Aerodynamic, Structural and Aeroelastic Design of Wind Turbine Blades

With the negative impact of conventional energy resources that have been used worldwide, there is a demand for using other resources such as wind energy. Tons of researches have been applied around the globe on the process of designing and manufacturing wind energy conversion systems. In the present chapter, we are concentrating on wind turbine blades’ structural design process. The structural design of a wind turbine blade includes defining the wind turbine loads, selecting a suitable material, creating a structural model, and solving the model using the finite element method. This process will be repeated several times until a final design is achieved. The present chapter includes a discussion on the finite element method and wind turbine aeroelasticity

Effect of adding magnesium sulphate to bupivacaine on the clinical profile of ultrasound-guided thoracic paravertebral block in patients undergoing modified radical mastectomy

AbstractBackgroundParavertebral block is an effective perioperative analgesic modality in patients undergoing breast or thoracic surgery. Several adjuvants have been reported to improve the clinical profile of local anaesthetic-induced paravertebral block. In the present study, we hypothesized that the addition of magnesium sulphate could potentiate the analgesic effects of paravertebral bupivacaine in female patients undergoing modified radical mastectomy.MethodsNinety female patients ASA physical status 1 and 2 patients scheduled for modified radical mastectomy were allocated into 2 groups (45 patients each). Group (B) received bupivacaine 0.25% 0.3ml/kg in the paravertebral space while group (BM) received 100mg magnesium sulphate+bupivacaine 0.25% 0.3ml/kg in the paravertebral space. Both blocks were done guided by ultrasound before induction of standard general anaesthetic technique which was the same in both groups. The two groups were assessed in the first post-operative 24h for post-operative visual analogue scale (VAS) scores, time to first analgesic request, total 24h morphine consumption, number of attacks of PONV and any complications from paravertebral block or from the drugs used in the study.ResultsPatients in group (BM) were found to have reduced VAS scores at 30min, 2, 4, 6, 12, 24h intervals post-operative. The time to first analgesic request was longer in patients of group (BM) with less amount of post-operative opioid consumption and consequently less number of attacks of PONV in first post-operative 24h. These results were significant with a P value<0.001.ConclusionAdding magnesium sulphate to bupivacaine in ultrasound-guided paravertebral block resulted in more efficient analgesia and opioid-sparing in female patients undergoing modified radical mastectomy

Bootstrap prediction and tolerance intervals for the Weibull regression model with censored data

The problems of constructing prediction and tolerance intervals were considered for Weibull regression models. On the extreme value distribution scale, the models have the linear form y = Xβ + σ z , =NM where y is the transformed random response vector, X is the nxq matrix containing values of the regressor variables, β is a vector of unknown regression coefficients, σ is an unknown scale parameter and z is a vector of independent standard extreme value distributed error terms. The intervals constructed include two-sided prediction intervals and one-sided tolerance intervals. Further, one-sided confidence bands were developed for percentiles. The interval procedures can be applied for randomly right-censored data or uncensored data. Maximum likelihood estimation was used in the the bootstrap technique for constructing the various intervals. A simulation study was performed to investigate the accuracy of the procedures in complete sample cases. From the simulation study, the bootstrap intervals were found to have accurate confidence levels

Efficient algorithms and models for mechanical and structural design optimization

In the present work, different algorithms and penalty methods for design optimization of mechanical elements and structures are applied. Seven robust optimization techniques and seven penalty methods are thoroughly investigated and implemented in MATLAB codes. In addition, different optimization models are compared using two benchmark problems, namely, the minimal cost design of a welded beam structure and the optimal buckling design of a functionally graded material column. A performance measure factor is defined to determine the best technique among the implemented optimization algorithms. The results are arranged and nested to make it easy for the reader to figure out each technique characteristics, and hence choose the suitable one for a specific design problem and/or application. Comprehensive computer experimentations were performed, and the best optimization techniques and models have been thoroughly demonstrated. The attained optimal solutions show that, in general, the hybrid algorithms worked better than the stand-alone ones and the sequential quadratic programming (SQP) with global search indicates a superior performance than other techniques. Finally, based on the present study, the adaptive and dynamic penalties need further investigation to become more consistent with the implemented optimization algorithms

Assessment of Pulpine Mineral effect on root maturation for immature dog teeth with infected pulp

