scholarly journals The effect of low temperature on hens' eggs

1925 ◽  
Vol 98 (691) ◽  
pp. 436-456 ◽  
Keyword(s):  
Low Temperature ◽  
Silicic Acid ◽  
Critical Length ◽  
Limited Range ◽  
Peculiar Feature ◽  
Freezing And Thawing ◽  
Original State ◽  
Critical Range ◽  
Time Changes

Colloids when frozen do not as a rule recover their original state on thawing. Stiles quotes many such cases, a well-known example being a gel of silicic acid which is separated by freezing and thawing into a mixture of water and solid flakes of acid. Similarly, when a solution of chlorophyll in water is frozen slowly, the chlorophyll on thawing is found to be aggregated into large flocks which slowly settle to the bottom. Recovery of state, however, takes place in certain systems, not necessarily the simplest, if the rate of freezing be high enough. The solution of chlorophyll furnishes an example. If it be frozen in liquid air it completely recovers its original state on thawing. Obviously the end temperature does not matter because it may be said with certainty that the frozen mass could be kept at the temperature of liquid air indefinitely without losing the capacity of reforming a solution on thawing. There must therefore exist a certain limited range of temperature within which alone the process of desolution can occur. Let us call this the critical range. The peculiar feature of any temperature within the critical range θ 1 - θ 2 is that, if the system be kept at that temperature for a critical length T of time, changes take place which are not reversed on thawing.

scholarly journals Morphological manifestations of freezing and thawing injury in bacteriophage T4Bo

1976 ◽  
Vol 77 (1) ◽  
pp. 119-127 ◽  
Author(s):  
P. R. M. Steele
Keyword(s):  
Low Temperature ◽  
Morphological Changes ◽  
Plaque Assay ◽  
Electron Microscopic Observation ◽  
Eutectic Phase ◽  
Phase Changes ◽  
Extended Form ◽  
Freezing And Thawing ◽  
Electron Microscopic ◽  
Tail Sheath

SUMMARYElectron microscopic observation of negatively stained preparations of frozen and thawed suspensions of T4Bo phage clearly separated the morphological changes produced by low-temperature salt denaturation from those produced by eutectic phase changes. Salt denaturation caused contraction of tail sheaths. Eutectic phase changes appeared to cause two separate lesions. Firstly the tail sheath was disjointed 18–22 nm. below the collar and the tail core was disjointed at 40–60 nm. below the collar, giving rise to separated heads with a small tail remnant, and separated tails in which the sheath remarkably remained in its extended form. Secondly, tears were seen in the head membranes of particles with collapsed empty heads. In all the experiments the percentage of normal phage particles counted electron-microscopically was close to the percentage of viable phage as determined by plaque assay.

scholarly journals XIV. On the properties of silicic acid and other analogous colloidal substances

1864 ◽  
Vol 13 ◽  
pp. 335-341 ◽  
Keyword(s):  
Low Temperature ◽  
Silicic Acid ◽  
Slow Rate ◽  
Cold Water ◽  
Water Solution ◽  
Frequent Occurrence ◽  
Quartz Crystals ◽  
Liquid Body ◽  
Ordinary Temperature

The prevalent notions respecting solubility have been derived chiefly from observations on crystalline salts, and are very imperfectly applicable to the ss of colloidal substances. Hydrated silicic acid, for instance, when in a soluble condition, is property, speaking a liquid body, like alcohol, scible with water in all proportions. We have no degrees of solubility speak of with respect to silicic acid, like the gelatinous condition, which is usually looked upon as destitute of solubility. The jelly of silicic acid may be more or less rich in combined water, as it is first pre-red, and it appears to be soluble in proportion to the extent of its hydragon. A jelly containing 1 per cent. of silicic acid, gives with cold water solution containing about 1 of silicic acid in 5000 water; a jelly con-ining 5 per cent. of silicic acid, gives a solution containing about 1 per acid in 10,000 water. A less hydrated jelly than the last mentioned still less soluble; and finally, when the jelly is rendered anhydrous, it ves gummy-looking white masses, which appear to be absolutely insoble, like the light dusty silicic acid obtained by drying a jelly charged with salts, in the ordinary analysis of a silicate. The liquidity of silicic acid is only affected by a change, which is permanent (namely, coagulation or pectization), by which the acid is converted into the gelatinous or pectous form, and loses its miscibility with water. The liquidity is permanent in proportion to the degree of dilution of silicic the contrary, by concentration, and by elevation of temperature. A liquid silicic acid of 10 or 12 per cent. pectizes spontaneously in a few hours at the ordinary temperature, and immediately when heated. A liquid of 5 per cent. may be preserved for five or six days; a liquid of 2 per sent. for two or three months; and a liquid of 1 per cent. or less are no doubt practically unalterable by time, and hence the possibility of soluble silicici acid existing in nature. I may add, however, that no solution, weak or strong, of silicic acid in water has shown any disposition to deposit crystals , but always appears on drying as a colloidal glassy hyalite. The formation of quartz crystals at a low temperature, of so frequent occurrence in nature, remains still a mystery. I can imagine that such crystals are formed at an inconceivably slow rate, and from solutions of silicic acid which are extremely dilute. Dilution no doubt weakens the colloidal character of substances, and may therefore allow their crystallizing tendency to gain ground and develope itself, particularly where the crystal once formed is completely insoluble, as with quartz.

