Changes In Specific Gravity Research Articles

Weight loss, specific gravity and mealiness during storage of Russet Burbank potatoes

Oregon-grown Russet Burbank late-crop potatoes from 16 randomly selected farms were divided into six specific gravity classes and stored at 40 F and 85% rh for 6 months. Specific gravity and weight changes were determined monthly on these tubers and organoleptic tests were made at the close of the storage period by an experienced judging panel. Matching sets of tubers in three specific gravity classes, 1.1095, 1.105 and 1.110, were judged for mealiness at harvest and after 1, 2, 4 and 6 months.

熱サイクルによる原子炉用金属材料の変形について

In order to clarify the basic characteristics on the thermal fatigue strength of metals, the authors have investigated on the changes in dimension, deformation, hardness, specific gravity, microstructure, temperature distribution and yield strength at elevated temperatures during simple thermal cycling of the various metals and alloys for reactor use, and the following results were obtained:(1) Armco iron and 304L stainless steel elongated in longitudinal direciton, but carbon steel having various carbon contents, 21/4Cr-1 Mo steel and four kinds of Fe-Al-Cr alloy contracted after the thermal cycling.(2) The grain growth due to thermal cycling of both 304L stainless steel and Fe-7.5 Al-6 Cr alloy containing 0.5% Ti and 1% Nb which suppressed the contraction was faily small. But in both alloys, surface crack occurred in the early stage of thermal cycling and propagated to the interior of samples. In the other Fe-Al-Cr alloys which displayed contraction by thermal cycling remarkable grain growth occurred and, in these cases, crack initiated only on the surface layer of sample at later stages than in 304L stainless steel, where that did not propagated. Therefore the grain growth itself could not be seemed as the essential cause of dimensional changes, because thermal stresses due to thermal cycling are relieved during the grain growth and not to promote but to retard the dimensional changes.(3) The temperature and yield strength distributions in sample during thermal cycling of 304L stainless steel and two kinds of Fe-Al-Cr alloy (8% Al and 12% Al) were measured. For latter alloys the intense decrease of the yield strength was observed at higher temperature than 500-550°C but for former alloy such marked change of yield strength was not observed through a temperature range up to 750°C. From these results, the authors concluded that the essential cause of the dimensional changes in such metals and alloys having simple phase as armco iron, 304L stainless steel and Fe-Al-Cr alloys depends generally upon the amount of thermal strain due to temperature gradient and the change in yield strength.Besides, the authors suggested that whether elongation or contraction was dependent apparently upon the existence of the marked decrease of yield strength within the cycling temperature range. However, the critical values could not be decided quantitatively because of lack in data. The authors will study further quantitatively to clarify the mechanism of the above mentioned phenomena.

Manifestations of injury in yeast cells exposed to subzero temperatures. II. Changes in specific gravity and in the concentration and quantity of cell solids.

Mazur, Peter (Oak Ridge National Laboratory, Oak Ridge, Tenn.). Manifestations of injury in yeast cells exposed to subzero temperatures. II. Changes in specific gravity and in the concentration and quantity of cell solids. J. Bacteriol. 82:673-684. 1961.-It has previously been established that subjecting cells of Saccharomyces cerevisiae to rapid cooling to -30 C results in cell death and in certain morphological alterations. The alterations consisted of the loss of the central vacuole and a 50% decrease in volume. The present experiments were concerned with determining whether the volume decrease was the result of the loss of water alone or of water plus cellular solutes. The density of the "frozenthawed" cells was found to increase from 1.14 to 1.25 g/cm(3) on the basis of measurements of the sedimentation rate of the cells. Interferometric and refractometric measurements indicated, furthermore, that the concentration of cell solids increased from 20 to 28%, whereas the total mass of cell solids decreased from 25 to 17 mumug/cell. The decrease in cell volume was thus shown to be the result of loss of solution from the cells, a solution containing 11 to 16% solids. Measurements of the rate of dialysis suggested that most or all of these solids had a molecular weight below 600. The findings are consistent with the view that low-temperature exposure destroyed the vacuolar membrane and sufficiently damaged the permeability barriers of the cell to permit escape of low molecular weight compounds. The damage was present a few seconds after thawing, and may, therefore, have been a direct result of intracellular ice crystals which, on the basis of previous studies, are believed to be responsible for death from low-temperature exposure.

