THE FREEZING POINTS OF HIGH PURITY METALS AS PRECISION TEMPERATURE STANDARDS: II. AN INVESTIGATION OF THE FREEZING TEMPERATURES OF ZINC, CADMIUM, AND TIN

1957 ◽  
Vol 35 (9) ◽  
pp. 1086-1106 ◽  
Author(s):  
E. H. McLaren
Keyword(s):  
High Purity ◽  
Freezing Temperature ◽  
Pressure Effects ◽  
Platinum Resistance ◽  
Long Term Stability ◽  
Melting Temperatures ◽  
Three Samples ◽  
Zinc Cadmium ◽  
Precision Temperature ◽  
Freezing Temperatures

An investigation of freezing and melting temperatures with platinum resistance thermometry on high purity zinc, cadmium, and tin has been carried out. Using appropriate techniques, plateaus of essentially constant (< ±0.0001 °C.) temperature with durations of over 1 hour are readily obtained on the cooling curves of these metals. For series of freezes on particular samples, the standard deviations of the respective plateau temperatures were found to be of the order of ±0.0002 °C. It was not possible to distinguish among the plateau temperatures of three samples selected from different distillation batches of New Jersey S.P. zinc. Evidence is presented on the long term stability ([Formula: see text] years) of the plateau freezing temperature of S.P. zinc determined with six standard thermometers. The pressure effects on the freezing temperatures were found to be 0.0043 °C, 0.0062 °C, and 0.0033 °C. per atmosphere for zinc, cadmium, and tin respectively.Thermal analysis of these high purity metals reveals alloy structures and other features associated with nucleation, coring, and annealing phenomena; typical thermal curves are shown.

THE FREEZING POINTS OF HIGH PURITY METALS AS PRECISION TEMPERATURE STANDARDS: IV. INDIUM: THERMAL ANALYSES ON THREE GRADES OF CADMIUM

1958 ◽  
Vol 36 (9) ◽  
pp. 1131-1147 ◽  
Author(s):  
E. H. McLaren
Keyword(s):  
High Purity ◽  
Pressure Effect ◽  
Thermal Analyses ◽  
Freezing Temperature ◽  
Liquidus Point ◽  
Characteristic Structure ◽  
Melting Temperatures ◽  
Two Samples ◽  
Different Types ◽  
Precision Temperature

An investigation of the freezing and melting temperatures of a sample of high purity indium (Cominco 99.999+ %) has been made. Plateaux of essentially constant (< ± 0.0001 °C) temperature with durations for over 1 hour are readily obtained on the cooling curves of induced freezes on this metal. The standard deviation of the plateau temperature (liquidus point) from a series of 24 induced freezes was ±0.0001 °C. The pressure effect on the freezing temperature of indium was found to be 0.0049 °C for 1 atm. Alloy melting ranges were measured following different types of freezing.An extensive intercomparison of liquidus points and alloy melting ranges has been made on a sample of 99.99% cadmium and two samples of 99.999+ % cadmium from different suppliers. The liquidus points of the high purity samples were indistinguishable using precision resistance thermometry but one sample melted over a slightly smaller range of temperature than the other. Both these samples showed minor arrests on melting curves after induced freezing and detailed analyses of the melting contours after various types of freezing indicated some evidence of characteristic structure inside a range of 0.002 °C.

THE FREEZING POINTS OF HIGH PURITY METALS AS PRECISION TEMPERATURE STANDARDS: VI. THERMAL ANALYSES ON FIVE SAMPLES OF LEAD WITH PURITIES GREATER THAN 99.999+%

1960 ◽  
Vol 38 (5) ◽  
pp. 577-587 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
High Purity ◽  
Thermal Analyses ◽  
Solidus Temperature ◽  
Freezing Temperature ◽  
Liquidus Point ◽  
Pure Lead ◽  
Melting Temperatures ◽  
A Value ◽  
Precision Temperature ◽  
Selection Of

An investigation has been made of the freezing and melting temperatures of five samples of high purity lead (supplier's analyzed impurity contents < 0.7 to < 4 p.p.m.) including zone refined metal. Using the induced freezing technique, plateaux of essentially constant (< ±0.0001 °C) temperature with durations of over 1 hour are readily obtained on the cooling curves of these samples. A standard deviation in plateau temperature (liquidus point) of ±0.0001 °C was obtained from a series of 30 induced freezes on a particular sample. The pressure effect on the freezing temperature of lead was found to be 0.0080 °C for 1 atmosphere. A value of 327.426 °C (Int. 1948) was determined for the standard liquidus point of pure lead.The liquidus points of the samples were intercompared with a precision of about 0.0002 °C, and alloy melting ranges were examined following different types of freezing with and without overnight anneals near the solidus temperature. Alloy melting range parameters were found to be useful in the selection of the samples of highest purity and at the same time showed that an uncertainty of 0.002 °C in the above value of the liquidus point of pure lead may exist because of residual impurity contents in the purest samples that were examined.

