Artykuły w czasopismach: „Pressure Wave Generator (PWG)”

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Li, Xinzhong, Litao Chen, Zhengpeng Wang, Ke Yang i Jungang Miao. "An Ultra-Wideband Plane Wave Generator for 5G Base Station Antenna Measurement". Electronics 12, nr 8 (12.04.2023): 1824. http://dx.doi.org/10.3390/electronics12081824.

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Plane-wave generators (PWGs) for over-the-air testing of 5G base stations offer the advantages of efficiency and economy. Many new bands, such as n28, are progressively being introduced, driving the bandwidth improvement of PWGs. The cost of amplitude–phase control networks is also increased by the broadband range required for testing. In view of the above challenges, in this paper, a low-frequency ultra-wideband PWG for testing 5G base stations is reported. Firstly, an electrically small antenna unit based on the Vivaldi antenna is design for the PWG. The antenna unit has a wide operating band and compact size, allowing it to reach a quarter of the minimum frequency wavelength. Then, the operating band from 700 MHz to 4 GHz is divided into three sub-bands, and the amplitude and phase excitations within each sub-band are optimized with multiple frequency points. Finally, the designed ultra-wideband PWG is simulated and experimentally tested. The designed 2.64 m one-dimensional linear-array PWG is able to produce a 1.5 m × 1.32 m quiet zone with less than 1.0 dB and 10°. The results of the radiation pattern measurements for the base station agree reasonably well with the MVG SG128.

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Wang, Sheng Hung, Lee Long Han i Tsing Tshih Tsung. "Dynamic Pressure Calibration of Pressure Sensors Using Liquid Step Pressure Generator". Key Engineering Materials 437 (maj 2010): 8–12. http://dx.doi.org/10.4028/www.scientific.net/kem.437.8.

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. This study presents the dynamic calibration of pressure sensors using a developed liquid step wave generator. This approach is sufficient to display the transient response of pressure sensors in the time and frequency domains and it depends on the performance of pressure generators. In this study, the liquid step wave generator was developed via a reformed spool valve generating a liquid step wave with a short rise time that current generators have not achieved so far. A small sensing cavity, where maintains the liquid step wave, and a contact seal were adopted herein to limit the pressure transient of the fluid in the generator, such that the rise time and the bandwidth of the liquid step wave can reach 30.0 µs and 10.4 kHz. The experimental results not only display the performance of the liquid step wave generator, but also reveal the dynamic characteristics of three different test pressure sensors using the developed liquid step wave generator.

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Jahed, M., i S. J. Lai-Fook. "Stress wave velocity measured in intact pig lungs with cross-spectral analysis". Journal of Applied Physiology 76, nr 2 (1.02.1994): 565–71. http://dx.doi.org/10.1152/jappl.1994.76.2.565.

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In anesthetized pigs (25–40 kg), we generated stress waves in the lung by rapid deflation of an esophageal balloon. The source distortion was measured by an accelerometer (1 g wt) bonded to the balloon. Stress waves were detected by three accelerometers bonded to intercostal muscle and to the skin near midchest. The distance between the source and chest receivers were measured radiographically. Cross-spectral analysis was used to calculate transit times. We measured stress wave velocities at airway pressures of 0 (functional residual capacity) and 25 cmH2O. Transpulmonary pressure (Ptp) was measured by an esophageal balloon. In vivo, stress wave velocities increased from 291 +/- 117 (SD) cm/s at 3.0 +/- 0.9 cmH2O Ptp to 573 +/- 73 cm/s at 13.8 +/- 3.5 cmH2O Ptp (n = 6). These velocities agreed with longitudinal wave velocities measured in isolated sheep lungs and predictions based on the elastic moduli of lung parenchyma. Post-mortem edema was induced by intratracheal instillation of 200 ml of saline, resulting in a wet-to-dry weight ratio of 7.7 +/- 1.4 (n = 5). At 15 cmH2O Ptp, stress wave velocities decreased from 565 +/- 155 cm/s before edema to 445 +/- 130 cm/s after edema. This decrease correlated well with predictions based on the increased lung density, as dictated by elasticity theory.

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Donnelly, Graeme, Timothy D. Jackson, Krista Ambrous, Jing Ye, Adeel Safdar, Laura Farraway i Jan D. Huizinga. "The myogenic component in distention-induced peristalsis in the guinea pig small intestine". American Journal of Physiology-Gastrointestinal and Liver Physiology 280, nr 3 (1.03.2001): G491—G500. http://dx.doi.org/10.1152/ajpgi.2001.280.3.g491.

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In an in vitro model for distention-induced peristalsis in the guinea pig small intestine, the electrical activity, intraluminal pressure, and outflow of contents were studied simultaneously to search for evidence of myogenic control activity. Intraluminal distention induced periods of nifedipine-sensitive slow wave activity with superimposed action potentials, alternating with periods of quiescence. Slow waves and associated high intraluminal pressure transients propagated aborally, causing outflow of content. In the proximal small intestine, a frequency gradient of distention-induced slow waves was observed, with a frequency of 19 cycles/min in the first 1 cm and 11 cycles/min 10 cm distally. Intracellular recording revealed that the guinea pig small intestinal musculature, in response to carbachol, generated slow waves with superimposed action potentials, both sensitive to nifedipine. These slow waves also exhibited a frequency gradient. In addition, distention and cholinergic stimulation induced high-frequency membrane potential oscillations (∼55 cycles/min) that were not associated with distention-induced peristalsis. Continuous distention produced excitation of the musculature, in part neurally mediated, that resulted in periodic occurrence of bursts of distally propagating nifedipine-sensitive slow waves with superimposed action potentials associated with propagating intraluminal pressure waves that caused pulsatile outflow of content at the slow wave frequency.

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Marlinghaus, Ernst H., Othmar J. Wess i Josef Katona. "A NEW PRESSURE WAVE GENERATOR FOR EXTRACORPOREAL LITHOTRIPSY". Biomedizinische Technik/Biomedical Engineering 35, s3 (1990): 235–36. http://dx.doi.org/10.1515/bmte.1990.35.s3.235.

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Tsung, Tsing Tshih, Lee Long Han, Liang Chia Chen i Ho Chang. "Performance Characterization of Pressure Sensors Using an Improved Pressure Square Wave Generator". Key Engineering Materials 295-296 (październik 2005): 533–38. http://dx.doi.org/10.4028/www.scientific.net/kem.295-296.533.

