T-shaped Channel Research Articles

A Novel T-Shape Channel With an Inverted-T Nano-Cavity Label-Free Detection Using Si:HfO2 Ferroelectric DGDM-JLTFET as a Biosensor—A Simulation Study

A Novel T-Shape Channel With an Inverted-T Nano-Cavity Label-Free Detection Using Si:HfO₂ Ferroelectric DGDM-JLTFET as a Biosensor—A Simulation Study

Two-Phase Fluid Dynamics in Proton Exchange Membrane Fuel Cells: Counter-Flow Liquid Inlets and Gas Outlets at the Electrolyte-Cathode Interface

Abstract This study uses a volume of fluid method to model two-phase interactions in a T-shaped GDLand gas channel (GC) assembly, with GDL geometry derived from nano-computer tomography. his research investigates the impact of the size and shape of liquid invasion on the liquid-gas behavior in the cathode GDL and GC using five liquid injection configuration. Simulations also incorporate GDLgas outlets, integrating them with a tailored liquid inlet setup. Comparisons of simulations with and without air outflow show distinct counter-flow interactions, highlighting variations in water distribution and discrepancies in two-phase transport across the GCs.

Pressure-driven formation of sub-femtoliter droplets in constricted T-shaped nanofluidic channel and application to isolation and counting of single nanoparticles

Nanofluidics has developed, enabling the analysis of single nanoparticles such as viruses and macromolecules using nanochannels. However, since nanoparticles migrate randomly by Brownian motion with displacements comparable to the nanochannel size, it is difficult to array and process nanoparticles individually in continuous phase flows with biological analyte concentrations of pM–nM. The present study developed a method to generate aqueous droplets of 102 aL–100 fL volumes in an organic phase in a nanochannel by pressure-driven flow control, and applied the method to the isolation of single nanoparticles with 101−102 pM concentrations. A T-shaped nanochannel with a narrow constriction section was proposed to locally enhance the shear force to form smaller droplets by 102 kPa external pressure, without increasing the pressure loss by downscaling the channel. The proposed channel design was validated, droplets with 0.8–1.0 fL volumes were formed with pL/min flow rates at Ca = 0.5–1.4 × 10−3, and the dynamics of droplet generation was well characterized by the linear scaling law. Using the developed device, encapsulation and counting of single fluorescent nanoparticles and single fluorescently-labeled DNA molecules in droplets were successfully demonstrated. This work will contribute to the development of droplet nanofluidics and ultrasmall analytical applications.

Energy and exergy performance improvement of coupled PV–TEG module by using different shaped nano-enhanced cooling channels

In this study, impacts of using different cooling channels (L, T and U-shaped) on the energy and exergy performances of combined PV/TEG (photovoltaic/thermoelectric generator) unit are numerically assessed by using FEM based three dimensional high fidelity computational simulations. Cooling performance is boosted by using ternary nanofluid in the channels. The study is conducted for a range of Reynolds numbers (Re, between 50 and 500), nanofluid cooling inlet temperatures (between 15 °C and 23 °C), and nanoparticle loading amounts (between 0 and 3%). Evaluations are done on average PV-cell temperature, PV/TEG output powers, exergy efficiency, improve potential (IP), and sustainability index (SI). U-shaped and T-shaped channels are found to offer the greatest and worst cooling performances among various cooling channels. When comparing the lowest and maximum Re cases, the average temperature drops for PV cells are 3.54 °C for T channel and 2.55 °C for U channel. Exergy efficiency is determined to be 14.2% with T-channel at Re=50 and 14.6% with U-channel at Re=500. Taking into consideration different channels, an increase in the inlet temperature from 15 °C to 23 °C leads to an average rise in cell temperature of 6 °C. The IP rises with coolant inlet temperature while using T-channel. SI values fall as input temperature increases, although values between 1.164 and 1.175 may be achieved by using different cooling channels. Using nanofluid with higher loading results in higher exergy efficiency when comparing exergetic performances, with U-channel design exhibiting the highest performance. For the range of parameters considered, the coolant inlet temperature at the channel entry has the highest effect on PV cell temperature reduction; 8.5 °C of temperature reduction is feasible. By employing U-channel cooling, the maximum value of Re, the highest loading of nanoparticles, and the lowest inlet temperature yield the best exergy efficiency. The best and worst situations’ respective exergy efficiencies are determined to be 15% and 14.1%. Utilizing T-channel cooling with water at a flow flow rate and a higher input temperature is the scenario with the biggest potential for exergy improvement; the value is 2.9. When different operational parameters are varied, the SI falls between 1.176 to 1.16.

