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Sample records for freezing point depression

  1. Reproducing Black's experiments: freezing point depression and supercooling of water

    NASA Astrophysics Data System (ADS)

    Güémez, J.; Fiolhais, C.; Fiolhais, M.

    2002-01-01

    We carried out two historical experiments referred to by Joseph Black, one on freezing mixtures of salted water with ice and another on freezing supercooled pure water by a small disturbance. The results confirm thermodynamical predictions for the depression of the freezing point of salted water and for the latent heat of freezing of supercooled water respectively, which came after Black. The depression of the freezing point can hardly be fitted in the framework of the caloric theory of heat, which was taken for granted by Black, and the instantaneous freezing of supercooled water also poses some difficulties for that theory.

  2. Study of freezing-point depression of selected food extracts

    SciTech Connect

    Tanaka, Fumihiko; Murata, Satoshi; Habara, Kazuhiro; Amaratunga, K.S.P.

    1996-12-31

    The phenomenon of freezing-point depression that accompanies the solute concentration of selected food extracts was investigated to reveal the characteristics of solid-liquid phase equilibrium. The freezing curves of various food extracts did not exhibit ideal solution behavior in the higher concentration range. The experimental data were fitted to new freezing-point depression equations by the method of nonlinear least squares, and the results clearly indicated that the calculated freezing points at various concentrations were in good agreement with the experimental data. Furthermore, by using the determined parameters, the freezing ratio and the activation coefficient were derived.

  3. The Freezing Point Depression Law in Physical Chemistry.

    ERIC Educational Resources Information Center

    Franzen, Hugo F.

    1988-01-01

    Suggests a change in physical chemistry courses to use a slightly more complicated but significantly more useful generalization of the simple freezing point depression law. Lists reasons for the change and presents the treatment of solid-liquid equilibria where solid-solution is allowed. Provides a mathematical treatment. (MVL)

  4. Depression of soil moisture freezing point

    SciTech Connect

    Fedorov, V.I.

    1996-12-01

    Certain criteria for freezing temperature of clay soil have been found which are a relative moisture content at the soil liquid limit (W/W{sub L}) and maximum hydroscopic moisture (W/W{sub h}). On the strength of test data it has been established that the relative moisture content at the soil liquid limit (W/W{sub L}) may also serve as a criterion on compression pressure and resistance against shearing for soil paste with no structural binding. Linear correlation between the moisture content of natural soil and its paste -- the equation of moisture balance -- has been found which specifies a thermodynamic balance condition. The equation of moisture balance represents a whole set of properties for a certain type of soil, such as strength and compressibility. In this respect, it may be considered as a ``Soil equation`` which allows for further prognosis of its properties.

  5. Measurement of Freezing Point Depression of Selected Food Solutions

    NASA Astrophysics Data System (ADS)

    Murata, Satoshi; Tanaka, Fumihiko; Matsuoka, Takahisa

    Freezing point depression of selected food solutions were measured at various concentrations in order to reveal the characteristics of solid-liquid phase equilibrium. The measurement were carried out on a hand made apparatus that was calibrated before the measurement by some of selected reagents (acid and sugar) with known thermal properties. The results revealed that the freezing point depression of selected food solutions deviated from the behavior of the ideal solution with increasing solute concentration, so the water activity for non-ideal solution were introduced to the freezing point depression equation. Further, assuming that the heat of fusion was a equation of temperature, thus the following new equation was led, ln {(1-Xs)/(l-Xs+?·Xs + ?·Xs2)} = A(1/To - 1/Tf) - Bln(To/Tf) The goodness of fit of the equation showed the best results. Futhermore, by using the parameters a formula of freezing ratio and the relative water activities, which showed deviation from the ideal solution, were derived.

  6. Measurement of freezing point depression of water in glass capillaries and the associated ice front shape

    E-print Network

    Wan, Richard G.

    Measurement of freezing point depression of water in glass capillaries and the associated ice front of the capillary diameter. As the diameter decreases, the freezing point of water is lowered, which is called are the freezing point and the normal equilibrium temperature of the ice-water interface i.e., 273.15 K , re

  7. Correction for solute/solvent interaction extends accurate freezing point depression theory to high concentration range.

    PubMed

    Fullerton, G D; Keener, C R; Cameron, I L

    1994-12-01

    The authors describe empirical corrections to ideally dilute expressions for freezing point depression of aqueous solutions to arrive at new expressions accurate up to three molal concentration. The method assumes non-ideality is due primarily to solute/solvent interactions such that the correct free water mass Mwc is the mass of water in solution Mw minus I.M(s) where M(s) is the mass of solute and I an empirical solute/solvent interaction coefficient. The interaction coefficient is easily derived from the constant in the linear regression fit to the experimental plot of Mw/M(s) as a function of 1/delta T (inverse freezing point depression). The I-value, when substituted into the new thermodynamic expressions derived from the assumption of equivalent activity of water in solution and ice, provides accurate predictions of freezing point depression (+/- 0.05 degrees C) up to 2.5 molal concentration for all the test molecules evaluated; glucose, sucrose, glycerol and ethylene glycol. The concentration limit is the approximate monolayer water coverage limit for the solutes which suggests that direct solute/solute interactions are negligible below this limit. This is contrary to the view of many authors due to the common practice of including hydration forces (a soft potential added to the hard core atomic potential) in the interaction potential between solute particles. When this is recognized the two viewpoints are in fundamental agreement. PMID:7699200

  8. Oxygen demand of aircraft and airfield pavement deicers and alternative freezing point depressants

    USGS Publications Warehouse

    Corsi, Steven; Mericas, Dean; Bowman, George

    2012-01-01

    Aircraft and pavement deicing formulations and other potential freezing point depressants were tested for biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Propylene glycol-based aircraft deicers exhibited greater BOD5 than ethylene glycol-based aircraft deicers, and ethylene glycol-based products had lower degradation rates than propylene glycol-based products. Sodium formate pavement deicers had lower COD than acetate-based pavement deicers. The BOD and COD results for acetate-based pavement deicers (PDMs) were consistently lower than those for aircraft deicers, but degradation rates were greater in the acetate-based PDM than in aircraft deicers. In a 40-day testing of aircraft and pavement deicers, BOD results at 20°C (standard) were consistently greater than the results from 5°C (low) tests. The degree of difference between standard and low temperature BOD results varied among tested products. Freshwater BOD test results were not substantially different from marine water tests at 20°C, but glycols degraded slower in marine water than in fresh water for low temperature tests. Acetate-based products had greater percentage degradation than glycols at both temperatures. An additive component of the sodium formate pavement deicer exhibited toxicity to the microorganisms, so BOD testing did not work properly for this formulation. BOD testing of alternative freezing point depressants worked well for some, there was little response for some, and for others there was a lag in response while microorganisms acclimated to the freezing point depressant as a food source. Where the traditional BOD5 test performed adequately, values ranged from 251 to 1,580 g/kg. Where the modified test performed adequately, values of BOD28 ranged from 242 to 1,540 g/kg.

  9. Freezing point depression of water in phospholipid membranes: a solid-state NMR study.

    PubMed

    Lee, Dong-Kuk; Kwon, Byung Soo; Ramamoorthy, Ayyalusamy

    2008-12-01

    Lipid-water interaction plays an important role in the properties of lipid bilayers, cryoprotectants, and membrane-associated peptides and proteins. The temperature at which water bound to lipid bilayers freezes is lower than that of free water. Here, we report a solid-state NMR investigation on the freezing point depression of water in phospholipid bilayers in the presence and absence of cholesterol. Deuterium NMR spectra at different temperatures ranging from -75 to + 10 degrees C were obtained from fully (2)H2O-hydrated POPC (1-palmitoyl-2-oleoylphosphatidylcholine) multilamellar vesicles (MLVs), prepared with and without cholesterol, to determine the freezing temperature of water and the effect of cholesterol on the freezing temperature of water in POPC bilayers. Our 2H NMR experiments reveal the motional behavior of unfrozen water molecules in POPC bilayers even at temperatures significantly below 0 degrees C and show that the presence of cholesterol further lowered the freezing temperature of water in POPC bilayers. These results suggest that in the presence of cholesterol the fluidity and dynamics of lipid bilayers can be retained even at very low temperatures as exist in the liquid crystalline phase of the lipid. Therefore, bilayer samples prepared with a cryoprotectant like cholesterol should enable the performance of multidimensional solid-state NMR experiments to investigate the structure, dynamics, and topology of membrane proteins at a very low temperature with enhanced sample stability and possibly a better sensitivity. Phosphorus-31 NMR data suggest that lipid bilayers can be aligned at low temperatures, while 15N NMR experiments demonstrate that such aligned samples can be used to enhance the signal-to-noise ratio of is 15N chemical shift spectra of a 37-residue human antimicrobial peptide, LL-37. PMID:18991419

  10. Free Energy Perturbation Monte Carlo Simulations of Salt Influences on Aqueous Freezing Point Depression

    NASA Astrophysics Data System (ADS)

    Dick, Thomas J.; Wierzbicki, Andrzej; Madura, Jeffry D.

    Free energy perturbation Monte Carlo (FEP/MC) simulations are performed for both the liquid and solid phases of water to determine the melting temperature of several popular three and four-site water models. Gibbs free energy vs. temperature plots are constructed from the simulations to determine the melting temperature. For the liquid phase, standard FEP/MC simulations are used to calculate the free energy relative to the gas phase at multiple temperatures. The free energy of the solid phase relative to the gas phase is calculated at multiple temperatures using the lattice-coupling method. The intersection of the free energy regression lines determines the estimate of the melting temperature. Additionally, simulations were carried out for simple salt solutions to determine the freezing point depressions (FPD). The simulations reproduce the FPD as a function of salt concentration for solutions of NaCl, KCl, CaCl2, and MgCl2.

  11. Ice slurry cooling research: Microscale study of ice particles characteristics, role of freezing point depressant, and influence on slurry fluidity

    SciTech Connect

    Hayashi, K.; Kasza, K.

    2000-05-03

    The influences of freezing-point-depressants on ice slurry characteristics in the form of ice slurry fluidity and on the microscale ice particle features are studied. The results identify microscale features of ice particles such as surface roughness that greatly influence slurry fluidity that are altered favorably by the use of a freezing point depressant. The engineering of a workable and efficient ice slurry cooling system depends very strongly on the characteristics of the individual ice particles in the slurry and, in turn, on the method of ice production. Findings from this study provide guidance on the fluidity and handleability of slurry produced by several methods currently under development and already many achieved.

  12. Accuracy of two osmometers on standard samples: electrical impedance technique and freezing point depression technique

    NASA Astrophysics Data System (ADS)

    García-Resúa, Carlos; Pena-Verdeal, Hugo; Miñones, Mercedes; Gilino, Jorge; Giraldez, Maria J.; Yebra-Pimentel, Eva

    2013-11-01

    High tear fluid osmolarity is a feature common to all types of dry eye. This study was designed to establish the accuracy of two osmometers, a freezing point depression osmometer (Fiske 110) and an electrical impedance osmometer (TearLab™) by using standard samples. To assess the accuracy of the measurements provided by the two instruments we used 5 solutions of known osmolarity/osmolality; 50, 290 and 850 mOsm/kg and 292 and 338 mOsm/L. Fiske 110 is designed to be used in samples of 20 ?l, so measurements were made on 1:9, 1:4, 1:1 and 1:0 dilutions of the standards. Tear Lab is addressed to be used in tear film and only a sample of 0.05 ?l is required, so no dilutions were employed. Due to the smaller measurement range of the TearLab, the 50 and 850 mOsm/kg standards were not included. 20 measurements per standard sample were used and differences with the reference value was analysed by one sample t-test. Fiske 110 showed that osmolarity measurements differed statistically from standard values except those recorded for 290 mOsm/kg standard diluted 1:1 (p = 0.309), the 292 mOsm/L H2O sample (1:1) and 338 mOsm/L H2O standard (1:4). The more diluted the sample, the higher the error rate. For the TearLab measurements, one-sample t-test indicated that all determinations differed from the theoretical values (p = 0.001), though differences were always small. For undiluted solutions, Fiske 110 shows similar performance than TearLab. However, for the diluted standards, Fiske 110 worsens.

  13. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions.

    PubMed

    Kiyosawa, Keitaro

    2003-05-01

    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit. PMID:12834836

  14. Revised equation and table for determining the freezing point depression of H[sub 2]O-NaCl solutions

    SciTech Connect

    Bodnar, R.J. )

    1993-02-01

    Salinities of H[sub 2]O-salt inclusions are most often determined by measuring the melting temperature of ice in the inclusion and then referring this value to an equation or table describing the relationship between salinity and freezing-point depression. Generally, data for the system H[sub 2]O-NaCl are used to determine an NaCl-equivalent salinity, owing to lack of information concerning the salts (or other electrolytes) actually contributing to the freezing-point depression. The equation most often used to determine the salinity of H[sub 2]O-salt inclusions from freezing measurements is that of Potter et al (1978), which is based on a regression of data available in the literature at that time. More recently, Hall et al (1988) experimentally redetermined the ice-melting temperatures of H[sub 2]O-NaCl-KCl solutions having compositions ranging from pure water to the ternary eutectic and to each of the two binary (H[sub 2]O-NaCl and H[sub 2]O-KCl) eutectics.

  15. The nature of aqueous solutions: insights into multiple facets of chemistry and biochemistry from freezing-point depressions.

    PubMed

    Zavitsas, Andreas A

    2010-05-25

    Contrary to current widely held beliefs, many concentrated aqueous solutions of electrolytes and nonelectrolytes behave ideally. For both, the same simple equation yields mole fractions of water that are equal to the theoretical activities of water. No empirical activity coefficients or ad hoc parameters are needed. Thermodynamic hydration numbers and the number of particles produced per mole of solute are found by searching freezing-point depression measurements, as if asking the water, "How much available water solvent is left and how many solute particles are there?" The results answer questions currently under debate: Do solutes alter the nature of water outside their immediate surroundings? What is the number of ion pairs formed by various electrolytes and what affects extents of their formation? What are some factors that cause precipitation of proteins, latexes, and so forth from aqueous solutions upon addition of other solutes (Hofmeister series)? Which nonelectrolytes form aggregates in water and what are the implications? Why do different solutes affect viscosity differently? How do ion-selective channels in cell membranes function at the molecular level? PMID:20397243

  16. Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression

    SciTech Connect

    Stein, C.L.

    1985-09-01

    A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

  17. Cold Heat Storage Characteristics of O/W-type Latent Heat Emulsion Including Continuum Phase of Water Treated with a Freezing Point Depression

    NASA Astrophysics Data System (ADS)

    Inaba, Hideo; Morita, Shin-Ichi

    This paper deals with flow and cold heat storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K, Latent heat 229 kJ/kg)/water emulsion as a latent heat storage material having a low melting point. The test emulsion includes a water-urea solution as a continuum phase. The freezing point depression of the continuum phase permits enhancement of the heat transfer rate of the emulison, due to the large temperature difference between the latent heat storage material and water-urea solution. The velocity of emulsion flow and the inlet temperature of coolant in a coiled double tube heat exchanger are chosen as the experimental parameters. The pressure drop, the heat transfer coefficient of the emulsion in the coiled tube are measured in the temperture region over solid and liquid phase of the latent heat storage material. The finishing time of the cold heat storage is defined experimentally in the range of sensible and latent heat storage. It is clarified that the flow behavior of the emulsion as a non-Newtonian fluid has an important role in cold heat storage. The useful nondimentional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient and the finishing time of the cold heat storage are derived in terms of Dean number and heat capacity ratio.

  18. Freezing Point of Milk: A Natural Way to Understand Colligative Properties

    ERIC Educational Resources Information Center

    Novo, Mercedes; Reija, Belen; Al-Soufi, Wajih

    2007-01-01

    A laboratory experiment is presented in which the freezing point depression is analyzed using milk as solution. The nature of milk as a mixture of different solutes makes it a suitable probe to learn about colligative properties. The first part of the experiment illustrates the analytical use of freezing point measurements to control milk quality,…

  19. Device and method for determining freezing points

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, Balakrishnan (Inventor)

    1986-01-01

    A freezing point method and device (10) are disclosed. The method and device pertain to an inflection point technique for determining the freezing points of mixtures. In both the method and device (10), the mixture is cooled to a point below its anticipated freezing point and then warmed at a substantially linear rate. During the warming process, the rate of increase of temperature of the mixture is monitored by, for example, thermocouple (28) with the thermocouple output signal being amplified and differentiated by a differentiator (42). The rate of increase of temperature data are analyzed and a peak rate of increase of temperature is identified. In the preferred device (10) a computer (22) is utilized to analyze the rate of increase of temperature data following the warming process. Once the maximum rate of increase of temperature is identified, the corresponding temperature of the mixture is located and earmarked as being substantially equal to the freezing point of the mixture. In a preferred device (10), the computer (22), in addition to collecting the temperature and rate of change of temperature data, controls a programmable power supply (14) to provide a predetermined amount of cooling and warming current to thermoelectric modules (56).

  20. Freezing and Decorated Poisson Point Processes

    NASA Astrophysics Data System (ADS)

    Subag, Eliran; Zeitouni, Ofer

    2015-07-01

    The limiting extremal processes of the branching Brownian motion (BBM), the two-speed BBM, and the branching random walk are known to be randomly shifted decorated Poisson point processes (SDPPP). In the proofs of those results, the Laplace functional of the limiting extremal process is shown to satisfy for any nonzero, nonnegative, compactly supported, continuous function f, where is the shift operator, is a real number that depends on f, and g is a real function that is independent of f. We show that, under some assumptions, this property characterizes the structure of SDPPP. Moreover, when it holds, we show that g has to be a convolution of the Gumbel distribution with some measure. The above property of the Laplace functional is closely related to a `freezing phenomenon' that is expected to occur in a wide class of log-correlated fields, and which has played an important role in the analysis of various models. Our results shed light on this intriguing phenomenon and provide a natural tool for proving an SDPPP structure in these and other models.

  1. High-freezing-point fuels used for aviation turbine engines

    NASA Technical Reports Server (NTRS)

    Friedman, R.

    1979-01-01

    Broadened-specification aviation fuels could be produced from a greater fraction of crude source material with improvements in fuel supply and price. These fuels, particularly those with increased final boiling temperatures, would have higher freezing temperatures than current aviation turbine fuels. The higher-freezing-point fuels can be substituted in the majority of present commercial flights, since temperature data indicate that in-flight fuel temperatures are relatively mild. For the small but significant fraction of commercial flights where low fuel temperatures make higher freezing-point fuel use unacceptable, adaptations to the fuel or fuel system may be made to accommodate this fuel. Several techniques are discussed. Fuel heating is the most promising concept. One simple system design uses existing heat rejection from the fuel-lubricating oil cooler, another uses an engine-driven generator for electrical heating. Both systems offer advantages that outweigh the obvious penalties.

  2. High freezing point fuels used for aviation turbine engines

    NASA Technical Reports Server (NTRS)

    Friedman, R.

    1979-01-01

    Broadened-specification aviation fuels could be produced from a greater fraction of crude source material with improvements in fuel supply and price. These fuels, particularly those with increased final boiling temperatures, would have higher freezing temperatures than current aviation turbine fuels. For the small but significant fraction of commercial flights where low fuel temperatures make higher freezing-point fuel use unacceptable, adaptations to the fuel or fuel system may be made to accommodate this fuel. Several techniques are discussed. Fuel heating is the most promising concept. One simple design uses existing heat rejection from the fuel-lubricating oil cooler, another uses an engine-driven generator for electrical heating.

  3. Close-Packed Floating Clusters: Granular Hydrodynamics Beyond the Freezing Point? Baruch Meerson,1

    E-print Network

    Meerson, Baruch

    Close-Packed Floating Clusters: Granular Hydrodynamics Beyond the Freezing Point? Baruch Meerson,1 a simple explanation for the success of NSGH beyond the freezing point. DOI: 10.1103/PhysRevLett.91 the packing fraction approaches the freezing point value f ' 0:49 (in three dimensions) or 0.69 (in two

  4. Polystyrene Freeze Dried from Dilute Solution:ÊTg Depression and Residual Solvent

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Simon, Sindee

    2006-03-01

    The calorimetric glass transition temperature, Tg, was measured for both linear and cyclic polystyrenes freeze-dried from dilute solution in benzene for concentrations of 0.10%, 0.05% and 0.02% polymer by weight. Upon freeze-drying, Tg was found to be depressed by 4 to 15 K depending on the sample, solvent concentration, and freezing conditions. Annealing under vacuum (0.05 torr) at moderate temperatures, 40 to 140^o C, resulted in the shifts of Tg back to its bulk value and was accompanied by a decrease in sample weight. The observed weight loss is presumably due to residual solvent. The amount of solvent present in the original freeze-dried samples was determined from the weight loss observed after annealing under vacuum (0.05 torr) for one hour at 100^o C and one hour at 140^o C. The calorimetric glass temperature was measured as a function of the fraction of the residual solvent. A linear correlation was found between the Tg depression and the residual solvent concentration, in agreement with data in the literature. In addition, the structure of the freeze-dried polystyrene was examined using Fourier transform infrared spectroscopy. Results show that the recovery of Tg is not due to the structure change during annealing. We conclude that the residual solvent has a significant effect on the Tg depression observed for polymers freeze-dried from dilute solution; no depression or even a slight increase in Tg was observed in the absence of residual solvent.

  5. Understanding and Analyzing Freezing-Point Transitions of Confined Fluids within Nanopores.

    PubMed

    Shimizu, Steven; Agrawal, Kumar Varoon; O'Mahony, Marcus; Drahushuk, Lee W; Manohar, Neha; Myerson, Allan S; Strano, Michael S

    2015-09-22

    Understanding phase transitions of fluids confined within nanopores is important for a wide variety of technological applications. It is well known that fluids confined in nanopores typically demonstrate freezing-point depressions, ?Tf, described by the Gibbs-Thomson (GT) equation. Herein, we highlight and correct several thermodynamic inconsistencies in the conventional use of the GT equation, including the fact that the enthalpy of melting, ?Hm, and the solid-liquid surface energy, ?SL, are functions of pore diameter, complicating their prediction. We propose a theoretical analysis that employs the Turnbull coefficient, originally derived from metal nucleation theory, and show its consistency as a more reliable quantity for the prediction of ?Tf. This analysis provides a straightforward method to estimate ?Tf of nanoconfined organic fluids. As an example, we apply this technique to ibuprofen, an active pharmaceutical ingredient (API), and show that this theory fits well to the experimental ?Tf of nanoconfined ibuprofen. PMID:26332689

  6. Practical limitations of ITS-90 from the mercury triple point to the silver freeze point

    SciTech Connect

    Tavener, J. P.; Tavener, S. J.; Tavener, I. F.; Davies, N.

    2013-09-11

    The NPL published a forward to the ITS-90 text as follows:- 'The purpose of the ITS is to define procedures by which certain specified practical thermometers of the required quality can be calibrated in such a way that the values of temperature obtained from them can be precise and reproducible, while at the same time closely approximating the corresponding thermodynamic values.' [1]. The paper investigates the properties of thirty four lots of 6N pure metal used to make cells conforming to ITS-90 from mercury through silver over a period of twenty years. Three hundred individual cells are analysed by the impurities listed and supplied with each lot, melt and freeze curve slopes are also summarised for each lot and depressions calculated. These are then compared to the slopes and depressions suggested in the Supplementary Information for the ITS-90 and in CCT/2000-13 'Optimal Realizations'. Results are summarised, tabulated and discussed. Three lots of the thirty four were found to produce cells outside 6N expectations; however the remaining thirty one lots no matter how well or badly the accompanying certification was presented produced cells that conformed to 6N expectations as suggested in Supplementary Information to ITS-90 and CCT/2000-13.

  7. Practical limitations of ITS-90 from the mercury triple point to the silver freeze point

    NASA Astrophysics Data System (ADS)

    Tavener, J. P.; Tavener, S. J.; Tavener, I. F.; Davies, N.

    2013-09-01

    The NPL published a forward to the ITS-90 text as follows:- "The purpose of the ITS is to define procedures by which certain specified practical thermometers of the required quality can be calibrated in such a way that the values of temperature obtained from them can be precise and reproducible, while at the same time closely approximating the corresponding thermodynamic values." [1]. The paper investigates the properties of thirty four lots of 6N pure metal used to make cells conforming to ITS-90 from mercury through silver over a period of twenty years. Three hundred individual cells are analysed by the impurities listed and supplied with each lot, melt and freeze curve slopes are also summarised for each lot and depressions calculated. These are then compared to the slopes and depressions suggested in the Supplementary Information for the ITS-90 and in CCT/2000-13 "Optimal Realizations". Results are summarised, tabulated and discussed. Three lots of the thirty four were found to produce cells outside 6N expectations; however the remaining thirty one lots no matter how well or badly the accompanying certification was presented produced cells that conformed to 6N expectations as suggested in Supplementary Information to ITS-90 and CCT/2000-13.

  8. Design and evaluation of aircraft heat source systems for use with high-freezing point fuels

    NASA Technical Reports Server (NTRS)

    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.

  9. Origin of melting point depression for rare gas solids confined in carbon pores.

    PubMed

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-07-21

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ?0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point. PMID:26203042

  10. Origin of melting point depression for rare gas solids confined in carbon pores

    NASA Astrophysics Data System (ADS)

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-07-01

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ˜0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  11. An Equipment to Measure the Freezing Point of Soils under Higher Pressure

    NASA Astrophysics Data System (ADS)

    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 control electron universal testing machines. All of above mentioned advantages of this equipment ensures one to catch up the moment soil turns from the thawed state into ice and enable one to determine the freezing point experimentally by recording the temperature-time history (cooling curve) at particular points within the sample used for analysis. Therefore, this equipment has excellent characteristics such as compact construction, convenient operation, high reliability and the measuring accuracy. The authors would like to thank the following agents for their financial supports: the National Natural Science Foundation (No.41071048),Hundred Talent Young Scientists program of the Chinese Academy of Sciences granted to Dr. Zhi Wen.

  12. Effects of impurities on the freezing plateau of the triple point of water

    NASA Astrophysics Data System (ADS)

    Yan, X.; Zhang, J. T.; Duan, Y.; Wang, W.; Hao, X.

    2013-09-01

    The influence of impurities on the shape of the freezing curves of the triple point of water (TPW) in three small TPW cells was investigated using the freezing curve analysis method. We describe the procedure for preparing outer ice mantles in small TPW cells, for obtaining freezing plateaus, and for comparing the results between the old cell (s/n: 021) and the new cells (s/n: 001 and s/n: 008). The experimental results show that the maximum influence of impurities on the observed phase-transition temperature of water in the cell (s/n: 021) is approximately 0.2 mK below the peak temperature of the freezing plateau during freezing. Also, jagged temperature fluctuations were observed near the end of the freezing plateau in the old cell. However, these phenomena did not appear in the freezing plateaus of the new small cells. The equilibrium temperature realized with the old cell is 2.3 mK lower than that of the new cells, possibly due to excessive residual air. Therefore, assessing the effects of impurities on the TPW using an outer sheath method similar to that used in obtaining the fixed points of other metals is useful. Additionally, an estimated total mole fraction impurity concentration can be determined using Raoult's Law and the first cryoscopic constant for water.

  13. Realization of the Temperature Scale in the Range from 234.3 K (Hg Triple Point) to 1084.62°C (Cu Freezing Point) in Croatia

    NASA Astrophysics Data System (ADS)

    Zvizdic, Davor; Veliki, Tomislav; Grgec Bermanec, Lovorka

    2008-06-01

    This article describes the realization of the International Temperature Scale in the range from 234.3 K (mercury triple point) to 1084.62°C (copper freezing point) at the Laboratory for Process Measurement (LPM), Faculty of Mechanical Engineering and Naval Architecture (FSB), University of Zagreb. The system for the realization of the ITS-90 consists of the sealed fixed-point cells (mercury triple point, water triple point and gallium melting point) and the apparatus designed for the optimal realization of open fixed-point cells which include the gallium melting point, tin freezing point, zinc freezing point, aluminum freezing point, and copper freezing point. The maintenance of the open fixed-point cells is described, including the system for filling the cells with pure argon and for maintaining the pressure during the realization.

  14. Evaluation of methods for rapid determination of freezing point of aviation fuels

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, B.

    1982-01-01

    Methods for identification of the more promising concepts for the development of a portable instrument to rapidly determine the freezing point of aviation fuels are described. The evaluation process consisted of: (1) collection of information on techniques previously used for the determination of the freezing point, (2) screening and selection of these techniques for further evaluation of their suitability in a portable unit for rapid measurement, and (3) an extensive experimental evaluation of the selected techniques and a final selection of the most promising technique. Test apparatuses employing differential thermal analysis and the change in optical transparency during phase change were evaluated and tested. A technique similar to differential thermal analysis using no reference fuel was investigated. In this method, the freezing point was obtained by digitizing the data and locating the point of inflection. Results obtained using this technique compare well with those obtained elsewhere using different techniques. A conceptual design of a portable instrument incorporating this technique is presented.

  15. Note: equation of state and the freezing point in the hard-sphere model.

    PubMed

    Robles, Miguel; López de Haro, Mariano; Santos, Andrés

    2014-04-01

    The merits of different analytical equations of state for the hard-sphere system with respect to the recently computed high-accuracy value of the freezing-point packing fraction are assessed. It is found that the Carnahan-Starling-Kolafa and the branch-point approximant equations of state yield the best performance. PMID:24712819

  16. Nano materials for efficiently lowering the freezing point of heat transfer nanofluids

    NASA Astrophysics Data System (ADS)

    Hong, Haiping; Roy, Walter

    2007-09-01

    In this paper, we report, for the first time, the effect of the lowered freezing point in a 50% water / 50% antifreeze coolant (PAC) or 50% water / 50% ethylene glycol (EG) solution by the addition of carbon nanotubes and other particles. The experimental results indicated that the nano materials are much more efficient (hundreds fold) in lowering the freezing point than the regular ionic materials (e.g. NaCl). The possible explanation for this interesting phenomenon is the colligative property of fluid and relative small size of nano material. It is quite certain that the carbon nanotubes and metal oxide nano particles could be a wonderful candidate for the nano coolant application because they could not only increase the thermal conductivity, but also efficiently lower the freezing point of traditional coolants.

  17. Experimental results for the rapid determination of the freezing point of fuels

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, B.

    1984-01-01

    Two methods for the rapid determination of the freezing point of fuels were investigated: an optical method, which detected the change in light transmission from the disappearance of solid particles in the melted fuel; and a differential thermal analysis (DTA) method, which sensed the latent heat of fusion. A laboratory apparatus was fabricated to test the two methods. Cooling was done by thermoelectric modules using an ice-water bath as a heat sink. The DTA method was later modified to eliminate the reference fuel. The data from the sample were digitized and a point of inflection, which corresponds to the ASTM D-2386 freezing point (final melting point), was identified from the derivative. The apparatus was modifified to cool the fuel to -60 C and controls were added for maintaining constant cooling rate, rewarming rate, and hold time at minimum temperature. A parametric series of tests were run for twelve fuels with freezing points from -10 C to -50 C, varying cooling rate, rewarming rate, and hold time. Based on the results, an optimum test procedure was established. The results showed good agreement with ASTM D-2386 freezing point and differential scanning calorimetry results.

  18. Relationship Between Ice Nucleation Temperature Depression and Equilibrium Melting Points Depression of Medaka (Oryzias latipes) Embryos

    NASA Astrophysics Data System (ADS)

    Kimizuka, Norihito; Suzuki, Toru

    We measured the ice nucleation temperature depression , ?Tf , and equilibrium melting points depression, ?Tm, of Medaka (Oryzias latipes) embryos with different cryoprotectant (ethylene glycol, 1.3-propanediol, 1.4-butanediol, glycerol aqueous solutions) treatments. Our obtained results showed the good relationship between the ?Tf ,and ?Tm all samples. In addition the value of ? , which can be obtained from the linear relationship, ?Tf =? ?Tm, were confirmed to show correlation with the value of ? , as obtained by the W/O emulsion method.

  19. Mechanism to Diminish the Supercooling of the Tin Freezing Point by using Graphite Powder

    NASA Astrophysics Data System (ADS)

    Zhang, Jin Tao; Wang, Y. N.

    2008-06-01

    The formation of crystallization centers from extremely pure molten tin is normally associated with deep supercooling. This deep supercooling is inconvenient for the operation of tin freezing-point cells, especially for sealed tin fixed-point cells without a holder to facilitate removal from the furnace. Researchers of the National Institute of Metrology (NIM) intended and succeeded in reducing this deep supercooling by adding fine and pure graphite powders to tin fixed-point cells without influencing the fixed-point temperature, but the mechanism is yet to be properly clarified. The principle of heterogeneous nucleation indicates that a decrease of the contact angle of the crystalline nucleus on the substrate surface results in a significant reduction of supercooling required for initiation of nucleation. The heterogeneous theory is utilized by the authors of this paper to give a reasonable description of the mechanism of supercooling reduction by addition of graphite powder. It is demonstrated that the freezing plateau can be realized by the natural cooling of the tin cell within the furnace without using the ‘outside nucleation’ technique. The maximum temperature of the freezing curves of the tin cell with graphite powder agrees well with the reference tin cell without the graphite powder, and the cells with graphite powder show good consistency.

  20. Determination of end point of primary drying in freeze-drying process control.

    PubMed

    Patel, Sajal M; Doen, Takayuki; Pikal, Michael J

    2010-03-01

    Freeze-drying is a relatively expensive process requiring long processing time, and hence one of the key objectives during freeze-drying process development is to minimize the primary drying time, which is the longest of the three steps in freeze-drying. However, increasing the shelf temperature into secondary drying before all of the ice is removed from the product will likely cause collapse or eutectic melt. Thus, from product quality as well as process economics standpoint, it is very critical to detect the end of primary drying. Experiments were conducted with 5% mannitol and 5% sucrose as model systems. The apparent end point of primary drying was determined by comparative pressure measurement (i.e., Pirani vs. MKS Baratron), dew point, Lyotrack (gas plasma spectroscopy), water concentration from tunable diode laser absorption spectroscopy, condenser pressure, pressure rise test (manometric temperature measurement or variations of this method), and product thermocouples. Vials were pulled out from the drying chamber using a sample thief during late primary and early secondary drying to determine percent residual moisture either gravimetrically or by Karl Fischer, and the cake structure was determined visually for melt-back, collapse, and retention of cake structure at the apparent end point of primary drying (i.e., onset, midpoint, and offset). By far, the Pirani is the best choice of the methods tested for evaluation of the end point of primary drying. Also, it is a batch technique, which is cheap, steam sterilizable, and easy to install without requiring any modification to the existing dryer. PMID:20058107

  1. Optimization of thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) previously treated with freezing-point regulators using response surface methodology.

    PubMed

    Wang, Liang; Liu, Zunying; Zhao, Yuanhui; Dong, Shiyuan; Zeng, Mingyong; Yang, Huicheng

    2015-08-01

    Three freezing-point regulators (glycine, sodium chloride and D-sorbitol) were employed to optimize thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) using response surface methodology (RSM). The independent variables were glycine content (0.250-1.250 %), sodium chloride content (0.500-2.500 %) and D-sorbitol content (0.125-0.625 %) and analysis of variance showed that the effects of glycine, sodium chloride and D-sorbitol on the thermophysical properties were statistically significant (P?freezing point (T i ), unfreezable water mass fraction (W u ), apparent specific heat (C app ) and Enthalpy (H) were 0.896?~?0.999. The combined effects of these independent variables on T i , W u , C app and H were investigated. The results indicated that T i , C app and H varied curvilinearly with increasing of glycine, sodium chloride and D-sorbitol content whereas W u increased nearly linearly. Based on response plots and desirability functions, the optimum combination of process variables for Pacific white shrimp previously treated with freezing-point regulators were 0.876 % for glycine content, 2.298 % for sodium chloride content and 0.589 % for D-sorbitol content, correspondently the optimized thermophysical properties were T i , - 5.086 °C; W u , 17.222 %; C app , 41.038 J/g °C and H, 155.942 J/g, respectively. Briefly, the application of freezing-point regulators depressed T i and obtained the optimum W u , C app and H, which would be obviously beneficial for the exploitation of various thermal processing and food storage. PMID:26243904

  2. Realization of tin freezing point using a loop heat pipe-based hydraulic temperature control technique

    NASA Astrophysics Data System (ADS)

    Joung, Wukchul; Gam, Kee Sool; Kim, Yong-Gyoo

    2015-10-01

    In this work, the freezing point of tin (Sn FP) was realized by inside nucleation where the supercooling of tin and the reheating of the sample after the nucleation were achieved without extracting the cell from an isothermal apparatus. To this end, a novel hydraulic temperature control technique, which was based on the thermo-hydraulic characteristics of a pressure-controlled loop heat pipe (LHP), was employed to provide a slow cooling of the sample for deep supercooling and fast reheating after nucleation to minimize the amount of initial freeze of the sample. The required temperature controls were achieved by the active pressure control of a control gas inside the compensation chamber of the pressure-controlled LHP, and slow cooling at??-0.05 K min-1 for the deep supercooling of tin and fast heating at 2 K min-1 for reheating the sample after nucleation was attained. Based on this hydraulic temperature control technique, the nucleation of tin was realized at supercooling of around 19 K, and a satisfactorily fast reheating of the sample to the plateau-producing temperature (i.e. 0.5 K below the Sn FP) was achieved without any temperature overshoots of the isothermal region. The inside-nucleated Sn FP showed many desirable features compared to the Sn FP realized by the conventional outside nucleation method. The longer freezing plateaus and the better immersion characteristics of the Sn FP were obtained by inside nucleation, and the measured freezing temperature of the inside-nucleated Sn FP was as much as 0.37 mK higher than the outside-nucleated Sn FP with an expanded uncertainty of 0.19 mK. Details on the experiment are provided and explanations for the observed differences are discussed.

  3. Melting point depression of Al clusters generated during the early stages of film growth: Nanocalorimetry measurements

    E-print Network

    Allen, Leslie H.

    Melting point depression of Al clusters generated during the early stages of film growth in microelectronics: i melt- ing point depression as related to the Al reflow process,7­10 ii coalescence during been learned about the size-dependent melting point depression in recent times. Studies in model

  4. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels.

    PubMed

    Jaramillo-Ochoa, Liliana; Ramirez-Gutierrez, Cristian F; Sánchez-Moguel, Alonso; Acosta-Osorio, Andrés; Rodriguez-Garcia, Mario E

    2015-01-01

    This work is focused in the development of a modulated optical transmission system with temperature control to determine the thermal properties of biodiesels such as the cloud and freezing points. This system is able to determine these properties in real time without relying on the operator skills as indicated in the American Society for Testing Materials (ASTM) norms. Thanks to the modulation of the incident laser, the noise of the signal is reduced and two information channels are generated: amplitude and phase. Lasers with different wavelengths can be used in this system but the sample under study must have optical absorption at the wavelength of the laser. PMID:25638112

  5. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels

    NASA Astrophysics Data System (ADS)

    Jaramillo-Ochoa, Liliana; Ramirez-Gutierrez, Cristian F.; Sánchez-Moguel, Alonso; Acosta-Osorio, Andrés; Rodriguez-Garcia, Mario E.

    2015-01-01

    This work is focused in the development of a modulated optical transmission system with temperature control to determine the thermal properties of biodiesels such as the cloud and freezing points. This system is able to determine these properties in real time without relying on the operator skills as indicated in the American Society for Testing Materials (ASTM) norms. Thanks to the modulation of the incident laser, the noise of the signal is reduced and two information channels are generated: amplitude and phase. Lasers with different wavelengths can be used in this system but the sample under study must have optical absorption at the wavelength of the laser.

  6. Ultra-high temperature isothermal furnace liners (IFLS) for copper freeze point cells

    NASA Astrophysics Data System (ADS)

    Dussinger, P. M.; Tavener, J. P.

    2013-09-01

    Primary Laboratories use large fixed-point cells in deep calibration furnaces utilizing heat pipes to achieve temperature uniformity. This combination of furnace, heat pipe, and cell gives the smallest of uncertainties. The heat pipe, also known as an isothermal furnace liner (IFL), has typically been manufactured with Alloy 600/601 as the envelope material since the introduction of high temperature IFLs over 40 years ago. Alloy 600/601 is a widely available high temperature material, which is compatible with Cesium, Potassium, and Sodium and has adequate oxidation resistance and reasonable high temperature strength. Advanced Cooling Technologies, Inc. (ACT) Alloy 600/Sodium IFLs are rated to 1100°C for approximately 1000 hours of operation (based on creep strength). Laboratories interested in performing calibrations and studies around the copper freezing point (1084.62°C) were frustrated by the 1000 hours at 1100°C limitation and the fact that expensive freeze-point cells were getting stuck and/or crushed inside the IFL. Because of this growing frustration/need, ACT developed an Ultra High Temperature IFL to take advantage of the exceptional high temperature strength properties of Haynes 230.

  7. Improvements in the realization of the ITS-90 over the temperature range from the melting point of gallium to the freezing point of silver at NIM

    SciTech Connect

    Sun, J.; Zhang, J. T.; Ping, Q.

    2013-09-11

    The temperature primary standard over the range from the melting point of gallium to the freezing point of silver in National institute of Metrology (NIM), China, was established in the early 1990s. The performance of all of fixed-point furnaces degraded and needs to be updated due to many years of use. Nowadays, the satisfactory fixed point materials can be available with the development of the modern purification techniques. NIM plans to use a group of three cells for each defining fixed point temperature. In this way the eventual drift of individual cells can be evidenced by periodic intercomparison and this will increase the reliability in disseminating the ITS-90 in China. This article describes the recent improvements in realization of ITS-90 over temperature range from the melting point of gallium to the freezing point of silver at NIM. Taking advantages of the technological advances in the design and manufacture of furnaces, the new three-zone furnaces and the open-type fixed points were developed from the freezing point of indium to the freezing point of silver, and a furnace with the three-zone semiconductor cooling was designed to automatically realize the melting point of gallium. The reproducibility of the new melting point of gallium and the new open-type freezing points of In, Sn, Zn. Al and Ag is improved, especially the freezing points of Al and Ag with the reproducibility of 0.2mK and 0.5mK respectively. The expanded uncertainty in the realization of these defining fixed point temperatures is 0.34mK, 0.44mK, 0.54mK, 0.60mK, 1.30mK and 1.88mK respectively.

  8. Prospective Chemistry Teachers' Misconceptions about Colligative Properties: Boiling Point Elevation and Freezing Point Depression

    ERIC Educational Resources Information Center

    Pinarbasi, Tacettin; Sozbilir, Mustafa; Canpolat, Nurtac

    2009-01-01

    This study aimed at identifying prospective chemistry teachers' misconceptions of colligative properties. In order to fulfill this aim, a diagnostic test composed of four open-ended questions was used. The test was administered to seventy-eight prospective chemistry teachers just before qualifying to teaching in secondary schools. Nine different…

  9. When hot water freezes before cold

    E-print Network

    J. I. Katz

    2006-04-27

    I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the temperature of the freezing front, and thereby reduce the temperature gradient and heat flux, slowing the progress of the front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

  10. When hot water freezes before cold

    E-print Network

    Katz, J I

    2006-01-01

    I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the temperature of the freezing front, and thereby reduce the temperature gradient and heat flux, slowing the progress of the front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

  11. Modeling salt precipitation from brines on Mars: Evaporation versus freezing origin for soil salts

    E-print Network

    Winglee, Robert M.

    they are among the most hygroscopic salts known (Gough et al., 2011), and can depress the freezing point of water found that $1.3 wt.% H2O is held in hydrated salts if WCL solutions freeze. Given minimum water contentsModeling salt precipitation from brines on Mars: Evaporation versus freezing origin for soil salts

  12. Depression of melting point for protective aluminum oxide films

    NASA Astrophysics Data System (ADS)

    Dreizin, E. L.; Allen, D. J.; Glumac, N. G.

