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This study investigates the impact of cooling rate and alloy composition on phase formations and properties of (CoCrCuTi)100−xFex (x = 0, 5, 10, 12.5, 15) high-entropy alloys (HEAs). Samples were synthesized using arc-melting and electromagnetic levitation, followed by quenching through the use of a Cu chill or V-shaped Cu mold. Cooling rates were evaluated by measuring dendrite arm spacings (DASs), employing the relation DAS = k ɛ−n, where constants k = 16 and n = ½. Without Fe addition, a microstructure consisting of BCC1 + BCC2 phases formed, along with an interdendritic (ID) FCC Cu-rich phase. However, with the addition of 5–10% Fe, a Cu-lean C14 Laves phase emerged, accompanied by a Cu-rich ID FCC phase. For cooling rates below 75 K/s, alloys containing 10% Fe exhibited liquid phase separation (LPS), characterized by globular Cu-rich structures within the Cu-lean liquid. In contrast, for the same composition, higher cooling rates of 400–700 K/s promoted a dendritic/interdendritic microstructure. Alloys with 12.5–15 at. % Fe displayed LPS irrespective of the cooling rate, although an increase in uniformity was noted at rates exceeding 700 K/s. Vickers hardness and fracture toughness generally increased with Fe content, with hardness ranging from 444 to 891 HV. The highest fracture toughness (5.5 ± 0.4 KIC) and hardness (891 ± 66 HV) were achieved in samples containing 15 at. % Fe, cooled at rates of 25–75 K/s. [ABSTRACT FROM AUTHOR]

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd 0.4 Co 0.6 Dy X Ce X Fe 2-2X O 4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs. [Display omitted] [ABSTRACT FROM AUTHOR]

Process parameter optimization and selection play a crucial role in additive manufacturing, particularly in determining the quality and characteristics of the final product. Among these parameters, the infill pattern holds significant importance as it directly influences the structural integrity, production time, and material usage efficiency of the printed object. This research focuses on identifying the most suitable 3D printing infill pattern process parameters for thermoplastic polyurethane (TPU) material, specifically for applications in pipeline construction. The criteria considered for process parameter selection include printing time, ultimate tensile strength, ultimate flexural strength, and surface defect minimization. Various infill patterns, including hexagonal, line, solid, triangle (35°), triangle (55°), and line patterns, are evaluated as alternatives. Utilizing the multi‐criteria decision‐making technique known as analytical hierarchy process (AHP), a systematic approach is employed to determine the optimal printing pattern. The findings of this study reveal that the hexagonal infill pattern outperforms other selected patterns in terms of meeting the criteria set forth for pipeline construction using TPU material. This research contributes to enhancing the efficiency and quality of additive manufacturing processes in pipeline applications, emphasizing the importance of informed parameter selection for achieving desired performance outcomes. [ABSTRACT FROM AUTHOR]

To improve the energy absorption characteristics of thin-walled structures under oblique loads, a new hexagon hierarchical gradient structure (HHGS) was designed in this work, which was inspired by the fractal structure of tree gradient in nature. The crashworthiness of the structure under oblique loads was systematically studied by numerical simulation method. The force-displacement curve of this structure under oblique loads is different from that of conventional thin-walled tubes under axial loads. Crashworthiness comparisons show that gradient structure can significantly reduce initial peak forces and maintain good deformation patterns and energy absorption advantages compared to other structures under oblique loads, at 15° load, the specific energy absorption of the third-order structure was increased by 59.20% at the highest level, at the same time, the initial peak force was reduced by 94.23%. At 30° load, the specific energy absorption of the third-order structure was increased by 32.30% and the initial peak force was reduced by 84.45%. [ABSTRACT FROM AUTHOR]

