scholarly journals Darcy–Boussinesq Model of Cilia-Assisted Transport of a Non-Newtonian Magneto-Biofluid with Chemical Reactions

2020 ◽  
Vol 10 (3) ◽  
pp. 1137 ◽  
Author(s):  
Ali Ahmad Farooq ◽  
Zahir Shah ◽  
Poom Kumam ◽  
Ebraheem O. Alzahrani ◽  
Meshal Shutaywi ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Vertical Channel ◽  
Boussinesq Model ◽  
Factors Affecting ◽  
Highly Nonlinear ◽  
The Difference ◽  
Geometrical Factors ◽  
Mixed Convective Flow

The model developed in this study presents a mathematical approach to the physiological transport of seminal liquid due to ciliary movements, which are attached with the lumen of the ductile efferent in the male reproductive system. The rheological properties of the seminal liquids were described using the Jeffrey liquid model. The problem described an electromagnetic mixed convective flow of a Jeffrey liquid through a vertical channel with heat and mass transfers. The effects of chemical reactions and the external heat generation were included in the formulation. The flow took place through an active porous medium (due to thick cilia mat and other deposits) and was influenced by the Lorentz magnetic force. Four basic conservation laws of mass, momentum, energy, and concentration were utilized in the mathematical modeling. These are highly nonlinear equations, which were simplified due to a physiologically valid approach known as LAT (lubrication approximation theory). Analytical solutions for temperature, concentration, and velocity profiles were evaluated. The expressions describing the pressure–volume flow rate relationships were also obtained. Analysis of various physical and geometrical factors affecting the pressure–volume (pumping) characteristics was also presented. One of the main findings of our study is that the difference between our calculated values of the flow rate and the estimated values of the flow rate in the ductile efferent was negligibly small. Moreover, our results can be implemented in the artificial cilia pumping systems in microchannels.

Micro Flow Sensor Based on Frequency Measurement of Micro Whistles

2012 ◽  
Vol 468-471 ◽  
pp. 2061-2064
Author(s):  
Yan Bin Di ◽  
Ying Miao
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volume Flow Rate ◽  
Frequency Measurement ◽  
Flow Sensor ◽  
Fluid Properties ◽  
Micro Flow ◽  
The Difference ◽  
Rate Frequency ◽  
Geometrical Dimensions

In this work, several millimeter sized micro whistles have been tested as potential frequency analog gas flow sensors. The characteristic curves of the whistles were systematically investigated as a function of geometrical dimensions, the kind of gas applied, and temperature. Both a micro¬phone and a PVDF foil were employed to record the frequencies. The relation be¬tween oscillation frequency and volume flow rate only shows a weak function of fluid properties and temperature. At a given flow rate, the difference of argon and nitrogen is 120 Hz on average, which is corresponding to 1.4 %. For air flow at a given flow rate, frequency rises approximately 380 Hz (2.73 %) per 10 °C. This kind of micro whistle could be employed as gas flow sensor which is insensitive to fluid properties.

Unsteady Analysis of Microvalves With No Moving Parts

2007 ◽  
Vol 23 (1) ◽  
pp. 9-14 ◽  
Author(s):  
C.-T. Wang ◽  
T.-S. Leu ◽  
J.-M. Sun
Keyword(s):  
Unsteady Flow ◽  
Flow Rate ◽  
Reverse Flow ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Pressure Amplitude ◽  
Flow Conditions ◽  
Unsteady Flow Condition ◽  
The Difference ◽  
Moving Parts

AbstractNo-moving-parts valves (NMPV) pumps produce the net volume flow due to the difference of pressure resistances between forward and reverse flow of a microchannel structure. NMPV has been developed by a number of research groups. However, most of NMPV in these studies are designed and based on steady state flow conditions. Little data is available regarding the NMPV in unsteady flow conditions. In this study, the performances of NMPV under both steady and unsteady flow conditions are investigated numerically. The NMPV used in this study is a diffuser-type microchannel with diffuser angle of 20° because of its outstanding production of net volume flow. By a series of numerical simulations, some useful results would be addressed for the performance of NMPV micropumps. First, Reynolds number confirmed by steady analysis should be greater than 10 (Re > 10) for the NMPV pumps to be more effective. Second, an optimal Strouhal number with maximum net volume flow rate is found at St = 0.013 for the unsteady flow condition. In addition, the relation between the driving pressure amplitude and net volume flow rate with a linear behavior found was helpful to the performance of the micropump system. According to these findings, it was easy for users to operate and design of NMPV micropumps.

scholarly journals Study of Four Passive Second Skin Façade Configurations as a Natural Ventilation System During Winter and Summer

2021 ◽  
Vol 28 (1) ◽  
pp. 94-105
Author(s):  
Youssef Hamidi ◽  
Mustapha Malha ◽  
Abdellah Bah
Keyword(s):  
Flow Rate ◽  
Fossil Fuels ◽  
Natural Ventilation ◽  
Climate Models ◽  
Energy Savings ◽  
Volume Flow Rate ◽  
Ventilation System ◽  
Volume Flow ◽  
Design Strategies ◽  
The Difference

