نتایج جستجو برای: pneumatic dilation

تعداد نتایج: 22052  

Journal: :AORN journal 2013
Rodney W Hicks Bonnie Denholm

Perioperative nurses are likely to encounter the use of pneumatic tourniquets in a variety of operative and invasive extremity procedures. Use of a pneumatic tourniquet offers an opportunity to obtain a near-bloodless surgical field; however, the use of tourniquets is not without risk. Unfavorable outcomes include pain, thrombotic events, nerve compression injuries, and disruption of skin integ...

Journal: :Journal of Advanced Mechanical Design, Systems, and Manufacturing 2008

Journal: :medical journal of islamic republic of iran 0
j mikaeli from the department of gastroenterology and digestive disease research center, shariati hospital, tehran university of medical sciences, tehran, i.r. iran r malekzadeh m khatibian r ansari h vahedi h solimani

between 1993-1996 seventy-three consecutive patients (33 m, 40 f, mean age 35.4) with newly diagnosed achalasia underwent one or more pneumatic dilatations with the rigiflex balloon using a protocol of graded dilatation with a fixed inflation pressure of 10 psi and constant duration of 30 seconds for all patients without using fluoroscopy. using vantrappen's classification for assessment o...

2001
Eric J. Barth Jianlong Zhang Michael Goldfarb

This paper presents a rigorous analysis and design method for PWM-based control of pneumatic systems. An equivalent analytical model incorporating the effects of a finite PWM switching period is formulated. This equivalent model was motivated by a lack of control design and analysis techniques needed to treat the inherently non-analytical switching models associated with PWM-based systems. The ...

2016
Tudor Deaconescu

Abstract—The utilization of pneumatic muscles in the actuation of industrial systems is still in its early stages, hence studies on the constructive solutions which include an assessment of their functional performance with a focus on one of the most important characteristics-energy efficiency are required. A quality indicator that adequately reflects the energy efficiency of an actuator is the...

2002
J. M. Tressler T. Clement Homayoon Kazerooni M. Lim

AbstructThis article models a pneumatic system consisting of double-acting or single acting cylinder and a servovalve with the goal of providing an insight into pneumatic design and control requirements for Berkeley Exoskeleton (ht<v://wwu..me. berkeZev.edu/heZ/). The modeling approach uses the thermodynamic principles of energy and mass conservation. We demonstrate that pneumatic systems suffe...

2006
Xiaocong Zhu Guoliang Tao Jian Cao Bin Yao

Considering rather severe parametric uncertainties and nonlinear uncertainties exist in the dynamic model of pneumatic muscles driven parallel manipulator, a discontinuous projection-based adaptive robust control strategy (ARC) is adopted to effectively handle the effect of various parameter variations of the system and hard-to-model nonlinearities such as the friction forces of the pneumatic m...

2015
JÁN PITEĽ MÁRIA TÓTHOVÁ STELLA HREHOVÁ ALENA VAGASKÁ

Pneumatic artificial muscles exhibit highly non-linear static characteristics especially due to inherent properties of their materials and compressibility of air. Therefore, it is difficult to control them without adequate modeling and simulation. The paper deals with the numerical approximation of the static characteristics of McKibben pneumatic artificial muscle. The muscle force dependence o...

Journal: :Middle East journal of digestive diseases 2016
Mohammad Amani Narges Fazlollahi Shapour Shirani Reza Malekzadeh Javad Mikaeli

UNLABELLED BACKGROUND Although Heller myotomy is one of the most effective treatments for achalasia, it may be associated with early or late symptom relapse in some patients. Therefore, additional treatment is required to achieve better control of symptoms. AIM To evaluate the safety and efficacy of pneumatic balloon dilation (PBD) in patients with symptom relapse after Heller myotomy. METHOD...

2005
Achim Ilchmann Oliver Sawodny Stephan Trenn

In this paper, we model, analyze, and control an experimental set-up of a servo pneumatic cylinder. The dynamic behaviour of pneumatic actuator systems is dominant by nonlinear functions. First, a mathematical model for the pneumatic system is derived. Secondly, we investigate the mathematical properties of this model and show boundedness and positiveness of certain variables. Thirdly, we prove...

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