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Strength is a central element of sport and therefore an equally central topic in sports science. In sports science, strength is dealt with primarily in biomechanics. Biomechanics reduces strength – legitimately – to a scientific subject. As a result, it loses sight of strength as a lifeworld phenomenon. The discipline that allows us to grasp strength as an everyday experience is phenomenology. This essay undertakes a phenomenological analysis of strength to uncover the diversity of strength phenomena in the lifeworld of sport. The theoretical and methodological basis for this is Hermann Schmitz's 'new phenomenology' (Neue Phänomenologie). With the help of new phenomenology, I first develop a real definition of strength ('strength is an intrusive effect through one-sided incorporation'). Second, I work out the general structures of the phenomenon of 'strength', that is, a system comprising ten categories ('pulling, pushing, centripetal, centrifugal, lifting, lowering, strong, weak, heavy, light'). Third, I use this system of categories for a phenomenology of sport-immanent strength phenomena. The paper thus makes a contribution to a pure phenomenology of sport. [ABSTRACT FROM AUTHOR]

Background: Detraining is the partial or complete loss of physical training-induced adaptations as a result of exercise interruption or reduction. The COVID-19 pandemic led to the discontinuation of many older adult exercise programs and led to increased depressive symptoms (DS), increased sedentary behavior (SB), and decreased quality of life (QoL). Objective: To evaluate the effects of detraining, in the pandemic, on physical capacity and its relationship with DS, QoL, and SB of community-dwelling older adults. Methods: The physical capacity (static balance, dynamic balance, and lower limb and handgrip strength) of 35 participants was assessed prepandemic and after 18 and 24 months of the pandemic. DS, QoL, and SB were evaluated only at 18-month period. The analysis of variance for repeated measures or the Friedman and Pearson or Spearman tests were used for statistical analysis. Results: There was a decline in dynamic balance (p <.001) and strength in the lower limbs (p <.001) in the first 18 months, as well as maintenance in the following 6 months. The reduction in dynamic balance during the 18 months of the pandemic was associated with greater DS (p =.015; r =.414) and worse QoL (p =.024; r = −.381) in this period. More time spent on SB (p =.024; r =.386) in the 18th month was associated with worse dynamic balance in the following 6 months. Conclusion: Detraining in the pandemic setting led to long-lasting harmful effects, which can last for 2 years, on the physical capacity of community-dwelling older adults. Implication: Our findings highlight how periods of detraining can interfere in physical and mental health of older adults. [ABSTRACT FROM AUTHOR]

Purpose: Agility in young soccer players has long been associated with physical attributes like strength, speed, and power. The aims of this study were to investigate the relationship between cognitive factors and agility performance in this unique population. Methods: 39 young soccer players age 13.56 (SD 0.58) years were assessed for leg-muscle function (jump tests) and maturation status (peak height velocity). The Y-Agility Test, which included decision making in players, was used to measure performance. Cognitive factors such as perceptual skills and decision making were evaluated with the Y-Agility Test. Results: The linear regression showed an absence of significance between the Y-Agility Test and drop-jump contact (P =.283), Y-Agility Test and drop-jump flight (P =.185), Y-Agility Test and squat jump (P =.868), and Y-Agility Test and countermovement jump (P =.310). The linear mixed-model analyses suggested a difference between early-average maturers (P =.009) and early-late maturers (P =.005) but did not show a difference between average-late subjects (P = 1.000). Drop-jump flight did not show a difference in maturation (early-average P = 1.000; early-late P = 1.000; average P = 1.000). Squat-jump performance did not demonstrate any significance (early-average P =.618; early-late P = 1.000; P = 1.000). Countermovement-jump performance did not show any significance (early-average P = 1.000; early-late P = 1.000; average-late P =.492). Finally, agility performance does not show any significance between maturation levels (early-average maturer P =.450; early-late P = 1.000; average-late P =.830). Conclusion: Agility in young soccer players appears to follow a nonlinear trajectory, with cognitive factors possibly playing a more significant role than previously thought. [ABSTRACT FROM AUTHOR]

Objective: To (1) establish extensive physiological profiles of highly trained CrossFit® athletes using gold-standard tests and (2) investigate which physiological markers best correlate with CrossFit Open performance. Methods: This study encompassed 60 participants (30 men and 30 women), all within the top 5% of the CrossFit Open, including 7 CrossFit semifinalists and 3 CrossFit Games finalists. Isokinetic dynamometers were employed to measure maximum isometric and isokinetic leg and trunk strength. Countermovement-jump height and maximum isometric midthigh-pull strength were assessed on a force plate. Peak oxygen uptake (VO2peak) was measured by a cardiopulmonary exercise test, and critical power and W′ were evaluated during a 3-minute all-out test, both on a cycle ergometer. Results: Male and female athletes' median (interquartile range) VO2peak was 4.64 (4.43, 4.80) and 3.21 (3.10, 3.29) L·min−1, critical power 314.5 (285.9, 343.6) and 221.3 (200.9, 238.9) W, and midthigh pull 3158 (2690, 3462) and 2035 (1728, 2347) N. Linear-regression analysis showed strong evidence for associations between different anthropometric variables and CrossFit Open performance in men and women, whereas for markers of cardiorespiratory fitness such as VO2peak, this was only true for women but not men. Conventional laboratory evaluations of strength, however, manifested minimal evidence for associations with CrossFit Open performance across both sexes. Conclusions: This study provides the first detailed insights into the physiology of high-performing CrossFit athletes and informs training optimization. Furthermore, the results emphasize the advantage of athletes with shorter limbs and suggest potential modifications to CrossFit Open workout designs to level the playing field for athletes across different anthropometric characteristics. [ABSTRACT FROM AUTHOR]

Purpose: The optimal approach to hamstring training is heavily debated. Eccentric exercises reduce injury risk; however, it is argued that these exercises transfer poorly to improved hamstring function during sprinting. Some argue that other exercises, such as isometric exercises, result in better transfer to running gait and should be used when training to improve performance and reduce injury risk. Given the performance requirements of the hamstrings during the terminal swing phase, where they are exposed to high strain, exercises should aim to improve the torque production during this phase. This should improve the hamstrings' ability to resist overlengthening consequently, improving performance and limiting strain injury. Most hamstring training studies fail to assess running kinematics postintervention. Of the limited evidence available, only eccentric exercises demonstrate changes in swing-phase kinematics following training. Studies of other exercise modalities investigate effects on markers of performance and injury risk but do not investigate changes in running kinematics. Conclusions: Despite being inconsistent with principles of transfer, current evidence suggests that eccentric exercises result in transfer to swing-phase kinematics. Other exercise modalities may be effective, but the effect of these exercises on running kinematics is unknown. [ABSTRACT FROM AUTHOR]

