Search Results (630)

Efficient monitoring of pork freshness is essential to minimize spoilage-related losses in the meat industry. To address the limitations of existing detection technologies, namely high cost, poor timeliness and high environmental sensitivity, this study developed a novel electronic nose system integrating a hybrid sensor array with dynamic gas path control. By combining metal oxide semiconductor (MOS) and electrochemical sensors (e.g., MQ137, MQ136), the system exhibits high sensitivity to the key volatile organic compounds (VOCs) released during pork spoilage, achieving a detection accuracy of over 90% in identifying spoilage stages. Combined with a dual-mode gas circuit design (solenoid valve switching time: 0.85 s), the reliability of the system was further demonstrated. This technology offers an economical and efficient real-time monitoring solution for slaughterhouses and cold chain logistics, providing a new low-cost scientific approach for pork freshness assessment. Full article

Black tea quality is governed by aroma chemistry: terpene alcohols (linalool, geraniol, nerolidol), methyl salicylate, and short-chain aldehydes whose abundance and release kinetics from the polyphenol-rich leaf matrix shape perceived grade. Grade information lies not only in the average headspace concentration but in the temporal shape of volatile organic compound (VOC) release under controlled heating. Conventional electronic noses obscure this signal: they rely on multi-sensor arrays, compress each response into summary statistics, and report accuracy only at the level of individual measurements. Whether a single low-cost metal–oxide–semiconductor (MOS) gas sensor can recover grade-defining aroma chemistry, and whether waveform-level modeling can exploit it, was therefore investigated. A portable electronic nose built around a Bosch BME688 sensor recorded 90 time series, each comprising four directly measured channels (temperature, humidity, pressure, gas sensor resistance) and a derived indoor-air-quality (IAQ) proxy computed from them by the on-chip BSEC library, from 16 commercial Turkish black teas across three quality grades. Two representations were compared on the same data: a feature-based pipeline reducing 25 statistical descriptors to seven principal components for six classifiers (best F1-macro = 0.624, MLP), and a raw-waveform Multi-Scale 1D-CNN with Squeeze–Excitation and temporal self-attention (MS-CNN-Attention). Under product-grouped cross-validation, the deep model reached F1-macro = 0.811 (+30%) and graded 14 of 16 products correctly by majority vote, against 11 of 16 for the MLP, with the largest gain in the medium grade (F1: 0.52 → 0.79), where summary-statistic compression destroys the release-kinetic signal. The contributions are threefold: one programmable MOS sensor operated as a thermal-desorption profiler rather than a sensor array; a direct comparison of feature-based classical learning against raw-waveform deep learning on the same small, non-normally distributed dataset; and a product-level decision-consistency metric suited to batch screening. Pairing a low-cost MOS sensor with waveform-level modeling offers a rapid, non-destructive route to aroma-chemistry-based tea quality screening. Full article

Pesticides are widely used chemical compounds in agriculture, but their presence in water systems represents a significant environmental and health problem. Due to their stability and toxicity, many pesticides are difficult to remove using conventional water treatment methods, which has led to the development of advanced oxidation processes. Photocatalytic processes are based on the activation of semiconductor materials under light irradiation, leading to the formation of reactive species that degrade pesticides into less harmful products. On the other hand, electrocatalytic processes use electrical energy to generate oxidation and reduction reactions on electrode surfaces, enabling efficient degradation of organic pollutants. Both approaches offer high efficiency and the potential for complete mineralization of pesticides. Nanomaterials play a key role in improving these processes, as they provide a large specific surface area, enhanced conductivity, and increased reactivity. In photocatalysis, nanostructured metal oxides such as TiO₂ and ZnO are commonly used, while in electrocatalysis, advanced nanocomposites and modified electrodes are applied to improve electron transfer efficiency and system stability. This review paper provides an overview of recent research in the field of photocatalytic and electrocatalytic systems for pesticide removal from water, with a particular focus on the role of nanomaterials. Special attention is given to current trends, including the development of new nanostructures, hybrid systems, and energy-efficient technologies. The aim of this paper is to present, in a simple and clear way, the potential of these methods and to contribute to a better understanding of their application in environmental protection. Full article

