Design of high entropy alloys based on the experience from commercial superalloys

<div><p>High entropy alloys (HEAs) have been drawing increasing attention recently and gratifying results have been obtained. However, the existing metallurgic rules of HEAs could not provide specific information of selecting candidate alloys for structural applications. Our brief survey reveals that many commercial superalloys have medium and even to high configurational entropies. The experience of commercial superalloys provides a clue for helping us in the development of HEAs for structural applications.</p></div

An experimental study of quasi-static indentation on composite sandwich panels supported rigidly

The indentation behaviour of sandwich panels could be affected by a variation of a large number of both intrinsic and extrinsic parameters. It is thus challenging not only to identify those parameters that dominate the indentation behaviour but also to ascertain how they influence the indentation behaviour across all applications. In this work, we focus on the indentation behaviour of rigidly-supported laminate-skinned sandwich panels up to an occurrence of incipient damage. Sandwich panels were constructed with carbon/epoxy skins of two different thicknesses, each in one of two lay-ups and aluminium honeycomb core. They were tested quasi-statically using hemispherical indentor. The effects of varying the thickness of loaded skin laminates, skin laminate lay-up, indentor diameter and panel support conditions on the indentation behaviour have been examined in terms of initial critical load and incipient damage mechanisms. On a basis of the extensive examinations of obtained results, we’ve found that (1) the mechanisms of incipient damage induced in all ten groups of sandwich panels were combined delamination in the loaded skin laminate and buckled honeycomb cells without debonding and there were clear indications that induced local stresses were dominated by ILS stress of the skin laminates and through-the-thickness compressive strength of aluminium honeycomb core; (2) varying the thickness of the loaded laminate skin has got a profound influence over the indentation behaviour of the sandwich panels in terms of critical load, critical indentation and initial stiffness; (3) the increase of indentor diameter had the substantial effect on the indentation behaviour of the sandwich panels; (4) varying either the lay-up of the loaded skin laminates or support conditions had very little effect on the indentation behaviour

High temperature fatigue behavior of a near-alpha titanium alloy

High-cycle and very-high-cycle fatigue at 450 °C in near-α titanium with bi-modal microstructure are investigated. Stress-life duality appears with one data group spanning from 105 to 107 and the other from 107 to 109 cycles, characterized by surface and subsurface cracking, respectively. Misfit strain induced by the high misorientation of a particular primary α-grain relative to its surroundings, termed as local texture, promotes the subsurface fatigue-crack initiation. Fatigue strength increases up to 100 MPa owing to cyclic pre-strain at 450 °C, but the duality remains. Strain hardening by activation of prismatic slip is responsible for the improved fatigue strength.</a

The Distribution of Ni and V in Resin and Asphaltene Subfractions and Its Variation During Thermal Processes

<div><p>Ni and V deactivate catalysts and promote coking during heavy oil upgrading. Distribution of metals and metalloporphyrins, and its variation in thermal process, would benefit the more efficient upgrading. Majority of metals concentrate in resins and asphaltenes. To thoroughly study the metals distribution in these fractions, both were subdivided. It is indicated that the interactions between metalloporphyrins and asphaltenes play a significant role in metals distribution. Variation of metals distribution showed that the trend metals concentrated into heavier subfractions and was enhanced by thermal treatment and inhibited by hydrogen sources. Synergism was observed between hydrogen and hydrogen donor for the inhibition.</p></div

Surfactant-like Additives Assisted the Lateral Growth of Pentacene Films

Lateral growth of thin films is crucial for organic electronic devices, such as field-effect transistors. Here, we report a strategy to improve the lateral growth of pentacene films using rubrene as a surfactant-like additive. Atomic force microscopy (AFM) images confirm the enhanced lateral growth with the presence of rubrene, resulting in smooth and enlarged molecule domains in the films in comparison to those without rubrene. Molecular dynamics simulations are conducted to explore the interlayer diffusion of pentacene molecules during the growth. With the rubrene molecules as surfactant-like additives, mean square displacement (MSD) analysis shows that the pentacene molecules have a descending diffusion coefficient of 2.0 × 10–5 cm2 s–1, which is greater than the ascending diffusion coefficient of 1.6 × 10–5 cm2 s–1. The more descending molecules lead to an enhanced lateral growth of pentacene films, which is in good agreement with the experiments. As a result, the pentacene films grown with rubrene exhibit a rapid increase in carrier mobility over thickness due to the well-connected domains resulting from enhanced lateral growth. This finding will provide a new strategy to modulate the morphology of organic films for high-performance devices

Compatibility of Heavy Blends Evaluated by Fouling and Its Relationship With Colloidal Stability

<div><p>To predict oil compatibility is crucial because incompatibility could cause severe deposition and fouling problems. Therefore, compatibility of heavy oils and blends in different ratios were evaluated by fouling at heat transfer conditions. Thermal resistance and fouling rates were obtained on a fouling loop. Effect of colloidal stability based on asphaltene precipitation and SARA composition on fouling was also discussed. Results showed that different variations of fouling rate versus blending ratio were observed for these blending systems. For oils whose viscosities approach at heat conditions, the lower colloidal stability of blends is the higher fouling rate is. However, for oils with greatly different viscosities, inconsistency was observed between compatibility by the two indicators, which is attributed to remarkable change of flow condition. This indicates that both colloidal stability and flow condition play key roles in fouling. Oil compatibility at heat transfer condition is favored being predicted by fouling instead of correlating with the colloidal stability.</p></div

