scholarly journals THE SWELLING AND OSMOTIC PRESSURE OF GELATIN IN SALT SOLUTIONS

1926 ◽  
Vol 8 (4) ◽  
pp. 317-337 ◽  
Author(s):  
John H. Northrop ◽  
M. Kunitz
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Salt Solution ◽  
Modulus Of Elasticity ◽  
Elastic Limit ◽  
Ion Concentration ◽  
Salt Solutions ◽  
Original Volume ◽  
Expected Result ◽  
Do So

1. The swelling and the osmotic pressure of gelatin at pH 4.7 have been measured in the presence of a number of salts. 2. The effect of the salts on the swelling is closely paralleled by the effect on the osmotic pressure, and the bulk modulus of the gelatin particles calculated from these figures is constant up to an increase in volume of about 800 per cent. As soon as any of the salts increase the swelling beyond this point, the bulk. modulus decreases. This is interpreted as showing that the elastic limit has been exceeded. 3. Gelatin swollen in acid returns to its original volume after removal of the acid, while gelatin swollen in salt solution does not do so. This is the expected result if, as stated above, the elastic limit had been exceeded in the salt solution. 4. The modulus of elasticity of gelatin swollen in salt solutions varies in the same way as the bulk modulus calculated from the osmotic pressure and the swelling. 5. The increase in osmotic pressure caused by the salt is reversible on removal of the salt. 6. The observed osmotic pressure is much greater than the osmotic pressure calculated from the Donnan equilibrium except in the case of AlCl3, where the calculated and observed pressures agree quite closely. 7. The increase in swelling in salt solutions is due to an increase in osmotic pressure. This increase is probably due to a change in the osmotic pressure of the gelatin itself rather than to a difference in ion concentration.

The Theoretical Volumetric Displacement of a Check-Valve Type, Digital Displacement Pump

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Noah Manring ◽  
Christopher Williamson
Keyword(s):  
Bulk Modulus ◽  
Flow Rate ◽  
Modulus Of Elasticity ◽  
Check Valve ◽  
Volumetric Flow Rate ◽  
Theoretical Explanation ◽  
Residual Volume ◽  
Displacement Pump ◽  
Opening And Closing ◽  
Piston Chamber

This paper has been written to develop closed-form equations for describing the theoretical displacement of a check-valve type, digital displacement pump. In theory, the digital displacement pump is used to alter the apparent volumetric displacement of the machine by short circuiting the flow path for reciprocating pistons within the machine that would ordinarily deliver a full volumetric flow rate to the discharge side of the pump. The short circuiting for the pistons is achieved by opening and closing a digital valve connected to each piston chamber at a desired time during the kinematic cycle for each reciprocating piston. Experience with these machines has shown that the expected volumetric displacement for the machine tends to decrease with pressure. This paper presents a theoretical explanation for the reduced volumetric displacement of the pump and quantifies the expected behavior based upon the digital valve command, the residual volume of fluid within a single piston chamber, and the fluid bulk modulus-of-elasticity. In summary, it shown that the apparent volumetric displacement of the machine may be reduced by as much as 10% for high-displacement commands and by as much as 30% for low-displacement commands.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

scholarly journals Charge regulating macro-ions in salt solutions: screening properties and electrostatic interactions

Soft Matter ◽  
2018 ◽  
Vol 14 (29) ◽  
pp. 6058-6069 ◽  
Author(s):  
Yael Avni ◽  
Tomer Markovich ◽  
Rudolf Podgornik ◽  
David Andelman
Keyword(s):  
Salt Solution ◽  
Electrostatic Interactions ◽  
Regulation Mechanism ◽  
Salt Solutions ◽  
Charge Regulation

We revisit the charge-regulation mechanism of macro-ions and apply it to mobile macro-ions in a bathing salt solution.

The effect of wilting on butyric acid fermentation in silage.