Low-frequency (LF, ν ≤ 200 cm⁻¹) vibrational modes of crystalline organic semiconductors are of particular interest because they significantly affect charge transport in these materials. Herein, we study LF vibrations of [1]benzothieno[3,2-b][1]benzothiophene (BTBT) substituted by phenyls, (per)fluorophenyls or pyridyls using the synergy of Raman spectroscopy and (periodic) DFT calculations. The LF spectra for the compounds with electron-withdrawing (fluorine or nitrogen) atoms differ significantly in the band positions and intensities from those for diphenyl-substituted BTBT, whereas the high-frequency (HF, ν > 200 cm⁻¹) spectra are quite similar for all the compounds studied, excluding the perfluorophenyl-substituted BTBT. We found that Ph-BTBT-Ph counterparts containing one electron-withdrawing atom per aryl ring show significantly lower LF Raman intensity compared to the parent compound. The LF intensity decrease is attributed to the suppression of intermolecular motions by the stronger electrostatic interactions. The unexpected LF intensity increase for the perfluorophenyl-substituted BTBT can be ascribed to strong dynamic disorder induced by easier torsion of phenyls with respect to the BTBT core, which also results in the deterioration of the π-conjugation revealed in the HF Raman spectra. We anticipate that the established structure–property relationships will contribute to the rational design of crystalline organic semiconductors towards controlled dynamic disorder and high charge mobility. Full article

This study investigates the pressure-dependent structural, electronic, mechanical, and thermoelectric properties of LiYN (Y = Sr, Mg, Zn) half-Heusler compounds using first-principles calculations. The structural stability was analyzed by fitting the total energy versus volume curves using the Birch–Murnaghan equation of state, allowing the determination of equilibrium lattice parameters and bulk moduli at pressures of 0, 5, and 10 GPa. Elastic constants were calculated to assess the mechanical stability, and all compounds satisfy the Born stability criteria over the entire pressure range. The Pugh ratio (B/G) and Poisson’s ratio (ν) indicate that LiSrN, LiMgN, and LiZnN exhibit predominantly brittle behavior under 0 GPa. Electronic band structure calculations reveal that LiMgN and LiZnN exhibit direct band gaps, whereas LiSrN shows an indirect band gap. Increasing pressure leads to a systematic widening of the band gaps due to lattice compression. Thermoelectric properties were evaluated using the Boltzmann transport theory within the constant relaxation time approximation. The Seebeck coefficient, electrical conductivity, and figure of merit (ZT) were found to be strongly dependent on both temperature and pressure. Notably, at 300 K, the ZT values increase from 0.005, 0.35, and 0.54 at 0 GPa to 0.027, 1.12, and 1.13 at 10 GPa for LiMgN, LiSrN, and LiZnN, respectively. These results demonstrate that hydrostatic pressure significantly enhances the thermoelectric performance of LiYN compounds, highlighting their promising potential for thermoelectric energy conversion applications. Full article

