Analysis of homogeneous turbulent reacting flows

Full turbulence simulations at low Reynolds numbers were made for the single-step, irreversible, bimolecular reaction between non-premixed reactants in isochoric, decaying homogeneous turbulence. Various initial conditions for the scalar field were used in the simulations to control the initial scalar dissipation length scale, and simulations were also made for temperature-dependent reaction rates and for non-stoichiometric and unequal diffusivity conditions. Joint probability density functions (pdf's), conditional pdf's, and various statistical quantities appearing in the moment equations were computed. Preliminary analysis of the results indicates that compressive strain-rate correlates better than other dynamical quantities with local reaction rate, and the locations of peak reaction rates seem to be insensitive to the scalar field initial conditions

Different models used in Africa and Asia for off grid electrification and the challenges faced

This paper explores the different models used for rural electrification in developing countries. The unsuccessful projects and their causes of failure are analysed and some components of successful projects are also outlined. The analysis proves that there is more to just the technology aspect of the deployment and the socio economic and political factors play a major role in determining success of the programs. The two most successful models for the large scale dissemination of solar systems are this fee-for-service model and the micro-credit scheme

Stakeholder Management Strategies in Infrastructure Megaprojects – A Dimensions of Power Perspective

Infrastructure megaprojects involve managing external stakeholders with diverse interests. The existing governance mechanisms such as contracts and conformance to standards are not possible with these external stakeholders as they are not accountable to the project. There are records of underperformance of megaprojects as they fail to manage the stakeholders who exist across a permeable boundary. While there are instances of various strategies used by the project team in managing these external stakeholders, the relation between strategies and stakeholder category is still unexplored. We argue that the dimensions of power framework can help make sense of the strategies in practice by the project team. Hence, using the case study of a metro rail project in India, we firstly categorize the external stakeholders into stakeholders in land acquisition and stakeholders in existing services. We then unearth the strategies devised by the project team in managing these external stakeholders. The strategies identified from the case are: 1) use of persuasion, 2) coordination by deputation, 3) give and take behavior, 4) enabling design flexibility, and 5) extra work for stakeholders. We then use the dimensions of power framework to explain these strategies and understand the resources available with the project team such as recruitment discretion, government backing and fund discretion. Finally, we explore the link between project team strategies and stakeholder categories. It is observed that the ‘give and take’ strategy works with legal landholders in land acquisition and ‘extra work for stakeholders’ works with stakeholders in existing services who are affected during construction. ‘Enabling design flexibility’ works for all stakeholders who express concern over the proposed design. ‘Coordination by deputation’ works with all government employees across all the categories of external stakeholders

Physio-chemical and antibacterial characteristics of pressure spun nylon nanofibres embedded with functional silver nanoparticles

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Date of Acceptance: 05/06/2015A novel and facile approach to prepare hybrid nanoparticle embedded polymer nanofibers using pressurised gyration is presented. Silver nanoparticles and nylon polymer were used in this work. The polymer solution's physical properties, rotating speed and the working pressure had a significant influence on the fibre diameter and the morphology. Fibres in the range of 60–500 nm were spun using 10 wt.%, 15 wt.% and 20 wt.% nylon solutions and these bead-free fibres were processed under 0.2 MPa and 0.3 MPa working pressure and a rotational speed of 36,000 rpm. 1–4 wt.% of Ag was added to these nylon solutions and in the case of wt.% fibres in the range 50–150 nm were prepared using the same conditions of pressurised gyration. Successful incorporation of the Ag nanoparticles in nylon nanofibres was confirmed by using a combination of advanced microscopical techniques and Raman spectrometry was used to study the bonding characteristics of nylon and the Ag nanoparticles. Inductively coupled plasma mass spectroscopy showed a substantial concentration of Ag ions in the nylon fibre matrix which is essential for producing effective antibacterial properties. Antibacterial activity of the Ag-loaded nanofibres shows higher efficacy than nylon nanofibres for Gram-negative Escherichia coli and Pseudomonas aeruginosa microorganisms, and both Ag nanoparticles and the Ag ions were found to be the reason for enhanced cell death in the bacterial solutionPeer reviewe

Modeling Vacuum Arcs

We are developing a model of vacuum arcs. This model assumes that arcs develop as a result of mechanical failure of the surface due to Coulomb explosions, followed by ionization of fragments by field emission and the development of a small, dense plasma that interacts with the surface primarily through self sputtering and terminates as a unipolar arc capable of producing breakdown sites with high enhancement factors. We have attempted to produce a self consistent picture of triggering, arc evolution and surface damage. We are modeling these mechanisms using Molecular Dynamics (mechanical failure, Coulomb explosions, self sputtering), Particle-In-Cell (PIC) codes (plasma evolution), mesoscale surface thermodynamics (surface evolution), and finite element electrostatic modeling (field enhancements). We can present a variety of numerical results. We identify where our model differs from other descriptions of this phenomenon.Comment: 4 pages, 5 figure

