Support Structure Research Articles

Unraveling the ion transport through top and wall coated polyelectrolyte membrane pores

Polyelectrolyte-based nanofiltration membranes are obtained through a layer-by-layer sequential deposition of oppositely charged polyelectrolytes (PEs) onto a porous support structure. The resulting polyelectrolyte membrane offers tailored salt rejections for nanofiltration applications. However, little is known about the exact location of the deposited PEs on top or inside a membrane pore. Also, scarce information is available on the contribution of the different potential PE locations that affect the salt rejection of the overall membrane. Hence, research challenges, such as the influence of (a) an adsorbed PE layer inside the support membrane or (b) the bridging of the original pores and the position of the bridging layer, can only be unraveled through rigorous simulations. We present a significant extension of our previously published model into a two-dimensional modeling framework pEnPEnS (pressure p driven transport through n electrolyte layers En, n polyelectrolyte layers PEn, and the support structure S) capable of addressing the selective layer additionally formed on the walls of the support capillary structure. The model solves a set of two-dimensional nonlinear Extended Nernst-Planck-Poisson and Navier-Stokes-Brinkman equations, enabling the prediction of ionic rejections from the top coating, wall coating, and a PE bridging forming inside the capillary. The proposed model framework systematically identifies and quantifies the influence of the capillary coating beneath the top layer on NaCl rejection and addresses the challenge of improving rejection rates. The model reveals that PEs deposited inside the support structure contribute significantly to NaCl rejection. It enables the predictions of differences in the rejection rates depending on the location of the PE coating, the diameter of the support capillary, and the transmembrane pressure. The model gives insight into PE bridging forming inside the support capillary and explains how its position and fixed charge density change ion rejection rates. As such, the model unravels insightful details on the rejection characteristics of coated capillaries, making it a powerful tool for designing polyelectrolyte membranes.

Modal Analysis and Optimization of Fluid-Structure Coupling for Rotor and Inner Cylinder of Vertical Condensate Pump

Background: Low-frequency resonance is one of the common issues encountered during the variable-frequency operation of condensate water pumps. There have been numerous patents and papers proposing solutions to address the low-frequency resonance problem in condensate water pumps. However, the solutions for resonance problems often need to be tailored to specific circumstances. Methods: Based on the acoustic method, the dynamic model of the rotor and inner cylinder of Jiangsu Guohua Chenjiagang Power Plant 2B condensate pump is established to compare the difference between dry modal and fluid-structure coupling modal, the influence of perpendicularity, concentricity and bearing wear on the natural frequency of rotor is studied. Results: The rotor is rigid under normal conditions. When the bearing is worn, the frequency of the rotor will be greatly reduced and may fall into the frequency conversion operation range to excite resonance. The deviation of perpendicularity and concentricity will not directly lead to the decrease of rotor modal but will lead to the increase of bearing stress, aggravate bearing wear, and then affect the rotor modal. As the inner cylinder only relies on the fixed support at the top, the structure stiffness is low, which may lead to low-frequency resonance. By adding two support structures at the guide vane, the first-order modal frequency of the inner cylinder can be increased from 3.29 Hz to 28.88 Hz, effectively avoiding the operating frequency range of the system. Conclusion: This study can guide the optimization of similar pump structures.

The modified Caldwell-Luc approach for treating odontogenic maxillary sinusitis without need for functional endoscopic sinus surgery (FESS). A retrospective study

