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How to provide sustainable and clean sources of energy is probably the most vital question of our world today. The population growth and technology development are leading to an increase in the world energy demand and fast depletion of fuel resources. Our environment is facing critical challenges and there are serious uncertainties with the future availability of fossil fuel. The only possible remedy is to increase the share of clean and renewable energies in total energy use and to make our technology more energy efficient. Marine and offshore renewable energies are from the cleanest types that are available from the boundless energy of fluid flow in the oceans, seas, rivers and channels. In the present study, the wave energy absorption in a channel has been studied. A plate with infinite length and finite width and thickness that is placed at the bottom of a channel has been investigated to absorb the energy of gravity waves. The plate is on a viscoelastic foundation which displays linear behavior. The coupled equations of fluid and plate have been investigated to calculate the vibration characteristics of fluid surface and plate. Subsequently, a proper analysis has been done for the plate's ability to absorb wave energy.

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The tube spinning process is one of the forming processes to fabricate conical seamless tubes. This process is done warm or cold, with or without mandrel. In this article, the possibility of forming of an Al-6061 conical tube by hot die-less spinning process has been investigated. An estimation of tangential force and required power can be obtained by analytical methods. So, the ideal work and upper bound methods have been utilized to derive equations for calculation of tangential force and required power of forming. An identical result was acquired for the two methods. The proposed equations can be used in design stage of the process. Furthermore, final thickness and initial length of the tube have been calculated by using of geometrical relations and constant volume law. The proposed formulation has been compared by experimental results. The final thickness and initial length of the tube are in good agreement with experimental results. An error of 0.5% and 5.5% were observed for final thickness and initial length, respectively. The obtained equation for the final thickness is a cosine function of the conical angle. Hence, it predicts higher final thickness in comparison with the sheet spinning process.

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Objective: Cryptorchidism is the most common deficiency of the male reproductive system and most prevalent endocrine disease of boys at birth. Insufficient prenatal anti-Müllerian hormone (AMH) secretion from Sertoli cells of the testis is one of its causes. The role of this hormone and inhibin B in fertility has recently been proven. AMH is a known indicator of Sertoli cell function. The aim of this study was to assess the relationship between anti-Müllerian hormone, inhibin B, testosterone, and semen parameters in post-pubertal cryptorchidism patients. Methods: We gathered the data of this cross-sectional study from blood and semen samples of 20 patients who had a history of unilateral cryptorchidism. Patients, 20-40 years of age, referred to the Urology Ward of Shariati Hospital, Tehran, Iran. Serum levels of AMH, inhibin B and testosterone were analyzed by enzyme-linked immunosorbent assay. Semen analysis was performed by means of a computer aided semen analysis system 6.5.0. Pearson’s correlation test was used to evaluate the relationships between variables. Result: Significant positive relationships were existed between total sperm motility and sperm concentration (r=0.086; p<0.01), total motility and fast progressive motility (r=0.97; p<0.01), sperm concentration and fast progressive motility (r=0.9; p<0.01), white blood cell count and sperm concentration (r=0.63; p<0.05), white blood cell count and sperm motility (r=0.66; p<0.05), white blood cell count and sperm fast progressive motility (r=0.77; p<0.01), and testosterone levels and serum AMH (r=0.6; p<0.01). Conclusion: Cryptorchidism patients in this study had lower serum concentrations of AMH, inhibin B and testosterone than the normal limits. Despite the positive correlation between serum testosterone and AMH, none of the investigated hormones showed any significant relationship with semen parameters.