Search Results (208)

Nodular Cast Iron (NCI, also known as ductile iron) is widely used in important components such as crankshafts for automotive engines and internal combustion engines, as well as storage and transportation containers for spent fuel in nuclear power plants, due to its good comprehensive mechanical properties such as strength, toughness, and wear resistance. The effect of temperature on the fracture behavior of NCI was investigated using compact tensile (CT) specimens at different temperatures. The results showed that the conditional fracture toughness parameter (K_Q) of the NCI specimens firstly increased and then decreased with decreasing temperature. The crack tip opening displacement δ_m shows a significant ductile–brittle transition behavior with the decreasing of temperature. δ_m remains constant in the upper plateau region but sharply decreases in the ductile–brittle region (−60 °C to −100 °C) and stabilizes at a smaller value in the lower plateau region. Multiscale fractographic analysis indicated that the fracture mechanism changed from ductile fracture (above −60 °C) to ductile–brittle mixed (−60 °C to −100 °C) and then to completely brittle fracture (below −100 °C). As the temperature decreased, the fracture characteristics changed from ductile dimples to dimple and cleavage mixed and then to brittle cleavage. Full article

This study employs molecular dynamics (MD) simulations to investigate the mechanical response and fracture behavior of penta-graphene, a novel two-dimensional carbon allotrope composed entirely of pentagonal rings with mixed sp²–sp³ hybridization and pronounced mechanical anisotropy. Atomistic simulations are carried out to evaluate the impact of structural defects on mechanical performance and to elucidate crack propagation mechanisms. The results reveal that void defects involving sp³-hybridized carbon atoms cause a more significant degradation in mechanical strength compared to those involving sp² atoms. During fracture, local atomic rearrangements and bond reconstructions lead to the formation of energetically favorable ring structures—such as hexagons and octagons—at the crack tip, promoting enhanced energy dissipation and fracture resistance. A central focus of this work is the evaluation of the critical stress intensity factor (SIF) under mixed-mode (I/II) loading conditions. The simulations demonstrate that the critical SIF is influenced by the loading phase angle, with pure mode I exhibiting a higher SIF than pure mode II. Notably, penta-graphene shows a critical SIF significantly higher than that of graphene, indicating exceptional fracture toughness that is rare among ultra-thin two-dimensional materials. This enhanced toughness is primarily attributed to penta-graphene’s capacity for substantial out-of-plane deformation prior to failure, which redistributes stress near the crack tip, delays crack initiation, and increases energy absorption. Additionally, the study examines crack growth paths as a function of loading phase angle, revealing that branching and kinking can occur even under pure mode I loading. Full article

Despite the promising electronic properties of graphene, its lack of an intrinsic bandgap limits its applicability in semiconductor technologies. This has catalyzed the investigation of newly developed two-dimensional carbon materials, including tetragraphene (TG), a quasi-2D semiconducting material featuring a combination of hexagonal and tetragonal rings. This study aims to investigate the mechanical and fracture behaviors of TG using density functional theory (DFT) and molecular dynamics (MD) simulations, studying two distinct atomic configurations of tetragraphene. DFT simulations assess the mechanical properties, while MD simulations explore the fracture dynamics subjected to mixed mode I (opening mode) and mode II (in-plane shear mode) loading. Our analysis focuses on the influence of loading phase angle, crack edge chirality, crack tip configuration, and temperature on crack propagation paths and critical stress intensity factors (SIFs) in TG structures. Our results show that the critical SIF varies by 12.5–21% depending on the crack chirality. Across all loading conditions, increasing the temperature ranging from 300 K to 2000 K reduces the critical SIF by 10–45%, with the largest reductions observed under pure mode I loading. These outcomes offer important insights into the structural integrity of TG and inform its potential integration into flexible nanoelectronic devices, where mechanical reliability is essential. Full article

