Glass formation, optical properties and local atomic arrangement of chalcogenide systems GeTe-Cu and GeTe-In

Glass-forming regions of ternary Ge-Te-Cu and Ge-Te-In chalcogenide glasses are examined by differential scanning calorimeter and by X-ray diffraction. Glass transition and crystallization temperatures are about 120 °C To 260 °C, respectively higher than those of binary Ge-Te glass [T. Katsuyama and M. Matsumura, Infrared Optical Fibres (Adam Hilger, London, 1989) p. 212]. Only a small range of compositions after quenching the melting alloy is characterized by disordered state, but this range of composition is widened when using a vapor deposition technique. These compositions have two glass transition temperatures, showing the existence of phases in the sample. Both the Kissinger equation and modified Kissinger kinetic analysis were adopted to estimate activation energy and the reaction order of the process. Ge-Te-Cu and Ge-Te-In crystallized in two stages, nucleation and crystal growth. These two processes can be distinguished by exothermal crystallization patterns. An atomic radial distribution analysis has been made on bulk Ge₁Te₄In _x and Ge₁Te₄Cu _x with x = 0.1 by X-ray diffraction techniques. The radial distribution function (RDF) is discussed in terms of the structure factor F(s). Thin films of Ge-Te-Cu and Ge-Te-In are deposited on silicate glass and silicon wafer substrates by vacuum evaporation. The optical energy E _opt are determined from transmission and reflection data of a deposited films. The value of E _opt decreased by increasing metal additive such as Cu or In and discussed as a function of the conditions of their preparation such as substrate type.     

Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD

Nanocrystalline diamond (NCD) films with a thickness of ~ 6 µm and average grain sizes ranging from 60 to 9 nm were deposited on silicon wafers using a hot-filament chemical vapor deposition (HFCVD) process. These samples were then characterized in order to identify correlations between grain size, chemical composition and mechanical properties. The characterization reveals that our films are phase pure and exhibit a relatively smooth surface morphology. The levels of sp²-bonded carbon and hydrogen impurities are low, showing a systematic variation with the grain size. The hydrogen content increases with decreasing grain size, whereas the sp² carbon content decreases with decreasing grain size. The material is weaker than single crystalline diamond, since both stiffness and hardness decrease with the reduction in crystal size. These trends suggest gradual changes in the nature of the grain boundaries, from graphitic in case of 60 nm grain size material to hydrogen terminated sp³ carbon in 9 nm grain size material. The films exhibit low levels of internal stress and free-standing structures with a length of several centimeters could be fabricated without noticeable bending     

Properties of single-walled carbon nanotube-based aerogels as a function of nanotube loading

Here, we present the synthesis and characterization of low-density single-walled carbon nanotube-based aerogels (SWNT-CA). Aerogels with varying nanotube loading (0–55 wt.%) and density (20–350 mg cm^?3) were fabricated and characterized by four-probe method, electron microscopy, Raman spectroscopy and nitrogen porosimetry. Several properties of the SWNT-CAs were highly dependent upon nanotube loading. At nanotube loadings of 55 wt.%, shrinkage of the aerogel monoliths during carbonization and drying was almost completely eliminated. Electrical conductivities are improved by an order of magnitude for the SWNT-CA (55 wt.% nanotubes) compared to those of foams without nanotubes. Surface areas as high as 184 m² g^?1 were achieved for SWNT-CAs with greater than 20 wt.% nanotube loading.     

Elaboration of thin films based on p-tert-butyl-calix [8] arene. Application to the chemical sensors type EIS and ISFET

In this paper we report some results about recognition reagents in an EIS (electrolyte—insulator—semiconductor) and ISFET (ion-sensitive field-effect transistor) type sensors, elaborated with a p-tert-butyl-calix [8] arene molecule. This calixarene was deposited by sublimation onto the surface insulator of the samples. Reflexion—adsorption infrared spectroscopy and X-ray diffraction were performed to characterize the chemical properties and the morphology of the layers. Electrochemical measurements were made to study the sensitivity and the selectivity of this sensitive membrane towards earth alkaline cations and the transition metals. A linear sensitivity was obtained only for the Ca²⁺. These devices exhibit a high chemical stability in liquid media and consequently can be used as sensors.     

Enhanced Solubility of Paracetamol by Various Hydrotropic Agents

The increase in the aqueous solubility of paracetamol by the use of various hydro tropes was studied.

These agents were sodium glycinate, sodium gentisate, sodium salicylate and nicotinamide. All of these agents increased the aqueous solubility to varying degrees, with nicotinamide and sodium salicylate being the most efficient solubilizers.

A conductance parameter was investigated as a mean of aiding interpretation of the solubility data. Dielectric constants could only be determined in the nicotinamide systems.

