نشریه صنعت لاستیک ایران
پیاپی 93 (بهار 1398)

Determining the number of staffs is one of the most important issues of each manufacturing system, while the stopwatch technique is one of the most applicable time measuring methods in this area. In the stopwatch, one of the most useful ways for determining the performance rate of an operator is the Westinghouse approach. In the stopwatch method, tasks are broken into their elements, and the numbers of observations are calculated, then each task element will be time measured. Then the normal and standard time will be calculated. This study aims to measure the operator standard time for building a green tire for PCR in the Barez Industrial Group. However, since the performance rate of an operator plays a significant role in the measured time that is determined by the Westinghouse method, considering deterministic values for performance rate of each task will result in computational errors. Hence, this research uses fuzzy numbers for determining the performance rates of the Westinghouse method. For evaluating the proposed procedure, a real case from Barez Industrial Group that measures the standard and normal times of an operator of a radial tire manufacturing machine in the complex have been taken into account. The results show that considering uncertainty in the proposed method; causes finding more reliable and reasonable time measuring, compared with considering the ordinary Westinghouse method.

The use of Nano materials, such as Nano clay, is one of the most effective methods for improving the properties of polypropylene )PP(-Ethylene Propylene Diene Monomer )EPDM( composite. In this study, after the introduction of PP, EPDM, PP/EPDM and PP/ EPDM/Nano clay )PEN( Nano composite, the results of studies on PEN Nano composites were reviewed including of the preparation methods, the effect of application of various Nano clay loads on the mechanical, electrical, gas permeability properties and microstructure of the PEN Nano composite prepared by the twin screw extruder, the microstructure evolution of the PEN Nano composite during mixing in the twin screw extruder, and finally the deformation of the PEN Nano composite by applying compressive and shear force. Based on the results, the tensile strength of PEN Nanocomposites containing up to 5% by weight of Nano clay improved compared to the pure compound, due to changes in the interfaces properties, and the restriction of the movement and displacement of polymeric chains by the Nano clay particles. Applying of 5% Nano clay particles reduced the permeability to Oxygen by 6%, the electrical volume resistivity up to 70% and the dielectric constant by 6% and also increased glass transition temperature and flame resistance by up to 100 °C. in general, mechanical and electrical properties of PEN Nano composite depend on the degree of Nano clay layers dispersion in the polymer matrix. The best way to prepare Nano composite is to use a twin screw extruder, so that all the components are extruded simultaneously.

Competitiveness is one of the most important business concerns and activities in a dynamic and competitive environment today. The competitiveness of economies depends on the competitiveness of their companies. The main objective of this research is to identify and prioritize the effective factors on the competitiveness of the rubber industry. The present research is exploratory from the point of view of orientation, applied and from the target dimension. In this study, the factors influencing the competitiveness of the rubber industry were extracted using a background review and interview with experts. The statistical population of this study is the experts in the rubber industry. 15 experts were selected using available judgment sampling. The stages of this research are: extracting effective factors on the competitiveness of the rubber industry by employing interviews and reviewing the background, screening the research factors using binomial test, prioritizing research criteria with DEMATEL and EDAS techniques. Based on the results of the research, the order of priority of the research factors is the necessary industrial infrastructure, productivity, product quality, tax support, banking and customs.

The organization's performance is influenced by various factors that play a significant role in achieving the goals set. Human resources in the organization as an asset and the type of interactions within and outside the organization are among the factors that can predict organizational performance outcomes. Accordingly, organizations need to pay attention to their intellectual capital and provide an appropriate context for improving their work processes, in order to increase the efficiency of employees and their levels of performance on an ongoing basis. Additionally, the type of communications and communication in the business domain, as well as the lack of sufficient information for decision makers in the organization relative to market changes, can play a decisive role in the organization's work processes. The purpose of this study is to investigate the effect of components of intellectual capital in the form of organizational, human and customer capital on the overall performance of the organization in terms of market and organization performance considering the role of social capital, business links and environmental uncertainty.

This research was conducted to investigate the effect of ethical marketing and trust on purchasing customer behavior (studied by customers of Artavil Tire Ardabil Factory). The research method was descriptive, survey type. The statistical population consisted of customers of Artavil Tier Factory in Ardabil. Of these, 95 people were selected using simple random sampling method. The required information was collected through ethical marketing questionnaires, trustworthiness questionnaire, and shopping motility questionnaire. The validity of the questionnaires was confirmed by experts and researchers and their reliability coefficients were 0.84, 0.78 and 0.81 were obtained. Data were analyzed using descriptive statistics (frequency tables, mean, and standard deviations) and inferential methods (Pearson correlation coefficient and multivariate regression test). Based on the results of this study, there is a positive and positive relationship between ethical marketing and trust and customers 'behavior in Artavil Tire Company in Ardabil. Also, ethical marketing and trust are influential on Artavil Tire Factory customers' behavior in Ardabil.