Direct Energy Research Articles

Synthesis, Spectral Analysis, and DFT Studies of the Novel Pyrano[3,2-c] quinoline-based 1,3,4-thiadiazole for Enhanced Solar Cell Performance

In this study, we synthesized a novel compound, 3-(5-amino-1,3,4-thiadiazol-2-yl)-6-ethyl-4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione (ATEHPQ), through a condensation reaction between 6-ethyl-4-hydroxy-2,5-dioxo-5,6-dihydro-2H-pyrano[3,2-c]quinoline-3-carboxaldehyde and thiosemicarbazide, followed by oxidative cyclization. We characterized ATEHPQ using elemental analysis, IR, 1H and 13C NMR spectroscopy, and mass spectrometry. Density Functional Theory (DFT) calculations with the B3LYP/6-311++G(d,p) basis set were employed to optimize the molecular geometry and analyze global reactivity descriptors, including HOMO-LUMO energies. The Molecular Electrostatic Potential (MEP) map was used to identify reactive sites, and drug-likeness studies indicated potential pharmaceutical applications. Notably, ATEHPQ showed a higher first hyperpolarizability (βtot) compared to urea, suggesting its suitability for nonlinear optical applications. We also determined the Miller indices for ATEHPQ’s preferred orientations using a specialized program. Williamson–Hall analysis revealed an average crystal size of 26.08 nm and a lattice strain of 6.3 × 10−3. The thin films exhibited three distinct absorption peaks at 2.8, 3.41, and 4.21 eV, with a direct energy gap of 2.43 eV. Dispersion parameters from the single oscillator model provided oscillator and dispersion energies of 3.12 eV and 14.21 eV, respectively, with a high-frequency dielectric constant of 4.71. The ATEHPQ thin films, when combined with n-Si, demonstrated significant improvements in photovoltaic performance: the open-circuit voltage (Voc) rose from 0.13 V to 0.521 V, the short-circuit current (Isc) increased from 0.253 mA to 2.94 mA, the fill factor (FF) improved from 0.238 to 0.33, and the efficiency (η) grew from 0.71% to 4.64% with increased illumination intensity. These results highlight the excellent photovoltaic and photodetection capabilities of ATEHPQ thin films, underscoring their potential for advanced optoelectronic and solar cell applications.

Mechanical and Metallurgical Characteristics of Wire-Arc Additive Manufactured HSLA Steel Component Using Cold Metal Transfer Technique

Recently, the application of wire-arc additive manufacturing (WAAM) for the production of metallic products is gaining traction. WAAM is associated with the direct energy deposition technique and therefore has a higher deposition rate (approximately 4 kg/h). For this reason, it is of greater interest than powder-based additive manufacturing techniques. Industrial applications such as marine and offshore structures and pressure vessels for space programs commonly utilize high-strength low-alloy (HSLA) steel. HSLA steel components produced by casting methods exhibit defects due to oxidation. Therefore, cold metal transfer (CMT)-WAAM was adopted in this study to fabricate HSLA steel components. The metallurgical properties were analyzed using microscopic and diffraction techniques. The effects of the evolved microstructures on mechanical properties, such as strength, microhardness, and elongation to fracture, were evaluated. To analyze and test the structure, two regions were selected, namely, top and bottom. Microstructural analyses revealed that both regions were primarily composed of acicular ferrite, polygonal ferrite, and bainitic structures. The bottom region exhibited superior mechanical properties compared with the top region. The improved strength at the bottom region can be ascribed to the formation of a high density of dislocations and finer grains.

Evolution of microstructure and mechanical property enhancement in wire-arc directed energy deposition with interlayer machining

Wire-Arc Directed Energy Deposition (Wire-Arc DED) has emerged as a promising additive manufacturing technique known for its high deposition rates. However, the variability in microstructure and mechanical properties (e.g., hardness) of the manufactured components poses significant challenges. This study delves into these issues, focusing on the influence of interlayer machining on the microstructural evolution and mechanical properties of thin-wall Wire-Arc DED structures. It is shown that as-built Wire-Arc DED structures exhibit a pronounced microstructure variation between different regions along the build direction, primarily governed by the differences in thermal history. In contrast, a Hybrid Wire-Arc DED process that integrates interlayer machining into the build process to induce severe plastic deformation leads to a microstructure characterized by refinement and homogenization, compared to a Wire-Arc DED process. This study provides insights into the impacts of plastic deformation due to machining and thermal cycling due to subsequent layer depositions on the microstructure and hardness obtained in Wire-Arc DED and Hybrid Wire-Arc DED processes, highlighting the potential of hybrid manufacturing to generate tailored microstructures to enhance the mechanical performance of functional components.

