Intracranial and Intraocular Pressure Gradient and Glaucoma: A Retrospective Point of View

2019 ◽  
pp. 39-43
Author(s):  
Xiangxiang Liu ◽  
Diya Yang ◽  
Ningli Wang
Keyword(s):  
Intraocular Pressure ◽  
Pressure Gradient ◽  
Point Of View

scholarly journals Dorsomedial/Perifornical Hypothalamic Stimulation Increases Intraocular Pressure, Intracranial Pressure, and the Translaminar Pressure Gradient

2012 ◽  
Vol 53 (11) ◽  
pp. 7328 ◽  
Author(s):  
Brian C. Samuels ◽  
Nathan M. Hammes ◽  
Philip L. Johnson ◽  
Anantha Shekhar ◽  
Stuart J. McKinnon ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Intracranial Pressure ◽  
Pressure Gradient ◽  
Hypothalamic Stimulation

scholarly journals Theoretical Evaluation of Graphene Membrane Performance for Hydrogen Separation Using Molecular Dynamic Simulation

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 110 ◽  
Author(s):  
Mahdi Nouri ◽  
Kamran Ghasemzadeh ◽  
Adolfo Iulianelli
Keyword(s):  
Pressure Gradient ◽  
Molecular Dynamic ◽  
Molecular Mechanisms ◽  
Gas Diffusion ◽  
Point Of View ◽  
Theoretical Point ◽  
Pore Density ◽  
Theoretical Evaluation ◽  
Membrane Performance ◽  
Graphene Membranes

The main purposes of this study are to evaluate the performance of graphene membranes in the separation/purification of hydrogen from nitrogen from a theoretical point of view using the molecular dynamic (MD) simulation method, and to present details about molecular mechanisms of selective gas diffusion through nanoscale pores of graphene membranes at the simulated set conditions. On the other hand, permeance and perm-selectivity are two significant parameters of such a membrane that can be controlled by several variables such as pressure gradient, pore density, pore layer angles etc. Hence, in this work, the hydrogen and nitrogen permeating fluxes as well as the H2/N2 ideal perm-selectivity are investigated from a theoretical point of view in a two-layer nanoporous graphene (NPG) membrane through classical MD simulations, wherein the effects of pressure gradient, pore density, and pore angle on the NPG membrane performance are evaluated and discussed. Simulation outcomes suggest that hydrogen and nitrogen permeating fluxes increase as a consequence of an increment of pressure gradient across the membrane and pore density.

A mathematical analysis for the blade coating process of Oldroyd 4-constant fluid

2019 ◽  
Vol 39 (9) ◽  
pp. 852-860 ◽  
Author(s):  
Hasan Shahzad ◽  
Xinhua Wang ◽  
Muhammad Mughees ◽  
Muhammad Sajid ◽  
Nasir Ali
Keyword(s):  
Pressure Gradient ◽  
Numerical Technique ◽  
Point Of View ◽  
Rheological Parameters ◽  
Coating Process ◽  
Dimensionless Form ◽  
Velocity Pressure ◽  
Linear Boundary Value Problem ◽  
Blade Coating

AbstractA mathematical study of an Oldroyd 4-constant fluid for a blade coating process is studied in this paper. The results for plane as well as exponential coaters are analyzed. Suitable dimensionless variables are used to convert the model governing equations into dimensionless form. Lubrication approximation theory is applied to simplify the dimensionless form of governing partial differential equations. The well-known numerical technique known as the shooting method is used to solve the non-linear boundary value problem. Influence of the involved rheological parameters on the blade coating process is analyzed. From an engineering point of view, load on the blade and pressure are important outcomes of the present study as they ensure the thickness and quality of coating and enhance the life of the substrate. The effects of material parameters on load, thickness, velocity, pressure and pressure gradient are discussed. Obtained results for velocity, pressure gradient and pressure distribution are shown graphically, whereas load and thickness are expressed in a tabulated form.

scholarly journals The forces on a body placed in a curved or converging stream of fluid

1928 ◽  
Vol 120 (785) ◽  
pp. 260-283 ◽  
Keyword(s):  
Wind Tunnel ◽  
Pressure Gradient ◽  
Static Pressure ◽  
Practical Interest ◽  
Point Of View ◽  
The Body ◽  
Primary Object ◽  
Body Experiences ◽  
Measured Resistance ◽  
Hydrodynamical Theory

