Some Observations on the Relationship Between Lubricant Mechanical and Dielectric Transitions Under Pressure

1980 ◽  
Vol 102 (2) ◽  
pp. 229-234 ◽  
Author(s):  
S. Bair ◽  
W. O. Winer
Keyword(s):  
Atmospheric Pressure ◽  
Frequency Range ◽  
Two Fluids ◽  
Constant Rate ◽  
Constant Viscosity ◽  
The Relationship ◽  
Dielectric Transition

Viscoelastic transition measurements of several lubricants by volume dilatometry to pressures of 1.75 GPa, dielectric transitions at atmospheric pressure on five fluids in a frequency range of 0.2 to 500 kHz and on two fluids in the same frequency range to pressures of 0.55 GPa are reported. Lines of constant rate dilatometry transition, constant rate dielectric transition and constant viscosity are shown to be essentially parallel on a temperature-pressure diagram.

The relationship between group velocity and phase velocity for finite, discrete observations

1977 ◽  
Vol 67 (5) ◽  
pp. 1249-1258
Author(s):  
Douglas C. Nyman ◽  
Harsh K. Gupta ◽  
Mark Landisman
Keyword(s):  
Phase Velocity ◽  
Group Velocity ◽  
The Other ◽  
Frequency Range ◽  
Finite Frequency ◽  
Discrete Observations ◽  
Practical Situation ◽  
Order Polynomial ◽  
Observational Errors ◽  
The Relationship

abstract The well-known relationship between group velocity and phase velocity, 1/u = d/dω (ω/c), is adapted to the practical situation of discrete observations over a finite frequency range. The transformation of one quantity into the other is achieved in two steps: a low-order polynomial accounts for the dominant trends; the derivative/integral of the residual is evaluated by Fourier analysis. For observations of both group velocity and phase velocity, the requirement that they be mutually consistent can reduce observational errors. The method is also applicable to observations of eigenfrequency and group velocity as functions of normal-mode angular order.

Anaerobic heat production of bull spermatozoa II. The effects of changes in the colligative and other properties of the suspending medium

1959 ◽  
Vol 151 (942) ◽  
pp. 1-22 ◽  
Keyword(s):  
Heat Production ◽  
Environmental Conditions ◽  
Atmospheric Pressure ◽  
Hypotonic Medium ◽  
Depressant Effect ◽  
Depressant Action ◽  
The Difference ◽  
Isothermal Calorimeter ◽  
Future 2 ◽  
The Relationship

1. The anaerobic heat production of bull spermatozoa has been examined under varying environmental conditions, in an isothermal calorimeter, capacity 2·4 ml., working at atmospheric pressure. The minimum detectable heat production was 10 μ cal/min. The calorimeter was calibrated with needles containing plutonium oxide of known heat production, both now and in the future. 2. Abnormal environmental conditions or treatments, such as washing, hypertonicity, hypotonicity and dilution elicited a shock reaction characterized by depressed metabolism, followed by a gradual recovery or adaptation, which in certain conditions was complete. 3. The effect of the pH of the suspending medium was examined under rigorous conditions. A low pH causes a reduction in metabolism but the response is not linear, there being a change in the relationship between heat production and pH within the range pH 6·9 to 6·4. The difference between the rate of heat production at pH 7·4 and 6·9 is insignificant, but at pH 6·4, heat production is reduced to nearly half its normal value. 4. The rate of heat production of bull spermatozoa in hypertonic and hypotonic media has been examined. The osmotic pressure range was from 3·4 to 15·1 atm, Δ = –0·28 to –1·25, or, in terms of mM-NaCl, 80 to 368. Hypertonic media in which Δ = –0·75, 0·22 below the normal tonicity, have a barely perceptible effect; but a hypotonic medium in which Δ = –0·42, 0·11 above the normal tonicity, has a depressant action, though adaptation occurs. 5. The depressant effect of hypertonicity and hypotonicity is less marked, relative to controls, at pH 6·4 than at 7·4. 6. The rate of anaerobic heat production declines before substrate exhaustion or a reduction in the pH of the medium are likely to have any effect on sperm metabolism. The following possible explanations are examined: (i) that the energy required for high sperm activity is of the same order as the rate of free energy change associated with anaerobic fructolysis; (ii) that the rate of A . T . P . synthesis during anaerobic fructolysis does not keep pace with the rate of A . T . P . hydrolysis necessary to provide the energy for high sperm activity.

