Search Results (168)

Diamond, renowned for its exceptional electrical, physical, and chemical properties, including ultra-wide bandgap, superior hardness, high thermal conductivity, and unparalleled stability, serves as an ideal candidate for next-generation high-power and high-temperature electronic devices. Among diamond-based devices, Schottky barrier diodes (SBDs) have garnered significant attention due to their simple architecture and superior rectifying characteristics. This review systematically summarizes recent advances in diamond SBDs, focusing on both metal–semiconductor (MS) and metal–interlayer–semiconductor (MIS) configurations. For MS structures, we critically analyze the roles of single-layer metals (including noble metals, transition metals, and other metals) and multilayer metals in modulating Schottky barrier height (SBH) and enhancing thermal stability. However, the presence of interface-related issues such as high densities of surface states and Fermi level pinning often leads to poor control of the SBH, limiting device performance and reliability. To address these challenges and achieve high-quality metal/diamond interfaces, researchers have proposed various interface engineering strategies. In particular, the introduction of interfacial layers in MIS structures has emerged as a promising approach. For MIS architectures, functional interlayers—including high-k materials (Al₂O₃, HfO₂, SnO₂) and low-work-function materials (LaB₆, CeB₆)—are evaluated for their efficacy in interface passivation, barrier modulation, and electric field control. Terminal engineering strategies, such as field-plate designs and surface termination treatments, are also highlighted for their role in improving breakdown voltage. Furthermore, we emphasize the limitations in current parameter extraction from current–voltage (I–V) properties and call for a unified new method to accurately determine SBH. This comprehensive analysis provides critical insights into interface engineering strategies and evaluation protocols for high-performance diamond SBDs, paving the way for their reliable deployment in extreme conditions. Full article

Vertical GaN P-i-N diodes exhibit excellent high-voltage performance, fast switching speed, and low conduction losses, making them highly attractive for power applications. However, their breakdown voltage is severely constrained by electric field crowding at device edges. Using silvaco tcad (2019) tools, this work systematically evaluates multiple edge termination techniques, including deep-etched mesa, beveled mesa, and field-plate configurations with both vertical and inclined mesa structures. We present an optimized multi-drift-layer GaN P-i-N diode incorporating field-plate termination and analyze its electrical performance in detail. This study covers forward conduction characteristics including on-state voltage, on-resistance, and their temperature dependence, reverse breakdown behavior examining voltage capability and electric field distribution under different temperatures, and switching performance addressing both forward recovery phenomena, i.e., voltage overshoot and carrier injection dynamics, and reverse recovery characteristics including peak current and recovery time. The comprehensive analysis offers practical design guidelines for developing high-performance GaN power devices. Full article

Friction stir welding (FSW) is a novel welding technique that produces a solid-state weld by generating frictional heat and plastic deformation at the weld spot with a revolving, non-consumable welding tool. Despite processing a wide range of industrial materials, FSW has concentrated on welding aluminum and its alloys because of its high strength-to-weight ratio and uses in the shipbuilding, aerospace, and other fabrication industries. Important FSW process factors that determine the mechanical qualities of the weldment are the tool tilt angle, tool traverse feed, tool pin profile, tool rotational speed (TRS), tool traverse speed (TTS), tool pin profile (TPP), and shoulder plunge depth. Variations in the required process parameters cause defects, which lower the weld quality of FSWed aluminum alloys (AA). Therefore, keeping an eye on and managing the FSW process is crucial to preserving the caliber of the weld joints. The current study aims to investigate the changes in the mechanical characteristics and microstructure of the FSWed AA5052-H111 and AA6061-T6 joints. To perform the FSW experiments, we varied TRS, TTS, and TPP on plates that were 5 mm thick and had a butt joint structure. Following welding, the microstructure of the weld zones was examined to observe how the grains had changed. The joint’s tensile strength reached a maximum of 227 MPa for the square-shaped TPP, and the micro-Vickers hardness test results showed a maximum of 102 HV at the weld nugget zone (WNZ). Full article