No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0.6 m. Exercise was repeated after 14 days. Using a 3-way (set × bout × group) design, changes in GRF were assessed with analysis of variance and statistical parametric mapping. Jump height, reactive strength, peak, and mean propulsive forces declined between sets (P <.001). Vertical stiffness, contact time, force at zero velocity, and propulsive duration increased (P <.05). According to statistical parametric mapping, braking (17%–25% of the movement) and propulsive forces (58%–81%) declined (P <.05). During the repeated bout, peak propulsive force and duration increased (P <.05), while mean propulsive force (P <.05) and GRF from 59% to 73% declined (P <.001). A repeated bout of DJs differed in propulsive GRF, without changes to the eccentric phase, or effects from CG. [ABSTRACT FROM AUTHOR]

Context: The purpose of the study was to develop normative ranges and standards for knee and shoulder isokinetic and anthropometric values. These standards can be qualitatively interpreted and allow practitioners to classify isokinetic and anthropometric values more objectively for university-level netball players. Design: Posttest only observational study design. All players were only evaluated once during the in-season to generate normative ranges. Methods: A total of 51 female players volunteered. Participants were evaluated on an isokinetic dynamometer at 60° per second to obtain knee-extensor and knee-flexor values as well as shoulder-flexor and shoulder-extensor values. A total of 16 anthropometric variables were collected including stature, body mass, 8 skinfolds, and 6 circumferences. Between-group differences were calculated to determine whether playing level was a differentiating factor in data. Results: Normative standards were developed for isokinetic parameters associated with the knee and shoulder joints as well as skinfolds and circumference measures. No statistically significant between-group differences were evident (χKruskal-Wallis²[2] = 3.96, P = .140). Conclusion: These standards can be used by coaches and practitioners to set attainable goals for individual players or those from secondary leagues, classify individual and team-based performances, and facilitate decision-making processes. [ABSTRACT FROM AUTHOR]

Context: The purpose of this study was to compare short-term clinical outcomes between meniscus procedures performed with anterior cruciate ligament reconstruction (ACLR), ACLR (ACLR-only), ACLR with meniscectomy/resection (ACLR-resect), and ACLR with meniscal repair (ACLR-repair) for bone patellar tendon bone grafts (BPTB) and hamstring tendon grafts, separately. Design: This was a cross-sectional study conducted in a controlled laboratory setting as part of a large point-of-care collaborative research program. Methods: This study included 314 participants (168 females; mean [SD]: age, 19.7 [4.8]) with primary unilateral ACLR with a BPTB or hamstring tendon. Patients were divided into 3 groups depending on meniscal procedure (ACLR-only, ACLR-resect, and ACLR-repair). Postsurgical testing included: isokinetic assessment of knee extension and flexion, single-leg hop tests, and patient-reported outcomes. Multivariate analysis of covariance compared differences between meniscal procedures on the battery of tests, and for each statistically significant variable an analysis of covariance assessed the effect of meniscal procedure within each graft type. Chi-square analysis assessed the influence of meniscal procedure on tests' pass rates defined as 90% of limb symmetry index. Results: BPTB: ACLR-only had greater hamstring strength than ACLR-resect (P = .05) and ACLR-repair (P = .005). ACLR-only had the highest proportion of participants to pass the hamstring strength test (P=.02). amstring tendon: ACLR-only (P=.03) and ACLR-resect (P=.003) had higher International Knee Documentation Committee scale scores than ACLR-repair. There was a significant difference in the proportion of participants who scored >90% limb symmetry index on the timed hop test (P = .05). Conclusions: The influence of meniscal repair on clinical outcomes is dependent on the graft choice. Following an ACLR with BPTB and a meniscal procedure, hamstring function should be more closely monitored for optimal short-term recovery. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to report the reliability (intrasession) values of initial maximum push-rim propulsion (IMPRP) and sprint performance in elite wheelchair basketball (WB) players and to assess the involvement of strength in sprint capacity. Methods: Fifteen Spanish international WB male players participated in this study. The maximum single wheelchair push from a stationary position (IMPRP) and the sprint performance (ie, 3, 5, and 12 m) of WB players were measured in this study. Results: IMPRP mechanical outputs V, Vmax, P, Rel. P, F, and Rel. F variables presented high reliability values (intraclass correlation coefficient [ICC] ≥.92; coefficient of variation [CV] ≤ 8.04 ± 7.37; standard error of measurement [SEM] ≤ 29.92), but the maximum strength variables Pmax, Rel. Pmax, Fmax, and Rel. Fmax (ICC ≥.63; CV ≤ 13.19 ± 16.63; SEM ≤ 203.76) showed lower ICC values and by contrast higher CV and SEM values. The most substantial correlations were identified between maximum IMPRP values (ie, V, Vmax, P, Rel. P, F, and Rel. F) and sprint performance in 3 m (r ± confidence limits ≥ −0.74 ± 0.22, very large; R2 ≥.55), 5 m (r ± confidence limits ≥ −0.72 ± 0.24, very large; R2 ≥.51), and 12 m (r ± confidence limits ≥ −0.67 ± 0.27, large; R2 ≥.44). Conclusions: The IMPRP test and sprint tests (3, 5, and 12 m) are practical and reliable for measuring strength and speed in WB players. In addition, there were large to very large associations among strength variables (ie, P, Rel. P, F, and Rel. F) and all sprint variables. This could indicate a need to implement specific strength exercises in WB players to improve sprint capacity. [ABSTRACT FROM AUTHOR]

Purpose: The present study aimed to establish differences in load–velocity profiling, active drag (AD), and drag coefficient (Cd) between 3 age groups of female swimmers. Methods: Thirty-three swimmers (11, 13, or 16 y old) were recruited. The individual load–velocity profile was determined for the 4 competitive swimming strokes. The maximal velocity (V0), maximal load (L0), L0 normalized to the body mass, AD, and Cd were compared between the groups. A 2-way analysis of variance and correlation analysis were conducted. Results: Compared with their younger counterparts, 16-year-old swimmers generally had larger V0, L0, and AD, which was particularly evident when comparing them with 11-year-old swimmers (P ≤.052). The exception was breaststroke, where no differences were observed in L0 and AD and Cd was smaller in the 16-year-old group than the 11-year-old group (P =.03). There was a negative correlation between Cd and V0 for all groups in backstroke (P ≤.038) and for the 11-year-old group and 13-year-old group in breaststroke (P ≤.022) and front crawl (P ≤.010). For the 16-year-old group, large correlations with V0 were observed for L0, L0 normalized to the body mass, and AD (P ≤.010) in breaststroke and for L0 and AD with V0 in front crawl (P ≤.042). In butterfly, large negative correlations with V0 were observed in the 13-year-old group for all parameters (P ≤.027). Conclusions: Greater propulsive force is likely the factor that differentiates the oldest age group from the younger groups, except for breaststroke, where a lower Cd (implying a better technique) is evident in the oldest group. [ABSTRACT FROM AUTHOR]

