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SelectedWorks

Selected Works

2008

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Articles 1 - 14 of 14

Full-Text Articles in Nanoscience and Nanotechnology

Leading Firms As Knowledge Gatekeepers In A Networked Environment, Deogratias Harorimana Mr Nov 2008

Leading Firms As Knowledge Gatekeepers In A Networked Environment, Deogratias Harorimana Mr

Dr Deogratias Harorimana

This chapter introduces the role of the knowledge gatekeeper as a mechanism by which knowledge is created and transferred in a networked environment. Knowledge creation and transfer are essential for building a knowledge based economy. The chapter considers obstacles that inhibit this process and argues that leading firms create a shared socio-cultural context that enables the condivision of tacit meanings and codification of knowledge. Leading firms act as gatekeepers of knowledge through the creation of shared virtual platforms. There will be a leading firm that connects several networks of clients and suppliers may not interact directly with one another, but …

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Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova Sep 2008

Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova

Eng-Poh Ng

The main types of nanoporous adsorbents for water are identified and described with emphasis on the mechanism of adsorption, modification, improvement of the water sorption capacity, possible regeneration, and stabilization. Among the three main groups of water sorbents, i.e. inorganic materials (zeolites, clays, silica), carbon based materials and organic polymers, the first one is described in details. The significance of their porosity, chemical and structural features relative to the water adsorptive properties of each inorganic type materials is reviewed. Important features for silicates, zeolites, aluminophosphates, mesoporous materials and clays are described, which define the interactions between the water and the …

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Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala Apr 2008

Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala

Mr Ajaya Kumar Kavala

No abstract provided.

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Nanoclay Reinforced Fibers And Nonwovens, Raghavendra R. Hegde Dr Jan 2008

Nanoclay Reinforced Fibers And Nonwovens, Raghavendra R. Hegde Dr

Raghavendra R Hegde Dr

In this research, polypropylene fibers and nonwoven samples were produced with the commercial samples of nanoclay additives in semi-commercial processing machinery. Influence of two different types of nanoclay additives, at different add on levels on processing, structure and morphology of nonwovens is studied. The WAXD and DSC data showed some change in crystallinity and melting behavior indicating changes in the fiber morphology towards improved mechanical properties. Presence and extent of exfoliation of nanoclay in the polymer was verified using transmission electron microscopy (TEM). TEM image reveals intercalated and exfoliated morphology of nanocomposites. About 10 to 20 % increase in tensile …

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Charge Transfer Mechanisms In Electrospinning, Jonathan J. Stanger Jan 2008

Charge Transfer Mechanisms In Electrospinning, Jonathan J. Stanger

Jonathan J Stanger

Electrospinning is a method of producing nano structured material from a polymer solution or melt using high strength electric fields. It is a process that has yet to find extensive industrial application yet shows promise if obstacles such as low rate of production overcome perhaps by more complete theoretical modelling. This work examines the effects of adding an ionic salt to a solution of poly(vinyl alcohol) in water. The direct effect was an increase the charge density and electric current. It was found that an increase in charge density decreases the mass deposition rate and forms a thinner initial jet. …

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Removal Of Organic Dyes From Industrial Wastewaters Using Uv/H2o2, Uv/H2o2/Fe (Ii), Uv/H2o2/Fe (Iii) Processes (Persian Paper), Mir Saeed Seyed Dorraji Jan 2008

Removal Of Organic Dyes From Industrial Wastewaters Using Uv/H2o2, Uv/H2o2/Fe (Ii), Uv/H2o2/Fe (Iii) Processes (Persian Paper), Mir Saeed Seyed Dorraji

Mir saeed Seyed Dorraji

UV/H2O2, UV/H2O2/Fe (II) and UV/H2O2/Fe (III) processes are very effective in removing pollutants from wastewater and can be used for treatment of dyestuff units wastewaters. In this study, Rhodamine B was used as a typical organic dye. Rhodamine B has found wide applications in wax, leather, and paper industries. The results from this study showed that this dye was degradable in the presence of hydrogen peroxide under UV-C irradiation (30W mercury light) and Photo-Fenton process. The dye was resistant to UV irradiation. In the absence of UV irradiation, the decolorization efficiency was very negligible in the presence of hydrogen. Theeffects …

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Supercritical Water Oxidation Process And Its Application In Treatment Of Industrial Wastewater (Persian Paper), N. Daneshvar, S. Aber, Mir Saeed Seyed Dorraji, M. Zarei, M. H. Rasoulifard Jan 2008

Supercritical Water Oxidation Process And Its Application In Treatment Of Industrial Wastewater (Persian Paper), N. Daneshvar, S. Aber, Mir Saeed Seyed Dorraji, M. Zarei, M. H. Rasoulifard

Mir saeed Seyed Dorraji

In the last two decades, supercritical water has become an interesting medium for chemistry. One of its most investigated applications is the oxidative treatment of aqueous wastes containing organic compound in the so-called “supercritical water oxidation”. In this technology, supercritical water acts as a non-polar solvent. Consequently, even non-polar organic compounds and gases like oxygen become completely miscible with the supercritical fluid. During the supercritical water oxidation (SCWO) process, the organic compounds react completely with oxidant –mostly oxygen- in a single phase reaction forming CO2 and H2O. The hetero-atoms present in the organic wastes are transformed into the mineral acids. …

