Improving hydrophobicity on polyurethane-based synthetic leather through plasma polymerization for easy care effect

This study reports on the deposition of a hydrophobic coating on polyurethane (PU)-based synthetic leather through a plasma polymerization method and investigates the hydrophobic behavior of the plasma-coated substrate. The silicon compound of hexamethyldisiloxane (HMDSO), inactive gas argon (Ar), and toluene were used to impart surface hydrophobicity to a PU-based substrate. Surface hydrophobicity was analyzed by water contact angle measurements. Surface hydrophobicity was increased by deposition of compositions of 100% HMDSO, 3:1 HMDSO/toluene, and 1:1 HMDSO/toluene. Optimum conditions of 40 W, 30 s plasma treatment resulted in essentially the same initial contact angle results of approximately 100° for all three treatment compositions. The initial water contact angle for untreated material was about 73°. A water droplet took 1800 s to spread out on the plasma-treated sample after it had been placed on the sample surface. An increase in plasma power also led to a decrease in contact angle, which may be attributed to oxidization of HMDSO during plasma deposition. XPS analysis showed that plasma polymerization of HMDSO/toluene compositions led to a significant increase in atomic percentage of Si compound responsible for the hydrophobic surface. The easy clean results for the treated and untreated PU-based synthetic leather samples clearly showed that the remaining stain on the plasma-polymerized sample was less than that of untreated sample. The plasma-formed coating was both hydrophobic and formed a physical barrier against water and stain.     

Influence of Laser Peening With and Without Coating on the Surface Properties and Stress Corrosion Cracking Behavior of Laser-Welded 304 Stainless Steel

Metallurgical and Materials Transactions A - This study aims to investigate the effect of laser peening with (LP) and without coating (LPwC) process on subsurface microstructural evolution,...     

Development of a Stabilized Pan/Tilt Platform and the State of the Art

In the context of this paper, a small scale, medium precision, stabilized pan/tilt platform is developed as a prototype, which is used to compare various stabilization algorithms experimentally. The overall performance of the system depends on rigid body dynamics, structural dynamics, servo control loops, stabilization control algorithm, sensor fusion algorithm and sensory feedback such as from the IMU （inertial measurement unit）. In the case that the response bandwidth of the overall system is high enough, the same hardware can also achieve active vibration isolation. All of these design aspects are investigated in the paper via numerical models and with their experimental verification.     

Human Islet Microtissues as an In Vitro and an In Vivo Model System for Diabetes

Loss of pancreatic β-cell function is a critical event in the pathophysiology of type 2 diabetes. However, studies of its underlying mechanisms as well as the discovery of novel targets and therapies have been hindered due to limitations in available experimental models. In this study we exploited the stable viability and function of standardized human islet microtissues to develop a disease-relevant, scalable, and reproducible model of β-cell dysfunction by exposing them to long-term glucotoxicity and glucolipotoxicity. Moreover, by establishing a method for highly-efficient and homogeneous viral transduction, we were able to monitor the loss of functional β-cell mass in vivo by transplanting reporter human islet microtissues into the anterior chamber of the eye of immune-deficient mice exposed to a diabetogenic diet for 12 weeks. This newly developed in vitro model as well as the described in vivo methodology represent a new set of tools that will facilitate the study of β-cell failure in type 2 diabetes and would accelerate the discovery of novel therapeutic agents.     

Valorization of textile waste hydrolysate for hydrogen gas and levulinic acid production

The objective of this research was to explore the potential for utilizing cellulose-based waste fluff that constitute a significant portion of the solid waste of textile industry to obtain high yield hydrogen gas and levulinic acid by using two-step conversion process. In the first step, hydrothermally hydrolysis of cellulose-based waste fluff was achieved and then the hydrolysate solution was further treated by two different catalysts (Pt/AC and BT500S) in different reaction conditions for producing hydrogen gas and levulinic acid. The results showed that in reforming process the highest gasification performance and hydrogen selectivity (increased up to 25.6%) were achieved from waste fluff hydrolysate compared to other lignocellulosic/cellulosic hydrolysates studied in the literature. On the other hand, 655.3 mg/mL hydrolysate of levulinic acid was produced at the reaction temperature of 200 °C with BT500S solid acid catalyst corresponding to a higher concentration than during one-step conversion process.     

