bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Type of Partnership for Science Outreach: Princeton Center for Complex Materials, Strange Matter and the Liberty Science Center
Authors: Steinberg Daniel 
Published: April 2011

AbstractAll National Science Foundation funded MRSEC centers have education, outreach and community service as one of their major objectives. The Princeton Center for Complex Materials (PCCM) takes this commitment very seriously. PCCM runs a full slate of education activities including a host of Pre-college science and engineering programs and a research experience for undergraduates and teachers program each summer. Our outreach programs are designed to increase awareness, appreciation and knowledge of materials science.Liberty Science Center (LSC) in Jersey City, New Jersey and the Strange Matter traveling exhibit allowed PCCM to expand its outreach program to include tens of thousands of family audience members. LSC gets 1000's of visitors each weekend, and has expertise in communicating with this audience. Princeton University scientists have expertise in materials science. This partnership required coordination between the LSC staff and the PCCM outreach director in facilitating the training and presentations by faculty and other scientists from Princeton. Together we developed a program that sent over 30 scientists from Princeton University to the liberty science center to offer their enthusiasm for material science to the public. Scientists can reach a much larger audience at a science center than at their home institutions. This can be repeated anywhere in the country where there are science centers is and university research centers willing to work together.
Exploring Materials Science with LEGO® Brick Models
Authors: Campbell Dean J. 
Published: April 2011

AbstractVarious physical and chemical principles related to materials science and technology can be demonstrated with LEGO® models. Three-dimensional models are excellent tools for grasping structure-function relationships. Additionally, many people are familiar with LEGO® bricks, and most models can be built with a level of mechanical sophistication that does not intimidate or frustrate the user. LEGO® bricks typically have many connection sites, allowing tremendous flexibility in the structures that can be built. The bricks can be used to model both the structures of materials and the techniques used to study them. Many models can be built with varying degrees of sophistication, even incorporating electronics, enabling the user to focus on relatively simple concepts or more subtle details. The variety of models available also enables LEGO® bricks to fit into a variety of user budgets. This paper features models of the structures of materials, including unit cells, discrete molecules, and polymers. It also features models of analytical tools used to study materials, including models of a scanning probe microscope and a photometer. Details and building instructions of these and other models are featured in the book “Exploring the Nanoworld with LEGO® Bricks”. This book may be downloaded from the Internet at: http://mrsec.wisc.edu/edetc/LEGO/index.html.
Accommodating Different Learning Styles Using e.g., “Flash Movies” in an Introductory Course on Materials Science.
Authors: Harrison I. R. , Ray P. C. , Fleck M. , Locklin R. H. , Weisner A. , Howell P. R. 
Published: April 2011

ABSTRACTIn addition to a hard-copy textbook, Power-Point presentations and videos, the authors have developed a series of Flash modules and on-line quizzing tools for use in teaching and assessing the fundamentals of Materials Science and Engineering. The original thrust was aimed at non-science majors at university, but the modules are also designed for ease of use in high school curricula. In the current paper, we present our philosophy for the presentation of materials' related subject material, using different learning objects, by describing one particular module: on electronic materials.
Experimental Study on the Mechanism of Ethanol/Bentonite Slurry Grouting
Authors: Ishii Takashi , Iwasa Kengo , Shiraishi Tomonari , Saito Akira , Nakashima Hitoshi , Asada Motoyuki , Ueda Hiroyoshi , Sakabe Yasushi 
Published: April 2011

