Strength Capacity Research Articles

Lithocholic acid phenocopies anti-ageing effects of calorie restriction.

Calorie restriction (CR) is a dietary intervention used to promote health and longevity1,2. CR causes various metabolic changes in both the production and thecirculation of metabolites1; however, it remains unclear which altered metabolites account for the physiological benefits of CR. Here we use metabolomics to analyse metabolites that exhibit changes in abundance during CR and perform subsequent functional validation. We show that lithocholic acid (LCA) is one of the metabolites that alone can recapitulate the effects of CR in mice. These effects include activation of AMP-activated protein kinase (AMPK), enhancement of muscle regeneration and rejuvenation of grip strength and running capacity. LCA also activates AMPK and induces life-extending and health-extending effects in Caenorhabditis elegans and Drosophila melanogaster. As C. elegans and D. melanogaster are not able to synthesize LCA, these results indicate that these animals are able to transmit the signalling effects of LCA once administered. Knockout of AMPK abrogates LCA-induced phenotypes in all the three animal models. Together, we identify that administration of the CR-mediated upregulated metabolite LCA alone can confer anti-ageing benefits to metazoans in an AMPK-dependent manner.

Cyclic Performance of Prefabricated Bridge Piers with Concrete-Filled Steel Tubes and Improved Bracing Connection Detail

Concrete-filled steel tubes (CFTs) offer significant structural advantages in terms of stiffness, strength, and ductility. The concrete core enhances the stiffness and compressive strength of columns, whereas the steel tube serves as a reinforcement to resist tension and bending by confining the concrete. Moreover, CFT columns offer exceptional resistance, such as high strength, ductility, and energy absorption capacity. This study presents experiments focused on prefabricated bridge piers featuring multiple CFT columns. Commercial circular steel tubes were utilized to streamline fabrication efforts, with bracings employed to enhance structural performance by connecting the CFT columns. Component tests were conducted for different connection details to prevent premature failure owing to cyclic loading. A full-scale modular pier was designed to explore its cyclic behavior using the bracing connection details derived from the component test. The plastification location in a modular pier can be designed using the connection details, as validated experimentally. The results of this study indicate that CFT columns, as the main component of the bridge pier, can be protected by designing connection details to induce stress concentration in the braces, thereby achieving ductile behavior.

Length effects of PE-based selvage fibers on fresh, fiber dispersion, and tensile properties of engineered cementitious composites

Due to high cost and embodied energy of synthetic fibers, their use in engineered cementitious composites (ECCs) is a barrier against the practical applications of ECC. This study investigated the length effects of fibers obtained from polyethylene-based selvage, the edges of woven fabrics that are normally discarded, on fresh, fiber dispersion, and tensile properties of ECC. Three ECC mixtures were designed with selvage fibers with lengths of 5, 10, and 15 mm. Mini-slump and mechanical tests were performed, and fiber dispersion was evaluated. Test results showed that flowability increased as the length of selvage fibers decreased. On the other hand, compressive strength, tensile strength, and tensile strain capacity increased as the length of selvage fibers increased. It was observed that the length of selvage fibers had little influence on fiber dispersion. The tensile properties of F-5 mixture, showing minimum performance, were superior to those of recycled fiber-reinforced ECCs.

Strength Proxies Explain Balance Task Performance by Proximity to Peak Height Velocity in Young Acrobatic Gymnasts

Background: Balance tasks are critical for performance in acrobatic gymnastics, where athletes often train and compete in mixed-age groups with varying maturational stages. To improve individualized training, in this cross-sectional study, the relationship was examined between strength capacity and balance task performance in female gymnasts at two maturational stages based on peak height velocity (PHV). Methods: Circa-PHV (n = 17, 11.92 ± 1.7 years) and post-PHV (n = 17, 16.47 ± 1.8 years) participants performed static balance tasks (standing on blocks, tandem stance, headstand) while center of pressure (CoP) excursion was recorded, and a proactive balance task (time to stabilization after landing, TTS). Strength assessments included isometric mid-thigh pull, handgrip, countermovement jump (CMJ), and push-up tests. Results: Correlational, regression, and inter-group analyses highlighted differences in strength–balance relationships across groups. Maximal isometric strength and CMJ power were the strongest predictors of static standing balance, with greater predictive strength in the circa-PHV group, underscoring the role of maturation in strength–balance interactions. The results also revealed that strength parameters influenced balance differently depending on the task, suggesting that specific balance types (static–proactive) and tasks (standing–inverted) require distinct strength capacities. Conclusions: Strength’s influence on balance varies by maturational stage, emphasizing the need for tailored training programs to enhance balance and optimize performance in young gymnasts.