THE FREEZING POINTS OF HIGH-PURITY METALS AS PRECISION TEMPERATURE STANDARDS: VII. THERMAL ANALYSES ON SEVEN SAMPLES OF BISMUTH WITH PURITIES GREATER THAN 99.999 + %

1963 ◽  
Vol 41 (1) ◽  
pp. 95-112 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
High Purity ◽  
Thermal Analyses ◽  
Freezing Temperature ◽  
Liquidus Point ◽  
Melting Temperatures ◽  
A Value ◽  
Precision Temperature ◽  
Selection Of ◽  
Water Triple Point Cells ◽  
Water Triple Point

An investigation has been made of the freezing and melting temperatures of seven samples of high-purity bismuth (analyzed impurity contents <0.5 to 7 ppm) including zone-refined metal. Using a controlled outside nucleation technique, freezing curves having plateaux of essentially constant (< ±0.0001 °C) temperature with long durations are readily obtained. A standard deviation in plateau temperature (liquidus point) of ±0.00025 °C was obtained from a series of 34 freezes on a particular sample. The pressure effect on the freezing temperature of bismuth was determined as −0.0035 °C for 1 atmosphere. A value of 271.375 °C (Int. 1948) was determined for the standard liquidus point of pure bismuth.The liquidus points of the samples were intercompared with a precision of about 0.0002 °C and their alloy melting ranges were measured for selection of the purest samples. Ingot morphologies and solute redistributions during melting and freezing were investigated using decanting, quenching, and tracer techniques.Appendix I gives the results of the latest intercomparison of temperatures realized in a grid of water triple-point cells that is maintained by this laboratory for use in the precision temperature measurements. Appendix II lists the values and pressure–temperature dependencies of the liquidus points of the purest samples of Zn, Pb, Cd, Bi, Sn, and In that have been determined at this laboratory.

THE FREEZING POINTS OF HIGH PURITY METALS AS PRECISION TEMPERATURE STANDARDS: I. PRECISION MEASUREMENTS WITH STANDARD RESISTANCE THERMOMETERS

1957 ◽  
Vol 35 (1) ◽  
pp. 78-90 ◽  
Author(s):  
E. H. McLaren
Keyword(s):  
Triple Point ◽  
Cold Work ◽  
Platinum Resistance ◽  
Intrinsic Resistance ◽  
Long Term Stability ◽  
Resistance Bridge ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Precision Temperature

The techniques and difficulties encountered in measuring temperatures to the highest precision with platinum resistance thermometers are discussed. It is shown that the relative drift of the resistance coils in the Mueller resistance bridge used for these measurements is less than a part per million per year. The intrinsic resistance of a platinum thermometer is comparatively unstable, and results showing some effects of cold work and heat treatment on several thermometers are given.As each precision temperature determination involves the resistance of the thermometer at the triple point of water, extensive measurements have been carried out to obtain information on: (a) the reproducibility of temperature in particular cells, (b) the variation in temperature among cells, and (c) the long term stability of cell temperatures.The limiting uncertainties in temperature measurements due to variation in the bridge, the thermometers, and the triple point cells are each of the order of 10−4 °C.