Safety and efficacy of regional citrate anticoagulation in continuous blood purification treatment of patients with multiple organ dysfunction syndrome

<div><p>The aim of this study was to discuss the safety and efficacy of regional citrate anticoagulation (RCA) on continuous blood purification (CBP) during the treatment of multiple organ dysfunction syndrome (MODS). Thirty-five patients with MODS were divided into two groups: the local citrate anticoagulation (RCA) group, and the heparin-free blood purification (hfBP) group. The MODS severity was assessed according to Marshall’s MODS score criteria. Blood coagulation indicators, blood pressure, filter lifespan, filter replacement frequency, anticoagulation indicators, and main metabolic and electrolyte indicators were analyzed and compared between RCA and hfBP groups. RCA resulted in lower blood pressure than hfBP. The filter efficacy in RCA treatment was longer than in the hfBP group. The blood clearance of creatine, blood urea nitrogen and uric acid was better in the RCA group. RCA also led to higher pH than hfBP. Neither treatment resulted in severe bleeding events. In addition, MODS score was positively correlated with prothrombin time and activated partial thromboplastin time but negatively correlated with platelet concentration. RCA is a safer and more effective method in CBP treatment; however, it could also lead to low blood pressure and blood alkalosis.</p></div

Clinical and radiographic outcomes of upper thoracic versus lower thoracic upper instrumented vertebrae for adult scoliosis: a meta-analysis

<div><p>The aim of this study was to evaluate the clinical and radiographic outcomes of upper thoracic (UT) versus lower thoracic (LT) upper instrumented vertebrae (UIV) for adult scoliosis by meta-analysis. We conducted a literature search in three databases to retrieve related studies up to March 15, 2017. The preliminary screened studies were assessed by two reviewers according to the selection criteria. All analyses were carried out using the statistical software package R version 2.31. Odds ratios (OR) with 95% confidence intervals (CI) were used to describe the results. The I2 statistic and Q statistic test were used for heterogeneity assessment. Egger's test was performed to detect publication bias. To assess the effect of each study on the overall pooled OR or standardized mean difference (SMD), sensitive analysis was conducted. Ten trials published between 2007 and 2015 were eligible and included in our study. Meta-analysis revealed that the UT group was associated with more blood loss (SMD=0.4779, 95%CI=0.3349-0.6209, Z=6.55, P<0.0001) and longer operating time (SMD=0.5780, 95%CI=0.1971-0.958, Z=2.97, P=0.0029) than the LT group. However, there was no significant difference in Oswestry Disability Index, Scoliosis Research Society (SRS) function subscores, radiographic outcomes including sagittal vertical axis, lumbar lordosis, and thoracic kyphosis, length of hospital stay, and revision rates between the two groups. No evidence of publication bias was found between the two groups. Fusion from the lower thoracic spine (below T10) has as advantages a shorter operation time and less blood loss than upper thoracic spine (above T10) in posterior long-segment fixation for degenerative lumbar scoliosis.</p></div

A 4-40 Gb/s PAM4 transmitter with output linearity optimization in 65 nm CMOS

This paper presents a 4-40 Gb/s current mode PAM4 transmitter with an optimized eye linearity. By embedding an additional mixed combiner and an extra current source into the output driver and developing a coherent scaled-replica based bias generator, the channel-length modulation caused tail-current variations for both DC and AC coupling modes can be effectively compensated. Implemented in 65 nm CMOS, the transmitter occupies an area of 1.02 mm2 and consumes 102 mW at 40 Gb/s. After applying the proposed linearity optimization, the measured eye linearity can be optimized from 1.28 to 1.01 with a single-end swing of 480 mV in AC coupling mode. © 2017 IEEE.</p

Association of off-the-job training with work performance and work-family conflict among physicians: A cross-sectional study in China

Objectives To determine whether experiences of off-the-job training in domestic (DT) and overseas study (OS) settings are associated with work performance and work-family conflict in physicians. Design, setting and participants We conducted a national cross-sectional survey in 77 public hospitals across seven provinces in China between July 2014 and April 2015. Participants were 3182 physicians. Exposure Participants were categorised into four groups: none, DT only, OS only and DT and OS. Primary outcome measures Work performance was assessed by work engagement, career attrition and patient-centred care. Work-family conflict was assessed by affecting care for family, feeling guilty towards family and receiving complaints from family. Results A total of 25.89% participants had experienced DT only, 8.71% OS only and 8.47% DT and OS. After adjustment for potential confounders, participants who had experiences of DT and OS compared with those with no training were more likely to report positive work performance (pride in work: OR=2.11, 95% CI: 1.43 to 3.10; enjoyment of work: OR=1.67, 95% CI: 1.11 to 2.51; turnover intention: OR=0.54, 95% CI: 0.38 to 0.77; early retirement: OR=0.63, 95% CI: 0.45 to 0.89; and exhaustion: OR=0.66, 95% CI: 0.45 to 0.98) and less work-family conflicts (feeling guilty towards family: OR=0.51, 95% CI: 0.35 to 0.74; and complaints from family: OR=0.66, 95% CI: 0.47 to 0.91). We found no obvious association between DT/OS experience with patient-centred care. Conclusions Physicians with DT and OS experiences are more likely to have better work performance and less work-family conflict than those without such experience. Physicians face increasing pressure to pursue continuing education and experience associated distress. Therefore, hospitals and government policy-makers should promote DT and OS