ABSTRACTTo ensure safety and efficiency of construction and operation of repositories, rock fractures need to be grouted where they intersect the facility. Cement-based grouting materials that have been used extensively in the past may, however, react with the groundwater and produce hyperalkaline leachate. A possible solution for this issue is use of alternative material.Ethanol/Bentonite Slurry Grouting is another approach to minimize the long-term permeability of rock fractures. The slurry has high fluidity for the case of the ethanol concentration in the liquid phase being 60%. The viscosity of the slurry with bentonite content of 0.4 Mg/m3 was measured for conditions of the shear rate ranging from 0.1 to 1000 1/s. The viscosity of the slurry changed dramatically between the ethanol concentrations of 60 to 40 %, behaving as a non-Newtonian fluid. In order to investigate when the ethanol content of the slurry becomes low enough to achieve sufficient viscosity in rock fractures, an Ethanol Diffusion Test with experimental openings was carried out in the laboratory. Extrapolation of the measured minimum time for the filled slurry to reach the desirable low concentration of ethanol lead to the estimated minimum time ranging from 0.1 hours to 0.7 hours for a 0.2 mm aperture. These facts suggest that the injected slurry flows through the openings of fractures during the early period of injection and, later, as its ethanol content decreases, slurry's viscosity increases sufficiently so that the openings can be blocked.
Some Methodological Modifications of Determination of Diffusion Coefficients in Compacted Bentonite
Authors: Vopálka Dušan , Filipská Helena , Vokál Antonín 
Published: April 2011

ABSTRACTThe results of 3H, 36Cl and 137Cs diffusion experiments through compacted bentonite using a new design of diffusion cell and a new methodology of diffusion coefficients evaluation are presented. The diffusion cell was made from the stainless steel and enables to connect it directly to the input and/or output reservoirs without any tubing. The evaluation of diffusion coefficients utilizes a compartmental model developed in the environment of the GoldSim transport code. It enables to determine diffusion coefficients for various types of boundary conditions, including also input and output filters. The influence of the diffusion through filters on the determined values of both effective (De) and apparent (Da) diffusion coefficients was numerically demonstrated for the through diffusion method. This effect is most important for Da, the value of which would be underestimated using standard ways of evaluation for neutral and positively charged species, mainly in the case of high effective porosity.The comparison of standard and the newly developed method of evaluation of diffusion coefficients showed a significant influence of diffusion in filters for HTO. Contrary to the standard method of evaluation, the evaluation taking into account filters showed here no difference between total and effective porosity. The effect of filter resistance was negligible for Cl-, especially at high dry density of compacted bentonite, due to the anion exclusion effect. The numerical model developed enabled to determine Da values of Cs+ from the concentration change in the inlet reservoir.
Testing of a near-field biogeochemical model against data from a large-scale gas generation experiment
Authors: Small J.S. , Nykyri M. , Paaso N. , Hovi U. , Itävaara M. , Sarlin T. 
Published: April 2011

ABSTRACTA biogeochemical model that represents processes of metal corrosion, microbial degradation of cellulosic waste and mass transfer within a heterogeneous system has been used to represent processes of gas generation in a large-scale (20m3) experiment that has studied degradation of typical nuclear reactor operating waste. The experiment has been in operation for a period of about eight years and has established a pattern of methanogenic gas generation. A “blind testing” approach has been used to develop the model of the experiment using independently derived kinetic data for corrosion and microbial processes. The model correctly represents the anaerobic conditions leading to methane generation during the course of the experiment. The overall rate of gas generation of the experiment is well represented, as is the composition of evolved gases and geochemistry of sampled liquids. The experiment and the model together build confidence in the ability to simulate processes of gas generation and variation in chemical conditions in heterogeneous repository environments.
The JNC Generic URL Research Program - Providing a Knowledge Base to Support both Implementer and Regulator in Japan
Authors: Umeki Hiroyuki , Shimizu Kazuhiko , Seo Toshihiro , Kitamura Akira , Ishikawa Hirohisa 
Published: April 2011

