Pneumatic Sensor Research Articles

The Effect of 10-degree Leg Elevation and 30-degree Head Elevation on Body Displacement and Sacral Interface Pressures Over a 2-hour Period

In Brief Objective This pilot study was undertaken to determine the effects of a 10-degree leg elevation for 30-degree head-up position on body displacement and sacral interface pressure for 2 hours. Design The study used a comparative, quasi-experimental design with repeated measures. Settings and Subjects A convenience sample of 10 healthy Japanese women was used. Instruments Body displacement was defined as the difference over time between the top edge of the mattress and subject's acromion and was measured every 10 minutes by tape measure (in centimeters). Sacral interface pressure was measured every 10 minutes using a pneumatic pressure sensor. Methods The subject was placed supine on a standard hospital bed. The head of the bed was then elevated to 30 degrees according to 2 protocols: (1) supine for 10 minutes without leg elevation alternating with 10 minutes of side-lying, or (2) supine for 10 minutes with leg elevation at 10 degrees alternating with side-lying every 10 minutes. Body displacement and mean sacral interface pressures in both protocols were compared by using repeated measures analysis of variance. Results The 30-degree head-up position with 10-degree leg elevation significantly reduced the amount of body displacement at the acromion compared with no elevation of the legs. There were no significant differences in mean sacral interface pressure in either position. Conclusion Leg elevation at 10 degrees in the 30-degree head-up position was effective for reducing body displacement at the acromion; it was not effective for reducing sacral interface pressures. This pilot study, conducted in Japan, examines the effects of a 30-degree head-up position and 10-degree leg elevation on body displacement and sacral interface pressure.

The Effect of 10-degree leg elevation and 30-degree head elevation on body displacement and sacral interface pressures over a 2-hour period

Objective: This pilot study was undertaken to determine the effects of a 10-degree leg elevation for 30-degree head-up position on body displacement and sacral interface pressure for 2 hours. Design: The study used a comparative, quasi-experimental design with repeated measures. Settings and Subjects: A convenience sample of 10 healthy Japanese women was used. Instruments: Body displacement was defined as the difference over time between the top edge of the mattress and subject's acromion and was measured every 10 minutes by tape measure (in centimeters). Sacral interface pressure was measured every 10 minutes using a pneumatic pressure sensor. Methods: The subject was placed supine on a standard hospital bed. The head of the bed was then elevated to 30 degrees according to 2 protocols: (1) supine for 10 minutes without leg elevation alternating with 10 minutes of side-lying, or (2) supine for 10 minutes with leg elevation at 10 degrees alternating with side-lying every 10 minutes. Body displacement and mean sacral interface pressures in both protocols were compared by using repeated measures analysis of variance. Results: The 30-degree head-up position with 10-degree leg elevation significantly reduced the amount of body displacement at the acromion compared with no elevation of the legs. There were no significant differences in mean sacral interface pressure in either position. Conclusion: Leg elevation at 10 degrees in the 30-degree head-up position was effective for reducing body displacement at the acromion; it was not effective for reducing sacral interface pressures. (J WOCN 2002;29:143-8.)

One-hand drive-type power-assisted wheelchair with a direction control device using pneumatic pressure

In this paper, we propose and develop a one-hand drive-type power-assisted wheelchair with a direction control device using pneumatic pressure sensors, for disabled persons who can use only their right or left arm. Compared with a joystick-type wheelchair, the advantages of the proposed wheelchair are that a disabled person can keep the functions of their arm, and can feel a sense that they are driving the wheelchair by the power of their arm. In the case of the wheelchair for disabled persons who can use only their right arm, the right wheel is rotated by the right hand and arm of the person. The left wheel is driven by an electric motor. For traveling in a straight line, the computer controls the motor as the angles of the right and left wheel are the same. When changing the direction of travel, the user uses a direction control device that consists of two vinyl tubes attached to both sides of a hand rim and pneumatic pressure sensors. Traveling experiments on a flat course with obstacles showed the validity of the proposed wheelchair system.

Changes in esophageal variceal pressure after transcatheter arterial embolization for hepatocellular carcinoma.

