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1

Behavior of water below the freezing point in PEFCs  

Microsoft Academic Search

This study investigates the phenomenon of water freezing below the freezing point in polymer electrolyte fuel cell (PEFCs). Water generated on the surface of the catalyst layer was observed simultaneously with visible and infrared images. Surprisingly, it was found that water generated below the freezing point is in the liquid state and that the temperature rises to 0°C at the

Yuji Ishikawa; T. Morita; K. Nakata; K. Yoshida; M. Shiozawa

2007-01-01

2

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

3

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

PubMed

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

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

2008-12-01

4

When hot water freezes before cold  

Microsoft Academic Search

I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is due to freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. The solutes are concentrated ahead of the freezing front by zone refining in water that has not been

J. I. Katz

2009-01-01

5

A method for on-line determination of residual water content and sublimation end-point during freeze-drying  

Microsoft Academic Search

Freeze-drying is a discontinuous process mainly used in the food and pharmaceutical industry to preserve the initial properties of raw products after dehydration. To date, the freeze-drying process has been monitored according to time-dependent empirical rules. Several authors have attempted to develop measuring systems for the on-line determination of the dehydration rate (freeze-drying kinetics) and the sublimation end-point. Of the

N. Genin; F. Rene; G. Corrieu

1996-01-01

6

Do stratospheric aerosol droplets freeze above the ice frost point?  

Microsoft Academic Search

Laboratory experiments are presented which show that liquid stratospheric aerosol droplets under polar winter conditions do not freeze for temperatures higher than the water ice saturation temperature (frost point). Calorimetric measurements of the freezing of supercooled H2SO4\\/HNO3\\/H2O bulk solutions with concentrations typical of the polar stratospheric aerosol exhibit very small freezing rates, which exclude the possibility of homogeneous freezing of

T. Koop; U. M. Biermann; W. Raber; B. P. Luo; P. J. Crutzen; Th. Peter

1995-01-01

7

Some Factors Affecting the Freezing Point of Milk1  

Microsoft Academic Search

The freezing point of milk has served for over 30 years as an official method (2) for detecting adulteration of milk with added water. Current investigations (4, 7, 10) have indicated that the present standard of - 0.550 ° C. is too low for the average freezing point of milk, and that average values frequently fall be- tween -- 0.535

I. Sato; C. L. Hankinson; I. A. Gould; T. V. Armstrong

1957-01-01

8

FREEZING POINT DEPRESSION OF VARIOUS ICE SLURRIES  

Microsoft Academic Search

Ideal solutions with equal molar concentration have an equal freezing point. The properties that determine heat and mass transfer processes encountered in a secondary cooling cycle are however determined by the mass fraction of solutes. Generally for aqueous solutions, the more freezing point depressant added, the less efficient heat and mass transfer properties. Therefore substances with low molecular weight are

J. W. Meewisse; C. A. Infante Ferreira

9

Magnetic freezing of confined water  

NASA Astrophysics Data System (ADS)

We report results from molecular dynamic simulations of the freezing transition of liquid water in the nanoscale hydrophobic confinement under the influence of a homogeneous external magnetic field of 10 T along the direction perpendicular to the parallel plates. A new phase of bilayer crystalline ice is obtained at an anomalously high freezing temperature of 340 K. The water-to-ice translation is found to be first order. The bilayer ice is built from alternating rows of hexagonal rings and rhombic rings parallel to the confining plates, with a large distortion of the hydrogen bonds. We also investigate the temperature shifts of the freezing transition due to the magnetic field. The freezing temperature, below which the freezing of confined water occurs, shifts to a higher value as the magnetic field enhances. Furthermore, the temperature of the freezing transition of confined water is proportional to the denary logarithm of the external magnetic field.

Zhang, Guangyu; Zhang, Weiwei; Dong, Huijuan

2010-10-01

10

Magnetic freezing of confined water.  

PubMed

We report results from molecular dynamic simulations of the freezing transition of liquid water in the nanoscale hydrophobic confinement under the influence of a homogeneous external magnetic field of 10 T along the direction perpendicular to the parallel plates. A new phase of bilayer crystalline ice is obtained at an anomalously high freezing temperature of 340 K. The water-to-ice translation is found to be first order. The bilayer ice is built from alternating rows of hexagonal rings and rhombic rings parallel to the confining plates, with a large distortion of the hydrogen bonds. We also investigate the temperature shifts of the freezing transition due to the magnetic field. The freezing temperature, below which the freezing of confined water occurs, shifts to a higher value as the magnetic field enhances. Furthermore, the temperature of the freezing transition of confined water is proportional to the denary logarithm of the external magnetic field. PMID:20942551

Zhang, Guangyu; Zhang, Weiwei; Dong, Huijuan

2010-10-01

11

Freezing behaviour of microencapsulated water.  

PubMed

The freezing behaviour of water in polyurea microcapsules was studied through DSC (differential scanning calorimetry) and ESR (electron spin resonance) measurements under a non-equilibrium condition to show that supercooling of water becomes more noticeable with decreasing droplet size of the liquid. Thermodynamics of small systems was found applicable to analyse the experimental findings, even though the process of water freezing in the microcapsules was not of an equilibrium nature. PMID:1328582

Yamane, H; Ohshima, H; Kondo, T

12

Freezing of supercooled water nanodroplets  

NASA Astrophysics Data System (ADS)

All three states of water play important roles in nature, from thermostating the atmosphere to providing reactive surfaces environments. The rates at which transitions between the phases occur, the degree to which pure liquid water can be supercooled, and the solid phases that form are all fundamentally interesting questions with strong atmospheric relevance. We have followed and characterized the nucleation, growth, and subsequent freezing of pure water droplets formed in a supersonic nozzle apparatus using both Small Angle X-ray Scattering (SAXS) and Fourier Transform Infrared Spectroscopy (FTIR). Because the droplets have radii r between 3 nm and 6 nm, and the cooling rates are on the order of 5E5 K/s, liquid water only begins to freeze below approximately 215 K. These temperatures are well below the homogeneous freezing limit for bulk water. The experiments show the expected decrease in freezing temperature with decreasing droplet size, or alternatively, with increasing droplet internal pressure.

Wyslouzil, Barbara

2013-03-01

13

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)

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.

Inaba, Hideo; Morita, Shin-Ichi

14

Hydrocarbon exclusion from ground water during freezing  

SciTech Connect

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.

Tumeo, M.A.; Davidson, B. (Univ. of Alaska, Fairbanks (United States))

1993-08-01

15

Improve online freeze and cloud point control  

SciTech Connect

To improve financial performance, petroleum refiners want tighter control on individual processing units. Consequently, modern refineries are moving product-quality analytical functions closer to process. Historically, processing units sent product samples to the laboratory and made adjustments based on analytical results. In some cases, the lag time between sample procurement an data return could be several hours. During this time, the unit could be producing off-spec product or operating in a nonoptimized mode while waiting on lab results. Under these conditions, the cost to the refinery could mean the difference between a profit or loss. Many quality requirements are associated with the refined products. Some are regulatory mandates, others are market or seasonally driven and some are driven by yield and process optimization objectives. For example, freeze and cloud point are process control parameters that can increase yields and improve financial performance. Opting to use online analyzers to monitor/control freeze and cloud point specifications has potential economical advantages. The paper discusses freeze and cloud point data, common problems with analyzers, and two case histories of monitoring petroleum refinery streams.

Davidson, F.; Tsang, C. [Phase Technology, Richmond, British Columbia (Canada)

1997-01-01

16

Measurement of Freezing Point Depression of Selected Food Solutions  

NASA Astrophysics Data System (ADS)

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.

Murata, Satoshi; Tanaka, Fumihiko; Matsuoka, Takahisa

17

Supercooled water behavior inside polymer electrolyte fuel cell cross-section below freezing temperature  

Microsoft Academic Search

This study investigated the phenomenon of water freezing below freezing point in polymer electrolyte fuel cells (PEFCs). To understand the details of water freezing phenomena inside a PEFC, a system capable of cross-sectional imaging inside the fuel cell with visible and infrared images was developed. Super-cooled water freezing phenomena were observed under different gas purge conditions. The present test confirmed

Y. Ishikawa; H. Hamada; M. Uehara; M. Shiozawa

2008-01-01

18

Standard Reference Material 1744: Aluminum Freezing-Point Standard.  

National Technical Information Service (NTIS)

The freezing point of aluminum (660.323 deg. C) is a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Realization of this freezing point is performed using a fixed-point cell containing high purity (greater than or equal to 99...

G. F. Strouse

1995-01-01

19

Effects of Salt Concentration Changes During Freezing on the Unfrozen Water Content of Porous Materials  

Microsoft Academic Search

By combining equations for salt concentration by water removal from porous bodies with those for freezing point depression in normal solutions, equations are developed for calculating freezing point depression shifts due to the gradual removal of water upon freezing in porous bodies. The same equations can be used for the calculation of shifts in the osmotic potential of the water

Amos Banin; Duwayne M. Anderson

1974-01-01

20

Freezing and Blocking of Water Pipes.  

National Technical Information Service (NTIS)

The topic addressed in this article is the freezing and blockage of water pipes that are full, with the water either flowing or still. It has long been assumed that when the water in a pipe freezes the ice begins to form on the inside surface of the pipe ...

K. L. Carey

1982-01-01

21

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

|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…

Tellinghuisen, Joel

2010-01-01

22

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

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…

Tellinghuisen, Joel

2010-01-01

23

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)

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.

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

2008-06-01

24

Salt Water Desalination by the Freezing Method.  

National Technical Information Service (NTIS)

Investigations of the most important units of the new method of salt water desalination by artificial freezing with the help of liquid hydrocarbons (propane-butane mixture) were conducted. Investigation of contact heat transfer processes indicates that th...

I. M. Rutgaizer S. Seitkurbanov V. I. Petrov

1969-01-01

25

Infrared spectroscopy of sulfuric acid/water aerosols: Freezing characteristics  

NASA Astrophysics Data System (ADS)

A low-temperature flow cell has been used in conjunction with a Fourier transform infrared (FT-IR) spectrometer to study sulfuric acid/water aerosols. The aerosols were generated with a wide range of composition (28 to 85 wt%), including those characteristic of stratospheric sulfate aerosols, and studied over the temperature range from 240 K to 160 K. The particles exhibited deep supercooling, by as much as 100 K below the freezing point in some cases. Freezing of water ice was observed in the more dilute (<40 wt% sulfuric acid) particles, in agreement with the predictions of Jensen et al. and recent observations by Bertram et al. In contrast with theoretical predictions, however, the entire particle often does not immediately freeze, at least on the timescale of the present experiments (seconds to minutes). Freezing of the entire particle is observed at lower temperatures, well below that characteristic of the polar stratosphere.

Clapp, M. L.; Niedziela, R. F.; Richwine, L. J.; Dransfield, T.; Miller, R. E.; Worsnop, D. R.

1997-04-01

26

A similar law may govern water freezing in minerals and living organisms  

Microsoft Academic Search

THERE is an interesting similarity between the freezing of water in minerals and in biological tissues. Mazur1,2 observed that many living organisms lose viability at threshold temperatures near -10 °C. After investigating this phenomenon from the point of view of possible mechanisms by which living cells suffer damage on freezing, he concluded that a key step in the freezing process

Amos Banin; Duwayne M. Anderson

1975-01-01

27

An inherently freeze protected solar water heater  

SciTech Connect

A solar water heater which uses a roof-contained solar absorber operating a two-phase thermosiphon with splash heat exchanger is described. Such a thermosiphon has operating characteristics which may be exploited to achieve simple and reliable freeze protection. An installation is described and the physical arrangements needed to obtain freeze protection are discussed. The results of a number of tests are presented.

Rush, C.K.

1983-06-01

28

Does Hot Water Freeze Faster Than Cold Water?  

NSDL National Science Digital Library

In this activity, conduct an experiment to find out if hot water can actually freeze faster than cold water. Investigate how impurities affect the freezing rate of varying temperatures of water. This activity guide includes a step-by-step instructional video.

Center, Saint L.

2013-01-17

29

NUMERICAL BENCHMARK BASED ON NATURAL CONVECTION OF FREEZING WATER  

Microsoft Academic Search

The proposed benchmark configuration concerns steady-state natural convection of water in the differentially heated cube-shaped cavity for temperatures close to the freezing point. Strongly non-linear buoyancy term allowed for thoughtful testing of several numerical approaches. After selecting the best performing one a new, very restrictive verification procedure is proposed. The verified numerical code is used to simulate the \\

Tomasz Michalek; Tomasz A. Kowalewski

30

Hot water can freeze faster than cold?!?  

Microsoft Academic Search

We review the Mpemba effect, where intially hot water freezes faster than initially cold water. While the effect appears impossible at first sight, it has been seen in numerous experiments, was reported on by Aristotle, Francis Bacon, and Descartes, and has been well-known as folklore around the world. It has a rich and fascinating history, which culminates in the dramatic

Monwhea Jeng

2005-01-01

31

Thermal properties of ration components as affected by moisture content and water activity during freezing.  

PubMed

Beef roast with vegetables is an example of a meal, ready-to-eat (MRE) ration entrée. It is a mixture of meat, potato, mushroom, and carrot with a gravy sauce. The thermal properties of each component were characterized in terms of freezing point, latent heat, freezable and unfreezable water contents, and enthalpy during freezing using differential scanning calorimetry. Freezing and thawing curves and the effect of freezing and thawing cycles on thermal properties were also evaluated. The freezing points of beef, potato, mushroom, and sauce were all in the range of -5.1 to -5.6 degrees C, but moisture content, water activity, latent heat, freezable and unfreezable water contents, and enthalpy varied among these components. Freezing temperature greatly affected the unfrozen water fraction. The unfreezable water content (unfrozen water fraction at -50 degrees C) of ration components was in the range of 8.2% to 9.7%. The freezing and thawing curves of vegetables with sauce differed from those of beef but took similar time to freeze or thaw. Freezing and thawing cycles did not greatly affect the thermal properties of each component. Freezing point and latent heat were reduced by decreasing moisture content and water activity of each component. Water activity was proportionally linear to freezing point at a(w) > 0.88, and moisture content was proportionally linear to freezable water content in all ration components. Water was not available for freezing when moisture content was reduced to 28.8% or less. This study indicates that moisture content and water activity are critical factors affecting thermal behavior of ration components during freezing. PMID:19021797

Li, J; Chinachoti, P; Wang, D; Hallberg, L M; Sun, X S

2008-11-01

32

The Freezing Point Depression Law in Physical Chemistry.  

ERIC Educational Resources Information Center

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)

Franzen, Hugo F.

1988-01-01

33

Interpreting freezing point depression of stearic acid and methyl stearate  

Microsoft Academic Search

Freezing point depressions of binary systems including either stearic acid (SA) or methyl stearate (MES) were evaluated based on differential scanning calorimetry melting scans. The second binary component included a solvent from the group acetic acid, acetone, 2-butanone, and hexane. Vapor pressure as a function of liquid composition and temperature was used to measure vapor\\/liquid equilibrium. Activity coefficients were calculated

M. J. Goff; G. J. Suppes; M. A. Dasari

2005-01-01

34

Freezing and melting water in lamellar structures.  

PubMed

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

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

1994-08-01

35

Evaporation of water from agitated freezing slurries at low pressure  

Microsoft Academic Search

In an absorptive vacuum freezing process, water evaporates from the freezing solution and condenses on a cold salt solution. Given sufficient condensing capacity, the evaporation rate will be controlled by the freezing solution vapor pressure. The size of the condensing equipment which matches a given evaporation system can be estimated using rate measurements made with low vapor pressure freezing solutions.

L. C. Dickey

1996-01-01

36

Thermosiphon solar water heater having freeze rupture protection  

SciTech Connect

A thermosiphon solar water heating system is described, having passive protection against freeze rupture during periods when insufficient solar energy exists for the system to generate heating and ambient air temperature conditions drop to the freezing point of water. It has a solar energy collector for generating heat, including cover for exposure to solar energy and ambient air. A water supply conduit is displaced from the cover, and a riser conduit is coupled to the water supply conduit and has an outlet. The riser conduit disposed between the cover and the water supply conduit so as to be in closer proximity to the cover than the water supply conduit. The riser conduit transfer heat to the water contained therein during periods when sufficient solar energy exists for the collector to generate heat, to cause water therein to become more buoyant than water in the supply conduit. The riser conduit cools the water contained therein more rapidly than the supply conduit cools the water contained in it during periods when insufficient solar energy exists for the collector to generate heat, and allowing the ambient temperature to cause water contained therein to be lowered in temperature to under 4/sup 0/C. and become more buoyant than water in the supply conduit the riser conduit discharges at its outlet water more buoyant than water in the supply conduit. A heated water storage tank is disposed adjacent and elevated above the solar collector. The outlet of the riser conduit is coupled to the water supply conduit.

Cole, S.W.

1986-07-15

37

When the melting and freezing points are not the same  

NASA Astrophysics Data System (ADS)

Small clusters consisting of from four or five to 100 or 200 atoms or molecules can coexist as solids and liquids over a finite temperature range and have distinctly different melting and freezing points. It is argued that the study of clusters offers a bridge between reductionists and those researching the properties of large aggregates of atoms or molecules, since the unlinking of the freezing and melting points is readily detectable in a small system, but not in bulk matter. The concepts of potential well, free energy, and a quantum-mechanical interpretation of the allowed energies of clusters are reviewed and presented as theoretical bases for different freezing and melting points in clusters. Both laboratory experiments and computer simulations provide evidence to support this theory. In particular, computer-simulated time histories of mean temperatures of argon-13 clusters of various constant energies are presented which show the coexistence of liquid and solid clusters. It is concluded that, because clusters can exist in many different stable forms, future synthesis of new kinds of materials possessing certain desired microelectric, mechanical, or catalytic properties may be possible.

Berry, R. Stephen

1990-08-01

38

Hydrocarbon exclusion from ground water during freezing  

Microsoft Academic Search

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

Mark A. Tumeo; Bret Davidson

1993-01-01

39

Molecular dynamics simulations of freezing of water and salt solutions  

Microsoft Academic Search

Results of extensive molecular dynamics simulations of freezing of neat water and aqueous sodium chloride solutions are reported. The process of water freezing in contact with an ice patch is analyzed at a molecular level and a robust simulation protocol within the employed force field is established. Upon addition of a small amount of NaCl brine rejection from the freezing

Luboš Vrbka; Pavel Jungwirth

2007-01-01

40

Freezing Points of Bulking Agents Used in Manufacture of Low-Calorie Frozen Desserts1  

Microsoft Academic Search

Freezing points of solutions of poly- dextrose, polydextrose partially neu- tralized with potassium hydroxide, sor- bitol, and microcrystalline cellulose at concentrations commonly used in frozen desserts were compared with those of similar concentrations of sucrose. Solu- tions of polydextrose and polydextrose partially neutralized with potassium hy- droxide exhibited higher freezing points. Freezing points of sorbitol solutions were lower and microcrystalline

Robert J. Baer; Kirk A. Baldwin

1984-01-01

41

Immersion freezing of birch pollen washing water  

NASA Astrophysics Data System (ADS)

In the present study, the immersion freezing behavior of birch pollen, i.e. its ice nucleating active (INA) macromolecules, was investigated at the Leipzig Aerosol Cloud Interaction Simulator (LACIS). For that, washing water of two different birch pollen samples with different regional origin (Northern birch and Southern birch) were used. The immersion freezing of droplets generated from the pollen washing water was already observed at temperatures higher than -20 °C, for both samples. Main differences between the Northern birch pollen and the Southern birch pollen were obvious in a temperature range, between -18 °C and -24 °C, where the ice fraction increased with decreasing temperature. There, the Northern birch pollen washing water featured two different slopes, with one being steeper and one being similar to the slope of the Southern birch pollen washing water. As we assume single INA macromolecules being the reason for the ice nucleation, we concluded that the Northern birch pollen are able to produce at least two different types of INA macromolecules. We were able to determine the heterogeneous nucleation rates for both INA macromolecule types and so could explain the ice nucleation behavior of both, the Southern and the Northern birch pollen washing water.

Augustin, S.; Hartmann, S.; Pummer, B.; Grothe, H.; Niedermeier, D.; Clauss, T.; Voigtländer, J.; Tomsche, L.; Wex, H.; Stratmann, F.

2012-12-01

42

Nucleation of Freezing in Supercooled Water by Cavitation  

Microsoft Academic Search

NUCLEATION of freezing in supercooled liquids by cavitation has been ascribed to a momentary large increase in the degree of supercooling, induced by the high transient pressures generated by a collapsing cavity. This is a plausible mechanism for substances which contract on freezing; for substances such as water, which expand on freezing, it seems less satisfactory1. Hickling2, however, has proposed

M. N. Plooster

1968-01-01

43

Chilled water coil freeze protection via internal drying  

SciTech Connect

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.

LaRocca, D.V. [Yale Univ. School of Medicine, New Haven, CT (United States). Building Services and Operations Dept.

1997-12-01

44

Standard Reference Materials: Tin Freezing-Point Standard: SRM 741a.  

National Technical Information Service (NTIS)

The freezing point of tin (231.928 degrees C) is a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Realization of this freezing point is performed using a fixed-point cell containing high-purity (> or = 99.9999% pure) tin. A ...

G. F. Strouse N. P. Moiseeva

1999-01-01

45

KEY COMPARISON: Final report on comparison COOMET.T-K3: Regional comparisons of the national standards of temperature in the range from the triple point of water to the freezing temperature of zinc  

NASA Astrophysics Data System (ADS)

The COOMET.T-K3 comparison is the regional comparison of the defining fixed points realization in the range from the triple point of water to the freezing point of zinc. Four national metrology institutes—VNIIM (pilot), SMU, BelGIM and NNC IM—took part in the COOMET regional comparisons. At the first stage the cells of fixed points of the national metrology institutes were used as transfer standards. They were compared with the VNIIM cells by means of standard platinum resistance thermometers using the VNIIM standard setups and equipment. At the second stage the equivalence of realization of the fixed points at the national institutes was estimated. A standard platinum resistance thermometer SPRT (25 ohm), manufactured at VNIIM, was used as a transfer standard. The degree of equivalence of the measurement standard of the national metrology institutes participating in the COOMET comparison is determined relative to the reference values of the CCT-K3 through the measurement results received in the linking national metrology institutes, VNIIM and SMU, which took part in both comparisons. The values 'ARV' of K3 were assumed as the reference values. The report presents the results of this comparison and gives detailed information about the method of estimation of the degree of equivalence of NMI standards and its uncertainty. 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, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Pokhodun, A. I.; Ivanova, A. G.

2008-01-01

46

Effects of electrode materials on freezing of supercooled water in electric freeze control  

Microsoft Academic Search

In order to clarify effects of electric charge on freezing of supercooled water, experiments were carried out with various kinds of electrodes in supercooled water. Water sample was kept in a test tube and cooled down at a constant cooling rate. When the water sample was maintained under a supercooling state, an electric charge was applied to the water sample

Tsutomu Hozumi; Akio Saito; Seiji Okawa; Kazuharu Watanabe

2003-01-01

47

Relationship of amino acid composition and molecular weight of antifreeze glycopeptides to non-colligative freezing point depression.  

PubMed

Many polar fishes synthesize a group of eight glycopeptides that exhibit a non-colligative lowering of the freezing point of water. These glycopeptides range in molecular weight between 2600 and 33 700. The largest glycopeptides [1-5] lower the freezing point more than the small ones on a weight basis and contain only two amino acids, alanine and threonine, with the disaccharide galactose-N-acetyl-galactosamine attached to threonine. The small glycopeptides, 6, 7, and 8, also lower the freezing point and contain proline, which periodically substitutes for alanine. Glycopeptides with similar antifreeze properties isolated from the saffron cod and the Atlantic tomcod contain an additional amino acid, arginine, which substitutes for threonine in glycopeptide 6. In this study we address the question of whether differences in amino acid composition or molecular weight between large and small glycopeptides are responsible for the reduced freezing point depressing capability of the low molecular weight glycopeptides. The results indicate that the degree of amino acid substitutions that occur in glycopeptides 6-8 do not have a significant effect on the unusual freezing point lowering and that the observed decrease in freezing point depression with smaller glycopeptides can be accounted for on the basis of molecular weight. PMID:7115772

Schrag, J D; O'Grady, S M; DeVries, A L

1982-08-01

48

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

Microsoft Academic Search

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.

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

2009-01-01

49

Mass Transfer and Thermodynamic Studies of Evaporative Freezing of Water.  

National Technical Information Service (NTIS)

Some of the key technical problems inherent in the design of equipment for the absorption, freezing, vapor-compression process for the production of pure water from salt water were investigated in laboratory studies. These included the comparison of vario...

R. L. Pigford

1983-01-01

50

Melting and freezing of water in cylindrical silica nanopores.  

PubMed

Freezing and melting of H(2)O and D(2)O in the cylindrical pores of well-characterized MCM-41 silica materials (pore diameters from 2.5 to 4.4 nm) was studied by differential scanning calorimetry (DSC) and (1)H NMR cryoporometry. Well-resolved DSC melting and freezing peaks were obtained for pore diameters down to 3.0 nm, but not in 2.5 nm pores. The pore size dependence of the melting point depression DeltaT(m) can be represented by the Gibbs-Thomson equation when the existence of a layer of nonfreezing water at the pore walls is taken into account. The DSC measurements also show that the hysteresis connected with the phase transition, and the melting enthalpy of water in the pores, both vanish near a pore diameter D* approximately equal to 2.8 nm. It is concluded that D* represents a lower limit for first-order melting/freezing in the pores. The NMR spin echo measurements show that a transition from low to high mobility of water molecules takes place in all MCM-41 materials, including the one with 2.5 nm pores, but the transition revealed by NMR occurs at a higher temperature than indicated by the DSC melting peaks. The disagreement between the NMR and DSC transition temperatures becomes more pronounced as the pore size decreases. This is attributed to the fact that with decreasing pore size an increasing fraction of the water molecules is situated in the first and second molecular layers next to the pore wall, and these molecules have slower dynamics than the molecules in the core of the pore. PMID:18825292

Jähnert, S; Vaca Chávez, F; Schaumann, G E; Schreiber, A; Schönhoff, M; Findenegg, G H

2008-08-13

51

Promising freeze protection alternatives in solar domestic hot water systems  

Microsoft Academic Search

Since the gains associated with solar thermal energy technologies are comparatively small in relation to the required capital investment, it is vital to maximize conversion efficiency. While providing the necessary function of freeze protection, the heat exchanger commonly included in solar domestic water heating systems represents a system inefficiency. This thesis explores two alternate methods of providing freeze protection without

1997-01-01

52

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...

53

Plant Moisture Stress: A Portable Freezing-Point Meter Compared with the Psychrometer1  

Microsoft Academic Search

A small portable instrument for measuring the freezing- point depression of plant tissue has been developed for field use. The instrument is easy to operate and can be constructed from materials costing less than $100. Moisture stress measurements made with the Freezing- point meter on a variety of plants were compared with vapor pressure psychrometer measurments. Variation be- tween duplicates

J. W. Cary; H. D. Fisher

1969-01-01

54

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

ERIC Educational Resources Information Center

|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…

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

2007-01-01

55

Fundamental Research on Freezing Process of Water Accompanied by Blockade  

NASA Astrophysics Data System (ADS)

Fundamental research was carried out on freezing process of water accompanied by blockade. Firstly, experiment on freezing using a vinyl vessel was performed. The vessel containing water was sealed and frozen in a low temperature bath. As internal presure increased, ice started to break suddenly and then continued to break frequently. Secondly, metal vessel was used and similar experiment was performed. Strain gauge was placed at eight points evenly distributed in circumferential direction on the vessel. It was found that the force acting on the vessel was so great that the vessel entered into a plastic region in very short time. It was also found that ice cracks influence the local strain value but the value is almost independent to its neighboring measurements. Approximate analysis was performed and compared with the experiment using metal vessel. The following two cases were assumed in the calculation. (1) Ice is so easy to break that the stress in the ice can be ignored. (2) Ice never break and always stay in elastic region. The experimental results laid somewhere between them but subsequently it approached the case (1).

Saito, Akio; Okawa, Seiji; Saito, Seiji

56

Effects of shapes of electrodes on freezing of supercooled water in electric freeze control  

Microsoft Academic Search

In order to clarify the effects of electric charge on freezing of supercooled water, experiments were carried out. Two kinds of shapes were used for tips of electrodes. One was the sharp end surface. The other was the flat end surface. Aluminum was selected as the material. Water sample was kept in a test tube and cooled down at a

Tsutomu Hozumi; Akio Saito; Seiji Okawa; Yoichiro Eshita

2005-01-01

57

Kinetics of Water Loss from Cells at Subzero Temperatures and the Likelihood of Intracellular Freezing  

PubMed Central

The survival of various cells subjected to low temperature exposure is higher when they are cooled slowly. This increase is consistent with the view that slow cooling decreases the probability of intracellular freezing by permitting water to leave the cell rapidly enough to keep the protoplasm at its freezing point. The present study derives a quantitative relation between the amount of water in a cell and temperature. The relation is a differential equation involving cooling rate, surface-volume ratio, membrane permeability to water, and the temperature coefficient of the permeability constant. Numerical solutions to this equation give calculated water contents which permit predictions as to the likelihood of intracellular ice formation. Both the calculated water contents and the predictions on internal freezing are consistent with the experimental observations of several investigators.

Mazur, Peter

1963-01-01

58

Using undercooling to measure the freezing points of aqueous solutions  

Microsoft Academic Search

In this paper, a new type of sensor for in-line measurements of antifreeze mass fraction in aqueous solutions is described. Its principles of operation are based on the exploitation of the temperature rise that accompanies the freezing of an undercooled solution. Measurements are performed on small volume samples, taken from a distribution loop. The device operates in batch and is

Vincent Ayel; Olivier Lottin; Elena Popa; Hassan Peerhossaini

2005-01-01

59

A kinetic isotope effect during ice formation by water freezing  

Microsoft Academic Search

A kinetic isotope effect is known to occur during ice formation from water vapor in a cloud; it is due to the difference in molecular diffusivities in air of HDO and H218O molecules. A similar effect is likely during water freezing since diffusion coefficients of HDO and H218O are also different in liquid water. Their values are however less different

R. Souchez; J. Jouzel; R. Lorrain; S. Sleewaegen; M. Stiévenard; V. Verbeke

2000-01-01

60

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable climatic conditions.

J. Boysen; J. Morotti

1993-01-01

61

Simplified apparatus and procedure for freezing-point determinations upon small volumes of fluid  

Microsoft Academic Search

For purposes of determining the freezing-point of small volumes of aqueous solutions the difficulties of undercooling are avoided by first freezing the sample and then determining the thawing-point. Apparatus and procedure specially designed for simplicity of construction and operation are described. The method works best with volumes of the order of 10-3 to 10-4 mm3 and its accuracy in terms

J A Ramsay; R H J Brown

1955-01-01

62

Measurement and data interpretation of the freezing point depression of milks  

Microsoft Academic Search

Freezing point depression of milks of various concentrations (i.e. 0–35 wt %) were measured by the thermistor cryoscope method. The method was initially validated using aqueous NaCl and sucrose solutions at high concentrations as their data are readily available in literature. The effect of fat content on freezing point depression of milk was found to be minimal. Effective molecular weights

Ping Chen; Xiao Dong Chen; Kevin W. Free

1996-01-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

64

Glass Transition and Water Activity of Freeze-Dried Shark  

Microsoft Academic Search

Glass transition temperatures and water activity as a function of moisture content were determined for freeze-dried shark to further compare the two distinct criteria of food stability. The adsorption experiments were carried out at controlled water activity, at 21, 40, and 50°C using an isopiestic method and they were modeled using BET and GAB equations. Glass transition temperatures were measured

Shyam S. Sablani; Stefan Kasapis

2006-01-01

65

A Model-Guided Determination of ? dis G 2 ? for Slightly Soluble Gases in Water Using Solubility Data: From the Solvent’s Freezing Point to Its Critical Point  

Microsoft Academic Search

There is continuing interest in the description of the solubility of nonpolar gases in water over a wide range of temperatures.\\u000a On one hand, the solubility data are used in many fields of science and technology; and on the other hand, simulation and\\u000a theoretical calculations require experimental data to test their results and predictions. For these reasons it is important

Jorge Alvarez; Roberto Fernández-Prini

2008-01-01

66

Units of freezing of deep supercooled water in woody xylem.  

PubMed

The low temperature exotherms (LTE) of 1-year-old twigs of Haralson apple (Malus pumila Mill.), shagbark hickory (Carya ovata [Mill.] K. Koch), green ash (Fraxinus pennsylvanica Marsh), honey locust (Gleditsia triacanthos L.), American chestnut (Castanea dentata [Marsh] Borkh.), and red oak (Quercus rubra L.) were determined by differential thermal analysis (DTA). In one type of experiment freezing during a DTA experiment was halted for up to 2.5 hours after part of the supercooled water had frozen at temperatures between -25 and -42 C. Upon resumption of cooling the freezing started within 2 C of the stopping temperature. In a second type of experiment living and dead cells were microscopically observed in the same ray after partial freezing in the DTA apparatus. In another experiment, the LTE persisted even after tangential and radial sectioning of the twig to 0.13 millimeters. In a final experiment the LTE of a single multiseriate ray of red oak had the same shape as the LTE of wood with many uniseriate rays.These experiments confirm that the deep supercooled water in woody xylem or pith freezes in numerous independent events over a span of as much as 20 C. The units which freeze in an event are single cells or small groups of cells. Ice grows very slowly if at all from these units, and water moves very slowly from unfrozen cells to frozen ones. Deep supercooling of ray parenchyma does not require an intact ray. PMID:16661390

Hong, S G; Sucoff, E

1980-07-01

67

Preventing livestock water from freezing. Forest Service project record  

SciTech Connect

Available equipment for, and approaches to, preventing livestock water from freezing were surveyed in terms of water circulation, mass insulation, heat pipes, and solar energy. Use of insulated covers and applying insulation to the sides of stock tanks should be considered for ice-free stock water tanks. The propane bubbler seems the most simple and cost-effective freeze-prevention technique in climates that are not extreme. Photovoltaic-powered, water-circulation pumps appear to be practical and, because of their low cost, should be further investigated. Mass-insulated tanks are probably one of the simplest and most certain of the approaches presented for preventing freezing in livestock watering tanks. Heat pipes are an alternative to the propane bubbler that do not require a nonrenewable energy source. Photovoltaic cells to power an electric coil heater for freeze prevention in livestock stock tanks is impractical because of the high cost of the photovoltaic cells. Solar-heated (greenhouse effect), water-immersed, insulated tanks within a stock tank are considered excellent.

McKenzie, D.W.; Kashuba, T.J.; Waddington, D.; Leboeuf, C.M.; May, E.K.

1983-11-01

68

The Temperature Dependence of Water's Latent Heat of Freezing  

NASA Astrophysics Data System (ADS)

Freezing of water in Earth's atmosphere affects cloud dynamics through the release of the latent heat. The latent heat released is a function of how deeply the cloud water is supercooled before freezing begins - the deeper the supercooling, the less heat is released to the atmosphere. We present new measurements of the temperature dependent latent heat of freezing of water, measured using a Perkin Elmer DSC 7 and a Mettler Toledo Polymer DSC. Both instruments have been calibrated against melting transitions of water, dodecane, undecane,and tetradecane, and both agree within the error of the measurements with values in the literature. However, the two measurements show dramatic differences for the latent heat of freezing of water, which we attribute to the different methods used to extract a heat flux. At higher temperatures our measurements with the Perkin Elmer, which is a power compensation type calorimeter, are comparable to those of Bertolini et al. (1985). At lower temperatures, our measurements diverge from those of Bertolini et al. (1985), which we again attribute to the different principle of operation of the calorimeters. We conclude that temperature gradients within the freezing water play a critical role in the quantity of heat eventually exchanged with the surroundings. Finally, we reconcile the measurements with Kirchhoff's relation, which can be written (??H/?T)p = ?cp where ?H is the enthalpy difference between product and reactant (supercooled water and ice in this case) and ?cp is the difference in their heat capacities. [Bertolini, D., M. Cassettari, and G. Salvetti, Anomalies in the latent-heat of solidification of supercooled water. Chem. Phys. Lett., 119, 553-555, 1985.

Szedlak, A.; Blanchard, A. V.; Kostinski, A. B.; Cantrell, W. H.

2009-12-01

69

Report to the CCT on COOMET comparison COOMET.T-K3.1 (previously COOMET.T-S1): Key regional comparison of the national standards of temperature in the range from the triple point of water to the freezing point of zinc  

NASA Astrophysics Data System (ADS)

In the framework of the CIPM MRA, a first COOMET comparison "Comparison of the ITS-90 realizations in the range from 0.01 °C to 429.7485 °C (from the triple point of water to the freezing point of zinc)", registered in the KCDB under the identifier "COOMET.T-K3", was carried out in 2005-2007. Four national metrology institutes took part in this comparison: VNIIM (Russian Federation), SMU (Slovakia), BelGIM (Republic of Belarus) and NSC IM (Ukraine), and two of them (VNIIM and SMU) ensured the linkage with key comparisons CCT-K3 and CCT-K4, in order to disseminate the metrological equivalence to the measurement standards of NSC IM and BelGIM. NSC IM, however, had to withdraw its results, and at the meeting of Technical Committee T-10 of COOMET it was decided to carry out a supplementary bilateral comparison between VNIIM and the NSC IM for realization of the ITS-90 in the same range of temperature. This was registered in the KCDB under the identifier COOMET.T-S1 and measurements were performed in 2008-2009. From the results presented in this report, it is possible to draw the conclusion that the COOMET supplementary comparison COOMET.T-S1 demonstrates the CMC uncertainties claimed by the NSC IM for the melting point of gallium 0.236 mK (k = 2), and the freezing points of indium 1.040 mK (k = 2), tin 0.858 mK (k = 2) and zinc 0.944 mK (k = 2). In September 2012 the Working Group on key Comparisons (WG 7) of the CCT upgraded this comparison to a COOMET key comparison of the 'CCT-K3' type. It is now identified as COOMET.T-K3.1. In April 2013 this report was superseded by item 03006 in the Technical Supplement of 2013. 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, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Pokhodun, A. I.

2010-01-01

70

Demulsification of oil-in-water emulsion under freezing conditions: Effect of crystal structure modifier  

Microsoft Academic Search

The demulsification of oil-in-water (O\\/W) emulsions under freezing conditions is connected to fat crystallization in the oil\\u000a droplet. Therefore, demulsification can be prevented by the use of oil with a low melting point, and also by lowering the\\u000a O\\/W ratio. However, an oil with a low melting point, such as sunflower, is rather expensive, and the O\\/W ratio has a

Takuya Harada; Kazuhisa Yokomizo

2000-01-01

71

Thermal analysis study on water freezing and supercooling  

Microsoft Academic Search

Water freezing and supercooling were experimentally studied by methods of thermal analysis in a water droplet of 5 mm in diameter\\u000a depending on various temperatures and times of overheating and cooling rates. Degree of water supercooling was influenced\\u000a by previous thermal treatment but only to a certain extent. It increased slightly with overheating temperature and time and\\u000a decreased with cooling

K. Nitsch

2009-01-01

72

AC Corona in Foul Weather I-Above Freezing Point  

Microsoft Academic Search

After a brief survey of water appearance in the close-to-ground layer of atmosphere, behavior of water drops in the electric field is analyzed and the mechanism of streamer formations shown. Water influence, causing corona increase, has two components: (1) discharges between conductor and passing drops and (2) streamers produced by water presence on the conductor. Results of some attempts to

L. Boulet; B. J. Jakubczyk

1964-01-01

73

Optimization of SPRT measurements of freezing in a zinc fixed-point cell  

NASA Astrophysics Data System (ADS)

A numerical model of solute and heat transport in extremely pure materials is described. Its purpose is to characterize the effect of impurities on the freezing curves of metals containing impurities at the level of less than 1 part per million. It is used to simulate experiments performed using a commercially available zinc fixed-point cell for SPRT calibrations. The aim is to determine the effect of different vertical temperature gradients on the freezing curve and to find out whether a range of conditions could be determined where there was a good fit between theory and experiment. For this fixed-point cell, agreement between the model and experiment improves as the distribution coefficient k ? 0. It is found that the model only agrees with the measured freezing curves over the entire freeze for a narrow range of furnace settings where the temperature profile is most uniform. We suggest that this is because if the furnace settings are not optimized, the solid does not grow uniformly, and freezing may continue in regions remote from the SPRT after the material in the vicinity of the SPRT has finished freezing, so distorting the freezing curve. This effect is not present in the model and so the method presented here enables optimization of the furnace to ensure the SPRT is surrounded by a liquid-solid interface over the entire freezing range. We find that the optimum thermal environment is extremely sensitive to the furnace settings; the optimum thermal environment is found when the temperature is slightly cooler at the top of the cell, as measured in the re-entrant well of the cell. We note that optimizing the freezing process is a necessary step towards using a thermal analysis to correct for the effects of impurities in the sample.

