bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Common Origin of Structural Superplasticity in Different Classes of Materials
Authors: Padmanabhan K. A. , Basariya M. Raviathul 
Published: April 2019

Abstract
The present model starts with an assumption that grain/ interphase boundary sliding (GBS) that is dominant during optimal superplastic flow is slower than the accommodation processes of dislocation emission from sliding boundaries, highly localized diffusion in the boundary regions and/ or grain rotation that are present as a concomitant of the GBS process. When boundary sliding develops to a mesoscopic scale (of the order of a grain diameter or more), by the alignment of contiguous boundaries, plane interface formation/ mesoscopic boundary sliding is observed. Significant and simultaneous sliding along different plane interfaces and their interconnection can lead to large scale deformation and superplasticity. The accommodation steps, being faster than GBS, do not enter the strain rate equation. Mathematical development of these ideas using transition state theory results in a transcendental strain rate equation for steady state optimal superplastic flow, which when solved numerically helps one to describe the phenomenon quantitatively in terms of two constants, the activation energy for the rate controlling process, ΔF0and the threshold stress needed to be overcome for the commencement of mesoscopic boundary sliding, σ0.The analysis also explains quantitatively texture randomization as a function of superplastic strain. It is also pointed out, without going into details, that recently the problem has been reduced to FOUR “universal” constants, viz. the mean strain associated with a unit boundary sliding event g0, specific grain boundary energy γB, which is assumed to be isotropic, N the average number of boundaries that align to form a plane interface during mesoscopic boundary sliding and “a” a grain-size- and shape- dependent constant that obeys the condition 0 <a <0.5, in terms of which one can account for superplasticity in any material. In combination with the regression equations popularized by Frost and Ashby to predict the shear modulus of any material at any temperature, these four constants allow one to predict the steady state strain rate of any structurally superplastic material accurately, including those whose superplastic response is not considered for the analysis. The details of the last mentioned result, which are unpublished, will be presented elsewhere.
Hydrogen Embrittlement of Ultrafine-Grained Austenitic Stainless Steels
Authors: Astafurova E. G. , Astafurov S. V. , Maier G. G. , Moskvina V. A. , Melnikov E. V. , Fortuna A. S. 
Published: April 2019

Abstract
The effect of electrochemical hydrogen-charging on tensile properties, mechanisms of plastic deformation and fracture micromechanisms was studied using two ultrafine-grained (UFG) Cr-Ni austenitic stainless steels. UFG austenitic structures with an average subgrain size of 200 nm for CrNiMo (316L-type) and 520 nm for CrNiTi (321-type) steel were produced using hot-to-warm ABC-pressing. Hydrogen-charging up to 100 hours weakly influences stages of plastic flow, strength properties and elongation of the UFG steels. TEM analysis testifies to hydrogen-assisted partial annihilation and rearrangement of dislocations into dislocation tangles, and to hydrogen-induced variation in ratio of low- and high-angle misorientations in UFG structure of both steels. Hydrogen-alloying promotes mechanical twinning and deformation-induced γ ® e martensitic transformation in the UFG steels under tension. Ultrafine-grained CrNiTi steel with lower stacking fault energy (SFE) is more susceptible to mechanical twinning and deformation-induced γ ® e martensitic transformation in comparison with CrNiMo steel with higher SFE. The micromechanism of the fracture in hydrogen-assisted surface layers of the steels is compositional, grain-size and hydrogen content dependent characteristic. The present results demonstrate that the steels with UFG structure possess higher resistance to hydrogen embrittlement compared to coarse-grained analogues.
Superplasticity in Ultrafine-Grained Materials.
Authors: Kawasaki Megumi , Langdon Terence G. 
Published: April 2019

Abstract
Superplasticity refers to the ability of a polycrystalline solid to exhibit a high elongation, of at least 400% or more, when testing in tension. The basic characteristics of superplastic flow are now understood and a theoretical model is available to describe the flow process both in conventional superplastic materials where the grain sizes are a few micrometers and in ultrafinegrained materials processed by severe plastic deformation where the grain sizes are in the submicrometer range. This report describes the basic characteristics of superplastic metals, gives examples of flow in ultrafine-grained materials, demonstrates the use of deformation mechanism mapping for providing a visual display of the flow processes and provides a direct comparison with the conventional model for superplastic flow. The report also describes the potential for using nanoindentation to obtain detailed information on the flow properties using only exceptionally small samples.
Mechanism of Stress-Driven Grain Boundary Migration in Nanotwinned Materials
Authors: Skiba N.V. 
Published: April 2019