Sensitive bioassay method for measuring antidiuretic hormone in mammalian plasma.

SummaryA method of bioassay for small amounts of antidiuretic hormone in plasma of a dog is presented. The method utilizes rats rendered unconscious with ethanol, under constant water load, and with intravenous injections of all standards and unknowns. Change in specific gravity of rat urine expressed as antidiuretic index is used as criterion of potency. This method appears to be the most sensitive bioassay for ADH available in that small dose changes of reference vasopressin, or endogenous circulating ADH, can be differentiated.

A STUDY ON THE AFTER-INVASION REACTION FROM THE BLOOD PROPERTIES IN THE TONSILLECTOMY

Observations were made of the changes of specific gravity in blood in the tonsillectomy, and the following results were obtained.1) After the injection of 0.5% Procain solution for the local anaesthesia, the specific gravity of whole blood (GB) and that of blood serum (Gs) were found to decrease in a similar process, although the decrease of (Gj) was less than that of (GB) in a slight extent.2) In order to detect a more detailed relation between the (GB) and the (Gs) reduction, an examination was made of the relative change between (GB-Gs) and (Gs- 1).The paradoxical phenomena was seen as a relationship between the two values during the period from the local injection to thirty minutes after the operation as well as at the point of two hours after the operation.3) From the above results it seems likely that the time inducing the shock reaction which has been clinically experienced after the tonsillectomy may be associated with the paradoxical phenomenon.

Blood and plasma specific gravity changes during acute alterations in hemodynamics in splenectomized dogs.

A variety of procedures were used to change hemodynamics acutely and thereby to produce changes in blood volume. Changes in plasma specific gravity showed no relation to those in aortic pressure or total peripheral resistance, but were related to central venous pressure. The simultaneous cell fraction tended to vary reciprocally with the plasma specific gravity, indicating a bulk transfer of either red cells or of plasma between the large blood vessels and peripheral beds.

Volume changes of tissues in physiological fluids during fixation in osmium tetroxide or formaldehyde and during subsequent treatment

The changes in volume, weight and specific gravity of tissue samples during fixation in osmium tetroxide or formaldehyde and subsequent infiltration with methacrylate or paraffin were studied in more than 600 tissue specimens. Substantial changes in volume and weight were found, and as a rule the weight changes closely parallelled the volume changes. The influence of the histological procedures on the specific gravity was not so pronounced. During fixation in 1 per cent osmium tetroxide in Tyrode's solution at pH 7.2, a rapid increase of volume took place. Half of the final value was reached after only 15 minutes and the swelling was practically complete after 4 hours. After 24 hours it amounted to 30 per cent. Fixation in formaldehyde likewise caused swelling, which was inversely proportional to the concentration (0.5–16 per cent). With 4 per cent formaldehyde in Krebs-Ringer solution the swelling amounted to 18 per cent after 12 hours, and half of this value was reached in about 30 minutes. Specimens left in the fixation fluids for long periods displayed secondary shrinkage at a rate apparently independent of the concentration of fixative. During dehydration in ethanol, marked shrinkage occurred that averaged 23 per cent for osmium-fixed and 33 per cent for formaldehyde-fixed material. Stepwise dehydration caused less abrupt volume changes, although the end-result differed but little. Among other dehydrating agents, miscible with methacrylate (methanol, acetone, 2-ethoxy-ethanol, dioxane, triethylphosphate), only methanol appeared to give better results than ethanol. Infiltration with methacrylate caused only slight shrinkage, around 7 per cent, regardless of the preceding fixative. During polymerization, however, methacrylate undergoes a 20 per cent reduction of its volume. As far as can be judged from planimetric observations, this shrinkage is to a great extent transferred to the specimens. Paraffin infiltration caused shrinkage of around 30 per cent. With osmium-fixed specimens the fixation temperature influenced the shrinkage during infiltration. Lower fixation temperature gave greater shrinkage. In other stages the temperature had little influence on volume changes. The swelling observed during fixation was found to be due, not to the fixing agents themselves, but to the aqueous media in which they were dissolved. When specimens were placed in saline, Tyrode's, Krebs-Ringer's and sucrose solutions, swelling took place in all of them, including the strongly hypertonic ones. The swelling was inversely proportional to the concentration and was less pronounced in sucrose than in the other medias. Addition of the fixatives, osmium tetroxide or formaldehyde, reduced the swelling to an extent that cannot be explained merely by osmotic action. The addition of macromolecules such as gelatin or dextran was found to reduce the swelling during fixation. The swelling phenomenon could be completely abolished if dextran and sucrose were added in suitable amounts to the osmium tetroxide solution. From the results obtained the following conclusions can be drawn. During conventional preparation procedures for histological specimens, major changes in volume, weight and specific gravity occur. Doubtless, these changes considerably affect the original geometry of the tissues constituents. It is possible, however, to reduce the volume alterations e.g. by addition of colloid-osmotically active substances.