Bioinspired electrohydrodynamic ceramic patterning of curved metallic substrates

Template-assisted electrohydrodynamic atomisation (TAEA) has been used for the first time to pattern curved metallic surfaces. Parallel lines of ceramic titania (TiO2) were produced on titanium substrates, convex and concave with diameters of ~25 mm, at the ambient temperature. Optimal results were obtained with 4 wt% TiO2 in ethanol suspension deposited over 300 s during stable cone-jetting at 20 µl/min, 10kV and collection distance 80 mm. A high degree of control over pattern line width, interline spacing and thickness were achieved. Nanoindentation load-displacement curves were continuous for the full loading and unloading cycle, indicating good adhesion between pattern and substrate. At a loading rate of 1 μN/s and a hold time of 1 s, pattern hardness decreased as load increased up to 7 μN and remained at 0·1 GPa up to higher loads. Elastic modulus behaved similarly, and both were not sensitive to loading rate. The effect of heat treatment to further consolidate the patterned deposits was also investigated. Hardness of the patterns was not markedly affected by heating. This work shows that TAEA is highly controllable and compatible on a range of substrate geometries. Extending TAEA capabilities from flat to curved surfaces, enabling the bioactive patterning of different surface geometries, takes this technology closer to orthopaedic engineering applications

Investigation on the Structural and Optical Properties of Thermally Evaporated Indium Selenide Compound Material for Solar Cell Application

In2Se3 thin films with different thicknesses have been deposited by thermal evaporation method on glass substrate under vacuum pressure of 10-6 Torr. Structural Properties of these films were studied by different analytical techniques. X- ray diffraction revealed as deposited films have amorphous nature and annealing effect enhanced crystalline structure. Structural studies by XRD results showed the polycrystalline nature of the films. The Full Width at Half Maximum (FWHM) values were observed from the XRD pattern and used to evaluate the microstructural parameters like crystallite size, strain, dislocation density. The optical absorption spectra of In2Se3 films were studied in the wavelength region of 250–2500 nm. The optical properties show that the band gap (Eg) values vary from 2.5 to 3.34 eV as an-nealing temperature varies from 150 to 350C. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3513

Simple sequence repeat (SSR) markers for assessing genetic diversity among the parental lines of hybrid rice (Oryza sativa L.)

The present scientific study was carried out at Tamil Nadu Rice Research Institute, Aduthurai with the objective of studying the genetic divergence among 51 restorer and five maintainer lines in terms of grain quality and fertility restorer genes (Rf3, Rf4 and Rf7) using 55 primers of simple sequence repeat (SSR) markers. Among them, 37 SSR markers were found to be polymorphic and the number of amplified fragments ranged from one to five. The highest polymorphic information content (PIC) value (more than 0.60) was observed for eight primers viz., AB 443, RM 3, RM 29, RM 226, RM 228, RM 304, RM 1812 and RM 3873 and average PIC value was 0.444. Cluster analysis using NTSYS generated dendrogram divided all the 56 parental lines into two distinct groups viz., maintainer line (Group I) and restorer line (Group II) at 76% coefficient of similarity. Maintainer line group consisted of five genotypes (COMS 23B, COMS 24B, COMS 25B, CRMS 31B and CRMS 32B) and restorer line group had 51 genotypes. Further, at 80% similarity, all fifty one restorer lines were again grouped into nine clusters. With higher polymorphism revealed by SSR markers, parental lines having the similar genetic background from pedigree information were grouped into different clusters. The combination of pedigree analysis and SSR markers could be a more reliable method to study the diversity and grouping of parental lines of hybrid rice. Hybridization between diverse restorer and CMS groups identified from this study would be expected to yield hybrid combinations with premium grain quality and good fertility restoration.Keywords: Simple sequence repeat (SSR), maintainer and restorer genetic diversity, grain quality, fertility restorationAfrican Journal of Biotechnology Vol. 12(33), pp. 5105-5116

Managing Project Community in Infrastructure Megaprojects

Developing countries, such as India, look towards massive investments in infrastructure megaprojects to achieve their development goals quickly. However, megaprojects are plagued with failures and inefficiencies often due to the project’s inability to handle external stakeholders such as project community. Project communities are the end users of the project, are most inconvenienced by the project, and they hold significant potential to stop the project by asking a democratically elected government to do so. In this context, we seek to understand how a metro rail megaproject in India manages their project community through visible and invisible strategies using an in-depth case study. The organizational power theories of the dimensions of power theory and the circuit of power theory are used to explain these strategies. The research draws on data from 30 semi-structured interviews with the project team and five years of social media data comprising 640 Tweets. A Grounded theory method is used to find the visible, invisible strategies and their relation between each other. The results show that invisible strategies depend on visible strategies by relying on the adaptations made for the community and the visible strategies depend on the invisible strategies by relying on the changed preferences of the project community. The findings have contributions to theory and practice of managing project community in infrastructure megaprojects

Modeling arcs

Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gradient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging