Experimental Investigation Research Articles

Enhancing the Machining Performance during Micro-Channel Fabrication on Quartz Ceramic with Rotary ECDM Process

ABSTRACT Quartz ceramic has become integral to various electromechanical applications attributed to its worthier piezoelectric, thermal, mechanical, and optical properties. Electrochemical discharge machining (ECDM) is evolving as an efficacious hybrid micromachining technique for processing non-conductive materials. Despite its promising potential, the ECDM process encounters several challenges, including ineffective flushing, limited electrolyte replenishment, etc. which hinder its overall efficiency. Therefore, the current research work aims to strengthen the performance of microchannel fabrication on quartz ceramic by incorporating tool rotation in the ECDM process. The theoretical analysis of gaseous layer development, coupled with experimental investigations, highlights how tool rotation stabilizes the gas film, leading to more controlled discharge energy, reduced width overcut, and a thinner heat-affected zone. Optimal parameters were identified, achieving a material removal rate of 0.271 mg/min and a WOC of 102 μm. Additionally, the successful fabrication of a microfluidic chip demonstrates the technique’s potential for industrial applications like lab-on-chip devices, MEMS, and biosensors.

Assessment of bacteria-based self-healing concrete through experimental investigations — a sustainable approach

This study aims to evaluate the destructive and non-destructive strength parameters of bacterial concrete with different grades (M20, M25, M30) and cell counts (10^5 and 10^6 cells/ml) using Bacillus subtilis. Additionally, cost analysis and cost–benefit comparisons were conducted for each mix. The effectiveness of B. subtilis in resisting high temperatures was also examined. Findings indicate a 25–40% increase in strength parameters in bacterial concrete compared to conventional concrete. Bacterial mixes consistently showed velocities above 4.45 km/s, indicating excellent quality, surpassing conventional concrete. Notably, bacteria with a cell count of 10^5 cells/ml exhibited greater strength than 10^6 cells/ml across all grades. Cantabro loss tests revealed a 15–25% reduction in wear and tear for bacterial concrete. The bacterial specimens also showed significantly lower strength loss at higher temperatures. This study underscores the potential of bacterial-based self-healing concrete for specific construction applications, offering high temperature resistance, increased strength, and reduced wear and tear.

Reducing Intrinsic Carrier Recombination in Au/CuTCPP(Fe) Schottky Junction Through Spin Polarization Manipulation for Sensitive Photoelectrochemical Biosensing.

Schottky junctions have been widely applied to facilitate charge carrier separation through the formation of an internal electric field (IEF). However, the notably restricted spatial distribution of the IEF weakens the promotion of intrinsic carrier separation. In this study, we unveil that Au nanoparticles (NPs) in the Au/CuTCPP(Fe) Schottky junction can manipulate the spin polarization of CuTCPP(Fe) to inhibit inner carrier recombination. Experimental investigations and theoretical calculations reveal that the introduction of Au NPs leads to an increased population of spin-polarized electrons, effectively suppressing inner charge carrier recombination in CuTCPP(Fe) by employing the spin mismatch between spin-polarized photoexcited carriers. Moreover, as a typical active site for the oxygen reduction reaction, the oxygen adsorption configuration on spin-polarized Fe single-atom sites in Au/CuTCPP(Fe) is further optimized, resulting in boosted interfacial reactions. Leveraging the thiocholine-induced poisoning of the active sites and the magnetic-enhanced photoelectric response, Au/CuTCPP(Fe) is harnessed to develop a photoelectrochemical biosensing platform for organophosphorus pesticides. This work offers a promising method for manipulating the spin polarization of semiconductors in heterojunctions to mitigate intrinsic charge carrier recombination.

Experimental investigation and simulation of a helical coil heat exchanger with hematite thermal reservoir

Experimental investigation and simulation of a helical coil heat exchanger with hematite thermal reservoir

Field emission study on atomically heterogeneous micro-metallic emitters produced by ion beam from inert gas plasmas

