Gotowa bibliografia na temat „Pressure Wave Generator (PWG)”

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.

. 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.

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.

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.

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.

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.

Low cost cryocoolers suitable for long term use in industrial environments are required for superconducting technologies to be competitive with copper based devices in real world applications. Industrial Research Limited is developing such cryocoolers, which use metal diaphragm based pressure wave generators to convert electrical energy to the gas volume displacement required. This project explores methods of increasing the volume displacement provided by the diaphragms while ensuring the components stay within the acceptable material limits. Various alternative diaphragm shapes are tested against the currently used shape through finite element analysis. In addition to testing alternative diaphragm shapes, each shape’s dimensions are optimised. It is concluded the currently used design can be improved by offsetting the piston rest position and slightly reducing the piston diameter. A more detailed analysis is carried out of the bend radii created during fabrication of the diaphragm, and physical testing is performed to verify unexpected calculated stress concentrations. High stresses are observed, however it is concluded unmodelled material features have a large effect on the final stress distribution. It is recommended advantageous shape changes calculated in the first part of the work be trialled to increase the efficiency of the cryocooler, and that investigation of the material behaviour during commissioning of the pressure wave generator be carried out to better understand the operational limits of the diaphragms.

A single-stage pulse tube cryocooler was designed and fabricated to provide cooling at 50 K for a high temperature superconducting (HTS) magnet, with a nominal electrical input frequency of 50 Hz and a maximum mean helium working gas pressure of 2.5 MPa. Sage software was used for the thermodynamic design of the pulse tube, with an initially predicted 30 W of cooling power at 50 K, and an input indicated power of 1800 W. Sage was found to be a useful tool for the design, and although not perfect, some correlation was established. The fabricated pulse tube was closely coupled to a metallic diaphragm pressure wave generator (PWG) with a 60 ml swept volume. The pulse tube achieved a lowest no-load temperature of 55 K and provided 46 W of cooling power at 77 K with a p-V input power of 675 W, which corresponded to 19.5% of Carnot COP. Recommendations included achieving the specified displacement from the PWG under the higher gas pressures, design and development of a more practical co-axial pulse tube and a multi-stage configuration to achieve the power at lower temperatures required by HTS.