Background/Objectives: Previous studies on clear aligner therapy (CAT) in mixed dentition primarily focused on the predictability of maxillary arch expansion. However, limited evidence is available regarding mandibular arch changes, particularly in relation to inter-arch coordination. This study aims to evaluate the effectiveness and predictability of dental expansion in both the upper and lower arches using Invisalign First^® aligners. Methods: A retrospective analysis was conducted with 15 participants. Dental expansions were assessed before and after treatment using iTero intraoral scans processed with 3D analysis software. Measurements were compared to the predicted movements planned in ClinCheck^®. Data normality was verified (Shapiro–Wilk test), descriptive statistics were calculated, and paired t-tests were performed to compare clinical and predicted expansions, with significance set at 0.05. Results: Clear aligners achieved effective dento-alveolar expansion in both arches. Predictability was higher at the cusp level than at the gingival level, indicating a tendency toward tipping movements rather than bodily expansion. The study also highlighted mandibular expansion outcomes and gingival-level discrepancies, providing new insights compared to the previous literature. Minor differences between predicted and achieved movements were observed, partly attributable to natural growth and deciduous tooth exfoliation. Conclusions: Clear aligners are effective in achieving maxillary and mandibular arch expansion in mixed dentition, with good predictability at the coronal level. Overengineering buccal root torque may help promote bodily expansion and reduce cuspal–gingival discrepancies. Further studies with larger sample sizes are needed to optimize treatment planning and predictability. Full article

In response to the high cost and environmental impact of backfill materials in Xinjiang mines, an eco-friendly, large-volume composite was developed by bonding desert-sand mortar to waste concrete. A rock-filled concrete process produced a highly flowable mortar from desert sand, cement, and fly ash. Waste concrete blocks served as coarse aggregate. Specimens were cured for 28 days, then subjected to uniaxial compression tests on a mining rock-mechanics system using water-to-binder ratios of 0.30, 0.35, and 0.40 and aggregate sizes of 30–40 mm, 40–50 mm, and 50–60 mm. Mechanical performance—failure modes, stress–strain response, and related properties—was systematically evaluated. Crack propagation was tracked via digital image correlation (DIC) and acoustic emission (AE) techniques. Failure patterns indicated that the pure-mortar specimens exhibited classic brittle fractures with through-going cracks. Aggregate-containing specimens showed mixed-mode failure, with cracks flowing around aggregates and secondary branches forming non-through-going damage networks. Optimization identified a 0.30 water-to-binder ratio (Groups 3 and 6) as optimal, yielding an average strength of 25 MPa. Among the aggregate sizes, 40–50 mm (Group 7) performed best, with 22.58 MPa. The AE data revealed a three-stage evolution—linear-elastic, nonlinear crack growth, and critical failure—with signal density positively correlating to fracture energy. DIC maps showed unidirectional energy release in pure-mortar specimens, whereas aggregate-containing specimens displayed chaotic energy patterns. This confirms that aggregates alter stress fields at crack tips and redirect energy-dissipation paths, shifting failure from single-crack propagation to a multi-scale damage network. These results provide a theoretical basis and technical support for the resource-efficient use of mining waste and advance green backfill technology, thereby contributing to the sustainable development of mining operations. Full article

This study numerically investigates the solid–liquid mixing characteristics in solid–liquid stirred tanks with solid volume fraction as high as 35%, focusing on the effect of impeller and baffle configurations on solid and liquid flow behaviors. Three stirred tanks with different capacities and impellers were analyzed to evaluate liquid flow field, solid suspension, and free surface profiles. It has demonstrated superior shear rate uniformity in the multi-impeller systems compared to the single-impeller, attributed to the enhanced fluid circulation. Multi-impeller systems can achieve near-complete off-bottom suspension, while the single-impeller configuration exhibited band-shaped particle accumulation above the impeller. Free surface vortices, significantly deeper in the 6 m³ multi-impeller tank due to high blade tip velocities, were mitigated through the integration of four circumferentially arranged triangular baffles. The existence of baffles can suppress surface turbulence, promote axial flow patterns, and eliminate particle accumulation at the tank bottom, improving shear rate and solid concentration homogeneity. These findings provide a beneficial guideline for the optimization of solid–liquid mixing efficiency the similar flow system or processes. Full article

In open-pit bench pre-splitting blasting, the interaction of explosion-induced stress waves between blast holes is essential for safeguarding the rear rock mass. This study utilizes the caustic method to examine the propagation velocity of explosion-induced cracks, the stress intensity factor at the crack tip, and the final morphology of cracks between adjacent blast holes with varying delay times. Field pre-splitting blasting experiments were carried out to validate these effects. The experimental results reveal that, for short inter-hole delay times (0–12 μs), a “hook-like” crack intersection zone emerges between blast holes. Changes in delay time influence the patterns of crack propagation, leading to deviations in the propagation direction of cracks in subsequent blast holes due to the combined effects of stress waves and cracks from preceding holes. The fracture mechanism evolves from pure Mode I (tensile) to a mixed Mode I-II (tensile-shear). Vibration signals from the field blasting tests were analyzed using the variational mode decomposition (VMD) method. The findings indicate that optimized inter-hole delay times can reduce peak particle velocity (PPV) by 18.7–23.4% compared to simultaneous initiation, thereby significantly minimizing damage to the rear rock mass, a crucial factor for maintaining slope stability. Full article