Abstract High doses of irradiation in extreme environments, such as space or fusion reactors, cause significant substrate modifications, requiring systematic experimental data to understand the underlying processes. This study explores the effects of ion irradiation on aluminum and titanium sheets used in spacecraft, with fluence levels ranging from 3.8 to 4.0 × 1018 cm-2, employing 2 keV ions of argon and krypton generated by 2.45 GHz microwave plasma to investigate surface modifications and atomic heterogeneity induced by ion implantation, while minimizing complications from chemical bond formation. This experimental investigation is further extended to understand the impact of implanted ions and surface modifications on electron emission properties in high electric fields. Notable field emission improvements are observed: for Kr-irradiated Al, turn-on potential is 2.3 ± 0.6 kV, a maximum current is 3.4 ± 0.3 nA, and enhancement factor is 1059, with Kr incorporation at 76.9 %; for Ar-irradiated Ti, turn-on potential is 1.6 ± 0.2 kV, a maximum current is 9.8 ± 0.8 nA, and enhancement factor is 2540, with Ar content at 88.5 %. This study thus systematically discusses the discernible variations in field emission properties with the morphological changes, ion implantation percentages, and local work function measurements, providing valuable insights into the effects of inert gas ion irradiation on metallic substrates.

An Experimental Investigation on Microstructural, Mechanical and Biocompatibility Properties of Ti6Al4V Alloy Subjected to Equal Channel Angular Pressing Process

An Experimental Investigation on Microstructural, Mechanical and Biocompatibility Properties of Ti6Al4V Alloy Subjected to Equal Channel Angular Pressing Process

Ab initio investigation of a hypersonic double cone experiment.

This article presents a direct molecular simulation (DMS) of a reactive Mach 8.2 oxygen flow over a double cone geometry. The free stream conditions and article configuration generate a flow with thermal and chemical nonequilibrium, which are common attributes of hypersonic flight. This scenario was first studied experimentally at Calspan University of Buffalo Research Center's test facility. DMS is a particle method that uses quantum mechanically derived interaction potentials to simulate molecular collisions within a flow field. Since these interaction potentials are the only modeling inputs used in the simulation, all flow features can solely be attributed to the ab initio potential energy surfaces. Hence, providing a comparison of a hypersonic ground test and numerical data anchored to quantum mechanics. The fundamental nature of DMS is leveraged to investigate molecular level mechanisms prevalent in the flow, and comparisons with lower fidelity simulations are presented to highlight the role of these first principles calculations as benchmark solutions.

Study on the electromagnetic properties of the [sc][q¯b¯] and [sc][s¯b¯] states with JP=1+

A systematic study of the electromagnetic properties of exotic states is conducted to elucidate their nature, which continues to be the subject of controversy and incomplete understanding in the field. In this study, the magnetic dipole and quadrupole moments of the tetraquarks [sc][q¯b¯] and [sc][s¯b¯] with JP=1+ are extracted in the context of a compact diquark-antidiquark configuration with the help of the QCD light-cone rules method. The magnetic dipole moments are given as μ[sc][u¯b¯]=-2.12-0.59+0.74μN, μ[sc][d¯b¯]=1.66-0.46+0.60μN, and μ[sc][s¯b¯]=2.01-0.50+0.61μN. The order of magnitude of the magnetic dipole moments would suggest that these outcomes may be achievable in forthcoming experiments. The magnetic and quadrupole moments of hadrons represent another important observable, along with their mass and decay width, contributing to our understanding of the underlying quark structure and dynamics. Therefore, we hope that the results of this study will prove useful in theoretical and experimental investigations, which we anticipate will be an interesting research topic.

Numerical and Experimental Investigations on an Angular Approach Flowfield (AAF) Geometry for PEM Fuel Cells

Numerical and Experimental Investigations on an Angular Approach Flowfield (AAF) Geometry for PEM Fuel Cells

Experimental and theoretical investigation on seismic performance of Seawater Sea sand cementitious columns reinforced with GFRP bars and PVA fibers

Experimental and theoretical investigation on seismic performance of Seawater Sea sand cementitious columns reinforced with <scp>GFRP</scp> bars and <scp>PVA</scp> fibers

Creation of dopant-plasmon synergism in double perovskites for bias-free photoelectrochemical synthesis of bromohydrins and hydrogen peroxide.

The integration of photoexcited charge carriers into the synthesis of valuable chemicals offers substantial sustainability benefits, particularly by replacing toxic and costly oxidants and reductants typically used in conventional processes. The efficiency of such transformations is fundamentally governed by the ability to optimize light absorption and charge carrier dynamics within photoelectrodes/photocatalysts. Herein, we present a Cu+/Cu2+-substituted double perovskite Cs2AgBiBr6 photoanode, embedded with plasmonic Ag nanoparticles, for bias-free photoelectrochemical production of bromohydrins and H2O2. Spectroscopic analyses, coupled with three-dimensional finite-difference time-domain simulations, demonstrate that the inclusion of Ag nanoparticles significantly enhances electromagnetic energy utilization and improves carrier separation efficiency. The synergistic effect of the Cu2+ and Ag nanoparticles results in a 7-fold increase in the yield of 2-bromo-1-phenylethanol, compared to pristine Cs2AgBiBr6, alongside an impressive H2O2 productivity of 25.8 μmol h-1 cm-2. Experimental and theoretical investigations reveal that the Cu2+ substitution strengthens Br- adsorption and oxidation, promoting the bromohydroxylation of alkenes via electrophilic addition in the bulk solution. These findings offer critical insights into the design of advanced metal halide perovskites for sustainable and solar-driven chemical transformations.

