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1

THE FREEZING POINT DEPRESSION OF MAMMALIAN TISSUES AFTER SUDDEN HEATING IN BOILING DISTILLED WATER  

Microsoft Academic Search

The calculated freezing point depression of freshly excised boiled mammalian tissue is approximately the same as that of plasma. The boiling procedure was chosen to eliminate the influence of metabolism on the level of the freezing point depression. Problems created by the boiling, such as equilibrium between tissue and diluent, change in activity coefficient by dilution, and loss of CO~

J. W. Th. Appelboom; WILLIAM A. BRODSK; WILLIAM S. TUTTLE; ISRAEL DIAMOND

1958-01-01

2

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...

3

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

Microsoft Academic Search

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

N. Genin; F. Rene; G. Corrieu

1996-01-01

4

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

5

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

6

When the Melting and Freezing Points are not the Same  

Microsoft Academic Search

Almost every solid has a melting point, and almost every liquid has a freezing point. These two points are one and the same, just viewed from different perspectives: ice melts at zero degrees Celsius--the highest temperature at which it can be a stable solid--whereas water freezes at zero degrees C--the lowest temperature at which it can be a stable liquid.

R. Stephen Berry

1990-01-01

7

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

8

Measurement of Freezing Point Depression of Selected Food Solutions  

NASA Astrophysics Data System (ADS)

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

Murata, Satoshi; Tanaka, Fumihiko; Matsuoka, Takahisa

9

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

10

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

11

Structurally Caused Freezing Point Depression of Biological Tissues  

PubMed Central

When investigating the freezing behaviour (by thermal analysis) of the glycerol-extracted adductor muscle of Mytilus edulis it was observed that the temperature of ice formation in the muscular tissue was up to 1.5°C lower than the freezing point of the embedding liquid, a 0.25 N KCl solution with pH = 4.9 with which the tissue had been equilibrated prior to the freezing experiment. A smaller freezing point depression was observed if the pH values of the embedding 0.25 N KCl solution were above or below pH = 4.9. Reasoning from results obtained previously in analogous experiments with artificial gels, the anomalous freezing depression is explained by the impossibility of growing at the normal freezing temperature regular macroscopic crystals inside the gel, due to the presence of the gel network. The freezing temperature is here determined by the size of the microprisms penetrating the meshes of the network at the lowered freezing temperature. This process leads finally to an ice block of more or less regular structure in which the filaments are embedded. Prerequisite for this hindrance of ideal ice growth is a sufficient tensile strength of the filamental network. The existence of structurally caused freezing point depression in biological tissue is likely to invalidate many conclusions reported in the literature, in which hypertonicity was deduced from cryoscopic data. PMID:13971682

Bloch, Rene; Walters, D. H.; Kuhn, Werner

1963-01-01

12

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

13

The Freezing Point Depression Law in Physical Chemistry.  

ERIC Educational Resources Information Center

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

Franzen, Hugo F.

1988-01-01

14

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

NASA Astrophysics Data System (ADS)

Soil freezing point is the highest temperature at which ice can be presented in the system and soil can be referred to as frozen. The freezing temperature of soil is an important parameter for solving many practical problems in civil engineering, such as evaluation of soil freezing depth, prediction of soil heaving, force of soil suction, etc. However, as the freezing temperature is always affected by many factors like soil particle size, mineral composition, water content and the external pressure endured by soils, to measure soil freezing point is a rather difficult task until now, not to mention the soil suffering higher pressure. But recently, with the artificial freezing technology widely used in the excavation of deep underground space, the frozen wall thickness is a key factor to impact the security and stability of deep frozen wall. To determine the freeze wall thickness, the location of the freezing front must be determined firstly, which will deal with the determination of the soil freezing temperature. So how to measure the freezing temperature of soil suffering higher pressure is an important problem to be solved. This paper will introduce an equipment which was developed lately by State Key Laboratory of Frozen Soil Engineering to measure the freezing-point of soils under higher pressure. The equipment is consisted of cooling and keeping temperature system, temperature sensor and data collection system. By cooling and keeping temperature system, not only can we make the higher pressure soil sample's temperature drop to a discretionary minus temperature, but also keep it and reduce the heat exchange of soil sample with the outside. The temperature sensor is the key part to our measurement, which is featured by high precision and high sensitivity, what is more important is that the temperature sensor can work in a higher pressure condition. Moreover, the major benefit of this equipment is that the soil specimen's loads can be loaded by any microcomputer control electron universal testing machines. All of above mentioned advantages of this equipment ensures one to catch up the moment soil turns from the thawed state into ice and enable one to determine the freezing point experimentally by recording the temperature-time history (cooling curve) at particular points within the sample used for analysis. Therefore, this equipment has excellent characteristics such as compact construction, convenient operation, high reliability and the measuring accuracy. The authors would like to thank the following agents for their financial supports: the National Natural Science Foundation (No.41071048),Hundred Talent Young Scientists program of the Chinese Academy of Sciences granted to Dr. Zhi Wen.

Wang, Dayan; Guan, Hui; Wen, Zhi; Ma, Wei

2014-05-01

15

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

16

The Solubility-Freezing Point Relationships of Water Solutions Saturated with Respect to Sucrose and Dextrose in Relation to the Storage of Sherbet and Water Ice  

Microsoft Academic Search

if the sherbet was held at a temperature higher than the euteetie tempera- ture of the system cane-s~gar-water, which he determined to be as approxi- mately- 12 ° C. Dahlberg (2) showed this independently, and also showed that sugar separation could be prevented at even lower temperatures if dextrose or corn sugar was used in place of part of the

Alan Leighton; Abraham Leviton

1935-01-01

17

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

18

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

19

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

20

Modeling solute segregation during freezing of peatland waters  

Microsoft Academic Search

Freezing of the shallow water in a peatland causes the downward movement of solutes. Field and laboratory data demonstrate that a considerable portion of the solutes are driven into the top soil from the overlying water by freezing. Such solute redistribution phenomena in peatlands are of interest for establishing the geochronology of deposits and determining the nature of pollutant burial.

Robert H. Kadlec; Xiang-Ming Li; Gerald B. Cotten

1988-01-01

21

Water Relations of Pachysandra Leaves during Freezing and Thawing 1  

PubMed Central

The evergreen herb Pachysandra terminalis becomes moderately frost-hardy in winter. The water relations of its frost-hardy leaves were studied during a freeze-thaw cycle. Leaf water potentials, measured by psychrometry at subfreezing temperatures, were identical with those of ice, indicating equilibrium freezing. Microscopic observations showed extracellular freezing of tissue water. As evidenced by thermal analysis, the freezing process starts with the crystallization of a minor volume which was identified as apoplasmic water. The following long-lasting exotherm indicated slow export of water from the protoplasts driven by extracellular crystallization. In partially frozen leaves, the fractions of liquid water were measured at several subfreezing temperatures by nuclear magnetic resonance spectroscopy. They were consistently greater than those calculated from the osmotic potentials of cellular fluid, and the differences increased with decreasing temperature. About 50% of the differences could be abolished by freeze-killing of the leaf and was thus ascribed to the effect of a (negative) pressure reinforcing the osmotic potential. The persistent part of the differences may have reflected a matric component. At ?7°C, the absolute values of both potentials were ?1.7 megapascals each. The water relations of Pachysandra leaves clearly indicate nonideal equilibrium freezing where negative pressures and matric potentials contribute to the leaf water potential and thus alleviate freeze-dehydration of the tissue. ImagesFigure 1Figure 5 PMID:16668501

Zhu, Jian-Jun; Beck, Erwin

1991-01-01

22

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

23

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

PubMed

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

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

2010-03-01

24

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 the cavity to be rinsed. Expansion of water in the phase transition to ice can lift particles from particles and finally the rinsing turns into regular high pressure rinsing. INTRODUCTION High-pressure water

25

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

26

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

27

Units of freezing of deep supercooled water in woody xylem.  

PubMed

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

Hong, S G; Sucoff, E

1980-07-01

28

Time dependent freezing of water under dynamic compression.  

SciTech Connect

Using shock wave reverberation experiments, water samples were quasi-isentropically compressed between silica and sapphire plates to peak pressures of 1-5 GPa on nanosecond time scales. Real time optical transmission measurements were used to examine changes in the compressed samples. Although the ice VII phase is thermodynamically favored above 2 GPa, the liquid state was initially preserved and subsequent freezing occurred over hundreds of nanoseconds only for the silica cells. Images detailing the formation and growth of the solid phase were obtained. These results provide unambiguous evidence of bulk water freezing on such short time scales.

Dolan, Daniel H., III (Washington State University, Pullman, WA)

2003-07-01

29

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 describes the phenomenon of a sample of hot water freezing faster than a specimen of cold water to explain why hot water can freeze faster than cold water when all other conditions are identical. We

Suzuki, Masatsugu

30

Phenomena of Pipe Fracture by Freezing Water in Air Conditioner  

NASA Astrophysics Data System (ADS)

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

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

31

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

32

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

33

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

34

Thermodynamic temperature measurements of silver freezing point and HTFPs  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

35

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

36

The frozen soul: sin and forgiveness in Miura Ayako's Freezing Point  

Microsoft Academic Search

Miura Ayako (1922–99) rose from obscurity to literary stardom on the basis of her first novel, Hy?ten, published serially in 1964–5, and became in the process not only one of Japan's best-selling novelists but also one of its leading Christian voices. Hy?ten (Freezing point), one of the best-known and most widely read novels of the past few decades, follows the

Philip Gabriel

2005-01-01

37

The Nonparametric Analysis of Point Process Data: The Freezing History of Lake Konstanz.  

NASA Astrophysics Data System (ADS)

Climate records sometimes have the form of point processes (i.e., observations of the times of occurrence of a specified type of event). A central problem in the analysis of point process data is the estimation of the rate function, defined as the expected number of events occurring in a time interval of unit length. This paper describes some simple nonparametric methods for estimating the rate function and for assessing its statistical significance. The methods are applied to the freezing history of Lake Konstanz.

Solow, Andrew R.

1991-01-01

38

Freezing of glycerol-water mixtures under pressure.  

PubMed

We investigated freezing of pure glycerol as well as glycerol-water (GW) mixtures with 3:1 and 3:2 volume fractions as a function of pressure in the 0-10 GPa range by ruby fluorescence spectroscopy and neutron scattering. We find that the glass transition pressure increases from 5.5 GPa for pure glycerol to 6.5 GPa for the 3:1 GW mixture, with unusually small pressure gradients above. For higher water concentrations close to 3:2, phase separation occurs above 2 GPa where most of the water is expelled in the form of ice VII. The results suggest that glycerol is able to effectively hydrogen bond not more than ?2.5 H(2)O molecules per glycerol, which seems to support conclusions from molecular dynamics simulations. The data indicate that these fluids could become important as pressure transmitting media for neutron scattering in the 0-7 GPa range, including at low temperatures. PMID:22689331

Klotz, S; Takemura, K; Strässle, Th; Hansen, Th

2012-08-15

39

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

40

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

41

Early Mars was wet but not warm: Erosion, fluvial features, liquid water habitats, and life below freezing  

NASA Technical Reports Server (NTRS)

There is considerable evidence that Mars had liquid water early in its history and possibly at recurrent interval. It has generally been assumed that this implied that the climate was warmer as a result of a thicker CO2 atmosphere than at the present. However, recent models suggest that Mars may have had a thick atmosphere but may not have experienced mean annual temperatures above freezing. In this paper we report on models of liquid water formation and maintenance under temperatures well below freezing. Our studies are based on work in the north and south polar regions of Earth. Our results suggest that early Mars did have a thick atmosphere but precipitation and hence erosion was rare. Transient liquid water, formed under temperature extremes and maintained under thick ice covers, could account for the observed fluvial features. The main difference between the present climate and the early climate was that the total surface pressure was well above the triple point of water.

Mckay, C. P.; Davis, W. L.

1993-01-01

42

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

43

Water in a Polymeric Electrolyte Membrane: Sorption/Desorption and Freezing phenomena  

E-print Network

Nafion is a perfluorosulfonated polymer, widely used in Proton Exchange Membrane Fuel Cells. This polymer adopts a complex structural organisation resulting from the microsegregation between hydrophobic backbones and hydrophilic sulfonic acid groups. Upon hydration appear water-filled channels and cavities, in which are released the acidic protons to form a solution of hydronium ions in water embedded in the polymer matrix. Below 273 K, a phenomenon of water sorption/desorption occurs, whose origin is still an open question. Performing neutron diffraction, we monitored the quantity of ice formed during the sorption/desorption as a function of temperature down to 180 K. Upon cooling, we observe that ice forms outside of the membrane and crystallises in the hexagonal Ih form. Simultaneously, the membrane shrinks and dehydrate, leading to an increase of the hydronium ions concentration inside the matrix. Reversibly, the ice melts and the membrane re-hydrate upon heating. A model of solution, whose freezing point varies with the hydronium concentration, is proposed to calculate the quantity of ice formed as a function of temperature. The quantitative agreement between the model and experimental data explains the smooth and reversible behavior observed during the sorption or desorption of water, pointing out the origin of the phenomena. The proposed picture reconciles both confinement and entropic effects. Other examples of water filled electrolyte nano-structures are eventually discussed, in the context of clarifying the conditions for water transport at low temperature.

Marie Plazanet; Francesco Sacchetti; Caterina Petrillo; Bruno Deme; Paolo Bartolini; Renato Torre

2013-05-02

44

Absolute Spectral Radiometric Determination of the Thermodynamic Temperatures of the Melting\\/Freezing Points of Gold, Silver and Aluminium  

Microsoft Academic Search

Narrow band filter radiometers have been used to measure the spectral radiance of black bodies held at the melting\\/freezing points of aluminium, silver and gold with an accuracy of 0,04%. Descriptions are given of the optical components and the techniques used for their characterization. As the measurements are absolute, the thermodynamic temperatures of these points can be calculated directly from

N. P. Fox; J. E. Martin; D. H. Nettleton

1991-01-01

45

Spray freeze-dried porous microparticles of a poorly water-soluble drug for respiratory delivery.  

PubMed

Particles of poorly water-soluble drugs were prepared to develop a dry powder inhaler (DPI). Spray freeze-drying (SFD) technique using a four-fluid nozzle (4N), which has been developed by authors, was applied in this research. Ciclosporin and mannitol were used as a poorly water-soluble model drug and a dissolution-enhanced carrier, respectively. The organic solution of ciclosporin and aqueous solution of mannitol were separately and simultaneously atomized through the 4N, and the two solutions were collided with each other at the tip of the nozzle edge. The spray mists were immediately frozen in liquid nitrogen to form a suspension. Then, the iced droplets were freeze-dried to prepare the composite particles of the drug and carrier. tert-Butyl alcohol (t-BuOH) was used as the organic spray solvent due to its relatively high freezing point. The resultant composite particles with varying drug content were characterized depending on their morphological and physicochemical properties. The particles contained amorphous ciclosporin and ?-crystalline mannitol. The characteristic porous structure of SFD particles potentially contributed to their good aerodynamic performance. A series of particles with a similar size distribution and different drug content revealed that the incorporation of mannitol successfully improved the cohesive behavior of ciclosporin, leading to enhanced aerosol dispersion. The dissolution test method using low-volume medium was newly established to simulate the release process from particles deposited on the surface of the bronchus and pulmonary mucosa. The composite with hydrophilic mannitol dramatically improved the in vitro dissolution behavior of ciclosporin in combination with the porous structure of SFD particles. PMID:22790820

Niwa, Toshiyuki; Mizutani, Daisuke; Danjo, Kazumi

2012-01-01

46

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

Microsoft Academic Search

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

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

2003-01-01

47

Freeze-dried plasma at the point of injury: from concept to doctrine.  

PubMed

While early plasma transfusion for the treatment of patients with ongoing major hemorrhage is widely accepted as part of the standard of care in the hospital setting, logistic constraints have limited its use in the out-of-hospital setting. Freeze-dried plasma (FDP), which can be stored at ambient temperatures, enables early treatment in the out-of-hospital setting. Point-of-injury plasma transfusion entails several significant advantages over currently used resuscitation fluids, including the avoidance of dilutional coagulopathy, by minimizing the need for crystalloid infusion, beneficial effects on endothelial function, physiological pH level, and better maintenance of intravascular volume compared with crystalloid-based solutions. The Israel Defense Forces Medical Corps policy is that plasma is the resuscitation fluid of choice for selected, severely wounded patients and has thus included FDP as part of its armamentarium for use at the point of injury by advanced life savers, across the entire military. We describe the clinical rationale behind the use of FDP at the point-of-injury, the drafting of the administration protocol now being used by Israel Defense Forces advanced life support providers, the process of procurement and distribution, and preliminary data describing the first casualties treated with FDP at the point of injury. It is our hope that others will be able to learn from our experience, thus improving trauma casualty care around the world. PMID:24089000

Glassberg, Elon; Nadler, Roy; Gendler, Sami; Abramovich, Amir; Spinella, Philip C; Gerhardt, Robert T; Holcomb, John B; Kreiss, Yitshak

2013-12-01

48

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

PubMed

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

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

2010-02-01

49

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

50

Droplet freezing experiments in stearic acid-water emulsions, role of the droplet-medium interface  

SciTech Connect

Droplets of stearic acid emulsions in water, stabilized with cationic or anionic emulsifiers, undergoing freezing-melting cycles with constant temperature scanning rate, freeze as monocrystals and independently from one another, even when visible clustering takes place. The study of the nucleation kinetics by differential scanning calorimetry shows that nucleation threshold (critical undercooling) depends on the nature of the emulsifier, adsorbed at the droplet-medium interface. 30 references.

Cordiez, J.P.; Grange, G.; Mutaftschiev, B.

1982-02-01

51

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

PubMed

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

Lee, R E; Hankison, S J

2003-04-01

52

Glycine betaine involvement in freezing tolerance and water stress in Arabidopsis thaliana.  

PubMed

Levels of endogenous glycine betaine in the leaves were measured in response to cold acclimation, water stress and exogenous ABA application in Arabidopsis thaliana. The endogenous glycine betaine level in the leaves increased sharply during cold acclimation treatment as plants gained freezing tolerance. When glycine betaine (10 mM) was applied exogenously to the plants as a foliar spray, the freezing tolerance increased from -3.1 to -4.5 degrees C. In addition, when ABA (1 mM) was applied exogenously, the endogenous glycine betaine level and the freezing tolerance in the leaves increased. However, the increase in the leaf glycine betaine level induced by ABA was only about half of that by the cold acclimation treatment. Furthermore, when plants were subjected to water stress (leaf water potential of approximately -1.6 MPa), the endogenous leaf glycine betaine level increased by about 18-fold over that in the control plants. Water stress lead to significant increase in the freezing tolerance, which was slightly less than that induced by the cold acclimation treatment. The results suggest that glycine betaine is involved in the induction of freezing tolerance in response to cold acclimation, ABA, and water stress in Arabidopsis plants. PMID:11378169

Xing, W; Rajashekar, C B.

2001-08-01

53

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

54

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

E-print Network

Can Propagation of Gas Bubbles Lead to Detached Solidification? Experiments on Freezing of Water solidify water upward, in the hope that detached solidification would evolve from gas bubbles forming caused gas bubbles or tubes to form only at the ampoule wall, and not in the interior. Gas tubes were

Regel, Liya L.

55

Detection of cavitation events upon freezing and thawing of water in stems using ultrasound techniques  

E-print Network

water stress or freezing during the previous months; xylem water potential, measured by pressure chamber of 5°C per hour. To measure the acoustic emission rate, a Bruel and Kjaer 8312 broad band sensor loss and then with ultra- sound gel to improve acoustic transmission. To avoid heating effects

Paris-Sud XI, Université de

56

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

57

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

Microsoft Academic Search

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

A. M. Elmonsef Omar; Yrjö H. Roos

2007-01-01

58

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

59

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

60

Freezing heat transfer in water-saturated porous media in a vertical rectangular vessel  

Microsoft Academic Search

Numerical and experimental study is performed for the freezing of water-saturated porous media in a vertical rectangular vessel. The governing equations are solved by using a variable transformation and employing a finite difference scheme. The SOR method is utilized to solve numerically the equations. Different size and types of spherical beads are used as the porous media. The temperature of

A. Sasaki; S. Aiba; S. Fukusako

1992-01-01

61

Freeze-Fracture Imaging of Ordered Phases of Tobacco Mosaic Virus in Water  

Microsoft Academic Search

Aqueous solutions of Tobacco Mosaic Virus are ideal systems for visualizing “molecular” distributions in nematic and crystalline phases by freeze-fracture electron microscopy. Nematic phases of TMV in water are highly oriented with measured order parameters of 0.93. Twist deformations appear to be most common in the micrographs, confirming experimental and theoretical evidence that the twist elastic constant is smaller than

Joseph A. N. Zasadzinski; Michael J. Sammon; Robert B. Meyer; M. Cahoon; D. L. D. Caspar

1986-01-01

62

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.)

63

A Photographic Study of Freezing of Water Droplets Falling Freely in Air  

NASA Technical Reports Server (NTRS)

A photographic technique for investigating water droplets of diameter less than 200 microns falling freely in air at temperatures between 0 C and -50 C has been devised and used to determine: (i) The shape of frozen droplets (2) The occurrence of collisions of partly frozen or of frozen and liquid droplets (3) The statistics on the freezing temperatures of individual free-falling droplets A considerable number of droplets were found to have a nonspherical shape after freezing because of various protuberances and frost growth, and droplet aggregates formed by collision. The observed frequency of collision of partly frozen droplets showed good order of magnitude agreement with the frequency computed from theoretical collection efficiencies. The freezing temperature statistics indicated a general similarity of the data to those obtained for droplets frozen on a metallic surface in previous experiments.

Dorsch, Robert G.; Levine, Joseph

1952-01-01

64

Freezing singularities in water drops Oscar R. Enrquez, lvaro G. Marn, Koen G. Winkels, and Jacco H. Snoeijer  

E-print Network

on the glass using a syringe pump. To increase contrast and observe the freezing front, red food dye was addedFreezing singularities in water drops Oscar R. Enríquez, Álvaro G. Marín, Koen G. Winkels://pof.aip.org/about/rights_and_permissions #12;PHYSICS OF FLUIDS 24, 091102 (2012) (a) (c) (b) (d) FIG. 1. Four snapshots of the freezing process

Snoeijer, Jacco

65

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

PubMed

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 thermodynamically consistent descriptions of liquid and solid (ice VII) water, relationships for phase coexistence, and a time-dependent transition description to simulate freezing dynamics. Continuum calculations using the water model demonstrate that, unlike single shock compression, multiple shock compression results in pressure-temperature conditions where the ice VIII phase is thermodynamically favored over the liquid phase. Wave profile measurements, using laser interferometry, were obtained with quartz and sapphire windows at a peak pressure of 5 GPa. For water confined between sapphire windows, numerical simulations corresponding to a purely liquid response are in excellent agreement with the measured wave profile. For water confined between quartz windows (to provide a nucleating surface), wave profile measurements demonstrate a pure liquid response for an incubation time of approximately 100 ns followed by a time-dependent transformation. Analysis of the wave profiles after the onset of transformation suggests that water changes from a metastable liquid to a denser phase, consistent with the formation of a high-pressure ice phase. Continuum analyses and simulations underscore the need for multiple time scales to model the freezing transition. Findings from the present continuum work are extremely consistent with optical results reported previously. These studies constitute the first comprehensive investigation reported for freezing of a liquid at very short time scales. PMID:16122330

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

2005-08-01

66

Water relations in freeze-dried powdered shortenings from babassu fat  

Microsoft Academic Search

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

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

1998-01-01

67

Separation of water-in-oil emulsions by freeze\\/thaw method and microwave radiation  

Microsoft Academic Search

In this paper, the demulsification has been achieved with the use of freeze\\/thaw (F\\/T) method and microwave radiation (MWR). The object of investigation were emulsion samples prepared by mixing the metal-working-oil, FESOL 09, produced by FAM, Krusevac, Serbia, and deionized water. F\\/T method has been successfully applied for the removal of oil from emulsions in our previous work. In this

Vladana Rajakovi?; Dejan Skala

2006-01-01

68

Freezing of Water next to Solid Surfaces Probed Using Sum-Frequency Generation Spectroscopy  

NASA Astrophysics Data System (ADS)

The control of ice formation next to solid surfaces is important in many technological applications such as de-icing for aircrafts and generation of power using wind turbines. We have studied the water-ice transition next to sapphire surface to understand the freezing transition and nucleation of ice. The infrared-visible sum frequency generation spectroscopy is sensitive to the structure and orientation of water molecules next to the solid interface and provides direct information on transition kinetics at the interface. The differences in the nucleation kinetics will be discussed for water in contact with hydrophilic and hydrophobic surfaces.

Anim-Danso, Emmanuel; Kurian, Anish; Ge, Liehui; Alizadeh, Azar; Dhinojwala, Ali

2012-02-01

69

Fabrication of two-dimensional nanosheets via water freezing expansion exfoliation.  

PubMed

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. PMID:25414167

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

2014-12-12

70

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

Microsoft Academic Search

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

Hidekazu Sasaki; Kazuo Ichimura; Kunihiko Okada; Masayuki Oda

1998-01-01

71

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

72

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

73

On the freezing behavior and diffusion of water in proximity to single-supported zwitterionic and anionic bilayer lipid membranes  

NASA Astrophysics Data System (ADS)

We compare the freezing/melting behavior of water hydrating single-supported bilayers of a zwitterionic lipid DMPC with that of an anionic lipid DMPG. For both membranes, the temperature dependence of the elastically scattered neutron intensity indicates distinct water types undergoing translational diffusion: bulk-like water probably located above the membrane and two types of confined water closer to the lipid head groups. The membranes differ in the greater width \\Delta T of the water freezing transition near the anionic DMPG bilayer (\\Delta T \\sim 70\\ \\text{K}) compared to zwitterionic DMPC (\\Delta T \\sim 20\\ \\text{K}) as well as in the abruptness of the freezing/melting transitions of the bulk-like water.

Miskowiec, A.; Buck, Z. N.; Brown, M. C.; Kaiser, H.; Hansen, F. Y.; King, G. M.; Taub, H.; Jiji, R.; Cooley, J. W.; Tyagi, M.; Diallo, S. O.; Mamontov, E.; Herwig, K. W.

2014-07-01

74

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

75

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

76

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

SciTech Connect

TASK 45 FIELD DEPLOYMENT EVALUATION OF THE FREEZE-THAW/ EVAPORATION (FTE ) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS coupling evaporation with freezing. This offers operators a year- round method for treating produced water. Treating water with the FTE process reduces the volume of water to be disposed of as well as purifying the water to a level acceptable for watering livestock and agricultural lands. This process is currently used at two evaporation facilities, one in the San Juan Basin in New Mexico and one in the Green River Basin in Wyoming. the freezing point below that of pure water. When such a solution is cooled below 32EF, relatively pure ice crystals form, along with an unfrozen brine solution that contains elevated concentrations of salts. Because of the brine's high concentration of these constituents, its density is greater than that of the ice, and the purified ice and brine are easily separated. Coupling the natural processes of freezing and evaporation makes the FTE process a more cost- effective and efficient method for the treatment and disposal of produced water and allows for year-round operation of an FTE facility. drops below 32 F, produced water is automatically pumped from a holding pond and sprayed onto a freezing pad. The freezing pad consists of an elevated framework of piping with regularly placed, upright, extendable spray heads similar to those used to irrigate lawns. As the spray freezes, an ice pile forms over the elevated framework of pipes, and the brine, with an elevated constituent concentration, drains from the ice pile. The high-salinity brine, identified by its high electrical conductivity, is separated using automatic valves and pumped to a pond where it can subsequently be disposed of by conventional methods. As the ice pile increases in height, the sprayers are extended. When the ice on the freezing pad melts, the relatively pure water is pumped from the freezing pad and discharged or stored for later use . No new wastes are generated by the FTE process. and the U. S. Department of Energy has been conducted since 1992 to develop a commercial FTE purification process for produced waters. Numeric process and economic modeling, as well as the laboratory-scale process simulation that confirmed the technical and economic feasibility of the process, was performed by B. C. Technologies, Ltd., and the University of North Dakota Energy & Environmental Research Center (EERC) from 1992 to 1995. They then conducted a field evaluation from 1995 to 1997 in New Mexico's San Juan Basin at a conventional evaporation facility operated by Amoco Production Company. The results of this evaluation confirmed that the FTE process has significant commercial economic potential. A new facility was designed in 1998, and its construction is expected to begin in 1999.

Ames A. Grisanti; James A. Sorensen

1999-05-01

77

Freezing of water-saturated porous media in the presence of natural convection: Experiments and analysis  

SciTech Connect

Freezing of superheated water-porous media (glass beads) contained in a rectangular test cell has been studied both experimentally and numerically. The effects of liquid superheat and imposed temperature difference were investigated. When the superheat across the liquid region was small the flow in the porous media was weak, and the interface was almost planar. For larger superheats, natural convection flow and the solidification front shape and velocity were found to depend on the imposed temperature and the permeability of the porous medium. Due to the density inversion of water, the rate of freezing was higher, either at the top or at the bottom of the cell, depending on the amount of superheat. The measured temperature distributions were compared with predictions of numerical model that considered both conduction in the solid and natural convection in the liquid region. This model is based on volumetric averaging of the macroscopic transport equations, with phase change assumed to occur volumetrically over a small temperature range. Both Brinkman and Forchheimer extensions were added to the Darcy equations. The effect of density inversion of water on the fluid flow and heat transfer has been modeled. Good agreement has been found between the experimental data and numerical predictions.