Background: Ferrous metals are used extensively in the manufacturing of plates, pins, Kirschner wires (K-wires), and screws, and in the performance of partial and total joint replacement surgeries for the shoulder, elbow, and wrist joints. The primary surgical procedures commonly performed are hip and knee replacement surgeries. Metals possess a combination of high modulus, yield point, and ductility, rendering them well suited for load-bearing applications, as they can withstand significant loads without experiencing substantial deformations or permanent alterations in their dimensions. Application of metals and alloys is of prime importance in orthopedics as they lead the way to overcoming many issues encountered in implant use. In some instances, pure metals are used, but alloys consisting of two or more elements typically exhibit greater material characteristics, including corrosion resistance as well as toughness. The first item to address when selecting a metallic implant material is its biocompatibility. In this regard, three classes of materials are also commonly known as biomedical metals—316L stainless steel, pure titanium, and titanium alloys. Objective: The aim of this work is to create a model describing the material behavior and then simulate the metals under a load of 2300 N, which is equivalent to plastic loading. Methods: Under ten different case studies, a sub-routine was developed to combine the material characteristics of titanium and 316L stainless steel with the software. Results: The outcomes of the research were then investigated. A femur model was created using ANSYS software, and two materials, stainless steel and titanium, were used. The model was then exposed to a force of 2300 N. Full article

Nickel–titanium carbide (Ni-TiC) coatings were synthesized on Q235 steel via double-pulse electrodeposition to enhance surface properties. The influence of TiC concentration on surface morphology, microstructure, and performance was systematically studied using SEM, TEM, XRD, microhardness testing, wear analysis, and electrochemical methods. At low TiC concentrations (2–4 g/L), the coatings exhibited typical cell-like morphology. At 8 g/L, the coating showed a dense structure, refined grains, and broad Ni diffraction peaks. TEM analysis revealed nickel and TiC grain sizes of 97.82 nm and 34.75 nm, respectively. The plating rate remained stable (~36.94 mg·cm⁻²·h⁻¹), while surface roughness increased with TiC content. The 8 g/L TiC coating achieved the highest microhardness (743.13 HV), lowest wear loss (5.43%), and superior corrosion resistance, with a self-corrosion current density of 5.27 × 10⁻⁶ A·cm⁻² and polarization resistance of 7705.62 Ω·cm². These enhancements are attributed to uniform TiC dispersion and grain boundary pinning. Thus, 8 g/L TiC is optimal for fabricating Ni-TiC coatings with improved mechanical and electrochemical performance. This work demonstrates a practical strategy for developing high-performance Ni-based composite coatings via double-pulse electrodeposition. Full article

Athysanini is one of the largest tribes within Deltocephalinae, which is a vast cosmopolitan subfamily of leafhoppers (Hemiptera: Cicadellidae) with many genera known to occur in the Neotropical realm. Peruvian forests house up to 16 genera of Athysanini and, so far, are strongly restricted to this region. In this contribution, a new species of the leafhopper genus Andanus Linnavuori, 1959, Andanus acanthophallussp. nov., is described based on pinned museum specimens. Illustrations and a diagnosis for all species to segregate them in the genus are provided. A dichotomous key to all known species and distributional notes are also given. The new species can be easily separated from others by (1) overall color light orange to stramineous, (2) the pronotum lacking marks or transverse medial bands, (3) a row of very long fine setae on the outer lateral margin of the subgenital plate, (4) apophysis of style straight without lateral projection but minute tooth on inner side, and (5) an aedeagal apex bifid with a pair of processes directed anterad and posterad. The valid status and current position of Andanus based on similarities to other Neotropical genera is discussed. Full article

This paper reports the improved thermal and drying performance of a solar air heater powered by real solar irradiance and equipped with a tree-like fractal-based cylindrical pin (SAH-TFCP) as a turbulator for drying applications. The main purpose of this work is to demonstrate the SAH-TFCP’s improvement potential based on its thermal and drying performance as compared with a conventional solar air heater based on a flat-plate absorber (SAH-FP). The test was implemented based on solar time from 8:30 to 17:30 under Thailand’s climatic conditions at a latitude angle of 14° and a longitude angle of 100°. Turmeric slices were used to evaluate the SAH’s drying performance. The thermal efficiency, moisture content wet basis (MC_wb), drying rate (DR), and drying efficiency were measured as parameters of interest to assess the improvement potential of the SAH-TFCP over the SAH-FP. The results indicate that the SAH-TFCP provides better thermal and drying performance than the SAH-FP. A higher flow rate yields a higher thermal efficiency and a greater improvement potential. The improvement potential is around 44–85%. The drying efficiency of the SAH-TFCP is always higher than that of the SAH-FP and has an improvement potential of 32–44%, depending on the airflow rate. Full article