The force which a body experiences when placed in a converging stream of fluid has a certain practical interest in aeronautics because the flow in the centre of a parallel-walled wind tunnel is of this type. The convergence is due to the retardation of a layer of air close to the walls. This retarded layer increases in thickness as the air passes down the channel, thus causing a corresponding increase in the velocity in the central part of the channel. This increase in velocity is associated with a decrease in pressure in accordance with Bernouilli’s equation, the pressure in a Pitot tube being very nearly constant down the channel at all points outside the retarded layer. In measuring the resistance of models of airships it has been customary to correct the observed readings by subtracting what is called the “horizontal buoyancy,” i. e. , the force which would act on the body if the air were a stationary fluid in which the existing pressure gradient down the channel was maintained by some external force like gravity. Expressed mathematically, if dp / dx is the pressure gradient, i. e. , the gradient of static pressure in the channel, and V the volume of the body, the “horizontal buoyancy” is — V dp / dx . This correction to the measured resistance of an airship model is believed to be approximately correct from the point of view of wind tunnel practice, and the primary object of the present work was to find out how far it is justified from the point of view of hydrodynamical theory.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Activated Prominences; Mechanisms for Activation and Eruption

1979 ◽  
Vol 44 ◽  
pp. 307-313
Author(s):  
D.S. Spicer
Keyword(s):  
Pressure Gradient ◽  
Density Gradient ◽  
Current Density ◽  
Convective Instability ◽  
Tearing Mode ◽  
Magnetic Shear ◽  
Long Wavelength ◽  
Ideal Mhd ◽  
Gradient Change ◽  
Accelerated Particles

A possible relationship between the hot prominence transition sheath, increased internal turbulent and/or helical motion prior to prominence eruption and the prominence eruption (“disparition brusque”) is discussed. The associated darkening of the filament or brightening of the prominence is interpreted as a change in the prominence’s internal pressure gradient which, if of the correct sign, can lead to short wavelength turbulent convection within the prominence. Associated with such a pressure gradient change may be the alteration of the current density gradient within the prominence. Such a change in the current density gradient may also be due to the relative motion of the neighbouring plages thereby increasing the magnetic shear within the prominence, i.e., steepening the current density gradient. Depending on the magnitude of the current density gradient, i.e., magnetic shear, disruption of the prominence can occur by either a long wavelength ideal MHD helical (“kink”) convective instability and/or a long wavelength resistive helical (“kink”) convective instability (tearing mode). The long wavelength ideal MHD helical instability will lead to helical rotation and thus unwinding due to diamagnetic effects and plasma ejections due to convection. The long wavelength resistive helical instability will lead to both unwinding and plasma ejections, but also to accelerated plasma flow, long wavelength magnetic field filamentation, accelerated particles and long wavelength heating internal to the prominence.

How a sheperd guides a sheep herd?

1984 ◽  
Vol 75 ◽  
pp. 331-337
Author(s):  
Richard Greenberg
Keyword(s):  
Point Of View ◽  
Single Ring ◽  
Damping Effects ◽  
Ring Particle

ABSTRACTThe mechanism by which a shepherd satellite exerts a confining torque on a ring is considered from the point of view of a single ring particle. It is still not clear how one might most meaningfully include damping effects and other collisional processes into this type of approach to the problem.

An Attack on the Contamination Problem in the Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 368-368
Author(s):  
J. J. Kelsch ◽  
A. Holtz
Keyword(s):  
Electron Microscope ◽  
Pressure Gradient ◽  
Ionization Potential ◽  
Simple Solution ◽  
Specimen Surface ◽  
Contamination Rate ◽  
Local Pressure ◽  
High Ionization ◽  
Hydrocarbon Molecules ◽  
Contamination Problem

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Radiation Damage in Ceramics

1982 ◽  
Vol 40 ◽  
pp. 600-603
Author(s):  
T. E. Mitchell ◽  
M. R. Pascucci ◽  
R. A. Youngman
Keyword(s):  
Radiation Damage ◽  
Outer Space ◽  
Point Of View ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Storage Media ◽  
Transmission Electron ◽  
Fundamental Point ◽  
Small Defect ◽  
Present Understanding

1. Introduction. Studies of radiation damage in ceramics are of interest not only from a fundamental point of view but also because it is important to understand the behavior of ceramics in various practical radiation enyironments- fission and fusion reactors, nuclear waste storage media, ion-implantation devices, outer space, etc. A great deal of work has been done on the spectroscopy of point defects and small defect clusters in ceramics, but relatively little has been performed on defect agglomeration using transmission electron microscopy (TEM) in the same kind of detail that has been so successful in metals. This article will assess our present understanding of radiation damage in ceramics with illustrations using results obtained from the authors' work.

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