bluuebunny/crossref_metadata_2025_split huggingface dataset:
R & D and Business Opportunities for Nanotech Companies in Singapore
Authors: Liu Lerwen 
Published: April 2011

AbstractSingapore, located at the centre of Asia, is an ideal dynamic hub to converge advanced R & D and industry leaders, robust alliances, new technologies and world class infrastructure. In the field of nanotechnology, Singapore is equipped with state of the art facilities (one of the best in the world) for nanotechnology R & D and it has unique open research environment for encouraging and attracting international collaboration and industry cooperation. Combining its efficient government administration and international business and financial environment, Singapore is becoming an attractive place for setting up leading R & D centres, research and development partnerships for research institutions and industries, and for locating company regional headquarters. Singapore government is aggressively promoting innovation and launched attractive funding schemes in help fostering SMEs and spin offs from research institutions. Singapore government has committed SGD 13.55 Billion (USD10B) on R & D for the period of 2006-2010 (over 200% increase from the previous 5 year period), making Singapore GERD to 3% of GDP by 2010. Singapore is not only a melting point of diverse cultures but most importantly a place for exciting converging technologies, global partnerships and creates growth nanotech industries. In this article we give an overview on the Singapore public and private financing schemes for nanotech R & D and commercialisation. Incentives for supporting start-ups as well as R & D partnerships with research institutes are summarized. We outlined the world-class infrastructure for nanotech R & D. Summary of nanotech R & D efforts are highlighted.
Nanomonitors: Electrical Immunoassays for Protein Biomarker Profiling
Authors: Bothara Manish , Reddy Ravi K , Barrett Thomas , Carruthers John , Prasad Shalini 
Published: April 2011

AbstractThe objective of this research is to develop a “point-of-care” device for early disease diagnosis through protein biomarker characterization. Here we present label-free, high sensitivity detection of proteins with the use of electrical immunoassays that we call Nanomonitors. The basis of the detection principle lies in the formation of an electrical double layer and its perturbations caused by proteins trapped in a nanoporous alumina membrane over a microelectrode array platform. High sensitivity and rapid detection of two inflammatory biomarkers, C-reactive protein (CRP) and Myeloperoxidase (MPO) in pure and clinical samples through label-free electrical detection were achieved. The performance metrics achieved by this device makes it suitable as a “lab-on-a-chip” device for protein biomarker profiling and hence early disease diagnosis.
Exploiting Nanotech Opportunities: A Strategic Entrepreneurship Perspective
Authors: Baglieri Daniela , Giordani Sara 
Published: April 2011

AbstractThis paper analyzes the main challenges nanotech start-ups face in turning nanotech inventions into valuable and marketable nanotech innovations, also considering that nanotechnology discoveries could represent “inventions of methods of inventing” (Rothaermel et al., 2007). In the last decades, nanotechnologies have been a burgeoning area of science and engineering which show an increasing potential to transform a broad range of industries, and to boost the US and European firms' competitiveness (OECD, 1998). Although these emerging technologies share some problems with new ventures in other emerging industries ( e.g. biotech), nanotechnology firms have to balance the management of high technical and high market risk, still evolving regulatory frameworks (Bowman et al. 2006) and strategies for entering the business network and for attracting investments, e.g. in the form of potential venture capitalists. Potential investors, in turn, will face the well-known hurdle of the due diligence, considering for example health or safety concerns, manufacturing, availability of distribution channels, etc. (Burden, 2007).We propose that configuring their network and choosing the right market segment are the key strategies nanotech ventures should adopt in pushing their early growth in the global market. We analyze a sample of 15 European nanotech firms which confirm our predictions. Due to the novelty of the topic covered in this study, this research is exploratory in nature.
The Immobilisation of Clinoptilolite Within Cementitious Systems
Authors: Gordon L. E. , Milestone N. B. , Angus M. J. 
Published: April 2011

