Search Results (102)

Many engineering design problems are formulated as constrained optimization tasks that are nonlinear and nonconvex, and often treated as black boxes. In such cases, metaheuristic algorithms are attractive because they can search complex design spaces without requiring gradient information. In this work, we propose an Enhanced Henry Gas Solubility Optimization (eHGSO) algorithm, which is an improved version of the physics-inspired HGSO method. The enhanced variant introduces six main contributions: (i) a more diverse, population-wide initialization strategy to cover the design space more thoroughly; (ii) adaptive temperature/pressure control parameters that automatically shift the search from global exploration to local refinement; (iii) an elitist archive with differential perturbation that accelerates exploitation around high-quality candidate designs; (iv) a simple combination of the global HGSO search moves with a lightweight gradient-free local search to refine promising solutions; (v) a constraint-handling mechanism that explicitly prioritizes feasible solutions while still allowing exploration near the constraint boundaries; and (vi) a complexity and ablation analysis that quantifies the impact of each mechanism and confirms that they introduce only modest computational overhead. We evaluate eHGSO on four classical constrained engineering design problems: the stepped cantilever beam, the tension/compression spring, the welded beam, and the three-bar truss. Its performance is compared with seventeen recent metaheuristic optimizers over multiple independent runs. eHGSO achieves the best average objective value on the cantilever, spring, and welded-beam problems and shares the best average result on the three-bar truss. Compared to the second-best method, the mean objective is improved by about $0.84\%$ for the cantilever beam and $0.35\%$ for the welded beam, while the spring and truss results are essentially equivalent at four significant figures. Convergence and robustness analyses show that eHGSO reaches high-quality solutions quickly and consistently. Overall, the proposed eHGSO algorithm appears to be a competitive and practical tool for constrained engineering design problems. Full article

Persistent forest fire refugia are areas within fire-prone landscapes that remain fire-free over long periods of time and are crucial for ecosystem resilience. Modelling to develop maps of these refugia is key to informing fire and land use management. We predict persistent forest fire refugia using variables linked to the fire triangle (aspect, slope, elevation, topographic wetness, convergence and roughness, solar irradiation, temperature, surface wind direction, and speed) in machine learning algorithms (Random Forest, XGBoost; two ensemble models) and K-Nearest Neighbour. All models were run with and without ADASYN over-sampling and grid search hyperparameterisation. Six iterations were run per algorithm to assess the impact of omitting variables. Aspect is twice as influential as any other variable across all models. Solar radiation and surface wind direction are also highlighted, although the order of importance differs between algorithms. The predominant importance of aspect relates to solar radiation received by sun-facing slopes and resultant heat and moisture balances and, in this study area, the predominant fire wind direction. Ensemble models consistently produced the most accurate results. The findings highlight the importance of topographic and microclimatic variables in persistent forest fire refugia prediction, with ensemble machine learning providing reliable forecasting frameworks. Full article

Phase change materials (PCMs) integrated into building envelopes can store and release latent heat, reducing indoor temperature fluctuations and shifting thermal peaks. This study quantifies the time lag and comfort impact of PCM plaster under free-running conditions using two identical, instrumented model houses in Bácsalmás, Hungary. One house served as a reference, while the other was retrofitted with interior PCM plaster panels on four walls (51.2 kg paraffin, ≈8.12 MJ latent heat capacity). The temperatures of the walls, indoor air, and outdoor environment were monitored every five minutes for 105 spring/summer days. Daily peak times were extracted using moving-average smoothing, and time lags between exterior and interior wall peaks were computed. The PCM house exhibited roughly double the average lag compared with the reference (≈200 vs. ≈100 min), with lag distributions well described by lognormal fits. Comfort evaluation based on exceeded degree-hours (EDH) relative to the adaptive comfort range (EN 16798-1) revealed that larger peak-time lags correlated with lower overheating. Results confirm that PCM plaster significantly delays and attenuates daily temperature peaks, extends comfort periods, and supports passive strategies such as night ventilation and demand-side load shifting in lightweight buildings. Full article

