Triple Research Articles

Flow Behavior and Mechanical Properties of Multi-Pass Thermomechanically Processed 7075 Al-Alloy

Research on multi-pass hot processing of 7075 Al-alloy was rarely discussed. This study aims to design and evaluate different thermomechanical processing strategies (TMPS) to produce 3 mm-thick sheets of 7075 Al-alloy. A physical simulation was performed using the hot compression test of a Gleeble 3500 to study flow mechanisms and microstructural evolution, while an experimental investigation was carried out using a rolling mill to examine the effect of TMPS on the mechanical properties. Four hot forming strategies were designed and tested at a constant strain rate of 0.1 s−1 over a temperature range of 200–450 °C. These strategies involved applying a constant amount of deformation of 65–70% in single (SP), double (DP), triple (TP), and quadruple (QP) passes of thermomechanical processing to study the influence of multi-pass thermomechanical processing on the final mechanical properties and industrial feasibility. The microstructure analysis showed a significant refinement and more uniform distribution of precipitates with an increasing number of passes, as observed through optical micrographs and the full width at half maximum (FWHM)-position relationship of XRD data. The results indicate that QP is the optimum strategy for producing the best mechanical properties in the shortest production time.

Quality of Life and Concurrent Procedures in Truncal Body Contouring Patients: A Single-Center Retrospective Study.

Body contouring procedures provide patients with a meaningful improvement in health-related quality of life (QoL). We aim to compare the difference between the QoL in patients undergoing a single post-bariatric abdominal body contouring procedure (BCP) and those undergoing two or more concurrent procedures. Patients evaluated for post-bariatric BCP were identified and administered the BODY-Q©. Patient demographics, clinical and operative characteristics, surgical outcomes, cost data, and absolute change in QoL scores were analyzed using descriptive statistics, chi-square, and Mann-Whitney U-test, between patients who underwent single (SP), double (DP), or triple (TP) concurrent procedures. A total of 45 patients were included. The median age was 52 years old ([IQR] ±13). The majority were female (71.1%) and African-American (55.5%). The most common single procedure was panniculectomy (75%). Surgical site occurrences, readmissions, and the complication composite outcome did not differ between groups (p>0.05). No difference was seen between SP and DP QoL score (p>0.05). The DP had a statistically lower net QoL score compared with TP cohort in four domains. The SP had a statistically lower net QoL score compared with the TP in three domains. Average total cost for patients receiving an SP was $8,048.44, compared with $19,063.94 for DP (p<0.01), and $19,765.02 for TP (p>0.05). Body contouring procedures are associated with improvements in QoL irrespective of the number of concurrent procedures. Further improvement in psychological well-being occurs for patients who proceed with double concurrent procedures, albeit with an increase in cost. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Process evaluation of a randomised controlled trial of a pharmacological strategy to improve hypertension control: protocol for a qualitative study

IntroductionGlobally, the prevalence of uncontrolled hypertension is high, particularly in low- and middle-income countries. There is a critical need for strategies to improve hypertension control. The early use of a...

Mechanical and Tribological Performance of Luffa cylindrica Fibre-Reinforced Epoxy Composite

This work focuses on the mechanical properties and solid particle impact behaviour of Luffa cylindrica fibre (LCF)-reinforced epoxy composites. Single (SL)-, double (DL)-, and triple (TL)-layered composites were prepared using the general hand lay-up technique. The erosive wear test was carried out using an air jet erosion tester according to the ASTM G76 standard. The erodent used was silica sand particles (200 ± 50 µm). The experimental parameters studied for the erosion rate of the LCF epoxy composites were impingement angle (30° to 90°) and particle velocity (48 m/s to 82 m/s). Analysis of the results revealed that at the peak erosion rate, semi ductile behaviour of the composite was apparent. Possible erosion mechanisms were discussed and were investigated using scanning electron microscopy (SEM).

Cardiovascular and Metabolic Responses to On-Water Upwind Sailing in Optimist Sailors.

