Search Results (19,140)

A new quasi-one-dimensional ejector model for the prediction of ejector performance is carried out, which is based on the theory of ideal gas expansion and free layer development. The model is proposed for calculation of the variable area bypass injector (VABI) and ejector nozzle in the variable cycle engine (VCE), both at the design point and off-design point. The internal structure of ejector nozzle is determined based on an analysis of the flow field of the 2D ejector nozzle Computational Fluid Dynamics (CFD) result. The flow during the expansion section is divided into three parts: primary flow, secondary flow, and mixed layer flow. Combined with the growth rate of mixing layer thickness, the calculation methods of ejector nozzle exit parameters under critical working conditions and blocking working conditions are given, and the calculated results demonstrate a strong consistency with CFD results, maintaining relative errors below 3%. This method is used to evaluate the ejector nozzle capacity quickly in the overall design stage, which provides theoretical support for the design of the main bypass system of a variable cycle engine. Full article

Catalytic upgrading of vacuum residue (VR) is critical for enhancing fuel yield and reducing waste in petroleum refining. This study explores VR cracking over a novel cerium-loaded acidified metakaolinite catalyst (MKA800–20%Ce) prepared via calcination at 800 °C, acid leaching, and wet impregnation with 20 wt.% Ce. The catalyst was characterized using FTIR, BET, XRD, TGA, and GC–MS to assess structural, textural, and thermal properties. Catalytic cracking was carried out in a fixed-bed batch reactor at 350 °C, 400 °C, and 450 °C. The MKA800@Ce20% catalyst showed excellent thermal stability and surface activity, especially at higher temperatures. At 450 °C, the catalyst yielded approximately 11.72 g of total liquid product per 20 g of VR (representing a ~61% yield), with ~3.81 g of coke (~19.1%) and the rest as gaseous products (~19.2%). GC-MS analysis revealed enhanced production of light naphtha (LN), heavy naphtha (HN), and kerosene in the 400–450 °C range, with a clear temperature-dependent shift in product distribution. Structural analysis confirmed that cerium incorporation enhanced surface acidity, redox activity, and thermal stability, promoting deeper cracking and better product selectivity. Kinetics were investigated using an eight-lump first-order model comprising 28 reactions, with kinetic parameters optimized through a genetic algorithm implemented in MATLAB. The model demonstrated strong predictive accuracy taking into account the mean relative error (MRE = 9.64%) and the mean absolute error (MAE = 0.015) [MAE: It is the absolute difference between experimental and predicted values; MAE is dimensionless (reported simply as a number, not %. MRE is relative to the experimental value; it is usually expressed as a percentage (%)] across multiple operating conditions. The above findings highlight the potential of Ce-modified kaolinite-based catalysts for efficient atmospheric pressure VR upgrading and provide validated kinetic parameters for process optimization. Full article

To further investigate the collision process and tectonic regime transition between the North China (NCB) and South China Block (SCB), two magnetotelluric profiles were arranged across the Dabie Orogeny Belt (DOB) and eastern SCB. We then obtain the lithospheric resistivity models. The prominent feature revealed by our new model is an extensive conductive arc from the lower crust to the upper mantle, across the Jiangnan orogenic belt (JNOB) and the eastern Cathaysia Block (CAB). In addition, a huge resistor beneath the conductive arc is revealed, which is separated by a conductive wedge. Combining the heat flow and seismic tomographic imaging results, the conductors are to contain a large amount of hot material that present as the detachment layers (belts) controlled by the two subduction slabs. Considering multi-phase magmatism in the study area, new models suggest an intracontinental tectonic event in eastern CAB. Therefore, we propose a reliable tectonic process that occurred in the study area, including five stages: (1) an eastward intracontinental subduction and orogen carried out in CAB before the collision between SCB and NCB; (2) an extensional structural developed in CAB, following the subduction slab wrecking/sinking; (3) after the collision with NCB, the SCB crust/lithosphere thickened following the westward subduction of the Paleo-Pacific plate; (4) following the westward Yangtze slab sinking, the regional extension developed with the asthenosphere upwelling beneath SCB; (5) afterwards, the SCB was welded into one continent in a setting of westward compression. Full article