Clinical monitoring of chronic liver disease (CLD) is currently hindered by the invasiveness of conventional biopsies. While breath-borne volatile organic compound (VOC) analysis offers a promising non-invasive alternative, the metabolic profiles of sedentary populations often overlap significantly with those of healthy individuals, making latent pathologies difficult to identify. To overcome this high-resolution diagnostic challenge, this study developed an integrated framework that couples high-performance semiconductor sensing technology with a machine learning-based analytical baseline. During the biomarker screening phase, GC-MS was utilized to analyze over 2000 VOCs, identifying 20 markers associated with CLD. These were further optimized into a robust feature panel including ammonia, isoprene, dimethyl sulfide (DMS), and limonene. For several critical metabolic features exhibiting high diagnostic potential, preliminary identifications were conducted by referencing NIST database matches and relevant literature. To maintain analytical rigor and account for the inherent complexity of trace volatile metabolites in biological samples, these signals are treated as putative metabolic features and characterized by their retention times. Regarding hardware, an InN-based sensor with Pt-AlN surface modification was fabricated, achieving a limit of detection (LOD) for ammonia below 0.2 ppm. Crucially, while the InN sensor was validated for specific core markers such as ammonia, the current AI classification model is trained on a refined 7-VOC panel derived from the comprehensive GC-MS data. To resolve diagnostic overlaps, a three-state dynamic sampling protocol (resting, exercise, and recovery) was implemented to isolate biomarkers that remain physiologically stable. By integrating multi-dimensional VOC features (e.g., isoprene and DMS) with sensor-validated data through DBSCAN and Random Forest algorithms, the framework successfully captured non-linear metabolic fingerprints. Machine learning results confirm that the framework effectively distinguished sedentary controls from CLD patients, achieving a macro-average AUC of 0.96. This integration provides a high-precision technical pathway for early-stage liver disease screening. Full article

Digital twin technology is rapidly gaining traction in the semiconductor industry for its ability to model manufacturing processes, including packaging engineering, to monitor and optimise performance cost-effectively. This paper focuses on two key areas of development. The first part explores the potential of digital design and additive manufacturing to produce high-performance, compact thermal management solutions that significantly reduce device junction temperatures and enhance operational efficiency. The second part presents the development of surrogate models to predict junction temperatures of electronic packages under varying operating and geometrical conditions. These models, trained using deep learning, were integrated into a user-friendly COMSOL Multiphysics application builder version 6.3. The proposed digital twin framework enables fast and accurate full-thermal field predictions in comparison to conventional 3D finite element simulations. Full article

The need for sustainable and cost-effective thermoelectric materials has brought attention to earth-abundant and mineral compounds, like Cu₂ZnSnS₄ (CZTS). In this work, CZTS nanoparticles (NPs) were synthesized via the sol–gel method using environmentally friendly solvents based on water and ethanol mixtures. The resulting CZTS NPs were then processed into inks through ball milling to produce a thin-film thermoelectric generator (TEG). Structural and microstructural properties were investigated via X-ray diffraction and Raman spectroscopy, confirming the kesterite CZTS phase upon sintering. The chalcogenide exhibited p-type semiconductor behaviour, with a Seebeck coefficient reaching ~69 µV/K at 385 K. Van-der-Pauw measurements of conductivity confirmed a non-degenerate semiconducting behaviour, achieving ~1.77 S/cm at 323 K. A two-leg CZTS thin-film TEG reaching a maximum power output of 32(3) nW at a ΔT ~160 K was used, measured with a home-made setup. The volume-specific power of the generator reached $4\times {10}^{-4}$μW cm⁻³ K⁻². These results point to an effective use of sol–gel-based techniques to produce a functional thermoelectric generator, providing a costless and environmentally friendly approach to CZTS NPs. Full article

The structural, mechanical, electronic, and optical properties of cubic double perovskite oxides A₂TiSiO₆ (A = Ca, Sr, Ba) were systematically investigated using first-principles density functional theory calculations. Structural optimization within the GGA–PBE framework confirms that all compounds crystallize in a stable cubic phase. The negative formation energies indicate thermodynamic stability and potential experimental synthesizability. Ab initio molecular dynamics (AIMD) simulations performed at 300 K further confirm the dynamical stability of all compounds under finite-temperature conditions. The Born–Huang stability criteria performed elastic constant analysis establishes mechanical stability and the derived mechanical moduli indicate the presence of rigid but brittle behavior with moderate amounts of elastic anisotropy. Calculation of the electronic band structure reveals that all the compounds are direct wide-bandgap semiconductors, with the HSE06 bandgaps of Ca₂TiSiO₆, Sr₂TiSiO₆ as well as Ba₂TiSiO₆ being 2.61, 2.50 and 2.37 eV, respectively. The optical property analysis has shown that they are strong in terms of their absorption in the visible–ultraviolet region, with high dielectric constants and good refractive indices, which makes them appropriate in optoelectronics and photovoltaic applications. On the whole, A₂TiSiO₆ double perovskites are promising for use as wide-bandgap materials in the development of superior optoelectronic devices. Full article

