Diaphragm Membrane Research Articles

Study of operating modes of a double-chamber diaphragm milk pump

Diaphragm (membrane) pumps refer to a class of devices with a reciprocating movement of the working body that are widely used in various industrial technologies and in everyday life. In agricultural production, these pumps are used in the production line of milking installations and for creating a vacuum in individual milking machines. The most important distinguishing feature of a diaphragm pump is the minimum mechanical effect on the pumped product due to the excluded action of centrifugal forces, which in turn excludes mechanical impact and foaming. Therefore, they are mainly used for delicate pumping of products, in particular milk. Another important feature of the pump design is its tightness that serves as a reliable barrier to isolate the working and external environments. A significantly smaller number of rubbing parts in comparison with centrifugal pumps ensures higher reliability and minimum maintenance. Analysis of modern designs of diaphragm pumps showed that their productivity and operational reliability can be improved as follows: two-chamber version; the increased usable volume of the chamber due to the diaphragm structuring; electric drive of the working body. The team of authors substantiated the design of a two-chamber milk pump with an electromagnetic drive, substantiated its supply to ensure stable operation of the milking installation throughout the entire milking time, and calculated the effect of the structured diaphragm diameter on the pump flow. The laboratory bench of the Department of Machines and Technologies of Agro-industrial Complex, Stavropol State Agrarian University, was used for experimental studies, and the estimated payback period for the developed pump design was found not to exceed 1.2...1.5 years.

Cerium Oxide-Polysulfone Composite Separator for an Advanced Alkaline Electrolyzer.

The intermittent and volatile nature of renewable energy sources threatens the stable operation of power grids, necessitating dynamically operated energy storage. Power-to-gas technology is a promising method for managing electricity variations on a large gigawatt (GW) scale. The electrolyzer is a key component that can convert excess electricity into hydrogen with high flexibility. Recently, organic/inorganic composite separators have been widely used as diaphragm membranes; however, they are prone to increase ohmic resistance and gas crossover, which inhibit electrolyzer efficiency. Here, we show that the ceria nanoparticle and polysulfone composite separator exhibits a low area resistance of 0.16 Ω cm2 and a hydrogen permeability of 1.2 × 10–12 mol cm–1 s–1 bar–1 in 30 wt% potassium hydroxide (KOH) electrolyte, which outperformed the commercial separator, the Zirfon PERL separator. The cell using a 100 nm ceria nanoparticle/polysulfone separator and advanced catalysts has a remarkable capability of 1.84 V at 800 mA cm−2 at 30 wt% and 80 °C. The decrease in the average pore size of 77 nm and high wettability (contact angle 75°) contributed to the reduced ohmic resistance and low gas crossover. These results demonstrate that the use of ceria nanoparticle-based separators can achieve high performance compared to commercial zirconia-based separators.

A high sensitive graphene piezoresistive MEMS pressure sensor by integration of rod beams in silicon diaphragm for low pressure measurement application

MEMS piezoresistive pressure sensors are most widely explored for various applications such as industrial, automotive and medical field. Each application covers a wide operating range from very low pressure to the higher pressure. In this paper a novel structure is designed by introducing the local stiffness in the diaphragm membrane for low pressure measurement. Rod beams at the diaphragm with combination of graphene piezoresistors, improves overall performance of the pressure sensor in terms of sensitivity. At higher temperature and higher pressure, a noticeable sensitivity is achieved which is compared to the previous design of graphene pressure sensor without rod beam structure. At room temperature (25 °C), sensitivity of pressure sensor with rod beam structure is 6.28 mV/psi. At 30 °C, the sensitivity is 58% higher than sensitivity of pressure sensor without rod beam structure for low-pressure specific range.

