Practical method of calculating the stability of plane flexure of beams with arbitrary constraints at the supports under arbitrary loads

1981 ◽  
Vol 17 (1) ◽  
pp. 80-85
Author(s):  
M. Kh. Mullagulov
Keyword(s):  
Practical Method ◽  
Plane Flexure ◽  
The Stability

Seismic stability analyses of reinforced tapered landfill cover systems considering seepage forces

2018 ◽  
Vol 36 (4) ◽  
pp. 361-372 ◽  
Author(s):  
Afshin Khoshand ◽  
Ali Fathi ◽  
Milad Zoghi ◽  
Hamidreza Kamalan
Keyword(s):  
Parametric Study ◽  
Limit Equilibrium ◽  
Practical Method ◽  
Seismic Stability ◽  
Design Parameters ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System ◽  
The Stability

One of the most common and economical methods for waste disposal is landfilling. The landfill cover system is one of the main components of landfills which prevents waste exposure to the environment by creating a barrier between the waste and the surrounding environment. The stability and integrity of the landfill cover system is a fundamental part of the design, construction, and maintenance of landfills. A reinforced tapered landfill cover system can be considered as a practical method for improving its stability; however, the simultaneous effects of seismic and seepage forces in the reinforced tapered landfill cover system have not been studied. The current paper provides a solution based on the limit equilibrium method in order to evaluate the stability of a reinforced tapered landfill cover system under seismic and seepage (both horizontal and parallel seepage force patterns) loading conditions. The proposed analytical approach is applied to different design cases through parametric study and the obtained results are compared to those derived from literature. Parametric study is performed to illustrate the sensitivity of the safety factor (FS) to the different design parameters. The obtained results reveal that parameters which describe the geometry have limited effects on the stability of the landfill cover system in comparison to the rest of the studied design parameters. Moreover, the comparisons between the derived results and available methods demonstrate good agreement between obtained findings with those reported in the literature.

A Practical Method for Estimating Percent Body Fat of Adult Mentally Retarded Males

1987 ◽  
Vol 4 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Luke E. Kelly ◽  
James H. Rimmer
Keyword(s):  
Body Fat ◽  
Standard Error ◽  
Mentally Retarded ◽  
Practical Method ◽  
Prediction Equation ◽  
Stepwise Multiple Regression ◽  
Percent Body Fat ◽  
Criterion Measure ◽  
The Stability ◽  
New Equation

The subjects were 170 moderately and severely mentally retarded men who were divided into two groups. The first group was used to formulate a new prediction equation and the second group was used to cross-validate and ascertain the stability of the derived equation. The prediction equation, employing waist and forearm circumferences, height and weight as predictors, and estimated percent body fat calculated by the generalized regression equation of Jackson and Pollock (1978) as the criterion measure, was formulated using a stepwise multiple regression analysis. A multiple R value of .86 was obtained for the derived equation with a standard error of estimate value of 3.35. The equation was cross-validated on the second sample to ascertain its stability. An r of .81 and a standard error of estimate of 4.41 was obtained between the subjects’ estimated percent body fat, using the new equation, and the criterion measure. This simplified equation provides practitioners with an accurate, reliable, and inexpensive method of estimating percent body fat for adult mentally retarded males.

Rotordynamic Evaluation of Centrifugal Compressor Using Electromagnetic Exciter

2011 ◽  
Author(s):  
Naohiko Takahashi ◽  
Yohei Magara ◽  
Mitsuhiro Narita ◽  
Haruo Miura
Keyword(s):  
High Pressure ◽  
Frequency Response ◽  
Damping Ratio ◽  
Practical Method ◽  
Magnetic Bearing ◽  
Response Functions ◽  
Mathematical Operation ◽  
Frequency Response Functions ◽  
Calculation Results ◽  
The Stability

