Modelling the bending behaviour of a new hybrid glulam beam reinforced with FRP and ultra-high-performance concrete

The main objective of this research project to develop a new type of hybrid glulam beam that will increase the performance of a timber structural element by combining it with ultra-high-performance concrete with short fibre reinforcement (UHPC-SFR). The hybrid beam is obtained is a layered structures obtained by combining a glued-laminated (glulam) wood beam with UHPC-SFR lamellae that is bonded to its top and bottom faces. The obtained hybrid beam possesses a lower bending stiffness than a glulam beam of similar overall dimensions but has a higher ultimate load capacity. Two models that were developed to validate this concept are presented in this paper. The first is an analytical model based on hypotheses related to the usual strength of materials, and the second is a finite element model. The load–displacement and moment–curvature relationships from both models are compared to the experimental results obtained from the large-scale specimens. The results show good correlation between the analytical modelling and experimental results and illustrate the potential applications of such composite beam configurations for civil engineering structures.     

Do mergers improve hospital productivity?

This paper complements the existing literature on hospital mergers by using data envelopment analysis (DEA) to generate both efficiency and productivity measures to ascertain whether hospital mergers, at least in the short run, result in performance gains. Using data over the period 1996–1998, we apply DEA, both pre-merger and post-merger, to set of hospitals that merged in 1997 as well as to a matching control group of non-merging hospitals over the same timeframe. A comparison of DEA efficiency scores and the Malmquist index values across the case and control hospitals allow us to assess whether any increase in productivity is the result of a merger rather than simply and randomly adding two hospitals' inputs and outputs together.     

Simultaneous δ2H and δ18O analyses of water inclusions in halite with off‐axis integrated cavity output spectroscopy

Stable isotope compositions of ancient halite fluid inclusions have been recognized to be valuable tools for reconstructing past environments. Nevertheless, in order to better understand the genesis of halite deposits, it could be of great interest to combine both δ²H and δ¹⁸O measurements of the water trapped as inclusions in the defects of the mineral lattice. We developed a method combining off‐axis integrated cavity output spectroscopy (OA‐ICOS) connected on line with a modified elemental analyzer (EA‐OA‐ICOS) to perform those measurements. The first step was to test the method with synthetic halite crystals precipitated in the laboratory from isotopically calibrated waters. Water isotopic signatures have been measured with conventional techniques, equilibration for δ¹⁸O and chromium reduction for δ²H. Then, we modified and optimized a conventional EA to connect it online with an OA‐ICOS instrument for H₂O measurements. The technique is first evaluated for calibrated free water samples. The technique is also evaluated for salt matrix effect, accuracy, and linearity for both isotopic signatures. Then, the technique is used to measure simultaneously δ²H and δ¹⁸O values of halite water inclusions precipitated from the evaporation experiments. Data generated with this new technique appeared to be comparable with those inferred from prior off‐line technique studies. The advantages offered by the OA‐ICOS technique are the simultaneous acquisition of both isotopic ratios and the substantial reduction of data acquisition time and sample aliquot size. Natural halite samples have been analyzed with this method. Natural halite samples as old as Precambrian have also been analyzed with this method.     

Non-hydrolytic sol–gel synthesis of polypropylene/TiO2 composites by reactive extrusion

Journal of Sol-Gel Science and Technology - An original way to synthesise polypropylene/titanium dioxide (PP/TiO2) composites combining non-hydrolytic sol–gel chemistry and reactive extrusion...     

Effects of Hexane on Protein Profile,Solubility and Foaming Properties of Defatted Proteins Extracted from Tenebrio molitor Larvae

Inclusion of edible insects in human diets is increasingly promoted as a sustainable source of proteins with high nutritional value. While consumer acceptability remains the main challenge to their integration into Western food culture, the use of edible insects as meal and protein concentrate could decrease neophobia. The defatting of edible insects, mostly done with hexane, is the first step in producing protein ingredients. However, its impact on protein profiles and techno-functionality is still unclear. Consequently, this study compares the protein profiles of hexane-defatted and non-hexane-defatted yellow mealworm (Tenebrio molitor) meals and protein extracts, and evaluates the impact of hexane on protein solubility and foaming properties. Results showed that profiles for major proteins were similar between hexane-defatted and non-defatted samples, however some specific content differences (e.g., hexamerin 2) were observed and characterized using proteomic tools. Protein solubility was markedly lower for T. molitor meals compared to protein extracts. A large increase in the foaming capacity was observed for defatted fractions, whereas foam stability decreased similarly in all fractions. Consequently, although the hexane-defatting step was largely studied to produce edible insect protein ingredients, it is necessary to precisely understand its impact on their techno-functional properties for the development of food formulations.     

