Search Results (1,557)

Vibration test fixtures are widely used to evaluate the dynamic characteristics of structures. However, their performance is often limited by their excessive weight and unintended resonances. Conventional optimization methods, such as genetic algorithms, have been applied to improve fixture design; however, they often require considerable computational effort and are inefficient for problems involving discrete design variables. To address these limitations, this study proposes a rib thickness optimization method based on an orthogonal array. The novelty of the proposed method lies in the introduction of an influence value that simultaneously reflects lightweighting effect and first natural frequency change. The proposed method generates orthogonal arrays for rib-thickness configurations, performs modal analyses, and applies analysis of means based on this influence value to identify ribs with low structural influence for thickness reduction. Its effectiveness was validated through comparison with a genetic algorithm under identical conditions. The results showed that the orthogonal array achieved rib reduction patterns similar to those of the genetic algorithm while requiring only 0.84% of the analyses and 1.14% of the computation time required by the genetic algorithm. These findings demonstrate that the orthogonal array provides an efficient and practical alternative for rib thickness optimization in vibration test fixtures. Full article

This paper presents a theoretical approach based on the FSDT to study the acoustic vibration performance of rib-stiffened PVC foam sandwich structures with reinforcing and weakening phases when submerged in water. The complex core layer with reinforcing and weakening phases is homogenized to an equivalent orthotropic layer. Building upon this framework, the governing equations of motion for rib-stiffened PVC foam sandwich structures under the boundary conditions of a simply supported type are derived, incorporating the coupling interaction between the reinforcing ribs and the sandwich plates. Considering the influence of the underwater environment, with the Helmholtz equation governing the continuity of the acoustic pressure field and the Euler equation regulating the fluid–structure interaction interface continuity, the Navier method is subsequently employed to solve for the natural frequencies and acoustic vibration responses. For the purpose of verifying the proposed approach, the predicted results are contrasted with both the literature-derived data and numerical simulation results. Finally, parametric research is further conducted to explore the effect of the parameters of the rib and core layers on the underwater acoustic vibration characteristics. The conclusions drawn from this study can provide meaningful guidance for engineering design and optimization of such rib-stiffened sandwich structures, incorporating both reinforcing and weakening phases in underwater engineering applications. Full article

Background: Traumatic hemothorax is a common complication of blunt chest trauma and remains associated with significant morbidity and mortality. Although contrast-enhanced computed tomography (CT) is central to diagnosis, the optimal criteria for selecting patients who require invasive management versus conservative treatment remain unclear. This study aimed to evaluate the management strategies and clinical outcomes of traumatic hemothorax and to identify predictors of surgical intervention and postoperative complications. Methods: We conducted a retrospective, single-center cohort study including adult patients admitted to a Level II Emergency Department with hemothorax following blunt chest trauma between January 2019 and December 2024. Primary outcomes were the need for urgent chest drainage or surgery. Secondary outcomes included postoperative complications, length of hospital stay, and intensive care unit admission. Univariable and multivariable regression analyses were performed to identify factors associated with surgical intervention and complications. Results: Seventy-two patients were included (mean age 60.0 ± 20.5 years; 80.6% male). Rib fractures were the most common cause of hemothorax (61.1%). Chest tube placement was required in 70.8% of cases, and 31.9% underwent urgent surgical intervention. Active bleeding on contrast-enhanced CT was identified in 16.7% of patients and was the only independent predictor of urgent surgery (OR 3.85, 95% CI 1.07–13.88; p = 0.039). The initial volume of blood drained after chest tube insertion did not differ between surgically and non-surgically managed patients. Conservative management was successful in 19.4% of cases. Postoperative complications occurred in five patients and were associated with a higher comorbidity burden. Overall mortality was 5.6%. Conclusions: In traumatic hemothorax following blunt chest trauma, active bleeding on contrast-enhanced CT seems to be the strongest predictor of urgent surgical intervention, whereas initial pleural drainage volume alone is not. Conservative management is safe in selected patients, while comorbidities influence postoperative outcomes. Multidisciplinary management and accurate radiological assessment are essential to guide timely and appropriate treatment. Full article

