Controlling the shape of the molecular weight distribution for tailored tensile and rheological properties in thermoplastics and thermoplastic elastomers

Thermoplastics and thermoplastic elastomers compose roughly 80 percent of all polymeric materials manufactured today and play an important role in numerous sectors of modern society. While the effects of molecular weight and dispersity (Ð) on the tensile and rheological properties of these materials are well-known, only recent studies have evidenced the profound influence of the shape of the molecular weight distribution (MWD) on polymer properties. This development is largely due to the emergence of new synthetic strategies to control higher moments of the MWD. In this Perspective, we describe recent advancements by our group in understanding the effect of MWD shape on the mechanical and rheological properties of thermoplastics and thermoplastic elastomers. We highlight means to exploit MWD shape for improved processability and performance and discuss future directions in this field.     

Time-scale through-thickness interphase in polymer matrix composites including hygrothermal treatment

For the first time, the physical effects of long-term environmental conditions on through-thickness interphase in polymer matrix composites (PMCs) were studied. Atomic force microscopy (AFM) -based Peak Force Quantitative Nanomechanical Mapping (PF QNM) technique was utilized to study the effects of heat and humidity on the mechanical properties of interphase at nanometer resolution. Samples were aged with a heat of 60 °C and relative humidity of 90% for up to 2 years. The width of the interphase is uneven and ‘river-like’ through the thickness in unaged and aged composites. The width of interphase depends on its location and the degree of moisture saturation. The difference in thickness of the interphase, through the thickness, reduces with exposure time. While the mechanism of expansion and shrinkage of interphase is different through-thickness, the range of material modulus is almost the same through-thickness in unaged and aged conditions. Rate of debonding increases from unaged to one-year aged and reduces in the second year of exposure.     

Engineering of Portable Smartphone Integrated with Liposome-Encapsulated Curcumin for Onsite Visual Ratiometric Fluorescence Imaging of Hypochlorite

Precisely onsite monitoring of hypochlorite (ClO⁻) is of great significance to guide its rational use, reducing/avoiding its potential threat toward food safety and human health. Considering ClO⁻ could quench fluorescence of curcumin (CCM) by oxidizing the o-methoxyphenol of CCM into benzoquinone, a portable ratiometric fluorescence sensor integrated with smartphone was designed for realizing the visual point-of-care testing (POCT) of ClO⁻. The amphiphilic phospholipid polymer was used as carrier to wrap curcumin, forming a novel liposome-encapsulated CCM, which provided a scaffold to bind with [Ru(bpy)₃]²⁺ through electrostatic interaction, thus assembling [Ru(bpy)₃]²⁺-functionalized liposome-encapsulated CCM ([Ru(bpy)₃]²⁺@CCM-NPs). Further integrated with smartphone, visual imaging of [Ru(bpy)₃]²⁺@CCM-NPs could be achieved and the accurate onsite detection of ClO⁻ could be realized with a detection limit of 66.31 nM and a linear range of 0.2210 to 80.0 μM. In addition, the sensor could monitor ClO⁻ in real samples with an onsite detection time of ∼154.0 s.     

Real-time soft-error rate measurements: A review

The real-time (or life testing) soft-error rate (SER) measurement is an experimental reliability technique to determine the soft error sensitivity of a given component, circuit or system from the monitoring of a population of devices subjected to natural radiation and operating under nominal conditions. This review gives a survey over recent real-time SER experiments, conducted in altitude and/or underground, and investigating modern CMOS logic technologies, down to the 40 nm technological node. The review also includes our different contributions conducted during the last decade on the ASTEP Platform (Altitude Single Event Effects Test European Platform) and at the LSM facility (Underground Laboratory of Modane) to characterize soft error mechanisms in advanced static (SRAM) memories. Finally, the review discusses the specific advantages and limitations of this approach as well as its comparison with accelerated tests using intense particle beams or sources.     

Gas chromatography–electron ionization–mass spectrometry quantitation of valproic acid and gabapentin,using dried plasma spots,for therapeutic drug monitoring in in‐home medical care

A simple and sensitive gas chromatography–electron ionization–mass spectrometry (GC‐EI‐MS) method using dried plasma spot testing cards was developed for determination of valproic acid and gabapentin concentrations in human plasma from patients receiving in‐home medical care. We have proposed that a simple, easy and dry sampling method is suitable for in‐home medical patients for therapeutic drug monitoring. Therefore, in the present study, we used recently developed commercially available easy handling cards: Whatman FTA DMPK‐A and Bond Elut DMS. In‐home medical care patients can collect plasma using these simple kits. The spots of plasma on the cards were extracted into methanol and then evaporated to dryness. The residues were trimethylsilylated using N‐methyl‐N‐trimethylsilyltrifluoroacetamide. For GC‐EI‐MS analysis, the calibration curves on both cards were linear from 10 to 200 µg/mL for valproic acid, and from 0.5 to 10 µg/mL for gabapentin. Intra‐ and interday precisions in plasma were both ≤13.0% (coefficient of variation), and the accuracy was between 87.9 and 112% for both cards within the calibration curves. The limits of quantification were 10 µg/mL for valproic acid and 0.5 µg/mL for gabapentin on both cards. We believe that the present method will be useful for in‐home medical care. Copyright © 2014 John Wiley & Sons, Ltd.     

Ken Kunen: Algebraist

Although better known as a set theorist, Ken Kunen did important work in algebra, particularly in quasigroup theory and loop theory. This paper describes some of this work, especially his use of automated deduction tools, with a lot of attention given to projects done in collaboration with the author.     

槽式太阳能电站集热管热性能测试及回归分析

利用热平衡法对桑普生产的槽式太阳能电站集热管的热性能进行了实验测试。实验结果显示,集热管内金属吸热管温度为143.6℃、200.9℃、267.2℃和290.3℃时,集热管的漏热量为21.2 W/m、39.8 W/m、50 5 W/m、88.8 W/m。根据集热管漏热的热物理过程,提出了H=f(T_(abs),T_(amb))=aT_(abs)~4+bT_(amb)~4b+cT_(amb)形式的回归模型,并对所测试真空管漏热量进行了回归分析,得到漏热量的回归数学表达式H=9.376×10~(-10)T_(abs)~4-8.685×10~(-10)T_(amb)~4-2.309×10~(-7)T_(amb)将回归模型应用于美国国家可再生能源实验室所测试的两种集热管,回归值与实验值符合较好,说明所提出的回归模型较合理。     

Inner and outer fuzzy approximations of confidence intervals

We extend the notion of confidence region to fuzzy data, by defining a pair of fuzzy inner and outer confidence regions. We show the connection with previous proposals, as well as with recent studies on hypothesis testing with low quality data.