Dynamic generation of power function gradient profiles in a universal microfluidic gradient generator by controlling the inlet flow rates

Lab on a Chip ◽  
2022 ◽  
Author(s):  
Gauri Paduthol ◽  
Teji Shenne Korma ◽  
Amit Agrawal ◽  
Debjani Paul
Keyword(s):  
Power Function ◽  
Functional Form ◽  
Inlet Flow ◽  
Flow Rates ◽  
Gradient Generator ◽  
Dynamic Generation

We report a two-inlet universal microfluidic gradient generator capable of generating gradient profiles of the functional form xp in the same device by controlling only the inlet flow rates. We...

scholarly journals Continuous-Flow Production of Liposomes with a Millireactor under Varying Fluidic Conditions

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1001
Author(s):  
Fatih Yanar ◽  
Ali Mosayyebi ◽  
Claudio Nastruzzi ◽  
Dario Carugo ◽  
Xunli Zhang
Keyword(s):  
Continuous Flow ◽  
Cost Effective ◽  
Storage Conditions ◽  
Inlet Flow ◽  
Flow Reactors ◽  
Ethanol Injection ◽  
Flow Rates ◽  
Liposome Size ◽  
Liposome Dispersion ◽  
Processing Steps

Continuous-flow production of liposomes using microfluidic reactors has demonstrated advantages compared to batch methods, including greater control over liposome size and size distribution and reduced reliance on post-production processing steps. However, the use of microfluidic technology for the production of nanoscale vesicular systems (such as liposomes) has not been fully translated to industrial scale yet. This may be due to limitations of microfluidic-based reactors, such as low production rates, limited lifetimes, and high manufacturing costs. In this study, we investigated the potential of millimeter-scale flow reactors (or millireactors) with a serpentine-like architecture, as a scalable and cost-effective route to the production of nanoscale liposomes. The effects on liposome size of varying inlet flow rates, lipid type and concentration, storage conditions, and temperature were investigated. Liposome size (i.e., mean diameter) and size dispersity were characterised by dynamic light scattering (DLS); z-potential measurements and TEM imaging were also carried out on selected liposome batches. It was found that the lipid type and concentration, together with the inlet flow settings, had significant effects on the properties of the resultant liposome dispersion. Notably, the millifluidic reactor was able to generate liposomes with size and dispersity ranging from 54 to 272 nm, and from 0.04 to 0.52 respectively, at operating flow rates between 1 and 10 mL/min. Moreover, when compared to a batch ethanol-injection method, the millireactor generated liposomes with a more therapeutically relevant size and size dispersity.

The Role of Mean Flame Anchoring on the Stability Characteristics of Syngas, Synthesis Natural Gas, and Hydrogen Fuels in a Turbulent Non-Premixed Bluff-Body Combustor

2019 ◽  
Author(s):  
Nikhil Ashokbhai Baraiya ◽  
Satynarayanan R. Chakravarthy
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Momentum Flux ◽  
Bluff Body ◽  
Flame Stabilization ◽  
Inlet Flow ◽  
Combustion Dynamics ◽  
Flow Rates ◽  
Inlet Flow Rate ◽  
The Difference

Abstract A lab-scale bluff body combustor is mapped for its stability and flame dynamics of non-premixed flames. The characteristics are observed across variations in the fuel composition, as well as in the inlet flow rate. The combustor is seen to exhibit markedly different dynamics for each of the varied fuel compositions. This behavior is explained on the basis of mean flame stabilization behavior and on the combined effects of the fuel-jet momentum flux and global equivalence ratio. It is seen that the H2 flames primarily act as a pilot source for secondary combustion of either CO or CH4. Further, it is seen that, the high momentum flux associated with H2-CO mixtures result in combustion near the wall and outside the bluff-body shear layers at low inlet flow rates. Whereas, at high inlet flow rates, the mean heat release rate is seen to stabilize closer to the injection holes as well as extend to near the bluff-body shear layer. This marked difference in flame stabilization is seen to have a drastic effect on the nature of oscillations inside the chamber. This is contrasted to H2-CH4 (synthesis natural gas) flames that exhibit stabilization inside the bluff-body wake at high inlet flow rate. The difference between H2-CH4 and H2-CO flames with regards to combustion dynamics is then explained as a result of the flame stabilization behavior, which is seen to be different across the varied fuel compositions. While H2-CH4 flame exhibits the well-known large wake structures responsible for combustion instability, H2-CO flame exhibits no such structures, owing to their stabilization point. Further analysis using pressure fixed phase instants reveal the difference in nature of combustion dynamics across the tested fuel compositions and are justified using the spatial Rayleigh index map.