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The purpose of this paper is to analyze and compare the dynamic characteristics of various structure pressure sensors using the Improved Pressure Square Wave Generator (IPSWG). The developed IPSWG is a signal generator that creates pressure square waves as an excitation source. The dynamic characteristics of pressure sensor in hydraulic systems can be measured and evaluated effectively due to the high excitation energy. The method is also useful for dynamic testing and characterization for a high frequency range, which cannot be performed by the traditional methods, such as the hammer kit excitation, sweeping frequency pressure wave, and random frequency wave. Result shows that piezoelectric sensors (quartz) have a largest gain margin and overshoot. The strain gauge sensor has a smaller gain margin and overshoot. The piezoelectric sensor is more suitable for measuring dynamic pressure.

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Tsung, T. T., S. H. Wang i L. L. Han. "The Measurement and Analysis of Pressure Square Wave Generator". Journal of Physics: Conference Series 48 (1.10.2006): 616–19. http://dx.doi.org/10.1088/1742-6596/48/1/115.

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Kobata, T., i A. Ooiwa. "Square-wave pressure generator using a novel rotating valve". Metrologia 36, nr 6 (grudzień 1999): 637–40. http://dx.doi.org/10.1088/0026-1394/36/6/30.

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Vicinanza, D., i P. Frigaard. "Wave pressure acting on a seawave slot-cone generator". Coastal Engineering 55, nr 6 (czerwiec 2008): 553–68. http://dx.doi.org/10.1016/j.coastaleng.2008.02.011.

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Morales, J., M. Garcia, C. Perez, J. V. Valverde, C. Lopez-Sanchez, V. Garcia-Martinez i J. L. Quesada. "Low frequency electromagnetic radiation and hearing". Journal of Laryngology & Otology 123, nr 11 (2.07.2009): 1204–11. http://dx.doi.org/10.1017/s0022215109005684.

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AbstractObjective:To analyse the possible impact of low and extremely low frequency electromagnetic fields on the outer hairs cells of the organ of Corti, in a guinea pig model.Materials and methods:Electromagnetic fields of 50, 500, 1000, 2000, 4000 and 5000 Hz frequencies and 1.5 µT intensity were generated using a transverse electromagnetic wave guide. Guinea pigs of both sexes, weighing 100–150 g, were used, with no abnormalities on general and otic examination. Total exposure times were: 360 hours for 50, 500 and 1000 Hz; 3300 hours for 2000 Hz; 4820 hours for 4000 Hz; and 6420 hours for 5000 Hz. One control animal was used in each frequency group. The parameters measured by electric response audiometer included: hearing level; waves I–IV latencies; wave I–III interpeak latency; and percentage appearance of waves I–III at 90 and 50 dB sound pressure level intensity.Results:Values for the above parameters did not differ significantly, comparing the control animal and the rest of each group. In addition, no significant differences were found between our findings and those of previous studies of normal guinea pigs.Conclusion:Prolonged exposure to electromagnetic fields of 50 Hz to 5 KHz frequencies and 1.5 µT intensity, produced no functional or morphological alteration in the outer hair cells of the guinea pig organ of Corti.

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Wang, Sheng Hung, Lee Long Han i Tsing Tshih Tsung. "Hydraulic Pressure Wave Generator for Performing the Calibration of Hydraulic Components". Key Engineering Materials 381-382 (czerwiec 2008): 125–28. http://dx.doi.org/10.4028/www.scientific.net/kem.381-382.125.

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One hydraulic pressure generator has been developed with a unique rotating valve and the waveform of generated waves is approximately square-like shape under the low rotating speed. The generated wave has advantages for research in the dynamic characteristics of hydraulic components. The unique rotating valve consists of a rotor and stator which have a number of rectangle grooves precisely milled on the peripheries of the rotor and stator as fluid channels. The rotating rotor alternately switches the fluid channels to open and close state, therefore the waveform is close to square in principle. The pressure transient on the generated wave plays a major role and influences dynamic performances of generated wave. For analyzing the performances of the generator, one sensitivity pressure transducer mounted on the outlet of the generator to measure waveform in time domain. In addition, through Fourier series expansion the spectrum of generated waves clearly indicates the harmonic components of generated waves. Results show the waveform is close to square-like under the low rotating speed in time domain. In the frequency domain, the spectrum of the generated wave demonstrates the bandwidth is abundant. Thus, the generator could be one kind of function generator to performing the calibration of the hydraulic components.

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Chang, Ho, Mu Jung Kao, Tsing Tshih Tsung i J. L. Wu. "An Innovative Technology for Measuring The Dynamic Characteristics of Pressure Sensors". Materials Science Forum 505-507 (styczeń 2006): 1057–62. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.1057.

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This study developed a square-like pressure wave generator as an excitation source to test dynamic characteristics of pressure sensors. The developed generator can generate a square-like pressure wave of as high as 2 kHz and can achieve high-frequency switching by utilizing the differential principle through a series of mechanical rotations between the revolving spindle and revolving ring. The square-like pressure wave generated is input into the hydraulic system while the output voltage signals given by the pressure sensor can be analyzed by spectrum analysis to obtain dynamic characteristics of the pressure sensor

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Ding, Chuan, Yu Huang, Haoqi Chen, Lichao Zhang, Bin Meng i Yuanhao Gao. "New Hydraulic High-Pressure Impulse Generator for Long-Duration Impulse Tests". Applied Sciences 11, nr 3 (20.01.2021): 901. http://dx.doi.org/10.3390/app11030901.

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Water hammer wave is widely applied to test hydraulic components in various areas. A new hydraulic high-pressure impulse generator is presented in this paper in order to provide the standard water hammer wave for long-term usage. A combination of a sleeve and a rotary spool was used to build the impulse generator, and a booster piston was applied to amplify the output pressure. Mathematical models were established using commercial software, and a prototype and a test rig were built based on the simulation results. The experimental results for both single wave and repeated periods show the feasibility of the new design and indicate that the new hydraulic high-pressure impulse generator can be used for long-time impulse tests.

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Wang, S. H., T. T. Tsung i L. L. Han. "Hydraulic square-wave pressure generator with a specific rotating valve". Measurement 42, nr 5 (czerwiec 2009): 672–77. http://dx.doi.org/10.1016/j.measurement.2008.11.003.

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Tsung, Tsing-Tshih, i Lee-Long Han. "Evaluation of dynamic performance of pressure sensors using a pressure square-like wave generator". Measurement Science and Technology 15, nr 6 (14.05.2004): 1133–39. http://dx.doi.org/10.1088/0957-0233/15/6/013.