The aim of this study was to investigate the influence of transcatheter arterial embolization on esophageal variceal pressure and portal hemodynamics. Out of 18 cirrhotic patients with hepatocellular carcinoma, 12 underwent transcatheter arterial embolization and the remaining six patients underwent angiography alone as a control. We examined esophageal variceal pressure with an endoscopic pneumatic pressure sensor and portal blood flow with Doppler ultrasonography immediately before and 3 days after transcatheter arterial embolization or angiography. Angiography alone did not influence esophageal variceal pressure or portal blood flow. Transcatheter arterial embolization resulted in an increase in variceal pressure in five (42%) of the 12 patients and in a marked increase in portal blood flow in eight (88.9%) of nine patients, although no change in the endoscopic variceal findings was observed after transcatheter arterial embolization. The change in esophageal variceal pressure did not correlate with the change in portal blood flow. We could not find predictive factors for the elevation of variceal pressure after transcatheter arterial embolization. Our study demonstrated that transcatheter arterial embolization resulted in an increase in esophageal variceal pressure in about half of the patients, bearing little relation to portal hemodynamic parameters.

A pneumatic gauging sensor for measuring the thickness of soft films

The use of the pneumatic gauging technique for measuring the thickness of soft films of food materials on hard surfaces was investigated using devices with 45° converging nozzles and 1 mm throat i.d., at air pressures of 250–1960 Pa g and different nozzle rim widths. The quasi-linear pressure response in the gauging region (clearance of less than 300 μm) and the discharge coefficient for the nozzle at low clearances were found to be independent of the upstream pressure, nozzle Reynolds number and nozzle rim width. Draughts made measurements at low pressures difficult; therefore the results reported here are principally for gauging pressures greater than 700 Pa g. The force exerted on the surface proved to be strongly affected by the nozzle shape. The flow from narrow-rimmed nozzles behaved as impinging laminar jets, whereas wide-rimmed devices exhibited lift forces caused by inertial effects in radial flows. The former would seem to be more suitable for gauging soft films and tests on a range of foodstuffs indicated that reasonable accuracy (±20 μm) could be readily achieved on materials which present a quasi-rigid surface with low permeability. Experiments established desirable gauge design and operating procedures, namely (a) narrow-rimmed nozzles, (b) low air supply pressures and (c) performing measurements at the maximum linear clearance, at h/d t ≍ 0.25. The gauging technique failed with viscous materials lacking a finite yield stress and on soft sponges.

A Self-directed home biofeedback system for women with symptoms of stress, urge, and mixed incontinence

Purpose: To evaluate a self-directed home biofeedback treatment system in a group of community dwelling, otherwise healthy women with symptoms of stress, urge, and mixed urinary incontinence (UI). Setting and subjects: Fifty-five women, aged 25 to 81 years, participated in the study. Methods: Initial evaluation included a self-reported continence assessment, a 24-hour bladder and fluid habits diary, severity indices for stress and urge UI, and assessment of pelvic floor strength using a pneumatic biofeedback device. Subjects completed a 16-week self-directed program. Assessment and severity index data were self-reported using a continence assessment form, a 24-hour bladder habit and fluid form, and stress and urge incontinence severity indices. Strength level of the trainer, number of digital bands lit on the screen during contraction, number of sessions, and program (starter, intermediate, advanced, or maintenance) were recorded on data sheets. Instruments: The treatment system includes an 8-minute educational and motivational video; a journal for education, instructions, and daily documentation forms; and a home biofeedback trainer with pneumatic vaginal sensors that displays the strength of pelvic muscle contraction. Results: Forty-four women completed the 16-week program. At the end of treatment, 19 (43%) were dry and 16 (36%) reported 50% or more improvement in number of leaks per day, number of voids per day, or both. Women with stress leakage experienced a significant reduction in the number of incontinent episodes per day and the mean severity index of incontinence (P < .001). Participants with urge UI experienced a significant reduction in the mean number of voids per day and mean severity index for UI (P < .001). Younger subjects were more likely to improve when compared with older participants, but no significant differences were found when comparing women who take estrogen with those who do not take estrogen or when comparing those with a history of bladder surgery with those who had no previous surgery. Conclusions: These data suggest that self-selected healthy women with symptoms of urge, stress, and mixed incontinence can improve their symptoms and lower their severity index with a minimal intervention, comprehensive, self-directed home biofeedback continence system. (J WOCN 2000;27:240–6)

吸気型ボールプローブの開発 （第２報） 空気トリガセンサ式プローブの評価実験

In this paper, a novel touch trigger probe which has a totally different construction concept, namely, a pneumatic ball probe has been developed. This touch trigger type pneumatic ball probe consists of a small probe ball, a thin pipe, a pneumatic trigger sensor and a vacuum pump. The fundamental concepts and theoretical analysis of the pneumatic ball probe are described. A prototype of the probe is made and tested. From the experimental tests, the measuring force is reduced to a great extent by using this structure of separating the probe ball from the stylus. The fundamental analysis and the experiment show that it is possible to measure the distance between two walls such as a groove or a drilled hole without restriction of material for two dimension measurement. Using this pneumatic ball probe, it is found that the width between gauge blocks could be measured within a standard deviation of 1.1 μm as well as it is influenced by the vacuum of probe and the inclination of the measurement.