ABSTRACTIn accordance with the R&D framework specified by the Atomic Energy Commission of Japan in 2000 for the implementing phase of HLW disposal, the Japan Nuclear Cycle Development Institute (JNC) continues to be responsible for R&D activities aimed at enhancing the reliability of disposal technologies and safety assessment methodologies and associated databases. JNC has thus been actively promoting technical R&D with a view to contributing to both the implementation of disposal and the formulation of safety regulations.One of JNC's key roles is to establish and demonstrate site characterization methodologies based on investigations in two purpose-built generic URL (underground research laboratory) projects: one at Mizunami in crystalline rock and the other at Horonobe in sedimentary rock.Through the surface-based investigations in the Mizunami and Horonobe projects (phase 1), integration of work from different disciplines into a “geosynthesis” has been illustrated and is planned to be developed further in the underground facilities at these sites (phases 2 and 3). These projects also serve for developing and testing the tools and methodologies required for site characterization. Further know-how will be gained through participation in foreign underground laboratory projects, transfer of experience from these projects to Japan and tailoring it to Japanese conditions and requirements.This experience represents an important knowledge base, which is obviously important for the implementer but is also needed by the regulator, in order to assess how key site characteristics are derived and what uncertainties are associated with this process.
Sorption of Selenium (IV) on Mineral Mixtures: Role of Minor Phases in the Modelling Part
Authors: Charlotte Hurel , Nicolas Marmier 
Published: April 2011

ABSTRACTSorption processes have been largely studied and modelled by considering single mineral surfaces (iron oxides, clay etc). In the case of a complex surface such as claystone, it seems important to be able to predict the behaviour of the radioactive elements in contact with the natural site. The modelling part becomes very complex if the whole minerals composing the geological media have to be taken into account. In that way, this study aims at testing various mineral mixtures, to identify the most reactive phase controlling the adsorption processes, in order to get a “simplified” system for a model calculation. Various mineral assemblages (goethite, pyrite, calcite and montmorillonite) were studied here, in contact with an anionic specie (selenium). Experiments were carried out using single, binary, ternary or quaternary solid mixtures, in order to evaluate the major reactive mineral phase. A surface complexation model was then considered to fit the experimental data. Stoichiometries and constants were extracted using FITEQL by fitting experimental results obtained on single solid in NaNO3, and used in a predictive calculation with PHREEQC for mixtures in synthetic grounwater. By doing this, we wanted to verify if the assumption that surface reactivity of single minerals keeps the same in a different environment can be used for predictive calculations.Results obtained have shown that the presence of calcite and pyrite does not influence the total amount of selenium adsorbed. Then a simplified model was proposed, taking into account only the major phase responsible for the sorption of Se.
Selenium Sorption in a Sedimentary rock/saline Groundwater System and Spectroscopic Evidence
Authors: Xia X. , Kamei G. , Iijima K. , Shibata M. , Ohnuki T. , Kozai N. 
Published: April 2011

ABSTRACTSorption of selenium (Se) was studied by batch technique by using sedimentary rock samples andcorresponding saline groundwater from Horonobe underground research laboratory (URL)site under reducing condition. Spectroscopic analyses were performed by X-ray absorption near-edge structure (XANES) afterthe sorption experiments to identify the oxidation states of Se on the sedimentary rock. It issuggested thatthe dominant parameters affecting the Se sorption are iron-bearing minerals, especially exchangeable Fe and pyrite, and organic matters. Most of the Se sorbed on the sedimentary rock was Se(0) inthe case of natural saline groundwater, at least at relatively high Se concentration, while only part of the Se was Se(0) in caseof the synthetic groundwater, which contains no organic matters. Incorporationinto pyrite could be the sorption mechanism of Se(0).
The Sorption of Thorium and Americium onto Fresh and Degraded Ordinary Portland Cement and onto Green Tuff
Authors: Cowper Mark M. , Baker Sarah , Chambers Adam V. , Heath Timothy G. , Mihara Morihiro , Williams Stephen J. 
Published: April 2011