AbstractThe zeolitic ion exchanger clinoptilolite was encapsulated within various cementitious systems in order to assess their suitability for the retention of the radioelements, Cs and Sr. The pozzolanic reaction of clinoptilolite is reduced in composites containing BFS and PFA and appears not to continue after 7 days of hydration. Ca(OH)2 persists up to 360 days of hydration in a 9:1BFS:OPC system with 10% clinoptilolite added, despite the presence of unreacted pozzolan. This may be due to low pH of the pore solution, if Na and K act as counter cations in the aluminous C-S-H, a product of pozzolanic hydration or are exchanged onto the clinoptilolite. Saturation of the pore solution with Ca may prevent further dissolution of Ca(OH)2. Cs leaching occurs in all samples during accelerated tests due to breakdown of the clinoptilolite structure.The alternative cement system calcium sulfoaluminate cement (CSA) has a different hydration chemistry and properties to OPC and OPC composites with a lower pore solution pH. Clinoptilolite appears to react in a hydrating CSA system with significant reaction continuing between 28 and 90 days of hydration. Leaching of Cs from CSA is higher than from an OPC system, in which almost all of the clinoptilolite crystallinity is lost. The major product of CSA hydration is ettringite. Cs may be adsorbed within cation sites of the C-S-H in an OPC system but not by ettringite which does not retain Cs so Cs has high mobility and leachability through the CSA matrix.
Processes Related to the Water Uptake by EUROBITUM Bituminised Radioactive Waste: Theoretical Considerations and First Experimental Results
Authors: Mariën An , Smets Steven , Li Xiangling , Valcke Elie 
Published: April 2011

AbstractAccording to the present Belgian radioactive waste management program, Eurobitum bituminised radioactive waste will be disposed of in a geologically stable underground clay formation. The Boom Clay is studied as a potential host formation because of its low diffusion and high retention properties towards radionuclides. The presence of the radioactive waste should not disturb these properties. Due to the presence of hygroscopic salts (25 to 30 weight% NaNO3), Eurobitum will take up pore water which will result in a swelling and possibly in a very high swelling pressure. First scoping calculations suggest that the swelling pressure exerted to Boom Clay should remain below 7 to 8 MPa to avoid the formation of fractures. If the bitumen in EUROBITUM behaved like a perfect semi-permeable membrane and if no swelling were allowed after the dissolution of NaNO3 into a saturated solution of 10.8 M, osmotic pressures of ∼50 MPa could be attained. To better understand the interaction between the swelling Eurobitum and the host formation, coupled hydro-chemical-mechanical constitutive laws for Eurobitum have to be developed. To this purpose, water uptake tests under constant volume (‘confined’) and constant stress (‘semi-confined’) conditions are being performed. After ∼2 years of hydration of small inactive Eurobitum samples in constant volume conditions, the swelling pressure has raised to ∼12 MPa. The volume of samples that can swell against counter pressures of 2.2, 3.3, or 4.4 MPa (constant stress tests) increased with ∼5 to 11 volume%, independently of the applied counter pressure. Approximately 10 weight% of the initial NaNO3 content has been leached.
Determination of the Forward Rate of Dissolution for SON68 and PAMELA Glasses in Contact With Alkaline Solutions
Authors: Ferrand K. , Lemmens K. 
Published: April 2011

AbstractIn the new Belgian disposal design, the nuclear waste glass will be surrounded by a 3 cm thick carbon steel overpack and a 70 cm thick concrete buffer. An initially high pH is expected after water intrusion in the concrete buffer and this may have an effect on the radionuclide release from the waste glass. This study was performed in order to determine the forward rate of dissolution for SON68 and PAMELA glasses (SM513 LW11 and SM539 HE 540-12), conducting dynamic tests at 30°C in contact with alkaline solutions. In these experiments, the silicon concentration in solution was determined by UV/Visible spectrophotometry according to the blue â-silicomolybdenum method. The forward rates of dissolution were quite similar for the three glasses except at the highest pH for which a slightly higher value was found for SM539 glass. For SON68 glass, a good agreement with the previously established interpolation law was observed until pH 11.5, but at higher pH, the interpolation law slightly overestimates the dissolution rate [1].
Single Idealized Cracks: A Tool for Understanding Fractured Glass Block Leaching
Authors: Chomat Laure , Bouyer Frédéric , Gin Stéphane , Roux Stéphane 
Published: April 2011

