Increase In Volumetric Flow Rate Research Articles

Response Time Dynamics of a Membrane-Based Microfluidic Gas Sensor

Practical gas–liquid interfacing is paramount in microfluidic technology, particularly in developing microfluidic gas sensors. We have created an easily replicable membrane-based closed microfluidic platform (MB-MP) to achieve in situ gas–liquid contact for low-resource settings. We have fabricated the MB-MP using readily available materials like double-sided tape or parafilm without conventional soft lithographic techniques. The response characteristics of the MB-MP are studied using CO2 as the model gas and bromothymol blue dye as the sensing material. The dye’s color change, indicative of pH shifts due to CO2 absorption, is captured with a digital microscope and analyzed via the ImageJ software package v1.54g. The response shows saturation and regeneration parts when cycled between CO2 and N2, respectively. Experiments are conducted to investigate the response characteristics and saturation rate under different conditions, including changes in volumetric flow rate, gas stream velocity, and dye solution volume. We observe experimentally that an increase in volumetric flow rate decreases the delay and increases the saturation rate of the response, surpassing the impact of the gas stream’s increased velocity. Furthermore, increasing the dye volume results in an exponential decrease in the saturation rate and an increase in the delay. These insights are essential for optimizing the platform’s response for point-of-use applications.

Evaluation of Heat Decarbonization Strategies and Their Impact on the Irish Gas Network

Decarbonization of the heating sector is essential to meet the ambitious goals of the Paris Climate Agreement for 2050. However, poorly insulated buildings and industrial processes with high and intermittent heating demand will still require traditional boilers that burn fuel to avoid excessive burden on electrical networks. Therefore, it is important to assess the impact of residential, commercial, and industrial heat decarbonization strategies on the distribution and transmission gas networks. Using building energy models in EnergyPlus, the progressive decarbonization of gas-fueled heating was investigated by increasing insulation in buildings and increasing the efficiency of gas boilers. Industrial heat decarbonization was evaluated through a progressive move to lower-carbon fuel sources using MATLAB. The results indicated a maximum decrease of 19.9% in natural gas utilization due to the buildings’ thermal retrofits. This, coupled with a move toward the electrification of heat, will reduce volumes of gas being transported through the distribution gas network. However, the decarbonization of the industrial heat demand with hydrogen could result in up to a 380% increase in volumetric flow rate through the transmission network. A comparison between the decarbonization of domestic heating through gas and electrical heating is also carried out. The results indicated that gas networks can continue to play an essential role in the decarbonized energy systems of the future.

An Investigation into the Volumetric Flow Rate Requirement of Hydrogen Transportation in Existing Natural Gas Pipelines and Its Safety Implications

As an alternative to the construction of new infrastructure, repurposing existing natural gas pipelines for hydrogen transportation has been identified as a low-cost strategy for substituting natural gas with hydrogen in the wake of the energy transition. In line with that, a 342 km, 36″ natural gas pipeline was used in this study to simulate some technical implications of delivering the same amount of energy with different blends of natural gas and hydrogen, and with 100% hydrogen. Preliminary findings from the study confirmed that a three-fold increase in volumetric flow rate would be required of hydrogen to deliver an equivalent amount of energy as natural gas. The effects of flowing hydrogen at this rate in an existing natural gas pipeline on two flow parameters (the compressibility factor and the velocity gradient) which are crucial to the safety of the pipeline were investigated. The compressibility factor behaviour revealed the presence of a wide range of values as the proportions of hydrogen and natural gas in the blends changed, signifying disparate flow behaviours and consequent varying flow challenges. The velocity profiles showed that hydrogen can be transported in natural gas pipelines via blending with natural gas by up to 40% of hydrogen in the blend without exceeding the erosional velocity limits of the pipeline. However, when the proportion of hydrogen reached 60%, the erosional velocity limit was reached at 290 km, so that beyond this distance, the pipeline would be subject to internal erosion. The use of compressor stations was shown to be effective in remedying this challenge. This study provides more insights into the volumetric and safety considerations of adopting existing natural gas pipelines for the transportation of hydrogen and blends of hydrogen and natural gas.

