WorldWideScience

Sample records for freeze substitution fixation-based

  1. Applicable technical method for freeze-substitution of high pressure ...

    African Journals Online (AJOL)

    bmshsj

    2011-11-02

    Quintana, 1994) are available for the microscopic visualization of intracellular organelles. Cryo- fixation, plunge freezing, propane jet freezing, cold metal block freezing, and high pressure freezing provide advantages over chemical ...

  2. Enhanced resolution of membranes in cultured cells by cryoimmobilization and freeze-substitution.

    Science.gov (United States)

    Wild, P; Schraner, E M; Adler, H; Humbel, B M

    2001-05-15

    Investigations of cellular processes demand immediate arresting of the process at any given time and excellent retention of cellular material and excellent visibility of membranes. To achieve this goal we used cryofixation to arrest cellular processes instantly and tested diverse freeze-substitution protocols. Madin-Darby kidney cells and Vero cells were grown on carbon-coated sapphire disks. For cryofixation the sapphire disks covered with a cell monolayer were injected with the aid of a guillotine into liquid propane or ethane or a mixture of both cooled by liquid nitrogen. Freezing of the cryogen was prevented by using a partially insulated cylinder and by vigorous stirring that results in a substantial decrement of the freezing point of the cryogen. Cell monolayers can be cryofixed successfully using the guillotine in a safety hood at ambient temperature and humidity or at 37 degrees C and 45% humidity. The freezing unit can also be placed in a laminar flow for working under biohazard conditions. For visualizing cell membranes at high contrast and high resolution, cells were substituted in the presence of various concentrations of glutaraldehyde and osmium tetroxide and the temperature was raised to diverse final temperatures. Substitution for 4 hours at -90 degrees C in anhydrous acetone containing 0.25% anhydrous glutaraldehyde and 0.5% osmium tetroxide followed by a temperature rise of 5 degrees C/hour to 0 degrees C and final incubation for 1 hour at 0 degrees C resulted in high contrast and excellent visibility of subcellular components at the level of the membrane bilayer. The high spatial and temporal resolution makes this methodology an excellent tool for studying cell membrane-bound processes, such as virus-cell interactions. Copyright 2001 Wiley-Liss, Inc.

  3. Influence of waxy rice flour substitution for wheat flour on characteristics of batter and freeze-thawed cake.

    Science.gov (United States)

    Jongsutjarittam, Nisachon; Charoenrein, Sanguansri

    2013-09-12

    This study aimed to improve the freeze-thawed cake properties by10-20% waxy rice flour (WRF) substitution for wheat flour (WF). Viscosity of WRF-substituted batters was lower; consequently, trapped air was less uniformly distributed than WF batter. After five freeze-thaw cycles, firmness and enthalpy of melting retrograded amylopectin of WF- and WRF-substituted cakes increased and the matrix surrounding the air pores from SEM images was denser than in fresh-baked cakes. Sensory evaluation showed an increase in firmness and a decrease in firmness acceptability of freeze-thawed cakes. However, freeze-thawed cake with WRF substitution had significantly less firmness, less dense matrix and more acceptability than WF cake. This could have been due to a low amylose content of WRF and the spread of ruptured waxy rice starch granules around swollen wheat starch granules as observed by CLSM. Thus, WRF could be used for WF substitution to improve the firmness in freeze-thawed cake. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Quantitative aspects of enzyme histochemistry on sections of freeze-substituted glycol methacrylate-embedded rat liver

    NARCIS (Netherlands)

    Frederiks, W. M.; Bosch, K. S.

    1993-01-01

    Freeze-substituted rat liver embedded in glycol methacrylate (GMA) has been used to demonstrate the activities of several enzymes. The following enzymes could be detected in GMA-sections by the indicated histochemical procedure(s): 5'-nucleotidase (lead salt, cerium-diaminobenzidine), alkaline

  5. Freeze-substitution methods for Ni localization and quantitative analysis in Berkheya coddii leaves by means of PIXE

    International Nuclear Information System (INIS)

    Budka, D.; Mesjasz-PrzybyIowicz, J.; Tylko, G.; PrzybyIowicz, W.J.

    2005-01-01

    Leaves of Ni hyperaccumulator Berkheya coddii were chosen as a model to investigate the influence of eight freeze-substitution protocols on the Ni content and distribution. Freeze-substitution of leaf samples cryofixed by high-pressure freezing was carried out in dry acetone, methanol, diethyl ether and tetrahydrofuran. The same substitution media were also used with dimethylglyoxime added as a precipitation reagent. The samples were infiltrated and embedded in Spurr's resin. Micro-PIXE analysis of Ni concentration and localization, complemented by proton backscattering for matrix assessment, was performed using the nuclear microprobe at Materials Research Group, iThemba LABS, South Africa. True elemental maps and concentrations were obtained using GeoPIXE-II software. The results were compared with the control results obtained for the parallel air-dried samples, corrected for the water content. The highest Ni content was found in the leaf samples substituted in diethyl ether. This concentration was statistically different from the results obtained for other media. In case of diethyl ether medium Ni was mainly localized in the mesophyll tissue, and the distribution map of this element was in accordance with previous results obtained for freeze-dried and frozen-hydrated leaves of this species. The same distribution pattern was observed for specimens embedded in dry acetone, but Ni concentration was significantly lower. Tetrahydrofuran medium preserved Ni preferentially in the epidermis and vascular tissue, and the elemental map for samples embedded in this medium was distorted. Ni was almost completely washed out from samples substituted in methanol and it was thus impossible to obtain a picture of its distribution. Dimethylglyoxime did not improve the preservation of this element. These results show that diethyl ether is a suitable substitution medium for assessment of Ni concentration and distribution in leaves of B. coddii

  6. High-resolution visualization of Pseudomonas aeruginosa PAO1 biofilms by freeze-substitution transmission electron microscopy.

    Science.gov (United States)

    Hunter, Ryan C; Beveridge, Terry J

    2005-11-01

    High-pressure freeze-substitution and transmission electron microscopy have been used for high-resolution imaging of the natural structure of a gram-negative biofilm. Unlike more conventional embedding techniques, this method confirms many of the observations seen by confocal microscopy but with finer structural detail. It further reveals that there is a structural complexity to biofilms at both the cellular and extracellular matrix levels that has not been seen before. Different domains of healthy and lysed cells exist randomly dispersed within a single biofilm as well as different structural organizations of exopolymers. Particulate matter is suspended within this network of fibers and appears to be an integral part of the exopolymeric substance (EPS). O-side chains extending from the outer membrane are integrated into EPS polymers so as to form a continuum. Together, the results support the concept of physical microenvironments within biofilms and show a complexity that was hitherto unknown.

  7. Effect of the Winter Wheat Cheyenne 5A Substituted Chromosome on Dynamics of Abscisic Acid and Cytokinins in Freezing-Sensitive Chinese Spring Genetic Background

    Science.gov (United States)

    Kalapos, Balázs; Novák, Aliz; Dobrev, Petre; Vítámvás, Pavel; Marincs, Ferenc; Galiba, Gábor; Vanková, Radomira

    2017-01-01

    The effect of short- and long-term cold treatment on the abscisic acid (ABA) and cytokinin (CK) metabolism, and their main biosynthesis- and signaling-related genes were investigated in freezing-sensitive and freezing-tolerant wheat genotypes. Varieties Cheyenne and Chinese Spring substituted with the 5A Cheyenne chromosome, which represented freezing-tolerant genotypes, were compared with the freezing-sensitive Chinese Spring. Hormone levels and gene expression data indicated that the short- and long-term cold treatments are associated with specific regulation of the accumulation of cold-protective proteins and phytohormone levels, as well as the expression profiles of the hormone-related genes. The significant differences were observed between the genotypes, and between their leaf and crown tissues, too. The level of dehydrins, including WCS120 protein, and expression of WCS120 gene were considerably higher in the freezing-tolerant genotypes after 21 days of cold treatment. Expression of Cor14b and CBF14, cold-responsive regulator genes, was increased by cold treatment in all genotypes, to higher extent in freezing-tolerant genotypes. Cluster analysis revealed that the tolerant genotypes had a similar response to cold treatment, regarding expression of the ABA and CK metabolic genes, as well as hormone levels in leaves. As far as hormone levels in crowns are concerned, however, the strongly freezing-tolerant Cheyenne variety clustered separately from the Chinese Spring and the substitution line, which were more similar to each other after both 1 and 21 days of cold treatment than to Cheyenne. Based on these results we concluded that the 5A chromosome of wheat might have both a direct and an indirect impact on the phytohormone-dependent cold-induced freezing tolerance. Based on the gene expression data, novel genetic markers could be developed, which may be used to determine the freezing tolerance level in a wide range of wheat varieties. PMID:29238355

  8. Effects of different fixation and freeze substitution methods on the ultrastructural preservation of ZYMV-infected Cucurbita pepo (L.) leaves.

    Science.gov (United States)

    Zechmann, Bernd; Müller, Maria; Zellnig, Günther

    2005-08-01

    Different fixation protocols [chemical fixation, plunge and high pressure freezing (HPF)] were used to study the effects of Zucchini yellow mosaic virus (ZYMV) disease on the ultrastructure of adult leaves of Styrian oil pumpkin plants (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) with the transmission electron microscope. Additionally, different media were tested for freeze substitution (FS) to evaluate differences in the ultrastructural preservation of cryofixed plant leaf cells. FS was either performed in (i) 2% osmium tetroxide in anhydrous acetone containing 0.2% uranyl acetate, (ii) 0.01% safranin in anhydrous acetone, (iii) 0.5% glutaraldehyde in anhydrous acetone or (iv) anhydrous acetone. No ultrastructural differences were found in well-preserved cells of plunge and high pressure frozen samples. Cryofixed cells showed a finer granulated cytosol and smoother membranes, than what was found in chemically fixed samples. HPF led in comparison to plunge frozen plant material to an excellent preservation of vascular bundle cells. The use of FS-media such as anhydrous acetone, 0.01% safranin and 0.5% glutaraldehyde led to low membrane contrast and did not preserve the inner fine structures of mitochondria. Additionally, the use of 0.5% glutaraldehyde caused the cytosol to be fuzzy and partly loosened. ZYMV-induced ultrastructural alterations like cylindrical inclusions and dilated ER-cisternae did not differ between chemically fixed and cryofixed cells and were found within the cytosol of infected leaf cells and within sieve tube elements. The results demonstrate specific structural differences depending on the FS-medium used, which has to be considered for investigations of selected cell structures.

  9. Effect of chemical fixatives on accurate preservation of Escherichia coli and Bacillus subtilis structure in cells prepared by freeze-substitution

    International Nuclear Information System (INIS)

    Graham, L.L.; Beveridge, T.J.

    1990-01-01

    Five chemical fixatives were evaluated for their ability to accurately preserve bacterial ultrastructure during freeze-substitution of select Escherichia coli and Bacillus subtilis strains. Radioisotopes were specifically incorporated into the peptidoglycan, lipopolysaccharide, and nucleic acids of E. coli SFK11 and W7 and into the peptidoglycan and RNA of B. subtilis 168 and W23. The ease of extraction of radiolabels, as assessed by liquid scintillation counting during all stages of processing for freeze-substitution, was used as an indicator of cell structural integrity and retention of cellular chemical composition. Subsequent visual examination by electron microscopy was used to confirm ultrastructural conformation. The fixatives used were: 2% (wt/vol) osmium tetroxide and 2% (wt/vol) uranyl acetate; 2% (vol/vol) glutaraldehyde and 2% (wt/vol) uranyl acetate; 2% (vol/vol) acrolein and 2% (wt/vol) uranyl acetate; 2% (wt/vol) gallic acid; and 2% (wt/vol) uranyl acetate. All fixatives were prepared in a substitution solvent of anhydrous acetone. Extraction of cellular constituents depended on the chemical fixative used. A combination of 2% osmium tetroxide-2% uranyl acetate or 2% gallic acid alone resulted in optimum fixation as ascertained by least extraction of radiolabels. In both gram-positive and gram-negative organisms, high levels of radiolabel were detected in the processing fluids in which 2% acrolein-2% uranyl acetate, 2% glutaraldehyde-2% uranyl acetate, or 2% uranyl acetate alone were used as fixatives. Ultrastructural variations were observed in cells freeze-substituted in the presence of different chemical fixatives. We recommend the use of osmium tetroxide and uranyl acetate in acetone for routine freeze-substitution of eubacteria, while gallic acid is recommended for use when microanalytical processing necessitates the omission of osmium

  10. Effect of the winter wheat cheyenne 5A substituted chromosome on dynamics of abscisic acid and cytokinins in freezing-sensitive Chinese spring genetic background

    Czech Academy of Sciences Publication Activity Database

    Kalapos, S.; Novák, A.; Dobrev, Petre; Vítámvás, P.; Marincs, F.; Galiba, G.; Vaňková, Radomíra

    2017-01-01

    Roč. 8, NOV 29 (2017), č. článku 2033. ISSN 1664-462X R&D Projects: GA ČR(CZ) GA17-06613S; GA MZe QJ1530373 Institutional support: RVO:61389030 Keywords : Abscisic acid * Cold treatment * Cytokinin * Freezing tolerance * Gene expression * Phytohormones * Triticum aestivum Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 4.298, year: 2016

  11. Freezing Bubbles

    Science.gov (United States)

    Kingett, Christian; Ahmadi, Farzad; Nath, Saurabh; Boreyko, Jonathan

    2017-11-01

    The two-stage freezing process of a liquid droplet on a substrate is well known; however, how bubbles freeze has not yet been studied. We first deposited bubbles on a silicon substrate that was chilled at temperatures ranging from -10 °C to -40 °C, while the air was at room temperature. We observed that the freeze front moved very slowly up the bubble, and in some cases, even came to a complete halt at a critical height. This slow freezing front propagation can be explained by the low thermal conductivity of the thin soap film, and can be observed more clearly when the bubble size or the surface temperature is increased. This delayed freezing allows the frozen portion of the bubble to cool the air within the bubble while the top part is still liquid, which induces a vapor pressure mismatch that either collapses the top or causes the top to pop. In cases where the freeze front reaches the top of the bubble, a portion of the top may melt and slowly refreeze; this can happen more than just once for a single bubble. We also investigated freezing bubbles inside of a freezer where the air was held at -20 °C. In this case, the bubbles freeze quickly and the ice grows radially from nucleation sites instead of perpendicular to the surface, which provides a clear contrast with the conduction limited room temperature bubbles.

  12. Freezing for Love

    DEFF Research Database (Denmark)

    Carroll, Katherine; Kroløkke, Charlotte

    2018-01-01

    The promise of egg freezing for women’s fertility preservation entered feminist debate in connection with medical and commercial control over, and emancipation from, biological reproduction restrictions. In this paper we explore how women negotiate and make sense of the decision to freeze...... their eggs. Our analysis draws on semi-structured interviews with 16 women from the Midwest and East Coast regions of the USA who froze their eggs. Rather than freezing to balance career choices and ‘have it all’, the women in this cohort were largely ‘freezing for love’ and in the hope of having their ‘own...... healthy baby’. This finding extends existing feminist scholarship and challenges bioethical concerns about egg freezing by drawing on the voices of women who freeze their eggs. By viewing egg freezing as neither exclusively liberation nor oppression or financial exploitation, this study casts egg freezing...

  13. Surface freezing of water

    OpenAIRE

    P?rez-D?az, J. L.; ?lvarez-Valenzuela, M. A.; Rodr?guez-Celis, F.

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered?exclusively?by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on ...

  14. 3 CFR - Pay Freeze

    Science.gov (United States)

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Pay Freeze Presidential Documents Other Presidential Documents Memorandum of January 21, 2009 Pay Freeze Memorandum for the Assistant to the President and Chief... the White House staff forgo pay increases until further notice. Accordingly, as a signal of our shared...

  15. The Freezing Bomb

    Science.gov (United States)

    Mills, Allan

    2010-01-01

    The extreme pressures that are generated when water freezes were traditionally demonstrated by sealing a small volume in a massive cast iron "bomb" and then surrounding it with a freezing mixture of ice and salt. This vessel would dramatically fail by brittle fracture, but no quantitative measurement of bursting pressure was available. Calculation…

  16. Surface freezing of water.

    Science.gov (United States)

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

  17. Freeze drying method

    International Nuclear Information System (INIS)

    Coppa, N.V.; Stewart, P.; Renzi, E.

    1999-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser

  18. Complications are reduced with a protocol to standardize timing of fixation based on response to resuscitation.

    Science.gov (United States)

    Vallier, Heather A; Moore, Timothy A; Como, John J; Wilczewski, Patricia A; Steinmetz, Michael P; Wagner, Karl G; Smith, Charles E; Wang, Xiao-Feng; Dolenc, Andrea J

    2015-10-01

    Our group developed a protocol, entitled Early Appropriate Care (EAC), to determine timing of definitive fracture fixation based on presence and severity of metabolic acidosis. We hypothesized that utilization of EAC would result in fewer complications than a historical cohort and that EAC patients with definitive fixation within 36 h would have fewer complications than those treated at a later time. Three hundred thirty-five patients with mean age 39.2 years and mean Injury Severity Score (ISS) 26.9 and 380 fractures of the femur (n = 173), pelvic ring (n = 71), acetabulum (n = 57), and/or spine (n = 79) were prospectively evaluated. The EAC protocol recommended definitive fixation within 36 h if lactate <4.0 mmol/L, pH ≥7.25, or base excess (BE) ≥-5.5 mmol/L. Complications including infections, sepsis, DVT, organ failure, pneumonia, acute respiratory distress syndrome (ARDS), and pulmonary embolism (PE) were identified and compared for early and delayed patients and with a historical cohort. All 335 patients achieved the desired level of resuscitation within 36 h of injury. Two hundred sixty-nine (80%) were treated within 36 h, and 66 had protocol violations, treated on a delayed basis, due to surgeon choice in 71%. Complications occurred in 16.3% of patients fixed within 36 h and in 33.3% of delayed patients (p = 0.0009). Hospital and ICU stays were shorter in the early group: 9.5 versus 17.3 days and 4.4 versus 11.6 days, respectively, both p < 0.0001. This group of patients when compared with a historical cohort of 1443 similar patients with 1745 fractures had fewer complications (16.3 versus 22.1%, p = 0.017) and shorter length of stay (LOS) (p = 0.018). Our EAC protocol recommends definitive fixation within 36 h in resuscitated patients. Early fixation was associated with fewer complications and shorter LOS. The EAC recommendations are safe and effective for the majority of severely injured patients with mechanically

  19. Freeze-drying and related preparation techniques for biological microprobe analysis

    International Nuclear Information System (INIS)

    Wroblewski, R.; Wroblewski, J.; Anniko, M.; Edstroem, L.P.

    1985-01-01

    An X-ray microanalytical and morphological investigation has been carried out on rapidly frozen, freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerization procedures following freeze-substitution and freeze-drying. The investigation also included an analysis of specimens infiltrated, embedded and polymerized by ultraviolet irradiation at low temperatures with Lowicryl HM20. The morphological preservation of Lowicryl embedded tissue was adequate for the identification of different cell structures like nuclei, mitochondria, lysosomes and different types of endoplasmic reticulum. X-ray microanalytical investigation of low temperature embedded material displayed an elemental composition of cells and organelles similar to that found in freeze-dried cyosections. Compared with freeze-dried cryosections, low temperature embedded material could be sectioned for light microscopy and area of interest chosen for further thin sectioning. This is of great importance in work with tissues with complicated morphology and heterogenous cell populations

  20. Polymerization with freezing

    International Nuclear Information System (INIS)

    Ben-Naim, E; Krapivsky, P L

    2005-01-01

    Irreversible aggregation processes involving reactive and frozen clusters are investigated using the rate equation approach. In aggregation events, two clusters join irreversibly to form a larger cluster; additionally, reactive clusters may spontaneously freeze. Frozen clusters do not participate in merger events. Generally, freezing controls the nature of the aggregation process, as demonstrated by the final distribution of frozen clusters. The cluster mass distribution has a power-law tail, F k ∼k -γ , when the freezing process is sufficiently slow. Different exponents, γ = 1 and 3, are found for the constant and the product aggregation rates, respectively. For the latter case, the standard polymerization model, either no gels, or a single gel, or even multiple gels, may be produced

  1. Stiffness Analysis of the Sarafix External Fixator based on Stainless Steel and Composite Material

    Directory of Open Access Journals (Sweden)

    Nedim Pervan

    2015-11-01

    Full Text Available This paper describes a structural analysis of the CAD model three versions fixators Sarafix which is to explore the possibility of introducing composite materials in the construction of the connecting rod fixators comparing values of displacement and stiffness at characteristic structure points. Namely, we have investigated the constructional performance of fixators Sarafix with a connecting rod formed from three different composite materials, the same matrix (epoxy resin with three different types of fibers (E glass, kevlar 49 and carbonM55J. The results of the structural analysis fixators Sarafix with a connecting rod made of composite materials are compared with the results of tubular connecting rod fixators made of stainless steel. After comparing the results, from the aspect of stiffness, we gave the final considerations about composite material which provides an adequate substitution for the existing material.

  2. Substitutional analysis

    CERN Document Server

    Rutherford, Daniel Edwin

    2013-01-01

    Classic monograph, suitable for advanced undergraduates and graduate students. Topics include calculus of permutations and tableaux, semi-normal representation, orthogonal and natural representations, group characters, and substitutional equations. 1968 edition.

  3. The value of a freeze

    International Nuclear Information System (INIS)

    Bethe, H.A.; Long, F.A.

    1988-01-01

    This paper reports on the rapid increase in public support for a nuclear-freeze agreement---that is, a mutual freeze on the testing, production and further deployment of nuclear weapons---which has been a remarkable political phenomenon. In less than a year, support has grown from a few volunteers collecting signatures on petitions to a congressional vote in which supporters of a freeze very nearly prevailed. This fall, eight states and the District of Columbia will vote on freeze referendums. Already Wisconsin voters have overwhelmingly voted yes in such a referendum. There are many reasons for this strong support for a freeze, including fear of nuclear war, resistance to high levels of military spending and opposition to particular military policies of the Reagan administration. But to most supporters, the chief purpose of a freeze is simple: it is to help stop an immense, continuing, dangerous and incredibly costly arms race between the two superpowers

  4. Operator substitution

    NARCIS (Netherlands)

    Hautus, M.L.J.

    1994-01-01

    Substitution of an operator into an operator-valued map is defined and studied. A Bezout-type remainder theorem is used to derive a number of results. The tensor map is used to formulate solvability conditions for linear matrix equations. Some applications to system theory are given, in particular

  5. Solvent substitution

    International Nuclear Information System (INIS)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general ''Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated

  6. Tonemic Substitution

    African Journals Online (AJOL)

    Ezenwafor

    grammatical constructions. The choice of substitutable tonemes as observed from the analyzed data is highly. Ezenwafordependent on the intuitive judgement of the native speaker. This work shows with adequate data, that regular tonemic changes are not always meaningful in Ekwulobia lect. Such tonemic alternations are ...

  7. Solvent substitution

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  8. Influence of the geometry on magnetic interactions in a retina fixator based on a magnetoactive elastomer seal

    Science.gov (United States)

    Nadzharyan, T. A.; Makarova, L. A.; Kazimirova, E. G.; Perov, N. S.; Kramarenko, E. Yu

    2018-03-01

    We study the effects the geometric configuration has on magnetic interactions between a magnetoactive elastomer (MAE) sample and various systems of permanent magnets for problems with both flat and curved geometry. MAEs consist of a silicone polymer matrix and iron filler microparticles embedded in it. Permanent magnets are cylindrical neodymium magnets arranged in a line on a flat or curved solid surfaces. We use computer simulations, namely the finite element method, in order to study the interaction force and magnetic pressure in a system with an MAE sample and permanent magnets. The model is based on classical Maxwell magnetostatics and two factors taking into account field dependence of MAE’s magnetic properties and inhomogeneities caused by local demagnetization. We calculate magnetic pressure dependences on various geometric parameters of the system, namely, the diameter and the height of permanent magnets, the distance between the magnets and dimensions of MAE samples. This research aims to create a set of guidelines for choosing the geometric configuration of a retina fixator based on MAE seals to be used in eye surgery for retinal detachment treatment.

  9. Freeze Protection in Gas Holders

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Duursma, Gail

    In cold weather, the water seals of gasholders need protection from freez- ing to avoid compromising the seal. These holders have a large reservoir of “tank water” at the base which is below ground. At present freeze- protection is achieved by external heating of the seal water which...

  10. Generalized structural theory of freezing

    International Nuclear Information System (INIS)

    Yussouff, M.

    1980-10-01

    The first-principles order parameter theory of freezing, proposed in an earlier work, has been successful in yielding quantitative agreement with known freezing parameters for monoatomic liquids forming solids with one atom per unit cell. A generalization of this theory is presented here to include the effects of a basis set of many atoms per unit cell. The basic equations get modified by the 'density structure factors' fsub(i) which arise from the density variations within the unit cell. Calculations are presented for the important case of monoatomic liquids freezing into hexagonal close packed solids. It is concluded that all freezing transitions can be described by using structural correlations in the liquid instead of the pair potential; and that the three body correlations are important in deciding the type of solid formed after freezing. (author)

  11. Refurbishing of a Freeze Drying Machine, used in Nuclear Medicine for Radiopharmaceuticals Production

    International Nuclear Information System (INIS)

    Gaytan-Gallardo, E.; Desales-Galeana, G.

    2006-01-01

    The refurbishing of a freeze drying machine used in the radiopharmaceuticals production, applied in nuclear medicine in the Radioactive Materials Department of the Nuclear Research National Institute in Mexico (ININ in Spanish), is presented. The freeze drying machine was acquired in the 80's decade and some components started having problems. Then it was necessary to refurbish this equipment by changing old cam-type temperature controllers and outdated recording devices, developing a sophisticated software system that substitutes those devices. The system is composed by a freeze drying machine by Hull, AC output modules for improved temperature control, a commercial data acquisition card, and the software system

  12. Momentum anisotropy at freeze out

    International Nuclear Information System (INIS)

    Feld, S.; Borghini, N.; Lang, C.

    2017-01-01

    The transition from a hydrodynamical modeling to a particle-based approach is a crucial element of the description of high-energy heavy-ion collisions. Assuming this “freeze out” happens instantaneously at each point of the expanding medium, we show that the local phase-space distribution of the emitted particles is asymmetric in momentum space. This suggests the use of anisotropic hydrodynamics for the last stages of the fluid evolution. We discuss how observables depend on the amount of momentum-space anisotropy at freeze out and how smaller or larger anisotropies allow for different values of the freeze-out temperature. (paper)

  13. Anhydrobiosis and Freezing-Tolerance

    DEFF Research Database (Denmark)

    McGill, Lorraine; Shannon, Adam; Pisani, Davide

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode...... Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth...

  14. FREEZE DRYING PROCESS: A REVIEW

    OpenAIRE

    Soham Shukla

    2011-01-01

    Among the various methods of drying, this article has mentioned only one most important method, “Freeze drying”. This method is mainly used for the drying of thermo labile materials. This method works on the principle of sublimation. This method is divided into 3 steps for its better understanding; these are Freezing, Primary drying, and secondary drying. There are many advantages and disadvantages of this method, but still this is the most useful drying method nowadays.

  15. A Theory of Immersion Freezing

    Science.gov (United States)

    Barahona, Donifan

    2017-01-01

    Immersion freezing is likely involved in the initiation of precipitation and determines to large extent the phase partitioning in convective clouds. Theoretical models commonly used to describe immersion freezing in atmospheric models are based on the classical nucleation theory which however neglects important interactions near the immersed particle that may affect nucleation rates. This work introduces a new theory of immersion freezing based on two premises. First, immersion ice nucleation is mediated by the modification of the properties of water near the particle-liquid interface, rather than by the geometry of the ice germ. Second, the same mechanism that leads to the decrease in the work of germ formation also decreases the mobility of water molecules near the immersed particle. These two premises allow establishing general thermodynamic constraints to the ice nucleation rate. Analysis of the new theory shows that active sites likely trigger ice nucleation, but they do not control the overall nucleation rate nor the probability of freezing. It also suggests that materials with different ice nucleation efficiency may exhibit similar freezing temperatures under similar conditions but differ in their sensitivity to particle surface area and cooling rate. Predicted nucleation rates show good agreement with observations for a diverse set of materials including dust, black carbon and bacterial ice nucleating particles. The application of the new theory within the NASA Global Earth System Model (GEOS-5) is also discussed.

  16. Medical and social egg freezing

    DEFF Research Database (Denmark)

    Lallemant, Camille; Vassard, Ditte; Andersen, Anders Nyboe

    2016-01-01

    INTRODUCTION: Until recently, limited options for preserving fertility in order to delay childbearing were available. Although egg freezing and successful thawing is now possible, it remains unclear to what extent women are aware of the availability of this technique, their attitudes towards its...... use, or the circumstances under which this technique may be considered. MATERIAL AND METHODS: An online cross-sectional survey was designed to investigate knowledge and attitudes of women in Denmark and the UK on egg freezing and their potential intentions regarding the procedure. RESULTS: Data...... was collected from September 2012 to September 2013 and the responses of 973 women were analyzed. In total, 83% of women reported having heard of egg freezing, and nearly all considered it acceptable for medical indications, whilst 89% considered it acceptable for social reasons. Overall, 19% expressed active...

  17. Freeze-dried microarterial allografts

    International Nuclear Information System (INIS)

    Raman, J.; Hargrave, J.C.

    1990-01-01

    Rehydrated freeze-dried microarterial allografts were implanted to bridge arterial defects using New Zealand White rabbits as the experimental model. Segments of artery from the rabbit ear and thigh were harvested and preserved for a minimum of 2 weeks after freeze-drying. These allografts, approximately 1 mm in diameter and ranging from 1.5 to 2.5 cm in length, were rehydrated and then implanted in low-pressure and high-pressure arterial systems. Poor patency was noted in low-pressure systems in both allografts and autografts, tested in 12 rabbits. In the high-pressure arterial systems, allografts that were freeze-dried and reconstituted failed in a group of 10 rabbits with an 8-week patency rate of 30 percent. Gamma irradiation in an effort to reduce infection and antigenicity of grafts after freeze-drying was associated with a patency rate of 10 percent at 8 weeks in this system in another group of 10 rabbits. Postoperative cyclosporin A therapy was associated with a patency rate of 22.2 percent in the high-pressure arterial system in a 9-rabbit group. Control autografts in this system in a group of 10 rabbits showed a 100 percent patency at 8 weeks. Microarterial grafts depend on perfusion pressure of the vascular bed for long-term patency. Rehydrated freeze-dried microarterial allografts do not seem to function well in lengths of 1 to 2.5 cm when implanted in a high-pressure arterial system. Freeze-dried arterial allografts are probably not antigenic

  18. Simple, heart-smart substitutions

    Science.gov (United States)

    Coronary artery disease - heart smart substitutions; Atherosclerosis - heart smart substitutions; Cholesterol - heart smart substitutions; Coronary heart disease - heart smart substitutions; Healthy diet - heart ...

  19. Effect of magnetic field on food freezing

    OpenAIRE

    村田, 圭治; 奥村, 太一; 荒賀, 浩一; 小堀, 康功

    2010-01-01

    [Abstract] This paper presents an experimental investigation on effects of magnetic field on food freezing process. Although purpose of food freezing is to suppress the deterioration of food, freezing breaks food tissue down, and some nutrient and delicious element flow out after thawing. Recently, a few of refrigeration equipments with electric and magnetic fields have attracted attention from food production companies and mass media. Water and tuna were freezed in magnetic field (100kH, 1.3...

  20. Freeze out in heavy ion reactions

    International Nuclear Information System (INIS)

    Csernai, Laszlo P.; Lazar, Zs.I.; Grassi, F.; Hama, Y.

    1998-01-01

    In fluid dynamical models the freeze out of particles across a three dimensional space-time hypersurface is discussed. The calculation of final momentum distribution of emitted particles is described for freeze out surfaces, with both space-like and time-like normals, taking into account conservation laws across the freeze out discontinuity. Generally the conservation laws lead to a change of temperature, baryon density and flow velocity at freeze out. (author)

  1. Quality changes and freezing time prediction during freezing and thawing of ginger

    OpenAIRE

    Singha, Poonam; Muthukumarappan, Kasiviswanathan

    2015-01-01

    Abstract Effects of different freezing rates and four different thawing methods on chemical composition, microstructure, and color of ginger were investigated. Computer simulation for predicting the freezing time of cylindrical ginger for two different freezing methods (slow and fast) was done using ANSYS ? Multiphysics. Different freezing rates (slow and fast) and thawing methods significantly (P?

  2. 9 CFR 590.536 - Freezing operations.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Freezing operations. 590.536 Section 590.536 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG..., and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  3. 9 CFR 590.534 - Freezing facilities.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Freezing facilities. 590.534 Section 590.534 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG..., and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the...

  4. Impregnation of leather during "freeze-drying"

    DEFF Research Database (Denmark)

    Storch, Mikkel; Vestergaard Poulsen Sommer, Dorte; Hovmand, Ida

    2016-01-01

    Freeze-drying is a recognized method for the preservation of waterlogged objects. Naturally, freeze-drying has also been used for waterlogged archaeological leather often after treatment with Na2.EDTA and impregnation with PEG; but the treated leather sometimes suffers from “excessive drying......” becoming too stiff and brittle. The aim of this study was to examine the effect of a conventional freeze-drying method against an alternative freeze-drying method that preserves the natural moisture content of the leather. Both new and archaeological waterlogged leather were included in the study...... suggest that the process which takes place within the leather during the freeze-drying in not actual freeze-drying, but rather a sophisticated way of distributing the impregnating agent. The pure ice phase freezes out, but the impregnating agent remains liquid as the temperature does not become low enough...

  5. Freeze-casting: Fabrication of highly porous and hierarchical ceramic supports for energy applications

    Directory of Open Access Journals (Sweden)

    Cyril Gaudillere

    2016-03-01

    The aim of this paper is to give an overview of the freeze-casting ceramic shaping method and to show how its implementation could be useful for several energy applications where key components comprise a porous scaffold. A detailed presentation of the freeze-casting process and of the characteristics of the resulting porous parts is firstly given. The characteristic of freeze-cast parts and the drawbacks of conventional porous scaffolds existing in energy applications are drawn in order to highlight the expected beneficial effect of this new shaping technique as possible substitute to the conventional ones. Finally, a review of the state of the art freeze-cast based energy applications developed up to now and expected to be promising is given to illustrate the large perspectives opened by the implementation of the freeze-casting of ceramics for energy fields. Here we suggest discussing about the feasibility of incorporate freeze-cast porous support in high temperature ceramic-based energy applications.

  6. Transition from natural-convection-controlled freezing to conduction-controlled freezing

    International Nuclear Information System (INIS)

    Sparrow, E.M.; Ramsey, J.W.; Harris, J.S.

    1981-01-01

    Experiments were performed to study the transition between freezing controlled by natural convection in the liquid adjacent to a freezing interface and freezing controlled by heat conduction in the solidified material. The freezing took place on a cooled vertical tube immersed in an initially superheated liquid contained in an adiabatic-walled vessel. At early and intermediate times, temperature differences throughout the liquid induce a vigorous natural convection motion which retards freezing, but the temperature differences diminish with time and natural convection ebbs. At large times, the freezing rate is fully controlled by heat conduction in the solidified material. The frozen specimens for short and intermediate freezing times are smooth-surfaced and tapered, while those for large times are straight-sided and have surfaces that are overlaid with a thicket of large discrete crystals. These characteristics correspond respectively to those of natural-convection- controlled freezing and conduction-controlled freezing. At early times, the measured mass of the frozen material is identical to that for natural-convection-controlled freezing and conduction-controlled freezing. At early times, the measured mass of the frozen material is identical to that for natural-convection-controlled freezing. At later times, the frozen mass tends to approach that for conduction-controlled freezing, but a residual deficit remains

  7. Sequential Strangeness Freeze-out

    Science.gov (United States)

    Bellwied, Rene

    2018-02-01

    I will describe the latest results from lattice QCD pertaining to a potential flavour hierarchy in the hadronic freeze-out from the QCD crossover region. I will compare these results to a variety of improved hadronic resonance gas calculations and to experimental data of fluctuations of net-charge, net-proton and net-kaon multiplicity distributions, which serve as a proxy for the susceptibilities of conserved quantum numbers on the lattice. I will conclude that there is intriguing evidence for a flavour dependent freezeout, and I will suggest expansions to the experimental program at RHIC and the LHC that could potentially demonstrate the impact of a flavour separation during hadronization.

  8. Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy

    Science.gov (United States)

    Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to u...

  9. Freeze dehydration of milk using microwave energy

    International Nuclear Information System (INIS)

    Souda, K.B.; Akyel, C.; Bilgen, E.

    1989-01-01

    This paper presents the results of experimental studies on heat and mass transfer during a microwave freeze dehydration process. An experimental system and procedure was developed to freeze dry milk. A 2500-W microwave system with an appropriate wave guide was set up and instrumented, and a procedure was experimentally developed to obtain milk powder first by freezing milk and then dehydrating it at low pressure using microwave energy. An unsteady-state analysis was used to derive a one-dimensional mathematical model of the freeze dehydration process in a microwave electromagnetic field

  10. A comparison of freezing-damage during isochoric and isobaric freezing of the potato

    OpenAIRE

    Lyu, Chenang; Nastase, Gabriel; Ukpai, Gideon; Serban, Alexandru; Rubinsky, Boris

    2017-01-01

    Background Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freez...

  11. Mechanisms of deterioration of nutrients. [of freeze dried foods

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1976-01-01

    Methods which produce freeze dried foods of improved quality were examined with emphasis on storage stability. Specific topics discussed include: microstructure of freeze dried systems, investigation of structural changes in freeze dried systems, artificial food matrices, osmotic preconcentration to yield improved quality freeze dried fruits, and storage stability of osmotically preconcentrated freeze dried fruits.

  12. Freeze concentration of lime juice

    Directory of Open Access Journals (Sweden)

    Ampawan Tansakul

    2008-11-01

    Full Text Available The main objective of this research was to study the effects of processing conditions, i.e. cooling medium temperature (-6, -12 and -18C and scraper blade rotational speed (50, 100 and 150 rpm on the freeze concentration of lime juice. The initial soluble solid content of lime juice was 7.6 Brix. Results showed that soluble solid content of lime juice increased as cooling medium temperature decreased while scraper blade rotational speed increased. It was also found that the processing condition with -18˚C cooling medium temperature and 150 rpm rotational speed of the scraper blade was the best among all studied conditions, although the loss of the soluble solids with ice crystals during ice separation was relatively high at 35%.

  13. Bioinspired Design: Magnetic Freeze Casting

    Science.gov (United States)

    Porter, Michael Martin

    Nature is the ultimate experimental scientist, having billions of years of evolution to design, test, and adapt a variety of multifunctional systems for a plethora of diverse applications. Next-generation materials that draw inspiration from the structure-property-function relationships of natural biological materials have led to many high-performance structural materials with hybrid, hierarchical architectures that fit form to function. In this dissertation, a novel materials processing method, magnetic freeze casting, is introduced to develop porous scaffolds and hybrid composites with micro-architectures that emulate bone, abalone nacre, and other hard biological materials. This method uses ice as a template to form ceramic-based materials with continuously, interconnected microstructures and magnetic fields to control the alignment of these structures in multiple directions. The resulting materials have anisotropic properties with enhanced mechanical performance that have potential applications as bone implants or lightweight structural composites, among others.

  14. Freezing during tapping tasks in patients with advanced Parkinson's disease and freezing of gait.

    Science.gov (United States)

    Delval, Arnaud; Defebvre, Luc; Tard, Céline

    2017-01-01

    Parkinson's disease patients with freezing of gait also experience sudden motor blocks (freezing) during other repetitive motor tasks. We assessed the proportion of patients with advanced PD and freezing of gait who also displayed segmental "freezing" in tapping tasks. Fifteen Parkinson's disease patients with freezing of gait were assessed. Freezing of gait was evaluated using a standardized gait trajectory with the usual triggers. Patients performed repetitive tapping movements (as described in the MDS-UPDRS task) with the hands or the feet in the presence or absence of a metronome set to 4 Hz. Movements were recorded with a video motion system. The primary endpoint was the occurrence of segmental freezing in these tapping tasks. The secondary endpoints were (i) the relationship between segmental episodic phenomena and FoG severity, and (ii) the reliability of the measurements. For the upper limbs, freezing was observed more frequently with a metronome (21% of trials) than without a metronome (5%). For the lower limbs, the incidence of freezing was higher than for the upper limbs, and was again observed more frequently in the presence of an auditory cue (47%) than in its absence (14%). Although freezing of the lower limbs was easily assessed during an MDS-UPDRS task with a metronome, it was not correlated with the severity of freezing of gait (as evaluated during a standardized gait trajectory). Only this latter was a reliable measurement in patients with advanced Parkinson's disease.

  15. Medicineringsfejl ved generisk substitution

    DEFF Research Database (Denmark)

    Rölfing, Jan

    2012-01-01

    Generic substitution is a major cause of medical mistakes in the general population. Danish legislation obligates pharmacies to substitute prescribed medicine with the cheapest equivalent formulation, despite variations in product name, packaging, shape and colour. Consequently, medical mistakes...... occur. Scientific evidence on the consequences of generic substitution is sparse. Call upon fellow health workers to report medical mistakes to the national entities and scientific peers, in order to increase awareness and scientific evidence about the problem....

  16. Well-plate freeze-drying

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Rantanen, Jukka; Grohganz, Holger

    2015-01-01

    Abstract Context: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. Objective: The aim of this study was to evaluate freeze-drying in well-plates as a h......Abstract Context: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. Objective: The aim of this study was to evaluate freeze-drying in well......-plates as a high throughput platform for formulation screening of freeze-dried products. Methods: Model formulations consisting of mannitol, sucrose and bovine serum albumin were freeze-dried in brass well plates, plastic well plates and vials. Physical properties investigated were solid form, residual moisture......, cake collapse and reconstitution time. Results: Samples freeze-dried in well-plates had an acceptable visual cake appearance. Solid form analysis by high throughput X-ray powder diffraction indicated comparable polymorphic outcome independent of the container. The expected increase in moisture level...

  17. Using Power Ultrasound to Accelerate Food Freezing Processes: Effects on Freezing Efficiency and Food Microstructure.

    Science.gov (United States)

    Zhang, Peizhi; Zhu, Zhiwei; Sun, Da-Wen

    2018-05-31

    Freezing is an effective way of food preservation. However, traditional freezing methods have the disadvantages of low freezing efficiency and generation of large ice crystals, leading to possible damage of food quality. Power ultrasound assisted freezing as a novel technique can effectively reduce the adverse effects during freezing process. This paper gives an overview on recent researches of power ultrasound technique to accelerate the food freezing processes and illustrates the main principles of power ultrasound assisted freezing. The effects of power ultrasound on liquid food, model solid food as well as fruit and vegetables are discussed, respectively, from the aspects of increasing freezing rate and improving microstructure. It is shown that ultrasound assisted freezing can effectively improve the freezing efficiency and promote the formation of small and evenly distributed ice crystals, resulting in better food quality. Different inherent properties of food samples affect the effectiveness of ultrasound application and optimum ultrasound parameters depend on the nature of the samples. The application of ultrasound to the food industry is more likely on certain types of food products and more efforts are still needed to realize the industrial translation of laboratory results.

  18. Hot big bang or slow freeze?

    Science.gov (United States)

    Wetterich, C.

    2014-09-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze - a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple ;crossover model; without a big bang singularity. In the infinite past space-time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  19. Microbiological evaluation of anatomical organs submitted to glycerinization and freeze-drying techniques

    Directory of Open Access Journals (Sweden)

    Marianna Justo

    2016-06-01

    Full Text Available Alternatives conservation techniques are being requested with the proposal of formaldehyde substitution. Formaldehyde results in excessive anatomical specimens' weight and it can cause serious health problems to the manipulator, such as cancer. However, it provides an efficient germicide and fungicide action depending on concentration. The substitute techniques are glicerinization and freeze-drying which have advantages such as non-production of smells, lightness of the organs and dispenses the use of fixatives in conservation. As well as both intrinsic and extrinsic factors interfere in microbial growth, microbiological analyzes are essential to detect possible deteriorative microorganisms in organs and concluding effectively the technique used. Formalinized, glycerinated and freeze-drying organs were collected in three different times which were intercalated by two months, except formalinization that had one evaluation. The procedure required the use of sterilized swabs wetted in peptone water and molds measuring 5,0 cm x 10,0 cm positioned on two different piece's local resulting in 100 cm2 of area, to spread plate of total moulds, mesophiles (except in freeze-drying, psychrophilic (only in freeze-drying and Pseudomonas sp (except in formalinization. All the plates were counted and compared between each technique's evaluations by variance analyzes. Both alternatives techniques resulted in zero or in very low microbial quantity to cause health problems as well as it preserve pieces morphology. All values of all analyzes resulted below 1/ml, showing that glicerinization and freeze-drying techniques are so as efficient as formaldehyde. Keywords: Organs conservation, Anatomical techniques, Microbiology, Microbial growth

  20. Freezing and refrigerated storage in fisheries

    National Research Council Canada - National Science Library

    Johnston, W. A

    1994-01-01

    ...; the factors affecting cold storage conditions, etc. In addition, the publication describes the methods used to calculate cold storage refrigeration loads as well as the costs of freezing and cold storage...

  1. Freezing tolerance of conifer seeds and germinants.

    Science.gov (United States)

    Hawkins, B J; Guest, H J; Kolotelo, D

    2003-12-01

    Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation

  2. Bulk water freezing dynamics on superhydrophobic surfaces

    Science.gov (United States)

    Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

    2017-01-01

    In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

  3. Cognitive Factors Affecting Freeze-like Behavior in Humans.

    Science.gov (United States)

    Alban, Michael W; Pocknell, Victoria

    2017-01-01

    Contemporary research on survival-related defensive behaviors has identified physiological markers of freeze/flight/fight. Our research focused on cognitive factors associated with freeze-like behavior in humans. Study 1 tested if an explicit decision to freeze is associated with the psychophysiological state of freezing. Heart rate deceleration occurred when participants chose to freeze. Study 2 varied the efficacy of freezing relative to other defense options and found "freeze" was responsive to variations in the perceived effectiveness of alternative actions. Study 3 tested if individual differences in motivational orientation affect preference for a "freeze" option when the efficacy of options is held constant. A trend in the predicted direction suggested that naturally occurring cognitions led loss-avoiders to select "freeze" more often than reward-seekers. In combination, our attention to the cognitive factors affecting freeze-like behavior in humans represents a preliminary step in addressing an important but neglected research area.

  4. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Science.gov (United States)

    2010-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject to...

  5. Freezing the Master Production Schedule Under Rolling Planning Horizons

    OpenAIRE

    V. Sridharan; William L. Berry; V. Udayabhanu

    1987-01-01

    The stability of the Master Production Schedule (MPS) is a critical issue in managing production operations with a Material Requirements Planning System. One method of achieving stability is to freeze some portion or all of the MPS. While freezing the MPS can limit the number of schedule changes, it can also produce an increase in production and inventory costs. This paper examines three decision variables in freezing the MPS: the freezing method, the freeze interval length, and the planning ...

  6. Synthesis, processing behavior, and characterization of bismuth superconductors using freeze dried nitrate precursors

    International Nuclear Information System (INIS)

    Coppa, N.V.; Hults, W.L.; Smith, J.L.; Brynestad, J.

    1994-01-01

    The synthesis of Bi 2-x Pb x Sr 2 Ca 2 Cu 3 O 10 (Bi2223) powders from a freeze dried nitrate precursor is reported here. We examine the composition and morphology of the precursor material, describe the chemistry and kinetics of product formation, and evaluate the phase composition and superconducting properties of the products. A nitrate solution containing the appropriate ratio of cations was rapidly frozen and then freeze dried at low temperatures to form an atomic mixture of the component salts. The thermal processing of the freeze dried material consisted of three steps: (i) dehydration, (ii) denitration, and (iii) solid state reaction to form the Bi2223 superconducting product. Calcium substituted bismuthates and strontium-substituted calcium cuprate, not Bi2201, are the intermediates between the nitrates and the superconducting products. These highly disordered phases rapidly transform into Bi2212 or Bi2223 at higher temperatures (>790 degree C). The kinetics of product formation was studied using XRD analysis and magnetic susceptibility. The kinetics were shown to follow the nucleation and growth mechanism. Bi2223 formed after only 30 min at a few degrees below the melting point, and after 37 h Bi2223 products exhibited excellent phase composition and magnetic susceptibility characteristics

  7. Electricity/oil substitution

    International Nuclear Information System (INIS)

    Melvin, J.G.

    1980-09-01

    The extent to which electricity could substitute for imported oil in Canada is assessed and it is concluded that the bulk of projected oil imports could be displaced. This substitution of electricity for oil could be largely completed within two decades, with existing technology, using Canadian resources. The substitution of electricity for imported oil would result in relatively low energy costs and would stimulate economic growth. Energy self-sufficiency through the substitution of electricity for oil is uniquely a Canadian option; it is not open to other industrial countries. The option exists because of Canada's resources of oil sands for essential liquid fuels, hydraulic and nuclear electrical potential, and natural gas as an interim source of energy. While other countries face an energy crisis due to declining supplies of oil, Canada faces opportunities. The policies of Federal and Provincial governments, as perceived by individual decision makers, will have a major influence on Canada's ability to realize opportunities. (auth)

  8. Advantages of liquid nitrogen freezing of Penaeus monodon over conventional plate freezing

    OpenAIRE

    Chakrabarti, R.; Chaudhury, D.R.

    1987-01-01

    Liquid nitrogen frozen products are biochemically and organoleptically superior to conventional plate frozen products but beneficial effect of liquid nitrogen freezing over conventional plate freezing can exist only up to 59 days at a commercial storage temperature of -18°C.

  9. Building the Method to Determine the Rate of Freezing Water in Penaeus monodon of the Freezing Process

    OpenAIRE

    Nguyen Tan Dzung; Trinh Van Dzung; Tran Duc Ba

    2012-01-01

    The method of determination the rate of freezing water in Penaeus monodon of freezing process was established on base the equation of energy balance in warming up process Penaeus monodon after freezing to determine specific heat of Penaeus monodon. The result obtained was built the mathematical model (19) to determine the rate of freezing water according to the freezing temperature of Penaeus monodon. The results indicated that when water was completely frozen (ω = 1 or 100%), the optimal fre...

  10. Freezing of Lennard-Jones-type fluids

    International Nuclear Information System (INIS)

    Khrapak, Sergey A.; Chaudhuri, Manis; Morfill, Gregor E.

    2011-01-01

    We put forward an approximate method to locate the fluid-solid (freezing) phase transition in systems of classical particles interacting via a wide range of Lennard-Jones-type potentials. This method is based on the constancy of the properly normalized second derivative of the interaction potential (freezing indicator) along the freezing curve. As demonstrated recently it yields remarkably good agreement with previous numerical simulation studies of the conventional 12-6 Lennard-Jones (LJ) fluid [S.A.Khrapak, M.Chaudhuri, G.E.Morfill, Phys. Rev. B 134, 052101 (2010)]. In this paper, we test this approach using a wide range of the LJ-type potentials, including LJ n-6 and exp-6 models, and find that it remains sufficiently accurate and reliable in reproducing the corresponding freezing curves, down to the triple-point temperatures. One of the possible application of the method--estimation of the freezing conditions in complex (dusty) plasmas with ''tunable'' interactions--is briefly discussed.

  11. Hot big bang or slow freeze?

    Energy Technology Data Exchange (ETDEWEB)

    Wetterich, C.

    2014-09-07

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  12. Heat transfer coefficient of cryotop during freezing.

    Science.gov (United States)

    Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

    2013-01-01

    Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).

  13. Hot big bang or slow freeze?

    International Nuclear Information System (INIS)

    Wetterich, C.

