Yucca Mountain Site Characterization Project exploratory studies facilities construction status

International Nuclear Information System (INIS)

Allan, J.N.; Leonard, T.M.

1993-01-01

This paper discusses the progress to date on the construction planning and development of the Yucca Mountain Site Characterization Project (YMP) Exploratory Studies Facilities (ESF). The purpose of the ESF is to determine early site suitability and to characterize the subsurface of the Yucca Mountain site to assess its suitability for a potential high level nuclear waste repository. The present ESF configuration concept is for two main ramps to be excavated by tunnel boring machines (TBM) from the surface to the Topopah Spring Member of the Paintbrush Tuff Formation. From the main ramps, slightly above Topopah Spring level, supplemental ramps will be penetrated to the Calico Hills formation below the potential repository. There will be exploratory development drifts driven on both levels with the Main Test Area being located on the Topopah Spring level, which is the level of the proposed repository. The Calico Hills formation lies below the Topopah Spring member and is expected to provide the main geo-hydrologic barrier between the potential repository and the underlying saturated zones in the Crater Flat Tuff

Intracrystalline diffusion in clinoptilolite: Implications for radionuclide isolation

International Nuclear Information System (INIS)

Roberts, S.K.; Viani, B.E.; Phinney, D.

1995-01-01

Experiments have been performed to measure the rate of exchange diffusion in the zeolite clinoptilolite (CL) for elements important to radionuclide isolation at Yucca Mountain, NV. Clinoptilolite is one of the major sorptive minerals in the tuffs at Yucca Mountain, and occurs both as a major component in zeolitized units (Calico Hills), and in fractures in non-zeolitized tuffs (Topopah Spring). Field evidence and numerical modeling suggests that the movement of fluids through the tuff rocks adjacent to the potential repository may occur via episodic flow through fractures. Under conditions of rapid fracture flow the effective sorptive capacity of fracture-lining clinoptilolite may be controlled by exchange diffusion rather than exchange equilibrium

A probabilistic approach to rock mechanical property characterization for nuclear waste repository design

International Nuclear Information System (INIS)

Kim, Kunsoo; Gao, Hang

1996-01-01

A probabilistic approach is proposed for the characterization of host rock mechanical properties at the Yucca Mountain site. This approach helps define the probability distribution of rock properties by utilizing extreme value statistics and Monte Carlo simulation. We analyze mechanical property data of tuff obtained by the NNWSI Project to assess the utility of the methodology. The analysis indicates that laboratory measured strength and deformation data of Calico Hills and Bullfrog tuffs follow an extremal. probability distribution (the third type asymptotic distribution of the smallest values). Monte Carlo simulation is carried out to estimate rock mass deformation moduli using a one-dimensional tuff model proposed by Zimmermann and Finley. We suggest that the results of these analyses be incorporated into the repository design

Summary of lithologic logging of new and existing boreholes at Yucca Mountain, Nevada, March 1994 to June 1994

International Nuclear Information System (INIS)

Geslin, J.K.; Moyer, T.C.

1995-01-01

This report summarizes lithologic logging of core from boreholes at Yucca Mountain, Nevada, conducted from March 1994 to June 1994. Units encountered during logging include Quaternary-Tertiary alluvium and colluvium, Tertiary Rainier Mesa Tuff, all units in the Tertiary Paintbrush Group, and Tertiary Calico Hills Formation. Logging results are presented in a table of contact depths for core from unsaturated zone neutron (UZN) boreholes and graphic lithologic logs for core from north ramp geology (NRG) boreholes

Summary of lithologic logging of new and existing boreholes at Yucca Mountain, Nevada, August 1993 to February 1994

Energy Technology Data Exchange (ETDEWEB)

Geslin, J.K.; Moyer, T.C.; Buesch, D.C.

1995-05-01

Yucca Mountain, Nevada, is being investigated as a potential site for a high-level radioactive waste repository. This report summarizes the lithologic logging of new and existing boreholes at Yucca Mountain that was done from August 1993 to February 1994 by the Rock Characteristics Section, Yucca Mountain Project Branch, US Geological Survey (USGS). Units encountered during logging include Quaternary-Tertiary alluvium/colluvium, Tertiary Rainier Mesa Tuff, all units in the Tertiary Paintbrush Group, Tertiary Calico Hills Formation and Tertiary Prow Pass Tuff. We present criteria used for recognition of stratigraphic contacts, logging results as tables of contact depths for core from neutron (UZN) boreholes and graphical lithologic logs for core from non-UZN boreholes, and descriptions of several distinctive nonwelded tuffs recognized in the PTn hydrogeologic unit of the Paintbrush Group.

Summary of lithologic logging of new and existing boreholes at Yucca Mountain, Nevada, August 1993 to February 1994

International Nuclear Information System (INIS)

Geslin, J.K.; Moyer, T.C.; Buesch, D.C.

1995-01-01

Yucca Mountain, Nevada, is being investigated as a potential site for a high-level radioactive waste repository. This report summarizes the lithologic logging of new and existing boreholes at Yucca Mountain that was done from August 1993 to February 1994 by the Rock Characteristics Section, Yucca Mountain Project Branch, US Geological Survey (USGS). Units encountered during logging include Quaternary-Tertiary alluvium/colluvium, Tertiary Rainier Mesa Tuff, all units in the Tertiary Paintbrush Group, Tertiary Calico Hills Formation and Tertiary Prow Pass Tuff. We present criteria used for recognition of stratigraphic contacts, logging results as tables of contact depths for core from neutron (UZN) boreholes and graphical lithologic logs for core from non-UZN boreholes, and descriptions of several distinctive nonwelded tuffs recognized in the PTn hydrogeologic unit of the Paintbrush Group

Busted Butte Phase 2: Analysis of Post-Test Mineback and Overcore Rock Samples

International Nuclear Information System (INIS)

Turin, H.J.; McGraw, M.A.; Jones, C.L.; Scism, C.D.; Soll, W.E.