Kinetics of Low Temperature Nitriding of Precipitation Hardened Stainless Steel

2011 ◽  
Vol 312-315 ◽  
pp. 530-535 ◽  
Author(s):  
Paweł Kochmański ◽  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Chemical Elements ◽  
Nitrided Layer ◽  
Nitriding Time ◽  
Diffusion Layers ◽  
Optical Spectrometry ◽  
Xrd Phase Analysis ◽  
Time Changes ◽  
Kinetics Of

The paper presents results of research on nitrided layers on precipitation hardened stainless steel, known also as 1RK91 (Sandvik NanoflexTM). Samples were subjected to low temperature nitriding. The influence of nitriding parameters on nitriding kinetics was investigated. The nitriding process was carried out in a mixture of NH3 50% and products of its dissociation as well as in 100% ammonia atmosphere at temperature range 425-475°C. To investigate the kinetics of nitrided layer formation, the nitriding time changes between 2 and 8 h. The obtained diffusion layers were examined using the following methods: light and scanning electron microscopy, XRD phase analysis. The distribution profiles of selected chemical elements were acquired using optical spectrometry GDOES.

Global Contour Saliency and Local Colinear Interactions

2002 ◽  
Vol 88 (5) ◽  
pp. 2846-2856 ◽  
Author(s):  
Wu Li ◽  
Charles D. Gilbert
Keyword(s):  
Limited Range ◽  
Average Density ◽  
Contour Integration ◽  
Contour Detection ◽  
Intermediate Step ◽  
Line Segments ◽  
Critical Range ◽  
Horizontal Connections ◽  
Line Elements ◽  
Contextual Interactions

Our visual system can link components of contours and segregate contours from complex backgrounds based on geometric grouping rules. This is an important intermediate step in object recognition. The substrate for contour integration may be based on contextual interactions and intrinsic horizontal connections seen in primary visual cortex (V1). We examined the perceptual rules governing contour saliency to determine whether the spatial extents of contextual interactions and horizontal connections match those mediating saliency. To quantify these rules, we used stimuli composed of randomly oriented nonoverlapping line segments. Salient contours within this complex background were formed by colinear alignment of nearby segments. Contour detectability was measured using a 2-interval-forced-choice design. Contour detectability deteriorated with increasing spacing between contour elements and improved as the number of colinear line elements was increased. At short contour spacing, the detectability reached a plateau with alignment of a few line segments that together formed a contour subtending several visual degrees. At intermediate spacing, saliency built up progressively with a greater number of colinear lines, extending up to 30°. When contour spacing was beyond a critical range (about 2°), however, the detectability dropped to chance levels, regardless of the number of colinear lines. Contour detectability was found to be a function not only of the relative spacing of contour elements with respect to the noise elements but also of the average density of the overall pattern. Furthermore, training significantly improved contour detection, increasing the critical spacing of line elements beyond which contours were no longer detectable. Our data suggest that global contour integration is based on mechanisms of limited spatial extent, comparable to the interactions observed in V1. These interactions can cascade over larger distances provided the spacing of stimulus elements is kept within a limited range.