Evaluation Method of Electrocatalysts for Oxygen Evolution Reaction in Alkaline Media

Introduction Alkaline water electrolysis (AWE) produces hydrogen without any carbon dioxide emission with renewable electric power supply. Anode of the AWE is usually used Ni based material which is stable under steady electrolysis. To improve the AWE performance, the anode overpotential has to be reduced under fluctuating electricity from renewable energy that enhances deterioration of the anode. So, durable effective electrocatalyst is needed to enhance the energy conversion efficiency. Currently, most of the transition metal-based OER composite catalysts reported are powders, which are subsequently coated onto conductive substrates with the aid of Nafion. 1, 2)The utilization of binder decreases interfaces of catalyst/electrolyte and catalyst/catalyst, and reduces observed electrocatalytic activity.3) In addition, they have rarely been investigated under practical current density and potential region, because generated babble destroys bonded catalyst layer structure. In this study, as a new powder electrocatalyst evaluation method, we have investigated the OER activity of LaNiO3 using an electrolyzer with the structure to fix the powder on a diaphragm membrane, and compared the OER activity with that of the electrode prepared by CIP and sintering method which could be evaluated even in the high current density region.4) Experimental Figure 1 shows the schematic drawing of 1cm2 electrolyzer with independent effective area contact control system.It makes setup to press the catalyst supported portion onto the membrane. Ag/AgCl references placed on the membrane of seal area contacted with electrolyte. Cell components are made of Ti with Pt plating for anode side, and PEFCs grade glassy carbon for cathode side, respectively. Anode backing was porous Ti or Ti rib with Pt plating to reduce contact resistance. Anode and cathode electrocatalyst were LaNiO3 and PtRu/C (TKK), respectively. The 0.8~1.2 mgcm-2-metal of anode catalyst was coated onto Zirfon membrane, and the 0.5 mgcm-2-metal of cathode catalyst was coated onto a carbon paper (35BC, SGL) as cathode electrode. 7M KOH was circulated as the electrolyte. After pretreatment, the OER performance was evaluated Chronoamperometry (CA) and slow scan voltammetry (SSV). The loading amount of LaNiO3 was analyzed by XRF before and after electrochemical measurements. Results and discussion Figure 2 shows the separation of the measured chronoamperogram using rib anode backing to charging the faradic currents.5) The blue curve in Figure 2 is the measured current from the CA at 1.6 V, and it can be separated as the charging current of green line, which numerical simulated from I charging = (ΔE/R s)exp(-t/R s C d) [eq. 1] and the faradic current of red line that was difference between measured current and charging current. For the measured current, the initial value of the measured current is dominated by the charging current. Therefore, the charging current was determined by extrapolation with the initial measured current and the eq. 1. After a few milliseconds, the current would be dominated by the oxygen evolution reaction and decreased with time. The decrease would be affected by mass transfer suppressed by oxygen babble. Figure 3 shows the faradic current as a function of the square root of time (red). The current increased in the initial period, and decreased. By extrapolation to time 0 for the linear region of current decrease (black line), the mass transfer free faradic current at time 0 could be found. The intercept is defined as the kinetic current, I k,. Figure 4 shows polarization curves of the I k from the CA and the SSV using the porous anode backing of this work with the CIP and sintering method and the ink coating method.6, 7) In this figure, the apparent OER activity of the I k of the CA method and the CIP and sintering method were higher than others and the current was stable in high current density. So, the I k of the CA method would be suitable method to determine OER activity of powder catalyst, because the CIP and sintering method is limited to the materials that allows sintering process. Acknowledgment This study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). Reference 1) A. Grimaud et al. Nat commun, 4, 2439 (2013) 2) M. S. Burke et al. Chem. Mater, 27, 7549 (2015) 3) J. Ji et al. ACS Nano, 7, 6237 (2013). 4) Y. Tsukada et al. of the 42th Meeting of Electrolytic Technology, 86, Japan (2018/11) 5) Y. Bao et al. Electrocatalysis, 10, 184 (2019) 6) W. Zhou et al. Mater. Horiz, 2, 495 (2015) 7) R. Liu et al. Nano Energy, 12, 115 (2015) Figure 1

