To achieve isotropic strength in GH3536 foil, this study investigated the influence mechanism of initial recrystallization microstructure and texture characteristics of GH3536 superalloy foil with ...different cold-rolled reduction rates (referring to the reduction rate in thickness) on annealing recrystallization microstructure, including secondary recrystallization microstructure, and texture. This was studied by controlling the cold-rolled reduction rate and annealing temperature, in conjunction with microstructure and texture analysis. Meanwhile, this study clarified the dependency of strength performance on recrystallization microstructure and texture. The results of this study indicate that the Coincidence Site Lattice (CSL) grain boundaries and High Energy (HE) grain boundaries did not show significant superiorities, and were not the primary reasons for the formation of Brass ({011} ) and Goss ({011} ) textures, as well as secondary recrystallization. Instead, by controlling the cold-rolled reduction rate, the initial recrystallization stage formed a significant quantity and size superiority of α-fiber texture ({110}∥ND) in each grain size range. This led to preferential growth, and even abnormal growth of Brass and Goss grains in subsequent high-temperature annealing processes. The control of the α-deformation fiber texture was identified as the driving factor behind the formation of the initial recrystallization texture due to the cold rolling reduction rate. Cold-rolled processes with a deformation amount greater than 40 % yielded a quantity superiority of α-fiber texture shear bands and an appropriate stored energy advantage. This facilitated the nucleation and effective growth of more α grains, while suppressing the random growth of grains with γ-fiber texture ({111}∥ND). Ultimately, a quantity and size superiority was achieved in the initial recrystallization stage. The tensile strength of GH3536 foil was controlled by grain size and texture. By controlling the deformation amount to approximately 30 %, GH3536 foil was successfully produced with no pronounced orientation texture and isotropic strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK, ZAGLJ
Porous media are used widely in technological (e.g., transpiration cooling and heat sinks for electronic devices), and biological (e.g., bone tissue) applications. The requirement for performance ...optimization demands a transition from passive selection to actively designing the topology of porous media. Triply periodic minimal surface (TPMS) structures provided unique opportunities for customizing porous media. Further research is required regarding the quick topology customization, heat transfer correlation, and strength performance of TPMS porous structures. In this study, the correlations among the feature parameters in the TPMS equations in terms of the porosity (uniform and smooth graded), pore density, and equivalent pore diameter were also determined, thereby providing a rapid method for customizing the topology of TPMS porous structures. The correlations of flow resistance and heat transfer coefficient were determined in four TPMS porous structures (W type, P type, D type, and G type) by considering the Reynolds number (Reh = 10–129) and porosity (ɛ = 0.2–0.8). The strengths of TPMS-based porous structures were compared in experimental tests by combining with theoretical analysis. The results obtained in the present study provide valuable guidance for customizing the topology of TPMS porous media and predicting their performance in terms of flow resistance, and heat transfer, and strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The ideal mixing ratio of metakaolin-based geopolymer binder was studied.•The cost-optimal mixing ratio of the geopolymer binder in clay soil was investigated.•The strength performance improvement ...of the geopolymer-improved soil was analyzed.•The stabilization effect of the geopolymer binder on clay soil was discussed.