Extraction of chromium (III) from aqueous waste solution in a novel rotor-stator spinning disc reactor

In this work, the removal of chromium (III) from aqueous waste solution by solvent extraction with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (P507) as extractant is investigated in a novel rotor-stator spinning disc reactor. The effect of rotational speed, volumetric flow rate and rotor-stator distance on extraction efficiency and volumetric mass transfer coefficient are studied. Experimental results indicates that the maximum values of extraction efficiency and volumetric mass transfer coefficient are 97.2 % and 0.40 1/s, respectively. The mass transfer performance inside the rotor-stator spinning disc reactor exceeds that of conventional reactors. Moreover, it is found that the extraction efficiency increases with the increase of rotational speed but with the decrease of volumetric flow rate and rotor-stator distance. The Volumetric mass transfer coefficient increases as both the rotational speed and volumetric flow rate increase, but decreases with the increase of rotor-stator distance. Furthermore, an analysis on the relationships between volumetric mass transfer coefficient and various parameters is launched by the grey correlation method. The calculation result shows good coincidence with the experimental data.

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet.

Laser ablation of bone for the purposes of osteotomy is not as well understood as ablation of homogeneous, non-biological materials such as metals and plastics. Ignition times and etch rate can vary during ablation of cortical bone. In this study, we propose the use of two techniques to optimize bone ablation at 1064nm using a coaxial nitrogen jet as an assist gas and topical application of graphite as a highly absorbing chromophore. We show a two order of magnitude reduction in mean time to ignition and variance by using the graphite topical chromophore. We also show that an increase in volumetric flow rate of the assist gas jet does show an initial increase in etch rate, but increased pressure beyond a certain point shows decreased return. This study also demonstrates a 2 nd order relationship between exposure time, volumetric flow rate of nitrogen, and etch rate of cortical bone. The results of this study can be used to optimize the performance of laser ablation systems for osteotomy. This is a companion study to an earlier one carried out by Wong et al. [Biomedical Opt. Express6, 1 (2015)].

Diazinon removal from aqueous media by mesoporous MIL-101(Cr) in a continuous fixed-bed system

Thanks to their remarkable features (i.e. extremely high surface areas and porous structures with tunable pore sizes), MOFs are promising materials for adsorption of different traceable pollutants from wastewaters. In this study, MIL-101(Cr), is synthesized and examined as a capable adsorbent for removal of diazinon from aqueous media in a continuous fixed-bed system. The properties of the MIL-101(Cr) are determined applying SEM, XRD, FTIR, TGA, HRTEM and BET characterization techniques. Accordingly, mesoporous octahedral structure, 96% crystallinity, up to 550 °C thermal stability and about 2600 m2/g BET surface area are obtained. The impacts of the operative factors (the initial pH, the initial diazinon concentration, the volumetric flow rate and the bed depth) on diazinon removal efficiency are further examined. Also, EDS and FTIR tests are employed to explore the diazinon adsorption on the adsorbent surface. It is obtained that neutral pH is the best choice to achieve the maximum removal efficiency (92.5%). The highest bed height (1 cm) contributes to the longest breakthrough time (13 min) while increase in volumetric flow rate and initial diazinon concentration lead to decrease of exhaustion time. Utilizing the experimental data, Langmuir isotherm is the best fitted adsorption isotherm model. Also, the Thomas model predicts the system’s behavior better than Adams–Bohart one. It is the first time that MIL-101(Cr) is applied for adsorption of diazinon from aqueous solutions. As a consequence, it will undoubtedly have noteworthy impacts on agricultural wastewater treatment and can be considered for advanced research as an appropriate agent regarding practical remediation processes.

