Konsep Proses Pemesinan Berkelanjutan

Metal industrial machining usually strongth pressure from all sectors, ether raw material industries or user metal industries. Manufacturint process which offered to all sectors industries or companies that sustainable manufakturing consist of three main factor are efective cost, enviroment and social performance

Selective methylation of toluene using CO2 and H2 to para-xylene

二甲苯（PX）是石化工业的基本有机化工原料之一，主要用于生产三大合成材料—合成树脂、合成纤维和合成橡胶。随着我国下游产业的快速发展，PX的需求量迅猛增长，进口依存度大于50%。袁友珠教授课题组提出使用CO2和H2替代甲醇作为甲苯烷基化试剂，利用CO2和H2在相对较低温度下生成的甲氧基中间体（无需经甲醇）直接与甲苯烷基化。化学化工学院2018级博士生左佳昌为论文第一作者，博士生陈伟坤、硕士生刘佳以及醇醚酯化工清洁生产国家工程实验室（厦门大学）段新平博士和叶林敏博士等参与了论文的部分研究。该研究结果已分别申请了中国发明专利（申请号201911149539.2, 2019）和国际专利（申请号PCT/CN2020/077412, 2020）。【Abstract】Toluene methylation with methanol to produce xylene has been widely investigated. A simultaneous side reaction of methanol-to-olefin over zeolites is hard to avoid, resulting in an unsatisfactory methylation efficiency. Here, CO2 and H2 replace methanol in toluene methylation over a class of ZnZrOx–ZSM-5 (ZZO-Z5) dual-functional catalysts. Results demonstrate that the reactive methylation species (H3CO*; * represents a surface species) are generated more easily by CO2 hydrogenation than by methanol dehydrogenation. Catalytic performance tests on a fixed-bed reactor show that 92.4% xylene selectivity in CO-free products and 70.8% para-xylene selectivity in xylene are obtained on each optimized catalyst. Isotope effects of H2/D2 and CO2/13CO2 indicate that xylene product is substantially generated from toluene methylation rather than disproportionation. A mechanism involving generation of reactive methylation species on ZZO by CO2 hydrogenation and migration of the methylation species to Z5 pore for the toluene methylation to form xylene is proposed.This work was supported by the National Key Research and Development Program of China (2017YFA0206801), the National Natural Science Foundation of China (21972113), and the Program for Innovative Research Team in Chinese Universities (IRT_14R31).该工作得到了国家重点研发计划（2017YFA0206801）、国家自然科学基金（21972113、91545115）和教育部创新团队（IRT_14R31）的资助

Enhanced free surface mobility facilitates the release of free-volume holes in thin-film polymer glasses

The concept of free volume underpins the variations in polymer dynamics. Annihilation of free-volume holes through diffusion to surfaces has been proposed to determine the vitrification of the confined polymers. In this work, we assessed the hole diffusion dynamics in glassy thin poly (ethylene terephthalate) films with various thicknesses using a strategy based on covering the film surface with crystals of different sizes, which allows for changing the hole diffusion efficiency, thus tuning the glass transition temperature of the thin film (Tgfilm). The apparent activation energy for hole diffusion (Ea,hole) in the thin films was elucidated by modeling the correlation between Tgfilm and surface coverage of crystals using the free-volume hole diffusion model. Our results demonstrated a trend of linear decrease in Ea,hole with the increasing inverse film thickness (h–1), suggesting that the presence of a free surface with faster dynamics promotes hole diffusion in thin films. This finding demonstrates that the free volume release in thin films and thus the confined polymer dynamics can be modulated by changing the free surface properties of the films.B.Z. acknowledges financial support from Natural Science Foundation of China (Grant nos. 21973083) and Projects of International Cooperation and Exchanges NSFC (Grant nos. 22011530456). D.C. acknowledges financial support from the project PGC2018-094548-B-I00 (MICINN-Spain and FEDER-UE) and the project IT-1175-19 (Basque Government).Peer reviewe