Дисертація присвячена проблемі удосконалення та дослідження технічних засобів імпульсно-хвильової дії на нафтогазоносні пласти. Обгрунтовано розроблення та запропоновано нову конструкцію гідравлічного генератора імпульсно-хвильової дії на нафтогазоносні пласти. В результаті моделювання процесів, які виникають в генераторі при його роботі, отримано залежність сумарного звукового опору конструкції з отворами від значень її конструктивних та механічних параметрів. Розроблено експериментальну установку для дослідження робочих характеристик генератора при зміні фізичних параметрів його робочих елементів. Розроблено методику проведення досліджень генератора безпосередньо в свердловині та при дії на пласт з використанням імітатора пласта. Отримано графіки акустичного тиску, температури та гідравлічних коливань при роботі генератора, наведено залежності, що характеризують зміну цих параметрів. Отримано аналітичні залежності частоти та амплітуди імпульсів генератора від фізичних параметрів генератора (довжини клапану та ваги шатуна). Розрахунки за розробленими аналітичними залежностями мають високий ступінь кореляції з результатами експериментів (більше 0,85). Нова конструкція гідравлічного генератора імпульсно-хвильової дії на нафтогазоносні пласти успішно пройшла дослідно-промислові випробування на свердловинах Яксманіца-33, 8-Старий Самбір, 1-Семаківська та ін. як при освоєнні свердловин так і при інтенсифікації видобування вуглеводнів.
Диссертация посвящена проблеме усовершенствования и исследования технических средств импульсно-волнового воздействия на нефтегазоносные пласты. В работе проведено исследование современного состояния методов и средств повышения производительности нефтегазовых скважин в целом и технологии импульсно-волнового воздействия на пласт в частности. В диссертационной работе решена научно-техническая задача в области разработки и исследования специального технологического оборудования -разработана новая конструкция технического средства импульсно-волнового воздействия на нефтегазоносные пласты, которое дает возможность сделать управляемым процесс импульсно-волнового воздействия на пласт и повысить производительность нефтегазовых скважин. Описана работа гидравлического генератора в скважине. Основное влияние на продуктивный пласт осуществляет энергия гидродинамических пульсаций жидкости, в связи с чем гидравлический генератор размещается в зоне перфорации. При этом отверстия перфорации снижают звуковой сопротивление конструкции. В результате моделирования процессов, возникающих в гидравлическом генераторе импульсно-волнового воздействия при его работе (акустические, гидродинамические и тепловые процессы), предложено при расчете звукового сопротивления системы «скважина - продуктивный пласт» учитывать наличие отверстий перфорации. Соответствующие изменения внесены в формулу для расчета суммарного звукового сопротивления конструкции. На частоту и амплитуду работы генератора влияет значительное количество факторов, аналитически связать которые между собой достаточно сложно, поэтому исследование рабочих характеристик генератора осуществлено экспериментальным путем с применением теории планирования эксперимента. Разработана экспериментальная установка для исследования рабочих характеристик генератора при изменении геометрических размеров его элементов. Разработана методика проведения исследований генератора непосредственно в трубе и при воздействии на пласт с использованием имитатора пласта. Разработана измерительная схема экспериментальной установки. На экспериментальной установке измерялись: температура рабочей жидкости; акустический отзыв (вибрация) внешней поверхности рабочей камеры, в которой находился рабочий элемент гидравлического генератора; перепад давления на рабочей камере; расход рабочей жидкости; колебания давления жидкости в трубопроводе после рабочей камеры; уровень в емкости для подачи фильтровальной жидкости; электронные весы для взвешивания емкости с фильтровальной жидкостью. Кроме того, во времени снималась общая тепловая картина экспериментальной установки. Для измерения акустического отзыва (вибрации) использовался электретный микрофон цифрового диктофона и пьезомикрофон. Полученные данные с микрофонов, для извлечения полезных данных, обрабатывались с помощью быстрого преобразования Фурье. Спектральные составляющие акустических сигналов от гидравлического генератора импульсно-волнового воздействия имели частоты от 10 Гц до 8 кГц. При этом частоты от 10 до 60 Гц отвечают за частоту опрокидывания клапана, а высокие частоты - это субгармонических составляющие, которые сопровождают процесс опрокидывания. Их амплитуда зависит от имеющихся резонансов в конструкции генератора. Из анализа изменения температуры определена эффективность гидравлического генератора при нагревании жидкости. За нулевой уровень эффективности выбрано изменение температуры при движении жидкости без размещения генератора в трубопроводе. Эффективность работы генератора было видно в течение всего времени его работы, поскольку разница температур постоянно росла. Для оценки гидродинамических пульсаций использовано датчик давления ИДТ-8. Датчик давления работл в комплекте с генератором сигналов (синусоидального типа), усилителем мощности и трансформаторным блоком, который согласовывал входное сопротивление датчика и выходное сопротивление усилителя. Гидродинамические пульсации также на чисто качественном уровне фиксировались двумя пружинными манометрами. При изменении расхода частотный спектр гидродинамических пульсаций генератора составлял от 25 до 100 Гц. В результате исследований были получены типичные графики акустического давления, температуры и гидравлических колебаний при работе генератора, приведены зависимости, характеризующие изменение этих параметров. Получены аналитические зависимости частоты и амплитуды импульсов генератора от физических параметров генератора (длины клапана и веса кривошипа). Полученные расчеты по разработанным аналитическим зависимостям имеют высокую степень корреляции с результатами экспериментов (более 0,85). Усовершенствованная конструкция импульсно-волнового воздействия на нефтегазоносные пласты успешно прошла опытно-промышленные испытания на скважинах Яксманица-33, 8-Старый Самбир, 1-Семакивська и др. как при освоении скважин, так и при интенсификации добычи углеводородов. Приведенные схемы, на которых показано широкие возможности при применении данной технологии: работа на скважинах под давлением, с использованием колонны гибких труб, насосных агрегатов или компрессорных установок. Как показала практика, использование струйных насосов сразу после обработки пласта гидравлическим генератором значительно повышает эффективность проводимых работ. Промышленные испытания разработанного гидравлического генератора подтвердили его эффективность и перспективность широкого внедрения в нефтегазодобывающей практике.
The thesis is devoted to the study and improvement of pulse-wave action devices on the oil and gas saturated layers. Justified the development and new design of hydraulic generator pulse-wave impact on oil and gas saturated layers was proposed. As the result of processes simulation occurring in the generator when it is operating, the dependence of the total sound resistance in generator with the holes on the values of its structural and mechanical parameters was developed. An experimental setup for studying the performance of the generator in case of changing physical parameters of its work items was developed. The method of the directly generator research in the well and when exposed to formation using the layer simulator was developed. The acoustic pressure, temperature and hydraulic vibration during generator operation was obtained, the dependences describing the variation of these parameters. Obtained analytical dependence of the frequency and amplitude of the pulse generator on its physical parameters (length and weight of the valve rod) was obtained. Calculations by the developed analytical dependences have a high correlation degree with the experimental results (more than 0.85). The new design of hydraulic pulse-wave action generator on the oil and gas saturated layers has been successfully pilot-scale tested on wells Yaksmanitsa-33, 8-Staryj Sambir, 1-Semakivska and others as well development and the intensification of the hydrocarbons production.