    2015-01-01

    The protective aluminum oxide film naturally formed on a surface of aluminum has a thickness in the range of 3-5 nm. Its melting causes loss of its continuity, which may significantly affect the ignition and combustion processes and their relative time scales. Melting of the alumina film also plays an important role when aluminum powders are used to prepare composites and/or being sintered. This letter quantifies depression of the melting point of an alumina film based on its nano-meter thickness. A theoretical estimate is supported by experiments relying on a detected change in the optical properties of naturally oxidized aluminum particles heated in an inert environment.

  13. The initial freezing point temperature of beef rises with the rise in pH: a short communication.

    PubMed

    Farouk, M M; Kemp, R M; Cartwright, S; North, M

    2013-05-01

    This study tested the hypothesis that the initial freezing point temperature of meat is affected by pH. Sixty four bovine M. longissimus thoracis et lumborum were classified into two ultimate pH groups: low (<5.8) and high pH (>6.2) and their cooling and freezing point temperatures were determined. The initial freezing temperatures for beef ranged from -0.9 to -1.5°C (?=0.6°C) with the higher and lower temperatures associated with high and low ultimate pH respectively. There was a significant correlation (r=+0.73, P<0.01) between beef pH and freezing point temperature in the present study. The outcome of this study has implications for the meat industry where evidence of freezing (ice formation) in a shipment as a result of high pH meat could result in a container load of valuable chilled product being downgraded to a lower value frozen product. PMID:23410892

  14. Depression

    MedlinePLUS

    ... Stay Connected Home » Depression Heath and Aging Depression What Causes Depression? What to Look For Getting ... feel better with the right treatment. What Causes Depression? There is no one cause of depression. For ...

  15. Working and Non-Working University Students: Anxiety, Depression, and Grade Point Average

    ERIC Educational Resources Information Center

    Mounsey, Rebecca; Vandehey, Michael A.; Diekhoff, George M.

    2013-01-01

    This study explored the differences between 110 working and non-working students in terms of mental health, academic achievement, and perceptions about student employment. Anxiety and depression were measured by the Beck Anxiety Inventory and the Beck Depression Inventory-II. Academic achievement was measured by grade point average. Perceptions of…

  16. Supercooling Point Plasticity During Cold Storage in the Freeze-tolerant Sugarbeet Root Maggot Tetanops myopaeformis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugarbeet root maggot, Tetanops myopaeformis (Röder), overwinters as a freeze-tolerant 3rd instar larva. While most larvae are thought to overwinter for only one year, some may exhibit prolonged diapause in the field. In the laboratory, they can live for over five years using a combination of ...

  17. Depression

    MedlinePLUS

    ... a Psychiatrist Patients & Families All Topics Help With Depression Curated and updated for the community by APA Topic Information Depression (major depressive disorder) is a common and serious ...

  18. Drought increases freezing tolerance of both leaves and xylem of Larrea tridentatapce_2224 43..51

    E-print Network

    Pockman, William T.

    Drought increases freezing tolerance of both leaves and xylem of Larrea tridentatapce_2224 43 decreasing it in the xylem, potentially creating a mismatch between water supply and demand. To test exchange, cell death, freezing point depression and leaf-specific xylem hydraulic conductance (kl). Drought

  19. Ice Surface Entropy Induction by Humidity or How Humidity Prompts Freezing

    E-print Network

    Jose Luis Perez-Diaz; Marco Antonio Alvarez-Valenzuela; Juan Sanchez-Garcia-Casarrubios; Sergio Jimenez-Lopez

    2015-09-22

    In this work we measured Surface Energy and Freezing Temperature of supercooled water droplets in air. We find that freezing of water droplets is triggered at the water-air interface and that freezing progresses faster on the surface than in the bulk. The Freezing Point of water droplets is strongly depressed by dryness in air and how humidity triggers freezing. Additionally it is shown to be a Surface phenomenon related to a transfer of Entropy from water vapour to the surface of ice.

  20. Depression

    MedlinePLUS

    ... version of this page please turn Javascript on. Depression About Depression Click for more information Everyone feels blue or ... disorder," or "clinical depression." Click for more information Depression in Older Adults Important life changes that happen ...

  1. Molecular Dynamics Study of Freezing Point and Solid-Liquid Interfacial Free Energy of Stockmayer Fluids

    SciTech Connect

    Wang, J.; Apte, Pankaj; Morris, James R; Zeng, X.C.

    2013-01-01

    Freezing temperatures of Stockmayer fluids with different dipolar strength at zero pressure are estimated and computed using three independent molecular-dynamics (MD) simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature (NPT) two phase coexistence method, and the constant-pressure and constant-enthalpy (NPH) coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with a reduced dipole moment is 0.656 0.001, 0.726 0.002 and 0.835 0.005, respectively. The freezing temperature increases with the dipolar strength. The solid-liquid interfacial free energies of the (111), (110) and (100) interface are calculated for the first time using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, that is, .

  2. Depression

    MedlinePLUS

    ... and negative thinking worse. Back Continue Depression Can Go Unrecognized People with depression may not realize they ... themselves or who have eating disorders or who go through extreme mood changes may have unrecognized depression. ...

  3. Depression Treatment for Impoverished Mothers by Point-of-Care Providers: A Randomized Controlled Trial

    PubMed Central

    Segre, Lisa S.; Brock, Rebecca L.; O’Hara, Michael W.

    2015-01-01

    Objective Depression in low-income, ethnic-minority women of childbearing age is prevalent and compromises infant and child development. Yet numerous barriers prevent treatment delivery. Listening Visits (LV), an empirically supported intervention developed for delivery by British home-visiting nurses, could address this unmet mental health need. This randomized controlled trial evaluated the effectiveness of LV delivered at a woman’s usual point-of-care, including home-visits or an ob-gyn office. Method Listening Visits were delivered to depressed pregnant women or mothers of young children by their point-of-care provider (e.g., home visitor or physician’s assistant), all of whom had low levels of prior counseling experience. Three quarters of the study’s participants were low-income. Of those who reported ethnicity, all identified themselves as minorities. Participants from four study sites (N = 66) were randomized in a 2:1 ratio, to LV or a wait-list control group (WLC). Assessments, conducted at baseline and 8 weeks, evaluated depression, quality of life, and treatment satisfaction. Results Depressive severity, depressive symptoms, and quality of life significantly improved among LV recipients as compared to women receiving standard social/health services. Women valued LV as evidenced by their high attendance rates and treatment satisfaction ratings. Conclusions In a stepped model of depression care, LV can provide an accessible, acceptable, and effective first-line treatment option for at-risk women who otherwise are unlikely to receive treatment. PMID:25486371

  4. Depression, posttraumatic stress disorder, and grade point average among student servicemembers and veterans.

    PubMed

    Bryan, Craig J; Bryan, AnnaBelle O; Hinkson, Kent; Bichrest, Michael; Ahern, D Aaron

    2014-01-01

    The current study examined relationships among self-reported depression severity, posttraumatic stress disorder (PTSD) symptom severity, and grade point average (GPA) among student servicemembers and veterans. We asked 422 student servicemembers and veterans (72% male, 86% Caucasian, mean age = 36.29 yr) to complete an anonymous online survey that assessed self-reported GPA, depression severity, PTSD severity, and frequency of academic problems (late assignments, low grades, failed exams, and skipped classes). Female respondents reported a slightly higher GPA than males (3.56 vs 3.41, respectively, p = 0.01). Depression symptoms (beta weight = -0.174, p = 0.03), male sex (beta weight = 0.160, p = 0.01), and younger age (beta weight = 0.155, p = 0.01) were associated with lower GPA but not PTSD symptoms (beta weight = -0.040, p = 0.62), although the interaction of depression and PTSD symptoms showed a nonsignificant inverse relationship with GPA (beta weight = -0.378, p = 0.08). More severe depression was associated with turning in assignments late (beta weight = 0.171, p = 0.03), failed exams (beta weight = 0.188, p = 0.02), and skipped classes (beta weight = 0.254, p = 0.01). The relationship of depression with self-reported GPA was mediated by frequency of failed examns. Results suggest that student servicemembers and veterans with greater emotional distress also report worse academic performance. PMID:25436619

  5. Depression

    MedlinePLUS

    Depression is a serious medical illness that involves the brain. It's more than just a feeling of ... million people in the United States who have depression, the feelings do not go away. They persist ...

  6. High-speed Imaging of Freezing Drops: Investigating the Role of Point-like Contact in Heterogeneous Ice Nucleation

    NASA Astrophysics Data System (ADS)

    Gurganus, C.; Charnawskas, J.; Shaw, R. A.; Kostinski, A. B.

    2013-12-01

    Formation of ice by contact nucleation remains enigmatic and the possible role of the three-phase boundary (i.e., liquid water-ice-aerosol contact line) is still undetermined. Because aerosol size, surface area, composition and exact region of contact remain difficult to measure, we examine a simpler geometry with a spherical cap droplet resting on a substrate. In this configuration, the droplet simultaneously experiences a two-phase immersion region and a three phase contact region around the perimeter of the droplet. Utilizing high speed imaging of the droplet-substrate plane, we are able to identify nucleation sites in individual droplets. This technique allows for a spatial distribution of freezing sites in addition to a freezing temperature distribution. Our initial study indicated no preference for nucleation originating at the three phase boundary for an atomically smooth homogenous substrate [1]. The nucleation site distribution agreed well with the stochastic view in that the germ sites are distributed uniformly over the surface area. In that study we minimized the thermal variation (?T) across a droplet during cooling to prevent biased observations. We also compared ?T for several experiments in literature using a simple formulation of droplet size (r) and cooling rate (?). Large variations in some experiments could possibly explain observed 'contact nucleation' events in the laboratory as artifacts of radial thermal variations during droplet cooling. As a continuation of this study, we redesigned our system to enable much greater substrate cooling rates, but these experiments too revealed no preference for nucleation in the contact mode. Thermal modeling of the new system confirmed that while a vertical thermal gradient does develop within the droplet, no horizontal gradient is induced in the drop near the substrate. This result argues against a thermodynamic bias toward contact nucleation in substrate cooled geometries. Another possible explanation for this contact phenomenon comes in a lowering of the energy barrier for nucleation due to the existence of a line tension at the point of contact. A scale analysis of the line and surface energy values available in the literature suggests that line tension may become dominant below length scales of ~10 nm [1]. From this simple result we postulate that 'point-like' surface features might play an important role at the three phase boundary. To mimic these features on substrates we introduce chemical and mechanical processes to enhance substrate surface roughness. Using these new substrates we repeat our experimental procedure to compare effectiveness of the immersion (two phase) and contact (three phase) regions for a variety of surface topologies. Here we report the initial findings from this work. 1. Gurganus, C.; Kostinski, A. B.; Shaw, R. A., Fast Imaging of Freezing Drops: No Preference for Nucleation at the Contact Line. J Phys Chem Lett 2011, 2 (12) Identifying nucleation sites with two high speed cameras.

  7. Negative pressures and melting point depression in oxide-coated liquid metal droplets

    NASA Technical Reports Server (NTRS)

    Spaepen, F.; Turnbull, D.

    1979-01-01

    Negative pressures and melting point depression in oxide-coated liquid metal droplets are studied. The calculation presented show the existence of large negative pressures when the oxide coating is thick enough. The change in the melting point caused by these negative pressures should be considered in studies of homogeneous crystal nucleation. Furthermore, since the negative pressure raises the entropy of the melt, it increases the entropy loss at the crystal-melt interface; the resulting increase of the surface tension could have a large effect on the homogeneous nucleation frequency.

  8. Freezing in confined geometries

    NASA Technical Reports Server (NTRS)

    Sokol, P. E.; Ma, W. J.; Herwig, K. W.; Snow, W. M.; Wang, Y.; Koplik, Joel; Banavar, Jayanth R.

    1992-01-01

    Results of detailed structural studies, using elastic neutron scattering, of the freezing of liquid O2 and D2 in porous vycor glass, are presented. The experimental studies have been complemented by computer simulations of the dynamics of freezing of a Lennard-Jones liquid in narrow channels bounded by molecular walls. Results point to a new simple physical interpretation of freezing in confined geometries.

  9. Periodic ice banding in freezing colloidal dispersions.

    PubMed

    Anderson, Anthony M; Worster, M Grae

    2012-12-01

    Concentrated colloidal alumina dispersions were frozen in a directional solidification apparatus that provides independent control of the freezing rate and temperature gradient. Two distinct steady-state modes of periodic ice banding were observed in the range of freezing rates examined. For each mode, the wavelength between successive bands of segregated ice decreases with increasing freezing rate. At low freezing rates (0.25-3 ?m s(-1)), the ice segregates from the suspension into ice lenses, which are cracklike in appearance, and there is visible structure in the layer of rejected particles in the unfrozen region ahead of the ice lenses. In this regime, we argue that compressive cryosuction forces lead to the irreversible aggregation of the rejected particles into a close-packed cohesive layer. The temperature in the aggregated layer is depressed below the bulk freezing point by more than 2 °C before the ice lenses are encountered; moreover, this undercooled region appears as a light-colored layer. The magnitude of the undercooling and the color change in this region both suggest the presence of pore ice and the formation of a frozen fringe. The possibility of a frozen fringe is supported by a quantitative model of the freezing behavior. At intermediate freezing rates, around 4 ?m s(-1), the pattern of ice segregation is disordered, coinciding with the disappearance of the dark- and light-colored layers. Finally, at high freezing rates (5-10 ?m s(-1)), there is a new mode of periodic ice banding that is no longer cracklike and is absent of any visible structure in the suspension ahead of the ice bands. We discuss the implications of our experimental findings for theories of ice lensing. PMID:23110707

  10. Depression.

    ERIC Educational Resources Information Center

    Strock, Margaret

    Approximately ten percent of the population suffers from a depressive illness each year. Although the economic cost is high, the cost in human suffering is immeasurable. To help educate the population about this disorder, this paper presents a definition of depression and its common manifestations. The symptoms that people often experience are…

  11. Size-dependent melting point depression of nanostructures: Nanocalorimetric measurements M. Zhang, M. Yu. Efremov, F. Schiettekatte, E. A. Olson, A. T. Kwan, S. L. Lai, T. Wisleder,

    E-print Network

    Allen, Leslie H.

    Size-dependent melting point depression of nanostructures: Nanocalorimetric measurements M. Zhang in terms of existing melting point depression models. Excellent agreement with the homogeneous melting depression--small particles have a lower melting point than bulk material.3­5 This results from the increas

  12. Depression.

    PubMed

    Weissman, Myrna

    2009-04-01

    This is an invited article on how my career as an epidemiologist studying depression unfolded. The role of the Civil Rights movement in opening the PhD doors to women at Yale began my career. The unfolding of depression studies are described. These studies included a clinical trial of medication and what later was known as interpersonal psychotherapy (IPT), the first community survey of psychiatric disorder, family genetic and brain imaging studies or depression and anxiety disorders. I hope the new generation will have the wonderful opportunities I have had. PMID:19344866

  13. Depressants

    MedlinePLUS

    ... symptoms when trying to quit. Other long-term effects include: impaired sexual function insomnia and other sleep problems breathing problems convulsions (similar to seizures) depression and other mental health issues Continue Other Possible Problems Taking too much ...

  14. A molecular simulation study of freezing/melting phenomena for Lennard-Jones methane in cylindrical nanoscale pores

    SciTech Connect

    Maddox, M.W.; Gubbins, K.E.

    1997-12-01

    A combination of grand canonical Monte Carlo and molecular dynamics simulation techniques are used to study the freezing and melting of Lennard-Jones methane in several different cylindrical pores. Two different types of pore wall are considered; a strongly attractive wall, and a weakly attractive wall, each with pore diameters in the range 1.5{endash}3.5 nm. Freezing point depression is observed in the case of the weakly attractive pores, in agreement with several experimental studies. Freezing point elevation is observed at the walls of the strongly attractive pore, but freezing point depression occurs at the center of such pores, due to geometrical constraints. {copyright} {ital 1997 American Institute of Physics.}

  15. Experimental and analytical investigation of a freezing point depressant fluid ice protection system. M.S. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Albright, A. E.

    1984-01-01

    A glycol-exuding porous leading edge ice protection system was tested in the NASA Icing Research Tunnel. Stainless steel mesh, laser drilled titanium, and composite panels were tested on two general aviation wing sections. Two different glycol-water solutions were evaluated. Minimum glycol flow rates required for anti-icing were obtained as a function of angle of attack, liquid water content, volume median drop diameter, temperature, and velocity. Ice accretions formed after five minutes of icing were shed in three minutes or less using a glycol fluid flow equal to the anti-ice flow rate. Two methods of predicting anti-ice flow rates are presented and compared with a large experimental data base of anti-ice flow rates over a wide range of icing conditions. The first method presented in the ADS-4 document typically predicts flow rates lower than the experimental flow rates. The second method, originally published in 1983, typically predicts flow rates up to 25 percent higher than the experimental flow rates. This method proved to be more consistent between wing-panel configurations. Significant correlation coefficients between the predicted flow rates and the experimental flow rates ranged from .867 to .947.

  16. Magneto-caloric effect of a Gd50Co50 amorphous alloy near the freezing point of water

    NASA Astrophysics Data System (ADS)

    Xia, L.; Wu, C.; Chen, S. H.; Chan, K. C.

    2015-09-01

    In the present work, we report the magneto-caloric effect (MCE) of a binary Gd50Co50 amorphous alloy near the freezing temperature of water. The Curie temperature of Gd50Co50 amorphous ribbons is about 267.5 K, which is very close to room temperature. The peak value of the magnetic entropy change (-?Smpeak) and the resulting adiabatic temperature rise (?Tad.) of the Gd50Co50 amorphous ribbons is much higher than that of any other amorphous alloys previously reported with a Tc near room temperature. On the other hand, although the -?Smpeak of Gd50Co50 amorphous ribbons is not as high as those of crystalline alloys near room temperature, its refrigeration capacity (RC) is still much larger than the RC values of these crystalline alloys. The binary Gd50Co50 amorphous alloy provides a basic alloy for developing high performance multi-component amorphous alloys near room temperature.

  17. Final report on COOMET.T-S1. Comparison of type S thermocouples at the freezing points of zinc, aluminium and copper 2014—2015

    NASA Astrophysics Data System (ADS)

    Pokhodun, A. I.; Ivanova, A. G.; Duysebayeva, K. K.; Ivanova, K. P.

    2015-01-01

    Regional comparison of type S thermocouples at the freezing points of zinc, aluminium and copper was initiated by COOMET TC1.1-10 (the technical committee of COOMET `Thermometry and thermal physics'). Three NMI take part in COOMET regional comparison: D I Mendeleev Institute for Metrology (VNIIM) (Russian Federation), National Scientific Centre (Institute of Metrology) (NSC IM, Ukraine), Republic State Enterprise (Kazakhstan Institute of Metrology) (KazInMetr, Republic of Kazakhstan). VNIIM (Russia) was chosen as the coordinator-pilot of the regional comparison. A star type comparison was used. The participants: KazInMetr and NSC IM constructed the type S thermocouples and calibrated them in three fixed points: zinc, aluminum and copper points, using methods of ITS-90 fixed point realizations. The thermocouples have been sent to VNIIM together with the results of the calibration at three fixed points, with the values of the inhomogeneity at temperature 200 °C and the uncertainty evaluations of the results. For calibration of thermocouples the same VNIIM fixed points cells were used. Participating laboratories repeated the calibration of thermocouples after its returning in zinc, aluminum and copper points to determine the stability of its results. In result of the comparison was to evaluate the equivalence of the type S thermocouples calibration in fixed points by NMIs to confirm corresponding lines of international website for NMI's Calibration and Measurement Capabilities (CMC). This paper is the final report of the comparison including analysis of the uncertainty of measurement results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT WG-KC, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  18. MedLink: A Mobile Intervention to Address Failure Points in the Treatment of Depression in General Medicine

    PubMed Central

    Mohr, David C.; Stiles-Shields, Colleen; Brenner, Christopher; Palac, Hannah; Montague, Enid; Kaiser, Susan M.; Carty-Fickes, Eric; Duffecy, Jenna

    2015-01-01

    Major depression is common, and imposes a high burden in terms of cost, morbidity, and suffering. Most people with depression are treated in general medicine using antidepressant medication. Outcomes are poor due to failure points across the care system, including patient non-adherence, failure of physicians to optimize the treatment regimens, and lack of patient-physician communication. This study reports on the 4-week pilot deployment of MedLink, a mobile intervention aimed at systemically addressing each of these failure points. A mobile app provides the patient with information and collects data on symptoms and side-effects. A cellularly enabled pill bottle monitors medication adherence. Data from these are provided to the physician and patient to foster communication and medication adjustments. Usability evaluation was generally favorable. Medication adherence rates in this first deployment were high with no patients discontinuing, and 84% of doses taken. Depressive symptom severity was significantly reduced. This study supports the use of a comprehensive, systemic approach to mHealth solutions to enhance processes of care for depression by general medicine physicians.

  19. Ground freezing

    SciTech Connect

    Kinosita, S.; Fukuda, M.

    1985-01-01

    The authors' discuss how artificial freezing of the ground has been used in increasingly in the last few decades to stabilize earth materials and control groundwater seepage in geotechnical construction. Emphasis is on the relation between theory, design and application of ground freezing in construction: Thermal properties and processes in earth materials; Frost action; Mechanical properties and processes in earth materials; Engineering design and case histories (tunnels, pipelines, foundations, slopes, LNG tanks, shafts).

  20. Liquidus Temperature Depression in Cryolitic Melts

    NASA Astrophysics Data System (ADS)

    Solheim, Asbjørn

    2012-08-01

    The electrolyte in Hall-Héroult cells for the manufacture of primary aluminum nominally contains only cryolite (Na3AlF6) with additions of AlF3, CaF2, and Al2O3. However, impurities are present, entering the process with the feedstock. The effect on the liquidus temperature by the impurities cannot be calculated correctly by the well-known equation for freezing-point depression in binary systems simply because the electrolyte cannot be regarded as a binary system. By extending the equation for freezing-point depression to the ternary system NaF-AlF3-B, it appeared that the acidity of the impurity B plays a major role. Some calculations were made using an ideal Temkin model, and for most types of impurities, the effect on the liquidus temperature will be larger in an industrial electrolyte than what can be estimated from the equation for freezing-point depression in cryolite. Experimental data on the liquidus temperature in the system Na3AlF6-AlF3-Al2O3-CaF2-MgF2 show that the effect of MgF2 on the liquidus temperature increases strongly with decreasing NaF/AlF3 molar ratio, and it is suggested that MgF2 forms an anion complex, probably MgF{4/2-}.

  1. Bjorken expansion with gradual freeze out

    E-print Network

    V. K. Magas; L. P. Csernai; E. Molnar

    2007-02-27

    The freeze out of the expanding systems, created in relativistic heavy ion collisions, will be discussed. We combine kinetic freeze out equations with Bjorken type system expansion into a unified model. Such a model is a more physical generalization of the earlier simplified non-expanding freeze out models. We shall see that the basic freeze out features, pointed out in the earlier works, are not smeared out by the expansion.

  2. Autobiographical Memory and Depression in the Later Age: The Bump Is a Turning Point

    ERIC Educational Resources Information Center

    Gidron, Yori; Alon, Shirly

    2007-01-01

    This preliminary study integrated previous findings of the distribution of autobiographical memories in the later age according to their age of occurrence, with the overgeneral memory bias predictive of depression. Twenty-five non-demented, Israeli participants between 65-89 years of age provided autobiographical memories to 4 groups of word cues…

  3. Poly(vinyl methyl ether) hydrogels at temperatures below the freezing point of water-molecular interactions and states of water.

    PubMed

    Pastorczak, Marcin; Dominguez-Espinosa, Gustavo; Okrasa, Lidia; Pyda, Marek; Kozanecki, Marcin; Kadlubowski, Slawomir; Rosiak, Janusz M; Ulanski, Jacek

    2014-01-01

    Water interacting with a polymer reveals a number of properties very different to bulk water. These interactions lead to the redistribution of hydrogen bonds in water. It results in modification of thermodynamic properties of water and the molecular dynamics of water. That kind of water is particularly well observable at temperatures below the freezing point of water, when the bulk water crystallizes. In this work, we determine the amount of water bound to the polymer and of the so-called pre-melting water in poly(vinyl methyl ether) hydrogels with the use of Raman spectroscopy, dielectric spectroscopy, and calorimetry. This analysis allows us to compare various physical properties of the bulk and the pre-melting water. We also postulate the molecular mechanism responsible for the pre-melting of part of water in poly(vinyl methyl ether) hydrogels. We suggest that above -60 °C, the first segmental motions of the polymer chain are activated, which trigger the process of the pre-melting. PMID:25100897

  4. Satellite freeze forecast system

    NASA Technical Reports Server (NTRS)

    Martsolf, J. D. (principal investigator)

    1983-01-01

    Provisions for back-up operations for the satellite freeze forecast system are discussed including software and hardware maintenance and DS/1000-1V linkage; troubleshooting; and digitized radar usage. The documentation developed; dissemination of data products via television and the IFAS computer network; data base management; predictive models; the installation of and progress towards the operational status of key stations; and digital data acquisition are also considered. The d addition of dew point temperature into the P-model is outlined.

  5. Synergistic impacts of land-use change and soil property variation on non-point source nitrogen pollution in a freeze-thaw area

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Huang, Haobo; Hao, Fanghua; Guo, Bobo

    2013-07-01

    Quantifying the non-point source (NPS) nitrogen pollution response to the varied land-use and soil properties in highly agricultural regions is critical for the proper management of NPS pollution. This study simulated the NPS nitrogen loading responses to variations of land-use and soil from 1979 to 2009. The Soil and Water Assessment Tool (SWAT) was used to model the NPS organic nitrogen and nitrate loading in a freeze-thaw area in northeast China. The temporal-spatial simulations of land-use in four periods indicated that the NPS nitrogen loading responded to the disappearance of wetlands and the conversion of uplands to paddy rice. After updating the soil data, the watershed NPS nitrogen loading decreased, and the spatial distribution of the loading indicated that the NPS organic nitrogen was more sensitive than was the nitrate to soil variation. F-tests were employed to assess the significance of each of the predictor variables in five types of scenarios. Overall, the results indicate that the watershed NPS nitrogen loading is sensitive to changes of soil and land-use, but soil changes have a more significant impact. The results of this study also suggest that temperature has significant effects on NPS nitrogen yield and that it caused the twin peaks in the temporal scale. Increasing the temperature above zero in April caused a temporal shift in soil water movement and transported nitrogen pollution earlier in the year, causing an increased loading in water before the summer irrigation, which is advantageous for NPS nitrogen pollution control.

  6. Metabolic engineering of oilseed crops to produce high levels of novel acetyl glyceride oils with reduced viscosity, freezing point and calorific value.

    PubMed

    Liu, Jinjie; Rice, Adam; McGlew, Kathleen; Shaw, Vincent; Park, Hyunwoo; Clemente, Tom; Pollard, Mike; Ohlrogge, John; Durrett, Timothy P

    2015-08-01

    Seed oils have proved recalcitrant to modification for the production of industrially useful lipids. Here, we demonstrate the successful metabolic engineering and subsequent field production of an oilseed crop with the highest accumulation of unusual oil achieved so far in transgenic plants. Previously, expression of the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene in wild-type Arabidopsis seeds resulted in the accumulation of 45 mol% of unusual 3-acetyl-1,2-diacyl-sn-glycerols (acetyl-TAGs) in the seed oil (Durrett et al., 2010 PNAS 107:9464). Expression of EaDAcT in dgat1 mutants compromised in their ability to synthesize regular triacylglycerols increased acetyl-TAGs to 65 mol%. Camelina and soybean transformed with the EaDAcT gene accumulate acetyl-triacylglycerols (acetyl-TAGs) at up to 70 mol% of seed oil. A similar strategy of coexpression of EaDAcT together with RNAi suppression of DGAT1 increased acetyl-TAG levels to up to 85 mol% in field-grown transgenic Camelina. Additionally, total moles of triacylglycerol (TAG) per seed increased 20%. Analysis of the acetyl-TAG fraction revealed a twofold reduction in very long chain fatty acids (VLCFA), consistent with their displacement from the sn-3 position by acetate. Seed germination remained high, and seedlings were able to metabolize the stored acetyl-TAGs as rapidly as regular triacylglycerols. Viscosity, freezing point and caloric content of the Camelina acetyl-TAG oils were reduced, enabling use of this oil in several nonfood and food applications. PMID:25756355

  7. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    ERIC Educational Resources Information Center

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  8. Preservation of flavor in freeze dried green beans

    NASA Technical Reports Server (NTRS)

    Huber, C. S.; Heidelbaugh, N. D.; Davis, D.

    1973-01-01

    Before freeze drying, green beans are heated to point at which their cell structure is altered. Beans freeze dried with altered cell structure have improved rehydration properties and retain color, flavor, and texture.

  9. Major depression

    MedlinePLUS

    Depression - major; Depression - clinical; Clinical depression; Unipolar depression; Major depressive disorder ... Ferri FF. Major depression. In: Ferri FF. Ferri's Clinical Advisor 2015 . Philadelphia, PA: Elsevier Mosby; 2015.

  10. Size-dependent freezing of n-alcohols in silicon nanochannels

    NASA Astrophysics Data System (ADS)

    Berwanger, R.; Schumacher, Ch.; Huber, P.; Pelster, R.

    2010-10-01

    We present a study on the phase behavior of several linear n-alcohols (heptanol, nonanol and undecanol) in their bulk state as well as confined in mesoporous silicon. We were able to vary the mean pore radii of the nanochannels from r = 3.5 nm to 7 nm and to determine the respective temperatures of the freezing and melting transitions using infrared and dielectric spectroscopy. The smaller the chain length the lower the freezing point, both in the bulk and in the confined state. Under confinement the freezing temperature decreases by up to 28 K compared to the bulk value. In accordance with the Gibbs-Thompson model the lowering is proportional to the inverse pore radius, ?Tfr ? 1/r. Moreover, the ratio of freezing temperature depression to melting temperature depression is close to the theoretical value of ?Tfr/?Tmelt = 3/2. The spectra also indicate a structural change: while the solid bulk alcohols are a polycrystalline mixture of the orthorhombic ?- and monoclinic ?-form, geometrical confinement forces the alcohol-chains into the more simple orthorhombic structure. In addition, a part of the material does not crystallize. Such an additional amorphous phase seems to be a logical consequence of the size mismatch between molecular crystals and irregular shaped pores.

  11. Molecular biology of freezing tolerance.

    PubMed

    Storey, Kenneth B; Storey, Janet M

    2013-07-01

    Winter survival for many kinds of animals involves freeze tolerance, the ability to endure the conversion of about 65% of total body water into extracellular ice and the consequences that freezing imposes including interruption of vital processes (e.g., heartbeat and breathing), cell shrinkage, elevated osmolality, anoxia/ischemia, and potential physical damage from ice. Freeze-tolerant animals include various terrestrially hibernating amphibians and reptiles, many species of insects, and numerous other invertebrates inhabiting both terrestrial and intertidal environments. Well-known strategies of freezing survival include accumulation of low molecular mass carbohydrate cryoprotectants (e.g., glycerol), use of ice nucleating agents/proteins for controlled triggering of ice growth and of antifreeze proteins that inhibit ice recrystallization, and good tolerance of anoxia and dehydration. The present article focuses on more recent advances in our knowledge of the genes and proteins that support freeze tolerance and the metabolic regulatory mechanisms involved. Important roles have been identified for aquaporins and transmembrane channels that move cryoprotectants, heat shock proteins and other chaperones, antioxidant defenses, and metabolic rate depression. Genome and proteome screening has revealed many new potential targets that respond to freezing, in particular implicating cytoskeleton remodeling as a necessary facet of low temperature and/or cell volume adaptation. Key regulatory mechanisms include reversible phosphorylation control of metabolic enzymes and microRNA control of gene transcript expression. These help to remodel metabolism to preserve core functions while suppressing energy expensive metabolic activities such as the cell cycle. All of these advances are providing a much more complete picture of life in the frozen state. PMID:23897687

  12. Freeze Prediction Model

    NASA Technical Reports Server (NTRS)

    Morrow, C. T. (principal investigator)

    1981-01-01

    Measurements of wind speed, net irradiation, and of air, soil, and dew point temperatures in an orchard at the Rock Springs Agricultural Research Center, as well as topographical and climatological data and a description of the major apple growing regions of Pennsylvania were supplied to the University of Florida for use in running the P-model, freeze prediction program. Results show that the P-model appears to have considerable applicability to conditions in Pennsylvania. Even though modifications may have to be made for use in the fruit growing regions, there are advantages for fruit growers with the model in its present form.

  13. Drought increases freezing tolerance of both leaves and xylem of Larrea tridentata.

    PubMed

    Medeiros, Juliana S; Pockman, William T

    2011-01-01

    Drought and freezing are both known to limit desert plant distributions, but the interaction of these stressors is poorly understood. Drought may increase freezing tolerance in leaves while decreasing it in the xylem, potentially creating a mismatch between water supply and demand. To test this hypothesis, we subjected Larrea tridentata juveniles grown in a greenhouse under well-watered or drought conditions to minimum temperatures ranging from -8 to -24 °C. We measured survival, leaf retention, gas exchange, cell death, freezing point depression and leaf-specific xylem hydraulic conductance (k?). Drought-exposed plants exhibited smaller decreases in gas exchange after exposure to -8 °C compared to well-watered plants. Drought also conferred a significant positive effect on leaf, xylem and whole-plant function following exposure to -15 °C; drought-exposed plants exhibited less cell death, greater leaf retention, higher k? and higher rates of gas exchange than well-watered plants. Both drought-exposed and well-watered plants experienced 100% mortality following exposure to -24 °C. By documenting the combined effects of drought and freezing stress, our data provide insight into the mechanisms determining plant survival and performance following freezing and the potential for shifts in L. tridentata abundance and range in the face of changing temperature and precipitation regimes. PMID:20825578

  14. Investigation of the Melting Point Depression of 12-Hydroxystearic Acid Organogels Using the Flory Diluent Model

    NASA Astrophysics Data System (ADS)

    Cavicchi, Kevin; Lipowski, Brian

    2013-03-01

    This talk will focus on the gelation behavior of 12-hydroxystearic acid (12-HSA) in organic solvents. Thermo-reversible gelation occurs by crystallization of 12-HSA in organic solvent to form 3-D fibrillar networks. The melting point vs. composition for 12-HSA in a range of solvents has been measured. The liquidus lines could be fit with the Flory-diluent model that takes into account the non-ideal free energy of mixing and the disparity in the size of the solvent and 12-HSA molecules. The fits indicated that the effective molar volume of 12-HSA increased as the hydrogen bonding Hansen solubility parameter ?h of the solvent decreased. This is attributed to the hydrogen-bonding driven aggregation of the 12-HSA in the liquid state based on previous observations that 12-HSA forms aggregated structures in non-polar solvents (e.g. dimers and tetrameters). These results indicate that the stabilization of the solid phase in 12-HSA solutions has contributions from both variations in the entropy of mixing as well the enthalpy of mixing. The importance of both these factors for designing small molecule gelators will be discussed.

  15. Influence of surface groups of proteins on water studied by freezing/thawing hysteresis and infrared spectroscopy.

    PubMed

    Zelent, Bogumil; Bryan, Michael A; Sharp, Kim A; Vanderkooi, Jane M

    2009-05-01

    The influence of proteins and solutes on hysteresis of freezing and melting of water was measured by infrared (IR) spectroscopy. Of the solutes examined, poly-L-arginine and flounder antifreeze protein produced the largest freezing point depression of water, with little effect on the melting temperature. Poly-L-lysine, poly-L-glutamate, cytochrome c and bovine serum albumin had less effect on the freezing of water. Small compounds used to mimic non-polar (trimethylamine N-oxide, methanol), positively charged (guanidinium chloride, NH(4)Cl, urea) and negatively charged (Na acetate) groups on protein surfaces were also examined. These molecules and ions depress water's freezing point and the melting profiles became broad. Since infrared absorption measures both bulk solvent and solvent bound to the solutes, this result is consistent with solutes interacting with liquid water. The amide I absorption bands of antifreeze protein and poly-L-arginine do not detectably change with the phase transition of water. An interpretation is that the antifreeze protein and poly-L-arginine order liquid water such that the water around the group is ice-like. PMID:19251353

  16. Fish antifreeze protein and the freezing and recrystallization of ice.

    PubMed

    Knight, C A; DeVries, A L; Oolman, L D

    Antifreeze glycopeptide and peptides from the blood of polar fishes prevent the growth of ice crystals in water at temperatures down to approximately 1 degree C below freezing point, but do not appreciably influence the equilibrium freezing point. This freezing point hysteresis must be a disequilibrium effect, or it would violate Gibbs' phase rule, but the separate freezing and melting points are experimentally very definite: ice neither melts nor freezes perceptibly within the 'hysteresis gap', for periods of hours or days. We report here unusual crystal faces on ice crystals grown from solutions of very low concentrations of the anti-freeze glycopeptides and peptides. This is a clue to the mechanism of freezing inhibition, and it may be the basis of a simple, very sensitive test for antifreeze material. Very low concentrations of the antifreeze protein are also remarkably effective in preventing the recrystallization of ice. PMID:6700733

  17. Freezing and Food Safety

    MedlinePLUS

    ... its quality. Rapid freezing prevents undesirable large ice crystals from forming throughout the product because the molecules ... sided snowflake. Slow freezing creates large, disruptive ice crystals. During thawing, they damage the cells and dissolve ...

  18. Insects that overwinter in regions where they are exposed to subzero temperatures must adapt by either becoming freeze

    E-print Network

    Barnes, Brian McRae

    by either becoming freeze tolerant (able to survive freezing of their body fluids) or freeze avoiding compared and, as expected, the supercooling points (the temperatures at which they froze) of these freeze Alaska C. clavipes did not freeze when cooled to ­80°C. Key words: beetle, insect, cold tolerance

  19. 3 CFR - Pay Freeze

    Code of Federal Regulations, 2010 CFR

    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... facing, I intend to freeze the salaries of senior members of the White House staff, to the...

  20. Validity of a portable urine refractometer: the effects of sample freezing.

    PubMed

    Sparks, S Andy; Close, Graeme L

    2013-01-01

    The use of portable urine osmometers is widespread, but no studies have assessed the validity of this measurement technique. Furthermore, it is unclear what effect freezing has on osmolality. One-hundred participants of mean (±SD) age 25.1 ± 7.6 years, height 1.77 ± 0.1 m and weight 77.1 ± 10.8 kg provided single urine samples that were analysed using freeze point depression (FPD) and refractometry (RI). Samples were then frozen at -80°C (n = 81) and thawed prior to re-analysis. Differences between methods and freezing were determined using Wilcoxon's signed rank test. Relationships between measurements were assessed using intraclass correlation coefficients (ICC) and typical error of estimate (TE). Osmolality was lower (P = 0.001) using RI (634.2 ± 339.8 mOsm · kgH2O(-1)) compared with FPD (656.7 ± 334.1 mOsm · kgH2O(-1)) but the TE was trivial (0.17). Freezing significantly reduced mean osmolality using FPD (656.7 ± 341.1 to 606.5 ± 333.4 mOsm · kgH2O(-1); P < 0.001), but samples were still highly related following freezing (ICC, r = 0.979, P < 0.001, CI = 0.993-0.997; TE = 0.15; and r=0.995, P < 0.001, CI = 0.967-0.986; TE = 0.07 for RI and FPD respectively). Despite mean differences between methods and as a result of freezing, such differences are physiologically trivial. Therefore, the use of RI appears to be a valid measurement tool to determine urine osmolality. PMID:23205563

  1. Study on the Realization of Indium Point

    NASA Astrophysics Data System (ADS)

    Widiatmo, Januarius V.; Yamazawa, Kazuaki; Satou, Kouichi; Tamba, Jun; Arai, Masaru

    Indium point cells are fabricated using ingots of various forms from a variety of sources (manufacturers). Using these cells, newly built indium point furnaces are evaluated and their reliability is confirmed. The indium point realizations based on the single solid-liquid method (SSL method) and multi solid-liquid method (MSL method) are evaluated. The effect of impurities in the ingots is evaluated from the dependency of the slope of the freezing curve on the change in furnace temperature, the indium point depression based on the impurity analysis, and the cell comparison. The results show equality among the cells. Based on the results obtained, the uncertainty in realizing the indium point using the described indium point cells and indium point furnaces is estimated. The new uncertainty budget introduces uncertainties coming from plateau repeatability and chemical impurity derived by the present work, the values of which are significantly lower than those adopted in the current calibration service.

  2. Influence of melt freezing characteristics on steam explosion energetics

    SciTech Connect

    Okkonen, T.; Sehgal, B.R.

    1996-08-01

    This paper examines the freezing process of distinct melt particles interacting with water. Approximate time scales of freezing are estimated for some high-temperature melt materials that are of interest in experimental and reactor situations. Transient conduction calculations are performed to clarify the special freezing characteristics of oxidic melt materials (low conductivity) and binary melt mixtures (no definite freezing point). The transient calculations are compared with recent experiments indicating ``non-explosivity`` of Corium (UO{sub 2}-ZrO{sub 2}). One potential explanation, based on the freezing characteristics of binary Corium mixture, is proposed for the experimental observations. The numerical results are generalized by discussing the scaling implications of the thermal conduction analysis and by defining different freezing categories. Finally, conclusions are drawn on the potential influence of melt freezing characteristics on steam explosion energetic.

  3. The Freezing Bomb

    ERIC Educational Resources Information Center

    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…

  4. Depression - resources

    MedlinePLUS

    Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good sources of information on depression : American Psychological Association - www.apa.org/topics/depress/ ...

  5. Freeze drying method

    SciTech Connect

    Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto

    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.

  6. Gravitino Freeze-In

    E-print Network

    Clifford Cheung; Gilly Elor; Lawrence Hall

    2011-03-22

    We explore an alternative mechanism for the production of gravitino dark matter whereby relic gravitinos originate from the decays of superpartners which are still in thermal equilibrium, i.e. via freeze-in. Contributions to the gravitino abundance from freeze-in can easily dominate over those from thermal scattering over a broad range of parameter space, e.g. when the scalar superpartners are heavy. Because the relic abundance from freeze-in is independent of the reheating temperature after inflation, collider measurements may be used to unambiguously reconstruct the freeze-in origin of gravitinos. In particular, if gravitino freeze-in indeed accounts for the present day dark matter abundance, then the lifetime of the next-to-lightest superpartner is uniquely fixed by the superpartner spectrum.

  7. Freeze drying apparatus

    DOEpatents

    Coppa, Nicholas V. (Malvern, PA); Stewart, Paul (Youngstown, NY); Renzi, Ernesto (Youngstown, NY)

    2001-01-01

    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.

  8. Freeze drying method

    SciTech Connect

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

    1999-12-07

    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.

  9. Freezing Fish and Shellfish. 

    E-print Network

    Nickelson, Ranzell; Reddell, Annette

    1980-01-01

    them home. Place ice in the belly cavity of each fish and provide adequate ice between and around fish. The ice chest should have a false bottom to allow for drainage of melting ice and eliminate the possibility of fish floating in bloody, dirty... at about - 20 degrees F ( - 28 degrees C). Rapid freezing is important. In the initial stage of a slow freezing process, small ice crystals form within the tissue cells. As the freezing continues the size of the ice crystals increases until...