Pearce, J. V.; Veltcheva, R. I.; Lowe, D. H.; Malik, Z.; Hunt, J. D.

2012-06-01

74

Spontaneous freezing of supercooled water under isochoric and adiabatic conditions.  

PubMed

The return of a supercooled liquid to equilibrium usually begins with a fast heating up of the sample which ends when the system reaches the equilibrium freezing temperature. At this stage, the system is still a microsegregated mixture of solid and liquid. Only later is solidification completed through the exchange of energy with the surroundings. Using the IAPWS-95 formulation, we investigate the adiabatic freezing of supercooled water in a closed and rigid vessel, i.e., under thermally and mechanically isolated conditions, which captures the initial stage of the decay of metastable water to equilibrium. To improve realism further, we also account for a fixed amount of foreign gas in the vessel. Under the simplifying assumption that the system is at equilibrium immediately after the nominal freezing temperature has been attained, we determine-as a function of undercooling and gas mole number-the final temperature and pressure of the system, the fraction of ice at equilibrium, and the entropy increase. Assuming a nonzero energy cost for the ice-water interface, we also show that, unless sufficiently undercooled, perfectly isolated pure-water droplets cannot start freezing in the bulk. PMID:23799647

Prestipino, Santi; Giaquinta, Paolo V

2013-06-25

75

Organic Absorbents for Triple Point Absorption Freeze Crystallization Processes.  

National Technical Information Service (NTIS)

Calculations were made to predict the absorption characteristics of various classes of organic molecules. Pertinent absorption refrigeration characteristics were found to be water-absorbent composition, miscibility of the absorbent and absorbed water, and...

J. A. Heist

1982-01-01

76

Freezing points of H2SO4 aqueous solutions and formation of stratospheric ice clouds  

Microsoft Academic Search

The freezing temperature of H2SO4 aqueous solutions as a function of concentration was experimentally measured in an investigation of the ice nucleation of natural H2SO4 mixed aerosols. Based on these measurements, it is suggested that the formation of ice crystals in cirrus and polar stratospheric clouds is the result of the condensation of water vapor and subsequent freezing of natural

Takeshi Ohtake

1993-01-01

77

Phenomena of Pipe Fracture by Freezing Water in Air Conditioner  

NASA Astrophysics Data System (ADS)

When water is frozen at some parts inside a pipe, the pressure of water blockaded by growing ice increases unusually and the pipe would be deformed to fracture under a certain circumstance. The behavior of pipe fracture cannot be explained by the volume expansion during phase change that the water is frozen and the ice is growing to the radius direction of pipe. In this study, we have investigated experimentally the behavior of pipe fracture for a plate fin coil in air conditioner about the freezing location, the growing direction of ice, and the change of water pressure and the deformation of pipe in the ice growing process. Moreover, we examined the behavior of water pressure in the ice growing process by numerical analysis. The pressure of water blockaded by growing ice increased to 20 MPa or more. This high water pressure deforms the pipe; the thickness and strength of pipe remarkably decrease at a time of freezing. Therefore, after the deformations of the pipe are repeated by freezing, the pipe could be fractured easily under the normal operating condition.

Chiba, Ryoichi; Shoji, Yoshiaki; Tanino, Masayuki; Izumi, Masaaki

78

Urine Processing for Water Recovery via Freeze Concentration  

Microsoft Academic Search

Resource recovery, including that of urine water extraction, is one of the most crucial aspects of long-term life support in interplanetary space travel. This paper will consequently examine an innovative approach to processing raw, undiluted urine based on low-temperature freezing. This strategy is uniquely different from NASA's current emphasis on either 'integrated' (co-treatment of mixed urine, grey, and condensate waters)

Jeffrey M. Schmidt; James E. Alleman

2005-01-01

79

How does water freeze inside carbon nanotubes?  

Microsoft Academic Search

Phase behavior of quasi-one-dimensional water confined inside a carbon nanotube is studied in the thermodynamic space of temperature, pressure, and diameter of the cylindrical container. Four kinds of solid-like ordered structures—ice nanotubes—form spontaneously from liquid-like disordered phases at low temperatures. In the model system that comprises of TIP4P water molecules interacting with each other via short-range Lennard–Jones and long-range Coulomb

Kenichiro Koga; G. T. Gao; Hideki Tanaka; X. C. Zeng

2002-01-01

80

Measurement of the in freezing-point temperature: Effect of the liquid-solid interface structure  

NASA Astrophysics Data System (ADS)

The results of the experimental study of the inner interface formation process under different conditions of its initiation for the indium freezing point showed that, depending on the initiation intensity, both the planar structure of the interface on the thermometer well and a noticeable intergrowth of dendrites could be obtained. However, under some specific initiation conditions dendrites disappeared partly or completely in the process of crystallization. The value of the indium freezing point temperature was measured under realization conditions corresponding to different inner interface structure.

Ivanova, A. G.; Abasov, M. Yu.; Gerasimov, S. F.; Pokhodun, A. I.

2013-09-01

81

Osmotic coefficient of aqueous solutions of cyclohexylsulfamic Acid at the freezing point of solutions.  

PubMed

The osmotic coefficient of aqueous solutions of cyclohexylsulfamic acid was determined by freezing point measurements up to the molality 0.65 mol kg-1. The osmotic coefficients were fitted to the Pitzer equation, and ion interaction parameters ?1, ?(0) and ?(1) were evaluated. The mean ion activity coefficient of the solute was calculated, and the non-ideal behaviour of the system investigated was characterized by calculation of the excess Gibbs energy of solution, as well as the respective partial molar functions of solute and solvent. The partial molar excess Gibbs energy of the solute is negative, like the excess Gibbs energy of its solution, while the partial molar excess Gibbs energy of the solvent is positive and increases with increasing concentration of the solute. The solvation ability of water was calculated from the difference between the Gibbs energy of solution of water in solution and that of pure water, and found to be positive and small for the solute investigated, throughout the concentration range studied. PMID:24061887

Bešter-Roga?, Marija; Klofutar, Cveto; Rudan-Tasi?, Darja

2010-12-01

82

Thermodynamic temperature measurements of silver freezing point and HTFPs  

NASA Astrophysics Data System (ADS)

The hybrid method, by introducing a lens to the irradiance method, was adopted to measure the thermodynamic temperature at NIM. An absolute radiation thermometer was established with two alternative filter radiometers (633nm and 900nm). The parameters of the absolute radiation thermometer were calibrated. The thermodynamic temperatures of the silver fixed point and Co-C, Pt-C, Re-C were determined. The uncertainties were 0.24K to 0.94K for FR633 and 0.34K to 1.6K for FR900 from the silver point to Re-C. The results were compared with the ITS-90 values and show a good agreement: 0.18K at Co-C, -0.11K at Pt-C and -0.24K at Re-C, which are under the estimated uncertainties.

Yuan, Z.; Lu, X.; Hao, X.; Dong, W.; Wang, T.; Lin, Y.; Wang, J.; Duan, Y.

2013-09-01

83

Freezing, fragmentation, and charge separation in sonic sprayed water droplets  

NASA Astrophysics Data System (ADS)

Water droplets are generated by sonic spray, transferred into vacuum through a capillary interface, and then passed through two image charge detectors separated by a drift region. The image charge detectors measure the charge and velocity of each droplet. For around 1% of the droplets, the charge changes significantly between the detectors. In some cases it increases, in others it decreases, and for some droplets the charge changes polarity. We attribute the charge changing behavior to fragmentation caused by freezing. Simulations indicate that the time required for a droplet to cool and freeze in vacuum depends on its size, and that droplets with radii of 1-2 [mu]m have the right size to freeze between the two detectors. These sizes correspond to the smaller end of the distribution present in the experiment. When the charge on a droplet increases or changes polarity, fragmentation must be accompanied by charge separation where fragments carry away opposite charges. In some cases, two fission fragments were observed in the second charge detector. We show examples where the droplet breaks apart to give fragments of the same charge and opposite charges. The fragmentation and charge changing behavior found here is consistent with what has been found in the freezing of larger suspended and supported droplets.

Zilch, Lloyd W.; Maze, Joshua T.; Smith, John W.; Jarrold, Martin F.

2009-06-01

84

Freeze–thaw stability of water-in-oil emulsions  

Microsoft Academic Search

Factors influencing water-in-oil emulsion stability during freeze\\/thaw-cycling, namely interfacial crystallization vs. network crystallization and the sequence of crystallization events (i.e., dispersed vs. continuous phase or vice versa), are assessed. We show that destabilization is most apparent with a liquid-state emulsifier and a continuous oil phase that solidifies prior to the dispersed phase. Emulsions stable to F\\/T-cycling are obtained when the

S. Ghosh; D. Rousseau

2009-01-01

85

FREEZING POINT DETERMINATIONS OF THE URANIUM HEXAFLUORIDE-HYDROGEN FLUORIDE SYSTEM  

Microsoft Academic Search

A more efficient and time-conserving method for the production analysis ; of small amounts of HF in UFâ is presented. The apparatus includes ; automatic controllingrecording equipment and thermistors. The amount of HF as an ; impurity is determined by measuring the depression in the UFâ freezing ; point. The use of calibration curves is necessary to correct for the

H. L. Bullard; A. S. Ostroski; W. S. Stringham

1957-01-01

86

Freezing point elevation in nanospace detected directly by atomic force microscopy  

Microsoft Academic Search

Following the earlier molecular simulation work by the authors, in which freezing point elevation in nanospace caused by the attractive potential energy from pore wall had been predicted, an experimental trial for finding the elevation phenomena was conducted, employing the so-called colloidal-probe Atomic Force Microscopy. A carbon microparticle was attached to the top of the cantilever tip, and its interaction

M. Miyahara; M. Sakamoto; H. Kanda; K. Higashitani

2002-01-01

87

Crosslinking on ageing of elastomers II. Comparison of solvent freezing point depression and conventional crosslinking evaluation  

Microsoft Academic Search

The crosslinking of ethylene propylene diene monomer (EPDM) resulting from photooxidation was followed by DSC. The thermograms of solvent confined in the gel at equilibrium were recorded. A decrease of the freezing point of the solvent with the irradiation time was observed, together with a decrease of the heat of solidification of the solvent and a widening of the crystallization

Mohamed Baba; Jean-Luc Gardette; Jacques Lacoste

1999-01-01

88

Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods  

Microsoft Academic Search

As a response to recent expression of concern about possible unreliability of vapor pressure deficit measurements (K. Kiyosawa, Biophys. Chem. 104 (2003) 171–188), the results of published studies on the temperature dependence of the osmotic pressure of aqueous polyethylene glycol solutions are shown to account for the observed discrepancies between osmolality estimates obtained by freezing point depression and vapor pressure

Donald J. Winzor

2004-01-01

89

Performance Characteristics of a New Single-Sample Freezing Point Depression Osmometer  

Microsoft Academic Search

The Advanced® Model 3320 is an automated, single-sample freezing point depression (FPD) micro- osmometer that determines the total solute concentration (osmolality) of biological fluids, such as serum or urine. Osmolality measurements are commonly used by clinicians to assist in diagnosing and monitoring certain fluid and electrolyte imbalances in patients (i.e., hyponatremia, polyuria). FPD osmometers have been used in clinical chemistry

E. Garry; M. Pest; N. Zamp

2007-01-01

90

Geographic constraints on passive solar domestic hot water systems due to pipe freezing  

Microsoft Academic Search

The supply and return piping of passive solar domestic hot water systems (SDHWS) is typically exposed to ambient weather conditions, and damaging pipe freeze is a major concern. This paper presents a pipe-freeze model that accounts for hot water draws and uses 30 years of actual weather data. The simulation results are cast in terms of pipe-freeze probabilities. Using contour

Jim Salasovich; Jay Burch; Greg Barker

2002-01-01

91

Isotope effects in aqueous systems. VI. partial molal free energies in NaCl?H 2 O?D 2 O by freezing-point measurements. The heat of fusion of D 2 O  

Microsoft Academic Search

The freezing-point depressions of solutions of NaCl in normal and heavy water have been measured between 0.01 and 2m. Extrapolation of the isotope effect data to infinite dilution yields a new value for the heat of fusion of D2O at its melting point (?1507±3 cal-mole?1). The freezing-point data were employed to obtain osmotic coefficients at the feezing points of the

Quentin D. Craft; W. Alexander Hook

1975-01-01

92

Characterization of polymer networks by measurements of the freezing point depression  

Microsoft Academic Search

Based on the phenomenon of freezing point depression of a solvent by?T, experimental evidence is presented to show that the distance between the junction points can be calculated from?T. Direct measurements of the temperature-time-curve of the cooling network and the Differential Scanning Calorimetry offer the determination of?T. Except the mean distances ¯dc in dependence on cross-linking density, swelling degree, and

K. F. Arndt; P. Zander

1990-01-01

93

Saturation, Phase Composition and Freezing Point Depression in a Rigid Soil Model.  

National Technical Information Service (NTIS)

Calorimetry was used to explore the effects of saturation and temperature upon the phase composition of the water at below freezing temperatures in a porcelain block with fine pore spaces. The effect of pore size upon phase composition was held constant b...

G. R. Lange H. L. McKim

1967-01-01

94

Planar solidification of a finite slab: effects of the pressure dependence of the freezing point  

Microsoft Academic Search

Planar solidification in a slab of finite thickness is numerically simulated. The solid density is assumed to be lower than the liquid density and the phase change material expands while freezing (e.g. water). The effects of an opposing elastic force, due to the interaction with the container, are analysed. The increasing pressure determines a continuous lowering of the melting temperature;

M. Conti

1995-01-01

95

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

Microsoft Academic Search

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

K. Hayashi; K. Kasza

2000-01-01

96

A comment on the Equation of State and the freezing point equation with respect to subglacial lake modelling  

NASA Astrophysics Data System (ADS)

The empirical Equation of State (EOS) allows the calculation of the density of water in dependence of salinity, temperature, and pressure. Water density is an important quantity to determine the internal structure and flow regime of ocean and lakes. Hence, its exact representation in numerical models is of utmost importance for the specific simulation results. The three parameters namely salinity, temperature, and pressure have a complex interdependency on the EOS. Whether warmer water parcels sink or rise, therefore depends on the surrounding salinity and pressure. The empirical Equation of Freezing Point (EOFP) allows to calculate the pressure- and salinity-dependent freezing point of water. Both equations are necessary to model the basal mass balance below Antarctic ice shelves or at the ice-water interface of subglacial lakes. This article aims three tasks: first we comment on the most common formulations of the EOS and the EOFP applied in numerical ocean and lake models during the past decades. Then we describe the impact of the recent and self-consistent Gibbs thermodynamic potential formulation of the EOS and the EOFP on subglacial lake modelling. Finally, we show that the circulation regime of subglacial lakes covered by at least 3000 m of ice, in principle, is independent of the particular formulation, in contrast to lakes covered by a shallower ice sheet, like e.g., Subglacial Lake Ellsworth. However, as modelled values like the freezing and melting patterns or the distribution of accreted ice at the ice-lake interface are sensitive to different EOS and EOFP, we present updated values for Subglacial Lake Vostok and Subglacial Lake Concordia.

Thoma, Malte; Grosfeld, Klaus; Smith, Andrew M.; Mayer, Christoph

2010-05-01

97

Promising freeze protection alternatives in solar domestic hot water systems  

SciTech Connect

Since the gains associated with solar thermal energy technologies are comparatively small in relation to the required capital investment, it is vital to maximize conversion efficiency. While providing the necessary function of freeze protection, the heat exchanger commonly included in solar domestic water heating systems represents a system inefficiency. This thesis explores two alternate methods of providing freeze protection without resorting to a heat exchanger. Commonly, collectors are made of rigid copper tubes separated by copper or aluminum fins. Cracking damage can occur when water is allowed to freeze and expand inside the non compliant tubes. The possibility of making collectors out of an elastic material was investigated and shown to be effective. Since unlike copper, elastomers typically have low thermal conductivities, the standard collector performance prediction equations do not apply. Modified thermal performance prediction equations were developed which can be used for both low and high thermal conductivity materials to provide accurate predictions within a limited range of plate geometries. An elastomeric collector plate was then designed and shown to have comparable performance to a copper plate collector whose aperture area is approximately 33% smaller. Another options for providing freeze protection to an SDHW system is to turn it off during the winter. Choosing a three-season operating period means two things. First, the system will have different optimums such as slope and collector area. Second, the wintertime solar energy incident on the collector is unavailable for meeting a heating load. However, the system`s heat exchanger becomes unnecessary and removing it increases the amount of energy that arrives at the storage tank during those periods in which the system is operating.

Bradley, D.E.

1997-12-31

98

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

SciTech Connect

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.

Bodnar, R.J. (Virginia Polytechnic Inst. and State Univ., Blacksburg (United States))

1993-02-01

99

Characterisation of the nanoporous structure of collagen-glycosaminoglycan hydrogels by freezing-out of bulk and bound water.  

PubMed

The nanoporous structure of collagen-glycosaminoglycan (CG) hydrogels was studied using 1H NMR spectroscopy and thermally stimulated depolarisation (TSD) current with layer-by-layer freezing-out of bulk and interfacial water. The depression of the freezing point of water is related to the size of the nanopore, to which it is confined. Changes in the Gibbs free energy of the unfrozen interfacial water are related to the amount of bound water in the hydrogel matrix and to the re-arrangement of the 3D network structure of the biopolymer. Analysis of the thermodynamic properties of bulk and interfacial water using the layer-by-layer freezing-out technique combined with NMR and TSDC provides valuable information about the structural features of CG hydrogels that can be used for characterisation of different types of hydrogels and soft tissue scaffolds, artificial skin substitutes and other biomaterials. PMID:16519934

Mikhalovska, Lyuba I; Gun'ko, Vlad M; Turov, Vlad V; Zarko, Vlad I; James, Stuart L; Vadgama, Pankaj; Tomlins, Paul E; Mikhalovsky, Sergey Victorovich

2006-03-07

100

Freeze-thaw stability of water-in-oil emulsions.  

PubMed

Factors influencing water-in-oil emulsion stability during freeze/thaw-cycling, namely interfacial crystallization vs. network crystallization and the sequence of crystallization events (i.e., dispersed vs. continuous phase or vice versa), are assessed. We show that destabilization is most apparent with a liquid-state emulsifier and a continuous oil phase that solidifies prior to the dispersed phase. Emulsions stable to F/T-cycling are obtained when the emulsifier crystallizes at the oil-water interface or in emulsions where the continuous phase crystallizes after the dispersed aqueous phase. The materials used are two food-grade oil-soluble emulsifiers - polyglycerol polyricinoleate (PGPR) and glycerol monostearin (GMS) and two continuous oil phases with differing crystallization temperatures - canola oil and coconut oil. Emulsion stability is assessed with pulsed field gradient NMR droplet size analysis, sedimentation, microscopy and differential scanning calorimetry. This study demonstrates the sequence of crystallization events and the physical state of the surfactant at the oil-water interface strongly impact the freeze-thaw stability of water-in-oil emulsions. PMID:19683718

Ghosh, S; Rousseau, D

2009-07-25

101

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

NASA Astrophysics Data System (ADS)

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.

Zhang, Jin Tao; Wang, Y. N.

2008-06-01

102

FREEZING POINT DEPRESSIONS IN SODIUM FLUORIDE. II. EFFECT OF TETRAVALENT FLUORIDES  

Microsoft Academic Search

The freezing point depressions in NaF caused by ZrFâ, HfFâ, ; ThFâ, and UFâ were measured and the excess partial molal free ; energies of solution of NaF calculated therefrom. All the deviations from ideal ; solution behavior were negative and greater than these for alkaline earth ; fluoride solutes. It was found that the deviations increase with the tetravalent

S. Cantor; T. S. Carlton

1962-01-01

103

Comparison of human tear film osmolarity measured by electrical impedance and freezing point depression techniques  

Microsoft Academic Search

Tear hyperosmolarity is diagnostic of dry eye disease (DED), yet difficulty in measurement has limited its utility; development of new instruments could facilitate its clinical application. This study compares the new OcuSense TearLab osmometer (OcuSense, Inc, San Diego, CA), based on electrical impedance “lab-on-a-chip” nanoliter technology, with the freezing point depression Clifton Osmometer (Clifton Technical Physics, Hartford, NY).

Alan Tomlinson; Louise C. McCann; Edward I Pearce

2010-01-01

104

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

PubMed

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

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

2009-02-14

105

Water Freezes Differently on Positively and Negatively Charged Surfaces of Pyroelectric Materials  

Microsoft Academic Search

Although ice melts and water freezes under equilibrium conditions at 0°C, water can be supercooled under homogeneous conditions in a clean environment down to -40°C without freezing. The influence of the electric field on the freezing temperature of supercooled water (electrofreezing) is of topical importance in the living and inanimate worlds. We report that positively charged surfaces of pyroelectric LiTaO3

David Ehre; Etay Lavert; Meir Lahav; Igor Lubomirsky

2010-01-01

106

Effect of maximum density of water on freezing of a water-saturated horizontal porous layer  

Microsoft Academic Search

This experiment simulates the freezing of water in a layer of earth by the use of a porous bead layer. The layer is cooled from above. The beads are 1, 5, and 11-mm-dia glass and 11-mm-dia steel. When the predominant heat transfer mode in an unfrozen layer is conduction, the freezing rate is not affected by the bead diameter. However,

M. Sugawara; H. Inaba; N. Seki

1988-01-01

107

Influence of surface water activity on freezing\\/thawing times and weight loss prediction  

Microsoft Academic Search

A common assumption in heat and mass transfer modelling of processes such as chilling and freezing is to consider water activity (aw) being constant or equal to 1. However, this constant value assumption does not represent the actual variation of water activity during the process. In the present work, the effect of different values of water activity on the freezing\\/thawing

A. E. Delgado; Da-Wen Sun

2007-01-01

108

Influence of the rate and the share of water freezing on hydrogen and oxygen isotope separation  

Microsoft Academic Search

The influence of the rate v and the share of freezing water g on the separation of deuterium D and oxygen 18O was studied by mass spectrometry. Evidence was obtained supporting the well known facts that upon freezing of water, (1)\\u000a the concentration of D in ice is higher than in water; (2) the degree of separation for D is

K. L. Danilov; N. L. Lavrik; V. V. Boriskin; G. A. Fokin

2009-01-01

109

Use of the soil freezing charactertistic to model frozen and unfrozen soil water dynamics  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soil moisture characteristic is critical to accurately simulate soil water dynamics but is difficult to measure, particularly for the dry regions of the curve. The relation between freezing soil temperatures, soil water potential and liquid water content, termed the soil freezing characteristic...

110

THE URANIUM HEXAFLUORIDE-HYDROGEN FLUORIDE FREEZING POINT CURVE AND ITS APPLICATION TO A METHOD OF ANALYSIS  

Microsoft Academic Search

The freezing point curve for the system uranium hexafluoride--hydrogen ; fluoride was determined over the range 0.0 to 0.6 wt% hydrogen fluoride and is ; represented by the equation wt% HF = 0.0841 DELTA t + 0.1020 DELTA t² -- ; 0.1046 DELTA t³ + 0.0363 DELTA t⁴ where DELTA t is the depression ; of the freezing point of

R. J. Wertz; W. D. Hedge

1960-01-01

111

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

112

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  

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

113

Evaluation of a Freeze-Concentration Technique for Enrichment of Natural Organic Substances in Water  

Microsoft Academic Search

A freeze concentration method was tested for its ability to concentrate uncharacterized organic carbon, measured by TOC analyzer, in tap water derived from a surface water reservoir in eastern Massachusetts. Freeze concentration was carried out in polypropylene bottles of 2 liter volume, stirred at either 140 rpm or 400 rpm, and placed in a freezer at either -15°C or -25°C.

Shahnaz Islam; Harold F. Hemond

1991-01-01

114

Molecular dynamics simulation of the ice nucleation and growth process leading to water freezing  

Microsoft Academic Search

Upon cooling, water freezes to ice. This familiar phase transition occurs widely in nature, yet unlike the freezing of simple liquids, it has never been successfully simulated on a computer. The difficulty lies with the fact that hydrogen bonding between individual water molecules yields a disordered three-dimensional hydrogen-bond network whose rugged and complex global potential energy surface permits a large

Masakazu Matsumoto; Shinji Saito; Iwao Ohmine

2002-01-01

115

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

116

State diagram of dates: Glass transition, freezing curve and maximal-freeze-concentration condition  

Microsoft Academic Search

The state diagram of Deglet Nour dates was developed using freezing curve, glass transition line, and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry (DSC) as a function of water content. Freezing points were fitted to the Clausius–Clapeyron equation adjusted with un-freezable water, and glass transition was fitted to the Gordon–Taylor model. Glass transition

Nejib Guizani; Ghalib Said Al-Saidi; Mohammad Shafiur Rahman; Salwa Bornaz; Ahmed Ali Al-Alawi

2010-01-01

117

Soil water content and freezing temperature affect freeze–thaw related N 2 O production in organic soil  

Microsoft Academic Search

An organic agricultural soil was exposed to freeze–thaw cycles (FTC) using either intact soil cores or cores packed with homogenized soil. The cores were first exposed to two mild FTCs (–1.5?°C\\/+4?°C) with soil water content being 56–85% of the water-filled pore space (WFPS). Both intact and packed soil cores showed high N2O emissions when the soil was thawing and had

Hannu T. Koponen; Pertti J. Martikainen

2004-01-01

118

Simultaneous effects of salted water and water flow on asphalt concrete pavement deterioration under freeze–thaw cycles  

Microsoft Academic Search

The presence of water flow on road surfaces may lead to early deterioration of bituminous pavements. The adverse impacts of various anti-freezing materials on road surface performance have drawn the attention of many researchers. However, the simultaneous effects of salted water and water flow on the deterioration of road surfaces, particularly under freeze–thaw conditions, have not been adequately addressed. This

Behnam Amini; Saleh Sharif Tehrani

2012-01-01

119

Computational fluid dynamics simulations of jet fuel flow near the freeze point temperature  

NASA Astrophysics Data System (ADS)

Under low-temperature environmental conditions, the cooling of aircraft fuel results in reduced fluidity with the potential for freezing. Therefore, it is important to study the flow and heat transfer phenomena that occur in an aircraft fuel tank near the freeze point temperature of jet fuels. The purpose of this dissertation is to study the effects of low temperatures on the flow, heat transfer and freezing of commercial and military jet fuels. The research is accomplished with the help of computational models of a thermal simulator tank and a quartz duct. Experimental results with the thermal simulator tank show that fuel flowability and pumpability decrease substantially as temperature is reduced. Time-dependent temperature and velocity distributions were numerically simulated for static cooling. Measured properties were used in all the computational fluid dynamics simulations. The calculations show that stringers, ribs, and other structures strongly promote fuel cooling. Also, the cooler, denser fuel resides near the bottom surface of the fuel tank simulator. The presence of an ullage space within the tank was found to strongly influence the fuel temperature profile by sometimes reducing cooling from the upper surface. Moreover, since the presence of ullage space is an explosion risk, some military aircraft fuel tanks are fitted with explosion suppressant polyurethane foam. To study the effect of foam on the flowability and heat transfer inside the simulator tank, the wing tank thermal simulator was filled with military specified polyurethane foam. The tank was simultaneously drained and cooled and the mass flow rate results showed that flowability of the fuel is not affected by the presence of foam. However, the presence of foam certainly affected the heat transfer phenomenon inside the fuel tank when the simulator tank was cooled and drained simultaneously. To study the freezing behavior of jet fuel under forced flow conditions, a quartz duct was fabricated. The duct walls were cooled below the solidification temperatures of JP-8 and JPTS fuel samples. Freezing was also simulated using computational fluid dynamics, and the validity of the calculations was established by comparing them with experimental measurements. This work demonstrates that computational fluid dynamics techniques can potentially be used to predict fuel hold-up in aircraft fuel tanks. The effect of flow rate on solidification was also simulated, and it was found that lower flow rates result in relatively more solidification of the fuel than do higher flow rates. The simulations of the freezing behaviors of JP-8 and JPTS samples were found to have essentially the same value of morphology constant. However, the crystal structures of these two fuels were studied in experiments and were found to be very different. This shows the inability of the model to capture small-scale details like the crystal microstructure. However, this limitation is not fatal here because the focus is on the overall flow and freezing behavior of jet fuels. The model was successful in predicting the freezing behavior by comparing the calculated frozen area obtained by the model with the measured area.

Assudani, Rajee

120

Influence of the Freezing and Annealing Conditions on the Realization of Cryogenic Triple Points  

NASA Astrophysics Data System (ADS)

As a basis for evaluating the results of an international star comparison of sealed fixed-point cells, dedicated investigations have been directed to the dependence of the melting temperature on different conditions concerning the preparation of the solid phase, i.e., fast and slow freezing, refreezing without supercooling, or annealing at a temperature of only a few mK below the melting temperature. Differences in the typical thermophysical behavior of the four fixed-point substances hydrogen, neon, oxygen, and argon have been found. In the case of hydrogen and oxygen, the quality of the crystal lattice has little influence on the melting temperature. This enables temperature widths of the melting curves of only a few tens of ?K, if there are no additional influences. On the contrary, argon samples frozen after supercooling with different velocities of freezing typically melt within a range of 0.3 mK. The melting-curve width can be reduced only by refreezing. A broader melting range of a few tenths of mK has been typically observed for neon cells. Unlike argon, an improvement of the crystal quality by a slow refreezing does not decrease the width of the melting-curve.

Wolber, L.; Fellmuth, B.

2008-02-01

121

Freeze separation of salt contaminated melt water and sand wash water at snow storage and sand recycling facilities  

Microsoft Academic Search

Freeze separation is used to concentrate dilute salt in snow melt water and sand recycling wash water into concentrated brine that will be supplemented with crystal salt to treat recycled road sand. This reuse decreases the salt released to the environment. Field observations from a case study of a snow storage site in Edmonton, Albert, Canada confirmed freeze separation naturally

Christina Tatarniuk; Robert Donahue; David Sego

2009-01-01

122

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

We have measured the heat flux accompanying the melting or freezing of metal (or metalloid)-carbon eutectics, using differential scanning calorimetry (DSC) to identify appropriate binary systems for secondary thermometry fixed points. Well-known alloy systems such as Fe-C and Ni-C showed reproducible endothermic and exothermic peaks that represent melting and freezing reactions in the DSC measurement. Furthermore, a new Si-C system with a eutectic composition showed reproducible melting and freezing peaks in the DSC measurements. Based on the results by DSC, we identified the Si-SiC eutectic point as a possible eutectic fixed point. To confirm this possibility, we made a Si-SiC cell for thermocouple thermometry and measured its melting and freezing characteristics using a Pt/Pd thermocouple. The melting temperature of the Si-SiC eutectic was reproducible to within 0.02 °C (one standard deviation). From the results, we found that Si-SiC has possibility as a new eutectic fixed point at temperatures around 1400 °C. We also concluded that DSC analysis could be used to measure the reproducibility of freezing and melting reactions that are to be used as fixed points for thermometry, because it is a rapid and easy-to-use tool for characterizing the thermal behaviour of materials with only a small sample.

Kwon, Su Yong; Kim, Yong-Gyoo; Yang, Inseok

2010-06-01

123

Freeze-Thaw Processes and Soil Chemistry.  

National Technical Information Service (NTIS)

This review broadly examines the interactions between freeze-thaw processes and soil chemistry, focusing on (1) the effect of solutes on physical properties such as freezing-point depression, unfrozen water and frost heaving, (2) the effect of freeze-thaw...

G. M. Marion

1995-01-01

124

Effect of water activity on sugar crystallization and ?-carotene stability of freeze-dried mango powder  

Microsoft Academic Search

Storage water activity (aw) affects the stability of freeze-dried food. The sugar crystallization and storage stability of ?-carotene in freeze-dried mango powder was investigated following storage under various relative vapor pressures (11.3–80.9%). Sugar crystallization was revealed by the loss of sorbed water in the water sorption experiment. However, the sorption isotherms showed unclear divergence between the experimental and predicted values.

Nathdanai Harnkarnsujarit; Sanguansri Charoenrein

2011-01-01

125

Application of high pressure, induced by water freezing, to the direct asymmetric aldol reaction  

Microsoft Academic Search

High pressure, induced by water freezing, has been successfully applied to the direct catalytic asymmetric aldol reaction, in which higher yield and better enantioselectivity can be realized than in the reaction at room temperature under 0.1MPa.

Yujiro Hayashi; Wataru Tsuboi; Mitsuru Shoji; Noriyuki Suzuki

2004-01-01

126

The Baylis–Hillman reaction under high pressure induced by water-freezing  

Microsoft Academic Search

High pressure (about 200 MPa), which was realized by freezing water in a sealed autoclave, has been successfully applied to the Baylis–Hillman reaction, in which an efficient rate enhancement was observed.

Yujiro Hayashi; Kotaro Okado; Itaru Ashimine; Mitsuru Shoji

2002-01-01

127

Study of Freezing and Vacuum Flashing to Recover Acetone from Acetone-Water-Energetic Mixtures.  

National Technical Information Service (NTIS)

In this work, thermodynamic data is obtained on acetone-water-energetic mixtures. Also, two processes, freezing and flashing, are evaluated for recovery of acetone from the mixtures. The specific energetic compounds used in this work are dinitrotoulene an...

R. Boggavarapu G. G. Chase

1995-01-01

128

Freezing Risk for Water Mains in Frozen Ground (Undersokning av Frysrisken for Vattenledninger Ovanfor Tjalgransen).  

National Technical Information Service (NTIS)

In the autumn of 1971 an experimental plant was installed at Forslunda water-works, Umea. The purpose was to verify experimentally the risk for freezing of insulated and uninsulated asbestos-cement pipes according to theoretical calculations regarding lay...

L. E. Janson

1977-01-01

129

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

PubMed

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

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

2013-01-11

130

Acquisition of freezing tolerance in early autumn and seasonal changes in gall water content influence inoculative freezing of gall fly larvae, Eurosta solidaginis (Diptera, Tephritidae)  

Microsoft Academic Search

We examined seasonal changes in freeze tolerance and the susceptibility of larvae of the gall fly, Eurosta solidaginis to inoculative freezing within the goldenrod gall (Solidago sp.). In late September, when the water content of the galls was high (~55%), more than half of the larvae froze within their galls when held at –2.5 °C for 24 h, and nearly

R. E. Lee Jr; S. J. Hankison

2003-01-01

131

Effect of freezing temperature, thawing and cooking rate on water distribution in two pork qualities  

Microsoft Academic Search

The effects of freezing temperature (?20 versus ?80°C) in combination with long-term freezer storage (?20°C) on water mobility and distribution in pork of two qualities (normal and high ultimate pH) were explored using low-field NMR T2 relaxometry. A marked effect of freezing temperature on the characteristics of intra- and extramyofibrillar water (T2 relaxation times) in the thawed pork was demonstrated,

Margit Mortensen; Henrik Jørgen Andersen; Søren Balling Engelsen; Hanne Christine Bertram

2006-01-01

132

Water freezes differently on positively and negatively charged surfaces of pyroelectric materials.  

PubMed

Although ice melts and water freezes under equilibrium conditions at 0 degrees C, water can be supercooled under homogeneous conditions in a clean environment down to -40 degrees C without freezing. The influence of the electric field on the freezing temperature of supercooled water (electrofreezing) is of topical importance in the living and inanimate worlds. We report that positively charged surfaces of pyroelectric LiTaO3 crystals and SrTiO3 thin films promote ice nucleation, whereas the same surfaces when negatively charged reduce the freezing temperature. Accordingly, droplets of water cooled down on a negatively charged LiTaO3 surface and remaining liquid at -11 degrees C freeze immediately when this surface is heated to -8 degrees C, as a result of the replacement of the negative surface charge by a positive one. Furthermore, powder x-ray diffraction studies demonstrated that the freezing on the positively charged surface starts at the solid/water interface, whereas on a negatively charged surface, ice nucleation starts at the air/water interface. PMID:20133568

Ehre, David; Lavert, Etay; Lahav, Meir; Lubomirsky, Igor

2010-02-01

133

Isotope quantum effects in water around the freezing point  

Microsoft Academic Search

We have measured the difference in electronic structure factors between liquid H2O and D2O at temperatures of 268 and 273 K with high energy x-ray diffraction. These are compared to our previously published data measured from 279 to 318 K. We find that the total structural isotope effect increases by a factor of 3.5 over the entire range, as the

R. T. Hart; Q. Mei; C. J. Benmore; J. C. Neuefeind; J. F. C. Turner; M. Dolgos; B. Tomberli; P. A. Egelstaff; SUF-USR

2006-01-01

134

Relationship between swollen network structure of rubber vulcanizates and mechanism of freezing point depression of swelling solvent  

Microsoft Academic Search

In order to investigate the mechanism of freezing point depression (FPD) phenomena for polymer solutions and\\/or swollen rubber vulcanizates, some experiments related to this phenomenon have been carried out at a constant rate of cooling and at low temperatures. Thus far this phenomenon has not been explainable in terms of an ordinary colligative effect. In this study a new mechanism

H. Oikawa; K. Murakami

1989-01-01

135

Haline Convection Induced by the Freezing of Sea Water  

Microsoft Academic Search

for the time necessary for the onset of manifest convective behavior and the horizontal spacing of the convection cells are derived for various manners of increasing the salinity at the top surfaces. For molecular coefficients of viscosity and diffusion and cooling conditions that may be appropriate for the freezing season in the Antarctic it is found that the initial horizontal

Theodore D. Foster

1968-01-01

136

A comparative study of freeze-thaw processes for conditioning wastewater and water treatment sludges  

SciTech Connect

This research effort involved the application of indirect- and direct-contact, freeze-thaw conditioning techniques for improving the dewatering characteristics of both waste water and water treatment sludges. Sludges tested included waste activated sludge, primary sewage sludge, waste activated/primary sewage sludge mixtures and alum sludge. The direct-freeze methods examined were the use of a secondary refrigerant (butane) evaporated in the sludge and the use of gas hydrate or clathrate formation by addition of Freon 12 under appropriate temperature and pressure conditions. Sludges were also frozen solid using indirect freezing methods, thawed and tested for comparative purposes. Particle size distribution and floc density measurements were used to determine changes in particle characteristics; specific resistance values and dewatered dry solids concentration were used to assess dewatering characteristics. Results of direct and indirect-contact, freeze-thaw conditioning were compared to the effects of polymer conditioning. The results indicated that direct-freeze methods do not appear technically or economically competitive with currently accepted conditioning methods. The superior results obtained with the indirect-contact, freeze-thaw process when compared to the direct-contact processes suggested that the extent and rate of freezing may greatly influence the particle characteristics of the conditioned sludge, and thus its dewatering characteristics.

Trahern, P.G.

