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1

Initial freezing point of Mozzarella cheese  

Microsoft Academic Search

The initial freezing point in unsalted fresh Mozzarella cheese was measured. The influence of the water-soluble solids on the freezing point depression of unsalted Mozzarella cheese was analyzed. Central temperature profiles and the initial freezing point of unsalted cylindrical cheese samples (1cm radius; 3cm height) were determined. A lyophilized aqueous extract of the soluble solids at pH 4.6 was obtained

Gustavo G. Ribero; Amelia C. Rubiolo; Susana E. Zorrilla

2007-01-01

2

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

3

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 freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the

J. I. Katz

2006-01-01

4

7.NS Comparing Freezing Points  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Ocean water freezes at about $-2 \\frac12 ^\\circ C$. Fresh water freezes at $0 ^\\circ C$. Antifreeze, a liquid used in the radiators of cars, freezes at...

5

When hot water freezes before cold  

NASA Astrophysics Data System (ADS)

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 heated, reducing the temperature of the freezing front, and thereby reducing the temperature gradient and heat flux, slowing the progress of the freezing front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

Katz, J. I.

2009-01-01

6

Phase separation of quaternary solubilized solutions or micro emulsion of hydrocarbons containing sodium oleate + phenol + benzene + water by freezing point measurements  

Microsoft Academic Search

Summary The depressions in freezing point measurements in quaternary solubilized solutions or micro-emulsion in sodium oleate + phenol + benzene + water are measured. Maxima and minima were observed, Gibbs' phase rule was applicable, eutectic points were detected, congruent melting points were obtained, loose combination of molecules or clusters, were formed, phases of the system transferred and finally unstable emulsion

Bhagwan Swaroop

1978-01-01

7

When hot water freezes before cold  

E-print Network

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

J. I. Katz

2006-04-27

8

When hot water freezes before cold  

E-print Network

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

Katz, J I

2006-01-01

9

A NOTE ON THE FREEZING-POINTS OF THE URINES OF TWO FRESH-WATER FISHES: THE CATFISH (AMEIURUS NEBULOSUS@ AND THE SUCKER (CATOSTOMUS COMMERSONI1)  

Microsoft Academic Search

In his book, Osmotic Regulation in Aquatic Animals, Krogh (1939) comments on the scarcity of available data for the osmotic concentra tion of the urines of fresh-water fishes. Since such data are appar ently not available for two of our common local forms, the catfish (Ameiurus nebulosus) and the sucker (Catostomus commersonii), we have been interested to make freezing-point determinations

CHARLOTTE HAYWOOD; MARY JEANNE CLAPP

10

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

11

Device and method for determining freezing points  

NASA Technical Reports Server (NTRS)

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

Mathiprakasam, Balakrishnan (Inventor)

1986-01-01

12

Thermosiphon solar water heater having freeze rupture protection  

Microsoft Academic Search

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

1986-01-01

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

New Type of Freezing-Point Apparatus. Freezing Points of Dilute Lanthanum Chloride Solutions  

Microsoft Academic Search

A new type of freezing-point apparatus is described that reduces the errors of previous types. The freezing-point depressions of aqueous lanthanum chloride solutions up to 0.04 m are adequately expressed by the Debye-Hu¨ckel approximation for ions with a=6.15 A plus a very small linear term. The ``higher terms'' are computed by combining the equations of Mayer and Kirkwood, using the

G. Scatchard; B. Vonnegut; D. W. Beaumont

1960-01-01

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

Freeze\\/thaw power system. [water expansion  

Microsoft Academic Search

A freeze-thaw power cycle is described that includes a piston driven by the expansion power of a fluid such as water in a cyclinder on freezing and the thawing thereof with alternate, rapid freezing and thawing of the fluid by low and high temperature means with heat transfer rates facilitated by the use of heat pipes or tubes or other

1978-01-01

17

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

18

Freezing of aqueous solution in a simple apparatus designed for measuring freezing point  

Microsoft Academic Search

Freezing point depression (FPD) measurement can be used as a fast means of determining solute concentration of an aqueous solution in the laboratory and the data are useful in the process design of low temperature operations, e.g. freeze concentration and freeze drying, etc. It is desirable to have a cost-effective device for FPD measurement. Here, we describe a simple device

Xiao Dong Chen; Ping Chen

1996-01-01

19

Study of freezing-point depression of selected food extracts  

SciTech Connect

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

Tanaka, Fumihiko [Kagoshima Univ. (Japan). Dept. of Agricultural Systems Engineering; Murata, Satoshi; Habara, Kazuhiro; Amaratunga, K.S.P. [Kyushu Univ., Fukuoka (Japan). Dept. of Agricultural Engineering

1996-12-31

20

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

21

Freezing Ice  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about freezing point. The probe is designed to find out whether students recognize that water freezes at the same time independent of the volume of water.

Francis Eberle

2007-01-01

22

Prediction of the freezing point of multicomponent liquid refrigerant solutions  

Microsoft Academic Search

The freezing point is one of the most critical properties required to complete the mathematical formulation related to the transport phenomena involved in the immersion chilling and freezing (ICF) of foods. Unfortunately, data for ternary and higher order systems are scarce. The aim of this work was to verify the validity of an excess Gibbs energy model for predicting the

Héctor A. Tello Alonso; Juan M. Peralta; Amelia C. Rubiolo; Susana E. Zorrilla

2011-01-01

23

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

24

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

25

A search for the Mpemba effect: When hot water freezes faster then cold water  

E-print Network

An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water, then the hot water will usually freeze first, if all other conditions are equal and remain so during cooling. The probability that the hot water will freeze first if it has the higher spontaneous freezing temperature will be larger for a larger difference in spontaneous freezing temperature. Heating the water may lower, raise or not change the spontaneous freezing temperature. The keys to observing hot water freezing before cold water are supercooling the water and having a significant difference in the spontaneous freezing temperature of the two water specimens. We observed hot water freezing before cold water 28 times in 28 attempts und...

Brownridge, James D

2010-01-01

26

STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING  

E-print Network

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

27

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

Microsoft Academic Search

In this paper, we report, for the first time, the effect of the lowered freezing point in a 50% water \\/ 50% antifreeze coolant (PAC) or 50% water \\/ 50% ethylene glycol (EG) solution by the addition of carbon nanotubes and other particles. The experimental results indicated that the nano materials are much more efficient (hundreds fold) in lowering the

Haiping Hong; Walter Roy

2007-01-01

28

High-freezing-point fuels used for aviation turbine engines  

NASA Technical Reports Server (NTRS)

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

Friedman, R.

1979-01-01

29

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

30

High freezing point fuels used for aviation turbine engines  

NASA Technical Reports Server (NTRS)

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

Friedman, R.

1979-01-01

31

A search for the Mpemba effect: When hot water freezes faster then cold water  

Microsoft Academic Search

An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water,

James D. Brownridge

2010-01-01

32

Influence of Vacuum Pasteurization upon the Freezing Point Value, Total Solids, and Concentration of Fluid Milk  

Microsoft Academic Search

SUMMARY The concentration of milk due to pasteurization in a Vacu-Therm pasteurizer was estimated by freezing point measurements, total solids determinations, and by condensing and trapping the water removed from the milk. Composite samples of raw and pasteurized milk were obtained during 3-hr. processing periods from the balance and surge tanks of the equipment. The temperature of pasteurization and the

J. T. Lazar Jr.; R. W. Henningson

1960-01-01

33

A study of the freezing of water in human uterine muscle by proton magnetic resonance.  

PubMed

Human uterine muscle and its nuclear fractions have been studied by means of nuclear magnetic resonance at temperatures from 300 degrees K to 143 degrees K. Different proton populations have been detected above and below the freezing point. On this basis it is suggested that the freezing of water in uterine muscle starts at the cell nuclei. PMID:4033376

Adamski, J; Olszewski, K J; Bu?ko, J; Pi?lewski, N

1985-01-01

34

Hot water can freeze faster than cold?!?  

E-print Network

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 story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon, while simple to describe, is deceptively complex, and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. We survey proposed theoretical mechanisms for the Mpemba effect, and the results of modern experiments on the phenomenon. Studies of the observation that hot water pipes are more ...

Jeng, M

2005-01-01

35

Immersion freezing of birch pollen washing water  

NASA Astrophysics Data System (ADS)

Up to now, the importance of pollen for atmospheric ice nucleation was considered to be minor, as they are too large to stay in the atmosphere for a long time. But as recent investigations have shown, not the pollen grains themselves are responsible for freezing, but easily suspendable macromolecules on their surfaces (Pummer et al., 2012). Due to the bursting of pollen grains these ice nucleating active (INA) macromolecules could be numerous in the atmosphere. 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, Hartmann et al., 2011). For this, washing water of two different birch pollen samples with different origin (Northern birch and Southern birch) were used. Immersion freezing of droplets generated from the pollen washing water was observed at temperatures higher than -20 °C for both samples. The main difference between the Northern and the Southern birch pollen was the temperature dependence of the immersion freezing process. Our results suggest that the ice nucleating potential of the Southern birch is controlled by a single type of INA macromolecule, while the Northern birch pollen seem to feature two distinctively different types of INA macromolecules. We determined the heterogeneous nucleation rates for both INA macromolecule types and thereby consistently describe the ice nucleation behavior of both, the Southern and the Northern birch pollen washing water. Furthermore we will suggest a theoretical framework for describing e.g. single INA macromolecule related ice nucleation in atmospheric models. References: Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S. and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen. Atmos. Chem. Phys., 12, 2541-2550, doi:10.5194/acp-12-2541-2012, 2012. Hartmann, S., Niedermeier, D., Voigtländer, J., Clauss, T., Shaw, R. A., Wex, H., Kiselev, A., and Stratmann, F.: Homogeneous and heterogeneous ice nucleation at LACIS: operating principle and theoretical studies, Atmos. Chem. Phys., 11, 1753-1767, doi:10.5194/acp-11-1753-2011, 2011.

Augustin, Stefanie; Hartmann, Susan; Pummer, Bernhard; Grothe, Hinrich; Niedermeier, Dennis; Clauss, Tina; Voigtländer, Jens; Tomsche, Laura; Wex, Heike; Stratmann, Frank

2013-04-01

36

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

37

Hot water can freeze faster than cold?!?  

E-print Network

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 story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon, while simple to describe, is deceptively complex, and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. We survey proposed theoretical mechanisms for the Mpemba effect, and the results of modern experiments on the phenomenon. Studies of the observation that hot water pipes are more likely to burst than cold water pipes are also described.

Monwhea Jeng

2005-12-29

38

Open Zinc Freezing-Point Cell Assembly and Evaluation  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

39

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...

40

Preventing livestock water from freezing. Forest Service project record  

Microsoft Academic Search

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

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

1983-01-01

41

Photomicrographic Investigation of Spontaneous Freezing Temperatures of Supercooled Water Droplets  

NASA Technical Reports Server (NTRS)

A photomicrographic technique for investigating eupercooled. water droplets has been devised and. used. to determine the spontaneous freezing temperatures of eupercooled. water droplets of the size ordinarily found. in the atmosphere. The freezing temperatures of 4527 droplets ranging from 8.75 to 1000 microns in diameter supported on a platinum surface and 571 droplets supported on copper were obtained. The average spontaneous freezing temperature decreased with decrease in the size of the droplets. The effect of size on the spontaneous freezing temperature was particularly marked below 60 microns. Frequency-distribution curves of the spontaneous freezing temperatures observed for droplets of a given size were obtained. Although no droplet froze at a temperature above 20 0 F, all droplets melted at 32 F. Results obtained with a copper support did not differ essentially from those obtained with a platinum surface.

Dorsch, R. G.; Hacker, P. T.

1950-01-01

42

Freeze concentration for removal of pharmaceutically active compounds in water  

Microsoft Academic Search

A progressive freeze concentration process, unidirectional downward freezing (UDF), was investigated for removal of five commonly used pharmaceuticals (ibuprofen, gemfibrozil, acetylsalicylic acid, metoprolol and sulfamethoxazole) in water. The feed water with the pharmaceutically active compounds (PhACs) at concentrations from ng\\/L to mg\\/L range was frozen at ?7 and ?15°C. The separation efficiency of PhACs in the single stage and two-stage

W. Gao; Y. Shao

2009-01-01

43

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

USGS Publications Warehouse

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

Moffitt, Christine M.; James, Christopher A.

2012-01-01

44

Universality of Tip Singularity Formation in Freezing Water Drops  

NASA Astrophysics Data System (ADS)

A drop of water deposited on a cold plate freezes into an ice drop with a pointy tip. While this phenomenon clearly finds its origin in the expansion of water upon freezing, a quantitative description of the tip singularity has remained elusive. Here we demonstrate how the geometry of the freezing front, determined by heat transfer considerations, is crucial for the tip formation. We perform systematic measurements of the angles of the conical tip, and reveal the dynamics of the solidification front in a Hele-Shaw geometry. It is found that the cone angle is independent of substrate temperature and wetting angle, suggesting a universal, self-similar mechanism that does not depend on the rate of solidification. We propose a model for the freezing front and derive resulting tip angles analytically, in good agreement with the experiments.

Marín, A. G.; Enríquez, O. R.; Brunet, P.; Colinet, P.; Snoeijer, J. H.

2014-08-01

45

Universality of tip singularity formation in freezing water drops.  

PubMed

A drop of water deposited on a cold plate freezes into an ice drop with a pointy tip. While this phenomenon clearly finds its origin in the expansion of water upon freezing, a quantitative description of the tip singularity has remained elusive. Here we demonstrate how the geometry of the freezing front, determined by heat transfer considerations, is crucial for the tip formation. We perform systematic measurements of the angles of the conical tip, and reveal the dynamics of the solidification front in a Hele-Shaw geometry. It is found that the cone angle is independent of substrate temperature and wetting angle, suggesting a universal, self-similar mechanism that does not depend on the rate of solidification. We propose a model for the freezing front and derive resulting tip angles analytically, in good agreement with the experiments. PMID:25126922

Marín, A G; Enríquez, O R; Brunet, P; Colinet, P; Snoeijer, J H

2014-08-01

46

Research on the Effect of Electric Charge on Initiation of Freezing of Supercooled Water  

NASA Astrophysics Data System (ADS)

The effect of applying the electric charge on the freezing of supercooled water was investigated using a pair of spherical electrodes, facing to each other in the test water. The reason for using a spherical end surface was to minimize unexpected high electrical density on the surface due to the existence of a singular point. After getting a uniform temperature, D. C. voltage was applied to the test section. Temperature, distance between two electrode sand the voltage applied were varied. It was found that supercooled water freeze in a few seconds after applying the electric charge. It was also found that the freezing is a statistical phenomenon. There are some tendencies, however, that the higher the value of D. C. voltage applied or the closer the distance between two electrodes are, the easier the water freeze. The electrical current was measured for every 0.05 seconds and it was found that the value increased while the voltage was being applied. The idea of a probability of freezing while a specific current flows for a time interval of ?t was introduced. The probability of freezing was calculated under two different conditions and the results were compared to each other to confirm the assumption. As a result, it was concluded that the probability depends only on the past record of current flow.

Okawa, Seiji; Saito, Akio; Fukao, Takeshi

47

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 quality,…

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

2007-01-01

48

A search for the Mpemba effect: When hot water freezes faster then cold water  

Microsoft Academic Search

An explanation for why hot water will sometime freeze more rapidly than cold\\u000awater is offered. Two specimens of water from the same source will often have\\u000adifferent spontaneous freezing temperatures; that is, the temperature at which\\u000afreezing begins. When both specimens supercool and the spontaneous freezing\\u000atemperature of the hot water is higher than that of the cold water,

James D. Brownridge

2010-01-01

49

STUDIES ON THE PHYSICAL STATE OF WATER IN LIVING CELLS AND MODEL SYSTEMS. IV. FREEZING AND THAWING POINT DEPRESSION OF WATER BY GELATIN, OXYGEN-CONTAINING POLYMERS AND UREA-DENATURED PROTEINS  

Microsoft Academic Search

Using a differential scanning calorimeter, we studied the freezing and thawing behavior of solutions of six globular proteins (hemoglobin, bovine serum albumin, y-globulin, P- lactoglobulin, egg albumin, and protamine sulfate); gelatin; and three synthetic polymers (polyvinylpyrrolidone (PVP), polyvinylmethylether (PVME), andpoly(ethy1ene oxide) (PEO)). The native globular proteins in concentrations up to 50% produced no major change of the freezing temperature of

G. N. LING; Z. L. ZHANG

50

A search for the Mpemba effect: When hot water freezes faster then cold water James D. Brownridge  

E-print Network

A search for the Mpemba effect: When hot water freezes faster then cold water James D. Brownridge, and you determine that the hot water freezes first. Did you observe the Mpemba effect?1 The Mpemba effect investigators. Before starting the search for the Mpemba effect, the meaning of freezing faster or freezing

Suzuki, Masatsugu

51

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

NASA Technical Reports Server (NTRS)

The objectives were the design, performance and economic analyses of practical aircraft fuel heating systems that would permit the use of high freezing-point fuels on long-range aircraft. Two hypothetical hydrocarbon fuels with freezing points of -29 C and -18 C were used to represent the variation from current day jet fuels. A Boeing 747-200 with JT9D-7/7A engines was used as the baseline aircraft. A 9300 Km mission was used as the mission length from which the heat requirements to maintain the fuel above its freezing point was based.

Pasion, A. J.

1979-01-01

52

Fuel freeze-point investigations. Final report, September 1982-March 1984  

SciTech Connect

The objective of this program was to conduct a detailed assessment of the low-temperature environment to which USAF aircraft are exposed for the purpose of defining a maximum acceptable fuel freeze-point and also to define any operational changes required with the use of a high freeze-point fuel. A previous study of B-52, C-141, and KC-135 operational missions indicated that the -58 C freeze point specification was too conservative. Based on recommendations resulting from the previous program, several improvements in the method of analysis were made, such as: expansion of the atmospheric temperature data base, the addition of ground temperature analysis, the addition of fuel-freezing analysis to the one-dimensional fuel-temperature computer program, and the examination of heat transfer in external fuel tanks, such as pylon or tip tanks. The B-52, C-141, and KC-135 mission were analyzed again, along with the operational missions of two tactical airplanes, the A-10 and F-15; -50C was determined to be the maximum allowable freeze point for a general-purpose USAF aviation turbine fuel. Higher freeze points can be tolerated if the probability of operational interference is acceptably low or if operational changes can be made. Study of atmospheric temperatures encountered for the missions of the five-study aircraft indicates that a maximum freeze point of -48 C would not likely create any operational difficulties in Northern Europe.

Desmarais, L.A.; Tolle, F.F.

1984-07-01

53

FREEZING WATER CLEANING A POSSIBLE IMPROVEMENT IN SRF CAVITY RINSING*  

E-print Network

method of high pressure rinsing - freezing water cleaning - consists in preliminary cooling down to further increase accelerating gradients do not cease. Dry ice cleaning [2, 3] is a prominent example the traditional HPR are at hand in any SRF lab, a simple cooling down of the cavity before rinsing can

54

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

2013-07-11

55

Fuel freeze-point investigations. Final report, September 1982March 1984  

Microsoft Academic Search

The objective of this program was to conduct a detailed assessment of the low-temperature environment to which USAF aircraft are exposed for the purpose of defining a maximum acceptable fuel freeze-point and also to define any operational changes required with the use of a high freeze-point fuel. A previous study of B-52, C-141, and KC-135 operational missions indicated that the

L. A. Desmarais; F. F. Tolle

1984-01-01

56

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

57

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

58

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.

59

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

60

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

PubMed

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

Kiyosawa, Keitaro

2003-05-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

62

When does hot water freeze faster then cold water? A search for the Mpemba effect  

NASA Astrophysics Data System (ADS)

It is possible to consistently observe hot water freezing faster than cold water under certain conditions. All conditions except the initial temperature of water specimens must be the same and remain so during cooling, and the cold water must supercool to a temperature significantly lower than the temperature to which the hot water supercools. For hot water at an initial temperature of >?80 °C and cold water at water must supercool to a temperature of at least ?5.5 °C, lower than the temperature to which hot water supercools. With these conditions satisfied, we observed initially hot water freezing before the initially cold water 28 times in 28 attempts. If the cold water does not supercool, it will freeze before the hot water because it always cools to 0 °C first regardless of the initial temperatures.

Brownridge, James D.

2011-01-01

63

When does hot water freeze faster then cold water? A search for the Mpemba effect  

Microsoft Academic Search

It is possible to consistently observe hot water freezing faster than cold water under certain conditions. All conditions except the initial temperature of water specimens must be the same and remain so during cooling, and the cold water must supercool to a temperature significantly lower than the temperature to which the hot water supercools. For hot water at an initial

James D. Brownridge

2011-01-01

64

Self-Association of Nicotinamide in Aqueous Solution: Mass Transport, Freezing-Point Depression, and Partition Coefficient Studies  

Microsoft Academic Search

The steady-state flux (SSF) of nicotinamide from an aqueous donor phase across a model Silastic membrane did not increase proportionally with increasing donor phase concentration. The suspected self-association of the drug in aqueous solution was evaluated by studying the concentration-dependent changes in (i) the molal osmotic coefficient of nicotinamide (freezing-point depression studies) and (ii) the partition coefficient between water and

William N. Charman; Christine S. C. Lai; Barrie C. Finnin; Barry L. Reed

1991-01-01

65

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

66

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

67

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

NASA Technical Reports Server (NTRS)

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

Mathiprakasam, B.

1982-01-01

68

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

69

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

Microsoft Academic Search

For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit.

Keitaro Kiyosawa

2003-01-01

70

Critical viewpoints on the methods of realizing the metal freezing points of the ITS-90  

NASA Astrophysics Data System (ADS)

The time-honored method for realizing the freezing point tf of a metal (in practice necessarily a dilute alloy) is that of continuous, slow freezing where the plateau temperature (which is the result of solidifying material's being so pure that its phase-transition temperature is observably constant) is measured. The freezing point being an equilibrium temperature, Ancsin considers this method to be inappropriate in principle: equilibrium between the solid and liquid phases cannot be achieved while the solid is being cooled to dispose of the releasing latent heat and while it is accreting at the expense of the liquid. In place of the continuous freezing method he has employed the pulse-heating method (in which the sample is allowed to approach equilibrium after each heat pulse) in his study of Ag; his measurements suggest that freezing can produce non-negligible errors. Here we examine both methods and conclude that the freezing method, employing an inside solid-liquid interface thermally isolated by an outside interface, can provide realizations of the highest accuracy; in either method, perturbation, by inducing solid-liquid phase transition continuously or intermittently, is essential for detecting equilibrium thermally. The respective merits and disadvantages of these two methods and also of the inner-melt method are discussed. We conclude that in a freezing-point measurement what is being measured is in effect the however minutely varying phase transition, and nonconstitutional equilibrium, temperature ti at the solid-liquid interface. The objective is then to measure the ti that is the best measure of tf, which is, normally, the plateau temperature.

Ma, C. K.

1995-08-01

71

A water activity based model of heterogeneous ice nucleation kinetics for freezing of water and aqueous solution droplets.  

PubMed

Immersion freezing of water and aqueous solutions by particles acting as ice nuclei (IN) is a common process of heterogeneous ice nucleation which occurs in many environments, especially in the atmosphere where it results in the glaciation of clouds. Here we experimentally show, using a variety of IN types suspended in various aqueous solutions, that immersion freezing temperatures and kinetics can be described solely by temperature, T, and solution water activity, a(w), which is the ratio of the vapour pressure of the solution and the saturation water vapour pressure under the same conditions and, in equilibrium, equivalent to relative humidity (RH). This allows the freezing point and corresponding heterogeneous ice nucleation rate coefficient, J(het), to be uniquely expressed by T and a(w), a result we term the a(w) based immersion freezing model (ABIFM). This method is independent of the nature of the solute and accounts for several varying parameters, including cooling rate and IN surface area, while providing a holistic description of immersion freezing and allowing prediction of freezing temperatures, J(het), frozen fractions, ice particle production rates and numbers. Our findings are based on experimental freezing data collected for various IN surface areas, A, and cooling rates, r, of droplets variously containing marine biogenic material, two soil humic acids, four mineral dusts, and one organic monolayer acting as IN. For all investigated IN types we demonstrate that droplet freezing temperatures increase as A increases. Similarly, droplet freezing temperatures increase as the cooling rate decreases. The log10(J(het)) values for the various IN types derived exclusively by Tand a(w), provide a complete description of the heterogeneous ice nucleation kinetics. Thus, the ABIFM can be applied over the entire range of T, RH, total particulate surface area, and cloud activation timescales typical of atmospheric conditions. Lastly, we demonstrate that ABIFM can be used to derive frozen fractions of droplets and ice particle production for atmospheric models of cirrus and mixed phase cloud conditions. PMID:24601020

Knopf, Daniel A; Alpert, Peter A

2013-01-01

72

Freeze-protection loop for direct solar-water-heating systems. Final report  

SciTech Connect

Even a one-time freeze condition can do destructive damage to a direct solar water heating system. The project funded under grant DE-FG4480R4, 1-1-80 to 8-1-81, proposed to demonstrate a simple installation procedure whereby thermosiphoning warm water from storage would prevent solar collectors from freezing. Installing the freeze protection loop in owner maintained solar systems was inconclusive. Owners were not attentive to freeze warnings or did not understand the simple instructions. A controlled situation was established using a refrigerator to produce below freezing temperatures. Experiments conducted with this equipment showed that the thermosiphoning principle could not be relied on to prevent freezing. Thermosiphoning cannot be relied on to prevent freezing in a direct solar water heating system. The direct system is an effective means of heating water in north Florida, but the system must be drained, either manually or automatically, to provide reliable system protection.

Not Available

1981-11-04

73

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

74

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

75

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

76

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

77

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

2009-05-01

78

Metabolic Activity of Permafrost Bacteria below the Freezing Point  

PubMed Central

Metabolic activity was measured in the laboratory at temperatures between 5 and ?20°C on the basis of incorporation of 14C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5°C) to 20 days (?10°C) to ca. 160 days (?20°C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature. PMID:10919774

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

2000-01-01

79

Metabolic activity of permafrost bacteria below the freezing point  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

80

A Four-Zone Furnace for Realization of Silver and Gold Freezing Points  

NASA Astrophysics Data System (ADS)

Recently, the Thermocouple Calibration Laboratory at the National Institute of Standards and Technology has used sodium heat-pipe furnaces for the realization of ITS-90 freezing points of aluminum, silver, and gold. When using a fixed-point cell mounted in a long silica-glass tube that extends to ambient temperature at the top of the furnace, we have observed significant thermal gradients along the well of the fixed-point cell, with the top of the well up to 0.1 K colder than the bottom. Furthermore, the heat-pipe lifetime is limited when used at the gold point (1064.18 °C) for more than a few hundred hours. To address these problems, we have designed and built a four-zone furnace based on a temperature-controlled, graphite isothermal block, suspended inside a three-zone tube furnace. The three-zone furnace is of a commercial design. The graphite block is enclosed in an alloy 600 (Inconel) can, allowing the graphite to be maintained in an argon atmosphere. The argon pressure is maintained at one atmosphere at all temperatures, thereby greatly reducing the stress on the can. Heaters in intimate contact with the can allow temperature control of the fourth inner zone to high accuracy. In this paper, the measured thermal stability and uniformity achieved with this furnace are presented. We also give results of test freezes of a silver freezing-point cell.

Ripple, D. C.; Garrity, K. M.; Meyer, C. W.

2003-09-01

81

Relationship between freezing tolerance and shoot water relations of western red cedar.  

PubMed

Freezing tolerance and shoot water relations parameters of western red cedar (Thuja plicata Donn) seedlings were measured every 2 weeks from October 1989 to April 1990. Freezing tolerance, measured by freeze-induced electrolyte leakage, showed seasonal shifts in the temperature causing 50% foliage electrolyte leakage (LT(50)). The LT(50) value was -4 degrees C in October, it decreased to -20 degrees C in February and then increased to -6 degrees C in April. The foliage index of injury at -10 degrees C (II(-10)) also showed seasonal shifts from a high of 98% in October to a low of 18% in February followed by an increase to 82% in April. Osmotic potentials at saturation (Psi(s(sat))) and turgor loss point (Psi(s(tlp))) were, respectively, -1.07 and -1.26 MPa in October, -1.57 and -2.43 MPa in January, and -1.04 and -1.86 MPa in April. Dry weight fraction (DWF) increased and symplastic volume at full turgor (V(o)) decreased during the fall-winter acclimation phase, whereas DWF decreased and V(o) increased during the late winter-spring deacclimation phase. Relationships between seasonal patterns of freezing tolerance and shoot water relations parameters showed that LT(50) and II(-10) decreased linearly as Psi(s(tlp)) and V(o) decreased and DWF increased. There was no discernible difference in the relationship during fall acclimation or spring deacclimation. The freezing dehydration index at -10 degrees C (FDI(-10)) declined from 0.69 in November to 0.41 in February and increased to 0.56 in April. The value of II(-10) decreased linearly as FDI(-10) decreased, although a measurement made on actively growing spring foliage did not fit this relationship. The results indicate that seasonal changes in freezing tolerance of western red cedar are partially due to changes in tissue water content, symplastic volume, passive osmotic adjustment and FDI(-10). PMID:14969948

Grossnickle, S C

1992-10-01

82

Numerical analysis of the heat transfer associated with freezing\\/solidifying phase changes for a pipeline filled with crude oil in soil saturated with water during pipeline shutdown in winter  

Microsoft Academic Search

A flow and heat transfer model for a crude oil pipeline buried in soil saturated with water during shutdown, where ambient temperature is below the freezing point of water, has been established. Phase changes involving water freezing in the soil and crude oil solidifying in the pipeline and the influence of initial temperature and flow field were included in the

Tao Lu; Kui-sheng Wang

2008-01-01

83

The Evaluation of the Emissivity and the Temperature of Cavities at the Gold Freezing Point  

NASA Astrophysics Data System (ADS)

In the present investigation, the integral equation for the temperature distribution inside the cavity at the gold freezing point, and the relation between the emissivity and the local temperature have been derived according to the basic ideas of Geist. In addition, we have calculated the changes of the temperature and emissivity of the bottom of a baffled cylindrical cavity due to the changes in the temperature of the baffle. Some typical results are given here.

