Aerodynamic effects of nearly uniform slipstreams on thin wings in the transonic regime

A simplified model is used to describe the interaction between a propeller slipstream and a wing in the transonic regime. The undisturbed slipstream boundary is assumed to coincide with an infinite circular cylinder. The undisturbed slipstream velocity is rotational and is a function of the radius only. In general, the velocity perturbation caused by introducing a wing into the slipstream is also rotational. By making small disturbance assumptions, however, the perturbation velocity becomes nearly potential, and an approximation for the flow is obtained by solving a potential equation

Role assigning and taking in cloud computing

The widespread use of cloud computing (CC) has brought to the forefront information technology (IT) governance issues, rendering the lack of expertise in handling CC-based IT controls a major challenge for business enterprises and other societal organizations. In the cloud-computing context, this study identifies and ranks the determinants of role assigning and taking by IT people. The study’s integrative research links CC and IT governance to humane arrangements, as it validates and ranks role assigning and taking components through in-depth interviews with twelve IT decision-makers and forty-four Information Systems Audit and Control Association (ISACA) members, engaged as panelists in a Delphi technique implementation. The empirical results recognize skills and competencies as prioritized determinants of IT controls, while IT security, risk and compliance emerge as capabilities crucial to evaluate and manage CC service providers. Despite the study’s generalizability limitations, its findings highlight future research paths and provide practical guidelines toward the high technology of open-market IT self-governance. The latter entails the humane flows of collegial control and responsibility, as opposed to the inhumane flows of authority and power, under the sequestered technique of the bureaucratically-hierarchized IT hetero-governanc

Modification of erbium photoluminescence decay rate due to ITO layers on thin films of SiO2:Er doped with Si-nanoclusters

International audienceDuring the fabrication of MOS light emitting devices, the thin film of active material is usually characterized by photoluminescence measurements before electrical contacts are deposited. However, the presence of a conductive contact layer can alter the luminescent properties of the active material. The local optical density of states changes due to the proximity of luminescent species to the interface with the conductive medium (the top electrode), and this modifies the radiative rate of luminescent centers within the active layer. In this paper we report enhancement of the observed erbium photoluminescence rate after deposition of indium tin oxide contacts on thin films of SiO 2 :Er containing silicon nanoclusters, and relate this to Purcell enhancement of the erbium radiative rate

Relationships between selectivity of Aphis gossypii Glover and Aphis craccivora Koch to sucrose and maltose and their resistance to pirimicarb

Pirimicarb LC50 base line was determined by the dipping technique in successive concentrations of the trade form of pirimicarb in water. The LC25 was used for the selection every month through a year. In case of 10 sucrose solutions versus water, 8 counts indicated that aphids did not prefer the sucrose solution. After 6 hours the cotton aphid could not discriminate between the sugar solution and water. The discrimination between sugars was enhanced by adding 10% maltose. It was observed that the dark forms of the cotton aphid, A. gossypii and light forms of the cowpea aphid, A. craccivora attracted to the higher sucrose solution than the other forms. The cotton aphid, A. gossypii has a light color as the basic color, transforming under reversible condition to dark green, whereas, the basic color of cowpea aphid, A. craccivora usually black in color, transforming under stress to light brownish. This reversed evidence explained the differences in response towards sugar of the two aphid species.It may be concluded that the dark morphs of A. gossypii, and light morphs of A. craccivora which are considered pirimicarb resistant preferred high sugar levels. In other meaning, the present study proved that dark morphs of the cotton aphid and light forms of the cowpea aphid were resistant to pirimicarb and this resistance was positively correlated with the levels of sugars in the plants. Therefore, plant breeders are requested to pay efforts in screening process of resistant plants to produce plants with low sugar contents to increase the effectiveness of pirimicarb against both species of aphids. 

Integrating dual antennas with hybrid DC32-QAM modulation to increase the coverage area for wireless sensor networks

WSN’s and WPAN technologies continue to develop rapidly with integration into numerous applications. The ever increasing demands on these systems require that radio transceiver extended their coverage area and adopt more efficient algorithms to full fill the requirements of new applications. In this paper, a unique application of Multiple Input Multiple Output (MIMO) technology is applied to the application of WSN’s in order to dynamically extend range and thus overall coverage area. The scheme incorporates multiple antennas with Dual Circular 32-QAM modulation for MB-OFDM based systems in order to increase the wireless communication range. Simulation results are then presented that have shown a significant improvement in the system performance in terms of the bit error rate and also signal to noise power rati

Toroidal MHD equilibria and classical diffusion in complex magnetic configurations