Purpose: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force–time metrics and skating qualities in subelite female ice hockey players. Methods: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. Results: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 =.388; P =.017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 =.595; P =.001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. Conclusions: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort. [ABSTRACT FROM AUTHOR]

Purpose: Examine the reliability of field-based fitness assessments in school-aged children with emotional or behavioral difficulties (EBD). Understanding the impact of fitness on physical activity participation for children with EBD is limited by our ability to reliably measure it. Methods: Fifteen children aged 7–12 years with EBD completed 7 assessments—standing broad jump, overhead throw, grip strength, isometric plank hold, isometric wall squat, unilateral heel raise, and modified 6-minute walk test—in a random order on 2 separate occasions. Intraclass correlation coefficients (ICCs) were computed to evaluate reliability. Results: ICCs ranged from.65 to.99 representing moderate to excellent reliability for all assessments. Shorter assessments requiring less attention and behavior regulation tended to demonstrate higher ICC values while assessments with greater attention or behavioral regulation demands tended to have lower ICC values. Conclusion: Results demonstrate varied reliability for fitness tests in children with EBD. Practitioners can use grip strength and standing broad jump assessments with confidence. Other assessments have good reliability but greater variability indicating they may be a challenge for some children with EBD. [ABSTRACT FROM AUTHOR]

Studies on postactivation performance enhancement (PAPE) have used different exercises as a conditioning activity to investigate potentiation, but exclusively in upper limbs (UL) or lower (LL) limbs, or contralateral potentiation. A single exercise capable of inducing PAPE in both UL and LL is currently unknown. The present study explored the effect of the clean and jerk (C&J) as a conditioning activity for simultaneously producing PAPE interlimbs at the fourth, seventh, and 12th minutes postintervention. Twelve male weightlifters with 1-repetition maximum (1RM) in the C&J equivalent to ≥1.15 × body mass were randomly submitted to 2 experimental conditions (C&J and control [CON]). The C&J condition consisted of general warm-up (running on a treadmill and self-selected preparatory exercises) and 4 sets of 3 repetitions of C&J with 2 minutes between them (30%1RM, 50%1RM, 65%1RM, and 80%1RM) followed by a countermovement jump and a bench-press throw on a Smith machine after 4, 7, and 12 minutes, to measure the magnitude of PAPE in UL and LL. No previous exercise preceded countermovement-jump and bench-press-throw tests in the CON besides general warm-up. The main finding was that, regardless of time, the C&J resulted in greater height on countermovement jump and Smith machine bench-press throw when compared with the CON, presenting a similar effect size between UL and LL (34.6 [3.9] vs 33.4 [4.1] cm [+3.66%]; P =.038; effect size = 0.30 and 30.3 [4.7] vs 29.0 [5.1] cm [+4.44%]; P =.039; effect size = 0.26), respectively. Thus, C&J can be useful to produce PAPE simultaneously among members. [ABSTRACT FROM AUTHOR]

Across many species, a major function of vocal communication is to convey formidability, with low voice frequencies traditionally considered the main vehicle for projecting large size and aggression. Vocal loudness is often ignored, yet it might explain some puzzling exceptions to this frequency code. Here we demonstrate, through acoustic analyses of over 3,000 human vocalizations and four perceptual experiments, that vocalizers produce low frequencies when attempting to sound large, but loudness is prioritized for displays of strength and aggression. Our results show that, although being loud is effective for signaling strength and aggression, it poses a physiological trade-off with low frequencies because a loud voice is achieved by elevating pitch and opening the mouth wide into a-like vowels. This may explain why aggressive vocalizations are often high-pitched and why open vowels are considered "large" in sound symbolism despite their high first formant. Callers often compensate by adding vocal harshness (nonlinear vocal phenomena) to undesirably high-pitched loud vocalizations, but a combination of low and loud remains an honest predictor of both perceived and actual physical formidability. The proposed notion of a loudness-frequency trade-off thus adds a new dimension to the widely accepted frequency code and requires a fundamental rethinking of the evolutionary forces shaping the form of acoustic signals. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The present work aims to elucidate the effect of process parameters and pin length on microstructure and the characteristics, distribution of intermetallic compounds (IMCs), and associated failure initiation and progress pattern of AA7075 friction stir lap weld (FSLW) joints prepared employing copper interlayer. FSLW joints obtained using various combinations of tool rotation (900 and 1200 rpm), weld speeds (63 and 98 mm/min), and pin lengths (3 mm and 4 mm) are tested for tensile shear strength, fracture behavior, and the influence of IMCs formed are appraised. Further, the elastic modulus and hardness of the IMCs and neighborhood are evaluated using nanoindentation tests to correlate with the joint performance. The non-uniform thickness of AlCu, Al2Cu, and Al4Cu9 IMCs is formed due to intermixing of Al and Cu whose thickness varied with process parameters. Higher elastic modulus and hardness are recorded at the IMCs. FSLW joint prepared with 1200 rpm tool rotation, 63 mm/min weld speed, and 4 mm pin length results in better joint formation and higher strength, wherein an IMC layer thickness of around 3–4.3 µm is measured near the hook region. [ABSTRACT FROM AUTHOR]

The aim of the present study was to develop prediction equations for the one repetition maximum (1RM) Bench Press (BP) in resistance-trained men based on muscle thickness and simple anthropometric parameters. 83 men (age: 26.2 ± 4.9y, height: 175.9 ± 6.3 cm, body mass: 82.9 ± 11.2 kg) participated in the present investigation and were assessed for anthropometric measurements and for muscle thickness of pectoral major (MTP). Then, the participants performed the 1RM BP test. A very large correlation was detected between MTP and 1RM BP (r = 0.83–0.88). A prediction equation based on MTP and body mass (EQ1) was developed: 1RM BP = –15.2460565 + (32.0751388 * MTP) + (0.6364405 * Body Weight) with R2 = 0.79. Another prediction equation was developed using MTP only (EQ2): 1RM BP = 20.36167 + (39.36532 * MTP) with R2 = 0.69. Bland-Altman analysis and paired sample t test provided insufficient evidence to support differences between the predicted and the measured 1RM BP in both the equations (p > 0.05). This study showed that both MTP based (EQ2) and MTP and body mass based (EQ1) methods can be used to predict 1RM BP and may represent important tools for the evaluation of maximal strength. These findings support the potential use of non-performance-based parameters to predict maximal dynamic strength in trained individuals. [ABSTRACT FROM AUTHOR]

