Experiments were also conducted with different drive ratios of 0.6%, 1% and 1.6% for a constant dynamic pressure of 2 bar and 10 bar for helium and air as working medium. The results were plotted with the help of graphs, the variation of coefficient of performance (COP) and the relative coefficient of performance (COPR) for the above said conditions were calculated.

  19. Thermoacoustic instability of a laminar premixed flame in Rijke tube with a hydrodynamic region

    Science.gov (United States)

    Zhao, Dan; Chow, Z. H.

    2013-07-01

    In this work, a Rijke tube with a hydrodynamic region confined is considered to investigate its non-normality and the effect of the hydrodynamic region on the system stability behaviors. Experiments are first conducted on Rijke tubes with different lengths. It is found that the fundamental mode frequency is decreased and then increased, as the flame is placed at different axial positions at the bottom half of the tube. This trend agrees well with the prediction from the thermoacoustic model developed, of which the hydrodynamic region is modelled as an oscillating 'airplug' and the flame dynamics is captured by using classical G-equation. In addition, the flame as measured is found to respond differently to oncoming acoustic disturbances. Modal and non-modal stability analyses are then conducted to determine the eigenmode growth rate and the transient one of acoustic disturbances. The 'safest' and most 'dangerous' flame locations as defined as those corresponding to extreme eigenmode and transient growth rate are estimated, and compared with those from the model without the hydrodynamic region. In order to mitigate such detrimental oscillations, identification and mitigation algorithms are experimentally implemented on the Rijke tube. The sound pressure level is reduced by approximately 50 dB. To gain insights on the thermoacoustic system, transfer function of the actuated Rijke tube system is measured by injecting a broad-band white noise. Compared with the estimation from our model, good agreement is observed. Finally, the marginal stability regions are estimated.

  20. Balancing precision and risk: should multiple detection methods be analyzed separately in N-mixture models?

    Directory of Open Access Journals (Sweden)

    Tabitha A Graves

    Full Text Available Using multiple detection methods can increase the number, kind, and distribution of individuals sampled, which may increase accuracy and precision and reduce cost of population abundance estimates. However, when variables influencing abundance are of interest, if individuals detected via different methods are influenced by the landscape differently, separate analysis of multiple detection methods may be more appropriate. We evaluated the effects of combining two detection methods on the identification of variables important to local abundance using detections of grizzly bears with hair traps (systematic and bear rubs (opportunistic. We used hierarchical abundance models (N-mixture models with separate model components for each detection method. If both methods sample the same population, the use of either data set alone should (1 lead to the selection of the same variables as important and (2 provide similar estimates of relative local abundance. We hypothesized that the inclusion of 2 detection methods versus either method alone should (3 yield more support for variables identified in single method analyses (i.e. fewer variables and models with greater weight, and (4 improve precision of covariate estimates for variables selected in both separate and combined analyses because sample size is larger. As expected, joint analysis of both methods increased precision as well as certainty in variable and model selection. However, the single-method analyses identified different variables and the resulting predicted abundances had different spatial distributions. We recommend comparing single-method and jointly modeled results to identify the presence of individual heterogeneity between detection methods in N-mixture models, along with consideration of detection probabilities, correlations among variables, and tolerance to risk of failing to identify variables important to a subset of the population. The benefits of increased precision should be weighed

  1. Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures.

    Science.gov (United States)

    Altintas, Cigdem; Keskin, Seda

    2017-11-11

    Metal organic framework (MOF) membranes have been widely investigated for gas separation applications. Several MOFs have been recently examined for selective separation of C 2 H 6 . Considering the large number of available MOFs, it is not possible to fabricate and test the C 2 H 6 separation performance of every single MOF membrane using purely experimental methods. In this study, we used molecular simulations to assess the membrane-based C 2 H 6 /C 2 H 4 and C 2 H 6 /CH 4 separation performances of 175 different MOF structures. This is the largest number of MOF membranes studied to date for C 2 H 6 separation. We computed adsorption selectivity, diffusion selectivity, membrane selectivity and gas permeability of MOFs for C 2 H 6 /C 2 H 4 and C 2 H 6 /CH 4 mixtures. Our results show that a significant number of MOF membranes are C 2 H 6 selective for C 2 H 6 /C 2 H 4 separation in contrast to traditional nanoporous materials. Selectivity and permeability of MOF membranes were compared with other membrane materials, such as polymers, zeolites, and carbon molecular sieves. Several MOFs were identified to exceed the upper bound established for polymeric membranes and many MOF membranes exhibited higher gas permeabilities than zeolites and carbon molecular sieves. Examining the structure-performance relations of MOF membranes revealed that MOFs with cavity diameters between 6 and 9 Å, porosities lower than 0.50, and surface areas between 500-1000 m 2 g -1 have high C 2 H 6 selectivities. The results of this study will be useful to guide the experiments to the most promising MOF membranes for efficient separation of C 2 H 6 and to accelerate the development of new MOFs with high C 2 H 6 selectivities.

  2. Revisiting the difference between traveling-wave and standing-wave thermoacoustic engines - A simple analytical model for the standing-wave one

    Science.gov (United States)

    Yasui, Kyuichi; Kozuka, Teruyuki; Yasuoka, Masaki; Kato, Kazumi

    2015-11-01

    There are two major categories in a thermoacoustic prime-mover. One is the traveling-wave type and the other is the standing-wave type. A simple analytical model of a standing-wave thermoacoustic prime-mover is proposed at relatively low heat-flux for a stack much shorter than the acoustic wavelength, which approximately describes the Brayton cycle. Numerical simulations of Rott's equations have revealed that the work flow (acoustic power) increases by increasing of the amplitude of the particle velocity (| U|) for the traveling-wave type and by increasing cosΦ for the standing-wave type, where Φ is the phase difference between the particle velocity and the acoustic pressure. In other words, the standing-wave type is a phase-dominant type while the traveling-wave type is an amplitude-dominant one. The ratio of the absolute value of the traveling-wave component (| U|cosΦ) to that of the standing-wave component (| U|sinΦ) of any thermoacoustic engine roughly equals the ratio of the absolute value of the increasing rate of | U| to that of cosΦ. The different mechanism between the traveling-wave and the standing-wave type is discussed regarding the dependence of the energy efficiency on the acoustic impedance of a stack as well as that on ωτα, where ω is the angular frequency of an acoustic wave and τα is the thermal relaxation time. While the energy efficiency of the traveling-wave type at the optimal ωτα is much higher than that of the standing-wave type, the energy efficiency of the standing-wave type is higher than that of the traveling-wave type at much higher ωτα under a fixed temperature difference between the cold and the hot ends of the stack.

  3. Impact of acoustic impedance and flow resistance on the power output capacity of the regenerators in travelling-wave thermoacoustic engines

    International Nuclear Information System (INIS)

    Yu Zhibin; Jaworski, Artur J.

    2010-01-01

    This paper considers the role of acoustic impedance, flow resistance, configuration and geometrical dimensions of regenerators on the power produced in travelling-wave thermoacoustic engines. The effects are modelled assuming a pure travelling-wave and ideal gas, which allows defining a pair of dimensionless factors based on the 'net' acoustic power production. Based on the analysis provided, the acoustic power flow in the regenerators is investigated numerically. It is shown that impedance essentially reflects the proportion between the acoustic power produced from heat energy through the thermoacoustic processes and the acoustic power dissipated by viscous and thermal-relaxation effects in the regenerators. Viscous resistance of the regenerator mainly determines the magnitude of the volumetric velocity and then affects the magnitude of acoustic impedance. High impedance and high volumetric velocity are both required in the regenerators for high power engines. The results also show that the optimum transverse dimension of the gas passage exists, but depends on the local acoustic impedance. In principle, it is possible to obtain an optimum combination between these two parameters.

  4. Bayesian mixture models for source separation in MEG

    International Nuclear Information System (INIS)

    Calvetti, Daniela; Homa, Laura; Somersalo, Erkki

    2011-01-01

    This paper discusses the problem of imaging electromagnetic brain activity from measurements of the induced magnetic field outside the head. This imaging modality, magnetoencephalography (MEG), is known to be severely ill posed, and in order to obtain useful estimates for the activity map, complementary information needs to be used to regularize the problem. In this paper, a particular emphasis is on finding non-superficial focal sources that induce a magnetic field that may be confused with noise due to external sources and with distributed brain noise. The data are assumed to come from a mixture of a focal source and a spatially distributed possibly virtual source; hence, to differentiate between those two components, the problem is solved within a Bayesian framework, with a mixture model prior encoding the information that different sources may be concurrently active. The mixture model prior combines one density that favors strongly focal sources and another that favors spatially distributed sources, interpreted as clutter in the source estimation. Furthermore, to address the challenge of localizing deep focal sources, a novel depth sounding algorithm is suggested, and it is shown with simulated data that the method is able to distinguish between a signal arising from a deep focal source and a clutter signal. (paper)

  5. Basic principles of thermo-acoustic energy and temporal profile detection of microwave pulses

    CERN Document Server

    Andreev, V G; Vdovin, V A

    2001-01-01

    Basic principles of a thermo-acoustic method developed for the detection of powerful microwave pulses of nanosecond duration are discussed.A proposed method is based on the registration of acoustic pulse profile originated from the thermal expansion of the volume where microwave energy was absorbed.The amplitude of excited acoustic transient is proportional to absorbed microwave energy and its temporal profile resembles one of a microwave pulse when certain conditions are satisfied.The optimal regimes of microwave pulse energy detection and sensitivity of acoustic transient registration with piezo-transducer are discussed.It was demonstrated that profile of a microwave pulse could be detected with temporal resolution of 1 - 3 nanosecond.

  6. Dielectrophoretic separation of gaseous isotopes

    International Nuclear Information System (INIS)

    McConnell, D.B.

    1975-01-01

    Gaseous isotopes are separated from a mixture in a vertically elongated chamber by subjecting the mixture to a nonuniform transverse electric field. Dielectrophoretic separation of the isotopes is effected, producing a transverse temperature gradient in the chamber, thereby enhancing the separation by convective countercurrent flow. In the example given, the process and apparatus are applied to the production of heavy water from steam

  7. Separation of gaseous hydrogen from a water-hydrogen mixture in a fuel cell power system operating in a weightless environment

    Science.gov (United States)

    Romanowski, William E. (Inventor); Suljak, George T. (Inventor)

    1989-01-01

    A fuel cell power system for use in a weightless environment, such as in space, includes a device for removing water from a water-hydrogen mixture condensed from the exhaust from the fuel cell power section of the system. Water is removed from the mixture in a centrifugal separator, and is fed into a holding, pressure operated water discharge valve via a Pitot tube. Entrained nondissolved hydrogen is removed from the Pitot tube by a bleed orifice in the Pitot tube before the water reaches the water discharge valve. Water discharged from the valve thus has a substantially reduced hydrogen content.

  8. Reproduction of mouse-pup ultrasonic vocalizations by nanocrystalline silicon thermoacoustic emitter

    Science.gov (United States)

    Kihara, Takashi; Harada, Toshihiro; Kato, Masahiro; Nakano, Kiyoshi; Murakami, Osamu; Kikusui, Takefumi; Koshida, Nobuyoshi

    2006-01-01

    As one of the functional properties of ultrasound generator based on efficient thermal transfer at the nanocrystalline silicon (nc-Si) layer surface, its potential as an ultrasonic simulator of vocalization signals is demonstrated by using the acoustic data of mouse-pup calls. The device composed of a surface-heating thin-film electrode, an nc-Si layer, and a single-crystalline silicon (c-Si) wafer, exhibits an almost completely flat frequency response over a wide range without any mechanical surface vibration systems. It is shown that the fabricated emitter can reproduce digitally recorded ultrasonic mouse-pups vocalizations very accurately in terms of the call duration, frequency dispersion, and sound pressure level. The thermoacoustic nc-Si device provides a powerful physical means for the understanding of ultrasonic communication mechanisms in various living animals.

  9. A thermoacoustic engine capable of utilizing multi-temperature heat sources

    International Nuclear Information System (INIS)

    Qiu Limin; Wang Bo; Sun Daming; Liu Yu; Steiner, Ted

    2009-01-01

    Low-grade energy is widespread. However, it cannot be utilized with high thermal efficiency directly. Following the principle of thermal energy cascade utilization, a thermoacoustic engine (TE) with a new regenerator that can be driven by multiple heat sources at different temperature levels is proposed. Taking a regenerator that utilizes heat sources at two temperatures as an example, theoretical research has been conducted on a traveling-wave TE with the new regenerator to predict its performance. Experimental verification is also done to demonstrate the benefits of the new regenerator. Results indicate that a TE with the new regenerator utilizing additional heat at a lower temperature experiences an increase in pressure ratio, acoustic power, efficiency, and exergy efficiency with proper heat input at an appropriate temperature at the mid-heater. A regenerator that uses multi-temperature heat sources can provide a means of recovering lower grade heat.

  10. Separation of methane-nitrogen mixtures using synthesis vertically aligned carbon nanotube membranes

    Science.gov (United States)

    Gilani, Neda; Daryan, Jafar Towfighi; Rashidi, Alimorad; Omidkhah, Mohammad Reza

    2012-03-01

    In this paper, capabilities of carbon nanotube (CNT) membranes fabricated in cylindrical pores of anodic aluminum oxide (AAO) substrate to separate the binary mixtures of CH4/N2 are studied experimentally. For this purpose, the permeability and selectivity of three CNT/AAO membranes with different growth time as 6 h, 12 h and 18 h are investigated. CNTs are grown vertically through holes of AAO with average pore diameter of 45 nm by chemical vapor deposition (CVD) of acetylene gas. CNT/AAO membranes with the same CNTs' outer diameters and different inner diameters are synthesized. The AAO are characterized by SEM analysis. In addition, SEM, TEM, BET N2 adsorption analysis and Raman spectroscopy are employed to characterize aligned CNTs. Study on permeability and selectivity of membranes for three binary mixtures of CH4/N2 showed that when the CNT inner diameters are 34 nm and 24 nm, viscous flow is the governing mechanism and insignificant selectivities of 1.2-1.24 are achieved. However, the membrane with CNT inner diameter and wall thickness of 8 nm and 16 nm respectively is considerably selective for CH4 over N2. It was also found that CH4 mole fraction in the feed and upstream feed pressure have major effect on permeability and selectivity. The membrane with 18 h synthesis time showed the selectivity is in the range of 1.8-3.85. The enhancement factor for N2 single gas diffusivity was also found to be about three times larger than that predicted by Knudsen diffusion model.

  11. Method of separating short half-life radionuclides from a mixture of radionuclides

    Science.gov (United States)

    Bray, L.A.; Ryan, J.L.

    1999-03-23

    The present invention is a method of removing an impurity of plutonium, lead or a combination thereof from a mixture of radionuclides that contains the impurity and at least one parent radionuclide. The method has the steps of (a) insuring that the mixture is a hydrochloric acid mixture; (b) oxidizing the acidic mixture and specifically oxidizing the impurity to its highest oxidation state; and (c) passing the oxidized mixture through a chloride form anion exchange column whereupon the oxidized impurity absorbs to the chloride form anion exchange column and the {sup 229}Th or {sup 227}Ac ``cow`` radionuclide passes through the chloride form anion exchange column. The plutonium is removed for the purpose of obtaining other alpha emitting radionuclides in a highly purified form suitable for medical therapy. In addition to plutonium, lead, iron, cobalt, copper, uranium, and other metallic cations that form chloride anionic complexes that may be present in the mixture are removed from the mixture on the chloride form anion exchange column. 8 figs.

  12. Application of particle image velocimetry measurement techniques to study turbulence characteristics of oscillatory flows around parallel-plate structures in thermoacoustic devices

    International Nuclear Information System (INIS)

    Mao, Xiaoan; Jaworski, Artur J

    2010-01-01

    This paper describes the development of the experimental setup and measurement methodologies to study the physics of oscillatory flows in the vicinity of parallel-plate stacks by using the particle image velocimetry (PIV) techniques. Parallel-plate configurations often appear as internal structures in thermoacoustic devices and are responsible for the hydrodynamic energy transfer processes. The flow around selected stack configurations is induced by a standing acoustic wave, whose amplitude can be varied. Depending on the direction of the flow within the acoustic cycle, relative to the stack, it can be treated as an entrance flow or a wake flow. The insight into the flow behaviour, its kinematics, dynamics and scales of turbulence, is obtained using the classical Reynolds decomposition to separate the instantaneous velocity fields into ensemble-averaged mean velocity fields and fluctuations in a set of predetermined phases within an oscillation cycle. The mean velocity field and the fluctuation intensity distributions are investigated over the acoustic oscillation cycle. The velocity fluctuation is further divided into large- and small-scale fluctuations by using fast Fourier transform (FFT) spatial filtering techniques

  13. Selective separation of hydroxy polychlorinated biphenyls (HO-PCBs) by the structural recognition on the molecularly imprinted polymers: Direct separation of the thyroid hormone active analogues from mixtures

    International Nuclear Information System (INIS)

    Kubo, Takuya; Matsumoto, Hideyuki; Shiraishi, Fujio; Nomachi, Makoto; Nemoto, Koji; Hosoya, Ken; Kaya, Kunimitsu

    2007-01-01

    We developed novel separation media for hydroxy polychlorinated biphenyls (HO-PCBs) using the molecular imprinting techniques. The results of evaluation for the molecularly imprinted polymers (MIPs) by the liquid chromatography (LC) suggested that MIPs had selective separation ability for certain HO-PCB analogues. The results of the LC evaluations and molecular modeling indicated that the molecular volumes and pK a values of template molecules were related with the retention factor of HO-PCBs. Additionally, according to the detail evaluation toward the selective separation behaviors of MIPs, these HO-PCB analogues have low pK a values dependent on their chemical structures. In other words, the prepared MIPs had selective recognition ability against the analogues, which have an OH group on a phenyl carbon and two chlorine atoms on the both neighboring carbons of the carbon attached with the OH group. Moreover, these analogues may have a potential for thyroid hormone activities so that we attempted to separate these analogues directly from mixtures of HO-PCBs using a prepared MIP

  14. Thermoacoustic CT of the breast: pilot study observations

    Science.gov (United States)

    Kruger, Robert A.; Kiser, William L., Jr.; Romilly, A. P.; Scmidt, Phyllis

    2001-06-01

    In order to assess the potential clinical utility of using thermoacoustic computer tomography (TCT) to image the breast, we conducted a retrospective pilot study of 78 patients. We recruited patients in three age groups (50 years). The study population was further segregated into normal and suspicious based on the results of the previous x-ray mammography and ultrasound. Image quality was evaluated qualitatively by consensus of two trained mammographers using a 4-point scale. The appearance of normal anatomy, cysts, benign disease and cancer was noted. Patients were also asked to rate the comfort of the TCT exam and to indicate a personal preference for x-ray mammography or TCT. Analysis of the data indicated that TCT image quality was dependent upon both patient age and breast density, improving with both increasing breast density and decreasing patient age. Fibrocystic disease was well seen, cysts appearing as areas of low RF absorption. Fibroadenomas did not demonstrate contrast enhancement with the exception of one patient with associated atypical hyperplasia. Cancer displayed higher RF absorption than surrounding tissues in 4/7 patients in whom cancer was confirmed, including one patient with a 7-mm ductal carcinoma in situ (DCIS).

  15. Argentation gas chromatography revisited: Separation of light olefin/paraffin mixtures using silver-based ionic liquid stationary phases.

    Science.gov (United States)

    Nan, He; Zhang, Cheng; Venkatesh, Amrit; Rossini, Aaron J; Anderson, Jared L

    2017-11-10

    Silver ion or argentation chromatography utilizes stationary phases containing silver ions for the separation of unsaturated compounds. In this study, a mixed-ligand silver-based ionic liquid (IL) was evaluated for the first time as a gas chromatographic (GC) stationary phase for the separation of light olefin/paraffin mixtures. The selectivity of the stationary phase toward olefins can be tuned by adjusting the ratio of silver ion and the mixed ligands. The maximum allowable operating temperature of these stationary phases was determined to be between 125°C and 150°C. Nuclear magnetic resonance (NMR) spectroscopy was used to characterize the coordination behavior of the silver-based IL as well as provide an understanding into the retention mechanism of light olefins. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Broadband Spectroscopic Thermoacoustic Characterization of Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Daniel R. Bauer

    2015-01-01

    Full Text Available Carbon nanotubes have attracted interest as contrast agents for biomedical imaging because they strongly absorb electromagnetic radiation in the optical and microwave regions. This study applies thermoacoustic (TA imaging and spectroscopy to measure the frequency-dependent absorption profile of single-walled carbon nanotubes (SWNT in the ranges of 2.7–3.1 GHz and 7–9 GHz using two tunable microwave sources. Between 7 and 9 GHz, the peak TA signal for solutions containing semiconducting and metallic SWNTs increased monotonically with a slope of 1.75 AU/GHz (R2=0.95 and 2.8 AU/GHz (R2=0.93, respectively, relative to a water baseline. However, after compensating for the background signal from water, it was revealed that the TA signal from metallic SWNTs increased exponentially within this frequency band. Results suggest that TA imaging and spectroscopy could be a powerful tool for quantifying the absorption properties of SWNTs and optimizing their performance as contrast agents for imaging or heat sources for thermal therapy.

  17. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, S.; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious represent......The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: ’Are we actually dealing with a convolutive mixture?’. We try to answer this question for EEG data....

  18. Vortical flow structure of thermoacoustic oscillations in a closed tube

    International Nuclear Information System (INIS)

    Ishii, Katsuya; Kitagawa, Shyun; Ishigaki, Masahiro; Adachi, Shizuko

    2014-01-01

    Spontaneous thermoacoustic oscillations of a gas in a closed cylindrical tube are studied. Numerical simulations of the flow field in the tube on which a temperature gradient along the axis is imposed are performed by solving the axisymmetric compressible Navier–Stokes equations. The wall temperature of the hot part near both ends (300 K) and that of the cold part near the center (20 K) are fixed. The computations are done for various values of the length ratio ξ of the hot part to the cold part between 0.3 and 1.0, and steady oscillatory states are obtained. These states are divided into three groups according to the magnitude of the pressure amplitude. The state in each group has distinguished features of the flow field. We analyze the effect of vortices on the structure of the temperature distribution. The difference of the boundary layer thickness between the hot part and the cold part is shown to play an important role. (paper)

  19. Vortical flow structure of thermoacoustic oscillations in a closed tube

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Katsuya [Information Technology Center, Nagoya University, Furou-chou, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Kitagawa, Shyun [Department of Computational Science and Engineering, Graduate School of Engineering, Nagoya University, Furou-chou, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Ishigaki, Masahiro [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Adachi, Shizuko, E-mail: ishii@cc.nagoya-u.ac.jp [School of Business and Commerce, Tokyo International University, Matoba-kita, Kawagoe-shi, Saitama 350-1197 (Japan)

    2014-12-01

    Spontaneous thermoacoustic oscillations of a gas in a closed cylindrical tube are studied. Numerical simulations of the flow field in the tube on which a temperature gradient along the axis is imposed are performed by solving the axisymmetric compressible Navier–Stokes equations. The wall temperature of the hot part near both ends (300 K) and that of the cold part near the center (20 K) are fixed. The computations are done for various values of the length ratio ξ of the hot part to the cold part between 0.3 and 1.0, and steady oscillatory states are obtained. These states are divided into three groups according to the magnitude of the pressure amplitude. The state in each group has distinguished features of the flow field. We analyze the effect of vortices on the structure of the temperature distribution. The difference of the boundary layer thickness between the hot part and the cold part is shown to play an important role. (paper)

  20. Closed compact Taylor's droplets in a phase-separated lamellar-sponge mixture under shear flow

    Science.gov (United States)

    Courbin, L.; Cristobal, G.; Rouch, J.; Panizza, P.

    2001-09-01

    We have studied by optical microscopy, small-angle light scattering, and rheology, the behavior under shear flow of a phase-separated lamellar-sponge (Lα - L3) ternary mixture. We observe in the Lα-rich region (ΦLα > 80%) the existence of a Newtonian assembly made of closed compact monodisperse lamellar droplets immersed in the sponge phase. Contrary to the classical onion glassy texture obtained upon shearing Lα phases, the droplet size scales herein as dot gamma-1, the inverse of the shear rate. This result is in good agreement with Taylor's picture. Above a critical shear rate, dot gammac, the droplets organize to form a single colloidal crystal whose lattice size varies as dot gamma-1/3. To the memory of Tess Melissa P.

  1. TU-FG-BRB-09: Thermoacoustic Range Verification with Perfect Co-Registered Overlay of Bragg Peak onto Ultrasound Image

    Energy Technology Data Exchange (ETDEWEB)

    Patch, S; Kireeff Covo, M; Jackson, A; Qadadha, Y; Campbell, K; Albright, R; Bloemhard, P; Donoghue, A; Siero, C; Gimpel, T; Small, S; Ninemire, B; Johnson, M; Phair, L [Lawrence Berkeley National Lab, Berkeley, CA (United States)

    2016-06-15

    Purpose: The potential of particle therapy has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying thermoacoustic localization of the Bragg peak onto an ultrasound image. Methods: Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the inflector of the 88″ cyclotron at Lawrence Berkeley National Lab. 2 Gy were delivered in 2 µs by a beam with peak current of 2 µA. Thermoacoustic emissions were detected by a cardiac array and Verasonics V1 ultrasound system, which also generated a grayscale ultrasound image. 1024 thermoacoustic pulses were averaged before filtering and one-way beamforming focused signal onto the Bragg peak location with perfect co-registration to the ultrasound images. Data was collected in a room temperature water bath and gelatin phantom with a cavity designed to mimic the intestine, in which gas pockets can displace the Bragg peak. Experiments were performed with the cavity both empty and filled with olive oil. Results: In the waterbath overlays of the Bragg peak agreed with Monte Carlo simulations to within 800±170 µm. Agreement within 1.3 ± 0.2 mm was achieved in the gelatin phantom, although relative stopping powers were estimated only to first order from CT scans. Protoacoustic signals were detected after travel from the Bragg peak through 29 mm and 65 mm of phantom material when the cavity was empty and full of olive oil, respectively. Conclusion: Protoacoustic range verification is feasible with a commercial clinical ultrasound array, but at doses exceeding the clinical realm. Further optimization of both transducer array and injection line chopper is required to enable range verification within a 2 Gy dose limit, which would enable online adaptive treatment. This work was supported in part by a UWM Intramural Instrumentation Grant and by the Director, Office

  2. Microphase Separation in Oil-Water Mixtures Containing Hydrophilic and Hydrophobic Ions

    NARCIS (Netherlands)

    Tasios, Nikos; Samin, Sela; van Roij, Rene; Dijkstra, Marjolein

    2017-01-01

    We develop a lattice-based Monte Carlo simulation method for charged mixtures capable of treating dielectric heterogeneities. Using this method, we study oil-water mixtures containing an antagonistic salt, with hydrophilic cations and hydrophobic anions. Our simulations reveal several phases with a

  3. Gas-chromatographic separation of hydrogen isotopes mixtures on capillary molecular sieve 5 A column at 173 K

    International Nuclear Information System (INIS)

    Bidica, N.; Preda, A.; Stanciu, V.