A compact, low-profile, and ultra-wideband antenna is always desirable for airborne Unmanned Aerial Vehicles (UAV) applications. In this paper, an ultra-wideband monopole antenna is presented with the benefit of a compact and low-profile design structure. The antenna design enables efficient communication without interfering with the UAV's other components. The antenna is designed using a slotted-hexagonal-patch fed from a co-planar microstrip feed. The bow-tie-shaped slot along with a few other rectangular-shaped parasitic slots are loaded in the hexagonal patch for bandwidth enhancement. The coplanar feed with top ground offers minimum interference with the UAV structure. The non-conducting bottom plane allows seamless integration without causing any interference to the antenna. An equivalent circuit model (ECM) of the proposed antenna is also developed. The antenna structure is fabricated and the measured results are validated. A good agreement between the measured and simulated results is observed. The antenna covers an ultra-wideband ranging from 3 GHz to 13.5 GHz with a maximum gain of 4.0dBi. The size of the antenna is 0.24λ0 ×0.29λ0 ×0.01λ0. The developed antenna, therefore, demonstrates that it is a strong contender for ultra-wideband UAV-based applications. [ABSTRACT FROM AUTHOR]

This study delves into the microwave dielectric properties of Li2Y9(SiO4)6O2F ceramics, synthesized using the conventional solid-state method. By employing x-ray diffraction analysis and meticulous data refinement across various temperatures, we unequivocally confirm the hexagonal crystal structure of Li2Y9(SiO4)6O2F ceramics. The refined lattice parameters, observed at a sintering temperature of 1275°C, exhibit a = b = 9.33318 Å, c = 6.71725 Å, with a corresponding unit cell volume of V = 506.73529 Å3. In-depth scrutiny of the microstructure of the ceramics' grains using scanning electron microscopy (SEM) reveals an optimal relative density of 96.2%. Subsequently, the study explores the impact of porosity, packing fraction, relative density, and Si-O bond valence (VSi-O) on the microwave dielectric properties of Li2Y9(SiO4)6O2F ceramics. Notably, the Li2Y9(SiO4)6O2F ceramic sintered at 1275°C demonstrates superior performance metrics, boasting an εr value of 14.28, a Q × f product of 16,760 GHz (at f = 9.4 GHz), and a temperature coefficient of frequency (τf) at 3.14 ppm/°C. This comprehensive investigation contributes valuable insights into optimizing the microwave dielectric characteristics of Li2Y9(SiO4)6O2F ceramics for potential applications in advanced electronic devices. [ABSTRACT FROM AUTHOR]

Preparation of Co3O4 nanoparticles (NPs) via a chemical reduction method at room temperature in a lyotropic liquid crystal (LLC) medium is described. A mixture of triton X-100 and water in the ratio 2.1:2.9 (wt%) exhibited LLC having a hexagonal structure in the temperature range of 25–29 °C. The NPs were prepared in this medium by reducing cobalt(II) chloride hexahydrate (CoCl2·6H2O) using sodium borohydride (NaBH4) resulting in nearly spherical particles having a size of ∼ 100 nm. The LLC medium facilitated a controlled growth of the NPs and also provided stabilization for the NPs by preventing their aggregation. The anti-bacterial activity of the particles indicated a significant activity towards gram-negative bacteria. Anticancer activity against breast cancer cell line MCF-7 showed an impressive IC50 value of 30.8 µg/mL. Additionally, the efficiency of the Co3O4 NPs as catalyst for the reduction of 4-nitrophenol and degradation of a dye named methylene blue was evaluated; the apparent rate constant values calculated for these reactions were 1.8 × 10−2 min−1 and 3.1 × 10−2 min−1 respectively. Besides, particles displayed efficient activity till 5th cycle. [ABSTRACT FROM AUTHOR]

The present study conducted a successful green synthesis of zinc oxide nanoparticles (ZnO NPs) from the aqueous solution of Salvadora persica leaf extract as capping agent and used for methyl orange dye removal. The morphology, chemical composition, crystallinity, optical property and isothermal behavior of synthesized nanoparticles were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Fourier transform infra-red (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy (UV-Vis). The influencing factors on MO removal such as preparation method, dose, pH, contact time, and dye concentration were examined. The UV-Vis absorption band was found at 365 nm and the XRD analysis confirmed the crystallinity of the ZnO NP and the particle sizes were in the range of 32-68 nm. The FTIR bands confirm the presence of bioactive compounds. SEM images showed the formation of hexagonal and rod-shaped nanoparticles. The results revealed that a maximum methyl orange removal of 68% was obtained with an amount of 0.05 g of ZnO NPs at pH 5. The adsorption process can be well explained by the Langmuir isotherm model. This research demonstrates a green method of preparing various ZnO nanoparticle with a remarkable efficiency towards the removal of methyl orange dye. HIGHLIGHT This study describes, for the first time, a facile green approach for the synthesis of ZnO nanoparticles using an aqueous leaf extract of Salvadora persica for methyl orange removal.;