ABSTRACTThe sorption of thorium and americium has been measured onto crushed samples of freshordinary Portland cement (OPC), degraded OPC (DOPC) and green tuff under a range of aqueous conditions as part of research into the disposal of TRU waste in Japan. Sorption onto OPC was measured from deionised water,3 mol dm−3sodium nitrate solution and simulated seawater, and onto DOPC from demineralised water; all solutions were pre-equilibrated with the relevant cement. Sorption onto tuff was measured from pre-equilibrated deionised water, 3 mol dm−3sodium nitrate solution, simulated seawater, OPC leachate and 1 mol dm−3ammonium hydroxide solution. RDvalues were determined from the amount of thorium or americium remaining in solution after centrifugation, 0.45 μm filtration and 10,000 nominal molecular weight cut-off (NMWCO) filtration. Centrifugation gave lower RDvalues than filtration. MeanRDvalues for sorption onto OPC and DOPC were in the range 4 × 104to ≥1 × 106cm3g−1for thorium, and 3 ×103to ≥1 × 105cm3g−1for americium, after filtration through 10,000 NMWCO filters. Mean RDvalues for thorium sorption onto tuff increased from2 × 103cm3g−1in tuff-equilibrated deionised water, to ≥ 4 × 106cm3g−1from ammonium hydroxide solution (10,000 NMWCO-filtration). A similar trend was seen for10,000 NMWCO-iltered americium samples where mean RDvalues increased from 4 × 103cm3g−1in deionised water to 1 × 105cm3g−1in ammonium hydroxide solution.
Modelling uranium leaching from agricultural soils to groundwater as a criterion for comparison with complementary safety indicators
Authors: Jacques D. , Šimůnek J. , Mallants D. , van Genuchten M.Th. 
Published: April 2011

ABSTRACTNaturally occurring radionuclides can also end up in soils and groundwater due to human practices, such as application of certain fertilizers in agriculture. Many mineral fertilizers, particularly (super)phosphates, contain small amounts of 238U and 230Th which eventually may be leached from agricultural soils to underlying water resources. Field soils that receive P-fertilizers accumulate U and Th and their daughter nuclides, which eventually may leach to groundwater. Our objective was to numerically assess U migration in soils. Calculations were based on a new reactive transport model, HP1, which accounts for interactions between U and organic matter, phosphate, and carbonate. Solid phase interactions were simulated using a surface complexation module. Furthermore, all geochemical processes were coupled with a model accounting for dynamic changes in the soil water content and the water flux. The capabilities of the code in calculating natural U fluxes to groundwater were illustrated using a semi-synthetic 200-year long time series of climatological data for Belgium. Based on an average fertilizer application, the input of phosphate and uranium in the soil was defined. This paper discusses calculated U distributions in the soil profile as well as calculated U fluxes leached from a 100-cm deep soil profile. The calculated long-term leaching rates originating from fertilization are significantly higher after 200 years than estimated release rates from lowlevel nuclear waste repositories.
The Electrochemistry of Copper in Aqueous Sulphide Solutions
Authors: Smith J. , Qin Z. , King F. , Werme L. , Shoesmith D.W. 
Published: April 2011

ABSTRACTUsing a variety of electrochemical and surface analytical techniques, the mechanism and kinetics of Cu corrosion in anoxic, aqueous, sulphide-containing environments are being investigated. Under these conditions ([S]total = 10−4 to 3 ×10−3 mol/L), the anodicgrowth ofa film (XRD identifies Cu2S/Cu1.8S as major/minor phases, respectively) is supported by the cathodic reduction of water thereby destabilizing the copper surface. For more oxidizing conditions, the subsequent growth of a partially passivating film is observed. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry at rotating disc electrodes show film growth occurringwith negligible dissolution and under partial SH- transport control. Current-potentialrelationships as a function of [S]total give Tafel slopes of ∼ (40 mV)−1 suggesting reaction occurs via a 2step process: Aninitial rapid adsorption of SH- leading to an equilibrium surface concentration, followed by a rate determining electron transfer to form a sulphide film. It is proposed thatfilm growth propagates via transport of CuI through the film to the solution interface. The primary goal of this research is the development of a mathematical model which can be used to assess the performance of copper nuclear waste canisters in granitic repositories.
Deep Disposal of Eurobitum Bituminised Waste: Scoping Calculations of Nitrate Release
Authors: Weetjens Eef , Sillen Xavier , Valcke Elie 
Published: April 2011

