scholarly journals A NEW ABSOLUTE NOISE THERMOMETER AT LOW TEMPERATURES

1959 ◽  
Vol 37 (12) ◽  
pp. 1397-1406 ◽  
Author(s):  
H. J. Fink
Keyword(s):  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Thermal Noise ◽  
Noise Source ◽  
The Other ◽  
Liquid Oxygen ◽  
Noise Thermometer ◽  
Boiling Points ◽  
Different Temperatures

If three resistors, which are kept at different temperatures, are arranged in form of a π network and if two of the thermal noise voltages appearing across the π network are multiplied together and averaged with respect to time, then under certain conditions the correlation between those voltages can be made zero. This condition is used to calculate the temperature of one noise source provided all the resistance values and the other temperatures are known. A noise thermometer of this kind was constructed which is capable of measuring temperatures below approximately 140° K. The boiling points of liquid oxygen and liquid nitrogen were determined absolutely within 0.2%. Between 1.3° K and 4.2° K the thermometer had to be calibrated due to errors arising in the equipment and the measured temperatures were then accurate within ± 1%.

Effect of Cooling Condition after Warm Rolling on the Development of Microstructure and Texture in an ELC Steel

2005 ◽  
Vol 105 ◽  
pp. 259-264
Author(s):  
Arunansu Haldar ◽  
R.K. Ray ◽  
A.J. Khan
Keyword(s):  
Low Temperatures ◽  
Low Carbon Steel ◽  
Warm Rolling ◽  
The Other ◽  
Texture Development ◽  
Low Carbon ◽  
Deformation Bands ◽  
Cooling Conditions ◽  
Different Temperatures ◽  
Rolling Temperatures

The microstructure and texture development in an extra low carbon steel during warm rolling (~ 80%) in a single pass at four different temperatures and at two different cooling conditions were studied. The g fibre texture develops at lower warm rolling temperatures (500 °C and 600 °C) and a very weak a fibre develops at higher rolling temperatures (700 °C and 800 °C). Very little or no difference in microstructure and texture development was observed under two cooling conditions at four rolling temperatures. No significant effect of cooling rates could be found at higher temperatures of rolling due to very fast static recrystallisation after rolling which also caused the weakening of texture. On the other hand deformation bands produced at low temperatures rolling helped in forming strong g fibre textures.

Preservation of viable flexibacteria at low temperatures

1970 ◽  
Vol 16 (6) ◽  
pp. 441-444 ◽  
Author(s):  
Annika Sanfilippo ◽  
Ralph A. Lewin
Keyword(s):  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Extreme Temperature ◽  
Dimethyl Sulphoxide ◽  
The Other

Most of the 28 species (91 strains) of flexibacteria tested without additives survived after freezing in liquid nitrogen (−196 °C): they included all six Microscilla spp., all three Cytophaga spp., both of the Herpetosiphon spp. tested, Flexithrix dorotheae, and seven (most strains) of the eight species of Flexibacter spp. All but 2 of the 19 strains of Saprospira grandis, but neither of the two other tested species of Saprospira, survived freezing to −196° without additives.Incorporation of 10% glycerol before freezing permitted survival of three of the sensitive strains of Flexibacter (F. aurantiacus copepodarum, F. flexilis iolanthae, and F. giganteus), but adversely affected two other species (F. elegans and F. ruber). Incorporation of 10% dimethyl sulphoxide (DMSO) had some similar effects. Freezing to −196° with glycerol conserved viable cultures of all 19 S. grandis strains, of S. toviformis, and of 2 of the 3 strains of S. thermalis.A less extreme temperature was less satisfactory. Stored at −22°, some or all strains of 6 species died out in less than 1 week; most strains of 12 others died after a few weeks; and 7 species survived for at least 21 weeks. (The other three were not tested.)

Influence of Temperature and Rate on the Contractility of Isolated Turtle Myocardium

1956 ◽  
Vol 184 (3) ◽  
pp. 557-562 ◽  
Author(s):  
B. Katzung ◽  
A. Farah
Keyword(s):  
Low Temperatures ◽  
Energy Production ◽  
Contractile Force ◽  
The Other ◽  
Anaerobic Conditions ◽  
Stimulation Rate ◽  
Influence Of Temperature ◽  
Different Temperatures ◽  
Rapid Stimulation ◽  
Ionic Movements

The effects of changes in rate of stimulation on contractile force of turtle myocardium were studied at various temperatures. At 38°C an increase in rate produced an increase in the contractile force (positive treppe). At 14°C increasing the rate produced a decrease in the contractile force (negative treppe). At intermediate temperatures an increase in rate produced first a positive followed by a negative treppe. Under anaerobic conditions the results were qualitatively the same although contractility was reduced by 50–75%. The increase in contractile force seen after an episode of rapid stimulation (poststimulation contraction) was studied at different temperatures. An increase in the rapid stimulation rate produced an increase in poststimulation potentiation at all temperatures studied except at 14°C where an increase in rate produced a decrease in potentiation. Some of these results can be explained on the basis of energy production which is probably depressed at low temperatures. On the other hand some other factor related to rate of stimulation must influence contractile force. This factor may be related to the active state of A. V. Hill or may be related to ionic movements postulated by Hajdu and Szent-Gyorgyi.

scholarly journals Atomic specific heats between the boiling points of liquid nitrogen and hydrogen. I.—The mean atomic specific heats at 50° absolute of the elements a periodic function of the atomic weights

1913 ◽  
Vol 89 (609) ◽  
pp. 158-169 ◽  
Keyword(s):  
Periodic Function ◽  
Specific Heat ◽  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Liquid Hydrogen ◽  
Specific Heats ◽  
Boiling Points ◽  
Royal Institution ◽  
Series Of Experiments ◽  
The Mean

