Elastic–plastic stress analysis of an orthotropic rotating disc

In this study, the elastic–plastic stress analysis of a curvilinearly orthotropic rotating annular disc is investigated analytically for strain-hardening material behavior. To be able to see the separation of the plastic region, a few angular velocities are taken into consideration for such an analysis. Radial and circumferential stress components are obtained to increase angular velocity. It is seen that the magnitudes of the circumferential stress components are higher than those of the radial stress components. The magnitudes of the residual stress component of the circumferential stress and plastic flow are the highest at the inner surface. The radial displacements in both the elastic and plastic solutions calculated analytically have higher values at the inner surface than those of the outer surface for all the angular velocities.     

EFFECT OF MASS FLUX AND SYSTEM PRESSURE ON TWO-PHASE FRICTION MULTIPLIER

A horizontal boiling water loop was used to obtain pressure drop and heat transfer data for two-phase steam-water flow for pressures of up to 825 kPa. The data were used to examine the predictions of the separated flow model using the Lockhart-Martinelli method of estimating the two-phase friction multiplier.

The influence of mass flux on the two-phase friction multiplier has been reported for high pressure systems by many workers. The present work confirms the existence of this influence at low pressures as well. System pressure is also found to be a parameter. A correlation for the two-phase friction multiplier, incorporating the effects of mass flux and pressure, is presented here. The correlation has been tested against data from two independent sources. The predictions have been found to be in very good agreement with the data.     

DATABASE FOR ORGANIC SULFUR COMPOUNDS USING GC-SCD METHOD. DETERMINATION OF SULFUR CONTAINING COMPOUNDS IN STRAIGHT RUN GAS OBLS (SRGO)

Sulfur standards were studied on a high resolution gas chromatograph (GC) “HP 5890 series II plus ”. Retention times were determined for each individual compound, A sample of straight run gas-oil (SRGO) was analyzed by coulomax method for total sulfur and by GC equipped with sulfur chemiluminescence detector (SCD) for individual sulfur identification, A database for about 165 sulfur compounds was established. Using relationship between total sulfur contents determined by coulomax method and sura of individual sulfur compounds determined by GC-SCD the quantity of different sulfur compounds in SRGO was determined     

Layout optimization of trusses using improved GA methodologies

Summary The main concern of the paper is the simultaneous treatment of size, shape and topology variables in the optimum design of space trusses. As compared to only size optimization, this is a challenging, more difficult and complex problem. The paper discusses a solution algorithm which is based on the use of GAs. Two new methodologies, annealing perturbation and adaptive reduction of the design space, are introduced in conjunction with GAs, bringing additional increase in computational efficeiency. Some common problems in handling shape and topology design considerations are eliminated, which in turn provides a large and a flexible design environment. A numerical problem is presented to test the performance of the proposed methodologies and to compare the results with those existing in the literature. Furthermore, the paper studies a second problem designed to observe the efficiency of GAs in a considerably large and complex design space.     

Effects of interface style on user perceptions and behavioral intention to use computer systems

This study examines the influence of two interface styles (menu- and command-based) on the perceived ease of use, perceived usefulness, and behavioral intention of the user to use the system. We have treated the system interface style as an external factor in the technology acceptance model (TAM) to examine its direct and indirect effects on behavioral intention to accept and use a system. The results showed that the interface style had direct effects on perceived ease of use and perceived usefulness which, in turn, demonstrated significant effects on behavioral intention to use the system. Further, the results showed that perceptions of the menu-based interface were more favorable than perceptions of the command-based interface. These results provide several theoretical and practical implications for designing an effective system.     

A CMOS DCO design using delay programmable differential latches and a novel digital control scheme

A novel 16-bit CMOS digitally controlled oscillator (DCO) is described. This CMOS DCO design is based on a delay programmable differential latch and a novel digital control scheme which yields improved phase noise characteristics. Simulations of a 4-stage CMOS DCO using the 0.5 μm Agilent CMOS process parameters achieved a controllable frequency range of 750 MHz–1.6 GHz with a monotone tuning range of around 1 GHz. Monte Carlo simulations indicate that the time-period jitter due to random supply voltage fluctuations is under 250 ps for worst-case considerations. Also, phase noise was found to be in the range of −175 dBc at a frequency of 600 KHz from the carrier at 1.5 GHz (for digital control word of 1512 H) after numerous iterations of Monte Carlo simulations. FFT analysis indicate a total harmonic distortion (THD) of around − 57 dB for the DCO output signal. This CMOS design would thus provide considerable performance enhancement in digital PLL applications.     

Numerische Strömungssimulation an einer Niedergeschwindigkeits-Axialturbine unterschiedlichen Deckband-Abschirmungen des Laufrades

The numerical simulation of the flow through a low-speed turbine stage followed by a vane row is presented for two experimentally investigated shrouds of different weight and shape. The aerofoil-pressure distribution of the blades and vanes as well as the flow at the exit of the bladerow is compared in the experimentally and numerically obtained results. In addition to experimental data published earlier, numerical flow results are added, which had been inaccessible in the experiment. The choice of the turbulence model influences substantially the result of the numerical simulation for the flow leaving the rotor blade row. Furthermore the computational result shows the influence of the flow pattern in the labyrinth cavity on the power loss. The prediction of the static pressure decrease along the flow path through the seal across the cavities concludes this investigation.     

Retrieving relevant time‐course experiments: a study on Arabidopsis microarrays

Understanding time‐course regulation of genes in response to a stimulus is a major concern in current systems biology. The problem is usually approached by computational methods to model the gene behaviour or its networked interactions with the others by a set of latent parameters. The model parameters can be estimated through a meta‐analysis of available data obtained from other relevant experiments. The key question here is how to find the relevant experiments which are potentially useful in analysing current data. In this study, the authors address this problem in the context of time‐course gene expression experiments from an information retrieval perspective. To this end, they introduce a computational framework that takes a time‐course experiment as a query and reports a list of relevant experiments retrieved from a given repository. These retrieved experiments can then be used to associate the environmental factors of query experiment with the findings previously reported. The model is tested using a set of time‐course Arabidopsis microarrays. The experimental results show that relevant experiments can be successfully retrieved based on content similarity.Inspec keywords: botany, lab‐on‐a‐chip, genetics, bioinformatics, information retrieval, data mining, data analysis, associative processingOther keywords: relevant time‐course experiment retrieval, time‐course Arabidopsis microarray, time‐course gene regulation, stimulus response, systems biology, computational method, gene behaviour model, gene networked interaction, latent parameter, model parameter estimation, meta‐analysis, data analysis, time‐course gene expression experiment, information retrieval, computational framework, time‐course experiment query, relevant experiment list, repository, environmental factor, query experiment, experimental content similarity