AbstractWithin the scope of the long term behaviour of the R7T7 glass, which is the French nuclear glass, leaching and its coupling with transport mechanisms is studied. Experiments carried out on a SON 68 glass (inactive R7T7 type glass) model cracks in static basic conditions show a strong coupling between solution transport and glass leaching, depending on crack aperture. Moreover, gravity driven convective transport was evidenced for vertical model cracks, whereas only molecular diffusion was detected for horizontal model cracks under the same alteration conditions. In addition, an original device was developed to study the influence of temperature gradients on alteration kinetics as a convective driving force. These experiments show conclusively that thermally- or gravity-induced convective flow must be taken into account, even if such convective effects have not been established experimentally in neutral condition, which is more realistic condition for geological storage. A modeling, based on a porous geochemical software (HYTEC) accounting for both chemistry and transport, has been successfully applied to describe alteration within simple silicate glass cracks. It will be extended to study SON 68 glass model cracks, and more complex fracture networks.
Plutonium Feed Impurity Testing in Lanthanide Borosilicate (LaBS) Glass
Authors: Fox Kevin M. , Marra James C. , Edwards Thomas B. , Hoffman Elizabeth N. , Crawford Charles L. 
Published: April 2011

AbstractA vitrification technology utilizing a lanthanide borosilicate (LaBS) glass is a viable option for dispositioning excess weapons-useable plutonium that is not suitable for processing into mixed oxide (MOX) fuel. A significant effort to develop a glass formulation and vitrification process to immobilize plutonium was completed in the mid-1990s. The LaBS glass formulation was found to be capable of immobilizing in excess of 10 wt % Pu and to be tolerant of a range of impurities. A more detailed study is now needed to quantify the ability of the glass to accommodate the anticipated impurities associated with the Pu feeds now slated for disposition.The database of Pu feeds was reviewed to identify impurity species and concentration ranges for these impurities. Based on this review, a statistically designed test matrix of glass compositions was developed to evaluate the ability of the LaBS glass to accommodate the impurities. Sixty surrogate LaBS glass compositions were prepared in accordance with the statistically designed test matrix. The heterogeneity (e.g. degree of crystallinity) and durability (as measured by the Product Consistency Test – Method A (PCT–A)) of the glasses were used to assess the effects of impurities on glass quality.
Radionuclides Release From the Spent Fuel Under Disposal Conditions: Re-evaluation of the Instant Release Fraction
Authors: Ferry Cécile , Piron Jean-Paul , Poulesquen Arnaud , Poinssot Christophe 
Published: April 2011

AbstractThe so-called Instantaneous Release Fraction (or IRF) corresponds to the rapid release of radioactivity by the spent fuel rod at the canister breaching time in repository and depends on the spent fuel evolution in a closed system. The effect of He accumulation on the spent fuel pellet microstructure and diffusion processes are here re-assessed in the light of the recent results issued from the projects Near-Field PROcesses and PRECCI. It allows diminishing the conservatism of the former IRF values of key safety relevant radionuclides for PWR UO2 fuels.
Effect of Weak Acid Additions on the General and Localized Corrosion Susceptibility of Alloy 22 in Chloride Solutions
Authors: Carranza Ricardo M. , Giordano C. Mabel , Rodríguez Martín A. , Rebak Raul B. 
Published: April 2011

AbstractElectrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90°C. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric acids.Results show that the CR of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and Picric acids showed a slightly higher CR, and Acetic acid maintained the CR of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions.Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids.
Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines
Authors: Rebak Raul B. , Ilevbare Gabriel O. , Carranza Ricardo M. 
Published: April 2011