CFD analysis of roof tile coverings

In hot climates tiled pitched roofs significantly reduce the heat transfer across the roof structure, due to the ventilated air layer between tiles and roofing underlay formed by the arrangement of battens and counter-battens supporting the tiles. This so-called Above Sheathing Ventilation (ASV) depends on the air entering and leaving at the eaves, ridge and the gaps between the tiles. With a view towards higher energy savings in space cooling, the natural and forced convection occurring in ASV could be enhanced by increasing the roof air permeability by means of novel tile shapes, as here analysed in two stages.The first stage of designing the new tile shapes was to measure the air permeability for a type of existing tile (Marseillaise style) using an experimental test rig, by monitoring the volumetric flow rate through the tiles over a range of pressure differences across the tiles. Then, a three-dimensional CFD model was implemented to replicate the full test rig geometry, and this was calibrated against the experimental data. In the next stage, the calibration was used to support the design of novel Marseillaise tile shapes, and to compare their performance against existing tiles. Finally, in order to analyse the variation in air flow under typical wind conditions for a pitched roof, a parametric study was undertaken, consisting of 72 scenarios varying wind speed, direction and angle of incidence.An increase in volumetric flow rate through the tiles was found to be related not only to an increase in the open area between tiles, but also to the design of the tile locks. By redesigning the geometry of these locks, whilst still giving consideration to their primary purpose of preventing the ingress of driving rain, it was possible to yield an improvement in air permeability of up to 100% in comparison with the original designs. Additionally, these novel designs were shown to increase the air flow rate as the wind angle moved from being directly up the roof slope around to the side, in contrast to the decrease seen with existing tile shapes.

Contraction of radiator length in heavy vehicles using cerium oxide nanofluid by enhancing heat transfer performance

In this present investigation, heat transfer performance of CeO2-ethylene glycol as coolants in heat pipes are analyzed. Various concentrations of 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0 vol.% with different volumetric flow 1.0, 2.0, 3.0, 3.5, and 4.0 lpm at a temperature of 40°C, are investigated experimentally and the results are numerically analyzed by means of cross tube heat exchanger and horizontal flow with twist plate insert. The results are scrutinized to evaluate the best concentration which will reduce the size of the existing radiator length. The results demonstrated that, for 0.75 vol.% combination of CeO2-ethylene glycol resulted in increase of heat transfer coefficient compared to the combination of water-ethylene glycol. Increase in volumetric flow rate of the coolant increase the heat transfer coefficient results in the contraction of radiator length. Replacing the original coolant with the proposed combination, it is estimated that the size of the radiator, inventory of the fluid, and pumping power is reduced, thus, making this nanofluid an energy efficient fluid for the engine cooling system.

Mathematical modeling of micropolar fluid flow through an overlapping arterial stenosis

In this study a mathematical model for two-dimensional pulsatile blood flow through overlapping constricted tapered vessels is presented. In order to establish resemblance to the in vivo conditions, an improved shape of the time-variant overlapping stenosis in the elastic tapered artery subject to pulsatile pressure gradient is considered. Because it contains a suspension of all erythrocytes, the flowing blood is represented by micropolar fluid. By applying a suitable coordinate transformation, tapered cosine-shaped artery turned into non-tapered rectangular and a rigid artery. The governing nonlinear partial differential equations under the imposed realistic boundary conditions are solved using the finite difference method. The effects of vessel tapering on flow characteristics considering their dependencies with time are investigated. The results show that by increasing the taper angle the axial velocity and volumetric flow rate increase and the microrotational velocity and resistive impedance reduce. It has been shown that the results are in agreement with similar data from the literature.