    2002-01-01

    Analysis of a gas mixture of hydrogen species, is not too easy because the differences in their physical-chemical properties are very small; the most different are their masses, and consequently most common analytical method appear to be the mass-spectrometry. However, the impossibility to distinguish between two ions (atomic or molecular) with the same mass renders this method as unapplicable. Another problem is the decay of tritium with production of 3 He. These disadvantages of mass-spectrometry have made that other analytical methods, like gas chromatography, to be considered and developed. Thus, there are many papers about various chromatographic columns especially prepared for hydrogen species separation but the preparation and treatment of these columns are very difficult to reproduce. Besides these, there are two other main disadvantages: column operating temperature is very low and long retention times for hydrogen species (more than half an hour) are required. However, the gas-chromatography method still remains an appropriate one. The method described in this paper was based on using a capillary molecular sieve 5A column which has been operated for this kind of separation. The retention times were relatively short, about 8-9 minutes. The carrier gas was Ne and the detector - TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. The results demonstrated a quite good efficiency for H 2 , HD, D 2 and a not very good one for orthoH 2 -paraH 2 . (authors)

  4. Process for separating radioactive gases

    International Nuclear Information System (INIS)

    Kimura, Shigeru; Awada, Yoshihisa.

    1976-01-01

    Object: To efficiently and safely separate and recover raw gases such as krypton which requires radioactive attenuation by a long term storage. Structure: A mixture of krypton and xenon is separated by liquefaction from raw gases at a first distillation column, using latent heat of liquid nitrogen. The krypton and xenon mixture separated by liquefaction at the first distillation column is separated into krypton and xenon, by controlling operation pressure of a second distillation column at about 3 - 5 atm., using sensible heat of low temperature nitrogen gas discharged from a top of the first distillation column and a condenser. (Aizawa, K.)

  5. Identification of flame transfer functions in the presence of intrinsic thermoacoustic feedback and noise

    Science.gov (United States)

    Jaensch, Stefan; Merk, Malte; Emmert, Thomas; Polifke, Wolfgang

    2018-05-01

    The Large Eddy Simulation/System Identification (LES/SI) approach is a general and efficient numerical method for deducing a Flame Transfer Function (FTF) from the LES of turbulent reacting flow. The method may be summarised as follows: a simulated flame is forced with a broadband excitation signal. The resulting fluctuations of the reference velocity and of the global heat release rate are post-processed via SI techniques in order to estimate a low-order model of the flame dynamics. The FTF is readily deduced from the low-order model. The SI method most frequently applied in aero- and thermo-acoustics has been Wiener-Hopf Inversion (WHI). This method is known to yield biased estimates in situations with feedback, thus it was assumed that non-reflective boundary conditions are required to generate accurate results with the LES/SI approach. Recent research has shown that the FTF is part of the so-called Intrinsic ThermoAcoustic (ITA) feedback loop. Hence, identifying an FTF from a compressible LES is always a closed-loop problem, and consequently one should expect that the WHI would yield biased results. However, several studies proved that WHI results compare favourably with validation data. To resolve this apparent contradiction, a variety of identification methods are compared against each other, including models designed for closed-loop identification. In agreement with theory, we show that the estimate given by WHI does not converge to the actual FTF. Fortunately, the error made is small if excitation amplitudes can be set such that the signal-to-noise ratio is large, but not large enough to trigger nonlinear flame dynamics. Furthermore, we conclude that non-reflective boundary conditions are not essentially necessary to apply the LES/SI approach.

  6. Process for the separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen-mixture

    International Nuclear Information System (INIS)

    Mandrin, Ch.

    1986-01-01

    A multistage process for separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen mixture. In a first stage isotopic exchange takes place between water containing deuterium and tritium, and ammonia depleted in deuterium and tritium. The molar ammonia throughput is chosen to be greater than two third of the molar throughput of water. The advantage of the process consists in the fact that the main product is water almost entirely free from deuterium and tritium. The byproducts are compounds enriched in deuterium and tritium, and nitrogen enriched in N-15

  7. Thermophysical properties of binary mixtures of {ionic liquid 2-hydroxy ethylammonium acetate + (water, methanol, or ethanol)}

    International Nuclear Information System (INIS)

    Alvarez, Victor H.; Mattedi, Silvana; Martin-Pastor, Manuel; Aznar, Martin; Iglesias, Miguel

    2011-01-01

    Research highlights: → This paper reports the density and speed of sound data of binary mixtures {2-hydroxy ethylammonium acetate + (water, or methanol, or ethanol)} measured between the temperatures (298.15 and 313.15) K at atmospheric pressure. → The aggregation, dynamic behavior, and hydrogen-bond network were studied using thermo-acoustic, X-ray, and NMR techniques. → The Peng-Robinson equation of state, coupled with the Wong-Sandler mixing rule using the COSMO-SAC model predicted the density of the solutions with relative mean deviations below than 3.0%. - Abstract: In this work, density and speed of sound data of binary mixtures of an ionic liquid consisting of {2-hydroxy ethylammonium acetate (2-HEAA) + (water, methanol, or ethanol)} have been measured throughout the entire concentration range, from the temperature of (288.15 to 323.15) K at atmospheric pressure. The excess molar volumes, variations of the isentropic compressibility, the apparent molar volume, isentropic apparent molar compressibility, and thermal expansion coefficient were calculated from the experimental data. The excess molar volumes were negative throughout the whole composition range. Compressibility data in combination with low angle X-ray scattering and NMR measurements proved that the presence of micelles formed due to ion pair interaction above a critical concentration of the ionic liquid in the mixtures. The Peng-Robinson equation of state coupled with the Wong-Sandler mixing rule and COSMO-SAC model was used to predict densities and the calculated deviations were lower than 3%, for binary mixtures in all composition range.

  8. High capacity Venturi scrubber to separate aerosol-borne radioactivity from an air-gas-steam mixture. Final report

    International Nuclear Information System (INIS)

    Mayinger, F.; Glueckert, U.

    1993-01-01

    All German LWR are equipped with devices which in the case of a hypothetic accident permit a filtered depressurization of the containment precluding failure of the latter and minimizing the release of radioactive materials into the environment. To filter the aerosol charged air-steam mixture from the containment also a venturi scrubber is used. It has the great advantage that it can remove safely and over a certain period of time, even without active cooling systems, the after-heat released from the separated radioactive materials. Those separated radioactive materials are trapped in a scrubbing liquid which, in the event of a temporary failure of all active cooling systems, may partly evaporate and thus remove the heat in a completely passive way. The venturi scrubbers conceived earlier by the reactor manufacturer are of a very simple design and not optimized to achieve highest separation degrees. Therefore development work was started to optimize the separation behaviour of the venturi scrubber precisely with regard to submicron aerosols which are to be expected after a core meltdown accident. To achieve this, a special concept of scrubbing liquid addition developed by the contractor, the so-called multistage concept, was applied adapting it to the specific requirements. (orig./HP) [de

  9. Analysis of Thermo-Acoustic Emission from Damage in Composite Laminates under Thermal Cyclic Loading

    International Nuclear Information System (INIS)

    Kim, Young Bok; Min, Dae Hong; Lee, Deok Bo; Choi, Nak Sam

    2001-01-01

    An investigation on nondestructive evaluation of thermal stress-reduced damage in the composite laminates (3mm in thickness and [+45 6 /-45 6 ] S lay-up angles) has been performed using the thermo-acoustic emission technique. Reduction of thermo-AE events due to repetitive thermal load cycles showed a Kaiser effect. An analysis of the thermo-AE behavior determined the stress free temperature of composite laminates. Fiber fracture and matrix cracks were observed using the optical microscopy, scanning electron microscopy and ultrasonic C-sean. Short-Time Fourier Transform of thermo-AE signals offered the time-frequency characteristics which might classify the thermo-AE as three different types to estimate the damage processes of the composites

  10. Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units

    KAUST Repository

    Yao, Zizhu; Zhang, Zhangjing; Liu, Lizhen; Li, Ziyin; Zhou, Wei; Zhao, Yunfeng; Han, Yu; Chen, Banglin; Krishna, Rajamani; Xiang, Shengchang

    2016-01-01

    Acetylene separation is a very important but challenging industrial separation task. Here, through the solvothermal reaction of CuI and 5-triazole isophthalic acid in different solvents, two metal-organic frameworks (MOFs, FJU-21 and FJU-22) with open O donor sites and controllable robustness have been obtained for acetylene separation. They contain the same paddle-wheel {Cu2(COO2)4} nodes and metal-ligand connection modes, but with different helical chains as secondary building units (SBUs), leading to different structural robustness for the MOFs. FJU-21 and FJU-22 are the first examples in which the MOFs' robustness is controlled by adjusting the helical chain SBUs. Good robustness gives the activated FJU-22 a, which has higher surface area and gas uptakes than the flexible FJU-21 a. Importantly, FJU-22 a shows extraordinary separation of acetylene mixtures under ambient conditions. The separation capacity of FJU-22 a for 50:50 C2H2/CO2 mixtures is about twice that of the high-capacity HOF-3, and its actual separation selectivity for C2H2/C2H4 mixtures containing 1 % acetylene is the highest among reported porous materials. Based on first-principles calculations, the extraordinary separation performance of C2H2 for FJU-22 a was attributed to hydrogen-bonding interactions between the C2H2 molecules with the open O donors on the wall, which provide better recognition ability for C2H2 than other functional sites, including open metal sites and amino groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units

    KAUST Repository

    Yao, Zizhu

    2016-03-02

    Acetylene separation is a very important but challenging industrial separation task. Here, through the solvothermal reaction of CuI and 5-triazole isophthalic acid in different solvents, two metal-organic frameworks (MOFs, FJU-21 and FJU-22) with open O donor sites and controllable robustness have been obtained for acetylene separation. They contain the same paddle-wheel {Cu2(COO2)4} nodes and metal-ligand connection modes, but with different helical chains as secondary building units (SBUs), leading to different structural robustness for the MOFs. FJU-21 and FJU-22 are the first examples in which the MOFs\\' robustness is controlled by adjusting the helical chain SBUs. Good robustness gives the activated FJU-22 a, which has higher surface area and gas uptakes than the flexible FJU-21 a. Importantly, FJU-22 a shows extraordinary separation of acetylene mixtures under ambient conditions. The separation capacity of FJU-22 a for 50:50 C2H2/CO2 mixtures is about twice that of the high-capacity HOF-3, and its actual separation selectivity for C2H2/C2H4 mixtures containing 1 % acetylene is the highest among reported porous materials. Based on first-principles calculations, the extraordinary separation performance of C2H2 for FJU-22 a was attributed to hydrogen-bonding interactions between the C2H2 molecules with the open O donors on the wall, which provide better recognition ability for C2H2 than other functional sites, including open metal sites and amino groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Experimental and Numerical Investigation of Thermoacoustic Sources Related to High-Frequency Instabilities

    Directory of Open Access Journals (Sweden)

    Mathieu Zellhuber

    2014-03-01

    Full Text Available Flame dynamics related to high-frequency instabilities in gas turbine combustors are investigated using experimental observations and numerical simulations. Two different combustor types are studied, a premix swirl combustor (experiment and a generic reheat combustor (simulation. In both cases, a very similar dynamic behaviour of the reaction zone is observed, with the appearance of transverse displacement and coherent flame wrinkling. From these observations, a model for the thermoacoustic feedback linked to transverse modes is proposed. The model splits heat release rate fluctuations into distinct contributions that are related to flame displacement and variations of the mass burning rate. The decomposition procedure is applied on the numerical data and successfully verified by comparing a reconstructed Rayleigh index with the directly computed value. It thus allows to quantify the relative importance of various feedback mechanisms for a given setup.

  13. System Identification and Resonant Control of Thermoacoustic Engines for Robust Solar Power

    Directory of Open Access Journals (Sweden)

    Boe-Shong Hong

    2015-05-01

    Full Text Available It was found that thermoacoustic solar-power generators with resonant control are more powerful than passive ones. To continue the work, this paper focuses on the synthesis of robustly resonant controllers that guarantee single-mode resonance not only in steady states, but also in transient states when modelling uncertainties happen and working temperature temporally varies. Here the control synthesis is based on the loop shifting and the frequency-domain identification in advance thereof. Frequency-domain identification is performed to modify the mathematical modelling and to identify the most powerful mode, so that the DSP-based feedback controller can online pitch the engine to the most powerful resonant-frequency robustly and accurately. Moreover, this paper develops two control tools, the higher-order van-der-Pol oscillator and the principle of Dynamical Equilibrium, to assist in system identification and feedback synthesis, respectively.

  14. Isotopic analysis of H2, HD, D2 mixtures and analysis of ortho-para-hydrogen mixtures by gas chromatography

    International Nuclear Information System (INIS)

    Botter, F.; Perriere, G. de la; Tistchenko, S.

    1961-01-01

    This communication describes the present situation concerning the possibilities of vapor phase chromatography for the separation and analysis of mixtures of H 2 , HD and D 2 and of ortho- and para-hydrogen mixtures. Separation factors for physical adsorption of the various varieties of hydrogen have been deduced from chromatograms and have also been measured directly with a static method - the agreements is good. (author) [fr

  15. Process for separating nitrogen from methane using microchannel process technology

    Science.gov (United States)

    Tonkovich, Anna Lee [Marysville, OH; Qiu, Dongming [Dublin, OH; Dritz, Terence Andrew [Worthington, OH; Neagle, Paul [Westerville, OH; Litt, Robert Dwayne [Westerville, OH; Arora, Ravi [Dublin, OH; Lamont, Michael Jay [Hilliard, OH; Pagnotto, Kristina M [Cincinnati, OH

    2007-07-31

    The disclosed invention relates to a process for separating methane or nitrogen from a fluid mixture comprising methane and nitrogen, the process comprising: (A) flowing the fluid mixture into a microchannel separator, the microchannel separator comprising a plurality of process microchannels containing a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the methane or nitrogen is sorbed by the sorption medium, and removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing the methane or nitrogen from the sorption medium and removing the desorbed methane or nitrogen from the microchannel separator. The process is suitable for upgrading methane from coal mines, landfills, and other sub-quality sources.

  16. Separation process for boron isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rockwood, S D

    1975-06-12

    The method according to the invention is characterized by the steps of preparing a gaseous mixture of BCl/sub 3/ containing the isotopes of boron and oxygen as the extractor, irradiating that mixture in the tube of the separator device by means of P- or R-lines of a CO/sub 2/ laser for exciting the molecules containing a given isotope of boron, simultaneously irradiating the mixture with UV for photodissociating the excited BCl/sub 3/ molecules and separating BCl/sub 3/ from the reaction products of photodissociation and from oxygen. Such method is suitable for preparing boron used in nuclear reactors.

  17. Experimental investigation on preconditioned rate induced tipping in a thermoacoustic system.

    Science.gov (United States)

    Tony, J; Subarna, S; Syamkumar, K S; Sudha, G; Akshay, S; Gopalakrishnan, E A; Surovyatkina, E; Sujith, R I

    2017-07-14

    Many systems found in nature are susceptible to tipping, where they can shift from one stable dynamical state to another. This shift in dynamics can be unfavorable in systems found in various fields ranging from ecology to finance. Hence, it is important to identify the factors that can lead to tipping in a physical system. Tipping can mainly be brought about by a change in parameter or due to the influence of external fluctuations. Further, the rate at which the parameter is varied also determines the final state that the system attains. Here, we show preconditioned rate induced tipping in experiments and in a theoretical model of a thermoacoustic system. We provide a specific initial condition (preconditioning) and vary the parameter at a rate higher than a critical rate to observe tipping. We find that the critical rate is a function of the initial condition. Our study is highly relevant because the parameters that dictate the asymptotic behavior of many physical systems are temporally dynamic.

  18. Apparatus for the separation of water from water-steam mixtures

    International Nuclear Information System (INIS)

    Judith, H.; Schwerdtner, O. von.

    1975-01-01

    Steam flowing from the high-pressure part of a saturated-steam turbine of nuclear power stations to the preheater or steam directly passing off to the low-pressure part contains a high amount of moisture. This is removed by a separating device in the overflow pipe working as an axial cyclon. To this end a twist generator with radially mounted guide vanes forces a twisting movement on the water-steam mixture whereby the water component is thrown towards the wall of the overflow pipe. Behind the twist generator the overflow pipe is provided with ring slots or annular gaps through which the centrifuged water gets into water collecting chambers concentrically surrounding the overflow pipe. The main water seperation results from the first annular gap through centrifugal effects. The rest is removed by steam suction through the other gaps. For steam suction purposes, i.e. in order to produce an underpressure, the collecting chambers of these gaps are connected with the overflow pipe behind the twist generators by means of a suction pipe. In order to also remove small water droplets without increasing the twist, an agglomerator is installed in the overflow pipe before the twist generator. It consists of baffle or guide plates within an elliptic intermediate piece in a bend of the overflow pipe. Therefore the flanks of the guide plates run parallel to the flow direction of the steam. (DG/PB) [de

  19. Laser assisted jet nozzle isotope separation

    International Nuclear Information System (INIS)

    1981-01-01

    A process for separating fluent particles having different masses comprises the steps of: driving a fluent mixture of such particles around a curved passage toward a septum oriented to divide the mixture thereby accelerating such particles to impart a centrifugal force thereto; inducing type selective heating of a selected particle type in said mixture prior to termination of such acceleration; receiving the fraction of the mixture flowing past an outer surface of said septum in a first output conduit; and receiving the fraction of the mixture flowing past an inner surface of said septum in a second output conduit. The description of the process for isotope separation refers also to the use of infrared laser radiation to produce isotopically selective excitation of the U-235 isotope in UF 6 . (author)

  20. Design and control of an ideal heat-integrated distillation column (ideal HIDiC) system separating a close-boiling ternary mixture

    International Nuclear Information System (INIS)

    Huang Kejin; Shan Lan; Zhu Qunxiong; Qian Jixin

    2007-01-01

    Despite the fact that a stand-alone ideal heat-integrated distillation column (ideal HIDiC) can be thermodynamically efficient and operationally stable, the application of an ideal HIDiC system to separate a close-boiling multi-component mixture is still a challenging problem because of the possibility of strong interactions within/between the ideal HIDiCs involved. In this work, employment of two ideal HIDiCs to separate a close-boiling ternary mixture is studied in terms of static and dynamic performance. It is found that the ideal HIDiC system can be a competitive alternative with a substantial energy saving and comparable dynamic performance in comparison with its conventional counterpart. The direct sequence appears to be superior to the indirect sequence due to the relatively small vapor flow rates to the compressors. Controlling the bottom composition of the first ideal HIDiC with the pressure elevation from the stripping section to the rectifying section helps to suppress the disturbances from the feed to the second ideal HIDiC. Special caution should, however, be taken when the latent heat of the distillates is to be recovered within/between the ideal HIDiCs involved, because a positive feedback mechanism may be formed and give rise to additional difficulties in process operation

  1. Isotope separation process

    International Nuclear Information System (INIS)

    Wexler, Sol; Young, C.E.

    1976-01-01

    Description is given of method for separating a specific isotope from a mixture of isotopes of an actinide element present as MF 6 , wherein M is the actinide element. It comprises: preparing a feed gas mixture of MF 6 in a propellant gas; passing the feed gas mixture under pressure through an expansion nozzle while heating the mixture to about 600 0 C; releasing the heated gas mixture from the nozzle into an exhaust chamber having a reduced pressure, whereby a gas jet of MF 6 molecules, MF 6 molecular clusters and propellant gas molecules is formed, the MF 6 molecules having a translational energy of about 3 eV; converting the MF 6 molecules to MF 6 ions by passing the jet through a cross jet of electron donor atoms so that an electron transfer takes place between the MF 6 - molecules and the electron donor atoms whereby the jet is now quasi-neutral, containing negative MF 6 - ions and positive donor ions; passing the quasi-neutral jet through a radiofrequency mass filter tuned to separate the MF 6 ions containing the specific isotope from the MF 6 - ions of the other isotopes and neutralizing and collecting the MF 6 molecules of the specific isotope [fr

  2. Conceptual design of distillation-based hybrid separation processes.

    Science.gov (United States)

    Skiborowski, Mirko; Harwardt, Andreas; Marquardt, Wolfgang

    2013-01-01

    Hybrid separation processes combine different separation principles and constitute a promising design option for the separation of complex mixtures. Particularly, the integration of distillation with other unit operations can significantly improve the separation of close-boiling or azeotropic mixtures. Although the design of single-unit operations is well understood and supported by computational methods, the optimal design of flowsheets of hybrid separation processes is still a challenging task. The large number of operational and design degrees of freedom requires a systematic and optimization-based design approach. To this end, a structured approach, the so-called process synthesis framework, is proposed. This article reviews available computational methods for the conceptual design of distillation-based hybrid processes for the separation of liquid mixtures. Open problems are identified that must be addressed to finally establish a structured process synthesis framework for such processes.

  3. High mass isotope separation arrangement

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1976-01-01

    An isotope separation arrangement for separating a preselected isotope from a mixture of chemically-identical but isotopically-different molecules by either photon-induced pure revibrational or vibronic selective excitation of the molecules containing the atoms of the isotope to be separated from a lower to a higher energy state, and a chemical reaction of the higher energy state molecules with a chemically-reactive agent to form a chemical compound containing primarily the atoms of the isotope to be separated in a physicochemical state different from the physicochemical state of the mixture of chemically-identical but isotopically-different molecules. The chemical compound containing the atoms of the isotope to be separated may be subsequently processed to obtain the isotope. The laser configuration used to generate the photon beam is fully described

  4. An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory

    Directory of Open Access Journals (Sweden)

    Gang Xu

    2014-05-01

    Full Text Available In this study, an improved CO2 separation and purification system is proposed based on in-depth analyses of cryogenic separation and distillation theory as well as the phase transition characteristics of gas mixtures containing CO2. Multi-stage compression, refrigeration, and separation are adopted to separate the majority of the CO2 from the gas mixture with relatively low energy penalty and high purity. Subsequently, the separated crude liquid CO2 is distilled under high pressure and near ambient temperature conditions so that low energy penalty purification is achieved. Simulation results indicate that the specific energy consumption for CO2 capture is only 0.425 MJ/kgCO2 with 99.9% CO2 purity for the product. Techno-economic analysis shows that the total plant investment is relatively low. Given its technical maturity and great potential in large-scale production, compared to conventional MEA and SelexolTM absorption methods, the cost of CO2 capture of the proposed system is reduced by 57.2% and 45.9%, respectively. The result of this study can serve as a novel approach to recovering CO2 from high CO2 concentration gas mixtures.

  5. Investigation of H2S separation from H2S/CH4 mixtures using functionalized and non-functionalized vertically aligned carbon nanotube membranes

    Science.gov (United States)

    Gilani, Neda; Towfighi, Jafar; Rashidi, Alimorad; Mohammadi, Toraj; Omidkhah, Mohammad Reza; Sadeghian, Ahmad

    2013-04-01

    Separation of H2S from binary mixtures of H2S/CH4 using vertically aligned carbon nanotube membranes fabricated in anodic aluminum oxide (AAO) template was studied experimentally. Carbon nanotubes (CNTs) were grown in five AAO templates with different pore diameters using chemical vapor deposition, and CNT/AAO membranes with tubular carbon nanotube structure and open caps were selected for separation of H2S. For this, two tubular CNT/AAO membranes were fabricated with the CNT inner diameters of 23 and 8 nm. It was found that permeability and selectivity of the membrane with inner diameter of 23 nm for CNT were independent of upstream feed pressure and H2S feed concentration unlike that of CNT having an inner diameter of 8 nm. Selectivity of these membranes for separation of H2S was obtained in the ranges of 1.36-1.58 and 2.11-2.86, for CNTs with internal diameters of 23 and 8 nm, respectively. In order to enhance the separation of H2S from H2S/CH4 mixtures, dodecylamine was used to functionalize the CNT/AAO membrane with higher selectivity. The results showed that for amido-functionalized membrane, both upstream feed pressure and H2S partial pressure in the feed significantly increased H2S permeability, and selectivity for H2S being in the range of 3.0-5.57 respectively.

  6. Enhancement of students’ creative thinking skills on mixture separation topic using project based student worksheet

    Science.gov (United States)

    Nurisalfah, R.; Fadiawati, N.; Jalmo, T.

    2018-05-01

    The aim of this study is to describe the effectiveness of project based student worksheet in improving students' creative thinking skills. The research method is using quasi experiment with the matching only pre-test post-test control group design. The population in this research is all students of class VII SMP N 2 Belitang Madang Raya with class VII1 as control class and class VII4 as experiment class. The sample of this research is obtaining by purposive sampling technique. The effectiveness of project based student worksheet is based on significant post-test differences between the control class and the experiment class as well as the effect size. The results show that the using of project based student worksheet is effective in improving students' creative thinking skills on mixture separation topic.

  7. Monte Carlo simulations of interacting particle mixtures in ratchet potentials

    International Nuclear Information System (INIS)

    Fendrik, A J; Romanelli, L

    2012-01-01

    There are different models of devices for achieving a separation of mixtures of particles by using the ratchet effect. On the other hand, it has been proposed that one could also control the separation by means of appropriate interactions. Through Monte Carlo simulations, we show that inclusion of simple interactions leads to a decrease of the ratchet effect and therefore also a separation of the mixtures.

  8. Generalized Analysis of a Distribution Separation Method

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2016-04-01

    Full Text Available Separating two probability distributions from a mixture model that is made up of the combinations of the two is essential to a wide range of applications. For example, in information retrieval (IR, there often exists a mixture distribution consisting of a relevance distribution that we need to estimate and an irrelevance distribution that we hope to get rid of. Recently, a distribution separation method (DSM was proposed to approximate the relevance distribution, by separating a seed irrelevance distribution from the mixture distribution. It was successfully applied to an IR task, namely pseudo-relevance feedback (PRF, where the query expansion model is often a mixture term distribution. Although initially developed in the context of IR, DSM is indeed a general mathematical formulation for probability distribution separation. Thus, it is important to further generalize its basic analysis and to explore its connections to other related methods. In this article, we first extend DSM’s theoretical analysis, which was originally based on the Pearson correlation coefficient, to entropy-related measures, including the KL-divergence (Kullback–Leibler divergence, the symmetrized KL-divergence and the JS-divergence (Jensen–Shannon divergence. Second, we investigate the distribution separation idea in a well-known method, namely the mixture model feedback (MMF approach. We prove that MMF also complies with the linear combination assumption, and then, DSM’s linear separation algorithm can largely simplify the EM algorithm in MMF. These theoretical analyses, as well as further empirical evaluation results demonstrate the advantages of our DSM approach.

