Traditional Diaphragm Research Articles

Supercapacitor-isolated water electrolysis for renewable energy storage

This study addresses a significant technological challenge in hydrogen production through electrolysis: the issue of gas crossover across the diaphragm between the cathode and anode, particularly under variable power conditions associated with renewable energy sources. We introduce a novel supercapacitor-isolated alkaline water electrolysis system utilizing a carbon-based supercapacitor sheet approximately 1 mm thick as an alternative to traditional diaphragms, effectively reducing gas crossover. At 25 °C and in 2.0 M KOH, our electrolysis system achieved a high current density of 0.736 A cm−2 for hydrogen evolution at 2.0 V, which was maintained at 0.023 A cm−2 even when the voltage was reduced to 0.9 V. Notably, the concentration of hydrogen to oxygen (HTO) remained low at 0.42 vol% with a current density of 0.01 A cm−2, surpassing the 28.5 vol% observed with a traditional diaphragm under similar conditions. At 70 °C, the electrolysis system exhibited an average hydrogen evolution rate of 0.952 A cm−2, with a specific energy consumption of 4.786 kWh Nm−3 (H₂) and a Faradaic efficiency of 99.5 %. Following a 55-day test under near-industrial conditions, the capacitive electrode demonstrated exceptional durability. These results represent a significant advancement in decoupled water electrolysis, indicating that the direct utilization of renewable energy for hydrogen production is feasible.

Experimental Study on the Horizontal Bearing Characteristic of a Strip-Walled Underground Diaphragm Wall

Researching and developing a new type of diaphragm wall foundation can solve the probl em that the traditional diaphragm wall structure may not meet the high standards of safety and stability of underground structures in some specific engineering environments. This paper focuses on the horizontal bearing characteristic of a new form of foundation, a strip-walled underground diaphragm wall, through a series of model tests. In the tests, nine plexiglass models with different section sizes, wall spacings and wall heights, as well as loading strategies (horizontal loads along and against the wall in the model), were conducted. The influence of the above factors on the horizontal bearing performance of the foundation and the soil resistance distribution around the wall was studied. The results show that when the horizontal load applied along the wall is greater than 50 N, the growth rate of total displacement at the top of the wall gradually decreases; when a horizontal load is applied against the wall, with a uniform change in wall height, the optimal wall spacing is 11 cm. When the same displacement occurs, the bearing performance of the model under the former loading strategy is generally 10% higher than that under the later loading strategy. In addition, the depth where the maximum bending moment along the wall occurred gradually moves downward with the increase in horizontal load, and the increase in wall spacing and wall height has a positive effect on the horizontal bearing characteristic. With the application of load, the maximum bending moment of the wall will gradually decrease along the depth. The increase in wall spacing and wall height can improve the overall flexural stiffness and horizontal bearing performance of the foundation. Lastly, the group wall effect coefficient, β, is put forward, and a simplified formula for calculating the horizontal bearing capacity of a strip wall foundation is proposed. In the formula, β is negatively correlated with the buried depth of the wall and positively correlated with the distance between the walls, and its coefficient is greater than 1.

Research of a new hot-rolled connector connection to composite walls

The composite members in steel residential buildings often possess small sections and have high restrictions on the indoor space extrusion of structural components, and then traditional diaphragm type and internal or exterior stiffener connections are hardly applied. A new hot-rolled connector connection was proposed, which used the flange-to-web arch transition of hot-rolled steel beams as the intermediate connector. The smooth section transition of the connector at the column face junction can reduce the stress concentrations and premature fracture potentials of connections between H-shaped beams and small-size composite walls or CFST columns in steel residential buildings. Four hot-rolled connector connections with different connector designs and beam sizes were tested under cyclic loads, and the seismic performances and working mechanisms were investigated. Refined finite element simulations were performed to indicate the load transfer path and load sharing mode in the connection. Results indicated that the proposed connection displayed plump hysteretic relations and satisfactory energy dissipation ability. The strengthened connectors succeeded in inducing the high plasticity away from the wall or column face. The bottom beam flange to connector butt weld was prone to fracture. The HTC connection with a long HTC connecting beam and the two bolt-row construction as the web connection was suggested.