Ultra-violet spectral analysis, TLC, infra-red, and NMR techniques were utilized in order to elucidate the solubility mechanism. These tests indicate that no special bonding or complex formation exists for the sodium salt hydrotropes in these preliminary work. There is some evidence from UV & TLC analysis that nicotinamide and paracetamol enter into complex formation.

The other hydrotropic agents, in this study indicate the mechanism of solubilization is one of “salting - in” by causing miscibility of two formally immiscible liquid phases of ternary systems.     

New separation method of metal/plastic micronized particles using travelling wave conveyors

The paper reports an experimental investigation for studying the movement dynamics and the separation of micronized particles on a poly-phase travelling wave conveyor (TWC). A digital balance and a sensitive electrometer controlled by Labview software were used to analyse the velocity and the material flow rate on a three-phase conveyor with respect to the variation of both the amplitude and the frequency of the applied voltage. It was found that about 80% of the particles mass move together in one single wave and that the electric charge gained by the particles increases with the intensity of the electric field. Moreover, preliminary experiments showed that it is possible to separate a granular mixture of plastic and copper micronized particles using a TWC. Successful experiments were carried out on micronized samples of both electric cable and electronic card wastes. High purity metal was recovered.     

Preparation of epoxy composites with CTAB‐modified BN and MWCNTs

In this study, multi‐walled carbon nanotubes (MWCNTs) and boron nitride (BN) were functionalized with cetyltrimethylammonium bromide (CTAB) at both pH 5.5 and pH 11. These MWCNT‐CTAB and BN‐CTAB particles used to prepare the composites were dispersed in a bisphenol A (DGEBA)‐type epoxy resin (ER) system at room temperature. The TGA analysis showed that the BN composite can significantly improve the thermal stability of neat ER at temperatures above 400 °C. The curing degrees of the nanocomposites were calculated to be approximately the same values as neat ER using the Beer–Lambert law from FTIR spectra. The best electrical conductivity of the composites obtained was 3.10 × 10⁻³ S/cm for ER/MWCNT‐CTAB (pH 5.5). The surface hardness, Young's modulus, and tensile strength of the composites were examined. The surface hardness values of the ER/MWCNT‐CTAB composites were higher than those of the other composites. The composite morphology was characterized using X‐ray diffraction (XRD) and scanning electron microscopy (SEM). POLYM. COMPOS., 37:3423–3432, 2016. © 2015 Society of Plastics Engineers     

On the design of multi-wavelength copy interconnects with reduced complexity

A multi-wavelength copy interconnect is a switching network capable of replicating a signal arriving at the input on a specific wavelength to one or more outputs possibly on different wavelengths. Such an interconnect can be useful in building optical multicast switches for wavelength division multiplexing (WDM) networks. In this article, we investigate, for the first time, the problem of designing copy networks that can simultaneously multicast input signals to a set of outputs while changing the wavelength of the replica according to the required routing pattern. We propose a novel multi-wavelength crossbar (MWX) switch that can switch an input signal on a specific wavelength to two different output wavelengths. The proposed MWX is used as a building block to construct two classes of multi-log_2N copy networks, namely, baseline and Bene? interconnects. The design space of the proposed interconnect classes is characterized and their hardware complexity is analyzed. We show that the proposed interconnects are transparent to existing multicast routing algorithms, and present simple routing algorithms for routing of multicast requests over the proposed designs. Comparisons with existing designs confirm that the proposed interconnects require a smaller number of space switches and wavelength conversion processes as compared to most conventional copy networks. In particular, for a large number of wavelengths and for any number of fibers the proposed design requires 50% less switching elements as compared to best available designs.     

Physical and chemical characterization of adsorbed protein onto gold electrode functionalized with Tunisian coral and nacre

Bone substitutes are more and more used in bone surgery because of their biologic safety, clinic efficiency and facility to synthesize. Bone substitutes with active osteogenic properties, associating biomaterials with organic macromolecule components of the extracellular matrix (protein, GAG) are recommended. Nevertheless, we should have a simple technique to control interactions between proteins and the material. Natural coral and nacre have been found to be impressive bone graft substitutes. In this work, we characterize nacre and coral powder using energy dispersive X-ray analysis (EDX). We used electrochemical impedance spectroscopy (EIS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to evaluate bovine serum albumin (BSA) as model protein, adsorbed to these biomaterial surfaces. In order to understand the nacre/coral-protein interfacial compatibility, it is necessary to investigate the wettability.     

Energy conservation regulations: Impacts on design and procurement of low energy buildings

To reduce the substantial contribution of the built environment to energy consumption and carbon dioxide emissions, the new ‘Part L: Conservation of Fuel and Power’ of the Building Regulations for England and Wales came into force in April, 2006. As a result, the design of all new-build and refurbished buildings must comply with ‘Target Carbon Emissions Rates’. Apart from the purely practical implications of compliance, the new Part L has prompted interesting questions concerning procurement and the impact on design and construction teams.