In this study, non-isothermal pyrolysis of a mixture of disposable surgical face masks (FMs) and nitrile gloves (NGs) was conducted, using a heating rate of 100 °C/min, N₂ flowrate of 100 mL/min, and temperatures between 500 and 800 °C. Condensable product yield peaked at 600 °C (76.9 wt.%), with gas yields rising to 31.0 wt.%, at 800 °C. GC-MS of the condensable product confirmed the presence of aliphatic compounds (>90%), while hydrogen, methane, and ethylene dominated the gas composition. At 600 °C, gasoline (C₄ to C₁₂)-, diesel (C₁₃ to C₂₀)-, motor oil (C₂₁ to C₃₅)-, and heavy hydrocarbon (C₃₅₊)-range compounds accounted for 23.7, 46.7, 12.5, and 17.1%, of the condensable product, respectively. Using model-free methods, the average activation energy and pre-exponential factor were found to be 309.7 ± 2.4 kJ/mol and 2.5 ± 3.4 × 10²⁵ s⁻¹, respectively, while a 2-dimensional diffusion mechanism was determined. Scale-up runs confirmed high yields of condensable product (60–70%), with comparable composition to that obtained from lab-scale tests. The pyrolysis oil exceeds acceptable oxygen, nitrogen, chlorine, and fluorine levels for industrial steam crackers—needing pre-treatment—while other contaminants like sulphur and metals could be managed through mild blending. In summary, this work offers a sustainable approach to address the environmental concerns surrounding disposable FMs and NGs. Full article

Gallium Arsenide (GaAs) Schottky technology stands out for its superior performance in terms of conversion loss for terahertz mixers at room temperatures, which establishes it as a dominant solution in receivers for high-data-rate wireless communications. However, Indium Gallium Arsenide (InGaAs) Schottky mixers offer a notable advantage in terms of reduced power requirements due to their lower barrier height, enabling optical pumping with the incorporation of photodiodes acting as photonic local oscillators (LOs). In this study, we present the first comparative analysis of GaAs and InGaAs diode technologies under both electrical and optical pumping, which are also being compared for the first time, particularly in the context of a wireless communication system, transmitting up to 80 Gbps at 0.3 THz using 16-quadrature amplitude modulation (QAM). The terahertz transmitter and the optical receiver’s LO are based on modified uni-traveling-carrier photodiodes (MUTC-PDs) driven by free-running lasers. The investigation covers a total of two mixers, including narrow-band GaAs and InGaAs. The results reveal that, despite InGaAs mixers exhibiting higher conversion loss, the bit error rate (BER) can be as low as that with GaAs. This is attributed to the purity of optically generated LO signals in the receiver. This work positions InGaAs Schottky technology as a compelling candidate for terahertz reception in the context of optical wireless communication systems. Full article

β-glucuronidase is an important hydrolase, which plays an important role in drug metabolism, clinical diagnostics, and biotransformation. This study focuses on the heterologous expression, isolation, purification, and its enzymatic properties of β-glucuronidase CpGUS from Clostridium perfringens, as well as its application in the whole-cell transformation of unconjugated bilirubin from pig bile. A recombinant E. coli BL21(DE3)/pET-28a-CpGUS was constructed for the heterologous expression of CpGUS, with the majority of the expressed enzyme being soluble. Enzymatic analysis showed that CpGUS displayed optimal activity at pH 5.0 and 45 °C, and it rapidly lost activity at pH < 4.5. Metal ions, such as Mg²⁺ and Fe²⁺, enhanced CpGUS catalysis, while Zn²⁺, K⁺, Fe³⁺, Mn²⁺, Cu²⁺, and Na⁺ inhibited it. Notably, Cu²⁺ and Fe³⁺ can significantly inhibit β-glucuronidase, resulting in the complete loss of its activity. The results of the whole-cell transformation experiment show that when E.coli BL21(DE3)/ pET-28a-CpGUS at an OD₆₀₀ of 10 was incubated at pH 5.0, a temperature of 45 °C, and a rotation speed of 200 rpm for 12 h, the hydrolysis rate of the conjugated bilirubin in pig bile reached 81.1%, the yield of unconjugated bilirubin was 76.8%, and the purity of unconjugated bilirubin was 98.2%. The three-dimensional structure of CpGUS was predicted using AlphaFold2 (AlphaFold v2.0, DeepMind Technologise Limited, London, UK), and p-Nitrophenyl-β-D-Glucuronide (pNPG) and conjugated bilirubin were then docked to the CpGUS protein model using SWISSDOCK. The best docked conformations of the CpGUS–pNPG and CpGUS–conjugated bilirubin complex systems were simulated by independent 500 ns molecular dynamics (MD) runs with the RSFF2C force field, and the binding dynamic and catalytic mechanism of each system were obtained. The results indicated that π-π stacking, hydrogen bonding, and hydrophobic interactions between the key residue Tyr472 and the benzene ring of pNPG molecules are crucial for its catalytic process. Similarly, for the binding and catalysis of conjugated bilirubin by CpGUS, the π-π stacking and hydrogen bonding and hydrophobic interactions between the sidechains of residues Phe368 and Tyr472 and the benzene ring of conjugated bilirubin play a synergistic role during its catalytic process. Their total binding free energy (∆G_bind) values were calculated to be as high as −65.05 ± 12.66 and −86.70 ± 17.18 kJ/mol, respectively. These results suggest that CpGUS possesses high binding and catalytic hydrolysis properties for both pNPG and conjugated bilirubin. Full article