Do Patients with Rheumatoid Arthritis Have an (In)Adequate Level of Physical Activity? A Latent Class Analysis Approach

Introduction: Regular physical activity (PA) has a beneficial effect on joint pain, stiffness, strength, flexibility, and aerobic capacity in patients with rheumatoid arthritis (RA). Objective: The aim of this study was to assess the level of PA in patients with rheumatoid arthritis and to identify potential barriers to this activity. Material and Methods: The study involved 132 patients with RA. Participants completed the International Physical Activity Questionnaire (IPAQ), the Functional Assessment of Chronic Illness Therapy—Fatigue Scale (FACIT-F), the Tampa Scale for kinesiophobia (TSK), Strength, Ambulation, Rising from a chair, Stair climbing and history of Falling questionnaire (SARC-F) for sarcopenia assessment, and the Patient Health Questionnaire-9 (PHQ-9) for depression. Basic socio-epidemiological data, disease activity score in 28 joints (DAS28), duration of disease, and therapy information were retrieved from electronic patient records. Latent class analysis (LCA) was used to identify subpopulations of patients. Results: The study included 109 women (82.6%) and 23 men (17.4%). Low levels of PA were observed in 16 patients (12%), moderate levels in 70 patients (53%), and high levels in 42 patients (35%). Symptoms of pronounced fatigue were significantly associated with low PA (28.5 ± 11.3 vs. 37 ± 7 vs. 37 ± 10; p = 0.002). The risk of sarcopenia was significantly higher in RA patients with low PA (p = 0.05). Kinesiophobia was present in all three groups (65.2%). LCA identified two classes. In the first class, patients were more likely to be non-exercisers compared to the second class. Patients in the first class were characterized by a higher probability of being female, obese, with lower education levels. Patients in the first class had pronounced fatigue, kinesiophobia and more frequent symptoms of depression. The second class (65% of the total population) included patients who exercised moderately to frequently (93%) and were middle-aged. They were less obese, highly educated, employed, and majority of them achieved low disease activity or remission. In addition, they had lower risks for sarcopenia, depression, fatigue, and kinesiophobia. Conclusions: This study showed that RA patients with moderate and high levels of PA have better disease control, fewer symptoms of fatigue and depression, and a lower risk of sarcopenia. However, kinesiophobia was significantly present in all three groups, indicating a need for further promotion of this non-pharmacological treatment.

Feasibility and preliminary efficacy of a skill-based lifestyle intervention for enhancing cooking abilities and physical fitness in young adults with intellectual disabilities.

Individuals with intellectual disabilities (ID) often experience poorer diet quality and lower physical fitness levels as they transition from adolescence to adulthood. The purpose of this study was to assess the initial feasibility and efficacy of Chef-ID, a 12-week intervention designed to improve cooking skills and physical function in young adults with ID. Young adults with ID attended weekly group sessions which provided hands-on cooking skills, nutrition education, and exercise. Participants were also asked to attend monthly, virtual, goal setting sessions. Feasibility outcomes included attendance, retention, and safety. Preliminary efficacy outcomes included cooking skills, lower body muscle strength, grip strength, aerobic capacity, and body weight. Paired t-tests were used to assess the differences in cooking skills, strength measures, aerobic capacity, and weight after the 12-week intervention. Study retention was 95%, attendance exceeded 85% for all sessions, and no serious adverse events were reported. The number of cooking skills participants could do independently (p=0.005), the number of cooking skills requiring only a verbal prompt (p=0.01) and lower body strength (p=0.004) significantly improved across the 12-week intervention. The number of cooking skills participants had no exposure to (p=0.01) and weight (p=0.036) significantly decreased across the intervention. No significant changes were observed for upper body strength or aerobic capacity. The Chef-ID intervention was feasible with desirable initial effects on cooking skill independence, exposure to cooking skills, lower body strength, and weight. The Chef-ID intervention holds promise in enhancing cooking skills and physical function among young adults with ID. Clinicaltrials.gov, NCT05385016.