  9. CENTRIFUGAL SEPARATORS

    Science.gov (United States)

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  10. Characterization of bioactive mixtures oligogalacturonidos

    International Nuclear Information System (INIS)

    Mederos Torres, Yuliem; Hormaza Montenegro, Josefa; Reynaldo Escobar, Ines; Montesino Sequi, Raquel

    2011-01-01

    Oligogalacturonides are pectic oligosaccharides composed of lineal chains of D-galacturonic acid, linked by α (1-4) glycosidic linkage. Oligogalacturonides' mixtures are obtained by enzymatic hydrolysis of pectins of diverse vegetal species. These oligosaccharides unchain a diverse biological activity in plants, which depends mainly on their polymerization degrees. The National Institute of Agricultural Science has a patent technology at national scale that lets to obtain a mixture of oligogalacturonides with different polymerization degree. In this work is presented the characterization of oligogalacturonides by spectrophotometric analysis attending to their uronic acids, reductor sugars, and neutral sugars content. Also the chromatographic profile of samples in study is obtained, using the derivatization with 2-aminobenzamide label and the separation by high pH anion exchange chromatography. It is achieved the separation of at least eight galacturonic acid oligomers with a variable degree of polymerization. On the other hand, the analysis by Fourier transform-infrared spectroscopy (FT-IR) showed that mixtures were composed by galacturonic acid salts. Results indicated that starting from two pectic acids with different characteristics, mixtures of oligogalacturonides of similar chemical composition could be obtained, but they differ in the proportion that they are presented

  11. Iterative reconstruction methods for Thermo-acoustic Tomography

    International Nuclear Information System (INIS)

    Marinesque, Sebastien

    2012-01-01

    We define, study and implement various iterative reconstruction methods for Thermo-acoustic Tomography (TAT): the Back and Forth Nudging (BFN), easy to implement and to use, a variational technique (VT) and the Back and Forth SEEK (BF-SEEK), more sophisticated, and a coupling method between Kalman filter (KF) and Time Reversal (TR). A unified formulation is explained for the sequential techniques aforementioned that defines a new class of inverse problem methods: the Back and Forth Filters (BFF). In addition to existence and uniqueness (particularly for backward solutions), we study many frameworks that ensure and characterize the convergence of the algorithms. Thus we give a general theoretical framework for which the BFN is a well-posed problem. Then, in application to TAT, existence and uniqueness of its solutions and geometrical convergence of the algorithm are proved, and an explicit convergence rate and a description of its numerical behaviour are given. Next, theoretical and numerical studies of more general and realistic framework are led, namely different objects, speeds (with or without trapping), various sensor configurations and samplings, attenuated equations or external sources. Then optimal control and best estimate tools are used to characterize the BFN convergence and converging feedbacks for BFF, under observability assumptions. Finally, we compare the most flexible and efficient current techniques (TR and an iterative variant) with our various BFF and the VT in several experiments. Thus, robust, with different possible complexities and flexible, the methods that we propose are very interesting reconstruction techniques, particularly in TAT and when observations are degraded. (author) [fr

  12. Separation of metal ions by anion exchange in mixtures of hydrochloric acid and hydrofluoric acid

    International Nuclear Information System (INIS)

    Faris, J.P.

    1978-12-01

    Distribution coefficients were determined for the adsorption of more than 40 elements on anion-exchange resins from mixtures of HCl (0.1 to 12M) and HF (0.1-8M). Two resins, Dowex 1 x 10, 200 to 400 mesh and Dowex 1 x 4, 100 to 200 mesh, were used. Distribution coefficients were also determined for the adsorption of many elements on both resins from 0.1 to 12M HCl and 0.1 to 12M HF. Anion exchange in the presence of HF was found useful for separating impurities from various materials for their subsequent determination, and specific procedures used in our spectrochemical laboratory for this purpose are outlined. The results of a literature search on the use of anion exchange in hydrofluoric acid and fluoride-containing media are presented in an extensive bibliography. 404 references, 9 tables

  13. Hydrate-based methane separation from coal mine methane gas mixture by bubbling using the scale-up equipment

    International Nuclear Information System (INIS)

    Cai, Jing; Xu, Chun-Gang; Xia, Zhi-Ming; Chen, Zhao-Yang; Li, Xiao-Sen

    2017-01-01

    Highlights: •Hydrate-based methane separation was achieved in the large scale using SHW-II. •Bubbling method was beneficial to reduce energy consumption. •The optimal conditions were determined. •The morphology and flow characteristic of hydrate formation were filmed. -- Abstract: In this work, the hydrate-based methane (CH 4 ) separation from coal mine methane (CMM) gas mixture was carried out by bubbling with a scale-up equipment (SHW-II). The influences of gas/liquid volume ratios (0.25 and 0.60), gas bubble sizes (diameter: 20, 50 and 100 μm) and gas flow rates (7.50, 16.13 and 21.50 mL/min/L) on gas consumption and CH 4 recovery were systematically investigated at 277.15 K and 1.50 MPa. The hydrate formation morphology was filmed by a camera and the hydrate structure was determined by powder X-ray diffraction (PXRD). Gas bubbles generated when gas mixture flowed into bulk solution through a bubble plate from the bottom of SHW-II. Initially, the gas hydrates formed at the bubble boundary and grew up as the shell around the bubble with the continuously rising of the gas bubble, and finally accumulated in the interface between the gaseous phase and solution. The experimental results showed that the THF/CH 4 /N 2 hydrate in SHW-II presented structure II (sII). The gas/liquid volume ratio, gas bubble size and gas flow rate had influences on gas consumption and CH 4 recovery. The increase of gas/liquid volume ratio resulted in the decrease of gas consumption and CH 4 recovery, while the increase of gas flow rate caused the decrease of gas consumption. Both the maximum gas consumption and CH 4 recovery were achieved at the gas bubble with diameter of 50 μm. The optimal operating condition for large-scale CH 4 separation via clatharate hydrate was comprehensively defined as the gas/liquid volume ratio of 0.25, the gas bubble diameter of 50 μm and the gas flow rate of 16.13 mL/min/L at 277.15 K and 1.50 MPa.

  14. Thermophysical properties of binary mixtures of {l_brace}ionic liquid 2-hydroxy ethylammonium acetate + (water, methanol, or ethanol){r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Victor H. [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain); Mattedi, Silvana [Chemical Engineering Department, Polytechnic School, Federal University of Bahia (UFBA), 40210-630 Salvador-BA (Brazil); Martin-Pastor, Manuel [Unidade de Resonancia Magnetica, RIAIDT, edif. CACTUS, University of Santiago de Compostela (USC), P.O. Box 15706, Santiago de Compostela (Spain); Aznar, Martin [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Iglesias, Miguel, E-mail: miguel.iglesias@usc.es [Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain)

    2011-07-15

    Research highlights: > This paper reports the density and speed of sound data of binary mixtures {l_brace}2-hydroxy ethylammonium acetate + (water, or methanol, or ethanol){r_brace} measured between the temperatures (298.15 and 313.15) K at atmospheric pressure. > The aggregation, dynamic behavior, and hydrogen-bond network were studied using thermo-acoustic, X-ray, and NMR techniques. > The Peng-Robinson equation of state, coupled with the Wong-Sandler mixing rule using the COSMO-SAC model predicted the density of the solutions with relative mean deviations below than 3.0%. - Abstract: In this work, density and speed of sound data of binary mixtures of an ionic liquid consisting of {l_brace}2-hydroxy ethylammonium acetate (2-HEAA) + (water, methanol, or ethanol){r_brace} have been measured throughout the entire concentration range, from the temperature of (288.15 to 323.15) K at atmospheric pressure. The excess molar volumes, variations of the isentropic compressibility, the apparent molar volume, isentropic apparent molar compressibility, and thermal expansion coefficient were calculated from the experimental data. The excess molar volumes were negative throughout the whole composition range. Compressibility data in combination with low angle X-ray scattering and NMR measurements proved that the presence of micelles formed due to ion pair interaction above a critical concentration of the ionic liquid in the mixtures. The Peng-Robinson equation of state coupled with the Wong-Sandler mixing rule and COSMO-SAC model was used to predict densities and the calculated deviations were lower than 3%, for binary mixtures in all composition range.

  15. Evaluating oil/water separators

    International Nuclear Information System (INIS)

    Murdoch, M.A.

    1993-01-01

    Four commercially available oil/water separators were tested at an oil refinery test facility. The separators were the Alfa-Laval OFPX 413 disk-stack centrifuge, the Conoco Vortoil hydrocyclone system, International Separation Technology's Intr-Septor 250, and a modified Flo Trend gravity separator. Each machine was tested against mixtures of salt water and crude oil, and mixtures of salt water and a water-in-oil emulsion. The impact on separator performance from simulated sea motion, and from the addition of emulsion breakers and debris to the influent, were also evaluated. The test equipment, instrumentation, analysis facilities, test plans, and procedures to conduct the tests are described, but test results are not reported. Recommendations for improved test procedures are included. The inability to accurately monitor flow rates was found to have the greatest negative impact on test performance and results. Aspects of the test program that worked well included the use of flexible and semi-rigid hoses for customizing the test setups, the use of modular and leased tanks, and the sea motion simulator swing table design. 3 refs., 2 tabs

  16. Mixture analysis by long-range J-resolved 2D NMR

    International Nuclear Information System (INIS)

    Ha, S.T.K.; Lee, R.W.K.; Wilkins, C.L.

    1987-01-01

    In most spectroscopic qualitative analyses chromatographic separations are done before identification. Unfortunately, this general approach has suffered from a number of shortcomings. Off-line chromatographic separation followed by spectroscopic analysis is time consuming and inefficient and on-line analysis suffers from mismatch of the material flow requirements between chromatographic columns and spectroscopic instruments. An alternative mixture identification procedure solely based upon use of edited 13 C NMR spectra and a 13 C NMR chemical shift data base is reported. This approach has been demonstrated in the analyses of several mixtures, including a mixture of amino acids and some isomers. In all cases, identifications of components of these mixtures are successful

  17. Zeolitic Imidazolate Framework-8 (ZIF-8) Membranes for Kr/Xe Separation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ting; Feng, Xuhui; Elsaidi, Sameh K.; Thallapally, Praveen K.; Carreon, Moises A.

    2017-01-30

    Herein, we demonstrate that a prototypical type of metal organic framework, zeolitic imidazolate framework-8 (ZIF-8), in membrane form, can effectively separate Kr/Xe gas mixtures at industrially relevant compositions. The best membranes separated Kr/Xe mixtures with average Kr permeances as high as 1.5 × 10-8 ± 0.2 mol/m2 s Pa and average separation selectivities of 14.2 ± 1.9 for molar feed compositions corresponding to Kr/Xe ratio encountered typically in air. Molecular sieving, competitive adsorption, and differences in diffusivities were identified as the prevailing separation mechanisms. These membranes potentially represent a less-energy-intensive alternative to cryogenic distillation, which is the benchmark technology used to separate this challenging gas mixture. To our best knowledge, this is the first example of any metal organic membrane composition displaying separation ability for Kr/Xe gas mixtures.

  18. High mass isotope separation process and arrangement

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1978-01-01

    An isotope separation arrangement for separating a preselected isotope from a mixture of chemically identical but isotopically different molecules by either photon-induced pure rovibrational or vibronic selective excitation of the molecules containing the atoms of the isotope to be separated from a lower to a higher energy state, and a chemical reaction of the higher energy state molecules with a chemically reactive agent to form a chemical compound containing primarily the atoms of isotope to be separated in a physicochemical state different from the physicochemical state of the mixture of chemically identical but isotopically different molecules. The chemical compound containing the atoms of the isotope to be separated may be subsequently processed to obtain the isotope

  19. Thermoacoustic imaging of prostate cancer: comparison to histology

    Science.gov (United States)

    Patch, S. K.; Griep, S. K.; Jacobsohn, K.; See, W. A.; Hull, D.

    2014-03-01

    Ex vivo imaging of fresh prostate specimens was performed to test the hypothesis that the thermoacoustic (TA) contrast mechanism generated with very high frequency electromagnetic (EM) irradiation is sensitive to prostate cancer. Ex vivo imaging was performed immediately after radical prostatectomy, performed as part of normal care. Irradiation pulsewidth was 700 ns and duty cycle was extremely low. Typical specific absorption rate (SAR) throughout the prostate was 70-90 kW/kg during pulsing, but time-averaged SAR was below 2 W/kg. TA pressure pulses generated by rapid heating due to EM energy deposition were detected using single element transducers. 15g/L glycine powder mixed into DI water served as acoustic couplant, which was chilled to prevent autolysis. Spatial encoding was performed by scanning in tomographic "step-and-shoot" mode, with 3 mm translation between slices and 1.8-degree rotation between tomographic views. Histology slides for 3 cases scanned with 2.25 MHz transducers were marked for comparison to TA reconstructions. These three cases showed little, moderate, and severe involvement in the histology levels surrounding the verumontanum. TA signal strength decreased with percent cancerous involvement. When VHF is used for tissue heating, the TA contrast mechanism is driven by ionic content and we observed suppressed TA signal from diseased prostate tissue in the peripheral zone. For the 45 regions of interest analyzed, a reconstruction value of 0.4 mV provides 100% sensitivity but only 29% specificity.

  20. Simulation of startup period of hydrogen isotope separation distillation column

    International Nuclear Information System (INIS)

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, Eh.P.

    2003-01-01

    Kinetic procedure for the mathematical simulation of start-up regime of rectification columns for molecular hydrogen isotope separation was developed. Nonstationary state (start-up period) of separating column for rectification of multi-component mixture was calculated. Full information on equilibrium and kinetic physicochemical properties of components in separating mixtures was used for the calculations. Profile of concentration of components by height of column in task moment of time was calculated by means of differential equilibriums of nonstationary mass transfer. Calculated results of nonstationary state of column by the 2 m height, 30 mm diameter during separation of the mixture: 5 % protium, 70 % deuterium, 25 % tritium were illustrated [ru

  1. Phase separation of acetonitrile-water mixtures and minimizing of ice crystallites from there in confinement of MCM-41.

    Science.gov (United States)

    Kittaka, Shigeharu; Kuranishi, Miki; Ishimaru, Shinji; Umahara, Osamu

    2007-03-07

    The effect of confinement of an acetonitrile-water mixture, whose correlation length was comparable to the pore size of the mesopores of MCM-41 (d=2.4-3.6 nm), on the phase changes was studied. Used techniques were low temperature differential scanning calorimetry and Fourier transform infrared spectroscopy, where the phase separation, lowering of the freezing and melting temperatures, and phase transitions of the acetonitrile were detected. The latter occurred in the mesopores at temperatures similar to that of the pure liquid, while the melting temperature of the water in the mesopores<3.1 nm decreased markedly at higher acetonitrile contents, suggesting a marked lowering of ice crystallite size.

  2. Study on separation of methanol-butyl methylether-1-chlorobutane system

    International Nuclear Information System (INIS)

    Zhang Weijiang; Cao Tianhong

    2006-01-01

    The separation of mixture plays an important role in chemical, petrochemical, medical biochemical industries and environmental protection engineering. Liquid mixture with azeotropic phenomenon cannot be separated by conventional distillation as well as extractive distillation. But the combination of extraction and distillation can be effective for them. This paper includes many experiments with the ternary mixture of methanol butyl methyl ether and 1-chlorobytane, which shows that the system is not ternary azeotrope and can be separated by the combination of extraction and rectification using water as extractive solvent. (authors)

  3. Separation of carbon nanotubes into chirally enriched fractions

    Science.gov (United States)

    Doorn, Stephen K [Los Alamos, NM; Niyogi, Sandip [Los Alamos, NM

    2012-04-10

    A mixture of single-walled carbon nanotubes ("SWNTs") is separated into fractions of enriched chirality by preparing an aqueous suspension of a mixture of SWNTs and a surfactant, injecting a portion of the suspension on a column of separation medium having a density gradient, and centrifuging the column. In some embodiments, salt is added prior to centrifugation. In other embodiments, the centrifugation is performed at a temperature below room temperature. Fractions separate as colored bands in the column. The diameter of the separated SWNTs decreases with increasing density along the gradient of the column. The colored bands can be withdrawn separately from the column.

  4. ELECTROCHEMICAL SEPARATION AND CONCENTRATION OF HYDROGEN SULFIDE FROM GAS MIXTURES

    Science.gov (United States)

    Winnick, Jack; Sather, Norman F.; Huang, Hann S.

    1984-10-30

    A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

  5. Microbubble Distillation for Ethanol-Water Separation

    Directory of Open Access Journals (Sweden)

    Atheer Al-yaqoobi

    2016-01-01

    Full Text Available In the current study, a novel approach for separating ethanol-water mixture by microbubble distillation technology was investigated. Traditional distillation processes require large amounts of energy to raise the liquid to its boiling point to effect removal of volatile components. The concept of microbubble distillation by comparison is to heat the gas phase rather than the liquid phase to achieve separation. The removal of ethanol from the thermally sensitive fermentation broths was taken as a case of study. Consequently the results were then compared with those which could be obtained under equilibrium conditions expected in an “ideal” distillation unit. Microbubble distillation has achieved vapour compositions higher than that which could be obtained under traditional equilibrium conditions. The separation was achieved at liquid temperature significantly less than the boiling point of the mixture. In addition, it was observed that the separation efficiency of the microbubble distillation could be increased by raising the injected air temperature, while the temperature of the liquid mixture increased only moderately. The separation efficiency of microbubble distillation was compared with that of pervaporation for the recovery of bioethanol from the thermally sensitive fermentation broths. The technology could be controlled to give high separation and energy efficiency. This could contribute to improving commercial viability of biofuel production and other coproducts of biorefinery processing.

  6. Separation of Azeotropic Mixture Acetone + Hexane by Using Polydimethylsiloxane Membrane.

    Czech Academy of Sciences Publication Activity Database

    Randová, A.; Bartovská, L.; Kačírková, Marie; Ledesma, Oscar Iván Hernández; Červenková Šťastná, Lucie; Izák, Pavel; Žitková, Andrea; Friess, K.

    2016-01-01

    Roč. 170, OCT 1 (2016), s. 256-263 ISSN 1383-5866 R&D Projects: GA MŠk(CZ) LD14094 Institutional support: RVO:67985858 Keywords : azeotropic mixture * PDMS membrane * pervaporation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.359, year: 2016

  7. Electrostatic separation for recycling conductors, semiconductors, and nonconductors from electronic waste.

    Science.gov (United States)

    Xue, Mianqiang; Yan, Guoqing; Li, Jia; Xu, Zhenming

    2012-10-02

    Electrostatic separation has been widely used to separate conductors and nonconductors for recycling e-waste. However, the components of e-waste are complex, which can be classified as conductors, semiconductors, and nonconductors according to their conducting properties. In this work, we made a novel attempt to recover the mixtures containing conductors (copper), semiconductors (extrinsic silicon), and nonconductors (woven glass reinforced resin) by electrostatic separation. The results of binary mixtures separation show that the separation of conductor and nonconductor, semiconductor and nonconductor need a higher voltage level while the separation of conductor and semiconductor needs a higher roll speed. Furthermore, the semiconductor separation efficiency is more sensitive to the high voltage level and the roll speed than the conductor separation efficiency. An integrated process was proposed for the multiple mixtures separation. The separation efficiency of conductors and semiconductors can reach 82.5% and 88%, respectively. This study contributes to the efficient recycling of valuable resources from e-waste.

  8. Experimental study of thermoacoustic effects on a single plate. Pt. 1. Temperature fields

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, M.; Herman, C. [Johns Hopkins Univ., Baltimore, MD (USA). Dept. of Mech. Eng.

    2000-03-01

    The thermal interaction between a heated solid plate and the acoustically driven working fluid was investigated by visualizing and quantifying the temperature fields in the neighbourhood of the solid plate. A combination of holographic interferometry and high-speed cinematography was applied in the measurements. A better knowledge of these temperature fields is essential to develop systematic design methodologies for heat exchangers in oscillatory flows. The difference between heat transfer in oscillatory flows with zero mean velocity and steady-state flows is demonstrated in the paper. Instead of heat transfer from a heated solid surface to the colder bulk fluid, the visualized temperature fields indicated that heat was transferred from the working fluid into the stack plate at the edge of the plate. In the experiments, the thermoacoustic effect was visualized through the temperature measurements. A novel evaluation procedure that accounts for the influence of the acoustic pressure variations on the refractive index was applied to accurately reconstruct the high-speed, two-dimensional oscillating temperature distributions. (orig.)

  9. A distillation tray with high efficiency and excellent operating flexibility for viscous mixture separation

    Directory of Open Access Journals (Sweden)

    Li Qunsheng

    2014-01-01

    Full Text Available The flow-guided sieve-valve tray(FGS-VTwith high efficiency was designed to overcome the shortcoming of low operating flexibility of the flow-guided sieve tray. Its dimensions and geometry, as well as structure characteristics, were presented. The hydrodynamics and mass transfer performance, including dry-plate pressure drop, wet plate-pressure drop, weeping, entrainment and tray efficiency, of two types of FGS-VTs (FGS-VTs with 14 and 8 valves, respectively and one flow-guided sieve tray were tested in an air-water-oxygen cold model experiment with a 0.6 m diameter plexiglass column. The results demonstrate that FGS-VT with 14 valves works better than FGS-VT with 8 valves, and in comparison with the flow-guided sieve tray, the flow-guided sieve-valve tray with 14 valves has higher tray efficiency, bigger operating flexibility, and lower wet-plate pressure drop (when all the valves are opened fully.Additionally, two typical applications to separate the mixture with high viscosity, solid, powder, easy-to-foam or easy self-polymerization components proved the unique advantages of FGS-VT.

  10. Synthesis and characterization of ZIF-69 membranes and separation for CO2/CO mixture

    KAUST Repository

    Liu, Yunyang

    2010-05-01

    Continuous and c-oriented ZIF-69 membranes were successfully synthesized on porous alpha-alumina substrates by an in situ solvothermal method. The membranes were characterized by XRD, SEM and single-gas permeation tests. The BET measurements on crystals taken from the same mother liquor that was used for membrane synthesis yield a Langmuir surface area of 1138 m(2)/g. The stability of the membrane towards heat and different solvents were studied. Single-gas permeation experiments through ZIF-69 membranes were carried out by a vacuum method at room temperature using H-2, CH4, CO, CO2 and SF6, respectively. The permeances were in the order of H-2 > CO2 > CH4 > CO > SF6. The separation of CO2/CO gas mixture was investigated by gas chromatograph (GC) and the permselectivity of CO2/CO was 3.5 +/- 0.1 with CO2 permeance of 3.6 +/- 0.3 x 10(-8) mol m(-2) s(-1) Pa-1 at room temperature. (C) 2010 Elsevier B.V. All rights reserved.

  11. Large-scale separation of amino acids by continuous displacement chromatography

    Energy Technology Data Exchange (ETDEWEB)

    DeCarli, J.P. II; Carta, G.; Byers, C.H.

    1989-10-01

    Continuous annular chromatography (CAC) is a developing technology that allows truly continuous chromatographic separations. Previous work has demonstrated the utility of this technology for the separation of various materials by isocratic elution on a bench scale. Novel applications and improved operation of the process were studied in this work, demonstrating that CAC is a versatile apparatus which is capable of separations at high throughput. Three specific separation systems were investigated. Pilot-scale separations at high loadings were performed using an industrial sugar mixture as an example of scale-up for isocratic separations. Bench-scale experiments of a low concentration metal ion mixture were performed to demonstrate stepwise elution, a chromatographic technique which decreases dilution and increases sorbent capacity. Finally, the separation of mixtures of amino acids by ion exchange was investigated to demonstrate the use of displacement development on the CAC. This technique, which perhaps has the most potential, when applied to the CAC allowed simultaneous separation and concentration of multicomponent mixtures on a continuous basis. Mathematical models were developed to describe the CAC performance and optimize the operating conditions. For all the systems investigated, the continuous separation performance of the CAC was found to be very nearly the same as the batchwise performance of conventional chromatography. The technology appears, thus, to be very promising for industrial applications.

  12. Separation of uranium(V I) from binary solution mixtures with thorium(IV), zirconium(IV) and cerium(III) by foaming

    International Nuclear Information System (INIS)

    Shakir, K.; Aziz, M.; Benyamin, K.

    1992-01-01

    Foam separation has been investigated for the removal of uranium(V I), thorium(IV), zirconium(IV) and cerium(III) from dilute aqueous solutions at pH values ranging from about I to about II. Sodium laurel sulphate (Na L S) and acetyl trimethyl ammonium bromide (CTAB), being a strong anionic and a strong cationic surfactants, were used as collectors. The results indicate that Na L S can efficiently remove thorium(IV), zirconium(IV) and cerium(III) but not uranium(V I). CTAB, on the other hand, can successfully float only uranium(V I) and zirconium(IV). These differences in flotation properties of the different cations could be used to establish methods for the separation of uranium(V I) from binary mixtures with thorium(IV), zirconium(IV) or cerium(III). The results are discussed in terms of the hydrolytic behaviour of the tested cations and properties of used collectors.2 fig., 1 tab

  13. Chromatographic separation of europium and gadolinum mixtures by ethylenediaminedisuccinic acid

    International Nuclear Information System (INIS)

    Kolleganov, M.Yu.; Nazarov, P.P.; Martynenko, L.I.; Mtrofanova, N.D.; Spitsyn, V.I.

    1985-01-01

    Comparative investigation of chromatographic separation of impurities of Eu and Gd micro- and macroquantities by means of ethylenediaminedisuccinic (EDDS) and ethylene-diaminetetraacetic (EDTA) acids is performed. It is shown that EDTA is a sufficiently effective agent for separation of this pair of elements. The values of EU and Gd separation coefficients obtained in experiments with RE microquantities are not realized at Eu-Gd, macroquantities separation which probably is connected with the influence of polymerization processes in the systems containing RE and EDDS complexes

  14. In vivo tumor detection with combined MR–Photoacoustic-Thermoacoustic imaging

    Directory of Open Access Journals (Sweden)

    Lin Huang

    2016-09-01

    Full Text Available Here, we report a new method using combined magnetic resonance (MR–Photoacoustic (PA–Thermoacoustic (TA imaging techniques, and demonstrate its unique ability for in vivo cancer detection using tumor-bearing mice. Circular scanning TA and PA imaging systems were used to recover the dielectric and optical property distributions of three colon carcinoma bearing mice While a 7.0-T magnetic resonance imaging (MRI unit with a mouse body volume coil was utilized for high resolution structural imaging of the same mice. Three plastic tubes filled with soybean sauce were used as fiducial markers for the co-registration of MR, PA and TA images. The resulting fused images provided both enhanced tumor margin and contrast relative to the surrounding normal tissues. In particular, some finger-like protrusions extending into the surrounding tissues were revealed in the MR/TA infused images. These results show that the tissue functional optical and dielectric properties provided by PA and TA images along with the anatomical structure by MRI in one picture make accurate tumor identification easier. This combined MR–PA–TA-imaging strategy has the potential to offer a clinically useful triple-modality tool for accurate cancer detection and for intraoperative surgical navigation.

  15. Gas storage and separation by electric field swing adsorption

    Science.gov (United States)

    Currier, Robert P; Obrey, Stephen J; Devlin, David J; Sansinena, Jose Maria

    2013-05-28

    Gases are stored, separated, and/or concentrated. An electric field is applied across a porous dielectric adsorbent material. A gas component from a gas mixture may be selectively separated inside the energized dielectric. Gas is stored in the energized dielectric for as long as the dielectric is energized. The energized dielectric selectively separates, or concentrates, a gas component of the gas mixture. When the potential is removed, gas from inside the dielectric is released.

  16. Passive control of thermoacoustic instabilities in swirl-stabilized combustion at elevated pressures

    Directory of Open Access Journals (Sweden)

    L Justin Williams

    2016-09-01

    Full Text Available In this study, a porous insert is placed at the dump plane of a swirl-stabilized lean premixed combustor to passively suppress thermoacoustic instabilities. The diffuser-shaped annular ring of porous inert material influences the turbulent flow field directly, including recirculation zones and vortical and/or shear layer structures to passively control the acoustic performance of the combustor. The porous inert material is made of silicon carbide–hafnium carbide coated, high-strength, high-temperature-resistant open-cell foam materials. In this study, the porous insert concept is investigated at above-ambient operating pressures to demonstrate its suitability for practical combustion applications. Experiments are conducted in quartz and metal combustors, without and with the porous insert while varying operating pressure, equivalence ratio, and reactant flow rate. Measurements show that the porous insert, and consequent changes in the combustor flow field, decrease the sound pressure levels at the frequency of combustion instability at all operating conditions investigated in this study. The porous insert also decreases the broadband combustion noise, i.e. the measured sound pressure levels over a wide frequency range.

