Pneumatic Device Research Articles

공압식 박동형 심실보조장치에서 공압관 내 공기압에 따른 박출량 추정

심실보조장치는 심장질환자에게 심장이식까지의 가교로서 사용된다. 공압식 박동형 심실보조장치를 체내에 이식했을 때, 심실보조장치를 통과하는 혈류가 느려질 경우 혈전이 발생할 수 있기 때문에 박출량을 측정하는 것이 중요하다. 심실보조장치의 박출량을 측정하기 위해 각종 센서를 함께 이식할 경우, 감염의 위험성이 커지기 때문에 본 연구에서는 체외에서 측정할 수 있는 공압관 내 압력을 통해 심실보조장치의 상태를 추정하고자 한다. 체외실험을 통해 공압식 박동형 심실보조장치의 공압관 내 차동압력과 심실보조장치 박출량의 상관관계를 계산하였다. Pearson correlation coefficient r=0.623 으로 두 값의 상관관계가 높으며, 박출량 추정값과 측정값에서 오차가 있었지만 공기 분자의 이동에 따른 식을 개발하여 박출량 추정의 정확성을 높일 수 있을 것으로 보인다.

공압식 박동형 심실보조장치의 공압관 내 압력 측정을 통한 박출량 추정

Abstract: A Ventricular assist device (VAD) is one of the most efficient treatments to raise the survivability of theend stage heart failure patient. However, some of LVAD patients have died for the failures and improper control ofLVAD. To detect critical dangers in LVAD, the monitoring methods of LVAD outflow have been requested, becauseit can be affected by patient’s hemodynamic states and abnormal conditions of LVAD. In the case of an external pul-satile LVAD, the air movement through the air line can be used to estimate LVAD outflow. In this study, the air move-ment in the air-line of the extracorporeal pulsatile LVAD was measured with a differential pressure sensor betweendifferent points. The precise estimation of air movement could be achieved by additional measurement of air pres-sure. In a series of in-vitro experiments, the LVAD outflow were changed according to the afterload of LVAD andthe differential pressure of LVAD didn’t have close correlation with the LVAD outflow that were measured with anultrasonic flowmeter at the same time. However, new precise estimation with the data from differential pressure andone point pressure in the air-line showed higher correlations with LVAD outflow.Key words: Pneumatic Pulsatile Ventricular Assist Device, VAD Pump Outflow, Air Pressure, Air Flow

대형 유연박판 회전이송용 비접촉 파지시스템 설계

This paper describes an improved design model that can be used to configure a non-contact pneumatic device to turn a large sheet at the in-line system. For rotational moving in the conveyor system, the conventional method is to turn the system itself. The improved non-contact pick-up system mainly uses 8 pairs of L-shaped latches and 12 swirl type heads. It is positioned above the upward air flow table. This system performs the non-contact gripping and side-edge contact support in the vertical and rotational directions to hold the self-weight of a large flat sheet. A non-contact air head can exert a sufficient gripping ability at 4N lower than the standard working pressure. The side latches support 60% of the lifting force required. Through structural and flow analysis, the working conditions were simultaneously considered in accordance with the deflection and flatness of the glass.Received 5 September 2014Revised 8 October 2014Accepted 10 October 2014

Thermal Borehole Shear Device

This paper presents the details of a new modified borehole shear device that has the capability of measuring the impact of temperature on the in situ shear stress–displacement curves for soil–concrete interfaces. The thermal borehole shear device incorporates concrete shoes with embedded heaters, a pneumatic loading device for application of horizontal normal stresses, and an automated loading system with local vertical displacement and load measurement systems that permits either displacement–control or load–control testing. A methodology for measurement of the soil–concrete shear stress–displacement curves and for evaluation of the drained interface shear strength failure envelopes at different temperatures is presented in this study. Typical results from proof-of-concept tests performed in a clay layer compacted in a laboratory tank in a borehole in a silty sand deposit in the field are presented in this paper. The results are synthesized to show how the impacts of temperature and normal stress on the normalized shear stress–displacement curves can be evaluated. These normalized curves can be measured on a site-specific basis for the calibration of thermo-mechanical load transfer analyses or finite element analyses, which are often used to design and evaluate soil–structure interaction in drilled shaft foundations with geothermal heat exchangers (energy foundations).