定向凝固合金DZ17G的高温低周疲劳性能研究

研究了定向凝固镍基高温合金ＤＡ１７Ｇ在８００℃下的低周疲劳性能,得到其循环应力－应弯曲线和应变－寿命曲线,并用最小二乘法回归至Ｍａｎｓｏｎ－ｏｆｆｉｎ方程的数学表达式;对疲劳断口进行了宏观及微观分析,发现裂纹主要在试样内部及近表面缺陷外萌生,裂纹一旦形成即穿晶扩展,且扩展方向垂直于加载轴。     

Supramolecular assemblies based on dative boron-nitrogen bonds

Dative boron-nitrogen bonds were found to be a useful binding motif in structural supramolecular chemistry. Crystalline cages were formed using a diboronate ester and 2,4,6-tri(4-pyridyl)-1,3,5-triazine. These cages can act as hosts for electron-rich planar aromatic systems such as triphenylene. Further, crystalline two-dimensional polymers were formed via dative B-N bonds between a triboronic ester and a ditopic pyridyl ligand. Use of an extended triboronate ester resulted in formation of a gel in toluene with a minimum gelation concentration of 0.5 wt%.     

Comparison of 4 V and 3 V electrochemical properties of nanocrystalline LiMn2O4 cathode particles in lithium ion batteries prepared by ultrasonic spray pyrolysis

Nanocrystalline LiMn₂O₄ particles were prepared by an ultrasonic spray pyrolysis method using nitrate salts at 800 °C in air atmosphere. Particle properties were characterized by the X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. In addition, cyclic voltammetry and galvanostatic tests were performed to investigate the effects of structure on electrochemical behavior of both the 4 V and 3 V potential plateaus. Particle characterization studies show that the nanocrystalline particles have spinel structure of submicron size with spherical morphology. Particles, ranging between 75 and 1250 nm, were formed by aggregation of nanoparticles. Discharge capacity of LiMn₂O₄ particles between 3.0 and 4.5 V is 70 mA h g⁻¹ and cumulative capacity between 2.2 and 4.5 V is 111 mA h g⁻¹ at 0.5 C rate. Discharge capacity at the 4 V potential region reduces to 47% of initial capacity, whereas cumulative capacity fade is 62% after 100 cycles at 0.5 C rate. Although nanocrystalline LiMn₂O₄ cathode particles exhibit good rate capability at the 4 V plateau, capacity decreased rapidly by increasing C- rates and cycling between 2.2 and 4.5 V. The loss of capacity can be attributed to phase transformation and dissolution of electrode material. Particle characterization of used cathodes showed that nanocrystalline LiMn₂O₄ electrodes partly dissolve during electrochemical cycling.     

Echocardiographic epicardial adipose tissue measurements provide information about cardiovascular risk in hemodialysis patients

Epicardial adipose tissue (EAT) is a cardiovascular risk predictor in general population. However, its value has not been well validated in maintainance hemodialysis (MHD) patients. We aimed to assess associations of EAT with cardiovascular risk predictors in nondiabetic MHD patients. In this cross‐sectional study, we measured EAT thickness by transthoracic echocardiography in 50 MHD patients (45.8 ± 14.6 years of age, 37 male). Antropometric measurements, bioimpedance analysis, left ventricular (LV) mass, carotis intima media thickness, blood tests, homeostasis model assessment for insulin resistance (HOMA‐IR) and hemodialysis dose by single‐pool urea clearence index (spKt/V) were determined. The mean EAT thickness was 3.28 ± 1.04 mm. There were significant associations of EAT with body mass index (β = 0.590, P < 0.001), waist circumference (β = 0.572, P < 0.001), body fat mass (β = 0.562, P < 0.001), percentage of body fat mass (β = 0.408, P = 0.003), percentage of lean tissue mass (β = ?0.421, P = 0.002), LV mass (β = 0.426, P = 0.002), carotis intima media thickness (β = 0.289, P = 0.042), triglyceride/high‐density lipoprotein cholesterol ratio (β = 0.529, P < 0.001), 1/HOMA‐IR (β = ?0.386, P = 0.006), and spKt/V (β = ?0.311, P = 0.028). No association was exhibited with visfatin C, high‐sensitivity C‐reactive protein, interleukin‐6, and tumor necrosis factor‐alpha (for all, P > 0.05). Body mass index, waist circumference, body fat mass, percentage of lean tissue mass, LV mass, triglyceride/high‐density lipoprotein cholesterol ratio, HOMA‐IR, and spKt/V appeared as independent predictors of EAT. EAT was significantly associated with body fat measures, cardiovascular risk predictors, and dialysis dose in MHD patients.