Theoretical and Experimental Investigation of the Thermal Stability of a Cycloid Speed Reducer

Theoretical and Experimental Investigation of the Thermal Stability of a Cycloid Speed Reducer

Experimental investigation of nano-additive enhanced Azolla biodiesel blends for improved diesel engine performance and emission mitigation

Abstract This study investigates the performance and emission characteristics of a diesel engine fueled with Azolla microphylla biodiesel blends and the effects of aluminium oxide (Al2O3) and copper oxide (CuO) nanoparticles as fuel additives. Azolla microphylla, an aquatic fern, was used to produce biodiesel through a transesterification process. Diesel fuel was blended with Azolla biodiesel in ratios of 10:90 (B10), 20:80 (B20), and 30:70 (B30). Engine performance parameters, including brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and emissions of carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and smoke, were evaluated. The results showed that the B30 blend exhibited the highest BTE under maximum load conditions. To address the high viscosity and poor combustion performance of higher biodiesel blends, Al2O3 and CuO nanoparticles were added to the B30 blend at concentrations of 50 ppm and 100 ppm. The B30 blend with 100 ppm Al2O3 nanoparticles demonstrated the highest BTE and the lowest emissions of HC, CO, CO2, and smoke compared to the other test blends. The improved combustion and reduced emissions were attributed to the enhanced heat transfer and catalytic properties of the Al2O3 nanoparticles. These findings suggest that Azolla biodiesel, especially when combined with Al2O3 nanoparticles, can be a viable and sustainable alternative to conventional diesel fuel.

Experimental Investigation of Fire—Technical Characteristics of Selected Flame Retardants for the Protection of Wooden Structures

Experimental Investigation of Fire—Technical Characteristics of Selected Flame Retardants for the Protection of Wooden Structures

Abrasive Flow Material Removal Mechanism Under Multifield Coupling and the Polishing Method for Complex Titanium Alloy Surfaces

This study addresses the challenge of uneven surface quality on the concave and convex regions during the precision machining of titanium alloy thin-walled complex curved components. An electrostatic field-controlled liquid metal-abrasive flow polishing method is proposed, which is examined through both numerical simulations and experimental investigations. Initially, a material removal model for the liquid metal-abrasive flow under electrostatic field control is developed, with computational fluid dynamics (CFD) and discrete phase models employed for the numerical simulations. Subsequently, the motion characteristics of liquid metal droplets under varying amplitudes of alternating electric fields are experimentally observed within the processing channel. This serves to validate the effectiveness of the proposed method in enhancing surface quality uniformity across the concave and convex regions of titanium alloy thin-walled complex curved components. Our results demonstrate that by controlling the distribution of the electric field in regions with varying flow strengths, the roughness differences between the concave and convex surfaces of the workpiece are reduced to varying degrees. Specifically, in the experimental group subjected to a 24 V alternating electric field, the roughness difference is minimized to 58 nm, representing a 44% reduction compared to conventional abrasive flow polishing. These findings indicate that the proposed electrostatic field-controlled liquid metal-abrasive flow polishing method significantly enhances the uniformity of surface polishing on concave and convex areas of titanium alloy thin-walled complex curved components.

An Experimental Investigation into the Application of Acoustic Emission Characteristics to Observe the Damage During the Spalling Process of Granodiorite

An Experimental Investigation into the Application of Acoustic Emission Characteristics to Observe the Damage During the Spalling Process of Granodiorite

Enhanced Non-Invasive Radio Frequency Heating Using 2D Pyrite (Pyritene).

