Dynamic mechanical properties of polystyrene-polydimethylsiloxane blends

It was found that commercial silicone grease incorporated accidentally into polystyrene bars yields a major dynamic mechanical loss peak at ca. ?128°C. This finding was followed up with a study of various polydimethylsiloxanes and silicone rubber, in which up to three peaks were found. In order of increasing temperature (at 1 Hz) these are the glass transition (T_g; ca. ?128°C), crystallization (T_c; ca. ?110°C) and melting peaks (T_m; ca. ?50°C). Hydrocarbon-based greases were also investigated. The results indicate that the methods employed may be of use for the investigation of the dynamic mechanical properties of small amounts of material of varying particle sizes, such as powders of cross-linked polymers, that need not be compatible with, or soluble in, the host matrix. The sensitivity of the method is such at a 1 percent by weight contamination of silicone grease in polystyrene gives a loss tangent peak of at least 0.002 above background, and emphasizes the necessary care to be taken during sample preparation to exclude unwanted substances.     

Organocatalytic Application of Direct Organo-Functionalized Mesoporous Catalysts Prepared by Microwave

The organic functional groups such as primary and quaternary amine, sulfonic acid, and amino acid, especially l-proline, have been tried to immobilize onto mesoporous materials by the direct synthesis method using microwave. Microwave induced direct functionalization enabled to get well ordered mesoporous structures and stable organic tethered groups with enhanced hydrothermal stability due to more hydrophobic surfaces as well as enhanced activity. The method is also useful for overcoming several shortcomings in the post-synthesis grafting method which suffers from pore blocking at the aperture, and difficulties in controlling the as obtained from the direct co-condensation method had their functional groups spatially loadings, as well as the dispersion of active sites. The organo-functionalized mesoporous silica dispersed on the surface which could play roles as single site catalysts. Direct tethering of organic functional groups was preferably synthesized by microwave, gave morphological control and illustrated superiority in some organocatalytic application such as Knoevenagel and Henry reactions base catalytic reaction, Claisen–Schmidt condensation, and diethyl malonate addition reactions.     

Characterizing and designing polycation-clay nanocomposites as a basis for imazapyr controlled release formulations

A novel controlled release formulation (CRF) of the herbicide imazapyr (IMP) was designed to reduce its leaching,which causes soil and water contamination. The anionic herbicide IMP was bound to polydiallyldimethylammonium-chloride (PDADMAC)-montmorillonite composites. PDADMAC adsorption reached a high loading of polymer, which resulted in charge reversal of the clay and promoted IMP binding. The composites were characterized by Fourier transform infrared, zeta potential, and X-ray diffraction measurements, indicating electrostatic interactions of the polycation with the surface, polycation intercalation in the clay and suggesting a configuration as loops and tails on the surface at high loadings. IMP binding to the composites is affected by polycation loading and flocculation. Upon adding high concentrations of IMP to a composite of 0.16 g/g, we obtained high herbicide loadings (66% active ingredient). IMP release from the CRFs applied on a thin layer of soil was substantially slower than its release from the commercial formulation (Arsenal). Accordingly, soil column bioassays indicated reduced herbicide leaching (nearly 2-fold) upon applying the CRFs while maintaining good herbicidal activity. The new PDADMAC-clay formulations are promising from the environmental and weed control management points of view.     

In Vitro Macrophage Immunomodulation by Poly(ε-caprolactone) Based-Coated AZ31 Mg Alloy

Due to its excellent bone-like mechanical properties and non-toxicity, magnesium (Mg) and its alloys have attracted great interest as biomaterials for orthopaedic applications. However, their fast degradation rate in physiological environments leads to an acute inflammatory response, restricting their use as biodegradable metallic implants. Endowing Mg-based biomaterials with immunomodulatory properties can help trigger a desired immune response capable of supporting a favorable healing process. In this study, electrospun poly(ε-caprolactone) (PCL) fibers loaded with coumarin (CM) and/or zinc oxide nanoparticles (ZnO) were used to coat the commercial AZ31 Mg alloy as single and combined formulas, and their effects on the macrophage inflammatory response and osteoclastogenic process were investigated by indirect contact studies. Likewise, the capacity of the analyzed samples to generate reactive oxygen species (ROS) has been investigated. The data obtained by attenuated total reflection Fourier-transform infrared (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) analyses indicate that AZ31 alloy was perfectly coated with the PCL fibers loaded with CM and ZnO, which had an important influence on tuning the release of the active ingredient. Furthermore, in terms of degradation in phosphate-buffered saline (PBS) solution, the PCL-ZnO- and secondary PCL-CM-ZnO-coated samples exhibited the best corrosion behaviour. The in vitro results showed the PCL-CM-ZnO and, to a lower extent, PCL-ZnO coated sample exhibited the best behaviour in terms of inflammatory response and receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated differentiation of RAW 264.7 macrophages into osteoclasts. Altogether, the results obtained suggest that the coating of Mg alloys with fibrous PCL containing CM and/or ZnO can constitute a feasible strategy for biomedical applications.     