Digital sowing device

Advantages of precision agriculture are described. Urgency of development of digital pneumatic device for precision sowing is substantiated. Criteria which the device should meet and its functional diagram are given. Design, operating principle and processes occurring inside the device during seeds dispensing are considered.

Multi-fingered haptic palpation using pneumatic feedback actuators

This paper proposes a multi-fingered palpation method which employs pneumatic haptic feedback actuators allowing users to experience haptic sensations at multiple fingers while carrying out remote soft tissue palpation. Pneumatic actuators are used to vary the stress on the user's fingertips in accordance with the tissue stiffness, experienced during manual palpation. The proposed method reduces actuator elements compared to tactile actuators and provides more information than single-point force feedback. The results of our finite element analysis have proven that our pneumatic haptic feedback device can recreate the contact stress between fingertip and soft tissue during palpation. The accuracy (96.8% vs. 93.3%) and time-efficiency (4.6s vs. 8.3s) advantages of using three-fingered over single-fingered palpation have been confirmed in our user study results of stiffness levels discrimination. Relatively good tumor detection sensitivities have been demonstrated by the palpation user study which has showed a direct correlation between tumor size and detection sensitivity and has further proven the efficiency of the proposed actuator and multi-fingered palpation method for tumor detection in palpation simulation.

Pneumatic walking assistive device for use over long period

Humans can adapt to and effectively walk on different kinds of surfaces and in various environments, but fatigue is inevitable when walking or even just standing for long periods, especially when carrying heavy objects. Methods for assisting walking or standing work are in demand, but most research thus far has been focused on using electricity to implement both interlocking and assistive power; this approach has the drawback of high-energy consumption. Therefore, we previously developed a lightweight assistive device that stores part of the kinetic energy generated during the leg swing-to-leg contact phases, and uses this energy to effectively assist during the stance phase. The developed device comprises surge tanks, an air cylinder, and other components arranged in a simple configuration and interlocked with walking by using a simple sensing system, therefore, making it suitable for use over long periods. This paper presents experimental measurements of the assistive force generated using the proposed device when it is attached to human subjects. The measurements were conducted under predicted usages to evaluate the assistive performance of the proposed device, and the measurement results demonstrate its effectiveness.

Sealing components of sowing device of overpressure

Design and operational principles of pneumatic sowing device of overpressure with sealing of seed chamber are described. Process of seed placement into transport channel is researched theoretically. Conditions of secured pushing out of superfluous seeds without jamming and damages are determined. Shape of protuberances of seeding plate is specified.

Лабораторная установка для исследования параметров и режимов работы дискового пневматического высевающего аппарата и результаты проведения лабораторных исследований

Лабораторная установка для исследования параметров и режимов работы дискового пневматического высевающего аппарата и результаты проведения лабораторных исследований

The effect of static muscle forces on the fracture strength of the intact distal radius in vitro in response to simulated forward fall impacts

The distal radius fracture (DRF) is a particularly dominant injury of the wrist, commonly resulting from a forward fall on an outstretched hand. In an attempt to reduce the prevalence, costs, and potential long-term pain/deformities associated with this injury, in vivo and in vitro investigations have sought to classify the kinematics and kinetics of DRFs. In vivo forward fall work has identified a preparatory muscle contraction that occurs in the upper extremity prior to peak impact force. The present investigation constitutes the first attempt to systematically determine the effect of static muscle forces on the fracture threshold of the distal radius in vitro. Paired human cadaveric forearm specimens were divided into two groups, one that had no muscle forces applied (i.e., right arms) and the other that had muscle forces applied to ECU, ECRL, FCU and FCR (i.e., left arms), with magnitudes based on peak muscle forces and in vivo lower bound forward fall activation patterns. The specimens were secured in a custom-built pneumatic impact loading device and subjected to incremental impacts at pre-fracture (25J) and fracture (150 J) levels. Similar fracture forces (6565 (866)N and 8665 (5133)N), impulses (47 (6)Ns and 57 (30)Ns), and energies (152 (38)J and 144 (45)J) were observed for both groups of specimens (p>0.05). Accordingly, it is suggested that, at the magnitudes presently simulated, muscle forces have little effect on the way the distal radius responds to forward fall initiated impact loading.

