Uniform Channel Research Articles

Research on Resource Allocation Algorithm for Non-Orthogonal Multiple Access Visible Light Communication

In order to satisfy the large-scale access of visible light communication (VLC) users, as well as the demand for user request rate, the resource allocation problem of visible light communication with drone-assisted non-orthogonal multiple access (NOMA) technique is investigated. An efficient scheme for joint optimization of power allocation and access point (AP) location is proposed. According to the state of user channel information, a user pairing strategy with uniform channel gain difference for any number of users is designed, and an objective function of maximizing the average user data rate with constraints is constructed. For this non-convex NP-hard problem, the optimization problem with constraints is transformed into an optimization problem without constraints by introducing the idea of a penalty function and then solved by the Harris Hawk Optimization (HHO) algorithm based on the nonlinear energy convergence factor, and ultimately, the optimal user power allocation factor, as well as the location of the AP, are found. The simulation results show that the scheme in this paper can improve the average user data rate better compared to other classical schemes. The system performance of the HHO algorithm is improved by about 20.31% compared to the Particle Swarm Optimization (PSO) algorithm. The HHO algorithm based on the nonlinear energy convergence factor improves the convergence speed by about 50% compared to the classical HHO algorithm.

High-performance supercapacitor of ZnO-incorporated structurally modified g-C3N4 with circular mesoporous channels attained via a template-free approach

Abstract Here, the superior structural features of graphitic carbon nitride (g-C3N4) in combination with integrated mesoporous channels have been explored for its use as a supercapacitor electrode material. A facile template-free strategy is adopted for the preparation of ZnO-incorporated modified g-C3N4 nanocomposite, where material characterization via x-ray difraction, Fourier transfrom infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy analysis revealed the presence of structurally modified g-C3N4 having uniform circular mesoporous channels with well-dispersed ZnO with strong Zn–C and Zn–N interactions. The electrical double-layer capacitance together with the pseudocapacitance of the ZnO/g-C3N4 electrode material resulted in improved performance, leading to a specific capacitance of 146.3 F g−1 at a current density of 0.5 A g−1; an increased capacitance is observed in 5000 repeated charge–discharge cycles. A symmetric coin cell supercapacitor fabricated from the material displayed an energy density of 38.8 mWh kg−1 at a power density of 4259 mW kg−1. Additionally, the long life of 6000 cycles (retaining 100% specific capacitance) exhibited by the coin cell supercapacitor further indicates the promising energy storage nature of the ZnO-incorporated modified g-C3N4 mesoporous nanoarchitecture. Real life application of the ZnO/g-C3N4-derived supercapacitor is illustrated by lighting up a green LED with a series connection of four coin cells.

In‐Situ Self‐respiratory Solid‐to‐hydrogel Electrolyte Interface Evoked Well‐Distributed Deposition on Zinc Anode for Highly Reversible Zinc‐ion Batteries

The aqueous zinc‐ion batteries (AZIB) have emerged as a promising technology in the realm of electrochemical energy storage. Despite its potential advantages in terms of safety, cost‐effectiveness, and inherent safety, AZIB faces significant challenges. Issues attributed to unsupported thermodynamics and non‐uniform potential distribution and deposition, present formidable obstacles that necessitate resolution. To tackle these challenges, a novel strategy adapting hybrid organic‐inorganic in‐situ derived solid‐to‐hydrogel electrolyte interface (StHEI) has been developed from coordination reactions and self‐respiratory process, establishing uniform diffusion channels by ion bridges and accelerating ion transport. Self‐respiratory pattern of StHEI realized through in‐situ inorganic component conversion further prolongs the protecting duration, which effectively mitigates corrosion and passivation but enhance the mechanical properties of the StHEI measured through Young’s modulus. This novel StHEI promotes well‐distributed potential lines within the Helmholtz regions. Zn2+ are finally induced to deposit and nucleate in a compact, fine, and uniform manner. Asymmetrical batteries assembled with the modified Zn electrode and bare Zn exhibit exceptional stability over 3000 h (1 mA cm‐2‐ 0.5 mAh cm‐2). The asymmetrical Cu//Zn cell achieved an outstanding average Coulombic efficiency (CE) of 99.6% over 1200 cycles.