In order to study the stability of orthotropic steel box girders and the characteristics of the synergistic stress mechanism of key components, the test method of axial compression using the scale model of steel box girder segments was carried out, and the collaborative working performance of the plate ribs of the U-shaped stiffener plate and the influence mechanism of the diaphragm on the structural stability were systematically studied. The results show that the strain difference between the deckplate and the U rib increases significantly with the increase in load, and the distribution law of the end chamber is larger than the middle, and the bottom plate is larger than the top plate and the web plate. The diaphragm mainly bears the tensile force under axial load, which provides out-of-plane restraint for the stiffener, and its restraint effect is the strongest at the web plate and the weakest at the bottom plate. This paper clarifies the synergistic stress mechanism of U-rib stiffeners under high axial pressure conditions, quantifies the contribution of diaphragms to local stability, and provides a theoretical basis for the structural design of similar bridges. Full article

Bud sport mutations are valuable sources of citrus germplasm innovation and provide an ideal system to dissect genetic regulation of specific traits. The Ponkan mandarin (Citrus reticulata Blanco cv. Ponkan) bud sport mutant “Pumpkin mandarin” displays a Pumpkin-shaped, ribbed peel protrusion phenotype with elevated soluble sugars, but its molecular basis remains unclear. Here, wild-type Ponkan (PG) and Pumpkin mandarin (NG) were compared across six developmental stages (90–240 days after flowering, DAF) for fruit appearance and internal quality, peel firmness, and tissue morphology; RNA-seq was performed on mature peel at 240 DAF. Peel protrusion was detectable as early as flowering. NG showed significantly lower mature fruit weight and consistently higher soluble sugar content throughout development. Peel firmness exhibited a stage-dependent reversal: NG exceeded PG before 180 DAF, PG exceeded NG at 180–210 DAF, and NG again exceeded PG at 240 DAF. RNA-seq generated 41.38 Gb of high-quality data and identified 580 differentially expressed genes (DEGs; 411 upregulated, 169 downregulated). DEGs were enriched in cell wall organization/modification, phenylpropanoid biosynthesis, starch and sucrose metabolism, cutin/wax biosynthesis, and photosynthesis. Expansin (EXP) and GH18 genes were upregulated, while NAM genes encoding NAC transcription factors were downregulated, suggesting an imbalance between cell wall loosening and structural maintenance in protrusion formation. Peel DEGs also included upregulated sucrose synthase (SUS) and sugar transporter (SUT) genes, indicating carbohydrate-related reprogramming in mutant peel. We propose a preliminary network in which NAM may function upstream, cell wall remodeling represents a principal effector module, and the peel carbohydrate metabolism acts as an accompanying module. Full article

Enhancing the vibroacoustic performance of underwater vehicles remains a critical challenge in marine engineering. Increasing geometric stiffness is a conventional strategy to suppress vibration, yet its effectiveness in reducing underwater sound radiation can be practically limited. This paper presents a numerical investigation of the vibroacoustic response of composite grillage sandwich structures, with a focus on separating the contributions of geometric stiffening and core damping. A coupled acoustic structural model is developed based on the equivalent single layer theory and implemented in a finite element framework, then validated against analytical benchmark solutions. The parametric study reveals a stiffness saturation phenomenon in the acoustic domain. Although increasing rib height significantly reduces the mean square velocity, the radiated sound power reaches a saturation plateau and can even show a slight rebound at higher frequencies. This behavior is attributed to an increase in structural phase velocity that shifts modal components toward a more efficient radiation regime, thereby increasing radiation efficiency. To address this limitation, the damping modulation role of the core material is examined. The results show that introducing a high damping core into the grillage skeleton suppresses broadband noise and resonance peaks, without a comparable rise in radiation efficiency that may accompany geometric stiffening. The study indicates that a hierarchical synergistic design strategy that uses geometric stiffness for load bearing and low frequency control, while leveraging core damping to mitigate the acoustic saturation limit, provides useful physical insight into more efficient noise control approaches than purely stiffness based approaches. Full article