AbstractA comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75°C and at 90°C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions
Modeling of Radionuclide Migration Through Fractured Rock in a HLW Repository With Multiple Canisters
Authors: Lim Doo-Hyun , Uchida Masahiro , Hatanaka Koichiro , Sawada Atsushi 
Published: April 2011

AbstractAn integrated numerical model for groundwater flow and radionuclide migration analyses in a water-saturated HLW repository with a multiple-canister configuration is developed by incorporating the heterogeneity of fractured host rock based on the previous multiple-canister model (MCFT2D [1, 2]). The current model incorporates i) heterogeneity of the fractured host rock represented stochastically by discrete fractures, ii) disposal-pit vertical emplacement concept, iii) representation of the waste package consisting of a waste canister and a bentonite-filled buffer, and iv) a user-determined repository configuration of multiple canisters using the repository parameters such as disposal tunnel spacing, waste package pitch, tunnel diameter, the number of tunnels in a repository, and the number of canisters in a tunnel. The current model can facilitate investigations into the effects of heterogeneous fractured host rock on water flow and nuclide migration for the different configurations of multiple canisters, as well as optimization of the repository design parameters in terms of release of nuclides from the repository.
Development and Validation of a Model of Uranium Release to Groundwater From Legacy Disposals at the UK Low Level Waste Repository
Authors: Small J.S. , Lennon C. , Kwong S. , Scott R.J. 
Published: April 2011

AbstractA previous radiological assessment of the UK Low Level Waste Repository (LLWR) has considered how the prevailing reducing chemical conditions in disposal trenches, may limit uranium release through the extreme low solubility of U(IV) solids. This study considers the additional effects that the physical and chemical nature of the uranium wastes may have on the release of uranium. Fluoride process residues produced by refining of uranium metal comprise the majority of the legacy inventory. Based on historic records and descriptions of the uranium wastes a conceptual model has been developed which bounds the release rate of uranium present as inclusions and dissolved in the solid residues by the dissolution rate of a magnesium fluoride matrix. The model is represented in a 3-dimensional groundwater flow and geochemical model. Initial findings indicate that the model correctly represents the range of fluoride and uranium concentrations that are measured in leachate from the LLWR trenches. Incorporation of this model in future safety assessments, together with a reduction in the derived inventory of uranium, is likely to result in a significant lowering of the peak groundwater dose to acceptable levels, even in the case that the site re-oxidizes. The study builds confidence in the inherent safety features that are provided by the sparingly soluble uranium waste residues and the reducing chemical conditions of the LLWR trenches.
Illustration of HLW Repository Performance: Using Alternative Yardsticks to Assess Modeled Radionuclide Fluxes
Authors: Miyahara Kaname , Kato Tomoko 
Published: April 2011

AbstractComplementary indicators have been used in developing a safety case in order to avoid uncertainties in the biosphere modeling used to estimate conventional dose or risk. For example, radionuclide fluxes can be used to evaluate the effectiveness of barrier performance. However, it is difficult to define relevant yardsticks for comparison, because the fluxes of naturally occurring radionuclides due to geological processes vary considerably depending on time and location. This paper discusses the relevance of alternative yardsticks for assessing modeled radionuclide fluxes by selecting yardsticks calculated from fluxes of natural radionuclides at the groundwater discharge point from the geosphere to an aquifer; these are then compared with fluxes of repository-derived radionuclides at the same point. Such yardsticks avoid surface geological processes that may also contribute to natural fluxes, allowing comparison at a suitable, common evaluation point that avoids dependence on site-specific conditions. The effectiveness and robustness of barrier performance is demonstrated using the developed yardsticks and the sensitivity of the analysis to groundwater flux is illustrated.
Fabrication and Photoelectrical Properties of AZO/SiO2/p-Si Based Device
Authors: Ma Z.Q. , He B. , Xu J. , Zhao L. , Li F. , Zhang N.S. , Meng X. J. , Shen L. , Shen C. 
Published: April 2011

