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Copyright of Journal of Ceramics / Taoci Xuebao is the property of Journal of Ceramics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hybrid composites combining carbon and glass fibers are increasingly studied for their potential to enhance mechanical properties and cost efficiency. Understanding how different hybrid structures influence these properties is critical for optimizing material design and application. In this paper, the mechanical properties of carbon/glass (C/G) interlayer and intralayer hybrid composites, including tensile, compressive, and flexural properties, were tested, and the cost performances of hybrid composites were analyzed to assess the economic feasibility of different stacking configurations. It was revealed that the specific tensile, compressive, and flexural modulus/cost and strength/cost ratios of interlayer and intralayer hybrid composites decreased with increasing carbon fiber content, indicating that adding carbon fiber reduced cost performance. With the combined hybrid ratio and the interlayer structure with glass fiber sandwiching carbon fiber, the tensile and compressive properties were the most cost-effective. When the dispersion degree of the intralayer hybrid structure was 0, the tensile and compressive properties were the most cost-effective. Specifically, for intralayer hybrid composites with a dispersion degree of 0 and C:G = 1:4, the specific tensile strength/cost ratio was 6.7 × 104 N·m/USD, and the specific compressive modulus and strength/cost ratio was 3.8 × 106 N·m/USD and 4.7 × 103 N·m/USD, respectively. However, the flexural performance/cost ratio was found to be opposite to the tensile and compressive results. When carbon fiber was distributed in the bottom layer or used to sandwich the glass fiber, the flexural performance/cost ratio of interlayer hybrid composites was nearly as good as that of glass fiber. Moreover, by considering the working condition of composites, the cost performance of mechanical properties can be optimized and improved through careful design of hybrid ratios and stacking structures. [ABSTRACT FROM AUTHOR]

The purpose of the study was to evaluate selected mechanical properties and structural characteristics of samples manufactured using composite filament fabrication (CFF) technology from Onyx material, whichwas filled with continuous glass fiber. Selected mechanical properties were correlated with the density of the resulting composite to determine the specific strength of the fabricated parts. The test specimens were manufactured on a Mark Two Enterprise machine (Markforged, USA) using composite filament fabrication (CFF) technology. The material used was polyamide 6.6 with a 20% short carbon fiber content with the trade name Onyx. Continuous glass fiber was used to reinforce the fabrication. The density of the manufactured samples was determined using a hydrostatic method. Methanol was used as the liquid. By determining the density of the samples, it was possible to estimate through appropriate calculations what specific strength and specific modulus the obtained composites would have. Determination of tensile and flexural strengths was carried out in accordance with ISO 527-1:2012 and ISO 178:2003. Determination of the impact tensile strength of the samples was carried out in accordance with ISO 8256, the beams were tested using the A method. Due to the high impact tensile strength, two 1 mm notches with an angle of 45°were made on the specimens. The image of the sample structure obtained by the CFF method was recorded using a CT scanner. A thermogravimetric test (TG) of the Onyx matrix material was carried out. The samples were tested approximately 72 hours after fabrication. Filling the samples with continuous glass fiber above 50% leads to a slight increase in impact resistance. The density of the composite increased by only 16% relative to the reference samples, resulting in a 389% increase in the maximum average flexural strength. Despite significant discontinuities in the structure of the produced composite, it was possible to record an increase in tensile strength and Young's modulus by 606% and 370%, respectively. [ABSTRACT FROM AUTHOR]

Green and renewable materials are becoming promising worldwide. Here, we compared morphological and mechanical strength characteristics of natural plant-based bast fibers (flax, hemp and nettle) with those of synthesized fibers (glass, basalt, carbon, polyacrylonitrile (PAN), polycaproamide (PCA) and viscose). The industrial bast fibers from hemp and nettle were extracted by chemical treatment with a sodium carbonate solution. The natural fibers were comparable in size to the synthetic ones. The PCA fibers had the largest diameter of 23–28 µm. The carbon monofiber had the lowest diameter of 7–8 µm. The dimension of the natural elementary fibers was 10–25 µm. The natural fibers had a better interfacial bonding to an epoxy matrix than PCA. Moreover, the specific strength of the unimpregnated and epoxy-impregnated fibers was determined. The natural fibers were superior in strength performance to some of synthetic fibers (viscose), while the specific strength of the impregnated flax fiber was commensurate with that of the impregnated PAN and PCA fibers. The specific strength of the flax and hemp fibers once impregnated with the matrix increased four- and twofold, respectively. The impregnated flax fibers exhibited the best mechanical strength behavior among the hemp and nettle bast fibers. The natural fibers are biodegradable, have a low density, and are more eco-benign than the mineral fibers. The selected natural fibers can be used to fabricate composites therefrom. [ABSTRACT FROM AUTHOR]

