Search Results (3,908)

Welding copper (Cu) and aluminum (Al) is highly demanded for lightweight and cost-effective manufacturing. However, it faces significant challenges. First, substantial differences in physical properties may lead to high residual stresses and distortion. Second, brittle intermetallic compounds (IMCs) readily form at the interface, severely compromising the joint’s mechanical properties and electrical conductivity. Third, the native oxide film on Al impedes effective wetting and bonding. Therefore, effective control over the interfacial microstructure of the welded joint is essential. This review provides a critical analysis and comparison of several typical welding techniques, including laser welding (LW), friction stir welding (FSW), ultrasonic welding (UW), brazing and soldering, and welding–brazing. These analyses focus on their process characteristics, joint microstructures, and corresponding formation mechanisms. Furthermore, this review synthesizes key strategies for enhancing joint quality, including process parameter optimization, introduction of functional interlayers, and external assistance, aimed at optimizing joint microstructure and minimizing defects. Based on the analysis, this work provides comparative insights into process selection and microstructure control, and highlights future directions: advancing novel methods such as magnetic pulse welding and transient liquid phase bonding; developing intelligent real-time process control to suppress brittle IMCs and associated defects; promoting sustainable practices and establishing standardized performance evaluation; and systematically investigating long-term reliability to support the industrial application of robust Cu/Al joints. Full article

The crystallization kinetics of picromerite play a crucial role in optimizing the fertilizer quality. This study developed a crystallization kinetics model of picromerite. Results show that increasing temperature mainly leads to higher supersaturation, which, in turn, enhances both nucleation and growth rates, with significant improvements in crystal size and uniformity. Higher stirring speed was found to have positive effects on crystal nucleation and growth rate. The decrease in supersaturation leads to the diminution of the driving force for crystallization and the gradual decline in crystallization. The study provides a comprehensive analysis of the relationships between these crystallization conditions and the resultant crystal properties. Full article

This study investigated the aroma characteristics of three grades of raw tea leaves and their corresponding jasmine tea products from Guangxi, China. Aromatic profiles of jasmine tea varieties were analysed using two-dimensional gas chromatography-olfactory-mass spectrometry (GC×GC-O-MS), stir bar sorptive extraction (SBSE), and descriptive sensory evaluation. Chemometric methods were applied to compare sensory scores with instrumental data. Volatile compound concentrations and relative odour activity values (r-OAVs) were calculated. The results indicated significant differences in base tea leaf quality: high-grade tea leaf G1 exhibited pure, sweet characteristics, serving as an excellent aroma-absorbing carrier. The scenting process significantly imparted jasmine fragrance to the finished product, although its efficacy was constrained by tea leaf grade. GH1 finished tea exhibited a fresh, vibrant, and rich aroma with a sweet, mellow fragrance and high floral integration. In contrast, GH3, due to its inferior base material quality, yielded a weak aroma after scenting with limited quality improvement. The initial quality of the tea base is the fundamental determinant of the upper limit of the finished jasmine tea’s sensory quality, while the scenting process is the core means of shaping its signature floral aroma. The combination of high-quality tea leaves and precise scenting techniques is essential for developing the fresh, vibrant, and rich flavour profile of premium jasmine tea. This study reveals that the flavour formation of jasmine tea originates from the foundational quality of the tea leaves, providing a theoretical basis for monitoring the aroma quality of jasmine tea produced from different grades of tea leaves. Full article

Cobalt–ruthenium bypiridine–oxalate metal–organic frameworks (MOFs) were synthesized via a solvothermal method with a custom-designed reactor that permits stirring, which can result in changes in the morphology of the structures. In this work, we performed a morphological and structural study of MOFs with varying tris(2,2,bipyridyl) and diclororuthenium(II) hexahydrate ${\left(Ru\right(bpy)}_3^{2+})$ concentrations, demonstrating changes in the size of the MOFs, and these MOFs were used as the luminescent materials in an electrochemiluminescent (ECL) system for glyphosate (Gly) detection, which acts as a coreactant in the light emission of ${Ru\left(bpy\right)}_3^{2+}$. Gly is the most commonly used herbicide worldwide, and our system has a calibration curve range of 10–70 ppm, with a detection limit of 7.6 ppm. Full article