2002-01-01

A complex tracer mixture was injected continuously for over two years into a 10 x 10 x 7 m block of tuff as part of the unsaturated-zone (UZ) tracer test at Busted Butte. The test was designed to address uncertainties associated with flow and transport models within the Topopah Springs and Calico Hills tuffs. The tracer mixture included nonreactive (Br, I, and FBAs) and reactive tracers (Li, Ce, Sm, Ni, Coy and Mn) and synthetic colloids. Once injection was completed, samples from the block were collected in two ways. Overcores were taken from around and below injection holes. Then, the entire block was excavated via mineback--during which progressive vertical planes of the block were exposed. Samples from the overcores and mineback were analyzed to determine the distribution of tracers on different spatial scales than available from collection borehole data. Rock analyses confirmed collection pad results that the nonreactive tracers, Br and FBAs, moved several meters. Furthermore, Br and FBAs are observed above and lateral to the injector planes suggesting that capillarity was an important process for tracer movement. Lithium, the most mobile of the metals, was transported on a scale of meters. This is consistent with laboratory sorption measurements and observed breakthrough on the collection pads. Co and Ni show transport distances of tens of cm, while Sm and Ce moved far less, possibly due to precipitation and sorption effects. Colloid transport was assessed using 1 ft3 blocks extracted from the BB Phase 2 block. In the Calico Hills material, after 15 L of water was injected over 3.5 months, less than 1% of the colloids injected were recovered. Flow patterns in the block indicate that water injected at the center imbibed outward from the injection point. In a block taken from a boundary of the Calico Hills ashfall layer, breakthrough was observed only due to fractures formed during drying of the block. The colloid transport module for FEHM was tested against

A strategy to seal exploratory boreholes in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Givens, C.A.; Carney, B.C.

1994-04-01

This report presents a strategy for sealing exploratory boreholes associated with the Yucca Mountain Site Characterization Project. Over 500 existing and proposed boreholes have been considered in the development of this strategy, ranging from shallow (penetrating into alluvium only) to deep (penetrating into the groundwater table). Among the comprehensive list of recommendations are the following: Those boreholes within the potential repository boundary and penetrating through the potential repository horizon are the most significant boreholes from a performance standpoint and should be sealed. Shallow boreholes are comparatively insignificant and require only nominal sealing. The primary areas in which to place seals are away from high-temperature zones at a distance from the potential repository horizon in the Paintbrush nonwelded tuff and the upper portion of the Topopah Spring Member and in the tuffaceous beds of the Calico Hills Unit. Seals should be placed prior to waste emplacement. Performance goals for borehole seals both above and below the potential repository are proposed. Detailed construction information on the boreholes that could be used for future design specifications is provided along with a description of the environmental setting, i.e., the geology, hydrology, and the in situ and thermal stress states. A borehole classification scheme based on the condition of the borehole wall in different tuffaceous units is also proposed. In addition, calculations are presented to assess the significance of the boreholes acting as preferential pathways for the release of radionuclides. Design calculations are presented to answer the concerns of when, where, and how to seal. As part of the strategy development, available technologies to seal exploratory boreholes (including casing removal, borehole wall reconditioning, and seal emplacement) are reviewed

Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995

Energy Technology Data Exchange (ETDEWEB)

Luckey, R.R.; Tucci, P.; Faunt, C.C.; Ervin, E.M. [and others

1996-12-31

Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data.

Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995

International Nuclear Information System (INIS)

Luckey, R.R.; Tucci, P.; Faunt, C.C.; Ervin, E.M.

1996-01-01

Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data

Geohydrologic data and models of Rainier Mesa and their implications to Yucca Mountain

International Nuclear Information System (INIS)

Wang, J.S.Y.; Cook, N.G.W.; Wollenberg, H.A.; Carnahan, C.L.; Javandel, I.; Tsang, C.F.

1993-01-01

The geohydrologic data collected at Rainier Mesa provide the only extensive observations in tunnels presently available on flow and transport in tuff units similar to those of a potential nuclear waste repository at Yucca Mountain. This information can, therefore, be of great value in planning the Exploratory Studies Facility (ESF) testing in underground drifts at Yucca Mountain. In this paper, we compare the geohydrologic characteristics of tuff units of these two sites and summarize the hydrochemical data indicating the presence of nearly meteoric water in Rainier Mesa tunnels. A simple analytic model is used to evaluate the possibility of propagating transient pulses of water along fractures or faults through the Paintbrush nonwelded tuff unit to reach the tunnel beds below. The results suggest that fast flow could occur without significant mixing between meteoric fracture water and matrix pore water. The implications of these findings on planning for the ESF Calico Hills study at Yucca Mountain are discussed

Disruption scenarios for a high-level waste repository at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Ross, B.

1986-01-01

A high-level waste repository located in unsaturated welded tuff at Yucca Mountain, Nevada, would rely on six different, although not entirely independent, barriers to prevent escape of radioactivity. These barriers are the waste canister, fuel cladding, slow dissolution of the spent fuel itself, and slow movement of released contaminants in three different hydrogeologic units: the unsaturated Topopah Spring welded tuff unit, the unsaturated Calico Hills nonwelded tuff unit, and the saturated tuff aquifer. Fifty-eight processes and events that might affect such a repository were reviewed. Eighty-three different sequences were identified by which these processes and events could lead to failure of one or more barriers. Sequences which had similar consequences were grouped, yielding 17 categories. The repository system has considerable redundancy; most of the more likely disruptions affect only one or a few barriers. Occurrence of more than one disruption is needed before such disruptions would cause release of radioactivity. Future studies of repository performance must assess the likelihood and consequences of multiple-disruption scenarios to evaluate how well the repository meets performance standards

A strategy to seal exploratory boreholes in unsaturated tuff; Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.A. [Sandia National Labs., Albuquerque, NM (United States); Case, J.B.; Givens, C.A.; Carney, B.C. [IT Corp., Albuquerque, NM (United States)

1994-04-01

This report presents a strategy for sealing exploratory boreholes associated with the Yucca Mountain Site Characterization Project. Over 500 existing and proposed boreholes have been considered in the development of this strategy, ranging from shallow (penetrating into alluvium only) to deep (penetrating into the groundwater table). Among the comprehensive list of recommendations are the following: Those boreholes within the potential repository boundary and penetrating through the potential repository horizon are the most significant boreholes from a performance standpoint and should be sealed. Shallow boreholes are comparatively insignificant and require only nominal sealing. The primary areas in which to place seals are away from high-temperature zones at a distance from the potential repository horizon in the Paintbrush nonwelded tuff and the upper portion of the Topopah Spring Member and in the tuffaceous beds of the Calico Hills Unit. Seals should be placed prior to waste emplacement. Performance goals for borehole seals both above and below the potential repository are proposed. Detailed construction information on the boreholes that could be used for future design specifications is provided along with a description of the environmental setting, i.e., the geology, hydrology, and the in situ and thermal stress states. A borehole classification scheme based on the condition of the borehole wall in different tuffaceous units is also proposed. In addition, calculations are presented to assess the significance of the boreholes acting as preferential pathways for the release of radionuclides. Design calculations are presented to answer the concerns of when, where, and how to seal. As part of the strategy development, available technologies to seal exploratory boreholes (including casing removal, borehole wall reconditioning, and seal emplacement) are reviewed.