The aim of this paper is to review the developments in the use of superabsorbent polymer (SAP) in cementitious materials. This review covers the classification, properties, and methods for testing SAP, along with its impact on concrete properties, and other noteworthy developments in SAP usage. Various methods can be used to test the water absorption by SAP. Among them, the tea bag method is considered a simple and time-saving test, while centrifuge and suction filtration methods are regarded as accurate because they remove inter-particle liquid. The water absorption by SAP is affected by factors such as SAP composition, method of preparation, physical characteristics, and properties of the fluid. Higher fluid temperature (e.g., 60 °C) leads to greater absorption and release distance, while higher pH levels (pH 13) result in lesser absorption. The optimal dosage of SAP varies between studies, generally ranging from 0.1% to 1.5%. Higher SAP content (0.3–8%) reduces workability and decreases slump. Results related to strength vary; some studies have reported increased strength due to SAP's maintenance of higher internal relative humidity, while others have observed decreased strength due to increased porosity caused by SAP. The inclusion of SAP typically leads to a strength recovery of about 10% over time due to the continuous hydration process. Curing methods also influence strength, with sealed curing showing greater strength. Additionally, an increase in SAP dosage (0.1–0.6%) reduces shrinkage. Furthermore, the paper discusses the challenges encountered while using and testing SAP, as well as the explanations provided by researchers. [ABSTRACT FROM AUTHOR]

Highlights Assessing the mechanical properties of CFRP and aluminum specimens exposed to hygrothermal aging is vital. Moreover, it is important to develop strategies to improve these properties. This study examines the influence of fullerene and Single‐Walled Carbon Nanotubes (SWCNT) on the fatigue life and static strength of bonded and bonded/bolted joints. The research concentrates on composite‐to‐composite and composite‐to‐aluminum substrates under three‐point bending tests, both prior to and after hygrothermal aging. The samples were classified into four groups: (1) neat specimens, (2) specimens with added fullerene, (3) specimens containing SWCNT, and (4) specimens with a blend of 50% SWCNT and 50% fullerene.The findings indicated that the optimal nanoparticle ratio for bonded joints differs from that for bonded/bolted joints. Incorporating nanoparticles into the adhesive enhanced the fatigue life of single lap joints (SLJs), particularly in samples with mixed particles and SWCNT. In some instances, nanoparticles intensified the effects of hygrothermal conditions, further increasing fatigue life. The incorporation of nanoparticles and the use of bonded/bolted joints significantly enhanced joint strength, with the combination of both yielding the best results. This study improves the understanding of aging in adhesive and hybrid joints, particularly in dissimilar configurations, and offers insights into their performance under various environmental conditions. Study examines fullerene and SWCNT impacts on CTC/CTA joint strength and fatigue. Optimal nanoparticle ratios differ for bonded and bonded/bolted joints. Nanoparticles reduce moisture absorption, aging damage, and increase failure load. Nanoparticles enhance fatigue life, varying by type, volume, load, and joint. Incorporating nanoparticles significantly improves joint strength. [ABSTRACT FROM AUTHOR]

Exercise physiology and circadian biology are distinct and long-standing fields. Recently they have seen increased integration, largely due to the discovery of the molecular components of the circadian clock and recognition of human exercise performance differences over time-of-day. Circadian clocks, ubiquitous in cells, regulate a daily tissue specific program of gene expression that contribute to temporal patterns of physiological functions over a 24-h cycle. Understanding how circadian clock function in skeletal muscle, as well as other tissues contribute to exercise performance is still in the very early stages. This review provides background on this emerging field with a review of early exercise and time-of-day studies in both human and animals. We then move into the role of the circadian clock and its daily program of gene expression in skeletal muscle with a focus on specific metabolic and physiological outputs that vary over time-of-day. Lastly, we discuss the recognition that the timing of exercise communicates with the skeletal muscle circadian clock to adjust its phase settings and why this maybe important for performance and health. [Display omitted] • The Circadian clock is a molecular mechanism temporally orchestrating mammalian physiological functions on a 24-h cycle. • Exercise performance exhibits diurnal patterns, which peaks in the late afternoon/evening (16:00–19:00 h). • The timing of exercise serves as a zeitgeber, shifting clock phase to promote alterations in metabolism and clock output. • Exercise-induced phase shifts in the muscle clock occur independently and do not affect SCN circadian rhythms. [ABSTRACT FROM AUTHOR]

The design of a tube-beam front subframe was optimized to meet performance and lightweight requirements. Firstly, a 3D mesh model of the subframe was established using HyperMesh software, and the optimization space was determined through sensitivity analysis. Then, the topology optimization was conducted using Optistruct analysis software to determine the layout of the subframe and the optimal position of the cross member. By comparing the performance of the subframe before and after conducting topology optimization under various working conditions, it was observed that the static stiffness at the most critical points of the optimized subframe was significantly improved. Additionally, the strength and modal characteristics were enhanced. Finally, the optimized scheme was verified through bench tests with high accuracy and feasibility, providing a valuable reference for future tube-and-beam subframe design. [ABSTRACT FROM AUTHOR]

DUX4 is the major gene responsible for facioscapulohumeral dystrophy (FSHD). Several mouse models expressing DUX4 have been developed, the most commonly used by academic laboratories being ACTA1-MCM/FLExDUX4. In this study, molecular and histological modifications in the tibialis anterior and quadriceps muscles were investigated in this model at different time points. We investigated several changes that could be used as markers of therapeutic efficacy. Our results confirm the progressive muscular dystrophy previously described but also highlight biases associated with tamoxifen injections and the complexity of choosing the genes used to calculate a DUX4-pathway gene composite score. We also developed a comprehensive force test that better reflects the movements made in everyday life. This functional force–velocity–endurance model, which describes the force production capacities at all velocity and fatigue levels, was applied on 12–13-week-old animals without tamoxifen. Our data highlight that previously unsuspected muscle properties are also affected by the expression of DUX4, leading to a weaker muscle with a lower initial muscle force but with preserved power and endurance capacity. Importantly, this force–velocity–endurance approach can be used in humans for clinical evaluations. [ABSTRACT FROM AUTHOR]

