WorldWideScience

Sample records for cooling crystallization process

  1. Investigation of lactose crystallization process during condensed milk cooling using native vacuum-crystallizer

    Directory of Open Access Journals (Sweden)

    E. I. Dobriyan

    2016-01-01

    Full Text Available One of the most general defects of condensed milk with sugar is its consistency heterogeneity – “candying”. The mentioned defect is conditioned by the presence of lactose big crystals in the product. Lactose crystals size up to 10 µm is not organoleptically felt. The bigger crystals impart heterogeneity to the consistency which can be evaluated as “floury”, “sandy”, “crunch on tooth”. Big crystals form crystalline deposit on the can or industrial package bottom in the form of thick layer. Industrial processing of the product with the defective process of crystallization results in the expensive equipment damage of the equipment at the confectionary plant accompanied with heavy losses. One of the factors influencing significantly lactose crystallization is the product cooling rate. Vacuum cooling is the necessary condition for provision of the product consistency homogeneity. For this purpose the vacuum crystallizers of “Vigand” company, Germany, are used. But their production in the last years has been stopped. All-Russian dairy research institute has developed “The references for development of the native vacuum crystallizer” according to which the industrial model has been manufactured. The produced vacuum – crystallizer test on the line for condensed milk with sugar production showed that the product cooling on the native vacuum-crystallizer guarantees production of the finished product with microstructure meeting the requirements of State standard 53436–2009 “Canned Milk. Milk and condensed cream with sugar”. The carried out investigations evidences that the average lactose crystals size in the condensed milk with sugar cooled at the native crystallizer makes up 6,78 µm. The granulometric composition of the product crystalline phase cooled at the newly developed vacuum-crystallizer is completely identical to granulometric composition of the product cooled at “Vigand” vacuum-crystallizer.

  2. Temperature and thermal stress evolutions in sapphire crystal during the cooling process by heat exchanger method

    Science.gov (United States)

    Ma, Wencheng; Zhao, Wenhan; Wu, Ming; Ding, Guoqiang; Liu, Lijun

    2017-09-01

    Transient numerical calculations were carried out to predict the evolutions of temperature and thermal stress in sapphire single crystal during the cooling process by heat exchanger method (HEM). Internal radiation in the semitransparent sapphire crystal was taken into account using the finite volume method (FVM) in the global heat transfer model. The numerical results seem to indicate that the narrow bottom region of the sapphire crystal is subjected to high thermal stress during the cooling process, which could be responsible for the seed cracking of the as-grown crystal, while the thermal stress is relatively small in the central main body of the crystal, and is less than 10 MPa during the whole cooling process. The fast decrease of the thermal stress in the bottom region of the crystal during the initial stage of cooling process is dominated by the reduction of the cooling helium gas in the heat exchanger shaft, and is not significantly affected by the heating power reduction rate.

  3. Estimating Influence of Crystallizing Latent Heat on Cooling-Crystallizing Process of a Granitic Melt and Its Geological Implications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bangtong; WU Junqi; LING Hongfei; CHEN Peirong

    2008-01-01

    Based on the theory of thermal conductivity, in this paper we derived a formula to estimate the prolongation period (AtL) of cooling-crystallization process of a granitic melt caused by latent heat of crystallization as follows: △t=QL×△tcol/TM-TC×CP where TM is initial temperature of the granite melt, Tc crystallization temperature of the granite melt,CP specific heat, △tcol cooling period of a granite melt from its initial temperature (TM) to its crystallization temperature (TC), QL latent heat of the granite melt. The cooling period of the melt for the Fanshan granodiorite from its initial temperature (900℃) to crystallization temperature (600℃) could be estimated ~210,000 years if latent heat was not considered. Calculation for the Fanshan melt using the above formula yields a AtL value of~190,000 years, which implies that the actual cooling period within the temperature range of 900℃-600℃ should be 400,000 years. This demonstrates that the latent heat produced from crystallization of the granitic melt is a key factor influencing the cooling-crystallization process of a granitic melt, prolongating the period of crystallization and resulting in the large emplacement-crystallization time difference (ECTD) in granite batholith.

  4. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, Dario, E-mail: Dario.cavallo@unige.it [University of Genoa, Dept. of Chemistry and Industrial Chemistry, Via Dodecaneso 31, 16146 Genoa (Italy); Portale, Giuseppe [ESRF, Dubble CRG, Netherlands Organization of Scientific Research (NWO), 38043 Grenoble (France); Androsch, René [Martin-Luther-University Halle-Wittenberg, Center of Engineering Sciences, D-06099 Halle/S. (Germany)

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  5. Nucleation control and separation of paracetamol polymorphs through swift cooling crystallization process

    Science.gov (United States)

    Sudha, C.; Srinivasan, K.

    2014-09-01

    Polymorphic nucleation behavior of pharmaceutical solid paracetamol has been investigated by performing swift cooling crystallization process. Saturated aqueous solution prepared at 318 K was swiftly cooled to 274 K in steps of every 1 K in the temperature range from 274 K to 313 K with uniform stirring of 100 rpm. The resultant supersaturation generated in the mother solution favours the nucleation of three different polymorphs of paracetamol. Lower supersaturation region σ=0.10-0.83 favours stable mono form I; the intermediate supersaturation region σ=0.92-1.28 favours metastable ortho form II and the higher supersaturation region σ=1.33-1.58 favours unstable form III polymorphic nucleation. Depending upon the level of supersaturation generated during swift cooling process and the corresponding solubility limit and metastable zone width (MSZW) of each polymorph, the nucleation of a particular polymorph occurs in the system. The type of polymorphs was identified by in-situ optical microscopy and the internal structure was confirmed by Powder X-ray diffraction (PXRD) study. By this novel approach, the preferred nucleation regions of all the three polymorphs of paracetamol are optimized in terms of different cooling ranges employed during the swift cooling process. Also solution mediated polymorphic transformations from unstable to mono and ortho to mono polymorphs have been studied by in-situ.

  6. Numerical analysis of dislocation density and residual stress in a GaN single crystal during the cooling process

    Science.gov (United States)

    Nakano, S.; Gao, B.; Kakimoto, K.

    2017-06-01

    In this study, we investigate the influence of thermal stress on the dislocation density and residual stress in GaN single crystals by numerical analysis. The results show that the dislocation density increases, but the thermal stress does not decrease, and the residual stress increases throughout the cooling process. The reason for this phenomenon is that the dislocation density is higher at the periphery of the crystal and distribution of dislocation density in the crystal is inhomogeneous. Then, the increase of dislocation does not allow the thermal stress on the entire crystal to relax.

  7. Crystallization and Mechanical Properties of Polypropylene under Processing-Relevant Cooling Conditions with respect to Isothermal Holding Time

    Directory of Open Access Journals (Sweden)

    Christopher Fischer

    2016-01-01

    Full Text Available For semicrystalline thermoplastics, aside from pressure and shear, the temperature-time behavior while cooling the melt significantly affects the geometry and degree of ordered structures (e.g., spherulite size, degree of crystallization, and crystal modification and, as a consequence, the resulting global component properties. Previous research has shown that a higher isothermal holding temperature (e.g., mold temperature and chill-roll temperature leads to the formation of more distinct ordered structures and, therefore, can lead to greater stiffness and strength. Nevertheless, isothermal holding time during manufacturing is typically not taken into account. In this paper, fast scanning calorimetry (FSC measurements were taken using polypropylene to analyze the crystallization during idealized temperature-time profiles based on the dynamic temperature process and to investigate the crystallization behavior at different temperatures and isothermal holding times analytically. Furthermore, iPP foils were extruded and tested mechanically to investigate the knowledge gained experimentally. Analytical and mechanical results show that foils produced at the same isothermal holding temperature can obtain significantly different ordered structures and mechanical properties depending primarily on the isothermal holding time.

  8. Batch cooling crystallization and pressure filtration of sulphathiazole

    DEFF Research Database (Denmark)

    Häkkinen, Antti; Pöllänen, Kati; Karjalainen, Milja

    2005-01-01

    crystal suspensions obtained through an unseeded batch-cooling-crystallization process was studied. Sulphathiazole, which is an antibiotic agent with multiple polymorphic forms, was produced by performing laboratory-scale cooling crystallization experiments from five different mixtures of water and propan...

  9. Crystallization and Mechanical Properties of Polypropylene under Processing-Relevant Cooling Conditions with respect to Isothermal Holding Time

    OpenAIRE

    Christopher Fischer; Dietmar Drummer

    2016-01-01

    For semicrystalline thermoplastics, aside from pressure and shear, the temperature-time behavior while cooling the melt significantly affects the geometry and degree of ordered structures (e.g., spherulite size, degree of crystallization, and crystal modification) and, as a consequence, the resulting global component properties. Previous research has shown that a higher isothermal holding temperature (e.g., mold temperature and chill-roll temperature) leads to the formation of more distinct o...

  10. Crystallization process

    Science.gov (United States)

    Adler, Robert J.; Brown, William R.; Auyang, Lun; Liu, Yin-Chang; Cook, W. Jeffrey

    1986-01-01

    An improved crystallization process is disclosed for separating a crystallizable material and an excluded material which is at least partially excluded from the solid phase of the crystallizable material obtained upon freezing a liquid phase of the materials. The solid phase is more dense than the liquid phase, and it is separated therefrom by relative movement with the formation of a packed bed of solid phase. The packed bed is continuously formed adjacent its lower end and passed from the liquid phase into a countercurrent flow of backwash liquid. The packed bed extends through the level of the backwash liquid to provide a drained bed of solid phase adjacent its upper end which is melted by a condensing vapor.

  11. Doppler cooling of a Coulomb crystal

    CERN Document Server

    Morigi, G; Morigi, Giovanna; Eschner, Juergen

    2001-01-01

    We study theoretically Doppler laser-cooling of a cluster of 2-level atoms confined in a linear ion trap. Using several consecutive steps of averaging we derive, from the full quantum mechanical master equation, an equation for the total mechanical energy of the one dimensional crystal, defined on a coarse-grained energy scale whose grid size is smaller than the linewidth of the electronic transition. This equation describes the cooling dynamics for an arbitrary number of ions and in the quantum regime. We discuss the validity of the ergodic assumption (i.e. that the phase space distribution is only a function of energy). From our equation we derive the semiclassical limit (i.e. when the mechanical motion can be treated classically) and the Lamb-Dicke limit (i.e. when the size of the mechanical wave function is much smaller than the laser wavelength). We find a Fokker-Planck equation for the total mechanical energy of the system, whose solution is in agreement with previous analytical calculations which were ...

  12. Colouring cryo-cooled crystals: online microspectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    McGeehan, John [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); Biophysics Laboratories, School of Biological Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth PO1 2DY (United Kingdom); Ravelli, Raimond B. G., E-mail: ravelli@lumc.nl [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); Section Electron Microscopy, Department of Molecular Cell Biology, Leiden University Medical Center (LUMC), PO Box 9600, 2300RC Leiden (Netherlands); Murray, James W. [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Imperial College, Exhibition Road, London SW7 2AZ (United Kingdom); Owen, Robin Leslie [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Cipriani, Florent [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); McSweeney, Sean [ESRF, 6 rue Jules Horowitz, 38043 Grenoble (France); Weik, Martin [Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, Jean Pierre EBEL, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1 (France); Garman, Elspeth F., E-mail: ravelli@lumc.nl [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom)

    2009-03-01

    A portable and readily aligned online microspectrophotometer that can be easily installed on macromolecular crystallography beamlines is described. It allows measurement of the spectral characteristics of macromolecular crystals prior, during, and after the X-ray diffraction experiment. X-rays can produce a high concentration of radicals within cryo-cooled macromolecular crystals. Some radicals have large extinction coefficients in the visible (VIS) range of the electromagnetic spectrum, and can be observed optically and spectrally. An online microspectrophotometer with high temporal resolution has been constructed that is capable of measuring UV/VIS absorption spectra (200–1100 nm) during X-ray data collection. The typical X-ray-induced blue colour that is characteristic of a wide range of cryo-conditions has been identified as trapped solvated electrons. Disulphide-containing proteins are shown to form disulphide radicals at millimolar concentrations, with absorption maxima around 400 nm. The solvated electrons and the disulphide radicals seem to have a lifetime in the range of seconds up to minutes at 100 K. The temperature dependence of the kinetics of X-ray-induced radical formation is different for the solvated electrons compared with the disulphide radicals. The online microspectrophotometer provides a technique complementary to X-ray diffraction for analysing and characterizing intermediates and redox states of proteins and enzymes.

  13. Use of focused beam reflectance measurement (FBRM) and process video imaging (PVI) in a modified mixed suspension mixed product removal (MSMPR) cooling crystallizer

    Science.gov (United States)

    Kougoulos, E.; Jones, A. G.; Jennings, K. H.; Wood-Kaczmar, M. W.

    2005-01-01

    The FBRM instrument is a 'powerful' tool developed by Lasentec as an 'in situ' particle monitoring technique for in-line real-time measurement of particle size. This technique was successfully used to monitor steady-state operation in a modified MSMPR crystallizer. The FBRM technique was also used to estimate crystallization kinetics. The FBRM particle size measurements were complimented by an in-line process video imaging (PVI) system developed ' in-house' (Microscopy and Microanalysis, 6 (Suppl. 2) (2000) 996-997), to visualize habit and crystal behaviour within an MSMPR crystallizer. A comparison of the steady-state crystal size distributions measured by low angle light scattering (LALLS) and FBRM was made, showing poor sensitivity of the FBRM technique to particles of less than 1 μm hence the technique was not suitable for the measurement of crystallization kinetics for this organic system.

  14. Continuous preparation of polymer coated drug crystals by solid hollow fiber membrane-based cooling crystallization.

    Science.gov (United States)

    Chen, Dengyue; Singh, Dhananjay; Sirkar, Kamalesh K; Pfeffer, Robert

    2016-02-29

    A facile way to continuously coat drug crystals with a polymer is needed in controlled drug release. Conventional polymer coating methods have disadvantages: high energy consumption, low productivity, batch processing. A novel method for continuous polymer coating of drug crystals based on solid hollow fiber cooling crystallization (SHFCC) is introduced here. The drug acting as the host particle and the polymer for coating are Griseofulvin (GF) and Eudragit RL100, respectively. The polymer's cloud point temperature in its acetone solution was determined by UV spectrophotometry. An acetone solution of the polymer containing the drug in solution as well as undissolved drug crystals in suspension were pumped through the tube side of the SHFCC device; a cold liquid was circulated in the shell side to rapidly cool down the feed solution-suspension in the hollow-fiber lumen. The polymer precipitated from the solution and coated the suspended crystals due to rapid temperature reduction and heterogeneous nucleation; crystals formed from the solution were also coated by the polymer. Characterizations by scanning electron microscopy, thermogravimetric analysis, laser diffraction spectroscopy, X-ray diffraction, Raman spectroscopy, and dissolution tests show that a uniformly coated, free-flowing drug/product can be obtained under appropriate operating conditions without losing the drug's pharmaceutical properties and controlled release characteristics.

  15. Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnel, Matthias

    2014-02-15

    This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

  16. Effect of cooling rate on crystallization in an aluminophosphosilicate melt

    DEFF Research Database (Denmark)

    Liu, S. J.; Zhang, Yanfei; Yue, Yuanzheng

    2011-01-01

    The effect of cooling rate on spontaneous crystallization behavior of an alumino-phospho-silicate melt is studied by means of differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and viscometry. The cooling rates of 160, 2100 and 12000 K/s are attained by subjecting...

  17. Effect of cooling rate on crystallization in an aluminophosphosilicate melt

    DEFF Research Database (Denmark)

    Liu, S. J.; Zhang, Yanfei; Yue, Yuanzheng

    2011-01-01

    The effect of cooling rate on spontaneous crystallization behavior of an alumino-phospho-silicate melt is studied by means of differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and viscometry. The cooling rates of 160, 2100 and 12000 K/s are attained by subjecting...

  18. Vibrational relaxation and vibrational cooling in low temperature molecular crystals

    Science.gov (United States)

    Hill, Jeffrey R.; Chronister, Eric L.; Chang, Ta-Chau; Kim, Hackjin; Postlewaite, Jay C.; Dlott, Dana D.

    1988-01-01

    The processes of vibrational relaxation (VR) and vibrational cooling (VC) are investigated in low temperature crystals of complex molecules, specifically benzene, naphthalene, anthracene, and durene. In the VR process, a vibration is deexcited, while VC consists of many sequential and parallel VR steps which return the crystal to thermal equilibrium. A theoretical model is developed which relates the VR rate to the excess vibrational energy, the molecular structure, and the crystal structure. Specific relations are derived for the vibrational lifetime T1 in each of three regimes of excess vibrational energy. The regimes are the following: Low frequency regime I where VR occurs by emission of two phonons, intermediate frequency regime II where VR occurs by emission of one phonon and one vibration, and high frequency regime III where VR occurs by evolution into a dense bath of vibrational combinations. The VR rate in each regime depends on a particular multiphonon density of states and a few averaged anharmonic coefficients. The appropriate densities of states are calculated from spectroscopic data, and together with available VR data and new infrared and ps Raman data, the values of the anharmonic coefficients are determined for each material. The relationship between these parameters and the material properties is discussed. We then describe VC in a master equation formalism. The transition rate matrix for naphthalene is found using the empirically determined parameters of the above model, and the time dependent redistribution in each mode is calculated.

  19. Structural evolution in the crystallization of rapid cooling silver melt

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Z.A., E-mail: ze.tian@gmail.com [School of Physics and Electronics, Hunan University, Changsha 410082 (China); Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Dong, K.J.; Yu, A.B. [Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

    2015-03-15

    The structural evolution in a rapid cooling process of silver melt has been investigated at different scales by adopting several analysis methods. The results testify Ostwald’s rule of stages and Frank conjecture upon icosahedron with many specific details. In particular, the cluster-scale analysis by a recent developed method called LSCA (the Largest Standard Cluster Analysis) clarified the complex structural evolution occurred in crystallization: different kinds of local clusters (such as ico-like (ico is the abbreviation of icosahedron), ico-bcc like (bcc, body-centred cubic), bcc, bcc-like structures) in turn have their maximal numbers as temperature decreases. And in a rather wide temperature range the icosahedral short-range order (ISRO) demonstrates a saturated stage (where the amount of ico-like structures keeps stable) that breeds metastable bcc clusters. As the precursor of crystallization, after reaching the maximal number bcc clusters finally decrease, resulting in the final solid being a mixture mainly composed of fcc/hcp (face-centred cubic and hexagonal-closed packed) clusters and to a less degree, bcc clusters. This detailed geometric picture for crystallization of liquid metal is believed to be useful to improve the fundamental understanding of liquid–solid phase transition. - Highlights: • A comprehensive structural analysis is conducted focusing on crystallization. • The involved atoms in our analysis are more than 90% for all samples concerned. • A series of distinct intermediate states are found in crystallization of silver melt. • A novelty icosahedron-saturated state breeds the metastable bcc state.

  20. Enhancement of heat transfer in Czochralski growth of silicon crystals with a chemical cooling technique

    Science.gov (United States)

    Ding, Junling; Liu, Lijun; Zhao, Wenhan

    2017-06-01

    The cost of producing single-crystalline silicon with the Czochralski method can be reduced by promoting the crystal size and/or crystal pulling rate. However, more latent heat of solidification needs to be released from the melt-crystal (m-c) interface during the crystal growth process. In this study, the C-CO2 chemical endothermic reaction is proposed as a novel and efficient cooling technique to solve this problem. Compared with the conventional gas cooling method, C-CO2 endothermic reaction method can significantly enhance the heat transfer in the crystal at the m-c interface. It was found that the heat transfer is more enhanced with a chemical reaction of smaller activation energy, and the m-c interface becomes flatter. The influence of the carbon concentration in the chemical reactive gas flow on the heat removal in the crystal at the m-c interface is also investigated. The cooling effect is significantly increased with the increase in the carbon concentration when it is small. However, when the carbon concentration in the reactive gas is high, the cooling effect just increases slightly. The research demonstrates that the proposed chemical endothermic reaction is a promising cooling technique to be applied in CZ-Si crystal growth with large size/high pulling rate.

  1. Couette-Taylor crystallizer: Effective control of crystal size distribution and recovery of L-lysine in cooling crystallization

    Science.gov (United States)

    Nguyen, Anh-Tuan; Yu, Taekyung; Kim, Woo-Sik

    2017-07-01

    A Couette-Taylor crystallizer is developed to enhance the L-Lysine crystal size distribution and recovery in the case of continuous cooling crystallization. When using the proposed Couette-Taylor (CT) crystallizer, the size distribution and crystal product recovery were much narrower and higher, respectively, than those from a conventional stirred tank (ST) crystallizer. Here, the coefficient of the size distribution for the crystal product from the CT crystallizer was only 0.45, while it was 0.78 in the case of the conventional ST crystallizer at an agitation speed of 700 rpm, mean residence time of 20 min, and feed concentration of 900 (g/L). Furthermore, when using the CT crystallizer, the crystal product recovery was remarkably enhanced up to 100%wt with a mean residence time of only 20 min, while it required a mean residence time of at least 60 min when using the conventional ST crystallizer. This result indicates that the CT crystallizer was much more effective than the conventional ST crystallizer in terms of controlling a narrower size distribution and achieving a 100%wt L-lysine crystal product recovery from continuous cooling crystallization. The advantage of the CT crystallizer over the conventional ST crystallizer was explained based on the higher energy dissipation of the Taylor vortex flow and larger surface area for heat transfer of the CT crystallizer. Here, the energy dissipation of the Taylor vortex flow in the CT crystallizer was 13.6 times higher than that of the random fluid motion in the conventional ST crystallizer, while the surface area per unit volume for heat transfer of the CT crystallizer was 8.0 times higher than that of the conventional ST crystallizer. As a result, the mixing condition and heat transfer of the CT crystallizer were much more effective than those of the conventional ST crystallizer for the cooling crystallization of L-lysine, thereby enhancing the L-lysine crystal size distribution and product recovery.

  2. Comparative study on ATR-FTIR calibration models for monitoring solution concentration in cooling crystallization

    Science.gov (United States)

    Zhang, Fangkun; Liu, Tao; Wang, Xue Z.; Liu, Jingxiang; Jiang, Xiaobin

    2017-02-01

    In this paper calibration model building based on using an ATR-FTIR spectroscopy is investigated for in-situ measurement of the solution concentration during a cooling crystallization process. The cooling crystallization of L-glutamic Acid (LGA) as a case is studied here. It was found that using the metastable zone (MSZ) data for model calibration can guarantee the prediction accuracy for monitoring the operating window of cooling crystallization, compared to the usage of undersaturated zone (USZ) spectra for model building as traditionally practiced. Calibration experiments were made for LGA solution under different concentrations. Four candidate calibration models were established using different zone data for comparison, by using a multivariate partial least-squares (PLS) regression algorithm for the collected spectra together with the corresponding temperature values. Experiments under different process conditions including the changes of solution concentration and operating temperature were conducted. The results indicate that using the MSZ spectra for model calibration can give more accurate prediction of the solution concentration during the crystallization process, while maintaining accuracy in changing the operating temperature. The primary reason of prediction error was clarified as spectral nonlinearity for in-situ measurement between USZ and MSZ. In addition, an LGA cooling crystallization experiment was performed to verify the sensitivity of these calibration models for monitoring the crystal growth process.

  3. Three-dimensional analysis of dislocation multiplication in single-crystal silicon under accurate control of cooling history of temperature

    Science.gov (United States)

    Gao, B.; Kakimoto, K.

    2014-06-01

    Dislocation multiplication in single-crystal silicon during heating and cooling processes was studied by three-dimensional simulation under accurate control of the temperature history. Three different cooling temperature histories were designed. The results showed that the cooling rate in the high-temperature region has a large effect on the final dislocations and residual stress. The most effective method to reduce dislocations is to use a slow cooling rate in the high-temperature region.

  4. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  5. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  6. Crystallization of Al-Zr alloys at high cooling rates

    Energy Technology Data Exchange (ETDEWEB)

    Toropova, L.S.; Kamardinkin, A.N.

    1989-01-01

    The nonequilibrium crystallization of Al-Zr alloys containing up to 5 mass pct Zr is investigated by light and electron microscopy and on the basis of lattice spacing and electrical conductivity measurements. A phase diagram of the system is presented. The dependence of the dendritic parameters of Al-Zr alloys on the cooling rate is demonstrated. 10 references.

  7. Angular vibrations of cryogenically cooled double-crystal monochromators.

    Science.gov (United States)

    Sergueev, I; Döhrmann, R; Horbach, J; Heuer, J

    2016-09-01

    The effect of angular vibrations of the crystals in cryogenically cooled monochromators on the beam performance has been studied theoretically and experimentally. A simple relation between amplitude of the vibrations and size of the focused beam is developed. It is shown that the double-crystal monochromator vibrations affect not only the image size but also the image position along the optical axis. Several methods to measure vibrations with the X-ray beam are explained and analyzed. The methods have been applied to systematically study angular crystal vibrations at monochromators installed at the PETRA III light source. Characteristic values of the amplitudes of angular vibrations for different monochromators are presented.

  8. Investigation of the operating conditions to morphology evolution of β-L-glutamic acid during seeded cooling crystallization

    Science.gov (United States)

    Zhang, Fangkun; Liu, Tao; Huo, Yan; Guan, Runduo; Wang, Xue Z.

    2017-07-01

    In this paper the effects of operating conditions including cooling rate, initial supersaturation, and seeding temperature were investigated on the morphology evolution of β-L-glutamic acid (β-LGA) during seeded cooling crystallization. Based on the results of in-situ image acquisition of the crystal morphology evolution during the crystallization process, it was found that the crystal products tend to be plate-like or short rod-like under a slow cooling rate, low initial supersaturation, and low seeding temperature. In the opposite, the operating conditions of a faster cooling rate, higher initial supersaturation, and higher seeding temperature tend to produce long rod-like or needle-like crystals, and meanwhile, the length and width of crystal products will be increased together with a wider crystal size distribution (CSD). The aspect ratio of crystals, defined by the crystal length over width measured from in-situ or sample images, was taken as a shape index to analyze the crystal morphologies. Based on comparative analysis of the experimental results, guidelines on these operating conditions were given for obtaining the desired crystal shapes, along with the strategies for obtaining a narrower CSD for better product quality. Experimental verifications were performed to illustrate the proposed guidelines on the operating conditions for seeded cooling crystallization of LGA solution.

  9. Asymmetric crystallization during cooling and heating in model glass-forming systems.

    Science.gov (United States)

    Wang, Minglei; Zhang, Kai; Li, Zhusong; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D; O'Hern, Corey S

    2015-03-01

    We perform molecular dynamics (MD) simulations of the crystallization process in binary Lennard-Jones systems during heating and cooling to investigate atomic-scale crystallization kinetics in glass-forming materials. For the cooling protocol, we prepared equilibrated liquids above the liquidus temperature Tl and cooled each sample to zero temperature at rate Rc. For the heating protocol, we first cooled equilibrated liquids to zero temperature at rate Rp and then heated the samples to temperature T>Tl at rate Rh. We measured the critical heating and cooling rates Rh* and Rc*, below which the systems begin to form a substantial fraction of crystalline clusters during the heating and cooling protocols. We show that Rh*>Rc* and that the asymmetry ratio Rh*/Rc* includes an intrinsic contribution that increases with the glass-forming ability (GFA) of the system and a preparation-rate dependent contribution that increases strongly as Rp→Rc* from above. We also show that the predictions from classical nucleation theory (CNT) can qualitatively describe the dependence of the asymmetry ratio on the GFA and preparation rate Rp from the MD simulations and results for the asymmetry ratio measured in Zr- and Au-based bulk metallic glasses (BMG). This work emphasizes the need for and benefits of an improved understanding of crystallization processes in BMGs and other glass-forming systems.

  10. Integration of Generic Multi-dimensional Model and Operational Policies for Batch Cooling Crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    2011-01-01

    A generic multi-dimensional modeling framework for studying batch cooling crystallization processes under generated operational policies is presented. The generic nature of the modeling allows the study of a wide range of chemical systems under different operational scenarios, enabling thereby, t...

  11. Batch cooling crystallization and pressure filtration of sulphathiazole: the influence of solvent composition.

    Science.gov (United States)

    Häkkinen, Antti; Pöllänen, Kati; Karjalainen, Milja; Rantanen, Jukka; Louhi-Kultanen, Marjatta; Nyström, Lars

    2005-02-01

    Currently there is a great interest in new process analytical approaches to increase the process understanding of pharmaceutical unit operations. In the present study, the influence of the solvent composition on the material properties and, further, on the filtration characteristics, of different crystal suspensions obtained through an unseeded batch-cooling-crystallization process was studied. Sulphathiazole, which is an antibiotic agent with multiple polymorphic forms, was produced by performing laboratory-scale cooling crystallization experiments from five different mixtures of water and propan-1-ol (n-propanol). The size, shape and polymorphic composition of the crystals produced were characterized with a scanning electron microscope, with a novel automated image analyser and with an X-ray powder diffractometer. All of the monitored crystal properties were found to clearly differ between the samples obtained from different solvents. The crystals produced in the batch-cooling-crystallization experiments were separated from the crystallizing solvents using a batch-type pressure Nutsche filter, and the filtration characteristics of the suspensions were evaluated on the basis of average filter-cake porosities and average specific cake resistances, which were determined from the experimentally obtained filtration data. Comparison between the calculated filtration characteristics revealed that considerable differences existed between the different suspensions, and it could therefore be concluded that the pressure-filtration process was influenced by the composition of the crystallizing solvent. The filterability of all the studied sulphathiazole suspensions was considered to be rather good on the basis of the relatively low cake porosities (0.51-0.63), which were accompanied with low average specific cake resistances [(8.7 x 10(7))-(1.2 x 10(9)) m/kg].

  12. Transparent phosphosilicate glasses containing crystals formed during cooling of melts

    DEFF Research Database (Denmark)

    Liu, S. J.; Zhang, Yanfei; He, W.;

    2011-01-01

    The effect of P2O5-SiO2 substitution on spontaneous crystallization of SiO2-Al2O3-P2O5- Na2O-MgO melts during cooling was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and rotation viscometry. Results show that addition of P2O5 lea...... Na2MgSiO4 is also enhanced during cooling of the melts. In addition, the sizes of the local crystalline and separated glassy domains are smaller than the wavelength of the visible light, and this leads to the transparency of the obtained glasses containing crystals....

  13. Transparent phosphosilicate glasses containing crystals formed during cooling of melts

    DEFF Research Database (Denmark)

    Liu, S. J.; Zhang, Yanfei; He, W.

    2011-01-01

    The effect of P2O5-SiO2 substitution on spontaneous crystallization of SiO2-Al2O3-P2O5- Na2O-MgO melts during cooling was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and rotation viscometry. Results show that addition of P2O5 leads...

  14. Crystallization Behavior and Growing Process of Rutile Crystals in Ti-Bearing Blast Furnace Slag

    Science.gov (United States)

    Zhang, Wu; Zhang, Li; Li, Yuhai; Li, Xin

    2016-09-01

    The aim of the present work is to elucidate crystallization and growing process of rutile crystals in Ti-bearing blast furnace slag. The samples were taken from the liquid slag and quenched at once at elevated temperatures in order to analyze phase transaction of titanium and grain size of rutile crystals. Crystallization and growing kinetics of rutile crystals under elevated temperature conditions were calculated, and the crystallization process of rutile crystals under isothermal conditions was expressed by Avrami equation. The effects of experimental parameters, such as experimental temperatures, SiO2 addition, cooling rate, crystal seed addition and oxygen flow, were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the optimal conditions for rutile crystals to grow up were obtained. Distribution and movement state of rutile crystals in the slag were analyzed.

  15. Control of heat transfer in continuous-feeding Czochralski-silicon crystal growth with a water-cooled jacket

    Science.gov (United States)

    Zhao, Wenhan; Liu, Lijun

    2017-01-01

    The continuous-feeding Czochralski method is an effective method to reduce the cost of single crystal silicon. By promoting the crystal growth rate, the cost can be reduced further. However, more latent heat will be released at the melt-crystal interface under a high crystal growth rate. In this study, a water-cooled jacket was applied to enhance the heat transfer at the melt-crystal interface. Quasi-steady-state numerical calculation was employed to investigate the impact of the water-cooled jacket on the heat transfer at the melt-crystal interface. Latent heat released during the crystal growth process at the melt-crystal interface and absorbed during feedstock melting at the feeding zone was modeled in the simulations. The results show that, by using the water-cooled jacket, heat transfer in the growing crystal is enhanced significantly. Melt-crystal interface deflection and thermal stress increase simultaneously due to the increase of radial temperature at the melt-crystal interface. With a modified heat shield design, heat transfer at the melt-crystal interface is well controlled. The crystal growth rate can be increased by 20%.

  16. Cryogenic cooling of x-ray crystals using porous matrix

    Energy Technology Data Exchange (ETDEWEB)

    Kuzay, T.M.

    1991-01-01

    It is well established that Si and SiC have very desirable thermophysical properties at cryogenic temperatures. This feature makes cryo-cooled optics potentially a good candidate for the first optical crystal of the presently built third generation synchrotron machines with very high heat flux levels. Currently, there is a great deal of interest in such cryo-cooled crystals pursued both experimentally and analytically. The analytical studies involve cut micro or capillary channel crystals. As opposed to the machined channels, porous matrices provide significant advantages. They operate very quietly. Such matrices are known to affect superior heat transfer enhancement. Data available in open literature suggest that surface heat flux levels up to {approximately}8 kW/cm{sup 2} are possible. For cryogens for which the boiling heat transfer heat flux is rather a low value in conventional geometries, the enhancement available with such matrices is a very significant characteristic. Cryogens are poor thermal conductors themselves. The fact that at the cryogenic temperatures the Si and/or SiC matrix itself becomes highly conductive, the matrix distributes the surface heat flux into the full volume effectively offsetting the poor conductivity of the coolant. In addition the tortuous path of the coolant through the matrix increases the dwell time for better heat transfer, however, at the expense of increased pressure drop. In this study, thermal conductivity of such composite matrices and the effective heat transfer coefficient obtainable using them are investigated. A first optics crystal model of Si with Si and/or Sic porous matrix as its heat exchanger and subject to prototype synchrotron level heat flux is analyzed and limits of the cooling possible with liquid nitrogen in single phase and subcooled boiling heat transfer modes are delineated.

  17. Process integration: Cooling water systems design

    CSIR Research Space (South Africa)

    Gololo, KV

    2010-10-01

    Full Text Available This paper presents a technique for grassroot design of cooling water system for wastewater minimization which incorporates the performances of the cooling towers involved. The study focuses mainly on cooling systems consisting of multiple cooling...

  18. Cooling water systems design using process integration

    CSIR Research Space (South Africa)

    Gololo, KV

    2010-09-01

    Full Text Available Cooling water systems are generally designed with a set of heat exchangers arranged in parallel. This arrangement results in higher cooling water flowrate and low cooling water return temperature thus reducing cooling tower efficiency. Previous...

  19. Polymorphic behavior of isonicotinamide in cooling crystallization from various solvents

    Science.gov (United States)

    Hansen, Thomas B.; Taris, Alessandra; Rong, Ben-Guang; Grosso, Massimiliano; Qu, Haiyan

    2016-09-01

    In this work the nucleation of different polymorphs of isonicotinamide (INA) from different solvents has been studied. The metastable zone width of INA in cooling crystallization from five different solvents has been investigated and attempts have been made to reveal the link between the INA molecular self-association to the polymorphism of the nucleated crystals using ATR FT-IR (Attenuated Total Reflectance Fourier Transform Infrared) and Raman spectroscopy. Raman and IR spectra of INA dissolved in different solvents have demonstrated that the INA molecules might associate in different configurations, whereas, the link between the structure of the molecular self-association and the structure of the nucleated polymorph is complicated by the influence of INA concentration. This is consistent with our previous study with piroxicam. The cooling crystallization of INA from five different solvents resulted in two different polymorphs depending on the initial concentration of the solution. The results obtained in the present work showed that information about self-association of an API (Active Pharmaceutical Ingredient) in a given solvent is not sufficient to predict the polymorphic behavior in all scenarios.

  20. Dissipation by a crystallization process

    Science.gov (United States)

    Dorosz, Sven; Voigtmann, Thomas; Schilling, Tanja

    2016-01-01

    We discuss crystallization as a non-equilibrium process. In a system of hard spheres under compression at a constant rate, we quantify the amount of heat that is dissipated during the crystallization process. We interpret the dissipation as arising from the resistance of the system against phase transformation. An intrinsic compression rate is identified that separates a quasi-static regime from one of rapidly driven crystallization. In the latter regime the system crystallizes more easily, because new relaxation channels are opened, at the cost of forming a higher fraction of non-equilibrium crystal structures. We rationalize the change in the crystallization mechanism by analogy with shear thinning, in terms of a kinetic competition between near-equilibrium relaxation and external driving.

  1. Systematic Procedure for Generating Operational Policies to Achieve Target Crystal Size Distribution (CSD) in Batch Cooling Crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    Batch cooling crystallization is one of the important unit operations involving separation of solid-liquid phases. Usually the most common crystal product qualities are directly related to the crystal size distribution (CSD). However the main difficulty in batch crystallization is to obtain a uni...

  2. Focused beam reflectance measurement as a tool for in situ monitoring of the lactose crystallization process

    National Research Council Canada - National Science Library

    Pandalaneni, K; Amamcharla, J K

    2016-01-01

    .... Production of lactose is usually carried out by a process called crystallization. Several factors including rate of cooling, presence of impurities, and mixing speed influence the crystal size characteristics...

  3. Crystallization and Cooling of a Deep Silicate Magma Ocean

    Science.gov (United States)

    Bower, Dan; Wolf, Aaron

    2016-04-01

    Impact and accretion simulations of terrestrial planet formation suggest that giant impacts are both common and expected to produce extensive melting. The moon-forming impact, for example, likely melted the majority of Earth's mantle to produce a global magma ocean that subsequently cooled and crystallised. Understanding the cooling process is critical to determining magma ocean lifetimes and recognising possible remnant signatures of the magma ocean in present-day mantle heterogeneities. Modelling this evolution is challenging, however, due to the vastly different timescales and lengthscales associated with turbulent convection (magma ocean) and viscous creep (present-day mantle), in addition to uncertainties in material properties and chemical partitioning. We consider a simplified spherically-symmetric (1-D) magma ocean to investigate both its evolving structure and cooling timescale. Extending the work of Abe (1993), mixing-length theory is employed to determine convective heat transport, producing a high resolution model that parameterises the ultra-thin boundary layer (few cms) at the surface of the magma ocean. The thermodynamics of mantle melting are represented using a pseudo-one-component model, which retains the simplicity of a standard one-component model while introducing a finite temperature interval for melting. This model is used to determine the cooling timescale for a variety of plausible thermodynamic models, with special emphasis on comparing the center-outwards vs bottom-up cooling scenarios that arise from the assumed EOS.

  4. Quartz Crystal Microbalance Technique for in Situ Analysis of Supersaturation in Cooling Crystallization.

    Science.gov (United States)

    Liu, Li-Shang; Kim, Jong-Min; Kim, Woo-Sik

    2016-06-07

    A quartz crystal microbalance (QCM) is used as a novel in situ strategy for analyzing the supersaturation profile during cooling crystallization. The main concept is based on preventing any solid mass loading on the QCM sensor by modifying the sensor surface. As a result, the QCM responses only depend on the solution concentration changes during the crystallization. The proposed strategy is confirmed on the basis of an analysis of sulfamerazine (SMZ) crystallization. When the QCM sensor is modified using 11-amino-1-undecanethiol (AUT), crystal formation on the sensor is completely prevented due to a repulsive interaction between the -NH2 functional groups of the AUT and SMZ crystals. Thus, the QCM responses reflect only the property changes in the solution phase during the crystallization. The supersaturation in the solution is then estimated on the basis of the difference in the frequency shifts between the SMZ solution and a blank solution. The accuracy of the in situ QCM analysis of supersaturation is confirmed using an off-line gravimetric method.

  5. Desalting a process cooling water using nanofiltration

    NARCIS (Netherlands)

    Radier, R.G.J.; van Oers, C.W.; Steenbergen, A.; Wessling, Matthias

    2001-01-01

    The cooling water system of a chemical plant of Akzo Nobel is a partly open system. The site is located at the North Sea. The air in contact with the cooling water contains seawater droplets dissolving and increasing the chloride concentration. The cooling water contains chromate to protect the inst

  6. Development of Cooling Process Control Technique in Hot Strip Mill

    Institute of Scientific and Technical Information of China (English)

    HAN Bin; LIU Xiang-hua; WANG Guo-dong; SHE Guang-fu

    2005-01-01

    In order to ensure required mechanical properties of steel strip, various innovations in the cooling process control on the run-out table of a hot strip mill were actively promoted. The recent progress of process mathematical model and the new cooling strategy and equipment were discussed. The computer control system of high performance was introduced. The development trend in cooling process control was given.

  7. Process for Encapsulating Protein Crystals

    Science.gov (United States)

    Morrison, Dennis R.; Mosier, Benjamin

    2003-01-01

    A process for growing protein crystals encapsulated within membranes has been invented. This process begins with the encapsulation of a nearly saturated aqueous protein solution inside semipermeable membranes to form microcapsules. The encapsulation is effected by use of special formulations of a dissolved protein and a surfactant in an aqueous first liquid phase, which is placed into contact with a second, immiscible liquid phase that contains one or more polymers that are insoluble in the first phase. The second phase becomes formed into the semipermeable membranes that surround microglobules of the first phase, thereby forming the microcapsules. Once formed, the microcapsules are then dehydrated osmotically by exposure to a concentrated salt or polymer solution. The dehydration forms supersaturated solutions inside the microcapsules, thereby enabling nucleation and growth of protein crystals inside the microcapsules. By suitable formulation of the polymer or salt solution and of other physical and chemical parameters, one can control the rate of transport of water out of the microcapsules through the membranes and thereby create physicochemical conditions that favor the growth, within each microcapsule, of one or a few large crystals suitable for analysis by x-ray diffraction. The membrane polymer can be formulated to consist of low-molecular-weight molecules that do not interfere with the x-ray diffraction analysis of the encapsulated crystals. During dehydration, an electrostatic field can be applied to exert additional control over the rate of dehydration. This protein-crystal-encapsulation process is expected to constitute the basis of protein-growth experiments to be performed on the space shuttle and the International Space Station. As envisioned, the experiments would involve the exposure of immiscible liquids to each other in sequences of steps under microgravitational conditions. The experiments are expected to contribute to knowledge of the precise

  8. Temperature field of steel plate cooling process after plate rolling

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Full Text Available Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

  9. Multivariant simulator for vacuum cooling processes of three component electrolyte systems

    Directory of Open Access Journals (Sweden)

    Suljkanović Midhat

    2010-01-01

    Full Text Available In this paper, a computer aided analysis and synthesis of the crystallization processes from multicomponent electrolyte systems were studied. In addition, the vacuum crystallization processes with adiabatic cooling of the system are presented. The cooling process of a multicomponent electrolyte system can be considered as a process with the concentration of the system and/or the crystallization of the solid phase from the system. Requirements for multivariant options of the process simulator are the result of practical needs in the design of new processes or the improvement of exploitation processes. According to this, there are needs for a simulation of a simple flashing of the system as well as for the vacuum cooling crystallization processes with the cyclic structure. The possibilities of the created process simulator are illustrated on three component electrolyte systems. Application of the process simulator for any other electrolyte systems requires only an update of the thermodynamic model, and physico-chemical properties related to electrolyte system.

  10. Systematic procedure for generating operational policies to achieve target crystal size distribution (CSD) in batch cooling crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    2011-01-01

    A systematic procedure to achieve a target crystal size distribution (CSD) under generated operational policies in batch cooling crystallization is presented. An analytical CSD estimator has been employed in the systematic procedure to generate the necessary operational policies to achieve the ta...

  11. Physical and Structural Studies on the Cryo-cooling of Insulin Crystals

    Science.gov (United States)

    Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

    2003-01-01

    Reflection profiles were analyzed from microgravity-(mg) and earth-grown insulin crystals to measure mosaicity (h) and to reveal mosaic domain structure and composition. The effects of cryocooling on single and multi-domain crystals were compared. The effects of cryocooling on insulin structure were also re-examined. Microgravity crystals were larger, more homogeneous, and more perfect than earth crystals. Several mg crystals contained primarily a single mosaic domain with havg of 0.005deg. The earth crystals varied in quality and all contained multiple domains with havg of 0.031deg. Cryocooling caused a 43-fold increase in h for mg crystals (havg=0.217deg) and an %fold increase for earth crystals (havg=0.246deg). These results indicate that very well-ordered crystals are not completely protected from the stresses associated with cryocooling, especially when structural perturbations occur. However, there were differences in the reflection profiles. For multi-mosaic domain crystals, each domain individually broadened and separated from the other domains upon cryo-cooling. Cryo-cooling did not cause an increase in the number of domains. A crystal composed of a single domain retained this domain structure and the reflection profiles simply broadened. Therefore, an improved signal-to-noise ratio for each reflection was measured from cryo-cooled single domain crystals relative to cryo-cooled multi-domain crystals. This improved signal, along with the increase in crystal size, facilitated the measurement of the weaker high- resolution reflections. The observed broadening of reflection profiles indicates increased variation in unit cell dimensions which may be linked to cryo-cooling-associated structural changes and disorder.

  12. On-line monitoring of the crystallization process: relationship between crystal size and electrical impedance spectra

    Science.gov (United States)

    Zhao, Yanlin; Yao, Jun; Wang, Mi

    2016-07-01

    On-line monitoring of crystal size in the crystallization process is crucial to many pharmaceutical and fine-chemical industrial applications. In this paper, a novel method is proposed for the on-line monitoring of the cooling crystallization process of L-glutamic acid (LGA) using electrical impedance spectroscopy (EIS). The EIS method can be used to monitor the growth of crystal particles relying on the presence of an electrical double layer on the charged particle surface and the polarization of double layer under the excitation of alternating electrical field. The electrical impedance spectra and crystal size were measured on-line simultaneously by an impedance analyzer and focused beam reflectance measurement (FBRM), respectively. The impedance spectra were analyzed using the equivalent circuit model and the equivalent circuit elements in the model can be obtained by fitting the experimental data. Two equivalent circuit elements, including capacitance (C 2) and resistance (R 2) from the dielectric polarization of the LGA solution and crystal particle/solution interface, are in relation with the crystal size. The mathematical relationship between the crystal size and the equivalent circuit elements can be obtained by a non-linear fitting method. The function can be used to predict the change of crystal size during the crystallization process.

  13. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian)

    OpenAIRE

    Daniela Ogrean

    2001-01-01

    The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes) indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Tim...

  14. Spray mist cooling heat transfer in glass tempering process

    Science.gov (United States)

    Sozbir, Nedim; Yao, S. C.

    2016-10-01

    Energy saving is a very important issue in glass plants, especially in a glass tempering process, where very high velocity air jet impingement is applied during the cooling process of glass tempering. In fact, air compressor energy may be reduced by a spray cooling due to its high heat transfer capabilities. Presently, in this paper, both pure air and water mist spray cooling are investigated in the glass tempering process. The test results indicate that thin and low-cost tempered glass can be made by mist cooling without fracture. It is possible to find the optimal water flux and duration of mist application to achieve a desirable temperature distribution in the glass for deep penetration of the cooling front but without inducing cracking during the tempering. The use of mist cooling could give about 29 % air pressure reduction for 2-mm glass plate and 50 % reduction for both 3- and 4-mm glass plates.

  15. Theory of vibrational cooling in molecular crystals: Application to crystalline naphthalene

    Science.gov (United States)

    Hill, Jeffrey R.; Dlott, Dana D.

    1988-07-01

    The process of vibrational cooling (VC) is theoretically investigated in the molecular crystal naphthalene. Specificially we consider the process where a highly excited vibration cools by emitting lower energy vibrations (vibrational relaxation, or VR) and phonons. We also consider the subsequent cooling of emitted optic phonons by emission of acoustic phonons. Using previously determined vibrational lifetimes [J. R. Hill et al., J. Chem. Phys. 88, 949 (1988)], a consistent transition rate matrix is obtained which describes VR of all vibrations and optic phonons at all temperatures. Then a Master equation is solved numerically to obtain the time dependent vibrational populations of all states following impulse excitation of a high frequency vibration. These results are compared to a previously derived analytic model for VC in molecular crystals [J. R. Hill and D. D. Dlott, J. Chem. Phys. 89, 830 (1988)]. In that theory, which is shown to be in good agreement with the naphthalene calculation, the excess vibrational excitation moves to lower energy states and broadens as time increases. The motion toward lower energy states is described by a temperature independent ``vibrational velocity'' (emitted energy per unit time). In naphthalene, the vibrational velocity is V0 ≊9 cm-1 /ps. The VC process occurs on a time scale as much as an order of magnitude longer than an individual VR step. Although VR is highly temperature dependent, VC is not. The VC calculations are used to predict the decay from the initial state, the time dependent populations of transient vibrational excitations, and the return to the vibrationless ground state. All these quantities are directly related to experimental observables such as incoherent anti-Stokes Raman scattering and hot luminescence.

  16. Detailed numerical simulations of laser cooling processes

    Science.gov (United States)

    Ramirez-Serrano, J.; Kohel, J.; Thompson, R.; Yu, N.

    2001-01-01

    We developed a detailed semiclassical numerical code of the forces applied on atoms in optical and magnetic fields to increase the understanding of the different roles that light, atomic collisions, background pressure, and number of particles play in experiments with laser cooled and trapped atoms.

  17. Composition dependence of spontaneous crystallization of phosphosilicate glass melts during cooling

    DEFF Research Database (Denmark)

    Liu, S.J.; Zhu, C.F.; Zhang, Y.F.

    2012-01-01

    Crystallization behavior of alumino-phospho-silicate melts during cooling is studied by means of the differential scanning calorimetry, X-ray diffractometry and viscometry. The results show a pronounced impact of alkaline earth oxide, alkali oxide and fluoride on the crystal type...

  18. Geometrical effect in magneto-Peltier cooling of single crystal Bi

    Science.gov (United States)

    Yamashita, Osamu; Satou, Kouji; Tomiyoshi, Shoichi

    2004-06-01

    The cooling temperatures of rectangular parallelepiped Bi single crystals with various widths W and thickness t were measured at 293 K as a function of electric current in the magnetic field B up to 2.17 T. The magnetic field was aligned along the thickness of a sample and the current flows along its length L through the copper leads soldered to both end surfaces of cross section (W×t), where W, t, and L are parallel to the binary, bisector, and trigonal axes of Bi single crystal, respectively. The thermoelement was not in contact with a heat sink. The cooling temperature at the cooled surface increased with increasing the magnetic field, and it depended strongly on the thickness rather than the width of the crystal in high magnetic fields. The largest maximum cooling temperature was achieved when a thermoelement has optimum dimensions so that no heat energy is generated at the cold side. The cooling temperature of Bi single crystal with optimum dimensions of L=15 mm, W=4 mm, and t=2 mm increased from 4.1 K in B=0 T to 8.5 K in B=+2.17 T, so that it exceeded maximum cooling temperatures of 5.7 K obtained for a typical Bi2Te3 and 5.2 K measured previously for a polycrystalline Bi in B=+2.17 T.

  19. Structural and phase transformations in iron-based alloy obtained in conditions of high cooling rate crystallization

    Science.gov (United States)

    Kovalevskaya, Zh. G.; Khimich, M. A.

    2016-11-01

    The production of parts by selective electron beam melting (SEBM) is accompanied by the formation of nonequilibrium structures. This is caused by the crystallization of alloys with high cooling rates. To evaluate the influence of cooling rate on the process of structural and phase transformations in the Fe-8Si-5Al-2C alloy, the electron beam melting of plasma coating was carried out. The dendritic structure was formed in the molten pool. The distance between dendritic branches of the second order was 2-5 µm. This corresponds to the cooling rate of about 103 K/s. The electron microscopy has shown that dendrites were formed by α-phase, while γ-phase was localized between α-phase crystals in form of intercalations. The secondary phases (intermetallic, aluminum and iron carbosilicides, aluminates and iron carboaluminates) are of sub-micron size and located in the α- and γ-phase boundary intersections or within the grains of the main phase. The microhardness of the alloy increases twofold. This suggests that complex hardening by solid-solution and dispersed hardening by the secondary phase particles occurs during crystallization with the above-mentioned cooling rate.

  20. A high-precision cryogenically-cooled crystal monochromator for the APS diagnostics beamline

    Energy Technology Data Exchange (ETDEWEB)

    Rotela, E.; Yang, B.; Sharma, s.; Barcikowski, A.

    2000-07-24

    A high-precision cryogenically-cooled crystal monochromator has been developed for the APS diagnostics beamline. The design permits simultaneous measurements of the particle beam size and divergence. It provides for a large rotation angle, {minus}15{degree} to 180{degree}, with a resolution of 0.0005{degree}. The roll angle of the crystal can be adjusted by up to {+-}3{degree} with a resolution of 0.0001{degree}. A vertical translational stage, with a stroke of {+-}25 mm and resolution of 8 {micro}m, is provided to enable using different parts of the same crystal or to retract the crystal from the beam path. The modular design will allow optimization of cooling schemes to minimize thermal distortions of the crystal under high heat loads.

  1. Cooling process of the LHC energy extraction resistors

    CERN Document Server

    Peón-Hernández, G; Coelingh, G J; CERN. Geneva. ST Division

    2003-01-01

    The energy stored in all the LHC dipoles, about 11 GJ, can potentially cause severe damage to the magnets, bus bars and current leads. In order to protect the superconducting elements after a resistive transition, the energy is dissipated into dump resistors switched in series with the magnet chains. This paper describes the cooling process of the resistors and explains the choice process for the main components of the cooling equipment.

  2. Nonlinear MIMO Control of a Continuous Cooling Crystallizer

    Directory of Open Access Journals (Sweden)

    Pedro Alberto Quintana-Hernández

    2012-01-01

    Full Text Available In this work, a feedback control algorithm was developed based on geometric control theory. A nonisothermal seeded continuous crystallizer model was used to test the algorithm. The control objectives were the stabilization of the third moment of the crystal size distribution (μ3 and the crystallizer temperature (T; the manipulated variables were the stirring rate and the coolant flow rate. The nonlinear control (NLC was tested at operating conditions established within the metastable zone. Step changes of magnitudes ±0.0015 and ±0.5°C were introduced into the set point values of the third moment and crystallizer temperature, respectively. In addition, a step change of ±1°C was introduced as a disturbance in the feeding temperature. Closed-loop stability was analyzed by calculating the eigenvalues of the internal dynamics. The system presented a stable dynamic behavior when the operation conditions maintain the crystallizer concentration within the metastable zone. Closed-loop simulations with the NLC were compared with simulations that used a classic PID controller. The PID controllers were tuned by minimizing the integral of the absolute value of the error (IAE criterion. The results showed that the NLC provided a suitable option for continuous crystallization control. For all analyzed cases, the IAEs obtained with NLC were smaller than those obtained with the PID controller.

  3. Numerical investigation into thermal effects of pre-cooling zone in vitrification-based cryopreservation process.

    Science.gov (United States)

    Tsai, Hsun-Heng; Tsai, Chien-Hsiung; Wu, Wei-Te; Chen, Fu-Zen; Chiang, Pei-Ju

    2015-02-01

    Most studies on ultra-fast cryopreservation assume an immediate placement of the cryopreservation tube in the liquid nitrogen tank. However, in practice, before the tube is placed into the liquid nitrogen, it passes through a space containing gaseous nitrogen (pre-cooling zone) formed via the evaporation of the bulk liquid nitrogen. Comparing with ultra-fast cryopreservation, the cooling rate is insufficiently high during the falling transition to vitrify the liquid. As the tube passes through this region, its temperature may fall to the temperature required for the formation of ice crystals, and thus cell damage may occur. Consequently, in optimizing the cryopreservation process, the effects of this transition region should be properly understood. Accordingly, the present study utilizes a thermal model to investigate the temperature variation in the tube as it falls through the pre-cooling region. The simulation results show that the cooling rate within the tube increases with an increasing tube velocity. Furthermore, the results reveal that the cooling rate at the front end of the tube is higher than that at any other position of the tube. Thus, to prevent the formation of ice crystals, the material used to seal the front end of the tube should have a low thermal conductivity. In addition, a streamlined design of the front end of the tube is advised. Finally, the cooling rate within the tube depends on the tube material as well as the falling speed. The height of the pre-cooling zone needs to be carefully designed based on the tube material and falling speed, thus the ice crystal formation can be prevented.

  4. Asymmetric crystallization upon heating and cooling in model glass-forming systems

    Science.gov (United States)

    Wang, Minglei; Zhang, Kai; Liu, Yanhui; Schroers, Jan; Shattuck, Mark; O'Hern, Corey

    2014-03-01

    We perform molecular dynamics simulations of binary Lennard-Jones (LJ) and hard-sphere (HS) systems to understand the asymmetry in the critical cooling and heating rates for crystallization observed in experiments on bulk metallic glasses, where much faster heating rates are required to prevent crystallization. For the LJ systems, we cool the systems at different rates (above the critical cooling rate Rc) to temperatures below the glass transition, and subsequently begin heating the samples at different rates to measure the critical heating rate Rh below which the system crystallizes. We perform companion studies of HS systems, except we measure the asymmetry in the critical compression and dilation rates to enhance the asymmetry. We show that the asymmetry increases with the glass-formability of the binary mixtures and explain this result by characterizing the structural order of the systems.

  5. Minimization of temperature for laser cooling of Yb-ion-doped crystals.

    Science.gov (United States)

    Ivanov, Andrei; Rozhdestvensky, Yuriy; Perlin, Evgeniy

    2016-10-01

    In this paper, quantum mechanical calculations of cooling characteristics for the Yb3+:  YLF system with use of the vibronic model of laser cooling are presented. Dynamics of the laser cooling process for the seven-level system of an Yb ion is described by the density-matrix formalism. Dependences of the cooling characteristics on the pump intensity are obtained for various temperatures and absorption coefficients of impurity ions. It is shown that the pump intensity, at which the net cooling power has a maximum, depends on temperature. Thus, choosing the intensities, which correspond to the net cooling power maximum over the entire temperature range, we achieve a lower sample temperature at a shorter time than in the case of using a constant intensity throughout the cooling process. Calculations are performed for the parameters of the Yb3+:YLF system.

  6. Influence of rare earth oxides on the non-isothermal crystallization of phosphosilicate melts during cooling

    DEFF Research Database (Denmark)

    Liu, S.J.; Shan, Z.T.; Fu, G.Z.;

    2014-01-01

    We report a detailed calorimetric study concerning the influence of Yb2O3 and Er2O3 on the non-isothermal crystallization in phosphosilicate melts. The results show that Yb3+/Er3+ ions promote the Zn2SiO4 crystal formation, but suppress the Na3PO4 and AlPO4 formation during cooling. The non......-isothermal melt-crystallization kinetics can be well described by the Avrami model. The activation energy Ee of crystallization in both the undoped and Yb3+/Er3+ codoped samples during cooling is determined using the differential iso-conversional method of Friedman. The Ee value decreases with crystallinity (θ...

  7. Cooling crystallization of Indomethacin from different organic solvents

    DEFF Research Database (Denmark)

    Malwade, Chandrakant Ramkrishna; Qu, Haiyan

    In the present work, crystallization of an anti-inflammatory drug Indomethacin (IMC) from different organic solvents was investigated concerning the polymorphism and particulate properties of the final product. Initially, the solvents were screened by measuring solubility of IMC at temperatures 1...