Hongpan, Chen; Shouren, Chen; Zaixiang, Chu

1981-04-01

84

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

85

Bovine serum albumin: survival and osmolarity effect in bovine spermatozoa stored above freezing point.  

PubMed

Liquid nitrogen preservation in remote farms is a limitation. The goal of this study was to determine optimum temperature above freezing point for bovine spermatozoa preservation using bovine serum albumin (BSA) as a supplementation. Pooled semen sample from three ejaculates was subjected to various BSA concentration (1, 4, 8 and 12 mg ml(-1)), before incubation in different above freezing point temperatures (4, 25 and 37 °C). Viability assessment was carried out against time from day 0 (fresh sample) until all spermatozoa become nonviable. Optimal condition for bovine spermatozoa storage was at 4 °C with 1 mg ml(-1) BSA for almost 7 days. BSA improved bovine spermatozoa viability declining rate to 44.28% at day 4 and 57.59% at day 7 compared to control, with 80.54% and 98.57% at day 4 and 7 respectively. Increase in BSA concentration did not improve sperm viability. Our results also confirmed that there was a strong negative correlation between media osmolarity and bovine spermatozoa survival rate with r = 0.885, P < 0.0001. Bovine serum albumin helps to improve survival rate of bovine spermatozoa stored above freezing point. PMID:21806660

Nang, C F; Osman, K; Budin, S B; Ismail, M I; Jaffar, F H F; Mohamad, S F S; Ibrahim, S F

2012-05-01

86

The migration and transformation of dissolved organic matter during the freezing processes of water.  

PubMed

This study investigated the partitioning behavior of dissolved organic matter (DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the increase in dissolved organic carbon (DOC) concentration of feed water, caused an increase in DOM captured in the ice phase. The ultraviolet-absorbing compounds, trihalomethane precursors, as well as fulvic acid- and humic acid-like fluorescent materials, were more liable to be to be rejected from the ice phase and were more easily retained in the unfrozen liquid phase during water freezing, as compared with organics (on average) that comprise DOC. In addition, it was also found a higher accumulation of these organics in the unfrozen liquid phase during water freezing at higher temperature. The freeze/thaw processes altered the quantity, optical properties, and chlorine reactivity of DOM. The decrease in ultraviolet light at 254nm as well as the production of aromatic protein- and soluble microbial byproduct-like fluorescent materials in DOM due to freeze/thaw were consistently observed. On the other hand, the changes in DOC, trihalomethane formation potential, and fulvic acid- and humic acid-like fluorescence caused by freeze/thaw varied significantly between samples. PMID:25597675

Xue, Shuang; Wen, Yang; Hui, Xiujuan; Zhang, Lina; Zhang, Zhaohong; Wang, Jie; Zhang, Ying

2015-01-01

87

The freezing process of continuously sprayed water droplets on the superhydrophobic silicone acrylate resin coating surface  

NASA Astrophysics Data System (ADS)

This study conducted experiments on freezing process of water droplets on glass slides covered with superhydrophobic coatings under the continuous water spray condition in the artificial climatic chamber which could simulate low temperature and high humidity environments. The freezing mechanism and freezing time of water droplets under the condition of continuous spray were observed by the microscope and were compared with those of the single static droplet. Then, differences of freezing process between continuously sprayed droplets and single static droplet were analyzed. Furthermore, the effects of static contact angle (CA), contact angle hysteresis (CAH) and roughness of the superhydrophobic coating surface on the freezing time of continuously sprayed droplets were explored. Results show that the freezing process of the continuously sprayed droplets on the superhydrophobic coating started with the homogeneous nucleation at gas-liquid interfaces. In addition, the temperature difference between the location near the solid-liquid interface and the location near the gas-liquid interface was the key factor that influenced the ice crystallization mechanism of water droplets. Moreover, with the larger CA, the smaller CAH and the greater roughness of the surface, droplets were more likely to roll down the surface and the freezing duration on the surface was delayed. Based on the findings, continuous water spray is suggested in the anti-icing superhydrophobic coatings research.

Hu, Jianlin; Xu, Ke; Wu, Yao; Lan, Binhuan; Jiang, Xingliang; Shu, Lichun

2014-10-01

88

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

PubMed

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

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

2015-01-01

89

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

90

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

91

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

SciTech Connect

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. [Isothermal Technology Ltd (Isotech), Pine Grove, Southport, Merseyside, PR9 9AG, England (United Kingdom)] [Isothermal Technology Ltd (Isotech), Pine Grove, Southport, Merseyside, PR9 9AG, England (United Kingdom)

2013-09-11

92

Freeze\\/thaw induced demulsification of water-in-oil emulsions with loosely packed droplets  

Microsoft Academic Search

Freeze\\/thaw treatment has been widely investigated for phase separation of oil-in-water (O\\/W) emulsions. However, it is a new application for destroying the inverted emulsions, water-in-oil (W\\/O) emulsions. In this study, freeze\\/thaw treatment was used to break the W\\/O emulsions with loosely packed droplets that were produced from the oils generally adopted as membrane phase in emulsion liquid membrane (ELM) process.

Chang Lin; Gaohong He; Xiangcun Li; Lin Peng; Chunxu Dong; Shuang Gu; Gongkui Xiao

2007-01-01

93

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

PubMed

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

Zavitsas, Andreas A

2010-05-25

94

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

NASA Astrophysics Data System (ADS)

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 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°C freeze immediately when this surface is heated to -8°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.

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

2010-02-01

95

Aqueous propylene-glycol concentrations for the freeze protection of thermosyphon solar energy water heaters  

Microsoft Academic Search

Using a validated dynamic simulation model, the thermal performance of an indirect thermosyphon solar energy water heater was examined. The heat transfer fluids employed were aqueous solutions of propylene glycol. The effect of varying the glycol concentration on the hot water output and efficacy of freeze protection was determined for a specific pattern of hot water withdrawal and weather for

B. Norton; J. E. J. Edmonds

1991-01-01

96

Nanosecond freezing of water under multiple shock wave compression: Continuum modeling and wave profile measurements  

Microsoft Academic Search

Using real time optical transmission and imaging measurements in multiple shock wave compression experiments, water was shown to solidify on nanosecond time scales [D. H. Dolan and Y. M. Gupta, J. Chem. Phys. 121, 9050 (2004)]. Continuum modeling and wave profile measurements, presented here, provide a complementary approach to examine the freezing of shocked water. The water model consisted of

D. H. Dolan; J. N. Johnson; Y. M. Gupta

2005-01-01

97

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

98

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

99

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

100

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

NASA Astrophysics Data System (ADS)

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 is the following: The hot water supercools, but only slightly, before spontaneously freezing. Superficially it looks completely frozen. The cold water (in larger volume than that of the hot sample) supercools to a lower local temperature than the hot before it spontaneously freezes. This scenario can occur more often for ambient cooling temperatures between -6 °C and -12 °C.

Auerbach, David

1995-10-01

101

The freezing point depression of mammalian tissues in relation to the question of osmotic activity of cell fluid.  

PubMed

The freezing point depression of freshly excised frozen tissues, pulverized in a hydraulic press or in a mortar, is greater than that of plasma. Even at 0 degrees C. the freezing point depression of such homogenates increases significantly with time. Dilution data indicate that such freezing point data are valid. The presence of intact cells has been shown in smears of tissues pulverized in a mortar, but not in smears of those crushed in a hydraulic press. The osmolarity of various diluent solutions affects the calculated osmotic activity of tissue homogenates presumably because of delayed diffusion between the diluent and cell fluid. With a hypertonic NaCl diluent, spuriously low values of tissue osmotic activity are found from calculations assuming instantaneous mixing between homogenates and diluents. The limitations of data from cryoscopic experiments and from tissue-swelling experiments are discussed in relation to the basic question of whether or not cell fluid is isotonic to extracellular fluid. PMID:13385447

APPELBOOM, J W; BRODSKY, W A; DENNIS, W H; DIAMOND, I; MILEY, J F; REHM, W S

1956-11-20

102

Freezing of ridges and water networks preserves the Gamburtsev Subglacial Mountains for millions of years  

NASA Astrophysics Data System (ADS)

Once an ice sheet grows beyond a critical thickness, the basal thermal regime favors melting and development of subglacial water networks. Subglacial water is necessary for bedrock erosion, but the exact mechanisms that lead to preservation of subglacial topography are unclear. Here we resolve the freezing mechanisms that lead to long-term, high-altitude preservation across the Gamburtsev Subglacial Mountains in East Antarctica. Analyses of a comprehensive geophysical data set reveal a large-scale water network along valley floors. The ice sheet often drives subglacial water up steep topography where it freezes along high ridges beneath thinner ice. Statistical tests of hypsometry show the Gamburtsevs resemble younger midlatitude mountains, indicating exceptional preservation. We conclude that the Gamburtsevs have been shielded from erosion since the latest Eocene (˜34 Ma). These freezing mechanisms likely account for the spatial and temporal patterns of erosion and preservation seen in other glaciated mountain ranges.

Creyts, Timothy T.; Ferraccioli, Fausto; Bell, Robin E.; Wolovick, Michael; Corr, Hugh; Rose, Kathryn C.; Frearson, Nicholas; Damaske, Detlef; Jordan, Tom; Braaten, David; Finn, Carol

2014-11-01

103

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

104

Investigation into the Mpemba Effect: Variation in the Freezing Time of Water Dependent on Initial Temperature and Purity  

Microsoft Academic Search

The observation that hot water sometimes appears to freeze more quickly than cold water, known as the Mpemba effect, has generated vigorous debate. Prior research [1] into the Mpemba effect has resulted in conflicting results, due to a variety of observation techniques, multiple definitions of freezing, and different water treatments. To clarify the previous results, we have tested multiple types

Ingrid Thvedt; Martha Roseberry; Susan Lehman

2009-01-01

105

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

106

Homogeneous Freezing of Water Droplets and its Dependence on Droplet Size  

NASA Astrophysics Data System (ADS)

The formulation and parameterisation of microphysical processes in tropospheric clouds, such as phase transitions, is still a challenge for weather and climate models. This includes the homogeneous freezing of supercooled water droplets, since this is an important process in deep convective systems, where almost pure water droplets may stay liquid until homogeneous freezing occurs at temperatures around 238 K. Though the homogeneous ice nucleation in supercooled water is considered to be well understood, recent laboratory experiments with typical cloud droplet sizes showed one to two orders of magnitude smaller nucleation rate coefficients than previous literature results, including earlier results from experiments with single levitated water droplets and from cloud simulation experiments at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) facility. This motivated us to re-analyse homogeneous droplet freezing experiments conducted during the previous years at the AIDA cloud chamber. This cloud chamber has a volume of 84m3 and operates under atmospherically relevant conditions within wide ranges of temperature, pressure and humidity, whereby investigations of both tropospheric mixed-phase clouds and cirrus clouds can be realised. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. According to our new results and their comparison to the results from single levitated droplet experiments, the homogeneous freezing of water droplets seems to be a volume-dependent process, at least for droplets as small as a few micrometers in diameter. A contribution of surface induced freezing can be ruled out, in agreement to previous conclusions from the single droplet experiments. The obtained volume nucleation rate coefficients are in good agreement, within error bars, with some previous literature data, including our own results from earlier AIDA experiments, but they do not agree with recently published lower volume nucleation rate coefficients. This contribution will show the results from the re-analysis of AIDA homogeneous freezing experiments with pure water droplets and will discuss the comparison to the literature data.

Schmitt, Thea; Möhler, Ottmar; Höhler, Kristina; Leisner, Thomas

2014-05-01

107

A New Predictive Equation for the Depression in Freezing Points of Multicomponent Aqueous Solutions Conforming to the Linear Isopiestic Relation  

Microsoft Academic Search

The linear isopiestic relation has been used together with a well-known thermodynamic equation to establish a new predictive equation for freezing point depression. This equation can provide predictions for multicomponent solutions conforming to the linear isopiestic relation using only information on the corresponding binary subsystems. The predictive capability of the equation has been tested by comparing with the experimental data

Yu-Feng Hu; Shuan-Shi Fan

2001-01-01

108

A Study of Ionic Association in Aqueous Solutions of Bi-Bivalent Electrolytes by Freezing-Point Measurements  

Microsoft Academic Search

Measurements of freezing-point depression with a precision of ± 0\\\\cdot 0002 degrees C have been made on aqueous solutions of potassium chloride and the sulphates of copper, zinc, magnesium, calcium, cobalt and nickel. The results for the sulphates have been analyzed using the theory of incomplete dissociation in a manner which makes clear the physical status of the dissociation constants

P. G. M. Brown; J. E. Prue

1955-01-01

109

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

110

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

111

The effects of hydrophobic surface treatments on dropwise condensation and freezing of water. Final report  

Microsoft Academic Search

The effects of hydrophobic coatings on the dropwise condensation and freezing process for water on a flat horizontal copper plate held at a temperature much lower than the surrounding air was investigated. Extensive qualitative and quantitative data were taken to describe these effects in terms of dropsize distributions, heat and mass transfer coefficients, and digital imaging of the microscopic condensing

J. A. Bryant

1996-01-01

112

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.)

113

Freezing lake  

NSDL National Science Digital Library

Finite difference solution to mixed conduction-convection limited freezing of a 10 cm thick pool of water, with benchmark against analytical timescales. Requisite software: Gnumeric or Excel to open spreadsheets in source directory.

Powell, Adam C., IV

2005-02-23

114

Calculations of Freezing Point Depression, Boiling Point Elevation, Vapor Pressure and Enthalpies of Vaporization of Electrolyte Solutions by a Modified Three-Characteristic Parameter Correlation Model  

Microsoft Academic Search

A method was proposed for calculating the thermodynamic properties, freezing point depression, boiling point elevation, vapor\\u000a pressure and enthalpy of vaporization for single solute electrolyte solutions, including aqueous and nonaqueous solutions,\\u000a based on a modified three-characteristic-parameter correlation model. When compared with the corresponding literature values,\\u000a the calculated results show that this method gives a very good approximation, especially for 1-1

Xinlei Ge; Xidong Wang

2009-01-01

115

Freezing of water adsorbed on hydrophobic and activated soot particles  

NASA Astrophysics Data System (ADS)

Dynamics and structure of water adsorbed on aviation-kerosene flame soot are studied by neutron scattering. Gravimetry and chromatography are used to determine the amount and the distribution of adsorbed water, and the organics surface coverage. At high relative humidity kerosene flame soot adsorbs less than one statistical water layer. Removing the polyaromatic hydrocarbon coverage by a heating treatment leads to highlight polar active sites and make the soot more hydrophilic, like sulfate activated soot that adsorbs up to five water layers at high relative humidity. Without activation, kerosene flame soot particles act as poorly effective ice nuclei in the atmosphere.

Demirdjian, Benjamin; Ferry, Daniel; Suzanne, Jean; Popovicheva, Olga B.; Persiantseva, Natalia M.; Kamaev, Andrey V.; Shonija, Natalia K.; Zubareva, Nina A.

2009-10-01

116

Freezing Models For Heterogeneous Drop Freezing In Immersion and Contact Modes  

Microsoft Academic Search

Field measurements showed that supercooled liquid water drops and frozen drops can coexist in tropospheric clouds at temperatures down to -40 C with an incidence of ice particles already at -4 C. The freezing behaviour of water drops depends on their sizes, on their content of soluble particles (freezing point depression) and of insoluble particles (potential immersion ice nuclei) as

K. Diehl; S. Wurzler

2002-01-01

117

Water freezing as a regiocontrol element in the multicomponent assembly of cyclic enones.  

PubMed

Regioselective synthesis of dialkoxy 2-cyclopentenones and 2-cyclohexenones with novel substitution patterns has been accomplished by the one-pot combination of three simple starting materials (chromium carbene complex, Weinreb acetamide lithium enolate and 1-alkoxyallenyllithium) under either anhydrous conditions or water-promoted solidification of the reaction mixture. These results revealed an unprecedented water-freezing effect that plays a key role to completely reverse the regioselectivity of the intramolecular carbometalation of an allene moiety. PMID:25418199

De la Campa, Raquel; Flórez, Josefa

2015-01-26

118

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

119

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

120

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

SciTech Connect

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

Hayashi, K.; Kasza, K.

2000-05-03

121

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

122

Final report for the APMP.T-K4: Comparison of realizations of aluminium freezing-point temperatures  

NASA Astrophysics Data System (ADS)

The comparison APMP.T-K4 is the regional extension of the CCT-K4: an intercomparison of the realizations of the freezing-points of Al (660.323 °C) and Ag (961.78 °C). The comparison was organized in two loops and four sub-loops with high temperature standard platinum resistance thermometers (HTSPRTs) as transfer thermometers in the freezing-point comparisons. The comparison involved eight APMP NMIs (KRISS, NMIJ, SCL, NMC, CMS, NIMT, SIRIM, NPL), and KRISS and NMIJ acted as linking laboratories to the CCT-K4. The transfer HTSPRTs showed a strong drift during the transportation between the NMIs. In the case of the Ag freezing-point comparison, the comparison results were scattered much more than expected. In the APMP meeting held in 2009, the participants agreed that the Ag comparison results would be omitted in the report. It revealed that the measurement results at the Al freezing-point of participants were in agreement with the key comparison reference value of the CCT-K4 within 4 mK except for one laboratory. Details of the comparison results, the uncertainty evaluation and the drift of the HTSPRTs are described in this report. 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 (CIPM MRA).

Gam, K. S.; Joung, W.; Yamazawa, K.; Cheung, C. P.; Y Kho, H.; Wang, L.; Tsai, S. F.; Norranim, U.; Hafidzah, O.; Gupta, J. K.

2013-01-01

123

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

Microsoft Academic Search

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

Bodnar

1993-01-01

124

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

125

Investigation into the Mpemba Effect: Variation in the Freezing Time of Water Dependent on Initial Temperature and Purity  

NASA Astrophysics Data System (ADS)

The observation that hot water sometimes appears to freeze more quickly than cold water, known as the Mpemba effect, has generated vigorous debate. Prior research [1] into the Mpemba effect has resulted in conflicting results, due to a variety of observation techniques, multiple definitions of freezing, and different water treatments. To clarify the previous results, we have tested multiple types of water and improved the sample monitoring. During cooling and freezing, each 50 g water sample is continually monitored by three thermistors at different depths. Samples of tap, distilled, and nanopure water were heated, heated and cooled, or boiled before being frozen. We monitor the time to reach freezing, the duration of freezing, and the total time to reach -7^oC. We observe the Mpemba effect most consistently in the length of the freezing transition in tap water. Observations of temperature variation during freezing will also be presented. [1] See the review by M. Jeng, Am.J.Phys. 74 514 (2006).

Thvedt, Ingrid; Roseberry, Martha; Lehman, Susan

2009-03-01

126

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

127

Water transport in epididymal and ejaculated rhesus monkey ( Macaca mulatta) sperm during freezing  

Microsoft Academic Search

In the present study, we report the effects of cooling ejaculated and epididymal rhesus monkey (Macacamulatta) sperm with and without the presence of a cryoprotective agent, glycerol. Water transport data during freezing of ejaculated and epididymal sperm cell suspensions were obtained at a cooling rate of 20°C\\/min in the absence of any cryoprotective agents and in the presence of 0.7M

Raghava Alapati; Kelly Goff; Hans Michael Kubisch; Ram V. Devireddy

2008-01-01

128

Fabrication of two-dimensional nanosheets via water freezing expansion exfoliation  

NASA Astrophysics Data System (ADS)

Layered materials, if exfoliated effectively, will exhibit several unique properties, offering great potential for diverse applications. To this end, in this study, we develop a novel, universal, and environmentally friendly method named as ‘water freezing expansion exfoliation’ for producing two-dimensional nanosheets. This method exploits the expansion in the volume of water upon freezing. When the water freezing expansion condition is reproduced in layered materials, the layers exfoliate to overcome the van der Waals force between them. The expansion process is performed by repeated cycling between 4 °C and ?20 °C to effectively exfoliate layered materials of graphite, hexagonal boron nitride (h-BN), MoS2 and WS2. Systematic characterization of the samples thus obtained using electron microscopy and optical studies substantiate the formation of thin flakes (graphene, h-BN, MoS2, and WS2 nanosheets). The method demonstrated in this study is cost-effective and does not demand sophisticated equipment and stringent high temperature conditions. Given this general applicability, this method holds great promise for exfoliating layered materials that are sensitive to elevated temperature.

Li, Chen; Wang, Tailin; Wu, Yongzhong; Ma, Fukun; Zhao, Gang; Hao, Xiaopeng

2014-12-01

129

An experimental evaluation of thermosiphon solar water heaters with closed loop freeze protection  

NASA Astrophysics Data System (ADS)

The purpose of this research was to examine the performances of two thermosiphon hot water heaters. One system ran a 50-50 ethylene glycol-water solution through a flat plate type collector and a copper coil heat exchanger placed inside the storage tank. The other system is conventional and ran the storage tank water through the collector with open pipes into and out of the storage tank (i.e. no heat exchanger). Obviously the heat exchanger system will perform less efficiently because of higher fluid viscosity and losses in the heat exchanger. But because this system will not freeze, it could be used in winter and doesn't need draining to prevent pipe freezing. The research centered on determining the exact extent of the decrease in efficiency of this type of system from the more conventional type of system. The results showed that the system with the heat exchanger performed, on the average, 9% less efficiently than the system without the heat exchanger. This figure is acceptable and such an ethylene glycol system is recommended for use in winter or when there is a possibility of freezing on cool nights from radiation losses.

Bogart, J.

1980-05-01

130

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

131

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

132

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

2007-11-01

133

Supercooling and freezing processes in nanoconfined water by time-resolved optical Kerr effect spectroscopy  

E-print Network

Using heterodyne-detected optical Kerr effect (HD-OKE) measurements, we investigate the vibrational dynamics and the structural relaxation of water nanoconfined in Vycor porous silica samples (pore size $\\simeq~4~nm$ ) at different levels of hydration and temperatures. At low level of hydration, corresponding to two complete superficial water layers, no freezing occurs and water remains mobile at all the investigated temperatures with dynamic features similar, but not equal, to the bulk water. The fully hydrated sample shows formation of ice at about 248 K, this process does not involve all the contained water; a part of it remains in a supercooled phase. The structural relaxation times measured from the decay of the time-dependent HD-OKE signal shows temperature dependence largely affected by the hydration level; the low frequency ($\

A. Taschin; P. Bartolini; A. Marcelli; R. Righini; R. Torre

2014-08-06

134

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

135

Traveling water waves with point vortices  

E-print Network

We construct small-amplitude solitary traveling gravity-capillary water waves with a finite number of point vortices along a vertical line, on finite depth. This is done using a local bifurcation argument. The properties of the resulting waves are also examined: We find that they depend significantly on the position of the point vortices in the water column.

Kristoffer Varholm

2015-03-20

136

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.

New England Aquarium

2011-01-01

137

The Mpemba effect: When can hot water freeze faster than cold?  

NASA Astrophysics Data System (ADS)

We review the Mpemba effect, where initially hot water freezes faster than initially cold water. Although the effect might appear impossible, it has been observed in numerous experiments and was discussed by Aristotle, Francis Bacon, Roger Bacon, and Descartes. It has a rich and fascinating history, including the story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon is simple to describe and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. Proposed theoretical mechanisms for the Mpemba effect and the results of contemporary experiments on the phenomenon are surveyed. The observation that hot water pipes are more likely to burst than cold water pipes is also discussed.

Jeng, Monwhea

2006-06-01

138

Formation of Martian Gullies by the Flow of Simultaneously Freezing and Boiling Liquid Water  

NASA Technical Reports Server (NTRS)

Geomorphic evidence suggests that recent gullies on Mars were formed by fluvial activity. The Martian gully features are significant because their existence implies the presence of liquid water near the surface on Mars in geologically recent times. Irrespective of the ultimate source of the fluid carving the gullies, we seek to understand the behavior of this fluid after it reaches the Martian surface. We find that, contrary to popular belief, the fluvially-carved Martian gullies require formation conditions such as now occur on Mars, outside of the temperature-pressure stability regime of liquid water. Mars Global Surveyor observations of gully length and our modeling of water stability are consistent with gully formation from the action of pure liquid water that is simultaneously boiling and freezing.

Heldmann, Jennifer L.; Mellon, Michael T.; Toon, Owen B.; Pollard, Wayne H.; Mellon, Michael T.; Pitlick, John; McKay, Christopher P.; Andersen, Dale T.

2004-01-01

139

Immersion freezing of water and aqueous ammonium sulphate 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 0.85-1.0. 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, ?aw, by 0.2703 and 0.2466, respectively. Corresponding heterogeneous 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 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 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. 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.

2013-02-01

140

AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions  

NASA Technical Reports Server (NTRS)

Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures.

Wiegand, C. L. (principal investigator); Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J.

1981-01-01

141

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

E-print Network

An accurate experimental investigation on the Mpemba effect (that is, the freezing of initially hot water before cold one) is carried out, showing that in the adiabatic cooling of water a relevant role is played by supercooling as well as by phase transitions taking place at 6 +/- 1 oC, 3.5 +/- 0.5 oC and 1.3 +/- 0.6 oC, respectively. The last transition, occurring with a non negligible probability of 0.21, has not been detected earlier. Supported by the experimental results achieved, a thorough theoretical analysis of supercooling and such phase transitions, which are interpreted in terms of different ordering of clusters of molecules in water, is given.

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

2007-04-11

142

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

E-print Network

An accurate experimental investigation on the Mpemba effect (that is, the freezing of initially hot water before cold one) is carried out, showing that in the adiabatic cooling of water a relevant role is played by supercooling as well as by phase transitions taking place at 6 +/- 1 oC, 3.5 +/- 0.5 oC and 1.3 +/- 0.6 oC, respectively. The last transition, occurring with a non negligible probability of 0.21, has not been detected earlier. Supported by the experimental results achieved, a thorough theoretical analysis of supercooling and such phase transitions, which are interpreted in terms of different ordering of clusters of molecules in water, is given.

Esposito, S; Somma, L

2007-01-01

143

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

NASA Astrophysics Data System (ADS)

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 non-negligible probability of 0.21 with respect to the total number of runs performed, has not been detected earlier. On the basis of our experimental results, we can present a thorough theoretical analysis of supercooling and of such phase transitions, which are interpreted in terms of the different ordering of molecule clusters in water.

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

2008-02-01

144

Particular points of water-alcohol solutions  

NASA Astrophysics Data System (ADS)

The paper discusses the physical nature of the nontrivial properties of aqueous alcohol solutions in a range of molar concentrations x ˜ 0.05. A particular point is determined based on analysis of the temperature and concentration dependences of contraction, which is the simplest thermodynamic characteristic of solutions. The occurrence of particular points in water-alcohol solutions is shown to be directly related to the structural features of water. The concentration-temperature dependence is plotted, where the contraction behavior of an aqueous ethanol solution demonstrates a structural feature of water. The formulas to find the concentration values at particular points are proposed.

Gotsulskiy, V. Ya.; Malomuzh, N. P.; Chechko, V. E.

2015-02-01

145

HybridICE® filter: ice separation in freeze desalination of mine waste waters.  

PubMed

Freeze desalination is an alternative method for the treatment of mine waste waters. HybridICE(®) technology is a freeze desalination process which generates ice slurry in surface scraper heat exchangers that use R404a as the primary refrigerant. Ice separation from the slurry takes place in the HybridICE filter, a cylindrical unit with a centrally mounted filter element. Principally, the filter module achieves separation of the ice through buoyancy force in a continuous process. The HybridICE filter is a new and economical means of separating ice from the slurry and requires no washing of ice with water. The performance of the filter at a flow-rate of 25 L/min was evaluated over time and with varied evaporating temperature of the refrigerant. Behaviours of the ice fraction and residence time were also investigated. The objective was to find ways to improve the performance of the filter. Results showed that filter performance can be improved by controlling the refrigerant evaporating temperature and eliminating overflow. PMID:24804655

Adeniyi, A; Maree, J P; Mbaya, R K K; Popoola, A P I; Mtombeni, T; Zvinowanda, C M

2014-01-01

146

The influence of residual water on the secondary structure and crystallinity of freeze-dried fibrinogen.  

PubMed

The purpose of this work was to investigate the influence of water content on the secondary structure of a freeze-dried protein (fibrinogen) after a storage period of two weeks. To that end, attenuated reflectance Fourier transformed infrared (ATR-FTIR) and Raman spectra were generated and evaluated and the crystalline state of the fibrinogen bulks was determined via X-ray diffraction. First, a PCA (principal component analysis) of the spectral data was performed. While the ?-helix and ?-turn contents were increasing with the increasing water content, the ?-sheet content was decreasing. A partial least squares (PLS) model was developed to correlate the mid-infrared and Raman spectral changes with the degree of crystallinity. The obtained R(2) value of 0.953 confirmed a correlation between changes in the secondary structure and crystallinity of the samples. The results demonstrated that the combined ATR-FTIR and Raman approach could be used to predict the crystalline state in freeze-dried fibrinogen products. PMID:25701629

Wahl, Verena; Scheibelhofer, Otto; Roessl, Ulrich; Leitgeb, Stefan; De Beer, Thomas; Khinast, Johannes

2015-04-30

147

Does Hot Water Freeze Faster than Cold? Investigation of the Reproducibility and Causes of the Mpemba Effect  

Microsoft Academic Search

An investigation into the reproducibility and possible causes of the Mpemba effect has been performed. The Mpemba effect is the name given to the common observation by non-scientists that hot water appears to freeze faster than cold water.^1 Previous scientific studies of this effect have found conflicting results. These discrepancies appear to be due in part to inconsistent definitions of

Joseph Thomas; Susan Lehman

2008-01-01

148

Freezing a water droplet on an aligned Si nanorod array substrate  

NASA Astrophysics Data System (ADS)

When a water droplet is dried on a vertically aligned Si nanorod array surface, the nanorods are bundled together. To understand how bundles are formed, a water droplet is frozen rapidly on a Si nanorod array surface observed under a cryo-SEM (scanning electron microscope). The nanorods in the precursor film form similar bundles as those dried in air. But the nanorods under the apparent frozen water droplet are only slightly deformed. We propose that the bundling of nanorods is caused by non-uniform water-nanorod interaction, which could happen either during the water spreading or drying process. Therefore, controlling the liquid-nanostructure interaction could minimize the bundling. In addition, the rapid freezing process does not preserve the water inside the nanochannels, and almost all the water forms ice on top of the nanorod surface, either as a planar interface or as particles, depending on the locations. The separated ice-nanorod interface will have potential applications in chemical separation and crystal growth.