Retrospective multicentric studying about dynamic orthopedic shoe including a pneumatic anti-footdrop device

Retrospective multicentric studying about dynamic orthopedic shoe including a pneumatic anti-footdrop device

The Effects of Increasing Ocular Surface Stimulation on Blinking and Sensation

The purpose of this study was to determine how increasing ocular surface stimulation affected blinking and sensation, while controlling task concentration. Ten healthy subjects concentrated on a task while a custom pneumatic device generated air flow toward the central cornea. Six flow rates (FRs) were randomly presented three times each and subjects used visual analog scales to record their sensory responses. The interblink interval (IBI) and the FR were recorded simultaneously and the IBI, sensory response, and corresponding FR were determined for each trial. The FR associated with a statistically significant decrease in IBI, the blink increase threshold (BIT), was calculated for each subject. Both the mean and SD of IBI were decreased with increasing stimulation, from 5.69 ± 3.96 seconds at baseline to 1.02 ± 0.37 seconds at maximum stimulation. The average BIT was 129 ± 20 mL/min flow rate with an IBI of 2.33 ± 1.10 seconds (permutation test, P < 0.001). After log transformation, there was a significant linear function between increasing FR and decreasing IBI within each subject (Pearson's r ≤ -0.859, P < 0.05). The IBI was highly correlated with wateriness, discomfort, and cooling ratings (Pearson's r ≤ -0.606, P < 0.001). There was a dose-response-like relationship between increased surface stimulation and blinking in healthy subjects, presumably for protection of the ocular surface. The blink response was highly correlated with ocular surface sensation, which is not surprising given their common origins. The BIT, a novel metric, may provide an additional end point for studies on dry eye or other conditions.

G1010306 筋電位に基づく動作予測を用いた空気圧式腕用パワーアシスト装置の開発([G101-03]機械力学・計測制御一般セッション(3))

Assistive devices can be worn to enhance the wearer's strength. Such devices need to be safe for the wearer Pneumatic actuators are suitable for driving those devices because they are highly safe for humans. However, the responsiveness of pneumatic actuators is lower than that of electric actuators due to the compressibility of air. In this paper, we use the initial burst in muscle activity to avoid delay in activating our pneumatic arm assistive device for the wearer's motion. The initial burst that always occurs first in voluntary movements indicates the wearer's preparation for movement. It is detected based on an inflection point on the cumulative addition curve obtained from a surface electromyogram signal. Experimental verification shows that the activation of the assistive device prior to the wearer's actual movement is possible.

The Clinical Research Office of the Endourological Society Ureteroscopy Global Study: Indications, Complications, and Outcomes in 11,885 Patients

To assess the current indications for ureteroscopy (URS) treatment, outcome in terms of stone-free rate, and intra- and postoperative complications using the modified Clavien grading system. The Clinical Research Office of the Endourological Society collected prospective data as part of the URS Global Study for consecutive patients treated with URS at centers around the world for 1 year. URS was performed according to study protocol and local clinical practice guidelines. The stone size and location were recorded and postoperative outcome and complications, graded according to the modified Clavien grading system, reported. Between January 2010 and October 2012, 11,885 patients received URS at 114 centers in 32 countries; 1852 had only renal stones, 8676 had only ureteral stones, and 1145 patients had both types of stone. Fragmentation was performed principally using a laser device (49.0%) or a pneumatic device (30.3%); no device was used in 17.9% of the patients. A high stone-free rate (85.6%) was achieved. The large majority of patients did not receive any further treatment for renal or ureter stones (89.4%). The postoperative complication rate was low (3.5%). The most frequent complication was fever (1.8%); a blood transfusion was required in 0.2% of patients. The majority of complications were Clavien grade I or II (2.8% of patients). URS is an established minimal invasive treatment for urinary stones with a high success rate and low morbidity. Recent advances have expanded the indication for urinary stones, which now ranges from treatment of smaller sized distal ureter stones by semirigid URS to larger sized renal pelvis stones treated by flexible URS.

