Double Chamber Research Articles

Kiosk 2Q-FA-08 - A Case of Double Chamber Right Ventricle Masquerading as Pulmonic Stenosis on Echocardiogram

Kiosk 2Q-FA-08 - A Case of Double Chamber Right Ventricle Masquerading as Pulmonic Stenosis on Echocardiogram

Relationship between organic removal and power production in a dual-chamber microbial fuel cell with intermittent mode

Unoptimised simultaneous performance in microbial fuel cell (MFC) is still a big concern due to a lack of information on the correlation between organic removal and power production. Its correlation becomes more substantial owing to the main factors which affect a concurrent condition. To contribute new insight, this study aimed to analyze the relationship between the main factors for determining the optimal condition of MFC performance. Dual-chamber MFC (DCMFC) was designed by modifying the anode chamber into two compartments, namely double anode chamber DCMFC (DAC-DCMFC), operated within 8 days running with intermittent mode. The differences of organic loading rate (OLR), 0.4; 1.0; 2.5 kg.m−3.d−1 represented low to high organic loadings and electrode material-based reactor types, were used to assign the optimal concomitant performance in DCMFC. A closed circuit voltage (CCV) wiring system plugged onto the data logger within running time was employed to evaluate the synchronous achievement. This study result was medium OLR 1.0 kg.m−3.d−1, and GNPs anode-PTFE cathode attained optimally in the performance. In addition, higher OLR does not indicate higher organic removal correlating linearly with power production. This finding contributes to the limitation of organic loading that biological role capabilities can use.

Performance analysis of the damper with built-in magnetorheological valve

Commercial vehicles are usually equipped with suspension seats to improve ride comfort. As a semi-active intelligent device, magnetorheological damper can effectively improve seat comfort when applied to seat suspension. Firstly, a novel damper with built-in magnetorheological valve (MRVD) based on the squeeze mode of magnetorheological fluid (MRF) is designed, which integrates the magnetorheological valve (MRV) into the piston. This structure adopts a bidirectional controllable flow channel, double coil, and double squeeze chamber. Secondly, the mathematical model of the MRVD is derived based on the Bingham plastic model of the MRF. Then, the distribution of magnetic flux density in the effective damping gaps is simulated using finite element method. Finally, it is shown from a comparative work between the simulation results from the derived mathematical model and experimental test results of the MRVD that the established mathematical model can predict the field-dependent damping force well. The idea of integrating the MRV into the piston provides a new approach for the application of magnetorheological technology.

Impact of Millet Food on the Nutritional Status of Preschool Children in Coimbatore, tamil Nadu

"Millets have great potential for being utilized as health food by virtue of their nutritional qualities. To study the effect of supplementation of multi-millet mix on the nutritional status of preschool children (age group of 4-6 years; n = 60) Thondamuthur block of Coimbatore district, India, was selected. Millets (kodo millet, little millet, foxtail millet) were soaked at 80°C for 8hours, open steamed for 20°C and shade dried for moisture content of 14 per cent. The hydrothermal treatment of millets was dehulled in double chamber centrifugal dehuller. Which gave increased dehulling efficiency of 5.5% and 7% head rice recovery were recorded. The millets rice was pulversied into flour and the flour used for further development of various value added products. Multi-millet health mix was formulated using flours of wheat, kodo millet, little millet, foxtail millet, and finger millet with other ingredients (pulses & nuts) and their nutritional composition was analysed using standard procedures. The formulated mix contains 65.45 g carbohydrate, 11.46 g protein, 4.94 g fat, 4.94 g fibre, 4.07 g iron, 112 mg calcium, 268.52 mg phosphorus and 349 calorie of energy per 100g. The selected preschool children were divided into two groups. Group I served as the control group (n = 30) and group II as experimental group (n = 30) was fed with multi-millet health mix (25 g) in the form of porridge (75 ml) for 6 months period. Anthropometric and haemoglobin levels were assessed before and after supplementation. In preschool children of experimental group, an average increase in mean height (2.82 cm) and weight (2.64 kg) were observed. Given the positive effect of multi-millet health mix on improving the nutritional status of preschool children, it can be introduced as part of State nutrition programs and health food regime of health organizations and practitioners."