Influence of the carbonate ion on characteristics of electrochemically synthesized layered (α+β) nickel hydroxide

Nickel hydroxide is widely used as the active material of supercapacitors. The most active are samples of Ni(OH)2 with (α+β) layered structure, synthesized in the slit diaphragm electrolyzer. Influence of carbonate anion on the structure and electrochemical properties of nickel hydroxide samples has been studied by means of sample synthesis in the slit-diaphragm electrolyzer with the use of the diaphragm and cation-exchange membrane as chamber separator. The experiment revealed that when the diaphragm is used, there is a filtration flow from the anodic chamber (alkali with carbonate) into the cathodic chamber. Thus, the samples synthesized with the diaphragm are formed in the presence of carbonates, while the samples synthesized with the cation-exchange membrane – in the absence of carbonates. Crystal structure of the samples was studied by means of X-ray diffraction analysis, electrochemical characteristics – by means of cyclic voltammetry and galvanostatic charge-discharge cycling in the accumulator regime. Comparative analysis of the samples synthesized in the presence or absence of carbonates has been conducted. By means of X-ray diffraction and cyclic voltammetry, the key role of carbonate ions in the formation of monophase layered (α+β) structure has been revealed. The absence of carbonate resulted in lower crystallinity, α-phase content, the formation of the bi-phase system, composed of the mixture of β-form and (α+β)-structure, at high current densities (12 and 15.7 A/dm2). The study of electrochemical characteristics revealed a decrease in specific capacity by 14.7–31.4 % for hydroxide samples formed in the absence of carbonate ions. The highest specific capacity was obtained for the samples synthesized in the SDE at i=10 A/dm2 with the diaphragm (in the presence of carbonates) and with the membrane (in the absence of carbonates), and are 216.8 and 185 mA·h/g respectively. To increase specific capacity, it is recommended to conduct synthesis in the SDE with the use of the diaphragm and introduce an additional quantity of sodium carbonate into the anolyte

Effects of the differential expression of ZO-1 and ZO-2 on podocyte structure and function.

Glomerular podocytes in the kidney originate from columnar epithelial cells possessing tight junctions. During podocyte differentiation, tight junctions are replaced by slit diaphragms, which are formed between foot processes and function as a blood filtration barrier. Although the expression of most tight junction components is suppressed during podocyte differentiation, several components, including ZO-1 and ZO-2, are consistently expressed. We recently showed that podocyte-specific deletion of ZO-1 gene impaired slit diaphragm formation, leading to proteinuria and glomerular sclerosis. Here, we address the relevance of ZO-2, whose sequence is highly similar to ZO-1, in the maintenance of the structure and function of podocytes. In glomerular development, the spatiotemporal expression of ZO-2 was similar to that of ZO-1 until the capillary loop stage. Subsequently, the distribution patterns of ZO-1 and ZO-2 diverged at the maturation stage, when slit diaphragms are formed. This divergence could partly rely on the ability of ZO-2 to interact with the slit diaphragm membrane proteins. Podocyte-specific deletion of the ZO-2 gene did not cause overt defects; however, double knockout of ZO-1 and ZO-2 genes accelerated the defects observed in ZO-1 knockout mice. These results suggest that ZO-2 plays supportive roles in the ZO-1-dependent regulation of podocyte filtration barrier.

Modeling analysis and fabrication of MEMS capacitive differential pressure sensor for altimeter application

This paper proposes the modeling analysis of MEMS highly sensitive Capacitive Differential Pressure Sensor (CDPS) and also the development of a fabrication process for CDPS structures for aircraft altimeter applications. Highly sensitive CDPS structure models using circular and square sandwich polyimide diaphragm membranes, with and without center boss, were adopted, whereas other studies report on silicon diaphragms. CDPS characterization was carried out to analyze the deflection sensitivity, capacitive sensitivity, stress on diaphragm membrane and the effect of temperature on capacitive sensitivity. Simulation results of square diaphragm without center boss show better characteristics than other proposed diaphragm structures. This design yields 145.8 nm/mbar and 0.574 fF/mbar of deflection and capacitive sensitivity, respectively. The maximum stress developed on the diaphragm at maximum working pressure is less than the yield stress of polyimide material by a factor of 1.77 and capacitive sensitivity deviates at ±0.00195%/°C. From the modeling analysis, square diaphragm CDPS structure yields better characteristics and hence the fabrication process for CDPS has been developed, and its fabrication process flow verified using Intellisuit virtual fab tool.