Microfluidic chips made of polydimethylsiloxane (PDMS) have shown significant application potential in aquatic environments with high microbial density, such as “marine ranches”, due to their high-throughput, high-efficiency and high-precision detection capabilities. This technology can rapidly identify pathogenic microorganisms or harmful particles in aquaculture systems, thereby providing urgently needed innovative methods for implementing preventive measures and enhancing aquaculture productivity. By regulating the micro-nano scale channel structure, microfluidic technology can precisely control fluid flow patterns, offering new insights and effective solutions for microbiological research and the separation and analysis of particulate matter. This paper first provides a concise overview of the application of microfluidic chip technology in the analysis of marine microorganisms. Subsequently, it focuses on the “compliance” phenomenon in PDMS-based microfluidic systems, systematically reviewing the potential mechanisms, latest progress and impacts of compliance behavior in mechanically elastic materials such as PDMS. Additionally, this article also investigates the role of “compliance” in key processes of microfluidic technology application, including the capture, separation, enrichment and detection of microorganisms and particles. Moreover, the relationship between surface wettability engineering and compliance phenomena is also explored. We believe that this review will contribute to enhancing the understanding and control of the mechanical behavior of microfluids and the particles they carry within microfluidic systems, providing valuable theoretical insights and practical guidance for researchers in this field. Full article

Dopamine D2-like receptors, including D2, D3, and D4, are members of the aminergic G protein-coupled receptor (GPCR) family and are targets for neurological disorders. The development of subtype selective ligands is important for enhanced therapeutics and reduced side effects; however, it is challenging to design and develop selective ligands owing to the high degree of sequence homology among D2-like subtypes. To gain insight into the structural basis of subtype selectivity of piperazinylalkyl pyrazole/isoxazole analogs for D2-like dopamine receptors, we carried out 3D quantitative structure–activity relationship (3D-QSAR) and molecular docking studies. The 3D-QSAR models for the D2, D3, and D4 subtypes showed robust correlation coefficients (r²) of 0.960, 0.912, and 0.946, as well as reliable predictive values (Q²) of 0.511, 0.808, and 0.560, respectively. Contour map analysis revealed key structural determinants for ligand activity, highlighting the distinct steric and electrostatic requirements for each subtype. These findings were further rationalized by molecular docking studies, which confirmed that interactions with non-conserved residues modulate binding affinity. Crucially, our analysis identified a critical structural basis for D4 subtype selectivity. This selectivity is attributed to a spatial constraint within the hydrophobic pocket formed by TMs 3, 5, and 6. This constraint restricts the orientation of bulky substituents on the 4-phenylpiperazine moiety. These findings provide actionable structural insights for the rational design of next-generation subtype-selective antagonists for D2-like dopamine receptors. Full article

Tribological tests were conducted on eutectic white cast iron subjected to directional solidification (resulting in a directionally oriented microstructure) and, for comparison, on white cast iron with an equiaxed (non-directional) structure. The tests were performed under dry sliding conditions on a pin-on-block rig using Cu, AlSi12CuNiMg alloy, AlSi12CuNiMg + SiC composite, and steel grade 1.3505. The friction coefficient and wear rates of these materials were systematically compared. Quantitative and qualitative evaluations of the wear tracks formed on the test specimens were carried out using profilometry. The results demonstrate that the directionally solidified white cast iron exhibits improved friction coefficient stability and reduced wear in the specific tribological pairs. The oriented directional structure demonstrated more favourable interactions when paired with AlSi12CuNiMg + SiC composite and 1.3505 steel. These tribological combinations exhibited reduced roughness values across selected cross-sectional analyses, resulting in correspondingly lower Sa parameter measurements. This finding suggests a promising new application for inserts made of directionally structured white cast iron in structural components requiring enhanced wear resistance at elevated temperatures. Full article

The concept of a genome signature broadly refers to characteristic patterns in DNA sequences that enable the identification and comparison of species or individuals, often without requiring sequence alignment. Such signatures have applications ranging from forensic identification of individuals to cancer genomics. In comparative genomics and evolutionary biology, genome signatures typically rely on statistical properties of DNA that are species-specific and carry phylogenetic information reflecting evolutionary relationships. We propose a novel genome signature based on the compositional structure of DNA, defined by the distributions of strong/weak, purine/pyrimidine, and keto/amino ratios across DNA segments identified through entropic segmentation. We observe that these ratio distributions are similar among closely related species but differ markedly between distant ones. To quantify these differences, we employ the Jensen–Shannon distance—a symmetric and robust measure of distributional dissimilarity—to define a genome-to-genome distance metric, termed Segment Compositional Distance ($\mathcal{D}$). Our results demonstrate a clear correlation between $\mathcal{D}$ and species divergence times, and also that this metric captures a strong phylogenetic signal. Our method employs a genome-wide approach rather than tracking specific mutations; thus, $\mathcal{D}$ offers a coarse-grained perspective on genome compositional evolution, contributing to the ongoing discussion surrounding the molecular clock hypothesis. Full article

