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Graphene oxide (GO) has proved to be a highly active and reusable solid acid catalyst for glycerol esterification with acetic acid in the synthesis of bioadditives diacylglycerol (DAG) and triacylglycerol (TAG). The effects of reaction temperature, molar ratio of acetic acid to glycerol, catalyst amount and reaction time were investigated. A 90.2% combined selectivity of DAG and TAG with complete glycerol conversion was achieved at 120 °C for 6 h over GO. Final characterization shows that the active site of GO is the remaining SO 3 H group. [ABSTRACT FROM AUTHOR]

Despite 1,3-propanediol possessing high economic value, its production from glycerol hydrogenolysis is a challenging task. Herein, a series of WO x promoted Pt/Al 2 O 3 catalysts with various WO x contents were prepared and investigated for selective production 1,3-propanediol from glycerol hydrogenolysis. To explore the structure feature, these catalysts were fully characterized by BET, CO chemisorption, HRTEM, XRD ( in situ XRD), Raman, NH 3 –TPD, Py–IR, H 2 –TPR, and XPS. Among them, Pt–10WO x /Al 2 O 3 achieved the highest 1,3-propanediol yield up to 42.4%, which was ascribed to the large concentration of Brønsted acid sites, strong electronic interaction between Pt with WO x and hydrogen spillover. The strong correlation between 1,3-propanediol yield and Brønsted acid site indicated its essential role for the formation of 1,3-propanediol. Meanwhile the linear correlation between 1,2-propanediol yield and Lewis acid site gave direct evidence that Lewis acid site preferentially generated 1,2-propanediol. [ABSTRACT FROM AUTHOR]

Highlights: [•] Addition of SiO2 to PtW/Zr greatly enhanced activity and 1,3-propanediol selectivity. [•] 54.3% conversion and 52.0% 1,3-propanediol selectivity were achieved over 5PtW/ZrSi. [•] A model scheme of WO x transformation due to SiO2 doping has been built. [•] Pt and polytungstate have been identified as the dominant active phases. [•] Glycerol hydrogenolysis conforms to the dehydration–hydrogenation mechanism. [Copyright &y& Elsevier]

Highlights: [•] Adults implicitly learn the prototype and first two eigenfaces of the studied faces. [•] The prototype and eigenfaces are learned more efficiently than the studied faces. [•] The learning of the eigenfaces is as strong as the prototype learning. [ABSTRACT FROM AUTHOR]

Abstract: Flower-like ZnO microstructures have been fabricated by a facile microwave hydrothermal method (HM) with the aid of benzoic acid. The obtained products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology gradually evolved from flower bud shape to fireworks display with increase of alkalinity in the presence of benzoic acid. The formation mechanism of the flower-like ZnO microstructures was investigated briefly. Furthermore, the gas response of the flower-like ZnO microstructures has been studied to a series of organic vapors. It was found that the gas sensing properties were influenced by the size of the ZnO microstructures. The facile preparation method and the improved gas-sensing properties derived from the flower-like ZnO microstructures demonstrated their potential applications in gas sensor. [Copyright &y& Elsevier]

Highlights: [•] Alkaline metals Li, K, Rb and Cs were efficient for tune acidity of H4SiW12O40. [•] Li modified Pt–H4SiW12O40/ZrO2 exhibited superior 1,3-propanediol selectivity. [•] 1,3-Propanediol yield was proportional to the concentration of Brønsted acid sites. [•] A mechanistic scheme for glycerol hydrogenolysis to 1,3-propanediol was proposed. [•] A 120h long-term performance for Pt–H4SiW12O40/ZrO2 was achieved. [ABSTRACT FROM AUTHOR]

Abstract: We measured contrast thresholds for the identification of faces and facial expressions as a function of the center spatial frequency of narrow-band additive noise. In adults, masking of mid spatial frequencies (11–16c/fw) caused the largest elevation in contrast threshold (Experiment 1). Ideal observer analysis revealed that adults were equally sensitive to available information at low and mid spatial frequencies, both of which they used more efficiently than high spatial frequencies. The drop-off of sensitivity at high spatial frequencies began at a lower spatial frequency for recognizing facial identity than for recognizing facial expression. As a result, the critical band was higher for expression than for identity. The critical band for both identity and expression shifted to slightly lower values as distance increased (Experiment 2), a pattern indicating only partial scale invariance. Children aged 10 and 14years showed similar tuning but needed more contrast (Experiment 3). The patterns suggest that adults use finer details for recognizing facial expressions than for identifying faces, a tuning that appears as early as age 10. [Copyright &y& Elsevier]

Abstract: Carbon/carbon composites containing zirconium were prepared using chopped carbon fiber, mesophase pitch and Zr powder by the traditional process including molding, carbonization, densification and graphitization. The influence of Zr on the microstructure and properties of the composites were investigated. Results show that Zr can improve the interface bonding, promote more perfect and larger crystallites and enhance the conductive/mechanical properties of the composites. The high in-plane thermal conductivity of 464W/(mK) and excellent bending strength of 83.6MPa was obtained for a Zr content of 13.9wt% at heat treatment temperature(HTT) of 2500°C. However the conductive/mechanical properties of the composites decrease dramatically for an higher HTT of 3000°C. SEM micrograph of the fracture surface for the composites shows that lower disorder crystallite arrangement of fiber and carbon matrix come into being in the composites during HTT of 3000°C, which should be responsible for the low properties. Correlation between the content of Zr and the microstructure and properties are discussed. [Copyright &y& Elsevier]