ABSTRACTThe Eurobitum bituminised waste produced by the former EUROCHEMIC reprocessing plant in Mol-Dessel (Belgium) contains a lot of salts, mainly NaNO3. This NaNO3 may possibly affect significantly the evolution of a radwaste repository through redox and ion exchange reactions with Boom Clay, which in Belgium is studied as a reference host formation. Yet, the leaching behaviour of NaNO3 from the Eurobitum and its migration in the Boom Clay is rather unclear. Therefore, some scoping numerical calculations have been performed. In a first phase, we calculated the water flux towards the disposal gallery to assess the timescale of the saturation process of the disposal galleries. In a second phase, the leaching rate of NaNO3 out of the drums is compared with its diffusive removal through the Boom Clay.The water flux to the gallery was calculated at approximately 100 ml/day per metre gallery, based on the natural pressure gradient observed around the HADES Underground Research Laboratory. Different approaches were elaborated to find a NaNO3 source term for the diffusion calculations. For various ways of characterising the nitrate release, the numerical calculations generally show that the NaNO3 concentrations in the first decimetres of Boom Clay will not be much higher than 1 M. Moreover, a sensitivity analysis showed that if the nitrate is released from the bituminised waste product within 10 000 years, the Boom Clay controls the concentration profiles; if the release is slower, the source term has a more pronounced effect on the near field concentrations.
Ageing of Eurobitum Bituminised Radioactive Waste under Gamma Irradiation
Authors: Rorif Fabian , Valcke Elie , Boven Patrick , Ooms Hans , Peeters Jozef , Smets Steven 
Published: April 2011

ABSTRACTThe extent of the physico-chemical processes of concern in the study on the acceptability of the Belgian Eurobitum bituminised waste for underground disposal will depend on the degree ofageing of the bituminous matrix. Therefore, the ageing of non-radioactive simulates of Eurobitum under gamma irradiation was studied both in the presence and absence of oxygen. Chemical changes in the bitumen structure were measured in the mid-infrared region with the attenuated total reflectance infrared technique (ATR/FTIR) and evaluation of the peaks at 1700 cm−1 (C=O) and 1600 cm−1 (C=C). Even for the highest total absorbed doses (∼800 kGy at ∼150 Gy/h), the effect of the irradiation in Eurobitum was found to be small and was, in any case, smaller than for samples heated for three hours at 130°C in air.
Synthesis and characterisation of transition metal substituted barium hollandite ceramics
Authors: Hyatt Neil C. , Stennett Martin C. , Fiddy Steven G. , Wellings Jayne S. , Dutton Sian S. , Maddrell Ewan R. , Connelly Andrew J. , Lee William E. 
Published: April 2011

ABSTRACTA range of transition metal bearing hollandite phases, formulated Ba1.2B1.2Ti6.8O16 (B2+ = Mg, Co, Ni, Zn, Mn) and Ba1.2B2.4Ti5.6O16 (B3+ = Al, Cr, Fe) were prepared using an alkoxide - nitrate route. X-ray powder diffraction demonstrated the synthesis of single phase materials for all compositions except B = Mn. The processing conditions required to produce > 95 % dense ceramics were determined for all compositions, except B = Mg for which the maximum density obtained was > 93 %. Analysis of transition metal K-edge XANES data confirmed the presence of the targeted transition metal oxidation state for all compositions except B = Mn, where the overall oxidation state was found to be Mn3+. The K-edge EXAFS data of Ba1.2B1.2Ti6.8O16 (B = Ni and Co) were successfully analysed using a crystallographic model of the hollandite structure, with six oxygen atoms present in the first co-ordination shell at a distance of ca. 2.02Å. Analysis of Fe K-edge EXAFS data of Ba1.2B2.4Ti5.4O16 revealed a reduced co-ordination shell of five oxygens at ca. 1.99Å.