  17. Limiting factors in the pro-oxidants production with the use of fatty acids mixture separated from soapstock

    Directory of Open Access Journals (Sweden)

    V. I. Korchagin

    2017-01-01

    Full Text Available The synthesis of prooxidants - carboxylates of variable valence metals (iron, copper and cobalt was carried with the use of a mixture of fatty acids with an acid number of 100-120 mg KOH / g, separated from the soapstock, which is a liquid waste of oil- and fatproduction. Carboxylates of variable valency metals were synthesized in a high-energy ultrasound field using a generator USG13-0.1 / 22. Mixed thermal and ultrasound effects contribute to an increase in the yield of metal carboxylates. The maximum yield of prooxidates was over 84% (by weight.When carrying out the synthesis of carboxylates of metals of variable valence, ion activity was revealed in the exchange reactions with sodium salts on the basis of a mixture of fatty acids in the following order: Co2+ >Cu2+ >Fe2+. The synthesis of carboxylates of variable valence metals is a multifactor system and depends on temperature regimes, metal activity, viscosity and structural characteristics of a fatty acids mixture. The formation of metal carboxylates was carried out in a water-alcohol medium at a high rate for the heterogeneous systems, which are the exchange reactions between strong alkali salts and carbon acids. It should be noted that an increase in the synthesis temperature above 60 ° C with simultaneous ultrasound exposure reduced the yield of products and influenced the quality composition of the carboxylates of metals of variable valency.We should also take into account that ultrasound impact allows to obtain a prooxidant of the required dispersity and it is extremely important in the production of multifunctional and targeted additives. The use of ultrasound fields of high intensity in the synthesis of carboxylates of metals of variable valence is preferable in a less viscous medium due to the better ultrasound spread

  18. Performance of Carbon Nanotube/Polysulfone (CNT/Psf Composite Membranes during Oil–Water Mixture Separation: Effect of CNT Dispersion Method

    Directory of Open Access Journals (Sweden)

    Michael Olawale Daramola

    2017-03-01

    Full Text Available Effect of the dispersion method employed during the synthesis of carbon nanotube (CNT/polysulfone-infused composite membranes on the quality and separation performance of the membranes during oil–water mixture separation is demonstrated. Carbon nanotube/polysulfone composite membranes containing 5% CNT and pure polysulfone membrane (with 0% CNT were synthesized using phase inversion. Three CNT dispersion methods referred to as Method 1 (M1, Method 2 (M2, and Method 3 (M3 were used to disperse the CNTs. Morphology and surface property of the synthesized membranes were checked with scanning electron microscopy (SEM and Fourier-transform infrared (FTIR spectroscopy, respectively. Separation performance of the membranes was evaluated by applying the membrane to the separation of oil–water emulsion using a cross-flow filtration setup. The functional groups obtained from the FTIR spectra for the membranes and the CNTs included carboxylic acid groups (O–H and carbonyl group (C=O which are responsible for the hydrophilic properties of the membranes. The contact angles for the membranes obtained from Method 1, Method 2, and Method 3 were 76.6° ± 5.0°, 77.9° ± 1.3°, and 77.3° ± 4.5°, respectively, and 88.1° ± 2.1° was obtained for the pure polysulfone membrane. The oil rejection (OR for the synthesized composite membranes from Method 1, Method 2, and Method 3 were 48.71%, 65.86%, and 99.88%, respectively, indicating that Method 3 resulted in membrane of the best quality and separation performance.

  19. Method for separating isotopes

    International Nuclear Information System (INIS)

    Schlenker, R.F.

    1978-01-01

    A vortex tube for separating isotopes is described. A gas mixture containing the isotopic molecules enters the vortex tube under pressure and is separated into a hot discharge flow stream and a cold discharge flow stream. The hot discharge is enriched in lighter isotopic molecules whereas the cold discharge flow stream is enriched in the heavier isotopic molecules. The vortex tube can be used in a single stage or multistage isotope separation apparatus

  20. The separation of benzene and cyclohexane by the batch extractive distillation

    International Nuclear Information System (INIS)

    Zhang Weijiang; Gui Xia

    2006-01-01

    The separation of the mixture is very important in environmental protection engineering and productive department. Azeotropic liquid mixture can not be separated by conventional distillation. But extractive distillation or combination of the two can be valid for them. In this paper, an experiment to separate benzene and Cyclohexane by batch extractive distillation was carried out with N,N-dimethylformide (DMF), dimethyl sulfoxide (DMSO) and their mixture as extractive solvent in this paper. The effect of operation parameter such as solvent flow rate and Reflux ratio on the separation was studied in the same operating condition. The results showed that the separation effect was improved with the increase of solvent flow rate and the Reflux ratio. All the three extractive solvent can separate benzene and cyclohexane to some extent, But the best was N,N- dimethylformide (DMF), the next was the mixture, and the last was dimethyl sulfoxide (DMSO). In the experiment the best operation condition was with N,N-dimethylformide(DMF) as extractive solvent, the solvent flow rate being 12.33ml/min, the Reflux ratio being 6. (authors)

  1. Influence of throttling of the heavy fraction on the uranium isotope separation in the separation nozzle

    International Nuclear Information System (INIS)

    Bley, P.; Ehrfeld, W.; Heiden, U.

    1978-04-01

    In a separation nozzle cascade for enrichment of U-235 the cut of the separation elements is adjusted by throttling the heavy fraction. This control process influences directly the flow properties in the nozzle and may noticeably change its separation characteristics. This paper deals with an experimental investigation of the throttling effect on the separation and control characteristics of the separation nozzle operated with a H 2 /UF 6 mixture. In consideration of the extremely small characteristic dimensions of commercial separation nozzle elements the influence of manufacturing tolerances on the characteristics of the throttled nozzle was analysed in detail. It appears, that the elementary effect of isotope separation increases by throttling of the heavy fraction up to 5% without changing the optimum operating conditions. This increase of the elementary effect is not only obtained for separation nozzles with zero tolerances but also for separation nozzles having finite tolerances of the skimmer position. Tolerances of the nozzle width, however, become increasingly detrimental, when the heavy fraction is throttled. Regarding the control characteristics of the separation nozzle it was found out, that the UF 6 -cut of the throttled nozzle reacts more sensitively to alterations of the operating pressures and less sensitively to alterations of the UF 6 -concentration of the process gas mixture. (orig.) [de

  2. Process Dissociation and Mixture Signal Detection Theory

    Science.gov (United States)

    DeCarlo, Lawrence T.

    2008-01-01

    The process dissociation procedure was developed in an attempt to separate different processes involved in memory tasks. The procedure naturally lends itself to a formulation within a class of mixture signal detection models. The dual process model is shown to be a special case. The mixture signal detection model is applied to data from a widely…

  3. Isotopic separation

    International Nuclear Information System (INIS)

    Castle, P.M.

    1979-01-01

    This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

  4. Perception of trigeminal mixtures.

    Science.gov (United States)

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Jida Xing

    2015-06-01

    Full Text Available In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared

  6. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

    Science.gov (United States)

    Xing, Jida; Chen, Jie

    2015-06-23

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

  7. Microfluidic Separation of Ethylene and Ethane Using Frustrated Lewis Pairs.

    Science.gov (United States)

    Voicu, Dan; Stephan, Douglas W; Kumacheva, Eugenia

    2015-12-21

    Separation of gaseous olefins and paraffins is one of the most important separation processes in the industry. Development of new cost-effective technologies aims at reducing the high energy consumption during the separation process. Here, we took advantage of the reaction of frustrated Lewis pairs (FLPs) with ethylene to achieve reactive extraction of ethylene from ethylene-ethane mixtures. The extraction was studied using a microfluidic platform, which enabled a rapid, high-throughput assessment of reaction conditions to optimize gas separation efficiency. A separation factor of 7.3 was achieved for ethylene from a 1:1 volume ratio mixture of ethylene and ethane, which corresponded to an extracted ethylene purity of 88 %. The results obtained in the microfluidic studies were validated using infrared spectroscopy. This work paves the way for further development of the FLPs and optimization of reaction conditions, thereby maximizing the separation efficiency of olefins from their mixtures with paraffins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Method for separating mono- and di-octylphenyl phosphoric acid esters

    International Nuclear Information System (INIS)

    Arnold, W.D. Jr.

    1977-01-01

    A method for separating mono-octylphenyl phosphoric acid ester and di-octylphenyl phosphoric acid ester from a mixture thereof comprises reacting the ester mixture with a source of lithium or sodium ions to form a mixture of the phosphate salts; contacting the salt mixture with an organic solvent which causes the dioctylphenyl phosphate salt to be dissolved in the organic solvent phase and the mono-octylphenyl phosphate salt to exist in a solid phase; separating the phases; recovering the phosphate salts from their respective phases; and acidifying the recovered salts to form the original phosphoric acid esters

  9. Fabrication of Hydrophobic Membrane for the Separation of n-Hexane/Water Mixture Using Novel Oleophilic Nanoparticle and Kevlar Fabric, as a Superior Support

    Directory of Open Access Journals (Sweden)

    Hanieh Karimnezhad

    2017-07-01

    Full Text Available The fabrication of functionalized membranes with hydrophobic/oleophilic surfaces for the elimination of n-hexane from water using para-aminobenzoate alumoxane, boehmite-epoxide and a novel nanoparticle, i.e., Stearate Alumoxane by a simple coating technique, is reported here. FTIR was used to characterize nanoparticles. SEM and contact angle measurement analyses were used to identify the nanocomposite membranes. The concentrations of oil in permeate and retentate were measured by UV/vis spectrophotometer. The morphology of Stearate alumoxane nanoparticles was investigated by means of SEM images. The composed film of nanoparticles on the Kevlar fabric was hydrophobic with water contact angle of ~ 145° and oleophilic with oil contact angle of ~ 0º. In addition, the membranes retained stable hydrophobicity and high separation efficiency even after employing for 6 times. Applying these properties, a setup was considered using the functionalized Kevlar fabric to separate oil through down to a collector and leave water drops. Our batch filtration system was exclusively gravity-driven. The achieved separation system can separate the oily water mixture (with the concentration of 20 % (v/v n-hexane in water, effectively with a separation efficiency of 84%.

  10. Relaxation phenomena in dense gas separation membranes

    NARCIS (Netherlands)

    Wessling, Matthias

    1993-01-01

    Solution-diffusion membranes are widely used for the separation of gaseous and liquid mixtures. The separation of air (O2/N2), landfill gas (CH4/CO2) and purge gas streams (NH3/H2) in the ammonia synthesis are examples for state-of-the-art membrane gas separation processes. For the separation of

  11. Quantitative separation of the influence of hydrogen bonding of ethanol/water mixture on the shape recovery behavior of polyurethane shape memory polymer

    International Nuclear Information System (INIS)

    Lu, Haibao; Leng, Jinsong; Min Huang, Wei; Fu, Y Q

    2014-01-01

    A thermally responsive polyurethane shape memory polymer (SMP) can be actuated in water through a hydrogen bonding interaction between water and the SMP. In this work, we present a comprehensive approach to quantify the hydrogen bonding on the shape recovery behavior of a polyurethane SMP. The stimuli response to the hydrogen bonding of the polyurethane SMP was investigated in ethanol/water mixtures by varying the water content. It was found that depending on the water content, the SMP features a critical hydrogen bonding strength associated with its shape recovery behavior. The Hildebrand solubility parameter theory was employed to quantitatively identify and separate the hydrogen bonding effect of the ethanol/water mixture on the shape recovery ratio and the time. Furthermore, a phenomenological model was developed to predict the glass transition temperature and the shape recovery time of a polyurethane SMP and was verified by the available experimental results. (paper)

  12. Differential systems of flux and concentrations of a mixture in the separation by a plant (1963); Systemes differente des flux et des concentrations d'un melange en separation par une usine etagee (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Bouligand, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-11-15

    The study of transient flux and concentrations of a mixture in the separation by a plant with different interdependent stages leads to an examination of the solutions of certain types of differential systems. These systems are obtained from the representative graph of the plant and have a structural form. By Olga TAUSSKY's theorem and the introduction of steerable distances, the solutions of these systems are chiefly examined in their asymptotic behaviour. The appendix shows that solutions of partial differential equations relative to plants made of cascades with a slight separation have analogous properties. (author) [French] La recherche des regimes transitoires des flux et des concentrations d'un melange en separation par une usine etagee de forme quelconque conduit a etudier les solutions de certains types de systemes differentiels. Ces systemes sont deduits du graphe representatif de l'usine, et apparaissent sous une forme structuree. A l'aide du theoreme d'Olga TAUSSKY et par l'introduction d'ecarts orientes, les solutions de ces systemes sont principalement examinees dans leur comportement asymptotique. Un appendice montre que les solutions des systemes d'equations aux derivees partielles des usines en cascades a tres faible separation admettent des proprietes analogues. (auteur)

  13. Boundaries of the Realizability Region of Membrane Separation Processes

    Science.gov (United States)

    Tsirlin, A. M.; Akhrenemkov, A. A.

    2018-01-01

    The region of realizability of membrane separation systems having a constant total membrane area has been determined for a definite output of a final product at a definite composition of a mixture flow. The law of change in the pressure in the mixture, corresponding to the minimum energy required for its separation, was concretized for media close in properties to ideal gases and solutions.

  14. Separation of trace uranium from plutonium for subsequent analysis

    International Nuclear Information System (INIS)

    Marsh, S.F.

    1980-08-01

    Trace uranium quantities are separated from plutonium metal and plutonium oxide for subsequent analysis. Samples are dissolved in hydrobromic acid or a hydrobromic acid-hydrofluoric acid mixture. The U(VI)-halide complex is separated from nonsorbed Pu(III) on an anion exchange column using sequential washes of 9M HBr, a 0.1M HI-12M HCl mixture and 0.1M HCl

  15. Effect of homopolymer in polymerization-induced microphase separation process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jongmin; Saba, Stacey A.; Hillmyer, Marc A.; Kang, Dong-Chang; Seo, Myungeun (IBS-Korea); (KAIST); (UMMN)

    2017-09-01

    We report on the phase separation behaviors of polymerization mixtures containing a polylactide macro-chain transfer agent (PLA-CTA), styrene, divinylbenzene, hydroxyl-terminated PLA (PLA-OH), and a molecular chain transfer agent which enable the ability to tune the pore size of a cross-linked polymer monolith in a facile manner. Cross-linked monoliths were produced from the mixtures via reversible addition-fragmentation chain transfer (RAFT) polymerization and converted into cross-linked porous polymers by selective removal of PLA while retaining the parent morphology. We demonstrate that pore sizes are tunable over a wide range of length scales from the meso- to macroporous regimes by adjusting the ratio of PLA-CTA to PLA-OH in the reaction mixture which causes the phase separation mechanism to change from polymerization-induced microphase separation to polymerization-induced phase separation. The possibility of increasing porosity and inducing simultaneous micro- and macrophase separation was also realized by adjustments in the molar mass of PLA which enabled the synthesis of hierarchically meso- and macroporous polymers.

  16. Characterization and risk assessment of seasonal and weather dynamics in organic pollutant mixtures from discharge of a separate sewer system.

    Science.gov (United States)

    Beckers, Liza-Marie; Busch, Wibke; Krauss, Martin; Schulze, Tobias; Brack, Werner

    2018-05-15

    Sites of wastewater discharge are hotspots for pollution of freshwaters with organic micropollutants and are often associated with adverse effects to aquatic organisms. The assessment, monitoring and managment of these hotspots is challenged by variations in the pollutant mixture composition due to season, weather conditions and random spills. In this study, we unraveled temporal exposure patterns in organic micropollutant mixtures from wastewater discharge and analyzed respective acute and sublethal risks for aquatic organisms. Samples were taken from two components of a separate sewer system i) a wastewater treatment plant (WWTP) and ii) a rain sewer of a medium size town as well as from the receiving river in different seasons. Rain sewer samples were separately collected for rain and dry - weather conditions. We analyzed 149 compounds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). By considering the pollution dynamics in the point sources, we reduced the complexity of pollutant mixtures by k-means clustering to a few emission groups representing temporal and weather-related pollution patterns. From these groups, we derived biological quality element (BQE) - specific risk patterns. In most cases, one main risk driving emission group and a few individual risk driving compounds were identified for each BQE. While acute risk for fish was quite low, algae were exposed to seasonally emitted herbicides (terbuthylazine, spiroxamine) and crustaceans to randomly spilled insecticides (diazinon, dimethoate). Sublethal risks for all BQE were strongly influenced by constantly emitted pollutants, above all, pharmaceuticals. Variability of risks in the river was mainly driven by water discharge of the river rather than by season or peak events. Overall, the studied WWTP represented the major pollution source with a specific emission of agricultural compounds. However, the investigated rain sewer showed to be a constant pollution source due to illicit connections

  17. Separation of cerium from other lanthanides by leaching with nitric acid rare earth(III) hydroxide-cerium(IV) oxide mixtures

    International Nuclear Information System (INIS)

    Mioduski, T.; Dong Anh Hao; Hoang Hong Luan

    1989-01-01

    The objective of the present work is a method for separating Ce from other Ln in the raw natural mixtures of rare earth hydroxides obtained from Vietnamese and Mongolian fluorocarbonate ores. The method, a simple acid digestion, should combine a maximum Ln(III) concentration of the effluent solution with a nitrate counter-ion environment and high selectivity vs. leaching yield parameters. Under optimum conditions Ce (and Th, if present) virtually does not pass into solution while the yield of leaching and the sum of REE oxides concentration in the after-leach solution reach the maximum values of 97% (mass) and 0.18 kg x dm -3 , respectively. (author) 9 refs.; 8 tabs

  18. Method of separating radioactive krypton gas

    International Nuclear Information System (INIS)

    Kimura, Shigeru; Awada, Yoshihisa.

    1975-01-01

    Object: To effectively and safely separate and recover Kr-85, which requires a long storage period for attenuating radioactivity, from a mixture gas consisting of Kr-85 and Xe by a liquefaction distillation method. Structure: A mixture gas consisting of Kr and Xe is subjected to heat exchange in a cooler with Freon gas from a plurality of distillation towers for its temperature reduction from normal temperature to a lower temperature, and then it is supplied to a distillation tower. The distillation tower is held at a pressure above 15 ata, preferably around 20 ata, and a condenser provided at the top of the distillation tower is furnished with Freon as cooling medium. The rare mixture gas is distilled by liquefaction within a distillation tower, and Kr-85 is obtained from a top duct while obtaining Xe from a bottom duct. Xe after separation by liquefaction is returned to a rare mixture gas supply inlet of a liquefaction distillation means for repeated refinement in the distillation tower. (Kamimura, M.)

  19. Phosphazene membranes for gas separations

    Science.gov (United States)

    Stewart, Frederick F.; Harrup, Mason K.; Orme, Christopher J.; Luther, Thomas A.

    2006-07-11

    A polyphosphazene having a glass transition temperature ("T.sub.g") of approximately -20.degree. C. or less. The polyphosphazene has at least one pendant group attached to a backbone of the polyphosphazene, wherein the pendant group has no halogen atoms. In addition, no aromatic groups are attached to an oxygen atom that is bound to a phosphorus atom of the backbone. The polyphosphazene may have a T.sub.g ranging from approximately -100.degree. C. to approximately -20.degree. C. The polyphosphazene may be selected from the group consisting of poly[bis-3-phenyl-1-propoxy)phosphazene], poly[bis-(2-phenyl-1-ethoxy)phosphazene], poly[bis-(dodecanoxypolyethoxy)-phosphazene], and poly[bis-(2-(2-(2-.omega.-undecylenyloxyethoxy)ethoxy)ethoxy)phosphazene]- . The polyphosphazene may be used in a separation membrane to selectively separate individual gases from a gas mixture, such as to separate polar gases from nonpolar gases in the gas mixture.

  20. Slantingly cross loading sample system enables simultaneous performance of separation and mixture to detect molecular interactions on thin-layer chromatography.

    Science.gov (United States)

    Shimizu-Yumoto, Hiroko; Hayashi, Nobuyuki; Ichimura, Kazuo; Nakayama, Masayoshi

    2012-07-06

    Anthocyanins are major flower pigments that can be affected by copigments, colorless compounds that can modify anthocyanin coloration to more intense and bluer. Thin-layer chromatography (TLC) is an available technique to separate and analyze anthocyanins and copigments. To easily and comprehensively detect copigments, we added function of mixture of compounds to TLC; by slantingly cross loading samples on TLC, compounds are symmetrically developed at various angle lines from the upper origin to individual R(f) values and cross each other in an orderly fashion, where mixture is simultaneously performed with separation. Occurrence of copigments can be detected as a coloration change on the developed line of anthocyanin. Pink sweet pea (Lathyrus odoratus L.) petals were analyzed by the cross-TLC and a more intense spot and a paler spot on the anthocyanin line were detected. As each spot overlapped with an ultraviolet absorbance line, each of these ultraviolet absorption compounds was purified and identified as kaempferol 3-rhamnoside and 2-cyanoethyl-isoxazolin-5-one, respectively. Whereas kaempferol 3-rhamnoside is a flavonoid and had a general copigment effect of more intense and bluer coloration change, 2-cyanoethyl-isoxazolin-5-one is a compound whose structure is outside of conventional categories of copigments and had a novel effect to change anthocyanin coloration paler while maintaining color tone. We determined that the search for copigments should be carried out without pre-existing prediction of structures and effects. We have shown that slantingly cross loading samples system on plate-type chromatography is an effective technique for such comprehensive analysis of molecular interaction. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  1. Low Mach number analysis of idealized thermoacoustic engines with numerical solution.

    Science.gov (United States)

    Hireche, Omar; Weisman, Catherine; Baltean-Carlès, Diana; Le Quéré, Patrick; Bauwens, Luc

    2010-12-01

    A model of an idealized thermoacoustic engine is formulated, coupling nonlinear flow and heat exchange in the heat exchangers and stack with a simple linear acoustic model of the resonator and load. Correct coupling results in an asymptotically consistent global model, in the small Mach number approximation. A well-resolved numerical solution is obtained for two-dimensional heat exchangers and stack. The model assumes that the heat exchangers and stack are shorter than the overall length by a factor of the order of a representative Mach number. The model is well-suited for simulation of the entire startup process, whereby as a result of some excitation, an initially specified temperature profile in the stack evolves toward a near-steady profile, eventually reaching stationary operation. A validation analysis is presented, together with results showing the early amplitude growth and approach of a stationary regime. Two types of initial excitation are used: Random noise and a small periodic wave. The set of assumptions made leads to a heat-exchanger section that acts as a source of volume but is transparent to pressure and to a local heat-exchanger model characterized by a dynamically incompressible flow to which a locally spatially uniform acoustic pressure fluctuation is superimposed.

  2. Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

    KAUST Repository

    Nouh, Mostafa A.; Arafa, Nadim M.; Abdel-Rahman, Ehab

    2014-01-01

    A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack's position, length and plate spacing are the three main parameters that have been investigated in this study. Stack's position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine's most powerful operating point.

  3. Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

    KAUST Repository

    Nouh, Mostafa A.

    2014-01-01

    A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack\\'s position, length and plate spacing are the three main parameters that have been investigated in this study. Stack\\'s position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine\\'s most powerful operating point.

  4. Microwave pumped high-efficient thermoacoustic tumor therapy with single wall carbon nanotubes.

    Science.gov (United States)

    Wen, Liewei; Ding, Wenzheng; Yang, Sihua; Xing, Da

    2016-01-01

    The ultra-short pulse microwave could excite to the strong thermoacoustic (TA) shock wave and deeply penetrate in the biological tissues. Based on this, we developed a novel deep-seated tumor therapy modality with mitochondria-targeting single wall carbon nanotubes (SWNTs) as microwave absorbing agents, which act efficiently to convert ultra-short microwave energy into TA shock wave and selectively destroy the targeted mitochondria, thereby inducing apoptosis in cancer cells. After the treatment of SWNTs (40 μg/mL) and ultra-short microwave (40 Hz, 1 min), 77.5% of cancer cells were killed and the vast majority were caused by apoptosis that initiates from mitochondrial damage. The orthotopic liver cancer mice were established as deep-seated tumor model to investigate the anti-tumor effect of mitochondria-targeting TA therapy. The results suggested that TA therapy could effectively inhibit the tumor growth without any observable side effects, while it was difficult to achieve with photothermal or photoacoustic therapy. These discoveries implied the potential application of TA therapy in deep-seated tumor models and should be further tested for development into a promising therapeutic modality for cancer treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. SEPARATION OF URANIUM AND PLUTONIUM OXIDES

    Science.gov (United States)

    Benedict, G.E.; Lyon, W.L.

    1961-12-01

    ABS>A method of separating a mixture of UO/sub 2/ and PuO/sub 2/ is given which comprises immersing the mixture in a fused NaCl-KCl bath, chlorinating with chlorine or phosgene, and preferentially electrolytically or chemically reducing the UO/sub 2/Cl/sub 2/ so produced to UO/sub 2/ and filtering it out. (AEC)

  6. An analytical study of photoacoustic and thermoacoustic generation efficiency towards contrast agent and film design optimization

    Directory of Open Access Journals (Sweden)

    Fei Gao

    2017-09-01

    Full Text Available Photoacoustic (PA and thermoacoustic (TA effects have been explored in many applications, such as bio-imaging, laser-induced ultrasound generator, and sensitive electromagnetic (EM wave film sensor. In this paper, we propose a compact analytical PA/TA generation model to incorporate EM, thermal and mechanical parameters, etc. From the derived analytical model, both intuitive predictions and quantitative simulations are performed. It shows that beyond the EM absorption improvement, there are many other physical parameters that deserve careful consideration when designing contrast agents or film composites, followed by simulation study. Lastly, several sets of experimental results are presented to prove the feasibility of the proposed analytical model. Overall, the proposed compact model could work as a clear guidance and predication for improved PA/TA contrast agents and film generator/sensor designs in the domain area.

  7. Monaural ICA of white noise mixtures is hard

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Petersen, Kaare Brandt

    2003-01-01

    Separation of monaural linear mixtures of `white' source signals is fundamentally ill-posed. In some situations it is not possible to find the mixing coefficients for the full `blind' problem. If the mixing coefficients are known, the structure of the source prior distribution determines the sour...... of white noise signals and give a set of `no go' cases.......Separation of monaural linear mixtures of `white' source signals is fundamentally ill-posed. In some situations it is not possible to find the mixing coefficients for the full `blind' problem. If the mixing coefficients are known, the structure of the source prior distribution determines the source...

  8. Separation of compounds differing in isotopic composition

    International Nuclear Information System (INIS)

    Sievers, R.E.; Brooks, J.J.

    1975-01-01

    Compounds differing in isotopic composition are separated by introducing a mixture of the compounds into a chromatographic column containing a lanthanide chelate as a stationary phase and eluting from the column a fraction that is at least enriched with one of the compounds of the mixture. (U.S.)

  9. Method for upgrading diene-containing hydrocarbon mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, L.E. Jr.; Holcomb, D.E.

    1984-05-22

    There is disclosed a method for upgrading of hydrocarbon mixtures, so as to reduce their content of gum precursors such as diolefins and pseudo-diolefins, and provide a resulting product mixture suitable for mild hydrogenation, for use as a motor fuel or as a feed stock to an extraction unit. The process comprises obtaining a hydrocarbon mixture containing about 60-90 wt. % of aromatic components, about 3-40 wt. % of dienes and pseudodienes, and monoolefins, and up to about 6 wt. % of relatively unreactive organic compounds, reacting this mixture with elemental sulfur in the approximate weight ratio of about 5-95 wt. % of the hydrocarbon mixture with about 95-5 wt. % of elemental sulfur, the reaction being carried out at a temperature in the range of 100/sup 0/-150/sup 0/ C. for about 10 minutes to 24 hours with good mixing, removing the unreacted materials by distillation and separating a sulfur-hydrocarbon reaction product to provide the upgraded hydrocarbon mixture.

  10. Separation of compounds differing in isotopic composition

    International Nuclear Information System (INIS)

    Sievers, R.E.; Brooks, J.J.

    1976-01-01

    Compounds differing in isotopic composition are separated by introducing a mixture of the compounds into a chromatographic column containing a lanthanide chelate as a stationary phase and eluting from the column a fraction which is at least enriched with one of the compounds of the mixture. 17 claims, no drawings

  11. Simplified simulation of multicomponent isotope separation by gas centrifuge

    International Nuclear Information System (INIS)

    Guo Zhixiong; Ying Chuntong

    1995-01-01

    The expressions of diffusion equation for multicomponent isotope separation by gas centrifuge are derived by utilizing the simplified diffusion transport vector. A method of radial averaging which was restricted to a binary mixture is extended to multicomponent isotope mixtures by using an iterative scheme. A numerical analysis of tetradic UF 6 or SF 6 gas isotope separation by centrifuge is discussed when a special model of velocity distribution is given. The dependence of mutual separation factor for the components on their molecular weights' difference is obtained. Some aspects of the given model of gas fluid are also discussed

  12. Separation based adsorption of ethanol-water mixture in azeotropic solution by single-walled carbon, boron-nitride and silicon-carbide nanotubes.

    Science.gov (United States)

    Taheri, Siavash; Lakmehsari, Muhammad Shadman; Soltanabadi, Azim

    2017-08-01

    The separation of the azeotropic ethanol-water mixture (95.57wt% ethanol) over a wide range of pressures (100-100000kPa) was studied on armchair SWCNTs, SWSiCNTs and SWBNNTs with different diameters at 351.30K using GCMC simulations. The GCMC results demonstrated that ethanol and water molecules form a monolayer single-file, chain together in the center of (6,6) SWCNT, while a spiral ring of ethanol and water is formed in the center of (8,8), (10,10) and (12,12) SWCNTs. It was found that in SWCNTs, the adsorption of ethanol reduces the function of pressure, while water adsorption increases its function. Water selectivity rises as a function of pressure. Also, in SWBNNTs, the adsorption of water increases as a function of pressure, while ethanol adsorption is almost constant. However, in the case of SWSiCNTs, ethanol and water adsorptions are very similar to those of SWBNNTs, whereas the adsorptivities of SWSiCNTs are more than those of SWBNNTs. Our findings regarding adsorption and slope of adsorption indicate that higher pressures are favorable for separating water and ethanol by SWCNTs, while SWBNNTs and SWSiCNTs are demonstrate higher ethanol adsorptivities in lower pressures. Also, MD simulations have been performed to study the microscopic structure and diffusion of binary mixtures of water and ethanol within SWCNTs, SWSiCNTs and SWBNNTs. The MD simulations imply that the oxygen atoms are highly well-organized around themselves. Also, the MD results illustrate a similar tendency for oxygen of water (OW) and oxygen of ethanol (OE) to the wall of the nanotubes in all the pressures. In addition, from the MD results, self-diffusion of water and ethanol in all nanotubes were calculated and discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. EFFICIENCY OF METAL SCRAP SEPARATION IN EDDY CURRENT SEPARATOR

    Directory of Open Access Journals (Sweden)

    Gordan Bedeković

    2008-11-01

    Full Text Available Eddy-current separation is most often method used for the recovery of non-ferrous metals (Al, Cu, Zn, Pb from solid wastes and also for separating non-ferrous metals from each other. The feed material comes to rotary drum and magnetic field by belt conveyer. The changing magnetic field induce eddy currents in conductive (metallic particles. Because interaction between this currents and the magnetic field electrodynamic forces will act on conductive particles. Therefore the trajectories of conductive particles will be different from the trajectories of the non-conductive ones. Separation is a result of the combined actions of several forces (electrodynamic, gravitational and frictional. The paper presents results of aluminium recovery from mixture of metallic particles in eddy current separator. Testing were conducted under field condition. Results shows that is possible achieve recovery of 99 % and concentrate quality of 89 % of aluminium (the paper is published in Croatian.

  14. CO2 capture by Condensed Rotational Separation

    NARCIS (Netherlands)

    Benthum, van R.J.; Kemenade, van H.P.; Brouwers, J.J.H.; Golombok, M.

    2010-01-01

    Condensed Rotational Separation (CRS) technology is a patented method to upgrade gas mixtures. A novel application is thecapture of CO2 from coal-combustion fired power stations: Condensed Contaminant Centrifugal Separation in Coal Combustion(C5sep). CRS involves partial condensation of a gas

  15. The selective conversion of glutamic acid in amino acid mixtures using glutamate decarboxylase--a means of separating amino acids for synthesizing biobased chemicals.

    Science.gov (United States)

    Teng, Yinglai; Scott, Elinor L; Sanders, Johan P M

    2014-01-01

    Amino acids (AAs) derived from hydrolysis of protein rest streams are interesting feedstocks for the chemical industry due to their functionality. However, separation of AAs is required before they can be used for further applications. Electrodialysis may be applied to separate AAs, but its efficiency is limited when separating AAs with similar isoelectric points. To aid the separation, specific conversion of an AA to a useful product with different charge behavior to the remaining compounds is desired. Here the separation of L-aspartic acid (Asp) and L-glutamic acid (Glu) was studied. L-Glutamate α-decarboxylase (GAD, Type I, EC 4.1.1.15) was applied to specifically convert Glu into γ-aminobutyric acid (GABA). GABA has a different charge behavior from Asp therefore allowing a potential separation by electrodialysis. Competitive inhibition and reduced operational stability caused by Asp could be eliminated by maintaining a sufficiently high concentration of Glu. Immobilization of GAD does not reduce the enzyme's initial activity. However, the operational stability was slightly reduced. An initial study on the reaction operating in a continuous mode was performed using a column reactor packed with immobilized GAD. As the reaction mixture was only passed once through the reactor, the conversion of Glu was lower than expected. To complete the conversion of Glu, the stream containing Asp and unreacted Glu might be recirculated back to the reactor after GABA has been removed. Overall, the reaction by GAD is specific to Glu and can be applied to aid the electrodialysis separation of Asp and Glu. © 2014 American Institute of Chemical Engineers.

  16. SEPARATION OF METAL SALTS BY ADSORPTION

    Science.gov (United States)

    Gruen, D.M.

    1959-01-20

    It has been found that certain metal salts, particularly the halides of iron, cobalt, nickel, and the actinide metals, arc readily absorbed on aluminum oxide, while certain other salts, particularly rare earth metal halides, are not so absorbed. Use is made of this discovery to separate uranium from the rare earths. The metal salts are first dissolved in a molten mixture of alkali metal nitrates, e.g., the eutectic mixture of lithium nitrate and potassium nitrate, and then the molten salt solution is contacted with alumina, either by slurrying or by passing the salt solution through an absorption tower. The process is particularly valuable for the separation of actinides from lanthanum-group rare earths.

  17. Feasibility of correlating separation of ternary mixtures of neutral analytes via thin layer chromatography with supercritical fluid chromatography in support of green flash separations.

    Science.gov (United States)

    Ashraf-Khorassani, M; Yan, Q; Akin, A; Riley, F; Aurigemma, C; Taylor, L T

    2015-10-30

    Method development for normal phase flash liquid chromatography traditionally employs preliminary screening using thin layer chromatography (TLC) with conventional solvents on bare silica. Extension to green flash chromatography via correlation of TLC migration results, with conventional polar/nonpolar liquid mixtures, and packed column supercritical fluid chromatography (SFC) retention times, via gradient elution on bare silica with a suite of carbon dioxide mobile phase modifiers, is reported. Feasibility of TLC/SFC correlation is individually described for eight ternary mixtures for a total of 24 neutral analytes. The experimental criteria for TLC/SFC correlation was assumed to be as follows: SFC/UV/MS retention (tR) increases among each of the three resolved mixture components; while, TLC migration (Rf) decreases among the same resolved mixture components. Successful correlation of TLC to SFC was observed for most of the polar organic solvents tested, with the best results observed via SFC on bare silica with methanol as the CO2 modifier and TLC on bare silica with a methanol/dichloromethane mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Underdetermined Blind Source Separation in Echoic Environments Using DESPRIT

    Directory of Open Access Journals (Sweden)

    Melia Thomas

    2007-01-01

    Full Text Available The DUET blind source separation algorithm can demix an arbitrary number of speech signals using anechoic mixtures of the signals. DUET however is limited in that it relies upon source signals which are mixed in an anechoic environment and which are sufficiently sparse such that it is assumed that only one source is active at a given time frequency point. The DUET-ESPRIT (DESPRIT blind source separation algorithm extends DUET to situations where sparsely echoic mixtures of an arbitrary number of sources overlap in time frequency. This paper outlines the development of the DESPRIT method and demonstrates its properties through various experiments conducted on synthetic and real world mixtures.

  19. Protein separations using enhanced-fluidity liquid chromatography.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2017-11-10

    Enhanced-fluidity liquid chromatography (EFLC) methods using methanol/H 2 O/CO 2 and hydrophilic interaction liquid chromatography (HILIC) were explored for the separation of proteins and peptides. EFLC is a separation mode that uses a mobile phase made of conventional solvents combined with liquid carbon dioxide (CO 2 ) in subcritical conditions. The addition of liquid CO 2 enhances diffusivity and decreases viscosity while maintaining mixture polarity, which typically results in reduced time of analysis. TFA additive and elevated temperature were leveraged as key factors in the separation of a 13-analyte intact protein mixture in under 5min. Under these conditions EFLC showed modest improvement in terms of peak asymmetry and analysis time over the competing ACN/H 2 O separation. Protein analytes detected by electrospray ionization - quadrupole time of flight, were shown to be unaffected by the addition of CO 2 in the mobile phase. Herein, the feasibility of separating hydrophilic proteins up to 80kDa (with transferrin) is demonstrated for CO 2 -containing mobile phases. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. ADSORPTION METHOD FOR SEPARATING METAL CATIONS

    Science.gov (United States)

    Khym, J.X.

    1959-03-10

    The chromatographic separation of fission product cations is discussed. By use of this method a mixture of metal cations containing Zr, Cb, Ce, Y, Ba, and Sr may be separated from one another. Mentioned as preferred exchange adsorbents are resins containing free sulfonic acid groups. Various eluants, such as tartaric acid, HCl, and citric acid, used at various acidities, are employed to effect the selective elution and separation of the various fission product cations.

  1. Application of fluidization to separate packaging waste plastics.

    Science.gov (United States)

    Carvalho, M Teresa; Ferreira, Célia; Portela, Antía; Santos, João Tiago

    2009-03-01

    The objective of the experimental work described in this paper is the study of the separation of PS (polystyrene) from PET (polyethylene terephthalate) and PVC (polyvinyl chloride) from drop-off points using a fluidized bed separator. This is a low-cost process commonly used in the hydro-classification of mineral ores. Firstly, experimental tests were carried out with artificial granulated samples with different grain sizes, types and sources of plastic ("separability tests"). The particle settling velocities were determined under different operating conditions. Then, based on the results, the laboratory tests continued with real mixtures of waste plastics ("separation tests") and the efficiency of the process was evaluated. From a PET-rich mixture, a concentrate of PS with a 75% grade in PS was produced while the underflow was quite clear from PS (grade less than 0.5% in PS).

  2. Manufacturing cycle for pure neon-helium mixture production

    International Nuclear Information System (INIS)

    Batrakov, B.P.; Kravchenko, V.A.

    1980-01-01

    The manufacturing cycle for pure neon-helium mixture production with JA-300 nitrogen air distributing device has been developed. Gas mixture containing 2-3% of neon-helium mixture (the rest is mainly nitrogen 96-97%) is selected out of the cover of the JA-300 column condensator and enters the deflegmator under the 2.3-2.5 atm. pressure. The diflegmator presents a heat exchange apparatus in which at 78 K liquid nitrogen the condensation of nitrogen from the mixture of gases entering from the JA-300 column takes place. The enriched gas mixture containing 65-70% of neon-helium mixture and 30-35% of nitrogen goes out from the deflegmator. This enriched neon-helium mixture enters the gasgoeder for impure (65-70%) neon-helium mixture. Full cleaning of-neon helium mixture of nitrogen is performed by means of an adsorber. As adsorbent an activated coal has been used. Adsorption occurs at the 78 K temperature of liquid nitrogen and pressure P=0.1 atm. As activated coal cooled down to nitrogen temperature adsorbs nitrogen better than neon and helium, the nitrogen from the mixture is completely adsorbed. Pure neon-helium mixture from the adsorber comes into a separate gasgolder. In one campaign the cycle allows obtaining 2 m 3 of the mixture. The mixture contains 0.14% of nitrogen, 0.01% of oxygen and 0.06% of hydrogen

  3. Being everything to anyone: Applicability of thermoacoustic technology in the commercial refrigeration market

    Science.gov (United States)

    Poese, Matthew E.; Smith, Robert W. M.; Garrett, Steven L.

    2005-09-01

    This talk will compare electrodynamically driven thermoacoustic refrigeration technology to some common implementations of low-lift vapor-compression technology. A rudimentary explanation of vapor-compression refrigeration will be presented along with some of the implementation problems faced by refrigeration engineers using compressor-based systems. These problems include oil management, compressor slugging, refrigerant leaks and the environmental impact of refrigerants. Recently, the method of evaluating this environmental impact has been codified to include the direct effects of the refrigerants on global warming as well as the so-called ``indirect'' warming impact of the carbon dioxide released during the generation (at the power plant) of the electrical power consumed by the refrigeration equipment. It is issues like these that generate commercial interest in an alternative refrigeration technology. However, the requirements of a candidate technology for adoption in a mature and risk-averse commercial refrigeration industry are as hard to divine as they are to meet. Also mentioned will be the state of other alternative refrigeration technologies like free-piston Stirling, thermoelectric and magnetocaloric as well as progress using vapor compression technology with alternative refrigerants like hydrocarbons and carbon dioxide.

  4. Method of gas separation

    International Nuclear Information System (INIS)

    Weltner, W.W.

    1980-01-01

    In order to separate a mixture of gases having widely different partial pressures at a given temperature, a chamber is employed. A batch of gas mixture is passed into the chamber. The walls of the chamber are cooled by a refrigerant which passes through coils in heat exchange relationship with the walls. By this means the temperature of the chamber is cooled to a temperature (and held at such temperature until equilibrium is reached) at which all the components of the gas mixture have changed state, at least one being solidified and at least one liquefied. The liquid constituents are removed first. Then the chamber is warmed to facilitate removal of the previously solidified constituents. In an example, the gas mixture comprises nitrogen, argon, krypton and xenon, and the walls of the chamber are cooled by liquid nitrogen, the argon and nitrogen being liquefied and the xenon and krypton being solidified. (author)

  5. Separation of gases

    International Nuclear Information System (INIS)

    Wang, C.G.

    1980-01-01

    A process for separating gaseous mixtures of molecules of different mass comprises the steps of: causing a rotational nozzle to eject a contiguous plurality of successive groups of molecules into an evacuated space, the groups mutually overlapping to form a continuous stream of the mixture in the form of an Archimedean spiral, allowing the molecules of each group of molecules to move in accordance with their thermal velocities for a predetermined period of time following ejection, thereby to allow each group of molecules to form a generally spherical configuration the outer portion of which will be enriched, in molecules of lighter mass, relative to the inner portion thereof, using a deflector means co-rotating with the rotating nozzle to deflect molecules, which have been allowed to move for the predetermined period of time in accordance with their thermal velocities, from at least one desired portion of the stream and using a stationary collector means to collect the deflected molecules. The process is described with reference to the separation of isotopes of uranium hexafluoride. (author)

  6. Centrifugal separator. [for production of enriched U

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, J; Fujita, S I

    1970-02-25

    In a centrifugal separator of the concurrent flow through type, a rotating member having an inner and outer cylinder with an air gap therebetween is supported within a frame. A mixture to be separated is supplied to the interior of the inner cylinder through a hollow shaft inserted coaxially within the rotatable portion of a driving apparatus, with one end of the rotatable portion attached to the common inlet end cap of the cylinders which are thereby rotated. There are provided holes at the upper end of the inner cylinder through which the mixture enters the air gap to undergo separation, with the thus separated lighter component entering a separate chamber at the lower end of the inner cylinder through holes provided therein to thereafter be discharged from the outlet end thereof, while the heavier component is discharged from the outlet end of the outer cylinder through holes provided therein. The separated gases then enter their respective chambers within the frame for final removal where they are isolated from each other by sealing means to prevent remixture. Efficiency is heightened and, since no other complicated means are necessary for dividing and removing the separated components, the structure of the present centrifuge can be simplified and reduced in size.

  7. Improved gas mixtures for gas-filled particle detectors

    Science.gov (United States)

    Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

    Improved binary and tertiary gas mixture for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below about 0.5 eV; whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

  8. Theory of the separation of a gaseous mixture by diffusion through a porous wall (1962); Theorie de la separation d'un melange gazeux par diffusion a travers une paroi poreuse (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Breton, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-06-15

    The present-day theories of separation by gaseous diffusion (Present and de BETHUNE, KYNCH, BOSANQUET) are all based on the same model in which the pores are cylindrical capillaries. In the theory presented here, we substitute for this model that of a disordered and isotropic bed of identical spheres, which describes more accurately most of the porous media. We take as our starting point DERIAGUINE and BAKANOV'S permeability theory, which expresses the flow of a simple gas in such a bed when the latter is of high porosity. We first generalise this theory in the case of medium and low porosities; then, we go on to a mixture of two gases, from which we deduce our separation theory. Finally we compare our results with those of Present and de BETHUNE. (author) [French] Les theories actuelles de la separation par diffusion gazeuse (PRESENT et de BETHUNE, KYNCH, BOSANQUET) reposent toutes sur le modele des pores capillaires cylindriques. Dans la theorie presentee ici, nous substituons a ce modele celui d'un empilement desordonne et isotropes de spheres identiques, qui decrit plus correctement la plupart des milieux poreux. Nous partons de la theorie de la permeabilite de DERIAGUINE et BAKANOV, qui exprime l'ecoulement d'un gaz simple dans un tel empilement dans le cas ou la porosite en est elevee. Nous generalisons d'abord cette theorie du cas des porosites moyennes ou faibles, puis, passant a un melange de deux gaz, nous en deduisons une theorie de la separation. Pour terminer, nous comparons nos resultats a ceux de PRESENT et de BETHUNE. (auteur)

  9. Numerical analysis of wet separation of particles by density differences

    Science.gov (United States)

    Markauskas, D.; Kruggel-Emden, H.

    2017-07-01

    Wet particle separation is widely used in mineral processing and plastic recycling to separate mixtures of particulate materials into further usable fractions due to density differences. This work presents efforts aiming to numerically analyze the wet separation of particles with different densities. In the current study the discrete element method (DEM) is used for the solid phase while the smoothed particle hydrodynamics (SPH) is used for modeling of the liquid phase. The two phases are coupled by the use of a volume averaging technique. In the current study, simulations of spherical particle separation were performed. In these simulations, a set of generated particles with two different densities is dropped into a rectangular container filled with liquid. The results of simulations with two different mixtures of particles demonstrated how separation depends on the densities of particles.

  10. Heavy-light fermion mixtures at unitarity

    Energy Technology Data Exchange (ETDEWEB)

    Gezerlis, Alexandros [Los Alamos National Laboratory; Carlson, Joseph [Los Alamos National Laboratory; Gandol, S [UNIV. ILL; Schmidt, E [ITALY

    2009-01-01

    We investigate fermion pairing in the unitary regime for a mass ratio corresponding to a {sup 6}Li-{sup 40}K mixture using quantum Monte Carlo methods. The ground-state energy and the average light- and heavy-particle excitation spectrum for the unpolarized superfluid state are nearly independent of the mass ratio. In the majority light system, the polarized superfluid is close to the energy of a phase separated mixture of nearly fully polarized normal and unpolarized superfluid. For a majority of heavy particles, we find an energy minimum for a normal state with a ratio of {approx}3:1 heavy to light particles. A slight increase in attraction to k{sub F}a{approx}2.5 yields a ground state energy of nearly zero for this ratio. A cold unpolarized system in a harmonic trap at unitarity should phase separate into three regions, with a shell of unpolarized superfluid in the middle.

  11. Separation techniques: Chromatography

    Science.gov (United States)

    Coskun, Ozlem

    2016-01-01

    Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

  12. Segregative phase separation in aqueous mixtures of polydisperse biopolymers

    NARCIS (Netherlands)

    Edelman, M.W.

    2003-01-01

    Keywords: biopolymer, gelatine, dextran, PEO, phase separation, polydispersity, molar mass distribution, SEC-MALLS, CSLM The temperature-composition phase diagram of aqueous solutions of gelatine and dextran, which show liquid/liquid phase segregation, were explored at temperatures above the

  13. Experimental study of combustion characteristics of isolated pockets of hydrogen-air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Manoubi, M.; LaFleche, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada); Liang, Z., E-mail: zhe.liang@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Radulescu, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada)

    2016-06-15

    This paper examines the dynamics of unconfined hydrogen-air flames and the criterion for flame propagation between neighbouring pockets of reactive gas separated by air using the soap bubble technique. The combustion events were visualized using high-speed schlieren or large-scale shadowgraph systems. It was revealed that for sufficiently lean hydrogen-air mixtures characterized by low flame speeds, buoyancy effects become important at small scales. The critical radius of hemispherical flame that will rise due to buoyancy is highly sensitive to the hydrogen concentration. The test results demonstrate that for transition of a flame between neighbouring pockets, the separation distance between the bubbles is mainly determined by the expansion ratio for near stoichiometric mixture, but it becomes much smaller for leaner mixtures because the flame kernel rises due to buoyant effects before the flame can reach the second bubble, thus the separation distance is no longer governed by the expansion ratio. (author)

  14. Integrated acoustic and magnetic separation in microfluidic channels

    DEFF Research Database (Denmark)

    Adams, Jonathan; Thevoz, Patrick; Bruus, Henrik

    2009-01-01

    With a growing number of cell-based biotechnological applications, there is a need for particle separation systems capable of multiparameter separations at high purity and throughput, beyond what is presently offered by traditional methods including fluorescence activated cell sorting and column......-based magnetic separation. Toward this aim, we report on the integration of microfluidic acoustic and magnetic separation in a monolithic device for multiparameter particle separation. Using our device, we demonstrate high-purity separation of a multicomponent particle mixture at a throughput of up to 10...

  15. Extraction of zirconium(IV) and separation of 95Zr-95Nb from acidic thiocyanate media by LIX 54 and its mixtures with TBP

    International Nuclear Information System (INIS)

    Mishra, P.K.; Chakravortty, V.; Dash, K.C.; Das, N.R.; Bhattacharyya, S.N.

    1990-01-01

    Appreciable extraction of 95 Zr- 95 Nb by LIX 54 from aqueous HCl alone is not observed in the concentration range from 0.1 to 2 M HCl. Presence of thiocyanate ions results in appreciable extraction of this pair from such acid medium. Synergism has been observed in the extraction of zirconium(IV) by mixtures of LIX 54 and TBP from thiocyanate media, whereas there has been no appreciable synergism in case of niobium(V) under identical conditions. Slope analyses indicate the species extracted by pure TBP to be disolvate whereas for extraction by the mixtures of LIX 54 and TBP it is found to be monosolvate with respect to TBP. The extraction of both the metal ions have been found to depend on the concentration of acid as well as that of thiocyanate ions. Extraction increases with increase in percentage of either of the extractants. Effective separation of these congeneric pairs has been achieved by suitable choice of above system. Extraction is independent of aq. zirconium concentration up to 0.01 M above which it decreases. (orig.)

  16. Molten salt battery having inorganic paper separator

    Science.gov (United States)

    Walker, Jr., Robert D.

    1977-01-01

    A high temperature secondary battery comprises an anode containing lithium, a cathode containing a chalcogen or chalcogenide, a molten salt electrolyte containing lithium ions, and a separator comprising a porous sheet comprising a homogenous mixture of 2-20 wt.% chrysotile asbestos fibers and the remainder inorganic material non-reactive with the battery components. The non-reactive material is present as fibers, powder, or a fiber-powder mixture.

  17. New Results on Single-Channel Speech Separation Using Sinusoidal Modeling

    DEFF Research Database (Denmark)

    Mowlaee, Pejman; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2011-01-01

    We present new results on single-channel speech separation and suggest a new separation approach to improve the speech quality of separated signals from an observed mix- ture. The key idea is to derive a mixture estimator based on sinusoidal parameters. The proposed estimator is aimed at finding...... mixture estimator used in binary masks and the Wiener filtering approach, it is observed that the proposed method achieves an acceptable perceptual speech quality with less cross- talk at different signal-to-signal ratios. Moreover, the method is independent of pitch estimates and reduces the computational...... complexity of the separation by replacing the short-time Fourier transform (STFT) feature vectors of high dimensionality with sinusoidal feature vectors. We report separation results for the proposed method and compare them with respect to other benchmark methods. The improvements made by applying...

  18. Component separation in harmonically trapped boson-fermion mixtures

    DEFF Research Database (Denmark)

    Nygaard, Nicolai; Mølmer, Klaus

    1999-01-01

    We present a numerical study of mixed boson-fermion systems at zero temperature in isotropic and anise tropic harmonic traps. We investigate the phenomenon of component separation as a function of the strength ut the interparticle interaction. While solving a Gross-Pitaevskii mean-field equation ...... for the boson distribution in the trap, we utilize two different methods to extract the density profile of the fermion component; a semiclassical Thomas-Fermi approximation and a quantum-mechanical Slater determinant Schrodinger equation....

  19. Centrifugal gas separator

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, M

    1970-03-27

    A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art.

  20. Simulation of ethanol extractive distillation with mixed glycols as separating agent

    Directory of Open Access Journals (Sweden)

    I. D. Gil

    2014-03-01

    Full Text Available Extractive distillation is an alternative for ethanol dehydration processes that has been shown to be more effective than azeotropic distillation and, in close proximity, to be very competitive against the process that uses adsorption with molecular sieves. Glycols have been shown to be the most effective solvents in extractive distillation, mainly ethylene glycol and glycerol. In this work, an extractive distillation column was simulated with the Aspen Plus software platform, using the RadFrac module for distillation columns, to investigate the effect on the separation of the ethylene glycol-glycerol mixture composition, the separating agent feed stages, the separating agent split stream feed, and the azeotropic feed temperature. The NRTL model was used to calculate the phase equilibrium of these strongly polar mixtures. A rigorous simulation of the extractive distillation column finally established was also performed, including a secondary recovery column for the mixture of solvents and a recycle loop, to simulate an industrially relevant situation. This simulation allowed establishing the complete parameters to dehydrate ethanol: the optimal stage for separating agent feed is stage 4; the most adequate composition for the glycols mixture is 60 mol% ethylene glycol and 40 mol% glycerol. Finally, energetically efficient operating conditions for each one of the columns were established through a preliminary pinch analysis.

  1. Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport.