• TiO 2 nanosheets supported Ru nanoparticles form strong interfacial Ru O Ti structure. • Ru/TiO 2 reached the highest TOF of 19,045 h−1for levulinic acid (LA) hydrogenation. • 99.1% yield of γ-valerolactone (GVL) was achieved over Ru/TiO 2. • DFT calculations clearly elucidate reaction mechanism of LA hydrogenation to GVL. • Ru/TiO 2 interface tunes rate-determining step from LA hydrogenation to cyclization. Highly efficient synthesis of valuable γ-valerolactone (GVL) by levulinic acid (LA) hydrogenation is still a challenge for Ru-based catalysts under mild condition. In this work, we have reported that ultrathin TiO 2 nanosheets supported Ru nanoparticles showed extraordinarily high catalytic activity, GVL yield (99.1%) and reusability owing to the formation of Ru O Ti interfacial structure. The turnover frequency (TOF) reached as high as 19,045 h−1 at 100 °C, much higher than those of Ru/SiO 2 , Ru/GO, Ru/MoS 2 , and commercial Ru/C. DFT calculation elucidates that the dominant reaction pathway of LA hydrogenation to GVL is preferentially hydrogenated to CH 3 CHOCH 2 CH 2 COOH*, followed by cyclization to CH 3 (OH)C 4 OH 4 OH* (GVL − OH) and final dehydroxylation, irrespective of surface structure. Compared to Ru (0 0 2) facet, Ru/TiO 2 interfacial structure changes the rate-determining step from initial hydrogenation to cyclization, which greatly declines the activation barrier from 0.81 eV to 0.48 eV. [ABSTRACT FROM AUTHOR]

Suppressing reverse water-gas-shift (RWGS) reaction is high desirable but challenging and underdeveloped for Cu/ZnO catalysts, particularly for commercial Cu/ZnO/Al 2 O 3 catalysts. Different from the current methodologies to reduce RWGS reaction, we report a simply surface silylation method for efficiently minimizing RWGS reaction over a commercial Cu/ZnO/Al 2 O 3 catalyst. This method suppresses STY CO (Space-time yield) from 97.4 to 0.7 g CO ·kg cat −1·h−1, improving STY MeOH from 20.2 to 39.9 g MeOH ·kg cat −1·h−1 and methanol selectivity from 15.1 to 92.9 mol%. The combination of characterization methods and density functional theory calculations provide insight into the suppressing mechanism of surface silylation on catalyst. A hydroxyl (on ZnO)-promoted RWGS reaction cycle is discovered, which can be efficiently inhibited by the consuming of hydroxyls via surface silyation. Our results provide a way to regulate RWGS reaction on Cu/ZnO-based catalysts and are expected to the further use of silylation strategy to tune the interconversion of CO and CO 2 via RWGS/WGS reaction on hydrogenation catalysts. [Display omitted] • Surface silylation suppresses RWGS reaction on Cu/ZnO/Al 2 O 3 for CO 2 hydrogenation, promoting S CH3OH from 15.3 to 92.9 mol%. • A Zn-OH promoted RWGS mechanism is found, i.e., H spillover from Cu to the reactants via the Zn-OHs boosts RWGS reaction. • Consuming hydroxyls via the surface silylation inhibits the H spillover and further RWGS reaction. [ABSTRACT FROM AUTHOR]

• An efficient and economic HDPy-bent material was synthesized and applied for removing 99Tc from contaminated water. 99Tc is one of the critical fission products in the treatment of wastewater and the nuclear waste repository due to its long half-life (t 1/2 = 2.13 × 105 y), high fission yield (~6%), and high mobility in the environment. The development of highly-efficient, low-cost and easily available materials that can rapidly and selectively remove 99Tc is of great significance, but remains a challenge. In this work, bentonite-based materials (HDPy-bent) were obtained through modifying bentonite with hexadecylpyridinium (HDPy) and applied for the remove of TcO 4 − as well as its surrogate ReO 4 −. The structure of HDPy-bent (e.g., the values of d 001) was evaluated and the maximum loading amount of HDPy on bentonite was found to be 200% CEC. The loaded HDPy+ might replace exchangeable cations in the inter-layer space of bentonite. Batch experiment results show that HDPy-bent could quantitatively remove TcO 4 − from aqueous solution within 3 min. The distribution coefficient (K d) of TcO 4 − in this material is up to 2.1 × 105 mL/g, which is significantly higher than most of the previously tested inorganic adsorbent materials. More importantly, HDPy-bent can selectively remove TcO 4 − in the presence of large excess (80,000 times) of competitive anions (NO 3 –, SO 4 2−, CO 3 2−, PO 4 3− and Cl−). This work demonstrates that the HDPy-bentonite is a low cost, and effective adsorbent for removing 99Tc from contaminated water. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) technique has enlarged the application of Raman spectroscopy, and the most crucial problem is the exploration of SERS-active materials. In the paper, a SERS substrate made of helical gold nanoparticles by the directed synthesis of L-glutathione (L-GSH) was proposed. Because of the large surface specific area and the uneven conduction electrons distribution for sharp tips resulted from the complex concave surface and the symmetry breaking structure, The nanostructure has shown an impressive average enhancement factor (EF) of 2.95 × 105 under off-resonant condition. This phenomenon was explained by the experimental results and finite difference time domain (FDTD) method. Finally, the SERS substrates were used to detect thiram on pear with a limit of detection (LOD) of 0.62 mg/kg and R2 of 0.9772. The proposed SERS substrates suggest the potential application of chiral molecules such as amino acids, peptides et al. in the SERS-active materials fabrication. [ABSTRACT FROM AUTHOR]