This research used fly ash and slag to create geopolymer foam concrete. They were activated with an alkali, resulting in a chemical reaction that produced a gel that strengthened the concrete's structural integrity. The experimental approach involved varying the fly ash content in the precursors at incremental percentages (10%, 30%, 50%, 70% and 90%) and subjecting the fly ash to mechanical activation through a planetary ball mill at distinct rotational speeds (380, 400, 420 and 440 rpm). The investigation discerned that the fly ash content and particle structure exert a discernible influence on macroscopic properties, including flowability, air generation height, compressive strength, dry density and microstructural characteristics such as pore distribution and hydration product arrangement in the geopolymer foam concrete. Employing analytical techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), it was deduced that diminishing the fly ash content correlates with an enhancement in compressive strength. Furthermore, the specific strength of the geopolymer foam concrete reached a peak of 0.041 when the activated fly ash in the planetary ball mill rotated at 420 rpm, manifesting a lightweight and high-strength outcome. [ABSTRACT FROM AUTHOR]

Lightweight alloys are known to improve the fuel efficiency of the structural components due to high strength-to-weight ratio, however, they lack formability at room temperature. This major limitation of poor formability is most of the time overcome by post-fabrication processing and treatments thereby increasing their cost exponentially. We present a novel Ti50V16Zr16Nb10Al5Mo3 (all in at. %) complex concentrated alloy (Ti-CCA) designed based on the combination of valence electron concentration theory and the high entropy approach. The optimal selection of constituent elements has led to a density of 5.63 gm/cc for Ti-CCA after suction casting (SC). SC Ti-CCA displayed exceptional room temperature strength (UTS ∼ 1.25 GPa) and ductility (ε ∼ 35 %) with a yield strength (YS) of ∼ 1.1 GPa (Specific YS = 191 MPa/gm/cc) without any post-processing treatments. The exceptional YS in Ti-CCA is attributed to hetero grain size microstructure, whereas enormous strength-ductility synergy is due to the concurrent occurrence of slip and deformation band formation in the early stages of deformation followed by prolonged necking event due to delayed void nucleation and growth. The proposed philosophy of Ti-CCA design overcomes the conventional notion of strength-ductility trade-off in such alloy systems by retaining their inherent characteristics.

New types of hybrid aluminum joints: Al-acrylonitrile butadiene styrene (ABS) carbon fiber reinforced thermoplastic polymer (CFRTP) designated Al/Ni-CFP/ABS, and Al-18-8 Stainless steel, Al/Ni-CFP/18-8, by Ni-plated carbon fiber plug (Ni-CFP) insert not before seen in the literature have been fabricated. The goal is to take advantage of extremely high ~6 mm CF surface area for high adhesion, to enhance the safety level of aircraft and other parts. This is without fasteners, chemical treatment, or glue. First, the CFP is plated with Ni. Second, the higher melting point half-length is spot welded to the CFP; and third, the remaining half-length is fabricated. The ultimate tensile strength (UTS) of Al/Ni-CFP/ABS was raised 15 times over that of Al/ABS. Normalized cUTS according to CFP cross-section by Rule of Mixtures for cAl/Ni-CFP/18-8 was raised over that of cAl/Ni-CFP/18-8 from 140 to 360 MPa. Resistance energy to tensile deformation, UT, was raised 12 times from Al/ABS to Al/Ni-CFP/ABS, and 6 times from Al/CFP/18-8 to Al/Ni-CFP/18-8. Spot welding allows rapid melting followed by rapid solidification for amorphous metal structures minimizing grain boundaries. The Ni-coating lowers or counters the effects of brittle Al4C3 and FexC formation at the interface and prevents damage by impingement to CFs, allowing joints to take on more of the load. [ABSTRACT FROM AUTHOR]

This research used fly ash and slag to create geopolymer foam concrete. They were activated with an alkali, resulting in a chemical reaction that produced a gel that strengthened the concrete’s structural integrity. The experimental approach involved varying the fly ash content in the precursors at incremental percentages (10%, 30%, 50%, 70% and 90%) and subjecting the fly ash to mechanical activation through a planetary ball mill at distinct rotational speeds (380, 400, 420 and 440 rpm). The investigation discerned that the fly ash content and particle structure exert a discernible influence on macroscopic properties, including flowability, air generation height, compressive strength, dry density and microstructural characteristics such as pore distribution and hydration product arrangement in the geopolymer foam concrete. Employing analytical techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), it was deduced that diminishing the fly ash content correlates with an enhancement in compressive strength. Furthermore, the specific strength of the geopolymer foam concrete reached a peak of 0.041 when the activated fly ash in the planetary ball mill rotated at 420 rpm, manifesting a lightweight and high-strength outcome.