Les propriétés mécaniques des tissus biologiques sont des paramètres importants en médecine : ce sont des biomarqueurs du fonctionnement normal ou pathologique d'un tissu. En effet, ces propriétés peuvent être affectées par certaines conditions mécaniques telles que l'application d'une contrainte externe, comme l'hypertension ou un traumatisme, mais également par la présence de certaines maladies, telles que le cancer, la fibrose, l'inflammation, la maladie d'Alzheimer, ou bien tout simplement avec l'âge. La palpation réalisée par le médecin permet de discerner ces changements mais ce geste est qualitatif et ne peut accéder à des organes profonds. L'élastographie-IRM reste une méthode quantitative, robuste, d'une grande précision, qui permet de sonder l'élasticité et la viscosité des tissus. Elle consiste à mesurer le champ de déplacement d'une onde de cisaillement induite dans l'organe ciblé par une technique IRM en contraste de phase. Les modules viscoélastiques sont alors déduits après inversion de l'équation d'onde. Malgré cela, la justesse de cette technique n'a pas encore été pleinement établie. L'élastographie-IRM est en cours d'implémentation en routine clinique sur des patients atteints de maladies hépatiques chroniques ou bien pour caractériser des tumeurs dans le cas de cancer du sein. L'application aux autres organes protégés, tels que le cerveau ou les poumons, reste encore du domaine de la recherche à cause de la difficulté d'y induire des ondes mécaniques (protection naturelle de la boîte crânienne ou de la cage thoracique). C'est dans ce contexte qu'intervient un volet de mon travail de thèse : la mise en place, la caractérisation et l'optimisation d'un système induisant des ondes mécaniques dans les organes profonds. L'approche originale suivie a été d'utiliser les voies naturelles permettant d'amener l'onde de pression aux poumons ou bien à l'encéphale, différente des approches classiques consistant à traverser les barrières protectrices. Ce générateur d'onde de pression nous a permis d'obtenir des amplitudes d'onde allant de 6 µm à 30 µm dans l'ensemble du cerveau, amplitudes suffisantes afin d'en déduire les modules viscoélastiques du cerveau entier. D'autre part, un travail important s'est attaché à la réalisation d'un schéma original de correction des mouvements du patient en élastographie-IRM. Nous avons mis en évidence comment ces mouvements peuvent entraîner une discordance des composantes du champ de déplacement, nécessitant alors d'être corrigées. La correction proposée est composée d'une première étape dont la finalité est de recaler spatialement l'ensemble des volumes acquis, puis d'une seconde étape permettant de rétablir les composantes du champ de déplacement dans la même base orthonormée. Nous avons évalué numériquement et expérimentalement le biais induit quand aucunes corrections n'étaient appliquées sur ces données ainsi que l'apport de ces deux étapes de correction. Un travail préliminaire sur l'étude de la reproductibilité des acquisitions (phase en particulier) a été nécessaire. Enfin, l'ensemble des résultats de ces deux volets nous ont permis de réaliser des acquisitions d'élastographie du cerveau complet et d'obtenir des cartes du champ de déplacement de qualité. Ainsi, nous avons pu montrer la tendance des ondes mécaniques à suivre les directions privilégiées des fibres du cerveau, résultats que nous avons commencé à confronter aux observations faites en DTI.