  10. Hydrocarbon exclusion from ground water during freezing

    SciTech Connect

    Tumeo, M.A.; Davidson, B. )

    1993-08-01

    Bench-scale studies were conducted using a constant-head ground-water flow chamber and natural soil. Initial experiments with chlorides and dye were conducted to test the hydraulic and adsorptive characteristics of the chamber. A constant flow of phenol was then introduced into the chamber and contaminant movement with time was monitored under freezing and nonfreezing conditions. The chamber was located in a controlled-temperature room, and freezing fronts were induced from the soil surface downward using cooled Freon circulated through freezer pads placed on the surface of the soil. The results conclusively demonstrate that phenol is excluded from the freezing front and pushed downward through the system. Extensive exclusion of the chemical occurs even though the freezing point of phenol (43 C) is significantly higher than water. The information gained through this research is applicable in cold regions outside Alaska and the Arctic where ground water systems may undergo periodic freezing, and may also be of extreme importance in artificial-freezing scenarios such as those currently being investigated by the Environmental Protection Agency (EPA) as a method of contaminant containment.

  11. Improved freezing level retrieval 

    E-print Network

    Hong, Sungwook

    2002-01-01

    TRMM Microwave Imager(TMI)-based passive microwave retrieval techniques result in biased estimates of the freezing level and rainfall over the east Pacific in the Inter Tropical Convergence Zone (ITCZ). Passive microwave rainfall estimates...

  12. Future freeze forecasting

    NASA Technical Reports Server (NTRS)

    Bartholic, J. F.; Sutherland, R. A.

    1979-01-01

    Real time GOES thermal data acquisition, an energy balance minimum temperature prediction model and a statistical model are incorporated into a minicomputer system. These components make up the operational "Satellite Freeze Forecast System" being used to aid NOAA, NWS forecasters in developing their freeze forecasts. The general concept of the system is presented in this paper. Specific detailed aspects of the system can be found in the reference cited.

  13. Freezing Cellular Automata Bootstrap Percolation

    E-print Network

    Theyssier, Guillaume

    Freezing Cellular Automata and Bootstrap Percolation UAI - Doctorado en Ingenería de Sistemas-nilpotency is a simpler problem (0 2) in the simply convergent case #12;#12;Freezing cellular automata #12;Freezing cellular automata Q = {0, . . . , n - 1} with natural order N arbitrary neighborhood F is freezing if x, z

  14. Two-dimensional freezing criteria for crystallizing colloidal monolayers

    SciTech Connect

    Wang Ziren; Han Yilong; Alsayed, Ahmed M.

    2010-04-21

    Video microscopy was employed to explore crystallization of colloidal monolayers composed of diameter-tunable microgel spheres. Two-dimensional (2D) colloidal liquids were frozen homogenously into polycrystalline solids, and four 2D criteria for freezing were experimentally tested in thermal systems for the first time: the Hansen-Verlet freezing rule, the Loewen-Palberg-Simon dynamical freezing criterion, and two other rules based, respectively, on the split shoulder of the radial distribution function and on the distribution of the shape factor of Voronoi polygons. Importantly, these freezing criteria, usually applied in the context of single crystals, were demonstrated to apply to the formation of polycrystalline solids. At the freezing point, we also observed a peak in the fluctuations of the orientational order parameter and a percolation transition associated with caged particles. Speculation about these percolated clusters of caged particles casts light on solidification mechanisms and dynamic heterogeneity in freezing.

  15. H, not O or pressure, causes eutectic T depression in the Fe-FeS System to 8 GPa

    NASA Astrophysics Data System (ADS)

    Buono, Antonio S.; Walker, David

    2015-04-01

    The Fe-FeS system maintains a eutectic temperature of 990 ± 10 °C to at least 8 GPa if starting materials and pressure media are rigorously dehydrated. Literature reports of pressure-induced freezing point depression of the eutectic for the Fe-FeS system are not confirmed. Modest addition of oxygen alone is confirmed to cause negligible freezing point depression at 6 GPa. Addition of H alone causes a progressive decrease in the eutectic temperature with P in the Fe-FeS-H system to below 965 °C at 6 GPa to below 950 °C at 8 GPa. It is our hypothesis that moisture contamination in unrigorously dried experiments may be an H source for freezing point depression. O released from H2O disproportionation reacts with Fe and is sequestered as ferropericlase along the sample capsules walls, leaving the H to escape the system and/or enter the Fe-FeS mixture. The observed occurrence of ferropericlase on undried MgO capsule margins is otherwise difficult to explain, because an alternate source for the oxygen in the ferropericlase layer is difficult to identify. This study questions the use of pressure-depressed Fe-S eutectic temperatures and suggests that the lower eutectic temperatures sometimes reported are achieved by moving into the ternary Fe-S-H system. These results adjust slightly the constraints on eutectic temperatures allowed for partly solidified cores on small planets. H substantially diminishes the temperature extent of the melting interval in Fe-S by reducing the melting points of the crystalline phases more than it depresses the eutectic.

  16. Freezing and melting water in lamellar structures.

    PubMed

    Gleeson, J T; Erramilli, S; Gruner, S M

    1994-08-01

    The manner in which ice forms in lamellar suspensions of dielaidoylphosphatidylethanolamine, dielaidoylphosphatidylcholine, and dioleoylphosphatidylcholine in water depends strongly on the water fraction. For weight fractions between 15 and 9%, the freezing and melting temperatures are significantly depressed below 0 degree C. The ice exhibits a continuous melting transition spanning as much as 20 degrees C. When the water weight fraction is below 9%, ice never forms at temperatures as low as -40 degrees C. We show that when water contained in a lamellar lipid suspension freezes, the ice is not found between the bilayers; it exists as pools of crystalline ice in equilibrium with the bound water associated with the polar lipid headgroups. We have used this effect, together with the known chemical potential of ice, to measure hydration forces between lipid bilayers. We find exponentially decaying hydration repulsion when the bilayers are less than about 7 A apart. For larger separations, we find significant deviations from single exponential decay. PMID:7948683

  17. High-freezing-point fuel studies

    NASA Technical Reports Server (NTRS)

    Tolle, F. F.

    1980-01-01

    Considerable progress in developing the experimental and analytical techniques needed to design airplanes to accommodate fuels with less stringent low temperature specifications is reported. A computer technique for calculating fuel temperature profiles in full tanks was developed. The computer program is being extended to include the case of partially empty tanks. Ultimately, the completed package is to be incorporated into an aircraft fuel tank thermal analyser code to permit the designer to fly various thermal exposure patterns, study fuel temperatures versus time, and determine holdup.

  18. A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant

    E-print Network

    Barnes, Brian McRae

    A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan between the melting and freezing points of a solution that is indicative of the presence of large) have not yet been structur- ally characterized, and none have been characterized from a freeze

  19. Bjorken model with Freeze Out

    E-print Network

    V. K. Magas; L. P. Csernai

    2007-11-19

    The freeze out of the expanding systems, created in relativistic heavy ion collisions, is discussed. We combine Bjorken scenario with earlier developed freeze out equations into a unified model. The important feature of the proposed model is that physical freeze out is completely finished in a finite time, which can be varied from 0 (freeze out hypersurface) to infinity. The dependence of the post freeze out distribution function on this freeze out time will be studied. As an example model is completely solved and analyzed for the gas of pions.

  20. Avoidance and tolerance of freezing in ectothermic vertebrates.

    PubMed

    Costanzo, Jon P; Lee, Richard E

    2013-06-01

    Ectothermic vertebrates have colonized regions that are seasonally or perpetually cold, and some species, particularly terrestrial hibernators, must cope with temperatures that fall substantially below 0°C. Survival of such excursions depends on either freeze avoidance through supercooling or freeze tolerance. Supercooling, a metastable state in which body fluids remain liquid below the equilibrium freezing/melting point, is promoted by physiological responses that protect against chilling injury and by anatomical and behavioral traits that limit risk of inoculative freezing by environmental ice and ice-nucleating agents. Freeze tolerance evolved from responses to fundamental stresses to permit survival of the freezing of a substantial amount of body water under thermal and temporal conditions of ecological relevance. Survival of freezing is promoted by a complex suite of molecular, biochemical and physiological responses that limit cell death from excessive shrinkage, damage to macromolecules and membranes, metabolic perturbation and oxidative stress. Although freeze avoidance and freeze tolerance generally are mutually exclusive strategies, a few species can switch between them, the mode used in a particular instance of chilling depending on prevailing physiological and environmental conditions. PMID:23678097

  1. Freezing of Lennard-Jones-type fluids

    SciTech Connect

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

    2011-02-07

    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.

  2. Freezing Poultry for Home Use 

    E-print Network

    Davis, Michael

    2006-08-31

    Purchasing fresh poultry in large packages and freezing it in quantities suitable for individual meals can stretch time and food dollars. Topics include packaging needs, cutting, storing and thawing instructions, and freezing pre-cooked meals....

  3. Freeze Branding Horses 

    E-print Network

    Householder, Doug; Webb, Gary; Wigington, Sam; Bruemmer, Jason

    2001-06-29

    Freeze branding of horses has many advantages. It is safe, economical, simple to do and relatively painless. It can be done on horses of any age and does not damage the horse's hide. This publication gives complete, step-by-step instructions...

  4. Freezing and thawing processes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seasonally frozen soil strongly influences runoff and erosion on large areas of land around the world. In many areas, rain or snowmelt on seasonally frozen soil is the single leading cause of severe runoff and erosion events. As soils freeze, ice blocks the soil pores, greatly diminishing the permea...

  5. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 3 2010-01-01 2010-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  6. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 2011-01-01 2011-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  7. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 3 2012-01-01 2012-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  8. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 3 2013-01-01 2013-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  9. Freezing Spring Temperatures Damage Knobcone Pine

    E-print Network

    Freezing Spring Temperatures Damage Knobcone Pine Stanley L. Krugman U. S. FOREST SERVICE RESEARCH, Stanley L. 1966. Freezing spring temperatures damage knobcone pine conelets. Berkeley, Calif.. Pacific pine, conelets, freezing temperature) Krugman, Stanley L. 1966. Freezing spring temperatures damage

  10. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 3 2014-01-01 2014-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  11. SURROGATE BRIDGE FREEZING SRDJAN JANKOVIC

    E-print Network

    SURROGATE BRIDGE FREEZING SENSORS by SRDJAN JANKOVIC Bachelor of Science University of Belgrade: Stillwater, Oklahoma Title of Study: SURROGATE BRIDGE FREEZING SENSORS Pages in Study: 121 Candidate of this study was to design and test surrogate bridge freezing sensors in order to provide training data

  12. Study on the Realization of Zinc Point and the Zinc-Point Cell Comparison

    NASA Astrophysics Data System (ADS)

    Widiatmo, J. V.; Sakai, M.; Satou, K.; Yamazawa, K.; Tamba, J.; Arai, M.

    2011-01-01

    Continuing our study on aluminum, tin, and silver points, a study on the realization of the zinc point was conducted. Zinc-point cells were newly fabricated using 6N-nominal grade zinc samples, impurity elements of which were analyzed extensively based on glow-discharge mass spectrometry (GDMS). The present paper reports the temperature measurements done using the newly fabricated cells during the zinc freezing process, under which the zinc fixed point is defined, and the analysis of the freezing curve obtained. Comparisons of zinc-point temperatures realized by the newly fabricated cells (cell-to-cell comparisons) were also conducted. Zinc-point depression due to impurity elements was calculated based on the sum of individual estimates and the impurity element analysis. One of the cells evaluated was drawn out from its crucible and analyzed by GDMS at four points, namely, at around the center of the top, of the middle, of the bottom, and around the outer part of the middle area. The purpose of this cell disassembly is to see whether or not there has been some difference before and after cell fabrication, as well as difference in impurity element distribution within the ingot. From the aforementioned studies, some findings were obtained. First finding is that the homogeneity of the zinc ingot was within 30%, except for Pb, which was more concentrated in the center part. Second finding is that the cell-to-cell temperature difference changes along with the progressing solidification process. As a consequence, for an accurate cell-to-cell comparison, the locus in the freezing plateau where the comparison is done should be determined. Third finding is that the slope analysis estimates accurately the cell-to-cell comparison, and is consistent with the impurity analysis. This shows that the slope analysis gives extensive information about the effect of impurity to the zinc-point realization, especially after the cell fabrication.

  13. On estimating freezing times during tissue rapid freezing.

    PubMed

    Jones, G J

    1984-12-01

    For the study of morphological changes that are associated with fast physiological processes, it is important to know the times at which the surface regions of specimens are frozen during rapid freezing. A simple physical model has been used to estimate the freezing times and the cooling rates at 10 micron depths in specimens. The calculations indicate that cooling rates in excess of 4 X 10(4) K s-1 are associated with freezing times of less than 0.5 ms. Using the same model, experimental measurements of freezing times at much larger depths have been extrapolated to a depth of 10 micron, the times obtained are 0.1-0.6 ms for freezing by rapid immersion in cryogenic liquids, and 0.1 ms or less for freezing on a metal block. It is concluded that the delay time between contact with a cryogenic source and specimen freezing is less than 0.5 ms. The uncertainty in the time of freezing may be larger than this, because of an uncertainty of about +/- 0.5 ms in determining the exact time of contact and, for freeze fracture studies, because of an uncertainty of up to 0.5 ms due to imprecision in the depth of fracture. At the same time it is estimated that the time during which freezing takes place may be as high as 250 microseconds, which can be taken as an upper limit for the resolution time for rapid freezing. PMID:6520865

  14. Teen Depression

    MedlinePLUS

    ... you are going through. Depression is not your fault or caused by something you did wrong Depression ... being negative. Remember that depression is not your fault! Learn more National Institute of Mental Health (NIMH): ...

  15. Postpartum depression

    MedlinePLUS

    Depression - postpartum; Postnatal depression; Postpartum psychological reactions ... The exact causes of postpartum depression are unknown. Changes in hormone levels during and after pregnancy may affect a woman’s mood. Many non-hormonal factors may also ...

  16. Postpartum Depression

    MedlinePLUS

    ... QUESTIONS FAQ091 LABOR, DELIVERY, AND POSTPARTUM CARE Postpartum Depression • What are the postpartum blues? • How long do the postpartum blues usually last? • What is postpartum depression? • When does postpartum depression occur? • What causes postpartum ...

  17. Postpartum Depression

    MedlinePLUS

    ... all forms of depression, postpartum depression creates a cloud of negative feelings and thoughts over a woman's ... her, her situation, and the future. Under the cloud of depression, a woman might see herself as ...

  18. Seasonal accumulation of acetylated triacylglycerols by a freeze-tolerant insect.

    PubMed

    Marshall, Katie E; Thomas, Raymond H; Roxin, Aron; Chen, Eric K Y; Brown, Jason C L; Gillies, Elizabeth R; Sinclair, Brent J

    2014-05-01

    Most animals store energy as long-chain triacylglycerols (lcTAGs). Trace amounts of acetylated triacylglycerols (acTAGs) have been reported in animals, but are not accumulated, likely because they have lower energy density than lcTAGs. Here we report that acTAGs comprise 36% of the neutral lipid pool of overwintering prepupae of the goldenrod gall fly, Eurosta solidaginis, while only 17% of the neutral lipid pool is made up of typical lcTAGs. These high concentrations of acTAGs, present only during winter, appear to be synthesized by E. solidaginis and are not found in other freeze-tolerant insects, nor in the plant host. The mixture of acTAGs found in E. solidaginis has a significantly lower melting point than equivalent lcTAGs, and thus remains liquid at temperatures at which E. solidaginis is frozen in the field, and depresses the melting point of aqueous solutions in a manner unusual for neutral lipids. We note that accumulation of acTAGs coincides with preparation for overwintering and the seasonal acquisition of freeze tolerance. This is the first observation of accumulation of acTAGs by an animal, and the first evidence of dynamic interconversion between acTAGs and lcTAGs during development and in response to stress. PMID:24790101

  19. Double freezing of (NH(4))(2)SO(4)/H(2)O droplets below the eutectic point and the crystallization of (NH(4))(2)SO(4) to the ferroelectric phase.

    PubMed

    Bogdan, A

    2010-09-23

    This paper presents the differential scanning calorimetry (DSC) results obtained from measurements of single droplets of different subeutectic concentrations (<40 wt % (NH4)2SO4) and diameters of 1-1.5 mm. The measurements show that despite the fact that the freezing of the droplets takes place below the eutectic temperature of Te ? 254.5 K, a phase separation into ice and a residual freeze-concentrated solution occurs. The residual solution is formed by the expulsion of NH4+ and SO42- ions from the ice lattice during the nucleation and growth of ice and may possess the eutectic concentration of 40 wt % (NH4)2SO4. On further cooling, the residual solution freezes to the eutectic solid mixture of ice/(NH4)2SO4 at a temperature that is either above or below the ferroelectric "Curie" temperature of Tc ? 223 K. If the freezing of the residual solution takes place below the Tc, then (NH4)2SO4 crystallizes directly into the ferroelectric phase. PMID:20735056

  20. Experimental investigation of molten metal freezing on to a structure

    SciTech Connect

    Mizanur Rahman, M.; Hino, Tomohiko; Morita, Koji; Matsumoto, Tatsuya; Nakagawa, Kiyoshi; Fukuda, Kenji; Maschek, Werner

    2007-10-15

    During core disruptive accidents (CDAs) of Liquid Metal Reactors (LMRs), it is important to understand the freezing phenomena of molten metal, which may prevent fuel dispersal and subsequent shutdown. The present paper describes the freezing behavior of molten metal during interaction with a structure with a view to the safety of LMRs. In this study, Wood's metal (melting point 78.8 C) was used as a simulant melt, while stainless steel and copper were used as freezing structures. A series of simulation experiments was conducted to study the freezing behavior of Wood's metal during pouring on to the freezing structures immersed in a coolant. In the experiments, simulant melt was poured into a stainless steel tube and finally ejected into a coolant through a nozzle so as to observe the freezing behavior of the molten metal. The penetration length and width were measured in the air cooled experiments, whereas penetration length and the proportion of adhering frozen metal were measured in water coolant experiment. The melt flow and distribution were observed in both types of experiment using a high-speed video camera. Distinct freezing modes were observed in the water coolant experiments, whereas only one freezing mode with a longer melt penetration was found in air coolant experiments. The present result will be utilized to create a relevant database for the verification of reactor safety analysis codes. (author)

  1. THE EFFECT OF FROST/FREEZE EVENTS ON MOPANE TREES Prepared by Melissa Whitecross, Honours student, at the University of the Witwatersrand

    E-print Network

    THE EFFECT OF FROST/FREEZE EVENTS ON MOPANE TREES Prepared by Melissa Whitecross, Honours student that Colophospermum mopane (Mopane Tree) is affected by frost/freeze events and this could be related to the unique in temperatures falling below the freezing point (0°C). A freeze event, however, describes a severe cooling event

  2. Freeze out of the expanding system

    E-print Network

    V. K. Magas; L. P. Csernai; E. Molnar

    2007-02-22

    The freeze out (FO) of the expanding systems, created in relativistic heavy ion collisions, is discussed. We start with kinetic FO model, which realizes complete physical FO in a layer of given thickness, and then combine our gradual FO equations with Bjorken type system expansion into a unified model. We shall see that the basic FO features, pointed out in the earlier works, are not smeared out by the expansion.

  3. The Theory of Ice Nucleation by Heterogeneous Freezing of Deliquescent Mixed CCN. Part I: Critical Radius, Energy, and Nucleation Rate.

    NASA Astrophysics Data System (ADS)

    Khvorostyanov, Vitaly I.; Curry, Judith A.

    2004-11-01

    This paper extends previous work on the theory of heterogenous ice nucleation. The goals of this analysis are to explain empirical observations of ice nucleation and to provide a suitable framework for modeling and parameterizing the ice nucleation process in cloud-scale and large-scale atmospheric models. Considered are the processes of heterogeneous freezing of deliquescent mixed cloud condensation nuclei that may serve as ice nuclei, and the properties of an ice germ critical radius, energy, and nucleation rate of ice crystals are examined as functions of temperature and supersaturation. Expressions for nucleation in a polydisperse aerosol for the deliquescence-freezing mode are developed. Equations are derived for the threshold and critical saturation ratios as functions of temperature and nucleation rate, and for the threshold and critical temperatures as functions of saturation ratio. Equivalence of the new formulation for the freezing point depression with traditional expressions is shown and the concepts of the effective temperature and supercooling are introduced. These new formulations are used in a companion paper for simulations of ice nucleation using a cloud parcel model.


  4. [Severe depression : psychoanalysis].

    PubMed

    Bouvet de la Maisonneuve, O

    2009-12-01

    The indication for psychoanalysis in severe depression is not clear. And yet, demands for this type of intervention are increasing, despite the absence of any form of consensus on the subject. Freud considered depression as a failure of analytical efforts and, based on this observation, revised his theory, in particular to include the notions of narcissism and the death drive. Many analysts have been reluctant to follow his teachings on this last point and provide depressed patients with analytical-type therapies aimed at restoring narcissism. Melanie Klein pushed Freud's ideas about depression even further and brought such therapies back to the heart of analytical practice. Jacques Lacan took the debate to another level by proposing an overhaul of the principles on which analysis has been based. Today, while following certain precautionary rules, true psychoanalyses can be proposed to patients with severe depression, whether of the bipolar, recurring or even neurotic type that can reach this level of severity. PMID:20141799

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

    PubMed Central

    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.

  6. Freeze-Tolerant Condensers

    NASA Technical Reports Server (NTRS)

    Crowley, Christopher J.; Elkouhk, Nabil

    2004-01-01

    Two condensers designed for use in dissipating heat carried by working fluids feature two-phase, self-adjusting configurations such that their working lengths automatically vary to suit their input power levels and/or heat-sink temperatures. A key advantage of these condensers is that they can function even if the temperatures of their heat sinks fall below the freezing temperatures of their working fluids and the fluids freeze. The condensers can even be restarted from the frozen condition. The top part of the figure depicts the layout of the first condenser. A two-phase (liquid and vapor) condenser/vapor tube is thermally connected to a heat sink typically, a radiatively or convectively cooled metal panel. A single-phase (liquid) condensate-return tube (return artery) is also thermally connected to the heat sink. At intervals along their lengths, the condenser/vapor tube and the return artery are interconnected through porous plugs. This condenser configuration affords tolerance of freezing, variable effective thermal conductance (such that the return temperature remains nearly constant, independently of the ultimate sink temperature), and overall pressure drop smaller than it would be without the porous interconnections. An additional benefit of this configuration is that the condenser can be made to recover from the completely frozen condition either without using heaters, or else with the help of heaters much smaller than would otherwise be needed. The second condenser affords the same advantages and is based on a similar principle, but it has a different configuration that affords improved flow of working fluid, simplified construction, reduced weight, and faster recovery from a frozen condition.

  7. Role of Heart and its Diseases in the Etiology of Depression According to Avicenna's Point of View and its Comparison with Views of Classic Medicine

    PubMed Central

    Yousofpour, Mohammad; Kamalinejad, Mohammad; Esfahani, Mohammad Mahdi; Shams, Jamal; Tehrani, Hassan Hoshdar; Bahrami, Mohsen

    2015-01-01

    Background: Depression is one of the most important medical problems in today's world; despite its high prevalence, its causes unfortunately remain not fully known. Among important issues regarding this is its relation with heart diseases. Based on studies this comorbidity increase morbidity and mortality and leads to worst prognosis. However the cause of such high rate of comorbidity is unclear and instead of efforts to understand this correlation has prompted the medical world to consult other medicinal disciplines, not only to find the answer but also to increase the effectiveness of treatment and decrease its cost. Methods: We first reviewed the most important ancient causes for depression mentioned by Avicenna and considered those as the key words for our next step. Then, we made a literature search (PubMed and Scopus) with those key words to find out new scientific findings in modern medicine about the Avicenna's suggestions. Results: Avicenna does not regard depression as only a mental ailment, but as a disorder resulted by the involvement of brain, heart and blood. He believed that the main causes of depressive events are rooted in heart diseases; in most cases brain is only affected secondary to the heart. Thus he declared that for the treatment of depressive disorders, the underlying cardiovascular diseases should be considered. Conclusions: It is worthwhile to consider the Avicenna's recommended causes of depression and to design future scientific studies based on his suggestions. PMID:26124946

  8. Performance Characteristics of an Isothermal Freeze Valve

    SciTech Connect

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  9. Prevention of freezing in measuring and regulating equipment

    SciTech Connect

    Wofford, D.

    1995-12-01

    The strict and competitive business environment in which the natural gas industry operates today dictates that measurement and control systems which are utilized are of the highest achievable operational integrity. This entails not only that measurements and controls are performed and maintained precisely and reliably, but also that consideration is given to operational phenomena which may adversely affect the overall performance and integrity of such systems. Freezing is an operational occurrence winch frequently affects the functionality and performance of measurement and regulating systems. Freezing is the result of either ice or hydrate formation within the gas stream and is dependent upon the presence of water. Ice forms in the system when the water vapor within the gas stream experiences such conditions that condensation and freezing occurs. Ice will form at approximately 320 Fahrenheit Hydrates form in the system when water vapor within the gas stream combines with hydrocarbons and forms a compound which will condense and freeze at temperatures winch are often above the freezing point for water alone. Hydrate formations usually occur in gathering lines which are saturated with water vapor. In either case, the freezing condition can result in measurement errors, regulating and control equipment malfunction, and complete line blockages. These results ultimately have detrimental economic and operational impact. Therefore, the avoidance of freezing problems is a good long term investment.

  10. Combined impacts of freeze-thaw processes on paddy land and dry land in Northeast China.

    PubMed

    Chen, Siyang; Ouyang, Wei; Hao, Fanghua; Zhao, Xuchen

    2013-07-01

    The quantity of spring snowmelt infiltration and runoff, which affects the hydrology of the freeze zone, depends on the antecedent soil water content (SWC) conditions at the time of the soil's freezing. An understanding of the characteristics of frozen soil is essential for spring sowing in the agricultural freeze zones. The main goal of this study was to evaluate the differences in the freeze-thaw process and the freeze-thaw-induced water redistribution between the paddy and dry lands in a freeze zone. For this purpose, a field study was conducted in the winter of 2011-2012 for two types of farmlands in Northeast China. To illustrate the soil's frost dynamics over time, the measured SWCs at different depths (15, 30, 60, and 90 cm) were transformed into different expressions including the SWC dynamic, the frozen soil's profile, and the freezing and thawing front trace. The freezing characteristics in the paddy land, in contrast to that in the dry land, had a higher freezing point temperature, a larger amount of water movement to the upper layer, and a 2.76 mm larger accumulation of water in the upper layer. However, the increase of SWC (which is equivalent to thawing) was evidently faster than the decrease of SWC (which is equivalent to freezing). The water in the frozen soil's profile was most likely redistributed towards the freezing front before soil temperature (ST) falls below the freezing point. The findings may partially explain the soil's freeze-thaw characteristics for the different stages as well as the combined impact of these characteristics with farmland use types on soil hydrology; the findings may also provide a foundation for forecasting the hydrologic response of the freeze-thaw process and provide guidance for management strategies dealing with seasonally frozen agricultural soils. PMID:23584030

  11. Freezing in Sealed Capillaries for Preparation of Frozen Hydrated Sections

    PubMed Central

    Yakovlev, Sergey; Downing, Kenneth H.

    2014-01-01

    We have investigated the freezing of specimens in a confined volume for preparation of vitreous samples for cryosectioning. With 15% dextran as a cryoprotectant, a sample sealed in a copper tube begins to freeze into crystalline ice when plunged into liquid ethane. Crystallization rapidly causes an increase in the pressure to the point that much of the sample freezes in a vitreous state. We used synchrotron X-ray diffraction of samples frozen with various amounts of dextran to characterize the ice phases and crystal orientation, providing insights on the freezing process. We have characterized cryosections obtained from these samples to explore the optimum amount of cryoprotectant. Images of cryosectioned bacteria frozen with various levels of cryoprotectant illustrate effects of cryoprotectant concentration. PMID:22077543

  12. Postpartum Depression

    MedlinePLUS

    ... do not need treatment. The symptoms of postpartum depression last longer and are more severe. You may ... treatment right away, often in the hospital. Postpartum depression can begin anytime within the first year after ...

  13. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2 2012-01-01 2012-01-01 false Freezing facilities. 590.534 Section 590.534...Processing, and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises,...

  14. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2 2014-01-01 2014-01-01 false Freezing facilities. 590.534 Section 590.534...Processing, and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises,...

  15. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2 2010-01-01 2010-01-01 false Freezing facilities. 590.534 Section 590.534...Processing, and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises,...

  16. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2 2011-01-01 2011-01-01 false Freezing facilities. 590.534 Section 590.534...Processing, and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises,...

  17. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2 2013-01-01 2013-01-01 false Freezing facilities. 590.534 Section 590.534...Processing, and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises,...

  18. Freezing of living cells

    SciTech Connect

    Mazur, P.

    1985-01-01

    It can be calculated that a living cell will survive more than 5000 years at -196/sup 0/C. This ability to essentially stop biological time has important implications in medicine and agriculture, and in biological research. In medicine the chief implications are in the banking of transplantable tissues and organs and in in vitro fertilization. In agriculture the applications stem in part from the role of frozen embryos in amplifying the number of calves produced by high quanlity cows. The problem is how can cells survive both the cooling to such very low temperatures and the return to normal temperatures. The answers involve fundamental characteristics of cells such as the permeability of their surface membranes to water and solutes. These characteristics determine whether or not cells undergo lethal internal ice formation and other response during freezing and thawing. 27 refs., 12 figs.

  19. Understanding Slag Freeze Linings

    NASA Astrophysics Data System (ADS)

    Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni

    2014-09-01

    Slag freeze linings, the formation of protective deposit layers on the inner walls of furnaces and reactors, are increasingly used in industrial pyrometallurgical processes to ensure that furnace integrity is maintained in these aggressive, high-temperature environments. Most previous studies of freeze-linings have analyzed the formation of slag deposits based solely on heat transfer considerations. These thermal models have assumed that the interface between the stationary frozen layer and the agitated molten bath at steady-state deposit thickness consists of the primary phase, which stays in contact with the bulk liquid at the liquidus temperature. Recent experimental studies, however, have clearly demonstrated that the temperature of the deposit/liquid bath interface can be lower than the liquidus temperature of the bulk liquid. A conceptual framework has been proposed to explain the observations and the factors influencing the microstructure and the temperature of the interface at steady-state conditions. The observations are consistent with a dynamic steady state that is a balance between (I) the rate of nucleation and growth of solids on detached crystals in a subliquidus layer as this fluid material moves toward the stagnant deposit interface and (II) the dissolution of these detached crystals as they are transported away from the interface by turbulent eddies. It is argued that the assumption that the interface temperature is the liquidus of the bulk material represents only a limiting condition, and that the interface temperature can be between T liquidus and T solidus depending on the process conditions and bath chemistry. These findings have implications for the modeling approach and boundary conditions required to accurately describe these systems. They also indicate the opportunity to integrate considerations of heat and mass flows with the selection of melt chemistries in the design of future high temperature industrial reactors.

  20. Adolescent Depression.

    ERIC Educational Resources Information Center

    Evans, Dina M.

    Affective disorder is characterized by maladaptive changes in mood, attitudes, energy level, and physical status. These changes constitute the basic dimensions of depression. Depression results from a combination of genetic and experiential factors. There are sex differences and age differences with regard to depression, and there is a high…

  1. Thermal freeze-out versus chemical freeze-out reexamined

    E-print Network

    Dariusz Prorok

    2010-03-04

    An alternative, to the commonly used blast-wave, model describing the freeze-out hypersurface is applied to fit the $p_{T}$-spectra of identified hadrons measured at relativistic heavy-ion collisions at $\\sqrt{s_{NN}}=62.4, 130$ and 200 GeV. Decays of resonances are taken into account completely. It has turned out that the fitted freeze-out temperature and baryon number chemical potential depend weakly on the centrality of the collision and their values are close to the chemical freeze-out values determined from fits to particle yield ratios.

  2. Benchmarking numerical freeze/thaw models

    NASA Astrophysics Data System (ADS)

    Rühaak, Wolfram; Anbergen, Hauke; Molson, John; Grenier, Christophe; Sass, Ingo

    2015-04-01

    The modeling of freezing and thawing of water in porous media is of increasing interest, and for which very different application areas exist. For instance, the modeling of permafrost regression with respect to climate change issues is one area, while others include geotechnical applications in tunneling and for borehole heat exchangers which operate at temperatures below the freezing point. The modeling of these processes requires the solution of a coupled non-linear system of partial differential equations for flow and heat transport in space and time. Different code implementations have been developed in the past. Analytical solutions exist only for simple cases. Consequently, an interest has arisen in benchmarking different codes with analytical solutions, experiments and purely numerical results, similar to the long-standing DECOVALEX and the more recent "Geothermal Code Comparison" activities. The name for this freezing/ thawing benchmark consortium is INTERFROST. In addition to the well-known so-called Lunardini solution for a 1D case (case T1), two different 2D problems will be presented, one which represents melting of a frozen inclusion (case TH2) and another which represents the growth or thaw of permafrost around a talik (case TH3). These talik regions are important for controlling groundwater movement within a mainly frozen ground. First results of the different benchmark results will be shown and discussed.

  3. Commercial Application of Freeze Crystallization 

    E-print Network

    Gorgol, R. G.

    1992-01-01

    the world bcgan. The most noticeable frozen substance is, of course, water. Snow, ice cubcs, frozen lakes and streams, even iccbcrgs are all evidences of the freezing process at work. This process is also used to form crystalline compounds in industry... understand the water they obtained from ice was potable. RECENT APPLICATIONS Scientists have understood the basic mechanism of the freezing phase change for many years. ID an effort to harness the power of this phenomena, applications were researched...

  4. RESEARCH ARTICLE Cryoprotectants and Extreme Freeze

    E-print Network

    Lee Jr., Richard E.

    RESEARCH ARTICLE Cryoprotectants and Extreme Freeze Tolerance in a Subarctic Population of the Wood in freeze tolerance, with sub- arctic populations tolerating experimental freezing to temperatures at least investigated their physiological responses to somatic freezing at extreme temperatures. Alaskan frogs collected

  5. Introducing freezing cellular automata Taller @ Concepcin

    E-print Network

    Theyssier, Guillaume

    Introducing freezing cellular automata Taller @ Concepción G. Theyssier (CNRS, CMM) October, 2013;#12;Freezing cellular automata Q = {0, . . . , n - 1} with natural order N arbitrary neighborhood F is freezing if x, z : F(x)z xz #12;Freezing cellular automata Q = {0, . . . , n - 1} with natural order N

  6. A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials

    SciTech Connect

    Reis, A.; Duarte, J. F.; Santos, A. D.; Magalhaes, A. B.; Houbaert, Y.

    2007-05-17

    The aim of the model presented in this paper is to capture the difference in solidification behaviour of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based 3-D feeding flow model has been developed to evaluate shrinkage defects for casting alloys. A continuum formulation is used to describe the transport of mass, energy and momentum. It is assumed that during solidification the driving force for flow is shrinkage. A Darcy type source term has been included in the momentum equation to account for flow resistance in the mushy zone. A VOF free surface model has been used to describe shrinkage defects, i.e., external surface depressions and internal shrinkage porosities, while ensuring mass conservation. The model is used to calculate the shrinkage in a simple casting. The results shows internal and outside shrinkage defects depending on the freezing range of the metal. Short freezing range results mainly in internal shrinkage whereas the long freezing range results in external shrinkage. The expected shrinkage features are well described by the present model.

  7. Hepatitis B vaccine freezing in the Indonesian cold chain: evidence and solutions.

    PubMed Central

    Nelson, Carib M.; Wibisono, Hariadi; Purwanto, Hary; Mansyur, Isa; Moniaga, Vanda; Widjaya, Anton

    2004-01-01

    OBJECTIVES: To document and characterize freezing temperatures in the Indonesian vaccine cold chain and to evaluate the feasibility of changes designed to reduce the occurrence of freezing. METHODS: Data loggers were used to measure temperatures of shipments of hepatitis B vaccine from manufacturer to point of use. Baseline conditions and three intervention phases were monitored. During each of the intervention phases, vaccines were removed progressively from the standard 2-8 degrees C cold chain. FINDINGS: Freezing temperatures were recorded in 75% of baseline shipments. The highest rates of freezing occurred during transport from province to district, storage in district-level ice-lined refrigerators, and storage in refrigerators in health centres. Interventions reduced freezing, without excessive heat exposure. CONCLUSIONS: Inadvertent freezing of freeze-sensitive vaccines is widespread in Indonesia. Simple strategies exist to reduce freezing - for example, selective transport and storage of vaccines at ambient temperatures. The use of vaccine vial monitors reduces the risk associated with heat-damaged vaccines in these scenarios. Policy changes that allow limited storage of freeze-sensitive vaccines at temperatures >2-8 degrees C would enable flexible vaccine distribution strategies that could reduce vaccine freezing, reduce costs, and increase capacity. PMID:15042231

  8. Novel real-time diagnosis of the freezing process using an ultrasonic transducer.

    PubMed

    Tseng, Yen-Hsiang; Cheng, Chin-Chi; Cheng, Hong-Ping; Lee, Dasheng

    2015-01-01

    The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT) in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from -100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing). This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy. PMID:25946629

  9. Novel Real-Time Diagnosis of the Freezing Process Using an Ultrasonic Transducer

    PubMed Central

    Tseng, Yen-Hsiang; Cheng, Chin-Chi; Cheng, Hong-Ping; Lee, Dasheng

    2015-01-01

    The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT) in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from ?100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing). This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy. PMID:25946629

  10. ANNAGNPS: ACCOUNTING FOR SNOWPACK, SNOWMELT, FREEZING AND THAWING OF SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The watershed model, AnnAGNPS (Annualized AGricultural Non-Point Source Pollution model) has been enhanced by incorporating winter climate algorithms that account for frozen soil conditions. The model includes snowpack accumulation and melt, and the freeze/thaw process in the soil. Three major imp...

  11. Ultrasonic Measurements of Unconsolidated Saline Sediments During Freeze/Thaw Cycles: The Seismic Properties of Cryopeg Environments

    NASA Astrophysics Data System (ADS)

    Dou, S.; Ajo Franklin, J. B.

    2013-12-01

    Saline permafrost and cryopegs (hypersaline unfrozen layers/zones within permafrost) are widespread in the Arctic coastal area as a result of marine transgression and regression in recent geological history. Owing to the freezing-point depression effect of soluble salts, they contain more unfrozen water than non-saline frozen sediments when subjected to the same permafrost temperatures (e.g., from 0 to -15 °C). Mapping subsurface cryopeg structure remains a challenging geophysical task due to the poor penetration of GPR in highly conductive fluids and related limitations for lower frequency EM techniques. Seismic profiling, particularly surface wave characterization, provides one possible approach to delineate the extent of cryopeg bodies. However, interpretation of such surveys is currently limited by the sparse database of measurements examining the seismic properties of unconsolidated materials saturated with saline fluids at sub-zero temperatures. We present the results of experiments examining seismic velocity in the ultrasonic range for both synthetic and natural permafrost sediments during freeze/thaw cycles; in these experiments, use of a range of brine salinities allows us to evaluate the properties of cryopeg sediments at in-situ conditions, a prerequisite for quantitative interpretation of seismic imaging results. Because of the abundant unfrozen water and less developed inter-granular ice structure, the seismic properties of saline permafrost typically falls between frozen and unfrozen soils. We conducted ultrasonic measurements of a freeze-thaw cycle on 20-30 Ottawa sand (grain size 590-840 ?m) as well as natural mineral soils from the Barrow Environmental Observatory (BEO) saturated with brines of different salinities (0-2.5 M NaCl). For each salinity, seismic properties were measured using the ultrasonic (~1 MHz) pulse-transmission method in the temperature range from 20 to -30 °C. Similar to sediments saturated with low salinity fluids, seismic velocities increase significantly upon freezing in brine-saturated samples due to the formation of ice. However, substantial differences were observed: First, the onset of the velocity increase occurred at temperatures significantly below 0 °C (e.g., as low as -11.8 °C for 2.5 M pore-water salinity); Second, instead of having a stepwise velocity increase (temperature derivative of velocity on the order of 1000 m/s/°C) in the immediate neighborhood of the freezing-point as in non-saline samples, velocities in saline samples exhibit a gradual increase (dv/dT as low as ~70 m/s/°C) in temperatures between the freezing-point and the eutectic-point (~-25 °C) of NaCl solutions. Unusual increases in attenuation were also observed in the vicinity of freezing. Our results indicate that saline permafrost and cryopegs have distinct seismic properties when compared with their non-saline counterparts under the same thermal conditions. Moreover, the very low seismic velocities observed in this laboratory study are consistent with the low-velocity zones at Barrow, Alaska that were previously found through field-scale geophysical investigations.

  12. Depression among Asian Americans: Review and Recommendations

    PubMed Central

    Kalibatseva, Zornitsa; Leong, Frederick T. L.

    2011-01-01

    This article presents a review of the prevalence and manifestation of depression among Asian Americans and discusses some of the existing issues in the assessment and diagnosis of depression among Asian Americans. The authors point out the diversity and increasing numbers of Asian Americans and the need to provide better mental health services for this population. While the prevalence of depression among Asian Americans is lower than that among other ethnic/racial groups, Asian Americans receive treatment for depression less often and its quality is less adequate. In addition, the previous belief that Asians somatize depression may become obsolete as more evidence appears to support that Westerners may “psychologize” depression. The cultural validity of the current DSM-IV conceptualization of depression is questioned. In the course of the review, the theme of complexity emerges: the heterogeneity of ethnic Asian American groups, the multidimensionality of depression, and the intersectionality of multiple factors among depressed Asian Americans. PMID:21961060

  13. Depressive symptoms in neurodegenerative diseases.

    PubMed

    Baquero, Miquel; Martín, Nuria

    2015-08-16

    Depressive symptoms are very common in chronic conditions. This is true so for neurodegenerative diseases. A number of patients with cognitive decline and dementia due to Alzheimer's disease and related conditions like Parkinson's disease, Lewy body disease, vascular dementia, frontotemporal degeneration amongst other entities, experience depressive symptoms in greater or lesser grade at some point during the course of the illness. Depressive symptoms have a particular significance in neurological disorders, specially in neurodegenerative diseases, because brain, mind, behavior and mood relationship. A number of patients may develop depressive symptoms in early stages of the neurologic disease, occurring without clear presence of cognitive decline with only mild cognitive deterioration. Classically, depression constitutes a reliable diagnostic challenge in this setting. However, actually we can recognize and evaluate depressive, cognitive or motor symptoms of neurodegenerative disease in order to establish their clinical significance and to plan some therapeutic strategies. Depressive symptoms can appear also lately, when the neurodegenerative disease is fully developed. The presence of depression and other neuropsychiatric symptoms have a negative impact on the quality-of-life of patients and caregivers. Besides, patients with depressive symptoms also tend to further decrease function and reduce cognitive abilities and also uses to present more affected clinical status, compared with patients without depression. Depressive symptoms are treatable. Early detection of depressive symptoms is very important in patients with neurodegenerative disorders, in order to initiate the most adequate treatment. We review in this paper the main neurodegenerative diseases, focusing in depressive symptoms of each other entities and current recommendations of management and treatment. PMID:26301229

  14. Depressive symptoms in neurodegenerative diseases

    PubMed Central

    Baquero, Miquel; Martín, Nuria

    2015-01-01

    Depressive symptoms are very common in chronic conditions. This is true so for neurodegenerative diseases. A number of patients with cognitive decline and dementia due to Alzheimer’s disease and related conditions like Parkinson’s disease, Lewy body disease, vascular dementia, frontotemporal degeneration amongst other entities, experience depressive symptoms in greater or lesser grade at some point during the course of the illness. Depressive symptoms have a particular significance in neurological disorders, specially in neurodegenerative diseases, because brain, mind, behavior and mood relationship. A number of patients may develop depressive symptoms in early stages of the neurologic disease, occurring without clear presence of cognitive decline with only mild cognitive deterioration. Classically, depression constitutes a reliable diagnostic challenge in this setting. However, actually we can recognize and evaluate depressive, cognitive or motor symptoms of neurodegenerative disease in order to establish their clinical significance and to plan some therapeutic strategies. Depressive symptoms can appear also lately, when the neurodegenerative disease is fully developed. The presence of depression and other neuropsychiatric symptoms have a negative impact on the quality-of-life of patients and caregivers. Besides, patients with depressive symptoms also tend to further decrease function and reduce cognitive abilities and also uses to present more affected clinical status, compared with patients without depression. Depressive symptoms are treatable. Early detection of depressive symptoms is very important in patients with neurodegenerative disorders, in order to initiate the most adequate treatment. We review in this paper the main neurodegenerative diseases, focusing in depressive symptoms of each other entities and current recommendations of management and treatment. PMID:26301229

  15. Inverse Freezing in Mean-Field Models of Fragile Glasses

    E-print Network

    Mauro Sellitto

    2006-05-25

    A disordered spin model suitable for studying inverse freezing in fragile glass-forming systems is introduced. The model is a microscopic realization of the ``random-first order'' scenario in which the glass transition can be either continuous or discontinuous in thermodynamic sense. The phase diagram exhibits a first-order transition line between two fluid phases terminating at a critical point. When the interacting degrees of freedom are entropically favoured an inverse static glass transition and a double inverse dynamic freezing appear.