Copper(II) oxide (CuO) nanoparticles are of growing interest due to their versatility in catalysis, energy storage, and environmental remediation. In this work, a novel air-assisted polyol–thermal decomposition method was developed to synthesize crystalline CuO nanoparticles with a controlled size. The reaction used copper(II) acetate in 1,4-butanediol at 140 °C under varying airflow conditions and reaction times, followed by calcination at 400 °C in air. Continuous air bubbling minimized the formation of Cu₂O and metallic Cu, while maximizing the CuO yield with shortened reaction times. The optimal conditions involved a 4 h polyol reaction while purging air at 1800 cm³/min, followed by 4 h of calcination. This method resulted in polycrystalline monoclinic CuO nanoparticles with a size of 73 ± 32 nm, as observed by TEM and XRD. FT-IR and Raman spectroscopy verified the compositional purity of the nanoparticles. To enhance colloidal stability, a citrate coating reaction of CuO was optimized using sodium citrate dihydrate or citric acid in either water or 1,4-butanediol. The optimal coating conditions employed sodium citrate in water with bath sonication and overhead stirring, yielding a zeta potential of −40.6 ± 0.4 mV at pH 7. This work provides a practical and tunable method for producing high-quality CuO nanoparticles suitable for diverse applications. Full article

Background/Objectives: Spherical agglomeration is a particle size enlargement technique with promise to improve micromeritic properties of active pharmaceutical ingredients. In a spherical agglomeration process, an immiscible bridging liquid is added to suspended crystals, inducing agglomeration. Interaction between primary particles and bridging liquid is essential for agglomeration to occur, and mixing is critical as it influences flow profiles and particle suspension. Benchtop-scale stirred tanks are commonly used for spherical agglomeration research. However, there is little consistency in the tank and impeller design, resulting in limited understanding of the influence mixing has on agglomerate properties. Methods: To inform spherical agglomeration reactor design, four industrial standard impeller geometries promoting differing levels of radial and axial flow in the tank were tested in a 1 L stirred tank at impeller speeds ranging from 300 rpm to 600 rpm. The impeller clearance-to-vessel diameter ratio was varied between 0.18 and 0.33 to determine the influence that impeller characteristics have on spherical agglomerates. Corresponding CFD simulations were conducted in ANSYS Fluent to understand vessel flow patterns with different impeller geometries, speeds and clearances. Results: Experimental results suggest impellers with increased power number produce more consistent agglomerates. CFD simulations showed a clear influence of impeller clearance on particle suspension and velocity profile in the tank. Conclusions: Whilst experimental studies and CFD studies have been conducted for spherical agglomeration, this work provides a systematic investigation that compares both CFD and experimental analysis for industrial standard impeller geometries to understand the important, yet underexamined link between impeller characteristics and spherical agglomerate shape and size. Full article

Objectives: The aim of this case report is to highlight the diagnostic challenges of carotid space masses, share clinical experience, and educate clinicians by presenting a case of a rare disease. Introduction: Accessory nerve schwannomas are rare, benign peripheral nerve sheath tumors. They make up only a small percentage of all cervical schwannomas. Given their rarity and varying appearance on imaging, these tumors can be difficult to accurately diagnose. Schwannomas may mimic other carotid space pathologies, such as metastatic lymphadenopathy, paragangliomas, or sympathetic chain tumors. Accurately identifying the nerve of origin before surgery is important for effective surgical planning and neurological function protection. Case Description: A 50-year-old woman presented with an asymptomatic left-sided neck mass. Computed tomography (CT) revealed a cystic lesion with a thick, contrast-enhancing capsule in the left carotid space, causing internal jugular vein compression and partial thrombosis. Subsequent MRI showed a 28 mm × 23 mm × 38 mm well-defined mass with characteristic schwannoma features, including T2/Short tau inversion recovery (STIR) hyperintensity, peripheral enhancement, central cystic degenerative components, and peripheral diffusion restriction with corresponding lower apparent diffusion coefficient (ADC) values. Split-fat sign and fascicular sign were also seen on the MRI. Despite these imaging findings, the radiological interpretation suggested a sympathetic chain schwannoma as the most likely diagnosis. The correct diagnosis of accessory nerve schwannoma was established intraoperatively when the mass was visualized to be attached to the accessory nerve. Conclusions: This case highlights that even with suggestive MRI features, the rarity of accessory nerve schwannomas can lead to misidentification of the nerve of origin. Accurate diagnosis may require intraoperative visualization, thus marking the importance of including accessory nerve involvement in the differential diagnosis of carotid space masses. Full article