    Science.gov (United States)

    Farjoo, Afrooz; Kuznicki, Steve M; Sadrzadeh, Mohtada

    2017-10-06

    Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene) was studied within the temperature and pressure ranges of 25-600 °C and 110-160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption-diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

  2. Development of a methodology for the separation of europium and samarium from a mixture of rare earth oxides by electroreduction/ precipitation

    International Nuclear Information System (INIS)

    Chepcanoff, Vera

    2006-01-01

    The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer industries, nuclear medicine, lasers, pigments, etc., moving, in the last decade , a market of US$ 2 billions per year. Due to their similar properties, the RE elements are very difficult to separate, requiring complex processes, what make the products very expensive. Elements like Eu and Sm, which contents in the minerals are low (0.05% and 2.0%, respectively, in monazite) are extremely expensive, but their field of application justifies the research for looking for other processes, more simple and/or more effective. Trivalent state is a characteristic of all RE, but some of them presents oxidation state +2, like Ce, Eu, Sm and Yb. In the case of Eu and Sm, the focus of the present work, the divalent state is achieved by electro-reduction in the potentials -0.65 and -1.55 (SCE), respectively. This makes possible the separation of these elements from the other rare earths and from each other. Thus, making use of this characteristic, a process for the individual separation of Eu and Sm in (NH 4 ) 2 SO 4 solution by electro-reduction/precipitation is proposed, where Sm is first separated from the solution as sulfate, and Eu, that remains in the solution, is precipitated after the decrease of temperature and potential applied. The process developed from a synthetic Eu and Sm solution was applied to a mixture of semi-heavy RE oxide, produced at IPEN-CNEN/SP, obtaining the separation of Sm. This product was analyzed by spectrophotometry, showing high purity. (author)

  3. System and process for efficient separation of biocrudes and water in a hydrothermal liquefaction system

    Science.gov (United States)

    Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.; Oyler, James R.; Rotness, Jr, Leslie J.; Schmidt, Andrew J.; Zacher, Alan H.

    2016-08-02

    A system and process are described for clean separation of biocrudes and water by-products from hydrothermal liquefaction (HTL) product mixtures of organic and biomass-containing feedstocks at elevated temperatures and pressures. Inorganic compound solids are removed prior to separation of biocrude and water by-product fractions to minimize formation of emulsions that impede separation. Separation may be performed at higher temperatures that reduce heat loss and need to cool product mixtures to ambient. The present invention thus achieves separation efficiencies not achieved in conventional HTL processing.

  4. Correspondence Between “Stable” Flame Macrostructure and Thermo-acoustic Instability in Premixed Swirl-Stabilized Turbulent Combustion

    KAUST Repository

    Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Habib, Mohamed A. M.; Ghoniem, Ahmed F.

    2014-01-01

    Copyright © 2015 by ASME. In this paper, we conduct an experimental investigation to study the link between the flame macroscale structure - or flame brush spatial distribution - and thermo-acoustic instabilities, in a premixed swirl-stabilized dump combustor. We operate the combustor with premixed methane-air in the range of equivalence ratio (Φ) from the lean blowout limit to Φ = 0. 75. First, we observe the different dynamic modes in this lean range as Φ is raised. We also document the effect of Φ on the flame macrostructure. Next, we examine the correspondence between dynamic mode transitions and changes in flame macrostructure. To do so, we modify the combustor length - by downstream truncation - without changing the underlying flow upstream. Thus, the resonant frequencies of the geometry are altered allowing for decoupling the heat release rate fluctuations and the acoustic feedback. Mean flame configurations in the modified combustor and for the same range of equivalence ratio are examined, following the same experimental protocol. It is found that not only the same sequence of flame macrostructures is observed in both combustors but also that the transitions occur at a similar set of equivalence ratio. In particular, the appearance of the flame in the outside recirculation zone (ORZ) in the long combustor - which occurs simultaneously with the onset of instability at the fundamental frequency - happens at similar Φ when compared to the short combustor, but without being in latter case accompanied by a transition to thermo-acoustic instability. Then, we interrogate the flow field by analyzing the streamlines, mean, and rms velocities for the nonreacting flow and the different flame types. Finally, we focus on the transition of the flame to the ORZ in the acoustically decoupled case. Our analysis of this transition shows that it occurs gradually with an intermittent appearance of a flame in the ORZ and an increasing probability with Φ. The spectral

  5. Correspondence Between “Stable” Flame Macrostructure and Thermo-acoustic Instability in Premixed Swirl-Stabilized Turbulent Combustion

    KAUST Repository

    Taamallah, Soufien

    2014-12-23

    Copyright © 2015 by ASME. In this paper, we conduct an experimental investigation to study the link between the flame macroscale structure - or flame brush spatial distribution - and thermo-acoustic instabilities, in a premixed swirl-stabilized dump combustor. We operate the combustor with premixed methane-air in the range of equivalence ratio (Φ) from the lean blowout limit to Φ = 0. 75. First, we observe the different dynamic modes in this lean range as Φ is raised. We also document the effect of Φ on the flame macrostructure. Next, we examine the correspondence between dynamic mode transitions and changes in flame macrostructure. To do so, we modify the combustor length - by downstream truncation - without changing the underlying flow upstream. Thus, the resonant frequencies of the geometry are altered allowing for decoupling the heat release rate fluctuations and the acoustic feedback. Mean flame configurations in the modified combustor and for the same range of equivalence ratio are examined, following the same experimental protocol. It is found that not only the same sequence of flame macrostructures is observed in both combustors but also that the transitions occur at a similar set of equivalence ratio. In particular, the appearance of the flame in the outside recirculation zone (ORZ) in the long combustor - which occurs simultaneously with the onset of instability at the fundamental frequency - happens at similar Φ when compared to the short combustor, but without being in latter case accompanied by a transition to thermo-acoustic instability. Then, we interrogate the flow field by analyzing the streamlines, mean, and rms velocities for the nonreacting flow and the different flame types. Finally, we focus on the transition of the flame to the ORZ in the acoustically decoupled case. Our analysis of this transition shows that it occurs gradually with an intermittent appearance of a flame in the ORZ and an increasing probability with Φ. The spectral

  6. Method for separating krypton isotopes

    International Nuclear Information System (INIS)

    Porter, J.T.

    1980-01-01

    Methods and apparatus for separating krypton isotopes utilizing low temperature selective infrared excitation of 85krypton difluoride in an isotopic compound mixture. Multiphoton ir excitation and uv excitation techniques are used, as well as cryogenic matrix isolation and inert buffer gas isolation techniques

  7. Segregation of granular binary mixtures by a ratchet mechanism.

    Science.gov (United States)

    Farkas, Zénó; Szalai, Ferenc; Wolf, Dietrich E; Vicsek, Tamás

    2002-02-01

    We report on a segregation scheme for granular binary mixtures, where the segregation is performed by a ratchet mechanism realized by a vertically shaken asymmetric sawtooth-shaped base in a quasi-two-dimensional box. We have studied this system by computer simulations and found that most binary mixtures can be segregated using an appropriately chosen ratchet, even when the particles in the two components have the same size and differ only in their normal restitution coefficient or friction coefficient. These results suggest that the components of otherwise nonsegregating granular mixtures may be separated using our method.

  8. Magnetic separation for soil decontamination

    International Nuclear Information System (INIS)

    Avens, L.R.; Worl, L.A.; deAguero, K.J.; Padilla, D.D.; Prenger, F.C.; Stewart, W.F.; Hill, D.D.; Tolt, T.L.

    1993-01-01

    High gradient magnetic separation (HGMS) is a physical separation process that is used to extract magnetic particles from mixtures. The technology is used on a large scale in the kaolin clay industry to whiten or brighten kaolin clay and increase its value. Because all uranium and plutonium compounds are slightly magnetic, HGMS can be used to separate these contaminants from non-magnetic soils. A Cooperative Research and Development Agreement (CRADA) was signed in 1992 between Los Alamos National Laboratory (LANL) and Lockheed Environmental Systems and Technologies Company (LESAT) to develop HGMS for soil decontamination. This paper reports progress and describes the HGMS technology

  9. Phase separation in coamorphous systems: in silico prediction and the experimental challenge of detection.

    Science.gov (United States)

    Pajula, Katja; Wittoek, Lieke; Lehto, Vesa-Pekka; Ketolainen, Jarkko; Korhonen, Ossi

    2014-07-07

    Combinatorial chemistry has enabled the production of very potent drugs that might otherwise suffer from poor solubility and low oral bioavailability. One approach to increase solubility is to make the drug amorphous, which leads to problems associated with drug stability. To improve stability, one option is to molecularly disperse the drug in a matrix. However, the primary reason for the failed stabilization with this approach is phase separation, which has been carefully studied in polymeric systems. Nevertheless, the amorphous-amorphous phase separation in coamorphous small molecule mixtures has not yet been reported. The goal of the present study was to experimentally detect the amorphous-amorphous phase separation between two small molecules. A modified in silico method for predicting miscibility by the Flory-Huggins interaction parameter is presented, where conformational variations of the studied molecules were taken into account. A series of drug-drug mixtures, with different mixture ratios, were analyzed by conventional differential scanning calorimetry (DSC(conv)) to detect possible amorphous-amorphous phase separations. The phase separation of coamorphous drug-drug mixtures was also monitored by temperature modulated DSC (MDSC) and Fourier transform infrared (FT-IR) imaging at temperatures above Tg for prolonged time periods. Amorphous-amorphous phase separation was not detected with DSC(conv), probably due to the slow kinetics of phase separation. However, the melting of the separated and subsequently crystallized phases was detected by MDSC. Furthermore, FT-IR imaging was able to detect the separation of the two amorphous phases, which demonstrates the ability of this method to detect small molecule phase separations.

  10. Collective dynamics in dense fluid mixtures

    International Nuclear Information System (INIS)

    Sinha, S.

    1992-01-01

    This thesis deals with the short wavelength collective dynamics of dense binary fluid mixtures. The analysis shows that at the level of linearized generalized hydrodynamics, the longitudinal modes of the system separates essentially into two parts - one involves the coupling of partial density fluctuations of the two species and the other involves coupling of longitudinal momentum and temperature fluctuations. The authors have shown that the coupling of longitudinal momentum and temperature fluctuations leads to an adequate description of sound propagation in such systems. In particular, they show that structural disorder controls the trapping of sound waves in dense mixtures. The coupling of the partial density fluctuations of the two species leads to a simple description of the partial dynamic structure factors. The results are in agreement with the molecular dynamics simulations of soft sphere mixtures. The partial density fluctuations are the slowest decaying fluctuations on molecular length scales and it turns out that nonlinear coupling of these slow modes leads to important corrections to the long time behavior of the time correlation functions determining the shear viscosity in dense mixtures

  11. Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1987-01-01

    Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects....... The mixture caused mild to severe gastrointestinal distress in five subjects. When the carbohydrates were given separately, symptoms were absent. There was a significant correlation between the individual absorption capacities of fructose and of sorbitol. A mixture containing a similar amount of fructose......, but given as sucrose, and a similar amount of sorbitol was further given to four of the seven subjects showing malabsorption of the fructose-sorbitol mixture. Malabsorption now failed to appear, and symptoms were absent. These findings are of potential importance for the understanding of the physiologic...

  12. Methods and compositions for removing carbon dioxide from a gaseous mixture

    Science.gov (United States)

    Li, Jing; Wu, Haohan

    2014-06-24

    Provided is a method for adsorbing or separating carbon dioxide from a mixture of gases by passing the gas mixture through a porous three-dimensional polymeric coordination compound having a plurality of layers of two-dimensional arrays of repeating structural units, which results in a lower carbon dioxide content in the gas mixture. Thus, this invention provides useful compositions and methods for removal of greenhouse gases, in particular CO.sub.2, from industrial flue gases or from the atmosphere.

  13. Method and equipment of separation of gaseous and vaporous materials, particularly isotopes, with separation nozzles

    International Nuclear Information System (INIS)

    Becker, E.W.; Eisenbeiss, G.; Ehrfeld, W.

    1975-01-01

    The invention improves on the already known separation nozzle method by the two following steps: 1) The partial flows produced within the cascade with various shares of additional gas are introduced into the separating nozzle systems in such a manner that with regard to the additional gas, a molar fraction gradient is created which is in the opposite direction to the gradient created by the separation process. 2) The partial flows produced within the cascade with various compositions of the mixture of substances to be separated are introduced into the separating nozzle systems in such a manner that regarding the substances to be separated, a molar fraction gradient is created which is in the same direction as the molar fraction gradient formed by the separation process. Both measures can be separately applied or in combination with one another; flowsheets of the invented cascade circuits and separating nozzle systems are given. (GG/LH) [de

  14. Radial Chromatography for the Separation of Nitroaniline Isomers

    Science.gov (United States)

    Miller, Robert B.; Case, William S.

    2011-01-01

    Separation techniques are usually presented in the undergraduate organic laboratory to teach students how to purify and isolate compounds. Often the concept of liquid chromatography is introduced by having students create "silica gel columns" to separate components of a reaction mixture. Although useful, column chromatography can be a laborious…

  15. Simultaneous Design of Ionic Liquids and Azeotropic Separation for Systems Containing Water

    DEFF Research Database (Denmark)

    Roughton, Brock; Camarda, Kyle V.; Gani, Rafiqul

    Separation of azeotropic mixtures is a very common but challenging task, covering a wide range of industrial sectors and issues. For example, most down-stream separation problems following a synthesis step of pharmaceutical and/or biochemical processes, involve the separation of azeotropes. Also......, many separation tasks in the petrochemical and chemical industries involve separation of azeotropic mixtures. A common issue with the design and operation of these separation tasks is whether or not to use solvents? And, if solvents are to be used, what kind of solvent should be used and what would....... Since a large number of azeotropes encountered include water as one of the compounds, the use of ionic liquids in solvent-based separation of water in azeotropic systems has been investigated. Along with the design of the ionic liquid being used to entrain water, the extractive distillation process has...

  16. Estimating the number of sources in a noisy convolutive mixture using BIC

    DEFF Research Database (Denmark)

    Olsson, Rasmus Kongsgaard; Hansen, Lars Kai

    2004-01-01

    The number of source signals in a noisy convolutive mixture is determined based on the exact log-likelihoods of the candidate models. In (Olsson and Hansen, 2004), a novel probabilistic blind source separator was introduced that is based solely on the time-varying second-order statistics of the s......The number of source signals in a noisy convolutive mixture is determined based on the exact log-likelihoods of the candidate models. In (Olsson and Hansen, 2004), a novel probabilistic blind source separator was introduced that is based solely on the time-varying second-order statistics...

  17. Separation of racemic mixture by ultrafiltration of enantioselective micelles. 1 Effect of pH on separation and regeneration

    NARCIS (Netherlands)

    Overdevest, P.E.M.; Bruin, de T.J.M.; Riet, van 't K.; Keurentjes, J.T.F.; Padt, van der A.

    2001-01-01

    Many enantiomer separation systems are studied to meet the increasing demand for enantiopure compounds. One way to obtain pure enantiomers is to apply enantioselective micelles in ultrafiltration systems. We have studied the separation of phenylalanine (Phe) enantiomers by the ultrafiltration of

  18. Hydrogen separation membranes annual report for FY 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, U.; Dorris, S. E; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J. (Energy Systems)

    2011-03-14

    The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. The goal of this project is to develop dense hydrogen transport membranes (HTMs) that nongalvanically (i.e., without electrodes or external power supply) separate hydrogen from gas mixtures at commercially significant fluxes under industrially relevant operating conditions. These membranes will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. This report describes the results from the development and testing of HTM materials during FY 2010.

  19. Method and device for the separation of particles

    NARCIS (Netherlands)

    Rem, P.C.; Van Kooy, L.A.

    2004-01-01

    The invention relates to a method of in a liquid separating a mixture of particles that within chosen limits have different physical property values, wherein the particles to be separated are supplied via a feeder to a screen upon which a layer of facilitating particles is disposed, the size of the

  20. Facility to separate water and steam

    International Nuclear Information System (INIS)

    Loesel, G.

    1977-01-01

    The water/steam mixture from the pressure vessel e.g. of a BWR is separated by means of centrifugal separators untilizing the natural separation of steam. The steam is supplied to a steam drying vessel and the water to a water collecting tank. These vessels may be combined to a common vessel or connected through additional pipes. From the water collecting tank, arranged below the steam dryer, a feedwater pipe runs back to the pressure vessel. By construction out of individual components cleaning, decontamination, and operating control are essentially simplified. (RW) 891 RW [de

  1. Apparatus for diffusion separation

    International Nuclear Information System (INIS)

    Nierenberg, W.A.

    1976-01-01

    A diffuser separator apparatus is described which comprises a plurality of flow channels in a single stage. Each of said channels has an inlet port and an outlet port and a constant cross sectional area between said ports. At least a portion of the defining surface of each of said channels is a diffusion separation membrane, and each of said channels is a different cross sectional area. Means are provided for connecting said channels in series so that each successive channel of said series has a smaller cross sectional area than the previous channel of said series. Also provided are a source of gaseous mixture, individual means for flowing said gaseous mixture to the inlet port of each of said channels, gas receiving and analyzing means, individual means for flowing gas passing from each of said outlet ports and means for flowing gas passing through said membranes to said receiving and analyzing means, and individual means for connecting the outlet port of each channel with the inlet port of the channel having the next smaller cross sectional area

  2. Optimization of methanol crystallization for highly efficient separation of palmitic acid from palm fatty acid mixture using response surface methodology

    Directory of Open Access Journals (Sweden)

    A. A.W. Japir

    2018-01-01

    Full Text Available The objective of the current study was to develop parameters for the separation of palmitic acid (PA from a crude palm oil saturated fatty acid (SFAs mixture by using the methanol crystallization method. The conditions of methanol crystallization were optimized by the response surface methodology (RSM with the D-optimal design. The procedure of developing the solvent crystallization method was based on various different parameters. The fatty acid composition was carried out using a gas chromatography flame ionization detector (GC-FID as fatty acid methyl esters. The highest percentage of SFAs was more than 96% with the percentage yield of 87.5% under the optimal conditions of fatty acids-to-methanol ratio of 1: 20 (w/v, the crystallization temperature of -15 °C, and the crystallization time of 24 hours, respectively. The composition of separated SFAs in the solid fraction contains 96.7% of palmitic acid (C16:0 as a dominant component and 3.3% of stearic acid (C18:0. The results showed that utilizing methanol as a crystallization solvent is recommended because of its high efficiency, low cost, stability, availability, comparative ease of recovery and its ability to form needle-like crystals which have good filtering and washing characteristics.

  3. Optimization of methanol crystallization for highly efficient separation of palmitic acid from palm fatty acid mixture using response surface methodology

    International Nuclear Information System (INIS)

    Japir, A.A.W.; Salimon, J.; Derawi, D.; Yahaya, B.H.; Jamil, M.S.M.; Yusop, M.R.

    2017-01-01

    The objective of the current study was to develop parameters for the separation of palmitic acid (PA) from a crude palm oil saturated fatty acid (SFAs) mixture by using the methanol crystallization method. The conditions of methanol crystallization were optimized by the response surface methodology (RSM) with the D-optimal design. The procedure of developing the solvent crystallization method was based on various different parameters. The fatty acid composition was carried out using a gas chromatography flame ionization detector (GC-FID) as fatty acid methyl esters. The highest percentage of SFAs was more than 96% with the percentage yield of 87.5% under the optimal conditions of fatty acids-to-methanol ratio of 1: 20 (w/v), the crystallization temperature of -15 °C, and the crystallization time of 24 hours, respectively. The composition of separated SFAs in the solid fraction contains 96.7% of palmitic acid (C16:0) as a dominant component and 3.3% of stearic acid (C18:0). The results showed that utilizing methanol as a crystallization solvent is recommended because of its high efficiency, low cost, stability, availability, comparative ease of recovery and its ability to form needle-like crystals which have good filtering and washing characteristics. [es

  4. Separation of hydrogen isotopes via single column pressure swing adsorption

    International Nuclear Information System (INIS)

    Wong, Y.W.; Hill, F.B.

    1981-01-01

    Separation of hydrogen isotopes based on kinetic isotope effects was studied. The mixture separated was hydrogen containing a trace of tritium as HT and the hydride was vanadium monohydride. The separation was achieved using the single-column pressure swing process. Stage separation factors are larger and product cuts smaller than for a two-column pressure swing process operated in the same monohydride phase

  5. A general model for membrane-based separation processes

    DEFF Research Database (Denmark)

    Soni, Vipasha; Abildskov, Jens; Jonsson, Gunnar Eigil

    2009-01-01

    behaviour will play an important role. In this paper, modelling of membrane-based processes for separation of gas and liquid mixtures are considered. Two general models, one for membrane-based liquid separation processes (with phase change) and another for membrane-based gas separation are presented....... The separation processes covered are: membrane-based gas separation processes, pervaporation and various types of membrane distillation processes. The specific model for each type of membrane-based process is generated from the two general models by applying the specific system descriptions and the corresponding...

  6. Centrifugal gas separator

    International Nuclear Information System (INIS)

    Sakurai, Mitsuo.

    1970-01-01

    A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art. (K.J. Owens)

  7. Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport

    Directory of Open Access Journals (Sweden)

    Afrooz Farjoo

    2017-10-01

    Full Text Available Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene was studied within the temperature and pressure ranges of 25–600 °C and 110–160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption–diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

  8. Molecular separation method and apparatus

    International Nuclear Information System (INIS)

    Villa-Aleman, E.

    1996-01-01

    A method and apparatus are disclosed for separating a gaseous mixture of chemically identical but physically different molecules based on their polarities. The gaseous mixture of molecules is introduced in discrete quantities into the proximal end of a porous glass molecular sieve. The molecular sieve is exposed to microwaves to excite the molecules to a higher energy state from a lower energy state, those having a higher dipole moment being excited more than those with a lower energy state. The temperature of the sieve kept cold by a flow of liquid nitrogen through a cooling jacket so that the heat generated by the molecules colliding with the material is transferred away from the material. The molecules thus alternate between a higher energy state and a lower one, with the portion of molecules having the higher dipole moment favored over the others. The former portion can then be extracted separately from the distal end of the molecular sieve. 2 figs

  9. Linear Regression on Sparse Features for Single-Channel Speech Separation

    DEFF Research Database (Denmark)

    Schmidt, Mikkel N.; Olsson, Rasmus Kongsgaard

    2007-01-01

    In this work we address the problem of separating multiple speakers from a single microphone recording. We formulate a linear regression model for estimating each speaker based on features derived from the mixture. The employed feature representation is a sparse, non-negative encoding of the speech...... mixture in terms of pre-learned speaker-dependent dictionaries. Previous work has shown that this feature representation by itself provides some degree of separation. We show that the performance is significantly improved when regression analysis is performed on the sparse, non-negative features, both...

  10. Dynamic light scattering study on phase separation of a protein-water mixture: Application on cold cataract development in the ocular lens

    Science.gov (United States)

    Petta, V.; Pharmakakis, N.; Papatheodorou, G. N.; Yannopoulos, S. N.

    2008-06-01

    We present a detailed dynamic light scattering study of the phase separation in the ocular lens emerging during cold cataract development. Cold cataract is a phase separation effect that proceeds via spinodal decomposition of the lens cytoplasm with cooling. The intensity autocorrelation functions of the lens protein content are analyzed with the aid of two methods, providing information on the populations and dynamics of the scattering elements associated with cold cataract. It is found that the temperature dependence of many measurable parameters changes appreciably at the characteristic temperature ˜16±1°C which is associated with the onset of cold cataract. By extending the temperature range of this work to previously inaccessible regimes, i.e., well below the phase separation or coexistence curve at Tcc , we have been able to accurately determine the temperature dependence of the collective and self-diffusion coefficients of proteins near the spinodal. The analysis showed that the dynamics of proteins bears some resemblance to the dynamics of structural glasses, where the apparent activation energy for particle diffusion increases below Tcc , indicating a highly cooperative motion. Application of ideas developed for studying the critical dynamics of binary protein-solvent mixtures, as well as the use of a modified Arrhenius equation, enabled us to estimate the spinodal temperature Tsp of the lens nucleus. The applicability of dynamic light scattering as a noninvasive, early-diagnostic tool for ocular diseases is also demonstrated in light of the findings of the present paper.

  11. Radioactive krypton gas separation

    International Nuclear Information System (INIS)

    Martin, J.R.

    1976-01-01

    Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 16 Claims, 8 Drawing Figures

  12. Isotope separation in plasma by ion-cyclotron resonance method

    International Nuclear Information System (INIS)

    Dubinov, A.E.; Kornilova, I.Yu.; Selemir, V.D.

    2001-01-01

    Contemporary state of investigation on isotope separation in plasma using selective ion-cyclotron resonance (ICR) heating is considered. The main attention is paid to necessary conditions of heating selectivity, plasma creation methods in isotope ICR-separation facilities, selection of antenna systems for heating, and principles of more-heated component selection. Experimental results obtained at different isotope mixtures separation are presented [ru

  13. High atomic weight isotope separator

    International Nuclear Information System (INIS)

    Book, D.L.

    1978-01-01

    A continuously operating device is described which separates one isotopic species of a given element from a mixture. The given element is vaporized and formed into a neutral beam containing the isotopes desired to be separated. The plasma is accelerated through a laser beam which is formed by two separate lasers which operate in the continuous wave mode in which the beams are as nearly as possible in the same beam path. The two laser output beams excite and ionize the isotope of interest while leaving the remaining atoms unaffected. The ionized isotopes are then separated from the beam by an electrostatic deflection technique and the unaffected atoms continue on in their path and are directed to a recovery device

  14. Adsorption and separation of propane and propylene by porous hexacyanometallates

    International Nuclear Information System (INIS)

    Autie-Castro, G.; Autie, M.; Reguera, E.; Moreno-Tost, R.; Rodriguez-Castellon, E.; Jimenez-Lopez, A.; Santamaria-Gonzalez, J.

    2011-01-01

    The separation capability for mixtures of propane and propylene by porous frameworks representatives of transition metal hexacyanometallates was studied from adsorption data under equilibrium conditions at 273.15 K and from inverse gas chromatography profiles at different column temperatures. Samples of two porous solids were considered; Cd 3 [Co(CN) 6 ] 2 , which is representative of Prussian blue analogues (cubic structure) with a porous framework related to vacancies for building block, and Zn 3 [Co(CN) 6 ] 2 (rhombohedral phase) where the porous framework results from the tetrahedral coordination for the Zn atoms. The two materials were found to be able for the mixtures separation, with the highest separation ability for the rhombohedral phase under equilibrium conditions but, in dynamic conditions the cubic one shown a better separation, which was ascribed to a kinetic contribution related to a smaller windows size.

  15. Newly Developed Ceramic Membranes for Dehydration and Separation of Organic Mixtures by Pervaporation

    NARCIS (Netherlands)

    Gemert, van R.W.; Cuperus, F.P.

