Double Diaphragms Research Articles

Modelling and design of high quality factor fiber Bragg grating-based geophone

A double-diaphragm acceleration geophone based on Fiber Bragg Grating (FBG) is proposed and demonstrated experimentally in this paper. The proposed geophone is mainly composed of a FBG, double diaphragms, and an inertial mass. Through theoretical analysis and experimental verification, the FBG acceleration geophone has good comprehensive response characteristics. The experimental results obtained indicate that the flat region sensitivity range is from 651.0 to 850.5 pm/G, the corresponding fluctuation is less than 2.20 dB within 1–70 Hz, the cross sensitivity is less than −16.4 dB, and the quality factor is better than 89.1 nm·Hz/G. Compared with the traditional geophones, the proposed geophone has a higher quality factor. Therefore, this type FBG geophone is very good candidate for low-frequency oil and gas exploration.

Evaluation of Shock Tube Retrofitted with Fast-Opening Valve for Dynamic Pressure Calibration

Accurate dynamic pressure measurements are increasingly important. While traceability is lacking, several National Metrology Institutes (NMIs) and calibration laboratories are currently establishing calibration capacities. Shock tubes generating pressure steps with rise times below 1 μs are highly suitable as standards for dynamic pressures in gas. In this work, we present the results from applying a fast-opening valve (FOV) to a shock tube designed for dynamic pressure measurements. We compare the performance of the shock tube when operated with conventional single and double diaphragms and when operated using an FOV. Different aspects are addressed: shock-wave formation, repeatability in amplitude of the realized pressure steps, the assessment of the required driver pressure for realizing nominal pressure steps, and economy. The results show that using the FOV has many advantages compared to the diaphragm: better repeatability, eight times faster to operate, and enables automation of the test sequences.

Broadband and High Sensitivity FBG Accelerometer Based on Double Diaphragms and h-Shaped Hinges

A novel broadband and high sensitivity fiber Bragg grating (FBG) accelerometer is designed and analyzed. The accelerometer is based on a compact structure consisting of double diaphragms and h-shaped hinges. The h-shaped hinge structure is used to break through the restriction between sensitivity and resonance frequency. The FBG accelerometer is demodulated by an interferometric method and test results show that the acceleration sensitivity is 32 dB re pm/g between 1 Hz and 1 kHz, with a fluctuation less than ±3 dB, and the resonant frequency is above 1.6 kHz. The cross-sensitivity is less than -26 dB in the flat frequency of 15μg/√ Hz in a wide frequency range, making it promising range. The sensor shows a high acceleration resolution for cross-well seismic, micro-seismic monitoring and electromechanical equipment vibration monitoring, etc.

Design of Diaphragmless Shock Tube and Research on its Normal Temperature Characteristics

Shock wave is an important physical phenomenon in supersonic airflow. The shock tube is an experimental device that generates shock wave. It generates shock wave by generating a pressure difference between its high-pressure section and low-pressure section. Most researchers in the world use diaphragm shock tubes to generate shock wave, such as single diaphragm structure and double diaphragms structure type shock tubes. Although the type of shock tube can generate an incident shock wave with a wide range of Mach numbers, in the process of producing shock wave and breaking film, there will be broken film fragments interfering with the flow field. And every time the researcher needs to replace the diaphragm after the experiment, the efficiency of the experiment is low. In this paper, a diaphragmless shock tube is designed. The high-speed reciprocating motion of two pistons in the high-pressure section is used to replace the process of membrane rupture. And the normal temperature characteristics of the shock tube are researched.

Gravity-current-induced test gas stratification and its prevention in constrained reaction volume shock-tube experiments

The constrained reaction volume (CRV) method for shock-tube experiments makes it possible to conduct chemical kinetics studies at nearly constant pressure while inhibiting remote ignition. The application of end-wall imaging revealed, however, that CRV experiments are susceptible to vertical stratification at the interface of the test and buffer gases. This work identifies gravity currents as the mechanism leading to the test gas stratification, providing both a theoretical development and experimental investigation of their behavior in a shock tube. Parametric studies are conducted with both the gate valve and stage-filled CRV methods using a novel beam-split laser absorption diagnostic. The speed of gravity-current-induced mixing in both gate valve and stage-filled CRV experiments is shown to depend on the molecular weight matching of the gases and the fill pressure. Mixing velocity in gate valve experiments is shown not to depend on the gate valve speed. In stage-filled experiments, mixing time is seen to be a strong function of the test gas length. Recommended practices for avoiding gravity-current-induced mixing and stratification are described, including gas density matching, utilizing double diaphragms, increasing test gas length in stage-filled experiments, and implementing a gas interface diagnostic.