    2014-01-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe

  14. Storage of human platelets by freezing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B K; Tanoue, K; Baldini, M G

    1976-01-01

    Prolonged, probably indefinite storage of viable and functional human platelets is now possible by freezing with dimethylsulfoxide (DMSO). The platelets have a nearly normal survival upon reinfusion and are capable of sustained hemostatic effectiveness in thrombocytopenic patients. Adaptation of the freezing technique for large-scale usage has more recently been achieved. The method is mainly based on the following principles: (1) use of plasma for suspension of the platelet concentrate; (2) gradual addition (0.5% every 2 min) of DMSO to a final concentration of 5% and its gradual removal; (3) a slow cooling rate of about 1/sup 0/C per min and rapid thawing (in 1 min); (4) use of a polyolefin plastic bag for freezing; (5) a washing medium of 20% plasma in Hanks' balanced salt solution; (6) final resuspension of the platelets in 50% plasma in Hanks' solution.

  15. Hot big bang or slow freeze?

    Directory of Open Access Journals (Sweden)

    C. Wetterich

    2014-09-01

    Full Text Available We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  16. Repeated freeze-thaw cycles reduce the survival rate of osteocytes in bone-tendon constructs without affecting the mechanical properties of tendons.

    Science.gov (United States)

    Suto, Kaori; Urabe, Ken; Naruse, Kouji; Uchida, Kentaro; Matsuura, Terumasa; Mikuni-Takagaki, Yuko; Suto, Mitsutoshi; Nemoto, Noriko; Kamiya, Kentaro; Itoman, Moritoshi

    2012-03-01

    Frozen bone-patellar tendon bone allografts are useful in anterior cruciate ligament reconstruction as the freezing procedure kills tissue cells, thereby reducing immunogenicity of the grafts. However, a small portion of cells in human femoral heads treated by standard bone-bank freezing procedures survive, thus limiting the effectiveness of allografts. Here, we characterized the survival rates and mechanisms of cells isolated from rat bones and tendons that were subjected to freeze-thaw treatments, and evaluated the influence of these treatments on the mechanical properties of tendons. After a single freeze-thaw cycle, most cells isolated from frozen bone appeared morphologically as osteocytes and expressed both osteoblast- and osteocyte-related genes. Transmission electron microscopic observation of frozen cells using freeze-substitution revealed that a small number of osteocytes maintained large nuclei with intact double membranes, indicating that these osteocytes in bone matrix were resistant to ice crystal formation. We found that tendon cells were completely killed by a single freeze-thaw cycle, whereas bone cells exhibited a relatively high survival rate, although survival was significantly reduced after three freeze-thaw cycles. In patella tendons, the ultimate stress, Young's modulus, and strain at failure showed no significant differences between untreated tendons and those subjected to five freeze-thaw cycles. In conclusion, we identified that cells surviving after freeze-thaw treatment of rat bones were predominantly osteocytes. We propose that repeated freeze-thaw cycles could be applied for processing bone-tendon constructs prior to grafting as the treatment did not affect the mechanical property of tendons and drastically reduced surviving osteocytes, thereby potentially decreasing allograft immunogenecity.

  17. To freeze or not to freeze embryos: clarity, confusion and conflict.

    Science.gov (United States)

    Goswami, Mohar; Murdoch, Alison P; Haimes, Erica

    2015-06-01

    Although embryo freezing is a routine clinical practice, there is little contemporary evidence on how couples make the decision to freeze their surplus embryos, or of their perceptions during that time. This article describes a qualitative study of 16 couples who have had in vitro fertilisation (IVF) treatment. The study question was 'What are the personal and social factors that patients consider when deciding whether to freeze embryos?' We show that while the desire for a baby is the dominant drive, couples' views revealed more nuanced and complex considerations in the decision-making process. It was clear that the desire to have a baby influenced couples' decision-making and that they saw freezing as 'part of the process'. However, there were confusions associated with the term 'freezing' related to concerns about the safety of the procedure. Despite being given written information, couples were confused about the practical aspects of embryo freezing, which suggests they were preoccupied with the immediate demands of IVF. Couples expressed ethical conflicts about freezing 'babies'. We hope the findings from this study will inform clinicians and assist them in providing support to couples confronted with this difficult decision-making.

  18. Bone substitute biomaterials

    CERN Document Server

    Mallick, K

    2014-01-01

    Bone substitute biomaterials are fundamental to the biomedical sector, and have recently benefitted from extensive research and technological advances aimed at minimizing failure rates and reducing the need for further surgery. This book reviews these developments, with a particular focus on the desirable properties for bone substitute materials and their potential to encourage bone repair and regeneration. Part I covers the principles of bone substitute biomaterials for medical applications. One chapter reviews the quantification of bone mechanics at the whole-bone, micro-scale, and non-scale levels, while others discuss biomineralization, osteoductivization, materials to fill bone defects, and bioresorbable materials. Part II focuses on biomaterials as scaffolds and implants, including multi-functional scaffolds, bioceramics, and titanium-based foams. Finally, Part III reviews further materials with the potential to encourage bone repair and regeneration, including cartilage grafts, chitosan, inorganic poly...

  19. [Delegation yes, substitution no!].

    Science.gov (United States)

    Schroeder, A

    2014-08-01

    The aging of society leads on the one hand to increasing case numbers and on the other hand to a reduction in the number of physicians available for patient treatment. The delegation and substitution of medical duties as a tried and tested method is increasingly being recommended in order to compensate for the lack of physicians. The Berufsverband der Deutschen Urologen (BDU, Professional Association of German Urologists) supports the guiding principle of the Bundesärztekammer (Federal Medical Council) of "delegation yes, substitution no" and rejects a substitution of medical duties by non-medical academic health personnel. Against the background of the demographic changes, the increasing need for treatment and the current deficiency of junior physicians, a more extensive inclusion of well-qualified and experienced non-medical personnel by the delegation of medically responsible duties (medical scope of practice) can be an appropriate measure to maintain a good medical service in practices, hospitals and nursing homes.

  20. Aryl substitution of pentacenes

    Directory of Open Access Journals (Sweden)

    Andreas R. Waterloo

    2014-07-01

    Full Text Available A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films, thermoanalytical methods (DSC and TGA, cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives. X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices.

  1. Aryl substitution of pentacenes

    Science.gov (United States)

    Waterloo, Andreas R; Sale, Anna-Chiara; Lehnherr, Dan; Hampel, Frank

    2014-01-01

    Summary A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films), thermoanalytical methods (DSC and TGA), cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives). X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices. PMID:25161729

  2. Muon substituted free radicals

    International Nuclear Information System (INIS)

    Burkhard, P.; Fischer, H.; Roduner, E.; Strub, W.; Gygax, F.N.; Brinkman, G.A.; Louwrier, P.W.F.; McKenna, D.; Ramos, M.; Webster, B.C.

    1984-01-01

    Spin polarized energetic positive muons are injected as magnetic probes into unsaturated organic liquids. They are implemented via fast chemical processes ( -10 s) in various molecules. Of particular interest among these are muonium substituted free radicals. The technique allows determination of accurate rate coefficients for fast chemical reactions of radicals. Furthermore, radiochemical processes occuring in picoseconds after injection of the muon are studied. Of fundamental interest are also the structural and dynamical implications of substituting a proton by a muon, or in other terms, a hydrogen atom by a muonium atom. Selected examples for each of these three types of experiments are given. (Auth.)

  3. Aversive Life Events Enhance Human Freezing Responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  4. Aversive life events enhance human freezing responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  5. The Practicalities of Assessing Freezing of Gait

    NARCIS (Netherlands)

    Barthel, C.; Mallia, E.; Debu, B.; Bloem, B.R.; Ferraye, M.U.

    2016-01-01

    BACKGROUND: Freezing of gait (FOG) is a mysterious, complex and debilitating phenomenon in Parkinson's disease. Adequate assessment is a pre-requisite for managing FOG, as well as for assigning participants in FOG research. The episodic nature of FOG, as well as its multiple clinical expressions

  6. Freezing of Water Droplet due to Evaporation

    Science.gov (United States)

    Satoh, Isao; Fushinobu, Kazuyoshi; Hashimoto, Yu

    In this study, the feasibility of cooling/freezing of phase change.. materials(PCMs) due to evaporation for cold storage systems was experimentally examined. A pure water was used as the test PCM, since the latent heat due to evaporation of water is about 7 times larger than that due to freezing. A water droplet, the diameter of which was 1-4 mm, was suspended in a test cell by a fine metal wire (O. D.= 100μm),and the cell was suddenly evacuated up to the pressure lower than the triple-point pressure of water, so as to enhance the evaporation from the water surface. Temperature of the droplet was measured by a thermocouple, and the cooling/freezing behavior and the temperature profile of the droplet surface were captured by using a video camera and an IR thermo-camera, respectively. The obtained results showed that the water droplet in the evacuated cell is effectively cooled by the evaporation of water itself, and is frozen within a few seconds through remarkable supercooling state. When the initial temperature of the droplet is slightly higher than the room temperature, boiling phenomena occur in the droplet simultaneously with the freezing due to evaporation. Under such conditions, it was shown that the degree of supercooling of the droplet is reduced by the bubbles generated in the droplet.

  7. Rehydration kinetics of freeze-dried carrots

    NARCIS (Netherlands)

    Vergeldt, F.J.; Dalen, van G.; Duijster, A.J.; Voda, A.; Khalloufi, S.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.; Sman, van der R.G.M.

    2014-01-01

    Rehydration kinetics by two modes of imbibition is studied in pieces of freeze-dried winter carrot, after different thermal pre-treatments. Water ingress at room temperature is measured in real time by in situ MRI and NMR relaxometry. Blanched samples rehydrate substantially faster compared to

  8. Sysnthesis of powders by freeze-drying

    International Nuclear Information System (INIS)

    Johnson, S.M.; Gusman, M.I.; Hildenbrand, D.L.

    1988-01-01

    The freeze-drying method of synthesizing powders of the superconducting oxide YBa 2 Cu 3 O 7 - δ is described. This process produces homogeneous, submicron powders of high purity. The effects of salt selection, solution concentration and pH on the process are described. Some evaluation of the sintering behavior and the effects on critical current density are included

  9. Freeze block testing of buried waste lines

    International Nuclear Information System (INIS)

    Robbins, E.D.; Willi, J.C.

    1976-01-01

    An investigation was conducted to demonstrate application of freeze blocking in waste transfer lines such that a hydrostatic pressure test can be applied. A shop test was conducted on a 20-foot length, 3-inch schedule 40, carbon steel pipe using a coolant of dry ice and Freon. The positive results from these tests prompted a similar employment of the freeze block method in hydrostatic pressure testing the feed inlet leading to 241-S-101 Waste Tank. This pipeline is a 3-inch schedule 10, stainless steel pipe approximately 800 feet long. The freeze block was formed near the lower end of the pipe as it entered the 101-S Waste Tank and a pressure hold test was applied to this pipeline. This test proved the integrity of the pipeline in question, and demonstrated the validity of freeze blocking an open-ended pipeline which could not be hydrotested in other conventional ways. The field demonstration facility, costing $30,200 was completed late in 1975

  10. Scaling-Up Eutectic Freeze Crystallization

    NARCIS (Netherlands)

    Genceli, F.E.

    2008-01-01

    A novel crystallization technology, Eutectic Freeze Crystallization (EFC) has been investigated and further developed in this thesis work. EFC operates around the eutectic temperature and composition of aqueous solutions and can be used for recovery of (valuable) dissolved salts (and/or or acids)

  11. Static delectric behavior of charged fluids near freezing

    International Nuclear Information System (INIS)

    Fasolino, A.; Parrinello, M.; Tosi, M.P.

    1978-01-01

    The wavenumber-dependent, static dielectric function of classical charged fluids near freezing is obtained from structural data based on computer simulation or neutron diffraction, and its behavior is connected with the freezing process. (Auth.)

  12. Canalization of freeze tolerance in an alpine grasshopper.

    Science.gov (United States)

    Hawes, Timothy C

    2015-10-01

    In the Rock and Pillar Range, New Zealand, the alpine grasshopper, Sigaus australis Hutton, survives equilibrium freezing (EF) all-year round. A comparison of freeze tolerance (FT) in grasshoppers over four austral seasons for a 1 year period finds that: (a) the majority (>70%) of the sample population of grasshoppers survive single freeze-stress throughout the year; (b) exposure to increased freeze stress (multiple freeze-stress events) does not lead to a loss of freeze tolerance; and (c) responses to increased freeze stress reveal seasonal tuning of the FT adaptation to environmental temperatures. The Rock and Pillar sample population provides a clear example of the canalization of the FT adaptation. Seasonal variability in the extent of tolerance of multiple freezing events indicates that physiology is modulated to environmental temperatures by phenotypic plasticity - i.e. the FT adaptation is permanent and adjustable. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Adaptive Control of Freeze-Form Extrusion Fabrication Processes (Preprint)

    National Research Council Canada - National Science Library

    Zhao, Xiyue; Landers, Robert G; Leu, Ming C

    2008-01-01

    Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing process that extrudes high solids loading aqueous ceramic pastes in a layer-by-layer fashion below the paste freezing temperature for component fabrication...

  14. Freeze-thaw performance testing of whole concrete railroad ties.

    Science.gov (United States)

    2013-10-01

    Freezing and thawing durability tests of prestressed concrete ties are normally performed according to ASTM C666 specifications. Small specimens are cut from the shoulders of concrete ties and tested through 300 cycles of freezing and thawing. Saw-cu...

  15. Freezing temperature protection admixture for Portland cement concrete

    Science.gov (United States)

    1996-10-01

    A number of experimental admixtures were compared to Pozzutec 20 admixture for their ability to protect fresh concrete from freezing and for increasing the rate of cement hydration at below-freezing temperatures. The commercial accelerator and low-te...

  16. Water vapor movement in freezing aggregate base materials.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

  17. Hazardous solvent substitution

    International Nuclear Information System (INIS)

    Twitchell, K.E.

    1995-01-01

    This article is an overview of efforts at INEL to reduce the generation of hazardous wastes through the elimination of hazardous solvents. To aid in their efforts, a number of databases have been developed and will become a part of an Integrated Solvent Substitution Data System. This latter data system will be accessible through Internet

  18. Carbolanthanation of substituted alkynes

    International Nuclear Information System (INIS)

    Kalinin, V.N.; Kazimirchuk, E.I.; Vitt, S.V.; Khandozhko, V.N.; Beletskaya, I.P.

    1993-01-01

    Using the reaction between CH 3 YbI and substituted alkynes as an example, agents can enter into carbolanthanation reaction via transfer of a methyl group to carbon atom of acetylene bond with the production of a new olefin carbanion. 5 refs.; 1 fig.; 3 tabs

  19. Faktor Influencing the Vacuum Freezing Rate of Liquid Food

    OpenAIRE

    Tambunan, Armansyah H

    2000-01-01

    Many,freezing methods, mechanicul as well as cryogenic, have been in wide application in food industries. Each method has its own advantage, but in regard with the food quality, freezing rule can be accomplished by the method is one of the tnost important factors. Nowadays, many researchers are conducting experiment in order to enhance thefi.eezing rate. This paper deals with the advantage of vacuum freezing method in enhancing the freezing rate and its applicability for liquidfood.Experinren...

  20. Objective video quality assessment method for freeze distortion based on freeze aggregation

    Science.gov (United States)

    Watanabe, Keishiro; Okamoto, Jun; Kurita, Takaaki

    2006-01-01

    With the development of the broadband network, video communications such as videophone, video distribution, and IPTV services are beginning to become common. In order to provide these services appropriately, we must manage them based on subjective video quality, in addition to designing a network system based on it. Currently, subjective quality assessment is the main method used to quantify video quality. However, it is time-consuming and expensive. Therefore, we need an objective quality assessment technology that can estimate video quality from video characteristics effectively. Video degradation can be categorized into two types: spatial and temporal. Objective quality assessment methods for spatial degradation have been studied extensively, but methods for temporal degradation have hardly been examined even though it occurs frequently due to network degradation and has a large impact on subjective quality. In this paper, we propose an objective quality assessment method for temporal degradation. Our approach is to aggregate multiple freeze distortions into an equivalent freeze distortion and then derive the objective video quality from the equivalent freeze distortion. Specifically, our method considers the total length of all freeze distortions in a video sequence as the length of the equivalent single freeze distortion. In addition, we propose a method using the perceptual characteristics of short freeze distortions. We verified that our method can estimate the objective video quality well within the deviation of subjective video quality.

  1. SLAPex Freeze/Thaw 2015: The First Dedicated Soil Freeze/Thaw Airborne Campaign

    Science.gov (United States)

    Kim, Edward; Wu, Albert; DeMarco, Eugenia; Powers, Jarrett; Berg, Aaron; Rowlandson, Tracy; Freeman, Jacqueline; Gottfried, Kurt; Toose, Peter; Roy, Alexandre; hide

    2016-01-01

    Soil freezing and thawing is an important process in the terrestrial water, energy, and carbon cycles, marking the change between two very different hydraulic, thermal, and biological regimes. NASA's Soil Moisture Active/Passive (SMAP) mission includes a binary freeze/thaw data product. While there have been ground-based remote sensing field measurements observing soil freeze/thaw at the point scale, and airborne campaigns that observed some frozen soil areas (e.g., BOREAS), the recently-completed SLAPex Freeze/Thaw (F/T) campaign is the first airborne campaign dedicated solely to observing frozen/thawed soil with both passive and active microwave sensors and dedicated ground truth, in order to enable detailed process-level exploration of the remote sensing signatures and in situ soil conditions. SLAPex F/T utilized the Scanning L-band Active/Passive (SLAP) instrument, an airborne simulator of SMAP developed at NASA's Goddard Space Flight Center, and was conducted near Winnipeg, Manitoba, Canada, in October/November, 2015. Future soil moisture missions are also expected to include soil freeze/thaw products, and the loss of the radar on SMAP means that airborne radar-radiometer observations like those that SLAP provides are unique assets for freeze/thaw algorithm development. This paper will present an overview of SLAPex F/T, including descriptions of the site, airborne and ground-based remote sensing, ground truth, as well as preliminary results.

  2. 7 CFR 58.620 - Freezing and packaging rooms.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Freezing and packaging rooms. 58.620 Section 58.620 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  3. Applications of Simulator Freeze to Carrier Glideslope Tracking Instruction.

    Science.gov (United States)

    1982-07-01

    Showing Datum Bars and Meatball . .. .. .. ... .. ... .... 19 4 Freezes Per Trial Averaged Across Freeze Conditions and Across 4-Trial Blocks of Training...algorithm linearly increased the criterion in meatball units from 1.0 at 6000 feet from the ramp to 1.5 at the ramp. "Freezes" did not occur beyond 6000

  4. The freezing and supercooling of garlic (Allium sativum L.)

    Energy Technology Data Exchange (ETDEWEB)

    James, Christian; Seignemartin, Violaine; James, Stephen J. [Food Refrigeration and Process Engineering Research Centre (FRPERC), University of Bristol, Churchill Building, Langford, Bristol BS40 5DU (United Kingdom)

    2009-03-15

    This work shows that peeled garlic cloves demonstrate significant supercooling during freezing under standard conditions and can be stored at temperatures well below their freezing point (-2.7 C) without freezing. The nucleation point or 'metastable limit temperature' (the point at which ice crystal nucleation is initiated) of peeled garlic cloves was found to be between -7.7 and -14.6 C. Peeled garlic cloves were stored under static air conditions at temperatures between -6 and -9 C for up to 69 h without freezing, and unpeeled whole garlic bulbs and cloves were stored for 1 week at -6 C without freezing. (author)

  5. [Currently available skin substitutes].

    Science.gov (United States)

    Oravcová, Darina; Koller, Ján

    2014-01-01

    The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. Autologous split or full-thickness skin graft are the best definitive burn wound coverage, but it is constrained by the limited available sources, especially in major burns. Donor site morbidities in term of additional wounds and scarring are also of concern of the autograft application. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. This paper reviews currently available skin substitutes, produced in not for-profit skin banks as well as commercially available. They are divided according to type of material included, as biological, biosynthetic and synthetic and named respectively.

  6. SOME STUDIES ON FREEZE - DRIED ARTERIES

    Directory of Open Access Journals (Sweden)

    H. Sadeghi - Nejad

    1970-01-01

    Full Text Available (1 The secondary stage of freeze - drying, particularly the last day, is not important and I suggest the whole procedure is reduced to three days, the primary stage occupying two of these. (2 The mothod used obtains the satisfactory low level of residual moisture. RESUME (3 Experiments on reconstitution with saline and distilled water show that distilled water is more satisfactory and I suggest that saline should not he used.

  7. Atmospheric freeze drying assisted by power ultrasound

    International Nuclear Information System (INIS)

    Santacatalina, J V; Cárcel, J A; Garcia-Perez, J V; Mulet, A; Simal, S

    2012-01-01

    Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that purpose, AFD experiments were carried out with carrot cubes (10 mm side) at constant air velocity (2 ms −1 ), temperature (−10°C) and relative humidity (10%) with (20.5 kWm −3 ,USAFD) and without (AFD) ultrasonic application. A diffusion model was used in order to quantify the influence of US in drying kinetics. To evaluate the quality of dry products, rehydration capacity and textural properties were determined. The US application during AFD of carrot involved the increase of drying rate. The effective moisture diffusivity identified in USAFD was 73% higher than in AFD experiments. On the other hand, the rehydration capacity was higher in USAFD than in AFD and the hardness of dried samples did not show significant (p<0.05) differences. Therefore, US application during AFD significantly (p<0.05) sped-up the drying process preserving the quality properties of the dry product.

  8. The influence of freezing rates on bovine pericardium tissue Freeze-drying

    Directory of Open Access Journals (Sweden)

    Camila Figueiredo Borgognoni

    2009-12-01

    Full Text Available The bovine pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a bovine pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the bovine pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.O pericárdio bovino é um material utilizado na fabricação de biopróteses. A liofilização é um método de secagem que vem sendo estudado para a conservação de válvulas cardíacas. A preservação das características do biomaterial é de fundamental importância no bom funcionamento das válvulas. Este artigo é a primeira etapa do desenvolvimento do ciclo de liofilização do pericárdio bovino. Liofilização é o processo de secagem no qual a água é removida do material congelado por sublimação e desorção da água incongelável, sob pressão reduzida. O congelamento influencia o tamanho do cristal de gelo e, consequentemente, a secagem primária e secundária. O objetivo deste estudo foi verificar a influência das taxas de congelamento nos parâmetros de liofilização do pericárdio bovino. Determinou-se a temperatura de transição vítrea e o comportamento estrutural do pericárdio bovino liofilizado. Determinou-se o tempo da secagem primária e secundária. O

  9. Food deprivation and nicotine correct akinesia and freezing in Na(+) -leak current channel (NALCN)-deficient strains of Caenorhabditis elegans.

    Science.gov (United States)

    Bonnett, K; Zweig, R; Aamodt, E J; Dwyer, D S

    2014-09-01

    Mutations in various genes adversely affect locomotion in model organisms, and thus provide valuable clues about the complex processes that control movement. In Caenorhabditis elegans, loss-of-function mutations in the Na(+) leak current channel (NALCN) and associated proteins (UNC-79 and UNC-80) cause akinesia and fainting (abrupt freezing of movement during escape from touch). It is not known how defects in the NALCN induce these phenotypes or if they are chronic and irreversible. Here, we report that akinesia and freezing are state-dependent and reversible in NALCN-deficient mutants (nca-1;nca-2, unc-79 and unc-80) when additional cation channels substitute for this protein. Two main measures of locomotion were evaluated: spontaneous movement (traversal of >2 head lengths during a 5 second observation period) and the touch-freeze response (movement greater than three body bends in response to tail touch). Food deprivation for as little as 3 min stimulated spontaneous movement and corrected the touch-freeze response. Conversely, food-deprived animals that moved normally in the absence of bacteria rapidly reverted to uncoordinated movement when re-exposed to food. The effects of food deprivation were mimicked by nicotine, which suggested that acetylcholine mediated the response. Nicotine appeared to act on interneurons or motor neurons rather than directly at the neuromuscular junction because levamisole, which stimulates muscle contraction, did not correct movement. Neural circuits have been proposed to account for the effects of food deprivation and nicotine on spontaneous movement and freezing. The NALCN may play an unrecognized role in human movement disorders characterized by akinesia and freezing gait. © 2014 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  10. Recent developments in smart freezing technology applied to fresh foods.

    Science.gov (United States)

    Xu, Ji-Cheng; Zhang, Min; Mujumdar, Arun S; Adhikari, Benu

    2017-09-02

    Due to the increased awareness of consumers in sensorial and nutritional quality of frozen foods, the freezing technology has to seek new and innovative technologies for better retaining the fresh like quality of foods. In this article, we review the recent developments in smart freezing technology applied to fresh foods. The application of these intelligent technologies and the associated underpinning concepts have greatly improved the quality of frozen foods and the freezing efficiency. These technologies are able to automatically collect the information in-line during freezing and help control the freezing process better. Smart freezing technology includes new and intelligent technologies and concepts applied to the pretreatment of the frozen product, freezing processes, cold chain logistics as well as warehouse management. These technologies enable real-time monitoring of quality during the freezing process and help improve product quality and freezing efficiency. We also provide a brief overview of several sensing technologies used to achieve automatic control of individual steps of freezing process. These sensing technologies include computer vision, electronic nose, electronic tongue, digital simulation, confocal laser, near infrared spectroscopy, nuclear magnetic resonance technology and ultrasound. Understanding of the mechanism of these new technologies will be helpful for applying them to improve the quality of frozen foods.

  11. Hexavalent Chromium Substitution Projects

    Science.gov (United States)

    2011-05-12

    Hexavalent Chromium Substitution Projects Date (12 May 2011) Gene McKinley ASC/WNV (937) 255-3596 Gene.McKinley@wpafb.af.mil Aeronautical Systems...valid OMB control number. 1. REPORT DATE 12 MAY 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Hexavalent ...A-10) – AETC (T-6, T-38 and T1A) • Both Cr Primers & Non-Cr primers as well as Cr Surface Treatment – F-22 8 Non- Chrome Tie-coat & touch-up

  12. Muonium substituted molecules

    International Nuclear Information System (INIS)

    Cox, S.F.J.

    1990-12-01

    The manner in which Muon Spin Rotation and Level Crossing Resonance are used to characterise muonium substituted organic radicals is described, and illustrated with spectra for the ethyl radical and related species. Comparison with electron spin resonance data for the unsubstituted radicals reveals significant structural and hyperfine isotope effects which can be traced to the effects of zero point motion. The first comparable results for a diamagnetic species, exhibiting a quadrupole isotope effect by comparison with conventional nuclear quadrupole resonance data, are presented and discussed. (author)

  13. Comparing contact and immersion freezing from continuous flow diffusion chambers

    Directory of Open Access Journals (Sweden)

    B. Nagare

    2016-07-01

    Full Text Available Ice nucleating particles (INPs in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations  <  5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with immersion freezing or adhesion freezing. With “adhesion freezing”, we refer to a contact nucleation

  14. Resources, recycle, and substitution

    International Nuclear Information System (INIS)

    Wymer, R.G.

    A two-fold strategy appears necessary to ensure that the resource needs of the developed and developing nations are met. First, recycle and substitution must be encouraged in those instances where they do find application. Although these measures have limited applicability, they may be of vital importance in those instances where they do apply; in any event, they buy time. Second, practical and economical technologies must be developed to exploit the lower-grade and marginal ores and the oftentimes abundant but highly refractory ores, as well as to greatly increase the recovery of secondary elements present in the ores - elements whose form and amounts in the ores make them economically unrecoverable by themselves, but which are economically recoverable as by-products. It is often the case that if these elements are not recovered during the initial mining and milling operations, they are rendered unrecoverable, in a practical sense, forever. Furthermore, they may even become environmental pollutants. Specific examples of recovery from refractory ores, by-product recovery, and recycle are given. Also, some suggestions of substitutes for important resources are tabulated

  15. Freeze Casting for Assembling Bioinspired Structural Materials.

    Science.gov (United States)

    Cheng, Qunfeng; Huang, Chuanjin; Tomsia, Antoni P

    2017-12-01

    Nature is very successful in designing strong and tough, lightweight materials. Examples include seashells, bone, teeth, fish scales, wood, bamboo, silk, and many others. A distinctive feature of all these materials is that their properties are far superior to those of their constituent phases. Many of these natural materials are lamellar or layered in nature. With its "brick and mortar" structure, nacre is an example of a layered material that exhibits extraordinary physical properties. Finding inspiration in living organisms to create bioinspired materials is the subject of intensive research. Several processing techniques have been proposed to design materials mimicking natural materials, such as layer-by-layer deposition, self-assembly, electrophoretic deposition, hydrogel casting, doctor blading, and many others. Freeze casting, also known as ice-templating, is a technique that has received considerable attention in recent years to produce bioinspired bulk materials. Here, recent advances in the freeze-casting technique are reviewed for fabricating lamellar scaffolds by assembling different dimensional building blocks, including nanoparticles, polymer chains, nanofibers, and nanosheets. These lamellar scaffolds are often infiltrated by a second phase, typically a soft polymer matrix, a hard ceramic matrix, or a metal matrix. The unique architecture of the resultant bioinspired structural materials displays excellent mechanical properties. The challenges of the current research in using the freeze-casting technique to create materials large enough to be useful are also discussed, and the technique's promise for fabricating high-performance nacre-inspired structural materials in the future is reviewed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Freeze-Dehydration by Microwave Energy

    Science.gov (United States)

    1974-12-01

    ntration and ter perat ure pr ofi l es for the microwave freeze-drying proce~s. .... c Q) () c 0 (.) )( CD 1.0 0 th e ver t ex of the parabola ...is chosen because a plot of kF vs temperature resembles a parabola with axis parallel to the horizontal temperature axis, and tangent at the vertex...validity of utili z ing the dielectric data of the alcohol ques tionable. However, this system is used as an indicator of melting occurence in the

  17. Freeze-fracture study of Trichomonas vaginalis

    Directory of Open Access Journals (Sweden)

    Marlene Benchimol

    1990-12-01

    Full Text Available The freeze-fracture technique was used to analyse the organization of the plasma membrane, as well as membranes of cytoplasmic organelles, of the pathogenic protozoan Trichomonas vaginalis. Rosettes formed by 4 to 14 intramembranous particles were seen on the fracture faces of the membrane lining the anterior flagella as well as in fracture faces of the plasma membrane enclosing the anterior region of the protozoan and in cytoplasmic organelles. Special organization of the membrane particles were also seen in the region of association of the recurrent flagellum to the cell body.

  18. Gradient porous hydroxyapatite ceramics fabricated by freeze casting method

    International Nuclear Information System (INIS)

    Zuo Kaihui; Zhang Yuan; Jiang Dongliang; Zeng Yuping

    2011-01-01

    By controlling the cooling rates and the composition of slurries, the gradient porous hydroxyapatite ceramics are fabricated by the freeze casting method. According to the different cooling rate, the pores of HAP ceramics fabricated by gradient freeze casting are divided into three parts: one is lamellar pores, another is column pore and the last one is fine round pores. The laminated freeze casting is in favour of obtaining the gradient porous ceramics composed of different materials and the ceramics have unclear interfaces.

  19. Air-cooled steam condensers non-freeze warranties

    Energy Technology Data Exchange (ETDEWEB)

    Larinoff, M.W.

    1995-09-01

    What this paper is suggesting is the seller quote a condenser package with a LIMITED NON-FREEZE WARRANTY. Relieve the inexperienced buyer of the responsibility for selecting freeze protection design options. The seller cannot afford to over-design because of the added costs and the need for a competitive price. Yet he cannot under-design and allow the condenser tubes to freeze periodically and then pay the repair bills in accordance with the warranty.

  20. Effects of various freezing containers for vitrification freezing on mouse oogenesis.

    Science.gov (United States)

    Kim, Ji Chul; Kim, Jae Myeoung; Seo, Byoung Boo

    2016-01-01

    In the present study, various freezing containers were tested for mouse embryos of respective developmental stages; embryos were vitrified and then their survival rate and developmental rate were monitored. Mouse two cell, 8 cell, and blastula stage embryos underwent vitrification freezing-thawing and then their recovery rate, survival rate, development rate, and hatching rate were investigated. EM-grid, OPS, and cryo-loop were utilized for vitrification freezing-thawing of mouse embryos. It was found that recovery rate and survival rate were higher in the group of cryo-loop compared to those of EM-grid (p containers on vitrified embryos of respective developmental stages; it was demonstrated that higher developmental rate was shown in more progressed (or developed) embryos with more blastomeres. There was however, no difference in embryonic development rate was shown amongst containers. Taken together, further additional studies are warranted with regards to 1) manipulation techniques of embryos for various vitrification freezing containers and 2) preventive measures against contamination via liquid nitrogen.

  1. Parameter Sensitivity of the Microdroplet Vacuum Freezing Process

    Directory of Open Access Journals (Sweden)

    Zhijun Zhang

    2015-01-01

    Full Text Available The vacuum freezing process of microdroplets (1 mm. Pressure and droplet diameter have an effect on cooling and freezing stages, but initial temperature only affects the cooling stage. The thermal conductivity coefficient kl affected the cooling stage, whereas ki affected the freezing stage. Heat capacity Cl affected the cooling stage, but Ci has virtually no effect on all stages. The actual latent heat of freezing ΔH was also affected. Higher density corresponds to lower cooling rate in the cooling stage.

  2. Effects of freezing conditions on quality changes in blueberries.

    Science.gov (United States)

    Cao, Xuehui; Zhang, Fangfang; Zhao, Dongyu; Zhu, Danshi; Li, Jianrong

    2018-03-12

    Freezing preservation is one of the most effective methods used to maintain the flavour and nutritional value of fruit. This research studied the effects of different freezing conditions, -20 °C, -40 °C, -80 °C, and immersion in liquid nitrogen, on quality changes of freeze-thawed blueberries. The water distribution estimates of blueberries were measured based on low-field nuclear magnetic resonance (LF-NMR) analysis. The pectin content, drip loss, and fruit texture were also detected to evaluate quality changes in samples. The freezing curves of blueberry showed super-cooling points at -20 °C and - 40 °C, whereas super-cooling points were not observed at -80 °C or in liquid nitrogen. After freeze-thaw treatment, the relaxation time of the cell wall water (T 21 ), cytoplasm water and extracellular space (T 22 ), and vacuole water (T 23 ) were significantly shortened compared to fresh samples, which suggested a lower liquidity. Although the freezing speed for samples immersed in liquid nitrogen was faster than other treatments, samples treated at -80 °C showed better quality regarding vacuole water holding, drip loss, and original pectin content retention. This study contributed to understanding how freezing temperature affects the qualities of blueberries. The super-fast freezing rate might injure fruit, and an appropriate freezing rate could better preserve blueberries. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  3. Cryopreservation of boar semen. III: Ultrastructure of boar spermatozoa frozen ultra-rapidly at various stages of conventional freezing and thawing.

    Science.gov (United States)

    Bwanga, C O; Ekwall, H; Rodriguez-Martinez, H

    1991-01-01

    Ejaculated boar spermatozoa subjected to a conventional freezing and thawing process, were ultra-rapidly fixed, freeze-substituted and examined by electron microscopy to monitor the presence of real or potential intracellular ice and the degree of cell protection attained with the different extenders used during the process. Numerous ice crystal marks representing the degree of hydration of the cells were located in the perinuclear space of those spermatozoa not in proper contact with the extender containing glycerol (i.e. prior to freezing). The spermatozoa which were in proper contact with the extenders presented a high degree of preservation of the acrosomes, plasma membranes as well as the nuclear envelopes. No ice marks were detected in acrosomes before thawing, indicating that the conventional assayed cryopreservation method provided a good protection against cryoinjury. The presence of acrosomal changes (internal vesiculization, hydration and swelling) in thawed samples however, raises serious questions about the thawing procedure employed.

  4. Rapid freezing of water under dynamic compression

    Science.gov (United States)

    Myint, Philip C.; Belof, Jonathan L.

    2018-06-01

    Understanding the behavior of materials at extreme pressures is a central issue in fields like aerodynamics, astronomy, and geology, as well as for advancing technological grand challenges such as inertial confinement fusion. Dynamic compression experiments to probe high-pressure states often encounter rapid phase transitions that may cause the materials to behave in unexpected ways, and understanding the kinetics of these phase transitions remains an area of great interest. In this review, we examine experimental and theoretical/computational efforts to study the freezing kinetics of water to a high-pressure solid phase known as ice VII. We first present a detailed analysis of dynamic compression experiments in which water has been observed to freeze on sub-microsecond time scales to ice VII. This is followed by a discussion of the limitations of currently available molecular and continuum simulation methods in modeling these experiments. We then describe how our phase transition kinetics models, which are based on classical nucleation theory, provide a more physics-based framework that overcomes some of these limitations. Finally, we give suggestions on future experimental and modeling work on the liquid–ice VII transition, including an outline of the development of a predictive multiscale model in which molecular and continuum simulations are intimately coupled.

  5. Application of the Quality by Design Approach to the Freezing Step of Freeze-Drying: Building the Design Space.

    Science.gov (United States)

    Arsiccio, Andrea; Pisano, Roberto

    2018-06-01

    The present work shows a rational method for the development of the freezing step of a freeze-drying cycle. The current approach to the selection of freezing conditions is still empirical and nonsystematic, thus resulting in poor robustness of control strategy. The final aim of this work is to fill this gap, describing a rational procedure, based on mathematical modeling, for properly choosing the freezing conditions. Mechanistic models are used for the prediction of temperature profiles during freezing and dimension of ice crystals being formed. Mathematical description of the drying phase of freeze-drying is also coupled with the results obtained by freezing models, thus providing a comprehensive characterization of the lyophilization process. In this framework, deep understanding of the phenomena involved is required, and according to the Quality by Design approach, this knowledge can be used to build the design space. The step-by-step procedure for building the design space for freezing is thus described, and examples of applications are provided. The calculated design space is validated upon experimental data, and we show that it allows easy control of the freezing process and fast selection of appropriate operating conditions. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  6. Increased spring freezing vulnerability for alpine shrubs under early snowmelt.

    Science.gov (United States)

    Wheeler, J A; Hoch, G; Cortés, A J; Sedlacek, J; Wipf, S; Rixen, C

    2014-05-01

    Alpine dwarf shrub communities are phenologically linked with snowmelt timing, so early spring exposure may increase risk of freezing damage during early development, and consequently reduce seasonal growth. We examined whether environmental factors (duration of snow cover, elevation) influenced size and the vulnerability of shrubs to spring freezing along elevational gradients and snow microhabitats by modelling the past frequency of spring freezing events. We sampled biomass and measured the size of Salix herbacea, Vaccinium myrtillus, Vaccinium uliginosum and Loiseleuria procumbens in late spring. Leaves were exposed to freezing temperatures to determine the temperature at which 50% of specimens are killed for each species and sampling site. By linking site snowmelt and temperatures to long-term climate measurements, we extrapolated the frequency of spring freezing events at each elevation, snow microhabitat and per species over 37 years. Snowmelt timing was significantly driven by microhabitat effects, but was independent of elevation. Shrub growth was neither enhanced nor reduced by earlier snowmelt, but decreased with elevation. Freezing resistance was strongly species dependent, and did not differ along the elevation or snowmelt gradient. Microclimate extrapolation suggested that potentially lethal freezing events (in May and June) occurred for three of the four species examined. Freezing events never occurred on late snow beds, and increased in frequency with earlier snowmelt and higher elevation. Extrapolated freezing events showed a slight, non-significant increase over the 37-year record. We suggest that earlier snowmelt does not enhance growth in four dominant alpine shrubs, but increases the risk of lethal spring freezing exposure for less freezing-resistant species.

  7. Currency substitution in Eastern Europe

    NARCIS (Netherlands)

    van Aarle, B.; Budina, N.

    1995-01-01

    Monetary instability during the transition process from a command economy to a market economy has induced a considerable increase in currency substitution in Eastern Europe. Currency substitution itself affects monetary stability since it reduces the stability of velocity. This paper investigates

  8. Why Does Trigonometric Substitution Work?

    Science.gov (United States)

    Cunningham, Daniel W.

    2018-01-01

    Modern calculus textbooks carefully illustrate how to perform integration by trigonometric substitution. Unfortunately, most of these books do not adequately justify this powerful technique of integration. In this article, we present an accessible proof that establishes the validity of integration by trigonometric substitution. The proof offers…

  9. Substitution of matrices over rings

    NARCIS (Netherlands)

    Hautus, M.L.J.

    1995-01-01

    For a given commutative ring with an identity element, we define and study the substitution of a matrix with entries in into a matrix polynomial or rational function over . A Bezout-type remainder theorem and a "partial-substitution rule" are derived and used to obtain a number of results. The

  10. Substitution in recreation choice behavior

    Science.gov (United States)

    George L. Peterson; Daniel J. Stynes; Donald H. Rosenthal; John F. Dwyer

    1985-01-01

    This review discusses concepts and theories of substitution in recreation choice. It brings together the literature of recreation research, psychology, geography, economics, and transportation. Parallel and complementary developments need integration into an improved theory of substitution. Recreation decision behavior is characterized as a nested or sequential choice...

  11. Biological background of dermal substitutes

    NARCIS (Netherlands)

    van der Veen, V. C.; van der Wal, M.B.; van Leeuwen, M.C.; Ulrich, M.; Middelkoop, E.

    2010-01-01

    Dermal substitutes are of major importance in treating full thickness skin defects, both in acute and chronic wounds. In this review we will outline specific requirements of three classes of dermal substitutes:-natural biological materials, with a more or less intact extracellular matrix

  12. Do freeze events create a demographic bottleneck for Colophospermum mopane?

    CSIR Research Space (South Africa)

    Whitecross, MA

    2012-11-01

    Full Text Available capacity of the effected plants. A severely freeze-damaged stand of Colophospermum mopane along a slope in the Venetia Limpopo Nature Reserve provided an opportunity to investigate the nature of freeze-damage impacts on C. mopane. Is this disturbance a...

  13. A subspecies of region crossing change, region freeze crossing change

    OpenAIRE

    Inoue, Ayumu; Shimizu, Ryo

    2016-01-01

    We introduce a local move on a link diagram named a region freeze crossing change which is close to a region crossing change, but not the same. We study similarity and difference between region crossing change and region freeze crossing change.

  14. Cellularized Cellular Solids via Freeze-Casting.

    Science.gov (United States)

    Christoph, Sarah; Kwiatoszynski, Julien; Coradin, Thibaud; Fernandes, Francisco M

    2016-02-01

    The elaboration of metabolically active cell-containing materials is a decisive step toward the successful application of cell based technologies. The present work unveils a new process allowing to simultaneously encapsulate living cells and shaping cell-containing materials into solid-state macroporous foams with precisely controlled morphology. Our strategy is based on freeze casting, an ice templating materials processing technique that has recently emerged for the structuration of colloids into macroporous materials. Our results indicate that it is possible to combine the precise structuration of the materials with cellular metabolic activity for the model organism Saccharomyces cerevisiae. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. STEFINS: a steel freezing integral simulation program

    International Nuclear Information System (INIS)

    Frank, M.V.

    1980-09-01

    STEFINS (STEel Freezing INtegral Simulation) is a computer program for the calculation of the rate of solidification of molten steel on solid steel. Such computations arize when investigating core melt accidents in fast reactors. In principle this problem involves a coupled two-dimensional thermal and hydraulic approach. However, by physically reasonable assumptions a decoupled approach has been developed. The transient solidification of molten steel on a cold wall is solved in the direction normal to the molten steel flow and independent from the solution for the molten steel temperature and Nusselt number along the direction of flow. The solutions to the applicable energy equations have been programmed in cylindrical and slab geometries. Internal gamma heating of steel is included

  16. Solar desalination by freezing and distillation

    Science.gov (United States)

    Kvajic, G.

    It is noted that among seawater desalination processes the absorption-freeze vapor compression processes based on the thermal heat pump, although untested commercially and still in the development stage, appears technically and economically an attractive application of low-grade (exergy) solar heat. The distillation processes proposed here may be conveniently powered by low-grade solar heat (from flat plate solar collectors). It is expected that the scaling problem will be insignificant in comparison with that encountered in the conventional multistage flash process. The novel feature here is the use of enlarged capacity for heat exchange between distillate and brine via latent heat of solid-liquid phase change of a suitable hydrophobic intermediate heat transfer material.

  17. Cooling method with automated seasonal freeze protection

    Science.gov (United States)

    Cambell, Levi; Chu, Richard; David, Milnes; Ellsworth, Jr, Michael; Iyengar, Madhusudan; Simons, Robert; Singh, Prabjit; Zhang, Jing

    2016-05-31

    An automated multi-fluid cooling method is provided for cooling an electronic component(s). The method includes obtaining a coolant loop, and providing a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

  18. Limonene encapsulation in freeze dried gellan systems.

    Science.gov (United States)

    Evageliou, Vasiliki; Saliari, Dimitra

    2017-05-15

    The encapsulation of limonene in freeze-dried gellan systems was investigated. Surface and encapsulated limonene content was determined by measurement of the absorbance at 252nm. Gellan matrices were both gels and solutions. For a standard gellan concentration (0.5wt%) gelation was induced by potassium or calcium chloride. Furthermore, gellan solutions of varying concentrations (0.25-1wt%) were also studied. Limonene was added at two different concentrations (1 and 2mL/100g sample). Gellan gels encapsulated greater amounts of limonene than solutions. Among all gellan gels, the KCl gels had the greater encapsulated limonene content. However, when the concentration of limonene was doubled in these KCl gels, the encapsulated limonene decreased. The surface limonene content was significant, especially for gellan solutions. The experimental conditions and not the mechanical properties of the matrices were the dominant factor in the interpretation of the observed results. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Cooling system with automated seasonal freeze protection

    Science.gov (United States)

    Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth, Jr., Michael J.; Iyengar, Madhusudan K.; Simons, Robert E.; Singh, Prabjit; Zhang, Jing

    2016-05-24

    An automated multi-fluid cooling system and method are provided for cooling an electronic component(s). The cooling system includes a coolant loop, a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

  20. Freezing Injury in Onion Bulb Cells

    Science.gov (United States)

    Palta, Jiwan P.; Levitt, Jacob; Stadelmann, Eduard J.

    1977-01-01

    Onion (Allium cepa L.) bulbs were frozen to −4 and −11 C and kept frozen for up to 12 days. After slow thawing, a 2.5-cm square from a bulb scale was transferred to 25 ml deionized H2O. After shaking for standard times, measurements were made on the effusate and on the effused cells. The results obtained were as follows. Even when the scale tissue was completely infiltrated, and when up to 85% of the ions had diffused out, all of the cells were still alive, as revealed by cytoplasmic streaming and ability to plasmolyze. The osmotic concentration of the cell sap, as measured plasmolytically, decreased in parallel to the rise in conductivity of the effusate. The K+ content of the effusate, plus its assumed counterion, accounted for only 20% of the total solutes, but for 100% of the conductivity. A large part of the nonelectrolytes in the remaining 80% of the solutes was sugars. The increased cell injury and infiltration in the −11 C treatment, relative to the −4 C and control (unfrozen) treatments, were paralleled by increases in conductivity, K+ content, sugar content, and pH of the effusate. In spite of the 100% infiltration of the tissue and the large increase in conductivity of the effusate following freezing, no increase in permeability of the cells to water could be detected. The above observations may indicate that freezing or thawing involves a disruption of the active transport system before the cells reveal any injury microscopically. PMID:16660100

  1. Predictive modeling of freezing and thawing of frost-susceptible soils.

    Science.gov (United States)

    2015-09-01

    Frost depth is an essential factor in design of various transportation infrastructures. In frost : susceptible soils, as soils freezes, water migrates through the soil voids below the freezing line : towards the freezing front and causes excessive he...

  2. Optimization of protectant, salinity and freezing condition for freeze-drying preservation of Edwardsiella tarda

    Science.gov (United States)

    Yu, Yongxiang; Zhang, Zheng; Wang, Yingeng; Liao, Meijie; Li, Bin; Xue, Liangyi

    2017-10-01

    Novel preservation condition without ultra-low temperature is needed for the study of pathogen in marine fishes. Freeze-drying is such a method usually used for preservation of terrigenous bacteria. However, studies using freeze-drying method to preserving marine microorganisms remain very limited. In this study, we optimized the composition of protectants during the freeze-drying of Edwardsiella tarda, a fish pathogen that causes systemic infection in marine fishes. We found that the optimal composition of protectant mixture contained trehalose (8.0%), skim milk (12.0%), sodium citrate (2.0%), serum (12.0%) and PVP (2.0%). Orthogonal and interaction analyses demonstrated the interaction between serum and skim milk or sodium citrate. The highest survival rate of E. tarda was observed when the concentration of NaCl was 10.0, 30.0 and between 5.0 and 10.0 g L-1 for preparing TSB medium, E. tarda suspension and protectant mixture, respectively. When E. tarda was frozen at -80°C or -40°C for 6 h, its survival rate was higher than that under other tested conditions. Under the optimized conditions, when the protectant mixture was used during freeze-drying process, the survival rate (79.63%-82.30%) of E. tarda was significantly higher than that obtained using single protectant. Scanning electron microscopy (SEM) image indicated that E. tarda was embedded in thick matrix with detectable aggregation. In sum, the protectant mixture may be used as a novel cryoprotective additive for E. tarda.

  3. Multiple Glass Transitions and Freezing Events of Aqueous Citric Acid

    Science.gov (United States)

    2014-01-01

    Calorimetric and optical cryo-microscope measurements of 10–64 wt % citric acid (CA) solutions subjected to moderate (3 K/min) and slow (0.5 and 0.1 K/min) cooling/warming rates and also to quenching/moderate warming between 320 and 133 K are presented. Depending on solution concentration and cooling rate, the obtained thermograms show one freezing event and from one to three liquid–glass transitions upon cooling and from one to six liquid–glass and reverse glass–liquid transitions, one or two freezing events, and one melting event upon warming of frozen/glassy CA/H2O. The multiple freezing events and glass transitions pertain to the mother CA/H2O solution itself and two freeze-concentrated solution regions, FCS1 and FCS2, of different concentrations. The FCS1 and FCS2 (or FCS22) are formed during the freezing of CA/H2O upon cooling and/or during the freezing upon warming of partly glassy or entirely glassy mother CA/H2O. The formation of two FCS1 and FCS22 regions during the freezing upon warming to our best knowledge has never been reported before. Using an optical cryo-microscope, we are able to observe the formation of a continuous ice framework (IF) and its morphology and reciprocal distribution of IF/(FCS1 + FCS2). Our results provide a new look at the freezing and glass transition behavior of aqueous solutions and can be used for the optimization of lyophilization and freezing of foods and biopharmaceutical formulations, among many other applications where freezing plays a crucial role. PMID:25482069

  4. The choice of a suitable oligosaccharide to prevent aggregation of PEGylated nanoparticles during freeze thawing and freeze drying

    NARCIS (Netherlands)

    Hinrichs, Wouter; Manceñido, F A; Sanders, N N; Braeckmans, K; De Smedt, S C; Demeester, J; Frijlink, H W

    2006-01-01

    In a previous Study we have shown that the oligosaccharide inulin can prevent aggregation of poly(ethylene glycol) (PEG) coated plasmid DNA/cationic liposome complexes ('' PEGylated lipoplexes '') during freeze thawing and freeze drying [Hinrichs et al., 2005. J. Control. Release 103, 465]. By

  5. Influence of freeze-thaw cycling on the resilient modulues of PFBC materials

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, W.E.; Butalia, T.S.; Meek, B.L. [Ohio State University, Columbus, OH (United States). Dept. of Civil and Environmental Engineering and Geodetic Science

    1999-01-01

    The dynamic stress-strain characteristics of a Pressurized Fluidized Bed Combustion (PFBC) material, before and after freeze and thaw cycling, were studied to evaluate its suitability as a substitute for conventional road construction materials in the design of flexible pavement systems. Samples compacted in the laboratory at two different moisture contents (optimum and 8% above optimum) were cyclically load tested after being allowed to cure for various duration. The results of the cyclic tests are presented in terms of the Resilient Modulus, which is a measure of the elastic property of the soil supporting the roadway. The modulus of the samples compacted near the optimum moisture content compared satisfactorily with data available for conventional materials. Samples compacted at moisture contents higher than the optimum exhibited a significant reduction in a resilient modulus values after freeze-thaw cycling. This comparing indicates that properly compacted PFBC holds good promise as a subgrade material in the construction of low traffic volume roads. 13 refs., 5 figs., 1 tab.