Abstract
Stress-driven grain boundary (GB) migration in ultrafine-grained materials with nanotwinned structure is theoretically described. In the framework of the theoretical model, the stress-driven high-angle GB migration is accompanied by migration of twin boundaries which adjoin this GB. Energetic characteristics and critical stresses of the GB migration accompanied by the twin boundary migration are calculated.
Annealing-Induced Grain Rotation In Ultrafine-Grained Aluminum Alloy
Authors: Danilenko V. N. , Bachurin D. V. , Nazarov A. A. 
Published: April 2019

Abstract
Results of in situ transmission electron microscopic studies of annealing-induced evolution of grain boundary misorientations in ultrafine-grained aluminum alloy Al-4%Cu-0.5%Zr (wt.%) processed by high pressure torsion are presented. An experimental procedure based on the single reflection technique was applied for the measurements of orientations of individual grains before and after annealing that allowed for determining misorientations between them. The measurements revealed that relaxation processes occurring in non-equilibrium grain boundaries during short-time annealing are accompanied by a change of grain boundary misorientations, grain rotation, grain migration as well as grain growth. Obtained results were compared with theoretical studies considering the kinetics of grain rotation in discrete-dislocation as well as continuum approaches.
Influence of the Support on the Morphology of Co-Sn, Ni-Sn, Co-Ni Nanoparticles Synthesized Through a Borohydride Reduction Method Applying a Template Technique
Authors: Markova I. N. , Piskin M. B. , Zahariev I. Z. , Hristoforou E. , Milanova V. L. , Ivanova D. I. , Fachikov L. B. 
Published: April 2019

Abstract
Intermetallic (Co-Sn, Ni-Sn, Co-Ni) nanoparticles have been synthesized through a borohydride reduction with NaBH4 in aqueous solutions of the chloride salts of Co, Ni, Sn at room temperature using a template technique with a carbon support. As a result nanocomposite materials have been obtained in situ. The ratio of the metallic components has been chosen according the phase diagrams of the relevant binary (Co-Sn, Ni-Sn, Co-Ni) systems: Co:Sn=35:65, Ni:Sn=45:55, Co:Ni=50:50. As carbon supports have been used graphite and carbon powder. To avoid the nanoparticle’s aggregation b-cyclodextrin has been added to the reaction solutions. To study the influence of the supports used on the morphology, specific surface area, elemental and phase composition of the synthesized intermetallic nanoparticles and their carbon nanocomposites SEM, EDS, BET, and XRD investigation techniques have been used. The particle’s morphology varies with the different supports, but in the all cases it is typical for alloyed materials. The nanoparticles are different in shape and size and exhibit a tendency to aggregate. The last-one is due to the unsaturated nanoparticle’s surface and the existing magnetic forces. Regardless of the elemental composition, the nanosized particles are characterized by a relatively high specific surface area (SSA). The Ni-Sn nanoparticle have the largest SSA (80 m2/g), while the Co-Sn particles have the lowest SSA (69 m2/g). The use of a carrier modifies the SSA of the resulting nanocomposites differently depending on the size and shape of the carrier’s particles. The studies conducted on the intermetallic nanoparticles synthesized with various carriers demonstrate that the particle’s morphology, size, and specific surface area for the different supports are suitable for use as catalysts, electrode materials in Li-ion batteries and as magnetic materials for biomedical applications.
A Review on Mechanical and Tribological Properties of Graphite Reinforced Self Lubricating Hybrid Metal Matrix Composites
Authors: Khatkar S. K. , Suri N. M. , Kant S. , Pankaj  
Published: April 2019

Abstract
Hybrid metal matrix composites (HMMC’s) are next generation metal matrix composite materials that have the potential of gratifying recent demands of advanced energy applications in the field of aerospace, automobile and biomedical. The MMC’s have to work at elevated temperature or vacuum environment where lubrication using liquid lubricants is ineffective or difficult to achieve; moreover, liquid lubricants are not environmental friendly, since they releases pollutants into environment. Solid lubricants such as graphite, CNT’s, MoS2and graphene have been widely used as secondary reinforcements to meet such operational needs by fabricating green or environmental friendly self lubricating HMMC’s. This article outlines recent advances in the area of self lubricating HMMC’s reinforced with graphite as secondary reinforcement. The focus of the study was on mechanical and tribological behavior of Aluminum and magnesium based self lubricating HMMC’s. The effect of graphite, different hybrid reinforcements and their strengthening mechanisms are also discussed in detail.
Length Scale Plasticity: A Review from the Perspective of Dislocation Nucleation
Authors: Bagheripoor Mahdi , Klassen Robert 
Published: April 2019