Photocatalytic activity of XInS2 (X: Ag, Cu) nanoparticles for oxidative desulfurization of diesel fuel

In this work, Ag(Cu)InS2 semiconductor nanoparticles were synthesized via microwave and solvothermal methods. The effects of synthetical parameters on the structure and morphology of the nanoparticles were characterized by XRD, SEM, TEM, UV–Vis, and EDX. The experimental results reveal that the AgInS2 compound can be crystallized in two different phases, which are tetragonal and orthorhombic. The nanoparticles size of AgInS2 is about 15-16 nm and the direct band gap energy (Eg) of 2.041. While CuInS2 has the average particle size of around 25 nm and Eg value of 3.38 eV. The catalytic activity of both AgInS2 and CuInS2 materials were performed for photocatalytic oxidative desulfurization of sulfur compounds in the commercial diesel fuel under visible light. The maximum oxidation efficiency of 98.05% was achieved for AgInS2 catalyst after 8 hours of reaction time.

Prevention of hot cracking in Ni-based superalloy via passivation layer formation during additive manufacturing

We investigated the prevention of hot cracking in a non-weldable Ni-based superalloy by utilizing a passivation layer formed through laser-based directed energy deposition. The addition of Hf to the Ni-based superalloy facilitated the formation of a passivation layer consisting of Hf oxide on the surface of the as-deposited sample. An increase in the amount (thickness) of the passivation layers with increasing Hf content resulted in a reduction in hot cracking occurrence. Specifically, the addition of 2.5 wt% Hf led to the formation of uniformly distributed fine oxides without inducing hot cracks. This passivation layer effectively inhibited the formation of coarsened Mo oxides, which typically occur during oxidation in the liquid state and contribute to the hot cracking of Ni-based superalloy. During oxidation in the liquid state, Hf diffuses out to the surface and forms a passivation layer, thereby suppressing the formation and growth of oxides to sizes large enough to induce hot cracking.

HYDROTHERMAL SYNTHESIS OF NITROGEN-DOPED CQDS OF RUBUS NIVEUS LEAVES FOR FLUORESCENT pH SENSING AND PHOTOCATALYTIC APPLICATIONS

The development of a fluorescent pH sensor and the treatment of wastewater with nanoparticles are both critical topics. The variation in pH impacts the morphology and subsequent properties of the nanoparticles, which are used for their utilization in various fields and the second one gives a better treatment approach for industrial waste entities. The present study examines the effects of these variables on the biologically produced nitrogen-doped carbon quantum dots (NCQDs). Hydrothermal process was performed for the synthesis of the same by using Rubus-niveus leaf extract as a precursor. The UV-Vis spectroscopy analysis shows absorption spectra in the wide range of 200 nm to 800 nm and shows prominent peaks at 236 nm and 392 nm, respectively. Further, the direct energy band gap of 3.65eV was analysed for NCQDs. The SEM image shows flower-shaped particles, and FT-IR analysis indicates the existence of amide, CHO, N-H, and C-N functional groups. XRD pattern showed that the surface morphology of NCQDs is amorphous in nature. A good response was found in the variation of fluorescence intensity with the pH values, confirming the possibility of NCQDs serving as pH sensors. Rhodamine-B (Rh-B) dye's reaction kinetics was revealed for the purpose of analyzing the potential of NCQDs for the degradation of commercial dyes and found to be followed by pseudo-first order kinetics with the correlation coefficient of 0.80.

Evaluation of Band Structure of Single Crystalline Si-Rich SiSn thin Film

We evaluated the bandgap energy and optical properties of single-crystalline silicon-tin (Si1-x Sn x ) thin films utilizing Photoluminescence (PL), spectroscopic ellipsometry (SE), and X-ray photoelectron spectroscopy (XPS). The PL and SE results showed that the indirect and direct bandgap energy decrease with increasing Sn fraction. Furthermore, the change in the direct bandgap energy is larger than the indirect bandgap energy. This shows that Si1-x Sn x approaches the direct transition type. Then, the Sn fraction from the indirect-to-direct bandgap is estimated to be 47.2%. In addition, XPS results showed that the difference in valence band maximum between Si1-x Sn x and pure Si increased depending on Sn fraction. This is responsible for the decrease in the indirect and direct bandgap energy.

Stainless and low-alloy steels additively manufactured by micro gas metal arc-based directed energy deposition: microstructure and mechanical behavior

Stainless and low-alloy steels additively manufactured by micro gas metal arc-based directed energy deposition: microstructure and mechanical behavior

Enhanced high temperature mechanical and oxidation behavior of direct energy deposited TiC/Inconel 718 gradient coatings

While Inconel 718 is commonly employed in high-temperature settings, its performance at elevated temperatures is notably diminished in comparison to its performance under ambient conditions. In this study, Inconel 718 (IN718), Inconel 718 with 5 layer of Inconel 718–5 wt% TiC gradient coatings (CG-5), and Inconel 718 with 5 layer of Inconel 718–10 wt% TiC gradient coatings (CG-10) were fabricated using direct energy deposition (DED) to investigate the influence of TiC content on the mechanical and oxidation properties at elevated temperatures through the regulation of microstructural changes. Following the incorporation of TiC, the microstructures underwent a transformation into refined equiaxed crystals, carbides, and columnar crystals, replacing the coarsened columnar crystals and Laves phase present in IN718. Compared to IN718, the high-temperature tensile strength of CG-5 and CG-10 has increased by 80% and 180% at 900 ℃. Meanwhile, the mass gain due to oxidation per unit area of CG-5 and CG-10 has decreased by 23% and 11%, respectively. The results indicate that CG-10 exhibits a combination of highest high-temperature tensile strength and the enhanced resistance to high-temperature oxidation when compared to IN718 and CG-5.

Investigation of structural, optical, and electrical characterization of nanostructured Bi30Sb10Se60-based photodetector applications

This study thoroughly investigates the optical absorption properties of Bi30Sb10Se60 thin films, focusing on their applicability in photo-sensing technologies. By employing a range of spectrophotometric techniques, including transmission and reflection analyses, the research identifies a direct energy gap of 1.68 eV, along with dispersion and oscillator energies of 14.36 eV and 3.42 eV, respectively. These parameters reveal the material's interaction capabilities with light. The study highlights the heterojunction's pronounced photosensitivity, especially at lower reverse biases, indicating its promise for photo-sensing applications. Photoluminescence (PL) spectra show broad defect emission bands with peaks at 475 nm, 487 nm, 510 nm, and 525 nm, which provide insights into recombination processes. Additionally, Energy Dispersive Spectroscopy (EDS) confirms the films' near-stoichiometric composition, while Thermal Gravimetric Analysis (TGA) demonstrates the high thermal stability of the films. The findings include high responsivity and detectivity of the photodetector, though the linear dynamic range (LDR) and signal-to-noise ratio (SNR) are comparatively lower. Overall, the research advances the understanding of Bi30Sb10Se60 thin films, paving the way for their use in optimized photoresponsive devices within optoelectronic technologies.

A Review of Non-Powder-Bed Metal Additive Manufacturing: Techniques and Challenges.

Metal additive manufacturing has significantly evolved since the 1990s, achieving a market valuation of USD 6.36 billion in 2022, with an anticipated compound annual growth rate of 24.2% from 2023 to 2030. While powder-bed-based methods like powder bed fusion and binder jetting dominate the market due to their high accuracy and resolution, they face challenges such as lengthy build times, excessive costs, and safety concerns. Non-powder-bed-based techniques, including direct energy deposition, material extrusion, and sheet lamination, offer advantages such as larger build sizes and lower energy consumption but also encounter issues like residual stress and poor surface finish. The existing reviews of non-powder-bed-based metal additive manufacturing are restricted to one technical branch or one specific material. This survey investigates and analyzes each non-powder-bed-based technique in terms of its manufacturing method, materials, product quality, and summary for easy understanding and comparison. Innovative designs and research status are included.

Optical and gamma-ray shielding properties of calcium sodium borate glasses with varied equal concentrations of ZnO and BaO

This study presents the optical and radiation shielding characteristics of a newly developed borate glass, doped with equal quantities of ZnO and BaO, and modified with calcium and sodium. The glass samples were prepared using the melt quenching technique, with the composition formula (80-x-y)B2O3-10CaO-10Na2O-xZnO-yBaO, where x and y were varied at 5, 10, 15, and 20 mol%. Comprehensive analyses of the optical and gamma shielding properties were carried out using UV–visible spectrophotometry and Phy-X software, respectively. The UV–visible spectroscopic data allowed for the calculation of various parameters including the direct and indirect optical energy band gaps, refractive index, dielectric constants, and polarizability. It was observed that the direct optical energy band gap decreased from 3.91 to 3.10 eV, while the indirect band gap fell from 3.41 to 2.91 eV with increasing ZnO and BaO content. Conversely, the refractive index rose from 2.29 to 2.42 with higher concentrations of ZnO and BaO. The linear attenuation coefficients (LACs) across the range of 0.015–15 MeV exhibited an inverse relationship. Among the glass samples, B40Zn20Ba20 exhibited the lowest tenth value layer (TVL) and the highest effective atomic number (Zeff), indicating its superior performance as a radiation shielding material. Overall, the produced glass samples demonstrate commendable properties for both optical applications and radiation shielding.