1989-01-01

137

Supercooling and the Mpemba effect: When hot water freezes quicker than cold  

Microsoft Academic Search

Temperature measurements taken near vessel walls show that initially hot water may well begin to freeze quicker than cold. This is not, as previously surmised, due to the cooling history of the water (e.g., air expulsion during heating). Rather, supercooling virtually always takes place. On those occasions where the cold water supercools sufficiently more than the hot the Mpemba scenario

David Auerbach

1995-01-01

138

Using soil freezing characteristics to model multi-season soil water dynamics  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soil moisture characteristic relation is critical to accurately simulate soil water dynamics but is difficult and time consuming to measure, particularly for the dry regions of the curve. The relation between freezing soil temperatures, soil water potential and liquid water content, termed the ...

139

Effects of freezing in and out of water on length and weight of Lake Michigan bloaters  

USGS Publications Warehouse

The purpose of this study was to determine if freezing significantly alters the length or weight of bloaters Coregonus hoyi. Bloaters were collected from southern Lake Michigan and were frozen for periods of 2-200 d. Freezing in water caused a significant decrease in length and a significant increase in weight. These changes did not vary predictably with time. The mean change in weight was greater for adults than for juveniles, but the mean change in length was not significantly different between juveniles and adults. Regressions for weight or length after freezing versus weight or length before freezing were highly significant and can be used as correction equations for estimating the original lengths and weights of fresh specimens after fish have been frozen. Test fish that were subsequently refrozen in air shrank more than those refrozen in water.

Sayers, Richard E.

1987-01-01

140

Freeze concentration for enrichment of nutrients in yellow water from no-mix toilets.  

PubMed

Separately collected urine ("yellow water") can be utilized as fertilizer. In order to decrease storage volumes and energy consumption for yellow water transport to fields, enrichment of nutrients in yellow water has to be considered. Laboratory-scale batch freeze concentration of yellow water has been tested in ice-front freezing apparatus: a stirred vessel and a falling film freeze concentrator (coolant temperatures: -6 to -16 degrees C). With progressing enrichment of the liquid concentrate, the frozen ice was increasingly contaminated with yellow water constituents (ammonia, total nitrogen, total phosphorus, TOC, and salts determined as conductivity). The higher the initial salinity of the yellow water and the lower the mechanical agitation of the liquid phase contacting the growing ice front, the more the frozen ice was contaminated. The results indicate, that in ice-front freezing devices multistage processes are necessary, i.e. the melted ice phase has to be purified (and the concentrates must be further enriched) in a second or even in a third stage. Energy consumption of this process is very high. However, technical scale suspension freeze concentration is reasonable in centralized ecological sanitation schemes if the population exceeds 0.5 million and distance of yellow water transportation to fields is more than 80 km. PMID:15536991

Gulyas, H; Bruhn, P; Furmanska, M; Hartrampf, K; Kot, K; Lüttenberg, B; Mahmood, Z; Stelmaszewska, K; Otterpohl, R

2004-01-01

141

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, January 1March 31, 1993  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable climatic conditions.

J. Boysen; J. Morotti

1993-01-01

142

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, April 1June 30, 1993  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive natural conditions freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable

J. Boysen; J. Morotti

1993-01-01

143

Acquisition of freezing tolerance in early autumn and seasonal changes in gall water content influence inoculative freezing of gall fly larvae, Eurosta solidaginis (Diptera, Tephritidae).  

PubMed

We examined seasonal changes in freeze tolerance and the susceptibility of larvae of the gall fly, Eurosta solidaginis to inoculative freezing within the goldenrod gall (Solidago sp.). In late September, when the water content of the galls was high (approximately 55%), more than half of the larvae froze within their galls when held at -2.5 degrees C for 24 h, and nearly all larvae froze at -4 or -6 degrees C. At this time, most larvae survived freezing at > or = -4 degrees C. By October plants had senesced, and their water content had decreased to 33%. Correspondingly, the number of larvae that froze by inoculation at -4 and -6 degrees C also decreased, however the proportion of larvae that survived freezing increased markedly. Gall water content reached its lowest value (10%) in November, when few larvae froze during exposure to subzero temperatures > or = -6 degrees C. In winter, rain and melting snow transiently increased gall water content to values as high as 64% causing many larvae to freeze when exposed to temperatures as high as -4 degrees C. However, in the absence of precipitation, gall tissues dried and, as before, larvae were not likely to freeze by inoculation. Consequently, in nature larvae freeze earlier in the autumn and/or at higher temperatures than would be predicted based on the temperature of crystallization (T(c)) of isolated larvae. However, even in early September when environmental temperatures are relatively high, larvae exhibited limited levels of freezing tolerance sufficient to protect them if they did freeze. PMID:12769992

Lee, R E; Hankison, S J

2003-04-01

144

Freezing tolerance and water relations of Opuntia fragilis from Canada and the United States  

SciTech Connect

To investigate the influence of winter climate on freezing tolerance at the population level, minimum January air temperatures in the field and cold acclimation determined in the laboratory were compared for Opuntia fragilis. Populations occurred at 20 locations as far north as 56[degrees]46' N latitude and at elevations up to 3029 m in Canada and the United States, most of which experience extreme freezing temperatures each winter. Low-temperature responses and water relations of stems were examined in the laboratory at day/night air temperatures of 25[degrees]/15[degrees]C and 14 d after the plants were shifted to a 5[degrees]/[minus]5[degrees]C temperature cycle. Cold acclimation averaged 17[degrees]C and freezing tolerance averaged [minus]29[degrees]C for the 20 populations following a shift to low day/night air temperatures, indicating that O. fragilis has the greatest cold acclimation ability and the greatest freezing tolerance reported for any cactus. Moreover, freezing tolerance and cold acclimation were both positively correlated (r[sup 2] [congruent] 0.7) with the minimum temperatures at the 20 locations. Plants lost water during low-temperature acclimation, leading to 30% decreases in cladode and chlorenchyma thickness; the decrease in water content was greater for the five warmest populations than for the five coldest ones. Over the same period, the average osmotic pressure of the chlorenchyma increased from 1.42 to 1.64 MPa, and the relative water content (RWC) decreased from 0.58 to 0.49, but the average osmotic pressure of saturated chlorenchyma was unchanged, indicating no net change in solute content during acclimation. Although the role of water relations in freezing tolerance is unclear, the substantial freezing tolerance and cold acclimation ability of O. fragilis leads to its distribution into regions of Canada and the United States that experience minimum temperatures below [minus]40[degrees]C during the winter. 47 refs., 3 figs., 5 tabs.

Loik, M.E.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

1993-09-01

145

Freezing of Confined Water: A Bilayer Ice Phase in Hydrophobic Nanopores  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations were performed to study the phase behavior of a thin film of water confined to a slit nanopore with smooth walls. A first-order water-to-ice freezing transition has been observed. The resulting ice, which is a crystal of bilayer consisting of rows of distorted hexagons, does not resemble any ice crystals found so far. The confined water contracts upon freezing when the confinement load is low ( ~0.5 kbar) and expands when the load is high (10 kbar). The residual entropy of the bilayer ice can be calculated exactly, which is about half of the entropy of the bulk ice.

Koga, Kenichiro; Zeng, X. C.; Tanaka, Hideki

1997-12-01

146

Estimate of Phase Transition Water Content in Freeze–Thaw Process Using Microwave Radiometer  

Microsoft Academic Search

Ground surface freeze-thaw cycles caused by changes in solar radiation have a great impact on soil-air water heat exchanges due to the phase transition of pore water. This influence should not be ignored in the land surface process and global environment change studies because of its large extent and the rapid changes in daily and seasonal frozen ground. The key

Lixin Zhang; Tianjie Zhao; Lingmei Jiang; Shaojie Zhao

2010-01-01

147

Laboratory investigation on freeze separation of saline mine waste water  

Microsoft Academic Search

The extraction and upgrading process for bitumen from oil sand deposits in Alberta, Canada currently requires large volumes of process water. This water demand is fulfilled by importing water and recycling\\/reuse of clarified process water. Reuse of the clarified water results in the steady increase of organic and inorganic (salt) contaminant concentrations in the recycle water. Using a specially designed

Nicholas Beier; David Sego; Rob Donahue; Kevin Biggar

2007-01-01

148

In situ freeze-capturing of fracture water using cryogenic coring  

SciTech Connect

Current methods do not allow for sampling of in situ water from unsaturated fractures in low-moisture environments. A novel cryogenic coring technique based on the method developed by Simon and Cooper (1996) is used to collect in situ water in unsaturated fractures. This method uses liquid nitrogen as the drilling fluid, which can freeze the fracture water in place while coring. Laboratory experiments are conducted to demonstrate that water in an unsaturated fracture can be frozen and collected using cryogenic coring.

Su, Grace W.; Wang, Joseph S.Y.; Zacny, Kris

2004-01-29

149

Water sorption and time-dependent crystallization behaviour of freeze-dried lactose–salt mixtures  

Microsoft Academic Search

Water sorption properties of freeze-dried lactose, lactose\\/CaCl2, lactose\\/NaCl, lactose\\/MgCl2, and lactose\\/KCl mixtures in their molar ratio of (9:1) were investigated. Brunauer–Emmett–Teller (BET) and Guggenheim–Anderson–de Boer (GAB) models were used to model water sorption properties. Water is known to function as a plasticizer, depressing the glass transition and facilitating crystallization. Crystallization in the present study resulted in loss of sorbed water

A. M. Elmonsef Omar; Yrjö H. Roos

2007-01-01

150

100% freeze protection for thermosiphon solar water heaters  

SciTech Connect

Solar collectors must be prevented from suffering damage from freezing to become accepted in almost all of the United States. Use of heat exchangers and non-aqueous fluids present serious cost, performance and safety considerations. Development of and inherently freeze protected solar collector to be used in a thermosyphon system is critical for solar energy to become a significant source of energy for residential thermal needs. This project investigates a technique of accomplishing this end by the use of a compliant member inside the tubing of the solar collector and associated supply and return piping. The compliant element is a length of plastic tubing selected for its suitable physical properties for use in a solar collector. The tubing was prepressurized and the tubing then sealed a fixed intervals to provide a safety factor in case there is a failure or leak in the tubing. This report presents the methods used to test the ideas and the results of the construction and testing of a full scale system utilizing this concept.

Leonaitis, L.

1983-12-01

151

Some spectroscopic and freezing point depression measurements on the homogeneous hydrogenation catalyst CoH 3 (PPh 3 ) 3  

Microsoft Academic Search

NMR, EPR and freezing point depression (FPD) experiments were performed on solutions of the homogeneous hydrogenation catalyst CoH3(PPh3)3. The results of these measurements show that the compound has a dynamic structure on the NMR time scale at room temperature and that it is slightly dissociated into bisphosphine species and free phosphine. FPD and1H-NMR measurements indicate that one Et2O molecule is

J. L. Hendrikse; J. W. E. Coenen; A. W. P. G. Peters Rit

1975-01-01

152

FIELD DEPLOYMENT EVALUATION OF THE FREEZE-THAW/EVAPORATION (FTE) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS. Task 45. Final topical report.  

National Technical Information Service (NTIS)

TASK 45 FIELD DEPLOYMENT EVALUATION OF THE FREEZE THAW/ EVAPORATION (FTE ) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS coupling evaporation with freezing. This offers operators a year- round method for treating produced water. Treating water with the FTE...

A. A. Grisanti J. A. Sorensen

1999-01-01

153

MOST CURRENT WATER QUALITY STANDARDS - POINT EVENTS  

EPA Science Inventory

State Water Quality Standards' Designated Uses for river segments, lakes, and estuaries. Most current Water Quality Standards coded onto route.rch (Transport and Coastline Reach) feature of the National Hydrography Dataset (NHD) to create NHD - Point Events. Point events are...

154

Vitrification of pure liquid water by high pressure jet freezing  

Microsoft Academic Search

The vitrification of pure liquid water by projecting a thin jet of liquid water at high speed into a liquid cryomedium is reported. The influence of the experimental parameters on the cooling rate and the devitrification of the jet-frozen vitrified material have been investigated. A structural difference between vitrified liquid water and amorphous solid water prepared from the vapour phase

Erwin Mayer; Peter Brüggeller

1982-01-01

155

Freezing of the thawed zone around a well in frozen soils taking into account the pressure-dependence of the temperature of freezing  

NASA Astrophysics Data System (ADS)

The effects of taking into account the drop in the freezing point of water in the calculation of the pressures of retrograde freezing, arising during idle time and temporary shut-down of wells in frozen soils, are analyzed.

Dubina, M. M.; Krasovitskii, B. A.

1985-01-01

156

Avoid freeze-up of steam traps and their piping  

Microsoft Academic Search

This article addresses the problem of keeping steam traps free of ice in cold weather. The topics of the article include piping configurations and trap types that contribute to freezing, freeze damage, obstructions in piping, insulation of lines to retard freezing, common manifolds for heating of condensate, draining of low points, temperature-actuated devices, and water hammer damage.

OKeefe

1993-01-01

157

Avoid freeze-up of steam traps and their piping  

SciTech Connect

This article addresses the problem of keeping steam traps free of ice in cold weather. The topics of the article include piping configurations and trap types that contribute to freezing, freeze damage, obstructions in piping, insulation of lines to retard freezing, common manifolds for heating of condensate, draining of low points, temperature-actuated devices, and water hammer damage.

O'Keefe, W.

1993-12-01

158

Solutions : FreezePtDepression (20 Variations)  

NSDL National Science Digital Library

It takes 6.86 kg of ethylene glycol (antifreeze) to decrease the freezing point of 6.50 kg of water to -25.0 o F (-31.7 o C). How much sodium chloride (NaCl) would it take to decrease the freezing point of 6.50 kg of water to -25.0 o F? (Assuming all the salt will dissolve in that amount of water.)

159

Effect of nucleation agents on the freezing probability of supercooled water inside capsules  

SciTech Connect

The effect of nucleation agents on the freezing probability of supercooled water inside cylindrical capsules during a cold storage process was investigated. Different types of nucleation agents including silver iodide (AgI), lead iodide (PbI{sub 2}), river sand, and mud powder were used to achieve water nucleation under different coolant temperatures. The effect of the amount of nucleation agents on the freezing probability of cylindrical capsules was studied. The results indicate that the nucleation probability and nucleation temperature of supercooled water inside capsules adding nucleation agents are higher than those of capsules containing pure water only, which suggests that nucleation agents are effective in reducing supercooling of water. Of the nucleation agents used, silver iodide showed the best results in facilitating the nucleation. However, river sand is recommended as the nucleation agent because it is the most inexpensive and effective for the type of encapsulated storage tank used in a cold storage air-conditioning system.

Chen, S.L.; Chen, C.L.

2000-07-01

160

Measurement of Water Transport during Freezing in Cell Suspensions Using a Differential Scanning Calorimeter  

Microsoft Academic Search

A new technique using a differential scanning calorimeter (DSC) was developed to obtain dynamic and quantitative water transport data in cell suspensions during freezing. The model system investigated was a nonattached spherical lymphocyte (Epstein–Barr virus transformed, EBVT) human cell line. Data from the technique show that the initial heat release of a prenucleated sample containing osmotically active cells in media

Ramachandra V. Devireddy; Debopam Raha; John C. Bischof

1998-01-01

161

Simulation of the Process of Water Freezing in a Round Pipe  

Microsoft Academic Search

The problem of freezing of pure water in a round pipe is treated with due regard for convection under asymmetric thermal boundary conditions in the absence of motion along the pipe. The problem is solved numerically using the control volume approach, SIMPLER algorithm, and the enthalpy method. Results are obtained for three Grashof (Gr) and six Biot (Bi) numbers: Gr

P. T. Zubkov; V. A. Kravchenko; E. M. Sviridov

2001-01-01

162

Study of melting and freezing processes of water for application to ice thermal energy storage system  

Microsoft Academic Search

This thesis presents the results of a study of the solid-liquid phase change process of water in a rectangular enclosure for application to thermal energy storage systems. The work performed combined experimental results with analytical and numerical methods to develop computer models of the system. Experiments were performed to obtain data to verify the models under various melting and freezing

Liang Yong

1993-01-01

163

Dynamic mechanical measurements on fresh-water ice during freezing and thawing: preliminary results  

Microsoft Academic Search

An automated measurement system for elastic (J' ) and viscous (J'' ) components of complex shear compliance, J* = J' - iJ'', and the elastic (G' ) and viscous (G'' ) components of complex shear modulus, G* = G' + iG'' = 1\\/J*, has been used to obtain these material parameters for fresh-water ice during freezing and thawing. The system

E. R. Fitzgerald

2003-01-01

164

Design of a Eutectic Freeze Crystallization process for multicomponent waste water stream  

Microsoft Academic Search

Complex, hypersaline brines originating from the mining and extractive metallurgical industries have the potential to be treated using Eutectic Freeze Crystallization (EFC). Although EFC has been shown to be effective in separating a single salt and water, it has yet to be applied to the complex hypersaline brines that are typical of reverse osmosis retentates in South Africa. This paper

A. E. Lewis; J. Nathoo; K. Thomsen; H. J. Kramer; G. J. Witkamp; S. T. Reddy; D. G. Randall

2010-01-01

165

Experimental investigation of freezing blowby in a copper\\/water heat pipe  

Microsoft Academic Search

An experimental investigation designed to evaluate and better define the overall characteristics of freezing blowby in a copper\\/water heat pipe was conducted. The results from various rates of restart heat addition and channel blockage, indicate that upon breakthrough the depressurization of the evaporator may result in an effective heat transport capacity far in excess of the steady-state transport limit. The

J. M. Ochterbeck; G. P. Peterson

1992-01-01

166

Freeze-out of salts in hard-water lakes  

Microsoft Academic Search

A 1Syear series of daily measurements of pH and total alkalinity recorded at the water intake of a municipal water-treatment plant on Clear Lake, Iowa, demonstrated that rapid chemical changes occur annually as the ice cover melts. Additional measurements of total and calcium hardness on this and three other eutrophic, hard-water lakes showed that total and calcium hardness concentrations declined

DANIEL E. CANFIELD; ROGER W. BACHMANN; MARK V. HOYER

1983-01-01

167

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

SciTech Connect

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, .

Wang, J. [University of Nebraska, Lincoln; Apte, Pankaj [Indian Institute of Technology, Kanpur; Morris, James R [ORNL; Zeng, X.C. [University of Nebraska, Lincoln

2013-01-01

168

Water relations in freeze-dried powdered shortenings from babassu fat  

Microsoft Academic Search

Shortening powders are simple, versatile and convenient ways to enhance functional properties of foods. The objective of this study was to evaluate the water relations of shortening powders, produced by freeze-drying emulsions. Shortening powders were obtained by drying oil-in-water emulsions of skim milk solids and babassu fat, with no added emulsifier, by lyophilization. The hygroscopic behaviour of the shortening powders

L. A. Gioielli; R. N. M. Pitombo; A. M. Pinheiro; A. M. T. M. Balbo

1998-01-01

169

Mpemba effect and phase transitions in the adiabatic cooling of water before freezing  

Microsoft Academic Search

In this paper, an accurate experimental investigation of the Mpemba effect (that is, of the fact that initially hot water freezes before the colder one) is carried out, showing that, in the adiabatic cooling of water, relevant roles are played by supercooling, and by phase transitions which take place at 6±1 ?C,3.5±0.5 ?C and 1.3±0.6 ?C. The last transition, which occurs with the

S. Esposito; R. De Risi; L. Somma

2008-01-01

170

Magnetic resonance imaging of water freezing in packed beds cooled from below  

Microsoft Academic Search

Full-field quantitative visualization of freezing interfaces requires the introduction of high resolution noninvasive methods. Magnetic resonance imaging (MRI) is a versatile tool for mapping the distribution of liquids (primarily water) in three-dimensional space, and is the only practical solution in systems that are strongly refracting or opaque to visible light. MRI is employed to visualize ice formation in water-saturated packed

John G. Georgiadis; Mahadevan Ramaswamy

2005-01-01

171

Freezing points and small-scale deicing tests for salts of levulinic acid made from grain sorghum.  

PubMed

Deicers from renewable resources are needed to overcome the disadvantages of using traditional deicers. Salts made from levulinic acid produced using grain sorghum as raw material were tested as road deicing agents. Freezing points of these salts viz., sodium levulinate, magnesium levulinate and calcium levulinate along with rock salt (sodium chloride) were determined according to American Society for Testing and Materials (ASTM) D 1177-94 standard at concentrations of 10, 20, 30 and 40 % w/w. There were significant differences among the freezing points of the salts. Freezing points for rock salt, sodium levulinate, calcium levulinate and magnesium levulinate, for different concentrations, were in the ranges of -6.6 to -20.5, -2.9 to -15.0, -2.1 to -7.8 and -1.5 to -6.5 degrees C, respectively. Deicing effectiveness of the salts of levulinic acid were investigated by conducting small-scale deicing tests with aqueous solutions of various salt concentrations (2%, 5% and 10%) in a laboratory freezer and by spraying the deicer on a graveled surface covered by ice and snow with the average temperature during the testing at -2.7 degrees C. Deicing capabilities of the three salts of levulinic acid differed. At -2.7 degrees C, all three salts caused melting of the ice. Among the different levulinates studied sodium levulinate was the most effective deicing agent. These salts of levulinates could be a viable replacement for traditional deicers and could help in reducing the disadvantages of traditional deicers. PMID:17416518

Ganjyal, G; Fang, Q; Hanna, M A

2007-04-09

172

Vacuum Freezing Multiple Phase Transformation Process Investigation.  

National Technical Information Service (NTIS)

The Vacuum Freezing Multiple Phase Transformation (VFMPT) Process accomplishes vapor liquefaction by desublimation of the vapor on a refrigerated surface, production of a second water vapor of higher temperature than the melting point of ice, and then dir...

C. Y. Cheng W. C. Cheng

1986-01-01

173

Methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status  

Microsoft Academic Search

Summary The abiotic stresses of drought, salinity and freezing are linked by the fact that they all decrease the availability of water to plant cells. This decreased availability of water is quantified as a decrease in water potential. Plants resist low water potential and related stresses by modifying water uptake and loss to avoid low water potential, accumulating solutes and

Paul E. Verslues; Manu Agarwal; Surekha Katiyar-Agarwal; Jianhua Zhu; Jian-Kang Zhu

2006-01-01

174

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1December 31, 1993  

Microsoft Academic Search

The use of freeze-crystallization processes for the treatment of contaminated water is rapidly being acknowledged as a low cost and low energy consuming method for the purification of water contaminated by a wide variety of contaminants of highly variable concentrations. Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment

J. Boysen; J. Morotti

1994-01-01

175

Freeze Concentration and Its Recent Development  

NASA Astrophysics Data System (ADS)

This article concerns freeze concentration and its recent development. Freeze concentration enables to remove water from aqueous solutions including volatile and heat-sensitive components with less damage to the concentrated solution because of the operation at lower temperature near the freezing point with possibly no gas-liquid boundary. Moreover, the lower latent heat accompanied with ice crystallization provides a possibility of the operation with lower energy consumption. Recently freeze concentration has been applied to the wastewater treatment field. First the principle of freeze concentration will be addressed. Second applications of freeze concentration to the wastewater treatment field will be reviewed, including our recent works. Finally prospective views of freeze concentration will be given.

Wakisaka, Minato; Shirai, Yoshihito

176

Thermophysical Properties of SweetPotato Puree at Freezing and Refrigeration Temperatures  

Microsoft Academic Search

The thermophysical properties (initial freezing point, unfreezable water, enthalpy of freezing, and specific heat) of alginate-restructured sweet potato (SP) puree at freezing and refrigeration temperatures were determined using differential scanning calorimetry. Restructuring of SP puree increased the amount of unfreezable (bound) water in the puree from 0.44 g H2O\\/g solids to about 0.56 g H2O\\/g solids and reduced the freezing point from

O. O. Fasina

2005-01-01

177

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996.  

National Technical Information Service (NTIS)

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced w...

J. A. Harju J. E. Boysen J. L. Mefford J. R. Kirsch K. L. Walker

1996-01-01

178

FREEZE-THAW AND WATER TENSION EFFECTS ON SOIL DETACHMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many areas of the northern United States and southern Canada, and particularly the four million ha of non-irrigated cropland in eastern Oregon and Washington, northern and southern Idaho, and northern Utah, experience severe water erosion under thawing soil conditions. Modeling soil erosion in these...

179

Infrared spectroscopy of sulfuric acid\\/water aerosols: Freezing characteristics  

Microsoft Academic Search

A low-temperature flow cell has been used in conjunction with a Fourier transform infrared (FT-IR) spectrometer to study sulfuric acid\\/water aerosols. The aerosols were generated with a wide range of composition (28 to 85 wt %), including those characteristic of stratospheric sulfate aerosols, and studied over the temperature range from 240 K to 160 K. The particles exhibited deep supercooling,

M. L. Clapp; R. F. Niedziela; L. J. Richwine; T. Dransfield; R. E. Miller; D. R. Worsnop

1997-01-01

180

Fish antifreeze protein and the freezing and recrystallization of ice.  

PubMed

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

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

181

Confined water in hydrophobic nanopores: Dynamics of freezing into bilayer ice  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations for a thin film of water confined to a slit nanopore are performed in order to investigate the dynamic process of crystallization of the system. The system upon freezing creates a bilayer ice crystal composed of two layers of hexagonal rings. We perform one simulation at T=257 K during which the system remains a supercooled liquid state, and another one at T=253 K during which the system freezes. Many patterns of molecular arrangement are found upon freezing, and an account is given of the origin of multiple peaks in the distributions of binding energy and pair interaction energy. A definition of the solidlike cluster is introduced in order to analyze the time evolution of the clusters' population and their shapes. A large variety of shapes including highly nonspherical ones can be detected during simulations. A steady population of clusters is found at T=257 K, whereas at T=253 K a post-critical nucleus of the solid phase emerges within a few nanoseconds and continues to grow until the system freezes completely.

Slovák, Jan; Koga, Kenichiro; Tanaka, Hideki; Zeng, Xiao C.

1999-11-01

182

On the stability of oil-in-water emulsions to freezing  

Microsoft Academic Search

Oil in water emulsions (40wt%) were prepared from a homologous series of n-alkanes (C10–C18). The samples were temperature cycled in a differential scanning calorimeter (two cycles of 40 °C to ?50 °C to 40 °C at 5 °C min?1) and in bulk (to ?20 °C). The emulsions destabilized and phase-separated after freeze–thaw if the droplets were solid at the same

Grace L Cramp; Andrea M Docking; Supratim Ghosh; John N Coupland

2004-01-01

183

Deep Water Single Point Mooring Design.  

National Technical Information Service (NTIS)

This report presents the results of a feasibility study of single point mooring (SPM) systems for the Mobile Offshore Base, a very large semi-submerged platform, in up to 10,000 ft (3000 m) water depth. The MOB will use the mooring in mild environments. T...

H. A. McKenna J. F. Flory

1997-01-01

184

Relationship between Recrystallization Rate of Ice Crystals in Sugar Solutions and Water Mobility in Freeze-Concentrated Matrix  

Microsoft Academic Search

To better understand the relation between recrystallization rate and water mobility in freeze-concentrated matrix, isothermal ice recrystallization rates in several sugar aqueous solutions and self-diffusion coefficients of water component in corresponding freeze-concentrated matrix were measured. The sugars used were fructose, glucose, maltose, and sucrose. The sugar concentrations and temperature were varied so that ice contents for all samples were almost

Tomoaki Hagiwara; Richard W. Hartel; Shingo Matsukawa

2006-01-01

185

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Final report, August 1992August 1996  

Microsoft Academic Search

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil

J. E. Boysen; K. L. Walker; J. L. Mefford; J. R. Kirsch; J. A. Harju

1996-01-01

186

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1, 1995--December 31, 1995  

SciTech Connect

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year-round in regions where sub-freezing temperatures seasonally occur. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas.

Boysen, J.; Morotti, J.

1996-01-01

187

Freezing tolerance and soluble sugar contents affected by water stress during cold-acclimation and de-acclimation in cabbage seedlings  

Microsoft Academic Search

The effect of water stress on freezing tolerance during cold-acclimation and de-acclimation in cabbage seedlings were studied. The seedlings were subjected to water stress by withholding water. The treatment wilted the seedlings and decreased the water content of their shoots. Exposure of seedlings to low temperatures (5°C) for 7 days induced freezing tolerance. Water stress promoted the increase in freezing

Hidekazu Sasaki; Kazuo Ichimura; Kunihiko Okada; Masayuki Oda

1998-01-01

188

Freeze-drying of tert-butanol/water cosolvent systems: a case report on formation of a friable freeze-dried powder of tobramycin sulfate.  

PubMed

A case study is presented in which a tert-butanol (TBA)/water cosolvent system was found to be a useful means of producing freeze-dried tobramycin sulfate that readily forms a loose powder upon agitation in a specialized application in which a critical quality attribute is the ability to pour the sterile powder from the vial. Both formulation and processing variables are important in achieving acceptable physical properties of the cake as well as minimizing residual TBA levels. Liquid/liquid phase separation was observed above critical concentrations of both drug and TBA, resulting in a two-layered lyophilized cake with unacceptable appearance, physical properties, and residual TBA levels. However, the choice of tobramycin sulfate and TBA concentrations in the single-phase region of the phase diagram resulted in a lyophilized solid that can readily be poured from vials. Crystallization of TBA before drying is critical to achieving adequately low residual TBA levels, and this is reflected in the effect of thermal history of freezing on residual TBA levels, where rapid freezing results in incomplete crystallization of TBA and relatively high levels of residual solvent. Annealing at a temperature above T'(g) of the system after an initial freezing step significantly reduces the level of residual TBA. Secondary drying, even at increased temperature and for extended times, is not an effective method of reducing residual TBA levels. PMID:11948553

Wittaya-Areekul, Sakchai; Needham, Gregory F; Milton, Nathaniel; Roy, Michael L; Nail, Steven L

2002-04-01

189

Dynamic mechanical measurements on fresh-water ice during freezing and thawing: preliminary results  

NASA Astrophysics Data System (ADS)

An automated measurement system for elastic (J' ) and viscous (J'' ) components of complex shear compliance, J* = J' - iJ'', and the elastic (G' ) and viscous (G'' ) components of complex shear modulus, G* = G' + iG'' = 1/J*, has been used to obtain these material parameters for fresh-water ice during freezing and thawing. The system is reviewed briefly and yields mechanical loss tangents, J''/J' = G''/G', the shear-wave velocity and attenuation, in addition to shear compliance and modulus, at sinusoidal vibration frequencies from 2 to 10 000 Hz at temperatures between -25 and 150degreesC. Results reported here are chiefly at temperatures from 10 to -10degreesC. The required sample disk pairs, which are clamped to a central drive plate, are prepared outside the apparatus for solids and gels. Liquids of known volume are inserted between the drive plate and surrounding clamps at a separation distance, h, by a syringe to form sample disks of area, A = Volume / h. Measurements at 58 frequencies between 2 and 10 000 Hz require 3.5 min; several measurements at each temperature were made to test for equilibrium. Results for both tap and distilled water above freezing revealed high values of elastic (J' ) compliance that decreased sharply at 100 Hz and higher frequencies. Tap-water samples with 4 to 6% by volume air bubbles were less compliant ("stiffer") above freezing than samples with 0 to 1% by volume air, but when frozen, the samples with the smaller volume of air bubbles were less compliant, that is, had higher modulus values than the samples with high air-bubble volumes. Dynamic mechanical property changes in the transition from water to ice are compared to changes previously found during phase transitions in other materials. Further investigation on the effects of air-bubble volumes on dynamic mechanical properties of both water and ice is planned.

Fitzgerald, E. R.

2003-01-01

190

Volume crossover in deeply supercooled water adiabatically freezing under isobaric conditions  

NASA Astrophysics Data System (ADS)

The irreversible return of a supercooled liquid to stable thermodynamic equilibrium often begins as a fast process which adiabatically drives the system to solid-liquid coexistence. Only at a later stage will solidification proceed with the expected exchange of thermal energy with the external bath. In this paper we discuss some aspects of the adiabatic freezing of metastable water at constant pressure. In particular, we investigated the thermal behavior of the isobaric gap between the molar volume of supercooled water and that of the warmer ice-water mixture which eventually forms at equilibrium. The available experimental data at ambient pressure, extrapolated into the metastable region within the scheme provided by the reference IAPWS-95 formulation, show that water ordinarily expands upon (partially) freezing under isenthalpic conditions. However, the same scheme also suggests that, for increasing undercoolings, the volume gap is gradually reduced and eventually vanishes at a temperature close to the currently estimated homogeneous ice nucleation temperature. This behavior is contrasted with that of substances which do not display a volumetric anomaly. The effect of increasing pressures on the alleged volume crossover from an expanded to a contracted ice-water mixture is also discussed.

Aliotta, Francesco; Giaquinta, Paolo V.; Pochylski, Mikolaj; Ponterio, Rosina C.; Prestipino, Santi; Saija, Franz; Vasi, Cirino

2013-05-01

191

The Siberian timberman Acanthocinus aedilis : a freeze-tolerant beetle with low supercooling points  

Microsoft Academic Search

Larvae of the Siberian timberman beetle Acanthocinus aedilis display a number of unique features, which may have important implications for the field of cold hardiness in general. Their\\u000a supercooling points are scattered over a wide temperature range, and some individuals have supercooling points in the low\\u000a range of other longhorn beetles. However, they differ from other longhorn beetles in being

E. Kristiansen; N. G. Li; A. I. Averensky; A. E. Laugsand; K. E. Zachariassen

2009-01-01

192

Ponds Freeze in Winter -- Why Doesn't the Ocean?  

NSDL National Science Digital Library

In this activity, learners explore how salt water freezes in comparison to fresh water. Use this experiment to consider how pond animals survive cold winters in comparison to animals that live in the ocean. This resource includes information about freezing points as well as examples of how different animals respond to the winter cold.

Aquarium, New E.

2011-01-01

193

Freezing-memory effect of water on nucleation of CO{sub 2} hydrate crystals  

SciTech Connect

The authors measured the times to nucleate CO{sub 2} hydrates from CO{sub 2} dissolved water under pressure and 8.6 K supercooling using different methods to prepare the water. These times ranged from 50 min to more than 7,200 min, depending on the preparation method. The nucleation rates were calculated by fitting the observed nucleation probability distributions to a nucleation rate equation. The nucleation rates significantly increased when the water had previously frozen as ice and melted (freezing-memory effect), except when the meltwater was heated to 298 K before nucleation. The nucleation rates also increased with O{sub 2}-saturated meltwater, but decreased with degassed water.

Takeya, Satoshi; Hori, Akira; Hondoh, Takeo; Uchida, Tsutomu

2000-05-04

194

Evaluation of the freeze-thaw\\/evaportation process for the treatment of produced waters. Quarterly report, April 1 - June 30, 1996  

Microsoft Academic Search

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural

Boysen

1996-01-01

195

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, April 1, 1994June 30, 1994  

Microsoft Academic Search

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural

J. Boysen; J. Morotti

1994-01-01

196

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, July 1, 1994September 30, 1994  

Microsoft Academic Search

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural

J. Boysen; J. Morotti

1994-01-01

197

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, January 1March 31, 1994  

Microsoft Academic Search

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural

J. Boysen; J. Morotti

1994-01-01

198

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1, 1995December 31, 1995  

Microsoft Academic Search

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural

J. Boysen; J. Morotti

1996-01-01

199

Role of membrane transport of water and glycerol in the freeze tolerance of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)  

Microsoft Academic Search

Overwintering larvae of the rice stem borer, Chilo suppressalis accumulate glycerol and are freezing tolerant to about ?25°C. However, non-diapausing larvae cannot accumulate glycerol and are killed by freezing. We compared the extent of tissue damage, the effects of glycerol concentration, and the transport of glycerol and water in fat body tissues from these larvae at selected freezing temperatures. Tissues

Yohei Izumi; Shoji Sonoda; Hideya Yoshida; Hugh V. Danks; Hisaaki Tsumuki

2006-01-01

200

Effect of Thawing Time, Cooling Rate and Boron Nutrition on Freezing Point of the Primordial Shoot in Norway Spruce Buds  

PubMed Central

• Background Effects of cooling rates on bud frost hardiness have been studied but there is little information on bud responses to thawing. Since the cell wall pore size has been found to increase with boron (B) deficiency, B deficiency may affect the supercooling ability of buds in winter. • Methods The effects of duration of thawing time and rate of cooling on bud frost hardiness of Norway spruce (Picea abies) were studied in a B fertilization trial in February 2003 and March 2005. Frost hardiness of apical buds was determined by differential thermal analysis (DTA) and visual scoring of damage. • Key Results In 2003, the freezing point of primordial shoots of buds (Tf), i.e. the low-temperature exotherm (LTE), was, on average, ?39?°C when buds were thawed for less than 3?h and the Tf increased to ?21?°C after 18?h of thawing. During the first 4?h of thawing, the rate of dehardening was 6?°C h?1. In 2005, buds dehardened linearly from ?39?°C to ?35?°C at a rate of 0·7?°C h?1. In 2003, different cooling rates of 1–5?°C h?1 had a minor effect on Tf but in 2005 with slow cooling rates Tf decreased. In both samplings, at cooling rates of 2 and 1?°C h?1, Tf was slightly higher in B-fertilized than in non-fertilized trees. By contrast, at very short thawing times in 2003, Tf was somewhat lower in B-fertilized trees. • Conclusions There was little evidence of reduced frost hardiness in trees with low B status. This study showed that buds deharden rapidly when exposed to above-freezing temperatures in winter, but if cooled again they reharden more slowly. According to this study, rapid dehardening of buds has to be taken into account in assessments of frost hardiness.

RAISANEN, MIKKO; REPO, TAPANI; LEHTO, TARJA

2006-01-01

201

Experimental and Analytical Investigation of a Freezing Point Depressant Fluid Ice Protection System.  

National Technical Information Service (NTIS)

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 solut...

A. E. Albright

1984-01-01

202

UME Radiation Thermometer Calibration Facilities below the Freezing Point of Silver (961.78 °C)  

NASA Astrophysics Data System (ADS)

Facilities at UME for the calibration of radiation thermometers are described for temperatures generally below 961.78 °C, the lower limit of temperature defined by radiation thermometry on the International Temperature Scale of 1990 (ITS-90). Traceability in the range 200 °C to 1100 °C is obtained using fixed-point blackbody radiators, while traceability from -30 °C to 200 °C is obtained through a homemade variable-temperature blackbody with calibrated 100 ? Pt (Pt100) temperature sensors. The best overall uncertainty for the first range is 0.6 °C, and 0.3 °C for the second range (k=2).

Diril, Ahmet; Nasibov, Humbat; U?ur, Sevilay

2003-09-01

203

The stability against freezing of an internal liquid-water ocean in Callisto.  

PubMed

The discovery of the induced magnetic field of Callisto-one of Jupiter's moons-has been interpreted as evidence for a subsurface ocean, even though the presence of such an ocean is difficult to understand in the context of existing theoretical models. Tidal heating should not be significant for Callisto, and, in the absence of such heating, it is difficult to see how this internal ocean could have survived until today without freezing. Previous work indicated that an outer ice layer on the ocean would be unstable against solid-state convection, which once begun would lead to total freezing of liquid water in about 108 years. Here I show that when a methodology for more physically reasonable water ice viscosities (that is, stress-dependent non-newtonian viscosities, rather than the stress-independent newtonian viscosities considered previously) is adopted, the outer ice shell becomes stable against convection. This implies that a subsurface ocean could have survived up to the present, without the need for invoking antifreeze substances or other special conditions. PMID:11473308

Ruiz, J

2001-07-26

204

Water Relations and Low-Temperature Acclimation for Cactus Species Varying in Freezing Tolerance.  