Since heavier gases exert larger effects on rotordynamic stability, stability evaluation is important in developing or designing high-pressure compressors. To evaluate the rotor stability during operation, an excitation test using a magnetic bearing is the most practical method. In stability analysis, labyrinth seals can produce significant cross-coupling forces, which particularly reduce the damping ratio of the first forward mode. Therefore, forward modes should be distinguished from backward modes in the excitation test. One method that excites only the forward modes, not the backward modes (and vice versa), is the use of a rotating excitation. In this method, the force is simultaneously applied to two axes to excite the rotor in circular orbits. Two trigonometric functions, i.e., cosine and sine functions, are used to generate this rotation force. Another method is the use of a unidirectional excitation and a mathematical operation to distinguish the forward whirl from the backward whirl. In this method, a directional frequency response function that separates the two modes in the frequency domain is obtained from four frequency response functions by using a complex number expression for the rotor motion. In this study, the latter method was employed to evaluate the rotor stability of a high-pressure compressor. To obtain the frequencies and damping ratios of the eigenvalues, the curve fitting based on system identification methods, such as the prediction error method, was introduced for the derived frequency response functions. Firstly, these methods were applied to a base evaluation under a low-pressure gas operation, in which the stability mainly depends on the bearing property. Using the obtained results, the bearing coefficients were estimated. Next, the same methods were applied to stability evaluations under high-pressure gas operations. The destabilizing forces were also estimated from the test results and compared with the calculation results.

DETERMINATION OF T.N.T. (2,4,6-TRINITROTOLUENE) IN AIR

1941 ◽  
Vol 19b (3) ◽  
pp. 86-89 ◽  
Author(s):  
Kingsley Kay
Keyword(s):  
Sodium Hydroxide ◽  
Field Tests ◽  
Practical Method ◽  
Optimum Conditions ◽  
Accurate Comparison ◽  
The Stability ◽  
Red Coloration

A practical method for determining the concentration of T.N.T. in workroom atmospheres has been developed and has been given successful field tests. The accuracy of the method described is approximately ± 10%. The method is a comparative one, depending upon the red coloration produced when 2,4,6-trinitrotoluene in acetone is treated with a solution of sodium hydroxide in water. The stability of the coloration has been studied and the optimum conditions of temperature and concentrations of reactants have been determined. In addition the range of colour that allows the most accurate comparison has been evaluated. Minor refinements are at present in progress with a view to increasing the accuracy of the test.

scholarly journals Replicative indwelling: Mitigating lost knowledge through accelerated experiential exposure

2016 ◽  
Vol 4 (2) ◽  
pp. 110-127
Author(s):  
Benjamin Aaron Stahl ◽  
Brian Buckles
Keyword(s):  
Professional Development ◽  
Intellectual Capital ◽  
Practical Method ◽  
Organizational Success ◽  
Years Of Experience ◽  
Aging Workforce ◽  
The Stability

An aging workforce presents a serious threat to the stability and continuity of an organization as that workforce takes with it into retirement years of experience, insight, and knowledge. As a result, organizations are faced with the challenge of how to mitigate the loss of intellectual capital during the process of transferring knowledge to the remaining workforce in order to maximize the chances of continued organizational success. This paper offers a practical method of application for intra-organizational professional development that seeks to mitigate lost knowledge by introducing a process referred to as Accelerated Experiential Exposure, as well as an epistemological frame from which it is presented, referred to as Replicative Indwelling.

Controlling Exhaustion of Reactive Dyes on Wool by Microencapsulation with Liposomes

1997 ◽  
Vol 67 (7) ◽  
pp. 537-541 ◽  
Author(s):  
J. I. N. R. Gomes ◽  
M. C. Genovez ◽  
R. Hrdina
Keyword(s):  
Reactive Dyes ◽  
Practical Method ◽  
Reactive Dye ◽  
Mechanical Agitation ◽  
Commercial Products ◽  
The Stability ◽  
Lecithin Liposome

Exhaustion of a reactive dye for wool is studied in the presence of liposome-forming compounds (lecithin). Both analytical and commercial products are used as a source for the lecithin. Liposome formation is tested with different preparation procedures (ultrasound and mechanical agitation), and the stability is evaluated under different conditions of time, temperature, and the presence pf a tensoactive product. The effect of these different conditions and the variation of liposome concentration on exhaustion and levelness is presented. A practical method for dyeing wool with reactive dyes using liposome-forming compounds is proposed based on the results.

