Role Of Strength Research Articles

Callous-Unemotional Traits and Conduct Problems in Children: The Role of Strength and Positive Characteristics.

In recent decades, many researchers have focused on the development of Conduct Problems from childhood to adolescence. Understanding behavior problems also requires an understanding of well-regulated characteristics. Focusing our assessment on strengths makes it possible, on the one hand, to help children or adolescents with deficits in important areas (e.g., socio-emotional deficits) to develop emotional regulation skills and adapt their responses to different contexts. This study aims to understand the role of self-competence, self-regulation, empathy, and responsibility (strength variables) in the relationship between Callous Unemotional characteristics and Conduct Problems, with a sample of 236 children aged between 3 and 10 years (M = 7.51, SD = 1.63), through mediation analysis. In general, our findings suggest that self-regulation significantly explains the relationship between the callous dimension of the Inventory of Callous-Unemotional Traits and Conduct Problems, pointing out that this strength variable seems to act as a protective factor against the development of behavior problems. No other mediation effects were found, and these results are considered in light of some limitations.

W2AlC: A new layered MAX phase to adjust the balance between strength and ductility

To adjust the balance between the strength and ductility of high-temperature material, we apply the first-principles calculations to explore the structural feature, elastic modulus and brittle or ductile behavior of M2AlC (M = Mo, Cr and W) layered structure MAX phase. In addition, the thermodynamic properties of M2AlC carbides are also discussed. The calculated results show that two novel M2AlC carbides: Mo2AlC and W2AlC are predicted. For M2AlC carbide, the M − C bond in layered structure plays an important role in strength and ductility. In particular, the W2AlC exhibits better ductility in while has high elastic modulus. Naturally, the strength and ductility of W2AlC are related to the bond strength and bond orientation of W–C bond in (W–C)–Al-(W–C) layered structure. The weak bond strength of W–C bond in shear direction improves the slip and then improves the ductility of W2AlC carbide with high strength. In addition, the calculated Debye temperature follows the order of Cr2AlC > Mo2AlC ≈ W2AlC. Therefore, we believe that W2AlC carbide with (W–C)–Al-(W–C) layered structure can optimize the balance between the strength and ductility of this M2AlC MAX phase.

Bond strength characteristics of masonry using hemp fibre and chicken mesh reinforced mortar

The bonding between the masonry unit and mortar plays very important role in strength of masonry. To improve the bond strength, we need to concentrate on the mortar properties. The present study focusses on the bond strength of masonry by adding reinforcement for the mortar. The hemp fibre and chicken mesh are used as a reinforcement for the mortar. For the test masonry triplets are used with mortar of proportion 1:4. The optimum dosage for hemp fibre is found to be 2% and chicken mesh is added along with mortar joints. The bond strength was tested in universal testing machine and the results have compared each other. From the study it was found that, the bond strength of hemp fibre reinforced triplets is found to be 27% higher than the chicken mesh reinforcement and 73% higher than the unreinforced mortar masonry.

Existing form of Sc in metal-inert gas welded Al-0.60Mg-0.75Si alloy and its role in welding strength

The existing form of Sc in Si-containing 6xxx-series Al alloys and its role in strength has always been controversial. In this study, isothermal section phase diagram of the Al-0.60 wt%Mg-Si-Sc system at 350 °C was calculated by CALPHAD method and Pandat software, and the results show that Sc exists in Al3Sc or V (AlSc2Si2) phases, depending on the contents of Si and Sc. Subsequently, we designed a Al-0.60 Mg-0.75Si-0.05Sc (wt%) Melt Inert Gas (MIG) welded alloy, and investigated its microstructure and mechanical property by tensile tests and electron microscopy. HRTEM and STEM-EDS results show that, Sc exists in the form of core(Sc)-shell (Si) structured (Al, Si)3Sc transition phases with the size range of 60–80 nm in the fractured zone (heat affected zone, HAZ) of the welded joints, deriving from equilibrium phase diagram, V (AlSc2Si2) theoretically. The HAZ of the Al-Mg-Si-Sc joint consists of partly recrystallized grains and strong rolling texture, different from the completely recrystallized and coarsened grains in the Al-Mg-Si joint. In addition, the (Al, Si)3Sc phases increase the density of β'′ aging strengthening phases and prevent them from coarsening under welding heat cycle. The above positive effects of (Al, Si)3Sc particles increase the yield strength, ultimate tensile strength and elongation of Al-Mg-Si welded joints by 31 MPa (20.6%), 41 MPa (21.2%) and 0.8% (12.9%), respectively.

