Search Results (8,399)

Modern logistics and manufacturing environments simultaneously demand mobility platforms that are compact enough to navigate narrow aisles and powerful enough to transport oversized or heavy components. We previously developed a compact Steering–Drive–Suspension (SDS) module that integrates steering, in-wheel drive, and suspension within a single wheel envelope, achieving $\pm {90}^{\circ }$ wide-angle steering with a single actuator. The present paper extends that hardware-centric work by treating the two-wheel (2WD) configuration assembled from two SDS modules as the unit module of the platform, building a four-wheel (4WD) operation by coupling two such 2WD units, and developing a unified balance and impedance-based control scheme. We derive a cart–pole inverted-pendulum model for the 2WD configuration and a planar 2-DOF bicycle model for the coupled and cooperative configurations, with full controllability proof and quantitative LQR robustness margins. Three Python 3.12 based scenarios validate the framework: (i) a 2WD inverted-pendulum tracking task, (ii) a forward and lateral relocation maneuver compared across SDS Crab, Ackermann, and four-wheel-steering modes, and (iii) cooperative transport of a $100\mathrm{kg}$ steel plate by two impedance-coupled 2WD units. Across all scenarios the proposed controllers achieve sub-centimetre tracking gap, pitch deviation within $\pm 2^{\circ }$, and well-damped cooperative behavior without payload sloshing. The results substantiate the central design claim that the SDS module’s compactness enables a single hardware platform to act simultaneously as an autonomous small-payload mover, a building block of a 4WD platform, and a cooperative agent for oversized loads. Full article

Biokinetic complexities (plastic sorption, protein binding, and cellular accumulation) may cause large discrepancies between nominal and biologically effective concentrations of test compounds assessed by new approach methods (NAMs). This case study was performed to explore a generally applicable workflow that addresses biokinetic complexities in the context of NAM-based hazard testing for next-generation risk assessment (NGRA). The pesticide tebufenpyrad (TEBU) is a challenging test compound, as it (i) is hydrophobic, (ii) has an intracellular target (mitochondrial respiration), and (iii) is acting at low concentrations (susceptible to biokinetic complexities). In the newly established NeuriTox-M neurotoxicity assay, based on human dopaminergic (LUHMES) neuron cultures, TEBU showed toxic effects at 20 nM. Mass spectrometric analyses of various experimental setups showed that a large fraction (75% to >90%) of TEBU was adsorbed to plastic. This effect was strongly attenuated by albumin in the medium. Cells, cultured on plastic, were considered unsuitable to assess cellular uptake. Therefore, alternatives were explored: when cells were used as suspension cultures (3% v/v) in albumin-containing medium, analysis worked best. Under such conditions, the concentration ratio (cells/medium) of TEBU was around 10. Data from an in vitro distribution (VIVD) model were in good agreement with the measurements. VIVD predicted the unbound medium TEBU concentration (C_u) to be 2–3 orders of magnitude below the nominal concentration and the total cellular concentration to be 10–100-fold above. Standard cell culture assays showed that the medium albumin content indeed altered the TEBU toxicity threshold. More such studies are needed to embed biokinetics information into NGRA. Full article

Orchid plants, due to their high aesthetic qualities of large inflorescences, long flowering period, and ease of care, have high commercial potential; however, when grown industrially in factories, they are susceptible to infectious diseases. In this study, we isolated from Phalaenopsis spp. plants epiphytic, rhizospheric, and endophytic bacteria associated with soft rot symptoms. Twenty-nine isolates exhibiting pectolytic activity were identified as strains of the genera Bacillus, Klebsiella, Microbacterium, Paenibacillus, Paracidovorax, Pseudomonas, and Psychrobacillus based on 16S rRNA analysis. These isolates were tested for their ability to produce cellulase, amylase, sucrase, proteinase, and lipase; to form biofilms; and to exhibit motility (swimming and swarming). Potato microplants under in vitro conditions were used as a model object for initial screening of the strains’ potential phytotoxicity. Most strains were shown to inhibit plant growth, particularly root development. Injection of suspensions of these strains into orchid leaves caused symptoms of soft rot. Thus, we isolated Gram-positive bacteria for the first time from orchid tissues with soft rot symptoms and demonstrated an association of these strains with plant tissue maceration in potato and orchids. Gram-positive bacteria with pectolytic activity are not typical pathogens of orchid soft rot and may require changes in approaches to the monitoring of phytopathogens for this group of plants. Full article