PubMed Central

Opuntia ficus-indica and Opuntia streptacantha are widely cultivated cacti that can tolerate temperatures no lower than -10[deg]C, whereas Opuntia humifusa, which is native to southern Canada and the eastern United States, can tolerate -24[deg]C. As day/night air temperatures were decreased from 30/20 to 10/0[deg]C, the osmotic pressure increased 0.10 MPa for O. ficus-indica and O. streptacantha but 0.38 MPa for O. humifusa. The increases in osmotic pressures were due mostly to the synthesis of fructose, glucose, and sucrose. In addition, O. humifusa produced a substantial amount of mannitol during exposure to low temperatures. Substantial accumulation of sugars and mannitol in cells of O. humifusa may help prevent intracellular freeze dehydration and ice formation as well as provide noncolligative protection to its membranes. Mucilage was slightly higher in all three species at the lower temperatures. Extracellular nucleation of ice occurred closer to the equilibrium freezing temperature for plants at 10/0[deg]C compared with 30/20[deg]C, which could make the cellular dehydration more gradual and, thus, less damaging. Results from nuclear magnetic resonance indicated a restricted mobility of intracellular water at the lower temperatures, especially for O. humifusa, which is consistent with its lower water content and higher levels of low molecular weight solutes.

Goldstein, G.; Nobel, P. S.

1994-01-01

205

Freezing and Melting  

NSDL National Science Digital Library

This article tells how the freezing point of a substance is also its melting point. The energy of the substance's molecules changes with temperature, thus with changes in state. Also described is how freezing points can be lowered, or depressed, by adding a substance.

2010-01-01

206

Coagulation size of freezable water in poly(vinyl alcohol) hydrogels formed by different freeze\\/thaw cycle periods  

Microsoft Academic Search

The coagulation size of freezable water in a poly(vinyl alcohol) (PVA) hydrogel was investigated as a function of the freeze\\/thaw cycle period using thermal analysis. The melting temperature of ice in the gel shifted to a lower temperature than that of normal ice. This temperature depression can be interpreted in terms of the coagulation size of freezable water in the

Tatsuro Nakano; Takahiko Nakaoki

2011-01-01

207

Field observations of slush ice generated during freeze-up in arctic coastal waters  

USGS Publications Warehouse

In some years, large volumes of slush ice charged with sediment are generated from frazil crystals in the shallow Beaufort Sea during strong storms at the time of freeze-up. Such events terminate the navigation season, and because of accompanying hostile conditions, little is known about the processes acting. The water-saturated slush ice, which may reach a thickness of 4 m, exists for only a few days before freezing from the surface downward arrests further wave motion or pancake ice forms. Movements of small vessels and divers in the slush ice occurs only in phase with passing waves, producing compression and rarefaction, and internal pressure pulses. Where in contact with the seafloor, the agitated slush ice moves cobble-size material, generates large sediment ripples, and may possibly produce a flat rampart observed on the arctic shoreface in some years. Processes charging the slush ice with as much as 1000 m3 km-2 of sediment remain uncertain, but our field observations rule out previously proposed filtration from turbid waters as a likely mechanism. Sedimentary particles apparently are only trapped in the interstices of the slush ice rather than being held by adhesion, since wave-related internal pressure oscillations result in downward particle movement and cleansing of the slush ice. This loss of sediment explains the typical downward increase in sediment concentration in that part of the fast-ice canopy composed largely of frazil ice. The congealing slush ice in coastal water does not become fast ice until grounded ridges are formed in the stamukhi zone, one to two months after freeze-up begins. During this period of new-ice mobility, long-range sediment transport occurs. The sediment load held by the fast-ice canopy in the area between the Colville and Sagavanirktok River deltas in the winter of 1978-1979 was 16 times larger than the yearly river input to the same area. This sediment most likely was rafted from Canada, more than 400 km to the east, during a brief time period in the previous fall. Ocean turbulence is greatly reduced while the congealing slush ice drifts about. Therefore, new ice then forming in intervening open-water areas is clean. These events explain the patchy appearance of the fast ice after the summer snowmelt. More work on the important phenomena reported here is needed to close a major gap in the knowledge of the arctic marine environment. ?? 1987.

Reimnitz, E.; Kempema, E. W.

1987-01-01

208

Activity coefficients and free energies of nonionic mixed surfactant solutions from vapor-pressure and freezing-point osmometry.  

PubMed

The thermodynamic properties of mixed surfactant solutions are widely investigated, prompted by numerous practical applications of these systems and by interest in molecular association and self-organization. General techniques for measuring thermodynamic activities, such as isopiestic equilibration, are well-established for multicomponent solutions. Surprisingly, these techniques have not yet been applied to mixed surfactant solutions, despite the importance of the free energy for micelle stability. In this study, equations are developed for the osmotic coefficients of solutions of nonionic surfactant A + nonionic surfactant B. A mass-action model is used, with virial equations for the activity coefficients of the micelles and free surfactant monomer species. The equations are fitted to osmotic coefficients of aqueous decylsulfobetaine + dodecylsulfobetaine solutions measured by vapor-pressure and freezing-point osmometry. Equilibrium constants for mixed-micelle formation are calculated from the free monomer concentrations at the critical micelle concentrations. The derived activity coefficients of the micelles and free monomers indicate large departures from ideal solution behavior, even for dilute solutions of the surfactants. Stoichiometric activity coefficients of the total surfactant components are evaluated by Gibbs-Duhem integration of the osmotic coefficients. Relatively simple colligative property measurements hold considerable promise for free energy studies of multicomponent surfactant solutions. PMID:21504169

MacNeil, Jennifer A; Ray, Gargi Basu; Leaist, Derek G

2011-04-19

209

Neutron diffraction study of water freezing on aircraft engine combustor soot.  

PubMed

The study of the formation of condensation trails and cirrus clouds on aircraft emitted soot particles is important because of its possible effects on climate. In the present work we studied the freezing of water on aircraft engine combustor (AEC) soot particles under conditions of pressure and temperature similar to the upper troposphere. The microstructure of the AEC soot was found to be heterogeneous containing both primary particles of soot and metallic impurities (Fe, Cu, and Al). We also observed various surface functional groups such as oxygen-containing groups, including sulfate ions, that can act as active sites for water adsorption. Here we studied the formation of ice on the AEC soot particles by using neutron diffraction. We found that for low amount of adsorbed water, cooling even up to 215 K did not lead to the formation of hexagonal ice. Whereas, larger amount of adsorbed water led to the coexistence of liquid water (or amorphous ice) and hexagonal ice (I(h)); 60% of the adsorbed water was in the form of ice I(h) at 255 K. Annealing of the system led to the improvement of the crystal quality of hexagonal ice crystals as demonstrated from neutron diffraction. PMID:21996755

Tishkova, V; Demirdjian, B; Ferry, D; Johnson, M

2011-10-14

210

Conservation of Water-damaged Written Documents by Freeze-drying  

Microsoft Academic Search

ECONOMIC considerations generally eliminate freeze-drying as a practical method for the drying of paper materials. Although we are aware of accounts in the literature about the freeze-drying of paper materials (generally filter paper) we have not seen any references to work on the freeze-drying of written documents for conservation purposes.

James Flink; HENRIK HØYER

1971-01-01

211

Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions  

SciTech Connect

In this program, Rochester Institute of Technology (RIT), General Motors (GM) and Michigan Technological University (MTU) have focused on fundamental studies that address water transport, accumulation and mitigation processes in the gas diffusion layer and flow field channels of the bipolar plate. These studies have been conducted with a particular emphasis on understanding the key transport phenomena which control fuel cell operation under freezing conditions. Technical accomplishments are listed below: • Demonstrated that shutdown air purge is controlled predominantly by the water carrying capacity of the purge stream and the most practical means of reducing the purge time and energy is to reduce the volume of liquid water present in the fuel cell at shutdown. The GDL thermal conductivity has been identified as an important parameter to dictate water accumulation within a GDL. • Found that under the normal shutdown conditions most of the GDL-level water accumulation occurs on the anode side and that the mass transport resistance of the membrane electrode assembly (MEA) thus plays a critically important role in understanding and optimizing purge. • Identified two-phase flow patterns (slug, film and mist flow) in flow field channel, established the features of each pattern, and created a flow pattern map to characterize the two-phase flow in GDL/channel combination. • Implemented changes to the baseline channel surface energy and GDL materials and evaluated their performance with the ex situ multi-channel experiments. It was found that the hydrophilic channel (contact angle ? ? 10?) facilitates the removal of liquid water by capillary effects and by reducing water accumulation at the channel exit. It was also found that GDL without MPL promotes film flow and shifts the slug-to-film flow transition to lower air flow rates, compared with the case of GDL with MPL. • Identified a new mechanism of water transport through GDLs based on Haines jump mechanism. The breakdown and redevelopment of the water paths in GDLs lead to an intermittent water drainage behavior, which is characterized by dynamic capillary pressure and changing of breakthrough location. MPL was found to not only limit the number of water entry locations into the GDL (thus drastically reducing water saturation), but also stabilizes the water paths (or morphology). • Simultaneously visualized the water transport on cathode and anode channels of an operating fuel cell. It was found that under relatively dry hydrogen/air conditions at lower temperatures, the cathode channels display a similar flow pattern map to the ex-situ experiments under similar conditions. Liquid water on the anode side is more likely formed via condensation of water vapor which is transported through the anode GDL. • Investigated the water percolation through the GDL with pseudo-Hele-Shaw experiments and simulated the capillary-driven two-phase flow inside gas diffusion media, with the pore size distributions being modeled by using Weibull distribution functions. The effect of the inclusion of the microporous layer in the fuel cell assembly was explored numerically. • Developed and validated a simple, reliable computational tool for predicting liquid water transport in GDLs. • Developed a new method of determining the pore size distribution in GDL using scanning electron microscope (SEM) image processing, which allows for separate characterization of GDL wetting properties and pore size distribution. • Determined the effect of surface wettability and channel cross section and bend dihedral on liquid holdup in fuel cell flow channels. A major thrust of this research program has been the development of an optimal combination of materials, design features and cell operating conditions that achieve a water management strategy which facilitates fuel cell operation under freezing conditions. Based on our various findings, we have made the final recommendation relative to GDL materials, bipolar design and surface properties, and the combination of materials, design featur

Kandlikar, S.G.; Lu, Z.; Rao, N.; Sergi, J.; Rath, C.; Dade, C.; Trabold, T.; Owejan, J.; Gagliardo, J.; Allen, J.; Yassar, R.S.; Medici, E.; Herescu, A.

2010-05-30

212

Thermocouple observations of melting and freezing plateaus for metal-carbon eutectics between the copper and palladium points  

Microsoft Academic Search

Melting and freezing plateaus were observed with type-R thermocouples for the metal-carbon eutectics Pd-C, Ni-C, and Fe-C. For Pd-C, no apparent difference between the melting and freezing temperatures was observed at a heating\\/cooling rate of 3 °C\\/min. For Ni-C, the difference was 0.4 °C, and for Fe-C, 1.6 °C. The freezing temperature for Fe-C showed dependence on cooling rate, and

Y. Yamada; F. Sakuma; A. Ono

2000-01-01

213

TOPICAL REVIEW: Confinement effects on freezing and melting  

Microsoft Academic Search

A review of experimental work on freezing and melting in confinement is presented. A range of systems, from metal oxide gels to porous glasses to novel nanoporous materials, is discussed. Features such as melting-point depression, hysteresis between freezing and melting, modifications to bulk solid structure and solid-solid transitions are reviewed for substances such as helium, organic fluids, water and metals.

Hugo K. Christenson

2001-01-01

214

Evaluation of the freeze-thaw/evaportation process for the treatment of produced waters. Quarterly report, April 1 - June 30, 1996.  

National Technical Information Service (NTIS)

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. W...

J. Boysen

1996-01-01

215

Use of a droplet nucleation analyzer in the study of water freezing kinetics under the influence of ultrasound waves  

Microsoft Academic Search

In this report we present a new instrument (a droplet nucleation analyzer) to be used in the study of the influence of ultrasonic waves on the freezing of pure water. This influence can be of great interest in the cryopreservation of biological material. Two different types of experiments have been carried out. In the first set of experiments, ultrasound waves

Alberto Olmo; Roberto Baena; Ramon Risco

2008-01-01

216

State of water in extremely halophilic bacteria: Freezing transitions of Halobacterium halobium observed by differential scanning calorimetry  

Microsoft Academic Search

Summary The apparent latent heat of fusion (?H) of thick pastes ofHalobacterium halobium was determined by differential scanning calorimetry and compared with values obtained for a control paste of identical composition but containing bacteria already lysed by freezing and thawing. The rationale of the experiment was that, if there were any physico-chemical “abnormality” in the state of intracellular water or

A. D. Brown; Julian M. Sturtevant

1980-01-01

217

Enhanced Aqueous Dissolution of a Poorly Water Soluble Drug by Novel Particle Engineering Technology: Spray-Freezing into Liquid with Atmospheric Freeze-Drying  

Microsoft Academic Search

Purpose. The purpose of this work was to investigate spray-freezing into liquid (SFL) and atmospheric freeze-drying (ATMFD) as industrial processes for producing micronized SFL powders with enhanced aqueous dissolution. Micronized SFL powders dried by ATMFD were compared with vacuum freeze-dried SFL powders.

True L. Rogers; Andrew C. Nelsen; Marazban Sarkari; Timothy J. Young; Keith P. Johnston; Robert O. Williams

2003-01-01

218

An Investigation of the Cryogenic Freezing of Water in Non-Metallic Pipelines  

NASA Astrophysics Data System (ADS)

Pipe freezing is increasingly used in a range of industries to solve otherwise intractable pipe line maintenance and servicing problems. This paper presents the interim results from an experimental study on deliberate freezing of polymeric pipelines. Previous and contemporary works are reviewed. The object of the current research is to confirm the feasibility of ice plug formation within a polymeric pipe as a method of isolation. Tests have been conducted on a range of polymeric pipes of various sizes. The results reported here all relate to freezing of horizontal pipelines. In each case the process of plug formation was photographed, the frozen plug pressure tested and the pipe inspected for signs of damage resulting from the freeze procedure. The time to freeze was recorded and various temperatures logged. These tests have demonstrated that despite the poor thermal and mechanical properties of the polymers, freezing offers a viable alternative method of isolation in polymeric pipelines.

Martin, C. I.; Richardson, R. N.; Bowen, R. J.

2004-06-01

219

Effect of intercellular junction protein expression on water transport during freezing of MIN6 cells.  

PubMed

A mouse insulinoma (MIN6) strain in which connexin expression has been inhibited by antisense technology holds promise as an experimental model system for investigating the role of gap junctions in intercellular ice propagation. However, to properly interpret measurements of intracellular ice formation kinetics, the effects of cell dehydration on cytoplasmic supercooling must be determined. Thus, the cell membrane water permeability in monolayer cultures of the antisense-transfected MIN6 strain was measured using a fluorescence quenching method. By repeating the experiments at 4°C, 12°C, 21°C, and 37°C, the activation energy for water transport was determined to be E(a) = 51 ± 3 k J/mol. Although differences between membrane permeability measurements in theantisense and wild-type strains were not statistically significant, simulation of water transport during rapid freezing (130°C/min) predicted that intracellular supercooling in the genetically modified MIN6 strain may become significantly larger than the supercooling in wild-type cells at temperatures below -15°C. PMID:23933158

Higgins, Adam Z; Karlsson, Jens O M

2013-08-06

220

The effect of cold acclimation on the water relations and freezing tolerance of Hordeum vulgare L.  

PubMed

During a 5 degree C and a 5/-1 degree C cold acclimation (CA) regime there was a significant decline in the water potential of winter barley, and a concurrent decline in tissue water content of the 5/-1 degree C CA plants. Results of carbohydrate analysis illustrated a significant (P < 0.001) accumulation of sucrose, fructose and glucose in the 5/-1 degree C CA plants, which was inversely correlated to water potential. Using an infrared imaging radiometer during a convection frost test the water release time (WRT) of 5/-1 degree C CA was demonstrated to be significantly (P < 0.001) longer than that observed in non-cold acclimated plants. This observation is consistent with visual analysis of exotherm curves where the rate of cellular water release to extracellular ice is reduced in the 5/-1 degree C CA plants, compared to the non-cold acclimated plants. These biochemical and physiological changes were correlated to increased plant health following a non-lethal freezing test to -5 degree C, where non-cold acclimated plants produced 2.3 +/- 0.3 tillers and 5 degree C and 5/-1 degree C CA plants produced 2.4 +/- 0.3 and 4.7 +/- 0.7 tillers, respectively. Results from this study imply that cold acclimation leads to changes in the physical state of water that result in a less osmotically responsive cellular environment and subsequently significantly less damage to meristematic tissue. PMID:17256061

Burchett, S; Niven, S; Fuller, M P

221

Radiometric observation of melting and freezing plateaus for a series of metal-carbon eutectic points in the range 1330 °C to 1950 °C  

Microsoft Academic Search

Melting and freezing plateaus were radiometrically observed for the metal-carbon eutectics Ni-C, Pd-C, Pt-C, and Ru-C, using graphite crucibles and black-body cavities. The graphite crucibles were able to withstand heat cycles without breaking. Since the crucible material is a component of the eutectic fixed-point material, the latter is inherently free of contamination from the crucible. The temperature differences between the

Y. Yamada; H. Sakate; F. Sakuma; A. Ono

1999-01-01

222

A new optimal control model for reproducing two-point reaching movements of human three-joint arm with wrist joint's freezing mechanism  

Microsoft Academic Search

A new optimal control model of human arms has been developed to simulate two-point reaching movement characteristics for human three-joint arms (shoulder, elbow, and wrist joints) and its fundamental performance has been clarified. The new model is formulated by extending the previous two-joint modified minimum torque-change model to a three-joint model with a freezing mechanism in its wrist joint and

Toshikazu Matsui

2009-01-01

223

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

Microsoft Academic Search

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

2010-01-01

224

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

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.

Stein, C.L.

1985-09-01

225

Water Content during Abscisic Acid Induced Freezing Tolerance in Bromegrass Cells 1  

PubMed Central

Changes in water content and dry weight were determined in control cells and those induced to cold harden in response to abscisic acid (ABA) treatment (7.5 × 10?5 molar). Bromegrass (Bromus inermis Leyss cv Manchar) cells grown in suspension culture at room temperature (23°C) for 7 days acclimated to ?28°C (LT50) when treated with ABA, or to ?5°C when untreated. ABA significantly reduced cell growth rates at 5 and 7 days after treatment. Growth reduction was due to a decrease in cell number rather than cell size. When the cell water content was expressed as percent water (percent H2O) or as grams water per gram dry weight (gram H2O/gram dry weight [g DW]), the water content of hardy, ABA-treated cells decreased from 85% to 77% or from 6.4 to 3.3 g H2O/g DW in 7 days. Control cell water content remained static at approximately 87% and 7.5 g H2O/g DW. However, cell water content, expressed as milligrams water per million cells (milligram H2O/106 cells), did not differ in ABA-treated or control cells. The dry matter content of ABA-treated cells, expressed as milligram DW/106 cells increased to 3.3 milligram/106 cells in 7 days, whereas the dry weight of the control cells remained between 1.4 to 2.1 milligrams/106 cells. The osmotic potential of ABA-treated cells decreased by the fifth day while that of control cells increased significantly and then decreased by day 7. Elevated osmotic potentials were not associated with increased ion uptake. In contrast to much published literature, these results suggest that cell water content does not decrease in ABA-treated cells during the induction of freezing tolerance, rather the dry matter mass per cell increased. Cell water content may be more accurately expressed as a function of cell number when accompanying changes to dry cell matter occur.

Tanino, Karen; Weiser, Conrad J.; Fuchigami, Leslie H.; Chen, Tony H. H.

1990-01-01

226

Poromechanics of freezing materials  

NASA Astrophysics Data System (ADS)

When subjected to a uniform cooling below the freezing point a water-infiltrated porous material undergoes a cryo-deformation resulting from various combined actions: (i) the difference of density between the liquid water and the ice crystal, which results in the initial build-up of an in-pore pressure at the onset of crystallization; (ii) the interfacial effects arising between the different constituents, which eventually govern the crystallization process in connection with the pore access radius distribution; (iii) the drainage of the liquid water expelled from the freezing sites towards the air voids; (iv) the cryo-suction process, which drives liquid water towards the already frozen pores as the temperature further decreases; (v) the thermomechanical coupling between the solid matrix, the liquid water and the ice crystal. We work out a comprehensive theory able to encompass this whole set of actions. A macroscopic approach first provides the constitutive equations of freezing poroelastic materials, including the interfacial energy effects. This approach reveals the existence of a thermodynamic state function—namely the liquid saturation degree as a function of the temperature only. The macroscopic ice-dependent poroelastic properties are then upscaled from the knowledge of the elastic properties of the solid matrix, of the pore access radius distribution, and of the capillary curve. The theory is finally illustrated by analysing quantitatively the effects of the cooling rate and of the pore radius distribution upon the cryo-deformation of water-infiltrated porous materials. The theory succeeds in accounting for the experimentally observed shrinkage of embedded air voids, while predicting the partial melting of the ice already formed when the cooling suddenly stops.

Coussy, Olivier

2005-08-01

227

Freezing of water inside model carbon nanotubes and graphitic slit pores  

NASA Astrophysics Data System (ADS)

Phase behavior of water confined to model carbon nanotubes was studied by means of molecular dynamics simulation. In quasi-one-dimensional carbon nanobutes, it is found that the polymorphic phase transition is very sensitive to the diameter of the model nanotubes. The simulation suggests that upon cooling, a first-order freezing-like transition to hexagon and heptagon ice nanotubes, or a continuous phase transformation into solid-like square or pentagon ice nanotubes can occur, depending upon the diameter (1.1 - 1.4 nm) of the model nanotubes. Ab initio plane-wave pseudopotential calculation was carried out to investigate relative stability of the pentagon and hexagon ice nanotubes. Electronic structure calculations indicate that ice nanotubes exhibit nearly the same band structures and bandgap as those of proton-ordered bulk ice I_h. In quasi-two-dimensional model graphitic slits, both polymorphic and polyamorphic phase transitions were observed. The latter transition arises when the water is supercooled and confined to the slit nanopore with a fixed width, in which crystallization to the two-dimensional bilayer ice is generally inhibited.

Zeng, Xiao-Cheng

2003-03-01

228

Effect of temperature of CO2 injection on the pH and freezing point of milks and creams.  

PubMed

The objectives of this study were to measure the impact of CO2 injection temperature (0 degree C and 40 degrees C) on the pH and freezing point (FP) of (a) milks with different fat contents (i.e., 0, 15, 30%) and (b) creams with 15% fat but different fat characteristics. Skim milk and unhomogenized creams containing 15 and 30% fat were prepared from the same batch of whole milk and were carbonated at 0 and 40 degrees C in a continuous flow CO2 injection unit (230 ml/min). At 0 degree C, milk fat was mostly solid; at 40 degrees C, milk fat was liquid. At the same total CO2 concentration with CO2 injection at 0 degree C, milk with a higher fat content had a lower pH and FP, while with CO2 injection at 40 degrees C, milks with 0%, 15%, and 30% fat had the same pH. This indicated that less CO2 was dissolved in the fat portion of the milk when the CO2 was injected at 0 degree C than when it was injected at 40 degrees C. Three creams, 15% unhomogenized cream, 15% butter oil emulsion in skim milk, and 15% vegetable oil emulsion in skim milk were also carbonated and analyzed as described above. Vegetable oil was liquid at both 0 and 40 degrees C. At a CO2 injection temperature of 0 degree C, the 15% vegetable oil emulsion had a slightly higher pH than the 15% butter oil emulsion and the 15% unhomogenized cream, indicating that the liquid vegetable oil dissolved more CO2 than the mostly solid milk fat and butter oil. No difference in the pH or FP of the 15% unhomogenized cream and 15% butter oil emulsion was observed when CO2 was injected at 0 degree C, suggesting that homogenization or physical dispersion of milk fat globules did not influence the amount of CO2 dissolved in milk fat at a CO2 injection temperature of 0 degree C. At a CO2 injection temperature of 40 degrees C and at the same total CO2 concentration, the 15% unhomogenized cream, 15% vegetable oil emulsion, and 15% butter oil emulsion had similar pH. At the same total concentration of CO2 in cream, injection of CO2 at low temperature (i.e., < 4 degrees C) may produce a better antimicrobial effect during refrigerated shelf life due to the higher concentration of CO2 in the skim portion of the cream. PMID:12778568

Ma, Y; Barbano, D M

2003-05-01

229

SOLERAS - Solar-Powered Water Desalination Project at Yanbu: Indirect freeze desalination system performance  

SciTech Connect

The desalination subsystem of the solar-powered desalination pilot project located at Yanbu, Saudi Arabia, was operated successfully for two years. Water production rates of 180 m/sup 3//day can be obtained for a period of 24 hours. In addition, once the proper procedures are followed, water production can continue for long periods of time at rates of 135 m/sup 3//day. Electrical energy costs to produce one m/sup 3/ of potable water is SR 1.66 in Saudi Arabia and $1.66 to $2.21 in the United States. As with any new process, a number of important details must be learned to obtain the most out of the system. Some of these details are: (1) product water production rate and efficiency are maximized for this system at 10% salinity and ..delta..Ts greater than 3/degree/C, (2) the anhydrous ammonia must be kept clean, (3) the ice in the freezer tubes must be melted without decreasing the salinity of the mixture in the slurry separator, (4) the salinity of the mixture going through each of the freezer tubes must be the same, and (5) the salinity of the slurry must be less than 11%. The authors believe that a subsequent design of an indirect-contact freeze desalination sub-system can be successful. Maintenance of the desalination subsystem has been nominal with only about 6/1/2/ person days required per month. Proper operating procedures and some redesign of the desalination subsystem should minimize the required maintenance. 4 refs., 7 figs., 4 tabs.

Zimmerman, J.C.; Al-Abbadi, N.

1987-05-01

230

Freezing avoidance of the Antarctic icefishes (Channichthyidae) across thermal gradients in the Southern Ocean  

Microsoft Academic Search

Biogeographic studies separate the Antarctic Notothenioid fish fauna into high- and low-latitude species. Past studies indicate\\u000a that some species found in the high-latitude freezing waters of the High-Antarctic Zone have low-serum hysteresis freezing\\u000a points, while other species restricted to the low-latitude seasonal pack ice zone have higher serum hysteresis freezing points\\u000a above the freezing point of seawater (?1.9°C), but the

Kevin T. Bilyk; Arthur L. DeVries

2010-01-01

231

Passive freeze protection for solar collectors  

Microsoft Academic Search

Freeze damage is an important practical problem for water-type solar collectors. This note describes a simple passive concept that can be used to protect water-type solar collectors from freeze damage. Briefly, the water is allowed to freeze. As it freezes, however, it expands against a compliant region, and thus, the expansion does not damage the system. (auth)

L BICKLE

1975-01-01

232

Osmotic Coefficients of Aqueous Solutions of Some Poly(oxyethylene) Glycols at the Freezing Point of Solution  

Microsoft Academic Search

Summary. The freezing temperatures of dilute aqueous solutions of some poly(oxyethylene) glycols ( PEG, HO–(CH 2CH 2O) n–H, n varying from 4 to 117) were measured over a solute to solvent mass ratio from 0.0100 to 0.3900. The second and third osmotic virial coefficient ( A 22 and A 222) of poly(oxyethylene) glycols in aqueous solution were determined. The molecular

Darja Rudan-Tasic; Cveto Klofutar

2004-01-01

233

40 CFR 142.57 - Bottled water, point-of-use, and point-of-entry devices.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Bottled water, point-of-use, and point-of-entry...the Administrator § 142.57 Bottled water, point-of-use, and point-of-entry...require a public water system to use bottled water, point-of-use...

2010-07-01

234

40 CFR 142.57 - Bottled water, point-of-use, and point-of-entry devices.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Bottled water, point-of-use, and point-of-entry...the Administrator § 142.57 Bottled water, point-of-use, and point-of-entry...require a public water system to use bottled water, point-of-use...

2013-07-01

235

Evaluation of the MilkoScan FT 6000 milk analyzer for determining the freezing point of goat's milk under different analytical conditions.  

PubMed

The aim of this research was to evaluate the Milko-Scan FT 6000 (Foss Electric, Hillerød, Denmark) for determining the freezing point (FP) of goat's milk under different analytical conditions. The FP was determined in duplicate in 1,800 milk aliquots obtained from 45 bulk tank milk samples from 10 Murciano-Granadina goat herds, using the MilkoScan method and a reference thermistor cryoscopy method (Advanced Instrument Inc., Norwood, MA). Five different preservation strategies--no preservative, preservation with azidiol (0.006 or 0.018 g of sodium azide/100 mL), and preservation with bronopol (0.020 or 0.040 g/100 mL)--were then used to preserve the milk. For each preservation strategy, 8 different amounts of water were added (0, 1, 2, 3, 4, 5, 6, or 7% total volume). The results obtained with each method under these 40 analytical conditions were examined by comparison of means, comparison of the standard deviations of repeatability (s(r) and its relative value s(r)%), and a regression analysis. Under most analytical conditions, the FP was recorded as lower by the MilkoScan method, with a mean difference of 1.5 m degrees C compared with the reference method. Both methods showed similar repeatabilities (the overall s(r)% was 0.22% for the MilkoScan method and 0.20% for the reference method). In comparisons of the 2 methods, the highest regression coefficients were obtained with aliquots containing >3% added water. The best regression coefficients (0.85 to 1.02) were obtained for milk samples preserved with bronopol at 0.020 g/100 mL. These results allow the MilkoScan method to be used with goat's milk for screening purposes. The factors of added water, preservative, analytical method, lactose concentration, and the effect of the bulk tank milk sample within each lactose group contributed significantly to the observed variation in FP. For practical purposes, either of the bronopol concentrations could be used when determining the FP of goat's milk with the methods tested. However, the increase in the concentration of sodium azide in the azidiol formula contributed to an important reduction in the FP recorded. Thus, the type and concentration of preservative should be taken into account when interpreting FP values. PMID:17582097

Sánchez, A; Sierra, D; Luengo, C; Corrales, J C; de la Fe, C; Morales, C T; Contreras, A; Gonzalo, C

2007-07-01

236

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: A molecular dynamics simulation study  

NASA Astrophysics Data System (ADS)

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?*=1, 2, 3 is 0.656 +/- 0.001, 0.726 +/- 0.002, and 0.835 +/- 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed 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, i.e., ?100 > ?110 > ?111.

Wang, Jun; Apte, Pankaj A.; Morris, James R.; Zeng, Xiao Cheng

2013-09-01

237

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: A molecular dynamics simulation study.  

PubMed

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?(*)=1,?2,?3 is 0.656 ± 0.001, 0.726 ± 0.002, and 0.835 ± 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed 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, i.e., ?100 > ?110 > ?111. PMID:24070303

Wang, Jun; Apte, Pankaj A; Morris, James R; Zeng, Xiao Cheng

2013-09-21

238

Role of membrane transport of water and glycerol in the freeze tolerance of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae).  

PubMed

Overwintering larvae of the rice stem borer, Chilo suppressalis accumulate glycerol and are freezing tolerant to about -25 degrees C. However, non-diapausing larvae cannot accumulate glycerol and are killed by freezing. We compared the extent of tissue damage, the effects of glycerol concentration, and the transport of glycerol and water in fat body tissues from these larvae at selected freezing temperatures. Tissues from overwintering larvae, but not non-diapausing larvae, survive when frozen at -20 degrees C with 0.25 M glycerol, but the protection afforded by glycerol is offset by the water-channel inhibitor mercuric chloride. Glycerol in higher concentration (0.75 M) affords some protection even to the fat body of non-diapausing larvae. Radiotracer assays of overwintering larvae show that water leaves the tissues during freezing while glycerol enters, and that mercuric chloride disrupts this process. Transport is also disrupted after lethal freezing at -35 degrees C. Therefore, membrane transport of water and glycerol is involved in the avoidance of freezing injury to fat body cells of the rice stem borer, apparently by mediating the replacement of water with glycerol in freezing-tolerant tissues. PMID:16359699

Izumi, Yohei; Sonoda, Shoji; Yoshida, Hideya; Danks, Hugh V; Tsumuki, Hisaaki

2005-12-15

239

Effects of water immersion-freeze-thaw cycling on the properties of wood-polypropylene composites containing pigments  

Microsoft Academic Search

Purpose – The purpose of this paper is to study the effects of water immersion-freeze-thaw treatment on the physical properties, flexural strength (FS) and morphology of wood-polypropylene composites containing pigments. Design\\/methodology\\/approach – Wood-polypropylene composites containing brown, green and grey pigments were compounded in a conical twin-screw extruder. A composite manufactured without any pigment addition was used as a reference. The

Svetlana Butylina; Ossi Martikka; Timo Kärki

2011-01-01

240

Chilling and freezing of part-baked bread. Part II: Experimental assessment of water phase changes and structure collapse  

Microsoft Academic Search

The first objective of the present work was to assess physical changes taking place during the pre-chilling and freezing of part-baked bread, by means of MRI. The second objective was to relate them to the appearance of crust flakes in certain circumstances after final baking at retail.The intensity of the MRI signal decreased in all voxels once water crystallization started.

T. Lucas; S. Quellec; A. Le Bail; A. Davenel

2005-01-01

241

The effects of water deprivation on conditioned freezing to contextual cues and to a tone in rats  

Microsoft Academic Search

In two experiments we used an automated system for quantifying freezing responses in rats to replicate and extend Maren et al. (Maren S, DeCola JP, Fanselow MS. Water deprivation enhances fear conditioning to contextual, but not discrete, conditional stimuli in rats. Behav Neurosci 1994;108:645–9; Maren S, DeCola JP, Swain RA, Fanselow MS, Thompson RF. Parallel augmentation of hippocampal long-term potentiation,

Bruno Pouzet; Wei-Ning Zhang; Mark A Richmond; J. Nicholas P Rawlins; Joram Feldon

2001-01-01

242

Visualization of the freeze\\/thaw characteristics of a copper\\/water heat pipe - Effects of non-condensible gas  

Microsoft Academic Search

The freeze\\/thaw characteristics of a copper\\/water heat pipe of rectangular cross section were investigated experimentally to determine the effect of variations in the amount of non-condensible gases (NCG) present. The transient internal temperature profiles in both the liquid and vapor channels are presented along with contours of the frozen fluid configuration obtained through visual observation. Several interesting phenomena were observed

J. M. Ochterbeck; G. P. Peterson

1991-01-01

243

Real-time Non-contact Millimeter Wave Characterization of Water-Freezing and Ice-Melting Dynamics  

SciTech Connect

We applied millimeter wave radiometry for the first time to monitor water-freezing and ice-melting dynamics in real-time non-contact. The measurements were completed at a frequency of 137 GHz. Small amounts (about 2 mL) of freshwater or saltwater were frozen over a Peltier cooler and the freezing and melting sequence was recorded. Saltwater was prepared in the laboratory that contained 3.5% of table salt to simulate the ocean water. The dynamics of freezing-melting was observed by measuring the millimeter wave temperature as well as the changes in the ice or water surface reflectivity and position. This was repeated using large amounts of freshwater and saltwater (800 mL) mimicking glaciers. Millimeter wave surface level fluctuations indicated as the top surface melted, the light ice below floated up indicating lower surface temperature until the ice completely melted. Our results are useful for remote sensing and tracking temperature for potentially large-scale environmental applications, e.g., global warming.

Sundaram, S. K.; Woskov, Paul P.

2008-11-12

244

The Freezing Bomb  

ERIC Educational Resources Information Center

|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.…

Mills, Allan

2010-01-01

245

Final Report on the Investigation of Water Purification and Waste Concentration by the Vacuum Freezing Multiple Phase Transformation Process and Its Eutectic Extension, September 1986-September 1987.  

National Technical Information Service (NTIS)

The study is a continuation of the study of the Volume Freezing Multiple Phase Transformation (VFMPT) process for desalination and water reuse. During the first grant period, bench scale experiments were completed for the VFMPT process and initial design ...

C. Y. Cheng W. C. Cheng

1988-01-01

246

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

PubMed

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

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

2013-04-10

247

Immersion freezing of water and aqueous ammonium sulfate droplets initiated by humic-like substances as a function of water activity  

NASA Astrophysics Data System (ADS)

Immersion freezing of water and aqueous (NH4)2SO4 droplets containing leonardite (LEO) and Pahokee peat (PP) serving as surrogates for humic-like substances (HULIS) has been investigated. Organic aerosol containing HULIS are ubiquitous in the atmosphere; however, their potential for ice cloud formation is uncertain. Immersion freezing has been studied for temperatures as low as 215 K and solution water activity, aw, from 0.85 to 1.0. The freezing temperatures of water and aqueous solution droplets containing LEO and PP are 5-15 K warmer than homogeneous ice nucleation temperatures. Heterogeneous freezing temperatures can be represented by a horizontal shift of the ice melting curve as a function of solution aw by ?aw = 0.2703 and 0.2466, respectively. Corresponding hetrogeneous ice nucleation rate coefficients, Jhet, are (9.6 ± 2.5)×104 and (5.4 ± 1.4)×104 cm-2 s-1 for LEO and PP containing droplets, respectively, and remain constant along freezing curves characterized by ?aw. Consequently predictions of freezing temperatures and kinetics can be made without knowledge of the solute type when relative humidity and ice nuclei (IN) surface areas are known. The acquired ice nucleation data are applied to evaluate different approaches to fit and reproduce experimentally derived frozen fractions. In addition, we apply a basic formulation of classical nucleation theory (?(T)-model) to calculate contact angles and frozen fractions. Contact angles calculated for each ice nucleus as a function of temperature, ?(T)-model, reproduce exactly experimentally derived frozen fractions without involving free-fit parameters. However, assigning the IN a single contact angle for the entire population (single-? model) is not suited to represent the frozen fractions. Application of ?-PDF, active sites, and deterministic model approaches to measured frozen fractions yield similar good representations. Furthermore, when using a single parameterization of ?-PDF or active sites distribution to fit all individual aw immersion freezing data simultaneously, frozen fraction curves are not reproduced. This implies that these fitting formulations cannot be applied to immersion freezing of aqueous solutions, and suggests that derived fit parameters do not represent independent particle properties. Thus, from fitting frozen fractions only, the underlying ice nucleation mechanism and nature of the ice nucleating sites cannot be inferred. In contrast to using fitted functions obtained to represent experimental conditions only, we suggest to use experimentally derived Jhet as a function of temperature and aw that can be applied to conditions outside of those probed in laboratory. This is because Jhet(T) is independent of time and IN surface areas in contrast to the fit parameters obtained by representation of experimentally derived frozen fractions.

Rigg, Y. J.; Alpert, P. A.; Knopf, D. A.

2013-07-01

248

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996  

SciTech Connect

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil and gas producing regions of Wyoming, are well suited for application of these processes in combination. Specifically, the objectives of this research are related to the development of a commercially-economic FTE (freeze-thaw/evaporation) process for the treatment and purification of water produced in conjunction with oil and natural gas. The research required for development of this process consists of three tasks: (1) a literature survey and process modeling and economic analysis; (2) laboratory-scale process evaluation; and (3) field demonstration of the process. Results of research conducted for the completion of these three tasks indicate that produced water treatment and disposal costs for commercial application of the process, would be in the range of $0.20 to $0.30/bbl in the Rocky Mountain region. FTE field demonstration results from northwestern New Mexico during the winter of 1995--96 indicate significant and simultaneous removal of salts, metals, and organics from produced water. Despite the unusually warm winter, process yields demonstrate disposal volume reductions on the order of 80% and confirm the potential for economic production of water suitable for various beneficial uses. The total dissolved solids concentrations of the FTE demonstration streams were 11,600 mg/L (feed), 56,900 mg/L (brine), and 940 mg/L (ice melt).