Deepening the understanding of composite and metal joint methodologies applied in the aerospace industry is crucial for minimizing operational expenditures. Current investigations are focusing on innovative joining techniques that incorporate additive manufactured rivet pins. This research aims to analyze the mechanical strength of these joints for the effective optimization of pin profiles. Through extensive study of the impact of pin geometry on joint performance, we derived the optimal pin design, considering various initial parameters with the objective of minimizing stress concentration in the pin structure. The joint configurations of metal to composite interfaces were systematically examined using finite element analysis and lap shear testing, which included a singular pin and an adhesive-bonding layer. Numerical simulations reveal that the maximum shear stress in the pin is located at the junction between the base of the pin and the metal plate. By optimizing the shape and dimensions of the pin, both the shear and axial stresses can be significantly mitigated. Following the numerical optimization process, a series of enhanced pins have been produced via additive manufacturing techniques to facilitate mechanical testing. The experimental data obtained align closely with the simulation results, thereby reinforcing the validity of the optimization. The optimal configuration for a single pin, involving a 60° angle and a total height of 3.43 mm, achieves the minimum shear stress. Based on these findings, further investigations are underway to explore optimized designs utilizing multiple pins. This paper presents the results of the single pin study, whereas the findings pertaining to the ongoing investigation on the multi-pin configuration will be disseminated in subsequent publications. Full article

Efficient bacterial lysis and RNA purification are essential for molecular diagnostics and biosensing applications. This study presents a piezoelectric platform integrated with gold-plated RNA capture pins (RCPs) functionalized with synthetic oligonucleotides to extract and enrich E. coli 16S ribosomal RNA (rRNA). The 3D-printed device enables selective bacterial capture using E. coli-specific aptamers and incorporates a piezoelectric transducer operating at 60 kHz to facilitate bacterial cell wall disruption. The platform demonstrated high specificity for E. coli over B. cereus, confirming aptamer selectivity. E. coli viability assessment demonstrated that positioning the piezoelectric plate in contact with the bacterial suspension significantly improved the bacterial lysis, reducing viability to 33.68% after 15 min. RNA quantification confirmed an increase in total RNA released by lysed E. coli, resulting in 10,913 ng after 15 min, compared to 4310 ng obtained via conventional sonication. RCP-extracted RNA has a threefold enrichment of 16S rRNA relative to 23S rRNA. RT-qPCR analysis indicated that the RCPs recovered, on average, 2.3 ng of 16S RNA per RCP from bacterial suspensions and 0.1 ng from aptamer-functionalized surfaces. This integrated system offers a rapid, selective, and label-free approach for bacterial lysis, RNA extraction, and enrichment for specific types of RNA with potential applications in clinical diagnostics and microbial biosensing. Full article

Friction surfacing (FS) is a solid-state process for depositing metallurgically bonded coatings for corrosion and wear protection. It is particularly attractive for depositing coatings in materials that are difficult to fusion deposit. Stellite 6 is one such material, which is widely used as a protective coating on steel structures to combat wear and corrosion. In the current study, Stellite 6 was successfully friction-surfaced on low carbon steel plates without using any preheating. The microstructures and wear behavior of Stellite 6 coatings produced using FS were comparatively investigated with those produced using the plasma transferred arc (PTA) process. The PTA coatings showed a cast microstructure consisting of γ-dendrites and an inter-dendritic carbide network. On the other hand, the FS coatings showed a wrought microstructure with dynamically recrystallized grains and fine, uniformly distributed carbide particles. The FS coatings also showed uniform composition across the coating thickness and were undiluted, while the PTA coatings showed significant dilution as well as strong local variations in chemistry. The FS coatings exhibited a 22% increase in hardness (550 HV) compared to the PTA coatings (450 HV). Pin-on-disc dry sliding wear tests showed that the FS coatings (1.205 mm³) were more wear resistant compared to the PTA coatings (6.005 mm³), highlighting their superior mechanical performance. This study uniquely demonstrates the feasibility of depositing Stellite 6 coatings using FS without the need for preheating or post-deposition heat treatments, while achieving superior microstructural refinement, hardness, and wear resistance compared to conventional PTA coatings. Full article