This study provides strong evidence of structural asymmetries between religious and non-religious tourism demand in Saudi Arabia over the period 2015Q1–2024Q4. The unit root results indicate that all variables are integrated of order one, supporting the application of the ARDL framework. The bounds test confirms the existence of a long-run equilibrium relationship for both religious and non-religious tourism. However, the strength and determinants of these relationships differ across tourism segments, providing evidence of structural heterogeneity in tourism demand. The empirical findings show that global oil prices do not have a statistically significant direct effect on either tourism segment in both the short run and the long run, suggesting that their influence is indirect and transmitted through broader macroeconomic channels. In contrast, non-oil GDP exerts a positive effect on non-religious tourism and remains weakly significant in the long run, highlighting the critical role of economic diversification and sustained income growth under Vision 2030. Religious tourism, however, remains largely unaffected by economic growth, reflecting its institutional and policy-driven nature. The COVID-19 pandemic had a severe and persistent negative impact on tourism demand, with a more immediate and pronounced effect on religious tourism due to the suspension of Hajj and Umrah activities. Adjustment dynamics indicate that both tourism segments converge toward their long-run equilibrium following short-run shocks, although religious tourism exhibits a somewhat faster speed of adjustment. Diagnostic tests confirm that all econometric assumptions are satisfied, supporting the robustness and reliability of the results. Full article

To address the uneven distribution of secondary-suspension loads, the insufficient prediction accuracy of conventional mechanistic models, and the limited comprehensive optimization capability of existing leveling algorithms in the weighing and leveling process of high-speed railway carbodies, this study proposes a secondary-suspension load distribution optimization method that integrates radial basis function (RBF) neural-network error compensation with a multi-objective improved whale migration optimization algorithm. First, a mechanistic model describing the relationship between secondary-suspension loads and shim thickness is established based on the four-point weighing mechanics, and an RBF neural network is employed to compensate for the model prediction error, thereby improving the characterization accuracy of the actual loading state of the carbody. Second, a multi-objective optimization model for carbody weighing and leveling is formulated by taking the load standard deviation, total shim thickness, and number of shim positions as optimization objectives. Furthermore, the whale migration algorithm is improved according to the requirements of secondary-suspension load optimization, enabling collaborative multi-objective optimization of load deviation and total shim thickness. Finally, simulated-carbody tests and field tests on actual carbodies are carried out using a weighing and leveling test bench. The results show that the proposed method can identify the stress-free state of the carbody more accurately, reduce the error between theoretical calculations and measured data, and effectively improve the nonuniform distribution of secondary-suspension loads, demonstrating good engineering applicability. Full article

Zeolite morphology strongly determines its performance. Herein, Silicalite-1 was synthesized in a low-template system (TPA⁺/Si = 0.007) via a synergistic strategy using potassium bisulfate and seed suspension. The seeds supply abundant structural units to reduce nucleation barrier and accelerate crystallization, while KHSO₄ facilitates silicate polycondensation and suppresses non-MFI impurities. Sulfate ions selectively adsorb on specific crystal facets via hydrogen bonding and induce preferential crystal growth along the c-axis. The c-axis size of Silicalite-1 can be precisely regulated by adjusting dosages of seeds and KHSO₄. Well-defined plate-like crystals were obtained under the conditions of K⁺/Si = 0.25, a seed content of 2.42 wt%, and hydrothermal treatment at 180 °C for 8 h. Scale-up synthesis in a 2 L autoclave verifies its industrial potential. The product exhibits excellent adsorption capacity and cyclic stability toward methylene blue. This work provides a low-cost and green route for morphology-controlled synthesis of MFI-type zeolites. Full article