Shear Strengthening of RC Beams Using Partial-Length Near-Surface Mounted (PLNSM) CFRP Strips

Shear strengthening of reinforced concrete beams using near-surface mounting (NSM) method with fiber-reinforced polymer (FRP) strips is more effective because of improved bond strength, better fire resistance and high maintainability. However, the surface preparation for NSM method is a difficult process where the beam–slab corner is not accessible by the rotary blade of the groove-making equipment. Consequently, the application of NSM method becomes more difficult to apply. Therefore, in this study, the effect of reducing in NSM length on the shear strength has been investigated by reinforcing only a part of the height, not the entire web of beam, referred to as the partial-length NSM method (PLNSM). Half scaled five RC T-beams were made and tested under symmetrical four-point static loading system. All except one was strengthened in shear in which the effect of reduced NSM length was balanced by inclining the partial-length NSM strips (IPLNSM). Furthermore, to mitigate the detrimental effect of reduced lengths of NSM strips, the retrofitting was enhanced by additional externally bonded reinforcement (EBR) method using CFRP sheets. The results showed that there was no significant negative effect of reduced NSM length on the strength of the strengthened specimens, and by providing inclined NSM strips, significant improvement in the strength was observed. Additionally, the hybrid approach combining the inclined partial length NSM (IPLNSM) and EBR method showed improvement in strength and deflection capacity. Lastly, when compared with the currently available design procedures, it was found that the available formulation can predict the design strength of PLNSM and IPLNSM reinforcement, thus making them a viable option for retrofitting reinforced concrete beams.

Multi-parameter coupling modeling method and hybrid mechanism of concrete-encased CFST hybrid structures

Concrete-encased concrete-filled steel tubular (CFST) hybrid structures consist of encased CFST components and reinforced concrete (RC) encasement, posing unique challenges related to their hybrid mechanisms and coupling effects. This study addresses these issues by proposing an automatic and efficient Finite Element (FE) modeling method, which accounts for multiple constitutive models of confined concrete, meticulous grid division and reasonable interaction. The FE modeling method was packaged with a user-friendly graphical interface in the software ‘Auto CECFST’, which has been shared on GitHub(https://github.com/CECFST/Auto-CECFST.git). The modeling method has been verified by test results on the strength, stiffness and deformation capacity. Utilizing the refined FE modeling method, 7776 FE models are generated based on an orthogonal combination of 7 critical parameters of concrete-encased CFST hybrid structures. To accurately define failure modes, stress ratio (φ) was proposed to achieve quantitative analysis on the failure mode, followed by a comprehensive investigation into the full-range analysis of the hybrid mechanism of two components. Moreover, further exploration focused on multi-parameter coupling effects of critical mechanism characteristics, including strength, stiffness, and deformation capacity, elucidating the hybrid mechanism and mechanical similarities between single and multi-chord structures. Based on the above analysis, the balance of strength and deformation ability could be achieved by certain parameter ranges. Finally, available strength and stiffness calculation methods are validated against experimental and FE results under three typical failure modes, revealing the advantages and limitations of calculation methods on the basis of mechanics and data statistics, which provides a basis for security structural design.

