A Rapid Technique for Counting Cracks in Rocks

Using a scanning electron microscope (SEM) and an image analyzer, we have developed a technique for counting and measuring cracks in rocks which is more efficient than traditional techniques in which an operator performs all image analysis functions. The key aspect of the technique is that black-on-white tracings of fresh cracks, which can be made rather rapidly by an operator, are measured and digitized by an image analyzer. The most time-consuming step in the process has now become the generation of SEM micrographs and pertinent chemical (mineralogical) information, not the quantification of crack structure. The technique has been applied to two studies involving nuclear waste isolation in a granitic rock, Climax Stock (Nevada Test Site) quartz monzonite, a Cretaceous age rock which is structurally very inhomogeneous. One study detected a relationship between crack structure and distance from a hammer-drilled borehole; the other study was unable to detect a relationship between crack structure and gamma irradiation treatment in rocks loaded to near failure

Hydrothermal interaction of solid wafers of Topopah Spring Tuff with J-13 water and distilled water at 90, 150, and 250{sup 0}C, using Dickson-type, gold-bag rocking autoclaves

The Nevada Nuclear Waste Storage Investigations Project has conducted experiments to study the hydrothermal interaction of rock and water representative of a potential high-level waste repository at Yucca Mountain, Nevada. The results of these experiments help define the near-field repository environment during and shortly after the thermal period that results from the emplacement of nuclear waste. When considered in conjunction with results contained in companion reports, these results can be used to assess our ability to accelerate tests using the surface area/volume parameter and/or temperature. These rock-water interaction experiments were conducted with solid polished wafers cut from both drillcore and outcrop samples of Topopah tuff, using both a natural ground water and distilled water as the reacting fluid. Pre- and post-test characterization of the reacting materials was extensive. Post-test identification and chemical analysis of secondary phases resulting from the hydrothermal interactions were aided by using monoliths of tuff rather than crushed material. All experiments were run in Dickson-type, gold-bag rocking autoclaves that were periodically sampled at in situ conditions. A total of nine short-term (up to 66-day) experiments were run in this series; these experiments covered the range from 90 to 250{sup 0}C and from 50 to 100 bar. The results obtained from the experiments have been used to evaluate the modeled results produced by calculations using the geochemical reaction process code EQ3/6. 31 refs., 37 figs., 7 tabs

Hydrothermal Interaction of Topopah Spring Tuff With J-13 Water as a Function of Temperature

In support of the Nevada Nuclear Waste Storage Investigations Project experiments were conducted to study the hydrothermal interaction of rock and water representative of a potential repository in tuff. These experiments provided data relevant to near-field repository conditions that can be used to: assess the ability to use accelerated tests based on the SA/V (surface area/volume) parameter and temperature; allow the measurement of chemical changes in phases present in the tuff before reaction as well as the identification and chemical analysis of secondary phases resulting from hydrothermal reactions; and demonstrate the usefulness of geochemical modeling in a repository environment using the EQ3/6 thermodynamic/kinetic geochemical modeling code. Crushed tuff and polished wafers of tuff were reacted with a natural ground water in Dickson-type gold-cell rocking autoclaves which were periodically sampled under in-situ conditions. Results were compared with predictions based on the EQ3/6 geochemical modeling code. Eight short-term experiments (2 to 3 months) at 150{sup 0}C and 250{sup 0}C have been completed using tuff from both drillcore and outcrop. Long-term experiments at 90{sup 0}C and 150{sup 0}C using drillcore polished wafers are in progress. This paper will focus on the results of the 150{sup 0}C and 250{sup 0}C experiments using drill core polished wafers. 11 references, 4 figures

Report on the feasibility of using isotopes to source and age-date groundwater in Orange County water district`s Forebay region

From March to September 1995, the Isotope Sciences Division of Lawrence Livermore National Laboratory performed isotopic measurements on water in the Orange County Forebay region. The goal was to test the applicability of isotope techniques for determining the current groundwater flow paths and flow rates in the OCWD spreading facilities. Successful results could then be used to predict the fate of proposed reclaimed waste water recharge. Stable isotope measurements in surface waters and groundwaters in the Forebay region of the Orange County groundwater basin provided a general source indicator. The data defined three general groups: (1) groundwater derived from recharged Santa Ana River water (SAR),(2) groundwater resulting from a mixture of recharged Colorado River water and the SAR, and (3) groundwater recharged from the Santiago basin area. In the first group of data, recharge directly from the SAR flow was not readily distinguishable from groundwater recharged via the spreading ponds. Some groundwater samples from Forebay wells showed significant temporal variability in stable isotope values, while others remained constant throughout the study period. The temporal changes in the groundwater stable isotope signatures are believed to be controlled by similar variations in the stable isotope signatures of the surface water recharge. With further sampling, these seasonal isotopic variations may provide a viable tracer for young (<2 years) groundwater