Hexagonal TiO2/SiO2 Porous Microplates have been successfully synthesized by incorporation of Ti precursors into SiO2 synthesized from Si precursors in a gelatin-CTAB mixture via the hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX, nitrogen adsorption-desorption and Fourier transform infrared spectroscopy (FTIR). The sample has a surface area of 735 m2/g, pore volume of 0.67 cc/g, and pore diameter of 3.2 nm, according to the results of the characterization of hexagonal TiO2/SiO2 porous microplates. The transformation of SiO2 microspheres into hexagonal TiO2/SiO2 porous microplates is revealed by a microparticle size increase of 84% and the transition of Si−O bonds into Ti−O and Si−O as measured by FTIR. The photocatalytic activity of hexagonal TiO2/SiO2 porous microplates resulted in 81.15% photodegradation of methylene blue under UV light irradiation within 60 min, which was 21 % better than SiO2. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

ZnO and Zn(0.97-x)Al0.03MnxO (x = 0.00 (AlMnZ0), 0.04 (AlMnZ4), 0.05 (AlMnZ5) and 0.06 (AlMnZ6)) nanopowders that have been synthesized in powder form by using coprecipitation method at powder-based low temperature are zinc chloride (Sigma Aldrich), manganese (II) chloride tetrahydrate (Sigma Aldrich), and aluminum chloride hexahydrate (Sigma Aldrich). The powder of zinc chloride, aluminum chloride hexahydrate and manganese (II) chloride are dissolved in 0.5 M HCl, then a precipitating agent is added in the form of NaOH 5 M base into the solution by slowly dropping NaOH 5 M solution into the precursor until a pH of 10 is reached which causes the clear and transparent solution turns into milky white. In order for the reaction to run perfectly, the stirring process is carried out in a hot plate stirrer for 90 minutes at a temperature of 85 °C. After the solution is formed, it is washed with distilled water repeatedly until there is no impurities and it is filtered with filter paper to separate the precipitate from the solution. X-ray Diffraction (XRD) and Ultra Violet Visible (UV-VIS) Spectroscopy have been used to characterize ZnO nanopowder products through (Al+Mn) doping. The results show that AlMnZ0, AlMnZ4, AlMnz5 and AlMnZ6 nanopowder has the form of a hexagonal wurtzite crystal phase with a crystal size of ~38.03881-47.57561 nm. The optical band gap of ZnO nanopowder can be increased by atomic doping (Al+Mn). The increase in the optical band gap of AlMnZ0, AlMnZ4, AlMnZ5 and AlMnZ6 nanopowder is related to the Burstein-Moss effect, that is when (Al+Mn) atoms are successfully incorporated into ZnO nanopowders, there is a vacancy of the oxygen atom in the host crystal. [ABSTRACT FROM AUTHOR]

Hexagonal TiO2/SiO2 Porous Microplates have been successfully synthesized by incorporation of Ti precursors into SiO2 synthesized from Si precursors in a gelatin-CTAB mixture via the hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX, nitrogen adsorption-desorption and Fourier transform infrared spectroscopy (FTIR). The sample has a surface area of 735 m²/g, pore volume of 0.67 cc/g, and pore diameter of 3.2 nm, according to the results of the characterization of hexagonal TiO2/SiO2 porous microplates. The transformation of SiO2 microspheres into hexagonal TiO2/SiO2 porous microplates is revealed by a microparticle size increase of 84% and the transition of Si-O bonds into Ti-O and Si-O as measured by FTIR. The photocatalytic activity of hexagonal TiO2/SiO2 porous microplates resulted in 81.15% photodegradation of methylene blue under UV light irradiation within 60 min, which was 21% better than SiO2. [ABSTRACT FROM AUTHOR]