Chellaiah, S.; Viskanta, R. (Purdue Univ., West Lafayette, IN (United States))

1989-05-01

78

Freeze-drying of enzymes in case of water-binding and non-water-binding substrates.  

PubMed

Enzymes typically have a critical instability, which dominates both formulation and process development. In this paper, the ability to preserve the enzyme activity during freeze-drying was investigated for both water-binding and non-water-binding substrates. For this purpose, acid phosphatase was used as model protein. In addition, a procedure for the fast development of a freeze-drying cycle is shown. For the secondary drying part, the effect of processing temperature and time on enzyme activity was investigated. The enzyme activity decreased continuously during secondary drying, with a dramatic drop associated with processing temperatures higher than 293 K. Besides product temperature, the residual moisture level and water mobility are also important. As the residual moisture level and water mobility depend on the product formulation, the stabilizing effect against the enzyme deactivation was studied for a number of formulations which contain different additives, that is, sucrose, lactose, mannitol, and poly-vinylpyrrolidone, with a dramatic activity loss associated with crystallizing excipients. This study also confirmed that not all water-binding substrates can successfully protect the enzyme against deactivation. In fact, water-binding substrates containing reducing sugars (lactose) showed the highest loss of activity. PMID:23500114

Pisano, Roberto; Rasetto, Valeria; Barresi, Antonello A; Kuntz, Florent; Aoude-Werner, Dalal; Rey, Louis

2013-11-01

79

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

80

Effect of Water Content on the Thermal Inactivation Kinetics of Horseradish Peroxidase Freeze-Dried from Alkaline pH  

Microsoft Academic Search

The thermal inactivation of horseradish peroxidase freeze-dried from solutions of different pH (8, 10 and 11.5, measured at 25 C) and equilibrated to different water contents was studied in the temperature range from 110 to 150 C. The water contents studied (0.0, 1.4, 16.2 and 25.6 g water per 100 g of dry enzyme) corresponded to water activities of 0.0,

M. A. Lemos; J. C. Oliveira; J. A. Saraiva

2001-01-01

81

Water sorption properties, molecular mobility and probiotic survival in freeze dried protein-carbohydrate matrices.  

PubMed

The moisture uptake and molecular mobility of freeze-dried powders containing whey protein isolate-carbohydrate matrices (1WPI:2maltodextrin; 1WPI:1maltodextrin:1d-glucose; and 1WPI:1maltodextrin:1l-glucose) and encapsulated Lactobacillus rhamnosus GG (LGG) in these matrices were investigated at 25 °C and 33% and 70% relative humidity (RH). The inactivation rate constant for probiotics in freeze-dried matrices were positively correlated (R(2) = 0.98) to moisture uptake and molecular mobility measured by NMR relaxometry. The stability of probiotics in glassy protein-carbohydrate matrices was dependent on the composition of the matrix. The partial substitution of maltodextrin with glucose (d- or l-) which improved microbial survival at 33% RH was related to the reduced molecular mobility and lower water uptake of the matrix. This study suggests that moisture uptake properties and molecular mobility of the matrix composition, as opposed to the relative humidity of the environment, are better determinants of probiotic viability during storage. Dynamic vapour sorption and NMR relaxometry are promising tools to assist in the selection of protein-carbohydrate matrices for enhancing probiotic viability during storage. PMID:23851914

Hoobin, Pamela; Burgar, Iko; Zhu, ShouChuang; Ying, DanYang; Sanguansri, Luz; Augustin, Mary Ann

2013-09-01

82

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

83

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

84

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

85

Freeze substitution followed by low melting point wax embedding preserves histomorphology and allows protein and mRNA localization techniques.  

PubMed

Fixation and embedding are major steps in tissue preservation for histological analysis. However, conventional fixatives like aldehyde-based solutions usually mask tissular epitopes preventing their immunolocalization. Alternative fixation methods used to avoid this drawback, such as cryopreservation, alcohol- or zinc salts-based fixatives do not efficiently preserve tissue and cell morphology. Likewise, paraffin and resin embedding, commonly used for thin sectioning, frequently damage epitopes due to the clearing agents and high temperatures needed along the embedding procedure. Alternatives like cryosectioning avoid the embedding steps but yield sections of poorer quality and are not suitable for all kinds of samples. To overcome these handicaps, we have developed a method that preserves histoarchitecture as well as tissue antigenic properties. This method, which we have named CryoWax, involves freeze substitution of the samples in isopentane and methanol, followed by embedding in low melting point polyester wax. CryoWax has proven efficient in obtaining thin sections of embryos and adult tissues from different species, including amphioxus, zebrafish, and mouse. CryoWax sections displayed optimal preservation of tissue morphology and were successfully immunostained for fixation- and temperature-sensitive antigens. Furthermore, CryoWax has been tested for in situ hybridization application, obtaining positive results. PMID:20830701

Durán, Iván; Marí-Beffa, Manuel; Santamaría, Jesús A; Becerra, José; Santos-Ruiz, Leonor

2011-05-01

86

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

Microsoft Academic Search

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

Y. Yamada; F. Sakuma; A. Ono

2000-01-01

87

Evaluation of tunable diode laser absorption spectroscopy for in-process water vapor mass flux measurements during freeze drying.  

PubMed

The goal of this work was to demonstrate the use of Tunable Diode Laser Absorption Spectroscopy (TDLAS) as a noninvasive method to continuously measure the water vapor concentration and the vapor flow velocity in the spool connecting a freeze-dryer chamber and condenser. The instantaneous measurements were used to determine the water vapor mass flow rate (g/s). The mass flow determinations provided a continuous measurement of the total amount of water removed. Full load runs of pure water at different pressure and shelf temperature settings and a 5% (w/w) mannitol product run were performed in both laboratory and pilot scale freeze dryers. The ratio of "gravimetric/TDLAS" measurements of water removed was 1.02 +/- 0.06. A theoretical heat transfer model was used to predict the mass flow rate and the model results were compared to both the gravimetric and TDLAS data. Good agreement was also observed in the "gravimetric/TDLAS" ratio for the 5% mannitol runs dried in both freeze dryers. The endpoints of primary and secondary drying for the product runs were clearly identified. Comparison of the velocity and mass flux profiles between the laboratory and pilot dryers indicated a higher restriction to mass flow for the lab scale freeze dryer. PMID:17221854

Gieseler, Henning; Kessler, William J; Finson, Michael; Davis, Steven J; Mulhall, Phillip A; Bons, Vincent; Debo, David J; Pikal, Michael J

2007-07-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

89

Freeze Brand Marking of Steelhead Trout and Chinook Salmon Juveniles for Water Budget Studies, Idaho, 1985 Annual Report.  

SciTech Connect

During the fall of 1984 and spring of 1985, 362,428 chinook salmon (Oncorhynchus tshawtscha) and steelhead trout (Salmo gairdneri) juveniles were freeze branded for Water Budget Center - Downstream Smolt Monitoring Studies. Of these, 106,361 fish received a coded wire tag. Release of the freeze brand groups began March 20, 1985 and were completed by June 4, 1985. After brand loss and mortality, there were 133,025 spring chinook, 25,600 summer chinook, 33,850 fall chinook, 65,125 A-run steelhead, and 62,400 B-run steelhead released with brands.

Nelson, V. Lance

1986-06-01

90

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

91

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

92

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

PubMed

Changes in water content and dry weight were determined in control cells and those induced to cold harden in response to abscisic acid (ABA) treatment (7.5 x 10(-5) molar). Bromegrass (Bromus inermis Leyss cv Manchar) cells grown in suspension culture at room temperature (23 degrees C) for 7 days acclimated to -28 degrees C (LT(50)) when treated with ABA, or to -5 degrees C when untreated. ABA significantly reduced cell growth rates at 5 and 7 days after treatment. Growth reduction was due to a decrease in cell number rather than cell size. When the cell water content was expressed as percent water (percent H(2)O) or as grams water per gram dry weight (gram H(2)O/gram dry weight [g DW]), the water content of hardy, ABA-treated cells decreased from 85% to 77% or from 6.4 to 3.3 g H(2)O/g DW in 7 days. Control cell water content remained static at approximately 87% and 7.5 g H(2)O/g DW. However, cell water content, expressed as milligrams water per million cells (milligram H(2)O/10(6) cells), did not differ in ABA-treated or control cells. The dry matter content of ABA-treated cells, expressed as milligram DW/10(6) cells increased to 3.3 milligram/10(6) cells in 7 days, whereas the dry weight of the control cells remained between 1.4 to 2.1 milligrams/10(6) cells. The osmotic potential of ABA-treated cells decreased by the fifth day while that of control cells increased significantly and then decreased by day 7. Elevated osmotic potentials were not associated with increased ion uptake. In contrast to much published literature, these results suggest that cell water content does not decrease in ABA-treated cells during the induction of freezing tolerance, rather the dry matter mass per cell increased. Cell water content may be more accurately expressed as a function of cell number when accompanying changes to dry cell matter occur. PMID:16667488

Tanino, K; Weiser, C J; Fuchigami, L H; Chen, T H

1990-06-01

93

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

94

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

95

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

96

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

97

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

98

Reply to Comment on "Pointy ice-drops: how water freezes into a singular shape", Am. J. Phys. 80, 764-771 (2012)  

E-print Network

Comment illustrates that the cusp formation is very robust, and indeed, with a block of dry ice it canReply to Comment on "Pointy ice-drops: how water freezes into a singular shape", Am. J. Phys. 80 with a syringe is simple and very elegant, and provides easy access to the shape of the ice halfway the freezing

Snoeijer, Jacco

99

Vacuum Freeze-Drying, a Method Used To Salvage Water-Damaged Archival and Library Materials: A RAMP Study with Guidelines.  

ERIC Educational Resources Information Center

This Records and Archives Management Programme (RAMP) study covers the conservation of archival documents and the application of freeze-drying to the salvage of documents damaged by flood. Following an introductory discussion of the hazards of water, the study presents a broad summary of data on freeze-drying, including the behavior of…

McCleary, John M.

100

Alterations in Water Status, Endogenous Abscisic Acid Content, and Expression of rab78 Gene during the Development of Freezing Tolerance in Arabidopsis fhaliana  

Microsoft Academic Search

Treatments as diverse as exposure to low temperature (LT), exogenous abscisic acid (ABA), or drought resulted in a 4 to 5'C increase in freezing tolerance of the annual herbaceous plant Arabidopsis thaliana. To correlate the increase in freezing toler- ante with the physiological changes that occur in response to these treatments, we studied the alterations in water status, endogenous ABA

Viola Ling; Einar Mantyla; Bjorn Welin; Bjorn Sundberg; E. Tapio Palva

101

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

102

The effect of water-soluble polymers on the microstructure and properties of freeze-cast alumina ceramics  

NASA Astrophysics Data System (ADS)

Porous ceramics can be divided into three separate classes based on their pore size: microporous ceramics with pores less than 2 nm, mesoporous ceramics with pores in the range of 2--50 nm and macroporous ceramics with pores that are greater than 50 nm. In particular, macroporous ceramics are used in a variety of applications such as refractories, molten metal filtration, diesel particulate filters, heterogeneous catalyst supports and biomedical scaffolds. Freeze casting is a novel method used to create macroporous ceramics. In this method growing ice crystals act as a template for the pores and are solidified, often directionally, through a ceramic dispersion and removed from the green body through a freeze drying procedure. This method has attracted some attention over the past few years due to its relative simplicity, flexibility and environmental friendliness. On top of this freeze casting is capable of producing materials with high pore volume fractions, which is an advantage over processing by packing and necking of particles, where the pore volume fraction is typically less than 50%. Many of the basic processing variables that affect the freeze cast microstructure, such as the temperature gradient, interfacial velocity and solid loading of the dispersion have been well established in the literature. On the other hand, areas such as the effect of additives on the microstructure and mechanical properties have not been covered in great detail. In this study the concept of constitutional supercooling from basic solidification theory is used to explain the effects of two water-soluble polymers, polyethylene glycol and polyvinyl alcohol, on the microstructure of freeze cast alumina ceramics. In addition, changes in the observed microstructure will be related to experimentally determined values of permeability and compressive strength.

Pekor, Christopher Michael

103

ATS 351, Spring 2010 Water in the Atmosphere 55 points  

E-print Network

, explain why is it more effective to water your lawn in the evening than it is on a hot afternoonATS 351, Spring 2010 Lab #4 Water in the Atmosphere ­ 55 points Please show your work for calculations Question #1: Phases of water (10 points) a) (3 points) Please match the process to the appropriate

Rutledge, Steven

104

NATURAL FREEZING SURVIVAL IN ANIMALS  

Microsoft Academic Search

Natural freeze-tolerance supports the winter survival of many animals including numerous terrestrial insects, many intertidal marine invertebrates, and selected species of terrestrially hibernating amphibians and reptiles. Freeze-tolerant an- imals typically endure the conversion of 50% or more of total body water into extracellular ice and employ a suite of adaptations that counter the negative con- sequences of freezing. Specific adaptations

Kenneth B. Storey; Janet M. Storey

1996-01-01

105

A study of freezing-melting hysteresis of water in different porous materials. Part II: surfactant-templated silicas.  

PubMed

The freezing-melting hysteresis of water in mesoporous silicas MCM-48, MCM-41 and SBA-16 has been studied by NMR cryoporometry. The hysteresis in MCM-48 was found to exhibit nearly parallel branches, matching type H1 hysteresis that had been observed earlier in controlled pore glass. The same type of hysteresis is observed in two of three different-sized MCM-41 under study (a pore diameter of 3.6 and 3 nm), superimposed with a secondary, extremely broad, type H3 hysteresis. No hysteresis was found in the smallest MCM-41 with a pore diameter < 3 nm. Finally, water in SBA-16 exhibits type H2 hysteresis with the freezing branch being essentially steeper than the melting one, which is attributed to a pore blockage upon freezing, similar to what we observed earlier in Vycor porous glass. The data were analyzed using the model of curvature-dependent metastability of a solid phase upon melting; the validity of this model has been discussed. PMID:21837315

Petrov, Oleg; Furó, István

2011-09-28

106

Freezing curve-based monitoring to quickly evaluate the viability of biological materials subject to freezing or thermal injury.  

PubMed

This paper is aimed at investigating the roles of freezing dynamics of a liquid droplet to characterize the properties of the material. In particular, freezing curve-based monitoring was proposed to quickly evaluate the viability of biological materials subject to freezing, re-warming, or other kinds of injury, which is an extremely important issue in practices such as cryobiology, hyperthermia, or freshness evaluation of bio-samples. An integrated micro analysis device was fabricated which is simple in structure and cheap to make. Preliminary freezing results demonstrated that minor changes in a biological material due to freezing or warming injury might result in a significant deviation of its freezing curve from that of the intact biomaterials. Several potential thermal indexes to quantify the material features were pointed out. Further, experiments were performed on some freezing and thawing processes of small amount of water on a cooling surface to test the effects of droplet sizes, measurement sites, cooling strength, and cooling geometry, etc., on the freezing responses of a water droplet. Their implementation in developing a new micro analysis system were suggested. This freezing curve-based monitoring method may open a new strategy for the evaluation of biomaterials subject to destruction in diverse fields. PMID:12844203

Liu, Jing; Zhou, Yi-Xin

2003-09-01

107

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

108

21 CFR 1240.83 - Approval of watering points.  

Code of Federal Regulations, 2012 CFR

...and Use of Potable Water § 1240.83 ...Commissioner of Food and Drugs shall approve any...point if (1) the water supply thereat...Agency's Primary Drinking Water Regulations as...Commissioner of Food and Drugs may base his...

2012-04-01

109

21 CFR 1240.83 - Approval of watering points.  

...and Use of Potable Water § 1240.83 ...Commissioner of Food and Drugs shall approve any...point if (1) the water supply thereat...Agency's Primary Drinking Water Regulations as...Commissioner of Food and Drugs may base his...

2014-04-01

110

21 CFR 1240.83 - Approval of watering points.  

Code of Federal Regulations, 2010 CFR

...and Use of Potable Water § 1240.83 ...Commissioner of Food and Drugs shall approve any...point if (1) the water supply thereat...Agency's Primary Drinking Water Regulations as...Commissioner of Food and Drugs may base his...

2010-04-01

111

21 CFR 1240.83 - Approval of watering points.  

Code of Federal Regulations, 2011 CFR

...and Use of Potable Water § 1240.83 ...Commissioner of Food and Drugs shall approve any...point if (1) the water supply thereat...Agency's Primary Drinking Water Regulations as...Commissioner of Food and Drugs may base his...

2011-04-01

112

21 CFR 1240.83 - Approval of watering points.  

Code of Federal Regulations, 2013 CFR

...and Use of Potable Water § 1240.83 ...Commissioner of Food and Drugs shall approve any...point if (1) the water supply thereat...Agency's Primary Drinking Water Regulations as...Commissioner of Food and Drugs may base his...

2013-04-01

113

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

Microsoft Academic Search

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

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

114

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

Microsoft Academic Search

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

M. E. Loik; P. S. Nobel

1993-01-01

115

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

116

Initiation of Freezing a Super-cooled Water Droplet in Oil by Colliding with the Electrodes for Applying Uniform DC Electric Field  

NASA Astrophysics Data System (ADS)

A water droplet injected into silicone oil, to which uniform electric field is applied by use of a pair of electrode plate, reciprocates colliding alternately with each electrode plate. This paper proposes to use the collision to augment initiation of freezing nucleation of super-cooling water droplet, and deals with the characteristics of the phenomena. The shuttle migration of a droplet between electrodes and initiation of freezing is photographed by use of a video camera, and the phenomena are analyzed on a monitor. As a result, the freezing initiation of the droplet is observed while the droplet is touched to the negative electrode plate. Relative frequency of the initiation is shown by the super-cooling degree and the electric field strength. The upper limitation of the temperature at which all sample droplets initiate to freeze is -3°C. Characteristics of the initiation are clarified and the effectiveness of this method is shown.

Tochitani, Yoshiro; Kawasaki, Naoto

117

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

Microsoft Academic Search

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

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

2009-01-01

118

Rehydration of freeze-dried food from non-potable water: An application for advanced polymer membranes  

SciTech Connect

Considerable progress has been made in recent years in the development of polymer membranes with physical and chemical properties that make them useful for specialty separations. The potential use of polymer membranes for rehydrating freeze-dried food using non-potable water sources is a noble concept that may be possible using commercially available membranes. To use any of the commercially available membranes, the candidate membrane needs to meet the following requirements: (1) permeable to water, but impermeable to salts and microorganisms, (2) reasonable membrane flux at low pressure (760 mm Hg or less) and (3) comply with Food and Drug Administration (FDA) regulations for food contact. To determine the feasibility of using polymer membranes for a self-hydrating packaging system to reconstitute freeze-dried foods, several commercially available membranes were screened according to (1) hydration rate of membrane, (2) water flux through membrane, (3) passage of microorganisms through membrane, and (4) salt rejectivity of membrane. From these screening tests, several membranes were identified as candidate membranes for this application. These membranes were used in developing self-hydrating prototype packaging systems. The sensitivity of the systems to food composition and temperature was studied.

Schimmel, K.A.; Wurie, A.; Ilias, S. [North Carolina A and T State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering; Pegram, J.E. [Research Triangle Inst., Research Triangle Park, NC (United States). Dept. of Polymer Science

1995-06-01

119

Flight Instrument for Measurement of Liquid-Water Content in Clouds at Temperatures Above and Below Freezing  

NASA Technical Reports Server (NTRS)

A principle formerly used in an instrument for cloud detection was further investigated to provide a simple and rapid means for measuring the liquid-water content of clouds at temperatures above and below freezing. The instrument consists of a small cylindrical element so operated at high surface temperatures that the impingement of cloud droplets creates a significant drop in the surface temperature. ? The instrument is sensitive to a wide range of liquid-water content and was calibrated at one set of fixed conditions against rotating multicylinder measurements. The limited conditions of the calibration Included an air temperature of 20 F, an air velocity of 175 miles per hour, and a surface temperature in clear air of 475 F. The results obtained from experiments conducted with the instrument indicate that the principle can be used for measurements in clouds at temperatures above and below freezing. Calibrations for ranges of airspeed, air temperature, and air density will be necessary to adapt the Instrument for general flight use.

Perkins, Porter J.

1951-01-01

120

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

121

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

Microsoft Academic Search

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

Diedrich T. F. Möhlmann

2008-01-01

122

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

PubMed

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

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

2002-11-01

123

Effect of addition of coconut water (Cocos nucifera) to the freezing media on post-thaw viability of boar sperm.  

PubMed

The aims of this experiment were to evaluate the addition of coconut water in natura to the freezing media, compare the effect of deionized water vs filtered water of coconut over the post-thaw seminal characteristics, and evaluate the effect of the deionized water and in natura coconut water on the seminal characteristics of boar sperm at different post-thaw times. Thirty-four ejaculates were used divided in three aliquots which received one of the following treatments (T): T1, LEY (bidistilled water, lactose, and egg yolk) and LEYGO (LEY + glycerol and Orvus ET paste); T2, LEY(A) (coconut deionized water, lactose, and egg yolk)-LEYGO(A); and T3, LEY(B) (in natura coconut water, lactose, and egg yolk)-LEYGO(B). Samples of boar semen were frozen according to the Westendorf method, thawed at 38°C, and evaluated at three incubation times (0, 30, and 60 min). Seminal characteristics assessed were motility (Mot), acrosomal integrity (AInt), membrane integrity (MInt), and mitochondrial activity (MAct). T1 showed a higher percentage of viable sperm than T3 (Mot 36.5 vs 5.4 %, AInt 61.8 vs 41.2 %, MInt 50.4 vs 41.3 %, and MAct 56.9 vs 50.5 %). T2 kept a higher percentage of viable sperm at all incubation times. In natura coconut water showed a detrimental effect over the viability of the frozen-thawed boar semen. Deionized coconut water improved the boar semen viability post-thaw, outperforming results of in natura coconut water. PMID:22700284

Bottini-Luzardo, María; Centurión-Castro, Fernando; Alfaro-Gamboa, Militza; Aké-López, Ricardo; Herrera-Camacho, José

2012-12-01

124

BACTERIAL COLONIZATION OF POINT-OF-USE WATER TREATMENT DEVICES  

EPA Science Inventory

Point-of-use water treatment devices were investigated for types of organisms that may colonize these filters, the magnitude of microbial post colonization release in the product water during daily use or after periods of non use, and the impact of tap waters of marginal bacterio...

125

Decontamination of poultry carcasses using steam or hot water in combination with rapid cooling, chilling or freezing of carcass surfaces.  

PubMed

The effects of the application of steam at atmospheric pressure for times up to 20 s on the numbers of inoculated Campylobacter jejuni and Escherichia coli on whole chicken carcasses were investigated in a pilot steam cabinet. Steam treatments reduced the numbers of C. jejuni AR6 by ca. 1.8, 2.6 and 3.3 log(10) cfu cm(-2) in 10, 12 and 20 s, respectively. Corresponding reductions in numbers of E. coli K12 were 1.7, 2.3 and 2.8 log(10) cfu cm(-2). However, such treatments caused the skin to shrink and change colour. The optimum treatment for maximum reductions of C. jejuni and E. coli, least skin shrinkage and change of colour was concluded to be <12 s. Further work was carried out to determine whether a modified air chilling system in combination with steam or hot water decontamination treatments could be used to reduce numbers of pathogens, particularly campylobacters, on the surface of poultry carcasses. Whole chicken carcasses inoculated with C. jejuni and E. coli were either not treated, treated with steam at atmospheric pressure for up to 10 s or treated with hot water at 80 degrees C for up to 20 s, then either chilled by crust freezing, chilled at 0 degrees C, or chilled at 15 degrees C, in a pilot chilling chamber. The optimum combination was treatment with water at 80 degrees C for 20 s followed by crust freezing, which reduced the numbers of C. jejuni and E. coli by ca. 2.9 and 3.2 log(10) cfu cm(-2), respectively, without extensive degradation of carcass appearance. PMID:17140687

James, Christian; James, Stephen J; Hannay, Neil; Purnell, Graham; Barbedo-Pinto, Catia; Yaman, Hilmi; Araujo, Marlene; Gonzalez, M Luisa; Calvo, Javier; Howell, Mary; Corry, Janet E L

2007-03-10

126

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

Microsoft Academic Search

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

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

2006-01-01

127

Freeze-fracture cytochemistry: replicas of critical point-dried cells and tissues after fracture-label.  

PubMed

Applications of the new fracture-labeling techniques for the observation of cytochemical labels on platinum-carbon replicas are described. Frozen cells, embedded in a cross-linked protein matrix, and frozen tissues are fractured with a scalpel under liquid nitrogen, thawed, labeled, dehydrated by the critical point drying method, and replicated. This method allows direct, high-resolution, two-dimensional chemical and immunological characterization of the cellular membranes in situ, as well as detection of sites within cross-fractured cytoplasm and extracellular matrix. PMID:7244630

da Silva, P P; Kachar, B; Torrisi, M R; Brown, C; Parkison, C

1981-07-10

128

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

...2014-07-01 2014-07-01 false Bottled water, point-of-use, and point-of-entry...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Exemptions...

2014-07-01

129

Liquid-Liquid Critical Point in Heavy Water  

Microsoft Academic Search

According to the liquid-liquid critical-point hypothesis about water, two liquid waters exist at low temperatures and are supposed to be merged at a critical point. The low-temperature metastable melting curves of D2O ices have been measured. It is found that the melting curve of D2O ice III is smoothly curved around 25 MPa and 238 K, whereas the melting curve

Osamu Mishima

2000-01-01

130

MOST CURRENT SECTION 305(B) LISTED WATERS - POINT EVENTS  

EPA Science Inventory

River segments, lakes, and estuaries designated under Section 305(b) of the Clean Water Act. Most Current 305(b) Waterbodies coded onto route.rch (Transport and Coastline Reach) feature of NHD to create Point Events. Point events are attached to a reach in NHD to represent assess...

131

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

PubMed

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 24 h), drip loss, and salt-induced water uptake were measured. Reflectance measurements were recorded from 400 to 2,500 nm in both raw and freeze-dried breast meat samples. Raw and freeze-dried samples had similar spectra in the visible region (400-750 nm), but the freeze-dried samples exhibited numerous bands in the NIR region (750-2,500 nm) corresponding to muscle proteins and lipids that were not observed in the NIR spectra of the raw samples. Linear discriminate analyses were used to classify fillets as high-WHC or low-WHC according to predicted meat quality characteristics. Using the visible spectra (400-750 nm), fillets could be correctly classified into high-WHC and low-WHC groups based on drip loss and salt-induced water uptake with 88 to 92% accuracy in raw samples and 79 to 86% accuracy in freeze-dried samples. Using the NIR spectra (750-2,500 nm), fillets could be correctly classified into high-WHC and low-WHC groups with 74 to 76% accuracy in raw samples and 85 to 86% accuracy in freeze-dried samples. Thus, freeze-drying enhanced the accuracy of WHC classification using the NIR portion of the spectra. Data from this study demonstrate the potential for utilizing vis/NIR spectroscopy as a method for classifying broiler breast meat according to WHC. PMID:24864280

Bowker, B; Hawkins, S; Zhuang, H

2014-07-01

132

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

PubMed

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

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

2009-03-01

133

The effect of water content, cooling rate, and growth temperature on the freezing temperature of 4 Tillandsia species  

E-print Network

in their tissues (Levitt, 1972). Two types of freezing occur in plants: extracellular and intracellular (Asahina, 1978; Levitt, 1972; 1978). Many plants are able to tolerate extracellular freezing (Levitt, 1972; 1978), which results from slow cooling rates (lo...-5oC / hr) (Levitt, 1972) . During extracellular freezing, ice forms in intracellular spaces and / or extracellularly between cell walls and protoplasts (Asahina, 1978; Levitt, 1972) creating a vapor pressure gradient between the ice...

Hagar, Christopher Flint

2012-06-07

134

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

135

Suppression of Sub-surface Freezing in Free-Standing Films of a Coarse-grained Model of Water  

E-print Network

Freezing in the vicinity of water-vapor interfaces is of considerable interest to a wide range of disciplines, most notably the atmospheric sciences. In this work, we use molecular dynamics and two advanced sampling techniques, forward flux sampling and umbrella sampling, to study homogeneous nucleation of ice in free-standing thin films of supercooled water. We use a coarse-grained monoatomic model of water, known as mW, and we find that in this model a vapor-liquid interface suppresses crystallization in its vicinity. This suppression occurs in the vicinity of flat interfaces where no net Laplace pressure in induced. Our free energy calculations reveal that the pre-critical crystalline nuclei that emerge near the interface are thermodynamically less stable than those that emerge in the bulk. We investigate the origin of this instability by computing the average asphericity of nuclei that form in different regions of the film, and observe that average asphericity increases closer to the interface, which is c...