C/SiC aerogels with both ultra-low thermal conductivity and extremely high strength were fabricated by freeze casting. SiC junctions originated from pyrolysis of polycarbosilane (PCS) were formed between carbon nanofibers (C f) to enhance the strength of aerogels. The effects of PCS content and total solid content on the phase composition, pore structure, thermal conductivity and compressive property were studied. The fabricated aerogels possess hierarchical pore structure. In the micro-scale, it contains circular pores with size of about 15 µm, while it is mesoporous and macroporous in the nano-scale. Both thermal conductivity and compressive strength increase with the increase in PCS content. Through tailoring PCS content and total solid content, C f /SiC aerogels with porosity of 99.5%, thermal conductivity of 33 mW·m−1·K−1 and compressive strength of 7.14 MPa can be obtained. The specific strength of the fabricated C f /SiC aerogels is up to 467.6 MPa/(g/cm3), which is the highest value for ceramic aerogels. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, the development of concrete has been toward to the direction of lightweight and high strengthening. This study developed a kind of lightweight ultra-high strength concrete(L-UHSC) through the comprehensive design method, which had an apparent density rang of 1995 kg/m3-2114 kg/m3 and a compressive strength of 102.4–114.5 MPa. The specific strength of the designed L-UHSC is more than 50 MPa/(t/m3), which is higher than ordinary structural lightweight aggregate concrete (LAC). Additionally, the roles of high-performance paste, lightweight aggregate (LWA) and steel fiber in L-UHSC were revealed through scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and strength test. The findings revealed that SF content, rather than the binder-sand ratio and aggregate ratio, has a greater impact on density and strength, and the aggregate ratio having the least effect. As steel fiber content increases from 0.5 % to 2.0 %, compressive strength, flexural strength and splitting tensile strength of LAC increase by 44.3 %, 120 % and 151 %, respectively, which is higher than that of ultra-high performance (UHPC). The micromorphology and pore structure research suggested that the high-performance paste plays a keystone role in achieving the ultra-high strength, and LWAs mainly affected strength through improving pore structure. In addition, small size pre-wetted LWA is more conducive to concrete strength. Our preliminary results provide a reference for the research and development of lightweight ultra-high strength cement composites.

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the increasing demand for high-specific-strength materials for high-temperature applications, particularly in the aerospace field, novel (TiVCrZr)100−xWx (x = 5, 10, 15 and 20) refractory high-entropy alloys (RHEAs) were developed. The phase formation, microstructure, and mechanical properties were studied. The (TiVCrZr)100−xWx RHEAs exhibit a relatively high specific strength and low density compared with the W-containing RHEAs and most of the W-free RHEAs. In (TiVCrZr)100−xWx RHEAs, Laves, BCC and Ti-rich phases are formed, where the Laves phase is the major phase, and the volume fraction of the BCC phase increases with increasing W content. (TiVCrZr)100−xWx RHEAs exhibit dendrite structures, where W is enriched in the dendrite region, and increasing W-rich precipitations corresponding to the BCC phase are observed. The improvement of the strength and hardness of RHEAs is mainly attributed to the evolution of the microstructure and corresponding strengthening effect of W. The empirical parameters and calculated phase diagram were investigated, which further explain and verify the formation and variation of phases. The present findings give more insights into the formation of multi phases in (TiVCrZr)100−xWx RHEAs, and explore their application potential in the aerospace industry and nuclear reactors due to their high specific strength and low-activation constituent elements. [ABSTRACT FROM AUTHOR]

Although honeycomb is a kind of lightweight structural material with great potential, its specific strength is not always able to meet the requirements, especially in the weight-sensitive field. Inspired by the bionic idea of cuttlebone, the curved-wall configuration design is proposed to strengthen the buckling impedance of honeycomb, which can effectively prevent the premature occurrence of buckling failure mode induced by thin walls. Compared with the straight-wall honeycomb materials of the same geometric size, the probability of buckling failure in curved-wall honeycomb materials proposed in this paper is reduced by more than 22 %. Moreover, to achieve the preparation of curved-wall configuration, a processing strategy that uses stretching process to prepare ultralight carbon fiber honeycomb (Carbcomb) material is firstly introduced. Compared to the Hexcel Corporation's aluminum honeycomb with a density of 21 kg/m3, for the Carbcomb, the specific compressive strength and specific shear strength along both the L and W directions respectively improved by 57 %, 61 % and 77 %. In addition, the minimum density of fabricated Carbcomb (14.6 kg/m3) is less than that of the Hexcel's products (16 kg/m3), and the research findings fill the gap of the carbon fiber honeycomb material in low density areas (10 ∼ 30 kg/m3). More importantly, this process which does not require much manual operation can effectively avoid the problems of unstable mechanical properties, difficult mass production and high preparation cost of the existing carbon fiber structural parts. This curved-wall configuration design and fabricated approach widens the potential of carbon fiber honeycomb as a structural material, and makes it possible for lower cost and higher efficiency in aerospace and transportation applications. [ABSTRACT FROM AUTHOR]

