Radiative Coefficients Research Articles

Efficiency enhancement of WSe2/In2S3 solar cell by numerical modeling using SCAPS

Tungsten diselenide (WSe2), a transition metal dichalcogenide (TMDC) compound, is considered a promising material for application in thin film solar cells because of its high carrier transport, tunable band gap, and high absorption coefficient. In this work, solar cell structure comprising FTO/In2S3/WSe2 is modeled using one-dimensional solar cell capacitance simulator (SCAPS-1D) software where wide bandgap widely accessible In2S3 is used as a novel buffer layer instead of toxic CdS buffer layer for WSe2-based solar cell. The effect of thickness, doping concentrations, defect density, radiative recombination coefficient, and the electron and hole capture cross-section are analyzed and optimized. After optimizing the device, the effect of operating temperature, shunt and series resistance and back contact work function are also investigated. At an optimized WSe2 absorber layer thickness of 1.5 µm and acceptor density of 1017 cm−3, efficiency of 22.53%, fill factor of 84.98%, open circuit voltage of 1.096 V, and short circuit current density of 24.18 mA/cm2 was obtained. Additionally, a back surface field (BSF) layer comprising amorphous silicon (a-Si) of thickness 0.05 µm is introduced between the absorber layer and the back contact to lessen carrier recombination at the back surface. Therefore, the efficiency rises from 22.53% to 29.5% with a fill factor of 89.53%, open circuit voltage of 1.26 V, and short circuit current density of 26.23 mA/cm2. The simulation results suggest that WSe2-based thin-film solar cells can be designed and fabricated with high efficiency and cost advantage.

Methodology for Obtaining ETo Data for Climate Change Studies: Quality Analysis and Calibration of the Hargreaves–Samani Equation

Reference evapotranspiration (ETo) is an important part of the water cycle, essential for climate studies, water resource management, and agricultural planning. However, accurate estimation of ETo is challenging when meteorological data are insufficient or of low quality. Furthermore, in climate change studies where large amounts of data need to be managed, it is important to minimize the complexity of the ETo calculation. This study presents a comprehensive approach that integrates data quality analysis with two calibration methods—annual and cluster-based—to improve ETo estimates based solely on temperature data from a set of weather stations (WS). First, the quality and integrity of meteorological data from several WS were analyzed to reduce uncertainty. Second, the Hargreaves–Samani equation (HS) is site calibrated using two approaches: (a) annual calibration, where the radiation coefficient (kRs) is adjusted using a data set covering the entire year; (b) cluster-based calibration, where independent radiation coefficients are adjusted for clusters of years and months. The methodology was evaluated for the Alentejo region in Southern Portugal, using data from 1996 to 2023. When using the original HS equation with a kRs = 0.17 °C−0.5, ETo was estimated with errors from 14.9% to 22.9% with bias ranging from −9.0% to 8.8%. The annual calibration resulted in kRs values between 0.157 and 0.165 °C−0.5 with estimation errors between 13.3% and 20.6% and bias ranging from −1.5% to 1.0% across the different weather stations. Calibration based on clusters of months and years produced unclear results. Dry season months showed better results using cluster-based calibration, while wet season months performed poorly regardless of the calibration approach. The results highlight the importance of meteorological data quality and site-specific calibration for refining temperature-based ETo estimation methods, and for the region studied, the gains do not justify the increased complexity of the cluster-based approach.

A computational analysis to enhance performance of CIGS solar cells using back surface field and ZnSe buffer layer approach