Haji-Akbari, Amir; Sarupria, Sapna; Debenedetti, Pablo G

2014-01-01

136

Suppression of sub-surface freezing in free-standing thin films of a coarse-grained model of water.  

PubMed

Freezing in the vicinity of water-vapor interfaces is of considerable interest to a wide range of disciplines, most notably the atmospheric sciences. In this work, we use molecular dynamics and two advanced sampling techniques, forward flux sampling and umbrella sampling, to study homogeneous nucleation of ice in free-standing thin films of supercooled water. We use a coarse-grained monoatomic model of water, known as mW, and we find that in this model a vapor-liquid interface suppresses crystallization in its vicinity. This suppression occurs in the vicinity of flat interfaces where no net Laplace pressure in induced. Our free energy calculations reveal that the pre-critical crystalline nuclei that emerge near the interface are thermodynamically less stable than those that emerge in the bulk. We investigate the origin of this instability by computing the average asphericity of nuclei that form in different regions of the film, and observe that average asphericity increases closer to the interface, which is consistent with an increase in the free energy due to increased surface-to-volume ratios. PMID:25354427

Haji-Akbari, Amir; DeFever, Ryan S; Sarupria, Sapna; Debenedetti, Pablo G

2014-12-21

137

Water Flow and Heat Transport in Frozen Soil: Numerical Solution and Freeze-Thaw Applications  

Microsoft Academic Search

implicit numerical model for coupled heat transport and variably saturated water flow involving conditions both above and below zero Many of the processes that we try to formulate mathe- temperature. The method is based on a mixed formulation for both matically and simulate numerically today were already water flow and heat transport similar to the approach commonly used being studied

Klas Hansson; Jirka Simunek; Masaru Mizoguchi; Lars-Christer Lundin; M. Th. van Genuchten

2004-01-01

138

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

139

Growth patterns and interfacial kinetic supercooling at ice/water interfaces at which anti-freeze glycoprotein molecules are adsorbed  

NASA Astrophysics Data System (ADS)

Ice crystal growth in a supercooled solution containing proteins such as anti-freeze glycoproteins (AFGPs) is inhibited by its adsorption at the ice/water interface. Although these proteins have dramatic consequences for natural biological processes and technological applications, little is known about the dynamic mechanism of ice growth inhibition. One-directional growth experiments were carried out to observe the pattern formation at the ice/water interface growing from an aqueous AFGP solution. Typical zigzag patterns composed of flat prismatic {1 0 1¯ 0} interfaces were observed in the final quasi-stable growth state. By analyzing the zigzag patterns, we were able to directly determine the interfacial kinetic supercooling, ?T, at the interfaces of prismatic faces as a function of growth rate. ?T linearly increased with increasing growth rate in the range below a critical growth rate, but its dependence showed the reversed relationship above the critical growth rate. This growth rate dependency of ?T was qualitatively explained by the interaction between the rejection and incorporation rates of AFGP molecules at the growing interface.

Furukawa, Yoshinori; Inohara, Naomi; Yokoyama, Etsuro

2005-02-01

140

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

NASA Astrophysics Data System (ADS)

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

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

2007-04-01

141

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

Microsoft Academic Search

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

J. C. Zimmerman; N. Al-Abbadi

1987-01-01

142

NMR studies of non-freezing water in randomly packed beds of porous particles  

NASA Astrophysics Data System (ADS)

NMR water proton transverse relaxation time distributions are shown to provide valuable information about the distribution of ice and nonfreezing water in complex heterogeneous systems. In a model system consisting of randomly packed Sephadex beads the NMR data confirm that ice inside the porous Sephadex beads coexists as a two phase system with unfrozen dextran gel. The NMR relaxation technique is shown to provide complementary information to both differential scanning calorimetry and cryomicroscopy.

Hills, B. P.; Le Floc'h, G.

143

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

SciTech Connect

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

Bevel, A.; Hrudey, S.; Dudas, M.; Sego, D. [Univ. of Alberta, Edmonton, Alberta (Canada)

1996-11-01

144

The Soil Moisture Active/Passive (SMAP) Freeze/Thaw Product: Providing a Crucial Linkage between Earth's Water and Carbon Cycles  

NASA Astrophysics Data System (ADS)

Landscape transitions between seasonally frozen and thawed conditions occur each year over roughly 50 million square kilometers of Earth’s Northern Hemisphere, affecting surface meteorological conditions, ecological trace gas dynamics, energy exchange and hydrologic activity profoundly. NASA’s Soil Moisture Active-Pasiive (SMAP) mission, currently planned for launch in 2014, will employ a combined radiometer and high-resolution radar to measure surface soil moisture and freeze/thaw state, thus providing new opportunities for scientific advances and societal benefits. Major science objectives of SMAP support the understanding of processes linking terrestrial water, energy and carbon cycles, the quantification of net carbon flux and the extension of capabilities for weather and climate prediction models. The SMAP suite of data products will include global maps of landscape freeze/thaw state derived from L-band radar at 1-3 km spatial resolution with a 2-day refresh rate for the high northern latitudes (i.e. latitudes above 50 degrees north). The algorithm employed in derivation of the freeze/thaw product employs a temporal change detection scheme to delineate freeze/thaw state changes associated with temporal variations in landscape microwave dielectric constant properties. Development of the algorithm follows from application of legacy data sets provided by satellite radars, both scatterometers and Synthetic Aperture Radars (SARs), and radiometers. This presentation reviews algorithm development, product derivation and validation, product applications and associated SMAP science objectives addressed through the derived freeze/thaw data products. We review efforts in which contemporary and legacy active and passive microwave remote sensing data sets have been applied in prototyping the freeze/thaw product and its applications. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, and at the University of Montana under contract to the National Aeronautics and Space Administration.

McDonald, K. C.; Kimball, J. S.; Kim, Y.

2010-12-01

145

Performance of residential air-to-air heat exchangers during operation with freezing and periodic defrosts  

SciTech Connect

In a laboratory study of the performance of residential air-to-air heat exchangers during operation with freezing and periodic defrosts, freezing caused the temperature efficiency of a cross-flow heat exchanger to decrease at a rate ranging from 1.5 to 13.2 percentage points per hour. Much smaller rates of decrease in temperature efficiency, 0.6 to 2.0 percentage points per hour, occurred during tests with a counterflow heat exchanger. The rate of decrease in efficiency depended on the airstream temperatures and humidities and the duration of the period of freezing. The amount of time required to defrost the heat exchanger's core was 6 to 26% of the total operating time. The average temperature efficiency for freeze-defrost cycles ranged from 48 to 64% in tests of the cross-flow exchanger and 70 to 82% in tests of the counterflow exchanger. When the frequency and duration of defrosts were nearly optimal, approximately a 10 to 15 percentage point decrease in average temperature efficiency was attributed to the freezing and required defrosts. The results suggested that the rate of performance deterioration due to freezing can be reduced by avoiding small airflow passages that can easily be plugged with ice and by designing the exchanger so that condensed water does not drain toward the cold regions of the core. Based on this investigation, suggestions are made for future experimental studies of freezing and for improved control of freeze-protection systems. 1 reference, 8 figures, 2 tables.

Fisk, W.; Archer, K.; Chant, R.; Hekmat, D.; Offermann, F.; Pedersen, B.

1984-11-01

146

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

PubMed

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

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

2003-03-01

147

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

Microsoft Academic Search

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

Hideo Inaba; Kenji Sato

1997-01-01

148

ATS 351, Spring 2010 Water in the Atmosphere 55 points  

E-print Network

thunderstorms? c) (4 points) Why does condensation primarily occur when air is cooled? And why does warmer water cities: 1) City A has an actual vapor pressure of 6 mb and a saturation vapor pressure of 41 mb. 1 #12;2) City B has an actual vapor pressure of 6 mb also, but a saturation vapor pressure of 18 mb. c) (3

Rutledge, Steven

149

Stratospheric water inferred from Lagrangian Cold Point characteristics  

NASA Astrophysics Data System (ADS)

Total water was recently measured onboard the Geophysica high-altitude aircraft using the Jülich fluorescence hygrometer FISH during the three tropical campaigns TroCCiNOx (January-February 2005), SCOUT-O3 (November-December 2005) and AMMA (August 2006) over Southern Brazil, Northern Australia and West Africa. Trajectories are initialized at the flight locations, calculated backwards for ten days and the Lagrangian Cold Point (LCP) characteristics determined along the paths. To test whether stratospheric water values can be deduced from the temperature history of air, minimum saturation water vapor is derived from the LCP-temperature and compared to the measurements.

Ploeger, F.; Konopka, P.; Schiller, C.

2009-04-01

150

Enhanced uptake of atmospheric CO2 during freezing of seawater: A field study in Storfjorden, Svalbard  

Microsoft Academic Search

The waters of Storfjorden, a fjord in southern Svalbard, were investigated in late April 2002. The temperature was at the freezing point throughout the water column; the salinity in the top 30 m was just above 34.8, then increased nearly linearly to about 35.8 at the bottom. Nutrient and oxygen concentrations showed a minimal trend all through the water column,

Leif G. Anderson; Eva Falck; E. Peter Jones; Sara Jutterström; Jim H. Swift

2004-01-01

151

Satellite freeze forecast system  

NASA Technical Reports Server (NTRS)

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

Martsolf, J. D. (principal investigator)

1983-01-01

152

Point based hydrodynamics applied to shallow water equations  

SciTech Connect

Smoothed Particle Hydrodynamics (SPH) has proven useful for many problems of scientific interest. This report is concerned with a generalization to the SPH method which may be of value for problems such as climate modeling. The main objective of the work is to carry out the new formulation, called Point Interactive Physics and to compare results for PIP and standard finite difference techniques on a simple test problem. The basic SPH approach describes a system using a set of points. These points are not associated with a grid or mesh, as in most approaches. The individual points are each assigned a mass and move with the material velocity. Thus the original SPH method is Lagrangian. Properties of the system are expressed as sums over the sample points using a weighting function called a kernel function. For most problems, tile weighting function extends over a relatively short range, called the smoothing length. The Point Interacting Physics (PIP) approach also samples information at a set of points, and then uses kernel functions to infer physical properties everywhere. The points are not assigned fixed values of miss and they are allowed to undergo arbitrary physically reasonable motion. In this report, results will be presented for fixed points arranged irregularly over a spherical surface. Thus, this version of PIP will be applied in an Eulerian fashion. The basic reason for the Eulerian treatment is enhanced efficiency arising from the fixed geometric relationships among the points. After a brief description of the SPH and PIP methods, the PIP formulation will be compared to a normal finite difference approach for a simple shallow water advection test problem. It appears that accurate simulations can be accomplished, but that computational speed is comparable to that observed for other techniques.

Eltgroth, P.

1994-05-01

153

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

PubMed Central

Cold-hardy insects overwinter by one of two main strategies: freeze tolerance and freeze avoidance by supercooling. As a general model, many freeze-tolerant species overwinter in extreme climates, freeze above -10 degrees C via induction by ice-nucleating agents, and once frozen, can survive at temperatures of up to 40 degrees C or more below the initial freezing temperature or supercooling point (SCP). It has been assumed that the SCP of freeze-tolerant insects is unaffected by the freezing process and that the freeze-tolerant state is therefore retained in winter though successive freeze-thaw cycles of the body tissues and fluids. Studies on the freeze-tolerant larva of the hoverfly Syrphus ribesii reveal this assumption to be untrue. When a sample with a mean 'first freeze' SCP of -7.6 degrees C (range of -5 degrees C to -9.5 degrees C) were cooled, either to -10 degrees C or to their individual SCP, on five occasions, the mean SCP was significantly depressed, with some larvae subsequently freezing as low as -28 degrees C. Only larvae that froze at the same consistently high temperature above -10 degrees C were alive after being frozen five times. The wider occurrence of this phenomenon would require a fundamental reassessment of the dynamics and distinctions of the freeze-tolerant and freeze-avoiding strategies of insect overwintering. PMID:15306323

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

2004-01-01

154

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.

155

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

PubMed

An ultra-rapid freezing (URF) technology has been developed to produce high surface area powders composed of solid solutions of an active pharmaceutical ingredient (API) and a polymer stabilizer. A solution of API and polymer excipient(s) is spread on a cold solid surface to form a thin film that freezes in 50 ms to 1s. This study provides an understanding of how the solvent's physical properties and the thin film geometry influence the freezing rate and consequently the final physico-chemical properties of URF-processed powders. Theoretical calculations of heat transfer rates are shown to be in agreement with infrared images with 10ms resolution. Danazol (DAN)/polyvinylpyrrolidone (PVP) powders, produced from both acetonitrile (ACN) and tert-butanol (T-BUT) as the solvent, were amorphous with high surface areas (approximately 28-30 m2/g) and enhanced dissolution rates. However, differences in surface morphology were observed and attributed to the cooling rate (film thickness) as predicted by the model. Relative to spray-freezing processes that use liquid nitrogen, URF also offers fast heat transfer rates as a result of the intimate contact between the solution and cold solid surface, but without the complexity of cryogen evaporation (Leidenfrost effect). The ability to produce amorphous high surface area powders with submicron primary particles with a simple ultra-rapid freezing process is of practical interest in particle engineering to increase dissolution rates, and ultimately bioavailability. PMID:16987642

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

2007-01-01

156

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

157

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.

2008-09-22

158

Fuel Cell Freeze Startup and Landscape of FC Freeze Patents  

E-print Network

has a temperature below the freezing temperature of water. The supply of electric current for startup. · Use component/system models to evaluate merits of various solutions from fuel efficiency integrity · Fuel starvation (Elimination of water droplets from flow fields) · Cathode ice formation

159

Preservation of flavor in freeze dried green beans  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

160

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

EPA Science Inventory

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

161

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

162

Point-of-entry treatment of petroleum contaminated water supplies  

SciTech Connect

Contamination of individual wells in rural area from leaking petroleum storage tanks poses unique problems for regulatory agencies utilities, and potentially responsible parties. A potential solution is the use of point-of-entry (POE) treatment techniques. Results indicate POE systems using aeration followed by granular activated carbon (GAC) are a viable, cost effective, short-term solution while ground water remediation is performed or an alternate drinking water supply is secured. Selection and design of POE systems should consider variations in water usage and contaminant concentrations. Iron and manganese did not affect POE system performance at the ten sites studied. However, iron precipitation was observed and may pose problems in some POE applications. Increased concentrations of nonpurgeable dissolved organic carbon consisting primarily of methy-t-butyl ether (MTBE) and hydrophilic petroleum hydrocarbons were found in the raw waters but did not affect volatile organic chemical (VOC) removals by aeration of GAC. Microbial activity as measured by heterotrophie plate count significantly increased through four of the ten POE systems studied. Reliability of the POE systems will best be achieved by specifying top quality system components, educating POE users, and providing routine maintenance and VOC monitoring. 20 refs., 9 figs., 4 tabs.

Malley, J.P. Jr.; Eliason, P.A.; Wagler, J.L. [Univ. of New Hampshire, Durham (United States)

1993-03-01

163

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

Code of Federal Regulations, 2011 CFR

(a) A State may require a public water system to use bottled water, point-of-use devices, or point-of-entry devices as a condition of granting an exemption from the requirements of §§ 141.61 (a) and (c), and 141.62 of this...

2011-07-01

164

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 small-scale grid-based simulator that represents the heat and water budgets at and below the soil surface. It represents the energy exchange with the atmosphere, considering the radiative and turbulent fluxes, and describes the three-dimensional subsurface water flow. Furthermore, it reproduces the highly non-linear interaction of the water and energy balance during soil freezing and thawing, and describes the temporal evolution of water and energy budgets in the snow cover and their effect on soil temperature. Here, we describe 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.

2013-12-01

165

Freeze Prediction Model  

NASA Technical Reports Server (NTRS)

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

Morrow, C. T. (principal investigator)

1981-01-01

166

Tropical anvil characteristics and water vapor of the tropical tropopause layer: Impact of heterogeneous and homogeneous freezing parameterizations  

Microsoft Academic Search

Two isolated deep convective clouds (DCCs) that developed in clean-humid and polluted-dry air masses, observed during the Tropical Pacific Warm Pool International Cloud Experiment (TWP-ICE) and U.K. Aerosol and Chemical Transport in Tropical Convection (ACTIVE) campaigns, respectively, are simulated using a three-dimensional cloud-resolving model with size-resolved aerosol and cloud microphysics. We examine the impacts of different homogeneous and immersion freezing

Jiwen Fan; Jennifer M. Comstock; Mikhail Ovchinnikov; Sally A. McFarlane; Greg McFarquhar; Grant Allen

2010-01-01

167

Stability against freezing of aqueous solutions on early Mars.  

PubMed

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 273 K, 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 273 K. 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 273 K. PMID:19458717

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

2009-05-21

168

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

USGS Publications Warehouse

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

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

2006-01-01

169

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

170

VISUALIZATION OF FREEZING DAMAGE  

Microsoft Academic Search

Freeze-cleaving can be used as a direct probe to examine the ultrastructural alterations of biological material due to freezing . We examined the thesis that at least two factors, which are oppositely dependent upon cooling velocity, determine the survival of cells subjected to freezing . According to this thesis, when cells are cooled at rates exceeding a critical velocity, a

HARVEY BANK; PETER MAZUR

1973-01-01

171

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

172

JV TASK 7-FIELD APPLICATION OF THE FREEZE-THAW/EVAPORATION (FTE) PROCESS FOR THE TREATMENT OF NATURAL GAS PRODUCED WATER IN WYOMING  

SciTech Connect

The freeze-thaw/evaporation (FTE{reg_sign}) process treats oil and gas produced water so that the water can be beneficially used. The FTE{reg_sign} process is the coupling of evaporation and freeze-crystallization, and in climates where subfreezing temperatures seasonally occur, this coupling improves process economics compared to evaporation alone. An added benefit of the process is that water of a quality suited for a variety of beneficial uses is produced. The evolution, from concept to successful commercial deployment, of the FTE{reg_sign} process for the treatment of natural gas produced water has now been completed. In this document, the histories of two individual commercial deployments of the FTE{reg_sign} process are discussed. In Wyoming, as in many other states, the permitting and regulation of oil and gas produced water disposal and/or treatment facilities depend upon the legal relationship between owners of the facility and the owners of wells from which the water is produced. An ''owner-operated'' facility is regulated by the Wyoming Oil and Gas Conservation Commission (WOGCC) and is defined as an entity which only processes water which comes from the wells in fields of which they have an equity interest. However, if a facility processes water from wells in which the owners of the facility have no equity interest, the facility is considered a ''commercial'' facility and is permitted and regulated by the Wyoming Department of Environmental Quality. For this reason, of the two commercial FTE{reg_sign} process deployments discussed in this document, one is related to an ''owner-operated'' facility, and the other relates to a ''commercial'' facility. Case 1 summarizes the permitting, design, construction, operation, and performance of the FTE{reg_sign} process at an ''owner-operated'' facility located in the Jonah Field of southwestern Wyoming. This facility was originally owned by the McMurry Oil Company and was later purchased by the Alberta Energy Company (now EnCana). Case 2 summarizes the permitting, design, construction, operation, and performance at a ''commercial'' FTE{reg_sign} facility located in the Great Divide Basin of south central Wyoming. Permits required for the construction and operation of each facility are described in detail. The respective qualities of each feed water, treated water, and concentrate stream are presented along with the relative yields of treated water and concentrate at each facility. Treated water from the owner-operated facility has been beneficially used in drilling and dust abatement, and treated water from the commercial facility has been used for dust abatement, construction, and land application. The permitting requirements and evaluation of beneficial use of the water at each facility are discussed. The results of this research confirm that the FTE{reg_sign} process is economic at a commercial-scale for the treatment and disposal of natural gas produced water in Wyoming. Further, the treated water produced from the process is of a quality suitable for beneficial uses such as irrigation, drilling mix, wildlife or livestock watering, and/or dust abatement on local roads.

James A. Sorensen; John Boysen; Deidre Boysen; Tim Larson

2002-10-01

173

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

174

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

175

Water balance of Pin-Point and Flush-Flood irrigated rice  

E-print Network

is know about the water balance and water use efficiency of the Pin-Point method in comparison to the conventional Flush-Flood technique. The water balance of Pin-Point and Flush-Flood were studied during the 1994 and 1995 growing seasons in Bewmont, TX...

Roel Dellazoppa, Alvaro

2012-06-07

176

Correlation for the Vapor Pressure of Heavy Water From the Triple Point to the Critical Point  

E-print Network

H. Harveya... and Eric W. Lemmon Physical and Chemical Properties Division, National Institute for the Properties of Water and Steam IAPWS . The new formulation fits the available data within their scatter across Institute of Physics. Key words: D2O; heavy water; ITS-90; vapor pressure. Contents 1. Introduction

Magee, Joseph W.

177

Freezing in residential air-to-air heat exchangers: an experimental study  

SciTech Connect

Mechanical ventilation of residences, with heat recovery in air-to-air heat exchangers, is an increasingly common practice. When this technique of ventilation is used in cold climates, however, freezing can occur in the air-to-air heat exchanger and substantially reduce its performance. A laboratory investigation was conducted to determine the indoor and outdoor environmental conditions that lead to freezing, the impact of freezing on performance, and the effect on performance of a common freeze protection strategy based on periodic defrosts. In experiments with three different models of air-to-air heat exchangers, the temperature of the inlet cold airstream at which freezing was initiated ranged from -3/sup 0/C to -12/sup 0/C and varied with the humidity of the inlet warm airstream. Freezing caused the temperature efficiency of a cross-flow heat exchanger to decrease at a rate that ranged from 1.5 to 13.2 percentage points per hour. Small rates of decrease in efficiency (0.6 to 2.0 percentage points per hour) resulted from freezing in a counterflow exchanger. The rate of decrease in efficiency depended on the airstream temperatures and humidities, and the duration of the period of freezing. The amount of time required to defrost the heat exchanger's core was 6 to 26% of the total operating time. The average temperature efficiency for freeze-defrost cycles ranged from 48 to 64 percent in tests of the cross-flow exchanger and 70 to 82 percent in tests of the counterflow exchanger. When the frequency and duration of defrosts were nearly optimal, approximately a ten to fifteen percentage point decrease in average temperature efficiency was attributed to the freezing and required defrosts. The results suggested that the rate of performance deteriorations due to freezing can be reduced by avoiding small airflow passages that can easily be plugged with ice and by designing the exchanger so that condensed water does not drain toward the cold regions of the core.

Fisk, W.J.; Archer, K.M.; Chant, R.E.; Hekmat, D.; Offermann, F.J.; Pedersen, B.S.

1983-09-01

178

Water Rocket Seen from Educational Point of View  

NASA Astrophysics Data System (ADS)

The water rocket can be easily made of familiar materials. The water rocket flies well beyond expectations. Water rockets are widely used in educational activities for youngsters. The water rocket activities are interesting and educational for people of all ages. I will divide the contents of the water rocket activity into 3 steps and introduce representative examples in each step. I have considered the aim and the effect of each step. The 1st Step is the experience stage. The purpose of this step is to give a lot of children pleasure. In the 1st step, children are encouraged to have curiosity. It is important that the child enjoys the water rocket activity. It gets the children to think that they want to fly a water rocket. It is important to encourage children to have fun during the 1st step so that they will want to continue to the 2nd step. The 2nd Step is the research stage. The water rocket includes elements which show the children various physical phenomena. Through the water rocket activity, the child leans about real rockets. The children also learn the method of scientific experiments. Each child leans and experiences a scientific way of considering things. The water rocket is the optimal research subject for the club activities of school children. The 3rd Step is the creative stage. The child understands the principle of the mechanism. Then, the child improves a water rocket. To realize a variety of ideas, the child continues to repeat these activities in a variety of ways. In this way, the child gains a wide variety of experiences while advancing towards their goal. By using the water rocket as an educational tool we can teach children about many subjects and phenomena, many of which can be seen in daily life.

Takemae, Toshiaki

179

Stability of ?-tocopherol in freeze-dried sugar-protein-oil emulsion solids as affected by water plasticization and sugar crystallization.  

PubMed

Water plasticization of sugar-protein encapsulants may cause structural changes and decrease the stability of encapsulated compounds during storage. The retention of ?-tocopherol in freeze-dried lactose-milk protein-oil, lactose-soy protein-oil, trehalose-milk protein-oil, and trehalose-soy protein-oil systems at various water activities (a(w)) and in the presence of sugar crystallization was studied. Water sorption was determined gravimetrically. Glass transition and sugar crystallization were studied using differential scanning calorimetry and the retention of ?-tocopherol spectrophotometrically. The loss of ?-tocopherol followed lipid oxidation, but the greatest stability was found at 0 a(w) presumably because of ?-tocopherol immobilization at interfaces and consequent reduction in antioxidant activity. A considerable loss of ?-tocopherol coincided with sugar crystallization. The results showed that glassy matrices may protect encapsulated ?-tocopherol; however, its role as an antioxidant at increasing aw accelerated its loss. Sugar crystallization excluded the oil-containing ?-tocopherol from the protecting matrices and exposed it to surroundings, which decreased the stability of ?-tocopherol. PMID:22793794

Zhou, Yankun; Roos, Yrjö H

2012-08-01

180

Conditioning Water Stages From Satellite Imagery on Uncertain Data Points  

Microsoft Academic Search

Observed spatially distributed water stages with uncertainty are of considerable importance for flood modeling and management purposes but are difficult to collect in the field during a flood event. Synthetic aperture radar (SAR) remote sensing offers an inviting alternative to provide this kind of data. A straightforward technique to derive water stages from a single SAR flood image is to

Guy Schumann; Patrick Matgen; Florian Pappenberger

2008-01-01

181

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

182

Modeling aqueous solutions near the critical point of water  

Microsoft Academic Search

The author reviews the thermodynamic properties of a dilute solution near the critical point of the solvent. Two examples are discussed, a solution of a nonelectrolyte and a solution of an electrolyte. The limiting behavior of the electrolyte solutions is modeled with a Debye-Huckel term in the Helmholtz free energy. The partial molar properties, in particular the volume and isobaric

1988-01-01

183

Modelling aqueous solutions near the critical point of water  

Microsoft Academic Search

We review the thermodynamic properties of dilute solution near the critical point of the solvent. Two examples are discussed, a solution of a non-electrolyte and a solution of an electrolyte. The limiting behavior of the electrolyte solutions is modelled with a Debye-Huckel term in the Helmholtz free energy. The partial molar properties, in particular the volume and isobaric thermal expansion

Graham Morrison

1988-01-01

184

Influence of emulsifier type on freeze-thaw stability of hydrogenated palm oil-in-water emulsions  

Microsoft Academic Search

The influence of emulsifier type (Tween 20, whey protein isolate, casein) on the physical properties of 20wt% hydrogenated palm oil-in-water emulsions after crystallization of (i) the oil phase only or (ii) both the oil and water phases has been examined. Emulsion stability was assessed by differential scanning calorimetry measurements of fat destabilization after cool–heat cycles, and by measurements of mean

P Thanasukarn; R Pongsawatmanit; D. J McClements

2004-01-01

185

Freezing Combination Main Dishes  

E-print Network

Making your own frozen prepared foods can be economical. You can cook enough for several meals with little extra effort when you have the time. For best results, remember that freezing maintains, but does not improve, quality. Use only fresh, high-quality food ingredients. Underripe fruits and vegetables lack flavor, and overripe ones are flat and tough, or soft and mushy after freezing. Meat or poultry that is tender before freezing will stay tender after freezing if it is properly prepared, packaged, frozen, and stored. Cleanliness Observe strict cleanliness in preparing food for the home freezer. Freezer temperatures of 0 degrees F or below do not kill bacteria in food; they simply stop bacteria from multiplying. After the frozen food is thawed, bacteria will grow and multiply again. Strict cleanliness keeps the number of bacteria at a minimum before foods are frozen. Foods to Use and Foods to Avoid You may use many of your own favorite recipes for freezing. Prepare the food in the usual way. Cook thoroughly but do not overcook. There may be further cooking when reheated. Foods That Freeze Well • Cooked chicken or turkey in casseroles. • Stews and goulashes made with beef, lamb, pork, or veal. Most vegetables used in these combination dishes, such as peas, carrots, celery, or small quantities of onion also freeze well. However, potatoes may not be satisfactory. • Baked meat loaf. • Cooked dried beans, such as bean soup and baked beans. Because freezing softens beans somewhat, cook until barely tender for best quality. Limit storage time to two weeks if seasoned with ham or bacon. Foods That Do Not Freeze Well The flavor and texture of some foods become poor during freezing. Avoid using these foods. • Cooked egg white toughens. • Mature potatoes which tend to disintegrate, become watery, or darken. New potatoes are better. • Fried foods tend to lose crispness and become soggy. • Avoid freezing cured meats; salt hastens rancidity. • Fresh salad greens, raw tomatoes, raw apples and grapes become soft, soggy, and mushy.

unknown authors

186

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

E-print Network

), This hypothesis was tested by Dittmar (1884) when he perform d extensive analyses on seventy seven sea- water samples collected from all oceans and all depths by the Challenger expedition. His findings led to the concept that the ratios of the various ions...), This hypothesis was tested by Dittmar (1884) when he perform d extensive analyses on seventy seven sea- water samples collected from all oceans and all depths by the Challenger expedition. His findings led to the concept that the ratios of the various ions...