Rotordynamic analysis and leakage performance study of a hole diaphragm labyrinth seal using the CFD method

Improving rotor stability and reducing leakage at various working parts of gas turbines is an important topic that experts and scholars have always pursued. In this article, a new type of hole-diaphragm-labyrinth seal (HDLS) structure is obtained by introducing an additional damping source. The HDLS structure is built by the traditional diaphragm labyrinth seal (DLS) with a single hole added to the diaphragm. The simulation under different working conditions of three different seal structures is carried out by ANSYS Fluent. Subsequently, the tangential force under different whirl frequencies was obtained. Meanwhile, the empirical parameters in Childs’ model of the dynamic performance of rotor-seal structures were obtained. The results show that the HDLS achieved a 71.4% improvement in the direct stiffness coefficient and a 71.8% improvement in the direct damping coefficient of the traditional labyrinth seal. The leakages of HDLS at different rotation speeds were lower than those of DLS by 1.53% and LS by 3.64%. The HDLS can be comprehensively considered the most promising seals among LS, DLS, and HDLS not only by stability but also by mass flow leakage in the rotor system.

Calculation of micropiles and anchors to reinforce a slope in emergency situations: application in Málaga, Spain

The importance of preserving affected buildings and infrastructures to landslides is a critical problem in some areas. A system that is less invasive than traditional concrete diaphragm walls or piles is proposed in this work. The proposed system consists of the execution of a row of micropiles and anchors with a methodology of calculation based on the Spencer's limit equilibrium method. Micropiles, as a possible measure for rapid reinforcement of a slope, are always designed in groups. Slope stability analysis automatically employs the pore pressures calculated in groundwater analysis. After a landslide is reinforced, the stability coefficient of the landslide can be increased from 0.907 to 1.504 with the application of our developed model in the application example in Málaga, southern Spain. The results of the proposed model show that a row of micropiles and anchors can effectively enhance the landslide stability in emergency cases. The results and conclusions are helpful in providing a theoretical foundation to clarify the failure mechanism and provide a reference for the design of micropiles and anchors for landslide events.

The Development of a New Piezoresistive Pressure Sensor for Low Pressures

This paper presents the design methodology and fabrication process of a novel piezoresistive pressure sensor with a combined cross-beam membrane and peninsula (CBMP) diaphragm structure for micropressure measurements. The sensor is then analyzed through various experiments. The sensor is primarily designed based on the optimized sensitivity, and a finite-element method is used to predict the stresses that are induced in the piezoresistors and the deflection of the membrane under different pressures. Compared to other traditional diaphragm types, a significant increase in sensitivity can be achieved by the proposed sensor, and the membrane deflection and nonlinearity error considerably decrease. The sensor fabrication process is performed on an n-type single-crystal silicon wafer, and photolithography is used with five masks to fabricate the sensing elements. Additionally, piezoresistors are formed by boron implantation. The experimental results indicate that the fabricated sensor with the CBMP membrane yields a high sensitivity of 25.7 mV/kPa and a low nonlinearity of −0.28% full-scale span for a pressure range of 0–5 kPa at room temperature.

Research on the Design Parameters of the Diaphragm Based on the Torsional Static-characteristics

In view of the diaphragms of traditional diaphragm coupling in conditions of large centrifugal force, the hub or rim with prominent stress concentration, the effective size of the elastic film is small, and the tangential load distribution uneven by the bolt connection, a closed diaphragm coupling is presented, it is connected by interference fit, and eliminates the membrane disc rim, increases the effective size, improves centrifugal action. Under the static torsion loading conditions, deformation and stress distribution with the variation of membrane disc thickness, taper, double curvature and radial dimensions of the diaphragm having the linear surface, cone surface and hyperbolic surface are studied. The stress and deformation characteristics of three kinds of disc surfaces are summarized by analogy, and the design rules and selection principles of various types of diaphragm for practical application are obtained.

A Novel Approach for Enhancement of Automobile Clutch Engagement Quality Using Mechatronics Based Automated Clutch System

In automated manual clutch (AMC) a mechatronic system controls clutch force trajectory through an actuator governed by a control system. The present study identifies relevant characteristics of this trajectory and their effects on driveline dynamics and engagement quality. A new type of force trajectory is identified which gives the good engagement quality. However this trajectory is not achievable through conventional clutch control mechanism. But in AMC a mechatronic system based on electro-hydraulic or electro-mechanical elements can make it feasible. A mechatronic system is presented in which a mechatronic add-on system can be used to implement the novel force trajectory, without the requirement of replacing the traditional diaphragm spring based clutch in a vehicle with manual transmission.