Abstract This study aims to enhance CIGS solar cell efficiency while minimizing environmental impact by replacing the toxic CdS buffer layer with a ZnSe buffer layer. The CIGS chalcogenide semiconductor is a promising solar cell absorber material but has faced challenges related to defect-free manufacturing, misaligned buffer layers, and device configuration. Cuprous oxide (Cu2O) and zinc selenide (ZnSe), an inexpensive, eco-friendly, and widely available material, are suggested as a back surface field layer and buffer layer to enhance device performance. This paper proposes a new cadmium-free structure (Al/ZnO: Al/ZnO/ZnSe/CIGS/Cu2O/Ni) to enhance the efficiency of CIGS heterojunction solar cells by reducing charge carrier recombination losses. We utilized SCAPS-1D to simulate photovoltaic (PV) performance and examined the impacts of electron affinity, absorber thickness, interface defect density, operating temperature, radiative recombination coefficient, Mott-Schottky analysis, parasitic resistance, and quantum efficiency on photovoltaic characteristics. Optimization and choosing a suitable buffer and passivation layer gives the device efficiency of 31.13%, followed by VOC (0.92 V), JSC (40.40 mA/cm2), and FF (83.34 %) for the proposed structure. The radiative recombination coefficient found to be 10-13 cm3/s and the parasitic resistance of the solar cell are in good agreement for fabricating high-efficiency solar cells. These findings suggest that CIGS-based heterojunction solar cells represent a cutting-edge method for achieving high-efficiency solar cells that outperform earlier designs.

Acoustic characteristics of bamboo-based guitar – A case study

Bamboo is a fast-growing plant easily obtained in Malaysia. It is commonly used for constructing various solid structures including the guitar. Its unique sound quality makes it different from the traditional wooden guitar. The Yamaha guitar sound was used as reference for the generally preferred guitar characteristics. This work focused on the acoustic characteristics easily obtained using the frequency spectrum analysis via a PicoScope oscilloscope and spectrogram using Adobe Audition. A microphone was used for recording the string sound and yielding the frequency response function. The Fast Fourier Transform (FFT) spectra showed that the Yamaha guitar had less partials compared to the bamboo guitar, except string 4. Strings 1, 2, and 3 showed a regular signal from the Yamaha guitar whereas the bamboo guitar showed an irregular pattern with significant overtone. The intensity of the partials in the bamboo guitar displayed a recognizable pattern, i.e., a reduction of partial intensity amplitude proportional to increasing frequency in strings 4, 5, and 6. Some random partials appeared between the harmonics in string 1, 2, and 3 from bamboo guitar whereas the absence of partials in the Yamaha guitar could be due to the higher radiation coefficient of wood, which displays a different timbre.

Optical properties of a hollow cylindrical quantum wire in a parallel applied magnetic field

In this theoretical study, we investigate optical properties of a hollow cylindrical quantum wire in the presence of a homogeneous magnetic field. The magnetic field is applied parallel to the axis of the quantum wire. The investigations were achieved by solving the Schrödinger equation within the effective mass approximation. The optical properties studied were absorption coefficient (AC) of electromagnetic radiation and changes in refractive index (CRI) of the hollow cylinder. The parallel applied magnetic field lifts the degeneracy of states of opposite angular momentum (the ±|m|\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm |m |$$\\end{document} states, m being the angular momentum quantum number) known as the Zeeman splitting. As such, in the presence of magnetic field, AC splits into two branches, one corresponding to a transition involving the positive m states and the other corresponding to a transition involving the negative m states. Increase in intensity of the electromagnetic radiation reduces the magnitude of the AC. Presence of inner radius of the hollow cylindrical wire lowers transition energies. Apart from absorption due to the (m=0→±1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(m=0 \\rightarrow \\pm 1)$$\\end{document} transitions, the presence of the inner radius also facilitates absorption due the (m=-1→0)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(m=-1\\rightarrow 0)$$\\end{document} transition as the magnetic field strength increases, a phenomenon that does not happen in solid cylindrical quantum wires. The presence of the inner radius also enhances AC in strong magnetic field. Increase in intensity of the electromagnetic radiation affects the CRI (here considered up to third order), introducing a normal dispersion region in an otherwise anomalous region. The parallel magnetic field also splits the CRI depending on the sign of the m states involved in the transitions.