Burkhalter, Albert Charles

2012-06-07

187

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

188

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

189

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

PubMed

A spray freezing into liquid (SFL) particle engineering technology has been developed to produce micronized powders to enhance the dissolution of poorly water soluble active pharmaceutical ingredients (APIs). Previously, a tetrahydrofuran (THF)/water co-solvent was used as the solution source in the SFL process. In the present study, an organic system was developed to further enhance the properties of particles produced by SFL. The influence of solution type (e.g. organic versus organic/water) on the physicochemical properties of SFL powders was investigated and compared. The physicochemical properties of SFL carbamazepine (CBZ)/poloxamer 407/PVP K15 (2:1:1 ratio) powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size distribution, surface area analysis, contact angle measurement, Karl-Fisher (KF) titration, gas chromatography (GC) analysis, HPLC analysis, and dissolution testing. The CBZ loading in the feed solution of the SFL acetonitrile system was 2.2% (w/w), which was greater than 0.22% (w/w) loading of the THF/water co-solvent system. XRD results indicated CBZ was amorphous in SFL powders produced by either system. SEM micrographs indicated that SFL powders from acetonitrile appeared less porous with a smaller primary particle size than particles from the co-solvent. The M50 (50% cumulative percent undersize) of micronized powder from the SFL acetonitrile system and the THF/water co-solvent system with 0.22% CBZ loading were 680nm and 7.06microm, respectively. The surface area of SFL powders from the acetonitrile and co-solvent systems were 12.89 and 13.31m(2)/g, respectively. The contact angle of the SFL powders against purified water was about 35 degrees for both systems. The SFL powders from both systems exhibited similar and significantly enhanced dissolution rates compared to the bulk CBZ. Acetonitrile was an effective alternative solvent to THF/water co-solvent for use with the SFL micronization process to produce free flowing particles containing CBZ with significantly enhanced wetting and dissolution properties. PMID:14592695

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

2003-11-01

190

Optimization of the secondary drying step in freeze drying using TDLAS technology.  

PubMed

The secondary drying phase in freeze drying is mostly developed on a trial-and-error basis due to the lack of appropriate noninvasive process analyzers. This study describes for the first time the application of Tunable Diode Laser Absorption Spectroscopy, a spectroscopic and noninvasive sensor for monitoring secondary drying in laboratory-scale freeze drying with the overall purpose of targeting intermediate moisture contents in the product. Bovine serum albumin/sucrose mixtures were used as a model system to imitate high concentrated antibody formulations. First, the rate of water desorption during secondary drying at constant product temperatures (-22 °C, -10 °C, and 0 °C) was investigated for three different shelf temperatures. Residual moisture contents of sampled vials were determined by Karl Fischer titration. An equilibration step was implemented to ensure homogeneous distribution of moisture (within 1%) in all vials. The residual moisture revealed a linear relationship to the water desorption rate for different temperatures, allowing the evaluation of an anchor point from noninvasive flow rate measurements without removal of samples from the freeze dryer. The accuracy of mass flow integration from this anchor point was found to be about 0.5%. In a second step, the concept was successfully tested in a confirmation experiment. Here, good agreement was found for the initial moisture content (anchor point) and the subsequent monitoring and targeting of intermediate moisture contents. The present approach for monitoring secondary drying indicated great potential to find wider application in sterile operations on production scale in pharmaceutical freeze drying. PMID:21359604

Schneid, Stefan C; Gieseler, Henning; Kessler, William J; Luthra, Suman A; Pikal, Michael J

2011-03-01

191

Freezing of Xylem Sap Without Cavitation  

PubMed Central

Freezing of stem sections and entire twigs of hemlock (Tsuga canadensis) has been demonstrated to occur without increasing the resistance to the movement of water through the frozen part after rewarming. This was interpreted to mean that freezing did not produce cavitation in the xylem sap even though A) the sap was unquestionably frozen; B) it contained dissolved gases; and C) it was under tension before freezing and after. Freezing stem sections of some other evergreen gymnosperms during the summer again produced no evidence for cavitation of the xylem sap. On the other hand, freezing stem sections of some angiosperms invariably increased the resistance to sap flow leading to wilting and death in a few hours when the sap tension was at normal daytime values at the time of freezing. These results were interpreted to mean that the bordered pits on the tracheids of gymnosperms function to isolate the freezing sap in each tracheid so that the expansion of water upon freezing not only eliminates any existing tension but also develops positive pressure in the sap. Dissolved gases frozen out of solution may then be redissolved under this positive pressure as melting occurs. As the bubbles are reduced in size by this ice pressure developed in an isolated tracheid, further pressure is applied by the surface tension of the water against air. If the bubbles are redissolved or are reduced to sufficient small size by the time the tension returns to the sap as the last ice crystals melt, then the internal pressure from surface tension in any existing small bubbles may exceed the hydrostatic tension of the melted sap and the bubbles cannot expand and will continue to dissolve. PMID:16656485

Hammel, H. T.

1967-01-01

192

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

PubMed

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

Davis, D J; Lee, R E

2001-12-01

193

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

PubMed

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

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

2013-07-15

194

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

E-print Network

@ipst.umd.edu #12;1 Abstract A new fixed-point charge potential model for water has been developed, targeting interactions in water, an intermolecular potential model valid over a broad range of densities and temperatures and their successful description of the structure of liquid water at near-ambient conditions. A Lennard-Jones potential

195

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

EPA Science Inventory

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

196

Evaluating the contribution of point and non-point sources of nitrogen pollution in stream water in a rural area of Central Hokkaido, Japan  

Microsoft Academic Search

There is an increasing concern about nitrogen (N) pollution of surface water for which agricultural activities can be identified as non-point sources. Drainage from manure storage sites in large-scale livestock husbandry operations and drainage from landfill sites are considered to be point sources of N pollution that severely affect the quality of stream water. We evaluated the contribution of point

Toshiyuki Nagumo; Krishna Prasad Woli; Ryusuke Hatano

2004-01-01

197

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

198

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

PubMed

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

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

2013-02-01

199

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

200

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

2012-06-07

201

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

202

Glycerol loss to water exceeds glycerol catabolism via glycerol kinase in freeze-resistant rainbow smelt (Osmerus mordax).  

PubMed

Rainbow smelt accumulate high amounts of glycerol in winter. In smelt, there is a predictable profile of plasma glycerol levels that starts to increase in November (<5 ?mol/ml), peaks in mid-February (>200 ?mol/ml), and thereafter decreases to reach the initial levels in the beginning of May. The aim of this study was to investigate the respective role of the two main mechanisms that might be involved in glycerol clearance from mid-February: 1) breakdown of glycerol to glycerol-3-phosphate through the action of the glycerol kinase (GK) and 2) direct loss toward the environment. Over the entire glycerol cycle, loss to water represents a daily loss of ?10% of the total glycerol content of fish. GK activities were very low in all tissues investigated and likely have a minor quantitative role in the glycerol cycle. These results suggest that glycerol levels are dictated by the rate of glycerol synthesis (accelerated and deactivated during the accumulation and decrease stages, respectively). Although not important in glycerol clearance, GK in liver might have an important metabolic function for other purposes, such as gluconeogenesis, as evidenced by the significant increase of activity at the end of the cycle. PMID:21178128

Ditlecadet, Delphine; Short, Connie E; Driedzic, William R

2011-03-01

203

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

204

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

205

Freeze-Thaw  

Microsoft Academic Search

Although attempting to consider the impact of freeze-thaw, the monitoring of associated thermal conditions must, effectively,\\u000a be context free. This is important for several reasons. First, although freeze-thaw is being evaluated, data must be of a\\u000a nature that also allows determination of the spatial and temporal role of other processes. Second, by being ‘holistic’ rather\\u000a than (assumed) ‘specific’ in character

Kevin Hall

206

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...

207

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...

208

Peculiar points in the phase diagram of the water-alcohol solutions  

E-print Network

The work is devoted to the investigation of nontrivial behavior of dilute water-alcohol solutions. The temperature and concentration dependencies of the contraction for aqueous solutions of ethanol and methanol are analyzed. The existence of a specific point, the so-called peculiar point, was established. It is shown that water-alcohol solutions of different types obey the principle of corresponding states if temperature and volume fraction are used as principal coordinates. In this case, the concentration of the peculiar point for different solutions is close to x_{\

Chechko, V E; Malomuzh, M P

2013-01-01

209

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

210

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

211

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

NASA Astrophysics Data System (ADS)

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

Möhlmann, D.

2007-08-01

212

Transmembrane ion distribution during recovery from freezing in the woolly bear caterpillar Pyrrharctia isabella (Lepidoptera: Arctiidae).  

PubMed

During extracellular freezing, solutes in the haemolymph are concentrated, resulting in osmotic dehydration of the cells, which must be reversed upon thawing. Here, we used freeze tolerant Pyrrharctia isabella (Lepidoptera: Arctiidae) larvae to examine the processes of ion redistribution after thawing. To investigate the effect of the intensity of cold exposure on ion redistribution after thawing, we exposed caterpillars to -14°C, -20°C or -30°C for 35h. To investigate the effect of duration of cold exposure on ion redistribution after thawing, we exposed the caterpillars to -14°C for up to 6 weeks while sampling several time points. The concentrations of Na(+), K(+), Mg(2+) and Ca(2+) were measured after thawing in the haemolymph, fat body, muscle, midgut tissue and hindgut tissue. Being frozen for long durations (>3 weeks) or at low temperatures (-30°C) both result in 100% mortality, although different ions and tissues appear to be affected by each treatment. Both water distribution and ion content changes were detected after thawing, with the largest effects seen in the fat body and midgut tissue. Magnesium homeostasis appears to be vital for post-freeze survival in these larvae. The movement of ions during thawing lagged behind the movement of water, and ion homeostasis was not restored within the same time frame as water homeostasis. Failure to regain ion homeostasis after thawing is therefore implicated in mortality of freeze tolerant insects. PMID:21575641

Boardman, Leigh; Terblanche, John S; Sinclair, Brent J

2011-08-01

213

Time series analysis of soil freeze-thaw processes in Indiana  

E-print Network

1 Time series analysis of soil freeze-thaw processes in Indiana Tushar Sinha and Keith A. Cherkauer Test Data Quality Control Extreme temperature Data Processing based on Water Year Freeze-Thaw Cycles

Cherkauer, Keith

214

Investigation of PEG crystallization in frozen PEG-sucrose-water solutions. I. Characterization of the nonequilibrium behavior during freeze-thawing.  

PubMed

Our objective was to characterize the nonequilibrium thermal behavior of frozen aqueous solutions containing PEG and sucrose. Aqueous solutions of (i) sucrose (10%, w/v) with different concentrations of PEG (1-20%, w/v), and (ii) PEG (10%, w/v) with different concentrations of sucrose (2-20%, w/v), were cooled to -70 degrees C at 5 degrees C/min and heated to 25 degrees C at 2 degrees C/min in a differential scanning calorimeter. Annealing was performed at temperatures ranging from -50 to -20 degrees C for 2 or 6 h. Similar experiments were also performed in the low-temperature stage of a powder X-ray diffractometer. A limited number of additional DSC experiments were performed wherein the samples were cooled to -100 degrees C. In unannealed systems with a fixed sucrose concentration (10%, w/v), the T'g decreased from -35 to -48 degrees C when PEG concentration was increased from 1% to 20% (w/v). On annealing at -25 degrees C, PEG crystallized. This was evident from the increase in T'g and the appearance of a secondary melting endotherm in the DSC. Low-temperature XRD provided direct evidence of PEG crystallization. Annealing at temperatures water system, reflecting progressive PEG crystallization. A second glass transition at approximately -65 degrees C was evident in unannealed systems [10%, w/v sucrose and 10 (or 20%), w/v PEG] cooled to -100 degrees C. Investigation of the nonequilibrium behavior of frozen PEG-sucrose-water ternary system revealed phase separation in the freeze-concentrate. Annealing facilitated PEG crystallization. PMID:20091827

Bhatnagar, Bakul S; Martin, Susan M; Teagarden, Dirk L; Shalaev, Evgenyi Y; Suryanarayanan, Raj

2010-06-01

215

Costs and water quality effects of controlling point and nonpoint pollution sources  

SciTech Connect

Costs and water quality effects of controlling point and nonpoint pollution sources are compared for the DuPage River basin in northern Illinois. Costs are estimated for effluent standards for municipal wastewater treatment plants and for the alternative, controlling runoff from nonpoint sources such as streets, agricultural lands, and forests. A dynamic water-quality/hydrology simulation model is used to determine water quality effects of various treatment plant standards and nonpoint-source controls. Costs and water quality data are combined, and the point-source and nonpoint-source plans are compared on a cost-effectiveness basis. Nonpoint-source controls are found to be more cost-effective than stricter control of pollutants from point sources.

Macal, C.M.; Broomfield, B.J.

1980-01-01

216

Phase separation during freezing upon warming of aqueous solutions  

NASA Astrophysics Data System (ADS)

Using differential scanning calorimetry, we show that the addition of solute(s) to emulsified water lowers the freezing temperature to <231 K, the homogeneous nucleation temperature of pure bulk water, or even completely suppresses freezing. In the latter case, freezing upon warming occurs above TX ? 150 K and leads to a phase separation into pure ice and a freeze-concentrated solution (FCS) which crystallizes upon further warming. We also show that emulsified 20-21.5 wt. % HCl solutions and the FCS of HCl/H2O solutions transform to glass at Tg ? 127-128 K, i.e., lower than Tg ? 136 K of water. We suggest that water nanodrops adsorbed on fumed silica resemble bulk water more than water confined in nanoscaled confinement and also more than nanoscaled water domains in aqueous solution.

Bogdan, A.; Loerting, T.

2014-11-01

217

Phase separation during freezing upon warming of aqueous solutions.  

PubMed

Using differential scanning calorimetry, we show that the addition of solute(s) to emulsified water lowers the freezing temperature to <231 K, the homogeneous nucleation temperature of pure bulk water, or even completely suppresses freezing. In the latter case, freezing upon warming occurs above TX ? 150 K and leads to a phase separation into pure ice and a freeze-concentrated solution (FCS) which crystallizes upon further warming. We also show that emulsified 20-21.5 wt. % HCl solutions and the FCS of HCl/H2O solutions transform to glass at Tg ? 127-128 K, i.e., lower than Tg ? 136 K of water. We suggest that water nanodrops adsorbed on fumed silica resemble bulk water more than water confined in nanoscaled confinement and also more than nanoscaled water domains in aqueous solution. PMID:25399198

Bogdan, A; Loerting, T

2014-11-14

218

Tandem High-pressure Freezing and Quick Freeze Substitution of Plant Tissues for Transmission Electron Microscopy.  

PubMed

Since the 1940s transmission electron microscopy (TEM) has been providing biologists with ultra-high resolution images of biological materials. Yet, because of laborious and time-consuming protocols that also demand experience in preparation of artifact-free samples, TEM is not considered a user-friendly technique. Traditional sample preparation for TEM used chemical fixatives to preserve cellular structures. High-pressure freezing is the cryofixation of biological samples under high pressures to produce very fast cooling rates, thereby restricting ice formation, which is detrimental to the integrity of cellular ultrastructure. High-pressure freezing and freeze substitution are currently the methods of choice for producing the highest quality morphology in resin sections for TEM. These methods minimize the artifacts normally associated with conventional processing for TEM of thin sections. After cryofixation the frozen water in the sample is replaced with liquid organic solvent at low temperatures, a process called freeze substitution. Freeze substitution is typically carried out over several days in dedicated, costly equipment. A recent innovation allows the process to be completed in three hours, instead of the usual two days. This is typically followed by several more days of sample preparation that includes infiltration and embedding in epoxy resins before sectioning. Here we present a protocol combining high-pressure freezing and quick freeze substitution that enables plant sample fixation to be accomplished within hours. The protocol can readily be adapted for working with other tissues or organisms. Plant tissues are of special concern because of the presence of aerated spaces and water-filled vacuoles that impede ice-free freezing of water. In addition, the process of chemical fixation is especially long in plants due to cell walls impeding the penetration of the chemicals to deep within the tissues. Plant tissues are therefore particularly challenging, but this protocol is reliable and produces samples of the highest quality. PMID:25350384

Bobik, Krzysztof; Dunlap, John R; Burch-Smith, Tessa M

2014-01-01

219

Ultrasound-Assisted Freezing  

NASA Astrophysics Data System (ADS)

Freezing is a well-known preservation method widely used in the food industry. The advantages of freezing are to a certain degree counterbalanced by the risk of damage caused by the formation and size of ice crystals. Over recent years new approaches have been developed to improve and control the crystallization process, and among these approaches sonocrystallization has proved to be very useful, since it can enhance both the nucleation rate and the crystal growth rate. Although ultrasound has been successfully used for many years in the evaluation of various aspects of foods and in medical applications, the use of power ultrasound to directly improve processes and products is less popular in food manufacturing. Foodstuffs are very complex materials, and research is needed in order to define the specific sound parameters that aid the freezing process and that can later be used for the scale-up and production of commercial frozen food products.

Delgado, A. E.; Sun, Da-Wen

220

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

221

ORIGINAL PAPER Effect of freezing-thawing on nitrogen mineralization  

E-print Network

ORIGINAL PAPER Effect of freezing-thawing on nitrogen mineralization in vegetation soils of four the effect of freezing-thawing on nitrogen (N) mineralization of four vegetation soils from typical . Soil nitrogen mineralization . Soil water content . Temperate forest . Changbai Mountain 1 Introduction

Boyer, Edmond

222

Freezing of Barley Studied by Infrared Video Thermography  

Microsoft Academic Search

Freezing of barley (Hordeum vulgare), Hordeum murinum, and Holcus lanatus was studied using infrared video thermography. In the field, ice could enter H. lanatus leaves through hydathodes. In laboratory tests with barley, initially 0.4% of the leaf water froze, spreading in alternate strips of high and low freezing intensity longitudinally at 1 to 4 cm s21, and simultaneously spreading laterally

Roger S. Pearce; Michael P. Fuller

2001-01-01

223

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

224

Freeze resistance in rainbow smelt (Osmerus mordax): seasonal pattern of glycerol and antifreeze protein levels and liver enzyme activity associated with glycerol production.  

PubMed

Rainbow smelt (Osmerus mordax) inhabit inshore waters along the North American Atlantic coast. During the winter, these waters are frequently ice covered and can reach temperatures as low as -1.9 degrees C. To prevent freezing, smelt accumulate high levels of glycerol, which lower the freezing point via colligative means, and antifreeze proteins (AFP). The up-regulation of the antifreeze response (both glycerol and AFP) occurs in early fall, when water temperatures are 5 degrees -6 degrees C. The accumulation of glycerol appears to be the main mechanism of freeze resistance in smelt because it contributes more to the lowering of the body's freezing point than the activity of the AFP (0.5 degrees C vs. 0.25 degrees C for glycerol and AFP, respectively) at a water temperature of -1.5 degrees C. Moreover, AFP in smelt appears to be a safeguard mechanism to prevent freezing when glycerol levels are low. Significant increases in activities of the liver enzymes glycerol 3-phosphate dehydrogenase (GPDH), alanine aminotransferase (AlaAT), and phosphoenolpyruvate carboxykinase (PEPCK) during the initiation of glycerol production and significant correlations between enzyme activities and plasma glycerol levels suggest that these enzymes are closely associated with the synthesis and maintenance of elevated glycerol levels for use as an antifreeze. These findings add further support to the concept that carbon for glycerol is derived from amino acids. PMID:15286915

Lewis, Johanne M; Ewart, K Vanya; Driedzic, William R

2004-01-01

225

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

226

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

227

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

228

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

229

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

...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

230

Freeze-Dehydration by Microwave Energy.  

National Technical Information Service (NTIS)

A general unsteady state analysis is used to derive a mathematical model of the freeze-drying process using microwave heating. The temperature and water vapor concentration profiles inside the material being dried are calculated. The model is applied to s...

P. R. F. Peltre

1974-01-01

231

Determination of disulfoton in surface water samples by cloud-point extraction and gas chromatography  

Microsoft Academic Search

This article proposes an alternative method, using cloud-point extraction and gas chromatography, for extraction and determination of disulfoton in water samples. For cloud-point extraction, the nonionic surfactant Triton X-114 was used. Before gas chromatography, a cleanup stage for surfactant removal from the extracts was optimized. Cleanup used two columns, in series, containing silica gel and Florisil, with methanol:hexane (1?:?1) as

Anizio M. Faria; Raquel P. Dardengo; Claudio F. Lima; Antonio A. Neves; Maria Eliana L. R. Queiroz

2007-01-01

232

Animal Anti-Freeze  

NSDL National Science Digital Library

In this outdoor winter activity, learners search for and create hibernation sites that will protect gelatin "animals" from freezing. Learners come to understand that hibernating animals need to take care in selecting a sleeping spot that will provide protection from the winter cold.

Science, Lawrence H.

1982-01-01

233

Freeze Branding Horses  

E-print Network

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

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

2001-06-29

234

Cryogenic freezing system  

SciTech Connect

The operation of a prior art freezer installation for freezing food can be improved by: providing air curtains at the doors of the freezer; using a pulse bag filter for separating ice from the air leaving the freezer; and ensuring that the air leaving the freezer is colder than -800 F.

Prentice, A.L.

1982-03-02

235

Freezing Index Maps of Maine.  

National Technical Information Service (NTIS)

The depth of frost penetration can be calculated by means of the modified Berggren formula whose dependent variables are various soils characteristics and air freezing index. Because the last comprehensive study of the distribution of freezing indexes in ...

N. Bigelow

1969-01-01

236

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

237

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

2006-03-21

238

Membranes and MEAs at Freezing Temperatures Thomas A. Zawodzinski, Jr.  

E-print Network

' of Water in Proton Conductors ? Freezing (bulk), bound freezable, bound non freezable water states claimedControlling Phenomena High ( > 0.04 S/cm)Low ( Proton Conductivity Grotthuss (hopping) Vehicular (water for conduction at very low water contents associated with tight binding of water and protons

239

Mathematical Modeling and Numerical Simulation of Freezing Processes of a Supercooled Melt under  

E-print Network

of melted iron or alloys, the freezing of water, the cooling of food and tissue, the latent heat thermalMathematical Modeling and Numerical Simulation of Freezing Processes of a Supercooled Melt under In this paper, we derive a model for the two­phase freezing process of supercooled fluids. Especially, we take

Bebendorf, Mario

240

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

241

A water quality monitoring network design methodology for the selection of critical sampling points: Part II  

Microsoft Academic Search

In order to resolve the spatial component of the design of a water quality monitoring network, a methodology has been developed to identify the critical sampling locations within a watershed. This methodology, called Critical Sampling Points (CSP), focuses on the contaminant total phosphorus (TP), and is applicable to small, predominantly agricultural-forested watersheds. The CSP methodology was translated into a model,

R. O. Strobl; P. D. Robillard; R. L. Day; R. D. Shannon; A. J. McDonnell

2006-01-01

242

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

NASA Astrophysics Data System (ADS)

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

White, D. R.

2004-01-01

243

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...

244

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

245

Glass Transition in Biomolecules and the Liquid-Liquid Critical Point of Water Pradeep Kumar,1  

E-print Network

, sometimes called a ``protein glass transition,'' occurs at the temperature of dynamic crossoverGlass Transition in Biomolecules and the Liquid-Liquid Critical Point of Water Pradeep Kumar,1 Z and the temperature derivative of the orientational order parameter. We relate these findings to the hypothesis

Stanley, H. Eugene

246

Turkey Point tritium. Progress report. [Monitoring in atmosphere and cooling water  

Microsoft Academic Search

In 1972-73 the Florida Power and Light Company (FPL) began operation of two nuclear reactors at Turkey Point on lower Biscayne Bay. One radioactive by-product resulting from the operation of the nuclear reactors, tritium, provides a unique opportunity to study transport and exchange processes on a local scale. Since the isotope in the form of water is not removed from

H. G. Ostlund; H. G. Dorsey

1976-01-01

247

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

PubMed

Inactivation capacity of E. coli (strain ATCC 15597) in water by natural freezing was examined via two freezing methods: spray freezing and freezing in a freezer. The effect of freezing temperature (-5, -15 and -35 degrees C), storage time, freeze-thaw cycles on the survival of the test organism were investigated. In addition, the number of cells injured by the freezing process was also examined by using different growth media. The bacteria frozen at the warmer temperature (-5 degrees C) was most sensitive to storage and freeze-thaw cycles as compared to those frozen at -15 and -35 degrees C. In general, greater inactivation efficiencies were achieved under longer storage time and warmer freezing temperature conditions. Freezing and thawing caused cell injury. More cells were injured when frozen at -15 degrees C. The percentage of cells injured decreased as freeze-thaw cycles increased. The spray-freezing process was found more effective in killing the cells. On average, the log reduction rate for the spray ice with two-day storage time was about 4 log units higher than those without any storage after freezing. The results indicated that the natural freezing processes are not only cost-effective techniques for chemical and physical contaminant removal from wastewater or enhancing sludge dewaterability in cold regions but also effective in reducing E. coli concentration. PMID:16740289

Gao, W; Smith, D W; Li, Y

2006-07-01

248

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

249

A point focusing collector for an integrated water/power complex  

NASA Astrophysics Data System (ADS)

A point focusing parabolic dish was developed in order to deliver process heat and as a solar collector for small solar thermal power stations. The utilization potential of the point focusing parabolic dish was identified and its main design parameters are summarized. The utilization of the collector as primary energy source in a food/water/power complex was tested. In its present configuration, the system is capable of delivering process heat for the temperature range from 150 to 500 C. This point focusing parabolic dish is identified as the most promising solar collector for small solar thermal power stations. Fifty-six dishes were assembled in a 100 kW (electric)/500 kW (thermal) food/water/power complex, which is in operation in the Kuwait desert. The dominating factors for cost reduction are discussed.

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

250

Nanoscale Dynamics of Phase Flipping in Water near its Hypothesized Liquid-Liquid Critical Point  

PubMed Central

One hypothesized explanation for water's anomalies imagines the existence of a liquid-liquid (LL) phase transition line separating two liquid phases and terminating at a LL critical point. We simulate the classic ST2 model of water for times up to 1000?ns and system size up to N = 729. We find that for state points near the LL transition line, the entire system flips rapidly between liquid states of high and low density. Our finite-size scaling analysis accurately locates both the LL transition line and its associated LL critical point. We test the stability of the two liquids with respect to the crystal and find that of the 350 systems simulated, only 3 of them crystallize and these 3 for the relatively small system size N = 343 while for all other simulations the incipient crystallites vanish on a time scales smaller than ? 100?ns. PMID:22761987

Kesselring, T. A.; Franzese, G.; Buldyrev, S. V.; Herrmann, H. J.; Stanley, H. E.

2012-01-01

251

Point-of-entry drinking-water treatment systems for Superfund applications  

SciTech Connect

The U.S. Environmental Protection Agency (EPA) and State Superfund agencies need a technical manual to assist their personnel in the selection of an effective drinking-water treatment system for individual households in areas where the drinking water has been adversely affected by Superfund site contaminants and no other alternative water supply is available or feasible. Commercially available water treatment systems for individual households are of two basic types: point-of-use (POU) and point-of-entry (POE). A POU device consists of equipment applied to selected water taps to reduce contaminants at each tap. A POE device consists of equipment to reduce the contaminants in the water distributed throughout the entire structure of a house. The study was initiated to collect monitoring, operation and maintenance, performance, and design data on existing Superfund POE water-treatment systems. Evaluation of the collected data showed that the existing data are not sufficient for the preparation of a technical assistance document to meet the objectives of EPA and State Superfund personnel.

Chambers, C.D.; Janszen, T.A.

1989-06-01

252

Deliquesence and freezing of stratospheric aerosol observed by balloonborne backscattersondes  

SciTech Connect

Stratospheric sulfate aerosols, originating from the Mt. Pinatubo volcanic eruption, have been observed during three winters in the Arctic by balloonborne backscattersondes. A measured color index, defined as the quotient between the aerosol backscatter ratios at wavelengths 940 and 480 nm, provides information of the size of the observed particles. The effects of liquid particle growth, by water vapor uptake, clearly show up as changes in the color index, whereas measurements on other days indicate the particles to be frozen. Air parcel trajectories have been calculated, providing the temperature history of the observed particles. Evidences appear of a temperature hysteresis in the freezing and melting cycle of the aerosol, indicating melting temperatures around 215-220 K in good agreement with laboratory measurements, and freezing of the particles within less than 5 K above the ice frost point. The changes in color index of the liquid particles are in good agreement with predictions from theoretical model calculations of growth by water vapor uptake. 13 refs., 5 figs., 1 tab.