  8. Image processing of 2D crystal images.

    Science.gov (United States)

    Arheit, Marcel; Castaño-Díez, Daniel; Thierry, Raphaël; Gipson, Bryant R; Zeng, Xiangyan; Stahlberg, Henning

    2013-01-01

    Electron crystallography of membrane proteins uses cryo-transmission electron microscopy to image frozen-hydrated 2D crystals. The processing of recorded images exploits the periodic arrangement of the structures in the images to extract the amplitudes and phases of diffraction spots in Fourier space. However, image imperfections require a crystal unbending procedure to be applied to the image before evaluation in Fourier space. We here describe the process of 2D crystal image unbending, using the 2dx software system.

  9. A new crystallization process in polypropylene highly filled with calcium carbonate

    NARCIS (Netherlands)

    Schawe, Jurgen E.K.; Vermeulen, Paul A.; van Drongelen, Martin

    2015-01-01

    The influence of high amounts of calcium carbonate filler on the crystallization behavior of polypropylene (PP) is investigated by differential scanning calorimetry (DSC) and fast scanning DSC measurements. The non-isothermal crystallization process at industrially relevant cooling rates of about

  10. Kinetic crystallization separation process of the inositol isomers by controlling metastable zones

    Science.gov (United States)

    Konuki, Kaname; Hirasawa, Izumi

    2013-06-01

    D-chiro-inositol (DCI) is prepared by the immobilized enzyme reaction which uses myo-inositol (MI) as the substrate and the conversion rate is about 13%. The aim of this study was to develop a separation method for high purity DCI crystals from a reaction solution including low purity DCI only by the crystallization process. We succeeded in separating DCI crystals of 96% purity by water cooling crystallization, but it was presumed that scale-up was difficult. Although we tried anti-solvent crystallization similar to water cooling crystallization, high purity DCI crystals were not obtained. Therefore, we proposed the crystallization separation process by controlling metastable zones. The purity of a desired compound is controlled by this process, because solid-liquid separation is achieved before crystallization of compound in metastable zone. By the crystallization using this method, the DCI crystals of 97% purity were obtained. Although the yield per batch is about 50%, the actual yield is improved as the last mother liquor returns into the process of the following batch. When this process was repeated, the purity and the yield of DCI were reproduced and the robustness of this process was proved. It is expected that scale-up of this process will be successful, and this purification method could be applicable to similar systems such as separation of isomers and analogs.

  11. In situ thermal characterization of cooling/crystallizing lavas during rheology measurements and implications for lava flow emplacement

    Science.gov (United States)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2016-12-01

    Transport properties of natural silicate melts at super-liquidus temperatures are reasonably well understood. However, migration and transport of silicate melts in the Earth's crust and at its surface generally occur at sub-liquidus temperatures and in settings where the melts undergo crystallization under various cooling and/or decompression conditions. In such dynamic situations the occurrence of processes such as the release of latent heat during phase changes, viscous heating, thermal advection and -inertia, and changing heat capacity, all represent potential influences on the state, and thereby on the physico-chemical behavior of the system. To date, rheological data at sub-liquidus temperatures are scarce and cooling-rate dependent, disequilibrium rheological data are virtually absent. In fact, no in situ thermal characterization of liquid or multiphase mixtures during rheological experiments, under either static or dynamic thermal conditions has been presented to date. Here we describe a new experimental setup for in situ thermal characterization of cooling/crystallizing lavas during viscosity measurement at temperatures up to 1600 °C. We use this device to recover in situ, real-time, observations of the combined rheological and thermal evolution of natural, re-melted lava samples during the transient disequilibrium conditions characteristic of lava flows and shallow crustal magma migration and storage systems in nature. We present the calibration procedure and the method employed to recover the thermal evolution of an experimental sample during flow in varying shear regimes, assess the experimental uncertainty and show the ability of the apparatus to measure the release of latent heat of crystallization during transient rheological experiments. We further report the results from a first experimental study on the rheological and thermal evolution of a basaltic lava undergoing continuous cooling at a series of different cooling rates and discuss the

  12. Cooling system optimization analysis for hot forming processes

    Science.gov (United States)

    Ghoo, Bonyoung; Umezu, Yasuyoshi; Watanabe, Yuko

    2013-12-01

    Hot forming technology was developed to produce automotive panels having ultra-high tensile stress over 1500MPa. The elevated temperature corresponds with decreased flow stress and increased ductility. Furthermore, hot forming products have almost zero springback amounts. This advanced forming technology accelerates the needs for numerical simulations coupling with thermal-mechanical formulations. In the present study, 3-dimensional finite element analyses for hot forming processes are conducted using JSTAMP/NV and LS-DYNA considering cooling system. Special attention is paid to the optimization of cooling system using thermo-mechanical finite element analysis through the influence of various cooling parameters. The presented work shows an adequate cooling system functions and microstructural phase transformation material model together with a proper set of numerical parameters can give both efficient and accurate design insight in hot forming manufacturing process. JSTAMP/NV and LS-DYNA can become a robust combination set for complex hot forming analysis which needs thermo-mechanical and microstructural material modeling and various process modeling. The use of the new JSTAMP/NV function for multishot manufacturing process is shown good capabilities in cooling system evaluation. And the use of the advanced LS-DYNA microstructural phase transformation model is shown good evaluation results in martensite amount and Vickers hardness after quenching.

  13. Forward to cryogenic temperature: laser cooling of Yb: LuLiF crystal

    Science.gov (United States)

    Zhong, Biao; Luo, Hao; Lei, Yongqing; Shi, Yanling; Yin, Jianping

    2017-06-01

    The high quality Yb-doped fluoride crystals have broad prospects for optical refrigeration. We have laser cooled the Yb:LuLiF crystal to a temperature below the limit of current thermoelectric coolers ( 180 K). The 5% Yb:LuLiF crystal sample has a geometry of 2 mm×2 mm×5 mm and was supported by two fibers of 200 μm in diameter. They were placed in a 2×10-4 Pa vacuum chamber with an environment temperature of 294.5 K. The 1019 nm CW laser of power 38.7 W was adopted to irradiate the sample. The temperature of the sample was measured utilizing the DLT methods. After 20 minutes of laser irradiation, the 5% Yb:LuLiF crystal sample was cooled down to 182.4 K. By further optimizing experimental conditions and increasing the doped Yb concentration, the Yb:LuLiF crystal might be optically cooled below the cryogenic temperature of 123K in the near future.

  14. γ-CuI crystal growth in ionic liquids by the oxygen-free cooling method

    Science.gov (United States)

    Lou, Bingqian; Zhang, Jingfu; Luo, Hong; Pan, Jingen; Pan, Jianguo

    2014-02-01

    A novel method is applied to grow γ-CuI crystal by the oxygen-free cooling method with solvent of [BMIm]Br. The solubility curve of CuI solution of [BMIm]Br at different temperatures is measured by means of the improved weight analysis. The γ-CuI single crystals with dimensions of 10×7×2 mm3 are obtained. The growth temperature is from 170 °C to 120 °C. Stirring speed is 60 r/min. Cooling rate is 1.5-2 °C/d. The effect of oxygen on the stability of solution has been studied by UV-vis spectra and XRD. The γ-CuI crystals are characterized by X-ray powder diffraction and differential thermal analysis/thermogravimetry.

  15. Enhanced electrocaloric cooling in ferroelectric single crystals by electric field reversal

    Science.gov (United States)

    Ma, Yang-Bin; Novak, Nikola; Koruza, Jurij; Yang, Tongqing; Albe, Karsten; Xu, Bai-Xiang

    2016-09-01

    An improved thermodynamic cycle is validated in ferroelectric single crystals, where the cooling effect of an electrocaloric refrigerant is enhanced by applying a reversed electric field. In contrast to the conventional adiabatic heating or cooling by on-off cycles of the external electric field, applying a reversed field is significantly improving the cooling efficiency, since the variation in configurational entropy is increased. By comparing results from computer simulations using Monte Carlo algorithms and experiments using direct electrocaloric measurements, we show that the electrocaloric cooling efficiency can be enhanced by more than 20% in standard ferroelectrics and also relaxor ferroelectrics, like Pb (Mg1 /3 /Nb2 /3)0.71Ti0.29O3 .

  16. Baryon direct Urca processes in neutron star cooling

    CERN Document Server

    Xu, Yan; Fan, Cun Bo; Zhang, Xiao Jun; Bao, Tmurbagan; Zhu, Ming Feng; Wang, Hong Yan

    2015-01-01

    A detailed description of the nucleon direct Urca processes related to the neutron star cooling is given and how they are affected by the degrees of freedom of hyperons and hyperon direct Urca processes are presented. These results indicate that the appearance of hyperons can sharply suppress the neutrino emissivity of the nucleon direct Urca processes.However, the contribution of the reactions $\\Lambda\\rightarrow p+e+\\bar{\

  17. Integration of Generic Multi-dimensional Model and Operational Policies for Batch Cooling Crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    Crystallization processes form an important class of separation methods that are frequently used in the chemical, the pharmaceutical and the food industry. The specifications of the crystal product are usually given in terms of crystal size, shape and purity. In order to predict the desired cryst...

  18. A study on controlled cooling process for making bainitic ductile iron

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    In the present research, TTT curve of bainitic ductile iron under the condition of controlled cooling was generated. The cooling rate of grinding ball and its temperature distribution were also measured at the same time. It can be concluded that the bainitic zone of TTT curve is separated from the pearlitic zone. As compared to the water-quenching condition, more even cooling rate and temperature distribution can be achieved in the controlled cooling process. The controlled cooling can keep away from pearlitic zone in the high temperature cooling stage and produce similar results to the process of traditional isothermal cooling with a low cooling rate in the low temperature cooling stage.

  19. Cooling rates and crystallization dynamics of shallow level pegmatite-aplite dikes, San Diego County, California

    Science.gov (United States)

    Webber, Karen L.; Simmons, William B.; Falster, Alexander U.; Foord, Eugene E.

    1999-01-01

    Pegmatites of the Pala and Mesa Grande Pegmatite Districts, San Diego County, California are typically thin, sheet-like composite pegmatite-aplite dikes. Aplitic portions of many dikes display pronounced mineralogical layering referred to as "line rock," characterized by fine-grained, garnet-rich bands alternating with albite- and quartz-rich bands. Thermal modeling was performed for four dikes in San Diego County including the 1 m thick Himalaya dike, the 2 m thick Mission dike, the 8 m thick George Ashley dike, and the 25 m thick Stewart dike. Calculations were based on conductive cooling equations accounting for latent heat of crystallization, a melt emplacement temperature of 650 °C into 150 °C fractured, gabbroic country rock at a depth of 5 km, and an estimated 3 wt% initial H2O content in the melt. Cooling to -5 cm/s. Crystal size distribution (CSD) studies of garnet from layered aplites suggest growth rates of about 10-6 cm/s. These results indicate that the dikes cooled and crystallized rapidly, with variable nucleation rates but high overall crystal-growth rates. Initial high nucleation rates coincident with emplacement and strong undercooling can account for the millimeter-size aplite grains. Lower nucleation rates coupled with high growth rates can explain the decimeter-size minerals in the hanging walls, cores, and miarolitic cavities of the pegmatites. The presence of tourmaline and/or lepidolite throughout these dikes suggests that although the melts were initially H2O-undersaturated, high melt concentrations of incompatible (or fluxing) components such as B, F, and Li (±H2O), aided in the development of large pegmatitic crystals that grew rapidly in the short times suggested by the conductive cooling models.

  20. An Experimental Study on Constraint Cooling Process of Hot-rolled CoilS

    Institute of Scientific and Technical Information of China (English)

    Lijuan WANG; Chunli ZHANG

    2003-01-01

    In order to master mechanical property, surface quality and microstructure of constraint cooling (CC) coils undervarious water cooling parameters, more than 100 coils cooling experiments were done with real production process,of which is designed a coolin

  1. Transport Processes in Dendritic Crystallization

    Science.gov (United States)

    Glicksman, M. E.

    1984-01-01

    Free dentritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical dendrite problem. The development of theoretical understanding of dendritic growth and its experimental status is sketched showing that transport theory and interfacial thermodynamics (capillarity theory) are insufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of maximum velocity was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to be able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip.

  2. On the Lower Limit of Chondrule Cooling Rates: The Significance of Iron Loss in Dynamic Crystallization Experiments

    Science.gov (United States)

    Paque, Julie M.; Connolly, Harold C., Jr.; Lofgren, Gary E.

    1998-01-01

    It is unlikely that the presence of chondrules, and thus their formation, within the protoplanetary nebula would be predicted if it were not for their ubiquitous presence in most chondritic meteorites. The study of these enigmatic, igneous objects has a direct influence on how meteoritic and solar system researchers model the processes operating and the materials present within our protoplanetary nebula. Key to understanding chondrule formation is a determination of constraints on their thermal histories. The three important variables in this history are their peak melting temperatures, the duration of their melting at peak temperatures, and the rate at which these object cool. Although these three variables are interdependent, it is cooling rate that provides the most powerful constraint. Cooling rate has a direct affect on the development of both crystal morphology and the elemental distributions within these grains. To date, experiments have indicated that chondrule cooling rates are in the range of 10's to 100's of degrees per hour for porphyritic chondrules (the most abundant type). The cooling rate for radial and barred chondrules is thought to be more rapid. To generate these cooling rates (rapid relative to the cooling of the nebula as a whole, but slow compared to simple black body radiation) the environment of chondrule formation must have been localized, and the abundance of solid materials must have been greatly enhanced above a gas of solar composition. Thus accurate determinations of chondrule cooling rates is critical in understanding both their formation and the nebular environment in which they formed. In a quest to more accurately determine the lower limit on cooling rates and to determine in more detail the effects of Fe loss from a molten sample to Pt wire loops, Weinbruch et al. have explored this issue experimentally and reevaluated the findings of Radomsky and Hewins in light of their new results. The basic conclusions of their paper are an

  3. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian

    Directory of Open Access Journals (Sweden)

    Daniela Ogrean

    2001-04-01

    Full Text Available The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district and between 539–958 respectively, in case of the Racoş basalts (Braşov district. There is a certain variation of the hardness within the same sample, in various measurement points, within the theoretical limits of the hardnesses of the pyroxenes and that of the spinels.

  4. Improved Large-Scale Process Cooling Operation through Energy Optimization

    Directory of Open Access Journals (Sweden)

    Kriti Kapoor

    2013-11-01

    Full Text Available This paper presents a study based on real plant data collected from chiller plants at the University of Texas at Austin. It highlights the advantages of operating the cooling processes based on an optimal strategy. A multi-component model is developed for the entire cooling process network. The model is used to formulate and solve a multi-period optimal chiller loading problem, posed as a mixed-integer nonlinear programming (MINLP problem. The results showed that an average energy savings of 8.57% could be achieved using optimal chiller loading as compared to the historical energy consumption data from the plant. The scope of the optimization problem was expanded by including a chilled water thermal storage in the cooling system. The effect of optimal thermal energy storage operation on the net electric power consumption by the cooling system was studied. The results include a hypothetical scenario where the campus purchases electricity at wholesale market prices and an optimal hour-by-hour operating strategy is computed to use the thermal energy storage tank.

  5. Engineered Cooling Process for High Strength Ductile Iron Castings

    Science.gov (United States)

    Lekakh, Simon N.; Mikhailov, Anthony; Kramer, Joseph

    Professor Stefanescu contributed fundamentally to the science of solidification and microstructural evolutions in ductile irons. In this article, the possibility of development of high strength ductile iron by applying an engineered cooling process after casting early shake out from the sand mold was explored. The structures in industrial ductile iron were experimentally simulated using a computer controlled heating/cooling device. CFD modeling was used for process simulation and an experimental bench scale system was developed. The process concept was experimentally verified by producing cast plates with 25 mm wall thickness. The tensile strength was increased from 550 MPa to 1000 MPa in as-cast condition without the need for alloying and heat treatment. The possible practical applications were discussed.

  6. Estimate of influence of U-Th-K radiogenic heat on cooling process of granitic melt and its geological implications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The U-Th-40K concentrations of granite are on 1―2 orders of magnitude greater than those of basal- tic-ultrabasic rocks. Radiogenic heat of a granitic melt has significant influence on the cool- ing-crystallization period of the melt. In this paper we derived a formula to calculate prolongation period (tA) of cooling-crystallization of a granitic melt caused by radiogenic heat. Calculation using this for- mula and radioactive element concentrations (U=5.31×10-6; Th=23.1×10-6; K=4.55%) for the biotite adamellite of the Jinjiling batholith shows that the tA of the adamellite is 1.4 times of the cooling period of the granitic melt without considering radiogenic heat from the initial temperature (Tm=960℃) to crystallization temperature (Tc=600℃) of the melt. It has been demonstrated that the radiogenic heat produced in a granitic melt is a key factor influencing the cooling-crystallization process of the granitic melt, and is likely one of the reasons for inconsistence between emplacement ages and crystallization ages of many Meso-Cenozoic granitoids.

  7. Multi-dimensional population balance models of crystallization processes

    DEFF Research Database (Denmark)

    Meisler, Kresten Troelstrup; von Solms, Nicolas

    A generic and model-based framework for batch cooling crystallization operations has been extended to incorporate continuous and fed-batch processes. Modules for the framework have been developed, including a module for reactions, allowing the study of reactive crystallization within the framework...... and parameters for the simulation can be found in the database. A procedure for parameter estimation has been illustrated based on experimental work. The identifiability of the models has been discussed in relation to parameter estimation using sensitivity analysis. Some important identifiability issues have...... been investigated using the model structure to simulate perfect data and data with white noise added to it. It is found that the kinetic models may not be reliably estimated from the concentration profile using the parameter estimation procedure for both perfect and noisy data. The framework has been...

  8. Simulation and optimization of fractional crystallization processes

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter; Gani, Rafiqul

    1998-01-01

    A general method for the calculation of various types of phase diagrams for aqueous electrolyte mixtures is outlined. It is shown how the thermodynamic equilibrium precipitation process can be used to satisfy the operational needs of industrial crystallizer/centrifuge units. Examples of simulation...... and optimization of fractional crystallization processes are shown. In one of these examples, a process with multiple steady states is analyzed. The thermodynamic model applied for describing the highly non-ideal aqueous electrolyte systems is the Extended UNIQUAC model. (C) 1998 Published by Elsevier Science Ltd...

  9. Crystallization and cooling conditions for diogenite formation in the turbulent magma ocean of asteroid 4 Vesta

    Science.gov (United States)

    Kawabata, Yusuke; Nagahara, Hiroko

    2017-01-01

    Despite its small size, the asteroid 4 Vesta has been completely differentiated to core and mantle. Its composition is similar to howardite-eucrite-diogenite (HED) meteorites of which the detailed petrology is known. Therefore, 4 Vesta is a good target for understanding the differentiation of terrestrial planets. A new differentiation model for crust formation has been developed by taking magma ocean fluid dynamics, chemical equilibrium, the presence of 26Al, and cooling into consideration with a special focus on crystal separation. The role of crystal size, thickness of the conductive lid, and fO2 are evaluated as parameters. The results show that large crystals of at least 1 cm settled and formed a kilometer-thick cumulate layer of orthopyroxene with Mg # of 0.70-0.90 in ∼20 thousand years, which almost agrees with the Mg # of diogenites. Smaller grain sizes formed thinner layers.

  10. Effect of high-intensity ultrasound and cooling rate on the crystallization behavior of beeswax in edible oils.

    Science.gov (United States)

    Jana, Sarbojeet; Martini, Silvana

    2014-10-15

    The objective of this study was to evaluate the effect of wax concentration (0.5 and 1%), cooling rate (0.1, 1, and 10 °C/min), and high-intensity ultrasound (HIU) on the crystallization behavior of beeswax (BW) in six different edible oils. Samples were crystallized at 25 °C with and without HIU. Crystal sizes and morphologies and melting profiles were measured by microscopy and differential scanning calorimetry, respectively, after 7 days of incubation. Higher wax concentrations resulted in faster crystallization and more turbidity. Phase separation was observed due to crystals' sedimentation when samples were crystallized at slow cooling rates. Results showed that HIU induced the crystallization of 0.5% BW samples and delayed phase separation in sunflower, olive, soybean, and corn oils. Similar effects were observed in 1% samples where HIU delayed phase separation in canola, soybean, olive, and safflower oils.

  11. Residual thermal stress of a mounted KDP crystal after cooling and its effects on second harmonic generation of a high-average-power laser

    Science.gov (United States)

    Su, Ruifeng; Liu, Haitao; Liang, Yingchun; Yu, Fuli

    2017-01-01

    Thermal problems are huge challenges for solid state lasers that are interested in high output power, cooling of the nonlinear optics is insufficient to completely solve the problem of thermally induced stress, as residual thermal stress remains after cooling, which is first proposed, to the best of our knowledge. In this paper a comprehensive model incorporating principles of thermodynamics, mechanics and optics is proposed, and it is used to study the residual thermal stress of a mounted KDP crystal after cooling process from mechanical perspective, along with the effects of the residual thermal stress on the second harmonic generation (SHG) efficiency of a high-average-power laser. Effects of the structural parameters of the mounting configuration of the KDP crystal on the residual thermal stress are characterized, as well as the SHG efficiency. The numerical results demonstrate the feasibility of solving the problems of residual thermal stress from the perspective on structural design of mounting configuration.

  12. Study the effect of cryogenic cooling on orthogonal machining Process

    Directory of Open Access Journals (Sweden)

    Arvind Kaushal

    2016-06-01

    Full Text Available In present scenario , all the manufacturing organization aims to maximize the productivity of organization in respect of all the aspect of manufacturing process, in case of machining process, it associated with various factors which affect the productivity directly in sense of tool life . Temperature, cutting forces, shear angle, work-piece surface finishing & accuracy, amount of power consumed in machining process and other thing also. All the factors might be optimized by applying effective and efficient amount of coolant throughout the process, to get desired efficiency of process. A coolant play a vital role in machining operation but which must have specific properties which have been reviewed in previous article of various student , research scholars , scientist and industrial candidates .in this research paper , we were focusing on the effect of cryogenic cooling on cutting temperature , cutting forces , chip behavior , shear angle , when alloy steel EN-8 and aluminum alloy 6061-T89 was machined by carbide cutting tool (coated & uncoated & applying liquid nitrogen as a coolant and observed that temperature was decreased during the machining process about 16% to 27% and cutting forces improved to 13%when the machining was performed , the same without cooling of EN-8 alloy, similarly on the other hand in case of aluminum alloy 6061-T89 , temperature was decreased to 25% to 37% and cutting force improved to 9% .

  13. Slurry and processing technique of CLBO crystal

    Institute of Scientific and Technical Information of China (English)

    WANG Sheng-li; LIU Yu-ling; NIU Xin-huan; TAN Bai-mei

    2006-01-01

    CsLiB6O10(CLBO) is a new-type nonlinear optical crystal material. CLBO has many good performances,especially the frequency multiplication performance in deep ultraviolet band. CLBO has important application prospect on solid-state UV laser,broad band tunable laser and laser nucleus flame igniter. Though,CLBO will be air slaking and cracking when the ambient humidity is more than 40%,which brings more difficult on CLBO surface finishing. According to the performance and structure characteristic of CLBO crystal,a new water-free slurry applying for CLBO crystal chemical mechanical polishing(CMP) was investigated. The abrasive is SiO2. The influence of polishing processing parameter on polishing process for CLBO crystal was discussed,and the parameter optimal value of polishing plate speed,pressure,pH value and abrasive concentration were determined. Through such parameters,high efficiency and precision plane polishing was gotten. The CLBO CMP process was studied,the results show that low pressure and high speed can improve the CLBO crystal surface removal rate and flatness.

  14. Radiation processes in crystal solid solutions

    CERN Document Server

    Gladyshev, Gennadi

    2012-01-01

    This is a monograph explaining processes occurring in two classes of crystal solids (metal alloys and doped alkali halide) under irradiation by various types of radiation (alpha, beta, gamma, X-radiations, ions). This e-book is a useful reference for advanced readers interested in the physics of radiation and solid state physics.

  15. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    Science.gov (United States)

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-06

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  16. Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

    Science.gov (United States)

    Dubost, B.; Dubessy, R.; Szymanski, B.; Guibal, S.; Likforman, J.-P.; Guidoni, L.

    2014-03-01

    We measured by laser spectroscopy the isotope shifts between naturally occurring even isotopes of strontium ions for both the 5s2S1/2→5p2P1/2 (violet) and the 4d2D3/2→5p2P1/2 (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing 103-104 laser-cooled Sr+ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom interacting with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the 5s2S1/2→5p2P1/2 transition are ν88-ν84=+378(4) MHz and ν88-ν86=+170(3) MHz, in agreement with previously reported measurements. In the case of the previously unexplored 4d2D3/2→5p2P1/2 transition we find ν88-ν84=-828(4) MHz and ν88-ν86=-402(2) MHz. These results provide more data for stringent tests of theoretical calculations of the isotope shifts of alkali-metal-like atoms. Moreover, they simplify the identification and the addressing of Sr+ isotopes for ion frequency standards or quantum-information-processing applications in the case of multi-isotope ion strings.

  17. Performance of Cooled Cone Grinding Machine in Cocoa Cake Processing

    Directory of Open Access Journals (Sweden)

    Hendy Firmanto

    2015-08-01

    Full Text Available The process of cocoa paste pressing has a function to separate the fatty component of cocoa from its cake. Cocoa paste is further processed into cocoa powder using grinding machine for cocoa cake. The cooled cone type of cocoa grinding machine is used to solve the problem of plug in the maschine caused by melting of fat in cocoa cake due to hot effect as a result of friction in the grinding machine. Grinding machine of cocoa has conical form of cylinder for grinding and stator wall wrapped by source of cold and closed with jacket wool. Research was conducted at Kaliwining Experimental Garden of Indonesian Coffee and Cocoa Research Institute (ICCRI using cocoa cake containing 26.75% originated from Forastero type of cocoa seed. The capacity and recovery of the machine was influenced by space between rotor cylinder and stator wall. Grinding machine operated at cooling temperature of 25.5oC and space between rotor – stator 0.9 cm and the capacity of 187.5 kg/hour with recovery of 200 mesh cocoa powder as much as 24%. The maximum  power of machine required  was 2.5 kW with efficiency of  energy transfer of 97%. Results of proximate analysis showed that there was no change of protein content, but protein and carbohydrate content increased after processing, i.e. from 5.70% and 59.82% into 5.80% and 61.89% respectively.Key words : cocoa cake, cooling, grinding, cocoa powder 

  18. Designing Robust Process Analytical Technology (PAT) Systems for Crystallization Processes: A Potassium Dichromate Crystallization Case Study

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan

    2013-01-01

    The objective of this study is to test and validate a Process Analytical Technology (PAT) system design on a potassium dichromate crystallization process in the presence of input uncertainties using uncertainty and sensitivity analysis. To this end a systematic framework for managing uncertainties...... in the nucleation and crystal growth parameters affect the product-process performances (e.g. crystal size distribution (CSD)). Analysis of the proposed PAT system design (closedloop), on the other hand, shows that the effect of the input uncertainties on the outputs (product quality) is minimized, and the target...

  19. Landauer's blowtorch effect as a thermodynamic cross process: Brownian cooling

    Science.gov (United States)

    Das, Moupriya; Das, Debojyoti; Barik, Debashis; Ray, Deb Shankar

    2015-11-01

    The local heating of a selected region in a double-well potential alters the relative stability of the two wells and gives rise to an enhancement of population transfer to the cold well. We show that this Landauer's blowtorch effect may be considered in the spirit of a thermodynamic cross process linearly connecting the flux of particles and the thermodynamic force associated with the temperature difference and consequently ensuring the existence of a reverse cross effect. This reverse effect is realized by directing the thermalized particles in a double-well potential by application of an external bias from one well to the other, which suffers cooling.

  20. The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

    OpenAIRE

    2008-01-01

    The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

  1. The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2008-08-01

    Full Text Available The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

  2. Laser-cooled atoms inside a hollow-core photonic-crystal fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Peyronel, Thibault

    2011-01-01

    We describe the loading of laser-cooled rubidium atoms into a single-mode hollow-core photonic-crystal fiber. Inside the fiber, the atoms are confined by a far-detuned optical trap and probed by a weak resonant beam. We describe different loading methods and compare their trade-offs in terms...... of implementation complexity and atom-loading efficiency. The most efficient procedure results in loading of ∼30,000 rubidium atoms, which creates a medium with an optical depth of ∼180 inside the fiber. Compared to our earlier study this represents a sixfold increase in the maximum achieved optical depth...

  3. Model of Flux Trapping in Cooling Down Process

    CERN Document Server

    Kubo, Takayuki

    2015-01-01

    The flux trapping that occurs in the process of cooling down of the superconducting cavity is studied. The critical fields $B_{c2}$ and $B_{c1}$ depend on a position when a material temperature is not uniform. In a region with $T\\simeq T_c$, $B_{c2}$ and $B_{c1}$ are strongly suppressed and can be smaller than the ambient magnetic field, $B_a$. A region with $B_{c2}\\le B_a$ is normal conducting, that with $B_{c1}\\le B_a B_a$ is in the Meissner state. As a material is cooled down, these three domains including the vortex state domain sweep and pass through the material. In this process, vortices contained in the vortex state domain are trapped by pinning centers distributing in the material. A number of trapped fluxes can be evaluated by using the analogy with the beam-target collision event, where beams and a target correspond to pinning centers and the vortex state domain, respectively. We find a number of trapped fluxes and thus the residual resistance are proportional to the ambient magnetic field and the...

  4. An experimental study of pyroxene crystallization during rapid cooling in a thermal gradient; applications to komatiites and chondrites

    Directory of Open Access Journals (Sweden)

    S. Bouquain

    2013-03-01

    Full Text Available To investigate the crystallization of pyroxene in spinifex-textured komatiites and in chondrites we undertook a series of experiments in which compositions in the CMAS system were cooling rapidly in a thermal gradient. Cooling rates were generally between 5 to 10 °C h−1 but some runs were made at 100–200 °C h−1; thermal gradients were between 10 and 20 °C cm−1. These conditions reproduced those at various levels in the crust of komatiitic lava flow. The starting composition was chosen to have pigeonite on the liquidus and a majority of the experiments crystallized zoned pigeonite-diopside crystals like those in komatiite lavas. A~conspicuous aspect of the experimental results was their lack of reproduceability. Some experiments crystallized forsterite whereas others that were run under similar conditions crystallized two pyroxenes and no forsterite; some experiments were totally glassy but others totally crystallized to pyroxene. The degree of supercooling at the onset of pyroxene crystallization was variable, from less than 25 °C to more than 110 °C. We attribute these results to the difficulty of nucleation of pyroxene. In some cases forsterite crystallized metastably and modified the liquid composition to inhibit pyroxene crystallization; in others no nucleation took place until a large degree of supercooling was achieved, then pyroxene crystallized rapidly. Pigeonite crystallized under a wide range of conditions, at cooling rates from 3 to 100 °C h−1. The notion that this mineral only forms at low cooling rates is not correct.

  5. Effect of cooling rate on the crystallization behavior of perovskite in high titanium-bearing blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    Lu Liu; Mei-long Hu; Chen-guang Bai; Xue-weiLü; Yu-zhou Xu; Qing-yu Deng

    2014-01-01

    The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace (BF) slag was studied using confocal scanning laser microscopy (CSLM). Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the ortho-rhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attrib-uted to the deficiency of O2-,when Ti2O3 was involved in the formation of perovskite.

  6. Additional force field in cooling process of cellular Al alloy

    Institute of Scientific and Technical Information of China (English)

    郑明军; 何德坪; 戴戈

    2002-01-01

    The foaming process of Al alloy is similar to that of Al, but there is a solid-liquid state zone in the solidification process of cellular Al alloy which does not exist in the case of Al. In the unidirectional solidification of cellular Al alloy, the proportion of the solid phase gradually reduces from the solid front to the liquid front. This will introduce a force and result in a serious quick shrinkage. By the mathematic and physical mode, the solidification of the cellular Al alloy is studied. The data measured by experiment are close to the result calculated by the mode. This kind of shrinkage can be solved by suitable cooling method in appropriate growth stage. The compressive strength of the cellular Al alloy made by this way is 40% higher than that of cellular Al.

  7. Atomic collision processes for modelling cool star spectra

    Science.gov (United States)

    Barklem, Paul

    2015-05-01

    The abundances of chemical elements in cool stars are very important in many problems in modern astrophysics. They provide unique insight into the chemical and dynamical evolution of the Galaxy, stellar processes such as mixing and gravitational settling, the Sun and its place in the Galaxy, and planet formation, to name a just few examples. Modern telescopes and spectrographs measure stellar spectral lines with precision of order 1 per cent, and planned surveys will provide such spectra for millions of stars. However, systematic errors in the interpretation of observed spectral lines leads to abundances with uncertainties greater than 20 per cent. Greater precision in the interpreted abundances should reasonably be expected to lead to significant discoveries, and improvements in atomic data used in stellar atmosphere models play a key role in achieving such advances in precision. In particular, departures from the classical assumption of local thermodynamic equilibrium (LTE) represent a significant uncertainty in the modelling of stellar spectra and thus derived chemical abundances. Non-LTE modelling requires large amounts of radiative and collisional data for the atomic species of interest. I will focus on inelastic collision processes due to electron and hydrogen atom impacts, the important perturbers in cool stars, and the progress that has been made. I will discuss the impact on non-LTE modelling, and what the modelling tells us about the types of collision processes that are important and the accuracy required. More specifically, processes of fundamentally quantum mechanical nature such as spin-changing collisions and charge transfer have been found to be very important in the non-LTE modelling of spectral lines of lithium, oxygen, sodium and magnesium.

  8. Processing-structure-mechanical property relationship in Ti-Nb microalloyed steel: Continuous cooling versus interrupted cooling

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, V.V. [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Liu, S. [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Challa, V.S.A. [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Misra, R.D.K., E-mail: dmisra2@utep.edu [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Sidorenko, D.M.; Mulholland, M.D.; Manohar, M.; Hartmann, J.E. [ArcelorMittal Global R& D Center, 3001 East Columbus Drive, East Chicago, IN 46312 (United States)

    2016-08-01

    The process parameters associated with thermo-mechanical controlled processing (TMCP) of steels play an important role in influencing the ultimate mechanical properties. The study of TMCP parameters have not received the required attention. In this regard, we elucidate here the impact of finish cooling temperature on interrupted cooling and compare with continuous cooling on microstructural evolution and precipitation behavior and associated mechanical properties in Ti-Nb microalloyed steels. The microstructural evolution was studied via transmission electron microscopy and electron back scattered diffraction (EBSD). The microstructure of continuously cooled and interrupted cooled steels with different finish exit temperatures consisted of polygonal ferrite, bainite and martensite/austenite constituent. However, the fraction of different microstructural constituents was different in each of the experimental steels. Similarly, there were differences in the distribution and average size of (Nb, Ti)C precipitates. The aforementioned differences in the microstructure and precipitation introduced differences in tensile properties. Furthermore, electron back scattered diffraction studies indicated distinct variation in average grain area and high angle boundaries between continuously cooled and interrupted cooled steels.

  9. EIS study on corrosion and scale processes and their inhibition in cooling system media

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Cruz, J. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico) and Instituto Mexicano del Petroleo, Coordinacion de Ingenieria Molecular, Competencia de Quimica Aplicada, Eje Central Lazaro Cardenas No. 152, CP 07730, DF (Mexico)]. E-mail: jmarin@imp.mx; Cabrera-Sierra, R. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico); Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE-IPN), Departamento de Metalurgia, UPALM Zacatenco AP 75-874, CP 07338, DF (Mexico); Pech-Canul, M.A. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios, Avanzados del IPN, AP 73 Cordemex, CP 97310, Merida, Yucatan (Mexico); Gonzalez, I. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico)]. E-mail: igm@xanum.uam.mx

    2006-01-20

    A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media.

  10. Effects of formulation and process factors on the crystal structure of freeze-dried Myo-inositol.

    Science.gov (United States)

    Izutsu, Ken-Ichi; Yomota, Chikako; Okuda, Haruhiro; Kawanishi, Toru; Yamaki, Takuya; Ohdate, Ryohei; Yu, Zhaokun; Yonemochi, Etsuo; Terada, Katsuhide

    2014-08-01

    The objective of this study was to elucidate effects of formulation and process variables on the physical forms of freeze-dried myo-inositol. Physical properties of myo-inositol in frozen solutions, freeze-dried solids, and cooled heat-melt solids were characterized by powder X-ray diffraction (PXRD), thermal analysis (differential scanning calorimetry [DSC] and thermogravimetric), and simultaneous PXRD-DSC analysis. Cooling of heat-melt myo-inositol produced two forms of metastable anhydrate crystals that change to stable form (melting point 225 °C-228 °C) with transition exotherms at around 123 °C and 181 °C, respectively. Freeze-drying of single-solute aqueous myo-inositol solutions after rapid cooling induced crystallization of myo-inositol as metastable anhydrate (transition at 80 °C-125 °C) during secondary drying segment. Contrarily, postfreeze heat treatment (i.e., annealing) induced crystallization of myo-inositol dihydrate. Removal of the crystallization water during the secondary drying produced the stable-form myo-inositol anhydrate crystal. Shelf-ramp slow cooling of myo-inositol solutions resulted in the stable and metastable anhydrous crystal solids depending on the solute concentrations and the solution volumes. Colyophilization with phosphate buffer retained myo-inositol in the amorphous state. Crystallization in different process segments varies crystal form of freeze-dried myo-inositol solids.

  11. Cooling of Ethanol Fermentation Process Using Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Sergio Colle

    2010-09-01

    Full Text Available

    Ethanol fermentation is an exothermic process, where the kinetics depends on temperature. This study proposes an alternative cooling system for use in ethanol fermentation using a single-eect water/lithium bromide absorption chiller, powered by waste heat from sugar and ethanol production processes, with a temperature range of 80 to 100 oC. The aim of this study is to model, simulate and analyze the behavior of an absorption refrigeration machine, according to the required cooling capacity of the fermentation system. A comparative analysis with and without the chiller is performed. The introduction of a chiller allowed a reduction in the temperature of the medium of around 1 oC and an increase of around 0.8 % in the fermentation efficiency. Under these conditions less cellular stress occurs and cellular viability is kept at higher levels. The results show that this reduction in temperature can increase the ethanol content of the wine. In the recovery of ethanol, a lower thermal load will be needed at the distillation, with a smaller amount of vinasse produced and consequently the energy efficiency of the plant will increase.

  12. Designing Robust Process Analytical Technology (PAT) Systems for Crystallization Processes: A Potassium Dichromate Crystallization Case Study

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan

    2013-01-01

    The objective of this study is to test and validate a Process Analytical Technology (PAT) system design on a potassium dichromate crystallization process in the presence of input uncertainties using uncertainty and sensitivity analysis. To this end a systematic framework for managing uncertaintie...

  13. Application of Microstructure Engineering in Steel Coil Cooling Process

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng-dong; D Q Jin; I V Samarasekera; J K Brimacombe

    2005-01-01

    The coil cooling and its role in a hot strip mill were reviewed.A mathematical model was developed to describe and analyze the thermal history and its impact on precipitation phenomena during coil cooling for plain car bon,HSLA-V and HSLA-Nb steels.The predicted result of the thermal model was compared with that measured from industrial coil.The effect of cooling condition and coil dimension on the thermal history and final mechanical properties of the steel strip was examined.The coiling temperature and cooling rate have crucial influence on the precipitation strengthening.

  14. An experimental comparison between a novel and a conventional cooling system for the blown film process

    Science.gov (United States)

    Janas, M.; Andretzky, M.; Neubert, B.; Kracht, F.; Wortberg, J.

    2016-03-01

    The blown film extrusion is a significant manufacturing process of plastic films. Compared to other extrusion processes, the productivity is limited by the cooling of the extrudate. A conventional cooling system for the blown film application provides the cooling air tangentially, homogeneous over the whole circumference of the bubble, using a single or dual lip cooling ring. In prior works, major effects could be identified that are responsible for a bad heat transfer. Besides the formation of a boundary sublayer on the film surface due to the fast flowing cooling air, there is the interaction between the cooling jet and the ambient air. In order to intensify the cooling of a tubular film, a new cooling approach was developed, called Multi-Jet. This system guides the air vertically on the film surface, using several slit nozzles over the whole tube formation zone. Hence, the jets penetrate the sublayer. To avoid the interaction with the ambient air, the bubble expansion zone is surrounded by a housing. By means of a numeric investigation, the novel cooling approach and the efficiency of the cooling system could be proved. Thereby, a four times higher local heat transfer coefficient is achieved compared to a conventional cooling device. In this paper, the Multi-Jet cooling system is experimentally tested for several different process conditions. To identify a worth considering cooling configuration of the novel cooling system for the experiment, a simulation tool presets the optimal process parameters. The comparison between the results of the new and a conventional system shows that the novel cooling method is able to gain the same frost line height using a 40% lower cooling air volume flow. Due to the housing of the tube formation zone, a heat recovery can be achieved.

  15. Focused beam reflectance measurement as a tool for in situ monitoring of the lactose crystallization process.

    Science.gov (United States)

    Pandalaneni, K; Amamcharla, J K

    2016-07-01

    Lactose accounts for about 75 and 85% of the solids in whey and deproteinized whey, respectively. Production of lactose is usually carried out by a process called crystallization. Several factors including rate of cooling, presence of impurities, and mixing speed influence the crystal size characteristics. To optimize the lactose crystallization process parameters to maximize the lactose yield, it is important to monitor the crystallization process. However, efficient in situ tools to implement at concentrations relevant to the dairy industry are lacking. The objective of the present work was to use a focused beam reflectance measurement (FBRM) system for in situ monitoring of lactose crystallization at supersaturated concentrations (wt/wt) 50, 55, and 60% at 20 and 30°C. The FBRM data were compared with Brix readings collected using a refractometer during isothermal crystallization. Chord length distributions obtained from FBRM in the ranges of crystals) and 50 to 300 µm (coarse crystals) were recorded and evaluated in relation to the extent of crystallization and rate constants deduced from the refractometer measurements. Extent of crystallization and rate constants increased with increasing supersaturation concentration and temperature. The measured fine crystal counts from FBRM increased at higher supersaturated concentration and temperature during isothermal crystallization. On the other hand, coarse counts were observed to increase with decreasing supersaturated concentration and temperature. Square weighted chord length distribution obtained from FBRM showed that as concentration increased, a decrease in chord lengths occurred at 20°C and similar observations were made from microscopic images. The robustness of FBRM in understanding isothermal lactose crystallization at various concentrations and temperatures was successfully assessed in the study. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Comparison of entropy difference in the cooling process

    Directory of Open Access Journals (Sweden)

    Ríos Cruellas G.

    2013-06-01

    Full Text Available The aim of this study is to create an overview of the various cooling technologies at room temperature. The energy absorbed during the cooling step is validated through an entropy analysis. The comparison involves vaporization, desorption of H2 of metal hydrides, isothermal expansion, magnetocaloric effect and chemical reaction.

  17. Cooling and crystallization of rhyolite-obsidian lava: Insights from micron-scale projections on plagioclase microlites

    Science.gov (United States)

    Sano, Kyohei; Toramaru, Atsushi

    2017-07-01

    To reveal the cooling process of a rhyolite-obsidian flow, we studied the morphology of plagioclase microlites in the Tokachi-Ishizawa lava of Shirataki, northern Hokkaido, Japan, where the structure of the lava can be observed from obsidian at the base of the flow to the innermost rhyolite. Needle-like micron-scale textures, known as ;projections;, occur on the short side surfaces of the plagioclase microlites. Using FE-SEM we discovered a positive correlation between the lengths and spacings of these projections. On the basis of the instability theory of an interface between melt and crystal, and to understand the length and spacing data, we developed a model that explains the positive correlation and allows us to simultaneously estimate growth rates and growth times. Applying the model to our morphological data and the estimated growth rates and growth times, we suggest that the characteristics of the projections reflect the degree of undercooling, which in turn correlates with lava structure (the obsidian at the margin of the flow experienced a higher degree of undercooling than the interior rhyolite). The newly developed method provides insights into the degree of undercooling during the final stages of crystallization of a rhyolitic lava flow.

  18. Control of cooling processes with forced-air aimed at efficiency energetic and the cooling time of horticultural products

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Carlos Teles Ribeiro da; Mederos, Barbara Janet Teruel [Universidade Estadual de Campinas (FEAGRI/UNICAMP), SP (Brazil). Fac. de Engenharia Agricola

    2008-07-01

    The application of cooling technologies for the conservation of horticultural products is one of the stages the Cold Chain. In Brazil particularly, as a country with tropical climate with average high temperature almost all year, the application of these technologies is very important because the shelf-life of fresh horticultural products, with quality that the market demands, is directly related to temperature. In particular, the systems of forced air cooling operate according to the flow of air predetermined in the project according to the quantity of product to cool. When actual conditions differ from considerations of the project, as to the quantity of product, a situation very common in agricultural properties and packing houses, the fan will continue providing the nominal flow rate, causing alteration of the cost-benefit relation of process. This project aims at the development of a micro-processing equipment (output current of 4 to 20 mA) to control the rotational speed of the motor of the fan systems, air forced through an inverter of frequency. The objective is development of a Man-Machine Interface, based on an algorithm, which, through the introduction of mass product data and the automatic acquisition of data from temperature of the product and the camera, is calculated the cooling time. The rotation of the engine fan will be amended automatically, to maintain air flow with a proper cost-benefit, in connection with the reduction of cooling time, energy consumption, for the increasing the shelf life of products. (author)

  19. Control of cooling processes with forced-air aimed at efficiency energetic and the cooling time of horticultural products

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Carlos Teles Ribeiro da; Mederos, Barbara Janet Teruel [Universidade Estadual de Campinas (FEAGRI/UNICAMP), SP (Brazil). Fac. de Engenharia Agricola

    2008-07-01

    The application of cooling technologies for the conservation of horticultural products is one of the stages the Cold Chain. In Brazil particularly, as a country with tropical climate with average high temperature almost all year, the application of these technologies is very important because the shelf-life of fresh horticultural products, with quality that the market demands, is directly related to temperature. In particular, the systems of forced air cooling operate according to the flow of air predetermined in the project according to the quantity of product to cool. When actual conditions differ from considerations of the project, as to the quantity of product, a situation very common in agricultural properties and packing houses, the fan will continue providing the nominal flow rate, causing alteration of the cost-benefit relation of process. This project aims at the development of a micro-processing equipment (output current of 4 to 20 mA) to control the rotational speed of the motor of the fan systems, air forced through an inverter of frequency. The objective is development of a Man-Machine Interface, based on an algorithm, which, through the introduction of mass product data and the automatic acquisition of data from temperature of the product and the camera, is calculated the cooling time. The rotation of the engine fan will be amended automatically, to maintain air flow with a proper cost-benefit, in connection with the reduction of cooling time, energy consumption, for the increasing the shelf life of products. (author)

  20. A layered cooling process in whole quenching process for lightweight front axle beam

    Directory of Open Access Journals (Sweden)

    Gao Kai

    2015-01-01

    Full Text Available In order to improve the uniformity of martensite distribution and obtain consistent mechanical performance during the quenching process of front axle beam, a layered cooling process was presented in this paper. The fluid-solid coupled temperature field were investigated by finite element modeling and the prediction of micro-structure and hardness distributions were also carried out. The experimental result verifies the reliability of this model.

  1. Effects of cooling interval and MnO2, TiO2, CdO, NiO additions on spheluritic willemite crystals

    Science.gov (United States)

    Coşkun, Nihal Derin; Uz, Veli; Issi, Ali; Genç, Soner; Çakı, Münevver

    2017-01-01

    Macro crystal production in crystal glaze systems is a very important topic in ceramic art and science. In this study, crystal growth was obtained in two different firing regimes. Recipes were prepared by adding MnO, TiO, NiO and CdO into the frit. The first firing regime, which is used in artistic ceramics, has a 100 °C cooling temperature interval. The second regime that has a 580 °C cooling temperature interval, was determined by DTA analysis. Then, the development of crystals was compared between these two firing regimes. According to the results, spheluritic willemite crystals up to three cm in the glazes doped MnO2 have been obtained by cooling it in a wide cooling interval. Larger willemite crystals were not formed in the narrow cooling temperature interval. It was determined that larger crystals can be produced by cooling at wide cooling temperature intervals and holding at lower temperature which involves nucleating the temperature of the crystal.

  2. A Comparative Study on Dissolution Enhancement of Acetaminophen by Cooling, Anti-solvent, and Solvent Evaporation Crystallization.

    Science.gov (United States)

    Chen, Ruilian; Wang, Xiaona; Liu, Wenli; Zhang, Kaixuan; Li, Yao; Wei, Zhenping

    2017-01-01

    The aim of this study was to prepare APAP crystals by cooling, anti-solvent, and solvent evaporation crystallization to enhance its dissolution rate and to make comparisons of the three methods. Agitating speeds and types were regarded as factors affecting crystallization procedure. Samples were made with different ratios of PEG4000. They were characterized by X-ray diffraction and scanning electron microscopy. Dissolution tests were conducted to assess their dissolution property. The proportions of carriers existing in crystals by cooling and anti-solvent crystallization ranged from 1.3 to 5.1%. Mean dissolution time (MDT) of samples by the two methods was about 3 min, which was 17.2 min for untreated APAP. Addition of too much PEG4000 in solvent evaporation crystallization could decrease dissolution rate of APAP. Samples agitated by a rotor with speed of 100, 500, and 1000 rpm dissolved faster than those by a high shear mixer with speed of 3400 and 5000 rpm or by a glass rod. Agitating speed and type could affect particle size and drug dissolution. Dissolution enhancement of APAP might be attributed to decrease of fine particles and increase of particle wettability.

  3. Systematic Modelling and Crystal Size Distribution Control for Batch Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    Crystallization processes form an important class of separation methods that are frequently used in the chemical, the pharmaceutical and the food industry. The specifications of the crystal product are usually given in terms of crystal size, shape and purity. In order to predict the desired cryst...

  4. Purification of precursors of Yb3+-doped YLF crystals by solvent extraction and electrochemical processing

    Science.gov (United States)

    Boncher, William L.; Judge, Elizabeth; Sansinena, Jose-Maria; Dirmyer, Matthew R.; Hehlen, Markus P.

    2015-03-01

    Optical refrigeration by laser irradiation of YLiF4:Yb3+ (YLF:Yb) crystals has been shown to be strongly deteriorated by impurities, which absorb energy at the laser wavelength, and relax non-radiatively, negating cooling produced from anti-Stokes fluorescence. We aim to increase the efficiency of optical refrigeration through materials purification. We start with the purest sources commercially available and process them in a cleanroom environment. Our method proceeds through electrochemical purification, separating out the transition metal impurities by their redox potentials, and can be scaled up to produce the amounts of material needed for crystal growth.

  5. Study on buoyancy convection phenomenon in the crystal growth process

    Institute of Scientific and Technical Information of China (English)

    DUAN Li; KANG Qi

    2009-01-01

    Real-time phase shift Mach-Zehnder interference technique,imaging technique,and computer image processing technique were combined to perform a real-time diagnosis of NaCIO3 crystal,which described both the dissolution process end the crystallization process of the NaCIO3 crystal in real-time condition.The dissolution fringes and the growth fringes in the process were obtained.Moreover,a distribution of concentration field in this process was obtained by inversion calculation.Finally,the buoyancy convection phenomenon caused by gravity in the crystal growth process was analyzed.The results showed that this convection phenomenon directly influences the growth rate of each crystal face in the crystal.

  6. Study on buoyancy convection phenomenon in the crystal growth process

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Real-time phase shift Mach-Zehnder interference technique, imaging technique, and computer image processing technique were combined to perform a real-time diagnosis of NaClO3 crystal, which de- scribed both the dissolution process and the crystallization process of the NaClO3 crystal in real-time condition. The dissolution fringes and the growth fringes in the process were obtained. Moreover, a distribution of concentration field in this process was obtained by inversion calculation. Finally, the buoyancy convection phenomenon caused by gravity in the crystal growth process was analyzed. The results showed that this convection phenomenon directly influences the growth rate of each crystal face in the crystal.

  7. Inhibition of calcium carbonate crystal growth by organic additives using the constant composition method in conditions of recirculating cooling circuits

    Science.gov (United States)

    Chhim, Norinda; Kharbachi, Chams; Neveux, Thibaut; Bouteleux, Céline; Teychené, Sébastien; Biscans, Béatrice

    2017-08-01

    The cooling circuits used in power plants are subject to mineral crystallization which can cause scaling on the surfaces of equipment and construction materials reducing their heat exchange efficiency. Precipitated calcium carbonate is the predominant mineral scale commonly observed in cooling systems. Supersaturation is the key parameter controlling the nucleation and growth of calcite in these systems. The present work focuses on the precipitation of calcite using the constant composition method at constant supersaturation, through controlled addition of reactants to a semi-batch crystallizer, in order to maintain constant solution pH. The determination of the thermodynamic driving force (supersaturation) was based on the relevant chemical equilibria, total alkalinity and calculation of the activity coefficients. Calcite crystallization rates were derived from the experiments performed at supersaturation levels similar to those found in industrial station cooling circuits. Several types of seeds particles were added into the aqueous solution to mimic natural river water conditions in terms of suspended particulate matters content, typically: calcite, silica or illite particles. The effect of citric and copolycarboxylic additive inhibitors added to the aqueous solution was studied. The calcium carbonate growth rate was reduced by 38.6% in the presence of the citric additive and a reduction of 92.7% was observed when the copolycarboxylic additive was used under identical experimental conditions. These results are explained by the location of the adsorbed inhibitor at the crystal surface and by the degree of chemical bonding to the surface.

  8. Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

    CERN Document Server

    Dubost, Brice; Szymanski, Benjamin; Guibal, Samuel; Likforman, Jean-Pierre; Guidoni, Luca

    2014-01-01

    We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ (violet) and the $4d\\,\\,^2D_{3/2}\\to 5p\\,\\,^2P_{1/2}$ (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing $10^3$--$10^4$ laser-cooled Sr$^+$ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom in interaction with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ transition are $\

  9. Group IVA irons: New constraints on the crystallization and cooling history of an asteroidal core with a complex history

    Science.gov (United States)

    McCoy, T. J.; Walker, R. J.; Goldstein, J. I.; Yang, J.; McDonough, W. F.; Rumble, D.; Chabot, N. L.; Ash, R. D.; Corrigan, C. M.; Michael, J. R.; Kotula, P. G.

    2011-11-01

    We report analyses of 14 group IVA iron meteorites, and the ungrouped but possibly related, Elephant Moraine (EET) 83230, for siderophile elements by laser ablation ICP-MS and isotope dilution. EET was also analyzed for oxygen isotopic composition and metallographic structure, and Fuzzy Creek, currently the IVA with the highest Ni concentration, was analyzed for metallographic structure. Highly siderophile elements (HSE) Re, Os and Ir concentrations vary by nearly three orders of magnitude over the entire range of IVA irons, while Ru, Pt and Pd vary by less than factors of five. Chondrite normalized abundances of HSE form nested patterns consistent with progressive crystal-liquid fractionation. Attempts to collectively model the HSE abundances resulting from fractional crystallization achieved best results for 3 wt.% S, compared to 0.5 or 9 wt.% S. Consistent with prior studies, concentrations of HSE and other refractory siderophile elements estimated for the bulk IVA core and its parent body are in generally chondritic proportions. Projected abundances of Pd and Au, relative to more refractory HSE, are slightly elevated and modestly differ from L/LL chondrites, which some have linked with group IVA, based on oxygen isotope similarities. Abundance trends for the moderately volatile and siderophile element Ga cannot be adequately modeled for any S concentration, the cause of which remains enigmatic. Further, concentrations of some moderately volatile and siderophile elements indicate marked, progressive depletions in the IVA system. However, if the IVA core began crystallization with ˜3 wt.% S, depletions of more volatile elements cannot be explained as a result of prior volatilization/condensation processes. The initial IVA core had an approximately chondritic Ni/Co ratio, but a fractionated Fe/Ni ratio of ˜10, indicates an Fe-depleted core. This composition is most easily accounted for by assuming that the surrounding silicate shell was enriched in iron

  10. Adaptation of in-situ microscopy for crystallization processes

    Science.gov (United States)

    Bluma, A.; Höpfner, T.; Rudolph, G.; Lindner, P.; Beutel, S.; Hitzmann, B.; Scheper, T.

    2009-08-01

    In biotechnological and pharmaceutical engineering, the study of crystallization processes gains importance. An efficient analytical inline sensor could help to improve the knowledge about these processes in order to increase efficiency and yields. The in-situ microscope (ISM) is an optical sensor developed for the monitoring of bioprocesses. A new application for this sensor is the monitoring in downstream processes, e.g. the crystallization of proteins and other organic compounds. This contribution shows new aspects of using in-situ microscopy to monitor crystallization processes. Crystals of different chemical compounds were precipitated from supersaturated solutions and the crystal growth was monitored. Exemplified morphological properties and different forms of crystals could be distinguished on the basis of offline experiments. For inline monitoring of crystallization processes, a special 0.5 L stirred tank reactor was developed and equipped with the in-situ microscope. This reactor was utilized to carry out batch experiments for crystallizations of O-acetylsalicyclic acid (ASS) and hen egg white lysozyme (HEWL). During the whole crystallization process, the in-situ microscope system acquired images directly from the crystallization broth. For the data evaluation, an image analysis algorithm was developed and implemented in the microscope analysis software.

  11. The effect of Pglass state on the non-isothermal cold and melt crystallization processes of PET matrix

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huichao [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Ma, Jinghong, E-mail: mjh68@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Gong, Jinghua [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Xu, Jian, E-mail: jxu@iccas.ac.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Beijing National Laboratory for Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-08-10

    Highlights: • Pglass is an inorganic polymer with low T{sub g} and mutable viscosity. • Kinetics models and activation energy can be used to analyze the process. • Pglass can play different effect on the crystallization process of PET. - Abstract: The physical state of phosphate glass (Pglass) has an influence on the non-isothermal crystallization behaviors of PET matrix in the PET/Pglass blends, which has been investigated via heating the glassy state and cooling the melt state of the blends at various scanning rates, respectively, by means of differential scanning calorimetry (DSC) technique. The kinetics models based on the Avrami and Mo equations were used to analyze the non-isothermal crystallization process. Furthermore, the activation energy of non-isothermal crystallization, according to Kissinger theory for heating process and Friedman theory for cooling process, has been evaluated. The results showed that the Pglass accelerated the non-isothermal cold crystallization rate of PET matrix due to its nucleation effect. In contrast, for the non-isothermal melt crystallization, the Pglass hindered the crystallization process due to its large melt viscosity.