The strength of ultra-low carbon maraging stainless steels can be significantly enhanced by precipitating nanoscale intermetallic secondary phases. Retained or reversed austenite in the steel can improve its toughness, which is key to achieving an ideal combination of strength and toughness. Ti and Al are often used as cost-effective strengthening elements in maraging stainless steels but the synergistic toughening and strengthening mechanisms of Ti and Al have not been studied. To investigate the synergistic toughening and strengthening mechanisms of Ti and Al in Co-free maraging stainless steels, this paper focuses on the microstructure and mechanical properties of three alloys: Fe-12Cr-11Ni-1.7Al-0.5Ti (Steel A), Fe-12Cr-11Ni-0.5Ti (Steel B), and Fe-12Cr-11Ni-1.7Al (Steel C). The impact of Ti and Al on the microstructure and mechanical properties was investigated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), and thermodynamic simulations. The relationship between microstructure, strength, and toughness is also discussed. The results indicated that Steel A, containing both Al and Ti, exhibited the highest strength level after solution treatment at 900 °C, with an ultimate tensile strength reaching 1571 MPa after aging at 540 °C. This is attributed to the simultaneous precipitation of spherical β-NiAl and rod-shaped η-Ni3Ti phases. Steel B, with only Ti, formed a significant amount of Ni-rich reversed austenite during aging, reducing its ultimate tensile strength to 1096 MPa. Steel C, with only Al, showed a high strength–toughness combination, which was achieved by forming dispersive nano-sized intermetallic precipitates of β-NiAl in the martensitic matrix with a slight amount of austenite. It is highlighted that Al has superior toughening and strengthening effects compared to Ti in the alloy system. [ABSTRACT FROM AUTHOR]

An effective type of polymer heat-insulating material (foams) based on reactive oligomers is casting epoxy foams with high technological and operational parameters. However, polyepoxide foams are highly flammable, which significantly restrains their application in the construction industry. The aim of this work was to develop effective methods for reducing the flammability of filling epoxy foams. In order to achieve the objective, the following objectives were addressed: determining the influence of the chemical nature and content of additive and reactive bromine- and phosphorus-containing compounds on the thermal stability, flammability and operational properties of filling epoxy foams, and the development of polyepoxy foams of reduced flammability with high-quality physical and mechanical characteristics. When estimating the flammability of epoxy foams, we used both state-approved methods and the methods described in scientific and technical literature. The thermal properties of epoxy foams were studied with the help of multimodular thermoanalytical complex DuPont-9900. The data on the influence of the apparent density of foams and oxygen concentration in the oxidant flow on the flame propagation speed on the horizontal surface of polyepoxy foams are presented. It was revealed that the chemical nature of amine hardeners does not affect the thermal stability and flammability of epoxy foams. It was established that phosphate plasticizers are ineffective flame retardants of foamed epoxy resin, and the chemical structure of additive organobromic flame retardants insignificantly affects their efficiency. It was shown that microencapsulated flame retardants are inferior in flame retardant efficiency to additive flame retardants. It was found that effective flame retardants for casting polyepoxy foams are phosphorus-containing oligoether methacrylate and epoxidized waste from the production of tetrabromodiphenylpropane. The results of this research will form the basis for the production of an experimental industrial batch of samples of pouring epoxy foams of reduced flammability. [ABSTRACT FROM AUTHOR]

The extraction of mining resources, as well as processing processes such as ore beneficiation and smelting, generate large amounts of tailings that are difficult to directly utilize. Meanwhile, substantial filling materials are required for the voids formed after mining operations, and the environmental issues and safety hazards brought on by massive solid waste disposal cannot be ignored. By utilizing solid waste with alkaline and pozzolanic activity as the binder component and gold tailings as filler aggregate to prepare filler material to fill up the void areas, the purpose of waste treatment can be achieved. In this study, salt sludge, steel slag, ground granulated blast furnace slag, and gold tailings were used to prepare all-solid waste fluidized filling material for filling mine void areas, which not only solves the engineering safety problem of easy collapse of the mine airspace in the mining process but also ensures a backfill effect with high strength, which continuously guarantees the uninterrupted progress of the mining project. At the same time, the preparation of fluidized materials can consume a large amount of tailings and other solid waste, solving the problem of their stockpiling. The components of the solid wastes used are all general industrial solid wastes, so the preparation of the fluidized materials will not have an impact on the surrounding environment. The effects of binder ratios on the workability of the filling materials were investigated by means of the slump and slump flow tests. Combined with the unconfined compressive strength test, the change in backfill material strength with curing age and the water–binder ratio was studied. The experimental results showed that the slump and slump flow value of the filling material were positively correlated with the water–binder ratio. The water–binder ratio range satisfying a slump value of 180~260 mm and a slump flow value not less than 400 mm was 0.95~1.106. However, the strength decreased with the increase in the water–binder ratio, conforming to a hyperbolic relationship. The all-solid waste fluidized filling material had strengths not less than 0.22, 1.09, and 1.95 MPa at 3, 7, and 28 d, respectively, meeting the workability requirements. Finally, a method for determining the optimal range of water–binder ratio considering both workability performance and strength is proposed based on the relationship between slump value, slump flow value, unconfined compressive strength, and the water–binder ratio. [ABSTRACT FROM AUTHOR]

Strong relationships exist between sprint cycling torque and isometric mid‐thigh pull (IMTP) force production at one timepoint; however, the relationships between the changes in these measures following a training period are not well understood. Accordingly, this study examined the relationships in the changes of sprint cycling torque and IMTP force following six‐weeks of sprint cycling and resistance training performed by strength‐trained novice cyclists (n = 14). Cycling power, cadence, torque and IMTP force (Peak force [PF]/torque, average and peak rate of force/torque development [RFD/RTD], and RFD/RTD from 0 to 100 ms and 0–200 ms) were assessed before and after training. Training consisted of three resistance and three sprint cycling sessions per week. Training resulted in improvements in IMTP PF (13.1%) and RFD measures (23.7%–32.5%), cycling absolute (10.7%) and relative (10.5%) peak power, peak torque (11.7%) and RTD measures (27.9%–56.7%). Strong‐to‐very strong relationships were observed between cycling torque and IMTP force measures pre‐ (r = 0.57–0.84; p < 0.05) and post‐training (r = 0.63–0.87; p < 0.05), but no relationship (p > 0.05) existed between training‐induced changes in cycling torque and IMTP force. Divergent training‐induced changes in sprint cycling torque and IMTP force indicate that these measures assess distinct neuromuscular attributes. Training‐induced changes in IMTP force are not indicative of training‐induced changes in sprint cycling torque. Highlights: Six weeks of resistance and sprint cycling training resulted in improvements in isometric mid‐thigh pull (IMTP) peak force (13.1%) and rate of force development measures (23.7%–32.5%), cycling absolute (10.7%) and relative (10.5%) peak power, peak torque (11.7%), and rate of torque development measures (27.9%–56.7%) in strength‐trained novice cyclists.No significant relationships were observed between the training‐induced changes in IMTP force measures and sprint cycling torque measures following training.No significant relationships were observed between the training‐induced changes in cycling peak power and changes in cycling torque, IMTP force, back squat and trap bar deadlift with three repetition maximum. [ABSTRACT FROM AUTHOR]

