Controlling wind turbine tower vibration under external force by applying control systems combination.

The global focus has recently shifted away from fuel-based power sources, and one of the most important projects for energy production is wind energy. To maintain low costs, the current research examines the problem of vibrations affecting wind turbine towers' performance (WTTs). In particular, the tower, resulting from excessive vibrations, can negatively affect a structure's power output and service life, as it can cause fatigue. Therefore, we conducted numerical tests on various types of controlled systems. Our tests revealed that combining a new technique cubic negative velocity control (CNVC) and linear negative acceleration control (LNAC) was the most effective and cost-efficient option for vibration damping. This solution was derived by using an approximation method for the averaging technique. The external force is an important component of a nonlinear dynamic system and can be characterized by two-degree-of-freedom (2-DOF) differential coupled equations. After implementing the control measures, we conducted a numerical analysis of the vibration values before and after the operation. Stability is studied numerically. The numerical and approximate solutions were confirmed through the frequency response equation and time history with fourth-order Runge-Kutta (RK-4). Finally, we investigated the effect of parameters and compared our results with those of previously published studies.

Serum KL-6 as predictive and prognostic marker of interstitial lung disease in childhood connective tissue diseases: a pilot study.

This study was aimed to evaluate serum KL-6 levels to determine if this marker can be used for diagnosing and assessing severity of interstitial lung disease (ILD) in children with connective tissue disorders. In total, 40 patients [18 patients with juvenile systemic lupus erythematosus (JSLE), 10 patients with juvenile idiopathic arthritis (JIA), 8 patients with juvenile mixed connective tissue disease (JMCTD), 3 patients with juvenile systemic sclerosis (JSSc), and 1 patient with juvenile dermatomyositis (JDM)] and 20 healthy controls were included in this study. Age, sex, and duration of CTD and ILD (if any) were recorded. Blood samples from all the patients and controls were examined by ELISA. 20 of the 40 patients with CTD (50%) had ILD, 12 were mild and 8 were severe as assessed by spirometry. The median serum KL-6 level was 102.7 U/mL (76.1-180.8) in the CTD with severe ILD group, 72.2 U/mL (58.4- 100.5) in the CTD with mild ILD group, 56.7 U/mL (35.8-68.5) in the CTD without ILD group, and 52.3 U/mL (32.8-62.4) in the control group. KL-6 levels were significantly higher in the CTD with ILD (p<0.05), at a cutoff of 63.4 U/ml identified by ROC curve, serum KL-6 showed a sensitivity of 95.2% and specificity of 89.7%. KL-6 is a valuable biomarker for diagnostic purposes and to detect severity in ILD in childhood CTD.

Impact of ultrasonography detected quadriceps calcific tendinopathy on pain and function in patients with primary knee osteoarthritis.

Calcific tendinopathy is most commonly seen around the shoulder joint. Only a few cases of quadriceps calcific tendinopathy (QCT) were reported. This study compares pain, function, clinical examination results, and ultrasonographic findings among primary knee osteoarthritis (KOA) patients with or without ultrasonography-detected QCT. A cross-sectional study was conducted on 214 patients with knee OA. Ultrasonography (US) of knee joints was performed according to the EULAR guidelines. Kellgren-Lawrence radiographic grading was used to score OA. Pain and functional status were assessed using the visual analog scale (VAS), the Health Assessment Questionnaire-II (HAQ-II), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). QCT was detected in 50 out of 428 knees (11.6%), i.e. in 46 out of 214 patients (21.49%). Most cases of QCT were detected in the following sites: 36 in the vastus lateralis (72%), 10 in the vastus intermedius (20%), and only 4 in the vastus medialis (8%). QCT was found mainly in advanced KOA stages: 44 cases of QCT were found in patients with grade 4 KOA and 6 cases in grade 3 KOA. The presence of QCT showed a statistically significant association (p<0.05) with VAS, HAQ-II, WOMAC subscales, synovitis, and effusion detected by US. In knees with ultrasound-detected QCT, ultrasonographic features of CPPD were found in 31 knees (62%). QCT was found in cases with advanced KOA and mainly with ultrasonographic findings of CPPD disease. QCT could be considered an independent poor prognostic finding regarding pain, functional activity, and response to NSAIDs.

Comparative study between laparoscopic and open repair of paraumbilical hernia.

UNLABELLED: This randomized prospective study compared the effectiveness of laparoscopic paraumbilical hernioplasty to the conventional open technique. Forty patients with paraumbilical hernia were randomly categorized into 2 equal groups. GL treated by laparoscopic paraumbilical hernioplasty and GO treated by conventional (open) umbilical hernioplasty. The mean length of follow up was 36 months. In GL, mean operative time was 58.1 +/- 15.5 minutes, in GO, it was 42.2 +/- 10.3 minutes (p = 0.0005). Postoperative pain score 6 hours after surgery was 2.95 +/- 1.19 in GL patients as compared to 6.10 +/- 1.74 in GO ones (p < 0.0001). Mean hospitalization time was 1.05 +/- 0.224 days in GL versus 1.25 +/- 0.550 days in G O (p = 0.14). There was one conversion (5%) to the open repair. Postoperative seroma occurred in 2 patients (10%) in GL and 3 patients (15%) in GO. Three patients (15%) in G O developed surgical site infection. Hernia recurrence was not seen in either 2 Groups. Mean patient satisfaction score for GL patients was 7.85 +/- 1.27 versus 6.00 +/- 1.69 for GO patients (p = 0.0004). CONCLUSION: Compared to open repair, laparoscopic repair is technically feasible, safe and effective, with good clinical outcome. It is associated with longer time for surgery but reduced postoperative pain, analgesic requirement, complication and infection rates with earlier return to normal activities.