An Experimental Study on Industrial Concete Pile Foundation in Soft Soil: Comparison of Monolithic and Pile with Welded Joints

This study presents an experimental investigation into the industrial foundation piles. The research carried out employed both destructive and non-destructive testing methods to evaluate the concrete compressive strength and flexural strength capacity of the piles under monotonic loading. The Destructive Test (DT) involves a 28-day cylinder concrete compressive test, while the Non-Destructive Test (NDT) utilizes the Ultrasonic Pulse Velocity (UPV) and Rebound Hammer (RH) tests. The flexural strength test is conducted using a loading frame, and the results are compared to the GeoPIV-RG, which measures the displacement during the test. The experimental investigations provide insights into the behavior of pile joints when subjected to monotonic load in soft and loose soil. The results indicate a significant difference between the compressive strength obtained from the DT and NDT, with a ratio of 0.64-0.74. Furthermore, the failure occurred at the joints, rather than the welded area, with the ratio of the initial stiffness of the piles with joints to the monolithic pile being 0.15 for zig-zag welded and 0.30 for circular welded, and reaching an average value of 0.225. According to the GeoPIV-RG result, the displacement is similar to the flexural strength test result.

Isostatic and frictional energy dissipating connecting systems for UHPC curtain walls: Design and experimental validation

Ultra-high performance concrete (UHPC) curtain wall is a new type of non-structural building envelope component. Given its large size and high cost, rational connecting systems should be employed to prevent potential seismic damage and economic losses. In this study, two novel connecting systems, including an isostatic connecting system and a frictional energy dissipating connecting system, were proposed for reinforced concrete (RC) frame with UHPC curtain walls. The design methods for these two connecting system were provided first. Then, to evaluate the feasibility of the proposed connecting systems and the corresponding design methods, three 1/2-scale RC frame structures (i.e., one bare frame without curtain walls, one with isostatic curtain wall connecting system, and one with frictional energy dissipating curtain wall connecting system) were designed and fabricated for pseudo-static tests. The damage evolution, failure mode, strength, stiffness, and energy dissipation capacity of the three test substructures were assessed. The test results demonstrated that through reasonable design, independent rocking deformation of the curtain walls was achieved in both the isostatic and frictional energy dissipating connecting systems, allowing the curtain walls to remain free from damage even under an inter-story drift of 1/36, thus validating the reliability of the proposed connecting systems and design methods. Further, compared to the bare frame, curtain walls employing the isostatic connecting system exhibited a negligible effect on the seismic performance of the frame. On the contrary, curtain walls employing frictional energy dissipating connecting system effectively enhanced the strength and energy dissipation capacity of the frame, allowing dual damage control for both walls and frame. Consequently, the frictional energy dissipating connecting system is considered to be a more rational method for enhancing the seismic performance of buildings.

Effects of Na2SiO3/NaOH ratio in alkali activator on the microstructure, strength and chloride ingress in fly ash and GGBS based alkali activated concrete

In this study, the impact of alkaline solutions composed of various Na2SiO3/NaOH ratio and NaOH molarity on the strength, chloride ingress and chloride binding capacity of fly ash (FA) and ground granulated blast furnace slag (GGBS) based alkali activated concrete (AAC) was investigated. The microstructural properties of alkali activated binders (AAB) composites was also studied to understand its influence on the chloride permeability of AAC. Chloride permeability of concrete was tested by using the rapid chloride penetration test (RCPT) and by immersing concrete in NaCl solution (ASTM C1556). The compressive strength, chloride ingress and chloride binding capacity of AAC was compared with Portland cement-based concrete (OPC). Results showed that higher Na2O/SiO2 ratio in alkaline solutions resulted in a weak microstructure with, low strength and high chloride ingress. Concrete activated by alkaline solutions with Na2O/SiO2 molar ratio =1 (+3), exhibited greater compressive strength and resistance to chloride ion penetration. The increase of SiO2 concentration in alkaline solution greatly reduces the binding capacity of AAC while the bound chlorides increased with the NaOH molarity. No chemical chloride binding was observed in AAC but for OPC concrete, calcium salts formed in the microstructure after immersion in NaCl solution. Compared to OPC concrete, AAC showed superior performance in terms of strength and chloride diffusion making it a potential candidate for application in marine structures.