BackgroundOdontogenic maxillary sinusitis is a common inflammatory condition resulting from the violation of the Schneiderian membrane by conditions arising from the dentoalveolar unit, which includes teeth, their supporting structures, and adjacent tissues. This study aims to evaluate a modified surgical approach for treating this condition. PurposeThe purpose of this study is to measure the frequency of re-treatment of maxillary sinusitis of odontogenic origin following treatment with a modified Caldwell-Luc approach, which involves accessing the maxillary sinus through the canine fossa without creating a counter-opening in the inferior nasal meatus. Study DesignThis retrospective cohort study included 82 cases (83 sinuses) with odontogenic sinusitis treated surgically with the modified Caldwell-Luc technique at the Department of Oral and Maxillofacial Surgery, Poriya Medical Center, between 2014 and 2021. Patients with non-odontogenic sinusitis were excluded. Predictor VariablesAnatomic findings defined as the presence or absence of ostiomeatal complex abnormalities and oroantral communication, as identified through clinical examination and CT imaging. Main Outcome VariablesThe need for retreatment, defined as the requirement for functional endoscopic sinus surgery (FESS) due to persistent signs and symptoms of maxillary sinusitis after the modified Caldwell-Luc procedure, including facial pain/pressure, nasal congestion, purulent nasal discharge, or radiographic evidence of persistent sinus opacification on CT scan, lasting more than 4 weeks despite appropriate medical management. CovariatesCovariates included demographic data (age, sex [male/female as identified at birth]), smoking status, etiologies of odontogenic sinusitis, and surgical conditions. AnalysesDescriptive statistics, Cox proportional hazards regression was used to compute hazard ratios. Kaplan-Meier survival analysis was performed to estimate the probability of remaining FESS-free over time. The level of statistical significance was set at p < 0.05. ResultsThe sample was composed of 82 patients (83 sinuses) with a mean age of 52.3 years (SD 13.5), and 47 (56.6%) were male. Dental implantation and sinus augmentation procedures were the most common etiologies of odontogenic sinusitis (50.6%). The median follow-up time was 6.03 months (IQR: 2.57 - 10.93 months). The incidence rate of FESS requirement was 2.64 per 100 person-months of follow-up. The FESS-free frequency was 89.2% (95% CI: 80.4% - 94.4%). The Kaplan-Meier analysis estimated the probability of remaining FESS-free at 12 months to be 89.1% (95% CI: 79.8% - 94.4%). Patients with OMC abnormalities had a hazard ratio of 2.25 (95% CI: 0.47-10.84, p = 0.31) for requiring FESS, while those with OAC had a hazard ratio of 1.85 (95% CI: 0.46-7.39, p = 0.38). Conclusions and RelevanceThe modified Caldwell-Luc procedure was effective in treating the majority of odontogenic sinusitis cases. FESS may be necessary in a small percentage of cases with persistent symptoms. Further research is needed to identify predictors for FESS requirement. Of note, we recommend that oral and maxillofacial surgery surgeons review sinusitis cases with a FESS surgeon before performing the modified Caldwell-Luc procedure creating the opportunity for simultaneous or closely timed procedures when necessary

Electrochemical additive manufacturing of interdigitated structures using a multi-anode system with independently-controlled anodes

Interdigitated parts are used across a multitude of engineering applications. The overlapping, intertwined structures pose a challenge for fabrication using conventional additive manufacturing techniques, especially at small size scales. Electrochemical additive manufacturing (ECAM) has been shown to successfully create overhanging parts at the small scale without reliance on support structures. This study extends the ECAM capabilities into demonstration of the fabrication of interdigitated parts by the use of a multi-anode electrochemical additive manufacturing system. The ECAM process is operated by a tool head consisting of multiple anodes independently controlled by individual channels on an in-house-built multipotentiostatic system. Each anode is independently switched into active (anodic) or inactive (open-circuit) mode using a predefined, coded pattern controlling the custom electronics. While each tool is in anodic mode, its current contribution into the overall deposition process is tracked independently as well. Each independent tool can deposit material extending from regions deposited by itself or neighboring tools. The entire multi-head tool is controllably moved by a 3-axis translation system. An interdigitated comb geometry relevant to practical engineering applications is fabricated using this system. This geometry is built using a parallelized voxel-by-voxel tool path with characteristic electrode activation patterns at each position of the tool head. It was found that a purely closed-loop control with no time limit yielded a qualitatively better geometry than a control system with a 10-minute time limit applied. This study overall demonstrates the working principle of a multi-anode system and its ability to fabricate parts interdigitated structures. This study therefore advances the capabilities of ECAM as a valuable additive manufacturing process that can fabricate a variety of challenging parts for relevant engineering applications.