Rosa damascena Mill. is a medicinal and aromatic species of major pharmacological and economic importance, widely valued for its complex profile of bioactive secondary metabolites. While extensive research has focused on field-grown plants and essential oils, comparatively little attention has been devoted to the behavior of R. damascena under in vitro conditions. Plant tissue culture systems provide controlled platforms for investigating secondary metabolism independently of environmental variability; however, their application to R. damascena has produced heterogeneous and often inconsistent results. This review examines the main in vitro culture systems developed for R. damascena, including callus, suspension, and organ-derived cultures, with emphasis on their capacity to accumulate secondary metabolites. Available evidence indicates that undifferentiated cultures generally fail to reproduce the full metabolic complexity observed in planta, particularly for volatile monoterpenes associated with tissue specialization. Nevertheless, several studies demonstrate that in vitro systems can accumulate phenolic compounds with relevant biological activities, supporting their use as experimental models for investigating metabolic regulation. By integrating early studies with recent advances in plant biotechnology, this review highlights current limitations, unresolved questions, and future perspectives for the use of R. damascena in vitro cultures in medicinal plant research. Full article

To reveal the nonlinear instability mechanism by which the three-degree-of-freedom rotor system of a magnetic-liquid double suspension bearing transforms from stable suspension to periodic vibration, a nonlinear dynamic model considering electromagnetic suspension force, hydrostatic supporting force, rotor unbalance force, and liquid film resistance is established. The equilibrium point of the system is linearized, and the Hopf bifurcation boundary is determined using the Routh–Hurwitz criterion. Numerical simulations are then carried out to investigate the effects of the initial current i₀, supply flow rate q₀, and different initial disturbances on the displacement time histories, phase trajectories, and spatial phase trajectories of the rotor. The results show that, under the given system parameters, the Hopf bifurcation boundary is 0.61 A for the initial current and 9.62 × 10⁻⁵ m³/s for the supply flow rate. Current variation mainly affects electromagnetic stiffness and nonlinear electromagnetic force, whereas flow rate variation primarily changes the hydrostatic load capacity and oil film damping characteristics. Under different initial disturbances, the system may exhibit amplitude attenuation, recovery to stable suspension, or finite amplitude periodic vibration. Experimental results show good agreement with numerical simulations in terms of frequency spectra, displacement time histories, and phase trajectories, thereby verifying the effectiveness of the proposed three-degree-of-freedom dynamic model and Hopf bifurcation analysis method. The results can provide theoretical guidance for parameter matching, stability evaluation, and self-excited vibration suppression of magnetic-liquid double suspension bearings. Full article

This study investigated the production of spodumene concentrate and lithium carbonate from a low-grade pegmatite ore containing approximately 0.26 wt.% Li₂O. The ore consisted predominantly of a quartz–feldspar aluminosilicate matrix with dispersed spodumene mineralization, which complicates conventional processing approaches. Preliminary lithium concentration was performed by dense media separation (DMS) using an industrially applicable ferrosilicon-based suspension. The highest separation efficiency was achieved for the −4.0/+2.8 mm fraction, producing a DMS concentrate containing 5.77 wt.% Li₂O with 98% lithium recovery. The obtained spodumene concentrate was subjected to decrepitation at 1000–1100 °C to convert α-spodumene into the more reactive β-modification, followed by sulfation roasting with concentrated sulfuric acid at 250–270 °C. The productive leach solution obtained after water leaching contained up to 12.1 g/L Li₂O. After purification from iron-bearing impurities and precipitation with sodium carbonate, a lithium carbonate product containing at least 98.8 wt.% Li₂CO₃ was obtained. Approximately 53% of the lithium contained in the original ore was recovered into the DMS feed fraction, whereas the overall lithium recovery into lithium carbonate reached about 45% relative to the ore and approximately 70% relative to the concentrate. Full article

