The use of ultra- and nanofiltration techniques in homogeneous catalyst recycling

In recent years, the application of membrane technology in homogeneous catalyst recycling has received widespread attention. This technology offers a solution for the major drawback of homogeneous catalysis, that is, recycling of the catalyst. From both an environmental and an industrial point of view, this technology is very interesting, since it allows the future application of homogeneous catalysts in the synthesis of commercial products, leading to faster, cleaner and highly selective green industrial processes. In this account, an overview is given of the promising results obtained in the field of homogeneous catalyst recycling using nanofiltration membrane technology.     

Refined electrical analysis of two charge states transition characteristic of “borderless” silicon nitride

In this paper we evaluate the electrical properties of silicon nitride so called “borderless nitride” deposited by PECVD process in the pre metal dielectric stack. Thus metal/silicon nitride/semiconductor structures have been analysed by an original electrical characterization based on C(V) and I(V) hysteresises. The objective is to understand how this material, initially introduced as etch stop layer and contaminant diffusion barrier, can impact active device performances. It appears that silicon nitride contains a huge defect quantity characterized in a non steady state and strongly influenced by maximum voltage applied. These charges can be balanced between either positive and negative states and are suspected to be K centers defects existing under two paramagnetic states K⁺ and K⁻. In addition, a RF power variation of SiH₄/NH₃ ratio, giving refractive indexes from 1.94 to 2.77, have shown that flatband voltage shift decreases with [Si]/[N] ratio whereas leakage current increases.     

Méthode numérique utilisée dans le cadre ďapplications du principe ďéquivalence en électromagnétisme

Kottler’s formula is difficult to calculate when it is applied to regular surfaces of low curvature, that is when the main radius of curvature are small compared with the free wavelength. To correct the calculated field aberration we suggest the use of a correction normalized diffraction term which is applied to the differential surface. This term is the geometrical mean of the two soft and hard electromagnetic coefficients used in geometric theory of diffraction. The method has been tested with efficiency for spheres, cones and spheroids, and could be used to study the influence of a radome on the radioelectric behaviour of an antenna located inside it.     

Behavioral responsiveness of adrenalectomized, hypophysectomized, and intact rats to electric shock.

Tested whether the altered rates of acquisition and extinction of avoidance behavior in adrenalectomized and hypophysectomized rats are associated with abnormal responsiveness to electric shock. The electrical threshold for flinch, jump, and vocalization behaviors in adrenalectomized and hypophysectomized Ss (N = 95) was measured in 2 experiments. Adrenalectomized Ss had higher thresholds for flinch and jump responses than hypophysectomized Ss, and also a higher flinch threshold than weight-matched controls. Hypophysectomized Ss had normal thresholds for all 3 behaviors. The difference in threshold for the flinch response between adrenalectomized and hypophysectomized or normal Ss was not explained by differences in body weight, although heavy Ss responded less to electric shock than light Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring and enhancing the home experience

This paper describes extensive user studies that have been conducted to understand what "home" actually means to people, and to find out how people would like to live in their "dream home." Based on these studies, three innovative user-system interaction concepts were developed that help to enhance people's home experience. Electronic Publication     

Aqueous solutions of uranium(VI) as studied by time-resolved emission spectroscopy: a round-robin test

Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO2(2+)aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.     

Quantum technology: the second quantum revolution

We are currently in the midst of a second quantum revolution. The first quantum revolution gave us new rules that govern physical reality. The second quantum revolution will take these rules and use them to develop new technologies. In this review we discuss the principles upon which quantum technology is based and the tools required to develop it. We discuss a number of examples of research programs that could deliver quantum technologies in coming decades including: quantum information technology, quantum electromechanical systems, coherent quantum electronics, quantum optics and coherent matter technology.     

Flow-induced enhancement of concentration fluctuations in polymer mixtures

Many mixtures of high-molecular-weight polymers are partially miscible, separating into two co-existing phases in some ranges of temperature and concentration. Generally these binary blends exhibit lower critical solution temperature (LCST) behaviour, becoming phase separated as the temperature is raised. We have been undertaking a systematic study of the effect of simple shear flow on the miscibility limits of a number of high-molecular-weight binary polymer blends exhibiting lower critical-solution temperatures. Using a parallel-plate shear cell and light-scattering detection, we have observed large shifts in the cloud-point curves as blends are heated while shear is applied, and we have been able to show, using ancillary measurements of glass-transition temperatures on quenched samples, that these effects are the results of changes in the miscibility of the blends and not artefacts of the scattering techniques. Both shear-induced 'mixing' and 'demixing' have been observed-the latter in temperature ranges well below the quiescent cloud points. We have investigated the kinetics of the appearance of the two-phase structures, and this is very reminiscent of the spinodal decomposition processes observed in zero shear from these blends. Small-angle neutron scattering is very sensitive to the rather short wavelength concentration fluctuations (a few nanometres) in binary systems, both in the stable one-phase region and in the early stages of instability in the two-phase region. Small-angle neutron-scattering results on blends sheared and quenched at temperatures far below the spinodal temperature show the effects of the shear in modifying the blend's structure factors.     

Experimental protocol to determine the ability of PET to crystallise

PET [poly(ethylene terephtalate)] is a semi-crystalline thermoplastic that is very suitable for forming processes and is widely used in various technologies. For specific applications, it is necessary to avoid the crystallization of the material by quenching from the melting state while for other applications this crystallization is required. It follows that the ability of PET to crystallize could be a crucial industrial problem, particularly because of the large range of PET proposed by plastic suppliers. This work deals with a calorimetric method able to discriminate this aptitude between various PET rapidly and to give a criterion of crystallizability.