Advanced aluminum-lithium alloys are the key structural materials urgently needed for the development of light-weighted aircraft in the aerospace field. In this study, we employ a machine learning approach accompanied by domain knowledge to realize the accelerated design of aluminum-lithium alloy with high specific modulus and specific strength by identifying an optimal combination of key features through a three-step feature filtering of datasets containing 145 alloys. The maximum specific modulus in the experimental alloys that screened from the predicted results increases by 4 % compared with the maximum specific modulus in the comparative dataset. The specific modulus of the designed alloy with the best comprehensive performance increased by 12.6 % compared with the widely used 2195-T8 alloy while maintaining a similar specific strength. Machine learning shows appealing feasibility and reliability in the field of materials design.

In this work, Ti/Al and Ti/Ni metal intermetallic laminates (MILs) prepared by diffusion bonding are compared based on the intermetallic phases formed, specific strength and density. The Ti/Al MILs are characterized by the formation of TiAl3 intermetallic compound. Three different intermetallic phases, namely TiNi3, TiNi and Ti2Ni, are formed in the Ti/Ni MILs. The compression behaviour of both the laminates is anisotropic when there is a change in the loading direction and the strength increased with the increase in intermetallic volume fraction. The specific strength varied in accordance with the intermetallic volume fraction ranging from 85 to 220 kN m/kg for Ti/Al MILs and 104 to 223 kN m/kg for Ti/Ni MILs. There is a considerable reduction in the density of both the MILs when the intermetallic volume fraction increased. However, Ti/Al MILs has the lower density values ranging from 3165 to 3618 kg/m3 than Ti/Ni laminates, which has the values from 4922 to 5519 kg/m3.

As one of the most innovative cement‐based materials, the properties of ultra‐high‐performance concrete (UHPC) have been widely investigated. This paper experimentally studies the effect of ceramsite sand on the properties and microstructure of UHPC to develop a new UHPC with low apparent density. The effects of the volume ratio of ceramsite sand and steel fiber content on the properties of UHPC were also studied. Various experiments, including apparent density, compressive and flexural strength, and microstructural properties were conducted on UHPC with different mixing parameters. The results showed that the addition of 18% ceramsite sand effectively improved the mechanical strength, specific strength, and pore structure as well as the interfacial transition zone of UHPC. Steel fiber and ceramsite sand worked together to make up for the lack of lightweight porous aggregate so that even when 100% ceramsite sand was used to prepare UHPC, the compressive strength of concrete could still exceed 100 MPa, and had a lower apparent density than normal UHPC. [ABSTRACT FROM AUTHOR]

Background and Purpose: We followed and documented skeletal muscle adaptations from 4 resistance exercise (RE) prescriptions in older adults over the course of a 2-year, 80-week training study. Methods: Forty-three older men and women—65.2 (3.5) years, 167.2 (7.5) cm, and 72.5 (14.7) kg—completed one of the following RE prescriptions: high-load 2 days per week (HL2D; n = 12), low-load 2 days per week (LL2D; n = 9), high-load 3 days per week (HL3D, n = 12), or low-load 3 days per week (LL3D, n = 10). High-load prescriptions consisted of 3 sets of 8 repetitions with 80% 1-repetition maximum (1-RM) and low-load prescriptions completed 3 sets of 16 repetitions with 40% 1-RM. Each session consisted of 12 exercises targeting major muscle groups and training loads were adjusted every fifth week to maintain progressive overload. Participants completed 40 weeks of supervised training, had a 2-month break, and then resumed another 40 weeks of supervised training. Bone-free lean body mass (BFLBM) and appendicular lean mass (ALM) were assessed via dual-energy x-ray absorptiometry and muscle cross-sectional area (mCSA) of the rectus femoris with diagnostic ultrasound across the intervention. Results and Discussion: Groups responded similarly with significant increases in total strength (54.9%), upper body strength (42.7%), lower body strength (61.5%), and specific strength (50.3%, strength/BFLBM) over 80 weeks (all P <.001). Significant increases for BFLBM (3.0%), ALM (3.5%), and mCSA (48.7%) were also observed (all P ≤.019). The only difference among groups indicated HL3D displaying significantly greater percent increase than LL2D for ALM (P =.043). Conclusions: Resistance exercise performed 2 or 3 days per week with moderate to heavy loads can improve muscle strength and induce small but perhaps clinically significant increases in BFLBM and mCSA in older adults over a 2-year period of supervised training. [ABSTRACT FROM AUTHOR]