Fan, J.-G.; Zhao, Y.-P.

2008-04-01

149

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

150

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

2011-12-14

151

Exploration of Impinging Water Spray Heat Transfer at System Pressures Near the Triple Point  

NASA Technical Reports Server (NTRS)

The heat transfer of a water spray impinging upon a surface in a very low pressure environment is of interest to cooling of space vehicles during launch and re-entry, and to industrial processes where flash evaporation occurs. At very low pressure, the process occurs near the triple point of water, and there exists a transient multiphase transport problem of ice, water and water vapor. At the impingement location, there are three heat transfer mechanisms: evaporation, freezing and sublimation. A preliminary heat transfer model was developed to explore the interaction of these mechanisms at the surface and within the spray.

Golliher, Eric L.; Yao, Shi-Chune

2013-01-01

152

Can Propagation of Gas Bubbles Lead to Detached Solidification? Experiments on Freezing of Water  

E-print Network

Yazhen Wang, Liya L. Regel,* and William R. Wilcox* International Center for Gravity Materials Science the freezing interface influenced gas bubble formation, and was outward for a concave freezing interface an organic compound, naphthalene.20 The formation and behavior of gas bubbles at a freezing interface can

Regel, Liya L.

153

Gas-phase ions produced by freezing water or methanol for analysis using mass spectrometry.  

PubMed

Introducing water or methanol containing a low concentration of volatile or nonvolatile analyte into an inlet tube cooled with dry ice linking atmospheric pressure and the first vacuum stage of a mass spectrometer produces gas-phase ions even of small proteins that can be detected by mass spectrometry. Collision-induced dissociation experiments conducted in the first vacuum region of the mass spectrometer suggest analyte ions being protected by a solvent cage. The charges may be produced by processes similar to those proposed for charge separation under freezing conditions in thunderclouds. By this process, the surface of an ice pellet is charged positive and the interior negative so that removal of surface results in charge separation. A reversal of surface charge is expected for a heated droplet surface, and this is observed by heating rather than cooling the inlet tube. These observations are consistent with charged supercooled droplets or ice particles as intermediates in the production of analyte ions under freezing conditions. PMID:25014489

Pagnotti, Vincent S; Chakrabarty, Shubhashis; Wang, Beixi; Trimpin, Sarah; McEwen, Charles N

2014-08-01

154

Lethal freeze-dehydration injury of dogwood stem tissue does not change the activation energy of water permeability.  

PubMed

The Arrhenius activation energy for water permeability, (DeltaE(a,H(2)O)) through stem cortical tissue of red osier dogwood (Cornus sericea L.) was determined after treatments which cause membrane rupture as well as after a lethal slow freeze and subsequent slow rewarming. The latter value was higher than the former, but was indistinguishable from the DeltaE(a,H(2)O) found for healthy tissue. It was concluded that membrane permeability to water is not altered during the first 24 to 48 hours after exposure of nonacclimated red osier dogwood to lethal freeze dehydration injury. PMID:16661222

Carter, J V; Braden, M

1980-03-01

155

Lethal Freeze-Dehydration Injury of Dogwood Stem Tissue Does Not Change the Activation Energy of Water Permeability 1  

PubMed Central

The Arrhenius activation energy for water permeability, (?Ea,H2O) through stem cortical tissue of red osier dogwood (Cornus sericea L.) was determined after treatments which cause membrane rupture as well as after a lethal slow freeze and subsequent slow rewarming. The latter value was higher than the former, but was indistinguishable from the ?Ea,H2O found for healthy tissue. It was concluded that membrane permeability to water is not altered during the first 24 to 48 hours after exposure of nonacclimated red osier dogwood to lethal freeze dehydration injury. PMID:16661222

Carter, John V.; Braden, Margaret

1980-01-01

156

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

157

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

Microsoft Academic Search

\\u000a Free energy perturbation Monte Carlo (FEP\\/MC) simulations are performed for both the liquid and solid phases of water to determine\\u000a the melting temperature of several popular three and four-site water models. Gibbs free energy vs. temperature plots are constructed\\u000a from the simulations to determine the melting temperature. For the liquid phase, standard FEP\\/MC simulations are used to calculate\\u000a the free

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

158

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

Microsoft Academic Search

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

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

2010-01-01

159

The influence of ionizable and non-ionizable compounds in milk upon its freezing point  

E-print Network

fulfillmeut of tho requireaoais for the degree of MAST@a OP SCIXSCS August 1955 Ma)or Sub)sots Dairp Husbaadry TRX I?PLURKCX OF IOWIKEBLD LSD WOX~IOSISLDLX COMPOOTDS IR MILT UPON ITS FSNIWO POIDT k Thesis By Prank P taker ton ipprovs4 as to style an4... Coat Laotose an4 Coaduotivity. The Iafluenoo of Breed on the Preesiag Point of Milk, Por Coat Laotose aa4 Coaduotivity. The Iaf lessee of Type of Ration Ped to Cows upoa ths Pressing Point, Per Coat Lsotose and Conduotivity of Milk. . . . 13 Patt 1...

Pinkerton, Frank

1955-01-01

160

Fish With Nature's Anti-freeze  

NSDL National Science Digital Library

Using this material, students will discover that under special experimental conditions, fish have been observed functioning in ice-free cold salt water at a temperature of -6 degrees Centigrade. Research has found that these fish have eight types of anti-freeze molecules which bathe the interior surface of their skin, acting as a barrier to ice propagating in from outside. When the anti-freeze molecules are not present, ice filters through their skin at these temperatures and crystallizes (freezes) their blood and tissues. Students will experiment with lowering the freezing point of a substance, thus causing it to remain liquid at a temperature when it is normally solid. Students will compare their findings with facts about Antarctic ice-fish, which have bodily fluids that remain liquid at temperatures below freezing.

161

Compression of cooked freeze-dried carrots  

E-print Network

~ order interactions for the attributes mentioned above. From these ~ interactions and correlation coefficients it is evident that some compromises must be made during processing to obtain a quality freese- ' ~ dried compressed carrot bar. The most... LIST OF FIGURES Figure Page 1 Triple point of water Compressed freeze-dried carrot bars Compression cell 12 13 Score card for sensory evaluation of freeze-dried carrot bars . 17 First order interaction of sugar x moisture and shedding time...

Macphearson, Bruce Alan

1973-01-01

162

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. PMID:16464880

RÄISÄNEN, MIKKO; REPO, TAPANI; LEHTO, TARJA

2006-01-01

163

Water balance in the sugarbeet root maggot, Tetanops myopaeformis, during long-term low-temperature storage and after freezing  

Technology Transfer Automated Retrieval System (TEKTRAN)

The sugarbeet root maggot, Tetanops myopaeformis (Röder), can be stored in moist sand at 4 - 6°C for up to five years and is freeze tolerant. The majority of the stored larvae are in post-diapause quiescence and the rest of the larvae are in a multi-year diapause. The percent body mass of water and ...

164

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

2013-10-01

165

Does Hot Water Freeze Faster than Cold? Investigation of the Reproducibility and Causes of the Mpemba Effect  

NASA Astrophysics Data System (ADS)

An investigation into the reproducibility and possible causes of the Mpemba effect has been performed. The Mpemba effect is the name given to the common observation by non-scientists that hot water appears to freeze faster than cold water.^1 Previous scientific studies of this effect have found conflicting results. These discrepancies appear to be due in part to inconsistent definitions of freezing based on visual observation. We have investigated the Mpemba effect by continuously monitoring the temperature of a container of water to determine the amount of time needed for the water to turn completely to ice, as indicated by the temperature falling below 0 ^oC. We have successfully observed the effect repeatedly and have found it to be dependent on the sample's temperature history rather than the sample temperature when placed into the freezer. Room temperature water which had been briefly heated to 100 ^oC then cooled froze approximately 50 % faster than room temperature water which had not been heated. The effect on the freezing time of increasing or decreasing the amount of dissolved gas in the water will also be discussed. 1. M. Jeng. Am. J. Phys. 74 514 (2006).

Thomas, Joseph; Lehman, Susan

2008-03-01

166

Calorimetric measurement of water transport and intracellular ice formation during freezing in cell suspensions.  

PubMed

The current study presents a new and novel analysis of heat release signatures measured by a differential scanning calorimeter (DSC) associated with water transport (WT), intracellular ice formation (IIF) and extracellular ice formation (EIF). Correlative cryomicroscopy experiments were also performed to validate the DSC data. The DSC and cryomicroscopy experiments were performed on human dermal fibroblast cells (HDFs) at various cytocrit values (0-0.8) at various cooling rates (0.5-250 °C/min). A comparison of the cryomicroscopy experiments with the DSC analysis show reasonable agreement in the water transport (cellular dehydration) and IIF characteristics between both the techniques with the caveat that IIF measured by DSC lagged that measured by cryomicroscopy. This was ascribed to differences in the techniques (i.e. cell vs. bulk measurement) and the possibility that not all IIF is associated with visual darkening. High and low rates of 0.5 °C/min and 250 °C/min were chosen as HDFs did not exhibit significant IIF or WT at each of these extremes respectively. Analysis of post-thaw viability data suggested that 10 °C/min was the presumptive optimal cooling rate for HDFs and was independent of the cytocrit value. The ratio of measured heat values associated with IIF (q(IIF)) to the total heat released from both IIF and water transport or from the total cell water content in the sample (q(CW)) was also found to increase as the cooling rate was increased from 10 to 250 °C/min and was independent of the sample cytocrit value. Taken together, these observations suggest that the proposed analysis is capable of deconvolving water transport and IIF data from the measured DSC latent heat thermograms in cell suspensions during freezing. PMID:22863747

Mori, Shoji; Choi, Jeunghwan; Devireddy, Ram V; Bischof, John C

2012-12-01

167

Universality of Tip Singularity Formation in Freezing Water Drops A.G. Marin1  

E-print Network

immersed in a cooling bath of ethylene-glycol, ethanol and dry ice. (b) The shape of the advancing freezing solidification for freeze drying purposes [8], and in recent studies on supercooling [9] and icing of substrates- alistic when numerically treating the solidification dy- cooling bath copper plate capillary a) Hele

Snoeijer, Jacco

168

Control of crystal growth in water purification by directional freeze crystallization  

NASA Technical Reports Server (NTRS)

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

Conlon, William M. (Inventor)

1996-01-01

169

Freezing in confined geometries  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

170

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

171

Xylem embolism in response to freeze-thaw cycles and water stress in ring-porous, diffuse-porous, and conifer species.  

PubMed

Vulnerability to xylem embolism by freeze-thaw cycles and water stress was quantified in ring-porous (Quercus gambelii Nutt.), diffuse-porous (Populus tremuloides Michx., Betula occidentalis Hook.), and conifer species (Abies lasiocarpa Nutt., Juniperus scopulorum Sarg.). Embolism was measured by its reduction of xylem hydraulic conductivity; it was induced by xylem tension (water-stress response) and by a tension plus a freeze-thaw cycle (freeze response). Conifers showed little (Juniperus) or no (Abies) freeze response even to repeated cycles. In contrast, Quercus embolized more than 90% by freezing at tensions below 0.2 MPa, whereas similar embolism without freezing required tensions above 4.5 MPa. Diffuse-porous trees (Betula, Populus) showed an intermediate freeze response. The magnitude of the freeze response was correlated with conduit volume but occurred at higher tensions than predicted from theory. Large early-wood vessels (2.8 x 10(-9) m(3)) in oak were most vulnerable to embolism by freezing, small vessels in Populus and Betula were intermediate (approximately 7 x 10(-11) m(3)), and tracheids in conifers (about 3 x 10(-13) m(3)) were most resistant. The same trend was found within a stem: embolism by freeze-thawing occurred preferentially in wider conduits. The water-stress response was not correlated with conduit volume; previous work indicates it is a function of interconduit pit membrane structure. Native embolism levels during winter corroborated laboratory results on freezing: Quercus embolized 95% with the first fall freeze, Populus and Betula showed gradual increases to more than 90% embolism by winter's end, and Abies remained below 30%. PMID:16653035

Sperry, J S; Sullivan, J E

1992-10-01

172

Xylem Embolism in Response to Freeze-Thaw Cycles and Water Stress in Ring-Porous, Diffuse-Porous, and Conifer Species 1  

PubMed Central

Vulnerability to xylem embolism by freeze-thaw cycles and water stress was quantified in ring-porous (Quercus gambelii Nutt.), diffuse-porous (Populus tremuloides Michx., Betula occidentalis Hook.), and conifer species (Abies lasiocarpa Nutt., Juniperus scopulorum Sarg.). Embolism was measured by its reduction of xylem hydraulic conductivity; it was induced by xylem tension (water-stress response) and by a tension plus a freeze-thaw cycle (freeze response). Conifers showed little (Juniperus) or no (Abies) freeze response even to repeated cycles. In contrast, Quercus embolized more than 90% by freezing at tensions below 0.2 MPa, whereas similar embolism without freezing required tensions above 4.5 MPa. Diffuse-porous trees (Betula, Populus) showed an intermediate freeze response. The magnitude of the freeze response was correlated with conduit volume but occurred at higher tensions than predicted from theory. Large early-wood vessels (2.8 × 10?9 m3) in oak were most vulnerable to embolism by freezing, small vessels in Populus and Betula were intermediate (approximately 7 × 10?11 m3), and tracheids in conifers (about 3 × 10?13 m3) were most resistant. The same trend was found within a stem: embolism by freeze-thawing occurred preferentially in wider conduits. The water-stress response was not correlated with conduit volume; previous work indicates it is a function of interconduit pit membrane structure. Native embolism levels during winter corroborated laboratory results on freezing: Quercus embolized 95% with the first fall freeze, Populus and Betula showed gradual increases to more than 90% embolism by winter's end, and Abies remained below 30%. PMID:16653035

Sperry, John S.; Sullivan, June E. M.

1992-01-01

173

Prediction of heat capacity, density and freezing point of liquid refrigerant solutions using an excess Gibbs energy model  

Microsoft Academic Search

Immersion chilling and freezing (ICF) of foods use aqueous solutions at low temperature that are considered secondary refrigerants. These solutions contain solutes such as NaCl, CaCl2, KCl, ethanol, glucose, etc. The ICF processes have several advantages over the conventional food chilling and freezing methods. The aim of this work was to study the behavior of an excess Gibbs energy model

Juan M. Peralta; Amelia C. Rubiolo; Susana E. Zorrilla

2007-01-01

174

Modeling of flow and solidification of liquid water during unidirectional freezing in porous media  

NASA Astrophysics Data System (ADS)

Flow and phase change of liquid in porous media are fundamental processes in earth science and soil physics. Particularly in cold region or periglacial environment, the flow and solidification of pore water in the ground simultaneously occur and their collective interactions control the growth of ice lenses and upward displacement of surface called as frost heave. In the nucleation and growth of ice lenses, the homogeneous mixture of soil particles and pore water is transformed to the heterogeneous structure due to the water redistribution and the particle migration. Unfrozen water that is adsorbed to the particle surface or confined to capillary regions plays an important role in the formation of ice lenses and its behaviors have been investigated from a perspective of premelting dynamics (e.g., Worster and Wettlaufer 2006). In the porous media below the nominal melting temperature, intermolecular forces that act between particles and ice through the liquid thin film produce the net thermomolecular force that is responsible for the particle separation form the ice lenses(Dash et al. 2006). Although the mechanisms of ice lens formation have been investigated by many researchers, still large uncertainties remain and more experimental constraints are required. Here we present experimental results of ice lens formation, particularly focusing on the role of grain size and compare the model by Rempel et al (2004). We have performed the unidirectional freezing experiments using water-saturated glass beads that have uniform structures. Since the flow of water in porous media depends on the particles size and pore throat size (Darcy's law), we have prepared various sizes of glass beads from submicron to submillimeter. Our experiments reveal the clear relationships between the host particle sizes and nucleated location and lens thickness. Part of this work is already published in Saruya et al, PRE but we extended to smaller sized regime. We compared our experimental results to the numerical predictions that were modified to our experimental conditions based upon Rempel et al. (2004). The comparison between the experimental results and numerical predictions emphasizes the importance of kinetics due to the flow in liquid thin film and implies the kind of dominant van der Waals interactions that controls the behavior of liquid thin film.

Saruya, Tomotaka; Rempel, Alan; Kurita, Kei

2014-05-01

175

Considerations for osmolality measurement under elevated pCO(2): comparison of vapor pressure and freezing point osmometry.  

PubMed

Osmolality increases with pCO(2) in bioreactors with pH control, and it has been shown that osmolality compensation by decreasing the basal NaCl concentration partially mitigates the adverse effects of elevated pCO(2) on animal cell growth, protein production, and glycosylation. Thus, measurement of osmolality is important for a complete characterization of the culture environment under elevated pCO(2). However, osmolality measurement may be compromised by CO(2) evolution. Freezing point depression and vapor pressure depression osmometry were directly compared for the measurement of osmolality in samples at elevated pCO(2) (up to 250 mmHg) and at a variety of pH values (6.7-7.5). More extensive degassing may be expected with the vapor pressure osmometer due to the smaller sample volume and larger surface area employed. However, both types of osmometer yielded similar results for all pCO(2) and pH values studied. Moreover, the measured values agreed with osmolality values calculated using a semi-empirical model. Further analysis showed that, while sample degassing may result in a large decrease in pCO(2), there is little associated decrease in osmolality. The great majority of total CO(2) in solution is present as bicarbonate (HCO(3)(-)). Although a small amount of HCO(3)(-) is converted to CO(2) to compensate for CO(2) evolution, further depletion of HCO(3)(-) is inhibited by the associated increase in medium pH and by the need for HCO(3)(-) to maintain charge neutrality in solution. This explanation is consistent with the observed similarity in osmolality values for the two types of osmometer. It was also observed that osmolality did not change in samples that were frozen at -20 degrees C for up to 1 year. PMID:10592516

Schmelzer, A E; deZengotita, V M; Miller, W M

2000-01-20

176

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

177

Freezing points and enthalpies of dilution of aqueous formic, acetic, propionic, and butyric acids. Free energies and enthalpies of solute—Solute interactions  

Microsoft Academic Search

Freezing-point depressions and enthalpies of dilution for aqueous solutions of the straight chain, aliphatic carboxylic acids, C1 through C4, have been measured. These data, together with the corresponding apparent molal heat capacities, have been used to calculate the pairwise free energy and enthalpy of interaction of undissociated acid molecules at 298.150K. As expected, the effect of dimer and triplet interaction

Alexander L. Harris; Peter T. Thompson; Robert H. Wood

1980-01-01

178

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. Calculation…

Mills, Allan

2010-01-01

179

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

180

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

181

Subzero water permeability parameters and optimal freezing rates for sperm cells of the southern platyfish, Xiphophorus maculatus.  

PubMed

This study reports the subzero water transport characteristics (and empirically determined optimal rates for freezing) of sperm cells of live-bearing fishes of the genus Xiphophorus, specifically those of the southern platyfish Xiphophorus maculatus. These fishes are valuable models for biomedical research and are commercially raised as ornamental fish for use in aquariums. Water transport during freezing of X. maculatus sperm cell suspensions was obtained using a shape-independent differential scanning calorimeter technique in the presence of extracellular ice at a cooling rate of 20 degrees C/min in three different media: (1) Hanks' balanced salt solution (HBSS) without cryoprotective agents (CPAs); (2) HBSS with 14% (v/v) glycerol, and (3) HBSS with 10% (v/v) dimethyl sulfoxide (DMSO). The sperm cell was modeled as a cylinder with a length of 52.35 microm and a diameter of 0.66 microm with an osmotically inactive cell volume (Vb) of 0.6 V0, where V0 is the isotonic or initial cell volume. This translates to a surface area, SA to initial water volume, WV ratio of 15.15 microm(-1). By fitting a model of water transport to the experimentally determined volumetric shrinkage data, the best fit membrane permeability parameters (reference membrane permeability to water at 0 degrees C, Lpg or Lpg [cpa] and the activation energy, E(Lp) or E(Lp) [cpa]) were found to range from: Lpg or Lpg [cpa] = 0.0053-0.0093 microm/minatm; E(Lp) or E(Lp) [cpa] = 9.79-29.00 kcal/mol. By incorporating these membrane permeability parameters in a recently developed generic optimal cooling rate equation (optimal cooling rate, [Formula: see text] where the units of B(opt) are degrees C/min, E(Lp) or E(Lp) [cpa] are kcal/mol, L(pg) or L(pg) [cpa] are microm/minatm and SA/WV are microm(-1)), we determined the optimal rates of freezing X. maculatus sperm cells to be 28 degrees C/min (in HBSS), 47 degrees C/min (in HBSS+14% glycerol) and 36 degrees C/min (in HBSS+10% DMSO). Preliminary empirical experiments suggest that the optimal rate of freezing X. maculatus sperm in the presence of 14% glycerol to be approximately 25 degrees C/min. Possible reasons for the observed discrepancy between the theoretically predicted and experimentally determined optimal rates of freezing X. maculatus sperm cells are discussed. PMID:15925577

Pinisetty, D; Huang, C; Dong, Q; Tiersch, T R; Devireddy, R V

2005-06-01

182

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

183

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

184

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 and ?aw by 0.2703 and 0.2466, respectively. Corresponding heterogeneous ice nucleation rate coefficients, Jhet, are (9.6×2.5)x104 and (5.4×1.4)x104 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.; Alpert, P. A.; Knopf, D. A.

2013-12-01

185

Classical nucleation theory of homogeneous freezing of water: thermodynamic and kinetic parameters.  

PubMed

The probability of homogeneous ice nucleation under a set of ambient conditions can be described by nucleation rates using the theoretical framework of Classical Nucleation Theory (CNT). This framework consists of kinetic and thermodynamic parameters, of which three are not well-defined (namely the interfacial tension between ice and water, the activation energy and the prefactor), so that any CNT-based parameterization of homogeneous ice formation is less well-constrained than desired for modeling applications. Different approaches to estimate the thermodynamic and kinetic parameters of CNT are reviewed in this paper and the sensitivity of the calculated nucleation rate to the choice of parameters is investigated. We show that nucleation rates are very sensitive to this choice. The sensitivity is governed by one parameter - the interfacial tension between ice and water, which determines the energetic barrier of the nucleation process. The calculated nucleation rate can differ by more than 25 orders of magnitude depending on the choice of parameterization for this parameter. The second most important parameter is the activation energy of the nucleation process. It can lead to a variation of 16 orders of magnitude. By estimating the nucleation rate from a collection of droplet freezing experiments from the literature, the dependence of these two parameters on temperature is narrowed down. It can be seen that the temperature behavior of these two parameters assumed in the literature does not match with the predicted nucleation rates from the fit in most cases. Moreover a comparison of all possible combinations of theoretical parameterizations of the dominant two free parameters shows that one combination fits the fitted nucleation rates best, which is a description of the interfacial tension coming from a molecular model [Reinhardt and Doye, J. Chem. Phys., 2013, 139, 096102] in combination with the activation energy derived from self-diffusion measurements [Zobrist et al., J. Phys. Chem. C, 2007, 111, 2149]. However, some fundamental understanding of the processes is still missing. Further research in future might help to tackle this problem. The most important questions, which need to be answered to constrain CNT, are raised in this study. PMID:25627933

Ickes, Luisa; Welti, André; Hoose, Corinna; Lohmann, Ulrike

2015-02-10

186

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

187

Homogeneous ice nucleation from aqueous inorganic/organic particles representative of biomass burning: water activity, freezing temperatures, nucleation rates.  

PubMed

Homogeneous ice nucleation plays an important role in the formation of cirrus clouds with subsequent effects on the global radiative budget. Here we report on homogeneous ice nucleation temperatures and corresponding nucleation rate coefficients of aqueous droplets serving as surrogates of biomass burning aerosol. Micrometer-sized (NH(4))(2)SO(4)/levoglucosan droplets with mass ratios of 10:1, 1:1, 1:5, and 1:10 and aqueous multicomponent organic droplets with and without (NH(4))(2)SO(4) under typical tropospheric temperatures and relative humidities are investigated experimentally using a droplet conditioning and ice nucleation apparatus coupled to an optical microscope with image analysis. Homogeneous freezing was determined as a function of temperature and water activity, a(w), which was set at droplet preparation conditions. The ice nucleation data indicate that minor addition of (NH(4))(2)SO(4) to the aqueous organic droplets renders the temperature dependency of water activity negligible in contrast to the case of aqueous organic solution droplets. The mean homogeneous ice nucleation rate coefficient derived from 8 different aqueous droplet compositions with average diameters of ?60 ?m for temperatures as low as 195 K and a(w) of 0.82-1 is 2.18 × 10(6) cm(-3) s(-1). The experimentally derived freezing temperatures and homogeneous ice nucleation rate coefficients are in agreement with predictions of the water activity-based homogeneous ice nucleation theory when taking predictive uncertainties into account. However, the presented ice nucleation data indicate that the water activity-based homogeneous ice nucleation theory overpredicts the freezing temperatures by up to 3 K and corresponding ice nucleation rate coefficients by up to ?2 orders of magnitude. A shift of 0.01 in a(w), which is well within the uncertainty of typical field and laboratory relative humidity measurements, brings experimental and predicted freezing temperatures and homogeneous ice nucleation rate coefficients into agreement. The experimentally derived ice nucleation data are applied to constrain the water activity-based homogeneous ice nucleation theory to smaller than ±1 order of magnitude compared to the predictive uncertainty of larger than ±6 orders of magnitude. The atmospheric implications of these findings are discussed. PMID:21235213

Knopf, Daniel A; Rigg, Yannick J

2011-02-10

188

Avoidance and tolerance of freezing in ectothermic vertebrates.  

PubMed

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

Costanzo, Jon P; Lee, Richard E

2013-06-01

189

Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [south Texas  

NASA Technical Reports Server (NTRS)

Emissive and reflective data for 10 days, and IR data for 6 nights in south Texas scenes were analyzed after procedures were developed for removing cloud-affected data. HCMM radiometric temperatures were: within 2 C of dewpoint temperatures on nights when air temperature approached dewpoint temperatures; significantly correlated with variables important in evapotranspiration; and, related to freeze severity and planting depth soil temperatures. Vegetation greenness indexes calculated from visible and reflective IR bands of NOAA-6 to -9 meteorological satellites will be useful in the AgRISTARS program for seasonal crop development, crop condition, and drought applications.

Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (principal investigators)

1981-01-01

190

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

191

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

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 subfreezing 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. During the reporting period of 1/1/94 to 3/31/94, project research concentrated on Subtasks 2.0 (Task 2 Project Reporting) and 2.1 (Laboratory-scale FTE Simulations) . The objectives of Task 2 are to conduct laboratory- and bench-scale simulations for optimizing the design of the FTE process. Task 2 requires completion of six subtasks: Subtask 2.0 - Task 2 Project Reporting (initiated 3/1/93), Subtask 2.1 - Laboratory-scale FTE Simulations, Subtask 2.2 Re-evaluation of Process Economics Based on Laboratory-scale Process Simulation Results, Subtask 2.3 - Bench-scale FTE Simulations, Subtask 2.4 - Economic Assessment of Bench-scale Simulations, and Subtask 2.5 - Technical Report of Task 2. The construction, shakedown, and operation of the laboratory-scale process simulations planned were planned for this quarter (Subtask 2.1).

Boysen, J.; Morotti, J.

1994-04-01

192

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

NASA Technical Reports Server (NTRS)

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.

1987-01-01

193

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

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 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...

2014-07-01

194

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 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...

2011-07-01

195

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 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...

2012-07-01

196

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

197

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

198

Strategies for exploration of freeze responsive gene expression: advances in vertebrate freeze toleranceq  

Microsoft Academic Search

Winter survival for many cold-blooded species involves freeze tolerance, the capacity to endure the freezing of a high percentage of total body water as extracellular ice. The wood frog (Rana sylvatica) is the primary model animal used for studies of vertebrate freeze tolerance and current studies in my lab are focused on the freeze-induced changes in gene expression that support

Kenneth B. Storey

199

On the freezing process of sea water from data of laboratory measurements based on nuclear magnetic resonance  

NASA Astrophysics Data System (ADS)

Results of measurements of the relative brine content ( Q m ) and proton magnetic relaxation time ( T 1) in the liquid phase of freezing sea water at temperatures between -2°C and -43°C are given for variable directions of temperature changes using different pulse and stationary methods of NMR. The results are compared with current published evidence. The results of the temperature dependences of Q m at adding NaCl in sea water are shown. In all the cases, the hysteresis loops in the temperature dependencies of Q m and T 1 in brine were discovered. They correspond to the crystallization range of the main salt of sea water (NaCl), which partially precipitates in the crystalline hydrate form (NaCl · 2H2O) at temperatures lower than -23°C. We demonstrate that crystalline hydrates begin to form in brine after complete salvatation of the ions of basic sea water salts at salinity from 85 to 90‰ and temperatures from -5 to -6°C. The determinations of Q m allowed us to calculate the salinity of brine, which agreed well with the current published estimates.

Melnichenko, N. A.; Stunzhas, P. A.

2014-11-01

200

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

201

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

NASA Technical Reports Server (NTRS)

A non-toxic, non-flammable, low-freezing heat transfer fluid is being developed for drop-in replacement within current and future heat transfer loops currently using water or alcohol-based coolants. Numerous water-soluble compounds were down-selected and screened for toxicological, physical, chemical, compatibility, thermodynamic, and heat transfer properties. Two fluids were developed, one with a freezing point near 0 C, and one with a suppressed freezing point. Both fluids contain an additive package to improve material compatibility and microbial resistance. The optimized sub-zero solution had a freezing point of 30 C, and a freezing volume expansion of 10-percent of water. The toxicity of the solutions was experimentally determined as LD(50) greater than 5g/kg. The solutions were found to produce minimal corrosion with materials identified by NASA as potentially existing in secondary cooling loops. Thermal/hydrodynamic performance exceeded that of glycol-based fluids with comparable freezing points for temperatures Tf greater than 20 C. The additive package was demonstrated as a buffering agent to compensate for CO2 absorption, and to prevent microbial growth. The optimized solutions were determined to have physically/chemically stable shelf lives for freeze/thaw cycles and longterm test loop tests.