The waveform correlation event detection system project, Phase I: Issues in prototype development and testing

A study using long-period seismic data showed that seismic events can be detected and located based on correlations of processed waveform profiles with the profile expected for an event. In this technique both time and space are discretized and events are found by forming profiles and calculating correlations for all time-distance points. events are declared at points with large correlations. In the first phase of the Waveform Correlation Event Detection System (WCEDS) Project at Sandia Labs we have developed a prototype automatic event detection system based on Shearer`s work which shows promise for treaty monitoring applications. Many modifications have been made to meet the requirements of the monitoring environment. A new full matrix multiplication has been developed which can reduce the number of computations needed for the data correlation by as much as two orders of magnitude for large grids. New methodology has also been developed to deal with the problems caused by false correlations (sidelobes) generated during the correlation process. When an event has been detected, masking matrices are set up which will mask all correlation sidelobes due to the event, allowing other events with intermingled phases to be found. This process is repeated until a detection threshold is reached. The system was tested on one hour of Incorporated Research Institutions for Seismology (IRIS) broadband data and built all 4 of the events listed in the National Earthquake Information Center (NEIC) Preliminary Determination of Epicenters (PDE) which were observable by the IRIS network. A continuous execution scheme has been developed for the system but has not yet been implemented. Improvements to the efficiency of the code are in various stages of development. Many refinements would have to be made to the system before it could be used as part of an actual monitoring system, but at this stage we know of no clear barriers which would prevent an eventual implementation of the system

Outcomes Following Abiraterone versus Enzalutamide for Prostate Cancer: A Scoping Review

Abiraterone acetate (AA) and enzalutamide (ENZ) are commonly used for metastatic prostate cancer. It is unclear how their outcomes and toxicities vary with patient-specific factors because clinical trials typically exclude patients with significant comorbidities. This study aims to fill this knowledge gap and facilitate informed treatment decision making. A registered protocol utilizing PRISMA scoping review methodology was utilized to identify real-world studies. Of 433 non-duplicated publications, 23 were selected by three independent reviewers. ENZ offered a faster and more frequent biochemical response (30-50% vs. 70-75%), slowed progression (HR 0.66; 95% CI 0.50-0.88), and improved overall survival versus AA. ENZ was associated with more fatigue and neurological adverse effects. Conversely, AA increased risk of cardiovascular- (HR 1.82; 95% CI 1.09-3.05) and heart failure-related (HR 2.88; 95% CI 1.09-7.63) hospitalizations. Ultimately, AA was associated with increased length of hospital stay, emergency department visits, and hospitalizations (HR 1.26; 95% CI 1.04-1.53). Accordingly, total costs were higher for AA, although pharmacy costs alone were higher for ENZ. Existing data suggest that AA and ENZ have important differences in outcomes including toxicities, response, disease progression, and survival. Additionally, adherence, healthcare utilization, and costs differ. Further investigation is warranted to inform treatment decisions which optimize patient outcomes

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD\u27s rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions

Mineralogic and petrologic investigation of post-test core samples from the Spent Fuel Test - Climax

We have characterized a suite of samples taken subsequent to the end of the Spent Fuel Test - Climax by petrographic and microanalytical techniques and determined their mineral assemblage, modal properties, and mineral chemistry. The samples were obtained immediately adjacent to the canister borehole at a variety of depths and positions within the canister drift, as well as radially outward from each canister hole. This method of sampling allows variations in post-test mineralogic properties to be evaluated on the basis of (1) depth along a particular canister hole and (2) position within the canister drift, with respect to the heat and radiation sources, and with respect to the pre - test samples. In no case did we find any significant correlation between the mineralogical properties and variables listed above. In short, the Spent Fuel Test - Climax has produced no identifiable mineralogical response in the Climax quartz monzonite. 12 refs., 11 figs., 5 tabs

Permeability of stemming materials for prompt gas sampling

The permeability and porosity of a suite of man-made granular aggregates and stemming materials currently in use at NTS was measured in 1-D loading as a function of stress. In all cases, the gas permeability was measured at 22 MPa after cycling up and down from 100 to 1200 MPa. Depending on stress and material, permeability decreased up to three orders of magnitude, porosity up to 63% and the sample compacted by as much as 35%. Steel ball bearings were found to retain the highest permeability of all the materials tested. The enhancement of prompt gas sampling through alternate stemming material in the column above the nuclear device is discussed