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Choi, Hoomi, i Tae Sung Kim. "Numerical Simulation of Ultrasonic Generator in Dust Removing System". Advanced Materials Research 488-489 (marzec 2012): 1446–50. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.1446.

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An ultrasonic dry cleaning system is a kind of air-blowing cleaning system, which clears away fine particles of dust adhering to a surface. This system does not require high cost consumables such as highly pure gases or chemical solvents. Moreover it removes micro contaminant particles without additional cooling or heating processes. In this paper, a numerical simulation of the ultrasonic dry cleaning system was carried out to propose an optimum ultrasonic generator. We evaluated the flow in the chamber according to the groove shape of ultrasonic generator, and system operating pressure using a commercial fluid dynamic simulation tool. And the trend of the sound pressure level (SPL) according to frequency was checked to determine whether or not the ultrasonic generator module could generate an ultrasonic wave. The particle trajectories were compared for several conditions and particle sizes. We confirmed that an ultrasonic wave of sufficient flow velocity can be generated through the ultrasonic generator module. And the changes of SPL according to the system operating pressure and the shape of the ultrasonic generator groove were confirmed respectively.

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TOSHIRO, Masahito, Hideo UTSUNO, Hiroshi MATSUHISA, Keisuke YAMADA i Katsutoshi SAWADA. "917 Development of a Pressure Wave Generator in an Elastic Pipe". Proceedings of Conference of Kansai Branch 2011.86 (2011): _9–17_. http://dx.doi.org/10.1299/jsmekansai.2011.86._9-17_.

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Sugita, H., Y. Matsubara, A. Kushino, T. Ohnishi, H. Kobayashi i W. Dai. "Experimental study on thermally actuated pressure wave generator for space cryocooler". Cryogenics 44, nr 6-8 (czerwiec 2004): 431–37. http://dx.doi.org/10.1016/j.cryogenics.2004.02.014.

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LIANG, SHEN-MIN, KIET-HOUNG CHOW, IOANNIS MANOUSAKAS, YONG-REN PU i CHIEN-CHEN CHANG. "DESIGN AND FABRICATION OF A SHOCK WAVE GENERATOR FOR MUSCULOSKELETAL DISORDERS". Biomedical Engineering: Applications, Basis and Communications 18, nr 01 (25.02.2006): 24–29. http://dx.doi.org/10.4015/s1016237206000063.

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In the past ten years, extracorporeal shock waves have been successfully used in orthopedics. The idea of shock wave therapy is the stimulation of a healing process. Electrohydraulic shock wave therapy provides higher energy density flux than electromagnetic and piezoelectric types. But electrohydraulic shock wave generators are less stable than the other two types because of electrode erosion. In this study, a shock wave generator with a controllable spark gap system has been designed in order to give steady output pressures by automatic adjustment of the electrode gap. An ellipsoidal shock wave reflector is equipped with two AC servo motors with drivers. The motor driver actuates the associated motor which is connected to an electrode base by a belt. On a designed image feedback system, a CCD camera is used as the image detection tool to measure the electrode gap. Experimental results show the coincidence of the second focus of the shock wave reflector with the gas-dynamic focus. Moreover, measurements of focused pressure and energy intensity with PCB and PVDF pressure sensors and tests of stone fragmentation efficiency have been carried out to evaluate the performance of the newly designed shock wave generator with a gap-adjusted system and an image feedback system. It is found that the designed electrohydraulic shock wave generator is stable and efficient in pressure output with a low cost of electrodes.

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IMRE, ATTILA R., GÁBOR HÁZI i ALEXEY BESOV. "NEGATIVE PRESSURE TAIL OF A REFLECTED PRESSURE PULSE: COMPARISON OF A LATTICE BOLTZMANN STUDY TO THE EXPERIMENTAL RESULTS". International Journal of Modern Physics C 14, nr 10 (grudzień 2003): 1321–30. http://dx.doi.org/10.1142/s0129183103005455.

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A numerical pressure wave reflection experiment in a two-dimensional liquid and its comparison with experimental results are presented. The liquid is simulated by the pseudo-potential extension of the lattice-Boltzmann method. In the simulation a pressure pulse is produced by a point source and the resulting pressure wave is reflected back by a wettable rigid wall. Negative pressure tail can be observed at the vicinity of the wall/liquid interface. The resulted shape of the positive and the negative pressure wave is compared with experimental results obtained in an electromagnetic shock-wave generator. Good agreement has been found between the experimental and simulation results.

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Schulze-Delrieu, Konrad. "Visual parameters define the phase and the load of contractions in isolated guinea pig ileum". American Journal of Physiology-Gastrointestinal and Liver Physiology 276, nr 6 (1.06.1999): G1417—G1424. http://dx.doi.org/10.1152/ajpgi.1999.276.6.g1417.

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How the movements of the intestinal walls relate to luminal pressures and outflow remains incompletely understood. We triggered the peristaltic reflex in the isolated ileum of the guinea pig and quantified wall movements through computerized measurements of diameter changes. Contractions developed as indentations close to the upstream end of the loop. The indentations deepened and expanded in length. The downstream shoulder of contractions started and stopped to propagate before the upstream shoulder. Shoulders differed in their length and gradient over most of the duration of the contraction, and this gives the contraction an axial asymmetry. Over the course of individual contractions, the length of the indented segment correlated well with the luminal pressure. Contractions in response to large volumes generated long indented segments and high luminal pressures. The onset and the end of pressure waves and of outflow did not necessarily coincide with the onset and end of visual parameters of contractions. These findings indicate that objective visual parameters might be useful to describe and to classify contractions.

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Koothirezhi, Rupa, Pratibha Anne, Ugorji Okorie, Minh Tam Ho, Brittany Monceaux, Cesar Liendo i Oleg Chernyshev. "828 Challenges of artifact in Polysomnography-An LVAD Story". Sleep 44, Supplement_2 (1.05.2021): A323. http://dx.doi.org/10.1093/sleep/zsab072.825.