The fight against climate change is a significant challenge, resulting mainly from the linear and extensive exploitation of natural resources, particularly fossil fuels. Its impacts are now recognized. The current climate models are neither sustainable nor ecological in economic and social terms, especially as we live in a century marked by galloping demography and urbanization. Researchers worldwide have paid great attention to passive solar design strategies such as double skin or Second Skin Façade.  From this point, the present work aims to contribute to a better understanding of the feasibility of using a passive façade as a useful technology for natural ventilation to achieve potential energy savings and improve thermal comfort and indoor air quality. For this purpose, a parametric study was conducted for a room with four different southern facade configurations in six Moroccan climatic zones; the difference between each lies in the vent's position in the entrance and exit. This process was done by using COMSOL Multiphysics software. Velocity and volume flow rate fields were analyzed. The proposed configurations provided an average volume flow rate between 200 m3/h and 400 m3/h for a surface of 1 m2 of southern façade with an air vent area of 0.1mx0.2m.

scholarly journals Saliva secretion difference before and after rinsing with baking soda on menopause women

2007 ◽  
Vol 19 (1) ◽  
Author(s):  
Dewi Anggraeni ◽  
Sri Tjahajawati ◽  
Rosiliwati Wihardja
Keyword(s):  
Statistical Analysis ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Survey Method ◽  
Average Volume ◽  
Saliva Secretion ◽  
Significant Difference ◽  
Before And After ◽  
The Difference

Menopause women can experience a decrease in saliva secretion (decrease). To understand the clear picture about saliva secretion, the volume, flow rate, pH and viscosity were then measured. The aim of this research was to obtain a picture about the difference of saliva secretion before and after rinsing with baking soda on menopause women. The type of the research used was a laboratory quasi-experiment with comparative descriptive form. The technique used in this research is the survey method, and samples were taken using the multistage cluster random sampling method, and t-student statistical analysis. This research was conducted with the saliva collected with spitting method on 45 menopause women. The results show that the average volume, flow rate, pH and viscosity before rinsing with baking soda was 1.79 ml, 0.18 ml/minute, 7.40 and 0.81 mm2/second. The average volume, flow rate, pH and viscosity after rinsing with baking soda were 2.66 ml; 0.27 ml/minute; 8.67 and 0.78 mm2/second. Statistical analysis t-student on α = 0.05 shows volume changes, flow rate, pH and saliva viscosity before and after rinsing with baking soda was 0.873; 0.086; 1.273 and 0.037 respectively. The conclusion shows a significant difference between saliva secretion before and after rinsing with baking soda, and saliva secretion after rinsing with baking soda on menopause women.

Establishing & Estimating Gas-Liquid Performance Characteristics of Multiphase Pumps

2021 ◽  
Author(s):  
Chidirim Enoch Ejim
Keyword(s):  
Flow Rate ◽  
Rotational Speed ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Operating Conditions ◽  
Gas Content ◽  
Two Phase ◽  
Pump Performance ◽  
Multiphase Pump ◽  
The Difference

Abstract Multiphase electric submersible pumps (ESPs) are used to produce gas and liquid in wells with high gas content. These pumps are operated at different speeds, and designed to handle flows with various gas volume fractions (GVFs). This study uses gas-liquid dimensionless parameters to obtain and compare the performance of conventional multiphase pumps. Knowledge of such techniques is important for production engineers, field operators and application engineers to ascertain pump performance for given gas-liquid operating conditions. Gas-liquid performance data for two multiphase pumps with 8.00-inch and 8.62-inch housing diameters were obtained from open literature. The inlet pressure, GVF and rotational speed ranges were 100 to 300 psig, 0 to 0.57, and 3000 to 3600 revolutions per minute (RPM), respectively. The total flow rates varied from 15000 to 60000 barrels per day (BPD). Euler turbomachinery principles for gas-liquid flows were applied to the data to obtain required dimensionless parameters and two-phase dimensionless performance curves for the pumps. The method was tested using dimensionless curves for a given operating condition to obtain pump performance at another operating condition. The results showed that for each rotational speed, the difference in dimensionless pressure between the multiphase pump discharge and inlet decreased with increasing mass-quality-weighted volume flow rate. For each weighted volume flow rate, the difference in pump discharge and inlet dimensionless pressures decreased with increasing intake GVF. The decrease with increasing intake GVF can range between a factor of 3 and 4, depending on the magnitude of the weighted volume flow rate. Using the 3000 RPM data, a two-phase (gas-liquid) dimensionless performance curve was obtained for one of the multiphase pumps with intake GVF and dimensionless volume flow rate parameter as the independent variables. The curve was used to estimate pump performance at 3600 RPM and then compared with the actual reference test data. For the second multiphase pump, two datasets at different intake pressures were used to obtain the effects of intake pressure. The performance for this multiphase pump was a function of dimensionless volume flow rate, intake GVF and intake gas-liquid density ratio. The maximum error in the estimated performance data was within 7%. Overall, the performance of multiphase pumps can be estimated using the technique in this study for the flow conditions analyzed. This study highlights the importance of obtaining dimensionless two-phase performance characteristics of multiphase pumps. Given that these pumps are frequently used in oilfield production operations, capability to determine the pressure boosting performance of the pumps, for given operating conditions, is important to field operating personnel and design engineers. This knowledge benefits the operator to optimally produce hydrocarbons from high gas-content wells and maximize the economic bottom line from the field asset.

Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE

1989 ◽  
Vol 47 ◽  
pp. 1000-1001
Author(s):  
Joe A. Mascorro ◽  
Gerald S. Kirby
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Succinic Anhydride ◽  
Volume Flow Rate ◽  
Mass Density ◽  
Uranyl Acetate ◽  
Volume Flow ◽  
Base Resin ◽  
And Performance ◽  
Acid Anhydrides

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.

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