نشریه صنعت لاستیک ایران
پیاپی 102 (تابستان 1400)

In the present research work, a detailed comparative study was accomplished on more recently developed gas mask products to evaluate several different types of elastomers, as major design variants in required rubber compounding. Through a systematic definition of evaluation criteria (including eight technical criteria, two economical and three satisfactory criteria), radar diagrams and evaluation matrix were formed. Meanwhile, based on the manufacturer's knowledge and experience, the importance of the technical, economical and satisfactory criteria were found as 60, 30 and 10%, respectively. It was found that all of the investigated elastomers have the same technical potential for gas mask production. However, taking into account the techno-economical considerations simultaneously for gas mask production in Iran, results revealed that the desirability of these elastomers follows the trend of polyisoprene (NR)> polychloroprene (CR)> ethylene-propylene-diene (EPDM)> butyl rubbers (IIR)> silicone rubber (Q)> nitrile-butadiene rubber (NBR).

Over the past few years, vehicle safety technology has evolved drastically. Tires are one of the core components of the vehicle that determine performance and play a major role in its safety. They carry the vehicle load and are the only contact with the road surface. As a result, tires contain useful information about tire temperature and pressure, wheel load, tire wear, and changing road conditions. Smart tires have the potential to be widely used to enhance the safety of road transportation systems by providing effective parameters on the performance and safety of tires. On the other hand, the rise of global security and the emergence of concepts such as the Internet of Things (IoT) have driven tire industries to produce smart tires. In this paper, the design and manufacturing processes of the smart tire in Barez Industrial Group is explained. This new tire measures pressure, temperature, and mileage of the tire constantly. The Barez smart tire has three main components including the sensor package installed inside the tire, the control unit placed inside the vehicle cabin, and a smartphone application, which is the communication route between the tire and the driver.

Rolling resistance sits at the core of tyre development goals because of its considerable ect on the car’s fuel economy. Rolling resistance depends many factors in a tire. The tread of tire have the most contributions in energy loss due to deformations caused by bending, pressure and shearing. Due to the long time of problem solving and the heterogeneity of numerical solutions as well as the inadequate understanding of the effect of different parameters on the rolling resistance, analytical solutions are used. . In this paper, by using the analytical method, the effect of various factors such as internal pressure, Young's modulus, tire load, belt radius, tread width, tread thickness, contact surface rate (csr) and sinδ on rolling resistance are investigated. . Finally, by using the Isight Design Gateway optimizer software, the optimal value of the tire rolling resistance in a TBR tire is obtained.

One of the reasons for the short life time of heavy tires is wear, caused in the tire by various factors. Heavy vehicle tires are more affected by abrasion and wear for various reasons, such as high weight, movement on rocky ground, heavy loads exerted on the vehicle, and as a result, have a relatively shorter life time. Although in recent studies, research has been conducted on abrasion due to several cases, in this article, the effective factors on abrasion of heavy vehicle tires are studied according to their special working conditions. New methods of wear detection and control of the wear process are discussed. This study will help identify the key causes of tire wear, providing suitable working environment for tires, distinguishing more sensitive parts of the tire, and recognizing better operating conditions. Finally, this paper introducer wear detection technologies using sound waves and acoustics and by means of neural network and wear detection sensors, and the effect of tire wear on car fuel consumption is investigated and a new technology of selfrepairing tires is introduced.

New digital technologies are on their way to disrupt nearly all areas of what we call ‘traditional business processes. Supply chain management (SCM) as a key business priority of almost every manufacturing company finds itself in the center of this upcoming digital era .Suppliers, partners, companies and dealers in supply chains do use, generate and share information with others. These associations lead to a multitude of challenges and opportunities within the supply chains. Digital Supply Chain (DSC) is a smart, value-driven, efficient process to generate new forms of revenue and business value for organizations and to leverage new approaches with novel technological and analytical methods. Digital Supply Chain (DSC) t is about the way how supply chain processes are managed with a wide variety of innovative technologies. purpose of this paper is to propose a framework for digital supply chain (DSC).This paper uses a literature approach, based on the main Industry 4.0 elements, Digital Supply Chain Dimensions and the emerging literature concerning digital supply chain (DSC). to build an integrative framework to digital supply chain (DSC). In fact, this paper presents a development framework for the digital supply chain that illustrates the importance of the digital supply chain. The results of this digital supply chain research are relevant to answer questions such as the current state of the digital supply chain in academic and industrial studies as well as future developments in digital supply chain management.

The main purpose of this study was to investigate the relationship between transformational leadership, project participation, project abandonment and employee perceptions of employer safety commitments. This study is applied in terms of purpose. Also, the present research is in the nature of descriptive correlational research in terms of nature and method. The statistical population in this study is managers and staff active in oil and gas projects. Accordingly, random sampling was used in this study. The sample size of this study is 384 according to Morgan table. The data collection tools used in this study included Ding et al (2017) and Mullen et al (2017) questionnaires. The items in these questionnaires were designed based on a five-point Likert scale. Confirmatory factor analysis was used to analyze the findings of the present study. The findings of the study showed that from the viewpoint of the respondents, transformational leadership had a significant impact on project participation; desire to quit the project and employee perception of employer safety commitment. In fact, this research shows that changes in project participation levels, project abandonment, and employee perceptions of employer safety commitment can be explained and interpreted by transformational leadership and leadership styles, and organization managers should pay more attention to use and Implement transformational leadership style.

Various researchers believe that emotion is a key variable in understanding customer experience and subsequent behavior. The purpose of the present study was to investigate the impact of social environment (including emotions presented by employees, customer mood), physical environment (environmental factors and design factors), and quality of service on positive and negative emotions of customers and then the effect of customer emotions on post-purchase behaviors ( Intent to repurchase, desire to change, desire to sue).

The research method is descriptive-quantitative in terms of purpose, application and nature. The statistical population of the present study is a set of customers of 5 star hotels in Tehran. Data collection tool was a questionnaire with 350 questionnaires.

The results obtained using Structural Equation Technique and Emus software showed that 4 out of 22 hypotheses were rejected.

The results showed that factors of social environment and quality of service had positive effect on customers 'positive emotions and negative effects on customers' negative emotions. The results also showed that positive emotion had a positive and significant effect on customer repurchase intention. The study found that negative emotions had a positive effect on willingness to complain and willingness to change.

Nowadays, the issue of human resource management has become important and one of the indicators for measuring the superiority of organizations over each other is the employees working in those organizations. Therefore, issues related to human resources, including job security of employees are considered important. Perception of high job security has a significant effect on retired intentions, job leaving intention, job satisfaction, organizational citizenship behavior, organizational commitment, political behavior, and increasing organizational productivity. Therefore, organizations are trying to achieve the necessary efficiency by increasing job security and meeting the needs of employees. This is important in production cooperatives where employees face almost low job security. Therefore, the purpose of this study is to investigate the impact of job security on organizational commitment in production cooperatives in Ardabil province. The purpose of this study is descriptive and correlational and the size of the statistical population is 305 people, of which 169 people were selected and a questionnaire was distributed among them (due to lack of access to the statistical population, 305 people were selected for the study). Correlation method was used to test the research hypotheses. The results showed that job security directly affects organizational commitment in jobs such as cooperatives. This study also correlates the dimensions of job security and organizational commitment, including; Focus on job reduction in job transfer, job selection, job satisfaction, economic satisfaction, emotional work environment, sense of calm, organizational commitment and organizational defense were confirmed, among which the emotional dimension of the work environment with a correlation coefficient of / 78. 0 has the greatest impact on the commitment of the employees of production cooperatives.