Pneumatic Source Research Articles

Numerical Investigation of Geometric Factors for Design of High Performance Air-Jet Pumps Using in Vehicle-Mounted Vacuum Toilet

Air-jet pump as the pneumatic source of a vehicle-mounted vacuum toilet provides the vacuum to pump the fecal sewage out of toilet bowl via the compressed air passing through the pump under certain pressure. In this study, Computational Fluid Dynamics (CFD) technique is employed to investigate the effects of three important air-jet pump geometry parameters: the primary Nozzle Exit Position (NXP), the constant-area section length (L1) and the diffuser diverging angle (θ), on its performance. A CFD model is firstly established according to 1D analytical method, and then used to create 135 different air-jet pump geometries and tested under different operating conditions. The significance of this study is that these findings can be used to guide the adjustment of NXP, L1 and θ to obtain the best air-jet pump performance when the operating conditions are different.

Prospects of development of autonomous pneumatic vehicles

The contemporary state, prospects of development, and application of vehicles using energy of compressed air are analyzed. Potential marginal valuations of the efficiency of a pneumatic power source and piston pneumatic motor are obtained. The possibility of brake energy regeneration for subsequent acceleration is presented.

Development and testing of a novel portable pneumatic power source using phase transition at the triple point

This study is concerned with the development of a novel portable pneumatic power source applicable to wearable robots, pneumatically operated tools, and other pneumatic devices. Dry ice was chosen as the source of power because it is non-poisonous, inexpensive, and it expands to 750 times its volume after it sublimes into gas. When dry ice fills a confined pressure container, it sublimes and then liquefies after the pressure reaches the triple point of CO2 (0.52 MPa (abs), −56.6 °C). As long as dry ice remains at the triple point state in which all three phases coexist in equilibrium, the pressure remains constant and does not decrease even though the gas is released at a high rate of flow. In this study, by controlling the heat transfer between the pressure container and the ambient atmosphere, a novel pneumatic power source, which always stores dry ice in a state near its triple point, was developed. It has a constant output pressure of 0.42 MPa and is quiet, light, and safe, and produces a large capacity of pneumatic flow. Most significantly, the device does not require a large amount of operation power because it uses saved latent heat.

Preliminary Flight Tests of a Hinge-Less Roll Control Effecter

Introduction T HERE has been a growing research effort to achieve effective hinge-less flight control, spurred on by advances in fluidic control. For purposes of stealth, reduced vehicle weight, increased robustness and damage tolerance as well as compactness, hinge-less methodology is extremely attractive. Hinge-less control can be implemented through either continuous or oscillatory flow manipulation. Continuous manipulation can be achieved using blowing. Past research efforts have shown jet flaps1,2 and circulation control3,4 to be effective at augmenting lift and varying pitching moment. A recent study has shown that a highly deflected (normal to the surface) jet flap can match the performance of a Gurney flap using moderate jet momentum coefficients.5 However, continuous blowing invariably requires drawing air off the engine’s compressor or using shaft power to drive a compressor. Ducting is also required to route the air through its ejection path. Consequently, weight and thrust penalties can be incurred. It would be advantageous to the designer to have the flexibility to employ a modular air-injection system that can be placed locally where control is required. The system can be configured to function as a jet flap or used for augmenting existing control effecters (forming a blown flap). Such a system would have the advantage of not requiring pneumatic lines and can be employed in flight vehicles where a pneumatic source is not present (e.g., unmanned aerial vehicles). In this Note we detail the design and implementation of a self-contained modular blower system. Blower design details are elucidated, as are verification of the blower’s effectiveness as a roll control device through flight testing.

The acoustic fields of shock wave therapy devices

We report measurements of a number of different shock wave therapy (SWT) devices. Two devices were electrohydraulic (EH): one had a large shock source (HMT Ossatron) and the other was a small hand-held source (HMT Evotron). The other device was a pneumatically driven device (EMS Swiss Dolorclast) and two different hand pieces were measured, one with an ‘‘unfocused’’ head and the other with a ‘‘focused’’ head. We found that the EH sources generated focused shock waves with a positive phase about 1 microsec long and peak pressure around 40 MPa, however, the acoustic output of the HMT Evotron appeared to be independent of the power setting of the machine. For the pneumatic source the duration of the positive phase was greater than 4 microsec and the peak pressure about 7 MPa. There was no clear shock front present and the waveform had a complex tail structure that was dependent on the power setting of the machine. We found that the focused hand-piece did not generate a focused acoustic field. The results are compared to reports of measurements from electromagnetic SWT devices. We contrast measurements made with different hydrophone systems: fiber-optic probe hydrophone, PVDF membrane hydrophone and PVDF bullet-shaped hydrophone.

