Search Results (6,594)

To meet the demands for high-density integration and broadband RF performance in next-generation electronic equipment, this paper investigates the structural design and process sensitivity of vertical interconnects in three-dimensional stacked system-in-package (3D-SiP). Based on quasi-coaxial matching and low-impedance compensation techniques, three typical vertical interconnect structures are designed: the PCB-BGA-SiP microstrip structure achieves S₁₁ better than −15 dB and S₂₁ < 0.3 dB within 2–20 GHz; the lower stripline–BGA–upper microstrip structure achieves S₁₁ better than −27 dB; the lower microstrip–BGA–upper microstrip structure achieves S₁₁ better than −18 dB within 1–23 GHz. Isolation simulation shows that the isolation between adjacent channels exceeds 55 dB within 25 GHz. For process sensitivity evaluation, physical samples of gold wire bonding parameters (length, diameter, number) were fabricated and tested for S₁₁, confirming that the dual-wire topology extends the effective bandwidth to 2–20 GHz (a 54% improvement over single wire), the third-wire marginal gain is only ~5%, and 25 μm diameter offers the best overall performance. For BGA ball radius and pad pitch, parametric sensitivity analysis via Ansys HFSS was performed (not experimentally validated process variation results), identifying the optimal BGA radius as 0.245 mm with an allowable variation of ±0.015 mm, and the pad center-to-center distance should be controlled near 0.8 mm. Based on these findings, process control strategies are proposed: low-loop wire bonding (loop height < 50–80 μm) with statistical process control; substrate warpage controlled through symmetric copper filling, a thick-middle dielectric stack-up, and distributed symmetric cavity layout, combined with eutectic pressure of 1.5 kPa, validated on 10 fabricated substrates with peak warpage consistently < 80 μm, void rate 4.75%, and solder overflow 94%; and BGA soldering using high-precision vision alignment and controlled collapse (20–35%). This work provides a theoretical basis and practical process pathway for transitioning 3D-SiP vertical interconnects from ideal design to mass production. Full article

The effects of wide-ranging service temperatures on interfacial bond transfer and slip evolution in high-strength concrete-filled steel tube members have not yet been systematically characterized. A test program involving 15 circular specimens was carried out at temperatures between −60 °C and 60 °C with steel tube wall thicknesses of 2 mm, 3 mm, and 4 mm. Particular attention was given to interface failure patterns, slip development, and stress transfer during loading. Cooling markedly enhanced the interfacial resistance, whereas heating produced a moderate reduction. The increase observed at subzero temperatures was smaller than that commonly reported for conventional concrete-filled steel tubes. Bond capacity also declined as the diameter-to-thickness ratio increased because of reduced confinement from the steel tube. Regression of the experimental data produced expressions for ultimate bond strength and the associated slip. A piecewise constitutive relation was then formulated to represent the complete bond–slip process. The proposed relation was implemented in ABAQUS through distributed nonlinear connector elements and temperature-dependent material properties. Numerical predictions showed close agreement with the measured load–slip responses, characteristic loads, and stress distributions. These results provide a modeling basis for HSCFST members exposed to severe cold and large temperature fluctuations. Full article

Biodeterioration of mineral coating–substrate systems develops through interactions among microbial colonization, environmental exposure and the physicochemical properties of the coating, interface and substrate. Microbial presence, however, is still often taken as evidence of deterioration even when a causal link with material transformation or loss of performance has not been demonstrated. This critical review examines mechanisms and diagnostic indicators relevant to cement-, lime-, gypsum-, silicate- and polymer-modified mineral coatings. It distinguishes between susceptibility, microbial colonization, biological activity, chemical and mineralogical transformation, microstructural and moisture-transport alteration, and mechanical or functional deterioration. Reported mechanisms include acidification, mineral dissolution, ion redistribution, secondary mineral precipitation, pore opening or filling, moisture redistribution, cracking, cohesion loss and interfacial deterioration. These responses can be non-monotonic and depend strongly on material composition and exposure conditions. Most material-response indicators have limited biological specificity, since similar changes may result from carbonation, salts, moisture, pollutants or aging. Reliable attribution depends on convergence between microbial activity and spatially corresponding material transformation, with plausible abiotic mechanisms considered at the same time. Five evidentiary categories are distinguished: susceptibility, microbial colonization, active microbial process, probable biodeterioration and confirmed biodeterioration. On the basis of current evidence, universal numerical severity thresholds are not justified. Full article