  16. Measuring and modeling hemoglobin aggregation below the freezing temperature.

    PubMed

    Rosa, Mónica; Lopes, Carlos; Melo, Eduardo P; Singh, Satish K; Geraldes, Vitor; Rodrigues, Miguel A

    2013-08-01

    Freezing of protein solutions is required for many applications such as storage, transport, or lyophilization; however, freezing has inherent risks for protein integrity. It is difficult to study protein stability below the freezing temperature because phase separation constrains solute concentration in solution. In this work, we developed an isochoric method to study protein aggregation in solutions at -5, -10, -15, and -20 °C. Lowering the temperature below the freezing point in a fixed volume prevents the aqueous solution from freezing, as pressure rises until equilibrium (P,T) is reached. Aggregation rates of bovine hemoglobin (BHb) increased at lower temperature (-20 °C) and higher BHb concentration. However, the addition of sucrose substantially decreased the aggregation rate and prevented aggregation when the concentration reached 300 g/L. The unfolding thermodynamics of BHb was studied using fluorescence, and the fraction of unfolded protein as a function of temperature was determined. A mathematical model was applied to describe BHb aggregation below the freezing temperature. This model was able to predict the aggregation curves for various storage temperatures and initial concentrations of BHb. The aggregation mechanism was revealed to be mediated by an unfolded state, followed by a fast growth of aggregates that readily precipitate. The aggregation kinetics increased for lower temperature because of the higher fraction of unfolded BHb closer to the cold denaturation temperature. Overall, the results obtained herein suggest that the isochoric method could provide a relatively simple approach to obtain fundamental thermodynamic information about the protein and the aggregation mechanism, thus providing a new approach to developing accelerated formulation studies below the freezing temperature. PMID:23808610

  17. Depression and Smoking

    MedlinePLUS

    Home » Tools » Depression Basics » Depression and Smoking Depression and Smoking Why is depression more common in smokers? Nobody knows for sure why smokers are more likely to have depression than non- ...

  18. Understanding Depression (For Parents)

    MedlinePLUS

    ... Keeping Kids Safe Concussions: What to Know Understanding Depression KidsHealth > Parents > Emotions & Behavior > Feelings & Emotions > Understanding Depression ... or a child you know, seems depressed. About Depression Depression isn't just bad moods and occasional ...

  19. Depression and Chronic Pain

    MedlinePLUS

    ... pain? For More Information on Depression Citations Reprints Depression and Chronic Pain Order a free hardcopy En ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ...

  20. Depression and Stroke

    MedlinePLUS

    ... Depression For More Information on Stroke Citations Reprints Depression and Stroke Order a free hardcopy En Español ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ...

  1. Depression and Cancer

    MedlinePLUS

    ... Depression For More Information on Cancer Citations Reprints Depression and Cancer Order a free hardcopy En Español ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ...

  2. Thermal analysis on the realization of the tin fixed point

    NASA Astrophysics Data System (ADS)

    Tsai, S. F.

    2013-09-01

    A study on the thermal analysis of a new tin fixed-point open cell within a new three-zone furnace was carried out. The stability at the setting temperatures of liquid-solid coexisting together with some degree Celsius lower and higher than the tin fixed point; and the axial uniformity of furnace while tin is still in solid phase were investigated and analyzed. The impurities effect on the depression in temperature was investigated in terms of ?T (Tobserved-T1/F=0) and the inverse of the melted fraction (1/F) relationship during the melting and the following freezing realizations at various temperature settings of furnace. These thermal analysis results were also compared with those estimated by the CCT-WG1 recommended SIE (sum of individual estimates) method, which leads to a temperature correction along with a corresponding uncertainty through the individual impurity content detected by GDMS (glow discharge mass spectrometry).

  3. Moments of charge fluctuations, pseudo-critical temperatures and freeze-out in heavy ion collisions

    E-print Network

    Frithjof Karsch

    2011-08-03

    We discuss universal properties of higher order cumulants of net baryon number fluctuations and point out their relevance for the analysis of freeze-out and critical conditions in heavy ion collisions at LHC and RHIC.

  4. Comment on the "Freeze-In" mechanism of dark matter production

    E-print Network

    John McDonald

    2011-12-07

    We point out an earlier implementation of the "freeze-in" mechanism for the production of very weakly-interacting dark matter. We also clarify a footnote given in 0911.1120 regarding this eariler paper.

  5. Freeze-in through portals

    SciTech Connect

    Blennow, Mattias; Fernandez-Martínez, Enrique; Zaldívar, Bryan E-mail: enrique.fernandez-martinez@uam.es

    2014-01-01

    The popular freeze-out paradigm for Dark Matter (DM) production, relies on DM-baryon couplings of the order of the weak interactions. However, different search strategies for DM have failed to provide a conclusive evidence of such (non-gravitational) interactions, while greatly reducing the parameter space of many representative models. This motivates the study of alternative mechanisms for DM genesis. In the freeze-in framework, the DM is slowly populated from the thermal bath while never reaching equilibrium. In this work, we analyse in detail the possibility of producing a frozen-in DM via a mediator particle which acts as a portal. We give analytical estimates of different freeze-in regimes and support them with full numerical analyses, taking into account the proper distribution functions of bath particles. Finally, we constrain the parameter space of generic models by requiring agreement with DM relic abundance observations.

  6. Water Freezing and Ice Melting.

    PubMed

    Ma?olepsza, Edyta; Keyes, Tom

    2015-12-01

    The generalized replica exchange method (gREM) is designed to sample states with coexisting phases and thereby to describe strong first order phase transitions. The isobaric MD version of the gREM is presented and applied to the freezing of liquid water and the melting of hexagonal and cubic ice. It is confirmed that coexisting states are well-sampled. The statistical temperature as a function of enthalpy, TS(H), is obtained. Hysteresis between freezing and melting is observed and discussed. The entropic analysis of phase transitions is applied and equilibrium transition temperatures, latent heats, and surface tensions are obtained for hexagonal ice ? liquid and cubic ice ? liquid with excellent agreement with published values. A new method is given to assign water molecules among various symmetry types. Pathways for water freezing, ultimately leading to hexagonal ice, are found to contain intermediate layered structures built from hexagonal and cubic ice. PMID:26642983

  7. Freezing of a Liquid Marble

    E-print Network

    Ali Hashmi; Adam Strauss; Jie Xu

    2012-07-03

    In this study, we present for the first time the observations of a freezing liquid marble. In the experiment, liquid marbles are gently placed on the cold side of a Thermo-Electric Cooler (TEC) and the morphological changes are recorded and characterized thereafter. These liquid marbles are noticed to undergo a shape transition from a spherical to a flying-saucer shaped morphology. The freezing dynamics of liquid marbles is observed to be very different from that of a freezing water droplet on a superhydrophobic surface. For example, the pointy tip appearing on a frozen water drop could not be observed for a frozen liquid marble. In the end, we highlight a possible explanation for the observed morphology.

  8. Freezing singularities in water drops

    E-print Network

    Enriquez, Oscar R; Winkels, Koen G; Snoeijer, Jacco H

    2011-01-01

    In this fluid dynamics video we show how a drop of water freezes into a singular shape when deposited on a cold surface. The process of solidification can be observed very clearly due to the change in refraction when water turns into ice. The drop remains approximately spherical during most of the process, with a freezing front moving upwards and smoothly following the interface. However, at the final stage of freezing, when the last cap of liquid turns into ice, a singular tip develops spontaneously. Interestingly, the sharp tip of the ice drop acts as a preferential site for deposition of water vapour, and a beautiful "tree" of ice crystals develops right at the tip. The tip singularity attracts the vapour in analogy to a sharp lightning rod attracting lightning.

  9. Freeze-dried microarterial allografts

    SciTech Connect

    Raman, J.; Hargrave, J.C.

    1990-02-01

    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.

  10. The effects of freezing and thawing on the aqueous availability of creosote contamination in soil

    SciTech Connect

    Bevel, A.; Hrudey, S.; Dudas, M.; Sego, D.

    1996-11-01

    A variety of methods have been tested in attempts to remediate contaminated sites. Fine-grained soils are extremely problematic to remediate, due to the high adsorption capacity of the fine soil particles and the trapping effect of soil particle micropores. It is well documented that freezing of soil causes particle restructuring and reorganization, with different pore structures found after freezing. Some factors affecting restructuring include soil moisture content, freezing rate, freezing end-point temperature, and number of freezing cycles. This poster presents an experiment that determines if freezing creosote contaminated soil improves accessibility of the creosote, by measuring aqueous phase contaminant dissolution. This method was selected since water is the most common solvent in naturally occurring systems, and water represents a worst-case scenario since many contaminants have low aqueous solubilities. Freezing is carried out under controlled laboratory conditions. Variables examined include moisture content, freezing rate, and soil contamination level. If contaminant availability is increased through soil freezing, remediation becomes an easier task in fine grained soils.

  11. Non-Toxic, Low-Freezing, Drop-In Replacement Heat Transfer Fluids

    NASA Technical Reports Server (NTRS)

    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.

  12. Temperature and flow measurements on near-freezing aviation fuels in a wing-tank model

    NASA Technical Reports Server (NTRS)

    Friedman, R.; Stockemer, F. J.

    1980-01-01

    Freezing behavior, pumpability, and temperature profiles for aviation turbine fuels were measured in a 190-liter tank, to simulate internal temperature gradients encountered in commercial airplane wing tanks. Two low-temperature situations were observed. Where the bulk of the fuel is above the specification freezing point, pumpout of the fuel removes all fuel except a layer adhering to the bottom chilled surfaces, and the unpumpable fraction depends on the fuel temperature near these surfaces. Where the bulk of the fuel is at or below the freezing point, pumpout ceases when solids block the pump inlet, and the unpumpable fraction depends on the overall average temperature.

  13. www.livestrong.org.livestrong.org Sadness and DepressionSadness and Depression

    E-print Network

    Brent, Roger

    - Support-Topics/Emotional-Effects-of-Cancer/Sadness-and-Depression#s#s) and Additional Resources (http://www.livestrong.org/Get-Help/Learn-About- Cancer/Cancer-Support-Topics/Emotional-Effects-of-Cancer/Sadness-and- Depression#a#a) documents experience sadness or depression at some point during their cancer experience. Talking with people you trust

  14. Resistant depressions.

    PubMed

    Stranieri, Giuseppe

    2014-11-01

    The concept of Resistant Depression was introduced for the first time in 1974 by Leiman. Despite the numerous studies in this regard, it was not possible to give a precise definition of this problem and to identify a safe etiology. This work aims to contribute through a literature review and exposure of two clinical cases, to better define and analyze this phenomenon by assuming the possible therapeutic strategies for patients with resistant depression. PMID:25413517

  15. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary, Processing, and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  16. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary, Processing, and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  17. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary, Processing, and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  18. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary, Processing, and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  19. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary, Processing, and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  20. Status of Chemical Freeze-Out

    E-print Network

    J. Cleymans; H. Oeschler; K. Redlich; S. Wheaton

    2006-07-14

    The status of the energy dependence of the chemical freeze-out temperature and chemical potential obtained in heavy ion collisions is presented. Recent proposals for chemical freeze-out conditions are compared.

  1. Waste freezing, remote retrieval technology

    SciTech Connect

    Not Available

    1993-01-01

    Idaho National Engineering Laboratory (INEL) scientists have successfully demonstrated a process of freezing soil and buried waste and retrieving it using remotely operated tools. Early results indicate that this cryogenic retrieval process may reduce risk to workers and protect the environment from airborne and liquid contaminants during actual waste cleanup projects.

  2. [MAJOR DEPRESSION AND PERSONALIZED MEDICINE].

    PubMed

    Pitchot, W

    2015-01-01

    Depression is a major public health problem. According to the World Health Organization (OMS), depression is currently the second cause of disability in developing countries. Depression is also one of the most frequent mental illnesses. When treating depression, the main objective is to achieve complete remission and to prevent recurrence. Unfor-tunately, in clinical practice, this aim is particularly difficult to reach. Indeed, in clinical trials and in naturalistic studies, remission levels are rather low. The challenge is to individualize the treatment of depression taking account clinical specificities, but also advances in the field of biological and genetic research. Today, intense psychiatric research tries to discover biomarkers to predict treatment response. Because individuals are highly different from a biological, psychological and sociological point of view, more personalized therapeutic approaches are recommended. PMID:26285462

  3. Combined infrared and freeze-drying.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The drying of the combined infrared (IR) and freeze-drying of food materials has been shown to be very rapid compared to regular freeze drying (FD). The resulting tissue structure of products processed with sequential infrared and freeze drying (SIRFD) tends to have higher crispness than those proce...

  4. Freeze Thaw Durability of Modern Concrete Mixtures

    E-print Network

    Freeze Thaw Durability of Modern Concrete Mixtures Robert Felice John Michael Freeman Tyler Ley, P photos #12;Why Do We Add Air to Concrete? · Air-entrained bubbles are the key to the freeze-thaw resistance of concrete · Smaller bubbles are more effective in providing freeze-thaw resistance than larger

  5. Morphological instability in freezing colloidal suspensions

    E-print Network

    Wettlaufer, John S.

    Morphological instability in freezing colloidal suspensions BY STEPHEN S. L. PEPPIN 1,2, *, M. GRAE of colloidal systems is that they do not freeze uniformly. Instead the ice segregates, aligning the expelled particles into different configurations depending on the freezing conditions (figure 1). One of the major

  6. Improvement of Freezing Quality of Food by Pre-dehydration with Microwave-Vacuum Drying

    NASA Astrophysics Data System (ADS)

    Hamidi, Nurkholis; Tsuruta, Takaharu

    Partial dehydration by microwave vacuum drying has been applied to tuna, oyster and mackerel prior to freezing in order to reduce quality damages due to freezing and thawing. Samples were dehydrated at pressure of 4kPa and temperature lower than 25°C. Two cooling conditions were tested in the experiment by using the freezing chamber of temperatures -20°C and -80°C. The experimental results showed that decreasing the water content in tuna could lower the freezing point temperature and made the freezing time shorter. It was also found that removing some water was effective to reduce the size of ice crystal and the drip loss in mackerel. After thawing, the pre-dehydrated mackerel showed better microstructure than that frozen without pre-treatment. Furthermore, the sensory tests have been done by a group of panelist for the evaluation on aroma, flavor, and general acceptability of mackerels.

  7. Heat pump with freeze-up prevention

    DOEpatents

    Ecker, Amir L. (Dallas, TX)

    1981-01-01

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid prevents freeze up of the second heat exchanger by keeping the temperature above the dew point; and, optionally, provides heat for efficient operation.

  8. Crystal structures and freezing of dipolar fluids

    E-print Network

    B. Groh; S. Dietrich

    2000-10-21

    We investigate the crystal structure of classical systems of spherical particles with an embedded point dipole at T=0. The ferroelectric ground state energy is calculated using generalizations of the Ewald summation technique. Due to the reduced symmetry compared to the nonpolar case the crystals are never strictly cubic. For the Stockmayer (i.e., Lennard-Jones plus dipolar) interaction three phases are found upon increasing the dipole moment: hexagonal, body-centered orthorhombic, and body-centered tetragonal. An even richer phase diagram arises for dipolar soft spheres with a purely repulsive inverse power law potential $\\sim r^{-n}$. A crossover between qualitatively different sequences of phases occurs near the exponent $n=12$. The results are applicable to electro- and magnetorheological fluids. In addition to the exact ground state analysis we study freezing of the Stockmayer fluid by density-functional theory.

  9. Freeze Technology for Nuclear Applications - 13590

    SciTech Connect

    Rostmark, Susanne C.; Knutsson, Sven; Lindberg, Maria

    2013-07-01

    Freezing of soil materials is a complicated process of a number of physical processes: - freezing of pore water in a thermal gradient, - cryogenic suction causing water migration and - ice formation expanding pores inducing frost heave. Structural changes due to increase of effective stress during freezing also take place. The over consolidation gives a powerful dewatering/drying effect and the freeze process causes separation of contaminates. Artificial ground freezing (AGF is a well established technique first practiced in south Wales, as early as 1862. AGF is mostly used to stabilize tunnels and excavations. During the last ten years underwater applications of freeze technologies based on the AGF have been explored in Sweden. The technology can, and has been, used in many different steps in a remediation action. Freeze Sampling where undisturbed samples are removed in both soft and hard sediment/sludge, Freeze Dredging; retrieval of sediment with good precision and minimal redistribution, and Freeze Drying; volume reduction of contaminated sludge/sediment. The application of these technologies in a nuclear or radioactive environment provides several advantages. Sampling by freezing gives for example an advantage of an undisturbed sample taken at a specified depth, salvaging objects by freezing or removal of sludges is other applications of this, for the nuclear industry, novel technology. (authors)

  10. Freeze chromatography method and apparatus

    DOEpatents

    Scott, C.D.

    1987-04-16

    A freeze chromatography method and apparatus are provided which enable separation of the solutes contained in a sample. The apparatus includes an annular column construction comprising cylindrical inner and outer surfaces defining an annular passage therebetween. One of the surfaces is heated and the other cooled while passing an eluent through the annular passageway so that the eluent in contact with the cooled surface freezes and forms a frozen eluent layer thereon. A mixture of solutes dissolved in eluent is passed through the annular passageway in contact with the frozen layer so that the sample solutes in the mixture will tend to migrate either toward or away the frozen layer. The rate at which the mixture flows through the annular passageway is controlled so that the distribution of the sample solutes approaches that at equilibrium and thus a separation between the sample solutes occurs. 3 figs.

  11. Slow-roll freezing quintessence

    E-print Network

    Sourish Dutta; Robert J. Scherrer

    2011-08-03

    We examine the evolution of quintessence models with potentials satisfying (V'/V)^2freezing phase, in which the equation of state parameter w decreases with time, followed by slow thawing evolution, for which w increases with time. These models resemble constant-V models at early times but diverge at late times. Our analytic approximation gives results in excellent agreement with exact numerical evolution.

  12. Postpartum Depression Facts

    MedlinePLUS

    ... help? Where can I find more information? Postpartum Depression Facts Order a free hardcopy With postpartum depression, ... for herself or her family. What is postpartum depression? Postpartum depression is a mood disorder that can ...

  13. Older Adults and Depression

    MedlinePLUS

    ... on Older Adults and Depression Older Adults and Depression Order a free hardcopy En Español Introduction Do ... If so, you may have depression. What is depression? Everyone feels down or sad sometimes, but these ...

  14. Depression and Parkinson's Disease

    MedlinePLUS

    ... For More Information on Parkinson's Disease Citations Reprints Depression and Parkinson's Disease Order a free hardcopy En ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ...

  15. The thermodynamics of freezing soils

    NASA Astrophysics Data System (ADS)

    Dall'Amico, Matteo; Rigon, Riccardo; Gruber, Stephan; Endrizzi, Stefano

    2010-05-01

    In this work a throughout derivation of the soil freezing process is performed, from the thermodynamic equilibrium to the derivation of the water and ice content in the ground. Starting from a capillary tube schematization for the soil and the findings of Loch (1978), the generalized Clapeyron equation may be directly obtained by the Gibbs-Duhem identity. In this equation, however, the ice pressure complicates the formulation as it adds an unknown to the thermodynamic equilibrium. The only way to obtain the common generalized Clapeyron equation often used in literature is to hypothesize the behavior ''freezing=drying'' as proposed by Miller (1963). In this case the pressure at the ice-water interface is equal to the air-water interface, and so the ice pressure may be set constant and equal to the zero gauge pressure given by air pressure. This assumption, often tacitly assumed in literature, implies precise limitations on the physical processes that may be dealt with. In particular, frost heave may not be modeled. The objective of this work is to derive the thermodynamic equilibrium of the ice and water phases in a porous medium, to clarify the ''freezing=drying'' assumption and to propose a fully explicit formulation for the equilibrium where the ice pressure is added to the set of unknowns.

  16. Survival of freezing by free-living Antarctic soil nematodes.

    PubMed

    Convey, P; Worland, M R

    2000-01-01

    Free-living microbivorous nematodes become numerically dominant in Antarctic terrestrial faunas as environmental conditions become more severe, while also reaching very high levels of abundance in moist, vegetated habitats. Nematodes have little resistance to freezing via exogenous ice nucleation, such as would occur as their microhabitat freezes. We report the results of experiments testing the ability of seven maritime Antarctic nematode taxa to survive freezing in small water droplets at high sub-zero temperatures. Isolated individuals of these species possessed supercooling characteristics similar to those previously reported (supercooling points -6 to -25 degree C). When frozen in water at -3 to -6 degree C, most showed high (> 70%) survival both (i) after rapid cooling (1 degree C/min) to c. -60 degree C followed by immediate rewarming, and (ii) when held for 7-12 h at either -10 or -30 degree C, although the proportions surviving varied between species. We propose that the ability to survive freezing while fully hydrated at high sub-zero temperatures is one of the most important aspects of these species' survival tactics. PMID:12148024

  17. Freezing Rate Due to Heterogeneous Nucleation.

    NASA Astrophysics Data System (ADS)

    Vali, Gabor

    1994-07-01

    The heterogeneous nucleation of ice from supercooled water is influenced by the nature of the foreign nuclei that serve as the sites for ice embryo formation, and by the stochastic nature of the process of embryo growth to critical size. The relative roles of these two factors have been the subject of some debate, especially as they influence the way nucleation of ice is modeled in clouds. `Freezing rate' is defined as the time-dependent rate at which a population of macroscopically identical samples (e.g., drops in a volume of air) freeze due to the nuclei contained in them. Freezing rate is the combined result of nucleus content and of time dependence. The time-dependent freezing rate model (TDFR) is consistent with available empirical evidence. For droplets cooled at rates of the order of 1°C per min, the nucleus content, or nucleus spectrum, predicts the freezing rate with reasonable accuracy. For samples exposed to a fixed temperature, the time dependence of the freezing rate becomes important, but the probability of freezing is not the same for each individual of the sample population. Stochastic models are not supported by the results. Application of the TDFR model and use of measured freezing nucleus data for precipitation provide a basis for the description of ice formation via immersion-freezing nucleation in cloud models. Limitations to full development of these models arise from inadequate knowledge about the freezing nucleus content of cloud water as a function of cloud evolution.

  18. Improved cryofixation applicable to freeze etching.

    PubMed

    Bachmann, L; Schmitt, W W

    1971-09-01

    Freeze etching of solute model systems (e.g., glycerol or ferritin solutions) demonstrates that cryofixation can introduce serious artifacts due to the segregation of the dissolved or dispersed material from the solvent. Since, in principle, this problem can be reduced by increasing the cooling rate, a new technique has been developed which combines spray freezing with freeze etching. This spray-freeze-etching is applied by first spraying the specimen into a liquid cryomedium. The frozen droplets are then "glued" together with butylbenzene to form a regular freeze-etch specimen, while the temperature of the sample is kept at -85 degrees C. The results obtained by spray-freeze-etching are far superior to those obtained by standard freezing. Our results, using 5% glycerol as a test specimen, are equivalent to those obtained by the high-pressure method (1). The reduction of segregation during freezing makes freeze etching a method applicable for the investigation of solute systems. Furthermore, the study of unicellular organisms or cellular fractions by freeze etching without the use of antifreeze is made possible. PMID:4943787

  19. Additional weight load increases freezing of gait episodes in Parkinson's disease; an experimental study.

    PubMed

    Mensink, Senja H G; Nonnekes, Jorik; van Bon, Geert; Snijders, Anke H; Duysens, Jacques; Weerdesteyn, Vivian; Bloem, Bastiaan R; Oude Nijhuis, Lars B

    2014-05-01

    Freezing of gait is an episodic gait disorder,characterized by the inability to generate effective forward stepping movements. The pathophysiology underlying freezing of gait remains insufficiently understood, and this hampers the development of better treatment strategies.Preliminary evidence suggests that impaired force control during walking may contribute to freezing episodes, with difficulty to unload the swing leg and initiate the swing phase. Here, we used external loading to manipulate force control and to investigate its influence on freezing of gait.Twelve Parkinson's disease patients with freezing of gait performed three contrasting tasks: (1) loaded gait while wearing a belt fortified with lead weights; (2) weight supported gait using a parachute harness connected to a rigid metal cable running above the gait trajectory; and (3)normal gait. Gait tasks were used to provoke freezing episodes, including rapid 360° turns. Freezing episodes were quantified using blinded, videotaped clinical assessment. Furthermore, ground reaction forces and body kinematics were recorded. Loading significantly increased the mean number of freezing episodes per trial compared to the normal gait condition (P<0.05), but the effect of weight support was not consistent. Loading particularly increased the number of freezing episodes during rapid short steps. Step length was significantly smaller during loaded gait compared to normal gait (P<0.05), but changes in anticipatory postural adjustments were not different.Our results may point to impaired force control playing a key role in freezing of gait. Future studies should further investigate the mechanism, i.e., the contribution of deficient load feedback, and evaluate which forms of weight support might offer treatment opportunities. PMID:24658705

  20. Transverse freezing of thin liquid films

    NASA Astrophysics Data System (ADS)

    Beerman, Michael

    A pair of coupled non-linear partial differential equations is derived using lubrication theory that govern the morphology of a thin, liquid film of a pure and a binary metal alloy, bounded by the liquid's solid phase and a passive gas phase. The analysis is motivated by the directional freezing of metallic foams, and is a first attempt to model transverse freezing in thin films that form in foam networks, but also applies to thin film layers in general. Both the no-slip crystal-melt and the free melt-gas interfaces are deformable. The governing pair of non-linear differential equations for the most general case incorporate crystal-melt and melt-gas surface tension, latent heat, heat transfer, volume change, molecular interactions, thermocapillary and dilute phase concentration effects. Linear analysis of a uniform film reveals a variety of instabilities. A unique wavenumber is selected at the onset of instability in the case of an applied temperature gradient with vanishing crystal-melt surface tension. This system reproduces the isothermal result for a rigid solid-liquid interface in which a band of wavenumbers is unstable. A new long-wave instability has been identified, for the case with CM surface tension, that is due to the coupling of the interfaces. Numerical solutions of the fully non-linear system provide film evolution and rupture times, and show that, near the critical conditions, rupture can occur by the growth of standing or traveling waves. The numerics also reveals complex non-linear interactions between unstable modes. It is found that for most unstable initial conditions, the crystal-melt interface retreats by melting away from the tip region of the encroaching melt-gas interface due to a rise in heat flux as the film thins near the rupture point.

  1. Spin Probe ESR Signature of Freezing in Water: Is it Global or Local?

    E-print Network

    Debamalya Banerjee; S. V. Bhat

    2008-10-26

    First systematic spin probe ESR study of water freezing has been conducted using TEMPOL and TEMPO as the probes. The spin probe signature of the water freezing has been described in terms of the collapse of narrow triplet spectrum into a single broad line. This spin probe signature of freezing has been observed at an anomalously low temperature when a milimoler solution of TEMPOL is slowly cooled from room temperature. A systematic observation has revealed a spin probe concentration dependence of these freezing and respective melting points. These results can be explained in terms of localization of spin probe and liquid water, most probably in the interstices of ice grains, in an ice matrix. The lowering of spin probe freezing point, along with the secondary evidences, like spin probe concentration dependence of peak-to-peak width in frozen limit signal, indicates a possible size dependence of these localizations/entrapments with spin probe concentration. A weak concentration dependence of spin probe assisted freezing and melting points, which has been observed for TEMPO in comparison to TEMPOL, indicates different natures of interactions with water of these two probes. This view is also supported by the relaxation behavior of the two probes.

  2. Predicting Freezing for Some Repulsive Potentials

    SciTech Connect

    Khrapak, S. A.; Morfill, G. E.

    2009-12-18

    We propose a simple method to approximately predict the freezing (fluid-solid) phase transition in systems of particles interacting via purely repulsive potentials. The method is based on the striking universality of the freezing curve for the model Yukawa and inverse-power-law interactions. This method is applied to draw an exemplary phase diagram of complex plasmas. We suggest that it can also be used to locate freezing transition in other substances with similar properties of interaction.

  3. Freezing techniques defeat ground water problems

    SciTech Connect

    Not Available

    1983-02-01

    The sinking of a new shaft at Walsum Colliery, West Germany, is described. The 640 m of strata above the coal seams were known to be unstable and include the Bunter Sandstone. The shaft is also within 1 km of the River Rhine. Freezing techniques were therefore adopted. Details of the freezing operation are given, including the drilling of the freezing holes and the determination of the size and strength of the ice wall.

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

    EPA Science Inventory

    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...

  5. Scanning electron microscopy of muscle myofibrils after high pressure freezing and freeze-substitution-staining.

    PubMed

    Malecki, M; Greaser, M L

    1993-03-01

    A novel approach to study the three dimensional ultrastructure of organelles and cells by means of scanning electron microscopy is described. Muscle myofibrils have been used in the development of the techniques since their structure is well characterized using conventional electron microscopic methods. Myofibrils in rigor buffer (with no cryo-protectants or pressure sealants) were frozen at high pressure (2300 bar) within specially designed chambers. The frozen specimens were then freeze-substituted-stained with methanol containing tungsten and iron salts and finally critical point dried. These methods allowed scanning electron microscopic observations of the organization of individual filaments within whole myofibrils over several sarcomeres. Images obtained showed excellent structural preservation with three dimensional information which is not available with other electron microscopic techniques. Success in these approaches was ascribed to (a) rapid and uniform freezing at high pressure without ice segregation patterns, (b) uniform electro-conductivity of the specimen closely attached to the polished carbon piston/carrier, and (c) good electron emission (secondary and back-scattered) from the metal incorporated into the myofibril structure without additional coating. PMID:7686303

  6. Freeze out in narrow and wide layers

    E-print Network

    V. K. Magas; L. P. Csernai; E. Molnar

    2006-01-19

    The freeze out of particles from a layer of finite thickness is discussed in a phenomenological kinetic model. The proposed model, based on the Modified Boltzman Transport Equation, is Lorentz invariant and can be applied equally well for the freeze out layers with space-like and time-like normal vectors. It leads to non-equilibrated post freeze out distributions. The dependence of the resulting distribution on the thickness of the layer is presented and discussed for a space-like freeze out scenario.

  7. Measuring freezing tolerance: survival and regrowth assays.

    PubMed

    Skinner, Daniel Z; Garland-Campbell, Kimberly

    2014-01-01

    Screening plants for freezing tolerance under tightly controlled conditions is an invaluable technique for studying freezing tolerance and selecting for improved winterhardiness. Artificial freezing tests of cereal plants historically have used isolated crown and stem tissue prepared by "removing all plant parts 3 cm above and 0.5 cm below the crown tissue" (Fowler et al., Crop Sci 21:896-901, 1981). Here, we describe a method of conducting freezing tolerance tests using intact plants grown in small horticultural containers, including suggested methods for collecting and analyzing the data. PMID:24852624

  8. 47 CFR 64.1190 - Preferred carrier freezes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Preferred carrier freezes. 64.1190 Section 64....1190 Preferred carrier freezes. (a) A preferred carrier freeze (or freeze) prevents a change in a subscriber's preferred carrier selection unless the subscriber gives the carrier from whom the freeze...

  9. Leica EM AFS2 Automatic Freeze Substitution System

    E-print Network

    Chapman, Michael S.

    Leica EM AFS2 Automatic Freeze Substitution System Leica EM FSP Freeze Substitution Processor #12 working range · "Deep Freeze" allows sample transfer at temperatures below -140 °C · Transfer function "TF steel working platform Leica EM AFS2 Freeze Substitution has never been easier... Freeze Substitution

  10. 47 CFR 64.1190 - Preferred carrier freezes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Preferred carrier freezes. 64.1190 Section 64....1190 Preferred carrier freezes. (a) A preferred carrier freeze (or freeze) prevents a change in a subscriber's preferred carrier selection unless the subscriber gives the carrier from whom the freeze...

  11. 47 CFR 64.1190 - Preferred carrier freezes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Preferred carrier freezes. 64.1190 Section 64....1190 Preferred carrier freezes. (a) A preferred carrier freeze (or freeze) prevents a change in a subscriber's preferred carrier selection unless the subscriber gives the carrier from whom the freeze...

  12. 47 CFR 64.1190 - Preferred carrier freezes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Preferred carrier freezes. 64.1190 Section 64....1190 Preferred carrier freezes. (a) A preferred carrier freeze (or freeze) prevents a change in a subscriber's preferred carrier selection unless the subscriber gives the carrier from whom the freeze...

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Kinetics of osmotic water flow across cell membranes in non-ideal solutions during freezing and thawing.

    PubMed

    Weng, Lindong; Li, Weizhong; Zuo, Jianguo

    2010-10-01

    Cryopreservation requires quantitatively analytical models to simulate the biophysical responses of biomaterials during cryopreservation. The Mazur model and other improved ones, such as Karlsson model concerning solutions containing cryoprotectants (CPA), are somehow precluded by some minor points, particularly, the assumption of ideal solutions. To avoid the ideal solution assumption, in this study a new method is developed to simulate water transport across cell membranes in non-ideal solutions during cooling and thawing. The comparison between osmolalities calculated by the linear freezing-point depression used in this new method and other non-ideal ones is conducted and a good agreement is achieved. In addition, in an ideal case, besides a theoretical agreement, this new approach has been validated by its numerical simulation results. Comparisons between this new approach and the traditional ones with an ideal solution assumption have been conducted based on a spherical hypothetical cell. The main results are (1) the predicted non-ideal intracellular water content is larger than the ideal results; (2) the concentration of CPA solutions is directly proportional to the deviation between the non-ideal and ideal curves. In the end, this study presents a direct description of the degree of subcooling of the protoplasm during dynamic cooling. This study demonstrates that our experimental data-based method is a valid one with clear physical interpretations, convenient expressions and a more extensive application room than traditional ones. PMID:20654609

  15. Metabolic activity of permafrost bacteria below the freezing point

    NASA Technical Reports Server (NTRS)

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  16. Cavitation in water under tension near the freezing point

    SciTech Connect

    Sosikov, V. A. Utkin, A. V.; Fortov, V. E.

    2008-05-15

    Experiments are reported on cavitation in water at an initial temperature of 0.7 deg. C under the dynamic tension created when a compression wave interacts with a free liquid surface. It is found that the tensile strength of water increases from 20 to 50 MPa as the strain rate is varied from 1.8 x 10{sup 4} to 5.2 x 10{sup 4} s{sup -1}. It is shown that the phase state of water obtained in experiments is in a double metastable region.

  17. Influence of formulation pH and suspension state on freezing-induced agglomeration of aluminum adjuvants.

    PubMed

    Salnikova, Maya S; Davis, Harrison; Mensch, Christopher; Celano, Lauren; Thiriot, David S

    2012-03-01

    Freezing and thawing of vaccines containing aluminum adjuvants can lead to formation of aggregates and loss in vaccine potency. We sought to understand whether and to what extent the freeze-thaw damage to aluminum adjuvants would differ based on suspension state (flocculation and settlement) at the time of freezing. As flocculation and settlement characteristics of aluminum adjuvants are driven largely by the electrostatic charges on the adjuvant particles, which, in turn, are strongly influenced by the pH of the suspension, we conducted freeze-thaw studies on both Adjuphos and Alhydrogel™ samples at three pH levels (4, 6.5, and 7.2) in buffer solutions with 9% sucrose. Significantly less aggregation occurred in the buffered sucrose solutions at the pH furthest from the aluminum adjuvant point of zero charge during slow freezing at -20°C. The freezing-induced aggregation for the samples with 9% sucrose at each pH was minimal during fast freezing at -70°C and -115°C. Suspensions that were flocculated and settled to a greater extent experienced the most freeze-thaw aggregation, whereas suspensions that were frozen before significant flocculation and settlement occurred showed little or no aggregation. Because pH of formulation can affect flocculation and settling time, it indirectly affects the extent of freeze-thaw aggregation. PMID:22113733

  18. Adolescence and Depression.

    ERIC Educational Resources Information Center

    Wisconsin Clearinghouse, Madison.

    This booklet begins with a poem written by an adolescent undergoing psychotherapy for depression, then goes on to describe what depression is and to examine sex and age differences related to depression. The difference between clinical depression and feeling blue is explained. Various therapies used in the treatment of depression are identified.…

  19. Depression: What We Know.

    ERIC Educational Resources Information Center

    Lobel, Brana; Hirschfeld, Robert M. A.

    This booklet is concerned with the area of clinical depression. Questions about clinical depression are briefly answered in an overview section and are examined in greater detail in the five chapters that follow. In chapter 1, depression is defined and various types of depression are identified. The origins of depression are explored in the second…

  20. HOST CADAVERS PROTECT ENTOMOPATHOGENIC NEMATODES DURING FREEZING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four species of insect-killing nematodes were exposed to freezing temperatures while inside their hosts. Survival was assessed by observing live and dead nematodes inside cadavers and by counting the infective juveniles (IJs) tht emerged after freezing. We 1) measured the effects of 24 hours of fr...

  1. Improving Forecasts of Freezing Rain at ECMWF

    NASA Astrophysics Data System (ADS)

    Tsonevsky, Ivan; Forbes, Richard; Hewson, Tim

    2015-04-01

    Freezing rain events, though relatively rare, can be extremely debilitating and dangerous for society, with recovery times of order months or even years. Analysis of forecasts of past events by the operational ECMWF Integrated Forecast System (IFS) showed a strong tendency to incorrectly represent freezing rain as snow. Investigations highlighted that this was primarily because the re-freezing process in IFS, following hydrometeors as they descend, was parametrised with the same time-scale as the melting process. In reality the time-scale for re-freezing should, in general, be much longer. The model physics were changed accordingly, and the results in terms of forecast quality were positive and very striking. Coupled with these physics changes new IFS output was developed for users which shows precipitation type at the surface (rain, snow, wet snow, sleet, freezing rain, ice pellets). The changes to the physics will be described in detail, and their impact will be illustrated by comparing forecast output for past events in new and old model versions, in terms of precipitation type and intensity. Illustrations will include short-range deterministic forecasts from 'HRES' (the high resolution ECMWF model), and longer range probabilistic forecasts of freezing rain occurrence from the ensemble. There will also be reference to issues requiring further work/investigation, such as high level convection in potential freezing rain cases, freezing drizzle generated in supercooled shallow clouds, and IFS retention of the 'warm nose' in which melting occurs.

  2. The principles of freeze-drying.

    PubMed

    Adams, Gerald D J; Cook, Isobel; Ward, Kevin R

    2015-01-01

    This chapter provides an up-to-date overview of freeze-drying (lyophilization) with particular relevance to stabilizing live cells or viruses for industrial applications as vaccines or seed culture. The chapter discusses the importance of formulation, cycle development, validation, and the need to satisfy pharmaceutical regulatory requirements necessary for the commercial exploitation of freeze-dried products. PMID:25428004

  3. A Possible Role for Immersion Freezing in

    E-print Network

    Eloranta, Edwin W.

    A Possible Role for Immersion Freezing in Mixed-phase Stratus Clouds Gijs de Boer T. Hashino, G and Klett, 1997) (Contact) - Nucleation through free IN - Immersion nucleation - Condensation nucleation;Jensenetal., 1998) SplinterEjection(>-8°C) (HeymsfieldandMossop, 1984) #12;Immersion Freezing Polar Cloud

  4. A Phase-Field Solidification Model of Almost Pure ITS-90 Fixed Points

    NASA Astrophysics Data System (ADS)

    Large, M. J.; Pearce, J. V.

    2014-07-01

    A two-dimensional axisymmetric phase-field model of thermo-solutal solidification in freezing-point cells used for calibrating standard platinum resistance thermometers for realization and dissemination of the International Temperature Scale of 1990 is presented. The cell is essentially a graphite crucible containing an ingot of very pure metal (of order 99.9999 %). A graphite tube is inserted along the axis of the ingot to enable immersion of the thermometer in the metal. In this study, the metal is tin (freezing temperature of ). During the freezing of these cells, a steady, reproducible temperature is realized, with a defined temperature that can be used to calibrate thermometers with uncertainties mK. The model is applied to understand the effect of experimental parameters, such as initiation technique and furnace homogeneity, on the measured freezing curve. Results show that freezing curves whose behavior is consistent with the Scheil theory of solidification can be obtained with a specific furnace temperature profile, and provided that the freeze is of a long duration, the results are consistent with previous one-dimensional models and experiments. Morphological instability is observed with the inner interface initiation technique, causing the interface to adopt a cellular structure. This elevates the measured temperature, in accordance with the Gibbs-Thomson effect. In addition, the influence of initiation techniques on the solidification behavior is examined. The model indicates that an initially smooth inner mantle can `de-wet' from the thermometer well-forming agglomerated solid droplets, following recalescence, under certain conditions. This manifests as a measured temperature depression due to the Gibbs-Thomson effect, with a magnitude of to in simulations. The temperature rises to that of the stable outer mantle as freezing progresses and the droplets re-melt. It is demonstrated that the effect occurs below a critical mantle thickness. A physical explanation for the origin of the effect is offered showing that it is consistent with solid-state de-wetting phenomena. Consideration is also given to the limitations of the current model configuration.

  5. Freeze-drying for morphological control of high performance semi-interpenetrating polymer networks. III

    NASA Technical Reports Server (NTRS)

    Hsiung, H. J.; Hansen, M. G.; Pater, R. H.

    1991-01-01

    The feasibility of using a freeze-drying (solvent removal by sublimation) approach for controlling the morphology of a high-performance semi-IPN is assessed. A high-performance thermoplastic polyimide and commercially available 4,4'-bismaleimide diphenylenemethane were dissolved in a solvent, 1,3,5-trioxane. The solvent was removed from the constituents by freeze-drying. For purposes of comparison, the constituents were dissolved in a high-boiling-point solvent, N,N-dimethylformamide. The solvent was removed from the solution by evaporation. The physical and mechanical properties and phase morphology of the neat resins and composites prepared by freeze-drying and traditional solution methods are presented and compared. It is concluded that the TG is higher and that the magnitude of minor constituent separation is less in the freeze-dry processed materials than for the processed solution.