Cryocoolers are mechanical devices that produce cold at temperatures below -150oC. Work required to produce the cold is supplied by a Pressure Wave Generator (PWG). This thesis is concerned with the development and analysis of Stirling type pulse tube cooler (PTC) systems of low and medium capacities along with performance improvement of PWG and design of a novel oil free and low maintenance helium recondensation system based on Stirling type pulse tube coolers and Joule-Thomson expansion. Pressure Wave Generator is a crucial part of pulse tube cooler system. Performance of PWG depends on many parameters like the seal gap, piston diameter etc. E ects of these parameters have been studied in detail. Analysis was done to arrive at optimal values and a methodology is suggested to improve performance. The analysis was applied extensively to indigenously developed Pressure Wave Generator (PWG-1). A signi cant improvement, reduced mechanical losses and lowered input electric current, has been found by application of the suggested methodology. The development of pulse tube coolers of low and medium capacities was studied. In low capacity coolers, the available PV power is low; thus, requiring an ultra e cient design. In medium capacity coolers, the available PV power can pose problems like acoustic matching, streaming etc. A low capacity pulse tube cryocooler capable of 0.5 W at 80 K and acoustically matched to indigenous Pressure Wave Generator PWG-1 was designed, fabricated and tested. Inertance tube con guration which plays signi cant role in low input power coolers has been analyzed. A no load temperature of 74 K was achieved with input power of 59 W; corresponding to a cooling power of 0.22 W at 80 K. The amplitude of mass ow passing into the pulse tube cooler has been measured by using a hot wire anemometer calibrated in oscillatory ow condition. A medium capacity pulse tube cryocooler capable of 10 W at 80 K was designed and developed. It requires an estimated input PV power of 375 W. On the other hand, the only available large PWG for this work, PWG-2, has a rated PV power output of 900 W at the rated piston stroke, thus posing the problem of acoustic matching. Improvement of acoustic matching between the PTC and PWG was studied by varying lling pressure, inertance tube con guration, and by using a long transfer line. A no load temperature of 72 K corresponding to 1 W at 80 K was achieved. It is concluded that steps to improve acoustic matching are useful only to a limited extent and acoustic matching has to be ensured at the design stage itself. A medium capacity two stage pulse tube cooler capable of reaching 25 K is described. Analytical proof has been given to shown that a two stage pulse tube cooler is thermo-dynamically less e cient than a single stage pulse tube cooler. But a two stage PTC is required to reduce regenerator losses. A no load temperature of 40.4 K was achieved at 24.1 bar lling pressure with an input power of 750 W. The e ects of pulse tube volume and regenerator con guration were experimentally investigated. The results point out the interplay of pressure drop and regenerator ine ectiveness losses. It is concluded that high mass ow from the PWG-2 is the reason for ine ectiveness of regenerator. A twin cooler design to reduce the mass ow of PWG-2 reaching the coldest stage has been proposed. A novel oil free and low maintenance helium recondensation system has been designed with a liquefaction rate of 17.86 liters per day corresponding to a cooling power of 0.53 W at 4.2 K. The system reaches liquid helium temperature by precooling helium gas in tube-in-tube heat exchangers, assisted by Stirling type pulse tube coolers operating at 80 / 25 K and two stage JT expansion. The cooling powers required of the pulse tube coolers are 14.22 at 80 K and 1.6 W at 25 K respectively. The twin cooler is capable of meeting these cooling power requirements. Design and development of tube-in-tube heat exchangers and JT valves are discussed.

碩士
國立臺北科技大學
製造科技研究所
89
This thesis aims to design a technique for the manufacturing of the square pressure waves generator that can generate the square pressure signals to test the dynamic characteristics of the hydraulic system. The square pressure waves generator is composed of several components. The design and manufacture of the high-speed switch among them is the most important technique. The way of the continuous rotation of machine is used to be the principle of the on and off switch of the square pressure waves generator. The differential method is used to achieve the high frequency switch in order to replace the directional control valve that is composed of rotary and slide spools. During the real design and manufacture of the high-speed switch, we find that the function of the square pressure waves generator can be influenced by the important facts, such as surface roughness, clearance, the shape and dimensioning of the cannelure, pressure balance and lubrication. The square pressure waves generator is fabricated by the high-speed switch and other components. It is installed on the test platform and linked up with transmission equipment and driving motor. Thus, the whole square pressure waves generator has been completed with normal function. The test results in different frequency and pressure can achieve the anticipation, and can possess the good shape of the square pressure wave and the high frequency characteristics of 2000Hz. The main tasks of the study is to generate the square pressure wave signals up to the frequency of 2000 Hz in order to raise a direct, effective test equipment to find the dynamic characteristics of the hydraulic control system and can promote the system quality and increase the industrial competition.