Efficiency of a pneumatic device in controlling cuff pressure of polyurethane-cuffed tracheal tubes: a randomized controlled study

BackgroundThe primary objective of this study was to determine the efficiency of a pneumatic device in controlling cuff pressure (Pcuff) in patients intubated with polyurethane-cuffed tracheal tubes. Secondary objectives were to determine the impact of continuous control of Pcuff, and cuff shape on microaspiration of gastric contents.MethodsProspective randomized controlled study. All patients requiring intubation and mechanical ventilation ≥48 h were eligible. The first 32 patients were intubated with tapered polyurethane-cuffed, and the 32 following patients were intubated with cylindrical polyurethane-cuffed tracheal tubes. Patients randomly received 24 h of continuous control of Pcuff using a pneumatic device (Nosten®), and 24 h of routine care of Pcuff using a manometer. Target Pcuff was 25 cmH2O. Pcuff was continuously recorded, and pepsin was quantitatively measured in all tracheal aspirates during these periods.ResultsThe pneumatic device was efficient in controlling Pcuff (med [IQ] 26 [24, 28] vs 22 [20, 28] cmH2O, during continuous control of Pcuff and routine care, respectively; p = 0.017). In addition, percentage of patients with underinflation (31% vs 68%) or overinflation (53% vs 100%) of tracheal cuff, and percentage of time spent with underinflation (0.9 [0, 17] vs 14% [4, 30]) or overinflation (0 [0, 2] vs 32% [9, 54]) were significantly (p < 0.001) reduced during continuous control of Pcuff compared with routine care.No significant difference was found in microaspiration of gastric content between continuous control of Pcuff compared with routine care, or between patients intubated with tapered compared with cylindrical polyurethane-cuffed tracheal tubes.ConclusionThe pneumatic device was efficient in controlling Pcuff in critically ill patients intubated with polyurethane-cuffed tracheal tubes.Trial registrationThe Australian New Zealand Clinical Trials Registry (NCT01351259)

Continuous control of tracheal cuff pressure for the prevention of ventilator-associated pneumonia in critically ill patients

Ventilator-associated pneumonia (VAP) is a major cause of death, morbidity and costs in ICUs. Several evidence-based clinical interventions have been increasingly described for its prevention. However, continuous control of tracheal cuff pressure (Pcuff) is rarely mentioned in the latest clinical guidelines. This review focuses on the available data about the management of Pcuff in the ICU, including discontinuous and continuous control, and its impact on the prevention of VAP. Current discontinuous monitoring and adjustment of Pcuff, even well performed, is inaccurate in maintaining Pcuff in the target range. Underinflation (Pcuff<20 cmH2O) of tracheal cuff is an independent risk factor for VAP through microaspiration of contaminated subglottic secretions into the lower respiratory tract. Two main types of devices, electronic and pneumatic, have been developed for the continuous control of Pcuff. Both have shown effectiveness in maintaining Pcuff in recommended range in ICU patients, but only the pneumatic device has provided a reduction in microaspiration and VAP incidence. Continuous controllers of Pcuff represent effective, easy to use and timesaving devices in today's busy ICU environment. However, further studies are required to determine the impact of continuous control of Pcuff on VAP incidence, patient outcomes, antimicrobial consumption and to compare pneumatic and electronic devices, before generalizing their use in routine practice.