1958 ◽  
Vol 6 (3) ◽  
pp. 204-210 ◽  
Author(s):  
G.W. Wieringa
Keyword(s):  
Lactic Acid ◽  
Osmotic Pressure ◽  
Butyric Acid ◽  
Ion Concentration ◽  
Acid Fermentation ◽  
Silage Fermentation ◽  
Lactic Acid Content ◽  
Vitro Development ◽  
Butyric Acid Fermentation

A comparatively slight increase in environmental osmotic pressure inhibited the in vitro development of butyric-acid bacteria [Clostridium spp.], especially with increasing H-ion concentration. Sub-lethal concentrations of salt (NaCl, KCl, Na2SO4) and/or H-ions retarded the start of clostridial development and reduced the quantity of butyric acid produced. In wilted grass silage it was shown that osmotic pressure plays a considerable part in repressing butyric-acid fermentation in the initial stages of silage fermentation. Low temperature (< 20-25 degrees C.), low pH (< 4.2), high lactic-acid content and high osmotic pressure were more harmful to clostridia than to lactic-acid bacteria.-R.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Research on Measurement Method for Polymer Melt Bulk Modulus of Elasticity

2011 ◽  
Vol 16 ◽  
pp. 72-78
Author(s):  
XU Hong ◽  
WU Daming ◽  
LIU Ying ◽  
ZHANG Yajun
Keyword(s):  
Bulk Modulus ◽  
Modulus Of Elasticity ◽  
Measurement Method ◽  
Polymer Melt

Effects of Deicing Salt Solutions on Physical Properties of Pavement Concretes

2012 ◽  
Vol 2290 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Jitendra Jain ◽  
Jan Olek ◽  
Anna Janusz ◽  
Daria Jozwiak-Niedzwiedzka
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Physical And Mechanical Properties ◽  
Exposure Period ◽  
Relative Effect ◽  
Pulse Velocity ◽  
Ion Concentration ◽  
Portland Cement Concrete ◽  
Salt Solutions ◽  
Safe Driving

Salt solutions are used on pavement surfaces during wintry weather events to ensure safe driving conditions. In addition to sodium chloride (NaCl), which continues to be traditionally used as a deicer, solutions of calcium chloride (CaCl2) and magnesium chloride (MgCl2) are being increasingly used to provide a more consistent ice and snow control and thus ensure safe driving. This paper assesses the effects of three salt solutions (NaCl, CaCl2, and MgCl2) on several physical and mechanical properties of pavement concretes. These deicing solutions were used under simulated wetting–drying (W-D) and freezing–thawing (F-T) exposure regimes with total ion concentration of the deicers of 10.5 molal for W-D exposure and 5.5 molal for F-T exposure. Two types of concretes were used in the study: ordinary portland cement concrete and fly ash concrete, in which 20% (by mass) of cement was replaced by Class C fly ash. The physical changes of cylindrical specimens subjected to the W-D regime were monitored by ultrasonic pulse velocity measurements after every 2 weeks of exposure until the end of the test. At the end of the W-D exposure period, the same test cylinders were used to obtain the compressive strength of the concrete. The results of all measurements, combined with visual observations of the overall condition of the specimen, were used to assess the relative effect of deicers (and the exposure conditions) on both types of concretes. The overall findings from this research indicated that exposure to the CaCl2 deicer resulted, in general, in more severe changes in the physical and mechanical properties of both types of concrete used in this study.

scholarly journals THE SWELLING OF ISOELECTRIC GELATIN IN WATER

1927 ◽  
Vol 10 (6) ◽  
pp. 893-904 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Elastic Strain ◽  
Elastic Force ◽  
Soluble Substance ◽  
Insoluble Material ◽  
Soluble Material ◽  
Initial Process

The swelling of isoelectric gelatin in water has been found to be in agreement with the following assumptions. Gelatin consists of a network of insoluble material containing a solution of a more soluble substance. Water therefore enters owing to the osmotic pressure of the soluble material and thereby puts the network under elastic strain. The process continues until the elastic force is equal to the osmotic pressure. If the temperature is raised or the blocks of gelatin remain swollen over a period of time, the network loses its elasticity and more water enters. In large blocks this secondary swelling overlaps the initial process and so no maximum can be observed. The swelling of small blocks or films of isoelectric gelatin containing from .14 to .4 gm. of dry gelatin per gm. of water is defined by the equation See PDF for Equation in which Ke = the bulk modulus See PDF for Equation. Ve = gm. water per gm. gelatin at equilibrium; Vf = gm. water per gm. gelatin when the gelatin solidified.

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