Evaluating Effectiveness and Challenges in B.Ed. Student Teacher Internships

The B.Ed. internship program is essential for teacher preparation, but its effectiveness in preparing future educators for diverse classrooms requires ongoing evaluation. The school internship programme in teacher education is changing from a pre-specified practice-teaching approach to a more comprehensive approach, as emphasized by the NCTE Regulations, 2009 and 2014 respectively. The 2009 regulations expanded the scope of practice-teaching by emphasizing the importance of student-teachers experiencing all school activities and programs. The 2014 regulations further strengthened the component of ‘Field Engagement’ by prescribing a longer duration of 15 weeks. In the present paper researchers has made an attempt to examines the effectiveness and challenges of B.Ed. student teacher internships, focusing on skill development, support structures, and resource availability. It also investigates the program’s impact on student teachers’ confidence in managing diverse classrooms and fostering student success with varying needs and abilities perception of student teachers about the engagement of 15weeks (15+2 weeks) with the field in B.Ed. 3 rd. semester. Internship Programme as per the curriculum of Guru Nanak Dev University Amritsar Punjab. The present study aims to evaluate the effectiveness and challenges faced by student teachers during their internship. The sample consisted of 180 student-teachers selected from B.Ed. colleges of Amritsar district through random sampling. The study, utilizing an open-ended questionnaire, revealed that student-teachers encountered numerous challenges during their internship in the 3rd semester of B.Ed., highlighting the challenges faced by both students and educators.

Build orientation optimization considering thermal distortion in additive manufacturing

Additive manufacturing (AM) technology enables the fabrication of three-dimensional objects with complex shapes and has been extensively applied in various industries. AM is a layer-wise fabrication process where a variety of factors affect manufacturing performance and product quality. One of the most important factor is the thermal distortion, which is caused by the high temperature gradients in the fabrication process. The thermal distortion is also influenced by the support structure of the printing object, and this distortion varies depending on the chosen build orientation. Additionally, for the overhang regions, extra supports are required for printing and will be removed in the post-processing. For the 3D printing process, the thermal distortion and support requirements are interconnected and linked to build orientation. To investigate suitable build orientation, the thermal distortion and support are quantified, and a multi-objective build orientation optimization method is proposed to obtain representative orientations. Based on the proposed method, 9 typical 3D shapes are evaluated. In addition, the single-objective build orientation optimization problem is studied and compared, and the influence of slicing layers per stage on the simulation accuracy and efficiency is discussed. The effectiveness and applicability of the method are verified, and representative directions can be obtained for different fabrication purposes.

Analyzing AI Adoption in European SMEs: A Study of Digital Capabilities, Innovation, and External Environment

This study investigates the effects of digital capabilities, innovation capabilities, and business environmental support on the adoption of Artificial Intelligence (AI) in Small and Medium-sized Enterprises (SMEs). Utilizing dynamic capabilities and resource dependency theories, we provide a comprehensive and integral analysis of the drivers that facilitate AI adoption in SMEs. We conducted an empirical study encompassing 12,108 SMEs, based on survey data of the Flash Eurobarometer database from the European Union. Our analysis employed a combination of classical regression methods and advanced machine learning techniques, including artificial neural networks and tree regression. Our findings highlight the importance of digital capabilities in driving AI adoption, where complementing innovation capabilities exhibit synergistic effects. Contrary to prevailing literature, business environmental support alone demonstrates limited impact, emphasizing its contingent effectiveness within a well-elaborated institutional framework. Furthermore, the synergy between business environmental support and digital and innovation capabilities has a significant impact on AI adoption in SMEs. However, internal capabilities exert a greater influence on AI adoption in SMEs compared to business environmental support. This study contributes to dynamic capabilities theory by elucidating the interplay of digital and innovation capabilities, offering a nuanced understanding of their combined influence on AI adoption. It also enriches resource dependency theory by highlighting the dynamic nature of business environmental support. For practitioners, our results underscore the need for a balanced investment in digital and innovation capabilities. Policymakers should consider these insights when designing support structures for SMEs, emphasizing a comprehensive approach to foster internal capabilities alongside creating an enabling external environment.