scholarly journals Experimental Studies of Effect of Land Width in PEM Fuel Cells with Serpentine Flow Field and Carbon Cloth

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 471 ◽  
Author(s):  
Xuyang Zhang ◽  
Andrew Higier ◽  
Xu Zhang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Carbon Cloth ◽  
Pumping Power ◽  
Inlet Flow ◽  
Flow Rates ◽  
Reactant Flow ◽  
Land Width

Flow field plays an important role in the performance of proton exchange membrane (PEM) fuel cells, such as transporting reactants and removing water products. Therefore, the performance of a PEM fuel cell can be improved by optimizing the flow field dimensions and designs. In this work, single serpentine flow fields with four different land widths are used in PEM fuel cells to study the effects of the land width. The gas diffusion layers are made of carbon cloth. Since different land widths may be most suitable for different reactant flow rates, three different inlet flow rates are studied for all the flow fields with four different land widths. The effects of land width and inlet flow rate on fuel cell performance are studied based on the polarization curves and power densities. Without considering the pumping power, the cell performance always increases with the decrease in the land width and the increase in the inlet flow rates. However, when taking into consideration the pumping power, the net power density reaches the maximum at different combinations of land widths and reactant flow rates at different cell potentials.

NEURAL NETWORKS FOR THE OPTIMIZATION OF CRUDE OIL BLENDING

2005 ◽  
Vol 15 (05) ◽  
pp. 377-389 ◽  
Author(s):  
WEN YU ◽  
AMÉRICA MORALES
Keyword(s):  
Neural Networks ◽  
Crude Oil ◽  
Optimization Technique ◽  
Real Data ◽  
Oil Field ◽  
Inlet Flow ◽  
Flow Rates ◽  
History Data ◽  
Automation Systems ◽  
On Line

Crude oil blending is an important unit in petroleum refining industry. Many blend automation systems use real-time optimizer (RTO), which apply current process information to update the model and predict the optimal operating policy. The key unites of the conventional RTO are on-line analyzers. Sometimes oil fields cannot apply these analyzers. In this paper, we propose an off-line optimization technique to overcome the main drawback of RTO. We use the history data to approximate the output of the on-line analyzers, then the desired optimal inlet flow rates are calculated by the optimization technique. After this off-line optimization, the inlet flow rates are used for on-line control, for example PID control, which forces the flow rate to follow the desired inlet flow rates. Neural networks are applied to model the blending process from the history data. The new optimization is carried out via the neural model. The contributions of this paper are: (1) Stable learning for the discrete-time multilayer neural network is proposed. (2) Sensitivity analysis of the neural optimization is given. (3) Real data of a oil field is used to show effectiveness of the proposed method.

Methodology to Investigate the Hydraulic Characteristics of a Water-Powered Piston-Type Proportional Injector Used for Agricultural Chemigation

2018 ◽  
Vol 34 (3) ◽  
pp. 545-553 ◽  
Author(s):  
Pan Tang ◽  
Hong Li ◽  
Zakaria Issaka ◽  
Chao Chen
Keyword(s):  
Flow Rate ◽  
Calculation Model ◽  
Differential Pressure ◽  
Coefficient Of Determination ◽  
Inlet Flow ◽  
Flow Rates ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Inlet Flow Rate ◽  
Injection Ratio