Boysen, J.E.; Walker, K.L.; Mefford, J.L.; Kirsch, J.R. [Resource Technology Corp., Laramie, WY (United States); Harju, J.A. [North Dakota Univ., Grand Forks, ND (United States). Energy and Environmental Research Center

1996-06-01

249

Cell Freeze Liquid Nitrogen Freezing Container  

Center for Biologics Evaluation and Research (CBER)

... Cell Freeze Liquid Nitrogen Freezing Container. Applicant: Charter Medical, Ltd. ... Product: Cell Freeze Liquid Nitrogen Freezing Container. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

250

Sub-cooled water detection in silicon dew point hygrometer  

Microsoft Academic Search

A new type of silicon dew point detector is presented in this paper. The fabricated detector structures contain a thermometer, two heaters, a capacitive interdigitated sensor for the detection of water, sub-cooled water, as well as ice. The test results of sub-cooled water recognition are carefully described. The theoretical model of the capacitive interdigitated sensor describing the principle of detection

R Jachowicz; J Weremczuk

2000-01-01

251

State diagram and water adsorption isotherm of raspberry ( Rubus idaeus)  

Microsoft Academic Search

Thermal transitions of freeze-dried raspberry powder (Rubus idaeus) were analyzed by using differential scanning calorimetry. Freeze-dried raspberry powders containing unfreezable and freezable water were examined to develop the state diagram of raspberry. The state diagram of freeze-dried raspberry powders included the glass line; glass transition temperature versus solids content, freezing curve; initial freezing point versus solids content; end point of

Roopesh M. Syamaladevi; Shyam S. Sablani; Juming Tang; Joseph Powers; Barry G. Swanson

2009-01-01

252

Effect of glycerol and cholesterol-loaded cyclodextrin on freezing-induced water loss in bovine spermatozoa.  

PubMed

Recent experimental data show that incubating bovine sperm with cholesterol-loaded cyclodextrin (CLC) before cryopreservation increases the percentages of motile and viable cells recovered after freezing and thawing, compared with control sperm. In the present study, we report the effect of incubating bovine sperm with CLC on the subzero water transport response and the membrane permeability parameters (reference membrane permeability (L(pg)) and activation energy (E(Lp))). Water transport data during freezing of bovine sperm cell suspensions were obtained at a cooling rate of 20 degrees C/min under three different conditions: 1. in the absence of cryoprotective agents (CPAs); 2. in the presence of 0.7 M glycerol; and 3. in the presence of 1.5 mg/ml CLC and 0.7 M glycerol. With previously published values, the bovine sperm cell was modeled as a cylinder of length 39.8 microm and radius 0.4 microm, with osmotically inactive cell volume (V(b)) of 0.61 V(o), where V(o) is the isotonic cell volume. By fitting a model of water transport to the experimentally obtained data, the best-fit water transport parameters (L(pg) and E(Lp)) were determined. The predicted best-fit permeability parameters ranged from L(pg) = 0.02 to 0.036 microm/min-atm and E(Lp) = 26.4 to 42.1 kcal/mol. These subzero water transport parameters are significantly different from the suprazero membrane permeability values (obtained in the absence of extracellular ice) reported in the literature. Calculations made of the theoretical response of bovine spermatozoa at subzero temperatures suggest that the optimal cooling rate to cryopreserve bovine spermatozoa is 45-60 degrees C/min, agreeing quite closely with experimentally determined rates of freezing bovine spermatozoa. PMID:16672352

Li, G; Saenz, J; Godke, R A; Devireddy, R V

2006-05-01

253

Comp aratrve Ultrastructure of Fat Body Cells of Freeze-susceptible and Freeze-tolerant Eurosta solidaginis Larvae After Chemical Fixation and High Pressure Freezing  

Microsoft Academic Search

Cold-hard- ening includes the elevation of the supercooling point, the temperature at which body water spontaneously freezes, and the accumulation of the low-molecular-mass cryoprotectants, glycerol, sorbitol and trehalose. Although it is generally believed that freezing survival is only possible if the ice lattice is restricted to the extracellular space, the larval fat body cells survive intracellular ice formation. Fat body

R. TODD MORASON; ALLAN L. ALLENSPACH; RICHARD E. LEE JR

254

Freezing Precipitation.  

National Technical Information Service (NTIS)

This technical note discusses three advection patterns favorable for freezing precipitation. Two graphs were developed based on 503 freezing precipitation occurrences during the past 11 years- a 1000- to 500-mb thickness graph and an 850-mb temperature gr...

E. M. Weber

1998-01-01

255

Hatchling turtles survive freezing during winter hibernation.  

PubMed Central

Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. Turtles survived frequent exposures to temperatures as low as -6 degrees C to -8 degrees C in their shallow terrestrial nests over the 1987-1988 winter. Hatchlings collected in April 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees C and survived 24 hr of freezing at -4 degrees C with 53.4% +/- 1.98% of total body water as ice. Recovery appeared complete after 20 hr of thawing at 3 degrees C. However, freezing at -10.9 degrees C, resulting in 67% ice, was lethal. A survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3-fold increase in blood glycerol in response to freezing. Although quantitatively low, these responses by spring turtles strongly indicate that these may be the winter-active cryoprotectants. The total amino acid pool of blood also increased 2.25-fold in freezing-exposed turtles, and taurine accounted for 52% of the increase. Most organs accumulated high concentrations of lactate during freezing, a response to the ischemic state imposed by extracellular freezing. Changes in glycogen phosphorylase activity and levels of glucose 6-phosphate and fructose 2,6-bisphosphate were also consistent with a dependence on anaerobic glycolysis during freezing. Studies of the molecular mechanisms of natural freeze tolerance in these turtles may identify protective strategies that can be used in mammalian organ cryopreservation technology.

Storey, K B; Storey, J M; Brooks, S P; Churchill, T A; Brooks, R J

1988-01-01

256

Eutectic freeze crystallization: Application to process streams and waste water purification  

Microsoft Academic Search

Two case studies are presented using eutectic freeze crystallization (EFC) as an alternative for evaporative crystallization: a 7.8 ton day?1 35 w% aqueous sodium nitrate and a 24 ton day?1 12 w% copper sulfate stream. The proposed crystallizer is a cooled disk column crystallizer (CDCC), using indirect cooling for heat transfer. In single stage operation, the formed ice crystals are

F. van der Ham; G. J. Witkamp; J. de Graauw; G. M. van Rosmalen

1998-01-01

257

Effect of Pore Water Freezing on the Strength of Pierre Shale.  

National Technical Information Service (NTIS)

Triaxial compression tests were performed on Pierre shale to determine the effect of freezing on the strength of saturated rock. Triaxial tests were conducted at pressure up to 70 ksi and temperatures of 10F. A significant strengthening effect was seen wh...

S. R. Swanson W. S. Brown

1974-01-01

258

Second Inflection Point of the Surface Tension of Water  

NASA Astrophysics Data System (ADS)

The theme of a second inflection point of the temperature dependence of the surface tension of water remains a subject of controversy. Using data above 273 K, it is difficult to get a proof of existence of the second inflection point, because of experimental uncertainties. Data for the surface tension of supercooled water and results of a molecular dynamics study were included into the exploration of existence of an inflection point. A new term was included into the IAPWS equation to describe the surface tension in the supercooled water region. The new equation describes the surface tension values of ordinary water between 228 K and 647 K and leads to the inflection point value at a temperature of about 1.5 °C.

Kalova, Jana; Mares, Radim

2012-06-01

259

The influence of van der Waals forces on the state of water in the shallow subsurface of Mars  

Microsoft Academic Search

Microscopic liquid layers of water can evolve via adsorption on grain and mineral surfaces at and in the soil of the surface of Mars. The upper parts of these layers will start to freeze at temperatures clearly below the freezing point of bulk water (freezing point depression). A sandwich structure with layers of ice (top), liquid water (in between) and

Diedrich T. F. Möhlmann

2008-01-01

260

The influence of van der Waals forces on the state of water in the shallow subsurface of Mars  

Microsoft Academic Search

Microscopic liquid layers of water can evolve via adsorption on grain and mineral surfaces at and in the soil of the surface of Mars. The upper parts of these layers will start to freeze at temperatures clearly below the freezing point of bulk water (freezing point depression). A sandwich structure with layers of ice (top), liquid water (in between) and

Diedrich T. F. Möhlmann

261

FREEZE-THAWING EFFECTS ON PHOSPHORUS LOSS IN RUNOFF FROM MANURED AND CATCH-CROPPED SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Concern over non-point source phosphorus (P) losses from agricultural lands to surface waters in frigid climates has focused interest on the effects of freezing and thawing on P loss in overland and subsurface flow. This study evaluated the effect of freezing and thawing on the fate of P in bare soi...

262

Partial removal of water before freezing: cultivar and pre-treatments as quality factors of frozen muskmelon ( Cucumis melo, cv reticulatus Naud.)  

Microsoft Academic Search

The influence of both the cultivar and the dehydration method, applied before freezing, on quality characteristics of dehydrofrozen muskmelon spheres has been studied. Water was removed from muskmelon cultivar Mirado and Rony, prior to freezing, by Dewatering–Impregnation–Soaking in concentrated solution (DIS) for 1 h, air dehydration and combined DIS-air dehydration to a final 50% weight reduction. The results of the

Andrea Maestrelli; Roberto Lo Scalzo; Daniela Lupi; Gianni Bertolo; Danila Torreggiani

2001-01-01

263

Isotopic composition of water used for triple point of water cells  

Microsoft Academic Search

Measurements of the isotopic composition of water used in the production of triple point of water cells show that state-of-the-art triple point realizations must consider corrections and uncertainties due to variations in the isotopic composition of water. Triple point cell production processes yield cells with triple point temperatures 60 µK below that implied by the definition, with a similar sized

J. V. Nicholas; T. D. Dransfield; D. R. White

1996-01-01

264

The Effect of Water Soluble Substances on the Supercooling of Water Drops  

Microsoft Academic Search

While the temperature at which ice is in equilibrium with a solution (equilibrium freezing point of the solution) is invariably lower than the corresponding value for pure water, in actual experiments in which the temperature of a sample of solution is reduced until freezing starts (non-equilibrium freezing point of the solution) the supercooling is frequently less than that for pure

Hans R. Pruppacher; M. Neiburger

1963-01-01

265

Improved Estimates of the Isotopic Correction Constants for the Triple Point of Water  

NASA Astrophysics Data System (ADS)

In 2006, the CIPM clarified the definition of the kelvin by specifying the isotopic composition of the water to be used in the realization of the triple point. At the same time, the Consultative Committee for Thermometry gave recommended values for the isotopic correction constants to be used for water departing from the specified composition. However, the uncertainties in the values for the correction constants were undesirably large due to unresolved differences between the data sets from which the values were determined. This paper derives improved values of the constants by considering additional data from isotopic fractionation measurements and the heats of fusion and freezing points of the relevant water isotopologues. Values of the corrections determined from the expanded data are A D = 671(10) ?K, A 18O = 603(3) ?K, and A 17O = 60(1) ?K. A typical correction made with these values lies just within the expanded uncertainty ( k = 2) of the corrections made with the older values, but has about half the uncertainty.

White, D. R.; Tew, W. L.

2010-09-01

266

Cell Size and Water Permeability as Determining Factors for Cell Viability after Freezing at Different Cooling Rates  

PubMed Central

This work studied the viabilities of five types of cells (two yeast cells, Saccharomyces cerevisiae CBS 1171 and Candida utilis; two bacterial strains, Escherichia coli and Lactobacillus plantarum; and one human leukemia K562 cell) as a function of cooling rate during freezing. The range of investigated cooling rates extended from 5 to 30,000°C/min. Cell viability was classified into three ranges: (i) high viability for low cooling rates (5 to 180°C/min), which allow cell water outflow to occur completely and do not allow any intracellular crystallization; (ii) low viability for rapid cooling rates (180 to 5,000°C/min), which allow the heat flow to prevail over water outflow (in this case, cell water crystallization would occur as water was flowing out of the cell); (iii) high viability for very high cooling rates (>5,000°C/min), which allow the heat flow to be very rapid and induce intracellular crystallization and/or vitrification before any water outflow from the cell. Finally, an assumption relating cell death to the cell water crystallization as water is flowing out of the cell is made. In addition, this general cell behavior is different for each type of cell and seems to be moderated by the cell size, the water permeability properties, and the presence of a cell wall.

Dumont, Frederic; Marechal, Pierre-Andre; Gervais, Patrick

2004-01-01

267

Spray freezing into liquid (SFL) particle engineering technology to enhance dissolution of poorly water soluble drugs: organic solvent versus organic\\/aqueous co-solvent systems  

Microsoft Academic Search

A spray freezing into liquid (SFL) particle engineering technology has been developed to produce micronized powders to enhance the dissolution of poorly water soluble active pharmaceutical ingredients (APIs). Previously, a tetrahydrofuran (THF)\\/water co-solvent was used as the solution source in the SFL process. In the present study, an organic system was developed to further enhance the properties of particles produced

Jiahui Hu; Keith P. Johnston; Robert O. Williams

2003-01-01

268

a Laboratory Investigation of Droplet Freezing  

Microsoft Academic Search

Laboratory experimentation was undertaken to investigate the effects of various soluble and insoluble nuclei on the freezing temperature of water droplets. The freezing temperature and size of over 15,000 droplets were obtained. Pure water was produced, and subsequently frozen in droplet form. The freezing temperatures of various sizes of pure water droplets were used as a reference standard for the

Thomas E. Hoffer

1961-01-01

269

Freezing Resistance in Some Antarctic Fishes  

Microsoft Academic Search

Measurements of serum freezing points in three Antarctic marine fishes indicated that they do not freeze in the -1.87 degrees C seawater because their blood is isosmotic to seawater. Concentrations of sodium chloride, urea, and free amino acids in the serum accounted for only half of the freezing-point depression of the serum. A protein containing carbohydrate was isolated which accounted

Arthur L. Devries; Donald E. Wohlschlag

1969-01-01

270

Non-equilibrium freezing of water-ice in sandy basaltic regoliths and implications for fluidized debris flows on Mars  

NASA Astrophysics Data System (ADS)

Many geomorphic features on Mars were attributed to Earth-analogous, cold-climate processes involving movement of water or ice lubricated debris. Clearly, knowledge of the behavior of water in regolith materials under Martian conditions is essential to understanding the postulated geomorphic processes. Experiments were performed with sand-sized samples of natural basaltic regoliths in order to further elucidate how water/regolith interactions depend upon grain size and mineralogy. The data reveal important contrasts with data for clay-mineral substrates and suggest that the microphysics of water/mineral interactions might affect Martian geomorphic processes in ways that are not fully appreciated. Sand and silt sized fractions of two soils from the summit of Mauna Kea were used as Mars-analogous regolith materials. Temperatures were measured for water/ice phase transitions as wet slurries of individual soil fractions which were cooled or heated at controlled rates under a carbon dioxide atmosphere. Freezing and melting of ice was studied as a function of water/soil mass ratio, soil particle size, and thermal-cycle rate. Comparison tests were done under the same conditions with U.S. Geological Survey standard rock powders.

Gooding, J. L.

1987-05-01

271

Effects of temperatures near the freezing point on N2O emissions, denitrification and on the abundance and structure of nitrifying and denitrifying soil communities.  

PubMed

Climate warming in temperate regions may lead to decreased soil temperatures over winter as a result of reduced snow cover. We examined the effects of temperatures near the freezing point on N(2)O emissions, denitrification, and on the abundance and structure of soil nitrifiers and denitrifiers. Soil microcosms supplemented with NO3 - and/or NO3 - plus red clover residues were incubated for 120 days at -4 °C, -1 °C, +2 °C or +5 °C. Among microcosms amended with residues, N(2)O emission and/or denitrification increased with increasing temperature on Days 2 and 14. Interestingly, N(2)O emission and/or denitrification after Day 14 were the greatest at -1 °C. Substantial N(2) O emissions were only observed on Day 2 at +2 °C and +5 °C, while at -1 °C, N(2)O emissions were consistently detected over the duration of the experiment. Abundances of ammonia oxidizing bacteria (AOB) and archaea (AOA), Nitrospira-like bacteria and nirK denitrifiers were the lowest in soils at -4 °C, while abundances of Nitrobacter-like bacteria and nirS denitrifiers did not vary among temperatures. Community structures of nirK and nirS denitrifiers and Nitrobacter-like bacteria shifted between below-zero and above-zero temperatures. Structure of AOA and AOB communities also changed but not systematically among frozen and unfrozen temperatures. Results indicated shifts in some nitrifier and denitrifier communities with freezing and a surprising stimulation of N(2)O emissions at -1 °C when NO3 - and C are present. PMID:22882277

Wertz, Sophie; Goyer, Claudia; Zebarth, Bernie J; Burton, David L; Tatti, Enrico; Chantigny, Martin H; Filion, Martin

2012-08-29

272

A novel particle engineering technology to enhance dissolution of poorly water soluble drugs: spray-freezing into liquid.  

PubMed

A novel cryogenic spray-freezing into liquid (SFL) process was developed to produce microparticulate powders consisting of an active pharmaceutical ingredient (API) molecularly embedded within a pharmaceutical excipient matrix. In the SFL process, a feed solution containing the API was atomized beneath the surface of a cryogenic liquid such that the liquid-liquid impingement between the feed and cryogenic liquids resulted in intense atomization into microdroplets, which were frozen instantaneously into microparticles. The SFL micronized powder was obtained following lyophilization of the frozen microparticles. The objective of this study was to develop a particle engineering technology to produce micronized powders of the hydrophobic drug, danazol, complexed with hydroxypropyl-beta-cyclodextrin (HPbetaCD) and to compare these SFL micronized powders to inclusion complex powders produced from other techniques, such as co-grinding of dry powder mixtures and lyophilization of bulk solutions. Danazol and HPbetaCD were dissolved in a water/tetrahydrofuran cosolvent mixture prior to SFL processing or slow freezing. Identical quantities of the API and HPbetaCD used in the solutions were co-ground in a mortar and pestle and blended to produce a co-ground physical mixture for comparison. The powder samples were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy, surface area analysis, and dissolution testing. The results provided by DSC, XRD, and FTIR suggested the formation of inclusion complexes by both slow-freezing and SFL. However, the specific surface area was significantly higher for the latter. Dissolution results suggested that equilibration of the danazol/HPbetaCD solution prior to SFL processing was required to produce the most soluble conformation of the resulting inclusion complex following SFL. SFL micronized powders exhibited better dissolution profiles than the slowly frozen aggregate powder. Results indicated that micronized SFL inclusion complex powders dissolved faster in aqueous dissolution media than inclusion complexes formed by conventional techniques due to higher surface areas and stabilized inclusion complexes obtained by ultra-rapid freezing. PMID:12445556

Rogers, True L; Nelsen, Andrew C; Hu, Jiahui; Brown, Judith N; Sarkari, Marazban; Young, Timothy J; Johnston, Keith P; Williams, Robert O

2002-11-01

273

Recent Advances in Point-of-Access Water Quality Monitoring  

NASA Astrophysics Data System (ADS)

Clean water is one of our most valuable natural resources. In addition to providing safe drinking water it assures functional ecosystems that support fisheries and recreation. Human population growth and its associated increased demands on water pose risks to maintaining acceptable water quality. It is vital to assess source waters and the aquatic systems that receive inputs from industrial waste and sewage treatment plants, storm water systems, and runoff from urban and agricultural lands. Rapid and confident assessments of aquatic resources form the basis for sound environmental management. Current methods engaged in tracing the presence of various bacteria in water employ bulky laboratory equipment and are time consuming. Thus, real-time water quality monitoring is essential for National and International Health and Safety. Environmental water monitoring includes measurements of physical characteristics (e.g. pH, temperature, conductivity), chemical parameters (e.g. oxygen, alkalinity, nitrogen and phosphorus compounds), and abundance of certain biological taxa. Monitoring could also include assays of biological activity such as alkaline phosphatase, tests for toxins such as microcystins and direct measurements of pollutants such as heavy metals or hydrocarbons. Real time detection can significantly reduce the level of damage and also the cost to remedy the problem. This paper presents overview of state-of-the-art methods and devices used for point-of-access water quality monitoring and suggest further developments in this area.

Korostynska, O.; Arshak, K.; Velusamy, V.; Arshak, A.; Vaseashta, Ashok

274

Modeling the contribution of point sources and non-point sources to Thachin River water pollution.  

PubMed

Major rivers in developing and emerging countries suffer increasingly of severe degradation of water quality. The current study uses a mathematical Material Flow Analysis (MMFA) as a complementary approach to address the degradation of river water quality due to nutrient pollution in the Thachin River Basin in Central Thailand. This paper gives an overview of the origins and flow paths of the various point- and non-point pollution sources in the Thachin River Basin (in terms of nitrogen and phosphorus) and quantifies their relative importance within the system. The key parameters influencing the main nutrient flows are determined and possible mitigation measures discussed. The results show that aquaculture (as a point source) and rice farming (as a non-point source) are the key nutrient sources in the Thachin River Basin. Other point sources such as pig farms, households and industries, which were previously cited as the most relevant pollution sources in terms of organic pollution, play less significant roles in comparison. This order of importance shifts when considering the model results for the provincial level. Crosschecks with secondary data and field studies confirm the plausibility of our simulations. Specific nutrient loads for the pollution sources are derived; these can be used for a first broad quantification of nutrient pollution in comparable river basins. Based on an identification of the sensitive model parameters, possible mitigation scenarios are determined and their potential to reduce the nutrient load evaluated. A comparison of simulated nutrient loads with measured nutrient concentrations shows that nutrient retention in the river system may be significant. Sedimentation in the slow flowing surface water network as well as nitrogen emission to the air from the warm oxygen deficient waters are certainly partly responsible, but also wetlands along the river banks could play an important role as nutrient sinks. PMID:19501876

Schaffner, Monika; Bader, Hans-Peter; Scheidegger, Ruth

2009-06-06

275

Critical freezing rate in freeze drying nanocrystal dispersions.  

PubMed

Recent advances in nanoparticle technologies have significantly enhanced the oral and parenteral delivery of poorly water-soluble active pharmaceutical ingredients (APIs). However, reports have been limited on the various drying procedures to convert a liquid nanocrystal dispersions into solid dosage forms. The solid dosage form should consist of nanocrystals that can readily reconstitute into their original size upon dissolution in water. Herein, the freeze drying process of nanocrystal dispersions was examined at varying freezing rates (speed of freezing interface). As freezing rate decreases, more particle-particle aggregation developed. A critical freezing rate, below which the dried nanocrystals cannot be re-dispersed, was identified based on the plot of the particle size of reconstituted nanocrystals versus freezing rate. Freeze drying at a freezing rate near the critical value produces dry powders of bimodal particle size distribution after re-dispersion. In addition, API concentration was found to significantly affect the critical freezing rate and therefore the re-dispersibility of dry powders. The concept of critical freezing rate is critical for the development of solid dosage forms of liquid nanocrystal dispersions. PMID:16430987

Lee, Jonghwi; Cheng, Yu

2006-01-23

276

Rapid determination of vial heat transfer parameters using tunable diode laser absorption spectroscopy (TDLAS) in response to step-changes in pressure set-point during freeze-drying.  

PubMed

The purpose of this study was to perform a rapid determination of vial heat transfer parameters, that is, the contact parameter K(cs) and the separation distance l(v), using the sublimation rate profiles measured by tunable diode laser absorption spectroscopy (TDLAS). In this study, each size of vial was filled with pure water followed by a freeze-drying cycle using a LyoStar II dryer (FTS Systems) with step-changes of the chamber pressure set-point at to 25, 50, 100, 200, 300, and 400 mTorr. K(cs) was independently determined by nonlinear parameter estimation using the sublimation rates measured at the pressure set-point of 25 mTorr. After obtaining K(cs), the l(v) value for each vial size was determined by nonlinear parameter estimation using the pooled sublimation rate profiles obtained at 25 to 400 mTorr. The vial heat transfer coefficient K(v), as a function of the chamber pressure, was readily calculated, using the obtained K(cs) and l(v) values. It is interesting to note the significant difference in K(v) of two similar types of 10 mL Schott tubing vials, primary due to the geometry of the vial-bottom, as demonstrated by the images of the contact areas of the vial-bottom. PMID:18683861

Kuu, Wei Y; Nail, Steven L; Sacha, Gregory

2009-03-01

277

Natural freezing as a wastewater treatment method: E. coli inactivation capacity  

Microsoft Academic Search

Inactivation capacity of E. coli (strain ATCC 15597) in water by natural freezing was examined via two freezing methods: spray freezing and freezing in a freezer. The effect of freezing temperature (?5, ?15 and ?35°C), storage time, freeze–thaw cycles on the survival of the test organism were investigated. In addition, the number of cells injured by the freezing process was

W. Gao; D. W. Smith; Y. Li

2006-01-01

278

Dilution of impurities in water triple point cells  

NASA Astrophysics Data System (ADS)

Controlled amounts of Si and Na impurities (0.1 to 0.5 ?mol.mol-1 of Si and 0.2 to 1 ?mol.mol-1 of Na) were diluted in the high-purity water of triple point of water (TPW) cells before sealing the cells. Water samples drawn from the manufactured doped cells were analyzed with high-resolution Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The TPW temperature of one of the doped cells (the cell that showed a good agreement between the nominal Si and Na amounts and the Si and Na amounts measured by ICP-MS) was measured for different water/ice relative contents. The observed TPW depression was compared to 1) the TPW depression expected from the nominal doping and 2) the TPW depression expected from the total impurity content measured by ICP-MS.

Peruzzi, A.; Dobre, M.; Strouse, G. F.; van Geel, J.; Davis, C.

2013-09-01

279

7 CFR 305.18 - Quick freeze treatment schedule.  

Code of Federal Regulations, 2010 CFR

...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...

2010-01-01

280

7 CFR 305.18 - Quick freeze treatment schedule.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 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...

2009-01-01

281

Organic Solutes in Freezing Tolerance  

Microsoft Academic Search

The accumulation of high levels of low-molecular-weight solutes (polyhydric alcohols, saccharides) provides cryoprotection to freeze-tolerant animals by minimizing, via colligative effects, the percentage of body water converted to extracellular ice and the extent of cell volume reduction. Many freeze-tolerant insects accumulate high levels of polyols during autumn cold hardening, whereas freeze-tolerant frogs respond to ice formation in peripheral tissues by

Kenneth B. Storey

1997-01-01

282

Peculiar thermodynamics of the second critical point in supercooled water.  

PubMed

On the basis of the principle of critical-point universality, we examine the peculiar thermodynamics of the liquid-liquid critical point in supercooled water. We show that the liquid-liquid criticality in water represents a special kind of critical behavior in fluids, intermediate between two limiting cases: the lattice gas, commonly used to model liquid-vapor transitions, and the lattice liquid, a weakly compressible liquid with an entropy-driven phase separation. While the ordering field in the lattice gas is associated with the chemical potential and the order parameter with the density, in the lattice liquid the ordering field is the temperature and the order parameter is the entropy. The behavior of supercooled water is much closer to lattice-liquid behavior than to lattice-gas behavior. Using new experimental data recently obtained by Mishima [J. Chem. Phys. 2010, 133, 144503], we have revised the parametric scaled equation of state, previously suggested by Fuentevilla and Anisimov [Phys. Rev. Lett. 2006, 97, 195702], and obtain a consistent description of the thermodynamic anomalies of supercooled water by adjusting linear backgrounds, one critical amplitude, and the critical pressure. We also show how the lattice-liquid description affects the finite-size scaling description of supercooled water in confined media. PMID:21661753

Bertrand, C E; Anisimov, M A

2011-06-10

283

Freezing of phosphocholine headgroup in fully hydrated sphingomyelin bilayers and its effect on the dynamics of nonfreezable water at subzero temperatures.  

PubMed

Differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy are applied to characterize the nonfreezable water molecules in fully hydrated D2O/sphingomyelin at temperatures below 0 degrees C. Upon cooling, DSC thermogram displays two thermal transitions peaked at -11 and -34 degrees C. The high-temperature exothermic transition corresponds to the freezing of the bulk D2O, and the low-temperature transition, which has not previously been reported, can be ascribed to the freezing of the phosphocholine headgroup in the lipid bilayer. The dynamics of nonfreezable water are also studied by 2H NMR T1 (spin-lattice relaxation time) and T2e (spin-spin relaxation time obtained by two pulse echo) measurements at 30.7 MHz and at temperatures down to -110 degrees C. The temperature dependence of the T1 relaxation time is characterized by a distinct minimum value of 2.1 +/- 0.1 ms at -30 degrees C. T2e is discontinuous at temperature around -70 degrees C, indicating another freezing-like event for the bound water at this temperature. Analysis of the relaxation data suggest that nonfreezable water undergoes both fast and slow motions at characteristic NMR time scales. The slow motions are affected when the lipid headgroup freezes. PMID:1649825

Wu, W G; Chi, L M; Yang, T S; Fang, S Y

1991-07-25

284

Aspects of Freezing Rain Simulation and Testing.  

National Technical Information Service (NTIS)

The paper examines first the available information on freezing rain and freezing drizzle in an attempt to define the applicable parameters, viz. temperature, precipitation rate (or liquid water content), drop size, and wind speed, in order to permit repre...

J. R. Stallabrass

1983-01-01

285

Tetrameric assembly of CHIP28 water channels in liposomes and cell membranes: a freeze-fracture study  

PubMed Central

Channel forming integral protein of 28 kD (CHIP28) functions as a water channel in erythrocytes, kidney proximal tubule and thin descending limb of Henle. CHIP28 morphology was examined by freeze-fracture EM in proteoliposomes reconstituted with purified CHIP28, CHO cells stably transfected with CHIP28k cDNA, and rat kidney tubules. Liposomes reconstituted with HPLC-purified CHIP28 from human erythrocytes had a high osmotic water permeability (Pf0.04 cm/s) that was inhibited by HgCl2. Freeze-fracture replicas showed a fairly uniform set of intramembrane particles (IMPs); no IMPs were observed in liposomes without incorporated protein. By rotary shadowing, the IMPs had a diameter of 8.5 +/- 1.3 nm (mean +/- SD); many IMPs consisted of a distinct arrangement of four smaller subunits surrounding a central depression. IMPs of similar size and appearance were seen on the P-face of plasma membranes from CHIP28k-transfected (but not mock-transfected) CHO cells, rat thin descending limb (TDL) of Henle, and S3 segment of proximal straight tubules. A distinctive network of complementary IMP imprints was observed on the E-face of CHIP28-containing plasma membranes. The densities of IMPs in the size range of CHIP28 IMPs, determined by non-linear regression, were (in IMPs/microns 2): 2,494 in CHO cells, 5,785 in TDL, and 1,928 in proximal straight tubules; predicted Pf, based on the CHIP28 single channel water permeability of 3.6 x 10(-14) cm3/S (10 degrees C), was in good agreement with measured Pf of 0.027 cm/S, 0.075 cm/S, and 0.031 cm/S, respectively, in these cell types. Assuming that each CHIP28 monomer is a right cylindrical pore of length 5 nm and density 1.3 g/cm3, the monomer diameter would be 3.2 nm; a symmetrical arrangement of four cylinders would have a greatest diameter of 7.2 nm, which after correction for the thickness of platinum deposit, is similar to the measured IMP diameter of approximately 8.5 nm. These results provide a morphological signature for CHIP28 water channels and evidence for a tetrameric assembly of CHIP28 monomers in reconstituted proteoliposomes and cell membranes.

1993-01-01

286

A thermodynamic limit of the melting/freezing processes of water under strongly hydrophobic nanoscopic confinement.  

PubMed

We studied liquid water confined within nanopores which present a high level of hydrophobicity thanks to a new method of synthesis. We found that the liquid state persists down to temperatures much lower than in the bulk and in hydrophilic materials of comparable sizes, allowing us to define a thermodynamic limit for the melting/crystallization of water. PMID:20126756

Deschamps, Johnny; Audonnet, Fabrice; Brodie-Linder, Nancy; Schoeffel, Markus; Alba-Simionesco, Christiane

2009-12-23

287

Comparison of soil freezing curve and soil water curve data for Windsor sandy loam  

Microsoft Academic Search

Unfrozen water content as a function of temperature was measured in the laboratory using pulsed nuclear magnetic resonance (PNMR) for a Windsor sandy loam soil. The PNMR data were related to previously measured soil moisture retention data through the modified Clausius-Clapeyron equation, with suitable adjustment for surface tension. The transformed measured unfrozen water content data and the previously measured soil

Patrick B. Black; Allen R. Tice

1989-01-01

288

Viruses in Metropolitan Waters: Concentration by Polyelectrolytes, Freeze Concentration, and Ultrafiltration  

Microsoft Academic Search

Viruses in natural waters and their importance to public health have become debatable and speculative in the absence of substantive field studies designed to isolate and identify them in metropolitan waters. Here is a report on several techniques investigated as part of a collaborative effort by two agencies.

S. H. Rubenstein; J. Fenters; H. Orbach; N. Shuber; J. Reed; E. Molloy

1973-01-01

289

Elimination of bicarbonate interference in the binding of U(VI) in mill-waters to freeze-dried Chlorella vulgaris  

Microsoft Academic Search

Freeze-dried preparations of Chlorella vulgaris will accumulate U(Vl) from alkaline, bicarbonate-containing waters collected from uranium mill process streams, provided that the pH is pre-adjusted to between 4.0 and 6.0. Bicarbonate ion complexes the uranyl ion in these waters and seriously interferes with the binding of U(Vl) to the algal cells at pH values above 6.0. No binding of U(Vl) to

Benjamin Greene; Michael T. Henzl; J. Michael Hosea; Dennis W. Darnall

1986-01-01

290

Freeze-thaw-induced lateral transfer of non-conjugative plasmids by in situ transformation in Escherichia coli in natural waters and food extracts  

Microsoft Academic Search

Freeze-thaw treatment of condensed suspensions of mixed Escherichia coli strains in natural waters and food extracts caused in situ lateral transfer of non-conjugative plasmids. This phenomenon\\u000a also occurred in distilled water and LB broth, and after 1–2 months of preservation at ?20°C. The sensitivity of lateral transfer\\u000a towards DNase activity suggested the involvement of in situ transformation. There were no clear correlations between

Yuko Ishimoto; Shiho Kato; Sumio Maeda

2008-01-01

291

Groundwater flow with energy transport and water ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs  

NASA Astrophysics Data System (ADS)

In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison.

McKenzie, Jeffrey M.; Voss, Clifford I.; Siegel, Donald I.

2007-04-01

292

Comparison of Soil Freezing Curve and Soil Water Curve Data for Windsor Sandy Loam,  

National Technical Information Service (NTIS)

Unfrozen water content as a function of temperature was measured in the laboratory using nuclear magnetic resonance (NMR) for a Windsor sandy loam soil. The data were related to previously measured soil moisture retention data through the modified Clapeyr...

A. R. Tice P. B. Black

1988-01-01

293

SOLERAS - Solar-Powered Water Desalination Project at Yanbu: Indirect freeze desalination system performance  

Microsoft Academic Search

The desalination subsystem of the solar-powered desalination pilot project located at Yanbu, Saudi Arabia, was operated successfully for two years. Water production rates of 180 m³\\/day can be obtained for a period of 24 hours. In addition, once the proper procedures are followed, water production can continue for long periods of time at rates of 135 m³\\/day. Electrical energy costs

J. C. Zimmerman; N. Al-Abbadi

1987-01-01

294

Latent cold heat energy storage characteristics by means of direct-contact-freezing between oil droplets and cold water solution  

Microsoft Academic Search

Flow and solidification characteristics of paraffin oil droplets (tetradecane with the melting point of 5.8°C, the latent heat of fusion of 229.1 kJ\\/kg and the density of 770 kg\\/m3 at 6°C) ascending in a cold water solution are experimentally investigated. The tetradecane oil is injected from a cylindrical single hole nozzle into the cold water solution and it disperses and

Hideo Inaba; Kenji Sato

1997-01-01

295

POINT-OF-CONTACT/EXPERTISE LIST (WATER SUPPLY AND WATER RESOURCES DIVISION, NRMRL)  

EPA Science Inventory

NRMRL's Water Supply and Water Resources Division's (WSWRD's)Expertise/Point-of-Contact page lists research areas in the Division along with the names and telephone numbers for responsible individuals and their expertise. WSWRD conducts research to help prepare the primary and s...

296

Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena  

Microsoft Academic Search

This paper considers the emission of infrared characteristic radiation during the first order phase transitions of water (condensation and crystallization). Experimental results are analyzed in terms of their correspondence to the theoretical models. These models are based on the assumption that the particle's (atom, molecule, or cluster) transition from the higher energetic level (vapor or liquid) to a lower one

Vitali A. Tatartchenko

2010-01-01

297

Micronized powders of a poorly water soluble drug produced by a spray-freezing into liquid-emulsion process.  

PubMed

The purpose of this paper is to investigate the influence of the emulsion composition of the feed liquid on physicochemical characteristics of drug-loaded powders produced by spray-freezing into liquid (SFL) micronization, and to compare the SFL emulsion process to the SFL solution process. Danazol was formulated with polyvinyl alcohol (MW 22,000), poloxamer 407, and polyvinylpyrrolidone K-15 in a 2:1:1:1 weight ratio (40% active pharmaceutical ingredient (API) potency based on dry weight). Emulsions were formulated in ratios up to 20:1:1:1 (87% API potency based on dry weight). Ethyl acetate/water or dichloromethane/water mixtures were used to produce o/w emulsions for SFL micronization, and a tetrahydrofuran/water mixture was used to formulate the feed solutions. Micronized SFL powders were characterized by X-ray diffraction, surface area, scanning and transmission electron microscopy, contact angle and dissolution. Emulsions containing danazol in the internal oil phase and processed by SFL produced micronized powders containing amorphous drug. The surface area increased as drug and excipient concentrations were increased. Surface areas ranged from 8.9 m(2)/g (SFL powder from solution) to 83.1 m(2)/g (SFL powder from emulsion). Danazol contained in micronized SFL powders from emulsion and solution was 100% dissolved in the dissolution media within 2 min, which was significantly faster than the dissolution of non-SFL processed controls investigated (<50% in 2 min). Micronized SFL powders produced from emulsion had similar dissolution enhancement compared to those produced from solution, but higher quantities could be SFL processed from emulsions. Potencies of up to 87% yielded powders with rapid wetting and dissolution when utilizing feed emulsions instead of solutions. Large-scale SFL product batches were manufactured using lower solvent quantities and higher drug concentrations via emulsion formulations, thus demonstrating the usefulness of the SFL micronization technology in pharmaceutical development. PMID:12637092

Rogers, True L; Overhoff, Kirk A; Shah, Parag; Santiago, Patricia; Yacaman, Miguel J; Johnston, Keith P; Williams, Robert O

2003-03-01

298

State of Water in Confinement near Hydrophilic Surfaces Below the Freezing Temperature  

NASA Astrophysics Data System (ADS)

The main goal of the research is to find a relationship between the dynamic and the structural properties of water in hydrated heterogeneous systems. The results of dielectric spectroscopy studies of hydrated matrixes of porous glasses, clays and hydrated powder of Lysozyme are presented in wide frequency and temperature intervals. It is shown that for all systems studied the low temperature relaxation process demonstrates Arrhenius kinetics and exhibits a Cole-Cole (CC) behavior. A new phenomenological approach has been recently presented (see Puzenko A, Ben Ishai P, Feldman Yu, Phys Rev Lett 105:037601, 2010) that clarifies the physical mechanism of the dipole-matrix interaction in complex systems (CS) underlying the CC behaviour. A comparison porous glass with clays helps one to understand the specific adsorbed water dynamics due to the variety in the distribution of hydration centers.

Greenbaum (Gutina), A.; Puzenko, Alexander A.; Vasilyeva, M.; Feldman, Yu.

299

Numerical simulation of water transport and intracellular ice formation for freezing of endothelial cells.  

PubMed

Endothelial cell detachment may cause failure of blood vessel and corneal cryopreservation, and thus successful cryopreservation of endothelial cells is regarded to be the first step to optimize cryopreservation of endothelial cells containing tissues. In this study, the pre-determined biophysical parameters were incorporated into the model for intracellular ice formation (IIF) and the growth of intracellular ice crystals (ICG) to calculate cell water loss, supercooling of intracellular solution, intracellular ice formation and the growth of intracellular ice crystals. The optimal protocols were determined according to the combination effect of both solution injury and IIF injury. PMID:23435709

Zhao, G; Xu, Y; Ding, W P; Hu, M B

300

Interrelations Between Cement and Concrete Properties. Part 5. Freezing-and-Thawing Durability, Saturation, Water Loss and Absorption, Dynamic Modulus.  

