Hydro- and aero-elastic response of floating offshore wind turbines to combined waves and wind in frequency domain

An analytical approach and numerical solution to determine coupled aeroelastic and hydroelastic response of floating offshore wind turbines of arbitrary shape to combined wind and wave loads is presented. The model considers simultaneously the aerodynamic and hydrodynamic loads on an FOWT and integrates these with finite element method for structural analysisdue to the combined loads. The hydrodynamic and aerodynamic loads are determined based on the linear wave diffraction theory and steady blade element momentum method, respectively, and the solution is obtained in frequency domain. The structure may be fixed or floating, located in arbitrary water depth, and may host single or multiple wind towers. The model captures the complete translational and rotational motions of the body in three dimensions, and the elasticity of the blades, tower and the floating platform. To assess the performance of the model, rigid and elastic responses of a FOWT to combined wave and wind loads are computed and compared with available laboratory measurements and other theoretical approacheswhere possible, and overall very good agreement is observed. The model developed in this study addresses directly three shortcomings of existing approaches used for the analysis of FOWTs, namely (i) determination of the elastic responses of the entire structure including the floating platform, (ii) analysis of the motion and elastic response of FOWTs in frequency domain, and (iii) assessment of responses of FOWTs with single or multiple wind towers

Dynamic response of multi-unit floating offshore wind turbines to wave, current and wind loads

Motion of a multi-unit wind-tracing floating offshore wind turbine (FOWT) to combined wave–current and wind is obtained in the frequency-domain. The linear diffraction wave theory with a Green function for small current speeds and the blade-element momentum method are used for the hydrodynamic and aerodynamic analysis, respectively. A finite-element method is coupled with the hydrodynamic and aerodynamic equations to obtain the elastic responses of the FOWT to the environmental loads. The wind-tracing FOWT consists of three 5 MW wind turbines installed at the corners of an equilateral triangular platform. The platform is connected to the seabed through a turret-bearing mooring system, allowing the structure to rotate and face the dominant wind direction; hence, the multi-unit FOWT is called the wind-tracing FOWT. In this study, rigid-body responses of the wind-tracing FOWT to waves and wind are compared with those to combined wave, current, and wind loads for several current speeds and various wave heading angles. For a chosen current speed and wave heading angle, hydro- and aeroelastic responses of the wind-tracing FOWT to combined waves, current, and wind are obtained and compared with those of the rigid structure. Discussion is provided on the effect of the wave–current interaction on the motion and elastic responses of the wind-tracing FOWT. The numerical results show that under the rated wind speed, the motion of the wind-tracing FOWT is mainly governed by the wave-induced hydrodynamic forces and moments and the presence of current results in larger elastic motion of the FOWT to the environmental loads

Dynamic response of multi-unit floating offshore wind turbines to wave, current and wind loads

Motion of a multi-unit wind-tracing floating offshore wind turbine (FOWT) to combined wave–current and wind is obtained in the frequency-domain. The linear diffraction wave theory with a Green function for small current speeds and the blade-element momentum method are used for the hydrodynamic and aerodynamic analysis, respectively. A finite-element method is coupled with the hydrodynamic and aerodynamic equations to obtain the elastic responses of the FOWT to the environmental loads. The wind-tracing FOWT consists of three 5 MW wind turbines installed at the corners of an equilateral triangular platform. The platform is connected to the seabed through a turret-bearing mooring system, allowing the structure to rotate and face the dominant wind direction; hence, the multi-unit FOWT is called the wind-tracing FOWT. In this study, rigid-body responses of the wind-tracing FOWT to waves and wind are compared with those to combined wave, current, and wind loads for several current speeds and various wave heading angles. For a chosen current speed and wave heading angle, hydro- and aeroelastic responses of the wind-tracing FOWT to combined waves, current, and wind are obtained and compared with those of the rigid structure. Discussion is provided on the effect of the wave–current interaction on the motion and elastic responses of the wind-tracing FOWT. The numerical results show that under the rated wind speed, the motion of the wind-tracing FOWT is mainly governed by the wave-induced hydrodynamic forces and moments and the presence of current results in larger elastic motion of the FOWT to the environmental loads

Efficacy of sexual counseling based on PLISSIT model on sexual functioning in women with polycystic ovarian syndrome

Background and purpose: Women with Polycystic Ovarian Syndrome (PCOS) suffer from sexual dysfunction that is largely ignored in health clinics. This study was conducted to assess the efficacy of Permission, Limited Information, Specific Suggestion, Intensive Therapy (PLISSIT) model on sexual function of women with PCOS.. Materials and methods: This randomized clinical trial was performed in 66 women with PCOS aged 18-45 years old. They were divided into intervention and control groups (n=33 per group). Four weekly sessions of one hour individual counseling based on PLISSIT model were performed for the intervention group, while the control group received only routine care. Female Sexual Functioning Index questionnaire was completed at pre-test, and one month and three months after that in both groups. Data analysis was done applying Friedman, Mann-Whitney U, and Wilcoxon tests. Results: There were homogeneity in subjects� mean age (29.26±5.96), educational level (12.02±2.65) and BMI (25.95±3.67). Also, the two groups were similar in terms of symptoms including hirsutism, acne, alopecia, infertility and menstrual status. The mean scores for sexual functioning were 20.39±2.56, 24.40±4.70 and 23.73±1.26 at pre-test, after the intervention, and follow-up in intervention group, respectively (P<0.001), but no significant differences were seen between the scores of the control group (P=0.405).Also, the scores for lubrication were not significantly different between the two groups at post-intervention (P=0.245) and follow-up (P=0.423). Conclusion: The PLISSIT model improved sexual functioning in women with PCOS, therefore, it could be recommended as an assessment and management tool in investigating sexual problems at early stages in this group of women. © 2019, Mazandaran University of Medical Sciences. All rights reserved

