scholarly journals Mathematical Model of New Type of Train Buffer Made of Polymer Absorber—Determination of Dynamic Impact Curve for Different Temperatures

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 47
Author(s):  
Hristijan Mickoski ◽  
Ivan Mickoski ◽  
Marjan Djidrov ◽  
Filip Zdraveski
Keyword(s):  
Mathematical Model ◽  
Influential Factors ◽  
Dynamic Impact ◽  
Factors Affecting ◽  
Impact Speed ◽  
Environment Temperature ◽  
Different Temperatures ◽  
New Type ◽  
The Impact

Previous experimental knowledge has confirmed that one of the most influential factors affecting the performance of polymer friction absorbers embedded in buffer housing as part of the buffer and chain coupler is the temperature. This paper defines a mathematical model of a friction-type polymer absorber, PMKP-110. The presented mathematical model specifically includes the influence of the environment temperature on the dynamic impact curve for −60 °C and 15 °C. The dependence between the initial pre-tension of the buffer and the ambient temperature is calculated. The model involves an equation of motion for moving parts of the absorber, and the solution of the differential equation is achieved in Matlab. Results are given as diagrams of the impact deformation and impact speed of the polymer block, with assumed zero initial impact speed. The model can be used to analyze the action of the longitudinal forces that occur during transient conditions of the movement of the carriages.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

scholarly journals A Control Based Mathematical Model for the Evaluation of Intervention Lines in COVID-19 Epidemic Spread: The Italian Case Study

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 890
Author(s):  
Paolo Di Giamberardino ◽  
Rita Caldarella ◽  
Daniela Iacoviello
Keyword(s):  
Mathematical Model ◽  
Equilibrium Points ◽  
Italian Case ◽  
Control Actions ◽  
Containment Measures ◽  
Asymptomatic Subjects ◽  
The Impact

This paper addresses the problem of describing the spread of COVID-19 by a mathematical model introducing all the possible control actions as prevention (informative campaign, use of masks, social distancing, vaccination) and medication. The model adopted is similar to SEIQR, with the infected patients split into groups of asymptomatic subjects and isolated ones. This distinction is particularly important in the current pandemic, due to the fundamental the role of asymptomatic subjects in the virus diffusion. The influence of the control actions is considered in analysing the model, from the calculus of the equilibrium points to the determination of the reproduction number. This choice is motivated by the fact that the available organised data have been collected since from the end of February 2020, and almost simultaneously containment measures, increasing in typology and effectiveness, have been applied. The characteristics of COVID-19, not fully understood yet, suggest an asymmetric diffusion among countries and among categories of subjects. Referring to the Italian situation, the containment measures, as applied by the population, have been identified, showing their relation with the government's decisions; this allows the study of possible scenarios, comparing the impact of different possible choices.

scholarly journals The Hydrophobic Effect in the Adsorption Process of Alkyltrimethylammonium Bromides on to Activated Carbon

1998 ◽  
Vol 16 (7) ◽  
pp. 557-564 ◽  
Author(s):  
Jinben Wang ◽  
Yao Lu ◽  
Buxing Han ◽  
Ming Dai ◽  
Haike Yan ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Process ◽  
Hydrophobic Effect ◽  
Carbon Surface ◽  
Thermodynamic Quantities ◽  
Factors Affecting ◽  
Alkyltrimethylammonium Bromides ◽  
Different Temperatures ◽  
Surface Measurements

This paper describes the hydrophobic effect in the process of adsorption of alkyltrimethylammonium bromides from aqueous solution on to an activated carbon surface. Measurements of the adsorption isotherms of a series of alkyltrimethylammonium bromides with different hydrocarbon tail lengths at the activated carbon surface were carried out. In order to investigate the temperature dependence of the adsorption process, the determination of the adsorption of cetyltrimethylammonium bromide (CTAB) was undertaken at different temperatures in the range 20–60°C. From the experimental results obtained, the relevant thermodynamic quantities have been calculated. The role played by the hydrophobic effect in the adsorption process of cationic surfactants on to activated carbon and the factors affecting the adsorption mechanism were discussed.

scholarly journals Effects Of The Combined Heat And Cryogenic Treatment On The Stability Of Austenite In A High Co-Ni Steel