Modulated by diverse climatic and oceanic forcing factors, the sea ice durations in the nearshore waters of the Bohai and northern Yellow Seas exhibit complex fluctuations on interannual and interdecadal timescales. Systematically analyzing the oscillatory patterns and trend stationarity of long-term sea ice duration series provides robust theoretical and practical guidance for coastal ice disaster early warning, marine industrial safety, and coastal economic sustainability. This study analyzes annual sea ice duration series recorded over 59 winters (1966–2024) at six representative coastal marine stations spanning the full spatial gradient of regional ice regimes across the Bohai and northern Yellow Seas. Isolated missing values were filled by linear interpolation, and the Ljung–Box Q test confirmed that the residual series do not follow a white-noise process. Two categories of stationarity tests—conventional unit root tests and Fourier series expansion-augmented stationarity tests—are adopted to quantify the stationary properties, nonlinear trend transitions, and smooth structural breaks of sea ice durations at each station. The results reveal marked spatial differences in interannual volatility and evolutionary trends among stations: two smooth transitional shifts are identified for Bayuquan (BYQ) and Qinhuangdao (QHD), whereas the remaining stations each exhibit a single shift. Long-term trends range from multistage declining patterns to a rising pattern for Donggang (DGG), while Zhimaowan (ZMW) shows a statistically insignificant trend. This work provides quantitative statistical evidence for sea ice risk evaluation and coastal structural safety protection across the Bohai and northern Yellow Seas, and offers actionable decision-making references for climate change adaptation and integrated coastal zone governance in ice-affected coastal zones worldwide. Full article

Automated inspection of prepared meals is important for improving food safety, quality assurance, and production efficiency. However, vision-based inspection remains challenging because boxed meals contain multiple adjacent food items with irregular shapes, varying portion sizes, and visually similar appearances, while oily surfaces may introduce specular reflections that degrade image quality. This study presents a vision-based framework for multi-object recognition and quantitative defect analysis in complex meal images, with Chinese-style lunch boxes used as representative test samples. The framework integrates region-of-interest (ROI) extraction, fixed-grid regional feature representation, deep neural network (DNN) classification, flood-filling post-processing, and empirical food-quantity thresholds. The lunch-box ROI is first extracted using the Hough transform, followed by median filtering to suppress reflection noise. The ROI is partitioned into 6 × 6 regions, from which the mean and standard deviation of RGB, HSV, and CIE Lab* color components are extracted and classified using a DNN. Flood filling is subsequently applied to refine the classification results, and category-specific empirical thresholds are used to identify missing food items and insufficient portions. Foreign objects are detected as an additional abnormal category. Under the evaluated experimental conditions, the proposed framework achieved an overall image classification rate (CR) of 96.45%, a defective-image detection rate (1−β) of 97.76%, a normal-image false alarm rate (α) of 5.34%, and a defective-image misclassification rate (γ) of 0.82%. Sensitivity experiments involving illumination variation, two lunch-box configurations with different food compositions, and conveyor-based image acquisition further demonstrated the feasibility and stability of the framework under the evaluated laboratory and prototype conditions. These findings support the feasibility of the proposed lightweight framework for vision-based quality inspection of representative boxed meals, while broader validation across meal types, contaminants, and industrial production environments remains necessary. Full article

The aim of this study was to investigate the effect of 3D printing parameters on the surface topography and surface wettability properties of PET-G samples intended for potential tribological applications. Surfaces produced with varying fill rates and two layer heights were examined using focus variation microscopy and water contact angle measurements. The statistical analysis showed that the infill percentage has a significant influence on wettability, but did not reveal a significant influence of layer height on the observed contact angles. The results showed that surface characteristics are strongly dependent on process conditions, and the relationships between roughness parameters and wettability are mostly nonlinear. The parameters Są and Sq tended to decrease the contact angle as roughness increased, whereas Sp, Sv, and Sz showed no clear relationship with contact angle values. In contrast, Ssk and Sku showed a positive, linear correlation with the contact angle, indicating an important role of the statistical shape of the surface height distribution. The results confirm that the functional properties of additively manufactured surfaces depend not only on the amplitude of surface irregularities but also on their spatial organization and asymmetry. Full article