Postbiotics, a type of fermented functional food, are attracting attention alongside the more common pro- and prebiotics. The main production stages—fermentation, thermal inactivation, and drying—significantly influence the functional effects of these foods. This study investigated the impact of pH control during the fermentation of oat flour suspension and optimized spray-drying parameters to produce oat-based postbiotic powders. A Lacticaseibacillus paracasei CBA L74 fermented hydrolyzed oat suspension was analyzed at 37 °C for 24 h, with and without pH control. Both pH conditions produced similar bacterial growth (~10⁹ CFU/mL) and lactic acid (~9 g/L). No significant differences were observed in polyphenols, flavonoids, or antioxidant activity, indicating that pH control did not noticeably improve productivity or the phytochemical properties. The best results—57.40% drying yield and 3.9% relative humidity—were achieved when the postbiotic suspension (diluted 1:4 with water) was mixed 1:1 with maltodextrins, and the spray drying process was conducted with 50 L/min air flow, 200 °C, 3.2 bar atomization pressure, and 5 L/min feed flow. These results support the possibility of scaling the production process from laboratory-optimized parameters and represent a first step toward a cost-effective and industrially feasible route for manufacturing stable oat-based postbiotic powders. Full article

As a core component for restraining cab roll, the lateral stabilizer bar bears continuous complex alternating loads during vehicle operation, making it highly susceptible to fatigue failure that may trigger severe traffic accidents. Therefore, fatigue analysis of the lateral stabilizer bar is of great significance. To address the drawbacks of conventional direct load testing, such as difficult sensor arrangement and long test cycles, this paper proposes a fatigue-load decomposition and life evaluation method, combining multi-body dynamics and virtual iteration. Firstly, target signal spectra of the frame are obtained via real-vehicle road tests, and a high-precision system dynamic model is established with key suspension parameters. Subsequently, virtual iteration technology is adopted to accurately inverse-solve load spectra at critical points of the lateral stabilizer bar. Finally, the finite element model of the lateral stabilizer bar is validated through modal tests, and the fatigue life and vulnerable regions of the lateral stabilizer bar are predicted using the material S-N curve. Compared with traditional physical testing methods, the proposed method effectively avoids barriers to direct testing under complex operating conditions. It not only greatly reduces testing difficulty and time costs but also ensures the accuracy of load extraction and system analysis. Full article

This study experimentally investigates the mixed convection heat transfer performance of CuZnFe₂O₄–water-based magnetic nanofluids in a cylindrical minichannel under the influence of external magnetic fields. Nanofluids with three different volumetric concentrations (0.25%, 0.50%, and 0.75%) were synthesized and characterized in terms of thermophysical properties. The experiments were conducted within the Richardson number range of 0.1–10 to ensure mixed convection conditions, while magnetic field intensities of 220 G, 300 G, and 380 G were applied using custom-built electromagnets. Results show that suspending CuZnFe₂O₄ nanoparticles significantly enhances the heat transfer rate compared to pure water, mainly due to increased thermal conductivity and particle–fluid interactions. The application of a magnetic field further augments the Nusselt number by disturbing the thermal boundary layer and intensifying particle motion, leading to up to 64.4% improvement compared with pure water at similar Reynolds numbers. In addition, Analysis of Variance (ANOVA) and Response Surface Methodology (RSM) were employed to determine the most influential parameters on heat transfer performance and to develop a predictive correlation for the Nusselt number as a function of Reynolds number, nanoparticle concentration, and magnetic field intensity. The findings highlight the combined effects of nanoparticle suspension and magnetic field application as a promising approach for enhancing heat transfer in low-flow mixed convection regimes, offering valuable insights for thermal management in miniaturized cooling systems. Full article