N-terminal pro-B-type natriuretic peptide for the prognostic prediction of severe enterovirus 71-associated hand, foot, and mouth disease

Objective: The aim of this study was to determine whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) can predict impending brainstem encephalitis, pulmonary edema, pulmonary hemorrhage, cardiopulmonary failure, and death in children with severe enterovirus 71 (EV71)-associated hand, foot, and mouth disease (HFMD). Methods: Plasma NT-proBNP levels of 282 children with severe EV71-associated HFMD were measured. Results: NT-proBNP levels were significantly higher in patients with elevated blood glucose (>7.8 mmol/l) and increased white blood cell counts (>14 × 109/l). HFMD patients who had no complications had significantly lower NT-proBNP values than patients who died or had complications (p < 0.05). The area under the receiver operating characteristic (ROC) curve was 0.73, 0.87, 0.91, 0.93, and 0.92 to discriminate between patients with and without brainstem encephalitis, pulmonary edema, pulmonary hemorrhage, circulatory failure, and death, respectively, using NT-proBNP. An NT-proBNP cut-off value of ≥1300 pg/ml demonstrated a high sensitivity (85.00%) and specificity (93.51%) for predicting death in critical HFMD patients. Children with severe EV71-associated HFMD and NT-proBNP measurements ≥1300 pg/ml had significantly worse overall survival compared to those with levels <1300 pg/ml (p < 0.05). Conclusions: NT-proBNP levels may be able to predict complications and mortality in children with severe EV71-associated HFMD disease in the intensive care unit. Serum NT-proBNP values ≥1300 pg/ml on admission could be indicative of circulatory failure and increased mortality

Impact of the α‑Methyl Group (α-CH₃) on the Aggregation States and Interfacial Isotherms of Poly(acrylates) Monolayers at the Water Surface

Polymer monolayers at liquid surfaces have attracted considerable attention as tools to construct molecular devices with unique properties. The aggregation states of chains within the monolayers must be understood as the first benchmark to establish molecular designs for the devices. It has been reported that large differences exist in surface pressure–area isotherms of polyacrylates and polymethacrylates at the water surface, although they differ chemically only by the absence of an alpha methyl group (α-CH₃) in the former. Herein, we carried out experiments using sum-frequency generation vibrational spectroscopy, atomic force microscopy and infrared reflection absorption spectroscopy to explore the changes of the aggregation state and interaction of four poly­(acrylates) (i.e., poly­(methyl acrylate), PMA; poly­(ethyl acrylate), PEA; poly­(methyl methacrylate), PMMA; poly­(ethyl methacrylate), PEMA) at the water surface during compression. In the case of PMA and PEA without α-CH₃, the polymer chains adopt an expanded 2-D random-coil conformation. The methyl group in the ester side chain (s-CH₃), which is the origin of the surface pressure variation, is increasingly ordered with compressing of the surface, leading to the <i>expanded</i>-type isotherms. Nevertheless, since chains of PMMA and PEMA were collapsed into compact globules, the s-CH₃ orientation becomes invariant on compression, giving rise to more <i>condensed</i> isotherms with faster increase of surface pressure with compression. Weaker hydration effects and suppressed segmental mobility due to introduction of an α-CH₃ group was responsible for the condensed molecular conformation and reduced structural compressibility of the monolayers of PMMA and PEMA

Segmental Relaxation Dynamics of the Core and Corona in a Single Dry Micelle

The segmental relaxation dynamics of the core and the corona in a single dry spherical micelle comprising a polystyrene (PS) or poly­(methyl methacrylate) (PMMA) core and a poly­(acrylic acid) (PAA) corona, along with the effects of the micelle density and the chain length of the core-forming and corona-forming polymers, were investigated by AFM. The results showed that the segmental relaxation temperature in the micelle core was close to its bulk <i>T</i>_g and independent of the micellar structure, such as micelle size, density, and corona thickness. By contrast, the segmental relaxation temperature in the micelle corona is dependent on the micellar structure. The depressed chain mobility in the corona was enhanced as the micelle density and the length of both the corona-forming and core-forming blocks increased. This phenomenon was attributed to conformational entropy loss in the micelle corona because of the chain adopting a conformation more perpendicular to the core as the micelle size and density increased