Understanding droplet formation in T-shaped channels with magnetic field influence: A computational investigation

This study investigates the production of ferrofluid droplets in a T-junction geometry using the level set method and magnetic force manipulation in the three-dimensional. The analysis reveals key insights into droplet formation processes in four stages: entering, blocking, necking, and detachment. The results show that increasing the Capillary number leads to a significant decrease in volume for non-ferrofluid droplets. Application of a magnetic force enhances the balance of forces during droplet formation, directly impacting droplet volume. Moreover, increasing the magnetic Bond number substantially increases droplet volume, with a more pronounced effect at lower Capillary numbers. Modifying magnetic properties influences droplet volume, with doubling the magnetization results in a significant volume increase. Overall, magnetic forces emerge as a crucial control parameter for droplet volume in ferrofluid systems, offering potential applications in droplet-based technologies and microfluidic devices.

Reduced OFF-state current and suppressed ambipolarity in a dopingless vertical TFET with dual-drain for high-frequency circuit applications

In this article, a dopingless TFET with dual-drain and reversed T-shaped channel (DLVIT-TFET) is investigated to offer improvement in ON-state current (IOn) along with the reduction in OFF-state leakage current (IOff) and in ambipolarity. The investigated device has a dual channel region which helps in improving the on-state parameters like IOn and subthreshold swing (SS) due to the extended tunneling area. The inverted T-shaped channel minimizes the charge carriers to tunnel during the off-state, thereby reducing the magnitude of IOff. The results obtained from 2D TCAD simulation show that the investigated device provides ∼1 order of improvement in IOn and ∼3 orders of improvement in IOff. Furthermore, DLVIT-TFET offers an ∼3 orders of improvement in ambipolar current (IAmb) due to a reduction in peak electric field at channel-drain interface caused by splitting of drain potential at ambipolar state. Moreover, various analog/RF parameters such as transconductance (gm), gate parasitic capacitance (Cgd, and Cgs), cut-off frequency (fTmax), gain-bandwidth product (GBP), transconductance-frequency product (TFP) and transit time (τ) are found to be improved in DLVIT-TFET compared to the conventional DL-TFET. In addition, the transient analysis of DLVIT-TFET based inverter is analyzed, which shows improvement in the parameters like propagation delay and voltage swing. Finally, reliability of the investigated device is discussed by considering the effect of interface trap charges (ITCs) and variation in ambient temperature and it is observed that DLVIT-TFET is more immune to such defects and environmental factors than the conventional one.

A new coaxial flow-through probe for electromembrane extraction of methadone from clinical samples on-line coupled to capillary electrophoresis

BackgroundA new design of a flow-through coaxial electromembrane extraction (EME) probe that can be on-line coupled with CE instrument is described and tested. The supporting base of the probe is a PDMS microchip with T-shaped channels into which two coaxially arranged capillaries for inlet and outlet solutions are inserted. The extraction part of the probe is a porous polypropylene hollow fiber, sealed at one end and modified with nitrophenyloctyl ether (NPOE) extraction fluid. The internal volume of the extraction probe is 1.1 μL. ResultsThe EME probe was tested on laboratory samples and methadone was extracted into 3.0 M AcOH as acceptor. The concentration dependence was linear in the range of 0.1–1.0 μg mL−1 at EME 300 s/150 V and in the range of 0.5–10.0 μg mL−1 at EME 100 s/150 V. The enrichment factor was greater than 30 and the LOD was 0.21 μg mL−1. The EME of methadone in clinical samples showed a linear concentration dependence in human urine and a nonlinear concentration dependence in serum. The distribution of methadone in each phase of the extraction system and the effect of extraction membrane thickness on the enrichment factor were studied. The EME probe can be applied repeatedly. SignificanceThe supporting base of EME probe and flow gating interface (FGI) are realized by a microfluidic PDMS microchips cast in the laboratory without the use of lithography. A supporting PDMS chip with coaxially arranged capillaries and extraction membrane forms a compact analytical instrument. The entire EME/CE analysis process is performed on a laboratory-made instrument and automated by LabView.