Organic light-emitting diode (OLED)-based devices continue to grow rapidly in popularity. This work presents a comprehensive thermodynamic study of four nitrogen-containing organic semiconductors: 1,3-bis(9H-carbazol-9-yl)benzene (mCP), 1,3,5-tri(9H-carbazol-9-yl)benzene (TCB), 1,3,5-tris(diphenylamino)benzene (TDAB), and 1,3,5-tris[(3-methylphenyl)phenylamino]benzene (m-MTDAB). A self-consistent set of phase-change thermodynamic parameters in a wide temperature range was obtained using several independent experimental and computational techniques. Vapor pressure measurements above the liquid and crystalline phases of the compounds under study were carried out using the thermogravimetry–fast scanning calorimetry method. Based on the temperature dependence of the measured vapor pressures, vaporization and sublimation enthalpies were derived. Differential scanning calorimetry was employed to determine the heat capacities of the condensed phases and the melting parameters of the studied compounds, as well as to investigate the polymorphism of TCB. Solution calorimetry was used to determine the fusion enthalpies of the compounds at 298.15 K. The obtained values were additionally compared with the literature data and calculated estimates. The results of this study may be used to predict properties for compounds with similar molecular structures. Full article

Volatile organic compounds (VOCs) pose significant health risks. Photocatalytic oxidation offers a promising route for VOC purification under ambient conditions. Based on a review of over 80 studies, this article critically evaluates research progress on four semiconductor photocatalyst systems (TiO₂-based, g-C₃N₄-based, bismuth-based oxides, and MOFs) for VOC degradation. Unlike traditional descriptive reviews, this work establishes a quality-based filtering framework to distinguish studies reporting standardized photochemical parameters from those that do not. The analysis reveals a fundamental problem: the vast majority of reviewed studies lack essential parameters (incident photon flux, apparent quantum yield, or rigorous dark adsorption equilibrium), rendering cross-study comparisons invalid. Most literature relies on non-standardized metrics such as conversion percentages or rate constants per catalyst mass. While some high-quality studies report AQY, these remain a small fraction of the literature. Within individual studies under identical conditions, modification strategies enhance activity relative to controls, but relative efficiency (ζr) values are meaningful only within the same study and cannot be compared across setups. This review thus serves a dual purpose: to summarize modification strategies and to critically expose the lack of standardization. Future research must adopt unified reporting standards (photon flux, AQY, benchmarks under identical conditions) to transform the field into a reproducible, cumulative science. Full article

Perylene bisimide derivatives are typical n-type semiconductors as well as redox-active materials. However, it has been difficult to produce thin films by solution processes because of their low solubilities in organic solvents. Perylene bisimide derivatives bearing oligosiloxane moieties exhibit columnar phases over wide temperature ranges, including room temperature and high solubilities in organic solvents. The columnar phases are stabilized by nanosegregation between crystal-like one-dimensional π-stacks and liquid-like mantle consisting of oligosiloxane moieties. The electron mobility at room temperature exceeded 0.1 cm²V⁻¹s⁻¹ in the ordered columnar phases of perylene bisimide derivatives bearing four disiloxane chains. Uniaxially aligned thin films of the perylene bisimide derivatives bearing oligosiloxane moieties could be produced by a spin-coating method. The spin-coated films of the perylene bisimide derivatives bearing cyclotetrasiloxane rings could be insolubilized via in situ ring-opening polymerization by the exposure of the thin films to trifluoromethanesulfonic acid vapors. Uniaxially aligned thin films of perylene bisimide derivatives bearing an ethylene oxide chain as well as cyclotetrasiloxane rings could be doped in an aqueous solution of sodium dithionate, resulting in an anisotropic electrical conductivity. Polymerized thin films of perylene bisimide derivatives bearing a crown ether ring exhibited electrochromism in electrolyte solutions. These compounds formed 1:1 complexes with lithium triflate, exhibiting columnar phases at room temperature. The nanostructures of the complexes were stabilized by the electrostatic interaction between cationic crown-metal units and triflate anions. Full article