Unit evaluation at Yucca Mountain, Nevada Test Site: summary report and recommendation

International Nuclear Information System (INIS)

Johnstone, J.K.; Peters, R.R.; Gnirk, P.F.

1984-06-01

Of the four potential repository units, identified at Yucca Mountain, two potential units the welded, devitrified portions of the Bullfrog and Tram Members of the Crater Flat Tuff are below the water table. The welded, devitrified Topopah Spring Member of the Paintbrush Tuff and the nonwelded, zeolitized Tuffaceous Beds of Calico Hills are above the water table. The results of a study of the four potential repository units are to provide a technical basis for selecting a single target repository unit for future test and evaluation. The unit evaluation studies compared the units rather than provided and absolute assessment. The four ranking evaluation criteria used were: radionuclide isolation time; allowable repository gross thermal loading; excavation stability; and relative economics. Considered the most important of the criteria as well as the most difficult, radionuclide isolation times were estimated using the limited existing data. The allowable repository gross thermal loadings determined from near-field calculations, were nearly the same for all four units. The gross thermal loading supported other criteria by providing the heat source for succeeding thermally related evaluation studies. A large number of studies evaluated excavation stability, including near-field mechanical and thermomechanical finite element code calculations studies. A large number of studies evaluated excavation stability, including near-field mechanical and thermomechanical finite element code calculations, rock matrix property evaluation, and rock mass classification. Relative economics, a minor criterion, did not play an explicit role in the final ranking. Based on all of the analyses, the final recommendation was that the Topopah Springs be selected as the target unit, followed, in order, by the Calico Hills, Bullfrog, and Tram

75 FR 65650 - Notice of Availability of the Record of Decision for the Calico Solar Project and Associated...

Science.gov (United States)

2010-10-26

... Calico Solar Project into the Energy Production and Utility Corridors Element of the CDCA Plan. The BLM's..., the BLM is also amending the CDCA Plan to allow for the siting of a solar energy power plant on the..., LVRAM109AA03] Notice of Availability of the Record of Decision for the Calico Solar Project and Associated...

A first look at roadheader construction and estimating techniques for site characterization at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Neil, D.M.; Taylor, D.L.

1991-01-01

The Yucca Mountain site characterization program will be based on mechanical excavation techniques for the mined repository construction and development. Tunnel Boring Machines (TBM's), Mobile Miners (MM), Raiseborers (RB), Blind Hole Shaft Boring Machines (BHSB), and Roadheaders (RH) have been selected as the mechanical excavation machines most suited to mine the densely welded and non-welded tuffs of the Topopah Springs and Calico Hills members. Heavy duty RH in the 70 to 100 ton class with 300 Kw cutter motors have been evaluated and formulas developed to predict machine performance based on the rock physical properties and the results of Linear Cutting Machine (LCM) tests done at the Colorado School of Mines (CSM) for Sandia National Labs. (SNL)

Preliminary report on the geology and geophysics of drill hole UE25a-1, Yucca Mountain, Nevada Test Site

International Nuclear Information System (INIS)

Spengler, R.W.; Muller, D.C.; Livermore, R.B.

1979-01-01

A subsurface geologic study in connection with the Nevada Nuclear Waste Storage Investigations has furnished detailed stratigraphic and structural information about tuffs underlying northeastern Yucca Mountain on the Nevada Test Site. Drill hole UE25a-1 penetrated thick sequences of nonwelded to densely welded ash-flow and bedded tuffs of Tertiary age. Stratigraphic units that were identified from the drill-hole data include the Tiva Canyon and Topopah Spring Members of the Paintbrush Tuff, tuffaceous beds of Calico Hills, and the Prow Pass and Bullfrog Members of the Crater Flat Tuff. Structural analysis of the core indicated densely welded zones to be highly fractured. Many fractures show near-vertical inclinations and are commonly coated with secondary silica, manganese and iron oxides, and calcite. Five falt zones were recognized, most of which occurred in the Topopah Spring Member. Shear fractures commonly show oblique-slip movement and some suggest a sizable component of lateral compression. Graphic logs are included that show the correlation of lithology, structural properties, and geophysical logs. Many rock units have characteristic log responses but highly fractured zones, occurring principally in the Tiva Canyon and Topopah Spring Members restricted log coverage to the lower half of the drill hole

Bulk and mechanical properties of the Paintbrush tuff recovered from borehole USW NRG-7/7A: Data report. Yucca Mountain Site Characterization Project

International Nuclear Information System (INIS)

Martin, R.J.; Boyd, P.J.; Noel, J.S.; Price, R.H.

1995-05-01

An integral part of the licensing procedure for the potential nuclear waste repository at Yucca Mountain, Nevada, involves prediction of the in situ rheology for the design and construction of the facility and the emplacement of canisters containing radioactive waste. The data used to model the thermal and mechanical behavior of the repository and surrounding lithologies include dry and saturated bulk densities, average grain density, porosity, compressional and shear wave velocities, elastic moduli, and compressional and tensional fracture strengths. In this study, a suite of experiments was performed on cores recovered from the USW NRG-717A borehole drilled in support of the Exploratory Studies Facility (ESF) at Yucca Mountain. USW NRG-7/7A was drilled to a depth of 1,513.4 feet through five thermal/mechanical units of Paintbrush tuff and terminating in the tuffaceous beds of the Calico IEUS. The thermal/mechanical stratigraphy was defined by Orfiz et al. to group rock horizons of similar properties for the purpose of simplifying modeling efforts. The relationship between the geologic stratigraphy and the thermal/mechanical stratigraphy is presented. The tuff samples in this study have a wide range of welding characteristics, and a smaller range of mineralogy and petrology characteristics. Generally, the samples are silicic, ash-fall tuffs that exhibit large variability in their elastic and strength properties

Preliminary results of gravity investigations at Yucca Mountain and vicinity, Southern Nye County, Nevada

International Nuclear Information System (INIS)

Snyder, D.B.; Carr, W.J.