  6. Microphysical Modelling of the 1999-2000 Arctic Winter. 3; Impact of Homogeneous Freezing on PSCs

    NASA Technical Reports Server (NTRS)

    Drdla, K.

    2003-01-01

    Simulations of the 1999-2000 winter have tested the effect on polar stratospheric clouds (PSCs) of the homogeneous freezing of liquid ternary solutions into nitric acid trihydrate (NAT) and nitric acid dihydrate (NAD). Proposed laboratory-derived volume-based and surface-based homogeneous freezing rates have both been examined, including different assumptions about the extrapolation of laboratory measurements to atmospheric conditions. Widespread PSC formation and denitrification are possible in several of the scenarios examined. However, the simulations are all unable to explain the solid-phase PSCs observed early in the 1999-2000 winter, and are unable to reproduce the measured extent of vortex denitrification. These problems can both be attributed to the relatively cold temperatures, more than 5 K below the NAT condensation point, necessary for effective homogeneous freezing. Therefore synoptic-scale homogeneous freezing appears unlikely to be the primary mechanism responsible for solid-phase PSC formation.

  7. Colloid-facilitated mobilization of metals by freeze-thaw cycles.

    PubMed

    Mohanty, Sanjay K; Saiers, James E; Ryan, Joseph N

    2014-01-21

    The potential of freeze-thaw cycles to release colloids and colloid-associated contaminants into water is unknown. We examined the effect of freeze-thaw cycles on the mobilization of cesium and strontium in association with colloids in intact cores of a fractured soil, where preferential flow paths are prevalent. Two intact cores were contaminated with cesium and strontium. To mobilize colloids and metal cations sequestered in the soil cores, each core was subjected to 10 intermittent wetting events separated by 66 h pauses. During the first five pauses, the cores were dried at room temperature, and during last five pauses, the cores were subjected to 42 h of freezing followed by 24 h of thawing. In comparison to drying, freeze-thaw cycles created additional preferential flow paths through which colloids, cesium, and strontium were mobilized. The wetting events following freeze-thaw intervals mobilized about twice as many colloids as wetting events following drying at room temperature. Successive wetting events following 66 h of drying mobilized similar amounts of colloids; in contrast, successive wetting events after 66 h of freeze-thaw intervals mobilized greater amounts of colloids than the previous one. Drying and freeze-thaw treatments, respectively, increased and decreased the dissolved cesium and strontium, but both treatments increased the colloidal cesium and strontium. Overall, the freeze-thaw cycles increased the mobilization of metal contaminants primarily in association with colloids through preferential flow paths. These findings suggest that the mobilization of colloid and colloid-associated contaminants could increase when temperature variations occur around the freezing point of water. Thus, climate extremes have the potential to mobilize contaminants that have been sequestered in the vadose zone for decades. PMID:24377325

  8. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  9. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  10. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  11. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  12. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  13. 7 CFR 305.18 - Quick freeze treatment schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Quick freeze treatment schedule. 305...PHYTOSANITARY TREATMENTS Quick Freeze Treatments § 305.18 Quick freeze treatment schedule. (a...United States or its territorial waters, or is otherwise disposed...

  14. Homogeneous freezing nucleation of stratospheric solution droplets

    NASA Technical Reports Server (NTRS)

    Jensen, Eric J.; Toon, Owen B.; Hamill, Patrick

    1991-01-01

    The classical theory of homogeneous nucleation was used to calculate the freezing rate of sulfuric acid solution aerosols under stratospheric conditions. The freezing of stratospheric aerosols would be important for the nucleation of nitric acid trihydrate particles in the Arctic and Antarctic stratospheres. In addition, the rate of heterogeneous chemical reactions on stratospheric aerosols may be very sensitive to their state. The calculations indicate that homogeneous freezing nucleation of pure water ice in the stratospheric solution droplets would occur at temperatures below about 192 K. However, the physical properties of H2SO4 solution at such low temperatures are not well known, and it is possible that sulfuric acid aerosols will freeze out at temperatures ranging from about 180 to 195 K. It is also shown that the temperature at which the aerosols freeze is nearly independent of their size.

  15. Analysis of freezing in an eccentric annulus

    SciTech Connect

    Zhang, Y.; Faghri, A.

    1996-12-31

    Thermal energy storage systems are very important in the harnessing of periodical energy sources, such as solar energy. The phase change thermal energy storage system is the most promising since it can store and release a large amount of heat energy during the melting and freezing process. Freezing in an eccentric annulus is investigated numerically by using a temperature transforming model. Since the effect of the heat conduction along the circular direction on the growth of the freezing layer is very small, an analytical solution by employing integral approximate method is proposed. The freezing rate obtained by the analytical solution agreed very well with that of the numerical solution, although the analytical solution is much simpler than the numerical solution. The effects of the eccentric annulus geometric structure on the freezing process is also investigated.

  16. Bioinspired Design: Magnetic Freeze Casting

    NASA Astrophysics Data System (ADS)

    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.

  17. Depression and Osteoporosis

    MedlinePLUS

    ... More Information on Osteoporosis Citations Reprints Depression and Osteoporosis Order a free hardcopy En Español Introduction Depression ... see the NIMH booklet on Depression . What is osteoporosis? Osteoporosis is a disease that thins and weakens ...

  18. Depression and Diabetes

    MedlinePLUS

    ... More Information on Diabetes Citations Reprints Depression and Diabetes Order a free hardcopy En Español Introduction Depression ... see the NIMH booklet on Depression . What is diabetes? Diabetes is an illness that affects the way ...

  19. Depression and Multiple Sclerosis

    MedlinePLUS

    Depression - National Multiple Sclerosis Society Skip to navigation Skip to content Menu Navigation National Multiple Sclerosis Society ... Twitter Email Home Symptoms & Diagnosis MS Symptoms Depression Depression Share Smaller Text Larger Text Print In this ...

  20. Persistent depressive disorder

    MedlinePLUS

    PDD; Chronic depression; Depression - chronic ... The exact cause of persistent depressive disorder (PDD) is unknown. It tends to run in families. PDD occurs more often in women. Most people with PDD will also ...

  1. Freezing Out Early Dark Energy

    E-print Network

    Jannis Bielefeld; W. L. Kimmy Wu; Robert R. Caldwell; Olivier Dore

    2013-05-09

    A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops rapidly as if it were a relic species that freezes out, during which time the equation of state peaks at +1. Such an adjustment in the dark energy density, as it shifts from scaling to potential-domination, could be the signature of a trigger mechanism that helps explain the late-time cosmic acceleration. We show that the non-negligible dark energy density at early times, and the subsequent peak in the equation of state at the transition, leave an imprint on the cosmic microwave background anisotropy pattern and the rate of growth of large scale structure. The model introduces two new parameters, consisting of the present-day equation of state and the redshift of the freeze-out transition. A Monte Carlo Markov Chain analysis of a ten-dimensional parameter space is performed to compare the model with pre-Planck cosmic microwave background, large scale structure and supernova data and measurements of the Hubble constant. We find that the transition described by this model could have taken place as late as a redshift z~400. We explore the capability of future cosmic microwave background and weak lensing experiments to put tighter constraints on this model. The viability of this model may suggest new directions in dark-energy model building that address the coincidence problem.

  2. Effect of Freeze Drying from Dilute Solution on the Glass Transition Temperature of Polystyrene

    NASA Astrophysics Data System (ADS)

    Bernazzani, Paul; McKenna, Gregory; Simon, Sindee

    2003-03-01

    It is well known that the structural and dynamic properties of thin polymer films are often different from that in the bulk state. Of particular interest is the cause of the depression in glass transition temperature (Tg) in ultra-thin films. In previous work, the effects of freeze-drying from dilute solution on Tg were investigated by measuring the glass transition temperature of polystyrenes with various molecular weights. A reduction of Tg was found. In this work, using linear and cyclic polystyrenes, the mechanism of this depression is investigated by following the time-dependent recovery of the Tg depression as a function of temperature and confirming that entanglement concentration is not related to this effect.

  3. Monitoring the freeze-thaw process of soil with different moisture contents using piezoceramic transducers

    NASA Astrophysics Data System (ADS)

    Wang, Ruolin; Zhu, Daopei; Liu, Xiaoyan; Sima, Jun

    2015-05-01

    Water content plays an active and important role in the performance of the soil freeze-thaw cycle to form frozen soil mechanical properties. Monitoring the freeze-thaw cycle of soil with various types of soil with varied moisture content will provide a direct observation of the properties of soil in cold regions. This paper presents new findings from monitoring the freeze-thaw process of soil using a piezoceramic-based smart aggregate (SA). For comparison, clay soil and medium sand with different moisture contents were used to study the behavior of the soil under the freeze-thaw process. Two SAs were embedded in the soil specimens with a pre-determined distance between them, one as an actuator to generate a stress wave and the other as a sensor to detect the propagated wave. As the propagation of the emitted wave is sensitive to soil status and properties, it is possible to monitor the soil freeze-thaw process by interpreting the SA sensor signal. Based on the attenuation of the energy, a freeze-thaw status indicator was established to describe the freezing-thawing condition. Indicator values of soil specimens with different types and different levels of moisture in freeze-thaw cycles were studied. The test results indicate that the freezing duration in the freezing-thawing process varied for different types of soil and different initial moisture content of the soil. Soil with different particle sizes and moisture content will determine the frozen soil microstructure and its corresponding mechanical properties. Our results illustrate that if soil particle size is bigger, then the signal indicator is stronger; if the moisture content is higher for the same soil, then the signal indicator is stronger. The research presents an innovative method to investigate the freezing-thawing performance of soil and potentially points to a new method to study the variation of soil mechanical properties during the freezing-thawing process, which is a critical problem for infrastructure in cold regions.

  4. New particle dependant parameterizations of heterogeneous freezing processes.

    NASA Astrophysics Data System (ADS)

    Diehl, Karoline; Mitra, Subir K.

    2014-05-01

    For detailed investigations of cloud microphysical processes an adiabatic air parcel model with entrainment is used. It represents a spectral bin model which explicitly solves the microphysical equations. The initiation of the ice phase is parameterized and describes the effects of different types of ice nuclei (mineral dust, soot, biological particles) in immersion, contact, and deposition modes. As part of the research group INUIT (Ice Nuclei research UnIT), existing parameterizations have been modified for the present studies and new parameterizations have been developed mainly on the basis of the outcome of INUIT experiments. Deposition freezing in the model is dependant on the presence of dry particles and on ice supersaturation. The description of contact freezing combines the collision kernel of dry particles with the fraction of frozen drops as function of temperature and particle size. A new parameterization of immersion freezing has been coupled to the mass of insoluble particles contained in the drops using measured numbers of ice active sites per unit mass. Sensitivity studies have been performed with a convective temperature and dew point profile and with two dry aerosol particle number size distributions. Single and coupled freezing processes are studied with different types of ice nuclei (e.g., bacteria, illite, kaolinite, feldspar). The strength of convection is varied so that the simulated cloud reaches different levels of temperature. As a parameter to evaluate the results the ice water fraction is selected which is defined as the relation of the ice water content to the total water content. Ice water fractions between 0.1 and 0.9 represent mixed-phase clouds, larger than 0.9 ice clouds. The results indicate the sensitive parameters for the formation of mixed-phase and ice clouds are: 1. broad particle number size distribution with high number of small particles, 2. temperatures below -25°C, 3. specific mineral dust particles as ice nuclei such as illite or montmorillonite. Coupled cases of deposition and contact freezing show that they are hardly in competition because of differences in the preferred particle sizes. In the contact mode, small particles are less efficient for collisions as well as less efficient as ice nuclei so that these are available for deposition freezing. On the other hand, immersion freezing is the dominant process when it is coupled with deposition freezing. As it is initiated earlier the formed ice particles consume water vapor for growing. The competition of combined contact and immersion freezing leads to lower ice water contents because more ice particles are formed via the immersion mode. In general, ice clouds and mixed-phase clouds with high ice water fractions are not directly the result of primary ice formation but of secondary ice formation and growth of ice particles at the expense of liquid drops.

  5. Immersion freezing of different kinds of combustion ashes

    NASA Astrophysics Data System (ADS)

    Augustin-Bauditz, Stefanie; Grawe, Sarah; Hellner, Lisa; Wex, Heike; Pettersson, Jan B. C.; Stratmann, Frank

    2015-04-01

    Ice particles in the atmosphere influence both, weather and climate. Therefore it is important to know which kind of particles can act as ice nucleating particles (INP) under atmospheric conditions. In the last years, a lot of effort has been made to investigate the freezing abilities of natural INPs such as dusts and biological particles (Murray et al., 2012, Hoose and Möhler, 2012). However, there are only a few investigations concerning the ice nucleation ability of combustion ashes, which are the remains of fossil fuel and wood combustion and thus a possible source for anthropogenic INPs. Ash particles have similar compositions as mineral dust particles. However, the actual contribution of combustion ash particles to the atmospheric ice nucleation is rather unclear. A recent study by Umo et al. (2014) showed that combustion ashes could have a significant impact on the ice nucleation in clouds and thus should be the focus of further research. Ash particles can be lifted to the atmosphere by wind (bottom ashes) or directly during the combustion process (fly ashes). In the present study we investigated the freezing behavior of bottom ash particles which originated from wood as well as from coal. Additionally we investigated particles from fly ash from a coal-fired power plant. Particles were generated by dry dispersion and afterwards size selected with a differential mobility analyzer (DMA). The immersion freezing ability of the different ash particles was quantified utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS, Hartmann et al., 2011), where exactly one size segregated ash particle is immersed in a droplet. We found significant differences between the freezing abilities of the different ash types. Particles from wood bottom ashes initiate freezing at rather low temperatures near the homogenous freezing point (around -36°C). Particles from coal bottom ashes show significant higher ice nucleation abilities than the wood bottom ash, with observed freezing temperatures similar to those of clay minerals (around -30°C). The particles from the fly ash showed the best freezing ability, which was significantly higher than the freezing ability of the clay minerals but still not as good as that of K-feldspar. Hartmann, S., Niedermeier, D., Voigtländer, J., Clauss, T., Shaw, R. A., Wex, H., Kiselev, A., and Stratmann, F.: Atmos. Chem. Phys., 11, 1753-1767, doi:10.5194/acp-11-1753-2011, 2011. Hoose, C. and O. Möhler, Atmos. Chem. Phys., 12, 9817-9854, 2012. Murray, B. J., O'Sullivan, D., Atkinson, J. D. and Webb, M. E., Chem. Soc. Rev., 41, 6519-6554, 2012. Umo N. S., Murray B. J., Baeza-Romero M. T., Jones J. M., Lea-Langton A. R., Malkin T. L., O'Sullivan D., Plane J. M. C. and Williams A., Atmos. Chem. Phys. Discuss., 14, 28845-28883, 2014

  6. Transmission electron microscopy of thin sections of Drosophila: high-pressure freezing and freeze-substitution.

    PubMed

    McDonald, Kent L; Sharp, David J; Rickoll, Wayne

    2012-04-01

    The state of the art in fine-structure preservation for thin sectioning can be achieved by using fast-freezing technology followed by freeze substitution and embedding in resin. Samples prepared by high-pressure freezing are estimated to be "fixed" in 20-50 msec. Fast freezing also freezes every cell component regardless of its chemistry. Once frozen, tissues can be processed in a variety of ways before viewing in the electron microscope; here we describe only freeze substitution. In freeze substitution, cells are dehydrated at very low temperatures and cell water is replaced with organic solvent at -80°C to -90°C. At this temperature, large molecules such as proteins are immobilized, yet smaller molecules such as water (ice) can be dissolved and replaced with organic solvents, e.g., acetone. The ideal way to do freeze substitution is with a dedicated freeze-substitution device such as the Leica AFS2 system. These devices allow programming of the times and temperatures needed. Alternatively, if this equipment is not available, freeze substitution can still be performed using items commonly found around the laboratory, as is described here. This protocol is useful for preparing thin sections of Drosophila when the best possible preservation of ultrastructure and antigenicity is required. PMID:22474654

  7. Microbial analysis and survey test of gamma-irradiated freeze-dried fruits for patient's food

    NASA Astrophysics Data System (ADS)

    Park, Jae-Nam; Sung, Nak-Yun; Byun, Eui-Hong; Byun, Eui-Baek; Song, Beom-Seok; Kim, Jae-Hun; Lee, Kyung-A.; Son, Eun-Joo; Lyu, Eun-Soon

    2015-06-01

    This study examined the microbiological and organoleptic qualities of gamma-irradiated freeze-dried apples, pears, strawberries, pineapples, and grapes, and evaluated the organoleptic acceptability of the sterilized freeze-dried fruits for hospitalized patients. The freeze-dried fruits were gamma-irradiated at 0, 1, 2, 3, 4, 5, 10, 12, and 15 kGy, and their quality was evaluated. Microorganisms were not detected in apples after 1 kGy, in strawberries and pears after 4 kGy, in pineapples after 5 kGy, and in grapes after 12 kGy of gamma irradiation. The overall acceptance score, of the irradiated freeze-dried fruits on a 7-point scale at the sterilization doses was 5.5, 4.2, 4.0, 4.1, and 5.1 points for apples, strawberries, pears, pineapples, and grapes, respectively. The sensory survey of the hospitalized cancer patients (N=102) resulted in scores of 3.8, 3.7, 3.9, 3.9, and 3.7 on a 5-point scale for the gamma-irradiated freeze-dried apples, strawberries, pears, pineapples, and grapes, respectively. The results suggest that freeze-dried fruits can be sterilized with a dose of 5 kGy, except for grapes, which require a dose of 12 kGy, and that the organoleptic quality of the fruits is acceptable to immuno-compromised patients. However, to clarify the microbiological quality and safety of freeze-dried fruits should be verified by plating for both aerobic and anaerobic microorganisms.

  8. Freezing Characteristics of Droplet on a Cooled Wall

    NASA Astrophysics Data System (ADS)

    Horibe, Akihiko; Fukusako, Shouichiro; Yamada, Masahiko

    An experimental study has been performed to investigate the freezing characteristics of an aqueous binary solution droplet on a cooled wall. Pure water, ethylene-glycol aqueous solutions of 1to 10 mass%, and NaCl aqueous solutions of 1 to 15 mass% in concentration were adopted as the testing solutions. The droplet was frozen under a variety of cooling conditions such as wall temperature, air temperature, air velocity, and solute concentration in both the static atmosphere and the cold air flow. The observations on both the freezing characteristics and the morphologies of the droplet were extensively carried out. In addition, the inside flow of the droplets were observed. It was found that the morphology of the droplet on the cooled wall varied markedly depending on the solution, which appears to be mainly caused by the difference in the surface tension of the solution. On the other hand, under the conditions with a cold air flow, initial freezing point of the droplet was found to be mainly owing to the cooling rate between the cooled wall and the cold air.

  9. Chilled water coil freeze protection via internal drying

    SciTech Connect

    LaRocca, D.V.

    1997-12-01

    Winter lay-up for chilled water coils has been a problem for as long as there has been air conditioning. A frozen coil may be so seriously damaged that it must be replaced. Also, as the coil thaws, significant flooding of adjacent areas may result. Over the years, various methods of freeze protection have been used. These methods include using a glycol solution to lower the freezing point, blowing the coil clear with compressed air, or installing coils that incorporate freeze plugs in the coil design. Each of these methods has one or more significant drawbacks. A new approach, nicknamed ``The LaRocca Solution`` is a simple procedure. Air is blown continuously through the coils to ensure that they become completely dry and remain so. Instead of using a separate blower or air compressor to blow out the water, the supply fan itself is used. On most medium- and high-pressure HVAC systems, the static pressure produced by the supply fan is sufficient to overcome the internal resistance of the coil tubes. One simply configures the chilled water piping in a manner that permits the coils to be drained by gravity and then purged by the discharge of the fan. The fan does all the work.

  10. Sensitivity of liquid clouds to homogenous freezing parameterizations

    PubMed Central

    Herbert, Ross J; Murray, Benjamin J; Dobbie, Steven J; Koop, Thomas

    2015-01-01

    Water droplets in some clouds can supercool to temperatures where homogeneous ice nucleation becomes the dominant freezing mechanism. In many cloud resolving and mesoscale models, it is assumed that homogeneous ice nucleation in water droplets only occurs below some threshold temperature typically set at ?40°C. However, laboratory measurements show that there is a finite rate of nucleation at warmer temperatures. In this study we use a parcel model with detailed microphysics to show that cloud properties can be sensitive to homogeneous ice nucleation as warm as ?30°C. Thus, homogeneous ice nucleation may be more important for cloud development, precipitation rates, and key cloud radiative parameters than is often assumed. Furthermore, we show that cloud development is particularly sensitive to the temperature dependence of the nucleation rate. In order to better constrain the parameterization of homogeneous ice nucleation laboratory measurements are needed at both high (>?35°C) and low (Points Homogeneous freezing may be significant as warm as ?30°C Homogeneous freezing should not be represented by a threshold approximation There is a need for an improved parameterization of homogeneous ice nucleation PMID:26074652

  11. Exploring the Nature of Contact Freezing

    NASA Astrophysics Data System (ADS)

    Kiselev, A. A.; Hoffmann, N.; Duft, D.; Leisner, T.

    2012-12-01

    The freezing of supercooled water droplets upon contact with aerosol particles (contact nucleation of ice) is the least understood mechanism of ice formation in atmospheric clouds. Although experimental evidences suggest that some aerosols can be better IN in the contact than in the immersion mode (that is, triggering ice nucleation at higher temperature), no final explanation of this phenomena currently exists. On the other hand, the contact freezing is believed to be responsible for the enhanced rate of secondary ice formation occasionally observed in LIDAR measurements in the cold mixed phase clouds. Recently we have been able to show that the freezing of supercooled droplets electrodynamically levitated in the laminar flow containing mineral dust particles (kaolinite) is a process solely governed by a rate of collisions between the supercooled droplet and the aerosol particles. We have shown that the probability of droplet freezing on a single contact with aerosol particle may differ over an order of magnitude for kaolinite particles having different genesis and morphology. In this presentation we extend the study of contact nucleation of ice and compare the IN efficiency measured for DMA-selected kaolinite, illite and hematite particles. We show that the freezing probability increases towards unity as the temperature decreases and discuss the functional form of this temperature dependence. We explore the size dependence of the contact freezing probability and show that it scales with the surface area of the particles, thus resembling the immersion freezing behavior. However, for all minerals investigated so far, the contact freezing has been shown to dominate over immersion freezing on the short experimental time scales. Finally, based on the combined ESEM and electron microprobe analysis, we discuss the significance of particle morphology and variability of chemical composition on its IN efficiency in contact mode.

  12. Gullied Depression

    NASA Technical Reports Server (NTRS)

    2006-01-01

    26 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies formed in the wall of a depression located on the floor of Rabe Crater west of the giant impact basin, Hellas Planitia. Gullies such as these are common features on Mars, but the process by which they are formed is not fully understood. The debate centers on the role and source of fluids in the genesis of these features.

    Location near: 44.1oS, 325.9oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  13. Hot big bang or slow freeze?

    NASA Astrophysics Data System (ADS)

    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.

  14. Hot big bang or slow freeze?

    E-print Network

    C. Wetterich

    2014-05-23

    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.

  15. Simulations of Polar Stratospheric Clouds and Denitrification Using Laboratory Freezing Rates

    NASA Technical Reports Server (NTRS)

    Drdla, Katja; Tabazadeh, Azadeh; Gore, Warren J. (Technical Monitor)

    2001-01-01

    During the 1999-2000 Arctic winter, the SAGE (Stratospheric Aerosol and Gas Experiment) III Ozone Loss and Validation Experiment (SOLVE) provided evidence of widespread solid-phase polar stratospheric clouds (PSCs) accompanied by severe nitrification. Previous simulations have shown that a freezing process occurring at temperatures above the ice frost point is necessary to explain these observations. In this work, the nitric acid freezing rates measured by Salcedo et al. and discussed by Tabazadeh et al. have been examined. These freezing rates have been tested in winter-long microphysical simulations of the 1999-2000 Arctic vortex evolution in order to determine whether they can explain the observations. A range of cases have been explored, including whether the PSC particles are composed of nitric acid dihydrate or trihydrate, whether the freezing process is a bulk process or occurs only on the particle surfaces, and uncertainties in the derived freezing rates. Finally, the possibility that meteoritic debris enhances the freezing rate has also been examined. The results of these simulations have been compared with key PSC and denitrification measurements made by the SOLVE campaign. The cases that best reproduce the measurements will he highlighted, with a discussion of the implications for our understanding of PSCs.

  16. Evaluation of spin freezing versus conventional freezing as part of a continuous pharmaceutical freeze-drying concept for unit doses.

    PubMed

    De Meyer, L; Van Bockstal, P-J; Corver, J; Vervaet, C; Remon, J P; De Beer, T

    2015-12-30

    Spin-freezing as alternative freezing approach was evaluated as part of an innovative continuous pharmaceutical freeze-drying concept for unit doses. The aim of this paper was to compare the sublimation rate of spin-frozen vials versus traditionally frozen vials in a batch freeze-dryer, and its impact on total drying time. Five different formulations, each having a different dry cake resistance, were tested. After freezing, the traditionally frozen vials were placed on the shelves while the spin-frozen vials were placed in aluminum vial holders providing radial energy supply during drying. Different primary drying conditions and chamber pressures were evaluated. After 2h of primary drying, the amount of sublimed ice was determined in each vial. Each formulation was monitored in-line using NIR spectroscopy during drying to determine the sublimation endpoint and the influence of drying conditions upon total drying time. For all tested formulations and applied freeze-drying conditions, there was a significant higher sublimation rate in the spin-frozen vials. This can be explained by the larger product surface and the lower importance of product resistance because of the much thinner product layers in the spin frozen vials. The in-line NIR measurements allowed evaluating the influence of applied drying conditions on the drying trajectories. PMID:25981618

  17. Neuroimaging of Freezing of Gait.

    PubMed

    Fasano, Alfonso; Herman, Talia; Tessitore, Alessandro; Strafella, Antonio P; Bohnen, Nicolaas I

    2015-06-01

    Functional brain imaging techniques appear ideally suited to explore the pathophysiology of freezing of gait (FOG). In the last two decades, techniques based on magnetic resonance or nuclear medicine imaging have found a number of structural changes and functional disconnections between subcortical and cortical regions of the locomotor network in patients with FOG. FOG seems to be related in part to disruptions in the "executive-attention" network along with regional tissue loss including the premotor area, inferior frontal gyrus, precentral gyrus, the parietal and occipital areas involved in visuospatial functions of the right hemisphere. Several subcortical structures have been also involved in the etiology of FOG, principally the caudate nucleus and the locomotor centers in the brainstem. Maladaptive neural compensation may present transiently in the presence of acute conflicting motor, cognitive or emotional stimulus processing, thus causing acute network overload and resulting in episodic impairment of stepping.In this review we will summarize the state of the art of neuroimaging research for FOG. We will also discuss the limitations of current approaches and delineate the next steps of neuroimaging research to unravel the pathophysiology of this mysterious motor phenomenon. PMID:25757831

  18. Freeze concentration beats the heat

    SciTech Connect

    Rosen, J.

    1990-12-01

    This paper reports on freeze concentration (FC) which saves energy and money in packaging, shipping, and storing food products. FC---in contrast to existing heat-evaporation processes---retains volatile flavor and aroma compounds in food products so that no additives are required to restore the taste and smell of the original product. In recent tests on orange, grapefruit, and pineapple juices, reconstituted FC juices were found to be superior in taste to juices produced by evaporation and similar to the original pasteurized juices. The dairy industry, which is the largest user of energy for concentration in the food sector, is looking to FC for new products such as frozen concentrated milk as well as better use of the milk by-products of cheese production. The biggest potential for new FC applications is in those industries that consume large amounts of energy for separation processing, according to a 1987 report prepared for EPRI. In the food industry, this includes milk, vinegar, and beer producers. Potential applications also abound in the pulp and paper, pharmaceutical, chemical, and petroleum industries. FC separates substances via crystallization at substantial energy savings.

  19. Gluon mass and freezing of the QCD coupling

    E-print Network

    A. C. Aguilar; J. Papavassiliou

    2007-11-06

    Infrared finite solutions for the gluon propagator of pure QCD are obtained from the gauge-invariant non-linear Schwinger-Dyson equation formulated in the Feynman gauge of the background field method. These solutions may be fitted using a massive propagator, with the special characteristic that the effective mass employed drops asymptotically as the inverse square of the momentum transfer, in agreement with general operator-product expansion arguments. Due to the presence of the dynamical gluon mass the strong effective charge extracted from these solutions freezes at a finite value, giving rise to an infrared fixed point for QCD.

  20. Composition and freezing of aqueous H2SO4/HNO3 solutions under polar stratospheric conditions

    NASA Astrophysics Data System (ADS)

    Beyer, K. D.; Seago, S. W.; Chang, H. Y.; Molina, M. J.

    1994-05-01

    The results of laboratory investigations of the freezing behavior of aqueous acid solutions indicate that in the stratosphere H2SO4/H2O aerosol droplets would not freeze at temperatures above the ice frost point in the absence of HNO3; however, in the presence of typical levels of HNO3 liquid sulfuric acid aerosols take up significant amounts of HNO3 and H2O vapors and freeze much more readily. This is a consequence of the very rapid change in composition of the liquid droplets as the temperature drops to within two to three degrees of the equilibrium temperature at which HNO3 and H2O vapors would co-condense to form a liquid solution. In the high latitude stratosphere this HNO3/H2O ‘dew point’ is typically around 192-194 K at 100 mbar.

  1. Composition and freezing of aqueous H2SO4/HNO3 solutions under polar stratospheric conditions

    NASA Technical Reports Server (NTRS)

    Beyer, K. D.; Seago, S. W.; Chang, H. Y.; Molina, M. J.

    1994-01-01

    The results of laboratory investigations of the freezing behavior of aqueous acid solutions indicate that in the stratosphere H2SO/H2O aerosol droplets would not freeze at temperatures above the ice frost point in the absence of HNO3; however, in the presence of typical levels of HNO3 liquid sulfuric acid aerosols take up significant amounts of HNO3 and H2O vapors and freeze much more readily. This is a consequence of the very rapid change in composition of the liquid droplets as the temperature drops to within two to three degrees of the equilibrium temperature at which HNO3 and H2O vapors would co-condense to form a liquid solution. In the high latitude stratosphere this HNO3/H2O 'dew point' is typically around 192-194 K at 100 mbar.

  2. Doering 6/2004 Freezing Cell Lines

    E-print Network

    Doering, Tamara

    in the lab!!! Please freeze down any strain you or others might use in the future, whether that is a crypto melted) sample out on the plate. I like using a sterile needle to obtain the ice chips of sample

  3. Freeze-out Conditions from Lattice QCD

    E-print Network

    Swagato Mukherjee

    2012-11-29

    We describe a procedure for determination of freeze-out parameters of heavy-ion collisions through direct comparisons between experimentally measured higher order cumulants of charge fluctuations and first principle (lattice) QCD calculations.

  4. 23.11.2014bo Akademi Univ -Thermal and Flow Engineering Piispankatu 8, 20500 Turku 1/28 6. Food cooling and freezing

    E-print Network

    Zevenhoven, Ron

    crystals that destroy the texture which gives loss of juices during thawing; fast freezing gives growth of many small ice crystals. The respiration of fruits and vegetables after harvesting means production, consuming oxygen) during storage Water content is very important: Also, the (first) freezing point drops

  5. Continuous decoupling and freeze-out

    E-print Network

    Joern Knoll

    2009-02-13

    The decoupling and freeze-out of energetic nuclear collisions is analysed in terms of transparent semi-classical decoupling formulae. They provide a smooth transition and generalise frequently employed instantaneous freeze-out procedures. Simple relations between the damping width and the duration of the decoupling process are presented and the implications on various physical phenomena arising from the expansion and decay dynamics of the highly compressed hadronic matter generated in high energy nuclear collisions are discussed.

  6. Feedback from Freeze-out in Hydrodynamics

    E-print Network

    John J. Neumann; Boris Lavrenchuk; George Fai

    1996-12-09

    Most hydrodynamical calculations used in heavy-ion physics ignore the effect of freeze-out matter carrying energy and momentum away from the expanding fluid. In a simple one-dimensional model we compare calculated energy density and velocity profiles, with and without interaction between fluid-like and freeze-out parts of the system, in order to estimate the importance of this effect.

  7. Notes on the freezing of simple substances

    SciTech Connect

    Stishov, S. M.

    2006-08-15

    Experimental data on the freezing of argon and the helium isotopes at high pressures are analyzed. It is found that attractive forces in argon can be adequately described by the van der Waals mean field theory. An analogous approximation may also be applicable to helium, but this cannot be established conclusively because of quantum effects. However, an analysis of experimental results on the freezing of helium intuitively suggests that the solid-phase stability region is enlarged by quantum effects.

  8. Improved Approximation Algorithms for the Freeze-Tag Problem

    E-print Network

    Mitchell, Joseph S.B.

    Improved Approximation Algorithms for the Freeze-Tag Problem Esther M. Arkin Applied Math In the Freeze-Tag Problem, the objective is to awaken a set of "asleep" robots, starting with only one "awake resemblance to the children's game of freeze-tag, this problem has been called Freeze-Tag Problem (FTP

  9. A sledge microtome for high resolution subsampling of freeze cores

    E-print Network

    Patterson, Timothy

    NOTES A sledge microtome for high resolution subsampling of freeze cores Andrew L. Macumber · R microtome designed for the high-resolution subsampling of freeze cores. This inexpensive freeze events even in systems with low sedimentation rates. The freeze-core micro- tome is particularly useful

  10. Depression and osteoarthritis.

    PubMed

    Lin, Elizabeth H B

    2008-11-01

    Depression is significant among patients with arthritis and musculoskeletal illnesses. However, the impact of depression on osteoarthritis has not been extensively studied. This article highlights the close links between these 2 prevalent chronic conditions, and the associated individual and societal burden. Results from a large clinical trial of depressed older patients with arthritis showed that a focused, collaborative depression care intervention not only decreased depression but also improved arthritis-associated outcomes, such as pain severity and arthritis-related limitations in daily activities. Relative to patients given usual care, patients receiving intervention also reported better health status and higher quality of life. Analyses of the depression interventions uncovered a reciprocal interrelation between depression and pain. Higher severity of either depression or pain decreased the benefits of systematic depression treatment and was associated with worse pain and depression outcomes. Current approaches to management of depression and arthritis do not reflect readily-available evidence-based treatment. A pilot study using a combined approach to address both depression and pain problems among elderly patients with depression and osteoarthritis suggested that benefits for depression, pain, and functional outcomes are strengthened by providing both pain and depression care management. An integrated depression and pain program using evidenced-based pharmacologic and nonpharmacologic treatments is needed to achieve optimal depression and pain outcomes. Currently, a randomized trial is under way to evaluate effectiveness of a combined pain and depression intervention using pharmacologic and nonpharmacologic therapies. Key intervention components in these 2 innovative and integrated depression and pain programs can guide clinicians to treat both depression and pain with more focus and intensity. PMID:18954588

  11. [Fatigue and depression].

    PubMed

    Hell, Daniel

    2015-04-22

    Fatigue is characterised in an overview of the literature as a specific phenomenon of depression. Its differential diagnosis is discussed. Distinctions and correspondences to burnout are elaborated. Fatigue is not an obligatory symptom of depressive episodes, although it can contribute to depressive developments. The importance of fatigue in depressive episodes and its therapy is shown with the help of a circular model of depression. PMID:26072598

  12. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.

    2008-01-01

    Spacecraft radiators are sized for their maximum heat load in their warmest thermal environment, but must operate at reduced heat loads and in colder environments. For systems where the radiator environment can be colder than the working fluid freezing temperature, radiator freezing becomes an issue. Radiator freezing has not been a major issue for the Space Shuttle and the International Space Station (ISS) active thermal control systems (ATCSs) because they operate in environments that are warm relative to the freezing point of their external coolants (Freon-21 and ammonia, respectively). For a vehicle that lands at the Lunar South Pole, the design thermal environment is 215K, but the radiator working fluid must also be kept from freezing during the 0 K sink of transit. A radiator bypass flow control design such as those used on the Space Shuttle and ISS requires more than 30% of the design heat load to avoid radiator freezing during transit - even with a very low freezing point working fluid. By changing the traditional ATCS architecture to include a regenerating heat exchanger inboard of the radiator and by using a regenerator bypass flow control valve to maintain system setpoint, the required minimum heat load can be reduced by more than half. This gives the spacecraft much more flexibility in design and operation. The present work describes the regenerator bypass ATCS setpoint control methodology. It includes analytical results comparing the performance of this system to the traditional radiator bypass system. Finally, a summary of the advantages of the regenerator bypass system are presented.

  13. The WAG/Rij strain: a genetic animal model of absence epilepsy with comorbidity of depression [corrected].

    PubMed

    Sarkisova, Karine; van Luijtelaar, Gilles

    2011-06-01

    A great number of clinical observations show a relationship between epilepsy and depression. Idiopathic generalized epilepsy, including absence epilepsy, has a genetic basis. The review provides evidence that WAG/Rij rats can be regarded as a valid genetic animal model of absence epilepsy with comorbidity of depression. WAG/Rij rats, originally developed as an animal model of human absence epilepsy, share many EEG and behavioral characteristics resembling absence epilepsy in humans, including the similarity of action of various antiepileptic drugs. Behavioral studies indicate that WAG/Rij rats exhibit depression-like symptoms: decreased investigative activity in the open field test, increased immobility in the forced swimming test, and decreased sucrose consumption and preference (anhedonia). In addition, WAG/Rij rats adopt passive strategies in stressful situations, express some cognitive disturbances (reduced long-term memory), helplessness, and submissiveness, inability to make choice and overcome obstacles, which are typical for depressed patients. Elevated anxiety is not a characteristic (specific) feature of WAG/Rij rats; it is a characteristic for only a sub-strain of WAG/Rij rats susceptible to audiogenic seizures. Interestingly, WAG/Rij rats display a hyper-response to amphetamine similar to anhedonic depressed patients. WAG/Rij rats are sensitive only to chronic, but not acute, antidepressant treatments, suggesting that WAG/Rij rats fulfill a criterion of predictive validity for a putative animal model of depression. However, more and different antidepressant drugs still await evaluation. Depression-like behavioral symptoms in WAG/Rij rats are evident at baseline conditions, not exclusively after stress. Experiments with foot-shock stress do not point towards higher stress sensitivity at both behavioral and hormonal levels. However, freezing behavior (coping deficits) and blunted response of 5HT in the frontal cortex to uncontrollable sound stress, increased c-fos expression in the terminal regions of the meso-cortico-limbic brain systems and greater DA response of the mesolimbic system to forced swim stress suggest that WAG/Rij rats are vulnerable to some, but not to all types of stressors. We propose that genetic absence epileptic WAG/Rij rats have behavioral depression-like symptoms, are vulnerable to stress and might represent a model of chronic low-grade depression (dysthymia). Both 5HT and DAergic abnormalities detected in the brain of WAG/Rij rats are involved in modulation of vulnerability to stress and provocation of behavioral depression-like symptoms. The same neurotransmitter systems modulate SWDs as well. Recent studies suggest that the occurrence and repetition of absence seizures are a precipitant of depression-like behavior. Whether the neurochemical changes are primary to depression-like behavioral alterations remains to be determined. In conclusion, the WAG/Rij rats can be considered as a genetic animal model for absence epilepsy with comorbidity of dysthymia. This model can be used to investigate etiology, pathogenic mechanisms and treatment of a psychiatric comorbidity, such as depression in absence epilepsy, to reveal putative genes contributing to comorbid depressive disorder, and to screen novel psychotropic drugs with a selective and/or complex (dual) action on both pathologies. PMID:21093520

  14. Preschool Depression: The Importance of Identification of Depression Early in Development

    PubMed Central

    Luby, Joan L.

    2010-01-01

    The empirical finding that school-aged children could suffer clinical depression refuted the widely held assumption that this age group would be too developmentally immature to experience depressive symptoms. Currently childhood depression is a well-recognized and widely treated clinical disorder. Following more recent developmental findings emphasizing the emotional sophistication of very young children, scientific studies have demonstrated that depression can arise early in life, during the preschool period of development. Preschool depression is characterized by typical symptoms of depression such as anhedonia; changes in sleep, appetite, and activity level; and excessive guilt. Further, longitudinal continuity of preschool depression into school age has been established, suggesting that preschool depression is an early manifestation of the later childhood disorder. Based on the known efficacy of early developmental intervention in a number of domains and disorders related to the greater neuroplasticity of the brain earlier rather than later in childhood, it is important to identify depression at the earliest possible point. Early intervention strategies for preschool depression that focus on enhancing emotional development are currently being tested. PMID:21969769

  15. Coincidence probability as a measure of the average phase-space density at freeze-out

    E-print Network

    A. Bialas; W. Czyz; K. Zalewski

    2006-02-08

    It is pointed out that the average semi-inclusive particle phase-space density at freeze-out can be determined from the coincidence probability of the events observed in multiparticle production. The method of measurement is described and its accuracy examined.

  16. Motor Imagery in Unipolar Major Depression

    PubMed Central

    Bennabi, Djamila; Monnin, Julie; Haffen, Emmanuel; Carvalho, Nicolas; Vandel, Pierre; Pozzo, Thierry; Papaxanthis, Charalambos

    2014-01-01

    Background: Motor imagery is a potential tool to investigate action representation, as it can provide insights into the processes of action planning and preparation. Recent studies suggest that depressed patients present specific impairment in mental rotation. The present study was designed to investigate the influence of unipolar depression on motor imagery ability. Methods: Fourteen right-handed patients meeting DSM-IV criteria for unipolar depression were compared to 14 matched healthy controls. Imagery ability was accessed by the timing correspondence between executed and imagined movements during a pointing task, involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). Results: Compared to controls, depressed patients showed marked motor slowing on both actual and imagined movements. Furthermore, we observed greater temporal discrepancies between actual and mental movements in depressed patients than in healthy controls. Lastly, depressed patients modulated, to some extent, mental movement durations according to the difficulty of the task, but this modulation was not as strong as that of healthy subjects. Conclusion: These results suggest that unipolar depression significantly affects the higher stages of action planning and point out a selective decline of motor prediction. PMID:25538580

  17. Freeze Tolerance of Nine Zoysiagrass Cultivars Using Natural Cold Acclimation and Freeze Chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter hardiness of zoysiagrass (Zoysia spp.) cultivars is an important attribute throughout the biogeographical transition zone, thus the inability to withstand freezing temperatures may limit the use of these cultivars. The objective of this research was to determine the freeze tolerance (LT50) of...

  18. The equilibrated state of freezing as a basis for distinguishing lethal stresses of freezing in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A model for coordination of stresses that limit winterhardiness in plants based on the thermodynamic equilibrated state of freezing and melting provides a rational basis for distinction of freeze-induced energies which can stress and injure living organisms in various ways. The departure from equili...

  19. Freeze drying for morphological control of inter-penetrating polymer networks

    NASA Technical Reports Server (NTRS)

    Hansen, Marion G.; Pater, Ruth H.

    1990-01-01

    The intrinsic brittleness of BMI resins can be reduced through the creation of an interpenetrating network (IPN) of BMI with a reactive-encapped thermoplastic, such as the presently considered polyimidesulfone, PISO2. The PISO2 and BMI were dissolved in a common solvent, which was then removed from the constituents by freeze drying; in an alternative method, an IPN was formed through dissolution of the constituent in a common solvent with either high or low melting point, followed by evaporative removal of the solvent. The effectiveness of the freeze-drying approach for morphological control is evaluated.