Differential pressure sensor using a piezoresistive cantilever

This paper reports on a differential pressure sensor using a piezoresistive cantilever with the dimensions of 125 µm×100 µm×0.3 µm. The sensor has a higher sensitivity than a traditional diaphragm sensor because of the three free edges of the cantilever. The measured results indicated that the fabricated cantilever bent according to theory when differential pressure was applied. The sensitivity and resolution of the differential pressure were 3.2×10−4 Pa−1 and 0.02 Pa from −20 Pa to 20 Pa, respectively.

Flexible Pressure Sensors: Modeling and Experimental Characterization

Flexible capacitive pressure sensors fabricated with nanocomposites were experimentally characterized and results compared with simulations from analytical modeling. Unlike traditional diaphragm silicon pressure sensors, the flexible nanocomposite sensors present a linear response over a large pressure range due to the changes in the volume of the dielectric that cause the pressure inside the dielectric cavity to change. Several devices with different geometries were used and the model results compare well with the experimental data. Sensitivities ranging from 2.5-20 fF/kPa were obtained and the devices dynamic response show a dual behavior, i.e., response time of the sensor during a pressure decreasing step is lower than for a pressure increasing step. This comportment is explained by the viscoelastic behavior of the PDMS-based nanocomposites used for fabrication of the capacitive sensor electrodes.

A novel diaphragm micropump actuated by conjugated polymer petals: Fabrication, modeling, and experimental results

Micropumps have promising applications in biomedical devices and micro total analysis systems. Conjugated polymer actuators provide an important potential mechanism for realizing micropumps because of their amenability to miniaturization and low actuation voltages. In this paper we present a novel, conjugated polymer petal-actuated diaphragm micropump, which is in contrast to the typical diaphragm design of using a single piece of soft actuation material clamped at all edges. We show through analysis and experiments that the new design, by alleviating the edge constrains, can provide significantly larger diaphragm deformation and consequently higher flow rate. A physics-based, control-oriented model is developed to predict the diaphragm deformation and the flow rate given the actuation voltage input. Experiments conducted on a polypyrrole (PPy)-actuated micropump, fabricated through PDMS-based MEMS processes, have validated the dynamic model. A maximum flow rate of 1260 μ L / min is achieved for the petal-actuated diaphragm pump under an actuation voltage of 4 V, while in comparison, the pump with traditional diaphragm design generates no observable flow under the same voltage.

Overcoming Scaling Problems in Miniaturized Silicon Microphones

In 2008 it is projected that global demand for mobile devices will reach 1.2 billion units. Compared to electronic gadgets from 2002 when 430 million cell phones were sold world wide, these devices are smaller, have more features, and will generally be priced lower. In order to keep up with designers and manufacturers who relentlessly pursue efficient use of space at lower cost, it is required that component manufacturers pursue the same goal. For a microphone manufacturer like Knowles, this led to the introduction of world's first commercialized surface-mountable microphone, the SiSonic™ microphone, in 2002. MEMS technology is used to manufacture the complex miniaturized components used in SiSonic™ microphone. Straightforward miniaturization of microphone diaphragms made of silicon, a common material in MEMS technology, instead of traditional diaphragm materials leads to poor performing microphones. To take advantage of MEMS technology without sacrificing microphone performance we developed the free plate technology. In this presentation we discuss the use of free plate technology to overcome difficulties related to miniaturization in MEMS.

Acceptability of the vaginal diaphragm among current users.

Interest in the diaphragm has been growing, in part because it is a female-controlled method that might protect against HIV and other sexually transmitted diseases (STDs). A better understanding of diaphragm acceptability is needed. In 2001-2002, female members of a managed care organization were interviewed by telephone. The 215 participants, aged 19-49, who reported diaphragm use during the past three months were asked about their experience with the method and background characteristics. Characteristics associated with women's satisfaction with and consistent use of the diaphragm were identified through multiple logistic regression analysis. Most participants had a low risk for HIV and other STDs. The mean duration of diaphragm use was 8.5 years. Although only 42% of participants reported consistent use in the past three months, most were satisfied with the method (79%) and planned to use it at next vaginal intercourse (85%). Satisfied users had significantly higher diaphragm use self-efficacy and more positive perceptions of the method than those not satisfied. Consistent use was significantly associated with older age and having had some college education rather than none. More than half of women cited dissatisfaction with previous methods (72%) and provider recommendation (61%) as moderately to extremely important in their decision to begin diaphragm use. When asked what they would change about the diaphragm, 32% mentioned concerns related to inserting or removing it. From an acceptability point of view, the diaphragm appears to be a viable candidate for a female-controlled method for prevention of HIV and other STDs. Our findings have important implications for the reintroduction of the traditional diaphragm and development of new diaphragm-like products.