2015 ◽  
Vol 60 (3) ◽  
pp. 2131-2137 ◽  
Author(s):  
M. Gruber ◽  
S. Ploberger ◽  
G. Ressel ◽  
M. Wiessner ◽  
M. Hausbauer ◽  
...  
Keyword(s):  
Phase Distribution ◽  
Cryogenic Treatment ◽  
Tempering Temperature ◽  
Factors Affecting ◽  
Transmission Electron ◽  
Reverted Austenite ◽  
Before And After ◽  
Different Temperatures ◽  
The Stability ◽  
The Impact

Abstract The stability of austenite is one of the most dominant factors affecting the toughness properties of high Co-Ni steels such as Aermet 100 and AF1410. Thus, the aim of this work was to get a deeper understanding on the impact of combined heat and cryogenic treatment on the stability of retained and reverted austenite. In order to characterize the evolution of the phase fraction of austenite during tempering at different temperatures and times, X-ray diffraction analyses were carried out. The stability of austenite, which was formed during tempering, was analyzed with dilatometric investigations by studying the transformation behavior of the austenite during cooling from tempering temperature down to −100°C. Additionally, transmission electron microscopy investigations were performed to characterize the chemical composition and phase distribution of austenite and martensite before and after tempering.

scholarly journals Mathematical model for determining the limit load capacity of an energy-intensive profile of class 4

2018 ◽  
Vol 19 (9) ◽  
pp. 133-136
Author(s):  
Dominik Gałdyński
Keyword(s):  
Mathematical Model ◽  
Cross Section ◽  
Load Capacity ◽  
Limit Load ◽  
Stress And Strain ◽  
Mathematical Apparatus ◽  
Load Bearing Capacity ◽  
Automotive Body ◽  
The Impact

The article discusses the process of stress and strain changes for an energy-intensive profile with a square cross-section as a result of axial compression, expressed using a mathematical apparatus that allows determination of the load-bearing capacity of such a profile, the use of which in the form of stringers is found in modern automotive body constructions . Elements, such as the so-called a zone of controlled crumpling, taking over part of the impact energy, at the same time being responsible for the progressive nature of the deformation of this area.

scholarly journals Determination of the Course of COVID-19 Pandemic Using Modified Logistic Modeling

2021 ◽  
pp. 17-26
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mortality Rate ◽  
Tract Infection ◽  
Large Population ◽  
High Rate ◽  
The World ◽  
New Type ◽  
Short Time

Introduction: COVID-19 appeared in China at the end of 2019. It then spread all over the world very quickly. The new type of corona virus COVID-19, which causes respiratory tract infection, is destructive with its high rate of transmission and mortality rate. Materials and Methods: In this study, determining the course of the COVID-19 pandemic for next 4 months in Afghanistan with the help of a specially modified mathematical modeling is intended to reveal. Results: results of our study show that the COVID-19 pandemic can affect a large population in Afghanistan in a short time. However, it is possible to reduce the number of cases and deaths very effectively with easy measures. Keywords: COVID-19, precautions, pandemic, logistic mathematical model, Afghanistan.

scholarly journals Investigating the reasons for failures and delays in R&D projects with the project management approach

2020 ◽  
Vol 1 (4) ◽  
pp. 319-334
Author(s):  
Saeed Ghorbani ◽  
◽  
Shayan Naghdi Khanachah ◽  
Keyword(s):  
Organizational Factors ◽  
Research Area ◽  
Influential Factors ◽  
Management Approach ◽  
Research Projects ◽  
Organizational Productivity ◽  
Factors Affecting ◽  
Effective Factors ◽  
The Subject ◽  
The Impact

Purpose: This study aimed to identify and investigate the reasons for failures and delays in R&D projects with an organizational productivity approach. Research methodology: In order to identify the most influential factors in the research area, a questionnaire with a Likert spectrum of five options was designed and distributed among the stakeholders of research projects. The questionnaire results were analyzed and 10 more effective factors were identified and solutions were used to improve the situation. Result: In the present study, after reviewing the background of the subject and reviewing previous studies, 149 factors affecting the failure and delay of projects were identified and after aggregating and summarizing the factors, a model was designed to classify the causes of delay in which 55 effective factors in two general categories. Intra-organizational and extra-organizational factors were examined. Limitations: This research only described Research-oriented organizations. Contribution: According to the analysis results regarding the more effective causes, problems and challenges related to each of the factors were studied and to reduce the impact of existing factors, various solutions and suggestions in the field of research variables using Expert opinion was provided.