  20. Freeze-drying of lactic acid bacteria.

    PubMed

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  1. Droplet coalescence and freezing on hydrophilic, hydrophobic, and biphilic surfaces

    NASA Astrophysics Data System (ADS)

    Van Dyke, Alexander S.; Collard, Diane; Derby, Melanie M.; Betz, Amy Rachel

    2015-10-01

    Frost and ice formation can have severe negative consequences, such as aircraft safety and reliability. At atmospheric pressure, water heterogeneously condenses and then freezes at low temperatures. To alter this freezing process, this research examines the effects of biphilic surfaces (surfaces which combine hydrophilic and hydrophobic regions) on heterogeneous water nucleation, growth, and freezing. Silicon wafers were coated with a self-assembled monolayer and patterned to create biphilic surfaces. Samples were placed on a freezing stage in an environmental chamber at atmospheric pressure, at a temperature of 295 K, and relative humidities of 30%, 60%, and 75%. Biphilic surfaces had a significant effect on droplet dynamics and freezing behavior. The addition of biphilic patterns decreased the temperature required for freezing by 6 K. Biphilic surfaces also changed the size and number of droplets on a surface at freezing and delayed the time required for a surface to freeze. The main mechanism affecting freezing characteristics was the coalescence behavior.

  2. Freezing-thawing action in the deterioration of the stones of Chambord Castle

    NASA Astrophysics Data System (ADS)

    Alomari, Asaad; Brunetaud, Xavier; Beck, Kevin; Al-Mukhtar, Muzahim

    2013-04-01

    Limestone is very common in architecture (monuments and cultural heritage buildings) and used in the sculptures. The soft and porous limestone soaks up water and show weathering patterns and forms: alveolar weathering, granular disintegration, efflorescences. Freezing-thawing actions can be considered as one of the processes that contribute in the deterioration of stones located in the "cold regions" characterized with air temperatures below freezing point temperature. The amount of water within the pore space of the stones is a crucial factor of the decay. The experimental work presented in this paper is a part of a research program that aims to study the mechanisms that lead to the degradation of stone building materials due to the variation of climatic conditions. The analysis of the meteorological data of the field around the castle of Chambord shows the magnitude of temperature variations and the frequency of freezing-thawing cycles. The critical degrees of saturation at which the stone start to deteriorate after treatment with freezing-thawing cycles were examined in the tests conducted. The study concerns two porous limestone used in the construction and conservation of Chambord castle; highly porous Tuffeau stone having a total porosity of about 48 %, and medium porous Richemont stone with a total porosity of 27 %. Richemont stone has been used as a substitute stone of the degraded Tuffeau stone on the castle. The main physical properties, total porosity, apparent dry density and skeleton density and sound velocity for mechanical properties were measured for the stone samples before and during freezing-thawing cycles. ASTM (D5312-04) procedure was applied in the freezing-thawing tests. Tuffeau and Richmond samples were prepared at nine different degrees of saturations; 0, 20, 40, 70, 80, 85, 90, 95 and 100%, and properties were measured after different freezing-thawing cycles conditions; 2, 4, 8, 12, 16, 20, 30 and 50 cycles. The results of these tests show that when the degree of saturation exceeds 80-85%, freeze-thaw damage is inevitable even for a very few freeze-thaw cycles. Moreover, results indicate that the two studied stones have similar critical degree of saturation of about 85 %. This can be attributed to the similar percentage of macro-pores in the two tested stones. Finally, the critical degree of saturation was not changed after increasing the number of freezing-thawing cycles, thus the critical degree of saturation can be considered as a stone property.

  3. Soil salinity increases survival of freezing in the enchytraeid Enchytraeus albidus.

    PubMed

    Silva, A L Patrício; Holmstrup, M; Kostal, V; Amorim, M J B

    2013-07-15

    Enchytraeus albidus is a freeze-tolerant enchytraeid found in diverse habitats, ranging from supralittoral to terrestrial and spanning temperate to arctic regions. Its freeze tolerance is well known but the effect of salinity in this strategy is still poorly understood. We therefore studied the combined effect of salinity (0, 15, 35, 50‰ NaCl) and sub-zero temperatures (-5, -14, -20°C) on the freeze tolerance of E. albidus collected from two distinct geographical regions (Greenland and Germany). A full factorial design was used to study survival, and physiological and biochemical end points. The effect of salinity on the reproduction of German E. albidus was also assessed. Exposure for 48 h to saline soils prior to cold exposure triggered an increase in osmolality and decrease in water content. Worms exposed to saline soils had an improved survival of freezing compared to worms frozen in non-saline soils, particularly at -20°C (survival more than doubled). Differential scanning calorimetry measurements showed that the fraction of water frozen at -5 and -14°C was lower in worms exposed to 35‰ NaCl than in control worms. The lowering of ice content by exposure to saline soils was probably the main explanation for the better freeze survival in saline-exposed worms. Glucose increased with decreasing temperature, but was lower in saline than in non-saline soils. Thus, glucose accumulation patterns did not explain differences in freeze survival. Overall, the physiological responses to freezing of E. albidus from Greenland and Germany were similar after exposure to saline soils. Soil salinity up to 30‰ improved reproduction by a factor of ca. 10. PMID:23531829

  4. Do You Have Major Depression?

    MedlinePLUS

    ... of this page please turn Javascript on. Feature: Depression Do You Have Major Depression? Past Issues / Fall 2009 Table of Contents Simple ... member may have major depression. —NIMH Types of Depression Just like other illnesses, such as heart disease, ...

  5. Depression and HIV/AIDS

    MedlinePLUS

    ... For More Information on HIV/AIDS Citations Reprints Depression and HIV/AIDS Order a free hardcopy En ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ...

  6. Major Depression Among Adults

    MedlinePLUS

    ... on NIMH’s depression page . NEXT Statistical Methods and Measurement Caveats Diagnostic Assessment: Modules related to major depressive ... NSDUH weighting includes non-response adjustments to reduce bias, these adjustments may not fully account for differential ...

  7. Depression in Older Adults

    ERIC Educational Resources Information Center

    Stickle, Fred; Onedera, Jill D.

    2006-01-01

    The purpose of this article is to address selected aspects of depression in older adults. Specifically, symptoms, risk factors, diagnosis, and interventions for depression in older adults are reviewed.

  8. Managing your depression - teens

    MedlinePLUS

    ... Jansen KL, Cloy JA. Treatment of childhood and adolescent depression. Am Fam Physician . 2012;86:442-448. PMID ... Services Task Force. Screening and treatment for major depressive ... Services Task Force Recommendation Statement. Pediatrics . ...

  9. Postpartum Depression Action Plan

    MedlinePLUS

    MENU Return to Web version Postpartum Depression | Postpartum Depression Action Plan Patient __________________________ Physician/NP/PA __________________ Clinic ____________________________ Phone Number ____________________ Choose one area and add other areas as you begin to ...

  10. Depression - stopping your medicines

    MedlinePLUS

    ... prescription medicines you may take to help with depression, anxiety, or pain. Like any medicine, there are reasons ... Depression or anxiety might not come back right away when you stop taking the medicine, but it may come ...

  11. Depression and Heart Disease

    MedlinePLUS

    ... Information on Heart Disease Citations Reprints Depression and Heart Disease Order a free hardcopy En Español Introduction ... see the NIMH booklet on Depression . What is heart disease? Heart disease refers to a number of ...

  12. Depression and cardiovascular disease.

    PubMed

    Bradley, Steven M; Rumsfeld, John S

    2015-10-01

    There is a wealth of evidence linking depression to increased risk for cardiovascular disease (CVD) and worse outcomes among patients with known CVD. In addition, there are safe and effective treatments for depression. Despite this, depression remains under-recognized and undertreated in patients at risk for or living with CVD. In this review, we first summarize the evidence linking depression to increased risk of CVD and worse patient outcomes. We then review the mechanisms by which depression may contribute to cardiovascular risk and poor cardiovascular outcomes. We then summarize prior studies of depression treatment on cardiovascular outcomes. Finally, we offer guidance in the identification and management of depression among CVD populations. Given that 1 in 4 CVD patients has concurrent depression, application of these best-practices will assist providers in achieving optimal outcomes for their CVD patients. PMID:25850976

  13. Genetic biomarkers of depression

    PubMed Central

    Tamatam, Anand; Khanum, Farhath; Bawa, Amarinder Singh

    2012-01-01

    Depression is a term that has been used to describe a variety of ailments, ranging from minor to incapacitating. Clinically significant depression, termed as major depression, is a serious condition characterized not only by depressed mood but also by a cluster of somatic, cognitive, and motivational symptoms. Significant research efforts are aimed to understand the neurobiological as well as psychiatric disorders, and the evaluation of treatment of these disorders is still based solely on the assessment of symptoms. In order to identify the biological markers for depression, we have focused on gathering information on different factors responsible for depression including stress, genetic variations, neurotransmitters, and cytokines and chemokines previously suggested to be involved in the pathophysiology of depression. The present review illustrates the potential of biomarker profiling for psychiatric disorders, when conducted in large collections. The review highlighted the biomarker signatures for depression, warranting further investigation. PMID:22754217

  14. Depression - older adults

    MedlinePLUS

    ... these steps do not help, medicines to treat depression and talk therapy often help. Doctors often prescribe lower doses of antidepressants to older people, and increase the dose more slowly ... depression at home, you should: Exercise regularly, if your ...

  15. Screening for Depression

    MedlinePLUS

    ... be used without permission. Education Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/Disorders Related ... wellness for people who live with depression and bipolar disorder. Because DBSA was created for and is led ...

  16. Depression and Suicide Risk

    MedlinePLUS

    ... A.C. (2007). NEJM — Expanding the Black Box — Depression, Antidepressants, and the Risk of Suicide. New England Journal ... A.C. (2007). NEJM — Expanding the Black Box — Depression, Antidepressants, and the Risk of Suicide. New England Journal ...

  17. Freeze verification: time for a fresh approach

    SciTech Connect

    Paine, C.

    1983-01-01

    The administration's claim that some elements of a comprehensive nuclear freeze are unverifiable does not specify the nature of those elements and whether they represent a real threat to national security if we trusted the USSR to comply. The author contends that clandestine development of new weapons will have little strategic effect since both sides already have total destructive power. The risks of noncompliance are largely political and less than the risks of continued arms buildup. Since the USSR would also want the US to be bound by freeze terms, deterrence would come from mutual benefit. Hardliners argue that cheating is easier in a closed society; that our democracy would tend to relax and the USSR would move ahead with its plans for world domination. The author argues that, over time, a freeze would diminish Soviet confidence in its nuclear war fighting capabilities and that adequate verification is possible with monitoring and warning arrangements. (DCK)

  18. Directional freezing for large volume cryopreservation.

    PubMed

    Saragusty, Joseph

    2015-01-01

    Cryopreservation is currently the method of choice when it comes to long-term preservation of viable biological samples. The process, and consequently the volume of the sample, however, is limited by the ability to achieve homogenous and efficient heat removal. When this cannot be properly managed, ice crystals will grow uncontrollably resulting in extensive damage to the cryopreserved cells or tissues. Directional freezing is a technique that can be used to precisely control heat dissipation and ice crystal growth and morphology even when freezing large volumes. The technique has been used over the years to cryopreserve spermatozoa, oocytes, embryos, tissue slices and whole organs from a wide variety of domestic and wild species. In this chapter a protocol for directional freezing of spermatozoa is described and its benefits and shortcomings are discussed. PMID:25428019

  19. Melting and freezing of argon in a granular packing of linear mesopore arrays

    E-print Network

    Christof Schaefer; Tommy Hofmann; Dirk Wallacher; Patrick Huber; Klaus Knorr

    2008-03-29

    Freezing and melting of Ar condensed in a granular packing of template-grown arrays of linear mesopores (SBA-15, mean pore diameter 8 nanometer) has been studied by specific heat measurements C as a function of fractional filling of the pores. While interfacial melting leads to a single melting peak in C, homogeneous and heterogeneous freezing along with a delayering transition for partial fillings of the pores result in a complex freezing mechanism explainable only by a consideration of regular adsorption sites (in the cylindrical mesopores) and irregular adsorption sites (in niches of the rough external surfaces of the grains, and at points of mutual contact of the powder grains). The tensile pressure release upon reaching bulk liquid/vapor coexistence quantitatively accounts for an upward shift of the melting/freeezing temperature observed while overfilling the mesopores.

  20. Method of treating depression

    DOEpatents

    Henn, Fritz (East Patchogue, NY)

    2012-01-24

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  1. Method of treating depression

    DOEpatents

    Henn, Fritz

    2013-04-09

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  2. Unitarity constraints on asymmetric freeze-in

    E-print Network

    Anson Hook

    2011-08-30

    This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order.

  3. Stratospheric Polar Freezing Belt Causes Denitrification

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Jensen, E. J.; Toon, O. B.; Drdla, K.; Schoeberl, M. R.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    Trajectory cloud model calculations are presented to show that homogeneous freezing of nitric acid hydrates can produce a polar freezing belt in both hemispheres that can cause denitrification. While hydrate cloud microphysical properties are similar over both poles, the shorter persistence of clouds in the Arctic prevents the depth of the denitrified layers from growing beyond a few kilometers. The 1999-2000 Arctic winter is unique in showing a distinct denitrification profile with a depth of approx. 4.5 km that is nearly half as deep as that computed for a typical Antarctic winter.

  4. Infrared Thermography for Monitoring of Freeze-Drying Processes: Instrumental Developments and Preliminary Results

    PubMed Central

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-01-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from ?40°C to 25°C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5°C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8°C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13°C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10°C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. © 2014 European Union 103:2088–2097, 2014 PMID:24902839

  5. Freeze-out conditions for production of resonances, hadronic molecules, and light nuclei

    E-print Network

    Cho, Sungtae; Lee, Su Houng

    2015-01-01

    We investigate the freeze-out conditions of a particle in an expanding system of interacting particles in order to understand the productions of resonances, hadronic molecules and light nuclei in heavy ion collisions. Applying the kinetic freeze-out condition with explicit hydrodynamic calculations for the expanding hadronic phase to the daughter particles of $K^*$ mesons, we find that the larger suppression of the yield ratio of $K^*/K$ at LHC than at RHIC compared to the expectations from the statistical hadronization model based on chemical freeze-out parameters reflects the lower kinetic freeze-out temperature at LHC than at RHIC. Furthermore, we point out that for the light nuclei or hadronic molecules that are bound, the yields are affected by the freeze-out condition of the respective particle in the hadronic matter, which leads to the observation that the deuteron production yields are independent of the size of deuteron, and depend only on the number of ground state constituents.

  6. Freeze-out conditions for production of resonances, hadronic molecules, and light nuclei

    E-print Network

    Sungtae Cho; Taesoo Song; Su Houng Lee

    2015-11-25

    We investigate the freeze-out conditions of a particle in an expanding system of interacting particles in order to understand the productions of resonances, hadronic molecules and light nuclei in heavy ion collisions. Applying the kinetic freeze-out condition with explicit hydrodynamic calculations for the expanding hadronic phase to the daughter particles of $K^*$ mesons, we find that the larger suppression of the yield ratio of $K^*/K$ at LHC than at RHIC compared to the expectations from the statistical hadronization model based on chemical freeze-out parameters reflects the lower kinetic freeze-out temperature at LHC than at RHIC. Furthermore, we point out that for the light nuclei or hadronic molecules that are bound, the yields are affected by the freeze-out condition of the respective particle in the hadronic matter, which leads to the observation that the deuteron production yields are independent of the size of deuteron, and depend only on the number of ground state constituents.

  7. Heart disease and depression

    MedlinePLUS

    Heart disease and depression often go hand-in-hand. You are are more likely to feel sad or depressed after a heart attack ... heart disease. The good news is that treating depression may help improve both your mental and physical ...

  8. Prevention of Depression.

    ERIC Educational Resources Information Center

    Compas, Bruce E.; Connor, Jennifer; Wadsworth, Martha

    Substantial numbers of children and adolescents experience symptoms of sadness, dysphoria, and other characteristics associated with depression. The nature of depression in children and adolescents has presented challenges in identification and definition. This chapter reviews research on depression in children and adolescents. Three current…

  9. Importance of Depression in Diabetes.

    ERIC Educational Resources Information Center

    Lustman, Patrick J.; Clouse, Ray E.; Anderson, Ryan J.

    Depression doubles the likelihood of comorbid depression, which presents as major depression in 11% and subsyndromal depression in 31% of patients with the medical illness. The course of depression is chronic, and afflicted patients suffer an average of one episode annually. Depression has unique importance in diabetes because of its association…

  10. Freezing cleans food processing wastewater

    SciTech Connect

    Not Available

    1998-01-01

    Snowfluent is a technology which atomizes wastewater effluent and sprays it into the air as ice crystals at cold temperatures. It has been found effective in treating municipal sewage and food processing wastes. This bulletin reviews pilot- and production-scale studies conducted at an Alberta malt producer to test whether the Snowfluent process has further applications for the treatment of food processing wastes. The study was designed to determine the percentage of nutrients removed by the technology, the point at which contaminants are reduced, the effect of the process on the shallow water table, and the health risk to operators involved.

  11. Nucleation Pathways For Freezing Of Two Grades Of Zirconium

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Rulison, Aaron; Bayuzick, Robert; Hofmeister, William; Morton, Craig

    1996-01-01

    Report discusses classical nucleation theory of freezing and describes experimental study of nucleation mechanisms that predominate during freezing of spherical specimens of initially molten zirconium levitated electrostatically in vacuum.

  12. Canalization of freeze tolerance in an alpine grasshopper.

    PubMed

    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 1year 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. PMID:26210007

  13. Liquid Freezing Dynamics on Hydrophobic and Superhydrophobic Surfaces

    E-print Network

    Miljkovic, Nenad

    False color environmental scanning electron microscope (ESEM) images of water freezing on smooth (?e ? 120°) and nanostructured (l ~ 50 nm, ?e ? 170 - 180°) hydrophobic surfaces are presented. To obtain the freezing dynamics ...

  14. Managing damaging freeze events in Louisiana sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposure of sugarcane to damaging frosts occurs in approximately 25% of the sugarcane producing countries of the world, but is most frequent on the mainland of the United States, especially in the state of Louisiana. The frequent winter freezes that occur in the sugarcane areas of Louisiana have fo...

  15. Unitarity Constraints on Asymmetric Freeze-In

    SciTech Connect

    Hook, Anson; /SLAC

    2011-08-15

    This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order. This note has shown that if two sectors are in thermal equilibrium with themselves, but not with each other, then the leading effect transferring conserved quantities between the two sectors is of order the the weak coupling connecting them to the third power. When freeze-in is used to produce a net baryon number density, the leading order effect comes from {Omicron}({lambda}{sup 3}) diagrams where the intermediate state that goes on-shell has a different visible baryon number than the final state visible baryon number. Models in which the correct baryon number is generated with freeze-in as the dominant source of abundance, typically require {lambda} {approx}> 10{sup -6} and m{sub bath} {approx}> TeV. m{sub bath} is the mass of the visible particle which communicates with the hidden sector. The lower window is potentially observable at the LHC.

  16. Freeze Crystallization Processes: Efficiency by Flexibility 

    E-print Network

    Heist, J. A.; Barron, T. S.

    1983-01-01

    change is required only once in freeze processes, as opposed to the high reflux ratios needed in most distillation separations. 2) The latent heat of fusion is less than the heat of vaporization, and the process operates at a lower temperature, so...

  17. FREEZE-FRAME: Fast Action Stress Relief.

    ERIC Educational Resources Information Center

    Childre, Doc Lew

    Recent scientific research has proven that we can, not only manage our stress, we can even prevent it. Ways to achieve stress management are presented in this book. It details a method called FREEZE-FRAME, a process in which individuals mentally stop the chaos that surrounds them and then calmly contemplate their situation. The text opens with an…

  18. Definition of Hydrologic Response Units in Depression Plagued Digital Elevation Models

    NASA Astrophysics Data System (ADS)

    Lindsay, J. B.; Creed, I. F.

    2002-12-01

    Definition of hydrologic response units using digital elevation models (DEMs) is sensitive to the occurrence of topographic depressions. Real depressions can be important to the hydrology and biogeochemistry a catchment, often coinciding with areas of surface saturation. Artifact depressions, in contrast, result in digital "black holes", artificially truncating the hydrologic flow lengths and altering hydrologic flow directions, parameters that are often used in defining hydrologic response units. Artifact depressions must be removed from DEMs prior to definition of hydrologic response units. Depression filling or depression trenching techniques can be used to remove these artifacts. Depression trenching methods are often considered more appropriate because they preserve the topographic variability within a depression thus avoiding the creation of spurious flat areas. Current trenching algorithms are relatively slow and unable to process very large or noisy DEMs. A new trenching algorithm that overcomes these limitations is described. The algorithm does not require finding depression catchments or outlets, nor does it need special handling for nested depressions. Therefore, artifacts can be removed from large or noisy DEMs efficiently, while minimizing the number of grid elevations requiring modification. The resulting trench is a monotonically descending path starting from the lowest point in a depression, passing through the depression's outlet, and ending at a point of lower elevation outside the depression. The importance of removing artifact depressions is demonstrated by showing hydrologic response units both before and after the removal of artifact depressions from the DEM.

  19. 23 CFR 658.23 - LCV freeze; cargo-carrying unit freeze.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS § 658.23 LCV freeze... and pavement design characteristics of the alternate route should be equivalent to those of...

  20. 23 CFR 658.23 - LCV freeze; cargo-carrying unit freeze.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS § 658.23 LCV freeze... and pavement design characteristics of the alternate route should be equivalent to those of...

  1. 23 CFR 658.23 - LCV freeze; cargo-carrying unit freeze.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS § 658.23 LCV freeze... and pavement design characteristics of the alternate route should be equivalent to those of...

  2. 23 CFR 658.23 - LCV freeze; cargo-carrying unit freeze.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS § 658.23 LCV freeze... and pavement design characteristics of the alternate route should be equivalent to those of...

  3. 23 CFR 658.23 - LCV freeze; cargo-carrying unit freeze.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS § 658.23 LCV freeze... and pavement design characteristics of the alternate route should be equivalent to those of...

  4. Exact theory of freeze out

    E-print Network

    Mirco Cannoni

    2015-03-05

    We show that the standard theory of thermal production and chemical decoupling of WIMPs is incomplete. The hypothesis that WIMPs are produced and decouple from a thermal bath implies that the rate equation the bath particles interacting with the WIMPs is an algebraic equation that constraints the actual WIMPs abundance to have a precise analytical form down to the temperature $x_\\ast=m_\\chi /T_\\ast$. The point $x_\\ast$, which coincides with the stationary point of the equation for the quantity $\\Delta= Y-Y_0$, is where the maximum departure of the WIMPs abundance $Y$ from the thermal value $Y_0$ is reached. For each mass $m_\\chi$ and total annihilation cross section $\\langle \\sigma_\\text{ann}v_\\text{r}\\rangle$, the temperature $x_\\ast$ and the actual WIMPs abundance $Y(x_\\ast)$ are exactly known. This value provides the true initial condition for the usual differential equation that have to be integrated in the interval $x\\ge x_\\ast$. The matching of the two abundances at $x_\\ast$ is continuous and differentiable. The dependence of the present relic abundance on the abundance at an intermediate temperature is an exact result. The exact theory suggests a new analytical approximation that furnishes the relic abundance accurate at the level of $1\\%-2\\%$ in the case of $S$-wave and $P$-wave scattering cross sections. We conclude the paper studying the evolution of the WIMPs chemical potential and the entropy production using methods of non equilibrium thermodynamics.

  5. FREEZING-STRESS-RESPONSIVE GENES AND THEIR EXPRESSION IN BARLEY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Injury of barley plants by spring freezing is a major cause of crop loss, but most cold tolerance research has focused on cold acclimation, which confers freezing tolerance upon exposure to low nonfreezing temperatures. In order to address freezing tolerance per se, we have chosen a cold sensitive ...

  6. VISUALIZATION OF FREEZING PROGRESSION IN TURFGRASSES USING INFRARED VIDEO THERMOGRAPHY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Freezing injury can be a significant problem in turfgrasses. Understanding how freezing develops and ramifies throughout the plant could assist in the development of improved management or screening processes for cultivar improvemen. The development of freezing injury is not well understand due pa...

  7. On the freeze quantifier in Constraint LTL: decidability and complexity

    E-print Network

    Doyen, Laurent

    On the freeze quantifier in Constraint LTL: decidability and complexity St´ephane Demri a,1 , Ranko of operational models with constraints. The freeze quantifier can be part of the language, as in some real with -abstraction etc.). We show that Constraint LTL over the simple domain N, = augmented with the freeze

  8. Continuous decoupling and freeze-out Jorn Knoll

    E-print Network

    Knoll, Jörn

    Continuous decoupling and freeze-out J¨orn Knoll GSI, Helmholtzzentrum f¨ur Schwerionenforschung, 64291 Darmstadt, Germany The decoupling and freeze-out of energetic nuclear collisions is anal- ysed and generalise frequently employed instantaneous freeze-out procedures. Simple relations between the damping

  9. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false To can, freeze, or dehydrate. 929.11 Section 929.11... LONG ISLAND IN THE STATE OF NEW YORK Order Regulating Handling Definitions § 929.11 To can, freeze, or dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or...

  10. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Quick freeze treatment requirements. 305.7 Section 305... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze treatment for fruits and vegetables imported into the United States or...

  11. TRACKING MELT-FREEZE CRUST EVOLUTION Ryan Buhler

    E-print Network

    Jamieson, Bruce

    TRACKING MELT-FREEZE CRUST EVOLUTION Ryan Buhler 1 , Sascha Bellaire 1 , Bruce Jamieson 1,2 1 Dept, Canada Melt-freeze crusts are one of the most critical layers for slab avalanche formation. These layers can be inconsistent amongst multiple observers. In order to improve the way melt-freeze crusts

  12. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false To can, freeze, or dehydrate. 929.11 Section 929.11... LONG ISLAND IN THE STATE OF NEW YORK Order Regulating Handling Definitions § 929.11 To can, freeze, or dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or...

  13. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false To can, freeze, or dehydrate. 929.11 Section 929.11... LONG ISLAND IN THE STATE OF NEW YORK Order Regulating Handling Definitions § 929.11 To can, freeze, or dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or...

  14. 47 CFR 64.636 - Prohibition of default provider freezes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Prohibition of default provider freezes. 64.636... Customer Premises Equipment for Persons With Disabilities § 64.636 Prohibition of default provider freezes. (a) A default provider freeze prevents a change in an iTRS user's default provider selection...

  15. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Quick freeze treatment requirements. 305.7 Section 305... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze treatment for fruits and vegetables imported into the United States or...

  16. LTL with the Freeze Quantifier and Register Automata Stephane Demri

    E-print Network

    Doyen, Laurent

    LTL with the Freeze Quantifier and Register Automata St´ephane Demri LSV, CNRS & ENS Cachan, temporal logics are extended with the freeze quantifier, first-order logics with predicates over the data of standard decision problems for LTL with the freeze quan- tifier (LTL ), 2-variable first-order logic (FO2

  17. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false To can, freeze, or dehydrate. 929.11 Section 929.11... LONG ISLAND IN THE STATE OF NEW YORK Order Regulating Handling Definitions § 929.11 To can, freeze, or dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or...

  18. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false To can, freeze, or dehydrate. 929.11 Section 929.11... LONG ISLAND IN THE STATE OF NEW YORK Order Regulating Handling Definitions § 929.11 To can, freeze, or dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or...

  19. Freeze After Writing Quasi-Deterministic Parallel Programming with LVars

    E-print Network

    Connelly, Kay

    Freeze After Writing Quasi-Deterministic Parallel Programming with LVars Lindsey Kuper Indiana the ability to "freeze" and then read the contents of an LVar directly. Second, we add the ability to attach and freezing enable an expressive and useful style of parallel program- ming. We prove that in a language where

  20. 47 CFR 64.636 - Prohibition of default provider freezes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Prohibition of default provider freezes. 64.636... Customer Premises Equipment for Persons With Disabilities § 64.636 Prohibition of default provider freezes. (a) A default provider freeze prevents a change in an iTRS user's default provider selection...

  1. Probabilistic Network Formation through Coverage and Freeze-Tag

    E-print Network

    Isler, Ibrahim Volkan

    Probabilistic Network Formation through Coverage and Freeze-Tag Eric Meisner1 , Wei Yang1 formation problem and other fundamental problems such as rendezvous, coverage and freeze-tag. 1.1 Related is closely related to the Freeze-Tag problem [4]. In fr

  2. Predicting equilibrium structures in freezing processes Dieter Gottwald

    E-print Network

    Likos, Christos N.

    Predicting equilibrium structures in freezing processes Dieter Gottwald Center for Computational candidate structures into which a simple fluid can freeze. In contrast to the conventional approach where American Institute of Physics. DOI: 10.1063/1.1901585 I. INTRODUCTION The freezing behavior of simple

  3. Experimental Verification of Morphological Instability in Freezing Aqueous Colloidal Suspensions

    E-print Network

    Wettlaufer, John S.

    Experimental Verification of Morphological Instability in Freezing Aqueous Colloidal Suspensions S; published 9 June 2008) We describe an experimental test of a new theory of the unidirectional freezing of aqueous colloidal suspensions. At low freezing speeds a planar ice lens completely rejects the particles

  4. The Bottom-Up Freezing: An Approach to Neural Engineering

    E-print Network

    Ghorbani, Ali

    The Bottom-Up Freezing: An Approach to Neural Engineering Ali Farzan and Ali A. Ghorbani Faculty of the proposed method is to reduce the size of the network by freezing any node that does not actively presents a new pruning method. The proposed method, which we call Bottom-Up Freezing (BUF), alters

  5. Modification of physical properties of freeze-dried rice

    NASA Technical Reports Server (NTRS)

    Huber, C. S.

    1971-01-01

    Freeze cycling process consists of alternately freezing and thawing precooked rice for two cycles, rice is then frozen and freeze-dehydrated in vacuum sufficient to remove water from rice by sublimitation. Process modifies rice grain structure and porosity, enabling complete rehydration in one minute in hot water.

  6. STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING

    E-print Network

    STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING BY ALBERT W. COLLIER AND KENNETH T, Director STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING By ALBERT W. COLLIER and KENNETH T_________________________________________________ 76 u #12;STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING By ALBERT W. COLLIER, Fishery

  7. Solvation versus freezing in a heteropolymer globule Phillip L. Geissler*

    E-print Network

    Geissler, Phillip

    the mol- ecule, and Tfr is the freezing temperature below which the ground state dominates. For strongSolvation versus freezing in a heteropolymer globule Phillip L. Geissler* Department of Chemistry a freezing transition, in which the freedom of chain shape fluctuations is sacrificed for the choice

  8. The depressive situation

    PubMed Central

    A. Jacobs, Kerrin

    2013-01-01

    From a naturalistic perspective on mental illness, depression is often described in terms of biological dysfunctions, while a normative perspective emphasizes the lived experience of depression as a harmful condition. The paper relates a conceptual analysis of “depressive situation” to an analysis of the lived experience of depression. As such, it predominantly aims to specify depression as a harmful condition in lights of normative perspective on mental disorder, but partially refers to empirical research, i.e., naturalistic perspective on depression, to exemplarily stress on the methodological merits and limits of relating phenomenological considerations closer to empirical research. The depressive situation is further specified with an examination of the evaluative dynamics by which individuals meaningfully relate to themselves, others and the world. These evaluative dynamics emerge out of the interplay of pre-reflective and reflective processes, which are significantly altered in depression. Such alterations of the evaluative structure are inextricably intertwined with significant distortions of practical sense in depression. From a phenomenological perspective, these distortions of practical sense show in characteristic experiences of evaluative incoherence and impairments of agency. Finally, this paper focuses on an examination of “evaluative incapacity,” which has the integrative potential to capture a range of typical changes of meaningful relatedness that determine the depressive situation. PMID:23882238

  9. Depression associated with dementia.

    PubMed

    Gutzmann, H; Qazi, A

    2015-06-01

    Depression and cognitive disorders, including dementia and mild cognitive impairment, are common disorders in old age. Depression is frequent in dementia, causing distress, reducing the quality of life, exacerbating cognitive and functional impairment and increasing caregiver stress. Even mild levels of depression can significantly add to the functional impairment of dementia patients and the severity of psychopathological and neurological impairments increases with increasing severity of depression. Depressive symptoms may be both a risk factor for, as well as a prodrome of dementia. Major depressive syndrome of Alzheimer's disease may be among the most common mood disorders of older adults. Treating depression is therefore a key clinical priority to improve the quality of life both of people with dementia as well as their carergivers. Nonpharmacological approaches and watchful waiting should be attempted first in patients who present with mild to moderate depression and dementia. In cases of severe depression or depression not able to be managed through nonpharmacological means, antidepressant therapy should be considered. PMID:25962363

  10. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    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.

  11. Numerical study of two-dimensional freezing in an annulus

    SciTech Connect

    Sablani, S.S.; Venkateshan, S.P.; Sastri, V.M.K. )

    1990-07-01

    An evaluation is made of the results of a numerical study on two-dimensional freezing in an annulus made up of an initially superheated phase-change medium. Numerical results are used to deduce a relation between the nondimensional discharge time and the other parameters. The velocity of the freeze front decreases with time because of the increase of interface area as the freezing proceeds radially outward, followed by a marginal decrease in the freezing rate due to the presence of the adiabatic surface; sensible cooling then occurs only where the freeze front has already reached the adiabatic surface. 6 refs.

  12. The energy equation for freezing of biological tissue

    SciTech Connect

    Rubinsky, B. )

    1989-11-01

    In the past, the process of freezing in biological tissue was modeled using the regular energy equation for a homogeneous compound. New experimental evidence shows that in tissue the water freezes separately in the vascular system and in the cells. The freezing process is affected by the water transport between the cells and the blood vessels. A new equation was developed to model the experimental results. In this work the general equation for freezing of biological tissue will be presented together with a linearized version of the new equation. A perturbation solution is obtained for the linearized equation to illustrate the effect of the water transport on the freezing process in tissue.

  13. Diabetes and Depression

    PubMed Central

    de Groot, Mary; Golden, Sherita Hill

    2015-01-01

    Diabetes and depression occur together approximately twice as frequently as would be predicted by chance alone. Comorbid diabetes and depression are a major clinical challenge as the outcomes of both conditions are worsened by the other. Although the psychological burden of diabetes may contribute to depression, this explanation does not fully explain the relationship between these 2 conditions. Both conditions may be driven by shared underlying biological and behavioral mechanisms, such as hypothalamic-pituitary-adrenal axis activation, inflammation, sleep disturbance, inactive lifestyle, poor dietary habits, and environmental and cultural risk factors. Depression is frequently missed in people with diabetes despite effective screening tools being available. Both psychological interventions and antidepressants are effective in treating depressive symptoms in people with diabetes but have mixed effects on glycemic control. Clear care pathways involving a multidisciplinary team are needed to obtain optimal medical and psychiatric outcomes for people with comorbid diabetes and depression. PMID:24743941

  14. Ethiopathogenesis of Depressive Disorders

    PubMed Central

    Pasquini, M; Berardelli, I; Biondi, M

    2014-01-01

    Etiology of depressive disorders is still unknown. Several factors are involved in its pathophysiology such as neurotransmitters and neuroendocrine alterations, genetics, life events and their appraisal. Some of these components are strictly linked. Subjects with a family member affected by mood disorders are more prone to suffer from depressive disorders. It is also true that receiving feedbacks of indifference or neglect during childhood from one parent who suffer from depression may represent a factor of vulnerability. Indeed, reaction to a specific negative event may determine an increased allostasis which lead to a depressive episode. Thus, a psychological cause does not exclude a neurobiological cascade. Whereas in other cases recurrent depressive episodes appear in absence of any negative life event. This review provides a set of data regarding the current etiopathogenesis models of depression, with a particular attention to the neurobiological correlates and vulnerability factors. PMID:25614753

  15. [Depression in cancer patients].

    PubMed

    Sperner-Unterweger, Barbara

    2015-08-01

    Cancer patients often suffer from major depression or depressive syndromes. Although it is well known that depressive symptoms can appear at any time during the course of an oncological disease, certain periods for instance time after diagnosis carry a higher risk. Reported prevalence rates differ widely (up to 60%), reflecting also diagnostic difficulties. Oncologists recognize depression in their patients only in 15 to 50% and the percentage of patients who receive adequate therapy is even lower. Consequently, this leads to a reduced quality of life. Furthermore, impaired compliance/adherence and consequently a poorer prognosis of the oncological disease are discussed in this context. It should be also emphasized, that concomitant depression increases the risk of suicide in cancer patients. Although the number of clinical trials using either psychotherapy or antidepressant medication for the therapy of depression in cancer patients is limited, good therapeutic options are available. PMID:26141741

  16. Pulsed depressed collector

    DOEpatents

    Kemp, Mark A

    2015-11-03

    A high power RF device has an electron beam cavity, a modulator, and a circuit for feed-forward energy recovery from a multi-stage depressed collector to the modulator. The electron beam cavity include a cathode, an anode, and the multi-stage depressed collector, and the modulator is configured to provide pulses to the cathode. Voltages of the electrode stages of the multi-stage depressed collector are allowed to float as determined by fixed impedances seen by the electrode stages. The energy recovery circuit includes a storage capacitor that dynamically biases potentials of the electrode stages of the multi-stage depressed collector and provides recovered energy from the electrode stages of the multi-stage depressed collector to the modulator. The circuit may also include a step-down transformer, where the electrode stages of the multi-stage depressed collector are electrically connected to separate taps on the step-down transformer.

  17. Relationship dynamics around depression in gay and lesbian couples.

    PubMed

    Thomeer, Mieke Beth; Reczek, Corinne; Umberson, Debra

    2015-12-01

    Research on intimate relationship dynamics around depression has primarily focused on heterosexual couples. This body of work shows that wives are more likely than husbands to offer support to a depressed spouse. Moreover, when wives are depressed, they are more likely than husbands to try and shield their spouse from the stress of their own depression. Yet, previous research has not examined depression and relationship dynamics in gay and lesbian couples. We analyze in-depth interviews with 26 gay and lesbian couples (N = 52 individuals) in which one or both partners reported depression. We find evidence that dominant gender scripts are both upheld and challenged within gay and lesbian couples, providing important insight into how gender operates in relation to depression within same-sex contexts. Our results indicate that most gay and lesbian partners offer support to a depressed partner, yet lesbian couples tend to follow a unique pattern in that they provide support both as the non-depressed and depressed partner. Support around depression is sometimes viewed as improving the relationship, but if the support is intensive or rejected, it is often viewed as contributing to relationship strain. Support is also sometimes withdrawn by the non-depressed partner because of caregiver exhaustion or the perception that the support is unhelpful. This study points to the importance of considering depression within gay and lesbian relational contexts, revealing new ways support sustains and strains intimate partnerships. We emphasize the usefulness of deploying couple-level approaches to better understand depression in sexual minority populations. PMID:26523788

  18. Recognition of Depression in the Primary School Child. Selected Papers, Number 56.

    ERIC Educational Resources Information Center

    Schick, Tom

    Real depression in children can manifest itself in many ways. Every human being is somewhat different and consequently distress signals and breaking points do not always imitate each other. What remains constant is the internal emotional desert and emptiness. Depression is not just feeling sad or lethargic. Depression is a state in which…

  19. To freeze or not to: Quantum correlations under local decoherence

    E-print Network

    Titas Chanda; Amit Kumar Pal; Anindya Biswas; Aditi Sen De; Ujjwal Sen

    2015-09-10

    We provide necessary and sufficient conditions for freezing of quantum correlations as measured by quantum discord and quantum work deficit in the case of bipartite as well as multipartite states subjected to local noisy channels. We recognize that inhomogeneity of the magnetizations of the shared quantum states plays an important role in the freezing phenomena. We show that the frozen value of the quantum correlation and the time interval for freezing follow a complementarity relation. For states which do not exhibit "exact" freezing, but can be frozen "effectively", by having a very slow decay rate with suitable tuning of the state parameters, we introduce an index -- the freezing index -- to quantify the goodness of freezing. We find that the freezing index can be used to detect quantum phase transitions and discuss the corresponding scaling behavior.

  20. Dynamical Freeze-out in 3-Fluid Hydrodynamics

    E-print Network

    V. N. Russkikh; Yu. B. Ivanov

    2007-10-19

    Freeze-out procedure accepted in the model of 3-fluid dynamics (3FD) is analyzed. This procedure is formulated in terms of drain terms in hydrodynamic equations. Dynamics of the freeze-out is illustrated by 1-dimensional simulations. It is demonstrated that the resulting freeze-out reveals a nontrivial dynamics depending on initial conditions in the expanding ``fireball''. The freeze-out front is not defined just ``geometrically'' on the condition of the freeze-out criterion met but rather is a subject the fluid evolution. It competes with the fluid flow and not always reaches the place where the freeze-out criterion is met. Dynamics of the freeze-out in 3D simulations is analyzed. It is demonstrated that the late stage of central nuclear collisions at top SPS energies is of the form of three (two baryon-rich and one baryon-free) fireballs separated from each other.

  1. Exotic Freezing of Response in Quantum Many-Body System

    E-print Network

    Arnab Das

    2010-11-01

    We show that when a quantum many-body system is subjected to coherent periodic driving, the response may exhibit exotic freezing behavior in high driving frequency ($\\omega$) regime. In a periodically driven classical thermodynamic system, freezing at high $\\omega$ occurs when $1/\\omega$ is much smaller than the characteristic relaxation time of the system, and hence the freezing always increases there as $\\omega$ is increased. Here, in the contrary, we see surprising non-monotonic freezing behavior of the response with $\\omega$, showing curious peak-valley structure. Quite interestingly, the entire system tends to freeze almost absolutely (the freezing peaks) when driven with a certain combination of driving parameters values (amplitude and $\\omega$) due to coherent suppression of dynamics of the quantum many-body modes, which has no classical analog. We demonstrate this new freezing phenomenon analytically (supported by large-scale numerics) for a general class of integrable quantum spin systems.

  2. Study of Transient Nuclei near Freezing

    NASA Astrophysics Data System (ADS)

    Isobe, Masaharu; Alder, Berni

    2011-03-01

    The molasses tail in dense hard core fluids is investigated by extensive event-driven molecular dynamics simulation through the orientational autocorrelation functions. Near the fluid- solid phase transition, there exist three regimes in the relaxation of the pair orientational autocorrelation function, namely the kinetic, molasses (stretched exponential), and diffusional power decay. The density dependence of both the molasses and diffusional power regimes are evaluated and the latter compares with theoretical predictions in three dimensions. The largest cluster at the freezing density of only a few sphere diameter in size persist for only about 30 picoseconds (~ 2.8 ×10-11 [s]). The most striking observation through the bond orientatinal order parameter is the dramatic increase of the cluster size as the freezing density is approached.

  3. Freeze-out parameters: lattice meets experiment

    E-print Network

    S. Borsanyi; Z. Fodor; S. D. Katz; S. Krieg; C. Ratti; K. K. Szabo

    2013-05-22

    We present our results for ratios of higher order fluctuations of electric charge as functions of the temperature. These results are obtained in a system of 2+1 quark flavors at physical quark masses and continuum extrapolated. We compare them to preliminary data on higher order moments of the net electric charge distribution from the STAR collaboration. This allows us to determine the freeze-out temperature and chemical potential from first principles. We also show continuum-extrapolated results for ratios of higher order fluctuations of baryon number. These will allow to test the consistency of the approach, by comparing them to the corresponding experimental data (once they become available) and thus extracting the freeze-out parameters in an independent way.