Review of peer-to-peer energy trading: Advances and challenges

The power system is confronting progress due to the high integration of distributed energy resources (DERs). These DERs are expected to cause challenges for power system operations. Therefore, innovative management approaches were proposed for integrating DERs in future power systems and maximizing DER owners’ benefits, such as peer-to-peer (P2P) energy trading. Direct energy trading between users is made possible by P2P energy trading, which supports bulk power infrastructure operations while supporting local power and energy balance. P2P energy trading is a promising approach to expanding the installation of renewable energy sources and achieving the system flexibility required for the shift to low-carbon energy. The grid is anticipated to gain from P2P energy trading by having lower reserve requirements, peak demand, and network losses. Many studies and pilot projects have shown how P2P energy trading benefits prosumers as well as the grid. However, the widespread use of such trading models remains limited in today's electrical markets. This paper reviews recent advances in the P2P energy system and a perceptive discussion of the challenges that are keeping P2P from becoming a viable energy management solution in the present electrical market. First, the energy network is covered in this paper's description of these new P2P markets; next, the types of P2P energy trading, moving on to the market structure. Then, the technologies and technical approaches behind P2P energy trading are covered. After that, P2P energy trading advances in different systems are discussed. Finally, we identify challenges before making some concluding remarks.

Feasibility of manufacturing high-aspect-ratio hollow tubes of SS410 through wire-arc directed energy deposition

This study reports new observations from the fabrication of high-aspect-ratio hollow tubes of SS410 through wire-arc directed energy deposition (wire-arc DED) process. Characterisation work was performed on a single tube as a function of its build height. The maximum ultimate tensile strength (UTS) of 1372 MPa and maximum yield strength (YS) of 980 MPa were achieved in the middle region of the tube. The highest UTS in the middle was attributed to the low delta ferrite content. The reduction of delta ferrite was found to be linked with the repetitive heating and cooling. In contrast, the top and bottom sections exhibit a substantial presence of delta ferrite, indicating that the cyclic effects were not considerable. Nevertheless, the presence of significant ductility in the bottom region of the component indicated the occurrence of tempering effects. This observation is further supported by the lower levels of local strain observed using KAM mapping. Overall, this work proposes a novel fabrication method for producing hollow sections with superior strength and ductile properties.

Synthesis of MnO@Fe2O3 core-shell doped PVA/PVP polymeric nanocomposites for electronic and optoelectronic devices: Mechanical, electrical, and optical properties

Abstract The aqueous solution cast method was utilized to create biodegradable nanocomposite of polymers (PNC) films from a poly (vinyl alcohol) / poly (vinyl pyrrolidone) blend (70/30 wt%) and MnO@Fe2O3 nFs. The dislocation density, particle size, and interplanar distance were all calculated. The PNC films' surface shape changes from smooth to porous and somewhat rough because of the nanosized MnO@Fe2O3 particles' dispersion in the blend matrix, which diminishes the blended crystallites' size. The composite film's tensile strength increased from 9.45 MPa for the pure (PVA-PVP) film to 22.35 MPa due to the addition of 6 wt% MnO@ Fe2O3. The optical band gap decreases from 5.26 and 4.84 eV for pure (PVA/PVP) blend direct and indirect energy band gap to 5.18 and 4.71 eV for comparable values of 6wt% MnO@Fe2O3 nFs. Up to 6 wt% MnO@Fe2O3 concentration, PNC films' dielectric permittivity first declines, but it is substantially identical to the pure polymer blend matrix. The PNC sheet's dielectric permittivity increases nonlinearly with temperature, although its DC conductivity follows the Arrhenius law. Laser power was attenuated by (PVA- PVP)/MnO@Fe2O3 for both He-Ne and solid-state green laser beams. When the MnO@Fe2O3 concentration in the blend matrix rises to 6 wt%, the output power for lasers with 532 nm and 650 nm wavelengths drops from 5.49 to 2.4 mW and 19.8 to 9.4 mW, respectively. The findings suggest that nanocomposites exist and are widely recommended for optoelectronics, microelectronics, radiation detection, and several other uses.