1982-01-01

Exploration for a high-level-nuclear-waste-repository site in the Yucca Mountain area, Nevada, resulted in the addition of 423 new gravity stations during the past 2 years to the 934 existing stations to form the data base of this study. About 100 surface-rock samples, three borehole gamma-gamma logs, and one borehole gravity study provide excellent density control. A linear increase in density of 0.26 g/cm 3 per km is indicated in the tuff sequences makes the density contrast across the basal contact of the tuff the only strong source of gravity fluctuations. Isostatic and 2.0g/cm 3 Bouguer corrections were applied to the observed gravity values to remove deep-crust-related regional gradients and topographic effects, respectively. The resulting residual-gravity plot shows significant gravity anomalies that correlate closely with the structures inferred from drill-hole and surface geologic studies. Gravity highs over the three Paleozoic rock outcrops within the study area - Bare Mountain, the Calico Hills, and the Striped Hills - served as reference points for the gravity models. At least 3000 m of tuff fills a large steep-sided depression in the prevolcanic rocks beneath Yucca Mountain and Crater Flat. The gravity low and thick tuff section probably lie within a large collapse area comprising the Crater Flat-Timber Mountain-Silent Canyon caldera complexes. Gravity lows in Crater Flat itself are thought to coincide with the source areas of the Prow Pass Member, the Bullfrog Member, and the unnamed member of the Crater Flat Tuff. Southward extension of the broad gravity low associated with Crater Flat into the Amargosa Desert is evidence for sector graben-type collapse segments related to the Timber Mountain caldera and superimposed on the other structures within Crater Flat. 13 figures, 4 tables

Results and interpretation of preliminary aquifer tests in boreholes UE-25c number-sign 1, UE-25c number-sign 2, and UE-25c number-sign 3, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Geldon, A.L.

1996-01-01

Pumping and injection tests conducted in 1983 and 1984 in boreholes UE-25c number-sign 1, UE-25c number-sign 2, and UE-25c number-sign 3 (the c-holes) at Yucca Mountain, Nevada, were analyzed with respect to information obtained from lithologic and borehole geophysical logs, core permeameter tests, and borehole flow surveys. The three closely spaced c-holes, each of which is about 3,000 feet deep, are completed mainly in nonwelded to densely welded, ash-flow tuff of the tuffs and lavas of Calico Hills and the Crater Flat Tuff of Miocene age. Below the water table, tectonic and cooling fractures pervade the tuffaceous rocks but are distributed mainly in 11 transmissive intervals, many of which also have matrix permeability. Information contained in this report is presented as part of ongoing investigations by the US Geological Survey (USGS) regarding the hydrologic and geologic suitability of Yucca Mountain, Nevada, as a potential site for the storage of high-level nuclear waste in an underground mined geologic repository. This investigation was conducted in cooperation with the US Department of Energy under Interagency Agreement DE-AI08-78ET44802, as part of the Yucca Mountain Site Characterization Project

Interpretation of chemical and isotopic data from boreholes in the unsaturated zone at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Yang, I.C.; Rattray, G.W.; Yu, P.

1996-01-01

Analyses of pore water from boreholes at Yucca Mountain indicate that unsaturated-zone pore water has significantly larger concentrations of chloride and dissolved solids than the saturated-zone water or perched-water bodies. Chemical compositions are of the calcium sulfate or calcium chloride types in the Paintbrush Group (Tiva Canyon, Yucca Mountain, Pah Canyon, and bedded tuffs), and sodium carbonate or bicarbonate type water in the Calico Hills Formation. Tritium profiles from boreholes at Yucca Mountain indicate tritium-concentration inversions (larger tritium concentrations are located below the smaller tritium concentration in a vertical profile) occur in many places. These inversions indicate preferential flow through fractures. Rock-gas compositions are similar to that of atmospheric air except that carbon dioxide concentrations are generally larger than those in the air. The delta carbon-13 values of gas are fairly constant from surface to 365.8 meters, indicating little interaction between the gas CO 2 and caliche in the soil. Model calculations indicate that the gas transport in the unsaturated zone at Yucca Mountain agrees well with the gas-diffusion process. Tritium-modeling results indicate that the high tritium value of about 100 tritium units in the Calico Hills Formation of UZ-16 is within limits of a piston-flow model with a water residence time of 32 to 35 years. The large variations in tritium concentrations with narrow peaks imply piston flow or preferential fracture flow rather than matrix flow. In reality, the aqueous-phase flow in the unsaturated zone is between piston and well-mixed flows but is closer to a piston flow

Evaluation of geochemical properties used in area-to-location screening for a nuclear waste repository at the Nevada Test Site

International Nuclear Information System (INIS)

Purson, J.D.

1983-03-01

The area-to-location screening of a potential site for a nuclear waste repository is dependent on geologic compatibility. Specifically, the geochemical properties of candidate locations are significant in the overall site evaluation. This report describes three geochemical factors or attributes and their application to an area-to-location screening of the southwestern quadrant of the Nevada Test Site and contiguous areas. These are only 3 of 31 attributes examined in the screening process. Geochemical and rock media considerations relevant to site screening include: (1) retardation by hydraulics - a study of ground-water movement through fractures vs a permeable matrix; (2) thermal stability of minerals - a measurement of undesirable mineral assemblages in the rock; and (3) retardation by sorption - an evaluation of the total sorptive capacity at a location, based on stratigraphy and lithology. Twelve potential host rocks situated in 20 locations are examined; 2 of these have consistently fewer favorable characteristics, and 6 others have generally fewer favorable characteristics than the 4 remaining rock units. The four units that appear most favorable by geochemical measures are the tuffaceous beds of Calico Hills, granite intrusives, the densely welded Topopah Spring tuff, and the Crater Flat Tuff at Yucca Mountain

A Conceptual Overview of the History of the CALICO Journal: The Phases of CALL

Science.gov (United States)

Fischer, Robert

2013-01-01

Over the 30-year history of the "CALICO Journal", various areas of research and development in CALL have come to the fore in articles published in the journal at different points in time. These areas, which reflect the general concerns of the profession, can be conveniently categorized under the general acronym of ICT: Information and…

Petrographic and Geochemical Analyses of Kirana Hills Shield Rocks around Sargodha and Economic Potential

Directory of Open Access Journals (Sweden)

Muhammad Waseem Khan

2017-04-01

Full Text Available The present study deals with geochemical and petrographic analysis of the Kirana Hill shield rocks of Punjab plains from Buland, Hachi, Shaheen Abad, Shaikh and Machh hills. On basis of the current studies certain modifications have been made in the classification and nomenclature of rocks exposed in the study areas. Chemical analyses have also been carried out in order to calculate Cross Iddings, Pirsson, and Washington (CIPW norms”, to strengthen nomenclature scheme and finally rocks are classified by using “MAGMA SOFTWARE”. Rhyolites predominate over the basalts/dolerites, andesites, and phyllite/ slate. Rhyolitic rocks are light grey, greenish grey and light brown in color, aphanitic in nature. The observed microscopic textures are aphyric, phyric or porphyritic and micropoikilitc. Moreover, some rhyolitic rocks also show flow texture. They are either cryptocrystalline to microcrystalline or microcrystalline to cryptocrystalline. No glassy material has been observed in any thin section. Mafic rocks are characterized by the presence of ferromagnesian minerals with plagioclase. Andesites exhibit mainly porphyritic texture, but aphyric texture has also been observed in few samples. Hydrothermal alterations are also very common in these rocks. Other rock assemblages identified during laboratory studies from Kirana area include: tuffs i.e. (Lithic Crystal Tuff and Lithic Tuff, basaltic andesite, rhyodacite/ dacite, slate/ phyllite, ankeritic rocks/ veins and quartzofeldspathic veins. Our studies also reveal that no evidence of quartzite has been found in the samples collected from above mentioned areas of Kirana, although it has been reported in previous literature. Iron (Fe has been observed in rhyolite as well as other volcanic rocks of Kirana hills, its presence suggests magma from deep mantle instead of crustal melting / anatexis. In the present analysis some primary and secondary copper minerals including chalcopyrite, atacamite and