A comparative numerical simulation study of CIGS solar cells with distinct back surface field layers for enhanced performance

The objective of this study is to explore the impact of various back surface field (BSF) layers including copper aluminium oxide (CuAlO2), Copper Antimony Sulphide (CuSbS2), Formamidinium tin triiodide (FASnI3), poly (3-hexylthiophene) P3HT to boost the output of conventional baseline CIGS solar cells structured. The device performance increases because of the minimized surface recombination velocity through heavily doped BSF layers, which increases the electric field at the rear contact. Among all proposed BSF layers CuAlO2 gives the best photoconversion efficiency (η) of 24.61 % followed by fill factor (FF) of 83.11 %, short circuit current density (JSC) of 35.87 mA/cm2, and open circuit voltage (VOC) of 0.82 V with quantum efficiency (QE) of ∼92 % for the whole visible range with the onset happening at ∼ 560 nm, thanks to the enhancement of carrier collection when BSF layer is incorporated. The novelty in this work is that for the first time with the CuAlO2 BSF layer, 24.61 % efficiency is reported at 1 μm CIGS layer thickness. We also examined how different BSFs affect the PV performance of the devices. The effect of temperature, the doping concentration of the BSFs, varying gallium proportion, JV & QE analysis, band diagram, and radiative recombination coefficient are varied to observe their impact on the PV parameters. This research introduces novel CIGS/CdS heterojunction configurations using various BSF layers to enhance efficiency, supporting the advancement of ultrathin, flexible, and tandem solar cell applications.

Applying heterogeneous building materials for the protection of people against electromagnetic radiation

The object of this study is the processes of shielding electromagnetic radiation by building and facing materials. The research is aimed at solving the problem of ensuring the electromagnetic safety of people by improving the composition and structures of building and facing materials. Means for improving the electromagnetic safety of people under industrial and domestic conditions using non-homogeneous building materials have been determined. The shielding properties of reinforced concrete structures were studied. A methodology for increasing their efficiency depending on the amplitude-frequency characteristics of the radiation that needs shielding has been devised. The efficiency of electromagnetic radiation shielding by heterogeneous dielectric building materials based on cement concrete and basalt fibers was determined. It was established that shielding through the refraction of electromagnetic waves on inhomogeneities does not give an acceptable effect. The expediency of covering basalt fibers with a conductive substance to increase the protective properties of materials was substantiated. The protective properties of flat facing material with carbonyl iron content were studied. It has been shown that the properties of materials can be effectively controlled by adjusting the filler. The material's transmission coefficient of ultra-high frequency electromagnetic radiation does not exceed 0.40, and the reflection coefficient – 0.25 with a filler content in the base of 14–15 % by volume. This makes it possible to simultaneously ensure the electromagnetic safety of people and the stable functioning of wireless communication devices. The advantage of the material is the low coefficients of reflection of electromagnetic waves, which does not lead to deterioration of the electromagnetic situation in other areas where people stay. It has been established that the addition of boron nitride to the facing material significantly increases the thermal insulation characteristics of the coating and contributes to the solution of energy saving problems. Adding a layer containing boron nitride to the material provides thermal conductivity coefficients of 0.030–0.031 W/m·K, which is better than known analogs

Exploring the optical behavior and relative translucency parameter of CAD-CAM resin-based composites, polymer-infiltrated ceramic network, and feldspar porcelain

ObjectivesTo evaluate and compare the optical properties and relative translucency parameter of CAD-CAM restorative materials. MethodsFour CAD-CAM materials were evaluated: Lava Ultimate (LU), Grandio Blocs (GB), VITA Enamic (VE), and VITA Mark II (VM). Disk-shaped samples in shade A2-HT were prepared (n = 10) and polished to 1.00 ± 0.01 mm of thickness. Scattering (S), absorption (K), albedo (a) coefficient, transmittance (T%), light reflectivity (RI), infinite optical thickness (X∞), and radiative transfer coefficients (μa, and μ′S) were calculated using Kubelka-Munk method and Thennadil's semi-empirical approach. Root Mean Square Error (RMSE) and Goodness of Fit (GFC) were used as performance optical behavior. Translucency differences were evaluated using the relative translucency parameter (RTP00) and 50:50 % translucency perceptibility and acceptability thresholds (TPT00 and TAT00). ResultsThe spectral distribution of S, K, T%, RI, and X∞ was wavelength-dependent. GFC and RMSE values indicated good spectral behavior matches and good comparative spectral values for RI in LU-GB, LU-VE, and GB-VE, and for K in VE-VM. VM displayed the highest scattering values across the wavelengths, while VE and VM showed lower absorption at shorter wavelengths. LU and GB had the highest transmittance. The X∞ values indicated that all 1.0 mm thick materials could be influenced by the background. No good spectral match and no good comparative spectral values were found between CAD-CAM materials and anterior bovine maxillary specimens. VM had the lowest RTP00 values with perceptible and unacceptable differences compared to CAD-CAM materials evaluated. SignificanceUnderstanding the optical behavior of different CAD-CAM materials was essential for guiding clinicians in material selection and optimizing their clinical performance. The findings confirm that the different compositions and microstructure impact the optical properties and translucency of CAD-CAM restorative materials.