  12. Crystallization processes derived from the interaction of urine and dolostone

    Science.gov (United States)

    Cámara, Beatriz; Alvarez de Buergo, Monica; Fort, Rafael

    2015-04-01

    The increase in the number of pets (mostly dogs), homeless people and the more recent open-air drinking sessions organized by young people in historical centers of European cities, derive on the augmentation of urinations on stone façades of the built cultural heritage. Up to now this process has been considered only under an undesirable aesthetical point of view and the insalubrious conditions it creates, together with the cleaning costs that the local governments have to assume. This study aims to confirm urine as a real source of soluble salts that can trigger the decay of building materials, especially of those of built cultural heritage of the historical centers of the cities, which are suffering the new social scenario described above. For this purpose, an experimental setup was designed and performed in the laboratory to simulate this process. 5 cm side cubic specimens of dolostone were subjected to 100 testing cycles of urine absorption by capillarity. The necessary amount of urine was collected by donors and stored following clinical protocol conditions. Each cycle consisted of imbibitions of the specimens in 3 mm high urine sheet for 3 hours, drying at 40°C in an oven for 20 hours and 1 hour cooling in a dessicator. At the end of the 100 cycles, small pieces of the specimens were cut, observed and analyzed with the aid of an environmental scanning electron microscope, which presents the advantage of no sample preparation. The sampled pieces were selected considering there were different sections in height in the specimens: a) a bottom section that corresponds to the section that has been immersed in the urine solution (3 mm); b) an interface section, immediately above the immersed area, which is the area most affected by the urine capillarity process, characterized by a strong yellowish color; c) the section that we have named as section of influence, which is subjected to the capillary absorption, although not so strongly than the interface section

  13. Evaluation of Process Cooling in Subsea Separation, Boosting and Injection Systems (SSBI)

    OpenAIRE

    Gyllenhammar, Svenn Emil

    2012-01-01

    The next generation of subsea process systems will combine the subsea gas compression technology currently under qualification with the previously developed subsea processing technologies, including separation, multiphase pumping and produced water re-injection. These systems will benefit from process cooling. This paper is an evaluation of the use of process cooling in subsea separation, boosting and injection (SSBI) systems including compression. Fouling is the biggest uncertainty, and pote...

  14. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  15. The effect of primary copper slag cooling rate on the copper valorization in the flotation process

    Directory of Open Access Journals (Sweden)

    Aleksandar Mihajlović

    2015-06-01

    Full Text Available Technological procedure of slow cooling slag from primary copper production is applied in the purpose of copper recovery in the level of 98.5% to blister. This technological procedure is divided into two phases, first slow cooling of slag on the air for 24 hours, and then accelerated cooling with water for 48 hours. Within the research following methods were used: calculation of nonstationary slag cooling, verification of the calculation using computer simulation of slag cooling in the software package COMSOL Multiphysics and experimental verification of simulation results. After testing of the experimentally gained samples of slowly cooled slag it was found that this technological procedure gives the best results in promoting growth or coagulation of dispersed particles of copper sulfide and copper in the slag, thereby increasing the utilization of the flotation process with a decrease of copper losses through very fine particles.

  16. Mechanism and simulation of external cooling in aluminum casting-rolling process

    Institute of Scientific and Technical Information of China (English)

    GAO Zhi

    2005-01-01

    External cooling technology is one of the key technologies to realize fast-casting-rolling process of aluminum, i.e. using compulsive cooling on the external surface of rollers and aluminum plate to improve the cooling ability of system, increase casting-rolling speed, and enhance the quality of aluminum plate. Heat transfer model of casting-rolling process was proposed and the characteristics of the temperature field of roller-plate system were analyzed. The influences of external cooling surface of the plate and the roller on the temperature field of the roller and the aluminum plate and the casting-rolling speed were discussed, and the relationship between external cooling and internal cooling were also analyzed. Experiment results show that, with the increase of casting-rolling speed, the influence of cooling plate surface on increasing casting-rolling speed was gradually decreased, but that of cooling roller surface was enhanced. Different mechanisms of external cooling plate surface and roller surface for improving casting-rolling speed account for this phenomenon.

  17. Thermodynamic equilibrium, metastable zone widths, and nucleation behavior in the cooling crystallization of gestodene-ethanol systems

    Science.gov (United States)

    Wang, Li-yu; Zhu, Liang; Yang, Li-bin; Wang, Yan-fei; Sha, Zuo-liang; Zhao, Xiao-yu

    2016-03-01

    A systematic investigation of nucleation behavior for the batch cooling crystallization of unseeded gestodene-ethanol solutions was carried out. The solubilities of the two polymorphs (forms I and II) of gestodene in ethanol were gravimetrically measured between 268.15 and 333.15 K under atmospheric pressure of 0.10 MPa. In addition, the metastable zone widths (MSZWs) of the gestodene-ethanol solutions were determined by the polythermal method combined with the focused beam reflectance measurement (FBRM®) technique. Moreover, polymorphic forms of the grown crystals were identified by X-ray powder diffraction (XRD) and optical microscope. Experimental results indicated that the measured MSZWs were dependent on numerous technological parameters, including cooling rate, saturation temperature, and agitation intensity. With variation of the nucleation temperature and cooling rate, forms I, II, and a mixture of the two forms were crystallized from ethanol solution. The nucleation kinetic parameters were estimated from MSZW data using the self-consistent Nývlt-like approach. Due to the high solubility of form I in ethanol at the corresponding temperature range, the stronger solute-solvent interactions confirmed that the nucleation of form I had a greater activation energy than that of form II.

  18. Recent Developments in the Crystallization Process: Toward the Pharmaceutical Industry

    Directory of Open Access Journals (Sweden)

    Zhenguo Gao

    2017-06-01

    Full Text Available Crystallization is one of the oldest separation and purification unit operations, and has recently contributed to significant improvements in producing higher-value products with specific properties and in building efficient manufacturing processes. In this paper, we review recent developments in crystal engineering and crystallization process design and control in the pharmaceutical industry. We systematically summarize recent methods for understanding and developing new types of crystals such as co-crystals, polymorphs, and solvates, and include several milestones such as the launch of the first co-crystal drug, Entresto (Novartis, and the continuous manufacture of Orkambi (Vertex. Conventional batch and continuous processes, which are becoming increasingly mature, are being coupled with various control strategies and the recently developed crystallizers are thus adapting to the needs of the pharmaceutical industry. The development of crystallization process design and control has led to the appearance of several new and innovative crystallizer geometries for continuous operation and improved performance. This paper also reviews major recent progress in the area of process analytical technology.

  19. The crystallization processes in the aluminum particles production technology

    Directory of Open Access Journals (Sweden)

    Arkhipov Vladimir

    2015-01-01

    Full Text Available The physical and mathematical model of the crystallization process of liquid aluminum particles in the spray-jet of the ejection-type atomizer was proposed. The results of mathematical modeling of two-phase flow in the spray-jet and the crystallization process of fluid particles are given. The influence of the particle size, of the flow rate and the stagnation temperature gas in the ranges of industrial technology implemented for the production of powders aluminum of brands ASD, on the crystallization characteristics were investigated. The approximations of the characteristics of the crystallization process depending on the size of the aluminum particles on the basis of two approaches to the mathematical description of the process of crystallization of aluminum particles were obtained. The results allow to optimize the process parameters of ejection-type atomizer to produce aluminum particles with given morphology.

  20. Crystallization kinetics of partially crystallized Ti-5 Al powders obtained by rotating electrode process

    Energy Technology Data Exchange (ETDEWEB)

    Susic, M.; Zdujic, M.; Uskokovic, D.; Karanovic, L.

    1989-07-01

    Crystallization kinetics of partially crystallized Ti-5 Al alloy powders obtained by the rotating electrode processes have been studied by differential thermal and X-ray diffraction analyses. It is shown that only powders not exceeding a particle size of 90 /mu/m are characterized by a sharp irreversible exothermal peak in the DTA curve which can be ascribed to the crystallization of a residual amorphous phase. The crystallization process starts at 893 K and is fully completed at 1008 K having activation energies of 297 and 604 kJ/mol, thus indicating a very stable disordered structure. (orig.).

  1. Crystallization and polymorphism of triacylglycerols contribute to the rheological properties of processed cheese.

    Science.gov (United States)

    Gliguem, Hela; Ghorbel, Dorra; Lopez, Christelle; Michon, Camille; Ollivon, Michel; Lesieur, Pierre

    2009-04-22

    The thermal, rheological, and structural behaviors of a spreadable processed cheese were studied by complementary techniques including differential scanning calorimetry (DSC), rheology, and X-ray diffraction as a function of temperature. In this product, fat is present as a dispersed phase. Thermal and rheological properties were studied at different cooling rates between 0.5 and 10 degrees C min(-1) from 60 to 3 degrees C. Crystallization properties of fat were monitored at a cooling rate of -2 degrees C min(-1) from 60 to -10 degrees C. Fat triacylglycerols (TGs) crystallized at 15 degrees C in a triple-chain length 3Lalpha (72 A) structure correlated to exothermic events and to the sudden increase in the rheological moduli G' and G''. Upon heating at 2 degrees C min(-1), the polymorphic transition of TGs evidence the melting of the 3Lalpha structure and the formation of a 2Lbeta' (36.7-41.5 A) structure. Melting of the latter follows. These transformations coincide with thermal events observed by DSC and the decrease in two steps of the rheological moduli. The influence of fat crystallization, melting, and polymorphism upon the viscoelastic properties is clearly demonstrated upon both heating and cooling.

  2. Unsteady High Turbulence Effects on Turbine Blade Film Cooling Heat Transfer Performance Using a Transient Liquid Crystal Technique

    Science.gov (United States)

    Han, J. C.; Ekkad, S. V.; Du, H.; Teng, S.

    2000-01-01

    Unsteady wake effect, with and without trailing edge ejection, on detailed heat transfer coefficient and film cooling effectiveness distributions is presented for a downstream film-cooled gas turbine blade. Tests were performed on a five-blade linear cascade at an exit Reynolds number of 5.3 x 10(exp 5). Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. Coolant blowing ratio was varied from 0.4 to 1.2; air and CO2 were used as coolants to simulate different density ratios. Surface heat transfer and film effectiveness distributions were obtained using a transient liquid crystal technique; coolant temperature profiles were determined with a cold wire technique. Results show that Nusselt numbers for a film cooled blade are much higher compared to a blade without film injection. Unsteady wake slightly enhances Nusselt numbers but significantly reduces film effectiveness versus no wake cases. Nusselt numbers increase only slic,htly but film cooling, effectiveness increases significantly with increasing, blowing ratio. Higher density coolant (CO2) provides higher effectiveness at higher blowing ratios (M = 1.2) whereas lower density coolant (Air) provides higher 0 effectiveness at lower blowing ratios (M = 0.8). Trailing edge ejection generally has more effect on film effectiveness than on the heat transfer, typically reducing film effectiveness and enhancing heat transfer. Similar data is also presented for a film cooled cylindrical leading edge model.

  3. Nearly Monodispersion CoSm Alloy Nanoparticles Formed by an In-situ Rapid Cooling and Passivating Microfluidic Process

    Directory of Open Access Journals (Sweden)

    Henry Laurence

    2009-01-01

    Full Text Available Abstract An in siturapid cooling and passivating microfluidic processhas been developed for the synthesis of nearly monodispersed cobalt samarium nanoparticles (NPs with tunable crystal structures and surface properties. This process involves promoting the nucleation and growth of NPs at an elevated temperature and rapidly quenching the NP colloids in a solution containing a passivating reagent at a reduced temperature. We have shown that Cobalt samarium NPs having amorphous crystal structures and a thin passivating layer can be synthesized with uniform nonspherical shapes and size of about 4.8 nm. The amorphous CoSm NPs in our study have blocking temperature near 40 K and average coercivity of 225 Oe at 10 K. The NPs also exhibit high anisotropic magnetic properties with a wasp-waist hysteresis loop and a bias shift of coercivity due to the shape anisotropy and the exchange coupling between the core and the thin oxidized surface layer.

  4. Crystallization and cooling conditions for the diogenite formation in the turbulent magma ocean of the asteroid 4 Vesta

    CERN Document Server

    Kawabata, Yusuke

    2016-01-01

    The asteroid 4 Vesta has been completely differentiated to core and mantle despite its small size, of which surface materials are howardite-eucrite-diogenite (HED) meteorites that we know the detailed petrology, and therefore, is a good target for understanding differentiation of terrestrial planets. A new differentiation model for crust formation was developed by taking magma ocean fluid dynamics, chemical equilibrium, presence of $^{26}$Al, and cooling into consideration with special care to crystal separation. The role of crystal size, thickness of the conductive lid, and fO2 are evaluated as parameters. The results show that large crystals (1cm) settle and form a km-thick cumulate layer of orthopyroxene with Mg# of 0.70-0.90 in ~20 thousand years, which almost agrees with the Mg# of diogenites, whereas thinner layers are formed if the grain size is smaller.

  5. Process for cooling a solar cell and a combined photovoltaic and photothermic solar device

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, J.

    1982-07-13

    A solar cell cooling process is disclosed. The device implementing this process comprises a transparent assembly disposed in front of a photovoltaic cell. The transparent assembly, through which flows the cooling fluid leaving a radiator integral with the cell, absorbs the wavelengths greater than 1.1 micron. Thus, heating of the cell is limited and the fluid leaving the radiator is heated by the beam striking the cell.

  6. Detailing of deformation processes in polymeric crystals

    Science.gov (United States)

    Slutsker, A. I.; Vettegren', V. I.; Kulik, V. B.; Hilarov, V. L.; Polikarpov, Yu. I.; Karov, D. D.

    2015-11-01

    Structural changes in polymer crystals (polyethylene, polyimide, and others) have been studied using the X-ray diffraction and Raman spectroscopy methods under different influences: tensile loading along the chain molecule axis and heating from 90 to 350 K. An increase in the molecule axial length under loading and a decrease in the molecule axial length upon heating have been identified and measured using X-ray diffraction. A decrease in the skeletal vibration frequency during loading and heating has been identified and measured using Raman spectroscopy, which indicates an increase in the molecule contour length in both cases. A technique for determining the change in the polyethylene molecule contour length in the crystal from the measured change in the skeletal vibration frequency has been justified. The contributions of two components, namely, skeletal (carbon-carbon) bond stretching and the change (an increase during stretching and a decrease during heating) in the angle between skeletal bonds, to the longitudinal deformation of polyethylene crystals, have been quantitatively estimated. It has been shown that the negative thermal expansion (contraction) of the polymer crystal is caused by the dominant contribution of the decrease in the bond angle.

  7. Comparative analysis of different process simulation settings of a micro injection molded part featuring conformal cooling

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    2015-01-01

    different simulation models are established: a version including the part without the surrounding mold block, an advanced version including the mold block and conventional cooling channels, and a third version alike the second with additional conformal cooling for efficient thermal management...... of the implementation of the actual mold block, conventional cooling, and conformal cooling. In the comparison, characteristic quality criteria for injection molding are studied, such as the filling behavior of the cavity, the injection pressure, the temperature distribution, and the resulting part warpage....... Additionally, the analysis of the cooling channels exploiting computational fluid dynamics is introduced as helpful tool for the mold design process. It is observed that the comprehensive implementation of the actual injection molding system and conditions is highly relevant at sub-mm/micro dimensional scales...

  8. 2D InP photonic crystal fabrication process development

    NARCIS (Netherlands)

    Rong, B.; Van der Drift, E.; Van der Heijden, R.W.; Salemink, H.W.M.

    2006-01-01

    We have developed a reliable process to fabricate high quality 2D air-hole and dielectric column InP photonic crystals with a high aspect ratio on a STS production tool using ICP N2+Cl2 plasma. The photonic crystals have a triangular lattice with lattice constant of 400 nm and air-hole and dielectri

  9. Finding the Cold Needle in a Warm Haystack: Infrared Imaging Applied to Locating Cryo-cooled Crystals in Loops

    Science.gov (United States)

    Snell, Edward; vanderWoerd, Mark

    2003-01-01

    Thermally imaging the cryocooling processes of crystals has been demonstrated showing the progression of a cold wave through a crystal from the face closest to the origin of the coldstream ending at the point furthest away. During these studies large volume crystals were clearly distinguished from the loop holding them. Large volume crystals, used for neutron studies, were chosen deliberately to enhance the imaging. The different infrared transmission and reflectance properties of the crystal in comparison to the cryo-protectant are thought to be the parameter that produces the contrast making the crystal visible. As an application of the technology to locating crystals, more small crystals of lysozyme and a bFGF/dna complex were cryo-protected and imaged in large loops. The crystals were clearly distinguished from the vitrified solution. In the case of the bFGF/dna complex the illumination had to be carefully manipulated to enable the crystal to be seen in the visible spectrum. These preliminary results will be presented along with advantages and disadvantages of the technique and a discussion of how it might be applied.

  10. Microstructure, Precipitation, and Mechanical Properties of V-N-Alloyed Steel After Different Cooling Processes

    Science.gov (United States)

    Zhang, Jing; Wang, Fu-Ming; Yang, Zhan-Bing; Li, Chang-Rong

    2016-12-01

    Three cooling processes (direct air cooling, water cooling to 1023 K and 873 K (750 °C and 600 °C) followed by air cooling) after hot rolling are designed to develop V-N-alloyed 600 MPa grade high-strength steel for architectural construction. Microstructural characteristics, precipitation behavior, and mechanical properties were investigated. Experimental results indicate that all microstructures are composed of polygonal ferrite and pearlite. Compared to the microstructure obtained from traditional direct air cooling, the grain size of ferrite is refined from 6.5 to 4.6 μm and the interlamellar spacing of pearlite decreases from 136 to 45 nm, respectively, by the application of accelerated cooling and lower finish cooling temperature. The number fraction of high misorientation angle boundaries increases from 44 to 51 pct. Moreover, the sheet spacing of interphase precipitates decreases from (23 to 26 nm) to (14 to 17 nm) and the size of V(C,N) particles reduces from (5 to 8 nm) to (2 to 5 nm). Furthermore, the optimal mechanical properties are obtained in the steel water cooled to 873 K (600 °C), of which the yield strength, tensile strength, total elongation, uniform elongation, and impact energy at room temperature are 753 MPa, 922 MPa, 22 pct, 11 pct, and 36 J, respectively. Besides, the high yield strength is primarily attributed to the refined grains and precipitation hardening from interphase and random precipitation of nano-scale V(C,N) particles.

  11. Microstructure, Precipitation, and Mechanical Properties of V-N-Alloyed Steel After Different Cooling Processes

    Science.gov (United States)

    Zhang, Jing; Wang, Fu-Ming; Yang, Zhan-Bing; Li, Chang-Rong

    2016-09-01

    Three cooling processes (direct air cooling, water cooling to 1023 K and 873 K (750 °C and 600 °C) followed by air cooling) after hot rolling are designed to develop V-N-alloyed 600 MPa grade high-strength steel for architectural construction. Microstructural characteristics, precipitation behavior, and mechanical properties were investigated. Experimental results indicate that all microstructures are composed of polygonal ferrite and pearlite. Compared to the microstructure obtained from traditional direct air cooling, the grain size of ferrite is refined from 6.5 to 4.6 μm and the interlamellar spacing of pearlite decreases from 136 to 45 nm, respectively, by the application of accelerated cooling and lower finish cooling temperature. The number fraction of high misorientation angle boundaries increases from 44 to 51 pct. Moreover, the sheet spacing of interphase precipitates decreases from (23 to 26 nm) to (14 to 17 nm) and the size of V(C,N) particles reduces from (5 to 8 nm) to (2 to 5 nm). Furthermore, the optimal mechanical properties are obtained in the steel water cooled to 873 K (600 °C), of which the yield strength, tensile strength, total elongation, uniform elongation, and impact energy at room temperature are 753 MPa, 922 MPa, 22 pct, 11 pct, and 36 J, respectively. Besides, the high yield strength is primarily attributed to the refined grains and precipitation hardening from interphase and random precipitation of nano-scale V(C,N) particles.

  12. Liquid desiccant dehumidification and regeneration process to meet cooling and freshwater needs of desert greenhouses

    KAUST Repository

    Lefers, Ryan

    2016-04-19

    Agriculture accounts for ~70% of freshwater usage worldwide. Seawater desalination alone cannot meet the growing needs for irrigation and food production, particularly in hot, desert environments. Greenhouse cultivation of high-value crops uses just a fraction of freshwater per unit of food produced when compared with open field cultivation. However, desert greenhouse producers face three main challenges: freshwater supply, plant nutrient supply, and cooling of the greenhouse. The common practice of evaporative cooling for greenhouses consumes large amounts of fresh water. In Saudi Arabia, the most common greenhouse cooling schemes are fresh water-based evaporative cooling, often using fossil groundwater or energy-intensive desalinated water, and traditional refrigeration-based direct expansion cooling, largely powered by the burning of fossil fuels. The coastal deserts have ambient conditions that are seasonally too humid to support adequate evaporative cooling, necessitating additional energy consumption in the dehumidification process of refrigeration-based cooling. This project evaluates the use of a combined-system liquid desiccant dehumidifier and membrane distillation unit that can meet the dual needs of cooling and freshwater supply for a greenhouse in a hot and humid environment. © 2016 Balaban Desalination Publications. All rights reserved.

  13. Visualization of the Crystallization in Foam Extrusion Process

    Science.gov (United States)

    Tabatabaei Naeini, Alireza

    In this study, crystal formation of polypropylene (PP) and poly lactic acid (PLA) in the presence of CO2 in foam extrusion process was investigated using a visualization chamber and a CCD camera. The role of pre-existing crystals on the foaming behavior of PP and PLA were studied by characterizing the foam morphology. Visualization results showed that crystals formed within the die before foaming and these crystals affect the cell nucleation behavior and expansion ratio of PP and PLA significantly. Due to the fast crystallization kinetics of PP, crystallinity should be optimum to achieve uniform cell structure with high cell density and high expansion ratio. In PLA, enhancement of crystallinity is crucial for getting foam with a high expansion ratio. It was also visualized that CO2 significantly suppresses the crystallization temperature in PP through the plasticization effect as well as its influence on flow induced crystallinity.

  14. Influence of cooking time and cooling rate on the functionality and microstructure of processed cheese spreads

    Institute of Scientific and Technical Information of China (English)

    LI Xiaodong; WU Han; LIU Huaiwei

    2007-01-01

    The objective of this work was to study the influence of cooking time and cooling rate on functionality and microstructure of processed cheese spreads. When the cooking time was 20 min, the hardness and apparent viscosity were increased, and formed a homogenous, dense, and three-dimensional protein network, and a stronger gel was formed at this time. The slow cooling can increase the hardness and apparent viscosity of products, protein wall was thicker, and network was closer, so products can formed a stronger gel structure. The influence of cooking time on the functional properties was more significant than the influence of rapid cooling.

  15. Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation.

    Science.gov (United States)

    Schmidt, Marvin; Ullrich, Johannes; Wieczorek, André; Frenzel, Jan; Eggeler, Gunther; Schütze, Andreas; Seelecke, Stefan

    2016-05-02

    Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA's mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects - both important for efficient heat transfer from the medium to be cooled. The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the

  16. Process study and exergy analysis of a novel air separation process cooled by LNG cold energy

    Science.gov (United States)

    Xu, Wendong; Duan, Jiao; Mao, Wenjun

    2014-02-01

    In order to resolve the problems of the current air separation process such as the complex process, cumbersome operation and high operating costs, a novel air separation process cooled by LNG cold energy is proposed in this paper, which is based on high-efficiency heat exchanger network and chemical packing separation technology. The operating temperature range of LNG cold energy is widened from 133K-203K to 113K-283K by high-efficiency heat exchanger network and air separation pressure is declined from 0.5MPa to about 0.35MPa due to packing separation technology, thereby greatly improve the energy efficiency. Both the traditional and novel air separation processes are simulated with air handling capacity of 20t·h-1. Comparing with the traditional process, the LNG consumption is reduced by 44.2%, power consumption decrease is 211.5 kWh per hour, which means the annual benefit will be up to 1.218 million CNY. And the exergy efficiency is also improved by 42.5%.

  17. System design package for the solar heating and cooling central data processing system

    Science.gov (United States)

    1978-01-01

    The central data processing system provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. Overall software system requirements were established for use in the central integration facility which transforms raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems.

  18. Research and Development of Crystal Purification for Product of Uranium Crystallization Process

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K. [Japan Atomic Energy Agency - JAEA (Japan)

    2009-06-15

    Uranium crystallization has been developed as a part of advanced aqueous reprocessing for FBR spent fuel. Although the purity of uranyl nitrate hexahydrate (UNH) crystal from the crystallization process is supposed to meet a specification of FBR blanket fuel, an improvement of its purity is able to reduce the cost of fuel fabrication and storage (in case interim storage of recovered uranium is required). In this work, UNH crystal purification was developed as additional process after crystallization. Contamination of the crystal is caused by mother solution and solid state impurities. They are inseparable by washing and filtration. Mother solution on the surface of UNH crystals is removable by washing, but it is difficult to remove that in an obstructed part of crystalline aggregate by washing. Major elements of solid state impurities are cesium and barium. Cesium precipitates with tetravalent plutonium as a double nitrate, Cs{sub 2}Pu(NO{sub 3}){sub 6}. Barium crystallizes as Ba(NO{sub 3}){sub 2} because of its low solubility in nitric acid solution. It is difficult to separate their particle from UNH crystal by solid-liquid separation such as simple filtration. As a kind of crystal purification, there are some methods using sweating. Sweating is a phenomenon that a crystal melts partly below its melting point and it is caused by depression of freezing point due to impurity. It is considerably applicable for removal of mother solution. Concerning the solid state impurities, which has higher melting point than that of UNH crystal, it is supposed that they are separable by melting UNH crystal and filtration. The behaviors of impurities and applicability of sweating and melting-filtration operations to the purification for UNH crystal were investigated experimentally on a beaker and an engineering scale. With regard to behaviors of impurities, the conditions of cesium and barium precipitation were surveyed and it was clarified that there were most impurities on the

  19. Solid-State Laser Cooling of Ytterbium-Doped Tungstate Crystals

    Science.gov (United States)

    2001-01-01

    KGW but with a slightly higher cooling figure-of-merit,13 and zirconium-barium-lanthanum-aluminum- sodium fluoride glass ( ZBLAN ). This figure shows...namely the heavy metal fluoride glass ZBLAN and yttrium aluminum garnet. Favorable properties of the ytterbium-tungstates include exceptionally high...had shown net cooling was an ytterbium-doped heavy metal fluoride glass . Reasons for the lack of success with other materials include energy transfer

  20. Startup of Pumping Units in Process Water Supplies with Cooling Towers at Thermal and Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, V. V., E-mail: vberlin@rinet.ru; Murav’ev, O. A., E-mail: muraviov1954@mail.ru; Golubev, A. V., E-mail: electronik@inbox.ru [National Research University “Moscow State University of Civil Engineering,” (Russian Federation)

    2017-03-15

    Aspects of the startup of pumping units in the cooling and process water supply systems for thermal and nuclear power plants with cooling towers, the startup stages, and the limits imposed on the extreme parameters during transients are discussed.

  1. Process for Forming a High Temperature Single Crystal Canted Spring

    Science.gov (United States)

    DeMange, Jeffrey J (Inventor); Ritzert, Frank J (Inventor); Nathal, Michael V (Inventor); Dunlap, Patrick H (Inventor); Steinetz, Bruce M (Inventor)

    2017-01-01

    A process for forming a high temperature single crystal canted spring is provided. In one embodiment, the process includes fabricating configurations of a rapid prototype spring to fabricate a sacrificial mold pattern to create a ceramic mold and casting a canted coiled spring to form at least one canted coil spring configuration based on the ceramic mold. The high temperature single crystal canted spring is formed from a nickel-based alloy containing rhenium using the at least one coil spring configuration.

  2. Biofouling reduction in recirculating cooling systems through biofiltration of process water.

    Science.gov (United States)

    Meesters, K P H; Van Groenestijn, J W; Gerritse, J

    2003-02-01

    Biofouling is a serious problem in industrial recirculating cooling systems. It damages equipment, through biocorrosion, and causes clogging and increased energy consumption, through decreased heat transfer. In this research a fixed-bed biofilter was developed which removed assimilable organic carbon (AOC) from process water, thus limiting the major substrate for the growth of biofouling. The biofilter was tested in a laboratory model recirculating cooling water system, including a heat exchanger and a cooling tower. A second identical model system without a biofilter served as a reference. Both installations were challenged with organic carbon (sucrose and yeast extract) to provoke biofouling. The biofilter improved the quality of the recirculating cooling water by reducing the AOC content, the ATP concentration, bacterial numbers (30-40 fold) and the turbidity (OD660). The process of biofouling in the heat exchangers, the process water pipelines and the cooling towers, was monitored by protein increase, heat transfer resistance, and chlorine demanded for maintenance. This revealed that biofouling was lower in the system with the biofilter compared to the reference installation. It was concluded that AOC removal through biofiltration provides an attractive, environmental-friendly means to reduce biofouling in industrial cooling systems.

  3. A Robust Process Analytical Technology (PAT) System Design for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    for generation of the supersaturation setpoint for a supersaturation controller, a tool for design of a process monitoring and control system (also called Process Analytical Technology (PAT) system) as well as a tool for performing uncertainty and sensitivity analysis of the PAT system design. The uncertainty......A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations. The design framework contains a generic multidimensional modelling framework, a tool...... crystallization process to achieve the target crystal size distribution (CSD) in the presence of parametric uncertainties....

  4. Single crystal Processing and magnetic properties of gadolinium nickel

    Energy Technology Data Exchange (ETDEWEB)

    Shreve, Andrew John [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd2O3 W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.

  5. Study on temper-rapid cooling process of low carbon steel produced by CSP

    Institute of Scientific and Technical Information of China (English)

    Huajie Wu; Yangchun Liu; Jie Fu

    2007-01-01

    On the basis of the effect of carbon precipitation on the microstructure and properties of steel products below A1 temperature,a new thermal treatment method (temper-rapid cooling process) was studied. By the temper-rapid cooling process, the yield strengths of the high strength low carbon (HSLC) steel ZJ330 and SPA-H produced using the compact strip production (CSP) process increased from 340 to about 410 MPa and from 410 to about 450 MPa, respectively. The results indirectly indicated that there existed nanoscaled iron-carbon precipitates that have obvious precipitation effect on low carbon steel produced by CSP. The prospect of application is discussed.

  6. Attaining 186-nm light generation in cooled beta-BaB(2)O(4) crystal.

    Science.gov (United States)

    Kouta, H; Kuwano, Y

    1999-09-01

    The transparency range of beta-BaB(2)O(4) (BBO) was expanded by means of cooling, and the resulting absorption coefficient at 193.4 nm was reduced to 0.29cm(-1) at 91 K from 1.39cm(-1) at 295 K. Further, generation of light at 186.0 nm (the measurement limit in air) by type I sum-frequency generation (SFG) based on fundamental (744-nm) and third-harmonic (248-nm) light from a Ti:sapphire laser was confirmed for cooled BBO. Calculations based on observed data for SFG wavelengths and phase-matching angles indicate a potential for cooled BBO to generate wavelengths as low as 181.7 nm.

  7. Dimensional accuracy of internal cooling channel made by selective laser melting (SLM And direct metal laser sintering (DMLS processes in fabrication of internally cooled cutting tools

    Directory of Open Access Journals (Sweden)

    Ghani S. A. C.

    2017-01-01

    Full Text Available Selective laser melting(SLM and direct metal laser sintering(DMLS are preferred additive manufacturing processes in producing complex physical products directly from CAD computer data, nowadays. The advancement of additive manufacturing promotes the design of internally cooled cutting tool for effectively used in removing generated heat in metal machining. Despite the utilisation of SLM and DMLS in a fabrication of internally cooled cutting tool, the level of accuracy of the parts produced remains uncertain. This paper aims at comparing the dimensional accuracy of SLM and DMLS in machining internally cooled cutting tool with a special focus on geometrical dimensions such as hole diameter. The surface roughness produced by the two processes are measured with contact perthometer. To achieve the objectives, geometrical dimensions of identical tool holders for internally cooled cutting tools fabricated by SLM and DMLS have been determined by using digital vernier calliper and various magnification of a portable microscope. In the current study, comparing internally cooled cutting tools made of SLM and DMLS showed that generally the higher degree of accuracy could be obtained with DMLS process. However, the observed differences in surface roughness between SLM and DMLS in this study were not significant. The most obvious finding to emerge from this study is that the additive manufacturing processes selected for fabricating the tool holders for internally cooled cutting tool in this research are capable of producing the desired internal channel shape of internally cooled cutting tool.

  8. PATI RESISTEN SAGU HASIL PROSES HIDROLISIS ASAM DAN AUTOCLAVING-COOLING [Resistant Starch of Sago from Acid Hydrolyzis and Autoclaving-Cooling Processes

    Directory of Open Access Journals (Sweden)

    Feri Kusnandar

    2015-07-01

    Full Text Available The aim of this study was to produce resistant starch (RS from a combination of acid hydrolysis and autoclaving-cooling processes of sago starch. This study compared two methods of starch modification to produce RS, i.e. (1 acid hydrolysis treatment followed by autoclaving-cooling cycles (AH-AC, and (2 autoclaving-cooling cycles followed by acid hydrolysis treatment (AC-AH. The acid hydrolysis used 1 and 2% HCl while autoclaving-cooling process consisted of three-cycle of autoclaving at 121°C for 30 min followed by cooling at 4°C for 72 hrs. Both AH-AC and AC-AH modification methods decreased starch content, altered amylose and amylopectin ratio, and increased RS contents. Both modification methods also yielded nearly flat pasting profiles at both heating and cooling phases as compared to that of native sago starch. At the same HCl concentration, the AH-AC process yielded a higher RS content than that of AC-AH. Among all treatments, the acid hydrolysis treatment using 1% HCl followed by three cycles of autoclaving-cooling process yielded the highest RS content (74.28%. The crystallinity of RS was also lower than of native sago starch, but its A crystalline type remained the same.

  9. Perturbative Analysis of Two-Temperature Radiative Shocks with Multiple Cooling Processes

    CERN Document Server

    Saxton, C J; Saxton, Curtis J.; Wu, Kinwah

    1999-01-01

    The structure of the hot downstream region below a radiative accretion shock, such as that of an accreting compact object, may oscillate due to a global thermal instability. The oscillatory behaviour depends on the functional forms of the cooling processes, the energy exchanges of electrons and ions in the shock-heated matter, and the boundary conditions. We analyse the stability of a shock with unequal electron and ion temperatures, where the cooling consists of thermal bremsstrahlung radiation which promotes instability, plus a competing process which tends to stabilize the shock. The effect of transverse perturbations is considered also. As an illustration, we study the special case in which the stabilizing cooling process is of order 3/20 in density and 5/2 in temperature, which is an approximation for the effects of cyclotron cooling in magnetic cataclysmic variables. We vary the efficiency of the second cooling process, the strength of the electron-ion exchange and the ratio of electron and ion pressure...

  10. A liquid crystal thermography calibration with true color image processing

    Institute of Scientific and Technical Information of China (English)

    Yu Rao; Shusheng Zang; Minghai Huang

    2009-01-01

    Liquid crystal thermography is a high-resolution,non-intrusive optical technique for full-field temperature measurement.We present the detailed calibration data for the thermochromic liquid crystal(TLC)with a usefill range of 41-60 ℃.The calibration is done with true color image processing by using an isothermal calibrator.The hue-temperature curve of the TLC is obtained,and the measurement uncertainty is analyzed.Combined with the image noise reduction technique of a 5×5 median filter,the measurement accuracy of the liquid crystal thermography can be significantly improved by approximately 57.1%.

  11. Crystallization processes in pharmaceutical technology and drug delivery design

    Science.gov (United States)

    Shekunov, B. Yu; York, P.

    2000-04-01

    Crystallization is a major technological process for particle formation in pharmaceutical industry and, in addition, plays an important role in defining the stability and drug release properties of the final dosage forms. Industrial and regulatory aspects of crystallization are briefly reviewed with reference to solid-state properties of pharmaceuticals. Crystallization, incorporating wider definition to include precipitation and solid-state transitions, is considered in terms of preparation of materials for direct compression, formation of amorphous, solvated and polymorphic forms, chiral separation of drugs, production of materials for inhalation drug delivery and injections. Finally, recent developments in supercritical fluid particle technology is considered in relationship to the areas discussed.

  12. Numerical Simulation of Injection Molding Cooling Process Based on 3D Surface Model

    Institute of Scientific and Technical Information of China (English)

    CUIShu-biao; ZHOUHua-min; LIDe-qun

    2004-01-01

    The design of the coohng system of injection molds directly affects both productivity and the quality of the final part. Using the cooling process CAE system to instruct the mold design, the efficiency and quality of design can be improved greatly. At the same time, it is helpful to confirm the cooling system structure and optimize the process conditions. In this paper, the 3D surface model of mold cavity is used to replace the middle-plane model in the simulation by Boundary Element Method, which break the bottleneck of the application of the injection molding simulation softwares base on the middle-plane model. With the improvements of this paper, a practical and commercial simulation software of injection molding cooling process named as HsCAE3D6.0 is developed.

  13. System design package for the solar heating and cooling central data processing system

    Energy Technology Data Exchange (ETDEWEB)

    1978-03-01

    This system design package for the Central Data Processing System consists of the Software Performance Specification, Hardware Performance Specification, Software Verification Plan, CDPS Development Program, Qualification and Acceptance Test Procedures, Qualification Test and Analysis Report, and Qualification and Acceptance Test Review. The Central Data Processing System, located at IBM's Federal System Division facility in Huntsville, Alabama, provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications.

  14. Preliminary design review package for the solar heating and cooling central data processing system

    Energy Technology Data Exchange (ETDEWEB)

    1976-05-25

    This preliminary design review package, consisting of the Software Performance Specification, Hardware Performance Specification, and the Verification Plan for the Central Data Processing System (CDPS), was prepared by the IBM Corporation. The Central Data Processing System, located at IBM's FSD facility in Huntsville, Alabama, provides the resources required to assess the performance of solar heating and cooling systems at remote sites. These sites include residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications.

  15. Composition dependence of spontaneous crystallization of phosphosilicate glass melts during cooling

    DEFF Research Database (Denmark)

    Liu, S.J.; Zhu, C.F.; Zhang, Y.F.

    2012-01-01

    and crystallization degree. It is found that adding NaF into the studied compositions slightly decreases melt fragility and improves both the glass-forming ability and melt workability. This effect is associated with the unique structural role of NaF compared to the other modifier oxides. It is also found...... that the onset viscosity of crystallization can be used as a parameter for describing both glass-forming ability and melt workability....

  16. Progress in modeling of fluid flows in crystal growth processes

    Institute of Scientific and Technical Information of China (English)

    Qisheng Chen; Yanni Jiang; Junyi Yan; Ming Qin

    2008-01-01

    Modeling of fluid flows in crystal growth processes has become an important research area in theoretical and applied mechanics.Most crystal growth processes involve fluid flows,such as flows in the melt,solution or vapor.Theoretical modeling has played an important role in developing technologies used for growing semiconductor crystals for high performance electronic and optoelectronic devices.The application of devices requires large diameter crystals with a high degree of crystallographic perfection,low defect density and uniform dopant distribution.In this article,the flow models developed in modeling of the crystal growth processes such as Czochralski,ammono-thermal and physical vapor transport methods are reviewed.In the Czochralski growth modeling,the flow models for thermocapillary flow,turbulent flow and MHD flow have been developed.In the ammonothermal growth modeling,the buoyancy and porous media flow models have been developed based on a single-domain and continuum approach for the composite fluid-porous layer systems.In the physical vapor transport growth modeling,the Stefan flow model has been proposed based on the flow-kinetics theory for the vapor growth.In addition,perspectives for future studies on crystal growth modeling are proposed.

  17. Mass production and photoelectric performances of P and Al Co-doped ZnO nanocrystals under different cooling post-processes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Ya-Juan; Lu, Yi [Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai 200237 (China); Liu, Jin-Ku, E-mail: jkliu@ecust.edu.cn [Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai 200237 (China); Yang, Xiao-Hong, E-mail: yxh6110@yeah.net [Department of Chemistry, Chizhou University, Chizhou 247000 (China)

    2015-11-05

    The phosphorus and aluminum co-doped in zinc oxide (ZnO) called PAZO nano-crystals (NCs) have been mass synthesized by a combustion method, which shows a preferable photocatalytic capability and conductive ability. This article focuses on the properties of PAZO NCs experienced by three cooling-down aftertreatments, which were the normalizing, quenching and annealing process, respectively. The influences of different cooling processes on the photocatalytic and conductive performances are discussed in details. From the research, we found the quenched-PAZO NCs showed the most unappealing photocatalysis and conductivity, because excessive defects as the recombination center of electron–hole pairs were generated in the quenching process. - Graphical abstract: This research focuses on the PAZO NCs experienced by different cooling-down aftertreatments, which were the normalizing, quenching and annealing process, respectively. The quenched-PAZO NCs had the most unappealing photocatalysis and conductivity, because of generating excessive defects as the recombination center of electron–hole pairs in the quenching process. - Highlights: • We presented a method to mass synthesize co-doped P and Al in ZnO nanocrystals. • The PAZO NCs have novel photoelectric performances. • The cooling post-process influence on the photoelectric properties was studied. • The excessive defects decline the photocatalytic and conductive activities.

  18. Pressure Effects on Solid State Phase Transformation of Aluminium Bronze in Cooling Process

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-Yan; CHEN Yan; LIU Yu-Wen; LI Fei; LIU Jian-Hua; PENG Gui-Rong; WANG Wen-Kui

    2009-01-01

    Effects of high pressure (6 GPa) on the solid state phase transformation kinetic parameters of aluminum bronze during the cooling process are investigated, based on the measurement and calculation of its solid state phase transformation temperature, duration and activation energy and the observation of its microstructures. The results show that high pressure treatment can reduce the solid phase transformation temperature and activation energy in the cooling process and can shorten the phase transformation duration, which is favorable when forming fine-grained aluminum bronze.

  19. Simulation of Uranyl Nitrate Crystallization Process in Linear Crystallizer Using Simsar Software

    Science.gov (United States)

    Ochoa Bique, A.; Gozhimov, A.; Chursin, Yu; Schmidt, O.

    2016-08-01

    The paper deals with simulation of linear crystallizer work process for the research of technic operating modes and searching the most effective for material's nano-purity achievement. The model is realized by using SimSar software. Importance of device's geometry and process variables are marked. The model was included in the complex's composition of closed nuclear fuel cycle.

  20. Tube failures due to cooling process problem and foreign materials in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, J. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia); Purbolaksono, J., E-mail: judha@uniten.edu.m [Department of Mechanical Engineering, Universiti Tenaga Nasional, Km 7 Jalan Kajang-Puchong, Kajang 43009, Selangor (Malaysia); Beng, L.C. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia)

    2010-07-15

    Cooling process which uses water for heat transfer is an essential factor in coal-fired and nuclear plants. Loss of cooling upset can force the plants to shut down. In particular, this paper reports visual inspections and metallurgical examinations on the failed SA210-A1 right-hand side (RHS) water wall tube of a coal-fired plant. The water wall tube showed the abnormal outer surface colour and has failed with wide-open ductile rupture and thin edges indicating typical signs of short-term overheating. Metallurgical examinations confirmed the failed tube experiencing higher temperature operation. Water flow starvation due to restriction inside the upstream tube is identified as the main root cause of failure. The findings are important to take failure mitigation actions in the future operation. Discussion on the typical problems related to the cooling process in nuclear power plants is also presented.

  1. Medios de enfriamiento para el temple // Means for Cooling During the Hardening Process

    Directory of Open Access Journals (Sweden)

    N. Caballero Stevens

    1999-07-01

    Full Text Available Los factores que rigen el proceso de temple son la temperatura, el tiempo de calentamiento y la velocidad de enfriamiento.Tradicionalmente, la variación de la velocidad de enfriamiento se ha logrado mediante la utilización de diferentes medios como elagua, aceites minerales, aceites orgánicos, metales fundidos y otros.En este trabajo, se presentan las características fundamentales de los medios convencionales y actuales empleados para elenfriamiento durante el temple.Palabras claves: Endurecimiento superficial, temple superficial, medios de enfriamiento._____________________________________________________________________AbstractFactors governing of the hardening process are temperature, heating time and cooling speed. Traditionally, the variation of thecooling time has been achieved by using different means such as water, mineral oils, molten metals, etc.In this work, the fundamental characteristics of the conventional and modern means developed for cooling during the hardeningprocess are presented.Key words: Hardening process, cooling means.

  2. A Robust Process Analytical Technology (PAT) System Design for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations. The design framework contains a generic multidimensional modelling framework, a tool for gen...

  3. Crystal Growth Behaviors of Silicon during Melt Growth Processes

    Directory of Open Access Journals (Sweden)

    Kozo Fujiwara

    2012-01-01

    Full Text Available It is imperative to improve the crystal quality of Si multicrystal ingots grown by casting because they are widely used for solar cells in the present and will probably expand their use in the future. Fine control of macro- and microstructures, grain size, grain orientation, grain boundaries, dislocation/subgrain boundaries, and impurities, in a Si multicrystal ingot, is therefore necessary. Understanding crystal growth mechanisms in melt growth processes is thus crucial for developing a good technology for producing high-quality Si multicrystal ingots for solar cells. In this review, crystal growth mechanisms involving the morphological transformation of the crystal-melt interface, grain boundary formation, parallel-twin formation, and faceted dendrite growth are discussed on the basis of the experimental results of in situ observations.

  4. Introducing uncertainty analysis of nucleation and crystal growth models in Process Analytical Technology (PAT) system design of crystallization processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    This paper presents the application of uncertainty and sensitivity analysis as part of a systematic modelbased process monitoring and control (PAT) system design framework for crystallization processes. For the uncertainty analysis, the Monte Carlo procedure is used to propagate input uncertainty......, while for sensitivity analysis, global methods including the standardized regression coefficients (SRC) and Morris screening are used to identify the most significant parameters. The potassium dihydrogen phosphate (KDP) crystallization process is used as a case study, both in open-loop and closed...

  5. A systematic framework for design of process monitoring and control (PAT) systems for crystallization processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    for generation of the supersaturation set-point for supersaturation control, as well as a tool for design of a process monitoring and control system (also called Process Analytical Technology (PAT) system). This systematic design allows one to generate the necessary problem-chemical system specific model......A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations.The systematic design framework contains a generic crystallizer modelling toolbox, a tool......, the necessary supersaturation set-point as well as a PAT system design including implementation of monitoring tools and control strategies in order to produce the desired target product properties notably crystal size distribution (CSD) and shape for a wide range of crystallization processes. Application...

  6. Downstream Processability of Crystal Habit-Modified Active Pharmaceutical Ingredient

    DEFF Research Database (Denmark)

    Pudasaini, Nawin; Upadhyay, Pratik Pankaj; Parker, Christian Richard

    2017-01-01

    Efficient downstream processing of active pharmaceutical ingredients (APIs) can depend strongly on their particulate properties, such as size and shape distributions. Especially in drug products with high API content, needle-like crystal habit of an API may show compromised flowability and tablet......Efficient downstream processing of active pharmaceutical ingredients (APIs) can depend strongly on their particulate properties, such as size and shape distributions. Especially in drug products with high API content, needle-like crystal habit of an API may show compromised flowability...

  7. Two-Step Processes and IR Recording in Photorefractive Crystals

    Science.gov (United States)

    Kraetzig, Eckhard; Buse, Karsten

    Two-step excitation processes have been used for hologram storage in photorefractive crystals. By this means the interference pattern can be formed with red or near-IR light and nondestructive readout of information is possible. Often shallow levels are involved in the holographic recording process in photorefractive crystals. The shallow levels can be populated by illumination with visible or UV pulses forming states with relatively long lifetimes, thus sensitizing the crystals for holographic recording with IR pulses. In LiNbO3 and LiTaO3 the most important shallow levels have been identified. They result from NbLi^5+ and TaLi^5+ antisite defects (Nb5+ or Ta5+ on Li+ site). The crystals can also be pre-illuminated with visible light from a cw argon laser or a xenon lamp and holograms can be recorded with red light from a laser diode. The sensitization process is possible for other photorefractive crystals, too. The holograms can be read nondestructively with IR light and can be erased with green light. The hologram lifetime is limited by electron tunneling or by an ionic conductivity. Lifetimes up to years can be achieved. Recording of components for telecommunication applications with IR light allows one to create reconfigurable and thus more versatile devices.

  8. IR recording in photorefractive crystals via two-step processes

    Science.gov (United States)

    Kraetzig, Eckhard E.

    2002-01-01

    Two-step excitation processes have been used for hologram storage in photorefractive crystals. Then the interference pattern can be formed with red or near-IR light and nondestructive readout of information is possible. Often shallow levels are involved in the holographic recording process in photorefractive crystals. The shallow levels can be populated by illumination with visible or UV pulses forming states with relatively long life times, thus sensitizing the crystals for holographic recording with IR pulses. In LiNbO3 and LiTaO3 the most important shallow levels have been identified. They result from NbLi5+ and TaLi5+ antisite defects (Nb5+ or Ta5+ on Li+ site). The crystals can also be pre-illuminated with visible light of a cw argon laser or of a Xenon lamp and holograms can be recorded with red light of a laser diode. The sensitization process is possible for other photorefractive crystals, too. The holograms can be read nondestructively with IR light and can be erased with green light.

  9. A white dwarf cooling age of 8 Gyr for NGC 6791 from physical separation processes

    CERN Document Server

    García-Berro, Enrique; Althaus, Leandro G; Renedo, Isabel; Lorén-Aguilar, Pablo; Córsico, Alejandro H; Rohrmann, René D; Salaris, Maurizio; Isern, Jordi

    2010-01-01

    NGC 6791 is a well studied open cluster1 that it is so close to us that can be imaged down to very faint luminosities. The main sequence turn-off age (~8 Gyr) and the age derived from the termination of the white dwarf cooling sequence (~6 Gyr) are significantly different. One possible explanation is that as white dwarfs cool, one of the ashes of helium burning, 22Ne, sinks in the deep interior of these stars. At lower temperatures, white dwarfs are expected to crystallise and phase separation of the main constituents of the core of a typical white dwarf, 12C and 16O, is expected to occur. This sequence of events is expected to introduce significant delays in the cooling times, but has not hitherto been proven. Here we report that, as theoretically anticipated, physical separation processes occur in the cores of white dwarfs, solving the age discrepancy for NGC 6791.

  10. CO2 hydrates for cooling processes in the meat packing industry; CO2-hydraten voor koelprocessen in de vleesverwerking

    Energy Technology Data Exchange (ETDEWEB)

    Infante Ferreira, C.A. [Technische Universiteit Delft TUD, Delft (Netherlands)

    2012-11-15

    In the 90s of the last century ice-slurries were introduced as a method to make indirect cooling systems economically attractive. The melting of the ice crystals ensures a large heat capacity, a constant temperature during heat transfer, and higher heat transfer coefficients during the recording process. The disadvantage of this is that ice slurries can be formed only below 0C. Applications with a cooling demand above 0C should still be controlled with indirect systems with operating temperatures below 0C [Dutch] In de jaren 90 van de vorige eeuw zijn ijsslurries geintroduceerd als een methode om indirecte koelsystemen economisch aantrekkelijk te maken. Het smeltproces van de ijskristallen zorgt voor een grote warmtecapaciteit (dus kleine stromen), een constante temperatuur tijdens warmteoverdracht (dus hogere werktemperaturen) en grotere warmteoverdrachtscoëfficiënten tijdens het warmteopnameproces. Nadeel van deze slurries is dat ijs alleen onder 0C gevormd kan worden. Toepassingen met een koelvraag boven de 0C moesten toch worden bediend met indirecte systemen met werktemperaturen onder de 0C.

  11. Selected Parameters of Micro-Jet Cooling Gases in Hybrid Spraying Process

    Directory of Open Access Journals (Sweden)

    Szczucka-Lasota B.

    2016-06-01

    Full Text Available The innovative technology, like thermal spraying with a micro-jet cooling is one of the important modification of classical ultrasonic spraying methods. Using of micro-stream with gases like argon or nitrogen allows to cool the coating immediately after spraying, and thereby reduce the time of transition during the injection of each layer. As a result of the process, the fine dispersive structure of coatings is obtained during the shorter time in comparable to the classical high velocity oxygen fuel process (HVOF. The parameter of process and the type of stream equipment determine the quality of the obtained structure and thermal stress in the coating. The article presents the relationship between selected parameters of hybrid process and properties of the coatings. The presented technology should be adapted to the actual production of protective coating for machines and construction working in wear conditions.

  12. Effect of process parameters on crystal size and morphology of lactose in ultrasound-assisted crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Patel, S.R.; Murthy, Z.V.P. [Chemical Engineering Department, S.V. National Institute of Technology, Surat - 395 007, Gujarat (India)

    2011-03-15

    {alpha}-lactose monohydrate is widely used as a pharmaceutical excipient. Drug delivery system requires the excipient to be of narrow particle size distribution with regular particle shape. Application of ultrasound is known to increase or decrease the growth rate of certain crystal faces and controls the crystal size distribution. In the present paper, effect of process parameters such as sonication time, anti-solvent concentration, initial lactose concentration and initial pH of sample on lactose crystal size, shape and thermal transition temperature was studied. The parameters were set according to the L{sub 9}-orthogonal array method at three levels and recovered lactose from whey by sonocrystallization. The recovered lactose was analyzed by particle size analyzer, scanning electron microscopy and differential scanning calorimeter. It was found that the morphology of lactose crystal was rod/needle like shape. Crystal size distribution of lactose was observed to be influenced by different process parameters. From the results of analysis of variance, the sonication time interval was found to be the most significant parameter affecting the volume median diameter of lactose with the highest percentage contribution (74.28%) among other parameters. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Introducing uncertainty analysis of nucleation and crystal growth models in Process Analytical Technology (PAT) system design of crystallization processes.

    Science.gov (United States)

    Samad, Noor Asma Fazli Abdul; Sin, Gürkan; Gernaey, Krist V; Gani, Rafiqul

    2013-11-01

    This paper presents the application of uncertainty and sensitivity analysis as part of a systematic model-based process monitoring and control (PAT) system design framework for crystallization processes. For the uncertainty analysis, the Monte Carlo procedure is used to propagate input uncertainty, while for sensitivity analysis, global methods including the standardized regression coefficients (SRC) and Morris screening are used to identify the most significant parameters. The potassium dihydrogen phosphate (KDP) crystallization process is used as a case study, both in open-loop and closed-loop operation. In the uncertainty analysis, the impact on the predicted output of uncertain parameters related to the nucleation and the crystal growth model has been investigated for both a one- and two-dimensional crystal size distribution (CSD). The open-loop results show that the input uncertainties lead to significant uncertainties on the CSD, with appearance of a secondary peak due to secondary nucleation for both cases. The sensitivity analysis indicated that the most important parameters affecting the CSDs are nucleation order and growth order constants. In the proposed PAT system design (closed-loop), the target CSD variability was successfully reduced compared to the open-loop case, also when considering uncertainty in nucleation and crystal growth model parameters. The latter forms a strong indication of the robustness of the proposed PAT system design in achieving the target CSD and encourages its transfer to full-scale implementation.

  14. Thin film process forms effective electrical contacts on semiconductor crystals

    Science.gov (United States)

    Formigoni, N. P.; Roberts, J. S.

    1967-01-01

    Process makes microscopic, low-resistance electrical contacts on hexagonal n-type silicon carbide crystals used for microelectronic devices. A vacuum deposition of aluminum is etched to expose the bare silicon carbide where the electrical contacts are made. Sputtering alternating layers of tantalum and gold forms the alloy film.

  15. Silica and Pyroxene in IVA Irons; Possible Formation of the IVA Magma by Impact Melting and Reduction of L-LL-Chondrite Materials Followed by Crystallization and Cooling

    Science.gov (United States)

    Wasson, John T.; Matsunami, Yoshiyuki; Rubin, Alan E.

    2006-01-01

    Group IVA is a large magmatic group of iron meteorites. The mean DELTA O-17 (= delta O-17 - 0.52(raised dot) delta O-18) of the silicates is approx. plus or minus 1.2%o, similar to the highest values in L chondrites and the lowest values in LL chondrites; delta O-18 values are also in the L/LL range. This strongly suggests that IVA irons formed by melting L-LL parental material, but the mean Ni content of IVA irons (83 mg/g) is much lower than that of a presumed L-LL parent (approx. 170 mg/g) and the low-Ca pyroxene present in two IVA meteorites is Fs13, much lower than the Fs20-29 values in L and LL chondrites. Thus, formation from L-LL precursors requires extensive addition of metallic Fe, probably produced by reduction of FeS and FeO. Group IVA also has S/Ni, Ga/Ni, and Ge/Ni ratios that are much lower than those in L-LL chondrites or any chondrite group that preserves nebular compositions, implying loss of these volatile elements during asteroidal processing. We suggest that these reduction and loss processes occurred near the surface of the asteroid during impact heating, and resulted partly from reduction by C, and partly from the thermal dissociation of FeS and FeO with loss of O and S. The hot (approx. 1770 K) low-viscosity melt quickly moved through channels in the porous asteroid to form a core. Two members of the IVA group, Sao Joao Nepomuceno (hereafter, SJN) and Steinbach, contain moderate amounts of orthopyroxene and silica, and minor amounts of low-Ca clinopyroxene. Even though SJN formed after approx. 26% crystallization and Steinbach formed after approx. 77% Crystallization of the IVA core, both could have originated within several tens of meters of the core-mantle interface if 99% of the crystallization occurred from the center outwards. Two other members of the group (Gibeon and Bishop Canyon) contain tabular tridymite, which we infer to have initially formed as veins deposited from a cooling SiO-rich vapor. The silicates were clearly introduced

  16. Modelling of transport phenomena and defects in crystal growth processes

    Indian Academy of Sciences (India)

    S Pendurti; H Zhang; V Prasad

    2001-02-01

    A brief review of single crystal growth techniques and the associated problems is presented. Emphasis is placed on models for various transport and defect phenomena involoved in the growth process with the ultimate aim of integrating them into a comprehensive numerical model. The sources of dislocation nucleation in the growing crystal are discussed, and the propagation and multiplication of these under the action of thermal stresses is discussed. A brief description of a high-level numerical technique based on multiple adaptive grid generation and finite volume discretization is presented, followed by the result of a representative numerical simulation.

  17. Calorimetric analysis of heating and cooling process of nodular cast iron

    Directory of Open Access Journals (Sweden)

    Bińczyk F.

    2007-01-01

    Full Text Available The study presents the results of investigations of the thermal effects which take place during heating and cooling of samples of the nodular graphite cast iron taken from the stepped test casting of the wall thicknesses amounting to 5, 10, 15 and 20 mm. For investigations, a differential scanning calorimeter, type Multi HTC S60, was used. During heating, three endothermic effects related with pearlite decomposition, phase transformation α → γ, and carbon dissolution in austenite were observed on a DSC diagram. During cooling, two exothermic effects related with phase transformation γ→ α and pearlite formation were observed to consecutively take place on a DSC diagram. The values of the enthalpy of these processes differ and depend on the initial microstructure of the examined samples. The metallic matrix in 5 mm sample after the process of heating and cooling changes totally in favour of ferrite. The same effect, though less advanced in intensity, takes place in 10 mm sample, while in 15 and 20 mm samples the matrix constitution remains unchanged. The higher is the content of ferrite in samples, the stronger is the endothermic effect of the α → γ transformation and the weaker is the endothermic effect related with carbon dissolution in austenite. The total of the endothermic effects (heating is reduced, while that of the exothermic effects (cooling increases along with the increasing thickness of walls in a stepped test casting, from which samples for the investigations were taken.

  18. Effect of titanium dioxide (TiO{sub 2}) on largely improving solar reflectance and cooling property of high density polyethylene (HDPE) by influencing its crystallization behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shichao; Zhang, Jun, E-mail: zhangjun@njtech.edu.cn

    2014-12-25

    Highlights: • HDPE/TiO{sub 2} composites have more perfect crystal structure. • Refractive index is the key factor affecting the final solar reflectance. • HDPE/TiO{sub 2} composites can achieve high solar reflectance. • The real cooling property is in accordance with solar reflectance. - Abstract: In this study, the different crystal forms of titanium dioxide (TiO{sub 2}) were added into high density polyethylene (HDPE) to fabricate cool material. Crystal structure, crystallization behavior, crystal morphology were investigated by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized optical microscope (POM). Scanning electron microscope (SEM) was applied to observe dispersion of TiO{sub 2} particles in the HDPE matrix and the cross section morphology. The solar reflectance and actual cooling property were evaluated by UV–Vis–NIR spectrometer and a self-designed device. By adding TiO{sub 2} particles into HDPE matrix, the polymer chain could crystallize into more perfect and thermal stable lamella. The presence of TiO{sub 2} particles dramatically increased the number of nucleation site therefore decreased the crystal size. The subsequent solar reflectance was related to the degree of crystallinity, the spherulite size of HDPE, refractive index, and distribution of TiO{sub 2} particles in HDPE matrix. It was found the rutile TiO{sub 2} could largely improve the total solar reflectance from 28.2% to 51.1%. Finally, the temperature test showed that the composites had excellent cooling property, which was in accordance with solar reflectance result.