  6. Review. Freeze-casting: Fabrication of highly porous and hierarchical ceramic supports for energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Gaudillere, C.; Serra, J. M.

    2016-05-01

    The manufacture of structured ceramic porous support knows an important boom since more than a decade with the development of new shaping techniques. Among the most promising ones, the freeze-casting also called Ice-Tem plating allows the fabrication of ceramic parts exhibiting high porosity (>50%) and vertically aligned and hierarchically organized pores. Such structures were firstly conceived for biomedical applications like bone substitute and tissue engineering, but the distinctive features of freeze-cast structures have attracted the attention of diverse scientific fields, especially in high temperature ceramic-based energy production systems. Indeed, technologies like (a) Solid Oxide Fuel Cell (SOFC) and Electrolyser Cell (SOEC), (b) gas separation (O{sub 2}, H{sub 2}) by asymmetric supported membranes based on mixed ionic and electronic conductors (MIEC) or hydrogen-permeable metals, and (c) Catalytic Membrane Reactor (CMR) systems present a porous component in their physical structure. This latest, presenting a tortuous pathway for gas access and as a consequence, a high transport limitation, is known to be a limiting component for the operation at high flow streams that would enable to reach industrial target. (Author)

  7. Increasing the aperture of x-ray mosaic lenses by freeze drying

    International Nuclear Information System (INIS)

    Koch, F; Marschall, F; Meiser, J; Márkus, O; Faisal, A; Schröter, T; Meyer, P; Kunka, D; Last, A; Mohr, J

    2015-01-01

    Point focus x-ray mosaic lenses are limited in aperture by the aspect ratio that can be reached in the micro fabrication process. In lithography based micro fabrication processes, which are used to fabricate the lens pillar structures, the achievable aspect ratio is restricted by structure collapse due to capillary forces which occur during drying after development. Capillary forces can be avoided by freeze drying, hence avoiding the direct phase change from liquid to gas. Substituting conventional drying by freeze drying using cyclohexane at a temperature of  −10 °C, we could increase the achievable aspect ratio for the triangular pillar structures with edge length of 10 to 45 µm of the x-ray mosaic lenses by up to a factor of 2.2 with no further changes in process, material or structural geometry. A maximum aspect ratio of 30 was achieved for pillars with 10 µm edge length. The process can readily be employed to other structures or lithography techniques. (paper)

  8. Heterogeneous freezing of super cooled water droplets in micrometre range- freezing on a chip

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    A new setup to analyse the freezing behaviour of ice nucleation particles (INPs) dispersed in aqueous droplets has been developed with the aim to analyse ensembles of droplets with sizes in the micrometre range, in which INPs are immersed. Major disadvantages of conventional drop-freezing experiments like varying drop sizes or interactions between the water- oil mixture and the INP, were solved by introducing a unique freezing- chip consisting of an etched and sputtered 15x15x1 mm gold-plated silicon or pure gold film (Pummer et al., 2012; Zolles et al., 2015). Using this chip, isolated micrometre-sized droplets can be generated with sizes similar to droplets in real world clouds. The experimental set-up for drop-freezing experiments was revised and improved by establishing automated process control and image evaluation. We were able to show the efficiency and accuracy of our setup by comparing measured freezing temperatures of different INPs (Snomax®, K- feldspar, birch pollen (Betula pendula) washing water, juniper pollen suspension (Juniperus communis) and ultrapure water) with already published results (Atkinson et al., 2013; Augustin et al., 2013; Pruppacher and Klett, 1997; Pummer et al., 2012; Wex et al., 2015; Zolles et al., 2015). Comparison of our measurements with literature data show the important impact of droplet size, INP concentration and number of active sites on the T50 values. Here, the new set-up exhibits its strength in reproducibility and accuracy which is due to the defined and isolated droplets. Finally, it opens a temperature window down to -37˚ C for freezing experiments which was not accessible with former traditional approaches .Atkinson, J. D., Murray, B. J., Woodhouse, M. T., Whale, T. F., Baustian, K. J., Carslaw, K. S., Dobbie, S., O'Sullivan, D., and Malkin, T. L.: The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds (vol 498, pg 355, 2013), Nature, 500, 491-491, 2013. Augustin, S., Wex, H

  9. Physical Stability of Freeze-Dried Isomalt Diastereomer Mixtures

    DEFF Research Database (Denmark)

    Koskinen, Anna-Kaisa; Fraser-Miller, Sara J.; Bøtker, Johan P.

    2016-01-01

    Purpose Isomalt is a sugar alcohol used as an excipient in commercially available solid oral dosage forms. The potential of isomalt as a novel freeze-drying excipient was studied in order to increase knowledge of the behavior of isomalt when it is freeze-dried. Methods Isomalt was freeze-dried in......Purpose Isomalt is a sugar alcohol used as an excipient in commercially available solid oral dosage forms. The potential of isomalt as a novel freeze-drying excipient was studied in order to increase knowledge of the behavior of isomalt when it is freeze-dried. Methods Isomalt was freeze......-dried in four different diastereomer compositions and its physical stability was investigated with differential scanning calorimetry, Fourier-transform infrared and Raman spectroscopy, X-ray powder diffraction, Karl-Fischer titration and thermogravimetric analysis in order to verify the solid state form...... of the diastereomer compositions showed signs of physical instability when stored in the highest relative humidity condition. The four different crystalline diastereomer mixtures showed specific identifiable solid state properties. Conclusions Isomalt was shown to be a suitable excipient for freeze-drying. Preferably...

  10. Freeze-Thaw Durability of Air-Entrained Concrete

    Directory of Open Access Journals (Sweden)

    Huai-Shuai Shang

    2013-01-01

    Full Text Available One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles. The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss and internal crack growth (characterized by the loss of dynamic modulus of elasticity. The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to “the test method of long-term and durability on ordinary concrete” GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

  11. Metabolic changes in Avena sativa crowns recovering from freezing.

    Directory of Open Access Journals (Sweden)

    Cynthia A Henson

    Full Text Available Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L. during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants.

  12. Freeze-thaw durability of air-entrained concrete.

    Science.gov (United States)

    Shang, Huai-Shuai; Yi, Ting-Hua

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to "the test method of long-term and durability on ordinary concrete" GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

  13. N-substituted iminodiacetic acids

    International Nuclear Information System (INIS)

    Nunn, A.; Loberg, M.

    1982-01-01

    The chemical preparation of several new N-substituted iminodiacetic acid derivatives are described. These compounds when complexed with sup(99m)Tc provide useful radiopharmaceuticals for the external imaging of the hepatobiliary system. (U.K.)

  14. Effect of freezing temperature on the color of frozen salmon.

    Science.gov (United States)

    Ottestad, Silje; Enersen, Grethe; Wold, Jens Petter

    2011-09-01

    New freezing methods developed with the purpose of improved product quality after thawing can sometimes be difficult to get accepted in the market. The reason for this is the formation of ice crystals that can give the product a temporary color loss and make it less appealing. We have here used microscopy to study ice crystal size as a function of freezing temperature by investigating the voids in the cell tissue left by the ice crystals. We have also investigated how freezing temperature affects the color and the visible absorption spectra of frozen salmon. Freezing temperatures previously determined to be the best for quality after thawing (-40 to -60 °C) were found to cause a substantial loss in perceived color intensity during frozen state. This illustrated the conflict between optimal freezing temperatures with respect to quality after thawing against visual appearance during frozen state. Low freezing temperatures gave many small ice crystals, increased light scattering and an increased absorption level for all wavelengths in the visible region. Increased astaxanthin concentration on the other hand would give higher absorption at 490 nm. The results showed a clear potential of using visible interactance spectroscopy to differentiate between poor product coloration due to lack of pigmentation and temporary color loss due to light scattering by ice crystal. This type of measurements could be a useful tool in the development of new freezing methods and to monitor ice crystal growth during frozen storage. It could also potentially be used by the industry to prove good product quality. In this article we have shown that freezing food products at intermediate to low temperatures (-40 to -80 °C) can result in paler color during frozen state, which could affect consumer acceptance. We have also presented a spectroscopic method that can separate between poor product color and temporary color loss due to freezing. © 2011 Institute of Food Technologists®

  15. Commercial formalin substitutes for histopathology

    DEFF Research Database (Denmark)

    Prentø, P; Lyon, H

    1997-01-01

    We compared the performance of six commercial fixatives proposed to be formalin substitutes with the performance of buffered formalin, Clarke's ethanol-acetic acid, and ethanol, using rat liver, small intestine, and kidney. We investigated the rate of penetration, mode of fixation, extent of prot...... was obtained by combining formalin fixation with antigen retrieval. We conclude that none of the proposed commercial substitutes for buffered formalin are adequate for critical histology or histopathology....

  16. Stores, Prices, and Currency Substitution

    OpenAIRE

    Gabriele, Camera; Winkler, Johannes

    1999-01-01

    We study endogenous currency substitution in a decentralized trade environment. Sellers maximize profits from sales of imperfectly substitutable goods by posting prices in either one of two currencies. A unique symmetric equilibrium exists where goods are priced only in the local currency. This occurs if foreign trade is sporadic, there is sufficient but not excessive liquidity, and discounting is low. Excess or scarcity of liquidity, however, induces sellers to extract all surplus from bu...

  17. Substitution reactions of technetium complexes

    International Nuclear Information System (INIS)

    Omori, T.

    1997-01-01

    Substitution reactions of a series of technetium complexes are considered in comparison with corresponding reactions of rhenium. Rhenium and technetium complexes are rather inert in substitution reactions, the latter are characterized by greater rate constants when they proceed according to dissociative mechanism. In rare cases when k Tc /k Re id little it is assumed that the reaction proceeds according to the associative mechanism. (author)

  18. SOME STUDIES ABOUT CEREALS BEHAVIOR DURING FREEZE DRYING PROCESS

    Directory of Open Access Journals (Sweden)

    GABRIELA-VICTORIA MNERIE

    2009-05-01

    Full Text Available The paper presents some special method and equipment and the principal advantages of freeze-dried food. The freeze drying is a good method of freeze-drying for make some experiments with many kind of cereals, for the improvement that in food production. It is necessary and is possible to study the corn oil extract, wheat flour, the maltodextrin from corn, modified cornstarch, spice extracts, soy sauce, hydrolyzed wheat gluten, partially hydrogenated soybean and cottonseed oil etc. That is very porous, since it occupies the same volume as the original and so rehydrates rapidly. There is less loss of flavour and texture than with most other methods of drying.

  19. Preparation of freezing quantum state for quantum coherence

    Science.gov (United States)

    Yang, Lian-Wu; Man, Zhong-Xiao; Zhang, Ying-Jie; Han, Feng; Du, Shao-jiang; Xia, Yun-Jie

    2018-06-01

    We provide a method to prepare the freezing quantum state for quantum coherence via unitary operations. The initial product state consists of the control qubit and target qubit; when it satisfies certain conditions, the initial product state converts into the particular Bell diagonal state under the unitary operations, which have the property of freezing of quantum coherence under quantum channels. We calculate the frozen quantum coherence and corresponding quantum correlations, and find that the quantities are determined by the control qubit only when the freezing phenomena occur.

  20. Universal pion freeze-out in heavy-ion collisions.

    Science.gov (United States)

    Adamová, D; Agakichiev, G; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanović, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Z; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B; Ludolphs, W; Maas, A; Marín, A; Milosević, J; Milov, A; Miśkowiec, D; Panebrattsev, Yu; Petchenova, O; Petrácek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schmitz, W; Schukraft, J; Sedykh, S; Shimansky, S; Slívová, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, I; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V

    2003-01-17

    Based on an evaluation of data on pion interferometry and on particle yields at midrapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda(f) reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from the Alternating Gradient Synchrotron to the Relativistic Heavy Ion Collider.

  1. Universal pion freeze-out in heavy-ion collisions

    CERN Document Server

    Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Ludolphs, W; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schükraft, Jürgen; Sedykh, S; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V; Schmitz, W

    2003-01-01

    Based on an evaluation of recent systematic data on two-pion interferometry and on measured particle yields at mid-rapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda_f reaches a value of approximately 2.5 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and its value is constant at all currently available beam energies from AGS to RHIC.

  2. Adaptation to seasonality and the winter freeze

    Directory of Open Access Journals (Sweden)

    Jill Christine Preston

    2013-06-01

    Full Text Available Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, freezing tolerance, endodormancy, and vernalization responsiveness. Despite compelling evidence for multiple independent origins, the level of genetic constraint on the evolution of adaptations to seasonal cold is not well understood. However, the recent increase in molecular genetic studies examining the response of model and crop species to seasonal cold offers new insight into the evolutionary lability of these traits. This insight has major implications for our understanding of complex trait evolution, and the potential role of local adaptation in response to past and future climate change. In this review, we discuss the biochemical, morphological, and developmental basis of adaptations to seasonal cold, and synthesize recent literature on the genetic basis of these traits in a phylogenomic context. We find evidence for multiple genetic links between distinct physiological responses to cold, possibly reinforcing the coordinated expression of these traits. Furthermore, repeated recruitment of the same or similar ancestral pathways suggests that land plants might be somewhat pre-adapted to dealing with temperature stress, perhaps making inducible cold traits relatively easy to evolve.

  3. Drying a tuberculosis vaccine without freezing.

    Science.gov (United States)

    Wong, Yun-Ling; Sampson, Samantha; Germishuizen, Willem Andreas; Goonesekera, Sunali; Caponetti, Giovanni; Sadoff, Jerry; Bloom, Barry R; Edwards, David

    2007-02-20

    With the increasing incidence of tuberculosis and drug resistant disease in developing countries due to HIV/AIDS, there is a need for vaccines that are more effective than the present bacillus Calmette-Guérin (BCG) vaccine. We demonstrate that BCG vaccine can be dried without traditional freezing and maintained with remarkable refrigerated and room-temperature stability for months through spray drying. Studies with a model Mycobacterium (Mycobacterium smegmatis) revealed that by removing salts and cryoprotectant (e.g., glycerol) from bacterial suspensions, the significant osmotic pressures that are normally produced on bacterial membranes through droplet drying can be reduced sufficiently to minimize loss of viability on drying by up to 2 orders of magnitude. By placing the bacteria in a matrix of leucine, high-yield, free-flowing, "vial-fillable" powders of bacteria (including M. smegmatis and M. bovis BCG) can be produced. These powders show relatively minor losses of activity after maintenance at 4 degrees C and 25 degrees C up to and beyond 4 months. Comparisons with lyophilized material prepared both with the same formulation and with a commercial formulation reveal that the spray-dried BCG has better overall viability on drying.

  4. Contamination of freezing soils: Australia's Antarctic opportunity

    International Nuclear Information System (INIS)

    Williams, P.

    2002-01-01

    Last month, the Federal government announced that millions of dollars were to be spent cleaning up Antarctica, for which Australia has special responsibilities. Australia's largesse is especially interesting in a world context. Antarctica, by international agreement, is free of any industrial development - mining, storage of wastes, or any other profit-making activity that would disturb the environment (tourism is allowed under increasingly controlled conditions). The importance of the more or less pristine frigid environment lies in the wide range of scientific research that is carried out there. Sophisticated techniques to improve environmental quality are evidently in the early development stage. That cold-loving organisms can thrive in frozen ground in Antarctica and the Arctic was a discovery so unexpected that few people could grasp its importance. Only later was it found that these bugs can eat up contaminants - and the discovery assumed enormous practical significance. Little is known about how to clean up contamination in freezing soils even though there is a pressing need to solve the growing problem with military, industrial and nuclear waste in the Northern Hemisphere

  5. GPR utilization in artificial freezing engineering

    International Nuclear Information System (INIS)

    Song, Lei; Yang, Weihao; Huang, Jiahui; Li, Haipeng; Zhang, Xiaojun

    2013-01-01

    To utilize ground penetrating radar (GPR) in artificial freezing engineering (AFE), the electromagnetic parameters (EMP) of frozen soil were measured using a vector network analyser, which showed that the dielectric permittivity and electric conductivity change abruptly at the boundary between the frozen and the non-frozen soil. Then similarity criteria of GPR model experiments were deduced, and GPR laboratory model experiments and field explorations of AFE were carried out. It was found that for AFE, the GPR travel time and profile characters of anomalies in model experiments were similar to those in field explorations, while the amplitude of GPR signals in laboratory model experiments were much stronger than those in field explorations. Numerical simulations were also implemented to analyse the relationship between model experiments and field explorations, which further told us why we could easily find the targets by GPR in the laboratory but not in field explorations. The outputs showed that GPR could be used to detect the thickness of the frozen wall and to find unfrozen soil defects, even though the amplitude of the reflective signals were much weaker than those of laboratory experiments. The research findings have an important theoretical value for AFE and permafrost region engineering, and the deduced GPR similarity criteria could be widely used in other GPR model experiments. (paper)

  6. Effect of freezing extender composition and male line on semen traits and reproductive performance in rabbits.

    Science.gov (United States)

    Viudes-de-Castro, M P; Lavara, R; Safaa, H M; Marco-Jiménez, F; Mehaisen, G M K; Vicente, J S

    2014-05-01

    This study was conducted to elucidate the effect of different freezing extenders on two lines selected for hyperprolificacy and longevity (H and LP, respectively). In extender A, dimethyl sulphoxide (Me2SO) and sucrose were used as cryoprotectants. In extenders B and C, the sucrose was replaced by 20% egg yolk, and in extender C the Me2SO was substituted by acetamide. Semen was packaged in 0.25 ml plastic straws and cooled at 5°C for 45 min, and then was frozen in liquid nitrogen vapour for 10 min before being plunged into the liquid nitrogen. Thawing was carried out by immersing the straws in a water bath at 50°C for 10 s. Frozen-thawed semen characteristics and reproductive parameters were affected by freezing. Extender C showed significantly lower post-thawing quality traits than any of the three extenders. Acrosome integrity was significantly improved when Me2SO was used as cryoprotectant. Sucrose replacement by 20% egg yolk had no effect on acrosome integrity but provided significantly lower sperm motility and viability. Freezing extender affected fertility rate, total born, number of implantation sites and gestational losses, obtaining better results when extender A was used. The acrosomal integrity after frozen-thawed process showed a significant correlation with fertility at 12th day and also at birth, indicating that an increase in acrosomal integrity leads to an increase in both fertilities (12th day and at birth). A positive correlation between motility of semen and implantation sites was found. The post-thawing quality traits of semen were not affected by the genetic line, although LP line showed higher total born and lower foetal and gestational losses. The findings of this study suggest that freezing extender composition has a significant effect on the success of rabbit sperm for preservation, and when Me2SO was used as permeable cryoprotectant sucrose provided better protection compared with egg yolk and improved reproductive traits, and, on the

  7. Normal freezing of ideal ternary systems of the pseudobinary type

    Science.gov (United States)

    Li, C. H.

    1972-01-01

    Perfect liquid mixing but no solid diffusion is assumed in normal freezing. In addition, the molar compositions of the freezing solid and remaining liquid, respectively, follow the solidus and liquidus curves of the constitutional diagram. For the linear case, in which both the liquidus and solidus are perfectly straight lines, the normal freezing equation giving the fraction solidified at each melt temperature and the solute concentration profile in the frozen solid was determined as early as 1902, and has since been repeatedly published. Corresponding equations for quadratic, cubic or higher-degree liquidus and solidus lines have also been obtained. The equation of normal freezing for ideal ternary liquid solutions solidified into ideal solid solutions of the pseudobinary type is given. Sample computations with the use of this new equation were made and are given for the Ga-Al-As system.

  8. CFD modelling of condensers for freeze-drying processes

    Indian Academy of Sciences (India)

    Freeze-drying; condenser; CFD simulation; mathematical modelling; ... it is used for the stabilization and storage of delicate, heat-sensitive materials .... The effect of the surface mass transfer has been included in the continuity equation and.

  9. Accelerated storage testing of freeze-dried Pseudomonas ...

    African Journals Online (AJOL)

    Accelerated storage testing of freeze-dried Pseudomonas fluorescens BTP1, ... of all P. fluorescens strains were not significantly different and thermal inactivation ... useful to the development of improved reference materials and samples held ...

  10. Freezing Point Depressions of Phase Change CO2 Solvents

    DEFF Research Database (Denmark)

    Arshad, Muhammad Waseem; Fosbøl, Philip Loldrup; von Solms, Nicolas

    2013-01-01

    Freezing point depressions (FPD) in phase change solvents containing 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA) were measured using a modified Beckmann apparatus. The measurements were performed for the binary aqueous DEEA and MAPA solutions, respectively...

  11. A rapidly negotiable first-stage nuclear freeze

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This paper reports on the objective of a nuclear freeze which is to slow down or stop the so-far inexorable development and deployment of more and more (read destructive and deadly) nuclear warheads. The essential notion is not new. The proposed treaty for a comprehensive ban on nuclear tests that was very nearly negotiated in 1959 was perhaps the first serious effort to obtain a nuclear freeze, albeit a partial one. Growing concern about the nuclear arms race has led to greatly increased interest in much broader and more effective freezes. A comprehensive nuclear freeze, one that would stop all stages in the manufacture, testing, and deployment of nuclear warheads, would clearly be very desirable and have a great impact. It would not, however, deal with the other worrisome aspects of nuclear weapons, which is the very large number of such weapons that already exist

  12. Optoacoustic laser monitoring of cooling and freezing of tissues

    International Nuclear Information System (INIS)

    Larin, Kirill V; Larina, I V; Motamedi, M; Esenaliev, R O

    2002-01-01

    Real-time monitoring of cooling and freezing of tissues, cells, and other biological objects with a high spatial and time resolution, which is necessary for selective destruction of cancer and benign tumours during cryotherapy, as well as for preventing any damage to the structure and functioning of biological objects in cryobiology, is considered. The optoacoustic method, based on the measurement and analysis of acoustic waves induced by short laser pulses, is proposed for monitoring the cooling and freezing of the tissue. The effect of cooling and freezing on the amplitude and time profile of acoustic signals generated in real tissues and in a model object is studied. The experimental results indicate that the optoacoustic laser technique can be used for real-time monitoring of cooling and freezing of biological objects with a submillimeter spatial resolution and a high contrast. (laser biology and medicine)

  13. RESEARCH OF MOISTURE MIGRATION DURING PARTIAL FREEZING OF GROUND BEEF

    Directory of Open Access Journals (Sweden)

    V. M. Stefanovskiy

    2016-01-01

    Full Text Available The concept of «ideal product» is proposed for the study of mass transfer during partial freezing of food products by freezing plate. The ideal product is a product, in which number of factors affecting the «real product» (meat are excluded. These factors include chemical composition of meat, quality grade of raw material (NOR, DFD, PSE, cryoscopic temperature that determines the degree of water transformation into ice, the phenomenon of osmosis, rate of freezing, etc. By using the concept of «ideal product» and its implementation in a physical experiment, it is proved that the “piston effect” causing the migration of moisture is due to frozen crust formation during partial freezing of the body. During partial freezing of the product by freezing plate, «ideal» and «real» food environment is transformed from closed system into open one with inflow of moisture to unfrozen part of the body. In the «ideal product», there is an expulsion of unfrozen moisture from freezing front, so the water appears on the body surface. Thus, the displacement of moisture increases by the same law, according to which the thickness (weight of frozen layer increases. During partial freezing of ground meat, moisture does not appear on the surface of the product, but hydrates the unfrozen part of meat. The reason of this phenomenon is the expulsion of water during formation of frozen crust and water-binding capacity of meat.

  14. Ice, Ice, Baby? A Sociological Exploration of Social Egg Freezing

    OpenAIRE

    Baldwin, K.

    2016-01-01

    Social egg freezing is a fertility preservation strategy which enables women to preserve a number of healthy unfertilised eggs for potential future use when faced with the threat of age-related fertility decline. The overall aim of this thesis was to explore how women understand, construct and experience social egg freezing in the context of debates surrounding reproductive ‘choice’ and ‘delayed motherhood’. The study sought to provide insights into how women perceive the risks and benefi...

  15. Simulation Study on Freeze-drying Characteristics of Mashed Beef

    OpenAIRE

    Tambunan, Armansyah H; Solahudin, M; Rahajeng, Estri

    2000-01-01

    Drying characteristic of a particular product is important in analyzing the appropriateness of the drying method for the product. This is especially important for freeze drying, which is known as the most expensive drying method, asideji-om its good drying quality. The objectives of this experiment are to develop a computer simulation program using a retreating drying-frontmodel for predicting freeze drying characteristics of mashed nteat, especially for the influence of sublimation temperatu...

  16. Freeze concentration of dairy products Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Best, D.E.; Vasavada, K.C.

    1993-09-01

    An efficient, electrically driven freeze concentration system offers potential for substantially increasing electricity demand while providing the mature dairy industry with new products for domestic and export markets together with enhanced production efficiencies. Consumer tests indicate that dairy products manufactured from freeze-concentrated ingredients are either preferred or considered equivalent in quality to fresh milk-based products. Economic analyses indicate that this technology should be competitive with thermal evaporation processes on a commercial basis.

  17. Approaches in Substitution of Organic Solvents

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    2000-01-01

    In substitution of harmful chemicals or products with less harmful or harmless ones, there are different approaches according to the different situations, the technical requirements to the substitutes, and the goals for the substitution. Three different cases are presented. The substitution process...

  18. Freeze injury to roots of southern pine seedlings in the USA | South ...

    African Journals Online (AJOL)

    ... and therefore root injury was often overlooked. Many freeze-injured seedlings died within two months of the freeze event. Since freeze injury symptoms to roots were overlooked, foresters offered various reasons (other than the freeze) for the poor seedling performance. Keywords: acclimation, frost, nursery, Pinus elliottii, ...

  19. Mechanisms of deterioration of nutrients. [improved quality of freeze-dried foods

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1978-01-01

    Methods for improving the quality of freeze-dried foods were investigated. Areas discussed include: (1) microstructure of freeze-dried systems, (2) structural changes in freeze-dried systems, (3) artificial food matrices, and (4) osmotic preconcentration to yield improved freeze-dried products.

  20. Quality Evaluation of Pork with Various Freezing and Thawing Methods

    Science.gov (United States)

    2014-01-01

    In this study, the physicochemical and sensory quality characteristics due to the influence of various thawing methods on electro-magnetic and air blast frozen pork were examined. The packaged pork samples, which were frozen by air blast freezing at −45℃ or electro-magnetic freezing at −55℃, were thawed using 4 different methods: refrigeration (4±1℃), room temperature (RT, 25℃), cold water (15℃), and microwave (2450 MHz). Analyses were carried out to determine the drip and cooking loss, water holding capacity (WHC), moisture content and sensory evaluation. Frozen pork thawed in a microwave indicated relatively less thawing loss (0.63-1.24%) than the other thawing methods (0.68-1.38%). The cooking loss after electro-magnetic freezing indicated 37.4% by microwave thawing, compared with 32.9% by refrigeration, 36.5% by RT, and 37.2% by cold water in ham. The thawing of samples frozen by electro-magnetic freezing showed no significant differences between the methods used, while the moisture content was higher in belly thawed by microwave (62.0%) after electro-magnetic freezing than refrigeration (54.8%), RT (61.3%), and cold water (61.1%). The highest overall acceptability was shown for microwave thawing after electro-magnetic freezing but there were no significant differences compared to that of the other samples. PMID:26761493

  1. Transcriptome Analysis of Spartina pectinata in Response to Freezing Stress.

    Directory of Open Access Journals (Sweden)

    Gyoungju Nah

    Full Text Available Prairie cordgrass (Spartina pectinata, a perennial C4 grass native to the North American prairie, has several distinctive characteristics that potentially make it a model crop for production in stressful environments. However, little is known about the transcriptome dynamics of prairie cordgrass despite its unique freezing stress tolerance. Therefore, the purpose of this work was to explore the transcriptome dynamics of prairie cordgrass in response to freezing stress at -5°C for 5 min and 30 min. We used a RNA-sequencing method to assemble the S. pectinata leaf transcriptome and performed gene-expression profiling of the transcripts under freezing treatment. Six differentially expressed gene (DEG groups were categorized from the profiling. In addition, two major consecutive orders of gene expression were observed in response to freezing; the first being the acute up-regulation of genes involved in plasma membrane modification, calcium-mediated signaling, proteasome-related proteins, and transcription regulators (e.g., MYB and WRKY. The follow-up and second response was of genes involved in encoding the putative anti-freezing protein and the previously known DNA and cell-damage-repair proteins. Moreover, we identified the genes involved in epigenetic regulation and circadian-clock expression. Our results indicate that freezing response in S. pectinata reflects dynamic changes in rapid-time duration, as well as in metabolic, transcriptional, post-translational, and epigenetic regulation.

  2. Freeze-drying wet digital prints: An option for salvage?

    International Nuclear Information System (INIS)

    Juergens, M C; Schempp, N

    2010-01-01

    On the occasion of the collapse of the Historical Archive of the City of Cologne in March 2009 and the ensuing salvage effort, questions were raised about the use of freeze-drying for soaked digital prints, a technique that has not yet been evaluated for these materials. This study examines the effects of immersion, air-drying, drying in a blotter stack, freezing and freeze-drying on 35 samples of major digital printing processes. The samples were examined visually before, during and after testing; evaluation of the results was qualitative. Results show that some prints were already damaged by immersion alone (e.g. bleeding inks and soluble coatings) to the extent that the subsequent choice of drying method made no significant difference any more. For those samples that did survive immersion, air-drying proved to be crucial for water-sensitive prints, since any contact with the wet surface caused serious damage. Less water-sensitive prints showed no damage throughout the entire procedure, regardless of drying method. Some prints on coated media suffered from minor surface disruption up to total delamination of the surface coating due to the formation of ice crystals during shock-freezing. With few exceptions, freeze-drying did not cause additional damage to any of the prints that hadn't already been damaged by freezing. It became clear that an understanding of the process and materials is important for choosing an appropriate drying method.

  3. Effects of freezing, freeze drying and convective drying on in vitro gastric digestion of apples.

    Science.gov (United States)

    Dalmau, Maria Esperanza; Bornhorst, Gail M; Eim, Valeria; Rosselló, Carmen; Simal, Susana

    2017-01-15

    The influence of processing (freezing at -196°C in liquid N2, FN sample; freeze-drying at -50°C and 30Pa, FD sample; and convective drying at 60°C and 2m/s, CD sample) on apple (var. Granny Smith) behavior during in vitro gastric digestion was investigated. Dried apples (FD and CD samples) were rehydrated prior to digestion. Changes in carbohydrate composition, moisture, soluble solids, acidity, total polyphenol content (TPC), and antioxidant activity (AA) of apple samples were measured at different times during digestion. Processing resulted in disruption of the cellular structure during digestion, as observed by scanning electron microscopy, light microscopy, and changes in carbohydrate composition. Moisture content increased (6-11% dmo), while soluble solids (55-78% dmo), acidity (44-72% dmo), total polyphenol content (30-61% dmo), and antioxidant activity (41-87%) decreased in all samples after digestion. Mathematical models (Weibull and exponential models) were used to better evaluate the influence of processing on apple behavior during gastric digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted phenyl...

  5. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin

    OpenAIRE

    Kim, Yiseul; Hong, Geun-Pyo

    2016-01-01

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4? for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4?. Despite that SSF was conducted with the ...

  6. Study on dewatering of chemical sludge by freeze-thaw process

    International Nuclear Information System (INIS)

    Xu Shikun; Liu Pin

    1993-01-01

    The treatment of radioactive sludge that is produced from treating radioactive waste water contains radioactively is different from that of non-radioactive sludge. The methods of immersing freeze and simulated two-step freeze have been studied for the elementary properties of simulated low-level radioactive sledge, the effect of freezing temperature, freeze time, and settling time on volume-reduction factor. Some parameters for design of freeze-thaw device are provided

  7. Substituted decision making: elder guardianship.

    Science.gov (United States)

    Leatherman, Martha E; Goethe, Katherine E

    2009-11-01

    The goal of this column is to help experienced clinicians navigate the judicial system when they are confronted with requests for capacity evaluations that involve guardianship (conservatorship). The interface between the growing elderly medical population and increasing requests for substituted decision making is becoming more complex. This column will help practicing psychiatrists understand the medical, legal, and societal factors involved in adult guardianship. Such understanding is necessary in order to effectively perform guardianship evaluations and adequately inform courts, patients, and families about the psychiatric diagnoses central to substituted decision making.

  8. Substitution determination of Fmoc‐substituted resins at different wavelengths

    Science.gov (United States)

    Kley, Markus; Bächle, Dirk; Loidl, Günther; Meier, Thomas; Samson, Daniel

    2017-01-01

    In solid‐phase peptide synthesis, the nominal batch size is calculated using the starting resin substitution and the mass of the starting resin. The starting resin substitution constitutes the basis for the calculation of a whole set of important process parameters, such as the number of amino acid derivative equivalents. For Fmoc‐substituted resins, substitution determination is often performed by suspending the Fmoc‐protected starting resin in 20% (v/v) piperidine in DMF to generate the dibenzofulvene–piperidine adduct that is quantified by ultraviolet–visible spectroscopy. The spectrometric measurement is performed at the maximum absorption wavelength of the dibenzofulvene–piperidine adduct, that is, at 301.0 nm. The recorded absorption value, the resin weight and the volume are entered into an equation derived from Lambert–Beer's law, together with the substance‐specific molar absorption coefficient at 301.0 nm, in order to calculate the nominal substitution. To our knowledge, molar absorption coefficients between 7100 l mol−1 cm−1 and 8100 l mol−1 cm−1 have been reported for the dibenzofulvene–piperidine adduct at 301.0 nm. Depending on the applied value, the nominal batch size may differ up to 14%. In this publication, a determination of the molar absorption coefficients at 301.0 and 289.8 nm is reported. Furthermore, proof is given that by measuring the absorption at 289.8 nm the impact of wavelength accuracy is reduced. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. PMID:28635051

  9. Substitution determination of Fmoc-substituted resins at different wavelengths.

    Science.gov (United States)

    Eissler, Stefan; Kley, Markus; Bächle, Dirk; Loidl, Günther; Meier, Thomas; Samson, Daniel

    2017-10-01

    In solid-phase peptide synthesis, the nominal batch size is calculated using the starting resin substitution and the mass of the starting resin. The starting resin substitution constitutes the basis for the calculation of a whole set of important process parameters, such as the number of amino acid derivative equivalents. For Fmoc-substituted resins, substitution determination is often performed by suspending the Fmoc-protected starting resin in 20% (v/v) piperidine in DMF to generate the dibenzofulvene-piperidine adduct that is quantified by ultraviolet-visible spectroscopy. The spectrometric measurement is performed at the maximum absorption wavelength of the dibenzofulvene-piperidine adduct, that is, at 301.0 nm. The recorded absorption value, the resin weight and the volume are entered into an equation derived from Lambert-Beer's law, together with the substance-specific molar absorption coefficient at 301.0 nm, in order to calculate the nominal substitution. To our knowledge, molar absorption coefficients between 7100 l mol -1  cm -1 and 8100 l mol -1  cm -1 have been reported for the dibenzofulvene-piperidine adduct at 301.0 nm. Depending on the applied value, the nominal batch size may differ up to 14%. In this publication, a determination of the molar absorption coefficients at 301.0 and 289.8 nm is reported. Furthermore, proof is given that by measuring the absorption at 289.8 nm the impact of wavelength accuracy is reduced. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.

  10. Does anxiety cause freezing of gait in Parkinson's disease?

    Directory of Open Access Journals (Sweden)

    Kaylena A Ehgoetz Martens

    Full Text Available Individuals with Parkinson's disease (PD commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers and 17 PD without freezing of gait (Non-Freezers were instructed to walk in two virtual environments: (i across a plank that was located on the ground (LOW, (ii across a plank above a deep pit (HIGH. Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state. Freezers reported higher levels of anxiety compared to Non-Freezers (p < 0.001 and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p < 0.001. Freezers experienced significantly more freezing of gait episodes (p = 0.013 and spent a significantly greater percentage of each trial frozen (p = 0.005 when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD.

  11. Freeze-all cycle for all normal responders?

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2017-02-01

    The purpose of this study is to evaluate the freeze-all strategy in subgroups of normal responders, to assess whether this strategy is beneficial regardless of ovarian response, and to evaluate the possibility of implementing an individualized embryo transfer (iET) based on ovarian response. This was an observational, cohort study performed in a private IVF center. A total of 938 IVF cycles were included in this study. The patients were submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone (GnRH) antagonist protocol and a cleavage-stage day 3 embryo transfer. We performed a comparison of outcomes between the fresh embryo transfer (n = 523) and the freeze-all cycles (n = 415). The analysis was performed in two subgroups of patients based on the number of retrieved oocytes: Group 1 (4-9 oocytes) and Group 2 (10-15 oocytes). In Group 1 (4-9 retrieved oocytes), the implantation rates (IR) were 17.9 and 20.5% (P = 0.259) in the fresh and freeze-all group, respectively; the ongoing pregnancy rates (OPR) were 31 and 33% (P = 0.577) in the fresh and freeze-all group, respectively. In Group 2 (10-15 oocytes), the IR were 22.1 and 30.1% (P = 0.028) and the OPR were 34 and 47% (P = 0.021) in the fresh and freeze-all groups, respectively. Although the freeze-all policy may be related to better in vitro fertilization (IVF) outcomes in normal responders, these potential advantages decrease with worsening ovarian response. Patients with poorer ovarian response do not benefit from the freeze-all strategy.

  12. Microaspiration for high-pressure freezing: a new method for ultrastructural preservation of fragile and sparse tissues for TEM and electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Auer, Manfred; Triffo, W.J.; Palsdottir, H.; McDonald, K.L.; Inman, J.L.; Bissell, M.J.; Raphael, R.M.; Auer, M.; Lee, J.K.

    2008-02-13

    High-pressure freezing is the preferred method to prepare thick biological specimens for ultrastructural studies. However, the advantages obtained by this method often prove unattainable for samples that are difficult to handle during the freezing and substitution protocols. Delicate and sparse samples are difficult to manipulate and maintain intact throughout the sequence of freezing, infiltration, embedding, and final orientation for sectioning and subsequent TEM imaging. An established approach to surmount these difficulties is the use of cellulose microdialysis tubing to transport the sample. With an inner diameter of 200 micrometers, the tubing protects small and fragile samples within the thickness constraints of high-pressure freezing, and the tube ends can be sealed to avoid loss of sample. Importantly, the transparency of the tubing allows optical study of the specimen at different steps in the process. Here, we describe the use of a micromanipulator and microinjection apparatus to handle and position delicate specimens within the tubing. We report two biologically significant examples that benefit from this approach, 3D cultures of mammary epithelial cells and cochlear outer hair cells. We illustrate the potential for correlative light and electron microscopy as well as electron tomography.

  13. Rational design of an influenza subunit vaccine powder with sugar glass technology : preventing conformational changes of haemagglutinin during freezing and freeze-drying

    NARCIS (Netherlands)

    Amorij, J-P; Meulenaar, J; Hinrichs, W L J; Stegmann, T; Huckriede, A; Coenen, F; Frijlink, H W

    2007-01-01

    The development of a stable influenza subunit vaccine in the dry state was investigated. The influence of various carbohydrates, buffer types and freezing rates on the integrity of haemagglutinin after freeze-thawing or freeze-drying was investigated with a range of analytical and immunological

  14. Behavioral service substitution (Chapter 9)

    NARCIS (Netherlands)

    Stahl, C.; Aalst, van der W.M.P.; Bouguettaya, A.; Sheng, Q.Z.; Daniel, F.

    2014-01-01

    Service-oriented design supports system evolution and encourages reuse and modularization. A key ingredient of service orientation is the ability to substitute one service by another without reconfiguring the overall system. This chapter aims to give an overview of the state of the art and open

  15. prismane structure by silicon substitution

    Indian Academy of Sciences (India)

    Using the second-order Møller–Plesset perturbation (MP2) theoretic method and the cc-pVDZ basis set, it is shown that with an increase in the number of carbon atoms substituted by silicon, the [6]-prismane structure becomes increasingly more stable, relative to the two isolated benzene (like) structures. A similar trend is ...

  16. Story of skeletally substituted benzenes

    Indian Academy of Sciences (India)

    Unknown

    values are extensively used to define aromaticity quantitatively.3 In a recent study on ... studies were directed to unravel the subtle ways in which the stability, reactivity, and ..... The singlet–triplet gaps of all the skeletally substituted benzenes ...

  17. 40 CFR Appendix D to Subpart G of... - Substitutes Subject to Use Restrictions and Unacceptable Substitutes

    Science.gov (United States)

    2010-07-01

    ... the following criteria, derived from Society of Automotive Engineers (SAE) standards and recommended... Substitutes] Application Substitute Decision Conditions Comments Electronics Cleaning w/CFC-113 and MCF HFC... Sector [Acceptable Subject to Narrowed Use Limits] Application Substitute Decision Comments Electronics...

  18. Apparatus for freeze drying of biologic and sediment samples

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Freeze drying to obtain water from individual samples, though not complicated, usually requires considerable effort to maintain the cold traps on a 24-hr basis. In addition, the transfer of a sample from sample containers to freeze-dry flasks is usually made with some risk of contamination to the sample. If samples are large, 300 g to 600 g, usually several days are required to dry the samples. The use of an unattended system greatly improves personnel and drying efficiency. Commercial freeze dryers are not readily applicable to the problems of collecting water from individual samples, and lab-designed collectors required sample transfer and continual replenishment of the dry ice. A freeze-dry apparatus for collecting water from individual sediment and/or biological samples was constructed to determine the tritium concentrations in fish for dose calcaluations and the tritium distribution in sediment cores for water movement studies. The freeze, dry apparatus, which can handle eight samples simultaneously and conveniently, is set up for unattended 24-hr operation and is designed to avoid sample transfer problems

  19. Prediction of frozen food properties during freezing using product composition.

    Science.gov (United States)

    Boonsupthip, W; Heldman, D R

    2007-06-01

    Frozen water fraction (FWF), as a function of temperature, is an important parameter for use in the design of food freezing processes. An FWF-prediction model, based on concentrations and molecular weights of specific product components, has been developed. Published food composition data were used to determine the identity and composition of key components. The model proposed in this investigation had been verified using published experimental FWF data and initial freezing temperature data, and by comparison to outputs from previously published models. It was found that specific food components with significant influence on freezing temperature depression of food products included low molecular weight water-soluble compounds with molality of 50 micromol per 100 g food or higher. Based on an analysis of 200 high-moisture food products, nearly 45% of the experimental initial freezing temperature data were within an absolute difference (AD) of +/- 0.15 degrees C and standard error (SE) of +/- 0.65 degrees C when compared to values predicted by the proposed model. The predicted relationship between temperature and FWF for all analyzed food products provided close agreements with experimental data (+/- 0.06 SE). The proposed model provided similar prediction capability for high- and intermediate-moisture food products. In addition, the proposed model provided statistically better prediction of initial freezing temperature and FWF than previous published models.

  20. A theoretical extension of the soil freezing curve paradigm

    Science.gov (United States)

    Amiri, Erfan A.; Craig, James R.; Kurylyk, Barret L.

    2018-01-01

    Numerical models of permafrost evolution in porous media typically rely upon a smooth continuous relation between pore ice saturation and sub-freezing temperature, rather than the abrupt phase change that occurs in pure media. Soil scientists have known for decades that this function, known as the soil freezing curve (SFC), is related to the soil water characteristic curve (SWCC) for unfrozen soils due to the analogous capillary and sorptive effects experienced during both soil freezing and drying. Herein we demonstrate that other factors beyond the SFC-SWCC relationship can influence the potential range over which pore water phase change occurs. In particular, we provide a theoretical extension for the functional form of the SFC based upon the presence of spatial heterogeneity in both soil thermal conductivity and the freezing point depression of water. We infer the functional form of the SFC from many abrupt-interface 1-D numerical simulations of heterogeneous systems with prescribed statistical distributions of water and soil properties. The proposed SFC paradigm extension has the appealing features that it (1) is determinable from measurable soil and water properties, (2) collapses into an abrupt phase transition for homogeneous media, (3) describes a wide range of heterogeneity within a single functional expression, and (4) replicates the observed hysteretic behavior of freeze-thaw cycles in soils.

  1. Does Anxiety Cause Freezing of Gait in Parkinson's Disease?

    Science.gov (United States)

    Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

    2014-01-01

    Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (panxiety when walking across the HIGH plank compared to the LOW (panxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

  2. Geometric origin of dynamically induced freezing of quantum evolution

    International Nuclear Information System (INIS)

    Matos-Abiague, A.; Berakdar, J.

    2006-01-01

    The phenomenon of dynamical, field-induced freezing of quantum evolution is discussed. It occurs when a time-dependent state is dynamically driven in such a way that the evolution of the corresponding wave function is effectively localized within a small region in the projective Hilbert space. As a consequence, the dynamics of the system is frozen and the expectation values of all physical observables hardly change with time. Necessary and sufficient conditions for inducing dynamical freezing are inferred from a general analysis of the geometry of quantum evolution. The relevance of the dynamical freezing for a sustainable in time, dynamical control is discussed and exemplified by a study of the coherent control of the kicked rotor motion

  3. A case history of a tunnel constructed by ground freezing

    Science.gov (United States)

    Lacy, H. S.; Jones, J. S., Jr.; Gidlow, B.

    Artificial ground freezing was used for structural support and groundwater control for a 37 m long, 3.2 m diameter tunnel located about 2 m beneath high speed railroad lines in Syracuse, New York. A double row of freeze pipes spaced approximately 0.9 m on-center was used around the periphery of the tunnel above the spring line, while only a single row of freeze pipes was required below the spring line. Excavation of the frozen soil within the tunnel was accomplished with a small road header tunnel boring machine. The results of in situ testing of frozen soil, laboratory testing of frozen soils, computer analysis to predict stress deformation-time characteristics under static and cyclic loading, the instrumentation program including a comparison of estimated and measured performance are discussed.

  4. Cryochemistry: freezing effect on peptide coupling in different organic solutions.

    Science.gov (United States)

    Vajda, T; Szókán, G; Hollósi, M

    1998-06-01

    The freezing effect on peptide coupling in organic solutions of different polarity has been investigated and compared with the results obtained in liquid phase. The model reaction of DCC-activated coupling of Boc-Ala-Phe-OH with H-Ala-OBu(t) has been carried out in dioxane, dimethylsulfoxide and formamide, as well as in mixtures (90%/10%, v/v) of dioxane with acetonitrile, dimethylformamide, dimethylsulfoxide and formamide. The reactions have been traced and evaluated by RP-HPLC analysis. Freezing the reaction mixture resulted in all cases in a significant suppression of the N-dipeptidylurea side-product formation together with a slight decrease of tripeptide epimerization. The coupling yields and the side effects depended on the solvent, with the dioxane and dioxane/acetonitrile mixture produced the best results. The role of freezing and solvent in the improved results is discussed.

  5. Cod and rainbow trout as freeze-chilled meal elements

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Nielsen, Jette; Jørgensen, Bo

    2010-01-01

    Meal elements' are elements of a meal, e.g. portions of pre-fried meat, sauces, frozen fish or pre-processed vegetables typically prepared industrially. The meal elements are distributed to professional satellite kitchens, where the staff can combine them into complete meals. Freeze......-chilling is a process consisting of freezing and frozen storage followed by thawing and chilled storage. Combining the two would enable the manufacturer to produce large quantities of frozen meal elements to be released into the chill chain according to demand. We have studied the influence of freeze...... days of chilled storage, and the corresponding time for rainbow trout was 10 days. After this period the sensory quality decreased and chemical indicators of spoilage were seen to increase. CONCLUSION: The consistent quality during storage and the high-quality shelf life are practically applicable...

  6. Positron probe to study the freezing of nanodroplets

    International Nuclear Information System (INIS)

    Pujari, P.K.

    2010-01-01

    Positron is an excellent in situ probe to study the phase behavior of fluid confined in nanodomains. The study of phase behavior (freezing/melting) of nano confined fluid or nanodroplet has great relevance in fundamental research as well as applications in nano-tribology, nanofabrication, membrane separation, interfacial adhesion and lubrication. It is seen that the properties of freezing/melting of nanodroplets are different from their bulk behavior due to the combined effects of finite size, surface force, surface anisotropy, pore disorder and reduced dimensionality. We have used positron annihilation spectroscopy (PAS) to study the freezing/melting behavior of different organic liquids like benzene, ethylene glycol and isopropanol confined in nanopores of ZSM5 zeolite and silica gel

  7. The effect of dryer load on freeze drying process design.

    Science.gov (United States)

    Patel, Sajal M; Jameel, Feroz; Pikal, Michael J

    2010-10-01

    Freeze-drying using a partial load is a common occurrence during the early manufacturing stages when insufficient amounts of active pharmaceutical ingredient (API) are available. In such cases, the immediate production needs are met by performing lyophilization with less than a full freeze dryer load. However, it is not obvious at what fractional load significant deviations from full load behavior begin. The objective of this research was to systematically study the effects of variation in product load on freeze drying behavior in laboratory, pilot and clinical scale freeze-dryers. Experiments were conducted with 5% mannitol (high heat and mass flux) and 5% sucrose (low heat and mass flux) at different product loads (100%, 50%, 10%, and 2%). Product temperature was measured in edge as well as center vials with thermocouples. Specific surface area (SSA) was measured by BET gas adsorption analysis and residual moisture was measured by Karl Fischer. In the lab scale freeze-dryer, the molar flux of inert gas was determined by direct flow measurement using a flowmeter and the molar flux of water vapor was determined by manometric temperature measurement (MTM) and tunable diode laser absorption spectroscopy (TDLAS) techniques. Comparative pressure measurement (capacitance manometer vs. Pirani) was used to determine primary drying time. For both 5% mannitol and 5% sucrose, primary drying time decreases and product temperature increases as the load on the shelves decreases. No systematic variation was observed in residual moisture and vapor composition as load decreased. Further, SSA data suggests that there are no significant freezing differences under different load conditions. Independent of dryer scale, among all the effects, variation in radiation heat transfer from the chamber walls to the product seems to be the dominant effect resulting in shorter primary drying time as the load on the shelf decreases (i.e., the fraction of edge vials increases).

  8. Freezing tolerance of ectomycorrhizal fungi in pure culture.

    Science.gov (United States)

    Lehto, Tarja; Brosinsky, Arlena; Heinonen-Tanski, Helvi; Repo, Tapani

    2008-10-01

    The ability to survive freezing and thawing is a key factor for the existence of life forms in large parts of the world. However, little is known about the freezing tolerance of mycorrhizal fungi and their role in the freezing tolerance of mycorrhizas. Threshold temperatures for the survival of these fungi have not been assessed experimentally. We grew isolates of Suillus luteus, Suillus variegatus, Laccaria laccata, and Hebeloma sp. in liquid culture at room temperature. Subsequently, we exposed samples to a series of temperatures between +5 degrees C and -48 degrees C. Relative electrolyte leakage (REL) and re-growth measurements were used to assess the damage. The REL test indicated that the lethal temperature for 50% of samples (LT(50)) was between -8.3 degrees C and -13.5 degrees C. However, in the re-growth experiment, all isolates resumed growth after exposure to -8 degrees C and higher temperatures. As many as 64% of L. laccata samples but only 11% in S. variegatus survived -48 degrees C. There was no growth of Hebeloma and S. luteus after exposure to -48 degrees C, but part of their samples survived -30 degrees C. The fungi tolerated lower temperatures than was expected on the basis of earlier studies on fine roots of ectomycorrhizal trees. The most likely freezing tolerance mechanism here is tolerance to apoplastic freezing and the concomitant intracellular dehydration with consequent concentrating of cryoprotectant substances in cells. Studying the properties of fungi in isolation promotes the understanding of the role of the different partners of the mycorrhizal symbiosis in the freezing tolerance.