[Display omitted] • A next-generation light-weight Ti 50 V 16 Zr 16 Nb 10 Al 5 Mo 3 CCA (Ti-CCA) is designed merging VEC and HEA approach. • The engineered selection of constituent elements not only reduced the cost but also led to a density of 5.63 gm/cc for Ti-CCA. • As-cast Ti-CCA displayed exceptional room temperature strength (UTS ∼ 1.25 GPa) and ductility (ε ∼ 35 %) with a yield strength (YS) of 1.1 GPa. • The exceptional YS is attributed to very fine heterogenous-grained equiaxed microstructure. • Enormous strength-ductility synergy in Ti-CCA is due to the concurrent occurrence of deformation band-induced plasticity and prolonged necking events. Lightweight alloys are known to improve the fuel efficiency of the structural components due to high strength-to-weight ratio, however, they lack formability at room temperature. This major limitation of poor formability is most of the time overcome by post-fabrication processing and treatments thereby increasing their cost exponentially. We present a novel Ti 50 V 16 Zr 16 Nb 10 Al 5 Mo 3 (all in at. %) complex concentrated alloy (Ti-CCA) designed based on the combination of valence electron concentration theory and the high entropy approach. The optimal selection of constituent elements has led to a density of 5.63 gm/cc for Ti-CCA after suction casting (SC). SC Ti-CCA displayed exceptional room temperature strength (UTS ∼ 1.25 GPa) and ductility (ε ∼ 35 %) with a yield strength (YS) of ∼ 1.1 GPa (Specific YS = 191 MPa/gm/cc) without any post-processing treatments. The exceptional YS in Ti-CCA is attributed to hetero grain size microstructure, whereas enormous strength-ductility synergy is due to the concurrent occurrence of slip and deformation band formation in the early stages of deformation followed by prolonged necking event due to delayed void nucleation and growth. The proposed philosophy of Ti-CCA design overcomes the conventional notion of strength-ductility trade-off in such alloy systems by retaining their inherent characteristics. [ABSTRACT FROM AUTHOR]

Abstract Background The improvement in muscle strength generally exceeds the increase in muscle size following strength training in frail elderly, highlighting the complex aetiology of strength deficit in aging. The aim of this study was to investigate the effect of heavy‐load strength training on a broad number of factors related to specific strength in frail elderly. Methods Thirty‐four frail elderly men (n = 18) and women (n = 16) aged 67 to 98 (86 ± 7 years) were randomized to either a group performing strength training twice a week for 10 weeks (ST) or a non‐exercising control group (CON). Knee extensor muscle strength was tested as one‐repetition maximum (1RM) and isometric maximal voluntary contraction (MVC) torque. Muscle activation was assessed by the interpolated twitch technique, and muscle density [mean Hounsfield units (HU)] and intermuscular adipose tissue (IMAT) by computed tomography scans of the quadriceps femoris. Muscle biopsies from the vastus lateralis were obtained to investigate changes in intramyocellular lipids and single‐fibre specific tension. Results In ST, knee extension 1RM and MVC improved by 17 and 7%, respectively. Muscle cross‐sectional area of the quadriceps femoris increased by 7%, accompanied by a 4% increase of muscle density. No changes in IMAT, voluntary activation level, single‐fibre specific tension, or lipid content were observed. Conclusions In contrast to several previous reports, the improvements in isometric muscle strength and muscle area were in good agreement in the present study. The training‐induced increase in muscle density was not due to changes in skeletal muscle lipid content. Instead, the increase in muscle density may reflect increased packing of contractile material or simply an increased ratio of muscle tissue relative to IMAT.

With the increasing demand for high-specific-strength materials for high-temperature applications, particularly in the aerospace field, novel (TiVCrZr)100−xWx (x = 5, 10, 15 and 20) refractory high-entropy alloys (RHEAs) were developed. The phase formation, microstructure, and mechanical properties were studied. The (TiVCrZr)100−xWx RHEAs exhibit a relatively high specific strength and low density compared with the W-containing RHEAs and most of the W-free RHEAs. In (TiVCrZr)100−xWx RHEAs, Laves, BCC and Ti-rich phases are formed, where the Laves phase is the major phase, and the volume fraction of the BCC phase increases with increasing W content. (TiVCrZr)100−xWx RHEAs exhibit dendrite structures, where W is enriched in the dendrite region, and increasing W-rich precipitations corresponding to the BCC phase are observed. The improvement of the strength and hardness of RHEAs is mainly attributed to the evolution of the microstructure and corresponding strengthening effect of W. The empirical parameters and calculated phase diagram were investigated, which further explain and verify the formation and variation of phases. The present findings give more insights into the formation of multi phases in (TiVCrZr)100−xWx RHEAs, and explore their application potential in the aerospace industry and nuclear reactors due to their high specific strength and low-activation constituent elements.

