Search Results (85)

The cast nickel-based superalloy K417G exhibits excellent high-temperature strength, but non-equilibrium solidification during casting can cause defects such as irreparable interdendritic microporosity, which significantly degrades its fatigue and creep properties. This study uses hot isostatic pressing (HIP) to eliminate internal flaws such as porosity in the K417G alloy, aiming to improve its mechanical properties. We investigated the microstructure and mechanical properties of K417G under two thermal conditions: solution heat treatment (SHT) and hot isostatic pressing (HIP). The results indicate that HIP significantly reduces microporosity. Compared to SHT, HIP improves the mechanical performance of K417G. The creep fracture mechanism shifts from intergranular brittle fracture (SHT) to ductile fracture (HIP). Consequently, HIP increases the alloy′s creep life approximately threefold and raises its fatigue limit by about 20 MPa. This improvement is attributed to pore density reduction, which decreases stress concentration zones and homogenizes the microstructure, thereby impeding fatigue crack nucleation and extending the crack incubation period. Full article

From the point of view of the intelligent operation and maintenance of high-speed train tracks, this paper examines the research status of high-speed train rail damage detection technology in the field of high-speed train track operation and maintenance detection in recent years, summarizes the damage detection methods for high-speed trains, and compares and analyzes different detection technologies and application research results. The analysis results show that the detection methods for high-speed train rail damage mainly focus on the research and application of non-destructive testing technology and methods, as well as testing platform equipment. Detection platforms and equipment include a new type of vortex meter, integrated track recording vehicles, laser rangefinders, thermal sensors, laser vision systems, LiDAR, new ultrasonic detectors, rail detection vehicles, rail detection robots, laser on-board rail detection systems, track recorders, self-moving trolleys, etc. The main research and application methods include electromagnetic detection, optical detection, ultrasonic guided wave detection, acoustic emission detection, ray detection, vortex detection, and vibration detection. In recent years, the most widely studied and applied methods have been rail detection based on LiDAR detection, ultrasonic detection, eddy current detection, and optical detection. The most important optical detection method is machine vision detection. Ultrasonic detection can detect internal damage of the rail. LiDAR detection can detect dirt around the rail and the surface, but the cost of this kind of equipment is very high. And the application cost is also very high. In the future, for high-speed railway rail damage detection, the damage standards must be followed first. In terms of rail geometric parameters, the domestic standard (TB 10754-2018) requires a gauge deviation of ±1 mm, a track direction deviation of 0.3 mm/10 m, and a height deviation of 0.5 mm/10 m, and some indicators are stricter than European standard EN-13848. In terms of damage detection, domestic flaw detection vehicles have achieved millimeter-level accuracy in crack detection in rail heads, rail waists, and other parts, with a damage detection rate of over 85%. The accuracy of identifying track components by the drone detection system is 93.6%, and the identification rate of potential safety hazards is 81.8%. There is a certain gap with international standards, and standards such as EN 13848 have stricter requirements for testing cycles and data storage, especially in quantifying damage detection requirements, real-time damage data, and safety, which will be the key research and development contents and directions in the future. Full article