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Abstract Introduction Congestive heart failure and sleep-disordered breathing frequently coexist. Many of these patients are referred for polysomnography(PSG). Left ventricular assist device (LVAD) is increasingly used as a destination therapy or as a bridge to transplant. This can lead to artifacts in EEG and EKG. The artifact can mask pathological waves or over-reading of pathology. We present a case report of a patient who underwent a PSG on LVAD. Report of case(s) Sixty-six-year old male with severe heart failure with reduced ejection fraction (EF) of 15 % presented with snoring and witnessed apnea. The patient was diagnosed with predominant central sleep apnea (92%) but never initiated BPAP/ST due to an unstable heart. He was placed on LVAD (HeartMate III LVAD, oscillatory speed of 5300 rpm/83.3Hz) as the heart status deteriorated. Repeat polysomnography was done for persistent snoring but improved witnessed apneas revealed a newly appearing artifact. EEG showed a diffuse low amplitude,6–7 Hz frequency waves, and a regularly appearing high voltage sharp-peaked wave. The morphology of alpha wave, K wave, spindles, and delta waves could not be appreciated and hence was unable to perform sleep staging. EKG had electrical artifacts. All troubleshooting maneuvers were unsuccessful in eliminating artifacts. The artifact is generated by the impeller rotational speed of LVAD that ranges from 2400 rpm to 10,00 rpm(oscillation frequencies of 40 Hz to 166.7 Hertz,1Hz == 60 rpm). The device’s artificial pulse causes additional minor peaks. EEG artifact can be improved by moving the amplifier away from the heart and repositioning the patient. Adjusting the low-frequency filter can affect the nasal pressure tracing, delta waves, and stage 3 recognition. Reducing the high-frequency filter frequency by 10 from the LVAD oscillation frequency improves the EKG signal. But this may cut off the frequency component of pathologies like left ventricular hypertrophy. Conclusion The LVAD has been increasingly used in the United States. It is important to improve awareness regarding the artifacts among sleep techs and physicians. Unresolved artifacts may lead to missing serious pathologies in EEG and EKG and also can lead to misreading the waves as pathological leading to unnecessary treatment. Support (if any) An image of EEG and EKG

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Elliott, S., A. A. Firsov i S. B. Leonov. "Oblique shock wave reflection at plasma array presence". Journal of Physics: Conference Series 2100, nr 1 (1.11.2021): 012008. http://dx.doi.org/10.1088/1742-6596/2100/1/012008.

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Abstract This work discusses the effect of a filamentary plasma array on shock wave (SW) reflection pattern and on a shock-induced separation zone geometry. It includes experimental and computational components both. The experimentation was performed in the supersonic blowdown test rig SBR-50 at the University of Notre Dame at flow Mach number M=2, stagnation pressure P0=1.7-2.7 bar and stagnation temperature T0=300 K. Oblique shock wave generator composed of a symmetric solid wedge was installed on the top wall of test section while the filamentary plasma generator was arranged on the opposite wall. Thus, the main SW originating from the wedge impinged the plasma area. As a result of the SW-plasma interaction, the flowfield was significantly modified, including a shift of the main SW upstream and redistribution of wall pressure over the test section. The computational analysis allowed a 3D reconstruction of the SW interaction with the plasma array. The physics of SW-plasma array interaction are also discussed.

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Oswald, Ioan George, Simona Cavalu, Adrian Bumbu, Ciprian Brisc, Vlad Silviu, Éva Todoruț i Pop Ovidiu. "New Devices for Optimization of Renoureteral Lithiasis Treatment Using ESWL". Key Engineering Materials 583 (wrzesień 2013): 155–59. http://dx.doi.org/10.4028/www.scientific.net/kem.583.155.

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In the case of renoureteral lithiasis, shockwave lithotripsy (ESWL) proved to be aneffective and safe method with a low risk of significant clinical consequences for long term Thetherapeutic effect is the result of the pulse amplitude, high pressure and shock wave energy contentfocused on striking stones or urethral calculi. The negative pressure specific shock wave isresponsible for the phenomenon of cavitation. Cavitation plays an important role in thefragmentation of calculus as the technical components accelerates wear mechanism for generatingshock waves in special electrode (the electrohydraulic generator). The main objective of this studyis to find technical solutions in terms of improving energy transfer shock waves from the generatorto the target and reliability/optimization of the shock wave generator (the electrohydrauliclithotriptor EHL vulnerable point).

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Gong, Jinzhe, Martin F. Lambert, Si T. N. Nguyen, Aaron C. Zecchin i Angus R. Simpson. "Detecting Thinner-Walled Pipe Sections Using a Spark Transient Pressure Wave Generator". Journal of Hydraulic Engineering 144, nr 2 (luty 2018): 06017027. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001409.

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HATAZAWA, Masayasu. "Characteristics of Coupled-type Thermoacoustic Sound Wave Generator : Change in Pressure Signals". Proceedings of the Symposium on Stirlling Cycle 2003.7 (2003): 91–94. http://dx.doi.org/10.1299/jsmessc.2003.7.91.

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Nur Damia Asma Rosle, Fatimah Al Zahrah Mohd Saat, Raja Nor Firdaus Kashfi Raja Othman, Irfan Abd Rahim i Patcharin Saechan. "Investigation on Standing Wave Thermoacoustic Generator Using DeltaEC". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 96, nr 2 (23.07.2022): 51–64. http://dx.doi.org/10.37934/arfmts.96.2.5164.

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There is currently an urgent demand to reuse waste heat from industrial processes with approaches that require minimal investment and low cost of operation. Thermoacoustic generator (TAG) is a device that converts heat energy into useful work through the use of acoustic wave, porous media (honeycomb ceramic celcor) and heat exchangers that are all enclosed in a custom-defined resonator. This paper reports the basic design of thermoacoustic generator that is tested using a design software known as a Design Environmental for Low-amplitude Thermoacoustic Energy Conversion (DeltaEC). Many studies have highlighted the relationships between the geometry of the stack and the performance of the device. In this study, attention is given on the impact of the length of stack which was found to be the best at a length of 0.6 m when the frequency of the flow is at 127.4 Hz. Performance indicators like the acoustic power and the temperature difference across the stack have been used to analyse the results. The result shows that the highest acoustic power can be achieved when the generator that work with air at an atmospheric pressure is designed with a resonator of 2.14 m long and a stack with a length of 0.6 m. The maximum value for acoustic power is predicted to be as much as 24.01 kW.

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SAKAMOTO, Daisuke, Chongho YOUN i Toshiharu KAGAWA. "A trial manufacture of a differential pressure wave generator for the dynamic calibration of pressure sensors". TRANSACTIONS OF THE JAPAN FLUID POWER SYSTEM SOCIETY 48, nr 2 (2017): 9–15. http://dx.doi.org/10.5739/jfps.48.9.

