scholarly journals Introduction of active and passive control options for hydrostatic pressure chambers

2020 ◽  
Vol 10 (2) ◽  
pp. 155-159
Author(s):  
Sándor Gergő Tóth ◽  
György Takács
Keyword(s):  
Hydrostatic Pressure ◽  
Critical Points ◽  
Passive Control ◽  
Pressure Control ◽  
Design Methods ◽  
Proper Selection ◽  
Pressure Sensitive ◽  
Control Options ◽  
Bearing Stiffness ◽  
Selection Of

One of the critical points in the design of hydrostatic bearings is the proper selection of the pressure control of the bearing recess, yet the design methods do not pay much attention to this. In addition to conventional solutions, the control of the pressure recesses can be accomplished by the use of volumetric and pressure-sensitive valves in the hydraulics to achieve greater bearing stiffness. A new way of regulating can also be the regulation of the recess with proportional valves.

On the Optimization of the Stiffness of Externally Pressurized Bearings

1962 ◽  
Vol 84 (1) ◽  
pp. 119-122 ◽  
Author(s):  
Marvin T. S. Ling
Keyword(s):  
Optimum Condition ◽  
Film Thickness ◽  
Incompressible Fluid ◽  
Compressible Fluid ◽  
Theoretical Studies ◽  
Proper Selection ◽  
Supply Pressure ◽  
Bearing Stiffness ◽  
Selection Of

This paper presents theoretical studies of the method of optimization of the stiffness of externally pressurized bearings. When an externally pressurized bearing is designed to operate at any given film thickness, it is found that the maximum bearing stiffness can be obtained by proper selection of the value of the ratio of recess to supply pressure, Pr/Ps. While various values of Pr/Ps can be attained by either varying the restrictor constant for a given film thickness or varying the film thickness for a given restrictor constant, the important quantity to vary in determining the optimum condition is the restrictor constant rather than the film thickness. For an incompressible fluid, the Pr/Ps value for which the bearing stiffness is optimized depends only on the type of compensation used, while for a compressible fluid it is slightly affected by exhaust pressure.

Analytical and Experimental Study of Externally Pressurized Air Lubricated Journal Bearings

1962 ◽  
Vol 84 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Jason R. Lemon
Keyword(s):  
Journal Bearing ◽  
Design Parameters ◽  
Radial Clearance ◽  
Proper Selection ◽  
One Dimensional ◽  
Supply Pressure ◽  
Bearing Stiffness ◽  
Bearing Design ◽  
Gas Journal Bearing ◽  
Selection Of

A simplified analysis for calculating the characteristics, such as stiffness, flow, and load of an externally pressurized gas journal bearing, is obtained through a standard one-dimensional flow approach altered to take into account the effect of circumferential pressure variations. From this analysis, it is revealed that bearing stiffness has an optimum which, it is further shown, can be chosen through a proper selection of bearing design parameters, such as radial clearance, upstream resistor, and supply pressure. As the analysis is developed each assumption is experimentally verified. The final predictions of the analysis are also verified. It is felt that the analysis is sufficiently simple to allow comparison of many different bearing configurations, while sufficiently complete to compare very well against experimental measurements in all respects. A comparison is made between the recessed and nonrecessed bearing.

Meriel Talbot and the Society for the Overseas Settlement of British Women, 1919–1937

2017 ◽  
Vol 10 (1) ◽  
pp. 32-52
Author(s):  
Bonnie White
Keyword(s):  
Domestic Service ◽  
Agricultural Workers ◽  
British Government ◽  
Early Failure ◽  
Proper Selection ◽  
Domestic Servants ◽  
Female Workers ◽  
Female Migrants ◽  
Post War ◽  
Selection Of

In 1917 the British government began making plans for post-war adjustments to the economy, which included the migration of surplus women to the dominions. The Society for the Overseas Settlement of British Women was established in 1920 to facilitate the migration of female workers to the dominions. Earlier studies have argued that overseas emigration efforts purposefully directed women into domestic service as surplus commodities, thus alleviating the female ‘surplus’ and easing economic hardships of the post-war period. This article argues that as Publicity Officer for the SOSBW, Meriel Talbot targeted women she believed would be ideal candidates for emigration, including former members of the Women's Land Army and affiliated groups. With the proper selection of female migrants, Talbot sought to expand work opportunities for women in the dominions beyond domestic service, while reducing the female surplus at home and servicing the connection between state and empire. Dominion authorities, whose demands for migrant labour vacillated between agricultural workers during the war years and domestic servants after 1920, disapproved of Talbot's efforts to migrate women for work in agriculture. Divergent policies led to the early failure of the SOSBW in 1923.

scholarly journals Design Concepts for NiTiNOL Wires to Function as a Sensor

2021 ◽  
Author(s):  
D. Josephine Selvarani Ruth
Keyword(s):  
Shape Memory Alloy ◽  
Electrical Resistance ◽  
Nickel Titanium ◽  
The Other ◽  
Sensing Element ◽  
Proper Selection ◽  
Design Concepts ◽  
Mechanical Element ◽  
Selection Of ◽  
Inverse Hysteresis

AbstractNickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires’ nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system’s output by introducing inverse hysteresis to the wires through the passive mechanical element.

