The creating SCRATCH by an ABRASIVE grit is mostly investigated to enhance the finishing processes. In grinding, many distributed ABRASIVE grits on grinding wheel surface are engaged with the workpiece to remove material. To investigate the material removal mechanism in grinding process a SCRATCH and removed material by an ABRASIVE grit is assumed and simulated. The results are developed for all engaged ABRASIVE grits on grinding wheel surface. This leads to improve the machining process and gaining deeper insight to the grinding mechanism. By analyzing a creating SCRATCH by a single ABRASIVE grit, the material removal mechanism is scrutinized from a different view. The effect of grinding wheel surface topography and input parameters on material removal mechanism is investigated. Results show that increasing cutting speed leads to changing material removal mechanism from ploughing to cutting. The shape of ABRASIVE grits has more effect on material removal mechanism. In worn grits increasing the cutting depth causes the ploughing to become the dominant mechanism in machining. This leads to less cutting efficiency. But in ABRASIVE grits with sharp single cutting edge the converse result is achieved. When grit breaks down and self dressing occurs during machining, the multiple edges are formed on grit and the grit acts like a dull ABRASIVE.

In this paper، how to use the ABRASIVE wheel in the pin on disk test was evaluated and developed for tribological studies of steels. Parameters such as type of pin (steel), type of ABRASIVE wheel، normal load on pin, linear velocity of disk and sliding distance were studied. The results showed that initial hardness can not merely determine the wear resistance of a metal whereas it may be related to the surface hardness resulting from work hardening during ABRASIVE. In addition, in the pin on disk method, using the ABRASIVE wheel is a good choice for evaluation of tribological behavior of high wear resistance metals such as Hadfield steels while, it is not appropriate and proper for mild steel.

Objective: To examine the timing of endometrial SCRATCH in a patient’, s menstrual cycle and whether there is an association with subsequent implantation. Materials and methods: This study is a retrospective chart review on women, aged 18-45, seen in a reproductive endocrine clinic seeking conception. Timing of endometrial SCRATCH was defined as proliferative (cycle day 1-9), periovulatory (CD11-16), or secretory (CD19+). All periovulatory biopsies were performed at time of oocyte retrieval in women freezing all oocytes/embryos for future use. Primary outcome of interest was positive beta-hCG within ninety days of the endometrial SCRATCH. Results: Sixty-nine cases of endometrial SCRATCH met the inclusion criteria. There were no statistically significant differences in baseline demographic characteristics between those who received endometrial injury in the three phases. There was no significant difference in frequency of positive beta-hCG within 90 days of endometrial SCRATCH between the patients who received an endometrial SCRATCH in the three phases (proliferative 65. 6%, periovulatory 69. 6%, secretory 64. 3%,p = 0. 9332). Conclusion: In contrast to prior studies which showed up to 65% decrease in implantation rate after endometrial SCRATCH performed at time of oocyte retrieval, this study shows no significant difference in implantation when the injury is performed at the time of oocyte retrieval as compared to other phases of the menstrual cycle. Possible explanation may be that we did not perform a SCRATCH if fresh embryo transfer was planned. As endometrial injury is associated with patient discomfort, performing the SCRATCH while under conscious sedation for oocyte retrieval may be desirable in cycles where fresh embryo transfer is not planned. Future studies are needed to assess the validity of these findings.

Objective: The main purpose of this study was to develop a simple reproducible system to compare ABRASIVE effects of three different toothpastes.Materials and Methods: A specific mold was used to fabricate 37 samples made of po-lymethylmethacrylate. The samples were stroke by toothbrushes connected to a V8 Cross Brushing Machine in a solution of fluoridated toothpastes and distilled water. The samples were evaluated initially and also after 48 hours. The data were analyzed by one-way ANOVA test.Results: No significant differences was found among the three types of toothpastes after 25000 strokes (P=0.427).Conclusion: All the three toothpastes presented same ABRASIVE properties.