Fluid density measurements by means of gamma ray absorption

The paper discusses the phenomena involved and the parameters controlling the usefulness of a method of measuring the specific gravity of liquids flowing in a pipe (during manufacturing processes), and of detecting the interface between liquids having different specific gravities, e.g. petroleum products. To ensure stability and accuracy a pressurized ionization chamber is used in conjunction with a vibrating reed electrometer, and a heavily shielded gamma source of the order of one curie. Changes in specific gravity of 0.2% of liquids in steel walled pipes of up to 14 inches diameter have been detected. Details are given of typical industrial installations.

ACCLIMATION TIMES IN DAHLBOMINUS FUSCIPENNIS (ZETT.) (HYMENOPTERA: CHALCIDOIDEA)

Thermal adjustment to high temperatures in Dahlbominus fuscipennis (Zett.) is a rapid process. The peaks of resistance to the lethal temperature of 43 °C. for starved adults held at 36 °C. and 32 °C. were reached in two and three hours respectively. It is suggested that the fall in resistance after these peaks was caused by changes in specific gravity of the haemolymph.

The oxygen consumption of Artemia salina (L.) in different salinities

1. The oxygen consumption of female Artemia was measured with animals reared in sea water (S‰ 35) and in brine of salinity 140‰. The animals ranged in length from 3.4 to 7.6 mm. 2. It was necessary to know whether surface area or body weight was the best standard for comparing oxygen consumption in different salinities. Changes in specific gravity and body shape with increasing size and in brines of different salinity were, therefore, measured. 3. The specific gravity of females does not change significantly over the size range investigated nor with the salinity in which the animals are reared. 4. In sea water and brine of salinity 140‰ the abdomen becomes relatively longer as the total length of the animal increases. In the more concentrated brine the abdomen is relatively longer and narrower than in animals reared in sea water. 5. The oxygen uptake of females is of the same magnitude in animals reared in sea water and in brine of salinity 140‰, expressed per individual per hour in relation to the average dry weight. Total oxygen consumption is proportional to the 0.662 power of the dry weight.

Studies on Indian Talcs

The structure of talc, its properties and effect of heat on its various properties have been discussed in the form of survey of literature. Three different samples of talc from different localities viz. Udaipur, Jaipur and Rupaund were taken and their various properties have been studied. The properties investigated include chemical analysis, differential thermal analysis, petrological studies and particle size distribution of powdered talc samples. The effect of heat on these samples of talcs with regard to specific gravity changes, shrinkage, linear thermal expansion, weight loss behaviour and other structural changes have been determined.

Changes in specific gravity of the growing crystalline lens; a technique for investigation of pathogenesis of cataract.