A development of an advanced shift control algorithm for a hybrid vehicles with automated manual transmission

In this study, an advanced shift control algorithm for a parallel hybrid drivetrain system with automated manual transmission (AMT) is proposed. The AMT can be easily realised by mounting pneumatic actuators and sensors on the clutch and on the shift levers of the conventional manual transmission (MT). By using the electronic-controlled AMT, the engine load and the induction machine, it is possible to achieve the integrated control of the overall system regarding the efficiency and the performance of the vehicle. Performing the speed control of the induction machine and the engine, the synchronisation at gear shifting and the smooth engagement of the clutch are guaranteed. It also enables the shift shock to be reduced and the shift time to be shortened. Hence, the shift quality and the driving comfort of the vehicle are improved. Various dynamometer-based experiments are carried out to prove the validity of the proposed shift control algorithm.

A biomimetic controller for a multifinger prosthesis.

A novel controller for a multifinger hand prosthesis was developed and tested to measure its accuracy and performance in transducing volitional signals for individual "phantom" fingers. Pneumatic sensors were fabricated from open-cell polymeric foam, and were interposed between the prosthetic socket and superficial extrinsic tendons associated with individual finger flexion. Test subjects were prompted to move individual fingers or combinations thereof to execute either taps or grasps. Sensor outputs were processed by a computer that controlled motions of individual fingers on a mechanical prosthesis. Trials on three upper-limb amputees showed that after brief training sessions, the TAP controller was effective at producing voluntary flexions of individual fingers and grasping motions. Signal energies were between 5 and 25 dB relative to noise from all sources, including adjacent sensors, indicating high degrees of both sensitivity and specificity for tendon-associated transduction. Finger flexions at up to three repetitions per second, and rhythmic tapping of sequential fingers were readily transduced. One amputee subject was able to play a short piano piece with three fingers, at approximately one-quarter normal tempo. TAP sensors responded linearly to graded forces from individual fingers, indicating proportional force control. Our results demonstrate the feasibility of restoring some degree of finger dexterity by noninvasive sensing of extrinsic tendons.

On the Development and Application of the Fast-Response Aerodynamic Probe System in Turbomachines—Part 3: Comparison of Averaging Methods Applied to Centrifugal Compressor Measurements

Typically several hundred million data points arise from a comprehensive measurement campaign carried out in a centrifugal compressor test rig with the fast-response aerodynamic probe system (see Part 1). In order to obtain a maximum of information about the unsteady flow at any position in this turbomachine, the time-resolved data processing method has to be optimized. In contrast to the standard time-averaged flow measurements with pneumatic probes, the objective of fast-response aerodynamic probe measurements and of data processing is to extract novel information about crucial unsteady phenomena like turbulence, row-to-row interaction, modal or rotating stall, leakage flow effects, etc. In such cases, the simultaneous measurement of static and total pressures and flow vectors is of particular interest. Novel information means the analysis of averaged and time-resolved (wavelet) spectra, autocorrelations or time averages properly conserving physical fluxes, etc. Different averaging methods are applied to compress the time-dependent data measured by a one-sensor-probe (see Part 2) in a centrifugal compressor. Such results could be used for comparison with pneumatic sensor measurements and CFD calculations. The comparison of averaging methods includes the averaging theories by Traupel and by Dzung, which are compared to simple arithmetic time averaging. From there the specific stage work is calculated. In analyzing the time dependency, several ensemble-averaging procedures for flow pressure and velocity are utilized for separating deterministic from stochastic fluctuations, extracting blade row finger prints or investigating low-frequency surge type fluctuations. With respect to the selection and overall optimization of data processing methods, an overview of generic tools is given and the modularity of the processing procedures is discussed. [S0889-504X(00)01203-4]

Study of human forearm posture maintenance with a physiologically based robotic arm and spinal level neural controller.