Ginger is an important spice crop in the north-eastern region of India. Rhizome rot, also called soft rot, is one of the most devastating diseases found in ginger that causes yield losses of up to 100% under favourable conditions. Initially, the disease symptoms appear as a light yellowing of the leaf tips that gradually spreads down to the leaf blade of lower leaves and the leaf sheath along the margin. Under favourable environmental conditions, the disease spreads rapidly, potentially causing significant crop damage. The pathogen can infect at any stage of crop growth, and under favourable environmental conditions, the disease spreads rapidly, failing the crop. Current research emphasises mitigating the losses caused by the devastating disease by using management strategies and biocontrol agents (BCAs). Results revealed that the average highest percent rhizome germination, lowest mean disease incidence, lowest mean disease severity index, lowest coefficient of disease index value, highest rhizome yield and benefit–cost ratio were recorded with Trichoderma harzianum (10 g/kg of rhizomes) + soil application of T. harzianum-enriched well-decomposed farm yard manure (3 kg of T. harzianum mixed with 100 kg FYM at 10–15 days before sowing) + soil drenching with T. harzianum at the rate 10 kg/ha, compared to the untreated control. Furthermore, soil chemical properties such as pH, electrical conductivity, soil organic carbon, total available nitrogen, total available phosphorus, and total available potassium play critical roles in rhizome rot disease severity. BCAs can suppress the phytopathogenic fungi and modulate different functions in plants. Full article

Isolation of neurons and glia from the enteric nervous system (ENS) enables ex vivo studies, including the analysis of genomic and transcriptomic profiles. While we previously reported a fluorescence-activated cell sorting (FACS)-based isolation protocol for human ENS cells, no equivalent exists for mice. As directly applying the human protocol to mouse tissue resulted in low recovery of live ENS cells, we optimized tissue dissociation using mouse colons. A 30 min Liberase-based digestion showed optimal recovery of viable ENS cells, with CD56 and CD24 emerging as the most reliable markers to select and subdivide these cells. ENS’ identity was further validated by FACS, using neuronal (TUBB3) and glial (SOX10) markers and reverse transcriptase quantitative PCR on sorted fractions. Overall, the mouse ENS expression profile significantly overlapped with the human one, showing that current dissociation protocols yield a mixed population of enteric neurons and glia. Nonetheless, using the imaging flow cytometer BD S8 FACS Discover and ELAVL4 as a neuronal soma-associated marker, we observed enrichment of neurons in a CD56/CD24^TIP population. In conclusion, we present here a protocol for high-purity FACS-based isolation of viable mouse ENS cells, suitable for downstream applications. Full article

Background: Meta-analyses on the prevalence and significance of thyroid incidentalomas at PET (TIP) are available only about [¹⁸F]FDG. Focal TIP at [¹⁸F]FDG PET is not rare and may be malignant lesions in about one-third of cases. The aim of this study is to perform a meta-analysis on the prevalence and clinical significance of TIP using other PET radiotracers beyond [¹⁸F]FDG. Methods: A comprehensive literature search of studies about TIP was carried out using four different databases, screened until 31 December 2024. Only original articles about TIP using radiopharmaceuticals other than [¹⁸F]FDG were selected. A proportion meta-analysis on the prevalence and clinical significance of TIP was carried out on a patient-based analysis using a random-effects model. Results: 21 studies (29,409 patients) were included in the meta-analysis. PET was performed using radiolabeled somatostatin analogues (SSA) [n = 5], choline [n = 6], prostate-specific membrane antigen (PSMA) [n = 7], or fibroblast activation protein inhibitors (FAPI) [n = 3]. The uptake pattern of TIP was described as focal, diffuse, or mixed/heterogeneous. The pooled prevalence of TIP was 5.6% for SSA-PET, 6.1% for choline-PET, 4.2% for PSMA-PET, and 3.6% for FAPI-PET. The final diagnosis of TIP with a diffuse pattern was a benign condition or represented a physiological uptake. Conversely, TIP with focal or mixed/heterogeneous pattern may represent a benign condition in most cases, but even a malignant lesion in 6–10% of cases. Conclusions: As for [¹⁸F]FDG, TIP using other radiopharmaceuticals is not rare. Most of them are benign, but those with focal or heterogeneous uptake patterns may represent a malignant lesion in some cases (even if the risk of malignancy is lower compared to [¹⁸F]FDG PET), thus requiring further evaluation. Further studies are warranted to better clarify the clinical impact of TIP detection. Full article