Flame stabilization and emission reduction: a comprehensive study on the influence of swirl velocity in hydrogen fuel-based burner design

PurposeThis study aims to numerically analyse a full-scale burner across a wide range of operating pressure conditions and determine the effect of swirl velocity on flame stabilization, flame holding and combustion performance.Design/methodology/approachThis study uses a numerical analysis approach to investigate a three-dimensional full-scale burner. Modified governing equations are used to determine the effect of swirl velocity on flame stabilization and flame holding. The GR-Mech 3.0 chemical reaction mechanism is used to predict the combustion process. To validate the model, a grid independence study is performed.FindingsThe study reveals that swirl velocity enhances flame stability, resulting in better combustion rates. As the swirl velocity increases, higher flame temperatures are observed due to high convective heat recirculation. The heat transfer coefficient and high radiative extinction coefficient are found to vary based on fuel swirl velocity. The mass fraction of CH4 and CO emphasizes the role of swirl velocity on flame structure. Increasing velocity potentially improves combustion by delaying the process, leading to better combustion and lower emissions.Originality/valueThe findings of this study contribute to the understanding of swirl-stabilized combustion and can guide the development of advanced combustion technologies, making it a valuable addition to the existing combustion field.

Building a model of heating an oil tank under the thermal influence of a spill fire

The object of this study is the process of liquid combustion in a spill, and the subject of research is the distribution of temperature along the wall and roof of a vertical steel tank that is heated under the thermal influence of a spill fire. The heat balance equation for the wall and roof of the tank with oil product was constructed. The assumption of a small thickness of the wall and roof of the tank relative to its linear dimensions makes it possible to move to two-dimensional differential equations of the parabolic type. The equations take into account the radiative heat exchange with the flame, the environment, the internal space of the tank, as well as the convective heat exchange with the surrounding air, the vapor-air mixture, and the liquid inside the tank. Using the methods of similarity theory, estimates of the coefficients of convection heat exchange of the outer surface of the tank with the surrounding air and the inner surface with the vapor-air mixture and liquid in the tank in the conditions of free convection were constructed. The application of the finite difference method for solving the heat balance equations has made it possible to derive the temperature distribution on the surface of the tank at an arbitrary moment in time. It is shown that the value of the coefficient of convection heat exchange of the liquid exceeds the corresponding value for the air-vapor mixture by (1÷2) orders of magnitude. As a result, the part of the wall located below the oil product level is heated to a temperature of (80÷230) °C depending on the viscosity of the liquid. This occurs despite the fact that the value of the mutual radiation coefficient reaches its maximum value at the lower part of the wall. From a practical point of view, this means that the part of the wall above the level of the oil product in the tank can reach dangerous temperature values, and it should be cooled first. The constructed model of tank heating also enables determining the limit time for the start of cooling of the tank.

PyArc: A python package for computing absorption and radiative coefficients from first principles

