نشریه صنعت لاستیک ایران
پیاپی 105 (بهار 1401)

A rotated tire is affected by various forces and torques from the contact patch. On the other hand, the structure of the tire is very complex and tire is a complex combination. Each of these components can affect the forces and torques applied to the tire. These forces and torques also have a great effect on the handling of the car. In this paper, the apex height, the belt width, the belt angle and the capply type in a PCR tire are considered. The design of Experimental is based on Taguchi method which related to the apex height, the belt width, the belt angle and the capply type. Based on the design of experimental, 9 different tires have been made. The values of cornering stiffness obtained from the experimental and the effect of the mentioned factors on the cornering stiffness of the tire has been investigated.

In this study, the effect of different accelerators on curing characteristic and physical-mechanical properties of chloroprene rubber were investigated. In preparation of rubber compounds some accelerators such as CBS, MBTS, TMTD and sulfur in combination with ethylene thiourea (ETU) were used. The carbon black N550 was used as filler. The curing temperature and curing time were 150℃ and 30 minutes respectively and was constant for all compounds. The physical-mechanical properties of vulcanizates including hardness, modulus, tensile strength, elongation at break and tear strength were measured. The rheometer results showed that torque and scorch time were increased when CBS and sulfur were combined with ETU toward ETU alone system. The vulcanizates with TMTD and ETU had higher tensile strength, tear strength and modulus. Addition of sulfur in the presence of ETU curative could increase the mechanical properties such as hardness, elongation and modulus in comparison to ETU alone curing system.

The purpose of this study is to identify the factors that lead to the customer loyalty of Rubber Shareholder Customers. This study is an applied type of research due to the purpose, with a descriptive survey approach due to data. Statistical population of this research contains Iranian Capital Market investors and activists in the fall 1995. Sampling was done randomly by distributing a questionnaire consisting of 18 questions among 385 investors. For data analysis, multivariate regression analysis and Pearson correlation coefficient have been used. The results indicate that there is a positive and significant relationship between customer satisfaction, brand image and switching costs with customer loyalty. In addition, among the mentioned factors, customer satisfaction has the most impact in terms of customer loyalty. The results are corresponded with the findings of previous studies, in relation to customer loyalty of service industries. The managers of the stock brokerage companies can use these results in order to improve customer relations and increase their loyalty.

A modern tire combines up to 300 different chemical elements, including organic and inorganic, natural and synthetic. During production, there are various processes such as mixing, rolling and extrusion. Then, molding and vulcanization inside special molds brings the final shape of the rubber. Because the surface quality of the molds strongly affects the quality of the tire, mold cleaning is an essential aspect of all tire production and cleaning methods are constantly evolving. This research proposes a global evaluation of tire mold cleaning systems including unusual solutions such as multi-axial robots for laser or dry ice cleaning or ultrasonic cleaning that uses cavitation. Special attention has been paid to the use of spring vent in molds industrially and how they affect the quality development of final products.

Polymer composites have been widely welcomed by researchers due to their low weight, desirable mechanical properties, and various production methods than other types of composites. In this article, first, the activities and studies of researchers have been reviewed in the view point of make polymer composites with higher mechanical properties and how to measure important mechanical properties and related tests. In the other section, the types of reinforcements used in polymer-based composites are reviewed in terms of type (natural or synthetic), surface shape and morphology as well as their impact on mechanical properties. According to the results and studies, it was found that the strength of composite specimens made is directly related to the shape and amount of reinforcement used. Also, if the contact surface of the reinforcement with the polymer matrix is increased, the mechanical properties of the composite will increase. In this regard, two-dimensional nanoparticle and fiber reinforcements have a higher strength than composites containing particle reinforcements.

Insurance companies need information about the needs and wants of customers to attract and retain customers and improve their performance, and access to this information is possible through constant communication with them. Due to the expansion of the use of information technology in recent years, one of the most effective methods used to communicate with customers is the use of social networks and the implementation of electronic customer relationship management. The purpose of this study is to investigate the role of using social networks and electronic customer relationship management in improving marketing performance in insurance companies. The statistical population includes the managers and employees of these companies, which is a total of 280 people. A sample of 162 people was obtained based on Morgan table, and finally 155 questionnaires were collected. Structural equation model with LISREL software was used to analyze the data. The results show that the use of social networks and success in implementing e-customer relationship management has a positive effect on the marketing performance of insurance companies. The use of social networks also has a positive effect on the success of the implementation of electronic customer relationship management. Success in implementing e-customer relationship management has also played a mediating role in the relationship between the use of social media and the marketing performance of insurance companies.

In each country, according to the geographical location of that country, there are unique products that can be used in rubber compounds. The use of these materials in some cases can improve the mechanical properties of the rubber compound, reduce environmental risks and in some cases reduce costs. Therefore, knowing the properties and characteristics of these materials and also using the experiences of others in using them can be an effective help in choosing them as a component of the compound. In this research, based on the reported articles and studies, a number of materials that can be used as fillers are introduced and their effect on the mechanical properties of polymeric materials, especially rubber compounds is presented. Some of the introduced materials are available in our country and the study of the present article is useful for how to use them in polymer matrices. It is also expected that paying attention to this issue will be an incentive to find other materials that are native to our country and can be used in the rubber compound.role in the relationship between the use of social media and the marketing performance of insurance companies.

Junk energy is usually harmful, causing damage and reducing the useful life of systems. Therefore, this vibrations are required to be absorbed or controlled. One important factor in the study of dynamic systems is damping energy or loss of energy. Damping of energy is defined as the capability of a material in absorbing energy and converting it into heat. Damping in a system consists of two parts: structural damping and material damping. Structural damping depends on the geometrical properties of the structure and its components, and the material damping is due to internal friction and is dependent on the intrinsic properties of the material. In general, rubber is considered as the best energy absorption due to viscoelastic behavior. The characteristic which that separates the special behavior of rubbers to the energy absorption from other polymers is their amorphous structure (with microscopic free volume for mobility) and flexible chains. Internal friction between polymer chains is an important mechanism in damping of rubber material, depending on the flexibility of the chain and the free volume. In this study, the role of the nature of material in damping energy is investigated.