Process design and techno‐economic analysis of ethyl levulinate production from carbon dioxide and 1,4‐butanediol as an alternative biofuel and fuel additive

Carbon dioxide capture, utilization, and storage (CCUS) is one of the promising negative emission technologies (NET). Within various CCUS routes available, CO₂ conversion into fuels is one of the attractive options. Currently, most of CO₂ conversion into fuels requires hydrogen, which is expensive and consume large energy to produce. Hence, a different route of producing fuel from CO₂ by utilizing 1,4‐butanediol as the raw material is proposed and evaluated in this study. This alternative route comprises production of levulinic acid from the reaction between CO₂ and 1,4‐butanediol and production of ethyl levulinate, an alternative biofuel and biofuel additive, via an esterification reaction of levulinic acid with ethanol. The process is designed and simulated according to the available data and evaluated in terms of its technical features. Because of the unavailability of reaction data for synthesis of levulinic acid from 1,4‐butanediol and CO₂, several assumptions were taken, which may implicate the accuracy of the studied design. This technical evaluation is followed by cost estimations and sensitivity analysis. Because of the free CO₂, the profitability of the plant depends strongly on the prices of the other chemicals and the price difference between 1,4‐butanediol (raw material) and ethyl levulinate (product). Monte Carlo simulation indicates that the proposed plant will always be profitable if the ethyl levulinate is slightly more expensive than the 1,4‐butanediol, highlighting that the process of producing ethyl levulinate from CO₂ is economically profitable. Future research should be directed towards a catalytic system that can effectively convert CO₂ into levulinic acid, by‐products produced from the two reaction steps, and reduce the excess ethanol used in the second reaction.     

Modifying Crystallinity,Morphology, and Photophysical Properties of Carbon Nitride by Using Crystals as Reactants

Here we show a general method to improve the crystallinity of carbon nitride nanosheets by using melamine crystals as reactants for the high temperature synthesis. Additionally, the crystals were calcined in a sealed ampoule, which provides a pressurized environment, yielding crystalline carbon nitride nanosheets that display altered morphology and photophysical properties compared to the reference materials. Electronic microscopy, optical and photoelectrochemical measurements prove the modifications of parameters such like band structure, charge recombination or inter-layer distance. The new growth strategy presented here opens many opportunities for the design of crystalline materials with tailored properties for different applications.     

Selective Sampling Using the Query by Committee Algorithm

We analyze the query by committee algorithm, a method for filtering informative queries from a random stream of inputs. We show that if the two-member committee algorithm achieves information gain with positive lower bound, then the prediction error decreases exponentially with the number of queries. We show that, in particular, this exponential decrease holds for query learning of perceptrons.     

Story Albums: Creating Fictional Stories From Personal Photograph Sets

We present a method for the automatic creation of fictional storybooks based on personal photographs. Unlike previous attempts that summarize such collections by picking salient or diverse photos, or creating personal literal narratives, we focus on the creation of fictional stories. This provides new value to users, as well as an engaging way for people (especially children) to experience their own photographs. We use a graph model to represent an artist‐generated story, where each node is a ‘frame’, akin to frames in comics or storyboards. A node is described by story elements, comprising actors, location, supporting objects and time. The edges in the graph encode connections between these elements and provide the discourse of the story. Based on this construction, we develop a constraint satisfaction algorithm for one‐to‐one assignment of nodes to photographs. Once each node is assigned to a photograph, a visual depiction of the story can be generated in different styles using various templates. We show results of several fictional visual stories created from different personal photo sets and in different styles.     

Investigation of ITS-90 Inconsistencies in Overlap Region of the Water-indium,Water-tin,and Water-zinc Sub-ranges

One of the significant uncertainties in Standard Platinum Resistance Thermometer (SPRT) calibration by fixed-points method is Type I non-uniqueness (sub-range inconsistencies). Sub-ranges water-tin (W ₉ ) and water-indium (W ₁₀ ) lies in the water-zinc (W ₈ ) sub-range of the International Temperature Scale of 1990. Therefore, three sub-range inconsistencies [W ₈ and W ₉ (SRI _8–9 ), W ₈ and W ₁₀ (SRI _8–10 ), and W ₉ and W ₁₀ (SRI _9–10 )] occur. This paper investigated these inconsistencies using the calibration data of 12 SPRTs from six manufacturers. The result shows that the magnitude of the inconsistency for SRI _8–9 , SRI _8–10 , and SRI _9–10 are about 2.5, 2.2 and 1.8 mK, respectively.