A Non-Normality Measure of the Condition Number for Monitoring and Control

1997 ◽  
Vol 119 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Kunsoo Huh ◽  
Jeffrey L. Stein
Keyword(s):  
Optimal Control ◽  
Condition Number ◽  
Minimization Problem ◽  
Monitoring And Control ◽  
Proper Selection ◽  
Modal Structure ◽  
L2 Norm ◽  
And Control ◽  
Normality Measure ◽  
Selection Of

Because the behavior of the condition number can have highly steep and multi-modal structure, optimal control and monitoring problems based on the condition number cannot be easily solved. In this paper, a minimization problem is formulated for κ2(P), the condition number of an eigensystem (P) of a matrix in terms of the L2 norm. A new non-normality measure is shown to exist that guarantees small values for the condition number. In addition, this measure can be minimized by proper selection of controller and observer gains. Application to the design of well-conditioned controller and observer-based monitors is illustrated.

scholarly journals Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

2016 ◽  
Vol 61 (1) ◽  
pp. 353-360 ◽  
Author(s):  
B. Dybowski ◽  
J. Szymszal ◽  
Ł. Poloczek ◽  
A. Kiełbus
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Chemical Composition ◽  
Aluminium Alloys ◽  
Mg Alloys ◽  
High Electrical Conductivity ◽  
Transportation Industry ◽  
Proper Selection ◽  
Ti Addition ◽  
Selection Of

Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the influence of alloys chemical composition on their properties. It has been revealed that Si and Ti addition decreases electrical conductivity of the Al-Si-Mg alloys, while Na addition increases it. The mechanical properties of the investigated alloys are decreased by both silicon and iron presence. Sodium addition increases ductility of the Al-Si-Mg alloys.

scholarly journals Hydrogen Gas Sensors Fabricated on Atomically Flat 4H-SiC Webbed Cantilevers

2008 ◽  
Vol 600-603 ◽  
pp. 1199-1202 ◽  
Author(s):  
Philip G. Neudeck ◽  
David J. Spry ◽  
Andrew J. Trunek ◽  
Laura J. Evans ◽  
Liang Yu Chen ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Rapid Detection ◽  
Hydrogen Gas ◽  
Current Gain ◽  
Proper Selection ◽  
Hydrogen Gas Sensors ◽  
Sensor Current ◽  
Atomically Flat ◽  
Initial Results ◽  
Selection Of

This paper reports on initial results from the first device tested of a “second generation” Pt-SiC Schottky diode hydrogen gas sensor that: 1) resides on the top of atomically flat 4H-SiC webbed cantilevers, 2) has integrated heater resistor, and 3) is bonded and packaged. With proper selection of heater resistor and sensor diode biases, rapid detection of H2 down to concentrations of 20 ppm was achieved. A stable sensor current gain of 125 ± 11 standard deviation was demonstrated during 250 hours of cyclic test exposures to 0.5% H2 and N2/air.

Available Energy: I. Gibbs Revisited; II. Gibbs Extended

1999 ◽  
Author(s):  
Richard A. Gaggioli ◽  
David H. Richardson ◽  
Anthony J. Bowman ◽  
David M. Paulus
Keyword(s):  
The Body ◽  
Nonequilibrium Condition ◽  
Balance Equations ◽  
Proper Selection ◽  
Additive Property ◽  
Property Relations ◽  
Available Energy ◽  
Dead State ◽  
Energy Equilibrium ◽  
Selection Of

Abstract The concept of available energy, as defined by Gibbs (1873b) is revisited. He gave representations of available energy for two circumstances. The first was the available energy of a “body,” for the case when a body, alone, is in a nonequilibrium condition and therefore has energy available. In turn, he presented the available energy of “the body and medium,” for the energy which is available because a body is not in equilibrium with some arbitrarily specified medium. Gibbs’ representations were graphical. Since Gibbs, representations with formulas have been developed and are common, for the “available energy of body and medium.” Gaggioli (1998a, b) has developed formulas which are more general, to represent “the available energy of the body (alone)” and to assign an exergy to subsystems of the body as a measure of each sub-system’s contribution to the available energy. In contrast to the available energy, exergy is an additive property, so that balance equations can be written. And the formulas are independent from any “medium,” which is important both theoretically and practically — because of its relevance to proper selection of “the dead state.” These issues are discussed and extended, after reviewing Gibbs development of available energy and additional concepts which he introduced, such as “available vacuum” and “capacity for entropy.” It is argued that these “availabililty” and “capacity” concepts are all equivalent to one another. In turn, because of interconvertability, it is seen that available energy is something more fundamental than “maximum useful work.” Furthermore, it is illustrated that available energy, equilibrium and stability, and thermostatic property relations are relative, to “constraints.”

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