To address the challenges associated with severe lost-circulation formations, including large loss-channel dimensions, rapid fluid losses, and the tendency of conventional bridging or physical-filling materials to accumulate at fracture entrances rather than penetrate deeply into fractures and form stable pressure-bearing plugs, a slag–fly ash–gypsum–sodium ethylenediamine tetramethylene phosphonate (EDTMPS) controlled-setting lost-circulation system was developed in this study. A 4 wt% bentonite base slurry was used as the dispersion medium, while a slag–fly ash blend served as the principal cementitious component. Gypsum was used to regulate the setting reaction, and EDTMPS was employed to control the slurry-thickening process, thereby coordinating slurry pumping, fracture filling, and in situ setting. The operational feasibility, consolidation capability, and short-term pressure-bearing performance of the system were evaluated through formulation screening, tests of slurry placement and hardened-material properties, water-based drilling-fluid contamination evaluation, and pressure-bearing tests in regular fractures with apertures of 1–5 mm. The results showed that, at a slag-to-fly-ash mass ratio of 6:4, the hardened material exhibited a compressive strength of 12.91 MPa. Within the investigated dosage range, the highest observed 1 d and 3 d compressive strengths were both obtained at a gypsum dosage of 2.0%. Under conditions of 150 °C and 50 MPa, the addition of 1.5 g of EDTMPS extended the slurry thickening time from 2.6 h to 7.3 h, while the compressive strength of the hardened material after 24 h of curing reached 17.18 MPa. At a water-based drilling-fluid contamination ratio of 30%, the compressive strength of the hardened material was 13.86 MPa, corresponding to a strength-retention ratio of 80.7%. In straight, constant-aperture fractures with apertures of 1.0, 2.0, 3.0, 4.0, and 5.0 mm, the maximum pressures sustained by the plugs before breakthrough were 16, 15, 14, 13, and 12 MPa, respectively, and decreased with increasing fracture aperture. These results indicate that, within the formulation range, water-based drilling-fluid contamination conditions, and short-term pressure-bearing conditions in regular fractures investigated in this study, the system can coordinate slurry-thickening control, 24 h hardened strength, contamination tolerance, and pressure-bearing performance in regular fractures. The findings provide a verifiable formulation-design approach for reconciling the placement-time window of lost-circulation materials for severe lost circulation with their post-placement pressure-bearing capacity. Full article

Skeleton-based human action recognition can support digital construction and renovation monitoring by converting worker motions into structured information for safety and process management. However, workers are often occluded by tools, materials, furniture, and temporary structures, resulting in incomplete skeleton sequences and reduced recognition accuracy. In this study, we propose a recognition-guided generative skeleton imputation approach for robust action recognition under severe occlusion. Our method first evaluates an incomplete skeleton and applies imputation only to samples with uncertain recognition results. For these samples, a pretrained OmniControl model generates multiple plausible motion candidates from the observed skeleton information and action descriptions. The candidate most consistent with the observed motion is selected and used only to fill missing regions while preserving reliable joints, and the completed skeleton is then re-evaluated by the same recognition model. Experiments on 565 collected indoor renovation clips and the NW-UCLA dataset, using four recognition models and nine occlusion conditions, demonstrated overall improvements in recognition robustness, with average accuracy increasing from 61.01% to 65.00% on the collected dataset and from 42.63% to 50.31% on NW-UCLA. These results demonstrate the potential of selective generative imputation for improving action recognition under incomplete skeletal observations. Full article

In view of the differences in the specified substitution rates of construction and demolition waste (C&DW) recycled materials in road applications between China and other countries, this study focuses on a highway reconstruction and expansion project in Guangdong Province, China, and systematically analyzes the influence of the recycled aggregate substitution rate on the road performance of subgrade filler and cement-stabilized recycled aggregate (CSRA). Based on the current domestic JTG series specifications, combined with a literature review and comparative analysis, the effects of particle size, maximum dry density (MDD), optimum moisture content (OMC), and California bearing ratio (CBR) on the compactness, stability, and strength of subgrade fillers under different substitution rates were systematically evaluated. Furthermore, the study investigates the variation in the performance of CSRA, including crushing value, 7-day unconfined compressive strength, 90-day splitting tensile strength, compressive rebound modulus, and scouring resistance. The results indicate that (1) when recycled materials are used for roadbed filling, they can meet the specified compactness and CBR value requirements at a 100% substitution rate. The key is to control the impurity content and maximum particle size during the crushing process. (2) When recycled materials are used in a pavement structure layer, their performance is significantly affected by the material source and substitution rate. CSRA produced from demolished old pavements and bridges exhibits better performance. It is recommended that the substitution rate should not exceed 80% for subbase layers and 50% for base layers. This research provides recommended substitution rates and material-selection guidelines for the scientific utilization of C&DW recycled materials for specific engineering applications. The study has practical significance for improving C&DW resource utilization, reducing engineering costs, and lowering carbon emissions. Full article