Comprehensive analysis of Nd0.5Ba0.5CoO3 cobaltite: Unveiling electrical, optical and magnetic characteristics for optoelectronic applications

In this study, we successfully synthesized the perovskite cobaltite Nd0.5Ba0.5CoO3 (NBCO) using the sol-gel method and thoroughly characterized its optical and magnetic properties. Optical measurements, using UV absorption, the Tauc model, and diffuse reflectance spectroscopy (DRS), revealed multiple direct bandgap energies, with the most significant values being 5.23 eV (Tauc method), 5.1 eV (DRS), and 4.9 eV (reflectance). The high bandgap energies highlight NBCO's suitability for UV and optoelectronic applications. The refractive index varied between 2.48 and 3.55, while the Urbach energy was measured at 2.32 eV, indicating a moderate level of localized disorder. Magnetic characterization demonstrated a ferromagnetic-to-paramagnetic transition at 125 K, with strong molecular field effects influencing the exchange interactions. The dielectric analysis revealed an exceptionally low loss factor (tan δ ≈ 0.0012), underscoring NBCO's potential for efficient energy storage and electronic applications. These results show that NBCO offers a unique combination of high optical bandgaps, strong magnetic properties, and low dielectric loss, making it a promising candidate for advanced optoelectronic and magnetic devices.

A Novel 10-Watt-Level High-Power Microwave Rectifier with an Inverse Class-F Harmonic Network for Microwave Power Transmission

A novel 10-Watt-Level high-power microwave rectifier with an inverse Class-F harmonic network for microwave power transmission (MPT) is presented in this paper. The high-power microwave rectifier circuit comprises four sub-rectifier circuits, a 1 × 4 power divider, and a parallel-series dc synthesis network. The simple inverse Class-F harmonic control network serves dual roles: harmonic control and impedance matching. The 1 × 4 power divider increases the RF input power fourfold, reaching 40 dBm (10 W). The parallel-series dc synthesis network enhances the resistance to load variation. The high-power rectifier circuit is simulated, fabricated, and measured. The measurement results demonstrate that the rectifier circuit can reach a maximum RF input power of 10 W at 2.45 GHz, with a maximum rectifier efficiency of 61.1% and an output dc voltage of 23.9 V, which has a large application potential in MPT.

Laser-based directed energy deposition of Monel K-500 and Stellite 6 multi-materials

ABSTRACT Laser-based directed energy deposition (L-DED) offers significant advantages for repairing metal structures, particularly in the marine and offshore industry where corrosion-resistant materials like Monel K-500 (a Ni-Cu alloy) lack strength and wear resistance. This study addresses this issue by producing Monel K-500 with high-strength Stellite 6 (a Co-Cr alloy). Two types of multi-material samples were created using L-DED: interlayered and mixed powder samples. The interlayered samples experienced cracking at the material interface, while the mixed powder samples were crack-free and exhibited improved mechanical properties, with yield strength increasing from 208.3 MPa to 490.2 MPa and ultimate tensile strength from 429.7 MPa to 887.0 MPa compared to single Monel K-500 samples. This research demonstrated the potential of in-situ alloying during the L-DED process to enhance alloy properties and highlighted the challenges of abrupt compositional changes leading to cracking, suggesting mitigation strategies for successful production.

A Quasi-Isotropic Probe for High-Power Microwave Field Measurement.

In the paper, a new design of a quasi-isotropic antenna for high-power electromagnetic (EM) field measurement is presented, along with its investigation into suitability. The measuring probe is intended for assessing pulsed microwaves, which cannot be measured by available meters due to the high value of electric field strength and short pulse duration. The measurement of such a strong field is required according to guidelines for protecting people against microwave fields, especially those emitted by radars. The proposed probe is based on the concept of dipole-diode detection. To enable high-power measurement, the receiving antenna is electrically "small," allowing diode detection within the diode square-law characteristics range. Additionally, the shortened dipole length minimizes the spatial integration error, which can be significant in the case of microwave measurement. To obtain the desired antenna polarization, a new dipole geometry was proposed. Fulfilling the requirement of measuring all incident EM field polarizations, the receiving antenna was based on three dipoles arranged within a specific "magic" angular arrangement, ensuring a suitable quasi-isotropic radiation pattern. The proposed probe can operate in a frequency range from 1 GHz to 12 GHz.

Adjustable magnetic and wear properties of gradient Al–stainless steel materials fabricated by direct energy deposition

Adjustable magnetic and wear properties of gradient Al–stainless steel materials fabricated by direct energy deposition