Physics based model development of a double gate reverse T-shaped channel TFET including 1D and 2D band-to-band tunneling components

In this article, a Double gate reverse T-shaped channel tunnel field effect transistor (DG-RT-TFET) is mathematically modeled. The TFET has the potential for exhibiting various types of tunneling mechanisms. The modeled device encompasses both 1D and 2D Band-to-Band (BTBT) tunneling components, with each component developed in the epi-channel and channel, respectively. The study reveals that the 2D BTBT components exhibit greater dominance in the lower gate bias or subthreshold region, while the 1D BTBT becomes more prominent at higher gate bias voltages. By incorporating both models, a more comprehensive understanding of the DG-RT-TFET behavior can be achieved. To ensure the accuracy and reliability of the developed model, all model parameters are calibrated using the TCAD-sentaurus simulator. By comparing the results obtained from the developed model with the simulation results, it is concluded that the developed model for the DG-RT-TFET is suitable for capturing the device behavior and characteristics.

Modeling and Evaluating the Performance of a Split-Gate T-Shape Channel DM DPDG-TFET Biosensor for Label-Free Detection

Modeling and Evaluating the Performance of a Split-Gate T-Shape Channel DM DPDG-TFET Biosensor for Label-Free Detection

Design and Performance Analysis of N+ Pocket-Doped Vertical DMDGDP TFET with T-Shape channel for Sensitivity Improvement---As a Biosensor

Design and Performance Analysis of N+ Pocket-Doped Vertical DMDGDP TFET with T-Shape channel for Sensitivity Improvement---As a Biosensor

Optical Performance of the Double Gate Reverse T-Shaped Channel TFET in Near Visible Light Photodetector

Optical Performance of the Double Gate Reverse T-Shaped Channel TFET in Near Visible Light Photodetector

Thermal and phase change process in a branching T-channel under active magnetic field and two rotating inner cylinders: Analysis and predictions by radial basis neural networks

Effects of combining the use of a magnetic field with rotating cylinders on the thermal processes and phase transitions in a T-shaped branching channel are examined. In the vertical channel, a PCM-packed bed zone is used, and rotating cylinders are used in both the vertical and horizontal channels. For a range of rotational Reynolds numbers (Rew between −300 and 300), Hartmann numbers (Ha between 0 and 80), and cylinder sizes (Rc1 and Rc2 between 0.01H and 0.2H), investigations are conducted for the effects of coupled forced flow, magnetic field, and rotating cylinder interactions on the efficiency of the thermal and phase change processes. When there is no magnetic field, the entire transition time (TF) may be lowered and at Rew=2000, the TF is reduced by about 42.5% in comparison to a stationary cylinder case (Rew=0). Employing rotations at the fastest speed results in a 26% boost in heat transfer. Thermal performance increases become 181% and 205% at Rew=0 and Rew=−2000, respectively, but the TF value drops by around 31.5% and 17.5% when highest magnetic field strength is considered. When magnetic field and a horizontal channel cylinder are employed, the T-channel system operates most well in terms of phase change and heat transfer process. Fast and accurate predictions of the dynamic aspects of the phase change process are obtained and the full phase transition time is correctly calculated by using the radial basis neural network technique.