The design and optimization of immobilized metal affinity chromatography (IMAC) media are crucial to enhancing the purification efficiency of recombinant proteins. In this study, the agarose-based microspheres are prepared by using a three-factorial Box–Behnken design followed by NTA-Ni²⁺ agarose-based microspheres (ABM) preparation by the “one-step” crosslinking of epichlorohydrin (ECH)–nitrilotriacetic acid (NTA) to efficiently couple the NTA ligand to the surface of the matrix. After preparation, various sophisticated techniques, including SEM, AFM, DSC, FTIR, and SDS-PAGE, were used to analyze the morphological structure, thermal stability, and chemical composition of NTA-Ni²⁺ ABM. The optimal conditions are identified as an emulsifier PP concentration of 8.12 wt%, a stirring speed of 1624.46 rpm, and an oil-phase temperature of 53.86 °C, giving a span value (Y) of 0.50684. SEM, AFM, DSC, and FTIR results showed that the fabricated NTA-Ni²⁺ ABM were structurally stable and had a uniform cross-linking network for up to 8 h of coupling reaction time. The performance results showed that the beads had a high binding capacity for His-tagged proteins (15.2 ± 0.8 mg/mL), and SDS-PAGE results demonstrated the efficient purification ability for target proteins. These findings provide the theoretical basis and a practical solution for the rational design and application of IMAC medium. Full article

Ginseng (Panax ginseng C. A. Mey.), a traditional Chinese medicine, exhibits spleen-fortifying, anti-inflammatory, and anti-ulcerative colitis (UC) effects. Rice-fried ginseng (RFG), prepared by stir-frying with rice together, yields a marked enrichment of rare ginsenosides, which is hypothesized to enhance its anti-inflammatory and anti-UC effects. Therefore, in this study, the chemical compositions of RFG and sun-dried ginseng (SDG) were systematically compared using LC–MS combined with MS-DIAL, and their protective effects against UC were evaluated using lipopolysaccharide (LPS)-induced Caco-2 cells and a dextran sulfate sodium (DSS)-induced UC mouse model. Rice-frying markedly altered the chemical composition of ginseng, and a total of 64 major compounds were identified, of which 31 increased and 33 decreased after processing. These compositional changes were associated with enhanced anti-inflammatory and immunomodulatory effects of RFG. Consistently, RFG enhanced Caco-2 cell viability, decreased TNF-α, IL-1β, and IL-6, and increased ZO-1, occludin, claudin-1, and E-cadherin. In DSS-induced UC mice, RFG attenuated body weight loss, reduced DAI, increased colon length, and decreased the spleen index, accompanied by improved histopathology, reduced pro-inflammatory cytokine levels, and increased expression of tight-junction proteins (TJPs) in a dose-dependent manner. In addition, RFG ameliorated DSS-induced gut microbiota dysbiosis. Metabolomics and network pharmacology analyses highlighted disturbances in linoleic acid and arachidonic acid metabolism and emphasized the involvement of the PI3K–Akt and NF-κB signaling pathways. Western blotting demonstrated decreased phosphorylation of PI3K, Akt, IKKβ, and NF-κB after RFG intervention. Overall, compared with SDG, RFG showed stronger protective effects in vitro and in vivo, accompanied by improved inflammatory readouts, altered lipid-related metabolites and gut microbiota profiles, and reduced phosphorylation of PI3K, Akt, IKKβ, and NF-κB. Full article

1,3-Thiazole derivatives are of interest in pharmacy, medicine, and agriculture as potential biologically active substances. We have proposed for the first time a convenient and effective method for the synthesis of amidoalkylated derivatives of 2-amino-1,3-thiazole. This approach is based on the reaction of amidoalkylated thioureas with α-halocarbonyl compounds. The reaction was carried out under stirring at 20 °C in ethanol with the addition of an equimolar amount of triethylamine to bind the released hydrogen halide. The yield of the obtained 1,3-thiazole derivatives was 68–75%. An attempt to carry out a counter-synthesis by amidoalkylation of the corresponding 2-amino-1,3-thiazole derivative was unsuccessful due to strong resinification of the reaction mass. The structure of the compounds obtained was confirmed by ¹H and ¹³C NMR spectroscopy. The structure was finally confirmed by X-ray structural analysis performed for N-(2,2,2-trichloro-1-((4-phenylthiazol-2-yl)amino)ethyl)acetamide. Full article