Development of electrospun composite as substitutive diaphragm membrane

The diaphragm is the most important muscle for respiration with a bi-domed structure, which is separating thoracic cavity from abdominal cavity. Partial formation of diaphragm, with unknown reason during fetal development caused a birth defect called congenital diaphragmatic hernia (CDH). It allows the abdomen contents to go up into the chest cavity resulting in pulmonary hypoplasia, which is the major cause of the mortality. There are several types of membrane, which can be used as prostheses to close the existing hole. In this project, we study the tensile properties of electrospun PA-6 nanowebs and electrospun PA-6/B composite as substitution membrane by a comparison with the tensile properties of tendon part of pig’s diaphragm.

Concentration and extraction chip of fetal nucleated red blood Cells (NRBCs) by micro gap with diaphragm for fetal DNA diagnosis from maternal blood

To realized cell-based noninvasive diagnosis of fetal DNA from maternal blood, a extraction of nucleated red blood cells (NRBCs) was performed on the micro gap chip. This chip utilized the phenomena that NRBCs were harder to pass through the micro gap due to their size and hardness of nuclei than other blood cells. By the micro gap, NRBC is trapped selectively from the blood. By employing of the air-driven diaphragm membrane at the micro gap, the gap can be expanded after trapping of NRBCs, and the trapped NRBCs were successfully recovered to outside of the chip. By this procedure, we can extract the NRBCs from the blood. The recovered yield of NRBCs and removal rate of white blood cell and red blood cell were investigated as a function of micro gap size and flow rate. In the optimal condition, more than 90% of recovery yield and more that 90% of removal rate for RBCs and WBCs were achieved. The micro gap chip is considered to be effective to extract NRBCs from blood and expected to shorten the total diagnosis time.

Nanostructural Analysis of CMOS-MEMS-Based Digital Microphone for Performance Optimization

In this paper, systematic analysis on the digital microphone is performed using energy dispersive X-ray spectroscopy (EDS) and transmission Kikuchi diffraction (TKD) in the scanning electron microscopy (SEM). Digital microphone is an integrated chip composed of complementary metal-oxide semiconductor (CMOS) and micro-electro-mechanical systems (MEMS). Using EDS, quantitative chemical composition and elemental maps on the integrated CMOS-MEMS-based microchip were obtained. Microanalytical X-Ray technique along with TKD was applied to reveal the nanostructure of the MEMS region, i.e., diaphragm membrane and then the CMOS region, i.e., tungsten through-silicon via. Device performance and lifetime were correlated with chemical diffusions, metal interface boundaries, grain structures, and phases existing at CMOS and MEMS junctions. Our results demonstrated that SEM-based TKD with EDS is a powerful microstructural characterization tool and performs vital role in failure analysis for device optimization.

3-D printed composite microfluidic pump for wearable biomedical applications

An integrated wearable 3-D printable microfluidic pump was developed, which uses a novel actuation process. Fused deposition manufacture 3-D printing was used as a means to accurately produce this device. This resulted in the fabrication of high precision integrated parts made from poly-lactic-acid bioplastic. By integrating an electro-magnetically actuated closed diffuser nozzle pump configuration a micro-fabricated microfluidic pump has been produced. Biofluids have been driven through the device by actuating a composite polydimethylsiloxane diaphragm actuated polymeric microstructure diaphragm membrane using electromagnetic force. This composite diaphragm was made by suspending 10μm iron particles in the polydimethylsiloxane at concentrations of 30%, 40% and 50%. It is shown that this device acts as an effective electromagnetic force actuated a pump. It is successfully demonstrated that a square wave electromagnetic signal is effective for generating a 2.2μL/min flow rate of biofluid. The integration of 3D printed devices to form a micropump is proven through practical testing which demonstrate a controllable flow rate was generated.