Numerical study of microchannel heat sink performance using nanofluids

This study presents the numerical simulation of three-dimensional incompressible steady and laminar and turbulent fluid flow of a trapezoidal micro-channel heat sink (MCHS) using CuO/water nanofluid as a cooling fluid. Navier–Stokes equations with conjugate energy equation are discretized by the finite-volume method. CFD predictions of laminar and turbulent forced convection of CuO/water nanofluids by single-phase and two-phase models (mixture model) are compared. The parameters studied include the particle volume fraction (ϕ=0.204%, 0.256%, 0.294% and 0.4%), and the volumetric flow rate (V˙=10mL/min, 15mL/min and 20mL/min). Comparisons of the thermal resistance predicted by the single-phase and two-phase models with corresponding experimental results show that the two-phase model is more accurate than the single-phase model. In the laminar flow, the thermal resistance of nanofluids is smaller than that of the water, which decreases as the particle volume fraction and the volumetric flow rate increase. In addition, the pressure drop of both nanofluid-cooled MCHS and pure water-cooled MCHS is discussed. For the laminar flow case, the pressure drop increases slightly for nanofluid-cooled MCHS.

Sulfated membrane adsorbers for economic pseudo‐affinity capture of influenza virus particles

Strategies to control outbreaks of influenza, a contagious respiratory tract disease, are focused mainly on prophylactic vaccinations in conjunction with antiviral medications. Currently, several mammalian cell culture-based influenza vaccine production processes are being established, such as the technologies introduced by Novartis Behring (Optaflu) or Baxter International Inc. (Celvapan). Downstream processing of influenza virus vaccines from cell culture supernatant can be performed by adsorbing virions onto sulfated column chromatography beads, such as Cellufine sulfate. This study focused on the development of a sulfated cellulose membrane (SCM) chromatography unit operation to capture cell culture-derived influenza viruses. The advantages of the novel method were demonstrated for the Madin Darby canine kidney (MDCK) cell-derived influenza virus A/Puerto Rico/8/34 (H1N1). Furthermore, the SCM-adsorbers were compared directly to column-based Cellufine sulfate and commercially available cation-exchange membrane adsorbers. Sulfated cellulose membrane adsorbers showed high viral product recoveries. In addition, the SCM-capture step resulted in a higher reduction of dsDNA compared to the tested cation-exchange membrane adsorbers. The productivity of the SCM-based unit operation could be significantly improved by a 30-fold increase in volumetric flow rate during adsorption compared to the bead-based capture method. The higher flow rate even further reduced the level of contaminating dsDNA by about twofold. The reproducibility and general applicability of the developed unit operation were demonstrated for two further MDCK cell-derived influenza virus strains: A/Wisconsin/67/2005 (H3N2) and B/Malaysia/2506/2004. Overall, SCM-adsorbers represent a powerful and economically favorable alternative for influenza virus capture over conventional methods using Cellufine sulfate.

Development and application of a novel swirl cyclone scrubber—(1) Experimental

Conventional cyclones have a lower collection efficiency for smaller particles and conventional wet scrubbers have significant clogging and fouling problems by salt formation at the tip, the inside and outside of the nozzles, the tubes and the walls of scrubbers. Also, many companies and manufacturing sites have been in trouble for collecting their adhesive particulates. The novel swirl scrubber that we have developed consists mainly of a cyclone and a swirl scrubber with an impact cone and plates. This study reports the collection efficiency of particulates and the application of the novel swirl scrubber. The particle collection efficiency as a function of particle size was investigated with changes of plate angles, nozzle size and pressure, and volumetric flow rate of scrubbing medium. The particle collection efficiency increased with a decrease in plate angle, an increase in pressure of scrubbing medium at the nozzle tip, and an increase in volumetric flow rate of the scrubbing medium. The collection efficiency of PM 10 by scrubbing effect was much higher than that by cyclonic effect. In particular, the total increase in particle collection efficiency by scrubbing effect was significant (around 2.5 μm) in particle aerodynamic diameter. The developed novel swirl scrubber can be used for significantly increasing the collection efficiency of TSP, PM 10, and PM 2.5, in particular, which have adhesive characteristics. The costs for installation, operation and maintenance of the scrubber system are much cheaper than those of cyclones and scrubbers or other particulate collecting devices.