Light absorption and radiative recombination are two critical processes in optoelectronic materials that characterize the energy conversion efficiency. The absorption and radiative coefficients are thus key properties for device optimization and design. Here, we develop a python package named pyArc that allows rigorous computation of absorption and radiative coefficients from first principles. By integrating several interpolation strategies to augment k-point sampling in reciprocal space, our code is accurate yet highly efficient. In addition to evaluation of the coefficients, our code is capable of intuitive analysis of carrier distribution, facilitating a deeper understanding of the microscopic mechanisms underlying the radiative coefficients. Utilizing GaAs as a prototypical example, we demonstrate how to employ our package to compute absorption and radiative coefficients and to investigate the key features in the electronic structure that give rise to these coefficients. Program SummaryProgram title: PyArcCPC Library link to program files:https://doi.org/10.17632/5x9g9bvhcv.1Licensing provisions: MIT licenseProgramming language: Python 3Nature of problem: Light absorption and radiative recombination processes in semiconductors critically impact the energy conversion efficiency of optoelectronic devices. Developing a method to calculate coefficients of the two processes based on first-principles theory is essential, which not only can help to obtain the key properties of those semiconductor materials and guide the device design, but also can unveil the underlying microscopic mechanisms.Solution method: PyArc, written in the Python language, implements first-principles methodologies for the computation of absorption and radiative coefficients of semiconductors based on Fermi's golden rule. This package takes the electronic eigenvalues and dipole matrix elements of a material computed from first-principles codes such as VASP as input. Dense k-point sampling for the Brillouin zone is achieved through efficient interpolation schemes implemented in our code to acquire well converged results. The functionality of cross-sectional visualization of carrier distribution in our code provides intuitive insights into the fundamental mechanism beneath the charge-carrier radiative recombination process.

Colossal Near-Field Radiative Heat Transfer Mediated by Coupled Polaritons with an Ultrahigh Dynamic Range.

Near-field radiative heat transfer (NFRHT) can exceed the blackbody limit by several orders of magnitude owing to the tunneling evanescent waves. Exploiting this near-field enhancement holds significant potential for emerging technologies. It has been suggested that coupled polaritons can give rise to orders of magnitude enhancement of NFRHT. However, a thorough experimental verification of this phenomenon is still missing. Here this work experimentally shows that NFRHT mediated by coupled polaritons in millimeter-size graphene/SiC/SiO2 composite devices in planar plate configuration can realize about 302.8 ± 35.2-fold enhancement with respect to the blackbody limit at a gap distance of 87 ± 0.8nm. The radiative thermal conductance and effective gap heat transfer coefficient can reach unprecedented values of 0.136 WK-1 and 5440 Wm-2K-1. Additionally, a scattering-type scanning near-field optical measurement, in conjunction with full-wave numerical simulations, provides further evidence for the coupled polaritonic characteristics of the devices. Notably, this work experimentally demonstrates dynamic regulation of NFRHT can be achieved by modulating the bias voltage, leading to an ultrahigh dynamic range of ≈4.115. This work ambiguously elucidates the important role of coupled polaritons in NFRHT, paving the way for the manipulation of nanoscale heat transport, energy conversion, and thermal computing via the strong coupling effect.

Supervised machine learning computing paradigm to measure melting and dissipative effects in entropy induced Darcy–Forchheimer flow with ternary-hybrid nanofluids

This study investigates the change in thermophysical characteristics of Darcy–Forchheimer flow of tri-hybrid nanofluid (THNF) over stretchable porous skin. Machine learning (ML) technique is employed to compare thermal exchange of water-based hybrid nanofluid (HNF), composed of aluminum oxide (Al2O3) and silicon dioxide (SiO2) with THNF by introducing copper oxide (CuO) nanoparticles in HNF. Flow rate profile, dissipation effect, and entropy generation are analyzed with novel, time, and cost-effective evaluation technique. By using similarity parameters, the governing system of partial differential equations (PDEs) is transformed to a system of ordinary differential equations (ODEs). Finite difference method is used for dataset generation by the aid of Python environment, then neural fitting computation technique is utilized for optimized results. Turbulence and randomness are incorporated in the present nonlinear mathematical model which is tackled by artificial intelligence (AI)-based Levenberg Marquardt Neural-Network Algorithms (LMNA), to produce optimized outputs. Velocity, temperature, and entropy profile are evaluated against various influencing factors, such as Forchheimer value, porosity, melting parameter, radiation, Prandtl, Eckert, and Brinkmann coefficient. Numerical and AI-generated outputs and errors graphs with complete neural network training scheme, are portrayed to draw the effective concluding inferences. Enhanced results are beneficial for industrial and engineering production units, for efficient thermal management.