AbstractIn order to fabricate AZO/SiO2/p-Si heterojunction device and let it be an absorber of ultraviolet response cell. Zinc oxide (ZnO) thin films doped with aluminum (AZO) were deposited on p-Si(100) substrates covered with silicon dioxide (SiO2) by radio frequency magnetron sputtering. The optical and electrical properties of the Al doped - ZnO films were characterized by UV-VIS spectrophotometer, current-voltage measurement, and four point probe technique, respectively. The results show that the device is a typical tunneling diode for minority carrier and a strong obstructing effect from majority carriers. The potential rectifying behavior and photovoltaic characteristic is present at dark current and weak light illumination, respectively.
Method of Fast Hydrogen Passivation to Solar Cell Made of Crystalline Silicon
Authors: Sun Wen-Ching , Lin Jian-Hong , Chang Wei-Lun , Huang Tien-Heng , Wang Chih-Wei , Lin Jia-De , Kou Chwung-Shan , Lin Jian-You , Chen Sheng-Wei , Hwang Jenn-Chang , Gan Jon-Yiew 
Published: April 2011

AbstractPlasma immersion ion implantation (PIII) is a technique of material processing and surface modification, using controllable negative high voltage pulsed bias to attract the ion generated from the plasma. The method using PIII treatment quickly improves the performance of solar cell made of crystalline silicon, including monocrystalline, multicrystalline and polycrystalline silicon. Hydrogen ions are attracted and quickly implanted into solar cell under a predetermined negative pulse voltage, thus, the passivation of the crystal defects of the solar cell can be realized in a short period. Meanwhile, the properties of the antireflection layer can not be damaged as the proper operating conditions are used. Consequently, the series resistance can be significantly reduced and the filling factor increases as a result. Both the short-circuit and the open-circuit voltage can be increased. The efficiency can be enhanced.
CuIn(Se,S)2 Absorbers Processed using a Hydrazine-Based Solution Approach
Authors: Liu Wei , Mitzi David B. , Chey S. Jay , Kellock Andrew 
Published: April 2011

AbstractWith tunable bandgap and demonstrated high efficiency, the chalcopyrite CuInSe2 and its alloys have shown great potential as absorbers for single and multi-junction solar cells. However, the current deposition techniques mostly rely on expensive vacuum-based processing or involve complicated precursor solution preparation. These higher-cost absorber preparation processes make it difficult to commercialize this technology. In this work, CuInSe2−xSx (CIS) absorbers are deposited using a simple hydrazine-based solution process. Precursor solutions were prepared by dissolving the component metal chalcogenides and chalcogen in hydrazine, forming homogeneous solutions containing adjustable concentrations of desired elements mixed on a molecular level. These precursor solutions are then spin coated on substrates followed by a heat treatment in an inert environment to produce high quality CIS thin films. Significantly, no post deposition selenization process is required using this technique. Laboratory scale devices with conventional glass/Mo/CIS/CdS/i-ZnO/ITO structure have been fabricated using CIS absorbers deposited via this process. For the baseline low-bandgap CIS system with no Ga added (to compare with our previously reported results with Ga incorporated), AM1.5G conversion efficiency of as high as ∼9% has been achieved for devices with 0.45 cm2 effective area.
Ultrafast Laser Textured Silicon Solar Cells
Authors: Nayak Barada K. , Iyengar Vikram , Gupta Mool C. 
Published: April 2011

AbstractA novel ultrafast laser texturing method has been developed to produce arrays of nano/micro surface textures in silicon. Laser processing conditions have been optimized for achieving appropriate optical and electronic properties for photovoltaic applications. The textured silicon surfaces absorb greater than 99% of incident light over the entire solar spectrum and the material appears complete black to bare eye. Textured silicon surfaces are characterized for surface morphology and optical properties. Chemical etching and thermal annealing steps have been performed to remove laser slag and induced defects. Finally, we report the total and external quantum efficiency results on photovoltaic devices fabricated on the textured silicon wafers, which can be further improved.