Geopolymer binder is a kind of green cementitious material with fast hardening, high strength, low shrinkage, and acid-alkali corrosion resistance. It is very beneficial to ensure the firmness, stability, and durability of subgrade structure in cold regions. In this study, the unconfined compression strength test of the clay soil improved by metakaolin-based geopolymer binder was carried out. The material ratio of the metakaolin-based geopolymer binder was analyzed, the optimal mixing ratio of the metakaolin-based geopolymer binder in the clay soil was investigated, and the impacts of metakaolin and alkali-activator on the mechanical properties of the geopolymer-improved soil were discussed. Experimental results indicate that the unconfined compression strength of the geopolymer-improved soil increases first and then decreases with the contents of metakaolin and alkali-activator (a mixture of unslaked lime (CaO) and sodium bicarbonate (NaHCO3) with the mass ratio of 1:1). The ideal mixing ratio of metakaolin and alkali-activator in the geopolymer binder is about 2:1, and the cost-optimal mixing ratio of the geopolymer binder in the clay soil is about 12%. By comparing with pure clay soil, lime soil, and ordinary Portland cement soil, the strength performance and stabilization effect of the geopolymer-improved soil were further studied through unconfined compression strength test, direct shear test, and Brazilian split-cylinder test. Outcomes show that the unconfined compression strength, shear strength, and Brazilian splitting strength of the geopolymer-improved soil have good advantages over the other three kinds of soils. The microstructure analysis by SEM with EDS illustrates that the agglomeration and stabilization effects of the geopolymer-improved soil, ordinary Portland cement soil, lime soil, and pure clay soil are weakened in turn, and the polymerization of the geopolymer binders can be in progress in the alkali-activated environment formed from the hydration of CaO and its reaction with NaHCO3. The failure of the geopolymer-improved soil with the increasing contents of metakaolin and alkali-activator shows that there is a tendency from plastic shear failure to brittle split failure. The results of this study can provide a parameter basis for the application and popularization of the soil improved by metakaolin-based geopolymer binder in engineering.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Rubberized alkali-activated concretes were designed.•Concrete containing 30% of WRTCs as natural aggreagtes replacement achieved adequate strength performance.•Inclusion WRTCs led to enhance the ...ductility of proposed concrete.•Concretes performance was evaluated experimentally and numerically.
This paper evaluated feasibility of using the waste rubber tire crumbs (WRTCs) as partial replacement for the natural aggregates in production of alkali-activated rubberized concrete (AARC). Numerical model calculations using the neural network technique were performed to evaluate the overall performance of the proposed rubberized concretes in terms of the compressive strength, splitting tensile strength, flexural strength, water absorption, carbonation depth and impact resistance to dynamic load. The AARC modified with 30% of WRTCs as the natural aggregates replacement showed improved mechanical strength wherein the compressive strength after the curing age of 28 days was 30 MPa, indicating its suitability for diverse construction applications. Inclusion of WRTCs as substitute to the natural aggregates was shown to improve the concrete ductility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The optimal mixing ratio of AAB in CS was studied.•The optimal BF content and length of BFGSCS were investigated.•The strength performance of BFGSCS was evaluated.•The textural, structural, and ...morphological characteristics of BFGSCS were analysis.•The contribution of BF to the toughening mechanisms of GSCS was discussed.
Geopolymers are recently regarded as superior sustainable alkali-activated binders (AAB) for soil improvement due to their good bonding properties. In this study, the mixture of sodium silicate (Na2SiO3) and quicklime (CaO) was used as alkali-activator (AA) for preparing AAB employing metakaolin (MK) as a precursor. The unconfined compression tests (UCT) were performed to optimize the material ratio of metakaolin-based geopolymer-stabilized clay soil (GSCS) and explore the optimum content and length of basalt fiber (BF) in GSCS. The optimum mixture was then better characterized by further experiments, including direct shear test, indirect tensile test, diffraction analysis, and microstructural analysis, and compared with other binders such as ordinary Portland cement (OPC) and lime. Results indicate that the unconfined compressive strength (UCS) of GSCS increases first and then decreases with AAB and BF contents and the length of BF. The UCS of BF-reinforced GSCS (FRGSCS) is optimum when the mass ratio of AAB in clay soil (CS) is approximately 15%, and the content and length of BF are 0.4% and 12 mm, in which the mass ratio of MK and AA in AAB is approximately 2: 1, and the mass ratio of Na2SiO3 and CaO in AA is approximately 1: 0.8. Comparison experiments on strength performance indicate that FRGSCS is consistently superior to GSCS, OPC soil (OPCS), lime soil (LS), and CS. The diffraction analysis and the microstructural analysis show that the weak alkalinity of GSCS results in poor geopolymerization of AAB in the early curing age but rapid development of aluminosilicate gels in the later curing age. The contribution of fibers to the toughening mechanisms of GSCS shows that the fiber-matrix interaction would be the dominant effect controlling the strength of FRGSCS. The results of this study provide a parameter basis for the application and popularization of FRGSCS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Sustainable concretes were designed using wastes of blast furnace slag, tyres and glass bottles.•Microstructures and strength performance of the modified concretes were evaluated.•Inclusion of waste ...glass nanoparticles was shown to improve the concretes strength performance.