Interruption characteristic of 3%C5F10O/97%CO2 gas mixture in a 40.5 kV circuit breaker

The C5F10O/CO2 gas mixture is one of the most promising SF6 alternative gases at the present stage, which was initially applied in high-voltage electrical equipment. This paper mainly studies the interruption performance of 3%C5F10O/97%CO2 gas mixture (k = 3%) with a charging pressure of 0.6 MPa in high-voltage circuit breakers. First, the thermodynamic parameters, transport coefficient, and net radiation coefficient were calculated for k = 3%. On this basis, a 40.5 kV circuit breaker was used as a prototype to establish the magnetohydrody-namic model for breaking 20 kA short-circuit current, and the arc temperature and pressure distribution in the arc extinguishing chamber of the circuit breaker were calculated. The LC oscillation circuit was used to build an arc-extinguishing characteristic test platform to verify the accuracy of the numerical calculation. Finally, based on the Mayr arc model and the critical electric field strength, the post-arc thermal breakdown and electrical breakdown characteristics of SF6, CO2, and k = 3% were quantitatively analyzed. The results show that under 0.6 MPa, the thermal breakdown performance of k = 3% is about 89.7% of SF6, which is nearly twice higher than that of CO2 and has better thermal breaking ability. The electrical breakdown performance of k = 3% is about 20.4% of SF6, and the probability of electrical breakdown in the front end of the fixed contact is high. This problem should be paid attention to in the design of high-voltage circuit breakers. This study can provide a reference for the development and optimization of environmentally friendly high-voltage circuit breakers.

Effective Lifetime of Nonequilibrium Carriers in Perovskite‐Inspired Cu2AgBiI6

Perovskite‐inspired materials (PIMs) are potential alternatives to lead halide perovskites, as they not only inherit the benign optoelectronic properties but also diminish the stability and toxicity issues of lead halide perovskites. As a newly discovered PIM, Cu2AgBiI6 has exhibited promising potential for photovoltaic applications. However, studies on its fundamental properties related to photovoltaic performance are scarce, particularly from a theoretical perspective. Herein, the effective lifetime of nonequilibrium carriers (photo‐excited charge carriers) is systematically investigated, a critical property affecting the photovoltaic performance of Cu2AgBiI6, based on the nonadiabatic molecular dynamics simulations. It is found that under the standard solar spectrum illumination, the dominant recombination mechanism affecting the effective lifetime can be band‐to‐band nonradiative decay, band‐to‐band radiative decay, or Shockey–Read–Hall defect‐assisted decay. The specific mechanism is highly dependent on the radiative recombination coefficient and the density of defect recombination levels. The effective lifetime can vary from 0.1 ms to 10 ns. When considering different illumination conditions (generation rates), Auger decay can also become the dominant recombination mechanism, with the effective lifetime varying from 0.1 s to 0.1 ns. These findings can be vital for further experimental researches aimed at enhancing the power conversion efficiency of Cu2AgBiI6‐based solar devices.

Combination of MSC Marc and SE-FIT to simulate the direct laser deposition of the multi-layer Ti–6Al–4V

Modeling the impact of a laser heat source on Ti6Al4V deposition is crucial for optimizing additive manufacturing, particularly in multi-layer contexts. This modeling provides insights into the material’s behavior during the Ti6Al4V manufacturing process. In this study, simulations using MSC Marc were conducted to model the impact of a laser heat source on the deposition of the multi-layer Ti–6Al–4V (abbreviated as Ti6Al4V) using the Ti–6Al–4V metal powder, followed by SE-FIT simulation to characterize their deposition morphology. MSC Marc was utilized to simulate the impact of a laser heat source on the Ti6Al4V, with a focus on identifying the melting area. Thermal conductivity was represented in the form of a chart as a function of temperature. Next, the morphology after deposition was defined using SE-FIT based on volume and boundaries. In the MSC Marc numerical model, a combined heat transfer coefficient of radiation and convection was applied to the convective coefficient. In the section depicting the multi-layered deposition morphology, a laser with 750[Formula: see text]W power was utilized at a speed of 3.3[Formula: see text]mm/s. After simulation, the resulting layer height and appearance were compared with the literature for a 25-layer composite. The practical implications of this research extend to the broader field of laser-induced heat deposition on Ti6Al4V deposition, which has applications beyond titanium alloys. The findings may contribute to advancements in the design and manufacturing of various metal components, impacting industries such as automotive, electronics and energy.