When testing the output of piezoelectric devices under different pressures, the friction between the pressure platform and the device causes a large amount of frictional electrical signals to be mixed in the output piezoelectric signal, seriously affecting the measurement accuracy of the piezoelectric signal. The current solution is to encapsulate the contact interface with identical materials to suppress triboelectric interference. However, this work has shown that even when contact separation is implemented at the interface of same media, triboelectric signals can still be generated. The heterogeneous potential distribution of the same material in contact separation has been discovered for the first time through the contact interface potential distribution, proving that charge transfer still exists between the same materials. Atomic force microscopy (AFM) was used to analyze the microstructure of the interface, and it was found that the existence of the surface tip structure would enhance the electron loss. Based on this, a new electron transfer model for surface–tip electron cloud interaction is proposed in this work. In addition, by comparing the output voltage characteristics of the triboelectric nanogenerators (TENGs) of seven polymer materials (e.g., polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyimide (PI), and polyethylene terephthalate (PET)), it was found that the open circuit voltage of PP material was only 0.06 V when they friction with each other, which is 2–3 orders of magnitude lower than other materials. When PP materials are applied to the package of piezoelectric devices, the precision of piezoelectric output characterization can be improved significantly, and a new experimental basis for a triboelectric theory system can be provided. Full article

Objectives: Trauma to maxillary incisors is frequent, and requires timely, conservative management for optimal prognosis. This in vitro study evaluated the fracture resistance (FR) and orthodontic bracket bond strength (BS) of incisors following incisal fragment reattachment using various restorative techniques. Materials and Methods: Two independent tests—FR testing (Newtons) and BS testing (megapascals)—were conducted. Eighty intact human maxillary central incisors (n = 40/test), standardized in size and shape using a digital caliper (Mitutoyo, ±0.01 mm), were embedded in acrylic resin and numbered. An uncomplicated crown fracture was induced in 64 teeth (n = 32/test), and the teeth were randomly assigned (simple randomization using Excel’s RAND function) to five groups (n = 8/group/test): (1) intact teeth (negative control, NC); (2) nanohybrid composite buildup using Filtek Z250 and Single Bond 2 (positive control, CB); (3) fragment reattachment using flowable composite (Filtek Supreme, FL); (4) reattachment with a palatal veneer using a nanohybrid composite (PV); and (5) reattachment reinforced with a polyethylene fiber band (Ribbond Inc., RB). In BS testing groups, stainless steel orthodontic brackets (PINNACLE) were bonded using Transbond XT, centered over the fracture line. Light curing was performed using an LED unit (Mini LED Standard, Acteon, 1250 mW/cm², 20 s/bond, 40 s/composite, 2 mm curing tip distance). Specimens were stored in distilled water at room temperature for 24 h before reattachment. FR and BS were evaluated using a universal testing machine (Instron) until failure. Failure modes were analyzed, and data were statistically evaluated using one-way ANOVA, Tukey’s post hoc test, and Pearson’s correlation analysis. Results: Significant differences were observed among groups for both FR and BS (p < 0.05). The NC group exhibited the highest FR (514.4 N) and BS (17.6 MPa). The RB group recorded the second-highest FR (324.6), followed by the PV (234.6), CB (224.9), and FL (203.7) groups. The CB group demonstrated the second-best BS (16.6), followed by the RB (15.2), FL (13.4), and PV (6.5) groups. FR and BS were negatively correlated. Mixed failures predominated in the reattachment groups, except for the PV group, which showed mainly adhesive failures. In BS testing, mixed failures dominated in the NC and CB groups, while adhesive failures predominated in the PV and FL groups. Conclusions: Ribbond reinforcement improves the mechanical performance of reattached incisal fragments, and composite buildup may provide more reliable bracket bonding than fragment reattachment. Clinical Relevance: In cases where biomimetic, minimally invasive reattachment is indicated, Ribbond fiber reinforcement appears to offer a reliable restorative solution. Full article