In-Situ Self-respiratory Solid-to-hydrogel Electrolyte Interface Evoked Well-Distributed Deposition on Zinc Anode for Highly Reversible Zinc-ion Batteries.

The aqueous zinc-ion batteries (AZIB) have emerged as a promising technology in the realm of electrochemical energy storage. Despite its potential advantages in terms of safety, cost-effectiveness, and inherent safety, AZIB faces significant challenges. Issues attributed to unsupported thermodynamics and non-uniform potential distribution and deposition, present formidable obstacles that necessitate resolution. To tackle these challenges, a novel strategy adapting hybrid organic-inorganic in-situ derived solid-to-hydrogel electrolyte interface (StHEI) has been developed from coordination reactions and self-respiratory process, establishing uniform diffusion channels by ion bridges and accelerating ion transport. Self-respiratory pattern of StHEI realized through in-situ inorganic component conversion further prolongs the protecting duration, which effectively mitigates corrosion and passivation but enhance the mechanical properties of the StHEI measured through Young's modulus. This novel StHEI promotes well-distributed potential lines within the Helmholtz regions. Zn2+ are finally induced to deposit and nucleate in a compact, fine, and uniform manner. Asymmetrical batteries assembled with the modified Zn electrode and bare Zn exhibit exceptional stability over 3000 h (1 mA cm-2- 0.5 mAh cm-2). The asymmetrical Cu//Zn cell achieved an outstanding average Coulombic efficiency (CE) of 99.6% over 1200 cycles.

Enhancing retention of biological fluid transport of magnetized thermal radiative pseudoplastic nanofluid with double diffusion convection, viscous dissipation and boundary slips

This study investigates how thermal radiation, viscous dissipation, double-diffusive convection, and slip boundaries collectively affect the peristaltic movement of a magneto-pseudoplastic nanofluid within a uniform channel. The inclusion of slip boundary conditions at the channel walls helps to accurately represent the flow behavior of the nanofluid near these boundaries. The magneto-pseudoplastic nanofluid exhibits peculiar rheological features to flow dynamics due to pseudoplastic characteristics of nanoparticles in its composition and exposure to magnetic force. The mathematical formulation of motion equations is done through appropriate technique combining the properties of heat radiation, magnetic flux, double diffusion convection, and rheological features. The equation is further simplified by suitable method. The current study aims to evaluate the peristaltic movement under influence of slip boundaries characteristics, sort of concentration, heat radioactivity, flux properties, and temperature profile. Moreover, it will assess the flow dynamics with ratio of mass and heat exchange under the effect of critical parameters which include Prandtl number, Grashof number, slip limitations, and Hartmann number. So, the research will widen the theoretical underpinning of complex fluid transportation of magneto-pseudoplastic nanofluids under peristaltic flux and explicate the practical outcomes in terms of slip boundary settings in such systems. The results and conclusions are imperative for restructuring and devising biomedicine engineering, microfluidic equipment and gadgets, manufacturing techniques for complex fluid with peristaltic flow under the influence of slip limitations and magnetic force.

Influence of slip conditions and applied magnetic field on peristaltic propulsion of ellis fluid flow in a homogeneous conduit: a parametric analysis

The peristaltic mechanism has recently garnered significant attention in biological and biomedical engineering fields. This study investigates the magnetohydrodynamic (MHD) peristaltic propulsion of an Ellis fluid through a uniform channel, incorporating slip boundary conditions. Both magnetic field presence and slip effects modulate the peristaltic motion, with various factors influencing the sinusoidal waves along the channel walls. Through appropriate assumptions and simplifications, we derive governing equations for the flow and magnetic field. The resulting nonlinear system of differential equations is solved using a perturbation technique. We thoroughly examine three key metrics: velocity, pressure gradient, and streamlines. Findings indicate that magnetic field presence and slip conditions significantly impact flow behaviour. Slip coefficients positively influence velocity and pressure difference, while the magnetic field tends to decelerate the velocity profile. A comparative analysis between Newtonian and non-Newtonian models reveals notable differences in velocity profiles. These insights have potential applications across a wide spectrum of industrial and biological contexts. This study contributes to the understanding of complex fluid dynamics in peristaltic systems, offering valuable perspectives for both theoretical advancement and practical applications in biomedical and industrial fields.