Congenital pyloric atresia

Background: Congenital pyloric atresia (CPA) is very rare and usually seen as an isolated anomaly, which has an excellent prognosis. CPA can be associated with other anomalies or familial and these are usually associated with other hereditary conditions with poor prognosis. This review is based on our experience with 20 infants with CPA. Patients and methods: This is a review of CPA, highlighting its clinical features; associated anomalies; and aspects of diagnosis, management and outcome. Results: This review is based on our experience with 20 patients with CPA (nine male and 11 female). Their mean birth weight was 2.1 kg (1.1-3.9 kg). Polyhydramnios was seen in 13 (65%) patients. Seven patients were full-term and the remaining 13 were premature. Two were brothers and four were members of the same family. Isolated CPA was seen in seven (35%) patients and 13 had associated anomalies. Epidermolysis bullosa was seen in eight (40%) patients and multiple intestinal atresias in five (25%). Three patients had associated esophageal atresia. Pyloric diaphragm was the most common and seen in 13 patients including double diaphragms in two followed by pyloric atresia with a gap in four and pyloric atresia without a gap in three. All patients did well in the early postoperative period; however, 10 died later giving an overall survival of 40%. Sepsis was the main cause of death. Conclusion: CPA is a very rare malformation that can be familial and inherited as an autosomal recessive. It can either occur as an isolated lesion with an excellent prognosis, or be associated with other anomalies. The overall prognosis of CPA, however, is still poor, and this is due to the frequent-and often fatal-associated anomalies. Keywords: aplasia cutis congenita, congenital pyloric atresia, epidermolysis bullosa, hereditary multiple intestinal atresia

The microscopic anatomy and ultrastructure of the contractile vessel in the sipunculan Themiste hexadactyla (Satô, 1930) (Sipuncula: Sipunculidea)

The microscopic anatomy and ultrastructure of the contractile vessel of the sipunculan Themiste hexadactyla (Sato, 1930) from Vostok Bay (the Sea of Japan) were studied by histological and electron microscope methods. The ultrastructural features of the internal (endothelium) and external (coelothelium) lining of the contractile vessel are described and illustrated. Numerous macromolecular filters, the so-called “double diaphragms,” were found in the external coelothelium facing the cavity of the trunk coelom. This suggests a possible filtration from the tentacular coelom into the trunk coelom though the contractile vessel wall. The microscopic peculiarities of the main tube of the contractile vessel and its numerous lateral branches twining around several internal organs are described in detail. The contractile vessel is polyfunctional: it can act as the main reservoir for the cavity fluid during the withdrawal of the tentacular crown and performs the functions of the distribution system in sipunculans.

Large Frequency Range and High Sensitivity Fiber Bragg Grating Accelerometer Based on Double Diaphragms

A fiber Bragg grating (FBG) accelerometer based on double diaphragms is presented and experimentally demonstrated. Design, fabrication, and optimization of the FBG accelerometer are analyzed. Experimental results indicate that the FBG accelerometer provides broad flat frequency range from 50 to 800 Hz, corresponding sensitivity range from 23.8 to 45.9 pm/G, while the flatness is <;3 dB. Cross-axis sensitivity is <;2.1% of the main-axis sensitivity, dynamic resolution can reach 0.385 mG/√(Hz), and dynamic range is 80 dB. Random error of the FBG accelerometer is analyzed by using Allan variance analysis method, which is promising in cross well seismic exploration.

The microscopic anatomy and ultrastructure of the nephridium of the sipunculan Themiste hexadactyla Satô 1930) (Sipuncula: Sipunculidea)

The microscopic anatomy and ultrastructure of the nephridia of the sipunculan Themiste hexadactyla (Sato, 1930) from the Sea of Japan were studied by the histological and electron microscopic methods. The fine structures of the ciliary funnel, muscular “tongue,” excretory sac, and excretory tube of the nephridium were described. The ultrastructural features of the excretory epithelium, cupola-shaped epithelial infoldings, excretory canals, and muscular layer in the extracellular matrix of the nephridial wall were examined and described in detail. The ultrastructure of the nephridial coelomic epithelium composed of podocytes with long processes and multiciliary cells was also examined and illustrated. Characteristic cell contacts between the processes of podocytes, viz., paired “double diaphragms,” were described and illustrated for the first time.