High-throughput ab initio calculations were employed to study the lattice reorientation process accompanying twinning under plastic deformation in hexagonal metals, as well as in alloyed Mg and Ti. The results indicate that, in unalloyed hexagonal metals, reorientation consumes the highest and lowest energies in Be and Mg, respectively, with intermediate energies in Sc, Co, Ti, Zr and Dy. The shuffle component always contributes a significant part of the reorientation energy in Mg, whereas in Ti with sufficient shear strain, subsequent reorientation process becomes energy downhill. In alloyed Mg and Ti, appropriate alloying significantly reduces the reorientation energy, and especially in alloyed Ti, there is significant negative correlation between the reorientation energy and certain properties of the alloying elements. The results are consistent with the fact that reorientation has been experimentally observed in compressed Mg nanopillars, but only in atomic scale simulations under high strain rate in Ti.

This study investigates the impact of cooling rate and alloy composition on phase formations and properties of (CoCrCuTi)100−xFex (x = 0, 5, 10, 12.5, 15) high-entropy alloys (HEAs). Samples were synthesized using arc-melting and electromagnetic levitation, followed by quenching through the use of a Cu chill or V-shaped Cu mold. Cooling rates were evaluated by measuring dendrite arm spacings (DASs), employing the relation DAS = k ɛ−n, where constants k = 16 and n = ½. Without Fe addition, a microstructure consisting of BCC1 + BCC2 phases formed, along with an interdendritic (ID) FCC Cu-rich phase. However, with the addition of 5–10% Fe, a Cu-lean C14 Laves phase emerged, accompanied by a Cu-rich ID FCC phase. For cooling rates below 75 K/s, alloys containing 10% Fe exhibited liquid phase separation (LPS), characterized by globular Cu-rich structures within the Cu-lean liquid. In contrast, for the same composition, higher cooling rates of 400–700 K/s promoted a dendritic/interdendritic microstructure. Alloys with 12.5–15 at. % Fe displayed LPS irrespective of the cooling rate, although an increase in uniformity was noted at rates exceeding 700 K/s. Vickers hardness and fracture toughness generally increased with Fe content, with hardness ranging from 444 to 891 HV. The highest fracture toughness (5.5 ± 0.4 KIC) and hardness (891 ± 66 HV) were achieved in samples containing 15 at. % Fe, cooled at rates of 25–75 K/s.

The proposed hexagonal shaped antenna is designed to possess circularly polarized triple resonating band operation using a novel technique of paired open-ended slot embedded around antenna axis. The open-ended slots cut at and along either side of horizontal axis of the hexagonal radiating patch create meandered electrical path which allows the current circulation at the center of patch to degenerate the two orthogonal modes for circular polarization (CP) radiation. Hexagonal antenna fed with CPW feed give rise wide impedance bandwidth and wide axial ratio bandwidth. Circular polarization purity is achieved by optimizing the length of paired open-ended slots. A rectangular tunable notch embedded in the ground plane controls the impedance bandwidth by limiting its upper edge frequency. The proposed antenna possesses a wide impedance bandwidth of 68.4%, axial ratio bandwidth (ARBW) of 57.14% and peak gain of 4 dB. The proposed circularly polarized antenna holds triple circularly polarized bands resonating at 1.52 GHz, 1.73 GHz and 3.78 GHz with axial ratio bandwidth (ARBW) of 15 MHz, 15 MHz and 2720 MHz respectively, which is about 0.98%, 0.98% and 57.14% with respect to center resonating frequency. Antenna reports peak gain of 4 dB. The magnitude of axial ratio near to 0dB for all bands indicates purity in CP. [ABSTRACT FROM AUTHOR]