Production of high strength and sustainable concrete by recycling various industrial wastes in an eco-friendly way to reduce the landfill problems remains challenging. Ever-increasing disposal of million tons of waste tyres worldwide posed serious environmental concern. The reuse of waste tyres in concrete as fine and coarse aggregates was shown to enhance its strength performance and solve the landfills-related environmental issues. Thus, new types of rubberized concrete mixes with improved bond zone and strength performance were produced by combining the waste rubber tyre aggregates (WRTAs), waste glass bottle nanoparticles (WGBNPs) and ground blast furnace slag (GBFS) with ordinary Portland cement (OPC). The designed concrete mixes contained 30% of crumb rubber as substitute of the natural fine and coarse aggregates wherein OPC was replaced by 20% of GBFS and various WGBNPs contents (3, 6, 9 and 12%). The workability performance, microstructures, and strength properties of the proposed mixes were evaluated using various tests. Concrete containing 6% of WGBNPs showed significant enhancement in the bond zone between cement paste and crumb rubber surface wherein the compressive strength was increased by 14% compared to the control specimen. The microstructures analyses of WGBNPs blended concretes displayed the formation of dense gels and less pores with acceptable engineering properties. It was asserted that concretes obtained by blending GBFS, WGBNPs and WRTAs with less OPC can be the potential green construction materials with immense benefits for the environment, thus minimizing the greenhouse gases emission and landfill requirements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
With the increasing application and demand of flexible AOLED display modules in the global market, improving the strength performance of display modules has important guiding significance for the ...development of OLED technology. In this paper, the height of the falling ball is used as the test index of strength performance, and the influence of the composite structure on the strength of the falling ball is studied through the combination of composite structure with different thicknesses and materials. It is found that in the composite structure with the same thickness, using foam instead of PI structure can obtain better ball falling results. The falling result of silica gel material is better than that of foam material, and the overall thickness of silica gel is thinner.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This study aimed to analyze the agreement between five bar velocity monitoring devices, currently used in resistance training, to determine the most reliable device based on reproducibility ...(between-device agreement for a given trial) and repeatability (between-trial variation for each device). Seventeen resistance-trained men performed duplicate trials against seven increasing loads (20-30-40-50-60-70-80 kg) while obtaining mean, mean propulsive and peak velocity outcomes in the bench press, full squat and prone bench pull exercises. Measurements were simultaneously registered by two linear velocity transducers (LVT), two linear position transducers (LPT), two optoelectronic camera-based systems (OEC), two smartphone video-based systems (VBS) and one accelerometer (ACC). A comprehensive set of statistics for assessing reliability was used. Magnitude of errors was reported both in absolute (m s
−1
) and relative terms (%1RM), and included the smallest detectable change (SDC) and maximum errors (MaxError). LVT was the most reliable and sensitive device (SDC 0.02–0.06 m s
−1
, MaxError 3.4–7.1% 1RM) and the preferred reference to compare with other technologies. OEC and LPT were the second-best alternatives (SDC 0.06–0.11 m s
−1
), always considering the particular margins of error for each exercise and velocity outcome. ACC and VBS are not recommended given their substantial errors and uncertainty of the measurements (SDC > 0.13 m s
−1
).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•A strategy was developed to produce sustainable concrete from sustainable fly ash wastes and EM.•The feasibility of fly ash incorporating EM as alternative to OPC to get low CO2 emission concretes ...was inspected.•High performance modified concrete with early age strength up to 25 MPa was obtained.•The new developed concrete reduced the drying shrinkage and the carbonation depth.•EM and waste fly ash incorporated concretes were cost-effective and moderate energy consumption.