H3PO4-Impregnated Covalent Organic Framework Membrane on Separators to Prevent Lithium Metal Anode Dendrite Growth.

Inhibiting the growth of lithium dendrites is crucial for battery safety. For separators, their favorable electrolyte wettability, uniform current density, and high ionic conductivity are beneficial for avoiding Li dendrite growth. In this work, we propose a separator (PA@COF/PP) by modifying a polypropylene separator with H3PO4-functionalized covalent organic frameworks. The uniform channels of the covalent organic frameworks and H3PO4 can homogenize the current and act as ionic conductors for efficient Li+ migration. The synthesized separator effectively suppresses the growth of lithium dendrites and improves the stability of the batteries. A symmetric cell with the PA@COF/PP separator exhibits a stable life span over 4000 hours at a high current density of 5 mA cm-2, compared to the commercial PP separator, which lasts only 159 hours. This work provides an efficient method and novel inspiration for the construction of dendrite-free lithium metal batteries.

Analysis of electroviscous effects in electrolyte liquid flow through a heterogeneously charged uniform microfluidic device

Charge-heterogeneity (i.e., surface charge variation in the axial direction of the device) introduces non-uniformity in flow characteristics in the microfluidic device. Thus, it can be used for controlling practical microfluidic applications, such as mixing, mass, and heat transfer processes. This study has numerically investigated the charge-heterogeneity effects in the electroviscous (EV) flow of symmetric (1:1) electrolyte liquid through a uniform slit microfluidic device. The Poisson’s, Nernst-Planck (N-P), and Navier–Stokes (N-S) equations are numerically solved using the finite element method (FEM) to obtain the flow fields, such as total electrical potential (U), excess charge (n *), induced electric field strength (E x), and pressure (P) fields for following ranges of governing parameters: inverse Debye length (2 ≤ K ≤ 20), surface charge density (4 ≤ S 1 ≤ 16), and surface charge-heterogeneity ratio (0 ≤ S rh ≤ 2). Results have shown that the total potential (∣ΔU∣) and pressure (∣ΔP∣) drop maximally increase by 99.09% (from 0.1413 to 0.2812) (at K = 20, S 1 = 4) and 12.77% (from 5.4132 to 6.1045) (at K = 2, S 1 = 8), respectively with overall charge-heterogeneity (0 ≤ S rh ≤ 2). Electroviscous correction factor (Y, i.e., ratio of effective to physical viscosity) maximally enhances by 12.77% (from 1.2040 to 1.3577) (at K = 2, S 1 = 8), 40.98% (from 1.0026 to 1.4135) (at S 1 = 16, S rh = 1.50), and 41.35% (from 1 to 1.4135) (at K = 2, S rh = 1.50), with the variation of S rh (from 0 to 2), K (from 20 to 2), and S 1 (from 0 to 16), respectively. Further, a simple pseudo-analytical model is developed to estimate the pressure drop in EV flow, accounting for the influence of charge-heterogeneity based on the Poiseuille flow in a uniform channel. This model predicts the pressure drop ± 2%–4% within the numerical results. The robustness and simplicity of this model enable the present numerical results for engineering and design aspects of microfluidic applications.