This manuscript introduces an innovative six-way power divider design using substrate integrated waveguide technology, specifically tailored for applications in both X-band and Cband frequencies. The utilization of SIW technology in this design offers significant advantages, including exceptional isolation between output ports, and a high level of return loss. Additionally, the design incorporates a coaxial port at its center, facilitating the analysis of the power divider's performance. This coaxial port can also serve as a feeding structure for an antenna array, adding to its versatility. The simulation results indicate that the input return loss for port 1 of the power divider exceeds 23dB, demonstrating excellent performance. Furthermore, the design has been successfully fabricated, and the measured results align with the expected performance standards, affirming its practicality and functionality. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Luminescence properties for a series of fluoroperovskite compounds have been studied in details. Among these, some compounds like KMgF3, NaMgF3 and LiBaF3 are easily prepared by wet-chemical synthesis and have been already reported in previous publications. Whereas compounds, specially containing 'Ca' ions such as KCaF3, CsCaF3 and RbCaF3 appears impossible to form through precipitation. Hence, attempts were made to prepare remaining compounds via old conventional solid-state route. Present study focuses more on the difficulties and challenges came across during the synthesis of these fluoride phosphors. Also, it was found that CsCaF3 and RbCaF3 exists as cubic, whereas KCaF3 and RbMgF3 are stable in orthorhombic and hexagonal phases, respectively, which are in accordance with their calculated tolerance 't' factors. Photoluminscence (PL), Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) studies on some of these europium-activated fluoroperovskite complexes, synthesized successfully by solid-state method have also been reported in this work. [ABSTRACT FROM AUTHOR]

A 314-type MAB phase V3PB4 with hexagonal crystal structure is synthesized by self-propagating high temperature combustion synthesis (SHS), with the help of the full first-principles predictions for the phase stability and adiabatic combustion temperature of SHS. Using XRD and TEM, V3PB4 crystallizes in the space group of P6¯m2, with the lattice parameters a = 3.030 Å and c = 9.148 Å, of much interest, well with the predicted one. Furthermore, the electronic structure, chemical bonding, and elastic properties of hex-V3PB4 are predicted by first-principles. No bandgap around Fermi energy indicates its electronic conductor. And the strong covalent bonding is present between the B and V atoms with, significantly, much weaker V-P bond. With the help of the theoretical model of bond stiffness, the significantly high ratio of bond stiffness of weakest bonds to the strongest ones (0.873) of hex-V3PB4 indicates its poor damage tolerance and fracture toughness. The high bond stiffness results in its high moduli in comparison with other MAB phases. As the number of inserted P atoms increases, the engineering elastic modulus decrease, without the price of an increase in density.

The study has outlined various photonic crystal fibers (PCFs) configurations for the key solution to the optimization of data rates transmission. The proposed fibers that are namely octagonal photonic crystal fiber (OPCF), hexagonal photonic crystal fiber (HPCF), and elliptical photonic crystal fiber (E-PCF) are used in the system. The dispersion parameter coefficient, pulse broadening variations, and data rates transmission are examined for proposed fibers under the same fiber lengths and number of quantization level with using pulse code modulation (PCM). The system performance is enhanced with OPCF with reducing dispersion factor, pulse broadening effects and consequently increasing data rates transmission. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biomass briquette stove is a cooking tool that is still widely used by the people of the interior of South Sulawesi. Even in urban areas, it is not uncommon to find their use because of the ease of obtaining briquettes and its relatively good efficiency. This study aims to determine the best performance of a biomass stove from three types of clay material stove shapes in different configurations of geothermal variations. The three variations of the geometric shape of the stove are cylindrical, rectangular and hexagonal using biomass material from coconut shell charcoal in the shape of a honeycomb with an inner diameter of 15 mm and an outer diameter of 65 mm and a height of 45 mm. The uniqueness of this stove is the addition of a sleeve diameter of 180mm in the stove's combustion chamber as heat insulation so that the combustion process in the combustion chamber can be more perfect. The test results show that the presence of a flat surface on the stove wall will accelerate heat loss compared to the cylindrical surface. This is in line with the results which show that the highest rate of heat loss occurs in a rectangular shape, then a six-square shape, and the last is a cylindrical shape. Furthermore, it can be concluded that the cylindrical stove is the superior of the two in terms of flame temperature, ability to boil water and thermal efficiency of 798°C, 30 liters and 73.66%, respectively.