  19. Optimization of Cooling Process of Iron Ore Pellets Based on Mathematical Model and Data Mining

    Institute of Scientific and Technical Information of China (English)

    Gui-ming YANG; Xiao-hui FAN; Xu-ling CHEN; Xiao-xian HUANG; Xi LI

    2015-01-01

    Cooling process of iron ore pellets in a circular cooler has great impacts on the pellet quality and systematic energy exploitation. However, multi-variables and non-visualization of this gray system is unfavorable to efifcient production. Thus, the cooling process of iron ore pellets was optimized using mathematical model and data mining techniques. A mathematical model was established and validated by steady-state production data, and the results show that the calculated values coincide very well with the measured values. Based on the proposed model, effects of important process parameters on gas-pellet temperature proifles within the circular cooler were analyzed to better understand the entire cooling process. Two data mining techniques—Associa-tion Rules Induction and Clustering were also applied on the steady-state production data to obtain expertise operating rules and optimized targets. Finally, an optimized control strategy for the circular cooler was proposed and an operation guidance system was developed. The system could realize the visualization of thermal process at steady state and provide operation guidance to optimize the circular cooler.

  20. The Relationship between Emotional Intelligence and Cool and Hot Cognitive Processes: A Systematic Review.

    Science.gov (United States)

    Gutiérrez-Cobo, María José; Cabello, Rosario; Fernández-Berrocal, Pablo

    2016-01-01

    Although emotion and cognition were considered to be separate aspects of the psyche in the past, researchers today have demonstrated the existence of an interplay between the two processes. Emotional intelligence (EI), or the ability to perceive, use, understand, and regulate emotions, is a relatively young concept that attempts to connect both emotion and cognition. While EI has been demonstrated to be positively related to well-being, mental and physical health, and non-aggressive behaviors, little is known about its underlying cognitive processes. The aim of the present study was to systematically review available evidence about the relationship between EI and cognitive processes as measured through "cool" (i.e., not emotionally laden) and "hot" (i.e., emotionally laden) laboratory tasks. We searched Scopus and Medline to find relevant articles in Spanish and English, and divided the studies following two variables: cognitive processes (hot vs. cool) and EI instruments used (performance-based ability test, self-report ability test, and self-report mixed test). We identified 26 eligible studies. The results provide a fair amount of evidence that performance-based ability EI (but not self-report EI tests) is positively related with efficiency in hot cognitive tasks. EI, however, does not appear to be related with cool cognitive tasks: neither through self-reporting nor through performance-based ability instruments. These findings suggest that performance-based ability EI could improve individuals' emotional information processing abilities.

  1. A Generic Framework for Systematic Design of Process Monitoring and Control System for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Meisler, Kresten Troelstrup; Sin, Gürkan

    2012-01-01

    A generic framework for systematic design of a process monitoring and control system for crystallization processes has been developed in order to obtain the desired end-product properties notably the crystal size distribution (CSD). The design framework contains a generic crystallizer modelling...... tool-box, a tool for design of operational policies as well as a tool for design of process monitoring and control systems. Through this framework, it is possible for a wide range of crystallization processes to generate the necessary problem-system specific model, the necessary operational policy...... and a Process Analytical Technology (PAT) system design including implementation of monitoring tools and control strategies in order to produce a desired product with its corresponding target properties. Application of the framework is highlighted through a case study involving the system potassium dihydrogen...

  2. High-frequency thermal processes in harmonic crystals

    CERN Document Server

    Kuzkin, Vitaly A

    2016-01-01

    We consider two high-frequency thermal processes in uniformly heated harmonic crystals relaxing towards equilibrium: (i) equilibration of kinetic and potential energies and (ii) redistribution of energy among spatial directions. Equation describing these processes with deterministic initial conditions is derived. Solution of the equation shows that characteristic time of these processes is of the order of ten periods of atomic vibrations. After that time the system practically reaches the stationary state. It is shown analytically that in harmonic crystals temperature tensor is not isotropic even in the stationary state. As an example, harmonic triangular lattice is considered. Simple formula relating the stationary value of the temperature tensor and initial conditions is derived. The function describing equilibration of kinetic and potential energies is obtained. It is shown that the difference between the energies (Lagrangian) oscillates around zero. Amplitude of these oscillations decays inversely proport...

  3. Ethnography of Cool Roof Retrofits: The Role of Rebates in the Materials Selection Process

    Energy Technology Data Exchange (ETDEWEB)

    Mazur-Stommen, Susan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-02-01

    In the summer of 2010, ethnographic research was conducted with nine households in the Bay Area and Sacramento region. The purpose of this task was to collect methodologically grounded insights into how and why consumers chose the cool roofing material they selected. These nine households comprised fifteen respondents, and their dependents. They were selected from among a pool of respondents to a mail solicitation of all Sacramento Municipal Utility District and Pacific Gas and Electric customers who had received a rebate for their cool roof retrofit. Consumers are uniformly happy with their cool roof retrofits. Consumers typically stayed very close to the aesthetic of the original roof style. Price was not a primary concern, while longevity was paramount. Consumers did not use roofing price, nor energy savings (with one exception), in tracking return on investment through energy savings. The utility rebate had little role to play in terms of incentivizing customers to choose cool materials. Contractors were critical partners in the decision-­making process.

  4. The influence of slow cooling on Y211 size and content in single-grain YBCO bulk superconductor through the infiltration-growth process

    Energy Technology Data Exchange (ETDEWEB)

    Ouerghi, A [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia); Moutalbi, N., E-mail: nahed.moutalbi@yahoo.fr [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia); Noudem, J.G. [CRISMAT-ENSICAEN (UMR-CNRS 6508), Université de Caen-Basse-Normandie, F-14050 Caen (France); LUSAC, Université de Caen-Basse-Normandie F-50130 Cherbourg-Octeville (France); M' chirgui, A. [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia)

    2017-03-15

    Highlights: • YBCO bulk superconductors are produced by optimized Seeded Infiltration and Growth process. • The slow cooling time, in a fixed slow cooling temperature window, affects considerably the surface morphology and the bulk’s microstructure. • The Y211 particle’s size and content depend on the slow cooling time and its distribution behavior changes from one position to another. • There is an optimum slow cooling time, estimated to 88h, over which the shrinkage for both the liquid phase and the Y211 pellet is maximal, without any improvement of the crystal grain growth. • The magnetic trapped flux distribution for a given sample brings out the single grain characteristic. - Abstract: Highly textured YBa{sub 2}Cu{sub 3}O{sub 7-δ} (Y123) superconductors were produced using modified Textured Top Seeded Infiltration Growth (TSIG) process. The liquid source is made of only Y123 powder whereas the solid source is composed of Y{sub 2}BaCuO{sub 5} (Y211) powder. We aim to control the amount of liquid that infiltrates the solid pellet, which in turn controls the final amount of Y{sub 2}BaCuO{sub 5} particles in Y123 matrix. The effect of the slow cooling kinetics on sample morphology, on grain growth and on final microstructure was too investigated. It is shown that appropriate slow cooling time may also contribute to the control of the amount of Y211 inclusions in the final structure of Y123 bulk. We report herein the Y211 particle size and density distribution in the whole Y123 matrix. The present work proves that finest Y211 particles locate under the seed and that their size and density increase with distance from the seed.

  5. A Mathematical Model for Forecasting Distortion of Workpieces with Phase Transformation on Cooling Process

    Institute of Scientific and Technical Information of China (English)

    Jiansong YE; Yikang LIU; Yuanjun ZHOU

    2003-01-01

    A temperature phase transformation stress coupled 3D nonlinear mathematical model has been proposed for forecasting distortion of workpieces on the cooling processes in this paper. Moreover, a series of subroutines were developed on the MARC (analysis research corporation) software platform and the simulation result is basically identical with the experimental one that measured on the workpiece shape with LEITZ equipment. This verifies that the mathematical model and method are feasible.

  6. Elastocaloric cooling processes: The influence of material strain and strain rate on efficiency and temperature span

    Science.gov (United States)

    Schmidt, Marvin; Schütze, Andreas; Seelecke, Stefan

    2016-06-01

    This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.

  7. Elastocaloric cooling processes: The influence of material strain and strain rate on efficiency and temperature span

    Directory of Open Access Journals (Sweden)

    Marvin Schmidt

    2016-06-01

    Full Text Available This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.

  8. Central Data Processing System (CDPS) users manual: solar heating and cooling program

    Energy Technology Data Exchange (ETDEWEB)

    1976-09-01

    The Central Data Processing System (CDPS) provides the software and data base management system required to assess the performance of solar heating and cooling systems installed at multiple remote sites. The instrumentation data associated with these systems is collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. The CDPS consists of three major elements: communication interface computer, central data processing computer, and performance evaluation data base. The CDPS Users Manual identifies users of the performance data base, procedures for operation, and guidelines for software maintenance. The manual also defines the output capabilities of the CDPS in support of external users of the system.

  9. An analytical description of transient thermal processes in harmonic crystals

    Science.gov (United States)

    Kuzkin, V. A.; Krivtsov, A. M.

    2017-05-01

    We consider two transient thermal processes in uniformly heated harmonic crystals: (i) equalibration of kinetic and potential energies and (ii) redistribution of the kinetic energy among the spatial directions. Equations describing these two processes in two-dimensional and three-dimensional crystals are derived. Analytical solutions of these equations for the square and triangular lattices are obtained. It is shown that the characteristic time of the transient processes is of the order of ten periods of atomic vibrations. The difference between the kinetic and potential energies oscillates in time. For the triangular lattice, amplitude of the oscillations decays inversely proportional to time, while for the square lattice it decays inversely proportional to the square root of time. In general, there is no equipartition of the kinetic energy among spatial directions, i.e. the kinetic temperature demonstrates tensor properties. In addition, the covariance of velocities of different particles is nonzero even at the steady state. The analytical results are supported by numerical simulations. It is also shown that the obtained solutions accurately describe the transient thermal processes in weakly nonlinear crystals at short times.

  10. Kinetic Processes Crystal Growth, Diffusion, and Phase Transformations in Materials

    CERN Document Server

    Jackson, Kenneth A

    2004-01-01

    The formation of solids is governed by kinetic processes, which are closely related to the macroscopic behaviour of the resulting materials. With the main focus on ease of understanding, the author begins with the basic processes at the atomic level to illustrate their connections to material properties. Diffusion processes during crystal growth and phase transformations are examined in detail. Since the underlying mathematics are very complex, approximation methods typically used in practice are the prime choice of approach. Apart from metals and alloys, the book places special emphasis on th

  11. Physicochemical properties of dicesium tetravalent plutonium hexanitrate in uranium crystallization process

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, M; Koizumi, T [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan); Nomura, K, E-mail: nakahara.masaumi@jaea.go.jp [Advanced Nuclear System Reserch and Development Directorate, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2010-03-15

    Tetravalent Pu reacts with Cs ions to form the crystalline precipitate of Cs{sub 2}Pu(NO{sub 3}){sub 6}under certain chemical conditions during the U crystallization process. The Cs{sub 2}Pu(NO{sub 3}){sub 6}precipitate reduces the decontamination factor (DF) of Cs to U in the crystal after being washed. The solubility and thermal properties of Cs{sub 2}Pu(NO{sub 3}){sub 6} were studied with the aim of providing a characterization estimate. The solubility of Cs{sub 2}Pu(NO{sub 3}){sub 6} increased with decreases in HNO{sub 3} concentration. Loss in weight of the compound caused by thermal degradation of Cs{sub 2}Pu(NO{sub 3}){sub 6} to Cs{sub 2}PuO{sub 2}(NO{sub 3}){sub 4} was observed at 245 deg. C in thermal analysis. A uranyl nitrate hexahydrate (UNH) crystal was obtained by cooling irradiated fast reactor core fuel dissolver solution. The DF of Cs decreased with increasing the HNO{sub 3} concentration of the mother liquor because more Cs{sub 2}Pu(NO{sub 3}){sub 6} precipitates with high concentration of HNO{sub 3}.

  12. Modelling of Verneuil process for the sapphire crystal growth

    Science.gov (United States)

    Barvinschi, Floricica; Santailler, Jean-Louis; Duffar, Thierry; Le Gal, Hervé

    1999-03-01

    The finite element software FIDAP was used to simulate the Verneuil crystal growth process. The turbulent combustion between hydrogen and oxygen, giving water, the hydrodynamics of the gas phase, the inlet and outlet chemical species flow resulting from the combustion and the heat transfer in the furnace (including internal wall-to-wall radiation) are taken into account. A problem with 10 degrees of freedom per node is generated, solved and the results of the axisymmetric model have shown that the coupling of all these phenomena can be achieved in one numerical model. The effects of transparency of the crystal is discussed. A qualitative agreement between some experimental observations and the model is found, so that modelling may be a good tool for studying the Verneuil process. Nevertheless, some improvements of the model in conjunction with other experimental validations appear necessary.

  13. Thermally driven interaction of the littoral and limnetic zones by autumnal cooling processes

    Directory of Open Access Journals (Sweden)

    Kolumban HUTTER

    2005-02-01

    Full Text Available In autumn, during the transition period, shores influence the interior dynamics of large temperate lakes by the formation of horizontal water-temperature gradients between the shallow and deep areas, whilst vertical temperature gradients are smoothed by convection due to surface cooling. A simple heat budget model, based on the heat balance of the water column without horizontal advection and turbulent mixing, allows deduction of the time-dependent difference between the mean temperature within the littoral area and the temperature in the upper mixed layer. The model corroborates that littoral areas cool faster than regions distant from shores, and provides a basis for an estimation of structure of flows from the beginning of cooling process till the formation of the thermal bar. It predicts the moment in the cooling process, when the corresponding density difference between the littoral and limnetic parts reaches a maximum. For a linear initial vertical temperature profile, the time-dependent "target depth" is explicitly calculated; this is the depth in the pelagic area with a temperature, characteristic of the littoral zone. This depth is estimated as 4/3 of the (concurrent thickness of the upper mixed layer. It is shown that, for a linear initial vertical temperature profile, the horizontal temperature profile between the shore and the lake has a self-similar behavior, and the temperature difference between the littoral waters and the upper mixed off-shore layer, divided by the depth of the upper mixed layer, is an invariant of the studied process. The results are in conformity with field data.

  14. Crystallization behavior during melt-processing of ceramic waste forms

    Science.gov (United States)

    Tumurugoti, Priyatham; Sundaram, S. K.; Misture, Scott T.; Marra, James C.; Amoroso, Jake

    2016-05-01

    Multiphase ceramic waste forms based on natural mineral analogs are of great interest for their high chemical durability, radiation resistance, and thermodynamic stability. Melt-processed ceramic waste forms that leverage existing melter technologies will broaden the available disposal options for high-level nuclear waste. This work reports on the crystallization behavior in selected melt-processed ceramics for waste immobilization. The phase assemblage and evolution of hollandite, zirconolite, pyrochlore, and perovskite type structures during melt processing were studied using thermal analysis, x-ray diffraction, and electron microscopy. Samples prepared by melting followed by annealing and quenching were analyzed to determine and measure the progression of the phase assemblage. Samples were melted at 1500 °C and heat-treated at crystallization temperatures of 1285 °C and 1325 °C corresponding to exothermic events identified from differential scanning calorimetry measurements. Results indicate that the selected multiphase composition partially melts at 1500 °C with hollandite coexisting as crystalline phase. Perovskite and zirconolite phases crystallized from the residual melt at temperatures below 1350 °C. Depending on their respective thermal histories, different quenched samples were found to have different phase assemblages including phases such as perovskite, zirconolite and TiO2.

  15. Large eddy simulations of turbulent flows on graphics processing units: Application to film-cooling flows

    Science.gov (United States)

    Shinn, Aaron F.

    Computational Fluid Dynamics (CFD) simulations can be very computationally expensive, especially for Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS) of turbulent ows. In LES the large, energy containing eddies are resolved by the computational mesh, but the smaller (sub-grid) scales are modeled. In DNS, all scales of turbulence are resolved, including the smallest dissipative (Kolmogorov) scales. Clusters of CPUs have been the standard approach for such simulations, but an emerging approach is the use of Graphics Processing Units (GPUs), which deliver impressive computing performance compared to CPUs. Recently there has been great interest in the scientific computing community to use GPUs for general-purpose computation (such as the numerical solution of PDEs) rather than graphics rendering. To explore the use of GPUs for CFD simulations, an incompressible Navier-Stokes solver was developed for a GPU. This solver is capable of simulating unsteady laminar flows or performing a LES or DNS of turbulent ows. The Navier-Stokes equations are solved via a fractional-step method and are spatially discretized using the finite volume method on a Cartesian mesh. An immersed boundary method based on a ghost cell treatment was developed to handle flow past complex geometries. The implementation of these numerical methods had to suit the architecture of the GPU, which is designed for massive multithreading. The details of this implementation will be described, along with strategies for performance optimization. Validation of the GPU-based solver was performed for fundamental bench-mark problems, and a performance assessment indicated that the solver was over an order-of-magnitude faster compared to a CPU. The GPU-based Navier-Stokes solver was used to study film-cooling flows via Large Eddy Simulation. In modern gas turbine engines, the film-cooling method is used to protect turbine blades from hot combustion gases. Therefore, understanding the physics of

  16. Testing of heating and cooling process of ADI cast iron with use of ATND method

    Directory of Open Access Journals (Sweden)

    A. Białobrzeski

    2008-10-01

    Full Text Available ADI (Austempered Ductile Iron cast iron, owing to its unique combination of high tensile strength and abrasion resistance with very goodplasticity, founds implementation in many branches of industry as a substitute of alloy cast steel and carburized or heat treated steels. Inspite of its solid position among producers and recipients of castings, there are still undertaken studies aimed at perfection of its propertiesand recognition of mechanisms enabling obtaining such properties.The paper presents implementation of thermal-voltage-derivative (ATND method to registration of heating and cooling course of ADIcast iron with EN-GJS-1200-2 grade. ADI cast iron with EN-GJS-1200-2 grade underwent the study. Heat treatment of the cast iron wasperformed in Foundry Institute with use of LT ADI-350/1000 processing line. Results obtained from the testing illustrate in graphic formregistered heating and cooling curves of investigated cast irons obtained with use of the ATND method.

  17. Relaxation transition due to different cooling processes in a superconducting levitation system

    Science.gov (United States)

    Zhou, You-He; Zhang, Xing-Yi; Zhou, Jun

    2008-06-01

    We present an experimental study of relaxation of vertical and horizontal force components in a high-temperature superconducting levitation system, with different initial cooling process after fixing the levitated body in an expected position statically. In the experiment, the bulk YBaCuO cylinder superconductor and the permanent magnet disk are employed. For a selected levitation height (LH) and a lateral displacement (LD) of the system, the experimental results show that the relaxations of the vertical and horizontal forces are strongly dependent on the initial cooling height (CH). With CH decreasing, the transition of the lateral force from repulsion to attraction is found as well as the changing characteristics with time from decrease to increase. Additionally, when LH is fixed at the CH, the transition phenomenon is also observed in the levitation force behavior and their relaxation under different LDs.

  18. Liquid Crystals of Dendron-Like Pt Complexes Processable Into Nanofilms Dendrimers. Phase 2. Cholesteric Liquid Crystal Glass Platinum Acetylides

    Science.gov (United States)

    2014-08-01

    ciqa.edu.mx AFOSR FA9550-12-1-0234 August 2014 Cholesteric liquid crystal glass platinum acetylides Eduardo Arias...to be vitrified on cooling and form long time stability cholesteric glasses at room temperature, a series of platinum acetylide complexes modified...OCH3 and F, the cholesteric pitch was determined to be 1.7, 3.4 and 9.0 µ, respectively. INTRODUCTION Platinum acetylides are nonlinear

  19. Effects of micro electric current load during cooling of plant tissues on intracellular ice crystal formation behavior and pH.

    Science.gov (United States)

    Ninagawa, Takako; Kawamura, Yukio; Konishi, Tadashi; Narumi, Akira

    2016-08-01

    Cryopreservation techniques are expected to evolve further to preserve biomaterials and foods in a fresh state for extended periods of time. Long-term cryopreservation of living materials such as food and biological tissue is generally achieved by freezing; thus, intracellular freezing occurs. Intracellular freezing injures the cells and leads to cell death. Therefore, a dream cryopreservation technique would preserve the living materials without internal ice crystal formation at a temperature low enough to prevent bacterial activity. This study was performed to investigate the effect of micro electrical current loading during cooling as a new cryopreservation technique. The behavior of intracellular ice crystal formation in plant tissues with or without an electric current load was evaluated using the degree of supercooling, degree of cell deformation, and grain size and growing rate of intracellular ice crystal. Moreover, the transition of intracellular pH during plant tissue cooling with or without electric current loading was also examined using the fluorescence intensity ratio to comprehend cell activity at lower temperatures. The results indicated that micro electric current load did not only decrease the degree of cell deformation and grain size of intracellular ice crystal but also reduced the decline in intracellular pH due to temperature lowering, compared with tissues subjected to the same cooling rate without an electric current load. Thus, the effect of electric current load on cryopreservation and the potential of a new cryopreservation technique using electric current load were discussed based on these results.

  20. Mathematical model for the thermal process of controlled cooling of wires and its numerical simulation

    Institute of Scientific and Technical Information of China (English)

    Hongxiang Zhu; Xiaohong Hao; Zhi Wen; Yaogen Zhang; Huqiu Chen

    2004-01-01

    The mathematical model for the thermal process of billets rolling has been established, including transporting in air and temperature-holding cover, descaling with high-pressure water, and the process of rolling and cooling in water box. The calculated data by the model have been compared with the measured data and the results show that the model is right and creditable. Based on the model, the main thermal characters of rolling line have been simulated and the influence of all the parameters on the temperature of rolling has been analyzed.

  1. Relationship between crystallization tendencies during cooling from melt and isothermal storage: toward a general understanding of physical stability of pharmaceutical glasses.

    Science.gov (United States)

    Kawakami, Kohsaku; Harada, Takuji; Miura, Keiko; Yoshihashi, Yasuo; Yonemochi, Etsuo; Terada, Katsuhide; Moriyama, Hiroshi

    2014-06-02

    The lack of protocols to predict the physical stability has been one of the most important issues in the use of amorphous solid dispersions. In this paper, the crystallization behaviors of pharmaceutical glasses, which have large variations in their crystallization tendencies, have been investigated. Although each compound appears to have a wide variation in their crystallization time, the initiation time for crystallization could be generalized as a function of only Tg/T, where Tg and T are the glass transition temperature and storage temperature, respectively. All compounds in which crystallization was mainly governed by temperature had similar activation energies for crystallization initiation, ca. 210-250 kJ/mol, indicating that physical stability at any temperature is predictable from only Tg. Increased stability is expected for other compounds, where crystallization is inhibited by an large energetic barrier, and stochastic nucleation plays an important role in initiating crystallization. The difference in the dominant factor, either temperature or pressure, appeared to correlate with the nucleation mechanism, and this could be determined by a cool-heat cycle after melting using thermal analysis. This conclusion should make prediction of physical stability of amorphous formulations easier, although the investigation was conducted under ideal conditions, which eliminated surface effects.

  2. The Relationship between Emotional Intelligence and Cool and Hot Cognitive Processes: A Systematic Review

    Science.gov (United States)

    Gutiérrez-Cobo, María José; Cabello, Rosario; Fernández-Berrocal, Pablo

    2016-01-01

    Although emotion and cognition were considered to be separate aspects of the psyche in the past, researchers today have demonstrated the existence of an interplay between the two processes. Emotional intelligence (EI), or the ability to perceive, use, understand, and regulate emotions, is a relatively young concept that attempts to connect both emotion and cognition. While EI has been demonstrated to be positively related to well-being, mental and physical health, and non-aggressive behaviors, little is known about its underlying cognitive processes. The aim of the present study was to systematically review available evidence about the relationship between EI and cognitive processes as measured through “cool” (i.e., not emotionally laden) and “hot” (i.e., emotionally laden) laboratory tasks. We searched Scopus and Medline to find relevant articles in Spanish and English, and divided the studies following two variables: cognitive processes (hot vs. cool) and EI instruments used (performance-based ability test, self-report ability test, and self-report mixed test). We identified 26 eligible studies. The results provide a fair amount of evidence that performance-based ability EI (but not self-report EI tests) is positively related with efficiency in hot cognitive tasks. EI, however, does not appear to be related with cool cognitive tasks: neither through self-reporting nor through performance-based ability instruments. These findings suggest that performance-based ability EI could improve individuals’ emotional information processing abilities. PMID:27303277

  3. Afterheat usage from cooling facilities in ORC processes; Abwaermenutzung aus Kaelteanlagen in ORC-Prozessen

    Energy Technology Data Exchange (ETDEWEB)

    Theede, Florian; Luke, Andrea [Kassel Univ. (Germany). Technische Themodynamik

    2016-07-01

    In the course of the reduction of climate warming an energy-efficient lay-out of processes is necessary. A possibility for the efficiency increasement is the usage of afterheat currents for instance in ORC processes. Connected with the limitation of refrigerants with high greenhouse potential it comes to the increased application of transcritical cooling facilities with carbon dioxide (CO{sub 2}) as refrigerant. By the high pressures after the compression arise here new afterheat sources on a temperature level of about 100 C. An alternative for the simple back-cooling or the heating support and drinking-water heating represents the current production in an ORC process. Great challenges for the lay-out of such an ORC process are the selection of the working fluid as well as the lay-out of the heat exchangers. Established refrigerants in the low-temperature like R245fa for ORC facilities will be in forseeable future no more available. For the study of the possible replacement by alternative refrigerants a simulation model has been developed. By means of this model different refrigerants are analyzed regarding their performance and simultaneously the effects on process and other components studied. The results show that in the temperature range two hydrofluoroolefines R1233zd[E] and R1234ze[Z] as well as the hadron carbon butane can thermodynamically form an alternative.

  4. Crystal Sinking Modeling for Designing Iodine Crystallizer in Thermochemical Sulfur-Iodine Hydrogen Production Process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byung Heung [Korea National University of Transportation, Chungju (Korea, Republic of); Jeong, Seong-Uk [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Kang, Jeong Won [Korea University, Seoul (Korea, Republic of)

    2014-12-15

    SI process is a thermochemical process producing hydrogen by decomposing water while recycling sulfur and iodine. Various technologies have been developed to improve the efficiency on Section III of SI process, where iodine is separated and recycled. EED(electro-electrodialysis) could increase the efficiency of Section III without additional chemical compounds but a substantial amount of I{sub 2} from a process stream is loaded on EED. In order to reduce the load, a crystallization technology prior to EED is considered as an I{sub 2} removal process. In this work, I{sub 2} particle sinking behavior was modeled to secure basic data for designing an I{sub 2} crystallizer applied to I{sub 2}-saturated HI{sub x} solutions. The composition of HI{sub x} solution was determined by thermodynamic UVa model and correlation equations and pure properties were used to evaluate the solution properties. A multiphysics computational tool was utilized to calculate particle sinking velocity changes with respect to I{sub 2} particle radius and temperature. The terminal velocity of an I{sub 2} particle was estimated around 0.5 m/s under considered radius (1.0 to 2.5 mm) and temperature (10 to 50 .deg. C) ranges and it was analyzed that the velocity is more dependent on the solution density than the solution viscosity.

  5. SIMULATION TOOL OF VELOCITY AND TEMPERATURE PROFILES IN THE ACCELERATED COOLING PROCESS OF HEAVY PLATES

    Directory of Open Access Journals (Sweden)

    Antônio Adel dos Santos

    2014-10-01

    Full Text Available The aim of this paper was to develop and apply mathematical models for determining the velocity and temperature profiles of heavy plates processed by accelerated cooling at Usiminas’ Plate Mill in Ipatinga. The development was based on the mathematical/numerical representation of physical phenomena occurring in the processing line. Production data from 3334 plates processed in the Plate Mill were used for validating the models. A user-friendly simulation tool was developed within the Visual Basic framework, taking into account all steel grades produced, the configuration parameters of the production line and these models. With the aid of this tool the thermal profile through the plate thickness for any steel grade and dimensions can be generated, which allows the tuning of online process control models. The simulation tool has been very useful for the development of new steel grades, since the process variables can be related to the thermal profile, which affects the mechanical properties of the steels.

  6. Comparison between two rheocasting processes of damper cooling tube method and low superheat casting

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaoli; Ling Xiangjun; Wang Tongmin; Li Tingju

    2014-01-01

    To produce a high quality semisolid slurry that consists of fine primary particles uniformly suspended in the liquid matrix for rheoforming, chemical refining and electromagnetic or mechanical stirring are the two methods commonly used. But these two methods either contaminate the melt or incur high cost. In this study, the damper cooling tube (DCT) method was designed to prepare semisolid slurry of A356 aluminum alloy, and was compared with the low superheat casting (LSC) method - a conventional process used to produce casting slab with equiaxed dendrite microstructure for thixoforming route. A series of comparative experiments were performed at the pouring temperatures of 650 °C, 638 °C and 622 °C. Metal ographic observations of the casting samples were carried out using an optical electron microscope with image analysis software. Results show that the microstructure of semisolid slurry produced by the DCT process consists of spherical primary α-Al grains, while equiaxed grains microstructure is found in the LSC process. The lower the pouring temperature, the smal er the grain size and the rounder the grain morphology in both methods. The copious nucleation, which could be generated in the DCT, owing to the cooling and stirring effect, is the key to producing high quality semisolid slurry. DCT method could produce rounder and smal er α-Al grains, which are suitable for semisolid processing; and the equivalent grain size is no more than 60 µm when the pouring temperature is 622 °C.

  7. Comparison between two rheocasting processes of damper cooling tube method and low superheat casting

    Directory of Open Access Journals (Sweden)

    Zhang Xiaoli

    2014-09-01

    Full Text Available To produce a high quality semisolid slurry that consists of fine primary particles uniformly suspended in the liquid matrix for rheoforming, chemical refining and electromagnetic or mechanical stirring are the two methods commonly used. But these two methods either contaminate the melt or incur high cost. In this study, the damper cooling tube (DCT method was designed to prepare semisolid slurry of A356 aluminum alloy, and was compared with the low superheat casting (LSC method - a conventional process used to produce casting slab with equiaxed dendrite microstructure for thixoforming route. A series of comparative experiments were performed at the pouring temperatures of 650 °C, 638 °C and 622 °C. Metallographic observations of the casting samples were carried out using an optical electron microscope with image analysis software. Results show that the microstructure of semisolid slurry produced by the DCT process consists of spherical primary α-Al grains, while equiaxed grains microstructure is found in the LSC process. The lower the pouring temperature, the smaller the grain size and the rounder the grain morphology in both methods. The copious nucleation, which could be generated in the DCT, owing to the cooling and stirring effect, is the key to producing high quality semisolid slurry. DCT method could produce rounder and smaller α-Al grains, which are suitable for semisolid processing; and the equivalent grain size is no more than 60 μm when the pouring temperature is 622 °C.

  8. Real-time measurements of crystallization processes in viscoelastic polymeric photonic crystals.

    Science.gov (United States)

    Snoswell, David R E; Finlayson, Chris E; Zhao, Qibin; Baumberg, Jeremy J

    2015-11-01

    We present a study of the dynamic shear ordering of viscoelastic photonic crystals, based on core-shell polymeric composite particles. Using an adapted shear-cell arrangement, the crystalline ordering of the material under conditions of oscillatory shear is interrogated in real time, through both video imaging and from the optical transmission spectra of the cell. In order to gain a deeper understanding of the macroscopic influences of shear on the crystallization process in this solvent-free system, the development of bulk ordering is studied as a function of the key parameters including duty cycle and shear-strain magnitude. In particular, optimal ordering is observed from a prerandomized sample at shear strains of around 160%, for 1-Hz oscillations. This ordering reaches completion over time scales of order 10 s. These observations suggest significant local strains are needed to drive nanoparticles through energy barriers, and that local creep is needed to break temporal symmetry in such high-viscosity nanoassemblies. Crystal shear-melting effects are also characterized under conditions of constant shear rate. These quantitative experiments aim to stimulate the development of theoretical models which can deal with the strong local particle interactions in this system.

  9. Process development for single-crystal silicon solar cells

    Science.gov (United States)

    Bohra, Mihir H.

    Solar energy is a viable, rapidly growing and an important renewable alternative to other sources of energy generation because of its abundant supply and low manufacturing cost. Silicon still remains the major contributor for manufacturing solar cells accounting for 80% of the market share. Of this, single-crystal solar cells account for half of the share. Laboratory cells have demonstrated 25% efficiency; however, commercial cells have efficiencies of 16% - 20% resulting from a focus on implementation processes geared to rapid throughput and low cost, thereby reducing the energy pay-back time. An example would be the use of metal pastes which dissolve the dielectric during the firing process as opposed to lithographically defined contacts. With current trends of single-crystal silicon photovoltaic (PV) module prices down to 0.60/W, almost all other PV technologies are challenged to remain cost competitive. This presents a unique opportunity in revisiting the PV cell fabrication process and incorporating moderately more expensive IC process practices into PV manufacturing. While they may drive the cost toward a 1/W benchmark, there is substantial room to "experiment", leading to higher efficiencies which will help maintain the overall system cost. This work entails a turn-key process designed to provide a platform for rapid evaluation of novel materials and processes. A two-step lithographic process yielding a baseline 11% - 13% efficient cell is described. Results of three studies have shown improvements in solar cell output parameters due to the inclusion of a back-surface field implant, a higher emitter doping and also an additional RCA Clean.

  10. Finite element modeling of cooled-tip probe radiofrequency ablation processes in liver tissue.

    Science.gov (United States)

    Barauskas, Rimantas; Gulbinas, Antanas; Vanagas, Tomas; Barauskas, Giedrius

    2008-06-01

    Finite element model of radiofrequency ablation (RFA) with cooled-tip probe in liver has been developed by employing COMSOL Multiphysics software. It describes coupled electric, thermal and sodium chloride solution infiltration flow phenomena taking place during ablation processes. Features of hydraulic capacity, saturation of the tissue by infiltration, and dependency of electrical conductivity on the damage integral of the tissue have been supplied to the model. RFA experiments have validated the model. Physical parameters describing hydraulic capacity and hydraulic conductivity in the tissue, as well as, the relation of electrical conductivity against the value of damage integral have been determined.

  11. Molecular Dynamics Simulation Studies on the Cooling Process of Polyvinyl Chloride

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    By means of molecular dynamics simulation, the transition of the conformations of polyvinyl chloride during a cooling process from 600 to 300 K was studied. The results show that the amorphous polyvinyl chloride chain experiences the melting state, elastic state and glass state and the conformations can be characterized by the increases of the trans-state of C-C-C-C and the near gauche-state of C-C-C-Cl with the decrease of temperature. It is found that the transition of the conformations is driven mainly by the Coulomb interaction between chain segments.

  12. Cu-Zn slags from Røros (Norway): a case study of rapid cooling and crystal nucleation

    Science.gov (United States)

    Warchulski, Rafał; Szopa, Krzysztof

    2014-09-01

    The mining town of Røros located in central Norway was established in 1644 and it is known of historical mining industry related to copper. Røros was designated as an UNESCO World Heritage Site in 1980 on the base of mining culture represented by, e.g., unique wooden architecture. Slag pieces are composed of three parts differing in glass to crystallites ratio. Røros slags are composed of olivine- and pyroxene- group minerals accompanied by sulphides, with glass in the interstices. Temperature gradient and volatiles content were determined as the main factor influencing crystallization process in this material

  13. Cu-Zn Slags from R⊘ros (Norway): A Case Study of Rapid Cooling and Crystal Nucleation

    Science.gov (United States)

    Warchulski, Rafał; Szopa, Krzysztof

    2014-09-01

    The mining town of R⊘ros located in central Norway was established in 1644 and it is known of historical mining industry related to copper. R⊘ros was designated as an UNESCO World Heritage Site in 1980 on the base of mining culture represented by, e.g., unique wooden architecture. Slag pieces are composed of three parts differing in glass to crystallites ratio. R⊘ros slags are composed of olivine- and pyroxene- group minerals accompanied by sulphides, with glass in the interstices. Temperature gradient and volatiles content were determined as the main factor influencing crystallization process in this material.

  14. Materials processing threshold report. 1: Semiconductor crystals for infrared detectors

    Science.gov (United States)

    Sager, E. V.; Thompson, T. R.; Nagler, R. G.

    1980-01-01

    An extensive search was performed of the open literature pertaining to infrared detectors to determine what constitutes a good detector and in what way performance is limited by specific material properties. Interviews were conducted with a number of experts in the field to assess their perceptions of the state of the art and of the utility of zero-gravity processing. Based on this information base and on a review of NASA programs in crystal growth and infrared sensors, NASA program goals were reassessed and suggestions are presented as to possible joint and divergent efforts between NASA and DOD.

  15. Continuous Cooling Bainite Transformation Characteristics of a Low Carbon Microalloyed Steel under the Simulated Welding Thermal Cycle Process

    Institute of Scientific and Technical Information of China (English)

    Xiangwei Kong; Chunlin Qiu

    2013-01-01

    Continuous cooling transformation of a low carbon microalloyed steel was investigated after it was subjected to the simulation welding thermal cycle process and the interrupted cooling test.Microstructure observation was performed by optical microscopy and transmission electron microscopy.On the basis of the dilatometric data and microstructure observation,the continuous cooling transformation (CCT) diagram was determined,which showed that the main microstructure changes from a mixture of lath martensite and bainitic ferrite to full granular bainite with the increase in the cooling time t8/5 from 10 to 600 s,accompanied with a decrease in the microhardness.The interrupted cooling test confirmed that the bainitic ferrite can form attached to grain boundaries at the beginning of transformation even if the final microstructure contains a mixture of granular bainite and bainitic ferrite.

  16. Cooling and heating of crystalline ion beams

    CERN Document Server

    Schramm, U; Bussmann, M; Habs, D

    2003-01-01

    The crystallization of ion beams has recently been established in the rf quadrupole storage ring PALLAS (PAul Laser CooLing Acceleration System) for laser-cooled sup 2 sup 4 Mg sup + ion beams at an energy of about 1 eV. Yet, unexpectedly sharp constraints had to be met concerning the confinement strength and the longitudinal laser cooling rate. In this paper, related and up to now unseen heating mechanisms are pinpointed for crystalline beams. The weak but inevitable diffusive transverse heating associated with the laser cooling process itself is investigated, possibly allowing the future measurement of the latent heat of the ion crystal. As a function of the beam velocity, the influence of bending shear on the attainability of larger crystalline structures is presented. Finally, rf heating of crystalline beams of different structure is studied for discontinuous cooling.

  17. Heat Transfer Modeling of an Annular On-Line Spray Water Cooling Process for Electric-Resistance-Welded Steel Pipe.

    Science.gov (United States)

    Chen, Zejun; Han, Huiquan; Ren, Wei; Huang, Guangjie

    2015-01-01

    On-line spray water cooling (OSWC) of electric-resistance-welded (ERW) steel pipes can replace the conventional off-line heat treatment process and become an important and critical procedure. The OSWC process improves production efficiency, decreases costs, and enhances the mechanical properties of ERW steel pipe, especially the impact properties of the weld joint. In this paper, an annular OSWC process is investigated based on an experimental simulation platform that can obtain precise real-time measurements of the temperature of the pipe, the water pressure and flux, etc. The effects of the modes of annular spray water cooling and related cooling parameters on the mechanical properties of the pipe are investigated. The temperature evolutions of the inner and outer walls of the pipe are measured during the spray water cooling process, and the uniformity of mechanical properties along the circumferential and longitudinal directions is investigated. A heat transfer coefficient model of spray water cooling is developed based on measured temperature data in conjunction with simulation using the finite element method. Industrial tests prove the validity of the heat transfer model of a steel pipe undergoing spray water cooling. The research results can provide a basis for the industrial application of the OSWC process in the production of ERW steel pipes.

  18. Heat Transfer Modeling of an Annular On-Line Spray Water Cooling Process for Electric-Resistance-Welded Steel Pipe

    Science.gov (United States)

    Chen, Zejun; Han, Huiquan; Ren, Wei; Huang, Guangjie

    2015-01-01

    On-line spray water cooling (OSWC) of electric-resistance-welded (ERW) steel pipes can replace the conventional off-line heat treatment process and become an important and critical procedure. The OSWC process improves production efficiency, decreases costs, and enhances the mechanical properties of ERW steel pipe, especially the impact properties of the weld joint. In this paper, an annular OSWC process is investigated based on an experimental simulation platform that can obtain precise real-time measurements of the temperature of the pipe, the water pressure and flux, etc. The effects of the modes of annular spray water cooling and related cooling parameters on the mechanical properties of the pipe are investigated. The temperature evolutions of the inner and outer walls of the pipe are measured during the spray water cooling process, and the uniformity of mechanical properties along the circumferential and longitudinal directions is investigated. A heat transfer coefficient model of spray water cooling is developed based on measured temperature data in conjunction with simulation using the finite element method. Industrial tests prove the validity of the heat transfer model of a steel pipe undergoing spray water cooling. The research results can provide a basis for the industrial application of the OSWC process in the production of ERW steel pipes. PMID:26201073

  19. Towards a physical understanding of stratospheric cooling under global warming through a process-based decomposition method

    Science.gov (United States)

    Yang, Yang; Ren, R.-C.; Cai, Ming

    2016-12-01

    The stratosphere has been cooling under global warming, the causes of which are not yet well understood. This study applied a process-based decomposition method (CFRAM; Coupled Surface-Atmosphere Climate Feedback Response Analysis Method) to the simulation results of a Coupled Model Intercomparison Project, phase 5 (CMIP5) model (CCSM4; Community Climate System Model, version 4), to demonstrate the responsible radiative and non-radiative processes involved in the stratospheric cooling. By focusing on the long-term stratospheric temperature changes between the "historical run" and the 8.5 W m-2 Representative Concentration Pathway (RCP8.5) scenario, this study demonstrates that the changes of radiative radiation due to CO2, ozone and water vapor are the main divers of stratospheric cooling in both winter and summer. They contribute to the cooling changes by reducing the net radiative energy (mainly downward radiation) received by the stratospheric layer. In terms of the global average, their contributions are around -5, -1.5, and -1 K, respectively. However, the observed stratospheric cooling is much weaker than the cooling by radiative processes. It is because changes in atmospheric dynamic processes act to strongly mitigate the radiative cooling by yielding a roughly 4 K warming on the global average base. In particular, the much stronger/weaker dynamic warming in the northern/southern winter extratropics is associated with an increase of the planetary-wave activity in the northern winter, but a slight decrease in the southern winter hemisphere, under global warming. More importantly, although radiative processes dominate the stratospheric cooling, the spatial patterns are largely determined by the non-radiative effects of dynamic processes.

  20. The contrasting roles of creep and stress relaxation in the time-dependent deformation during in-situ cooling of a nickel-base single crystal superalloy.

    Science.gov (United States)

    Panwisawas, Chinnapat; D'Souza, Neil; Collins, David M; Bhowmik, Ayan

    2017-09-11

    Time dependent plastic deformation in a single crystal nickel-base superalloy during cooling from casting relevant temperatures has been studied using a combination of in-situ neutron diffraction, transmission electron microscopy and modelling. Visco-plastic deformation during cooling was found to be dependent on the stress and constraints imposed to component contraction during cooling, which mechanistically comprises creep and stress relaxation. Creep results in progressive work hardening with dislocations shearing the γ' precipitates, a high dislocation density in the γ channels and near the γ/γ' interface and precipitate shearing. When macroscopic contraction is restricted, relaxation dominates. This leads to work softening from a decreased dislocation density and the presence of long segment stacking faults in γ phase. Changes in lattice strains occur to a similar magnitude in both the γ and γ' phases during stress relaxation, while in creep there is no clear monotonic trend in lattice strain in the γ phase, but only a marginal increase in the γ' precipitates. Using a visco-plastic law derived from in-situ experiments, the experimentally measured and calculated stresses during cooling show a good agreement when creep predominates. However, when stress relaxation dominates accounting for the decrease in dislocation density during cooling is essential.

  1. A Mechanism of crystallization process of hemoglobin S

    Directory of Open Access Journals (Sweden)

    Carlos Cabal-Mirabal

    2008-01-01

    Full Text Available It has been studied as the qualitative consequence of a proposed mechanism of reaction for the formation of HbS molecular aggregations, as well as the mathematical model associated with it, for the particular case that the process of crystallization takes place at partial pressure and constant temperature. It is showed that the results mentioned in the study can be used to explain experimental existing data, although this data are small to decide between various options that are compatible with existing experimental models and experimental data. Also, qualitative consequences of to mechanism of reaction suggested for the formation of HbS molecular aggregations, as well as the mathematical model associated, are studied for a particular case in which to process of crystallization under constant oxygen, partial pressure and constant tem- peratures. The results of such study, which are able to explain the existing experi- mental data, are shown. However, this is latter very scarce for being able to decide among various existing choices compatible with the model and experimental data.

  2. Dynamic process of trace boron non-equilibrium grain boundary segregation and the effect of cooling rate

    Institute of Scientific and Technical Information of China (English)

    Ping Wu; Xinlai He; Bing Cao; Sen Chen

    2003-01-01

    The dynamic process of non-equilibrium grain boundary segregation of trace boron in Fe-40%Ni alloy during cooling andthe effect of cooling rate were investigated by boron tracking autoradiography technique. The results indicate that during coolingprocess, the amount of segregated boron on grain boundary firstly increases fast, then enters a comparatively even increasing stageand increases rapidly again at the third stage. The details of each stage varied with cooling rate are explained. When thc segregationdevelops to a certain degree, the segregated boron atoms transform fiom solute status to precipitate status.

  3. Advanced CD-SEM metrology for qualification of DSA patterns using coordinated line epitaxy (COOL) process

    Science.gov (United States)

    Kato, Takeshi; Konishi, Junko; Ikota, Masami; Yamaguchi, Satoru; Seino, Yuriko; Sato, Hironobu; Kasahara, Yusuke; Azuma, Tsukasa

    2016-03-01

    Directed self-assembly (DSA) applying chemical epitaxy is one of the promising lithographic solutions for next generation semiconductor device manufacturing. Especially, DSA lithography using coordinated line epitaxy (COOL) process is obviously one of candidates which could be the first generation of DSA applying PS-b-PMMA block copolymer (BCP) for sub-15nm dense line patterning . DSA can enhance the pitch resolutions, and can mitigate CD errors to the values much smaller than those of the originally exposed guiding patterns. On the other hand, local line placement error often results in a worse value, with distinctive trends depending on the process conditions. To address this issue, we introduce an enhanced measurement technology of DSA line patterns with distinguishing their locations in order to evaluate nature of edge placement and roughness corresponding to individual pattern locations by using images of CD-SEM. Additionally correlations among edge roughness of each line and each space are evaluated and discussed. This method can visualize features of complicated roughness easily to control COOL process. As a result, we found the followings. (1) Line placement error and line placement roughness of DSA were slightly different each other depending on their relative position to the chemical guide patterns. (2) In middle frequency area of PSD (Power Spectral Density) analysis graphs, it was observed that shapes were sensitively changed by process conditions of chemical stripe guide size and anneals temperature. (3) Correlation coefficient analysis using PSD was able to clarify characteristics of latent defect corresponding to physical and chemical property of BCP materials.

  4. Assessment of the reduced ore cooling process at the Ernesto Che Guevara Plant

    Directory of Open Access Journals (Sweden)

    Ever Góngora-Leyva

    2012-10-01

    Full Text Available The analysis of the investigations related to evaluations on the process of reduced ore cooling in rotating horizontal cylinders on an industrial scale indicated that there are only water temperature measurements on one end of pit and showed no experiments where the variables of water and ore flowrates were evaluated nor the relation with the temperature of the ore at the cooler outlet. Based on this precedent, six thermocouples were installed to calculate the cooling water temperature in three locations on both sides of the pit connected to the data input system in place in the enterprise. The design of the experiment was developed from analyzing a population of data from a 6/month period. The results showed that the variable of greater impact on the ore temperature at the cot oler outlet is the water flowrate. For lower water flowrates (15m3/h heat transfer by water evaporation to the air is predominant and for higher water flowrates (25m3/h heat transfer by convection is predominant. Also, it was possible to know that the cooler heat output reaches the highest values (86% with the lowest ore and water flowrates (15m3/h and 29t/h, respectively.

  5. Chiral Symmetry Breaking During Growing Process of NaClO3 Crystal under Direct-Current Electric Field

    Institute of Scientific and Technical Information of China (English)

    CHEN Wan-Chun; CHEN Xiao-Long

    2007-01-01

    @@ We investigate the influence of dc electric field on chiral symmetry breaking during the growing process of NaClO3 crystal. Nucleation and growth of NaClO3 are completed from an aqueous solution by a fast cooling temperature technology. A pair of polarization microscopes are used to identify a distribution of chiral crystals. Experimental results indicate that the dc electric field has an effect on distribution of chirality, but the direction of the dc electric field is not sensitive to the chiral autocatalysis and selectivity, i.e. the nature convection driving by the gravity does not play an important role on a thin layer of NaClO3 solution. The experimental phenomena may be elucidated by the ECSN mechanism.

  6. EXTERNAL ACTION EFFECT ON THE STRUCTURE OF THE LIQUID PHASE, THE CRYSTALLIZATION PROCESS, STRUCTURE FORMATION OF COPPER

    Directory of Open Access Journals (Sweden)

    Mr. Eduard A. Dmitriev

    2016-09-01

    Full Text Available The paper presents the research results of a fluid phase overheating and alloying effect on cuprum mechanical characteristics. Careful analysis of poly-thermal cross-sections of electro-resistance proved that in order to obtain the maximum values of cuprum mechanical properties, it should be overheated 30 °С above the temperature threshold of abnormal electro-resistance change of a fluid phase (1320 °С. The paper presents the research results of the influence of thermal and thermo-high-speed treatment of cuprum melting on its structure, crystallization and structure formation processes. Regularities of structure change, crystallization parameters and structure formation depending on overheating and cooling rate of the melt are stated.

  7. The use of quasi-isothermal modulated temperature differential scanning calorimetry for the characterization of slow crystallization processes in lipid-based solid self-emulsifying systems.

    Science.gov (United States)

    Otun, Sarah O; Meehan, Elizabeth; Qi, Sheng; Craig, Duncan Q M

    2015-04-01

    Slow or incomplete crystallization may be a significant manufacturing issue for solid lipid-based dosage forms, yet little information is available on this phenomenon. In this investigation we suggest a novel means by which slow solidification may be monitored in Gelucire 44/14 using quasi-isothermal modulated temperature DSC (QiMTDSC). Conventional linear heating and cooling DSC methods were employed, along with hot stage microscopy (HSM), for basic thermal profiling of Gelucire 44/14. QiMTDSC experiments were performed on cooling from the melt, using a range of incremental decreases in temperature and isothermal measurement periods. DSC and HSM highlighted the main (primary) crystallization transition; solid fat content analysis and kinetic analysis were used to profile the solidification process. The heat capacity profile from QiMTDSC indicated that after an initial energetic primary crystallisation, the lipid underwent a slower period of crystallization which continued to manifest at much lower temperatures than indicated by standard DSC. We present evidence that Gelucire 44/14 undergoes an initial crystallization followed by a secondary, slower process. QIMTDSC appears to be a promising tool in the investigation of this secondary crystallization process.

  8. Influence of Crucible Thermal Conductivity on Crystal Growth in an Industrial Directional Solidification Process for Silicon Ingots

    Directory of Open Access Journals (Sweden)

    Zaoyang Li

    2016-01-01

    Full Text Available We carried out transient global simulations of heating, melting, growing, annealing, and cooling stages for an industrial directional solidification (DS process for silicon ingots. The crucible thermal conductivity is varied in a reasonable range to investigate its influence on the global heat transfer and silicon crystal growth. It is found that the crucible plays an important role in heat transfer, and therefore its thermal conductivity can influence the crystal growth significantly in the entire DS process. Increasing the crucible thermal conductivity can shorten the time for melting of silicon feedstock and growing of silicon crystal significantly, and therefore large thermal conductivity is helpful in saving both production time and power energy. However, the high temperature gradient in the silicon ingots and the locally concave melt-crystal interface shape for large crucible thermal conductivity indicate that high thermal stress and dislocation propagation are likely to occur during both growing and annealing stages. Based on the numerical simulations, some discussions on designing and choosing the crucible thermal conductivity are presented.

  9. A time-resolved x-ray scattering experiment for the study of phase transitions and crystallization processes in metallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, J. F.; Sutton, M.; Altounian, Z.; Saini, S.; Luriom L. B.; Sandy, A. R.; Lumma, D.; Borthwick, M. A.; Falus, P.; Mochrie, S. G. J.; Stephenson, G. B.

    1999-10-29

    An experimental setup to perform high-resolution time-resolved X-ray scattering has been commissioned on the side station of beamline 8-ID at the Advanced Photon Source. A Peltier-cooled diode detector array covering an angle range of 20 degrees is mounted on a 4-circle goniometer and is used to temporally resolve X-ray scattering patterns with a resolution up to 10 ms. Metallic ribbon samples can be quickly heated and cooled from temperatures up to 500 C inside a furnace with controllable atmosphere and equipped with a beryllium window. A description of the setup is presented along with actual results showing time-resolved phase transitions and crystallization processes in AlYNi metallic alloys. These results demonstrate the power of this technique to investigate complex crystallization processes as well as the versatility of this time-resolved X-ray scattering spectrometer.

  10. Processing of Photonic Crystal Nanocavity for Quantum Information in Diamond

    CERN Document Server

    Bayn, Igal; Lahav, Alex; Salzman, Joseph; Kalish, Rafi; Fairchild, Barbara A; Prawer, Steven; Barth, Michael; Benson, Oliver; Wolf, Thomas; Siyushev, Petr; Jelezko, Fedor; Wrachtrup, Jorg

    2010-01-01

    The realization of photonic crystals (PC) in diamond is of major importance for the entire field of spintronics based on fluorescent centers in diamond. The processing steps for the case of diamond differ from those commonly used, due to the extreme chemical and mechanical properties of this material. The present work summarizes the state of the art in the realization of PC's in diamond. It is based on the creation of a free standing diamond membrane into which the desired nano-sized patterns are milled by the use of Focused-Ion-Beam (FIB). The optimal fabrication-oriented structure parameters are predicted by simulations. The milling strategies, the method of formation the diamond membrane, recipes for dielectric material-manipulation in FIB and optical characterization constraints are discussed in conjunction with their implication on PC cavity design. The thus produced structures are characterized via confocal photoluminescence.

  11. All-optical information processing in photonic crystals

    Science.gov (United States)

    Yanik, Mehmet Fatih

    This thesis covers coherent and incoherent all-optical information processing using photonic bandgap nanostructures and microcavities. The first 3 chapters introduce all-optical bistable switching, transistor and memory elements with sub-micron scale dimensions. A strategy for large scale integration without optical isolators is also described. In chapters 4 and 5, dynamically modulated photonic crystal structures are introduced. It is shown that light pulses can be stopped and stored all-optically without requiring any coherent or resonant light-matter interaction. In chapter 6, it is shown that light pulses can be coherently time-reversed by using only index modulations and linear optics. In chapter 7, a supercomputer implementation of an object oriented finite difference time domain simulation is described to simulate photonic nanostructures with arbitrary material & geometric features.

  12. Strongly Driven Crystallization Processes in a Metallic Glass

    Energy Technology Data Exchange (ETDEWEB)

    LaGrange, T; Grummon, D S; Reed, B W; Browning, N D; King, W E; Campbell, G H

    2009-02-09

    The crystallization of amorphous NiTi thin films was studied in situ using pulsed laser heating in a dynamic transmission electron microscope. A single pulse can crystallize small areas of the film within 2 {micro}s. The crystallized volume fraction and morphology depend strongly on the laser energy, the laser spatial profile, and the heat transport in the film. As compared to slower furnace and continuous wave laser annealing, pulsed laser heating produces a dramatically different microstructure. Higher than expected crystallization rates were observed under pulsed irradiation that do not correlate with kinetic data obtained from the slow-heating crystallization experiments.

  13. Cooling treatment of olive paste during the oil processing: Impact on the yield and extra virgin olive oil quality.

    Science.gov (United States)

    Veneziani, G; Esposto, S; Taticchi, A; Urbani, S; Selvaggini, R; Di Maio, I; Sordini, B; Servili, M

    2017-04-15

    In recent years, the temperature of processed olives in many olive-growing areas was often close to 30°C, due to the global warming and an early harvesting period. Consequently, the new trends in the extraction process have to include the opportunity to cool the olives or olive paste before processing to obtain high quality EVOO. A tubular thermal exchanger was used for a rapid cooling treatment (CT) of olive paste after crushing. The results did not show a significant difference in the oil yield or any modifications in the legal parameters. The cooling process determined a significant improvement of phenolic compounds in all the three Italian cultivar EVOOs analyzed, whereas the volatile compounds showed a variability largely affected by the genetic origin of the olives with C6 aldehydes that seem to be more stable than C6 alcohols and esters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Study on cooling process of cryogenic system for superconducting magnets of BEPCⅡ

    Institute of Scientific and Technical Information of China (English)

    ZONG Zhan-Guo; LIU Li-Qiang; XIONG Lian-You; LI Shao-Peng; XU Qing-Jin; HE Kun; ZHANG Liang; GAO Jie

    2008-01-01

    In the upgrade project of the Beijing Electron Positron Collider(BEPCⅡ),three superconducting magnets are employed to realize the goal of two orders of magnitude higher luminosity.A cryogenic system with a total capacity of 0.5 kW at 4.5 K was built at the Institute of High Energy Physics(IHEP)to support the operations of these superconducting devices.For preparing the commissioning of the system,the refrigeration process Was simulated and analyrzed numerically.The numerical model Was based on the latest engineering progress and focused on the normal operation mode.The pressure and temperature profiles of the cryogenic system are achieved with the simulation.The influence of the helium mass flow rates to cool superconducting magnets on the thermodynamic parameters of their normal operation is also studied and discussed in this paper.

  15. Effect of Fe2O3 on the crystallization behavior of glass-ceramics produced from naturally cooled yellow phosphorus furnace slag

    Science.gov (United States)

    Liu, Hong-pan; Huang, Xiao-feng; Ma, Li-ping; Chen, Dan-li; Shang, Zhi-biao; Jiang, Ming

    2017-03-01

    CaO-Al2O3-SiO2 (CAS) glass-ceramics were prepared via a melting method using naturally cooled yellow phosphorus furnace slag as the main raw material. The effects of the addition of Fe2O3 on the crystallization behavior and properties of the prepared glass-ceramics were studied by differential thermal analysis, X-ray diffraction, and scanning electron microscopy. The crystallization activation energy was calculated using the modified Johnson-Mehl-Avrami equation. The results show that the intrinsic nucleating agent in the yellow phosphorus furnace slag could effectively promote the crystallization of CAS. The crystallization activation energy first increased and then decreased with increasing amount of added Fe2O3. At 4wt% of added Fe2O3, the crystallization activation energy reached a maximum of 676.374 kJ·mol-1. The type of the main crystalline phase did not change with the amount of added Fe2O3. The primary and secondary crystalline phases were identified as wollastonite (CaSiO3) and hedenbergite (CaFe(Si2O6)), respectively.