1651 線一非平行平板型直流電気流体ガスポンプの特性 : 第一報,線電極絶縁カバーの影響(G05-8 流体機械(1),G05 流体工学)

The experiments were conducted to study the effects of positive polarity applied voltage on time averaged discharge current, gas velocity, volumetric flow rate and pressure rise for a wire-non-parallel plate type EHD gas pump with a conversion cylindrical flow channel at atmospheric pressure and room temperature, where air was as the working fluid. Furthermore, insulation plastic tubes covered partially around corona wire were tried to use for EHD gas pump in order to increase velocity and volumetric flow rate. Experimental results show that; (1) Depending on applied voltage, corona wire and grounded electrode positions, slope of grounded electrode and corona wire insulation cover, the maximum gas velocity 1.7m/s and volumetric flow rate 2.0l/min were observed; (2) The velocity and volumetric flow rate increase with increasing applied dc voltage and have the peak values at any applied voltage; (3) The effects of the corona wire positions relative to the grounded plate electrodes on the net direction of EHD induced flow are also experimentally investigated.

A high current density DC magnetohydrodynamic (MHD) micropump

This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-microm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined frit-like structure that connects the pumping channel to side reservoirs, where platinum electrodes are located. Current densities up to 4000 A m(-2) could be obtained without noticeable Joule heating in the system. The pump performance was studied as a function of current density and magnetic field intensity, as well as buffer ionic strength and pH. Bead velocities of up to 1 mm s(-1) (0.5 microL min(-1)) were observed in buffered solutions using a 0.4 T NdFeB permanent magnet, at an applied current density of 4000 A m(-2). This pump is intended for transport of electrolyte solutions having a relatively high ionic strength (0.5-1 M) in a DC magnetic field environment. The application of this pump for the study of biological samples in a miniaturized total analysis system (microTAS) with integrated NMR detection is foreseen. In the 7 T NMR environment, a minimum 16-fold increase in volumetric flow rate for a given applied current density is expected.

Modeling of gas-liquid reactions in ladle metallurgy: Part I. Physical modeling

A physical model of a ladle degassing operation was developed to simulate the reactions at rising bubbles and at the free surface. Carbon dioxide desorption from a sodium hydroxide solution was used to simulate the liquid-phase diffusion-controlled decarburization of liquid steel. It was found that under reduced pressure, the reactions were faster than attributable to solely the increase in volumetric flow rate. It was possible to separate the reactions with the bubbles from the free surface reactions; 20 to 40 pct of the reactions occurred at the free surface, depending on injection conditions. The free surface desorption rate depended on the gas flow rate and the number of injectors. The mass transfer coefficients to the bubbles were in reasonable agreement with previous work. Plume bending was observed when small bubbles were influenced by the bulk liquid flow patterns.

Basic nebulizer function.

The main function of a jet nebulizer is to aerosolize the contained liquid. The primary generation point is the orifice where the compressed air expands and increases in velocity. At this point the expanding air induces an underpressure and liquid is sucked up to the air orifice where it meets the rapidly expanding air. Droplets from the liquid surface are carried away with the airstream towards the baffle system. After cut-off by impaction on the baffle surface, secondary generation occurs on the baffle as droplets are produced due to high air velocity. Several different designs of nebulizer are available. The differences cause variation in the output characteristics; for example, in the liquid output and droplet size distribution. There is also disparity between individual nebulizers of the same brand. This is due to manufacturing errors. Repeated use of a single nebulizer over time causes ageing. This, in turn, causes the critical points of droplet generation to change. The most significant changes are the small increases in the diameter of the air orifice. This may be due to mechanical wear from the compressed air source or to extensive cleaning procedures. The effect of the increasing diameter, as seen by the user, is decreased driving pressure at a constant rate of air flow. There is also an effect on the output characteristic of the nebulizer. With decreasing driving pressure the air velocity decreases. This in turn, increases the droplet size generated at the air orifice.(ABSTRACT TRUNCATED AT 250 WORDS)