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this work is to explore the thermal performance of a tracked tubular solar still (TSS) with a parabolic trough concentrator in Baghdad (33.27° N, 44.37° E) in September 2022. The present tubular still is distinguished by its hexagonal glass cover. The effect of integrating the TSS with a heat pipe, the still tilt angle (10°, 15°), and the depth of saline water inside the still partitions on the productivity of freshwater are investigated. The results showed that using heat pipe enhances the freshwater productivity by 25%–40% and the efficiency by 25%. For the still integrated with heat pipe, as the water depth is increased from 5.5 to 6.5 cm the productivity of freshwater is increased by 16% and 20% for tilt angles 10° and 15°, respectively. [ABSTRACT FROM AUTHOR]

This study discusses the design and manufacture of microstrip antennas that aim to widen the bandwidth in the application of Wi-Fi in the form of a hexagonal patch composed of a 2x4 element array. Microstrip antennas have a weakness, namely narrow bandwidth, therefore a modification is needed using the DGS (Defected Ground Structure) method in the form of a dumbbell circle head. The allocation of the Wi-Fi working frequency that is often used in the community is 2.4 GHz in accordance with the IEEE 802.11 protocol standard. This study discusses the result and the effect of the performance of an 2x4-element microstrip array antenna using DGS. This DGS is placed on the ground plane and uses a PCB with an epoxy fiberglass substrate material which has a dielectric constant of 4.58. The result of this research is an external device, namely a microstrip antenna that can increase data transfer capacity and work on a Wi-Fi frequency of 2.4 GHz. This research is in accordance with the antenna test parameters, which have a return loss value of -22.7 dB and VSWR 1.15. 1. The results of testing the bandwidth of the hexagonal 2x4 element microstrip patch antenna with a defected ground structure of 34 MHz. The radiation pattern of the hexagonal 2x4 element microstrip patch antenna using DGS is directional. The results of the power level implementation of a hexagonal microstrip patch antenna arranged in a 2x4 array using a DGS dBm can increase power level by 7 dBm.

Transposition flaps are some of the most commonly used flaps for reconstructing scalp defects. Limberg first described his rhomboid transposition flap in 1946. Dufourmentel flap was an improved version of the Limberg flap published in 1962 in which the base of the flap is widened to improve vascularisation. Transposition flaps are one of the best known and most widely used transposition flaps in reconstructive surgery. They have proven successful in different types of reconstructive and aesthetic situations as a full‐thickness random transposition flap. Combination of three Dufourmentel flaps to reconstruct hexagonal defects has not been reported in the literature. It is a modification of the triple Limberg flap, in which, after removing a hexagonal defect, we reconstruct the primary defect with a triple Dufourmentel flap. This flap is very useful for reconstructing large scalp defects as it provides a large amount of skin tissue with high viability; however, given its versatility, it could be used in other anatomical areas. Ann Med Surg (Lond) 2021 7:102544; Plast Reconstr Surg 2015 136:163–164; Atlas Oral Maxillofac Surg Clin North Am 2020 28:17–22. [ABSTRACT FROM AUTHOR]

This paper proposes a hexagonal meander-shaped wideband electronically reconfigurable transmitarray (HMRTA) at Ku band for satellite communications and radar applications. The proposed transmitarray offers high gain, low profile, and wideband characteristics with beam-scanning and beam-forming features. The cascaded structure is a low-profile and compact transmitarray. The transmitter (Tx) layer has an angular hexagonal patch with a meandered shape and resonating parasitic patches to enhance the bandwidth. The receiver (Rx) layer comprises a two-part hexagonal receiver patch and a dual ring impedance-matching receiver layer. The current reversal phenomena have executed the 180° phase shift by integrating two diodes in opposite directions. The measured results of a unit cell achieve a minimum insertion loss of 0.86 dB and 0.92 dB for state I and state II. The maximum insertion loss is 2.58 dB from 14.12 GHz to 18.02 GHz and is about 24.83% at 16.5 GHz. The full-wave simulations of a 20 × 20 space-fed reconfigurable transmitarray were performed. Good radiation patterns at all scanning angles of two principal planes are achieved, and the cross-polarization level remains less than −20 dB. The simulated 3 dB gain fluctuation bandwidth of the array is 15.85~18.35 GHz, and the wideband characteristics are verified. The simulation results show that the array can perform beam scanning ±60° in the elevation (y-z) plane and obtain the beam-scanning characteristics for ±60° in the Azimuth (x-z) plane. [ABSTRACT FROM AUTHOR]