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Karunanithi, R., S. Jacob, S. Kasthurirengan, Upendra Behera i D. S. Nadig. "Development of a reliable and simple pressure wave generator for pulse tube refrigerators". Review of Scientific Instruments 75, nr 7 (lipiec 2004): 2479–81. http://dx.doi.org/10.1063/1.1765750.

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Choi, Jingyu, Younghwan Kang, Jaesoon Park, Yeunho Joung i Chiwan Koo. "Development of Real-Time Cuffless Blood Pressure Measurement Systems with ECG Electrodes and a Microphone Using Pulse Transit Time (PTT)". Sensors 23, nr 3 (3.02.2023): 1684. http://dx.doi.org/10.3390/s23031684.

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Research has shown that pulse transit time (PTT), which is the time delay between the electrocardiogram (ECG) signal and the signal from a photoplethysmogram (PPG) sensor, can be used to estimate systolic blood pressure (SBP) and diastolic blood pressure (DBP) without the need for a cuff. However, the LED of the PPG sensor requires the precise adjustment of both light intensity and light absorption rates according to the contact status of the light-receiving element. This results in the need for regular calibration. In this study, we propose a cuffless blood pressure monitor that measures real-time blood pressure using a microphone instead of a PPG sensor. The blood pulse wave is measured in the radial artery of the wrist using a microphone that can directly measure the sound generated by a body rather than sending energy inside the body and receiving a returning signal. Our blood pressure monitor uses the PTT between the R-peak of the ECG signal and two feature points of the blood pulse wave in the radial artery of the wrist. ECG electrodes and circuits were fabricated, and a commercial microelectromechanical system (MEMS) microphone was used as the microphone to measure blood pulses. The peak points of the blood pulse from the microphone were clear, so the estimated SBP and DBP could be obtained from each ECG pulse in real time, and the resulting estimations were similar to those made by a commercial cuff blood pressure monitor. Since neither the ECG electrodes nor the microphone requires calibration over time, the real-time cuffless blood pressure monitor does not require calibration. Using the developed device, blood pressure was measured three times daily for five days, and the mean absolute error (MAE) and standard deviation (SD) of the SBP and DBP were found to be 2.72 ± 3.42 mmHg and 2.29 ± 3.53 mmHg, respectively. As a preliminary study for proof-of-concept, these results were obtained from one subject. The next step will be a pilot study on a large number of subjects.

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Fang, J., P. Jia i W. Liu. "The dynamic performance analysis of the reciprocating continuous wave generator based on the fluid–structure interaction". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, nr 12 (15.08.2011): 2892–99. http://dx.doi.org/10.1177/0954406211408950.

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Using computational fluid dynamics method, dynamic mesh technology, and the dynamic equation of the moving elements, the performance of the reciprocating continuous wave generator is simulated. The influence of the non-Newtonian property of the drilling fluid on the pressure signal is analysed, and the results show that the influence of the non-Newtonian property on the pressure loss at the orifice is small due to the high Reynolds number. The influence of the motion pattern and the exciting frequency of the pilot valve on the dynamic performance of the generator is also analysed, and the results show that: the signal generated from the sinusoidal motion pattern of the pilot valve changes mildly, which is beneficial to the continuous wave generation; during the main poppet opening, the relief valve is at the position of minimum lift, which results in the slowly decreasing pressure, and the rate of signal generation is decreased.

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Wang, Jiun-Jr, Kim H. Parker i John V. Tyberg. "Left ventricular wave speed". Journal of Applied Physiology 91, nr 6 (1.12.2001): 2531–36. http://dx.doi.org/10.1152/jappl.2001.91.6.2531.

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Left ventricular (LV) wave speed (LVWS) was studied experimentally and confirmed in theory. Combining the definition of elastance (E) with the equations for the conservation of mass and momentum shows that LVWS is proportional to the square root of E LA, where L is long-axis length and A is the cross-sectional area, and the density of the blood. (We defined E LA = γ, where γ is compressibility.) We studied nine open chest, anesthetized dogs, three of which were studied during caval constriction when LV end-diastolic pressure was ≤0 mmHg. The hearts were paced at ∼90 beats/min, and LV cross-sectional area was measured by using two pairs of ultrasonic crystals; E was calculated from the LV pressure-area loop. A pulse generator was connected to the LV apex, and LVWS was measured by using two pressure transducers: one near the apex and the other near the base. Their distance was measured roentgenographically and compared with the diameter of a reference ball. LVWS ranged from ∼1 m/s during diastole to ∼10 m/s during systole. The slope of the log c(where c is wave speed) vs. log γ was 0.546, which is in agreement with theory (0.5). When γ ≤ 0, LVWS was ∼1.5 m/s.

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Prasetyowati, Ane, Wisnu Broto i Noor Suryaningsih. "LINEAR GENERATOR PROTOTYPE WITH VERTICAL CONFIGURATION OF SEA WAVE POWER PLANT". Spektra: Jurnal Fisika dan Aplikasinya 6, nr 3 (30.12.2021): 185–200. http://dx.doi.org/10.21009/spektra.063.05.

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There are three types of potential energy sources in the sea: ocean wave energy, tidal energy, and ocean heat energy. Ocean wave energy is a source of considerable energy. Sea waves are an up and down movement of seawater where the energy of sea waves is generated through the effect of air pressure movement due to fluctuations in ocean wave movements. The Ocean Wave Power Plant can use ocean wave energy to convert it into electrical energy. A linear generator is a device that can convert the mechanical energy of linear motion into electrical energy. The application of the ocean wave energy conversion technology, a linear generator system is an electrical machine that functions to convert the mechanical energy of linear motion into electrical energy using the principle of electromagnetic induction. Wave Energy Converter (WEC) technology has been developed with various methods. From the various existing concepts and designs, in general, WEC technology can be classified into three main types, namely Attenuator (horizontal configuration), Point Absorber (linear configuration), Terminator (damping configuration).

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Díaz Tey, Alberto Juan, i Georges Govaere Vicarioli. "Development of a dynamic pressure standard of low amplitudes and frequencies". Measurement Science and Technology 33, nr 3 (29.12.2021): 034004. http://dx.doi.org/10.1088/1361-6501/ac3783.