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Do R&D Programs Of Different Government Levels Overlap In The European Union?, Andrea Fernandez-Ribas, Isabel Busom Jan 2008

Do R&D Programs Of Different Government Levels Overlap In The European Union?, Andrea Fernandez-Ribas, Isabel Busom

Andrea Fernandez-Ribas

Multiple levels of government currently design and implement research and innovation programs both in the US and in Europe. Empirical analysis of interdependencies among programs has not been fully explored, however. Our contribution is a first step in understanding potential complementarities across R&D programs. Using a sample of Spanish manufacturing firms, we study the determinants of firms’ participation in national and in European level research programs and test for differences across programs. Our results suggest that firms’ participation in European and national R&D programs is largely driven by different factors. We interpret these results as suggesting that, ex-post, there is …

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Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes Jan 2008

Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes

João F Gomes

This paper describes the study that led to the development of a carbon dioxide emissions matrix for the Oeiras municipality, one of the largest Portuguese municipalities, located in the metropolitan area of Lisbon. This matrix takes into account the Greenhouse Gases (GHG) Emissions, due an increase of electricity demand in buildings as well as solid and liquid wastes treatment, from the domestic and services sectors. Using emission factors that were calculated from the relationship between the electricity produced and amount of treated wastes, the GHG emissions in the Oeiras municipality, were estimated for a time series of 6 years (1998 …

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Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes Jan 2008

Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes

João F Gomes

CO2 capture from combustion flue gases is currently an issue of main interest due to the high taxes being imposed on industrial companies as a measure to achieve CO2 emissions abatement. CO2 capture can be efficiently achieved by gas absorption using amines, namely Monoethanolamine (MEA). Based on henrys law, validated with previously published experimental work, this study considers the development of a dynamic model of an absorption column for post combustion CO2 capture. A dynamic model of the temperature swing de-absorption process was developed with the integration of both models for absorption and de-absorption (with the introduction of heat exchangers, …

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Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes Jan 2008

Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes

João F Gomes

This paper analyses the current energy balance of Portugal, considering the actual sources which are mainly traditional fossil fuels, hydroelectric power and renewables. Other potential sources are discussed also and taken into consideration in view of the previewed evolution of the country in energetic terms. Among these, nuclear power, once regarded as an option, is now being re-considered. This paper also sums up the main issues to be considered in a future debate on the subject.

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Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle Jan 2008

Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle

Eng-Poh Ng

AlPO-18 layers were prepared on Si wafers via spin-coating or the Langmuir−Blodgett (LB) method using nanosized crystals. Multilayers were deposited by spin-coating, whereas the seeds assembled by the LB technique were monolayers. The seeded layers were not stable upon secondary growth under microwave radiation, and no films were formed on the supports. Dense AlPO-18 films could be obtained by secondary growth after stabilization of the seed layers by adding prehydrolyzed tetraethylorthosilicate (TEOS) to the colloidal AlPO-18 suspension prior to support seeding. The stabilized seed layers and the grown AlPO-18 films were stable. The structure and the morphology of the films …

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Atomistic Simulation Of Energetic And Entropic Elasticity In Short-Chain Polyethylenes, David Keffer, T. C. Ionescu, V. G. Mavrantzas, B. J. Edwards Jan 2008

Atomistic Simulation Of Energetic And Entropic Elasticity In Short-Chain Polyethylenes, David Keffer, T. C. Ionescu, V. G. Mavrantzas, B. J. Edwards

David Keffer

The thermodynamical aspects of polymeric liquids subjected to uniaxial elongational flow are examined using atomistically detailed nonequilibrium Monte Carlo simulations. In particular, attention is paid to the energetic effects, in addition to the entropic ones, which occur under conditions of extreme deformation. Atomistic nonequilibrium Monte Carlo simulations of linear polyethylene systems, ranging in molecular length from C24 to C78 and for temperatures from 300 to 450 K, demonstrate clear contributions of energetic effects to the elasticity of the system. These are manifested in a conformationally dependent heat capacity, which is significant under large deformations. Violations of the hypothesis …

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Energetic And Entropic Elasticity Of Nonisothermal Flowing Polymers: Experiment, Theory, And Simulation, David Keffer, T. C. Ionescu, B. J. Edwards, V. G. Mavrantzas Jan 2008

Energetic And Entropic Elasticity Of Nonisothermal Flowing Polymers: Experiment, Theory, And Simulation, David Keffer, T. C. Ionescu, B. J. Edwards, V. G. Mavrantzas

David Keffer

The thermodynamical aspects of polymeric liquids subjected to nonisothermal flow are examined from the complementary perspectives of theory, experiment, and simulation. In particular, attention is paid to the energetic effects, in addition to the entropic ones, that occur under conditions of extreme deformation. Comparisons of experimental measurements of the temperature rise generated under elongational flow at high strain rates with macroscopic finite element simulations offer clear evidence of the persistence and importance of energetic effects under severe deformation. The performance of various forms of the temperature equation are evaluated with regard to experiment, and it is concluded that the standard …

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