Low Temperature Studies with Colloidal Silicic Acid

Science ◽  
1949 ◽  
Vol 110 (2850) ◽  
pp. 161-162 ◽  
Author(s):  
F. Hazel ◽  
J. A. Parker ◽  
E. Schipper
Keyword(s):  
Low Temperature ◽  
Silicic Acid

scholarly journals Effects of Lactobacillus plantarum on the Fermentation Profile and Microbiological Composition of Wheat Fermented Silage Under the Freezing and Thawing Low Temperatures

2021 ◽  
Vol 12 ◽  
Author(s):  
Miao Zhang ◽  
Lei Wang ◽  
Guofang Wu ◽  
Xing Wang ◽  
Haoxin Lv ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Low Temperature ◽  
Low Temperatures ◽  
Fungal Pathogens ◽  
Animal Feed ◽  
Ammonia Nitrogen ◽  
Poor Quality ◽  
Freezing And Thawing ◽  
Silage Fermentation ◽  
Repeated Freezing

The corruption and/or poor quality of silages caused by low temperature and freeze-thaw conditions makes it imperative to identify effective starters and low temperature silage fermentation technology that can assist the animal feed industry and improve livestock productivity. The effect of L. plantarum QZ227 on the wheat silage quality was evaluated under conditions at constant low temperatures followed by repeated freezing and thawing at low temperatures. QZ227 became the predominant strain in 10 days and underwent a more intensive lactic acid bacteria fermentation than CK. QZ227 accumulated more lactic acid, but lower pH and ammonia nitrogen in the fermentation. During the repeated freezing and thawing process, the accumulated lactic acid in the silage fermented by QZ227 remained relatively stable. Relative to CK, QZ227 reduced the abundance of fungal pathogens in silage at a constant 5°C, including Aspergillus, Sporidiobolaceae, Hypocreaceae, Pleosporales, Cutaneotrichosporon, Alternaria, and Cystobasidiomycetes. Under varying low temperature conditions from days 40 to days 60, QZ227 reduced the pathogenic abundance of fungi such as Pichia, Aspergillus, Agaricales, and Plectosphaerella. QZ227 also reduced the pathogenic abundance of Mucoromycota after the silage had been exposed to oxygen. In conclusion, QZ227 can be used as a silage additive in the fermentation process at both constant and variable low temperatures to ensure fast and vigorous fermentation because it promotes the rapid accumulation of lactic acid, and reduces pH values and aerobic corruption compared to the CK.

The kinetics and mechanisms of simulated British Magnox waste glass dissolution as a function of pH, silicic acid activity and time in low temperature aqueous systems

2000 ◽  
Vol 15 (9) ◽  
pp. 1399-1416 ◽  
Author(s):  
P.K. Abraitis ◽  
F.R. Livens ◽  
J.E. Monteith ◽  
J.S. Small ◽  
D.P. Trivedi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Silicic Acid ◽  
Waste Glass ◽  
Aqueous Systems ◽  
Glass Dissolution

Freeze-Thaw Cycle under the Conditions of Creep Tests of Plastics Geogrid

2012 ◽  
Vol 170-173 ◽  
pp. 317-321
Author(s):  
En Liang Wang ◽  
Bin Zhang ◽  
Jun De Chang
Keyword(s):  
Low Temperature ◽  
Impact Factor ◽  
Freezing And Thawing ◽  
Creep Tests ◽  
Thawing Cycle ◽  
Thaw Cycle ◽  
Creep Characteristics ◽  
Freeze Thaw Cycle ◽  
Different Temperatures ◽  
The One

Through testing the creep characteristics of plastic geogrid under the temperature of 20°C，10°C，0°C and -20°C, we obtained the creep characteristics curve under the different temperature.In order to obtioning the creep regulations of plastic geogrid by freezing and thawing cycle , we made the plastic geogrid for10 times freezing and thawing cycle at -20°C - 20°C, the one which was tested under the temperature of 20°C until its deformation became stable. Conclusions: (1) The creep of the plastic geogrid under different temperatures is quite different, it is greatly influenced by temperature and the lower the temperature the smaller the creep value; freezing and thawing cycle have influence in creep characteristics,In the condition of freezing and thawing cycle,while the creep value get stable at the normal temperature, the creep value also increasing with the temperature getting high and decreasing with temperature getting low; (2) According to the creep regulations under low temperature and freezing and thawing cycle condition,we advance the counting method of impact factor of freezing and thawing cycle, DR and creep impact factor of low temperature FcR.

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