Grinding of riblets with "beaver tooth" multi-layer tools

To reduce friction in turbo machinery components, riblets are induced on compressor blades or pump impellers. Here, the grinding process enables a higher productivity in machining of riblet structures compared to knurling, laser or milling operations. Usually, profiled grinding tools are used to create such structures inspired by sharkskin. Unfortunately, conventional grinding tools have to be dressed continuously to keep the desired profile in the circumferential surface. To avoid the time-consuming dressing process and to enable a self-sharpening effect, an innovative multi-layer tool concept is developed. The tool consists of two types of thin polyimide layers. The first type contains abrasives and the second is a support layer without abrasives. These layers are piled alternately in a special manufacturing process and act like a monolithic tool in grinding process. The aim of the investigations presented in this paper is to find an optimal parameter setting to produce riblet structures productively by using the self-sharpening effect. The optimal setting allows a grinding process without any dressing process by using a large part of the grinding tool volume. At first, the manufacturing process is focused to create clearly divided support and abrasive layers of the grinding tool. Furthermore, the investigation shows the relationship between grinding parameters and the setback of the supporting layer in the middle of the tool. This setback is important for the creation of riblet structures in the surface of AISI 420 workpieces

Effect of organizational citizenship behavior on family-centered care: Mediating role of multiple commitment.

Family-centered care is one the most important indicators of high-quality care. The organizational citizenship behavior and commitment can enhance the quality of healthcare. This study aimed to investigate the effect of the organizational citizenship behavior on family-centered care considering the mediating role of multiple commitment. This descriptive study was conducted on 237 nurses working in pediatric and infant units of hospitals in Tehran city, Iran. The subjects were selected using the convenience sampling method. Data collection was performed using the Organizational Citizenship Behavior Scale, Perceived Family-Centered Care Staff Questionnaire, Affective Commitment Scale, and Commitment to the Supervisor Scale. The SPSS v.22 and SEM-PLS v.2 software were used for data analysis. Results were extracted in the form of a standard model and fitted for indices pertaining to the measurement and structural models. Accordingly, the organizational citizenship behavior had a direct effect on family-centered care (β = 0.19, t = 2.39). Moreover, multiple commitment including commitment to the leader and commitment to the organization had indirect weak and moderate effects on the relationship between the organizational citizenship behavior and family-centered care, respectively. An inverse association was reported between commitment to the leader and family-centered care. Furthermore, the organizational citizenship behavior predicted family-centered care by 70% considering the mediating role of multiple commitment. Therefore, family-centered care as an indicator of high-quality care can be improved through enhancing the organizational citizenship behavior and organizational commitment among Iranian nurses working in pediatric wards