Factors affecting quality of care in family planning clinics: A study from Iran

Background. Despite good contraceptive coverage rates, recent studies in Iran have shown an alarmingly high incidence of unplanned pregnancy. Objective. To determine factors affecting quality of family planning services, a cross-sectional study was performed from June to August 2006 on women visiting urban Primary Health Care clinics in a provincial capital in western Iran. The primary focus of the study was on provider-client interaction. Method. We used a slightly edited version of a UNICEF checklist and a convenient sampling method to assess quality of care in 396 visits to the family planning sections at 25 delivery points. Results. Poor performance was observed notably in Counselling and Choice of method sections. In logistic regression analysis, the following factors were found to be associated with higher quality of care: provider experience OR (odds ratio) = 1.9, CI0.95 (confidence interval) = 1.2-3.0, low provider education (OR = 6.7, CI0.95 = 4.0=10.8), smaller workload at the clinic (OR = 3.7, CI0.95 = 2.0-6.7), and 'new client' status (OR = 4.2, CI0.95 = 2.6-6.7). Conclusion. This study identified the issues of counselling and information exchange as the quality domains in serious need of improvement; these areas are expected to be the focus of future training programmes for care providers. Also, priority should be given to devising effective supervision mechanisms and on-the-job training of senior nursing and midwifery graduates to make them more competent in delivering basic family planning services. © The Author 2008. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved

Effect of the sexual education program on the knowledge and attitude of preschoolers� mothers

Introduction: Sexual instinct needs education and training similar to other aspects of the human life. Education can promote changes in knowledge and attitudes of parents, especially mothers. Education has a main role in teaching healthy sexual behaviours among pre-school age children. Aim: To investigate the effect of the sexual education program on the knowledge and attitude of preschoolers� mothers. Materials and Methods: This quasi-experimental study was consucted in two healthcare centers in an urban area of Iran. Study subjects were preschoolers� mothers, which were selected using a multistage method. For each control and experiment groups, 39 individuals each were selected. The experiment group participated in four educational sessions in four weeks, one session per week. A self-administered questionnaire was developed for data collection. Descriptive and inferential statistics were used for data analysis. Results: Statistically significant differences in the mean score of knowledge and attitude between the groups immediately and eight weeks after the education program were reported (p < 0.001). The mean score of knowledge was increased from 27.23 to 34.2 immediately and to 37.44 eight weeks after the education program. The mean score of attitude in the experiment group significantly was increased from 48.54 to 59.15 immediately and to 64.49 eight weeks after the intervention (p < 0.001). Conclusion: The sexual education program influenced the knowledge and attitude of preschoolers� mothers. Therefore, mothers should be empowered regarding children�s sexual education. © 2018, Journal of Clinical and Diagnostic Research. All rights reserved

Natural killer cells suppress cancer metastasis by eliminating circulating cancer cells

Despite significant advances in cancer treatment, the metastatic spread of malignant cells to distant organs remains a major cause of cancer-related deaths. Natural killer (NK) cells play a crucial role in controlling tumor metastasis; however, the dynamics of NK cell-mediated clearance of metastatic tumors are not entirely understood. Herein, we demonstrate the cooperative role of NK and T cells in the surveillance of melanoma metastasis. We found that NK cells effectively limited the pulmonary seeding of B16 melanoma cells, while T cells played a primary role in restricting metastatic foci growth in the lungs. Although the metastatic foci in the lungs at the endpoint were largely devoid of NK cells, they played a prominent role in promoting T cell recruitment into the metastatic foci. Our data suggested that the most productive interaction between NK cells and metastatic cancer cells occurred when cancer cells were in circulation. Modifying the route of administration so that intravenously injected melanoma cells bypass the first liver passage resulted in significantly more melanoma metastasis to the lung. This finding indicated the liver as a prominent site where NK cells cleared melanoma cells to regulate their seeding in the lungs. Consistent with this notion, the liver and the lungs of the tumor-bearing mice showed dominance of NK and T cell activation, respectively. Thus, NK cells and T cells control pulmonary metastasis of melanoma cells by distinct mechanisms where NK cells play a critical function in shaping T cell-mediated in situ control of lung-seeded cancer cells. A precise understanding of the cooperative role of NK and T cells in controlling tumor metastasis will enable the development of the next generation of cancer immunotherapies