    1995-01-01

    Polymeric pervaporation membranes sometimes show great variety in performance when they are alternately used for different solvent mixtures. In addition, membrane stability in time is a problem in case of some solvents. Therefore, newly developed ceramic silica membranes with a 'dense' top layer

  16. Blind instantaneous noisy mixture separation with best interference-plus-noise rejection

    Czech Academy of Sciences Publication Activity Database

    Koldovský, Zbyněk; Tichavský, Petr

    2007-01-01

    Roč. 2007, Č. 4666 (2007), s. 730-737 ISSN 0302-9743. [Independent Component Analysis and Signal Separation. Londyn, 09.09.2007-12.09.2007] R&D Projects: GA MŠk 1M0572 Grant - others:GA ČR(CZ) GP102/07/P384 Program:GP Institutional research plan: CEZ:AV0Z10750506 Keywords : blind source separation * independent component analysis Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.402, year: 2005

  17. Separation of mixed waste plastics via magnetic levitation.

    Science.gov (United States)

    Zhao, Peng; Xie, Jun; Gu, Fu; Sharmin, Nusrat; Hall, Philip; Fu, Jianzhong

    2018-06-01

    Separation becomes a bottleneck of dealing with the enormous stream of waste plastics, as most of the extant methods can only handle binary mixtures. In this paper, a novel method that based on magnetic levitation was proposed for separating multiple mixed plastics. Six types of plastics, i.e., polypropylene (PP), acrylonitrile butadiene styrene (ABS), polyamide 6 (PA6), polycarbonate (PC), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE), were used to simulate the mixed waste plastics. The samples were mixed and immersed into paramagnetic medium that placed into a magnetic levitation configuration with two identical NdFeB magnets with like-poles facing each other, and Fourier transform infrared (FTIR) spectroscopy was employed to verify the separation outputs. Unlike any conventional separation methods such as froth flotation and hydrocyclone, this method is not limited by particle sizes, as mixtures of different size fractions reached their respective equilibrium positions in the initial tests. The two-stage separation tests demonstrated that the plastics can be completely separated with purities reached 100%. The method has the potential to be industrialised into an economically-viable and environmentally-friendly mass production procedure, since quantitative correlations are determined, and the paramagnetic medium can be reused indefinitely. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Separation of Olefin/Paraffin Mixtures with Carrier Facilitated Membrane Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, T.C.; Blanc, R.; Zeid, J.; Suwarlim, A.; Firat, B.; Wijmans, H.; Asaro, M. (SRI); Greene, M.(Lummus)

    2007-03-12

    This document describes the results of a DOE funded joint effort of Membrane Technology and Research Inc. (MTR), SRI International (SRI), and ABB Lummus (ABB) to develop facilitated transport membranes for olefin/paraffin separations. Currently, olefin/paraffin separation is done by distillation—an extremely energy-intensive process because of the low relative volatilities of olefins and paraffins. If facilitated transport membranes could be successfully commercialized, the potential energy savings achievable with this membrane technology are estimated to be 48 trillion Btu per year by the year 2020. We discovered in this work that silver salt-based facilitated transport membranes are not stable even in the presence of ideal olefin/paraffin mixtures. This decline in membrane performance appears to be caused by a previously unrecognized phenomenon that we have named olefin conditioning. As the name implies, this mechanism of performance degradation becomes operative once a membrane starts permeating olefins. This project is the first study to identify olefin conditioning as a significant factor impacting the performance of facilitated olefin transport membranes. To date, we have not identified an effective strategy to mitigate the impact of olefin conditioning. other than running at low temperatures or with low olefin feed pressures. In our opinion, this issue must be addressed before further development of facilitated olefin transport membranes can proceed. In addition to olefin conditioning, traditional carrier poisoning challenges must also be overcome. Light, hydrogen, hydrogen sulfide, and acetylene exposure adversely affect membrane performance through unwanted reaction with silver ions. Harsh poisoning tests with these species showed useful membrane lifetimes of only one week. These tests demonstrate a need to improve the stability of the olefin complexing agent to develop membranes with lifetimes satisfactory for commercial application. A successful effort

  19. URANIUM SEPARATION PROCESS

    Science.gov (United States)

    Lyon, W.L.

    1962-04-17

    A method of separating uranium oxides from PuO/sub 2/, ThO/sub 2/, and other actinide oxides is described. The oxide mixture is suspended in a fused salt melt and a chlorinating agent such as chlorine gas or phosgene is sparged through the suspension. Uranium oxides are selectively chlorinated and dissolve in the melt, which may then be filtered to remove the unchlorinated oxides of the other actinides. (AEC)

  20. Separation of tributyl phosphate from degraded solvents

    International Nuclear Information System (INIS)

    Kumar, S.V.; Nadkarni, M.N.; Ramanujam, A.; Venkatesan, M.; Gopalakrishnan, V.; Kazi, J.A.

    1977-01-01

    A solvent extraction method is described for the recovery of tributyl phosphate (TBP) from degraded process solvents. The method involves the separation of TBP and shell solT(SST) from 30% TBP/SSP mixture by thorium nitrate extraction leading to the formation of a heavy phase (third phase) which contains essentially TBP. The equilibrium experiments revealed that by utilizing thorium feeds of concentrations above 525 g/L in water at 1:1 ratio, a 30% TBP/SST mixture can be effectively separated into TBP and SST fractions with light SST phase having about 3% TBP. Using single stage mixer settler experiments, the feasibility of continuous separation of the three phases was assessed. Since there is a tendency for the degraded products of the diluent to seek the TBP phase, additional treatment steps would be necessary for their removal if the TBP is to be reused. Activated charcoal was investigated for this purpose. If purification of the TBP is not envisaged the volume of the organic waste generated in processing plants could be reduced by separating the diluent and TBP and only the TBP could be sent as concentrated waste. (author)

  1. Absolute molecular sieve separation of ethylene/ethane mixtures with silver zeolite A.

    Science.gov (United States)

    Aguado, Sonia; Bergeret, Gérard; Daniel, Cecile; Farrusseng, David

    2012-09-12

    Absolute ethylene/ethane separation is achieved by ethane exclusion on silver-exchanged zeolite A adsorbent. This molecular sieving type separation is attributed to the pore size of the adsorbent, which falls between ethylene and ethane kinetic diameters.

  2. Contributions to the analytical control of polyphenolic mixture

    Energy Technology Data Exchange (ETDEWEB)

    Barrera Pinero, R

    1961-07-01

    Separation and identification experiences of polyphenylic mixtures are described. the following technique are used: vacuum fractional distillation, vacuum sublimation and chromatography on acetylated paper. Also new coloured reactions of polyphenyls with aldehyde chlorides and their spectrophotometric application are studied. (Author) 17 refs.

  3. Contributions to the analytical control of polyphenylic mixture

    International Nuclear Information System (INIS)

    Barrera Pinero, R.

    1961-01-01

    Separation and identification experiences of polyphenylic mixtures are described. the following technique are used: vacuum fractional distillation, vacuum sublimation and chromatography on acetylated paper. Also new coloured reactions of polyphenyls with aldehyde chlorides and their spectrophotometric application are studied. (Author) 17 refs

  4. Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

    Science.gov (United States)

    Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

    2014-03-21

    Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

  5. Metal ion separations using reactive membranes

    International Nuclear Information System (INIS)

    Way, J.D.

    1993-01-01

    A membrane is a barrier between two phases. If one component of a mixture moves through the membrane faster than another mixture component, a separation can be accomplished. Membranes are used commercially for many applications including gas separations, water purification, particle filtration, and macromolecule separations (Abelson). There are two points to note concerning this definition. First, a membrane is defined based on its function, not the material used to make the membrane. Secondly, a membrane separation is a rate process. The separation is accomplished by a driving force, not by equilibrium between phases. Liquids that are immiscible with the feed and product streams can also be used as membrane materials. Different solutes will have different solubilities and diffusion coefficients in a liquid. The product of the diffusivity and the solubility is known as the permeability coefficient, which is proportional to the solute flux. Differences in permeability coefficient will produce a separation between solutes at constant driving force. Because the diffusion coefficients in liquids are typically orders of magnitude higher than in polymers, a larger flux can be obtained. Further enhancements can be accomplished by adding a nonvolatile complexation agent to the liquid membrane. One can then have either coupled or facilitated transport of metal ions through a liquid membrane. The author describes two implementations of this concept, one involving a liquid membrane supported on a microporous membrane, and the other an emulsion liquid membrane, where separation occurs to internal receiving phases. Applications and costing studies for this technology are reviewed, and a brief summary of some of the problems with liquid membranes is presented

  6. Membrane-Based Separation of Phenol/Water Mixtures Using Ionically and Covalently Cross-Linked Ethylene-Methacrylic Acid Copolymers

    Directory of Open Access Journals (Sweden)

    Alexander Mixa

    2008-01-01

    Full Text Available Membrane-based separation of phenol/water mixtures with concentrations of phenol between 3 wt% and 8 wt% in the feed has been performed with nonmodified as well as cross-linked ethylene-methacrylic acid (E-MAA copolymers with different amounts of methacrylic acid. As cross-linking agents, aluminium acetyl acetonate, which leads to ionically cross-linked membranes, and 2,3,5,6-tetramethyl-1,4-phenylene diamine and glycerine digycidether, leading to covalently cross-linked membranes, have been used. Generally, it was found that with increasing phenol content in the feed, the total flux is increasing whereas the enrichment factor is decreasing. Using nonmodified membranes with higher methacrylic acid monomer content in the polymer, lower fluxes and higher enrichment factors were observed. Investigation of different cross-linked membranes showed that with high phenol concentration in the feed, ionic cross-linking seems to be very promising. Furthermore, variation of feed temperature shows that ionically cross-linked membranes reached higher fluxes as well as higher enrichment factors at elevated temperatures. The temperature-dependent data were fitted based on an Arrhenius-type equation, and activation energies for the permeation of phenol and water through the membrane were calculated.

  7. Chemical Separation on Silver Nanorods Surface Monitored by TOF-SIMS

    Directory of Open Access Journals (Sweden)

    Ondrej Petruš

    2017-01-01

    Full Text Available The article introduces a possible chemical separation of a mixture of two compounds on the metal nanorods surface. A silver nanorods surface has been prepared by controlled electrochemical deposition in anodic alumina oxide (AAO template. Rhodamine 6G and 4-aminothiophenol have been directly applied to the sampling point on a silver nanorods surface in an aliquot mixture. The position of the resolved compounds was analysed by time-of-flight secondary ion mass spectrometry (TOF-SIMS which measured the fragments and the molecular ions of the two compounds separated on the silver nanorods surface. Rhodamine 6G has been preconcentrated as 1.5 mm radial from the sampling point while 4-aminothiophenol formed a continuous self-assembled monolayer on the silver nanorods surface with a maximum molecular ion intensity at a distance of 0.5 mm from the sampling point. The separation of the single chemical components from the two-component mixture over the examined silver nanostructured films could clearly be shown. A fast separation on the mentioned nanotextured films was observed (within 50 s. This procedure can be easily integrated into the micro/nanofluidic systems or chips and different detection systems can be applied.

  8. Superconductivity in Ba sub 1 sub - sub x K sub x BiO sub 3 : possible scenario of spatially separated Fermi-Bose mixture

    CERN Document Server

    Menushenkov, A P; Kuznetsov, A V; Kagan, M Y

    2001-01-01

    A new scenario for the metal-insulator phase transition and superconductivity in the perovskite-like bismuthates Ba sub 1 sub - sub x K sub x BiO sub 3 (BKBO) is proposed. It is shown that two types of charge carriers, the local pairs (real-space bosons) and the itinerant electrons, exist in the metallic compound BKBO (x >= 0.37). The real-space bosons are responsible for the charge transport in semiconducting BaBiO sub 3 and for superconductivity in the metallic BKBO. The appearance of the Fermi-liquid state as the percolation threshold is overcome (x >= 0.37) explains the observed metal-insulator phase transition. Because bosons and fermions occupy different types of the octahedral BiO sub 6 complexes, they are separated in real space, and therefore, the spatially separated Fermi-Bose mixture of a new type is likely to be realized in the bismuthates. The nature of superconductivity is consistently explained in the framework of this scenario. A new superconducting oxide Ba sub 1 sub - sub x La sub x PbO sub ...

  9. Adsorption and separation of propane and propylene by porous hexacyanometallates

    Energy Technology Data Exchange (ETDEWEB)

    Autie-Castro, G. [Instituto de Ciencia y Tecnologia de Materiales, Universidad de La Habana (Cuba); Autie, M. [Instituto de Ciencia y Tecnologia de Materiales, Universidad de La Habana (Cuba); Centro de Ingenieria y Proyectos (CIPRO), ISPJAE, La Habana (Cuba); Reguera, E., E-mail: ereguera@yahoo.com [Instituto de Ciencia y Tecnologia de Materiales, Universidad de La Habana (Cuba); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada del IPN, Unidad Legaria, Mexico DF (Mexico); Moreno-Tost, R.; Rodriguez-Castellon, E.; Jimenez-Lopez, A.; Santamaria-Gonzalez, J. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Facultad de Ciencias, Universidad de Malaga (Spain)

    2011-01-15

    The separation capability for mixtures of propane and propylene by porous frameworks representatives of transition metal hexacyanometallates was studied from adsorption data under equilibrium conditions at 273.15 K and from inverse gas chromatography profiles at different column temperatures. Samples of two porous solids were considered; Cd{sub 3}[Co(CN){sub 6}]{sub 2}, which is representative of Prussian blue analogues (cubic structure) with a porous framework related to vacancies for building block, and Zn{sub 3}[Co(CN){sub 6}]{sub 2} (rhombohedral phase) where the porous framework results from the tetrahedral coordination for the Zn atoms. The two materials were found to be able for the mixtures separation, with the highest separation ability for the rhombohedral phase under equilibrium conditions but, in dynamic conditions the cubic one shown a better separation, which was ascribed to a kinetic contribution related to a smaller windows size.

  10. Isotope separation apparatus

    International Nuclear Information System (INIS)

    Lyon, R.K.; Eisner, P.N.; Thomas, W.R.I.

    1983-01-01

    This application discloses a method for and an apparatus in which isotopes of an element in a compared are separated from each other while that compound, i.e., including a mixture of such isotopes, flows along a predetermined path. The apparatus includes a flow tube having a beginning and an end. The mixture of isotopes is introduced into the flow tube at a first introduction point between the beginning and the end thereof to flow the mixture toward the end thereof. A laser irradiates the flow tube dissociating compounds of a preselected one of said isotopes thereby converting the mixture in an isotopically selective manner. The dissociation products are removed from the tube at a first removal point between the first introduction point and the end. The dissociation product removed at the the first removal point are reconverted back into the comound thereby providing a first stage enriched compound. This first stage enriched compound is reintroduced into the flow tube at a second introduction point between the beginning thereof and the first introduction point. Further product is removed from the flow tube at a second removal point between the second introduction point and the first introduction point. The second introduction point is chosen so that the isotope composition of the first stage enriched compound is approximately the same as that of the compound in the flow tube

  11. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G. [East Tennessee Technology Park, Oak Ridge, TN (United States)

    1997-12-01

    The separative performance of the authors` ceramic membranes has been determined in the past using a permeance test system that measured flows of pure gases through a membrane at temperatures up to 275 C. From these data, the separation factor was determined for a particular gas pair from the ratio of the pure gas specific flows. An important project goal this year has been to build a Mixed Gas Separation System (MGSS) for measuring the separation efficiencies of membranes at higher temperatures and using mixed gases. The MGSS test system has been built, and initial operation has been achieved. The MGSS is capable of measuring the separation efficiency of membranes at temperatures up to 600 C and pressures up to 100 psi using a binary gas mixture such as hydrogen/methane. The mixed gas is fed into a tubular membrane at pressures up to 100 psi, and the membrane separates the feed gas mixture into a permeate stream and a raffinate stream. The test membrane is sealed in a stainless steel holder that is mounted in a split tube furnace to permit membrane separations to be evaluated at temperatures up to 600 C. The compositions of the three gas streams are measured by a gas chromatograph equipped with thermal conductivity detectors. The test system also measures the temperatures and pressures of all three gas streams as well as the flow rate of the feed stream. These data taken over a range of flows and pressures permit the separation efficiency to be determined as a function of the operating conditions. A mathematical model of the separation has been developed that permits the data to be reduced and the separation factor for the membrane to be determined.

  12. Chromatographic Separation of Vitamin E Enantiomers

    Directory of Open Access Journals (Sweden)

    Ju-Yen Fu

    2017-02-01

    Full Text Available Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.

  13. Aliphatic-aromatic separation using deep eutectic solvents as extracting agents

    NARCIS (Netherlands)

    Rodriguez Rodriguez, Nerea; Fernandez Requejo, Patricia; Kroon, Maaike

    2015-01-01

    The separation of aliphatic and aromatic compounds is a great challenge for chemical engineers. There is no efficient separation process for mixtures with compositions lower than 20 wt % in aromatics. In this work, the feasibility of two different deep eutectic solvents (DESs) as novel extracting

  14. Thermodiffusion in multicomponent n-alkane mixtures.

    Science.gov (United States)

    Galliero, Guillaume; Bataller, Henri; Bazile, Jean-Patrick; Diaz, Joseph; Croccolo, Fabrizio; Hoang, Hai; Vermorel, Romain; Artola, Pierre-Arnaud; Rousseau, Bernard; Vesovic, Velisa; Bou-Ali, M Mounir; Ortiz de Zárate, José M; Xu, Shenghua; Zhang, Ke; Montel, François; Verga, Antonio; Minster, Olivier

    2017-01-01

    Compositional grading within a mixture has a strong impact on the evaluation of the pre-exploitation distribution of hydrocarbons in underground layers and sediments. Thermodiffusion, which leads to a partial diffusive separation of species in a mixture due to the geothermal gradient, is thought to play an important role in determining the distribution of species in a reservoir. However, despite recent progress, thermodiffusion is still difficult to measure and model in multicomponent mixtures. In this work, we report on experimental investigations of the thermodiffusion of multicomponent n -alkane mixtures at pressure above 30 MPa. The experiments have been conducted in space onboard the Shi Jian 10 spacecraft so as to isolate the studied phenomena from convection. For the two exploitable cells, containing a ternary liquid mixture and a condensate gas, measurements have shown that the lightest and heaviest species had a tendency to migrate, relatively to the rest of the species, to the hot and cold region, respectively. These trends have been confirmed by molecular dynamics simulations. The measured condensate gas data have been used to quantify the influence of thermodiffusion on the initial fluid distribution of an idealised one dimension reservoir. The results obtained indicate that thermodiffusion tends to noticeably counteract the influence of gravitational segregation on the vertical distribution of species, which could result in an unstable fluid column. This confirms that, in oil and gas reservoirs, the availability of thermodiffusion data for multicomponent mixtures is crucial for a correct evaluation of the initial state fluid distribution.

  15. On the efficiency of a fluid-fluid centrifugal separation

    International Nuclear Information System (INIS)

    Apazidis, N.

    1984-05-01

    Efficiency of a separation process of two immiscible incompressible fluids of different densities occuring under the influence of a combined centrifugal and gravitational force field is investigated. The analysis is based on the set of equations for a rotating two-phase flow of a mixture as presented by Greenspan (1983). The geometry of the separation process is considered and the total flow of the separated phases evaluated. (author)

  16. Gas separation device based on electrical swing adsorption

    Science.gov (United States)

    Judkins, Roddie R.; Burchell, Timothy D.

    1999-10-26

    A method and apparatus for separating one constituent, especially carbon dioxide, from a fluid mixture, such as natural gas. The fluid mixture flows through an adsorbent member having an affinity for molecules of the one constituent, the molecules being adsorbed on the adsorbent member. A voltage is applied to the adsorbent member, the voltage imparting a current flow which causes the molecules of the one constituent to be desorbed from the adsorbent member.

  17. Particle separations by electrophoretic techniques

    International Nuclear Information System (INIS)

    Ballou, N.E.; Petersen, S.L.; Ducatte, G.R.; Remcho, V.T.

    1996-03-01

    A new method for particle separations based on capillary electrophoresis has been developed and characterized. It uniquely separates particles according to their chemical nature. Separations have been demonstrated with chemically modified latex particles and with inorganic oxide and silicate particles. Separations have been shown both experimentally and theoretically to be essentially independent of particle size in the range of about 0.2 μm to 10 μm. The method has been applied to separations of U0 2 particles from environmental particulate material. For this, an integrated method was developed for capillary electrophoretic separation, collection of separated fractions, and determinations of U0 2 and environmental particles in each fraction. Experimental runs with the integrated method on mixtures of UO 2 particles and environmental particulate material demonstrated enrichment factors of 20 for UO 2 particles in respect to environmental particles in the U0 2 containing fractions. This enrichment factor reduces the costs and time for processing particulate samples by the lexan process by a factor of about 20

  18. Influence of the composition of radionuclide mixtures on the maximum permissible concentration

    International Nuclear Information System (INIS)

    Schillinger, K.; Schuricht, V.

    1975-08-01

    By dividing radionuclides according to their formation mechanisms it is possible to assess the influence of separate partial mixtures on the maximum permissible concentration (MPC) of the total mixture without knowing exactly their contribution to the total activity. Calculations showed that the MPC of a total mixture of unsoluble radionuclides, which may occur in all fields of peaceful uses of nuclear energy, depends on the gastrointestinal tract as the critical organ and on the composition of the fission product mixture. The influence of fractionation on the MPC can be reglected in such a case, whereas in case of soluble radionuclides this is not possible

  19. Convolutive Blind Source Separation Methods

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Larsen, Jan; Kjems, Ulrik

    2008-01-01

    During the past decades, much attention has been given to the separation of mixed sources, in particular for the blind case where both the sources and the mixing process are unknown and only recordings of the mixtures are available. In several situations it is desirable to recover all sources from...... the recorded mixtures, or at least to segregate a particular source. Furthermore, it may be useful to identify the mixing process itself to reveal information about the physical mixing system. In some simple mixing models each recording consists of a sum of differently weighted source signals. However, in many...... real-world applications, such as in acoustics, the mixing process is more complex. In such systems, the mixtures are weighted and delayed, and each source contributes to the sum with multiple delays corresponding to the multiple paths by which an acoustic signal propagates to a microphone...

  20. Binary mixtures of condensates in generic confining potentials

    Energy Technology Data Exchange (ETDEWEB)

    Facchi, P [Dipartimento di Matematica and MECENAS, Universita di Bari, I-70125 Bari (Italy); Florio, G; Pascazio, S; Pepe, F V, E-mail: Francesco.Pepe@ba.infn.it [INFN, Sezione di Bari, I-70126 Bari (Italy)

    2011-12-16

    We study a binary mixture of Bose-Einstein condensates, confined in a generic potential, in the Thomas-Fermi approximation. We search for the zero-temperature ground state of the system, both in the case of fixed numbers of particles and fixed chemical potentials. For generic potentials, we analyze the transition from mixed to separated ground-state configurations as the inter-species interaction increases. We derive a simple formula that enables one to determine the location of the domain walls. Finally, we find criteria for the energetic stability of separated configurations, depending on the number and the position of the domain walls separating the two species. (paper)

  1. Binary mixtures of condensates in generic confining potentials

    Science.gov (United States)

    Facchi, P.; Florio, G.; Pascazio, S.; Pepe, F. V.

    2011-12-01

    We study a binary mixture of Bose-Einstein condensates, confined in a generic potential, in the Thomas-Fermi approximation. We search for the zero-temperature ground state of the system, both in the case of fixed numbers of particles and fixed chemical potentials. For generic potentials, we analyze the transition from mixed to separated ground-state configurations as the inter-species interaction increases. We derive a simple formula that enables one to determine the location of the domain walls. Finally, we find criteria for the energetic stability of separated configurations, depending on the number and the position of the domain walls separating the two species.

  2. Binary mixtures of condensates in generic confining potentials

    International Nuclear Information System (INIS)

    Facchi, P; Florio, G; Pascazio, S; Pepe, F V

    2011-01-01

    We study a binary mixture of Bose–Einstein condensates, confined in a generic potential, in the Thomas–Fermi approximation. We search for the zero-temperature ground state of the system, both in the case of fixed numbers of particles and fixed chemical potentials. For generic potentials, we analyze the transition from mixed to separated ground-state configurations as the inter-species interaction increases. We derive a simple formula that enables one to determine the location of the domain walls. Finally, we find criteria for the energetic stability of separated configurations, depending on the number and the position of the domain walls separating the two species. (paper)

  3. Studies on the adsorption behavior of CO2-CH4 mixtures using activated carbon

    Directory of Open Access Journals (Sweden)

    R. B. Rios

    2013-12-01

    Full Text Available Separation of CO2 from CO2-CH4 mixtures is an important issue in natural gas and biogas purification. The design of such separation processes depends on the knowledge of the behavior of multicomponent adsorption, particularly that of CO2-CH4 mixtures. In this study, we present a series of experimental binary equilibrium isotherms for CO2-CH4 mixtures on an activated carbon at 293 K and compare them with predicted values using the Ideal Adsorption Solution Theory (IAST and the Extended Langmuir (EL model. Even at concentrations of ca. 20% for all binary isotherms, CO2 already presents higher adsorbed amounts with respect to CH4. A maximum selectivity of around 8.7 was observed for a nearly equimolar mixture at 0.1 MPa. The IAST in conjunction with the Toth equation showed slightly better results than IAST using the Langmuir equation and both showed better results than the EL model.

  4. Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

    Science.gov (United States)

    Johnson, Brian J.

    2014-01-01

    Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

  5. Ionic liquid screening for ethylbenzene/styrene separation by extractive distillation

    NARCIS (Netherlands)

    Jongmans, M.T.G.; Schuur, B.; Haan, de A.B.

    2011-01-01

    The separation of ethylbenzene from styrene by distillation is very energy-intensive, because of the low relative volatility (1.3–1.4). Extractive distillation is a promising alternative to separate the close boiling mixture, in which the solvent selection is crucial for the process feasibility. In

  6. Optimization of a divided wall column for the separation of C4-C6 normal paraffin mixture using Box-Behnken design

    Directory of Open Access Journals (Sweden)

    Sangal Vikas K.

    2013-01-01

    Full Text Available In the present study, simulation of a divided wall column (DWC was carried out to study the product quality and energy efficiency as a function of reflux rate, liquid spilt and vapour split for the separation of C4-C6 normal paraffin ternary mixture. Rigorous simulation of the DWC was carried out using Multifrac model of ASPEN Plus software. Box-Behnken design (BBD was used for the optimization of parameters and to evaluate the effects and interaction of the process parameters such as reflux rate (r, liquid split (l and vapour split (v. It was found that the number of simulation runs reduced significantly for the optimization of DWC by BBD. Optimization by BBD under response surface methodology (RSM vividly underscores interactions between variables and their effects. The predictions agree well with the results of the rigorous simulation.

  7. Bubble and Dew Point Calculations in Multicomponent and Multireactive Mixtures

    OpenAIRE

    Bonilla-Petriciolet, A.; Acosta-Martínez, A.; Bravo-Sánchez, U. I.; Segovia-Hernández, J. G.

    2006-01-01

    Bubble and dew point calculations are useful in chemical engineering and play an important role in the study of separation equipments for non-reactive and reactive mixtures. To the best of the authors’s knowledge, few methods have been proposed for these calculations in systems with several chemical reactions. The objective of this paper is to introduce new conditions for performing bubble and dew point calculations in reactive mixtures. We have developed these conditions based on the a...

  8. Gaussian Process-Mixture Conditional Heteroscedasticity.

    Science.gov (United States)

    Platanios, Emmanouil A; Chatzis, Sotirios P

    2014-05-01

    Generalized autoregressive conditional heteroscedasticity (GARCH) models have long been considered as one of the most successful families of approaches for volatility modeling in financial return series. In this paper, we propose an alternative approach based on methodologies widely used in the field of statistical machine learning. Specifically, we propose a novel nonparametric Bayesian mixture of Gaussian process regression models, each component of which models the noise variance process that contaminates the observed data as a separate latent Gaussian process driven by the observed data. This way, we essentially obtain a Gaussian process-mixture conditional heteroscedasticity (GPMCH) model for volatility modeling in financial return series. We impose a nonparametric prior with power-law nature over the distribution of the model mixture components, namely the Pitman-Yor process prior, to allow for better capturing modeled data distributions with heavy tails and skewness. Finally, we provide a copula-based approach for obtaining a predictive posterior for the covariances over the asset returns modeled by means of a postulated GPMCH model. We evaluate the efficacy of our approach in a number of benchmark scenarios, and compare its performance to state-of-the-art methodologies.

  9. Source Separation of Heartbeat Sounds for Effective E-Auscultation

    Science.gov (United States)

    Geethu, R. S.; Krishnakumar, M.; Pramod, K. V.; George, Sudhish N.