A CATARACT may be defined as a loss of transparency of the crystalline lens, or an opacification occurring at any place in the lens or its capsule. 1 The mechanism for this opacification has been the subject of extensive research. Since the lens is a living, cellular organ, we may expect that changes in its protein structure are primarily involved in any alteration of its optical behavior. The optical properties of protein systems in general have excited only minor interest, as such data are of vital concern only in the cornea, lens, and vitreous body of the eye. It has been shown, however, that physical and chemical alterations of such proteins as muscle myosin, gelatin, and fibrin produce marked alterations in such optical properties as polarization of light, transparency, and absorption in various portions of the energy spectrum. 2 It has been shown that the cornea owes its transparency to

Cardiovascular responses to rattlesnake venom.

ArticleCardiovascular Responses to Rattlesnake VenomA. C. Witham, J. W. Remington, and E. A. LombardA. C. WithamFrom the Department of Physiology, Medical College of Georgia, Augusta, Georgia, J. W. RemingtonFrom the Department of Physiology, Medical College of Georgia, Augusta, Georgia, and E. A. LombardFrom the Department of Physiology, Medical College of Georgia, Augusta, GeorgiaPublished Online:01 Jun 1953https://doi.org/10.1152/ajplegacy.1953.173.3.535MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByCrotalus Horridus Venom15 October 2004North American pit vipersJournal of Wilderness Medicine, Vol. 3, No. 4Characteristics of the action of Crotalus horridus horridus (timber rattlesnake) venom on the isolated, perfused rat heartToxicon, Vol. 25, No. 12Cardiovascular Effects of Snake VenomsCardiovascular failure produced by a peptide from the venom of the Southern Pacific rattlesnake, Crotalus viridis helleriToxicon, Vol. 17, No. 5ACUTE HEMODYNAMIC EFFECTS OF RATTLESNAKE, CROTALUS VIRIDIS HELLERI, VENOMTHE RELEASE OF CHEMICAL SUBSTANCES FROM THE PULMONARY AND BRONCHIAL CIRCULATIONBlood and Plasma Specific Gravity Changes During Acute Alterations in Hemodynamics in Splenectomized DogsCirculation Research, Vol. 6, No. 2 More from this issue > Volume 173Issue 3June 1953Pages 535-541 Copyright & PermissionsCopyright © 1953 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1953.173.3.535PubMed13065483History Received 15 February 1953 Published online 1 June 1953 Published in print 1 June 1953 Metrics

マグネシウムを主とするマグネシウム-アルミニウム合金の時効について

To study the mechanism of age-hardening of magnesium rich aluminium-alloys, the following experiments were performed. Aluminium-magnesium alloy containing 10.65% Al (by wt.) was solution-treated at 420° for 50 hrs, then quenched in cold water. With these specimens, (1) changes in hardness, electrical resistance, and microscopic structures during aging at 100°, 125°, 150°, 175°, 200° and 250° were studied and also (2) changes in hardness, electrical resistance, specific gravity, thermal expansion and microscopic structures during heating from room temperature to 300° at the heating velocity of 1°C per min, were measured. The results are as follows: (1) The age-hardening of this alloy depends, principally, on strains caused by precipitation of δ-phase (intermetallic compound Al3Mg4) from super-saturated solid solution. Compared with those of magnesium rich zinc alloys, their strains are more remarkable and removal of them is more difficult. A slight hardening prior to precipitation is recognized. (2) According to changes in microscopic structures, precipitation takes place, at first, in the vicinity to grain boundaries and, after this stage has finished, begins at the remaining parts of the grains. This discontinuity decreases as the aging temperature becomes higher, and, at last, disappears. By overheating considerable softening is caused at the central part of grains, but, the softening is less apparent at parts adjacent to grain boundaries. The precipitation of this alloy belongs to the “discontinuous type”. The longer the aging-time, and the higher the aging temperature the coarser becomes the precipitate, that is, the sorbitic structure changes to the pearlitic structure.