Ideal MHD equilibrium for toroidal plasma situated in a magnetic field with single non-planar magnetic axis with variable torsion and curvature is investigated. The plasma is taken to have a non-circular cross section (elliptically or triangularly deformed) through which a longitudinal current with a flat profile flows. Equilibria of the Tokamak or French Harmonica types are examined as special cases of the general class and it is shown that for a given longitudinal current and torsion of the magnetic axis the effect of triangular deformation on the limiting value of beta (the ratio of kinetic to magnetic pressure) is weak and can be neglected. Vertically elongated elliptical deformation of the plasma cross section is shown to lead to an increase in the limiting value of beta relative to that of a circular cross section. Moreover, classical diffusion of non-axisymmetric toroidal plasma is examined with the result that vertical elongation tends to decrease diffusion while triangular deformation appears to show an effect only at high beta .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48947/2/ppv17i12p1049.pd

Toroidal MHD stability in complex magnetic configurations

Mercier's localized perturbation criterion near the magnetic axis is examined for a particular type of toroidal configuration of non-planar magnetic axis of variable curvature and torsion with non-circular (elliptically and triangularly deformed) plasma cross section for the 'resonance case'. As an application, a numerical calculation is carried out for a class of equilibria that belongs to the above configuration with constant torsion. In the absence of longitudinal current, it is possible to have a domain of stability in a system with a horizontally elliptical (and triangular) deformation with an ellipticity corresponding to (a=2b) i.e. the minor axis is twice the major axis. In the presence of a longitudinal current, a domain of stability is also possible and it depends on the direction of the current. Horizontally elliptical and triangular deformations are favourable for stability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48949/2/ppv19i10p969.pd

Dialyzer reuse; effect on efficiency and biocompatibility

Fifteen patients on maintenance haemodialysis were studied before and after reuse of cuprophane hollow-fiber dialysers to assess its biocompatibility and efficiency.There was a significant increase in hematocrit value and hemoglobin level by the end of dialysis. Also, there was a significant decrease in total leukocyte (neutrophilic & eosinophilic) and platelet counts with a peak at 15 minutes after the start of dialysis, then there was a gradual increase till the end of dialysis reaching near the predialysis value.These changes occurred both in the first use and the reuse sessions. The decrease in the neutrophilic count with the reused dialyzer was significantly less compaired to first use dialyzer. The terminal complement complex (TCC) significantly increased and reached its maximum after 15 minutes, then it began to decline till the end of the dialysis. Similarly, these changes were significantly less in the reuse dialyzers. No correlation was found between the changes of the TCC and the decrease in different cellular elements.There was an increase in plasma bicarbonate and pH by the end of dialysis. Also,  hypoxia and hypocapnea occured shortly after the start of dialysis session with acetate dialysate, but they returned to their predialysis values at the end of both dialysis sessions. This can be attributed to the loss of carbon dioxide into the dialysate with subsequent hypoventilation.The clearances of urea, creatinine and phosphorus showed insignificant difference between the new and reused dialyzers at zero and 4hr time with significant decrease by the end of dialysis in both dialysis session. This could  be explained by keeping the surface area of the reused dialyzers within the acceptable values (80-100%) of the first use dialyzer.It can be concluded that reused dialyzers were to some extent more hemocompatible than the first use dialyzers. Complement activation is not the sole factor for the biocompatible reactions during dialysis. Reuse of dialyzers can  be a safe procedure by adopting appropriate sterilization, reprocessing and storage techniques and limited number of reuse

Differentiating between models of Epothilone binding to microtubules using tubulin mutagenesis, cytotoxicity, and molecular modeling

This is the peer reviewed version of the following article: Entwistle, R. A., Rizk, R. S., Cheng, D. M., Lushington, G. H., Himes, R. H., & Gupta, M. L. (2012). Differentiating between models of Epothilone binding to microtubules using tubulin mutagenesis, cytotoxicity, and molecular modeling. ChemMedChem, 7(9), 1580–1586. http://doi.org/10.1002/cmdc.201200286, which has been published in final form at doi.org/10.1002/cmdc.201200286. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Microtubule stabilizers are powerful anti-mitotic compounds and represent a proven cancer treatment strategy. Several classes of compounds in clinical use or trials, such as the taxanes and epothilones, bind to the same region of β-tubulin. Determining how these molecules interact with tubulin and stabilize microtubules is important both for understanding the mechanism of action and enhancing chemotherapeutic potential, e.g. reducing side effects, increasing solubility, and overcoming resistance. Structural studies using nonpolymerized tubulin or stabilized polymers have produced different models of epothilone binding. Here, we used directed mutagenesis of the binding site on Saccharomyces cerevisiae β-tubulin to analyze interactions between Epothilone B and its biologically relevant substrate, dynamic microtubules. Five engineered amino acid changes contributed to a 125-fold increase in Epothilone B cytotoxicity independent of inherent microtubule stability. The mutagenesis of endogenous β-tubulin was done in otherwise isogenic strains. This facilitated the correlation of amino acid substitutions with altered cytotoxicity using molecular mechanics simulations. The results, which are based on the interaction between Epothilone B and dynamic microtubules, most strongly support the binding mode determined by NMR spectroscopy-based studies. This work establishes a system for discriminating between potential binding modes and among various compounds and/or analogues using a sensitive biological activity-based readout