When valve needs electrical wires - estimating pacemaker implantation after TAVR

Abstract Introduction Widespread availability and expanded indication of transcatheter aortic valve replacement (TAVR) modified paradigm of aortic stenosis. Despite elevated success rate, there are procedure related complications that need to be considered. One of the most frequent is conduction defects requiring permanent pacemaker (PPM) implantation resulting in prolonged hospital length of stay and hospitalization cost. Several risk factors for PPM implantation after TAVI have been described, and, recently, the Emory Risk Score (ERS) was developed as a predictive tool for need of new PPM implantation post-TAVI in patients who implated a balloon-expandable valve. Purpose Our objective was to evaluate risk factors associated with PPM after TAVR and to validate the ERS in our population after implantation of balloon-expandable but also self-expanding valves. Methods Retrospective, observational and single center study involving patients submitted to TAVR between 2018 and 2021. Clinical, ECG data and procedure characteristics were obtained at time of TAVR and during follow-up. The predictive discrimination of the scoring system for the risk for PPM placement after TAVR was evaluated using ROC curve analysis in SPSS Statistics. To estimate additional predictors of pacemaker implantation we used Cox proportional hazards regression models. Results From January 2018 to December 2021, 416 patients were referred to our centre for TAVR. The mean age was 82,5 ± 6,1 years, 55% female. Most frequently implanted valves were Evolut Pro and Sapien 3 ultra in 39,4% and 26,6% of pts, respectively. During follow-up 110pts (26%) needed device implantation (94 % double chamber pacemaker; 6% CRT-P or CRT-D), most frequently due to AV block. On univariate analysis, QRS width was the only factor that showed a significant correlation with pacemaker implantation (HR 1,018, 95% CI 1,007-1028; p=0.027). We found no other clinical or procedural characteristics to be predictive of PM implantation. ERS is composed of 4 variables – history of syncope, right complete branch block, QRS width > 140mseg and valve oversizing > 16% - and revealed a good sensitivity and specificity in estimating device implantation. We applied this score to our population and ROC curve analysis showed a significant prediction capacity (AUC 0,761 95% CI 0,699-0,822, p=0,031). This analysis was also performed analysing separately both subgroups of self-expandable valves (Medtronic Evolut and Evolut R) and balloon expandable valves (Edwards Sapiens). ROC curve analysis in both showed a good correlation with events – figure 1. Conclusion PM implantation is one of the most common complications following TAVR. In our population, the use of ERS displayed a very positive accuracy in predicting device implantation. Routine use of such tool can select patients at significant higher risk and thus best define patient allocation and resource utilization to reduce number of hospitalization days.

Numerical simulations on the performance of transpiration cooling implemented with perforated flat plates

Transpiration cooling is an effective method of protecting high-temperature components. However, this technology is currently not applicable to turbine blades because conventional sintered porous materials cannot precisely control the geometric parameters of the cooling channels and coolant outlets. In this study, numerical simulations using the conjugate heat transfer method were conducted to study the effects of hole diameter, injection ratio, and mainstream Reynolds number on the cooling performance of perforated flat plates. A novel optimisation method for the overall transpiration cooling efficiency that reduces coolant consumption through a nonuniform coolant allocation strategy was proposed. The effects of different pore diameters (0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm) on transpiration cooling were investigated numerically. The results revealed that the hole diameter had a marginal effect on the average cooling efficiency of transpiration cooling under the same coolant-injection ratio. With dense heat transfer occurring within the solid matrix, the influence of variations in the pore size was diminished. However, the nonuniformity of the cooling efficiency on the hot wall surface increased with increasing pore size. A double coolant chamber non-uniform injection was adopted for the 0.3 mm perforated plate. The results indicated that there is an optimum coolant allocation ratio for achieving the highest average cooling efficiency with a certain coolant.