三重点における相変化を利用した携帯空圧源の開発

三重点における相変化を利用した携帯空圧源の開発

Church-Sect Dynamics and the Feast of Corpus Christi

Close systematic analysis of interaction episodes depicted in the vita of a thirteenth-century religious virtuosa reveals the basic social elements connecting charismatic agency to a contingent structural moment in the medieval ecclesia. During the contingency phase a dynamic human network drawn from small ruling circles assumed sect-like characteristics to incorporate the special charismatic gifts of Juliana Mont-Cornillon, who provided the unifying symbol in their human quest for legitimate domination and control. The case analysis illustrates contemporary theorizing in church-sect typologies by describing the dynamic micro-processes of a religious movement and negotiations for power behind the illusory veneer of a univocal institutional church. These processes resulted in an integration of the new Feast of Corpus Christi, which simultaneously recognized, incorporated, and quarantined the pneumatic source and feminine voice of Juliana

Acoustic and cavitation fields produced by shock wave therapy (SWT) devices with different generating principles

We present measurements from two SWT devices with different generating principles: an electrohydraulic source (EHS) with a focusing reflector (HMT Equitron) and a pneumatic source (PS) with no focusing (EMS Swiss Dolorclast). The acoustic field was measured with a PVDF membrane hydrophone. For the EHS the focal waveform consisted of a shock wave with a short compressive pulse lasting 1 μs (rise time less than 50 ns) and a negative tail of 1.5 μm. The average peak positive pressure at the focus was 20 MPa and showed little variation with energy level. The waveform from the PS had a compressive phase of 2-μm-duration (rise time 1 μs) followed by a complex negative phase of 4-μs duration. The peak positive pressure increased from 2 to 8 MPa with increasing energy setting. A passive cavitation detection (PCD) system was used to monitor the cavitation activity produced by the two devices. The EHS produced measurable cavitation with a life time that varied between 110 to 140 μs. We were unable to detect cavitation from the PS. These data indicate that the two devices studied here have different physical characteristics and this may affect the processes by which they operate clinically.

Interface wave generated by an electromagnetic induction source

Interface waves such as the Scholte wave are a useful tool to study geoacoustic properties and can be conventionally generated by an explosive or a pneumatic source on/above the seafloor. This type of source, however, generates strong compressional waves in the water and sediment at the same time; these waves then disturb an observation of interface waves and leads to difficulty in processing. These sources are also relatively hard to control at sea from a viewpoint of repeatability and stability of interface waves to be generated. In addition, environmental problems caused by those sources is a concern. In this paper, an electromagnetic induction source whose vibrator plate hits the seafloor directly and excites interface waves is described. The capability of this source was evaluated both in a water tank and at seashore. The pulsed Scholte waves excited both by several types of electromagnetic induction source having a different shape of vibrator plate and by dropping weight were transmitted in sediment and received using geophones. As a result of comparison of measured signals, the pulse signal propagating from the source demonstrates a sharper rise time than that from dropping weight.

Versatile one-piece total artificial heart for bridge to transplantation or permanent heart replacement.

A versatile, one-piece total artificial heart (TAH) system that can be driven by either an electromechanical acutator (EM-TAH) or a pneumatic source (P-TAH) has been developed. The common units for both TAHs are the conically shaped left and right pusher-plate-type pumps (63 ml SV) that sandwich a thin centerpiece (18 mm) having a respective actuator. The EM actuator, mounted in the middle of the centerpiece, consists of a direct-current brushless motor and a roller screw while the pneumatic actuator consists of a low-pressure air source. The outer diameter of the pumping unit is 97 mm with its central thickness being 82 mm; overall volume is 510 cc. The TAH is operated in the left master alternative ejection mode with the left pump fill signal. High-flex-life Hexsyn rubber is used as the diaphragm, and the blood-contacting surface is coated with dry gelatin. The TAH can provide 3-8 L/min flow with a preload of 1-10 mm Hg against 100 mm Hg afterload. Anatomical fit of the pumping unit has been demonstrated in the pericardial space of 26 heart transplant recipients with average body weight of 78 kg. To date, 2 P-TAH and 4 EM-TAH (1 week) implantations were performed in 80-100 kg calves demonstrating excellent anatomical fit, controllability, and biocompatibility. This versatile TAH is suitable for a bridge to transplantation or permanent heart replacement.

Determining the parameters of the working cycle of a pneumatic vibration source with reverse-rotary motion of the unbalanced mass

Determining the parameters of the working cycle of a pneumatic vibration source with reverse-rotary motion of the unbalanced mass

Evaluation of P- and S-wave sources for shallow seismic reflection

The theoretical attractiveness of utilising both P- and S-reflection information is offset in the shallow environment by the practical difficulty of isolating high resolution reflections from other non-reflection energy. Source design is a critical component in a range of mandatory acquisition and processing optimisations. Four near-surface P-wave sources (high explosive, shotgun, weight drop, and hammer) have been evaluated in terms of their suitability for shallow reflection at a test site in the Ipswich Basin, southeast Queensland. Cross power spectral analyses of trace segments in the reflection window provide an estimate of the ‘coherent bandwidth’ of the different sources. Although the high explosive has superior signal levels, consideration of spectral symmetry, autocorrelation shape, and logistic aspects indicates that the shotgun source is a viable alternative. A pneumatic powered S-wave generator has been constructed and tested. Integrated spectral energies have been used to monitor piston velocity limitations and hence define optimum operating parameters. The pneumatic source is more controllable and of higher energy than a sledgehammer-powered equivalent.