碩士
國立臺北科技大學
機電整合研究所
97
The dynamic characteristics of the hydraulic system are the key factor for detailed control. This study aims to investigate the dynamic characteristics of square wave which produce from a reciprocating pressure square wave generator (RPSWG). RPSWG consists of 3-way 2-position valve and a spool which excited by a solenoid to generate pressure square wave. Experimental parameters are hydraulic input pressure, frequency, back pressure, spool velocity, and chamber volume. A piezoelectric pressure sensor was used for measuring the dynamic pressure of hydraulic system through the Fourier Fast Transform analyzer. system identification obtained with MATLAB analyzing software. As a result, the hydraulic pressure increases cause the system instable. The higher operating frequency makes The shorter time of steady state to promote the velocity of response. The back pressure increases cause the overshot reduction and the rising time increase. The speed of spool is quicker then the transition state will be shorter. The chamber volume of pressure is smaller can reduce the period of transition state and increase the reaction rate.

碩士
國立臺北科技大學
製造科技研究所
94
This thesis is to study the dynamic characteristics of pressure square wave generator (PSWG) and hydraulic piping. Using PSWG as excitation source to generate pressure square wave, the output dynamic-pressure signals were measured by using piezoelectric pressure sensor and analyzed by FFT analyzer. The time-domain and frequency-domain response can be used to compare the difference of dynamic characteristics. First, the pressure drop at outlet of PSWG were calculated when the input pressure or frequency is to be changed. In addition, the dynamic characteristics of flexible-hydraulic hose can also obtain using different hose lengths, diameters, and bending radii. Finally, the difference of dynamic characteristics between rigid piping and flexible hose would be analyzed and compared. Results show the PSWG has a largest amplitude 1.22 MPa output when the frequency is 200 Hz. The frequency characteristics curve is also close to the ideal curve, which produced by a function generator. For the flexible hoses, the larger the hose length, hose diameter and bending radius used, the larger the pressure drop will be. Similarly, the smaller the fundamental frequency peak value and bandwidth can be obtained. This means that the more filled fully with hydraulic oil leads to the larger damping effect. In the different materials of hydraulic piping system, larger phase-lag degrees can be obtained when the frequency increases. Both rigid piping and flexible hose have resonant frequency nearly 70 to 100 Hz. It must be careful to deal with the resonant effect in a hydraulic piping system.