Comparative Studies of Thermal Conductivity Determination in Synthetic Wood with Recyclable Waste Content Using an Experimental Design Approach

Waste has become an everyday subject, especially its efficient recycling due to the increasing decline in the planet’s primary resources. Therefore, their recovery is intended to be total and with minimal energy consumption. Biomass waste is fully recoverable in raw or processed states and in combination with other compatible waste types (including wastewater from construction, polymers, and sunflower seeds). It represents the basic elements for obtaining synthetic wood to replace natural wood, which is very expensive and difficult to obtain (lasts for several years). This paper proposes three methods to determine the thermal conductivity of these new materials (synthetic wood) to guarantee and optimise their thermal characteristics. The determination of thermal characteristics in insulating materials is usually performed experimentally in a double climate chamber or more simply using a special instrument of the ISOMET type, but under these conditions, the sample must meet certain conditions imposed by the manufacturer to be tested. Thus, two experimental investigation methods are used to which a numerical method is added, which consists of modelling by the finite element method with an adequate programme of heat transfer through these materials. Four samples with variable content of recyclable waste obtained through combinations resulting from six different experimental design plans with two controlled factors were analysed to optimise synthetic wood recipes for the efficiency of their hygro-thermal characteristics. The content of the tested samples varied relative to the quantity and number of recyclable wastes included in the final recipe. Thus, the thermal conductivity obtained was different for each sample but close to that of similar synthetic wood-type materials and natural wood.

Numerical simulation and experiment of double chamber brake based on CFD

The artillery firing process will instantly produce high-temperature and high-pressure gunpowder gas, this process will produce shock waves. The gunpowder gas has a limited effect on the projectile during the firing and ballistic after-effects period, however, it has a very obvious effect on the stability of the gun body, and the reduction of the stability of the gun body directly affects the firing accuracy and the safety of the firing personnel. Based on the method of Computational Fluid Dynamics (CFD), numerical simulation is carried out, and the structure and flow parameters of the muzzle flow field are obtained by using three-dimensional Euler's control equation, gas equation of state, and k-epsilon model, as well as dynamic mesh technology. By comparing the flow parameters of the brake before and after optimization, and analyzing the results obtained from the 8-round firing experiments, the efficiency of the optimized brake is increased by 8.2%, and the deviation between the experimental data and the simulation results is only 10.5%, which not only verifies the accuracy of the numerical simulation calculations but also verifies the optimized brake's good retracting effect. The results of the study can provide a reference for the optimization and design of the double-chamber brake.

BIOELECTRICITY OF COCOA POD WASTE AS A SUBSTRATE IN A DOUBLE CHAMBER MICROBIAL FUEL CELL

Currently, the utilization of cocoa pod has not been maximized, resulting in waste and foul odors that disturb the environment. However, cocoa pod contain a relatively high amount of cellulose compounds that serve as an energy source or nutrition for bacteria to carry out metabolic activities, thus holding the potential to be used as a substrate in microbial fuel cells (MFC). Based on this, the aim of this research is to investigate the bioelectricity generated by a MFC using cocoa pod husk as a substrate, including voltage, current, and power density, in order to determine the potential of cocoa pod husk waste as an electrical energy source. In this study, a double chamber MFC consists of an anode chamber with copper electrodes and a cathode chamber with zinc electrodes, separated by a salt bridge. The bacteria used were Saccharomyces cerevisiae, and the substrate was made from cocoa pod husk waste. Bioelectricity testing involved measuring the voltage, current, and power density produced by the MFC over several minutes. The measurement results for maximum voltage, maximum current generated, and maximum electrical power (at 6 days) from the reactor were as follows: 36.0 mV, 0.19 mA, and 456 mW/m2, respectively.

An unusual case of late spontaneous reattachment of Descemet membrane detachment after deep anterior lamellar keratoplasty: A case report

Deep anterior lamellar keratoplasty (DALK) is a feasible option in children with advanced keratoconus with or without stromal scarring. Descemet membrane detachment (DMD) and formation of double anterior chamber is one of the rare but serious complication of DALK surgery. Various treatment methods like descemetopexy with air, perfluoropropane gas (C3F8), and SF6 (sulfur hexafluoride gas) can be tried. We report a case of spontaneous reattachment of DMD in a pediatric male patient with Descemet membrane microperforation during DALK.