Nickel (Ni) and copper (Cu) are essential soil micronutrients that are beneficial for plant growth and development when applied at the right levels to deficient soils. However, they can also be of concern if excessive application leads to accumulation in soil, causing soil fertility problems that can compromise food production as well as result in human exposure to these metals if they enter the food chain. The application of Ni and Cu salts can strongly influence the nitrogen (N) cycle as they can stimulate soil microbiological activity that leads to N losses to the atmosphere. A laboratory incubation was conducted to study the effect of these metal salts on gaseous N emissions. Copper sulphate (CuSO₄) and nickel sulphate (NiSO₄) were applied at rates below soil toxicity (3.0 kg Ni/ha and 7.5 kg Cu/ha), together with ¹⁵N-labelled-urea (rate 100 kg N/ha) and under two soil water-filled pore space (WFPS) conditions: continuous anaerobic (75% WFPS) versus aerobic (50% WFPS) followed by an anaerobic (75% WFPS) cycle. Results showed no significant effect of the Ni application on nitric oxide (NO) emissions at the low rates applied. However, there was an indication of a meaningful (p = 0.051) production of this gas under aerobic soil conditions. No N₂ emissions were observed from any treatment (only expected to occur under anaerobic conditions) during the 43 days of the incubation, which could suggest that, as for Ni, the selected Cu application rate may not clearly stimulate the complete denitrification process to produce N₂. It is possible that the expected increase in N₂ emissions or larger NO emissions were counteracted by the low amount of soil-extractable Cu and Ni available after application because of binding processes with the clay fraction (48% clay) and the acid nature of the Cambisol used in the incubation. Further research into the effect of metal applications to contrasting soil types, with varied application rates and repeated application events, and under differing soil moisture conditions on N emissions is required. Furthermore, experiments should also be conducted at finer scales to elucidate the specific effect of these metal application rates on the biochemical processes responsible for the N gases produced. Full article

Resin Transfer Molding (RTM) is a broadly applied composite fabrication technique in which liquid resin is injected into a sealed mold housing a fibrous preform. This technique enables the industrial-scale production of large, complex-shaped components while ensuring high quality and excellent material properties. A notable phenomenon in the Resin Transfer Molding process, particularly when vegetable fibers are used as reinforcement, involves resin absorption by the fibers during the filling process, which causes a deceleration of the fluid flow front, leading to an increase in mold filling time. This phenomenon has been scarcely investigated in the scientific literature, particularly under non-isothermal situations. In this context, this paper focuses on the resin injection in a closed and heated mold, emphasizing the evaluation of the capillary number of the fluid flow. The model incorporates a transient, radial, and 3D flow, variable resin viscosity, and includes the effect of resin absorption by the fibers. Simulations were carried out using CFD techniques, evaluating the effect of fixed injection gauge pressure (2.0 bar) or volumetric flow rate (3.5 × 10⁻⁸ m³/s) on the infiltration transient behavior. The numerical results of the capillary number of the flow, resin viscosity, and resin superficial velocity as a function of radial position were analyzed. Based on the analysis of the capillary number field, with the sole objective of minimizing the potential formation of voids in the manufactured composite, optimal operating parameters were identified, namely, a mold heating temperature of 30 °C and an optimal resin injection condition consisting of a constant volumetric flow rate of 3.5 × 10⁻⁸ m³/s. Further, the volumetric fraction, pressure, and temperature fields are presented and examined. The numerical modeling used builds upon a previously validated numerical framework and extends its application by evaluating the potential generation of voids through the analysis of the capillary number field. Full article

This study developed alkali-activated binders based on biomass power plant ash (BPPA) and ground granulated blast furnace slag (GGBFS) for potential application in coal-mine goaf backfilling. Five precursor proportions, ranging from 100% BPPA to 100% GGBFS, were investigated to clarify the influence of precursor composition on fresh properties, mechanical performance, reaction-product evolution and microstructural development. Increasing the GGBFS content reduced slump and shortened both initial and final setting times, indicating accelerated precursor dissolution and early structural build-up. Compressive strength increased nonlinearly with GGBFS incorporation. Multiscale characterization consistently demonstrated that GGBFS promoted the transformation of the initially quartz-rich and weakly reactive BPPA system into a calcium-rich aluminosilicate binding matrix. This transformation was accompanied by changes in the Si-O-T bonding environment, increased formation of hydrated reaction products and progressive filling and bridging of the spaces between residual precursor particles. Consequently, the hardened matrix evolved from a porous particle-supported structure containing isolated reaction regions into a compact gel-supported network that contributed to more effective stress transfer within hardened matrix. Among the investigated mixtures, the formulation containing 25% BPPA and 75% GGBFS exhibited a favorable combination of BPPA utilization, processability, and mechanical performance, indicating its potential for further evaluation in coal-mine goaf backfilling applications. Full article