Cutbirth, J. Michael

2012-01-01

202

Salting out of alcohols by alkali halides at the freezing temperature  

Microsoft Academic Search

The freezing-point depression of the ternary systems water-alkali halidesalcohols was measured with a precision Advanced Instrument osmometer. From the corresponding freezing-point depression of the binary systems the salting-out constantsks were calculated. The effect of ionic size was investigated withtert-butanol, and the effect of alcohol chain length with NaCl. The trends ofks with ionic size are similar to those of typical

Jacques E. Desnoyers; Michel Billon; Sylvain Léger; Gérald Perron; Jean-Pierre Morel

1976-01-01

203

WASTEWATER IN RECEIVING WATERS AT WATER SUPPLY ABSTRACTION POINTS  

EPA Science Inventory

The purpose of this project was to determine how much wastewater and wastewater-derived material from discharges is present in the surface water supplies of U.S. cities of over 25,000 population. The study identifies 1246 municipal water supply utilities using surface water from ...

204

Modelling Water Flow, Heat Transport, Soil Freezing and Thawing, and Snow Processes in a Clayey, Subsurface Drained Agricultural Field  

NASA Astrophysics Data System (ADS)

Simulation of hydrological processes for the purposes of agricultural water management and protection in boreal environment requires description of winter time processes, including heat transport, soil freezing and thawing, and snow accumulation and melt. Finland is located north of the latitude of 60 degrees and has one third to one fourth of the total agricultural land area (2.3 milj. ha) on clay soils (> 30% of clay). Most of the clayey fields are subsurface drained to provide efficient drainage and to enable heavy machines to operate on the fields as soon as possible after the spring snowmelt. Generation of drainflow and surface runoff in cultivated fields leads to nutrient and sediment load, which forms the major share of the total load reaching surface waters at the national level. Water, suspended sediment, and soluble nutrients on clayey field surface are conveyed through the soil profile to the subsurface drains via macropore pathways as the clayey soil matrix is almost impermeable. The objective of the study was to develop the missing winter related processes into the FLUSH model, including soil heat transport, snow pack simulation and the effects of soil freezing and thawing on the soil hydraulic conductivity. FLUSH is an open source (MIT license), distributed, process-based model designed to simulate surface runoff and drainflow in clayey, subsurface drained agricultural fields. 2-D overland flow is described with the diffuse wave approximation of the Saint Venant equations and 3-D subsurface flow with a dual-permeability model. Both macropores and soil matrix are simulated with the Richards equation. Soil heat transport is described with a modified 3-D convection-diffusion equation. Runoff and groundwater data was available from different periods from January 1994 to April 1999 measured in a clayey, subsurface drained field section (3.6 ha) in southern Finland. Soil temperature data was collected in two locations (to a depth of 0.8 m) next to the experimental field section while snow and frost depths were recorded within the experimental field section. The model was calibrated with 1994 data and validated with soil temperature and snow and frost depth data from the years 1995-1999. The main advantage of the new model was the 3-D distributed nature of the system which made it possible to simulate lateral water and heat fluxes in soil and overland flow on the field surface. Also, the possibility to simulate hydrological conditions in the experimental field continuously from 1994 to 1998 was essential because the main sediment loads in Nordic fields usually occur after snow melt and during autumn rains and the resulting runoff depends on the antecedent moisture conditions in the field. The simulation results revealed differences in soil temperatures within the field area due to the topography of the undulating field. The low lying areas were colder (up to 1 °C) during winter and also remained colder longer in the spring due to the higher water content compared to the drier, upper parts of the slopes. Repeated freezing and thawing cycles during the winter and early spring caused an ice layer to form on the soil surface which promoted generation of surface runoff. The snow cover over the field and the organic matter in the tillage layer had an insulating effect on the soil temperatures.

Warsta, L.; Turunen, M.; Koivusalo, H. J.; Paasonen-Kivekäs, M.; Karvonen, T.; Taskinen, A.

2012-12-01

205

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

206

Modeling Soil Freezing Dynamics  

Microsoft Academic Search

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 permeability of the soil. This is aggravated by the tendency of water

G. N. Flerchinger; M. S. Seyfried; S. P. Hardegree

2002-01-01

207

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

NASA Astrophysics Data System (ADS)

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

Hamidi, Nurkholis; Tsuruta, Takaharu

208

Freezing and melting behavior of an octyl ?-D-glucoside-water binary system--inhibitory effect of octyl ?-D-glucoside on ice crystal formation.  

PubMed

Phase transition behavior of lyotropic liquid crystals of an octyl ?-D-glucoside (OG)-water binary system during ice freezing and melting was studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Not the thermotropic, but the lyotropic phase transition due to the change of OG concentration during ice freezing and melting was observed. The concentration-temperature phase diagram of the binary system was constructed. Melting temperature of ice, T(m), lyotropic phase transition temperature, T(tr), and glass transition temperatures of unfrozen phases in the absence and presence of ice, T(g) and T(g)', were shown in the phase diagram. The phase diagram indicated that the OG aqueous system was concentrated to ca. 90-92 wt% by ice freezing and exhibited glass transition at T(g)'. An observation of the concentration-gradient specimen by the cryo-POM showed the evidence of the inhibitory effects of OG on nucleation and growth of ice crystals in the extremely high OG concentration system in which the lamellar liquid crystalline phase was formed. This study provided the importance of the influence of concentration change by ice freezing on the behaviour of the sugar-based surfactant-water system under low temperature conditions. PMID:23133837

Ogawa, Shigesaburo; Asakura, Kouichi; Osanai, Shuichi

2012-12-21

209

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

210

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

NASA Technical Reports Server (NTRS)

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

Albright, A. E.

1984-01-01

211

Homogeneous condensation - Freezing nucleation rate measurements for small water droplets in an expansion cloud chamber  

NASA Technical Reports Server (NTRS)

Experimental data on ice nucleation, presented in an earlier paper, are analyzed to yield information about the homogeneous nucleation rate of ice from supercooled liquid and the heights of energy barriers to that nucleation. The experiment consisted of using an expansion cloud chamber to nucleate from the vapor a cloud of supercooled pure water drops and the observation of the fraction of drops which subsequently froze. The analysis employed standard classical homogeneous nucleation theory. The data are used to extract the first experimental measurement (albeit indirect) of the activation energy for the transfer of a water molecule across the liquid-ice interface at temperatures near -40 C. The results provide further evidence that the local liquid structure becomes more icelike as the temperature is lowered.

Hagen, D. E.; Anderson, R. J.; Kassner, J. L., Jr.

1981-01-01

212

Modeling the effect of antecedent soil water storage on water and heat status in seasonally freezing and thawing agricultural soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Taking Hetao Irrigation District of Inner Mongolia's agricultural production as a background and based on field observation data and field measured meteorological data, the influence of antecedent soil water storage (ASWS) on water and heat conditions was simulated and analyzed using the SHAW model ...

213

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

214

Photon point source buildup factors for air, water, and iron  

Microsoft Academic Search

Buildup factors for photons in infinite homogeneous samples of air, water, and iron have been calculated by a moments method code. The photons were assumed to be emitted from a point source. Comparisons of these results to values obtained earlier, both by experiment and by calculation, show reasonable agreement except in some instances of deep penetration. The parameters in the

H. B. Chilton; C. M. Eisenhauer; G. L. Simmons

1980-01-01

215

Freezing points and enthalpies of dilute aqueous solutions of tetrahydropyran, 1,3-dioxane, 1,4-dioxane, and 1,3,5-trioxane. Free energies and enthalpies of solute-solute interactions  

Microsoft Academic Search

The enthalpies of dilute aqueous solutions of tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 1,2,5-trioxane, and an equimolal mixture of tetrahydropyran and 1,3,5-trioxane were measured at 25°C and at molalities from about 0.1 to 1.0 mol kg1. The freezing points of the same aqueous solutions (except for 1,3-dioxane) were measured over a similar molality range. The results were used to calculate the enthalpies and

Byron Y. Okamoto; Robert H. Wood; Jacques E. Desnoyers; Gérald Perron; Lyne Delorme

1981-01-01

216

Freezing Cleans Water  

NSDL National Science Digital Library

This site helps to describe the technology of Snowfluent, a product which atomizes wastewater and sprays it into the air at cold temperatures. The article addresses the potential uses for this technology and also discusses the studies behind the development of Snowfluent.

217

Freeze Technology for Nuclear Applications - 13590  

SciTech Connect

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

Rostmark, Susanne C.; Knutsson, Sven [Lulea University of Technology (Sweden)] [Lulea University of Technology (Sweden); Lindberg, Maria [Studsvik Nuclear AB, 611 82 Nykoeping (Sweden)] [Studsvik Nuclear AB, 611 82 Nykoeping (Sweden)

2013-07-01

218

Efflux of Red Cell Water into Buffered Hypertonic Solutions  

Microsoft Academic Search

Buffered NaCI solutions hypertonic to rabbit serum were prepared and freezing point depressions of each determined after dilution with measured amounts of water. Freezing point depression of these dilutions was a linear function of the amount of water added. One ml. of rabbit red cells was added to each 4 ml. of the hypertonic solutions and after incubation at 38°C.

EDWIN G. OLMSTEAD

1960-01-01

219

Lidar point density analysis: implications for identifying water bodies  

USGS Publications Warehouse

Most airborne topographic light detection and ranging (lidar) systems operate within the near-infrared spectrum. Laser pulses from these systems frequently are absorbed by water and therefore do not generate reflected returns on water bodies in the resulting void regions within the lidar point cloud. Thus, an analysis of lidar voids has implications for identifying water bodies. Data analysis techniques to detect reduced lidar return densities were evaluated for test sites in Blackhawk County, Iowa, and Beltrami County, Minnesota, to delineate contiguous areas that have few or no lidar returns. Results from this study indicated a 5-meter radius moving window with fewer than 23 returns (28 percent of the moving window) was sufficient for delineating void regions. Techniques to provide elevation values for void regions to flatten water features and to force channel flow in the downstream direction also are presented.

Worstell, Bruce B.; Poppenga, Sandra; Evans, Gayla A.; Prince, Sandra

2014-01-01

220

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

2011-12-01

221

Water Electrolyzers and the Zero-Point Energy  

NASA Astrophysics Data System (ADS)

The gas emitted from popular water electrolyzer projects manifests unusual energetic anomalies, which include vaporizing tungsten when used in a welding torch and running internal combustion engines on small quantities of the gas. Some claim to run generators in closed loop fashion solely on the gas from the electrolyzer, which is powered solely from the generator. Most investigators believe the energy is from burning hydrogen. A hypothesis is proposed that the dominant energy is not coming from hydrogen, but rather it is coming from charged water gas clusters, which activate and coherently trap zero-point energy.

King, M. B.

222

GEOtop 2.0: simulating the combined energy and water balance at and below the land surface accounting for soil freezing, snow cover and terrain effects  

NASA Astrophysics Data System (ADS)

GEOtop is a fine-scale grid-based simulator that represents the heat and water budgets at and below the soil surface. It describes the three-dimensional water flow in the soil and the energy exchange with the atmosphere, considering the radiative and turbulent fluxes. Furthermore, it reproduces the highly non-linear interactions between the water and energy balance during soil freezing and thawing, and simulates the temporal evolution of the water and energy budgets in the snow cover and their effect on soil temperature. Here, we present the core components of GEOtop 2.0 and demonstrate its functioning. Based on a synthetic simulation, we show that the interaction of processes represented in GEOtop 2.0 can result in phenomena that are significant and relevant for applications involving permafrost and seasonally frozen soils, both in high altitude and latitude regions.

Endrizzi, S.; Gruber, S.; Dall'Amico, M.; Rigon, R.

2014-12-01

223

Particle-size dependence of immersion freezing: Investigation of INUIT test aerosol particles with freely suspended water drops.  

NASA Astrophysics Data System (ADS)

One goal of the research group INUIT (Ice Nuclei research UnIT) is to investigate the efficiencies of several test ice nuclei under comparable conditions but with different experimental techniques. In the present studies, two methods are used: the Mainz vertical wind tunnel and an acoustic levitator placed inside a cold chamber. In both cases drops are freely levitated, either at their terminal velocity in the wind tunnel updraft or around the nodes of a standing ultrasonic wave in the acoustic levitator. Thus, heat transfer conditions are well approximated, and wall contact effects on freezing as well as electrical charges of the drops are avoided. Drop radii are 370 ?m and 1 mm, respectively. In the wind tunnel, drops are investigated at constant temperatures within a certain time period and the onset of freezing is observed directly. In the acoustic levitator, the drop temperature decreases during the experiments and is measured by an in-situ calibrated Infrared thermometer. The onset of freezing is indicated by a rapid rise of the drop surface temperature because of the release of latent heat. Investigated test ice nuclei are Snomax® as a proxy of biological particles and illite NX as well as K-feldspar as represents of mineral dust. The particle concentrations are 1 × 10-12 to 3 × 10-6 g Snomax® per drop and 5 × 10-9 to 5 × 10-5 g mineral dust per drop. Freezing temperatures are between -2 and -18° C in case of Snomax® and between -14 and -26° C in case of mineral dust. The lower the particle masses per drop the lower are the freezing temperatures. For similar particle concentrations in the drops, the median freezing temperatures determined by the two techniques agree well within the measurement errors. With the knowledge of the specific particle surface area of the mineral dusts, the results are interpreted also in terms of particle surface area per drop. Results from the wind tunnel experiments which are performed at constant temperatures indicate that the freezing times are shorter the lower the temperatures are. For evaluation and comparisons of the data, two models of heterogeneous freezing are applied, the stochastic and the time-independent singular description. The nucleation rate coefficients J(T) as well as the surface densities of active sites ns(T) or the numbers of active sites nm(T) are determined from the experimental data. It is shown that both models are suited to describe the present heterogeneous freezing results for the range of investigated particle masses or surface areas per drop. The comparison of the results from the two experimental techniques evaluated with the time-independent singular model indicates an excellent agreement within the measurement errors.

Diehl, Karoline; Debertshäuser, Michael; Eppers, Oliver; Jantsch, Evelyn; Mitra, Subir K.

2014-05-01

224

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

225

Freezing of a Liquid Marble  

E-print Network

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

Ali Hashmi; Adam Strauss; Jie Xu

2012-07-03

226

Aqueous-phase photoproduction of hydrogen peroxide in authentic cloud waters: Wavelength dependence, and the effects of filtration and freeze-thaw cycles  

NASA Astrophysics Data System (ADS)

Quantum yields ( ??) of hydrogen peroxide (HOOH) photoproduction are reported at 313, 334, and 366 nm for authentic cloud waters collected over a three-year period (1991-1993) at Whiteface Mountain, New York. Quantum yields of HOOH production (based on the total sample absorbance) in these cloud waters ranged up to 0.014. For each sample the HOOH quantum yield decreased with increasing wavelength: ?313 > ?334 > ?366. Action spectra for HOOH photoproduction in these cloud waters indicate that light between 290 and 380 nm is primarily responsible for the aqueous-phase HOOH photoproduction in tropospheric water drops. Quantum yields at 334 and 366 nm were each highly correlated with quantum yields at 313 nm. The cloud water absorbances per centimeter at 334 and 313 nm were also highly correlated. This suggests that similar classes; of chromophores were responsible for the aqueous-phase HOOH photoformation in the cloud waters from different events over a three-year period. The chromophores have not been identified, thus absolute quantum yields for HOOH formation from specific chromophores in an authentic sample could not be calculated. Comparisons of wavelength-dependent relative quantum yields in a given authentic cloud water sample (assuming Fe(oxalate) 2- was the primary source of HOOH) with those for Fe(oxalate) 2- in well-defined aqueous systems indicate that photolysis of Fe(oxalate) 2- was not the primary source of HOOH photoproduction in any of the nine authentic cloud water samples studied. Filtration (0.5 ?m Teflon) caused only small differences (?15% increase) in rates of HOOH photoformation versus unfiltered controls. Filtration through a 0.05 ?m polycarbonate membrane filter did not cause distinguishable differences in the ultraviolet-visible absorption spectra of a cloud water sample previously filtered with a 0.5 ?m Teflon filter. These observations suggest that particles were neither the dominant source nor the dominant sink of the photoproduced HOOH. Freezing (up to 403 d) caused only minor changes in HOOH photoproduction rates (-9 to + 12%), and in the ultraviolet-visible absorbance spectra and pH values of the cloud water studied. These observations indicate that freeze-thaw cycles in clouds will have only minor influences on the aqueous-phase photoformation of HOOH.

Arakaki, Takemitsu; Anastasio, Cort; Shu, Pauline G.; Faust, Bruce C.

227

Entropy Budgets in Oscillating and Freezing Systems  

NASA Astrophysics Data System (ADS)

An interesting spontaneously oscillating system was demonstrated some decades ago by Welander : an open-topped water tank supplied with a continuous supply of heat is exposed to chilled air. A layer of ice forms, as one might expect. However, the ice retards the loss of heat to the air, and the water temperature rises until eventually the ice melts. The enhanced heat loss allows the system to cool again to the point where ice can form, and the cycle repeats. The oscillating behaviour is counterintuitive (like another freezing phenomenon, the Mpemba effect, wherein a warm liquid will begin freezing before a cool one), but is in full accord with the laws of thermodynamics and can be demonstrated in the laboratory and with numerical models. Oscillations occur in specific regions of parameter space (heating rate, heat transfer coefficients etc) - smooth variation, e.g. of the ice:air heat transfer coefficient yields a smooth variation of entropy production, except for a jump to increased entropy production when oscillations begin. A geophysical system where similar oscillations may occur is the icy Jovian satellite Europa, which appears to have a young crust. More generally, where a system is subject to a varying excitation (such as diurnal or seasonal forcing of the climate of Earth or Mars) the presence of phase changes such as melting of water or the condensation of carbon dioxide as frost have an important impact on the entropy budget of the system.

Lorenz, R. D.

2005-12-01

228

Fundamentals of freeze-drying.  

PubMed

Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction--the dominant mechanism of heat transfer in freeze-drying--is inefficient at the pressures used in freeze-drying. Steps should be taken to improve the thermal contact between the product and the shelf of the freeze dryer, such as eliminating metal trays from the drying process. Quantitation of the heat transfer coefficient for the geometry used is a useful way of assessing the impact of changes in the system such as elimination of product trays and changes in the vial. Because heat transfer by conduction through the vapor increases with increasing pressure, the commonly held point of view that "the lower the pressure, the better" is not true with respect to process efficiency. The optimum pressure for a given product is a function of the temperature at which freeze-drying is carried out, and lower pressures are needed at low product temperatures. The controlling resistance to mass transfer is almost always the resistance of the partially dried solids above the submination interface. This resistance can be minimized by avoiding fill volumes of more than about half the volume of the container. The development scientist should also recognize that very high concentrations of solute may not be appropriate for optimum freeze-drying, particularly if the resistance of the dried product layer increases sharply with concentration. Although the last 10 years has seen the publication of a significant body of literature of great value in allowing development scientists and engineers to "work smarter," there is still much work needed in both the science and the technology of freeze-drying. Scientific development is needed for improving analytical methodology for characterization of frozen systems and freeze-dried solids. A better understanding of the relationship between molecular mobility and reactivity is needed to allow accurate prediction of product stability at the intended storage temperature based on accelerated stability at higher temperatures. This requires that the temperature dependence of glass transition-associated mobili

Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

2002-01-01

229

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

230

Water Triple-Point Comparisons: Plateau Averaging or Peak Value?  

NASA Astrophysics Data System (ADS)

With a certain regularity, national metrology institutes conduct comparisons of water triple-point (WTP) cells. The WTP is the most important fixed point for the International Temperature Scale of 1990 (ITS-90). In such comparisons, it is common practice to simply average all the single measured temperature points obtained on a single ice mantle. This practice is quite reasonable whenever the measurements show no time dependence in the results. Ever since the first Supplementary Information for the International Temperature Scale of 1990, published by the Bureau International des Poids et Mesures in Sèvres, it was strongly suggested to wait at least 1 day before taking measurements (now up to 10 days), in order for a newly created ice mantle to stabilize. This stabilization is accompanied by a change in temperature with time. A recent improvement in the sensitivity of resistance measurement enabled the Istituto Nazionale di Ricerca Metrologica to detect more clearly the (possible) change in temperature with time of the WTP on a single ice mantle, as for old borosilicate cells. A limited investigation was performed where the temperature of two cells was monitored day-by-day, from the moment of mantle creation, where it was found that with (old) borosilicate cells it may be counterproductive to wait the usual week before starting measurements. The results are presented and discussed, and it is suggested to adapt the standard procedure for comparisons of WTP cells allowing for a different data treatment with (old) borosilicate cells, because taking the temperature dependence into account will surely reduce the reported differences between cells.

Steur, P. P. M.; Dematteis, R.

2014-04-01

231

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

232

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

233

Interspecific analysis of xylem freezing responses in Acer and Betula  

Technology Transfer Automated Retrieval System (TEKTRAN)

Temperate woody plants have evolved two methods for coping with seasonal exposure to sub-zero temperatures. Supercooling is a freeze-avoidance strategy where cells are able to resist the freezing of intracellular water below sub-zero temperatures. Non-supercooling is a freeze-tolerance strategy wh...

234

Enhancement in NGL production and improvement in water dew point temperature by optimization of slug catchers’ pressures in water dew point adjustment unit  

Microsoft Academic Search

The water dew point adjustment is one of the most important processes in all gas refineries which reduces the water content of gas to some allowable limit and separates the heavy hydrocarbons from gas. In Sarkhun gas refinery, natural gas dehydration and hydrocarbon dew point adjustment are performed by cooling method. Diethylene glycol (DEG) is injected to gas–gas heat exchanger

M. R. Rahimpour; M. Seifi; K. Paymooni; A. Shariati; S. Raeissi

2011-01-01

235

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

236

Effects of In Vitro Zinc Sulphate Additive to The Semen Extender on Water Buffalo (Bubalusbubalis) Spermatozoa before and after Freezing  

PubMed Central

Background The objective of the study was to investigate the effects of in vitro zinc sulphate additive to semen extender on sperm parameters (progressive motility, viability, membrane integrity and DNA stability) after cryopreservation. Materials and Methods In this Prospective longitudinal laboratory study, semen samples of 5 buffalo bulls of 3-5 years old were collected at 5 different occasions from Iran, Urmia during summer and autumn 2011, 25 samples were used in each treatment. Sperm progressive motility, viability and abnormal morphology were measured before and at 0.5 (T0), 1(T1) and 2(T2) hours after diluting semen(1:10 v/v) in Tris-citric acid based extender (without egg yolk and glycerol) at 37?C containing none (control group), 0.072, 0.144, 0.288, 0.576 and 1.152 mg/L zinc sulphate to investigate dose and time effects. Next, a Tris-citric acid-egg yolk-glycerol extender (20% egg yolk and 7% glycerol) containing the same amount of zinc sulphate was prepared, diluted semen (1:10 v/v) was cooled and kept into a refrigerated chamber (4?C) for 4 hours to equilibrate. Sperm progressive motility, viability, abnormal morphology, membrane integrity and DNA damage were estimated.The equilibrated semen was loaded in 0.5 ml French straws and frozen in liquid nitrogen. Later, the frozen semen was thawed and the same parameters as well as total antioxidant capacity (TAC) of the frozen-thawed semen were determined. Results The results showed that zinc sulphate additive at the rate of 0.288 mg/L gave a higher protection of sperm progressive motility (53.7 ± 1.8% vs. 40.5 ± 1.7%), viability (70.8 ± 1.8% vs. 60.1 ± 1.5%), membrane integrity (67.3 ± 1.6% vs. 56.6 ± 1.7%), DNA stability (10.1 ± 0.47% vs. 11.8 ± 0.33% damaged DNA) through the process of dilution, equilibration and freeze-thawing and caused a higher TAC level (81 ± 3.3% vs. 63 ± 3.2 µmol/L) after freez-thawing compared to the control group. Adding 0.576 and 1.152 mg/L zinc sulphate, however, was deleterious to the sperm and significantly reduced the studied sperm parameters. Conclusion Adding 0.288 mg/L zinc sulphate to the extender, compared to the control group, gives a better sperm preservation upon freezing processes which in turn, may results in higher semen fertility. But, addition of higher zinc sulphate concentrations (0.576 and 1.152 mg/L) are detrimental to buffalo spermatozoa. PMID:25379162

Dorostkar, Kamran; Alavi Shoushtari, Sayed Mortaza; Khaki, Amir

2014-01-01

237

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

238

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

239

Freezing of living cells  

SciTech Connect

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

Mazur, P.

1985-01-01

240

Three types of liquid water in icy surfaces of celestial bodies  

Microsoft Academic Search

It is shown that, at temperatures far below the triple point and under appropriate conditions, liquid water can stably or temporarily exist in upper ice-covered surfaces of planetary bodies (like Mars) in three different types:(i)undercooled interfacial water (due to freezing point depression by van der Waals forces and “premelting”),(ii)water in brines (due to freezing point depression in solutions), and(iii)sub-surface melt

D. Möhlmann

2011-01-01

241

New particle dependant parameterizations of heterogeneous freezing processes.  

NASA Astrophysics Data System (ADS)

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

Diehl, Karoline; Mitra, Subir K.

2014-05-01

242

Freezing precipitation in the Southeastern United States  

E-print Network

'un?I. . . . 2. Developmsnt. , 3. I, ocaticn of freezing prsci. pitation areas. '? ~ 4 ~ ~ ~ ? 26 ?5 25 30 32 32 33 36 38 38 39 43 44 46 47 TABLE OF CONTENTS (Continued) Page IVr ANALYSI S OF P~ERS FOR SELECTED STORMS a ~ ~ ~ ~ ~ ~ 52 Ai... farms) over a range of 850-mb temperature. s ('C) . ~ ~ ~ ~ ~ ~ ~ ~ s ~ ~ ~ ~ 63 Th number of occurrences of freezing pre ipita- tion (varicrus forms) over a range of 850-mb dcw points {'0). ~ 64 25 The number of occur ences of freezing precipita...

Young, William Robert

1978-01-01

243

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

244

Freezing temperatures of aqueous iron(III) sulfate solutions and crystallization of a new acidic water-rich sulfate  

NASA Astrophysics Data System (ADS)

An important question concerning the possibility of life under martian conditions is the existence of liquid water at low temperatures. On the martian surface, the existence of iron(III) sulfate is expected. The influence of iron(III) sulfate salt on ice deposits in respect to the formation of liquid salt brines was not investigated in the past. In this contribution, the investigation of the phase diagram of the system iron(III) sulfate-water and the influence of sulfuric acid to this system are presented. A new crystalline acidic iron(III) sulfate hydrate has been found in the ternary system iron(III) sulfate-water-sulfuric acid, which represents the most water-rich iron salt phase ever detected.

Hennings, E.; Zürner, P.; Schmidt, H.; Voigt, W.

2013-09-01

245

The effect of freezing on the sulfate-chloride and density-chloride ratios of sea-water  

E-print Network

an excess of barium chloride was added to a known volume oi' sea. - water sample which had been previously acidified, diluted, and warmed. According to Pier e and Haenisch (1948) the precipitate, barium sulphate, is thirty times more soluble in one normal... hydro- chloric acid than in pure water. In spite of this, the precipitation was carried out, in an acid medium because the precipitatis forms much larger crystals and ths carbonate and phosphate salts of barium are soluble in acid media whereas...

Burkhalter, Albert Charles

1967-01-01

246

Freezing Characteristics of Rigid Plant Tissues (Development of Cell Tension during Extracellular Freezing).  

PubMed Central

The freezing characteristics and development of cell tension during extracellular freezing were examined in supercooling stem tissues of riverbank grapes (Vitis riparia) and cold-hardened leaves of live oak (Quercus virginiana) and mountain cranberry (Vaccinium vitis-idaea). Dormant stem xylem and pith tissues of river-bank grapes were resistant to freeze-induced dehydration above the homogeneous nucleation temperature, and they developed cell tension reaching a maximum of 27 MPa. Similarly, extracellular freezing induced cell tension in the leaves of live oak and mountain cranberry. Maximum cell tension in the leaves of live oak was 16.8 MPa and 8.3 MPa in the leaves of mountain cranberry. Following peak tensions in the leaves, a decline in the pressure was observed with progressive freezing. The results suggest that resistance to cell deformation during extracellular freezing due to cell-wall rigidity can lead to reduced cell dehydration and increased cell tension. A relationship to predict freezing behavior in plant tissues based on cell rigidity is presented. Based on cell-water relations and ice nucleation rates, cell-wall rigidity has been shown to effect the freezing characteristics of plant tissues, including freeze-induced dehydration, supercooling, and homogeneous nucleation temperatures. PMID:12226313

Rajashekar, C. B.; Burke, M. J.

1996-01-01

247

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

248

HydroSense: Infrastructure-Mediated Single-Point Sensing of Whole-Home Water Activity  

E-print Network

of home water activity. Water is essential to many home activities (e.g., washing, cleaning, cooking.g., helping elders live more independently, helping people monitor their own water usage to reduce wasteHydroSense: Infrastructure-Mediated Single-Point Sensing of Whole-Home Water Activity Jon Froehlich

Anderson, Richard

249

A timescale investigation of volatile chemical retention during hydrometeor freezing: Nonrime freezing  

E-print Network

disagreement found in the studies. The theory-based analysis and methodology presented in this paper can] Collision of supercooled water with ice and subse- quent freezing to form graupel and hail is an important

Jacobson, Mark

250

Freezing, melting and structure of ice in a hydrophilic nanopore.  