Performance of a RuCs/MgO catalyst coated on additive manufactured support structures via electrophoretic deposition for ammonia synthesis

This work investigates the electrophoretic deposition of a catalytic coating on so-called fluid guiding elements (FGE) with a ruthenium-based catalyst for use in ammonia synthesis reactors. FGE are additive manufactured metallic pipe inserts that have shown to enhance the heat transfer compared to empty pipes by dividing the fluid flow and alternately guiding the partial flows to the wall. Consequently, they could improve the performance of temperature sensitive structured catalytic systems. To be able to demonstrate the degree of process intensification, the required steps to enable the deposition of a reference catalyst for ammonia synthesis are developed. Further, the distribution of catalytically active compounds is characterized. The catalytic activity is assessed in a plug flow reactor under pressures up to 5MPa and compared against a fixed bed from the same batch. The expected activity from the reference catalyst is calculated by a kinetic rate expression. The coating process does not affect catalytic activity, but a steady deactivation and high sensitivity to feed gas impurities are observed. Possible mechanisms for the deactivation are examined and discussed.

Towards gradient design of TPMS lattices and laser powder bed fusion processing– Role of laser strategies and lattice thickness

The ability to manufacture complex design geometries via Additive Manufacturing (AM) has led to a rapid growth in advancing the design methods, fabrication, and application of Triply Periodic Minimal Surface (TPMS) lattices with minimal surface topologies. Due to its zero-mean curvature, TPMS lattices can be additively manufactured without any sacrificial support structures and offer both design and manufacturing engineers, unprecedented control over the local physical properties (surface area, relative density, etc.) and local mechanical properties (flexural strength, Young’s modulus, etc.). TPMS lattices are of high interest for a wide range of applications such as biomedical implants, energy absorption, and surface fluidic applications such as heat exchangers, and energy storage. Recent advancements in functionally graded TPMS lattice design by varying local lattice geometry has shown to result in different mechanical performance. However, there have been limited studies in understanding the functional grading of AM process conditions (e.g., Laser-Powder Bed Fusion in this study) and lattice sheet thickness to better map the design-processing conditions-properties. The goal of this study is to achieve similar mechanical properties in TPMS sheet lattices with two different TPMS sheet thicknesses by varying laser processing conditions (e.g., contour and hatch conditions in this study). Quasi-static tensile testing of solid samples with corresponding AM conditions and 3-point bending tests of TPMS lattices were performed in accordance with ASTM E8 and ASTM E290, respectively. It was observed that the flexural properties of the 0.75 mm and 0.25 mm TPMS lattices are similar and exhibit different properties with different scan strategies and speed variations under contour-only and hatch-only laser scanning strategies. Also, the 0.75 mm TPMS sheet lattices exhibited 79 % higher flexural stiffness than the 0.25 mm sheet lattices. It was also observed that this observed trend was reversed in the case of tensile properties. Findings from this study can provide new directions towards achieving gradient TPMS lattice designs with varying local mechanical performance by grading the laser scanning strategies to achieve desired mechanical properties and surface topologies.

Reducing the overpotential of overall water spitting by micro-pump-like electrode engineering

Electrolyzing water for hydrogen generation consumes a significant amount of electricity. Minimizing bubble accumulation on the electrodes can reduce the overpotential, thereby enhancing the efficiency of water electrolysis. In this work, Co1.8Mn1.2S4 as the catalyst for oxygen evolution reaction (OER) was optimized from 54 compounds of oxides and sulfides of Ni, Co, and Mn, then designed a three-dimensional electrode with a pump-like function to expel bubbles from the electrodes. Using laser-assisted curing 3D printing technology, a capillary array with side holes was fabricated and utilized as a support structure for the Co1.8Mn1.2S catalyst. During water electrolysis, the electrolyte enters the interior of the capillary through the side holes, and the bubbles inside the capillary are released from both ends of the capillary. The optimized electrode achieved 10 mA cm−2 at an overpotential of 345 mV during the OER, and reached 100 mA cm−2 at an overpotential of 435 mV. In-situ optical microscopy observations and fluid dynamics simulations demonstrated that bubbles were effectively released through the main outlet of the capillary. In overall water splitting, the current density reached 10 mA cm−2 at 1.646 V, without significant current decay after 60 h continuous operation. The electrode design presented holds promise for broader applications in catalytic reactions, such as CO2 reduction, electrochemical ammonia synthesis, and electrochemical treatment of water pollutants.

Promotion du métier d’agripreneur : clé de la relance du secteur agricole en R.D. Congo

Despite its immense agricultural potential (arable land, rivers, climate, etc.), the Democratic Republic of Congo (DRC) remains a poor country. Unemployment among young people in rural areas, with or without qualifications, is as high as 80%. Yet agriculture could employ over 60% of the population and contribute to the country's food security. This agriculture must be professional, which is where the agripreneur concept comes from. The agripreneur profession can only succeed if technical and financial support structures are put in place. That's what this article is about.