Role of cardiac lymph and interstitial fluid in lipid metabolism of canine heart

1978 ◽  
Vol 56 (6) ◽  
pp. 1041-1046 ◽  
Author(s):  
Pierre Julien ◽  
Gilles R. Dagenais ◽  
Laimonis Gailis ◽  
Paul-E. Roy
Keyword(s):  
Fatty Acids ◽  
Femoral Vein ◽  
Canine Heart ◽  
Triglyceride Fraction ◽  
Constant Rate ◽  
Arterial Concentration ◽  
Anesthetized Dogs ◽  
Arterial Plasma ◽  
The Relationship

To determine whether cardiac interstitial spaces participate in cardiac fatty acid pool, the relationship between cardiac lymph and arterial plasma free palmitate and triglycerides was studied in anesthetized dogs. [14C]Sucrose, infused at a constant rate in a femoral vein, appeared in the lymph at 90% of its arterial concentration within 60 min. On the other hand, when [1-14C]palmitate was infused at the same rate and at the same site, the ratio of lymph to arterial plasma 14C-labelled free fatty acids (FFA) was only 21% at 60 min and 25% at 120 min, even though the concentrations of endogenous FFA in lymph and arterial plasma were the same. The ratio reached 90% only 24 h after a bolus injection of [3H]palmitate. [1-14C]Palmitate in the lymph triglyceride fraction was only 8% of that in plasma. Although the lymph composition may be influenced by the metabolism of heart muscle, cardiac adipose tissue, and serum lipoproteins, these results indicate the presence of a pool of myocardial fatty acids which may be partly located in the interstitial spaces.

scholarly journals Snow Stratigraphy and Water Equivalence Measured With an Active Microwave System

1980 ◽  
Vol 26 (94) ◽  
pp. 225-233
Author(s):  
D. A. Ellerbruch ◽  
H. S. Boyne
Keyword(s):  
Electromagnetic Scattering ◽  
Direct Determination ◽  
Snow Pack ◽  
Frequency Range ◽  
Microwave Radar ◽  
Snow Stratigraphy ◽  
Microwave System ◽  
The Relationship ◽  
System Operating

AbstractThis paper reports on research on the relationship between the electromagnetic scattering properties and physical properties of snow-pack. An FM-CW active microwave radar system operating in the frequency range 8-12 GHz is used to scatter electromagnetic radiation from surface and subsurface stratigraphic layers in the snow-pack. The amplitude of the scattered radiation as a function of depth in the snow-pack can be correlated with such physical characteristics as density, hardness, stratigraphy, and moisture content. A direct determination of snow-pack water equivalence can be made from these observations.

scholarly journals The effects of changing meteorological parameters on fatal aortic catastrophes

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Brigitta Szilágyi ◽  
Márton Berczeli ◽  
Attila Lovas ◽  
Zoltán Oláh ◽  
Klára Törő ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Process Model ◽  
Meteorological Parameters ◽  
Main Tool ◽  
Environmental Parameters ◽  
Aortic Aneurysms ◽  
Occurrence Rate ◽  
Causal Connection ◽  
Cox Process ◽  
The Relationship

Abstract Background Over the span of the last decade, medical research has been increasingly putting greater emphasis on the study of meteorological parameters due to their connection to cardiovascular diseases. The main goal of this study was to explore the relationship between fatal aortic catastrophes and changes in atmospheric pressure and temperature. Methods We used a Cox process model to quantify the effects of environmental factors on sudden deaths resulting from aortic catastrophes. We used transfer entropy to draw conclusion about the causal connection between mortality and meteorological parameters. Our main tool was a computer program which we developed earlier in order to evaluate the relationship between pulmonary embolism mortality and weather on data sets comprised of aortic aneurysm (AA) and acute aortic dissection (AAD) cases, where one of these two medical conditions had led to fatal rupture of the aorta. Our source for these cases were the autopsy databases of Semmelweis University, from the time period of 1994 to 2014. We have examined 160 aneurysm and 130 dissection cases in relation to changes in meteorological parameters. The algorythm implemented in our program is based on a non-parametric a Cox process model. It is capable of splitting slowly varying unknown global trends from fluctuations potentially caused by weather. Furthermore, it allows us to explore complex non-linear interactions between meteorological parameters and mortality. Results Model measures the relative growth of the expected number of events on the nth day caused by the deviation of environmental parameters from its mean value. The connection between ruptured aortic aneurysms (rAA) and changes in atmospheric pressure is more significant than their connection with mean daily temperatures. With an increase in atmospheric pressure, the rate of rAA mortality also increased. The effects of meteorological parameters were weaker for deaths resulting from acute aortic dissections (AAD), although low mean daily temperatures increased the intensity of occurrence for AAD-related deaths. Conclusion The occurrence rate of fatal aortic catastrophes showed a slight dependence on the two examined parameters within our groups.

The effect of breed on the relationship between food composition and the efficiency of protein utilisation in young pigs

1993 ◽  
Vol 1993 ◽  
pp. 62-62
Author(s):  
D Dotas ◽  
I Kyriazakis ◽  
D H Anderson ◽  
G C Emmans
Keyword(s):  
Energy Supply ◽  
Food Composition ◽  
Genetic Effects ◽  
Protein Deposition ◽  
Pig Breeds ◽  
Material Efficiency ◽  
Young Pigs ◽  
Constant Rate ◽  
Protein Supply ◽  
The Relationship

It has been suggested (Kyriazakis and Emmans, 1992a, b) that the material efficiency with which the pig can retain protein (ep), is directly proportional to the energy:protein ratio of the diet (R), so that ep = k.R. This hypothesis accounts for the finding that the rate of protein deposition can sometimes be increased by increasing the energy supply at a constant rate of protein supply.It is also possible that the constant of proportionality, k, is a genetic variable, although it was proposed, partly for the sake of simplicity, that there would be no genetic effects on the value of k. To test the propositions: (i) that ep is proportional to R, and (ii) that k does not differ between genotypes, an experiment was designed and carried out on two pig breeds which were expected to be very different from each other.