Copyright of Advanced Engineering Science / Gongcheng Kexue Yu Jishu is the property of Advanced Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim in this investigation is focused on the evaluation of two distinctive powder size ratios of pure elements (Al, Si and Cu) powders. Heat treatments (T4 and T6) affecting the mechanical strengths of Al/Si/Cu composites are also investigated. The novelty concerns to pure elements to constituting the composites and no melting or stir casting route are used. It is found that the densifications and tensile strengths are similar when distinct powder size ratios are used. It is also found that T4 and T6 treatments increases and decreases the mechanical strengths, respectively. The Si content indicates a deleterious effect in mechanical behavior. The T6 aging provides θ-Al2Cu incoherent with Al matrix, and the compressive strength is decreased. This suggests that the examined Al/Cu composites (using pure powders) are potential materials considering economical and environmentally friendly aspects. [ABSTRACT FROM AUTHOR]

The utilization of granite sludge offers significant economic and environmental advantages. This study focuses on preparing porous glass-ceramics from Ca(OH) 2 -modified granite sludge through a two-step sintering process comprising dense sintering and high-temperature foaming, with the addition of 1 % SiC powder as a foaming agent. The impact of foaming temperature and Ca(OH) 2 addition on the structure, compressive strength, specific strength, and thermal conductivity of the porous glass-ceramics is examined. Incorporating the Ca(OH) 2 modifier reduces the glass's viscosity and effectively eliminates micropores on the pore walls. The former promotes foaming and increases porosity, while the latter increases the specific strength of porous glass-ceramics. Increasing both the foaming temperature and the Ca(OH) 2 concentration reduces glass viscosity and promotes mineral dissolution, facilitating the foaming process. However, the specific strength of the porous glass-ceramics initially increases before decreasing due to pore coalescence and excessive mineral dissolution. Theoretical evaluations of compressive strength and thermal conductivity indicate that porous glass-ceramics possess a closed-cell pore structure. Porous glass-ceramic made from granite powder containing 3.5 % Ca(OH) 2 and foamed at 1240 °C exhibits an apparent density and porosity of 0.73 g/cm3 and 67.1 %, respectively. The compressive strength and thermal conductivity are 14.2 MPa and 0.422 W/(m·K) respectively, with a peak specific strength of 19.4 kN·m/kg. This innovative process enables the scalable recycling of granite sludge into energy-saving building materials. [Display omitted] • Ca(OH) 2 modifier reduces glass viscosity and eliminates micropores. • The pore glass-ceramics was confirmed to have a closed pore structure. • High specific strength porous glass-ceramics were sintered from granite sludge. • Pore coalescence and excessive mineral dissolution reduce specific strength. [ABSTRACT FROM AUTHOR]