Congenital pyloric atresia, presentation, management, and outcome: A report of 20 cases

BackgroundCongenital pyloric atresia (CPA) is a very rare anomaly. It is usually seen as an isolated condition with excellent prognosis. Few cases are familial. These are usually associated with other hereditary conditions and have a poor prognosis. This is a review of our experience with 20 patients with CPA outlining aspects of diagnosis, associated anomalies and management. Patients and methodsThis is a retrospective analysis of 20 cases seen over a 22year period (December 1990 to December 2012). Their records reviewed for: age, sex, presentation, prenatal history, associated anomalies, investigations, treatment, operative findings and the outcome. Results20 cases (9 Males, 11 Females) were treated. 7 patients were full term and the remaining 13 were prematures. Their mean birth weight was 2.1kg (1.1kg to 3.9kg). Polyhydramnios was seen in 13 patients (65%). Two were brothers and four were members of the same family. Isolated CPA was seen in 7 (35%); 13 had an associated conditions: epidermolysis bullosa (EB) in 8 (40%) and multiple intestinal atresias (MIA) in 5 (25%). Three patients had associated esophageal atresia. All were operated on except two who died early due to unrelenting sepsis. The variety of pyloric atresias encountered were as follows: pyloric diaphragm in 13 including double diaphragms in 2, pyloric atresia with a gap in 4 and pyloric atresia without gap in 3. Ten died postoperatively giving an overall survival of 40%. ConclusionsCPA is a very rare condition. Isolated CPA carries a good prognosis. Association of CPA with other familial and congenital anomalies like EB and MIA carries a poor prognosis.

Flow rate self-sensing of a pump with double piezoelectric actuators

According to the method of segmenting electrode, the flow rate self-sensing of a conventional piezoelectric pump with the actuators of double diaphragms is presented in this paper. The novel pump is characterized by the simultaneous function of fluid transportation and the flow rate self-testing through only one piezoelectric element. The analysis indicates that direct and converse piezoelectric effect can be concurrently applied to obtain the simultaneous function through dividing the electrode of the piezoelectric element into driving unit and sensing unit. With two commercialized segmented-electrode piezoelectric diaphragms, a prototype pump is fabricated with the size of 65mm×40mm×12mm and tested according to the frequency characteristics at a fixed driving voltage and the driving voltage characteristics at a fixed frequency. The results show that sensing voltages of diaphragms are increased or decreased with the change of the flow rate as a function of frequency. When the flow rate reaches the maximum value of 45.98ml/min at 15Hz, outlet/inlet sensing voltages also reach maximum values of 6.80Vpp and 19.4Vpp, respectively. It demonstrates that the pump itself could accurately reflect the optimal frequency through monitoring outlet/inlet sensing voltages. The testing results indicate the good linear relationship between outlet/inlet sensing voltages and the flow rate as a function of driving voltage. Therefore, both theoretical analysis and experiments have proved that flow rate self-sensing can be realized for the piezoelectric pumps with double actuators through segmenting their electrode. Moreover, if any electrode of double piezoelectric actuators is segmented, the pump can obtain the complete self-sensing function.

Congenital double duodenal diaphragms in an infant

Duodenal stenosis usually occurs in isolation and has a variable presentation in infancy due to partial obstruction. An unusual case of congenital double duodenal diaphragms in an infant presenting as failure to thrive has been described and pertinent literature has been reviewed herein. Excision of webs with double Heineke-Mikulicz closure was performed.

Effect of forming temperature on the quality of hot diaphragm formed C-shaped thermosetting composite laminates

Hot diaphragm-forming process is a promising technology for production of angle-shaped thermosetting composites with high efficiency and consistent quality. This technique can be used to form prepreg laminates with abrupt or complex structures before final cure in an autoclave. In this work, the mechanism of the forming process using double diaphragms for carbon fiber/epoxy resin prepreg laminate with C-shaped structure was discussed, and the effect of the forming temperature on the quality of formed laminate was investigated using a designed hot diaphragm-forming device. A testing system was set up to evaluate the frictional resistance of prepreg at different temperatures. The results indicate that a proper forming temperature is essential for quality control of the process and there is a close relationship between prepreg properties and forming qualities of parts.