Positive‐Plate Self‐Discharge in the Lead‐Acid Cell

Specific gravity changes on stand in lead‐acid cells having 12 per cent antimonial grids were followed for 46 months. Self‐discharge at the positive plate was found to occur at rates comparable to negative‐plate self‐discharge. It appears to proceed primarily through oxidation of the antimony in the grid by the in the plate. Hydrogen gas was found to reduce in sulfuric acid.

Variations in specific gravity of potatoes

Over 20,000 tubers of 6 varieties of potatoes obtained from 10 different states were graded individually for specific gravity. Varietal differences were noted in the specific gravity values. Katahdin showed the greatest variability and Irish Cobbler and Chippewa the least. The variability in specific gravity as shown by the standard deviations indicates that some lots and varieties are more adaptable than others to commercial separation into different specific gravity lots. The moisture content of the air in the storage rooms is an important factor controlling changes in specific gravity during storage. Potatoes stored at relative humidities of approximately 90 per cent showed slight changes in specific gravity during storage but lower humidities caused noticeable changes. Varieties differed materially in shrinkage and in their changes in specific gravity during storage.

Changes in specific gravity, starch content, and sloughing of potatoes during storage

Changes in specific gravity, starch content, and sloughing of potatoes during storage

Effect of Surface Condition of a Sphere on Its Water-Entry Cavity

An investigation of factors which influence the formation of a cavity when a sphere enters water vertically is described. It was found that cavities are formed at much lower entry speeds for contaminated spheres than for clean ones, but that there is little dependence on the type of the contaminant. In regard to the scaling of this effect, the tendency to form a cavity varies little with change of size or specific gravity of the sphere. Water-entry cavities are observed to form at velocities much lower than those required for incipient cavitation in the water tunnel; consequently, a relation between the two effects appears improbable. Some dependence of cavity formation on viscosity might be inferred from the observation that cavities were formed at lower entry speeds by spheres coated with liquids of high viscosity than by spheres without this coating.

On the Changes of Specific Gravity of the Blood of Silkworms in the Course of Development

On the Changes of Specific Gravity of the Blood of Silkworms in the Course of Development

鋼に対する合金元素としての窒素（第6報）鋼の青熱脆性に及ぼす酸素及び珪素の影響

The present investigation has been carried out to explain the mechanism of blue-brittleness in steels. In the 3rd∼6th reports under this title, it has been shown that the blue-brittleness would not occur in steels free from the nitrogen and that the more the nitrogen content in steels is the more clearly the blue brittleness appears.In present investigation the follwoing experiments were carried out.(A) The effect of the annealing in nitrogen or in hydrogen atmosphere was determined by the tensile test at 0∼350° on the specimens shown in Table 1 and the results of these were plotted in Fig. 1∼5.(B) The effect of cold work on the blue-brittleness was examined on the specimens shown in Table 2, that is tempered for 1 hour at 180° after cold work at room temperature ; the tensile values of these are plotted in Fig. 6∼8.(C) The effect of different testing speed was determined on the specimens shown in Table 3 and the tensile values of these are plotted in Fig. 9,10.(D) The change of specific gravity on the specimens tempered for 1 hour at 0∼350° after cold work at room temperature was measured as shown in Table 4.(E) The figure of stress by Fry’s method were examined on the specimens that had used for the tensile test at each testing temperature. From those experiments the following results were obtained.(F) In accordance with either the increase or decrease of nitrogen content in steels by heating it in nitrogen or in hydrogen atmosphere, the degree of blue brittleness varied.(G) The blue-brittleness decreased on the specimens in which some parts of nitrogen had been precipitated by cold working and tempering.(H) The temperature range of blue brittleness moved to a higher temperature range with the increase of testing speed.(I) There is a clear correlation between the blue brittleness and Fry’s figure of stress.From the present and former investigations authors concluded the mechanism of blue brittleness as follow :The blue brittleness in steel is due to the precipitation of nitride or carbide from α-iron by the existence of working stress : and the brittleness by nitrogen appears much more exactly in lower temperature range than that by carbon.