The density of SLMed (Selective Laser Melting) Ti-22Al-25Nb alloy was improved through hot isostatic pressing (HIP) treatment, and the influence of HIP and solution aging on the microstructure of Ti-22Al-25Nb alloy in the as-deposited state was examined. The results indicate that following (1100 °C + 300 MPa)/3 h-HIP, the specimen densities have risen to 99.71%, porosity has markedly decreased, and internal flaws have been eradicated. Microstructural analysis reveals a significant presence of GBα₂ (GB, Grain Boundary) along grain boundaries, with GBLO + α₂ (GBL, Grain Boundary Lath; O, Orthorhombic) laths extending parallel from the grain boundaries into the intragranular region. Additionally, a limited number of cross or snowflake O + α₂ lath clusters and acicular O phases are precipitated within the B2 (B, Body-centered cubic) phase in the HIPed state, characterized by isotropic and linear grain boundaries. The GBLα₂ and GBLO exhibit two growth modes: sympathetic nucleation and interfacially unstable nucleation. During the solid solution treatment following HIP, as the solid solution temperature rises, the acicular O phase, GBLO, lath O phase, lath α_2, and GBα₂ sequentially dissolve, increasing the volume fraction of the B2 phase. After HIP, the aging microstructure is primarily characterized by the proliferation of the acicular O phase precipitated from the B2 phase and retaining the lath O phase in a solid solution. The precipitation of GBLO in the original solid solution is suppressed, and the GBLα₂ in the original solid solution partially decomposes into rimO, resulting in coarse grain size and significant internal decomposition of α₂. Following solution treatment and aging at 920 °C, the proliferation of the acicular O phase enhances ductility, resulting in ideal overall characteristics with a yield strength (YS) of 760.81 MPa, ultimate tensile strength (UTS) of 869.32 MPa, and elongation (EL) of 2.683%. This study demonstrates that the HIP treatment and the modification of solution aging parameters can substantially increase the density and refine the microstructure of Ti-22Al-25Nb alloy, hence enhancing its mechanical properties. Full article

According to ontological addiction theory, the root cause of mental suffering is a dysfunctional conceptualisation of the self. Typically, an individual with such a flawed self-concept deems themselves to be intrinsically separate from their surroundings, with their beliefs, choices and behaviours structured in order to reinforce their sense of an independently existing self. The Ontological Addiction Scale (OAS) was developed to measure ontological addiction and demonstrates good psychometric properties for the original version validated in English. The present study aimed to validate a French language version of the OAS. The 24-item OAS was administered to 492 French adults with emotional and/or mood disorders. The French OAS demonstrated good internal consistency (Cronbach’s alpha: 0.89) and strong test–retest reliability. We suggest a single-factor structure, aligning with the original English version. The 12-item OAS also showed good internal consistency (Cronbach’s alpha: 0.81). Construct validity was confirmed by medium to large correlations with self-esteem, shame, perfectionism and mindfulness. These results support the use of the French OAS in research and clinical practice, offering a robust measure for assessing ontological addiction as well as a dimensional assessment of psychiatric symptoms. Full article

Nociplastic pain, commonly observed in conditions such as Fibromyalgia, chronic fatigue syndrome, and irritable bowel syndrome, arises from altered central pain processing and involves complex mechanisms, including interactions between the gut–brain axis and immune dysregulation. Conventional therapies often fail to address this type of pain effectively, leading to interest in alternative approaches such as fecal microbiota transplantation. This technique has been proposed to restore gut microbial balance and modulate systemic inflammation, neuroinflammation, and neurotransmitter signaling. This systematic review, conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and registered in the International Prospective Register of Systematic Reviews (CRD42024611939), evaluated 13 studies with n = 409 participants, including clinical trials, case reports, and retrospective analyses. A quality assessment was performed using appraisal tools such as Cochrane RoB 2, ROBINS-I, NOS, and CARE. The results suggest that fecal microbiota transplantation may reduce pain intensity and improve fatigue and quality of life, particularly in patients with Fibromyalgia and irritable bowel syndrome. However, outcomes for Chronic Fatigue Syndrome and psoriatic arthritis were inconsistent and limited by methodological flaws, small sample sizes, and variability in protocols and donor selection. Although adverse events were minimal, the current evidence is insufficient to support widespread clinical use. High-quality, standardized studies are needed to confirm the efficacy of fecal microbiota transplantation. Until then, its application should remain experimental and interpreted with caution. Full article