The aim of the study was to assess the effect of pulpine mineral on root maturation for immature dog teeth with infected pulp and compare the results with Mineral Trioxide Aggregate (MTA). Materials and methods: Sixty (60) permanent dog teeth from six mongrel dogs were selected. Dogs were randomly divided into 2 equal study groups (3 dogs/ group), according to the post-treatment evaluation period. Group one (1 month, n= 30 teeth), Group two (3 months, n= 30 teeth). Each main group was then subdivided according to the materials used into 4 experimental subgroups: Pulpine mineral, n=9, MTA group, n=9, Positive control group, n=6 and negative control group, n=6. Radiographic evaluation was performed to assess the increase in the root length. Results: The results showed that after 1 month; the radiographic evaluation regarding root length revealed that the difference in root length between one month after treatment and the preoperative condition was recorded 9.94±5.19 mm in the pulpine mineral group while it was recorded 5.38±3.78 mm in the MTA group, the positive control group showed the least one in the change in the root length 1.00±1.87 mm, while the negative control group was 7.00±4.06 mm. After 3 months; results showed The difference in root length between three months after treatment and the preoperative condition was recorded 8.36±2.45 mm in the pulpine mineral group while it was recorded 8.63±5.83 mm in the MTA group, the least change in the root length was detected 1.60±3.13 mm, while the highest change was 12.00±4.90 mm which was the negative control group. Conclusion: PMIN is a promising alternative to MTA when used for pulpotomy. Clinical relevance: Vital pulp therapy in immature teeth can be done using PMIN as an alternative to MTA

Minimally invasive, no hardware subtalar arthrodesis with autogenous posterior iliac bone graft

Sixteen patients underwent minimally invasive subtalar arthrodesis through a mini-invasive approach with posterior iliac graft between 2004 and 2006. No hardware was used to transfix the arthrodesis and partial weight bearing was allowed immediately. The primary indication for surgery was the squeal of fracture os calcis in terms of subtalar joint arthritis, loss of heel height, malalignment of the hindfoot, and pain with weight bearing. There were 12 male and 4 female patients with a mean age of 30 (range 17–52). Patients were followed up for a period of 40.8 months (range 36–48 months). The mean interval from injury to fusion was 2 (+0.6) years ranging from 6 months to 6 years post fracture. The average clinical rating scale based on the American Orthopaedic Foot and Ankle Society (AOFAS) improved from 36 preoperatively to 78 at the latest follow-up (P < 0.05). Union rate was 94%. Radiographic evaluation revealed a mean increase in calcaneal inclination of 6.25 + 8.3° (P < 0.07) and a mean increase in the lateral talocalcaneal angle of 7.42 + 10.2° (P < 0.08). Complications were graft nonunion in 1 patient and transient tendoachilles tendinitis in another. This technique can be used to decrease the morbidity associated with the late complications of os calcis fractures by aligning the hindfoot, restoring the heel height and correcting calcaneal and talar inclination. It offers the advantage of early weight bearing while avoiding hardware complications

Pelvic support osteotomy by Ilizarov’s concept: Is it a valuable option in managing neglected hip problems in adolescents and young adults?

For evaluating pelvic support osteotomy as a salvage procedure in managing neglected hip problems in adolescents and young adults, PSO was performed for 20 hips in 20 patients (5 men and 15 women). The mean age was 21.5 years. The etiology was neglected developmental dysplasia of the hip in 9 patients, post-septic hip sequelae in 9 patients, and paralytic dislocation due to poliomyelitis in 2 patients. All patients were treated by two osteotomies: a proximal femoral osteotomy to support the pelvis and correct the flexion and rotational deformities of the hip and a distal varization and lengthening osteotomy. Final clinical evaluation was done 6 months after frame removal. The mean external fixation time was 6.4. Lengthening and mechanical axis parallelism was achieved in all patients. At the final follow-up and according to a predesigned scoring system, there were 7(35%) excellent results, 6(30%) good results, 7(35%) fair results, and no poor results. Hip reconstruction by Ilizarov’s concept can be technically demanding and involving lengthy period wearing the frame but found to be a valuable salvage procedure for numerous neglected hip problems particularly in young patients

Epidemiology of bronchial asthma among preparatory school children in Assiut district

Background: The prevalence of asthma and allergies is increasing in both Western and developing countries. Few studies evaluated asthma prevalence in Egypt . Objectives: Determination of the prevalence and risk factors of asthma among preparatory school children in Assiut district, in Upper Egypt. Methods: A cross sectional study was conducted among preparatory school students in Assiut city and two rural areas in Assiut district in Upper Egypt. Twelve schools were selected randomly from different regions in Assiut city and two rural areas one to the North and the other to the South of Assiut city. The total coverage of the students included was 1048 (482 boys and 566 girls). Data were collected by self-administered questionnaire (in Arabic Language) which was filled by the participants. Results: Of the 1048 positively responding subjects, 65 fitted the diagnosis of asthma with over all prevalence of 6.2%. No significant difference was found between urban and rural areas (P = 0.075). Using logistic regression analysis: a positive family history of allergy and the presence of other one or more allergic diseases were significantly associated risk factors for asthma. Exposure to dust, cigarette smoke, playing and physical activity, common cold attacks, and special food or drinks were the most common triggering factors for asthma exacerbations . Conclusion: Bronchial asthma is a significant health problem among children and adolescents in Assiut district and needs special medical care. Wider scale multi-center studies in upper Egypt and other localities of Egypt are needed to outline the profile of bronchial asthma among children and adolescents in the whole country. Keywords: prevalence of asthma, preparatory school children, Assiut districtEgypt J Pediatr Allergy Immunol 2012;10(2):109-11