A method of determining the specific heat of substances at low temperatures was described in a paper on “Studies with the Liquid Hydrogen and Air Calorimeter,” also in the abstract of a lecture delivered at the Royal Institution entitled“ Liquid Hydrogen Calorimetry,” where the apparatus then used is illustrated. Continuing the use of the same method, but with some modification of the apparatus, the investigation has been extended to a large number of inorganic and organic bodies. In this later series of experiments, the measurements of the specific heats of materials by the liquid hydrogen calorimeter were made over a range of temperature from boiling nitrogen to boiling hydrogen, a fall of temperature of some 57° Abs.

scholarly journals In-Situ Isothermal Crystallization of Poly(l-lactide)

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3377
Author(s):  
Zirui Huang ◽  
Meiling Zhong ◽  
Haibo Yang ◽  
Enqin Xu ◽  
Dehui Ji ◽  
...  
Keyword(s):  
High Temperature ◽  
Nucleation Rate ◽  
Low Temperatures ◽  
Isothermal Crystallization ◽  
The Other ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures

The isothermal crystallization of poly(l-lactide) (PLLA) has been investigated by in-situ wide angle X-ray diffraction (WAXD) and polarized optical microscopes (POM) equipped with a hot-stage accessory. Results showed that the spherulites of PLLA were formed at high temperature, whereas irregular morphology was observed under a low temperature. This can be attributed to the varying rates of crystallization of PLLA at different temperatures. At low temperatures, the nucleation rate is fast and hence the chains diffuse very slow, resulting in the formation of imperfect crystals. On the other hand, at high temperatures, the nucleation rate is slow and the chains diffuse fast, leading to the formation of perfect crystals. The change in the value of the Avrami exponent with temperature further verifies the varying trend in the morphological feature of the crystals.

scholarly journals A Quick Note on Freeze-Fixing Tissue in Liquid Nitrogen

2001 ◽  
Vol 9 (2) ◽  
pp. 34-35
Author(s):  
Philip Oshel
Keyword(s):  
Liquid Nitrogen ◽  
Liquid Hydrocarbon ◽  
The Other ◽  
Liquid Oxygen ◽  
Explosion Hazard ◽  
Safe Place ◽  
Normal Liquid ◽  
Fire And Explosion ◽  
Ordinary Cooking

There are two possibilites for plunge freezing in LN2: one is “normal” liquid nitrogen -- as it comes from the dewar, the other is slush nitrogen.If using liquid nitrogen without slush, then something like isopentane, ethane, or propane (ordinary cooking propane will do) must be used. The caveat is that using these liquid gases is a serious fire and explosion hazard, especially since liquid oxygen forms at liquid nitrogen temperatures, and dissolves into the liquid hydrocarbon. These gases can be used safely (1 have done so) but they take care and understanding of what's happening, and a safe place to dispose of the cryogen.

III. On some of the products of the distillation of boghead coal at low temperatures

1857 ◽  
Vol 8 ◽  
pp. 119-120
Keyword(s):  
Nitro Compound ◽  
Alkaline Solution ◽  
Boiling Point ◽  
Low Temperatures ◽  
The Other ◽  
Low Density ◽  
Boiling Points ◽  
Careful Treatment ◽  
Pleasant Odour ◽  
Two Bodies

In presenting a brief preliminary notice of an investigation of the substances obtained by distilling boghead coal at low temperatures, I may observe that I was induced to undertake it from remarking the low density of the naphtha produced in the process; it being only .750 at 60° F., although its boiling-point, previous to the rectifications, was as high as 290° F. After fifteen complete fractionations of the portion distilling below 310° F., boiling-points were obtained as low as 170°, and it was found that the fluid could be separated, by careful treatment with fuming nitric, or a mixture of nitric and sulphuric acids, into two bodies, one forming a nitro-compound, the other being unacted on. The latter was washed several times with a strong alkaline solution, and, after being digested for a few days with sticks of potash to remove adherent moisture, rectified over sodium. In this manner I obtained a colourless and very mobile fluid with a pleasant odour, distantly resembling that of hawthorn blossoms. Its density at 60° was .725.

Foil Bearing Performance in a Liquid Nitrogen and Liquid Oxygen Turbopump

1994 ◽  
Author(s):  
GARY GENGE ◽  
MARSHALL SAVILLE ◽  
ALSON GU
Keyword(s):  
Liquid Nitrogen ◽  
Liquid Oxygen ◽  
Foil Bearing

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

scholarly journals A Comparative Electrochemical and Morphological Investigation on the Behavior of NiCr and CoCr Dental Alloys at Various Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Florentina Golgovici ◽  
Mariana Prodana ◽  
Florentina Gina Ionascu ◽  
Ioana Demetrescu
Keyword(s):  
Low Temperatures ◽  
Artificial Saliva ◽  
Electrochemical Stability ◽  
Morphological Investigation ◽  
Dental Alloys ◽  
Ion Release ◽  
Icp Ms ◽  
Different Temperatures ◽  
Good Concordance ◽  
Increasing Temperature

The purpose of our study is to compare the behavior of two reprocessed dental alloys (NiCr and CoCr) at different temperatures considering the idea that food and drinks in the oral cavity create various compositions at different pH levels; the novelty is the investigation of temperature effect on corrosion parameters and ion release of dental alloys. Electrochemical stability was studied together with morphology, elemental composition and ions release determination. The results obtained are in good concordance: electrochemistry studies reveal that the corrosion rate is increasing by increasing the temperature. From SEM coupled with EDS, the oxide film formed on the surface of the alloys is stable at low temperatures and a trend to break after 310K. ICP-MS results evidence that in accordance with increasing temperature, the quantities of ions released from the alloys immersed in artificial saliva also increase, though they still remain small, less than 20 ppm.

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