Segmental Relaxation Dynamics of the Core and Corona in a Single Dry Micelle

The segmental relaxation dynamics of the core and the corona in a single dry spherical micelle comprising a polystyrene (PS) or poly­(methyl methacrylate) (PMMA) core and a poly­(acrylic acid) (PAA) corona, along with the effects of the micelle density and the chain length of the core-forming and corona-forming polymers, were investigated by AFM. The results showed that the segmental relaxation temperature in the micelle core was close to its bulk <i>T</i>_g and independent of the micellar structure, such as micelle size, density, and corona thickness. By contrast, the segmental relaxation temperature in the micelle corona is dependent on the micellar structure. The depressed chain mobility in the corona was enhanced as the micelle density and the length of both the corona-forming and core-forming blocks increased. This phenomenon was attributed to conformational entropy loss in the micelle corona because of the chain adopting a conformation more perpendicular to the core as the micelle size and density increased

Rhabdomyolysis-Induced Acute Kidney Injury Under Hypoxia and Deprivation of Food and Water

Background: To investigate the renal pathophysiologyin rhabdomyolysis-induced acute kidney injury (AKI) in rats under hypoxia and deprivation of food and water (HDFW), thus broadening the knowledge about rhabdomyolysis-induced AKI in massive earthquake. Methods: Male Wistar rats weighing 200-230g were randomized into control, rhabdomyolysis (R), HDFW and rhabdomyolysis in combination with HDFW (R/HDFW) group. Experimental rhabdomyolysis rat model was established through clamping hind limb muscles, HDFW model rats were kept in 10% hypoxic chamber unavailable to food and water. At 1, 3, 5, 7, 9, 11d after treatment, serum creatinine (Scr) level, renal index, renal structural changes and cell apoptosis were analyzed. Results: After R, HDFW, R/HDFW treatment, the animals showed significantly higher Scr levels than the control group. Renal index in R and R/HDFW groups elevated remarkably compared with that in control and HDFW group. The results of histopathology, ultra-structure and apoptosis assay suggested that rhabdomyolysis caused renal tubular injury, HDFW treatment resulted in renal vascular dilation, tissue congestion and tubular cell damage. In addition, more severe renal lesion appeared in R/HDFW. Conclusions: We conclude that the association of experimental rhabdomyolysis with HDFW results in a different functional and histological pattern. The rhabdomyolysis-HDFW combination causes more severe renal injury

Relationship between Segmental Relaxation of Polystyrene Films and Stick–Slip Behavior during Dynamic Wetting of Liquid Droplets on Their Surfaces

A novel method was previously reported for detecting the glass transition of thin polystyrene (PS) films by correlating the relationships between the temperature-dependent viscoelasticity of the PS films and stick–slip behavior on their surfaces during dynamic wetting of liquid droplets. In the present study, the frequency dependence of the stick–slip behavior is investigated. The results show that the stick–slip behavior of liquid dynamic wetting on PS films is dependent on the contact line velocity, which is related to the deformation frequency of the PS surface during the moving liquid front. The stick–slip behavior was revealed to be determined by a dimensionless parameter (ξ), which is the ratio of the PS segmental relaxation time (τ_α) and the characteristic time (τ_c) for PS surface deformation near the droplet contact line. When ξ is close to 1 (τ_α ≈ τ_c), the Δθ (jumping angle), a scale of the stick–slip behavior, reaches a maximum. This correlation between Δθ and ξ demonstrates that the stick–slip behavior is related to the energy dissipation caused by the PS α-relaxation process, and the peak temperature (or frequency) in Δθ corresponds to the α-relaxation temperature (time) of the polymer. These results strongly demonstrate that the utilization of the stick–slip behavior is a creditable method, similar to dynamic viscoelastic measurement, for probing the glass transition and segmental relaxation of thin polymer films