Shotcrete used in underground structures like tunnels is susceptible to sulfate and chloride erosion. In order to systematically study the deterioration law and mechanism of the durability of high-performance shotcrete under a salt erosion environment, the durability test of high-performance shotcrete was carried out by an indoor long-term immersion test using a clear water solution, Na₂SO₄ solution, and Na₂SO₄ and NaCl mixed solution as erosion mediums. A comparative study was conducted on the effects of different curing time, erosion time, erosion medium, and erosion direction on the physical and mechanical properties and SO₄²⁻ content. The microstructure was analyzed to reveal the time evolution process and mechanism of the durability of high-performance shotcrete under coupled erosion. The results show the following: (1) The mass change rate of high-performance shotcrete under the action of coupling erosion increases first, then decreases, and then increases. The compressive strength of the surface perpendicular to the jet direction is better than that of the surface along the vertical jet direction. (2) The diffusion depth of SO₄²⁻ along the injection direction is larger, and the content of SO₄²⁻ is larger at the same depth. The existence of Cl⁻ delays the diffusion of SO₄²⁻ to a certain extent. (3) In the early stage of erosion, the corrosion expansion products generated by the external SO₄²⁻ entering the concrete will fill the original pores and cracks, which improves the durability of the concrete. In the late stages of erosion, the accumulation of corrosion products increases, which accelerates the deterioration of its durability. Full article

The waviness defect, a common manufacturing flaw in composite structures, can significantly impact the mechanical performance. This study investigates the effects of wrinkles on the ultimate load and failure modes of two Carbon Fiber Reinforced Composite (CFRC) laminates through compressive experiments and simulation analyses. The laminates have stacking sequences of [0]_10S and [45/0/−45/90/45/0/−45/0/45/0]_S. Each laminate includes four different waviness ratios (the ratio of wrinkle amplitude to laminate thickness) of 0%, 10%, 20% and 30%. In the simulation, a novel multiaxial progressive damage model is implemented via the user material (UMAT) subroutine to predict the compressive failure behavior of wrinkled composite laminates. This multiscale analysis framework innovatively features a 7 × 7 generalized method of cells coupled with stress-based multiaxial Hashin failure criteria to accurately analyze the impact of wrinkle defects on structural performance and efficiently transfer macro-microscopic damage variables. When any microscopic subcell within the representative unit cell (RUC) satisfies a failure criterion, its stiffness matrix is reduced to a nominal value, and the corresponding failure modes are tracked through state variables. When more than 50% fiber subcells fail in the fiber direction or more than 50% matrix subcells fail in the transverse or thickness direction, it indicates that the RUC has experienced the corresponding failure modes, which are the tensile or compressive failure of fibers, matrix, or delamination in the three axial directions. This multiscale model accurately predicted the load–displacement curves and failure modes of wrinkled composites under compressive load, showing good agreement with experimental results. The analysis results indicate that wrinkle defects can reduce the ultimate load-carrying capacity and promote local buckling deformation at the wrinkled region, leading to changes in damage distribution and failure modes. Full article

Despite significant advances in understanding the genetics of Parkinson’s disease (PD) and Parkinsonism, the diagnostic yield remains low. Pathogenic variants of GBA1, which encodes the lysosomal enzyme β-glucocerebrosidase and causes recessive Gaucher dis-ease, are recognized as the most important genetic risk factor for PD in heterozygous carriers. This study focuses on the functional genomics of rare genetic variations in other lysosomal hydrolytic enzymes genes in patient-derived fibroblasts. We examined 49 early-onset PD patients using whole exome sequencing and in silico panel analysis based on a curated PD gene list. Two patients were found to carry the p.Asp313Tyr variant in the X-linked GLA gene (encoding GALA, typically associated with Fabry disease), and one patient carried the p.Arg419Gln variant in GLB1 (encoding β-Gal, linked to the recessive GM1 gangliosidosis and mucopolysaccharidosis type IVB). The in silico study of both variants supports a potentially damaging impact on the encoded protein function and structural destabilization. Additional candidate variants were found related to lysosomes, Golgi apparatus and neurodegeneration, suggesting a multifactorial contribution to the disease. However, none of these variants met diagnostic standards. Functional assays showed a significant decrease in GALA expression and partial retention of the enzyme in the trans-Golgi network in fibroblasts with GLA:p.Asp313Tyr, while altered Golgi morphology was observed in fibroblasts with GLB1:p.Arg419Gln. Moreover, all patients exhibited abnormalities in lysosomal morphology, altered lysosomal pH, and impaired autophagic flux. Our findings suggest that rare, heterozygous variants in lysosomal-related genes, even when individually insufficient for monogenic disease, can converge to impair lysosomal homeostasis and autophagic flux in EOPD. The underlying genetic and cellular heterogeneity among patients emphasizes the importance of combining genetic and functional approaches to better understand the mechanisms behind the EOPD, which could enhance both diagnosis and future treatments. Full article