Application of dislocation-based constitutive model into research of dynamic mechanical behavior under shock loading

To understand the plastic deformation mechanism of an FCC metal (pure aluminum) under shock loading and describe its dynamic mechanical behavior accurately, a multiscale constitutive model based on the dislocation substructure is developed, which comprehensively considers the controlling mechanisms of dislocation motion and dislocation evolution. Then, the model is extended to the loading of strong shock waves by incorporating the homogeneous nucleated dislocation within the constitutive framework. The model parameters are successfully determined by the normal plate impact experiments with different thicknesses of specimens. Additionally, shock front perturbation decay experiments are performed using a line velocity interferometer system for any reflector, where the modulated surface of the specimen is subjected to a laser-driven loading. Then, the model is applied to reproduce the perturbation decay of shock fronts in experiments. During the post-process of simulated results, the method based on the pressure gradient is used to determine the amplitude and the location of distributed shock fronts. The extended model shows promise as an effective method to figure out the role of strength (shear response) on the evolution of perturbation amplitude.

Individual- and Peer-Level Risk and Protective Factors for Gun Carriage Among Adolescents Living in Low-Income Urban Communities.

Carrying a handgun is an established risk factor for firearm violence, with detrimental and too often irreversible consequences for adolescents including injury and mortality. Although researchers identified a number of risk factors for adolescent handgun carriage, little is known regarding the role of strengths or developmental assets in buffering against risk. The goal of this study was to identify both risk and protective factors for handgun carriage among a predominantly African American (88%) community-based sample of adolescents (Mage = 14.3) who resided in urban communities with high rates of poverty and exposure to violence. Consistent with prior work, we found that adolescents with access to a handgun or with friends who had carried a handgun had higher odds of carrying a handgun themselves in the past 3 months. Handgun access, friends' handgun carriage, and beliefs supporting reactive aggression were identified as risk factors for handgun carriage. Although personal and social assets and positive outlook moderated these relations, the direction was contrary to our hypotheses. We believe that these findings are in part due to structural inequities and social norms impacting adolescents in urban communities characterized by concentrated poverty and high rates of violence. Our findings highlight the value of moving beyond a deficit-oriented framework to gain a more nuanced understanding of the dynamics among both positive and negative factors that alter risk for handgun carriage among African American youth living in low-income urban areas.

Twinning and dynamic recrystallization behaviors during inchoate deformation of pre-twinned AZ31 Mg alloy sheet at elevated temperatures

To investigate the interrelation of dynamic recrystallization and detwinning behaviors, especially during the inchoate deformation stage at elevated temperatures, a commercial rolled AZ31 Mg alloy sheet is pre-twinned along the transverse direction to introduce {10−12} tensile twins, then the uniaxial stretch deformation is conducted. Results reveal that the detwinning dominates the microstructure evolution at room temperature, 100 °C, and 150 °C, while the dynamic recrystallization participates at temperatures of 200 °C and 250 °C. Further, the continuous dynamic recrystallization and detwinning accommodate the strain at 200 °C, while the discontinuous dynamic recrystallization suppresses the detwinning and predominates the deformation at 250 °C. Under different deformation temperatures, the interaction of dynamic recrystallization and detwinning exhibits different influences on the microstructure. Non-basal slips are activated at elevated temperatures, which affects the dynamic recrystallization behaviors and accommodates deformation strain. The texture evolution is closely related to the microstructure evolution mechanisms. The detwinning plays a hardening role in strength while dynamic recrystallization has a softening influence, the eventual effect on strength depends on the temperature.

Unraveling dislocation-type evolution dominated strain hardening in laminated Ti/Nb composites

Dislocation behavior in laminated metallic composites (LMCs) plays a pivotal role in strength and ductility of bulk materials. Here, we studied evolutions of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) as well as their effects on strain hardening in the uniaxially deformed Ti/Nb LMCs fabricated by accumulative roll bonding plus the subsequent annealing. By combining in-situ neutron diffraction and ex-situ electron backscattered diffraction (EBSD) techniques, for the first time, we quantitatively reveal that dislocation evolutions in the laminates are independent of initial layer thickness within the micron scale. As the applied strain reaches the uniform elongation stage, GND density in Ti increases remarkably by an order of magnitude in all laminates, while that in Nb almost remains unchanged. Besides, the total dislocation density in Ti develops rapidly with deformation, whereas the SSD density does not increase monotonically. In Nb, both total dislocation density and SSD density increase significantly below 0.02 true strain, and gradually saturate in the late stage of strain hardening. During the whole plastic deformation, Nb bears more stress and dominates the global hardening because of the significant development of SSDs in this metal. Importantly, the strengthening induced by heterophase interfaces is more significant in the softer Ti in which GNDs are extensively activated, and SSDs only marginally contribute to the heterophase interface strengthening. These findings provide insights into the exploration of deformation mechanisms in materials with laminated and gradient structures, and also guide the development of LMCs with advanced mechanical properties.

