An Electrically Tuned Solid‐State Thermal Memory Based on Metal–Insulator Transition of Single‐Crystalline VO2 Nanobeams

A solid‐state thermal memory that can store and retain thermal information with temperature states as input and output is demonstrated experimentally. A single‐crystal VO₂ nanobeam is used, undergoing a metal–insulator transition at ～340 K, to obtain a nonlinear and hysteresis response in temperature. It is shown that the application of a voltage bias can substantially tune the characteristics of the thermal memory, to an extent that the heat conduction can be increased ～60%, and the output HIGH/LOW temperature difference can be amplified over two orders of magnitude compared to an unbiased device. The realization of a solid‐state thermal memory combined with an effective electrical control thus allows the development of practical thermal devices for nano‐ to macroscale thermal management.     

Water transferable,customizable highly ordered honeycomb film from polystyrene foam waste for complex surface patterning in confined space

The disposal of plastic foam, mostly composed of polystyrene, poses significant environmental challenges due to its high popularity, slow degradation, and low cost. To address this problem, recycling polystyrene foam waste (PF) has emerged as a promising solution to reduce plastic pollution. This paper presents a novel approach to mass-produce highly ordered, porous honeycomb-patterned film (hc-film) using wasted PF as the raw material. The hc-film is produced using an improved phase separation (IPS) method that utilizes methanol as a suitable pore inducer and template droplet stabilizer. Methanol provides the hc-film with customizable features such as pore ordering, size, and separation. The freestanding hc-film, achieved by adopting a water-soluble polystyrene sulfonate as a scarified layer, can be transferred and utilized as a flexible mold to pattern various solid substrates with complicated surface morphologies using the pre-impregnated technique. This study demonstrates the potential of this cost-effective and efficient approach for various applications, such as super/anti-wetting surfaces, microelectronics, optical devices, sensors, and nanogenerators.     

Buckling analysis of Reissner–Mindlin plates subjected to in-plane edge loads using a shear-locking-free and meshfree method

Buckling study of plates subjected to uniformly uniaxial, biaxial in-plane compression and pure shear loads using an efficient novel meshfree method is presented in this paper. The moving Kriging (MK) interpolation technique satisfying the Kronecker delta function property is employed to construct the shape functions. To allow for the effect of transverse shear deformation on thick plates, the first-order Reissner–Mindlin plate theory (FSDT) is adopted. The new formulation enables us to eliminate shear-locking demonstrated by various numerical examples involving both thin and moderately thick plates. It is found that the results achieved by the present approach match well with those obtained by other existing numerical approaches and analytical solutions, which illustrates the applicability, the effectiveness and the accuracy of the method.     

XpressSpace: a programming framework for coupling partitioned global address space simulation codes

Complex coupled multiphysics simulations are playing increasingly important roles in scientific and engineering applications such as fusion, combustion, and climate modeling. At the same time, extreme scales, increased levels of concurrency, and the advent of multicores are making programming of high‐end parallel computing systems on which these simulations run challenging. Although partitioned global address space (PGAS) languages attempt to address the problem by providing a shared memory abstraction for parallel processes within a single program, the PGAS model does not easily support data coupling across multiple heterogeneous programs, which is necessary for coupled multiphysics simulations. This paper explores how multiphysics‐coupled simulations can be supported by the PGAS programming model. Specifically, in this paper, we present the design and implementation of the XpressSpace programming system, which extends existing PGAS data sharing and data access models with a semantically specialized shared data space abstraction to enable data coupling across multiple independent PGAS executables. XpressSpace supports a global‐view style programming interface that is consistent with the PGAS memory model, and provides an efficient runtime system that can dynamically capture the data decomposition of global‐view data‐structures such as arrays, and enable fast exchange of these distributed data‐structures between coupled applications. In this paper, we also evaluate the performance and scalability of a prototype implementation of XpressSpace by using different coupling patterns extracted from real world multiphysics simulation scenarios, on the Jaguar Cray XT5 system at Oak Ridge National Laboratory. Copyright © 2013 John Wiley & Sons, Ltd.     

Distribution of macrolides, sulfonamides, and trimethoprim in tropical waters: ubiquitous occurrence of veterinary antibiotics in the Mekong Delta

We investigated the distributions of 12 antibiotics (viz., sulfonamides, macrolides, and trimethoprim) in the water from the Mekong Delta, Vietnam, and compared them with those in the Tamagawa River, Japan. In Vietnam, only a few antibiotics (viz., sulfamethoxazole, sulfamethazine, trimethoprim, and erythromycin-H2O) were detected in the river and canals from urban and rural sites, at concentrations of 7-360 ng/L. This contrasts with the results from the Japanese urban river, where more antibiotics (sulfamethoxazole, sulfapyridine, trimethoprim, erythromycin-H20, azithromycin, clarithromycin, and roxithromycin) were detected at concentrations ranging from 4to 448 ng/L. The concentrations of sulfonamides in the Mekong Delta were comparable to those in the Tamagawa River, whereas macrolide concentrations were lowerthanthose in the Tamagawa River. The ubiquitous occurrence of sulfamethazine, used as a veterinary medicine, in the waters in Vietnam at relatively high concentrations (15-328 ng/L) was unique. Extremely high concentrations of sulfamethazine [(18.5-19.2) x 10(3) ng/L] were detected in pig farm wastewaters, and relatively high concentrations were observed in canals near chicken and pig farms. All these data suggested the potential utility of sulfamethazine as a molecular marker of livestock-source contamination. The present study demonstrated widespread inputs of veterinary medicines to waters in Vietnam.     