PubMed

The nucleation, growth, structure and melting of ice in 3 nm diameter hydrophilic nanopores are studied through molecular dynamics simulations with the mW water model. The melting temperature of water in the pore was T(m)(pore) = 223 K, 51 K lower than the melting point of bulk water in the model and in excellent agreement with experimental determinations for 3 nm silica pores. Liquid and ice coexist in equilibrium at the melting point and down to temperatures as low as 180 K. Liquid water is located at the interface of the pore wall, increasing from one monolayer at the freezing temperature, T(f)(pore) = 195 K, to two monolayers a few degrees below T(m)(pore). Crystallization of ice in the pore occurs through homogeneous nucleation. At the freezing temperature, the critical nucleus contains approximately 75 to 100 molecules, with a radius of gyration similar to the radius of the pore. The critical nuclei contain features of both cubic and hexagonal ice, although stacking of hexagonal and cubic layers is not defined until the nuclei reach approximately 150 molecules. The structure of the confined ice is rich in stacking faults, in agreement with the interpretation of X-ray and neutron diffraction experiments. Though the presence of cubic layers is twice as prevalent as hexagonal ones, the crystals should not be considered defective Ic as sequences with more than three adjacent cubic (or hexagonal) layers are extremely rare in the confined ice. PMID:20379503

Moore, Emily B; de la Llave, Ezequiel; Welke, Kai; Scherlis, Damian A; Molinero, Valeria

2010-04-28

251

The importance of COâ on freezing point measurements of fluid inclusions: evidence from active geothermal systems and implications for epithermal ore deposition  

Microsoft Academic Search

The authors show how the melting point of ice may be calculated for a fluid of known composites. Fluid inclusion ice-melting data from New Zealand geothermal fields correlate well with values calculated using the equation presented and the measured compositions of discharges from wells from which the inclusion samples were obtained. Loss of the dominant dissolved gas, COâ during boiling

J. W. Hedenquist; R. W. Henley

1985-01-01

252

Metabolomics for in situ environmental monitoring of surface waters impacted by contaminants from both point and non-point sources  

EPA Science Inventory

We investigated the efficacy of metabolomics for field-monitoring of fish exposed to waste water treatment plant (WWTP) effluents and non-point sources of chemical contamination. Lab-reared male fathead minnows (Pimephales promelas, FHM) were held in mobile monitoring units and e...

253

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

Code of Federal Regulations, 2010 CFR

...false Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...412 Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...Albemarle Sound and the easternmost tip of Harvey Point; thence southeasterly to Day Beacon number...

2010-07-01

254

RELATIVE IMPORTANCE OF POINT SOURCE CONTAMINATION OF SURFACE WATERS: RIVER CHERWELL CATCHMENT MONITORING STUDY  

Microsoft Academic Search

A small catchment (100ha) has been characterised and instrumented at the headwater of the River Cherwell in the UK to determine the relative contribution of point and diffuse sources of surface water contamination by the cereal herbicide isoproturon. Observation of spray activities and intensive sampling of the spray vehicle used, yard washings and river water have shown that the point

WALKER A

255

A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties  

E-print Network

A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties Jeffrey R@ipst.umd.edu #12;1 Abstract A new fixed-point charge potential model for water has been developed, targeting the accurate prediction of the vapor-liquid coexistence properties over a broad temperature range. The model

256

Freeze drying apparatus  

DOEpatents

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

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

2001-01-01

257

Freeze drying method  

DOEpatents

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

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

1999-01-01

258

HACCP (Hazard Analysis and Critical Control Points) to guarantee safe water reuse and drinking water production - a case study  

Microsoft Academic Search

To obtain a sustainable water catchment in the dune area of the Flemish west coast, the integration of treated domestic wastewater in the existing potable water production process is planned. The hygienic hazards associated with the introduction of treated domestic wastewater into the water cycle are well recognised. Therefore, the concept of HACCP (Hazard Analysis and Critical Control Points) was

T. Dewettinck; E. Van Houtte; D. Geenens; K. Van Hege; W. Verstraete

2001-01-01

259

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

260

Prospective Primary School Teachers' Perceptions on Boiling and Freezing  

ERIC Educational Resources Information Center

The aim of this study was to investigate the perceptions of prospective primary school teachers on the physical state of water during the processes of boiling and freezing. There were three stages in the investigation: First, open-ended questions concerning the boiling and freezing of water were given to two groups of prospective primary school…

Senocak, Erdal

2009-01-01

261

Efflux of red cell water into buffered hypertonic solutions.  

PubMed

Buffered NaCl solutions hypertonic to rabbit serum were prepared and freezing point depressions of each determined after dilution with measured amounts of water. Freezing point depression of these dilutions was a linear function of the amount of water added. One ml. of rabbit red cells was added to each 4 ml. of the hypertonic solutions and after incubation at 38 degrees C. for 30 minutes the mixture was centrifuged and a freezing point depression determined on the supernatant fluid. The amount of water added to the hypertonic solutions by the red cells was calcuated from this freezing point depression. For each decrease in the freezing point of -0.093 degrees C. of the surrounding solution red cells gave up approximately 5 ml. of water per 100 ml. of red cells in the range of -0.560 to -0.930 degrees C. Beyond -0.930 degrees C. the amount of water given up by 100 ml. of red cells fits best a parabolic equation. The maximum of this equation occurred at a freezing point of the hypertonic solution of -2.001 degrees C. at which time the maximum amount of water leaving the red cells would be 39.9 ml. per 100 ml. of red cells. The data suggest that only about 43 per cent of the red cell water is available for exchange into solutions of increasing tonicity. PMID:14428774

OLMSTEAD, E G

1960-03-01

262

A Pollution Offset System for Trading NonPoint Source Water Pollution Permits  

Microsoft Academic Search

Water pollution from non-point sources is a global environmental concern. Economists propose tradable permit systems as a\\u000a solution, but they are difficult to implement due to the nature of non-point sources. We present a pollution offset system\\u000a for trading non-point source water pollution permits. Conventional pollution offset systems suffer from thin markets and transaction\\u000a costs. In this paper, we show

R. A. Ranga Prabodanie; John F. Raffensperger; Mark W. Milke

2010-01-01

263

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

264

Exploring the Nature of Contact Freezing  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

265

Freezing tolerance of conifer seeds and germinants.  

PubMed

Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation between seedlot hardiness and rate of germination. Germination rate and freezing tolerance of Douglas-fir and western red cedar seedlots was negatively correlated. There was a significant correlation between LT50 after 10 days in the growth chamber and minimum spring temperature at the location of seedlot origin for interior spruce and three seedlots of western red cedar, but no relationship was apparent for lodgepole pine and Douglas-fir. PMID:14652223

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

2003-12-01

266

Freezing of living cells: mechanisms and implications.  

PubMed

Cells can endure storage at low temperatures such as--196 degrees 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. PMID:6383068

Mazur, P

1984-09-01

267

Inhibition of heavy metal ion corrosion on aluminum in fresh water cooling systems using propylene glycol anti-freeze  

SciTech Connect

Electronics cooling and environmental control systems are required in enclosed manned spaces such as the inside of spacecraft or submersibles. Because egress from such spaces may not be possible in a short time frame, coolant leaks must have minimum toxicity. For this reason, propylene glycol coolants are preferred over the traditional ethylene glycol coolants. Corrosion inhibitor formulations are well developed for ethylene glycol coolants, but there is concern that the inhibitor suite for propylene glycol systems may not be as mature. In particular, coolant systems with a mixture of aluminum and copper can develop heavy metal ion corrosion of the aluminum due to precipitation of copper ions from solution onto the aluminum. This type of accelerated corrosion of aluminum does not require electrical contact with copper, as is the case for galvanic corrosion, nor is significant coolant conductivity required for corrosion to occur. This paper presents a study of the ability of a commercial inhibited propylene glycol coolant to prevent heavy metal ion corrosion of aluminum when copper is also present in the coolant system. The inhibited propylene glycol`s performance is compared to that of reagent propylene glycol without inhibitors, a mature ethylene glycol inhibited coolant, and to tap water. The inhibitor suite in the inhibited propylene glycol was found to be as effective in controlling heavy metal ion corrosion as that of the inhibited ethylene glycol coolant, while uninhibited reagent propylene glycol was ineffective in controlling heavy metal ion corrosion.

Hack, H.P. [Northrop Grumman Corp., Annapolis, MD (United States). Electronic Sensors and Systems Div.; Corbett, R.; Krantz, B. [Corrosion Testing Labs., Newark, DE (United States)

1998-12-31

268

RADON REMOVAL USING POINT-OF-ENTRY WATER TREATMENT TECHNIQUES  

EPA Science Inventory

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

269

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...

270

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

271

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

2011-08-01

272

Theory of freezing in simple systems  

SciTech Connect

The transition parameters for the freezing of two one-component liquids into crystalline solids are evaluated by two theoretical approaches. The first system considered is liquid sodium which crystallizes into a body-centered-cubic (bcc) lattice; the second system is the freezing of adhesive hard spheres into a face-centered-cubic (fcc) lattice. Two related theoretical techniques are used in this evaluation: One is based upon a recently developed bifurcation analysis; the other is based upon the theory of freezing developed by Ramakrishnan and Yussouff. For liquid sodium, where experimental information is available, the predictions of the two theories agree well with experiment and each other. The adhesive-hard-sphere system, which displays a triple point and can be used to fit some liquids accurately, shows a temperature dependence of the freezing parameters which is similar to Lennard-Jones systems. At very low temperature, the fractional density change on freezing shows a dramatic increase as a function of temperature indicating the importance of all the contributions due to the triplet direction correlation function. Also, we consider the freezing of a one-component liquid into a simple-cubic (sc) lattice by bifurcation analysis and show that this transition is highly unfavorable, independent of interatomic potential choice. The bifurcation diagrams for the three lattices considered are compared and found to be strikingly different. Finally, a new stability analysis of the bifurcation diagrams is presented.

Cerjan, C.; Bagchi, B.

1985-03-01

273

The effect on oil recovery of water flooding at pressures above and below the bubble point  

E-print Network

THE EFFECT ON OIL RECOYERY OF WATER F LOODING AT PRESSURES ABOVE AND BELOW THE BUBBLE POINT DANIEL M. BASS JR. LIBRARY A & B COLLEGE OF 7EXAS TIEE EFFECT ON OIL RECOVERY OF WATER F LOODINQ AT PRESSURES ABOVE AND BELOW THE BUBBLE POINT A... EFFECT ON OIL RECOVERY OF WATER F LOODINQ AT PRESSURES ABOVE AND BELOW TIIE BUBBLE POINT A Thesis By DANIEL M. BASS JR. Approved as to style and content by: J Chairman of Committee ead of Department TABLE OF CONTENTS I ABSTRACT. Z. INTRODUCTION...

Bass, Daniel Materson

1955-01-01

274

Improved freezing level retrieval  

E-print Network

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

Hong, Sungwook

2002-01-01

275

Building the water edge : a public event for art and artists at Fort Point Channel  

E-print Network

The thesis deals with building the water edge at Fort Point Channel, between Congress Street and Summer Street Bridges. It serves as a public event that intends to establish continuity of movement along the waterfront. The ...

Godwin, Audrey

1996-01-01

276

IMPROVEMENT OF STORM-WATER RESERVOIRS FOR REDUCTION OF NON-POINT POLLUTION FROM URBAN AREA  

NASA Astrophysics Data System (ADS)

As a new measure for reduction of non-point pollution, we apply storm-water reservoirs in which basket mats are wholly and partially installed to improve flow patterns and increase residence time of particulate matter of non-point sources. To clarify the reduction effect of non-point sources using the improved storm-water reservoirs, we conducted field measurements on the bottom sediments in reservoirs located within the watershed of Lake Inba-numa. The measured results reveal that the improvement of the storm-water reservoirs may increase appreciably the trap effect of non-point pollution especially in the basket mats located near the inlet. These facts indicate that the partial improvements neat the inlets may be effective for the reduction of non-point sources in the whole watershed of Lake Inba-numa.

Sato, Kazuhiro; Nihei, Yasuo; Sakai, Jyun; Shigematsu, Manami; Ono, Fumio; Yuasa, Takashi; Uehara, Hiroshi; Syouji, Tarou; Ogura, Hisako

277

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

278

A Chemical Test of Critical Point Isomorphism: Reactive Dissolution of Ionic Solids in Isobutyric Acid + Water near the Consolute Point.  

PubMed

Binary liquid mixtures having a consolute point can be used as solvents for chemical reactions. When excess cerium(IV) oxide is brought into equilibrium with a mixture of isobutyric acid + water, and the concentration of cerium in the liquid phase is plotted in van't Hoff form, a straight line results for temperatures sufficiently in excess of the critical solution temperature. Within 1 K of the critical temperature, however, the concentration becomes substantially suppressed, and the van't Hoff slope diverges toward negative infinity. According to the phase rule, one mole fraction can be fixed. Given this restriction, the temperature behavior of the data is in exact agreement with the predictions of both the principle of critical point isomorphism and the Gibbs-Helmholtz equation. In addition, we have determined the concentration of lead in the liquid phase when crystalline lead(II) sulfate reacts with potassium iodide in isobutyric acid + water. When plotted in van't Hoff form, the data lie on a straight line for all temperatures including the critical region. The phase rule indicates that two mole fractions can be fixed. With this restriction, the data are in exact agreement with the principle of critical point isomorphism. PMID:25668071

Baird, James K; Baker, Jonathan D; Hu, Baichuan; Lang, Joshua R; Joyce, Karen E; Sides, Alison K; Richey, Randi D

2015-03-12

279

AN APPROACH TO WATER RESOURCES EVALUATION OF NON-POINT SILVICULTURAL SOURCES (A PROCEDURAL HANDBOOK)  

EPA Science Inventory

This handbook provides an analysis methodology that can be used to describe and evaluate changes to the water resource resulting from non-point silvicultural activities. This state-of-the-art approach for analysis and prediction of pollution from non point silvicultural activitie...

280

Water-cooled end-point boundary temperature control of hot strip via dynamic programming  

Microsoft Academic Search

In this paper, an end-point boundary temperature control approach for runout table cooling used in hot strip mills is presented. The system relies on a linearized model for describing heat radiated to the environment and heat transferred to cooling water. At first, a conventional feedforward control design to control the temperature at the end-point boundary, the only measurable controlled parameter,

Nicholas S. Samaras; Marwan A. Simaan

1998-01-01

281

Water cooled end-point boundary temperature control of hot strip via dynamic programming  

Microsoft Academic Search

This paper presents a system for end-point boundary temperature control approach, for run out table (ROT) cooling, used in hot strip mills. The system relies on a linearized model for describing heat radiated to the environment and heat transferred to cooling water. A conventional feedforward control design to control the temperature at the end boundary point, the only measurable controlled

Nicholas S. Samaras; M. A. Simaan

1997-01-01

282

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...

283

Freeze-drying of lactic acid bacteria.  

PubMed

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

Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

2015-01-01

284

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

285

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

286

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 an 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 allowing to determine the temperature dependent ice nucleation probability of size selected aerosol particles. The method uses supercooled charged water droplets suspended 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 time scale of our experiment.

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

2013-04-01

287

Herd contact structure based on shared use of water points and grazing points in the Highlands of Ethiopia.  

PubMed

The use of shared common water points (WPs) and grazing points (GPs) at two different levels of administrative aggregation (village and kebelle) in a region of the Highlands of Ethiopia was explored by means of a questionnaire survey and social network analysis. Despite GPs being more abundant than WPs (208 and 154, respectively), individual GPs provide more contact opportunities for animals. There was great variability in the contact structure of the selected villages within kebelles for both networks, with this variability being higher in the GP networks for each kebelle. Contrary to the commonly held view that WPs are critical for the potential transmission of infectious diseases, intervention at GPs in the Ethiopian Highlands may have greater impact on contacts and thereby opportunities for transmission of infectious diseases between flocks. Some villages appear naturally at much lower risk of introducing disease. These findings could help the design of surveillance and control activities for directly transmitted infectious diseases. PMID:20642874

Waret-Szkuta, A; Ortiz-Pelaez, A; Pfeiffer, D U; Roger, F; Guitian, F J

2011-06-01

288

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

289

Physiological responses to freezing in hatchlings of freeze-tolerant and -intolerant turtles.  

PubMed

Freeze tolerance is a complex cold-hardiness adaptation that has independently evolved in a diverse group of organisms, including several ectothermic vertebrates. Because little is known about the mechanistic basis for freeze tolerance in reptiles, we compared responses to experimental freezing in winter-acclimatized hatchlings representing nine taxa of temperate North American turtles, including ones that tolerated freezing and others that did not. Viability rates of hatchlings frozen to -3 degrees C for 72 h ranged from 0 to 100%. Tolerance to freezing was poor in Sternotherus odoratus, Graptemys geographica and Trachemys scripta, intermediate in Chelydra serpentina, and high in Emydoidea blandingii, Chrysemys picta bellii, C. p. marginata, Malaclemys terrapin, and Terrapene ornata, and generally reflected the winter thermal ecology of each taxon. Plasma activity of lactate dehydrogenase (LDH), a novel in vivo index of freeze/thaw damage, corroborated viability assessments and demonstrated that cryoinjury occurred even in surviving turtles. Irrespective of taxon, cryoinjury tended to be higher in smaller individuals and in those having relatively low water contents; however, bases for these associations were not apparent. Screening for certain organic osmolytes that might promote freezing survival by colligatively reducing ice content and limiting cell dehydration showed that the plasma of unfrozen (control) turtles contained small quantities of glucose (1.3-5.8 mmol l(-1)) and lactate (0.6-3.2 mmol l(-1)) and modest amounts of urea (range of mean values for all taxa 8.2-52.3 mmol l(-1)). Frozen/thawed turtles of all taxa accumulated modest amounts of glucose and lactate that jointly raised the plasma solute concentration by 30-100 mmol l(-1). We conclude that organic osmolytes accumulated both before and during freezing may promote survival in species that have evolved a tolerance to freezing, but are not necessarily accumulated for that purpose. PMID:16758216

Costanzo, Jon P; Baker, Patrick J; Lee, Richard E

2006-09-01

290

Percolation with Constant Freezing  

NASA Astrophysics Data System (ADS)

We introduce and study a model of percolation with constant freezing ( PCF) where edges open at constant rate , and clusters freeze at rate independently of their size. Our main result is that the infinite volume process can be constructed on any amenable vertex transitive graph. This is in sharp contrast to models of percolation with freezing previously introduced, where the limit is known not to exist. Our interest is in the study of the percolative properties of the final configuration as a function of . We also obtain more precise results in the case of trees. Surprisingly the algebraic exponent for the cluster size depends on the degree, suggesting that there is no lower critical dimension for the model. Moreover, even for , it is shown that finite clusters have algebraic tail decay, which is a signature of self organised criticality. Partial results are obtained on , and many open questions are discussed.

Mottram, Edward

2014-06-01

291

Potential food applications of high-pressure effects on ice-water transitions  

Microsoft Academic Search

Pressure depresses the freezing point of water and the melting point of ice, as well as enabling various high-density forms of ice to be obtained. These effects of pressure on the solid-liquid phase diagram of water have several potential applications in food technology, including pressure-assisted freezing, pressure-assisted thawing and non-frozen storage at low temperature (under pressure). Studies that have been

M. T. Kalichevsky; D. Knorr; P. J. Lillford

1995-01-01

292

Freezing of Lennard-Jones-type fluids  

SciTech Connect

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

Khrapak, Sergey A. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany); Joint Institute for High Temperatures, 125412 Moscow (Russian Federation); Chaudhuri, Manis; Morfill, Gregor E. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany)

2011-02-07

293

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

Code of Federal Regulations, 2011 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...

2011-07-01

294

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

Code of Federal Regulations, 2010 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...

2010-07-01

295

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

Code of Federal Regulations, 2014 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...

2014-07-01

296

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

Code of Federal Regulations, 2012 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...

2012-07-01

297

Dynamical Interpretation of Chemical Freeze-Out Parameters  

E-print Network

It is shown that the condition for chemical freeze-out, average energy per hadron approximately 1 GeV, selects the softest point of the equation of state, namely the point where the pressure divided by the energy density has a minimum. The sensitivity to the equation of state used is discussed. The previously proposed mixed phase model, which is consistent with lattice QCD data naturally leads to the chemical freeze-out condition.

V. D. Toneev; J. Cleymans; E. G. Nikonov; K. Redlich; A. A. Shanenko

1999-04-17

298

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

SciTech Connect

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

Koop, T.; Luo, B.; Biermann, U.M.; Crutzen, P.J.; Peter, T. [Max Planck Inst. for Chemistry, Mainz (Germany)] [Max Planck Inst. for Chemistry, Mainz (Germany)

1997-02-06

299

On the Paradox of Chilling Water: Crossover Temperature in the Mpemba Effect  

Microsoft Academic Search

Unlike most of the research on the Mpemba effect which has focused on verifying the observation that warm water freezes faster than cold water, our work quantitatively investigates the rates at which hot and cold water cool and the point at which hot water reaches a lower temperature than cold water under a set of external conditions. Using a vacuum

Andrew Wang; Monica Chen; Yanni Vourgourakis; Antonio Nassar

2011-01-01

300

Freezing Poultry for Home Use  

E-print Network

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

Davis, Michael

2006-08-31

301

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.

2012-06-26

302

Freeze Branding Horses  

E-print Network

, simpli- f_ied drawing of one hair shaft with its color (pigment) producing follicle (CF) and its growth follicle (GF), both shown below the skin. Doug Householder 1 , Gary Webb 2 , Sam Wigington 3 and Jason Bruemmer 4 Freeze Branding Horses Figure 1. Hair...

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

2001-06-29

303

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...

304

Impact of point and nonpoint source pollution on pore waters of two Chesapeake Bay tributaries.  

PubMed

Chesapeake Bay and its tributaries are contaminated by industrial and municipal point sources and agricultural nonpoint sources of pollution. The objective of this study was to compare the porewater characteristics of two Chesapeake Bay tributaries: Wicomico River (WR) contaminated by point source and Pocomoke River (PR) contaminated by both point and nonpoint sources of pollution. Four study sites (1 mile before, adjacent to, and 1 and 2 miles after the sewage treatment plant) were chosen to collect sediment samples in both the rivers. The sediment-pore waters were analyzed for toxicity using Microtox marine luminescent bacteria-Vibrio fischeri. USEPA toxicity identification evaluation tests on these pore waters confirmed that the contaminants (ammonia and heavy metals) in WR were from municipal point sources, whereas in PR the contamination (metals, pesticides, and PCBs) was from nonpoint sources (agriculture) of pollution. The toxicity (and the concentration of contaminants) decreased both upstream and downstream from the most polluted site in both the rivers. PMID:8930508

Karuppiah, M; Gupta, G

1996-10-01

305

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

E-print Network

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 point. If the liquid-liquid critical point hypothesis is true there must be a maximum in the specific heat at some temperature $T>T_{H}$ for any pressure $P>P_{c}$ (being $T_{H}$ the homogeneous nucleation temperature and $P_{c}$ the pressure of the second critical point). This maximum does not appear for the singularity free scenario.

Manuel I. Marques

2007-01-23

306

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2011 CFR

...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

2011-01-01

307

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2013 CFR

...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

2013-01-01

308

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2012 CFR

...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

2012-01-01

309

7 CFR 58.621 - Freezing tunnels.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

310

7 CFR 58.621 - Freezing tunnels.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

311

7 CFR 58.621 - Freezing tunnels.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

312

7 CFR 58.621 - Freezing tunnels.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

313

7 CFR 58.621 - Freezing tunnels.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

314

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2014 CFR

...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

2014-01-01

315

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2010 CFR

...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

2010-01-01

316

Biotechnological applications of plant freezing associated Ghislain Breton1  

E-print Network

freezing in deep water or soil while those that live at the surface adopt different mechanisms. Some try been used to produce transgenic plants. These studies have revealed the potential capacity of different

Sarhan, Fathey

317

Glass transition in biomolecules and the liquid-liquid critical point of water  

E-print Network

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 $C_P$ 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.

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

2006-08-28

318

Single-Point Magnetic Resonance Imaging Study of Water Adsorption in Pellets of Zeolite 4A  

Microsoft Academic Search

The water uptake process in commercial type particles of zeolite 4A has been studied using a single-point MRI method. True proton density,T1,T2, andT*2relaxation times were obtained with submillimetric resolution, overcoming the restrictions of shortT*2signals. The molecular mobility in nonequilibrium conditions has been characterized by relaxation time mapping. A clear reduction of the water sorption rate was observed by comparing MRI

Pablo J. Prado; Bruce J. Balcom; Mohamed Jama

1999-01-01

319

Partial molar volumes and activity coefficients of the water in aqueous polyol solutions and the osmotic pressures of these solutions  

Microsoft Academic Search

The freezing-point depression and density of aqueous polyol (alditol) solutions were measured, and the osmotic pressure and\\u000a the partial molar volume of the water of these solutions were calculated. The osmotic pressures calculated from the freezing-point\\u000a depression data were compared with those calculated with van't Hoff's equation and fairly good agreement was found. The partial\\u000a molar volumes of the water

Keitaro Kiyosawa

1992-01-01

320

Water loss at normal enamel histological points during air drying at room temperature.  

PubMed

This in vitro study aimed to quantify water loss at histological points in ground sections of normal enamel during air drying at room temperature (25°C) and relative humidity of 50%. From each of 10 ground sections of erupted permanent human normal enamel, three histological points (n = 30) located at 100, 300 and 500 ?m from enamel surface and along a transversal following prisms paths were characterized regarding the mineral, organic and water volumes. Water loss during air drying was from 0 to 48 h. Drying occurred with both falling and constant-drying rates, and drying stabilization times (Teq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples (n = 5; 15 points), Teq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10?? cm² s?¹. Our data provide evidence of air drying resulting in air replacing enamel's loosely bound water in prisms sheaths following a unidirectional water diffusion rate of 3.47 × 10?? cm² s?¹ (from the original enamel surface inward), not necessarily resulting in water evaporating directly into air, with important implications for transport processes and optical and mechanical properties. PMID:23557383

De Medeiros, R C G; De Lima, T A S; Gouveia, C R; De Sousa, F B

2013-06-01

321

Existence of a mannitol hydrate during freeze-drying and practical implications.  

PubMed

We report thermal and crystallographic evidence for a previously unknown mannitol hydrate that is formed in the process of freeze-drying. The mannitol hydrate was produced by freeze-drying pure mannitol solutions (1-4% w/v) using the following cycle: (1) equilibration at -5 degreesC for 1 h; (2) freezing at -40 degreesC; (3) primary drying at -10 degreesC for 15 h; and (4) secondary drying at 10 degreesC for 2 h and then 25 degreesC for 5 h. This crystal form was also observed upon freeze-drying in the presence of sorbitol (1% w/v). The mannitol hydrate showed a distinct X-ray powder diffraction pattern, low melting point, and steplike desolvation behavior that is characteristic of crystalline hydrates. The mannitol hydrate was found to be metastable, converting to anhydrous polymorphs of mannitol upon heating and exposure to moisture. The amount of the mannitol hydrate varied significantly from vial to vial, even within the same batch. The formation of mannitol hydrate has several potential consequences: (1) reduced drying rate; (2) redistribution of the residual hydrate water during accelerated storage to the amorphous drug; and (3) vial-to-vial variation of the moisture level. PMID:9950638

Yu, L; Milton, N; Groleau, E G; Mishra, D S; Vansickle, R E

1999-02-01

322

Freezing and anoxia tolerance of slugs: a metabolic perspective.  

PubMed

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 circumscriptus. The introduced species showed very poor freezing survival. Supercooling points of the introduced species were quite high ( approximately -3 degrees C) and their freezing survival was very poor, limited to short-term freezing at -1.2 to -1.5 degrees C and low ice contents (23-44%). D. laeve showed a significant elevation of supercooling point between slugs collected in the autumn (-4.8 degrees C +/- 0.5) and those collected early in the spring (-3.1 degrees C +/- 0.4). This species also showed substantial freezing survival which was greater for spring-collected slugs (100% survival of 1 h freezing at -2 degrees C with an ice content of 65%) than for autumn animals (100% survival for 1 h at -1 degrees C with approximately 40% ice). Carbohydrate and amino acid responses to freezing and anoxia exposures were compared in the two Deroceras species. D. laeve showed a strong hyperglycemic response to freezing, a 100-fold increase in glucose levels that suggested that glucose may have a cryoprotective function in this species. D. reticulatum did not accumulate glucose and neither species produced glycerol or lactate. Both species showed typical responses to anoxia (aspartate and glutamate catabolism, alanine and succinate accumulation) and D. laeve also showed this pattern during freezing, suggesting a natural switch to anaerobiosis to support freezing survival. PMID:17628806

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

2007-11-01

323

Experimental evidence of the ferroelectric phase transition near the $\\lambda-$point in liquid water  

E-print Network

We studied dielectric properties of nano-sized liquid water samples confined in polymerized silicates MCM-41 characterized by the porous sizes \\sim 3-10nm. We report the direct measurements of the dielectric constant by the dielectric spectroscopy method at frequencies 25Hz-1MHz and demonstrate clear signatures of the second-order phase transition of ferroelectric nature at temperatures next to the \\lambda- point in the bulk supercooled water. The presented results support the previously developed polar liquid phenomenology and hence establish its applicability to model actual phenomena in liquid water.

Fedichev, P O; Bordonskiy, G S; Orlov, A O

2011-01-01

324

A new approach for freezing of aqueous solutions under active control of the nucleation temperature.  