When cellulose nanocrystals meet graphene oxide: Structurally enhanced aerogels for efficient solar steam generation and water purification

Pollution, population growth, and climate change are intensifying global freshwater shortages. Traditional methods of collecting freshwater, such as rainwater harvesting and sewage treatment, have high energy consumption, limiting their implementation in underdeveloped regions. On the other hand, solar-driven seawater evaporation offers a promising solution, purifying water using naturally abundant solar energy. Reduced graphene oxide (rGO) is considered as a strong candidate for this purpose due to its broad spectral absorption. However, its hydrophobicity hinders its direct use in solar steam generators. Here, we report the preparation of a series of cellulose nanocrystal (CNC)-rGO aerogels (CGAs) through a one-pot hydrothermal gelation process, followed by unidirectional freeze-drying. The introduction of CNCs enhances the hydrophilicity and structural stability of the resulting CGAs. The CGAs also feature uniform and unidirectional channels that promote efficient water transport, as confirmed by scanning electron microscopy (SEM) and X-ray microtomography (XMT). The CGAs have an optimized water evaporation rate of 1.80 kg m−2 h−1 under 1 sun irradiation, with 90 % solar-to-vapor energy efficiency. Moreover, durability and seawater desalination tests provide additional evidence for the practicality of CGAs in water purification. It is anticipated the implementation of CGAs will expedite the application of solar steam generators in practical scenarios.

Construction of electrospun multistage ZnO@PMIA gel electrolytes for realizing high performance zinc-ion batteries

As an important component of ZIBs, flexible gel electrolytes offer the advantages of solid/liquid electrolytes and good interfacial bonding. However, limited by poor ionic conductivity and mechanical properties, traditional gel electrolytes are still unable to meet realistic applications. To solve the above problems, in this paper, poly(m-phenylene isophthalamide) (PMIA) nanofiber membranes were prepared by electrospinning, and then ordered zinc oxide (ZnO) nanorods were grown on their surfaces by hydrothermal method, and ZnO@PMIA nanofiber membranes were combined with poly(vinyl alcohol) (PVA) gel to obtain ZnO@PMIA-PVA (ZPP) composite electrolytes. On the one hand, thanks to the advantages of large specific surface area and good electrical conductivity of PMIA nanofibers and ZnO nanorods, they can provide continuous and uniform transmission channels for Zn2+ .On the other hand, ZPP combines the nanofiber layer with the gel layer, which possesses excellent mechanical properties and produces a well-bonded interface with the electrode, which can effectively reduce the internal resistance and resist the penetration of the dendrimer into the electrolyte during long cycling. The results show that the ZPP composite electrolyte has a high ionic conductivity (18.3 mS·cm-1) and exhibits obvious advantages in inhibiting hydrogen precipitation and oxidative decomposition of Zn anode, and the Zn/ZPP/Zn symmetric battery can be recycled for >1000 h at 3 mA·cm-2, and the full battery Zn/ZPP/MnO2 can still maintain 159.3 mAh·g-1 residual capacity after 1000 cycles with stable long-cycle performance and high coulombic efficiency (CE) (99 %). This flexible composite electrolyte has high safety, mechanical and electrochemical properties, which can realize high-performance ZIBs, and is expected to provide a new strategy for next-generation wearable energy storage devices.

A cationic three-dimensional covalent organic framework membrane for nanofiltration of molecules and rare Earth ions

Permanently microporous materials have evolved as focal point of research for tackling issues in separation science and membrane technology. Covalent organic frameworks (COFs) stand out for their distinctive synergy of crystalline nature, uniform channels, and structural diversities. Three-dimensional (3D) COFs, distinguished by angstrom-sized and interconnected channels, hold special promise for separating small targets; however, this potential remains underexplored. Here, we report feasible growth of cationic 3D COF membranes on a flexible polymer substrate for versatile nanofiltration toward both molecules and ions. Through comprehensive performance evaluations, we reveal that the resultant membrane exhibits durable and prominent molecular selectivity to separate fine species with molecular weights above 300 g mol−1 at fast methanol permeation. Lanthanide ions of industrial value also can be harvested by the membrane with rejection rates of up to 91.4%. Together with its nonselectivity to competing ions, our membrane implements efficient extraction of rare earth elements from ion mixtures. These findings illuminate the potential of 3D COFs for liquid separation and offer a solution to building versatile membranes.