Purpose: While muscle mass and skeletal muscle fibers phenotype have been shown atypical in constitutional thinness (CT), force production capacities and its architectural determinants have never been explored. The present study compared muscle functionality and architecture between participants with CT and their normal-weight (NW) counterparts. Methods: Anthropometry, body composition (Dual-X-ray Absorptiometry), physical activity/sedentary behavior (ActiGraph wGT3X-BT), ultrasound recording of the Vastus Lateralis (2D-ultrasound system), and functional capacities at maximal isometric and isokinetic voluntary contractions (MVCISO and MVCCON) during knee extension (isokinetic dynamometer chair Biodex) have been measured in 18 women with CT (body mass index < 17.5 kg/m2) and 17 NW women. Results: A lower fat-free mass (ES: −1.94, 95%CI: −2.76 to −1.11, p < 0.001), a higher sedentary time, and a trend for a lower time spent at low-intensity physical activity, were observed in CT vs NW participants. While absolute MVCISO, MVCCON, rate of torque development (RTD), and torque work were all markedly lower in CT, these differences disappeared when normalized to body or muscle mass. Muscle thickness and fascicle length were found lower in CT (ES: −1.29, 95%CI: −2.03 to −0.52, p < 0.001; and ES: −0.87, 95%CI: −1.58 to −0.15, p = 0.02, respectively), while pennation angle was found similar. Conclusion: Despite lower absolute strength capacities observed in CT, present findings support the hypothesis of physiological adaptations to the low body and muscle mass than to some intrinsic contractile impairments. These results call for further studies exploring hypertrophy-targeted strategies in the management of CT. [ABSTRACT FROM AUTHOR]

Isokinetic knee tests mostly evaluate reciprocal concentric-concentric flexor-extensor movements in a seated position. Discrete tests generate higher moments, but time requirements impede their widespread implementation. This study examined if hip angle (flexed vs. extended) and test modality (discrete vs. reciprocal) affect camera-based data (100 fps). Sixteen healthy males performed concentric (con) and eccentric (ecc) isokinetic knee flexor (H) and extensor (Q) movements (60°/s). Peak moments and contractional work of discrete and reciprocal tests (QconQecc, HconHecc) strongly correlated for extended (Q:91%≥R2≥71%; H:95%≥R2≥87%) and flexed hip (Q:88%≥R2≥70%; H:81%≥R2≥75%) without significant differences (p>0.05) between test modalities. Discrete and "traditional" seated QconHcon-tests revealed substantially lower correlations for extended (Q:44%≥R2≥43%; H:55%≥R2≥54%) and flexed hip (Q:81%≥R2≥77%; H:48%≥R2≥47%). Although most mean values did not significantly differ, moderate correlations were predominant and the respective limits of agreement demonstrated considerable effects of hip angle and test modality. These insights assist practitioners in interpreting isokinetic data of different test procedures. If time constraints prevent discrete knee tests (gold standard), concentric-eccentric movements provide highly correlated outcomes, independent of the hip angle. [ABSTRACT FROM AUTHOR]

Composite sandwich structures, which are widely employed in engineering structures, require a multitude of inserts. In certain instances, the necessity for a specialized insert arises from the unique characteristics of a particular application. In applications such as weather radar radomes, double-curved sandwich panels should be designed with electromagnetic (EM) transparency as a primary objective. The use of metal inserts should be restricted to the absolute minimum. Given the limitations of using metal materials to protect against EM radiation and the need to enhance the load-bearing capacity of the joint against pull-out loads, a composite insert has developed as an innovative solution. In this study, a composite insert of a double-curved sandwich dome has been developed using silica nanoparticles, and its mechanical strength against pull-out load has been evaluated through both experimental and numerical analysis. The strength results obtained have been compared with analytical estimates. Additionally, the buckling of the double-curved sandwich dome against a wind speed of 220 km/h has been investigated numerically. The critical buckling load for wind loading for the full-scale sandwich radome was estimated to be 16,303 N. According to the numerical results obtained with the Abaqus finite element (FE) software, the maximum pull-out force applied to the connection area is approximately 10.7 kN. A parametric study of geometric variables and experimental results showed that it is possible to achieve a stronger composite insert (by 1 wt % nano silica particles) by 20.7% lighter and 102.65% more bearing capacity. [ABSTRACT FROM AUTHOR]

High-purity SiC ceramic membrane has gained tremendous attention in the treatment of various corrosive wastewaters. Additive manufacturing technique makes it possible to fabricate high-purity SiC ceramic membrane with complex configurations. Here, we proposed a route for the preparation of high-purity SiC ceramic membrane support using digital light processing and SiC whisker reinforcement. With the increase of whisker content, the viscosity of SiC w /SiC photosensitive slurry increased due to the formation of whiskers agglomerations; the average pore size shifted from 3.15 μm to 1.35 μm with the occupation of large pores by SiC whiskers. In addition, the compressive strength of the ceramic support increased from 10.7 MPa to 16.7 MPa because of the decline in pore size and the toughening effects by SiC whiskers. So, the introduced SiC whiskers enhanced the pore connectivity and mechanical strength of the porous ceramics. This work provides a feasible path to manufacture high-purity SiC ceramic membrane support with complex configuration, high pore-connectivity and excellent mechanical properties. [ABSTRACT FROM AUTHOR]

This study examined the association between physical activity level, cardiorespiratory fitness, musculoskeletal strength, and driving outcomes in a driving simulator, while accounting for cognitive processing speed. Sixty-nine young drivers completed simulated driving scenarios of varying complexity. They also completed selfreport measures of physical activity, and their processing speed, musculoskeletal strength, and cardiorespiratory fitness were assessed using standardized measures. Participants who were more physically active reacted significantly faster to a braking task while driving on a straight road. The group of participants that was deemed more physically fit based on an indicator of cardiorespiratory fitness were found to crash less often. Low fit participants also presented significantly higher odds of having a crash. Participants with lower grip strength also showed a lower odd of crashing This study supports the notion that physical fitness, particularly cardiorespiratory fitness and strength, is crucial for swift behavioral responses under pressure while driving. [ABSTRACT FROM AUTHOR]

Dynamic cone penetrometer (DCP) has been commonly used for the evaluation and quality control/assurance of soils before, during, and after construction in civil engineering projects. This test equipment has been increasingly used for geotechnical engineering applications but not yet been used to evaluate lightweight cellular concrete (LCC) as a backfill material. This technical note reports laboratory and field DCP tests to evaluate the properties of LCC. To establish the relationship between DCP data and other material properties, unconfined compressive strength and California bearing ratio (CBR) tests were conducted on this material. The test results showed that the measured unconfined compressive strength and CBR of LCC increased as its density increased. The DCP indices (DCPI) for the LCC specimens at different densities were almost constant with the penetration depth. This technical note proposes the correlations between the DCPI and the unconfined compressive strength and CBR, which may be used for future applications. [ABSTRACT FROM AUTHOR]