Reinforced piezoresistive pressure sensor for ocean depth measurements

Depth/pressure measurements in the ocean are of utmost importance to better understand the ocean processes, for maritime security and for tsunami wave detection. In this work, a reinforced piezoresistive pressure sensor with double diaphragms and Wheatstone bridges is proposed to achieve higher sensitivity, wider operating range and temperature compensation in ocean depth measurements. The reinforced design showed higher sensitivity (by 10–15%) and wider operating pressure capability (by 2–2.2 times) compared to the conventional single diaphragm piezoresistive design. The reinforced sensor design was validated by measuring the performance of a two-element pressure sensor, which showed sensitivity between 0.13 and 0.74 mV/(V psi) and a full scale span increased by approximately two times.

Congenital pyloric atresia and associated anomalies

Congenital pyloric atresia (CPA) is a very rare condition that was first described by Calder in 1749. Commonly, CPA occurs as an isolated lesion, which has an excellent prognosis, but it can also be seen in association with other malformations, which can have a negative impact on the final outcome. The medical records of all patients with the diagnosis of CPA treated at our hospital were retrospectively reviewed for: age at diagnosis, sex, presenting symptoms, history of polyhydramnios, diagnosis, associated anomalies, operative findings, treatment and outcome. Eleven cases with the diagnosis of CPA were treated at our hospital. There were five males and six females. Seven were products of full term normal vaginal delivery and the remaining four were prematures. Their birth weights ranged from 1.2 to 3.9 kg (mean 2.2 kg). Polyhydramnios was seen in seven (63.6%). Associated anomalies were seen in six (54.5%). These included epidermolysis bullosa (EB) in three, hereditary multiple intestinal atresias (HMIA) in two including a duplication cyst in one of them, esophageal atresia in one, Down's syndrome in one, congenital heart disease in one, cleft palate in one and aplasia cutis congenital (ACC) in one. Intraoperatively, five had pyloric diaphragms, in two of them there were double diaphragms, three had pyloric atresia with a gap between the two ends and two had pyloric atresia with no gap. One of them had duodenal perforation as well as ileal perforation. The patients with pyloric diaphragms had excision of diaphragms and Heineke-Mickulicz pyloroplasty. Four of the other five patients had gastro-duodenostomy. One of them also had duodeno-jejunostomy due to associated distal duodenal atresia and excision of duplication cyst. The patient with duodenal and ileal perforation and because of the marked distension of the duodenum had reduction duodenoplasty, gastroduodenostomy, and duodeno-jejunostomy. The area of ileal perforation was resected and end-to-end anastomosis was done after correction of the associated malrotation. One patient with associated esophageal atresia had gastrostomy and gastrojejunostomy. Post-operatively, all did well initially, but subsequently, six of them died giving an overall survival of 45.5%. Sepsis was the cause of death in all of them. CPA is very rare and when it occurs in isolation it has a good prognosis. The association of CPA with HMIA is universally fatal. CPA in association with EB has a high mortality but there are encouraging results with the use of steroids and phenytoin. Sepsis continues to be the main cause of death and an associated combined immunodeficiency should be excluded.

New Generation of Synthetic Jet Actuators

I N the last 20 years, much attention has been given to developing microfluidic systems [1]. Among them, synthetic-jet actuators (SJA) have been intensely studied recently [2]. Synthetic-jet actuators have many potential applications such as jet vectoring [3,4], boundary-layer control [5,6], combustion control [7], and micro-pumps [8], etc. A synthetic-jet actuator is a zero net mass flux device. Figure 1a shows a typical structure of an existing SJA, which is composed of an exit slot (or orifice) and a diaphragm (or double diaphragms [9]) mounted to enclose a volume of fluid in a cavity. Piezoelectric (PZT) diaphragms are used in most minior microSJAs because of their size, rapid time response, and relatively low power consumption. The PZT-driven SJA also fits within the microelectromechanical system (MEMS) discipline and can be coupled with MEMS sensors, control and logic electronics into a single very lightweight and compact device. Unfortunately, the pressure loading limits to obtain a small deflection of the PZTdiaphragm on the existing SJA requires a high power to drive the PZT-diaphragm when the pressure differential between the base flow (to be controlled by the SJA) and the environment is large. This limits applications of the SJA. In addition, the diaphragm of the existing SJA (as shown in Fig. 1a) has one surface exposed to the fluid drawn from the base flow and the other surface exposed to the environment, which indicates that half of the radiation energy of the vibrating diaphragm is wasted in the environment. Keeping the advantages of a PZT-driven SJA,while resolving themajor problems of pressure loading and energy inefficiency, is the main impetus for designing a new generation SJA. A newSJA prototype is schematically shown in Fig. 1b. It consists of two cavities, a PZT-diaphragm, two exit slots, and a slide block (SB). In the new SJA concept, two adjacent jets are established under the two exit slots and are driven by the motion of the same PZTdiaphragm. The slide block regulates the two jets (as shown in Figs. 1b–1d), and then two adjacent jets merge into a single, larger synthetic jet. In this Note, numerical simulations are conducted to study the new SJA. We include a discussion focused on the novelty and merits of the new SJA in comparison with the existing SJAs.