PubMed

An experimental setup for controlled freezing of aqueous solutions is introduced. The special feature is a mechanism to actively control the nucleation temperature via electrofreezing: an ice nucleus generated at a platinum electrode by the application of an electric high voltage pulse initiates the crystallization of the sample. Using electrofreezing, the nucleation temperature in pure water can be precisely adjusted to a desired value over the whole temperature range between a maximum temperature Tn(max) close to the melting point and the temperature of spontaneous nucleation. However, the presence of additives can inhibit the nucleus formation. The influence of hydroxyethylstarch (HES), glucose, glycerol, additives commonly used in cryobiology, and NaCl on Tn(max) were investigated. While the decrease showed to be moderate for the non-ionic additives, the hindrance of nucleation by ionic NaCl makes the direct application of electrofreezing in solutions with physiological salt concentrations impossible. Therefore, in the multi-sample freezing device presented in this paper, the ice nucleus is produced in a separate volume of pure water inside an electrode cap. This way, the nucleus formation becomes independent of the sample composition. Using electrofreezing rather than conventional seeding methods allows automated freezing of many samples under equal conditions. Experiments performed with model solutions show the reliability and repeatability of this method to start crystallization in the test samples at different specified temperatures. The setup was designed to freeze samples of small volume for basic investigations in the field of cryopreservation and freeze-drying, but the mode of operation might be interesting for many other applications where a controlled nucleation of aqueous solutions is of importance. PMID:16887112

Petersen, Ansgar; Schneider, Hendrik; Rau, Guenter; Glasmacher, Birgit

2006-10-01

325

Pay Attention to Rural NonPoint Source Pollution, Guarantee the Security of Drinking Water  

Microsoft Academic Search

With the rapid development of agricultural modernization in China great changes have taken place in the rural economy visage. But subsequently various pollution problems emerge out more frequently and especially because of the aggravating non-point source pollution the safety of drinking water in the vast rural areas has suffered a lot from severe threats which is drawing more and more

Jingdong Zhang; Yuan Zhou; Jiawen Wang

2009-01-01

326

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...

327

Plant responses, climate pivot points, and trade-offs in water-limited ecosystems  

USGS Publications Warehouse

Plant species in dryland ecosystems are limited by water availability and may be vulnerable to increases in aridity. Methods are needed to monitor and assess the rate of change in plant abundance and composition in relation to climate, understand the potential for degradation in dryland ecosystems, and forecast future changes in plant species assemblages. I employ nearly a century of vegetation monitoring data from three North American deserts to demonstrate an approach to determine plant species responses to climate and critical points over a range of climatic conditions at which plant species shift from increases to decreases in abundance (climate pivot points). I assess these metrics from a site to regional scale and highlight how these indicators of plant performance can be modified by the physical and biotic environment. For example, shrubs were more responsive to drought and high temperatures on shallow soils with limited capacity to store water and fine-textured soils with slow percolation rates, whereas perennial grasses were more responsive to precipitation in sparse shrublands than in relatively dense grasslands and shrublands, where competition for water is likely more intense. The responses and associated climate pivot points of plant species aligned with their lifespan and structural characteristics, and the relationship between responses and climate pivot points provides evidence of the trade-off between the capacity of a plant species to increase in abundance when water is available and its drought resistance.

Munson, Seth M.

2013-01-01

328

A point focusing collector for an integrated water/power complex  

NASA Technical Reports Server (NTRS)

The utilization potential of the point focusing parabolic dish is identified. Its main design parameters are summarized. Performance tests and the utilization of the collector as primary energy source in a food-water-power complex are described. Process heat, heat storage, heat transfer, and cogeneration are discussed.

Zewen, H.; Schmidt, G.; Moustafa, S.

1982-01-01

329

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

330

Langevin Poisson-Boltzmann equation: point-like ions and water dipoles near a charged surface.  

PubMed

Water ordering near a charged membrane surface is important for many biological processes such as binding of ligands to a membrane or transport of ions across it. In this work, the mean-field Poisson-Boltzmann theory for point-like ions, describing an electrolyte solution in contact with a planar charged surface, is modified by including the orientational ordering of water. Water molecules are considered as Langevin dipoles, while the number density of water is assumed to be constant everywhere in the electrolyte solution. It is shown that the dielectric permittivity of an electrolyte close to a charged surface is decreased due to the increased orientational ordering of water dipoles. The dielectric permittivity close to the charged surface is additionally decreased due to the finite size of ions and dipoles. PMID:21613667

Gongadze, Ekaterina; van Rienen, Ursula; Kralj-Igli?, Veronika; Igli?, Aleš

2011-06-01

331

Second critical point of water in supercooled confined water in L,L-diphenylalanine micro/nanotubes  

E-print Network

The temperature dependence (10-290 K) of the low-frequency (20-150 cm-1) Raman-active phonon modes of supercooled con?ned water in L,L-diphenylalanine micro/nanotubes was analysed. The isolated dynamics of a specific geometry of water cluster (pentamer) in supercooled confined regime was studied in detail. A particular mode concerning water-nanotube interaction was also probed. A fragile-to-strong transition at 204 K was observed and related to the crossing of the Widom line. The critical exponent analyses of the relaxation rate data based on mode-coupling theory indicated perfect agreement among experimental data and theory. Our results are consistent with the existence of a second critical point of water.

P. M. G. L. Ferreira; S. Kogikoski Jr.; W. A. Alves; H. Martinho

2014-06-26

332

Evaluation and Validation of the Messinger Freezing Fraction  

NASA Technical Reports Server (NTRS)

One of the most important non-dimensional parameters used in ice-accretion modeling and scaling studies is the freezing fraction defined by the heat-balance analysis of Messinger. For fifty years this parameter has been used to indicate how rapidly freezing takes place when super-cooled water strikes a solid body. The value ranges from 0 (no freezing) to 1 (water freezes immediately on impact), and the magnitude has been shown to play a major role in determining the physical appearance of the accreted ice. Because of its importance to ice shape, this parameter and the physics underlying the expressions used to calculate it have been questioned from time to time. Until now, there has been no strong evidence either validating or casting doubt on the current expressions. This paper presents experimental measurements of the leading-edge thickness of a number of ice shapes for a variety of test conditions with nominal freezing fractions from 0.3 to 1.0. From these thickness measurements, experimental freezing fractions were calculated and compared with values found from the Messinger analysis as applied by Ruff. Within the experimental uncertainty of measuring the leading-edge thickness, agreement of the experimental and analytical freezing fraction was very good. It is also shown that values of analytical freezing fraction were entirely consistent with observed ice shapes at and near rime conditions: At an analytical freezing fraction of unity, experimental ice shapes displayed the classic rime shape, while for conditions producing analytical freezing fractions slightly lower than unity, glaze features started to appear.

Anderson, David N.; Tsao, Jen-Ching

2005-01-01

333

Damage Evaluation on Freeze-Thawing Process of Food by Using NMR  

NASA Astrophysics Data System (ADS)

Freeze-thawing process gives significant damages for food structure. Several new techniques have been attempted for quantitative evaluation of the damages. In this study, using NMR (nuclear magnetic resonance) with a stimulated echo method, restricted diffusion phenomena of water molecules was measured for damaged food (onion and tuna) tissues that were subjected to the repeat of freeze-thawing, Through experiments, water permeability of tissue membrane was calculated. The water permeability of fresh tissues for onion showed clearly restricted diffusion, but after freeze-thawing, it disappeared. On the other hand, the water permeability of fresh tuna tissue was small significantly, even though it was a little higher after freeze-thawing. After all, the damage level after freeze-thawing showed a significant difference between onion and tuna. These results support the view that plant tissue is very sensitive to freeze-thawing and that the water permeability of plant is much lower than that of animal.

Andou, Hiroko; Fukuoka, Mika; Miyawaki, Osato; Suzuki, Toru

334

Bacterial treatment effectiveness of point-of-use ceramic water filters.  

PubMed

Laboratory experiments were conducted on six point-of-use (POU) ceramic water filters that were manufactured in Nicaragua; two filters were used by families for ca. 4 years and the other filters had limited prior use in our lab. Water spiked with ca. 10(6)CFU/mL of Escherichia coli was dosed to the filters. Initial disinfection efficiencies ranged from 3 - 4.5 log, but the treatment efficiency decreased with subsequent batches of spiked water. Silver concentrations in the effluent water ranged from 0.04 - 1.75 ppb. Subsequent experiments that utilized feed water without a bacterial spike yielded 10(3)-10(5)CFU/mL bacteria in the effluent. Immediately after recoating four of the filters with a colloidal silver solution, the effluent silver concentrations increased to 36 - 45 ppb and bacterial disinfection efficiencies were 3.8-4.5 log. The treatment effectiveness decreased to 0.2 - 2.5 log after loading multiple batches of highly contaminated water. In subsequent loading of clean water, the effluent water contained <20-41 CFU/mL in two of the filters. This indicates that the silver had some benefit to reducing bacterial contamination by the filter. In general these POU filters were found to be effective, but showed loss of effectiveness with time and indicated a release of microbes into subsequent volumes of water passed through the system. PMID:19500815

Bielefeldt, Angela R; Kowalski, Kate; Summers, R Scott

2009-08-01

335

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

Code of Federal Regulations, 2011 CFR

...Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted area. (a) The area. Beginning on the north shore of Albemarle Sound and the easternmost tip of Harvey Point; thence southeasterly to Day Beacon number 3; thence southeasterly to...

2011-07-01

336

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

Code of Federal Regulations, 2012 CFR

...Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted area. (a) The area. Beginning on the north shore of Albemarle Sound and the easternmost tip of Harvey Point; thence southeasterly to Day Beacon number 3; thence southeasterly to...

2012-07-01

337

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

Code of Federal Regulations, 2013 CFR

...Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted area. (a) The area. Beginning on the north shore of Albemarle Sound and the easternmost tip of Harvey Point; thence southeasterly to Day Beacon number 3; thence southeasterly to...

2013-07-01

338

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

Code of Federal Regulations, 2014 CFR

...Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted area. (a) The area. Beginning on the north shore of Albemarle Sound and the easternmost tip of Harvey Point; thence southeasterly to Day Beacon number 3; thence southeasterly to...

2014-07-01

339

Did Water Leave Its Mark on Mars?  

ERIC Educational Resources Information Center

Discusses the missing water on Mars. Describes five experiments simulating conditions on Mars: (1) behavior of dry ice; (2) low-pressure vacuum; (3) freezing point depression; (4) water in hydrated minerals and clay; and (5) properties of carbon dioxide. (YP)

Secosky, James J.

1989-01-01

340

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...

341

Effects of Electric and Magnetic Field on Freezing and Possible Relevance in Freeze Drying  

Microsoft Academic Search

Application of an electric or magnetic field can significantly affect the freezing characteristics of water. A DC electric field will tend to induce ice nucleation at a lower degree of supercooling, and there is evidence to show that an AC electric field delays the onset of ice nucleation. Industrial research has shown that a magnetic field can be used to

M. W. Woo; A. S. Mujumdar

2010-01-01

342

Slow dehydration promotes desiccation and freeze tolerance in the Antarctic midge Belgica antarctica.  

PubMed

Adaptations to low moisture availability are arguably as important as cold resistance for polar terrestrial invertebrates, especially because water, in the form of ice, is biologically inaccessible for much of the year. Desiccation responses under ecologically realistic soil humidity conditions--those close to the wilting points of plants [98.9% relative humidity (RH)]--have not previously been examined in polar insect species. In the current study we show that, when desiccated at 98.2% RH, larvae of the Antarctic midge Belgica antarctica are more tolerant of dehydration than larvae desiccated at lower humidities (75% RH), and develop an increased tolerance to freezing. The slow rate of desiccation at this high RH enabled more than 50% of larvae to survive the loss of >75% of their osmotically active water (OAW). Survival rates were further increased when rehydration was performed at 100% RH, rather than by direct contact with water. Two days at 98.2% RH resulted in a approximately 30% loss of OAW, and dramatically increased the freeze tolerance of larvae to -10 and -15 degrees C. The supercooling point of animals was not significantly altered by this desiccation treatment, and all larvae were frozen at -10 degrees C. This is the first evidence of desiccation increasing the freeze tolerance of a polar terrestrial arthropod. Maximum water loss and body fluid osmolality were recorded after 5 days at 98.2% RH, but osmolality values returned to predesiccated levels following just 1 h of rehydration in water, well before all the water lost through desiccation had been replenished. This suggests active removal of osmolytes from the extracellular fluids during the desiccation process, presumably to intracellular compartments. Heat-shock proteins appear not to contribute to the desiccation tolerance we observed in B. antarctica. Instead, we suggest that metabolite synthesis and membrane phospholipid adaptation are likely to be the underpinning physiological mechanisms enhancing desiccation and cold tolerance in this species. PMID:17297143

Hayward, Scott A L; Rinehart, Joseph P; Sandro, Luke H; Lee, Richard E; Denlinger, David L

2007-03-01

343

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

344

Hibernation physiology, freezing adaptation and extreme freeze tolerance in a northern population of the wood frog.  

PubMed

We investigated hibernation physiology and freeze tolerance in a population of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA, near the northernmost limit of the species' range. Winter acclimatization responses included a 233% increase in the hepatic glycogen depot that was subsidized by fat body and skeletal muscle catabolism, and a rise in plasma osmolality that reflected accrual of urea (to 106±10 ?mol ml(-1)) and an unidentified solute (to ~73 ?mol ml(-1)). In contrast, frogs from a cool-temperate population (southern Ohio, USA) amassed much less glycogen, had a lower uremia (28±5 ?mol ml(-1)) and apparently lacked the unidentified solute. Alaskan frogs survived freezing at temperatures as low as -16°C, some 10-13°C below those tolerated by southern conspecifics, and endured a 2-month bout of freezing at -4°C. The profound freeze tolerance is presumably due to their high levels of organic osmolytes and bound water, which limits ice formation. Adaptive responses to freezing (-2.5°C for 48 h) and subsequent thawing (4°C) included synthesis of the cryoprotectants urea and glucose, and dehydration of certain tissues. Alaskan frogs differed from Ohioan frogs in retaining a substantial reserve capacity for glucose synthesis, accumulating high levels of cryoprotectants in brain tissue, and remaining hyperglycemic long after thawing. The northern phenotype also incurred less stress during freezing/thawing, as indicated by limited cryohemolysis and lactate accumulation. Post-glacial colonization of high latitudes by R. sylvatica required a substantial increase in freeze tolerance that was at least partly achieved by enhancing their cryoprotectant system. PMID:23966588

Costanzo, Jon P; do Amaral, M Clara F; Rosendale, Andrew J; Lee, Richard E

2013-09-15

345

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.

346

Petroleum refinery secondary effluent polishing using freezing processes--toxicity and organic contaminant removal.  

PubMed

A petroleum refinery secondary effluent was treated using two freezing techniques--spray freezing and unidirectional downward freezing (UDF). The freezing processes were effective to remove toxicity and total organic carbon (TOC)- and chemical oxygen demand (COD)-causing materials in the effluent. Agitation of the liquid during UDF significantly improved the impurity separation efficiency; 85 to 96% removal of TOC and COD was achieved without any pretreatment and freezing only 70% of the feed water. The treatment efficiency of the spray freezing was at the same level as that of UDF without mixing. The spray ice with longer storage time released more contaminants with early meltwater. The initial contaminant concentration of the feed water and the freezing temperatures (-10 degrees C and -25 degrees C) had no significant influence on the treatment efficiency. A small fluctuation in effluent TOC concentration caused a dramatic change in effluent toxicity (Microtox). The effective concentration (EC20) (Microtox) was effective in detecting effluent toxicity. PMID:18686927

Gao, W; Smith, D W; Habib, M

2008-06-01

347

Competitive freezing in gold nanoparticles  

NASA Astrophysics Data System (ADS)

We use molecular dynamics simulations to study the freezing of gold nanoparticles in a size range of N = 309-923 gold atoms and find the clusters freeze to a variety of structures, including icosahedra, decahedra and face-centered cubic type structures. Measurements of the rate of freezing for the different structures reveal that the icosahedral clusters form an order ofmagnitude faster than the remaining structures over the entire range of cluster sizes studied. An analysis of the structural evolution of the icosahedral and decahedral clusters during freezing events suggests that, despite the vast difference in freezing rates, the two structures both initially form the same five-fold symmetric cap, constructed from tetrahedral sub-units of face-centered cubic packed atoms. The slow rate of decahedron freezing may be caused introduction of strain into the structure as it grows along the five-fold symmetric axis of the cluster and the need to form high energy <100> facets.

Asuquo, Cletus C.; Bowles, Richard K.

2013-05-01

348

Point-of-use water treatment and diarrhoea reduction in the emergency context: an effectiveness trial in Liberia  

E-print Network

during transport and storage, shared water containers and cooking pots, scarcity of soap and contaminatedPoint-of-use water treatment and diarrhoea reduction in the emergency context: an effectiveness in current water treatment technologies, and few products are capable of treating turbid water. We describe

Scharfstein, Daniel

349

Single-Point Magnetic Resonance Imaging Study of Water Adsorption in Pellets of Zeolite 4A  

NASA Astrophysics Data System (ADS)

The water uptake process in commercial type particles of zeolite 4A has been studied using a single-point MRI method. True proton density,T1,T2, andT*2relaxation times were obtained with submillimetric resolution, overcoming the restrictions of shortT*2signals. The molecular mobility in nonequilibrium conditions has been characterized by relaxation time mapping. A clear reduction of the water sorption rate was observed by comparing MRI profiles of a loosely packed bed and gravimetric measurements of spread particles from the same sieved zeolite batch.

Prado, Pablo J.; Balcom, Bruce J.; Jama, Mohamed

1999-03-01

350

On the particle paths and the stagnation points in small-amplitude deep-water waves  

E-print Network

In order to obtain quite precise information about the shape of the particle paths below small-amplitude gravity waves travelling on irrotational deep water, analytic solutions of the nonlinear differential equation system describing the particle motion are provided. All these solutions are not closed curves. Some particle trajectories are peakon-like, others can be expressed with the aid of the Jacobi elliptic functions or with the aid of the hyperelliptic functions. Remarks on the stagnation points of the small-amplitude irrotational deep-water waves are also made.

Delia Ionescu-Kruse

2012-02-22

351

Studies on Freezing RAM Semen in Absence of Glycerol.  

NASA Astrophysics Data System (ADS)

Glycerol is widely used as a major cryoprotective agent for freezing spermatozoa of almost all species. However, it reduces fertility of sheep inseminated cervically compared with intrauterine insemination. Studies were conducted to develop a method and procedure for freezing ram semen in the absence of glycerol. Post -thaw survival of ram spermatozoa frozen in the absence of glycerol was affected by time and temperature after collection and before dilution and time after dilution and before freezing. Increase in time at 5^ circC before or after dilution and before freezing increased both post-thaw motility and number of cells passing through Sephadex filter. A cold dilution method was developed. Slow cooling of fresh ram semen and diluting at 5^circ C 2-3 hr. after collection, then freezing 1 hr. after dilution improved both post-thaw motility and number of cells passing through Sephadex filter compared with immediate dilution at 30-37^circC after collection and freezing 3-4 hr. later (P < 0.05). An extender was developed to freeze ram semen in the absence of glycerol. An increase in post-thaw motility was obtained when semen was extended in TES titrated with Tris to pH 7.0 (TEST) and osmotic pressure of 375-400 mOsm/kg, containing 25-30% (v/v) egg yolk and 10% (v/v) maltose. A special device (boat) for freezing was constructed to insure the same height of the sample above LN _2 and thus the same freezing rate from freeze to freeze. Freezing of semen in 0.25cc straws at 5-10 cm above LN_2 (73.8 to 49.5 ^circC/min) yielded higher post-thaw motility than the rates resulted from freezing at 15 cm above LN_2 or 1 cm above LN _2. Faster Thawing in 37^ circC water for 30 sec. (7.8^ circC/sec.) increased post-thaw motility compared with slower thawing in 5 or 20^circ C water (P < 0.05). A lambing rate of 52.2% was obtained in one fertility trial conducted with ram semen frozen without glycerol and 17.1% in a second trial. One injection (IM) of 15 mg PGF_{2alpha}/ewe for estrus synchronization during breeding season resulted in higher heat response and lambing rate than two injections given 10 days apart.

Abdelnaby, Abdelhady Abdelhakeam

1988-12-01

352

Comparison of Point-of-Use Technologies for Emergency Disinfection of Sewage-Contaminated Drinking Water ?  

PubMed Central

Four point-of-use disinfection technologies for treating sewage-contaminated well water were compared. Three systems, based on flocculant-disinfectant packets and N-halamine chlorine and bromine contact disinfectants, provided a range of 4.0 to >6.6 log10 reductions (LR) of naturally occurring fecal indicator and heterotrophic bacteria and a range of 0.9 to >1.9 LR of coliphage. PMID:19767479

McLennan, S. Devin; Peterson, Lauren A.; Rose, Joan B.

2009-01-01

353

Economic incentives for the control of agricultural non-point source water pollution  

Microsoft Academic Search

The principal objective of this study is to analyze incentive-based policy alternatives for their potential to address agricultural non-point source water pollution in a setting characterized by input market distortions. The theoretical model incorporates both the externality and the second-best nature of the problem. Policy alternatives considered include first-best policies such as taxes and standards on estimated effluent or on

1992-01-01

354

Economic incentives for the control of agricultural non-point-source water pollution  

Microsoft Academic Search

The principal objective of this study is to analyze incentive-based policy alternatives for their potential to address agricultural non-point-source water pollution in a setting characterized by input market distortions. Policy alternatives considered include first-best policies such as taxes and standards on estimated effluent or on all inputs to effluent generation, as well as less-efficient tools including uniform taxes and taxes

1991-01-01

355

Ground-water conditions at the Veterans Facility, Castle Point, New York  

USGS Publications Warehouse

The rock aquifers in the vicinity of the Castle Point Veterans Hospital yield limited quantities of water which, in general, are sufficient for domestic and farm purposes only. The possibility of obtaining the stated quantity requirements of about 200,000 gallons daily or more from the bedrock formations seems poor with the exception of the Wappinger limestone underlying the Fishkill Valley three miles to the south.

Brashears, M.L., Jr.

1950-01-01

356

The effect of water contamination on the dew-point temperature scale realization with humidity generators  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to study the effect of contaminated water in the context of humidity generators. Investigation of different methods to determine the drop in dew-point temperature due to contamination and experiments on actual contamination rates are reported. Different methods for calculating the dew-point temperature effect from electrical conductivity and density measurements are studied with high-purity water and aqueous solutions of NaCl and LiCl. The outcomes of the calculation methods are compared with the results of direct humidity measurements. The results show that the often applied Raoult's law based calculation method is in good agreement with other methods. For studying actual contamination, water samples were kept in glass, plastic, copper and stainless-steel vessels for up to 13 months to investigate natural ionic and organic contamination in vessels with different wall materials. The amount of ionic contamination was found to be higher in copper and glass vessels than in stainless-steel and plastic vessels. The amount of organic contamination was found to be highest in the plastic vessel. In all the cases, however, the corresponding drop in dew-point temperature due to natural contamination was found to be below 0.1 mK. The largest rate of change of dew-point temperature was 26 µK/month. Thus, if proper cleanness is maintained in a humidity generator the effect of contamination of water in the saturator is insignificant compared with the major uncertainty components even in the most accurate generators today.

Vilbaste, M.; Heinonen, M.; Saks, O.; Leito, I.

2013-08-01

357

Performance Characteristics of an Isothermal Freeze Valve  

SciTech Connect

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

Hailey, A.E.

2001-08-22

358

Water-cooled end-point boundary temperature control of hot strip via dynamic programming  

SciTech Connect

In this paper, an end-point boundary temperature control approach for runout table cooling used in hot strip mills is presented. The system relies on a linearized model for describing heat radiated to the environment and heat transferred to cooling water. At first, a conventional feedforward control design to control the temperature at the end-point boundary, the only measurable controlled parameter, is presented. Subsequently, a modified control scheme which uses dynamic programming to minimize the temperature error at the end-point boundary is discussed in detail. System performance analysis via simulation is presented for both control schemes. Simulation results show that temperature error minimization by dynamic programming improves system performance.

Samaras, N.S. [Danieli Automation, Pittsburgh, PA (United States)] [Danieli Automation, Pittsburgh, PA (United States); Simaan, M.A. [Univ. of Pittsburgh, PA (United States). Dept. of Electrical Engineering] [Univ. of Pittsburgh, PA (United States). Dept. of Electrical Engineering

1998-11-01

359

Reliable determination of freeze-concentration using DSC  

Microsoft Academic Search

The objective of this study was to determine the feature of a DSC endotherm that can be most reliably used to determine the composition of a freeze-concentrate. Samples (3–10mg) of sucrose in water (0–60%, w\\/v) were frozen and then heated (at 0.2–2.0°C\\/min) on a DSC. The peak (Tpeak) and offset (Toffset) temperatures were obtained from the melt endotherms. A freezing

Bakul S. Bhatnagar; Stephane Cardon; Michael J. Pikal; Robin H. Bogner

2005-01-01

360

Freezing behavior of potato ( Solanum tuberosum ) tubers in soil  

Microsoft Academic Search

Volunteer potatoes are a major weed problem in potato rotations in regions with mild winter soil temperatures. Freezing dynamics\\u000a of potato tubers in air have been previously reported, but freezing dynamics of tubers in soil may differ due to ice nucleation\\u000a sites and soil water associated with soil. Laboratory experiments conducted in hydrated and dry soil columns and field experiments

R. A. Boydston; M. D. Seymour; C. R. Brown; A. K. Alva

2006-01-01

361

Tracking Non-point Fecal Pollution in the Guadalupe River: Distinguishing Urban and Rural Influences upon Water Quality  

E-print Network

, Assistant Professor University of Houston - Victoria Non-point fecal pollution is a problem in water bodiesTracking Non-point Fecal Pollution in the Guadalupe River: Distinguishing Urban and Rural Influences upon Water Quality Matthew Boyett University of Houston - Victoria boyettmr@uhv.edu Dmitri Sobolev

362

Experimentally proven liquid-liquid critical point of dilute glycerol-water solution at 150 K  

NASA Astrophysics Data System (ADS)

The experimental and theoretical studies of supercooled liquid water strongly suggest that the two liquid waters and their liquid-liquid critical point (LLCP) exist at low temperature. However, the decisive experimental evidence of the LLCP has not been obtained because of the rapid crystallization of liquid water in the "no-man's land." Here, we observed experimentally the pressure-induced polyamorphic transition in the dilute glycerol-water solution which relates to the water polyamorphism. We examined the effect of the glycerol concentration on the liquid-liquid transition, and found its LLCP around 0.12-0.15 mole fraction, 0.03-0.05 GPa, and ˜150 K. A 150 K was above, or around, the recently recognized glass transition temperatures of amorphous ices, and the crystallization did not occur, indicating that the direct observation of LLCP is feasible. The low-temperature LLCP has implication to the argument of the relation between the interaction potential of water molecule and the polyamorphic phase diagram.

Suzuki, Yoshiharu; Mishima, Osamu

2014-09-01

363

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

2013-10-01

364

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2011 CFR

...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

2011-01-01

365

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2013 CFR

...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

2013-01-01

366

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2014 CFR

...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

2014-01-01

367

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2010 CFR

...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

2010-01-01

368

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2012 CFR

...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

2012-01-01

369

Polarizable six-point water models from computational and empirical optimization.  

PubMed

Tröster et al. (J. Phys. Chem B 2013, 117, 9486-9500) recently suggested a mixed computational and empirical approach to the optimization of polarizable molecular mechanics (PMM) water models. In the empirical part the parameters of Buckingham potentials are optimized by PMM molecular dynamics (MD) simulations. The computational part applies hybrid calculations, which combine the quantum mechanical description of a H2O molecule by density functional theory (DFT) with a PMM model of its liquid phase environment generated by MD. While the static dipole moments and polarizabilities of the PMM water models are fixed at the experimental gas phase values, the DFT/PMM calculations are employed to optimize the remaining electrostatic properties. These properties cover the width of a Gaussian inducible dipole positioned at the oxygen and the locations of massless negative charge points within the molecule (the positive charges are attached to the hydrogens). The authors considered the cases of one and two negative charges rendering the PMM four- and five-point models TL4P and TL5P. Here we extend their approach to three negative charges, thus suggesting the PMM six-point model TL6P. As compared to the predecessors and to other PMM models, which also exhibit partial charges at fixed positions, TL6P turned out to predict all studied properties of liquid water at p0 = 1 bar and T0 = 300 K with a remarkable accuracy. These properties cover, for instance, the diffusion constant, viscosity, isobaric heat capacity, isothermal compressibility, dielectric constant, density, and the isobaric thermal expansion coefficient. This success concurrently provides a microscopic physical explanation of corresponding shortcomings of previous models. It uniquely assigns the failures of previous models to substantial inaccuracies in the description of the higher electrostatic multipole moments of liquid phase water molecules. Resulting favorable properties concerning the transferability to other temperatures and conditions like the melting of ice are also discussed. PMID:24437570

Tröster, Philipp; Lorenzen, Konstantin; Tavan, Paul

2014-02-13

370

Studies of water velocity in the capillary fringe: the point velocity probe.  

PubMed

The point velocity probe (PVP) is a device that can measure groundwater velocity at the centimeter scale, and unlike devices that measure velocity within well screens, the PVP operates while in direct contact with the porous medium. Because of this feature, it was postulated that the PVP could be effective in measuring velocity within the capillary fringe. This hypothesis was tested using a laboratory flow-through cell filled with a medium-fine sand from Canadian Forces Base Borden. The cell was constructed to simulate conditions such that the PVP was positioned from 2.5 cm below the water table to 79 cm above the water table. As the water table was lowered, the PVP gave highly consistent values of velocity over the range equivalent to 2.5 cm below the water table to 44 cm above the water table, the approximate extent of the capillary fringe. The average measured velocity was 11.3 cm/d +/- 11.6%, somewhat higher than that calculated based on the measured discharge through the cell (7.5 cm/d +/- 5.5%). With a further decline in the water table there was a progressive decrease in the measured velocity values, consistent with the declining hydraulic conductivity as the sand material drained. Readings could not be made beyond about 57 cm, where the water content was approximately 75% of saturation. These experiments showed that the PVP is capable of measuring groundwater velocity within the saturated zone above the water table and possibly into the unsaturated zone. Currently, this is the only instrument available with this capability. PMID:19664049

Berg, S J; Gillham, R W

2010-01-01

371

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

372

Understanding Slag Freeze Linings  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

373

Heat transfer and operating conditions for freeze concentration in a liquid–solid fluidized bed heat exchanger  

Microsoft Academic Search

Freeze concentration involves concentrating liquids partially by freezing water out of the solution thus leaving behind a concentrate rich in its solutes. It is an expensive process that could benefit from alternative approaches that are more cost-effective. In this paper, freeze concentration is studied inside a fluidized bed heat exchanger (FBHE), which is a cheaper alternative to the conventionally used

Boaz Habib; Mohammed Farid

2006-01-01

374

Precision and accuracy of doubly labeled water energy expenditure by multipoint and two-point methods.  