  9. Cost-Effectiveness of the Freeze-All Policy.

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2015-08-01

    To evaluate the cost-effectiveness of freeze-all cycles when compared to fresh embryo transfer. This was an observational study with a cost-effectiveness analysis. The analysis consisted of 530 intracytoplasmic sperm injection (ICSI) cycles in a private center in Brazil between January 2012 and December 2013. A total of 530 intracytoplasmic sperm injection (ICSI) cycles - 351 fresh embryo transfers and 179 freeze-all cycles - with a gonadotropin-releasing hormone (GnRH) antagonist protocol and day 3 embryo transfers. The pregnancy rate was 31.1% in the fresh group and 39.7% in the freeze-all group. We performed two scenario analyses for costs. In scenario 1, we included those costs associated with the ICSI cycle (monitoring during controlled ovarian stimulation [COS], oocyte retrieval, embryo transfer, IVF laboratory, and medical costs), embryo cryopreservation of supernumerary embryos, hormone measurements during COS and endometrial priming, medication use (during COS, endometrial priming, and luteal phase support), ultrasound scan for frozen- thawed embryo transfer (FET), obstetric ultrasounds, and miscarriage. The total cost (in USD) per pregnancy was statistically lower in the freeze-all cycles (19,156.73 ± 1,732.99) when compared to the fresh cycles (23,059.72 ± 2,347.02). Even in Scenario 2, when charging all of the patients in the freeze-all group for cryopreservation (regardless of supernumerary embryos) and for FET, the fresh cycles had a statistically significant increase in treatment costs per ongoing pregnancy. The results presented in this study suggest that the freeze-all policy is a cost-effective strategy when compared to fresh embryo transfer.

  10. FY 2017 Status of Sodium Freezing and Remelting Tests

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States); Boron, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Momozaki, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Chojnowski, D. B. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Reed, C. B. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-09-15

    The Sodium Freezing and Remelting experiment facility at Argonne National Laboratory has been significantly modified and improved. The main improvement was replacement of the two original stainless steel test sections that had strain gages limited by their bonds to the stainless steel to maximum temperatures of 350°C with a single new test section with strain gages that can be utilized up to 980°C and a thin wall to enhance measured strains. Wetting of stainless steel by sodium within a practical time of one to a few days is expected to require temperatures of 450°C or greater. Thus, the higher temperature strain gages enable wetting in a short time of a few days. Wetting below 350°C would have required an impractically long time of at least weeks. Other improvements included upgrading of the loop configuration, incorporation of a cold finger to purify sodium, a new data acquisition system, and reinstallation of the many heaters, heater controllers, and thermocouples. After the loop had been heated to 400°C for about two hours, an initial sodium freezing test was conducted. It is thought that the sodium might have at least partially wetted the stainless steel wall under these conditions. The strain gage measurements indicate that an incremental step inward deformation of the test section thin wall occurred as the temperature decreased through the sodium freezing temperature. This behavior is consistent with sodium initially adhering to the stainless steel inner wall but breaking away from the wall as the freezing sodium contracted. Conduct of additional sodium freezing tests under well wetted conditions was prevented as a result of stoppage of all electrical work at Argonne by the Laboratory Director on July 25, 2017. A pathway to resuming electrical work is now in place at Argonne and additional sodium freezing testing will resume next fiscal year.

  11. Experimental Investigation of Thermal Conductivity of Meat During Freezing

    Science.gov (United States)

    Shinbayeva, A.; Arkharov, I.; Aldiyarov, A.; Drobyshev, A.; Zhubaniyazova, M.; Kurnosov, V.

    2017-04-01

    The cryogenic technologies of processing and storage of agricultural products are becoming increasingly indispensable in the food industry as an important factor of ensuring food safety. One of such technologies is the shock freezing of meat, which provides a higher degree of preservation of the quality of frozen products in comparison with traditional technologies. The thermal conductivity of meat is an important parameter influencing the energy consumption in the freezing process. This paper presents the results of an experimental investigation of the temperature dependence of the thermal conductivity of beef. The measurements were taken by using a specially designed measurement cell, which allows covering the temperature range from 80 to 300 K.

  12. Entree Production Guides for Cook/Freeze Systems

    Science.gov (United States)

    1983-03-01

    92.29 50.00 22,680 1. Fill roasting pans with cut-up chicken . Salt 0.35 0.19 86 2. Combine ingredients listed Pepper, black 0.07 0.04 18 in this...INSTALLATIONS FREEZING RECIPES HOSPITAL FEEDING i, WACT (Vmentbs m reves - W neete y lsmer ~lr y block nguber) Entree production guides have been...control and better use of personnel. Standard recipes must be adapted to production guides for use in cook/freeze systems. Products must withstand the

  13. Freezing Point Determination of Water–Ionic Liquid Mixtures

    DEFF Research Database (Denmark)

    Liu, Yanrong; Meyer, Anne S.; Nie, Yi

    2017-01-01

    .841 K in thefirst system and at a water mole fraction of 0.657 and 202.565 K inthe second system. Water activities in aqueous IL solutions were predictedby COSMO-RS and COSMO-SAC and compared to water activities derivedfrom the experimentally determined freezing points. The COSMO-RS predictionswere...... closer to the experimental water activities than the COSMO-SACpredictions. The experimental results indicate that the freezing pointsof IL+H2O systems are affected by the nature of both cationsand anions. However, according to the COSMO-RS excess enthalpy predictionresults, the anions have a relatively...

  14. Study on irradiaiton of freezing-dried Wuchang fish

    International Nuclear Information System (INIS)

    Chen Xueling; Cheng Wei; Xiong Guangquan; Ye Lixiu; Chen Yuxia; Guan Jian; He Jianjun

    2008-01-01

    The effects of irradiation on sterilization and storage time for the freezing-dried Wuchang fish were studied. The results show that the number of the coliform group in freezing-dried Wuchang fish irradiated at 1kGy can be acceptable according to the national industrial standard and the number of bacteria decrease from 3100cfu/g to <10cfu/g after irradiation. With the optimal irradiation dose 1kGy the shelf life of Wuchang fish can be extended over one year. (authors)

  15. Accelerated redox reaction between chromate and phenolic pollutants during freezing

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Jinjung; Kim, Jaesung [Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252 (Korea, Republic of); Vetráková, Ľubica [Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Seo, Jiwon [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Heger, Dominik [Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Lee, Changha [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Yoon, Ho-Il [Korea Polar Research Institute (KOPRI), Incheon 21990 (Korea, Republic of); Kim, Kitae, E-mail: ktkim@kopri.re.kr [Korea Polar Research Institute (KOPRI), Incheon 21990 (Korea, Republic of); Kim, Jungwon, E-mail: jwk@hallym.ac.kr [Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252 (Korea, Republic of)

    2017-05-05

    Highlights: • Redox conversion of 4-CP/Cr(VI) was significantly accelerated during freezing. • Accelerated redox conversion in ice is ascribed to the freeze concentration effect. • 4-CP, Cr(VI), and protons are concentrated in the liquid brine by freezing. • Redox conversions of various phenolic pollutants/Cr(VI) were significant in ice. • Freezing-accelerated redox conversion was observed in real polluted water. - Abstract: The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at −20 °C) was compared with the corresponding reaction in water (i.e., at 25 °C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV–vis absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions.

  16. Accelerated redox reaction between chromate and phenolic pollutants during freezing

    International Nuclear Information System (INIS)

    Ju, Jinjung; Kim, Jaesung; Vetráková, Ľubica; Seo, Jiwon; Heger, Dominik; Lee, Changha; Yoon, Ho-Il; Kim, Kitae; Kim, Jungwon

    2017-01-01

    Highlights: • Redox conversion of 4-CP/Cr(VI) was significantly accelerated during freezing. • Accelerated redox conversion in ice is ascribed to the freeze concentration effect. • 4-CP, Cr(VI), and protons are concentrated in the liquid brine by freezing. • Redox conversions of various phenolic pollutants/Cr(VI) were significant in ice. • Freezing-accelerated redox conversion was observed in real polluted water. - Abstract: The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at −20 °C) was compared with the corresponding reaction in water (i.e., at 25 °C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV–vis absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions.

  17. Smart Phones and their Substitutes

    DEFF Research Database (Denmark)

    Bødker, Mads; Gimpel, Gregory; Hedman, Jonas

    2009-01-01

    Drawing on data from a longitudinal field study, this paper investigates the influence of existing, better and stand-alone technology substitutes on the use of smart phones. By applying prospect theory, media richness theory, and business model literature, the purpose of this paper is to improve...... our understanding of the role of substitutes, device content fit issues, and implications for business models by asking the question: What is an effective business model to address the relationship between user preference and the fit of the smart phone and everyday task? The field study data suggest...... the need for business models to recognize that adoption decisions are reference-dependent and strongly influenced by the fit between task and smart phone....

  18. Bone healing and bone substitutes.

    Science.gov (United States)

    Costantino, Peter D; Hiltzik, David; Govindaraj, Satish; Moche, Jason

    2002-02-01

    With the advent of new biomaterials and surgical techniques, the reconstructive surgeon has a wider range of treatment modalities for the rehabilitation and reconstruction of craniofacial skeletal deformities than ever before. These innovative substances act as true bone graft substitutes, thereby allowing the surgeon to avoid the use of autogenous bone grafts and their associated donor site morbidity. Surgeons have long been interested in producing a composite graft that can heal faster by induction, incorporate with surrounding tissues, and be remodeled to resemble native bone. Currently, there are a host of bone graft substitutes available that vary in both their composition and properties. Craniomaxillofacial surgeons must therefore become comfortable with numerous biomaterials to best tailor the treatment for each patient individually. Ongoing investigations into the next phase of tissue engineering will continue to bring us closer to the ability to regenerate or replace bone.

  19. Substituting oil by electric power

    International Nuclear Information System (INIS)

    Lichtenberg, H.

    1981-01-01

    Parting from the development of primary energy use the author refers to the latest investigations and results presented on the 1980 World Energy Conference and with special regard to oil points out the threatening exhaustion of fossil energy resources. Maintaining the economic structure of the Federal Republic of Germany implies an orientation away from oil. Due to its flexible application technology and quasi-inexhaustible energy resources electric power may substantially contribute to oil substitution which as a matter of fact is of particular interest in connection with the heat market. Coal alone cannot substitute both oil and nuclear energy. Thus, the above postulates the use of the latter. Leaving nuclear energy inactive today will effect an increase in the demand for oil the negative consequences of which would weight heavily upon the anyhow unbalanced import/export ratio of the Federal Republic of Germany. (orig.) [de

  20. 40 CFR 721.4420 - Substituted hydroxylamine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted hydroxylamine. 721.4420... Substances § 721.4420 Substituted hydroxylamine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydroxylamine (PMN P-84-492) is...

  1. Substituted Indoleacetic Acids Tested in Tissue Cultures

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1978-01-01

    Monochloro substituted IAA inhibited shoot induction in tobacco tissue cultures about as much as IAA. Dichloro substituted IAA inhibited shoot formation less. Other substituted IAA except 5-fluoro- and 5-bromoindole-3-acetic acid were less active than IAA. Callus growth was quite variable...

  2. Substitutes for School Nurses in Illinois

    Science.gov (United States)

    Vollinger, Linda Jeno; Bergren, Martha Dewey; Belmonte-Mann, Frances

    2011-01-01

    The purpose of this descriptive study was to explore utilization of nurse substitutes in the school setting in Illinois. The literature described personnel who staff the school health office in the absence of the school nurse and the barriers to obtaining nurse substitutes. There were no empirical studies conducted on school nurse substitutes in…

  3. Emerging techniques for assisting and accelerating food freezing processes: A review of recent research progresses.

    Science.gov (United States)

    Cheng, Lina; Sun, Da-Wen; Zhu, Zhiwei; Zhang, Zi

    2017-03-04

    Freezing plays an important role in food preservation and the emergence of rapid freezing technologies can be highly beneficial to the food industry. This paper reviews some novel food freezing technologies, including high-pressure freezing (HPF), ultrasound-assisted freezing (UAF), electrically disturbed freezing (EF) and magnetically disturbed freezing (MF), microwave-assisted freezing (MWF), and osmo-dehydro-freezing (ODF). HPF and UAF can initiate ice nucleation rapidly, leading to uniform distribution of ice crystals and the control of their size and shape. Specifically, the former is focused on increasing the degree of supercooling, whereas the latter aims to decrease it. Direct current electric freezing (DC-EF) and alternating current electric freezing (AC-EF) exhibit different effects on ice nucleation. DC-EF can promote ice nucleation and AC-EF has the opposite effect. Furthermore, ODF has been successfully used for freezing various vegetables and fruit. MWF cannot control the nucleation temperature, but can decrease supercooling degree, thus decreasing the size of ice crystals. The heat and mass transfer processes during ODF have been investigated experimentally and modeled mathematically. More studies should be carried out to understand the effects of these technologies on food freezing process.

  4. Properties of subvisible cirrus clouds formed by homogeneous freezing

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2002-01-01

    Full Text Available Number concentrations and mean sizes of ice crystals and derived microphysical and optical properties of subvisible cirrus clouds (SVCs formed by homogeneous freezing of supercooled aerosols are investigated as a function of temperature and updraft speed of adiabatically ascending air parcels. The properties of such clouds are insensitive to variations of the aerosol number and size distribution. Based on criteria constraining the optical extinction, sedimentation time, and existence time of SVCs, longer-lived (>10min clouds, capable of exerting a measurable radiative or chemical impact, are generated within a narrow range of updraft speeds below 1-2cm s-1 at temperatures below about 215K, with concentrations of ice crystals not exceeding 0.1cm-3. The clouds do not reach an equilibrium state because the ice crystals sediment out of the formation layer typically before the supersaturation is removed. Two important conclusions emerge from this work. First, the above characteristics of SVCs may provide an explanation for why SVCs are more common in the cold tropical than in the warmer midlatitude tropopause region. Second, it seems likely that a limited number (-3 of effective heterogeneous freezing nuclei that nucleate ice below the homogeneous freezing threshold can control the formation and properties of SVCs, although homogeneous freezing nuclei are far more abundant.

  5. Freezing of gait: moving forward on a mysterious clinical phenomenon

    NARCIS (Netherlands)

    Nutt, J.G.; Bloem, B.R.; Giladi, N.; Hallett, M.; Horak, F.B.; Nieuwboer, A.

    2011-01-01

    Freezing of gait (FoG) is a unique and disabling clinical phenomenon characterised by brief episodes of inability to step or by extremely short steps that typically occur on initiating gait or on turning while walking. Patients with FoG, which is a feature of parkinsonian syndromes, show variability

  6. Seeing fearful body language rapidly freezes the observer's motor cortex

    NARCIS (Netherlands)

    Borgomaneri, Sara; Vitale, Francesca; Gazzola, V.; Avenanti, Alessio

    Fearful body language is a salient signal alerting the observer to the presence of a potential threat in the surrounding environment. Although detecting potential threats may trigger an immediate reduction of motor output in animals (i.e., freezing behavior), it is unclear at what point in time

  7. Seeing fearful body language rapidly freezes the observer's motor cortex

    NARCIS (Netherlands)

    Borgomaneri, S.; Vitale, F.; Gazzola, V.; Avenanti, A.

    2015-01-01

    Fearful body language is a salient signal alerting the observer to the presence of a potential threat in the surrounding environment. Although detecting potential threats may trigger an immediate reduction of motor output in animals (i.e., freezing behavior), it is unclear at what point in time

  8. Freeze-thaw resistance of concrete with marginal air content

    Science.gov (United States)

    2007-05-01

    Freeze-thaw resistance is a key durability factor for concrete pavements. Recommendations for the air void system parameters are normally 6 1 percent total air and a spacing factor of : < 0.20 millimeter (mm) (0.008 inch). However, it was observed...

  9. Accelerated storage testing of freeze-dried Pseudomonas ...

    African Journals Online (AJOL)

    Erika-Chris

    Full Length Research Paper ... was possible to compare rate constants of survival for the freeze-dried P. fluorescens ... studying and predicting the survival loss rate of the ... Erlenmeyer flask containing 3000 ml King B medium. ... The strain was grown in 20 L bioreactor (Biolafite) containing 15 L .... fermented banana media.

  10. Freeze Drying of Fruits and Vegetables: A Laboratory Experiment.

    Science.gov (United States)

    Noble, Richard D.

    1979-01-01

    Describes a laboratory experiment for freeze-drying fruits and vegetables which aims to expose college students to the principles of drying and simultaneous heat and mass transfer. The experimental apparatus, procedure of the experiment, and data analysis are also included. (HM)

  11. Monte Carlo simulation of the OCP freezing transition

    International Nuclear Information System (INIS)

    DeWitt, H.E.; Slattery, W.L.; Yang, Juxing

    1992-09-01

    The One Component Plasma (OCP) in three dimensions is a system of classical point charges moving in a fixed uniform neutralizing background. In nature the OCP is a rough approximation of the conditions in a white dwarf star in which one has fully ionized nuclei such as carbon, oxygen, and smaller amounts of heavier elements up to iron all moving in a nearly uniform background provided by relativistically degenerate electrons. The OCP is also a mathematical limiting model for a non-neutral plasma of ions in a Penning trap and cooled to strongly coupled conditions. Similarly, a collection of charge colloidal suspensions in water can exhibit the Coulomb freezing behavior of the OCP. A single dimensionless parameter, Γ is sufficient to describe the system. For very weak coupling, Γ much-lt 1, the thermodynamic properties of the OCP are given rigorously by the Debye-Huckel theory. This paper reports on Monte Carlo simulation of the freezing of the OCP from a random start for particle numbers ranging from 500 to 2000. In one case the authors obtained a perfect bcc lattice, but in most cases the final state would be an imperfect crystal or two different microcrystals, fcc and bcc, growing into each other. With a cluster analysis program the authors looked at the formation of nucleating clusters, and followed the actual freezing process. Roughly 80 particles are needed in a cluster before it starts to grow rapidly and freeze

  12. Truths and myths of oocyte sensitivity to controlled rate freezing.

    Science.gov (United States)

    Coticchio, G; Bonu, M A; Sciajno, R; Sereni, E; Bianchi, V; Borini, A

    2007-07-01

    The mammalian oocyte is especially sensitive to cryopreservation. Because of its size and physiology, it can easily undergo cell death or sub-lethal damage as a consequence of intracellular ice formation, increase in the concentration of solutes and other undesired effects during the conversion of extracellular water into ice. This has generated the belief that oocyte storage cannot be achieved with the necessary efficiency and safety. However, many concerns raised by oocyte freezing are the result of unproven hypotheses or observations conducted under sometimes inappropriate conditions. For instance, spindle organization can undergo damage under certain freezing conditions but not with other protocols. The controversial suggestion that cryopreservation induces cortical granule discharge and zona pellucida hardening somehow questions the routine use of sperm microinjection. Damage to mouse oocytes caused by solute concentration is well documented but, in the human, there is no solid evidence that modifications of freezing mixtures, to prevent this problem, provide an actual advantage. The hope of developing oocyte cryopreservation as a major IVF option is becoming increasingly realistic, but major efforts are still required to clarify the authentic implications of oocyte cryopreservation at the cellular level and identify freezing conditions compatible with the preservation of viability and developmental ability.

  13. Freeze drying method for preparing radiation source material

    International Nuclear Information System (INIS)

    Mosley, W.C.; Smith, P.K.

    1976-01-01

    Fabrication of a neutron source is specifically claimed. A palladium/californium solution is freeze dried to form a powder which, through conventional powder metallurgy, is shaped into a source containing the californium evenly distributed through a palladium metal matrix. (E.C.B.)

  14. Effect of freezing and thawing on UMTRA covers

    International Nuclear Information System (INIS)

    Rager, R.; Smith, G.; Brody, R.

    1988-01-01

    The proposed US Environmental Protection Agency (EPA) groundwater standards (40 CFR 192) require that Uranium Mill Tailings Remedial Action (UMTRA) Project remedial action designs meet low numerical limits for contaminants contained in water or vapor exiting the embankments. To meet the standards, a cover of compacted fine-grained soil is placed over UMTRA Project embankments. One of the functions of this cover is to limit infiltration. The hydraulic conductivity of this infiltration barrier must be low in order to reduce seepage from the cell to the extent necessary to comply with the proposed EPA groundwater standards. Analyses of infiltration barriers covered with rock erosion protection show that the infiltration barriers may become saturated. Accordingly, it is necessary to assure that freezing and thawing of the infiltration barrier materials do not affect the performance of the embankment. A study has been conducted to determine if the hydraulic conductivity of fine-grained clayey soils used or proposed for use in radon/infiltration barriers is affected by repeated freezing and thawing cycles. In addition, a procedure for determining the depth of frost penetration has been developed. Laboratory freeze-thaw tests were undertaken in order to determine if the saturated hydraulic conductivity of clay soils used in UMTRA Project radon/infiltration barriers was affected. The results indicate that an increase of an order of magnitude or more in saturated hydraulic conductivity may occur during repeated freeze-thaw cycles

  15. 7 CFR 58.638 - Freezing the mix.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Freezing the mix. 58.638 Section 58.638 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE...

  16. [Super sweet corn hybrids adaptability for industrial processing. I freezing].

    Science.gov (United States)

    Alfonzo, Braunnier; Camacho, Candelario; Ortiz de Bertorelli, Ligia; De Venanzi, Frank

    2002-09-01

    With the purpose of evaluating adaptability to the freezing process of super sweet corn sh2 hybrids Krispy King, Victor and 324, 100 cobs of each type were frozen at -18 degrees C. After 120 days of storage, their chemical, microbiological and sensorial characteristics were compared with a sweet corn su. Industrial quality of the process of freezing and length and number of rows in cobs were also determined. Results revealed yields above 60% in frozen corns. Length and number of rows in cobs were acceptable. Most of the chemical characteristics of super sweet hybrids were not different from the sweet corn assayed at the 5% significance level. Moisture content and soluble solids of hybrid Victor, as well as total sugars of hybrid 324 were statistically different. All sh2 corns had higher pH values. During freezing, soluble solids concentration, sugars and acids decreased whereas pH increased. Frozen cobs exhibited acceptable microbiological rank, with low activities of mesophiles and total coliforms, absence of psychrophiles and fecal coliforms, and an appreciable amount of molds. In conclusion, sh2 hybrids adapted with no problems to the freezing process, they had lower contents of soluble solids and higher contents of total sugars, which almost doubled the amount of su corn; flavor, texture, sweetness and appearance of kernels were also better. Hybrid Victor was preferred by the evaluating panel and had an outstanding performance due to its yield and sensorial characteristics.

  17. Freezing tolerance of wheat cultivars at the early growing season ...

    African Journals Online (AJOL)

    Cold stress is a worldwide abiotic stress in temperate regions that affects plant development and yield of winter wheat (Triticum aestivum L.) cultivars and other winter crops. This study was conducted to evaluate the effect of freezing stress at the early growing season on survival and also the relationship between resistances ...

  18. Freeze-all cycle in reproductive medicine: current perspectives.

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Kostolias, Alessandra; Sampaio, Marcos; Geber, Selmo

    2017-02-01

    The freeze-all strategy has emerged as an alternative to fresh embryo transfer (ET) during in vitro fertilization (IVF) cycles. Although fresh ET is the norm during assisted reproductive therapies (ART), there are many concerns about the possible adverse effects of controlled ovarian stimulation (COS) over the endometrium. The supra-physiologic hormonal levels that occur during a conventional COS are associated with modifications in the peri-implantation endometrium, which may be related to a decrease in pregnancy rates and poorer obstetric and perinatal outcomes when comparing fresh to frozen-thawed embryo transfers. The main objective of this study was to assess the available literature regarding the freeze-all strategy in IVF cycles, in regards to effectiveness and safety. Although there are many potential advantages in performing a freeze-all cycle over a fresh ET, it seems that the freeze-all strategy is not designed for all IVF patients. There is a need to develop a non-invasive clinical tool to evaluate the endometrial receptivity during a fresh cycle, which enables the selection of patients that would benefit from this strategy. Today, it is reasonable to perform elective cryopreservation of all oocytes/embryos in cases with a risk of OHSS development, and in patients with supra-physiologic hormonal levels during the follicular phase of COS. It is not clear if all normal responders and poor responders may benefit from this strategy.

  19. Standardinng initial cooling of sheep semen before freezing

    African Journals Online (AJOL)

    sheep semen before freezing. C. Kemp. Animal and Dairy Science Research Institute, Private Bag X2,. Irene, 1675 Republic of South Africa. Received 6 June 1985. A practical and repeatable method for the cooling, during the processing phase, of sheep semen, with the aim of minimizing inter-experiment variation is ...

  20. Molecular and genetic basis of freezing tolerance in crucifer species

    NARCIS (Netherlands)

    Heo, J.

    2014-01-01

    Understanding genetic variation for freezing tolerance is important for unraveling an adaptative strategy of species and for finding out an effective way to improve crop productivity to unfavorable winter environments. The aim of this thesis was to examine natural variation for

  1. Anatomy of a Tuition Freeze: The Case of Ontario

    Science.gov (United States)

    Rexe, Deanna

    2015-01-01

    Using two conceptual frameworks from political science--Kingdon's (2003) multiple streams model and the advocacy coalition framework (Sabatier & Jenkins-Smith, 1993)--this case study examines the detailed history of a major tuition policy change in Ontario in 2004: a tuition freeze. The paper explores the social, political, and economic…

  2. Preparation of superconducting powders by freeze-drying

    International Nuclear Information System (INIS)

    Johnson, S.M.; Gusman, M.I.; Rowcliffe, D.J.; Geballe, T.H.; Sun, J.Z.

    1987-01-01

    A method of preparing superconducting powders by freeze-drying is described. Powders produced by this method are homogeneous, have high purities, and are very reactive. Materials sintered from these powders have densities up to 89% of the theoretical density, and exhibit very sharp resistivity drops and large Meissner effects. The microstructure of the materials is very sensitive to the sintering temperature

  3. Freeze-drying of filamentous fungi and yeasts

    NARCIS (Netherlands)

    Tan, C.S.

    2011-01-01

    The aim of this thesis was to optimize the freeze-drying protocol for fungi in general and for those genera that do not survive this preservation method, in particular. To this end, the influence of the cooling rate, the lyoprotectant and the drying process itself was examined. Since most fungi

  4. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian; Zuo, Jian; Lu, Kang-Jia; Chung, Neal Tai-Shung

    2016-01-01

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  5. A heat equation for freezing processes with phase change

    DEFF Research Database (Denmark)

    Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John-Josef

    2016-01-01

    In this work, the stability properties as well as possible applications of a partial differential equation (PDE) with state-dependent parameters are investigated. Among other things, the PDE describes freezing of foodstuff, and is closely related to the (potential) Burgers’ equation. We show that...

  6. Separation of Contaminants in The Freeze/Thaw Process

    Directory of Open Access Journals (Sweden)

    Szpaczyński Janusz A.

    2017-06-01

    Full Text Available These studies examined the concept of concentration and purification of several types of wastewater by freezing and thawing. The experiments demonstrated that freezing of contaminated liquid contributed to concentration of contaminants in solution as well as significant concentration and agglomeration of solid particles. A high degree of purification was achieved for many parameters. The results of comparative laboratory tests for single and multiple freezing are presented. It was found that there was a higher degree of concentration of pollutants in wastewater frozen as man-made snow than in bulk ice. Furthermore, the hypothesis that long storage time of liquid as snow and sufficient temperature gradient metamorphism allows for high efficiency of the concentration process was confirmed. It was reported that the first 30% of the melted liquid volume contained over 90% of all impurities. It gives great opportunities to use this method to concentrate pollutants. The results revealed that the application of this process in full scale is possible. Significant agglomeration of solid particles was also noted. Tests with clay slurry showed that repeated freezing and thawing processes significantly improve the characteristics of slurry for sedimentation and filtration.

  7. Comment on "Infrared freezing of Euclidean QCD observables"

    Czech Academy of Sciences Publication Activity Database

    Caprini, I.; Fischer, Jan

    2007-01-01

    Roč. 76, č. 1 (2007), 018501/1-018501/5 ISSN 1550-7998 R&D Projects: GA MŠk 1P04LA211 Institutional research plan: CEZ:AV0Z10100502 Keywords : QCD * analyticity * infrared freezing Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.696, year: 2007

  8. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian

    2016-06-23

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  9. Freezing-induced self-assembly of amphiphilic molecules

    Science.gov (United States)

    Albouy, P. A.; Deville, S.; Fulkar, A.; Hakouk, K.; Impéror-Clerc, M.; Klotz, M.; Liu, Q.; Marcellini, M.; Perez, J.

    The self-assembly of amphiphilic molecules usually takes place in a liquid phase, near room temperature. Here, using small angle X-ray scattering (SAXS) experiments performed in real time, we show that freezing of aqueous solutions of copolymer amphiphilic molecules can induce self-assembly below 0{\\deg}C.

  10. Capital stock management during a recession that freezes credit markets

    NARCIS (Netherlands)

    Caulkins, J.P.; Feichtinger, G.; Grass, D.; Hartl, R.F.; Kort, Peter; Seidl, A.

    This paper considers the problem of how to price a conspicuous product while maintaining liquidity during a recession which both reduces demand and freezes credit markets. Reducing price would help maintain cash flow, but low prices can erode brand image and, hence, long-term sales. The paper

  11. Growing bubbles and freezing drops: depletion effects and tip singularities

    NARCIS (Netherlands)

    Enriquez Paz y Puente, O.R.

    2015-01-01

    In this thesis, the author investigates the growth of gas bubbles in a supersaturated solution and the freezing of water drops when placed on a cold plate. Supersaturated solutions are common in nature and industry; perhaps the best know examples are carbonated drinks, such as beer or soda. These

  12. Freeze/thaw phenomena in concrete at low temperatures

    DEFF Research Database (Denmark)

    Johannesson, Björn

    2007-01-01

    Freeze/thaw damage in concrete is by general practice concluded to be a problem that can be avoided by using air-entraining agents to develop an air bubble structure in the hardened concrete together with the use of a relatively low water to cement ratio in mix. This fact is true for inner damage...

  13. Experimental research of "microcable in a microconduct" system stability to effect of freezing water

    Science.gov (United States)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Nikulina, Tatiana G.; Alekhin, Ivan N.; Gavryushin, Sergey A.; Nikulin, Aleksey G.; Praporshchikov, Denis E.

    2011-12-01

    Results of experimental researches of "optical microcable in a microduct" system stability to effect of freezing water are presented. It is shown this system is steadier to water freezing in comparison to lighten optical cable in protective polymer tube.

  14. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, Iro; Roelofs, Karin; Stins, John; Jongedijk, Ruud A.; Hagenaars, Muriel A.

    2017-01-01

    Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed

  15. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, Iro; Roelofs, Karin; Stins, John; Jongedijk, Ruud A.; Hagenaars, Muriel A.

    Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed

  16. Freezing of liquid alkali metals as screened ionic plasmas

    International Nuclear Information System (INIS)

    Badirkhan, Z.; Rovere, M.; Tosi, M.P.

    1990-08-01

    The relationship between Wigner crystallization of the classical ionic plasma and the liquid-solid transition of alkali metals is examined within the density wave theory of freezing. Freezing of the classical plasma on a rigid neutralizing background into the bcc structure is first re-evaluated, in view of recent progress in the determination of its thermodynamic functions by simulation and of the known difficulties of the theory relating to the order parameter at the (200) star of reciprocal lattice vectors. Freezing into the fcc structure is also considered in this context and found to be unfavoured. On allowing for long-wavelength deformability of the background, the ensuing appearance of a volume change on freezing into the bcc structure is accompanied by reduced stability of the fluid phase and by an increase in the entropy of melting. Freezing of alkali metals into the bcc structure is next evaluated, taking their ionic pair structure as that of an ionic plasma reference fluid screened by conduction electrons and asking that the correct ionic coupling strength at liquid-solid coexistence should be approximately reproduced. The ensuring values of the volume and entropy changes across the phase transition, as estimated from the theory by two alternative routes, are in reasonable agreement with experiment. The order parameters of the phase transition, excepting the (200) one, conform rather closely to a Gaussian behaviour and yield a Lindemann ratio in reasonable agreement with the empirical value for melting of bcc crystals. It is suggested that ionic ordering at the (200) star in the metal may be (i) assisted by medium range ordering in the conduction electrons, as indicated by differences in X-ray and neutron diffraction intensities from the liquid, and/or (ii) quite small in the hot bcc solid. Such a possible premelting behaviour of bcc metals should be worth testing experimentally by diffraction. (author). 48 refs, 1 fig., 1 tab

  17. Response of seasonal soil freeze depth to climate change across China

    Science.gov (United States)

    Peng, Xiaoqing; Zhang, Tingjun; Frauenfeld, Oliver W.; Wang, Kang; Cao, Bin; Zhong, Xinyue; Su, Hang; Mu, Cuicui

    2017-05-01

    The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of -0.18 ± 0.03 cm yr-1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967-2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr-1 in most parts of China during 1950-2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze-thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

  18. CONSIDERA TIONS OF ICE MORPHOLOGY AND DRIVING FORCES IN FREEZE CONCENTRATION

    OpenAIRE

    PETZOLD MALDONADO, GUILLERMO

    2013-01-01

    Ice rnorphology (size and shape) influence decisively in sensory appreciation, texture and quality of rnany frozen foods. Ice rnorphology is also irnportant in sorne technological processes such as freeze drying and freeze concentration, which influences the efficiency ofthese processes. The overall objective of this thesis was to increase our knowledge about the control on rnorphology of the ice phase in freezing food and related processes such as freeze concentration. Freezin...

  19. Cryogenic freezing of fresh date fruits for quality preservation during frozen storage

    Directory of Open Access Journals (Sweden)

    Abdullah Alhamdan

    2018-01-01

    Full Text Available Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage. These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi at Khalal maturity stage. Fresh date fruits (cv. Barhi at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at −20 °C and −40 °C for the conventional and cryogenic freezing, respectively. Color values, textural properties (hardness, elasticity, chewiness and resilience, and nutrition attributes (enzymes and sugars for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

  20. Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

    NARCIS (Netherlands)

    Mazzeo, Teresa; Paciulli, Maria; Chiavaro, Emma; Visconti, Attilio; Fogliano, Vincenzo; Ganino, Tommaso; Pellegrini, Nicoletta

    2015-01-01

    In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content

  1. Gelatin-Filtered Consomme: A Practical Demonstration of the Freezing and Thawing Processes

    Science.gov (United States)

    Lahne, Jacob B.; Schmidt, Shelly J.

    2010-01-01

    Freezing is a key food processing and preservation technique widely used in the food industry. Application of best freezing and storage practices extends the shelf-life of foods for several months, while retaining much of the original quality of the fresh food. During freezing, as well as its counterpart process, thawing, a number of critical…

  2. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, I.; Roelofs, K.; Stins, J.F.; Jongedijk, R.A.; Hagenaars, M.A.

    2017-01-01

    Besides fight and flight responses, animals and humans may respond to threat with freezing, an adaptive response characterized by bradycardia and physical immobility. Risk assessment is enhanced during freezing to promote optimal decision-making. Indeed, healthy participants showed freezing-like

  3. Reduced early growing season freezing resistance in alpine treeline plants under elevated atmospheric CO2.

    NARCIS (Netherlands)

    Martin, M.; Gavazov, K.S.; Körner, S.; Rixen, C.

    2010-01-01

    The frequency of freezing events during the early growing season and the vulnerability to freezing of plants in European high-altitude environments could increase under future atmospheric and climate change. We tested early growing season freezing sensitivity in 10 species, from four plant

  4. The impact of freeze-drying on microstructure and rehydration properties of carrot

    NARCIS (Netherlands)

    Voda, A.; Homan, N.; Witek, M.; Duijster, A.; Dalen, van G.; Sman, van der R.G.M.; Nijsse, J.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.

    2012-01-01

    The impact of freeze-drying, blanching and freezing rate pre-treatments on the microstructure and on the rehydration properties of winter carrots were studied by µCT, SEM, MRI and NMR techniques. The freezing rate determines the size of ice crystals being formed that leave pores upon drying. Their

  5. Sintering of a freeze-dried 10 mol% Y2O3-stabilized zirconia

    International Nuclear Information System (INIS)

    Rakotoson, A.; Paulus, M.

    1983-01-01

    After presenting the results of freeze drying a sulfate solution, the authors describe a preparation process in which the freeze-drying technique by addition of a suspension of stabilized zirconia in the liquid solution before freeze-drying. This process breaks the polymeric chains, increases the green density of the compact, and decreases the sintering temperature. The mechanisms involved are discussed

  6. Sensory and physico-chemical characteristics of desserts prepared with egg products processed by freeze and spray drying

    Directory of Open Access Journals (Sweden)

    Marcelo Nunes de Jesús

    2013-09-01

    Full Text Available In this work, three freeze-dried (FD egg products (whole egg (WE, egg yolk (EY and egg white (EW were obtained and the acceptability of confections prepared with each was evaluated. Sensory analyses for confections were performed by hedonic testing with fifty panelists in each evaluation. The studied confections were: Condensed Milk Pudding (P, Quindim (Q and Meringue (M. The results obtained for confections made with FD egg products were compared with the achieved through other formulations of the same desserts made with fresh (F or spray-dried (SD egg products. The sensory analysis results for confections made with FD egg products showed good acceptance by panelists. A principal component analysis of the sensory evaluation data was carried out to identify similarities between the different egg products. The PCA supported the conclusion that FD egg products can substitute their fresh and SD counterparts in dessert formulations with good acceptability while keeping the advantages conferred by the freeze-drying method.

  7. Effect of freezing conditions on β-Tricalcium Phosphate /Camphene scaffold with micro sized particles fabricated by freeze casting.

    Science.gov (United States)

    Singh, Gurdev; Soundarapandian, S

    2018-03-01

    The long standing need of the implant manufacturing industries is to fabricate multi-matrix, customized porous scaffold as cost-effectively. In recent years, freeze casting has shown greater opportunity in the fabrication of porous scaffolds (tricalcium phosphate, hydroxyapatite, bioglass, alumina, etc.) such as at ease and good control over pore size, porosity, a range of materials and economic feasibility. In particular, tricalcium phosphate (TCP) has proved as it possesses good biocompatible (osteoinduction, osteoconduction, etc.) and biodegradability hence beta-tricalcium phosphate (β-TCP, particle size of 10µm) was used as base material and camphene was used as a freezing vehicle in this study. Both freezing conditions such as constant freezing temperature (CFT) and constant freezing rate (CFR) were used for six different conditional samples (CFT: 30, 35 and 40vol% solid loading; similarly CFR: 30, 35 and 40vol% solid loading) to study and understand the effect of various properties (pore size, porosity and compressive strength) of the freeze-cast porous scaffold. It was observed that the average size of the pore was varying linearly as from lower to higher when the solid loading was varying higher to lower. With the help of scanning electron micrographs (SEM), it was observed that the average size of pore during CFR (9.7/ 6.5/ 4.9µm) was comparatively higher than the process of CFT (6.0/ 4.8/ 2.6µm) with respect to the same solid loading (30/ 35/ 40vol%) conditions. From the Gas pycnometer analysis, it was found that the porosity in both freezing conditions (CFT, CFR) were almost near values such as 32.8% and 28.5%. Further to be observed that with the increase in solid loading, the total porosity value has decreased due to the reduction in the concentration of the freezing vehicle. Hence, the freezing vehicle was found as responsible for the formation of appropriate size and orientation of pores during freeze casting. The compressive strength (CS

  8. Applying Freeze Technology for Characterisation of Liquids, Sludge and Sediment

    International Nuclear Information System (INIS)

    Eriksson, Jens; Foster, Adam; Lindberg, Maria

    2016-01-01

    Full text of publication follows: Contaminated solids below a water table or solids in a water saturated environment can be major cost drivers and have a massive impact on the overall schedule and scope for a decommissioning project if not managed properly. One well recognized key activity in the preparation for decommissioning is to perform a proper characterisation covering all objects and areas which have been affected or potentially affected by contamination. Characterization of potentially contaminated material located below water or in water saturated environments can be difficult to perform accurately. Furthermore, traditional sampling techniques typically result in the disturbance or spreading of the contamination during sample collection. Sampling programs should be done in such a way that the radioactivity is contained (to avoid further spread of contamination), and in a way that the risk for cross contamination is minimised. Studsvik's Freeze Technology has been used to develop the necessary sampling techniques to meet these objectives. This technology is proven and frequently used for environmental characterization and remediation applications. The design of the sampling tools for radiological characterisation allows for samples to be taken at specific depths and at specific locations within the contaminated area without disturbing the contaminated material around the sample location. In addition to the sampling technique described above, a modified freeze sampling design has proven to be very useful in collecting frozen core samples that provide an accurate profile of the contamination and chemical and physical characteristics of the sediment or sludge as a function of depth into the sludge or sediment. Ultimately, this technique is used to develop a 3-D map of the physical characteristics and the chemical and radiological composition of the contaminated area. For many projects, this type of information will allow for a large reduction in the

  9. Biologic and synthetic skin substitutes: An overview.

    Science.gov (United States)

    Halim, Ahmad Sukari; Khoo, Teng Lye; Mohd Yussof, Shah Jumaat

    2010-09-01

    The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing.

  10. Biologic and synthetic skin substitutes: An overview

    Directory of Open Access Journals (Sweden)

    Halim Ahmad

    2010-10-01

    Full Text Available The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing.

  11. Precipitation of salts in freezing seawater and ozone depletion events: a status report

    Science.gov (United States)

    Morin, S.; Marion, G. M.; von Glasow, R.; Voisin, D.; Bouchez, J.; Savarino, J.

    2008-12-01

    In springtime, the polar marine boundary layer exhibits drastic ozone depletion events (ODEs), associated with elevated bromine oxide (BrO) mixing ratios. The current interpretation of this peculiar chemistry requires the existence of acid and bromide-enriched surfaces to heterogeneously promote and sustain ODEs. Sander et al. (2006) have proposed that calcium carbonate (CaCO3) precipitation in any seawater-derived medium could potentially decrease its alkalinity, making it easier for atmospheric acids such as HNO3 and H2SO4 to acidify it. We performed simulations using the state-of-the-art FREZCHEM model, capable of handling the thermodynamics of concentrated electrolyte solutions, to try to reproduce their results, and found that when ikaite (CaCO3·6H2O) rather than calcite (CaCO3) precipitates, there is no such effect on alkalinity. Given that ikaite has recently been identified in Antarctic brines (Dieckmann et al., 2008), our results show that great caution should be exercised when using the results of Sander et al. (2006), and reveal the urgent need of laboratory investigations on the actual link(s) between bromine activation and the pH of the surfaces on which it is supposed to take place at subzero temperature. In addition, the evolution of the Cl/Br ratio in the brine during freezing was computed using FREZCHEM, taking into account Br substitutions in Cl-containing salts.

  12. Summer freezing resistance: a critical filter for plant community assemblies in Mediterranean high mountains

    Directory of Open Access Journals (Sweden)

    David Sánchez Pescador

    2016-02-01

    Full Text Available Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain by measuring their ice nucleation temperature, freezing point (FP, and low-temperature damage (LT50, as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance. The community response to freezing was estimated for each plot as community weighted means (CWMs and functional diversity, and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content, and seed mass. There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the functional diversity of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only the leaf dry matter content correlated negatively with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower functional diversity of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to

  13. Freeze Tolerance of Seed-Producing Turf Bermudagrasses.

    Science.gov (United States)

    Anderson, Jeffrey A.; Taliaferro, Charles M.

    2002-01-01

    Bermudagrass, Cynodon dactylon (L.) Pers., suffers periodic severe winter-kill throughout much of its area of use in the contiguous USA. A research goal is to increase freeze tolerance in cultivars to lessen the risk of such damage. An identified research need is for Cynodon germplasm resources to be characterized for freeze tolerance and hybridization potential. Accordingly, the objective of this research was to characterize the relative freeze tolerance of selected fertile bermudagrass plants. Nine tetraploid (2n = 4x = 36) C. dactylon and two triploid (2n = 3x = 27) hybrid (C. dactylon x C. transvaalensis Burtt Davy) clonal plants (standards) were evaluated in two experiments. Plants were propagated clonally and established in Cone-tainers (Ray Leach Cone-tainer Nursery, Canby, OR) for about 10 wk. Acclimation took place for 4 wk in controlled environment chambers at 8/2 degrees C (day/night) temperatures with a 10-h photoperiod. Following acclimation, Cone-tainers were placed into a freeze chamber and cooled rapidly to -2 degrees C, induced to freeze with ice chips, then held overnight at -2 degrees C. The freeze chamber was then programmed to cool linearly at 1 degrees C per hour. For each cultivar, three Cone-tainers were removed at each test temperature. Following thawing, Cone-tainers were transferred to a greenhouse and regrowth was evaluated visually. Nonlinear regression was used to estimate T(mid), which corresponded to the midpoint of the sigmoidal response curve of survival vs temperature. Within experiment one, Tifgreen (T(mid) = -7.2 degrees C) was significantly less cold hardy than Quickstand (-9.0 degrees C), A-12204 (-9.2 degrees C), Midiron (-9.9 degrees C), and A-12195 (-10.5 degrees C). A-12195 was significantly hardier than all genotypes except Midiron. In the second experiment, Arizona Common (-6.6 degrees C), Tifgreen (-7.1 degrees C), and A-12205 (-7.1 degrees C) were less hardy than A-9959 (-8.7 degrees C), A-12156 (-8.9 degrees C), A

  14. Analytical solution and numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe

    Science.gov (United States)

    Cai, Haibing; Xu, Liuxun; Yang, Yugui; Li, Longqi

    2018-05-01

    Artificial liquid nitrogen freezing technology is widely used in urban underground engineering due to its technical advantages, such as simple freezing system, high freezing speed, low freezing temperature, high strength of frozen soil, and absence of pollution. However, technical difficulties such as undefined range of liquid nitrogen freezing and thickness of frozen wall gradually emerge during the application process. Thus, the analytical solution of the freezing-temperature field of a single pipe is established considering the freezing temperature of soil and the constant temperature of freezing pipe wall. This solution is then applied in a liquid nitrogen freezing project. Calculation results show that the radius of freezing front of liquid nitrogen is proportional to the square root of freezing time. The radius of the freezing front also decreases with decreased the freezing temperature, and the temperature gradient of soil decreases with increased distance from the freezing pipe. The radius of cooling zone in the unfrozen area is approximately four times the radius of the freezing front. Meanwhile, the numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe is conducted using the Abaqus finite-element program. Results show that the numerical simulation of soil temperature distribution law well agrees with the analytical solution, further verifies the reliability of the established analytical solution of the liquid nitrogen freezing-temperature field of a single pipe.

  15. Some quality attributes of low fat ice cream substituted with hulless barley flour and barley ß-glucan.

    Science.gov (United States)

    Abdel-Haleem, Amal M H; Awad, R A

    2015-10-01

    The purpose of this paper is to investigate some quality attributes of low fat ice cream (LFIC) substituted with hulless barley flour (HBF) and barley ß-glucan (BBG). The methodology included in this paper is based on adding HBF (1, 2, 3 and 4 %) as a partial substitution of skim milk powder (SMP) and BBG (0.40 %) as a complete substitution of carboxy methyl cellulose (CMC). All mixes and resultant ice cream samples were evaluated for their physicochemical properties as well as the sensory quality attributes.The results indicated that substitution of SMP with HBF significantly increased total solids (TS), fat and crude fiber, while crude protein and ash significantly decreased in ice cream mixes. BBG exhibited the same manner of control. Specific gravity was gradually increased with adding HBFand BBG in the mixes and therefore the overrun percent was significantly changed in the resultant ice cream. Adding HBF in ice cream formula led to significant decrease in acidity with higher freezing point and the product showed higher ability to meltdown. BBG treatment showed the same trend of control. Values of flow time and viscosity significantly increased with increasing HBF in the ice cream mixes, but these values significantly decreased in BBG mix. The time required to freeze ice cream mixes was decreased with increasing the ratio of HBF but, increased in BBG treatment. The substitution of SMP with 1 and 2 % HBF significantly (P ≤ 0.05) enhanced sensory attributes of ice cream samples. While, BBG treatment achieved mild score and acceptability.

  16. Computational study of cation substitutions in apatites

    International Nuclear Information System (INIS)

    Tamm, Toomas; Peld, Merike

    2006-01-01

    Density-functional theory plane-wave modeling of fluor- and hydroxyapatites has been performed, where one or two calcium ions per unit cell were replaced with cadmium or zinc cations. It was found that cadmium ions favor Ca(1) positions in fluorapatites and Ca(2) positions in hydroxyapatites, in agreement with experiment. A similar pattern is predicted for zinc substitutions. In the doubly substituted cases, where only hydroxyapatites were modeled, a preference for the substituting ions to be located in Ca(2) position was also observed. Displacement of the hydroxide ions from their symmetrical positions on the hexagonal axis can be used to explain the preferred configurations of substituting ions around the axis. -- Deformation of the hydroxide ion chain due to substitutions around the ion channel in substituted hydroxyapatites

  17. The Morishima Gross elasticity of substitution

    OpenAIRE

    Blackorby, Charles; Primont, Daniel; Russell, R. Robert

    2007-01-01

    We show that the Hotelling-Lau elasticity of substitution, an extension of the Allen-Uzawa elasticity to allow for optimal output-quantity (or utility) responses to changes in factor prices, inherits all of the failings of the Allen-Uzawa elasticity identified by Blackorby and Russell [1989 AER]. An analogous extension of the Morishima elasticity of substitution to allow for output quantity changes preserves the salient properties of the original Hicksian notion of elasticity of substitution.

  18. Optimization Of Freeze-Dried Starter For Yogurt By Full Factorial Experimental Design

    Directory of Open Access Journals (Sweden)

    Chen He

    2015-12-01

    Full Text Available With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB and Streptococcus thermophilus (ST, but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showed as following: the freeze-drying protective agents or anti-freeze factors could enhanced survival rate of LB and ST; the freeze-dried LB and ST powders containing both of anti-freeze factors and freeze-drying protective agents had higher viable count and freeze-drying survival rate that were 84.7% and 79.7% respectively; In terms of fermentation performance, the best group of freeze-dried starter for yogurt was the compound of LB3 and ST2.

