In this research, leaking flow from inside the cylinder-piston space to the crankcase through the very narrow passage in the stuffing box is numerically simulated. Two distinguish geometries are considered, and it is assumed the flow is steady, three-dimensional, non-isothermal, laminar, and compressible. The governing equations (including the mass, momentum, and energy conservations) are solved simultaneously along with the ideal equation of state by finite volume method. It is demonstrated that the Mach number is under 0.8 in the majority of the domain. Therefore, the pressure-based strategy is selected to have faster convergence. It is found that the maximum leakage rate for one-row and two-row packing is respectively 49.6 and 41 g/s obtained for a pressure difference of 70 bar. Also, it is shown that the presence of the second row is mandatory to be in safe condition. The percentage of leak control by the second row is much higher for lower pressure differences. Strictly speaking, the second row of rings decreases the leakage rate depending on the pressure difference from 7.9% to 60.7%. To the best of the authors' knowledge, this would be the first time the flow through the stuffing box is simulated.

Background: Body packing and body stuffing of illicit drugs have increased in recent decades. The drug contents of the packages vary from region to region, and there are controversies surrounding the diagnostic and therapeutic methods. The aim of this study was to explore the clinical presentations, diagnostic and therapeutic measures, and the subsequent clinical outcomes of drug concealment by people. Methods: A retrospective analysis was performed on data for all cases of body packing and body stuffing that were referred to a university hospital, in Isfahan, Iran, from Mar. 2013 to Feb. 2018. Results: Sixty-eight body stuffers and 18 body packers (n=86) were included in this study. Seventy-eight patients (90. 7%) were male, mostly aged between 20 to 40 years. There was no significant difference between the two groups with respect to the signs and symptom, hospital stay, treatment and clinical outcomes. Heroin and crystal methamphetamine, n=52 (60%) and n=22 (25%), respectively, were the most substances detected, irrespective of the concealment method. Abdominal X-ray and CT scan tests were positive for the detection of at least one packet in each of the 94. 4% of the patients. Conclusion: Heroin and crystal methamphetamine were the most common substances concealed in the bodies of the patients. Based on our findings, CT scan was more sensitive than abdominal X-ray test in the detection of illicit drug packets concealed in the patients. Close observation and whole bowel irrigation were effective therapeutic modalities in most cases. All cases were fully recovered and discharged from the hospital.

This study is designed to consider the two important yet often neglected factors, which are factory recommendation and bit features, in optimum bit selection. Image processing techniques have been used to consider the bit features. A mathematical equation, which is derived from a neural network model, is used for drill bit selection to obtain the bit’ s maximum penetration rate that corresponds to the optimum parameters for drilling. At the end, the bit with the maximum penetration rate is chosen. The results of this study showed that bit pattern can be inserted in the calculation through a proper bit image processing technique. This is to ensure that each unique bit can be discriminated from other bits. The values of mean square error and coefficient of determination (R2) were respectively found as 0. 0037 and 0. 9473, for the rate of penetration model. The image processing techniques were used to extract the bit features. The artificial neural network black box was converted to white box in order to extract a mathematical equation and visibility of the model.