Research on the sub-millisecond underwater electrical wire explosion process

Abstract Underwater electric wire explosion (UEWE) has great potential as a shockwave source for medical and industrial applications. This paper focuses on the process of the sub-millisecond underwater electrical wire explosion (smUEWE). The study compared the smUEWE and the microsecond underwater electrical wire explosion, which revealed the occurrence of partial vaporization under smUEWE, leading to the formation of bamboo-shaped cavities and frontal shock waves. The experiments of smUEWE were carried out under different stored energy, the results indicated the plasma shrinkage and cavity separation during the overall ionization process. Additionally, the study observed secondary breakdown caused by the uneven distribution of ionization products. An analysis was conducted on smUEWE considering partial vaporization, which divided the electrical explosion into a positive feedback process which promoted the axial instability and a negative feedback process which formed the uniform plasma channel. The analysis results was consistent with the experimental results.

Bed Roughness Incorporated Lift Force Formulation for Sediment Concentration Solutions

Within the field of sediment transport dynamics, there is an emphasis on the need for providing and improving simplified analytical solutions from which the findings can be extended upon. Typically, solutions have been developed from the understanding and incorporation of vertical velocity components/distribution; however, there remains opportunity for analytical enhancement. Under uniform open channel dilute sediment laden flow conditions, the type II concentration profile reflects the maximum concentration at a distance from the bed. To analytically depict the type II profile, it is essential to describe the vertical velocity components acting within the flow hydrodynamics. Yet, the impact of bed roughness on the vertical velocity distribution influencing a sediment particle has not been articulated. Hence, in this research, the impact of bed roughness is incorporated into the vertical velocity distribution to formulate the lift force acting upon a particle, to provide a sediment concentration solution. The proposed analytical vertical velocity distribution solution is validated against existing formulations, followed by the proposed sediment concentration being validated against existing solutions. Here, the results indicate that analytically incorporating the bed roughness alongside the secondary current induced vortices provides a lift force solution that can depict the type II concentration profile. Under relatively low shear velocity, increasing the sediment diameter allows for a clearer depiction of the near surface region and profile curvature. Furthermore, the proposed sediment concentration solution can accurately depict the near surface region, curvature of concentration, and maximum concentration under relatively large shear velocity data. Importantly, under conditions where both the shear velocity and sediment diameter are relatively large, the maximum concentration is captured with greater accuracy; however, the curvature of the profile and the near surface region accuracy are hindered. It is to be noted, that due to the formulation of the proposed velocity distribution the accuracy of the solution towards the bed decreases due to instability caused as the characteristic depth decreases to zero.

Numerical study of aphron drilling crosser fluids coating layer incorporated blood with zinc oxide (ZnO) nanoparticles injected in esophagus

AbstractThis study aims to explore a novel cross model for peristaltic flow, which has not been previously addressed. The focus is on investigating the peristaltic flow of an incompressible nanofluid within a vertically uniform channel. The current model has application in drug delivery, biomedical engineering, lab on chip etc. Utilizing peristaltic flow for drug delivery systems in symmetric channels offers precise control over fluid motion, non‐Newtonian fluids, such as polymer solutions used in drug formulations, exhibit complex flow behavior that can be manipulated through peristaltic pumping mechanisms. This application has the potential to revolutionize targeted drug delivery, enhancing therapeutic efficacy and minimizing side effects. Studying peristaltic flow in symmetric channels for non‐Newtonian fluids offers interdisciplinary insights and innovative applications. Understanding fluid rheology, channel geometry, and peristaltic pumping can lead to novel strategies for fluid control, with implications for healthcare, biotechnology, and materials science advancements. To simplify the complex system of nonlinear partial differential equations governing the flow, we consider long wavelengths and low Reynolds numbers. Subsequently, we employ Shooting methods to solve this system of equations, providing a comprehensive evaluation of the numerical results for key parameters such as velocity, temperature, concentration, and pressure gradient. The findings are presented through graphical representations of significant flow parameters.