Device for producing soundwaves in water

An apparatus for producing acoustic waves in water through sudden ejection of liquid mass from a tubular main housing. A first shuttle and second shuttle are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber for confining therein a liquid slug. A pneumatic source together with a pneumatically-operated valve cyclically cause the shuttles to move relative to or in locked condition with each other, thereby applying during each cycle of operation an abrupt propulsion force to the confined liquid slug which becomes expelled as a very high-velocity liquid jet through ports in the housing. A calibrated control element for providing the proper pressures to the pneumatically-operated valve ensures proper movement of the shuttles.

A dynamic model of pneumatic vibration source of an impact-rotary action

A dynamic model of pneumatic vibration source of an impact-rotary action

The Design of a Pneumatic Pressure Reference Source with Automatic Control

The design of a pneumatic pressure reference source with automatic control is described. The design is based on the accuracy and reliability of the well known dead weight tester and a piston position transducer is incorporated with a precision pressure controller to form a closed loop system. A linearised analysis is used to show the complexity of the system dynamics and give some indication of the stability criteria. A prototype model was built, tested and the results are discussed. Conclusions are drawn that suggest the system is feasible and worthy of further development.

Prevention of deep-vein thrombosis due to stasis.

Deep-vein thrombosis due to stasis in the lower extremities commonly occurs in surgery or during prolonged periods of bed rest. A system to prevent stasis was developed and consists of a three-compartment pressure cuff, a pneumatic source, and an electronic controller. The cuff is designed to be placed on the lower extremities over the calf. Each section of the cuff is sequentially and intermittently compressed. The sequential action for this compression is developed by an electronic controller that regulates pressure, periodicity, and duration of compression. Results show that a pressure wave can be developed that squeezes and propels the blood anteriorly through the venous system, and when the pressure is released the venous system refills.

A PNEUMATIC SEISMIC ENERGY SOURCE FOR SHALLOW WATER / MARSH AREAS*

AbstractNon dynamite seismic energy sources have shown only limited success in difficult shallow‐water or marsh prospect areas, and none have applicability to both environments. Recently, a method has been devised to adapt a marine pneumatic source for operation in abrasive surroundings. A system composed of four of these modified sources together with associated emplacement and retrieval mechanisms has been developed and has proven to be a reliable and efficient seismic energy source for both shallow‐water and marsh applications.

PNEUMATIC ACOUSTIC ENERGY SOURCE*

ABSTRACTIn recent years considerable work has been done to devise a satisfactory non‐dynamite seismic system that would replace dynamite in offshore areas. Prior to the advent of digital recording and processing, the non‐dynamite sources have generally not provided the depth of penetration or the resolution required for satisfactory seismic interpretation.More recent developments in non‐dynamite offshore marine sources include adaptation of the Vibroseis from a land unit to a marine unit, and adaptation of the Dinoseis unit from a land to a marine unit. The SUE (Seismic Underwater Explorer) system is a thermodynamic non‐dynamite source utilizing a mixture of propane and oxygen detonated in a special chamber approximately 15 feet below the water surface. This source gives penetration to more than 4 sec in areas typified by Gulf of Mexico type geology and shows deeper penetration than had previously been obtained by dynamite along the western United States in areas with 20 lb charge limitations. A pneumatic source, the airgun, has been in production use in the United States since June 1966. This non‐dynamite source provides an intriguing amount of versatility and can be expanded to provide additional energy as necessary to obtain the penetration desired. Tests using systems comprised of from eight to twenty‐three airguns show penetration in excess of 5 seconds in many areas. Power spectra comparisons both in amplitude and frequency content demonstrate that this is a controlled source generating a controlled seismic wavelet and a controlled frequency spectrum that can be tailored to fit requirements of particular areas. Sample sections obtained in the Gulf of Mexico and the Pacific Ocean offshore California show adequate penetration to 5.0 seconds reflection time.Quantitative measurements with the airguns demonstrate the effect of: Variation of the number of guns in the system; Shaping the frequency spectrum by using different sizes of airguns in the system; Effects on signal‐to‐noise ratios as a result of stacking several small energy sources together; Reproducibility of the initial pulse wavelet from shot to shot. The improvement in record quality as a result of advanced digital processing with non‐dynamite sources is comparable to that obtained with dynamite sources. Non‐dynamite sources make additional improvements possible where high source multiplicity is advantageous. Excellent dynamic correlations yield accurate velocity control as well as definitions of apparent velocities attributable to multiples and primary‐to‐multiple amplitude relationships.Non‐dynamite sources are being used more and more extensively in offshore exploration. The advent of digital recording and processing provides a means for improving depth of penetration and resolution of many non‐dynamite sources.

Auxiliary Equipment

A miniature gas turbine that delivers cither 5 or 10 h.p. has been announced by Propulsion Research Corporation, Santa Monica, California, a subsidiary of Curtiss‐Wright Corporation. This engine weighs only 30 lb. and can be used as an auxiliary power unit, portable pump, portable pneumatic source or portable ground power.