  16. TRISO-Coated Fuel Processing to Support High Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Del Cul, G.D.

    2002-10-01

    The initial objective of the work described herein was to identify potential methods and technologies needed to disassemble and dissolve graphite-encapsulated, ceramic-coated gas-cooled-reactor spent fuels so that the oxide fuel components can be separated by means of chemical processing. The purpose of this processing is to recover (1) unburned fuel for recycle, (2) long-lived actinides and fission products for transmutation, and (3) other fission products for disposal in acceptable waste forms. Follow-on objectives were to identify and select the most promising candidate flow sheets for experimental evaluation and demonstration and to address the needs to reduce technical risks of the selected technologies. High-temperature gas-cooled reactors (HTGRs) may be deployed in the next -20 years to (1) enable the use of highly efficient gas turbines for producing electricity and (2) provide high-temperature process heat for use in chemical processes, such as the production of hydrogen for use as clean-burning transportation fuel. Also, HTGR fuels are capable of significantly higher burn-up than light-water-reactor (LWR) fuels or fast-reactor (FR) fuels; thus, the HTGR fuels can be used efficiently for transmutation of fissile materials and long-lived actinides and fission products, thereby reducing the inventory of such hazardous and proliferation-prone materials. The ''deep-burn'' concept, described in this report, is an example of this capability. Processing of spent graphite-encapsulated, ceramic-coated fuels presents challenges different from those of processing spent LWR fuels. LWR fuels are processed commercially in Europe and Japan; however, similar infrastructure is not available for processing of the HTGR fuels. Laboratory studies on the processing of HTGR fuels were performed in the United States in the 1960s and 1970s, but no engineering-scale processes were demonstrated. Currently, new regulations concerning emissions will impact the

  17. THERMODYNAMICS AND NANOSTRUCTURAL MECHANISMS OF PROCESSES OF MELTING AND CRYSTALLIZATION OF METALS

    Directory of Open Access Journals (Sweden)

    V. Yu. Stetsenko

    2016-01-01

    Full Text Available Melting and crystallization of metals are equilibrium thermodynamic processes. As the main structural units of dendrites serve construction nanocrystals which are formed of elementary nanocrystals. The main mechanisms of processes of melting and crystallization of metals are disintegration of dendrites on nanocrystals and formation of dendrites from nanocrystals. On process of crystallization and morphology of dendrites the great influence is exerted by the hardening speed, surface-active elements and the dissolved gases.

  18. Modeling of Rocket Fuel Heating and Cooling Processes in the Interior Receptacle Space of Ground-Based Systems

    Directory of Open Access Journals (Sweden)

    K. I. Denisova

    2016-01-01

    Full Text Available The propellant to fill the fuel tanks of the spacecraft, upper stages, and space rockets on technical and ground-based launch sites before fueling should be prepared to ensure many of its parameters, including temperature, in appropriate condition. Preparation of fuel temperature is arranged through heating and cooling the rocket propellants (RP in the tanks of fueling equipment. Processes of RP temperature preparation are the most energy-intensive and timeconsuming ones, which require that a choice of sustainable technologies and modes of cooling (heating RP provided by the ground-based equipment has been made through modeling of the RP [1] temperature preparation processes at the stage of design and operation of the groundbased fueling equipment.The RP temperature preparation in the tanks of the ground-based systems can be provided through the heat-exchangers built-in the internal space and being external with respect to the tank in which antifreeze, air or liquid nitrogen may be used as the heat transfer media. The papers [1-12], which note a promising use of the liquid nitrogen to cool PR, present schematic diagrams and modeling systems for the RP temperature preparation in the fueling equipment of the ground-based systems.We consider the RP temperature preparation using heat exchangers to be placed directly in RP tanks. Feeding the liquid nitrogen into heat exchanger with the antifreeze provides the cooling mode of PR while a heated air fed there does that of heating. The paper gives the systems of equations and results of modeling the processes of RP temperature preparation, and its estimated efficiency.The systems of equations of cooling and heating RP are derived on the assumption that the heat exchange between the fuel and the antifreeze, as well as between the storage tank and the environment is quasi-stationary.The paper presents calculation results of the fuel temperature in the tank, and coolant temperature in the heat exchanger, as

  19. Evaluation of a method for heat transfer measurements and thermal visualization using a composite of a heater element and liquid crystals. [thermal performance of turbine blade cooling configurations

    Science.gov (United States)

    Hippensteele, S. A.; Russell, L. M.; Stepka, F. S.

    1981-01-01

    Commercially available elements of a composite consisting of a plastic sheet coated with liquid crystal, another sheet with a thin layer of a conducting material (gold or carbon), and copper bus bar strips were evaluated and found to provide a simple, convenient, accurate, and low-cost measuring device for use in heat transfer research. The particular feature of the composite is its ability to obtain local heat transfer coefficients and isotherm patterns that provide visual evaluation of the thermal performances of turbine blade cooling configurations. Examples of the use of the composite are presented.

  20. Crystallization: A phase transition process driving by chemical potential decrease

    Science.gov (United States)

    Sun, Congting; Xue, Dongfeng

    2017-07-01

    A chemical bonding model is established to describe the chemical potential decrease during crystallization. In the nucleation stage, in situ molecular vibration spectroscopy shows the increased vibration energy of constituent groups, indicating the shortened chemical bonding and the decreased chemical potential towards the formation of nuclei. Starting from the Gibbs free energy formula, the chemical potential decrease during crystallization is scaled, which depends on the released chemical bonding energy per unit phase transition zone. In the crystal growth, the direction-dependent growth rate of inorganic single crystals can be quantitatively determined, their anisotropic thermodynamic morphology can thus be constructed on the basis of relative growth rates.

  1. Application of evolutionary algorithms to optimize the model parameters of casting cooling process

    Directory of Open Access Journals (Sweden)

    S. Kluska-Nawarecka

    2010-10-01

    Full Text Available One of the most commonly used methods of numerical simulation is the finite element method (FEM. Its popularity is reflected in thenumber of tools supporting the preparation of simulation models. However, despite its usefulness, FEM is often very troublesome in use;the problem is the selection of the finite element mesh or shape function. In addition, MES assumes a complete knowledge of thesimulated process and of the parameters describing the investigated phenomena, including model geometry, boundary conditions, physicalparameters, and mathematical model describing these phenomena. A comparison of the data obtained from physical experiments andsimulations indicates an inaccuracy, which may result from the incorrectly chosen shape of element or geometry of the grid. Theapplication of computational intelligence methods, combined with knowledge of the manufacturing technology of metal products, shouldallow an efficient selection of parameters of the mathematical models and, as a consequence, more precise control of the process of thecasting solidification and cooling to ensure the required quality. The designed system has been integrated with the existing simulationenvironment, which will significantly facilitate the preparation and implementation of calculations of this type. Moreover, the use of adistributed model will significantly reduce the time complexity of calculations, requiring multiple repetition of complex simulations toestimate the quality of the different sets of parameters.

  2. Process water - waste water - cooling water. Papers; Prozesswasser/Abwasser/Kuehlwasser. Vortraege

    Energy Technology Data Exchange (ETDEWEB)

    Liese, F. (comp.)

    2002-07-01

    The 39th Metallurgical Seminar focused on water. Modern technologies for water purification and treatment were presented, legal boundary conditions were discussed, and aspects of process water, waste water and cooling water were gone into. Although the boundaries between these three types of water cannot be clearly defined, materials recovery is the prevalent aspect in process water treatment while waste water treatment primarily aims at reducing pollutant concentrations so that both environmental aspects and technical quality standards will be met. This proceedings volume attempts to give its readers a more precise picture of the issues at hand by presenting fundamental research, ecological and legal specifications, and selected examples of industrial applications. [German] Das 39. Metallurgische Seminar beschaeftigt sich mit Wasser. Neben der Praesentation grundsaetzlicher, moderner Techniken zur Reinhaltung und Aufbereitung von Wasser sowie der Darstellung der gesetzlichen Rahmenbedingungen umspannen die Fachvortraege Beitraege zu den Themen Prozesswasser, Abwasser, Kuehlwasser. Wenn auch die Grenzen innerhalb dieser Begriffe teilweise fliessend sind, so zeichnen sich die Prozesswaesser dadurch aus, dass man primaer - wie beispielsweise bei Waschsloesungen und Beizwaessern - an der Wiedergewinnung der Inhaltsstoffe interessiert ist, waehrend bei reinen Abwaessern und Kuehlturmwaessern bzw. deren Abschlaemmungen die massgebliche Aufgabe darin besteht, die Konzentration der Inhaltsstoffe so weit abzusenken, dass man einerseits den Umwelterfordernissen und andererseits den technischen Qualitaetsanforderungen gerecht wird. Ziel dieses Bandes ist es, an Hand von Grundlagen, der Darstellung der oekologischen und behoerdlichen Erfordernisse sowie ausgewaehlter Fallbeispiele aus der Industrie den Leserkreis naeher an diese Thematik heranzufuehren. (orig.)

  3. Control of Process Operations and Monitoring of Product Qualities through Generic Model-based Framework in Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin

    A generic and systematic model-based framework for the design of a process monitoring and control system to achieve the desired crystal size distribution (CSD) and crystal shape for a wide range of crystallization processes has been developed. This framework combines a generic multi......-dimensional to a twodimensional description; b) the systematic framework is used in a case study to design a monitoring and control (PAT) system for a potassium dichromate and KDP crystallization processes to achieve the desired target CSD respectively; and c) Based on the PAT system design in b), the application of uncertainty......-dimensional modelling framework, tools for design of set point profiles, for design of PAT (Process Analytical Technology) systems as well as option to perform the uncertainty and sensitivity analysis of the PAT system design. Through this framework, it is possible for a wide range of crystallization processes...

  4. Factors affecting ice crystal purity during freeze concentration process for urine treatment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Freeze concentration has great potential in treating wastewaters containing soluble pollutions. It is important for freeze concentration process to produce ice crystals with large size and high purity. In this work raw urines of 4660-7914 mg/L in COD,512.71-872.41 mg/L in NH3-N and 22600-28800μs/cm in e lectric conductivity were studied. Urines were frozen by a digital refrigerated circulator bath. Ice crystals were purified by ice-water steep and vacuum filtration. The COD,NH3-N,and electric conductivity levels of the melted ices were measured to reflect ice crystal purity. Effects of coolant temperature, ice crystal shape, initial solution temperature, solution concentration, ice seeding, re-crystallization process and crystallization time on ice crystal purity were analyzed. The results show that an appropriate coolant temperature, suspended ice crystals,an initial solution temperature of about 6 C, introduction of seed ice, addition of re-crystallization process. And crystallization time of less than 30 min are in favor of producing ice crystals with hith purity.Under such conditions, more than 99 percent of inorganic salts, COD and NH3-N sources in raw urine could be removed.

  5. Phytochemical profiles and health-promoting effects of cool-season food legumes as influenced by thermal processing.

    Science.gov (United States)

    Xu, Baojun; Chang, Sam K C

    2009-11-25

    The effects of four thermal processing methods (conventional boiling, conventional steaming, pressure boiling, and pressure steaming) on phytochemical profiles, antioxidant capacities, and antiproliferation properties of commonly consumed cool-season food legumes, including green pea, yellow pea, chickpea, and lentil, were investigated. Four groups of individual phenolic compounds, including phenolic acids, anthocyanins, and flavan-3-ols, as well as flavonols and flavones were quantified using HPLC, respectively. As compared to the original raw legumes, all processing methods caused significant (pphytic acid content, chemical antioxidant capacities in terms of ferric reducing antioxidant power and peroxyl radical scavenging capacity, and cellular antioxidant activity as well as antiproliferation capacities of cool-season food legumes. Different cooking methods have varied effects on reducing total phenolics, saponins, phytic acids, and individual phenolic compounds. For all cool-season food legumes, steaming appeared to be a better cooking method than boiling in retaining antioxidants and phenolic components, whereas boiling appeared to be effective in reducing saponin and phytic acid contents. In the case of lentil, all thermal processing methods (except conventional steaming) caused significant (pacid, and total phenolic acid. All thermal processing methods caused significant (p<0.05) decreases in (+)-catechin and flavan-3-ols in each cool-season food legume.

  6. Impact of cooling condition on the crystal structure and surface quality of preferred c-axis-oriented AIN films for SAW devices

    Institute of Scientific and Technical Information of China (English)

    ZHANG Geng-yu; YANG Bao-he; ZHAO Jian; LI Cui-ping; LI Ming-ji

    2011-01-01

    AIN films with preferred c-axis orientation are deposited on Si substrates using the radio frequency (RF) magnetron sputtering method. The post-processing is carried out under the cooling conditions including high vacuum, low vacuum under deposition gas ambient and low vacuum under dynamic N2 ambient. Structures and morphologies of the films are analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The hardness and Young's modulus are investigated by the nanoindenter. The experimental results indicate that the (100) and (110) peak intensities decrease in the XRD spectra and the root-mean-square of roughness (Rrms) of the film decreases gradually with the increase of the cooling rate. The maximum values of the hardness and Young's modulus are obtained by cooling in low vacuum under deposition gas ambient. The reason for orientation variation of the films is explained from the perspective of the Al-N bond formation.

  7. Numerical investigations of transient heat transfer characteristics and vitrification tendencies in ultra-fast cell cooling processes.

    Science.gov (United States)

    Jiao, Anjun; Han, Xu; Critser, John K; Ma, Hongbin

    2006-06-01

    During freezing, cells are often damaged directly or indirectly by ice formation. Vitrification is an alternative approach to cryopreservation that avoids ice formation. The common method to achieve vitrification is to use relatively high concentrations of cryoprotectant agents (CPA) in combination with a relatively slow cooling rate. However, high concentrations of CPAs have potentially damaging toxic and/or osmotic effects on cells. Therefore, establishing methods to achieve vitrification with lower concentrations of CPAs through ultra-fast cooling rates would be advantageous in these aspects. These ultra-fast cooling rates can be realized by a cooling system with an ultra-high heat transfer coefficient (h) between the sample and coolant. The oscillating motion heat pipe (OHP), a novel cooling device utilizing the pressure change to excite the oscillation motion of the liquid plugs and vapor bubbles, can significantly increase h and may fulfill this aim. The current investigation was designed to numerically study the effects of different values of h on the transient heat transfer characteristics and vitrification tendencies of the cell suspension during the cooling processes in an ultra-thin straw (100 microm in diameter). The transient temperature distribution, the cooling rate and the volume ratio (x) of the ice quantity to the maximum crystallizable ice of the suspension were calculated. From these numerical results, it is concluded that the ultra-high h (>10(4) W/m2 K) obtained by OHPs could facilitate vitrification by efficiently decreasing x as well as the time to pass through the dangerous temperature region where the maximum ice formation happens. For comparison, OHPs can decrease both of the parameters to less than 20% of those from the widely used open pulled straw methods. Therefore, the OHP method will be a promising approach to improving vitrification tendencies of CPA solutions and could also decrease the required concentration of CPAs for

  8. Manufacturing Process Developments for Regeneratively-Cooled Channel Wall Rocket Nozzles

    Science.gov (United States)

    Gradl, Paul; Brandsmeier, Will

    2016-01-01

    Regeneratively cooled channel wall nozzles incorporate a series of integral coolant channels to contain the coolant to maintain adequate wall temperatures and expand hot gas providing engine thrust and specific impulse. NASA has been evaluating manufacturing techniques targeting large scale channel wall nozzles to support affordability of current and future liquid rocket engine nozzles and thrust chamber assemblies. The development of these large scale manufacturing techniques focus on the liner formation, channel slotting with advanced abrasive water-jet milling techniques and closeout of the coolant channels to replace or augment other cost reduction techniques being evaluated for nozzles. NASA is developing a series of channel closeout techniques including large scale additive manufacturing laser deposition and explosively bonded closeouts. A series of subscale nozzles were completed evaluating these processes. Fabrication of mechanical test and metallography samples, in addition to subscale hardware has focused on Inconel 625, 300 series stainless, aluminum alloys as well as other candidate materials. Evaluations of these techniques are demonstrating potential for significant cost reductions for large scale nozzles and chambers. Hot fire testing is planned using these techniques in the future.

  9. Real-time processing of interferograms for monitoring protein crystal growth on the Space Station

    Science.gov (United States)

    Choudry, A.; Dupuis, N.

    1988-01-01

    The possibility of using microscopic interferometric techniques to monitor the growth of protein crystals on the Space Station is studied. Digital image processing techniques are used to develop a system for the real-time analysis of microscopic interferograms of nucleation sites during protein crystal growth. Features of the optical setup and the image processing system are discussed and experimental results are presented.

  10. Real-time processing of interferograms for monitoring protein crystal growth on the Space Station

    Science.gov (United States)

    Choudry, A.; Dupuis, N.

    1988-01-01

    The possibility of using microscopic interferometric techniques to monitor the growth of protein crystals on the Space Station is studied. Digital image processing techniques are used to develop a system for the real-time analysis of microscopic interferograms of nucleation sites during protein crystal growth. Features of the optical setup and the image processing system are discussed and experimental results are presented.

  11. Materials Reliability Program: Development of a New Process for Calculating RPV Heat-Up and Cool-Down Curves - Proof of Concept

    Energy Technology Data Exchange (ETDEWEB)

    M. EricksonKirk

    2005-04-30

    A strategy and framework were developed for incorporating best-estimate, fracture toughness models and methodologies into procedures for fracture safety assessment of nuclear RPVs during normal heat-up and cool-down operations. The process included detailed process flow diagramming to identify all details of the current process for obtaining heat-up and cool-down curves.

  12. Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

    CERN Document Server

    Sokolov, Sergei; Yüce, Emre; Combrié, Sylvain; Lehoucq, Gaelle; De Rossi, Alfredo; Mosk, Allard P

    2015-01-01

    We perform a spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: helium and nitrogen. The use of high-conducting gas in combination with low-conducting semiconductor leads to a resonance control with a spatial resolution better than 4 microns.

  13. Fast and scalable purification of a therapeutic full-length antibody based on process crystallization.

    Science.gov (United States)

    Smejkal, Benjamin; Agrawal, Neeraj J; Helk, Bernhard; Schulz, Henk; Giffard, Marion; Mechelke, Matthias; Ortner, Franziska; Heckmeier, Philipp; Trout, Bernhardt L; Hekmat, Dariusch

    2013-09-01

    The potential of process crystallization for purification of a therapeutic monoclonal IgG1 antibody was studied. The purified antibody was crystallized in non-agitated micro-batch experiments for the first time. A direct crystallization from clarified CHO cell culture harvest was inhibited by high salt concentrations. The salt concentration of the harvest was reduced by a simple pretreatment step. The crystallization process from pretreated harvest was successfully transferred to stirred tanks and scaled-up from the mL-scale to the 1 L-scale for the first time. The crystallization yield after 24 h was 88-90%. A high purity of 98.5% was reached after a single recrystallization step. A 17-fold host cell protein reduction was achieved and DNA content was reduced below the detection limit. High biological activity of the therapeutic antibody was maintained during the crystallization, dissolving, and recrystallization steps. Crystallization was also performed with impure solutions from intermediate steps of a standard monoclonal antibody purification process. It was shown that process crystallization has a strong potential to replace Protein A chromatography. Fast dissolution of the crystals was possible. Furthermore, it was shown that crystallization can be used as a concentrating step and can replace several ultra-/diafiltration steps. Molecular modeling suggested that a negative electrostatic region with interspersed exposed hydrophobic residues on the Fv domain of this antibody is responsible for the high crystallization propensity. As a result, process crystallization, following the identification of highly crystallizable antibodies using molecular modeling tools, can be recognized as an efficient, scalable, fast, and inexpensive alternative to key steps of a standard purification process for therapeutic antibodies.

  14. A generic multi-dimensional model-based system for batch cooling crystallization processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    2011-01-01

    Highly porous deposits of flame-made aerosol nanoparticles were formed by filtration through a porous substrate (α-alumina, average pore diameter 3.7 μm). The aerosol was characterized by transmission electron microscopy (TEM) and scanning mobility particle sizer (SMPS) showing average primary an...

  15. Economia de escala no processo de resfriamento do leite Economies of scale in the milk cooling process

    Directory of Open Access Journals (Sweden)

    Marcela de Mello Brandão Vinholis

    2009-02-01

    Full Text Available Objetivou-se, neste artigo, estimar os custos envolvidos no processo de resfriamento do leite cru, tipo B, após a implantação da Instrução Normativa 51 e a verificação das possíveis fontes de economias de escala nesse processo. A partir dos conceitos da engenharia econômica calculou-se o custo uniforme líquido equivalente de investimento do processo de resfriamento do leite, que somado ao custo operacional, resultou no custo uniforme líquido total por litro de leite. Concluiu-se que existe forte tendência à economia de escala nessa atividade devido aos retornos crescentes no custo de investimento e operacional, conforme aumenta-se a capacidade dos tanques de resfriamento.This article aims to estimate the costs involved in the milk cooling process after the Normative Instruction 51 was issued and it also aims to verify the sources of economies scale. Using the concepts of the economical engineering, the uniform net costs of the investment in the milk cooling process were calculated. They were added to the operational cost and it resulted in the total uniform net cost per unit. It was concluded that there is a strong tendency to economies scale in the milk cooling process as a consequence of the growing returns in the investment and operational costs as the milk cooling tank capacity increases.

  16. A Generic Framework for Systematic Design of Process Monitoring and Control System for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Meisler, Kresten Troelstrup; Sin, Gürkan

    , for control and monitoring purposes, an appropriate Process Analytical Technology (PAT) system ensuring that the critical process variables are measured and maintained within the design limits also needs to be integrated. The objectives of this work are to develop a generic systematic design framework...... for monitoring and control systems applicable to a wide range of crystallization processes and operational scenarios. This framework contains a generic multi-dimensional modelling framework and features for design of operational scenarios and for design of PAT systems. The generality of this approach allows...... the desired target CSD. The generated operational policies provide the supersaturation set point and by maintaining the operation at this point, the targeted CSD is achieved. The resulting problem-system specific models and the operational policies become ready for use in model-based design and control...

  17. More accurate determination of the quantity of ice crystallized at low cooling rates in the glycerol and 1,2-propanediol aqueous solutions: comparison with equilibrium.

    Science.gov (United States)

    Boutron, P

    1984-04-01

    It is generally assumed that when cells are cooled at rates close to those corresponding to the maximum of survival, once supercooling has ceased, above the eutectic melting temperature the extracellular ice is in equilibrium with the residual solution. This did not seem evident to us due to the difficulty of ice crystallization in cryoprotective solutions. The maximum quantities of ice crystallized in glycerol and 1,2-propanediol solutions have been calculated from the area of the solidification and fusion peaks obtained with a Perkin-Elmer DSC-2 differential scanning calorimeter. The accuracy has been improved by several corrections: better defined baseline, thermal variation of the heat of fusion of the ice, heat of solution of the water from its melting with the residual solution. More ice crystallizes in the glycerol than in the 1,2-propanediol solutions, of which the amorphous residue contains about 40 to 55% 1,2-propanediol. The equilibrium values are unknown in the presence of 1,2-propanediol. With glycerol, in our experiments, the maximum is first lower than the equilibrium but approaches it as the concentration increases. It is not completely determined by the colligative properties of the solutes.

  18. Experimental investigation of photon multiplicity and radiation cooling for 150 GeV electrons/positrons traversing diamond and Si crystals

    Science.gov (United States)

    Kirsebom, K.; Medenwaldt, R.; Mikkelsen, U.; Møller, S. P.; Paludan, K.; Uggerhøj, E.; Worm, T.; Elsener, K.; Ballestrero, S.; Sona, P.; Romano, J.; Connell, S. H.; Sellschop, J. P. F.; Avakian, R. O.; Avetisian, A. E.; Taroian, S. P.

    1996-10-01

    Detailed experimental investigations of photon multiplicities for 150 GeV electrons/positrons traversing thin diamond and Si crystals have been performed. Along axial directions up to 10 photons are emitted in 1.5 mm diamond for a radiative energy loss larger than 4 GeV. This corresponds to a mean free path for photon emission of about two orders of magnitude shorter than in an amorphous target. This is in agreement with an enhanced radiative energy loss of ˜ 30 times that in amorphous targets. The strongly enhanced photon emission leads to radiation cooling which can result in particles exiting the crystal with a reduced angle to the axis. For incidences along planar directions the average multiplicity is still above one, even for the thinnest crystals used in the present experiment, so a single-photon spectrum can only be obtained for thicknesses ≤50 μm, which, on the other hand, is comparable to the coherence lengths for GeV photons, leading to destruction of the coherent effects.

  19. Unusual crystals of poly(ε-caprolactone) by unusual crystallisation: The effects of rapid cooling and fast solvent loss on the morphology, crystal structure and melting

    NARCIS (Netherlands)

    Sanandaji, N.; Ovaskainen, L.; Klein Gunnewiek, M.; Vancso, G.J.; Hedenqvist, M.S.; Yu, S.; Eriksson, L.; Roth, S.V.; Gedde, U.W.

    2013-01-01

    The lateral habit, unit cell structure and melting behaviour of single crystals of poly(ε-caprolactone) (PCL) prepared by the rapid expansion of a supercritical solution technique was studied by AFM at ambient and higher temperatures and by grazing-incident X-ray scattering using a synchrotron sourc

  20. Patterning technology for solution-processed organic crystal field-effect transistors

    OpenAIRE

    Yun Li; Huabin Sun; Yi Shi; Kazuhito Tsukagoshi

    2014-01-01

    Organic field-effect transistors (OFETs) are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development...

  1. Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Sergei, E-mail: s.sokolov@utwente.nl; Lian, Jin; Yüce, Emre; Mosk, Allard P. [Complex Photonic Systems (COPS), MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Combrié, Sylvain; Lehoucq, Gaelle; De Rossi, Alfredo [Thales Research and Technology, Route Départementale 128, 91767 Palaiseau (France)

    2015-04-27

    We perform spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: He and N{sub 2}. We find that the width of the temperature profile induced in the membrane depends strongly on the thermal conductivity of the ambient gas. For He gas, a narrow spatial width of the temperature profile of 2.8 μm is predicted and verified in experiment.

  2. Simulation of cooling channel rheocasting process of A356 aluminum alloy using three-phase volume averaging model

    Institute of Scientific and Technical Information of China (English)

    T. Wang; B.Pustal; M. Abondano; T. Grimmig; A. B(u)hrig-Polaczek; M. Wu; A. Ludwig

    2005-01-01

    The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process. A three-phase model based on volume averaging approach is proposed to simulate the cooling channel process of A356 Aluminum alloy. The three phases are liquid, solid and air respectively and treated as separated and interacting continua, sharing a single pressure field. The mass, momentum, enthalpy transport equations for each phase are solved. The developed model can predict the evolution of liquid, solid and air fraction as well as the distribution of grain density and grain size. The effect of pouring temperature on the grain density, grain size and solid fraction is analyzed in detail.

  3. Characterization of the Bridgman crystal growth process by radiographic imaging

    Science.gov (United States)

    Fripp, Archibald L.; Debnam, W. J.; Woodell, G. W.; Berry, R. F.; Simchick, R. T.; Sorokach, S. K.; Barber, P. G.

    1991-01-01

    Elemental (Ge) and alloy (PbSnTe) crystal growth that is monitored via radiography to reveal both the interface position and the shape in real time is discussed for both seeded and unseeded growth. It is concluded that the interface position and the actual growth rate of a Bridgman grown crystal is dependent on the growth conditions. The actual growth rate which is a strong function of the degree of supercooling exceeded the pull rate by a factor of greater than two. The interface shape changed from concave to flat to convex during the growth.

  4. Characterization of the Bridgman crystal growth process by radiographic imaging

    Science.gov (United States)

    Fripp, Archibald L.; Debnam, W. J.; Woodell, G. W.; Berry, R. F.; Simchick, R. T.; Sorokach, S. K.; Barber, P. G.

    1991-01-01

    Elemental (Ge) and alloy (PbSnTe) crystal growth that is monitored via radiography to reveal both the interface position and the shape in real time is discussed for both seeded and unseeded growth. It is concluded that the interface position and the actual growth rate of a Bridgman grown crystal is dependent on the growth conditions. The actual growth rate which is a strong function of the degree of supercooling exceeded the pull rate by a factor of greater than two. The interface shape changed from concave to flat to convex during the growth.

  5. Rapid crystallization of externally produced ions in a Penning trap

    CERN Document Server

    Murboeck, T; Birkl, G; Noertershaeuser, W; Thompson, R C; Vogel, M

    2016-01-01

    We have studied the cooling dynamics, formation process and geometric structure of mesoscopic crystals of externally produced magnesium ions in a Penning trap. We present a cooling model and measurements for a combination of buffer gas cooling and laser cooling which has been found to reduce the ion kinetic energy by eight orders of magnitude from several hundreds of eV to micro-eV and below within seconds. With ion numbers of the order of 1000 to 100000, such cooling leads to the formation of ion Coulomb crystals which display a characteristic shell structure in agreement with theory of non-neutral plasmas. We show the production and characterization of two-species ion crystals as a means of sympathetic cooling of ions lacking a suitable laser-cooling transition.

  6. Optimizing the crystal size and habit of beta-sitosterol in suspension

    DEFF Research Database (Denmark)

    von Bonsdorff-Nikander, Anna; Rantanen, Jukka; Christiansen, Leena

    2003-01-01

    The aim of this work was to survey how processing parameters affect the crystal growth of beta-sitosterol in suspension. The process variables studied were the cooling temperature, stirring time and stirring rate during recrystallization. In addition, we investigated the effect a commonly used...... surfactant, polysorbate 80, has on crystal size distribution and the polymorphic form. This study describes the optimization of the crystallization process, with the object of preparing crystals as small as possible. Particle size distribution and habit were analyzed using optical microscopy, and the crystal...... structure was analyzed using X-ray diffractometry. The cooling temperature had a remarkable influence on the crystal size. Crystals with a median crystal length of approximately 23 microm were achieved with a low cooling temperature (crystals over 50 microm...

  7. Effect of cooling and rewarming rate on crystallization of cryoprotectant solution for oocytes%升降温速率对低温保护剂溶液结晶性质的影响

    Institute of Scientific and Technical Information of China (English)

    李维杰; 周新丽; 刘宝林; 吕福扣

    2013-01-01

    When cells are cryopreserved,the morphology of cryoprotectant at crystallization and recrystallization would influence the survival rate of cells.The cryo-microscope system was used to observe the morphology of crystal and sizes of two cryoprotectants during cooling and rewarming at different speeds.It is found that crystals during cooling are smaller and less at higher speed than at lower speed,and the former is favorable for preservation of cells.When the vitrified cryoprotetant is rewarmed,crystals during recrystallization are smaller and less at higher speed than at lower speed,and the former with narrow danger zone is favorable for the survival of oocytes.Besides,high concentration of cryoprotectant is more favorable for the survivalrate of oocytes than lower concentration.

  8. Hard Fats As Additives In Palm Oil And Its Relationships To Crystallization Process And Polymorphism

    OpenAIRE

    Oliveira, MR; Glazieli Marangoni; Ribeiro; Ana Paula Badan; dos Santos; Adenilson Oliveira; Cardoso; Lisandro Pavie; Kieckbusch; Theo Guenter

    2016-01-01

    The application of palm oil in fat-based product can be inappropriate due to its low crystallization rates and formation of crystalline clusters in post-processing stages. The adjustment of these properties can be achieved with the addition of hard fats, which are low-cost industrial products resulting from the process of total catalytic hydrogenation of liquid oils. During the crystallization of palm oil, these components can act as preferential nuclei in a crystalline ordering process, and ...

  9. Process Intensification in Crystallization: Submicron Particle Generation Using Alternative Energy Forms

    NARCIS (Netherlands)

    Radacsi, N.

    2012-01-01

    Crystallization is one of the oldest separation and product formation techniques that continues to be in use today. Despite its long history, it only started to develop significantly in the past few decades. In this thesis, the application of Process Intensification in crystallization is

  10. Process Intensification in Crystallization: Submicron Particle Generation Using Alternative Energy Forms

    NARCIS (Netherlands)

    Radacsi, N.

    2012-01-01

    Crystallization is one of the oldest separation and product formation techniques that continues to be in use today. Despite its long history, it only started to develop significantly in the past few decades. In this thesis, the application of Process Intensification in crystallization is investigate

  11. Effects of cooling rate and stabilization annealing on fatigue behavior of β-processed Ti-6Al-4V alloys

    Science.gov (United States)

    Seo, Wongyu; Jeong, Daeho; Lee, Dongjun; Sung, Hyokyung; Kwon, Yongnam; Kim, Sangshik

    2017-07-01

    The effects of stabilization annealing and cooling rate on high cycle fatigue (HCF) and fatigue crack propagation (FCP) behaviors of β-processed Ti64 alloys were examined. After β-process heating above β transus, two different cooling rates of air cooling (β-annealing) and water quenching (β-quenching) were utilized. Selected specimens were then underwent stabilization annealing. The tensile tests, HCF and FCP tests on conducted on the β-processed Ti64 specimens with and without stabilization annealing. No notable microstructural and mechanical changes with stabilization annealing was observed for the β-annealed Ti64 alloys. However, significant effect of stabilization annealing was found on the FCP behavior of β-quenched Ti64 alloys, which appeared to be related to the built-up of residual stress after quenching. The mechanical behavior of β-processed Ti64 alloys with and with stabilization annealing was discussed based on the micrographic examination, including crack growth path and crack nucleation site, and fractographic analysis.

  12. Use of process steam in vapor absorption refrigeration system for cooling and heating applications: An exergy analysis

    Directory of Open Access Journals (Sweden)

    S. Anand

    2016-12-01

    Full Text Available The exponential increase in cost of conventional fuels shifts the interest toward the use of alternative as well waste energy sources for the operation of refrigeration and air-conditioning units. The present study therefore analyzes the performance of a process steam-operated vapor absorption system for cooling and heating applications using ammonia and water as working fluids based on first and second laws of thermodynamics. A mathematical model has been developed based on exergy analysis to investigate the performance of the system. The different performance parameters such as coefficient of performance (COP and exergetic efficiency of absorption system for cooling and heating applications are also calculated under different operating conditions. The results obtained show that cooling and heating COP along with second law efficiency (exergy efficiency increases with the heat source temperature at constant evaporator, condenser, and absorber temperature. Also, COP as well as exergy efficiency increases with an increase in the evaporator temperature at constant generator, condenser, and absorber temperature. The effect of ambient temperature on the exergetic efficiency for cooling and heating applications is also studied. The results obtained from the simulation studies can be used to optimize different components of the system so that the performance can be improved significantly.

  13. Photonic Crystal Nanocavity Devices for Nonlinear Signal Processing

    DEFF Research Database (Denmark)

    Yu, Yi

    , membranization of InP/InGaAs structure and wet etching. Experimental investigation of the switching dynamics of InP photonic crystal nanocavity structures are carried out using short-pulse homodyne pump-probe techniques, both in the linear and nonlinear region where the cavity is perturbed by a relatively small......This thesis deals with the investigation of InP material based photonic crystal cavity membrane structures, both experimentally and theoretically. The work emphasizes on the understanding of the physics underlying the structures’ nonlinear properties and their applications for all-optical signal...... and large pump power. The experimental results are compared with coupled mode equations developed based on the first order perturbation theory, and carrier rate equations we established for the dynamics of the carrier density governing the cavity properties. The experimental observations show a good...

  14. Crystal-Tolerant Glass Approach For Mitigation Of Crystal Accumulation In Continuous Melters Processing Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Rodriguez, Carmen P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lang, Jesse B. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Huckleberry, Adam R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Matyas, Josef [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Owen, Antoinette T. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2012-08-28

    High-level radioactive waste melters are projected to operate in an inefficient manner as they are subjected to artificial constraints, such as minimum liquidus temperature (T{sub L}) or maximum equilibrium fraction of crystallinity at a given temperature. These constraints substantially limit waste loading, but were imposed to prevent clogging of the melter with spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr){sub 2}O{sub 4}]. In the melter, the glass discharge riser is the most likely location for crystal accumulation during idling because of low glass temperatures, stagnant melts, and small diameter. To address this problem, a series of lab-scale crucible tests were performed with specially formulated glasses to simulate accumulation of spinel in the riser. Thicknesses of accumulated layers were incorporated into empirical model of spinel settling. In addition, T{sub L} of glasses was measured and impact of particle agglomeration on accumulation rate was evaluated. Empirical model predicted well the accumulation of single crystals and/or smallscale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ~14.9 +- 1 nm/s determined for this glass will result in ~26 mm thick layer in 20 days of melter idling.

  15. Application of Hot Strength and Ductility Test to Optimization of Secondary Cooling System in Billet Continuous Casting Process

    Institute of Scientific and Technical Information of China (English)

    WANG Biao; JI Zhen-ping; LIU Wen-hong; MA Jiao-cheng; XIE Zhi

    2008-01-01

    By means of Gleeble-1500 dynamic thermomechanical simulator,the continuous casting process for HRB335C steel was simulated using solidifying method and hot ductility and strength of the steel were determined.The test results indicate that there are three temperature regions of brittleness for HRB335C billet in the temperature range from 700℃ to solidification point;the first temperature region of brittleness is 1 300℃ to solidification point of the billet,the second temperature region of brittleness is 1 200-1 000℃,and the third temperature region of brittleness is 700-850℃;the steel is plastic at 850-1 000℃.The cracking sensitivity was studied in the different temperature zones of the brittleness for steel HRB335C and the target surface temperature curve for the secondary cooling is determined.With optimized process,the mathematical model of the steady temperature field with two-dimensional heat transfer for 150 mm×150 mm HRB335C steel billet was established to optimize the secondary cooling process.The conic relation of water distribution between secondary cooling water flux and casting speed is regressed.Keeping the surface temperature of billet before the straightening point above 1 000℃,the results of billet test indicate that there is free central shrinkage cavity.The billet defect is decreased greatly,and the quality of billet is obviously improved.

  16. Different supercontinuum generation processes in photonic crystal fibers pumped with a 1064-nm picosecond pulse

    Science.gov (United States)

    Chen, Hong-Wei; Jin, Ai-Jun; Chen, Sheng-Ping; Hou, Jing; Lu, Qi-Sheng

    2013-08-01

    Picosecond pulse pumped supercontinuum generation in photonic crystal fiber is investigated by performing a series of comparative experiments. The main purpose is to investigate the supercontinuum generation processes excited by a given pump source through the experimental study of some specific fibers. A 20-W all-fiber picosecond master oscillator-power amplifier (MOPA) laser is used to pump three different kinds of photonic crystal fibers for supercontinuum generation. Three diverse supercontinuum formation processes are observed to correspond to photonic crystal fibers with distinct dispersion properties. The experimental results are consistent with the relevant theoretical results. Based on the above analyses, a watt-level broadband white light supercontinuum source spanning from 500 nm to beyond 1700 nm is demonstrated by using a picosecond fiber laser in combination with the matched photonic crystal fiber. The limitation of the group velocity matching curve of the photonic crystal fiber is also discussed in the paper.

  17. Different supercontinuum generation processes in photonic crystal fibers pumped with a 1064-nm picosecond pulse

    Institute of Scientific and Technical Information of China (English)

    Chen Hong-Wei; Jin Ai-Jun; Chen Sheng-Ping; Hou Jing; Lu Qi-Sheng

    2013-01-01

    Picosecond pulse pumped supercontinuum generation in photonic crystal fiber is investigated by performing a series of comparative experiments.The main purpose is to investigate the supercontinuum generation processes excited by a given pump source through the experimental study of some specific fibers.A 20-W all-fiber picosecond master oscillator-power amplifier (MOPA) laser is used to pump three different kinds of photonic crystal fibers for supercontinuum generation.Three diverse supercontinuum formation processes are observed to correspond to photonic crystal fibers with distinct dispersion properties.The experimental results are consistent with the relevant theoretical results.Based on the above analyses,a watt-level broadband white light supercontinuum source spanning from 500 nm to beyond 1700 nm is demonstrated by using a picosecond fiber laser in combination with the matched photonic crystal fiber.The limitation of the group velocity matching curve of the photonic crystal fiber is also discussed in the paper.

  18. Concomitant crystallization for in situ encapsulation of organic materials

    NARCIS (Netherlands)

    Reus, M.A.; Hoetmer, G.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2014-01-01

    Concomitant crystallization leads to process intensification through the synergistic combination of the partial processes of particle formation and encapsulation within a single process step. Both cooling and electrospray crystallization in multi-component solutions were used to create (sub-)micron

  19. Concomitant crystallization for in situ encapsulation of organic materials

    NARCIS (Netherlands)

    Reus, M.A.; Hoetmer, G.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2014-01-01

    Concomitant crystallization leads to process intensification through the synergistic combination of the partial processes of particle formation and encapsulation within a single process step. Both cooling and electrospray crystallization in multi-component solutions were used to create (sub-)micron

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-03

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-03

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

  2. Thermal-capillary analysis of Czochralski and liquid encapsulated Czochralski crystal growth. II - Processing strategies

    Science.gov (United States)

    Derby, J. J.; Brown, R. A.

    1986-01-01

    The pseudosteady-state heat transfer model developed in a previous paper is augmented with constraints for constant crystal radius and melt/solid interface deflection. Combinations of growth rate, and crucible and bottom-heater temperatures are tested as processing parameters for satisfying the constrained thermal-capillary problem over a range of melt volumes corresponding to the sequence occuring during the batchwise Czochralski growth of a small-diameter silicon crystal. The applicability of each processing strategy is judged by the range of existence of the solution, in terms of melt volume and the values of the axial and radial temperature gradients in the crystal.

  3. OPTICAL DIAGNOSTIC AND MODELING SOLUTION GROWTH PROCESS OF SODIUM CHLORATE CRYSTALS

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; DUAN Li

    2006-01-01

    Both a real time optical interferometric experiment and a numerical simulation of two-dimension non-steady state model were employed to study the growth process of aqueous sodium chlorate crystals. The parameters such as solution concentration distribution, crystal dimensions, growth rate and velocity field were obtained by both experiment and numerical simulation. The influence of earth gravity during crystal growth process was analyzed. A reasonable theory model corresponding to the present experiment is advanced. The thickness of concentration boundary layer was investigated especially. The results from the experiment and numerical simulation match well.

  4. Cooling Before Super-Eruption: No Evidence of Rejuvenation in a Crystal-Rich Dacite Magma Body, Southern Great Basin Ignimbrite Province, Utah and Nevada

    Science.gov (United States)

    Ross, K. T.; Christiansen, E. H.; Best, M. G.; Dorais, M.

    2015-12-01

    rejuvenation from a near-solidus state. Instead, the magma was apparently cooling and crystallizing just prior to eruption.

  5. Simulation of Thermal Processes in Superconducting Pancake Coils Cooled by GM Cryocooler

    Science.gov (United States)

    Lebioda, M.; Rymaszewski, J.; Korzeniewska, E.

    2014-04-01

    This article presents the thermal model of a small scale superconducting magnetic energy storage system with the closed cycle helium cryocooler. The authors propose the use of contact-cooled coils with maintaining the possibility of the system reconfiguring. The model assumes the use of the second generation superconducting tapes to make the windings in the form of flat discs (pancakes). The paper presents results for a field model of the single pancake coil and the winding system consisting of several coils.

  6. Application of pyrolysis process to remove and recover liquid crystal and films from waste liquid crystal display glass.

    Science.gov (United States)

    Lu, Rixin; Ma, En; Xu, Zhenming

    2012-12-01

    Liquid crystal display (LCD) glass mainly consists of polarizing film, liquid crystal and glass substrate. Removing and recovering the liquid crystal and films from the LCD glass effectively has important significance for recovering the other parts. This study proposed a pyrolysis process to recover the organic parts from LCD glass. Through thermal gravimetric analysis, the pyrolysis temperature of the LCD glass could be chosen at 850 K. The removal rate of organic parts from LCD glass reached 87.87 wt%. Pyrolysis products consisted of 66.82 wt% oils, 21.01 wt% gaseous and 12.13 wt% residues. In addition, the oils contained 46.27 wt% acetic acid and 32.94 wt% triphenyl phosphate. Then, the pyrolysis mechanisms and products sources of the liquid crystal glass have been analyzed based on the information of bonds energy. The pyrolysis mechanism analysis proved that the products mainly consisted of acetic acid, triphenyl phosphate and C, which is consistent to the results of GC-MS analysis. A reasonable way has been put forward to recycle the pyrolysis products: acetic acid and triphenyl phosphate can be collected by distillation, the rest oils and gases can be used as fuel and the remained glass can be used to extract indium and to produce building materials.

  7. Fluid flow and solute segregation in EFG crystal growth process

    Science.gov (United States)

    Bunoiu, O.; Nicoara, I.; Santailler, J. L.; Duffar, T.

    2005-02-01

    The influence of the die geometry and various growth conditions on the fluid flow and on the solute distribution in EFG method has been studied using numerical simulation. The commercial FIDAP software has been used in order to solve the momentum and mass transfer equations in the capillary channel and in the melt meniscus. Two types of shaper design are studied and the results are in good agreement with the void distribution observed in rod-shaped sapphire crystals grown by the EFG method in the various configurations.

  8. Microstructure and Mechanical Properties of J55ERW Steel Pipe Processed by On-Line Spray Water Cooling

    Directory of Open Access Journals (Sweden)

    Zejun Chen

    2017-04-01

    Full Text Available An on-line spray water cooling (OSWC process for manufacturing electric resistance welded (ERW steel pipes is presented to enhance their mechanical properties and performances. This technique reduces the processing needed for the ERW pipe and overcomes the weakness of the conventional manufacturing technique. Industrial tests for J55 ERW steel pipe were carried out to validate the effectiveness of the OSWC process. The microstructure and mechanical properties of the J55 ERW steel pipe processed by the OSWC technology were investigated. The optimized OSWC technical parameters are presented based on the mechanical properties and impact the performance of steel pipes. The industrial tests show that the OSWC process can be used to efficiently control the microstructure, enhance mechanical properties, and improve production flexibility of steel pipes. The comprehensive mechanical properties of steel pipes processed by the OSWC are superior to those of other published J55 grade steels.

  9. Relationship between the magnetic field distribution and attractive force of single domain YBCO bulk under different field cooling processes

    Institute of Scientific and Technical Information of China (English)

    Yang Wan-Min; Zhou Lian; Feng Yong; Zhang Ping-Xiang; R. Nicolsky

    2004-01-01

    The levitation forces under different field cooling states were measured at 77K by changing the field cooling distance 0Zfc between a YBCO bulk and a permanent magnet. It is found that the relationship between the absolute maximum attractive force (Fmaf) and the corresponding gap distance (Zmaf) to Fmaf can be well described by exponential laws as a function of Zfc, which allow us to predict these values according to Zfc. It is also found that the distance between the Z0fa (gap distance corresponding to the zero force) and Zmaf in the ascending process is a constant value, which is closely related to the constant reduction factor of the axial component of flux density along the axial line of the magnet if Zmaf - Z0fa is a constant value. These results are very interesting for fundamental research and helpful in practical designing and applications.

  10. Economic analysis of wind-powered refrigeration cooling/water-heating systems in food processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Garling, W.S.; Harper, M.R.; Merchant-Geuder, L.; Welch, M.

    1980-03-01

    Potential applications of wind energy include not only large central turbines that can be utilized by utilities, but also dispersed systems for farms and other applications. The US Departments of Energy (DOE) and Agriculture (USDA) currently are establishing the feasibility of wind energy use in applications where the energy can be used as available, or stored in a simple form. These applications include production of hot water for rural sanitation, heating and cooling of rural structures and products, drying agricultural products, and irrigation. This study, funded by USDA, analyzed the economic feasibility of wind power in refrigeration cooling and water heating systems in food processing plants. Types of plants included were meat and poultry, dairy, fruit and vegetable, and aquaculture.

  11. A Low-Cost System Based on Image Analysis for Monitoring the Crystal Growth Process

    Directory of Open Access Journals (Sweden)

    Fabrício Venâncio

    2017-05-01

    Full Text Available Many techniques are used to monitor one or more of the phenomena involved in the crystallization process. One of the challenges in crystal growth monitoring is finding techniques that allow direct interpretation of the data. The present study used a low-cost system, composed of a commercial webcam and a simple white LED (Light Emitting Diode illuminator, to follow the calcium carbonate crystal growth process. The experiments were followed with focused beam reflectance measurement (FBRM, a common technique for obtaining information about the formation and growth of crystals. The images obtained in real time were treated with the red, blue, and green (RGB system. The results showed a qualitative response of the system to crystal formation and growth processes, as there was an observed decrease in the signal as the growth process occurred. Control of the crystal growth was managed by increasing the viscosity of the test solution with the addition of monoethylene glycol (MEG at 30% and 70% in a mass to mass relationship, providing different profiles of the RGB average curves. The decrease in the average RGB value became slower as the concentration of MEG was increased; this reflected a lag in the growth process that was proven by the FBRM.

  12. Crystal Plasticity Modeling of Microstructure Evolution and Mechanical Fields During Processing of Metals Using Spectral Databases

    Science.gov (United States)

    Knezevic, Marko; Kalidindi, Surya R.

    2017-05-01

    This article reviews the advances made in the development and implementation of a novel approach to speeding up crystal plasticity simulations of metal processing by one to three orders of magnitude when compared with the conventional approaches, depending on the specific details of implementation. This is mainly accomplished through the use of spectral crystal plasticity (SCP) databases grounded in the compact representation of the functions central to crystal plasticity computations. A key benefit of the databases is that they allow for a noniterative retrieval of constitutive solutions for any arbitrary plastic stretching tensor (i.e., deformation mode) imposed on a crystal of arbitrary orientation. The article emphasizes the latest developments in terms of embedding SCP databases within implicit finite elements. To illustrate the potential of these novel implementations, the results from several process modeling applications including equichannel angular extrusion and rolling are presented and compared with experimental measurements and predictions from other models.

  13. Development of Auto-Seeding System Using Image Processing Technology in the Sapphire Crystal Growth Process via the Kyropoulos Method

    Directory of Open Access Journals (Sweden)

    Churl Min Kim

    2017-04-01

    Full Text Available The Kyropoulos (Ky and Czochralski (Cz methods of crystal growth are used for large-diameter single crystals. The seeding process in these methods must induce initial crystallization by initiating contact between the seed crystals and the surface of the melted material. In the Ky and Cz methods, the seeding process lays the foundation for ingot growth during the entire growth process. When any defect occurs in this process, it is likely to spread to the entire ingot. In this paper, a vision system was constructed for auto seeding and for observing the surface of the melt in the Ky method. An algorithm was developed to detect the time when the internal convection of the melt is stabilized by observing the shape of the spoke pattern on the melt material surface. Then, the vision system and algorithm were applied to the growth furnace, and the possibility of process automation was examined for sapphire growth. To confirm that the convection of the melt was stabilized, the position of the island (i.e., the center of a spoke pattern was detected using the vision system and image processing. When the observed coordinates for the center of the island were compared with the coordinates detected from the image processing algorithm, there was an average error of 1.87 mm (based on an image with 1024 × 768 pixels.

  14. Phosphates (V) recovery from phosphorus mineral fertilizers industry wastewater by continuous struvite reaction crystallization process.

    Science.gov (United States)

    Hutnik, Nina; Kozik, Anna; Mazienczuk, Agata; Piotrowski, Krzysztof; Wierzbowska, Boguslawa; Matynia, Andrzej

    2013-07-01

    Continuous DT MSMPR (Draft Tube Mixed Suspension Mixed Product Removal) crystallizer was provided with typical wastewater from phosphorus mineral fertilizers industry (pH phosphate(V) ions decreased from 0.445 to 9.2 × 10(-4) mass %. This can be regarded as a very good process result. In product crystals, besides main component - struvite, all impurities from wastewater were detected analytically.

  15. Crystallization characteristics of cast aluminum alloys during a unidirectional solidification process

    Energy Technology Data Exchange (ETDEWEB)

    Okayasu, Mitsuhiro, E-mail: mitsuhiro.okayasu@utoronto.ca; Takeuchi, Shuhei

    2015-05-01

    The crystal orientation characteristics of cast Al–Si, Al–Cu and Al–Mg alloys produced by a unidirectional solidification process are examined. Two distinct crystal orientation patterns are observed: uniform and random formation. A uniform crystal orientation is created by columnar growth of α-Al dendrites in the alloys with low proportions of alloying element, e.g., the Al–Si alloy (with Si <12.6%) and the Al–Cu and Al–Mg alloys (with Cu and Mg <2%). A uniformly organized crystal orientation with [100] direction is created by columnar growth of α-Al dendrites. With increasing proportion of alloying element (>2% Cu or Mg), the uniform crystal orientations collapse in the Al–Cu and Al–Mg alloys, owing to interruption of the columnar α-Al dendrite growth as a result of different dynamics of the alloying atoms and the creation of a core for the eutectic phases. For the hypo-eutectic Al–Si alloys, a uniform crystal orientation is obtained. In contrast, a random orientation can be detected in the hyper-eutectic Al–Si alloy (15% Si), which results from interruption of the growth of the α-Al dendrites due to precipitation of primary Si particles. There is no clear effect of crystal formation on ultimate tensile strength (UTS), whereas crystal orientation does influence the material ductility, with the alloys with a uniform crystal orientation being elongated beyond their UTS points and with necking occurring in the test specimens. In contrast, the alloys with a nonuniform crystal orientation are not elongated beyond their UTS points.

  16. Crystallization Behavior of Virgin TR-55 Silicone Rubber Measured Using Dynamic Mechanical Thermal Analysis with Liquid Nitrogen Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Small IV, W; Wilson, T S

    2010-02-11

    Dynamic mechanical thermal analysis (DMTA) of virgin TR-55 silicone rubber specimens was conducted. Two dynamic temperature sweep tests, 25 to -100 C and 25 to -70 to 0 C (ramp rate = 1 C/min), were conducted at a frequency of 6.28 rad/s (1 Hz) using a torsion rectangular test geometry. A strain of 0.1% was used, which was near the upper limit of the linear viscoelastic region of the material based on an initial dynamic strain sweep test. Storage (G{prime}) and loss (G{double_prime}) moduli, the ratio G{double_prime}/G{prime} (tan {delta}), and the coefficient of linear thermal expansion ({alpha}) were determined as a function of temperature. Crystallization occurred between -40 and -60 C, with G{prime} increasing from {approx}6 x 10{sup 6} to {approx}4 x 10{sup 8} Pa. The value of {alpha} was fairly constant before ({approx}4 x 10{sup -4} mm/mm- C) and after ({approx}3 x 10{sup -4} mm/mm- C) the transition, and peaked during the transition ({approx}3 x 10{sup -3} mm/mm- C). Melting occurred around -30 C upon heating.

  17. Heat flow description during crystallization process of cast dispersive composites

    Directory of Open Access Journals (Sweden)

    Cholewa M.

    2007-01-01

    Full Text Available The aim of this work was to show possibilities of numerical simulation software, based on heat transfer model, commonly used in foundry industry in cast composite properties engineering. The main restriction in most of used software systems is lack of heat transfer, which may occur at composite creation. In this work the reinforcing particle morphology an size were expressed by one quantity – morphological modulus Mm and were examined for influence on heat transfer and conductivity up to the Newton’s and Fourier’s laws. The main restrictions for using Fourier’s model based software for composite engineering are shown. The way for crystallization control was presented including influence of morphology, transition zone and thermo-physical properties of components. Proposed methodology can be used for cast composite properties engineering in cases, where relative motion of components is negligible. In other cases heat transfer coefficient is justified only if the software used is based on Fourier’s model and the source code is accessible. Proposed assumptions create possibility for components selection verification in terms of technological and operating properties of cast composite. An example of such approach was shown in work [1, 23].

  18. 分步结晶工艺控制的改进探讨%The Improvement of Fractional Crystallization Process Control

    Institute of Scientific and Technical Information of China (English)

    王焕煜; 王仁远; 夏剑忠; 孙剑; 刘春法; 彭友山

    2012-01-01

    分步结晶工艺目前普遍采用的温度控制法的不足,主要是通过控制结晶器内导热介质慢速降温或升温来操作,对控制系统精度要求高,但不易有效控制结晶器结晶和发汗的速率。因此提出控制换热量直接控制结晶器的思路,并结合精萘生产实际,得到了较为完善的带散热补偿和工艺温差放大的换热速率-温度控制结晶器控制方案。新控制方案能精准稳定、直接有效地控制结晶和发汗速率,提高结晶分离效率,有较好的经济性,值得在分步结晶工艺中推广应用。%The shortages of temperature control method which has been widely used in fractional crystallization process include: It requires highly precise control systems because it works through controlling the heat conducting media cooling and heating in relatively slower rate,and it is hard to control crystallization or sweating rate effectively.A new method direct to control crystallizer by quantity of heat exchange has been proposed.It's called heat exchange-temperature control crystallizer,arising from industrial practice in the process of refined naphthalene,with well done heat dissipation compensator and temperature difference enlarge.The new control method could manipulate crystallization and sweating rate precisely,stably and effectively.The method could improve separation capacity and has good economic efficiency, deserving to be popularized in fractional crystallization process.

  19. Raman spectroscopic studies on the structural changes of poly(3-methylthiophene)during heating and cooling processes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Poly(3-methylthiophene) (PMeT) electrosynthesized by direct oxidation of 3-methylthiophene in boron trifluoride diethyl etherate (BFEE) has been studied by Raman spectroscopy in the temperature scale of 123-458 K. Experimental results demonstrate that the thermal stability of PMeT in the oxidized state is much lower than that of the polymer in the neutral state. Furthermore, during the cooling process, the conformation of neutral species changes from a coil-like state into a rod-like state, while the conformation of the oxidized species does not change.

  20. Modeling of the filling and cooling processes of hot fuel mains in Liquid Fuel Rocket Power Plant (LFRPP)

    Science.gov (United States)

    Prisnyakov, V. F.; Pokrishkin, V. V.; Serebryansky, V. N.

    A mathematical model of heat and mass exchange processes during filling and cooling of hot fuel mains of the Liquid Fuel Rocket Power Plant (LFRPP), which allows to define a mass consumption and distribution of two-phase flow parameters by the length of pipeline. Results of calculations are compared with experimental data, taken during filling of the main with a supply of liquid oxygen from the tank into the combustion chamber. Also, the results of modeling of hydrogen main dynamic characteristics of LFRPP in the same conditions are given.

  1. Fluoride-Salt-Cooled High-Temperature Reactor (FHR) for Power and Process Heat

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, Charles [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Hu, Lin-wen [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Peterson, Per [Univ. of California, Berkeley, CA (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-21

    In 2011 the U.S. Department of Energy through its Nuclear Energy University Program (NEUP) awarded a 3- year integrated research project (IRP) to the Massachusetts Institute of Technology (MIT) and its partners at the University of California at Berkeley (UCB) and the University of Wisconsin at Madison (UW). The IRP included Westinghouse Electric Company and an advisory panel chaired by Regis Matzie that provided advice as the project progressed. The first sentence of the proposal stated the goals: The objective of this Integrated Research Project (IRP) is to develop a path forward to a commercially viable salt-cooled solid-fuel high-temperature reactor with superior economic, safety, waste, nonproliferation, and physical security characteristics compared to light-water reactors. This report summarizes major results of this research.