DBMKA-Net:Dual branch multi-perception kernel adaptation for underwater image enhancement

In recent years, due to the dependence on wavelength-based light absorption and scattering, underwater photographs captured by devices often exhibit characteristics such as blurriness, faded color tones, and low contrast. To address these challenges, convolutional neural networks (CNNs) with their robust feature-capturing capabilities and adaptable structures have been employed for underwater image enhancement. However, most CNN-based studies on underwater image enhancement have not taken into account color space kernel convolution adaptability, which can significantly enhance the model’s expressive capacity. Building upon current academic research on adjusting the color space size for each perceptual field, this paper introduces a Double-Branch Multi-Perception Kernel Adaptive (DBMKA) model. A DBMKA module is constructed through two perceptual branches that adapt the kernels: channel features and local image entropy. Additionally, considering the pronounced attenuation of the red channel in underwater images, a Dependency-Capturing Feature Jump Connection module (DCFJC) has been designed to capture the red channel’s dependence on the blue and green channels for compensation. Its skip mechanism effectively preserves color contextual information. To better utilize the extracted features for enhancing underwater images, a Cross-Level Attention Feature Fusion (CLAFF) module has been designed. With the Double-Branch Multi-Perception Kernel Adaptive model, Dependency-Capturing Skip Connection module, and Cross-Level Adaptive Feature Fusion module, this network can effectively enhance various types of underwater images. Qualitative and quantitative evaluations were conducted on the UIEB and EUVP datasets. In the color correction comparison experiments, our method demonstrated a more uniform red channel distribution across all gray levels, maintaining color consistency and naturalness. Regarding image information entropy (IIE) and average gradient (AG), the data confirmed our method’s superiority in preserving image details. Furthermore, our proposed method showed performance improvements exceeding 10% on other metrics like MSE and UCIQE, further validating its effectiveness and accuracy.

Constructing high-performance micro fuel electrodes for reversible proton ceramic electrochemical cells

Reversible proton ceramic electrochemical cells (R-PCECs) are of great interest as efficient energy conversion device. Optimization of structural design can enhance the mechanical properties and gas transport of the cells, resulting in improved electrochemical performance. In this study, we developed a 7-channel micro-monolithic R-PCEC for the first time, with uniform channel distribution and smaller gas diffusion pathway length using phase inversion/extrusion technique. The assembled cell with Ni-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (Ni-BZCYYb, fuel electrode support) | BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb, electrolyte) | PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF, air electrode) structure showed a peak power density of 0.94 W cm−2 at 700 °C in fuel cell mode and electrolysis current density of 2.17 A cm−2 at 700 °C with an operating voltage of 1.3 V. Additionally, electrochemical impedance spectroscopy (EIS) further indicated that the diffusive polarization of the structured cell was effectively reduced compared to single-channel counterpart.

Właściwości i zastosowanie gruzińskiego naturalnego filipsytu

Oceanic and terrestrial sedimentary phillipsites make up very large reserves, but the use of this natural zeolite is not so wide comparing to clinoptilolite, and purpose of our study was to characterize the phillipsites of the Georgian deposits and highlight their possible application. It is shown that natural phillipsite can be used as a raw material for the synthesis of phase-pure zeolite NaX with Si/Al~1.5-1.7 in the form of octahedral crystallites with uniform micrometric (2-7 μm) dimensions, characterized by high specific surface area (590-770 m2/g) and volume of pores (0.58 cm3/g) including uniform zeolitic micropores and channels with an average diameter of 55 nm, which opens up the prospect of its use in catalysis. It has been established that natural phillipsite is a suitable carrier of bioactive metals: silver-, copper-, and zinc-containing micro-mesoporous materials have been prepared using ion-exchange reactions between zeolite and a salt of a transition metal; the products contain up to 235 mg/g of silver, 85 mg/g of copper, and 87 mg/g of zinc, and in the Kirby-Bauer disk-diffusion test show strong bacteriostatic activity against such microorganisms as gram-negative bacterium Escherichia coli, gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, fungal pathogenic yeast Candida albicans and a fungus Aspergilus niger. The use of bactericidal materials obtained on the basis of natural phillipsite is possible both for water purification and disinfection, and as fillers in the production of polymeric materials, paper and cardboard.