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Abstract The height of the gravitational wave is an influential magnitude in the estimation of its energy content, a very important parameter in the design of maritime structures such as piers and breakwaters; however, there are reasonable doubts among researchers regarding the quality of its measurement. The objective of the present work was to demonstrate that a stationary calibrated pressure transmitter allows the indirect calculation of the wave height with satisfactory accuracy despite the fact that it is a dynamic event as long as its frequency range is low, as is the case with the gravitational waves of the Costa Rican central Pacific Ocean: between 0.05 and 0.39 Hz. In the absence of a primary standard of periodic pressure disturbances, an alternate path was developed based on the characterization of the parameters of the differential equation characteristic of a pressure measurement system in a shock tube prototype from normal shock wave theory and subsequent verification in a periodic disturbance generator that its attenuation and delay are practically negligible at the frequency of 0.1 Hz. The effect of the different geometry of the chamber of the pressure measurement system used in the sea was evaluated pneumatically by comparison with the dynamic pressure standard in the prototype of the periodic disturbance generator, while the effect of the compressibility of the fluid was evaluated in water in the wave channel of the Laboratory of Maritime Engineering, Rivers and Estuaries of the University of Costa Rica. The results show that the pressure measured from the least-squared adjustment coefficients of an electric current transmitter obtained by stationary calibration is acceptable to estimate the climatology of the gravitational wave characteristic of the Costa Rican central Pacific Ocean with maximum errors of 136 mm in waves of height up to 1.4 m.

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Moreau, Stéphane, C. Becerril i LYM Gicquel. "Large-Eddy-simulation prediction of indirect combustion noise in the entropy wave generator experiment". International Journal of Spray and Combustion Dynamics 10, nr 2 (11.12.2017): 154–68. http://dx.doi.org/10.1177/1756827717740775.

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Compact and non-compact analytical solutions of the subsonic operating point of the entropy wave generator experiment are compared with detailed numerical results obtained by large Eddy simulations. Two energy deposition methods are presented to account for the experimental ignition sequence and geometry: a single-block deposition as previously used and a delayed deposition that reproduces the experimental protocle closely. The unknown inlet acoustic reflection coefficient is assumed to be fully reflective to be more physically consistent with the actual experimental setup. The time delay between the activation of the heating modules must be considered to retrieve the temperature signal measured at the vibrometer and pressure signals at the microphones. Moreover, pressure signals extracted from the large Eddy simulations in the outlet duct using the delayed ignition model clearly reproduce the experimental signals better than the analytical models. An additional simulation with actual temperature fluctuations directly injected at the inlet of the computational domain clearly shows that the pressure fluctuations produced by the acceleration of the hot slug yields indirect noise almost entirely. Finally, the entropy spot is shown to be distorted when convecting through the turbulent flow in the entropy wave generator nozzle. Its amplitude decreases and its shape is dispersed, but hardly any dissipation occurs. The distortion appears to be negligible through the nozzle and become important only when convected over a long distance in the downstream duct. As the dominant frequencies of the entropy wave generator entropy forcing are very low, the effects of dispersion by the mean flow are however weak.

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Vasyliv, S. S., i K. V. Ternova. "Thrust vector control by detonation product injection into the supersonic nozzle area". Technical mechanics 2023, nr 1 (11.04.2023): 68–75. http://dx.doi.org/10.15407/itm2023.01.068.

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To solve the problem of satellite control and stabilization in emergencies, it is proposed to use a detonation rocket engine, which enables active maneuvering to avoid a collision with space debris. The goal of this work is to study a new way of rocket engine thrust vector control by acting with a detonation shock wave on the gas flow in the nozzle. A detonation wave in a supersonic flow in a nozzle was numerically simulated. The simulation was conducted in a non-stationary plane formulation at different angles of inclination of the detonation gas generator that initiates a detonation shock wave to the combustion chamber axis with the use of SolidWorks application software for the 11D25 engine of the Cyclone-3 third stage. The simulation results were used to pre-optimize the location of the detonation gas generator on the nozzle wall. It was found that the effect of the detonation wave on the main gas flow in the nozzle is caused by two force factors: the first is due to the reactive force produced by the detonation product injection into the nozzle and a high-pressure zone on the wall where the detonation gas generator is mounted, and the second is due to a change in pressure distribution over the nozzle surface. In order to increase the effect of the shock wave, the detonation products must be injected parallel to the main gas flow in the nozzle or at some angle. The simulation showed the drawbacks and advantages of detonation product injection at different angles. The detonation wave effect on a supersonic nozzle flow was studied experimentally. A system was developed to record the shock detonation wave propagation using a heat meter. A special nozzle model and a gas generator were developed to initiate a detonation wave interacting with a supersonic air flow. It was found out how the detonation wave separates the main flow from the nozzle walls in the overexpanded mode. The results may be used in the space-rocket industry to provide upper stage maneuvering to avoid a collision with space debris.

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Li, Jian, i Kun Wang. "Research in Surface-Wave Sustained Plasma Fluorescent Lamps". Advanced Materials Research 756-759 (wrzesień 2013): 2099–102. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.2099.

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A cylindrical fluorescent lamp driven by a surface-wave sustained plasma (SWP) generator designed in our lab is researched. A technique to diagnose the SWP plasma column is introduced. Principal physical properties, ion density and electron temperature and the luminance of a fluorescent lamp were studied. Influence factors of luminance such as the microwave power, the gas pressure were studied. The radial distribution of luminance and ion density was also researched. The results show the SWP column is able to generate plasma of about 3ev electron temperature and 1017 m-3 ion density. It is found that the luminance at 200 mm above the base can be about 8000 cd/m2. The luminance changes with the microwave power and the pressure.

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Yakush, S. E., A. S. Iskhakov, V. I. Melikhov i O. I. Melikhov. "Pressure Waves due to Rapid Evaporation of Water Droplet in Liquid Lead Coolant". Science and Technology of Nuclear Installations 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/3087051.

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Flash evaporation of a superheated water droplet in heavy liquid metal coolant (lead) is considered, in application to the analysis of a lead-cooled fast reactor steam generator tube rupture accident. The model is based on thermodynamic equilibrium formulation for the expanding water-steam mixture and inviscid compressible formulation for the surrounding liquid lead, with the interface conditions determined from the solution of the Riemann problem. Numerical solution is performed in the spherically symmetric geometry using a conservative numerical scheme with a moving sharp interface. Transient pressure and velocity profiles in each phase are presented for the parameters typical of the steam generator tube rupture accidents, demonstrating the process of boiling water expansion and pressure wave formation in the coolant. The results obtained are compared with a simplified model which considers the volume-averaged parameters of boiling water droplets and considers coolant as an incompressible liquid. Good agreement between the full and simplified models is demonstrated. Impacts of coolant flow on structures caused by pressure wave propagation and subsequent coolant flow are discussed.