PubMed

Two-point or multipoint, that is the question. Equations are developed to compare the precision and accuracy of energy expenditure, as estimated from doubly labeled water data, when analyzed by the multipoint and two-point methods. The equations convert the enrichments of deuterium and oxygen-18 into their ratio and product, quantities that are less covariant than the two isotopes themselves are. This is important not only for estimating the precision but also as a graphical aid, since the ratios of the enrichments model carbon dioxide production, whereas the enrichment products largely model water turnover. Using data on 12 human subjects from the United Kingdom and The Gambia as examples, the combined precision and accuracy of the multipoint method (CV 3.6%) was found to be appreciably better than the two-point method (CV 5.4%). The bias in the multipoint estimate of body pool size would need to be three times as large as was observed before it canceled out the better precision. PMID:1443129

Cole, T J; Coward, W A

1992-11-01

375

Water polarization induced by thermal gradients: The extended simple point charge model (SPC/E)  

NASA Astrophysics Data System (ADS)

We investigate the non-equilibrium response of extended simple point charge (SPC/E) water to thermal gradients. Using non-equilibrium molecular dynamics simulations, we show that SPC/E water features the thermo-polarization orientation effect, namely, water becomes polarized as a response to a thermal gradient. The polarization field increases linearly with the thermal gradient, in agreement with predictions of non-equilibrium thermodynamics theory. This observation confirms the generality of the thermo-polarization effect, first reported using the Modified Central Force Model (MCFM), and shows this physical effect is present irrespective of the water model details, in particular, dipole moment magnitude and model flexibility. The magnitude of the effect is the same for both models, although the sign of the electrostatic field is reversed in going from the MCFM to the SPC/E model. We further analyze the impact that the molecular geometry and mass distribution has on the magnitude of the polarization. Our results indicate that the thermo-polarization effect should be observed in a wide range of polar fluids, including fluids where hydrogen bonding is not present. Using various molecular models, we show that the polarization of these fluids under appropriate thermodynamic conditions can be of the same order or stronger than in water.

Armstrong, J. A.; Bresme, F.

2013-07-01

376

Water polarization induced by thermal gradients: the extended simple point charge model (SPC/E).  

PubMed

We investigate the non-equilibrium response of extended simple point charge (SPC/E) water to thermal gradients. Using non-equilibrium molecular dynamics simulations, we show that SPC/E water features the thermo-polarization orientation effect, namely, water becomes polarized as a response to a thermal gradient. The polarization field increases linearly with the thermal gradient, in agreement with predictions of non-equilibrium thermodynamics theory. This observation confirms the generality of the thermo-polarization effect, first reported using the Modified Central Force Model (MCFM), and shows this physical effect is present irrespective of the water model details, in particular, dipole moment magnitude and model flexibility. The magnitude of the effect is the same for both models, although the sign of the electrostatic field is reversed in going from the MCFM to the SPC/E model. We further analyze the impact that the molecular geometry and mass distribution has on the magnitude of the polarization. Our results indicate that the thermo-polarization effect should be observed in a wide range of polar fluids, including fluids where hydrogen bonding is not present. Using various molecular models, we show that the polarization of these fluids under appropriate thermodynamic conditions can be of the same order or stronger than in water. PMID:23822311

Armstrong, J A; Bresme, F

2013-07-01

377

Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy  

Microsoft Academic Search

SUMMARY A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households

R. E. QUICK; L. V. VENCZEL; E. D. MINTZ; L. SOLETO; J. APARICIO; M. GIRONAZ; L. HUTWAGNER; K. GREENE; C. BOPP; K. MALONEY; D. CHAVEZ; M. SOBSEY; R. V. TAUXE

1999-01-01

378

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

NASA Astrophysics Data System (ADS)

Water triple point cells are essential for realization of the International Temperature Scale of 1990 (ITS-90). There is some evidence that achieving the ultimate performance of water triple point cells may be restricted by the variation in the position of the platinum resistance thermometer at the bottom of the re-entrant well, and that the variation in position is not completely compensated for by correction to zero measurement sensing current. This comparative study focused on the use of quartz bushes (tubular sleeves around the thermometer) of two different lengths, to improve the thermal contact and to help locate the thermometer. It shows that an improvement in repeatability of the resistance readings was achieved. The experiments were conducted over a five-week period using a standard platinum resistance thermometer, a one water cell, and two different lengths of quartz bushes. The resistance measurements were performed using an Automatic Systems Laboratories F900 resistance bridge. A description of the experiment and results is given. Significant improvement in the repeatability of the measurement of resistance was observed (factor >2) when quartz bushes were used.

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

2010-09-01

379

Assessing Impurities in Triple-Point-of-Water Cells Using a Capacitance Conductivity Test  

NASA Astrophysics Data System (ADS)

Chemical analysis of old triple-point-of-water (TPW) cells has shown that the dominant impurities in the water are the principal constituents of borosilicate glass, which suggests the long-term downward drift observed in the realized triple-point temperature of TPW cells is caused by gradual dissolution of the glass containers. Because some of the glass constituents contribute to the electrical conductivity of the water, measurement of the conductivity provides a possible means for monitoring the long-term drift of TPW cells. This paper investigates the utility of a conductivity measurement, based on the measurement of a capacitor using the TPW cell as a dielectric, as a non-destructive means for monitoring the long-term stability of cells. The measurement exploits the cylindrical geometry of the cell and uses a two-terminal-pair coaxial electrical definition of capacitance. The results include estimates of the sensitivity of the method and examples of the long-term behavior of TPW cells, some as old as 38 years and monitored for periods of up to 10 years. It is found that the conductivity measurements correlate well with the cell age, with the drift rates increasing with time, as expected from the chemical model of glass dissolution. Measurements of temperature differences between cells show the technique can detect changes as small as , and therefore the method is a useful means of monitoring TPW cells.

Yan, X. K.; White, D. R.; Hao, X. M.; Yu, Z. J.; Edgar, H.; Duan, Y. N.

2015-03-01

380

Temporal and spatial variation of waterborne point-of-use 222Rn in three water distribution systems.  

PubMed

Three water supply systems in Iowa were studied to examine temporal variation of 222Rn at the point of entry and the point of use. For the three towns, 71, 9, and 0% of the maximum point-of-use 222Rn concentrations were significantly higher than the point-of-entry 222Rn concentrations. Homes connected to older water mains in two of the towns had higher 222Rn concentrations than those connected to newer water mains. In one town, the waterborne 222Rn concentrations in the home were related to the home's location along an old water main. The increase in 222Rn concentrations, after the water leaves the water plant, were attributed to radium deposits in the water distribution system. In addition, the water plant's radium laden iron filters contributed 7 Bq L-1 and 60 Bq L-1 of 222Rn to the finished water in What Cheer, Iowa, and Wellman, Iowa, respectively. Backwashing schedules in the water treatment systems greatly affected point-of-entry 222Rn concentrations. The results of this study have important implications for 222Rn sampling, required for regulatory compliance. PMID:9450593

Fisher, E L; Fuortes, L J; Ledolter, J; Steck, D J; Field, R W

1998-02-01

381

Anchoring the water dimer potential energy surface with explicitly correlated computations and focal point analyses  

NASA Astrophysics Data System (ADS)

Ten stationary points on the water dimer potential energy surface have been characterized with the coupled-cluster technique which includes all single and double excitations as well as a perturbative approximation of triple excitations [CCSD(T)]. Using a triple-? basis set with two sets of polarization functions augmented with higher angular momentum and diffuse functions [TZ2P(f,d)+dif], the fully optimized geometries and harmonic vibrational frequencies of these ten stationary points were determined at the CCSD(T) theoretical level. In agreement with other ab initio investigations, only one of these ten stationary points is a true minimum. Of the other nine structures, three are transition structures, and the remaining are higher order saddle points. These high-level ab initio results indicate that the lowest lying transition state involved in hydrogen interchange is chiral, of C1 symmetry rather than Cs as suggested by recently developed 6D potential energy surfaces. The one- and n-particle limits of the electronic energies of these ten stationary points were probed by systematic variation of the atomic orbital basis sets and the treatment of electron correlation within the framework of the focal-point analysis of Allen and co-workers. The one-particle limit was approached via extrapolation of electronic energies computed with the augmented correlation consistent basis sets (aug-cc-pVXZ, X=D-6), and, independently, by estimating the basis set incompleteness effect with the explicitly-correlated second-order Møller-Plesset method (MP2-R12). Electron correlation was evaluated at levels as high as the Brueckner coupled cluster method with double excitations and perturbatively treated triple and quadruple excitations [BD(TQ)]. Core correlation and relativistic effects were also assessed. Consideration of the aforementioned electronic effects as well as basis set superposition error leads to an estimate of 21.0 kJ mol-1 for the electronic dissociation energy of (H2O)2.

Tschumper, Gregory S.; Leininger, Matthew L.; Hoffman, Brian C.; Valeev, Edward F.; Schaefer, Henry F.; Quack, Martin

2002-01-01

382

TESTING & EVALUATION OF POINT-OF-USE (POU) AND POINT-OF-ENTRY (POE) TECHNOLOGIES FOR DRINKING WATER TREATMENT  

EPA Science Inventory

Centralized water treatment and distribution are still the recommended methods for producing safe drinking water. But in reality this approach cannot and will not meet the needs of millions of homes in both the U.S. and around the world, which do not have the option of connectin...

383

Impacts by point and diffuse micropollutant sources on the stream water quality at catchment scale  

NASA Astrophysics Data System (ADS)

The water quality of surface waters is threatened by multiple anthropogenic pollutants and the large variety of pollutants challenges the monitoring and assessment of the water quality. The aim of this study was to characterize and quantify both point and diffuse sources of micropollutants impacting the water quality of a stream at catchment scale. Grindsted stream in western Jutland, Denmark was used as a study site. The stream passes both urban and agricultural areas and is impacted by severe groundwater contamination in Grindsted city. Along a 12 km reach of Grindsted stream, the potential pollution sources were identified including a pharmaceutical factory site with a contaminated old drainage ditch, two waste deposits, a wastewater treatment plant, overflow structures, fish farms, industrial discharges and diffuse agricultural and urban sources. Six water samples were collected along the stream and analyzed for general water quality parameters, inorganic constituents, pesticides, sulfonamides, chlorinated solvents, BTEXs, and paracetamol and ibuprofen. The latter two groups were not detected. The general water quality showed typical conditions for a stream in western Jutland. Minor impacts by releases of organic matter and nutrients were found after the fish farms and the waste water treatment plant. Nickel was found at concentrations 5.8 - 8.8 ?g/l. Nine pesticides and metabolites of both agricultural and urban use were detected along the stream; among these were the two most frequently detected and some rarely detected pesticides in Danish water courses. The concentrations were generally consistent with other findings in Danish streams and in the range 0.01 - 0.09 ?g/l; except for metribuzin-diketo that showed high concentrations up to 0.74 ?g/l. The groundwater contamination at the pharmaceutical factory site, the drainage ditch and the waste deposits is similar in composition containing among others sulfonamides and chlorinated solvents (including vinyl chloride). Vinyl chloride concentrations surpassed Danish stream water quality criteria with a factor 10. The largest chemical impact occurs at the reach downstream Grindsted city revealing that the main contaminant groundwater discharge zones are found here. The contaminant plume from the factory site north of the stream is known to impact the stream whereas the impact by the old landfill south of the stream remains to be assessed. A conceptual model of the chemical impacts by the identified sources was made, and high impact was assigned to the contaminant plume from the factory site and to the diffuse sources of urban-use and agricultural pesticides. The next step will be a quantification of the sources, which will be presented at the conference.

Petersen, M. F.; Eriksson, E.; Binning, P. J.; Bjerg, P. L.

2012-04-01

384

Freeze Shoe Sampler for the Collection of Hyporheic Zone Sediments and Porewater.  

PubMed

The Starr and Ingleton (1992) drive point piston sampler (DPPS) design was modified by fitting it with a Murphy and Herkelrath (1996) type sample-freezing drive shoe (SFDS), which uses liquid carbon dioxide as a cryogen. Liquid carbon dioxide was used to freeze sediments in the lower 0.1?m of the core and the drive-point piston sealed the core at the top preserving the reductive-oxidation (redox) sensitive sediments from the atmosphere and maintaining natural stratigraphy. The use of nitrogen gas to provide positive pressure on the gas system blocked the ingress of water which froze on contact with the cryogen thus blocking the gas lines with ice. With this adaptation to the gas system cores could be collected at greater depths beneath the static water level. This tool was used to collect intact saturated sediment cores from the hyporheic zone of the tidally influenced Fraser River in Vancouver, British Columbia, Canada where steep geochemical and microbial gradients develop within the interface between discharging anaerobic groundwater and recharging aerobic river water. In total, 25 cores driven through a 1.5?m sampling interval were collected from the river bed with a mean core recovery of 75%. The ability to deploy this method from a fishing vessel makes the tool more cost effective than traditional marine-based drilling operations which often use barges, tug boats, and drilling rigs. PMID:24825508

Bianchin, M; Smith, L; Beckie, R

2015-03-01

385

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

A sinkhole formed in a roadway caused traffic to detour around it while it is filled in, stabilized and repaved. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pumped water to...

386

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pumped water to irrigate their plants for protection from the cold temperatures. The sinkholes destroyed homes, roads and se...

387

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

The entire root perimeter of this tree collapsed in response to subsidence activity. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pumped water to irrigate their plants for pr...

388

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

Sinkholes affect roadway safety and require constant maintenance and monitoring. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pumped water to irrigate their plants for p...

389

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

Sinkholes damage roadways and require constant maintenance for road safety. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pumped water to irrigate their plants for protection ...

390

Non-point contamination homogenizes the water quality of pampean streams.  

PubMed

The aim of this research was to study the effects on streams water quality of non-point contamination as agriculture and cattle farming activities at a basin with pampean characteristics located at the upper Reconquista River Basin. Eight reaches with different uses in their neighboring zones were selected with the proposed to detect differences at the water quality among them. SRP range was 0-0.60 mgP.PO (4) (-3) /L, ammonia 1-137.3 ?gN-NH4(+)/L and nitrate 0-4.15 mgN-NO(3) (-)/L. There was high similitude and homogeneous physicochemical characteristics at the different reaches of the streams. The high levels of dissolved nutrients showed similar eutrophication conditions at the streams. PMID:21617938

Vilches, Carolina; Giorgi, Adonis; Mastrángelo, Martina; Ferrari, Lucrecia

2011-08-01

391

Atmospheric Pressure Glow Discharge for Point-of-Use Water Treatment  

NASA Astrophysics Data System (ADS)

Treatment of biological and chemical contaminants is an area of growing global interest where atmospheric pressure plasmas can make a significant contribution. Addressing key challenges of volume processing and operational cost, a large volume 162 MHz coaxial air-plasma source has been developed.footnotetextByrns (2012) J. Phys. D: Appl. Phys. 45 (2012) 195204 Because of VHF ballasting effects, the electric discharge is maintained at a steady glow, allowing formation of critical non-equilibrium chemistry. High densities, ne = 10^11-10^12, have been recorded. The atmospheric nature of the device permits straightforward and efficient treatment of water samples. [H^+] concentrations in 150 milliliter tap water samples have been shown to increase by 10^5 after five minutes of discharge exposure. Recent literature has demonstrated that increasing acidity is strongly correlated with a solution's ability to deactivate microbial contaminants.footnotetextTraylor (2011) J. Phys. D: Appl. Phys. 44 (2011) 472001 The work presented here will explore the impact of treatment gas, system configuration, and power density on water disinfection and PFC abatement. An array of plasma diagnostics, including OES and electrical measurements, are combined with post-process water analysis, including GC-MS and QT analysis of coliform and E.coli bacteria. Development of volume processing atmospheric plasma disinfection methods offers promise for point-of-use treatments in developing areas of the world, potentially supplementing or replacing supply and weather-dependent disinfection methods.

Lindsay, Alexander; Byrns, Brandon; Shannon, Steven; Knappe, Detlef

2012-10-01

392

Mice use start point orientation to solve spatial problems in a water T-maze.  

PubMed

Behavioral work has demonstrated that rats solve many spatial problems using a conditional strategy based on orientation at the start point. The present study assessed whether mice use a similar strategy and whether the strategy would be affected by the poorer directional sensitivity of mice. In Experiment 1, mice were trained on a response, a direction or one of two place problems to locate a hidden platform in a water T-maze located in two positions. In the response task, mice made a right (or left) turn from two different start points located 180° apart. In the direction task, the maze was shifted (to the left or right) and the start points rotated by 180° across trials, but the platform was in a constant direction relative to room cues. In the translation place task, the mice were trained to locate the platform in a fixed location relative to extra-maze cues when the maze was shifted across trials, but the orientation of the start arm did not change. In the rotation place task, the mice were trained to locate the platform in a fixed location when the maze was shifted and the start points rotated by 90° across trials. As previously reported with rats, mice had difficulty solving the translation place problem compared with the other three problems. Unlike rats, mice learned the direction problem in significantly fewer trials than the rotation problem. This difference between acquisition of the direction and rotation problems was replicated in Experiment 2. The difficulty mice have in discriminating start point orientations that are 90° apart as opposed to 180° apart can be attributed to the broader firing ranges of HD cells in mice compared with rats. PMID:25060577

Cahill, Shaina P A; Fifield, Kathleen E; Thorpe, Christina M; Martin, Gerard M; Skinner, Darlene M

2015-01-01

393

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

PubMed

The objective of this study was to elucidate effects of formulation and process variables on the physical forms of freeze-dried myo-inositol. Physical properties of myo-inositol in frozen solutions, freeze-dried solids, and cooled heat-melt solids were characterized by powder X-ray diffraction (PXRD), thermal analysis (differential scanning calorimetry [DSC] and thermogravimetric), and simultaneous PXRD-DSC analysis. Cooling of heat-melt myo-inositol produced two forms of metastable anhydrate crystals that change to stable form (melting point 225 °C-228 °C) with transition exotherms at around 123 °C and 181 °C, respectively. Freeze-drying of single-solute aqueous myo-inositol solutions after rapid cooling induced crystallization of myo-inositol as metastable anhydrate (transition at 80 °C-125 °C) during secondary drying segment. Contrarily, postfreeze heat treatment (i.e., annealing) induced crystallization of myo-inositol dihydrate. Removal of the crystallization water during the secondary drying produced the stable-form myo-inositol anhydrate crystal. Shelf-ramp slow cooling of myo-inositol solutions resulted in the stable and metastable anhydrous crystal solids depending on the solute concentrations and the solution volumes. Colyophilization with phosphate buffer retained myo-inositol in the amorphous state. Crystallization in different process segments varies crystal form of freeze-dried myo-inositol solids. PMID:24916801

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

2014-08-01

394

Significant variability among bulls in the sperm membrane permeability for water and glycerol: possible implications for semen freezing protocols for individual males.  

PubMed

The aim of this study was to test the hypothesis that bulls have significant intra-individual differences in the hydraulic conductivity (L(p)) and permeability coefficient for glycerol (P(s)) of the sperm cell membrane. The permeability parameters were determined at 22, 10, and 0 degrees C of sperm from 7 Holstein Frisian artificial insemination (AI) bulls, using four ejaculates per bull. A stopped-flow approach was applied to provide temporal resolution sufficient to measure rapid cell volume changes under anisosmotic conditions in the absence or presence of glycerol. This technique utilizes a concentration-dependent self-quenching entrapped fluorophore. The resulting cell volume changes were used in three-parameter fitting calculations to compute L(p) in the absence glycerol, and L(p) in the presence of glycerol (L(p)(gly)) and P(s). Averaged over all bulls, L(p) in the absence of glycerol was 0.28+/-0.01, 0.15+/-0.01 and 0.10+/-0.01 microm min(-1)atm(-1) (mean+/-SD) at 22, 10 and 0 degrees C, respectively, yielding an Arrhenius activation energy (E(a)) of 7.39 kcal/mol. The average L(p)(gly) value at 22 degrees C, was 3.8 times lower than L(p) in the absence of glycerol (P<0.05). L(p)(gly), P(s), and the reflection coefficient (sigma) at 22 degrees C were 0.073+/-0.015 microm min(-1)atm(-1), 0.80+/-0.33 x 10(-3)cm min(-1), and 0.92+/-0.10 (mean+/-SD), respectively. Subsequent experiments were performed at 10 and 0 degrees C. Activation energies for L(p)(gly) and P(s) were 10.08 and 8.77 kcal/mol, respectively. The significant differences between individual bulls in L(p) and P(s) indicate that individual males may require individual adjustments of the cooling protocol. Application of these data in a theoretical model to simulate the osmotic events during freezing resulted in predicted optimal cooling rates in the range of published empirical values. PMID:17097627

Chaveiro, A; Liu, J; Engel, B; Critser, J K; Woelders, H

2006-12-01

395

Radio continuum, ammonia, and water maser observations of bright, unassociated IRAS point sources  

NASA Astrophysics Data System (ADS)

We present matching-beam 6 and 2 cm radio continuum observations made with the Very Large Array, and ammonia and water maser observations made at the Haystack Observatory of 12 Infrared Astronomical Satellite (IRAS) point sources selected from the survey of Scalise, Rodriguez, & Mendoza-Torres (1989) of bright, unassociated IRAS point sources. These sources have 60 or 100 micrometer flux densities in excess of 103 Jy and have no previous reference in any of the 37 catalogs considered for association of IRAS sources with known sources. Six of the 12 sources have associated radio continuum, ammonia, and water maser emission, and all of them show at least one of these three emissions. In all sources detected, the ammonia is warm (T approximately 20 K) and suggests the association of dense molecular gas with embedded heating sources. It is argued that all sources in the sample could be associated with time-variable H2O maser emission. The radio and far-infrared data appear to indicate that these sources are star-forming regions, powered by a late O or early B-type star. Several of the sources of lower luminosity (approximately 5 x 103 solar luminosity) appear to have ionizing photon fluxes in excess of those expected for a zero-age main-sequence star. Possible explanations for this discrepancy are discussed.

Miralles, Mari Paz; Rodriguez, Luis F.; Scalise, Eugenio

1994-05-01

396

Tracing Cytoplasmic Ca2+ Ion and Water Access Points in the Ca2+-ATPase  

PubMed Central

Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) transports two Ca2+ 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 Ca2+ 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 Ca2+-free state of the transporter. Additional molecular dynamics simulations performed on a Ca2+-bound state of SERCA reveal a water-filled pathway that may be used by the Ca2+ 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 Ca2+ 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 Ca2+ translocation pathway toward the transmembrane ion-binding sites. PMID:22339863

Musgaard, Maria; Thøgersen, Lea; Schiøtt, Birgit; Tajkhorshid, Emad

2012-01-01

397

Demonstration and evaluation of germicidal UV-LEDs for point-of-use water disinfection.  

PubMed

Ultraviolet (UV) irradiation is a common disinfection option for water treatment in the developed world. There are a few systems installed in developing countries for point-of-use treatment, but the low-pressure mercury lamps currently used as the UV irradiation source have a number of sustainability issues including a fragile envelope, a lifetime of approximately one year, and they contain mercury. UV light emitting diodes (LEDs) may offer solutions to many of the sustainability issues presented by current UV systems. LEDs are small, efficient, have long lifetimes, and do not contain mercury. Germicidal UV LEDs emitting at 265 nm were evaluated for inactivation of E. coli in water and compared to conventional low-pressure UV lamps. Both systems provided an equivalent level of treatment. A UV-LED prototype was developed and evaluated as a proof-of-concept of this technology for a point-of-use disinfection option, and the economics of UV-LEDs were evaluated. PMID:20375477

Chatterley, Christie; Linden, Karl

2010-09-01

398

Nuclear freeze: myths and realities  

SciTech Connect

A nuclear freeze would create serious problems for US strategic and political interests, and would not achieve the professed goal of a lower probability of nuclear war. It could increase strategic instability and reinforce the morally questionable Mutual Assured Destruction (MAD) approach of using civilian populations as hostages. Compliance would not be verifiable, and Soviet compliance would be doubtful. A review of the strategic and political implications and the basic assumptions of freeze advocates suggests that the movement has proved useful in forcing advocates of other positions to sharpen and refine their arguments. The challenge for freeze opponents is to make it clear to the public that the proposed freeze would benefit the Soviets and to offer viable alternatives for nuclear policy. 15 references.

Weinrod, W.B.

1983-03-03

399

Cloud point extraction for speciation of chromium in water samples by electrothermal atomic absorption spectrometry.  

PubMed

A new method based on the cloud point extraction (CPE) separation and electrothermal atomic absorption spectrometry (ETAAS) detection was proposed for the determination of chromium species. When the system temperature is higher than the cloud point extraction temperature (CPT) of selected surfactant p-octyl polyethyleneglycolphenyether (Triton X-100), the complex of Cr(VI) with dibromophenylfluorone (Br-PF) could enter surfactant-rich phase, whereas the Cr(III) remained in aqueous phase. Thus, an in situ separation of Cr(VI) and Cr(III) could be realized. Cr(VI) in surfactant-rich phase was analyzed by ETAAS and Cr(III) was calculated by subtracting of Cr(VI) from the total chromium which was directly determined by ETAAS. The main factors affecting the cloud point extraction, such as pH, concentration of Br-PF and Triton X-100, equilibration temperature and time, were investigated systematically. Under the optimized conditions, the quantitation limit for Cr(VI) as low as 0.01 microg/L was obtained by preconcentrating a 10 mL sample solution, and the relative standard deviation (n=6, c=2.0 microg/L) was 2.6%. The proposed method was applied to the speciation of chromium in different water samples and the recoveries in the range of 98.9-105.3% were obtained by spiking the real samples. In order to verify the accuracy of the method, a certified reference water sample was analyzed and the results obtained were in good agreement with the certified values. PMID:15707631

Zhu, Xiashi; Hu, Bin; Jiang, Zucheng; Li, Mingfang

2005-02-01

400

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

Code of Federal Regulations, 2013 CFR

...2) The design and application of the point-of-entry devices must consider the tendency for increase in heterotrophic bacteria concentrations in water treated with activated carbon. It may be necessary to use frequent backwashing,...

2013-07-01

401

Freezing of Martian streams under climatic conditions  

NASA Technical Reports Server (NTRS)

The valley networks of Mars are widely believed to have formed at a time when climatic conditions on the planet were significantly different from those that currently prevail. This view arises from the following observations: (1) the valleys form integrated branching networks which suggests fluid drainage, and water is the most plausible fluid, (2) the present atmosphere contains only minute amounts of water, (3) the networks appear to be more akin to terrestrial valleys that are eroded by streams of modest discharges than features that form by catastrophic floods, and (4) small streams of water will rapidly freeze under present climatic conditions. Climatic conditions at the time of formation of the valleys are studied based on the assumption that they were cut by running water.

Carr, M. H.

1984-01-01

402

Exposing a dynamical signature of the freezing transition through the sound propagation gap  

NASA Astrophysics Data System (ADS)

The conventional view of freezing holds that nuclei of the crystal phase form in the metastable fluid through purely stochastic thermal density fluctuations. The possibility of a change in the character of the fluctuations as the freezing point is traversed is beyond the scope of this perspective. Here we show that this perspective may be incomplete by examination of the time autocorrelation function of the longitudinal current, computed by molecular dynamics for the hard-sphere fluid around its freezing point. In the spatial window where sound is overdamped, we identify a change in the long-time decay of the correlation function at the known freezing points of monodisperse and moderately polydisperse systems. The fact that these findings agree with previous experimental studies of colloidal systems in which particle are subject to diffusive dynamics, suggests that the dynamical signature we identify with the freezing transition is a consequence of packing effects alone.

Martinez, V. A.; Zaccarelli, E.; Sanz, E.; Valeriani, C.; van Megen, W.

2014-11-01

403

Freeze concentration of fruit juices.  

PubMed

Concentration of aqueous foods such as fruit juices, milk, beer, wine, coffee, and tea, is a major unit operation in the food industry. Technically feasible processes that are commercially available for the concentration of liquid foods include evaporation, freeze concentration, reverse osmosis, and ultrafiltration. Evaporation is considered to be the most economical and most widely used method of concentration. However, it is not suited for food products with very delicate flavors. Commercial processes for the concentration of such products by membrane separation techniques are not yet available. As compared to the conventional evaporation processes, concentration by freezing is potentially a superior and economic process for aroma-rich liquid foods. In the past, the process, however, was seldom used because of the investment cost and the considerable loss of concentrate in the withdrawn ice, and hence, the quality. Recent technological developments have minimized these two drawbacks associated with the earlier freeze concentration processes. In the coming decade, freeze concentration is seen as a potentially attractive method for the concentration of aroma-rich liquid foods, including fruit juices, coffee, tea, and selected alcoholic beverages. In this article, several aspects of the theoretical considerations behind freeze concentration of fruit juices, the development of new and cheaper designs, and commercially available freeze concentration processes are reviewed. The economics of the process and its application to several other areas of the food industry are also discussed. PMID:6383717

Deshpande, S S; Cheryan, M; Sathe, S K; Salunkhe, D K

1984-01-01

404

Comparative Freezing Patterns in Stems of Cherry and Azalea 1  

PubMed Central

Ice formation in stems, as determined by means of an electrophoretic mobility technique, occurs much more rapidly in azalea than in sour cherry. The difference is more marked in the bark than in the wood. Disrupting the structure of the tissues completely eliminates differences in freezing patterns, although gross anatomical differences do not appear to account for differences in species response. Microscopic examination of frozen stems indicated that little redistribution of water occurred during freezing in azalea, and the tissues were disrupted as these crystals developed. In cherry, on the other hand, water diffused to nucleating centers where crystal growth was not opposed, giving rise to “glaciers.” PMID:16658210

Dennis, Frank G.; Lumis, Glen P.; Olien, C. Robert

1972-01-01

405

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

NASA Astrophysics Data System (ADS)

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

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

406

Assessing point-of-use ultraviolet disinfection for safe water in urban developing communities.  

