نتایج جستجو برای: فلاتر flutter
تعداد نتایج: 4824 فیلتر نتایج به سال:
پره های هلی کوپتر و برخی از مدل های هواپیما دارای بال های بلندی هستند که در آنها انعطاف پذیری و تغییر شکل های غیرخطی نقش بسزایی خواهند داشت. در این نوع از سازه ها که دارای نسبت طول به عرض (نسبت منظری) بالایی هستند، بدلیل انعطاف پذیری زیاد سازه، خیز و تغییر شکل های بزرگ ایجاد می شوند. خیز بزرگ این ساختارها را می توان توسط مدلسازی غیرخطی توصیف نمود. حضور عوامل غیرخطی سازه ای موجب ایجاد رفتارهای ب...
pacemaker infection has multiple risk factors. its presentation is most often similar to infected endocarditis and the diagnosis is made through studying blood cultures. transesophageal echocardiography can confirm the diagnosis. the most common microorganisms are staphylococcus speciesis. as a matter of fact, complete pacemaker removal appears to be the only definite treatment. we presented a ...
در این مقاله پدیدهی فلاتر یک پوستهی استوانهای هدفمند (FGM) با تکیه گاههای ساده تحت بار آیرودینامیکی و حرارتی همراه با اعمال فشار داخلی به پوسته، مورد مطالعه قرار گرفته است. کسر حجمی مواد تشکیل دهندهی پوسته از یک قانون توانی ساده در راستای ضخامت تبعیت میکند. بار آیرودینامیک در تحلیل بکار رفته توسط تئوری مرتبه اول پتانسیل (پیستون) به صورت خطی و با در نظر گرفتن ترم تصحیح، مشخص شده است. روابط...
In a prospective, double-blind, randomized, placebocontrolled study we investigated the facilitating influence of intravenous procainamide on conversion of atrial flutter by rapid atrial pacing. Fifty consecutive patients with spontaneous sustained atrial flutter were 1:1 randomized into two homogenous groups: group A received 10 mg.kg-1 procainamide intravenously, group B placebo. After infusi...
The usefulness of flutter as a design metric is diluted for wings with destabilizing (softening) nonlinearities, as a stable high-amplitude limit cycle (subcritical) may exist for flight speeds well below the flutter point. It is thus desired to design aeroelastic structures such that the post-flutter behavior is as benign (i.e., supercritical) as possible, among the other constraints commonly ...
This paper examines efficacy of tuned mass dampers ~TMD! in controlling self-excited motion resulting from negative damping. New optimal TMD parameters are suggested which provide better performance than those suggested in the literature. The dependence of TMD performance on structural damping is highlighted. The equations of motion of a combined system comprised of multiple TMDs attached to a ...
OBJECTIVE To assess the changes in quality of life, arrhythmia symptoms, and hospital resource utilisation following catheter ablation of typical atrial flutter. DESIGN Patient questionnaire to compare the time interval following ablation with a similar time interval before ablation. SETTING Tertiary referral centre. PATIENTS 63 consecutive patients were studied. Four patients subsequentl...
In current bridge aeroelastic analysis frameworks, predictions of flutter instability and buffeting response to wind fluctuations are treated as two separate procedures. The flutter instability is analyzed through the solution of a complex eigenvalue problem, offering information on how the self-excited forces influence bridge dynamics, especially the modal damping, and eventually drive the bri...
Sixteen patients with type I atrial flutter underwent an attempt at radiofrequency catheter ablation (8 women, 8 men, mean age 53 +/- 11 years). The primary criterion used to identify sites for radiofrequency energy delivery was the identification of a fractionated electrogram. Radiofrequency energy was delivered for 20 to 30 seconds. Radiofrequency catheter ablation was acutely successful in 1...
I@? pzpz prcoents results of wind tunnel flutter tests wing a wing-G.lcron-tab model on which it was possible to represent any of the following 1P!b s~-StEm ; spring, geared, trim or servo. Prediction of the flutter-r;h?racteristics has ken made in the trim tab case using three sets of aero-dJTwic dwlvatives and fair agreement has been reached with the measured charccteristics. A comparison has...
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