    2016-03-01

    This paper proposes a cost effective solution for improving the effectiveness of e-auscultation. Auscultation is the most difficult skill for a doctor, since it can be acquired only through experience. The heart sound mixtures are captured by placing the four numbers of sensors at appropriate auscultation area in the body. These sound mixtures are separated to its relevant components by a statistical method independent component analysis. The separated heartbeat sounds can be further processed or can be stored for future reference. This idea can be used for making a low cost, easy to use portable instrument which will be beneficial to people living in remote areas and are unable to take the advantage of advanced diagnosis methods.

  10. Polymeric membranes containing silver salts for propylene/propane separation

    Directory of Open Access Journals (Sweden)

    L. D. Pollo

    2012-06-01

    Full Text Available The separation of olefin/paraffin mixtures is one of the most important processes of the chemical industry. This separation is typically carried out by distillation, which is an energy and capital intensive process. One promising alternative is the use of facilitated transport membranes, which contain specific carrier agents in the polymer matrix that interact reversibly with the double bond in the olefin molecule, promoting the simultaneous increase of its permeability and selectivity. In this study, polyurethane (PU membranes were prepared using two different silver salts (triflate and hexafluorantimonate. The membranes were structurally characterized and their performance for the separation of propylene/propane mixtures was evaluated. The results of the characterization analyses indicated that the triflate salt was the most efficient carrier agent. The membranes containing this salt showed the best performance, reaching an ideal selectivity of 10 and propylene permeability of 188 Barrer.

  11. Isotope separation in crossed-jet systems

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, R.J.; Anderson, J.B.

    1978-11-01

    The separation of isotopes in crossed-jet systems was investigated with Monte Carlo calculations of the separation effects for jets of Ne/Ar and /sup 235/UF/sub 6///sup 238/UF/sub 6/ mixtures entering a hydrogen stream. For the ideal condition of uniform stream velocities at zero temperature, the separation factor ..cap alpha.. was found to be 16.0 for Ne/Ar and 1.17 for /sup 235/UF/sub 6///sup 238/UF/sub 6/. For less ideal but more practical conditions, Monte Carlo calculations of the complete crossed-jet systems gave separation factors as high as 3.3 for Ne/Ar and ..cap alpha.. = 1.046 - 1.078 for /sup 235/UF/sub 6///sup 238/UF/sub 6/.

  12. Study on methane separation from steam reforming product gas with polyimide membrane

    International Nuclear Information System (INIS)

    Koiso, Hiroshi; Inagaki, Yoshiyuki; Aita, Hideki; Sekita, Kenji; Haga, Katsuhiro; Hino, Ryutaro.

    1997-10-01

    In the HTTR hydrogen production system by steam reforming of natural gas (main component: CH 4 ), CH 4 conversion rate is limited to approximately 65% due to high pressure and low temperature conditions (4.5 MPa, 800degC). The one of the measures to improve CH 4 conversion is recycling of residual CH 4 extracted from steam reforming product gas with a gas separator. Experimental and analytical studies on CH 4 separation from gas mixture composed of CH 4 , H 2 , CO 2 and CO were carried out to investigate gas separation characteristics of a polyimide membrane gas separator. Measured permeability of each gas in gas mixture was reduced from 1/3 to 1/14 of that obtained with a single gas (catalog value). The polyimide membrane could extracted CH 4 of approximately 80% from gas mixture, then, H 2 and CO 2 more than 98% were removed. It was confirmed that the polyimide membrane could be available to residual CH 4 recycling. The analytical results by a difference method gave good prospects of experimental results such as permeated flow rate, mol-fraction profiles and so on. Therefore, it can be said the analysis method was established. (author)

  13. Separation of tritium from gaseous and aqueous effluent systems

    International Nuclear Information System (INIS)

    Kobisk, E.H.

    1977-01-01

    Removal or reduction of tritium content in a wide variety of effluent streams has been extensively studied in the United States. This paper specifically reviews three processes involving tritium separation in the gaseous phase and the aqueous phase. Diffusion through a selective Pd-25Ag alloy membrane at temperatures up to 600 0 C and at pressures up to 700 kg/cm 2 has resulted in successful separation of hydrogen-deuterium mixtures with an associated separation factor of 1.65 (and gives a calculated separation factor for hydrogen-tritium mixtures of 2.0). Use of a single palladium bipolar membrane in an electrolysis system has been found to yield a hydrogen-deuterium separation factor of 4 and a hydrogen-tritium factor of 6 to 11 without the production of gaseous hydrogen. Finally, countercurrent catalytic exchange between tritium-containing hydrogen gas and water has yielded a separation factor of 6.3. The specific advantages of each of these systems will be discussed in terms of their potential applications. In all cases, further investigations are necessary to scale the systems to handle large quantities of feed material in a continuous mode and to minimize energy requirements. Such separative systems must necessarily be cascaded to yield gaseous or aqueous product streams suitable for recycling to the tritium producing systems, for storage or for discharge to the environment. (orig./HP) [de

  14. Separation and purification of xenon

    International Nuclear Information System (INIS)

    Schlea, C.S.

    1978-01-01

    Xenon is separated from a mixture of xenon and krypton by extractive distillation using carbon tetrafluoride as the partitioning agent. Krypton is flushed out of the distillation column with CF 4 in the gaseous overhead stream while purified xenon is recovered from the liquid bottoms. The distillation is conducted at about atmospheric pressure or at subatmospheric pressure

  15. Phase equilibria in chemical reactive fluid mixtures

    International Nuclear Information System (INIS)

    Maurer, Gerd

    2011-01-01

    Downstream processing is a major part of nearly all processes in the chemical industries. Most separation processes in the chemical (and related) industries for fluid mixtures are based on phase equilibrium phenomena. The majority of separation processes can be modelled assuming that chemical reactions are of no (or very minor) importance, i.e., assuming that the overall speciation remains unchanged during a separation process. However, there are also a large number of industrially important processes where the thermodynamic properties are influenced by chemical reactions. The phase equilibrium of chemical reactive mixtures has been a major research area of the author's group over nearly 40 years. In this contribution, three examples from that research are discussed. The first example deals with the vapour phase dimerisation of carboxylic acids and its consequences on phase equilibrium phenomena and phase equilibrium predictions. The second example deals with the solubility of sour gases (e.g., carbon dioxide and sulfur dioxide) in aqueous solutions of ammonia. That topic has been of interest for many years, e.g., in relation with the gasification and liquefaction of coal and, more recently, with the removal of carbon dioxide from flue gas in the 'chilled ammonia process'. The third example deals with phase equilibrium phenomena in aqueous solutions of polyelectrolytes. It deals with the phenomenon of 'counter ion condensation' and methods to model the Gibbs free energy of such solutions.

  16. ZIF-78 membrane derived from amorphous precursors with permselectivity for cyclohexanone/cyclohexanol mixture

    KAUST Repository

    Fan, Lili

    2014-07-01

    Cyclohexanone and cyclohexanol are products of selective oxidation of cyclohexane. They are important industrial intermediates and difficult to be separated due to their close boiling points. In this work, well-intergrown ZIF-78 membrane was successfully synthesized on the porous silica substrate by secondary growth method and applied for separation of cyclohexanone/cyclohexanol mixture for the first time. Meanwhile, a facile method for seeding procedure was developed by utilizing the amorphous ZIF-78 precursors to provide better-distributed nucleation sites. Both XRD and SEM results confirmed the good quality of the membrane. The pervaporation separation of cyclohexanone/ cyclohexanol mixture were carried out at room temperature with permselectivity of 1:2 and total flux around 8.7 × 10-2 kg m-2 h-1. © 2013 Elsevier Inc. All rights reserved.

  17. Separation of gaseous air pollutants using membrane contactors

    Science.gov (United States)

    Sverak, T.; Bulejko, P.; Ostrezi, J.; Kristof, O.; Kalivoda, J.; Kejik, P.; Mayerova, K.; Adamcik, M.

    2017-10-01

    This work deals with the separation of CO2 gaseous pollutant from gas mixtures to a water solution using the laboratory contactor. The laboratory set process parameters showed the rate of carbon dioxide transition through the interface in a so promising level the contactor separators can be considered as a very promising pathway to reduce the content of this greenhouse gas from the air.

  18. Separation and enrichment of enantiopure from racemic compounds using magnetic levitation.

    Science.gov (United States)

    Yang, Xiaochuan; Wong, Shin Yee; Bwambok, David K; Atkinson, Manza B J; Zhang, Xi; Whitesides, George M; Myerson, Allan S

    2014-07-18

    Crystallization of a solution with high enantiomeric excess can generate a mixture of crystals of the desired enantiomer and the racemic compound. Using a mixture of S-/RS-ibuprofen crystals as a model, we demonstrated that magnetic levitation (MagLev) is a useful technique for analysis, separation and enantioenrichment of chiral/racemic products.

  19. Using Pitch, Amplitude Modulation, and Spatial Cues for Separation of Harmonic Instruments from Stereo Music Recordings

    Directory of Open Access Journals (Sweden)

    Bryan Pardo

    2007-01-01

    Full Text Available Recent work in blind source separation applied to anechoic mixtures of speech allows for improved reconstruction of sources that rarely overlap in a time-frequency representation. While the assumption that speech mixtures do not overlap significantly in time-frequency is reasonable, music mixtures rarely meet this constraint, requiring new approaches. We introduce a method that uses spatial cues from anechoic, stereo music recordings and assumptions regarding the structure of musical source signals to effectively separate mixtures of tonal music. We discuss existing techniques to create partial source signal estimates from regions of the mixture where source signals do not overlap significantly. We use these partial signals within a new demixing framework, in which we estimate harmonic masks for each source, allowing the determination of the number of active sources in important time-frequency frames of the mixture. We then propose a method for distributing energy from time-frequency frames of the mixture to multiple source signals. This allows dealing with mixtures that contain time-frequency frames in which multiple harmonic sources are active without requiring knowledge of source characteristics.

  20. Study of extraction of rare earths by oil sulfoxides and their mixtures with tributyl phosphate

    International Nuclear Information System (INIS)

    Mikhlin, E.B.; Vol'dman, G.M.; Zelikman, A.N.; Novikova, N.N.

    1977-01-01

    Neodymium distribution is studied during its extraction from nitrate solutions with oil sulphoxides (OSO) and their mixtures with TBP in a wide range of neodymium and desalting agent (aluminium nitrate) concentrations. The extraction capacity of OSO is shown to considerably exceed that of TBP. A synergic effect due to formation of mixed solvates is observed at extraction with an OSO-TBP mixture. The separation coefficients (β) of the pairs Ce-La, Pr-Ce and Nd-Pr are determined. OSO and, especially, the OSO-TBP mixture are shown to be applicable for separating cerium and lanthanum, since the βsub(Ge/La) value for these extraction agents is higher than that for TBP, the extraction agent capacity attaining values that are acceptable for practival purposes

  1. Insertion of marble waste in the production chain of glass wool; Insercao do residuo de marmore na cadeia produtiva da la de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, G.F.; Alves, J.O.; Espinosa, D.C.R.; Tenorio, J.A.S., E-mail: girleyf@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    The work aimed the study of the recycle of the waste from marble cutting, aiming the reuse as partial raw material in the production of glass wool. Glass wool are materials with chemical and mechanical resistance, durability and lightness, and also important thermo-acoustic properties. A mixture of the waste with chemical additives was melted in a laboratory electric furnace using temperature of 1450 deg C. The melted material was directly poured in a water-filled recipient aiming the rapidly cooling. Samples of the produced material were characterized by XRD, SEM and DTA. The results showed that the residue from marble cutting can be inserted into the productive chain of glass wool, providing a decrease in the extraction of mineral resources, a profitable destination for this waste, and a economy for the companies producer of thermo-acoustic insulators. (author)

  2. Insertion of marble waste in the production chain of glass wool

    International Nuclear Information System (INIS)

    Rodrigues, G.F.; Alves, J.O.; Espinosa, D.C.R.; Tenorio, J.A.S.

    2010-01-01

    The work aimed the study of the recycle of the waste from marble cutting, aiming the reuse as partial raw material in the production of glass wool. Glass wool are materials with chemical and mechanical resistance, durability and lightness, and also important thermo-acoustic properties. A mixture of the waste with chemical additives was melted in a laboratory electric furnace using temperature of 1450 deg C. The melted material was directly poured in a water-filled recipient aiming the rapidly cooling. Samples of the produced material were characterized by XRD, SEM and DTA. The results showed that the residue from marble cutting can be inserted into the productive chain of glass wool, providing a decrease in the extraction of mineral resources, a profitable destination for this waste, and a economy for the companies producer of thermo-acoustic insulators. (author)

  3. Separation of zirconium (Zr) and hafnium (Hf) using solvent mixture of TBP-D_2EHPA and amberlite XAD-16

    International Nuclear Information System (INIS)

    Dwi Biyantoro; I Made Sukarna; Agus Suyanto

    2017-01-01

    The aims of this research were to determine the composition (ratio of extractant and resin) of the SIR which is effective for the separation of Zr and Hf, knowing adsorption equilibrium models Zr and Hf using the SIR, and knowing the most effective adsorption results from SIR weight ratio. The research was conducted by using the SIR method that is impregnating the extractant into the resin. Extractant used is a mixture of TBP and D_2EHPA (1 : 3), the resin used is XAD-16, and the feed used is ZOC. This research was conducted by varying the composition of the SIR, after the result of effective SIR variation. Adsorption process is then performed using the ZOC with SIR. Then filtered, the filtrate was analyzed by XRF. While solids SIR adsorption product was desorbed using sulfuric acid. Then the desorption results were analyzed using XRF spectrometer. Based on calculations, the results of the most effective SIR composition for the separation of Zr-Hf are comparison extractant and resin = 5:5 either for the dry method and wet method, the equilibrium equations for Zr approaching Langmuir equilibrium models while the equilibrium equation for Hf approaching Freundlich equilibrium models which the most effective adsorption results that bait comparison with the SIR = 10 mL : 5 g with β = 0.1831; η Zr = 26.39 % and η Hf = 66.19 % for dry method and β = 0.1557; η Zr = 25.17 % and η Hf = 68.36 % for wet method. From result desorption process was 2 M H_2SO_4. (author)

  4. An improved ion-exchange separation of rare-earth elements for spectrographic analysis

    International Nuclear Information System (INIS)

    Jones, E.A.

    1978-01-01

    Rare-earth elements are separated from scandium and base metals by adsorption onto anion resin BIORAD AG1-X8 in the nitrate form from a mixture of 5 per cent 7M nitric acid and 95 per cent methanol. The yttrium subgroup is eluted with a mixture of 45 per cent 7M nitric acid and 55 per cent methanol, followed by elution of the cerium subgroup with 8M nitric acid. This separation facilitates the determination of the traces of the heavier yttrium subgroup of rare-earth elements

  5. Method of isotope separation by chemi-ionization

    International Nuclear Information System (INIS)

    Wexler, S.; Young, C.E.

    1977-01-01

    A method is disclosed for separating isotopes in an isotopic mixture by aerodynamically accelerating a gaseous compound to form a jet of molecules, and passing the jet through a stream of electron donor atoms whereby an electron transfer takes place, thus forming negative ions of the molecules. The molecular ions are then passed through a radiofrequency quadrupole mass filter to separate the specific isotopes. cThis method may be used for any compounds having a sufficiently high electron affinity to permit negative ion formation, and is especially useful for the separation of plutonium and uranium isotopes. 10 claims, 1 figure

  6. Steady-state organization of binary mixtures by active impurities

    DEFF Research Database (Denmark)

    Sabra, Mads Christian; Gilhøj, Henriette; Mouritsen, Ole G.

    1998-01-01

    The structural reorganization of a phase-separated binary mixture in the presence of an annealed dilution of active impurities is studied by computer-simulation techniques via a simple two-dimensional lattice-gas model. The impurities, each of which has two internal states with different affinity...

  7. A Variational Statistical-Field Theory for Polar Liquid Mixtures

    Science.gov (United States)

    Zhuang, Bilin; Wang, Zhen-Gang

    Using a variational field-theoretic approach, we derive a molecularly-based theory for polar liquid mixtures. The resulting theory consists of simple algebraic expressions for the free energy of mixing and the dielectric constant as functions of mixture composition. Using only the dielectric constants and the molar volumes of the pure liquid constituents, the theory evaluates the mixture dielectric constants in good agreement with the experimental values for a wide range of liquid mixtures, without using adjustable parameters. In addition, the theory predicts that liquids with similar dielectric constants and molar volumes dissolve well in each other, while sufficient disparity in these parameters result in phase separation. The calculated miscibility map on the dielectric constant-molar volume axes agrees well with known experimental observations for a large number of liquid pairs. Thus the theory provides a quantification for the well-known empirical ``like-dissolves-like'' rule. Bz acknowledges the A-STAR fellowship for the financial support.

  8. Particle separation by phase modulated surface acoustic waves.

    Science.gov (United States)

    Simon, Gergely; Andrade, Marco A B; Reboud, Julien; Marques-Hueso, Jose; Desmulliez, Marc P Y; Cooper, Jonathan M; Riehle, Mathis O; Bernassau, Anne L

    2017-09-01

    High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.

  9. The separation of a mixture of bone marrow stem cells from tumor cells: an essential step for autologous bone marrow transplantation

    International Nuclear Information System (INIS)

    Rubin, P.; Wheeler, K.T.; Keng, P.C.; Gregory, P.K.; Croizat, H.

    1981-01-01

    KHT tumor cells were mixed with mouse bone marrow to simulate a sample of bone marrow containing metastatic tumor cells. This mixture was separated into a bone marrow fraction and a tumor cell fraction by centrifugal elutriation. Elutriation did not change the transplantability of the bone marrow stem cells as measured by a spleen colony assay and an in vitro erythroid burst forming unit assay. The tumorogenicity of the KHT cells was similarly unaffected by elutriation. The data showed that bone marrow cells could be purified to less than 1 tumor cell in more than 10 6 bone marrow cells. Therefore, purification of bone marrow removed prior to lethal radiation-drug combined therapy for subsequent autologous transplantation appears to be feasible using modifications of this method if similar physical differences between human metastatic tumor cells and human bone marrow cells exist. This possibility is presently being explored

  10. Large-scale separation of single-walled carbon nanotubes by electronic type using click chemistry

    Science.gov (United States)

    Um, Jo-Eun; Song, Sun Gu; Yoo, Pil J.; Song, Changsik; Kim, Woo-Jae

    2018-01-01

    Single-walled carbon nanotubes (SWCNTs) can be either metallic or semiconducting, making their separation critical for applications in nanoelectronics, biomedical materials, and solar cells. Herein, we investigate a novel solution-phase separation method based on click chemistry (azide-alkyne Huisgen cycloaddition) and determine its efficiency and scalability. In this method, metallic SWCNTs in metallic/semiconducting SWCNT mixtures are selectively functionalized with alkyne groups by being reacted with 4-propargyloxybenezenediazonium tetrafluoroborate. Subsequently, silica nanoparticles are functionalized with azide groups and reacted with alkyne-bearing metallic SWCNTs in the SWCNT mixture in the presence of a Cu catalyst. As a result, metallic SWCNTs are anchored on silica powder, whereas non-functionalized semiconducting SWCNTs remain in solution. Low-speed centrifugation effectively removes the silica powder with attached metallic SWCNTs, furnishing a solution of highly pure semiconducting SWCNTs, as confirmed by Raman and UV-vis/near-infrared absorption measurements. This novel separation scheme exhibits the advantage of simultaneously separating both metallic and semiconducting SWCNTs from their mixtures, being cost-effective and therefore applicable at an industrial scale.

  11. Composition shift in liquid-recirculation refrigerating systems: an experimental investigation for the pure fluid R134a and the mixture R32/134a

    Energy Technology Data Exchange (ETDEWEB)

    Giuliani, G.; Marchesi Donati, F.; Polonara, F. [Ancona Univ. (Italy). Dip. di Energetica; Hewitt, N.J. [University of Ulster at Coleraine, Northern Ireland (United Kingdom). NICERT

    1999-09-01

    The ability of zeotropic mixtures with a remarkable temperature glide to operate in liquid-recirculation systems is investigated and the results of an experimental comparison between the performances of the pure fluid R134a and the zeotropic mixture R32/134a (25/75% by mass) are presented. R134a performs slightly better in the liquid-recirculation mode than in the traditional dry-expansion mode; on the other hand, liquid-recirculation configuration has a detrimental effect on the zeotropic mixture's performance. The reason for this detrimental effect is the mixture component separation which occurs at the liquid/vapor separator. The effect of this separation is investigated using gas chromatograph analysis.

  12. Energy expenditures of plasma method of isotope separation

    International Nuclear Information System (INIS)

    Karchevskij, A.I.; Potanin, E.P.

    1986-01-01

    The estimations are performed of specific energy expenditares in isotope separation of binary mixtures in different plasma systems with weak medium ionization (plasma centrifuge, gas discharge system with travelling magnetic field, direct current discharge). Potential advantages of plasma centrifuge over other gas discharge facilities are pointed out. The comparison of specific energy expenditure values in case of using plasma and conventional methods of isotope separation is carried out

  13. Separation of hydrogen isotopes for tritium waste removal

    International Nuclear Information System (INIS)

    Wilkes, W.R.

    1975-01-01

    A distillation cascade for separating hydrogen isotopes was simulated by means of a multicomponent, multistage computer code. A hypothetical test mixture containing equal atomic fractions of protium, deuterium and tritium, equilibrated to high temperature molecular concentrations was used as feed. The results show that a two-column cascade can be used to separate the protium from the tritium. Deuterium appears both in the protium and the tritium product streams. (auth)

  14. Gyroidal nanoporous carbons - Adsorption and separation properties explored using computer simulations

    Directory of Open Access Journals (Sweden)

    S. Furmaniak

    2016-02-01

    Full Text Available Adsorption and separation properties of gyroidal nanoporous carbons (GNCs - a new class of exotic nanocarbon materials are studied for the first time using hyper parallel tempering Monte Carlo Simulation technique. Porous structure of GNC models is evaluated by the method proposed by Bhattacharya and Gubbins. All the studied structures are strictly microporous. Next, mechanisms of Ar adsorption are described basing on the analysis of adsorption isotherms, enthalpy plots, the values of Henry’s constants, α_{s} and adsorption potential distribution plots. It is concluded that below pore diameters ca. 0.8 nm, primary micropore filling process dominates. For structures possessing larger micropores, primary and secondary micropore filling mechanism is observed. Finally, the separation properties of GNC toward CO_{2}/CH_{4}, CO_{2}/N_{2}, and CH_{4}/N_{2} mixtures are discussed and compared with separation properties of Virtual Porous Carbon models. GNCs may be considered as potential adsorbents for gas mixture separation, having separation efficiency similar or even higher than activated carbons with similar diameters of pores.

  15. Separative power of an optimised concurrent gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, Sergey; Boman, Vladimir [National Research Nuclear University (MEPHI), Moscow (Russian Federation)

    2016-06-15

    The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  16. Phase separation phenomena in branching conduits. Topical report Dec 78-Dec 81

    International Nuclear Information System (INIS)

    Saba, N.; Lahey, R.T. Jr.

    1982-03-01

    The analysis of Light Water Reactor (LWR) Loss-of-Coolant Accidents (LOCA's) requires that one be able to accurately calculate the two-phase flow splits in complex, branching conduits. The purpose of this study is to provide a general method for calculating the phase separation in a branching conduit. The degree of phase separation of a two-phase (air/water) mixture flowing through a plexiglas tee test section was measured. In addition, flow visualization, using high speed photography, was performed. The experimental design considerations, error analysis and the dependence of the observed phase separation on global parameters, such as inlet quality, mass flux and separation angle, are discussed. The pressure gradients were measured along the various conduits and the differential pressure was obtained at the tee junction by extrapolation. It was found that the degree of phase separation was quite pronounced, with the vapor phase preferentially separating into the branch. Using these data, a physically-based empirical model was developed with which to calculate the phasic distribution of a subsonic two-phase mixture in the downstream branches of a branching conduit

  17. Magnetic separations: From steel plants to biotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Cafer T. Yavuz; Arjun Prakash; J.T. Mayo; Vicki L. Colvin [Rice University, Houston, TX (United States). Department of Chemistry

    2009-05-15

    Magnetic separations have for decades been essential processes in diverse industries ranging from steel production to coal desulfurization. In such settings magnetic fields are used in continuous flow processes as filters to remove magnetic impurities. High gradient magnetic separation (HGMS) has found even broader use in wastewater treatment and food processing. Batch scale magnetic separations are also relevant in industry, particularly biotechnology where fixed magnetic separators are used to purify complex mixtures for protein isolation, cell separation, drug delivery, and biocatalysis. In this review, we introduce the basic concepts behind magnetic separations and summarize a few examples of its large scale application. HGMS systems and batch systems for magnetic separations have been developed largely in parallel by different communities. However, in this work we compare and contrast each approach so that investigators can approach both key areas. Finally, we discuss how new advances in magnetic materials, particularly on the nanoscale, as well as magnetic filter design offer new opportunities for industries that have challenging separation problems.

  18. Pump Propels Liquid And Gas Separately

    Science.gov (United States)

    Harvey, Andrew; Demler, Roger

    1993-01-01

    Design for pump that handles mixtures of liquid and gas efficiently. Containing only one rotor, pump is combination of centrifuge, pitot pump, and blower. Applications include turbomachinery in powerplants and superchargers in automobile engines. Efficiencies lower than those achieved in separate components. Nevertheless, design is practical and results in low consumption of power.

  19. Ionic liquids in separations of azeotropic systems – A review

    International Nuclear Information System (INIS)

    Pereiro, A.B.; Araújo, J.M.M.; Esperança, J.M.S.S.; Marrucho, I.M.; Rebelo, L.P.N.

    2012-01-01

    Highlights: ► This paper provides a review of methods using ionic liquids as azeotrope breakers. ► Azeotrope breaking potential of ILs was compared to that of conventional solvents. ► The influence of ILs structure on the azeotrope breaking capacity was accomplished. ► Guidelines to select the most suitable ILs as azeotrope breakers were established. - Abstract: Efforts to make existing separation methods more efficient and eco-friendly may get a boost from the use of a relatively new class of compounds known as ionic liquids (ILs). The separation of azeotropic mixtures has conventionally been one of the most challenging tasks in industrial processes due to the fact that their separation by simple distillation is basically impossible. This paper provides a critical review of methods using ILs as azeotrope breakers. Three separation processes were addressed: liquid–liquid extraction, extractive distillation, and supported liquid membranes. We examine the azeotrope breaking potential of ILs and compare their performance to that of conventional solvents. A systematic analysis of the influence of the structure of ILs on their azeotrope breaking capacity contributes to the establishment of guidelines for selecting the most suitable ILs for the separation of specific azeotropic mixtures.

  20. Separation of zirconium--hafnium by nitride precipitation

    International Nuclear Information System (INIS)

    Anderson, R.N.; Parlee, N.A.

    1977-01-01

    A method is described for the separation of a light reactive metal (e.g., zirconium) from a heavy reactive metal (e.g., hafnium) by forming insoluble nitrides of the metals in a molten metal solvent (e.g., copper) inert to nitrogen and having a suitable density for the light metal nitride to form a separate phase in the upper portion of the solvent and for the heavy metal nitride to form a separate phase in the lower portion of the solvent. Nitriding is performed by maintaining a nitrogen-containing atmosphere over the bath. The light and heavy metals may be an oxide mixture and carbothermically reduced to metal form in the same bath used for nitriding. The nitrides are then separately removed and decomposed to form the desired separate metals. 16 claims, 1 figure