Introduction and Importance: Colorectal adenocarcinoma typically metastasizes to the liver and lungs, with pleural, breast, or osseous involvement being exceedingly rare. Here, we report an unusual case of rectal adenocarcinoma metastasizing to the chest wall with simultaneous involvement of the lung, pleura, ribs, and subcutaneous breast tissue, forming a dominant giant metastasis (25 × 18 × 16 cm) accompanied by additional satellite lesions between the ribs and pectoral muscles, as well as intrapulmonary nodules. Presentation of case: The patient underwent radical resection including rib excision, followed by hyperthermic intrathoracic chemotherapy (HITHOC) with mitomycin. Chest wall integrity was restored using a synthetic mesh and titanium plating, ensuring both oncologic clearance and structural stability. Multimodal therapy also included neoadjuvant chemotherapy with bevacizumab, which was continued postoperatively. Clinical discussion: This case underscores the critical role of a multidisciplinary strategy in managing rare and aggressive metastatic patterns of colorectal cancer. In selected patients, a combination of systemic therapy, extensive surgical resection, advanced reconstruction, and regional chemotherapy may offer the potential for short-term local disease control. Conclusions: The radical excision of the giant tumour enabled continuation of systemic therapy under the national drug programme, was associated with short-term local control, and improved the patient’s quality of life. Full article

Aim: Insertion of a chest drain in a newborn infant is a procedure commonly performed in an emergency setting. There are no commercially available neonatal chest drain insertion simulation models. We aim to build an inexpensive and realistic model. Methods: A discarded Laerdal Newborn manikin was modified with an internal rib cage, obtained from a decorative Halloween child skeleton. A synthetic silicone layer was used as a subcutaneous tissue and a resealable snack bag as lungs. This cost approximately $110 AUD. Medical staff were invited to use the manikin for chest drain insertion using a Safe-T centesis device. Results: Thirty medical officers (50% were registrars and the rest senior medical officers) participated in the study. Fidelity was rated high and there was no difference in the reported aesthetics, tactility, location of anatomy, ease of drainage of air or fluid amongst the registrars, fellows or neonatal consultants. Conclusions: It is feasible to build a realistic, high-fidelity manikin for newborn chest drain insertion. The use of a low-cost high-fidelity chest drain model needs to be evaluated in further studies. Full article

The Draa Sfar polymetallic mine, located near Marrakech in Morocco, represents the deepest currently operating underground mine in North Africa, with workings extending beyond depths of −1200 m. At such depths, mining activities are conducted within weak, highly anisotropic foliated black pelites, where recurrent instability mechanisms, most notably rib buckling and crown deterioration, are frequently observed, especially in drifts developed parallel to the foliation planes. In this context, the present study integrates detailed structural field observations with two-dimensional finite-element modelling using RS2 in order to analyse excavation-scale stability within these schistose pelitic rocks. Both numerical simulations and field evidence indicate that increasing depth-related confinement, together with a dominant in situ stress regime, favours stress channelling and localized damage development, while the pronounced transverse weakness of the pelites exerts a primary control on failure kinematics, including schistosity-parallel spalling, asymmetric rib buckling, and shear along inclined foliation intersecting the excavation back. Instability processes are further intensified by excavation geometry and mine layout: angular, square-shaped profiles and foliation-parallel drift orientations generate steeper stress gradients and greater convergence compared to arched sections, while proximity to stopes and adjacent openings enhances mining-induced stress redistribution and associated deformation. Intersection areas emerge as the most critical configurations, where the superposition of stress perturbations and structurally controlled damage mechanisms accelerates wall convergence and roof sagging. Overall, these findings demonstrate that drift stability cannot be adequately evaluated using generic design criteria when excavation geometry, interaction effects, and structural anisotropy exert a dominant influence on mechanical behaviour. Consequently, a fully integrated approach that combines drift geometry optimisation, detailed structural mapping, site-calibrated numerical modelling, and in situ monitoring is required to achieve reliable stability assessment and control. Full article

