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. methods thirty si...

Pneumatic servo systems are applied in several industrial applications and have also been studied extensively for the purposes of compensating the nonlinearity of pneumatic servo systems and improving the controllability with robust control. In their control system design, the transfer function of a pneumatic servo system has been a third-order time lag system, based on the assumption that serv...

BACKGROUND/AIM Pneumatic caisson engineering has been developed for large civil engineering constructions. Because of complaints of blurred vision by personnel working in pneumatic caissons, the development of myopia was suspected. The aim of this study was to determine the cause of the blurred vision and the mechanism underlying the changes. METHODS 12 caisson workers underwent a complete op...

Based on the theoretical analysis and experimental study of pneumatic damping behaviour for the valves in the reciprocating compressor, this paper presents a simple mathematical model of pneumatic damping valves, in which the non-viscous damping force is introduced. The non-viscous damping coefficient is obtained by the experimental determination. The simulation results of this simple model for...

Pneumatic actuation systems are widely used in industrial automation, such as drilling, sawing, squeezing, gripping, and spraying. Also, they are used in motion control of materials and parts handling, packing machines, machine tools, food processing industry and in robotics; e.g. two-legged robot. In this paper, a Neural Network based intelligent PI controller is designed and simulated to incr...

It is a general assumption that pneumatic muscle-type actuators will play an important role in the development of an assistive rehabilitation robotics system. In the last decade, the development of a pneumatic muscle actuated lower-limb leg orthosis has been rather slow compared to other types of actuated leg orthoses that use AC motors, DC motors, pneumatic cylinders, linear actuators, series ...

AIM To evaluate the success rate and complications of pneumatic retinopexy performed at a university hospital and to identify which patients are best suited for pneumatic retinopexy. METHODS This was an interventional case series. Retrospective review of 61 patients who had pneumatic retinopexy performed by two retina surgeons at two University of California, San Francisco hospitals between 1...

Pressure control of a pneumatic actuator using fast switching On/Off valves continues to remain a major challenge for researchers. This article proposes a novel pulse width modulation–sliding mode controller that improves pressure tracking of pneumatic actuators. First, a comprehensive mathematical model of the pneumatic system was developed that consists of several submodels. The model compris...

PURPOSE The purpose of this study was to evaluate the role of pneumatic retinopexy as an initial management of retinal detachment associated with hypotony, severe choroidal detachment, and vitritis. METHODS Retrospective, interventional, noncomparative case series. We included nine eyes from nine patients (six women and three men) with retinal detachment associated with hypotony, severe choro...

For a pneumatic teleoperation system with on/off solenoid valves, sliding-mode control laws for position and force, ensuring low switching (open/close) activity of the valves are developed. Since each pneumatic actuator has two pneumatic chambers with a total of four on/off valves, sixteen possible combinations (“operating modes”) for the valves’ on/off positions exist, but only seven of which ...