Structural health monitoring (SHM) is essential for ensuring the safety and longevity of laminated composite structures. Their favorable strength-to-weight ratio renders them ideal for the automotive, marine, and aerospace industries. Among various non-destructive testing (NDT) methods, ultrasonic techniques have emerged as robust tools for detecting and characterizing internal flaws in composites, including delaminations, matrix cracks, and fiber breakages. This review concentrates on recent developments in ultrasonic NDT techniques for the SHM of laminated composite structures, with a special focus on guided wave methods. We delve into the fundamental principles of ultrasonic testing in composites and review cutting-edge techniques such as phased array ultrasonics, laser ultrasonics, and nonlinear ultrasonic methods. The review also discusses emerging trends in data analysis, particularly the integration of machine learning and artificial intelligence for enhanced defect detection and characterization through guided waves. This review outlines the current and anticipated trends in ultrasonic NDT for SHM in composites, aiming to aid researchers and practitioners in developing more effective monitoring strategies for laminated composite structures. Full article

Bone tissue engineering is a technique that simulates the bone tissue microenvironment by utilizing cells, tissue scaffolds, and growth factors. The collagen hydrogel is a three-dimensional network bionic material that has properties and structures comparable to those of the extracellular matrix (ECM), making it an ideal scaffold and drug delivery system for tissue engineering. The clinical applications of this material are restricted due to its low mechanical strength. In this investigation, a collagen-based gel (atelocollagen/glycerol/pullulan [Col/Gly/Pul] gel) that is moldable and injectable with high adhesive qualities was created by employing a straightforward technique that involved the introduction of Gly and Pul. This study aimed to characterize the internal morphology and chemical composition of the Col/Gly/Pul gel, as well as to verify its osteogenic properties through in vivo and in vitro experiments. When compared to a standard pure Col hydrogel, this material is more adaptable to the complexity of the local environment of bone defects and the apposition of irregularly shaped flaws due to its greater mechanical strength, injectability, and moldability. Overall, the Col/Gly/Pul gel is an implant that shows great potential for the treatment of complex bone defects and the enhancement of bone regeneration. Full article

Non-destructive testing (NDT) enables the determination of internal defects and flaws in concrete structures without damaging them, making it a common application in current bridge concrete inspections. However, due to the complexity of the internal structure of this type of concrete, limitations regarding measurement point placement, and the extensive detection area, accurate defect detection cannot be guaranteed. This paper proposes a method that combines the Simultaneous Algebraic Reconstruction Technique with Group Sparsity Regularization (SART-GSR) to achieve tomographic imaging of bridge concrete under sparse measurement conditions. Firstly, a mathematical model is established based on the principles of the tomographic imaging of bridge concrete; secondly, the SART algorithm is used to solve for its velocity values; thirdly, on the basis of the SART results, GSR is applied for optimized solution processing; finally, simulation experiments are conducted to verify the reconstruction effects of the SART-GSR algorithm compared with those of the SART and ART algorithms. The results show that the SART-GSR algorithm reduced the relative error to 1.5% and the root mean square error to 89.76 m/s compared to the SART and ART algorithms. This improvement in accuracy makes it valuable for the tomographic imaging of bridge concrete and provides a reference for defect detection in bridge concrete. Full article

Clinical trials conducted by pharmaceutical companies are essential for bridging local research efforts with broader populations, facilitating the transfer of valuable insights and solutions. This study aimed to explore the barriers and facilitators affecting clinical trials in Saudi Arabia from the perspective of key personnel within the pharmaceutical industry and Contract Research Organizations (CROs). We conducted in-depth semi-structured interviews with nine participants, which provided a holistic understanding of the intricate dynamics shaping the landscape of clinical trials in the country. The analysis revealed three prominent themes: operational challenges, complexities in navigating approval hurdles, and the unique value proposition for conducting clinical trials in Saudi Arabia. The participants expressed pride in the local infrastructure but acknowledged existing flaws, particularly in regulatory processes that contribute to delays in trial initiation. They emphasized the importance of conducting clinical trials in areas such as diabetes, crowd management during pilgrimages, and rare diseases, which are prevalent in the region. Despite the limited number of clinical trials registered (354 from 2009 to 2020, with only 1% being phase 1 studies), Saudi Arabia’s total pharmaceutical market exceeds SAR 13 billion, positioning it as the largest market in the region. Stakeholders recognized the country’s potential as a research hub, particularly within the Gulf Cooperative Council (GCC) region. However, to attract more trials and enhance the medical research landscape, it is crucial to address the identified barriers, streamline processes, and improve stakeholder alignment. The findings highlight the need for targeted interventions to overcome these challenges and leverage Saudi Arabia’s investments in healthcare infrastructure since its transformation program launched in 2010. By enhancing the regulatory environment and fostering collaboration among stakeholders, Saudi Arabia can solidify its role as a key player in international clinical research. Full article