2313 薄膜金属ガラスを用いた集積形ERマイクロアクチュエータ(OS8-3 アクチュエータシステム(3))

A novel 3-DOF ER micractuator using thin film metallic glass was proposed and fabricated. The actuator consists of 3-DOF stacked diaphragms and a micro ER valves unit. By internal stress elimination in the supercooled liquid region and wide elastic range of thin film metallic glass, the diaphagms have capability to generate large displacement. In this paper, as a simple diaphagm configulation for larger displacement, a double dome diaphragm was obtained based on FEM analysis. Through fabrications using MEMS process, process conditions to fabricate the double dome diaphragms were experimentally clarified. Also, the micro ER valves unit large model was fabricated and the valve control characteristics were experimentally clarified.

A thickness-shear quartz resonator force sensor with dual-mode temperature compensation

An AT-cut thickness-shear quartz crystal resonator (QXR) has been used as a force sensing and self-temperature-sensing (STS) element to develop a digital output force sensor. The QXR is fixed in a two-line mounting configuration in a cylindrical metal shell by double diaphragms, through which a diametric force proportional to the unknown force is applied to the QXR. The double diaphragms improve the reliability and the mechanical stability of the sensor significantly. In order to increase the measurement range and the sensitivity, the energy trapping-based QXR is cut to a symmetrical, incomplete circular shape to decrease stress concentration. Because operating the QXR in dual-mode excitation allows the separation of force change effects from temperature change effects, force measurement and STS are accomplished simultaneously with the same QXR. The structure and the configuration are optimized with theoretical analysis and FEM. The dual-mode STS and temperature compensation are described in detail, as well as a trimming method to reduce activity dips of AT-cut QXRs.

Microscopic anatomy and ultrastructure of a Polian vessel in the sipunculan Thysanocardia nigra Ikeda, 1904 from the Sea of Japan

The microscopic anatomy and ultrastructure of a Polian vessel have been studied in the sipunculan Thysanocardia nigra Ikeda, 1904 from the Sea of Japan using the methods of histology and electron microscopy. We describe ultrastructural features of the inner and outer coelothelium, which is constructed of podocytes and multiciliary cells. Between the processes of the podocyte cells, we found double diaphragms that are considered characteristic macromolecular filters. We conclude from an analysis of the ultrastructural features of the vessel wall that coelomic fluid may be filtered from the tentacular coelom to the trunk coelom via the wall of the Polian vessel.

The regulation of natural killer–mediated swine endothelial cell lysis by HLA-G (G1 and G3)

Congenital pyloric atresia (CPA) is a very rare anomaly. It is usually seen as an isolated condition with excellent prognosis. Few cases are familial. These are usually associated with other hereditary conditions and have a poor prognosis. This is a review of our experience with 20 patients with CPA outlining aspects of diagnosis, associated anomalies and management.This is a retrospective analysis of 20 cases seen over a 22 year period (December 1990 to December 2012). Their records reviewed for: age, sex, presentation, prenatal history, associated anomalies, investigations, treatment, operative findings and the outcome.20 cases (9 Males, 11 Females) were treated. 7 patients were full term and the remaining 13 were prematures. Their mean birth weight was 2.1 kg (1.1 kg to 3.9 kg). Polyhydramnios was seen in 13 patients (65%). Two were brothers and four were members of the same family. Isolated CPA was seen in 7 (35%); 13 had an associated conditions: epidermolysis bullosa (EB) in 8 (40%) and multiple intestinal atresias (MIA) in 5 (25%). Three patients had associated esophageal atresia. All were operated on except two who died early due to unrelenting sepsis. The variety of pyloric atresias encountered were as follows: pyloric diaphragm in 13 including double diaphragms in 2, pyloric atresia with a gap in 4 and pyloric atresia without gap in 3. Ten died postoperatively giving an overall survival of 40%.CPA is a very rare condition. Isolated CPA carries a good prognosis. Association of CPA with other familial and congenital anomalies like EB and MIA carries a poor prognosis.