Pericapsular nerve group (PENG) block versus supra-inguinal fascia iliaca (SIFI) block for functional outcome in patients undergoing hip surgeries – A randomised controlled study

Background and Aims: In hip surgeries, the pericapsular nerve group (PENG) block and supra-inguinal fascia iliaca (SIFI) block are commonly employed perioperative regional analgesia techniques. This study aimed to compare functional outcomes regarding quadriceps muscle strength and weight-bearing capacity between PENG and SIFI blocks after hip surgery. Methods: In this single-centre, double-blinded, randomised trial, 60 patients undergoing hip surgeries under subarachnoid block were randomised into either Group P (PENG block) or Group S (SIFI block). Blocks were administered under ultrasound guidance with 30 mL of 0.2% ropivacaine and 4 mg dexamethasone. Functional mobility was assessed 24 and 48 h postoperatively by measuring quadriceps strength and maximum weight-bearing capacity. Analgesic efficacy was also evaluated by comparing visual analogue score (VAS) scores at 24 h, total opioid consumption over 24 h, and duration of analgesia. Statistical analysis included Student’s t-test, Chi-square, and Z-test as appropriate, with statistical significance set at P < 0.05. Results: Group P demonstrated significantly higher quadriceps-muscle strength at 24 h (P = 0.025) and 48 h (P = 0.002) post surgery. More patients in Group P achieved superior weight-bearing grades at 24 h (P = 0.002) post surgery compared to Group S. VAS scores were significantly lower in Group P at 24 h post surgery (P = 0.006). Group P also showed a prolonged duration of analgesia (P = 0.019) and lower mean opioid consumption (P = 0.001) compared to Group S. Conclusion: The PENG block may be superior to the SIFI block in terms of functional outcomes with better quadriceps strength, enhanced weight-bearing, and provision of more effective postoperative analgesia in hip surgery patients.

Natural materials modified mud mortar for rubble stone masonry: An experimental and numerical study

Rubble stone masonry is a long-standing construction. However, its binding material and mud mortar exhibit shortcomings, including low tensile and shear strength and poor water resistance. To overcome these limitations, researchers have initiated investigations into modifying mud mortar, specifically focusing on the influence of natural materials on their performance. This study used straw (0-1wt%) and starch (0-7wt%) as modifiers for mud mortar. The modified mortar underwent compression, straight shear, split tensile, water immersion, and abrasion tests to investigate its mechanical properties and water resistance. Additionally, electron microscope scanning was employed to reveal the modification mechanism of mud mortar at the microstructural level. The study results showed that 0.5wt% straw/ 5wt% starch was the optimal blended mortar. In contrast, for compressive strength, tensile strength, cohesion, and water absorption capacity, starch was better than straw, and for internal friction angle and abrasion resistance, straw was better than starch. The modification mechanisms of both were bridging and gelling effects, respectively. Lastly, finite element numerical simulations were employed in this study to analyze how modified mud mortar influences the shear performance of rubble stone masonry walls. The results demonstrated that adding both straw and starch substantially enhanced the shear strength and ductility of the walls. Specifically, the additions of 0.5wt% straw and 5wt% starch increased the shear strength by 18.12% and 9.1% and the ductility by 8.48% and 0.83%, respectively. This study significantly advances low-carbon, green buildings, and sustainable development.

Ultrasonic treatment of emulsion gels with different soy protein-hemp protein composite ratios: Changes in structural and physicochemical properties

To improve the emulsion gel system of single soybean isolate protein (SPI) and to broaden the application field of hemp protein isolate (HPI), ultrasonic treatment and HPI were introduced to improve the properties of SPI emulsion gel and to explore the mechanism. The results showed that the gel strength (218.6 g) and water-holding capacity (86.24 %) of the emulsion gels were improved under ultrasonic treatments when the ratio of SPI:HPI was >6:4, and the reticulation structure of the gels was enhanced. When the ratio of SPI:HPI was <6:4, the gel structure was loose and formless. Ultrasonic treatment has a significant effect on the emulsion gel with the ratio of SPI:HPI was >6:4. Appropriate ultrasonic treatment (400 W) changed the protein structure, improved the rheological properties of emulsion gels to form the protein-oil-coated network structure. However, excessive ultrasonic treatment (600 W) will destroy the conformation of the protein, reducing the stability of the structure. The effect of ultrasonic treatment on emulsion gels with the ratio of SPI:HPI was <6:4 is low, but improved the gel protein digestibility. This study provides a theoretical basis for the application of ultrasonic in composite protein emulsion gels systems and the development and application of HPI.

