Predicting Water Activity in Electrolyte Solutions With the Cisternas-Lam Model

Water activity is an important parameter needed to predict the solubility of hydrated salts in Hanford nuclear waste supernatants. A number of models available in the scientific literature predict water activity from electrolyte solution composition. The Cisternas-Lam model is one of those models and has several advantages for nuclear waste application. One advantage is that it has a single electrolyte specific parameter that is temperature independent. Thus, this parameter can be determined from very limited data and extrapolated widely. The Cisternas-Lam model has five coefficients that are used for all aqueous electrolytes. The present study aims to determine if there is a substantial improvement in making all six coefficients electrolyte specific. The Cisternas-Lam model was fit to data for six major electrolytes in Hanford nuclear waste supernatants. The model was first fit to all data to determine the five global coefficients, when they were held constant for all electrolytes it yielded a substantially better fit. Subsequently, the model was fit to each electrolyte dataset separately, where all six coefficients were allowed to be electrolyte specific. Treating all six coefficients as electrolyte specific did not make sufficient difference, given the complexity of applying the electrolyte specific parameters to multi-solute systems. Revised water specific parameters, optimized to the electrolytes relevant to Hanford waste, are also reported

A Brokering Framework for Assessing Legal Risks in Big Data and the Cloud

“Cloud computing” and “Big Data” are amongst the most hyped-up terms and buzzwords of the moment. After decades in which individuals and companies used to host their data and applications using their own IT infrastructure, the world has seen the stunning transformation of the Internet. Major shifts occurred when these infrastructures began to be outsourced to public Cloud providers to match commercial expectations. Storing, sharing and transferring data and databases over the Internet is convenient, yet legal risks cannot be eliminated. Legal risk is a fast-growing area of research and covers various aspects of law. Current studies and research on Cloud computing legal risk assessment have been, however, limited in scope and focused mainly on security and privacy aspects. There is little systematic research on the risks, threats and impact of the legal issues inherent to database rights and “ownership” rights of data. Database rights seem to be outdated and there is a significant gap in the scientific literature when it comes to the understanding of how to apply its provisions in the Big Data era. This means that we need a whole new framework for understanding, protecting and sharing data in the Cloud. The scheme we propose in this chapter is based on a risk assessment-brokering framework that works side by side with Service Level Agreements (SLAs). This proposed framework will provide better control for Cloud users and will go a long way to increase confidence and reinforce trust in Cloud computing transactions

Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001 (PNW2001) Air Quality Study in Puget Sound, WA

Size and composition are key factors in determining the impact aerosols have on global climate change and human health. The DELTA group at UC Davis has developed sampling techniques that allow continuous collection of aerosols separated into 8 different size fractions with 1-hour time resolution. Total aerosol mass determination: Scanning Transmission Ion Microscopy (STIM) with a 3 MeV proton beam can produce profiles of aerosol mass with an error limit of less than 10%. The aerosol collection strip is scanned with a proton beam of 50 micrometer spatial resolution while recording the proton mean energy loss as a function of position (Bench et al., 1992). A differential beta attenuation mass monitor (beta-gauge) is also used for mass determination. The beta-gauge consists of a 63Ni source and a surface barrier detector. This technique allows quantitative mass measurement by recording attenuation of beta particles through the sample and substrate (Chueinta and Hopke, 2001). Mineral mass and elemental composition: Synchrotron X-ray Fluorescence (s-XRF) is performed at the Advanced Light Source (ALS) at LBNL. The s-XRF technique is quantitative for elements Na through U. The ALS synchrotron provides an extraordinarily intense white beam of X-rays (4-20 KeV) that are 100% polarized. These properties provide us with a very high count rate and a reduced background, giving us exceptional sensitivity. Also, the beam can be focused to a spot on the order of 200 micons yielding time resolution on our sample strips of approximately 1 hour (Cahill et al., 1992). Organic mass determination: Proton Elastic Scattering Analysis (PESA) is performed at the Center for Accelerator Mass Spectrometry at the LLNL. PESA determines the concentration of particulate hydrogen, which is a surrogate for organic aerosol composition (Nejedly et al., 1997). Organic compound determination: Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (LDI-TOFMS) is used to characterize polycyclic aromatic hydrocarbons (PAHs) and their derivatives in aerosols, as well as sulfates and nitrates. We use a low laser power in order to minimize fragmentation, and a wavelength which is resonant for PAH photo-ionization (Bezabeh et al., 1999). Characterization of individual particles: Scanning electron microscopy (SEM) coupled with a state-of-the-art field emission gun (FEG) is used to provide imaging with a resolution capability better than 2 nm (magnifications greater than 600 kX). Single particle analysis by SEM provides elemental composition, heterogeneity information, shape, size, and morphology of individual particles

Comparison of different methods to characterise the abrasivity potential and mechanical properties of carbonates with respect to its relevance for practical purposes in excavation technologies

Abstract The characterisation of the abrasivity potential of carbonates plays an important role for drilling-based excavation technologies, for example in tunneling or geothermal exploration. Although carbonates are known to have a rather low abrasivity, they have been associated with severe excavation performance reductions. We compared different methods to characterise the abrasivity potential of carbonates with respect to its applicability for practical purposes in excavation technologies. In this study, seven carbonate rocks were investigated which differ with respect to their microstructural properties and degrees of dolomitisation. These carbonate rock samples were selected from different lithological units in Germany (Jurassic: Kelheimer limestone, Wachenzell dolomite, Solnhofen limestone, Pappenheim limestone, Treuchtlingen limestone; Devonian: Wülfrath limestone, Brilon limestone). Rock samples were characterised with respect to basic physical properties (density, ultrasound velocity), microstructure (thin section analysis, XRD), mechanical properties (uniaxial compressive strength UCS, splitting tensile strength STS) and commonly applied abrasivity indices (Cerchar abrasivity index test CAI, LCPC test) as well as derived indices (equivalent quartz content eQu). Our results confirm that the tested carbonate rocks show low abrasivity indices in terms of CAI, LCPC and eQu with an increase in abrasivity potential with increasing dolomite content. The microstructural properties play an important role for the abrasiveness of purely calcitic carbonates. Uniaxial compressive strength and splitting tensile strength were high and can additionally be, as has been shown before, particularly sensitive to sample preparation. We conclude that carefully determining the mechanical properties of carbonate rock samples in combination with common approaches to determine the abrasivity potential is key to properly predict tool wear, and required to derive information on performance in carbonate rocks. This study is the outcome of a research-oriented teaching program at Ruhr-University Bochum within the Geoscience curriculum for students with focus on Engineering Geology. Student authors are listed in alphabetical order (Aderhold to Zinke).</jats:p