Abstract
Sub-micron and nano-size material systems and components are now regularly being fabricated for use in a wide variety of new applications. These systems exhibit mechanical properties that can be drastically different from their macroscopic counterparts and recently much work has focused on the size effects on the mechanical behaviour of materials. Although the size dependent behaviour has been observed in all of the crystal structures, the governing mechanisms have been found to be different. Different theories have been proposed to describe the size dependent behaviour of metallic samples and the governing mechanisms and it is well known that the surface plays an important role in the plasticity of small scales. Some of the theories indicate the importance of surface in nucleating dislocation and some other ones consider the surface importance as its effect on truncating dislocation loops and activation of internal sources. Moreover, recent studies have revealed that while dislocation based deformation in fcc metals is not very sensitive to temperature, deformation is strongly temperature dependent in bcc metals. The effect of orientation is more clear in the size scale behavior of hcp metals. This review covers recent literature that has focused on uniaxial compression of single crystals at the sub-micron and nanometer scale. The fundamental mechanisms governing the size dependent mechanical behaviour of different crystal structures are described. The effect of fabrication process and current experimental techniques for micro and nano-compression are studied as well.
Synthesis and Properties of Zirconia-Graphene Composite Ceramics: A Brief Review
Authors: Glukharev A. G. , Konakov V. G. 
Published: April 2019

Abstract
The paper summarizes current data on ceramic zirconia-graphene composites. Basic types of graphene-containing additives and the main approaches for composite synthesis are considered. The effect of the additive type and synthesis procedure on the composite structure, mechanical (microhardness and crack resistivity) and electrical (conductivity at room and at elevated temperature) properties of the material is discussed.
EPR, Nexafs Study and Magnetic Properties of Fe-Doped Ferroelectric Ceramics
Authors: Zhuk N. A. , Lutoev V. P. , Makeev B. A. , Chezhina N. V. , Belyy V. A. , Nekipelov S. V. 
Published: April 2019

Abstract
Magnetic susceptibility and EPR of iron-containing solid solutions with layered perovskite-like structure Bi2BaNb2-2xFe2xO9-δ and Bi5Nb3-3xFe3xO15-δ have been studied. The solid solutions Bi2BaNb2-2xFe2xO9-δ as well as iron oxides FeO, Fe2O3, and Fe3O4 were studied by the NEXAFS spectroscopy. The formation of exchange-bound aggregates of Fe(III) atoms with antiferroand ferromagnetic exchange types has been found in the solid solutions. In the ESR spectra of the solid solution samples, the lines with g ≈ 2.0 and g = 4.27 having a weak shoulder at g ~ 8 were attributed to Fe(III) atoms in the octahedral field with strong rhombic distortion.
Demarcating Exercise Intensity Domains in Freestyle Swimming: Is There an Alternative to Incremental Step Test and Beats Below HRmax Method?
Authors: Piatrikova Eva , Sousa Ana C. , Willsmer Nicholas J. , Gonzalez Javier T. , Williams Sean 
Published: April 2019