Thermal Integrity Profiling (TIP) effectively monitors concrete integrity. TIP detects structural defects and locates them through anomalies in hydration–temperature curves. However, TIP alone cannot accurately identify the defect types. To resolve this limitation, strain monitoring is integrated with TIP. A dual-parameter temperature–strain monitoring system using fiber-optic sensing was implemented in a diaphragm wall of Weizishan Station, Jinan. This study investigated the spatial distribution and variation patterns of concrete temperature–strain during the different stages of hydration. A thermal–mechanical–chemical multi-field coupling model was established based on the concrete mix ratio and the theoretical thermal parameters, and its feasibility was verified. This study also analyzed the impact mechanisms of four defect types—voids, mud inclusions, necking, and widening—on the surrounding concrete’s heat release and deformation during hydration. It presents specific hydration–temperature–strain characteristic curves that can accurately differentiate the defect types and established the correspondence between the defect types and these characteristic patterns. Finally, a rapid and accurate defect identification process is proposed for practical application, improving efficiency and precision in detecting anomalies. The findings provide a reference for implementing appropriate defect prevention and remediation measures on-site and hold promise for enhancing the prediction and control of defects during the hydration period of concrete structures. Full article

Previous research and classroom practices have focused on dispelling shame, assuming that it negatively impacts self-efficacy and performance, and overlook the potential for shame to facilitate learning. To investigate this gap, we designed an intervention with 132 tertiary education students (45.46% male, 64.4% European ethnicity) spanning diverse undergraduate majors to show how and why designing for experiences of shame and appropriately regulating them can differentially impact learning. Shame was induced through autobiographical recall, imagination, and failure-driven problem-solving before randomly assigning students to three conditions: two with explicit tips for either decreasing shame or maintaining shame (experimental groups) and one with no-regulation tips (control). Students worked on an introductory data science problem deliberately designed to lead to failure before receiving canonical instruction. Manipulation checks triangulating self-reported and facial expression analysis data suggested that shame was successfully regulated in the intended direction, depending on the condition. Our results, drawing on mixed-methods analyses, further suggested that relative to students decreasing shame, those who maintained shame during initial problem-solving had (i) similar post-test performance on a non-isomorphic question and improved performance on the transfer question, evidenced by accuracy in solving applied data science and inference tasks; (ii) complete reasoning across all post-test questions, as evidenced by elaborations justifying the usage of graphical and numerical representations across those tasks; and (iii) use of superior emotion regulation strategies focused on deploying attention to the problem and reappraising its inherently challenging nature with an approach orientation, as evidenced by a higher frequency of such codes derived from self-reported qualitative data during the intervention. Decreasing shame was as effective as not engaging in explicit regulation. Our results suggest that teaching efforts should be channeled to facilitate experiencing emotions that are conducive to goals, whether they feel pleasurable or not, which may inevitably involve emoting both positive and negative (e.g., shame) in moderation. However, it is paramount that emotional experiences are not merely seen by educators as tools for improved content learning but as an essential part of holistic student development. We advocate for the deliberate design of learning experiences that support, rather than overshadow, students’ emotional growth. Full article

A competition experiment between Vachellia gerrardii and invasive Nicotiana glauca Graham was conducted to assess the impact of Arbuscular Mycorrhizal Fungi (AMF) symbiosis on the inter and intraspecific competition between the two species. Seedlings were established under mono and mixed plantations with different species proportions (3:1, 2:2, 1:3) and plant densities (1, 2, 3, and 4 plants/pot) for mixed and mono planting respectively, with and without AMF. The vegetative growth parameters (height, leaf area and number, total dry weight/plant, relative yield, relative yield total), roots characteristics (length, surface area, volume, tips number), competitive interaction (aggressivity), and physiological traits (chlorophyll a, chlorophyll b, photosynthesis, stomatal conductance) were measured to evaluate plant responses to AMF symbiosis and competition. The results revealed that AMF symbiosis significantly enhanced the vegetative parameters (leaf area, height, and total dry weight) in both species under mono and mixed plantations compared to plants without AMF. Under AMF treatment, in the interspecific competition, most vegetative and root parameters of N. glauca were higher than V. gerrardii. At inoculant and species proportions, the relative yield of N. glauca exceeded that for V. gerrardii; however, N. glauca was more aggressive towards V. gerrardii. N. glauca root indices were higher than V. gerrardii under inter and intraspecific competition. Simultaneously, for both species, in monoculture plantations, most parameters decreased as plant density increased, wherein the decrease was higher for plants grown without AMF. Photosynthesis increased in AMF treatment, particularly for N. glauca. In conclusion, AMF promoted the growth of invasive N. glauca more than native V. gerrardii, particularly in terms of the root system. Our results provide a critical perspective that the AMF has the potential to contribute and facilitate the invasion of N. glauca, as well as support it with a competitive advantage over V. gerrardii, thus highlighting its potential role in shaping plant–plant interaction in invaded habitats. Full article