  19. Effects of Pressure-shift Freezing on the Structural and Physical Properties of Gelatin Hydrogel Matrices

    Science.gov (United States)

    Kim, Byeongsoo; Gil, Hyung Bae; Min, Sang-Gi; Lee, Si-Kyung; Choi, Mi-Jung

    2014-01-01

    This study investigates the effects of the gelatin concentration (10-40%, w/v), freezing temperatures (from -20℃ to -50℃) and freezing methods on the structural and physical properties of gelatin matrices. To freeze gelatin, the pressure-shift freezing (PSF) is being applied at 0.1 (under atmospheric control), 50 and 100 MPa, respectively. The freezing point of gelatin solutions decrease with increasing gelatin concentrations, from -0.2℃ (10% gelatin) to -6.7℃ (40% gelatin), while the extent of supercooling did not show any specific trends. The rheological properties of the gelatin indicate that both the storage (G') and loss (G") moduli were steady in the strain amplitude range of 0.1-10%. To characterize gelatin matrices formed by the various freezing methods, the ice crystal sizes which were being determined by the scanning electron microscopy (SEM) are affected by the gelatin concentrations. The ice crystal sizes are affected by gelatin concentrations and freezing temperature, while the size distributions of ice crystals depend on the freezing methods. Smaller ice crystals are being formed with PSF rather than under the atmospheric control where the freezing temperature is above -40℃. Thus, the results of this study indicate that the PSF processing at a very low freezing temperature (-50℃) offers a potential advantage over commercial atmospheric freezing points for the formation of small ice crystals. PMID:26760743

  20. Effect of freeze/thaw cycles on several biomarkers in urine from patients with kidney disease.

    Science.gov (United States)

    Zhang, Yinan; Luo, Yi; Lu, Huijuan; Wang, Niansong; Shen, Yixie; Chen, Ruihua; Fang, Pingyan; Yu, Hong; Wang, Congrong; Jia, Weiping

    2015-04-01

    Urine samples were collected from eleven randomly selected patients with kidney disease, including diabetic nephropathy, chronic nephritis, and nephritic syndrome. Urine samples were treated with one of four protocols for freezing and thawing: freeze directly and thaw directly; freeze directly and thaw by temperature gradient; freeze by temperature gradient and thaw directly; and freeze by temperature gradient and thaw by temperature gradient. After one to six freeze/thaw cycles at -20°C or -80°C, different biomarkers showed differential stabilities. The concentrations of total protein, calcium, and potassium did not change significantly after five freeze/thaw cycles at either -20°C or -80°C. Albumin could only sustain three freeze/thaw cycles at -20°C before it started to degrade. We recommend that urine be stored at -80°C as albumin and the organic ions could sustain five and six freeze/thaw cycles, respectively, using the simple "direct freeze and direct thaw" protocol. Furthermore, in most cases, gradient freeze/thaw cycles are not necessary for urine sample storage.

  1. DSC and TMA studies on freezing and thawing gelation of galactomannan polysaccharide

    International Nuclear Information System (INIS)

    Iijima, Mika; Hatakeyama, Tatsuko; Hatakeyama, Hyoe

    2012-01-01

    Research highlights: ► Locust bean gum forms hydrogels by freezing and thawing. ► Syneresis was observed when freezing and thawing cycle (n) increased. ► Dynamic Young's modulus increased with increasing n. ► Non-freezing water content restrained by hydrogels decreased with increasing n. ► Strong gel with densely packed network structure formed with increasing n. - Abstract: Among various kinds of polysaccharides known to form hydrogels, locust bean gum (LBG) consisting of a mannose backbone and galactose side chains has unique characteristics, since LBG forms hydrogels by freezing and thawing. In this study, effect of thermal history on gelation was investigated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). Gel/sol ratio calculated by weighing method was found to be affected by sol concentration, freezing rate and the number of freezing and thawing cycle (n). Once LBG hydrogels are formed, they are thermally stable, although syneresis was observed when n increased. Dynamic Young's modulus (E′) of hydrogels measured by TMA in water increased with increasing n and decreasing freezing rate. Non-freezing water calculated from DSC melting peak of ice in the gel decreased with increasing n and decreasing freezing rate. Morphological observation of freeze-dried gels was carried out by scanning electron microscopy (SEM). The above results indicate that weak hydrogel having large molecular network structure transformed into strong gel with densely packed network structure by increasing n and decreasing freezing rate.

  2. Freezing and low temperature photoinhibition tolerance in cultivated potato and potato hybrids

    Directory of Open Access Journals (Sweden)

    M.M. SEPPÄNEN

    2008-12-01

    Full Text Available Four Solanum tuberosum L. cultivars (Nicola, Pito, Puikula, Timo and somatic hybrids between freezing tolerant S. commersonii and freezing sensitive S. tuberosum were evaluated for their tolerance to freezing and low temperature photoinhibition. Cellular freezing tolerance was studied using ion leakage tests and the sensitivity of the photosynthetic apparatus to freezing and high light intensity stress by measuring changes in chlorophyll fluorescence (FV/FM and oxygen evolution. Exposure to high light intensities after freezing stress increased frost injury significantly in all genotypes studied. Compared with S. tuberosum cultivars, the hybrids were more tolerant both of freezing and intense light stresses. In field experiments the mechanism of frost injury varied according to the severity of night frosts. During night frosts in 1999, the temperature inside the potato canopy was significantly higher than at ground level, and did not fall below the lethal temperature for potato cultivars (from -2.5 to -3.0°C. As a result, frost injury developed slowly, indicating that damage occurred to the photosynthetic apparatus. However, as the temperature at ground level and inside the canopy fell below -4°C, cellular freezing occurred and the canopy was rapidly destroyed. This suggests that in the field visual frost damage can follow from freezing or non-freezing temperatures accompanied with high light intensity. Therefore, in an attempt to improve low temperature tolerance in potato, it is important to increase tolerance to both freezing and chilling stresses.

  3. Contact freezing of supercooled cloud droplets on collision with mineral dust particles: effect of particle size

    Science.gov (United States)

    Hoffmann, Nadine; Duft, Denis; Kiselev, Alexei; Leisner, Thomas

    2013-04-01

    The contact freezing of supercooled cloud droplets is one of the potentially important and the least investigated heterogeneous mechanism of ice formation in the tropospheric clouds [1]. On the time scales of cloud lifetime the freezing of supercooled water droplets via contact mechanism may occur at higher temperature compared to the same IN immersed in the droplet. However, the laboratory experiments of contact freezing are very challenging due to the number of factors affecting the probability of ice formation. In our experiment we study single water droplets freely levitated in the laminar flow of mineral dust particles acting as the contact freezing nuclei. By repeating the freezing experiment sufficient number of times we are able to reproduce statistical freezing behavior of large ensembles of supercooled droplets and measure the average rate of freezing events. We show that the rate of freezing at given temperature is governed only by the rate of droplet -particle collision and by the properties of the contact ice nuclei. In this contribution we investigate the relationship between the freezing probability and the size of mineral dust particle (represented by illite) and show that their IN efficiency scales with the particle size. Based on this observation, we discuss the similarity between the freezing of supercooled water droplets in immersion and contact modes and possible mechanisms of apparent enhancement of the contact freezing efficiency. [1] - K.C. Young, The role of contact nucleation in ice phase initiation in clouds, Journal of the Atmospheric Sciences 31, 1974

  4. Freezing in the presence of disorder: a lattice study

    International Nuclear Information System (INIS)

    Schmidt, Matthias; Lafuente, Luis; Cuesta, Jose A

    2003-01-01

    We investigate the freezing transition in a two-dimensional lattice model of annealed hard squares that are subject to the influence of randomly placed quenched particles of the same size. The latter model is a porous medium. By combining two recent density functional approaches we arrive at a theory for quenched-annealed lattice fluids that treats the quenched particles on the level of their one-body density distribution. We show that this approach yields thermodynamics that compare well with results from treating matrix realizations explicitly and performing subsequent averaging over the disorder. The freezing transition from a fluid to a columnar phase is found to be continuous. On increasing matrix density it shifts towards close packing and vanishes beyond a threshold matrix density

  5. Heat and Mass Transfer Model in Freeze-Dried Medium

    Science.gov (United States)

    Alfat, Sayahdin; Purqon, Acep

    2017-07-01

    There are big problems in agriculture sector every year. One of the major problems is abundance of agricultural product during the peak of harvest season that is not matched by an increase in demand of agricultural product by consumers, this causes a wasted agricultural products. Alternative way was food preservation by freeze dried method. This method was already using heat transfer through conduction and convection to reduce water quality in the food. The main objective of this research was to design a model heat and mass transfer in freeze-dried medium. We had two steps in this research, the first step was design of medium as the heat injection site and the second was simulate heat and mass transfer of the product. During simulation process, we use physical property of some agriculture product. The result will show how temperature and moisture distribution every second. The method of research use finite element method (FEM) and will be illustrated in three dimensional.

  6. Preventing freezing of condensate inside tubes of air cooled condenser

    International Nuclear Information System (INIS)

    Joo, Jeong A; Hwang, In Hwan; Lee, Dong Hwan; Cho, Young Il

    2012-01-01

    An air cooled condenser is a device that is used for converting steam into condensate by using ambient air. The air cooled condenser is prone to suffer from a serious explosion when the condensate inside the tubes of a heat exchanger is frozen; in particular, tubes can break during winter. This is primarily due to the structural problem of the tube outlet of an existing conventional air cooled condenser system, which causes the backflow of residual steam and noncondensable gases. To solve the backflow problem in such condensers, such a system was simulated and a new system was designed and evaluated in this study. The experimental results using the simulated condenser showed the occurrence of freezing because of the backflow inside the tube. On the other hand, no backflow and freezing occurred in the advanced new condenser, and efficient heat exchange occurred

  7. Superchilling of muscle foods: Potential alternative for chilling and freezing.

    Science.gov (United States)

    Banerjee, Rituparna; Maheswarappa, Naveena Basappa

    2017-12-05

    Superchilling is an attractive technique for preservation of muscle foods which freezes part of the water and insulate the food products from temperature fluctuations thereby enhancing the shelf-life during storage, transportation and retailing. Superchilling process synergistically improves the product shelf-life when used in combination with vacuum or modified atmospheric packaging. The shelf-life of muscle foods was reported to be increased by 1.5 to 4.0 times relative to traditional chilling technique. Advantages of superchilling and its ability to maintain the freshness of muscle foods over freezing has been discussed and its potential for Industrial application is highlighted. Present review also unravel the mechanistic bases for ice-crystal formation during superchilling and measures to ameliorate the drip loss. The future challenges especially automation in superchilling process for large scale Industrial application is presented.

  8. Encapsulation of black carrot juice using spray and freeze drying.

    Science.gov (United States)

    Murali, S; Kar, Abhijit; Mohapatra, Debabandya; Kalia, Pritam

    2015-12-01

    Black carrot juice extracted using pectinase enzyme was encapsulated in three different carrier materials (maltodextrin 20DE, gum arabic and tapioca starch) using spray drying at four inlet temperatures (150, 175, 200 and 225 ℃) and freeze drying at a constant temperature of - 53 ℃ and vacuum of 0.22-0.11 mbar with the constant feed mixture. The products were analyzed for total anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and total colour change. For both the drying methods followed in this study, maltodextrin 20DE as the carrier material has proven to be better in retaining maximum anthocyanin and antioxidant activity compared to gum arabic and tapioca starch. The best spray dried product, was obtained at 150 ℃. The most acceptable was the freeze dried product with maximum anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and colour change. © The Author(s) 2014.

  9. Five-dimensional imaging of freezing emulsions with solute effects.

    Science.gov (United States)

    Dedovets, Dmytro; Monteux, Cécile; Deville, Sylvain

    2018-04-20

    The interaction of objects with a moving solidification front is a common feature of many industrial and natural processes such as metal processing, the growth of single crystals, the cryopreservation of cells, or the formation of sea ice. Interaction of solidification fronts with objects leads to different outcomes, from total rejection of the objects to their complete engulfment. We imaged the freezing of emulsions in five dimensions (space, time, and solute concentration) with confocal microscopy. We showed that the solute induces long-range interactions that determine the solidification microstructure. The local increase of solute concentration enhances premelting, which controls the engulfment of droplets by the front and the evolution of grain boundaries. Freezing emulsions may be a good analog of many solidification systems where objects interact with a solidification interface. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  10. Isolation of mutations affecting the development of freezing tolerance in Arabidopsis thaliana (L.) Heynh.

    Science.gov (United States)

    Warren, G; McKown, R; Marin, A L; Teutonico, R

    1996-08-01

    We screened for mutations deleterious to the freezing tolerance of Arabidopsis thaliana (L.) Heynh. ecotype Columbia. Tolerance was assayed by the vigor and regrowth of intact plants after cold acclimation and freezing. From a chemically mutagenized population, we obtained 13 lines of mutants with highly penetrant phenotypes. In 5 of these, freezing sensitivity was attributable to chilling injury sustained during cold acclimation, but in the remaining 8 lines, the absence of injury prior to freezing suggested that they were affected specifically in the development of freezing tolerance. In backcrosses, freezing sensitivity from each line segregated as a single nuclear mutation. Complementation tests indicated that the 8 lines contained mutations in 7 different genes. The mutants' freezing sensitivity was also detectable in the leakage of electrolytes from frozen leaves. However, 1 mutant line that displayed a strong phenotype at the whole-plant level showed a relatively weak phenotype by the electrolyte leakage assay.

  11. Statistical Physics of Complex Substitutive Systems

    Science.gov (United States)

    Jin, Qing

    Diffusion processes are central to human interactions. Despite extensive studies that span multiple disciplines, our knowledge is limited to spreading processes in non-substitutive systems. Yet, a considerable number of ideas, products, and behaviors spread by substitution; to adopt a new one, agents must give up an existing one. This captures the spread of scientific constructs--forcing scientists to choose, for example, a deterministic or probabilistic worldview, as well as the adoption of durable items, such as mobile phones, cars, or homes. In this dissertation, I develop a statistical physics framework to describe, quantify, and understand substitutive systems. By empirically exploring three collected high-resolution datasets pertaining to such systems, I build a mechanistic model describing substitutions, which not only analytically predicts the universal macroscopic phenomenon discovered in the collected datasets, but also accurately captures the trajectories of individual items in a complex substitutive system, demonstrating a high degree of regularity and universality in substitutive systems. I also discuss the origins and insights of the parameters in the substitution model and possible generalization form of the mathematical framework. The systematical study of substitutive systems presented in this dissertation could potentially guide the understanding and prediction of all spreading phenomena driven by substitutions, from electric cars to scientific paradigms, and from renewable energy to new healthy habits.

  12. Synthesis and structural evaluation of freeze-cast porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  13. Freezing and thawing resistance of aerial lime mortar with metakaolin\

    Czech Academy of Sciences Publication Activity Database

    Nunes, Cristiana Lara; Slížková, Zuzana

    2016-01-01

    Roč. 114, July (2016), s. 896-905 ISSN 0950-0618 R&D Projects: GA ČR(CZ) GBP105/12/G059 Institutional support: RVO:68378297 Keywords : freeze-thaw * lime * metakaolin * linseed oil * mortar * water-repellency Subject RIV: JN - Civil Engineering Impact factor: 3.169, year: 2016 http://www.sciencedirect.com/science/article/pii/S0950061816305645

  14. Contrasting continuous emission versus freeze-out via HBT

    Energy Technology Data Exchange (ETDEWEB)

    Padula, S.S. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Grassi, F.; Hama, Y.; Socolowski Junior, O. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    2001-07-01

    The effect of continuous emission hypothesis on the two-pion Bose-Einstein correlation is discussed and compared with the corresponding results based on the usual freeze-out ansatz. Sizable differences in the correlation function are observed when comparing these two scenarios of the decoupling process. They could lead to entirely different interpretation of properties of the hot matter formed in high-energy heavy-ion collisions. (author)

  15. Contrasting continuous emission versus freeze-out via HBT

    International Nuclear Information System (INIS)

    Padula, S.S.; Grassi, F.; Hama, Y.; Socolowski Junior, O.

    2001-01-01

    The effect of continuous emission hypothesis on the two-pion Bose-Einstein correlation is discussed and compared with the corresponding results based on the usual freeze-out ansatz. Sizable differences in the correlation function are observed when comparing these two scenarios of the decoupling process. They could lead to entirely different interpretation of properties of the hot matter formed in high-energy heavy-ion collisions. (author)

  16. Accelerated redox reaction between chromate and phenolic pollutants during freezing.

    Science.gov (United States)

    Ju, Jinjung; Kim, Jaesung; Vetráková, Ľubica; Seo, Jiwon; Heger, Dominik; Lee, Changha; Yoon, Ho-Il; Kim, Kitae; Kim, Jungwon

    2017-05-05

    The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at -20°C) was compared with the corresponding reaction in water (i.e., at 25°C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV-vis absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Freeze-out conditions in ultrarelativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu, N.

    1996-01-01

    The authors present recent results on single particle transverse momentum distributions of pions, kaons, and protons, measured in CERN Experiment NA44, of 200A·FeV/c S+S and 158A·GeV/c Pb+Pb central collisions. By comparing these data with thermal and transport models, freeze-out parameters like the temperature T fo and the chemical potentials (μ q , μ s ) are extracted and discussed

  18. Substitution dynamical systems spectral analysis

    CERN Document Server

    Queffélec, Martine

    2010-01-01

    This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

  19. Controversial issues of maternity substitution

    Directory of Open Access Journals (Sweden)

    Andy Pușcă

    2009-06-01

    Full Text Available Substitute maternity consists in a woman carrying a pregnancy (the implant of an embryo, at therequest of a sterile couple, most of the times in exchange of a sum of money, with her commitment tounconditionally give away the newborn after birth to the couple she concluded the agreement with. Manycontroversies emerged in what concerns the contract between the sterile couple and the carrying mother,especially when this contract is by onerous title, which happens in most of the cases. In that a civil contract? Is ita sales contract for the child? Is it a contract to provide services? Is it body marketing? Between total prohibitionand excessive liberalism, the middle way, which is the regulation according to ethical religious, cultural andsocial norms of each community, represents a realistic solution.

  20. Photoelectron Spectroscopy of Substituted Phenylnitrenes

    Science.gov (United States)

    Wijeratne, Neloni R.; Da Fonte, Maria; Wenthold, Paul G.

    2009-06-01

    Nitrenes are unusual molecular structures with unfilled electronic valences that are isoelectronic with carbenes. Although, both can be generated by either thermal or photochemical decomposition of appropriate precursors they usually exhibit different reactivities. In this work, we carry out spectroscopic studies of substituted phenylnitrene to determine how the introduction of substituents will affect the reactivity and its thermochemical properties. All studies were carried out by using the newly constructed time-of-flight negative ion photoelectron spectrometer (NIPES) at Purdue University. The 355 nm photoelectron spectra of the o-, m-, and p-chlorophenyl nitrene anions are fairly similar to that measured for phenylnitrene anion. All spectra show low energy triplet state and a high energy singlet state. The singlet state for the meta isomer is well-resolved, with a well defined origin and observable vibrational structure. Whereas the singlet states for the ortho and para isomers have lower energy onsets and no resolved structure. The isomeric dependence suggests that the geometry differences result from the resonance interaction between the nitrogen and the substituent. Quinoidal resonance structures are possible for the open-shell singlet states of the o- and p-chlorinated phenyl nitrenes. The advantages of this type of electronic structures for the open-shell singlet states is that the unpaired electrons can be more localized on separate atoms in the molecules, minimizing the repulsion between. Because the meta position is not in resonance with the nitrenes, substitution at that position should not affect the structure of the open-shell singlet state. The measured electron affinities (EA) of the triplet phenylnitrenes are in excellent agreement with the values predicted by electronic structure calculations. The largest EA, 1.82 eV is found for the meta isomer, with para being the smallest, 1.70 eV.

  1. Methods of human body odor sampling: the effect of freezing.

    Science.gov (United States)

    Lenochova, Pavlina; Roberts, S Craig; Havlicek, Jan

    2009-02-01

    Body odor sampling is an essential tool in human chemical ecology research. However, methodologies of individual studies vary widely in terms of sampling material, length of sampling, and sample processing. Although these differences might have a critical impact on results obtained, almost no studies test validity of current methods. Here, we focused on the effect of freezing samples between collection and use in experiments involving body odor perception. In 2 experiments, we tested whether axillary odors were perceived differently by raters when presented fresh or having been frozen and whether several freeze-thaw cycles affected sample quality. In the first experiment, samples were frozen for 2 weeks, 1 month, or 4 months. We found no differences in ratings of pleasantness, attractiveness, or masculinity between fresh and frozen samples. Similarly, almost no differences between repeatedly thawed and fresh samples were found. We found some variations in intensity; however, this was unrelated to length of storage. The second experiment tested differences between fresh samples and those frozen for 6 months. Again no differences in subjective ratings were observed. These results suggest that freezing has no significant effect on perceived odor hedonicity and that samples can be reliably used after storage for relatively long periods.

  2. Freeze-dried processing of tungsten heavy alloys

    International Nuclear Information System (INIS)

    White, G.D.; Gurwell, W.E.

    1989-06-01

    Tungsten heavy alloy powders were produced from freeze-dried aqueous solutions of ammonium metatungstate and, principally, sulfates of Ni and Fe. The freeze-dried salts were calcined and hydrogen reduced to form very fine, homogeneous, low-density, W heavy alloy powders having a coral-like structure with elements of approximately 0.1 μm in diameter. The powders yield high green strength and sinterability. Tungsten heavy alloy powders of 70%, 90%, and 96% W were prepared by freeze drying, compacted, and solid-state (SS) sintered to fully density at temperatures as low as 1200 degree C and also at conventional liquid-phase (LP) sintering temperatures. Solid-state sintered microstructures contained polygonal W grains with high contiguity; the matrix did not coat and separate the W grains to form low-contiguity, high-ductility structures. Liquid-phase sintered microstructures were very conventional in appearance, having W spheroids of low contiguity. All these materials were found to be brittle. High levels of residual S accompanied by segregation of the S to all the microstructural interfaces are principally responsible for the brittleness; problems with S could be eliminated by using Fe and Ni nitrates rather than the sulfates. 9 refs., 22 figs., 3 tabs

  3. Effects of gamma radiation on freeze-dried wheat seeds

    International Nuclear Information System (INIS)

    Ajayi, N.O.; Larsson, B.

    1975-07-01

    The effect of radiation on freeze-dried wheat seeds are reported. The response of the various parts of the seedling to radiation was found to differ from one another. There was no significant modification of the effect of radiation on the shoot and root growth, while the growth of the coleoptile was slightly reduced in the frezze-dried seeds. The change in the shoot growth-absorbed dose relationship reported by others to occur at high doses for oven-dried as compared to air-dried barley seeds was not seen for the control and freeze-dried wheat seeds. The freeze-dried seeds are believed to show only the effect of radiation without any modification due to drying as such. The dose-effect relationships may be splited into functions characterised by different radiosensitivity. The high sensitivty effect is mainly taking place within the first 40 krad of energy absorption, and the low sensitivity is dominating at higher doses. (author)

  4. Warm and cold fermionic dark matter via freeze-in

    International Nuclear Information System (INIS)

    Klasen, Michael; Yaguna, Carlos E.

    2013-01-01

    The freeze-in mechanism of dark matter production provides a simple and intriguing alternative to the WIMP paradigm. In this paper, we analyze whether freeze-in can be used to account for the dark matter in the so-called singlet fermionic model. In it, the SM is extended with only two additional fields, a singlet scalar that mixes with the Higgs boson, and the dark matter particle, a fermion assumed to be odd under a Z 2 symmetry. After numerically studying the generation of dark matter, we analyze the dependence of the relic density with respect to all the free parameters of the model. These results are then used to obtain the regions of the parameter space that are compatible with the dark matter constraint. We demonstrate that the observed dark matter abundance can be explained via freeze-in over a wide range of masses extending down to the keV range. As a result, warm and cold dark matter can be obtained in this model. It is also possible to have dark matter masses well above the unitarity bound for WIMPs

  5. Open Zinc Freezing-Point Cell Assembly and Evaluation

    Science.gov (United States)

    Žužek, V.; Batagelj, V.; Drnovšek, J.; Bojkovski, J.

    2014-07-01

    An open metal freezing-point cell design has been developed in the Laboratory of Metrology and Quality. According to our design, a zinc cell was successfully assembled. The paper presents the needed parts for the cell, the cleaning process, and sealing of the cell. The assembled cell was then evaluated by comparison with two commercial closed zinc cells of different manufacturers. The freezing plateaus of the cells were measured, and a direct cell comparison was made. It was shown that the assembled open cell performed better than the used closed cell and was close to the brand new closed cell. The nominal purity of the zinc used for the open cell was 7 N, but the freezing plateau measurement suggests a higher impurity concentration. It was assumed that the zinc was contaminated to some extent during the process of cutting as its original shape was an irregular cylinder. The uncertainty due to impurities for the assembled cell is estimated to be 0.3 mK. Furthermore, the immersion profile and the pressure coefficient were measured. Both results are close to their theoretical values.

  6. Validation of Freezing-of-Gait Monitoring Using Smartphone.

    Science.gov (United States)

    Kim, Han Byul; Lee, Hong Ji; Lee, Woong Woo; Kim, Sang Kyong; Jeon, Hyo Seon; Park, Hye Young; Shin, Chae Won; Yi, Won Jin; Jeon, Beomseok; Park, Kwang S

    2018-04-30

    Freezing of gait (FOG) is a commonly observed motor symptom for patients with Parkinson's disease (PD). The symptoms of FOG include reduced step lengths or motor blocks, even with an evident intention of walking. FOG should be monitored carefully because it not only lowers the patient's quality of life, but also significantly increases the risk of injury. In previous studies, patients had to wear several sensors on the body and another computing device was needed to run the FOG detection algorithm. Moreover, the features used in the algorithm were based on low-level and hand-crafted features. In this study, we propose a FOG detection system based on a smartphone, which can be placed in the patient's daily wear, with a novel convolutional neural network (CNN). The walking data of 32 PD patients were collected from the accelerometer and gyroscope embedded in the smartphone, located in the trouser pocket. The motion signals measured by the sensors were converted into the frequency domain and stacked into a 2D image for the CNN input. A specialized CNN model for FOG detection was determined through a validation process. We compared our performances with the results acquired by the previously reported settings. The proposed architecture discriminated the freezing events from the normal activities with an average sensitivity of 93.8% and a specificity of 90.1%. Using our methodology, the precise and continuous monitoring of freezing events with unconstrained sensing can assist patients in managing their chronic disease in daily life effectively.

  7. Dynamical Dark Matter from thermal freeze-out

    Science.gov (United States)

    Dienes, Keith R.; Fennick, Jacob; Kumar, Jason; Thomas, Brooks

    2018-03-01

    In the Dynamical Dark-Matter (DDM) framework, the dark sector comprises a large number of constituent dark particles whose individual masses, lifetimes, and cosmological abundances obey specific scaling relations with respect to each other. In particular, the most natural versions of this framework tend to require a spectrum of cosmological abundances which scale inversely with mass, so that dark-sector states with larger masses have smaller abundances. Thus far, DDM model-building has primarily relied on nonthermal mechanisms for abundance generation such as misalignment production, since these mechanisms give rise to abundances that have this property. By contrast, the simplest versions of thermal freeze-out tend to produce abundances that increase, rather than decrease, with the mass of the dark-matter component. In this paper, we demonstrate that there exist relatively simple modifications of the traditional thermal freeze-out mechanism which "flip" the resulting abundance spectrum, producing abundances that scale inversely with mass. Moreover, we demonstrate that a far broader variety of scaling relations between lifetimes, abundances, and masses can emerge through thermal freeze-out than through the nonthermal mechanisms previously considered for DDM ensembles. The results of this paper thus extend the DDM framework into the thermal domain and essentially allow us to "design" our resulting DDM ensembles at will in order to realize a rich array of resulting dark-matter phenomenologies.

  8. Freezing of a colloidal liquid subject to shear flow

    International Nuclear Information System (INIS)

    Bagchi, B.; Thirumalai, D.

    1988-01-01

    A nonequilibrium generalization of the density-functional theory of freezing is proposed to investigate the shear-induced first-order phase transition in colloidal suspensions. It is assumed that the main effect of a steady shear is to break the symmetry of the structure factor of the liquid and that for small shear rate, the phenomenon of a shear-induced order-disorder transition may be viewed as an equilibrium phase transition. The theory predicts that the effective density at which freezing takes place increases with shear rate. The solid (which is assumed to be a bcc lattice) formed upon freezing is distorted and specifically there is less order in one plane compared with the order in the other two perpendicular planes. It is shown that there exists a critical shear rate above which the colloidal liquid does not undergo a transition to an ordered (or partially ordered) state no matter how large the density is. Conversely, above the critical shear rate an initially formed bcc solid always melts into an amorphous or liquidlike state. Several of these predictions are in qualitative agreement with the light-scattering experiments of Ackerson and Clark. The limitations as well as possible extensions of the theory are also discussed

  9. Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

    Science.gov (United States)

    Berisford, Daniel F.; Birur, Gajanana C.; Miller, Jennifer R.; Sunada, Eric T.; Ganapathi, Gani B.; Stephan, Ryan; Johnson, Mark

    2011-01-01

    The digital radiator technology is one of three variable heat rejection technologies being investigated for future human-rated NASA missions. The digital radiator concept is based on a mechanically pumped fluid loop with parallel tubes carrying coolant to reject heat from the radiator surface. A series of valves actuate to start and stop fluid flow to di erent combinations of tubes, in order to vary the heat rejection capability of the radiator by a factor of 10 or more. When the flow in a particular leg is stopped, the fluid temperature drops and the fluid can freeze, causing damage or preventing flow from restarting. For this reason, the liquid in a stopped leg must be partially or fully evacuated upon shutdown. One of the challenges facing fluid evacuation from closed tubes arises from the vapor generated during pumping to low pressure, which can cause pump cavitation and incomplete evacuation. Here we present a series of laboratory experiments demonstrating fluid evacuation techniques to overcome these challenges by applying heat and pumping to partial vacuum. Also presented are results from qualitative testing of the freezing characteristics of several different candidate fluids, which demonstrate significant di erences in freezing properties, and give insight to the evacuation process.

  10. Freeze-In dark matter with displaced signatures at colliders

    International Nuclear Information System (INIS)

    Co, Raymond T.; D’Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2015-01-01

    Dark matter, X, may be generated by new physics at the TeV scale during an early matter-dominated (MD) era that ends at temperature T R ≪ TeV. Compared to the conventional radiation-dominated (RD) results, yields from both Freeze-Out and Freeze-In processes are greatly suppressed by dilution from entropy production, making Freeze-Out less plausible while allowing successful Freeze-In with a much larger coupling strength. Freeze-In is typically dominated by the decay of a particle B of the thermal bath, B→X. For a large fraction of the relevant cosmological parameter space, the decay rate required to produce the observed dark matter abundance leads to displaced signals at LHC and future colliders, for any m X in the range keV

  11. Freeze cast porous barium titanate for enhanced piezoelectric energy harvesting

    Science.gov (United States)

    Roscow, J. I.; Zhang, Y.; Kraśny, M. J.; Lewis, R. W. C.; Taylor, J.; Bowen, C. R.

    2018-06-01

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of barium titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous barium titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast barium titanate with 45 vol.% porosity had a d 33  =  134.5 pC N‑1 compared to d 33  =  144.5 pC N‑1 for dense barium titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of barium titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N‑1 for barium titanate with 45 vol.% porosity, compared to only 1.40 pm2 N‑1 for dense barium titanate. Dense and porous barium titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous barium titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that

  12. A Determination of the Ratio of the Zinc Freezing Point to the Tin Freezing Point by Noise Thermometry

    Science.gov (United States)

    Labenski, J. R.; Tew, W. L.; Benz, S. P.; Nam, S. W.; Dresselhaus, P.

    2008-02-01

    A Johnson-noise thermometer (JNT) has been used with a quantized voltage noise source (QVNS), as a calculable reference to determine the ratio of temperatures near the Zn freezing point to those near the Sn freezing point. The temperatures are derived in a series of separate measurements comparing the synthesized noise power from the QVNS with that of Johnson noise from a known resistance. The synthesized noise power is digitally programed to match the thermal noise powers at both temperatures and provides the principle means of scaling the temperatures. This produces a relatively flat spectrum for the ratio of spectral noise densities, which is close to unity in the low-frequency limit. The data are analyzed as relative spectral ratios over the 4.8 to 450 kHz range averaged over a 3.2 kHz bandwidth. A three-parameter model is used to account for differences in time constants that are inherently temperature dependent. A drift effect of approximately -6 μK·K-1 per day is observed in the results, and an empirical correction is applied to yield a relative difference in temperature ratios of -11.5 ± 43 μK·K-1 with respect to the ratio of temperatures assigned on the International Temperature Scale of 1990 (ITS-90). When these noise thermometry results are combined with results from acoustic gas thermometry at temperatures near the Sn freezing point, a value of T - T 90 = 7 ± 30 mK for the Zn freezing point is derived.

  13. Freezing of bentonite. Experimental studies and theoretical considerations

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Martin; Karnland, Ola; Nilsson, Ulf (Clay Technology AB, Lund (Sweden))

    2010-01-15

    During its lifetime, a KBS-3 repository will be subject to various ambient temperatures. Backfilled tunnels, shafts and investigation bore holes closest to ground level will experience periods of temperature below 0 deg C. From a safety assessment perspective, it is therefore essential to understand the behavior of compacted bentonite below 0 deg C. A theoretical framework for predicting the pressure response in compacted water saturated bentonite due to temperature changes has been developed based on thermodynamics and a single pore-type. This model predicts an approximately linear temperature dependence of swelling pressure P{sub s}(w,DELTAT) = P{sub s}(w,0 deg C) + DELTAs(w)DELTAT/nu{sub clay}(w) where DELTAT denotes a temperature difference from 0 deg C, DELTAs(w) is the difference in partial molar entropy between clay water and bulk water, nu{sub clay} (w) is the partial molar volume of the clay water and w denotes the water/solid mass ratio of the clay. As bulk water changes phase at 0 deg C, DELTAs(w) has a different value dependent on whether DELTAT is negative or positive. Above 0 deg C DELTAs(w) is a small value for all relevant densities which means that the pressure response due to temperature changes is small. A further consequence of this fact is that DELTAs(w) is a large positive number below 0 deg C when the external water phase is transformed to ice. Consequently, the model predicts a large drop of swelling pressure with temperature below 0 deg C, in the order of 1.2 MPa/deg C. Specifically, the swelling pressure is zero at a certain (negative) temperature T{sub C}. T{sub C} also quantifies the freezing point of the bentonite sample under consideration, as ice formation in the bentonite does not occur until swelling pressure is lost. A large set of laboratory tests have been performed where fully water saturated samples of bentonites have been exposed to temperatures in the range -10 deg C to +25 deg C. The swelling pressure response has been

  14. Shrinkage of spray-freeze-dried microparticles of pure protein for ballistic injection by manipulation of freeze-drying cycle.

    Science.gov (United States)

    Straller, Georg; Lee, Geoffrey

    2017-10-30

    Spray-freeze-drying was used to produce shrivelled, partially-collapsed microparticles of pure proteins that may be suitable for use in a ballistic injector. Various modifications of the freeze drying cycle were examined for their effects on collapse of the pure protein microparticles. The use of annealing at a shelf temperature of up to +10°C resulted in no visible particle shrinkage. This was because of the high T g ' of the pure protein. Inclusion of trehalose or sucrose led to particle shrinkage because of the plasticizing effects of the disaccharides on the protein. Only by extending the duration of primary drying from 240 to 2745min at shelf temperatures in the range -12 to -8°C were shrivelled, wrinkled particles of bSA and bCA of reduced porosity obtained. Manipulation of the freeze-drying cycle used for SFD can therefore be used to modify particle morphology and increase particle density. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Immersion freezing of ice nucleation active protein complexes

    Directory of Open Access Journals (Sweden)

    S. Hartmann

    2013-06-01

    Full Text Available Utilising the Leipzig Aerosol Cloud Interaction Simulator (LACIS, the immersion freezing behaviour of droplet ensembles containing monodisperse particles, generated from a Snomax™ solution/suspension, was investigated. Thereto ice fractions were measured in the temperature range between −5 °C to −38 °C. Snomax™ is an industrial product applied for artificial snow production and contains Pseudomonas syringae} bacteria which have long been used as model organism for atmospheric relevant ice nucleation active (INA bacteria. The ice nucleation activity of such bacteria is controlled by INA protein complexes in their outer membrane. In our experiments, ice fractions increased steeply in the temperature range from about −6 °C to about −10 °C and then levelled off at ice fractions smaller than one. The plateau implies that not all examined droplets contained an INA protein complex. Assuming the INA protein complexes to be Poisson distributed over the investigated droplet populations, we developed the CHESS model (stoCHastic modEl of similar and poiSSon distributed ice nuclei which allows for the calculation of ice fractions as function of temperature and time for a given nucleation rate. Matching calculated and measured ice fractions, we determined and parameterised the nucleation rate of INA protein complexes exhibiting class III ice nucleation behaviour. Utilising the CHESS model, together with the determined nucleation rate, we compared predictions from the model to experimental data from the literature and found good agreement. We found that (a the heterogeneous ice nucleation rate expression quantifying the ice nucleation behaviour of the INA protein complex is capable of describing the ice nucleation behaviour observed in various experiments for both, Snomax™ and P. syringae bacteria, (b the ice nucleation rate, and its temperature dependence, seem to be very similar regardless of whether the INA protein complexes inducing ice

  16. Type Substitution for Object-Oriented Programming

    DEFF Research Database (Denmark)

    Schwartzbach, Michael Ignatieff; Palsberg, Jens

    1990-01-01

    Genericity allows the substitution of types in a class. This is usually obtained through parameterized classes, although they are inflexible since any class can be inherited but is not in itself parameterized. We suggest a new genericity mechanism, type substitution, which is a subclassing concep...

  17. Multisensory integration, sensory substitution and visual rehabilitation

    DEFF Research Database (Denmark)

    Proulx, Michael J; Ptito, Maurice; Amedi, Amir

    2014-01-01

    Sensory substitution has advanced remarkably over the past 35 years since first introduced to the scientific literature by Paul Bach-y-Rita. In this issue dedicated to his memory, we describe a collection of reviews that assess the current state of neuroscience research on sensory substitution...

  18. Educators Take Another Look at Substitutes

    Science.gov (United States)

    Zubrzycki, Jaclyn

    2012-01-01

    The mythology surrounding the substitute teacher is not a pretty one: Paper airplanes, lost learning, bullying. But as schools collect more information about teacher absenteeism and its consequences, districts and schools are exploring ways to professionalize substitute teaching--or experiment with alternative ways of coping with teacher absences.…

  19. Application of two electrical methods for the rapid assessment of freezing resistance in Salix epichloro

    Energy Technology Data Exchange (ETDEWEB)

    Tsarouhas, V.; Kenney, W.A.; Zsuffa, L. [University of Toronto, Ontario (Canada). Faculty of Forestry

    2000-09-01

    The importance of early selection of frost-resistant Salix clones makes it desirable to select a rapid and accurate screening method for assessing freezing resistance among several genotypes. Two electrical methods, stem electrical impedance to 1 and 10 khz alternating current, and electrolyte leakage of leaf tissue, were evaluated for detecting freezing resistance on three North America Salix epichloro Michx., clones after subjecting them to five different freezing temperatures (-1, -2, -3, -4, and -5 deg C). Differences in the electrical impedance to 1 and 10 kHz, and the ratio of the impedance at the two frequencies (low/high) before and after the freezing treatment (DZ{sub low}, DZ{sub high}, and DZ{sub ratio}, respectively) were estimated. Electrolyte leakage was expressed as relative conductivity (RC{sub t}) and index of injury (IDX{sub t}). Results from the two methods, obtained two days after the freezing stress, showed that both electrical methods were able to detect freezing injury in S. eriocephala. However, the electrolyte leakage method detected injury in more levels of freezing stress (-3, -4, and -5 deg C) than the impedance (-4, and -5 deg C), it assessed clonal differences in S. eriocephala freezing resistance, and it was best suited to correlate electrical methods with the visual assessed freezing injury. No significant impedance or leakage changes were found after the -1 and -2 deg C freezing temperatures. (author)

  20. Substitution between cars within the household

    DEFF Research Database (Denmark)

    De Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

    2016-01-01

    In this paper we study the demand for car kilometres in two-car households, focusing on the substitution between cars of different fuel efficiency in response to fuel price changes. We use a large sample of detailed Danish data on two-car households to estimate – for each car owned by the household...... – own and cross-price effects of increases in fuel costs per kilometre. The empirical results show that failure to capture substitution between cars within the household can result in substantial misspecification biases. Ignoring substitution, the basic model yielded fuel price elasticities of 0.......98 and 1.41 for the primary and secondary cars, respectively. Accounting for substitution effects, these figures reduce to, respectively, 0.32 and 0.45. Consistent with substitution behaviour, we find that the fuel price elasticity of fuel demand exceeds the elasticity of kilometre demands with respect...

  1. Elasticity of Substitution and Antidumping Measures

    DEFF Research Database (Denmark)

    Drud Hansen, Jørgen; Meinen, Philipp; Nielsen, Jørgen Ulff-Møller

    Abstract This paper analyzes the role of the elasticity of substitution for anti-dumping decisions across countries. In monopolistic competition models with cost heterogeneous firms across countries, price differences vary inversely with the elasticity of substitution. Anti-dumping duties should...... therefore also vary inversely with the elasticity of substitution at least for countries which have a strong focus on prices in the determination of their anti-dumping measures. We test this for ten countries from 1990 to 2009 using data on anti-dumping from Chad Bown (2010) and US-data at 8-digit level...... in our empirical investigation support the predicted role of the elasticity of substitution as we find a significant negative relation between the elasticity of substitution and the final anti-dumping duties for the ‘lesser duty rule’ group of countries. The countries which do not follow the ‘lesser duty...

  2. Substituted Hydroxyapatites with Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Joanna Kolmas

    2014-01-01

    Full Text Available Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency.

  3. Substituted Hydroxyapatites with Antibacterial Properties

    Science.gov (United States)

    Kolmas, Joanna; Groszyk, Ewa; Kwiatkowska-Różycka, Dagmara

    2014-01-01

    Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions) and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency. PMID:24949423

  4. Freeze-drying behaviour of pasteurized whole egg

    International Nuclear Information System (INIS)

    Melike Sakin; Merve Samli; Gizem Kor, A.; Figen Kaymak-Ertekin

    2009-01-01

    Because it provides full nutritional and certain desirable functional attributes, egg products are widely used as ingredients in many food products. Dried egg is especially valuable for being stable, easily mixable and having a long shelf life. It is necessary to know the effects of drying conditions onto the moisture removal behaviour and the functional properties of the powder product, to serve the egg powder as an alternative. An experimental study was conducted to achieve an understanding of the freeze-drying behaviour of pasteurized whole egg having 24% dry solids. In order to determine the moisture removal behaviour; the percent moisture loss (w/w), the average moisture content and the drying rates were obtained, the drying curves were developed and total drying times were determined, also the movement of the dry-wet boundary between the frozen layer and the dry porous layer formed by sublimation of ice crystals were investigated during a complete process. The physical properties of pasteurized whole egg such as; colour, water activity (a w ), the morphological structure (through SEM analysis) and functional properties (foam stability and dissolubility) were determined. The net colour change (ΔE) was about 22, independent of layer thickness. The water activity decreased to 0.22 at the end of drying. The SEM images of freeze-dried and slightly milled egg powder samples at magnification levels of 500 and 1000 showed the porous structure caused by sublimation of ice crystals generated within the egg structure during air blast freezing. The dissolubility and foaming capacity of powder egg were observed to be lower compared to those of pasteurized liquid egg. (author)

  5. Deep-freezing of boar semen in plastic film 'cochettes'.

    Science.gov (United States)

    Eriksson, B M; Rodriguez-Martinez, H

    2000-03-01

    The motility and membrane integrity of spermatozoa from nine boars frozen with a programmable freezing machine in plastic bags, 'cochettes', and in 'maxi-straws', in total doses of 5 x 10(9) spermatozoa/5 ml with glycerol (3%) used as cryoprotectant, were assessed after thawing. A computer-based cell motion analyser was used to evaluate sperm motility, while the integrity of the plasmalemma was assessed with fluorescent supravital dyes (C-FDA/PI). The fertilizing capacity of the semen frozen in the two containers was investigated by inseminating (AI) gilts. Pregnancy was monitored by Doppler-ultrasound, and the numbers of corpora lutea and viable embryos counted at slaughter, between days 30 and 38 after AI. The cochettes sustained the overall procedure of freezing/thawing (FT), with 30 min post-thaw (PT) sperm motility being significantly higher than for straws, 46.9 vs. 39.5%. The only significant difference in motility patterns detected when comparing the packages was a higher sperm velocity (VCL) in cochettes at 30 min PT. However, percentages of FT-spermatozoa with intact membranes, detected with the supravital probes, were higher in maxi-straws than in cochettes, 46.8 vs. 43.0% (P straws and those frozen in cochettes. The results indicate that although the deep-freezing of AI-doses of boar semen in large plastic bags is feasible, problems such as their inconvenient size for storage and inconsistent thawing must be solved before this type of container can be used for the commercial cryopreservation of boar semen.

  6. Frost heave susceptibility of saturated soil under constant rate of freezing

    Science.gov (United States)

    Ryokai, K.; Iguro, M.; Yoneyama, K.

    Introduced are the results of experiments carried out to quantitatively obtain the frost heave pressure and displacement of soil subjected to artificial freezing or freezing around in-ground liquefied natural gas storage tanks. This experiment is conducted to evaluate the frost heave susceptibility of saturated soil under overconsolidation. In other words, this experiment was carried out to obtain the relation of the over-burden pressure and freezing rate to the frost heave ratio by observing the frost heave displacement and freezing time of specimens by freezing the specimens at a constant freezing rate under a constant overburden pressure, while letting water freely flow in and out of the system. Introduced are the procedures for frost heave test required to quantitatively obtain the frost heave displacement and pressure of soil. Furthermore, the relation between the frost heave susceptibility and physical properties of soil obtained by this test is reported.

  7. Giant panda (Ailuropoda melanoleuca) sperm morphometry and function after repeated freezing and thawing.

    Science.gov (United States)

    Santiago-Moreno, J; Esteso, M C; Pradiee, J; Castaño, C; Toledano-Díaz, A; O'Brien, E; Lopez-Sebastián, A; Martínez-Nevado, E; Delclaux, M; Fernández-Morán, J; Zhihe, Z

    2016-05-01

    This work examines the effects of subsequent cycles of freezing-thawing on giant panda (Ailuropoda melanoleuca) sperm morphometry and function, and assesses whether density-gradient centrifugation (DGC) can increase the number of freezing-thawing cycles this sperm can withstand. A sperm sample was collected by electroejaculation from a mature giant panda and subjected to five freezing-thawing cycles. Although repeated freezing-thawing negatively affected (P 60% of the sperm cells in both treatments showed acrosome integrity even after the fifth freezing cycle. In fresh semen, the sperm head length was 4.7 μm, the head width 3.6 μm, area 14.3 μm(2) and perimeter length 14.1 μm. The present results suggest that giant panda sperm trends to be resistant to repeated freezing-thawing, even without DGC selection. © 2015 Blackwell Verlag GmbH.

  8. Effect of pasteurisation and freezing method on bioactive compounds and antioxidant activity of strawberry pulp.

    Science.gov (United States)

    Gonçalves, Gilma Auxiliadora Santos; Resende, Nathane Silva; Carvalho, Elisângela Elena Nunes; Resende, Jaime Vilela de; Vilas Boas, Eduardo Valério de Barros

    2017-09-01

    This study evaluated the stability of strawberry pulp subjected to three factors, pasteurisation (pasteurised and unpasteurised), freezing method (static air and forced air) and storage time (0, 2, 4 and 6 months). Pasteurisation favoured vitamin C retention during storage but enhanced the total loss of phenolics without affecting anthocyanin levels. Freezing by forced air was more effective in retaining phenolics during the first 4 months of storage, although the freezing method did not affect the anthocyanin levels. Processing and storage reduced the levels of individual phenolics. Freezing by forced air was more effective than static air in retaining antioxidant activity of the pulp. Polyphenol oxidase and peroxidase enzyme levels were relatively stable and independent of pasteurisation, freezing and storage time. Even after 6 months of frozen storage, strawberry pulp is a significant source of nutrients and bioactive compounds and retains high antioxidant capacity independent of pasteurisation and freezing method.

  9. Freezing process in unsaturated packed beds; Fuhowa ryushi sonai ni okeru suibun toketsu

    Energy Technology Data Exchange (ETDEWEB)

    Akahori, M; Aoki, K; Hattori, M [Nagaoka University of Technology, Niigata (Japan); Tani, T [Oji Paper Co. Ltd., Tokyo (Japan)

    1998-04-25

    The freezing process in unsaturated packed beds has been investigated experimentally and theoretically. Water transport to the frozen front plays an important part on freezing. The rate of the absorption of water into frozen layer depended on the freezing heat flux and the water saturation at the freezing front. As a result, ice content in the frozen layer was related to the rate of the absorption of water and the freezing heat flux. A one-dimensional freezing model in unsaturated packed beds has been presented, accounting for the water transport. The predicted water saturation and temperature distributions in the body and the thickness of frozen layer were compared with the experimental results using a porous bed composed of glass beads. 12 refs., 10 figs., 1 tab.

  10. Experimental research on durability of recycled aggregate concrete under freeze- thaw cycles

    Science.gov (United States)

    Cheng, Yanqiu; Shang, Xiaoyu; Zhang, Youjia

    2017-07-01

    The freeze-thaw durability of recycled aggregate concrete has significance for the concrete buildings in the cold region. In this paper, the rapid freezing and thawing cycles experience on recycle aggregate concrete was conducted to study on the effects of recycle aggregate amount, water-binder ratio and fly ash on freeze-thaw durability of recycle aggregate concrete. The results indicates that recycle aggregate amount makes the significant influence on the freeze-thaw durability. With the increase of recycled aggregates amount, the freeze-thaw resistance for recycled aggregate concrete decreases. Recycled aggregate concrete with lower water cement ratio demonstrates better performance of freeze-thaw durability. It is advised that the amount of fly ash is less than 30% for admixture of recycled aggregates in the cold region.

  11. Research on strength attenuation law of concrete in freezing - thawing environment

    Science.gov (United States)

    Xiao, qianhui; Cao, zhiyuan; Li, qiang

    2018-03-01

    By rapid freezing and thawing method, the experiments of concrete have been 300 freeze-thaw cycles specimens in the water. The cubic compression strength value under different freeze-thaw cycles was measured. By analyzing the test results, the water-binder ratio of the concrete under freeze-thaw environments, fly ash and air entraining agent is selected dosage recommendations. The exponential attenuation prediction model and life prediction model of compression strength of concrete under freezing-thawing cycles considering the factors of water-binder ratio, fly ash content and air-entraining agent dosage were established. The model provides the basis for predicting the durability life of concrete under freezing-thawing environment. It also provides experimental basis and references for further research on concrete structures with antifreeze requirements.

  12. Modeling competitive substitution in a polyelectrolyte complex

    International Nuclear Information System (INIS)

    Peng, B.; Muthukumar, M.

    2015-01-01

    We have simulated the invasion of a polyelectrolyte complex made of a polycation chain and a polyanion chain, by another longer polyanion chain, using the coarse-grained united atom model for the chains and the Langevin dynamics methodology. Our simulations reveal many intricate details of the substitution reaction in terms of conformational changes of the chains and competition between the invading chain and the chain being displaced for the common complementary chain. We show that the invading chain is required to be sufficiently longer than the chain being displaced for effecting the substitution. Yet, having the invading chain to be longer than a certain threshold value does not reduce the substitution time much further. While most of the simulations were carried out in salt-free conditions, we show that presence of salt facilitates the substitution reaction and reduces the substitution time. Analysis of our data shows that the dominant driving force for the substitution process involving polyelectrolytes lies in the release of counterions during the substitution

  13. THE BEHAVIOR OF DIFFERENT FIBERS AT BREAD DOUGH FREEZING

    Directory of Open Access Journals (Sweden)

    Jelena Filipović

    2008-11-01

    Full Text Available Three different types of commercial fibers (inulin originated from artichoke with long and short molecule chains and Fibrex - originated from sugar beet were incorporated into the dough formula as flour supplements at the level of 5 %. The influence of fiber characteristics on yeast dough (proving time and stability and bread quality (volume and crumb quality during 60 days freezing is presented. Data show that the addition of fibers in frozen yeast dough is positively contributing to preserving the quality of the final product and their influence depends on the characteristics of fibers.