Preliminary gravity and magnetic models across Midway Valley and Yucca Wash, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Ponce, D.A.; Langenheim, V.E.

1994-01-01

Detailed gravity and ground magnetic data collected along ten traverses across Midway Valley and Yucca Wash on the eastern flank of Yucca Mountain in southwest Nevada are interpreted. These data were collected as part of an effort to evaluate faulting in the vicinity of proposed surface facilities for a potential nuclear waste repository at Yucca Mountain. Geophysical data show that Midway Valley is bounded by large gravity and magnetic anomalies associated with the Bow Ridge and Paintbrush Canyon faults, on the west side of Exile Hill and on the west flank of Fran Ridge, respectively. In addition, Midway Valley itself is characterized by a number of small-amplitude anomalies that probably reflect small-scale faulting beneath Midway Valley. Gravity and magnetic data across the northwest trending Yucca Wash and the inferred Yucca Wash fault indicate no major vertical offsets greater than 100 m using a density contrast of 0.2 to 0.3 g/cm 3 along the proposed Yucca Wash fault. In addition, a broad magnetic high coincides with the approximate location of the hydrologic gradient and probably reflects moderately magnetic Topopah Spring Tuff or lavas in the Calico Hills Formation

Petrology and geochemistry of samples from bed-contact zones in Tunnel Bed 5, U12g-Tunnel, Nevada Test Site

International Nuclear Information System (INIS)

Connolly, J.R.; Keil, K.; Mansker, W.L.; Allen, C.C.; Husler, J.; Lowy, R.; Fortney, D.R.; Lappin, A.R.

1984-10-01

This report summarizes the detailed geologic characterization of samples of bed-contact zones and surrounding nonwelded bedded tuffs, both within Tunnel Bed 5, that are exposed in the G-Tunnel complex beneath Rainier Mesa on the Nevada Test Site (NTS). Original planning studies treated the bed-contact zones in Tunnel Bed 5 as simple planar surfaces of relatively high permeability. Detailed characterization, however, indicates that these zones have a finite thickness, are depositional in origin, vary considerably over short vertical and horizontal distances, and are internally complex. Fluid flow in a sequence of nonwelded zeolitized ash-flow or bedded tuffs and thin intervening reworked zones appears to be a porous-medium phenomenon, regardless of the presence of layering. There are no consistent differences in either bulk composition or detailed mineralogy between bedded tuffs and bed-contact zones in Tunnel Bed 5. Although the original bulk composition of Tunnel Bed 5 was probably peralkaline, extensive zeolitization has resulted in a present peraluminous bulk composition of both bedded tuffs and bed-contact zones. The major zeolite present, clinoptilolite, is intermediate (Ca:K:Na = 26:35:39) and effectively uniform in composition. This composition is similar to that of clinoptilolite from the tuffaceous beds of Calico Hills above the static water level in hole USW G-1, but somewhat different from that reported for zeolites from below the static water level in USW G-2. Tunnel Bed 5 also contains abundant hydrous manganese oxides. The similarity in composition of the clinoptilolites from Tunnel Bed 5 and those above the static water level at Yucca Mountain indicates that many of the results of nuclide-migration experiments in Tunnel Bed 5 would be transferrable to zeolitized nonwelded tuffs above the static water level at Yucca Mountain

Geologic map of the Paintbrush Canyon Area, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Dickerson, R.P.; Drake, R.M. II

1998-01-01

This geologic map is produced to support site characterization studies of Yucca Mountain, Nevada, site of a potential nuclear waste storage facility. The area encompassed by this map lies between Yucca Wash and Fortymile Canyon, northeast of Yucca Mountain. It is on the southern flank of the Timber Mountain caldera complex within the southwest Nevada volcanic field. Miocene tuffs and lavas of the Calico Hills Formation, the Paintbrush Group, and the Timber Mountain Group crop out in the area of this map. The source vents of the tuff cones and lava domes commonly are located beneath the thickest deposits of pyroclastic ejecta and lava flows. The rocks within the mapped area have been deformed by north- and northwest-striking, dominantly west-dipping normal faults and a few east-dipping normal faults. Faults commonly are characterized by well developed fault scarps, thick breccia zones, and hanging-wall grabens. Latest movement as preserved by slickensides on west-dipping fault scarps is oblique down towards the southwest. Two of these faults, the Paintbrush Canyon fault and the Bow Ridge fault, are major block-bounding faults here and to the south at Yucca Mountain. Offset of stratigraphic units across faults indicates that faulting occurred throughout the time these volcanic units were deposited

Geologic map of the Paintbrush Canyon Area, Yucca Mountain, Nevada

Energy Technology Data Exchange (ETDEWEB)

Dickerson, R.P. [Geological Survey, Denver, CO (United States); Drake, R.M. II [Pacific Western Technologies, Ltd., Lakewood, CO (United States)

1998-11-01

This geologic map is produced to support site characterization studies of Yucca Mountain, Nevada, site of a potential nuclear waste storage facility. The area encompassed by this map lies between Yucca Wash and Fortymile Canyon, northeast of Yucca Mountain. It is on the southern flank of the Timber Mountain caldera complex within the southwest Nevada volcanic field. Miocene tuffs and lavas of the Calico Hills Formation, the Paintbrush Group, and the Timber Mountain Group crop out in the area of this map. The source vents of the tuff cones and lava domes commonly are located beneath the thickest deposits of pyroclastic ejecta and lava flows. The rocks within the mapped area have been deformed by north- and northwest-striking, dominantly west-dipping normal faults and a few east-dipping normal faults. Faults commonly are characterized by well developed fault scarps, thick breccia zones, and hanging-wall grabens. Latest movement as preserved by slickensides on west-dipping fault scarps is oblique down towards the southwest. Two of these faults, the Paintbrush Canyon fault and the Bow Ridge fault, are major block-bounding faults here and to the south at Yucca Mountain. Offset of stratigraphic units across faults indicates that faulting occurred throughout the time these volcanic units were deposited.