Polymeric Microneedles Enhance Transdermal Delivery of Therapeutics.

This research presents the efficacy of polymeric microneedles in improving the transdermal permeation of methotrexate across human skin. These microneedles were fabricated from PLGA Expansorb® 50-2A and 50-8A and subjected to comprehensive characterization via scanning electron microscopy, Fourier-transform infrared spectroscopy, and mechanical analysis. We developed and assessed a methotrexate hydrogel for physicochemical and rheological properties. Dye binding, histological examinations, and assessments of skin integrity demonstrated the effective microporation of the skin by PLGA microneedles. We measured the dimensions of microchannels in the skin using scanning electron microscopy, pore uniformity analysis, and confocal microscopy. The skin permeation and disposition of methotrexate were researched in vitro. PLGA 50-8A microneedles appeared significantly longer, sharper, and more mechanically uniform than PLGA 50-2A needles. PLGA 50-8A needles generated substantially more microchannels, as well as deeper, larger, and more uniform channels in the skin than PLGA 50-2A needles. Microneedle insertion substantially reduced skin electrical resistance, accompanied by an elevation in transepidermal water loss values. PLGA 50-8A microneedle treatment provided a significantly higher cumulative delivery, flux, diffusion coefficient, permeability coefficient, and predicted steady-state plasma concentration; however, there was a shorter lag time than for PLGA 50-2A needles, base-treated, and untreated groups (p < 0.05). Conclusively, skin microporation using polymeric microneedles significantly improved the transdermal delivery of methotrexate.

Optimal Guard Channel Reservation and its Comparison with Fractional Channel Policies in Mobile Cellular Network

In the current communication era, 2G voice services coexist with higher generation mobile network voice services like Voice over Long Term Evolution (VoLTE) in 4G and Voice over New Radio (VoNR) in 5G. Subscribers registered in the 5G network, but their voice option is in 4G so voice calls can be handled through the Evolved Packet System (EPS) Fallback or Radio access technology (RAT) Fallback. Similarly, subscribers register in a 4G network, but their voice option is in 3G or 2G so voice calls can be handled through Circuit Switched Fallback (CSFB). To provide uninterrupted voice service in such wireless networks usually handoff calls (HCs) receive higher priority than new calls (NCs). So, some guard radio resources (i.e., channels in 2G or RBs in 4G or 5G) may be reserved in each cell to handle this type of HCs. If more channels are reserved for HCs, then the handoff call-dropping probability (HCDP) will be decreased and at that time the new call-blocking probability (NCBP) will be increased. So, by considering the target HCDP if channels are reserved for HC, then HCDP will remain below the target and NCBP will be minimum. In this paper first, we proposed an optimal channel reservation (OCR) policy that reserves guard channels according to the given target HCDP. Second, we compared our OCR policy with fractional channel (FC), limited fractional channel (LFC), and uniform fractional channel (UFC) policies. Finally, we observed the performance of all these policies considering the Global System for the Mobile Communication (GSM) network.

GaSb/Si Heterojunction Based Pocket Engineered Vertical Non-Uniform Channel Double Gate TFETs for Low Power Applications

This article compares the performance of two Vertical Non-Uniform Channel Double Gate Tunnel Field Effect Transistors (VNUCDGTFETs), a normal all-Silicon Tunnel Field-Effect Transistor (TFET) having a pocket and another one a Gallium Antimonide/Silicon heterojunction TFET with pocket. GaSb is a III-V narrow energy band gap material, employed in the source area of the TFET structure to decrease the tunneling width and thus to make more number of carriers capable enough to tunnel through the heterojunction. The proposed source pocket heterojunction non uniform channel TFET presents superior performance as compared to the conventional non uniform channel vertical TFET with a pocket, regarding a larger ION/IOFF ratio, a reduced sub-threshold swing, and a smaller threshold voltage at VDS = 0.5 V. Furthermore, the proposed TFET device undergoes a comprehensive analysis of both DC parameters and various analog/RF parameters.