  14. Deformed liquid marbles: Freezing drop oscillations with powders

    KAUST Repository

    Marston, Jeremy; Zhu, Y.; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

    2012-01-01

    In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

  15. Deformed liquid marbles: Freezing drop oscillations with powders

    KAUST Repository

    Marston, Jeremy

    2012-09-01

    In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

  16. Combined electrohydrodynamic (EHD) and vacuum freeze drying of shrimp

    International Nuclear Information System (INIS)

    Hu, Yucai; Huang, Qiang; Bai, Yaxiang

    2013-01-01

    To improve the drying qualities of shrimp, a combination of electrohydrodynamic (EHD) and vacuum freeze drying (FD) is examined. The drying rate, the shrinkage, the rehydration ratio, and the sensory properties including the color and trimness of the dried products under different drying methods (including combination drying of EHD and FD, EHD drying and FD drying) are measured. Compared with FD and EHD drying alone, the combined process consumes less drying time, and the product processed by combined drying displays lower shrinkage, higher rehydration rate and better sensory qualities.

  17. Determinants of generic drug substitution in Switzerland

    Directory of Open Access Journals (Sweden)

    Lufkin Thomas M

    2011-01-01

    Full Text Available Abstract Background Since generic drugs have the same therapeutic effect as the original formulation but at generally lower costs, their use should be more heavily promoted. However, a considerable number of barriers to their wider use have been observed in many countries. The present study examines the influence of patients, physicians and certain characteristics of the generics' market on generic substitution in Switzerland. Methods We used reimbursement claims' data submitted to a large health insurer by insured individuals living in one of Switzerland's three linguistic regions during 2003. All dispensed drugs studied here were substitutable. The outcome (use of a generic or not was modelled by logistic regression, adjusted for patients' characteristics (gender, age, treatment complexity, substitution groups and with several variables describing reimbursement incentives (deductible, co-payments and the generics' market (prices, packaging, co-branded original, number of available generics, etc.. Results The overall generics' substitution rate for 173,212 dispensed prescriptions was 31%, though this varied considerably across cantons. Poor health status (older patients, complex treatments was associated with lower generic use. Higher rates were associated with higher out-of-pocket costs, greater price differences between the original and the generic, and with the number of generics on the market, while reformulation and repackaging were associated with lower rates. The substitution rate was 13% lower among hospital physicians. The adoption of the prescribing practices of the canton with the highest substitution rate would increase substitution in other cantons to as much as 26%. Conclusions Patient health status explained a part of the reluctance to substitute an original formulation by a generic. Economic incentives were efficient, but with a moderate global effect. The huge interregional differences indicated that prescribing behaviours and

  18. Visual Indicators on Vaccine Boxes as Early Warning Tools to Identify Potential Freeze Damage.

    Science.gov (United States)

    Angoff, Ronald; Wood, Jillian; Chernock, Maria C; Tipping, Diane

    2015-07-01

    The aim of this study was to determine whether the use of visual freeze indicators on vaccines would assist health care providers in identifying vaccines that may have been exposed to potentially damaging temperatures. Twenty-seven sites in Connecticut involved in the Vaccine for Children Program participated. In addition to standard procedures, visual freeze indicators (FREEZEmarker ® L; Temptime Corporation, Morris Plains, NJ) were affixed to each box of vaccine that required refrigeration but must not be frozen. Temperatures were monitored twice daily. During the 24 weeks, all 27 sites experienced triggered visual freeze indicator events in 40 of the 45 refrigerators. A total of 66 triggered freeze indicator events occurred in all 4 types of refrigerators used. Only 1 of the freeze events was identified by a temperature-monitoring device. Temperatures recorded on vaccine data logs before freeze indicator events were within the 35°F to 46°F (2°C to 8°C) range in all but 1 instance. A total of 46,954 doses of freeze-sensitive vaccine were stored at the time of a visual freeze indicator event. Triggered visual freeze indicators were found on boxes containing 6566 doses (14.0% of total doses). Of all doses stored, 14,323 doses (30.5%) were of highly freeze-sensitive vaccine; 1789 of these doses (12.5%) had triggered indicators on the boxes. Visual freeze indicators are useful in the early identification of freeze events involving vaccines. Consideration should be given to including these devices as a component of the temperature-monitoring system for vaccines.

  19. Effects of Freezing and Thawing Cycle on Mechanical Properties and Stability of Soft Rock Slope

    OpenAIRE

    Chen, Yanlong; Wu, Peng; Yu, Qing; Xu, Guang

    2017-01-01

    To explore the variation laws of mechanical parameters of soft rock and the formed slope stability, an experiment was carried out with collected soft rock material specimens and freezing and thawing cycle was designed. Meanwhile, a computational simulation analysis of the freezing-thawing slope stability was implemented. Key factors that influence the strength of frozen rock specimens were analyzed. Results showed that moisture content and the number of freezing-thawing cycles influenced mech...

  20. Impact of nucleon mass shift on the freeze-out process

    International Nuclear Information System (INIS)

    Zschocke, Sven; Csernai, Laszlo Pal; Molnar, Etele; Nyiri, Agnes; Manninen, Jaakko

    2005-01-01

    The freeze-out of a massive nucleon gas through a finite layer with a timelike normal is studied. The impact of the in-medium nucleon mass shift on the freeze-out process is investigated. A considerable modification of the thermodynamic variables of temperature, flow velocity, energy density, and particle density has been found. Because of the nucleon mass shift the freeze-out particle distribution functions are changed noticeably in comparison with the evaluations, which use the vacuum nucleon mass

  1. Experimental analysis and modeling of ultrasound assisted freezing of potato spheres.

    Science.gov (United States)

    Kiani, Hossein; Zhang, Zhihang; Sun, Da-Wen

    2015-09-01

    In recent years, innovative methods such as ultrasound assisted freezing have been developed in order to improve the freezing process. During freezing of foods, accurate prediction of the temperature distribution, phase ratios, and process time is very important. In the present study, ultrasound assisted immersion freezing process (in 1:1 ethylene glycol-water solution at 253.15K) of potato spheres (0.02 m diameter) was evaluated using experimental, numerical and analytical approaches. Ultrasound (25 kHz, 890 W m(-2)) was irradiated for different duty cycles (DCs=0-100%). A finite volume based enthalpy method was used in the numerical model, based on which temperature and liquid fraction profiles were simulated by a program developed using OpenFOAM® CFD software. An analytical technique was also employed to calculate freezing times. The results showed that ultrasound irradiation could decrease the characteristic freezing time of potatoes. Since ultrasound irradiation increased the heat transfer coefficient but simultaneously generated heat at the surface of the samples, an optimum DC was needed for the shortest freezing time which occurred in the range of 30-70% DC. DCs higher than 70% increased the freezing time. DCs lower than 30% did not provide significant effects on the freezing time compared to the control sample. The numerical model predicted the characteristic freezing time in accordance with the experimental results. In addition, analytical calculation of characteristic freezing time exhibited qualitative agreement with the experimental results. As the numerical simulations provided profiles of temperature and water fraction within potatoes frozen with or without ultrasound, the models can be used to study and control different operation situations, and to improve the understanding of the freezing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Behavior of Plain Concrete of a High Water-Cement Ratio after Freeze-Thaw Cycles

    OpenAIRE

    Shang, Huai-Shuai; Yi, Ting-Hua; Song, Yu-Pu

    2012-01-01

    An experimental study of plain concrete specimens of water-cement ratio 0.55, subjected to 0, 15, 25, 40, 50 and 75 cycles of freeze-thaw was completed. The dynamic modulus of elasticity (DME), weight loss, compressive strength, tensile strength, flexural strength, cleavage strength and stress-strain relationships of plain concrete specimens suffering from freeze-thaw cycles were measured. The experimental results showed that the strength decreased as the freeze-thaw cycles were repeated. A c...

  3. Sensory Substitution and Multimodal Mental Imagery.

    Science.gov (United States)

    Nanay, Bence

    2017-09-01

    Many philosophers use findings about sensory substitution devices in the grand debate about how we should individuate the senses. The big question is this: Is "vision" assisted by (tactile) sensory substitution really vision? Or is it tactile perception? Or some sui generis novel form of perception? My claim is that sensory substitution assisted "vision" is neither vision nor tactile perception, because it is not perception at all. It is mental imagery: visual mental imagery triggered by tactile sensory stimulation. But it is a special form of mental imagery that is triggered by corresponding sensory stimulation in a different sense modality, which I call "multimodal mental imagery."

  4. Biologic and synthetic skin substitutes: An overview

    OpenAIRE

    Halim, Ahmad Sukari; Khoo, Teng Lye; Mohd. Yussof, Shah Jumaat

    2010-01-01

    The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substit...

  5. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin

    Science.gov (United States)

    2016-01-01

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4℃ for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4℃. Despite that SSF was conducted with the same method with SAF, application of artificial supercooling accelerated the phase transition (traverse from -0.6℃ to -5℃) from 3.07 h (SAF) to 2.23 h (SSF). The observation of a microstructure indicated that the SSF prevented tissue damage caused by ice crystallization and maintained the structural integrity. The estimated quality parameters reflected that SSF exhibited superior meat quality compared with slow freezing (SAF). SSF showed better water-holding capacity (lower thawing loss, cooking loss and expressible moisture) and tenderness than SAF, and these quality parameters of SSF were not significantly different with ultra-fast freezing treatment (EIF). Consequently, the results demonstrated that the generation of supercooling followed by conventional freezing potentially had the advantage of minimizing the quality deterioration caused by the slow freezing of meat. PMID:27857541

  6. Degradation of ATP and glycogen in cod ( Gadus morhua ) muscle during freezing

    DEFF Research Database (Denmark)

    Cappeln, Gertrud; Jessen, Flemming

    2001-01-01

    Changes in ATP, IMP, lactate and glycogen contents in the muscle of cod were followed during freezing at temperatures of -20C and -45C. ATP degradation was accompanied by a corresponding increase in IMP content. Simultaneous measurement of temperature showed that at both freezing rates......, the greatest decrease in ATP content was observed when the temperature reached -0.8C. Glycolysis occurred during freezing of cod as indicated by an increase in lactate content. The changes found in all measured metabolites were more pronounced when freezing was performed at a slow rate compared to a fast rate...

  7. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin.

    Science.gov (United States)

    Kim, Yiseul; Hong, Geun-Pyo

    2016-10-31

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4℃ for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4℃. Despite that SSF was conducted with the same method with SAF, application of artificial supercooling accelerated the phase transition (traverse from -0.6℃ to -5℃) from 3.07 h (SAF) to 2.23 h (SSF). The observation of a microstructure indicated that the SSF prevented tissue damage caused by ice crystallization and maintained the structural integrity. The estimated quality parameters reflected that SSF exhibited superior meat quality compared with slow freezing (SAF). SSF showed better water-holding capacity (lower thawing loss, cooking loss and expressible moisture) and tenderness than SAF, and these quality parameters of SSF were not significantly different with ultra-fast freezing treatment (EIF). Consequently, the results demonstrated that the generation of supercooling followed by conventional freezing potentially had the advantage of minimizing the quality deterioration caused by the slow freezing of meat.

  8. Folic acid content in thermostabilized and freeze-dried space shuttle foods

    Science.gov (United States)

    Lane, H. W.; Nillen, J. L.; Kloeris, V. L.

    1995-01-01

    This study was designed to determine whether freeze-dried and thermostabilized foods on a space shuttle contain adequate folate and to investigate any effects of freeze-drying on folacin. Frozen vegetables were analyzed after three states of processing: thawed; cooked; and rehydrated. Thermostabilized items were analyzed as supplied with no further processing. Measurable folate decreased in some freeze-dried vegetables and increased in others. Folacin content of thermostabilized food items was comparable with published values. We concluded that although the folacin content of some freeze-dried foods was low, adequate folate is available from the shuttle menu to meet RDA guidelines.

  9. Successful long-term preservation of rat sperm by freeze-drying.

    Directory of Open Access Journals (Sweden)

    Takehito Kaneko

    Full Text Available BACKGROUND: Freeze-drying sperm has been developed as a new preservation method where liquid nitrogen is no longer necessary. An advantage of freeze-drying sperm is that it can be stored at 4 °C and transported at room temperature. Although the successful freeze-drying of sperm has been reported in a number of animals, the possibility of long-term preservation using this method has not yet been studied. METHODOLOGY/PRINCIPAL FINDINGS: Offspring were obtained from oocytes fertilized with rat epididymal sperm freeze-dried using a solution containing 10 mM Tris and 1 mM EDTA adjusted to pH 8.0. Tolerance of testicular sperm to freeze-drying was increased by pre-treatment with diamide. Offspring with normal fertility were obtained from oocytes fertilized with freeze-dried epididymal sperm stored at 4 °C for 5 years. CONCLUSIONS AND SIGNIFICANCE: Sperm with -SS- cross-linking in the thiol-disulfide of their protamine were highly tolerant to freeze-drying, and the fertility of freeze-dried sperm was maintained for 5 years without deterioration. This is the first report to demonstrate the successful freeze-drying of sperm using a new and simple method for long-term preservation.

  10. Intact preservation of environmental samples by freezing under an alternating magnetic field.

    Science.gov (United States)

    Morono, Yuki; Terada, Takeshi; Yamamoto, Yuhji; Xiao, Nan; Hirose, Takehiro; Sugeno, Masaya; Ohwada, Norio; Inagaki, Fumio

    2015-04-01

    The study of environmental samples requires a preservation system that stabilizes the sample structure, including cells and biomolecules. To address this fundamental issue, we tested the cell alive system (CAS)-freezing technique for subseafloor sediment core samples. In the CAS-freezing technique, an alternating magnetic field is applied during the freezing process to produce vibration of water molecules and achieve a stable, super-cooled liquid phase. Upon further cooling, the temperature decreases further, achieving a uniform freezing of sample with minimal ice crystal formation. In this study, samples were preserved using the CAS and conventional freezing techniques at 4, -20, -80 and -196 (liquid nitrogen) °C. After 6 months of storage, microbial cell counts by conventional freezing significantly decreased (down to 10.7% of initial), whereas that by CAS-freezing resulted in minimal. When Escherichia coli cells were tested under the same freezing conditions and storage for 2.5 months, CAS-frozen E. coli cells showed higher viability than the other conditions. In addition, an alternating magnetic field does not impact on the direction of remanent magnetization in sediment core samples, although slight partial demagnetization in intensity due to freezing was observed. Consequently, our data indicate that the CAS technique is highly useful for the preservation of environmental samples. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  11. Estimation of Freezing Point of Hydrocarbon and Hydrofluorocarbon Mixtures for Mixed Refrigerant jt Cryocooler

    Science.gov (United States)

    Hwang, G.; Lee, J.; Jeong, S.

    2010-04-01

    Estimating the freezing point of refrigerant is an essential part in designing an MR JT (Mixed refrigerant Joule-Thomson) cryocooler to prevent itself from clogging and to operate with stability. There were researches on estimating freezing point, but some of them resulted in the wrong prediction of clogging. In this paper, the freezing point of the MR is precisely estimated with caution of clogging. The solubility of HC (hydrocarbon) and HFC (hydrofluorocarbon) mixture components are obtained with their activity coefficients, which represent the molecular interaction among the components. The freezing points of the MR JT cryocooler are systematically investigated in the operating temperature range from 70 K to 90 K.

  12. NMR Pore Structure and Dynamic Characteristics of Sandstone Caused by Ambient Freeze-Thaw Action

    Directory of Open Access Journals (Sweden)

    Bo Ke

    2017-01-01

    Full Text Available For a deeper understanding of the freeze-thaw weathering effects on the microstructure evolution and deterioration of dynamic mechanical properties of rock, the present paper conducted the nuclear magnetic resonance (NMR tests and impact loading experiments on sandstone under different freeze-thaw cycles. The results of NMR test show that, with the increase of freeze-thaw cycles, the pores expand and pores size tends to be uniform. The experimental results show that the stress-strain curves all go through four stages, namely, densification, elasticity, yielding, and failure. The densification curve is shorter, and the slope of elasticity curve decreases as the freeze-thaw cycles increase. With increasing freeze-thaw cycles, the dynamic peak stress decreases and energy absorption of sandstone increases. The dynamic failure form is an axial splitting failure, and the fragments increase and the size diminishes with increasing freeze-thaw cycles. The higher the porosity is, the more severe the degradation of dynamic characteristics is. An increase model for the relationships between the porosity or energy absorption and freeze-thaw cycles number was built to reveal the increasing trend with the freeze-thaw cycles increase; meanwhile, a decay model was built to predict the dynamic compressive strength degradation of rock after repeated freeze-thaw cycles.

  13. Alcohol Brine Freezing of Japanese Horse Mackerel (Trachurus japonicus) for Raw Consumption

    Science.gov (United States)

    Maeda, Toshimichi; Yuki, Atsuhiko; Sakurai, Hiroshi; Watanabe, Koichiro; Itoh, Nobuo; Inui, Etsuro; Seike, Kazunori; Mizukami, Yoichi; Fukuda, Yutaka; Harada, Kazuki

    In order to test the possible application of alcohol brine freezing to Japanese horse mackerel (Trachurus japonicus) for raw consumption, the quality and taste of fish frozen by direct immersion in 60% ethanol brine at -20, -25 and -30°C was compared with those by air freezing and fresh fish without freezing. Cracks were not found during the freezing. Smell of ethanol did not remain. K value, an indicator of freshness, of fish frozen in alcohol brine was less than 8.3%, which was at the same level as those by air freezing and fresh fish. Oxidation of lipid was at the same level as air freezing does, and lower than that of fresh fish. The pH of fish frozen in alcohol brine at -25 and -30°C was 6.5 and 6.6, respectively, which were higher than that by air freezing and that of fresh fish. Fish frozen in alcohol brine was better than that by air and at the same level as fresh fish in total evaluation of sensory tests. These results show that the alcohol brine freezing is superior to air freezing, and fish frozen in alcohol brine can be a material for raw consumption. The methods of thawing in tap water, cold water, refrigerator, and at room temperature were compared. Thawing in tap water is considered to be convenient due to the short thaw time and the quality of thawed fish that was best among the methods.

  14. Anti-freezing of air-cooled heat exchanger by switching off sectors

    International Nuclear Information System (INIS)

    Wang, Weijia; Kong, Yanqiang; Huang, Xianwei; Yang, Lijun; Du, Xiaoze; Yang, Yongping

    2017-01-01

    Highlights: • The anti-freezing of air-cooled heat exchanger by switching off sectors is studied. • The water side heat loads of various sectors are compared for different cases. • Anti-freezing turbine back pressure is proposed and obtained for various cases. • As wind speed increases, the energy efficiency can be clearly improved by sector off. • By switching frontal sector off, anti-freezing operation is most energy efficient. - Abstract: With the air side huge heat transfer surface, the air-cooled heat exchanger will take a serious freezing risk in cold winter. Therefore, it is of benefit to the safe operation of natural draft dry cooling system to propose the anti-freezing measures. In this work, the flow and heat transfer models of the cooling air coupling with the circulating water, are developed and numerically simulated for the anti-freezing by switching various sectors off. The local thermo-flow fields of cooling air are presented, and the water side heat loads of various sectors are compared for various cases. The anti-freezing turbine back pressure is proposed and obtained for the energy efficiency analysis. The results show that the sector switching off approach can effectively prevent the air-cooled heat exchanger from freezing and improve the energy efficiency of the cooling system, especially at high wind speeds. Moreover, with the frontal sector switching off, the most energy efficient anti-freezing operation of natural draft dry cooling system can be achieved.

  15. A Numerical and Experimental Investigation of the Internal Flow of a Freezing Water Droplet

    OpenAIRE

    Karlsson, Linn

    2015-01-01

    The overarching aim of this work is to study the freezing process of a single water droplet freezing on a cold surface, which is an interesting and important phenomenon with possible applications in many areas. Understanding the freezing process of a single water droplet is for example an important step when preventing unwanted icing, e.g. in the case of airplane wings and propellers, wind turbine rotor blades, and road surfaces.As a step in understanding the freezing process, the study speci...

  16. Precipitation of salts in freezing seawater and ozone depletion events: a status report

    Directory of Open Access Journals (Sweden)

    S. Morin

    2008-12-01

    Full Text Available In springtime, the polar marine boundary layer exhibits drastic ozone depletion events (ODEs, associated with elevated bromine oxide (BrO mixing ratios. The current interpretation of this peculiar chemistry requires the existence of acid and bromide-enriched surfaces to heterogeneously promote and sustain ODEs. Sander et al. (2006 have proposed that calcium carbonate (CaCO3 precipitation in any seawater-derived medium could potentially decrease its alkalinity, making it easier for atmospheric acids such as HNO3 and H2SO4 to acidify it. We performed simulations using the state-of-the-art FREZCHEM model, capable of handling the thermodynamics of concentrated electrolyte solutions, to try to reproduce their results, and found that when ikaite (CaCO3·6H2O rather than calcite (CaCO3 precipitates, there is no such effect on alkalinity. Given that ikaite has recently been identified in Antarctic brines (Dieckmann et al., 2008, our results show that great caution should be exercised when using the results of Sander et al. (2006, and reveal the urgent need of laboratory investigations on the actual link(s between bromine activation and the pH of the surfaces on which it is supposed to take place at subzero temperature. In addition, the evolution of the Cl/Br ratio in the brine during freezing was computed using FREZCHEM, taking into account Br substitutions in Cl–containing salts.

  17. A New Mechanism of Canopy Effect in Unsaturated Freezing Soils

    Directory of Open Access Journals (Sweden)

    Teng Jidong

    2016-01-01

    Full Text Available Canopy effect refers to the phenomenon where moisture accumulates underneath an impervious cover. Field observation reveals that canopy effect can take place in relatively dry soils where the groundwater table is deep and can lead to full saturation of the soil immediately underneath the impervious cover. On the other hand, numerical analysis based on existing theories of heat and mass transfer in unsaturated soils can only reproduce a minor amount of moisture accumulation due to an impervious cover, particularly when the groundwater table is relatively deep. In attempt to explain the observed canopy effect in field, this paper proposes a new mechanism of moisture accumulation in unsaturated freezing soils: vapour transfer in such a soil is accelerated by the process of vapour-ice desublimation. A new approach for modelling moisture and heat movements is proposed, in which the phase change of evaporation, condensation and de-sublimation of vapor flow are taken into account. The computed results show that the proposed model can indeed reproduce the unusual moisture accumulation observed in relatively dry soils. The results also demonstrate that soil freezing fed by vapour transfer can result in a water content close to full saturation. Since vapour transfer is seldom considered in geotechnical design, the canopy effect deserves more attention during construction and earth works in cold and arid regions.

  18. Unveiling CO2 heterogeneous freezing plumes during champagne cork popping.

    Science.gov (United States)

    Liger-Belair, Gérard; Cordier, Daniel; Honvault, Jacques; Cilindre, Clara

    2017-09-14

    Cork popping from clear transparent bottles of champagne stored at different temperatures (namely, 6, 12, and 20 °C) was filmed through high-speed video imaging in the visible light spectrum. During the cork popping process, a plume mainly composed of gaseous CO 2 with traces of water vapour freely expands out of the bottleneck through ambient air. Most interestingly, for the bottles stored at 20 °C, the characteristic grey-white cloud of fog classically observed above the bottlenecks of champagne stored at lower temperatures simply disappeared. It is replaced by a more evanescent plume, surprisingly blue, starting from the bottleneck. We suggest that heterogeneous freezing of CO 2 occurs on ice water clusters homogeneously nucleated in the bottlenecks, depending on the saturation ratio experienced by gas-phase CO 2 after adiabatic expansion (indeed highly bottle temperature dependent). Moreover, and as observed for the bottles stored at 20 °C, we show that the freezing of only a small portion of all the available CO 2 is able to pump the energy released through adiabatic expansion, thus completely inhibiting the condensation of water vapour found in air packages adjacent to the gas volume gushing out of the bottleneck.

  19. Freezing effect on bread appearance evaluated by digital imaging

    Science.gov (United States)

    Zayas, Inna Y.

    1999-01-01

    In marketing channels, bread is sometimes delivered in a frozen sate for distribution. Changes occur in physical dimensions, crumb grain and appearance of slices. Ten loaves, twelve bread slices per loaf were scanned for digital image analysis and then frozen in a commercial refrigerator. The bread slices were stored for four weeks scanned again, permitted to thaw and scanned a third time. Image features were extracted, to determine shape, size and image texture of the slices. Different thresholds of grey levels were set to detect changes that occurred in crumb, images were binarized at these settings. The number of pixels falling into these gray level settings were determined for each slice. Image texture features of subimages of each slice were calculated to quantify slice crumb grain. The image features of the slice size showed shrinking of bread slices, as a results of freezing and storage, although shape of slices did not change markedly. Visible crumb texture changes occurred and these changes were depicted by changes in image texture features. Image texture features showed that slice crumb changed differently at the center of a slice compared to a peripheral area close to the crust. Image texture and slice features were sufficient for discrimination of slices before and after freezing and after thawing.

  20. Substitution within the Danish printing industry

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred; Bøg, Carsten

    2009-01-01

    are running a substitution project. A major part of the work has been mapping the presence of chemicals which are potential candidates for substitution (e.g. PBT, CMR, vPvB, EDS) within the Danish printing industry and this work was recently finished. The mapping comprises a combination of a literature study......The implementation of the EU REACH regulation will most probably promote substitution within sectors handling a lot of different chemicals like the printing industry. With the aim of being at the cutting edge of this development the Danish EPA together with the Danish printing industry and IPU...... total 15 substances) were found in the Danish printing industry. This paper presents the results of the mapping of chemical candidates and the first results on preparing for actual substitutions....

  1. Substituted hydroxyapatites for biomedical applications: A review

    Czech Academy of Sciences Publication Activity Database

    Šupová, Monika

    2015-01-01

    Roč. 41, č. 8 (2015), s. 9203-9231 ISSN 0272-8842 Institutional support: RVO:67985891 Keywords : bioapatite * calcium phosphate * hydroxyapatite * substitution Subject RIV: JJ - Other Materials Impact factor: 2.758, year: 2015

  2. Dodecatungstocobaltate and Sn (IV)-Substituted Polyoxometalate ...

    African Journals Online (AJOL)

    NICO

    work metals, or substituting different cations for the protons to make their acidic or neutral ... corrosive materials in comparison with traditional Lewis acids. The importance of .... salt by treatment with potassium chloride. Finally, the cobalt (II).

  3. Questioning nuclear waste substitution: a case study.

    Science.gov (United States)

    Marshall, Alan

    2007-03-01

    This article looks at the ethical quandaries, and their social and political context, which emerge as a result of international nuclear waste substitution. In particular it addresses the dilemmas inherent within the proposed return of nuclear waste owned by Japanese nuclear companies and currently stored in the United Kingdom. The UK company responsible for this waste, British Nuclear Fuels Limited (BNFL), wish to substitute this high volume intermediate-level Japanese-owned radioactive waste for a much lower volume of much more highly radioactive waste. Special focus is given to ethical problems that they, and the UK government, have not wished to address as they move forward with waste substitution. The conclusion is that waste substitution can only be considered an ethical practice if a set of moderating conditions are observed by all parties. These conditions are listed and, as of yet, they are not being observed.

  4. DOES CURRENCY SUBSTITUTION AFFECT EXCHANGE RATE VOLATILITY?

    Directory of Open Access Journals (Sweden)

    Hisao Kumamoto

    2014-10-01

    Full Text Available This study investigates the impacts of the degree of currency substitution on nominal exchange rate volatility in seven countries (Indonesia, the Philippines, the Czech Republic, Hungary, Poland, Argentina, and Peru. We use the Threshold ARCH model to consider the ratchet effect of currency substitution and sample periods in the 2000s, during which time the economies of the sample countries stabilized, while the U.S. dollar and euro depreciated against other major currencies following the recent global financial crisis. The presented empirical analyses show that the degree of currency substitution has significant positive effects on the conditional variance of the depreciation rate of the nominal exchange rate in most sample countries. Moreover, a shock to the depreciation rate of the nominal exchange rate has asymmetric effects on the conditional variance, depending on the sign. One possible explanation for these differential effects is the existence of the ratchet effect of currency substitution.

  5. Development of a diesel substitute fuel

    Energy Technology Data Exchange (ETDEWEB)

    Reiter, Anton; Mair-Zelenka, Philipp [Graz Univ. of Technology (Austria). Inst. of Chemical Engineering and Environmental Technology; Zeymer, Marc [OMV Refining and Marketing GmbH, Vienna (Austria). MRDI-D Product Development and Innovation

    2013-06-01

    Substitute fuels composed of few real chemical compounds are an alternative characterisation approach for conventional fuels as opposed to the traditional pseudo-component method. With the algorithm proposed in this paper the generation of such substitutes will be facilitated and well-established thermodynamic methods can be applied for physical property-data prediction. Based on some quality criteria like true boiling-point curve, liquid density, C/H ratio, or cloud point of a target fuel a surrogate which meets these properties is determined by fitting its composition. The application and capabilities of the algorithm developed are demonstrated by means of an exemplary diesel substitute fuel. The substitute mixture obtained can be generated and used for evaluation of property-prediction methods. Furthermore this approach can help to understand the effects of mixing fossil fuels with biogenic compounds. (orig.)

  6. Hyperfine magnetic fields in substituted Finemet alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brzózka, K., E-mail: k.brzozka@uthrad.pl [University of Technology and Humanities in Radom, Department of Physics (Poland); Sovák, P. [P.J. Šafárik University, Institute of Physics (Slovakia); Szumiata, T.; Gawroński, M.; Górka, B. [University of Technology and Humanities in Radom, Department of Physics (Poland)

    2016-12-15

    Transmission Mössbauer spectroscopy was used to determine the hyperfine fields of Finemet-type alloys in form of ribbons, substituted alternatively by Mn, Ni, Co, Al, Zn, V or Ge of various concentration. The comparative analysis of magnetic hyperfine fields was carried out which enabled to understand the role of added elements in as-quenched as well as annealed samples. Moreover, the influence of the substitution on the mean direction of the local hyperfine magnetic field was examined.

  7. Trace maps of general substitutional sequences

    International Nuclear Information System (INIS)

    Kolar, M.; Nori, F.

    1990-01-01

    It is shown that for arbitrary n, there exists a trace map for any n-letter substitutional sequence. Trace maps are explicitly obtained for the well-known circle and Rudin-Shapiro sequences which can be defined by means of substitution rules on three and four letters, respectively. The properties of the two trace maps and their consequences for various spectral properties are briefly discussed

  8. Product portfolio optimization based on substitution

    DEFF Research Database (Denmark)

    Myrodia, Anna; Moseley, A.; Hvam, Lars

    2017-01-01

    The development of production capabilities has led to proliferation of the product variety offered to the customer. Yet this fact does not directly imply increase of manufacturers' profitability, nor customers' satisfaction. Consequently, recent research focuses on portfolio optimization through...... substitution and standardization techniques. However when re-defining the strategic market decisions are characterized by uncertainty due to several parameters. In this study, by using a GAMS optimization model we present a method for supporting strategic decisions on substitution, by quantifying the impact...

  9. Currency Substitution and Inflation in Peru

    OpenAIRE

    Liliana Rojas-Suárez

    1992-01-01

    This paper shows that there is a long-run relationship between the expected rate of depreciation in the black-market-exchange rate and the ratio of domestic to foreign money in Peru; that is, the hypothesis of currency substitution can explain the behavior of real holdings of money in Peru. The paper also shows that, while the importance of currency substitution as a transmission mechanism through which domestic policies affected the dynamics of inflation was relatively small during a period ...

  10. Substituting missing data in compositional analysis

    Energy Technology Data Exchange (ETDEWEB)

    Real, Carlos, E-mail: carlos.real@usc.es [Area de Ecologia, Departamento de Biologia Celular y Ecologia, Escuela Politecnica Superior, Universidad de Santiago de Compostela, 27002 Lugo (Spain); Angel Fernandez, J.; Aboal, Jesus R.; Carballeira, Alejo [Area de Ecologia, Departamento de Biologia Celular y Ecologia, Facultad de Biologia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2011-10-15

    Multivariate analysis of environmental data sets requires the absence of missing values or their substitution by small values. However, if the data is transformed logarithmically prior to the analysis, this solution cannot be applied because the logarithm of a small value might become an outlier. Several methods for substituting the missing values can be found in the literature although none of them guarantees that no distortion of the structure of the data set is produced. We propose a method for the assessment of these distortions which can be used for deciding whether to retain or not the samples or variables containing missing values and for the investigation of the performance of different substitution techniques. The method analyzes the structure of the distances among samples using Mantel tests. We present an application of the method to PCDD/F data measured in samples of terrestrial moss as part of a biomonitoring study. - Highlights: > Missing values in multivariate data sets must be substituted prior to analysis. > The substituted values can modify the structure of the data set. > We developed a method to estimate the magnitude of the alterations. > The method is simple and based on the Mantel test. > The method allowed the identification of problematic variables in a sample data set. - A method is presented for the assessment of the possible distortions in multivariate analysis caused by the substitution of missing values.

  11. Substituting missing data in compositional analysis

    International Nuclear Information System (INIS)

    Real, Carlos; Angel Fernandez, J.; Aboal, Jesus R.; Carballeira, Alejo

    2011-01-01

    Multivariate analysis of environmental data sets requires the absence of missing values or their substitution by small values. However, if the data is transformed logarithmically prior to the analysis, this solution cannot be applied because the logarithm of a small value might become an outlier. Several methods for substituting the missing values can be found in the literature although none of them guarantees that no distortion of the structure of the data set is produced. We propose a method for the assessment of these distortions which can be used for deciding whether to retain or not the samples or variables containing missing values and for the investigation of the performance of different substitution techniques. The method analyzes the structure of the distances among samples using Mantel tests. We present an application of the method to PCDD/F data measured in samples of terrestrial moss as part of a biomonitoring study. - Highlights: → Missing values in multivariate data sets must be substituted prior to analysis. → The substituted values can modify the structure of the data set. → We developed a method to estimate the magnitude of the alterations. → The method is simple and based on the Mantel test. → The method allowed the identification of problematic variables in a sample data set. - A method is presented for the assessment of the possible distortions in multivariate analysis caused by the substitution of missing values.

  12. "On" freezing in Parkinson's disease: resistance to visual cue walking devices.

    Science.gov (United States)

    Kompoliti, K; Goetz, C G; Leurgans, S; Morrissey, M; Siegel, I M

    2000-03-01

    To measure "on" freezing during unassisted walking (UW) and test if two devices, a modified inverted stick (MIS) and a visual laser beam stick (LBS) improved walking speed and number of "on" freezing episodes in patients with Parkinson's disease (PD). Multiple visual cues can overcome "off' freezing episodes and can be useful in improving gait function in parkinsonian patients. These devices have not been specifically tested in "on" freezing, which is unresponsive to pharmacologic manipulations. Patients with PD, motor fluctuations and freezing while "on," attempted walking on a 60-ft track with each of three walking conditions in a randomized order: UW, MIS, and LBS. Total time to complete a trial, number of freezes, and the ratio of walking time to the number of freezes were compared using Friedman's test. Twenty-eight patients with PD, mean age 67.81 years (standard deviation [SD] 7.54), mean disease duration 13.04 years (SD 7.49), and mean motor Unified Parkinson's Disease Rating Scale score "on" 32.59 (SD 10.93), participated in the study. There was a statistically significant correlation of time needed to complete a trial and number of freezes for all three conditions (Spearman correlations: UW 0.973, LBS 0.0.930, and MIS 0.842). The median number of freezes, median time to walk in each condition, and median walking time per freeze were not significantly different in pairwise comparisons of the three conditions (Friedman's test). Of the 28 subjects, six showed improvement with the MIS and six with the LBS in at least one outcome measure. Assisting devices, specifically based on visual cues, are not consistently beneficial in overcoming "on" freezing in most patients with PD. Because this is an otherwise untreatable clinical problem and because occasional subjects do respond, cautious trials of such devices under the supervision of a health professional should be conducted to identify those patients who might benefit from their long-term use.

  13. Arginine and proline applied as food additives stimulate high freeze tolerance in larvae of Drosophila melanogaster.

    Science.gov (United States)

    Koštál, Vladimír; Korbelová, Jaroslava; Poupardin, Rodolphe; Moos, Martin; Šimek, Petr

    2016-08-01

    The fruit fly Drosophila melanogaster is an insect of tropical origin. Its larval stage is evolutionarily adapted for rapid growth and development under warm conditions and shows high sensitivity to cold. In this study, we further developed an optimal acclimation and freezing protocol that significantly improves larval freeze tolerance (an ability to survive at -5°C when most of the freezable fraction of water is converted to ice). Using the optimal protocol, freeze survival to adult stage increased from 0.7% to 12.6% in the larvae fed standard diet (agar, sugar, yeast, cornmeal). Next, we fed the larvae diets augmented with 31 different amino compounds, administered in different concentrations, and observed their effects on larval metabolomic composition, viability, rate of development and freeze tolerance. While some diet additives were toxic, others showed positive effects on freeze tolerance. Statistical correlation revealed tight association between high freeze tolerance and high levels of amino compounds involved in arginine and proline metabolism. Proline- and arginine-augmented diets showed the highest potential, improving freeze survival to 42.1% and 50.6%, respectively. Two plausible mechanisms by which high concentrations of proline and arginine might stimulate high freeze tolerance are discussed: (i) proline, probably in combination with trehalose, could reduce partial unfolding of proteins and prevent membrane fusions in the larvae exposed to thermal stress (prior to freezing) or during freeze dehydration; (ii) both arginine and proline are exceptional among amino compounds in their ability to form supramolecular aggregates which probably bind partially unfolded proteins and inhibit their aggregation under increasing freeze dehydration. © 2016. Published by The Company of Biologists Ltd.

  14. Bulk specimen X-ray microanalysis of freeze-fractured, freeze-dried tissues in gerontological research

    International Nuclear Information System (INIS)

    Nagy, I.

    1988-01-01

    The rationale for choosing the freeze-fracture freeze-drying (FFFD) method of biological bulk specimen preparation as well as the theoretical and practical problems of this method are treated. FFFD specimens are suitable for quantitative X-ray microanalysis of biologically relevant elements. Although the spatial resolution of this analytical technique is low, the application of properly selected bulk standard crystals as well as the measurement of the intracellular water and dry mass content by means of another method developed in the same laboratory, allow us to obtain useful information about the age-dependent changes of ionic composition in the main intracellular compartments. The paper summarizes the problems with regard to specimen preparation, beam penetration and the quantitative analysis of FFFD specimens. The method has been applied so far mainly for the analysis of intranuclear and intracytoplasmic concentrations of Na, C1 and K in various types of cells and has resulted in a significant contribution to our understanding of the cellular mechanisms of aging. 84 references

  15. [Guidelines for substitution treatments in prison populations].

    Science.gov (United States)

    Michel, L; Maguet, O

    2005-01-01

    Care access for the drug addict patients in prison (in particular for the treatments of substitution) in France is very unequal from one establishment to another. This reflects the great variability of the practices of substitution and especially the absence of consensus on the methods of adaptation of these practices to the prison environment. Because of difficulties expressed by prisoners and medical staff on this subject and of stakes (let us recall that approximately 30% of the prisoners are dependent or abusers of one or more psychoactive substances), the formulation of recommendations or of a good practices guide of substitution in prison appeared necessary. Work that we detail here answers a ordering of the Advisory Commission of the Treatments of Substitution (September 2001) whose authors are members. It was presented at the session April 2003. It results from the confrontation of a review of the literature (including legal texts and official reports concerning substitution, the organization of the care in prison environment and the lawful framework), with a vast investigation. The latter was carried out near medical staff (22 prisons), penitentiary staff (3 prisons, 27 people met including directors of these establishments) and prisoners (7 establishments, 28 prisoners met) in the form of individual talks (semi-directing interviews with evaluation of the type of existing device and its knowledge by the penitentiary staff and the prisoners; statement of the suggestions, needs and requests of the medical, penitentiary staffs and of the prisoners). In the whole visited prisons, 7.8% (870) of the prisoners received substitution treatments (6.35% by buprenorphine, 1.44% by methadone), representing a proportion of substituted drug addicts (870 substituted for an evaluation of 3,350 prisoners drug addicts among the 11,168 prisoners of the 22 visited prisons) notably lower than that in free environment (56%, ie 96,000 substituted for an evaluated population of

  16. Control of crystal growth in water purification by directional freeze crystallization

    Science.gov (United States)

    Conlon, William M. (Inventor)

    1996-01-01

    A Directional Freeze Crystallization system employs an indirect contact heat exchanger to freeze a fraction of liquid to be purified. The unfrozen fraction is drained away and the purified frozen fraction is melted. The heat exchanger must be designed in accordance with a Growth Habit Index to achieve efficient separation of contaminants. If gases are dissolved in the liquid, the system must be pressurized.

  17. Model-based optimization of the primary drying step during freeze-drying

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F.C.; Van Bockstal, Pieter-Jan; Nopens, Ingmar

    2015-01-01

    Since large molecules are considered the key driver for growth of the pharmaceutical industry, the focus of the pharmaceutical industry is shifting from small molecules to biopharmaceuticals: around 50% of the approved biopharmaceuticals are freeze-dried products. Therefore, freeze- drying is an ...

  18. Stability of arsenic compounds in seafood samples during processing and storage by freezing

    DEFF Research Database (Denmark)

    Dahl, Lisbeth; Molin, Marianne; Amlund, Heidi

    2010-01-01

    was observed after processing or after storage by freezing. The content of tetramethylarsonium ion was generally low in all samples types, but increased significantly in all fried samples of both fresh and frozen seafood. Upon storage by freezing, the arsenobetaine content was reduced significantly, but only...

  19. 9 CFR 354.244 - Temperatures and cooling and freezing procedures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Temperatures and cooling and freezing procedures. 354.244 Section 354.244 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... and cooling and freezing procedures. Temperatures and procedures which are necessary for cooling and...

  20. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Temperatures and chilling and freezing procedures. 381.66 Section 381.66 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and...

  1. 21 CFR 864.9225 - Cell-freezing apparatus and reagents for in vitro diagnostic use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cell-freezing apparatus and reagents for in vitro diagnostic use. 864.9225 Section 864.9225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... Establishments That Manufacture Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...

  2. Consumer behaviour and knowledge related to freezing and defrosting meat at home: An exploratory study

    NARCIS (Netherlands)

    Damen, F.W.M.; Steenbekkers, L.P.A.

    2007-01-01

    The purpose of this paper is to gain insight into the ways consumers freeze and defrost meat, the reasons for their behaviour and the knowledge they have about the process of freezing and defrosting. Consumers are aware of the microbiological safety risks involved in the consumption of meat.

  3. DNA comet assay to identify different freezing temperatures of irradiated liver chicken

    International Nuclear Information System (INIS)

    Duarte, Renato C.; Mozeika, Michel A.; Fanaro, Gustavo B.; Villavicencio, Anna L.C.H.; Marchioni, Eric

    2009-01-01

    The cold chain is a succession of steps which maintain the food at low temperature. The thawed food never be frozen again and the best solution being to consume it quickly to avoid the microorganism growth which causes decay and nutrients damage. One of most important point is that freezing process, unlike irradiation, do not destroy microorganisms, only inactive them as long as they remain in a frozen state. The Comet Assay is an original test used to detect irradiated foods that's recognize the DNA damage and can then be used to control the overall degradation of the food and in a certain extend to evaluate the damage caused by irradiation, different forms of freeze and storage time on liver chicken cells. Different freezing temperatures were used, deep freeze -196 deg C and slow freeze -10 deg C. Samples were irradiated in a 60 Co irradiator with 1.5, 3.0 and 4.5 kGy radiation doses. Fast freezing technique induces a low percent of DNA degradation comparing to slow freezing technique. This procedure could be a good choose to chicken freezing processing. (author)

  4. Nitrate and dissolved organic carbon mobilization in response to soil freezing variability

    Science.gov (United States)

    Colin B. Fuss; Charles T. Driscoll; Peter M. Groffman; John L. Campbell; Lynn M. Christenson; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer; Jorge Durán; Jennifer L. Morse

    2016-01-01

    Reduced snowpack and associated increases in soil freezing severity resulting from winter climate change have the potential to disrupt carbon (C) and nitrogen (N) cycling in soils. We used a natural winter climate gradient based on elevation and aspect in a northern hardwood forest to examine the effects of variability in soil freezing depth, duration, and frequency on...

  5. Cognitive Contributions to Freezing of Gait in Parkinson Disease: Implications for Physical Rehabilitation.

    Science.gov (United States)

    Peterson, Daniel S; King, Laurie A; Cohen, Rajal G; Horak, Fay B

    2016-05-01

    People with Parkinson disease (PD) who show freezing of gait also have dysfunction in cognitive domains that interact with mobility. Specifically, freezing of gait is associated with executive dysfunction involving response inhibition, divided attention or switching attention, and visuospatial function. The neural control impairments leading to freezing of gait have recently been attributed to higher-level, executive and attentional cortical processes involved in coordinating posture and gait rather than to lower-level, sensorimotor impairments. To date, rehabilitation for freezing of gait primarily has focused on compensatory mobility training to overcome freezing events, such as sensory cueing and voluntary step planning. Recently, a few interventions have focused on restitutive, rather than compensatory, therapy. Given the documented impairments in executive function specific to patients with PD who freeze and increasing evidence of overlap between cognitive and motor function, incorporating cognitive challenges with mobility training may have important benefits for patients with freezing of gait. Thus, a novel theoretical framework is proposed for exercise interventions that jointly address both the specific cognitive and mobility challenges of people with PD who freeze. © 2016 American Physical Therapy Association.

  6. Application of freeze-drying technology in manufacturing orally disintegrating films.

    Science.gov (United States)

    Liew, Kai Bin; Odeniyi, Michael Ayodele; Peh, Kok-Khiang

    2016-01-01

    Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.

  7. Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

    NARCIS (Netherlands)

    Snijders, A.H.; Leunissen, H.P.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    Freezing of gait is a common, debilitating feature of Parkinson’s disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

  8. Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

    NARCIS (Netherlands)

    Snijders, A.H.; Leunissen, I.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

  9. DNA comet assay to identify different freezing temperatures of irradiated liver chicken

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Renato C.; Mozeika, Michel A.; Fanaro, Gustavo B.; Villavicencio, Anna L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: renatocduarte@yahoo.com.br; Marchioni, Eric [Universite de Strasbourg, Illkirch (France). Faculte de Pharmacie. Lab. de Chimie Analytique et Sciences de l' Aliment

    2009-07-01

    The cold chain is a succession of steps which maintain the food at low temperature. The thawed food never be frozen again and the best solution being to consume it quickly to avoid the microorganism growth which causes decay and nutrients damage. One of most important point is that freezing process, unlike irradiation, do not destroy microorganisms, only inactive them as long as they remain in a frozen state. The Comet Assay is an original test used to detect irradiated foods that's recognize the DNA damage and can then be used to control the overall degradation of the food and in a certain extend to evaluate the damage caused by irradiation, different forms of freeze and storage time on liver chicken cells. Different freezing temperatures were used, deep freeze -196 deg C and slow freeze -10 deg C. Samples were irradiated in a {sup 60}Co irradiator with 1.5, 3.0 and 4.5 kGy radiation doses. Fast freezing technique induces a low percent of DNA degradation comparing to slow freezing technique. This procedure could be a good choose to chicken freezing processing. (author)

  10. Reagan and the Nuclear Freeze: "Stars Wars" as a Rhetorical Strategy.

    Science.gov (United States)

    Bjork, Rebecca S.

    1988-01-01

    Analyzes the interaction between nuclear freeze activists and proponents of a Strategic Defense Initiative (SDI). Argues that SDI strengthens Reagan's rhetorical position concerning nuclear weapons policy because it reduces the argumentative ground of the freeze movement by envisioning a defensive weapons system that would nullify nuclear weapons.…

  11. Globally important nitrous oxide emissions from croplands induced by freeze-thaw cycles

    NARCIS (Netherlands)

    Wagner-Riddle, Claudia; Congreves, Katelyn A.; Abalos Rodriguez, Diego; Berg, Aaron A.; Brown, Shannon E.; Ambadan, Jaison Thomas; Gao, Xiaopeng; Tenuta, Mario

    2017-01-01

    Seasonal freezing induces large thaw emissions of nitrous oxide, a trace gas that contributes to stratospheric ozone destruction and atmospheric warming. Cropland soils are by far the largest anthropogenic source of nitrous oxide. However, the global contribution of seasonal freezing to nitrous

  12. L-Band Microwave Emission of Soil Freeze-Thaw Process in the Third Pole Environment

    NARCIS (Netherlands)

    Zheng, Donghai; van der Velde, R.; Su, Z.; Zeng, Y.

    2017-01-01

    Soil freeze-thaw transition monitoring is essential for quantifying climate change and hydrologic dynamics over cold regions, for instance, the Third Pole. We investigate the L-band (1.4 GHz) microwave emission characteristics of soil freeze-thaw cycle via analysis of tower-based brightness

  13. Charge-charge liquid structure factor and the freezing of alkali halides

    International Nuclear Information System (INIS)

    March, N.H.; Tosi, M.P.

    1980-10-01

    The peak height of the charge-charge liquid structure factor Ssub(QQ) in molten alkali halides is proposed as a criterion for freezing. Available data on molten alkali chlorides, when extrapolated to the freezing point suggests Ssub(QQ)sup(max) approximately 5. (author)

  14. Degradation of ATP and glycogen in cod ( Gadus morhua ) muscle during freezing

    DEFF Research Database (Denmark)

    Cappeln, Gertrud; Jessen, Flemming

    2001-01-01

    , the greatest decrease in ATP content was observed when the temperature reached -0.8C. Glycolysis occurred during freezing of cod as indicated by an increase in lactate content. The changes found in all measured metabolites were more pronounced when freezing was performed at a slow rate compared to a fast rate...

  15. Key composition optimization of meat processed protein source by vacuum freeze-drying technology

    Directory of Open Access Journals (Sweden)

    Yan Ma

    2018-05-01

    Full Text Available Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined. Keywords: Ham, Tenderloin, Vacuum freeze-dry, Processing, Optimization

  16. Projecting potential adoption of genetically engineered freeze-tolerant Eucalyptus in the United States

    Science.gov (United States)

    David N. Wear; Ernest Dixon IV; Robert C. Abt; Navinder Singh

    2015-01-01

    Development of commercial Eucalyptus plantations has been limited in the United States because of the species’ sensitivity to freezing temperatures. Recently developed genetically engineered clones of a Eucalyptus hybrid, which confer freeze tolerance, could expand the range of commercial plantations. This study explores how...

  17. The human milk oligosaccharides are not affected by pasteurization and freeze-drying.

    Science.gov (United States)

    Hahn, Won-Ho; Kim, Jaehan; Song, Seunghyun; Park, Suyeon; Kang, Nam Mi

    2017-11-06

    Human milk oligosaccharides (HMOs) are known as important factors in neurologic and immunologic development of neonates. Moreover, freeze-drying seems to be a promising storage method to improve the processes of human milk banks. However, the effects of pasteurization and freeze-drying on HMOs were not evaluated yet. The purpose of this study is to analyze and compare the HMOs profiles of human milk collected before and after the pasteurization and freeze-drying. Totally nine fresh human milk samples were collected from three healthy mothers at the first, second, and third week after delivery. The samples were treated with Holder pasteurization and freeze-drying. HMOs profiles were analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time-of-flight (TOF/TOF) mass spectrometry and compared between samples collected before and after the treatments. Human milk samples showed significantly different HMO patterns between mothers. However, HMOs were not affected by lactation periods within 3 weeks after delivery (r 2  = 0.972-0.999, p pasteurization and freeze-drying were found not to affect HMO patterns in a correlation analysis (r 2  = 0.989-0.999, p pasteurization and freeze-drying of donor milks. We hope that introducing freeze-drying to the human milk banks would be encouraged by the present study. However, the storage length without composition changes of HMOs after freeze-drying needs to be evaluated in the further studies.

  18. Cortical correlates of susceptibility to upper limb freezing in Parkinson's disease

    NARCIS (Netherlands)

    Scholten, M.; Govindan, R.B.; Braun, C.; Bloem, B.R.; Plewnia, C.; Kruger, R.; Gharabaghi, A.; Weiss, D.