  2. Effect of process parameters and crystal orientation on 3D anisotropic stress during CZ and FZ growth of silicon

    Science.gov (United States)

    Drikis, Ivars; Plate, Matiss; Sennikovs, Juris; Virbulis, Janis

    2017-09-01

    Simulations of 3D anisotropic stress are carried out in and oriented Si crystals grown by FZ and CZ processes for different diameters, growth rates and process stages. Temperature dependent elastic constants and thermal expansion coefficients are used in the FE simulations. The von Mises stress at the triple point line is 5-11% higher in crystals compared to crystals. The process parameters have a larger effect on the von Mises stress than the crystal orientation. Generally, the crystal has a higher azimuthal variation of stress along the triple point line ( 8%) than the crystal ( 2%). The presence of a crystal ridge increases the stress beside the ridge and decreases it on the ridge compared with the round crystal.

  3. Low Temperature Synthesis of Metal Oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process

    DEFF Research Database (Denmark)

    Jensen, Henrik; Brummerstedt Iversen, Steen; Joensen, Karsten Dan

    2006-01-01

    A novel method for producing crystalline nanosized metal oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process has been developed. The process is a modified sol-gel process taking place at temperatures as low as 95 ºC with supercritical CO2 as solvent and polypropylene as seeding....... The crystallinity can be controlled by changing the heating rate of the initial formation of the nanoparticles and the morphology can be altered by changing the process time....

  4. Cooling off with physics

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Chris [Unilever R and D (United Kingdom)

    2003-08-01

    You might think of ice cream as a delicious treat to be enjoyed on a sunny summer's day. However, to the ice-cream scientists who recently gathered in Thessaloniki in Greece for the 2nd International Ice Cream Symposium, it is a complex composite material. Ice cream consists of three dispersed phases: ice crystals, which have a mean size of 50 microns, air bubbles with a diameter of about 70 microns, and fat droplets with a size of 1 micron. These phases are held together by what is called the matrix - not a sci-fi film, but a viscous solution of sugars, milk proteins and polysaccharides. The microstructure, and hence the texture that you experience when you eat ice cream, is created in a freezing process that has remained fundamentally unchanged since the first ice-cream maker was patented in the 1840s. The ingredients - water, milk protein, fat, sugar, emulsifiers, stabilizers, flavours and a lot of air - are mixed together before being pasteurized and homogenized. They are then pumped into a cylinder that is cooled from the outside with a refrigerant. As the mixture touches the cylinder wall it freezes and forms ice crystals, which are quickly scraped off by a rotating blade. The blade is attached to a beater that disperses the ice crystals into the mixture. At the same time, air is injected and broken down into small bubbles by the shear that the beater generates. As the mixture passes along the cylinder, the number of ice crystals increases and its temperature drops. As a result, the viscosity of the mixture increases, so that more energy input is needed to rotate the beater. This energy is dissipated as heat, and when the ice cream reaches about -6 deg. C the energy input through the beater equals the energy removed as heat by the refrigerant. The process therefore becomes self-limiting and it is not possible to cool the ice cream any further. However, at -6 deg. C the microstructure is unstable. The ice cream therefore has to be removed from the freezer

  5. Measuring the coolness of interactive products: the COOL questionnaire

    DEFF Research Database (Denmark)

    Bruun, Anders; Raptis, Dimitrios; Kjeldskov, Jesper;

    2016-01-01

    is the COOL questionnaire. We based the creation of the questionnaire on literature suggesting that perceived coolness is decomposed to outer cool (the style of a product) and inner cool (the personality characteristics assigned to it). In this paper, we focused on inner cool, and we identified 11 inner cool......, rebelliousness and usability. These factors and their underlying 16 question items comprise the COOL questionnaire. The whole process of creating the questionnaire is presented in detail in this paper and we conclude by discussing our work against related work on coolness and HCI....

  6. Non-isothermal crystallization kinetics of polyethylene–clay nanocomposites prepared by high-energy ball milling

    Indian Academy of Sciences (India)

    Maryam Abareshi; Seyed Mojtaba Zebarjad; Elaheh K Goharshadi

    2014-08-01

    Non-isothermal crystallization kinetics of pure medium density polyethylene (MDPE) and MDPE–clay nanocomposites have been investigated by differential scanning calorimeter. The modified Avrami, Ozawa, Liu and Ziabicki equations have been applied to describe non-isothermal crystallization process. The results of Avrami analysis showed a very complicated crystallization mechanism. Although, Ozawa equation failed to provide an adequate description for non-isothermal crystallization process, Liu equation could describe it well. The data showed the crystallization rate of MDPE and nanocomposites raises with increasing cooling rate and the crystallization rate of nanocomposite is faster than that of MDPE at a given cooling rate. Ziabicki’s kinetic crystallizability index showed that clay can increase the ability of MDPE to crystallize, when it is cooled at unit cooling rate. The activation energy of samples has been evaluated by Kissinger method. The results showed that the activation energy of nanocomposite was lower than that of MDPE.

  7. Additives effects on crystallization and morphology in a novel caustic aluminate solution decomposition process

    Institute of Scientific and Technical Information of China (English)

    Ying ZHANG; Sbili ZHENG; Yifei ZHANG; Hongbin XU; Yi ZHANG

    2009-01-01

    A novel process of caustic aluminate solution decomposition by alcohol medium was developed by the Institute of Process Engineering, Chinese Academy of Sciences in order to solve the problem of low decomposi-tion ratio in the traditional Bayer seeded hydrolysis process. In this research, effects of additives on the crystallization ratio, secondary particle size and morphol-ogy of aluminum hydroxide in the new process were studied to obtain high-quality products. On the basis of primary selection of additives, an orthogonal design L9(34)was used as a chemometric method to investigate the effects of additives. The studied parameters include the reaction style, quantity of additives, caustic soda concen-tration, as well as the combination manner. The crystal-lization ratios of sodium aluminate solution and crystal size of aluminum hydroxide, determined by ICP-OES, SEM and MLPSA (Malvern Laser Particle Size Analyzer), were used to evaluate the effects of the additives. The results showed that different combination manners could promote agglomeration or dispersion. An additive composed by Tween 80 and PEG 200 could promote agglomeration,while a spot of PEG species had a relatively strong dispersion effect. However, the additives had little effects on the crystallization ratios. According to the Raman spectra result, the added alcohol medium might serve as a kind of solvent.

  8. On-line digital holographic measurement of size and shape of microparticles for crystallization processes

    Science.gov (United States)

    Khanam, Taslima; Darakis, Emmanouil; Rajendran, Arvind; Kariwala, Vinay; Asundi, Anand K.; Naughton, Thomas J.

    2008-09-01

    Crystallization is a widely used chemical process that finds applications in pharmaceutical industries. In an industrial crystallization process, it is not only important to produce pure crystals but also to control the shape and size of the crystals, as they affect the efficiency of downstream processes and the dissolution property of the drug. The effectiveness of control algorithms depend on the availability of on-line, real-time information about these critical properties. In this paper, we investigate the use of lens-less in-line digital holographic microscopy for size and shape measurements for crystallization processes. For this purpose, we use non-crystalline spherical microparticles and carbon fibers with known sizes present in a liquid suspension as test systems. We propose an algorithm to extract size and shape information for a population of microparticles from the experimentally recorded digital holograms. The measurements obtained from the proposed method show good agreement with the corresponding known size and shape of the particles.

  9. TEM study of the cooling rate dependent crystallization behavior of (Zr{sub 65}Al{sub 10}Ni{sub 10}Cu{sub 15}){sub 98}Nb{sub 2} metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingmin, E-mail: apwangym@dlut.edu.c [School of Materials Science and Engineering, Dalian University of Technology, No. 2 Lingggong Road, Ganjingzi District, Dalian, Liaoning 116024 (China); Shek, Chan Hung [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Wang, Qing; Qiang, Jianbing; Dong, Chuang [School of Materials Science and Engineering, Dalian University of Technology, No. 2 Lingggong Road, Ganjingzi District, Dalian, Liaoning 116024 (China)

    2010-08-15

    The crystallization of (Zr{sub 65}Al{sub 10}Ni{sub 10}Cu{sub 15}){sub 98}Nb{sub 2} metallic glasses has been studied using transmission electron microscopy (TEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The ribbon glass and bulk metallic glass (BMG) of this alloy exhibit different crystallization behaviors. For ribbon glass in the first stage crystallization, icosahedral quasicrystal (I-phase) precipitated together with the {eta}-Zr{sub 2}Ni (a = 1.226 nm) phase. The BMG alloy transforms into the I-phase and two coherently coexisted phases, namely, the Al{sub 2}Zr{sub 3} phase and an unknown primitive cubic phase (a = 0.76 nm) in this stage. The experimental evidence indicates that the liquid cooling rate for sample preparation has a significant effect on its crystallization behavior of this alloy glass.

  10. Monitoring the evolution of crystallization processes by in-situ solid-state NMR spectroscopy.

    Science.gov (United States)

    Harris, Kenneth D M; Hughes, Colan E; Williams, P Andrew

    2015-02-01

    Crystallization processes play a crucial role in many aspects of biological and physical sciences. Progress in deepening our fundamental understanding of such processes relies, to a large extent, on the development and application of new experimental strategies that allow direct in-situ monitoring of the process. In this paper, we give an overview of an in-situ solid-state NMR strategy that we have developed in recent years for monitoring the time-evolution of different polymorphic forms (or other solid forms) that arise as the function of time during crystallization from solution. The background to the strategy is described and several examples of the application of the technique are highlighted, focusing on both the evolution of different polymorphs during crystallization and the discovery of new polymorphs.

  11. Optimization of process parameters by Taguchi robust design method for the development of nano-crystals of sirolimus using sonication based crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, P.J.; Murthy, Z.V.P. [Chemical Engineering Department, S.V. National Institute of Technology, Surat, Gujarat (India); Pati, R.K. [Quantitative Methods and Operations Management, Indian Institute of Management, Kozhikode, Kerala (India)

    2012-01-15

    Taguchi method is widely used by the engineers and researchers across the globe for optimization of process parameters in view of cost, economy and time. Ultrasound based sonication process was used for deriving the nano-crystals of sirolimus in a narrow range. Seven critical process parameters with three levels were optimized with L{sub 18} array design. Crystal size analysis with its zeta potential measured and found that the crystals derived are stable in nature. Also SEM analysis carried out to know size and shape of the crystals and found that the crystals obtained are spherical in nature. Purity of the crystals derived checked with the help of melting point, TLC and HPLC procedures. Characterization of nano-crystals made with Fourier transform infrared spectroscopy and X-ray diffraction analysis. Correlation between the zeta potential and crystal size has been established with the help of scientific and statistical methods. Detailed statistical analysis such as t -test, regression and descriptive statistics of the results has been carried out to explore further information and interactions of process parameters. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Crystallization of Nanocomposite Glasses Made by the SSG Process

    Science.gov (United States)

    1989-08-31

    Silica Glass. Structurally diphasic gels of SiO 2 were prepared using cabosil (ultrafine "glassy" SiO2 powder) and crystalline seeds of cristobalite ...The triphasic gel was prepared by combining colloidal suspensions and proceeded by the formation of spinel and cristobalite followed by reaction to a... Preparation and Densification of Forsterite (MgISiO 4) 8v Nanocomposite Sol-Gel Processing------------------------ ---------- 49 Manuscript #4: Sol/Gel

  13. Crystal-field effects in fluoride crystals for optical refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Hehlen, Markus P [Los Alamos National Laboratory

    2010-01-01

    The field of optical refrigeration of rare-earth-doped solids has recently seen an important breakthrough. The cooling of a YLiF{sub 4} (YLF) crystal doped with 5 mol% Yb3+ to 155 K by Seletskiy et al [NPhot] has surpassed the lowest temperatures ({approx}170 K for {approx}100 mW cooling capacity) that are practical with commercial multi-stage thermoelectric coolers (TEC) [Glaister]. This record performance has advanced laser cooling into an application relevant regime and has put first practical optical cryocoolers within reach. The result is also relevant from a material perspective since for the first time, an Yb3+-doped crystal has outperformed an Yb3+-doped glass. The record temperature of 208 K was held by the Yb3+-doped fluorozirconate glass ZBLAN. Advanced purification and glass fabrication methods currently under development are expected to also advance ZBLAN:Yb3+ to sub-TEC temperatures. However, recent achievements with YLF:Yb3+ illustrate that crystalline materials may have two potentially game-changing advantajes over glassy materials. First, the crystalline environment reduces the inhomogeneous broadening of the Yb3+ electronic transitions as compared to a glassy matrix. The respective sharpening of the crystal-field transitions increases the peak absorption cross section at the laser excitation wavelength and allows for more efficient pumping of the Yb3+ ions, particularly at low temperatures. Second, many detrimental impurities present in the starting materials tend to be excluded from the crystal during its slow growth process, in contrast to a glass where all impurities present in the starting materials are included in the glass when it is formed by temperature quenching a melt. The ultra high purity required for laser cooling materials [PRB] therefore may be easier to realize in crystals than in glasses. Laser cooling occurs by laser excitation of a rare-earth ion followed by anti-Stokes luminescence. Each such laser-cooling cycle extracts

  14. 注射模冷却过程 CAE技术%The CAE Technology for the Cooling Process of Injection Moulds

    Institute of Scientific and Technical Information of China (English)

    申长雨; 陈静波; 刘春太; 李倩

    2001-01-01

    注射模冷却系统设计直接影响到塑件的生产效率和质量,冷却过程 CAE技术可预测出冷却介质的流动状态、模壁的温度、热流分布及冷却时间等,为设计人员评估设计方案,优化冷却系统设计提供了先进实用的工具。并简要介绍了注射模冷却过程 CAE技术的基本原理及在注射模冷却系统设计中的应用。%The design of the cooling system of injection moulds directly affects the production efficiency and quality of the injected parts. The CAE technology for the cooling process could predict the flowing status of the cooling medium, the temperature of the cavity wall, the distribution of the heat flow and the cooling time, etc. It provides for the designers with advanced and practical tool to evaluate the design scheme and optimize the design of the cooling system. And a brief introduction was made on the basic principle of the CAE technology for the cooling process of injection moulds and its application in the design of the cooling system.

  15. Process Parameters of Manufacturing Single Crystal Copper by Heated Mold Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    XU Guangji; DING Zongfu; DING Yutian; KOU Shengzhong; LIU Guanglin; LI Wei

    2005-01-01

    The effect of process parameters on the surface quality of single crystal copper ingot was studied through experiment with a self-designed horizontal heated mould continuous casting apparatus, and the mechanism was analyzed. The results show that the process parameters affect the surface quality of pure copper ingot by affecting the position of the liquid-solid interface in the mould. The position of the liquid-solid interface in the mould must be controlled carefully in an appropriate range determined through experiments in order to gain a single crystal copper ingot with a high surface quality.

  16. Laboratory Investigation of Contact Freezing and the Aerosol to Ice Crystal Transformation Process

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Raymond A. [Michigan Technological Univ., Houghton, MI (United States)

    2014-10-28

    This project has been focused on the following objectives: 1. Investigations of the physical processes governing immersion versus contact nucleation, specifically surface-induced crystallization; 2. Development of a quadrupole particle trap with full thermodynamic control over the temperature range 0 to –40 °C and precisely controlled water vapor saturation ratios for continuous, single-particle measurement of the aerosol to ice crystal transformation process for realistic ice nuclei; 3. Understanding the role of ice nucleation in determining the microphysical properties of mixed-phase clouds, within a framework that allows bridging between laboratory and field measurements.

  17. Influence of zone purification process on TlBr crystals for radiation detector fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Keitaro [Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai 982-8577 (Japan)], E-mail: hitomi@tohtech.ac.jp; Onodera, Toshiyuki; Shoji, Tadayoshi [Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai 982-8577 (Japan)

    2007-08-21

    Thallium bromide (TlBr) is a wide gap compound semiconductor and is a promising material for fabrication of nuclear radiation detectors. In this study, the conventional zone refining method was employed to reduce the concentration of impurities in the TlBr crystals. In order to evaluate the efficiency of the zone purification, the zone purification process was repeated up to 300 times. The resistivity, the charge transport properties, and the spectroscopic performance of TlBr detectors fabricated from the crystals zone purified 1 time, 100 times, and 300 times were compared in this study in order to clarify the effectiveness of the zone purification process.

  18. Influence of the cooling process on the sensory characteristics of fresh meat

    Energy Technology Data Exchange (ETDEWEB)

    Woltersdorf, W.

    1984-01-01

    Rapid temperature reduction for freshly-slaughtered animal carcasses or the meat from them is the best protection against the reproduction of microorganisms. Rapid temperature reduction increases durability in this way; moreover, these cold temperatures reduce the cooling-down times and the loss of substance in the meat which occurs due to water evaporation. The disadvantage of this rapid deep-freezing is the phenomenon of cold shortening (c.s.), an irreversible shortening effect on muscle fibres which results in toughness in the deep-frozen meat. For this reason a study has been made as to which sections of beef carcasses suffered c.s. at what freezing speed. Individual details of the testing procedure and characteristics studied (Temperature curve, ATP-content, pH value, tenderness, firmness, length of muscle fibrils, length of muscle) are given. The time-dependent freezing temperature curve of various sorts of beef was recorded in diagrams. Remarks are made on the way in which c.s. occurs and recommendations on how to prevent it are given. It was found that electrostimulation did not produce any extra tenderness effect when no c.s. is present.

  19. Formation and evolution properties of clusters in liquid metal copper during rapid cooling processes

    Institute of Scientific and Technical Information of China (English)

    YI Xue-hua; LIU Rang-su; TIAN Ze-an; HOU Zhao-yang; LI Xiao-yang; ZHOU Qun-yi

    2008-01-01

    Based on the quantum Sutton-Chen many-body potential, a molecular dynamics simulation was performed to investigate the formation and evolution properties of clusters in liquid Cu with 50 000 atoms. The cluster-type index method(CTIM) was used to describe the complex microstructure transitions. It is demonstrated that the amorphous structures are mainly formed with the three bond-types of 1551, 1541 and 1431 in the system, and the icosahedral cluster (12 0 12 0) and other basic polyhedron clusters of (12 2 8 2), (13 1 10 2), (13 3 6 4), (14 1 10 3), (14 2 8 4) and (14 3 6 5) play a critical and leading role in the transition from liquid to glass. The nano-clusters formed in the system consist of some basic clusters and middle cluster configurations by connecting to each other, and distinguish from those obtained by gaseous deposition and ionic spray. From the results of structural parameter pair distribution function g(r), bond-types and basic cluster-types, it is found that the glass transition temperature Tg for liquid metal Cu is about 673 K at the cooling rate of 1.0×1014 K/s.

  20. Optimization of intermediate cooling and intermediate heating in the gas turbine process; Optimierung der Zwischenkuehlung und der Zwischenerhitzung beim Gasturbinenprozess

    Energy Technology Data Exchange (ETDEWEB)

    Woerrlein, K.

    1998-07-01

    The author investigated how the thermal efficiency of the gas turbine process can be improved by intermediate cooling, intermediate heating, or combined intermediate cooling and heating. The focus was on the pressure ratios of low-pressure compressors and high-pressure turbines. The numeric calculations were carried out using real gas characteristics. The findings suggest that intermediate coling inside the compressor has much more influence on the thermal efficiency than intermediate heating inside the turbine. However, the latter is advantageous in the case of gas turbines for combined cycle operation, as the off-gas temperatures required for steam generation are reached even at relatively low turbine inlet temperatures, so that NOx emissions of the gas turbine combustion chamber will be low. It is recommended that solitary gas turbines should be operated with intermediate cooling and gas turbines in combined cycle operation with intermediate heating. [German] In der vorliegenden Arbeit soll untersucht werden, in welcher Weise sich der thermische Wirkungsgrad des Gasturbinen-Prozesses durch Zwischenkuehlung, Zwischenerhitzung bzw. Zwischenkuehlung und Zwischenerhitzung verbessern laesst. Dabei sollen in erster Linie die Druckverhaeltnisse von ND-Verdichter bzw. HD-Turbine bestimmt werden, bei denen Zwischenkuehlung und Zwischenerhitzung vorgenommen werden sollen, um eine optimale Verbesserung des thermischen Wirkungsgrades zu erreichen. Die numerische Durchrechnung soll mit den Stoffwerten des realen Gases durchgefuehrt werden. Die numerischen Ergebnisse zeigen, dass die Zwischenkuehlung im Verdichter einen weit groesseren Einfluss auf den thermischen Wirkungsgrad hat als die Zwischenerhitzung in der Turbine. Letztere ist aber bei Gasturbinen fuer den Kombibetrieb von Vorteil, erreicht man doch die fuer die Dampferzeugung notwendigen Abgastemperaturen der Gasturbine schon bei relativ niedrigen Turbineneintrittstemperaturen, so dass die NO{sub x}-Emission der

  1. Patterning technology for solution-processed organic crystal field-effect transistors

    Science.gov (United States)

    Li, Yun; Sun, Huabin; Shi, Yi; Tsukagoshi, Kazuhito

    2014-04-01

    Organic field-effect transistors (OFETs) are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development in patterning technology for solution-processed organic crystals and their applications in field-effect transistors. Typical demonstrations are discussed and examined. In particular, our latest research progress on the spin-coating technique from mixture solutions is presented as a promising method to efficiently produce large organic semiconducting crystals on various substrates for high-performance OFETs. This solution-based process also has other excellent advantages, such as phase separation for self-assembled interfaces via one-step spin-coating, self-flattening of rough interfaces, and in situ purification that eliminates the impurity influences. Furthermore, recommendations for future perspectives are presented, and key issues for further development are discussed.

  2. Patterning technology for solution-processed organic crystal field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yun Li

    2014-04-01

    Full Text Available Organic field-effect transistors (OFETs are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development in patterning technology for solution-processed organic crystals and their applications in field-effect transistors. Typical demonstrations are discussed and examined. In particular, our latest research progress on the spin-coating technique from mixture solutions is presented as a promising method to efficiently produce large organic semiconducting crystals on various substrates for high-performance OFETs. This solution-based process also has other excellent advantages, such as phase separation for self-assembled interfaces via one-step spin-coating, self-flattening of rough interfaces, and in situ purification that eliminates the impurity influences. Furthermore, recommendations for future perspectives are presented, and key issues for further development are discussed.

  3. Perspectives on integrated modeling of transport processes in semiconductor crystal growth

    Science.gov (United States)

    Brown, Robert A.

    1992-01-01

    The wide range of length and time scales involved in industrial scale solidification processes is demonstrated here by considering the Czochralski process for the growth of large diameter silicon crystals that become the substrate material for modern microelectronic devices. The scales range in time from microseconds to thousands of seconds and in space from microns to meters. The physics and chemistry needed to model processes on these different length scales are reviewed.

  4. Process induced disorder in crystalline materials: differentiating defective crystals from the amorphous form of griseofulvin.

    Science.gov (United States)

    Feng, Tao; Pinal, Rodolfo; Carvajal, M Teresa

    2008-08-01

    This research investigates milling induced disorder in crystalline griseofulvin. Griseofulvin was subjected to cryogenic milling for various lengths of time. For comparison, the amorphous form of griseofulvin was also prepared by the quench melt method. Different analytical techniques were used to study the differences between the cryomilled, amorphous and crystalline forms of the drug. Cryogenic milling of griseofulvin progressively reduces the crystallinity of the drug by inducing crystal defects, rather than amorphous materials. Raman analysis provides evidence of structural differences between the two. The differences between the defective crystals produced by milling and the amorphous form are significant enough as to be measurable in their bulk thermal properties. Defective crystals show significant decrease in the heat of fusion as a function of milling time but do not exhibit a glass transition nor recrystallization from the amorphous form. Crystal defects undergo recrystallization upon heating at temperatures well below the glass transition temperature (T(g)) in a process that is separate and completely independent from the crystallization of the amorphous griseofulvin, observed above T(g). Physical mixtures of defective crystals and amorphous drug demonstrate that the thermal events associated with each form persist in the mixtures, unaffected by the presence of the other form.

  5. Borassus flabellifer L. Brown Crystal Sugar Processing (The Study of Sap pH and Fine Crystal Sucrose (FCS Concentration

    Directory of Open Access Journals (Sweden)

    Azmi Alvian Gabriel

    2017-04-01

    Full Text Available Nira as one of the Borassus flabellirer L. products has a similar characteristics with other agricultural commodities that are easily damaged. This research aims to know the influence of nira’s pH and concentration addition of FCS against characteristics of the brown crystal sugar. Research compiled by using Randomized Block Design (RBD which comprises two factors consisting of 3 levels with 3 times replication. The first factor is pH or degree of nira acidity which consists of 3 level (6.50 (± 0.10; 7.00 (± 0.10; 7.50 (± 0.10 and the second factor is addition of FCS concentration consisting of 3 level (5%; 10%; 15% (b/v. The analyzes used include analysis of organoleptic (color, aroma, taste as well as physical and chemical analyzes (sucrose content, moisture content, ash content, reducing sugar content, insoluble solid content. The analysis results of raw material showed that the pH of palm sap affect the amount of total sugar because the fermentation process. The addition of 10% FCS provides organoleptic results with the best reception at the brown crystal sugar. Physical and chemical test results of products with the best treatment showed that the levels of sucrose in brown crystal sugar was 81.483% in accordance with the minimum requirements specified Indonesian Industrial Standard (IIS, water content of 6.32% dry basis , ash content of 1.78%, reducing sugar amounted to 5.18%, and insoluble solid content of 0.089%.

  6. Effect of dopant nanoparticles on reorientation process in polymer-dispersed liquid crystals

    Science.gov (United States)

    Zobov, K. V.; Zharkova, G. M.; Syzrantsev, V. V.

    2016-01-01

    The analysis of the experimental data of the nanoscale powders application for doping polymer-dispersed liquid crystals (PDLC) was represented in this work. A model based on the separation of the liquid crystals reorientation process on the surface mode and the volume mode was proposed and tested. In the research the wide-spread model mixture PDLC were used. But alumina nanoparticles were the distinctive ones obtained by electron beam evaporation. The proposed model allowed to conclude that the nanoparticles localization at the surface of the droplets (as in the Pickering emulsion) lead to the variation of the connection force between the liquid crystals and the polymer. The effect of nanoparticles resulted in an acceleration of the reorientation process near the surface when the control field is turned on and in a deceleration when it is turned off. The effect for the different size particles was confirmed.

  7. Some features of two commercial softwares for the modeling of bulk crystal growth processes

    Science.gov (United States)

    Santailler, J. L.; Duffar, T.; Théodore, F.; Boiton, P.; Barat, C.; Angelier, B.; Giacometti, N.; Dusserre, P.; Nabot, J. P.

    1997-10-01

    Two commercial codes, FIDAP and MARC, have been used to model a number of crystal growth processes in collaboration with industrial and research teams. Examples of global and local simulations in the field of heat transfer, hydrodynamics, chemistry and mechanics are given and the results are compared to experimental measurements, with good agreement as a rule. This establishes that such codes can be used to help improve crystal growth processes, while full global transient models still belong to software specifically written in order to model crystal growth. Emphasis is put on the necessity to validate the numerical results by comparison with experiments and to have a clear understanding of the physical laws hidden behind the software.

  8. Normal processes of phonon-phonon scattering and thermal conductivity of germanium crystals with isotopic disorder

    CERN Document Server

    Kuleev, I G

    2001-01-01

    The effect of normal processes of the phonon-phonon scattering on the thermal conductivity of the germanium crystals with various isotopic disorder degrees is considered. The phonon pulse redistribution in the normal scattering processes both inside each oscillatory branch (the Simons mechanism) and between various phonon oscillatory branches (the Herring mechanism) is accounted for. The contributions of the longitudinal and cross-sectional phonons drift motion into the thermal conductivity are analyzed. It is shown that the pulse redistribution in the Herring relaxation mechanism leads to essential suppression of the longitudinal phonons drift motion in the isotopically pure germanium crystals. The calculations results of thermal conductivity for the Herring relaxation mechanism agree well with experimental data on the germanium crystals with various isotopic disorder degrees

  9. Solar cell process development in the European integrated project CrystalClear

    Energy Technology Data Exchange (ETDEWEB)

    Beaucarne, G.; John, J.; Choulat, P.; Ma, Y. [IMEC vzw, Kapeldreef 75, B-3001 Leuven (Belgium); Russel, R. [BP Solar Espana, Madrid (Spain); Romijn, I.; Weeber, A. [ECN Solar Energy, PO Box 1, NL 1755 ZG Petten (Netherlands); Hofmann, M.; Preu, R. [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Slaoui, A. [InESS, Strassbourg (France); Le Quang, N.; Nichiporuk, O. [Photowatt Technologies, Bourgoin-Jallieu (France); Del Caoizo, C; Pan, A. [Polytechnical University of Madrid, Madrid (Spain); Solheim, H.; Evju, J. [REC Scancell, Sandvika (Norway); Nagel, H.; Horzel, J. [SCHOTT Solar, Alzenau (Germany); Bitnar, B.; Heemeier, M.; Weber, T. [SolarWorld, Freiberg/Sachsen (Germany); Raabe, B.; Haverkamp, H.; Struempel, C.; Junge, J.; Riegel, S.; Seren, S.; Hahn, G. [University of Konstanz, Department of Physics, P.O.Box X916, 78457 Konstanz (Germany)

    2008-10-15

    CrystalClear is a large integrated project funded by the European Commission that aims to drastically reduce the cost of crystalline Si PV modules, down to 1 Euro/Wp. Among the different subprojects, the one dealing with the development of advanced solar cells is relatively large (with 11 partners out of the 15 Crystal Clear partners taking part) and has a crucial role. The goal of the subproject is to develop cell design concepts and manufacturing processes that would enable a reduction in the order of 40% of the cell processing costs per Wp. In this paper, we give an overview of all the development work that has taken place in the CrystalClear solar cells subproject so far. World class results have been achieved, particularly on high efficiency cells on Si ribbons, and on industrial-type solar cells on very thin (120 {mu}m thick) substrates.

  10. Fuzzy algorithm used to water debit control to the secondary cooling in continuous casting process

    OpenAIRE

    Corina Cunţan; Ioan Baciu

    2005-01-01

    The relised research, reffering to human expert behaviar, show that this have a strong nonlinear behaviar, accompanied by prediction, integration, anticipation and delayed effects and even in adaptation of the real functioning process.The prominencing of languages caracterisation of process and also the interpretation based of experience in commands generation process represent the parameters which can modify the controll properties.The projected Fuzzy algorithms lead to nonlinear controllers...

  11. Unveiling the irreversible performance degradation of organo-inorganic halide perovskite films and solar cells during heating and cooling processes.

    Science.gov (United States)

    Mamun, Abdullah Al; Ava, Tanzila Tasnim; Byun, Hye Ryung; Jeong, Hyeon Jun; Jeong, Mun Seok; Nguyen, Loi; Gausin, Christine; Namkoong, Gon

    2017-07-26

    While organo-inorganic halide perovskite solar cells show great potential to meet future energy needs, their thermal instability raises serious questions about their commercialization viability. At present, the stability of perovskite solar cells has been studied under various environmental conditions including humidity and temperature. Nonetheless, understanding of the performance of CH3NH3PbI3-xClx perovskite solar cells is limited. This study reports the irreversible performance degradation of CH3NH3PbI3-xClx perovskite solar cells during the heating and cooling processes under AM 1.5 and unveils what triggers the irreversible performance degradation of solar cells. Particularly, the primary cause of the irreversible performance degradation of CH3NH3PbI3-xClx is quantitatively analyzed by monitoring in real time the development of deteriorated crystallinity, charge trapping/detrapping, trap depth, and the PbI2 phase, namely a critical signal of perovskite degradation while varying the temperature of the perovskite films and solar cells. Most surprisingly, it is revealed that the degradation of both perovskite films and solar cells was triggered at ∼70 °C. Remarkably, even after the device temperature cooled down to room temperature, the degraded performance of the solar cells persisted with increasing charge trapping and further development of the PbI2 phase. Identification of the irreversible performance degradation of perovskite solar cells provides guidance for future development of more stable perovskite solar cells.

  12. Intensified crystallization in complex media: heuristics for crystallization of platform chemicals

    NARCIS (Netherlands)

    Urbanus, J.; Roelands, C.P.M.; Verdoes, D.; Horst, J.H. ter

    2012-01-01

    This paper presents heuristics for the integration of fermentation with the appropriate crystallization based in-situ product recovery (ISPR) technique. Here techniques, such as co-crystallization (CC), evaporative crystallization (EC), template induced crystallization (TIC), cooling crystallization

  13. Intensified crystallization in complex media: heuristics for crystallization of platform chemicals

    NARCIS (Netherlands)

    Urbanus, J.; Roelands, C.P.M.; Verdoes, D.; Horst, J.H. ter

    2012-01-01

    This paper presents heuristics for the integration of fermentation with the appropriate crystallization based in-situ product recovery (ISPR) technique. Here techniques, such as co-crystallization (CC), evaporative crystallization (EC), template induced crystallization (TIC), cooling crystallization

  14. Cooling out in the Process of Track Placement of Students (An Example of Fatih/ Istanbul)

    Science.gov (United States)

    Yuksel, Asuman; Yuksel, Sedat

    2012-01-01

    Students graduating from elementary education are suggested to attend different kinds of high schools via track placement. According to conflict paradigm, this process is misleading and those students coming from low socioeconomic status are directed to vocational education instead of academical programs. In the process of track placement,…

  15. "Hot" Facilitation of "Cool" Processing: Emotional Distraction Can Enhance Priming of Visual Search

    Science.gov (United States)

    Kristjansson, Arni; Oladottir, Berglind; Most, Steven B.

    2013-01-01

    Emotional stimuli often capture attention and disrupt effortful cognitive processing. However, cognitive processes vary in the degree to which they require effort. We investigated the impact of emotional pictures on visual search and on automatic priming of search. Observers performed visual search after task-irrelevant neutral or emotionally…

  16. Electron cooling

    Science.gov (United States)

    Meshkov, I.; Sidorin, A.

    2004-10-01

    The brief review of the most significant and interesting achievements in electron cooling method, which took place during last two years, is presented. The description of the electron cooling facilities-storage rings and traps being in operation or under development-is given. The applications of the electron cooling method are considered. The following modern fields of the method development are discussed: crystalline beam formation, expansion into middle and high energy electron cooling (the Fermilab Recycler Electron Cooler, the BNL cooler-recuperator, cooling with circulating electron beam, the GSI project), electron cooling in traps, antihydrogen generation, electron cooling of positrons (the LEPTA project).

  17. Fuzzy algorithm used to water debit control to the secondary cooling in continuous casting process

    Directory of Open Access Journals (Sweden)

    Corina Cunţan

    2005-10-01

    Full Text Available The relised research, reffering to human expert behaviar, show that this have a strong nonlinear behaviar, accompanied by prediction, integration, anticipation and delayed effects and even in adaptation of the real functioning process.The prominencing of languages caracterisation of process and also the interpretation based of experience in commands generation process represent the parameters which can modify the controll properties.The projected Fuzzy algorithms lead to nonlinear controllers. To determine the controlling characteristics was used: Fuzzy Controller PIC 16C74, the appropriate software and ADA 3100 data acquisition board.To obtain a best controlling precision, the process was divided in two parts: start-stop and continuous casting process. For each part was establised the base rules and the membership functions which lead to obtain the controll surfaces and statical characteristics.

  18. Recovery of Nutrients from Struvite Crystallization process using Dairy Manure

    Directory of Open Access Journals (Sweden)

    T.SUVATHIKA

    2016-04-01

    Full Text Available Wastes collected from dairy farm are converted into manure by various processes for their application in agricultural fields in order to yield more production of crops. But unexpectedly the nutrient present in the manure is not completely utilized by the plants sometimes due to surface water runoff, floods and certain other aspects. The production of mineral fertilizers has a significant environmental impact, including depletion of fossil fuels and minerals. Therefore, the nutrients present in this manure comprise of minerals such as Magnesium, Ammonium and Phosphate which is otherwise called as struvite. This struvite can be precipitated separately and can be made as a substitute for manure since struvite is far rich in nutrients compared to manure and also it is considered as a slow releasing fertilizer which has less soluble in water. This thesis work shows the amount of MAP (Mg, Nh4, and P nutrients generated when Dairy manure is used as the influent to the fluidized bed reactor with addition of Mgcl which acts as a precipitating agent and also the impact of struvite precipitation in the concentration of total solids, hardness, pH, BOD/COD from the dairy wastewater is observed.

  19. Thermal and magnetic behaviors of a melt-textured superconducting bulk magnet in the zero-field-cooling magnetizing process

    Energy Technology Data Exchange (ETDEWEB)

    Oka, T [Faculty of Engineering, Niigata University, 8050 Ikarashi-Nino-cho, Nishi-ku, Niigata 950-2181 (Japan); Yokoyama, K [Ashikaga Department of Electrical and Electronic Engineering, Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi 326-8558 (Japan); Fujishiro, H; Noto, K [Faculty of Engineering, Iwate University, 3-4-5 Ueda, Morioka, Iwate 020-8551 (Japan)], E-mail: okat@eng.niigata-u.ac.jp

    2009-06-15

    The heat generation and magnetic field trapping behaviors of the melt-textured single-domain Sm-Ba-Cu-O bulk superconductor have been precisely investigated in the zero-field-cooling magnetizing processes (ZFC). The temperature and magnetic flux density were simultaneously measured in the temperature range of 50-60 K. Since the invasion of magnetic flux is suppressed by the superconducting pinning effect, the applied magnetic field is not supplied to the whole of the sample. Therefore, the trapped field distributions consequently exhibit trapezoid shapes. According to the balance of heat generation and draining, the temperature profiles show us distinctive behaviors of magnetic fluxes. Both the temperature and the magnetic flux density kept increasing even after the external magnetic field has stopped growing at 5 T. This is attributed to the flux creeping phenomenon which propagates from the periphery to the center portion of the sample like a snow slide. The highest temperature rise due to the flux motion reached 7.5 K even when the sample was magnetized at a slow sweeping rate of 5.06 mT s{sup -1}. As the temperature profiles were different between the ascending and descending field processes, it is suggested that the magnetic fluxes invade in and diffuse out in different heating manners between the processes. This assists the hypothesis that the time while the moving fluxes heat the sample strongly affects the total amount of heat generation, which acts contrary to the FC case. This behavior implies that the improvements of the heat propagation property of the HTS bulk material by embedding metallic membranes and more powerful/efficient cooling systems must suppress the temperature increases and enhance the field trapping abilities.

  20. Stochastic Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  1. Research of polishing process to control the iron contamination on the magnetorheological finished KDP crystal surface.

    Science.gov (United States)

    Chen, Shaoshan; Li, Shengyi; Peng, Xiaoqiang; Hu, Hao; Tie, Guipeng

    2015-02-20

    A new nonaqueous and abrasive-free magnetorheological finishing (MRF) method is adopted for processing a KDP crystal. MRF polishing is easy to result in the embedding of carbonyl iron (CI) powders; meanwhile, Fe contamination on the KDP crystal surface will affect the laser induced damage threshold seriously. This paper puts forward an appropriate MRF polishing process to avoid the embedding. Polishing results show that the embedding of CI powders can be avoided by controlling the polishing parameters. Furthermore, on the KDP crystal surface, magnetorheological fluids residua inevitably exist after polishing and in which the Fe contamination cannot be removed completely by initial ultrasonic cleaning. To solve this problem, a kind of ion beam figuring (IBF) polishing is introduced to remove the impurity layer. Then the content of Fe element contamination and the depth of impurity elements are measured by time of flight secondary ion mass spectrometry. The measurement results show that there are no CI powders embedding in the MRF polished surface and no Fe contamination after the IBF polishing process, respectively. That verifies the feasibility of MRF polishing-IBF polishing (cleaning) for processing a KDP crystal.

  2. Dielectric relaxation processes in smoky quartz crystals at very low temperatures

    NARCIS (Netherlands)

    Vos, W.J. de; Volger, J.

    1967-01-01

    The relaxation time governing the dielectric loss of smoky quartz crystals appears to level off as a function of temperature below 12°K, approaching a value of about 1 msec. The relaxational behaviour of the colour centres is discussed in terms of tunneling processes.

  3. Dielectric relaxation processes in smoky quartz crystals at very low temperatures

    NARCIS (Netherlands)

    Vos, W.J. de; Volger, J.

    1967-01-01

    The relaxation time governing the dielectric loss of smoky quartz crystals appears to level off as a function of temperature below 12°K, approaching a value of about 1 msec. The relaxational behaviour of the colour centres is discussed in terms of tunneling processes.

  4. A new investigation of dielectric relaxation processes in smoky quartz crystals

    NARCIS (Netherlands)

    Vos, W.J. de; Volger, J.

    1967-01-01

    Dielectric loss measurements on smoky quartz crystals over a wide frequency and temperature range (200 Hz-2.5 MHz and 20.4–160°K) showed, besides the well-known relaxation process at low temperatures, also a new relaxation mechanism, which becomes dominant above 100°K. There are strong arguments tha

  5. INVESTIGATION ON THE GELATION BEHAVIOR OF BIODEGRADABLE POLY(BUTYLENE SUCCINATE) DURING ISOTHERMAL CRYSTALLIZATION PROCESS

    Institute of Scientific and Technical Information of China (English)

    Fa-liang Luo; Xiu-qin Zhang; Wei Ning; Du-jin Wang

    2011-01-01

    The early stage of polymer crystallization may be viewed as physical gelation process, ie., the phase transition of polymer from liquid to solid. Determination of the gel point is of significance in polymer processing. In this work, the gelation behavior ofpoly(bntylene succinate) (PBS) at different temperatures has been investigated by theological method. It was found that during the isothermal crystallization process of PBS, both the storage modulus (G′) and the loss modulus (G")increase with time, and the theological response of the system varies from viscous-dominated (G′ < G") to elastic-dominated (G′ > G"), meaning the phase transition from liquid to solid. The physical gel point was determined by the intersection point of loss tangent curves measured under different frequencies. The gel time (tc) for PBS was found to increase with increasing crystallization temperature. The relative crystallinity of PBS at the gel point is very low (2.5%-8.5%) and increases with increasing the crystallization temperature. The low crystallinity of PBS at the gel point suggests that only a few junctions are necessary to form a spanning network, indicating that the network is “loosely” connected, in another word, the critical gel is soft. Due to the elevated crystallinity at gel point under higher crystallization temperature, the gel strength Sg increases,while the relaxation exponent n decreases with increasing the crystallization temperature. These experimental results suggest that rheological method is an effective tool for verifying the gel point of biodegradable semi-crystalline polymers.

  6. Non-classical crystallization of thin films and nanostructures in CVD and PVD processes

    CERN Document Server

    Hwang, Nong Moon

    2016-01-01

    This book provides a comprehensive introduction to a recently-developed approach to the growth mechanism of thin films and nanostructures via chemical vapour deposition (CVD). Starting from the underlying principles of the low pressure synthesis of diamond films, it is shown that diamond growth occurs not by individual atoms but by charged nanoparticles. This newly-discovered growth mechanism turns out to be general to many CVD and some physical vapor deposition (PVD) processes. This non-classical crystallization is a new paradigm of crystal growth, with active research taking place on growth in solution, especially in biomineralization processes. Established understanding of the growth of thin films and nanostructures is based around processes involving individual atoms or molecules. According to the author’s research over the last two decades, however, the generation of charged gas phase nuclei is shown to be the rule rather than the exception in the CVD process, and charged gas phase nuclei are actively ...

  7. N2 plasma etching processes of microscopic single crystals of cubic boron nitride

    Science.gov (United States)

    Tamura, Takahiro; Takami, Takuya; Yanase, Takashi; Nagahama, Taro; Shimada, Toshihiro

    2017-06-01

    We studied the N2 plasma etching of cubic boron nitride (cBN). We have developed experimental techniques for handling 200-µm-size single crystals for the preparation of surfaces with arbitrary crystal indexes, plasma processes, and surface analyses. We successfully prepared smooth surfaces of cBN with roughness smaller than 10 nm and found that the etching behavior was strongly influenced by the surface indexes. The morphology of the etched surfaces can be explained by the chemical stability of (111)B surfaces.

  8. Quantum-chemical approach to defect formation processes in non-metallic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kotomin, E.A.; Shluger, A.L. (Latvijskij Gosudarstvennyj Univ., Riga (USSR))

    1989-01-01

    Results of the quantum-chemical simulation of the formation of structural and radiation defects are reviewed, using ice, silicon, and silicon dioxide as examples. The relationship between the structural elements of these crystals and the structural defects is analysed. Models of the main defects, their optical characteristics, and the activation energy of their migration are discussed. The relationship between the characteristics obtained by quantum-chemical calculations and the parameters of the macroscopic kinetics of the processes induced by defects in dielectric crystals is considered. (author).

  9. Simulation study on the formation and transition properties of cluster structures in liquid metals during rapid cooling processes

    Institute of Scientific and Technical Information of China (English)

    郑采星; 刘让苏; 董科军; 彭平; 刘海蓉; 徐仲榆; 卢小勇

    2002-01-01

    For the first time, a molecular dynamics simulation study has been performed for a liquid metal system consisting of 50000 atoms to deeply investigate the transitions of microstructure configurations dudng the rapid cooling processes. Especially, the cluster-type index method has been adopted to analyze the transforming and evolving processes of clusters and cluster configurations from liquid metal atoms. It has been found that the bigger cluster configurations in the system are formed by means of connecting some small clusters (they are combined by several smaller clusters), and not taken on the multi-shells configuration accumulated with an atom as the center and the surrounding atoms arranged according to some fixed pattern. With the decrease in temperature, the probability of repetitive appearance for clusters increases largely, which reveals that clusters are indeed possessing a certain relative stability and continuity (namely hereditary effect). These results will give us an important enlightenment to understand not only the forming mechanisms and microscopic processes of the short-order sections and disorder sparse sections in amorphous structures but also the freezing processes of liquid metals.``

  10. Sublimation process and physical properties of vapor grown γ-In2Se3 platelet crystals

    Science.gov (United States)

    Ajayakumar, C. J.; Kunjomana, A. G.

    2016-11-01

    Indium selenide (γ-In2Se3) crystals have been grown by the closed tube sublimation process in the absence of seed crystals and chemical transporting agents. The composition, structure and morphology of the samples grown under different vacuum conditions were examined by energy dispersive analysis, X-ray diffraction, and scanning electron microscope. Structural features of the crystals obtained in a vacuum of 10-3 mbar exhibited a few reflections not belonging to γ phase, whereas X-ray diffraction spectra of the crystals deposited under a vacuum of 10-6 mbar revealed evidence of sharp peaks with high intensities of γ-In2Se3 crystalline phase. When growth runs were performed for 72 h, voids were observed on the surface whereas for a duration of 120 h, platelet crystals were obtained. Optical properties of these samples were investigated using the FT-IR and photoluminescence spectroscopy. The average transmittance of the platelets in the visible and near infrared region of solar spectrum was found to be ∼81% and an optical band gap of ∼2.05 eV was computed from the transmission spectrum. Photoluminescence spectra of the grown In2Se3 crystals recorded at room temperature using an excitation laser of wavelength 355 nm showed a peak in the near band edge emission (NBE) corresponding to an energy of 2.01 eV. Under an illumination power of 12 mW/cm2, the photocurrent increased linearly with applied voltage and the dark current was found to be 2.5×10-9 A for 10 V. These results suggest that the as-grown γ-In2Se3 platelets crystallized from vapor deposition, possess superior optoelectronic properties than the other phases for solar cell applications.

  11. Characteristics of indomethacin-saccharin (IMC-SAC) co-crystals prepared by an anti-solvent crystallization process.

    Science.gov (United States)

    Chun, Nan-Hee; Wang, In-Chun; Lee, Min-Jeong; Jung, Yun-Taek; Lee, Sangkil; Kim, Woo-Sik; Choi, Guang J

    2013-11-01

    The creation of co-crystals of various insoluble drug substances has been extensively investigated as a promising approach to improve their pharmaceutical performance. In this study, co-crystal powders of indomethacin and saccharin (IMC-SAC) were prepared by an anti-solvent (water) addition and compared with co-crystals by evaporation method. No successful synthesis of a pharmaceutical co-crystal powder via an anti-solvent approach has been reported. Among solvents examined, methanol was practically the only one that resulted in the formation of highly pure IMC-SAC co-crystal powders by anti-solvent approach. The mechanism of a preferential formation of IMC-SAC co-crystal to IMC was explained with two aspects: phase solubility diagram and solution complexation concept. Accordingly, the anti-solvent approach can be considered as a competitive route for producing pharmaceutical co-crystal powders with acceptable properties.

  12. Nonlinear processes upon two-photon interband picosecond excitation of PbWO4 crystal

    Science.gov (United States)

    Lukanin, V. I.; Karasik, A. Ya

    2016-09-01

    A new experimental method is proposed to study the dynamics of nonlinear processes occurring upon two-photon interband picosecond excitation of a lead tungstate crystal and upon its excitation by cw probe radiation in a temporal range from several nanoseconds to several seconds. The method is applied to the case of crystal excitation by a sequence of 25 high-power picosecond pulses with a wavelength of 523.5 nm and 633-nm cw probe radiation. Measuring the probe beam transmittance during crystal excitation, one can investigate the influence of two-photon interband absorption and the thermal nonlinearity of the refractive index on the dynamics of nonlinear processes in a wide range of times (from several nanoseconds to several seconds). The time resolution of the measuring system makes it possible to distinguish fast and slow nonlinear processes of electronic or thermal nature, including the generation of a thermal lens and thermal diffusion. An alternative method is proposed to study the dynamics of induced absorption transformation and, therefore, the dynamics of the development of nonlinear rocesses upon degenerate two-photon excitation of the crystal in the absence of external probe radiation.

  13. Effects of different cooling rates during two casting processes on the microstructures and mechanical properties of extruded Mg-Al-Ca-Mn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.W., E-mail: xushiwei@stn.nagaokaut.ac.jp [Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka 940-2188 (Japan); Oh-ishi, K.; Kamado, S.; Takahashi, H.; Homma, T. [Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka 940-2188 (Japan)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Ordered monolayer GP zone was formed by increasing cooling rate. Black-Right-Pointing-Pointer Finer extruded microstructure was obtained by increasing cooling rate. Black-Right-Pointing-Pointer Higher number density precipitates was obtained by increasing cooling rate. Black-Right-Pointing-Pointer Tensile 0.2% proof stress was increased by 105 MPa by increasing cooling rate. Black-Right-Pointing-Pointer Extruded DC-cast alloy shows higher tensile 0.2% proof stress of 409 MPa. - Abstract: In this study, Mg-3.6Al-3.4Ca-0.3Mn (wt.%) (which is denoted AXM4303) alloy ingots were prepared by two casting processes with different cooling rates: permanent mold (PM) casting, which has a lower cooling rate of 10-20 Degree-Sign C/s and direct chill (DC) casting, which has a higher cooling rate of 100-110 Degree-Sign C/s. Then, these two types of AXM4303 alloy ingots were hot extruded at 400 Degree-Sign C under the same conditions. The microstructures of the as-cast and extruded alloy samples were systematically investigated by field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) systems. The effects of the different cooling rates during the casting process on the microstructures and mechanical properties of the extruded AXM4303 alloy samples were evaluated. The results show that the strength of the extruded Mg-Al-Ca-Mn alloy can be substantially increased by microstructural control during the casting process. Because the cooling rate of the DC casting process is much faster than the cooling rate of PM casting, the DC-cast AXM4303 has the following properties: (i) the lamellar eutectic structure and dendrite cell size are significantly refined, (ii) the ordered monolayer GP zones enriched with Al and Ca nucleate with no growth, and (iii) most of the Mn remains in solution in the matrix. Thus, after hot extrusion, the DC-cast AXM4303 has finer

  14. Neural network model for the on-line monitoring of a crystallization process

    Directory of Open Access Journals (Sweden)

    Guardani R.

    2001-01-01

    Full Text Available This paper presents the results of the application of a recently developed technique, based on Neural Networks (NN, in the recognition of angular distribution patterns of light scattered by particles in suspension, for the purpose of estimating concentration and crystal size distribution (CSD in a precipitation process based on the addition of antisolvent (a model system consisting of sodium chloride, water and ethanol. In the first step, in NN model was fitted, using particles with different size distributions and concentrations. Then the model was used to monitor the process, thus enabling a fast and reliable estimation of supersaturation and CSD. Such information, which is difficult to obtain by any other means, can be used in the study of fundamental aspects of crystallization and precipitation processes.

  15. Development of specialized modelling tools for crystal growth processes with magnetic fields

    Science.gov (United States)

    Rudevics, A.; Muiznieks, A.; Nacke, B.

    2007-06-01

    The present paper is devoted to some aspects of the development of specialized software for the modelling of crystal growth processes with magnetic fields. Due to the complexity of the mathematical models for such processes, the modern technology of software design and implementation has to be used. Our experience in numerical modelling of crystal growth processes has shown that such approach facilitates the development of complex software systems. It involves the so-called object-oriented design and programming as well as the use of powerful software libraries in order to benefit from its functionality. To illustrate the programs created by our group, some examples are briefly described in this paper. Figs 7, Refs 13.

  16. Hydroxyl carboxylate based non-phosphorus corrosion inhibition process for reclaimed water pipeline and downstream recirculating cooling water system.

    Science.gov (United States)

    Wang, Jun; Wang, Dong; Hou, Deyin

    2016-01-01

    A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies (PRWS) and in downstream recirculating cooling water systems (RCWS) using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors (e.g., gluconate, citrate, tartrate) and zinc sulfate heptahydrate, which provided Zn(2+) as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate (which could be utilized as a corrosion inhibitor) content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS. Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4(3-) and Zn(2+) when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.

  17. Directed self-assembly lithography using coordinated line epitaxy (COOL) process

    Science.gov (United States)

    Seino, Yuriko; Kasahara, Yusuke; Sato, Hironobu; Kobayashi, Katsutoshi; Kubota, Hitoshi; Minegishi, Shinya; Miyagi, Ken; Kanai, Hideki; Kodera, Katsuyoshi; Kihara, Naoko; Kawamonzen, Yoshiaki; Tobana, Toshikatsu; Shiraishi, Masayuki; Nomura, Satoshi; Azuma, Tsukasa

    2015-03-01

    In this study, half-pitch (HP) 15 nm line-and-space (L/S) metal wires were successfully fabricated and fully integrated on a 300 mm wafer by applying directed self-assembly (DSA) lithography and pattern transfer for semiconductor device manufacturing. In order to evaluate process performances of DSA, we developed a simple sub-15 nm L/S patterning process using polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) lamellar block copolymer (BCP), which utilizes trimming resist and shallow etching spin-on-glass (SOG) as pinning guide[1]-[4]. From the results of defect inspection after SOG etch using Electron Beam (EB) inspection system, defects were classified as typical DSA defects or defects relating to DSA pattern transfer. From the evaluation of DSA L/S pattern Critical Dimension (CD), roughness and local placement error using CD-SEM, it is considered that isolated PS lines are placed at the centerline between guides and that placement of paired PS lines depends on the guide width. The control of the guide resist CD is the key to local placement error and the paired lines adjacent to the guide shifted toward the outside (0.5 nm) along the centerline of the isolated line after SOG etch. We demonstrated fabrication of HP 15 nm metal wires in trenches formed by the DSA process with reactive ion etching (RIE), followed by metal chemical vapor deposition (CVD) and chemical mechanical polishing (CMP). By SEM observation of alignment errors between the trenches and connect spaces, overlay shift patterns (-4 nm) in guide lithography mask were fabricated without intra-wafer alignment errors.

  18. Mixed Oxidant Process for Control of Biological Growth in Cooling Towers

    Science.gov (United States)

    2010-02-01

    Generation Process • Electrolysis of salt to generate chlorine biocides • Small-scale electrolytic cell generates biocide on site, on demand from a... copper , and copper coupons partially coated with 50%/50% tin lead solder Sodium hypo formed 5.7 times more lead and 1.4 times more copper than MOS...Corrosion rates of copper and mild steel corrosion coupons • Water Conditions – Total and free chlorine – Total hardness, calcium hardness – pH – Bioactivity

  19. Calculation of inelastic scattering processes of relativistic electrons in oriented crystals

    Energy Technology Data Exchange (ETDEWEB)

    Hinderks, Dieter; Kohl, Helmut

    2015-04-15

    The inelastic scattering of electrons in oriented crystals has been used to determine the positions of atoms within a crystal, to obtain site-dependent electron energy loss spectra and, more recently, to obtain an energy loss signal corresponding to the circular dichroism in X-ray absorption spectroscopy. The theoretical approaches currently used for the description of these processes are based on the nonrelativistic Schrödinger equation. Nowadays many experiments, however, are conducted with incident energies of 200 or 300 keV. Therefore it is indispensable to use a relativistic description for such processes based on the Dirac equation. Using the Coulomb gauge it is shown, that the fully relativistic cross sections for plane wave scattering are given by the modulus square of a sum of two terms: one describing the electrostatic interactions similar to the nonrelativistic theory plus one additional term describing the interaction of the specimen with the magnetic field produced by the incident electron. In crystals both terms can interfere leading to large deviations from nonrelativistic theory. - Highlights: • Inelastic scattering of relativistic electrons in oriented crystals is described. • We have derived equations for relativistic Bloch waves. • Strong deviations from nonrelativistic theory have been demonstrated.

  20. Non-isothermal Crystallization Kinetics of Kaolin Modified Polyester

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ruixin; GU Mingbo; CHEN Guoqiang

    2011-01-01

    Fiber-class modified kaolin and PET have been blended in the twin-screw and granulated to chips containing 4 wt% of kaolin.Non-isothermal crystallization process of kaolin modified polyester was investigated using a differential scanning calorimetry (DSC),and the addition of kaolin enhances either the melting temperature (Tm) or the crystallization temperature (Tc).The morphology of kaolin modified polyester,the melt of which is cooled at different cooling rate,was observed by scanning electron microscope (SEM).The relationship between Tc and cooling rate F was studied.Semi-crystalline phase t1/2 makes an exponential decline with increasing F,and the higher the cooling rate,the shorter the time of crystallization completion.Non-isothermal crystallization kinetics parameters and the activation energy were calculated,indicating that the higher rate of cooling needs the higher relative crystallinity in the unit crystallization time,the crystallization rate increased while speeding up the temperature reduction,and the activation energy AE was calculated to be -204.1566 kJ/mol for the non-isothermal crystallization processes by the Kissinger's methods.

  1. Properties of the Sodium Naproxen-Lactose-Tetrahydrate Co-Crystal upon Processing and Storage.

    Science.gov (United States)

    Sovago, Ioana; Wang, Wenbo; Qiu, Danwen; Raijada, Dhara; Rantanen, Jukka; Grohganz, Holger; Rades, Thomas; Bond, Andrew D; Löbmann, Korbinian

    2016-04-19

    Co-crystals and co-amorphous systems are two strategies to improve the physical properties of an active pharmaceutical ingredient and, thus, have recently gained considerable interest both in academia and the pharmaceutical industry. In this study, the behavior of the recently identified sodium naproxen-lactose-tetrahydrate co-crystal and the co-amorphous mixture of sodium, naproxen, and lactose was investigated. The structure of the co-crystal is described using single-crystal X-ray diffraction. The structural analysis revealed a monoclinic lattice, space group P21, with the asymmetric unit containing one molecule of lactose, one of naproxen, sodium, and four water molecules. Upon heating, it was observed that the co-crystal transforms into a co-amorphous system due to the loss of its crystalline bound water. Dehydration and co-amorphization were studied using synchrotron X-ray radiation and thermogravimetric analysis (TGA). Subsequently, different processing techniques (ball milling, spray drying, and dehydration) were used to prepare the co-amorphous mixture of sodium, naproxen, and lactose. X-ray powder diffraction (XRPD) revealed the amorphous nature of the mixtures after preparation. Differential scanning calorimetry (DSC) analysis showed that the blends were single-phase co-amorphous systems as indicated by a single glass transition temperature. The samples were subsequently tested for physical stability under dry (silica gel at 25 and 40 °C) and humid conditions (25 °C/75% RH). The co-amorphous samples stored at 25 °C/75% RH quickly recrystallized into the co-crystalline state. On the other hand, the samples stored under dry conditions remained physically stable after five months of storage, except the ball milled sample stored at 40 °C which showed signs of recrystallization. Under these dry conditions, however, the ball-milled co-amorphous blend crystallized into the individual crystalline components.