Application of Microsecond Voltage Pulses for Water Disinfection by Diaphragm Electric Discharge

The paper presents the dependence of copper and silver ions formation on the duration of voltage pulses of diaphragm electric discharge and on the pH of treated liquid medium. Knowing it allows one to create an automatic control system to control bactericidal agent's parameters obtained in diaphragm electric discharge reactor. The current-voltage characteristic of the reactor with a horizontal to the diaphragm membrane water flow powered from the author's custom pulse voltage source is also presented. The results of studies of the power consumption of diaphragm electric discharge depending on temperature of the treated liquid medium are given.

Electrical discharges with liquid electrodes used in water decontamination

The results of experimental investigation of the DC electrical discharge with moving air bubbles in the electrolyte, as well as of high frequency electrical discharge with a diaphragm membrane, within a wide parameter range are presented. We investigated active component formation and enhancement of the wastewater decontamination by means of production of a disinfecting agent with a maximal content of the electrical discharge products (copper and silver ions and hydrogen peroxide).

LMX1B is Essential for the Maintenance of Differentiated Podocytes in Adult Kidneys

Mutations of the LMX1B gene cause nail-patella syndrome, a rare autosomal-dominant disorder affecting the development of the limbs, eyes, brain, and kidneys. The characterization of conventional Lmx1b knockout mice has shown that LMX1B regulates the development of podocyte foot processes and slit diaphragms, but studies using podocyte-specific Lmx1b knockout mice have yielded conflicting results regarding the importance of LMX1B for maintaining podocyte structures. In order to address this question, we generated inducible podocyte-specific Lmx1b knockout mice. One week of Lmx1b inactivation in adult mice resulted in proteinuria with only minimal foot process effacement. Notably, expression levels of slit diaphragm and basement membrane proteins remained stable at this time point, and basement membrane charge properties also did not change, suggesting that alternative mechanisms mediate the development of proteinuria in these mice. Cell biological and biophysical experiments with primary podocytes isolated after 1 week of Lmx1b inactivation indicated dysregulation of actin cytoskeleton organization, and time-resolved DNA microarray analysis identified the genes encoding actin cytoskeleton-associated proteins, including Abra and Arl4c, as putative LMX1B targets. Chromatin immunoprecipitation experiments in conditionally immortalized human podocytes and gel shift assays showed that LMX1B recognizes AT-rich binding sites (FLAT elements) in the promoter regions of ABRA and ARL4C, and knockdown experiments in zebrafish support a model in which LMX1B and ABRA act in a common pathway during pronephros development. Our report establishes the importance of LMX1B in fully differentiated podocytes and argues that LMX1B is essential for the maintenance of an appropriately structured actin cytoskeleton in podocytes.

An Electrochemically Actuated MEMS Device for Individualized Drug Delivery: an In Vitro Study

Individualized disease treatment is a promising branch for future medicine. In this work, we introduce an implantable microelectromechanical system (MEMS) based drug delivery device for programmable drug delivery. An in vitro study on cancer cell treatment has been conducted to demonstrate a proof-of-concept that the engineered device is suitable for individualized disease treatment. This is the first study to demonstrate that MEMS drug delivery devices can influence the outcome of cancer drug treatment through the use of individualized disease treatment regimes, where the strategy for drug dosages is tailored according to different individuals. The presented device is electrochemically actuated through a diaphragm membrane and made of polydimethylsiloxane (PDMS) for biocompatibility using simple and cost-effective microfabrication techniques. Individualized disease treatment was investigated using the in vitro programmed delivery of a chemotherapy drug, doxorubicin, to pancreatic cancer cell cultures. Cultured cell colonies of two pancreatic cancer cell lines (Panc-1 and MiaPaCa-2) were treated with three programmed schedules and monitored for 7 days. The result shows that the colony growth has been successfully inhibited for both cell lines among all the three treatment schedules. Also, the different observations between the two cell lines under different schedules reveal that MiaPaCa-2 cells are more sensitive to the drug applied. These results demonstrate that further development on the device will provide a promising novel platform for individualized disease treatment in future medicine as well as for automatic in vitro assays in drug development industry.