The freezing points of high-purity metals as precision temperature standards. VIIIa. Sb: Apparatus, freezing techniques, and ingot morphology

1968 ◽  
Vol 46 (5) ◽  
pp. 369-400 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
High Purity ◽  
Pressure Effect ◽  
Auxiliary Information ◽  
Freezing Temperature ◽  
Solute Segregation ◽  
Melting Range ◽  
Liquidus Point ◽  
Tracer Techniques ◽  
Abundant Evidence ◽  
Precision Temperature

This paper describes the apparatus and the freezing techniques that have been developed to determine the liquidus points (630.55 °C) of samples of high-purity antimony to a reproducible precision of ± < 0.0005 °C. Freezing plateaux steady to ± 0.0001 °C for long (hours) durations are readily obtained on freezing curves of high-purity antimony using an outside-nucleated slow induced freezing (ONSIF) technique in a balanced three-winding inconel block furnace. The pressure effect on the freezing temperature of antimony was determined as + 0.000 85 °C for 1 atm, which corresponds to a contraction on Sb solidification of 0.98%; a contraction on freezing is supported by volumetric measurements on the shrinkage pipes in Sb ingots and by observations on decanted and quenched (during freezing) ingots that Sb dendritic solid is more dense than Sb liquid.Metallurgical studies using decanting, quenching, and tracer techniques determined the ingot morphology during freezing and melting to verify that a satisfactory control of the transforming ingot had been attained for liquidus point realizations and to provide auxiliary information on the nature of solute segregation and segregate remelting for the interpretation of alloy melting-range comparisons on several samples of high-purity antimony described in Part VIIIb of this series of papers. Abundant evidence of the fragmentation of masses of large rod dendrites and the surface recontouring of dendrite spines by recalescent remelting was found in both decanted and quenched Sb ingots: the pileup of dendritic solid in the bottom of the crucible does not preclude precise temperature determinations on ONSIF freezes.

scholarly journals Uskumru (Scomber scombrus) ve Levrek (Dicentrarchus labrax ) Kemiklerinden Jelatin Ekstraksiyonu ve Karakterizasyonu

2016 ◽  
Vol 4 (9) ◽  
pp. 728
Author(s):  
Yasemen Yanar ◽  
Mehmet Gökçin
Keyword(s):  
Moisture Content ◽  
Physicochemical Properties ◽  
High Purity ◽  
Good Yield ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Commercial Fish ◽  
Melting Temperatures ◽  
Scomber Scombrus ◽  
L Value

The aims of this study were to determine the physicochemical properties of extracted gelatins from mackerel (Scomber scombrus) and sea bass (Dicentrarchus labrax) bones and compare with those of commercial fish and bovine gelatins. The yield of gelatin obtained from the bone of mackerel and sea bass were 5.98 and 6.20%, respectively. Two extracted gelatins showed higher protein content, lower moisture content compared to both commercial gelatins, indicates that the gelatin has considerably high purity. Melting temperatures of mackerel and sea bass bone gelatins were 25.5 and 23°C, respectively. Mackerel bone gelatin was yellow in appearance and higher L* value than both commercial gelatins. It can be concluded from the present study that mackerel and sea bass bone are a prospective source to produce gelatin in good yield with desirable functional properties comparable to commercially available mammalian and fish gelatins.

Temperature gradient osmometer and anomalies in freezing temperatures

1994 ◽  
Vol 267 (6) ◽  
pp. R1646-R1652
Author(s):  
A. Arav ◽  
B. Rubinsky
Keyword(s):  
Amino Acids ◽  
Temperature Gradient ◽  
Cell Membranes ◽  
Organic Molecules ◽  
Thermal Hysteresis ◽  
Freezing Point ◽  
Freezing Temperature ◽  
New Device ◽  
Melting Temperatures ◽  
Temperature Depression

We have developed a new device that measures freezing and melting temperatures in nanoliter volume samples and can be used as a "freezing point osmometer" with a resolution many orders of magnitude greater than that of existing freezing point osmometers. Using this device we found anomalies in the depression of the freezing temperature and thermal hysteresis in aqueous solutions of hydrophilic amino acids, polyamino acids, and lectins. These anomalies would not have been possible to detect with currently used technology. The compounds that produce anomalies in freezing temperature were reported in the literature as having the ability to bind to cell membranes. This suggests a relation between a molecule's ability to bind to cell membranes and its anomalous freezing temperature depression. The new freezing point osmometer and our results could be important for studying and understanding organic molecules and their interaction with membranes and water.