For developing the available hydrocarbon reserves and for exploring new reservoirs, deeper and more complex wells are drilled. Drilling such deeper and complex wells requires a constant monitoring and controlling of the well paths. Therefore, the bottom hole assembly, the lower section of the drill string above the drill bit, is equipped with numerous measuring sensors for collecting geological and directional data while drilling. The collected data have to be transmitted to the surface in real time. Prior to transmit the data measured downhole to the surface, they are processed and translated into a binary code. Accordingly, the data will be represented as a series of zeroes and ones. The most common method for data transmission in boreholes is the so called mud pulse telemetry which sends the information through the drilling mud inside the drill string by means of coded pressure pulses. There are two types of devices available for downhole pressure pulses generation. The first type is the (positive or negative) pressure pulser which transmits the data by quasi-static variations of the pressure level inside the drill string. The second type is the (rotating or oscillating) mud siren which transmits the data by generating continuous pressure waves at specific frequencies. The main disadvantage of the mud pulse telemetry is its low data transmission rate which is about 10 bps. This data rate is very low compared to the measured amount of raw data. Therefore, the efficiency of the mud pulse telemetry must be improved, so that the data could be transmitted at higher rates. The present research work presents different developed and tested concepts for increasing the efficiency and the data transmission rate of the mud pulse telemetry. Both, the transmitter and the receiver end, were taken into consideration by developing the new concepts. Different hardware and software tools were used for performing the present research work. The available flow loop test facility and the experimental prototypes of the mud siren and positive pulser were used. The test facility was extended in order to enable the investigation of the new concepts. The available 3D numerical model (ANSYS CFX) was modified and extended in order to study the new concepts. At the transmitter end, a novel concept for a hybrid mud pulse telemetry system was developed and successfully tested. Here, two different types of mud pulse telemetry could be used in a combination, such as a mud siren and a pressure pulser. The developed concept was registered at the German Patent and Trade Mark Office for a patent in 2018. Two concepts for a multi-frequency mud siren were developed for simultaneous generation of two frequencies. In the first approach, two sets of stator/rotor were installed in a row connection, while they were installed in a parallel connection in the second approach. The two concepts were registered at the German Patent and Trade Mark Office for patents in 2015. An experimental multi-frequency generator was built and used for testing of several new ideas, such as transmitting the data using several carrier frequencies at the same time, transmitting the data with different wave forms (sine, sawtooth, triangle and rectangle), or transmitting the data using the chirp modulation. The innovative design of the experimental multi-frequency generator was registered at the German Patent and Trade Mark Office for patents in 2016. At the receiver end, two different methods for processing and analyzing the received multi-frequency signals using the Wavelet and Fourier analysis were drafted and tested. A novel concept for the use of a multi-sensor receiver was developed and successfully tested. The use of a multi-sensor receiver could strongly improve the detection of the received signals.:Table of Contents Declaration ii Abstract iii Acknowledgements v Table of Contents vi List of Abbreviations x List of Symbols xii CHAPTER 1 Introduction 1 CHAPTER 2 Modern Drilling Technology and Low Data Transmission Rate as a Limitation 5 2.1 Introduction to the modern drilling technology 5 2.1.1 Directional drilling technology 5 2.1.2 Steering technology 6 2.1.3 Measuring technology 8 2.1.4 Technology of data transmission in boreholes 9 2.2 Low data transmission rate as a problem with respect to the whole drilling process 13 CHAPTER 3 Fundamentals of Communication Technology 16 3.1 Modulation techniques for data transmission in baseband 16 3.2 Modulation techniques for data transmission in passband 17 3.3 Multiple frequency and chirp spread spectrum modulation techniques 19 3.4 Digital signal processing 21 3.4.1 Fourier transformation 21 3.4.2 Continuous wavelet transformation 23 3.4.3 Filtering 24 CHAPTER 4 State of the Art for Mud Pulse Telemetry Systems 26 4.1 Historical development of mud pulse telemetry including latest improvements applied for increasing its data transmission rate 26 4.2 Available types of mud pulse telemetry devices 30 4.2.1 Negative pulser 31 4.2.2 Positive pulser 32 4.2.3 Mud siren 32 4.2.4 Oscillating shear valve 33 4.3 Limitations of data transmission via mud pulse telemetry 34 4.3.1 Effect of noise sources in the mud channel on the transmission signal 34 4.3.2 Effect of attenuation in the mud channel on the transmission signal 36 4.3.3 Effect of reflections and their interference with the main transmission signal 37 4.3.4 Pass and stop bands 38 4.4.5 Minimum transmission time slot 38 CHAPTER 5 Novel Concepts and Tools for Increased Data Transmission Rates of Mud Pulse Telemetry 40 5.1 Transmitter end 41 5.1.1 Hybrid mud pulse telemetry (HMPT) 41 5.1.2 Multi-frequency generator 43 5.2 Receiver end 45 5.2.1 Investigation of the Wavelet analysis suitability for multi-frequency signal detection 45 5.2.2 Flexible placement of multi-sensor receiver 46 CHAPTER 6 Laboratory Test Facility and Used Hard and Soft Tools 49 6.1 Laboratory test facility for hydraulic data transmission in boreholes 49 6.2 Experimental prototypes of the pressure pulsers and mud siren 53 6.3 3D numerical simulation model for the test facility and mud siren 55 6.4 MATLAB software 58 CHAPTER 7 Hybrid Mud Pulse Telemetry (HMPT) System 59 7.1 Combination of mud siren and negative pressure pulser 60 7.2 Combination of mud siren and positive pressure pulser 63 7.3 Evaluating the laboratory investigations of the hybrid mud pulse telemetry (HMPT) system 66 CHAPTER 8 Mathematical and Numerical Investigation of the Concept of the Multi-Frequency Mud Siren 68 8.1 Preliminary considerations for the concept of the multi-frequency mud siren 69 8.2 Mathematical model investigation of different approaches for the multi-frequency mud siren concept 71 8.2.1 Multi-frequency mud siren with stators and rotors in a row 72 8.2.2 Multi-frequency mud siren with parallel connection of stators and rotors 74 8.3 Numerical model investigation of multi-frequency mud siren with two sets of stator/rotor in a row 77 8.3.1 Numerical simulations for data transmission with a multi-frequency mud siren using two carrier frequencies 79 8.3.2 Evaluation of the simulation results 81 8.3.3 Increasing the transmission reach of the mud siren for deep drilling operations 83 CHAPTER 9 Laboratory Investigations of Multi-Carrier Hydraulic Data Transmission Using an Experimental Multi-Frequency Generator 85 9.1 Laboratory multi-carrier frequency transmission tests 87 9.2 Investigation of the Wavelet analysis suitability for the detection of multi-frequency signal transmitted in boreholes 95 9.3 Initial investigations of hydraulic data transmission using chirp modulation and different pressure wave forms 100 9.3.1 Data transmission using chirp modulation (Chirp Spread Spectrum, CSS) 100 9.3.2 Data transmission using different wave forms 101 CHAPTER 10 Investigation of the Use of a Multi-Sensor Receiver for Improving the Hydraulic Data Transmission in Boreholes 104 10.1 Numerical model investigation of the use of a multi-sensor receiver 104 10.1.1 Data transmission using single-input and multiple-output (SIMO) 104 10.1.2 Data transmission using multiple-input and multiple-output (MIMO) 107 10.2 Laboratory investigations of the use of a multi-sensor receiver 108 10.3 Evaluating the use of a multi-sensor receiver for improving the hydraulic data transmission in boreholes 112 CHAPTER 11 Conclusion and Outlook 116 11.1 Conclusion 116 11.2 Outlook 120 References 122 List of Figures 129 List of Tables 136 List of Publications 137 List of Patents 138 Appendix- Chapter 7 139 Appendix- Chapter 8 141 Appendix- Chapter 9 142 Appendix- Chapter 10 146