Researchers have explored the utilization of nanoparticles to improve the properties of soils for various geotechnical construction applications. However, the potential of nanoparticles and their mechanisms of action in enhancing the behavior of industrial byproduct pozzolanic materials has not been properly examined. Hence, in the present study, we aimed to investigate and optimize montmorillonite nanoclay (m-NC) content to improve the engineering properties (unconfined compressive strength, compressibility and permeability) of fly ash with and without lime treatment. In addition, we examined the leaching potential of metal ions through m-NC amended with untreated and lime-treated fly ash by performing leachate column and inductively coupled plasma mass spectrometry (ICP-MS) tests. The mechanisms of change in the engineering properties of lime-treated fly ash with m-NC were uncovered through several microlevel investigations. The results revealed that the strength of untreated and lime-treated fly ash was enhanced significantly with the addition of m-NC. Furthermore, the addition of m-NC to fly ash led to increased compressibility but in same time, it reduces for lime-treated fly ash. However, the permeability of untreated and lime-treated fly ash decreased with the addition of m-NC. The leaching potential of metal ions decreased significantly with the addition m-NC to fly ash. Microlevel investigations confirmed the plate-like fine particles having higher specific surface area of m-NC, improvement in gradation with filling of voids and acceleration in pozzolanic reactivity and thereby formation of silicate and aluminate hydrated cementitious compounds are the key factors in controlling the behavior of lime-treated fly ash with m-NC content. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass production implemented using PIM. Thus, the surface properties and mechanical performance of parts produced using powder/polymer binder feedstocks [material extrusion (MEX) and PIM] were investigated and compared with powder manufacturing based on direct metal laser sintering (DMLS). Design/methodology/approach: PIM parts were manufactured from 17-4PH stainless steel PIM-quality powder and powder intended for powder bed fusion compounded with a recently developed environmentally benign binder. Rheological data obtained at the relevant temperatures were used to set up the process parameters of injection molding. The tensile and yield strengths as well as the strain at break were determined for PIM sintered parts and compared to those produced using MEX and DMLS. Surface properties were evaluated through a 3D scanner and analyzed with advanced statistical tools. Findings: Advanced statistical analyses of the surface properties showed the proximity between the surfaces created via PIM and MEX. The tensile and yield strengths, as well as the strain at break, suggested that DMLS provides sintered samples with the highest strength and ductility; however, PIM parts made from environmentally benign feedstock may successfully compete with this manufacturing route. Originality/value: This study addresses the issues connected to the merging of two environmentally efficient processing routes. The literature survey included has shown that there is so far no study comparing AM and PIM techniques systematically on the fixed part shape and dimensions using advanced statistical tools to derive the proximity of the investigated processing routes. [ABSTRACT FROM AUTHOR]

This investigation was aimed at finding the optimum replacement level of waste brick powder (WBP) as a partial replacement of cement. For this purpose, three groups of tests are made: fresh, mechanical, and permeation properties. Eight mixes with different percentages of replacing ratios are as follows: 10, 15, 20, 25, 30, 35, 40, and 50%. In addition to the reference mix without powder replacements, the experimental programs include three groups of tests: fresh properties (flow test and fresh density), mechanical properties (dry density, compressive strength, and flexural strength), and transport properties (water absorption ratio, rate of water absorption, i.e., sorptivity, and permeable void ratio). Also, an ultrasonic velocity impulse test was made. The flowability and density of fresh mixes are decreased linearly as the amount of WBP increases for the constant water/binder ratio. However, the density of the in-hardened state was found to be slightly higher than the reference mix for mixes with a brick powder content of up to 20%. Results indicate that strengths for mixes containing WBP are higher than those for the control mix. The highest strength was examined in the mix with 15% WBP for both compressive and tensile strengths of specimens. Generally, the brick powder reduced the ability of mortar to transfer liquid, as was clear from the results of the permeability test results. Empirical relations were proposed according to experimental results. [ABSTRACT FROM AUTHOR]

• Relationships between skeletal muscle echogenicity and physical function were small to moderate but highly consistent. • Sub-analyses determined minimal between-muscle differences in predictive ability. • Ultrasonic echogenicity should be considered part of early detection screens for sarcopenia and other diseases. • Combining muscles tended to strengthen the model, although muscle quality appears systemic, allowing for a single scan to represent the total body. Assessment and quantification of skeletal muscle within the aging population is vital for diagnosis, treatment, and injury/disease prevention. The clinical availability of assessing muscle quality through diagnostic ultrasound presents an opportunity to be utilized as a screening tool for function-limiting diseases. However, relationships between muscle echogenicity and clinical functional assessments require authoritative analysis. Thus, we aimed to (a) synthesize the literature to assess the relationships between skeletal muscle echogenicity and physical function in older adults (≥60 years), (b) perform pooled analyses of relationships between skeletal muscle echogenicity and physical function, and (c) perform sub-analyses to determine between-muscle relationships. CINAHL, Embase, MEDLINE, PubMed, and Web of Science databases were systematically searched to identify articles relating skeletal muscle echogenicity to physical function in older adults. Risk-of-bias assessments were conducted along with funnel plot examination. Meta-analyses with and without sub-analyses for individual muscles were performed utilizing Fisher's Z transformation for the most common measures of physical function. Fisher's Z was back-transformed to Pearson's r for interpretation. Fifty-one articles (n = 5095, female = ∼2759, male = ∼2301, 72.5 ± 5.8 years, mean ± SD (1 study did not provide sex descriptors)) were extracted for review, with previously unpublished data obtained from the authors of 13 studies. The rectus femoris (n = 34) and isometric knee extension strength (n = 22) were the most accessed muscle and physical qualities, respectively. The relationship between quadriceps echogenicity and knee extensor strength was moderate (n = 2924, r = –0.36 (95% confidence interval: –0.38 to –0.32), p < 0.001), with all other meta-analyses (grip strength, walking speed, sit-to-stand, timed up-and-go) resulting in slightly weaker correlations (r : –0.34 to –0.23, all p < 0.001). Sub-analyses determined minimal differences in predictive ability between muscle groups, although combining muscles (e.g., rectus femoris + vastus lateralis) often resulted in stronger correlations with maximal strength. While correlations are modest, the affordable, portable, and noninvasive ultrasonic assessment of muscle quality is a consistent predictor of physical function in older adults. Minimal between-muscle differences suggest that echogenicity estimates of muscle quality are systemic. Therefore, practitioners may be able to scan a single muscle to estimate full-body skeletal muscle quality/composition, while researchers should consider combining multiple muscles to strengthen the model. [Display omitted] [ABSTRACT FROM AUTHOR]