Structure in continuously cored, deep drill holes at Yucca Mountain, Nevada, with notes on calcite occurrence

International Nuclear Information System (INIS)

Carr, W.J.

1992-12-01

A study of more than 22,000 feet of core from five deep drill holes at Yucca Mountain, Nevada, provided data on the attitude and vertical distribution of faults and fractures, the sense of fault displacement, and the occurrence of calcite. The study was done mainly to look for evidence of fault flattening at depth, but no consistent downward decrease in dip of faults was found, and no increase in strata rotation was evident with increasing depth. In the two drill holes located near prominent faults that dip toward the holes (USW G-3 and G-2), an apparent increase in the frequency of faults occurs below the tuffs and lavas of Calico Hills. Some of this increase occurs in brittle lavas and flow breccias in the lower part of the volcanic section. In the two holes presumed to be relatively removed from the influence of important faults at depth, the vertical distribution of faults is relatively uniform. Calcite occurs mainly in two general zones, voids in welded portions of the Paintbrush Tuff, and in a deeper zone, mostly below 3,500 feet. Calcite is least abundant in USW G-4, which may reflect the fewer faults and fractures encountered in that drill hole

Busted Butte Unsaturated Zone Transport Test: Fiscal Year 1998 Status Report Yucca Mountain Site Characterization Program Deliverable SPU85M4

International Nuclear Information System (INIS)

Bussod, G.Y.; Turin, H.J.; Lowry, W.E.

1999-01-01

This report describes the status of the Busted Butte Unsaturated Zone Transport Test (UZTT) and documents the progress of construction activities and site and laboratory characterization activities undertaken in fiscal year 1998. Also presented are predictive flow-and-transport simulations for Test Phases 1 and 2 of testing and the preliminary results and status of these test phases. Future anticipated results obtained from unsaturated-zone (UZ) transport testing in the Calico Hills Formation at Busted Butte are also discussed in view of their importance to performance assessment (PA) needs to build confidence in and reduce the uncertainty of site-scale flow-and-transport models and their abstractions for performance for license application. The principal objectives of the test are to address uncertainties associated with flow and transport in the UZ site-process models for Yucca Mountain, as identified by the PA working group in February 1997. These include but are not restricted to: (1) The effect of heterogeneities on flow and transport in unsaturated and partially saturated conditions in the Calico Hills Formation. In particular, the test aims to address issues relevant to fracture-matrix interactions and permeability contrast boundaries; (2) The migration behavior of colloids in fractured and unfractured Calico Hills rocks; (3) The validation through field testing of laboratory sorption experiments in unsaturated Calico Hills rocks; (4) The evaluation of the 3-D site-scale flow-and-transport process model (i.e., equivalent-continuum/dual-permeability/discrete-fracture-fault representations of flow and transport) used in the PA abstractions for license application; and (5) The effect of scaling from lab scale to field scale and site scale

Development of waste packages for tuff

International Nuclear Information System (INIS)

Rothman, A.J.

1982-01-01

The objective of this program is to develop nuclear waste packages that meet the Nuclear Regulatory Commission's requirements for a licensed repository in tuff at the Nevada Test Site. Selected accomplishments for FY82 are: (1) Selection, collection of rock, and characterization of suitable outcrops (for lab experiments); (2) Rock-water interactions (Bullfrog Tuff); (3) Corrosion tests of ferrous metals; (4) Thermal modeling of waste package in host rock; (5) Preliminary fabrication tests of alternate backfills (crushed tuff); (6) Reviewed Westinghouse conceptual waste package designs for tuff and began modification for unsaturated zone; and (7) Waste Package Codes (BARIER and WAPPA) now running on our computer. Brief discussions are presented for rock-water interactions, corrosion tests of ferrous metals, and thermal and radionuclide migration modelling

Preliminary thermal expansion screening data for tuffs

International Nuclear Information System (INIS)

Lappin, A.R.

1980-03-01

A major variable in evaluating the potential of silicic tuffs for use in geologic disposal of heat-producing nuclear wastes is thermal expansion. Results of ambient-pressure linear expansion measurements on a group of tuffs that vary treatly in porosity and mineralogy are presente here. Thermal expansion of devitrified welded tuffs is generally linear with increasing temperature and independent of both porosity and heating rate. Mineralogic factors affecting behavior of these tuffs are limited to the presence or absence of cristobalite and altered biotite. The presence of cristobalite results in markedly nonlinear expansion above 200 0 C. If biotite in biotite-hearing rocks alters even slightly to expandable clays, the behavior of these tuffs near the boiling point of water can be dominated by contraction of the expandable phase. Expansion of both high- and low-porosity tuffs containing hydrated silicic glass and/or expandable clays is complex. The behavior of these rocks appears to be completely dominated by dehydration of hydrous phases and, hence, should be critically dependent on fluid pressure. Valid extrapolation of the ambient-pressure results presented here to depths of interest for construction of a nuclear-waste repository will depend on a good understanding of the interaction of dehydration rates and fluid pressures, and of the effects of both micro- and macrofractures on the response of tuff masss

Frictional properties of jointed welded tuff

International Nuclear Information System (INIS)

Teufel, L.W.

1981-07-01

The results of the experiments on simulated joints in welded tuff from the Grouse Canyon Member of the Belted Range Tuff warrant the following conclusions: (1) The coefficient of friction of the joints is independent of normal stress at a given sliding velocity. (2) The coefficient of friction increases with both increasing time of stationary contact and decreasing sliding velocity. (3) Time and velocity dependence of friction is due to an increase in the real area of contact on the sliding surface, caused by asperity creep. (4) Joints in water-saturated tuff show a greater time and velocity dependence of friction than those in dehydrated tuff. (5) The enhanced time and velocity dependence of friction with water saturation is a result of increased creep at asperity contacts, which is in turn due to a reduction in the surface indentation hardness by hydrolytic weakening and/or stress corrosion cracking

Mechanical excavator performance in Yucca Mountain tuffs

International Nuclear Information System (INIS)

Ozdemir, L.; Hansen, F.D.

