scholarly journals A MATHEMATICAL MODEL OF TRAIN CONTINUOUS MOTION UPHILL

Transport ◽  
2008 ◽  
Vol 23 (2) ◽  
pp. 135-137 ◽  
Author(s):  
Gintautas Bureika

The determination problem of adhesion coefficient of locomotives’ wheels with rails is described in this paper. The use of methods of mathematical statistics and theory of probability provides wider possibilities for determining the most acceptable (suitable) value of the adhesion coefficient. The random factors influencing on this value are analysed. The use of the adhesion coefficient values based on reliable research results could help maintain uninterrupted (continuous) traffic of heavy freight trains and increase not only the carrying capacity, but also the volume of the transported goods. The paper considers a mathematical model of steady traffic of heavy freight trains pulled by upgraded locomotives of the series 2M62M on railway line with a gradient. The research results show that the actual values of the adhesion coefficient and the total resistance are distributed according to the normal distribution law. A mode of locomotive motion largely depends on the relationship between the total train's running resistance and locomotive tractive force. Finally, basic conclusions are given.

2019 ◽  
Vol 1 (2) ◽  
pp. 96
Author(s):  
Ana Cecilia De Paz Lazaro ◽  
Jessica Luz Palomino Collantes

The objective of the research is to determine the relationship between academic motivation and the professional skills development in the specialty of Social Sciences and Tourism. The study is quantitative and the design is non-experimental correlational translational. The results indicate that there is a high level relationship (0.914) between the independent academic motivation variable and the professional competences development in the Specialty of Social Sciences and Tourism. In conclusion, motivation is directly related to the professional skills development in the specialty of Social Sciences and Tourism. The research results conclude that there is a high relationship between the variables.


2020 ◽  
Vol 3 (1) ◽  

The aim of this study is to investigate the relationship between extrinsic and intrinsic reward on retention among Gen Y employees in Malaysian manufacturing companies. The data was collected from 113 respondents worked in manufacturing companies located in Seri Kembangan, Selangor using questionnaires. Multiple regression analysis was conducted to test the hypotheses. The results showed both extrinsic and intrinsic reward are the factors influencing retaining Gen Y in manufacturing companies. The discussion on the analysis, limitation of the study, recommendation for future research and conclusion were discussed at the end of this study. In a nutshell, it was proven extrinsic reward and intrinsic reward has contributed to the retention of Gen Y employees.


1991 ◽  
Vol 24 (5) ◽  
pp. 85-96 ◽  
Author(s):  
Qingliang Zhao ◽  
Zijie Zhang

By means of simulated tests of a laboratory–scale oxidation pond model, the relationship between BOD5 and temperature fluctuation was researched. Mathematical modelling for the pond's performance and K1determination were systematically described. The calculation of T–K1–CeCe/Ci) was complex but the problem was solved by utilizing computer technique in the paper, and the mathematical model which could best simulate experiment data was developed. On the basis of experiment results,the concept of plug–ratio–coefficient is also presented. Finally the optimum model recommended here was verified with the field–scale pond data.


2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2972
Author(s):  
Zhili Zuo ◽  
Jinhua Cheng ◽  
Haixiang Guo ◽  
Yonglin Li

Based on resource carrying capacity, this study used the revised theory of relative resource carrying capacity (RRCC) and introduced an innovative concept of relative fossil energy carrying capacity (RFECC), which evaluates the degree of fossil energy sustainability based on the relationship between economy, population, and environment. This study took China and the United States as the study objects, took the whole country as the reference area, and calculated the RFECC of population, economic, and environmental resources from 2000 to 2018. Therefore, based on the comparative analysis, the following conclusions were drawn: (i) there is a big difference in the RFECC between China and the United States, which is manifested in the inverted U-shaped trend in China and the U-shaped trend in the United States; (ii) the relative fossil energy carrying states in China and the United States are different, mainly reflected in the economy and environment; (iii) the gap in RFECC between China and the United States has gradually widened; in general, China’s economic RFECC is better than that of the United States, while environmental RFECC and population RFECC in the United States is better than that of China; and (iv) coal and oil should be used as a breakthrough point for the sustainable fossil energy and sustainable development for China and the United States, respectively.


2010 ◽  
Vol 26-28 ◽  
pp. 862-869
Author(s):  
Tao Peng ◽  
Zhi Peng Li ◽  
Chang Shu Zhan ◽  
Xiang Luo ◽  
Qian Wang

Through analyzing the process of brake, a dynamic model of automobile and a model of the relationship between braking distance and adhesion coefficient were formed; also a simulation calculating model of braking distance was established with the use of Matlab. Finally, a research was done toward the braking distance of a type of a car running on a road after using snow-melting agent. On one hand, with the application of the simulation model which has been established, calculations have been done to the braking distance of Bora vehicles running on roads after using deicing salt; on the other hand, by experiments, Bora vehicles’ braking distance and maximum braking deceleration under the same road condition were measured, meanwhile, the established simulation model was verified.


Author(s):  
S. Mendell ◽  
E. C. Bourlas ◽  
M. Z. DeBardeleben

AbstractThis paper comprises a review of the published literature (1936-1979) dealing with the relationship between the chemical constituents of tobacco and smoke and tobacco and smoke quality. Various components thought to be influential in determining quality are identified; conclusions of researchers regarding the effects of these components are recorded and discussed. A summary table is presented which details the nature of the relationship between these constituents and tobacco quality.


2020 ◽  
Vol 76 (4) ◽  
pp. 18-23
Author(s):  
LARISA V. Burmistrova ◽  

The analysis of pragmatic characteristics of humorous aphorisms in the context of life space. Author's humorous aphorisms of famous writers, poets, historians of the 17th, 18th, 19th centuries and modern humorous aphorisms posted on the Internet; collection of sayings, quotes and aphorisms “Big Book of Wisdom” (edited by Yuri Lavrov). The relevance of the research is determined by the interest in comic universal expressions, network discourse, comical texts. The research results are applicable when compiling a study guide for students or can be used to compile a psychological portrait of the hero of the work. The aim of the present study is to investigate the pragmatic characteristics of humorous aphorisms. It is analyzed that humorous aphorisms of famous writers, poets, historians of the 17th, 18th, 19th centuries and modern humorous aphorisms affect the main aspects of life. Pragmatic characteristics of humorous aphorisms are analyzed. It was found that the humorous aphorisms most vividly reflect the relationship and love between a man and a woman, the intellect of a woman and a man, care of women, the image of a strong, ambitious man, relationships in marriage, feelings (love and happiness), positive attitude (purposefulness, necessity of education), negative attitude (duplicity, laziness, stupidity, slight knowledge, exaggeration of material value), the contrary opinion of an optimist and a pessimist.


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