Submicron particles are widely used in industrial applications due to their unique physical and mechanical properties that enhance the performance of composite materials. In particular, boron carbide particles are valued for their exceptional hardness and high wear resistance and are especially valuable in protective coatings and aerospace applications. However, these particles can agglomerate, significantly impairing their effectiveness. When this occurs during the development of composite materials, physical and mechanical properties are negatively affected. In this paper, a chemical-free method using a non-destructive, open-system dry mechanical deagglomeration technique is developed, leaving the primary particles unaltered, while breaking up strong adhesions between primary particles resulting from the manufacturing process. This method was tested for the deagglomeration of as-received boron carbide submicron particles, with an average primary particle diameter of d₅₀ = 300 nm, and its effect on particle size distribution is presented. Furthermore, X-ray diffraction and true density measurements were carried out on the raw powder. Submicron particles in the dry and as-received state were poured into an experimental mold without a dispersing agent or a protective atmosphere. Static pressure was applied up to 141 MPa to produce tablets at room temperature, finding that 70 MPa yielded the best results in terms of homogeneity, dispersibility, and reproducibility. In order to break apart the densified pressed tablets, ultrasonication was applied before running particle size measurements in the wet dispersed state. Using a tri-laser diffraction light scattering technique, it was determined that particle size distribution followed a Gaussian curve, indicating that this method is suitable to regain the primary submicron particles with uniform properties. It is also shown that applying ultrasound on the as-received powder alone failed to cause the complete deagglomeration of strongly adhering primary particles. These findings suggest that there is no significant wear on the primary particles and no alteration of their surface chemistry, due to the lack of any chemically supported mechanisms such as the alteration of surface charge or the adsorption of surfactants. Furthermore, as the static pressure exerts an immediate impact on all particles in the mold, there is a clear economical advantage in terms of a shorter processing time over other deagglomeration methods such as high shear mixing. Full article

In this study, a quantitative profiling method for detecting free fatty acids in crude lanolin based on the Quality by Design (QbD) concept was developed. High-performance liquid chromatography (HPLC) equipped with a charged aerosol detector (CAD) and a Proshell 120 EC C18 column was employed for the separation of crude lanolin components. Initially, the analytical target profile and critical method attributes were defined. Potential critical method parameters, including column temperature, flow rate, isocratic run time, gradient end organic phase ratio, and gradient time, were identified using fishbone diagrams and single-factor experiments. The definitive screening design (DSD) was then utilized to screen and optimize these parameters. Stepwise regression was applied to establish quantitative models between the critical method attributes and the method parameters. Subsequently, the method operable design region (MODR) was calculated and was successfully verified. The analytical conditions established were configured with 0.1% formic acid in water and 0.1% formic acid in acetonitrile serving as the mobile phases. The flow rate was set at 0.8 mL/min, and the column temperature was maintained at 35 °C with the evaporation tube temperature also set at 35 °C. An injection volume of 10 μL was used for each analysis. The gradient elution conditions were as follows: from 0 to 30 min, 75% of solvent B was used, and from 30 to 60 min, the proportion of solvent B was increased from 75% to 79%. Ten components, including 12-hydroxystearic acid, 2-hexyldecanoic acid, and palmitic acid, were identified by mass spectrometry, and seven common peaks were found in the fingerprints. The contents of palmitic acid, oleic acid, and stearic acid in the crude lanolin were quantitatively determined. Both the fingerprint and quantitative analysis methods were validated. The method was applied to analyze 15 batches of crude lanolin from different sources. The new established quantitative profiling method for free fatty acids can be potentially used for industrial applications to enhance the quality control of crude lanolin. Full article

