Partially submerged propellers function in two-phase condition, i. e. each propeller blade enters water once in each revolution so the thrust and torque of each blade hit maximum level and then become around zero. Surface-piercing propeller investigated in this work is a new geometry that the main purpose of its design has been to achieve higher hydrodynamic performance; minimizing energy loss by reducing of the volume fraction of the water adhered to the exiting blade from the water surface. In this article, Reynolds-Averaged Navier– Stokes computations based on finite volume method (FVM) was applied to investigate force excitation, ventilation pattern and Wake formation of the partially submerged propeller under inclination angle. Two-phase flow field equations were solved using homogenous Eulerian multiphase model by sliding method. To solve two-phase flow field at the free surface accurately and deal with free surface effects in calculations, CFX free surface model based on volume of fluid (VOF) approach was used. The accuracy of the numerical method was verified using series of simulations on SPP-841B propeller with existing experimental measurements. Comparison between simulated and measured SPP-841B open characteristics as well as ventilation pattern of the key blade indicated a reasonable agreement with experimental data and observations. Based on obtained data, with an increase in shaft inclination angle, propeller thrust and torque coefficients increased, whereas the propeller efficiency was decreased.

Background and Objective: Obstructive sleep apnea (OSA) is a common sleep breathing disorder and a comorbid condition in patients with stroke. The prevalence of sleep disorders as a stroke consequence is high. Being independent of vascular risk factors, OSA is associated with increased risk of ischemic stroke. Here, we report a patient with OSA and stroke. Case Report: This case report presents a patient with a history of stroke and hemiparesis who underwent polysomnog-raphy (PSG) for evaluating OSA because of snoring, witnessed apnea, and excessive daytime sleepiness (EDS). Then the subject underwent continuous positive airway pressure (CPAP) titration for treating OSA. In first night of PSG, there was a repetitive cyclic pattern of sleep and arousals. After CPAP titration study and with CPAP pressure of 15 cmH2o, OSA and rhythmic changes of electroencephalography (EEG) were resolved. Conclusion: OSA as a risk factor for stroke can be associated with PSG cyclic Wake-sleep pattern in these patients, and this pattern can be resolved by CPAP therapy.

The aim of this narrative review is to investigate the reciprocal correlation between melatonin through the brain's central clock management on sleep-Wake behavior in women with polycystic ovary syndrome (PCOS). Biological clocks are genetically programmed physiological systems that permit organisms to live in harmony with natural rhythms. The most important function of a biological clock is to regulate overt circadian biological rhythms. Circadian rhythms orchestrate the body's rhythmic physiologic functions like sleep-Wake and menstruation cycle. Stress hormones, beta-endorphins, and melatonin which can easily affect the woman's reproductive system. For example, amplitude changes in the luteal phase are one of the results of menstrual-related disorders that occur through this circadian fluctuation. Many reports indicate that levels of melatonin and stress hormones are altered in women with PCOS. The melatonin metabolites are significantly raised in the level of night-time urinary in women with PCOS, which is associated with a significant reduction of sleep quality compared to normal women. The result of this narrative review showed the circadian rhythm as a normal coordinated function is a regulator of the natural structure of sleep-Wake architecture. Disruption of this natural pattern can lead to phasic activation of the HPA axis, which increases the continuation of circadian activation,which there is in women with PCOS.

Wind turbines operate mostly in yaw conditions that give rise to cyclic variations in aerodynamic forces applied on the blade. This induced load fluctuation is closely related to the upstream velocity field of the rotor and can be a significant source of fatigue and vibration. An accurate prediction of blade loading is considered the key in designing reliable and efficient wind turbines. The related calculation remains a complicated task to perform and requires enormous computing time. In this context, a numerical method is presented, aimed at evaluating the azimuthal fluctuation of the normal force. This method is obtained by coupling the Beddoes near-Wake model and the free-Wake method: the near-Wake-induced velocities are calculated using Beddoes near-Wake model with the far-Wake contribution evaluated using the free-Wake method. In addition, the unsteady effects on the aerodynamic coefficients are taken into account using the Beddoes-Leishman dynamic stall model. A computer code was developed, and numerical values were obtained in acceptable computational time. Results are compared with measurements performed in the NASA Ames wind tunnel.