Abstract
Piatrikova, E, Sousa, AC, Willsmer, NJ, Gonzalez, JT, and Williams, S. Demarcating exercise intensity domains in freestyle swimming: is there an alternative to incremental step test and beats below HRmax method? J Strength Cond Res 34(9): 2575–2584, 2020—Critical power derived from the 3-minute all-out test (3MT) was recently used to estimate the exercise intensity boundaries in competitive cyclists. Considering that physiological testing is challenging in swimming, the purpose of this study was to examine whether critical speed (CS) derived from the 3MT could be used for the same purpose in swimming. The second aim was to assess the accuracy of the 50-40 and 30-20 beats below the maximal (BBM) heart rate method, currently used by swimming coaches to demarcate boundaries between moderate-heavy and heavy-severe exercise, respectively. Thirteen swimmers completed an incremental step test (IST) and 3MT in freestyle to establish speeds at: lactate threshold (LT), lactate turnpoint (LTP), maximum aerobic speed (Smax), and CS. Using linear regression through origin, speeds at LT, LTP, and Smax were predicted at 89, 98, and 104% of CS derived from the 3MT, respectively. There were no significant differences between threshold speeds derived from the IST and 3MT (p > 0.05), and nearly perfect correlations at LT (1.21 ± 0.06; 1.21 ± 0.06 m·s−1; r = 0.92) and LTP (1.33 ± 0.07; 1.33 ± 0.07 m·s−1; r = 0.90), and very large correlations at Smax (1.40 ± 0.06; 1.40 ± 0.07 m·s−1; r = 0.88; all p < 0.0001). Speeds estimated at 50 (1.11 ± 0.08 m·s−1) and 40 BBM (1.17 ± 0.07 m·s−1) were lower compared with LT, and speeds estimated at 30 (1.23 ± 0.07 m·s−1) and 20 BBM (1.29 ± 0.07 m·s−1) were lower compared with LTP and CS (all p < 0.02). The 3MT can therefore be used as an alternative to the IST to estimate exercise intensity boundaries, in practical settings where resources or time might be limited. However, the BBM significantly underestimates speeds at LT, LTP, and CS.
Predictors of Fat Oxidation and Caloric Expenditure With and Without Weighted Vest Running
Authors: Purdom Troy M. , Mermier Christine , Dokladny Karol , Moriarty Terence , Lunsford Leigh , Cole Nathan , Johnson Kelly , Kravitz Len 
Published: April 2019

Abstract
Purdom, TM, Mermier, C, Dokladny, K, Moriarty, T, Lunsford, L, Cole, N, Johnson, K, and Kravitz, L. Predictors of fat oxidation and caloric expenditure with and without weighted vest running. J Strength Cond Res 35(7): 1865–1872, 2021—This study evaluated the effect of weighted vest running (WVR) on fatty acid oxidation (FAox) and caloric expenditure at predesignated steady-state exercise intensities. Seventeen recreationally trained runners (9 men and 8 women) performed 4 separate graded exercise tests (GXTs) separated by at least 24 hours. The first GXT was a V̇o
2max test to establish running velocities (percentage of max) at the prespecified exercise intensities (60, 65, 70, 75, and 80% V̇o
2max). The following randomized WVR trials included a control (no vest), 5% body mass (BM) vest, and 10% BM vest using 3-minute incrementally increasing steady-state stages. Indirect calorimetry was used to measure both FAox (g·min−1) and caloric expenditure (kcal·min−1) at each stage. The ANOVA/ANCOVA analysis revealed that intensity had the largest effect on and FAox (p < 0.001) while WVR had a significant main effect on both caloric expenditure and FAox (p < 0.05). Pairwise comparisons revealed that the 10% BM significantly increased caloric expenditure for all exercise intensities compared with control and 5% BM (except 60% V̇o
2max), while FAox decreased in the 10% BM 70 and 75% V̇o
2max intensities only. Marginal r-squared (

) demonstrate that when sex + fat-free mass (FFM) + fat mass (FM) were included as covariates, sex was a significant predictor of caloric expenditure but was further explained by the large FFM (kg) differences between the sexes significantly influencing caloric expenditure (

= 0.87, p < 0.001). Exercise intensity, body composition (FFM + FM), and external mass placement are relevant considerations for runners looking to maximize FAox and caloric expenditure.
Examining the Accuracy of the Polar A360 Monitor
Authors: Rider Brian C. , Conger Scott A. , Ditzenberger Grace L. , Besteman Summer S. , Bouret Claire M. , Coughlin Adam M. 
Published: April 2019

