UNICORE 6 — Recent and Future Advancements

UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments.     

Catalytic desulphurization of benzothiophene in an emulsion via in situ generated H2

Catalytic desulphurization of benzothiophene (BTH) in a water/toluene emulsion, a model system for heavy oil emulsions, was achieved at 340°C using a water-soluble phosphomolybdic acid (PMA), a precursor for dispersed Mo catalyst. This process is based on the activation of H₂O to generate H₂ in situ via the water gas shift reaction (WGSR) for hydrodesulphurization (HDS). At 340°C with an initial CO loading of 4.14 MPa, essentially complete sulphur removal was obtained. Kinetic expressions for the WGSR and HDS of BTH with in situ generated H₂ and externally supplied H₂ were developed and verified experimentally. The kinetic analysis indicates that WGSR is rate-determining and desulphurization with in situ generated H₂ is a relatively fast step. Apparently, in situ H₂ is about seven times more active than externally supplied H₂ for the hydrogenation of BTH. A mechanism for desulphurization involving initial hydrogenation of BTH to dihydrobenzothiophene (DHBTH) followed by hydrogenolysis to give ethylbenzene (EB) and H₂S is proposed.     

Stability preservation analysis in direct discretization of fractional order transfer functions

In this paper, a class of the direct methods for discretization of fractional order transfer functions is studied in the sense of stability preservation. The stability boundary curve is exactly determined for these discretization methods. Having this boundary helps us to recognize whether the original system and its discretized model are the same in the sense of stability. Finally, some illustrative examples are presented to evaluate achievements of the paper.     

Study the effect of distribution of density of states on the depletion width of organic Schottky contacts

Organic semiconductor to metal Schottky contacts have been widely used in electronic devices and to investigate the properties of organic semiconductors. In designing and characterizing these devices the full depletion approximation is used. The analytical and numerical simulations presented in this paper suggest that this approximation is not generally valid. Simulations of a Schottky contact between regioregular-poly 3 hexylthiophene (rr-P3HT) and aluminum show that this approximation becomes worse as molecular order decreases, with the potential profile increasingly deviating from the expected quadratic function of position. Also the depletion width decreasing well below that predicted using the approximation. In this work the slope of the band tail is used as a measure of disorder.     

Calculation of multicomponent vapor–liquid critical point using the Dividing Rectangles global optimization algorithm

In this paper, the Dividing Rectangles (D.R.) global optimization technique is used to predict the critical temperature and pressure for multicomponent systems. The D.R. optimization algorithm is a fast and reliable optimization method without any need for adjustable parameters, initial guesses or objective function derivation. For calculating the critical point the tangent plane distance (TPD) in terms of the Helmholtz energy is selected. The Peng Robinson (PR) equation of state is applied for determining thermodynamic relations. The procedure of the critical point calculation by means of global optimization is described stepwise in order to clarify the concept and method of programing. The D.R.-based computer program is tested for some multicomponent systems and the results are compared with the Simulated Annealing (SA) global optimization method and with experimental data. The results indicated that the number of the objective function calls (the main parameter that increases the speed and efficiency of an optimization algorithm) is reduced to one twentieth with almost the same accuracy.     

Laparoscopy for the impalpable testes. Initial experience of one center

Endoscopic treatment of acute pancreatitis has been proposed in different conditions: acute biliary pancreatitis, pancreatitis related to pancreas divisum or in case of pseudocysts. The efficacy of such endoscopic procedure is discussed.     

Development of artificial neural networks for real time, in situ ellipsometry data reduction

Development of real time in situ monitoring and control of thin film depositions using ellipsometry requires both data acquisition and processing to be rapid. Present speeds of measurement and computation of basic parameters, Ψ and Δ, are sufficient for data acquisition which is essentially real time. However, computation of film parameters, such as thickness and optical properties, generally cannot keep up with the incoming data and must be performed in a batch mode after the deposition.

This work describes the development of enhanced, high speed data reduction algorithms using artificial neural networks (ANN). The networks are trained using computed data and subsequently give values of film parameters in the millisecond time regime. The ANN outputs are used as initial estimates in a variably damped least squares algorithm for accuracy improvement. The combination of these two algorithms provides very accurate solutions in 75 ms per point on a DEC VAX 8800 multiprocessor system running at a combined 12 Mips. This speed is suitable for real time film monitoring and control for growth rates up to 10 nm per second. Results for fixed angle of incidence, single wavelength, in situ data for Ni deposited on BK7 substrates are presented.     

A kinetic study on the reduction of manganese III in presence of citric acid

The rate of reduction of manganese III stabilised by citric acid under variable conditions of Mn(III) concentration, ionic strength, pH and temperature in buffered media was found to obey a second order rate equation, first order with respect to Mn(III) autocatalysed by Mn(II). The reduction was found to proceed to an equilibrium value. The observed rate constants were found to follow a linear relationship with hydrogen ion concentration. Interpretation of results is based on the assumption that there are two reducible species in equilibrium; the aquocomplex and its hydrolysed form. A reaction mechanism is proposed to account for the experimental results. The overall energy (ΔE) and entropy (ΔS) of activation are compared with those for the reduction of Mn(III) in presence of other organic substrates.