This study examined the grazing pressure and interactions between four species of wild kangaroos (Red Kangaroo Osphranter rufus, Common Wallaroo O. robustus, Eastern Grey Kangaroo Macropus giganteus, Western Grey Kangaroo M. fuliginosus), free-ranging feral goats (Capra hircus) and European rabbits (Oryctolagus cuniculus), and stocked Merino sheep (Ovis aries). The study site comprised two contiguous pairs of stocked and unstocked paddocks, one a sloping run-off zone, the other a flat run-on zone, covering a total area of 2158 ha. These paddocks on Fowlers Gap Station in far north-western New South Wales, Australia, are representative of the arid chenopod (Family: Chenopodiaceae) shrublands stocked with sheep. Sheep and red kangaroos dominate the mammalian herbivores by biomass. The study examined the relative grazing pressure exerted by the seven species of mammalian herbivores in stocked and unstocked conditions, where only sheep were confined, across a three-year period that included rain-deficient (drought) months. The effects of climate (especially rainfall and temperature) and herbivore density on the standing biomass of pasture were teased out at a macro-scale. Herbivory at a micro-scale was examined using open and exclosed plots with detection of herbivore species by fecal deposition and time-lapse videography. Sheep exerted the highest grazing pressure and there was no compensatory increase in grazing pressure by other herbivores in unstocked paddocks. Rainfall was a key driver of pasture biomass and condition and loss by senescence typically outweighed grazing pressure. Grazing effects at a micro-scale were plot-specific and complex. The results are discussed in relation to the sustainable management of rangelands for production and wildlife. Full article

The diamondback moth, Plutella xylostella, is arguably the most economically impactful and widespread lepidopteran pest. Though the larval P. xylostella life stage is responsible for most of this cost through the consumption of crops, it is the adult form that spreads the pest to fresh crops all around the world, seeking them out in a seasonally expanding range. It is therefore important to understand the activity rhythms of adult P. xylostella in response to environmental cues such as light and temperature. We analysed diel rhythms in both adult clock gene expression and locomotor behaviour for the ROTH P. xylostella strain. Real-time quantitative PCR analyses of P. xylostella demonstrated diel rhythms for transcripts of the clock genes period and timeless under both entrained and free-running conditions indicating the presence of a functional daily timekeeping mechanism. However, adult locomotor rhythms exhibited temperature-driven and light-repressed regulation rather than circadian control. Thus, our analyses show a lack of coupling between the P. xylostella circadian clock and adult locomotor behaviour, which may be relevant in predicting the activity patterns of this agricultural pest. Full article

As people spend the majority of their time indoors, maintaining a comfortable and suitable thermal environment within buildings is essential for improving quality of life. Previous studies in Japan have investigated the wet-bulb globe temperature (WBGT) in indoor environments; however, studies primarily focused on residential buildings are lacking. Therefore, a field survey of 17 Japanese dwellings was carried out during the summer, for which a total of 1166 thermal sensation votes (TSVs) were collected from 23 respondents. The results show that the average indoor air temperature is 26.4 °C, which is 1.6 °C lower than the recommendation for summer temperature by the Japanese government. The variation in globe temperature and WBGT indicates that there are significant differences in cooling usage behavior, with a strong correlation between WBGT and indoor globe temperature. The acceptable indoor globe temperature exhibits a wider range in free-running (FR) mode than in cooling (CL) mode. The mean comfort temperature was 26.9 °C in FR mode, while it was 27.0 °C in CL mode. These findings indicate that the occupants felt comfortable at the high indoor temperature, suggesting there is a possibility to reduce the energy used for cooling. Full article

Cu-containing and Ce-modified OMS-2 catalysts were prepared at various calcination temperatures using the hydrothermal method and tested for low-temperature CO oxidation. The structure, chemical compositions, and physical–chemical properties of the catalysts were characterized using XRD, N₂ physisorption, XRF, Raman spectroscopy, SEM, high-resolution TEM with EDX, TPR-H₂, and XPS. The incorporation of Cu into the Ce-OMS-2 sample facilitated the transformation of pyrolusite into cryptomelane, as confirmed by Raman spectroscopy data. In the light-off mode, the Cu/Ce-OMS-2-300 and Cu/OMS-2 samples exhibited higher activity in low-temperature CO oxidation (T₉₀ = 115 and 121 °C, respectively) compared to sample Cu/Ce-OMS-2-450. After a long-run stability test, the Cu/Ce-OMS-X samples demonstrated excellent performance: the T₈₀ increased by 16% and 7% for the samples calcined at 300 °C and 450 °C, respectively, while the T₈₀ for the Cu/OMS-2 increased by 40%. The Cu/OMS-2 and Cu/Ce-OMS-2-300 samples were found to have an increased content of nanodispersed copper sites on their surfaces. These copper sites contributed to the formation of the Cu²⁺-O-Mn⁴⁺ interface, which is responsible for the CO oxidation. The presence of Ce³⁺ in the catalyst was found to increase its stability in the presence of water vapor due to the higher reoxidation ability in comparison with Ce-free sample Cu/OMS-2. Full article