Linearity and RF analysis of double gate reverse T-shaped TFET with L-shaped pocket across the Si-Ge source region

In this work, a comprehensive investigation of the twin gate or double gate reverse T-shaped channel TFET (RT-DG-TFET) along with the heavily doped pocket at the source-channel interface is portrayed. Here the pockets have been placed in various places on the device like vertical and horizontal pockets across the source and the channel region, a pocket at the center of the source, a pocket near to tunneling junction, and an L-shaped pocket across the source-channel interface. All these structures are investigated and the pocket is doped with P-type impurities. Linearity and RF analysis are investigated using the Synopsis TCAD Sentaurus tools and compared among all these structures. The L-shaped pocket shows better results compared to others.

Heat and mass transfer efficiency in the T-Shaped geometry: Entropy generation analysis

Thermodynamic analysis of energy efficiency, especially those utilizing the second law ofthermodynamics, is focus of scientific inquiry, particularly given the interest in the efficient use of heatedenergy sources. In this work, we characterize the geometry in terms of entropy generation witch due tothe heat transfer and fluid friction as function of generalized Reynolds number under the effects ofdifferent inlet temperatures.This work has been performed for the important parameters in the following ranges: generalizedReynolds number (Reg = 1 to 60). As generalized Reynolds number increases, the entropy generation dueto heat transfers decreases, which reveal that the effect of the generalized Reynolds number on heattransfer performance is substantial. These results verify that the T-shaped channel can effectively enhancethe heat transfer performance for all cases. Overall, the entropy generation and synergy angle aresignificant characteristics to consider when building micromixers for thermal efficiency and misciblefluid mixing.

Droplet microfluidic chip for precise monitoring of dynamic solution changes

In this work, an automated microfluidic chip that uses negative pressure to sample and analyze solutions with high temporal resolution was developed. The chip has a T-shaped channel for mixing the sample with a fluorescent indicator, a flow-focusing channel for generating droplets in oil, and a long storage channel for incubating and detecting the droplets. By monitoring the fluorescence intensity of the droplets, the device could detect changes in solution accurately over time. The chip can generate droplets at frequencies of up to 42 Hz with a mixing ratio of 1:1 and a temporal resolution of 3–6 s. It had excellent linearity in detecting fluorescein solution in the concentration range 1–5 μM. This droplet microfluidic chip provides several advantages over traditional methods, including high temporal resolution, stable droplet generation, and faster flow rates. This approach could be applied to monitoring calcium ions with a dynamic range from 102 to 107 nM and a detection limit of 10 nM.

Effect of Wall Oscillation Period on Fluid Flow in Branched Channel with a Moving Indentation

The numerical simulation of two-dimensional fluid flow in T-shaped and Y-shaped channels having a single moving indented wall is performed by the finite element method in the Arbitrary Lagrangian-Eulerian frame. The motion of the indented wall is defined as a hyperbolic function, and it is located at a small segment at the bottom wall in the parent channel. The smallest value of the wall oscillation period causes the waviest core flow in the main channel, resulting in bigger vortices and greater flow separation region in the branches, especially during the outward indentation motion. This flow disturbance pattern is found more severe in T-channel as compared to that of in Y-channel.

Performance Investigation of a Vertical TFET with Inverted-T Channel for Improved DC and Analog/Radio-Frequency Parameters

In this manuscript, a novel line tunneling based gate-on-source-only TFET with inverted T-shaped channel (ITGOSO-VTFET) is proposed and investigated using Synopsis TCAD 2-D simulator. The GOSO configuration along with dual counter-doped pockets (CDP) improve the ON-state current by enhancing the tunneling rate of charge carriers at source/channel interface while inverted T-shaped channel helps the proposed device in reducing the OFF-state (IOFF) and ambipolar (IAMB) currents. In comparison with double-gate (DG) and GoSo-CDP TFET, the order of IOFF (IAMB) in ITGOSO-VTFET are found to be improved by ∼6 (∼4) and ∼7(∼3), respectively. Furthermore, the impact of varying design parameters is analyzed in order to obtain the optimized performance of the proposed device. Apart from improvement in DC performance, ITGOSO-VTFET is also found to offering a much better analog/RF performance in terms of various parameters like gm, fT, TFP, GBP, and τ, which eventually makes the proposed device more suitable for low power and high-speed applications.