National Technical Information Service (NTIS)

The concretes described in earlier parts of this series were subjected to laboratory freezing and thawing tests, and measurements were made of the weight loss, dynamic modulus, durability factor, and number of cycles required to reach 40 percent reduction...

R. L. Blaine H. T. Arni

1971-01-01

301

[Methods of vapour-phase extraction and extractive freezing for the analysis of organic substances dissolved in mineral waters of the Sochi spa area].  

PubMed

The chromatomass-spectrometry method was for the first time employed to study organic substances isolated by vapour-phase extraction from the Matseta sulfide-containing mineral water near Sochi. These substances are found to contain sulphur in different valent forms. A new technique has been developed for the detection of monobasic C2-C6 carboxylic acids in natural mineral water based on the combination of sequential vapour extraction and extractive freezing of the analytes. The proposed method is readily reproducible and has a detection limit of 0.03 mg/l for the analysis of carboxylic acids in water. PMID:19639697

Bekhterev, V N; Kabina, E A; Chekhova, T M; Ostapishin, V D

302

Stem water transport and freeze-thaw xylem embolism in conifers and angiosperms in a Tasmanian treeline heath  

Microsoft Academic Search

The effect of freezing on stem xylem hydraulic conductivity and leaf chlorophyll a fluorescence was measured in 12 tree and shrub species from a treeline heath in Tasmania, Australia. Reduction in stem hydraulic conductivity after a single freeze-thaw cycle was minimal in conifers and the vessel-less angiosperm species Tasmannia lanceolata (Winteraceae), whereas mean loss of conductivity in vessel-forming angiosperms fell

Taylor S. Feild; Tim Brodribb

2001-01-01

303

Novel ultra-rapid freezing particle engineering process for enhancement of dissolution rates of poorly water-soluble drugs  

Microsoft Academic Search

An ultra-rapid freezing (URF) technology has been developed to produce high surface area powders composed of solid solutions of an active pharmaceutical ingredient (API) and a polymer stabilizer. A solution of API and polymer excipient(s) is spread on a cold solid surface to form a thin film that freezes in 50ms to 1s. This study provides an understanding of how

Kirk A. Overhoff; Josh D. Engstrom; Bo Chen; Brian D. Scherzer; Thomas E. Milner; Keith P. Johnston; Robert O. Williams III

2007-01-01

304

A land surface soil moisture data assimilation framework in consideration of the model subgrid-scale heterogeneity and soil water thawing and freezing  

Microsoft Academic Search

The Ensemble Kalman Filter (EnKF) is well known and widely used in land data assimilation for its high precision and simple\\u000a operation. The land surface models used as the forecast operator in a land data assimilation system are usually designed to\\u000a consider the model subgrid-heterogeneity and soil water thawing and freezing. To neglect their effects could lead to some\\u000a errors

XiangJun Tian; ZhengHui Xie

2008-01-01

305

The Effect of Whey Protein Isolate-Dextran Conjugates on the Freeze-Thaw Stability of Oil-in-Water Emulsions  

Microsoft Academic Search

This study examines the impact of Maillard-type conjugates formed between whey protein isolate (WPI) and the nonionic polysaccharide dextran by dry heating at 80°C for 2 hours (conjugate 1) and at 60°C for 5 days (conjugate 2) on the freeze-thaw stability of oil-in-water emulsions. Emulsions stabilized with WPI, WPI-dextran mixture, conjugates 1 and 2, were prepared using microfluidizer, respectively, and

Duoxia Xu; Fang Yuan; Xiaoya Wang; Xiaoting Li; Zhanqun Hou; Yanxiang Gao

2010-01-01

306

Design of self-dispersible dry nanosuspension through wet milling and spray freeze-drying for poorly water-soluble drugs.  

PubMed

The purpose of the present research is to establish a novel nanosizing technique starting from wet nano-milling, named "dry nanosuspension" technique for poorly water-soluble drugs. The spray freeze-drying (SFD) method was applied instead of the spray-drying one previously developed. Drug particles were milled in the aqueous solution of dispersing agents using an oscillating beads-milling apparatus. The milled nanosuspension was sprayed to the surface of liquid nitrogen, and the resultant iced droplets were freeze-dried to obtain the powdery product. The loading ratio of a dispersing agent was investigated to enhance its redispersing property. Dry nanosuspension, which could be spontaneously dispersed into original nanosuspension in water, was obtained by SFD process. It was assumed that self dispersion property would be attributed to its structure with porous network, in which the primary milled drug crystals were embedded. Such unique structure contributed greatly to immediate release behaviors of the drug in gastrointestinal buffered media. These pharmaceutical properties were enhanced by increasing the ratio of the dispersing agent to the drug and the solid content in suspension to be sprayed. The present technique via wet milling and spray freeze-drying processes would be a novel dissolution-enhanced technology for poorly water-soluble drugs. PMID:23907001

Niwa, Toshiyuki; Danjo, Kazumi

2013-07-29

307

Ground-water movement and water quality in Lake Point, Tooele County, Utah, 1999-2003  

USGS Publications Warehouse

Water-level and water-quality data in Lake Point, Tooele County, Utah, were collected during August 1999 through August 2003. Water levels in Lake Point generally declined about 1 to 2 feet from July 2001 to July 2003, likely because of less-than-average precipitation. Ground water generally flows in two directions from the Oquirrh Mountains. One component flows north toward the regional topographic low, Great Salt Lake. The other component generally flows southwest toward a substantial spring complex, Factory/Dunne's Pond. This southwest component flows through a coarse gravel deposit believed to be a shoreline feature of historic Lake Bonneville. The dominant water-quality trend in Lake Point is an increase in dissolved-solids concentration with proximity to Great Salt Lake. The water type changes from calcium-bicarbonate adjacent to the Oquirrh Mountains to sodium-chloride with proximity to Great Salt Lake. Evaluation of chloride-bromide weight ratios indicates a mixture of fresher recharge waters with a brine similar to what currently exists in Great Salt Lake.

Kenney, T. A.; Wright, S. J.; Stolp, B. J.

2006-01-01

308

Analyzing the effect of seasonal water cover variability and freeze-thaw timing on methane emissions from boreal and arctic soils  

NASA Astrophysics Data System (ADS)

Here we present a new technique to detect the extent of surface water cover in boreal and arctic regions using the QuikSCAT microwave backscatter signal from 2000 to 2008, and compare these data to satellite and flask based measurements of atmospheric methane concentrations. The QuikSCAT scatterometer provides a high resolution (2.5 km, daily) long term record of fractional water cover, and is particularly sensitive to the timing of spring thaw and flooding. Interannual and seasonal variability in surface water cover drive changes in methane emissions from lakes and wetlands across the arctic and boreal region. We identify several regions where lake extent has significantly increased or decreased over the period 2000 to 2008, and evaluate changes in the seasonal cycle of water cover over this period. We combine the QuikSCAT water cover product with satellite derived estimates of soil freeze and thaw, and compare these records to atmospheric methane data from the NOAA CMDL Flask network and the satellite based TES (Aura) CH4 measurements to identify ‘pulses’ of methane emitted during periods of active freezing and thawing. We also estimate the possible effects of long-term changes in the thaw season length (from 1988 to 2009) and fractional water cover area (2000 to 2008) on methane emissions from boreal and arctic soils.

Smith-Downey, N.; Fu, R.

2009-12-01

309

Freezing induces a loss of freeze tolerance in an overwintering insect.  

PubMed Central

Cold-hardy insects overwinter by one of two main strategies: freeze tolerance and freeze avoidance by supercooling. As a general model, many freeze-tolerant species overwinter in extreme climates, freeze above -10 degrees C via induction by ice-nucleating agents, and once frozen, can survive at temperatures of up to 40 degrees C or more below the initial freezing temperature or supercooling point (SCP). It has been assumed that the SCP of freeze-tolerant insects is unaffected by the freezing process and that the freeze-tolerant state is therefore retained in winter though successive freeze-thaw cycles of the body tissues and fluids. Studies on the freeze-tolerant larva of the hoverfly Syrphus ribesii reveal this assumption to be untrue. When a sample with a mean 'first freeze' SCP of -7.6 degrees C (range of -5 degrees C to -9.5 degrees C) were cooled, either to -10 degrees C or to their individual SCP, on five occasions, the mean SCP was significantly depressed, with some larvae subsequently freezing as low as -28 degrees C. Only larvae that froze at the same consistently high temperature above -10 degrees C were alive after being frozen five times. The wider occurrence of this phenomenon would require a fundamental reassessment of the dynamics and distinctions of the freeze-tolerant and freeze-avoiding strategies of insect overwintering.

Brown, C L; Bale, J S; Walters, K F A

2004-01-01

310

Effect of 2,4-dichlorophenol on DPPC\\/water liposomes studied by X-ray and freeze-fracture electron microscopy  

Microsoft Academic Search

The effect of 2,4-dichlorophenol (DCP) was studied on the fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)—water liposomes. The structure and the thermotropic phase behaviour of the liposomes was examined in the presence of DCP (DCP\\/DPPC molar ratio, varied from 2×10?2 up to 1) using small- and wide-angle X-ray scattering (SAXS, WAXS) and freeze-fracture electron microscopy. The structural behaviour of the DPPC\\/DCP\\/water system was

Ágnes Csiszár; Erwin Klumpp; Attila Bóta; Krisztián Szegedi

2003-01-01

311

Freezing Point Depression within a Shear Field and the Effect of a Shear Field on Crystallization of Bi-Pb-Sn-Cd Alloy  

Microsoft Academic Search

A melting (or freezing) temperature, in general, is considered to be dependent only on pressure. However, in a recent paper a new idea was proposed, i.e. the temperature of a phase transition between a liquid and a solid is depressed when a shear field is applied to the materials. In this investigation an experimental study was made with a Bi-Pb-Sn-Cd

Hiroshi Mishina; Tadashi Sasada; Kunio Watanabe

1986-01-01

312

Entropy, Disorder, and Freezing  

NASA Astrophysics Data System (ADS)

It is argued that the usual view that entropy is a measure of "disorder" is problematic and that there exist systems at high density, for which packing considerations dominate, where a spatially ordered state has a higher entropy than a disordered one. A classic example is a system of hard-sphere atoms, for which freezing is known to be purely entropy driven. Such a model has relevance to the real world, since it provides a good qualitative (and nearly quantitative) description of solid-liquid coexistence in simple systems such as argon. An analogy based on the packing of suitcases is given to illustrate the main point. A simple classroom demonstration is also described in which an analog simulation of the freezing of hard particles is performed.

Laird, Brian B.

1999-10-01

313

Impact of large herbivores at artificial watering points compared to that at natural watering points in Kruger National Park, South Africa  

Microsoft Academic Search

Two pairs of a natural and an artificial watering point in each of the four largest land systems in the Kruger National Park, South Africa were randomly selected for study. The herbaceous community composition and basal cover were measured in transects starting at the water and radiating to 100m from the water. The community composition was converted to herbaceous forage

I. Thrash

1998-01-01

314

Impact of water activity, temperature, and physical state on the storage stability of Lactobacillus paracasei ssp. paracasei freeze-dried in a lactose matrix.  

PubMed

The aim of this study was to determine whether the combined effect of water activity and temperature on inactivation rates of freeze-dried microorganisms in a lactose matrix could be explained in terms of the glass transition theory. The stabilized glass transition temperature, Tg, of the freeze-dried products was determined by differential scanning calorimetry at two different temperatures, T (20 and 37 degrees C), and different water activities (0.07-0.48). This information served as a basis for defining conditions of T and water activity, which led to storage of the bacteria in the glassy (T < Tg) and nonglassy (T > Tg) states. The rates of inactivation of the dry microorganisms subjected to different storage conditions were determined by plate counts and could be described by first-order kinetics. Rates were analyzed as a function of water activity, storage temperature, and the difference between Tg and T. Inactivation below Tg was low; however, Tg could not be regarded as an absolute threshold of bacteria stability during storage. When the cells were stored in the nonglassy state (T > Tg), inactivation proceeded faster, however, not as rapid as suggested by the temperature dependence of the viscosity above the glass transition temperature. Furthermore, the first-order rate constant, k, was dependent on the storage temperature per se rather than on the temperature difference between the glass transition temperature and the storage temperature (T - Tg). PMID:17636886

Higl, Bettina; Kurtmann, Lone; Carlsen, Charlotte U; Ratjen, Jennifer; Först, Petra; Skibsted, Leif H; Kulozik, Ulrich; Risbo, Jens

2007-07-17

315

Recovery of White Blood Cells After Freezing.  

National Technical Information Service (NTIS)

Whereas the red cells recover from the actual congelation of all the water freezable at -3C, the neutrophils are already injured when only a fraction of the water freezable at -1.5C is congealed. Electron microscope studies of freeze-dried or freeze-subsi...

B. J. Luyet L. J. Menz G. L. Rapatz D. Rasmussen

1971-01-01

316

Optical method of sub-cooled water recognition in dew point hygrometer  

Microsoft Academic Search

A new optical method of sub-cooled water recognition in dew point hygrometer is presented. The physical phenomenon of sub-cooled water and its influence on the hygrometer accuracy is described. A hypothesis relating scattering of light by water and ice layers is proposed. A new type of dew point hygrometer based on the silicone mirror with the embedded capacitive detector and

Jerzy Weremczuk

2000-01-01

317

Mechanisms of freezing damage.  

PubMed

Freezing of aqueous systems involves numerous simultaneous changes but this review concentrates on direct effects of the formation of ice and the consequent concentration of solutes in the remaining liquid phase. It is generally believed that cell injury at low cooling rates is principally due to the concentration of both intracellular and extracellular electrolytes and that cryoprotectants act by reducing this build-up. New experimental data are presented to support this explanation; we find that the extent of damage to human red blood cells during freezing in solutions of sodium chloride/glycerol/water can be quantitatively accounted for by the increase in solute concentration. However, we also show that a given degree of damage occurs at lower concentrations of solute in the presence of higher concentrations of glycerol; it appears that glycerol contributes an element of damage itself. Recently published studies from Mazur's laboratory have suggested that the dominant damaging factor at low cooling rates is actually the reduction of the quantity of unfrozen water rather than the corresponding increase in salt concentration that accompanies freezing. These data are re-evaluated, and it is argued that the experimental results could equally well be explained by a susceptibility of cells to shrinkage and re-expansion as the concentration of external impermeant solutes first increases during freezing and then decreases during thawing. It is concluded that external ice probably has no directly damaging effect upon dilute suspensions of cells. However, it is also argued that ice is directly damaging whenever it forms intracellularly, and also when it forms extracellularly in densely packed cell suspensions. In the latter case the damage is probably due to recrystallization of the ice masses during thawing. Extracellular ice also has a directly damaging effect when tissues and organs are frozen. The difficulties of designing experimental methods that will yield unequivocal results is emphasized, and consequently the above conclusions must be regarded as tentative at the present time. PMID:3332492

Pegg, D E

1987-01-01

318

Transepidermal water loss sensor based on fast dew point hygrometer  

Microsoft Academic Search

A new idea of moisture content in human skin measurement with use of fast dew point hygrometer sensor is presented in the report. The hygrometer construction based on integration in the single semiconductor sensor structure with the impedance detector, the thermoresistor and the heater is described in the paper. Both the experimental results of the dew point hygrometer tests as

R. Jachowicz; J. Weremczuk; G. Tarapata

2005-01-01

319

Stability against freezing of aqueous solutions on early Mars  

NASA Astrophysics Data System (ADS)

Many features of the Martian landscape are thought to have been formed by liquid water flow and water-related mineralogies on the surface of Mars are widespread and abundant. Several lines of evidence, however, suggest that Mars has been cold with mean global temperatures well below the freezing point of pure water. Martian climate modellers considering a combination of greenhouse gases at a range of partial pressures find it challenging to simulate global mean Martian surface temperatures above 273K, and local thermal sources cannot account for the widespread distribution of hydrated and evaporitic minerals throughout the Martian landscape. Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox. Here we model the freezing and evaporation processes of Martian fluids with a composition resulting from the weathering of basalts, as reflected in the chemical compositions at Mars landing sites. Our results show that a significant fraction of weathering fluids loaded with Si, Fe, S, Mg, Ca, Cl, Na, K and Al remain in the liquid state at temperatures well below 273K. We tested our model by analysing the mineralogies yielded by the evolution of the solutions: the resulting mineral assemblages are analogous to those actually identified on the Martian surface. This stability against freezing of Martian fluids can explain saline liquid water activity on the surface of Mars at mean global temperatures well below 273K.

Fairén, Alberto G.; Davila, Alfonso F.; Gago-Duport, Luis; Amils, Ricardo; McKay, Christopher P.

2009-05-01

320

Simulation of Heat Transfer in Freezing Soils Using ABAQUS  

Microsoft Academic Search

Freezing saturated soils are mixtures of solid particles, water, and ice. Heat transfer in freezing soils is a complex process because of the multi-phase nature of the mixture. The phase change of the liquid part adds complexity, since not all water changes phase at the freezing temperature. Difficulties with convergence are known to appear when simulating the process. A numerical

Ming Zhu; Radoslaw L. Michalowski

321

Refrigeration Requirements for Ice Cream Freezing1  

Microsoft Academic Search

The heat removed from an ice cream mix during freezing is a function of several variables with composition predominating. This investigation compared experimental calorimetric results with predicted refrig- eration requirements. The predictions were obtained by adding the contributions of sensible heat of mix above the initial freezing point, sensible heat of unfrozen mix portion, latent heat and sensible heat of

D. R. Heldman; T. I. Hedrick

1970-01-01

322

Freezing precipitation in Canada  

Microsoft Academic Search

Renewed interest in freezing precipitation processes and their cause have resulted in a requirement for an updated, detailed climatology of freezing precipitation in Canada. Previous work in this area was very limited in terms of the period of record and the extent of the analysis.In this study national maps were prepared of occurrence frequencies of freezing rain, freezing drizzle and

R. A. Stuart; G. A. Isaac

1999-01-01

323

Conformational and bioactivity analysis of insulin: freeze-drying TBA/water co-solvent system in the presence of surfactant and sugar.  

PubMed

Despite the extensive research into the freeze-drying of aqueous solutions of proteins, it remains unknown whether proteins can survive the lyophilization process in a water-organic co-solvent system and how the process and additives affect the structural stability and activity of the proteins. In the present study, a conformational analysis of insulin in the absence/presence of bile salt and trehalose was carried out, before and after freeze-drying of a tert-butyl alcohol (TBA)/water co-solvent system at volume ratios of TBA to water ranging from 50/50 to 0/100. The study involved the use of ultraviolet derivative and fluorescence spectroscopy, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Also the bioactivity of insulin was evaluated in vivo using the streptozotocin (STZ)-induced diabetic mice as an animal model. Initial investigations indicate that the extent of the structural change of insulin depends significantly both on the TBA content and on the concentration of additives, such as sodium deoxycholate, prior to lyophilization. This could be accounted for by the phase behavior properties of the TBA/water co-solvent system, surface denaturation together with the selective and/or forced dispersion of insulin during phase separation. Lyophilized insulin in the presence of bile salt and trehalose retained more of its bioactivity and native-like structure in the solid state compared with that in the absence of additives at various TBA/water ratios, although in all cases there was a major and reversible rearrangement of secondary structure after rehydration, except for insulin at 50% TBA (v/v). Furthermore, both lyophilization in non-eutectic systems and less structural changes in the formulation process lead to more bioactivity. PMID:19136051

Zhang, Yong; Deng, Yingjie; Wang, Xueli; Xu, Jinghua; Li, Zhengqiang

2008-12-24

324

Pedotransfer functions for point and parametric estimations of soil water retention curve  

Microsoft Academic Search

A water retention curve is required for the simulation studies of water and solute transport in unsaturated or va- dose zone. Unlike the direct measurement of water retention data, pedotransfer functions (PTFs) have attracted the attention of researchers for determining water retention curves from basic soil properties. The objective of this study was to develop and validate point and parametric

H. Merdun

2006-01-01

325

Is there a second critical point in liquid water?  

Microsoft Academic Search

The supercooled and stretched regions of the phase diagram of simulated liquid water are investigated by calculating the equation of state of the ST2 and TIP4P pair-potentials. We find that simulated water does not display a re-entrant spinodal and that the projection of the density maximum line in the plane of pressure and temperature becomes positively sloped on stretching. The

H. E. Stanley; C. A. Angell; U. Essmann; M. Hemmati; P. H. Poole; F. Sciortino

1994-01-01

326

Kinetic analysis of cooking losses from beef and other animal muscles heated in a water bath--effect of sample dimensions and prior freezing and ageing.  

PubMed

Cooking loss kinetics were measured on cubes and parallelepipeds of beef Semimembranosus muscle ranging from 1 cm × 1 cm × 1 cm to 7 cm × 7 cm × 28 cm in size. The samples were water bath-heated at three different temperatures, i.e. 50°C, 70°C and 90°C, and for five different times. Temperatures were simulated to help interpret the results. Pre-freezing the sample, difference in ageing time, and in muscle fiber orientation had little influence on cooking losses. At longer treatment times, the effects of sample size disappeared and cooking losses depended only on the temperature. A selection of the tests was repeated on four other beef muscles and on veal, horse and lamb Semimembranosus muscle. Kinetics followed similar curves in all cases but resulted in different final water contents. The shape of the kinetics curves suggests first-order kinetics. PMID:21333460

Oillic, Samuel; Lemoine, Eric; Gros, Jean-Bernard; Kondjoyan, Alain

2011-01-14

327

24 CFR 3285.603 - Water supply.  

Code of Federal Regulations, 2010 CFR

...and the inlet. (2) The water riser for the shutoff valve...d) Freezing protection. Water line crossovers completed during...protected from freezing. The freeze protection design requirements...freezing temperatures, the water connection must be...

2009-04-01

328

24 CFR 3285.603 - Water supply.  

Code of Federal Regulations, 2010 CFR

...and the inlet. (2) The water riser for the shutoff valve...d) Freezing protection. Water line crossovers completed during...protected from freezing. The freeze protection design requirements...freezing temperatures, the water connection must be...

2010-04-01

329

RADON REMOVAL USING POINT-OF-ENTRY WATER TREATMENT TECHNIQUES  

EPA Science Inventory

The purpose of this EPA Cooperative Agreement was to evaluate the performance of POE granular activated carbon (GAG), and diffused bubble and bubble place aeration systems treating a ground water supply containing radon (35,620 + or - 6,717 pCi/L. he pattern of loading to the uni...

330

Survival of freezing by free-living Antarctic soil nematodes.  

PubMed

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

Convey, P; Worland, M R

331

Influence of non-water-soluble placebo pellets of different sizes on the characteristics of orally disintegrating tablets manufactured by freeze-drying.  

PubMed

The present study describes the development of an orally disintegrating tablet containing a non-water-soluble drug delivery system. A model system was applied to evaluate the effect of different-sized particles on tablet characteristics. Cellets were incorporated into tablets prepared by freeze-drying from a 100 mg/mL mannitol or sucrose solution. Particle size distributions were 200-355 µm for Cellets 200 (C200) and 500-710 µm for Cellets 500 (C500). An examination of the tablets revealed that the particles could not be sufficiently embedded in mannitol because of its crystalline nature. The tablet hardness was also inadequate. In contrast, the hardness of sucrose tablets was increased by the addition of Cellets 500. Therefore, the sucrose-based formulation was studied further. Binders [hydroxyethylstarch, sodium alginate, methylcellulose (MC), and gelatin] were added in different concentrations, and tablets were made either with or without placebo pellets. A positive effect of the Cellets on the hardness of tablets was identified. Furthermore, disintegration time could be clearly reduced by Cellets for tablets made from 100 mg/mL sucrose with addition of 10 mg/mL MC, 20 or 40 mg/mL gelatin. The freeze-dried tablet index revealed that the formulations of sucrose with 50 mg/mL hydroxyethylstarch or 20 mg/mL gelatin were particularly advantageous. PMID:23568590

Stange, Ulrike; Führling, Christian; Gieseler, Henning

2013-04-09

332

Screening and identification of early warning algal species for metal contamination in fresh water bodies polluted from point and non-point sources  

Microsoft Academic Search

The water bodies of Lucknow, Unnao and Kanpur (U.P.), India polluted through various point and non point sources were found\\u000a to be either eutrophic or oligotrophic in nature. These water bodies supported a great number of algal diversity, which varied\\u000a seasonally depending upon the physico-chemical properties of water. Further, the water bodies polluted through non point sources\\u000a supports diverse algal

U. N. Rai; Smita Dubey; O. P. Shukla; S. Dwivedi; R. D. Tripathi

2008-01-01

333

A Comparative Risk Approach to Assessing Point-of-Use Water treatment Systems in Developing Countries  

Microsoft Academic Search

Unsafe water is a leadingcause of death and disease in economically disadvantaged societies. The development of centralized large-scale water treatment and supply systems has proven to be a slow, expensive strategy to provide safe drinking water in many low-income countries. Governments and non-governmental organizations have therefore increasingly been promoting point-of-use water treatment technologies in communities without reliable municipal water supplies.

A. Varghese

334

Preliminary Exploration on Water Pollution from NonPoint Source in XiangXi River  

Microsoft Academic Search

Eutrophication is a worldwide pollution problem, when the point source pollution is efficiently controlled, pollution load from non-point source has the increasing proportion in the total load. Xiangxi River is selected as the research demonstration area to conduct preliminary study on non-point source pollution for frequent water bloom. Non-point source pollution factors are analyzed in Xiangxi River such as precipitation,

Song Linxu; Liu Ping

2010-01-01

335

Freezing and anoxia tolerance of slugs: a metabolic perspective  

Microsoft Academic Search

Freezing survival was assessed in three species of terrestrial slugs, a holarctic but native North American species, Deroceras laeve, and two species introduced from Europe, D. reticulatum and Arion\\u000a circumscriptus. The introduced species showed very poor freezing survival. Supercooling points of the introduced species were quite high\\u000a (??3°C) and their freezing survival was very poor, limited to short-term freezing at

Kenneth B. Storey; Janet M. Storey; Thomas A. Churchill

2007-01-01

336

Elimination of bicarbonate interference in the binding of U(VI) in mill-waters to freeze-dried Chlorella vulgaris  

SciTech Connect

Freeze-dried preparations of Chlorella vulgaris will accumulate U(Vl) from alkaline, bicarbonate-containing waters collected from uranium mill process streams, provided that the pH is pre-adjusted to between 4.0 and 6.0. Bicarbonate ion complexes the uranyl ion in these waters and seriously interferes with the binding of U(Vl) to the algal cells at pH values above 6.0. No binding of U(Vl) to the algae occurred at the natural pH of 8.0 when Chlorella vulgaris was suspended in untreated mull-waters containing up to 2.5 x 10/sup -4/M U(Vl). However, when the pH of these waters was lowered from 8.0 to near 5.0, with nitric acid, nearly quantitative binding of U(Vl) to the alga was achieved. Binding is rapid and largely unaffected by ions including Na/sup +/, Cl/sup -/, NO/sub 3//sup -/, /sup -/OAc, and SO/sub 4//sup 2 -/. Our results indicate that provided steps are taken to eliminate bicarbonate interference, such as adjustment of the pH to near 5.0, dried algal biomass could prove useful for the removal and recovery of U(Vl) from high carbonate-containing waters.

Greene, B.; Henzl, M.T.; Hosea, J.M.; Darnall, D.W.

1986-01-01

337

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, April 1--June 31, 1995  

SciTech Connect

The cost of treating the water produced in association with oil and natural gas has prevented the completion of wells in economically marginal formations and has caused low-productivity wells to be prematurely shut-in. An economical method for treatment, disposal, and/or reuse of these waters on a commercial-scale would assist the oil and natural gas industries in continuing to provide reasonably priced fuels to the consumer by allowing for economic production from marginal, unconventional, and depleted reserves. A treatment process that could produce water of suitable quality for reuse would also be advantageous for municipal, industrial, and agricultural development in the arid western US where there is significant oil and natural gas production. The natural processes of freezing and evaporation can be coupled to effectively and inexpensively treat waters produced in association with natural gas. This document delineates research conducted, during the time period from 4/1/95 to 6/30/95, for evaluating the technical and economic feasibility of this water treatment process. The research required for development of this process can be completed in two tasks: Task 1--Literature Survey and Preliminary Economic Analysis; Task 2--Laboratory-Scale Process Evaluation and Field Demonstration of the Process. The main work this quarter focused on a re-evaluation of process economics based on lab-scale process simulation results.

Boysen, J.; Morotti, J.

1995-07-01

338

Freezing Tolerance in Mytilus Edulis.  

National Technical Information Service (NTIS)

Mytilus edulis tolerates freezing to a tissue temperature of -10 deg C, while Venus mercenaria tolerates only -6 deg C. In both species, tissues are injured when 64 per cent of cellular water has been moved to form ice. In Mytilus, 20 percent of cell wate...

R. J. Williams

1969-01-01

339

Ice Accretion in Freezing Rain.  

National Technical Information Service (NTIS)

This report describes a detailed heat-balance ice accretion model, including the important heat fluxes in freezing rain and allowing the accretion of runoff water in the form of icicles. It also presents a simple algorithm for calculating the ice load on ...

K. F. Jones

1996-01-01

340

EVALUATING POINT-NONPOINT SOURCE WATER QUALITY TRADING IN A RARITAN RIVER BASIN SUB-WATERSHED  

EPA Science Inventory

This project addresses water quality issues in the Raritan River Basin of New Jersey. It will build upon an existing study that determined the technical feasibility of implementing a point-nonpoint source water quality trading program in the Basin. Water quality trading is ...

341

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

PubMed

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

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

2012-04-01

342

Freezing rate determination by the isotopic composition of the ice  

Microsoft Academic Search

The distribution of an isotopic species, HDO (deuterium) or H218O (oxygen), in ice formed by the migration of a well-defined freezing front in water is dependent on the freezing rate. Development of a box diffusion model combined with the boundary layer concept leads to a possibility of prediction of the freezing rate in nature by the determination of the isotopic

Roland Souchez; Jean-Louis Tison; Jean Jouzel

1987-01-01

343

Reptile freeze tolerance: metabolism and gene expression.  

PubMed

Terrestrially hibernating reptiles that live in seasonally cold climates need effective strategies of cold hardiness to survive the winter. Use of thermally buffered hibernacula is very important but when exposure to temperatures below 0 degrees C cannot be avoided, either freeze avoidance (supercooling) or freeze tolerance strategies can be employed, sometimes by the same species depending on environmental conditions. Several reptile species display ecologically relevant freeze tolerance, surviving for extended times with 50% or more of their total body water frozen. The use of colligative cryoprotectants by reptiles is poorly developed but metabolic and enzymatic adaptations providing anoxia tolerance and antioxidant defense are important aids to freezing survival. New studies using DNA array screening are examining the role of freeze-responsive gene expression. Three categories of freeze responsive genes have been identified from recent screenings of liver and heart from freeze-exposed (5h post-nucleation at -2.5 degrees C) hatchling painted turtles, Chrysemys picta marginata. These genes encode (a) proteins involved in iron binding, (b) enzymes of antioxidant defense, and (c) serine protease inhibitors. The same genes were up-regulated by anoxia exposure (4 h of N2 gas exposure at 5 degrees C) of the hatchlings which suggests that these defenses for freeze tolerance are aimed at counteracting the injurious effects of the ischemia imposed by plasma freezing. PMID:16321368

Storey, Kenneth B

2006-02-01

344

Effect of Shrimp Chitin and Shrimp Chitin Hydrolysate on the Freeze-Induced Denaturation, and on the Amount of Unfreezable Water of Wanieso Lizardfish Myofibrillar Protein  

NASA Astrophysics Data System (ADS)

In view of potential utilization of shrimp waste, shrimp chitin (SC) and shrimp chitin hydrolysate (SCH) were prepared from 3 kinds of shrimp species, namely: black tiger shrimp Penaeus monodon, endeavour shrimp Metapenaeus endeavouri and giant freshwater shrimp Macrobrachium rosenbergii. The effects of 5% SC and SCH (dry weight) on the state of water and on the denaturation of wanieso lizardfish Saurida wanieso myofibrillar protein (Mf) were evaluated based on changes in Mf Ca-ATPase activity and the amount of unfreezable water during frozen storage. Each effect was compared with those of Mf without additives (control) and Mf with glucose. The changes in Ca-ATPase activity of control and Mf with SC during frozen storage were exhibited biphasic pattern while those of SCH and glucose exhibited monophasic pattern. The amount of unfreezable water of Mf with SC was lower than that of control while those of Mf with SCH and glucose were higher than that of control. Present findings suggested that the preventive effect of SCH on freeze-induced denaturation of Mf is caused by the stabilizing the hydrated water molecule surrounding the Mf.

Somjit, Kingduean; Kongpun, Orawan; Osatomi, Kiyoshi; Hara, Kenji; Nozaki, Yukinori

345

Freezing survival, body ice content and blood composition of the freeze-tolerant European common lizard, Lacerta vivipara  

Microsoft Academic Search

To investigate the freeze tolerance of the European common lizard, Lacerta vivipara, we froze 17 individuals to body temperatures as low as -4 °C under controlled laboratory conditions. The data show that this species tolerates the freezing of 50% of total body water and can survive freezing exposures of at least 24-h duration. Currently, this represents the best known development

Y. Voituron; J. Storey; C. Grenot; K. Storey

2002-01-01

346

Effect of freezing and thawing processes on soil aggregate stability  

Microsoft Academic Search

The effect of freezing and thawing on wet aggregate stability of soils formed on different parent materials was determined for different aggregate size groups (0.0–1.0; 1.0–2.0; and 2.0–4.0 mm), different water contents and for various freezing and thawing cycles (three, six and nine times) and freezing temperatures (?4 and ?18 °C). The initial wet aggregate stability decreased with freeze–thaw treatments

Taskin Oztas; Ferhan Fayetorbay

2003-01-01

347

Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature  

Microsoft Academic Search

The equilibrium fractionation factors of oxygen and hydrogen isotopes between liquid water and water vapor have been precisely determined from 25 to 350°C on the VSMOW-SLAP scale, using three different types of apparatus with static or dynamic techniques for the sampling of water vapor. Our results for both oxygen and hydrogen isotope fractionation factors between 25 and 100°C are in

Juske Horita; David J. Wesolowski

1994-01-01

348

Artifacts associated with quick-freezing and freeze-drying.  

PubMed

We have studied the structures produced when nonbiological samples were subjected to quick-freezing and freeze-drying with a liquid helium cooled freeze-slamming device. Samples examined in this way included sodium chloride, sucrose, and Tris buffer. A variety of filamentlike and trabeculumlike structures were formed in these preparations. These structures may represent eutectic mixtures formed during the growth of small ice crystals during the freezing process, and exposed during the rapid sublimation of pure ice during the etching process. Samples of biological membranes (isolated chloroplast membranes) were prepared in various buffers by means of this technique. In distilled water, excellent replicas of membrane surfaces were obtained. In salt solutions, however, the membranes appeared to be embedded in a network of thin filaments appearing very much like a cytoskeletal lattice. It is concluded that extreme caution must be used when employing this preparation technique for studies of cell architecture, and that extensive washing of cell components in distilled water may be necessary to obtain faithful representations of cell structure. PMID:6338243

Miller, K R; Prescott, C S; Jacobs, T L; Lassignal, N L

1983-02-01

349

The Use of Thermowell Bushes at the Triple Point of Water for Improving Repeatability  

Microsoft Academic Search

Water triple point cells are essential for realization of the International Temperature Scale of 1990 (ITS-90). There is some\\u000a evidence that achieving the ultimate performance of water triple point cells may be restricted by the variation in the position\\u000a of the platinum resistance thermometer at the bottom of the re-entrant well, and that the variation in position is not completely

E. Smith; G. Machin; J. Gray; R. Veltcheva

2010-01-01

350

The Long-Term Drift of Triple-Point-of-Water Cells  

Microsoft Academic Search

As the triple point of water is of great importance for the International Temperature Scale of 1990 (ITS-90) and for the definition\\u000a of the unit of thermodynamic temperature, its long-term stability has attracted a great deal of attention. In a study of long-term\\u000a stability, a mystery has been uncovered. Some triple-point-of-water cells remain stable for many decades, while others decrease

X. K. Yan; C. F. Ma; Z. Zhang; H. L. Wu; P. Qiu; Y. L. Feng; J. T. Zhang; Y. N. Duan

2008-01-01

351

The Long-Term Drift of Triple-Point-of-Water Cells  

Microsoft Academic Search

As the triple point of water is of great importance for the International Temperature Scale of 1990 (ITS-90) and for the definition of the unit of thermodynamic temperature, its long-term stability has attracted a great deal of attention. In a study of long-term stability, a mystery has been uncovered. Some triple-point-of-water cells remain stable for many decades, while others decrease

X. K. Yan; C. F. Ma; Z. Zhang; H. L. Wu; P. Qiu; Y. L. Feng; J. T. Zhang; Y. N. Duan

2008-01-01

352

Passive freeze protection for solar collectors  

Microsoft Academic Search

Freeze damage is an important practical problem for water-type solar collectors. In the past, electric resistance heaters, drain systems, and separate ethylene glycol-water collection loops have commonly been used to prevent freezing. These techniques are effective but involve active components such as controls, heaters, valves, solenoids, pumps, heat exchangers, etc., that increase costs, degrade reliability and\\/or reduce overall efficiency. This

L. W. Bickle

1975-01-01

353

POINT-OF-USE TREATMENT OF DRINKING WATER IN SAN YSIDRO, NM  

EPA Science Inventory

A study was conducted to determine whether point-of-use reverse osmosis units could satisfactorily function in lieu of central treatment to remove arsenic and fluoride from the drinking water supply of a small community. Point-of-use treatment was evaluated for removal efficiency...

354

Molecular biology of freezing tolerance.  

PubMed

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

Storey, Kenneth B; Storey, Janet M

2013-07-01

355

Hysteresis of Soil Point Water Retention Functions Determined by Neutron Radiography  

NASA Astrophysics Data System (ADS)

Soil point water retention functions are needed for modeling flow and transport in partially-saturated porous media. Such functions are usually determined by inverse modeling of average water retention data measured experimentally on columns of finite length. However, the resulting functions are subject to the appropriateness of the chosen model, as well as the initial and boundary condition assumptions employed. Soil point water retention functions are rarely measured directly and when they are the focus is invariably on the main drying branch. Previous direct measurement methods include time domain reflectometry and gamma beam attenuation. Here we report direct measurements of the main wetting and drying branches of the point water retention function using neutron radiography. The measurements were performed on a coarse sand (Flint #13) packed into 2.6 cm diameter x 4 cm long aluminum cylinders at the NIST BT-2 (50 ?m resolution) and ORNL-HFIR CG1D (70 ?m resolution) imaging beamlines. The sand columns were saturated with water and then drained and rewetted under quasi-equilibrium conditions using a hanging water column setup. 2048 x 2048 pixel images of the transmitted flux of neutrons through the column were acquired at each imposed suction (~10-15 suction values per experiment). Volumetric water contents were calculated on a pixel by pixel basis using Beer-Lambert’s law in conjunction with beam hardening and geometric corrections. The pixel rows were averaged and combined with information on the known distribution of suctions within the column to give 2048 point drying and wetting functions for each experiment. The point functions exhibited pronounced hysteresis and varied with column height, possibly due to differences in porosity caused by the packing procedure employed. Predicted point functions, extracted from the hanging water column volumetric data using the TrueCell inverse modeling procedure, showed very good agreement with the range of point functions measured within the column using neutron radiography. Extension of these experiments to 3-dimensions using neutron tomography is planned.

Perfect, E.; Kang, M.; Bilheux, H.; Willis, K. J.; Horita, J.; Warren, J.; Cheng, C.