Tibetan-to-English machine translation (MT) models frequently falter under extreme domain data scarcity, often producing translations that violate the distinctive agglutinative rules of Tibetan and suffer from domain-specific stylistic mismatches. To overcome these limitations, we propose Semantic-Syntax Prealignment (SSPA), an innovative corpus generation framework. SSPA constructs high-quality pseudo-parallel pairs by explicitly minimizing the deviation between the syntactic-semantic profiles of generated samples and professional reference texts. Specifically, source-target structural representations are standardized through length-unified truncation and terminology normalization, followed by a dual-domain alignment process that maximizes syntactic cosine similarity under rigorous structural constraints. We further augment these aligned frames via a cross-length dynamic filling mechanism, which is integrated with an Expectation-over-Transformation (EOT)-based style regularization mechanism specifically adapted for stylistic perturbations, to simulate authentic linguistic variations. Extensive evaluations on our newly constructed Tibetan Medicine-Tibetan English (TM-TE) dataset demonstrate that SSPA significantly outperforms existing competitive baselines. Notably, SSPA achieves a BLEU-4 score of 36.2 and improves long-sentence BLEU-4 by 16.8 points, with a parser-verified grammatical compliance rate of 96.2%. The framework exhibits remarkable cross-domain adaptability and stylistic consistency, offering a robust, versatile solution for low-resource Tibetan professional domain MT. Full article

Background: The integration of additive manufacturing (AM) into digital dentistry has extended 3D printing beyond auxiliary applications toward the fabrication of definitive restorations, yet the evidence remains dispersed across diverse materials and technologies. This scoping review aimed to map the available evidence on 3D-printed resin- and ceramic-based materials for definitive tooth-supported restorations, including crowns, fixed dental prostheses, endocrowns, veneers, overlays, and onlays. Methods: The review followed the JBI framework and reported according to PRISMA-ScR. MEDLINE, Embase, and Scopus were searched from inception to April 2026. Two reviewers screened records independently against predefined eligibility criteria, and data were extracted using a piloted charting form capturing study design, materials, additive manufacturing technology, restoration type, and evaluated outcomes. Given the anticipated heterogeneity, extracted data were synthesised descriptively and mapped narratively rather than pooled statistically; 111 studies met the inclusion criteria. Results: The evidence was predominantly in vitro (105 studies), with only six clinical studies, including one randomised controlled trial. Research concentrated on single crowns, zirconia and ceramic-filled/methacrylate-based resins, and vat-photopolymerization technologies. Additively manufactured restorations were frequently reported as comparable to milled controls in dimensional accuracy, marginal and internal fit, and fracture resistance, with values generally falling within the clinically accepted thresholds defined by the primary studies; reported outcomes were most consistent for printed zirconia, whereas printed resins were more often limited by lower strength and colour instability. Outcomes were strongly influenced by processing parameters, underscoring the need for workflow standardisation. Conclusions: The current evidence supports the technical feasibility of 3D-printed definitive restorations more strongly than their long-term clinical durability, highlighting a need for long-term clinical trials. Full article

Direct air capture of CO₂ (DAC) is an emerging engineered carbon removal technology designed to extract CO₂ directly from ambient air and support long-term net-negative emission pathways. Unlike point-source carbon capture, DAC operates under ultradilute CO₂ conditions, where the low partial pressure of CO₂, large air-processing demand, humidity fluctuations, and regeneration energy requirements impose coupled thermodynamic, kinetic, and engineering constraints. While numerous reviews have addressed DAC materials or specific process configurations, a systematic account of how capture performance is progressively lost through the transition from molecular binding to material shaping, contactor operation, regeneration, and final storage remains lacking. This review fills this gap by adopting a performance-transfer framework that bridges capture chemistry, sorbent architecture, contactor engineering, and scalable deployment. We systematically survey the literature of the past decade across capture chemistries, sorbent design principles, structured contactors, regeneration strategies, and system integration, with a focus on studies that report cyclic working capacity, regeneration energy, and material stability under realistic conditions. Rather than enumerating material properties, we analyze the cascading losses introduced at each scale and identify the key bottlenecks limiting net carbon removal. Based on this analysis, we propose a staged roadmap from standardized material reporting to integrated DAC with carbon storage, aiming to guide future research toward verifiable and durable CO₂ removal. Full article