  4. Astronomical bounds on future big freeze singularity

    E-print Network

    Artyom V. Yurov; Artyom V. Astashenok; Pedro F. Gonzalez-Diaz

    2007-05-28

    Recently it was found that dark energy in the form of phantom generalized Chaplygin gas may lead to a new form of the cosmic doomsday, the big freeze singularity. Like the big rip singularity, the big freeze singularity would also take place at a finite future cosmic time, but unlike the big rip singularity it happens for a finite scale factor.Our goal is to test if a universe filled with phantom generalized Chaplygin gas can conform to the data of astronomical observations. We shall see that if the universe is only filled with generalized phantom Chaplygin gas with equation of state $p=-c^2s^2/\\rho^{\\alpha}$ with $\\alphafreeze doomsday.

  5. Ground freezing for containment of hazardous waste

    SciTech Connect

    Sayles, F.N.; Iskandar, I.K.

    1998-07-01

    The freezing of ground for the containment of subsurface hazardous waste is a promising method that is environmentally friendly and offers a safe alternative to other methods of waste retention in many cases. The frozen soil method offers two concepts for retaining waste. One concept is to freeze the entire waste area into a solid block of frozen soil thus locking the waste in situ. For small areas where the contaminated soil does not include vessels that would rupture from frost action, this concept may be simpler to install. A second concept, of course, is to create a frozen soil barrier to confine the waste within prescribed unfrozen soil boundaries; initial research in this area was funded by EPA, Cincinnati, OH, and the Army Corps of Engineers. The paper discusses advantages and limitations, a case study from Oak Ridge, TN, and a mesh generation program that simulates the cryogenic technology.

  6. Developing a new multi-dimensional depression assessment scale 

    E-print Network

    Cheung, Ho Nam

    2010-07-01

    . In Study 1, an 85-item questionnaire containing all the possible depressive symptoms was distributed to 87 participants from mental health professions. Based on their clinical experience and knowledge, they rated how typical each symptom was on a 5-point...

  7. Anxious forms of depression.

    PubMed

    Goldberg, David P

    2014-04-01

    Previous research has described distinctive features for anxious and nonanxious forms of major depression. The concept of "mixed anxiety depression disorder" (MADD) refers to a milder degree of the anxious form of depression, since the depressive symptoms fall short of the number required for a diagnosis of major depression. It is argued that this can be thought of as a subclinical form of anxious depression, rather than a separate disorder in its own right. In view of its substantial prevalence in general medical settings, its associated disability and its public health importance, it deserves to be recognized, and seen as being continuous with the more severe forms of anxious depression. It will therefore be included in the Field Trials of the version of the ICD-11 (where ICD is the International Classification of Disease) intended for primary care. It is argued that current anxiety, depression (without anxiety), and anxious depression would cover most of the psychologically distressed patients seen in general medical settings, using a pseudodimensional system. PMID:24281827

  8. Fast Melting and Freezing for Microgravity Experiments

    NASA Technical Reports Server (NTRS)

    Poorman, Richard M.

    1987-01-01

    Commercial tube welders adapted to metallurgical research. Proposed furnace melts and resolidifies small metal samples during brief periods. In furnace, sample surrounded by large heat sinks and rapidly heated near midlength by intense source of heat. Furnace intended for use in experiments in microgravity: entire melting-and-freezing process requires less than 20 s of near weightlessness experienced in parabolic climb and dive of KC-135 airplane.

  9. Vogel-Fulcher freezing in relaxor ferroelectrics

    SciTech Connect

    Pirc, R.; Blinc, R.

    2007-07-01

    A physical mechanism for the freezing of polar nanoregions (PNRs) in relaxor ferroelectrics is presented. Assuming that the activation energy for the reorientation of a cluster of PNRs scales with the mean volume of the cluster, the characteristic relaxation time {tau} is found to diverge as the cluster volume reaches the percolation limit. Applying the mean field theory of continuum percolation, the familiar Vogel-Fulcher equation for the temperature dependence of {tau} is derived.

  10. Steam consumption reduction by eutectic freeze crystallization

    SciTech Connect

    Bichsel, S.E.; Cleary, M.; Barron, T.S.; Heist, J.A.

    1985-01-01

    Steam production in American beet sugar factories can be reduced by 600 pounds per ton of beets by using hydrate freeze crystallization in place of pan evaporators for sugar crystallization. This is a relatively constant number, regardless of current factory energy use. Further reduction is limited by the juice heating needs in the purification operations. Steam for juice heating is 20 to 30% on beets, or 400 to 600 pounds of steam per ton. In efficient factories this is about the steam flow to the evaporators when the pan crystallizers are replaced by freeze crystallization. An approach is described here for a rapid evaluation of effects on the steam balance of basic process changes. It provides a visual guide to restructuring the steam balance that simplifies optimization when such changes are made. The graphic approach is useful in illustrating methods of reducing energy use in a sugar factory, in addition to the current analysis of integration of the hydrate freeze process. For example, membrane and vapor recompression evaporators for juice concentration must be accompanied by major factory modifications to produce any net savings of steam. The reason is the needs for specific steam quantity and quality for the pan evaporators and juice heaters, supplied through the current evaporator trains. Reduction of the steam rate below 25 to 35% on beets will require changes to the conventional juice purification process.

  11. Disaggregating meteorites by automated freeze thaw.

    PubMed

    Charles, Christopher R J

    2011-06-01

    An automated freeze-thaw (AFT) instrument for disaggregating meteorites is described. Meteorite samples are immersed in 18.2 M? water and hermetically sealed in a clean 30 ml Teflon vial. This vial and its contents are dipped between baths of liquid nitrogen and hot water over a number of cycles by a dual-stepper motor system controlled by LabView. Uniform and periodic intervals of freezing and thawing induce multiple expansions and contractions, such that cracks propagate along natural flaws in the meteorite for a sufficient number of AFT cycles. For the CR2 chondrite NWA801, the boundaries between different phases (i.e., silicates, metal, matrix) became progressively weaker and allowed for an efficient recovery of 500 individual chondrules and chondrule fragments spanning 0.2-4.7 mm diameters after 243 AFT cycles over 103.3 h. Further FT experiments on a basalt analog showed that the time required for freezing and thawing the same number of cycles can be reduced by a factor of ?4. PMID:21721725

  12. Radiobrightness of diurnally heated, freezing soil

    NASA Technical Reports Server (NTRS)

    England, Anthony W.

    1990-01-01

    Freezing and thawing soils exhibit unique radiometric characteristics. To examine these characteristics, diurnal insolation is modeled as one-dimensional heating of a moist soil half-space during a typical fall at a northern Great Plains site. The one-dimensional heat flow equation is nonlinear because both the enthalpy (the change in internal energy with temperature at constant pressure) and the thermal conductivity of freezing soils are nonlinear functions of temperature. The problem is particularly difficult because phase boundaries propagate in time, and because soils, particularly clay-rich soils, freeze over a range of temperatures rather than at 0 C. Diurnal radiobrightness curves at 10.7, 18.0, and 37.0-GHz were computed for each month. The 37.0-GHz radiobrightness best tracks soil surface temperature; the 10.7-37.0-GHz spectral gradient of thawed soils is strongly positive; the spectral gradient of frozen soils is slightly negative; and the midnight-to-noon spectral gradient is shifted by approximately +0.1 K/GHz by diurnal changes in the surface temperature and the thermal gradient. These observations support the use of the scanning multichannel microwave radiometer 37.0-GHz radiobrightness and its 10.7-37.0-GHz spectral gradient as discriminants in a frozen soil classifier for high-latitude prairie.

  13. Infrared Freezing of Euclidean QCD observables

    E-print Network

    Paul M. Brooks; C. J. Maxwell

    2006-08-22

    We consider the leading one-chain term in a skeleton expansion for QCD observables and show that for energies Q^2>\\Lambda^2, where Q^2=\\Lambda^2 is the Landau pole in the coupling, the skeleton expansion result is equivalent to the standard Borel integral representation, with ambiguities related to infrared (IR) renormalons. For Q^2freezing behaviour, vanishing at Q^2=0. Finiteness at Q^2=\\Lambda^2 implies specific relations between the residues of IR and UV renormalons in the Borel plane. These relations, only one of which has previously been noted (though it remained unexplained) are shown to follow from the continuity of the characteristic function in the skeleton expansion. By considering the compensation of non-perturbative and perturbative ambiguities we are led to a result for the Q^2 dependence of these observables at all Q^2, in which there is a single undetermined non-perturbative parameter, and which involves the skeleton expansion characteristic function. The observables freeze to zero in the infrared. We briefly consider the freezing behaviour of the Minkowskian R_{e+e-} ratio.

  14. Freezing promotes perception of coarse visual features.

    PubMed

    Lojowska, Maria; Gladwin, Thomas E; Hermans, Erno J; Roelofs, Karin

    2015-12-01

    Freezing is an evolutionarily preserved defensive behavior, characterized by immobility and heart rate deceleration, which is thought to promote visual perception. Rapid perceptual assessment of threat is crucial in life-threatening situations; for example, when policemen need to make split-second decisions about the use of deadly force. Here, we hypothesized that freezing is specifically associated with better perception of rapidly processed coarse, low-spatial frequency (LSF) features. We used a visual discrimination task in which participants determined the orientation of LSF and high-spatial frequency (HSF) gratings under threat of shock and safe conditions. As predicted, threat anticipation improved perception of LSF at the expense of HSF gratings. Crucially, stronger decrease in heart rate, a parasympathetic physiological index of freezing, was linked to better perception of LSF. These results provide empirical evidence for the comobilization of physiological and perceptual processes, which may play an important role in decision making under acute stress. (PsycINFO Database Record PMID:26595839

  15. Atmospheric freeze drying assisted by power ultrasound

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  16. Observations on the Freezing of Supercooled Pollen Washing Water by a New Electrodynamic Balance

    NASA Astrophysics Data System (ADS)

    Tong, Haijie; Pope, Francis D.; Kalberer, Markus

    2014-05-01

    Primary biological particles can act as efficient ice nuclei (IN) by initiating freezing events at temperatures warmer than the homogenous freezing temperature [1, 2]. For example, pollen grain particles can trigger freezing events at temperatures as warm as -5 °C in the contact freezing mode [3]. More recently pollen residues, which are released by washing pollen grains in water, were also observed to act as efficient IN in the immersion mode [4, 5]. In this study we developed a new cold electrodynamic balance (CEDB) system and investigated the freezing properties of single particles of supercooled pollen washing water (SPWW). The EDB technique allows for a contact free measurement of freezing events. The phase of the particle (liquid or frozen solid) can be distinguished via measuring the Mie scattering signal from the particle. Furthermore the size of liquid (spherical) particles can be determined. The freezing events are characterized through the loss of the regular Mie scattering signal from the levitated droplet as it changes state from liquid to a frozen solid. The statistical freezing probabilities of SPWW were obtained in the temperature range: -15 to -40 °C. Each temperature measurement point consists of the analysis of 30-100 droplets. Preliminary conclusions are that SPWW is IN active in the immersion mode. Further discussion will focus on the temperature range of the IN activity, the important variables (other than temperature) for IN activity, other likely modes of IN activity, and the implications of these results in terms of the atmospheric relevance of SPWW. This study was supported by the NERC. We acknowledge Professor Jonathan Reid and James Davis from the University of Bristol for providing information of the design of the warm EDB system. References: [1] Möhler, O., et al. (2007) Biogeosciences, 4, 1059-1071. [2] Prenni, A. J., et al. (2009) Nat. Geosci., 2, 401-404. [3] Diehl, K., et al. (2002) Atmos. Res., 61, 125-133. [4] Pummer, B. G., et al. (2012) Atmos. Chem. Phys., 12, 2541-2550. [5] Augustin, S., et al. (2013) Atmos. Chem. Phys., 13, 10989-11003.

  17. Response of New zealand mudsnails Potamopyrgus antipodarum to freezing and near freezing fluctuating water temperatures

    USGS Publications Warehouse

    Moffitt, Christine M.; James, Christopher A.

    2012-01-01

    We explored the resilience of the invasive New Zealand mudsnail Potamopyrgus antipodarum to fluctuating winter freezing and near-freezing temperature cycles in laboratory tests. Our goal was to provide data to confirm field observations of mortality and presumed mortality in stream habitats with fluctuating freezing to near-freezing temperatures. We tested individuals from 2 locations with distinctly different thermal regimes and population densities. One location had low snail densities and water temperatures with strong diel and seasonal water variation. The other location had high snail densities and nearly constant water temperatures. Groups of individuals from both locations were tested in each of 3 laboratory-created diel thermal cycles around nominal temperatures of 0, 2, or 4°C. Mortality occurred in cycles around 0°C in both populations, and little to no mortality occurred at temperatures >0°C. Individuals from both sources held in diel 0°C cycles for 72 h showed 100% mortality. Our findings support observations from published field studies that survival was limited in infested habitats subject to freezing temperatures.

  18. Nutritional Aspects of Depression.

    PubMed

    Lang, Undine E; Beglinger, Christoph; Schweinfurth, Nina; Walter, Marc; Borgwardt, Stefan

    2015-01-01

    Several nutrition, food and dietary compounds have been suggested to be involved in the onset and maintenance of depressive disorders and in the severity of depressive symptoms. Nutritional compounds might modulate depression associated biomarkers and parallel the development of depression, obesity and diabetes. In this context, recent studies revealed new mediators of both energy homeostasis and mood changes (i.e. IGF-1, NPY, BDNF, ghrelin, leptin, CCK, GLP-1, AGE, glucose metabolism and microbiota) acting in gut brain circuits. In this context several healthy foods such as olive oil, fish, fruits, vegetables, nuts, legumes, poultry, dairy and unprocessed meat have been inversely associated with depression risk and even have been postulated to improve depressive symptoms. In contrast, unhealthy western dietary patterns including the consumption of sweetened beverage, refined food, fried food, processed meat, refined grain, and high fat diary, biscuits, snacking and pastries have been shown to be associated with an increased risk of depression in longitudinal studies. However, it is always difficult to conclude a real prospective causal relationship from these mostly retrospective studies as depressed individuals might also change their eating habits secondarily to their depression. Additionally specific selected nutritional compounds, e.g. calcium, chromium, folate, PUFAs, vitamin D, B12, zinc, magnesium and D-serine have been postulated to be used as ad-on strategies in antidepressant treatment. In this context, dietary and lifestyle interventions may be a desirable, effective, pragmatical and non-stigmatizing prevention and treatment strategy for depression. At last, several medications (pioglitazone, metformin, exenatide, atorvastatin, gram-negative antibiotics), which have traditionally been used to treat metabolic disorders showed a certain potential to treat depression in first randomized controlled clinical trials. PMID:26402520

  19. Clinical and Physiological Correlates of Irritability in Depression: Results from the Netherlands Study of Depression and Anxiety

    PubMed Central

    Verhoeven, Floor E. A.; Booij, Linda; Van der Wee, Nic J. A.; Penninx, Brenda W. H. J.; Van der Does, A. J. Willem

    2011-01-01

    Objective. Irritable and nonirritable depressed patients differ on demographic and clinical characteristics. We investigated whether this extends to psychological and physiological measures. Method. We compared irritable and nonirritable unipolar depressed patients on symptomatology, personality, and (psycho)physiological measures (cortisol, cholesterol, and heart rate variability). Symptomatology was reassessed after one year, and we also compared depressed patients who were irritable or non-irritable at both time points (Irr++ versus Irr??). Results. Almost half (46%; N = 420) of the sample was classified as irritable. These patients scored higher on depression severity, anxiety, hypomanic symptoms, and psychological variables. No differences were observed on physiological markers after correction for depression severity. The same pattern was found when comparing Irr++ and Irr?? groups. Conclusion. Irritable and non-irritable depressed patients differ on clinical and psychological variables, but not on the currently investigated physiological markers. The clinical relevance of the distinction and the significance of the hypomanic symptoms remain to be demonstrated. PMID:22110910

  20. Viscosity Depressants for Coal Liquefaction

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.

    1983-01-01

    Proposed process modification incorporates viscosity depressants to prevent coal from solidifying during liquefaction. Depressants reduce amount of heat needed to liquefy coal. Possible depressants are metallic soaps, such as stearate, and amides, such as stearamide and dimer acid amides.

  1. Variation of the average 'freezing-in' temperature of oxygen ions with solar wind speed

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Vogt, C.

    1980-01-01

    Observations of the average oxygen ionization equilibrium as a function of speed of the solar wind are presented. At low solar wind speeds they indicate a coronal temperature at the freezing-in point of (1.6 + or - 0.2) x 10 to the 6th K. At speeds above 450 km/sec the apparent temperature starts to rise rapidly. This rise is tentatively interpreted in terms of a lack of thermodynamic equilibrium in the source region.

  2. ‘I am not a depressed person’: How identity conflict affects help-seeking rates for major depressive disorder

    PubMed Central

    2012-01-01

    Background There is a significant treatment gap for patients with depression. A third of sufferers never seek help, and the vast majority of those who do only do so after considerable delay. Little is understood regarding poor help-seeking rates amongst people with depression, with existing research mainly focussed on the impact of barriers to treatment. The current study explored psychological factors affecting help-seeking behaviour in clinically depressed individuals. Methods Semi-structured interviews were conducted with 20 current or previously clinically depressed participants who either had or had not sought professional help. Thematic analysis was used to analyse results. Results The onset of depressive symptoms created conflict with participants’ identity and personal goals. Delays in seeking help were primarily attributed to the desire to protect identity and goals from the threat of depressive symptoms. Participants used avoidance strategies to reduce the perceived threat of depressive symptoms on identity. These strategies interfered with help-seeking. Help-seeking was only undertaken once participants reached a point of acceptance and began to make concessions in their identity and goals, at which time they reduced their use of avoidance. Conclusions Difficulties resolving conflict between identity and depressive symptoms may account for significant delays in seeking help for depression. The results have implications for predicting health behaviour and improving treatment uptake for depression, and may inform existing help-seeking models. PMID:23031330

  3. Equilibrium freezing of leaf water and extracellular ice formation in Afroalpine 'giant rosette' plants.

    PubMed

    Beck, E; Schulze, E D; Senser, M; Scheibe, R

    1984-09-01

    The water potentials of frozen leaves of Afroalpine plants were measured psychrometrically in the field. Comparison of these potentials with the osmotic potentials of an expressed cellular sap and the water potentials of ice indicated almost ideal freezing behaviour and suggested equilibrium freezing. On the basis of the osmotic potentials of expressed cellular sap, the fractions of frozen cellular water which correspond to the measured water potentials of the frozen leaves could be determined (e.g. 74% at -3.0° C). The freezing points of leaves were found to be in the range between 0° C and -0.5° C, rendering evidence for freezing of almost pure water and thus confirming the conclusions drawn from the water-potential measurements. The leaves proved to be frost resistant down to temperatures between -5° C and -15° C, as depending on the species. They tolerated short supercooling periods which were necessary in order to start ice nucleation. Extracellular ice caps and ice crystals in the intercellular space were observed when cross sections of frozen leaves were investigated microscopically at subfreezing temperatures. PMID:24253100

  4. Depression Begets Depression: Comparing the Predictive Utility of Depression and Anxiety Symptoms to Later Depression

    ERIC Educational Resources Information Center

    Keenan, Kate; Feng, Xin; Hipwell, Alison; Klostermann, Susan

    2009-01-01

    Background: The high comorbidity between depressive and anxiety disorders, especially among females, has called into question the independence of these two symptom groups. It is possible that childhood anxiety typically precedes depression in girls. Comparing of the predictive utility of symptoms of anxiety with the predictive utility of symptoms…

  5. Postpartum Depression: An Overview.

    ERIC Educational Resources Information Center

    Albright, Angela

    1993-01-01

    Occurring in about 12 percent of postpartum women, postpartum depression has been focus of considerable research. Variables that have been correlated with postpartum depression range from biological causes, to lack of social support, to relationship with husband, to attributional styles, to psychodynamic explanations. There is need for more…

  6. Real Stories of Depression

    MedlinePLUS Videos and Cool Tools

    ... and Depression Background on Educational Materials Resources for Health Care Providers Public Service Announcements (PSAs) Join A Study Depression Studies for Adults Contact Us Staff Directories Privacy ... The National Institute of Mental Health (NIMH) is part of the National Institutes of ...

  7. [Depression as chronobiological illness].

    PubMed

    Kálmán, Janos; Kálmán, Sára

    2009-06-01

    Chronobiological problems are always present as aetiological or pathoplastic conditions almost in all psychiatric disorders and considered as the greatest contributors to the mood and sleep disorders associated problems. The present review summarise the recent advances in the chronobiology research from the point of the clinician with particular emphasis on the psychobiology and pharmacotherapy of the depression. Human behaviour builds up from different length of circadian, ultradian and seasonal rhytms, strictly controlled by a hierarchical organisation of sub-cellullar, cellular, neuro-humoral and neuro-immunological clock systems. These internal clock systems are orchestrated at molecular level by certain clock genes and on the other hand--at neuro-humoral level--by the effect of the sleep hormone, melatonine, produced by the neurons of the suprachiasmatic nucleus (SCN). Beside the biological factors, social interactions are also considered as important regulators of the biological clock systems. The pacemaker centers of the SCN receive efferents from the serotoninergic raphe nuclei in order to regulate stress responses and neuroimmunological functions. The direction and the level of the chronobiological desynchronisation could be totally divergent in the case of the different affective disorders. Different chronobiological interventions are required therefore in the case of the advanced and delayed sleep disorders. Sleeping disorders are considered as the most recognised signs of the chronobiological desynchronisation in depression, but these symptoms are only the tip of the iceberg, since other chronobiological symptoms could be present due to the hidden physiological abnormalities. The serum melatonine profile is considered to be characteristic to age, gender and certain neuropsychiatric disorders. The natural and synthetic agonist of the melatonine receptors could be used as chronobiotics. The recently marketed agomelatine with a highly selective receptor binding profile (MT1 and MT2 agonism and 5HT2C antagonism) targets the desynchronised circadian rhytm in affective disorders and it has mainly antidepressive effect. Among the non-pharmacological chronobiological interventions, the different forms of the sleep deprivation, light and social rhytm therapies could offer alternative treatment options for the clinician. PMID:19827314

  8. Depression and Bipolar Support Alliance

    MedlinePLUS

    ... message JOINT COMMISSION LAUNCHES EDUCATIONAL CAMPAIGN ON ADULT DEPRESSION Educational Brochure Provides Guidance on Recognizing and Treating Depression [PDF] DBSA 2013–2017 STRATEGIC PLAN Learn how ...

  9. Treatments in depression

    PubMed Central

    Duval, Fabrice; Lebowitz, Barry D.; Macher, Jean-Paul

    2006-01-01

    Major depression is believed to be a multifactorial disorder involving predisposing temperament and personality traits, exposure to traumatic and stressful life events, and biological susceptibility. Depression, both unipolar and bipolar, is a “phasic” disease. Stressful life events are known to trigger depressive episodes, while their influence seems to decrease over the course of the illness. This suggests that depression is associated with progressive stress response abnormalities, possibly linked to impairments of structural plasticity and cellular resilience. It therefore appears crucial to adequately treat depression in the early stages of the illness, in order to prevent morphological and functional abnormalities. While evidence suggests that a severely depressed patient needs antidepressant drug therapy and that a non-severely depressed patient may benefit from other approaches (ie, “nonbiological”), little research has been done on the effectiveness of different treatments for depression. The assertion that the clinical efficacy of antidepressants is comparable between the classes and within the classes of those medications may be true from a statistical viewpoint, but is of limited value in practice. The antidepressant drugs may produce differences in therapeutic response and tolerability. Among the possible predictors of outcome in depression treatment, those derived from clinical assessment, neuroendocrine investigations, polysomnographic sleep parameters, genetic variables, and brain imaging techniques have been extensively studied. This article also reviews therapeutic strategies used when initial treatment fails, and describes briefly new concepts in antidepressant therapies such as the regulation of disturbances in circadian rhythms. The treatment of depressive illness does not stop with treatment of acute episodes, and has to be envisaged as a continuous therapeutic intervention, of which we are still not able to determine the optimal duration of treatment and the moment that it should be ceased. PMID:16889105

  10. Treatments in depression.

    PubMed

    Duval, Fabrice; Lebowitz, Barry D; Macher, Jean-Paul

    2006-01-01

    Major depression is believed to be a multifactorial disorder involving predisposing temperament and personality traits, exposure to traumatic and stressful life events, and biological susceptibility. Depression, both unipolar and bipolar, is a "phasic" disease. Stressful life events are known to trigger depressive episodes, while their influence seems to decrease over the course of the illness. This suggests that depression is associated with progressive stress response abnormalities, possibly linked to impairments of structural plasticity and cellular resilience. It therefore appears crucial to adequately treat depression in the early stages of the illness, in order to prevent morphological and functional abnormalities. While evidence suggests that a severely depressed patient needs antidepressant drug therapy and that a non-severely depressed patient may benefit from other approaches (ie, "nonbiological"), little research has been done on the effectiveness of different treatments for depression. The assertion that the clinical efficacy of antidepressants is comparable between the classes and within the classes of those medications may be true from a statistical viewpoint, but is of limited value in practice. The antidepressant drugs may produce differences in therapeutic response and tolerability. Among the possible predictors of outcome in depression treatment, those derived from clinical assessment, neuroendocrine investigations, polysomnographic sleep parameters, genetic variables, and brain imaging techniques have been extensively studied. This article also reviews therapeutic strategies used when initial treatment fails, and describes briefly new concepts in antidepressant therapies such as the regulation of disturbances in circadian rhythms. The treatment of depressive illness does not stop with treatment of acute episodes, and has to be envisaged as a continuous therapeutic intervention, of which we are still not able to determine the optimal duration of treatment and the moment that it should be ceased. PMID:16889105

  11. Effect of sugars on headgroup mobility in freeze-dried dipalmitoylphosphatidylcholine bilayers: solid-state 31P NMR and FTIR studies.

    PubMed Central

    Tsvetkova, N M; Phillips, B L; Crowe, L M; Crowe, J H; Risbud, S H

    1998-01-01

    The effect of the carbohydrates trehalose, glucose, and hydroxyethyl starch (HES) on the motional properties of the phosphate headgroup of freeze-dried dipalmitoylphosphatidylcholine (DPPC) liposomes was studied by means of 31P NMR, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The results show that trehalose, which is a strong glass former (Tg = 115 degreesC), elevates the onset of the lipid headgroup rotations and preserves some rotational mobility of the phosphate headgroups after cooling from the liquid-crystalline state. Glucose (Tg = 30 degreesC), a very effective depressant of the phase transition temperature of freeze-dried DPPC, markedly elevates the initiation of the temperature of headgroup rotations. On the other hand, the monosaccharide does not preserve the headgroup disordering when cooled from the liquid-crystalline state. These effects are consistent with formation of hydrogen bonds between the OH groups of the sugar and the polar headgroups of DPPC. They show, however, that hydrogen bonding is not sufficient for preservation of the dynamic properties of freeze-dried DPPC. HES, although a very good glass former (Tg > 110 degreesC), does not depress the phase transition temperature and affects only slightly the rotational properties of freeze-dried DPPC. This lack of effect of HES is associated with the absence of direct interactions with the lipid phosphates, as evidenced by the FTIR results. These data show that vitrification of the additive is not sufficient to affect the dynamic properties of dried DPPC. PMID:9826615

  12. Thermal properties of freezing bound water restrained by polysaccharides.

    PubMed

    Hatakeyama, Tatsuko; Tanaka, Masaru; Hatakeyama, Hyoe

    2010-01-01

    This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water. PMID:20557717

  13. Freeze-drying of live virus vaccines: A review.

    PubMed

    Hansen, L J J; Daoussi, R; Vervaet, C; Remon, J-P; De Beer, T R M

    2015-10-13

    Freeze-drying is the preferred method for stabilizing live, attenuated virus vaccines. After decades of research on several aspects of the process like the stabilization and destabilization mechanisms of the live, attenuated viruses during freeze-drying, the optimal formulation components and process settings are still matter of research. The molecular complexity of live, attenuated viruses, the multiple destabilization pathways and the lack of analytical techniques allowing the measurement of physicochemical changes in the antigen's structure during and after freeze-drying mean that they form a particular lyophilization challenge. The purpose of this review is to overview the available information on the development of the freeze-drying process of live, attenuated virus vaccines, herewith focusing on the freezing and drying stresses the viruses can undergo during processing as well as on the mechanisms and strategies (formulation and process) that are used to stabilize them during freeze-drying. PMID:26364685

  14. Theoretical and experimental studies on sequential freezing solar water heater

    SciTech Connect

    Jiang Xinian; Tao Zhen; Lu Junsheng; Ge Hongchuan )

    1994-08-01

    This article presents the principle of using sequential freezing for the purpose of freeze protection in a solar water heater. Sequential freezing is accomplished by maintaining a temperature gradient across the collector so that water is squeezed out of the collector rather than being trapped by ice at the ends of the tubes. The authors give the mathematical models of tubular sequential freezing, compare the predicted results of models with the measured data, and investigate the influences of various factors on the tubular sequential freezing state with the model. A series of experiments show that a solar water heater designed according to the principle of sequential freezing can operate effectively in winter without drain-down, electricity, and heat exchanger systems.

  15. Infrared freezing of Euclidean QCD observables

    SciTech Connect

    Brooks, Paul M.; Maxwell, C. J.

    2006-09-15

    We consider the leading one-chain term in a skeleton expansion for QCD observables and show that for energies Q{sup 2}>{lambda}{sup 2}, where Q{sup 2}={lambda}{sup 2} is the Landau pole of the coupling, the skeleton expansion result is equivalent to the standard Borel integral representation, with ambiguities related to infrared (IR) renormalons. For Q{sup 2}<{lambda}{sup 2} the skeleton expansion result is equivalent to a previously proposed modified Borel representation where the ambiguities are connected with ultraviolet (UV) renormalons. We investigate the Q{sup 2}-dependence of the perturbative corrections to the Adler-D function, the GLS sum rule and the polarized and unpolarized Bjorken sum rules. In all these cases the one-chain result changes sign in the vicinity of Q{sup 2}={lambda}{sup 2}, and then exhibits freezing behavior, vanishing at Q{sup 2}=0. Finiteness at Q{sup 2}={lambda}{sup 2} implies specific relations between the residues of IR and UV renormalon singularities in the Borel plane. These relations, only one of which has previously been noted (though it remained unexplained), are shown to follow from the continuity of the characteristic function in the skeleton expansion. By considering the compensation of nonperturbative and perturbative ambiguities we are led to a result for the Q{sup 2}-dependence of these observables at all Q{sup 2}, in which there is a single undetermined nonperturbative parameter, and which involves the skeleton expansion characteristic function. The observables freeze to zero in the infrared. We briefly consider the freezing behavior of the Minkowskian R{sub e{sup +}}{sub e{sup -}} ratio.

  16. Language use of depressed and depression-vulnerable college students

    E-print Network

    Hirschberg, Julia

    ) have speculated, in addition, that depressed individuals think a great deal about themselvesLanguage use of depressed and depression-vulnerable college students Stephanie S. Rude, Eva-Maria Gortner, and James W. Pennebaker University of Texas at Austin, USA Essays written by currently-depressed

  17. Pion Mass Shift and the Kinetic Freeze Out Process

    E-print Network

    Sven Zschocke; Laszlo P. Csernai

    2009-01-12

    The kinetic Freeze Out process of a pion gas through a finite layer with time-like normal is considered. The pion gas is described by a Boltzmann gas with elastic collisions among the pions. Within this model, the impact of the in-medium pion mass modification on the Freeze Out process is studied. A marginal change of the Freeze Out variables temperature and flow velocity and an insignificant modification of the frozen out particle distribution function has been found.

  18. Effect of local filtering on Freezing Phenomena of Quantum Correlation

    E-print Network

    Sumana Karmakar; Ajoy Sen; Amit Bhar; Debasis Sarkar

    2015-04-20

    General quantum correlations measures like quantum discord, one norm geometric quantum discord, exhibit freezing, sudden change, double sudden change behavior in their decay rates under different noisy channels. Therefore, one may attempt to investigate how the freezing behavior and other dynamical features are affected under application of local quantum operations. In this work, we demonstrate the effect of local filtering on the dynamical evolution of quantum correlations. We have found that using local filtering one may remove freezing depending upon the filtering parameter.

  19. Electrical Indicator of Imminent Freezing in Supercooled Water

    E-print Network

    James D. Brownridge

    2002-04-02

    Data is presented that demonstrate electrical activity and evidences of dipole alignment in supercooled water and heavy water before and after the onset of freezing. Voltage signals as high as 13 mV have been recorded. In some cases up to 3 seconds before latent heat is released and freezing began. The polarity of the voltage signals is suggestive of molecule dipole alignment prior to freezing.

  20. Displacement Echoes: Classical Decay and Quantum Freeze

    E-print Network

    Cyril Petitjean; Diego V. Bevilaqua; Eric J. Heller; Philippe Jacquod

    2007-04-23

    Motivated by neutron scattering experiments, we investigate the decay of the fidelity with which a wave packet is reconstructed by a perfect time-reversal operation performed after a phase space displacement. In the semiclassical limit, we show that the decay rate is generically given by the Lyapunov exponent of the classical dynamics. For small displacements, we additionally show that, following a short-time Lyapunov decay, the decay freezes well above the ergodic value because of quantum effects. Our analytical results are corroborated by numerical simulations.

  1. Freeze Tolerant Radiator for an Advanced EMU

    NASA Technical Reports Server (NTRS)

    Copeland, Robert J.; Elliott, Jeannine; Weislogel, Mark

    2004-01-01

    During an Extravehicular Activity (EVA), the astronaut s metabolic heat and the heat produced by the Portable Life Support Unit (PLSS) must be rejected. This heat load is currently rejected by a sublimator, which vents up to eight pounds of water each EVA. However, for advanced space missions of the future, water venting to space needs to be minimized because resupply impacts from earth will be prohibitive. If this heat load could be radiated to space from the PLSS, which has enough surface area to radiate most of the heat, the amount of water now vented could be greatly reduced. Unfortunately, a radiator rejects heat at a relatively constant rate, but the astronauts generate a variable heat load depending on how hard they are working. Without a way to vary the heat removal rate, the astronaut would experience cold discomfort or even frostbite. A proven method allowing a radiator to be turned-down is to sequentially allow tubes that carry the heat transfer fluid to the radiator to freeze. A drawback of current freezable radiators using this method is that they are far to heavy for use on a PLSS, because they use heavy construction to prevent the tubes from bursting as they freeze and thaw. This creates the need for a large radiator to reject most of the heat but with a lightweight tube that doesn t burst as it freezes and thaws. The new freezable radiator for the Extravehicular Mobility Unit (EMU) has features to accommodate the expansion of the radiator fluid when it freezes, and still have the high tube to fin conductance needed to minimize the number and weight of the tubes. Radiator fluid candidates are water and a propylene glycol-water mixture. This design maintains all materials within their elastic limits so that large volume changes can be achieved without breaking the tube. This concept couples this elastic expansion with an extremely lightweight, extremely high conductivity carbon fiber fin that can carry the heat needed to thaw a frozen tube. By using most of the exposed surface area of the PLSS as a radiator, the system can reject about 75% of the highest heat load, and reduce the loss of water through sublimation by a factor of four. The proposed radiator and a small water tank can be no heavier than the current system.

  2. Freezing and collapse of flexible polymers

    E-print Network

    Thomas Vogel; Michael Bachmann; Wolfhard Janke

    2009-02-13

    We analyze the freezing and collapse transition of a simple model for flexible polymer chains on simple cubic and face-centered cubic lattices by means of sophisticated chain-growth methods. In contrast to bond-fluctuation polymer models in certain parameter ranges, where these two conformational transitions were found to merge in the thermodynamic limit, we conclude from our results that the two transitions remain well-separated in the limit of infinite chain lengths. The reason for this qualitatively distinct behavior is presumably due to the ultrashort attractive interaction range in the lattice models considered here.

  3. Freezing distributed entanglement in spin chains

    E-print Network

    Irene D'Amico; Brendon W. Lovett; Timothy P. Spiller

    2007-08-21

    We show how to freeze distributed entanglement that has been created from the natural dynamics of spin chain systems. The technique that we propose simply requires single-qubit operations and isolates the entanglement in specific qubits at the ends of branches. Such frozen entanglement provides a useful resource, for example for teleportation or distributed quantum processing. The scheme can be applied to a wide range of systems -- including actual spin systems and alternative qubit embodiments in strings of quantum dots, molecules or atoms.

  4. Freezing on heating of liquid solutions.

    PubMed

    Plazanet, M; Floare, C; Johnson, M R; Schweins, R; Trommsdorff, H P

    2004-09-15

    We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (alpha CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45 degrees and 75 degrees. Quasielastic and elastic neutron scattering show that molecular motions are slowed down in the solid and that crystalline order is established. The solution "freezes on heating." This process is fully reversible, on cooling the solid melts. A rearrangement of hydrogen bonds is postulated to be responsible for the observed phenomenon. PMID:15352791

  5. Freeze fracturing of elastic porous media

    E-print Network

    Vlahou, Ioanna

    2012-06-12

    in polygonal, circular or striped patterns, as seen in Figure 1.2: Exposed ice core of an eroded pingo (Schutter, 2004). 2 1.1 The geophysical problem figure 1.1. The phenomenon is called patterned ground and is a result of a com- bination of several processes... , including particle self-organization and deformation of the soil during freezing (Kessler & Werner, 2003). Other impressive features created by frost heave are pingos. Pingos are mounts with ice-filled cores, sometimes up to tens of metres high and hundreds...

  6. Hierarchical freezing in a lattice model.

    PubMed

    Byington, Travis W; Socolar, Joshua E S

    2012-01-27

    A certain two-dimensional lattice model with nearest and next-nearest neighbor interactions is known to have a limit-periodic ground state. We show that during a slow quench from the high temperature, disordered phase, the ground state emerges through an infinite sequence of phase transitions. We define appropriate order parameters and show that the transitions are related by renormalizations of the temperature scale. As the temperature is decreased, sublattices with increasingly large lattice constants become ordered. A rapid quench results in a glasslike state due to kinetic barriers created by simultaneous freezing on sublattices with different lattice constants. PMID:22400863

  7. Mechano-freezing of the ambient water

    E-print Network

    Zhang, Xi; Zou, Bo; Sun, Chang Q

    2013-01-01

    Raman spectroscopy examination of the 25 deg-C water freezing under compression revealed transition from 1.35 GPa to 0.86 GPa upon ice being formed at continued volume change. The transition is associated with a slight blue shift of the high-frequency phonon (omiga_H ~ 3120 cm-1) and creation of the low-frequency phonons (Omiga_L ~ 200 cm-1). In the liquid and in the solid phase, the increased pressure softens the Omiga_H and stiffens the Omida_L, which indicates the presence of the inter-electron-pair repulsion in both liquid and solid water.

  8. Mechano-freezing of the ambient water

    E-print Network

    Xi Zhang; Tingting Yan; Bo Zou; Chang Q Sun

    2013-10-05

    Raman spectroscopy examination of the 25 deg-C water freezing under compression revealed transition from 1.35 GPa to 0.86 GPa upon ice being formed at continued volume change. The transition is associated with a slight blue shift of the high-frequency phonon (omiga_H ~ 3120 cm-1) and creation of the low-frequency phonons (Omiga_L ~ 200 cm-1). In the liquid and in the solid phase, the increased pressure softens the Omiga_H and stiffens the Omida_L, which indicates the presence of the inter-electron-pair repulsion in both liquid and solid water.

  9. Castration Depression: Affect, Signal Affect, and/or Depressive Illness?

    PubMed

    Fleischer, Les M

    2015-04-01

    The value of Charles Brenner's ideas regarding depression is assessed, focusing on the significance of castration depressive affect. His discussion of whether depression is an affect, a signal affect, or an illness is examined, with special emphasis on his failure to sufficiently address depression as an illness or disorder as defined by psychiatry. Clinical material from the analysis of a man who suffers from severe depression suggests that incorporating psychiatric concepts (biological and pharmacological) with modern conflict theory can be a useful way to understand and treat some patients with depression. Theoretical and clinical controversies associated with combining psychiatric/biological and psychoanalytic views of depression are examined. PMID:25922375

  10. Depression and Insulin Resistance

    PubMed Central

    Pearson, Sue; Schmidt, Mike; Patton, George; Dwyer, Terry; Blizzard, Leigh; Otahal, Petr; Venn, Alison

    2010-01-01

    OBJECTIVE To examine the association between depressive disorder and insulin resistance in a sample of young adults using the Composite International Diagnostic Interview to ascertain depression status. RESEARCH DESIGN AND METHODS Cross-sectional data were collected from 1,732 participants aged between 26 and 36 years. Insulin resistance was derived from blood chemistry measures of fasting insulin and glucose using the homeostasis model assessment method. Those identified with mild, moderate, or severe depression were classified as having depressive disorder. RESULTS The 12-month prevalence of depressive disorder was 5.4% among men and 11.7% among women. In unadjusted models mean insulin resistance was 17.2% (95% CI 0.7–36.0%, P = 0.04) higher in men and 11.4% (1.5–22.0%, P = 0.02) higher in women with depressive disorder. After adjustment for behavioral and dietary factors, the increased level of insulin resistance associated with depressive disorder was 13.2% (?3.1 to 32.3%, P = 0.12) in men and 6.1% (?4.1 to 17.4%, P = 0.25) in women. Waist circumference was identified as a mediator in the relationship between depression and insulin resistance, reducing the ? coefficient in the fully adjusted models in men by 38% and in women by 42%. CONCLUSIONS A positive association was found between depressive disorder and insulin resistance in this population-based sample of young adult men and women. The association seemed to be mediated partially by waist circumference. PMID:20185745

  11. Management of Postpartum Depression

    PubMed Central

    Guille, Constance; Newman, Roger; Fryml, Leah D.; Lifton, Clay K.; Epperson, C. Neill

    2013-01-01

    Postpartum depression, now termed peripartum depression by the DSM-V, is one of the most common complications in the postpartum period and has potentially significant negative consequences for mothers and their families. This article highlights common clinical challenges in the treatment of peripartum depression and reviews the evidence for currently available treatment options. Psychotherapy is the first-line treatment options for women with mild-to-moderate peripartum depression. Antidepressant medication in combination with therapy is recommended for women with moderate-to-severe depression. While pooled case reports and small controlled studies have demonstrated undetectable infant serum levels and no short-term adverse events in infants of mothers breastfeeding while taking sertraline (Zoloft) and paroxetine (Paxil), further research is needed including larger samples and long-term follow-up of infants exposed to antidepressants via breastfeeding with control for maternal depression. Pharmacological treatment recommendations in women who are lactating must include discussion with the patient regarding the benefits of breastfeeding, risks of antidepressant use during lactation and risks of untreated illness. There is a growing evidence base for non-pharmacological interventions including repetitive Transcranial Magnetic Stimulation (rTMS) which may offer an attractive option for women who wish to continue to breastfeed and are concerned about exposure of medication to their infant. Among severe cases of peripartum depression with psychosis referral to a psychiatrist or psychiatric APRN is warranted. Suicidal or homicidal ideation with a desire, intent or plan to harm oneself or anyone one else, including the infant, is a psychiatric emergency, and an evaluation by a mental health professional should be conducted immediately. Peripartum depression treatment research is limited by small samples sizes and few controlled studies. Much work is still needed to better understand which treatments women prefer and are the most effective in ameliorating the symptoms and disease burden associated with peripartum depression. PMID:24131708

  12. Fast hadron freeze-out generator. II. Noncentral collisions

    SciTech Connect

    Amelin, N. S.; Lednicky, R.; Lokhtin, I. P.; Malinina, L. V.; Snigirev, A. M.; Karpenko, Iu. A.; Sinyukov, Yu. M.; Arsene, I.; Bravina, L.