PubMed

Residents of urban developing communities often have a tap in their home providing treated and sometimes filtered water but its microbial quality cannot be guaranteed. Point-of-use (POU) disinfection systems can provide safe drinking water to the millions who lack access to clean water in urban communities. While many POU systems exist, there are several concerns that can lead to low user acceptability, including low flow rate, taste and odor issues, high cost, recontamination, and ineffectiveness at treating common pathogens. An ultraviolet (UV) POU system was constructed utilizing developing community-appropriate materials and simple construction techniques based around an inexpensive low-wattage, low pressure UV bulb. The system was tested at the bench scale to characterize its hydrodynamic properties and microbial disinfection efficacy. Hydraulically the system most closely resembled a plug flow reactor with minor short-circuiting. The system was challenge tested and validated for a UV fluence of 50 mJ/cm(2) and greater, over varying flow rates and UV transmittances, corresponding to a greater than 4 log reduction of most pathogenic bacteria, viruses, and protozoa of public health concern. This study presents the designed system and testing results to demonstrate the potential architecture of a low-cost, open-source UV system for further prototyping and field-testing. PMID:25473974

Barstow, Christina K; Dotson, Aaron D; Linden, Karl G

2014-12-01

407

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

PubMed Central

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

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

2004-01-01

408

Measurement of water-holding capacity in raw and freeze-dried broiler breast meat with visible and near-infrared spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

The feasibility of using visible/near-infrared spectroscopy (vis/NIR) to segregate broiler breast fillets by water-holding capacity (WHC) was determined. Broiler breast fillets (n = 72) were selected from a commercial deboning line based on visual color assessment. Meat color (L*a*b*), pH (2 and 2...

409

Postmortem aging and freezing and thawing storage enhance ability of early deboned chicken pectoralis major muscle to hold added salt water  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of postdeboning aging and frozen storage on water-holding capacity (WHC) of chicken breast pectoralis major muscle were investigated. Broiler breast muscle was removed from carcasses either early postmortem (2 h) or later postmortem (24 h). Treatments included: no postdeboning aging; 1-...

410

Freezing efficiency of Silver Iodide, ATD and Kaolinite in the contact freezing mode  

NASA Astrophysics Data System (ADS)

The importance of heterogeneous ice nucleation via contact freezing is one of the open questions in the atmospheric science community. In our laboratory, we built the Collision Nucleation CHamber (CLINCH) (Ladino et al. 2011) in which falling cloud droplets can collide with aerosol particles. In this study, contact freezing experiments are conducted to investigate the ice nucleation ability of silver iodide (AgI), kaolinite and Arizona Test Dust (ATD). Silver iodide has been known for its ice nucleation ability since 1940s (Vonnegut 1947) while kaolinite is a clay mineral and known to be a moderate ice nucleus. ATD is a commercial dust sample used by many groups to compare different setups. In CLINCH, size selected aerosol particles collide with water droplets of 80 µm diameter. With the extension in chamber length it is possible to vary the interaction time of ice nuclei and the droplets. Our experiments are performed between -10 to -36 ºC for various concentrations of ice nuclei and different interaction times. The frozen fraction of the droplets is determined using the custom-made depolarization detector IODE (Nicolet et al., 2010). Depolarization of linearly polarized incident laser light is used to determine the ratio of frozen droplets to all droplets. Frozen fractions of the three particle types with different residence times from CLINCH will be presented in this study. The number of collisions between a single droplet and several aerosol particles can be calculated by accounting for the theoretical collision efficiency at the experimental conditions in order to obtain the freezing efficiency (frozen fraction/number of collisions). Nucleation efficiency is compared with other contact freezing studies and with immersion freezing

Nagare, Baban; Marcolli, Claudia; Stetzer, Olaf; Lohmann, Ulrike

2014-05-01

411

Encapsulation and sustained release from biodegradable microcapsules made by emulsification/freeze drying and spray/freeze drying.  

PubMed

Hollow biodegradable poly(DL-lactide) (PLA) particles with porous shell walls were prepared by freeze drying small droplets of PLA solution formed by emulsification or spraying. The hollow freeze-dried particles were dispersed in water, and the resulting aqueous suspensions were exposed to plasticizing solvents, either dichloromethane or compressed carbon dioxide. The plasticizing solvent causes the pores in the shell wall to close, forming microcapsules surrounding an aqueous core. A water soluble drug, procaine hydrochloride, was successfully encapsulated in the microcapsule core. The encapsulation efficiency is affected by the hollow particle morphology, amount of solvent used, solvent exposure time, surfactant, and method of dispersing the freeze-dried particles in water. The encapsulation process is explained in terms of interfacial free energy of the hollow particles and mobility of the plasticized polymer. Controlled release of procaine hydrochloride from the microcapsules into phosphate buffer solution was observed. The microcapsules had a small burst release, with the remainder of encapsulated drug slowly released over 9 days. The novel hollow PLA particles produced by emulsification/freeze drying and spray/freeze drying can potentially be used as vehicles for controlled release. PMID:19423128

Yin, Weisi; Yates, M Z

2009-08-01

412

Is the strategy for cold hardiness in insects determined by their water balance? A study on two closely related families of beetles: Cerambycidae and Chrysomelidae  

Microsoft Academic Search

The strategy for cold-hardiness and water balance features of two closely related families of Coleoptera, Cerambycidae and\\u000a Chrysomelidae, were investigated. Cerambycids were freeze-avoiding with low supercooling points, whereas chrysomelids froze\\u000a at high temperatures and were tolerant to freezing. Hence, the two families have adopted different strategies for cold-hardiness.\\u000a Due to their low trans-cuticular water permeability, the cerambycids have low rates

K. E. Zachariassen; N. G. Li; A. E. Laugsand; E. Kristiansen; S. A. Pedersen

2008-01-01

413

Water Relations assignment. Due Feb 1. 22 points Read the attached popular article from `Natural History' magazine, about sea snakes  

E-print Network

Water Relations assignment. Due Feb 1. 22 points Read the attached popular article from `Natural History' magazine, about sea snakes (Lillywhite, H.B 2009. A Long Drink of Water. Natural History. July to drink? 4. The article gives many examples of adaptations for dealing with osmotic stress in marine

Mitchell, Randall J.

414

1. Coastal waters are often exposed to heavy metals (HM) introduced from point and diffusive sources. Chronic and  

E-print Network

1. Coastal waters are often exposed to heavy metals (HM) introduced from point and diffusive and ALF3-ALF6. Sampling during 04/2004 5. Heavy metals concentration in Amphistegina lobifera is far higher than in sea water. Heavy metals concentration in seawater 4. Most of the dissolved heavy metals

Einat, Aharonov

415

Thermal stresses from large volumetric expansion during freezing of biomaterials.  

PubMed

Thermal stresses were studied in freezing of biomaterials containing significant amounts of water. An apparent specific heat formulation of the energy equation and a viscoelastic model for the mechanics problem were used to analyze the transient axi-symmetric freezing of a long cylinder. Viscoelastic properties were measured in an Instron machine. Results show that, before phase change occurs at any location, both radial and circumferential stresses are tensile and keep increasing until phase change begins. The maximum principal tensile stress during phase change increases with a decrease in boundary temperature (faster cooling). This is consistent with experimentally observed fractures at a lower boundary temperature. Large volumetric expansion during water to ice transformation was shown to be the primary contributor to large stress development. For very rapid freezing, relaxation may not be significant, and an elastic model may be sufficient. PMID:10412455

Shi, X; Datta, A K; Mukherjee, Y

1998-12-01

416

Evaluation of upstream point treatment in flowing water ditches by Aquabac (Bacillus thuringiensis var. israelensis) against Culex quinquefasciatus.  

PubMed

The effectiveness of the upstream point treatment by AQUABAC Biolarvicide (Bacillus thuringiensis var. israelensis, Biological Larvicide Aqueous Suspension) against Culex quinquefasciatus Say in slow-flowing water ditches has been evaluated in St. Augustine Beach, St. Johns County, FL. The upstream point treatment by AQUABAC (liquid) at 0.5 liter/acre provided significant levels of larval control of Cx. quinquefasciatus for all sections of the downstream for 9 days. The upstream point treatment method by larvicides may have potential for use, minimize environmental impacts, and reduce cost and labor in mosquito-control operation for slow-flowing water ditches. PMID:16033130

Xue, Rui-De; Doyle, Melissa A

2005-06-01

417

Semi-Lagrangian integration of a grid-point shallow water model on the sphere  

NASA Technical Reports Server (NTRS)

This paper describes a semi-Lagrangian technique for integrating the equations of motion on the global domain. The technique uses an auxiliary spherical coordinate system at each near-polar gridpoint of the latitude-longitude grid; the auxiliary system is obtained by a rotation such that the new equator passes through the gridpoint in question and the new coordinate directions coincide with those of the original system at that point. The technique was applied to the shallow water equations, incorporating a semiimplicit treatment of the adjustment terms on a C-grid, with two-time levels. A five day integration was successfully carried out for a situation involving strong cross-polar flow. No filtering or diffusion was required to maintain stability over a five day period.

Mcdonald, A.; Bates, J. R.

1988-01-01

418

Effects of a Proprietary Freeze-Dried Water Extract of Eurycoma longifolia (Physta) and Polygonum minus on Sexual Performance and Well-Being in Men: A Randomized, Double-Blind, Placebo-Controlled Study  

PubMed Central

Background. Physta is a proprietary product containing a freeze-dried water extract of Eurycoma longifolia (tongkat ali), which is traditionally used as an energy enhancer and aphrodisiac. We aim to evaluate a 300?mg combination of Physta and Polygonum minus, an antioxidant, with regard to sexual performance and well-being in men. Methods. Men that aged 40–65 years were screened for this 12-week randomized, double-blind, placebo-controlled, parallel-group study. Outcome measures included validated questionnaires that aimed to evaluate erectile function, satisfaction with intervention, sexual intercourse performance, erectile hardness, mood, and overall quality of life. Results. 12 subjects in the active group and 14 in the placebo group completed the study. Significant improvements were noted in scores for the Sexual Intercourse Attempt diary, Erection Hardness Scale, Sexual Health Inventory of Men, and Aging Male Symptom scale (P < 0.05 for all). Three adverse events were reported in the active group and four in the placebo group, none of which were attributed to study product. Laboratory evaluations, including liver and kidney function testing, showed no clinically significant abnormality. Conclusion. Supplementation for twelve weeks with Polygonum minus and the proprietary Eurycoma longifolia extract, Physta, was well tolerated and more effective than placebo in enhancing sexual performance in healthy volunteers. PMID:24550993

Udani, Jay K.; George, Annie A.; Musthapa, Mufiza; Pakdaman, Michael N.; Abas, Azreena

2014-01-01

419

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

420

Benefits and feasibility of effluent trading between point sources: An analysis in support of Clean Water Act reauthorization. Draft report  

Microsoft Academic Search

To prepare for reauthorization of the Clean Water Act, the U.S. Environmental Protection Agency (EPA) commissioned a series of studies of market-based incentive approaches to water pollution abatement. The study addresses one such approach: allowing municipal and industrial point sources to meet water quality goals by trading; i.e., by creating a market to buy and sell allowances to discharge pollutants.

M. Luttner; M. Podar

1992-01-01

421

Including non-point sfources in a water quality trading permit program.  

PubMed

There has been overwhelming interest in addressing water quality issues through the use of economic instruments. Much of this attention has focused on the cost efficiencies offered by Transferable Discharge Permit (TDP) systems. Unfortunately, the attempts to start up permit markets which are able to exploit abatement cost differences between sources have not met with the success expected. Two of the reasons for the lack of success that have been taken up in analysis of these programs have been the problem of transaction costs and in the case of non-point sources (NPS), undefined property rights. The composite market design is a proposal for a TDP system which specifically includes agricultural non-point source (NPS) dischargers and addresses both property rights and transaction cost problems. The composite market consists of three interrelated markets each serving a particular function. When the composite market is mature, the total number of permits issued represents the cap on discharges allowed in the catchment. The structure of the composite market allows this system to be phased in over time with existing institutions and limited demands on financing. PMID:15850173

Collentine, D

2005-01-01

422

The Discontinuity in the First Derivative of the ITS-90 at the Triple Point of Water  

NASA Astrophysics Data System (ADS)

This paper investigates the discontinuity in the derivative [d W/d T 90]TPW of the ITS-90 at the triple point of water, using data for over 40 calibrated standard platinum resistance thermometers (SPRTs). It finds that the discontinuity is in most cases somewhere between 0 and -6 parts in 105, in relative terms, but that the higher numerical values are obtained for `less ideal' SPRTs (those with lower temperature coefficients of resistance), and also for sub-ranges not extending beyond the indium point. These results are investigated vis-à-vis the long-standing observation that the ITS-90 reference values W r(Ga) and W r(Hg) are not completely consistent with data for W(Ga) and W(Hg) for real SPRTs. It discusses what may be done in a future scale to ensure continuity in the first derivative, and it concludes with a comment about the acceptance criteria for SPRTs in the scale.

Rusby, R. L.

2010-09-01

423

Life in a frozen state: adaptive strategies for natural freeze tolerance in amphibians and reptiles.  

PubMed

Winter survival for various species of amphibians and reptiles that hibernate on land depends on freeze tolerance, the ability to survive for long periods of time with up to 65% of total body water as extracellular ice. Freeze tolerance has been described for four species of frogs, one salamander, and hatchlings of the painted turtle. A very limited tolerance also occurs in garter snakes. Studies of freeze tolerance in vertebrates have primarily focused on the wood frog Rana sylvatica and have assessed the regulation of cryoprotectant synthesis, cryoprotectant action in freezing preservation of isolated cells and tissues, metabolism and energetics under the ischemic conditions imposed by freezing, and the role of ice-nucleating agents in blood. The adaptations that preserve life at subzero temperatures for these animals illustrate the principles of vertebrate organ cryopreservation and may have important applications in the development of technology for the freezing preservation of transplantable human organs. PMID:2180324

Storey, K B

1990-03-01

424

Freezing Tolerance of Citrus, Spinach, and Petunia Leaf Tissue 1  

PubMed Central

Seasonal variations in freezing tolerance, water content, water and osmotic potential, and levels of soluble sugars of leaves of field-grown Valencia orange (Citrus sinensis) trees were studied to determine the ability of citrus trees to cold acclimate under natural conditions. Controlled environmental studies of young potted citrus trees, spinach (Spinacia pleracea), and petunia (Petunia hybrids) were carried out to study the water relations during cold acclimation under less variable conditions. During the coolest weeks of the winter, leaf water content and osmotic potential of field-grown trees decreased about 20 to 25%, while soluble sugars increased by 100%. At the same time, freezing tolerance increased from lethal temperature for 50% (LT50) of ?2.8 to ?3.8°C. In contrast, citrus leaves cold acclimated at a constant 10°C in growth chambers were freezing tolerant to about ?6°C. The calculated freezing induced cellular dehydration at the LT50 remained relatively constant for field-grown leaves throughout the year, but increased for leaves of plants cold acclimated at 10°C in a controlled environment. Spinach leaves cold acclimated at 5°C tolerated increased cellular dehydration compared to nonacclimated leaves. Cold acclimated petunia leaves increased in freezing tolerance by decreasing osmotic potential, but had no capacity to change cellular dehydration sensitivity. The result suggest that two cold acclimation mechanisms are involved in both citrus and spinach leaves and only one in petunia leaves. The common mechanism in all three species tested was a minor increase in tolerance (about ?1°C) resulting from low temperature induced osmotic adjustment, and the second in citrus and spinach was a noncolligative mechanism that increased the cellular resistance to freeze hydration. PMID:16666563

Yelenosky, George; Guy, Charles L.

1989-01-01

425

Matrix Cracking and Delaminations in Orthotropic Laminates Subjected to Freeze-Thaw: Model Development  

Microsoft Academic Search

SUMMARY With the increasing use of fibre composites in applications such as cryogenic liquid hydrogen tanks and repair\\/retrofitting of bridges, the diffusion and freezing of moisture to form ice is an issue of growing importance. The volumetric expansion of water when it freezes to form ice results in stress concentrations at the inclusion tip that may synergistically interact with the

Samit Roy; G. H. Nie; R. Karedla; L. Dharani

2002-01-01

426

Stabilization of Lipid Bilayer Vesicles by Sucrose during Freezing  

NASA Astrophysics Data System (ADS)

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 structure. When frozen in sucrose solution, the lipid also was compressed between the ice crystals but remained in the form of vesicles. The fractional amount of lipid remaining as SUV after freezing was found to increase significantly only at sucrose/lipid molar ratios above 0.4. Eu3+ displaced sucrose from the lipid by competitive binding. During freezing in the absence of sucrose, the vesicles became transiently permeable to ions. ESR studies showed that fusion of vesicles in the absence of sucrose is far more extensive when they are frozen while above their phase-transition temperature (tc) than when frozen while below their tc. It is concluded that the extent of membrane disruption depends on the membrane mobility at the moment of freezing and that sucrose exerts its protective effect by binding to the membrane interface and/or by affecting the water structure.

Strauss, G.; Hauser, H.

1986-04-01

427

Glass Transitions and State Diagram for Freeze-dried Pineapple  

Microsoft Academic Search

Glass transition temperature of freeze-dried pineapple conditioned by adsorption at various water activities at 25 °C was determined by differential scanning calorimetry (DSC). High moisture content samples corresponding to water activities higher than 0.9, obtained by liquid water addition, were also analysed. The DSC traces showed a well-visible shift in baseline at the glass transition temperature (Tg). Besides, no ice

V. R. N. Telis; P. J. A. Sobral

2001-01-01

428

Water quality along a river continuum subject to point and diffuse sources  

NASA Astrophysics Data System (ADS)

SummaryThe water quality along the River Kennet, in the Thames basin of southern England, was examined in terms of the influence of point- and diffuse-nutrient inputs. The river is supplied mainly from a Cretaceous Chalk aquifer and hence the waters are of a calcium bicarbonate type. The nitrate largely comes from agricultural sources, with concentrations decreasing downstream due to plant uptake and probable denitrification. In contrast, soluble reactive phosphorus (SRP) is largely associated with sewage inputs and concentrations increase downstream in line with effluents from major towns such as Newbury and Reading. Adjacent to the river in the lower half of the catchment is the Kennet and Avon Canal and the two are in places hydrologically connected. The canal inputs may influence calcium carbonate (calcite) precipitation and increase suspended sediment and particulate phosphorus concentrations in the river. Monitoring upstream and downstream of Marlborough sewage treatment works (STW) showed that SRP concentrations in the effluent were highly variable due to variable efficiency of P stripping and still sufficiently concentrated to dominate downstream river SRP with potential impacts on stream ecology. Biological recovery in this river following P stripping at STWs is complex and controlling those spikes in SRP that are above a threshold of 100 ?g l -1 may be a critical requirement. More stringent effluent targets than are currently recommended may be needed (less than 800 ?g RP l -1) to achieve good ecological status in this river depending on SRP concentrations upstream.

Neal, Colin; Jarvie, Helen P.; Love, Alison; Neal, Margaret; Wickham, Heather; Harman, Sarah

2008-02-01

429

Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view  

NASA Astrophysics Data System (ADS)

By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

2013-11-01

430

Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view.  

PubMed

By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given. PMID:24289362

Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

2013-11-28

431

Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view  

SciTech Connect

By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

Chen, Yu-Chun; Tang, Ping-Han [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China)] [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); Wu, Ten-Ming, E-mail: tmw@faculty.nctu.edu.tw [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China) [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); National Center for Theoretical Sciences, Hsinchu 300, Taiwan (China)

2013-11-28

432

Isotopic Effects on the Temperature of the Triple Point of Water  

NASA Astrophysics Data System (ADS)

An investigation into the effects of isotopic composition on the triple point temperature of water has been carried out at the National Institute of Metrology (NIM), China, since redefinition of the kelvin with respect to Vienna Standard Mean Ocean Water (V-SMOW) was officially proposed by the Consultative Committee for Thermometry (CCT) in 2005. In this paper, a comparison of four cells with isotopic analyses and relevant results corrected for isotopic composition, employing the isotope correction algorithm recommended by the CCT, is described. The results indicate that, after application of the corrections, the maximum temperature difference between the cells drops from 0.10 mK to 0.02 mK and that these cells are in good agreement within 0.02 mK. Also, temperature deviations arising from isotopic variations fall in the range from -55.9 ?K to + 40.7 ?K. We consider that the distillation temperature and degassing time of the production procedure lead to isotopic variations.

Yan, X. K.; Zhang, J. T.; Wang, Y. L.; Ma, C. F.; Duan, Y. N.

2008-02-01

433

Measuring Total Column Water Vapor by Pointing an Infrared Thermometer at the Sky  

NASA Technical Reports Server (NTRS)

A 2-year study affirms that the temperature (Tz) indicated by an inexpensive ($20 to $60) IR thermometer pointed at the cloud-free zenith sky provides an approximate indication of the total column water vapor (precipitable water or PW). PW was measured by a MICROTOPS II sun photometer. The coefficient of correlation (r2) of the PW and Tz was 0.90, and the rms difference was 3.2 mm. A comparison of the Tz data with the PW provided by a GPS site 31 km NNE yielded an r2 of 0.79, and an rms difference of 5.8 mm. An expanded study compared Tz from eight IR thermometers with PW at various times during the day and night from 17 May to 18 October 2010, mainly at the Texas site and 10 days at Hawaii's Mauna Loa Observatory (MLO). The best results of this comparison were provided by two IR thermometers models that yielded an r2 of 0.96 and an rms difference with the PW of 2.7 mm. The results of both the ongoing 2-year study and the 5-month instrument comparison show that IR thermometers can measure PW with an accuracy (rms difference/mean PW) approaching 10%, the accuracy typically ascribed to sun photometers.

Mims, Forrest M., III; Chambers, Lin H.; Brooks, David R.

2011-01-01

434

An Experimental Investigation of the Long-Term Stability of Triple-Point-of-Water Cells  

NASA Astrophysics Data System (ADS)

Contamination of triple-point-of-water (TPW) cells by the chemical components of the borosilicate glass that contains the water is now widely recognized as the principal contributor to long-term drift of the cell temperature. To add to the available experimental data, a comparison of 24 TPW cells of various ages (from 10 years to 59 years), manufacturers (NRC, Jarrett, Isotech), and materials (borosilicate glass and fused quartz) was undertaken in 2013. Twelve cells from this group were compared to one another in 1997. By comparing the current inter-cell temperature differences to those determined 16 years earlier, it was found that some cells have remained stable, others have become colder (as might be expected from ongoing dissolution of the glass), and one or two show an apparent increase in temperature that seems anomalous. Also included among the 24 cells are five cells of borosilicate glass and five of fused quartz that were purchased 10 years ago. By comparing the relative temperature differences among this group of borosilcate and fused-quartz-encapsulated cells to the values obtained when they were last compared 6 years ago, it was found that the average temperature of the borosilcate group of cells decreases by , in reasonable agreement with an average drift of suggested 12 years ago. It was concluded that fused quartz is the superior container for TPW cells.

Hill, K. D.

2014-04-01

435

PFG-NMR study for evaluating freezing damage to onion tissue.  

PubMed

We assessed the damage to onion tissue due to freeze-thawing as the water permeability determined by using PFG-NMR and light microscopy. The water diffusion in fresh onion tissue was restricted due to cellular barriers, and the estimated water permeability was 6.99 x 10(-6)m/s. The water diffusion became considerably less restricted after freeze-thawing; the convergent value for the restricted diffusion coefficient increased and the water permeability significantly increased to 2.85 x 10(-5) m/s. While NMR could detect a distinct change in the diffusion behavior of water molecules in freeze-thawed tissue, light microscopy revealed no significant tissue damage. These results suggest that freeze-thawing damaged the vegetable tissues primarily through destruction of the cell membrane rather than the cell wall. PMID:19502742

Ando, Hiroko; Fukuoka, Mika; Miyawaki, Osato; Watanabe, Manabu; Suzuki, Toru

2009-06-01

436

Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [Lower Rio Grande Valley Test Site: Weslaco, Texas; Falco Reservoir and the Gulf of Mexico  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. HCMM day/night coverage 12 hours apart cannot be obtained at 26 deg N latitude; nor have any pairs 36 hours apart been obtained. A day-IR scene and a night scene for two different dates were analyzed. A profile across the test site for the same latitude shows that the two profiles are near mirror images of each other over land surfaces and that the temperature of two large water bodies, Falcon Reservoir and the Gulf of Mexico, are nearly identical on two dates. During the time interval between overpasses, the vegetative cover remained static due to winter dormancy. The data suggest that day/night temperature differences measured weeks apart may yield meaningful information about the contrast between daytime maximum and nighttime minimum temperatures for a given site.

Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (principal investigators)

1980-01-01

437

Freeze-in through portals  

NASA Astrophysics Data System (ADS)

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

Blennow, Mattias; Fernandez-Martínez, Enrique; Zaldívar, Bryan

2014-01-01

438

Freezing and thawing porous media: experimental study with a dielectric capacitive method  

NASA Astrophysics Data System (ADS)

A capacitive sensor-based apparatus has been used to study the ice/water phase change in consolidated porous media subjected to freezing and thawing. This technique relies on the dielectric properties of water, ice, air, and the mineral substrate in the radio-frequency range. It gives directly the freezing and thawing temperature depressions and indirectly provides an estimation of pore size distribution through the Gibbs-Thomson relation. It also holds good promise for evaluating the amount of liquid water in frozen porous media by combining drying and freezing tests. To cite this article: T. Fen-Chong, A. Fabbri, C. R. Mecanique 333 (2005).

Fen-Chong, Teddy; Fabbri, Antonin

2005-05-01

439

California State Waters Map Series: offshore of Coal Oil Point, California  

USGS Publications Warehouse

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Coal Oil Point map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 2.0 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The cities of Goleta and Isla Vista, the main population centers in the map area, are in the western part of a contiguous urban area that extends eastward through Santa Barbara to Carpinteria. This urban area is on the south flank of the east-west-trending Santa Ynez Mountains, on coalescing alluvial fans and uplifted marine terraces underlain by folded and faulted Miocene bedrock. In the map area, the relatively low-relief, elevated coastal bajada narrows from about 2.5 km wide in the east to less than 500 m wide in the west. Several beaches line the actively utilized coastal zone, including Isla Vista County Park beach, Coal Oil Point Reserve, and Goleta Beach County Park. The beaches are subject to erosion each winter during storm-wave attack, and then they undergo gradual recovery or accretion during the more gentle wave climate of the late spring, summer, and fall months. The Offshore of Coal Oil Point map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Longshore drift rates have been reported to range from about 160,000 to 800,000 tons/yr, averaging 400,000 tons/yr. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) Las Llagas Canyon, Gato Canyon, Las Varas Canyon, Dos Pueblos Canyon, Eagle Canyon, Tecolote Canyon, Winchester Canyon, Ellwood Canyon, Glen Annie Canyon, and San Jose Creek. The Santa Ynez and Santa Maria Rivers, the mouths of which are about 100 to 140 km northwest of the map area, are not significant sediment sources because Point Conception and Point Arguello provide obstacles to downcoast sediment transport and also because much of their sediment load is trapped in dams. The Ventura and Santa Clara Rivers, the mouths of which are about 45 to 55 km southeast of the map area, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.8° to 1.0°) so that water depths at the shelf break, roughly coincident with the California’s State Waters limit, are about 90 m. This part

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Dieter, Bryan E.; Conrad, James E.; Lorenson, Thomas D.; Krigsman, Lisa M.; Greene, H. Gary; Endris, Charles A.; Seitz, Gordon G.; Finlayson, David P.; Sliter, Ray W.; Wong, Florence L.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Leifer, Ira; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Hostettler, Frances D.; Peters, Kenneth E.; Kvenvolden, Keith A.; Rosenbauer, Robert J.; Fong, Grace

2014-01-01

440

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

A section of a strawberry field that was destroyed by a sinkhole and filled in, as is done with many sinkholes if possible. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows as farmers pump...

441

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

Sinkholes affect structures as well as many types of supporting infrastructure such as buried utilities lines seen here. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting lows ...

442

Sinkholes in West-central Florida, Freeze Event of 2010  

USGS Multimedia Gallery

Cracks shown here in the exterior and supporting structures of this home are indicative of subsidence damage associated with sinkhole activity. More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Ground water levels dropped to record-setting l...

443

Freezing effect on shear strength of clayey soils  

Microsoft Academic Search

The design and construction of earth structures influenced seasonally by subzero temperatures requires the determination of mechanical properties of the construction materials under appropriate thermal conditions. Water saturated materials exhibit a zone of partially frozen soil at the frozen-unfrozen soil interface. To define the critical failure surface and governing shear strength in this zone, the effects of partial freezing on

K. A. Czurda; M. Hohmann

1997-01-01

444

Observations of ice nucleation by ambient aerosol in the homogeneous freezing regime  

NASA Astrophysics Data System (ADS)

We measured the freezing activation curves for ambient particles as a function of relative humidity with respect to water over the temperature range of -40° to -50°C using a continuous flow diffusion chamber, and compared the observations with those for ammonium sulfate particles and predictions from a parametric representation of homogeneous freezing of solution particles as a function of water activity and temperature. Since it has been proposed that the rate of homogeneous freezing depends on solution water activity, we made separate measurements of the hygroscopicity ($\\kappa$) of the ambient aerosol. Observed $\\kappa$ ranged from 0.1 to 0.2, lower than that of ammonium sulfate (0.6) and representative of a continental aerosol. As predicted for this difference in $\\kappa$, there was no significant difference between the homogeneous freezing conditions of size-selected ammonium sulfate and the apparent homogeneous freezing conditions of same-sized ambient aerosol. Further, the parameterization predicted freezing fraction-relative humidity relationships for non size-selected ambient aerosol that differed by only 0.5 to 1.5% relative humidity from observed relations at the tested temperatures, well within experimental uncertainty. Our findings confirm that the tested ambient aerosols, with hygroscopicities typical of continental regions, freeze homogeneously as expected based on present understanding for single component solution drops in the laboratory. Results also confirm that freezing is more sensitive to particle size than to composition, for particles containing at least a few percent by volume of hygroscopic species.

Richardson, Mathews S.; DeMott, Paul J.; Kreidenweis, Sonia M.; Petters, Markus D.; Carrico, Christian M.

2010-02-01