The goals of this research are: (1) to apply knowledge of human neuro-musculo-skeletal motion control to a biomechanically designed, neural controlled, 'anthroform' robotic arm system, (2) to demonstrate that such a system is capable of responses that match those of the human arm reasonably well in comparable experiments, and (3) to utilize the anthroform arm system to study some controversial issues and to predict new phenomena of the human motion control system. A physiologically analogous artificial neural network controller and an anatomically accurate robotic testing elbow are applied in this study. In order to build the physical elbow system to have mechanical properties as close as possible to the human arm, McKibben pneumatic artificial muscles, force sensors, and mechanical muscle spindles are integrated in the system with anatomically accurate muscle attachment points. A physiologically analogous, artificial neural network controller is used to emulate the behavior of spinal segmental reflex circuitry including Ia and Ib afferent feedbacks. Systematic experiments of elbow posture maintenance are performed and compared with physiological experimental data. New experiments are performed in which responses to torque perturbation are measured when selected afferent pathways are blocked. A 'covariance diagram' is introduced. And a linear model is used to help to analyze the roles of system components. The results show that muscle co-contraction and Ia afference with gamma dynamic motoneuron excitation are two efficient ways to increase joint stiffness and damping, which in turn reduces the mechanical sensitivity of the joint to external perturbation and shortens the settling time of the system.

CHARACTERISTICS OF PNEUMATIC PROXIMITY SENSOR USING A SWIRLING JET

In pneumatic proximity sensors of cone jet type, a high supply pressure is usually required for obtaining high output signal. Therefore, a large amount of air is consumed in this type ofsensors. We have proposed the sensing system that can be much more improved by giving swirl to the main jet of the previously reported sensing system, which is combined a proximity sensor with laminar proportional amplifiers for the purpose of lowering supply pressure and reducingair consumptions. Consequently, we have found the new sensing system made it possible to measure the gaps with high accuracy, and to detect even very light weight objects.

Portal and gastric mucosal hemodynamics in cirrhotic patients with portal-hypertensive gastropathy.

Controversy exists as to the nature of gastric perfusion in portal-hypertensive gastropathy. To investigate portal hemodynamics and gastric mucosal perfusion in cirrhotic patients with and without portal-hypertensive gastropathy, we subjected 56 cirrhotic patients with portal hypertension to portal vein catheterization, pneumatic pressure sensor technique, duplex sonography and laser Doppler flowmetry. Thirteen patients had portal-hypertensive gastropathy: In 10 it was mild, and in 3 it was severe. The presence of portal-hypertensive gastropathy seemed to be independent of age, sex, cause of cirrhosis or grade of esophageal varices. Portal venous pressure, esophageal variceal pressure, portal venous flow and congestion index in patients with portal-hypertensive gastropathy were not significantly different from the values in those without portal-hypertensive gastropathy. However, portal-variceal pressure gradient (subtracting esophageal variceal pressure from portal venous pressure) (p < 0.01) and the incidence of palisading-type esophageal varices on portography (p < 0.05) was increased in patients with portal-hypertensive gastropathy significantly more than in those without portal-hypertensive gastropathy. In the fundus, gastric mucosal blood flow was significantly higher in patients with portal-hypertensive gastropathy than in those without portal-hypertensive gastropathy, whereas in the corpus and the antrum the values were not significantly different. We suggest that the mucosa of the upper stomach in patients with portal-hypertensive gastropathy is congestive and highly perfused. The pathogenesis of portal-hypertensive gastropathy may be related to both congestion and hyperemia in the upper stomach.

Clinical significance of esophageal variceal pressure in patients with esophageal varices

In 40 patients with esophageal varices, esophageal variceal pressure was assessed endoscopically using a pneumatic pressure sensor. The effects of vasopressin or nitroglycerin on variceal pressure and endoscopic findings were also assessed in two groups of seven patients. The results were as follows: (1) Variceal pressure was increased above 250 mmH2O in all patients who had bled, and the mean variceal pressure was significantly higher in patients who had bled than in those who had not (301 +/- 47 vs. 230 +/- 58 mmH2O respectively, p < 0.001). (2) Variceal pressure correlated with endoscopic findings, determined using the criteria of the Japanese Research Society for Portal Hypertension. It was significantly higher when varices with a feature of F2-F3 or RC(+2)-RC(+3) were compared to those with a feature of F1 or RC(-)-RC(+), respectively. (3) Both groups given vasopressin or nitroglycerin had significant reductions in variceal pressure; however, there was little improvement in endoscopic findings in those given nitroglycerin, compared to the improvement in those given vasopressin. Thus, use of a pneumatic pressure sensor proved to be a pertinent tool for assessing esophageal varices, along with endoscopic signs.