In this paper, batch stirred-tank alcoholysis reactions of used and refined sunflower oils were performed with n-octyl, myristyl, cetyl, oleyl, and stearyl alcohols using immobilized lipases Novozym 435 and Lipozyme IM as catalysts. Alcohol conversions ranged from 74% to 94%, with slight differences between used frying sunflower oil and refined sunflower oil. The resulting wax esters were purified via stepwise column chromatography. The different regioselectivity of the biocatalysts led to distinct reaction pathways, and Novozym 435 proved to be the most effective enzyme, providing higher conversions and no detectable by-products. This study demonstrates the valorization of waste frying oils into high-value wax esters through enzymatic alcoholysis, comparing two industrially relevant immobilized lipases and achieving high conversion across multiple long-chain alcohols. The results highlight a sustainable alternative to conventional chemical catalysis and extend biocatalytic applications beyond traditional biodiesel production. By incorporating waste lipids into value-added products, the overall sustainability and circularity of the system are improved, contributing to green and sustainable chemistry. Full article

Caprylic acid (CA) fractionation of serum is a simple and cost-effective method of producing high-quality immunoglobulins. While standardised procedures exist for CA purification of IgG for various animals, no published protocol exists for baboon IgG. This study aimed to optimise an efficient protocol for purifying IgG from baboon serum using CA through a stepwise one-factor-at-a-time (OFAT) approach. The effects of serum pH, CA concentration, stirring time and intensity, dialysis buffer, and lyophilisation were evaluated based on the protein content, with SDS-PAGE profiles and albumin–globulin ratios distinguishing IgG from residual albumin. Serum at pH 5.0 with 7% CA (v/v) produced the highest yield, minimising albumin while maximising IgG content. Lower pH (4.0–4.5) and CA (5–6%) reduced protein content, while a higher pH (5.5–6.0) and CA (8–15%) increased protein, but with elevated albumin and contaminants. Stirring serum vigorously at 1200 rpm for 60 min provided effective precipitation of non-IgG proteins. Lower intensities and shorter times resulted in higher albumin and residual proteins, while excessive stirring caused protein denaturation. Dialysis buffer composition had little impact, while lyophilisation significantly enhanced IgG concentration. The optimal protocol involved serum at pH 5.0, 7% CA (v/v), vigorous stirring (1200 rpm) for 60 min, and dialysis against sodium phosphate buffer (pH 7.4) followed by lyophilisation. The resulting IgG enrichment and purity were comparable to commercial-grade products. This study thus established optimal conditions for the purification of baboon IgG with CA, which could be used to support research in this animal model of immunology. Full article

Hexavalent chromium (Cr(VI)) is a high-priority environmental pollutant due to its strong oxidizing properties, which cause DNA damage and other severe health effects. Conventional detection methods are often costly and lack real-time monitoring capabilities, creating a strong demand for cost-effective, real-time biosensors that meet industrial requirements. In this study, we developed a novel biosensor for continuous Cr(VI) monitoring using a single-chamber microbial fuel cell (MFC). The biological element is an engineered Escherichia coli strain (ChrA-ChrB-E. coli), constructed by introducing Cr(VI)-resistant (ChrA) and Cr(VI)-reducing (ChrB) genes. The presence of Cr(VI) affects bacterial metabolism and electron transfer within the MFC, generating a measurable signal proportional to the contaminant’s concentration. The biosensor demonstrated robust performance and characteristics. The recombinant strain retained functional activity after 450 days of storage at −20 °C. The system exhibited high sensitivity and excellent linearity (R² ≥ 0.999) across a broad Cr(VI) concentration range of 0.015–200 mg/L. During continuous monitoring of chrome tanning and electroplating wastewater, measurements deviated by less than 2.33% from the standard diphenylcarbazide (DPC) method; electroplating deviation was further reduced to −0.69% with EDTA pretreatment. In fishery water, the deviation was higher (−7.12%) due to dissolved oxygen (DO) interference but was reduced to −0.75% after mechanical stirring to remove DO. The biofilm bacterial community remained highly stable over six months in both wastewater types, with the inoculated ChrA-ChrB-E. coli strain maintaining dominance (>99.6%). These results substantiate the feasibility of using this biosensor for continuous, online, real-time detection of Cr(VI) in actual wastewater environments. Full article