Sensitivity analysis and noise reduction optimization design of the insert-pipe double expansion chamber muffler

The insert-pipe double expansion chamber muffler has less passbands and higher sound attenuation in the plane wave range, which is widely used to reduce noise of industrial equipment. But there are many parameters that affect the transmission loss of the insert-pipe double expansion chamber muffler, and the sensitivity of each factor is not clear. Identifying the most influential factor among numerous parameters is an important challenge. It is necessary to investigate the sensitivity of all parameters and study parameter optimization algorithms. Based on the method of transfer matrix analysis, this paper studies the insert-pipe double expansion chamber muffler and its sound elimination mechanism. The global sensitivity analysis of the transmission loss of insert-pipe double expansion chamber muffler was conducted using Sobol's method, and the influence of each parameter sensitivity was examined. According to the noise characteristics of an air conditioner compressor, the external penalty function method (EPFM) algorithm is used to optimize the insert-pipe double expansion chamber muffler, and the maximum transmission loss is obtained in a specific frequency band. According to the optimized parameters, the muffler is designed, manufactured, and installed in a pipeline system to carry out a noise experiment to verify the effectiveness of the optimization scheme.

Experimental study on the sintering characteristics of biomass ash

The alkaline metal content in biomass is high, which leads to a low initial sintering temperature. Therefore, during the process of direct biomass combustion for power generation, there are serious problems such as ash deposition and slagging on the heating surface, which has become a technical bottleneck for the safe, stable and long-term operation of boilers. In industry, the melting characteristics of ash are commonly used to guide boiler design and operation. However, traditional measurement of ash melting temperature has a large subjective error, and the releasing of alkaline metals during the measurement process results bit higher value, which affects the accuracy of the measured characteristic temperature. Comparingly, the initial sintering temperature is lower than the deformation temperature of the ash. This article provides a device for measuring the sintering temperature of biomass ash by using the pressure drop method. A novel two ash chamber system was invented, in which the alkali element released from the first ash chamber was captured by the downstream second ash chamber to compensate the escaping of alkali element. The initial sintering temperature of the second ash chamber has more accuracy with lower value than that measured by the traditional single sample chamber. XRD was used to analyze the mineral composition and causes of sintering of the ash samples before and after sintering. The results show that the sintering mechanisms of different types of biomass are different. In addition, combined with SEM analysis of rice husk, fruit core, rapeseed straw, and corn straw, the results show that the initial sintering temperature of the ash samples measured by the double chamber measurement method is more accurate than that measured by the single chamber measurement method, further validating the reliability of the two ash column system.

Fabrication of peristaltic electromagnetic micropumps using the SLA 3D printing method from a novel magnetic nano-composite material

Micropumps are one of the main components of microfluidic systems that play an essential role in the development of these systems. They are responsible for the fluid movement inside the microfluidic systems. In this paper, three electromagnetic micropumps with single, double, and triple chambers fabricated using the stereolithography (SLA) 3D printing method from a novel UV-curable magnetic nanocomposite material are presented. The components of this micropump include nozzle-diffuser microchannels, a chamber, a flexible magnetic membrane, and a micro-coil. To determine the characteristics of the proposed micropumps, the effect of the electric current signal and its patterns and magnetic field strength on the temperature changes, magnetic nanoparticle concentration on the membrane displacement, and flow rate of the micropump have been investigated. The micropump membrane with 5 wt% nanoparticles concentration can achieve a displacement of 65 µm for an electric current of 1000 mA in 12 s. The highest fluid flow rate of single, double, and triple chamber micropumps are 78, 316, and 600 nL/s, respectively, at an electric signal with a period of 8 s and a duty cycle of 60%.