The AA2124 aluminium alloy-based metal matrix composites (MMCs) reinforced with the silicon carbide (SiC) were examined under tensile creep at 300 °C. The tests were carried out for the materials of different SiC particle size (3 µm and 0.6 µm) and amount (17 vol.% and 25 vol.%). Creep curves under different constant stresses are presented. A high stress sensitivity of the composites tested was identified for a very narrow range of stress values. As a result, a threshold stress range separating the slow and fast creep stages was easily identified at around 5 Mpa for the composite with a larger SiC particle size and lower content and around 1 Mpa for the two other composites. It means that a very small change in stress applied to the structural element at elevated temperatures may lead to its very rapid collapse or even the destruction of the whole structure. The experimental programme was supplemented by the microstructural observations carried out using the scanning electron microscopy providing data necessary for better understanding the damage mechanisms of the material subjected to creep. An influence of voids on the mechanical response and fracture zones was identified. Attention was paid to the nature of degradation of the composites. Full article

The CYP2D6 gene is a highly polymorphic pharmacogene involved in the metabolism of 25% of commonly used drugs. We aim to assess the feasibility of extracting relevant pharmacogenomic information from Whole Genome Sequencing (WGS) data and to highlight any difference in CYP2D6 allele frequencies between the northeastern Italian and European populations. To achieve this aim, WGS was performed on two cohorts: 664 individuals from six different isolated communities (FIC) and 123 outbred Italian individuals (FOP). In silico CYP2D6 genotyping was performed and allele frequencies from the FIC cohort were compared to those of FOP and European individuals from 1000 Genomes. Interestingly, 18 alleles identified in FIC were absent in the control cohorts. In particular, 13 individuals carried the extremely rare CYP2D6*28x2 allele, whose activity is unknown. Moreover, we identified a carrier of the CYP2D6*34x2 allele, which has never been described before. The population structure and genetic differentiation of the cohorts were investigated, revealing that the genetic isolates differ only slightly from the outbred and the European populations, but still offer new insight into CYP2D6 heterogeneity. The findings described here will be relevant to tailoring the treatments in the northeastern Italian population. Full article

The work progress control is a key aspect for correcting deviations in construction, but currently is a task still carried out very manually by personnel moved to the execution place. This work proposes to digitize and automate the procedure through the combination and contrast of digital models of the actual state of the work and the theoretical planning. The models of the real situation are generated from the laser scanning executed by drones, the theoretical planning is reflected in the BIM4D models of the project, and their combination is automated with Feature Manipulation Engine (FME) visual programming routines. A web-based digital twin platform allows access to the end user of the service in an agile way. The methodology developed has been validated with its application on a residential building in the structural erection phase in Helsinki (Finland). Full article

In deep-sea oil and gas development scenarios, deep-sea dual-channel connectors often face the risk of seal failure due to internal and external temperature difference loads. To address this issue, this paper systematically establishes equivalent heat transfer models for the key parts of the connector based on the third-type boundary condition. On this basis, the quantitative correlation between the equivalent thermal conductivity, composite heat transfer coefficient and temperature of each part is explored. Using the finite element numerical simulation method, the transient temperature field of the connector under three working conditions (heating, cooling and temperature shock) is simulated and analyzed, revealing the temperature distribution characteristics and temperature change trends of the maximum temperature difference of each key component of the connector; combined with thermal–structural coupling simulation, the temperature field is converted into static load, to determine the behavior of the contact stress on the sealing surface under different temperature–pressure coupling working conditions; in addition, by placing the test prototype in a high-low temperature cycle chamber, the seal performance tests under pressurized and non-pressurized working conditions are carried out to verify the reliable sealing performance of the connector under variable temperature conditions. The results of this paper provide comprehensive theoretical support and an experimental basis for the thermodynamic optimization design of deep-sea connectors and the improvement of the reliability of the sealing system. Full article

Alloys from the Ag-Ti system are extremely promising and offer the possibility of versatile applications owing to their attractive properties. However, due to the experimental difficulties caused, among others, by the significant difference in melting points of the components, most of the information on the thermodynamic properties available in the literature has been obtained by computer methods. Therefore, the main aim of this work is to extend the current knowledge about the experimentally determined thermodynamic properties of selected alloys from the Ag-Ti system. Within the scope of this work, calorimetric studies were carried out using Differential Scanning Calorimetry (DSC) and high-temperature drop calorimetry measurements. The first of the aforementioned methods was used to determine the characteristic temperature of the Ag_0.43Ti_0.57 alloy synthesized by mechanical alloying. Using titanium hydride instead of titanium for the preparation of alloys from the Ag-Ti system has not yet been reported in the literature. This paper presents a complete structural characterization (SEM, XRD studies) of the above alloy produced by this method. The second technique was applied to ascertain the mixing enthalpy change in the alloys in the composition range between x_Ti = 0.02–0.226, and for the measurements of the formation enthalpy of the AgTi intermetallic phase. Based on the calorimetric results obtained in this study, along with the relevant thermodynamic data from the literature, the Ag-Ti phase diagram was reoptimized. Full article