The Spontaneous Freezing Temperatures of Melted Snow and of Small Water Drops

1954 ◽  
Vol 35 (2) ◽  
pp. 52-55 ◽  
Author(s):  
Harry C. Vaughan
Keyword(s):  
Drop Size ◽  
Freezing Temperature ◽  
Bulk Sample ◽  
Bulk Water ◽  
Lower Atmosphere ◽  
Obvious Effect ◽  
Small Water ◽  
Melted Snow ◽  
Freezing Temperatures ◽  
Snow Crystals

The spontaneous freezing temperatures of samples of melted snow collected at hourly intervals during several storms are reported. The freezing temperatures were found to range from −8.3 to −16.8°C. In most cases the freezing temperature remained fairly constant over periods of several hours. Gross variations in the pollution of the lower atmosphere caused no obvious effect on the observed freezing temperatures. It is suggested that the observed freezing temperatures represent the temperatures of initial formation of the snow crystals. A few experiments on the freezing temperatures of small drops were made with a technique such that all drops were formed from the same bulk sample without any danger of contamination. In all cases the freezing temperatures of the drops were well below that of the bulk water. The freezing temperature decreased with decreasing drop size but there was a relatively large variation for a given drop size.

scholarly journals Effects of storage temperature and repeated freeze–thaw cycles on stability of bovine plasma concentrations of haptoglobin and ceruloplasmin

2017 ◽  
Vol 29 (5) ◽  
pp. 738-740 ◽  
Author(s):  
Paulo G. M. A. Martins ◽  
Philipe Moriel ◽  
John D. Arthington
Keyword(s):  
Whole Blood ◽  
Storage Temperature ◽  
Plasma Concentrations ◽  
Freezing Temperature ◽  
Plasma Samples ◽  
Blood Samples ◽  
Freeze Thaw ◽  
Bovine Plasma ◽  
Whole Blood Samples ◽  
Freezing Temperatures

We evaluated the effects of storage temperature (−20 or −80°C) and handling procedure on plasma concentrations of bovine haptoglobin and ceruloplasmin. Within each temperature, whole blood samples were: centrifuged within 2 h of collection and plasma kept frozen until analysis (control); refrigerated at 4°C for 24 h before plasma harvest and freezing (24H); or plasma harvested and frozen within 2 h after collection, but then plasma samples were thawed and refrozen 1 wk (1X), 1 and 2 wk (2X), or 1, 2 and 3 wk (3X) before analyses. Haptoglobin concentrations were greatest at 24H, but similar among remaining treatments. Ceruloplasmin concentrations were not affected by the handling procedures. Storage temperature did not affect haptoglobin concentrations, but ceruloplasmin concentrations decreased when stored at −20 versus −80°C. Except for greater concentrations after 24 h storage at 4°C, haptoglobin concentrations remained stable at either freezing temperature and through freeze–thaw cycles. Ceruloplasmin concentrations decreased after 3 freeze–thaw cycles and required lower freezing temperatures to remain stable.

scholarly journals Ice nucleation efficiency of AgI: review and new insights

2016 ◽  
Vol 16 (14) ◽  
pp. 8915-8937 ◽  
Author(s):  
Claudia Marcolli ◽  
Baban Nagare ◽  
André Welti ◽  
Ulrike Lohmann
Keyword(s):  
Water Adsorption ◽  
Water Saturation ◽  
Experimental Studies ◽  
Freezing Temperature ◽  
Nucleating Agent ◽  
Ice Nucleation ◽  
Lattice Match ◽  
Complex Picture ◽  
Good Lattice ◽  
Freezing Temperatures

Abstract. AgI is one of the best-investigated ice-nucleating substances. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Theoretical and experimental studies over the last 60 years provide a complex picture of silver iodide as an ice-nucleating agent with conflicting and inconsistent results. This review compares experimental ice nucleation studies in order to analyze the factors that influence the ice nucleation ability of AgI. The following picture emerges from this analysis: the ice nucleation ability of AgI seems to be enhanced when the AgI particle is on the surface of a droplet, which is indeed the position that a particle takes when it can freely move in a droplet. The ice nucleation by particles with surfaces exposed to air depends on water adsorption. AgI surfaces seem to be most efficient at nucleating ice when they are exposed to relative humidity at or even above water saturation. For AgI particles that are completely immersed in water, the freezing temperature increases with increasing AgI surface area. Higher threshold freezing temperatures seem to correlate with improved lattice matches as can be seen for AgI–AgCl solid solutions and 3AgI·NH4I·6H2O, which have slightly better lattice matches with ice than AgI and also higher threshold freezing temperatures. However, the effect of a good lattice match is annihilated when the surfaces have charges. Also, the ice nucleation ability seems to decrease during dissolution of AgI particles. This introduces an additional history and time dependence for ice nucleation in cloud chambers with short residence times.

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