The impact of concurrent training in team sports and soccer.

Team sports players are frequently required to integrate multiple physical components, including strength and endurance capacity, to maximize their performance during both training and competitions. The combination of strength and endurance within a periodized program is known as concurrent training. Recently, concurrent training has emerged as an innovative method to enhance both muscular strength and aerobic performance, tailored to the specific requirements and diverse nature of each sport. However, concurrent training may induce excessive fatigue and compromise performance potentiation, depending on training prescription parameters. This distinction between the interference effect and performance enhancement presents a complex challenge for any team sports system. Consequently, the objective of this review was to scrutinize the efficacy, practical application, and methodological aspects of concurrent training. Additionally, it aims to elucidate strategies to mitigate the complexities associated with the interference effect, thereby optimizing the benefits of concurrent training modality for team sports, emphasizing soccer. The major findings indicate that concurrent training can improve strength and endurance qualities in athletes, but under certain conditions, it can also interfere with adaptations. Appropriate programming strategies, such as proper sequencing, scheduling, volume, intensity, and recovery, can help mitigate these negative effects. Additionally, whereas more experienced athletes display greater proficiency in executing concurrent training programs, younger players, particularly those under 14, tend to experience minimal interference effects from this training approach, making it well-suited for their development. Overall, concurrent training has been demonstrated as an effective and efficient method for improving strength and endurance performance in team sports players.

Experimental and Numerical Investigation of Steel Panel Links with Different Trapezoidal Corrugations

A novel type of steel panel link with a trapezoidal corrugated section is developed, which is called the corrugated steel panel (CSP) link, aiming to improve both the strength and energy dissipation capacity of the steel links. Quasi-static tests were carried out on two specimens with different corrugation inclination angles to investigate their seismic performance. Test results indicated that Specimen CSP-V (corrugation inclination angle of 90°) and Specimen CSP-H (corrugation inclination angle of 0°) exhibited distinct failure modes due to the differing out-of-plane constraints provided by their corrugations. Numerical analysis was conducted using the general finite element program, ABAQUS, to supplement the test results. Analytical findings suggested that CSPs with a 90° corrugation inclination angle could provide superior ductility, both yield and peak strengths demonstrated a strong linear correlation with the aspect ratio (H/L ratio). For CSPs with a 0° inclination angle, superior strength and stiffness were observed, the relationship between lateral strength and the H/L ratio was better described by a power-law correlation. Furthermore, to achieve comparable seismic performance, the H/L ratio of CSPs with a 0° inclination angle should be at least twice that of CSPs with a 90° inclination angle.

Use of Wheat Fiber and Nanobentonite to Stabilize Clay Subgrades

Since clayey soils naturally present low mechanical strength, they pose direct challenges for engineering applications. Finding appropriate soil stabilizers to address the challenges posed by clayey soils is crucial for ensuring that the soil meets the necessary geotechnical requirements and fulfills economic and environmental issues. To this end, this research uses several stabilizers and techniques in clayey soils to improve their suitability for construction. The main objective of this study is to assess the use of wheat fiber and nanobentonite (NB) in soil stabilization, estimate their behavior in practices, outline their obstacles and potential for soil improvement, and consider their ecological and financial effects. This research also evaluates the behavior of the soil by incorporating NB (0.4, 0.8, and 1.2%) as a stabilizing agent. For this purpose, the randomly dispersed wheat fibers as a reinforcing agent at different dosages and lengths (0.3, 0.6, 0.9%, and 5, 10, and 15 mm) were combined to the soil matrix. The soil was characterized by conducting compaction, unconfined compressive strength (UCS), direct shear (DS), California bearing ratio (CBR), indirect tensile strength (ITS), freezing-thawing (F-T) tests, and microstructural analysis. The data were used to assess the effect of wheat fiber and NB on the soil’s geotechnical properties. The results revealed that incorporating 0.8% NB into the soil led to the best enhancement in compressive strength. This improvement is attributed to the dehydration and formation of a viscous-like film between the soil particles. In addition, 0.6% fibers with a length of 15mm increased the interaction and bonding forces between the particles of soil, resulting in a maximum increase in compressive strength. Combining fibers and NB improved the shear strength, tensile strength, and bearing capacity. Besides, the stabilized soil exhibited superior resistance to freezing-thawing cycles compared to the unreinforced clay. Overall, the results indicate that using wheat fibers and NB is a cost-effective and eco-friendly solution for stabilizing clay subgrades.