Hydroquinone (HQ) was electrochemically measured using convolutive cyclic voltammetry and differential pulse voltammetry (DPV) on a nano-architecture mesoporous platinum film electrochemically grown from a hexagonal liquid crystalline template of C16EO8 surfactant in 1.0 mol/l HClO4. The HQ cyclic voltammograms produced one oxidative peak in the forward sweep of potential and one reductive peak in the reverse sweep. The effect of HQ concentration was investigated using the different electrochemical methods mentioned above. The modified platinum electrode exhibits good sensitivity for the determination of the HQ compound in 1.0 mol/l HClO4. The best executive was found for the i-t curve method developed from cyclic voltammetry of HQ. It exhibits a linear peak current response over the concentration range of 8 to 55 µmol/l, with a detection limit of 0.5726 µmol/l and a quantification limit of 1.9088 µmol/l, confirming the accuracy and sensitivity of this quick, cheap, and easy method.

A metamaterial is any material engineered with a property not discovered in naturally occurring materials. Its existence is important in the development and application of modern technology in this century. Furthermore, Its characteristics such as high sensitivity and gain can be potentially applied in antenna technology. In this research, the metamaterial implementation was used to improve low-profile microstrip antennas as ultra-wideband (UWB) applications. The proposed metamaterial consists of variations of one to four hexagonal shape split ring resonator (SRR-H) elements. This study was carried out through simulation and experiments which were operated in the frequency range 0.05–9 GHz. Based on the results, the proposed antenna with the variation of the SRR-H elements provides increased performance than the without SRR-H. The highest double-negative (DNG) metamaterial characteristic of the SRR-H four-element structure provides the highest antenna performance compared to others. The given working frequency occurs at 5.98 GHz with an increase in bandwidth of 47.49% from without SRR-H. The antenna metamaterial structure also responds by providing an ultimate gain radiation pattern of 5.97 dBi at a 45-degree angle in the Quadrant II region. Thus, the performance of the proposed antenna shows the potential for use in UWB technology.

Fins are utilized in a variety of technical applications such as heat exchangers, electrical transformers, semiconductors, air-cooled engines, gas turbines, automotive radiators, hydrogen fuel cells, and so on. Nanofluids are innovative designed fluids with improved thermal conductivity as comparison to standard coolants. The nanofluids are more efficient and well repudiated in heat transportation evaluated to regular fluids due of nanoparticle presence in the base medium. The thermal efficiency of nanofluid is more efficient due to presence of nanoparticles. With this motivation, the objective of present article is to analyze the hydrothermal analysis of MgO−water nanofluid flow across a hexagonal cavity and inner circular cylinder. The inside cylinder is fitted with various rectangular fins. The upper and bottom wall of cavity is heated while other alls cold. The dimensional equations are transmuted into non-dimensional equations system by using suitable similarity alternation. The non-dimensional system of equations is tackled by utilizing Galerkin finite element method in computational COMSOL Multiphysics software. Different streamlines isotherms and Nusselt number profile plots are designed for significance of Rayleigh number (Ra), Hartmann number (Ha) and nanoparticle volume fraction (Φ) with different fins length in the flow. From the results, it is observed that convection, velocity and heat outcomes are boosted up for the Rayleigh number. The velocity components are reduces via increment in Hartmann number and nanoparticles concentration. Furthermore, analysis reveals reduced local Nusselt number outcomes are reduced for Hartmann number while inverse trend is noted for Rayleigh number and nanoparticle volume fraction.