    2008-01-15

    The fast Monte Carlo procedure of hadron generation developed in our previous work is extended to describe noncentral collisions of nuclei. We consider different possibilities to introduce appropriate asymmetry of the freeze-out hypersurface and flow velocity profile. For comparison with other models and experimental data, we demonstrate the results based on the standard parametrizations of the hadron freeze-out hypersurface and flow velocity profile assuming either a common chemical and thermal freeze-out or the chemically frozen evolution from chemical to thermal freeze-out. The C++ generator code is written under the ROOT framework and is available for public use at http://uhkm.jinr.ru/.

  13. A molecular dynamics study of freezing in a confined geometry

    NASA Technical Reports Server (NTRS)

    Ma, Wen-Jong; Banavar, Jayanth R.; Koplik, Joel

    1992-01-01

    The dynamics of freezing of a Lennard-Jones liquid in narrow channels bounded by molecular walls is studied by computer simulation. The time development of ordering is quantified and a novel freezing mechanism is observed. The liquid forms layers and subsequent in-plane ordering within a layer is accompanied by a sharpening of the layer in the transverse direction. The effects of channel size, the methods of quench, the liquid-wall interaction and the roughness of walls on the freezing mechanism are elucidated. Comparison with recent experiments on freezing in confined geometries is presented.

  14. Does the Cryogenic Freezing Process Cause Shorter Telomeres?

    PubMed Central

    Jenkins, Edmund C.; Ye, Lingling; Silverman, Wayne P.

    2012-01-01

    We have observed evidence of increased telomere shortening in short-term T-lymphocyte cultures following freezing and thawing of the original inoculum obtained by ficoll-paque gradient centrifugation, compared to T-lymphocytes that were cultured immediately without freezing and thawing from the same blood sample from 3 female and 3 male adults. Because freezing may have similar effects on other cell types, and because telomere shortening may only manifest its effects after many years or decades, we suggest there is a pressing need for evaluation of the effects of freezing on any cells envisioned for clinical applications, including embryo implantation. PMID:22465657

  15. Reversible Photoinhibition in Antarctic Moss during Freezing and Thawing.

    PubMed Central

    Lovelock, C. E.; Jackson, A. E.; Melick, D. R.; Seppelt, R. D.

    1995-01-01

    Tolerance of antarctic moss to freezing and thawing stress was investigated using chlorophyll a fluorescence. Freezing in darkness caused reductions in Fv/Fm (ratio of variable to maximum fluorescence) and Fo (initial fluorescence) that were reversible upon thawing. Reductions in Fv/Fm and Fo during freezing in darkness indicate a reduction in the potential efficiency of photosystem II that may be due to conformational changes in pigment-protein complexes due to desiccation associated with freezing. The absorption of light during freezing further reduced Fv/Fm and Fo but was also reversible. Using dithiothreitol (DTT), which inhibits the formation of the carotenoid zeaxanthin, we found reduced flurorescence quenching during freezing and reduced concentrations of zeaxanthin and antheraxanthin after freezing in DTT-treated moss. Reduced concentrations of zeaxanthin and antheraxanthin in DTT-treated moss were partially associated with reductions in nonphotochemical fluorescence quenching. The reversible photoinhibition observed in antarctic moss during freezing indicates the existence of processes that protect from photoinhibitory damage in environments where freezing temperatures occur in conjunction with high solar radiation levels. These processes may limit the need for repair cycles that require temperatures favorable for enzyme activity. PMID:12228644

  16. Design of a blood-freezing system for leukemia research

    NASA Technical Reports Server (NTRS)

    Williams, T. E.; Cygnarowicz, T. A.

    1978-01-01

    Leukemia research involves the use of cryogenic freezing and storage equipment. In a program being carried out at the National Cancer Institute (NCI), bone marrow (white blood cells) was frozen using a standard cryogenic biological freezer. With this system, it is difficult to maintain the desired rate of freezing and repeatability from sample to sample. A freezing system was developed that satisfies the requirements for a repeatable, constant freezing rate. The system was delivered to NIC and is now operational. This report describes the design of the major subsystems, the analyses, the operating procedure, and final system test results.

  17. A Holistic Description of Immersion Freezing of Water and Aqueous Solution Droplets Using a Water Activity Based Model

    NASA Astrophysics Data System (ADS)

    Knopf, D. A.; Alpert, P. A.

    2013-12-01

    Immersion freezing of water and aqueous solutions by particles acting as ice nuclei (IN) is a common process of heterogeneous ice nucleation in the atmosphere where it results in the glaciation of mixed-phase and cirrus clouds. Using a variety of IN types suspended in various aqueous solutions and pure water, we find that immersion freezing temperatures and kinetics can be described solely by temperature, T, and solution water activity, aw, which is the ratio of the vapor pressure of the solution and the saturation water vapor pressure under the same conditions and, in equilibrium, is equivalent to relative humidity (RH). This allows the freezing point and corresponding heterogeneous ice nucleation rate coefficient, Jhet, to be uniquely expressed by T and aw, a result termed the aw based immersion freezing model (ABIFM). This method is independent of the nature of the solute, applicable for pure water droplet freezing which is significant for mixed-phase cloud formation, and accounts for several varying parameters, including cooling rate and IN surface area, while providing a holistic description of immersion freezing capable of predicting of freezing temperatures, Jhet, frozen fractions, ice particle production rates and numbers. Our findings are based on experimental freezing data collected for various IN surface areas and cooling rates of droplets containing marine biogenic material, two soil humic acids, four mineral dusts, and one organic monolayer acting as IN. For all investigated IN types we demonstrate that droplet freezing temperatures increase as IN surface area increases. Similarly, droplet freezing temperatures increase as the cooling rate decreases. The experimental data implicitly questions the common notion that one active site initiates the formation of an ice embryo leading to the crystallization of the aqueous phase. The log10(Jhet) values for the various IN types derived exclusively by T and aw, provide a complete description of the heterogeneous ice nucleation kinetics. Thus, the ABIFM can be applied over the entire range of T, RH, total IN surface area, and cloud activation timescales typical of atmospheric conditions. Lastly, we demonstrate that ABIFM can be used to derive frozen fractions of droplets and ice particle production for atmospheric models of cirrus and mixed phase cloud conditions.

  18. Prevalence of Depression in Patients With Hypertension

    PubMed Central

    Li, Zhanzhan; Li, Yanyan; Chen, Lizhang; Chen, Peng; Hu, Yingyun

    2015-01-01

    Abstract Prevalence estimates of depression in hypertensive patients varied widely in existing studies. We conducted a systematic review and meta-analysis of observational studies to summarize the point prevalence of depressive symptoms in adults with hypertension. Comprehensive electronic searches of PubMed, Web of Knowledge, China National Knowledge Internet (CNKI), Wangfang, and Weipu databases were conducted to identify any study in each database published from initial state to November 31, 2014, reporting the prevalence of depression in hypertensive patients. Random-effects model was used to estimate the prevalence of depressive symptoms. We also limited the analyses to studies using clinical interview and prespecified criteria for diagnosis. All statistical calculations were made by using the Stata Version 12.0 (College Station, TX) and Statsdirect Version 2.7.9. We identified 41 studies with a total population of 30,796 in the present meta-analysis. The summarized prevalence of depression among hypertensive patients is 26.8% (95% confidence interval (CI): 21.7%–32.3%). Subgroup analysis shows the following results: for male 24.6%, 95% CI: 14.8%–35.9%, for female 24.4%, 95% CI: 14.6%–35.8%. For China: 28.5% (95% CI: 22.2%–35.3%); for other region (22.1%, 95% CI: 12.1%–34.1%); for community: 26.3% (95% CI: 17.7%–36.0%), for hospital: 27.2% (95% CI: 20.6%–34.5%). Estimated prevalence by interview was 21.3% (95% CI: 14.2%–30.0%); prevalence of depressive symptoms adjudicated by self-rating scales was 29.8% (95% CI: 23.3%–36.7%). The observed heterogeneity in depression prevalence of hypertension may be attributed to differences in method of evaluation. Self-report scales should be cautious of estimating the presence of depression. Thus, interview-defined depression affects approximately one third of hypertensive patients. Effective interventions for depression on patient-centered are needed. PMID:26252317

  19. Interplay between demixing and freezing in two-dimensional symmetrical mixtures.

    PubMed

    Patrykiejew, A; Soko?owski, S

    2010-01-01

    The interplay between demixing and freezing in two-dimensional symmetrical binary mixtures of Lennard-Jones particles is studied using Monte Carlo simulation. It is demonstrated that different scenarios are possible. For example, the line of continuous liquid demixing transition can start at the liquid side of the vapor-liquid coexistence at the lower critical end point and then it can terminate at the liquid side of the liquid-demixed solid coexistence at the upper critical end point. Other situations are also possible. We distinguish four different scenarios depending on the interactions between unlike particles. PMID:20365417

  20. The impact of freeze-drying on microstructure and rehydration properties of carrot Adrian Voda a,

    E-print Network

    van Vliet, Lucas J.

    The impact of freeze-drying on microstructure and rehydration properties of carrot Adrian Voda a Microstructure Winter carrot Freeze-drying The impact of freeze-drying, blanching and freezing rate pre techniques. The freezing rate determines the size of ice crystals being formed that leave pores upon drying

  1. INTRODUCTION Cold-hardy invertebrates can be classified most simply as freeze

    E-print Network

    Lee Jr., Richard E.

    524 INTRODUCTION Cold-hardy invertebrates can be classified most simply as freeze tolerant or freeze intolerant. Freeze-tolerant species survive the freezing of their body fluids by promoting ice (Zachariassen, 1985; Duman et al., 1991; Lee, 1991). For freeze-intolerant species, by contrast, internal ice

  2. Continuous freezing condenser for phthalic anhydride. [Patented

    SciTech Connect

    Korobchanskii, V.I.; Grebenyuk, A.F.; Korobchanskii, Yu.V.; Il'in, A.P.

    1981-01-01

    The increasing outputs of plastics and polymer materials necessitate correspondingly larger outputs of various organic monomers. Phthalic anhydride is one of the source products for organic synthesis. Phthalic anhydride is made in the coking industry by the catalytic vapor-phase oxidation of naphthalene. The product is difficult to isolate from the reaction mixture leaving the static-bed catalytic reactors, since the volume of gases and vapors to be cooled is very large and the phthalic anhydride concentration in the mixture is very low. Continuous freezing condensers have been developed, in which the gas stream is cooled by counterflow contact with a stream of solid granular material on which the phthalic anhydride is condensed. One serious drawback is the need to expend large amounts of heat to remelt the phthalic anhydride crystals. The low strength of the granulated solid substrate leads to dust formation in operation, and the dust contaminates the product. We have developed a condenser in which the freezing and remelting stages take place on metal balls in the same unit and the heat is derived from the incoming reaction mixture. Accordingly, units of large capacity can be constructed giving a higher product yield and lowering the heat consumption in the remelting stage.

  3. Fundamental Boiling and RP-1 Freezing Experiments

    NASA Technical Reports Server (NTRS)

    Goode, Brian; Turner, Larry D. (Technical Monitor)

    2001-01-01

    This paper describes results from experiments performed to help understand certain aspects of the MC-1 engine prestart thermal conditioning procedure. The procedure was constrained by the fact that the engine must chill long enough to get quality LOX at the LOX pump inlet but must be short enough to prevent freezing of RP-1 in the fuel pump. A chill test of an MC-1 LOX impeller was performed in LN2 to obtain data on film boiling, transition boiling and impeller temperature histories. The transition boiling data was important to the chill time so a subsequent experiment was performed chilling simple steel plates in LOX to obtain similar data for LOX. To address the fuel freezing concern, two experiments were performed. First, fuel was frozen in a tray and its physical characteristics were observed and temperatures of the fuel were measured. The result was physical characteristics as a function of temperature. Second was an attempt to measure the frozen thickness of RP-1 on a cold wall submerged in warm RP-1 and to develop a method for calculating that thickness for other conditions.

  4. Deception as treatment: the case of depression.

    PubMed

    Blease, Charlotte

    2011-01-01

    Is it ever right to prescribe placebos to patients in clinical practice? The General Medical Council is ambivalent about the issue; the American Medical Association asserts that placebos can be administered only if the patient is (somehow) 'informed'. The potential problem with placebos is that they may involve deception: indeed, if this is the case, an ethical tension arises over the patient's autonomy and the physician's requirement to be open and honest, and the notion that medical care should be the primary concern. This paper examines the case of depression as an entry point for understanding the complexities of the prescription of placebos. Recent important meta-analyses of antidepressants claim that they are not significantly more effective in a clinical setting than placebos. Given that antidepressants have numerous adverse side effects and are hugely expensive, this provocative research has serious potential ethical and practical implications for patients and medical providers. Should placebos be prescribed in place of antidepressants? The case of depression highlights another important issue which medical ethical codes have hitherto overlooked: well-being is not synonymous with being realistic about oneself, one's circumstances and the future. While severely depressed individuals are unduly pessimistic about themselves and the world around them, treatment of depressed individuals can be deemed successful when patients have successfully attained those positive illusions that are indicative of psychological health. This is exactly what successful psychological treatments of depression seem to achieve. It is therefore possible that there may be a limited unavoidable role for deception in medicine. PMID:20962066

  5. Thermal conductivity measurements in phase change materials under freezing in presence of nanoinclusions

    NASA Astrophysics Data System (ADS)

    Angayarkanni, S. A.; Philip, John

    2015-09-01

    We study the thermal properties and internal microstructures of n-hexadecane alkane containing nanoinclusions of copper nanowire, multi walled carbon nanotube, and graphene nanoplatelets of different volume fractions. Just below the freezing point, a large thermal contrast is observed in all the three systems. The thermal conductivity decreases with temperature below the freezing temperature and stabilizes at ˜10 °C below the freezing point. More than 100% of thermal conductivity enhancement is observed with 0.01 wt. % of nanofillers during the liquid to solid phase change. It is speculated that the reduction in the interfacial thermal resistance and the internal stress generated during the first order phase transition, due to the presence of nanoinclusions at grain boundaries of alkane crystals, led to the observed increase in the thermal conductivity. We found that an optimal nanoparticle loading with the space filling agglomerates in a phase change alkane can provide an extremely large thermal conductivity. Though the thermal conductivity enhancement at higher particle loading was independent of the bulk thermal conductivity of dispersed nanomaterials, an anomalously large thermal contrast is observed at a very low concentration in copper nanowire suspension. These results provide new approaches to achieve large thermal storage in organic phase change materials.

  6. Caregiving and Depression

    MedlinePLUS

    ... away. Yet, researchers found that even three years after the death of a spouse with dementia, some former caregivers continued to experience depression and loneliness. In an effort to return their life to normal, former caregivers may need to seek ...

  7. Depression in glioma 

    E-print Network

    Rooney, Alasdair Grant

    2011-11-25

    BACKGROUND Few high-quality observational studies have been conducted to examine clinically relevant features of emotional distress and Major Depressive Disorder (MDD) in adults with primary cerebral glioma. Our knowledge ...

  8. Neuroinflammation, neurodegeneration, and depression.

    PubMed

    Hurley, Laura L; Tizabi, Yousef

    2013-02-01

    Neurodegeneration and depression are two common co-morbid conditions, particularly within the aging population. Research has linked neuroinflammation as a major contributing factor to both of these diseases. The key to neuroinflammation effects on neurodegeneration and depression appears to lie within the dysregulation of the control and release of pro- and anti-inflammatory cytokines. This can come from an internal or external insult to the system, or from changes in the individual due to aging that culminate in immune dysregulation. The need to reduce neuroinflammation has led to extensive research into neuroprotectants. We discuss the efficacy found with nicotine, alcohol, resveratrol, curcumin, and ketamine. Our main focus will be on what research tells us about the connections between neuroinflammation, neurodegeneration, and depression, and the hope that neuroprotectants research gives people suffering from neurodegeneration and depression stemming from neuroinflammation. We will conclude by making suggestions for future research in this area. PMID:22895696

  9. Treating Major Depressive Disorder

    MedlinePLUS Videos and Cool Tools

    ... health news that matters to you. Related MedlinePlus Health Topics Depression About MedlinePlus Site Map FAQs Contact ... Rockville Pike, Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page ...

  10. Adjustments and Depression

    MedlinePLUS Videos and Cool Tools

    ... 10 Questions (PDF) - Spanish Consortium for Spinal Cord Medicine, Clinical Practice Guidelines The Guidelines, available at no ... 1-800-273-TALK (8255). National Library of Medicine Discussion of depression and treatment options. The Spinal ...

  11. Depression during pregnancy - alert.

    PubMed

    2015-10-28

    Urgent investment in mental health services for maternity units is being called for because a study revealed that as many as 250,000 pregnant women a year in the UK could experience depression. PMID:26508222

  12. Inflammation and depression.

    PubMed

    Zunszain, Patricia A; Hepgul, Nilay; Pariante, Carmine M

    2013-01-01

    Major depressive disorder (MDD) is a complex illness and it is likely that alterations in several interacting systems underlie its pathogenesis. Numerous hypotheses have been proposed to elucidate its origins. The inflammatory hypothesis emphasises the role of psycho-neuroimmunological dysfunctions. This is based on several observations: subsets of MDD patients have an altered peripheral immune system, with impaired cellular immunity and increased levels of proinflammatory cytokines; cytokines can influence neurotransmitter metabolism, neuroendocrine function and regional brain activity, all of which are relevant to depression; acute administration of cytokines causes sickness behaviour which shares features with depression, and patients undergoing cytokine treatment develop depressive symptoms. In this chapter, we discuss the evidence linking inflammation and MDD, looking at data from clinical and animal studies, the role of stress, possible mechanisms and the involvement of genetic polymorphisms. Further understanding of pathways involved is still needed. This will be vital for the identification of new drug targets and preventative strategies. PMID:22553073

  13. The Pathophysiology of Depression

    PubMed Central

    Aldous, N. Ronald; Mann, Alan M.

    1963-01-01

    The conceptual difficulties in the diagnosis of depression, and the study of affect generally, hinder a clear approach to the “organic” side of depressive illness. While autonomic, biochemical and electrophysiological disturbances follow a general pattern in severe retarded depressions, correlation of these with the variable somatic symptomatology is only partial and demarcation from other psychiatric syndromes vague. Various attempts have been made to relate the patterns of autonomic reaction to thought content on the one hand and to central nervous system activity and organization on the other. In recent years, fragments of knowledge about physiological changes accompanying affective experiences in infancy have appeared. Isolated descriptions of what appears to have been the replacement of depression by somatic symptoms with or without somatic pathology have not yet been organized into a coherent whole. In this article the various studies and opinions relevant to the above conclusions have been reviewed and the findings discussed. PMID:14052978

  14. Validation studies of a computational model for molten material freezing

    SciTech Connect

    Sawada, Tetsuo; Ninokata, Hisashi; Shimizu, Akinao

    1996-02-01

    Validation studies are described of a computational model for the freezing of molten core materials under core disruptive accident conditions of fast breeder reactors. A series of out-of-pile experiments named SIMBATH, performed at Forschungszentrum Karlsruhe in Germany, has already been analyzed with the SIMMER-II code. In the current study, TRAN simulation tests in the SIMBATH facility are analyzed by SIMMER-II for its modeling validation of molten material freezing. The original TRAN experiments were performed at Sandia National laboratories to examine the freezing behavior of molten UO{sub 2} injected into an annular channels. In the TAN simulation experiments of the SIMBATH series, similar freezing phenomena are investigated for molten thermite, a mixture of Al{sub 2}O{sub 3} and iron, instead of UO{sub 2}. Two typical TRAN simulation tests are analyzed that aim at clarification of the applicability of the code to the freezing process during the experiments. The distribution of molten materials that are deposited in the test section according to the experimental measurements and in calculations by SIMMER-II is compared. These studies confirm that the conduction-limited freezing model combined with the rudimentary bulk freezing (particle-jamming) model of SIMMER-II is compared. These studies confirm that the conduction-limited freezing model combined with the rudimentary bulk freezing (particle-jamming) model of SIMMER-II could be used to reproduce the TRAN simulation experiments satisfactorily. This finding encourages the extrapolation of the results of previous validation research for SIMMER-II based on other SIMBATH tests to reactor case analyses. The calculation by SIMMER-II suggest that further improvements of the model, such as freezing on a convex surface of pin cladding and the scraping of crusts, make possible more accurate simulation of freezing phenomena.

  15. [Depression and culture].

    PubMed

    Stompe, Thomas; Ritter, Kristina; Schrank, Beate

    2009-01-01

    It is well established knowledge that, aside from biological and biographical factors, socio-cultural patterns have a major impact in prevalence and phenomenology of depressive disorders. It is the aim of the authors (1) to clarify the different epistemological positions of transcultural research in depression, (2) to present the most important findings of this research, (3) to develop suggestions for culture-sensitive epidemiological research. PMID:19909697

  16. Freezing of a two dimensional fluid in to a crystalline phase : Density functional approach

    E-print Network

    Anubha Jaiswal; Swarn L. Singh; Yashwant Singh

    2012-10-02

    A free-energy functional for a crystal proposed by Singh and Singh (Europhys. Lett. {\\bf {88}}, 16005 (2009)) and which contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the crystallization of a two-dimensional fluid. The results found for fluids interacting via the inverse power potential $ u(r)= \\epsilon ({\\sigma}/{r})^{n} $ for n= 3, 6 and 12 are in good agreement with experimental and simulation results. The contribution made by the symmetry broken part to the grand thermodynamic potential at the freezing point is found to increase with the softness of the potential. Our results explain why the Ramakrishnan-Yussouff (Phys. Rev. B {\\bf 19}, 2775 (1979)) free-energy functional gave good account of freezing transitions of hard-core potentials but failed for potentials that have soft core and/or attractive tail.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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.

  18. Multiscale model of a freeze-thaw process for tree sap exudation

    E-print Network

    Graf, Isabell; Stockie, John M

    2015-01-01

    Sap transport in trees has long fascinated scientists, and a vast literature exists on experimental and modelling studies of trees during the growing season when large negative stem pressures are generated by transpiration from leaves. Much less attention has been paid to winter months when trees are largely dormant but nonetheless continue to exhibit interesting flow behaviour. A prime example is sap exudation, which refers to the peculiar ability of sugar maple (Acer saccharum) and related species to generate positive stem pressure while in a leafless state. Experiments demonstrate that ambient temperatures must oscillate about the freezing point before significantly heightened stem pressures are observed, but the precise causes of exudation remain unresolved. The prevailing hypothesis attributes exudation to a physical process combining freeze-thaw and osmosis, which has some support from experimental studies but remains a subject of active debate. We address this knowledge gap by developing the first math...

  19. [Effect of freezing and cooking on the texture and electrophoretic pattern of the proteins of octopus arms (Octopus vulgaris)].

    PubMed

    Reyes, Genara; Nirchio, Mauro; Bello, Rafael; Borderías, Javier

    2014-09-01

    Texture is the most valuable feature in cephalopods. Factors that mainly affect the texture of octopus are: freezing, scalding and cooking. The aim of this study was to assess the effect of freezing, scalding and length of cooking time on the texture and electrophoretic pattern of proteins of octopus arms. Octopuses were trapped near Margarita Island and carried with ice to the laboratory where they were packed and subjected to: a) freezing at -27 degrees C or at -20 degrees C b) scalding c) cooking for 25 min, 35 min or 45 min. Shear force was determined by Kramer cell on strips of octopus arms. SDS-PAGE was done according to the Laemmli method with 12% polyacrilamide gels. A sensory evaluation of the preference of texture was carried out using a hedonic scale of 7-points and a non-trained panel. Octopus texture was not affected by freezing temperature or scalding. Frozen octopus was softer after cooking than fresh. The longer the cooking time was, the softer the octopus was. Myosin heavy chain (MHC) was not significantly affected by scalding or cooking; however large aggregates heavier than MHC, new bands and loss of resolution of the bands appeared. Myosin and paramyosin bands were more affected by freezing prior to cooking. PMID:26137796

  20. Transition from Baryon- to Meson-Dominated Freeze Out -- Early Decoupling around 30 A GeV?

    E-print Network

    H. Oeschler; J. Cleymans; K. Redlich; S. Wheaton

    2007-01-26

    The recently discovered sharp peak in the excitation function of the K+/pi+ ratio around 30 A GeV in relativistic heavy-ion collisions is discussed in the framework of the Statistical Model. In this model, the freeze-out of an ideal hadron gas changes from a situation where baryons dominate to one with mainly mesons. This transition occurs at a temperature T = 140 MeV and baryon chemical potential mu(B) = 410 MeV corresponding to an energy of sqrt(s) = 8.2 GeV. The calculated maximum in the K+/pi+ ratio is, however, much less pronounced than the one observed by the NA49 Collaboration. The smooth increase of the K-/pi- ratio with incident energy and the shape of the excitation functions of the Lambda/pi+, Xi-/pi+ and Omega/pi ratios all exhibiting maxima at different incident energies, is consistent with the presently available experimental data. The measured K+/pi+ ratio exceeds the calculated one just at the incident energy when the freeze-out condition is changing. We speculate that at this point freeze-out might occur in a modified way. We discuss a scenario of an early freeze-out which indeed increases K+/pi+ ratio while most other particle ratios remain essentially unchanged. Such an early freeze-out is supported by results from HBT studies.

  1. Emerging from Depression: Treatment of Adolescent Depression Using the Major Treatment Models of Adult Depression.

    ERIC Educational Resources Information Center

    Long, Kathleen M.

    Noting that adolescents who commit suicide are often clinically depressed, this paper examines various approaches in the treatment of depression. Major treatment models of adult depression, which can be directly applied to the treatment of the depressed adolescent, are described. Major treatment models and selected research studies are reviewed in…

  2. Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

    SciTech Connect

    Gomez, A.; Villanueva, R.; Vie, D.; Murcia-Mascaros, S.; Martinez, E.; Beltran, A.; Sapina, F.; Vicent, M.; Sanchez, E.

    2013-01-15

    Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10-15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition, Rietveld refinement of the XRD profiles of selected samples allows detecting the coexistence of the tetragonal and the cubic phases for high doping concentration and high thermal treatment temperatures. Raman experiments suggest the presence of both phases also at relatively low treatment temperatures. - Graphical abstract: Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders by thermal decomposition of precursors obtained by freeze-drying, and this synthetic procedure has been scaled up to the 100 g scale. Highlights: Black-Right-Pointing-Pointer Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders. Black-Right-Pointing-Pointer The synthetic method involves the thermal decomposition of precursors obtained by freeze-drying. Black-Right-Pointing-Pointer The temperature of the thermal treatment controls particle sizes. Black-Right-Pointing-Pointer The preparation procedure has been scaled up to the 100 g scale. Black-Right-Pointing-Pointer This method is appropriate for the large-scale industrial preparation of multimetallic systems.

  3. How Important Is Intrinsic Spirituality in Depression Care?

    PubMed Central

    Cooper, Lisa A; Brown, Charlotte; Thi Vu, Hong; Ford, Daniel E; Powe, Neil R

    2001-01-01

    We used a cross-sectional survey to compare the views of African-American and white adult primary care patients (N = 76) regarding the importance of various aspects of depression care. Patients were asked to rate the importance of 126 aspects of depression care (derived from attitudinal domains identified in focus groups) on a 5-point Likert scale. The 30 most important items came from 9 domains: 1) health professionals' interpersonal skills, 2) primary care provider recognition of depression, 3) treatment effectiveness, 4) treatment problems, 5) patient understanding about treatment, 6) intrinsic spirituality, 7) financial access, 8) life experiences, and 9) social support. African-American and white patients rated most aspects of depression care as similarly important, except that the odds of rating spirituality as extremely important for depression care were 3 times higher for African Americans than the odds for whites. PMID:11556945

  4. Geoff Freeze is a Principal Member of the Technical Staff at Sandia National Laboratories in Albuquerque, New Mexico. Mr. Freeze has over 25

    E-print Network

    Biography G. Freeze Geoff Freeze is a Principal Member of the Technical Staff at Sandia National Laboratories in Albuquerque, New Mexico. Mr. Freeze has over 25 years of professional experience in radioactive techniques. Mr. Freeze has authored over 40 journal articles and project reports, taught short courses

  5. Freezing of HNO{sub 3}/H{sub 2}SO{sub 4}/H{sub 2}O solutions at stratospheric temperatures: Nucleation statistics and experiments

    SciTech Connect

    Koop, T.; Luo, B.; Biermann, U.M.; Crutzen, P.J.; Peter, T.

    1997-02-06

    Calorimetric freezing experiments with aqueous sulfuric and nitric acid solutions are presented and applied to the formation of polar stratospheric clouds (PSCs). We show that the nucleation of hydrates from these solutions is a stochastic process and that nucleation rates and their uncertainties can be determined using Poisson statistics. Under thermodynamic equilibrium conditions above the ice frost point, the homogeneous nucleation rates of stratospheric aerosols are exceedingly low, ruling out homogeneous freezing as a pathway for PSC formation. Several stratospherically important substrates were tested concerning their ability to induce heterogeneous nucleation. None of the experiments indicated a relevant enhancement of the freezing probability of liquid aerosols. Moreover, the experiments reveal that the freezing process of the solutions under stratospheric conditions is limited by the nucleation rates of the hydrates, rather than their crystal growth rates, thus ruling out the possibility of a glassy state of stratospheric aerosol droplets. Also, we argue why a glacial state of the aerosols seems to be unlikely. The only processes leading to freezing of the hydrates appear to be the heterogeneous nucleation on water ice crystals forming below the frost point and the homogeneous freezing of almost binary HNO{sub 3}/H{sub 2}O droplets with H{sub 2}SO{sub 4} concentrations below approximately 0.01 wt%. 68 refs., 18 figs., 4 tabs.

  6. Understanding freeze stress in biological tissues: thermodynamics of interfacial water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A thermodynamic approach to distinguish forms of freeze energy that injure plants as the temperature decreases is developed. The pattern resulting from this analysis dictated the sequence of thermal requirements for water to exist as an independent state. Improvement of freezing tolerance in biolo...

  7. 7 CFR 58.638 - Freezing the mix.

    Code of Federal Regulations, 2010 CFR

    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... Procedures § 58.638 Freezing the mix. After the mix enters the freezer, it shall be frozen as rapidly...

  8. Logistic Regression Analysis of Freezing Tolerance in Winter Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four winter wheat cultivars, Eltan, Froid, Kestrel, and Tiber, were cold-acclimated for five weeks and then tested for freezing tolerance in a programmable freezer. The temperature of the soil was recorded every two minutes and the freezing episode was described as five parameters: the minimum temp...

  9. Generalized motor inhibitory deficit in Parkinson's disease patients who freeze.

    PubMed

    Bissett, Patrick G; Logan, Gordon D; van Wouwe, Nelleke C; Tolleson, Christopher M; Phibbs, Fenna T; Claassen, Daniel O; Wylie, Scott A

    2015-12-01

    Freezing of gait is a disabling symptom of Parkinson's disease (PD) that involves failure to initiate and continue motor activity appropriately. PD disrupts fronto-basal ganglia circuitries that also implement the inhibition of responses, leading to the hypothesis that freezing of gait may involve fundamental changes in both initiation and inhibition of motor actions. We asked whether PD patients who show freezing of gait show selective deficits in their ability to inhibit upper and lower extremity reactions. We compared older healthy controls, older PD controls without freezing of gait, and older PD participants with freezing of gait, in stop-signal tasks that measured the initiation (go trials) and inhibition (stop trials) of both hand and foot responses. When only go trials were presented, all three groups showed similar initiation speeds across lower and upper extremity responses. When stop-signal trials were introduced, both PD groups slowed their reactions nearly twice as much as healthy controls. While this adjustment helped PD controls stop their actions as quickly as healthy controls, PD patients with freezing showed significantly delayed inhibitory control of both upper and lower extremities. When anticipating the need to stop their actions urgently, PD patients show greater adjustments (i.e., slowing) to reaction speed than healthy controls. Despite these proactive adjustments, PD patients who freeze show marked impairments in inhibiting both upper and lower extremity responses, suggesting that freezing may involve a fundamental disruption to the brain's inhibitory control system. PMID:26354102

  10. Effects of Refrigeration and Freezing on the Electromechanical and

    E-print Network

    Buschmann, Michael

    Effects of Refrigeration and Freezing on the Electromechanical and Biomechanical Properties, or during a single freeze-thaw cycle at 20°C were examined in young bovine cartilage. Non-destructive elec.0% of control values, p 0.004) were observed at day 12 of refrigeration at 4°C, but no significant changes were

  11. 40 CFR 52.1135 - Regulation for parking freeze.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... conform to the requirements of 40 CFR 51.4(b); and the agency rules or procedures may provide that if no... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Regulation for parking freeze. 52.1135... for parking freeze. (a) Definitions: (1) The phrase to commence construction means to engage in...

  12. Using infrared thermography to study freezing in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Factors that determine when and to what extent a plant will freeze are complex. While thermocouples have served as the main method of monitoring the freezing process in plants, infrared thermography offers distinct advantages, and the use of this latter technology has provided new insights on the p...

  13. 40 CFR 52.1135 - Regulation for parking freeze.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... conform to the requirements of 40 CFR 51.4(b); and the agency rules or procedures may provide that if no... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Regulation for parking freeze. 52.1135... for parking freeze. (a) Definitions: (1) The phrase to commence construction means to engage in...

  14. Freeze Out Process with In-Medium Nucleon Mass

    E-print Network

    Sven Zschocke; Laszlo P. Csernai; Etele Molnár; Jaakko Manninen; Agnes Nyiri

    2006-10-16

    We investigate the kinetic freeze out scenario of a nucleon gas through a finite layer. The in-medium mass modification of nucleons and it's impact on the freeze out process is studied. A considerable modification of the thermodynamical parameters temperature, flow-velocity, energy density and particle density has been found in comparison with evaluations which use a constant vacuum nucleon mass.

  15. 40 CFR 52.1135 - Regulation for parking freeze.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... conform to the requirements of 40 CFR 51.4(b); and the agency rules or procedures may provide that if no... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Regulation for parking freeze. 52.1135... for parking freeze. (a) Definitions: (1) The phrase to commence construction means to engage in...

  16. Determination of Freeze-out Conditions from Lattice QCD Calculations

    E-print Network

    Frithjof Karsch

    2012-02-19

    Freeze-out conditions in Heavy Ion Collisions are generally determined by comparing experimental results for ratios of particle yields with theoretical predictions based on applications of the Hadron Resonance Gas model. We discuss here how this model dependent determination of freeze-out parameters may eventually be replaced by theoretical predictions based on equilibrium QCD thermodynamics.

  17. 40 CFR 52.1135 - Regulation for parking freeze.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... conform to the requirements of 40 CFR 51.4(b); and the agency rules or procedures may provide that if no... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Regulation for parking freeze. 52.1135... for parking freeze. (a) Definitions: (1) The phrase to commence construction means to engage in...

  18. 40 CFR 52.1135 - Regulation for parking freeze.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... conform to the requirements of 40 CFR 51.4(b); and the agency rules or procedures may provide that if no... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Regulation for parking freeze. 52.1135... for parking freeze. (a) Definitions: (1) The phrase to commence construction means to engage in...

  19. 7 CFR 305.18 - Quick freeze treatment schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Quick freeze treatment schedule. 305.18 Section 305.18 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Quick Freeze Treatments § 305.18 Quick...

  20. Prospective Primary School Teachers' Perceptions on Boiling and Freezing

    ERIC Educational Resources Information Center

    Senocak, Erdal

    2009-01-01

    The aim of this study was to investigate the perceptions of prospective primary school teachers on the physical state of water during the processes of boiling and freezing. There were three stages in the investigation: First, open-ended questions concerning the boiling and freezing of water were given to two groups of prospective primary school…

  1. Freezing-induced perturbation of tertiary structure of monoclonal antibody

    E-print Network

    Liu, Lu; Kueltzo, L. A.; Jones, L. S.; Carpenter, J. F.

    2006-10-25

    field-flow fractionation(AFFF) stud- ies of the freeze-thawed samples showed that IgG aggregates formed during freeze-thawing at pH 3, 4 and 8 either with or with- out 150 mM KCl. KCl facilitated aggregation at pH 3, but reduce it at pH 4...

  2. Effects of freezes on survival of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus in Florida is occasionally subjected to freezing temperatures. No information was available on the effect of freezing temperatures on mortality of Asian citrus psyllid (Diaphorina citri) in Florida. Studies were therefore initiated to assess mortality rates of D. citri eggs, nymphs and adults...

  3. 47 CFR 64.1190 - Preferred carrier freezes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...telecommunications services (e.g. , local exchange, intraLATA toll, and interLATA toll) subject to a preferred carrier freeze. The carrier...freeze orders electronically shall establish one or more toll-free telephone numbers exclusively for that...

  4. Stopping biological time: The freezing of living cells

    SciTech Connect

    Mazur, P.

    1987-01-01

    The fundamental physical-chemical events that occur during the freezing and thawing of cells are outlined and the manner in which cell permeability determines the response of the cell to freezing is discussed both in terms of physical response and in terms of survival. 40 refs., 12 figs.

  5. Observation of a freezing drizzle episode: A case study

    NASA Astrophysics Data System (ADS)

    Fernández-González, S.; Valero, F.; Sanchez, Jose L.; Gascón, E.; López, L.; García-Ortega, E.; Merino, A.

    2014-11-01

    On 5 February 2012 an episode of freezing precipitation took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This precipitation affected high elevations, where temperatures remained below freezing because of snow cover that had accumulated from snowfall during the previous days. The case study was recorded by surface synoptic observations (SYNOP) at Navacerrada Pass meteorological observatory (belonging to the National Weather Service of Spain). To study winter cloud systems during the TEcoAgua project, a multichannel ground-based microwave radiometer (MMWR), Micro Rain Radar (MRR-2), and isothermal cloud chamber were installed in the study area, thus permitting the monitoring of the freezing precipitation event. Analysis using Meteosat Second Generation (MSG) satellite data and observations permitted the determination of factors that triggered the freezing precipitation event. Freezing drizzle was interspersed with the passage of a warm and cold front. During frontal passage, mid-level clouds inhibited the generation of freezing drizzle, with snowfall recorded in the study area. However, during the period between the two fronts, an absence of mid-level clouds permitted low-level orographic clouds to persist upwind of the mountain system, producing freezing drizzle at the surface. The decisive factors for the generation of freezing drizzle were high humidity at low levels, weak mesoscale updrafts caused by the topography, stability at mid levels, cloud-top temperatures warmer than - 15 °C, and low concentrations of ice nuclei.

  6. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze...

  7. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze...

  8. St. Lawrence River Freeze-Up Forecast Procedure.

    ERIC Educational Resources Information Center

    Assel, R. A.

    A standard operating procedure (SOP) is presented for calculating the date of freeze-up on the St. Lawrence River at Massena, N.Y. The SOP is based on two empirical temperature decline equations developed for Kingston, Ontario, and Massena, N.Y., respectively. Input data needed to forecast freeze-up consist of the forecast December flow rate and…

  9. Clarification on Mechanical Characteristic in State of Stress of Osteoarthritis of the Hip Joint Using Stress Freezing Method

    NASA Astrophysics Data System (ADS)

    Maezaki, Nobutaka; Ezumi, Tsutomu; Hachiya, Masashi

    In this research, the Osteoarthritis of Hip Joint was pick up, the 3-dimensional stress freezing method of photoelastic method was applied, and the state of the stress in the normality hip joint and the transformable hip joint was examined. The direction and the singular point of principal stress and stress distribution were experimentally examined. At result, The Osteoarthritis of Hip Joint touches by 2 points, Osteoarthritis of Hip Joint occurrence of the new singular point with flat of the femoral head, They change the direction of the principal stress line in an existing singular point is cause.

  10. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25.1455 Aeronautics... § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained overboard in flight or...

  11. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25.1455 Aeronautics... § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained overboard in flight or...

  12. Alternative overwintering strategies in an Antarctic midge: freezing vs. cryoprotective dehydration

    E-print Network

    Lee Jr., Richard E.

    Alternative overwintering strategies in an Antarctic midge: freezing vs. cryoprotective dehydration understanding of freeze avoidance strategies employed by polar invertebrates. Although the underlying cellular processes associated with this strategy are similar to those of freeze tolerance, little is known about

  13. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25.1455 Aeronautics... § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained overboard in flight or...

  14. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25.1455 Aeronautics... § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained overboard in flight or...

  15. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25.1455 Aeronautics... § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained overboard in flight or...

  16. A search for the Mpemba effect: When hot water freezes faster then cold water

    E-print Network

    Brownridge, James D

    2010-01-01

    An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water, then the hot water will usually freeze first, if all other conditions are equal and remain so during cooling. The probability that the hot water will freeze first if it has the higher spontaneous freezing temperature will be larger for a larger difference in spontaneous freezing temperature. Heating the water may lower, raise or not change the spontaneous freezing temperature. The keys to observing hot water freezing before cold water are supercooling the water and having a significant difference in the spontaneous freezing temperature of the two water specimens. We observed hot water freezing before cold water 28 times in 28 attempts und...

  17. Photomicrographic Investigation of Spontaneous Freezing Temperatures of Supercooled Water Droplets

    NASA Technical Reports Server (NTRS)

    Dorsch, R. G.; Hacker, P. T.

    1950-01-01

    A photomicrographic technique for investigating eupercooled. water droplets has been devised and. used. to determine the spontaneous freezing temperatures of eupercooled. water droplets of the size ordinarily found. in the atmosphere. The freezing temperatures of 4527 droplets ranging from 8.75 to 1000 microns in diameter supported on a platinum surface and 571 droplets supported on copper were obtained. The average spontaneous freezing temperature decreased with decrease in the size of the droplets. The effect of size on the spontaneous freezing temperature was particularly marked below 60 microns. Frequency-distribution curves of the spontaneous freezing temperatures observed for droplets of a given size were obtained. Although no droplet froze at a temperature above 20 0 F, all droplets melted at 32 F. Results obtained with a copper support did not differ essentially from those obtained with a platinum surface.

  18. Hadron Freeze-Out and Unruh Radiation

    E-print Network

    Paolo Castorina; Alfredo Iorio; Helmut Satz

    2014-09-10

    We consider hadron production in high energy collisions as an Unruh radiation phenomenon. This mechanism describes the production pattern of newly formed hadrons and is directly applicable at vanishing baryochemical potential, mu = 0. It had already been found to correctly yield the hadronisation temperature, T_h = sqrt(sigma / 2 pi) = 165 MeV in terms of the string tension sigma. Here we show that the Unruh mechanism also predicts hadronic freeze-out conditions, giving s/T_h^3 = 3 pi^2 / 4 = 7.4 in terms of the entropy density s and E/N = \\sqrt(2 pi sigma) = 1.09 for the average energy per hadron. These predictions provide a theoretical basis for previous phenomenological results and are also in accord with recent lattice studies.

  19. Freezing of Martian streams under climatic conditions

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The valley networks of Mars are widely believed to have formed at a time when climatic conditions on the planet were significantly different from those that currently prevail. This view arises from the following observations: (1) the valleys form integrated branching networks which suggests fluid drainage, and water is the most plausible fluid, (2) the present atmosphere contains only minute amounts of water, (3) the networks appear to be more akin to terrestrial valleys that are eroded by streams of modest discharges than features that form by catastrophic floods, and (4) small streams of water will rapidly freeze under present climatic conditions. Climatic conditions at the time of formation of the valleys are studied based on the assumption that they were cut by running water.

  20. STEFINS: a steel freezing integral simulation program

    SciTech Connect

    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.