1991-01-01

A research effort of four phases is in progress at the Colorado School of Mines. The overall program will evaluate the cutability of welded tuff and other lithologies likely to be excavated at Yucca Mountain in the site characterization process. Several mechanical systems are considered with emphasis given to the tunnel boring machine. The research comprises laboratory testing, linear drag bit and disc cutter tests and potentially large-scale laboratory demonstrations to support potential use of a tunnel boring machine in welded tuff. Preliminary estimates of mechanical excavator performance in Yucca Mountain tuff are presented here. As phases of the research project are completed, well quantified estimates will be made of performance of mechanical excavators in the Yucca Mountain tuffs. 3 refs., 2 tabs

Mechanical excavator performance in Yucca Mountain tuffs

International Nuclear Information System (INIS)

Ozdemir, L.; Hansen, F.D.

1991-01-01

A research effort of four phases is in progress at the Colorado School of Mines. The overall program will evaluate the cutability of welded tuff and other lithologies likely to be excavated at Yucca Mountain in the site characterization process. Several mechanical systems are considered with emphasis given to the tunnel boring machine. The research comprises laboratory testing, linear drag bit and disc cutter tests, and potentially large-scale lab. demonstrations to support potential use of a tunnel boring machine in welded tuff. Preliminary estimates of mechanical excavator performance in Yucca Mountain tuff are presented here. As phases of the research project are completed, well-quantified estimates will be made of performance of mechanical excavators in the Yucca Mountain tuffs

Geology of the hills in the region of the City of Santiago de Chile: New isotopic constraints

International Nuclear Information System (INIS)

Vergara, M; Lopez-Escobar, I; Palma, J.L; Hickey-Vargas, R

2001-01-01

Geological, geochronological and geochemical data demonstrate that the area where the city of Santiago de Chile is established used to be a huge volcanic field. At present, it is possible to distinguish in the area at least three volcanic cycles, which are geographically superimposed and deeply eroded. The first is Oligocene in age, the second Lower to Middle Miocene and the third is Middle to Upper Miocene. The Oligocene cycle is represented by volcanic and volcanoclastic rocks of the Provincia-San Ramon-Abanico and Conchali belts, and welded tuffs of the San Cristobal and Renca hills. The Lower to Middle Miocene cycle consists of subvolcanic rocks, mostly of basaltic to basaltic-andesite composition, characterized by the presence of clino- and orthopyroxene. The Middle to Upper Miocene cycle is composed predominantly of amphibole-bearing subvolcanic rocks of dacitic composition. The latter are found at the Manquehue hill, which limits the northern part of the city, and the hills at the Rinconada de Conchali. In this communication, we present new Sr-, Nd- and Pb- isotope data obtained from two subvolcanic samples of basaltic composition collected from the San Cristobal hill and at the Santa Lucia hill (Lower to Middle Miocene) and one amphibole-bearing subvolcanic sample of dacitic composition from the Manquehue hill (Middle to Upper Miocene) (au)

Distribution of potentially hazardous phases in the subsurface at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Guthrie, G.D. Jr.; Bish, D.L.; Chipera, S.J.; Raymond, R. Jr.

1995-05-01

Drilling, trenching, excavation of the Exploratory Studies Facility, and other surface and underground-distributing activities have the potential to release minerals into the environment from tuffs at Yucca Mountain, Nevada. Some of these minerals may be potential respiratory health hazards. Therefore, an understanding of the distribution of the minerals that may potentially be liberated during site-characterization and operation of the potential repository is crucial to ensuring worker and public safety. Analysis of previously reported mineralogy of Yucca Mountain tuffs using data and criteria from the International Agency for Research on Cancer (IARC) suggests that the following minerals are of potential concern: quartz, cristobalite, tridymite, opal-CT, erionite, mordenite, and palygorskite. The authors have re-evaluated the three-dimensional mineral distribution at Yucca Mountain above the static water level both in bulk-rock samples and in fractures, using quantitative X-ray powder diffraction analysis. Erionite, mordenite, and palygorskite occur primarily in fractures; the crystalline-silica minerals, quartz, cristobalite, and tridymite are major bulk-rock phases. Erionite occurs in the altered zone just above the lower Topopah Spring Member vitrophyre, and an occurrence below the vitrophyre but above the Calico Hills has recently been identified. In this latter occurrence, erionite is present in the matrix at levels up to 35 wt%. Mordenite and palygorskite occur throughout the vadose zone nearly to the surface. Opal-CT is limited to zeolitic horizons

Natural language solution to a Tuff problem

International Nuclear Information System (INIS)

Langkopf, B.S.; Mallory, L.H.

1984-01-01

A scientific data base, the Tuff Data Base, is being created at Sandia National Laboratories on the Cyber 170/855, using System 2000. It is being developed for use by scientists and engineers investigating the feasibility of locating a high-level radioactive waste repository in tuff (a type of volcanic rock) at Yucca Mountain on and adjacent to the Nevada Test Site. This project, the Nevada Nuclear Waste Storage Investigations (NNWSI) Project, is managed by the Nevada Operations Office of the US Department of Energy. A user-friendly interface, PRIMER, was developed that uses the Self-Contained Facility (SCF) command SUBMIT and System 2000 Natural Language functions and parametric strings that are schema resident. The interface was designed to: (1) allow users, with or without computer experience or keyboard skill, to sporadically access data in the Tuff Data Base; (2) produce retrieval capabilities for the user quickly; and (3) acquaint the users with the data in the Tuff Data Base. This paper gives a brief description of the Tuff Data Base Schema and the interface, PRIMER, which is written in Fortran V. 3 figures

Evaluation of tuff as a medium for a nucolear waste repository: interim status report on the properties of tuff

International Nuclear Information System (INIS)

Johnstone, J.K.; Wolfsberg, K.

1980-07-01

This report is the second in a series of summary briefings to the National Academy of Science's (NAS) Committee on Radioactive Waste Management dealing with feasibility of disposal of heat-producing radioactive waste in silicic tuff. The interim status of studies of tuff properties determined on samples obtained from Yucca Mountain and Rainier Mesa (G-tunnel) located on the Nevada Test Site (NTS) are discussed. In particular, progress is described on resolving issues identified during the first briefing to the NAS which include behavior of water in tuff when heated, the effect of the presence or absence of water and joints on the thermal/physical properties of tuff and the detailed/complex sorptive properties of highly altered and unaltered tuff. Initial correlations of thermal/physical and sorptive properties with the highly variable porosity and mineralogy are described. Three in-situ, at-depth field experiments, one nearly completed and two just getting underway are described. In particular, the current status of mineralogy and petrology, geochemistry, thermal and mechanical, radiation effects and water behavior studies are described. The goals and initial results of a Mine Design Working Group are discussed. Regional factors such as seismicity, volcanism and hydrology are not discussed

Geochemical and Pb, Sr, and O isotopic study of the Tiva Canyon Tuff and Topopah Spring Tuff, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Neymark, L.A.; Marshall, B.D.; Kwak, L.M.; Futa, Kiyoto; Mahan, S.A.