Abstract. The proportional injector is commonly used in agricultural chemigation due to its relatively high injection ratio. A major challenge with the proportional injector is related to its dependence on differential pressure, which is significantly influenced by changes in the viscosity, and setting injection ratio. A series of experiments were conducted to investigate the influence of differential pressures, solution viscosities, and setting injection ratios on the inlet and injection flow rates of a D25RE2 proportional injector. A mathematical model was developed to represent the hydraulic performance of this proportional injector. Finally, the mathematical model was verified using four different kinds of chemicals (humic acid, urea ammonium nitrate 32% N, fosthiazate, and colza oil). The inlet flow rate increased significantly with increasing differential pressure and decreased with increasing setting injection ratio. Results showed that the highest operating differential pressure should not be greater than 0.15 MPa for the D25RE2 proportional injector. The inlet flow rate gradually decreased with increasing viscosity, and a quadratic function relationship was derived between the inlet flow rate and the viscosity. The injection flow rate decreased with increasing viscosity. However, the viscosity had a slight influence on the injection flow rate when it was lower than 20 mPa·s. Mathematical models for calculating the inlet and injection flow rates with the influence of viscosity were developed, respectively. The coefficient of determination and the root mean square error (RMSE) for inlet flow rate calculation model were 0.8316 and 143.36 kg h-1, respectively. The coefficient of determination and the RMSE for the injection flow rate calculation model were 0.9706 and 0.9520 kg h-1, respectively. The calculating formula of inlet flow rate had a satisfactory accuracy under low differential pressure and high setting injection ratio. The calculating formula of the injection flow rate had a good accuracy, which is useful for calculating the injection flow rate when injected with different kinds of solutions. The average deviations between calculated and experimental injection flow rates with injection ratios of 0.2%, 1.2%, and 2% were obtained as 4.96%, 4.66%, and 4.1% respectively, which indicated that the average deviations decreased with increasing setting injection ratio. Results from this study are useful for both designers and users to effectively manage agricultural chemigation system with the proportional injector. Keywords: Agriculture, Chemigation, Proportional injector, Hydraulic performance.

scholarly journals Single Needle Option: An Alternative to Dual-Needle Access in Erythrocytapheresis in Patients with Sickle Cell Disease

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4284-4284
Author(s):  
Teresa Munson ◽  
Jun Zhao ◽  
Esther Elise Knapp ◽  
Charmaine Du Toit ◽  
Ashok Raj ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Red Blood Cells ◽  
Sickle Cell ◽  
Vascular Access ◽  
Blood Cells ◽  
Red Cells ◽  
Cell Disease ◽  
Inlet Flow ◽  
Flow Rates ◽  
Hemoglobin S

Abstract Background: Erythrocytapheresis or red cell exchange (RCE) is an invaluable treatment option for patients with complications related sickle cell disease, including acute stroke, stroke prevention, acute chest syndrome, and recurrent pain crisis. The procedure entails the removal of each patient's red blood cells containing the abnormal sickle hemoglobin and replacing them with normal red blood cells carrying non-sickled hemoglobin. Adequate vascular access is essential for erythrocytapheresis to allow for high flow rates and various forms of access are used including peripheral veins and central venous access devices. Our center typically uses a single vortex port (Angiodynamics, Walnut Creek, CA) with placement of a peripheral IV at time of procedure in order to maintain a circuit for exchange. Using peripheral access reliably becomes particularly difficult in young patients and those that require multiple access over time due to scaring. To ensure a successful procedure in patients with poor peripheral access, a single-needle (SN) option for TPE (SN-TPE) that is available on Spectra Optia (Terumo BCT, Lakewood, CO) was used. The single-needle procedure utilizes intermittent, rather than continuous, flow, and thus requires extra procedure run time. One discontinuous cycle consists of "exchanging red cells," which is the drawing of blood and removal of the red cells, and "adjusting the volume in the reservoir," which is the returning of blood. These cycles continue until the procedure is complete. This procedure allows us to continue RCE in a select number of patients with poor vascular access. Methods: We evaluated our institutional experience on patients treated using single-needle RCE. In addition, information regarding each RCE session was collected including duration of procedure and inlet flow rate. Results: An average of 45 RCE procedures are performed each month. Patients are scheduled every 3 to 8 weeks, with an average of every 4-5 week frequency. We started the Single Needle option in July of 2019 on 3 patients: one adult aged patient and 2 pediatric patients. By the end of 2019 we had perform a total of 27 SN procedures. In 2020, we performed a total of 112 SN procedures, average of 9 procedures each month. As of the first 6 months of 2021, we have completed 35 SN procedures, averages 6 a month. In patients undergoing single needle exchange we were able to increase inlet flow rates from an average of 30-50ml/min to 60-80ml/min. This decreased the duration of run times from 120-198 min to 77- 119 min. Pre and post hemoglobin S% was comparable between dual and single exchange patients and there was no change in the interval between RCE sessions. Conclusion: With our increasing experience with single-needle RCE, our findings suggest that RCE can be successfully completed using the single-needle option with no impact on pre- and post-exchange hemoglobin S% levels. There was a reduction in the total length of procedure due to ability to maintain higher inlet rates and decreased time to obtain access for RCE. The single needle option also improved patient satisfaction due to more reliable access and negating need for peripheral IV access. Disclosures Munson: Terumo Medical Corporation: Consultancy, Honoraria, Speakers Bureau. Raj: Forma therapeutics: Consultancy; Terumo Medical Corporation: Honoraria, Speakers Bureau; Global biotherapeutics: Speakers Bureau.