    2016-01-01

    OBJECTIVE: Freezing behavior is an unmet symptom in Parkinson's disease (PD), which reflects its complex pathophysiology. Freezing behavior can emerge when attentional capacity is reduced, i.e. under dual task interference. In this study, we characterized the cortical network signatures underlying

  19. Direct comparative analysis of conventional and directional freezing for the cryopreservation of whole ovaries

    NARCIS (Netherlands)

    Maffei, S.; Hanenberg, M.; Pennarossa, G.; Roberto V. Silva, J.; Tiziana, A.; Brevini, L.; Pharm, D.; Arav, A.; Gandolfi, F.

    2013-01-01

    INTERVENTION(S): Eighty-one ovaries were randomly assigned to fresh control, conventional freezing (CF), and directional freezing (DF) group. Ovaries of CF and DF groups were perfused via the ovarian artery with Leibovitz L-15 medium, 10% fetal bovine serum, and 1.5 M dimethyl sulfoxide for 5

  20. Three-Dimensional Microstructure of Biological Tissues during Freezing and Thawing

    Science.gov (United States)

    Ishiguro, Hiroshi; Horimizu, Takashi; Kataori, Akinobu; Kajigaya, Hiroshi

    Three-dimensional behavior of ice crystals and cells during the freezing and thawing of biological tissues was investigated microscopically in real time by using a confocal laser scanning microscope(CLSM) and a fluorescent dye, acridine orange (AO). Fresh tender meat (2nd pectoral muscles) of chicken was stained with the AO in physiological saline to distinguish ice crystals and cells by their different colors, and then frozen and thawed under two different thermal protocols: a) slow-cooling and rapid-warming and b) rapid-cooling and rapid-warming. The CLSM noninvasively produced optical tomograms of the tissues to clarify the pattern of freezing, morphology of ice crystals in the tissues, and the interaction between ice crystals and cells. Also, the tissues were morphologically investigated by pathological means after the freezing and thawing. Typical freezing pattern during the slow-cooling was extracellular-freezing, and those during the rapid-cooling were extracellular-freezing and intracellular freezing with a lot of fine ice crystals in the cells. Cracks caused by the extracellular and intracellular ice crystals remained in the muscle tissues after the thawing. The results obtained by using the CLSM/dye method were consistent with pathologically morphological changes in the tissues through freezing and thawing.

  1. PHBV/PLLA-based composite scaffolds fabricated using an emulsion freezing/freeze-drying technique for bone tissue engineering: surface modification and in vitro biological evaluation

    International Nuclear Information System (INIS)

    Sultana, Naznin; Wang Min

    2012-01-01

    Tissue engineering combines living cells with biodegradable materials and/or bioactive components. Composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramic with suitable properties are promising for bone tissue regeneration. In this paper, based on blending two biodegradable and biocompatible polymers, namely poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(l-lactic acid) (PLLA) with incorporated nano hydroxyapatite (HA), three-dimensional composite scaffolds with controlled microstructures and an interconnected porous structure, together with high porosity, were fabricated using an emulsion freezing/freeze-drying technique. The influence of various parameters involved in the emulsion freezing/freeze-drying technique was studied for the fabrication of good-quality polymer scaffolds based on PHBV polymers. The morphology, mechanical properties and crystallinity of PHBV/PLLA and HA in PHBV/PLLA composite scaffolds and PHBV polymer scaffolds were studied. The scaffolds were coated with collagen in order to improve wettability. During in vitro biological evaluation study, it was observed that SaOS-2 cells had high attachment on collagen-coated scaffolds. Significant improvement in cell proliferation and alkaline phosphatase activity for HA-incorporated composite scaffolds was observed due to the incorporation of HA. After 3 and 7 days of culture on all scaffolds, SaOS-2 cells also had normal morphology and growth. These results indicated that PHBV/PLLA-based scaffolds fabricated via an emulsion freezing/freeze-drying technique were favorable sites for osteoblastic cells and are promising for the applications of bone tissue engineering.

  2. Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra

    Directory of Open Access Journals (Sweden)

    H. Beydoun

    2016-10-01

    Full Text Available Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS density (ns often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown

  3. Separation of glucose and fructose by freezing crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.T.C.R.; Martinez, K.C.L. [Federal University of Sao Carlos, Chemical Engineering Department, Industrial Crystallization Laboratory - Rod. Washington Luis km 235, P.O. Box 676, CEP:13565-905, Sao Carlos-SP (Brazil); Brito, A.B.N. [Federal University of Espirito Santo, Engineering and Computing Dept. - Rodovia BR 101 Norte, Km. 60, Bairro Litoraneo, CEP 29932-540, Sao Mateus-ES (Brazil); Giulietti, M. [Laboratory of Chemical Process and Particle Technology of Institute for Technological Research, Av. Prof. Almeida Prado 532 -Universitary City, CEP:05508-901, Sao Paulo-SP (Brazil)

    2010-10-15

    This work comprises the implementation of a methodology for the study of an industrial crystallization process by freezing and cooling to be applied in the separation of sugars with industrial relevance (glucose and fructose). The main interest is the production of fructose. This sugar is obtained by sucrose hydrolysis in acidic solutions, which yields an equimolar mixture of glucose and fructose. The developed separation process is based on the solubility difference between the sugars. Experiments were carried out in a jacketed glass crystallizer where the solution coming from the sucrose acid inversion was submitted to a slow cooling. Since glucose has lower solubility than fructose, it crystallizes in the bulk as the temperature is lowered, thus it can be removed from the solution by filtration or centrifugation. Best fructose-glucose separation was achieved for a total sugar concentration of 50 wt%. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Analysis for Difficulty during Freeze-Drying Feizixiao Lychees

    Directory of Open Access Journals (Sweden)

    L. L. Huang

    2017-01-01

    Full Text Available Compared to other cultivar lychees, volume density of Feizixiao lychee was higher due to serious shrinkage during freeze-drying (FD. Guiwei lychee and Nuomici lychee were used for comparison in order to illuminate the reason of the aforementioned phenomenon. Lower prefreezing temperature could not improve the volume density of Feizixiao lychee. Microstructure results show that pulp cell of Feizixiao lychee (tail was smaller and more compact than Guiwei and Nuomici lychee pulp cell. In addition, there is a membrane around the surface of Feizixiao lychee pulp. And the microstructure of Feizixiao lychee tip pulp cell is different from tail pulp cell. Membrane and tip pulp cell are both smaller and more compact than tail pulp cell. These structure differences hinder the moisture removing of Feizixiao lychee during FD. Removing the membrane and tip pulp could not improve the volume density of Feizixiao lychee. Ultrasound treatment for 30 min could significantly enhance the volume density of Feizixiao lychee.

  5. MICROSTRUCTURE MODIFICATIONS INDUCED IN SPRUCE WOOD BY FREEZING

    Directory of Open Access Journals (Sweden)

    Maria Bernadett SZMUTKU

    2011-12-01

    Full Text Available Scanning Electron Microscopy (SEM is amodern, non-invasive method for objective andspecialized image analysis of anatomical materialfeatures at microscopic level. Referring to wood, itoffers the possibility to view in 3D a bunch ofneighboring cells, in all three grain directions.This allows the imaging of modifications thatmight appear in the structure of the wood cellmembrane (e.g. micro-fissures caused by differentfactors, including temperature variations. This paperpresents the results of the SEM analysis performedon European spruce (Picea abies samples, cut fromboards which were subjected to freezing and thawingunder different conditions of temperature variationand time of exposure.The main aim of this research was to reveal theconditions which determine the occurrence of microfissuresin the cell wall and consequently lead tostrength losses in wood.

  6. Freezing heat transfer within water-saturated porous media

    International Nuclear Information System (INIS)

    Sasaki, Akira; Aiba, Shinya; Fukusako, Shoichiro.

    1990-01-01

    In the present study, analytical and experimental investigations were performed so as to clarify the characteristics of freezing heat transfer in porous media saturated with water in a vertical rectangular cavity. In order to establish the momentum equation, the law of conservation of momentum was applied to the fluid in our control volume, and the equation took into account Forchheimer's extension as the resistance to flow in the porous media. Three different sizes of glass, iron and copper beads were used as the porous media in this study. The temperature of the cold wall was kept at -10degC, while that of the hot wall was varied from 2degC to 22 degC. Comparisons between the analytical results and the experimental ones show good agreement with the exception of the copper bead results. (author)

  7. Freeze-Casting of Porous Biomaterials: Structure, Properties and Opportunities

    Directory of Open Access Journals (Sweden)

    Sylvain Deville

    2010-03-01

    Full Text Available The freeze-casting of porous materials has received a great deal of attention during the past few years. This simple process, where a material suspension is simply frozen and then sublimated, provides materials with unique porous architectures, where the porosity is almost a direct replica of the frozen solvent crystals. This review focuses on the recent results on the process and the derived porous structures with regards to the biomaterials applications. Of particular interest is the architecture of the materials and the versatility of the process, which can be readily controlled and applied to biomaterials applications. A careful control of the starting formulation and processing conditions is required to control the integrity of the structure and resulting properties. Further in vitro and in vivo investigations are required to validate the potential of this new class of porous materials.

  8. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    Science.gov (United States)

    Ungar, Eugene K.; Schunk, Richard G.

    2011-01-01

    An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

  9. The principles of ultrasound and its application in freezing related processes of food materials: A review.

    Science.gov (United States)

    Cheng, Xinfeng; Zhang, Min; Xu, Baoguo; Adhikari, Benu; Sun, Jincai

    2015-11-01

    Ultrasonic processing is a novel and promising technology in food industry. The propagation of ultrasound in a medium generates various physical and chemical effects and these effects have been harnessed to improve the efficiency of various food processing operations. Ultrasound has also been used in food quality control as diagnostic technology. This article provides an overview of recent developments related to the application of ultrasound in low temperature and closely related processes such as freezing, thawing, freeze concentration and freeze drying. The applications of high intensity ultrasound to improve the efficiency of freezing process, to control the size and size distribution of ice crystals and to improve the quality of frozen foods have been discussed in considerable detail. The use of low intensity ultrasound in monitoring the ice content and to monitor the progress of freezing process has also been highlighted. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Limited Impact of Subglacial Supercooling Freeze-on for Greenland Ice Sheet Stratigraphy

    Science.gov (United States)

    Dow, Christine F.; Karlsson, Nanna B.; Werder, Mauro A.

    2018-02-01

    Large units of disrupted radiostratigraphy (UDR) are visible in many radio-echo sounding data sets from the Greenland Ice Sheet. This study investigates whether supercooling freeze-on rates at the bed can cause the observed UDR. We use a subglacial hydrology model to calculate both freezing and melting rates at the base of the ice sheet in a distributed sheet and within basal channels. We find that while supercooling freeze-on is a phenomenon that occurs in many areas of the ice sheet, there is no discernible correlation with the occurrence of UDR. The supercooling freeze-on rates are so low that it would require tens of thousands of years with minimal downstream ice motion to form the hundreds of meters of disrupted radiostratigraphy. Overall, the melt rates at the base of the ice sheet greatly overwhelm the freeze-on rates, which has implications for mass balance calculations of Greenland ice.

  11. Comparison Study of Three Common Technologies for Freezing-Thawing Measurement

    Directory of Open Access Journals (Sweden)

    Xinbao Yu

    2010-01-01

    Full Text Available This paper describes a comparison study on three different technologies (i.e., thermocouple, electrical resistivity probe and Time Domain Reflectometry (TDR that are commonly used for frost measurement. Specially, the paper developed an analyses procedure to estimate the freezing-thawing status based on the dielectric properties of freezing soil. Experiments were conducted where the data of temperature, electrical resistivity, and dielectric constant were simultaneously monitored during the freezing/thawing process. The comparison uncovered the advantages and limitations of these technologies for frost measurement. The experimental results indicated that TDR measured soil dielectric constant clearly indicates the different stages of the freezing/thawing process. Analyses method was developed to determine not only the onset of freezing or thawing, but also the extent of their development. This is a major advantage of TDR over other technologies.

  12. Microstructure study of a material on the basis of YSZ obtained be freeze-drying

    International Nuclear Information System (INIS)

    Rizea, A.; Abrudeanu, M.; Petot, C.; Petot Ervas, G.

    2001-01-01

    Freeze-drying is a dehydration proceeding of the products in a frozen state, which is based on the ice sublimation process. It is a method, which leads to a very good homogeneity of the products and it allows obtaining very fine powders, which directs to reducing the sintering temperature. Freeze drying always supposes three stages: - freezing, sublimation and absorption of the residual water. The preparation of ZrO 20.91 Y 2 O 30.09 samples proceeds through the following stages: - a. solution preparation; b. solution spraying (into small droplets in liquid nitrogen); c. freeze drying processing; d. calcination of the freeze dried powder; e. powder compacting; f. sintering at four different temperature. The different structure of samples with different density are characterized on basis of micrographs. The results of these analyses are presented, discussed and explained through the chemical composition of the samples

  13. Freeze-drying-induced changes in the properties of graphene oxides

    International Nuclear Information System (INIS)

    Ham, Heon; Van Khai, Tran; Gil Na, Han; Jung Kwon, Yong; Yeon Cho, Hong; Woo Kim, Hyoun; Park, No-Hyung; So, Dae Sup; Lee, Joon-Woo

    2014-01-01

    We have characterized and evaluated changes in graphene oxide (GO) induced by means of freeze-drying. In order to evaluate these changes, we investigated the effects of freeze-drying and chemical reduction processes on the structure, morphology, chemical composition, and Raman properties of GO and reduced GO. The freeze-dried GO had a pore structure, maintaining a pored morphology even after thermal annealing. The freeze-dried samples were composed of a single folded nanosheet or a few nanosheets stacked and folded. The oxygen-containing functional groups were removed not only during the freeze-drying but also during the reduction processes, with an accompanying decrease in the average size of the sp 2 carbon domain (i.e. an increase in the I D /I G value). (papers)

  14. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    DEFF Research Database (Denmark)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin

    2016-01-01

    -freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC...... concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax...... component 4 (EXmax: 280 nm, EXmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties...

  15. Evaluation and Comparison of Freeze-Thaw Tests and Air Void Analysis of Pervious Concrete

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Kevern, John T.

    2016-01-01

    Pearl-Chain Bridge technology is an innovative precast arch bridge solution which uses pervious concrete as fill material. To ensure longevity of the bridge superstructure it is necessary that the per-vious concrete fill is designed to be freeze-thaw durable; however, no standards exist on how...... to eval-uate the freeze-thaw resistance of fresh or hardened pervious concrete and correspondingly what constitutes acceptable freeze-thaw durability. A greater understanding of the correlation between the freeze-thaw performance and the air void structure of pervious concrete is needed. In the present...... study six pervious concrete mixes were exposed to freeze-thaw testing, and their air void structure was analyzed using an automated linear-traverse method. It was found that there is a miscorrelation between these two test methods in their assumption of whether or not the large interconnected voids...

  16. Evaluation of freeze-thaw durability of pervious concrete by use of operational modal analysis

    DEFF Research Database (Denmark)

    Lund, M.S.M.; Hansen, K. K.; Brincker, R.

    2018-01-01

    It is well-known that laboratory testing of pervious concrete's freeze-thaw performance is too harsh and does not agree well with field observations. The most commonly used laboratory freeze-thaw test method for pervious concrete is similar to that used for conventional concrete even though...... the void structure of the two materials is completely different. In the present study, a new freeze-thaw test method for pervious concrete is suggested and tested on one baseline mix, with three different contents of entrained air. The evaluation of freeze-thaw damage on pervious concrete beams...... was evaluated from the decrease in mass and from operational modal analysis which provides an accurate determination of the change in natural frequencies with freeze-thaw exposure. Operational modal analysis was also used to determine the Young's modulus, shear modulus, and Poisson's ratio of the pervious...

  17. Evaluation of Freezing Damage in some Pistachio Seedling Rootstocks

    Directory of Open Access Journals (Sweden)

    Maryam Afrousheh

    2018-06-01

    Full Text Available A greenhouse experiment was conducted to evaluate the freezing damage in some pistachio rootstocks by ion leakage and pH changes of leaked solution. A factorial experiment was carried out in randomized block designs (RBD with three factors: Temperature (A including 4 ̊C, 0 ̊C, -2 ̊C, -4 ̊C, -6 ̊C, Time (B including 3, 12, 24h , and Rootstock (C including P. vera cv 'Badami Zarand' (V13 and 'Sarakhs' (S5, P. mutica (M1and P. atlantica (A7. For this, one-year-old seedlings were kept at these five temperatures in incubator for 2 hours. Then in the first 24 hours in three hour intervals and during four days, EC and pH in leaked solution were measured daily. After four days the seedling samples were autoclaved at temperatures 105°C for 4 minutes to destroy all cell membrane. EC and pH of remaining solution were measured again and the percentage of ionic leakage was calculated. The results showed that the best time to evaluate the pH and ionic leakage was 24 hours after incubation of samples. Based on the results, ionic leakage dramatically increased with decreasing temperatures from 0°C to -6°C, while pH of leaked solution had no significant difference in 0°C and 4°C temperature treatments. When temperature reduced from 0°C to -6°C, like ionic leakage, pH greatly reduced. So the pH of the leaked solution could be an appropriate tool to study the freezing damage of pistachio rootstocks. Based on the results of pH and ionic leakage, P. mutica and P. atlantica were the most frost tolerant and sensitive rootstocks of this experiment, respectively.

  18. Diagnosing and curing system freeze-ups: Part II

    Energy Technology Data Exchange (ETDEWEB)

    Frey, R. [Heating and Plumbing Service, Sparta, NJ (United States)

    1996-02-01

    In our last article, we discussed determination and possible causes leading to frozen pipes in the heating system. We now turn to the matter of dealing with such freeze-ups. There are two major categories of frozen heating systems. The first and worst we can label the {open_quotes}Floridian Flew{close_quotes} type, when the usual occupants have taken off for warmer climates. The second is the {open_quotes}Howcudit {open_quote}B{close_quote} virus,{close_quotes} which occurs to normal people under an unusual Arctic Attack right while they are living there. Regarding the first, I never cease to be amazed how folks can just up and leave their house for three days to three months without making proper arrangements for monitoring the temperature of their home during their absence. There are a frightening number of humanoids out there, who either lack a minimal presence of common sense, or who are terrible gamblers. The amazing thing is that some of these folks wouldn`t even gamble a postage stamp on a magazine sweepstakes, but still will gamble the contents of their home by driving off for two weeks at Disneyland in the middle of January without ever making any provision for assuring that their house doesn`t freeze up while they are away. The {open_quotes}Howcudit {open_quote}B{close_quote}{close_quotes} type is not nearly as devasting as the {open_quotes}Floridian Flew.{close_quotes} Imagine coming home to an icy cold house after flying in from the sunny beaches of some tropical paradise. The oilburner switch is on. The thermostate is set at 60 where we left it, but the needle is buried somewhere down behind the cover, like it is cowering from guilt. {open_quotes}Oh Man! I just checked the bathroom; there is an icicle hanging from the vanity faucet and the toilet bowl is a block of ice.{close_quotes}

  19. Development of freeze-dried miyeokguk, Korean seaweed soup, as space food sterilized by irradiation

    International Nuclear Information System (INIS)

    Song, Beom-Seok; Park, Jin-Gyu; Kim, Jae-Hun; Choi, Jong-Il; Ahn, Dong-Hyun; Hao, Chen; Lee, Ju-Woon

    2012-01-01

    The purpose of this study was to evaluate microbial populations, Hunter's color values (L ⁎ , a ⁎ , b ⁎ ) and the sensory quality of freeze-dried miyeokguk, Korean seaweed soup, in order to use it as space food. Microorganisms were not detected in non-irradiated freeze-dried miyeokguk within the detection limit of 1.00 log CFU/g. However, the microbial population in rehydrated miyeokguk was 7.01 log CFU/g after incubation at 35 °C for 48 h, indicating that freeze-dried miyeokguk was not sterilized by heat treatment during the preparation process. Bacteria in the freeze-dried miyeokguk were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei, and Ancinetobacter genomosp. using the 16S rDNA sequencing. In samples that were gamma-irradiated above 10 kGy, it was confirmed that all microorganisms were inactivated. Hunter's color values of the samples irradiated at doses less than 10 kGy were not significantly altered from their baseline appearance (p>0.05). Sensory evaluation showed that preference scores in all sensory properties decreased when freeze-dried miyeokguk was irradiated at doses greater than 10 kGy. Therefore, the results of this study suggest that gamma irradiation at 10 kGy is sufficient to sterilize freeze-dried miyeokguk without significant deterioration in the sensory quality, and thus, the freeze-dried and irradiated miyeokguk at 10 kGy fulfills the microbiological requirements as space food. - Highlights: ► 10 kGy gamma-irradiation is sufficient for sterilization of freeze-dried miyeokguk. ► Sensory quality of freeze-dried miyeokguk decreased after >10 kGy gamma irradiation. ► 10 kGy gamma-irradiation sterilizes freeze-dried miyeokguk and makes it optimal for use as space food.

  20. Chlorophyll fluorescence imaging accurately quantifies freezing damage and cold acclimation responses in Arabidopsis leaves

    Directory of Open Access Journals (Sweden)

    Hincha Dirk K

    2008-05-01

    Full Text Available Abstract Background Freezing tolerance is an important factor in the geographical distribution of plants and strongly influences crop yield. Many plants increase their freezing tolerance during exposure to low, nonfreezing temperatures in a process termed cold acclimation. There is considerable natural variation in the cold acclimation capacity of Arabidopsis that has been used to study the molecular basis of this trait. Accurate methods for the quantitation of freezing damage in leaves that include spatial information about the distribution of damage and the possibility to screen large populations of plants are necessary, but currently not available. In addition, currently used standard methods such as electrolyte leakage assays are very laborious and therefore not easily applicable for large-scale screening purposes. Results We have performed freezing experiments with the Arabidopsis accessions C24 and Tenela, which differ strongly in their freezing tolerance, both before and after cold acclimation. Freezing tolerance of detached leaves was investigated using the well established electrolyte leakage assay as a reference. Chlorophyll fluorescence imaging was used as an alternative method that provides spatial resolution of freezing damage over the leaf area. With both methods, LT50 values (i.e. temperature where 50% damage occurred could be derived as quantitative measures of leaf freezing tolerance. Both methods revealed the expected differences between acclimated and nonacclimated plants and between the two accessions and LT50 values were tightly correlated. However, electrolyte leakage assays consistently yielded higher LT50 values than chlorophyll fluorescence imaging. This was to a large part due to the incubation of leaves for electrolyte leakage measurements in distilled water, which apparently led to secondary damage, while this pre-incubation was not necessary for the chlorophyll fluorescence measurements. Conclusion Chlorophyll

  1. Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers.

    Science.gov (United States)

    Pittermann, Jarmila; Sperry, John

    2003-09-01

    We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-thaw cycle at -0.5 MPa in a centrifuge. Embolism increased as mean tracheid diameter exceeded 30 microm. Tracheids with a critical diameter greater than 43 microm were calculated to embolize in response to freezing and thawing at a xylem pressure of -0.5 MPa. To confirm that freezing-induced embolism is a function of conduit air content, we air-saturated stems of Abies lasiocarpa (Hook.) Nutt. (mean conduit diameter 13.7 +/- 0.7 microm) by pressurizing them 1 to 60 times above atmospheric pressure, prior to freezing and thawing. The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure. Embolism increased when the dissolved air content was equivalent to a mean tracheid diameter of 30 microm at ambient air pressure. Our centrifuge and air-saturation data show that conifers are as vulnerable to freeze-thaw embolism as angiosperms with equal conduit diameter. We suggest that the hydraulic conductivity of conifer wood is maximized by increasing tracheid diameters in locations where freezing is rare. Conversely, the narrowing of tracheid diameters protects against freezing-induced embolism in cold climates.

  2. The freezing point of raw and heat treated sheep milk and its variation during lactation

    Directory of Open Access Journals (Sweden)

    Bohumíra Janštová

    2013-01-01

    Full Text Available The freezing point of milk is an important indicator of the adulteration of the milk with water, but heat treatment may also affect its value. The aim of this study was determine freezing point of raw and heat treated sheep milk and its variation during lactation. The freezing point was determined in 42 bulk tank raw sheep milk samples and 42 pasteurized milk samples collected during lactation of sheep at one ecofarm in Moravian Walachia (Valašsko in the Czech Republic. The freezing point was determined in accordance with the standard ČSN 57 0538 using a thermistor cryoscope. The average freezing point of raw milk was -0.617 ± 0.052 °C, with a range from -0.560 to -0.875 °C. The freezing point was lower in the first months of lactation and increased at the end of lactation. The freezing point correlated (r = 0.8967 with the content of total non-fat solids. The average freezing point of sheep milk pasteurized at 65 °C for 30 min was -0.614 ± 0.053 °C, with a range from -0.564 to -0.702 °C. The median of freezing point differences between raw and pasteurized milk was 0.004 °C. Our study extends data about physico-chemical properties of sheep milk and registers for the first time specific changes in the freezing point value of sheep milk by heating.

  3. Freeze-drying of mononuclear cells derived from umbilical cord blood followed by colony formation.

    Directory of Open Access Journals (Sweden)

    Dity Natan

    Full Text Available BACKGROUND: We recently showed that freeze-dried cells stored for 3 years at room temperature can direct embryonic development following cloning. However, viability, as evaluated by membrane integrity of the cells after freeze-drying, was very low; and it was mainly the DNA integrity that was preserved. In the present study, we improved the cells' viability and functionality after freeze-drying. METHODOLOGY/PRINCIPAL FINDINGS: We optimized the conditions of directional freezing, i.e. interface velocity and cell concentration, and we added the antioxidant EGCG to the freezing solution. The study was performed on mononuclear cells (MNCs derived from human umbilical cord blood. After freeze-drying, we tested the viability, number of CD34(+-presenting cells and ability of the rehydrated hematopoietic stem cells to differentiate into different blood cells in culture. The viability of the MNCs after freeze-drying and rehydration with pure water was 88%-91%. The total number of CD34(+-presenting cells and the number of colonies did not change significantly when evaluated before freezing, after freeze-thawing, and after freeze-drying (5.4 x 10(4+/-4.7, 3.49 x 10(4+/-6 and 6.31 x 10(4+/-12.27 cells, respectively, and 31+/-25.15, 47+/-45.8 and 23.44+/-13.3 colonies, respectively. CONCLUSIONS: This is the first report of nucleated cells which have been dried and then rehydrated with double-distilled water remaining viable, and of hematopoietic stem cells retaining their ability to differentiate into different blood cells.

  4. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Science.gov (United States)

    McGill, Lorraine M; Shannon, Adam J; Pisani, Davide; Félix, Marie-Anne; Ramløv, Hans; Dix, Ilona; Wharton, David A; Burnell, Ann M

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent "ecological fitting

  5. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Directory of Open Access Journals (Sweden)

    Lorraine M McGill

    Full Text Available Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent

  6. Chemical freeze out condition for central heavy-ion collisions at AGS, SPS, RHIC and LHC energies

    International Nuclear Information System (INIS)

    Chatterjee, Sandeep; Mishra, Debadeepti; Mohanty, Bedangadas; Das, Sabita; Sharma, Natasha; Kumar, Lokesh; Sahoo, Raghunath

    2014-01-01

    As a result of ultrarelativistic collision between two heavy ions, a fireball is expected to form that rapidly thermalized as it expands and hence cools. As the interparticle separation increases the particles cease to interact. The surface of last scattering is the freeze-out surface. It can be of two types: chemical freeze-out (CFO) where inelastic collisions cease and kinetic freeze-out where elastic collisions cease. But in general freeze-out can be a more complicated process in which different types of particles and reactions switch-off at different times giving rise to a series of freeze-out surfaces. Here we will discuss two CFO schemes: 1CFO, in which all hadrons freeze-out together and 2CFO, in which all strange and those with hidden strangeness freeze-out at the same surface and the other non strange hadrons freeze-out at a separate surface

  7. 40 CFR Appendix B to Subpart G of... - Substitutes Subject to Use Restrictions and Unacceptable Substitutes

    Science.gov (United States)

    2010-07-01

    ... demonstrate it can be used safely in this end-use. CFC-12 Motor Vehicle Air Conditioners (Retrofit and New... Conditions Application Substitute Decision Conditions Comments CFC-12 Automobile Motor Vehicle Air... refrigerant. CFC-12 Automobile Motor Vehicle Air Conditioning (New equipment only) R-152a as a substitute for...

  8. Optimal ordering quantities for substitutable deteriorating items under joint replenishment with cost of substitution

    Science.gov (United States)

    Mishra, Vinod Kumar

    2017-09-01

    In this paper we develop an inventory model, to determine the optimal ordering quantities, for a set of two substitutable deteriorating items. In this inventory model the inventory level of both items depleted due to demands and deterioration and when an item is out of stock, its demands are partially fulfilled by the other item and all unsatisfied demand is lost. Each substituted item incurs a cost of substitution and the demands and deterioration is considered to be deterministic and constant. Items are order jointly in each ordering cycle, to take the advantages of joint replenishment. The problem is formulated and a solution procedure is developed to determine the optimal ordering quantities that minimize the total inventory cost. We provide an extensive numerical and sensitivity analysis to illustrate the effect of different parameter on the model. The key observation on the basis of numerical analysis, there is substantial improvement in the optimal total cost of the inventory model with substitution over without substitution.

  9. [Contingency management in opioid substitution treatment].

    Science.gov (United States)

    Specka, M; Böning, A; Scherbaum, N

    2011-07-01

    The majority of opiate-dependent patients in substitution treatment show additional substance-related disorders. Concomitant use of heroin, alcohol, benzodiazepines or cocaine compromises treatment success. Concomitant drug use may be treated by using contingency management (CM) which is based on learning theory. In CM, abstinence from drugs, as verified by drug screenings, is reinforced directly and contingently. Reinforcers used in CM studies with substituted patients were, amongst others, vouchers and take-home privileges. Studies in the USA show a medium average effect of CM on drug consumption rates and abstinence. The effects decrease markedly after the end of the intervention. We discuss whether CM is applicable within the German substitution treatment system and how it can be combined with other interventions such as selective detoxification treatments or cognitive-behavioural programmes. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Biomaterials in search of a meniscus substitute.

    Science.gov (United States)

    Rongen, Jan J; van Tienen, Tony G; van Bochove, Bas; Grijpma, Dirk W; Buma, Pieter

    2014-04-01

    The menisci fulfill key biomechanical functions in the tibiofemoral (knee) joint. Unfortunately meniscal injuries are quite common and most often treated by (partial) meniscectomy. However, some patients experience enduring symptoms, and, more importantly, it leads to an increased risk for symptomatic osteoarthritis. Over the past decades, researchers have put effort in developing a meniscal substitute able to prevent osteoarthritis and treat enduring clinical symptoms. Grossly, two categories of substitutes are observed: First, a resorbable scaffold mimicking biomechanical function which slowly degrades while tissue regeneration and organization is promoted. Second, a non resorbable, permanent implant which mimics the biomechanical function of the native meniscus. Numerous biomaterials with different (material) properties have been used in order to provide such a substitute. Nevertheless, a clinically applicable cartilage protecting material is not yet emerged. In the current review we provide an overview, and discuss, these different materials and extract recommendations regarding material properties for future developmental research. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Substitution between Cars within the Household

    DEFF Research Database (Denmark)

    de Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

    In this paper we study the demand for car kilometres in two-car households, focusing on the substitution between cars in response to fuel price changes. We use a large sample of detailed Danish data on two-car households to estimate—for each car owned by the household—own and cross-price effects...... of increases in fuel costs per kilometre. The empirical results show that failure to capture substitution between cars within the household can result in substantial misspecification biases. Ignoring substitution, we estimate fuel price elasticities of –0.81 and -0.65 for the primary and secondary cars...... efficient car, finding partial support for the underlying hypothesis. More importantly, the results of this extended model emphasize the importance of behavioural differences related to the position of the most fuel efficient car in the household, suggesting that households’ fuel efficiency choices...

  12. Substitute energy resource policy in Japan

    International Nuclear Information System (INIS)

    Umehara, Katsuhiko

    1980-01-01

    Japan depends 88% of energy resources and 99.8% of petroleum on imports. The solution of energy problems is now made internationally. As the means for Japan, there are the substitution of other resources for petroleum and its promotion. However, this involves the considerable funds for the development and utilization, which must be borne by the people in the form of tax. For governmental financing, a special account must be set up for the particular purpose. In the research and development of new energy resources, new institution is required. The following matters are described: petroleum shortage coming even in 1980s, the international need of substitute energy development, the need for establishing measures for substitute energy resources, acquisition of the funds, special-account governmental financing, and an institute of new energy development. (author)

  13. Substituting telecommunications for travel - Feasible or desirable

    Science.gov (United States)

    Van Vleck, E. M.

    1974-01-01

    This paper reviews recent advances in telecommunications and examines the detailed structure of travel to estimate the feasibility of substituting telecommunications for various travel objectives. The impact of travel is analyzed from a social, economic, energy, and pollution standpoint to assess the desirability of substitution. Perhaps 35-50% of the nation's travel could, in theory, be replaced by very advanced telecommunications (such as a much improved large-screen teleconferencing network), but public resistance would be massive. Much economic dislocation would result since, for example, over 25% of retail sales are travel-related. The energy savings would be modest since only 25% of the nation's energy is consumed by transportation. However, all pollution would be reduced substantially since transportation accounts for 75% of the carbon monoxide, 60% of the hydrocarbon, and 55% of the nitrogen oxide pollution in the nation. Problems related to the implementation of large-scale substitution are discussed.

  14. The genetic characteristics in cytology and plant physiology of two wheat (Triticum aestivum) near isogenic lines with different freezing tolerances.

    Science.gov (United States)

    Wang, Wenqiang; Hao, Qunqun; Wang, Wenlong; Li, Qinxue; Wang, Wei

    2017-11-01

    Freezing tolerance in taft plants relied more upon an ABA-independent- than an ABA-dependent antifreeze signaling pathway. Two wheat (Triticum aestivum) near isogenic lines (NIL) named tafs (freezing sensitivity) and taft (freezing tolerance) were isolated in the laboratory and their various cytological and physiological characteristics under freezing conditions were studied. Proplastid, cell membrane, and mitochondrial ultrastructure were less damaged by freezing treatment in taft than tafs plants. Chlorophyll, ATP, and thylakoid membrane protein contents were significantly higher, but malondialdehyde content was significantly lower in taft than tafs plants under freezing condition. Antioxidant capacity, as indicated by reactive oxygen species accumulation and antioxidant enzyme activity, and the relative gene expression were significantly greater in taft than tafs plants. Soluble sugars and abscisic acid (ABA) contents were significantly higher in taft plants than in tafs plants under both normal and freezing conditions. The upregulated expression levels of certain freezing tolerance-related genes were greater in taft than tafs plants under freezing treatment. The addition of sodium tungstate, an ABA synthesis inhibitor, led to only partial freezing tolerance inhibition in taft plants and the down-regulated expression of some ABA-dependent genes. Thus, both ABA-dependent and ABA-independent signaling pathways are involved in the freezing tolerance of taft plants. At the same time, freezing tolerance in taft plants relied more upon an ABA-independent- than an ABA-dependent antifreeze signaling pathway.

  15. Comparative study of the sensibility of Metacercaria cysts of Phagicola Faust, 1920 (Trematoda: Heterophyidae) to ionizing radiation and to freezing in raw mullets Mugil Linnaeus, 1758 (Pisces: Mugilidae)

    International Nuclear Information System (INIS)

    Moraes, Ivany Rodrigues de

    2005-01-01

    Foodborne illnesses have been a growing concern to the governments, international organizations and consumers, mainly regarding the damages they cause to human health. This issue is the result of the substitution of imported food habits, which enable the consumption of raw fish or wrongly prepared fish. Among the emergent parasitic zoonosis, the Fagicolose stands out. It is transmitted by Phagicola longa, a trematoda of great importance in public health and responsible for high percentages of Mugilidae infections, that is able to produce humans' parasitism. In this experiment, the studies were focused to the radio sensibility of metacercaria of Phagicola longa exposed to a treatment with ionizing radiation (gamma rays and electron beams) and the sensibility to freezing, in artificially infected fish. Some data were acquired regarding the occurrence of Phagicola longa in mullets bought in the local market, the freezer temperature of 10 domestic refrigerators, and the origin and preservation of the mullets in some Japanese-type restaurants in Sao Paulo. The results indicated more effectiveness in the treatment with the electron accelerator, as well as with the freezing at the temperature of-16 deg C. (author)

  16. A New Substitution Cipher - Random-X

    Directory of Open Access Journals (Sweden)

    Falguni Patel

    2015-08-01

    Full Text Available Ciphers are the encryption methods to prepare the algorithm for encryption and decryption. The currently known ciphers are not strong enough to protect the data. A new substitution cipher Random-X that we introduce in this paper can be used for password encryption and data encryption. Random-X cipher is a unique substitution cipher which replaces the units of plaintext with triplets of letters. The beauty of this cipher is that the encrypted string of the same plain text is not always same. This makes it strong and difficult to crack. This paper covers the principle the implementation ideas and testing of Random-X cipher.

  17. Hydrophosphorylation of substituted alkynes by phosphonic acids

    International Nuclear Information System (INIS)

    Nifant'ev, E.F.; Solovetskaya, L.A.; Maslennikova, V.I.; Sergeev, N.M.

    1987-01-01

    Hydrophosphorylation of functionally substituted alkynes by phosphonic acids can be a convenient method for synthesis of functionally substituted mono- and diphosphine oxides. The ease of hydrophosphorylation is determined by the strength of the negative inductive effect of the substituents on the triple bond and the steric factor. The structure of the bis-adducts was confirmed by elementary analysis and the 31 P and 13 C NMR spectra. The 31 P NMR spectrum is an AB two-spin system. The values of the chemical shifts and spin-spin interaction constants 3 J/sub PP/ are in agreement with the data in the literature for similar compounds

  18. Substitution between cars within the household

    DEFF Research Database (Denmark)

    De Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

    The purpose of this paper is to study to what extent two-car households substitute the use of their less fuel efficient car by the use of their more fuel efficient car after an increase in fuel prices. Based on a simple theoretical framework we use a large sample of detailed Danish data on two-car...... households to estimate, for each car owned by the household, own and cross-price effects of increases in fuel costs per kilometer. The empirical results point at important substitution effects, so that models that estimate responses to fuel prices on the implicit or explicit assumption of one car per...

  19. A Case of Apparent Upper-Body Freezing in Parkinsonism while Using a Wheelchair

    Directory of Open Access Journals (Sweden)

    Samuel T. Nemanich

    2017-05-01

    Full Text Available Freezing of gait (FOG is a common, disabling gait disturbance in Parkinson’s disease (PD and other Parkinsonian syndromes. Freezing also occurs during non-gait movements involving the upper limbs. The mechanisms underlying freezing are complex, likely involving motor, cognitive, and sensory systems that contribute to the episodes. Here, we reported a 60-year-old female with a 24-year history of parkinsonism who experienced significant FOG when ambulatory. Disease progression resulted in her permanent use of a powered wheelchair. While using the power chair, the patient experiences apparent paroxysmal freezing in the hand and arm used to steer and propel the chair. These episodes, some lasting up to several minutes, occur only in circumstances (e.g., entering and leaving an elevator that are similar to environments known to elicit and exacerbate FOG. Episodes are transient and can be volitionally interrupted by the patient but sometimes require external assistance. Therapeutic intervention for this type of potential freezing has yet to be determined. This case may provide insight into the complex nature of freezing behavior and suggests a need for new approaches to treating non-traditional freezing behavior.

  20. Development of Three-Layer Simulation Model for Freezing Process of Food Solution Systems

    Science.gov (United States)

    Kaminishi, Koji; Araki, Tetsuya; Shirakashi, Ryo; Ueno, Shigeaki; Sagara, Yasuyuki

    A numerical model has been developed for simulating freezing phenomena of food solution systems. The cell model was simplified to apply to food solution systems, incorporating with the existence of 3 parts such as unfrozen, frozen and moving boundary layers. Moreover, the moving rate of freezing front model was also introduced and calculated by using the variable space network method proposed by Murray and Landis (1957). To demonstrate the validity of the model, it was applied to the freezing processes of coffee solutions. Since the model required the phase diagram of the material to be frozen, the initial freezing temperatures of 1-55 % coffee solutions were measured by the DSC method. The effective thermal conductivity for coffee solutions was determined as a function of temperature and solute concentration by using the Maxwell - Eucken model. One-dimensional freezing process of 10 % coffee solution was simulated based on its phase diagram and thermo-physical properties. The results were good agreement with the experimental data and then showed that the model could accurately describe the change in the location of the freezing front and the distributions of temperature as well as ice fraction during a freezing process.

  1. Non-Toxic, Low-Freezing, Drop-In Replacement Heat Transfer Fluids

    Science.gov (United States)

    Cutbirth, J. Michael

    2012-01-01

    A non-toxic, non-flammable, low-freezing heat transfer fluid is being developed for drop-in replacement within current and future heat transfer loops currently using water or alcohol-based coolants. Numerous water-soluble compounds were down-selected and screened for toxicological, physical, chemical, compatibility, thermodynamic, and heat transfer properties. Two fluids were developed, one with a freezing point near 0 C, and one with a suppressed freezing point. Both fluids contain an additive package to improve material compatibility and microbial resistance. The optimized sub-zero solution had a freezing point of 30 C, and a freezing volume expansion of 10-percent of water. The toxicity of the solutions was experimentally determined as LD(50) greater than 5g/kg. The solutions were found to produce minimal corrosion with materials identified by NASA as potentially existing in secondary cooling loops. Thermal/hydrodynamic performance exceeded that of glycol-based fluids with comparable freezing points for temperatures Tf greater than 20 C. The additive package was demonstrated as a buffering agent to compensate for CO2 absorption, and to prevent microbial growth. The optimized solutions were determined to have physically/chemically stable shelf lives for freeze/thaw cycles and longterm test loop tests.

  2. Effects of annealing on the physical properties of therapeutic proteins during freeze drying process.

    Science.gov (United States)

    Lim, Jun Yeul; Lim, Dae Gon; Kim, Ki Hyun; Park, Sang-Koo; Jeong, Seong Hoon

    2018-02-01

    Effects of annealing steps during the freeze drying process on etanercept, model protein, were evaluated using various analytical methods. The annealing was introduced in three different ways depending on time and temperature. Residual water contents of dried cakes varied from 2.91% to 6.39% and decreased when the annealing step was adopted, suggesting that they are directly affected by the freeze drying methods Moreover, the samples were more homogenous when annealing was adopted. Transition temperatures of the excipients (sucrose, mannitol, and glycine) were dependent on the freeze drying steps. Size exclusion chromatography showed that monomer contents were high when annealing was adopted and also they decreased less after thermal storage at 60°C. Dynamic light scattering results exhibited that annealing can be helpful in inhibiting aggregation and that thermal storage of freeze-dried samples preferably induced fragmentation over aggregation. Shift of circular dichroism spectrum and of the contents of etanercept secondary structure was observed with different freeze drying steps and thermal storage conditions. All analytical results suggest that the physicochemical properties of etanercept formulation can differ in response to different freeze drying steps and that annealing is beneficial for maintaining stability of protein and reducing the time of freeze drying process. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Effect of Novel Quick Freezing Techniques Combined with Different Thawing Processes on Beef Quality

    Science.gov (United States)

    Yoo, Seon-Mi; Han, Gui-Jung

    2014-01-01

    This study investigated the effect of various freezing and thawing techniques on the quality of beef. Meat samples were frozen using natural convection freezing (NF), individual quick freezing (IQF), or cryogenic freezing (CF) techniques, followed by natural convection thawing (NCT) or running water thawing (RT). The meat was frozen until the core temperature reached -12℃ and then stored at -24℃, followed by thawing until the temperature reached 5℃. Quality parameters, such as the pH, water binding properties, CIE color, shear force, and microstructure of the beef were elucidated. Although the freezing and thawing combinations did not cause remarkable changes in the quality parameters, rapid freezing, in the order of CF, IQF, and NF, was found to minimize the quality deterioration. In the case of thawing methods, NCT was better than RT and the meat quality was influence on the thawing temperature rather than the thawing rate. Although the microstructure of the frozen beef exhibited an excessive loss of integrity after the freezing and thawing, it did not cause any remarkable change in the beef quality. Taken together, these results demonstrate that CF and NCT form the best combination for beef processing; however, IQF and NCT may have practical applications in the frozen food industry. PMID:26761674

  4. Social Freezing in Medical Practice. Experiences and Attitudes of Gynecologists in Germany.

    Science.gov (United States)

    Schochow, Maximilian; Rubeis, Giovanni; Büchner-Mögling, Grit; Fries, Hansjakob; Steger, Florian

    2017-09-09

    Surveys of the German public have revealed a high acceptance of social freezing, i.e. oocyte conservation without medical indication. Up to now, there are no investigations available on the experiences and attitudes of health professionals towards social freezing. Between August 2015 and January 2016, we surveyed gynecologists Germany-wide on the topic social freezing. Five gynecologists specialized in reproductive medicine and five office-based gynecologists in standard care were chosen for the survey. The survey was conducted with an explorative, qualitative research design. The demand for social freezing in Germany is low. With regard to their fertility age, most women attend consultations too late, they have only little previous knowledge and false expectations. The gynecologists consider it the duty of society and politics to provide for the compatibility of family and work. They relate late parenthood to disadvantages primarily for the children. A majority of the gynecologists interviewed tend to advise natural reproduction. Social freezing is often mistaken as a kind of fertility insurance. Thus, it is necessary that physicians inform women early about the possibilities and limitations of social freezing. In the first place, social freezing is not a medical or medical-ethical topic. Women consider the method as a possibility to ensure the compatibility of family and work. This compatibility should be mostly perceived as a political topic. It cannot be a medical task to solve this issue. In fact, a debate in society as a whole is necessary that includes all relevant actors.

  5. Development of freeze-dried miyeokguk, Korean seaweed soup, as space food sterilized by irradiation

    Science.gov (United States)

    Song, Beom-Seok; Park, Jin-Gyu; Kim, Jae-Hun; Choi, Jong-Il; Ahn, Dong-Hyun; Hao, Chen; Lee, Ju-Woon

    2012-08-01

    The purpose of this study was to evaluate microbial populations, Hunter's color values (L*, a*, b*) and the sensory quality of freeze-dried miyeokguk, Korean seaweed soup, in order to use it as space food. Microorganisms were not detected in non-irradiated freeze-dried miyeokguk within the detection limit of 1.00 log CFU/g. However, the microbial population in rehydrated miyeokguk was 7.01 log CFU/g after incubation at 35 °C for 48 h, indicating that freeze-dried miyeokguk was not sterilized by heat treatment during the preparation process. Bacteria in the freeze-dried miyeokguk were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei, and Ancinetobacter genomosp. using the 16S rDNA sequencing. In samples that were gamma-irradiated above 10 kGy, it was confirmed that all microorganisms were inactivated. Hunter's color values of the samples irradiated at doses less than 10 kGy were not significantly altered from their baseline appearance (p>0.05). Sensory evaluation showed that preference scores in all sensory properties decreased when freeze-dried miyeokguk was irradiated at doses greater than 10 kGy. Therefore, the results of this study suggest that gamma irradiation at 10 kGy is sufficient to sterilize freeze-dried miyeokguk without significant deterioration in the sensory quality, and thus, the freeze-dried and irradiated miyeokguk at 10 kGy fulfills the microbiological requirements as space food.

  6. A freeze-stable formulation for DTwP and DTaP vaccines.

    Science.gov (United States)

    Xue, Honggang; Yang, Bangling; Kristensen, Debra D; Chen, Dexiang

    2014-01-01

    Inadvertent vaccine freezing often occurs in the cold chain and may cause damage to freeze‑sensitive vaccines. Liquid vaccines that contain aluminum salt adjuvants are particularly vulnerable. Polyol cryoprotective excipients have been shown to prevent freeze damage to hepatitis B vaccine. In this study, we examined the freeze-protective effect of propylene glycol on diphtheria-tetanus-pertussis-whole-cell (DTwP) and acellular (DTaP) vaccines. Pilot lots of DTwP and DTaP formulated with 7.5% propylene glycol underwent 3 freeze-thaw treatments. The addition of propylene glycol had no impact on pH, particle size distribution, or potency of the vaccines prior to freeze-thaw treatment; the only change noted was an increase in osmolality. The potencies and the physical properties of the vaccines containing cryoprotectant were maintained after freeze-thawing and for 3 months in accelerated stability studies. The results from this study indicate that formulating vaccines with propylene glycol can protect diphtheria-tetanus-pertussis vaccines against freeze damages.

  7. Effec t of Freeze-Thaw Cycles on Lipid Oxidation and Myowater in Broiler Chickens

    Directory of Open Access Journals (Sweden)

    S Ali

    2016-03-01

    Full Text Available ABSTRACT The present study was carried out to investigate the influence of freezing-thawing cycles (0, 2, 4 and 6 on lipid oxidation and myowater contents and distribution. Nine replicates of chicken breast meat samples were used for each cycle. Lipid oxidation was determined by measuring peroxide value, and malondialdehyde (MDA concentrations, which reflect thiobarbituric acid reactive substance (TBARS. Color was determined with a digital colorimeter. Muscle moisture contents were determined by drip loss and thawing loss, water holding capacity, and nuclear magnetic resonance (NMR. The results showed that, as the number of freeze-thaw cycles increased, meat redness decreased and MDA and peroxide values increased. Drip loss and thawing loss tended to decreasing as the number of freeze-thaw cycles increased. Water holding capacity also decreased as a function of increasing freeze-thaw cycles. NMR relaxometry profile showed freeze-thaw cycles change the water distribution of meat subjected to multiple freeze-thaw cycles. In conclusion, multiple freezing and thawing rate (6 cycles increased lipid oxidation, decreased myowater, and impaired the color of chicken meat.

  8. Key composition optimization of meat processed protein source by vacuum freeze-drying technology.

    Science.gov (United States)

    Ma, Yan; Wu, Xingzhuang; Zhang, Qi; Giovanni, Vigna; Meng, Xianjun

    2018-05-01

    Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined.

  9. The Effect of Freezing Temperatures on Microdochium majus and M. nivale Seedling Blight of Winter Wheat

    Directory of Open Access Journals (Sweden)

    Ian M. Haigh

    2012-01-01

    Full Text Available Exposure to pre-emergent freezing temperatures significantly delayed the rate of seedling emergence (P<0.05 from an infected and a non-infected winter wheat cv. Equinox seed lot, but significant effects for timing of freezing and duration of freezing on final emergence were only seen for the Microdochium-infested seed lot. Freezing temperatures of −5∘C at post-emergence caused most disease on emerged seedlings. Duration of freezing (12 hours or 24 hours had little effect on disease index but exposure to pre-emergent freezing for 24 hours significantly delayed rate of seedling emergence and reduced final emergence from the infected seed lot. In plate experiments, the calculated base temperature for growth of M. nivale and M. majus was −6.3∘C and −2.2∘C, respectively. These are the first set of experiments to demonstrate the effects of pre-emergent and post-emergent freezing on the severity of Microdochium seedling blight.