2010-12-01

356

Modification of halocline source waters during freezing on the Beaufort Sea shelf: evidence from oxygen isotopes and dissolved nutrients  

Microsoft Academic Search

During some, but not all winters, waters on the Mackenzie shelf of the Beaufort Sea become sufficiently saline to ventilate the halocline of the adjacent Canada Basin. This occurred in March 1988, at which time a survey of the temperature, salinity, dissolved nutrient and 18O properties of the ventilating waters was completed. The regional hydrography of 1988 was very similar

Humfrey Melling; Robert M. Moore

1995-01-01

357

Fate of Arsenic at a Landfill Plume Discharge Point Into Surface Water, Central Massachusetts  

Microsoft Academic Search

Fate of dissolved arsenic in ground water at the point of discharge into surface water raises a concern about the public health and the environment due to a potential of arsenic accumulation in the bottom sediments. Dissolved arsenic may become sorbed on amorphous precipitates of ferric hydroxides formed by a changing redox potential during the discharge and then locally deposited.

W. C. Brandon; R. Hon

2004-01-01

358

A high pressure calorimetric experiment to validate the liquid-liquid critical point hypothesis in water  

Microsoft Academic Search

An experimental proposal to test the existence of a liquid-liquid critical point in water, based on high pressure calorimetric measurements, is presented on this paper. Considering the existence of an intramolecular correlation in the water molecule we show how the response of the specific heat at high pressure is different depending on the existence, or not, of the second critical

Manuel I. Marques

2007-01-01

359

Pointed water vapor radiometer corrections for accurate Global Positioning System surveying  

Microsoft Academic Search

Delay of the Global Positioning System (GPS) signal due to atmospheric water vapor is a major source of error in GPS surveying. Improved vertical accuracy is important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air and ground-based gravimetry, ice dynamics, and volcanology. We conducted a GPS survey using water vapor radiometers (WVRs) pointed

Randolph Ware; Christian Rocken; Fredrick Solheim; Teresa Van Hove; Chris Alber; James Johnson

1993-01-01

360

Improved Estimates of the Isotopic Correction Constants for the Triple Point of Water  

Microsoft Academic Search

In 2006, the CIPM clarified the definition of the kelvin by specifying the isotopic composition of the water to be used in the realization of the triple point. At the same time, the Consultative Committee for Thermometry gave recommended values for the isotopic correction constants to be used for water departing from the specified composition. However, the uncertainties in the

D. R. White; W. L. Tew

2010-01-01

361

Comparison of Optimization and Two-point Methods in Estimation of Soil Water Retention Curve  

Microsoft Academic Search

Soil water retention curve (SWRC) is one of the soil hydraulic properties in which its direct measurement is time consuming and expensive. Since, its measurement is unavoidable in study of environmental sciences i.e. investigation of unsaturated hydraulic conductivity and solute transport, in this study the attempt is to predict soil water retention curve from two measured points. By using Cresswell

B. Ghanbarian-Alavijeh; A. M. Liaghat; G. Huang

2009-01-01

362

Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs  

USGS Publications Warehouse

In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison. ?? 2006 Elsevier Ltd. All rights reserved.

McKenzie, J. M.; Voss, C. I.; Siegel, D. I.

2007-01-01

363

Impact of Freezing and Thawing Soil Conditions on the Movement of Nutrients by Water from Rural Lands.  

National Technical Information Service (NTIS)

A model was developed to predict transformations and vertical movement of manurial nitrogen through unsaturated soil profiles following early spring manure application. Processes treated in the model include water movement in unsaturated soil, nitrate dis...

G. D. Bubenzer J. C. Converse

1975-01-01

364

The thermodynamics of freezing soils  

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

365

Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena; Part 3: Experimental data  

NASA Astrophysics Data System (ADS)

This paper is the third one from the series of papers with the same titles published in this journal. The papers consider the infrared characteristic radiation (IRCR) during the first order phase transitions of water: crystallization, water vapor condensation, and water vapor deposition. Experimental results are analyzed in terms of their correspondence to the theoretical model. This model is based on the assertion that the particle's (atom, molecule, or cluster) transition from the higher energetic level in a metastable phase (vapor or liquid) to a lower level in a stable phase (liquid or crystal) produces an emission of one or more photons. The energy of these photons depends on the latent energy of the phase transition and the character of bonds formed by the particle in the new phase. For all investigated substances, this energy falls in the infrared range. Recorded in the atmosphere, numerous sources of the infrared radiation seem to be a result of crystallization, condensation and deposition of water during fog and cloud formation. The effect under investigation must play a very important role in atmospheric phenomena: it is one of the sources of Earth's cooling; formation of hailstorm clouds is accompanied by intensive IRCR that could be detected for process characterization and meteorological warnings. IRCR seems to be used for atmospheric energy accumulation and together with the wind, falling water, solar and geothermal energies makes available the fifth source of ecologically pure energy.

Tatartchenko, V.; Liu, Yifan; Chen, Wenyuan; Smirnov, P.

2012-09-01

366

Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature  

SciTech Connect

The equilibrium fractionation factors of oxygen and hydrogen isotopes between liquid water and water vapor have been precisely determined from 25 to 350[degrees]C on the VSMOW-SLAP scale, using three different types of apparatus with static or dynamic techniques for the sampling of water vapor. The results for both oxygen and hydrogen isotope fractionation factors between 25 and 100[degrees]C are in excellent agreement with the literature. The results for the hydrogen isotope fractionation factor above 100[degrees]C also agree quantitatively with the literature values of Merlivat et al. (1963) and Bottinga (1968). The results for the hydrogen isotope fractionation factor obtained in this study and from most of the literature was regressed to the equation, 10[sup 3] ln [alpha][sub 1-v](D) = 1158.8(T[sup 3]/10[sup 9]) - 1620.1(T[sup 2]/10[sup 6]) + 794.84(T/10[sup 3]) - 161.04 + 2.9992(10[sup 9]/T[sup 3]), from 0[degrees]C to the critical temperature of water (374.1[degrees]C) within [+-]1.2(1[sigma]) (n = 157); T(K). The crossover temperature is 229 [+-] 13[degrees]C 1[sigma]. The values for the oxygen isotope fractionation factor between liquid water and water vapor are, however, at notable variance with the only dataset available above 100[degrees]C in the literature, which is systematically higher (av. + 0.15 in 10[sup 3] in [alpha][sub l-v] ([sup 18]O)) with large errors ([+-]0.23 in 1[sigma]). The results and most of the literature data below 100[degrees]C were regressed to the equation, 10[sup 3] ln [alpha][sub l-v]([sup 18]O) = -7.685 + 6.7123(10[sup 3]/T) - 1.6664(10[sup 6]/T[sup 2])+0.30541(10[sup 9]/T[sup 3]), from 0 to 374.1[degrees]C within [+-]0.11 (1[sigma]) (n = 112); T(K). A third water-steam isotope geothermometer, using the ratio of [Delta][delta]D/[Delta][delta][sup 18]O given by water and steam samples, is readily obtained from the above equations.

Horita, J.; Wesolowski, D.J. (Oak Ridge National Lab., TN (United States))

1994-08-01

367

Effects of anti-freeze concentration in the engine coolant on the cavitation temperature of a water pump  

Microsoft Academic Search

Improvements in engine-manufacturing technology have gradually increased the thermal efficiencies of engines as well as the burning temperature and pressure of fuels within the cylinders. Accordingly, greater heat dissipation are required. However, the volume of the radiators is constrained by the configuration of the engines, leading to excessive internal resistance in the engine-cooling system. Therefore, water pumps in engines are

K. David Huang; Sheng-Chung Tzeng; Wei-Ping Ma

2004-01-01

368

40 CFR 141.100 - Criteria and procedures for public water systems using point-of-entry devices.  

Code of Federal Regulations, 2013 CFR

...false Criteria and procedures for public water systems using point-of-entry devices...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Use of Non-Centralized...

2013-07-01

369

Cluster description of water-in-oil microemulsions near the critical and percolation points  

Microsoft Academic Search

Summary  The three-component ionic microemulsion system consisting of AOT\\/water\\/decane shows an unusual phase behavior in the vicinity\\u000a of room temperature. The phase diagram in the temperature-volume fraction (of the dispersed phase) plane exhibits a lower\\u000a consolute critical point at about 40 degrees centigrades and 10% volume fraction. A percolation line, starting from the vicinity\\u000a of the critical point, cuts across the

S. H. Chen; J. Rouch; F. Sciortino; P. Tartaglia

1994-01-01

370

Relation of ice growth rate to salt segregation during freezing of low-salinity sea water (Bothnian Bay, Baltic Sea)  

Microsoft Academic Search

Salt segregation and isotopic fractionation during sea-ice formation can be parameterized as a function of the ice growth rate. We performed a study to investigate if the salt segregation models derived for saline sea-ice studies are pertinent during the growth of Baltic Sea ice in brackish water. We used a time series of ice-salinity profiles and modeled growth rates to

Mats A. Granskog; Jari Uusikivi; Alberto Blanco Sequeiros; Eloni Sonninen

2006-01-01

371

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

PubMed

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

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

2013-03-26

372

Use of Pointed Water Vapor Radiometer Observations to Improve Vertical GPS Surveying Accuracy.  

NASA Astrophysics Data System (ADS)

Atmospheric water vapor is a source of propagation delay, and therefore error, in Global Positioning System (GPS) geodesy. While GPS geodesy is now capable of millimeter level positioning, unmodelled water vapor can result in errors of several centimeters. Anisotropies in water vapor observed at ground sites have prompted the investigation into their effect upon GPS geodesy. Driven by the geophysical community's desire for more accurate baseline measurements, several previous attempts to improve geodesy with pointed water vapor radiometer (WVR) observations yielded dubious results. The development of an accurate, stable, steerable portable microwave water vapor radiometer, as well as improved oxygen and water vapor line shape models, has made possible more accurate water vapor measurements along the propagation paths to the GPS satellites. This radiometer development started in 1987 with funding from the Department of Commerce and still continues. This thesis will discuss the considerations relating to ionospheric and atmospheric refractivity (which induces phase delay in GPS signals) and to atmospheric microwave absorption (related to the microwave radiometer observable, emission). The microwave radiometer, its development, and its theoretical and measured performance characteristics are also described. Finally, a four month field experiment, called WVR92, is described wherein pointed water vapor radiometer observations were incorporated into modified GPS analysis software to correct for anisotropies in water vapor. A factor of two improvement was realized over stochastic methods and over zenith only WVR measurements. An interesting corollary finding resulted from this field experiment; it was found that, if the GPS position software were allowed to estimate the tropospheric water vapor by minimizing position residuals in a least squares sense, the zenith difference in water vapor burdens between GPS antenna locations could be measured to within a millimeter or so. Absolute water vapor burdens can be determined if WVR observations are taken at one of the GPS sites. This finding is of great interest to the meteorological community, and has triggered the installation of GPS receivers for water vapor measurements at meteorological network sites.

Solheim, Fredrick Stuart

373

Liquid-like water in the upper surface of Mars - presence and properties  

NASA Astrophysics Data System (ADS)

Liquid layers of water can via adsorption develop on grain and mineral surfaces at and in the surface of Mars. The upper parts of these layers will freeze at temperatures clearly below the freezing point of bulk water (freezing point depression). This will be modeled in terms of a sandwich structure with layers of ice (top), liquid water (in between) and mineral surface (bottom) can evolve. Thickness (or number of mono-layers) of the liquid water layer and the related content of liquid-like water in dependence on the diurnal temperature variations, the freezing point depression temperatures of the unfrozen water, and the related equilibrium content of liquid water in surface soil are derived on the basis of this "sandwich model" with van der Waals interactions between the mineral-substrate and the ice layer. These results are discussed with respect to the mid- and low-latitudinal surface and shallow subsurface of Mars.

Möhlmann, D.

2007-08-01

374

Glass Transition in Biomolecules and the Liquid-Liquid Critical Point of Water  

NASA Astrophysics Data System (ADS)

Using molecular dynamics simulations, we investigate the relation between the dynamic transitions of biomolecules (lysozyme and DNA) and the dynamic and thermodynamic properties of hydration water. We find that the dynamic transition of the macromolecules, sometimes called a “protein glass transition,” occurs at the temperature of dynamic crossover in the diffusivity of hydration water and also coincides with the maxima of the isobaric specific heat CP and the temperature derivative of the orientational order parameter. We relate these findings to the hypothesis of a liquid-liquid critical point in water. Our simulations are consistent with the possibility that the protein glass transition results from crossing the Widom line, which is defined as the locus of correlation length maxima emanating from the hypothesized second critical point of water.

Kumar, Pradeep; Yan, Z.; Xu, L.; Mazza, M. G.; Buldyrev, S. V.; Chen, S.-H.; Sastry, S.; Stanley, H. E.

2006-10-01

375

Improved Estimates of the Isotopic Correction Constants for the Triple Point of Water  

Microsoft Academic Search

In 2006, the CIPM clarified the definition of the kelvin by specifying the isotopic composition of the water to be used in\\u000a the realization of the triple point. At the same time, the Consultative Committee for Thermometry gave recommended values\\u000a for the isotopic correction constants to be used for water departing from the specified composition. However, the uncertainties\\u000a in the

D. R. White; W. L. Tew

2010-01-01

376

Microbial risk assessment with the OAEL approach at water abstraction points in rural Kenya  

Microsoft Academic Search

US-based models for recreational water quality were applied to characterize the potential health risk (PHR) of infection with gastroenteritis (GI) and highly credible gastroenteritis (HCGI) illnesses from single exposure at several water abstraction points (WAPs) along the Njoro River in rural Kenya. Ambient geometric mean densities of Escherichia coli (EC) and intestinal enterococci (IE) were generally high (2–4log units of

Paul T. Yillia; Norbert Kreuzinger; Jude M. Mathooko; Ernest T. Ndomahina

2009-01-01

377

Surface freezing of n-octane nanodroplets  

NASA Astrophysics Data System (ADS)

Surface freezing, at temperatures up to a few degrees above the equilibrium melting point, has been observed for intermediate chain length (16<= i<= 50) n-alkanes [B. M. Ocko, X. Z. Wu, E. B. Sirota, S. K. Sinha, O. Gang and M. Deutsch, Phys. Rev. E, 1997, 55, 3164-3182]. Our recent experimental results suggest that surface freezing is also the first step when highly supercooled nanodroplets of n-octane crystallize. Our data yield surface and bulk nucleation rates on the order of ~1015/cm2.s and ~1022/cm3.s, respectively. Complementary molecular dynamics simulations also show that the surface of the droplet freezes almost immediately, and freezing of the remainder of the droplet progresses in a layer-by-layer manner.

Modak, Viraj; Pathak, Harshad; Thayer, Mitchell; Singer, Sherwin; Wyslouzil, Barbara

2013-05-01

378

The effects of sulfur mustard exposure and freezing on transdermal penetration of tritiated water through ex vivo pig skin.  

PubMed

The percutaneous absorption of tritiated water ((3)H(2)O) through sulfur mustard (SM) exposed abdominal pig skin was measured using in vitro Franz-type static diffusion cells. The barrier function to water permeation following exposure to liquid SM for 8 min and excision 3h later did not change significantly. A small, but statistically significant difference (P<0.05) in steady state penetration (Jss), permeability coefficient (Kp) and lag time (t(L)) of (3)H(2)O was observed between fresh skin and skin stored frozen (-20 °C) for up to two weeks. Steady-state penetration and Kp values were significantly higher (P < 0.05) in skin stored frozen compared with fresh skin. Fresh naïve skin had an average Kp of 1.65 × 10(-3) cm h(-1), whereas frozen naïve skin was 2.04 × 10(-3) cm h(-1). Fresh SM exposed skin had a mean Kp of 1.72 × 10(-3) cm h(-1), whereas frozen SM exposed skin was 2.31 × 10(-3) cm h(-1). Lag times were also shorter (P<0.05) in skin that had been stored frozen. Frozen, SM-exposed porcine abdominal skin may be used for in vitro penetration studies, but effects of treatment and storage on the barrier layer should be taken into account. PMID:23041075

Payne, O J; Graham, S J; Dalton, C H; Spencer, P M; Mansson, R; Jenner, J; Azeke, J; Braue, E

2012-10-04

379

Intracellular freezing, viability, and composition of fat body cells from freeze-intolerant larvae of Sarcophaga crassipalpis.  

PubMed

Although it is often assumed that survival of freezing requires that ice formation must be restricted to extracellular compartments, fat body cells from freeze-tolerant larvae of the gall fly, Eurosta solidaginis (Diptera, Tephritidae) survive intracellular freezing. Furthermore, these cells are highly susceptible to inoculative freezing by external ice, undergo extensive lipid coalescence upon thawing, and survive freezing better when glycerol is added to the suspension medium. To determine whether these traits are required for intracellular freeze tolerance or whether they are incidental and possessed by fat body cells in general, we investigated the capacity of fat body cells from nondiapause-destined and diapause-destined (i.e., cold-hardy) larvae of the freeze-intolerant flesh fly Sarcophaga crassipalpis (Diptera, Sarcophagidae) to survive intracellular freezing. Fat body cells from both types of larvae were highly susceptible to inoculative freezing; all cells froze between -3.7 to -6.2 degrees C. The highest rates for survival of intracellular freezing occurred at -5 degrees C. The addition of glycerol to the media markedly increased survival rates. Upon thawing, the fat body cells showed little or no lipid coalescence. Fat body cells from E. solidaginis had a water content of only 35% compared to cells from S. crassipalpis larvae that had 52-55%; cells with less water may be less likely to be damaged by mechanical forces during intracellular freezing. PMID:11746564

Davis, D J; Lee, R E

2001-12-01

380

Polymerization with freezing  

Microsoft Academic Search

Irreversible aggregation processes involving reactive and frozen clusters are investigated using the rate equation approach. In aggregation events, two clusters join irreversibly to form a larger cluster; additionally, reactive clusters may spontaneously freeze. Frozen clusters do not participate in merger events. Generally, freezing controls the nature of the aggregation process, as demonstrated by the final distribution of frozen clusters. The

E. Ben-Naim; P. L. Krapivsky

2005-01-01

381

Home Freezing of Seafoods.  

National Technical Information Service (NTIS)

Significant advances in freezing technology have been made within the past six years. Information is given on the selection of seafood for home freezing, for its preparation, packaging and storing, and finally on the proper use of the frozen product. Thre...

M. E. Waters

1974-01-01

382

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

383

Heat of Freezing and Melting of Sea Ice.  

National Technical Information Service (NTIS)

Computations are presented which show that the latent heat of freezing ice in equilibrium with sea water is less than that associated with freezing pure water at 0C. The difference is due primarily to a temperature effect that is opposed to some extent by...

D. Anderson

1966-01-01

384

Charge-Charge Liquid Structure Factor and the Freezing of Alkali Halides  

Microsoft Academic Search

The peak height of the charge-charge liquid structure factor SQQ in molten alkali halides is proposed as a criterion for freezing. Available data on molten alkali chlorides, when extrapolated to the freezing point suggests SQQ ? 5.

N. H. March; M. P. Tosi

1980-01-01

385

LANDSCAPE MODELS FOR SIMULATING WATER QUALITY AT POINT, FIELD, AND WATERSHED SCALES  

Microsoft Academic Search

In the last four decades, a plethora of models has been developed to simulate nonpoint-source (NPS) pollutant fate and transport at point, field, and watershed scales. Developed by experts in various disciplines, these models tend to reflect the needs of those disciplines. For example, the original intent of the solute transport models was to determine impact of water, nutrient, and

P. Srivastava; K. W. Migliaccio; J. Šim?nek

386

POINT-OF-USE TREATMENT OF DRINKING WATER IN SAN YSIDRO, NM  

EPA Science Inventory

This study was conducted to determine whether point-of-use (POU) reverse osmosis (RO) units could satisfactorily function in lieu of central treatment to remove arsenic and fluoride from the drinking water supply of San Ysidro, NM. POU treatment was evaluated for removal efficien...

387

Study of the Magnetic Field Effect on Commercial Thermistors using a Water Triple Point  

Microsoft Academic Search

The effect of a magnetic field on commercial thermistors was precisely studied in detail using the water triple point. A thermistor with a code of 44004 manufactured by YSI Inc. was found to show a small correction. Its orientation effect and sensor dependence was found also to be small. The correction Delta T (mK) against magnetic field B(T) was found

Koichi Nara

2005-01-01

388

Measuring the residual air pressure in triple-point-of-water cells  

Microsoft Academic Search

Residual gas pressure is one of the factors influencing the temperature realized by triple-point-of-water cells. This note describes a simple procedure for measuring and correcting for the residual air pressure in sealed cells. The procedure is applicable to any cell with a McLeod-gauge extension or sufficient remnant ‘seal-off’ tube to trap an air bubble.

D R White

2004-01-01

389

Issues in Ecology, Issue 03: Non Point Pollution of Surface Waters  

NSDL National Science Digital Library

This report addresses pollution of aquatic ecosystems that originate from multiple unidentified sources or non point sources. Non point sources of phosphorus and nitrogen are of concern as they cause eutrophication or excessive enrichment of surface waters. Effects and remediation strategies are discussed. Non point sources, such as agricultural, urban and atmospheric ones are discussed. Management techniques to reduce excess nutrient transport across landscapes and into bodies of water are explained. The report discusses the need to establish controversial Thresholds of unacceptable soil contamination. Issues in Ecology is an ongoing series of reports designed to present major ecological issues in an easy-to-read manner. This Issue summarizes the consensus of a panel of scientific experts based on the information that was current and available at the time of its publication in 1998.

Smith, Val

2010-02-16

390

Natural Wetlands Mediate Non-point Source Water Pollution From Irrigated Pastures  

NASA Astrophysics Data System (ADS)

Non-point source discharge from grazed pastures may be high in nutrients, sediment, and pathogens, three major contributors to water quality impairment in California. Intercepting pollution at its source and managing water quality within the landscape are essential to maintaining healthy downstream waters. We investigated the efficacy of flow-through wetlands interspersed throughout the agricultural landscape to reduce non-point source pollution of tailwater from cattle-grazed, irrigated pastures in the Sierra Nevada Foothills of California. Wetlands are known to positively impact water quality through ecological processes such as filtration, sedimentation, microbial transformations and plant uptake of nutrients. Influent and effluent water of small (0.25 ha), natural wetlands located downstream from flood irrigated pastures was analyzed for Escherichia coli, NO3-N, total N, total suspended solids (TSS), total P, and dissolved organic carbon (DOC) throughout two summer irrigation seasons (June to October). We compared reductions of sediment, nutrients and E. coli provided by a healthy, non-degraded wetland with reductions from flow through a channelized, degraded wetland. Large reductions in E. coli (>75%) and TSS (>50%) were observed in water exiting the healthy wetland while nutrient and DOC (~ 20%) concentrations were less affected by flow through the wetland. The channelized wetland provided smaller reductions in all constituents than did the non-degraded wetland. Results from this study demonstrate that small flow-through wetlands can improve water quality through the attenuation of E. coli and suspended sediments, and to a lesser degree DOC and nutrients.

Knox, K.; Dahlgren, R. A.; Tate, K. W.

2005-12-01

391

Dew-point hygrometry system for measurement of evaporative water loss in infants.  

PubMed

Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0 degree C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of approximately 0.02 mgH2O.cm-2.min-1 for normothermic baseline conditions and values up to 0.4 mgH2O.cm-2. min-1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss. PMID:9074995

Ariagno, R L; Glotzbach, S F; Baldwin, R B; Rector, D M; Bowley, S M; Moffat, R J

1997-03-01

392

Freezing of living cells: mechanisms and implications  

SciTech Connect

Cells can endure storage at low temperatures such as -196/sup 0/C for centuries. The challenge is to determine how they can survive both the cooling to such temperatures and the subsequent return to physiological conditions. A major factor is whether they freeze intracellularly. They do so if cooling is too rapid, because with rapid cooling insufficient cell water is removed osmotically to eliminate supercooling. Equations have been developed that describe the kinetics of this water loss and permit one to predict the likelihood of intracellular freezing as a function of cooling rate. Such predictions agree well with observations. Although the avoidance of intracellular freezing is usually necessary for survival, it is not sufficient. Slow freezing itself can be injurious. As ice forms outside the cell, the residual unfrozen medium forms channels of decreasing size and increasing solute concentration. The cells lie in the channels and shrink in osmotic response to the rising solute concentration. Prior theories have ascribed slow freezing injury to the concentration of solutes or the cell shrinkage. Recent experiments, however, indicate that the damage is due more to the decrease in the size of the unfrozen channels. This new view of the mechanism of slow freezing injury ought to facilitate the development of procedures for the preservation of complex assemblages of cells of biological, medical, and agricultural significance. 126 references, 18 figures, 2 tables.

Mazur, P.

1984-01-01

393

Cryoprotective dehydration and the resistance to inoculative freezing in the Antarctic midge, Belgica antarctica.  

PubMed

During winter, larvae of the Antarctic midge, Belgica antarctica (Diptera, Chironomidae), must endure 7-8 months of continuous subzero temperatures, encasement in a matrix of soil and ice, and severely desiccating conditions. This environment, along with the fact that larvae possess a high rate of water loss and are extremely tolerant of desiccation, may promote the use of cryoprotective dehydration as a strategy for winter survival. This study investigates the capacity of larvae to resist inoculative freezing and undergo cryoprotective dehydration at subzero temperatures. Slow cooling to -3 degrees C in an environment at equilibrium with the vapor pressure of ice reduced larval water content by approximately 40% and depressed the body fluid melting point more than threefold to -2.6 degrees C. This melting point depression was the result of the concentration of existing solutes (i.e. loss of body water) and the de novo synthesis of osmolytes. By day 14 of the subzero exposure, larval survival was still >95%, suggesting larvae have the capacity to undergo cryoprotective dehydration. However, under natural conditions the use of cryoprotective dehydration may be constrained by inoculative freezing as result of the insect's intimate contact with environmental ice. During slow cooling within a substrate of frozen soil, the ability of larvae to resist inoculative freezing and undergo cryoprotective dehydration was dependent upon the moisture content of the soil. As detected by a reduction of larval water content, the percentage of larvae that resisted inoculative freezing increased with decreasing soil moisture. These results suggest that larvae of the Antarctic midge have the capacity to resist inoculative freezing at relatively low soil moisture contents and likely undergo cryoprotective dehydration when exposed to subzero temperatures during the polar winter. PMID:18245628

Elnitsky, Michael A; Hayward, Scott A L; Rinehart, Joseph P; Denlinger, David L; Lee, Richard E

2008-02-01

394

33 CFR 334.412 - Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted area.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 2013-07-01 false Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...RESTRICTED AREA REGULATIONS § 334.412 Albemarle Sound, Pamlico Sound, Harvey Point and adjacent...

2013-07-01

395

Comparison of Optimization and Two-point Methods in Estimation of Soil Water Retention Curve  

NASA Astrophysics Data System (ADS)

Soil water retention curve (SWRC) is one of the soil hydraulic properties in which its direct measurement is time consuming and expensive. Since, its measurement is unavoidable in study of environmental sciences i.e. investigation of unsaturated hydraulic conductivity and solute transport, in this study the attempt is to predict soil water retention curve from two measured points. By using Cresswell and Paydar (1996) method (two-point method) and an optimization method developed in this study on the basis of two points of SWRC, parameters of Tyler and Wheatcraft (1990) model (fractal dimension and air entry value) were estimated and then water content at different matric potentials were estimated and compared with their measured values (n=180). For each method, we used both 3 and 1500 kPa (case 1) and 33 and 1500 kPa (case 2) as two points of SWRC. The calculated RMSE values showed that in the Creswell and Paydar (1996) method, there exists no significant difference between case 1 and case 2. However, the calculated RMSE value in case 2 (2.35) was slightly less than case 1 (2.37). The results also showed that the developed optimization method in this study had significantly less RMSE values for cases 1 (1.63) and 2 (1.33) rather than Cresswell and Paydar (1996) method.

Ghanbarian-Alavijeh, B.; Liaghat, A. M.; Huang, G.

2009-04-01

396

Evaluation of Point of Use Water Treatment Devices for Removal of Mine Wastes from Well Water  

EPA Science Inventory

U.S. EPA Region VII and the Office of Research and Development (ORD) are conducting a large-scale study to identify the prevalence of lead (Pb) and other contaminants in drinking water at four mine waste areas in Washington County, Missouri. Numerous households in Potosi, Richwoo...

397

[Effects of near-surface soil water conditions on agricultural non-point source pollutant transport].  

PubMed

Agricultural non-point source pollution is one of severe problems for water environment of agricultural area in China. The effects of near-surface soil water conditions on agricultural non-point source pollutant (AGNSP) transport during soil erosion processes, especially antecedent soil moisture was saturated, was developed by using artificial simulation rainfall experiment. The results showed that antecedent soil water content had great impact on AGNSP transport during soil erosive processes. Under the same soil texture, the AGNSP concentration and loading with runoff and sediment when the antecedent soil water content was saturated were greater than that of soil moisture un-saturated condition, and they would be increased as antecedent soil moisture increased. The approach of soil nitrogen loss was rainfall runoff; nitrogen loss with runoff was about 90.4% to 99.8% of total loss. The approaches of soil phosphorus were runoff and soil loss (sediment), the loss with runoff was about 2.67% to 23.5%, and the loss with sediment was about 76.5% to 97.3%. Soil texture had great influence on soil phosphorus loss; the concentration and loading of dissolved phosphorus (DP) with sediment from Yangling Loutu were greater than that of Ansai Loess. Some pertinence suggestions were given to control agricultural non-point source pollution, such as the best management practices. PMID:19402484

Zhang, Yu-Bin; Zheng, Fen-Li; Cao, Ning

2009-02-15

398

Probability of freezing in the freeze-avoiding beetle larvae Cucujus clavipes puniceus (Coleoptera: Cucujidae) from interior Alaska.  

PubMed

Freeze-avoiding insects must resist freezing or die. A suite of adaptations to low temperatures, including the production of antifreeze proteins, colligative antifreezes (polyols), and dehydration allows most individuals to prevent freezing below the lowest ambient temperatures experienced in situ; however, there can be a wide variance in the minimum temperatures that individuals of freeze-avoiding species reach before freezing. We used logistic regression to explore factors that affect this variance and to estimate the probability of freezing in larvae of the freeze-avoiding beetle Cucujus clavipes puniceus. We hypothesized that water content ?0.5 mg mg(-1) dry mass would lead to deep supercooling (avoidance of freezing below -58°C). We found a significant interaction between water content and ambient below-snow temperature and a significant difference between individuals collected from two locations in Alaska: Wiseman and Fairbanks. Individuals collected in Wiseman deep supercooled with greater water content and to a greater range of ambient temperatures than individuals collected in Fairbanks, leading to significantly different lethal water contents associated with 50% probability of freezing. PMID:21550349

Sformo, T; McIntyre, J; Walters, K R; Barnes, B M; Duman, J

2011-04-28

399

Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution.  

PubMed

The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely applicable to all countries in the warm and humid region of the world. PMID:11724486

Fujioka, R S

2001-01-01

400

Characteristics of the Self-evaporation Behavior of Sprinkled Water near the Triple Point  

NASA Astrophysics Data System (ADS)

For the sake of capturing the basic data in concern with the designing of vacuum evaporation apparatus, characteristics of the self-evaporation behavior of sprinkled water near the triple point has been investigated experimentally. The relationship between the amount of the vaporized water and the pressure in the vessel was elucidated quantitatively on the condition that over-heated water was sprinkled from water supplying nozzles of diameter of 4 mm into the center of the steam area in the heat insulation glass evaporation vessel having diameter of 200 mm and height of 1100 mm. Even under the mild water sprinkling conditions such as no small particle formation, small Reynolds number, and small Weber number, the temperature effectiveness of the self-evaporation in the center of the steam was as high as 80%, which clearly shows the effectiveness of this water-sprinkling method. In addition, the basic data for system designing such as water evaporation coefficient from water layer surface and temperature effectiveness of self-evaporation during the f1ight in the steam space were obtained.

Aizawa, Kazuo; Hayashi, Kanetoshi; Ogoshi, Hidemasa; Maeyama, Katsuya; Yonezawa, Noriyuki

401

Use of manometric temperature measurement (MTM) and SMART freeze dryer technology for development of an optimized freeze-drying cycle.  

PubMed

This report provides, for the first time, a summary of experiments using SMART Freeze Dryer technology during a 9 month testing period. A minimum ice sublimation area of about 300 cm(2) for the laboratory freeze dryer, with a chamber volume 107.5 L, was found consistent with data obtained during previous experiments with a smaller freeze dryer (52 L). Good reproducibility was found for cycle design with different type of excipients, formulations, and vials used. SMART primary drying end point estimates were accurate in the majority of the experiments, but showed an over prediction of primary cycle time when the product did not fully achieve steady state conditions before the first MTM measurement was performed. Product resistance data for 5% sucrose mixtures at varying fill depths were very reproducible. Product temperature determined by SMART was typically in good agreement with thermocouple data through about 50% of primary drying time, with significant deviations occurring near the end of primary drying, as expected, but showing a bias much earlier in primary drying for high solid content formulations (16.6% Pfizer product) and polyvinylpyrrolidone (40 kDa) likely due to water "re-adsorption" by the amorphous product during the MTM test. PMID:17853427

Gieseler, Henning; Kramer, Tony; Pikal, Michael J

2007-12-01

402

Measurement of evaporative water loss in small animals by dew-point hygrometry.  

PubMed

This paper presents the procedures and equations to be utilized for measurement of evaporative water loss (mw), by use of the dew-point hygrometer, in small animals exposed to air containing water vapor in an open-flow system. The system accounted accurately for the water evaporated from a bubble flask. In addition, hygrometric measurements of pulmocutaneous mw in pigeons (Columba livia, mean mass 0.31 kg) agreed closely with simultaneous gravimetric measurements, utilizing a desiccant in the sample stream, in a manner independently of air temperature (Ta, 20 or 40 degrees C), ambient water vapor pressure (PW, 4-16 10(2) Pa), or mw (5-66 mg-min-1). Evaporation in pigeons was independent of PW at 20 degrees C, but increased with decreasing PW at 40 degrees C, suggesting differences in ventilatory adjustments to changes in PW at the two temperatures. PMID:893300

Bernstein, M H; Hudson, D M; Stearns, J M; Hoyt, R W

1977-08-01

403

Boiling water with ice: Effect of pressure on the boiling point of water  

NSDL National Science Digital Library

This guided inquiry activity, in which ice is used to boil water in a Florence flask, works well in the introductory class to a chemistry or physical science course. The students will learn the difference between observation and inference and apply this understanding to various other situations in which observations and inferences must be made. The students will also use outside sources to try to explain why the activity worked.

404

Analysis of stresses during the freezing of solid spherical foods  

Microsoft Academic Search

An analytical model is presented to calculate thermal stresses and strains during the freezing of a spherical food, taking into account both the expansion during phase change and subsequent thermal contraction due to temperature decrease. The Young modulus and Poisson ratio are assumed to undergo a step change at the freezing point. The expansion due to phase change cause a

Q. Tuan Pham; Alain Le Bail; Brice Tremeac

2006-01-01

405

Screening and identification of early warning algal species for metal contamination in fresh water bodies polluted from point and non-point sources.  

PubMed

The water bodies of Lucknow, Unnao and Kanpur (U.P.), India polluted through various point and non point sources were found to be either eutrophic or oligotrophic in nature. These water bodies supported a great number of algal diversity, which varied seasonally depending upon the physico-chemical properties of water. Further, the water bodies polluted through non point sources supports diverse algal species, while the water bodies polluted through point sources supports growth of tolerant blue green algae. High biomass producing algal species growing in these water bodies have accumulated significant amount of metals in their tissues. Maximum amount of Fe was found accumulated by species of Oedogonium sp. II (20,523.00 microg g(-1) dw) and Spirogyra sp. I (4,520.00 microg g(-1) dw), while maximum Chromium (Cr) was found accumulated in Phormedium bohneri (2,109.00 microg g(-1) dw) followed by Oscillatoria nigra (1,957.88 microg g(-1) dw) and Oedogonium sp. I (156.00 microg g(-1) dw) and Ni in Ulothrix sp. (495.00 microg g(-1) dw). Results showed that some of these forms growing in polluted environment and accumulating high amounts of toxic metals may be used as bioindicator species, however, their performance in metal contaminated water under different ecological niche is to be ascertained. PMID:18071919

Rai, U N; Dubey, Smita; Shukla, O P; Dwivedi, S; Tripathi, R D

2007-12-11

406

A Process and Pilot Plant Design Study of the Absorption Freezing Vapor Compression Process.  

National Technical Information Service (NTIS)

A design study of the Absorption Freezing Vapor Compression (AFVC) process for desalination and other concentration/separation treatments of waste water was conducted. The AFVC process overcomes one of the major problem areas in previous freezing processe...

1977-01-01

407

Two-dimensional freezing criteria for crystallizing colloidal monolayers  

SciTech Connect

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.

Wang Ziren; Han Yilong [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong); Alsayed, Ahmed M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd St., Philadelphia, Pennsylvania 19104 (United States); Complex Assemblies of Soft Matter, CNRS/UPENN/Rhodia UMI 3254, Bristol, Pennsylvania 19007 (United States); Yodh, Arjun G. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd St., Philadelphia, Pennsylvania 19104 (United States)

2010-04-21

408

Pilot?scale Ultrasonic Assisted Cloud Point Extraction of Polycyclic Aromatic Hydrocarbons from Polluted Water  

Microsoft Academic Search

Cloud point extraction (CPE) has been proved to be an efficient and environment?friendly separation technology for polycyclic aromatic hydrocarbons from polluted water in many related researches. However, its traditional phase separation process, based on throughput?limited centrifugation or low?efficient heating, limited the scaling up and continuous operation of CPE process to a large extent. In our previous study, an efficient and

Bingjia Yao; Li Yang

2008-01-01

409

Point-of-use water disinfection using UV light-emitting diodes to reduce bacterial contamination.  

PubMed

The treatment process described in this research explores the impact of exposing water samples containing fecal coliforms to the radiation produced by single ultraviolet (UV) light-emitting diodes (LEDs) operating at 265 nm. UV LEDs are long lasting, compact in size and produce more efficient light output than traditional mercury-vapour bulbs, making them ideal for application in point-of-use disinfection systems, such as in remote areas. In this study, contaminated water samples containing either a pure culture of Escherichia coli or tertiary effluent from the City of Regina Wastewater Treatment Plant were used to study the application and efficiency of using UV LEDs for water disinfection. The results indicate that bacterial inactivation was achieved in a time-dependent manner, with 1- and 2.5-log E. coli reductions in water following 20 and 50 min of UV LED exposure, respectively. Ultraviolet radiation was less effective in reducing coliform bacteria in wastewater samples due to the elevated turbidity levels. Further work remains to be completed to optimize the application of UV LEDs for point-of-use disinfection systems; however, the results from this study support that bacterial inactivation using UV LEDs is possible, meriting further future technological development of the LEDs. PMID:23423870

Nelson, Kristina Y; McMartin, Dena W; Yost, Christopher K; Runtz, Ken J; Ono, Takaya

2013-02-20

410

Assessment of ground-water contamination in the alluvial aquifer near West Point, Kentucky  

USGS Publications Warehouse

Well inventories, water level measurements, groundwater quality samples, surface geophysical techniques (specifically, electromagnetic techniques), and test drilling were used to investigate the extent and sources of groundwater contamination in the alluvial aquifer near West Point, Kentucky. This aquifer serves as the principal source of drinking water for over 50,000 people. Groundwater flow in the alluvial aquifer is generally unconfined and moves in a northerly direction toward the Ohio River. Two large public supply well fields and numerous domestic wells are located in this natural flow path. High concentrations of chloride in groundwater have resulted in the abandonment of several public supply wells in the West Point areas. Chloride concentrations in water samples collected for this study were as high as 11,000 mg/L. Electromagnetic techniques indicated and test drilling later confirmed that the source of chloride in well waters was probably improperly plugged or unplugged, abandoned oil and gas exploration wells. The potential for chloride contamination of wells exists in the study area and is related to proximity to improperly abandoned oil and gas exploration wells and to gradients established by drawdowns associated with pumped wells. Periodic use of surface geophysical methods, in combination with added observation wells , could be used to monitor significant changes in groundwater quality related to chloride contamination. (USGS)

Lyverse, M. A.; Unthank, M. D.