Friction stir welding (FSW) is a solid-state welding method. The effects of tool structure, tool rotational speed, and welding speed in friction stir welding on the temperature, microstructure, and mechanical properties during the welding of 3 mm thick 6061-T6 aluminium alloy and T2 pure copper plates were investigated through experiments, numerical simulations, mechanical property tests, and microstructural observations, with the aim of enhancing welding strength and efficiency. The results showed that the welding heat input increased with the shoulder and pin diameters. When the shoulder diameter was in the range of 10–16 mm, proportional increases in the pin diameter resulted in an approximate increase of 30 °C in the weld centre temperature for every 2 mm increase in shoulder diameter. Compared to welding speed, rotational speed had a more significant effect on the heat input. Compared to the smooth tool, the threaded tool promoted the dispersion of copper particles within the aluminium matrix, facilitating the formation of Al₂Cu phases. This increased the tensile strength of the weld joint from 183 to 236 MPa (a 28.9% improvement), along with a 57% increase in the weld centre hardness. An energy-dispersive X-ray spectroscopy analysis indicated that welding with the threaded tool resulted in the presence of significantly hard and brittle intermetallic compounds, including AlCu and Al₂Cu_, in the stirring zone, which substantially enhanced the weld strength. Full article

Fracture healing in dogs is a complex process influenced by factors such as age, weight, fracture type, and underlying conditions. Among fractures, complex diaphyseal comminuted fractures stand out due to their susceptibility to complications like delayed union or nonunion. Despite the recognized complexities, veterinary-specific data on their incidence, complications, and effective treatment strategies remain surprisingly scarce. This retrospective study analyzed 99 comminuted fractures among 542 long bone fractures treated at the Small Animal Clinic of the Freie Universität Berlin (2007–2014). The femur (n = 42) was most affected, followed by the tibia/fibula (n = 29), radius/ulna (n = 24), and humerus (n = 4). Plates (n = 81) and intramedullary pins or external fixators (n = 16) were used for osteosynthesis. Healing occurred without complications in 72%, while 28% experienced issues such as implant failure or delayed union. Open fractures, high-energy trauma, and >3 fragments were associated with higher complication rates (p < 0.05). Fractures treated with plates healed slower (p = 0.016), and implants were removed later compared to other methods (p = 0.049). This study highlights the challenges of managing complex fractures and emphasizes the need for tailored surgical approaches. It provides new insights into their treatment and outcomes, paving the way for future research to establish standardized veterinary protocols. Full article

This study aims to contribute to the optimization of bio-methanation in bubble columns, making it a more viable alternative to stirred tank reactors. The primary challenge to be addressed is the enhancement of mass transfer, which strongly depends on parameters such as bubble size and gas hold-up. Various disperser designs were examined in a 0.14 mm diameter column, comparing their performance in terms of bubble diameter distribution and gas hold-up. The results indicate that an optimized plate disperser featuring a porous structure outperformed other designs by maintaining high gas retention without significant coalescence. Additionally, newly developed plug-in dispersers allowed for counter-current flow operation, enhancing process flexibility. Commercially available porous pin dispersers produced smaller bubbles compared to the other designs, yielding high gas hold-ups at lower gas velocities. Correlations between disperser type and column design parameters were established, laying the foundation for apparatus optimization. The findings contribute to the development of digital twin models, facilitating the refinement of bio-methanation processes within bubble columns for increased efficiency. Full article

The onboard circuits of EV chargers comprise heat-producing electronic devices such as MOSFETs and diodes for switching and power conversion operations. A heatsink must dissipate this generated heat to extend the devices’ life and prevent component thermal stress or failure. This study primarily investigates the optimal heatsink geometry and pin configuration, which offers the most efficient temperature versus cost performance. MATLAB/Simulink (R2024a) was used to model a Level 1 charger using eight MOSFETs and four diodes. Various heatsink geometries were modeled using the ANSYS (2024 R1) Workbench and Fluent software to optimize the sink’s thermal performance. The analyses were performed under transient conditions using natural and forced cooling scenarios. The 2 mm wide plate fin heatsink with 44 fins yielded the best result. Further enhancement of the best-performing naturally cooled model improved the switches and diodes temperatures by 14% and 4%, respectively. The performance of the heatsink was further improved by applying a cooling fan to achieve an up to 25% diode and 40% MOSFET thermal dissipation efficiency. The results of this study show that the most efficient cooling performance and cost are realized when the optimum combination of fin spacing, proximity from the cooling fan, and fin geometry is selected. Full article

A mid-story pin system to avoid moment-resisting frame column failure during seismic action was proposed recently. The solution consists of a reinforced concrete (RC) pier protruding from the foundations, the steel column connected with the superstructure, and plates and the anchor bolt working as a pinned connection in between. This paper utilizes shell finite element analysis (FEA) models to examine the demanded column-to-beam strength ratio to keep the column elastic and maximize the story drift at the moment of beam buckling of the frame. The method of calculating post-seismic residual strength based on maximal buckling deformation of the beam is also proposed. Full article