Pathway to Multi-Response Characterization of the Improved Elliptical Vessel Solar Receiver for Efficiencies Maximization

Studies on the pathway to multi-response characterization of the improved elliptical vessel solar receiver for environmental sustainability has been studied. The materials were sourced based on categories of components element: support mechanisms made of mild steel plates, bolts, nuts, clamps, and water as heat transfer fluid. The reflector was made of aluminum foil tape while the vessel has a glass cover fitted with bolts and nuts, the receiver is made of copper pipe, aluminum pipe, galvanized iron pipes, and stainless steel pipes. They are fitted into the vessel with chlorinated polyvinyl chloride 3⁄4 pipes, and journal-bearing mechanisms. Furthermore, glass cover attachment reduces radiative heat loss coefficient by eliminating wind influence and increases heat flux inside the vessel thereby improving heat transfer, hence improving the overall system's efficiency. The pathway to multi-response characterization showed that the average experimental thermal efficiency rose from 9.83% to 12.55% and from 4.42% to 7.03% for Polyurethane coated Copper and Aluminum respectively. It reduced from 9.83% to 8.53% and from 8.10% to 6.50% respectively for Polyurethane coated Galvanized Iron and Aluminum. This depicts the gleam appearance of Polyurethane coating on Galvanized Iron and stainless steel thus reducing their heat absorption coefficient and in turn reducing their efficiency.

EUV Radiation in the Range of 10–20 nm from Liquid Spray Targets Containing O, Cl, Br and I Atoms under Pulsed Laser Excitation

The article describes the results of an investigation to determine the values of radiation intensities emitted by O-, Cl-, Br-, and I-containing liquid spray targets in absolute units in the wavelength range 10–20 nm when excited by pulsed laser radiation. The conversion coefficients of laser radiation into the EUV radiation are given for some wavelengths. The authors’ specially designed pulse extrusion liquid supply system was used to form the liquid spray targets. An Nd:YAG laser with λ = 1064 nm, τ = 8.4 ns, and Epulse = 0.8 J was used to excite the targets. Spectral measurements were made using a grazing incidence grating spectrometer–monochromator. The absolute intensities of a number of emission lines were also measured using a Bragg spectrometer based on a Mo/Be multilayer X-ray mirror, calibrated by both sensitivity and wavelength. The high values of absolute intensities of the liquid targets in the extreme ultraviolet wavelength range were demonstrated.

Elastic self-adhesive radioabsorbing materials

The article considers creation of elastic self-adhesive radio absorbing materials for frequency range of 2-7 GHz. Carbonyl iron is widely used in the production of radioabsorbing materials. Materials with this filler have a low absorption of electromagnetic radiation, and more reflect it. The main advantage of this filler is that it is produced by domestic manufacturers in industrial volumes. Another filler used for the production of radioabsorbing materials is carbon fibre. Materials on this filler have a high absorption coefficient of electromagnetic radiation, but operate in a very narrow frequency range. Therefore, in order to increase electromagnetic absorption and extend the frequency range, a certain amount of carbon fibre is introduced into the composition of the radioabsorbing material containing carbonyl iron. It is shown that in this case absorption of electromagnetic radiation reaches 93%. The material is intended for protection of premises and equipment against electromagnetic radiation.

Features of heat/mass transfer and explosive water boiling at the laser fiber tip

Experimentally, as well as using numerical simulation methods, the features of the processes of heat and mass transfer and explosive boiling of water, initiated by continuous laser radiation with λ = 1.94 μm, emerging from the tip of the laser fiber, are studied. The trajectories of the microvolume with the maximum temperature of the superheated liquid under laser heating, in which the probability of explosive boiling up is maximum, are determined. The calculations took into account changes in the density of superheated water and the dependence of the absorption coefficient of laser radiation on temperature. Using acoustic methods and high-speed video recording, it is shown that during explosive boiling up, the duration of the leading front of the acoustic signal is ∼300 ns. Such a long duration of pressure rise at the receiving point is explained by the fact that explosive boiling occurs in a wide area of superheated liquid near fiber tip, when the nuclei located in it are stimulated by an initially arising pressure pulse.