Larsen, N.; Knudsen, B. [Danish Meterological Institute, Copenhagen (Denmark)] [Danish Meterological Institute, Copenhagen (Denmark); Rosen, J.M. [Univ. of Wyoming, Laramie, WY (United States)] [and others] [Univ. of Wyoming, Laramie, WY (United States); and others

1995-05-15

253

Novel methods for rapid freezing and thawing of foods – a review  

Microsoft Academic Search

This paper reviews new developments in methods of freezing (high-pressure freezing, dehydrofreezing and applications of antifreeze protein and ice nucleation protein) and thawing (high-pressure and microwave thawing, ohmic thawing and acoustic thawing) for foods. With a good understanding of the solid–liquid phase diagram of water, the effects of pressure on food freezing–thawing cycles are highlighted. High-pressure freezing promotes uniform and

Bing Li; Da-Wen Sun

2002-01-01

254

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

255

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

E-print Network

the findings of a 12-week effectiveness study of point-of-use water treatment with a flocculant, point-of-use water treatment with the flocculant­disinfectant plus improved storage reduced diarrhoea, household water treatment, flocculant­disinfectant, Liberia, diarrhoea Introduction Communicable diseases

Scharfstein, Daniel

256

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

257

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

258

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...

259

Inactivation of Kudoa septempunctata in Olive Flounder Meat by Liquid Freezing.  

PubMed

Kudoa septempunctata in olive flounder meat was inactivated using 3 distinct freezing methods? liquid freezing for 5 min, air blast freezing at ?30? for 5 h, and ?80? for 1 h. The fracture curve of olive flounder meat subjected to liquid freezing resembled that of meat stored at 4?, indicating that the structure of olive flounder muscle was well preserved. In contrast, air blast freezing induced the disappearance of the fracture point in the fracture curve, indicating that there was deterioration in the meat quality. Liquid freezing preserved the transparency of olive flounder meat to the same degree as that of meat stored at 4°C. However, air blast freezing induced meat cloudiness. These results indicate that liquid freezing can be used for K. septempunctata inactivation without affecting the meat quality. PMID:25252645

Ohnishi, Takahiro; Akuzawa, Sayuri; Furusawa, Hiroko; Yoshinari, Tomoya; Kamata, Yoichi; Sugita-Konishi, Yoshiko

2014-01-01

260

Atmosphere-ground modelling of freeze and thaw processes in permafrost regions  

NASA Astrophysics Data System (ADS)

The aim of this proposed project is to realistically simulate the water and energy exchange processes between atmosphere and ground in permafrost regions by using a coupled soil-atmosphere model system. The project will be focused on freezing and thawing processes of the ground, in particular permafrost degradation processes such as changes in the active layer thickness. The coupled model system consists of the non-hydrostatic mesoscale model KAMM (Karlsruhe Atmospheric Mesoscale Model) and the soil vegetation atmosphere transport (SVAT) model VEG3D, recently extended to incorporate explicit treatment of the snow cover evolution. In order to simulate the evolution of frozen ground and to address permafrost specific processes, the SVAT model has to be extended to incorporate the occurrence of frozen water. Parameterisations for processes associated with freezing and thawing, such as freezing point depression and changes in unfrozen water circulation will be included. Model validation will be performed using data sets from different permafrost sites, including monitoring data of ground temperature, soil water content and standard meteorological parameters. Model simulations will be conducted on different temporal and spatial scales, especially for comparative analyses of similar atmospheric episodes in different Arctic and Alpine regions.

Hauck, C.; Kneisel, C.; Kottmeier, C.

2003-04-01

261

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

262

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

Code of Federal Regulations, 2011 CFR

... 2011-07-01 2011-07-01 false Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...RESTRICTED AREA REGULATIONS § 334.412 Albemarle Sound, Pamlico Sound, Harvey Point and adjacent...

2011-07-01

263

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

Code of Federal Regulations, 2012 CFR

... 2012-07-01 2012-07-01 false Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...RESTRICTED AREA REGULATIONS § 334.412 Albemarle Sound, Pamlico Sound, Harvey Point and adjacent...

2012-07-01

264

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

Code of Federal Regulations, 2010 CFR

... 2010-07-01 2010-07-01 false Albemarle Sound, Pamlico Sound, Harvey Point and adjacent waters, NC; restricted...RESTRICTED AREA REGULATIONS § 334.412 Albemarle Sound, Pamlico Sound, Harvey Point and adjacent...

2010-07-01

265

Kriging water levels with a regional-linear and point-logarithmic drift.  

PubMed

Ground water levels measured in the vicinity of pumping wells are kriged using a regional-linear and point-logarithmic drift, the latter derived from the approximation to the Theis equation for drawdown in response to a pumping well. Kriging is widely used throughout the hydrogeologic discipline, most commonly as the preferred method for constructing gridded hydrogeologic datasets suitable for contouring. Residuals arising from using the most common (linear) drift to krige water levels in the vicinity of extraction wells often indicate large local departures from the linear drift, which correlate with areas of drawdown. The combined regional-linear and point-logarithmic drift accounts for these drawdowns using a logarithmic approximation for the curvature of the potentiometric surface. The drift model approximates the principal physical processes that govern ground water flow and ultimately govern the autocorrelation of ground water elevation data. This approach produces maps of contoured water levels that more realistically represent physical conditions and allow for improved interpretation of measured water-level data by including features and information known to be present. Additional benefits include an improved estimate of the regional (background) hydraulic gradient and generation of an approximately flow-conserved grid suitable for two-dimensional particle tracking. PMID:11916123

Tonkin, Matthew J; Larson, Steven P

2002-01-01

266

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.

267

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

PubMed

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

Fujioka, R S

2001-01-01

268

Study on Melting Process of Frozen Silica Gel Including Water  

NASA Astrophysics Data System (ADS)

In this study, the thermal characteristics of water including an adsorbent were analyzed by a differential scanning calorimeter, DSC, in the temperature range from -20 to 20°C, and the heat generation by adsorbing the water was measured by a calorific meter, in order to examine the effects of the adsorption characteristics of the adsorbent. As a result, it was found that the surface adsorption water in a micro pore of nanometer order did not freeze and the capillary water could freeze. The capillary water showed the lower melting point than the free water. The latent heat of the capillary water decreased with increasing the adsorption heat of adsorbent.

Hirasawa, Yoshio; Mizaki, Futoshi; Takegoshi, Eisyun

269

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

270

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

271

Condensation and freezing of droplets on superhydrophobic surfaces.  

PubMed

Superhydrophobic coatings are reported as promising candidates for anti-icing applications. Various studies have shown that as well as having ultra water repellency the surfaces have reduced ice adhesion and can delay water freezing. However, the structure or texture (roughness) of the superhydrophobic surface is subject to degradation during the thermocycling or wetting process. This degradation can impair the superhydrophobicity and the icephobicity of those coatings. In this review, a brief overview of the process of droplet freezing on superhydrophobic coatings is presented with respect to their potential in anti-icing applications. To support this discussion, new data is presented about the condensation of water onto physically decorated substrates, and the associated freezing process which impacts on the freezing of macroscopic droplets on the surface. PMID:24200089

Oberli, Linda; Caruso, Dean; Hall, Colin; Fabretto, Manrico; Murphy, Peter J; Evans, Drew

2014-08-01

272

Effect of freezing and dehydration on ion and cryoprotectant distribution and hemolymph volume in the goldenrod gall fly, Eurosta solidaginis  

Microsoft Academic Search

Extracellular freezing and dehydration concentrate hemolymph solutes, which can lead to cellular injury due to excessive water loss. Freeze tolerant larvae of the goldenrod gall fly, Eurosta solidaginis, may experience extreme cold and desiccation in winter. To determine whether larvae employ protective mechanisms against excessive cellular water loss we examined the effect of extracellular freezing and dehydration on hemolymph volume,

Jason B. Williams; Richard E. Lee

2011-01-01

273

POINT-OF-USE/POINT-OF-ENTRY SYSTEMS FOR REMOVING VOCS (VOLATILE ORGANIC COMPOUNDS) FROM DRINKING WATER  

EPA Science Inventory

Where available, centralized treatment is the recommended method for producing potable water. Many homes, however, can not connect to a centralized water treatment system leaving them with no other alternative but to treat their own water. POU/POE systems are effective for removi...

274

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

275

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 snakes must drink fresh water to maintain water balance? 3. Where can a marine snake find freshwater snakes, water balance, etc.). Give the full citation for the article (Author, year, article title journal

Mitchell, Randall J.

276

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

277

Food freezing with simultaneous surface dehydration: approximate prediction of weight loss during freezing and storage  

Microsoft Academic Search

Weight loss of unpackaged foods during freezing and later storage is an important quality and economic issue. It is originated on surface ice sublimation due to differences in water activity between food surface and the refrigerating air. Weight loss rate is determined by refrigerating conditions and product characteristics. The modelling of this phenomenon has merited very little attention; at present

Laura A. Campañone; Viviana O. Salvadori; Rodolfo H. Mascheroni

2005-01-01

278

A NEW FREEZING-ULTRAMICROTOME  

Microsoft Academic Search

The difficulties in sectioning frozen biological objects for electron microscopic investigations are overcome by Steere's freezing-etching method. In order to test this method and to open up a wide field of application, the new freezing-ultramicrotome has been designed. The apparatus consists of the combination of an ultramicrotome with freezing-drying and shadow-casting installations in the same vacuum container. The preliminary results

H. Moor; K. MtSHLETHALER; H. WALDNER; A. FREY-WYSSLING

1961-01-01

279

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

280

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

281

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

282

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

283

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...

284

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

285

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

286

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

287

The temperature of Europa's subsurface water ocean  

Microsoft Academic Search

A 100 km deep liquid water ocean probably underlies the icy exterior of Jupiter's satellite Europa. The long-term persistence of a liquid ocean beneath an ice shell presents a thermal conundrum: Is the temperature of the ocean equal to the freezing point of water at the bottom of the ice shell, or is it equal to the somewhat warmer temperature at

H. J. Melosh; A. G. Ekholm; A. P. Showman; R. D. Lorenz

2004-01-01

288

Effects of freezing on plant mesophyll cells.  

PubMed

Freezing and thawing of leaves of herbaceous plants leads to damage when the freezing temperature falls below a certain tolerance limit, which depends on the plant species and state of acclimation. Such damage is expressed as an irreversible inhibition of photosynthesis observed after thawing. In frost-damaged leaves the capacity of photosynthetic reactions of the thylakoid membranes is impaired. Particularly, the water-oxidation system, photosystems II and I are inhibited. However, it appears that CO2 assimilation is more readily affected by freezing stress than the activity of the thylakoids. The inhibition of CO2 fixation seen in initial stages of damage seems to be independent of thylakoid inactivation. This can be shown by chlorophyll fluorescence analysis made simultaneously with measurement of CO2 assimilation. Fluorescence emission by leaves is strongly influenced by carbon assimilation activity, namely via the redox state of the photosystem II electron acceptor QA (QA-dependent quenching) and via energization of the thylakoid membranes depending on the transthylakoid proton gradient (energy-dependent quenching). Resolution of these components of fluorescence changes provides insight into alterations of the CO2 fixing capacity of the chloroplasts and properties of the thylakoids. The effects of freezing and thawing were studied in detail with isolated mesophyll protoplasts prepared from both non-hardened and cold-acclimated plants of Valerianella locusta L. Freezing damage was characterized by various parameters such as plasma membrane integrity, photosynthetic CO2 assimilation, chlorophyll fluorescence emission and activities of thylakoids isolated from the protoplasts. All tests indicated a substantially increased frost tolerance of protoplasts obtained from cold-acclimated as compared to non-hardened leaves. CO2 assimilation and related fluorescence changes were the most freezing-sensitive parameters in both types of protoplasts. Inactivation of CO2 assimilation was correlated neither to the disintegration of the plasma membrane nor to inactivation of the thylakoids. Experimental data indicate that freeze-thaw treatment affected the light-regulated enzymes of the carbon reduction cycle, such as fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase and ribulose-1,5-bisphosphate carboxylase. Inhibition of light-activation of these enzymes may be based on altered properties of the chloroplast envelope. PMID:3077862

Krause, G H; Grafflage, S; Rumich-Bayer, S; Somersalo, S

1988-01-01

289

Control of glycerol production by rainbow smelt (Osmerus mordax) to provide freeze resistance and allow foraging at low winter temperatures.  

PubMed

The rainbow smelt (Osmerus mordax) is a small anadromous fish that actively feeds under the ice at temperatures as low as the freeze point of seawater. Freezing is avoided through the production of both non-colligative antifreeze protein (AFP) and glycerol that acts in a colligative manner. Glycerol is constantly lost across the gills and skin, thus glycerol production must continue on a sustained basis at low winter temperatures. AFP begins to accumulate in early fall while water temperatures are still high. Glycerol production is triggered when water temperatures decrease to about 5 degrees C. Glycerol levels rapidly increase with carbon flow from dihydroxyacetone phosphate (DHAP) to glycerol 3-phosphate (G3P) to glycerol. Glucose/glycogen serves as the initial carbon source for glycerol accumulation with amino acids contributing thereafter. The period of glycerol accumulation is associated with increases in GPDH mRNA and PEPCK mRNA followed by elevations in protein synthesis and enzyme activities. Plasma glycerol levels may reach in excess of 500 mM in winter. The high freeze resistance allows rainbow smelt to invade water of low temperature and forage for food. The lower the temperature, the higher the glycerol must be, and the higher the glycerol the greater the loss to the environment through diffusion. During the winter, rainbow smelt feed upon protein rich invertebrates with glycerol production being fueled in part by dietary amino acids via the gluconeogenic pathway. At winter temperatures, glycerol is quantitatively more important than AFP in providing freeze resistance of blood; however, the importance of AFPs to other tissues is yet to be assessed. Glycerol levels rapidly plummet in the spring when water temperature is still close to 0 degrees C. During this period, freeze resistance must be provided by AFP alone. Overall, the phenomenon of glycerol production by rainbow smelt reveals an elegant connection of biochemistry to ecology that allows this species to exploit an otherwise unavailable food resource. PMID:15544960

Driedzic, William R; Ewart, K Vanya

2004-11-01

290

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

2014-08-01

291

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

292

Cloud-point extraction, preconcentration, and spectrophotometric determination of palladium in water samples  

Microsoft Academic Search

The possibility of using Thio-Michler's Ketone (TMK), 4,4?-bis(dimethylamino) thiobenzophenone, for palladium(II) concentrated by micellar extraction at the cloud-point temperature, and later spectrophotometric determination, was investigated. Under the optimum conditions, preconcentration of 50?mL of water samples in the presence of 0.1% (w\\/v) octylphenoxy polyethoxy ethanol (Triton X-114), 2?×?10?mol?L?TMK and 1?×?10?mol?L buffer solution (pH?=?3.0) gave the limit of detection of 0.47?ng?mL, and

Farzaneh Shemirani; Reyhaneh Rahnama Kozani; Mohammad Reza Jamali; Yaghoub Assadi; Mohammad-Reza Milani Hosseini

2006-01-01

293

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Freezing operations. 590...Animal Products FOOD SAFETY AND INSPECTION...Requirements § 590.536 Freezing operations. (a...examination after freezing to determine their fitness for human food. Any such...

2013-01-01

294

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Freezing facilities. 590.534 ...Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE...Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off...

2013-01-01

295

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Freezing facilities. 590.534 ...Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE...Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off...

2010-01-01

296

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Freezing facilities. 590.534 ...Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE...Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off...

2012-01-01

297

9 CFR 590.534 - Freezing facilities.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Freezing facilities. 590.534 ...Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE...Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off...

2011-01-01

298

9 CFR 590.534 - Freezing facilities.  

...2014-01-01 2014-01-01 false Freezing facilities. 590.534 ...Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE...Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off...

2014-01-01

299

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Freezing operations. 590...Animal Products FOOD SAFETY AND INSPECTION...Requirements § 590.536 Freezing operations. (a...examination after freezing to determine their fitness for human food. Any such...

2012-01-01

300

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Freezing operations. 590...Animal Products FOOD SAFETY AND INSPECTION...Requirements § 590.536 Freezing operations. (a...examination after freezing to determine their fitness for human food. Any such...

2010-01-01

301

9 CFR 590.536 - Freezing operations.  

...2014-01-01 false Freezing operations. 590...Animal Products FOOD SAFETY AND INSPECTION...Requirements § 590.536 Freezing operations. (a...examination after freezing to determine their fitness for human food. Any such...

2014-01-01

302

9 CFR 590.536 - Freezing operations.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Freezing operations. 590...Animal Products FOOD SAFETY AND INSPECTION...Requirements § 590.536 Freezing operations. (a...examination after freezing to determine their fitness for human food. Any such...

2011-01-01

303

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

304

33 CFR 149.575 - How must objects protruding from the water, other than platforms and single point moorings, be...  

33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false How must objects protruding from the water, other than platforms and single point...Section 149.575 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF...

2014-07-01

305

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

306

Freezing in Sealed Capillaries for Preparation of Frozen Hydrated Sections  

PubMed Central

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

Yakovlev, Sergey; Downing, Kenneth H.

2014-01-01

307

The North Cape oil spill: hydrocarbons in Rhode Island coastal waters and Point Judith Pond.  

PubMed

On 19 January 1996, the North Cape oil barge ran aground near Moonstone Beach, RI, and spilled over 2700 metric tons of No. 2 fuel oil during a severe winter storm. High winds and rough seas drove the oil into the water column, and the oil spread throughout Block Island Sound and into several coastal salt ponds. Over 50 water samples were collected from Point Judith Pond (PJP) and the southern coast of Rhode Island for four months after the spill and analyzed for polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs). These analyses revealed that at least 60 km2 of coastal waters were impacted from the spill. Maximum concentrations of sigmaPAHs and TPHs were 115 and 3940 microg l(-1), respectively. The percentage of sigmaPAHs relative to the TPHs for all samples varied from 0.2 to 43%, showing that there was no clear relationship between sigmaPAHs and TPHs for the whole dataset and likely resulting from spatial and temporal partitioning over the course of the spill. However, within the dataset, there were stronger correlations for distinct samples collected at similar locations and times. In PJP, water column concentrations of individual PAHs decreased at rates of 0.08-0.24 day(-1) and lower-molecular weight PAHs were removed faster than higher-molecular weight PAHs. PMID:11763148

Reddy, C M; Quinn, J G

2001-12-01

308

Point-of-use reduction of volatile halogenated organics in drinking water. Final report, September 1982-March 1985  

SciTech Connect

Contamination of drinking water by organic chemicals has become a national problem of increasing concern. Small communities faced with the problem of removing these contaminants have limited resources and often cannot afford traditional treatment approaches. One approach which has the potential to be cost effective is treatment at the home, or point-of-use treatment. This report discusses the results of a study of point-of-use treatment of contaminated ground water in two small communities. Costs for purchase, installation, monitoring, and maintenance are documented and discussed. The effect of the point-of-use treatment on the drinking-water quality is presented.

Bellen, G.; Gottler, R.; Anderson, M.

1985-09-01

309

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; Th?gersen, Lea; Schi?tt, Birgit; Tajkhorshid, Emad

2012-01-01

310

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

NASA Astrophysics Data System (ADS)

Fate of dissolved arsenic in ground water at the point of discharge into surface water raises a concern about the public health and the environment due to a potential of arsenic accumulation in the bottom sediments. Dissolved arsenic may become sorbed on amorphous precipitates of ferric hydroxides formed by a changing redox potential during the discharge and then locally deposited. Many landfill plumes and natural reducing ground waters in Central Massachusetts have dissolved arsenic well above the EPA 10 ? g/L MCL level that could cause a local arsenic accumulation. The area of this study stretches along several man-made ponds in North Central Massachusetts located down gradient from (1) a landfill plume in which dissolved arsenic ranges between 50 and 700 ? g/L occasionally up to 5,000 ? g/L; (2) reduced natural ground water where dissolved arsenic can be as high as 200 ? g/L; and (3) oxygenated natural ground water with dissolved arsenic levels below 10 ? g/L. Bottom sediments were collected at 34 separate sites and additional samples were obtained from two to three foot cores at a subset of 9 sites. All samples were analyzed for extractable As, Fe, Ni, and other metals. Samples of bottom sediments near a discharge of the landfill plume form a layer highly enriched in Fe and As. Iron approaches the composition of 100% ferric hydroxides (390,000 and 420,000 mg/kg of Fe respectively). Corresponding arsenic values are 6,800 and 3,900 mg/kg which are nearly 100x the typical background values of arsenic in soils in this area. Arsenic concentrations in other sediments of the landfill plume area have a range from 220 to 2,000 mg/kg. Depth gradients from core sections indicate a decreasing As and Fe trend, yet significantly elevated arsenic levels are still detected at 2 ft depth (30 to 1,200 mg/kg of As). Sediments from the area where a reducing natural water mixes with the surface water have arsenic values that are 3 to 5 times the background soils (As range in the sediments: 66 to 140 mg/kg); no arsenic was detected at 2 ft depth (typical detection limit between 10 and 20 mg/kg). Sediments from the discharge area of oxygenated ground water have arsenic values indistinguishable from the background soils.

Brandon, W. C.; Hon, R.

2004-12-01

311

Freezing survival and cryoprotective dehydration as cold tolerance mechanisms in the Antarctic nematode Panagrolaimus davidi  

Microsoft Academic Search

The relative importance of freezing tolerance and cryoprotective dehydration in the Antarctic nematode Panagrolaimus davidi has been investigated. If nucleation of the medium is initiated at a high subzero temperature (-1°C), the nematodes do not freeze but dehydrate. This effect occurs in deionised water, indicating that the loss of water is driven by the difference in vapour pressure of ice

David A. Wharton; Gordon Goodall; Craig J. Marshall

2003-01-01

312

Freezing of barley studied by infrared video thermography.  

PubMed

Freezing of barley (Hordeum vulgare), Hordeum murinum, and Holcus lanatus was studied using infrared video thermography. In the field, ice could enter H. lanatus leaves through hydathodes. In laboratory tests with barley, initially 0.4% of the leaf water froze, spreading in alternate strips of high and low freezing intensity longitudinally at 1 to 4 cm s(-1), and simultaneously spreading laterally at 0.3 cm s(-1). Similar results were obtained in the field with H. lanatus. A distinct second, more intense, freezing event spread slowly from the margins of the leaves toward the midrib. Organs of uprooted barley tested in the laboratory froze in this order: nucleated leaf, roots, older leaves, younger leaves, and secondary tillers. When ice spread from one leaf to the rest of the plant the crown delayed spread to the roots and other leaves. There was a longer delay above than below -2 degrees C, helping to protect the crown from freezing during mild frosts. Initial spread of freezing was not damaging. However, the initial spread is a prerequisite for the second freezing event, which can cause damage. The route of the initial spread of ice may be extracellular, drawing water from more gel-like parts of the cell wall. PMID:11154332

Pearce, R S; Fuller, M P

2001-01-01

313

Freezing of Barley Studied by Infrared Video Thermography1  

PubMed Central

Freezing of barley (Hordeum vulgare), Hordeum murinum, and Holcus lanatus was studied using infrared video thermography. In the field, ice could enter H. lanatus leaves through hydathodes. In laboratory tests with barley, initially 0.4% of the leaf water froze, spreading in alternate strips of high and low freezing intensity longitudinally at 1 to 4 cm s?1, and simultaneously spreading laterally at 0.3 cm s?1. Similar results were obtained in the field with H. lanatus. A distinct second, more intense, freezing event spread slowly from the margins of the leaves toward the midrib. Organs of uprooted barley tested in the laboratory froze in this order: nucleated leaf, roots, older leaves, younger leaves, and secondary tillers. When ice spread from one leaf to the rest of the plant the crown delayed spread to the roots and other leaves. There was a longer delay above than below ?2°C, helping to protect the crown from freezing during mild frosts. Initial spread of freezing was not damaging. However, the initial spread is a prerequisite for the second freezing event, which can cause damage. The route of the initial spread of ice may be extracellular, drawing water from more gel-like parts of the cell wall. PMID:11154332

Pearce, Roger S.; Fuller, Michael P.

2001-01-01

314

Incorporation of copper nanoparticles into paper for point-of-use water purification.  

PubMed

As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 min and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1 ppm). PMID:25014431

Dankovich, Theresa A; Smith, James A

2014-10-15

315

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

316

Accuracy of tropospheric and stratospheric water vapor measurements by the cryogenic frost point hygrometer: Instrumental details and observations  

Microsoft Academic Search

The cryogenic frost point hygrometer (CFH), currently built at the University of Colorado, is a new balloon borne hygrometer, which is capable of continuously measuring water vapor between the surface and the middle stratosphere. The design is loosely based on the old NOAA\\/CMDL frost point hygrometer, with improved accuracy and a number of significant new features that overcome some limitations

H. Vömel; D. E. David; K. Smith

2007-01-01

317

Cloud point extraction, preconcentration and simultaneous spectrophotometric determination of nickel and cobalt in water samples  

NASA Astrophysics Data System (ADS)

Cloud point extraction has been used for the preconcentration and simultaneous spectrophotometric determination of nickel and cobalt after the formation of a complex with 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA), and latter analysis by spectrophotometer using Triton X-114 as surfactant. The parameters affecting the separation phase and detection process were optimized. Under the optimum experimental conditions (i.e. pH=5, 0.07 mM ACDA, Triton X-114 = 0.25% (w/v)), calibration graphs were linear in the range of 20-500 and 20-200 ?g l -1 with detection limits of 10 and 7.5 ?g l -1 for Ni and Co, respectively. The method was applied to the determination of Ni and Co in natural and waste water samples with satisfactory results.

Safavi, A.; Abdollahi, H.; Hormozi Nezhad, M. R.; Kamali, R.

2004-10-01

318

Cloud point extraction, preconcentration and simultaneous spectrophotometric determination of nickel and cobalt in water samples.  

PubMed

Cloud point extraction has been used for the preconcentration and simultaneous spectrophotometric determination of nickel and cobalt after the formation of a complex with 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA), and latter analysis by spectrophotometer using Triton X-114 as surfactant. The parameters affecting the separation phase and detection process were optimized. Under the optimum experimental conditions (i.e. pH=5, 0.07 mM ACDA, Triton X-114=0.25% (w/v)), calibration graphs were linear in the range of 20-500 and 20-200 microg l(-1) with detection limits of 10 and 7.5 microg l(-1) for Ni and Co, respectively. The method was applied to the determination of Ni and Co in natural and waste water samples with satisfactory results. PMID:15350927

Safavi, A; Abdollahi, H; Hormozi Nezhad, M R; Kamali, R

2004-10-01

319

Temperature dependence of water activity in aqueous solutions of sucrose  

Microsoft Academic Search

A comprehensive experimental data analysis was performed to evaluate the effect of temperature on the water activity coefficient and selected excess thermodynamic functions for aqueous solutions of sucrose. A four-suffix Margules equation with temperature-dependent parameters was used to fit thermodynamic data such as the vapor pressure, boiling point, osmotic coefficient, freezing point, sucrose solubility, heat of dilution and specific heat

Maciej Starzak; Mohamed Mathlouthi

2006-01-01

320

[Influence of below-freezing temperatures on the rate of post-mortem metabolism and the water-holding capacity in prerigor frozen beef muscles (author's transl)].  

PubMed

Prerigor beef is very suitable for the production of "bruehwurst" (frankfurter and bologna type sausages) because of its high waterholding capacity (WHC). This high WHC can be preserved for several months by rapid freezing of prerigor beef either unsalted or salted. In order to elucidate the optimum conditions of frozen storage for the preservation of high WHC, intact beef muscle, ground beef and ground, salted (2% NaC1) beef (neck muscles) were frozen at - 18 degrees or --40 degrees C in a thin layer (0.5-1 cm) 30--60 min after slaugther and stored at various temperatures between --5 degrees and --40 degrees C. The changes of biochemical parameters (content of glycogen and lactate, R-value [it corresponds to ATP concentration] and pH) in the tissue and the WHC of raw and heated muscle homogenates, prepared from the frozen material and containing 2% NaC1, were measured and related to time and temperature of frozen storage. At storage temperature of --18 degrees and --40 degrees C no appreciable biochemical changes occur in intact and ground, unsalted tissue over a period of 10 months. Above 18 degrees C, however, rising temperature causes an increased rate of ATP turnover and glycolysis. In ground muscle higher rates of postmortem metabolism are generally found than in the intact tissue. In prerigor salted and frozen beef a faster drug of ATP concentration (increase of R-value) occurs whereas the breakdown of glycogen to lactate is inhibited. The WHC of raw and heated muscle homogenates depends on time and temperature of frozen storage. As soon as the ATP concentration in unsalted beef falls to a level, at which the onset of rigor mortis occurs, the WHC of homogenates decreases markedly. With beef, ground and salted in the prerigor state and than frozen muscle homogenates are obtained which show always a high WHC even after complete breakdown at ATP during frozen storage. These results have practical consequences with regard to processing of hot-deboned beef. PMID:7424171

Fischer, C; Honikel, K O; Hamm, R

1980-09-01

321

Freezing times of regularly shaped food items  

Microsoft Academic Search

The freezing of food is one of the most significant applications of refrigeration. In order for freezing operations to be cost-effective, it is necessary to optimally design the refrigeration equipment. This requires estimation of the freezing times of foods. Numerous semianalytical\\/empirical methods for predicting food freezing times have been proposed. The designer of food refrigeration facilities is thus faced with

Bryan R. Becker; Brian A. Fricke

1999-01-01

322

Assimilating point snow water equivalent data into a distributed snow cover model  

NASA Astrophysics Data System (ADS)

In Switzerland, snow melt dominates the runoff in many watersheds and the total snow storage contributing to discharge can vary largely from year to year. Accurately quantifying snow storage and subsequent runoff is important for regulating lake levels throughout the country. Additionally, melting snow can contribute to floods imposing large damages on infrastructure. To better quantify the snow storage, we examine whether the performance of a distributed snow model improves when applying different methods for assimilating point snow water equivalent (SWE) data. We update the model results by using either the ensemble Kalman filter or a combination of the ensemble Kalman filter and statistical interpolation. The filter performance was assessed by comparing the simulation results against observed SWE and snow covered fraction. We show that a method which assimilates daily changes in SWE performs better than an approach for updating the model using the SWE data directly. Both assimilation methods showed higher model performance than a control simulation not utilizing data assimilation. Both filter simulations also showed better agreements with the SWE observations than an interpolation method optimized for snow data. The results show that the three-dimensional data assimilation methods were useful for transferring the information in the point snow observations across the domain simulated by the distributed snow model.