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Lei, Fan, Yan Xue i Donglin Liu. "Simulation of millimeter-sized microwave plasma discharge generator under various conditions". AIP Advances 12, nr 8 (1.08.2022): 085015. http://dx.doi.org/10.1063/5.0105035.

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A microwave plasma generator (MPG) of a sub-millimeter scale might be suitable for biomedical applications. However, there are still many unknowns regarding the MPG discharge behavior at this scale and specific conditions. A two-dimensional MPG model at the millimeter scale and its simulation and relative calculation in the COMSOL Multiphysics software are presented. A MPG filled with argon and helium is simulated, respectively. The frequency of a microwave source of about 5 GHz is considered. The number density and temperature of electrons as well as chemical composition are obtained at different power and pressure conditions. The electron density peaks slightly downstream of the crossing point, and the electron density is slightly asymmetrically in the y-plane due to the fact that the electromagnetic waves are absorbed asymmetrically. The electron temperature is relatively low everywhere, in part, due to the high operating pressure. The electron temperature peaks directly underneath the wave guide where the wave is absorbed. The electron density increases with the increase in the internal pressure and the input power of the MPG, the electron temperature decreases with the increase in the internal pressure of the MPG, but the electron temperature cannot be affected by the input power change of MPG. The amount of excited Ar+ and Ars (metastable atom) increases with the increase in the input power and pressure of MPG, but the amount of excited Ar almost remained unchanged. In addition, the amount of excited He almost remained unchanged, while the amount of excited He+, Hes (metastable atom), and He2+ increased with the increase in the input power and pressure of MPG. The simulation results of this model are thus informative for understanding the physical characteristics of millimeter-sized MPG, and it will provide a solid basis for the future development of such hardware in small plasma capsules for cancer therapy.

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Kumar, J. Kranthi, S. Jacob, R. Karunanithi, G. S. V. L. Narasimham, C. Damu, T. Praveen i M. Samir. "Improved Performance of an Indigenous Stirling Type Pulse Tube Cooler and Pressure Wave Generator". Physics Procedia 67 (2015): 434–39. http://dx.doi.org/10.1016/j.phpro.2015.06.054.

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Caughley, A., J. Meier, M. Nation, H. Reynolds, C. Boyle i J. Tanchon. "Cascading pulse tubes on a large diaphragm pressure wave generator to increase liquefaction potential". IOP Conference Series: Materials Science and Engineering 278 (grudzień 2017): 012137. http://dx.doi.org/10.1088/1757-899x/278/1/012137.

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Ko, Dongwon, Jeongseop Lee, Jinwon Kim i Sanghyun Kim. "Study of leak detection in a pipeline system using a portable pressure wave generator". Journal of the Korean Society of Water and Wastewater 34, nr 2 (30.04.2020): 139–47. http://dx.doi.org/10.11001/jksww.2020.34.2.139.

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Murakami, T., Y. Imai, S. Nagata i M. Takao. "Effects of air chamber and curtain wall geometries on energy conversion performance in a fixed oscillating water column-type wave energy converter". Journal of Physics: Conference Series 2217, nr 1 (1.04.2022): 012069. http://dx.doi.org/10.1088/1742-6596/2217/1/012069.

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Abstract An oscillating water column-type wave energy extractor is composed of an air chamber, an air turbine and a generator. The energy conversion process is compounded of the primary conversion in an air chamber and the secondary conversion of an air turbine. The oscillating water column-type wave energy extractor is considered to be safe even under dirty weather conditions. For societal implementation, there is a need to make a design method which can consider the water surface motion, the pressure fluctuation in an air chamber, the rotations of an air turbine and a generator. At here, the authors carried out the 2-dimensional wave tank tests using the model oscillating water column equipped with the impulse turbine and a generator to obtain the experimental data needed to make this design method. In the experiments, the effects of the air chamber and curtain wall geometries on energy conversion performance in regular wave conditions were investigated. As the results, it is noticed that the geometry of the curtain wall and the vortex shedding from the corners of curtain wall affect the primary conversion efficiency.

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Macola, G. Grasso, G. L. Tonazzi, G. Gatti, S. Carpanp i V. Giudice. "Renal Tubular Damage Evaluation through Enzyme Change Monitoring after Extracorporeal Shock Wave Lithotripsy". Urologia Journal 60, nr 1 (luty 1993): 45–50. http://dx.doi.org/10.1177/039156039306000110.

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To evaluate a possible onset of “biological effects” following ESWL lithotripsy, the Authors measured urinary excretion levels of two enzymes, NAG and GGT. In fact, a rise in the levels of these enzymes is regarded as an early and sensitive sign of renal injury. Fourteen patients with no complicated renal lithiasis were selected; the enzymatic levels before and after a single treatment with Lithostar Plus, a lithotriptor supplied with an electromagnetic impact wave generator, were measured. The results show that a single treatment doesn't produce any significant variation in their excretion. These results were discussed and their significance analysed. Probably, they could be explained by the lower pressure produced in the focal area by the impact wave, due to an electromagnetic generator.

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Rubel, Viktoria, Vyacheslav Rubel, Jan Ziaja i Roman Yaremiychuk. "Development of a mathematical model of the operation of the swab generator valve". Technology audit and production reserves 5, nr 1(67) (21.10.2022): 6–10. http://dx.doi.org/10.15587/2706-5448.2022.265815.

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The object of research in the work is a mathematical model of the operation of a hydrodynamic well generator of the spring-valve type. The existing problem lies in the fact that vibrating wave swabbing differs from known methods of vibrating wave influence on the near-breakout zone of the formation in its ease of execution and, as a result, a much smaller range of equipment. At the same time, its effectiveness should not be inferior to known methods because the treatment of the formation is carried out by elastic low-frequency pressure fluctuations against the background of depression on the formation. Since the swab generator valve is, in fact, a hydrodynamic well generator (HWG) of the spring-valve type, the processes of pressure fluctuations in the considered devices will be similar. However, because of the review of HWG designs, the presence of a mathematical model describing the operation of rotor-type devices, and not valve type, was revealed. Despite the fact that the mathematical model takes into account all the main factors that determine the process of the HWG piston movement, this model cannot be used to describe the operation process of the swab generator valve. Due to the absence of a pulsating flow created at the wellhead by pumping units. Taking this fact into account, as well as taking into account the compressibility of the liquid passing through the valve, a new mathematical model was developed. It describes both the process of operation of a spring-valve type HWG operating in a well on pump-compressor pipes, and the operation of a swab generator valve that is lowered into a well on a rope. Thanks to this, it is possible to obtain the parameters of the oscillating system: geometric dimensions, inertial mass of moving parts, stiffness of the spring, coefficient of viscous friction between the piston and the valve body, as well as parameters of the working fluid: pressure, flow and its rheological properties. In comparison with the similarly known technology of vibration wave impact on a formation with known HWG, it provides such advantages as a higher speed of movement and frequency of oscillations of the moving end of the spring from the identified essential parameters of the oscillating system and the working fluid of the spring (100–1000 N/mm), consumption of working liquid (10–130 m3/h), valve opening pressure (1–7 MPa). This will make it possible to calculate a helical cylindrical compression spring made of round steel for its operation in the valve of the swab generator without collision of turns.