Fatigue Life of Aircraft Tires

1988 ◽  
Vol 16 (4) ◽  
pp. 208-222 ◽  
Author(s):  
S. N. Bobo
Keyword(s):  
Mathematical Model ◽  
Fatigue Life ◽  
Experimental Confirmation ◽  
Operating Environment ◽  
Calculated Temperature ◽  
Lateral Forces ◽  
Heating Model ◽  
The Impact ◽  
The Mathematical Model

Abstract A study was conducted to determine if a safe upper service limit can be set for aircraft tires, based on an operation profile of the aircraft using the tires. The study consisted of three parts: development of a tire heating model, experimental confirmation, and determination of tire degradation as a function of time at temperature. Three operational profiles were identified: long, intermediate, and short haul; these stressed tires in different ways. The mathematical model, which calculated temperature as a function of time for various axial and lateral forces at different speeds, was developed and confirmed by experiment. It predicted the time at temperature of the hottest part of a tire that is exposed to the operating environment of the profiles. The impact of heating was found from a determination of ply adhesion as a function of time at temperature. The end of tire life was judged to occur when ply adhesion was degraded by 50%.

scholarly journals Determination of Oleanolic and Ursolic Acids in Sambuci flos Using HPLC with a New Reversed-phase Column Packed with Naphthalene Bounded Silica

2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Michal Gleńsk ◽  
Maciej Włodarczyk
Keyword(s):  
Oleanolic Acid ◽  
Pharmacological Action ◽  
Reversed Phase ◽  
Hplc Method ◽  
Biologically Active ◽  
Factors Affecting ◽  
New Type ◽  
Phase Column ◽  
Reversed Phase Column

Elder flowers have traditionally been used for their anti-inflammatory properties. However little is known about triterpenoid components in this Pharmacopoeial herbal drug. Herein, we report the quantification of ursolic and oleanolic acid in Sambuci flos by HPLC method. These biologically active triterpenoids were effectively separated and quantified using the elaborated HPLC chromatographic method with a naphthalene bounded silica reversed phase column. In this study, a very simple mobile phase for HPLC was developed to simultaneously determine both acids and the factors affecting separation were also discussed. The average content of oleanolic acid and ursolic acid in the elder flowers determined by proposed method was 2.06 mg/g and 11.56 mg/g respectively. This study showed both successful applications of the new type of reversed phase column and important contribution of mentioned triterpenoids to elder flower composition presumably resulting in its pharmacological action.

Study on the Determination of the Separated Layer Water Injection Based on the Grey Synthetic Degree

2014 ◽  
Vol 644-650 ◽  
pp. 2227-2230
Author(s):  
Yao Lin ◽  
Chun Lin Liu ◽  
Hong Jun Yin ◽  
Xiao Yan Xu ◽  
Yang Wang
Keyword(s):  
Influence Factor ◽  
Water Injection ◽  
Influential Factors ◽  
Oil Field ◽  
Water Flooding ◽  
High Yield ◽  
Grey Correlation Analysis ◽  
Correlation Analysis Method ◽  
The Impact

The determination of the rational layered water injection intensity is the basis to stable oil production and high-yield in oil field. This article analyzes the various influential factors of the separated layer water injection intensity, using grey synthetic degree to determine the dominant influential factors. The weight value is obtained by normalization, each influence factor is quantization. Using grey correlation analysis method to determine the plane dividing coefficient and the vertical dividing coefficient, a reasonable stratified water injection intensity formula is got. This method considers the impact of these factors which consist of permeability, the measure transformation coefficient, perforation thickness, injector producer distance, location coefficient and the number of injector and producer. The problem which the contradiction exists in the same layer or between the layer and layer is obvious in the D block through combining with the current water injection development, reasonable dividing coefficient of block is established, a reasonable stratified water injection intensity formula is got, making well block reasonable injection and increasing adjustment effect of water flooding.

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