Vertical elevation may be critical for advantage to Special Operation Forces and require strength, power, endurance, and technique. This study sought to (a) study differences in physical capacities of Naval Special Warfare lead climbers from nonlead climbers, (b) compare anthropometries of lead climbers from nonlead climbers, and (c) catalogue the types and weights of the various climbing systems to assess total system weight to the lead climber's body mass. Climbing surveys were collected and retrospective physical capacity data from 15 SEa, Air and Land lead climbers (age: 31.2 ± 5.1 years; height: 181.4 ± 6.4 cm; mass: 89.4 ± 10.0 kg; body fat: 14.1 ± 3.7%) were compared against previously reported data of 305 nonlead climbers (age: 28.8 ±5.2 years; height: 177.6 ± 12.0 cm; mass: 85.8 ±9.7 kg; body fat: 17.3 ±4.7%). Lead climbers had significantly less body fat percentage (p = 0.017). Lead climbers also performed significantly better on the pro-agility test (p = 0.017) and deadlift (p = 0.002). The total mass reported for the climbing equipment for each tactical scenario was up to 4.9 kg for urban climbing, up to 13.7 kg for alpine climbing, and up to 8.0 kg for maritime climbing. With a typical combat load of 21.4 kg, adding an alpine climbing load exceeds one-third of the lead climbers' own body mass. Strength and conditioning programming for this population should take into consideration the total system weight for testing and training purposes and should also consider climbing-specific strength testing and training to optimize climbing capability. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Physical Education Institute / Shanghai Tiyu Xueyuan Xuebao is the property of Shanghai Physical Education Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Myotonic dystrophy (DM1) patients had lower expected strength compared to controls. • Muscle unit dysfunction correlates to percent of expected strength in DM1. • qMRI may be used as a measure to monitor disease severity in patients with DM1. Our aim was to determine isokinetic strength and degeneration of lower extremity muscles in patients with Myotonic Dystrophy (DM1). In 19 patients with DM1 and 19 matched controls, strength measured by isokinetic dynamometry was expressed as percentage of expected strength (ePct), adjusted for age, height, weight and gender. MRI of the hip, thigh and calf muscles were obtained. Fat fraction (FF), mean contractile cross-sectional area (cCSA) and specific strength (Nm/cm2) were calculated. Patients' ankle plantar flexors, knee flexors and extensors had higher FF (Δ: 0.08 – 0.42) and lower cCSA (Δ: 3.2 –17.1 cm2) compared to controls (p ≤ 0.005). EPct (Δ: 19.5 – 41.6%) and specific strength (Δ: 0.27 – 0.96 Nm/cm2) were lower in the majority of patients muscle groups (p˂0.05). Close correlations were found for patients when relating ePct to; FF for plantar flexors (R2=0.742, p <0.001) and knee extensors (R2=0.732, p <0.001), cCSA for plantar flexors (R2=0.696, p <0.001) and knee extensors (R2=0.633, p <0.001), and specific strength for dorsal flexors (ρ=0.855, p = 0.008). In conclusion, patients had weaker lower extremity muscles with higher FF, lower cCSA and specific strength compared to controls. Muscle degeneration determined by quantitative MRI strongly correlated to strength supporting its feasibility to quantify muscle dysfunction in DM1. [ABSTRACT FROM AUTHOR]

The weight lightening of electric vehicles’ power battery box not only improves the vehicles’ mileage but also extends the service life of the power battery, while in practice the design of lightweight shall not sacrifice its strength for safety reason. Herein, three materials including the glass fiber composite, carbon fiber composite, and metal steel are used to develop the same power battery box and their strengths are simulated. The results show that the sheet molding compound (SMC, a kind of glass fiber composite) power battery pack shall be damaged when the loaded extrusion force is increased to 98.2 kN; for the metal power battery pack, a force of 81 kN would make the deformation more than 30%; while for the carbon fiber composite one, it can stand the extrusion test up to 100 kN, and the specific gravity and specific strength are higher than the former two materials under the same design model condition. This study proves the carbon fiber composite has the advantages of high strength and light weight when applied to the power battery box.

The Fused Deposition Modeling (FDM) fabrication is commonly used printing technique, the reasons behind this are low consumable cost, simplicity of workflow and more reliable. The quality of the printed parts depends on various process variables such as part orientation, layer thickness, hotend and bed temperature, fabricating speed, infill pattern and infill density, number of top-bottom solid layers, number of shells etc. Literature suggests that infill density, number of shells and number of top-bottom solid layers are variables that changing the tensile strength under tension of 3D fabricated parts and also have effect on weight of the parts. This study focuses on effect of infill density (ID), number of shells (NS) and top-bottom solid layers (TBSL) on specific strength (strength/weight ratio). Taguchi L18 Orthogonal Array (OA) design is used to perform the experiments. 18 runs with 3 repeated specimens were printed according to the ASTM D638 Type I standard using different printing variables. According to the results, parameters increase of ID, NS and TBSL were seen to effect significant improvement in the specific strength increase. However, between 40-60% ID has negative effect to specific strength while NS and TBSL increase. [ABSTRACT FROM AUTHOR]

Welding of copper and copper alloys through conventional welding processes not only exhibit various difficulties during the joining process but also causes the production of harmful gases, which affect human life. This work deals with the joining of copper-based materials using microwave radiation and brass as a filler material without any harmful gases. The resulted joints are characterized by using metallurgical microscopy. Mechanical characterizations are done through tensile testing, Brinell's hardness testing, corrosion testing, and specific strength testing. The results reveal that the successful joining of copper-based materials is possible by using brass based powder as filler material via microwave radiation. The resulted joints have uniform metallurgical structure and lower defects. It confirms better diffusion between materials at joints. Higher mechanical strength is resulted due to lower processing defects. The results show that the ultimate tensile strength and hardness obtained in this study are higher than the base material. [ABSTRACT FROM AUTHOR]