  10. Chromosomal integrity of freeze-dried mouse spermatozoa after 137Cs γ-ray irradiation

    International Nuclear Information System (INIS)

    Kusakabe, Hirokazu; Kamiguchi, Yujiroh

    2004-01-01

    This study demonstrated that freeze-dried mouse spermatozoa possess strong resistance to 137 Cs γ-ray irradiation at doses of up to 8 Gy. Freeze-dried mouse spermatozoa were rehydrated and injected into mouse oocytes with an intracytoplasmic sperm injection (ICSI) technique. Most oocytes can be activated after ICSI by using spermatozoa irradiated with γ-rays before and after freeze-drying. Sperm chromosome complements were analyzed at the first cleavage metaphase. Chromosome aberrations increased in a dose-dependent manner in the spermatozoa irradiated before freeze-drying. However, no increase in oocytes with chromosome aberrations was observed when fertilized by spermatozoa that had been irradiated after freeze-drying, as compared with freeze-dried spermatozoa that had not been irradiated. These results suggest that both the chromosomal integrity of freeze-dried spermatozoa, as well as their ability to activate oocytes, were protected from γ-ray irradiation at doses at which chromosomal damage is found to be strongly induced in spermatozoa suspended in solution

  11. Controlled cooling versus rapid freezing of teratozoospermic semen samples: Impact on sperm chromatin integrity

    Directory of Open Access Journals (Sweden)

    Shivananda N Kalludi

    2011-01-01

    Full Text Available Aim: The present study evaluates the impact of controlled slow cooling and rapid freezing techniques on the sperm chromatin integrity in teratozoospermic and normozoospermic samples. Setting: The study was done in a university infertility clinic, which is a tertiary healthcare center serving the general population. Design: It was a prospective study designed in vitro. Materials and Methods: Semen samples from normozoospermic (N=16 and teratozoospermic (N=13 infertile men were cryopreserved using controlled cooling and rapid freezing techniques. The sperm chromatin integrity was analyzed in fresh and frozen-thawed samples. Statistical Analysis Used: Data were reported as mean and standard error (mean ± SEM of mean. The difference between two techniques was determined by a paired t-test. Results: The freeze-thaw induced chromatin denaturation was significantly (P<0.01 elevated in the post-thaw samples of normozoospermic and teratozoospermic groups. Compared to rapid freezing, there was no difference in the number of red sperms (with DNA damage by the controlled slow cooling method in both normozoospermic and teratozoospermic groups. Freeze-thaw induced sperm chromatin denaturation in teratozoospermic samples did not vary between controlled slow cooling and rapid freezing techniques. Conclusions: Since the controlled slow cooling technique involves the use of expensive instrument and is a time consuming protocol, rapid freezing can be a good alternative technique for teratozoospermic and normozoospermic samples when sperm DNA damage is a concern.

  12. Simulation of the process kinetics and analysis of physicochemical properties in the freeze drying of kale

    Science.gov (United States)

    Dziki, Dariusz; Polak, Renata; Rudy, Stanisław; Krzykowski, Andrzej; Gawlik-Dziki, Urszula; Różyło, Renata; Miś, Antoni; Combrzyński, Maciej

    2018-01-01

    Investigations were performed to study the freeze-drying process of kale (Brassica oleracea L. var acephala). The process of freeze-drying was performed at temperatures of 20, 40, and 60°C for whole pieces of leaves and for pulped leaves. The kinetics of the freeze-drying of both kale leaves and kale pulp were best described by the Page model. The increasing freeze-drying temperature from 20 to 60°C induced an approximately two-fold decrease in the drying time. Freeze-drying significantly increased the value of the lightness, delta Chroma, and browning index of kale, and had little influence on the hue angle. The highest increase in the lightness and delta Chroma was observed for whole leaves freeze-dried at 20°C. An increase in the drying temperature brought about a slight decrease in the lightness, delta Chroma and the total colour difference. Pulping decreased the lightness and hue angle, and increased browning index. Freeze-drying engendered a slight decrease in the total phenolics content and antioxidant activity, in comparison to fresh leaves. The temperature of the process and pulping had little influence on the total phenolics content and antioxidant activity of dried kale, but significantly decreased the contents of chlorophyll a and chlorophyll b.

  13. Zone Freezing Study for Pyrochemical Process Waste Minimization

    Energy Technology Data Exchange (ETDEWEB)

    Ammon Williams

    2012-05-01

    Pyroprocessing technology is a non-aqueous separation process for treatment of used nuclear fuel. At the heart of pyroprocessing lies the electrorefiner, which electrochemically dissolves uranium from the used fuel at the anode and deposits it onto a cathode. During this operation, sodium, transuranics, and fission product chlorides accumulate in the electrolyte salt (LiCl-KCl). These contaminates change the characteristics of the salt overtime and as a result, large volumes of contaminated salt are being removed, reprocessed and stored as radioactive waste. To reduce the storage volumes and improve recycling process for cost minimization, a salt purification method called zone freezing has been proposed at Korea Atomic Energy Research Institute (KAERI). Zone freezing is melt crystallization process similar to the vertical Bridgeman method. In this process, the eutectic salt is slowly cooled axially from top to bottom. As solidification occurs, the fission products are rejected from the solid interface and forced into the liquid phase. The resulting product is a grown crystal with the bulk of the fission products near the bottom of the salt ingot, where they can be easily be sectioned and removed. Despite successful feasibility report from KAERI on this process, there were many unexplored parameters to help understanding and improving its operational routines. Thus, this becomes the main motivation of this proposed study. The majority of this work has been focused on the CsCl-LiCl-KCl ternary salt. CeCl3-LiCl-KCl was also investigated to check whether or not this process is feasible for the trivalent species—surrogate for rare-earths and transuranics. For the main part of the work, several parameters were varied, they are: (1) the retort advancement rate—1.8, 3.2, and 5.0 mm/hr, (2) the crucible lid configurations—lid versus no-lid, (3) the amount or size of mixture—50 and 400 g, (4) the composition of CsCl in the salt—1, 3, and 5 wt%, and (5) the

  14. Substituting freshwater: Can ocean desalination and water recycling capacities substitute for groundwater depletion in California?

    Science.gov (United States)

    Badiuzzaman, Pierre; McLaughlin, Eoin; McCauley, Darren

    2017-12-01

    While the sustainability of resource depletion is a longstanding environmental concern, wider attention has recently been given to growing water scarcity and groundwater depletion. This study seeks to test the substitutability assumption embedded in weak sustainability indicators using a case study of Californian water supply. The volume of groundwater depletion is used as a proxy for unsustainable water consumption, and defined by synthesising existing research estimates into low, medium and high depletion baselines. These are compared against projected water supply increases from ocean desalination and water recycling by 2035, to determine whether new, drought-proof water sources can substitute for currently unsustainable groundwater consumption. Results show that the maximum projected supply of new water, 2.47 million acre-feet per year (MAF/yr), is sufficient to meet low depletion estimates of 2.02 MAF/yr, but fails to come near the high depletion estimate of 3.44 MAF/yr. This does not necessarily indicate physical limitations of substitutability, but more so socio-economic limitations influenced by high comparative costs. By including capacities in demand-substitutability via urban water conservation, maximum predicted capacities reach 5.57 MAF/yr, indicating wide room for substitution. Based on these results, investment in social and institutional capital is an important factor to enhance demand-side substitutability of water and other natural resources, which has been somewhat neglected by the literature on the substitutability of natural resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems

    Energy Technology Data Exchange (ETDEWEB)

    Hafsteinsdottir, Erla G., E-mail: erla.hafsteinsdottir@gmail.com [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); White, Duanne A., E-mail: duanne.white@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Gore, Damian B., E-mail: damian.gore@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Stark, Scott C., E-mail: scott.stark@aad.gov.au [Environmental Protection and Change, Australian Antarctic Division, Department of Sustainability, Environment, Water, Population and Communities, Tasmania 7050 (Australia)

    2011-12-15

    Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H{sub 2}PO{sub 4}){sub 2}] or sodium phosphate [Na{sub 3}PO{sub 4}]) reacts with lead (PbSO{sub 4} or PbCl{sub 2}) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 deg. C to -20 deg. C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO{sub 4} and Na{sub 3}PO{sub 4} were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate. - Highlights: > Formation of lead phosphate products in cold environments is identified. > Potential change in formation during freeze-thaw cycling is assessed. > Lead phosphate reaction efficiency varies according to phosphate and lead source. > Pyromorphite formation is stable during 240 freeze-thaw cycles. - Pyromorphite, formed from Pb phosphate fixation, is stable during multiple freeze-thaw cycles but the efficiency of the fixation depends on the phosphate source and the type of Pb mineral.

  16. Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems

    International Nuclear Information System (INIS)

    Hafsteinsdottir, Erla G.; White, Duanne A.; Gore, Damian B.; Stark, Scott C.

    2011-01-01

    Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H 2 PO 4 ) 2 ] or sodium phosphate [Na 3 PO 4 ]) reacts with lead (PbSO 4 or PbCl 2 ) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 deg. C to -20 deg. C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO 4 and Na 3 PO 4 were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate. - Highlights: → Formation of lead phosphate products in cold environments is identified. → Potential change in formation during freeze-thaw cycling is assessed. → Lead phosphate reaction efficiency varies according to phosphate and lead source. → Pyromorphite formation is stable during 240 freeze-thaw cycles. - Pyromorphite, formed from Pb phosphate fixation, is stable during multiple freeze-thaw cycles but the efficiency of the fixation depends on the phosphate source and the type of Pb mineral.

  17. Ice nucleation activity in various tissues of Rhododendron flower buds: their relevance to extraorgan freezing

    Directory of Open Access Journals (Sweden)

    Masaya eIshikawa

    2015-03-01

    Full Text Available Wintering flower buds of cold hardy Rhododendron japonicum cooled slowly to subfreezing temperatures are known to undergo extraorgan freezing, whose mechanisms remain obscure. We revisited this material to demonstrate why bud scales freeze first in spite of their lower water content, why florets remain deeply supercooled and how seasonal adaptive responses occur in regard to extraorgan freezing in flower buds. We determined ice nucleation activity (INA of various flower bud tissues of using a test tube-based assay. Irrespective of collection sites, outer and inner bud scales that function as ice sinks in extraorgan freezing had high INA levels whilst florets that remain supercooled and act as a water source lacked INA. The INA level of bud scales was not high in late August when flower bud formation was ending, but increased to reach the highest level in late October just before the first autumnal freeze. The results support the following hypothesis: the high INA in bud scales functions as the subfreezing sensor, ensuring the primary freezing in bud scales at warmer subzero temperatures, which likely allows the migration of floret water to the bud scales and accumulation of icicles within the bud scales. The low INA in the florets helps them remain unfrozen by deep supercooling. The INA in the bud scales was resistant to grinding and autoclaving at 121°C for 15 min, implying the intrinsic nature of the INA rather than of microbial origin, whilst the INA in stem bark was autoclaving labile. Anti-nucleation activity (ANA was implicated in the leachate of autoclaved bud scales, which suppresses the INA at millimolar levels of concentration and likely differs from the colligative effects of the solutes. The tissue INA levels likely contribute to the establishment of freezing behaviors by ensuring the order of freezing in the tissues: from the primary freeze to the last tissue remaining unfrozen.

  18. Freeze-Thaw Cycles and Soil Biogeochemistry: Implications for Greenhouse Gas emission

    Science.gov (United States)

    Rezanezhad, F.; Milojevic, T.; Oh, D. H.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2016-12-01

    Freeze-thaw cycles represent a major natural climate forcing acting on soils at middle and high latitudes. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles regulate carbon and nitrogen cycling and how these transformations influence greenhouse gas (GHG) fluxes. We present a novel approach, which combines the acquisition of physical and chemical data in a newly developed experimental soil column system. This system simulates realistic soil temperature profiles during freeze-thaw cycles. A high-resolution, Multi-Fiber Optode (MuFO) microsensor technique was used to detect oxygen (O2) continuously in the column at multiple depths. Surface and subsurface changes to gas and aqueous phase chemistry were measured to delineate the pathways and quantify soil respiration rates during freeze-thaw cycles. The results indicate that the time-dependent release of GHG from the soil surface is influenced by a combination of two key factors. Firstly, fluctuations in temperature and O2 availability affect soil biogeochemical activity and GHG production. Secondly, the recurrent development of a physical ice barrier prevents exchange of gaseous compounds between the soil and atmosphere during freezing conditions; removal of this barrier during thaw conditions increases GHG fluxes. During freezing, O2 levels in the unsaturated zone decreased due to restricted gas exchange with the atmosphere. As the soil thawed, O2 penetrated deeper into the soil enhancing the aerobic mineralization of organic carbon and nitrogen. Additionally, with the onset of thawing a pulse of gas flux occurred, which is attributed to the build-up of respiratory gases in the pore space during freezing. The latter implies enhanced anaerobic respiration as O2 supply ceases when the upper soil layer freezes.

  19. Cell growth and resistance of Lactococcus lactis subsp. lactis TOMSC161 following freezing, drying and freeze-dried storage are differentially affected by fermentation conditions.

    Science.gov (United States)

    Velly, H; Fonseca, F; Passot, S; Delacroix-Buchet, A; Bouix, M

    2014-09-01

    To investigate the effects of fermentation parameters on the cell growth and on the resistance to each step of the freeze-drying process of Lactococcus lactis subsp. lactis TOMSC161, a natural cheese isolate, using a response surface methodology. Cells were cultivated at different temperatures (22, 30 and 38°C) and pH (5·6, 6·2 and 6·8) and were harvested at different growth phases (0, 3 and 6 h of stationary phase). Cultivability and acidification activity losses of Lc. lactis were quantified after freezing, drying, 1 and 3 months of storage at 4 and 25°C. Lactococcus lactis was not damaged by freezing but was sensitive to drying and to ambient temperature storage. Moreover, the fermentation temperature and the harvesting time influenced the drying resistance of Lc. lactis. Lactococcus lactis cells grown in a whey-based medium at 32°C, pH 6·2 and harvested at late stationary phase exhibited both an optimal growth and the highest resistance to freeze-drying and storage. A better insight on the individual and interaction effects of fermentation parameters made it possible the freeze-drying and storage preservation of a sensitive strain of technological interest. Evidence on the particularly damaging effect of the drying step and the high-temperature storage is presented. © 2014 The Society for Applied Microbiology.

  20. Mechanisms of deterioration of nutrients. [freeze drying methods for space flight food

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1974-01-01

    Methods are reported by which freeze dried foods of improved quality will be produced. The applicability of theories of flavor retention has been demonstrated for a number of food polymers, both proteins and polysacchardies. Studies on the formation of structures during freeze drying have been continued for emulsified systems. Deterioration of organoleptic quality of freeze dried foods due to high temperature heating has been evaluated and improved procedures developed. The influence of water activity and high temperature on retention of model flavor materials and browning deterioration has been evaluated for model systems and food materials.

  1. An Equipment to Measure the Freezing Point of Soils under Higher Pressure

    Science.gov (United States)

    Wang, Dayan; Guan, Hui; Wen, Zhi; Ma, Wei

    2014-05-01

    Soil freezing point is the highest temperature at which ice can be presented in the system and soil can be referred to as frozen. The freezing temperature of soil is an important parameter for solving many practical problems in civil engineering, such as evaluation of soil freezing depth, prediction of soil heaving, force of soil suction, etc. However, as the freezing temperature is always affected by many factors like soil particle size, mineral composition, water content and the external pressure endured by soils, to measure soil freezing point is a rather difficult task until now, not to mention the soil suffering higher pressure. But recently, with the artificial freezing technology widely used in the excavation of deep underground space, the frozen wall thickness is a key factor to impact the security and stability of deep frozen wall. To determine the freeze wall thickness, the location of the freezing front must be determined firstly, which will deal with the determination of the soil freezing temperature. So how to measure the freezing temperature of soil suffering higher pressure is an important problem to be solved. This paper will introduce an equipment which was developed lately by State Key Laboratory of Frozen Soil Engineering to measure the freezing-point of soils under higher pressure. The equipment is consisted of cooling and keeping temperature system, temperature sensor and data collection system. By cooling and keeping temperature system, not only can we make the higher pressure soil sample's temperature drop to a discretionary minus temperature, but also keep it and reduce the heat exchange of soil sample with the outside. The temperature sensor is the key part to our measurement, which is featured by high precision and high sensitivity, what is more important is that the temperature sensor can work in a higher pressure condition. Moreover, the major benefit of this equipment is that the soil specimen's loads can be loaded by any microcomputer

  2. Design and evaluation of aircraft heat source systems for use with high-freezing point fuels

    Science.gov (United States)

    Pasion, A. J.

    1979-01-01

    The objectives were the design, performance and economic analyses of practical aircraft fuel heating systems that would permit the use of high freezing-point fuels on long-range aircraft. Two hypothetical hydrocarbon fuels with freezing points of -29 C and -18 C were used to represent the variation from current day jet fuels. A Boeing 747-200 with JT9D-7/7A engines was used as the baseline aircraft. A 9300 Km mission was used as the mission length from which the heat requirements to maintain the fuel above its freezing point was based.

  3. Exploring high-density baryonic matter: Maximum freeze-out density

    Energy Technology Data Exchange (ETDEWEB)

    Randrup, Joergen [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Cleymans, Jean [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Rondebosch (South Africa)

    2016-08-15

    The hadronic freeze-out line is calculated in terms of the net baryon density and the energy density instead of the usual T and μ{sub B}. This analysis makes it apparent that the freeze-out density exhibits a maximum as the collision energy is varied. This maximum freeze-out density has μ{sub B} = 400 - 500 MeV, which is above the critical value, and it is reached for a fixed-target bombarding energy of 20-30 GeV/N well within the parameters of the proposed NICA collider facility. (orig.)

  4. Deep freezing of cattle embryos in glass ampules or French straws.

    Science.gov (United States)

    Massip, A; Van der Zwalmen, P; Ectors, F; De Coster, R; D'Ieteren, G; Hanzen, C

    1979-08-01

    Ninety four cow embryos recovered on day 7-8 after onset of oestrus were frozen by the "Two Step" freezing procedure: 49 in pyrex glass ampules and 45 in .25 ml French semen straws. The overall survival rate was 33.7% (36.2% for embryos frozen in glass ampules; 31.1% for embryos frozen in plastic straws). 45.2% of transferred embryos resulted in pregnancies (35.7% after freezing in glass ampules v.s 52.9% after freezing in plastic straws).

  5. Visualization data on the freezing process of micrometer-scaled aqueous citric acid drops

    Directory of Open Access Journals (Sweden)

    Anatoli Bogdan

    2017-02-01

    Full Text Available The visualization data (8 movies presented in this article are related to the research article entitled “Freezing and glass transitions upon cooling and warming and ice/freeze-concentration-solution morphology of emulsified aqueous citric acid” (A. Bogdan, M.J. Molina, H. Tenhu, 2016 [1]. The movies recorded in-situ with optical cryo-miscroscopy (OC-M demonstrate for the first time freezing processes that occur during the cooling and subsequent warming of emulsified micrometer-scaled aqueous citric acid (CA drops. The movies are made publicly available to enable critical or extended analyzes.

  6. Transient debris freezing and potential wall melting during a severe reactivity initiated accident experiment

    International Nuclear Information System (INIS)

    El-Genk, M.S.; Moore, R.L.

    1981-01-01

    It is important to light water reactor (LWR) safety analysis to understand the transient freezing of molten core debris on cold structures following a hypothetical core meltdown accident. The purpose of this paper is to (a) present the results of a severe reactivity initiated accident (RIA) in-pile experiment with regard to molten debris distribution and freezing following test fuel rod failure, (b) analyze the transient freezing of molten debris (primarily a mixture of UO/sub 2/ fuel and Zircaloy cladding) deposited on the inner surface of the test shroud wall upon rod failure, and (c) assess the potential for wall melting upon being contacted by the molten debris. 26 refs

  7. P. Electricity demand, substitution and resources

    International Nuclear Information System (INIS)

    1976-01-01

    This report discusses the demand for electricity in New Zealand, the accuracy of demand predictions, and whether some other form of energy could be substituted for electricity. It then discusses past and possible future electricity generation in New Zealand by geothermal steam and hydro power and the resources of gas and coal that could be made available for electricity generation

  8. Endogenous cueing attenuates object substitution masking.

    Science.gov (United States)

    Germeys, Filip; Pomianowska, I; De Graef, P; Zaenen, P; Verfaillie, K

    2010-07-01

    Object substitution masking (OSM) is a form of visual masking in which a briefly presented target surrounded by four small dots is masked by the continuing presence of the four dots after target offset. A major parameter in the prediction of OSM is the time required for attention to be directed to the target following its onset. Object substitution theory (Di Lollo et al. in J Exp Psychol Gen 129:481-507, 2000) predicts that the sooner attention can be focused at the target's location, the less masking will ensue. However, recently Luiga and Bachmann (Psychol Res 71:634-640, 2007) presented evidence that precueing of attention to the target location prior to target-plus-mask onset by means of a central (endogenous) arrow cue does not reduce OSM. When attention was cued exogenously, OSM was attenuated. Based on these results, Luiga and Bachmann argued that object substitution theory should be adapted by differentiating the ways of directing attention to the target location. The goal of the present study was to further examine the dissociation between the effects of endogenous and exogenous precueing on OSM. Contrary to Luiga and Bachmann, our results show that prior shifts of attention to the target location initiated by both exogenous and endogenous cues reduce OSM as predicted by object substitution theory and its computational model CMOS.

  9. Substitute fluid examinations for liquid manure

    Directory of Open Access Journals (Sweden)

    Schrader Kevin

    2017-01-01

    Full Text Available For the farming industry it is essential to use liquid manure as natural fertilizer. Through new agricultural regulation 2015 in Germany the industry must develop new liquid manure spreader systems because the ammonia and methane emission are limited. In a research project the University of Applied Sciences Zwickau and some other industry partners will develop such a new innovative liquid manure spreader. The new liquid manure spreader should use pulsating air to distribute the liquid manure exactly. The pulsating air, which flows through the pipelines, should be analysed at a test station. For examinations at this test station it is important to find another substitute fluid because liquid manure smells strong, is not transparent and is also not homogeneous enough for scientific investigations. Furthermore it is important to ensure that the substitute fluid is, like liquid manure, a non-Newtonian fluid. The substitute fluid must be a shear-thinning substance - this means the viscosity decrease at higher shear rate. Many different samples like soap-water-farragoes, jelly-water-farragoes, agar-water-farragoes, soap-ethanol-farragoes and more are, for the project, examined in regard of their physical properties to find the best substitute fluid. The samples are examined at the rotational viscometer for viscosity at various shear rates and then compared with the viscosity values of liquid manure.

  10. Substitute fluid examinations for liquid manure

    Science.gov (United States)

    Schrader, Kevin; Riedel, Marco; Eichert, Helmut

    For the farming industry it is essential to use liquid manure as natural fertilizer. Through new agricultural regulation 2015 in Germany the industry must develop new liquid manure spreader systems because the ammonia and methane emission are limited. In a research project the University of Applied Sciences Zwickau and some other industry partners will develop such a new innovative liquid manure spreader. The new liquid manure spreader should use pulsating air to distribute the liquid manure exactly. The pulsating air, which flows through the pipelines, should be analysed at a test station. For examinations at this test station it is important to find another substitute fluid because liquid manure smells strong, is not transparent and is also not homogeneous enough for scientific investigations. Furthermore it is important to ensure that the substitute fluid is, like liquid manure, a non-Newtonian fluid. The substitute fluid must be a shear-thinning substance - this means the viscosity decrease at higher shear rate. Many different samples like soap-water-farragoes, jelly-water-farragoes, agar-water-farragoes, soap-ethanol-farragoes and more are, for the project, examined in regard of their physical properties to find the best substitute fluid. The samples are examined at the rotational viscometer for viscosity at various shear rates and then compared with the viscosity values of liquid manure.

  11. Trace maps for arbitrary substitution sequences

    International Nuclear Information System (INIS)

    Avishai, Y.

    1993-01-01

    The discovery of quasi-crystals and their 1-dimensional modeling have led to a deep mathematical study of Schroedinger operators with an arbitrary deterministic potential sequence. In this work we address this problem and find trace maps for an arbitrary substitution sequence. our trace maps have lower dimensionality than those of Kolar and Nori, which make them quite attractive for actual applications. (authors)

  12. Fossil Fuels, Backstop Technologies, and Imperfect Substitution

    NARCIS (Netherlands)

    van der Meijden, G.C.; Pittel, Karen; van der Ploeg, Frederick; Withagen, Cees

    2014-01-01

    This chapter studies the transition from fossil fuels to backstop technologies in a general equilibrium model in which growth is driven by research and development. The analysis generalizes the existing literature by allowing for imperfect substitution between fossil fuels and the new energy

  13. 3-Substituted 2-phenyl-indoles

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Jørgensen, T.B.; Gloriam, D.E.

    2013-01-01

    -indoles with a variety of substituents at the indole 3-position. Herein we describe the development of optimised and efficient synthetic routes to a series of new 2-phenyl-indole building blocks 3 to 9 and show that these can be used to generate a broad variety of 3-substituted 2-phenyl-indoles of interest to medicinal...

  14. Law of substitution for mixed arrays

    International Nuclear Information System (INIS)

    Koudelka, A.J.

    1987-01-01

    The nuclear safety justification of a mixed array of dissimilar fissile units of metal units and dilute solution units, according to Clayton, has been a persistent and nagging problem. Dissimilar uranium metal or dissimilar uranium solution units in a mixed array can also create a modeling nightmare for the nuclear criticality safety engineer. Now, a calculational method known as the Law of Substitution has been developed to ensure that the k/sub eff/ of an array of uranium metal and uranium solution units will satisfy any k/sub eff/ limit set by the nuclear safety engineer. The nuclear criticality safety engineer can utilize the Law of Substitution to safely mix or substitute different uranium metal units, different uranium solution units, and more importantly, uranium metal and dilute UO 2 solution units in an array. The Law of Substitution is as follows: (1) calculate the k/sub eff/ of each unit type in its own infinite planar array. (2) Determine the edge-to-edge spacing of the infinite planar array of each type of unit to satisfy a desired k/sub eff/. (3) Select the largest edge-to-edge spacing from among the similar units in their infinite planar arrays and use that spacing for the finite or infinite planar array of mixed units

  15. Thermal stability of 4-substituted benzenediazonium tetrafluoroborates

    International Nuclear Information System (INIS)

    Bruner, V.Ya.

    1990-01-01

    Heating of tetraborates of 4-methyl-, 4-phenyl- and 4-dimethylaminobenzenediazonium at 95, 120 and 148 deg, correspondingly, causes their autocatalytic destruction, two moles of gas (nitrogen, boron fluoride) being liberated. The thermal stability of 4-substituted benzenediazonium tetrafluoroborates increases with the increase of the electron-donor activity of the substituent at benzene ring

  16. complexes based on meso-substituted dipyrrins

    Indian Academy of Sciences (India)

    Keywords. Coordination polymers; meso-substituted dipyrrins; heteroleptic; acetylacetonato; ... Room temperature magnetic susceptibility measurements were ... After cooling to ambient tem- perature it ... crystals of 1 were obtained from CH2Cl2/ hexane (1. : 1) solution. .... are air-stable, crystalline solids, soluble in common.

  17. Facile Synthesis of N -Substituted Benzimidazoles

    NARCIS (Netherlands)

    Kurhade, Santosh; Rossetti, Arianna; Dömling, Alexander

    2016-01-01

    A particularly mild and efficient one-pot synthesis of N-substituted benzimidazole derivatives was developed. 2-Fluoro-5-nitrophenylisocyanide reacts with a diverse set of primary amines to afford the respective products in moderate to very good yield (35-95%; 20 examples).

  18. Symptomatic hemorrhagic complications associated with dural substitutes

    Directory of Open Access Journals (Sweden)

    Po-Yuan Chen

    2018-01-01

    Conclusion: The increased risk of hemorrhagic complications associated with craniotomy is modified by choice of dural replacement. Our results could assist clinicians in their decision-making with respect to the optimal timing for synthetic dural substitutes in patients with tumor infiltration of the patient's dura, severe brain swelling in traumatic brain injury, or a result of shrinkage from exposure and electrocautery.

  19. Stochastic diffusion models for substitutable technological innovations

    NARCIS (Netherlands)

    Wang, L.; Hu, B.; Yu, X.

    2004-01-01

    Based on the analysis of firms' stochastic adoption behaviour, this paper first points out the necessity to build more practical stochastic models. And then, stochastic evolutionary models are built for substitutable innovation diffusion system. Finally, through the computer simulation of the

  20. Ultrasound Promoted Synthesis of Bis(substituted pyrazol-4-ylcarbonyl-Substituted Thioureas

    Directory of Open Access Journals (Sweden)

    Li Xiao

    2009-03-01

    Full Text Available A series of novel bis(substituted pyrazol-4-ylcarbonyl-substituted thioureas have been synthesized by the reactions of substituted pyrazol-4-ylcarbonyl isothiocyanates with different diamines under ultrasound irradiation and classical heating method at 20-25 °C. In general, substantial improvement in rates and modest yields increases were observed when reactions were carried out under sonication, compared with the classical heating method. The structures of these compounds have been elucidated by elemental and spectral (IR, 1H-NMR analysis.

  1. Postural control and freezing of gait in Parkinson's disease.

    Science.gov (United States)

    Schlenstedt, Christian; Muthuraman, Muthuraman; Witt, Karsten; Weisser, Burkhard; Fasano, Alfonso; Deuschl, Günther

    2016-03-01

    The relationship between freezing of gait (FOG) and postural instability in Parkinson's disease (PD) is unclear. We analyzed the impact of FOG on postural control. 31 PD patients with FOG (PD+FOG), 27 PD patients without FOG (PD-FOG) and 22 healthy control (HC) were assessed in the ON state. Postural control was measured with the Fullerton Advanced Balance (FAB) scale and with center of pressure (COP) analysis during quiet stance and maximal voluntary forward/backward leaning. The groups were balanced concerning age, disease duration and disease severity. PD+FOG performed significantly worse in the FAB scale (21.8 ± 5.8) compared to PD-FOG (25.6 ± 5.0) and HC (34.9 ± 2.4) (mean ± SD, p postural control asymmetry. PD+FOG have reduced postural control compared to PD-FOG and HC. Our results show a relationship between the anterior-posterior COP position during quiet stance and FOG. The COP shift towards posterior in PD+FOG leads to a restricted precondition to generate forward progression during gait initiation. This may contribute to the occurrence of FOG or might be a compensatory strategy to avoid forward falls. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Failure of cement hydrates: freeze-thaw and fracture

    Science.gov (United States)

    Ioannidou, Katerina; Del Gado, Emanuela; Ulm, Franz-Josef; Pellenq, Roland

    Mechanical and viscoelastic behavior of concrete crucially depends on cement hydrates, the ``glue'' of cement. Even more than the atomistic structure, the mesoscale amorphous texture of cement hydrates over hundreds of nanometers plays a crucial role for material properties. We use simulations that combine information of the nano-scale building units of cement hydrates and on their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles.Our mesoscale model was able to reconcile different experimental results ranging from small-angle neutron scattering, SEM, adsorption/desorption of N2, and water to nanoindentation and gain the new fundamental insights into the microscopic origin of the properties measured. Our results suggest that heterogeneities developed during the early stages of hydration persist in the structure of C-S-H, impacting the rheological and mechanical performance of the hardened cement paste. In this talk I discuss recent investigation on failure mechanism at the mesoscale of hardened cement paste such as freeze-thaw and fracture. Using correlations between local volume fractions and local stress we provide a link between structural and mechanical heterogeneities during the failure mechanisms.

  3. Analytic-numerical method of determining the freezing front location

    Directory of Open Access Journals (Sweden)

    R. Grzymkowski

    2011-07-01

    Full Text Available Mathematical modeling of thermal processes combined with the reversible phase transitions of type: solid phase – liquid phase leads to formulation of the parabolic boundary problems with the moving boundary. Solution of such defined problem requires, most often, to use sophisticated numerical techniques and far advanced mathematical tools. Excellent illustration of the complexity of considered problems, as well as of the variety of approaches used for finding their solutions, gives the papers [1-4]. In the current paper, the authors present the, especially attractive from the engineer point of view, analytic-numerical method for finding the approximate solution of selected class of problems which can be reduced to the one-phase solidification problem of a plate with the unknown a priori, varying in time boundary of the region in which the solution is sought. Proposed method is based on the known formalism of initial expansion of the sought function describing the temperature field into the power series, some coefficients of which are determined with the aid of boundary conditions, and on the approximation of the function defining the location of freezing front with the broken line, parameters of which are numerically determined.

  4. INFLUENCE OF LONG LASTING FREEZING TO BAKING QUALITY

    Directory of Open Access Journals (Sweden)

    Jana Šmitalová

    2013-12-01

    Full Text Available Foodstuff adapted by freezing is able to use for final setting immediately and its important contribution is sparing of working action and time connected to their next setting in our households or in catering corporations. In frame of this topic some baking experiment were realized with application of the main component – smooth wheat flour T 650 and the raw yeasting. It was monitored the baking quality of loafs made of fresh dough and loafs made of dough which was frozen one, two, three, four, five, six and nine months in -18°C. The biggest decline of the quality of bread made from frozen dough was monitored right after the first month. Decline of its size was 19.0%. Strong decline of size was monitored after five months (18.1% and after six months of storage in freezer (23.8%. Decline of baking quality during storage was mainly caused by declining activity of yeasts and by the loss of their yeasty ability. These conditions cased gradual decline of the solidity of the dough.

  5. Mouse-resistant insulated covers keep pipes from freezing

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-01-15

    Fabric wellhead covers and insulated blankets are commonly used at well sites in the Wyoming coalbed methane field to keep surface pipes from freezing. These materials are often chewed up by mice who build nests close to the warm pipes. The mice attract rattlesnakes, a potentially serious problem for the workmen who check the wells daily. Kennon Products of Sheridan, Wyoming solved this problem by making a flexible covering material that has a coating of hardened guard plates that prevents mice from chewing through it. More than a hundred of Kennon's mouse-resistant wellhead covers have been used successfully in the gas fields for over a year. They can be installed in less than 30 minutes and cost only a fraction of what a fiberglass hut costs to purchase and install. Huts are being discouraged for use on federal lands because they alter the nesting patterns of eagles, who perch upon them to hunt rodents. Huts also trap methane gas, which is a potential safety hazard. Kennon's mouse-resistant wellhead covers are lower than the fiberglass huts and blend into the landscape. The company is working on camouflage colours to make wellheads less noticeable. In the future, the company plans to insulate water pipes. 1 fig.

  6. Anisotropic silk fibroin/gelatin scaffolds from unidirectional freezing

    Energy Technology Data Exchange (ETDEWEB)

    Asuncion, Maria Christine Tankeh, E-mail: christine.asuncion@u.nus.edu [National University of Singapore, Department of Biomedical Engineering (Singapore); Goh, James Cho-Hong [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Orthopedic Surgery (Singapore); Toh, Siew-Lok [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Mechanical Engineering (Singapore)

    2016-10-01

    Recent studies have underlined the importance of matching scaffold properties to the biological milieu. Tissue, and thus scaffold, anisotropy is one such property that is important yet sometimes overlooked. Methods that have been used to achieve anisotropic scaffolds present challenges such as complicated fabrication steps, harsh processing conditions and toxic chemicals involved. In this study, unidirectional freezing was employed to fabricate anisotropic silk fibroin/gelatin scaffolds in a simple and mild manner. Morphological, mechanical, chemical and cellular compatibility properties were investigated, as well as the effect of the addition of gelatin to certain properties of the scaffold. It was shown that scaffold properties were suitable for cell proliferation and that mesenchymal stem cells were able to align themselves along the directed fibers. The fabricated scaffolds present a platform that can be used for anisotropic tissue engineering applications such as cardiac patches. - Highlights: • Silk/gelatin scaffolds with unidirectional alignment were fabricated using a simple and scalable process • Presence of gelatin in silk resulted to lesser shrinkage, better water retention and improved cell proliferation. • Mesenchymal stem cells were shown to align themselves according to the fiber alignment.

  7. Kyanite from the Deep Freeze Range, Terra Nova Bay, Antarctica

    International Nuclear Information System (INIS)

    Skinner, D.N.B.; Estrada, S.

    2002-01-01

    During GANOVEX VII in 1992, kyanite was discovered in quartz veins on the southwest flank of Mt Levick, in the Deep Freeze Range, Terra Nova Bay, Antarctica. The quartz veins cut an isoclinally (D 1 ) folded sequence of low-grade (Mu-Bt-Crd±And±St) pelitic schist with associated para-amphibolites, calc-silicates, and quartzites (Priestley Formation), which forms the western, steeply dipping to overturned limb of a D 2 , kilometric fold. The schists grade northeastwards into higher grade schists (Kfs-Sil-Crd) of the low-angle upper limb of the D 2 fold, and thus the regional metamorphism postdates the fold. D 3 southeast-verging folds lie on the upper limb. The kyanite crystals (up to 3.5 cm long) occur with paragonitic muscovite and minor plagioclase (An 36 . The quartz veins and saddle reefs are cleaved and boudinaged, but the kyanite shows only mild deformation suggesting late tectonic growth. There is no indication that the host schists entered the stability field of kyanite. The change in P-T conditions that promoted the growth of kyanite appears to have been transient and temporally insufficient to allow the country rocks to react. It is suggested that the action of the nearby Boomerang Thrust bringing older gneiss over the Priestley Formation schists could have generated the D 3 folds and provided the necessary overpressure conditions for the kyanite to grow from the quartz vein fluids. (author). 23 refs., 5 figs., 1 tab

  8. Colder freeze-in axinos decaying into photons

    Science.gov (United States)

    Bae, Kyu Jung; Kamada, Ayuki; Liew, Seng Pei; Yanagi, Keisuke

    2018-03-01

    We point out that 7 keV axino dark matter (DM) in the R-parity violating (RPV) supersymmetric (SUSY) Dine-Fischler-Srednicki-Zhitnitsky axion model can simultaneously reproduce the 3.5 keV x-ray line excess and evade stringent constraints from the Ly -α forest data. Peccei-Quinn symmetry breaking naturally generates both the TeV-scale μ term and the MeV-scale RPV term. The RPV term introduces a tiny axino-neutrino mixing and provides axino DM as a variant of the sterile neutrino DM explaining the 3.5 keV x-ray line excess. Axinos are produced by freeze-in processes via the μ term. The resultant phase space distribution tends to be colder than the Fermi-Dirac distribution. The inherent entropy production from late-time saxion decay makes axinos even colder than those without saxion decay. The resultant axino DM takes the correct relic density and is compatible even with the latest and strongest constraint from the Ly-α forest data.

  9. Freeze and restart of the DWPF Scale Glass Melter

    International Nuclear Information System (INIS)

    Choi, A.S.

    1989-01-01

    After over two years of successful demonstration of many design and operating concepts of the DWPF Melter system, the last Scale Glass Melter campaign was initiated on 6/9/88 and consisted of two parts; (1) simulation of noble metal buildup and (2) freeze and subsequent restart of the melter under various scenarios. The objectives were to simulate a prolonged power loss to major heating elements and to examine the characteristics of transient melter operations during a startup with a limited supply of lid heat. Experimental results indicate that in case of a total power loss to the lower electrodes such as due to noble metal deposition, spinel crystals will begin to form in the SRL 165 composite waste glass pool in 24 hours. The total lid heater power required to initiate joule heating was the same as that during slurry-feeding. Results of a radiative heat transfer analysis in the plenum indicate that under the identical operating conditions, the startup capabilities of the SGM and the DWPF Melter are quite similar, despite a greater lid heater to melt surface area ratio in the DWPF Melter

  10. Early Freezing of Gait: Atypical versus Typical Parkinson Disorders

    Directory of Open Access Journals (Sweden)

    Abraham Lieberman

    2015-01-01

    Full Text Available In 18 months, 850 patients were referred to Muhammad Ali Parkinson Center (MAPC. Among them, 810 patients had typical Parkinson disease (PD and 212 had PD for ≤5 years. Among the 212 patients with early PD, 27 (12.7% had freezing of gait (FOG. Forty of the 850 had atypical parkinsonism. Among these 40 patients, all of whom had symptoms for ≤5 years, 12 (30.0% had FOG. FOG improved with levodopa in 21/27 patients with typical PD but did not improve in the 12 patients with atypical parkinsonism. FOG was associated with falls in both groups of patients. We believe that FOG unresponsive to levodopa in typical PD resembles FOG in atypical parkinsonism. We thus compared the 6 typical PD patients with FOG unresponsive to levodopa plus the 12 patients with atypical parkinsonism with the 21 patients with typical PD responsive to levodopa. We compared them by tests of locomotion and postural stability. Among the patients with FOG unresponsive to levodopa, postural stability was more impaired than locomotion. This finding leads us to believe that, in these patients, postural stability, not locomotion, is the principal problem underlying FOG.

  11. Method of freezing type dismantling for wasted reactors

    International Nuclear Information System (INIS)

    Tatsumi, Toshiyuki.

    1985-01-01

    Purpose: To enable to operate a cutting device in the air by placing a working table on ice while utilizing the ice as radiation shielding materials thereby prevent the diffusion of air contaminations. Method: Upon dismantling a BWR type reactor, ice is packed into a reactor container and a pressure vessel and frozen state is maintained by cooling coils disposed to the outer circumference of the pressure vessel. Then, an airtight hood is covered over the pressure vessel and a working table is rotatably disposed therein. Upon working, when the upper layer ice is melted by a heat pump and discharged, the airtight hood is lowered to a predetermined level. After freezing the melted portion again at the lowered level, cutting work is conducted by an operator in the hood. The cut pieces are conveyed after hoisting the airtight hood by a crane. The pressure vessel is dismantled by repeating the foregoing procedures. In this way, cut pieces can be recovered without falling them to the reactor bottom as in the conventional work in water. In addition, since the procedures are conducted while covering the airtight hood, diffusion of air contaminations can be prevented. (Kamimura, M.)

  12. Investigation of the process of vacuum freeze drying of bacterial concentrates for the meat industry with cryogenic freezing

    Directory of Open Access Journals (Sweden)

    V. V. Poymanov

    2016-01-01

    Full Text Available The research results of the nutritional value of the products manufactured are presented in the article. The main directions of bacterial concentrates application in the meat industry were determined. The analysis of starter cultures was given. The range of products manu-factured with bacterial concentrates was analyzed. It was shown that the introduction of innovative technologies will enable dynamic development of both large and small enterprises, which will create prerequisites for the growth of the Russian market of meat products. Economic efficiency of the studied substances treatment methods was proved. The relevance of the development of technology of pro-duction of dry bacterial concentrates with cryogenic freezing was proved. An integrated approach to the development of competitive domestic technologies and equipment for cryofreezing and sublimation dehydration by the use of granulation for the intensification of the internal heat and mass transfer, reducing specific energy consumption through the use of a combined cold supply system was pro-posed. Results of the study of the kinetics of the freezing process with the traditional method and cryofreezing are given in the paper. Rational parameters of the cryofreezing process were proposed. The optimum composition of cryoprotective medium was recommended. The research of the process of bacterial concentrate vacuum sublimation dehydration in the layer and granular form were conducted. The research confirmed that the use of the cryofreezing and granulation can increase the number of viable microorganisms in the bacterial concentrate and reduce the drying time. Rational vacuum sublimation dehydration modes were proposed. Methods of reduc-ing the defects of the processed products and improvement of the efficiency of production facilities were specified. Quality indicators of dried bacterial concentrates were given. The results obtained allow to carry out engineering calculations

  13. Brown bear sperm double freezing: Effect of elapsed time and use of PureSperm(®) gradient between freeze-thaw cycles.

    Science.gov (United States)

    Alvarez-Rodríguez, Manuel; Alvarez, Mercedes; López-Urueña, Elena; Martínez-Rodriguez, Carmen; Borragan, Santiago; Anel-López, Luis; de Paz, Paulino; Anel, Luis

    2013-12-01

    The use of sexed spermatozoa has great potential to captive population management in endangered wildlife. The problem is that the sex-sorting facility is a long distance from the semen collection place and to overcome this difficulty two freeze-thaw cycles may be necessary. In this study, effects of refreezing on brown bear electroejaculated spermatozoa were analyzed. We carried out two experiments: (1) to assess the effects of the two freezing-thawing cycles on sperm quality and to analyze three different elapsed times between freezing-thawing cycles (30, 90 and 180 min), and (2) to analyze the use of PureSperm between freezing-thawing cycles to select a more motile and viable sperm subpopulation which better survived first freezing. The motility, viability and undamaged acrosomes were significantly reduced after the second thawing respect to first thawing into each elapsed time group, but the elapsed times did not significantly affect the viability and acrosome status although motility was damaged. Our results with the PureSperm gradient showed higher values of viability in freezability of select sample (pellet) respect to the rest of the groups and it also showed a significant decrease in the number of acrosome damaged. In summary, the double freezing of bear semen selected by gradient centrifugation is qualitatively efficient, and thus could be useful to carry out a sex-sorting of frozen-thawed bear spermatozoa before to send the cryopreserved sample to a biobank. Given the low recovery of spermatozoa after applying a selection gradient, further studies will be needed to increase the recovery rate without damaging of the cell quality. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Post Thawing Sperm Quality and Ca+2 Intensity Characters of Local Goat Sperm After Freezing by Simple Method Using Deep Freezing

    Directory of Open Access Journals (Sweden)

    Gatot Ciptadi

    2018-02-01

    Full Text Available The objective of this research was to determine the effect of the simple modified freezing method, 1°C/minute freezing rate with different diluter ration on a post-thawing quality of local goat sperm namely Peranakan Etawah (PE. This work is aimed to study the quality of post-thawing sperm and to characterize the calcium intensity profile of both fresh and post thawing goat sperm. The method used is the experimental design of a laboratory. Freezing semen was performed in 2 main temperatures of -45°C then -196°C respectively using Mr. Frosty (® System. Early Sperm characters of Ca+2 intensity was performed by Confocal Laser Scanning Microscope (CLSM through Fluo-3 staining and Ca++ intensity was analysis descriptively. The result showed that post-thawing qualities are considered as good as standard qualities, at least, more than 40% based on Indonesian National Standard (SNI, 2014. The different level diluents commercial of Andromeda used were influenced highly significant (P<0.01. The best diluents ration is 1:4 (v/v for final sperms stocked at -196°C. However freezing sperm conserved in -196°C is better than in -45°C. Meanwhile, the sperm characters of two condition showed the important variation of Ca+2 intensity, with the length of region measurement of 39.06±4.595 and 32.696±9.011 µm each.  It was concluded that the calcium intensity pattern was varied more and higher in fresh sperm than in freezing sperms. This simple modified method of a freezing system was considered as a feasible alternative method for goat semen in a reason for both for sperm post-thawing quality and practical purposes.

  15. Currency Substitution and Inflation in Peru Currency Substitution and Inflation in Peru

    OpenAIRE

    Liliana Rojas-Suarez

    1992-01-01

    This paper shows that there is a long-run relationship between the expected rate of depreciation in the black-market-exchange rate and the ratio of domestic to foreign money in Peru: that is, the hypothesis of currency substitution can explain the behavior of real holdings of money in Peru. The paper also shows that, while, the importance of currency substitution as a transmission mechanism through which domestic policies affected the dynamics of inflation was relatively small during a period...

  16. Substitution treatment for opioid addicts in Germany

    Directory of Open Access Journals (Sweden)

    Gerlach Ralf

    2007-02-01

    Full Text Available Abstract Background After a long and controversial debate methadone maintenance treatment (MMT was first introduced in Germany in 1987. The number of patients in MMT – first low because of strict admission criteria – increased considerably since the 1990s up to some 65,000 at the end of 2006. In Germany each general practitioner (GP, who has completed an additional training in addiction medicine, is allowed to prescribe substitution drugs to opioid dependent patients. Currently 2,700 GPs prescribe substitution drugs. Psychosocial care should be made available to all MMT patients. Results The results of research studies and practical experiences clearly indicate that patients benefit substantially from MMT with improvements in physical and psychological health. MMT proves successful in attaining high retention rates (65 % to 85 % in the first years, up to 50 % after more than seven years and plays a major role in accessing and maintaining ongoing medical treatment for HIV and hepatitis. MMT is also seen as a vital factor in the process of social re-integration and it contributes to the reduction of drug related harms such as mortality and morbidity and to the prevention of infectious diseases. Some 10 % of MMT patients become drug-free in the long run. Methadone is the most commonly prescribed substitution medication in Germany, although buprenorphine is attaining rising importance. Access to MMT in rural areas is very patchy and still constitutes a problem. There are only few employment opportunities for patients participating in MMT, although regular employment is considered unanimously as a positive factor of treatment success. Substitution treatment in German prisons is heterogeneous in access and treatment modalities. Access is very patchy and the number of inmates in treatment is limited. Nevertheless, substitution treatment plays a substantial part in the health care system provided to drug users in Germany. Conclusion In Germany, a

  17. Substitution treatment for opioid addicts in Germany.

    Science.gov (United States)

    Michels, Ingo Ilja; Stöver, Heino; Gerlach, Ralf

    2007-02-02

    After a long and controversial debate methadone maintenance treatment (MMT) was first introduced in Germany in 1987. The number of patients in MMT--first low because of strict admission criteria--increased considerably since the 1990s up to some 65,000 at the end of 2006. In Germany each general practitioner (GP), who has completed an additional training in addiction medicine, is allowed to prescribe substitution drugs to opioid dependent patients. Currently 2,700 GPs prescribe substitution drugs. Psychosocial care should be made available to all MMT patients. The results of research studies and practical experiences clearly indicate that patients benefit substantially from MMT with improvements in physical and psychological health. MMT proves successful in attaining high retention rates (65% to 85% in the first years, up to 50% after more than seven years) and plays a major role in accessing and maintaining ongoing medical treatment for HIV and hepatitis. MMT is also seen as a vital factor in the process of social re-integration and it contributes to the reduction of drug related harms such as mortality and morbidity and to the prevention of infectious diseases. Some 10% of MMT patients become drug-free in the long run. Methadone is the most commonly prescribed substitution medication in Germany, although buprenorphine is attaining rising importance. Access to MMT in rural areas is very patchy and still constitutes a problem. There are only few employment opportunities for patients participating in MMT, although regular employment is considered unanimously as a positive factor of treatment success. Substitution treatment in German prisons is heterogeneous in access and treatment modalities. Access is very patchy and the number of inmates in treatment is limited. Nevertheless, substitution treatment plays a substantial part in the health care system provided to drug users in Germany. In Germany, a history of substitution treatment spanning 20 years has meanwhile

  18. Freeze-tolerance of Trichinella muscle larvae in experimentally infected wild boars

    DEFF Research Database (Denmark)

    Lacour, Sandrine A.; Heckmann, Aurelie; Mace, Pauline

    2013-01-01

    served as negative controls. All wild boars were sacrificed 24 wpi. Muscle samples of 70 g were stored at -21 degrees C for 19,30 and 56h, and for 1-8 weeks. Larvae were recovered by artificial digestion. Their mobilities were recorded using Saisam (R) image analysis software and their infectivities were......Freeze-tolerance of encapsulated Trichinella muscle larvae (ML) is mainly determined by Trichinella species, but is also influenced by host species, the age of the infection and the storage time and temperature of the infected meat. Moreover, the freeze-tolerance of the encapsulated species appears...... to be correlated to the development of thick capsule walls which increases with age. An extended infection period and the muscle composition in some hosts (e.g. herbivores) may provide freeze-avoiding matrices due to high carbohydrate contents. The present experiment compares freeze-tolerance of Trichinella...

  19. Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential

    Science.gov (United States)

    Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. ¼ Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a n...

  20. Chemical freeze-out study in proton-proton collisions at RHIC and LHC energies

    International Nuclear Information System (INIS)

    Das, Sabita; Mishra, Debadeepti; Mohanty, Bedangadas; Chatterjee, Sandeep

    2016-01-01

    Particle multiplicities measured at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) facilities can be used to understand the chemical freeze-out dynamics. At chemical freeze-out (CFO), inelastic collisions cease and the freeze-out parameters can be determined using measured particle multiplicities within the framework of a statistical model. The statistical model has proven to be quite successful in describing the particle production from elementary p-p and e"+e"- collisions up to heavy-ion collisions. It helps to do a systematic study of the centrality and energy dependence of freeze-out parameters in heavy-ion collisions from lower SPS to higher LHC energies. The new data at LHC along with the RHIC data can be used to do such a systematic study in proton-proton collisions