The aim of this study is to identify the best practices and future research directions for driver lane-change intention (DLCI) prediction using eye-tracking technologies based on a systematic literature review. We searched five academic literature databases and then conducted an in-depth review, structured coding, and analysis of 40 relevant articles. The literature on DLCI prediction is summarized in terms of input features, feature extraction and prediction time windows, labeling methods, and machine learning algorithms. The results show that eye tracking data features along with other data sources can be useful inputs for the prediction of DLCI. Major challenges in this line of research include determining the optimal time window for feature extraction and developing and evaluating the appropriate machine learning algorithm. Suggestions for future research and practice for DLCI prediction in intelligent vehicles are discussed. [ABSTRACT FROM AUTHOR]

Abstract: A simple and effective route for the direct synthesis of Mo2C coatings on graphite matrix is introduced for the joining of copper alloy heat sinks to graphite materials in Tokamak devices. The composition and microstructure of the Mo2C coatings on graphite, and the wetting behaviors of molten copper on coated and uncoated graphite were investigated. Results indicated that the Mo2C coatings were of several tens of micrometers depth in the graphite matrix. The coatings greatly improved the wettability of graphite by copper, and copper could be infiltrated into Mo2C-coated graphite matrix without external pressure. The strong interfacial bonding between copper and the graphite matrix was obtained by utilizing the mechanical interlocking within the space limitations of the graphite network. The Mo2C-modified graphite–copper samples resulted to have the average shear strength of 17±4MPa. [Copyright &y& Elsevier]

• CoNi alloy encapsulated in N-doped thin graphene shell was synthesized from MOF. • One-pot cellulose conversion to γ-valerolactone using formic acid as hydrogen donor. • γ-Valerolactone yield reached as high as 55.9 % over AgPW/CoNi@NG. • Reaction mechanism of formic acid as hydrogen donor was revealed over CoNi@NG400. One-step efficient conversion of cellulose into value-added γ-valerolactone (GVL) is of great interest because it not only integrates complex tandem reactions in one-step, but also does not need additional hydrogen sources. To achieve this goal, it is crucial to fabricate high-performance catalyst that can accelerate both hydrolysis of cellulose and further transformation of generated stoichiometric levulinic acid (LA) and formic acid (FA) into GVL. CoNi nanoparticles encapsulated in N-doped thin graphene shell gave GVL yield as high as 55.9 % at 200 °C combined with Ag+-exchanged heteropolyacid (AgPW). This composite catalyst is highly resistant to the corrosion of LA and FA, and hence shows high catalytic stability. LA-adsorption FTIR spectra and DFT calculations indicate that LA and FA can penetrate through shell graphene layers into core CoNi sites via cracks. Compared to H 2 , FA can much more rapidly reduce LA because of its low dissociation energy barrier and high dissociation rate. [ABSTRACT FROM AUTHOR]

Shape-memory polymers are a class of materials that show dual or multi-shape competence. Here a solvent casting method was used to prepare composite films from Cu-BTC crystals in poly (l -lactide) (PLLA) to induce crystallization leading to a marked shape memory effect (SME). Extensive physico-chemical characterizations including solid-state NMR indicated that Cu-BTC triggered the crystallization of PLLA for ensuring the entropy needed for the shape memory behavior. The diffusion of polymeric chains inside pores of activated Cu-BTCs ensured interactions which increases the crystallinity as both simulation and experimental results show. Moreover, the segregation of Cu-BTC crystallites to small copper oxide particles due to the activation increases the volume of the crystalline region observed by microscopic images. We compared the identical features of composite prepared in the same method in where small molecule was encapsulated inside Cu-BTC with PLLA/5 wt% Cu-BTC; we were able to show that having the sharp transition of elastic to rubbery state in the vicinity of cold crystallization temperature in PLLA/5 wt% Cu-BTC provides Cu-BTC crystallites to act as netpoints. Moreover, the reinforcement accompanied by increased toughness demonstrates the combination of improved mechanical properties as well as SME of polymers which rarely have attained. Image 1 [ABSTRACT FROM AUTHOR]