Exact optimization of inter-array dynamic cable networks for Floating Offshore Wind Farms

Optimization of inter-array dynamic cables for Floating Offshore Wind Farms (FOWFs) using three integer linear programs and a heuristic is presented. Design optimization of fixed-bottom offshore wind is a challenging research problem but the presence of dynamic components in FOWFs adds new complexity - as the Floating Offshore Wind Turbine (FOWT), the support structure including the station-keeping system, and the floating power cables all experience dynamic movement in reaction to wind, wave and even current forcing. In this study, dynamic modelling for the response of this system is first carried out to assess the risk of potential mechanical interference between movable elements. Subsequently, safety zones constraints are defined in the optimization to ensure minimally safe conditions for operation of the combined FOWT/support-structure/cables system. Likewise, additional constraints including maximum thermal limits, tree topology without branching, and others are incorporated. The programs follow an incremental approach. Model 1 proposes a simple way to avoid mechanical interference, Model 2 adds variables modelling mooring lines anchoring, and Model 3 increases the degrees of freedom through addition of the positioning of the touchdown point where the dynamic and static sections meet at the seabed. The applicability is illustrated through realistic case studies for a reference FOWF in Europe. Results show that: (i) Modern branch-and-cut solvers are able to solve Model 2 getting the global optimum in seconds, and (ii) further cost refining can be obtained after wrapping Model 3 in the heuristic, using Model 2 as the initial design, decreasing the cost of this layout by around 1.5% in few hours through a nonrectilinear topology.

Manual wheelchair training approaches and intended training outcomes for adults who are new to wheelchair use: A scoping review.

Wheelchair training is pivotal for safety, independence, and occupational engagement in the community, yet adults coming into wheelchair use often receive insufficient or untailored training. This research aimed to understand the range and type of manual wheelchair training approaches that exist for adults commencing wheelchair use. A systematic scoping review involved searching eight electronic databases and grey literature up to September 2023. Papers relating to manual wheelchair training for adults and their caregivers were included for data extraction. Eighty-seven articles were included in this review. The International Classification of Functioning (ICF) was used to organise and analyse data related to intended training outcomes. Consumer consultation was not included in this review; however, the outcomes suggest that involving consumers in future wheelchair training research is critical to assure community participation outcomes. Data were extracted from 87 papers. Manual wheelchair training was delivered across diverse contexts encompassing varied support structures, trainer backgrounds, and technology and was commonly directed towards wheelchair users with spinal cord injury. Intended training outcomes most frequently mapped to the activity and participation component of the ICF (n= 39), followed by personal factors (n= 27), body structures and functions (n= 18), and environmental factors (n= 3), with limited focus on longer term occupational engagement outcomes. Most existing manual wheelchair training focussed on the acquisition of individual wheelchair skill and may not facilitate generalised and long-term occupational participation outcomes. Further exploration into the contexts that support occupational engagement, particularly for older adults with progressive conditions, is required to support service provision. We looked at what manual wheelchair training approaches exist for adults who need to use a manual wheelchair and what training helps people to do/achieve. We did a scoping review that looked at literature about manual wheelchair training programs for adult wheelchair users. We found 87 research papers and training programs that we included in our review. We recorded and analysed information from all the papers about the wheelchair training programs and outcomes for people who do these programs. We found that manual wheelchair training can be done in structured or ad hoc ways, can have different amounts of training, can be provided face-to-face or online, and can be given by different allied health professionals and other wheelchair users. Most training programs had short-term outcomes like learning manual wheelchair skills, being able to use the wheelchair properly, and feeling confident about using a wheelchair. Some had longer term outcomes about being able to use the manual wheelchair in everyday activities. Most people who did the training programs that we looked at in this review were manual wheelchair users with spinal cord injury. Because not many wheelchair programs have been tried with people who do not have a spinal cord injury, it is hard for occupational therapists to make recommendations about training for other people who use a manual wheelchair. Manual wheelchair training that is done in the community and made to meet the needs of individuals may help people with using their wheelchair for their everyday activities and participate in their community.