Magnusson, Jan; Gustafsson, David; Hüsler, Fabia; Jonas, Tobias

2014-05-01

323

Size control in production and freeze-drying of poly-?-caprolactone nanoparticles.  

PubMed

This work is focused on the control of poly-?-caprolactone nanoparticle characteristics, notably size and size distribution, in both the production and preservation (by using freeze-drying) stages. Nanoparticles were obtained by employing the solvent displacement method in a confined impinging jets mixer. The effect of several operating conditions, namely, initial polymer concentration and solvent-to-antisolvent flow rate ratio, and the influence of postprocessing conditions, such as final dilution and solvent evaporation, on nanoparticle characteristics was investigated. Further addition of antisolvent (water) after preparation was demonstrated to be effective in obtaining stable nanoparticles, that is, avoiding aggregation that would result in larger particles. On the contrary, solvent (acetone) evaporation was shown to have a small effect on the final nanoparticle characteristics. Eventually, freeze-drying of the solutions containing nanoparticles, after solvent evaporation, was also investigated. To ensure maximum nanoparticles stability, lyoprotectants (e.g., sucrose and mannitol) and steric stabilizers (e.g., Cremophor EL and Poloxamer 388) had to be added to the suspensions. The efficacy of the selected lyoprotectants, in the presence (or absence) of steric stabilizers, and in various concentrations, to avoid particle aggregation during the freeze-drying process was investigated, thus pointing to the optimal formulation. PMID:24737658

Zelenková, Tereza; Fissore, Davide; Marchisio, Daniele L; Barresi, Antonello A

2014-06-01

324

The classification and assessment of freeze-thaw erosion in Tibet  

Microsoft Academic Search

Freeze-thaw erosion is the third largest soil erosion type after water erosion and wind erosion. Restricted by many factors,\\u000a few researches on freeze-thaw erosion have so far been done at home and abroad, especially those on the assessment method\\u000a of freeze-thaw erosion. Based on the comprehensive analysis of impact factors of free-thaw erosion, this paper chooses six\\u000a indexes, including the

Jianguo Zhang; Shuzhen Liu; Siquan Yang

2007-01-01

325

Experimental system for one-dimensional freezing of undisturbed soil profiles  

Microsoft Academic Search

An inexpensive and easy-to-handle setup for freeze-thaw experiments was developed. The system mimics field conditions, with a relatively deep monolith of undisturbed soil and a soil-air interface as an upper boundary condition. The setup includes a freezing device for vertical freezing of a soil monolith and transducers at several depths in the soil monolith for continuous measurement of unfrozen water

Holger Johnsson; Bo Thunholm; Lars-Christer Lundin

1995-01-01

326

Source to point of use drinking water changes and knowledge, attitude and practices in Katsina State, Northern Nigeria  

Microsoft Academic Search

In many Sub-Saharan countries such as Nigeria, inadequate access to safe drinking water is a serious problem with 37% in the region and 58% of rural Nigeria using unimproved sources. The global challenge to measuring household water quality as a determinant of safety is further compounded in Nigeria by the possibility of deterioration from source to point of use. This

B. Onabolu; O. D. Jimoh; S. B. Igboro; M. K. C. Sridhar; G. Onyilo; A. Gege; R. Ilya

2011-01-01

327

Electrochemical Surface Potential Due to Classical Point Charge Models Drives Anion Adsorption to the Air-Water Interface  

E-print Network

electrostatic surface potential should favor the desorption of anions at the air-water interface. The resultsElectrochemical Surface Potential Due to Classical Point Charge Models Drives Anion Adsorption to the Air-Water Interface Marcel D. Baer, Abraham C. Stern, Yan Levin,*,§ Douglas J. Tobias

Levin, Yan

328

Hydrogen-bond dynamics for the extended simple point-charge model of water Francis W. Starr,1,  

E-print Network

Hydrogen-bond dynamics for the extended simple point-charge model of water Francis W. Starr,1 1999; revised manuscript received 22 February 2000 We study hydrogen-bond dynamics in liquid water and geometric definitions of a hydrogen bond, and employ two analysis methods: i a history-dependent correlation

Stanley, H. Eugene

329

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

Microsoft Academic Search

Here we present a new technique to detect the extent of surface water cover in boreal and arctic regions using the QuikSCAT microwave backscatter signal from 2000 to 2008, and compare these data to satellite and flask based measurements of atmospheric methane concentrations. The QuikSCAT scatterometer provides a high resolution (2.5 km, daily) long term record of fractional water cover,

N. Smith-Downey; R. Fu

2009-01-01

330

Risk-based prioritization of ground water threatening point sources at catchment and regional scales.  

PubMed

Contaminated sites threaten ground water resources all over the world. The available resources for investigation and remediation are limited compared to the scope of the problem, so prioritization is crucial to ensure that resources are allocated to the sites posing the greatest risk. A flexible framework has been developed to enable a systematic and transparent risk assessment and prioritization of contaminant point sources, considering the local, catchment, or regional scales (Danish EPA, 2011, 2012). The framework has been tested in several catchments in Denmark with different challenges and needs, and two of these are presented. Based on the lessons learned, the Danish EPA has prepared a handbook to guide the user through the steps in a risk-based prioritization (Danish EPA, 2012). It provides guidance on prioritization both in an administratively defined area such as a Danish Region, and within the bounds of a specified ground water catchment. The handbook presents several approaches in order to prevent the prioritization from foundering because of a lack of data or an inappropriate level of complexity. The developed prioritization tools, possible graphical presentation and use of the results are presented using the case studies as examples. The methodology was developed by a broad industry group including the Danish EPA, the Danish Regions, the Danish Nature Agency, the Technical University of Denmark, and consultants - and the framework has been widely accepted by the professional community in Denmark. The concepts are quite general and can be applied in other countries facing similar challenges. PMID:24739894

Overheu, Niels Døssing; Tuxen, Nina; Flyvbjerg, John; Aabling, Jens; Andersen, Jens Asger; Pedersen, Jørn K; Thyregod, Tina; Binning, Philip J; Bjerg, Poul L

2014-07-01

331

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

332

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

333

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

334

Freezing and ice crystals formed in a cylindrical food model: part I. Freezing at atmospheric pressure  

Microsoft Academic Search

Cylindrical gelatin gels were frozen at atmospheric pressure with different operating conditions (air-blast freezing at different air temperatures and brine freezing). A method to calculate a local freezing rate was proposed to take into account the variation of freezing rate as a function of the radius. A linear evolution of the local freezing rate according to the radius was observed

D Chevalier; A Le Bail; M Ghoul

2000-01-01

335

Freeze concentration effects on ice (photo) chemical kinetics investigated by UV-Vis spectroscopy  

NASA Astrophysics Data System (ADS)

We will describe the setup of a fiber coupled UV-Vis spectrometer to investigate the chemistry and photochemistry of aqueous solutions before and after freezing. The photochemical degradation of pyranine at the isosbestic point was investigated. Direct photochemical degradation was minor compared to indirect degradation through hydroxyl radical (OH) attack at room temperature. At -10 C indirect OH degradation was increased relative to room temperature studies, and has been attributed to the freeze concentration effect. The reaction of bromate with bromide in the presence of acid to form molecular bromine was investigated. Upon freezing the formation rate of bromine significantly increases, which we attribute to the freeze concentration effect.

Newberg, J. T.; Arble, C.; Zhang, J.

2013-12-01

336

The original Plank equation and its use in the development of food freezing rate predictions  

Microsoft Academic Search

A large number of methods to predict freezing and thawing times for foodstuffs have been proposed. Normally the original Plank equation is used as the starting point, but since this equation does not include the times below and above the freezing itself, several attempts have been made to improve it by adding new terms and parameters, to make it suitable

Miguel López-Leiva; Bengt Hallström

2003-01-01

337

Freezing of 4 He and its liquid-solid interface from density functional theory  

E-print Network

of the crystal growth can be studied over a wide temperature range, in principle down to absolute zero. Helium phenomenon of crystallization waves, i.e., melting-freezing waves which can easily propagate on the liquid freezing in classical systems for a review see, e.g., Refs. 12­14 . The common point of vi

Caupin, Frédéric

338

Freeze avoidance: a dehydrating moss gathers no ice.  

PubMed

Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water-filled hydroid cells cavitated and were embolized at -4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ? 20% of their original volume at a nadir temperature of -20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from -20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ?-12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to -20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes. PMID:20525002

Lenné, Thomas; Bryant, Gary; Hocart, Charles H; Huang, Cheng X; Ball, Marilyn C

2010-10-01

339

Validation of Aura Microwave Limb Sounder stratospheric water vapor measurements by the NOAA frost point hygrometer  

NASA Astrophysics Data System (ADS)

between stratospheric water vapor measurements by NOAA frost point hygrometers (FPHs) and the Aura Microwave Limb Sounder (MLS) are evaluated for the period August 2004 through December 2012 at Boulder, Colorado, Hilo, Hawaii, and Lauder, New Zealand. Two groups of MLS profiles coincident with the FPH soundings at each site are identified using unique sets of spatiotemporal criteria. Before evaluating the differences between coincident FPH and MLS profiles, each FPH profile is convolved with the MLS averaging kernels for eight pressure levels from 100 to 26 hPa (~16 to 25 km) to reduce its vertical resolution to that of the MLS water vapor retrievals. The mean FPH - MLS differences at every pressure level (100 to 26 hPa) are well within the combined measurement uncertainties of the two instruments. However, the mean differences at 100 and 83 hPa are statistically significant and negative, ranging from -0.46 ± 0.22 ppmv (-10.3 ± 4.8%) to -0.10 ± 0.05 ppmv (-2.2 ± 1.2%). Mean differences at the six pressure levels from 68 to 26 hPa are on average 0.8% (0.04 ppmv), and only a few are statistically significant. The FPH - MLS differences at each site are examined for temporal trends using weighted linear regression analyses. The vast majority of trends determined here are not statistically significant, and most are smaller than the minimum trends detectable in this analysis. Except at 100 and 83 hPa, the average agreement between MLS retrievals and FPH measurements of stratospheric water vapor is better than 1%.

Hurst, Dale F.; Lambert, Alyn; Read, William G.; Davis, Sean M.; Rosenlof, Karen H.; Hall, Emrys G.; Jordan, Allen F.; Oltmans, Samuel J.

2014-02-01

340

33 CFR 154.2112 - Vapors with potential to polymerize or freeze-Special requirements.  

... Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Vapors with potential to polymerize or freeze-Special... Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 154.2112 Vapors with potential to polymerize or...

2014-07-01

341

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

342

Using the phase diagram of liquid water to search for life  

Microsoft Academic Search

The correlation between liquid water and life may be our most reliable tool in the search for extraterrestrial life. To help develop this tool, we explore the complex relationship between liquid water, partial pressure, and solute freezing point depression on Earth and Mars and discuss the conditions under which liquid water is metastable on Mars. We establish the physical conditions

E. G. Jones; C. H. Lineweaver

2012-01-01

343

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

344

Freeze-fracture cytochemistry: partition of glycophorin in freeze- fractured human erythrocyte membranes  

PubMed Central

Thin-section and critical-point-dried fracture-labeled preparations are used to determine the distribution and partition of glycophorin- associated wheat germ agglutinin (WGA) binding sites over protoplasmic and exoplasmic faces of freeze-fractured human erythrocyte membranes. Most wheat germ agglutinin binding sites are found over exoplasmic faces. Label is sparse over the protoplasmic faces. These results contrast with previous observations of the partition of band 3 component where biochemical analysis and fracture-label of concanavalin A (Con A) binding sites show preferential partition of this transmembrane protein with the protoplasmic face. Presence of characteristic proportions of WGA and Con A binding sites over each fracture face is interpreted to indicate the operation of a stochastic process during freeze-fracture. This process appears modulated by the relative expression of each transmembrane protein at either surface as well as by their association to components of the erythrocyte membrane skeleton. PMID:7096449

1982-01-01

345

The Ammonia Freeze Explosion (AFEX) process  

SciTech Connect

The Ammonia Freeze Explosion (AFEX) process treats lignocellulose with high-pressure liquid ammonia, and then explosively releases the pressure. The combined chemical effect (cellulose decrystallization) and physical effect (increased accessible surface area) dramatically increase lignocellulose susceptibility to enzymatic attack. There are many adjustable parameters in the AFEX process: ammonia loading, water loading, temperature, time, blowdown pressure, and number of treatments. The effect of these parameters on enzymatic susceptibility was explored for three materials: Coastal bermudagrass, bagasse, and newspaper. Nearly quantitative sugar yields were demonstrated for Coastal bermudagrass and bagasse, using a very low enzyme loading (5 IU/g). Newspaper proved to be much more resistant to enzymatic hydrolysis.

Holtzapple, M.T.; Jae-Hoon Jun; Ganesh Ashok; Patibandla, S.L.; Dale, B.E. [Texas A& M Univ., College Station, TX (United States)

1991-12-31

346

A chemical test of the principle of critical point universality: the solubility of nickel (II) oxide in isobutyric acid + water near the consolute point.  

PubMed

A mixture of isobutyric acid + water has an upper consolute point at 38.8 mass?% isobutyric acid and temperature near 26?°C. Nickel (II) oxide dissolves in this mixture by reacting with the acid to produce water and nickel isobutyrate. The solubility of nickel (II) oxide in isobutyric acid + water has been measured as a function of temperature at compositions, 25, 38.8, and 60 mass?% isobutyric acid. For values of the temperature, T, which were at least 2 K in excess of the liquid-liquid phase transition temperature, the measured values of the solubility, s, lie on a straight line when plotted in van't Hoff form with ln?s versus 1?T. The slope, (?ln?s??(1?T)), of the line is negative indicating that the dissolution reaction is endothermic. When the temperature was within 2 K of the phase transition temperature, however, (?ln?s??(1?T)) diverged toward negative infinity. The principle of critical point universality predicts that when excess solid nickel (II) oxide is in dissolution equilibrium with liquid isobutyric acid + water, (?ln?s??(1?T)) should diverge upon approaching the consolute point along the critical isopleth at 38.8 mass?% isobutyric acid. As determined by the sign of the enthalpy of solution, the sign of this divergence is expected to be negative. Not only do our experiments confirm these predictions, but they also show that identical behavior can be observed at both 25 and 60 mass?% isobustyric acid, compositions which lie substantially to either side of the critical composition. PMID:21513393

Hu, Baichuan; Baird, James K; Richey, Randi D; Reddy, Ramana G

2011-04-21

347

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

PubMed

Communicable diseases are of particular concern in conflict and disaster-affected populations that reside in camp settings. In the acute emergency phase, diarrhoeal diseases have accounted for more than 40% of deaths among camp residents. Clear limitations exist in current water treatment technologies, and few products are capable of treating turbid water. We describe the findings of a 12-week effectiveness study of point-of-use water treatment with a flocculant-disinfectant among 400 households in camps for displaced populations in Monrovia, Liberia. In intervention households, point-of-use water treatment with the flocculant-disinfectant plus improved storage reduced diarrhoea incidence by 90% and prevalence by 83%, when compared with control households with improved water storage alone. Among the intervention group, residual chlorine levels met or exceeded Sphere standards in 85% (95% CI: 83.1-86.8) of observations with a 95% compliance rate. PMID:17002728

Doocy, Shannon; Burnham, Gilbert

2006-10-01

348

Synchrotron X-Ray Visualisation of Ice Formation in Insects during Lethal and Non-Lethal Freezing  

PubMed Central

Although the biochemical correlates of freeze tolerance in insects are becoming well-known, the process of ice formation in vivo is subject to speculation. We used synchrotron x-rays to directly visualise real-time ice formation at 3.3 Hz in intact insects. We observed freezing in diapausing 3rd instar larvae of Chymomyza amoena (Diptera: Drosophilidae), which survive freezing if it occurs above ?14°C, and non-diapausing 3rd instar larvae of C. amoena and Drosophila melanogaster (Diptera: Drosophilidae), neither of which survive freezing. Freezing was readily observed in all larvae, and on one occasion the gut was seen to freeze separately from the haemocoel. There were no apparent qualitative differences in ice formation between freeze tolerant and non-freeze tolerant larvae. The time to complete freezing was positively related to temperature of nucleation (supercooling point, SCP), and SCP declined with decreasing body size, although this relationship was less strong in diapausing C. amoena. Nucleation generally occurred at a contact point with the thermocouple or chamber wall in non-diapausing larvae, but at random in diapausing larvae, suggesting that the latter have some control over ice nucleation. There were no apparent differences between freeze tolerant and non-freeze tolerant larvae in tracheal displacement or distension of the body during freezing, although there was markedly more distension in D. melanogaster than in C. amoena regardless of diapause state. We conclude that although control of ice nucleation appears to be important in freeze tolerant individuals, the physical ice formation process itself does not differ among larvae that can and cannot survive freezing. This suggests that a focus on cellular and biochemical mechanisms is appropriate and may reveal the primary adaptations allowing freeze tolerance in insects. PMID:20011523

Sinclair, Brent J.; Gibbs, Allen G.; Lee, Wah-Keat; Rajamohan, Arun; Roberts, Stephen P.; Socha, John J.

2009-01-01

349

Monitoring Seasonal Landscape Freeze/Thaw Processes with SMAP  

NASA Astrophysics Data System (ADS)

Major science objectives of SMAP support understanding of processes linking terrestrial water, energy and carbon cycles and quantify net carbon flux. The landscape transition between seasonally frozen and non- frozen conditions occurs each year over more than 50 million km2 of the global biosphere, affecting hydrological and ecological processes and associated trace gas dynamics profoundly. The SMAP suite of data products will include maps of landscape freeze/thaw state derived from L-band radar at 1-3 km spatial resolution with a 2-day refresh rate for the high northern latitudes (i.e. latitudes above 50 degrees north). Satellite active and passive microwave remote sensing can be applied to detect large changes in landscape dielectric properties associated with water transitioning between frozen and non-frozen conditions. In the northern high latitudes, seasonal freeze/thaw transitions associated with this process dominate time-series microwave remote sensing signatures. The SMAP freeze/thaw algorithm employs a temporal change detection scheme to delineate freeze/thaw state changes associated with temporal variations in landscape dielectric properties. Development of the algorithm follows from application of legacy data sets provided by satellite radars, both scatterometers and Synthetic Aperture Radars (SARs), and radiometers. This presentation reviews algorithm development and applications, and associated SMAP science objectives addressed through the derived freeze/thaw data products. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, and at the University of Montana under contract to the National Aeronautics and Space Administration.

McDonald, K. C.; Kimball, J. S.

2008-12-01

350

Not Just a Drop in the Bucket: Expanding Access to Point-of-Use Water Treatment Systems  

PubMed Central

Since 1990, the number of people without access to safe water sources has remained constant at approximately 1.1 billion, of whom approximately 2.2 million die of waterborne disease each year. In developing countries, population growth and migrations strain existing water and sanitary infrastructure and complicate planning and construction of new infrastructure. Providing safe water for all is a long-term goal; however, relying only on time- and resource-intensive centralized solutions such as piped, treated water will leave hundreds of millions of people without safe water far into the future. Self-sustaining, decentralized approaches to making drinking water safe, including point-of-use chemical and solar disinfection, safe water storage, and behavioral change, have been widely field-tested. These options target the most affected, enhance health, contribute to development and productivity, and merit far greater priority for rapid implementation. PMID:11574307

Mintz, Eric; Bartram, Jamie; Lochery, Peter; Wegelin, Martin

2001-01-01

351

Real-time retrieval of precipitable water vapor from GPS precise point positioning  

NASA Astrophysics Data System (ADS)

of precipitable water vapor (PWV) using the Global Positioning System (GPS) has been intensively investigated in the past 2 decades. However, it still remains a challenging task at a high temporal resolution and in the real-time mode. In this study the accuracy of real-time zenith total delay (ZTD) and PWV using the GPS precise point positioning (PPP) technique is investigated. GPS observations in a 1 month period from 20 globally distributed stations are selected for testing. The derived real-time ZTDs at most stations agree well with the tropospheric products from the International Global Navigation Satellite Systems Service, and the root-mean-square errors (RMSEs) are <13 mm, which meet the threshold value of 15 mm if ZTDs are input to numerical weather prediction models. The RMSE of the retrieved PWVs in comparison with the radiosonde-derived values are ?3 mm, which is the threshold RMSE of PWVs as inputs to weather nowcasting. The theoretical accuracy of PWVs is also discussed, and 3 mm quality of PWVs is proved achievable in different temperature and humidity conditions. This implies that the real-time GPS PPP technique can be complementary to current atmospheric sounding systems, especially for nowcasting of extreme weather due to its real-time, all-day, and all-weather capabilities and high temporal resolutions.

Yuan, Yubin; Zhang, Kefei; Rohm, Witold; Choy, Suelynn; Norman, Robert; Wang, Chuan-Sheng

2014-08-01

352

Measuring and modeling hemoglobin aggregation below the freezing temperature.  

PubMed

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

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

2013-08-01

353

Designing a Policy Mix and Sequence for Mitigating Agricultural NonPoint Source Pollution in a Water Supply Catchment  

Microsoft Academic Search

Agricultural non-point source pollution, common in water supply catchments worldwide, can have significant environmental and\\u000a human health impacts, and its mitigation poses a challenge for policymakers. We used deliberative multi-criteria evaluation\\u000a (DMCE) to identify a mix and sequence of policy instruments (or policy design) to address agricultural non-point source pollution using a case study of Cryptosporidium contamination in the Myponga

Brett A. Bryan; John M. Kandulu

2011-01-01

354

Source to point of use drinking water changes and knowledge, attitude and practices in Katsina State, Northern Nigeria  

NASA Astrophysics Data System (ADS)

In many Sub-Saharan countries such as Nigeria, inadequate access to safe drinking water is a serious problem with 37% in the region and 58% of rural Nigeria using unimproved sources. The global challenge to measuring household water quality as a determinant of safety is further compounded in Nigeria by the possibility of deterioration from source to point of use. This is associated with the use of decentralised water supply systems in rural areas which are not fully reticulated to the household taps, creating a need for an integrated water quality monitoring system. As an initial step towards establishing the system in the north west and north central zones of Nigeria, The Katsina State Rural Water and Sanitation Agency, responsible for ensuring access to safe water and adequate sanitation to about 6 million people carried out a three pronged study with the support of UNICEF Nigeria. Part 1 was an assessment of the legislative and policy framework, institutional arrangements and capacity for drinking water quality monitoring through desk top reviews and Key Informant Interviews (KII) to ascertain the institutional capacity requirements for developing the water quality monitoring system. Part II was a water quality study in 700 households of 23 communities in four local government areas. The objectives were to assess the safety of drinking water, compare the safety at source and household level and assess the possible contributory role of end users’ Knowledge Attitudes and Practices. These were achieved through water analysis, household water quality tracking, KII and questionnaires. Part III was the production of a visual documentary as an advocacy tool to increase awareness of the policy makers of the linkages between source management, treatment and end user water quality. The results indicate that except for pH, conductivity and manganese, the improved water sources were safe at source. However there was a deterioration in water quality between source and point of use in 18%, 12.5%, 27% and 50% of hand pump fitted boreholes, motorised boreholes, hand dug wells and streams respectively. Although no statistical correlation could be drawn between water management practices and water quality deterioration, the survey of the study households gave an indication of the possible contributory role of their knowledge, attitudes and practices to water contamination after provision. Some of the potential water related sources of contamination were poor source protection and location, use of unimproved water source and poor knowledge and practice of household water treatment methods, poor hand washing practices in terms of percentage that wash hands and use soap. Consequently 34 WASH departments have been created at the local government level towards establishment of a community based monitoring system and piloting has begun in Kaita local government area.

Onabolu, B.; Jimoh, O. D.; Igboro, S. B.; Sridhar, M. K. C.; Onyilo, G.; Gege, A.; Ilya, R.

355

Quality of Drinking-water at Source and Point-of-consumption - Drinking Cup As a High Potential Recontamination Risk: A Field Study in Bolivia  

Microsoft Academic Search

In-house contamination of drinking-water is a persistent problem in developing countries. This study aimed at identifying critical points of contamination and determining the extent of recontamination after water treatment. In total, 81 households were visited, and 347 water samples from their cur- rent sources of water, transport vessels, treated water, and drinking vessels were analyzed. The quality of water was

Simonne Rufener; Daniel Mäusezahl; Hans-Joachim Mosler; Rolf Weingartner

2010-01-01

356

High rates of energy expenditure and water flux in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea  

USGS Publications Warehouse

We measured water flux and energy expenditure in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea by using the doubly labeled water method. Previous laboratory investigations have suggested weak urinary concentrating ability, high rates of water flux, and low basal metabolic rates in this species. However, free-ranging measurements from hygric mammals are rare, and it is not known how these features interact in the environment. Rates of water flux (210 ?? 32 mL d-1) and field metabolic rates (1,488 ?? 486 kJ d-1) were 159% and 265%, respectively, of values predicted by allometric equations for similar-sized herbivores. Mountain beavers can likely meet their water needs through metabolic water production and preformed water in food and thus remain in water balance without access to free water. Arginine-vasopressin levels were strongly correlated with rates of water flux and plasma urea : creatinine ratios, suggesting an important role for this hormone in regulating urinary water loss in mountain beavers. High field metabolic rates may result from cool burrow temperatures that are well below lower critical temperatures measured in previous laboratory studies and suggest that thermoregulation costs may strongly influence field energetics and water flux in semifossorial mammals. ?? 2007 by The University of Chicago. All rights reserved.

Crocker, D. E.; Kofahl, N.; Fellers, G. D.; Gates, N. B.; Houser, D. S.

2007-01-01

357

Impact of Point and Nonpoint Source Pollution on Pore Waters of Two Chesapeake Bay Tributaries  

Microsoft Academic Search

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

Makesh Karuppiah; Gian Gupta

1996-01-01

358

The effect on recovery of the injection of alternating slugs of gas and water at pressures above the bubble point  

E-print Network

TW EFFECT ON RECOVERY OF THE INJECTION OF ALTERNATING SLUGS OF GAS AND WATER AT PRESSURES ABOVE THE BUBBLE POINT A Thesis by James Wilson Givens Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial... fulfillment of the requirements for the d egree of MASTERS OF SCIENCE August, l96t Major Subject; Petroleum Engineering THE EFFECT ON RECOVERY OF THE INJECTION OF ALTERNATING Sj UGS OF GAS AND WATER AT PRESSURES ABOVE THE BUBBLE POINT A Thesis...

Givens, James Wilson

2012-06-07

359

Ground-water resources in the vicinity of the Crown Point fish hatchery, Essex County, New York  

USGS Publications Warehouse

The Crown Point Fish Hatchery, one of several hatcheries operated by the New York State Conservation Department, is located in Crown Point Center, Essex County, on the eastern edge of the Adirondack Highlands and about 2 miles west of lake Champlain. Figure 1 is a location map of the vicinity of the Hatchery. This report summarizes an investigation by the U.S. Geological Survey, in cooperation with the New York State Conservation Department, Division of Water Resources, to locate and evaluate sources of additional ground-water supply for the Hatchery. In order to expand the facilities at the Hatchery, an additional water supply of about 100 gpm (gallons per minute) to as much as 350 gpm is needed. In addition, the type of fish culture practiced requires a water temperature of about 7 to 13 degrees Celsius (centigrade) for optimum results.

Kantrowitz, I. H.