Economic and Sustainable UHPC at Scale: Material Variability Study and Application to Full Axial Columns

The high cost of robust UHPC of a proprietary nature and expensive constituents hinders mass production and expansion into full structural applications. This study provides experimental research and validation to support new initiatives in scalable, economical UHPC of a semi-proprietary nature that leverages local and sustainable materials and explores the use of raw recycled tire fibers. The study provides comprehensive material trials and mechanical characterization validated through the fabrication and testing of five full-scale axial UHPC columns with varying reinforcement ratios, fiber ratios, and types of fibers. Overall, the result shows that incorporating local and sustainable components into proprietary mixtures does not compromise the mechanical properties of UHPC with compressive strength of more than 150 MPa and modulus of elasticity ranging from 41.8-43.4 GPa. In addition, the axial strength capacity of economical UHPC columns, designed accordingly with ACI, performed better than non-ACI-compliant columns by up to 26.8%.

Developing Innovative Nano-Engineered Lightweight Foamed Concrete Incorporating Iron Oxide (II, III) with Enhanced Mechanical and Transport Properties

Recently, scientists have focused substantial attention on the incorporation of nanoscale components in cement-based materials. Iron oxide (II, III) nanoparticles (IONPs) have garnered significant attention in nanoparticle research. This paper portrays preliminary discoveries of an investigation assessing the characteristics of foamed concrete (FC) with the presence of IONPs. A comprehensive assessment of characteristics was conducted, including its workability, axial compressive strength, bending strength, tensile strength, apparent porosity and water absorption capacity. Furthermore, scanning electron microscope examination was performed and evaluated. The results indicate a significant enhancement in the FC strength characteristics, with 28-day compressive, tensile, and bending strengths improving by up to 70, 76 and 52 %, respectively, with the inclusion of 3 % IONPs. Nonetheless, adding IONPs beyond 3 % did not yield significant improvements in mechanical properties. With a rise in IONPs from 1 to 5 %, the FC exhibited significant improvements in apparent porosity and water absorption. The decreasing pore size in FC containing IONPs was found to be the cause of the anomalies. A significant alteration in the arrangement of pore dimensions was noted in FC mixtures when the amounts of IONPs were modified. Results from this investigation emphasise the prospective benefits associated with integrating IONPs into FC, that could boost its entire characteristics.

Construction of lightweight, high-energy absorption 3D-printed scaffold for electromagnetic interference shielding with low reflection

The pursuit of advanced electromagnetic interference (EMI) shielding materials, featuring lightweight, programmable structures, low reflection, and essential mechanical properties, presents both promise and challenge. In this study, a scaffold based on triply periodic minimal surface (TPMS) with 70 % porosity was designed using 3D printing technology, showcasing enhanced compressive strength and impressive energy absorption capacity. Building upon this scaffold, the monolithic layered dipping method served as an innovative strategy to easily regulate gradient distribution of carbon nanotube (CNT) on 3D-printed scaffold and ensured their integrity. Moreover, the gradient conductive 3D-printed scaffold, with a rational CNT distribution, features a dramatically reduced reflection power coefficient of 0.13, achieving an EMI shielding effectiveness (SE) up to 35.9 dB, indicating that 99.99 % of EM waves are blocked upon penetration. Finite element analysis (FEA) justifies that the 3D-printed scaffold with increased gradient CNT content was more effective in absorbing EM waves, highlighting its remarkable design flexibility and practical feasibility of gradient conductive structure. Furthermore, we analyze the EM waves attenuation mechanism of gradient conductive 3D-printed scaffold, facilitated by introduces multiple loss mechanisms, which effectively establishing an "absorption-reflection-reabsorption" process for dissipating EM waves. This work is expected to open new avenues in the field of FDM 3D printing technology in the fabrication of low reflection EMI composites.