Effect of some design parameters on the performance of side access nozzle and grooved plate of centre pivot sprinkler

This research evaluates the effect of various heights, pressures, nozzle size and groove numbers on the uniformity distribution of a developed pivot sprinkler. The experiment was set up at an open space in Niger State College of Agriculture Mokwa. The wind speed and temperature during the experiment were at an average of 2.2mph and 25°C. A nozzle of size 6mm, and deflection plate of 6 curved grooves were used in a centre pivot spray unit. In evaluating the performance of the spray unit components i.e. the nozzle and deflection plate, three different pressures of 5, 10, and 15 Psi and heights of 1, 1.2, and 1.5mm were used. The support structure for the experiment is an inverted U-shaped frame designed to support a spray sprinkler at different heights. The water source was a reservoir with a capacity of 3m3and a 1.5hp electric centrifugal pump was used. The volumetric or bucket method was used to measure flow rate. The application rate was measured using catch can method. The duration of each test was approximately 30min. The data obtained from the measurements were statistically analyzed with line graphs using Excel. Relationships were also established between discharge and pressure. The highest index of jet break up was 4.89 at 15Psi and 3.74 at 10Psi. The result shows that as the pressure increases with height the CU also increases. The highest uniformity of 79.4% was obtained at 1.5m height and 15Psi.

Support structure topology optimization considering the residual distortion for laser powder bed fusion metal additive manufacturing

Support structure topology optimization considering the residual distortion for laser powder bed fusion metal additive manufacturing

Study on the effect and mechanism of support structure and characteristic on Ag-based catalysts for low-temperature selective catalytic oxidation of ammonia

Herein, the influence of support type and properties on the catalytic activity and selectivity of Ag-based NH3-SCO catalyst was studied through the evaluation of NH3-SCO performance, the physicochemical characterization of H2-TPR, NH3-TPD, N2 isothermal adsorption–desorption, XPR and XPS, and the mechanism study of 1H MAS NMR, In-situ DRIFTS and DFT calculations. Ag/nano-TiO2, Ag/Al2O3, and Ag/MnO2 all showed better NH3-SCO activity because of more abundant Brønsted and Lewis acid sites of Al2O3 and TiO2 and more actual Ag loading amount due to the larger specific surface area and suitable surface chemistry. The N2 selectivity of Ag/nano-TiO2 is significantly better, which may be due to the highly dispersed Ag species and the abundant Brønsted acid sites with higher N2 selectivity. The mechanism study showed that the terminal hydroxyl was the preferred consumption target of Ag species, and this consumption promoted the effective dispersion and stable anchoring of Ag on the TiO2 surface.

Virtual Learning for Māori Students

This article provides a comprehensive literature review examining virtual learning in the New Zealand schools sector, with a specific focus on understanding and addressing the needs of Māori learners in these online environments. It begins by tracing the historical development of virtual learning in New Zealand from early correspondence courses to the emergence of e-learning clusters and increasing digital technology use. The authors highlight the distinct differences between teaching and learning virtually compared to traditional face-to-face classrooms, exploring unique pedagogical approaches, challenges, and support structures required for effective online instruction and student engagement. Emphasis is placed on the crucial role of fostering strong teacher-student relationships in virtual settings. The article then reviews culturally responsive pedagogies and strategies identified as effective for engaging and supporting Māori learners, and discusses potential frameworks for translating these approaches to online learning environments. The potential of virtual learning to provide more equitable educational opportunities for Māori students, particularly in rural areas, is examined. However, pre-existing socioeconomic inequalities and the digital divide exacerbated by COVID-19 are noted as barriers. Overall, the authors underscore the scarcity of research specifically examining Māori students' experiences and needs in virtual learning contexts. They call for further investigation to better understand and address these gaps, striving to ensure culturally responsive and equitable virtual education opportunities for Māori learners. The paper provides a valuable synthesis of literature and insights into this important issue in New Zealand education.