1968-01-01

360

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

361

Heat transfer with freezing in a scraped surface heat exchanger  

Microsoft Academic Search

An experimental study was carried out on a scraped surface heat exchanger used for freezing of water–ethanol mixture and aqueous sucrose solution. The influence of various parameters on heat transfer intensity was established: product type and composition, flow rate, blade rotation speed, distance between blades and wall. During starting (transient period) the solution is first supercooled, then ice crystals appear

Mohamed Ben Lakhdar; Rosalia Cerecero; Graciela Alvarez; Jacques Guilpart; Denis Flick; André Lallemand

2005-01-01

362

Soil Freeze-Thaw Effects on Bank Erodibility and Stability.  

National Technical Information Service (NTIS)

When air temperature is below ground temperature, a thermal gradient is established in the soil that causes the soil to lose heat to the atmosphere. When the soil has lost sufficient heat for soil water to freeze, the newly formed ice changes soil structu...

L. W. Gatto

1995-01-01

363

A correlation of water solubility in jet fuels with API gravity: aniline point percent aromatics, and temperature.  

E-print Network

A CORRELATION OF WATER SOLUBILITY IN JET FUELS WITH API GRAVITY, ANILINE POINT PERCENT AROMATICS, AND TEMPERATURE A Thesis By ALONZO B YINGTON Submitted to the Graduate College of Texas A&M University in partial fulfillment... mechanisms and adversely affect fuel flow and engine performance. Long range, high altitude flights aggravate the proble~, and the use of micronic filters in fuel lines maximires the danger of plugging from any ice present. The solubility of water...

Byington, Alonzo

2012-06-07

364

Physicochemical and Functional Properties of Freeze-Dried and Oven Dried Corn Gluten Meals  

Microsoft Academic Search

The physicochemical and functional properties of convection oven- and freeze-dried gluten meals of two corn varieties were evaluated. The physicochemical properties (water solubility index, water absorption index, Hunter color parameters, and bulk density) and functional properties (water absorption, oil absorption, least gelation concentration, protein solubility, and emulsification properties) of convection-oven and freeze-dried corn gluten meals were compared with each other

Narpinder Singh; Maninder Kaur; Kawaljit Singh Sandhu

2005-01-01

365

Validation of Aura Microwave Limb Sounder stratospheric water vapor measurements by the NOAA frost point hygrometer  

NASA Astrophysics Data System (ADS)

Differences between stratospheric water vapor measurements by NOAA frost point hygrometers (FPHs) and the Aura Microwave Limb Sounder (MLS) are evaluated for the period August 2004 through December 2012 at three locations: Boulder, Colorado (40.0°N, 105.2°W), Hilo, Hawaii (19.7°N, 155.1°W), and Lauder, New Zealand (45.0°S, 169.7°E). MLS profiles coincident with the FPH soundings at each site are identified using unique sets of temporal and spatial criteria. Each FPH profile is convolved with the MLS averaging kernels to reduce its vertical resolution to that of the MLS water vapor retrievals. No statistically significant biases are found between the convolved FPH profiles and coincident MLS profiles at 8 pressure levels from 100 to 26 hPa (~16 to 25 km) above the three sites. Mean FPH-MLS differences for the 6 MLS retrieval levels from 68 to 26 hPa (~19 to 25 km) range from -0.11×0.18 to 0.12×0.22 ppmv (-2.5×3.9 to 2.5×4.6%). For 68-26 hPa, averages of the mean differences range from -0.07×0.09 to 0.05×0.09 ppmv (-1.6×1.9 to 1.0×1.9%). Below 68 hPa the mean differences become negative and larger, ranging from -0.08×0.31 to -0.29×0.37 ppmv (-2.1×7.8 to -7.3×9.1%) at 83 hPa across Boulder and Hilo, and from -0.22×0.45 to -0.44×0.46 ppmv (-5.5×11.2% to -10.9×11.3%) at 100 hPa across all three sites. At every pressure level from 100 to 26 hPa the mean differences are well within the combined MLS and FPH measurement uncertainties. FPH-MLS differences at each site are analyzed for temporal trends but none are statistically significant.

Hurst, D. F.; Lambert, A.; Read, W. G.; Davis, S. M.; Rosenlof, K. H.; Hall, E. G.; Jordan, A. F.; Oltmans, S. J.

2013-12-01

366

Heat Capacity Anomaly Near the Lower Critical Consolute Point of Triethylamine-Water  

NASA Technical Reports Server (NTRS)

The heat capacity of the binary liquid mixture triethylamine-water has been measured near its lower critical consolute point using a scanning, adiabatic calorimeter. Two data runs are analyzed to provide heat capacity and enthalpy data that are fitted by equations with background terms and a critical term that includes correction to scaling. The critical exponent a was determined to be 0.107 +/- 0.006, consistent with theoretical predictions. When alpha was fixed at 0.11 to determine various amplitudes consistently, our values of A(+) and A(-) agreed with a previous heat capacity measurement, but the value of A(-) was inconsistent with values determined by density or refractive index measurements. While our value for the amplitude ratio A(+)/ A(-) = 0.56 +/- 0.02 was consistent with other recent experimental determinations in binary liquid mixtures, it was slightly larger than either theoretical predictions or recent experimental values in liquid-vapor systems. The correction to scaling amplitude ratio D(+)/D(-) = 0.5 +/- 0.1 was half of that predicted. As a result of several more precise theoretical calculations and experimental determinations, the two-scale-factor universality ratio X, which we found to be 0.019 +/- 0.003, now is consistent among experiments and theories. A new 'universal' amplitude ratio R(sup +/-)(sub Bcr) involving the amplitudes for the specific heat was tested. Our determination of R(sup +/-)(sub Bcr) = -0.5 +/- 0.1 and R(sup -)(sub Bcr) = 1.1 +/- 0.1 is smaller in magnitude than predicted and is the first such determination in a binary fluid mixture.

Flewelling, Anne C.; DeFonseka, Rohan J.; Khaleeli, Nikfar; Partee, J.; Jacobs, D. T.

1996-01-01

367

Selective determination of total vanadium in water samples by cloud point extraction of its ternary complex.  

PubMed

A highly sensitive micelle-mediated extraction methodology for the preconcentration of trace levels of vanadium as a prior step to its determination by flame atomic absorption spectrometry (FAAS) has been developed. Vanadium was complexed with 1-(2-pyridylazo)-2-naphthol (PAN) and hydrogen peroxide in acidic medium (0.2 mol L(-1) phosphoric acid) using Triton X-100 as surfactant and quantitatively extracted into a small volume of the surfactant-rich phase after centrifugation. The color reaction of vanadium ions with hydrogen peroxide and PAN in phosphoric acid medium is highly selective. The chemical variables affecting cloud point extraction (CPE) were evaluated and optimized. The R.S.D. for 5 replicate determinations at the 20 microg L(-1)V level was 3.6%. The calibration graph using the preconcentration system for vanadium was linear with a correlation coefficient of 0.99 at levels near the detection limits up to at least 0.6 microg L(-1). The method has good sensitivity and selectivity and was applied to the determination of trace amounts of vanadium in water samples with satisfactory result. The proposed method is a rare application of CPE-atomic spectrometry to vanadium assay, and is superior to most other similar methods, because its useful pH range is in the moderately acidic range achieved with phosphoric acid. At this pH, many potential interferents are not chelated with PAN, and iron(III) as the major interferent is bound in a stable phosphate complex. PMID:18558120

Filik, Hayati; Yanaz, Zeynep; Apak, Re?at

2008-07-14

368

Time dependence of immersion freezing  

NASA Astrophysics Data System (ADS)

The time dependence of immersion freezing was studied for temperatures between 236 K and 243 K. Droplets with single immersed, size-selected 400 nm and 800 nm kaolinite particles were produced at 300 K, cooled down to supercooled temperatures typical for mixed-phase cloud conditions, and the fraction of frozen droplets with increasing residence time was detected. To simulate the conditions of immersion freezing in mixed-phase clouds we used the Zurich Ice Nucleation Chamber (ZINC) and its vertical extension, the Immersion Mode Cooling chAmber (IMCA). We observed that the frozen fraction of droplets increased with increasing residence time in the chamber. This suggests that there is a time dependence of immersion freezing and supports the importance of a stochastic component in the ice nucleation process. The rate at which droplets freeze was observed to decrease towards higher temperatures and smaller particle sizes. Comparison of the laboratory data with four different ice nucleation models, three based on classical nucleation theory with different representations of the particle surface properties and one singular, suggest that the classical, stochastic approach combined with a distribution of contact angles is able to reproduce the ice nucleation observed in these experiments most accurately. Using the models to calculate the increase in frozen fraction at typical mixed-phase cloud temperatures over an extended period of time, yields an equivalent effect of -1 K temperature shift and an increase in time scale by a factor of ~10.

Welti, A.; Lüönd, F.; Kanji, Z. A.; Stetzer, O.; Lohmann, U.

2012-05-01

369

Ultrasonic monitoring of food freezing  

Microsoft Academic Search

The time of flight of an ultrasonic pulse moving parallel to the direction of heat flux was measured in blocks of food (gelatin, chicken, beef) during freezing. Echoes were recorded from the food surfaces and from the moving ice front within the food. The changing return times of these echoes were used to calculate the percentage of the food frozen

Halldor Sigfusson; Gregory R. Ziegler; John N. Coupland

2004-01-01

370

FREEZING AND THAWING RESISTANCE OF CONCRETE WITH INITIAL CRACK  

NASA Astrophysics Data System (ADS)

Freezing and thawing resistance of concrete with an initial crack was investigated. The specimens were classified into plane concrete, fiber reinforced concrete, and reinforced concrete. In the tests of plane concrete with an initial crack, the crack grows seriously by the frozen expansion pressure of the water infiltrated into the crack, though the concrete material had high resistance to freezing and thawing. In the experimental results of fiber reinforced concrete, the long polypropylene fiber was useful to prevent the spalling of concrete cover, though the crack growth was not prevented. Moreover, in the experimental results of reinforced concrfete, it was shown that the crack growth was effectively prevented by steel reinforcing bar.

Naito, Hideki; Hayashi, Hiroshi; Saiki, Yusuke; Sando, Koichi; Koga, Hideyuki; Suzuki, Motoyuki

371

Performance of residential air-to-air heat exchangers during operation with freezing and periodic defrosts  

Microsoft Academic Search

In a laboratory study of the performance of residential air-to-air heat exchangers during operation with freezing and periodic defrosts, freezing caused the temperature efficiency of a cross-flow heat exchanger to decrease at a rate ranging from 1.5 to 13.2 percentage points per hour. Much smaller rates of decrease in temperature efficiency, 0.6 to 2.0 percentage points per hour, occurred during

W. Fisk; K. Archer; R. Chant; D. Hekmat; F. Offermann; B. Pedersen

1984-01-01

372

A modified homogeneous freezing rate parameterization for aqueous solution droplets  

NASA Astrophysics Data System (ADS)

It is still a matter of debate wether cirrus cloud formation is dominated by heterogeneous ice nucleation, leading to low ice crystal number concentrations, or is also influenced by homogeneous freezing of solution aerosols leading to higher ice crystal number concentrations. Part of the discussion is due to the fact that current models seem to overestimate ice crystal numbers from homogeneous freezing compared to measurements, though the formation rate of cirrus ice crystals by homogeneous freezing of aqueous particles is believed to be well understood and formulated in terms of e.g. the concept of effective freezing temperatures or the water activity dependent ice nucleation rates. Series of recent cirrus cloud simulation experiments at the cloud chamber facility AIDA at the Karlsruhe Institute of Technology at temperatures between -40°C and -80°C together with process modeling studies demonstrated, that the freezing formulations tend to show a low bias in the humidity onset thresholds for homogeneous ice formation at temperatures below about 210 K, and furthermore overestimate the ice formation rate by at least a factor of 2. The experimental results will be summarized and a new empirical fit to the experimental data will be suggested for use in atmospheric models.

Moehler, O.; Benz, S.; Hoehler, K.; Wagner, R.

2012-12-01

373

Comparison of Byproduct Formation in Waters Treated With Chlorine and Iodine: Relevance To Point-Of-Use Treatment  

EPA Science Inventory

Due to their efficacy in deactivating a range of microbial pathogens, particularly amoebic cysts, iodine-based disinfectants have been a popular option for point-of-use (POU) drinking water disinfection by campers, the military, and rural consumers in developing countries. Recent...

374

Source of salts in the Waianae part of the Pearl Harbor aquifer near Barbers Point water tunnel, Oahu, Hawaii  

USGS Publications Warehouse

The salinity of the water supply of Barbers Point Naval Air Station has increased markedly since 1983. The Naval Air Station obtains its water, about 3 million gal/day, from Barbers Point shaft, a water shaft that taps the Waianae part of the Pearl Harbor aquifer underlying the dry, southeastern flank of the Waianae mountains on the island on Oahu, Hawaii. From 1983 to 1985 the chloride concentration of the water, increased from 220 to 250 mg/L and has remained near that level through 1986. The EPA has established 250 mg/L as the maximum recommended chloride concentration in drinking water because above that level many people can taste the salt. The high chloride concentration in shallow groundwater at all wells in the area indicates that most of the salts in the freshwater lens are contributed by rainfall, sea spray, and irrigation return water. At Barbers Point shaft, pumping may draw a small amount of saltwater from the transition zone and increase the chloride concentration in the pumped water by about 20 mg/L. Salinity of the lens decreases progressively inland in response to recharge from relatively fresher water and in response to an increasing lens thickness with increasing distance from the shoreline. The increase, in 1983, in the chloride concentration of water at the shaft was most probably the result of saltier recharge water reaching the water table, and not the result of increased mixing of underlying saltwater with the freshwater. The chloride concentration of the recharge water has probably increased because, in 1980, the drip method of irrigation began to replace the furrow method on sugarcane fields near the shaft. A mixing-cell model was used to estimate the effect of drip irrigation on the chloride concentration of the groundwater in the vicinity of Barbers Point shaft. The model predicted an increase in chloride concentration of about 50 mg/L. The observed increase was about 30 mg/L and the chloride concentration is presently stable at 245 to 250 mg/L; hence, the chloride concentration is not expected to increase significantly more. (Lantz-PTT)

Eyre, P.R.

1987-01-01

375

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

Microsoft Academic Search

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

Jon P. Costanzo; Patrick J. Baker; Richard E. Lee Jr

2006-01-01

376

Freezing: an underutilized food safety technology?  

Microsoft Academic Search

Freezing is an ancient technology for preserving foods. Freezing halts the activities of spoilage microorganisms in and on foods and can preserve some microorganisms for long periods of time. Frozen foods have an excellent overall safety record. The few outbreaks of food-borne illness associated with frozen foods indicate that some, but not all human pathogens are killed by commercial freezing

Douglas L. Archer

2004-01-01

377

Atmospheric Freeze Drying—A Review  

Microsoft Academic Search

This review article focuses on the development of atmospheric freeze drying (AFD): technological aspects, product possibilities, physical properties of products, drying kinetics, modeling, and simulation. The main motivation for developing atmospheric freeze drying as a new drying technology is the desire to reduce the energy consumption compared to vacuum freeze drying while maintaining a high product quality. One technical solution

I. C. Claussen; T. S. Ustad; I. Strømmen; P. M. Walde

2007-01-01

378

Biotechnological applications of plant freezing associated Ghislain Breton1  

E-print Network

, freezing tolerance, frozen food, genetic engineering, organ preservation, osmoprotectants, osmotic stress57 Biotechnological applications of plant freezing associated proteins Ghislain Breton1 , Jean and freezing conditions. The identification of these freezing tolerance associated proteins and the elucidation

Sarhan, Fathey

379

The Electrochemical Surface Potential Due to Classical Point Charge Models Drives Anion Adsorption to the Air-Water Interface  

E-print Network

We demonstrate that the driving forces for ion adsorption to the air-water interface for point charge models results from both cavitation and a term that is of the form of a negative electrochemical surface potential. We carefully characterize the role of the free energy due to the electrochemical surface potential computed from simple empirical models and its role in ionic adsorption within the context of dielectric continuum theory. Our research suggests that the electrochemical surface potential due to point charge models provides anions with a significant driving force to the air-water interface. This is contrary to the results of ab initio simulations that indicate that the average electrostatic surface potential should favor the desorption of anions at the air-water interface. The results have profound implications for the studies of ionic distributions in the vicinity of hydrophobic surfaces and proteins.

Marcel D. Baer; Abraham C. Stern; Yan Levin; Douglas J. Tobias; Christopher J. Mundy

2013-07-05

380

Freezing cleans food processing wastewater  

SciTech Connect

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

Not Available

1998-01-01

381

Water Quality vs. Sanitation Accessibility: What is the most effective intervention point for preventing cholera in Dhaka, Bangladesh?  

NASA Astrophysics Data System (ADS)

Every year, 3 to 5 million individuals contract cholera, an acute diarrheal infection that is caused by the ingestion of food or water containing the Vibrio cholerae bacterium. Because cholera is a waterborne disease, it can be transmitted quickly in environments with inadequate water and sanitation systems where infected waste can easily pollute drinking water. Today, Bangladesh continues to struggle with endemic cholera. Donor organizations address water and sanitation via localized initiatives, including the installation of community water collection sites (i.e. tubewells; water-boiling points; etc.). At this small-scale level, water quality and sanitation accessibility can be improved independently of one another, and when resources are limited, donors must invest in the most effective disease prevention options. This study used laboratory-confirmed cholera incidence data (2000-2009) collected by the International Centre of Diarrheal Disease Research, Bangladesh at their on-site hospital to compare the efficacy of interventions addressing water quality versus sanitation accessibility in Dhaka, Bangladesh. Data regarding use of sanitary latrines and boiling of drinking water were extracted from sequential patient interviews conducted at the Dhaka facility and used as surrogate variables for sanitation accessibility and water quality respectively. Our analysis indicates that boiling water is 10 times more effective at preventing cholera than the use of a sanitary latrine. This finding suggests that regulating water quality is perhaps more critical to cholera prevention than increasing sanitation accessibility in an urban environment like that of Dhaka. At present, WaterAid - one of Bangladesh's most significant water and sanitation donor organizations - invests the majority of its budget on improving sanitation accessibility. The World Health Organization and the United Nations Millennium Development Goals also prioritize sanitation accessibility. However, in Bangladesh, water quality must be given greater attention. As the nation's most prevalent diarrheal disease, cholera outbreaks result in incalculable lost wages and treatment expenses, taken from the pockets of an already impoverished society. Bangladesh cannot afford cholera; prevention is the only sustainable control option, and water quality is the most effective intervention point for Dhaka, Bangladesh.

Majumder, M. S.; Gute, D.; Faruque, A. S.

2011-12-01

382

Freeze/Thaw-Induced Embolism: Probability of Critical Bubble Formation Depends on Speed of Ice Formation  

PubMed Central

Bubble formation in the conduits of woody plants sets a challenge for uninterrupted water transportation from the soil up to the canopy. Freezing and thawing of stems has been shown to increase the number of air-filled (embolized) conduits, especially in trees with large conduit diameters. Despite numerous experimental studies, the mechanisms leading to bubble formation during freezing have not been addressed theoretically. We used classical nucleation theory and fluid mechanics to show which mechanisms are most likely to be responsible for bubble formation during freezing and what parameters determine the likelihood of the process. Our results confirm the common assumption that bubble formation during freezing is most likely due to gas segregation by ice. If xylem conduit walls are not permeable to the salts expelled by ice during the freezing process, osmotic pressures high enough for air seeding could be created. The build-up rate of segregated solutes in front of the ice-water interface depends equally on conduit diameter and freezing velocity. Therefore, bubble formation probability depends on these variables. The dependence of bubble formation probability on freezing velocity means that the experimental results obtained for cavitation threshold conduit diameters during freeze/thaw cycles depend on the experimental setup; namely sample size and cooling rate. The velocity dependence also suggests that to avoid bubble formation during freezing trees should have narrow conduits where freezing is likely to be fast (e.g., branches or outermost layer of the xylem). Avoidance of bubble formation during freezing could thus be one piece of the explanation why xylem conduit size of temperate and boreal zone trees varies quite systematically. PMID:22685446

Sevanto, Sanna; Holbrook, N. Michele; Ball, Marilyn C.

2012-01-01

383

Embolism Formation during Freezing in the Wood of Picea abies1  

PubMed Central

Freeze-thaw events can cause embolism in plant xylem. According to classical theory, gas bubbles are formed during freezing and expand during thawing. Conifers have proved to be very resistant to freeze-thaw induced embolism, because bubbles in tracheids are small and redissolve during thawing. In contrast, increasing embolism rates upon consecutive freeze-thaw events were observed that cannot be explained by the classical mechanism. In this study, embolism formation during freeze-thaw events was analyzed via ultrasonic and Cryo-scanning electron microscope techniques. Twigs of Picea abies L. Karst. were subjected to up to 120 freeze-thaw cycles during which ultrasonic acoustic emissions, xylem temperature, and diameter variations were registered. In addition, the extent and cross-sectional pattern of embolism were analyzed with staining experiments and Cryo-scanning electron microscope observations. Embolism increased with the number of freeze-thaw events in twigs previously dehydrated to a water potential of ?2.8 MPa. In these twigs, acoustic emissions were registered, while saturated twigs showed low, and totally dehydrated twigs showed no, acoustic activity. Acoustic emissions were detected only during the freezing process. This means that embolism was formed during freezing, which is in contradiction to the classical theory of freeze-thaw induced embolism. The clustered pattern of embolized tracheids in cross sections indicates that air spread from a dysfunctional tracheid to adjacent functional ones. We hypothesize that the low water potential of the growing ice front led to a decrease of the potential in nearby tracheids. This may result in freezing-induced air seeding. PMID:17041033

Mayr, Stefan; Cochard, Hervé; Améglio, Thierry; Kikuta, Silvia B.

2007-01-01

384

Aquaporins play a role in desiccation and freeze tolerance in larvae of the goldenrod gall fly, Eurosta solidaginis  

Microsoft Academic Search

SUMMARY Survival of freezing not only requires organisms to tolerate ice formation within their body, but also depends on the rapid redistribution of water and cryoprotective compounds between intra- and extracellular compartments. Aquaporins are transmembrane proteins that serve as the major pathway through which water and small uncharged solutes (e.g. glycerol) enter and leave the cell. Consequently, we examined freeze-tolerant

Benjamin N. Philip; Shu-Xia Yi; Michael A. Elnitsky; Richard E. Lee

2008-01-01

385

Changes in volatiles with the application of progressive freeze-concentration to Andes berry ( Rubus glaucus Benth)  

Microsoft Academic Search

Progressive freeze-concentration was applied to Andes berry (Rubus glaucus Benth) pulp to observe changes in the volatile composition. The effective partition constant K, the water removed and a yield parameter defined as water removed per unit of time was used to adjust the performance of the apparatus. For freeze-concentration effectiveness, an enzymatic treatment of the pulp was found to be

F. A. Ramos; J. L. Delgado; E. Bautista; A. L. Morales; C. Duque

2005-01-01

386

Heat pump with freeze-up prevention  

DOEpatents

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

Ecker, Amir L. (Dallas, TX)

1981-01-01

387

Freeze chromatography method and apparatus  

DOEpatents

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

Scott, C.D.

1987-04-16

388

Exact theory of freeze out  

E-print Network

By considering the kinetic equations for the relic particles and the bath particles supposed in thermal and chemical equilibrium in the early Universe, we show that the problem of finding the present relic abundance is exactly defined by a system of two equations, the usual Boltzmann equation and a new one previously not recognized. The analytical solution of the latter gives the abundance down to a matching temperature that can be identified with freeze out temperature $x_f=m/T_f$, while the usual Boltzmann equation is valid only for $x \\ge x_f$. The dependence of the present relic abundance on the abundance at an intermediate temperature is an exact result and not the consequence of the so called freeze out approximation. We also suggest an analytical approximation that furnishes the relic abundance accurate at the level of $1\\%-2\\%$ in the case of $S$-wave and $P$-wave scattering cross sections.

Cannoni, Mirco

2014-01-01

389

Exact theory of freeze out  

E-print Network

By considering the kinetic equations for the relic particles and the bath particles supposed in thermal and chemical equilibrium in the early Universe, we show that the problem of finding the present relic abundance is exactly defined by a system of two equations, the usual Boltzmann equation and a new one previously not recognized. The analytical solution of the latter gives the abundance down to a matching temperature that can be identified with freeze out temperature $x_f=m/T_f$, while the usual Boltzmann equation is valid only for $x \\ge x_f$. The dependence of the present relic abundance on the abundance at an intermediate temperature is an exact result and not the consequence of the so called freeze out approximation. We also suggest an analytical approximation that furnishes the relic abundance accurate at the level of $1\\%-2\\%$ in the case of $S$-wave and $P$-wave scattering cross sections.

Mirco Cannoni

2014-07-15

390

Research Spotlight: Map of lunar hydrogen points to large amounts of water ice  

NASA Astrophysics Data System (ADS)

In October 2009, NASA's Lunar Crater Observation and Sensing Satellite (LCROSS) mission smashed into a crater on the Moon and confirmed previous studies that suggested that water ice existed on the Moon. To learn more about lunar water, scientists are examining the abundance and distribution of hydrogen. Hydrogen has been detected near the lunar poles, but scientists have not been certain whether this hydrogen is the form of water ice or in other compounds such as molecular hydrogen. If hydrogen exists in a volatile compound such as water, it would remain stable only in cold, permanently shaded regions such as deep craters.

Ofori, Leslie; Tretkoff, Ernie

2010-12-01

391

Effects of Micro/Nano-Scale Surface Characteristics on the Leidenfrost Point Temperature of Water  

E-print Network

In recent film boiling heat transfer studies with nanofluids, it was reported that deposition of nanoparticles on a surface significantly increases the nominal minimum heat flux (MHF) or Leidenfrost Point (LFP) temperature, ...

Hu, Lin-Wen

392

Electrochemical Surface Potential due to Classical Point Charge Models Drives Anion Adsorption to the Air-Water Interface  

SciTech Connect

Herein, we present research that suggests that the underlying physics that drive simple empirical models of anions (e.g. point charge, no polarization) to the air-water interface, with water described by SPC/E, or related partial charge models is different than when both ions and water are modeled with quantum mechanical based interactions. Specifically, we will show that the driving force of ions to the air-water interface for point charge models results from both cavitation and the negative electrochemical surface potential. We will demonstrate that we can fully characterize the role of the free energy due to the electrochemical surface potential computed from simple empirical models and its role in ionic adsorption within the context of dielectric continuum theory (DCT). Our research suggests that a significant part of the electrochemical surface potential in empirical models appears to be an artifact of the failure of point charge models in the vicinity of a broken symmetry. This work was supported by the U.S. Department of Energy‘s (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the Department of Energy by Battelle.

Baer, Marcel D.; Stern, Abraham C.; Levin, Yan; Tobias, Douglas J.; Mundy, Christopher J.

2012-06-07

393

Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water  

NASA Astrophysics Data System (ADS)

The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei, and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics method at the density functional level of theory. The general effect of zero-point motion is to distort the mean structure slightly, and to promote the extent of proton transfer with respect to classical behaviour. In a particular configuration of one sulphuric acid molecule with three waters, the range of positions explored by a proton between a sulphuric acid and a water molecule at 300 K (a broad range in contrast to the confinement suggested by geometry optimisation at 0 K) is clearly affected by the inclusion of zero point motion, and similar effects are observed for other configurations.

Stinson, Jake L.; Kathmann, Shawn M.; Ford, Ian J.

2014-01-01

394

Cloud Point Extraction of Bisphenol A from Water Utilizing Cationic Surfactant Aliquat 336  

Microsoft Academic Search

In this study, cloud-point extraction (CPE) using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat 336), was carried out to separate and concentrate bisphenol-A (BPA) from aqueous media. Cloud-point phase separation of Aliquat 336 at room temperature (25 °C) was induced by the addition of Na2SO4. The parameters influencing the extraction efficiency, such as concentrations of Aliquat 336 and Na2SO4, cosolvent (methanol),

Yi-Jun YU; Guan-Yong SU; Michael HW LAM; Paul KS LAM; Hong-Xia YU

2009-01-01

395

Commercial Application of Freeze Crystallization  

E-print Network

Comparison The curve for evaporation represenls the installed cost for a multiple effecl, steam driven system. Our cost estimates indicate Ihe total installed capital cost for a mechanical vapor recompression unit would be somewhat higher. We expect... will lower substantially in future generation designs, perhaps even approaching the cost of mechanical vapor recompression evaporation. POWER CONSUMPTION An adherent advantage of freeze crystallization is the low phase change energy required...

Gorgol, R. G.