Assessment of the effective parameters for the enhancement of light-harvesting power in the photoelectrochemical microbial fuel cell

ABSTRACT Photo-assisted microbial fuel cells (PMFCs) are novel bioelectrochemical systems that employ light to harvest bioelectricity and efficient contaminant reduction. In this study, the impact of different operational conditions on the electricity generation outputs in a photoelectrochemical double chamber configuration Microbial fuel cell using a highly useful photocathode are evaluated and their trends are compared with the photoreduction efficiency trends. As a photocathode, a binder-free photo electrode decorated with dispersed polyaniline nanofiber (PANI)−cadmium sulphide Quantum Dots (QDs) is prepared here to catalyse the chromium (VI) reduction reaction in a cathode chamber with an improvement in power generation performance. Bioelectricity generation is examined in various process conditions like photocathode materials, pH, initial concentration of catholyte, illumination intensity and time of illumination. Results show that, despite the harmful effect of the initial contaminant concentration on the reduction efficiency of the contaminant, this parameter exhibits a superior ability for improving the power generation efficiency in a Photo-MFC. Furthermore, the calculated power density under higher light irradiation intensity has experienced a significant increase, which is due to an increment in the number of photons produced and an increase in their chance of reaching the electrodes surface. On the other hand, additional results indicate that the power generation decreases with the rise of pH and has witnessed the same trend as the photoreduction efficiency.

Pacemaker Infective Endocarditis: Diagnostic and Therapeutic Particularities in 2 Case Reports Including One of the Left Heart

Pacemaker infective endocarditis is a more real diagnostic problem than a therapeutic one. The precise impact is not well known. Its incidence is poorly known, and it is a serious infection with an estimated mortality of around 25%. It is with this in mind that we report 2 clinical cases with a literature review.
 Case 1: An 88-year-old patient with a double chamber pacemaker was admitted for febrile syndrome with a fever at 39.2°. Transthoracic and transesophageal echocardiography (TOE) found an image of vegetation on the aortic valve measuring 9mm, located on the noncoronary cusp, and overflowing on the right coronary cusp. An inflammatory syndrome was found on blood tests. Blood culture, wound swab culture, and bacteriological study of material after removal revealed Staphylococcus Aureus Meti S. The patient was initially put on Vancomycin with a loading dose of 2g / 24h then 1g / 24h, and the pacemaker was extracted.
 Case 2: A 68-year-old with a double chamber pacemaker (PM) was admitted for fever at 39 ° c with suppuration of the PM pocket. Echocardiography identified an image on the tricuspid valve measuring 14x8 mm evoking vegetation given the context. Two blood cultures and swabs isolated a Staphylococcus aureus. The patient was administered Triaxon 2g / day for 4 weeks and gentamycin 180 mg for 15 days. The pacemaker was removed.
 Pacemaker Infective endocarditis is rare, poorly understood, very serious, and potentially fatal, accounting for up to about 7% in some case series. In half of the cases, they affect the endocavitary leads, but also the valves, and in 45% of cases the infection of the pocket. The average age is 65 years. The clinical symptoms are disparate making the diagnosis more difficult, it must be evoked in case of unexplained fever in a patient implanted with a Pacemaker. Bactericidal dual therapy should be administered after blood cultures in case of strong suspicion of infective endocarditis (IE) and adapted after identification of the germ in question. Most authors are adamant about extracting any pacemaker whenever possible.

Biochar based cathode enriched with hydroxyapatite and Cu nanoparticles boosting electromethanogenesis

Electromethanogenesis is an innovative technology addressing the need of storing renewable energy from unprogrammable sources. It allows for the electrochemical production of methane from CO2-rich wastes on microbial cathodes, in a logic of power-to-gas (BEP2G). The challenge of cost-effective and sustainable biocathodes enhancing the microorganism performance and yield of electromethanogenesis is approached in this work. For the first time, porous carbonaceous cathodes were functionalized with Cu nanoparticles and hydroxyapatite (HAP) and successfully experimented for supporting microbial CO2 reduction reaction (CO2RR) to methane. Tests were performed in a double chamber system under CO2 flow at 45 °C. Next Generation Sequencing of 16S RNA indicated that the microbial pool on the cathodes was mostly enriched in Metanobacteriaceae (hydrogenotrophic Archaea) and different fermenting bacteria, depending on the cathode type. High methane production on cathodes made of Cu 20%, HAP 10%, and carbon balance (20Cu/10HAP) was achieved, with a maximum of 866 ± 199 mmol m−2 d−1 (projected cathode area, Coulombic efficiency of 64%), corresponding to values comparable to the maximum in literature, but in shorter timespans (8 vs. 30 days). The documented effect of pH stabilization in the cathodic chamber by HAP was one of the main parameters that concurred to the selectivity of CO2RR towards methane.