Stability analysis of deep foundation pit with a double-row cast-in-place piles and diagonal steel lattice braces under sloped excavation conditions

Existing deep foundation pit support structures are commonly composed of external earth-retaining structures, internal horizontal bracings, and vertical columns. A closed bracing system, often formed by a horizontal support through a bracket board, frequently impedes vertical excavation and soil removal operations in the foundation pit, and the processes of assembly and dismantling are complex and time-consuming. This study presents a combined support system and construction method consisting of cast-in-place piles and diagonal steel lattice braces. For sloped excavation, diagonal braces were constructed by slotting through the reserved soil, allowing the use of a single layer of support within the excavation depth. This approach significantly optimizes the construction process, reducing both project duration and overall cost. The field monitoring results indicated that the support method effectively controlled the lateral displacement of the pile bodies. Field monitoring results demonstrated that the proposed support system effectively controlled the lateral displacement of the pile bodies. The adoption of a support-first, excavation-second approach significantly controlled the settlement of the ground surface around the foundation pit, thereby preventing excessive increments in the axial force of the supports due to the large longitudinal depth excavation. The calculation results of the three-dimensional finite element model for foundation pit excavation and support indicate that the proposed support method results in a decreasing ratio of the maximum lateral deformation depth of the pile body, denoted as δh-m, to the excavation depth He as the excavation depth increases. This implied that the displacement of the pile body was strictly controlled. When the depth of the foundation pit excavation exceeded 10 m, the maximum lateral deformation occurred below 10 m along the pile shaft. The diagonal steel lattice braces transferred the load to the top of the cast-in-place piles at the bottom of the pit, where the stress concentration occurred. During construction, special attention must be paid to the strength of the connection between the pile top and the connecting beams.

An extreme thermal cycling reliability test of ATLAS ITk Strips barrel modules

At the end of Run 3 of the Large Hadron Collider (LHC), the accelerator complex will be upgraded to the High-Luminosity LHC (HL-LHC) in order to increase the total amount of data provided to its experiments. To cope with the increased rates of data, radiation, and pileup, the ATLAS detector will undergo a substantial upgrade, including a replacement of the Inner Detector with a future Inner Tracker, called the ITk. The ITk will be composed of pixel and strip sub-detectors, where the strips portion will be composed of 17,888 silicon strip detector modules. During the HL-LHC running period, the ITk will be cooled and warmed a number of times from about -35°C to room temperature as part of the operational cycle, including warm-ups during yearly shutdowns. To ensure ITk Strips modules are functional after these expected temperature changes, and to ensure modules are mechanically robust, each module must undergo ten thermal cycles and pass a set of electrical and mechanical criteria before it is placed on a local support structure. This paper describes the thermal cycling Quality Control (QC) procedure, and results from the barrel pre-production phase (about 5% of the production volume). Additionally, in order to assess the headroom of the nominal QC procedure of 10 cycles and to ensure modules don't begin failing soon after, four representative ITk Strips barrel modules were thermally cycled 100 times — this study is also described.

Analysis of the load‐bearing characteristics of hydraulic supports for top‐coal caving under the impact of coal and gangue

AbstractTo study the effect of different sizes and speeds of coal gangue falling on hydraulic supports for top‐coal caving discharge hydraulic support on the bearing characteristics of the hydraulic support, the ADAMS hydraulic support rigid‐flexible coupling analysis model was established. HyperMesh is used to flexibly process the hydraulic support, and the column and jack are equivalently replaced by spring damping system. By applying step loads of different sizes and speeds to simulate the impact force generated when the coal gangue falls on different positions of the cover beam, the dynamic response characteristics of the column, balance jack and other articulation points are obtained. Analyses show that: when the impact load is closer to the roof beam, the articulation point of the roof beam‐cover beam and the balancing jack are easy to be damaged. When the same impact load is applied to the cover beam, the faster the load is applied, the hydraulic support column and balancing jack may not be able to absorb and disperse the pressure effectively in time, resulting in the articulation points being subjected to a larger impact force, which is easy to cause damage or destruction. When different sizes and speeds of impact loads are applied to the cover beam, the latter has a greater impact on the dynamic response of the front and rear connecting rod articulation points and the cover beam‐roof beam articulation point than the former, and the hydraulic bracket will be more prone to vibration, deformation, and stress concentration, thus affecting the stability and safety of the bracket. The article is of guiding significance for designing and optimizing the structure and parameters of the hydraulic support, and improving the support performance and stability of the hydraulic support in the comprehensive release working face.