The Role of Strength on Punch Impact Force in Boxing.

Beattie, K and Ruddock, AD. The role of strength on punch impact force in boxing. J Strength Cond Res 36(10): 2957-2969, 2022-The ability to punch with a high impact force is beneficial to boxers as there is an increased likelihood of success. Punch impact force differentiates between performance level, weight class, gender, and punch type in competitive boxers. Although technique is likely to play a major role in punch impact force, the capabilities of the neuromuscular system may also be a limiting factor. This review examines the role of strength on punch impact force in amateur and professional boxers. The maximal strength qualities of the lower body, as well as explosive strength qualities of both the upper and lower body, are largely associated with punch impact force in elite amateur boxers. Specifically, elite amateur boxers who punch with "high" impact forces have greater levels of lower-body maximal strength and explosive strength when compared with elite amateurs who punch with "low" impact forces. However, the maximal strength capabilities of the upper body are not associated with punch impact force and does not differentiate between elite boxers who punch with "high" and "low" impact forces. Therefore, based off the present evidence, this review recommends that for boxers who aim to develop their punch impact force, it may be advantageous to emphasize both maximal and explosive strength development of the legs, with only an explosive strength focus in the upper body. However, it is important to highlight that, to date, there are a lack of experimental studies in both elite amateur and professional boxing. Furthermore, there is a dearth of research in female boxing. Future experimental studies are needed to infer causality regarding the role that strength training has on punch impact force in both elite amateur and professional boxers.

Influence of Water Content on the Mechanical Characteristics of Mudstone with High Smectite Content

Water content plays an important role in strength of mudstone; many works pay more attention to the strength of dry and saturated rocks. In this study, the water absorption characteristics of mudstone were obtained by a computer-automated WA (water absorption) equipment system experiments. The complete stress–strain curves and UCS (unconfined compress strength) and E (Young’s modulus) of mudstone samples under different water contents were achieved by using the WEP-600 microcomputer-control screen universal testing machine. SEM (scanning electron microscope) test were carried out to study the microstructure characteristics of mudstone samples under different water contents. The results showed that the water absorption process of mudstone consists of three stages. The UCS and E of the mudstone samples markedly decrease with water content increasing. Based on the experimental results and analysis, a porous medium mechanical model of the mudstone was established and a deeper understanding of water-induced strength damage mechanism of the mudstone was achieved.

Establishing Reference Values for Isometric Knee Extension and Flexion Strength.

Single-joint isometric and isokinetic knee strength assessment plays an important role in strength and conditioning, physical therapy, and rehabilitation. The literature, however, lacks absolute reference values. We systematically reviewed the available studies that assessed isometric knee strength. Two scientific databases (PubMed and PEDro) were searched for the papers that are published from the inception of the field to the end of 2019. We included studies that involved participants of both genders and different age groups, regardless of the study design, that involved isometric knee extension and/or flexion measurement. The extracted data were converted to body-mass-normalized values. Moreover, the data were grouped according to the knee angle condition (extended, mid-range, and flexed). A meta-analysis was performed on 13,893 participants from 411 studies. In adult healthy males, the pooled 95% confidence intervals (CI) for knee extension were 1.34–2.23Nm/kg for extended knee angle, 2.92–3.45Nm/kg for mid-range knee angle, and 2.50–3.06Nm/kg for flexed knee angle, while the CIs for flexion were 0.85–1.20, 1.15–1.62, and 0.96–1.54Nm/kg, respectively. Adult females consistently showed lower strength than adult male subgroups (e.g., the CIs for knee extension were 1.01–1.50, 2.08–2.74, and 2.04–2.71Nm/kg for extended, mid-range, and flexed knee angle condition). Older adults consistently showed lower values than adults (e.g., pooled CIs for mid-range knee angle were 1.74–2.16Nm/kg (male) and 1.40–1.64Nm/kg (female) for extension, and 0.69–0.89Nm/kg (male) and 0.46–0.81Nm/kg (female) for flexion). Reliable normative for athletes could not be calculated due to limited number of studies for individual sports.