scholarly journals Study on Characteristics of Heat Transfer and Flow Resistance in Random Porous Foam Metal

2019 ◽  
Vol 128 ◽  
pp. 04010
Author(s):  
Aiqiang Chen ◽  
Sizhong Gu ◽  
El Achkar Georges ◽  
Rachid Bennacer ◽  
Bin Liu
Keyword(s):  
Heat Transfer ◽  
Flow Direction ◽  
Homogeneous Model ◽  
Low Flow ◽  
Bottom Plate ◽  
Random Structure ◽  
Plate Temperature ◽  
Inlet Flow ◽  
Flow Rates ◽  
Foam Metal

Porous foam metal has great application prospects in the field of compact heat exchangers. The characteristics of heat transfer and resistance for foam metal with random structure and different porosities (30%, 50%, 70% and 90%) were studied by finite element method in this study. The generated foam structures can be considered as homogeneous model and has better heat exchange capacity at higher inlet flow rate, and the boundary layer can develop well along the flow direction. The open–cell foammetal structure has a uniform heat transfer perpendicular to the flow direction. The bottom plate temperature of the low–porosity structure is more uniform at low flow rates. The intermediate porosities (50% and 70%) at high flow rates has a higher uniformity. As the porosity decreases, the internal pressure increases significantly and the pressure loss also becomes significantly larger. The corresponding optimal porosity is 57%, 66% and 76% at inlet flow rates of 0.001 m/s, 0.01 m/s and 0.1 m/s, respectively.

Numerical and experimental investigation of turbocharger compressor low-end performance improvement using a variable geometry inlet orifice

2020 ◽  
pp. 146808742095109
Author(s):  
Ben Zhao ◽  
Qingjun Zhao ◽  
Wei Zhao ◽  
Xiaorong Xiang ◽  
Xiaoyong Zhou
Keyword(s):  
Variable Geometry ◽  
Peak Efficiency ◽  
Flow Area ◽  
Inlet Flow ◽  
Flow Rates ◽  
Area Reduction ◽  
Numerical Predictions ◽  
Percentage Points ◽  
Compressor Performance ◽  
Compressor Efficiency