  2. Formation and Evolution of Non-dendritic Microstructures of Semisolid Alloys Prepared by Shearing/Cooling Roll Process

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The shearing/cooling roll (SCR) process was adopted to prepare semi-solid A2017 alloy. The formation and evolution of non-dendritic microstructures in semi-solid A2017 alloy were studied. It is shown that the microstructures of semi-solid billets transform from coarse dendrites into fine equiaxed grains as the pouring temperature of molten alloy decreases or roll-shoe cavity height is reduced. From the inlet to the exit of roll-shoe cavity, microstructure of semi-solid slurry near the shoe surface is in the order of coarse dendrites,degenerated dendrites or equiaxed grains, but fine equiaxed grains are near the roll surface. Microstructural evolution of semi-solid slurry prepared by SCR process is that the molten alloy nucleates and grows into dendrite firstly on the roll and shoe's surface. Under the shearing and stirring given by the rotating roll, the dendrites crush off and disperse into the melt. Under the shearing and stirring on semi-solid slurry with high volume fraction of solid, the dendrite arms fracture and form equiaxed grain microstructures.

  3. Microstructure Evolution in High Purity Aluminum Single Crystal Processed by Equal Channel Angular Pressing (ECAP).

    Science.gov (United States)

    Dong, Jinfang; Dong, Qing; Dai, Yongbing; Xing, Hui; Han, Yanfeng; Ma, Jianbo; Zhang, Jiao; Wang, Jun; Sun, Baode

    2017-01-22

    Aluminum single crystal with 99.999% purity was deformed at room temperature by equal channel angular pressing (ECAP) up to 16 passes. Grain size and misorientation of processed samples were quantitatively characterized by TEM and EBSD. The results show that the refinement efficiency of high purity aluminum single crystal was poor in the initial stage. Extrusion by fewer ECAP passes (n ≤ 8) resulted in only elongated grains containing a large number of subgrains and small misorientations between grains. Stable microstructures of nearly equiaxed grains with high misorientations were obtained by 15 passages, indicating that the initial extremely coarse grains and highly uniform grain orientation are not conducive to the accumulation of strain energy. The initial state of high purity aluminum has a significant effect on the refining efficiency of the ECAP process.

  4. Improvement of melt crystallization's efficiency for industrial applications. Final report 01-08-1990 - 31-03-1994

    NARCIS (Netherlands)

    Arkenbout, G.J.; Goede, R. de; Nienoord, M.; Verdoes, D.; Berg, E.P.G. van den; Geertman, R.; Bennema, P.; Neumann, M.; Ulrich, J.; Wellinghoff, G.; Kind, M.

    1994-01-01

    A research project was carried out by the University of Nijmegen, the University of Bremen, BASF and TNO to improve melt crystallization's efficienry in industrial applications. Both process options of growing crystal layers on the cooled wall of a heat exchanger and of growing crystals in suspensio

  5. Heat Transfer Process Computer Simulation and Microstructure Prediction During Crystallization of Metal Alloys

    Science.gov (United States)

    Georgiev, Georgi Evt.; Popov, Sasho; Manolov, Valentin; Dimitrova, Rositsa; Kuzmanov, Pavel

    2013-03-01

    Processes of crystallization during casting formation from aluminum alloys, steel and cast iron have been studied using 3-D com- puter simulation. Temperature fields of castings have been obtained and the microstructure distribution of these castings has been predicted. A comparison between numerical results and experimental measurement has been performed. It is proved, that the proposed approach is suitable for investigation and analysis of casting technologies.

  6. Effect of Processing Conditions on the Crystallization behavior and Destabilization Kinetics of Oil-in-Water Emulsions

    OpenAIRE

    Martini, Silvana; Tippetts, Megan

    2008-01-01

    The objective of this research was to systematically study the effect of processing conditions on the crystallization behavior and destabilization mechanisms of oil-in-water emulsions. The effect of crystallization temperature (T c) and homogenization conditions on both thermal behavior and destabilization mechanisms were analyzed. Results show that the crystallization of lipids present in the emulsions was inhibited when compared with bulk lipids as evidenced by a lower onset and peak temper...

  7. Silica photonic crystal fiber structure in order to simplify the process of making them

    Directory of Open Access Journals (Sweden)

    Ashkan Ghanbari

    2014-04-01

    Full Text Available In this research, a new structure of photonic crystal fibers(PCFs will be proposed,in which instead of using the aire- holes in the cladding region, the flourine(2% doped solid silica rods in order to reduce the problems associated with deformities of air-holes in the cladding region will be used.Also, in the following, a few of the propagation charactristics of the proposed Photonic Crystal Fiber with a conventional silica Photonic Crystal Fiber such as, Normalized frequency,effective refractive index,total dispersion and higher order dispersions ( Group velocity dispersion and Third Order Dispersion will be analyzed and compared. Finally it will be observed that, the proposed PCF structure is much simpler than the conventional one in the fabrication process. But they are not suitable for femtosecond solitons propagation .Also, it will be shown that, the situation of the conventional Photonic Crystal Fiber is much better than the proposed structure in the femtosecond optical solitons propagation.

  8. Design and optimization of production parameters for boric acid crystals with the crystallization process in an MSMPR crystallizer using FBRM® and PVM® technologies

    Science.gov (United States)

    Kutluay, Sinan; Şahin, Ömer; Ceyhan, A. Abdullah; İzgi, M. Sait

    2017-06-01

    In crystallization studies, newly developed technologies, such as Focused Beam Reflectance Measurement (FBRM) and Particle Vision and Measurement (PVM) are applied for determining on-line monitoring of a representation of the Chord Length Distribution (CLD) and observe the photographs of crystals respectively; moreover recently they are widely used. Properly installed, the FBRM ensures on-line determination of the CLD, which is statistically associated to the Crystal Size Distribution (CSD). In industrial crystallization, CSD and mean crystal size as well as external habit and internal structure are important characteristics for further use of the crystals. In this paper, the effect of residence time, stirring speed, feeding rate, supersaturation level and the polyelectrolytes such as anionic polyacrylamide (APAM) and non-ionic polyacrylamide (NPAM) on the CLD as well as the shape of boric acid crystals were investigated by using the FBRM G600 and the PVM V819 probes respectively in an MSMPR (Mixed Suspension Mixed Product Removal) crystallizer. The CSD and kinetic data were determined experimentally using continuous MSMPR crystallizer running at steady state. The population density of nuclei, the nucleation rate and the growth rate were determined from the experimental population balance distribution when the steady state was reached.

  9. Stabilizing control of crystal size distribution in continuous crystallization processes; Renzoku shoseki purosesu ni okeru kessho ryukei bunpu no anteika seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Naito, K.; Sotowa, K.; Kano, M.; Hasebe, S.; Hashimoto, I. [Kyoto Univ. (Japan). Faculty of Engineering

    1998-03-01

    The sustained oscillation of the crystal size distribution (CSD) in continuous crystallization process is analyzed by simulation using a detailed model. CSD can not be used as a controlled variable because of its distributed nature. Therefore, the method of selecting representability indices for CSD and the stabilizing control of CSD based on those indices are investigated. A multi-loop scheme is proposed, wherein a system with the third moment of large crystal and the rate of product flow from the continuous crystallizer used as the controlled variable and the operating variable, respectively, is added to the SISO control system which employs microcrystal population density as the controlled variable and the microcrystal flow rate as the operating variable. The controlling performances of the newly proposed multi-loop scheme and the SISO control scheme are compared. It is confirmed that the proposed controlling method is effective when the constrain from the microcrystal flow rate is strict. 6 refs., 14 figs., 2 tabs.

  10. Crystallization Process of Protein Rv0731c from Mycobacterium Tuberculosis for a Successful Atomic Resolution Crystal Structure at 1.2 Angstrom

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang Cong

    2009-06-08

    Proteins are bio-macromolecules consisting of basic 20 amino acids and have distinct three-dimensional folds. They are essential parts of organisms and participate in every process within cells. Proteins are crucial for human life, and each protein within the body has a specific function, such as antibodies, contractile proteins, enzymes, hormonal proteins, structural proteins, storage proteins and transport proteins. Determining three-dimensional structure of a protein can help researchers discover the remarkable protein folding, binding site, conformation and etc, in order to understand well of protein interaction and aid for possible drug design. The research on protein structure by X-ray protein crystallography carried by Li-Wei Hung's research group in the Physical Bioscience Division at Lawrence Berkeley National Laboratory (LBNL) is focusing on protein crystallography. The research in this lab is in the process of from crystallizing the proteins to determining the three dimensional crystal structures of proteins. Most protein targets are selected from Mycobacterium Tuberculosis. TB (Tuberculosis) is a possible fatal infectious disease. By studying TB target protein can help discover antituberculer drugs, and find treatment for TB. The high-throughput mode of crystallization, crystal harvesting, crystal screening and data collection are applied to the research pipeline (Figure 1). The X-ray diffraction data by protein crystals can be processed and analyzed to result in a three dimensional representation of electron density, producing a detailed model of protein structure. Rv0731c is a conserved hypothetical protein with unknown function from Mycobacterium Tuberculosis. This paper is going to report the crystallization process and brief structure information of Rv0731c.

  11. Vitrification and Crystallization of Phase-Separated Metallic Liquid

    Directory of Open Access Journals (Sweden)

    Yun Cheng

    2017-02-01

    Full Text Available The liquid–liquid phase separation (LLPS behavior of Fe50Cu50 melt from 3500 K to 300 K with different rapid quenching is investigated by molecular dynamics (MD simulation based on the embedded atom method (EAM. The liquid undergoes metastable phase separation by spinodal decomposition in the undercooled regime and subsequently solidifies into three different Fe-rich microstructures: the interconnected-type structure is kept in the glass and crystal at a higher cooling rate, while the Fe-rich droplets are found to crystalize at a lower cooling rate. During the crystallization process, only Fe-rich clusters can act as the solid nuclei. The twinning planes can be observed in the crystal and only the homogeneous atomic stacking shows mirror symmetry along the twinning boundary. Our present work provides atomic-scale understanding of LLPS melt during the cooling process.

  12. Addition of superoxide dismutase mimics during cooling process prevents oxidative stress and improves semen quality parameters in frozen/thawed ram spermatozoa.

    Science.gov (United States)

    Santiani, Alexei; Evangelista, Shirley; Sepúlveda, Néstor; Risopatrón, Jennie; Villegas, Juana; Sánchez, Raúl

    2014-10-01

    High levels of reactive oxygen species (ROS), which may be related to reduced semen quality, are detected during semen cryopreservation in some species. The objectives of this study were to measure the oxidative stress during ram semen cryopreservation and to evaluate the effect of adding 2 antioxidant mimics of superoxide dismutase (Tempo and Tempol) during the cooling process on sperm motility, viability, acrosomal integrity, capacitation status, ROS levels, and lipid peroxidation in frozen and/or thawed ram spermatozoa. Measuring of ROS levels during the cooling process at 35, 25, 15, and 5 °C and after freezing and/or thawing showed a directly proportional increase (P ram spermatozoa are exposed to oxidative stress during the cooling process, specifically when maintained at 5 °C and that lipid peroxidation induced by high levels of ROS decreases sperm motility and induces premature sperm capacitation. In contrast, the addition of Tempo or Tempol at 0.5 to 1 mM during the cooling process (10 °C) protects ram spermatozoa from oxidative stress.

  13. Gas-cooled reactor commercialization study: introduction scenario and commercialization analyses for process heat applications. Final report, July 8, 1977--November 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    This report identifies and presents an introduction scenario which can lead to the operation of High Temperature Gas Cooled Reactor demonstration plants for combined process heat and electric power generation applications, and presents a commercialization analysis relevant to the organizational and management plans which could implement a development program.

  14. Cooperativity of the assembly process in a low concentration chromonic liquid crystal.

    Science.gov (United States)

    Mercado, Benjamin R; Nieser, Kenneth J; Collings, Peter J

    2014-11-20

    IR-806 is a near-infrared cyanine dye that undergoes a two-step assembly process in aqueous solutions. The final assemblies orientationally order into a liquid crystal at a very low concentration (∼0.6 wt % at room temperature). While the first step of the assembly process is continuous as the dye concentration or temperature is varied (isodesmic), the second step is more abrupt (cooperative). Because the absorption spectrum of IR-806 changes dramatically during the assembly process, careful equilibrium and kinetic absorption experiments are utilized to examine the details of the cooperative second step. These experiments involve changes in both concentration and temperature, allowing a close thermodynamic analysis of the assembly process. Both equilibrium and kinetic investigations reveal that the assembly process is highly cooperative and can be described by multiple models (for example, nucleation and growth) in the highly cooperative limit. The enthalpy associated with the growth process and the activation energy of the rate-limiting step during disassembly are determined. These findings have significant implications for the structure of the assemblies that form the liquid crystal phase in IR-806.

  15. The characteristic of crystal growth of Nd–Fe–B cast strips during the rapid solidification process

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingdai, E-mail: wangjingdai2015@126.com; Meng, Yu; Zhang, Huaxia; Tang, Hui; Lin, Rongbing; Sun, Chuanqi; Wu, Changxin; Xie, Fayin

    2015-12-15

    The microstructure of Nd–Fe–B cast strips with different thickness was investigated intensively. The cooling rate decreased with increasing thickness of the cast strips. When the thickness was more than 0.5 mm, α-Fe precipitated in the free side of the strips because the cooling rate was too low. However, the nucleation rate increased with increasing thickness. When the thickness was more than 0.5 mm, a layer of fine equiaxed grains formed near the wheel side. With the increased thickness, the volume fraction of columnar grain increased to maximum (91%) at 0.3 mm and then decreased. The characteristic of crystal growth of Nd–Fe–B cast strips with different thickness during solidification was discussed. - Highlights: • The cooling rate decreased with increasing thickness of the cast strips. • α-Fe precipitated in the free side of the strips with thickness more than 0.5 mm. • Fine equiaxed grains formed in the strips with thickness more than 0.5 mm. • The volume fraction of columnar grain increased to 91% at 0.3 mm and then decreased. • A schematic diagram of the characteristic of the crystal growth was proposed.

  16. Magnetization Reversal Process of Single Crystal α-Fe Containing a Nonmagnetic Particle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi [Tsinghua Univ., Beijing (China); Tsinghua Univ., Shenzhen (China); Xu, Ben [Tsinghua Univ., Beijing (China); Hu, Shenyang Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Li, Yulan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Li, Qiu-Lin [Tsinghua Univ., Beijing (China); Tsinghua Univ., Shenzhen (China); Liu, Wei [Tsinghua Univ., Beijing (China); Tsinghua Univ., Shenzhen (China)

    2015-09-25

    The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz–Gilbert equation. The evolutions of the magnetic domain morphology are studied, and our analyses show that the magnetization reversal process is affected by the interaction between the moving domain wall and the existing nonmagnetic particles. This interaction strongly depends on the size of the particles, and it is found that particles with a particular size contribute the most to magnetic hardening.

  17. Demonstration of Crystal Structure.

    Science.gov (United States)

    Neville, Joseph P.

    1985-01-01

    Describes an experiment where equal parts of copper and aluminum are heated then cooled to show extremely large crystals. Suggestions are given for changing the orientation of crystals by varying cooling rates. Students are more receptive to concepts of microstructure after seeing this experiment. (DH)

  18. IR spectroscopy together with multivariate data analysis as a process analytical tool for in-line monitoring of crystallization process and solid-state analysis of crystalline product

    DEFF Research Database (Denmark)

    Pöllänen, Kati; Häkkinen, Antti; Reinikainen, Satu-Pia

    2005-01-01

    Crystalline product should exist in optimal polymorphic form. Robust and reliable method for polymorph characterization is of great importance. In this work, infra red (IR) spectroscopy is applied for monitoring of crystallization process in situ. The results show that attenuated total reflection...... Fourier transform infra red (ATR-FTIR) spectroscopy provides valuable information on process, which can be utilized for more controlled crystallization processes. Diffuse reflectance Fourier transform infra red (DRIFT-IR) is applied for polymorphic characterization of crystalline product using X...

  19. Growth of BPO4 single crystals from Li2Mo3O10 flux

    Science.gov (United States)

    Xu, Guogang; Li, Jing; Han, Shujuan; Guo, Yongjie; Wang, Jiyang

    2010-12-01

    Transparent single crystal of BPO4 with a typical sizes of 5 × 7 × 9 mm3 have been grown by the top-seeded solution growth (TSSG) slow-cooling method using Li2Mo3O10 as the flux. X-ray powder diffraction result shows that the as-grown crystal was well crystallized and indexed in a tetragonal system. The processing parameters and the effects of the flux on the crystal growth were investigated.

  20. Diode laser crystallization processes of Si thin-film solar cells on glass

    Directory of Open Access Journals (Sweden)

    Yun Jae Sung

    2014-07-01

    Full Text Available The crystallization of Si thin-film on glass using continuous-wave diode laser is performed. The effect of various processing parameters including laser power density and scanning speed is investigated in respect to microstructure and crystallographic orientation. Optimal laser power as per scanning speed is required in order to completely melt the entire Si film. When scan speed of 15–100 cm/min is used, large linear grains are formed along the laser scan direction. Laser scan speed over 100 cm/min forms relatively smaller grains that are titled away from the scan direction. Two diode model fitting of Suns-Voc results have shown that solar cells crystallized with scan speed over 100 cm/min are limited by grain boundary recombination (n = 2. EBSD micrograph shows that the most dominant misorientation angle is 60°. Also, there were regions containing high density of twin boundaries up to ~1.2 × 10-8/cm2. SiOx capping layer is found to be effective for reducing the required laser power density, as well as changing preferred orientation of the film from ⟨ 110 ⟩ to ⟨ 100 ⟩ in surface normal direction. Cracks are always formed during the crystallization process and found to be reducing solar cell performance significantly.

  1. Nucleation and crystallization process of silicon using Stillinger-Weber potential

    Science.gov (United States)

    Beaucage, Philippe; Mousseau, Normand

    2004-03-01

    Philippe Beaucage and Normand Mousseau Département de physique and RQMP, Université de Montréal We present a numerical study of the nucleation process leading to the crystallization of a 10648-atoms system. With elementary building blocks of diamond and wurtzite structure as a criterion for the recognition of the crystalline nuclei in the supercooled liquid, we can directly follow the phase transition. Out of the nine NVT trajectories we generate, six crystallizes in less than 10 ns. By following the trajectory of the stable cluster which will eventually nucleate, we can identify the different regimes of the nucleation process. The path to crystallization can also be analysed in terms of the classical nucleation theory (CNT). For example, the lifetime distribution of clusters as a function of their size is well represented by an inversed Gaussian, as can be derived from CNT. However, there are some strong discrepancies with the CNT predictions of the free energy curve. A number of hypotheses are studied to identify the source of this discrepancy. This work is supported in part by NSERC and FQRNT. NM is a Cottrell Scholar of the Research Corporation.

  2. Effect of field cooling process and ion-beam bombardment on the exchange bias of NiCo/(Ni, Co)O bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, X. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Lin, K.-W., E-mail: kwlin@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Liu, H.-Y. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Wei, D.-H. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Li, G.J. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Pong, P.W.T., E-mail: ppong@eee.hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong)

    2014-11-03

    The research on exchange coupled ferromagnetic/antiferromagnetic (FM/AF) bilayers has been the foundation of spintronic applications such as hard disk reading heads and spin torque oscillators. In order to further explore the exchange bias behavior of NiCo/(Ni, Co)O bilayers, effect of field cooling process, magnetic angular dependence, and ion-beam bombardment was investigated. The difference in film composition resulted in remarkable distinction in crystalline structures and domain patterns. The exchange bias field (H{sub ex}) in the bilayer systems exhibited a strong angular dependence. The negative H{sub ex} after a field cooling process indicated that the polarity of H{sub ex} can be defined by aligning the magnetization orientation of the FM NiCo layer with the applied field. Moreover, enhanced exchange bias effect was observed in the NiCo/(Ni, Co)O bilayers that resulted from the surface of the (Ni, Co)O layers bombarded with different Ar{sup +} ion-beam energies using End-Hall voltages from 0 V to 150 V. The interface spin structures as well as the surface domain patterns were altered by the ion-beam bombardment process. These results indicated that the exchange bias field of NiCo/(Ni, Co)O bilayer systems could be tailored by field cooling process, angular dependence of magnetic properties, and post ion-beam bombardment. - Highlights: • Strong angular dependence was observed in the exchange bias of NiCo/(Ni, Co)O bilayers. • The field cooling process resulted in negative exchange bias. • Moderate ion-beam bombardment on (NiCo)O layers enhanced exchange bias at 298 K. • High-energy ion bombardment strengthened the exchange coupling in field cooled bilayer. • The structural deformation was responsible for the change in magnetic properties.

  3. Electrochromic effect in domain-inversion process in LiNbO3: Ru: Fe crystals

    Institute of Scientific and Technical Information of China (English)

    XI Qingxin; LIU De'an; ZHI Ya'nan; ZHU Luan; LIU Liren

    2005-01-01

    A reversible electrochromic effect accompanying domain-inversion during the electrical poling process in LiNbO3: Ru: Fe crystals at room temperature has been observed. In electrode area, both electrochromism and domain-inversion occur alternately, and electrochromism is also reversible during back-switch poling, which is experimentally verified and whose mechanism is briefly explained using a microstructure ferroelectric model. In addition, because of the enhancing elcctrochromic effect, different from the undoped LiNbO3 crystals, the coercive filed (21.0 kV/mm or so) measured in LiNbO3: Ru: Fe is lower than its breakdown field, thus providing a possible new technique for realizing the domain-inversion by constant electric field rather than a pulsed one.

  4. Control of parabolic PDEs with time-varying spatial domain: Czochralski crystal growth process

    Science.gov (United States)

    Ng, James; Aksikas, Ilyasse; Dubljevic, Stevan

    2013-09-01

    This paper considers the optimal control problem for a class of convection-diffusion-reaction systems modelled by partial differential equations (PDEs) defined on time-varying spatial domains. The class of PDEs is characterised by the presence of a time-dependent convective-transport term which is associated with the time evolution of the spatial domain boundary. The functional analytic description of the PDE yields the representation of the initial and boundary value problem as a nonautonomous parabolic evolution equation on an appropriately defined infinite-dimensional function space. The properties of the time-varying evolution operator to guarantee existence and well posedness of the initial and boundary value problem are demonstrated which serves as the basis for the optimal control problem synthesis. An industrial application of the crystal temperature regulation problem for the Czochralski crystal growth process is considered and numerical simulation results are provided.

  5. Prospects of Wannier functions in investigating photonic crystal all-optical devices for signal processing.

    Science.gov (United States)

    Muradoglu, M S; Baghai-Wadji, A R; Ng, T W

    2010-04-01

    Wannier functions derived from Bloch functions have been identified as an efficient means of analyzing the properties of photonic crystals in which localized functions have now opened the door for 2D and 3D structures containing defects to be investigated. In this paper, based on the Maxwell equations in diagonalized form and utilizing Bloch waves we have obtained an equivalent system of algebraic equations in eigenform. By establishing and exploiting several distinct properties of the resulting eigenpairs, we demonstrate an ability to construct Wannier functions associated with the simplest one-dimensional photonic structure. More importantly, the numerical investigation of the inner- and intra-band orthonormality conditions as well as Hilbert space partitioning features shows a capability for multi-resolution analysis that will make all-optical signal processing devices with photonic crystal structures feasible.

  6. Hydrothermal activity in Tertiary Icelandic crust: Implication for cooling processes along slow-spreading mid-ocean ridges

    Science.gov (United States)

    Pałgan, D.; Devey, C. W.; Yeo, I. A.

    2015-12-01

    Known hydrothermal activity along the Mid-Atlantic Ridge is mostly high-temperature venting, controlled by volcano-tectonic processes confined to ridge axes and neotectonic zones ~15km wide on each side of the axis (e.g. TAG or Snake Pit). However, extensive exploration and discoveries of new hydrothermal fields in off-axis regions (e.g. Lost City, MAR) show that hydrothermalism may, in some areas, be dominated by off-axis venting. Little is known about nature of such systems, including whether low-temperature "diffuse" venting dominates rather than high-temperature black-smokers. This is particularly interesting since such systems may transport up to 90% of the hydrothermal heat to the oceans. In this study we use Icelandic hot springs as onshore analogues for off-shore hydrothermal activity along the MAR to better understand volcano-tectonic controls on their occurrence, along with processes supporting fluid circulation. Iceland is a unique laboratory to study how new oceanic crust cools and suggests that old crust may not be as inactive as previously thought. Our results show that Tertiary (>3.3 Myr) crust of Iceland (Westfjords) has widespread low-temperature hydrothermal activity. Lack of tectonism (indicated by lack of seismicity), along with field research suggest that faults in Westfjords are no longer active and that once sealed, can no longer support hydrothermal circulation, i.e. none of the hot springs in the area occur along faults. Instead, dyke margins provide open and permeable fluid migration pathways. Furthermore, we suggest that the Reykjanes Ridge (south of Iceland) may be similar to Westfjords with hydrothermalism dominated by off-axis venting. Using bathymetric data we infer dyke positions and suggest potential sites for future exploration located away from neotectonic zone. We also emphasise the importance of biological observations in seeking for low-temperature hydrothermal activity, since chemical or optical methods are not sufficient.

  7. A new technique for laser cooling with superradiance

    CERN Document Server

    Nemova, Galina

    2010-01-01

    We present a new theoretical scheme for laser cooling of rare earth doped solids with optical super-radiance (SR), which is the coherent, sharply directed spontaneous emission of photons by a system of laser excited rare earth ions in the solid state host (glass or crystal). We consider an Yb3+ doped ZBLAN sample pumped at the wavelength 1015 nm with a rectangular pulsed source with a power of ~433W and duration of 10ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits a dramatic increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare earth doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy hosts for laser cooling.

  8. Laser Cooling of Solids

    Science.gov (United States)

    2009-01-01

    observed in a range of glasses and crystals doped with Yb3+ (ZBLANP [19–22], ZBLAN [23,24], CNBZn [9,25] BIG [25, 26], KGd(WO4)2 [9], KY(WO4)2 [9], YAG [27...Yb3+-doped fluorozirconate glass ZBLAN , Phys. Rev. B 75, 144302 (2007). [40] C. W. Hoyt, Laser Cooling in Thulium-doped Solids, Ph. D. Thesis...date, optical refrigeration research has been confined to glasses and crystals doped with rare- earth elements and direct-band semiconductors such as

  9. Analysis of the adsorption process and of desiccant cooling systems: a pseudo- steady-state model for coupled heat and mass transfer. [DESSIM, DESSIM2, DESSIM4

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, R.S.

    1982-12-01

    A computer model to simulate the adiabatic adsorption/desorption process is documented. Developed to predict the performance of desiccant cooling systems, the model has been validated through comparison with experimental data for single-blow adsorption and desorption. A literature review on adsorption analysis, detailed discussions of the adsorption process, and an initial assessment of the potential for performance improvement through advanced component development are included.

  10. Extension of the classical theory of crystallization to non-isothermal regimes: Application to nanocrystallization processes

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez, J.S., E-mail: jsebas@us.es [Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de Materiales, CSIC Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain); Borrego, J.M.; Conde, C.F.; Conde, A. [Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de Materiales, CSIC Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain); Lozano-Perez, S. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Non-isothermal kinetics is easily analyzed using the present approach. Black-Right-Pointing-Pointer Local Avrami exponents are obtained for nanocrystallization in a wide range. Black-Right-Pointing-Pointer Results on nanocrystallization are explained in the frame of limited growth approach. Black-Right-Pointing-Pointer Deviations from isokinetic behavior is analyzed for two different multiple processes. - Abstract: The non-isothermal kinetics of primary crystallization processes is studied from numerically generated curves and their predictions have been tested in several nanocrystallization processes. Single processes and transformations involving two overlapped processes in a non-isothermal regime have been generated and deviations from isokinetic behavior are found when the overlapped processes have different activation energies. In the case of overlapped processes competing for the same type of atoms, the heating rate dependence of the obtained Avrami exponent can supply information on the activation energies of each individual processes. The application to experimental data of nanocrystallization processes is consistent with a limited growth approximation. In the case of preexisting crystallites in the as-cast samples, predictions on the heating rate dependence of the obtained Avrami exponents of multiple processes have been confirmed.

  11. Multiscale modelling and simulation of single crystal superalloy turbine blade casting during directional solidiifcation process

    Institute of Scientific and Technical Information of China (English)

    Xu Qingyan; Zhang Hang; Liu Baicheng

    2014-01-01

    As the key parts of an aero-engine, single crystal (SX) superalloy turbine blades have been the focus of much attention. However, casting defects often occur during the manufacturing process of the SX turbine blades. Modeling and simulation technology can help to optimize the manufacturing process of SX blades. Multiscale coupled models were proposed and used to simulate the physical phenomena occurring during the directional solidification (DS) process. Coupled with heat transfer (macroscale) and grain growth (meso-scale), 3D dendritic grain growth was calculated to show the competitive grain growth at micro-scale. SX grain selection behavior was studied by the simulation and experiments. The results show that the geometrical structure and technical parameters had strong inlfuences on the grain selection effectiveness. Based on the coupled models, heat transfer, grain growth and microstructure evolution of a complex holow SX blade were simulated. Both the simulated and experimental results show that the stray grain occurred at the platform of the SX blade when a constant withdrawal rate was used in manufacturing process. In order to avoid the formation of the stray crystal, the multi-scale coupled models and the withdrawal rate optimized technique were applied to the same SX turbine blade. The modeling results indicated that the optimized variable withdrawal rate can achieve SX blade castings with no stray grains, which was also proved by the experiments.

  12. Multiscale modelling and simulation of single crystal superalloy turbine blade casting during directional solidification process

    Directory of Open Access Journals (Sweden)

    Xu Qingyan

    2014-07-01

    Full Text Available As the key parts of an aero-engine, single crystal (SX superalloy turbine blades have been the focus of much attention. However, casting defects often occur during the manufacturing process of the SX turbine blades. Modeling and simulation technology can help to optimize the manufacturing process of SX blades. Multiscale coupled models were proposed and used to simulate the physical phenomena occurring during the directional solidification (DS process. Coupled with heat transfer (macroscale and grain growth (meso-scale, 3D dendritic grain growth was calculated to show the competitive grain growth at micro-scale. SX grain selection behavior was studied by the simulation and experiments. The results show that the geometrical structure and technical parameters had strong influences on the grain selection effectiveness. Based on the coupled models, heat transfer, grain growth and microstructure evolution of a complex hollow SX blade were simulated. Both the simulated and experimental results show that the stray grain occurred at the platform of the SX blade when a constant withdrawal rate was used in manufacturing process. In order to avoid the formation of the stray crystal, the multi-scale coupled models and the withdrawal rate optimized technique were applied to the same SX turbine blade. The modeling results indicated that the optimized variable withdrawal rate can achieve SX blade castings with no stray grains, which was also proved by the experiments.

  13. Numerical investigation of the influence of cooling flux on the generation of dislocations in cylindrical mono-like silicon growth

    Science.gov (United States)

    Gao, B.; Kakimoto, K.

    2013-12-01

    To effectively reduce dislocations during seeded growth of cylindrical monocrystalline-like silicon by controlling the cooling flux, the relationship between the generation of dislocations and cooling flux has been numerically studied. The results show that the generation of dislocations is determined by the cooling flux difference, not by the cooling flux inside the crystal. Good control of the input and output cooling fluxes during practical crystal growth is essential to reduce the generation of dislocations. Further analysis shows that the cooling flux difference in the radial or axial direction is linearly related to the square root of the maximum dislocation density. In other words, a linear decrease of the cooling flux difference in the radial or axial direction results in a quadratic decrease of the maximum dislocation density. Therefore, the most effective method to reduce dislocations during the cooling process is to decrease the cooling flux difference between the input and output fluxes, i.e., to decrease the energy accumulation or dissipation rate inside the whole crystal.

  14. Multi-response optimization of process parameters using Taguchi method and grey relational analysis during turning AA 7075/SiC composite in dry and spray cooling environments

    Directory of Open Access Journals (Sweden)

    P. C. Mishra

    2015-09-01

    Full Text Available Turning experiments were carried out on AA 7075/SiC composite workpiece in dry and spray cooling environments based on L16 Taguchi design of experiments. Multiple performance optimization of process parameters was performed using grey relational analysis. The performance characteristics considered were average surface roughness, cutting tool temperature and material removal rate. Uncoated carbide inserts were used for machining the workpiece in a high speed precision lathe. A grey relational grade obtained from grey relational analysis was used to optimize the process parameters. Optimal combination of process parameters was then determined by the Taguchi method using the grey relational grade as the performance index. Experimental results indicated that the turning in spray cooling environment was beneficial compared to that in dry environment for the quality response characteristics under consideration. Analysis of variance showed that feed was the most significant parameter for the multiple performance characteristics during turning in both the environments.

  15. Danish Cool

    DEFF Research Database (Denmark)

    Toft, Anne Elisabeth

    2016-01-01

    Danish Cool. Keld Helmer-Petersen, Photography and the Photobook Handout exhibition text in English and Chinese by Anne Elisabeth Toft, Curator The exhibition Danish Cool. Keld Helmer-Petersen, Photography and the Photobook presents the ground-breaking work of late Danish photographer Keld Helmer...

  16. Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns.

    Science.gov (United States)

    Kim, Jae-Hong; Oh, Seunghan; Uhm, Soo-Hyuk

    2016-01-01

    The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice-before and after crystallization-using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α = 0.05). Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P crystallization exceeded 120 μm, which is the clinically acceptable threshold.

  17. A comparison study on the melt crystallization kinetics of long chain branched and linear isotactic polypropylenes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The isothermal and non-isothermal crystallization kinetics of LCBPP and linear-iPP was investigated by optical microscopy and differential scanning calorimetry (DSC). The optical microscopy results in the isothermal crystallization process show that the crystals of LCBPP grow slower than the crystals of the linear-iPP. This originates from the low chain mobility, or in other words, the lower chain diffusion rate of LCBPP due to the existence of long side chains. The DSC results in the isothermal crystallization process show that the LCBPP exhibits, however, a higher overall crystallization rate with respect to the linear-iPP. This is related to the higher nucleation ability of LCBPP since the isothermal crystallization process of both LCBPP and linear-iPP are nucleation-dominated. Avrami analysis indicates that the nucleation nature and crystal growth manner of LCBPP and linear-iPP are about the same. The analyses of the non-isothermal crystallization processes indicate an increment in crystallization rate with increasing cooling rate. But at any cooling rate, the linear-iPP crystallizes more quickly than the LCBPP.This implies that the non-isothermal crystallization processes of LCBPP and linear-iPP are diffusion-dominated, in which the lower chain diffusion rate of LCBPP results in the slower crystallization of it.

  18. Crystallization Behavior of Solution-Processed CIGSe Thin Film Semiconductor by Stepwise Annealing Process.

    Science.gov (United States)

    Park, Mi Sun; Sung, Shi-Joon; Kim, Dae-Hwan

    2015-03-01

    CuIn(x)Ga1-xSe2 (CIGS) thin films were prepared by a solution-based CuInGa (CIG) precursor- selenization process. First, we investigated the effect of selenization temperature on the formation of polycrystalline CIGS and grain growth. The CIG precursor films were selenized using a two-step process to investigate the reaction of Se and CIG precursors during the formation of CIGS thin films. Depending on the temperature in the 1st step of the selenization process, the CIG precursor forms a different intermediate phase between the single phase to ternary phase such as Cu, Se, CuSe, InSe, and CuInSe2. In addition, the intermediate phase exerts a significant influence on the final phase obtained after the 2nd step of the selenization process, particularly with regard to characteristics such as polycrystalline structure and grain growth in the CIGS films. The photoelectron conversion efficiency of devices prepared using CIGS thin films was approximately 1.59-2.75%.

  19. Thermo-tunable hybrid photonic crystal fiber based on solution-processed chalcogenide glass nanolayers

    DEFF Research Database (Denmark)

    Markos, Christos

    2016-01-01

    The possibility to combine silica photonic crystal fiber (PCF) as low-loss platform with advanced functional materials, offers an enormous range of choices for the development of fiber-based tunable devices. Here, we report a tunable hybrid silica PCF with integrated As2S3 glass nanolayers inside...... antiresonances by taking advantage the high thermo-optic coefficient of the solution-processed nanolayers. Two different hybrid fiber structures, with core diameter 10 and 5 mu m, were developed and characterized using a supercontinuum source. The maximum sensitivity was measured to be as high as 3.6 nm...

  20. Effect of Continuous Casting Process Parameters on Equiaxial Crystal Ratio of 430 Ferritic Stainless Steel%连铸工艺参数对430铁素体不锈钢等轴晶率的影响

    Institute of Scientific and Technical Information of China (English)

    冯兵; 陈兴润; 王建泽

    2013-01-01

    在工业试验条件下分析了电磁搅拌电流强度、中包过热度和二冷水强度对430不锈钢连铸坯等轴晶率的影响规律.结果表明:430不锈钢连铸坯低倍组织由柱状晶和等轴晶组成;等轴晶率随电流强度的增大而依次增大,随过热度的减小而依次增大;采用较小的二冷水强度,430不锈钢低倍组织中的等轴晶率高.在电流强度为1 700A、中包过热度为20℃、二冷水比水量为0.95 L/kg时,430连铸坯生产的制品表面无起皱现象发生.%The effects of stirring current intensity,superheat in tundish and second cooling intensity on equiaxial crystal ratio of 430 stainless steel slab were analyzed under the conditions of industry test.The results show that macrostructure of 430 ferritic stainless steel slab consisted of columnar grains and equiaxial crystal grains.With the stirring current intensity increasing or superheat in tundish decreasing,the equiaxial crystal ratio of 430 stainless steel slab increases significantly.Weak cooling process is advantageous to obtaining high equiaxial crystal ratio.With current intensity of 1 700 A,superheat in tundish of 20 ℃ and second cooling intensity of 0.95 L/kg,the surface wrinkling of 430 cold-rolled plates do not happen.

  1. 间歇结晶过程的分批优化%Batch-to-batch Optimization of Batch Crystallization Processes

    Institute of Scientific and Technical Information of China (English)

    Woranee Paengjuntuek; Paisan Kittisupakorn; Amornchai Arpornwichanop

    2008-01-01

    It is the fact that several process parameters are either unknown or uncertain. Therefore, an optimal control profile calculated with developed process models with respect to such process parameters may not give an optimal performance when implemented to real processes. This study proposes a batch-to-batch optimization strat-egy for the estimation of uncertain kinetic parameters in a batch crystallization process of potassium sulfate produc-tion. The knowledge of a crystal size distribution of the product at the end of batch operation is used in the proposedmethodology. The updated kinetic parameters are applied for determining an optimal operating temperature policy for the next batch run.

  2. Coherent electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  3. The Crystal Structure of the Escherichia coli Autoinducer-2 Processing Protein LsrF

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Z.; Xavier, K; Miller, S

    2009-01-01

    Many bacteria produce and respond to the quorum sensing signal autoinducer-2 (AI-2). Escherichia coli and Salmonella typhimurium are among the species with the lsr operon, an operon containing AI-2 transport and processing genes that are up regulated in response to AI-2. One of the Lsr proteins, LsrF, has been implicated in processing the phosphorylated form of AI-2. Here, we present the structure of LsrF, unliganded and in complex with two phospho-AI-2 analogues, ribose-5-phosphate and ribulose-5-phosphate. The crystal structure shows that LsrF is a decamer of (??)8-barrels that exhibit a previously unseen N-terminal domain swap and have high structural homology with aldolases that process phosphorylated sugars. Ligand binding sites and key catalytic residues are structurally conserved, strongly implicating LsrF as a class I aldolase.

  4. The early crystal nucleation process in hard spheres shows synchronised ordering and densification

    Science.gov (United States)

    Berryman, Joshua T.; Anwar, Muhammad; Dorosz, Sven; Schilling, Tanja

    2016-12-01

    We investigate the early part of the crystal nucleation process in the hard sphere fluid using data produced by computer simulation. We find that hexagonal order manifests continuously in the overcompressed liquid, beginning approximately one diffusion time before the appearance of the first "solid-like" particle of the nucleating cluster, and that a collective influx of particles towards the nucleation site occurs simultaneously to the ordering process: the density increases leading to nucleation are generated by the same individual particle displacements as the increases in order. We rule out the presence of qualitative differences in the early nucleation process between medium and low overcompressions and also provide evidence against any separation of translational and orientational order on the relevant lengthscales.

  5. Utilization of process energy from supermarket refrigeration systems. Coupling of cooling and heating; Prozessenergienutzung von Supermarktkaelteanlagen. Kaelte-Waerme-Kopplung

    Energy Technology Data Exchange (ETDEWEB)

    Wirsching, Alexander [TEKO Gesellschaft fuer Kaeltetechnik mbH, Altenstadt (Germany). Technologie und Kommunikation

    2010-03-15

    The efficiency is defined as the relation between utility and expenditure. Thus, it is obvious for the specialist of refrigeration to tackle with the expenditure (energy consumption) since the utilization conventionally is defined as the produced/need cooling performance of a refrigeration plant. If refrigeration plants are regarded according to their function (withdrawal of heat from a refrigeration chamber and delivery to the environment), the heating system is the producer of the requirement for cooling in 'the winter' (heating season). Thus, the refrigeration plant perhaps already has a marvellous efficiency, and the separate heating system too - however in interaction. The broad view moves into the focus. The possible approaches and effects are described in the contribution under consideration using the example of a Discount supermarket with a sales area of 800 square meters and a requirement of cooling of more than 30 kW.

  6. Preparation of conduction-cooled HTS coils using Y-123 coated conductors by IBAD/PLD process

    Energy Technology Data Exchange (ETDEWEB)

    Fuji, H. [Fujikura Ltd., Material Technology Laboratory, Koto-ku, 1-5-1, Kiba, Tokyo 135-8512 (Japan)], E-mail: hfuji@fujikura.co.jp; Hanyu, S.; Kakimoto, K.; Iijima, Y.; Saitoh, T. [Fujikura Ltd., Material Technology Laboratory, Koto-ku, 1-5-1, Kiba, Tokyo 135-8512 (Japan)

    2007-10-01

    We have developed a long Y-123 coated conductors by ion-beam-assisted deposition (IBAD) and pulsed-laser-deposition (PLD) method. Now, we can routinely obtained 100 m class Y-123 tapes with over 100 A at 77 K. For power applications using Y-123 conductors, coiling and cooling techniques are important elements. From 2004, we have developed and demonstrated a solenoid type coil that is the most suitable for practical application because it has advantage such as (1) uniformity of magnetic field (2) no joint. In this paper, we describe the development of conduction-cooled HTS test coil that has 14 turn x 22 layers using 100 m Y-123 conductors. In order to use the conduction cooling system, the Y-123 conductors were stabilized for 0.1 mm thick Cu tapes and spacers between the layers consisted of aluminum nitride in the coils. In the demonstration of this coil at 30 K, 40 K, 50 K, 60 K and 77 K by cryo-cooling system, the good cooling and superconducting performances were observed. The central magnetic fields of over 1 T were successfully obtained with operating currents of over 400 A and under 40 K. Furthermore, this coil was operated on additional magnetic fields of 3 T by combination of LTS magnets. The central magnetic fields of 0.5 T were generated from the cooled HTS coils with operating current of 190 A on additional magnetic fields of 3 T by LTS magnets at 30 K. Total magnetic fields were exceeded 3.5 T at 30 K.

  7. Numerical Simulation of Plasma-Dynamical Processes in the Technological Inductively Coupled RF Plasmatron with Gas Cooling

    Directory of Open Access Journals (Sweden)

    Yu. M. Grishin

    2016-01-01

    Full Text Available The electrodeless inductively coupled RF plasmatron (ICP torches became widely used in various fields of engineering, science and technology. Presently, owing to development of new technologies to produce very pure substances, nanopowders, etc., there is a steadily increasing interest in the induction plasma. This generates a need for a broad range of theoretical and experimental studies to optimize the design and technological parameters of different ICP equipment.The paper presents a numerical model to calculate parameters of inductively coupled RF plasmatron with gas-cooling flow. A finite volume method is used for a numerical solution of a system of Maxwell's and heat transfer equations in the application package ANSYS CFX (14.5. The pseudo-steady approach to solving problems is used.A numerical simulation has been computed in the application package ANSYS CFX (14.5 for a specific design option of the technological ICP, which has a three-coils inductor and current amplitude in the range J к = 50-170 A (3 MHz. The pure argon flows in the ICP. The paper discusses how the value of discharge current impacts on the thermodynamic parameters (pressure, temperature and the power energy in discharge zone. It shows that the ICP can generate a plasma stream with a maximum temperature of about 10 kK and an output speed of 10-15 m/s. The work determines a length of the plasma stream with a weight average temperature of more than 4 kK. It has been found that in order to keep the quartz walls in normal thermal state, the discharge current amplitude should not exceed 150 A. The paper shows the features of the velocity field distribution in the channel of the plasma torch, namely, the formation of vortex in the position of the first coil. The results obtained are important for calculating the dynamics of heating and evaporation of quartz particles in the manufacturing processes for plasma processing of quartz concentrate into high-purity quartz and

  8. Capillary stability of vapor-liquid-solid crystallization processes and their comparison to Czochralski and Stepanov growth methods

    Science.gov (United States)

    Nebol'sin, Valery A.; Suyatin, Dmitry B.; Dunaev, Alexander I.; Tatarenkov, Alexander F.

    2017-04-01

    Epitaxial semiconductor nanowires grown with vapor-liquid-solid crystallization processes are very attractive nanoscale objects for many different applications. Despite extensive studies of the growth mechanism, there is still a lack of understanding of the growth process; in particular, the stability of the vapor-liquid-solid crystallization process has not previously been studied. Here we examine the capillary stability of the vapor-liquid-solid growth of nanowires and filamentary crystals with different diameters and demonstrate that the growth is stable for small Bond numbers when the meniscus height is linearly dependent on catalyst diameter. The capillary stability of vapor-liquid-solid growth is also compared with capillary stability in the Stepanov and Czochralski crystal growth methods; it is shown that capillary stability is not possible in the Czochralski method, although it is possible in the Stepanov growth method when the ratio of crystal diameter to shaper diameter is >1/2. These findings are important for better understanding and improved control of the growth of nanowires and filamentary crystals and indicate, for example, that large diameter filamentary crystals can be grown via a vapor-liquid-solid mechanism if the influence of gravity forces on the liquid catalytic particle shape can be reduced.

  9. Numerical simulation on vacuum solution heat treatment and gas quenching process of a low rhenium-containing Ni-based single crystal turbine blade

    Directory of Open Access Journals (Sweden)

    Zhe-xin Xu

    2016-11-01

    Full Text Available Numerical heat-transfer and turbulent flow model for an industrial high-pressure gas quenching vacuum furnace was established to simulate the heating, holding and gas fan quenching of a low rhenium-bearing Ni-based single crystal turbine blade. The mesh of simplified furnace model was built using finite volume method and the boundary conditions were set up according to the practical process. Simulation results show that the turbine blade geometry and the mutual shielding among blades have significant influence on the uniformity of the temperature distribution. The temperature distribution at sharp corner, thin wall and corner part is higher than that at thick wall part of blade during heating, and the isotherms show a toroidal line to the center of thick wall. The temperature of sheltered units is lower than that of the remaining part of blade. When there is no shelteration among multiple blades, the temperature distribution for all blades is almost identical. The fluid velocity field, temperature field and cooling curves of the single and multiple turbine blades during gas fan quenching were also simulated. Modeling results indicate that the loading tray, free outlet and the location of turbine blades have important influences on the flow field. The high-speed gas flows out from the nozzle is divided by loading tray, and the free outlet enhanced the two vortex flow at the end of the furnace door. The closer the blade is to the exhaust outlet and the nozzle, the greater the flow velocity is and the more adequate the flow is. The blade geometry has an effect on the cooling for single blade and multiple blades during gas fan quenching, and the effects in double layers differs from that in single layer. For single blade, the cooing rate at thin-walled part is lower than that at thick-walled part, the cooling rate at sharp corner is greater than that at tenon and blade platform, and the temperature at regions close to the internal position is

  10. Atomic simulation of amorphization and crystallization of Ag50 Au50 alloy during rapid solidification

    Institute of Scientific and Technical Information of China (English)

    王丽; 杨华; 张均艳; 边秀房; 衣粟

    2002-01-01

    By means of constant temperature and constant pressure molecular dynamic simulation technique, a series of simulations of the glass transition and crystallization processes of Ag50Au50 were performed. The atoms interact via EAM potential function. Pair correlation functions of liquid Ag50Au50 during different cooling rates and temperatures were simulated to reveal the structural features of liquid, super-cooled liquid, glass state and crystal. The thermodynamics and kinetics of structure transition of Ag50Au50 during cooling processes were performed.

  11. The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Mansur, E-mail: ma960@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Savvakin, Dmytro G.; Ivasishin, Orest M. [Institute for Metal Physics, National Academy of Sciences of Ukraine, UA-03142 Kiev (Ukraine); Pereloma, Elena V. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Electron Microscopy Centre, University of Wollongong, NSW 2519 (Australia)

    2013-08-01

    Two near-β titanium alloys, Ti–5Al–5Mo–5V–1Cr–1Fe and a modified one containing 2 wt% Cr (Ti–5Al–5Mo–5V–2Cr–1Fe) were produced from Ti hydride precursor powders via the cost-effective blended elemental powder metallurgy technique. The effects of two cooling rates (10 K s{sup −1} and 1 K s{sup −1}) during thermo-mechanical processing on the microstructure and mechanical properties were investigated using X-ray diffraction and scanning electron microscopy. X-ray line profile analysis revealed that dislocation densities and microstrain in β-Ti phase are higher than in α-Ti phase for all cases. In both alloys, slower cooling results in an increase in α volume fraction and promotes morphology of continuous grain boundary α phase. A lower total elongation is obtained in both alloys under slower cooling which could be accounted for by the continuous morphology of α phase. Overall, Ti–5Al–5Mo–5V–1Cr–1Fe displays higher ultimate tensile strength and total elongation compared to Ti–5Al–5Mo–5V–2Cr–1Fe, regardless of the cooling rate.

  12. Review of state-of-the-art of solar collector corrosion processes. Task 1 of solar collector studies for solar heating and cooling applications. Final technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, J E; Diegle, R B

    1980-04-11

    The state-of-the-art of solar collector corrosion processes is reviewed, and Task 1 of a current research program on use of aqueous heat transfer fluids for solar heating and cooling is summarized. The review of available published literature has indicated that lack of quantitative information exists relative to collector corrosion at the present time, particularly for the higher temperature applications of solar heating and cooling compared to domestic water heating. Solar collector systems are reviewed from the corrosion/service life viewpoint, with emphasis on various applications, collector design, heat transfer fluids, and freeze protection methods. Available information (mostly qualitative) on collector corrosion technology is reviewed to indicate potential corrosion problem areas and corrosion prevention practices. Sources of limited quantitative data that are reviewed are current solar applications, research programs on collector corrosion, and pertinent experience in related applications of automotive cooling and non-solar heating and cooling. A data bank was developed to catalog corrosion information. Appendix A of this report is a bibliography of the data bank, with abstracts reproduced from presently available literature accessions (about 220). This report is presented as a descriptive summary of information that is contained in the data bank.

  13. Empirical Modeling of Heating Element Power for the Czochralski Crystallization Process

    Directory of Open Access Journals (Sweden)

    Magnus Komperød

    2010-01-01

    Full Text Available The Czochralski (CZ crystallization process is used to produce monocrystalline silicon. Monocrystalline silicon is used in solar cell wafers and in computers and electronics. The CZ process is a batch process, where multicrystalline silicon is melted in a crucible and later solidifies on a monocrystalline seed crystal. The crucible is heated using a heating element where the power is manipulated using a triode for alternating current (TRIAC. As the electric resistance of the heating element increases by increased temperature, there are significant dynamics from the TRIAC input signal (control system output to the actual (measured heating element power. The present paper focuses on empirical modeling of these dynamics. The modeling is based on a dataset logged from a real-life CZ process. Initially the dataset is preprocessed by detrending and handling outliers. Next, linear ARX, ARMAX, and output error (OE models are identfied. As the linear models do not fully explain the process' behavior, nonlinear system identification is applied. The Hammerstein-Wiener (HW model structure is chosen. The final model identified is a Hammerstein model, i.e. a HW model with nonlinearity at the input, but not at the output. This model has only one more identified parameter than the linear OE model, but still improves the optimization criterion (mean squared ballistic simulation errors by a factor of six. As there is no nonlinearity at the output, the dynamics from the prediction error to the model output are linear, which allows a noise model to be added. Comparison of a Hammerstein model with noise model and the linear ARMAX model, both optimized for mean squared one-step-ahead prediction errors, shows that this optimization criterion is 42% lower for the Hammerstein model. Minimizing the number of parameters to be identified has been an important consideration throughout the modeling work.

  14. Switching processes in TGS crystals irradiated by high-current electron beam

    CERN Document Server

    Efimov, V V; Klevtsova, E A; Tyutyunnikov, S I

    2002-01-01

    The relaxation processes study of the dielectric permittivity epsilon during commutation of the external electric field in triglycine sulphate (NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4 (TGS) single crystal plates before and after irradiation by a high-current pulsed electron beam with different doses at various temperatures is presented. The parameters of the electron beam produced by the accelerator facility as a source were: energy E = 250 keV, current density I = 1000 A/cm sup 2 , fluence F = 15 J/cm sup 2 , pulse duration tau = 300 ns, beam density 5 centre dot sup 1 5 electrons/cm sup 2 per pulse. It was shown that the dependences of epsilon (t) are described by the Kohlrausch law: epsilon (t) approx exp (-t/tau) supalpha, where alpha is the average relaxation time of the all volume samples, 0 < alpha <1. Besides, it was found that switching processes in the irradiated crystals were much more intensive than those in the non-irradiated ones. The relaxation times decrease with rising...

  15. Numerical investigation of carbon contamination during the melting process of Czochralski silicon crystal growth

    Science.gov (United States)

    Liu, Xin; Gao, Bing; Kakimoto, Koichi

    2015-05-01

    Czochralski (CZ) growth of single silicon (Si) crystals is invariably accompanied by transport of impurities such as carbon (C), oxygen (O), and related compounds produced by reactions at high temperature. To study the generation and accumulation of C during the melting process, a transient global model was developed that included coupled O and C transport. Transport phenomena of C, O, and related compounds were predicted by considering five chemical reactions in the furnace. The dynamic behavior of impurities was revealed during the melting process of the Si feedstock. It was found that C contamination is activated once the melting front contacts argon gas. For accurate control of C contamination in CZ-Si crystals, the accumulation of C during the melting stage should be considered. Parameter studies of furnace pressure and gas flow rate were conducted on the accumulation of C during the melting stage. At the gas/melt interface, pressure and flow rate affected the C flux in different ways. The results suggest that increase in gas flow rate could reduce C contamination much more effectively than decrease in pressure.

  16. Evaluating the impact of an ammonia-based post-combustion CO2 capture process on a steam power plant with different cooling water temperatures

    DEFF Research Database (Denmark)

    Linnenberg, Sebastian; Darde, Victor Camille Alfred; Oexmann, Jochen

    2012-01-01

    The use of aqueous ammonia is a promising option to capture carbon dioxide from the flue gas of coal-fired power plants. Compared to a capture process using monoethanolamine (MEA), the use of ammonia can reduce the heat requirement of the CO2 desorption significantly, although an additional effort...... is necessary to provide the cooling of the process. To allow for a fair evaluation of the integration of this CO2 capture process into a power plant process, an overall process evaluation is carried out. The use of detailed models of the power plant, of the compressor and of the CO2 capture process enables....... Additionally, two different process configurations of the capture plant, with either one single absorber or two absorbers connected in series where the first absorber captures the majority of the CO2 and the second limits the NH3 slip, are evaluated.The influence of the main process parameters (desorber...

  17. Summer cooling in the east central Arabian Sea - a process of dynamic response to the southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Sastry, J.S.

    The cooling of the east central Arabian Sea during summer monsoon season is examined using data sets of MONEX '79 and MONSOON '77 programmes. These studies have revealed that downward transfer of heat due to the mixing of warm surface and cold sub...

  18. Cryopreservation: Vitrification and Controlled Rate Cooling.

    Science.gov (United States)

    Hunt, Charles J

    2017-01-01

    Cryopreservation is the application of low temperatures to preserve the structural and functional integrity of cells and tissues. Conventional cooling protocols allow ice to form and solute concentrations to rise during the cryopreservation process. The damage caused by the rise in solute concentration can be mitigated by the use of compounds known as cryoprotectants. Such compounds protect cells from the consequences of slow cooling injury, allowing them to be cooled at cooling rates which avoid the lethal effects of intracellular ice. An alternative to conventional cooling is vitrification. Vitrification methods incorporate cryoprotectants at sufficiently high concentrations to prevent ice crystallization so that the system forms an amorphous glass thus avoiding the damaging effects caused by conventional slow cooling. However, vitrification too can impose damaging consequences on cells as the cryoprotectant concentrations required to vitrify cells at lower cooling rates are potentially, and often, harmful. While these concentrations can be lowered to nontoxic levels, if the cells are ultra-rapidly cooled, the resulting metastable system can lead to damage through devitrification and growth of ice during subsequent storage and rewarming if not appropriately handled.The commercial and clinical application of stem cells requires robust and reproducible cryopreservation protocols and appropriate long-term, low-temperature storage conditions to provide reliable master and working cell banks. Though current Good Manufacturing Practice (cGMP) compliant methods for the derivation and banking of clinical grade pluripotent stem cells exist and stem cell lines suitable for clinical applications are available, current cryopreservation protocols, whether for vitrification or conventional slow freezing, remain suboptimal. Apart from the resultant loss of valuable product that suboptimal cryopreservation engenders, there is a danger that such processes will impose a selective

  19. Non-isothermal Crystallization Kinetics of Modified Poly (ethylene terephthalate) with Ultraviolet Protection

    Institute of Scientific and Technical Information of China (English)

    TENG Cui-qing

    2002-01-01

    The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer under non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system.

