Centrifugal slurry pumps are being used in many mineral companies to transport mineral materials. These materials are mainly abrasive and the liner of these pumps are eroded during their working life. Zinc oxide (ZnO) are usually used for enforcing rubber material but, the ZnO is harmful to the environment. Nano ZnO (n-ZnO) particles seem to purvey higher activity. In this work, the inlet liner of a centrifugal slurry pump was fabricated with n-ZnO that decreases environmental concerns and improves its wear life. The composite of inlet liner is made of Natural rubber (NR) and Polybutadiene rubber (PBR). For determining the optimal dosage of n-ZnO within the composite, mechanical properties for rubber compounds comprising 1-2 unit(s) n-ZnO, were investigated comparing to those of the compound with 5 units conventional ZnO (c-ZnO). It was found that optimal amount of n-ZnO was 1 unit which it was enough to give equivalent or better mechanical properties compared to one containing a higher amount of, namely 5 units, c-ZnO in the composite. In addition, field-emission scanning electron microscopy (FESEM) photo showed that n-ZnO particles were homogeneously dispersed in the composite. Finally, two inlet liners were manufactured, one of them was with 1 unit of n-ZnO (n-liner) and the other one with 5 units of c-ZnO (c-liner). These two liners were used in service in a plant. The field study showed that the life of n-liner was 1/3 unit more than the life of c-liner and n-liner face has been worn less than c-liner one. Manuscript profile

In sensitive mechanisms, achieving the required accuracy of the final parts at the most suitable price is a complex process. The tolerance design process is essential in design and manufacturing to achieve a quality and low-cost product. Allocation of appropriate tolerances is always time-consuming and challenging, especially for complex products, as it involves many aspects of design, manufacturing, and quality issues. In this research, a program has been written in MATLAB, in which by only one geometry model, all possible interferences of assembled parts for all tolerances and nominal sizes in different production modes have been investigated. By using this program, it is possible to add or reduce applied tolerances to nominal sizes and check the interference of parts for all tolerances. Also, temperature effects must be considered when designing a product that operates in a wide temperature range. This approach could ensure that the values of the output parameters of the mechanism remain stable with various temperature changes. The considered case study is particular clock whose structural parameter tolerances often significantly affect the accuracy of the timing output of the entire movement of the mechanism in the program; the tolerance of the parts of the delay clock mechanism has been studied. By analysing the tolerance of geometric non-interference and considering the strain of the parts due to the operating temperature of the mechanism, 24% of the examined sizes should be reduced to avoid interference and the tolerance of the axis position of the clock should be reduced to ±0.01. Manuscript profile