Dielectric Property of Laminated AlN/BN Ceramic Composites

2009 ◽  
Vol 620-622 ◽  
pp. 359-362
Author(s):  
Tao Zhang ◽  
Hai Yun Jin ◽  
Rui Zhou ◽  
Ji Feng Zhao ◽  
Zhi Hao Jin
Keyword(s):  
Dielectric Property ◽  
Dielectric Loss ◽  
Low Frequency ◽  
Ceramic Composites ◽  
Space Charge Polarization ◽  
Frequency Range ◽  
Pressing Temperature ◽  
Polarization Mechanism ◽  
The Relationship ◽  
Dielectric Loss Increase

The relationship between the processing technology and the dielectric property of the laminated AlN/h-BN ceramic composites has been studied. The results showed that the main polarization mechanism of laminated ceramic composites in low frequency range is space charge polarization at the interface of AlN layer and BN layer. Due to the affection of porosity, the permittivity increases and the dielectric loss decreases with increasing the hot pressing temperature. The permittivity increases and the dielectric loss decreases with increasing thickness ratio of different layer., Both permittivity and dielectric loss increase with increasing the content of AlN doping in BN layer.

scholarly journals Recovery of Flexible Polyurethane Foam Waste for Efficient Reuse in Industrial Formulations

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1533 ◽  
Author(s):  
Gabriel Kiss ◽  
Gerlinde Rusu ◽  
Francisc Peter ◽  
Ionuț Tănase ◽  
Geza Bandur
Keyword(s):  
Polyurethane Foam ◽  
Atmospheric Pressure ◽  
Air Permeability ◽  
Hydroxyl Number ◽  
Pu Foam ◽  
Flexible Polyurethane Foam ◽  
Flexible Polyurethane ◽  
The Relationship ◽  
Pu Foams ◽  
Glycolysis Process

Ester polyurethane (PU) foam waste was reacted at atmospheric pressure in an autoclave and using microwaves with diethylene glycol (DEG) at different PU/DEG ratios in the presence of diethanolamine as a catalyst to find the glycolysis conditions that allow for the improved recovery of the PU foam waste and enable the recycling of the whole glycolysis product in foam formulations suitable for industrial application. The recycled polyol was characterized by dynamic viscosity, hydroxyl number, water content, and density, while thermal stability was assessed using thermogravimetric analysis. In the PU foam formulation, 1% and 5% of the glycolyzed material was reused. The relationship between the reuse level of the recycled polyol and the physical properties of the foam was thoroughly investigated. It was observed that both hardness and air flow decreased with increasing recycled polyol content, particularly for the polyester type foam, while tensile strength and compression strength increased. Depending on the amount of recycled polyol and catalyst used, polyether-based foams could be obtained with a low air permeability, needed in special applications as sealed foams, or with higher air permeability desirable for comfort PU foams. The results open the way for further optimization studies of industrial polyurethane foam formulations using a glycolysis process without any separation stage.

scholarly journals Staircase, rest contractions, and potentiation in the isolated rat heart

1962 ◽  
Vol 202 (4) ◽  
pp. 636-640 ◽  
Author(s):  
F. L. Meijler
Keyword(s):  
Cycle Length ◽  
Rest Period ◽  
Isolated Rat Heart ◽  
Stimulation Rate ◽  
Rat Hearts ◽  
Constant Rate ◽  
Theoretical Evidence ◽  
The Relationship ◽  
Isotonic Contractions ◽  
Isolated Rat

Variation in amplitude of isotonic contractions of intact isolated rat hearts, following changes in cycle length, were studied. It was found that a staircase-like phenomenon resembling the original Bowditch effect cannot be evoked in a intact mammalian heart without special measures, such as adding acetylcholine to the perfusion fluid. A steady state relation of rate to amplitude of isotonic contractions was demonstrated. Potentiation of contractility can be originated by sudden changes in stimulation rate. A rest period preceding the changes in stimulation rate does not change the potentiation found originally. At a constant rate the amplitude of a contraction is determined by the preceding cycle length. This relation has been called restitution. Theoretical evidence is presented in an attempt to demonstrate that restitution and potentiation are due to the same process. It can be concluded that Bowditch's staircase does not play a role in the relationship between cycle length and contractility in intact hearts and the statement that restitution and potentiation are due to the same process offers an opportunity to describe all effects of changes in cycle length on isotonic contractions as one phenomenon.

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