Design and evaluation of a device for measurement of interface pressure

An electropneumatic device has been designed to measure the interface pressure profile under compression bandages. The device uses commercially available pneumatic sensors (Talley Group Ltd, SJ235/3) and measures interface pressure at up to eight sites simultaneously along the lower limb, with an accuracy of ± 3 mmHg. Measurements can be made in one of two modes: continuously at a rate of up to three samples per second with the results output to a suitable display device, or single measurements of interface pressure can be made and displayed on a digital display incorporated in the device. This enables the monitoring and recording of interface pressure under compression bandages during either ambulation or passive recumbency. The electropneumatic system is described together with its following characteristics: the hysteresis of the Talley pneumatic sensors, the accuracy of pressure measurement and the maximum achievable sample rate. Dynamic measurements in a single normal volunteer are shown.

Intraoperative facial nerve monitoring in posterior fossa acoustic neuroma surgery.

Intraoperative facial nerve monitoring has become an indispensable tool during cerebellopontine angle surgery. Ninety-seven patients underwent surgical removal of an acoustic neurinoma with the use of a pneumatic sensor monitoring between January 1, 1986, and December 31, 1990. In the early postoperative period, a normal or near-normal facial function (grades I and II) was achieved in 86% of the patients, a moderate dysfunction (grade III) was present in 7%, and a total or severe dysfunction (grades V or VI) was present in 6%. Normal function at 1 year was achieved in 90.5% of the patients, 4% were grade II, a moderate dysfunction (grade III) was present in 2%, and 3% showed a total or severe dysfunction (grade V and VI). The incidence of normal function decreased with tumor size, with an occurrence rate of 100%, 94%, and 91% in small, medium, and large tumors, respectively. In eight consecutive patients, all responses detected by the monitoring during the operation were collected and analyzed according to intraoperative events. Analysis of the results indicate that 95% of the 316 mechanically induced stimulations were of small or extremely small amplitude, and only 5% were of moderate amplitude. A medial-to-lateral strategy of dissection, preservation of the arachnoid veil over the facial nerve, a control by the monitoring of the amount of traction, and a more widespread use of sharp dissection were the major approaches to reduce surgical trauma during dissection.

Optical velocity sensor for air data applications

An optical velocity sensor, based on the sheet-pair transit-time technology, was designed, built to flightworthy standards, and test flown on an F-16B to 50,000 ft and Mach 1.2, as part of an optoavionic air data system. Brief descriptions of the work leading to 24 flights in January and February 1990 are given, with examples of data and discussions of experiences. Compared with conventional pneumatic sensors the system offers advantages that include potential improvements in accuracy, latency, calibration, dynamic range of speed and attitude, robustness, and possibly life, cost, and range of application, without modification of the vehicle skin contour. Measurements corresponding well with the aircraft system were obtained under all conditions except heavy cloud, which demands small design changes for future systems. The importance of modeling for software and hardware design optimization is stressed and measurements are presented.

Power budget considerations for optically activated conventional sensors and actuators

Optically powered conventional instrumentation with optical fiber links that combine the advantages of a familiar technology and of fiber optics is described. A number of examples are given of the development of pneumatic pressure sensors and actuators with reduced power consumption that are operated by optical power and incorporated with fiber-optic links. Their performance and power budget are discussed. They are particularly applicable to transmissions through regions having high EM interference, high EM pulses, and explosive, radiative, or corrosive hazards, such as in nuclear power plants, process plants, aircraft, or spacecraft. These low-optical-power transmission and operation characteristics will help to meet safety requirements and to reduce the system cost. >

On-line tool wear sensing and compensation during turning operation

Dimentional inaccuracies are one of the major problems during the turning of a long bar. This is explained by the fact that flank wear on the tool cause a a tapering effect. This paper describes the design and testing of a pneumatic feedback system that can be mounted on a centre lathe to improve the dimensional stability during turning by on-line tool wear sensing and compensation. The proposed system consists of a pneumatic sensor to sense the tool wear during machining, a pilot-controlled direction control valve to amplify the signal obtained from the pneumatic sensor and an actuating mechanism to move the tool for compensation of dimensional in accuracies. The proposed sysmtem is tested for various cutting conditions. The improvement in the dimensional accuracy is shown by taking a cut with pneumatic feedback system and the repeating the cut with identical cutting conditions but without feedback. The experimental results show that the use of the proposed feedback system results inproved dimentional accuracy.

Esophageal variceal pressure by endoscopic pneumatic pressure sensor in patients with liver cirrhosis

Esophageal variceal pressure by endoscopic pneumatic pressure sensor in patients with liver cirrhosis