The present study examines the beliefs of pre-service science teachers on creativity in science teaching and learning and identifies factors in the school environment that, in their view, can influence students’ creativity. A total of 152 Colombian prospective science teachers participated in this study. A questionnaire, with an open and a closed part, was administered to participants. Descriptive and inferential statistical analysis of the qualitative and quantitative data collected was carried out. The results revealed that (a) the concept of creativity held by the participants was incomplete and significantly diverged from expert definitions; (b) they viewed creativity as a universal potential that can be nurtured within the school system; (c) the ability to identify problems and ask challenging questions was rarely selected as a creative personality trait; (d) they demonstrated unclear ideas about the relationship between creativity and intelligence and the role of prior knowledge in students’ creativity; and (e) the subject or curricular domain was seen as an important factor influencing students’ creativity. From all this, it could be concluded that Colombian future science teachers exhibited flawed concepts of creativity based on poorly articulated beliefs, which is consistent with findings in other international studies. Full article

The analysis of human perception of vibrations in buildings is a critical aspect of structural engineering, particularly as urbanization intensifies and the proximity of vibration sources to buildings increases. This paper addresses the frequent errors in the assessment and diagnosis of the impact of vibrations on building occupants. Despite stringent standards and detailed methodologies, misinterpretations and incorrect implementations of these guidelines are common, leading to flawed diagnostic studies. These errors often stem from the misuse of measurement equipment, inappropriate selection of measurement points, and a general lack of comprehensive education on vibration analysis. National guidelines, although largely based on ISO standards, vary significantly, contributing to inconsistent practices across Europe. The dominant sources of urban vibrations include vehicle traffic, particularly heavy trucks and rail vehicles, which significantly impact both building structures and human comfort. This paper reviews the methodologies for measuring and interpreting vibrations, emphasizing the importance of correct sensor placement and data analysis. It highlights the necessity of integrating vibrational comfort into building design, considering both external and internal vibration sources. The study also explores the effectiveness of different evaluation methods, such as the RMS and VDV methods, and the impact of various weighting functions on the analysis results. The findings underscore the need for improved education and standardization in the field to ensure accurate assessments and enhance the vibrational comfort of building occupants. Full article

This article delves into optimizing and modeling the input parameters for the selective laser melting (SLM) process on Inconel 625. The primary aim is to investigate the microstructure within the interlayer regions post-process optimization. For this study, 100 layers with a thickness of 40 µm each were produced. Utilizing the design of experiments (DOE) methodology and employing the Response Surface Method (RSM), the SLM process was optimized. Input parameters such as laser power (LP) and hatch distance (HD) were considered, while changes in microhardness and roughness, Ra, were taken as the responses. Sample microstructure and surface alterations were assessed via scanning electron microscopy (SEM) analysis to ascertain how many defects and properties of Inconel 625 can be controlled using DOE. Porosity and lack of fusion, which were due to rapid post-powder melting solidification, prompted detailed analysis of the flaws both on the surfaces of and in terms of the internal aspects of the samples. An understanding of the formation of these imperfections can help refine the process for enhanced integrity and performance of Inconel 625 printed material. Even slight directional changes in the columnar dendrite structures are discernible within the layers. The microstructural characteristics observed in these samples are directly related to the parameters of the SLM process. In this study, the bulk samples achieved a microhardness of 452 HV, with the minimum surface roughness recorded at 9.9 µm. The objective of this research was to use the Response Surface Method (RSM) to optimize the parameters to result in the minimum surface roughness and maximum microhardness of the samples. Full article