The theoretical discovery of Sanal flow choking in the cardiovascular system (CVS) demands for interdisciplinary studies and universal actions to propose modern medications and to discover new drugs to annul the risk of flow-choking leading to shock-wave generation causing asymptomatic-cardiovascular-diseases. In this chapter we show that when blood-pressure-ratio (BPR) reaches the lower-critical-hemorrhage-index (LCHI) the flow-choking could occur in the CVS with and without stent. The flow-choking is uniquely regulated by the biofluid/blood-heat-capacity-ratio (BHCR). The BHCR is well correlated with BPR, blood-viscosity and ejection-fraction. The closed-form analytical models reveal that the relatively high and the low blood-viscosity are cardiovascular-risk factors. In vitro data shows that nitrogen, oxygen, and carbon dioxide gases are predominant in fresh blood samples of the human being/Guinea-pig at a temperature range of 37–40 °C (98.6–104 °F). In silico results demonstrate the occurrence of Sanal flow choking leading to shock wave generation and pressure-overshoot in CVS without any apparent occlusion. We could conclude authoritatively, without any ex vivo or in vivo studies, that the Sanal flow choking in CVS leads to asymptomatic-cardiovascular-diseases. The cardiovascular-risk could be diminished by concurrently lessening the viscosity of biofluid/blood and flow-turbulence by increasing the thermal-tolerance level in terms of BHCR and/or by decreasing the BPR.