The integration of glass fibre-reinforced polymer (GFRP) and steel reinforcement in hybrid RC beams offers durability benefits, yet the specific influence of GFRP surface treatments on bond mechanics remains critical. This study experimentally investigates the performance of hybrid GFRP-steel-reinforced beams under three-point bending, comparing sand-coated and ribbed GFRP bars, while maintaining a constant total reinforcement ratio of 1.4% to isolate interface mechanics. Due to the exploratory nature of the study and the specific specimen matrix, the results are interpreted as observed experimental trends rather than statistically generalised performance metrics. The results indicate that ribbed GFRP bars provide enhance mechanical interlocking; in this specific experimental program, the ribbed GFRP hybrid beam exhibits an observed load capacity approximately 11% greater than the sand-coated specimen in this study and surpassing comparable steel-only beams. Additionally, ribbed configurations demonstrated an observed 15% higher toughness. In contrast, sand-coated hybrid beams exhibited signs of premature bond degradation, quantitatively captured by strain gauge monitoring; sand-coated bars plateaued at 14,000 µε, reaching only 79% of their theoretical rupture capacity. This strain limitation indicates failure by internal slippage rather than material rupture, further evidenced by a 50% reduction in crack propagation compared to ribbed beams. While energy-based ductility indices suggest a marginal 6% advantage for sand-coated bars, both hybrid systems exhibited relatively low energy-based ductility indices (μ < 2), reflecting the linear-elastic nature of GFRP reinforcement. These findings suggest that the mechanical interlock of ribbed surface treatments is more resilient under the combined stress states typical of hybrid configurations, providing a foundational baseline for the development of future numerical models and reliability-based design frameworks for hybrid GFRP-steel-RC systems. Full article

Anisogrid lattice structures are gaining increasing attention due to their high strength-to-weight ratios, which make them ideal for the production of lightweight mechanical components. This study presents a finite element model developed to evaluate stress distribution in an anisogrid sandwich panel with an octahedral core. The Taguchi method and analysis of variance (ANOVA) were employed to identify the geometric parameters that mostly influence the stress state and, consequently, the structural strength. The radius of the inclined ribs and the thickness of the skins were identified as the most critical factors, while the influence of the horizontal rib cross-sectional area was found to be minimal. The stiffness and strain energy of different cell geometries were also evaluated, and the results are consistent with the stress-based analysis. These findings offer valuable guidance for optimizing anisogrid geometry, improving load-bearing performance and advancing the design of high-efficiency structures. Full article

To address the challenges encountered during the in situ welding reinforcement process of hollow spherical joints, including complex construction, limited quality control, and low efficiency, this study proposed a prefabricated reinforced hollow spherical joint. A three-dimensional finite element (FE) model was developed and validated against experimental results to quantify the effects of T-rib web width (b), web thickness (t₁), ferrule thickness (t₂), hollow-sphere diameter (D), and bolt pretension (f_v) on the bearing capacity of the prefabricated joint. Based on these analyses, a predictive model was established for the axial compressive bearing capacity of the prefabricated joint. The results showed that, under compression, the reinforcing components primarily provided a supporting role to the hollow sphere, thereby improving the buckling resistance of the prefabricated joint under compression. The reinforcement mechanism primarily relied on friction between the ferrule and the steel stub for load transfer, with the available frictional resistance governed primarily by bolt pretension and the stiffness of the reinforcing components. When sufficient friction existed between the ferrule and the steel tube, increasing the T-rib web width from 0 mm to 80 mm improved the bearing capacity of the prefabricated joint by 33%. At a T-rib flange height (h)-to-web width ratio of h/b = 1.0, the T-rib satisfied the reinforcement requirement through its inherent strength and stiffness. As the hollow-sphere diameter-to-thickness ratio decreased, the incremental gain in bearing capacity diminished. A predictive model was proposed for compressive bearing capacity by accounting for the support provided by the reinforcing components and the effects of hollow-sphere diameter, steel-tube diameter, and the tube-to-sphere diameter ratio. The proposed model predicted the FE results with errors within ±10%, and the findings can provide a practical reference for designing the compressive bearing capacity of prefabricated reinforced hollow spherical joints. Full article