Well-defined surface imido amido tantalum(v) species from ammonia and silica-supported tantalum hydrides

The MCM-41 supported hydrides [([triple bond]SiO)(2)TaH(3)], 1a, and [([triple bond]SiO)(2)TaH(3)], 1b, cleave N-H bonds of ammonia at room temperature to yield the well-defined imido amido surface complexes [([triple bond]SiO)(2)Ta(NH)(NH(2))], 2, and 2xNH(3). Additionally, the surface silanes [[triple bond]Si-H] that exist in close proximity to 1a and 1b also react with ammonia at room temperature to give the surface silylamido [Si-NH(2)]. Such reaction is tantalum assisted: surface silanes were synthesized independently and in absence of tantalum by reaction of highly strained silica, SiO(2-1000), with SiH(4) and no reaction with ammonia was observed. Surface-supported complexes 2, 2xNH(3), and [[triple bond]Si-NH(2)] have been characterized by, inter alia, solid-state NMR, IR, and EXAFS and independent synthesis of [[triple bond]Si-NH(2)]. The NMR studies on the fully 15N-labeled samples have led to unambiguous discrimination between imido, amido, and amino resonances of 2*, 2*x(15)NH(3), and [[triple bond]Si-15NH(2)] through the combination of solid-state magic angle spinning (MAS), heteronuclear correlation (HETCOR), 2D proton double-quantum (DQ) single-quantum (SQ) correlation, and 2D proton triple-quantum (TQ) single-quantum (SQ) correlation spectra. The in situ IR monitoring of the reaction of 1a and 1b with regular NH(3) and 15NH(3), and after H/D exchange has yielded the determination of all the NH(x) vibration and deformation modes, with their respective H/D and 14N/15N isotopic shifts. EXAFS study yielded the bond distances in 2 of 1.79(2) Angstrom for Ta=N, 1.89(1) Angstrom for Ta-O, and 1.98(2) Angstrom for Ta-N.     

Combinatorial generation and replication-directed assembly of complex and varied geometries with thin films of diblock copolymers

Directed assembly of fine-scale, very complex patterns with a variety of features, including terminations, jogs, disclinations, acute and obtuse bends, and sharp radii of curvature, was achieved with a symmetric poly(styrene-block-methylmethacrylate) (PS-b-PMMA) copolymer. The complex pattern was generated spontaneously by spin coating and annealing a thin film of a lamellae-forming block copolymer on a chemically neutral surface. The resulting "fingerprint" pattern had a domain spacing of 47.5 nm. Oxygen plasma treatment of the block copolymer converted it into an insoluble chemical nanopattern that was quantified by XPS, goniometry, and the wetting behavior of the block copolymer. Spin coating a second thin film of the block copolymer and annealing resulted in directed assembly that replicated the fingerprint pattern, including the most complicated defect structures. A computer vision algorithm was developed and implemented to compare the patterns quantitatively, taking into account inherent differences in image contrast, scale, rotation, and translation.     

SEC with UV and ELSD detection for analysis of gamma-irradiated PS-radiation-grafted P(VDF/HFP) films

Summary Thin poly(vinylidene fluoride/hexafluoropropylene) (P(VDF/HFP)) films ahve been irradiated with gammarays to induce the initiation of styrene grafting by the indirect method. To obtain a better understanding of the radiation-grafting process we have used size exclusion chromatography (SEC) to study the effect of irradiation of this polymer and the evolution of the molecular weights of the polystyrene (PS) grafted chains as a function of the grafting time. Pristine, irradiated and PS radiation-grafted samples have been compared. We present evidence that the gamma irradiation induces both scission and crosslinking of the P(VDF/HFP) chains. We show that the average molecular weights of the PS grafted chains increase with grafting time and that the asymmetry of the chromatographic peak increases also. These grafted chains have molecular weights much higher than those of pristine P(VDF/HFP) and they cannot be confused with PS homopolymer chains, which have higher molecular weights as both, pristine and radiation-grafted P (VDF/HFP). Reversed-phase high-performance liquid chromatography (RPHPLC) has shown the absence of additives in pristine P(VDF/HFP) and has provided evidence of the presence of oligomers.     

Identifying Major Drivers of Antioxidant Activities in Complex Polyphenol Mixtures from Grape Canes

Grape canes represent a valuable source of numerous polyphenols with antioxidant properties, whose compositions vary depending on the genotype and environmental factors. Antioxidant activities of pure molecules are often reported without considering possible interactions that may occur in complex polyphenol mixture. Using UPLC-MS-based metabolomics and unsupervised classification, we explored the polyphenol variations in grape cane extracts from a collection of European varieties. Antioxidant activities were assessed using ORAC, ABTS, DPPH, FRAP, CUPRAC and chelation assays. Pairwise correlations between polyphenols and antioxidant capacities were performed to identify molecules that contributed more to the antioxidant capacities within a complex mixture of polyphenols.