It is very important to carry out effective safety inspections on suppression rigging because of the bad service environment of suppression rigging: marine environments. In this paper, the multi-parameter simulation method in ANSYS and ANSYS Electronics Suite simulation software is used to simulate the effect of geomagnetic fields on the magnetic induction intensity of defective pressed rigging under the variable stress in marine environments. The results of the ANSYS simulation and geomagnetic flaw detection equipment are verified. The simulation results show that, according to the multi-parameter simulation results of ANSYS and ANSYS Electronics Suite simulation software, it can be found that, under the action of transverse force, the internal stress of the pressed rigging will affect the magnetic field around pressed rigging with defects. With an increase in internal stress in the range of 0~20 MPa, the magnetic induction intensity increases to 0.55 A/m, and with an increase in internal stress in the range of 20~150 MPa, the magnetic induction intensity decreases to 0.06 A/m. From the use of a force magnetic coupling analysis method, it can be obtained, under the lateral force of the defects in suppressing rigging, that magnetic flux leakage signals decrease with an increase in the rigging’s radial distance. The experiment results show that the difference between the peak and trough of the magnetic induction intensity at the pressed rigging defect calculated by the ANSYS simulation is very consistent with the results measured by the geomagnetic flaw detection equipment. Full article

Additive Manufacturing (AM) of parts used in nuclear power plants can solve many issues like those related to obsolescence. Of the gap limiting the use of AM parts in nuclear is the need of reliable non-destructive inspection capable to meet the qualification requirements. Recently, efforts in this direction have been made worldwide within several research projects, like the EU Horizon 2020 NUCOBAM. In the framework of NUCOBAM, this article presents the activity related to the inspection of 316-L AM nuclear parts produced by L-PBF and inspected via advanced ultrasonic (UT) methods, like MultiPoint Focusing (MPF) and Total Focusing Method (TFM). Multiple UT array probes are used, linear, matrix and annular. Emphasis is dedicated to the inspection of classified valve bodies produced with known internal seeding flaws. The analysis of the results shows the effect of AM induced anisotropy on the propagation of the ultrasonic wave characteristics, the sound velocity increased with 3% when the sound beam deviated 15° against the perpendicular axis. The TFM method contributed significantly regarding defect detection, Signal to Noise Ratios (SNR) increased with at least 9 dB compared to the Multi-Point Focusing method. Smaller errors were noticed when examination frequency was increased and TFM was applied. The combination of an annular array with TFM and mechanical scanning demonstrated to be the best approach. Full article

It has been more than two decades since the Individuals with Disabilities Education Act (IDEA; 1997) included language about the use of functional behavior assessments (FBAs) and behavior intervention plans (BIPs) to address the challenging behaviors of students with disabilities in schools. It has been more than ten years since three technical adequacy studies were published that evaluated school-based FBAs’ and BIPs’ inclusion of essential components and found them to be significantly lacking. The aims of this study were to expand upon the previous research by (a) establishing the psychometric properties of the FBA/BIP Technical Adequacy Evaluation Tool (TATE), (b) evaluating the technical adequacy of 135 completed FBAs and 129 BIPs from 13 school districts across a single state, and (c) comparing the findings to previous studies. The results showed that (a) the TATE has moderate but acceptable internal consistency, excellent inter-rater reliability, and good content validity, (b) the technical adequacy scores of the evaluated products ranged between 40% and 50% of the total components, and (c) most of the BIPs had similar flaws to those seen in the previous research; however, improvement was noted in the FBA components. The implications for practice and suggestions for future research are discussed. Full article