Acceptability of the Vaginal Diaphragm Among Current Users

CONTEXT: Interest in the diaphragm has been growing, in part because it is a female‐controlled method that might protect against HIV and other sexually transmitted diseases (STDs). A better understanding of diaphragm acceptability is needed.METHODS: In 2001–2002, female members of a managed care organization were interviewed by telephone. The 215 participants, aged 19–49, who reported diaphragm use during the past three months were asked about their experience with the method and background characteristics. Characteristics associated with women's satisfaction with and consistent use of the diaphragm were identified through multiple logistic regression analysis.RESULTS: Most participants had a low risk for HIV and other STDs. The mean duration of diaphragm use was 8.5 years. Although only 42% of participants reported consistent use in the past three months, most were satisfied with the method (79%) and planned to use it at next vaginal intercourse (85%). Satisfied users had significantly higher diaphragm use self‐efficacy and more positive perceptions of the method than those not satisfied. Consistent use was significantly associated with older age and having had some college education rather than none. More than half of women cited dissatisfaction with previous methods (72%) and provider recommendation (61%) as moderately to extremely important in their decision to begin diaphragm use. When asked what they would change about the diaphragm, 32% mentioned concerns related to inserting or removing it.CONCLUSIONS: From an acceptability point of view, the diaphragm appears to be a viable candidate for a female‐controlled method for prevention of HIV and other STDs. Our findings have important implications for the reintroduc‐tion of the traditional diaphragm and development of new diaphragm‐like products.

Acceptability of the Vaginal Diaphragm Among Current Users

CONTEXT: Interest in the diaphragm has been growing, in part because it is a female-controlled method that might protect against HIV and other sexually transmitted diseases (STDs). A better understanding of diaphragm acceptability is needed. METHODS: In 2001–2002, female members of a managed care organization were interviewed by telephone. The 215 participants, aged 19–49, who reported diaphragm use during the past three months were asked about their experience with the method and background characteristics. Characteristics associated with women's satisfaction with and consistent use of the diaphragm were identified through multiple logistic regression analysis. RESULTS: Most participants had a low risk for HIV and other STDs. The mean duration of diaphragm use was 8.5 years. Although only 42% of participants reported consistent use in the past three months, most were satisfied with the method (79%) and planned to use it at next vaginal intercourse (85%). Satisfied users had significantly higher diaphragm use self-efficacy and more positive perceptions of the method than those not satisfied. Consistent use was significantly associated with older age and having had some college education rather than none. More than half of women cited dissatisfaction with previous methods (72%) and provider recommendation (61%) as moderately to extremely important in their decision to begin diaphragm use. When asked what they would change about the diaphragm, 32% mentioned concerns related to inserting or removing it. CONCLUSIONS: From an acceptability point of view, the diaphragm appears to be a viable candidate for a female-controlled method for prevention of HIV and other STDs. Our findings have important implications for the reintroduc-tion of the traditional diaphragm and development of new diaphragm-like products.

Diversity and developmental regulation of extraocular muscle: progress and prospects.

The developmental regulation of skeletal muscle phenotypes has attracted much attention from cell and molecular biologists. Myogenesis serves as an excellent model of the interaction of genetic and epigenetic events in determining definitive adult characteristics. The muscles that are responsible for eye movements are among the most structurally and functionally diverse mammalian skeletal muscles. Despite these unique attributes, the extraocular muscle has been studied less extensively than the traditional limb and diaphragm models. This review explores current concepts regarding the development of these muscles. Proper interocular alignment and coordination of eye movements are essential for normal vision in the adult. Moreover, coordinated oculomotor function during the perinatal period is critical for the normal development of the visual system. Therefore, a thorough understanding of the sequence of events and mechanisms that regulate extraocular muscle development and maldevelopment is vital. Studies related to myoblast origin and differentiation and to the role of genetic versus environmental factors in shaping and maintaining adult extraocular muscle phenotype are reviewed. Prospects for understanding the cellular and molecular mechanisms that regulate the heterogeneity and plasticity of these muscles also are discussed.