Promoting Rehabilitation Among Youth on Probation: An Examination of Strengths as Specific Responsivity Factors

Despite calls for strength-focused approaches in juvenile justice, there is little research on the role of strengths in probation case management. This is one of the first studies to examine whether strengths function as specific responsivity factors as proposed by the risk–need–responsivity model, through mediating and moderating effects, and findings lend preliminary support to this conceptualization. In a sample of 261 justice-involved youth, the relationship between strengths and recidivism was found to be partially mediated by the service-to-needs match rate, even while controlling for risk—suggesting that strengths have an important indirect effect on recidivism through their impact on youth’s engagement in and completion of services. Strengths, however, did not moderate the relationship between service-to-needs match and reoffending, suggesting that appropriately matched services are essential irrespective of a youth’s strength profile. Research corroborating these findings and examining the feasibility of front-line use of strengths information is warranted.

Exploring the Decision Making Processes of Early Career Strength and Conditioning Coaches

The role of Strength and Conditioning coaches within sporting environments is growing in importance and more attention is being directed towards acknowledging the characteristics and decision making processes of these coaches. To date, most of the research has been with experienced coaches thus created a need to better understand those coaches at the early stages of their career. The present study utilised Applied Cognitive Task Analysis to elicit knowledge from eight strength and conditioning coaches with less than three years full time experience. Methods applied identified that less experienced strength and conditioning coaches operate in predominately stable conditions and feel comfortable delivering within this stability. Interviews revealed early career coaches to prioritise movement qualities and rely on previously acquired theoretical knowledge to make predetermined decisions on training content and responses within environments. A final theme generated demonstrated that connections with athletes were important for coaches to feel confident within their role. Implications for future coach development materials exploring the use of metacognition and its associated components of planning, monitoring and evaluation discussed.

The Role of Strength and Conditioning in the Prevention and Treatment of Chronic Lateral Ankle Instability

ABSTRACT Lateral ankle sprains are one of the most common injuries sustained during sport or physical activity. Up to 40% of individuals can develop chronic lateral ankle instability (CLAI) after a lateral ankle sprain. CLAI occurs when functional or mechanical insufficiencies of the lateral ankle ligamentous complex persist. The purpose of this article is to identify characteristics of CLAI and describe strength and conditioning strategies that can be used to treat lateral ankle ligamentous injuries, preventing them from progressing on to CLAI (See Video, Supplemental Digital Content 1, http://links.lww.com/SCJ/A306).

Experimental study on improvement design of loess curing in engineering environment

This paper investigated the characteristics of improved loess curing in engineering environment. Loess was divided into silt and silty clay, and lime and lime-fly ash were selected as admixture materials. Direct shear tests and permeability tests were performed to research the rules in strength and permeability. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were performed to analyze the improved mechanism. The conclusions are as follows: (1) compared with results curing in laboratory conditions, the fast change periods of strength and permeability starts later and continues longer time for each improved type when curing in engineering environment. For fast change periods of strength, the remolded compacted loess and 2:8 lime-treated loess are between 14~28 days, 3:7 in 14~90 days, and lime-fly ash-treated loess in 28~180 days. As far as permeability is concerned, the permeability coefficient of lime-treated loess and lime-fly ash-treated loess reaches 10−7cm/s in 90 days and 180 days, respectively. (2) Over the long term, the improvement effect still occurs at a slow rate. From 180 to 1090 days, the strength of lime-treated loess and lime-fly ash-treated loess increased by 13.2~16.5%, and their permeability coefficients decreased by 4~7.7%. (3) The properties of untreated loess have a significant role in strength and permeability, and silt and silty clay own different effect ways. (4) Curing conditions and untreated loess properties results to differences of improved loess in age standard and improvement effect, these effects should be considered in engineering projects.

The effect of water cement ratio on the characteristics of multi-walled carbon nanotube reinforced concrete

Water Cement ratio play vital role in strength, durability and serviceability of concrete. In this study effect of water-cement ratio on the strength of multi walled carbon nano tube reinforced concrete is analyzed. Five concrete mixtures at different water-cement ratio (W/C) with and without carbon nano tubes (CNTs) were prepared. W/C of 0.40, 0.45, 0.48, 0.50 and 0.55 were used while quantity of carbon nano tube (CNT) was fixed at 1% by weight of cement (wbc). The workability of carbon nanotube reinforced concrete (CNTC) by was reduced by 39.57% while W/C = 0.48 was found ideal for slump as well as strength. At this W/C compressive strength for CNTC increased by 7.14%.