  20. Laser cooling of a semiconductor by 40 kelvin.

    Science.gov (United States)

    Zhang, Jun; Li, Dehui; Chen, Renjie; Xiong, Qihua

    2013-01-24

    Optical irradiation accompanied by spontaneous anti-Stokes emission can lead to cooling of matter, in a phenomenon known as laser cooling, or optical refrigeration, which was proposed by Pringsheim in 1929. In gaseous matter, an extremely low temperature can be obtained in diluted atomic gases by Doppler cooling, and laser cooling of ultradense gas has been demonstrated by collisional redistribution of radiation. In solid-state materials, laser cooling is achieved by the annihilation of phonons, which are quanta of lattice vibrations, during anti-Stokes luminescence. Since the first experimental demonstration in glasses doped with rare-earth metals, considerable progress has been made, particularly in ytterbium-doped glasses or crystals: recently a record was set of cooling to about 110 kelvin from the ambient temperature, surpassing the thermoelectric Peltier cooler. It would be interesting to realize laser cooling in semiconductors, in which excitonic resonances dominate, rather than in systems doped with rare-earth metals, where atomic resonances dominate. However, so far no net cooling in semiconductors has been achieved despite much experimental and theoretical work, mainly on group-III-V gallium arsenide quantum wells. Here we report a net cooling by about 40 kelvin in a semiconductor using group-II-VI cadmium sulphide nanoribbons, or nanobelts, starting from 290 kelvin. We use a pump laser with a wavelength of 514 nanometres, and obtain an estimated cooling efficiency of about 1.3 per cent and an estimated cooling power of 180 microwatts. At 100 kelvin, 532-nm pumping leads to a net cooling of about 15 kelvin with a cooling efficiency of about 2.0 per cent. We attribute the net laser cooling in cadmium sulphide nanobelts to strong coupling between excitons and longitudinal optical phonons (LOPs), which allows the resonant annihilation of multiple LOPs in luminescence up-conversion processes, high external quantum efficiency and negligible background

  1. Beta tricalcium phosphate ceramics with controlled crystal orientation fabricated by application of external magnetic field during the slip casting process.

    Science.gov (United States)

    Hagio, Takeshi; Yamauchi, Kazushige; Kohama, Takenori; Matsuzaki, Toshiya; Iwai, Kazuhiko

    2013-07-01

    Beta tricalcium phosphate (β-TCP) is a resorbable bioceramic that has hitherto been utilized in the medical field. Since it crystallizes in the anisotropic hexagonal system, properties such as chemical and physical ones are expected to depend on its crystal axis direction and/or on its crystal plane (anisotropy). Control of crystal orientation is thus important when used in polycrystalline form. Meanwhile, application of a strong magnetic field has been found to be a promising technique to control crystal orientation of anisotropic shape or structured crystals. In this work, we attempted to fabricate β-TCP ceramics with controlled crystal orientation by applying an external magnetic field during the slip casting process and subsequently sintering them at 1050°C, below the β-α transition temperature. Application of a vertical magnetic field increased intensities of planes perpendicular to c-plane on the top surface, while a horizontal one with simultaneous mechanical mold rotation decreased it. These results indicated that crystal orientation of β-TCP ceramics were successfully controlled by the external magnetic field and together that the magnetic susceptibility of β-TCP is χ(c[perpendicular])>χ(c//).

  2. Multi-response optimization of process parameters using Taguchi method and grey relational analysis during turning AA 7075/SiC composite in dry and spray cooling environments

    OpenAIRE

    Mishra, P. C.; D. K. Das; M. Ukamanal; B. C. Routara; Sahoo, A.K.

    2015-01-01

    Turning experiments were carried out on AA 7075/SiC composite workpiece in dry and spray cooling environments based on L16 Taguchi design of experiments. Multiple performance optimization of process parameters was performed using grey relational analysis. The performance characteristics considered were average surface roughness, cutting tool temperature and material removal rate. Uncoated carbide inserts were used for machining the workpiece in a high speed precision lathe. A grey relational ...

  3. Analysis of Surface Chemistry and Detector Performance of Chemically Process CdZnTe crystals

    Energy Technology Data Exchange (ETDEWEB)

    HOSSAIN, A.; Yang, G.; Sutton, J.; Zergaw, T.; Babalola, O. S.; Bolotnikov, A. E.; Camarda. ZG. S.; Gul, R.; Roy, U. N., and James, R. B.

    2015-10-05

    The goal is to produce non-conductive smooth surfaces for fabricating low-noise and high-efficiency CdZnTe devices for gamma spectroscopy. Sample preparation and results are discussed. The researachers demonstrated various bulk defects (e.g., dislocations and sub-grain boundaries) and surface defects, and examined their effects on the performance of detectors. A comparison study was made between two chemical etchants to produce non-conductive smooth surfaces. A mixture of bromine and hydrogen peroxide proved more effective than conventional bromine etchant. Both energy resolution and detection efficiency of CZT planar detectors were noticeably increased after processing the detector crystals using improved chemical etchant and processing methods.

  4. Spin reorientation transition process in single crystal NdFeO3

    Science.gov (United States)

    Song, Gaibei; Jiang, Junjie; Kang, Baojuan; Zhang, Jincang; Cheng, Zhenxiang; Ma, Guohong; Cao, Shixun

    2015-06-01

    The spin reorientation transition in single crystal NdFeO3 is studied using AC magnetic susceptibility, hysteresis loops, and polarized terahertz (THz) time domain spectroscopy measurements. Different frequency dependence behaviors of AC susceptibility reflect that the dynamic response of magnetization inside the spin reorientation region differs from the phase outside the transition region. The magnetization hysteresis loops at different temperatures reveal that domains formed during the spin reorientation process, which coincides with the abrupt increase of AC magnetic susceptibility during the transition. In addition, temperature dependent THz wave excitation of quasi-antiferromagnetic mode indicates the process of spin reorientation as a continuous rotation of Fe3+ spins rather than a mixed phase of Γ4 and Γ2.

  5. Study of polycrystalline silicon obtained by aluminum-induced crystallization depending on process conditions

    Science.gov (United States)

    Pereyaslavtsev, Alexander; Sokolov, Igor; Sinev, Leonid

    2016-11-01

    In this paper, we have decided to consider an alternative method of producing polycrystalline silicon and study change of its electrophysical characteristics depending on process parameters. As an alternative low-pressure chemical vapor deposition method appears aluminum-induced crystallization (AIC), which allows to obtain a polycrystalline silicon film is significantly larger grain size, thereby reducing contribution of grain boundaries. A comprehensive study of polycrystalline silicon was carried out using a variety of microscopic (OM, SEM) and spectroscopic (RAMAN, XPS) and diffraction (EBSD, XRD) analytic methods. We also considered possibility of self-doping in AIC, result of which was obtained polycrystalline silicon with different resistance. Additionally considered changes in temperature coefficient of resistance depending on technological parameters of AIC process.

  6. In situ diagnostics of the crystal-growth process through neutron imaging

    DEFF Research Database (Denmark)

    Tremsin, Anton S.; Makowska, Malgorzata Grazyna; Perrodin, Didier

    2016-01-01

    Neutrons are known to be unique probes in situations where other types of radiation fail to penetrate samples and their surrounding structures. In this paper it is demonstrated how thermal and cold neutron radiography can provide time-resolved imaging of materials while they are being processed (e......, as limited by the resolution of the present experiments). It is also demonstrated that the dopant concentration can be quantified even for very low concentration levels (∼ 0.1%) in 10 mm thick samples. The interface between the solid and liquid phases can also be imaged, provided there is a sufficient change.......g. while growing single crystals). The processing equipment, in this case furnaces, and the scintillator materials are opaque to conventional X-ray interrogation techniques. The distribution of the europium activator within a BaBrCl:Eu scintillator (0.1 and 0.5% nominal doping concentrations per mole...

  7. Numerical Simulation and Optimization of Directional Solidification Process of Single Crystal Superalloy Casting

    Directory of Open Access Journals (Sweden)

    Hang Zhang

    2014-02-01

    Full Text Available The rapid development of numerical modeling techniques has led to more accurate results in modeling metal solidification processes. In this study, the cellular automaton-finite difference (CA-FD method was used to simulate the directional solidification (DS process of single crystal (SX superalloy blade samples. Experiments were carried out to validate the simulation results. Meanwhile, an intelligent model based on fuzzy control theory was built to optimize the complicate DS process. Several key parameters, such as mushy zone width and temperature difference at the cast-mold interface, were recognized as the input variables. The input variables were functioned with the multivariable fuzzy rule to get the output adjustment of withdrawal rate (v (a key technological parameter. The multivariable fuzzy rule was built, based on the structure feature of casting, such as the relationship between section area, and the delay time of the temperature change response by changing v, and the professional experience of the operator as well. Then, the fuzzy controlling model coupled with CA-FD method could be used to optimize v in real-time during the manufacturing process. The optimized process was proven to be more flexible and adaptive for a steady and stray-grain free DS process.

  8. Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns

    Directory of Open Access Journals (Sweden)

    Jae-Hong Kim

    2016-01-01

    Full Text Available The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice—before and after crystallization—using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α=0.05. Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P<0.05. None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120 μm, which is the clinically acceptable threshold.

  9. Evaluation of Morphological Change and Aggregation Process of Ice Crystals in Frozen Food by Using Fractal Analysis

    Science.gov (United States)

    Koshiro, Yoko; Watanabe, Manabu; Takai, Rikuo; Hagiwara, Tomoaki; Suzuki, Toru

    Size and shape of ice crystals in frozen food materials are very important because they affect not only quality of foods but also the viability of industrial processing such as freeze-drying of concentration. In this study, 30%wt sucrose solution is used as test samples. For examining the effect of stabilizerspectine and xantan gum is added to the sucrose solution. They are frozen on the cold stage of microscope to be observed their growing ice crystals under the circumstance of -10°C. Their size and shape are measured and quantitatively evaluated by applying fractal analysis. lce crystal of complicated shape has large fractal dimension, and vice versa. It successflly categorized the ice crystals into two groups; one is a group of large size and complicated shape, and the other is a group of small size and plain shape. The critical crystal size between the two groups is found to become larger with increasing holding time. It suggests a phenomenological model for metamorphoses process of ice crystals. Further, it is indicated that xantan gum is able to suppress the smoothing of ice crystals.

  10. Study on separation of chlorobenzene and acetic acid azeotrope by distillation-crystallization hybrid separation process%蒸馏-结晶耦合工艺分离乙酸-氯苯共沸体系的研究

    Institute of Scientific and Technical Information of China (English)

    宋闯

    2015-01-01

    本文主要对蒸馏-结晶耦合工艺分离共沸体系进行研究。以乙酸-氯苯为研究对象,对耦合工艺的原理和实验装置进行研究设计。通过对回流比,结晶终温,降温速率和发汗等工艺条件的考察,得出蒸馏-结晶耦合工艺分离乙酸-氯苯共沸体系的最佳条件,即:最佳回流比为2,结晶终温为-6℃,降温速率为0.2618℃/min.,发汗时间为2.5h。%This paper mainly studies that binary azeotrope system has been separated by the distillation-crystallization hybrid separa-tion process .Taken chlorobenzene and acetic acid for researching objects,the principle of hybrid separation process was studied and the experimental equipment was designed.By studing of the reflux ratio, final crystallization temperatures,the cooling rate and sweating, opti-mum conditions of separating chlorobenzene-acetic acid azeotrope by distillation-crystallization hybrid separation process were determined. The best reflux ratio was 2, the final crystallization temperature was -6℃, the cooling rate was 0.2618℃/min, sweating time was 2.5h.

  11. Anomalous law of cooling

    OpenAIRE

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Oliveira, Fernando A.; Rubí, J. Miguel

    2014-01-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergo a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature ma...

  12. Cooling with Superfluid Helium

    CERN Document Server

    Lebrun, P

    2014-01-01

    The technical properties of helium II (‘superfluid’ helium) are presented in view of its applications to the cooling of superconducting devices, particularly in particle accelerators. Cooling schemes are discussed in terms of heat transfer performance and limitations. Large-capacity refrigeration techniques below 2 K are reviewed, with regard to thermodynamic cycles as well as process machinery. Examples drawn from existing or planned projects illustrate the presentation. Keywords: superfluid helium, cryogenics

  13. Modelling heating effects in cryocooled protein crystals

    CERN Document Server

    Nicholson, J; Fayz, K; Fell, B; Garman, E

    2001-01-01

    With the application of intense X-ray beams from third generation synchrotron sources, damage to cryocooled macromolecular crystals is being observed more commonly . In order to fully utilize synchrotron facilities now available for studying biological crystals, it is essential to understand the processes involved in radiation damage and beam heating so that, if possible, action can be taken to slow the rate of damage. Finite Element Analysis (FEA) has been applied to model the heating effects of X-rays on cryocooled protein crystals, and to compare the relative cooling efficiencies of nitrogen and helium.

  14. Multiscale Crystal Plasticity Modeling Considering Nucleation of Dislocations Based on Thermal Activation Process on Ultrafine-grained Aluminum

    Science.gov (United States)

    Aoyagi, Y.

    2017-05-01

    In this study, a crystal plasticity model expressing the behavior of the dislocation source and the mobile dislocations is proposed by considering a thermal activation process of dislocations. In order to predict the variation of critical resolved shear stress due to grain boundaries, mobile dislocations, or dislocation sources, information on these crystal defects is introduced into a hardening law of crystal plasticity. The crystal orientation and shape of ultrafine-grained (UFG) aluminum produced by accumulative roll bonding processes are measured by electron backscatter diffraction (EBSD). Mechanical properties of the UFG aluminum are estimated using tensile test and indentation test. Results obtained by EBSD are introduced into a computational model. Finite element simulation for polycrystal of aluminum investigates the effect of microstructure on mechanical properties of UFG aluminum.

  15. Glass transition and crystallization process of hard magnetic bulk Nd60Al10Fe20Co10 metallic glass

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Glass transition and crystallization process of bulk Nd60Al10Fe20Co10 metallic glass were investigated by means of dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electronic microscopy (SEM). It is shown that the glass transition and onset crystallization temperature determined by DMTA at a heating rate of 0.167 K/s are 480 and 588 K respectively. The crystallization process of the metallic glass is concluded as follows: amorphous α→α′+metastable FeNdAl novel phase →α′+primary δ phase→primary δ phase+eutectic δ phase Nd3Al phase+Nd3Co phase. The appearance of hard magnetism in this alloy is ascribed to the presence of amorphous phase with highly relaxed structure. The hard magnetism disappeared after the eutectic crystallization of amorphous phase.

  16. Evaluation of critical cooling rate of Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} metallic glass by containerless solidification process

    Energy Technology Data Exchange (ETDEWEB)

    Yodoshi, N., E-mail: ynoriharu@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamada, R. [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8578 (Japan); Kawasaki, A. [Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan); Makino, A. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2015-09-15

    Highlights: • Monodispersed Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} particles were successfully prepared by our containerless process. • The cooling rates of obtained particles were estimated by a model based on Newton’s law of cooling. • The critical cooling rate to form the fully amorphous phase was estimated in less than 550 K/s. • We revealed that the Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} alloy has sufficient inherent glass-forming ability. - Abstract: We aim to prepare monodispersed and homogenous spherical particles of pure Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} metallic glass with a low content of nucleation sites, and to evaluate the intrinsic glass-forming ability of Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} alloys by containerless solidification. Monodispersed Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} particles were successfully prepared by our originally developed pulsated orifice ejection method under He and Ar gas atmosphere. All obtained particles, with diameters ranging from 313 to 664 μm, were identified as single glassy or amorphous phases by X-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The critical cooling rate to form the fully glassy or amorphous phase was estimated in less than 550 K/s by a Newtonian cooling model. The results show that the Fe{sub 76}Si{sub 9}B{sub 10}P{sub 5} alloy has sufficient glass-forming ability under restrained nucleation conditions.

  17. Crystallization of Low-alloyed Construction Cast Steel Modified with V and Ti

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2013-07-01

    Full Text Available In this paper crystallization studies of low-alloyed construction cast steel were presented for different additions of chromium, nickel and molybdenum modified with vanadium and titanium. Studies were conducted using developed TDA stand, which additionally enabled evaluation of cooling rate influence on crystallization process of investigated alloys.

  18. Application-oriented Crystallization of Pharmaceutical Products

    DEFF Research Database (Denmark)

    Bruun Hansen, Thomas

    2017-01-01

    The purpose of this PhD thesis is to investigate various options for controlling the crystallization process of pharmaceutical products, both with regards to polymorphic control and crystal morphology. During this process, several model compounds were used, depending on the goal of the studies...... crystallizations were performed at fixed cooling rates, but also using Supersaturation control SSC and direct nucleation control DNC, to determine the temperature set point of the reactor. The impacts on crystal size, especially from the DNC experiments were quite impressive and clearly showed the advantages...... bonding behavior of the two compounds, but also to build the foundation for further studies using a compound that would allow for better monitoring using FT-IR. In this study the solubility of INA in several solvents have been determined, furthermore the crystallization of different polymorphs during...

  19. Study on the crystallization process of function inorganic crystal materials%无机功能晶体材料的结晶过程研究

    Institute of Scientific and Technical Information of China (English)

    孙丛婷; 薛冬峰

    2014-01-01

    Functional crystal materials used as the important conversion media of light,sound and electricity,have been widely applied to high-tech fields such as energy,information,aerospace and related hot topics at the forefront of materials science and engineering subject.Crystallization process is the core of the preparation of functional materials,crystal growth habit of materials directly affects the functional performances of optical,electrical,magnetic,and catalytic behaviors.During the crystallization process of inorganic materials,crystals are microscopically transformed from free-state ions into the crystalline solid-phase.We can use the ionic electronegativity and microscopic symmetry changes of constituent components,to study the crystallization process of aggregation formation and structure evolution.Using molecular vibration spectroscopy we can at the molecular scale,reveal the crystallization process of nonlinear optical crystal materials in aqueous solution crystallization process,to overcome the lack of traditional means of in situ observations determining those non-long-range order structures.Chemical bonding theory of single crystal growth can from both thermodynamic and kinetic aspects of the whole system,effectively guide the growth of large crystals,reasonably regulate the growth surface and interface thermodynamics and kinetics.The chemical bonding theory of single crystal growth is applied to the design and optimization of growth parameters of large-size crystal pulling growth system,we have built up a large-size crystal growth system,and successfully grown φ2" sapphire crystals,φ3" YAG crystals,and φ4" lithium niobate crystals.%功能晶体材料作为光、声、电等转换的重要介质,已经被广泛应用于能源、信息、航空航天等高新技术领域,是目前国际材料科学与工程学科发展的热点和前沿课题.结晶过程是制备功能材料的核心环节,结晶习性直接影响材料的光、电、磁、催化等

  20. Alternative technique for laser cooling with superradiance

    Science.gov (United States)

    Nemova, Galina; Kashyap, Raman

    2011-01-01

    We present a theoretical scheme for laser cooling of rare-earth-doped solids with optical superradiance (SR), which is the coherent, sharply directed spontaneous emission of photons by a system of laser-excited rare-earth ions in the solid-state host (glass or crystal). We consider an Yb+-doped ZnF4-BaF2-LaF3-AlF3-NaF (ZBLAN) sample pumped at a wavelength 1015 nm, with a rectangular pulsed source with a power of ˜433 W and a duration of 10 ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits an increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare-earth-doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy glasses for laser cooling.

  1. Dielectric relaxation process of a partially unwound helical structure in ferroelectric liquid crystals.

    Science.gov (United States)

    Choudhary, Amit; Bawa, Ambika; Rajesh; Singh, Surinder P; Biradar, Ashok M

    2017-06-01

    The fluctuations of unwound helical structure have been observed in deformed helix ferroelectric liquid crystal (DHFLC) and conventional FLC sample cells. The helix is partially unwound by strong anchoring on the substrates. In such sample cells, the helical decarlization lines are not observed in the texture under crossed polarized microscope. The dielectric spectroscopy is employed to observe the behavior of dielectric relaxation processes in these sample cells. A dielectric relaxation process is observed at a lower frequency than the Goldstone mode processes in DHFLC and FLC, which we call partially unwound helical mode (p-UHM). However, the p-UHM process is not observed in the sample cell in which the helical lines appear. The application of various amplitudes of probing ac voltages on this mode has shown the higher frequency shift, i.e., the larger the amplitude of ac voltage, the higher is the relaxation frequency of p-UHM. At sufficient amplitude of applied probing ac voltage, the p-UHM merges with the Goldstone mode process and is difficult to detect. However, the Goldstone mode relaxation frequency is almost independent of the cell geometry and sample configuration. The electro-optical behavior of the p-UHM has also been confirmed by electro-optical technique. The dielectric relaxation of UHM at a frequency lower than the Goldstone mode is interpreted as the fluctuation of partially unwound helix.

  2. Laser cooling of organic-inorganic lead halide perovskites

    Science.gov (United States)

    Ha, Son-Tung; Shen, Chao; Zhang, Jun; Xiong, Qihua

    2016-02-01

    Optical irradiation with suitable energy can cool solids, a phenomenon known as optical refrigeration, first proposed in 1929 and experimentally achieved in ytterbium-doped glasses in 1995. Since then, considerable progress has been made in various rare earth element-doped materials, with a recent record of cooling to 91 K directly from ambient temperatures. For practical use and to suit future applications of optical refrigeration, the discovery of materials with facile and scalable synthesis and high cooling power density will be required. Herein we present the realization of a net cooling of 23.0 K in micrometre-thick 3D CH3NH3PbI3 (MAPbI3) and 58.7 K in exfoliated 2D (C6H5C2H4NH3)2PbI4 (PhEPbI4) perovskite crystals directly from room temperature. We found that the perovskite crystals exhibit strong photoluminescence upconversion and near unity external quantum efficiency, properties that are responsible for the realization of net laser cooling. Our findings indicate that solution-processed perovskite thin films may be a highly suitable candidate for constructing integrated optical cooler devices.

  3. Influence of nanomechanical crystal properties on the comminution process of particulate solids in spiral jet mills.

    Science.gov (United States)

    Zügner, Sascha; Marquardt, Karin; Zimmermann, Ingfried

    2006-02-01

    Elastic-plastic properties of single crystals are supposed to influence the size reduction process of bulk materials during jet milling. According to Pahl [M.H. Pahl, Zerkleinerungstechnik 2. Auflage. Fachbuchverlag, Leipzig (1993)] and H. Rumpf: [Prinzipien der Prallzerkleinerung und ihre Anwendung bei der Strahlmahlung. Chem. Ing. Tech., 3(1960) 129-135.] fracture toughness, maximum strain or work of fracture for example are strongly dependent on mechanical parameters like hardness (H) and young's modulus of elasticity (E). In addition the dwell time of particles in a spiral jet mill proved to correlate with the hardness of the feed material [F. Rief: Ph. D. Thesis, University of Würzburg (2001)]. Therefore 'near-surface' properties have a direct influence on the effectiveness of the comminution process. The mean particle diameter as well as the size distribution of the ground product may vary significantly with the nanomechanical response of the material. Thus accurate measurement of crystals' hardness and modulus is essential to determine the ideal operational micronisation conditions of the spiral jet mill. The recently developed nanoindentation technique is applied to examine subsurface properties of pharmaceutical bulk materials, namely calcite, sodium ascorbate, lactose and sodium chloride. Pressing a small sized tip into the material while continuously recording load and displacement, characteristic diagrams are derived. The mathematical evaluation of the force-displacement-data allows for calculation of the hardness and the elastic modulus of the investigated material at penetration depths between 50-300 nm. Grinding experiments performed with a modified spiral jet mill (Type Fryma JMRS 80) indicate the strong impact of the elastic-plastic properties of a given substance on its breaking behaviour. The fineness of milled products produced at constant grinding conditions but with different crystalline powders varies significantly as it is dependent on the

  4. A Sensor Fusion Algorithm for Filtering Pyrometer Measurement Noise in the Czochralski Crystallization Process

    Directory of Open Access Journals (Sweden)

    M. Komperød

    2011-01-01

    Full Text Available The Czochralski (CZ crystallization process is used to produce monocrystalline silicon for solar cell wafers and electronics. Tight temperature control of the molten silicon is most important for achieving high crystal quality. SINTEF Materials and Chemistry operates a CZ process. During one CZ batch, two pyrometers were used for temperature measurement. The silicon pyrometer measures the temperature of the molten silicon. This pyrometer is assumed to be accurate, but has much high-frequency measurement noise. The graphite pyrometer measures the temperature of a graphite material. This pyrometer has little measurement noise. There is quite a good correlation between the two pyrometer measurements. This paper presents a sensor fusion algorithm that merges the two pyrometer signals for producing a temperature estimate with little measurement noise, while having significantly less phase lag than traditional lowpass- filtering of the silicon pyrometer. The algorithm consists of two sub-algorithms: (i A dynamic model is used to estimate the silicon temperature based on the graphite pyrometer, and (ii a lowpass filter and a highpass filter designed as complementary filters. The complementary filters are used to lowpass-filter the silicon pyrometer, highpass-filter the dynamic model output, and merge these filtered signals. Hence, the lowpass filter attenuates noise from the silicon pyrometer, while the graphite pyrometer and the dynamic model estimate those frequency components of the silicon temperature that are lost when lowpass-filtering the silicon pyrometer. The algorithm works well within a limited temperature range. To handle a larger temperature range, more research must be done to understand the process' nonlinear dynamics, and build this into the dynamic model.

  5. Sympathetic cooling of $^4$He$^+$ ions in a radiofrequency trap

    CERN Document Server

    Roth, B; Schiller, S

    2004-01-01

    We have generated Coulomb crystals of ultracold $^4$He$^+$ ions in a linear radiofrequency trap, by sympathetic cooling via laser--cooled $^9$Be$^+$. Stable crystals containing up to 150 localized He$^+$ ions at $\\sim$20 mK were obtained. Ensembles or single ultracold He$^+$ ions open up interesting perspectives for performing precision tests of QED and measurements of nuclear radii. The present work also indicates the feasibility of cooling and crystallizing highly charged atomic ions using $^9$Be$^+$ as coolant.

  6. Intrinsic luminescence and energy transfer processes in pure and doped YVO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pankratov, V.; Grigorjeva, L.; Millers, D. [Institute of Solid State Physics, University of Latvia, Riga (Latvia); Yochum, H.M. [Department of Physics and Engineering, Sweet Briar College, VA (United States)

    2007-03-15

    Luminescence properties of nominally pure and neodymium doped YVO{sub 4} single crystals have been studied by means of time-resolved luminescence spectroscopy technique. It was detected that, besides the main well-known blue excitonic emission band near 2.8 eV, an additional UV emission band at {proportional_to}3.1 eV appears in the spectra of intrinsic luminescence at low temperatures ({proportional_to}80 K) for all crystals studied. Decay time of the UV band is much faster in comparison with the blue one and the UV band is quenched at temperatures above 150 K. Origin of the UV emission band is discussed. A significant rise front was observed in the relaxation kinetics of Nd{sup 3+} emission under band-to-band excitation. The time constant of the rise front of the Nd{sup 3+} emission is very close to decay time of the blue emission in a wide temperature range. It is suggested that the energy transfer process from the host lattice to neodymium ions occurs via excitonic states. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Dense Ge nanocrystal layers embedded in oxide obtained by controlling the diffusion-crystallization process

    Energy Technology Data Exchange (ETDEWEB)

    Lepadatu, Ana-Maria [National Institute of Materials Physics (Romania); Stoica, Toma [Peter Gruenberg Institute (PGI-9), Forschungszentrum Juelich (Germany); Stavarache, Ionel; Teodorescu, Valentin Serban [National Institute of Materials Physics (Romania); Buca, Dan [Peter Gruenberg Institute (PGI-9), Forschungszentrum Juelich (Germany); Ciurea, Magdalena Lidia, E-mail: ciurea@infim.ro [National Institute of Materials Physics (Romania)

    2013-10-15

    Amorphous Ge/SiO{sub 2} multilayer structures deposited by magnetron sputtering have been annealed at different temperatures between 650 and 800 Degree-Sign C for obtaining Ge nanocrystals in oxide matrix. The properties of the annealed structures were investigated by transmission electron microscopy, Raman spectroscopy, and low temperature photoluminescence. The Ge crystallization is partially achieved at 650 Degree-Sign C and increases with annealing temperature. Insight of the Ge nanocrystal formation was acquired by comparing two annealing procedures, i.e., in a conventional tube furnace and by a rapid thermal annealing. By rapid thermal annealing in comparison to conventional furnace one, the Ge crystallization process is faster than Ge diffusion, resulting in the formation of more compact layers of Ge nanocrystals with 8-9.5-nm size as Raman spectroscopy reveals. These findings are important to improve the annealing efficiency in the nanocrystals formation for a precise control of their sizes and location in oxide matrix and for the possibility to create systems with interacting nanoparticles for charge or excitonic transfer. The infrared photoluminescence of Ge nanocrystals at low temperatures shows strong emission with two sharp peaks at about 1,000 meV.

  8. A virtual crystallization furnace for solar silicon

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, I.; Franke, D. [ACCESS e.V., Aachen (Germany); Krumbe, W.; Liebermann, J. [Bayer AG, Krefeld-Uerdingen (Germany)

    1994-12-31

    Blocks of silicon for photovoltaic applications are economically crystallized in large casting furnaces. The quality of the material is determined by the velocity of the crystallization front, the flatness of the liquid-solid interface and the thermal gradients in the solid during cooling. The process cycle time, which is determined by the rate of crystallization and cooling, has a large effect on the process economic viability. Traditionally trial and error was used to determine the process control parameters, the success of which depended on the operator`s experience and intuition. This paper presents a numerical model, which when completed by a fitted data set, constitutes a virtual model of a real crystallization furnace, the Virtual Crystallization Furnace (VCF). The time-temperature distribution during the process cycle is the main output, which includes a display of actual liquid-solid front position. Moreover, solidification velocity, temperature gradients and thermal stresses can be deduced from this output. The time needed to run a simulation on a modern work-station is approximately 1/6 of real process time, thereby allowing the user to make many process variations at very reasonable costs. Therefore the VCF is a powerful tool for optimizing the process in order to reduce cycle time and to increase product quality.

  9. Effect of alumina short fiber and air-cooling processing on solidification microstructure and tensile properties of Al2O3/Al-15Si composites

    Institute of Scientific and Technical Information of China (English)

    张学习; 王德尊; 姚忠凯

    2002-01-01

    The effect of microstructure variation by addition of alumina short fiber and optimization of tensile properties by air-cooling processing in Al2O3/Al-15Si composites were studied. The results show that in Al-15Si alloy matrix composites with 14% and 30%(volume fraction) fiber, the primary silicon is hardly refined, but the eutectic silicon is effectively refined and granulated. Granulation of some eutectic silicon mainly happens in fiber segregation areas. Refining and granulation of the eutectic silicon are related to the physical constraint arising from the fiber. After the 30%Al2O3/Al-15Si composite was remelted and air-cooled, the number of the eutectic silicon on the surface of the fiber increases, which results in the improvement of fiber/matrix interface and tensile properties for the as-cast composite. Air-cooling processing may be reliable for the optimization of the microstructure and properties of fiber reinforced hypereutectic Al-15Si alloy composites.

  10. Effect of annealing cooling rate on microstructure and mechanical property of 100Cr6 steel ring manufactured by cold ring rolling process

    Institute of Scientific and Technical Information of China (English)

    魏文婷; 吴敏

    2014-01-01

    Pre-heat treatment is a vital step before cold ring rolling and it has significant effect on the microstructure and mechanical properties of rolled rings. The 100Cr6 steel rings were subjected to pre-heat treatment and subsequent cold rolling process. Scanning electron microscopy and tensile tests were applied to investigate microstructure characteristic and mechanical property variations of 100Cr6 steel rings undergoing different pre-heat treatings. The results indicate that the average diameter of carbide particles, the tensile strength and hardness increase, while the elongation decreases with the decrease of cooling rate. The cooling rate has minor effect on the yield strength of sample. After cold ring rolling, the ferrite matrix shows a clear direction along the rolling direction. The distribution of cementite is more homogeneous and the cementite particles are finer. Meanwhile, the hardness of the rolled ring is higher than that before rolling.

  11. Radiative cooling for thermophotovoltaic systems

    Science.gov (United States)

    Zhou, Zhiguang; Sun, Xingshu; Bermel, Peter

    2016-09-01

    Radiative cooling has recently garnered a great deal of attention for its potential as an alternative method for photovoltaic thermal management. Here, we will consider the limits of radiative cooling for thermal management of electronics broadly, as well as a specific application to thermal power generation. We show that radiative cooling power can increase rapidly with temperature, and is particularly beneficial in systems lacking standard convective cooling. This finding indicates that systems previously operating at elevated temperatures (e.g., 80°C) can be passively cooled close to ambient under appropriate conditions with a reasonable cooling area. To examine these general principles for a previously unexplored application, we consider the problem of thermophotovoltaic (TPV) conversion of heat to electricity via thermal radiation illuminating a photovoltaic diode. Since TPV systems generally operate in vacuum, convective cooling is sharply limited, but radiative cooling can be implemented with proper choice of materials and structures. In this work, realistic simulations of system performance are performed using the rigorous coupled wave analysis (RCWA) techniques to capture thermal emitter radiation, PV diode absorption, and radiative cooling. We subsequently optimize the structural geometry within realistic design constraints to find the best configurations to minimize operating temperature. It is found that low-iron soda-lime glass can potentially cool the PV diode by a substantial amount, even to below ambient temperatures. The cooling effect can be further improved by adding 2D-periodic photonic crystal structures. We find that the improvement of efficiency can be as much as an 18% relative increase, relative to the non-radiatively cooled baseline, as well as a potentially significant improvement in PV diode lifetime.

  12. Integrated membrane distillation-crystallization: process design and cost estimations for seawater treatment and fluxes of single salt solutions

    NARCIS (Netherlands)

    Creusen, R.J.M.; Medevoort, J. van; Roelands, C.P.M.; Renesse van Duivenbode, J.A.D. van; Hanemaaijer, J.H.; Leerdam, R.C. van

    2013-01-01

    The goal of this research is to design an integrated membrane distillation-crystallization (MDC) process for desalination of seawater with pure water and dry salts as the only products. The process is based on a combination of membrane distillation (MD) and osmotic distillation (OD) steps with

  13. Mathematical modeling of static layer crystallization for propellant grade hydrogen peroxide

    Science.gov (United States)

    Hao, Lin; Chen, Xinghua; Sun, Yaozhou; Liu, Yangyang; Li, Shuai; Zhang, Mengqian

    2017-07-01

    Hydrogen peroxide (H2O2) is an important raw material widely used in many fields. In this work a mathematical model of heat conduction with a moving boundary was proposed to study the melt crystallization process of hydrogen peroxide which was carried out outside a cylindrical crystallizer. Considering the effects of the temperature of the cooling fluid on the thermal conductivity of crude crystal, the model is an improvement of Guardani's research and can be solved by analytic iteration method. An experiment was designed to measure the thickness of crystal layer with time under different conditions. A series of analysis, including the effects of different refrigerant temperature on crystal growth rate, the effects of different cooling rates on crystal layer growth rate, the effects of crystallization temperature on heat transfer and the model's application scope were conducted based on the comparison between experimental results and simulation results of the model.

  14. Nonlinear enhancement in photonic crystal slow light waveguides fabricated using CMOS-compatible process.

    Science.gov (United States)

    Shinkawa, Mizuki; Ishikura, Norihiro; Hama, Yosuke; Suzuki, Keijiro; Baba, Toshihiko

    2011-10-24

    We have studied low-dispersion slow light and its nonlinear enhancement in photonic crystal waveguides. In this work, we fabricated the waveguides using Si CMOS-compatible process. It enables us to integrate spotsize converters, which greatly simplifies the optical coupling from fibers as well as demonstration of the nonlinear enhancement. Two-photon absorption, self-phase modulation and four-wave mixing were observed clearly for picosecond pulses in a 200-μm-long device. In comparison with Si wire waveguides, a 60-120 fold higher nonlinearity was evaluated for a group index of 51. Unique intensity response also occurred due to the specific transmission spectrum and enhanced nonlinearities. Such slow light may add various functionalities in Si photonics, while loss reduction is desired for ensuring the advantage of slow light.

  15. Crystallization Behavior of Anatase Films in Applied Electric Field Heating Process

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this research the TiO2 thin films were prepared by sol-gel dip coating. The crystallization of the films in the applied electric field heating process was thoroughly studied by many technique, differential thermal analysis (DTA), Raman spectroscopy and atomic force microscope (AFM). Furthermore the phase formation, microstructure and photo-catalytic activity of TiO2 film were studied under the condition of an electric field heating-treatment. It is found that the existence of applied electric field promotes the phase transformation from anatase to rutile. Studies on photo-catalytic degradation show that the photo-catalytic activity of TiO2 thin films in an applied electric field is higher.

  16. On chip complex signal processing devices using coupled phononic crystal slab resonators and waveguides

    Directory of Open Access Journals (Sweden)

    Saeed Mohammadi

    2011-12-01

    Full Text Available In this paper, we report the evidence for the possibility of achieving complex signal processing functionalities such as multiplexing/demultiplexing at high frequencies using phononic crystal (PnC slabs. It is shown that such functionalities can be obtained by appropriate cross-coupling of PnC resonators and waveguides. PnC waveguides and waveguide-based resonators are realized and cross-coupled through two different methods of mechanical coupling (i.e., direct coupling and side coupling. Waveguide-based PnC resonators are employed because of their high-Q, compactness, large spurious-free spectral ranges, and the possibility of better control over coupling to PnC waveguides. It is shown that by modifying the defects in the formation of the resonators, the frequency of the resonance can be tuned.

  17. Design of nanoengineered hybrid PVA/PNIPAm/CaCl2/SiO2-Polystyrene (PSt) colloidal crystal hydrogel coatings that sweat/rehydrate H2O from the atmosphere to give sustainable cooling and self-indicate their state

    Science.gov (United States)

    Eloi, Jean-Charles; Worsley, Myles P.; Sermon, Paul A.; Healy, William; Dimech, Christine

    2016-09-01

    The potential for nanoengineering hybrid PVA hydrogel and hydrogel microsphere optical coatings is demonstrated with fine-tuning by the addition of (i) PNIPAm domains, (ii) water-hunting humectant CaCl2, and (ii) polystyrene or SiO2 colloidal crystals. The design and application onto substrates of the hydrogel scaffold is described. The addition of a temperature-triggered component as well as humectant and NIR reflectors are reported. The hybrid hydrogels appeared effective in sustainable adsorption cooling technology (ACT) over sustained periods. It is shown that the thermoresponsive (PNIPAm) domains act as an extra reserve, sweating water above 305K, prolonging the controlled release of water. It is also reported that the addition of humectant is crucial for the natural re-hydration of the hydrogels. For the moment PNIPAm microspheres have only short- lived ACT properties. Finally, coating with microspheres (MSs) in hydrogels produces a visible-NIR reflector effect that may allow optical feedback on ACT.

  18. Electronic excitation energy transfer and nonstationary processes in KH2PO4:Tl crystals

    Science.gov (United States)

    Ogorodnikov, I. N.; Pustovarov, V. A.

    2017-04-01

    We report the results of our experimental study and numerical simulation of the electronic excitation energy transfer to impurity centers under conditions where nonstationary processes take place in the hydrogen sublattice of potassium dihydrogen phosphate (KH2PO4) single crystals doped with mercury-like Tl+ ions (KDP:Tl). We present the experimental results of our investigation of the decay kinetics of the transient optical absorption (100 ns-50 s) of intrinsic defects in the hydrogen sublattice of KDP:Tl obtained by pulsed absorption spectroscopy and the results of our study of the dynamics of the change in steady-state luminescence intensity with irradiation time (1-5000 s). To explain the transfer of the energy being released during electron recombination involving intrinsic KDP:Tl lattice defects, we formulate a mathematical model for the transfer of this energy to impurity Tl+ luminescence centers. Within the model being developed, we present the systems of differential balance equations describing the nonstationary processes in the electron subsystem and the hydrogen sublattice; provide a technique for calculating the pair correlation functions Y( r, t) of dissimilar defects based on the solution of the Smoluchowski equation for the system of mobile hydrogen sublattice defects; calculate the time-dependent reaction rate constants K( t) for various experimental conditions; and outline the peculiarities and results of the model parametrization based on our experimental data. Based on our investigation, the dramatic and significant effect of a gradual inertial increase by a factor of 50-100 in steady-state luminescence intensity in the 4.5-eV band in KDP:Tl crystals due to the luminescence of mercury-like Tl+ ions has been explained qualitatively and quantitatively.

  19. Effect of Copper on the Crystallization Process, Microstructure and Selected Properties of CGI

    Directory of Open Access Journals (Sweden)

    Gumienny G.

    2017-03-01

    Full Text Available The paper presents the results of the research on the effect of copper on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in cast iron was obtained using Inmold process. The study involved the cast iron containing copper at a concentration up to approximately 4%. The effect of copper on the temperature of the eutectic crystallization as well as the temperature of start and finish of the austenite transformation was given. It has been shown that copper increases the maximum temperature of the eutectic transformation approximately by 5°C per 1% Cu, and the temperature of the this transformation finish approximately by 8°C per 1% Cu. This element decreases the temperature of the austenite transformation start approximately by 5°C per 1% Cu, and the finish of this transformation approximately by 6°C per 1% Cu. It was found that in the microstructure of the compacted graphite iron containing about 3.8% Cu, there are still ferrite precipitations near the compacted graphite. The effect of copper on the hardness of cast iron and the pearlite microhardness was given. This stems from the high propensity to direct ferritization of this type of cast iron. It has been shown copper increases the hardness of compacted graphite iron both due to its pearlite forming action as well as because of the increase in the pearlite microhardness (up to approx. 3% Cu. The conducted studies have shown copper increases the hardness of the compacted graphite iron approximately by 35 HB per 1% Cu.

  20. Processing of X-ray snapshots from crystals in random orientations

    Energy Technology Data Exchange (ETDEWEB)

    Kabsch, Wolfgang, E-mail: kabsch@mpimf-heidelberg.mpg.de [Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, D-69120 Heidelberg (Germany)

    2014-08-01

    A new method for the treatment of partial reflections from X-ray snapshots is implemented in the program package nXDS, which yields intensity data of almost the same quality as those obtained by the classical rotation method. A functional expression is introduced that relates scattered X-ray intensities from a still or a rotation snapshot to the corresponding structure-factor amplitudes. The new approach was implemented in the program nXDS for processing monochromatic diffraction images recorded by a multi-segment detector where each exposure could come from a different crystal. For images containing indexable spots, the intensities of the expected reflections and their variances are obtained by profile fitting after mapping the contributing pixel contents to the Ewald sphere. The varying intensity decline owing to the angular distance of the reflection from the surface of the Ewald sphere is estimated using a Gaussian rocking curve. This decline is dubbed ‘Ewald offset correction’, which is well defined even for still images. Together with an image-scaling factor and other corrections, an explicit expression is defined that predicts each recorded intensity from its corresponding structure-factor amplitude. All diffraction parameters, scaling and correction factors are improved by post-refinement. The ambiguous case of a lower point group than the lattice symmetry is resolved by a method reminiscent of the technique of ‘selective breeding’. It selects the indexing alternative for each image that yields, on average, the highest correlation with intensities from all other images. Processing a test set of rotation images by XDS and treating the same images by nXDS as snapshots of crystals in random orientations yields data of comparable quality, clearly indicating an anomalous signal from Se atoms.

  1. 砂再生与砂冷却工艺装备的技术创新%The innovation of the sand regeneration and sand cooling process equipment

    Institute of Scientific and Technical Information of China (English)

    吴剑

    2015-01-01

    the paper introduces the casting process and the new development of the old sand regeneration and cooling process equipment technical characteristics. Sand regeneration, sand cooling and the application state of typical process equipment is analyzed. Provide process and technical support for the regeneration of foundry sand. Expand the development direction of the casting process equipment and production application.%介绍了近几年自硬砂工艺应用中新研发应用的旧砂再生、冷却工艺装备的技术特性.分析了自硬砂铸造工艺应用中砂再生、砂冷却及典型工艺装备的应用状态.为铸造业砂再生提供工艺及技术支持,拓展铸造工艺装备与生产应用的创新发展思路.

  2. Process design and simulation for optimizing the oxygen concentration in Czochralski-grown single-crystal silicon

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Y. J.; Kim, W. K.; Jung, J. H. [Yeungnam University, Gyeongsan (Korea, Republic of)

    2014-08-15

    The highest-concentration impurity in a single-crystal silicon ingot is oxygen, which infiltrates the ingot during growth stage. This oxygen adversely affects the wafer is quality. This study was aimed at finding an optimal design for the Czochralski (Cz) process to enable high-quality and low cost (by reducing power consumption) wafer production by controlling the oxygen concentration in the silicon ingots. In the Cz process, the characteristics of silicon ingots during crystallization are greatly influenced by the design and the configuration of the hot zone, and by crystallization rate. In order to identify process conditions for obtaining an optimal oxygen concentration of 11 - 13 ppma (required for industrial-grade ingots), designed two shield shapes for the hot zone. Furthermore, oxygen concentrations corresponding to these two shapes were compared by evaluating each shape at five different production speeds. In addition, simulations were performed to identify the optimal shield design for industrial applications.

  3. Laser Cooling of Molecular Anions

    CERN Document Server

    Yzombard, Pauline; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-01-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.

  4. Laser cooling of molecular anions.

    Science.gov (United States)

    Yzombard, Pauline; Hamamda, Mehdi; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-05-29

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarize the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C_{2}^{-}, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photodetachment process is present, as well as Doppler laser cooling of trapped C_{2}^{-}, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources, and antimatter physics.

  5. Semantic modeling of the structural and process entities during plastic deformation of crystals and rocks

    Science.gov (United States)

    Babaie, Hassan; Davarpanah, Armita

    2016-04-01

    We are semantically modeling the structural and dynamic process components of the plastic deformation of minerals and rocks in the Plastic Deformation Ontology (PDO). Applying the Ontology of Physics in Biology, the PDO classifies the spatial entities that participate in the diverse processes of plastic deformation into the Physical_Plastic_Deformation_Entity and Nonphysical_Plastic_Deformation_Entity classes. The Material_Physical_Plastic_Deformation_Entity class includes things such as microstructures, lattice defects, atoms, liquid, and grain boundaries, and the Immaterial_Physical_Plastic_Deformation_Entity class includes vacancies in crystals and voids along mineral grain boundaries. The objects under the many subclasses of these classes (e.g., crystal, lattice defect, layering) have spatial parts that are related to each other through taxonomic (e.g., Line_Defect isA Lattice_Defect), structural (mereological, e.g., Twin_Plane partOf Twin), spatial-topological (e.g., Vacancy adjacentTo Atom, Fluid locatedAlong Grain_Boundary), and domain specific (e.g., displaces, Fluid crystallizes Dissolved_Ion, Void existsAlong Grain_Boundary) relationships. The dynamic aspect of the plastic deformation is modeled under the dynamical Process_Entity class that subsumes classes such as Recrystallization and Pressure_Solution that define the flow of energy amongst the physical entities. The values of the dynamical state properties of the physical entities (e.g., Chemical_Potential, Temperature, Particle_Velocity) change while they take part in the deformational processes such as Diffusion and Dislocation_Glide. The process entities have temporal parts (phases) that are related to each other through temporal relations such as precedes, isSubprocessOf, and overlaps. The properties of the physical entities, defined under the Physical_Property class, change as they participate in the plastic deformational processes. The properties are categorized into dynamical, constitutive

  6. Irradiation damage in Gd2Ti2O7 single crystals: Ballistic versus ionization processes

    Science.gov (United States)

    Moll, S.; Sattonnay, G.; Thomé, L.; Jagielski, J.; Decorse, C.; Simon, P.; Monnet, I.; Weber, W. J.

    2011-08-01

    The structural transformations induced in Gd2Ti2O7 single crystals irradiated at high energies (870-MeV Xe), where ionization processes (electronic stopping) dominate, and at low energies (4-MeV Au), where ballistic processes (nuclear stopping) dominate, have been studied via the combination of Rutherford backscattering spectrometry and channeling (RBS/C), Raman spectroscopy, and transmission electron microscopy (TEM) experiments. At high energy, amorphization occurs directly in individual ion tracks from the extreme electronic-energy deposition, and full amorphization results from the overlapping of these tracks as described by a direct impact model. The track diameters lie in the range 6-9 nm. At low energy, amorphization occurs via indirect processes, driven by ballistic nuclear energy deposition from the ions, that is accounted for in the framework of both direct-impact/defect-stimulated and multi-step damage accumulation models. The ion fluence for total amorphization of the irradiated layer is much higher at low energy (0.5 ion nm-2) than at high energy (0.05 ion nm-2), consistent with the nuclear stopping at low energy (5.2 keV/nm) compared to the electronic stopping at high energy (29 keV/nm).

  7. Irradiation Damage in Gd2Ti2O7 Single Crystals: Ballistic vs Ionization Processes

    Energy Technology Data Exchange (ETDEWEB)

    Moll, Sandra [Pacific Northwest National Laboratory (PNNL); Sattonnay, Gael [Universite Paris Sud, Orsay, France; Thome, Lionel [Universite Paris Sud, Orsay, France; Jagielski, Jacek [Institute for Electronic Materials Technology; Decorse, C [Universite Paris Sud, Orsay, France; Simon, Patrick [CEMHTI-CNRS, Universite d' Orleans; Monnet, Isabelle [Grand Accelerateur National d' Ions Lourds (GANIL); Weber, William J [ORNL

    2011-01-01

    The structural transformations induced in Gd2Ti2O7 single crystals irradiated at high energies (870 MeV Xe), where ionization processes (electronic stopping) dominate, and at low energies (4 MeV Au), where ballistic processes (nuclear stopping) dominate, have been studied via the combination of Rutherford backscattering spectrometry and channeling, Raman spectroscopy and transmission electron microscopy experiments. At high energy, amorphization occurs directly in individual ion tracks from the extreme electronic energy deposition from ionization, and full amorphization results from the overlapping of these tracks as described by a direct impact model. The track diameters determined from RBS/C and TEM data lie in the range 6-8 nm. At low energy, amorphization occurs via indirect processes, driven by ballistic nuclear energy deposition from the ions, that is accounted for in the framework of both the direct-impact/defect stimulated and multi-step damage accumulation models. The ion fluence for total amorphization of the irradiated layer is much higher (0.5 ion nm-2) at low energy than at high energy (0.05 ion nm-2), consistent with the nuclear stopping at low energy (5.2 keV/nm) compared to the electronic stopping at high energy (29 keV/nm).

  8. Ventilative Cooling

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Kolokotroni, Maria

    This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state-of-the-art of ventil......This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state...

  9. Super Massive Star Clusters: From Superwinds to a Cooling Catastrophe and the Re-processing of the Injected Gas

    CERN Document Server

    Silich, S; Muñoz-Tunón, C; Palous, J

    2006-01-01

    Different hydrodynamic regimes for the gaseous outflows generated by multiple supernovae explosions and stellar winds occurring within compact and massive star clusters are discussed. It is shown that there exists the threshold energy that separates clusters whose outflows evolve in the quasi-adiabatic or radiative regime from those within which catastrophic cooling and a positive feedback star-forming mode sets in. The role of the surrounding ISM and the observational appearance of the star cluster winds evolving in different hydrodynamic regimes are also discussed.

  10. Sympathetic cooling and detection of a hot trapped ion by a cold one

    CERN Document Server

    Guggemos, M; Herrera-Sancho, O A; Blatt, R; Roos, C F

    2015-01-01

    We investigate the dynamics of an ion sympathetically cooled by another laser-cooled ion or small ion crystal. To this end, we develop simple models of the cooling dynamics in the limit of weak Coulomb interactions. Experimentally, we create a two-ion crystal of Ca$^+$ and Al$^+$ by photo-ionization of neutral atoms produced by laser ablation. We characterize the velocity distribution of the laser-ablated atoms crossing the trap by time-resolved fluorescence spectroscopy. We observe neutral atom velocities much higher than the ones of thermally heated samples and find as a consequence long sympathethic cooling times before crystallization occurs. Our key result is a new technique for detecting the loading of an initially hot ion with energy in the eV range by monitoring the motional state of a Doppler-cooled ion already present in the trap. This technique not only detects the ion but also provides information about dynamics of the sympathetic cooling process.

  11. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J.; Zhang, Yanliang

    2016-09-01

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

  12. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J.; Zhang, Yanliang

    2016-01-01

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications. PMID:27615036

  13. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals.

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J; Zhang, Yanliang

    2016-09-12

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm(2) with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

  14. Crystal Structure of the HEAT Domain from the Pre-mRNA Processing Factor Symplekin

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Sarah A.; Frazier, Monica L.; Steiniger, Mindy; Mast, Ann M.; Marzluff, William F.; Redinbo, Matthew R.; (UNC)

    2010-09-30

    The majority of eukaryotic pre-mRNAs are processed by 3'-end cleavage and polyadenylation, although in metazoa the replication-dependent histone mRNAs are processed by 3'-end cleavage but not polyadenylation. The macromolecular complex responsible for processing both canonical and histone pre-mRNAs contains the {approx} 1160-residue protein Symplekin. Secondary-structural prediction algorithms identified putative HEAT domains in the 300 N-terminal residues of all Symplekins of known sequence. The structure and dynamics of this domain were investigated to begin elucidating the role Symplekin plays in mRNA maturation. The crystal structure of the Drosophila melanogaster Symplekin HEAT domain was determined to 2.4 {angstrom} resolution with single-wavelength anomalous dispersion phasing methods. The structure exhibits five canonical HEAT repeats along with an extended 31-amino-acid loop (loop 8) between the fourth and fifth repeat that is conserved within closely related Symplekin sequences. Molecular dynamics simulations of this domain show that the presence of loop 8 dampens correlated and anticorrelated motion in the HEAT domain, therefore providing a neutral surface for potential protein-protein interactions. HEAT domains are often employed for such macromolecular contacts. The Symplekin HEAT region not only structurally aligns with several established scaffolding proteins, but also has been reported to contact proteins essential for regulating 3'-end processing. Together, these data support the conclusion that the Symplekin HEAT domain serves as a scaffold for protein-protein interactions essential to the mRNA maturation process.

  15. Trapping and Sympathetic Cooling of Boron Ions

    CERN Document Server

    Rugango, Rene; Shu, Gang; Brown, Kenneth R

    2016-01-01

    We demonstrate the trapping and sympathetic cooling of B$^{+}$ ions in a Coulomb crystal of laser-cooled Ca$^{+}$, We non-destructively confirm the presence of the both B$^+$ isotopes by resonant excitation of the secular motion. The B$^{+}$ ions are loaded by ablation of boron and the secular excitation spectrum also reveals features consistent with ions of the form B$_{n}^{+}$.

  16. Cool snacks

    DEFF Research Database (Denmark)

    Grunert, Klaus G; Brock, Steen; Brunsø, Karen

    2016-01-01

    such a product requires an interdisciplinary effort where researchers with backgrounds in psychology, anthropology, media science, philosophy, sensory science and food science join forces. We present the COOL SNACKS project, where such a blend of competences was used first to obtain thorough insight into young...

  17. Utilization of ice regenerative heat system for cooling process in manufacturing bean curd, and realization of productivity enhancement as well as cost reduction; Tofu seizo no reikyaku kotei ni kori chikunetsu system wo katsuyoshi, seisansei kojo to costdown wo jitsugen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-10-01

    There is a process of cooling a product finished at high temperature in the manufacturing of bean curd. The temperature reaches 60-70 degrees C in the center of the bean curd just finished. In the conventional process, bean curd used to be cooled by ground water, by keeping the bean curd for along time in the temperature range of 30-40 degrees C which is liable to growth of miscellaneous bacteria. Instead, a rapid cooling method was employed using an ice regenerative system. This cooling system by an ice regenerative heat pump is such that ice made by night electricity is stored in a heat storage tank and that the ice is used as cooling water at 2 degree C during the daytime. Consequently, it can contribute to the reduction of cooling time and to the suppression of bacteria growth. Naturally, being rapid cooling, the method does not spoil the flavor of bean curd. Moreover, since the operation is fully automatic, there is no need to assign a man specially for the operation, while the cold water is ready to be used immediately from the start. In addition, the cooling temperature is constant, with less amount of water serving the purpose. An industrial regenerative adjustment contract makes it possible to use electricity at the economical night rate and to contrive a large reduction in cost. (NEDO)

  18. An Investigation into the Polymorphism and Crystallization of Levetiracetam and the Stability of its Solid Form.

    Science.gov (United States)

    Xu, Kailin; Xiong, Xinnuo; Guo, Liuqi; Wang, Lili; Li, Shanshan; Tang, Peixiao; Yan, Jin; Wu, Di; Li, Hui

    2015-12-01

    Levetiracetam (LEV) crystals were prepared using different solvents at different temperatures. The LEV crystals were systematically characterized by X-ray powder diffraction (XRPD) and morphological analysis. The results indicated that many kinds of crystal habits exist in a solid form of LEV. To investigate the effects of LEV concentration, crystallization temperature, and crystallization type on crystallization and solid phase transformation of LEV, multiple methods were performed for LEV aqueous solution to determine if a new solid form exists in solid-state LEV. However, XRPD data demonstrate that the LEV solid forms possess same spatial arrangements that are similar to the original solid form. This result indicates that the LEV concentration, crystallization temperature, and crystallization type in aqueous solution have no influence on the crystallization and solid phase transformation of LEV. Moreover, crystallization by sublimation, melt cooling, and quench cooling, as well as mechanical effect, did not result in the formation of new LEV solid state. During melt cooling, the transformation of solid form LEV is a direct process from melting amorphous phase to the original LEV crystal phase, and the conversion rate is very quick. In addition, stability investigation manifested that LEV solid state is very stable under various conditions.

  19. Effect of surfactants or a water soluble polymer on the crystal transition of clarithromycin during a wet granulation process.

    Science.gov (United States)

    Nozawa, Kenji; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2015-11-10

    To generate products containing a stable form of clarithromycin (CAM) (form II) regardless of the initial crystal form of CAM or type of granulation solvent, the effects of five surfactants, or a water-soluble polymer (macrogol 400) were determined on the crystal transition of CAM. The metastable form (form I) was kneaded with water, after adding surfactants, or a water-soluble polymer. Form II was also kneaded with ethanol, after adding the same additives. The resulting samples were analyzed by powder X-ray diffraction. Form I was completely converted to form II by a wet granulation using water with additives bearing polyoxyethylene chains such as polysorbate 80 (PS80), polyoxyl 40 stearate or macrogol 400. The granulation of the form II using ethanol with these additives did not result in a crystal transition to form I. Furthermore, CAM tablets were manufactured using granules with PS80, and these crystal forms and dissolution behaviors were investigated. As a result, the wet granulation of CAM with PS80 gave CAM tablets containing only form II and PS80 did not have any adverse effects on tablet characteristics. Therefore, these data suggests that the crystal form of CAM can be controlled to be form II using a wet granulation process with additives bearing polyoxyethylene chains regardless of the initial crystal form of CAM or type of granulation solvent. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Effects of short immersion time and cooling rates of copperizing process to the evolution of microstructures and copper behavior in the dead mild steel

    Science.gov (United States)

    Jatimurti, Wikan; Sutarsis, Cunika, Aprida Ulya

    2017-01-01

    In a dead mild steel with maximum carbon content of 0.15%, carbon does not contribute much to its strength. By adding copper as an alloying element, a balance between strength and ductility could be obtained through grain refining, solid solution, or Cu precipitation. This research aimed to analyse the changes in microstructures and copper behaviour on AISI 1006, including the phases formed, composition, and Cu dispersion. The addition of cooper was done by immersing steel into molten copper or so we called, copperizing using the principles of diffusion. Specimens were cut with 6 × 3 × 0.3 cm measurement then preheated to 900°C and melting the copper at 1100°C. Subsequently, the immersion of the specimens into molten copper varied to 5 and 7 minutes, and also varying the cooling rate to annealing, normalizing, and quenching. A series of test being conduct were optical microscope test, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), optical emission spectroscopy (OES), and X-ray diffraction (XRD). The results showed that the longer the immersion time and slower cooling rate, the more Cu diffused causing smaller grain size with the highest Cu diffused recorded was 0.277% in the copperized AISI 1006 steel with 7 minutes of immersion and was annealed. The grain size reduced to 23041.5404 µm2. The annealed specimens show ferrite phase, the normalized ones show polygonal ferrite phase, while the quenched ones show granular bainite phase. The phase formed is single phase Cu. In addition, the normalized and quenched specimens show that Cu dissolved in Fe crystal forming solid solution.