Modeling and Performance Analysis of a Split-Gate T-Shape Channel DM DPDG-TFET Label-Free Biosensor

This article proposes, for the first time, a split-gate T-shape channel dielectrically modulated (DM) double-gate TFET (DGTFET) with a drain pocket (DP). This device can be used as a label-free biosensor. The analytical model for DM DPDG-TFET has been developed and it has been validated against commercial simulation software (Silvaco TCAD). This article intends to focus both on the sensitivity of the biosensor and its performance as a tunnel field-effect transistor (TFET) device. This has been accomplished by improvisations in the channel shape. The performance of the device has thoroughly been investigated in terms of threshold voltage, subthreshold slope, ON current, and OFF current. Due to the novel design, the proposed TFET possesses higher sensitivity, higher <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ {\text{ON}}}/{I}_{ {\text{OFF}}}$ </tex-math></inline-formula> current ratio, and lower subthreshold slope. The inclusion of DP at the drain–channel junction proves to be a successful way to remove the ambipolarity completely. The high ON current without any ambipolarity has been achieved by optimizing the DP length and its doping concentration. The proposed T-shape DM DPDGTFET proves itself to be superior to several reported devices in terms of both biosensor as well as field-effect transistor (FET) device. The presence and absence of charge of various biomolecules are taken into consideration for evaluation of device sensitivity as a label-free biosensor.

Tesla Valve-Based Flexible Microhybrid Chip with Unidirectional Flow Properties.

Flexible microfluidic chips have good application prospects in situations with easy bending and complex curvature. An important factor affecting the flexible microfluidic chip is its structural complexity. For example, the hybrid chip includes flow channels, mixing chambers, and one-way valves. How to achieve the same function with as few structures as possible has become an important research topic at present. In this paper, a Tesla valve micromixer with unidirectional flow characteristics is presented. A passive laminar flow Tesla valve micromixer is fabricated through 3D printing technology and limonene dissolution method. The main process is as follows: First of all, high impact polystyrene (HIPS) material was employed to make the Tesla valve channel mold. Second, the channel mold was dissolved in the limonene solvent. The mold of Tesla micromixer is made of HIPS material, the mixing experiment displace that the Tesla valve micromixer is characterized by unidirectional flow compared with the common T-shaped planar channel. At the same time, the 5-AAC Tesla valve micromixer can increase the mixing efficiency to 87%. By using four different groove structures and different flow rates of the mixing effect experiment, the conclusion is that the mixing efficiency of the 6-AAC Tesla valve micromixer is up to 0.89 when the flow rate is 2 mL/min. The results manifest that the Tesla valve structure can effectively improve the mixing efficiency.

Spontaneous Ignition of Cryo-Compressed Hydrogen in a T-Shaped Channel System

Sudden releases of pressurised hydrogen may spontaneously ignite by the so-called “diffusion ignition” mechanism. Several experimental and numerical studies have been performed on spontaneous ignition for compressed hydrogen at ambient temperature. However, there is no knowledge of the phenomenon for compressed hydrogen at cryogenic temperatures. The study aims to close this knowledge gap by performing numerical experiments using a computational fluid dynamics model, validated previously against experiments at atmospheric temperatures, to assess the effect of temperature decrease from ambient 300 K to cryogenic 80 K. The ignition dynamics is analysed for a T-shaped channel system. The cryo-compressed hydrogen is initially separated from the air in the T-shaped channel system by a burst disk (diaphragm). The inertia of the burst disk is accounted for in the simulations. The numerical experiments were carried out to determine the hydrogen storage pressure limit leading to spontaneous ignition in the configuration under investigation. It is found that the pressure limit for spontaneous ignition of the cryo-compressed hydrogen at temperature 80 K is 9.4 MPa. This is more than 3 times larger than pressure limit for spontaneous ignition of 2.9 MPa in the same setup at ambient temperature of 300 K.