Background: The improvement in muscle strength generally exceeds the increase in muscle size following strength training in frail elderly, highlighting the complex aetiology of strength deficit in aging. The aim of this study was to investigate the effect of heavy‐load strength training on a broad number of factors related to specific strength in frail elderly. Methods: Thirty‐four frail elderly men (n = 18) and women (n = 16) aged 67 to 98 (86 ± 7 years) were randomized to either a group performing strength training twice a week for 10 weeks (ST) or a non‐exercising control group (CON). Knee extensor muscle strength was tested as one‐repetition maximum (1RM) and isometric maximal voluntary contraction (MVC) torque. Muscle activation was assessed by the interpolated twitch technique, and muscle density [mean Hounsfield units (HU)] and intermuscular adipose tissue (IMAT) by computed tomography scans of the quadriceps femoris. Muscle biopsies from the vastus lateralis were obtained to investigate changes in intramyocellular lipids and single‐fibre specific tension. Results: In ST, knee extension 1RM and MVC improved by 17 and 7%, respectively. Muscle cross‐sectional area of the quadriceps femoris increased by 7%, accompanied by a 4% increase of muscle density. No changes in IMAT, voluntary activation level, single‐fibre specific tension, or lipid content were observed. Conclusions: In contrast to several previous reports, the improvements in isometric muscle strength and muscle area were in good agreement in the present study. The training‐induced increase in muscle density was not due to changes in skeletal muscle lipid content. Instead, the increase in muscle density may reflect increased packing of contractile material or simply an increased ratio of muscle tissue relative to IMAT. [ABSTRACT FROM AUTHOR]

This investigation is focused on the evaluation of the fresh and hardened states of a distinctive and novel self-compacting concrete (SCC) with two distinct nonpozzolanic contents, i.e., gray phyllite (PLT) and marble + granite powders. Although the phyllite is commonly commercialized in SCC preparation, a distinctive mixture using the phyllite and marble + granite contents is used. Marble and granite beneficiation residues (MGBR) come from an ornamental stone industry, and their inappropriate discard drastically damage the environment. To characterize the starting additions and SCC specimens, SEM (scanning electron microscope) and XRD (x-ray diffraction) techniques are used. The resulting mechanical behavior favors the SCC with the MGBR content, which is ∼40% higher than the SCC with the PLT content. Additionally, when the mechanical strength-to-relative cost ratio is determined, the SCC with the MGBR content shows a value between 1.1 and 1.3 times higher than the SCC containing phyllite. This suggests that an economical aspect concatenated with mechanical performance and environmentally friendly aspect is induced. The SCC with the MGBR represents a promising alternative for the traditional self-compacting concrete. [ABSTRACT FROM AUTHOR]

For better utilization of construction & demolotion waste (CDW) together with fly ash, recycled concrete bricks were fabricated by using recycled concrete aggregate, cement and fly ash. The effects of different replacement ratio of cement by fly ash on the apparent density, porosity, compressive strength, flexural strength and specific strength of recycled concrete bricks were researched. The test results showed that especially in the 14-day-old period, the compressive strength, flexural strength and specific strength of recycled concrete bricks were significantly improved at 20% replacement ratio of cement by fly ash, and the mechanical properties of the recycled bricks at the 28-day-old age are also improved, while the apparent density was reduced and the porosity was little increased. [ABSTRACT FROM AUTHOR]

• F25 had a strength of 82 MPa and a density of 1566 kg/m3. • A correlation is identified between the FAC content and the formation of N-A-S-H gel. • The co-existence of CASH/NASH phases is responsible for high strength of the matrix. • Developed composites exhibited a higher merit number than the traditional materials. In the current work, the mechanical and thermal characteristics of environmentally friendly lightweight composites with high specific strength (defined as the ratio of strength to density) and low thermal conductivity are examined. To increase the sustainability of composites, ordinary Portland cement (OPC) was completely replaced with alkali-activated alumino-silicate by-products, including ground granulated blast furnace slag (GGBFS) and silica fume (SF). The micro-sized hollow fly-ash cenospheres (FAC), together with alkali-activated binders (AAB), are used to produce lightweight composites under ambient conditions. The novel composites had 28-day compressive strength ranging from 29.7 to 82.3 MPa, and dry densities ranged from 953 to 1566 kg/m3. The thermal conductivity of the optimal mix was 0.223 W/(m⋅K), which is lower than that of cementitious materials reported in the literature at the same specific strength. Based on the results obtained from the microstructural analysis, the high compressive strength associated with low thermal conductivity of FAC-modified AAB is attributed to (i) the co-existence of C-A-S-H/N-A-S-H phases is beneficial for the formation of a high-strength matrix, (ii) the presence of a strong interface between matrix and FAC, and (iii) the void sizes introduced is controlled below 50,000 nm. [ABSTRACT FROM AUTHOR]