The temperature regulation of nonlinear continuous stirred tank reactor (CSTR) processes remains a challenging control problem due to strong nonlinearities, time-delay effects, and sensitivity to disturbances and parameter variations. Conventional proportional–integral–derivative (PID)-based control strategies often fail to provide the robustness and precision required under such conditions, motivating the use of more flexible controller structures and advanced optimization techniques. In this study, an enhanced joint-opposition artificial lemming algorithm (JOS-ALA) is proposed for the optimal tuning of a fractional-order PID (FOPID) controller applied to CSTR temperature control. The proposed JOS-ALA incorporates a joint opposite selection mechanism into the original ALA to improve population diversity, convergence stability, and resistance to local optima stagnation. A nonlinear CSTR model is linearized around a stable operating point, and the resulting model is employed for controller design and optimization. The FOPID controller parameters are tuned by minimizing a composite cost function that simultaneously accounts for tracking accuracy, overshoot suppression, and instantaneous error behavior. The effectiveness of the proposed approach is assessed through extensive simulation studies and benchmarked against state-of-the-art and high-performance metaheuristic optimizers, including ALA, electric eel foraging optimization (EEFO), linear population size reduction success-history based adaptive differential evolution (L-SHADE), and the improved artificial electric field algorithm (iAEFA). The benchmarking set is further extended with the success rate-based adaptive differential evolution variant (L-SRTDE) to broaden the comparative evaluation. Simulation results demonstrate that the JOS-ALA-based FOPID controller consistently achieves superior performance across multiple criteria. Specifically, it attains the lowest mean cost function value of 0.1959, eliminates overshoot, and yields a normalized steady-state error of 4.7290 × 10⁻⁴. In addition, faster transient response and improved robustness under external disturbances and measurement noise are observed when compared with competing methods. Statistical reliability of the observed performance differences is additionally examined using a Wilcoxon signed-rank test conducted over 25 independent runs. The resulting p-values confirm that the improvements achieved by the proposed approach are statistically significant at the 5% level across all pairwise algorithm comparisons. These findings indicate that the proposed JOS-ALA provides an effective and reliable optimization framework for high-precision temperature control in nonlinear CSTR systems and offers strong potential for broader application in complex process control problems. Full article

Cellulose nanofibrils (CNFs), with their high aspect ratio, have been widely used in various resin-based composites. To address the issues of easy agglomeration and poor interfacial compatibility of CNFs in hydrophobic acrylate photosensitive resins, this study adopted γ-methacryloyloxypropyltrimethoxysilane (KH570) for silane modification of CNFs, comparing heating–ultrasonication and heating–stirring methods. Mechanical properties were tested via LCD 3D printer to print splines. FTIR, XRD, and SEM verified successful modification, with the silicon substitution degree of heating–ultrasonication modification reaching 29.35%, significantly higher than heating–stirring (22.76%). Thermal analysis showed the main decomposition temperature increased from 400 °C to 420 °C, while DMA confirmed improved rigidity and glass transition temperature. Mechanical tests revealed a strength–toughness trade-off: the 1 wt% modified CNF composite exhibited a tensile strength of 45.17 MPa (9.41 MPa higher than unmodified CNFs at the same dosage), while a high dosage (3.5 wt%) enhanced toughness but reduced strength. The ultrasound-assisted silanization reaction proposed in this study optimizes the preparation process, achieving dual improvements in modification efficiency and dispersion. In terms of performance regulation, it reveals the quantitative control rules and trade-off characteristics of modified CNF content on the mechanical–thermal properties of the composites, providing a basis for performance customization. This study provides a feasible strategy for CNF modification in photopolymerizable 3D printing composites, expanding nanocellulose’s application in additive manufacturing. Full article