Variable geometry orifice located upstream of a centrifugal impeller has been proposed to improve compressor low-end performance, by reducing compressor inlet flow area. The inlet flow area reduction is achieved by actuating the orifice flow area. The effects of the flow area reduction on compressor performance and the physical mechanisms controlling performance were investigated in the current work using numerical simulations and physical experiments. At the investigated compressor speed, with reduced inlet flow area, compressor efficiency at high flow rates is decreased by 2.01 percentage points based on the numerical predictions and by 6.47 percentage points based on the physical data. At low flow rate, however, compressor efficiency can be improved by 2.26 percentage points based on the numerical predictions and by 2.88 percentage points based on the physical data. Besides the efficiency, the inlet flow area reduction shifts the compressor stability limit toward the lower flow rate by 9.09% based on the numerical results and 41.13% based on the physical experiment and improves the compressor peak pressure ratio by 0.55% based on both the numerical and experimental data. At the flow rates lower than the peak efficiency point, it is beneficial to actuate the orifice to improve the compressor low-end performance. At flow rates higher than the peak efficiency point, it is necessary to deactivate the orifice to avoid the inlet flow area reduction that induces flow loss and degrades compressor performance.

scholarly journals Computational Hemodynamic Analysis for the Diagnosis of Atherosclerotic Changes in Intracranial Aneurysms: A Proof-of-Concept Study Using 3 Cases Harboring Atherosclerotic and Nonatherosclerotic Aneurysms Simultaneously

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Shin-ichiro Sugiyama ◽  
Hidenori Endo ◽  
Kuniyasu Niizuma ◽  
Toshiki Endo ◽  
Kenichi Funamoto ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intracranial Aneurysms ◽  
Patient Specific ◽  
Proof Of Concept ◽  
Inlet Flow ◽  
Flow Rates ◽  
Concept Study ◽  
Relative Residence Time ◽  
The Mean ◽  
Atherosclerotic Changes

This was a proof-of-concept computational fluid dynamics (CFD) study designed to identify atherosclerotic changes in intracranial aneurysms. We selected 3 patients with multiple unruptured aneurysms including at least one with atherosclerotic changes and investigated whether an image-based CFD study could provide useful information for discriminating the atherosclerotic aneurysms. Patient-specific geometries were constructed from three-dimensional data obtained using rotational angiography. Transient simulations were conducted under patient-specific inlet flow rates measured by phase-contrast magnetic resonance velocimetry. In the postanalyses, we calculated time-averaged wall shear stress (WSS), oscillatory shear index, and relative residence time (RRT). The volume of blood flow entering aneurysms through the neck and the mean velocity of blood flow inside aneurysms were examined. We applied the age-of-fluid method to quantitatively assess the residence of blood inside aneurysms. Atherosclerotic changes coincided with regions exposed to disturbed blood flow, as indicated by low WSS and long RRT. Blood entered aneurysms in phase with inlet flow rates. The mean velocities of blood inside atherosclerotic aneurysms were lower than those inside nonatherosclerotic aneurysms. Blood in atherosclerotic aneurysms was older than that in nonatherosclerotic aneurysms, especially near the wall. This proof-of-concept study demonstrated that CFD analysis provided detailed information on the exchange and residence of blood that is useful for the diagnosis of atherosclerotic changes in intracranial aneurysms.

scholarly journals B3010: A Boosted TSI 3010 CPC for Airborne Studies

2018 ◽  
Author(s):  
David Picard ◽  
Michel Attoui ◽  
Karine Sellegri
Keyword(s):  
High Altitude ◽  
Detection Efficiency ◽  
Important Application ◽  
Continuous Operation ◽  
Inlet Flow ◽  
Flow Rates ◽  
Deep Knowledge ◽  
Calibration Methods ◽  
Wide Availability ◽  
Standard Calibration

Abstract. In the present paper, we expose how we boosted the performances of a commercial CPCmodel TSI 3010 to detect particles as small as 1.5 nm, while preserving the robustness and reliability of the original instrument. The TSI 3010 was selected for its wide availability on the second-hand market, our deep knowledge of its internals, and its large internal butanol reservoir that allows continuous operation for several hours without refill, which is well suited to airborne campaigns. The CPC described in this study is called B3010 hereafter, where the B stands for boosted. We provide an evaluation of its performances down to 1 nm using standard calibration methods, and comparisons with ultrafine CPCs (TSI 3025 and TSI 3776). One important application of the B3010 being high-altitude measurement stations and airborne studies, the instrument's detection efficiency was quantified for various inlet flow rates and pressures.

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