The demand of highly sustainable and eco-friendly construction materials with low energy consumption and carbon emission has ever been increasing globally. In this rationale, some modified concretes were prepared via the replacement of the ordinary Portland cement (OPC) by the effective microorganism (EM) and fly ash (FA) at an optimum proportion. The strength performance and microstructure properties of the produced concrete mixes as a function of the EM and FA replacements for OPC were determined. The amount of OPC in the concrete mixes was replaced by the EM and FA at four ratios for the composition optimization. Water was replaced at 5, 10, 15 and 20% by the inclusion of EM solution while FA at 10, 20, 30 and 40% was used to replace the OPC. Using the available experimental test database an Adaptive Neuro-Fuzzy Inference System (ANFIS) was developed to estimate the strength properties of the design mixes depending on each binder mass percentage. Results revealed that the engineering properties of the proposed concrete mixes were improved significantly due to the incorporation of the EM and FA as replacement of the OPC. In addition, the compressive strength of the modified concretes was increased up to 30% and the microstructures were enhanced at an early age because of the substitution of 10% of FA and EM. On top, the concrete formulated with 10% of EM and FA as replacement of OPC displayed enhanced durability as well as reduced porosity, drying shrinkage and carbonation depth of 13.3, 26.9 and 13.4% at 28 days of age, respectively. In short, the replacement of the OPC by FA and EM in the modified concrete was shown to reduce the carbon dioxide emission, energy consumption, and cost. Based on the findings, it was asserted that the designed sustainable concrete mixes may be environmental friendly with reduced green-house gases emission and landfill requirements for the FA wastes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
10.
Polygenic Profile of Elite Strength Athletes Moreland, Ethan; Borisov, Oleg V; Semenova, Ekaterina A ...
Journal of strength and conditioning research,
09/2022, Volume:
36, Issue:
9
Journal Article
Peer reviewed
Open access
ABSTRACTMoreland, E, Borisov, OV, Semenova, EA, Larin, AK, Andryushchenko, ON, Andryushchenko, LB, Generozov, EV, Williams, AG, and Ahmetov, II. Polygenic profile of elite strength athletes. J ...Strength Cond Res XX(X)000–000, 2020—Strength is a heritable trait with unknown polygenic nature. So far, more than 200 DNA polymorphisms associated with strength/power phenotypes have been identified majorly involving nonathletic populations. The aim of the present study was to investigate individually and in combination the association of 217 DNA polymorphisms previously identified as markers for strength/power phenotypes with elite strength athlete status. A case-control study involved 83 Russian professional strength athletes (53 weightlifters, 30 powerlifters), 209 Russian and 503 European controls. Genotyping was conducted using micro-array analysis. Twenty-eight DNA polymorphisms (located near or in ABHD17C, ACTG1, ADCY3, ADPGK, ANGPT2, ARPP21, BCDIN3D, CRTAC1, DHODH, GBE1, IGF1, IL6, ITPR1, KIF1B, LRPPRC, MMS22L, MTHFR, NPIPB6, PHACTR1, PLEKHB1, PPARG, PPARGC1A, R3HDM1, RASGRF1, RMC1, SLC39A8, TFAP2D, ZKSCAN5 genes) were identified to have an association with strength athlete status. Next, to assess the combined impact of all 28 DNA polymorphisms, all athletes were classified according to the number of “strength” alleles they possessed. All highly elite strength athletes were carriers of at least 22 (up to 34) “strength” alleles, whereas 27.8% of Russian controls had less than 22 “strength” alleles (p < 0.0001). The proportion of subjects with a high (≥26) number of “strength” alleles was significantly greater in highly elite strength athletes (84.8%) compared with less successful strength athletes (64.9%; odd ratio OR = 3.0, p = 0.042), Russian (26.3%; OR = 15.6, p < 0.0001) or European (37.8%; OR = 6.4, p < 0.0001) controls. This is the first study to demonstrate that the likelihood of becoming an elite strength athlete depends on the carriage of a high number of strength-related alleles.
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