This study investigates the screw withdrawal resistance (SWR) of hollow wood–plastic composite (WPC) door frames, which serve as moisture-resistant alternatives to traditional wood-based materials. The tested WPC, characterised by a density of 1.33 g/cm³ and a polymer-bound lignocellulosic filler, exhibits superior dimensional stability and low water absorption—under 4% after 24 h of immersion. The research focuses on how the unique chambered geometry of these industrial profiles affects the anchoring of 20 mm conical wood screws used to mount essential fittings such as hinges and lock catches. The SWR was determined using a universal testing machine in accordance with the modified EN 320 standards. Results indicate that the installation location within the profile significantly dictates load-bearing capacity: the band profile (lock catch) achieved an average SWR of 525.65 N, while the beam profile (hinge) averaged only 275.25 N. This performance gap arises because screws anchor only into internal “ribs” rather than the full material depth. Since these values are considerably lower than those of traditional particleboard (~1364–1775 N), the study highlights a critical need to optimise screw dimensions to ensure the structural stability and safety of hollow WPC door systems. Full article

Ultrasound enables radiation-free longitudinal monitoring of scoliosis, but rib shadowing and speckle noise often obscure vertebral structures. Current deep-learning methods present results in terms of localisation accuracy, without directly measuring anatomical completeness. We introduce a vertebra-level completeness model that includes a YOLO-based detection framework and an explicit representation of completeness, the Vertebra Presence Matrix (VPM). The VPM provides visibility into detections across 17 ordinal vertebral levels (T1–T12, L1–L5), allowing us to measure completeness across anatomy rather than just detections. Thoracolumbar ultrasound scans were annotated and divided into train/test sets using a patient-wise split to avoid data leakage. Four model variants were evaluated, including full-spine and vertebra-centric crop representations with single-class and 17-class detection heads. The full-spine detector was less stable in regions of high anatomical variability, such as the upper thoracic and lower lumbar spine. Crops of individual vertebrae were more stable under partial fields of view. The 17-class crop model achieved an mAP50 of 0.929 and a scan-level completeness score of 0.74 using the VPM. These results demonstrate that vertebral completeness can be explicitly quantified and integrated with localisation-based metrics for completeness-aware automated scoliosis evaluation. Full article

(1) Background: Idiopathic scoliosis is a three-dimensional deformity, yet clinical and research decision-making still relies largely on radiographic Cobb angle measurements. As a radiation-free alternative, clinical assessment of transverse and sagittal plane deformities has gained importance. This study evaluated the concurrent validity and intra- and interrater reproducibility of continuous measurements of rib hump, thoracic kyphosis, and lumbar lordosis obtained using a smartphone application in adolescents with spinal deformities. (2) Methods: Adolescents aged 10–17 years with scoliosis (>10° Cobb) or hyperkyphosis (>50° Cobb) were recruited. Continuous measurements of angle of trunk rotation (ATR) during the Adams forward bend test and in standing position, as well as sagittal profile, were collected using the ISICO app mounted on a standardized plastic tool. Concurrent validity was assessed against a scoliometer using Spearman correlation, root mean square error, and Bland–Altman analysis, while reproducibility was evaluated using intraclass correlation coefficients, standard error of measurement, and minimal detectable change. (3) Results: Thirty-two adolescents were included for validation and intrarater analyses and 34 for interrater analyses. ATR measured during the Adams test showed very high correlation with the scoliometer and minimal bias, while standing ATR showed moderate correlation. Reliability was excellent for rib hump during forward bending and moderate for sagittal parameters, with the lowest values observed for lumbar lordosis. (4) Conclusions: These findings support the clinical use of continuous app-based ATR assessment and suggest that sagittal measurements may be useful with appropriate examiner training. Full article