فهرست مطالب hirsa jouya ardekani

In this study, films consisting of TEMPO-oxidized cellulose nanofibers (TOCNF) prepared from eucalyptus and graphene oxide (GO) were prepared by casting-evaporation method. The morphological structure, thermal stability and mechanical properties of the nanocomposite films were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and tensile mechanical tests. The results obtained from the X-ray diffraction spectrum, FTIR spectrum and SEM observations revealed that TOCNF and graphene oxide were able to form nanocomposite films with homogeneous structure in low-weight percent of graphene oxide. Compared with films of Tempo-oxidized cellulose nanofibers (TOCNF/GO0%), the mean tensile strength of nanocomposite films consisted of 1.5 wt% of graphene oxide (TOCNF/GO1.5%) increased to 19%, which was not statistically significant. In addition, the mean tensile strength of nanocomposite films consisted of 3wt% of graphene oxide (TOCNF/GO3%) decreased to 14.5%, which was not statistically significant. The results of TGA showed that the thermal degradation temperature of TOCNF/GO0.5%, TOCNF/GO1.5% and TOCNF/GO3% nanocomposite films compared to the film of TOCNF/GO0% slightly changed towards lower temperatures.

Statistical process control and maintenance management are two key tools for controlling production processes. However, These two tools are traditionally separated (both in science and in business practice), their goals overlap a great deal. Their common goal is to achieve optimal product quality, little downtime and cost reduction by controlling variances in the process, that achieving these goals will increase the level of reliability of product quality. Using these two tools together can have better performance in terms of cost and quality for the organization; Therefore, in this research, an integrated model of statistical process control and maintenance management has been designed by considering the costs of two tools in Kish Wood Industries Company. The optimization criterion is to minimize the average total cost per unit time of these two systems. For this purpose, from MATLAB software and grid search approach to find the optimal values of sampling size (n), width of control limits (L), sampling interval (h) and number of sampling times during the planned maintenance (k) is used.The values of n, h, L and k for the laminating process were calculated as 5, 1, 2.9 and 30, respectively. The results of this optimization in the studied process show that the duration of the planned maintenance should be increased compared to the existing program, and this can be due to compensatory maintenance when the false alarm is out of control of the process.

In this research, application of statistical quality control process in Kishwood industrial company has been investigated. Statistical quality control process includes control charts and acceptance samplings. In this study, qualitative and quantitave characteristics of raw material and work in progress was investigated using standard tables and control charts ( U) were designed  for grooving, drilling, laminating and edge banding processes. In the raw material and work in progress, medium density fiberboard (16mm) lots, HPL veneer, purchased ABS stripe and the distance of the double hole from the edge of the piece in terms of quantative characteristic were investigated by MIL-STD-414 tables. In addition, purchased veneered particle board lot and the accuracy of the stripe in cabinet bottom parts in terms of qualitative characteristic were investigated by MIL-STD-105E tables. All the results were compatible with the acceptable standards of the company. Since lots data were located in the control limits, we can conclude that the whole process had been under control during the research time and can be used to control the future of the process. By calculating the process capability index (CP), it was found that grooving and drilling process have a very high capability, so the percentage of waste in these two processes is very low.