For almost a decade, various studies have been carried out to prove the suitability of nano additives in enhancing the geotechnical properties of soil. Yet, this line of research is still in its elementary stage, restricting itself to laboratory tests to determine soil's index and engineering properties blended with varying dosages of nano additives. In other words, research on practical applications of nano additives for soil stabilization is scarce. The present work attempts to investigate the suitability of three different nanomaterials as a load-bearing stratum for shallow foundations. The nano additives were chosen in such a way that each of them is from a different origin. One of them is nano calcium carbonate (inorganic) whereas the other two are nano-sized varieties of natural biopolymers, namely nano chitosan (crustacean-based) and nano carboxymethyl cellulose (plant-based). A series of laboratory tests were initially conducted to determine the strength of all three nano-additive-treated soils at different dosages, which were investigated for 180 days to ensure their long-term performance. This was followed by a foundation model study on untreated soil and on soil treated with optimal dosages of nano additives. The results were validated using finite element software followed by a parametric study to optimize the depth of soil stabilization. It was observed that all three nano additives exhibited a better performance when the top layer had the optimal dosage and the subsequent layers had a relatively lesser dosage. [ABSTRACT FROM AUTHOR]

Using adhesively bonded joints is an effective strategy for achieving lightweight designs. However, understanding the long‐term performance of these bonded joints remains a critical concern. Creep is a time‐dependent phenomenon induced by sustained mechanical loads, which can lead to viscous strain in adhesive materials. This strain has the potential to cause cracking in bonded structures over time. This study aims to investigate the creep and post‐creep behaviors of adhesively bonded aluminum joints, focusing on two crucial parameters: creep load level and creep duration. Butt adhesive joint (BAJ) specimens were fabricated and exposed to varying creep loads and times. Subsequently, quasi‐static tensile tests were conducted to assess the residual mechanical properties. The results indicated that higher creep loads resulted in increased creep deformations at constant creep durations. Furthermore, a downward trend was observed in the residual tensile mechanical properties of BAJ specimens following creep. Specifically, higher creep load levels and longer times led to more pronounced reductions in joint strength, strain, and stiffness. These reductions in joint mechanical properties were corroborated through joint fracture surface analysis. Additionally, mathematical models were developed using response surface methodology (RSM) to predict the experimental joint residual mechanical properties under different creep loads and times. Highlights: Investigation of creep and post‐creep behaviors in adhesive joints.Higher creep load levels result in greater joint permanent deformations.Impact of higher creep load levels and durations on joint failure strength.Decreasing in the joint deformability and stiffness after creep. [ABSTRACT FROM AUTHOR]

The concept of sustainability has become a crucial concern for safeguarding the planet. The current research has focused on developing affordable and eco-friendly mortar by using industrial wastes. This study explores the use of fly ash (FA) and ground granulated blast furnace slag (GGBFS), byproducts of steelmaking and coal burning, in mortar production. It examines their impacts on the compressive strength and setting times, when utilizing varying proportions of the materials. The study also evaluates water requirements for the workability, thus demonstrating the sustainability of these waste products in construction. The cementitious materials were employed in finely ground form and were replaced with further tertiary mixes including both supplements at 10%, 30%, and 50% of each. The mixtures were allowed to cure for 7, 14, and 28 days by immersion in water. The results showed improvements in the compressive strength of mortar samples incorporating FA and GGBFS at various curing ages. However, the water requirement and workability of mortar samples were altered as a result of utilizing these supplementary cementitious materials (SCMs). These findings will serve as a standard for environmentally responsible mortar using GGBFS and/or FA as SCMs. [ABSTRACT FROM AUTHOR]

The purpose of the work is to present issues related to the influence of surface treatment on the strength of adhesive joints of C45 steel sheets by grinding based on experimental research. These issues were related to determining the impact of the gradation and type of abrasive material on the strength of adhesive joints of the steel sheets. The grinding was carried out manually using an angle grinder with a disc diameter of 125 mm and a rotational speed of 11.060 min-1, using abrasive materials with grains made of: ceramics, zirconium and electro-corundum with a gradation of P40, and sandpaper with grains made of electro-corundum with various grain sizes with three gradations P40, P220, P400 (according to European FEPA standards). To make the adhesive joints of steel sheets, the epoxy adhesive was used, which contains an epoxy resin based on bisphenol A and a triethyleneteramine curing agent. A profilographometer from Hommel - Etamic was used to determine selected 2D and 3D surface roughness parameters, and the strength tests of the steel sheets adhesive joints were performed on a ZWICK/ROELL Z150 testing machine. The analysis of the tests showed a significant impact of the surface treatment method on the attained shear strength of the steel sheets adhesive joints. Comparing the samples prepared with electrocorundum of the variable gradation, the tests exhibited that the samples prepared with P40 paper had the highest roughness, while samples prepared with P400 paper had the highest shear strength. Roughness analysis indicated that in the comparison group of samples prepared with abrasives of the various abrasive materials, ceramics showed the highest roughness parameters and the shear strength of the adhesive joints after this treatment. [ABSTRACT FROM AUTHOR]

Cemented tailings backfill (CTB) not only boosts mining safety and cuts surface environmental pollution but also recovers ores previously retained as pillars, thereby improving resource utilization. The use of alternative reinforcing products, such as steel fiber (SF), has continuously strengthened CTB into SFCTB. This approach prevents strength decreases over time and reinforces its long-term durability, especially when mining ore in adjacent underground stopes. In this study, various microstructure and strength tests were performed on SFCTB, considering steel fiber ratio and electromagnetic induction strength effects. Lab findings show that combining steel fibers and their distribution dominantly influences the improvement of the fill's strength. Fill's strength rises by fiber insertion and has an evident correlation with fiber insertion and magnetic induction strength. When magnetic induction strength is 3 × 10−4 T, peak uniaxial compressive stress reaches 5.73 MPa for a fiber ratio of 2.0vol%. The cracks' expansion mainly started from the specimen's upper part, which steadily expanded downward by increasing the load until damage occurred. The doping of steel fiber and its directional distribution delayed crack development. When the doping of steel fiber was 2.0vol%, SFCTBs showed excellent ductility characteristics. The energy required for fills to reach destruction increases when steel-fiber insertion and magnetic induction strength increase. This study provides notional references for steel fibers as underground filling additives to enhance the fill's durability in the course of mining operations. [ABSTRACT FROM AUTHOR]