The unseen evidence of Reduced Ionicity: The elephant in (the) room temperature ionic liquids

The unambiguous quantification of the proton transfer in Protic Ionic Liquids (PILs) and its differentiation from the concept of ionicity are still unsolved questions. Albeit researchers awfully quickly treat them as synonyms, the two concepts are intrinsically different and imply a dramatic modification in the expected chemical and physical properties of a PIL. Some attempts have been made to shed light on this discrimination, but single-technique-based approaches fail in giving a clear answer. Aiming at definitively figuring out the differentiation between proton transfer and ionicity, we performed a multi-technique analysis (NMR, Raman, IR, thermal and electrochemical analyses, among others). Indeed, thermal and spectroscopic analyses are employed to determine the acid strength's role in ions' complete formation. To overcome the ambiguity between ionicity and formation degree, we introduce a new paradigm where Reduced Ionicity accounts for both the quantities mentioned above. The reduced ionicity directly affects the thermal stability, the phase behavior, and the spectroscopic observations, resulting in particular features in NMR and vibrational spectra. The combination of physical-chemical analyses and Pulsed-Gradient Spin-Echo (PGSE) NMR allows determining the reduced ionicity (and not the ionicity, as reported so far) of the investigated systems. In this context, being the proton transfer not quantitatively accessible directly, the reduced ionicity of a reference series of triethylamine-based PILs is investigated through transport properties as a function of temperature. Our findings point towards a substantial dependence of the reduced ionicity by the acid strength and the anion's coordination power. Furthermore, some interesting insights about the proton transfer are obtained, combining all the findings collected.

Cyclic performance of RC beam-column joints enhanced with superelastic SMA rebars

Connections play a significant role in strength of structures against earthquake-induced loads. According to the postseismic reports, connection failure is a cause of overall failure in reinforced concrete (RC) structures. Connection failure results in a sudden increase in inter-story drift, followed by early and progressive failure across the entire structure. This article investigated the cyclic performance and behavioral improvement of shape-memory alloy-based connections (SMA-based connections). The novelty of the present work is focused on the effect of shape memory alloy bars is damage reduction, strain recoverability, and cracking distribution of the stated material in RC moment frames under seismic loads using 3D nonlinear static analyses. The present numerical study was verified using two experimental connections. Then, the performance of connections was studied using 14 models with different reinforcement details on a scale of 3:4. The response parameters under study included moment-rotation, secant stiffness, energy dissipation, strain of bar, and moment-curvature of the connection. The connections were simulated using LS-DYNA environment. The models with longitudinal SMA-based bars, as the main bars, could eliminate residual plastic rotations and thus reduce the demand for post-earthquake structural repairs. The flag-shaped stress-strain curve of SMA-based materials resulted in a very slight residual drift in such connections.

Investigation of Torsion behavior of high strength short fiber reinforced concrete deep beams with openings

This study aims is to investigating the structural capacity of fibbers reinforced deep beams with opening under pure torsion. The deep beams were made of high strength concrete. The openings were made in the web with different shapes (circular and square), sizes and located at the mid span. Seventeen deep beam specimens were casted and they experimentally investigated throughout this study. The constants in this study are beam dimensions and compressive strength for concrete. The effects of the shape, size and locations of opening on the torsional behaviour of deep beams under torsional loading are studied in the paper. The results showed the square opening is weakest due to the concentration effect which increases the stresses and the opening size participate main role in strength of deep without steel fiber. Also, the steel fibre in which the presence of steel fiber causes increasing in the torsion strength about (30-32) of tested specimens.

Starting strong: Dietary, behavioral, and environmental factors that promote "strength" from conception to age 2 years.

Beginning with conception and continuing through childhood and adolescence, the word "strength" connotes the totality of optimal early bone and tissue growth; neural wiring of the brain; and acquisition of fine motor, gross motor, language, and socioemotional skills. The robustness of each of these attributes depend on 3 critical epigenetic (external) factors: the quality of nutrition; positive adult nurturing; and experiences acquired within a stimulating, safe environment that affords free exploration. This review highlights the relationship between the epigenetic factors in the period of conception to age 2 years and a child's future health, cognitive capacity, and social aptitude, which collectively comprise their "strength". This paper was presented as part of the 2018 Strength Summit conference entitled, The Role of Strength in Optimal Health and Well-being. Novelty Strength in infants signifies the totality of optimal early growth and neural wiring of the brain. Strength at this life stage also includes the acquisition of motor, language, and socioemotional skills. Three epigenetic factors are critical during birth to 24 months: nutrition, nurturing, and free exploration.