Improved Statistical Linearization for Analysis and Control of Nonlinear Stochastic Systems: Part I: An Extended Statistical Linearization Technique

1981 ◽  
Vol 103 (1) ◽  
pp. 14-21 ◽  
Author(s):  
J. J. Beaman ◽  
J. Karl Hedrick
Keyword(s):  
Stochastic Systems ◽  
Practical Method ◽  
Order System ◽  
Statistical Linearization ◽  
Linearization Technique ◽  
Expansion Technique ◽  
Mean Square Response ◽  
Simplifying Assumptions ◽  
The Stability ◽  
And Control

A practical method of improving the accuracy of the Gaussian statistical linearization technique is presented. The method uses a series expansion of the unknown probability density function which includes up to fourth order terms. It is shown that by the use of the Gram-Charlier expansion a simple generating function can be derived to evaluate analytically the integrals required. It is also shown how simplifying assumptions can be used to substantially reduce the required extra equations, e.g. symmetric or assymetric and single input nonlinearities. It is also shown that the eigenvalues of the statistically linearized system can be used to estimate the stability and speed of response of the nonlinear system. The reduced expansion technique is applied to first and second order nonlinear systems and the predicted mean square response is compared to the Gaussian statistical linearization and the exact solution. The prediction of the time response of the mean of a nonlinear first order system by the use of the statistically linearized eigenvalues is compared to a 300 run Monte Carlo digital solution.

Rotordynamic Evaluation of Centrifugal Compressor Using Electromagnetic Exciter

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Naohiko Takahashi ◽  
Yohei Magara ◽  
Mitsuhiro Narita ◽  
Haruo Miura
Keyword(s):  
High Pressure ◽  
Frequency Response ◽  
Damping Ratio ◽  
Practical Method ◽  
Magnetic Bearing ◽  
Response Functions ◽  
Mathematical Operation ◽  
Frequency Response Functions ◽  
Calculation Results ◽  
The Stability

Since heavier gases exert larger effects on rotordynamic stability, stability evaluation is important in developing or designing high-pressure compressors. To evaluate the rotor stability during operation, an excitation test using a magnetic bearing is the most practical method. In stability analysis, labyrinth seals can produce significant cross coupling forces, which particularly reduce the damping ratio of the first forward mode. Therefore, forward modes should be distinguished from backward modes in the excitation test. One method that excites only the forward modes, not the backward modes (and vice versa), is the use of a rotating excitation. In this method, the force is simultaneously applied to two axes to excite the rotor in circular orbits. Two trigonometric functions, i.e., cosine and sine functions, are used to generate this rotation force. Another method is the use of a unidirectional excitation and a mathematical operation to distinguish the forward whirl from the backward whirl. In this method, a directional frequency response function that separates the two modes in the frequency domain is obtained from four frequency response functions by using a complex number expression for the rotor motion. In this study, the latter method was employed to evaluate the rotor stability of a high-pressure compressor. To obtain the frequencies and damping ratios of the eigenvalues, the curve fitting based on system identification methods, such as the prediction error method, was introduced for the derived frequency response functions. Firstly, these methods were applied to a base evaluation under a low-pressure gas operation, in which the stability mainly depends on the bearing property. Using the obtained results, the bearing coefficients were estimated. Next, the same methods were applied to stability evaluations under high-pressure gas operations. The destabilizing forces were also estimated from the test results and compared with the calculation results.

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