scholarly journals Stochastic load generated by the beam irregularities

2018 ◽  
Vol 211 ◽  
pp. 11007 ◽  
Author(s):  
Piotr Koziol ◽  
Dariusz Kudla ◽  
Cristinel Mares

The problem investigated in this paper comes from railway engineering. It is known that geometrical irregularities of the rail head rolling surface produce additional force when the train runs on track. This force can be quite significant and should not be neglected in the analysis, especially when one deals with high-speed railways. In this paper, an analytical method of modelling of such irregularities is presented. The detailed description of this method is associated with its practical application to the analysis of the rail track dynamic response to moving train. However, stochastic analysis of the presented model is omitted in this paper and left for further work. This should include a number of realisations along with statistical analysis of results, or description of the rail track subjected to moving train in terms of stochastic differential equations, which is the main direction of the authors future investigations.

1988 ◽  
Vol 25 (04) ◽  
pp. 239-252
Author(s):  
G. Robed Lamb

Even though in 1987 there were only a dozen SWATH (smali-waterplane-area twin-hull) craft and ships afloat around the world, word of their markedly superior seakeeping performance is spreading rapidly. The number of SWATH vessels is likely to double within five years. As in many other areas of technology, the United States and Japan are the acknowledged leaders in the development and practical application of the SWATH concept. This paper reviews the characteristics of existing SWATH craft and ships from the standpoint of the stated seakeeping objective. Hull form differences between four SWATH craft and ships, including the Navy's SSP Kairnalino, are analyzed and interpreted. Important considerations for the early-stage design of a SWATH ship are discussed. Differences in the range of feasible hull form geometries for coastal areas and unrestricted ocean operations, and for low-speed versus moderately high-speed applications, are pointed out.


2008 ◽  
Vol 3 (3) ◽  
pp. 3
Author(s):  
Robert A. Wright

Objective – The aim of this article is to present evidence based methods for the selection of chemistry monographs, particularly for librarians lacking a background in chemistry. These methods will be described in detail, their practical application illustrated, and their efficacy tested by analyzing circulation data. Methods – Two hundred and ninety-five chemistry monographs were selected between 2005 and 2007 using rigorously-applied evidence based methods involving the Library's integrated library system (ILS), Google, and SciFinder Scholar. The average circulation rate of this group of monographs was compared to the average circulation rate of 254 chemistry monographs selected between 2002 and 2004 when the methods were not used or were in an incomplete state of development. Results – Circulations/month were on average 9% greater in the cohort of monographs selected with the rigorously-applied evidence based methods. Further statistical analysis, however, finds that this result can not be attributed to the different application of these methods. Conclusion – The methods discussed in this article appear to provide an evidence base for the selection of chemistry monographs, but their application does not change circulation rates in a statistically significant way. Further research is needed to determine if this lack of statistical significance is real or a product of the organic development and application of these methods over time, making definitive comparisons difficult.


2019 ◽  
Vol 21 (6) ◽  
pp. 1577-1592 ◽  
Author(s):  
Zhongbai Jiang ◽  
Changqiao Xu ◽  
Jianfeng Guan ◽  
Yang Liu ◽  
Gabriel-Miro Muntean

Author(s):  
Muataz Al Hazza ◽  
Khadijah Muhammad

High speed machining has many advantages in reducing time to the market by increasing the material removal rate. However, final surface quality is one of the main challenges for manufacturers in high speed machining due to the increasing of flank wear rate. In high speed machining, the cutting zone is under high pressure associated with high temperature that lead to increasing of the flank wear rate in which affect the final quality of the machined surface. Therefore, one of the main concerns to the manufacturer is to predict the flank wear to estimate and predict the surface roughness as one of the main outputs of the machining processes. The aim of this study is to determine experimentally the optimum cutting parameters: depth of cut, cutting speed (Vc) and feed rate (f) that maintaining low flank wear (Vb). Taguchi method has been applied in this experiment. The Taguchi method has been universally used in engineering analysis.  JMP statistical analysis software is used to analyse statically the development of flank wear rate during high speed milling of hardened steel AISI D2 to 60 HRD. The experiment was conducted in the following boundaries: cutting speed 200-400 m/min, feed rate of 0.01-0.05 mm/tooth and depth of cut of 0.1-0.2 mm. Analysis of variance ANOVA was conducted as one of important tool for statistical analysis. The result showed that cutting speed is the most influential input factors with 70.04% contribution on flank wear.


2019 ◽  
Vol 72 (5) ◽  
pp. 988-992
Author(s):  
Olena P. Babkina ◽  
Volodymyr V. Zosimenko ◽  
Svitlana I. Danylchenko ◽  
Andriy A. Chernozub ◽  
Illia I. Vako ◽  
...  

Introduction: The article presents data from literary sources and a statistical analysis of our own research on the nature, mechanism and prescription of kidneys injury in case of mechanical trauma and the absence of alcohol intoxication. The aim: To study the dynamics of changes in the histological parameters of the kidneys injured tissues in case of mechanical trauma depending on the prescription of injury. Materials and methods: The material of the study was the kidneys tissue of 48 males and females aged from 20-60 who died at known and unknown time in the presence and absence of alcohol in the blood. We used histological, histochemical methods, and carried out the analysis of results. Results: The obtained results showed that during the mechanical injury of kidneys there often developed a capsule and a parenchyma with hematoma in the area of injury. Our records showed that during the first 6 hours after injury, there appeared a hematoma in the center of the injury. Hemolysis of the erythrocyte particles was observed in the center of the hematoma. There were also isolated leukocytes and fibrin tissues closer to the edge of the hematoma. Conclusions: The obtained results indicate that there are several histological changes in the damaged kidneys tissues area which directly depend on the time which passed from the moment of injury.


2012 ◽  
Vol 253-255 ◽  
pp. 1273-1277
Author(s):  
Xue Dong Du ◽  
Na Ren

The research of high-speed railway running economic benefit is important to timely know well the train operation state for the railway administration. A prediction model of high-speed railway running economic benefit is proposed in this article based on Gray model. The Gray model is a good example to make accurate prediction of the development of matters. According to the data analysis of Beijing and Shanghai railway stations, we can know that the result of prediction model is accurate, so the prediction based on Gray model is scientific and reasonable in the practical application.


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