REMOVED: Chemo–mechanical Energy Conversion Device with Enzyme Diaphragm Membrane for Kinetic Biosensors and Drug Release System

REMOVED: Chemo–mechanical Energy Conversion Device with Enzyme Diaphragm Membrane for Kinetic Biosensors and Drug Release System

Simulation Analysis of MEMS Based Capacitive Differential Pressure Sensor for Aircraft Application

In this paper, simulation solution for Microelectromechanical systems (MEMS) based capacitive differential pressure sensor for aircraft altimeter is proposed. The principle of proposed MEMS capacitive differential pressure sensor design was explained. Analysis for the measurement of center deflection and capacitive sensitivity square diaphragm membrane was done. Simulation on deflection and capacitive sensitivity was carried out for the range of pressure from 100mbar to1100mbar. Gold, diaphragm membrane was used in this analysis. Analysis result shows, linear variation on center deflection and capacitance variation which is more suitable for this application.

Micromechanical Magnetic Sensor Based on Cylindrical Ferromagnets

In order to solve the problems of cantilever-based magnetic sensors and develop the simple and low-cost magnetic field sensors, novel sensors based on a cylindrical ferromagnet attached to a silicon diaphragm and piezoresistive membrane are proposed. The interaction between the magnetic field and the ferromagnet generates a deflection of the diaphragm, which changes the piezoresistance and unbalances a Wheatstone bridge. The sensitivity of the sensors is proportional to the permeability, supply voltage, and aspect ratio of the ferromagnet. These low-cost, low-power sensors are easily integrated with electronic circuits.

The Study of a MEMS Magnetic Field Sensor Based on “Cross-Shape” Ferromagnetic Film

Novel magnetic field sensors are based on a “cross-shape” ferromagnetic film (FMF) attached to a silicon diaphragm and piezoresistive membrane. The interaction between the magnetic field and the (FMF) generates a deflection of the diaphragm, which changes the piezoresistance and unbalances a Wheatstone bridge. The effect of FMF and silicon diaphragm thickness on the sensor performance is studied by the finite element simulation. The performance of sensor can be improved by optimizing the size of “cross-shape” FMF. These low-cost, low-power sensors are easily integrated with electronic circuits.

초고온용 다결정 3C-SiC 마이크로 압력센서의 제작

High temperature micro pressure sensors were fabricated by using polycrystalline 3C-SiC piezoresistors grown on oxidized SOI substrates by APCVD. These have been made by bulk micromachining under <TEX>$1{\times}1mm^2$</TEX> diaphragm and Si membrane thickness of <TEX>$20{\mu}m$</TEX>. The pressure sensitivity of implemented pressure sensors was 0.1 mV/<TEX>$V{\cdot}bar$</TEX>. The nonlinearity and the hysteresis of sensors were <TEX>${\pm}0.44%{\cdot}FS$</TEX> and <TEX>$0.61%{\cdot}FS$</TEX>. In the temperature range of <TEX>$25^{\circ}C{\sim}400^{\circ}C$</TEX> with 5 bar FS, TCS (temperature coefficient of sensitivity), TCR (temperature coefficient of resistance), and TCGF (temperature coefficient of gauge factor) of the sensor were -1867 ppm/<TEX>$^{\circ}C$</TEX>, -792 ppm/<TEX>$^{\circ}C$</TEX>, and -1042 ppm/<TEX>$^{\circ}C$</TEX>, respectively.