Making sanitation count: developing and testing a device for assessing latrine use in low-income settings

While efforts are underway to expand latrine coverage to an estimated 2.6 billion people who lack access to improved sanitation, there is evidence that actual use of latrines is suboptimal, limiting the potential health and environmental gains from containment of human excreta. We developed a passive latrine use monitor (PLUM) and compared its ability to measure latrine activity with structured observation. Each PLUM consisted of a passive infrared motion detector, microcontroller, data storage card, and batteries mounted in a small plastic housing that was positioned inside the latrine. During a field trial in Orissa, India, with ～115 households, the number of latrine events measured by the PLUMs was in good agreement with that measured by trained observers during 5 h of structured observation per device per week. A significant finding was that the presence of a human observer was associated with a statistically significant increase in the number of latrine events, i.e., the users modified their behavior in response to the observer. Another advantage of the PLUM was the ability to measure activity continuously for an entire week. A shortcoming of the PLUM was the inability to separate latrine events that occurred in immediate succession, leading to possible undercounting during high-traffic periods. The PLUM is a promising technology that can provide detailed measures of latrine use to improve the understanding of sanitation behaviors and how to modify them and for assessing the intended health, livelihood, and environmental benefits of improved sanitation.     

Chromatin remodeling in somatic cells injected into mature pig oocytes

We examined the involvement of histone H3 modifications in the chromosome condensation and decondensation of somatic cell nuclei injected into mature pig oocytes. Nuclei of pig granulosa cells were transferred into in vitro matured intact pig oocytes, and histone H3 phosphorylation, acetylation, and methylation were examined by immunostaining with specific antibodies in relation to changes in chromosome morphology. In the condensed chromosomes of pig oocytes at metaphase II, histone H3 was phosphorylated at serine 10 (H3-S10) and serine 28 (H3-S28), and methylated at lysine 9 (H3-K9), but was not acetylated at lysine 9, 14 and 18 (H3-K9, H3-K14 and H3-K18). During the first 2 h after nuclear transfer, a series of events were observed in the somatic nuclei: nuclear membrane disassembly; chromosome condensation to form a metaphase-like configuration; an increase in histone H3 phosphorylation levels (H3-S10 and H3-S28). Next, pig oocytes injected with nuclei of somatic cells were electroactivated and the chromosome morphology of oocytes and somatic cells was examined along with histone modifications. Generally, chromosomes of the somatic cells showed a similar progression of cell cycle stage to that of oocytes, through anaphase II- and telophase II-like stages then formed pronucleus-like structures, although the morphology of the spindles differed from that of oocyte spindles. The chromosomes of somatic cells also showed changes in histone H3 dephosphorylation and reacetylation, similar to oocytes. In contrast, histone H3 methylation (H3-K9) of somatic cell nuclei did not show any significant change after injection and electroactivation of the oocytes. These results suggest that nuclear remodeling including histone H3 phosphorylation and acetylation of injected somatic nuclei took place in the oocytes under regulation by the oocyte cytoplasm.     

Preparation,characterization, and properties of graphene oxide/urushiol-formaldehyde polymer composite coating

Graphene oxide (GO) was modified by 3-methacryloxypropyltrimethoxysilane (MPS) to obtain modified graphene oxide (MGO). MGO was dispersed in urushiol-formaldehyde polymer by mechanical mixing and ultrasonic dispersion, and MGO/urushiol-formaldehyde polymer (UFP) coatings with different MGO contents were fabricated. The microstructure, physico-mechanical properties, and electrochemical properties of the MGO/UFP composite coatings were investigated. The results indicated that the hardness, adhesion, and corrosion resistance of the MGO/UFP composite coatings were obviously enhanced compared with the pure UFP coatings. The hardness and the adhesion grade of the MGO/UFP composite coatings with 3.5 wt% MGO (GO, 1.5 wt%, and MPS, 2.0 wt%) reached 6H and 2, respectively. Additionally, GO connected with MPS by chemical bond and the well-dispersed MGO in UFP could significantly enhance the anticorrosion performance of the UFP coatings, which could result from bending the diffusion pathway of penetrant species in the UFP coating matrix.     

Modélisation d'un four de calcination du coke de pétrole: I. Le modèle

In this first of a two-article series, a one-dimensional steady-state mathematical model has been developed to simulate the process of calcination of petroleum coke in a rotary kiln. The model is made of 14 ordinary differential equations describing the conservation of energy and mass in the coke bed and in the freeboard gas. They are solved simultaneously using the 4th-order Adams-Moulton numerical method. The model calculates the various temperature profiles and the mass concentration profiles of the different chemical species. Special emphasis is laid on the usual process variables such as calcined coke recovery factor, and the loss of coke in the form of dust exhausted with the gas. In the second article, a complete simulation will be presented and the results discussed. Also, a comparison with existing models will be made.