Electrical Energy Production with Microbial Fuel Cell (MFC) Technology on Gracilaria verrucosa Substrate

Microbial Fuel Cell (MFC) is a renewable technology based on electrochemistry that has the ability to convert chemical energy into electrical energy through microbial metabolic processes. This study aims to determine the effect of adding an electrolyte solution to the production of electricity generated using the substrate Gracilaria verrucosa and the microbe Saccharomyces cerevisiae. The method used in this study uses a double chamber consisting of anode and cathode chambers connected through a proton exchange membrane (PEM) in the form of Nafion 117. The results showed that the addition of 0.2 M KMnO4 electrolyte solution produced current, voltage and power density respectively. of 0.74 mA; 580 mV and 2187 mW/cm2 higher than the addition of 0.2 M K3Fe(CN)6 electrolyte solution resulted in a current, voltage and power density of 0.69 mA, respectively; 450 mV and 1582.16 mW/cm2. The MFC system using Gracilaria verrucosa as a substrate has the potential to generate electrical energy. Keywords: Microbial Fuel Cell (MFC), Electrical energy, Gracilaria verrucosa, Saccharomyces cerevisiae

Double chamber meso scale vortex combustor for micro scale electric generator based on thermo electric generator

Research on micro/meso combustor-based small-scale power plants is developing rapidly. This rapid development is motivated by a higher energy density than lithium-ion batteries. In addition, energy needs for portable and mobile devices also drive this development. Based on the opportunities and needs of these small-scale power plants, this study focuses on developing a double-chamber mesoscale vortex combustor. This research aims to compare the temperature profile and the electrical energy generated by single and multiple combustion chambers on the meso vortex combustor. The single chamber combustor has 56 × 28 × 10 mm, and the double combustor is 56 × 56 × 10 mm. Both meso vortex combustor has dimension with a 4 mm inlet diameter. In the meso scale vortex combustor, we also installed stainless steel wire mesh to compare the temperature with and without wire mesh. Based on the numerical study results, the flame can be stabilized in the double chamber combustor configuration. The wire mesh installation can enhance the flame stabilization process. Nevertheless, the wire mesh installation reduces the wall temperature because the mixture’s exit velocity is more stable than the combustor without the wire mesh. The result shows that a double chamber meso scale vortex combustor has a higher temperature and electric energy output than a single chamber combustor. The double chamber combustor can generate 9.5 Watt electric power with 12.6% energy conversion efficiency.

Comprehensive study of the level of electrolyte in selected organic wastes by using double chamber microbial fuel cell

Comprehensive study of the level of electrolyte in selected organic wastes by using double chamber microbial fuel cell

Production potential of cow dung for the generation of electric current using microbial fuel cell

Production potential of cow dung for the generation of electricity was investigated using microbial fuel cell (MFC). Cow dung was collected from FUTA farm and Ilesha Garage farm in Akure. Voltage and current was measured per day for 21 days and the electrode used for the set up are carbon-carbon and carbon-aluminium electrode. Proximate, physico-chemical and mineral composition were determined using standard methods. Isolation and identification of microorganisms present in the cow dung were determined before and after generation of voltage and current using microbiological techniques. The microorganisms isolated were Providencia alcalifaciens, P. rettgeri, P. stuartti, Escherichia coli, E. fergusonii, Morganella morganii, Staphylococcus haemolyticus, S. aureus, Micrococcus luteus, Fusarium solani, Saccharomyces cerevisiae and Mucor mucedo. The highest voltage 0.737±0 mV and electric current 1.265±0 mA were generated from FUTA cow dung. The pH ranged between 7.3 to 9.9 and the temperature ranged between 25 ˚C to 33 ˚C during generation of voltage and current. This study has shown that cow dung is a potential substrate for generation of electric current using fabricated double chamber MFC.