Introduction: Biofilms are communities of microorganisms on wet or moist surfaces that are difficult to remove and can repeatedly release microorganisms. This causes significant problems in many areas, such as food technology and medicine, as biofilms can cause fatal infections in patients. One approach that has not yet been extensively researched is to prevent biofilm formation on surfaces by irradiating them with visible blue or violet light, which is known for its antimicrobial effect on planktonic bacteria. Methods: Various bacterial suspensions (Bacillus subtilis, Pseudomonas stutzeri, Streptococcus cristatus and Pseudomonas syringae) were placed in 24-well MTPs (microtiter plates) and irradiated with violet or blue light for up to 6 days. During this time, they were shaken at room temperature at a frequency of 100 rpm. The irradiation intensities were 0, 10 or 20 mW/cm². After each day, the bacterial suspension was aspirated and the biofilm at the bottom of the well was assessed by absorption measurement and microscopy images. Results: Besides B. subtilis, thin biofilms were found on all well bottoms after 24 h, even on the irradiated microtiter plates. In general, however, the biofilm absorption/scattering was lower on the irradiated MTPs than on the non-irradiated ones. For B. subtilis, irradiation prevented biofilm formation during the observation period. Surprisingly, in most experiments, blue light had a stronger effect than violet light, which does not correspond to the experiences with planktonic bacteria. Conclusion: Violet and blue light exhibits a positive effect on suppressing the formation of new biofilm, but the applied maximum irradiance of 20 mW/cm² was unable to prevent the formation of new biofilm for most of the examined bacteria. Further investigations with higher irradiance levels are necessary to determine whether it is possible to inhibit the formation of new biofilm altogether. Full article

This paper presents the design and experimental validation of a self-contained rotating Halbach array—based demonstrator for electrodynamic suspension (EDS) systems. The proposed platform was developed to bridge the gap between conventional externally powered laboratory testbeds and large-scale EDS vehicles by enabling investigation of levitation behavior under realistic onboard mass and subsystem integration constraints. The system integrates rotating circular Halbach arrays, onboard power supply, sensing, motor control, and structural support within a single levitated architecture. Experimental validation was conducted under a constrained one-degree-of-freedom configuration allowing vertical motion only. The system achieved stable levitation of a 35 kg platform and supported additional payloads approaching a 1:2 ratio relative to the baseline mass, while maintaining air-gap stability within approximately ±0.1 mm. The experimental results further reveal that the operational limit of the system is governed by actuation power and current constraints rather than electromagnetic levitation capability, highlighting a key distinction between self-contained and externally powered EDS systems. The proposed demonstrator provides a compact and practical experimental platform for the validation and performance evaluation of Halbach-array-based EDS systems. In addition, the study presents practical engineering insights regarding payload distribution, actuator saturation, structural integration, and system-level design constraints relevant to future self-contained EDS platforms and control-oriented levitation systems. Full article

Amaranthin is a major red-violet betacyanin of Amaranthaceae and an increasingly relevant natural pigment for food, cosmetic, nutraceutical, and biotechnological applications. This review integrates knowledge from over 100 studies, addressing amaranthin as a chemically defined betalain, distinguishing it from other scientific uses of the term, and evaluates its natural sources, analytical methods, extraction strategies, in vitro production systems, biosynthetic regulation, and biological activity. Cultivated Amaranthus species are among the richest plant sources, with total betacyanins of 46.1–199 mg/100 g fresh weight and amaranthin constituting up to 80.9% of the pigment fraction. Reliable identification and quantification rely on high performance liquid chromatography coupled with a diode array detector (HPLC-DAD), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and ultraviolet–visible (UV–Vis) spectrophotometry, while microwave-, ultrasound-, and green solvent-assisted extraction markedly improve pigment recovery and stability. While plant in vitro cultures, including callus, suspension, and shoot systems, have clarified biosynthetic regulation and offer controlled production platforms, engineered Yarrowia lipolytica CcAmaSy1 currently provides the highest reported yield, reaching 2.97 ± 0.029 g L⁻¹ in fed-batch fermentation. Amaranthin-rich extracts and purified pigments demonstrate antioxidant, anti-inflammatory, antimicrobial, and antiviral potential; however, mechanistic, bioavailability, and in vivo evidence remain limited. Standardized analytical protocols, further investigation of stable high-yield sources, physicochemical stability assessment, and structure–activity studies are identified as priorities for advancing future application-oriented research on this multipotential pigment. Full article