396

Infrared Monitoring of Interlayer Water in Stacks of Purple Membranes†  

PubMed Central

The thermodynamic behavior of films of hydrated purple membranes from Halobacterium salinarum and the water confined in it was studied by FTIR spectroscopy in the 180–280 K range. Unlike bulk water, water in the thin layers sandwiched between the biological membranes does not freeze at 273 K but will be supercooled to ~256 K. The melting point is unaffected, leading to hysteresis between 250 and 273 K. In its heating branch a gradually increasing light-scattering by ice is observed with rate-limiting kinetics of tens of minutes. IR spectra decomposition provided extinction coefficients for the confined water vibrational bands and their changes upon freezing. Due to the hysteresis, at any given temperature in the 255–270 K range the inter-bilayer water could be either liquid or frozen, depending on thermal history. We find that this difference affects the dynamics of the bacteriorhodopsin photocycle in the hysteresis range: the decay of the M and N states and the redistribution between them are different depending on whether or not the water was initially pre-cooled to below the freezing point. However, freezing of inter-bilayer water does block the M to N transition. Unlike the water, the purple membrane lipids do not undergo any IR-detectable phase transition in the 180–280 K range. PMID:19192202

Dioumaev, Andrei K.; Lanyi, Janos K

2009-01-01

397

Biopolymer-reinforced synthetic granular nanocomposites for affordable point-of-use water purification  

PubMed Central

Creation of affordable materials for constant release of silver ions in water is one of the most promising ways to provide microbially safe drinking water for all. Combining the capacity of diverse nanocomposites to scavenge toxic species such as arsenic, lead, and other contaminants along with the above capability can result in affordable, all-inclusive drinking water purifiers that can function without electricity. The critical problem in achieving this is the synthesis of stable materials that can release silver ions continuously in the presence of complex species usually present in drinking water that deposit and cause scaling on nanomaterial surfaces. Here we show that such constant release materials can be synthesized in a simple and effective fashion in water itself without the use of electrical power. The nanocomposite exhibits river sand-like properties, such as higher shear strength in loose and wet forms. These materials have been used to develop an affordable water purifier to deliver clean drinking water at US $2.5/y per family. The ability to prepare nanostructured compositions at near ambient temperature has wide relevance for adsorption-based water purification. PMID:23650396

Sankar, Mohan Udhaya; Aigal, Sahaja; Maliyekkal, Shihabudheen M.; Chaudhary, Amrita; Anshup; Kumar, Avula Anil; Chaudhari, Kamalesh; Pradeep, Thalappil

2013-01-01

398

COMPARATIVE ANALYSIS OF THREE SUSTAINABLE POINT OF USE DRINKING WATER TREATMENT TECHNOLOGIES FOR DEVELOPING NATIONS  

EPA Science Inventory

More than 1 billion people in the developing world lack access to safe, reliable sources of drinking water. Unsafe water takes a toll not only on human health but also on individuals’ economic productivity. Illness from waterborne disease robs people of time and...

399

POINT-OF-ENTRY DRINKING WATER TREATMENT SYSTEMS FOR SUPERFUND APPLICATIONS  

EPA Science Inventory

The U.S. Environmental Protection AGency (EPA) and State Superfund agencies need a technical assistance manualto assist their personnel in the selection of an effective drinking water treatment system for aindividualhouseholds in areas whre the drinking water has been adversely a...

400

Maple Sap Uptake, Exudation, and Pressure Changes Correlated with Freezing Exotherms and Thawing Endotherms 1  

PubMed Central

Sap flow rates and sap pressure changes were measured in dormant sugar maple trees (Acer saccharum Marsh.). In the forest, sap flow rates and pressure changes were measured from tap holes drilled into tree trunks in mature trees and sap flow rates were measured from the base of excised branches. Excised branches were also brought into the laboratory where air temperature could be carefully controlled in a refrigerated box and sap flow rates and sap pressures were measured from the cut base of the branches. Under both forest and laboratory conditions, sap uptake occurred as the wood temperature declined but much more rapid sap uptake correlated with the onset of the freezing exotherm. When sap pressures were measured under conditions of negligible volume displacement, the sap pressure rapidly fell to ?60 to ?80 kilopascals at the start of the freezing exotherm. The volume of water uptake and the rate of uptake depended on the rate of freezing. A slow freezing rate correlated with a large volume of water uptake, a fast freezing rate induced a smaller volume of water uptake. The volume of water uptake ranged from 0.02 to 0.055 grams water per gram dry weight of sapwood. The volume of water exuded after thawing was usually less than the volume of uptake so that after several freezing and thawing cycles the sapwood water content increased from 0.7 to 0.8 grams water per gram dry weight. These results are discussed in terms of a physical model of the mechanism of maple sap uptake and exudation first proposed by P. E. R. O'Malley. The proposed mechanism of sap uptake is by vapor distillation in air filled wood fiber lumina during the freezing of minor branches. Gravity and pressurized air bubbles (compressed during freezing) cause sap flow from the canopy down the tree after the thaw. PMID:16663208

Tyree, Melvin T.

1983-01-01

401

Freeze-cast hydroxyapatite scaffolds for bone tissue engineering applications.  

PubMed

Freeze casting of aqueous suspensions was investigated as a method for preparing porous hydroxyapatite (HA) scaffolds for eventual application to bone tissue engineering. Suspensions of HA particles (10-20 volume percent) were frozen unidirectionally in a cylindrical mold placed on a cold steel substrate (-20 degrees C). After sublimation of the ice, sintering for 3 h at 1350 degrees C produced constructs with dense HA lamellae, with porosity of approximately 50%, and inter-lamellar pore widths of 5-30 microm. These constructs had compressive strengths of 12 +/- 1 MPa and 5 +/- 1 MPa in the directions parallel and perpendicular to the freezing direction, respectively. Manipulation of the microstructure was achieved by modifying the solvent composition of the suspension used for freeze casting. The use of water-glycerol mixtures (20 wt% glycerol) resulted in the production of constructs with finer pores (1-10 microm) and a larger number of dendritic growth connecting the HA lamellae, and higher strength. On the other hand, the use of water-dioxane mixtures (60 wt% dioxane) resulted in a cellular-type microstructure with larger pores (90-110 microm). The mechanical response showed high strain tolerance (5-10% at the maximum stress), high strain for failure (>20%) and sensitivity to the loading rate. The favorable mechanical behavior of the porous constructs, coupled with the ability to modify their microstructure, indicates the potential of the present freeze casting route for the production of porous scaffolds for bone tissue engineering. PMID:18458369

Fu, Qiang; Rahaman, Mohamed N; Dogan, Fatih; Bal, B Sonny

2008-06-01

402

[Temporal and spatial variation of non-point source nitrogen in surface water in urban agricultural region of Shanghai].  

PubMed

To know the temporal and spatial variation characteristics of non-point source nitrogen in surface water in urban agricultural region, and reveal the effect of non-point source nitrogen pollution on the quality of surface water, the contents of total nitrogen and inorganic nitrogen species in surface water were continuously monitored in Orchard Village, Nanhui District, Shanghai. The results were obtained as follows: (1) Spatial distribution of nitrogen in surface water is affected by hydrological periods and land use type. Mass concentration of nitrate nitrogen (NN) is high and that of ammonium nitrogen (AN) is low in surface water affected by the orchard, and the discrepancy of nitrogen concentration is high in wet season and low in dry season. Mass concentrations of NN and AN in surface water affected by residential region and factories show little difference, and the discrepancy of nitrogen concentration is high both in wet season and in dry season. (2) Winter and summer monsoons may affect the spatial distribution of nitrogen in surface water in the studied area. (3) Spatial variation of total nitrogen (TN), NN and AN is the highest in spring rain period, and it is higher in plum rain period and winter brief rain period than that in autumn rain period and summer brief rain period. Nitrite nitrogen (SNN) shows contrary spatial variation. (4) Dissolved organic nitrogen (DON, mass fraction in TN is 76.1%) is the main species in surface water in orchard region in May, while the dissolved inorganic nitrogen (DIN, mass fraction in TN is 83.2%) in other months. (5) The temporal variation of NN in orchard region is higher than that in residential region, while that of AN and TN in residential region is higher than that in orchard region. PMID:22624371

Wang, Nan; Mao, Liang; Huang, Hai-Bo; Zhang, Jin-Zhong; Zhou, Pei

2012-03-01

403

A simple and flexible device for housing water monitoring sensors at point discharges  

NASA Astrophysics Data System (ADS)

The Water Monitoring Enclosure (WME) provides a simple and flexible housing for measuring many types of water parameters (physical, chemical, or biological). The WME ensures a minimum water level to allow the devices to be continuously inundated even during periods when there is no flow entering the enclosure. The limited diameter of the inflow pipe and water volume in the WME buffers the flow velocity from dramatic changes. The device ensures that the sediment entering the enclosure from the inflow will be conveyed through the enclosure with minimal sediment accumulation. The device is powered purely from natural hydraulic forces, so it requires no power source, and requires little additional maintenance beyond occasional cleaning. If desired, the WME can also measure discharge entering the device through additional modifications. Water samples were taken throughout the year to validate the effectiveness of the WME. The differences of the receiving water to the water in the WME for all parameters were below the laboratory analysis standard error. Two design limitations were found during the assessment period. First, if the receiving water has a very low sustained discharge (< 0.04 l/s) and a high fine sediment load (> 100 mg/l) then the frequency of the flushings are not capable of continuously removing the sediment and a gradual accumulation of sediment of up to 2 cm per week can occur. A smaller volume of water within the WME would reduce the accumulated sediment due to very low discharges from an increased frequency of the flushings. Second, precipitated chemical solids can cause the mechanism to seize if not regularly cleaned.

Exner-Kittridge, M.; Niederreiter, R.; Eder, A.

2012-04-01

404

Dispersion inversion of electromagnetic pulse propagation within freezing and thawing soil waveguides  

NASA Astrophysics Data System (ADS)

Freeze and thaw processes are important components in characterizing glacial, periglacial and frozen ground environments, and hence the response of cryospheric regions to climate change. High-frequency ground-penetrating radar is particularly well suited for monitoring the freezing and thawing processes within the shallow subsurface (i.e., < 1 m depth) due to its non-invasive nature and its sensitivity to the liquid water component in soil. The freezing of moist soil and thawing of frozen soil induce leaky and low-velocity waveguides, respectively. Within these waveguide layers, the internally reflected radar energy produces interfering multiples that appear as a package of dispersed waves. Here, we present a new method for characterizing very shallow freeze and thaw processes, in which the waveguide properties are obtained by inverting the observed dispersion curves. This new method can non-invasively monitor freezing and thawing processes in a wide range of glacial, periglacial and frozen ground studies.

van der Kruk, J.; Steelman, C. M.; Endres, A. L.; Vereecken, H.

2009-09-01

405

QSPR models of boiling point, octanol–water partition coefficient and retention time index of polycyclic aromatic hydrocarbons  

Microsoft Academic Search

A Quantitative Structure–Property Relationship (QSPR) analysis and study of polycyclic aromatic hydrocarbons (PAHs) is presented. Three physicochemical properties related to their environmental impact are studied: boiling point (bp), octanol–water partition coefficient (logKow) and retention time index (RI) for reversed-phase liquid chromatography analysis. The geometry of all PAHs were optimized by the semi-empirical method AM1 and used to calculate thermodynamic, electronic,

Fabiana Alves de Lima Ribeiro; Márcia Miguel Castro Ferreira

2003-01-01

406

Determination of trace elements in water samples by ultrasonic nebulization inductively coupled plasma mass spectrometry after cloud point extraction  

Microsoft Academic Search

A preconcentration method for low concentrations of Ag, As, Au, Cd, Cu, Pb and Se in water, using cloud point extraction is proposed. The analytes in the initial aqueous solution, acidified with hydrochloric acid, are complexed with ammonium O,O-diethyl-dithiophosphate, and 0.05% m\\/v Triton X-114 is added as surfactant. The complexation allows the separation of the analytes from alkali, alkaline earth

Márcia Andreia Mesquita da Silva; Vera Lúcia Azzolin Frescura; Adilson José Curtius

2000-01-01

407

COMPARISON OF MULTIPLE POINT AND COMPOSITE SAMPLING FOR THE PURPOSE OF MONITORING BATHING WATER QUALITY  

EPA Science Inventory

The USEPA Beaches Environmental Assessment and Coastal Health Act (BEACH Act) requires states to develop monitoring and notification programs for recreational waters using approved bacterial indicators. Implementation of an appropriate monitoring program can, under some circumsta...

408

Availability of fresh ground water, Montauk Point area, Suffolk County, Long Island, New York  

USGS Publications Warehouse

Ground water is the only source of supply at the Montauk Air Force Station n eastern Suffolk County. The water is contained in the upper 200 feet of deposits of late Pleistocene age, which are broadly divided into an upper unit of undifferentiated till and stratified drift and a lower unit of stratified drift. Fresh water in the principal aquifer, which is in the lower unit, is a lens-shaped body, which lies above salty water containing as much as 11,300 ppm of chloride. The fresh water is under artesian pressure and has a head ranging from about sea level to 3.5 feet above sea level. Pumping rates of 50 to 100 gpm cause salty water to move toward the. supply wells from below. The optimum pumping rate of most wells is about 30 gpm. New wells should be drilled as remote as possible from existing wells, and the well screens should be set as high above the zone of diffusion as the deposits permit.

Perlmutter, Nathaniel Matthew; DeLuca, Frank A.

1963-01-01

409

Molecular analysis of point-of-use municipal drinking water microbiology.  

PubMed

Little is known about the nature of the microbiology in tap waters delivered to consumers via public drinking water distribution systems (DWDSs). In order to establish a broader understanding of the microbial complexity of public drinking waters we sampled tap water from seventeen different cities between the headwaters of the Arkansas River and the mouth of the Mississippi River and determined the bacterial compositions by pyrosequencing small subunit rRNA genes. Nearly 98% of sequences observed among all systems fell into only 5 phyla: Proteobacteria (35%), Cyanobacteria (29%, including chloroplasts), Actinobacteria (24%, of which 85% were Mycobacterium spp.), Firmicutes (6%), and Bacteroidetes (3.4%). The genus Mycobacterium was the most abundant taxon in the dataset, detected in 56 of 63 samples (16 of 17 cities). Among the more rare phylotypes, considerable variation was observed between systems, and was sometimes associated with the type of source water, the type of disinfectant, or the concentration of the environmental pollutant nitrate. Abundant taxa (excepting Cyanobacteria and chloroplasts) were generally similar from system to system, however, regardless of source water type or local land use. The observed similarity among the abundant taxa between systems may be a consequence of the selective influence of chlorine-based disinfection and the common local environments of DWDS and premise plumbing pipes. PMID:24333849

Holinger, Eric P; Ross, Kimberly A; Robertson, Charles E; Stevens, Mark J; Harris, J Kirk; Pace, Norman R

2014-02-01

410

Control of glycerol production by rainbow smelt ( Osmerus mordax) to provide freeze resistance and allow foraging at low winter temperatures  

Microsoft Academic Search

The rainbow smelt (Osmerus mordax) is a small anadromous fish that actively feeds under the ice at temperatures as low as the freeze point of seawater. Freezing is avoided through the production of both non-colligative antifreeze protein (AFP) and glycerol that acts in a colligative manner. Glycerol is constantly lost across the gills and skin, thus glycerol production must continue

William R. Driedzic; K. Vanya Ewart

2004-01-01

411

Influence of freezing temperatures on a cactus, Coryphantha vivipara  

Microsoft Academic Search

Coryphantha vivipara (Nutt.) Britton & Rose var. deserti (Engelm.) W.T. Marshall (Cactaceae) survived snow and tissue temperatures of-12°C in southern Nevada. However, the freezing point depression of the cell sap was only about 0.9°C. When the nocturnal air temperature in the laboratory was reduced from 10°C to-10°C for one night, the optimum temperature for CO2 uptake shifted from 10°C to

Park S. Nobel

1981-01-01

412

NonPoint Source Water Pollution in China: Current Status and Future Prospects  

Microsoft Academic Search

The pollution impacts of different types of non-point source pollution (NSP) were identified on a large scale in the lower Great Lakes of North America in the 1970s, beginning with the eutrophication crisis in these lakes and subsequently expanding to toxic substances and endocrine disrupting substances. Since then, there has developed a large knowledge base on this subject. Especially in

Edwin D. Ongley

2004-01-01

413

Freeze-induced expression of a novel gene, fr47, in the liver of the freeze-tolerant wood frog, Rana sylvatica.  

PubMed

The ability to endure the freezing of body fluids is well developed as an adaptation for winter survival in several species of woodland frogs. Recently, the mechanisms supporting natural freeze tolerance have been shown to include the expression of novel genes. One such novel gene, fr47, codes for a 390-amino acid protein present in the livers of freeze-tolerant anurans (Rana sylvatica, Pseudacris crucifer, Hyla versicolor) but not in freeze-intolerant species (Rana pipiens, Scaphiopus couchii). Regulatory influences on gene and protein expression were investigated using R. sylvatica. Northern blot analysis showed that transcript levels were increased following 24 h of freezing (5.1-fold), 24 h of anoxia exposure (6.4-fold), or the loss of 20% of total body water (2.7-fold). Immunoblotting with anti-FR47 antibody indicated that protein levels increased during freezing and thawing, but decreased somewhat during anoxia or dehydration exposure, although rebounding during recovery. These results suggest that (i) FR47 function is important for freeze survival, and (ii) that control at the protein level may be exerted posttranscriptionally. Finally, assessment of putative signal transduction pathways regulating fr47 gene expression, via in vitro incubations of liver slices, indicated the involvement of a protein kinase C-mediated pathway. PMID:12531477

McNally, J Dayre; Sturgeon, Christopher M; Storey, Kenneth B

2003-01-27

414

Clathrate hydrates in frozen confections : formation by carbon dioxide flash freezing and behavior during distribution and consumption  

E-print Network

Carbonated frozen foods are not common on the market due to the limited liquid water available to dissolve CO? . CO? clathrate hydrates can change this because CO? is trapped in crystalline water. The CO? flash-freezing ...

Peters, Teresa Baker, 1981-

2009-01-01

415

Ultrafast microfluidic mixer and freeze-quenching device.  

PubMed

The freeze-quenching technique is extremely useful for trapping meta-stable intermediates populated during fast chemical or biochemical reactions. The application of this technique, however, is limited by the long mixing time of conventional solution mixers and the slow freezing time of cryogenic fluids. To overcome these problems, we have designed and tested a novel microfluidic silicon mixer equipped with a new freeze-quenching device, with which reactions can be followed down to 50 micros. In the microfluidic silicon mixer, seven 10-microm-diameter vertical pillars are arranged perpendicular to the flow direction and in a staggered fashion in the 450-pL mixing chamber to enhance turbulent mixing. The mixed-solution jet, with a cross section of 10 microm x 100 microm, exits from the microfluidic silicon mixer with a linear flow velocity of 20 m/s. It instantaneously freezes on one of two rotating copper wheels maintained at 77 K and is subsequently ground into an ultrafine powder. The ultrafine frozen powder exhibits excellent spectral quality and high packing factor and can be readily transferred between spectroscopic observation cells. The microfluidic mixer was tested by the reaction between azide and myoglobin at pH 5.0. It was found that complete mixing was achieved within the mixing dead time of the mixer (20 micros), and the first observable point for this coupled device was determined to be 50 micros, which is approximately 2 orders of magnitude faster than commercially available instruments. PMID:14710815

Lin, Yu; Gerfen, Gary J; Rousseau, Denis L; Yeh, Syun-Ru

2003-10-15

416

Liquid-liquid phase transition model incorporating evidence for ferroelectric state near the lambda-point anomaly in supercooled water  

E-print Network

We propose a unified model combining the first-order liquid-liquid and the second-order ferroelectric phase transitions models and explaining various features of the $\\lambda$-point of liquid water within a single theoretical framework. It becomes clear within the proposed model that not only does the long-range dipole-dipole interaction of water molecules yield a large value of dielectric constant $\\epsilon$ at room temperatures, our analysis shows that the large dipole moment of the water molecules also leads to a ferroelectric phase transition at a temperature close to the lambda-point. Our more refined model suggests that the phase transition occurs only in the low density component of the liquid and is the origin of the singularity of the dielectric constant recently observed in experiments with supercooled liquid water at temperature T~233K. This combined model agrees well with nearly every available set of experiments and explains most of the well-known and even recently obtained results of MD simulations.

Peter O. Fedichev; Leonid I. Menshikov

2012-01-30

417

Metabolic Activity of Permafrost Bacteria below the Freezing Point  

Microsoft Academic Search

Metabolic activity was measured in the laboratory at temperatures between 5 and 220°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,

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

2000-01-01

418

Traditional and Molecular Analyses for Fecal Indicator Bacteria in Non-point Source Subtropical Recreational Marine Waters  

PubMed Central

The use of enterococci as the primary fecal indicator bacteria (FIB) for the determination of recreational water safety has been questioned, particularly in sub/tropical marine waters without known point sources of sewage. Alternative FIB (such as the Bacteroidales group) and alternative measurement methods (such as rapid molecular testing) have been proposed to supplement or replace current marine water quality testing methods which require culturing enterococci. Moreover, environmental parameters have also been proposed to supplement current monitoring programs. The objective of this study was to evaluate the health risks to humans from exposure to subtropical recreational marine waters with no known point source. The study reported symptoms between one set of human subjects randomly assigned to marine water exposure with intensive environmental monitoring compared with other subjects who did not have exposure. In addition, illness outcomes among the exposed bathers were compared to levels of traditional and alternative FIB (as measured by culture-based and molecular-based methods), and compared to easily measured environmental parameters. Results demonstrated an increase in self-reported gastrointestinal, respiratory and skin illnesses among bathers vs. non-bathers. Among the bathers, a dose-response relationship by logistic regression modeling was observed for skin illness, where illness was positively related to enterococci enumeration by membrane filtration (odds ratio =1.46 [95% confidence interval=0.97-2.21] per increasing log10 unit of enterococci exposure) and positively related to 24 hour antecedent rain fall (1.04 [1.01 – 1.07] per increasing millimeters of rain). Acute febrile respiratory illness was inversely related to water temperature (0.74 [0.56-0.98] per increasing degree of water temperature). There were no significant dose response relationships between report of human illness and any of the other FIB or environmental measures. Therefore, for non-point source subtropical recreational marine waters, this study suggests that humans may be at increased risk of reported illness, and that the currently recommended and investigational FIB may not track gastrointestinal illness under these conditions; the relationship between other human illness and environmental measures is less clear. PMID:20605185

Sinigalliano, Christopher D.; Fleisher, Jay M.; Gidley, Maribeth L.; Solo-Gabriele, Helena M.; Shibata, Tomoyuki; Plano, Lisa R.W.; Elmir, Samir M.; Wanless, David; Bartkowiak, Jakub; Boiteau, Rene; Withum, Kelly; Abdelzaher, Amir M.; He, Guoqing; Ortega, Cristina; Zhu, Xiaofang; Wright, Mary E.; Kish, Jonathan; Hollenbeck, Julie; Scott, Troy; Backer, Lorraine C.; Fleming, Lora E.

2010-01-01

419

Transverse freezing of thin liquid films  

NASA Astrophysics Data System (ADS)

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

Beerman, Michael

420

From a water resource to a point pollution source: the daily journey of a coastal urban stream.  

PubMed

The aim of this study was to understand how a stream ecosystem that flows from its fountainhead to its mouth inside a city, changes from a water resource to a point pollution source. A multidisciplinary descriptive approach was adopted, including the short-term temporal and spatial determination of physical, chemical, biological and ecotoxicological variables. Results showed that water quality rapidly decreases with increasing urbanization, leading the system to acquire raw sewage attributes even in the first hundred meters after the fountainheads. Despite the tidal circulation near the stream mouth being restricted by shallowness, some improvement of the water quality was detected in this area. The multidisciplinary evaluation showed to be useful for obtaining a more realistic understanding of the stream degradation process, and to forecast restoration and mitigation measures. PMID:18278310

Rörig, L R; Tundisi, J G; Schettini, C A F; Pereira-Filho, J; Menezes, J T; Almeida, T C M; Urban, S R; Radetski, C M; Sperb, R C; Stramosk, C A; Macedo, R S; Castro-Silva, M A; Perez, J A A

2007-11-01

421

A spatial model to aggregate point-source and nonpoint-source water-quality data for large areas  

USGS Publications Warehouse

More objective and consistent methods are needed to assess water quality for large areas. A spatial model, one that capitalizes on the topologic relationships among spatial entities, to aggregate pollution sources from upstream drainage areas is described that can be implemented on land surfaces having heterogeneous water-pollution effects. An infrastructure of stream networks and drainage basins, derived from 1:250,000-scale digital-elevation models, define the hydrologic system in this spatial model. The spatial relationships between point- and nonpoint pollution sources and measurement locations are referenced to the hydrologic infrastructure with the aid of a geographic information system. A maximum-branching algorithm has been developed to simulate the effects of distance from a pollutant source to an arbitrary downstream location, a function traditionally employed in deterministic water quality models. ?? 1992.

White, D. A.; Smith, R. A.; Price, C. V.; Alexander, R. B.; Robinson, K. W.

1992-01-01

422

Water access points and hydration pathways in CLC H+/Cl? transporters  

PubMed Central

CLC transporters catalyze transmembrane exchange of chloride for protons. Although a putative pathway for Cl? has been established, the pathway of H+ translocation remains obscure. Through a highly concerted computational and experimental approach, we characterize microscopic details essential to understanding H+-translocation. An extended (0.4 µs) equilibrium molecular dynamics simulation of membrane-embedded, dimeric ClC-ec1, a CLC from Escherichia coli, reveals transient but frequent hydration of the central hydrophobic region by water molecules from the intracellular bulk phase via the interface between the two subunits. We characterize a portal region lined by E202, E203, and A404 as the main gateway for hydration. Supporting this mechanism, site-specific mutagenesis experiments show that ClC-ec1 ion transport rates decrease as the size of the portal residue at position 404 is increased. Beyond the portal, water wires form spontaneously and repeatedly to span the 15-Å hydrophobic region between the two known H+ transport sites [E148 (Gluex) and E203 (Gluin)]. Our finding that the formation of these water wires requires the presence of Cl? explains the previously mystifying fact that Cl? occupancy correlates with the ability to transport protons. To further validate the idea that these water wires are central to the H+ transport mechanism, we identified I109 as the residue that exhibits the greatest conformational coupling to water wire formation and experimentally tested the effects of mutating this residue. The results, by providing a detailed microscopic view of the dynamics of water wire formation and confirming the involvement of specific protein residues, offer a mechanism for the coupled transport of H+ and Cl? ions in CLC transporters. PMID:24379362

Han, Wei; Cheng, Ricky C.; Maduke, Merritt C.; Tajkhorshid, Emad

2014-01-01

423

Micro- and Nano- Porous Adsorptive Materials for Removal of Contaminants from Water at Point-of-Use  

NASA Astrophysics Data System (ADS)

Water is food, a basic human need and a fundamental human right, yet hundreds of millions of people around the world do not have access to clean drinking water. As a result, about 5000 people die each day from preventable water borne diseases. This dissertation presents the results of experimental and theoretical studies on three different types of porous materials that were developed for the removal of contaminants from water at point of use (household level). First, three compositionally distinct porous ceramic water filters (CWFs) were made from a mixture of redart clay and sieved woodchips and processed into frustum shape. The filters were tested for their flow characteristics and bacteria filtration efficiencies. Since, the CWFs are made from brittle materials, and may fail during processing, transportation and usage, the mechanical and physical properties of the porous clays were characterized, and used in modeling designed to provide new insights for the design of filter geometries. The mechanical/physical properties that were characterized include: compressive strength, flexural strength, facture toughness and resistance curve behavior, keeping in mind the anisotropic nature of the filter structure. The measured flow characteristics and mechanical/physical properties were then related to the underlying porosity and characteristic pore size. In an effort to quantify the adhesive interactions associated with filtration phenomena, atomic force microscopy (AFM) was used to measure the adhesion between bi-material pairs that are relevant to point-of-use ceramic water filters. The force microscopy measurements of pull-off force and adhesion energy were used to rank the adhesive interactions. Similarly, the adsorption of fluoride to hydroxyapatite-doped redart clay was studied using composites of redart clay and hydroxyapatite (C-HA). The removal of fluoride from water was explored by carrying out adsorption experiments on C-HA adsorbents with different ratios of clay to hydroxyapatite (and sintered at different temperatures). The overall adsorption was controlled using water with varying fluoride concentrations and adsorbent-adsorbate contact times. Prototype frustum-shaped C-HA filters were then fabricated and shown to remove both fluoride and E.coli bacteria from water. Finally, "buckyweb", which is a foam comprising carbon nanotubes and graphene was made via thermal ablation of graphite, and tested for its deflouridation capacity. Defluoridation was studied in terms of concentration of fluoride, contact time and pH. The structure and adsorption characteristics of buckyweb foams were elucidated via energy dispersive x-ray spectroscopy, transmission electron microscopy and scanning transmission electron microscopy. The implications of the results were then explored for potential applications in water filtration.

Yakub, Ismaiel

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Predicting Freezing for Some Repulsive Potentials  

SciTech Connect

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

Khrapak, S. A.; Morfill, G. E. [Max-Planck-Institut fuer extraterrestrische Physik, D-85741 Garching (Germany)

2009-12-18

425

UV-TUBE DESIGN CONCEPT FOR SUSTAINABLE, POINT-OF-USE WATER DISINFECTION  

EPA Science Inventory

The 2002 World Health Organization (WHO) report on worldwide mortality indicates that waterborne illnesses associated with unsafe drinking water and poor sanitation are still a major cause of death in the developing world. Although a variety of methods exist for treating dr...

426