Abstract
Rider, BC, Conger, SA, Ditzenberger, GL, Besteman, SS, Bouret, CM, and Coughlin, AM. Examining the accuracy of the Polar A360 monitor. J Strength Cond Res 35(8): 2165–2169, 2021—The purpose of this study was to determine the accuracy of the Polar A360 heart rate (HR) monitor during periods of rest, walking/running, and active/passive recovery from exercise. Thirty collegiate athletes (women n = 15 and men n = 15) wore an A360 monitor and a previously validated chest HR monitor (Polar RS400) that served as the criterion measurement across a range of resting and walking/running intensities. First, subjects rested in a supine, seated, and standing position. Next, each subject walked on a treadmill at 1.6 kilometers per hour (kph). Speed was increased by 1.6 kph every 2 minutes until volitional fatigue. Then, subjects walked at 4.8 kph followed by a seated recovery stage. Heart rate was recorded in 30-second increments. Total mean difference in HR readings, percent accuracy, and intraclass correlation coefficient (ICC) analysis established the level of agreement between devices. Bland-Altman plots and a regression were used to examine the agreement between devices. The A360 demonstrated a strong correlation with the RS400 (r
2 = 0.98) across time points. The analysis of variance with repeated measures indicated an overall significant difference (p < 0.001) between devices. The A360 significantly underestimated HR during the 6.4-kph speed only (p < 0.05) (effect size 0.26). The greatest percent accuracy occurred during rest (91%) and recovery (90%). An ICC of 0.98 (SEM: 0.35) demonstrates a strong level of agreement between devices. The A360 is accurate at rest and during various walking and running speeds and thus is a device that can be used with confidence by athletes for specific training purposes. Future research should examine accuracy during weight training and other sport-specific activities.
Load-Power Relationships for High-Speed Knee Extension Exercise
Authors: Chen Ling , Davison Steve W. , Selimovic Ema A. , Mueller Rebecca E. , Beatty Samantha R. , Carter Kathy A. , Parmar Prashant J. , Symons Thorburn B. , Pantalos George M. , Caruso John F. 
Published: April 2019

Abstract
Chen, L, Davison, SW, Selimovic, EA, Mueller, RE, Beatty, SR, Carter, KA, Parmar, PJ, Symons, TB, Pantalos, GM, and Caruso, JF. Load-power relationships for high-speed knee extension exercise. J Strength Cond Res 33(6): 1480–1487, 2019—Seventy subjects did 4 knee extensor workouts with their left legs to assess load-power relationships produced on a high-speed trainer (HST; Newnan, GA, USA). Each workout is composed of 4 sets done on the HST at a different load (1, 4.4, 6.7, 9 kg). A Latin Squares Design determined load sequence per workout. Average power (AP) and peak power (PP) and those same values normalized to body mass (BM) and fat-free mass (AP/BM, PP/BM, AP/FFM, PP/FFM) were each analyzed with 2 (gender) × 4 (load) analysis of variances, with repeated measures for load. We assessed relationships between normalized loads and AP and PP values with correlation coefficients. Average power results revealed a significant interaction, with men > women at 9 kg. Peak power/body mass also yielded an interaction, with women > men at 6.7 and 9 kg. Average power/fat-free mass and PP/FFM each produced interactions, with women > men at 4.4, 6.7, and 9 kg. Correlation coefficients showed significant (r = 0.80–0.82) relationships between normalized loads and AP and PP values. In conclusion, the very low inertial resistance to initiate each repetition on this novel device may in part explain our PP/BM, AP/FFM, PP/FFM results, in which higher values were achieved by women. Our practical applications imply that the low inertial resistance for HST repetitions negates male size and strength advantages typically seen when power is measured.
Biomechanical Comparison of the Reverse Hyperextension Machine and the Hyperextension Exercise
Authors: Lawrence Michael A. , Chin Andrew , Swanson Brian T. 
Published: April 2019

Abstract
Lawrence, MA, Chin, A, and Swanson, BT. Biomechanical comparison of the reverse hyperextension machine and the hyperextension exercise. J Strength Cond Res 33(8): 2053–2056, 2019—The purpose of this study was to compare activation of the erector spinae, gluteus maximus, and biceps femoris muscles, lower back extension moment, and lower extremity range of motion (ROM) between the reverse hyperextension (RHE) and hyperextension (HE) exercises. Motion and muscle activation of the trunk and lower extremity were measured while 20 recreationally active individuals performed 2 sets of 10 repetitions of each exercise. Equivalent loads were used for each exercise. Peak, average, and integrated muscle activity, low back moment, and ROM between the trunk and pelvis and the thigh and trunk were calculated. A Wilcoxon signed-rank test (p = 0.05) revealed significantly greater integrated activity of the biceps femoris and gluteus maximus during the HE exercise. The RHE exercise generated greater peak (+129%), integrated (+63%), and mean (+78%) low back moment as compared to the HE exercise. The RHE resulted in a significantly greater thigh to trunk ROM, 76.6° compared with 64.7°. However, the RHE used less lumbar flexion, 20.4° compared with 31.1° for the HE. The RHE movement profile is preferable because it provides greater hip ROM with less angular stress and equivalent erector spinae activity.