1988-01-01

411

To freeze or not to freeze: adaptations for overwintering by hatchlings of the North American painted turtle.  

PubMed

Many physiologists believe that hatchling painted turtles (Chrysemys picta) provide a remarkable, and possibly unique, example of 'natural freeze-tolerance' in an amniotic vertebrate. However, the concept of natural freeze-tolerance in neonatal painted turtles is based on results from laboratory studies that were not placed in an appropriate ecological context, so the concept is suspect. Indeed, the weight of current evidence indicates that hatchlings overwintering in the field typically withstand exposure to ice and cold by avoiding freezing altogether and that they do so without benefit of an antifreeze to depress the equilibrium freezing point for bodily fluids. As autumn turns to winter, turtles remove active nucleating agents from bodily fluids (including bladder and gut), and their integument becomes a highly efficient barrier to the penetration of ice into body compartments from frozen soil. In the absence of a nucleating agent or a crystal of ice to 'catalyze' the transformation of water from liquid to solid, the bodily fluids remain in a supercooled, liquid state. The supercooled animals nonetheless face physiological challenges, most notably an increased reliance on anaerobic metabolism as the circulatory system first is inhibited and then caused to shut down by declining temperature. Alterations in acid/base status resulting from the accumulation of lactic acid may limit survival by supercooled turtles, and sublethal accumulations of lactate may affect behavior of turtles after the ground thaws in the spring. The interactions among temperature, circulatory function, metabolism (both aerobic and anaerobic), acid/base balance and behavior are fertile areas for future research on hatchlings of this model species. PMID:15277545

Packard, Gary C; Packard, Mary J

2004-08-01

412

On the realism of the re-engineered simple point charge water model  

SciTech Connect

The realism of the recently proposed high-temperature reparameterization of the simple point charge (SPC) water model [C. D. Berweger, W. F. van Gunsteren, and F. M{umlt u}ller-Plathe, Chem. Phys. Lett. {bold 232}, 429 (1995)] is tested by comparing the simulated microstructure and dielectric properties to the available experimental data. The test indicates that the new parameterization fails dramatically to describe the microstructural and dielectric properties of water at high temperature; it predicts rather strong short-range site{endash}site pair correlations, even stronger than those for water at ambient conditions, and a threefold smaller dielectric constant. Moreover, the resulting microstructure suggests that the high-temperature force-field parameters would predict a twofold higher critical density. The failure of the high-temperature parameterization is analyzed and some suggestions on alternative choices of the target properties for the weak-coupling are discussed. {copyright} {ital 1996 American Institute of Physics.}

Chialvo, A.A. [Department of Chemical Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200 (United States)]|[Chemical Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6268 (United States)

1996-04-01

413

Ab initio calculation of solvation energies for chemical reactions in water near its critical point  

NASA Astrophysics Data System (ADS)

In this talk, we revisit Kirkwood's original formulation of solvation energies in water(J.G. Kirkwood, J. Chem. Phys.) 2(7), 351 (1934). in the context of modern ab initio electronic structure techniques. In order to explain the observed strong non-Arrhenius behavior of the hydrolysis of methylene chloride (CH_2Cl_2) near the critical point of water, we use ab initio calculations to determine molecular charge distributions and the appropriate form for a continuum dielectric model of the surrounding water medium as the reaction proceeds. We then compute the solvation energy along the reaction profile by solving the Poisson-Boltzmann equation numerically without simplifications. The results show remarkable quantitative agreement with Kirkwood's original model of a molecular dipole in a spherical dielectric cavity, even for transition-state complexes of highly non-spherical shape and complex charge distribution. We will discuss the reason for this unexpected correlation and the implication of our results for this reaction.

Ismail-Beigi, Sohrab; Marrone, P. A.; Arias, T. A.

1998-03-01

414

Swash-aquifer interaction in the vicinity of the water table exit point on a sandy beach  

Microsoft Academic Search

The coupling of sandy beach aquifers with the swash zone in the vicinity of the water table exit point is investigated through simultaneous measurements of the instantaneous shoreline (swash front) location, pore pressures and the water table exit point. The field observations reveal new insights into swash-aquifer coupling not previously gleaned from measurements of pore pressure only. In particular, for

Nick Cartwright; Tom E. Baldock; Peter Nielsen; Dong-Sheng Jeng; Longbin Tao

2006-01-01

415

Evaluating the Sustainability of Ceramic Filters for Point-of-Use Drinking Water Treatment.  

PubMed

This study evaluates the social, economic, and environmental sustainability of ceramic filters impregnated with silver nanoparticles for point-of-use (POU) drinking water treatment in developing countries. The functional unit for this analysis was the amount of water consumed by a typical household over ten years (37,960 L), as delivered by either the POU technology or a centralized water treatment and distribution system. Results indicate that the ceramic filters are 3-6 times more cost-effective than the centralized water system for reduction of waterborne diarrheal illness among the general population and children under five. The ceramic filters also exhibit better environmental performance for four of five evaluated life cycle impacts: energy use, water use, global warming potential, and particulate matter emissions (PM10). For smog formation potential, the centralized system is preferable to the ceramic filter POU technology. This convergence of social, economic, and environmental criteria offers clear indication that the ceramic filter POU technology is a more sustainable choice for drinking water treatment in developing countries than the centralized treatment systems that have been widely adopted in industrialized countries. PMID:23991752

Ren, Dianjun; Colosi, Lisa M; Smith, James A

2013-09-18

416

On the size dependence of contact freezing probability  

NASA Astrophysics Data System (ADS)

The contact freezing of supercooled water droplets electrodynamically levitated in the aerosol flow containing clay mineral particles has been investigated in the temperature range from -27°C to -34°C. The aerosol generation system employs a multistage impactor to narrow down the size distribution of aerosol. We use mobility selected illite clay mineral particles of four characteristic diameters to investigate the influence of particle size onto the freezing probability in the contact mode. Our preliminary results show that the contact freezing probability is proportional to the square of particle size (surface area), a feature which is normally attributed to the immersion freezing efficacy of atmospheric ice active particles. Along with the observed temperature and material dependence of contact freezing, this finding provides a new basis for approaching the question of similarity between the contact and immersion freezing.

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

2013-05-01

417

Stabilization of Lipid Bilayer Vesicles by Sucrose during Freezing  

Microsoft Academic Search

The freeze-induced fusion and leakage of small unilamellar vesicles (SUV) of natural and synthetic phosphatidylcholines and the suppression of these processes by sucrose was studied by electron microscopy, by high-resolution NMR, and by ESR techniques. During slow freezing of SUV suspensions in water, the lipid was compressed into a small interstitial volume and transformed into a multilamellar aggregate without vesicular

G. Strauss; H. Hauser

1986-01-01

418

Freezing-Thawing Processes in Glass Fiber Board  

Microsoft Academic Search

For the prevention of vapor condensation and accompanying damage in cold regions, the behavior of water and ice in porous materials should be understood. In this study, experiments on the freezing-thawing processes in a glass fiber board, which is a typical insu lation, were conducted. The freezing-thawing processes were analyzed with the use of si multaneous heat and moisture transfer

S. Hokoi; M. Hatano; M. Matsumoto; M. K. Kumaran

2000-01-01

419

Two features at the two-dimensional freezing transitions.  

PubMed

We studied the two-dimensional freezing transitions in monolayers of microgel colloidal spheres with short-ranged repulsions in video-microscopy experiments, and monolayers of hard disks, and Yukawa particles in simulations. These systems share two common features at the freezing points: (1) the bimodal distribution profile of the local orientational order parameter; (2) the two-body excess entropy, s(2), reaches -4.5±0.5?k(B). Both features are robust and sensitive to the freezing points, so that they can potentially serve as empirical freezing criteria in two dimensions. Compared with the conventional freezing criteria, the first feature has no finite-size ambiguities and can be resolved adequately with much less statistics; and the second feature can be directly measured in macroscopic experiments without the need for microscopic information. PMID:21261367

Wang, Ziren; Qi, Weikai; Peng, Yi; Alsayed, Ahmed M; Chen, Yong; Tong, Penger; Han, Yilong

2011-01-21

420

Experimental quantification of contact freezing in an electrodynamic balance  

NASA Astrophysics Data System (ADS)

Heterogeneous nucleation of ice in a supercooled water droplet induced by external contact with a dry aerosol particle has long been known to be more effective than freezing induced by the same nucleus immersed in the droplet. However, the experimental quantification of contact freezing is challenging. Here we report an experimental method to determine the temperature-dependent ice nucleation probability of size-selected aerosol particles. The method is based on the suspension of supercooled charged water droplets in a laminar flow of air containing aerosol particles as contact freezing nuclei. The rate of droplet-particle collisions is calculated numerically with account for Coulomb attraction, drag force and induced dipole interaction between charged droplet and aerosol particles. The calculation is verified by direct counting of aerosol particles collected by a levitated droplet. By repeating the experiment on individual droplets for a sufficient number of times, we are able to reproduce the statistical freezing behavior of a large ensemble of supercooled droplets and measure the average rate of freezing events. The freezing rate is equal to the product of the droplet-particle collision rate and the probability of freezing on a single contact, the latter being a function of temperature, size and composition of the contact ice nuclei. Based on these observations, we show that for the types of particles investigated so far, contact freezing is the dominating freezing mechanism on the timescale of our experiment.

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

2013-09-01

421

Ice/Water Interface: Zeta Potential, Point of Zero Charge, and Hydrophobicity.  

PubMed

The ice/water interface is a common and important part of many biological, environmental, and technological systems. In contrast to its importance, the system has not been extensively studied and is not well understood. Therefore, in this paper the properties of the H(2)O ice/water and D(2)O ice/water interfaces were investigated. Although the zeta potential vs pH data points were significantly scattered, it was determined that the isoelectric point (iep) of D(2)O ice particles in water at 3.5 degrees C containing 10(-3) M NaCl occurs at about pH 3.0. The negative values of the zeta potential, calculated from the electrophoretic mobility, seem to decrease with decreasing content of NaCl, while the iep shifts to a higher pH. The point of zero charge (pzc) of D(2)O ice and H(2)O ice, determined by changes in pH of 10(-4) M NaCl aqueous solution at 0.5 degrees C after the ice particle addition, was found to be very different from the iep and equal to pH 7.0 +/- 0.5. The shift of the iep with NaCl concentration and the difference in the positions of the iep and pzc on the pH scale point to complex specific adsorption of ions at the interface. Interestingly, similar values of iep and pzc were found for very different systems, such as hydrophilic ice and highly hydrophobic hexadecane droplets in water. A comparison of the zeta potential vs pH curves for hydrophilic ice and hydrophobic materials that do not possess dissociative functional groups at the interface (diamond, air bubbles, bacteria, and hexadecane) indicated that all of them have an iep near pH 3.5. These results indicate that the zeta potential and surface charge data alone cannot be used to delineate the electrochemical properties of a given water/moiety interface because similar electrical properties do not necessary mean a similar structure of the interfacial region. A good example is the aliphatic hydrocarbon/water interface in comparison to the ice/water interface. Although the experiments were carried out with care, both the zeta potential, measured with a precise ZetaPlus meter, and DeltapH values (a measure of surface charge) vs pH were significantly scattered, and the origin of dissemination of the data points was not established. Differently charged ice particles and not fully equilibrium conditions at the ice/water interface may have been responsible for the dissemination of the data. Copyright 1999 Academic Press. PMID:10607438

Drzymala; Sadowski; Holysz; Chibowski

1999-12-15

422

Magnetic resonance tells microbiology where to go; bacterial teichoic acid protects liquid water at sub-zero temperatures  

Microsoft Academic Search

Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, although, with a few exceptions, antifreeze proteins are missing. Survival has been

Charles V. Rice; Jason R. Wickham; Margaret A. Eastman; William Harrison; Mark P. Pereira; Eric D. Brown

2008-01-01

423

Proposal on a sustainable strategy to avoid point source pollution of water with plant protection products.  

PubMed

Based on the results and lessons learned from the TOPPS project (Training the Operators to prevent Pollution from Point Sources), a proposal on a sustainable strategy to avoid point source pollution from Plant Protection Products (PPPs) was made. Within this TOPPS project (2005-2008), stakeholders were interviewed and research and analysis were done in 6 pilot catchment areas (BE, FR, DE, DK, IT, PL). Next, there was a repeated survey on operators' perception and opinion to measure changes resulting from TOPPS activities and good and bad practices were defined based on the Best Management Practices (risk analysis). Aim of the proposal is to suggest a strategy considering the differences between countries which can be implemented on Member State level in order to avoid PPP pollution of water through point sources. The methodology used for the up-scaLing proposal consists of the analysis of the current situation, a gap analysis, a consistency analysis and organisational structures for implementation. The up-scaling proposal focuses on the behaviour of the operators, on the equipment and infrastructure available with the operators. The proposal defines implementation structures to support correct behaviour through the development and updating of Best Management Practices (BMPs) and through the transfer and the implementation of these BMPs. Next, the proposal also defines requirements for the improvement of equipment and infrastructure based on the defined key factors related to point source pollution. It also contains cost estimates for technical and infrastructure upgrades to comply with BMPs. PMID:20218516

Mestdagh, Inge; Bonicelli, Bernard; Laplana, Ramon; Roettele, Manfred

2009-01-01

424

Ultrasound-Assisted Freezing  

NASA Astrophysics Data System (ADS)

Freezing is a well-known preservation method widely used in the food industry. The advantages of freezing are to a certain degree counterbalanced by the risk of damage caused by the formation and size of ice crystals. Over recent years new approaches have been developed to improve and control the crystallization process, and among these approaches sonocrystallization has proved to be very useful, since it can enhance both the nucleation rate and the crystal growth rate. Although ultrasound has been successfully used for many years in the evaluation of various aspects of foods and in medical applications, the use of power ultrasound to directly improve processes and products is less popular in food manufacturing. Foodstuffs are very complex materials, and research is needed in order to define the specific sound parameters that aid the freezing process and that can later be used for the scale-up and production of commercial frozen food products.

Delgado, A. E.; Sun, Da-Wen

425

Heterogeneous freezing of ammonium sulfate and sodium chloride solutions by long chain alcohols  

NASA Astrophysics Data System (ADS)

High molecular weight organic compounds emitted during biomass burning can be transported to high altitudes where they may affect ice processes through heterogeneous nucleation. We show that freezing of solutions of ammonium sulfate and sodium chloride catalyzed by long chain alcohols is roughly consistent with the hypothesis that the water activity at the mean freezing temperature is a constant offset from the water activity at the melting point of the solution, though films of the longer chain alcohols may undergo structural changes at higher salt concentrations which cause a deviation from the constant offset. The heterogeneous nucleation rate coefficient, averaged over all solutions, alcohols, and droplet sizes is 6.0 × 104 +/- 4.0 × 104 cm-2 s-1, with no dependence on any of those parameters.

Cantrell, Will; Robinson, Carly

2006-04-01

426

Scaling-Up Eutectic Freeze Crystallization  

Microsoft Academic Search

A novel crystallization technology, Eutectic Freeze Crystallization (EFC) has been investigated and further developed in this thesis work. EFC operates around the eutectic temperature and composition of aqueous solutions and can be used for recovery of (valuable) dissolved salts (and\\/or or acids) and water from a wide variety of aqueous process streams. Using EFC, processes producing large quantities of saline

F. E. Genceli

2008-01-01

427

Bk060042 Cell Freeze Liquid Nitrogen Freezing Container  

Center for Biologics Evaluation and Research (CBER)

Text Version... NC 21103 Telephone 336 168-6447 F;Jcsirnile 336 774-1150 510(k) Summary Charter Medical Cell Freeze™ Liquid Nitrogen Freezing Container ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

428

Effects of different methods of preparation of ice mantles of triple point of water cells on the temporal behaviour of the triple-point temperatures  

Microsoft Academic Search

We report results of an investigation of the temporal variation of the temperature of triple point of water (TPW) cells, in which the ice mantles were prepared by four different techniques using: (i) solid CO2, (ii) an immersion cooler, (iii) liquid-nitrogen-cooled rods, and (iv) liquid nitrogen (LN), first passing cold nitrogen vapours and then LN directly into the wells of

G T Furukawa; B W Mangum; G F Strouse

1997-01-01

429

Effects of different Methods of Preparation of Ice Mantles of Triple Point of Water Cells on the Temporal Behaviour of the Triple-Point Temperatures.  

National Technical Information Service (NTIS)

We report results of an investigation of the temporal variation of the temperature of triple point of water (TPW) cells, in which the ice mantles were prepared by four different techniques using: (1) solid carbon dioxide, (2) an immersion cooler, (3) liqu...

B. W. Mangum G. F. Strouse G. T. Furukawa

2008-01-01

430

Flame atomic absorption determination of manganese(II) in natural water after cloud point extraction  

Microsoft Academic Search

The possibility to use 4-(2-pyridylazo)resorcinol (PAR) and 1-(2-pyridylazo)-2-naphthol (PAN) for manganese(II) concentrating by the micellar extraction at cloud point (CP) temperature and subsequent atomic absorption spectrometry (AAS) determination was investigated. Under the optimum conditions, preconcentration of 100ml of water sample in the presence of 1% non-ionic surfactant (NS) OP-7, 1×10?4M 1-(2-pyridylazo)-2-naphthol permitted the detection 5?gl?1 manganese. The proposed method has

V. O. Doroschuk; S. O. Lelyushok; V. B. Ishchenko; S. A. Kulichenko

2004-01-01

431

Novel Spray Freeze-Drying Technique Using Four-Fluid Nozzle—Development of Organic Solvent System to Expand Its Application to Poorly Water Soluble Drugs  

Microsoft Academic Search

Spray freeze-drying (SFD) technique using four-fluid nozzle (4N), which is a novel particle design technique previously developed by authors, has been further developed to expand its application in pharmaceutical indus- try. The organic solvent was utilized as a spray solvent to dissolve the poorly soluble drug instead of conventional aqueous solution. Acetonitrile solution of the drug and aqueous solution of

Toshiyuki Niwa; Hiroko Shimabara; Kazumi Danjo

2010-01-01

432

The North Cape oil spill: hydrocarbons in Rhode Island coastal waters and Point Judith Pond.  

PubMed

On 19 January 1996, the North Cape oil barge ran aground near Moonstone Beach, RI, and spilled over 2700 metric tons of No. 2 fuel oil during a severe winter storm. High winds and rough seas drove the oil into the water column, and the oil spread throughout Block Island Sound and into several coastal salt ponds. Over 50 water samples were collected from Point Judith Pond (PJP) and the southern coast of Rhode Island for four months after the spill and analyzed for polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs). These analyses revealed that at least 60 km2 of coastal waters were impacted from the spill. Maximum concentrations of sigmaPAHs and TPHs were 115 and 3940 microg l(-1), respectively. The percentage of sigmaPAHs relative to the TPHs for all samples varied from 0.2 to 43%, showing that there was no clear relationship between sigmaPAHs and TPHs for the whole dataset and likely resulting from spatial and temporal partitioning over the course of the spill. However, within the dataset, there were stronger correlations for distinct samples collected at similar locations and times. In PJP, water column concentrations of individual PAHs decreased at rates of 0.08-0.24 day(-1) and lower-molecular weight PAHs were removed faster than higher-molecular weight PAHs. PMID:11763148

Reddy, C M; Quinn, J G

2001-12-01

433

Freezing Effects on Aggregate Stability Affected by Texture, Mineralogy, and Organic Matter  

Microsoft Academic Search

Aggregate stability, an important property influencing a soil's re- sponse to erosive forces, is affected by freezing. The objectives of this laboratory study were to determine how constrainment, number of freeze-thaw cycles, and water content at freezing affect the ag- gregate stability of six continental USA soils differing in texture, mineralogy, and organic-matter content. Moist aggregates, after being frozen and

G. A. Lehrsch; R. E. Sojka; D. L. Carter; P. M. Jolley

1991-01-01

434

SOIL TEMPERATURE AND FALL FREEZE-THAW EFFECTS ON INFILTRATION AND SOIL MOISTURE MOVEMENT  

Microsoft Academic Search

The quantity of spring snowmelt infiltration and runoff depends on the antecedent soil moisture conditions at the time of soil freezing. Determining the soil moisture status at any particular time during the freezing process requires an understanding of vertical distribution of liquid and frozen water content within the soil profile. This study investigated the effects of soil freezing and thawing

F. C. Kahimba

2006-01-01

435

Deliquesence and freezing of stratospheric aerosol observed by balloonborne backscattersondes  

SciTech Connect

Stratospheric sulfate aerosols, originating from the Mt. Pinatubo volcanic eruption, have been observed during three winters in the Arctic by balloonborne backscattersondes. A measured color index, defined as the quotient between the aerosol backscatter ratios at wavelengths 940 and 480 nm, provides information of the size of the observed particles. The effects of liquid particle growth, by water vapor uptake, clearly show up as changes in the color index, whereas measurements on other days indicate the particles to be frozen. Air parcel trajectories have been calculated, providing the temperature history of the observed particles. Evidences appear of a temperature hysteresis in the freezing and melting cycle of the aerosol, indicating melting temperatures around 215-220 K in good agreement with laboratory measurements, and freezing of the particles within less than 5 K above the ice frost point. The changes in color index of the liquid particles are in good agreement with predictions from theoretical model calculations of growth by water vapor uptake. 13 refs., 5 figs., 1 tab.

Larsen, N.; Knudsen, B. [Danish Meterological Institute, Copenhagen (Denmark); Rosen, J.M. [Univ. of Wyoming, Laramie, WY (United States)] [and others

1995-05-15

436

CryoMACS Freezing Bag  

Center for Biologics Evaluation and Research (CBER)

... CryoMACS Freezing Bag. Applicant: Miltenyi Biotec, Incorporated. 510(k) number: BK090020. Product: CryoMACS Freezing Bag. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

437

Tracing cytoplasmic Ca(2+) ion and water access points in the Ca(2+)-ATPase.  

PubMed

Sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) transports two Ca(2+) ions across the membrane of the sarco(endo)plasmic reticulum against the concentration gradient, harvesting the required energy by hydrolyzing one ATP molecule during each transport cycle. Although SERCA is one of the best structurally characterized membrane transporters, it is still largely unknown how the transported Ca(2+) ions reach their transmembrane binding sites in SERCA from the cytoplasmic side. Here, we performed extended all-atom molecular dynamics simulations of SERCA. The calculated electrostatic potential of the protein reveals a putative mechanism by which cations may be attracted to and bind to the Ca(2+)-free state of the transporter. Additional molecular dynamics simulations performed on a Ca(2+)-bound state of SERCA reveal a water-filled pathway that may be used by the Ca(2+) ions to reach their buried binding sites from the cytoplasm. Finally, several residues that are involved in attracting and guiding the cations toward the possible entry channel are identified. The results point to a single Ca(2+) entry site close to the kinked part of the first transmembrane helix, in a region loaded with negatively charged residues. From this point, a water pathway outlines a putative Ca(2+) translocation pathway toward the transmembrane ion-binding sites. PMID:22339863

Musgaard, Maria; Thøgersen, Lea; Schiøtt, Birgit; Tajkhorshid, Emad

2012-01-18

438

Modeling soil freezing dynamics  

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...

439

Animal Anti-Freeze  

NSDL National Science Digital Library

In this outdoor winter activity, learners search for and create hibernation sites that will protect gelatin "animals" from freezing. Learners come to understand that hibernating animals need to take care in selecting a sleeping spot that will provide protection from the winter cold.

Science, Lawrence H.

1982-01-01

440

Freezing human ES cells.  

PubMed

Here we demonstrate how our lab freezes HuES human embryonic stem cell lines. A healthy, exponentially expanding culture is washed with PBS to remove residual media that could otherwise quench the Trypsin reaction. Warmed 0.05% Trypsin-EDTA is then added to cover the cells, and the plate allowed to incubate for up to 5 mins at room temperature. During this time cells can be observed rounding, and colonies lifting off the plate surface. Gentle repeated pipetting will remove cells and colonies from the plate surface. Trypsinized cells are placed in a standard conical tube containing pre-warmed hES cell media to quench remaining trypsin, and then spun. Cells are resuspended growth media at a concentration of approximately one million cells in one mL of media, a concentration such that one frozen aliquot is sufficient to resurrect a culture on a 10 cm plate. After cells are adequately resuspended, ice cold freezing media is added at equal volume. Cell suspensions are mixed thoroughly, aliquoted into freezing vials, and allowed to slowly freeze to -80 C over 24 hours. Frozen cells can then moved to the vapor phase of liquid nitrogen for long term storage, or remain at -80 for approximately six months. PMID:18704182

Trish, Erin; Dimos, John; Eggan, Kevin

2006-10-12

441

Embolism formation during freezing in the wood of Picea abies.  

PubMed

Freeze-thaw events can cause embolism in plant xylem. According to classical theory, gas bubbles are formed during freezing and expand during thawing. Conifers have proved to be very resistant to freeze-thaw induced embolism, because bubbles in tracheids are small and redissolve during thawing. In contrast, increasing embolism rates upon consecutive freeze-thaw events were observed that cannot be explained by the classical mechanism. In this study, embolism formation during freeze-thaw events was analyzed via ultrasonic and Cryo-scanning electron microscope techniques. Twigs of Picea abies L. Karst. were subjected to up to 120 freeze-thaw cycles during which ultrasonic acoustic emissions, xylem temperature, and diameter variations were registered. In addition, the extent and cross-sectional pattern of embolism were analyzed with staining experiments and Cryo-scanning electron microscope observations. Embolism increased with the number of freeze-thaw events in twigs previously dehydrated to a water potential of -2.8 MPa. In these twigs, acoustic emissions were registered, while saturated twigs showed low, and totally dehydrated twigs showed no, acoustic activity. Acoustic emissions were detected only during the freezing process. This means that embolism was formed during freezing, which is in contradiction to the classical theory of freeze-thaw induced embolism. The clustered pattern of embolized tracheids in cross sections indicates that air spread from a dysfunctional tracheid to adjacent functional ones. We hypothesize that the low water potential of the growing ice front led to a decrease of the potential in nearby tracheids. This may result in freezing-induced air seeding. PMID:17041033

Mayr, Stefan; Cochard, Hervé; Améglio, Thierry; Kikuta, Silvia B

2006-10-13

442

Freezing survival, body ice content and blood composition of the freeze-tolerant European common lizard, Lacerta vivipara.  

PubMed

To investigate the freeze tolerance of the European common lizard, Lacerta vivipara, we froze 17 individuals to body temperatures as low as -4 degrees C under controlled laboratory conditions. The data show that this species tolerates the freezing of 50% of total body water and can survive freezing exposures of at least 24-h duration. Currently, this represents the best known development of freeze tolerance among squamate reptiles. Freezing stimulated a significant increase in blood glucose levels (16.15+/- 1.73 micromol x ml(-1) for controls versus 25.06 +/- 2.92 micromol x ml(-1) after thawing) but this increase had no significant effect on serum osmolality which was unchanged between control and freeze-exposed lizards (506.0 +/- 23.8 mosmol x l(-1) versus 501.0 +/- 25.3 mosmol x l(-1), respectively). Tests that assessed the possible presence of antifreeze proteins in lizard blood were negative. Recovery at 5 degrees C after freezing was assessed by measurements of the mean time for the return of breathing (5.9 +/- 0.5 h) and of the righting reflex (44.8 +/- 4.5 h). Because this species hibernates in wet substrates inoculative freezing may frequently occur in nature and the substantial freeze tolerance of this lizard should play a key role in its winter survival. PMID:11824405

Voituron, Y; Storey, J M; Grenot, C; Storey, K B

2002-01-01

443

Effect of long-term freezing and freeze-thaw cycles on indigenous and inoculated microorganisms in dewatered blackwater.  

PubMed

Wastewater treatment in many Arctic regions is inadequate, even nonexisting. Natural freezing of wastewater in those areas may be beneficial for reduction of microorganisms. The aim of this study was to investigate the effect of long-term freezing, and repeated freezing and thawing, on indigenous coliforms, fecal streptococci, and antibiotic-resistant (AR) bacteria, and inoculated Salmonella Enteriditis and E. coli bacteriophage ?X174 in dewatered blackwater. At the end of the long-term freezing experiment (10 months), an MPN recovery study was done, including the microbial groups that had shown the largest reduction, using tryptone soy broth at incubation temperatures of 10 and 20 °C overnight for the coliforms and AR bacteria, and buffered peptone water at incubation temperature of 37 °C for 18-20 h for Salmonella. Fecal streptococci were more resistant to long-term freezing than the coliform group. Total number of AR bacteria decreased slowly but constantly over the 10-month freezing period. Salmonella rapidly decreased and were nondetectable within a week but exhibited some recovery after 10 months of freezing, whereas limited or no recovery of coliforms and AR-bacteria was detected. Bacteriophages showed limited reduction during the long-term freezing. Repeated freezing and thawing increased the reduction of all tested microbial groups markedly. PMID:23113759

Gunnarsdóttir, Ragnhildur; Müller, Karoline; Jensen, Pernille Erland; Jenssen, Petter Deinboll; Villumsen, Arne

2012-11-05

444

Household drinking water in developing countries: a systematic review of microbiological contamination between source and point-of-use  

Microsoft Academic Search

Summary objective To assess the extent and causes of microbiological contamination of household drinking water between source and point-of-use in developing countries. methods A systematic meta-analysis of 57 studies measuring bacteria counts for source water and stored water in the home to assess how contamination varied between settings. results The bacteriological quality of drinking water significantly declines after collection in

Jim Wright; Stephen Gundry; Ronan Conroy

2004-01-01

445

Fate of Arsenic at a Landfill Plume Discharge Point Into Surface Water, Central Massachusetts  

NASA Astrophysics Data System (ADS)

Fate of dissolved arsenic in ground water at the point of discharge into surface water raises a concern about the public health and the environment due to a potential of arsenic accumulation in the bottom sediments. Dissolved arsenic may become sorbed on amorphous precipitates of ferric hydroxides formed by a changing redox potential during the discharge and then locally deposited. Many landfill plumes and natural reducing ground waters in Central Massachusetts have dissolved arsenic well above the EPA 10 ? g/L MCL level that could cause a local arsenic accumulation. The area of this study stretches along several man-made ponds in North Central Massachusetts located down gradient from (1) a landfill plume in which dissolved arsenic ranges between 50 and 700 ? g/L occasionally up to 5,000 ? g/L; (2) reduced natural ground water where dissolved arsenic can be as high as 200 ? g/L; and (3) oxygenated natural ground water with dissolved arsenic levels below 10 ? g/L. Bottom sediments were collected at 34 separate sites and additional samples were obtained from two to three foot cores at a subset of 9 sites. All samples were analyzed for extractable As, Fe, Ni, and other metals. Samples of bottom sediments near a discharge of the landfill plume form a layer highly enriched in Fe and As. Iron approaches the composition of 100% ferric hydroxides (390,000 and 420,000 mg/kg of Fe respectively). Corresponding arsenic values are 6,800 and 3,900 mg/kg which are nearly 100x the typical background values of arsenic in soils in this area. Arsenic concentrations in other sediments of the landfill plume area have a range from 220 to 2,000 mg/kg. Depth gradients from core sections indicate a decreasing As and Fe trend, yet significantly elevated arsenic levels are still detected at 2 ft depth (30 to 1,200 mg/kg of As). Sediments from the area where a reducing natural water mixes with the surface water have arsenic values that are 3 to 5 times the background soils (As range in the sediments: 66 to 140 mg/kg); no arsenic was detected at 2 ft depth (typical detection limit between 10 and 20 mg/kg). Sediments from the discharge area of oxygenated ground water have arsenic values indistinguishable from the background soils.

Brandon, W. C.; Hon, R.

2004-12-01

446

Phase diagram for freeze-dried persimmon  

Microsoft Academic Search

Phase transitions of freeze-dried persimmon in a large range of moisture content were determined by differential scanning calorimetry (DSC). In order to study this transitions at low and intermediate moisture content domains, samples were conditioned by adsorption at various water activities (aw=0.11–0.90) at 25°C. For the high moisture content region, samples were obtained by water addition. At aw?0.75 two glass

P. J. A. Sobral; V. R. N. Telis; A. M. Q. B. Habitante; A. Sereno

2001-01-01

447

Freezing Potential of Electrolytic Solutions  

Microsoft Academic Search

The freezing potential for NH3 and NaCl solutions is studied with the experiments being performed at approximately constant freezing rates. The results permit discussion of the transitory and stationary features of the phenomenon. For NH4 solutions, the stationary freezing potential is studied as a function of the growth rate and of the concentration of the solutions. Measurements were also made

Laura Levi; Oscar Milman

1966-01-01

448

Twin Rinse Columns for Freeze Concentration of Rinsable Concentrates.  

National Technical Information Service (NTIS)

The apparatus of the invention was designed for the freeze concentration of liquids, removing pure water therefrom in frozen form and thereby making the liquid more concentrated. While not being limited thereto, the device is especially suited to the conc...

W. K. Heiland E. R. Radewonuk

1990-01-01

449

A diffusive anomaly of water in aqueous sodium chloride solutions at low temperatures.  

PubMed

Molecular dynamics simulations are presented for the self-diffusion coefficient of water in aqueous sodium chloride solutions. At temperatures above the freezing point of pure water, the self-diffusion coefficient is a monotonically decreasing function of salt concentration. Below the freezing point of pure water, however, the self-diffusion coefficient is a non-monotonic function of salt concentration, showing a maximum at approximately one molal salt. This suggests that sodium chloride, which is considered a structure-making salt at room temperature, becomes a structure-breaking salt at low temperatures. A qualitative understanding of this effect can be obtained by considering the effect of ions on the residence time of water molecules near other water molecules. A consideration of the freezing point depression of aqueous sodium chloride solutions suggests that the self-diffusion coefficient of water in supercooled sodium chloride solutions is always higher than that in pure (supercooled) water at the same temperature. PMID:18215033

Kim, Jun Soo; Yethiraj, Arun

2008-01-24

450

Natural freezing survival by painted turtles Chrysemys picta marginata and C. picta bellii.  

PubMed

Hatchlings of both the Midland (Chrysemys picta marginata) and Western (C. picta bellii) subspecies of the painted turtle tolerate the freezing of extracellular body fluids while overwintering in terrestrial nests. Fall-collected hatchlings survived 3 days of continuous freezing at -2.5 degrees C, with ice contents of 43.5 +/- 1.0% of total body water (SE; n = 24) for C. picta marginata and 46.5 +/- 0.8% (n = 32) for C. picta bellii. Survival times dropped to 4-5 h when temperature was lowered to -4 degrees C, correlated with ice contents of greater than or equal to 50%. However, C. picta marginata tested immediately after excavation from nests in the spring showed greater freeze tolerance, with survival extending to 11 days at -2.5 degrees C and a higher mean ice content of 50.2 +/- 1.2% (n = 6). Spring hatchlings also had high supercooling points, -1.07 +/- 0.13 degrees C (n = 8), that dropped within 3 days to -4.83 +/- 0.83 degrees C (n = 4), suggesting a breakdown of endogenous ice-nucleating agents when hibernation ended. A search for possible cryoprotectants showed that both subspecies accumulated glucose and lactate in liver during freezing (net increase = 3-13 mumols/g wet wt); both also maintained large free amino acid pools in organs, with taurine making up 21-47% of the total. PMID:1558223

Churchill, T A; Storey, K B

1992-03-01

451

Kirkwood-Buff derived force field for alkali chlorides in simple point charge water  

NASA Astrophysics Data System (ADS)

Solvated ions are a fundamental constituent of many biological systems. An important class consists of the alkali cations. In particular, potassium (K+) is the most abundant ion in the cytoplasm, whereas lithium (Li+), rubidium (Rb+), and cesium (Cs+) are of fundamental physicochemical and medical relevance. A powerful tool to understand ion specificity and cellular systems on a microscopic level is provided by molecular dynamics simulations. Previously, reliable force field parameters for Li+, K+, Rb+, and Cs+ in aqueous solution have not been available for the simple point charge (SPC) water model widely used in conjunction with the GROMOS force field. We used the Kirkwood-Buff theory to develop force fields for Li+, K+, Rb+, and Cs+ in SPC water to reproduce experimental data on respective aqueous alkali chloride solutions (LiCl, KCl, RbCl, CsCl). The force field developed reproduces many of the known properties of alkali metal chlorides solutions including densities and partial molar volumes. Our force field is shown to be superior to other common alkali chloride force fields in terms of reproducing the activity derivative, as a prerequisite for a realistic measure of ion-solute association underlying ion-specific phenomena (Hofmeister effects). For lithium and potassium, the ionic radii from cation-water oxygen pair correlation functions and hydration numbers are well reproduced. The force field developed will be useful for modeling physiological conditions and ion-specific phenomena for biomolecular systems.

Klasczyk, Benjamin; Knecht, Volker

2010-01-01

452

Performance evaluation of point-of-use water heaters. Final report 1 sep 79-15 oct 80  

SciTech Connect

Point-of-use water heaters are designed to be installed at the location where hot or warm water is used. Thus, such water heaters may be connected to a water faucet, dishwasher, clothes washer, shower or the like. Two types of heaters are available. One is referred to as instantaneous and it has no storage capacity. The second is a very small 1/2 to 6 gallon storage tank type of heater which has nearly negligible standby losses. Point-of-use water heaters offer the greatest potential for energy conservation on Army facilities when used as boosters for domestic dishwashers and to replace large storage heaters in buildings where the only requirement for hot or cold tepid water is in lavatories. A method has been developed to calculate the energy conservation potential of water heaters. The results of this method may be used for life-cycle cost analysis.

Shepherd, P.B.

1980-10-15

453

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model  

NASA Astrophysics Data System (ADS)

P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, that constitute alpine rock walls, has been denied in prior studies. These explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimeter-large low-porosity (<6 %) metamorphic, magmatic and sedimentary permafrost rock samples with a natural texture (>100 micro-fissures) from 25 °C to -15 °C in 0.3 °C increments close to the freezing point. P-wave velocity increases by 7-78 % when freezing parallel to cleavage/bedding and matrix velocity increases from 5-59 % coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's 2-phase equation implementing changes in matrix velocity dependent on lithology and demonstrate the physical basis for refraction seismics in low-porosity bedrock.

Draebing, D.; Krautblatter, M.

2012-02-01

454

Effect of freezing and dehydration on ion and cryoprotectant distribution and hemolymph volume in the goldenrod gall fly, Eurosta solidaginis  

Microsoft Academic Search

Extracellular freezing and dehydration concentrate hemolymph solutes, which can lead to cellular injury due to excessive water loss. Freeze tolerant larvae of the goldenrod gall fly, Eurosta solidaginis, may experience extreme cold and desiccation in winter. To determine whether larvae employ protective mechanisms against excessive cellular water loss we examined the effect of extracellular freezing and dehydration on hemolymph volume,

Jason B. Williams; Richard E. Lee

2011-01-01

455

The disinfection efficacy of a point-of-use water treatment system against bacterial, viral and protozoan waterborne pathogens  

Microsoft Academic Search

A point-of-use (POU) water treatment system (WTS), comprised of a presed activated carbon block filter followed by an ultraviolet (UV) light reactor, was evaluated for microbial disinfection efficacy following the general guidelines of the United States Environmental Protection Agency Guide Standard and Protocol for Testing Microbiological Water Purifiers. The POU WTS was challenged against bacterial, viral and protozoan waterborne pathogens

Morteza Abbaszadegan; Michaela N. Hasan; Charles P. Gerba; Peter F. Roessler; Barth R. Wilson; Roy Kuennen; Eric Van Dellen

1997-01-01

456

Difficulties in bringing point-of-use water treatment to scale in rural Guatemala.  

PubMed

In an earlier study in rural Guatemala, 257 households that received flocculant-disinfectant to treat their drinking water had 39% less diarrhea than 257