One-dimensional hybrid organic–inorganic semiconductors enable band-edge engineering through reduced dimensionality and interfacial orbital hybridization. Nevertheless, the electronic physics of Cu/Ag-based systems has received limited attention. Here, we perform high-throughput first-principles calculations on 90 Cu/Ag halide HOISs derived from experimentally reported parent structures to elucidate bonding-dependent electronic behavior. We uncover a clear transition from electronically isolated inorganic chains in ionic hybrids to strongly hybridized band edges in covalent and mixed-bonding hybrid frameworks, where ligand p orbitals cooperatively couple with Cu-derived states and halogen p orbitals. This hybridization produces p-orbital-dominated band edges, enhanced dispersion, and light-hole effective masses along the 1D chains. Guided by this bonding-driven mechanism, we further identify four Cu-based compounds, which are helpful for tuning light-harvesting properties in low-dimensional hybrid semiconductors. Full article

This paper systematically studied the structural, mechanical, electronic, and optical characteristics of cubic KZnX₃ (X = F, Cl, Br, and I) perovskites through the density functional theory (DFT) in the Quantum Espresso framework. Structural optimization and stability analyses confirm that all compounds crystallize in the cubic Pm-3m phase and are thermodynamically, mechanically, and dynamically stable. Elastic constants indicate that the materials are anisotropic and ductile in nature. Calculations of Debye temperatures show a systematic decrease of 402 K (KZnF₃) to 158 K (KZnI₃), which is related to the increasing mass of halogen and its impact on the rigidity of the lattice. Electronic structure calculations show that all compounds are indirect bandgap semiconductors, with bandgaps systematically decreasing from 4.24 eV (KZnF₃) to 0.86 eV (KZnI₃) at the HSE06 level, enabling tunable semiconducting characteristics for optoelectronic applications. The analysis of the density of states and charge density indicates that the bonding between Zn and X is mixed ionic and covalent and that the bonding between K and X is mostly ionic. Calculations of optical properties show an increase in polarizability, absorption, refractive index and plasmonic response when heavier halogen is used, highlighting the potential of KZnX₃ perovskites for photovoltaic and optoelectronic devices. Overall, halogen substitution in KZnX₃ provides an effective strategy for tailoring electronic and optical properties. Full article

Employing ab initio electronic structure methods, in this study, I examine the effect of order on the spin gapless semiconducting behavior of the Mn₂CoAl Heusler compound. The occurrence of atomic disorder in general destroys the spin gapless semiconductivity observed in the inverse XA lattice structure; however, in some cases, novel magnetic configurations emerge. In the case of structures derived from the XA structure, where only Mn-Co or Mn-Al atoms are mixed, Mn₂CoAl alloy presents a half-metallic magnetic character. In the case of full disorder (A2 lattice structure), where atoms occupy all sites with the same probability, the ground state is an antiferromagnetic metallic one. The L2₁ and B2 lattice structures, where Mn atoms occupy both sites of a similar local environment, correspond to a ferromagnetic state of very high spin magnetic moment per formula unit. The present study encompasses a much larger variety of disordered structures in comparison with other studies in the literature. It concludes that the control and minimization of the concentration of impurities at anti-sites is imperative to achieving optimal performance in spintronic devices based on spin gapless semiconducting Mn₂CoAl. Full article