We experimentally investigate the dynamics characteristics of a two-state quantum dot laser (TSQDL) subject to optical feedback. Firstly, we inspect the impact of the temperature on the power-current characteristics of the ground state (GS) lasing and the excited state (ES) lasing in the TSQDL operating at free-running. The results demonstrate that with the decrease in the temperature, the threshold current for GS lasing ($I_{th}^{GS}$) and the threshold current for ES lasing ($I_{th}^{ES}$) decrease very slowly. There exists a current for GS quenching ($I_Q^{GS}$), which is gradually increased with the decrease in the temperature. After introducing optical feedback, the overall trend of change is similar to those obtained under free-running. Next, through inspecting the time series and power spectrum of the output from the TSQDL under optical feedback, the dynamical characteristics of the TSQDL are investigated under different feedback ratios, and diverse dynamical states including quasi-chaos pulse package, chaos state, regular pulse package, quasi-period two, quasi-regular pulsing, and chaos regular pulse package have been observed. Finally, for the TSQDL biased at three different cases: lower than $I_{th}^{ES}$, slightly higher than $I_{th}^{ES}$, and higher than $I_{th}^{ES}$, nonlinear dynamic state evolutions with the increase in feedback ratio are inspected, respectively. The results show that, for the TSQDL biased at lower than $I_{th}^{ES}$, it presents an evolution route of stable state—quasi-chaos pulse package—chaos state—regular pulse package. For the TSQDL biased at slightly larger than $I_{th}^{ES}$, it presents an evolution route of stable state—quasi-regular pulsing—quasi-period two—chaos regular pulse package. For the TSQDL biased at higher than $I_{th}^{ES}$, the TSQDL always behaves stable state within the range of feedback ratio that the experiment can achieve. However, with the increase in optical feedback ratio, the number of longitudinal modes for GS lasing and ES lasing are changed. Full article

Fructose is a carbohydrate with essential applications in the food industry, mainly due to its high sweetness and low cost. The present investigation focused on optimising fructose production from commercial inulin using the enzymatic immobilisation method and applying the response surface methodology in a 12-run central composite design. The independent variables evaluated were the pH (−) and temperature (°C). The substrate consisted of a commercial inulin solution at a concentration of 1 g/L, while the catalyst consisted of the enzyme inulinase from Aspergillus niger (EC 232-802-3), immobilised in 2% m/v sodium alginate. A stirred vessel reactor was used for 90 min at 120 rpm, and quantification of reducing sugars was determined using DNS colorimetric and UV–Vis spectrophotometric methods at a 540 nm wavelength. After applying the response surface methodology, it was determined that the catalytic activity using the immobilisation method allows for a maximum total productivity of 16.4 mg/h under pH and temperature of 3.9 and 37 °C, respectively, with an efficiency of 96.4%. The immobilised enzymes’ reusability and stability compared to free enzymes were evaluated, obtaining activity up to the fifth reuse cycle and showing significant advantages over the free catalyst. Full article

Molten slag has different properties depending on its composition. The relationship between its composition, structure, and properties has been the focus of attention in industrial manufacturing processes. This review describes the atomistic scale mechanisms by which oxides of different compositions affect the properties and structure of slag, and depicts the current state of research in the atomic simulation of molten slag. At present, the research on the macroscopic properties of molten slag mainly focuses on viscosity, free-running temperature, melting point, and desulphurization capacity. Regulating the composition has become the most direct and effective way to control slag properties. Analysis of the microevolution mechanism is the fundamental way to grasp the macroscopic properties. The microstructural evolution mechanism, especially at the atomic and nanoscale of molten slag, is reviewed from three aspects: basic oxides, acidic oxides, and amphoteric oxides. The evolution of macroscopic properties is analyzed in depth through the evolution of the atomic structure. Resolution of the macroscopic properties of molten slag by the atomic structure plays a crucial role in the development of fundamental theories of physicochemistry. Full article