A Statistical Appraisal of the Prot Method for Determination of Fatigue Endurance Limit

1957 ◽  
Vol 24 (2) ◽  
pp. 214-218
Author(s):  
W. A. Hijab

Abstract A statistical analysis of the precision of the estimate of endurance limit as determined by the Prot method is carried out. This analysis shows that the Prot method cannot achieve a great saving in the number of specimens required, for its statistical efficiency is found to be even less than that of its other two competitors, the probit and staircase methods. This fact, coupled with serious objections to its assumptions, renders its usefulness highly questionable. A secondary result of the analysis is that the optimum efficiency of the Prot method is achieved when only two rates of increase of stress, as widely separated as possible, are used. A derivation of a general formula, of which the Prot method is a particular case and which makes explicit all assumptions necessary for the valid derivation of the Prot method, is also given.

1955 ◽  
Vol 1 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Howard S Friedman ◽  
Martin A Rubin

Abstract 1. The Schwartzenbach method has been adapted for the simultaneous determination of calcium and magnesium in serum and spinal fluid. The method appears to be adaptable to all body fluids, including thoracic and abdominal transudates and exudates. Its use in the clinical laboratory is recommended because of the great saving of time, particularly in the determination of magnesium. 2. A series of 100 pathologic cases of various clinical entities has been analyzed by the new method and checked with the standard methods. A calculation and statistical analysis has revealed the Mg/Ca molar ratio to be of possible clinical significance.


Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.


2018 ◽  
Vol 3 (2) ◽  
pp. 52-61
Author(s):  
Dzikra Arwie ◽  
Islawati

Leukocytes or white blood cells have a characteristic characteristic of different cells. Determination of the impression of the number of leukocytes is determined in the number of cells in the field of view. While the number of viewable field cells expressed is still quite varied. The purpose of this study was to determine the number of leukocytes in the field of view and expressed the impression of a sufficient amount. This research was conducted at the Laboratory of Health Analyst Department Panrita Husada Bulukumba on 9 April 2017 to 14 July 2017. This type of research is a laboratory observation that aims to determine the criteria for assessing the impression of the number of leukocytes on a peripheral blood smear. Data analysis using statistical analysis is the average and standard deviations to determine the impression of the number of leukocytes and use 3 inspection zones. The results of this study obtained results in zone IV the number of leukocyte impressions said to be sufficient was 7-10, in zone V the number of leukocyte impressions said to be sufficient was 4-9, and in zone VI the number of leukocyte impressions said to be sufficient was 3-8.  


1977 ◽  
Vol 12 (1) ◽  
pp. 27-50 ◽  
Author(s):  
L.A. Behie ◽  
J.E. Zajic ◽  
D. Berk ◽  
R.J.P. Brouzes ◽  
V.A. Naish

Abstract Although Daphnia magna have been widely used in the determination of the toxicity of various substances, there are no reports in the literature that describe a rigorous bioassay method using this organism as a test species. The test described herein involves the standariza-tion of various important aspects of the method such as the age of the test organisms, and the dilution water used for the preparation of the various toxicant concentrations. Also described is a simple method for the statistical analysis of the results. The sensitivity of the proposed bioassay is demonstrated by determining the toxicity of various pulp and paper effluents. Finally, extensive bioassays were carried out simultaneously with rainbow trout and Daphnia magna indicating that Daphnia are as good a biological indicator of acute toxicity as fish.


1966 ◽  
Vol 49 (3) ◽  
pp. 511-515 ◽  
Author(s):  
R W Henningson

Abstract Bath level, sample temperature, rate of stirring, degree of supercooling, sample size, sample isolation, and refreezing of the sample were the variables in the thermistor cryoscopic method for the determination of the freezing point value of milk chosen for study. Freezing point values were determined for two samples of milk and two secondary salt standards utilizing eight combinations of the seven variables in two test patterns. The freezing point value of the salt standards ranged from –0.413 to –0.433°C and from –0.431 to –0.642°C. The freezing point values of the milk samples ranged from –0.502 to –0.544°C and from –0.518 to –0.550°C. Statistical analysis of the data showed that sample isolation was a poor procedure and that other variables produced changes in the freezing point value ranging from 0.001 to 0.011°C. It is recommended that specific directions be instituted for the thermistor cryoscopic method, 15.040–15.041, and that the method be subjected to a collaborative study.


2011 ◽  
Vol 197-198 ◽  
pp. 1658-1661
Author(s):  
Ying Xiong ◽  
Han Ying Zheng

Fatigue tests are carried out for 16MnR welded joint under constant strain control. Test results reveal that 16MnR weld metal exhibits characteristic of cyclic softening and non-masing obviously. The strain–life curve can be best described by the three-parameter equation. It shows the fatigue endurance limit in the heat-affecting zone (HAZ) of welded joint is lower than that in the weld metal.


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