Responses of human hip abductor muscles to lateral balance perturbations during walking

Lateral stability during gait is of utmost importance to maintain balance. This was studied on human subjects walking on a treadmill who were given 100-ms perturbations of known magnitude and timing with respect to the gait cycle by means of a computer-controlled pneumatic device. This method has the advantage that the same perturbations can be given at different phases of the stride cycle, thereby allowing an analysis of the phase dependency of the responses in the primary muscles involved. After an inward push, e.g., a push toward the left during right stance, the left foot in the step to follow is placed more to the left (outward strategy). The hypothesis was that this movement is caused by automatic unvoluntary muscle activity. This turned out to be the case: the abduction movement follows EMG responses in the left abductor muscle, gluteus medius, in response to the push. Two responses, with latencies of 100 and 170ms, and a late reaction >270ms can be discerned. All three responses are phase dependent; they show facilitation in swing and no response in stance, in contrast to the normal walking activity (background). This independence of the background activity suggests a premotoneuronal gating of these responses, reminiscent of phase-dependent modulation of electrically elicited reflexes. It is concluded that facilitating pathways are opened independent of normal background activation to enable appropriate actions to restore balance after a mediolateral perturbation.

Novel Pneumatic Device for High Speed Needle Insertion in Brachytherapy

Novel Pneumatic Device for High Speed Needle Insertion in Brachytherapy

Continuous control of tracheal cuff pressure and ventilator-associated pneumonia

Intubation is performed in a large proportion of critically ill patients. Underinflation (< 20 cmH2O) and overinflation (> 30 cmH2O) of tracheal cuff were identified as risk factors for microaspiration and tracheal ischemic lesions, respectively. Maintaining cuff pressure (Pcuff) around 25 cmH2O is recommended to prevent these complications. Periodic adjustment of Pcuff using a manual manometer might be helpful in preventing severe tracheal ischemic lesions. However, despite manual control of Pcuff, patients spend a large amount of time with underinflation of Pcuff. Two randomized controlled studies evaluated the impact of continuous control of Pcuff on microaspiration of gastric contents and ventilation-acquired pneumonia (VAP) incidence. The first study using an electronic device failed to demonstrate any impact of continuous control of Pcuff on VAP rate (15% in the two groups). However, the second one found the pneumatic device to be associated with significantly reduced microaspiration of gastric contents, tracheobronchial colonization, and VAP rate (9.8% vs. 26.2%, p = 0.032, odds ratio [95%confidence interval] 0.30 [0.11–0.84]). Different devices and different patient characteristics might explain the different results found in these studies. Further randomized controlled multicenter trials are needed to determine the impact of continuous control of Pcuff on VAP incidence, and to compare the different available devices.

Robotic assessment of the influence of age on upper-limb sensorimotor function

PurposeThis paper examines the influence of age on several attributes of sensorimotor performance while performing a reaching task. Our hypothesis, based on previous studies, is that aged persons will show differences in one or more of the attributes of sensorimotor performance.Patients and methodsFifty-one subjects (aged 20–80 years) with no known neuromotor disorders of the upper limbs participated in the study. Subjects were asked to grasp the end-effector of a pneumatic robotic device with two degrees of freedom in order to reach peripheral targets (1.0 cm radius), “quickly and accurately”, from a centrally located target (1.0 cm radius). Subjects began each trial by holding the hand within the central target for 2000 milliseconds. Afterwards, a peripheral target was illuminated. Then participants were given 3000 milliseconds to complete the movement. When a target was reached, the participant had to return to the central target in order to start a new trial. A total of 64 trials were completed and each peripheral target was illuminated in a random block design.ResultsSubjects were divided into three groups according to age: group 1 (age 20–40 years), group 2 (age 41–60 years), and group 3 (age 61–80 years). The Kruskal–Wallis test showed significant differences (P < 0.05) between groups, except for the variables postural speed in the dominant arm, and postural speed and initial deviation in the non-dominant arm (P > 0.05). These results suggest that age introduces significant differences in upper-limb motor function.ConclusionOur findings show that there are objective differences in sensorimotor function due to age, and that these differences are greater for the dominant arm. Therefore for the assessment of upper-limb function, we should take into account the influence of age. Moreover, these results suggest that robotic systems can provide a new and effective approach in the assessment of sensorimotor function.