Radiofrequency (RF) heating is a new, less invasive alternative to invasive heating methods that use nanoparticles for tumour therapy. But pinpoint local heating is still hard. Molecular interactions form a hybrid structure with unique electrical characteristics that enable RF heating in this work, which explores RF heating in a biological cell (yeast)-2D FeS2 system. Substantial processes have been uncovered via experimental investigations and density functional theory (DFT) computations. At 3 W and 50 MHz, RF heating reaches 54°C in 40 s, which is enough to kill yeast cells, while current-voltage measurements reveal ionic diode-like properties. Interactions between yeast lipid molecules and 2D FeSk, as shown by density-functional theory calculations, cause an imbalance in the distribution of charges and the creation of polar, conductive channels. Insights into biological heating applications based on radio frequency (RF) technology are offered by this work, which lays forth a framework for investigating 2D material-biomolecule interactions.

Experimental Investigation and Analysis of Hybrid Laminates

Hybrid composites have gained significant attention from researchers due to their potential as reinforcement materials for composites. This is primarily because of the numerous advantages they offer, including low density, low cost, renewability, biodegradability, and environmental safety, along with mechanical properties that are comparable to those of synthetic fiber composites. In this study, hybrid composites made from natural fibers and glass fibers were fabricated using epoxy resin and a combination of the hand lay-up method and the cold press method. Specimens were cut from the fabricated laminate according to ASTM standards for various tests, including tensile, flexural, and impact tests. The woven fiberglass hybrid composites demonstrated a notable improvement in tensile strength. Consequently, these high-performance hybrid composites display enhanced mechanical characteristics and have wide-ranging engineering applications in industries such as transportation, aeronautics, naval, and automotive.

In situ experimental investigation of fiber orientation kinetics and rheology of polymer composites in shear flow

In this study, we experimentally investigate the fiber orientation kinetics and rheology of fiber-filled polymer melts in shear flow. A novel setup is designed with custom-built bottom and top geometries that are mounted on a conventional rotational rheometer. Shear flow between parallel sliding plates is applied by vertical movement of the top geometry. The axial force measurement data of the rotational rheometer are used to determine the shear stress growth coefficient. The fiber orientation kinetics are measured in situ with this setup using small angle light scattering. We consider a non-Brownian experimental system with short glass fibers for the suspended phase (L/D=8–15) and different polyethylene based materials for the matrix phase. The fiber orientation kinetics are investigated as a function of fiber volume fraction (ϕ=1%, 5%, and 10%) and as a function of the shear rate (γ˙=0.03, 0.55, and 5s−1). Within the studied range, these parameters do not influence the fiber orientation kinetics, and a multiparticle model, based on Jeffery’s equation for single particles, can describe these kinetics. Our results show that, up to the concentrated regime (ϕ≈D/L), fiber-fiber interactions do not influence the fiber orientation in shear flow. Finally, we investigate the shear stress growth coefficient of these composites and demonstrate that a simple rheological model for fiber composites, which assumes a constant, isotropic orientation distribution of the fibers, is able to describe the shear stress growth coefficient of the short fiber composite samples.

Flexural Response of UHPC Wet Joints Subjected to Vibration Load: Experimental and Theoretical Investigation

This study aims to investigate the flexural performance of ultra-high-performance concrete (UHPC) wet joints subjected to vibration load during the early curing period. The parameters investigated included vibration amplitude (1 mm, 3 mm, and 5 mm) and vibration stage (pouring—final setting, pouring—initial setting, and initial setting—final setting). A novel simulated vibration test set-up was developed to reproduce the actual vibration conditions of the joints. The actuator’s reaction force time-history curves for the UHPC joint indicate that the reaction force is stable during the initial setting stage, and it increases linearly with time from the initial setting to the final setting, trending toward stability after 16 h of casting. Under the vibration of 3 Hz-5 mm, cracks measuring 14 cm × 0.2 mm emerge in the UHPC joint. It occurs during the stage from the initial setting to the final setting. The flexural performance of wet joint specimens after vibration was evaluated by the four-point flexural test, focusing on failure modes, load-deflection curves, and the interface opening. The results show that all specimens with joints exhibited bending failure, with cracks predominantly concentrated at the interfaces and the sides of the NC precast segment. The interfacial bond strength was reduced by vibrations of higher amplitude and frequency. Compared with the specimens without vibration, the flexural strength of specimens subjected to the vibration at 3 Hz-3 mm and 3 Hz-5 mm were decreased by 8% and 19%, respectively. However, as the amplitude and frequency decreased, the flexural strength of the specimens showed an increasing trend, as this type of vibration enhanced the compactness of the concrete. Additionally, the calculation model for the flexural strength of UHPC joints has been established, taking into account the impact of live-load vibration. The average ratio of theoretical calculation values to experimental values is 1.01, and the standard deviation is 0.04, the theoretical calculation value is relatively precise.