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Andersen, Niklas Enoch, Jakob Blåbjerg Mathiasen, Maja Grankær Carøe, Chen Chen, Christian-Emil Helver, Allan Lynggaard Ludvigsen, Nis Frededal Ebsen i Anders Hedegaard Hansen. "Optimisation of Control Algorithm for Hydraulic Power Take-Off System in Wave Energy Converter". Energies 15, nr 19 (27.09.2022): 7084. http://dx.doi.org/10.3390/en15197084.

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Wave energy converters are still a maturing technology and, as such, still face a series of challenges before they can compete with already-established technologies. One of these challenges is optimising the amount of energy extracted from the waves and delivered to the power grid. This study investigates the possibility of increasing the energy output of the existing hydraulic power take-off system of a wave energy converter made by Floating Power Plant during small-scale testing of their hybrid wind and wave energy platform. This system consists of a floater arm that rotates an axle when displaced by the waves. When the axle rotates, two hydraulic cylinders are actuated, displacing oil to run through a hydraulic motor driving an electric generator. The energy extraction is controlled by implementing a control algorithm on a series of on/off valves, which decouples the two hydraulic cylinders driving the hydraulic motor, and by varying the applied torque from the generator to match the wave conditions. Finally, it is investigated whether adding high-pressure pathways to the cylinder pressure chambers is beneficial for maximum power point tracking with reactive control. The analysis is conducted through a numerical model developed in Simulink and verified by comparison to the experimental setup supplied by Floating Power Plant. The study finds that a continuous valve switching strategy is optimal compared to end-point switching and reactive control with high-pressure pathways.

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Klimov, A. I., N. K. Belov, V. G. Brovkin i A. S. Pashchina. "Study of Heterogeneous Plasma Created by Magneto-Plasma Compressor and Erosive Capillary Discharge". Journal of Physics: Conference Series 2100, nr 1 (1.11.2021): 012006. http://dx.doi.org/10.1088/1742-6596/2100/1/012006.

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Abstract Magneto-plasma compressor with a pulsed capillary erosive plasma generator (MPC-EP) has been designed, manufactured and tested at the first time. This MPC-EP was used to study the physical properties of a high-energy long-lived heterogeneous plasma (ELHP) created by pulsed capillary erosive plasma generator (EP) at the wide range of pressure and temperature. The results of measurements of the parameters of the shock wave created by the MPC-EP, as well as optical spectroscopy and soft X-ray spectroscopy are presented.

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Karakulov, M. N., D. V. Starshev i E. S. Korobeynikova. "Improving the Design of the Gas-Mechanical Wave Generator Distributor". Vestnik IzhGTU imeni M.T. Kalashnikova 25, nr 1 (2022): 38–43. http://dx.doi.org/10.22213/2413-1172-2022-1-38-43.

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In modern industry, the issue of improving the reliability of a particular mechanism is relevant, especially when the work takes place in an aggressive environment. Oil and gas companies are interested than anyone else in solving these problems. This article will give an example of solving one of the problems of modern industry, this is the improvement of the design of the distributor of the gas mechanical waveguide. Such devices are used to generate a deformation wave of flexible elements of gas-hydraulic engines and control the operation of these devices. The use of gas-hydraulic engines with gas-mechanical wave generators is due to their ability to work using the potential energy of the substance transported through the gas pipeline, which allows them to be used in remote regions with a low level of infrastructure development, for example, in the Far North. A little-studied issue is the determination of the moment of distribution mechanism straining and simplification of its design. Variants of the design of the distributor of the gas-mechanical wave generator of the prototype plunger gas-hydraulic engine are considered. The positive and negative aspects of using additional reversing mechanisms in the distributor drive are given. A considered improvements of distributor spool geometry modification are realized by addition of grooves, so that the device is triggered using the pressure of the transported medium. The calculations showed the ways of grooves positioning and determination of their angle displacement to ensure operation. A relation has been obtained that makes it possible to determine the magnitude of the torque that occurs on the shaft of the distributor spool. It has been established that the displacement angle of the spool slots has a significant effect on the magnitude of the torque.

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Napole, Cristian, Oscar Barambones, Mohamed Derbeli, José Antonio Cortajarena, Isidro Calvo, Patxi Alkorta i Pablo Fernandez Bustamante. "Double Fed Induction Generator Control Design Based on a Fuzzy Logic Controller for an Oscillating Water Column System". Energies 14, nr 12 (12.06.2021): 3499. http://dx.doi.org/10.3390/en14123499.

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Oscillating water column (OWC) systems are water power generation plants that transform wave kinetic energy into electrical energy by a surrounded air column in a chamber that changes its pressure through the waves motion. The chamber pressure output spins a Wells turbine that is linked to a doubly fed induction generator (DFIG), flexible devices that adjust the turbine speed to increase the efficiency. However, there are different nonlinearities associated with these systems such as weather conditions, uncertainties, and turbine stalling phenomenon. In this research, a fuzzy logic controller (FLC) combined with an airflow reference generator (ARG) was designed and validated in a simulation environment to display the efficiency enhancement of an OWC system by the regulation of the turbine speed. Results show that the proposed framework not only increased the system output power, but the stalling is also avoided under different pressure profiles.

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Yan, Zhidan, Yanfeng Geng, Chunming Wei, Tiannong Wang, Tingzheng Gao, Jing Shao, Xiufeng Hu i Menglei Yuan. "Design of a continuous wave mud pulse generator for data transmission by fluid pressure fluctuation". Flow Measurement and Instrumentation 59 (marzec 2018): 28–36. http://dx.doi.org/10.1016/j.flowmeasinst.2017.11.008.

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