To explore the cardiovascular and metabolic responses of 9 Optimist sailors (12.7 ± 0.8 y, 153 ± 9 cm, 41 ± 6 kg, sailing career 6.2 ± 1 y, peak oxygen uptake [VO2peak] 50.5 ± 4.5 mL · min-1 · kg-1) during on-water upwind sailing with various wind intensities (W). In a laboratory session, peak V˙O2, beat-by-beat cardiac output (Q),mean arterial blood pressure (MAP), and heart rate (fH) were measured using a progressive cycle ramp protocol. Steady-state VO2, Q, MAP, and fH at 4 submaximal workloads were also determined. During 2 on-water upwind sailing tests (constant course and with tacks), W, Q, MAP, and fH were measured for 15 min. On-water VO2 was estimated on the basis of steady-state fH measured on water and of the individual ΔVO2/ΔfH relationship obtained in the laboratory. VO2, fH, and Q expressed as percentage of the corresponding peak values were linearly related with W; exercise intensity during on-water sailing corresponded to 46-48% of VO2peak. MAP and total vascular peripheral resistance (TPR = MAP/Q) were larger (P < .005) during on-water tests (+39% and +50%, respectively) than during cycling, and they were correlated with W. These responses were responsible for larger values of the double (DP) and triple (TP) products of the heart during sailing than during cycling (P < .005) (+37% and +32%, respectively). These data indicate that the cardiovascular system was particularly stressed during upwind sailing even though the exercise intensity of this activity was not particularly high.

LOWER LIMB FUNCTIONAL ASYMMETRIES IN YOUNG SOCCER PLAYERS: DO DIFFERENCES EXIST BETWEEN DIFFERENT AGE GROUPS?

BackgroundFunctional asymmetries of the lower limbs(FA) have been recognised as a potential source of injury risk of in soccer players;moreover a difference in strength performance between the lower limbs exceeding...

Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume–Capel model

The nature (time variation) of response magnetization m(wt) of the spin-1 Blume–Capel model in the presence of a periodically varying external magnetic field h(wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m(wt) and h(wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical (•), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results.

Many-body exchange effects in clusters of rare gases with a chromophore: He2CO2

The many-body exchange effects up to the 5-body have been analyzed in terms of possible mechanisms by which the intermolecular electron exchange is carried out. The terms corresponding to single (SE), triple (TE), double (DE), and quadruple (QE) exchanges are identified, and their diagrammatic interpretation given. It is demonstrated that they require different physical interpretations, as well as display different angular and radial behaviors. The 3-body SE and TE terms were calculated ab initio, and analyzed for a variety of geometries of the He2CO2 cluster. The anisotropy of SE over the wide range of configurations is consistent with the electrostatic model of the exchange quadrupole of He2, interacting with the permanent quadrupole of CO2. The behavior of TE may be rationalized by considering the Pauli-principle-induced distortion of the monomers involved. The influence of the CO2 asymmetric stretch on the SE, TE, and on the total exchange non-additivity has also been evaluated and discussed. The TE 4-body term in He3CO2 has been calculated and compared with the SE 3-body terms.

Influence of solvents on the direction of the reactions of vinylacetylene with nucleophilic reagents

We have found that the nature of the solvent substantially changes the direction of the reaction of vinylaee~ylene (VA) with thiols under nucleophilic conditions. While in ethanol, the main reaction is stereospecific addition to the triple bond of VA with the formation of cis-l-alkyl(aryl)thiobuta-l,3-dienes (I), and the reaction at its double bond, giving 4-alkyl(aryl)thiobuta-l,2-dienes (II) and 4-alkyl(aryl)-thiobut-l-ynes (111) has a subsidiary nature [I], in an aprotic solvent (AS) (dioxane, THF), the allene compounds (]7:) are obtained a lmost exclusively. These resu l t s confirm the hypothesis put forward previously [1] that i1:~ ethanol the react ion takes place through the formation of a complex with the part icipat ion of the C=C bond of VA and a proton f rom the solvent. Under these conditions the electrophil ici ty of the tr iple bond is irLcreased while its tendency to conjugate with the C= C bond is s imultaneously decreased . In an AS, the react ion apparently takes place by an attack of the nucleophile f rom the direct ion of the C=C bond in accordance with the polar izat ion of the VA molecule [2]