This study addresses a numerical analysis of the thermal-hydraulic response of the secondary side of a steam generator (SG) model with an internal structure to a main steam line break (MSLB) at a pressurized water reactor (PWR) plant. The analysis model is comprised of the SG upper space where steam occupies and the part of the main steam pipe between the SG outlet nozzle and the broken pipe end upstream of the main steam isolation valve. To investigate the effects of the presence of the SG internal structure on the thermal-hydraulic response to the MSLB, the numerical calculation results for the analysis model having a perforated horizontal plate as the SG internal structure are compared to those obtained for a simple analysis model having no SG internal structure. Both analysis models have the same physical dimensions except for the internal structure. The initial operating conditions for both SG models are identical to those for an actual operating plant. To simplify the analyses, it is assumed that steam is constantly generated from the bottom of the SG secondary side space during the blowdown process. As the results, it has been found that the pressure wave significantly attenuates as it passes through the perforated internal structure and as time elapses. This leads to reduction in instantaneous hydraulic load on the internal structure including tubing. However, it is seen that the presence of the internal structure does not affect the transient velocities of steam passing through the SG tube bundle during the blowdown, which are 2 to 8 times the velocities during the normal reactor operation as in the case for the empty SG. Consequently, the present findings should be considered for the design of the steam generator to ensure the reactor safety as such elevated high steam velocities can cause fluidelastic instability of tubes which results in high cycle fatigue failure of the tubes.

Arterial wall stiffness can be associated with various diseases. The stiffness of an artery can be assessed by measurement of the pulse wave velocity (PWV). Usually, PWV is estimated using the foot-to-foot method. However, the foot of the pressure wave is not very clear due to reflected waves. Also, the blood pressure wave generated by the heart is normally a low frequency wave, hence the time resolution is low. PWV is an average indicator of artery stiffness between two measuring locations, therefore, it is not easy to identify local stiffness. In this paper a short external pulse is generated in an artery by the radiation force of ultrasound. The propagation velocity of the pulse wave is measured along the artery. The temporal resolution of this method, which is in the range of microseconds, is much higher than the conventional pressure PWV method, and therefore allows the wave velocity to be measured accurately over a few millimeters.

The pressure waves might be expected in the nuclear reactor systems due to sudden rupture of a pipe, quick opening or closure of a system valve. If generated, they can result in large mechanical loads on the RPV internal structures and pipelines, threating their integrity. This kind of phenomena is an important issue and a limiting accident case for the nuclear power plant safety, which requires extensive analysis to ensure the nuclear power plant safety. To study these phenomena, four PWP (Pressure Wave Propagation) tests have been performed in the PMK-2 test facility in MTA EK. In addition, these tests have been used to assess the capability of the MARS-KS code in simulating the PWP phenomena. Then, an input model representing the PMK-2 test facility was developed to simulate the tests. The MARS-KS simulation results are then compared with the test results. The comparison shows that the MARS code can well simulate the PWP frequencies and the initial pressure peaks as well. After the qualified assessment, the MARS-KS code is then deployed to conduct the sensitivity analysis on the effect of the break size, break time, coolant initial conditions on the PWP phenomena. The sensitivity analysis on the break sizes shows that the pressure wave amplitude is relevant to the break times: the shorter the break opening time is, the faster the pressure. The sensitivity analysis on the break sizes shows that the larger the break size is, the higher the pressure peak is.

When a sudden rupture occurs in high energy lines such as MSL (Main Steam Line) and safety injection line of nuclear power plants, ejection of inner fluid with high temperature and pressure causes blast wave, and may lead to secondary damage of adjacent major components and/or structures. The objective of this study is to assess integrity of containment wall and steam generator due to the blast wave under a postulated high energy line break condition at the MSL piping. In this context, a preliminary analysis was conducted to examine the blast wave simulation using coupled Eulerian-Lagrangian technique. Subsequently, a finite element analysis was carried out to assess integrity of the structures. As typical results, strain and stress values were calculated at the containment wall and steam generator, which did not exceed their failure criteria.

Recent developments of superconductive industry require cryocoolers with cooling power higher than one Watt in the 70–80 K temperature range. High capacity pulse tube cryocoolers assure the cooling power required for operation of superconducting devices. The purpose of this paper is to investigate the influence of the pressure wave generator on high capacity pulse tube cryocooler performance. In this respect the hydrodynamic and thermal behavior of the cryocooler is explained by applying the mass and energy balance equations to different components of the cryocooler cycle. A linear temperature profile is assumed in the regenerator and nodal analysis technique is employed to simulate the tube section behavior numerically. Employing the proposed model the effect of pressure wave characteristics at the inlet boundary, namely, the Stirling type and G-M type pressure inlet on cryocooler performance are investigated. The influence of Pressure amplitude, frequency and swept volume is studied as well.