1995-01-01

Yucca Mountain is currently being studied as a potential site for an underground repository for high-level radioactive waste. One aspect of the site characterization studies is an evaluation o the resource potential at Yucca Mountain. Geochemical and isotopic signatures of past alteration of the welded tuffs that underlie Yucca Mountain provide a means of assessing the probability of hydrothermal ore deposits being present within Yucca Mountain. In this preliminary report, geochemical and isotopic measurements of altered Tiva Canyon Tuff and Topopah Spring Tuff collected from fault zones exposed on the east flank of Yucca Mountain and from one drill core are compared to their unaltered equivalents sampled both in outcrop and drill core. The geochemistry and isotopic compositions of unaltered Tiva Canyon Tuff and Topopah Spring Tuff (high-silica rhyolite portions) are fairly uniform; these data provide a good baseline for comparisons with the altered samples. Geochemical analyses indicate that the brecciated tuffs are characterized by addition of calcium carbonate and opaline silica; this resulted in additions of calcium and strontium,increases in oxygen-18 content, and some redistribution of trace elements. After leaching the samples to remove authigenic carbonate, no differences in strontium or lead isotope compositions between altered and unaltered sections were observed. These data show that although localized alteration of the tuffs has occurred and affected their geochemistry, there is no indication of additions of exotic components. The lack of evidence for exotic strontium and lead in the most severely altered tuff samples at Yucca Mountain strongly implies a similar lack of exotic base or precious metals

THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS

International Nuclear Information System (INIS)

R. JONES

2004-01-01

This model report addresses activities described in ''Technical Work Plan for: Near-Field Environment and Transport Thermal Properties and Analysis Reports Integration'' (BSC 2004 [DIRS 171708]). The model develops values for thermal conductivity, and its uncertainty, for the nonrepository layers of Yucca Mountain; in addition, the model provides estimates for matrix porosity and dry bulk density for the nonrepository layers. The studied lithostratigraphic units, as identified in the ''Geologic Framework Model'' (GFM 2000) (BSC 2004 [DIRS 170029]), are the Timber Mountain Group, the Tiva Canyon Tuff, the Yucca Mountain Tuff, the Pah Canyon Tuff, the Topopah Spring Tuff (excluding the repository layers), the Calico Hills Formation, the Prow Pass Tuff, the Bullfrog Tuff, and the Tram Tuff. The deepest model units of the GFM (Tund and Paleozoic) are excluded from this study because no data suitable for model input are available. The parameter estimates developed in this report are used as input to various models and calculations that simulate heat transport through the rock mass. Specifically, analysis model reports that use product output from this report are: (1) Drift-scale coupled processes (DST and TH seepage) models; (2) Drift degradation analysis; (3) Multiscale thermohydrologic model; and (4) Ventilation model and analysis report. In keeping with the methodology of the thermal conductivity model for the repository layers in ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]), the Hsu and others (1995 [DIRS 158073]) three-dimensional (3-D) cubic model (referred to herein as ''the Hsu model'') was used to represent the matrix thermal conductivity as a function of the four parameters (matrix porosity, thermal conductivity of the saturating fluid, thermal conductivity of the solid, and geometric connectivity of the solid). The Hsu model requires input data from each test specimen to meet three specific conditions: (1) Known value

Effect of moisture on tuff stone degradation

NARCIS (Netherlands)

Lubelli, B.A.; Nijland, T.G.

2016-01-01

Tuff stone elements with a large length/width ratio often suffer damage in the form of cracks parallel to the surface and spalling of the outer layer. The response of tuff to moisture might be a reason for this behaviour. This research aimed at verifying if differential dilation between parts with

Stratigraphy, age and environments of the late Miocene Mpesida Beds, Tugen Hills, Kenya.

Science.gov (United States)

Kingston, John D; Fine Jacobs, Bonnie; Hill, Andrew; Deino, Alan

2002-01-01

Interpretations of faunal assemblages from the late Miocene Mpesida Beds in the Tugen Hills of the Central Kenyan Rift Valley have figured prominently in discussions of faunal turnover and establishment of the modern East African communities. These faunal changes have important implications for the divergence of the human lineage from the African apes ca. 8-5 Ma. While fossil material recovered from the Mpesida Beds has traditionally been analyzed collectively, accumulating evidence indicates that Mpesida facies span the 7-6 Ma interval and are scattered more than 25 km along the eastern flanks of the Tugen Hills. Stratigraphic distinctions between Mpesida facies and younger sediments in the sequence, such as the Lukeino Formation, are not yet fully resolved, further complicating temporal assessments and stratigraphic context of Mpesida facies. These issues are discussed with specific reference to exposures of Mpesida facies at Rurmoch, where large fossil tree fragments were swept up in an ancient ash flow. Preserved anatomical features of the fossil wood as well as estimated tree heights suggest a wet, lowland rainforest in this portion of the rift valley. Stable isotopic analyses of fossil enamel and paleosol components indicate the presence of more open habitats locally. Overlying air-fall tuffs and epiclastic debris, possibly associated with the ash flow, have yielded an assemblage of vertebrate fossils including two teeth belonging to one of the earliest colombines of typical body size known from Africa, after the rather small Microcolobus. Single-crystal, laser-fusion,(40)Ar/(39)Ar dates from a capping trachyte flow as well as tuffs just below the lava contact indicate an age of greater than 6.37 Ma for the fossil material. Copyright 2002 Academic Press.

Stratigraphy and structure of volcanic rocks in drill hole USW-G1, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Spengler, R.W.; Byers, F.M. Jr.; Warner, J.B.

1981-01-01

Detailed subsurface studies in connection with the Nevada Nuclear Waste Storage Investigations program are being conducted to investigate the stratigraphic and structural features of volcanic rocks underlying Yucca Mountain, a volcanic highland situated along the western boundary of the Nevada Test Site in southern Nevada. As part of this continuing effort, drill hole USW-G1 was cored from 292 ft to a depth of 6000 ft from March to August 1980. The stratigraphic section is composed of thick sequences of ash-flow tuff and volcanic breccia interbedded with subordinate amounts of fine- to coarse-grained volcaniclastic rocks. All rocks are of Tertiary age and vary in composition from rhyolite to dacite. The 3005-ft level in the drill hole represents a significant demarcation between unaltered and altered volcanic rocks. For the most part, tuff units above 3005 ft appear devitrified and show little secondary alteration except within tuffaceous beds of Calico Hills, where the rock contains 60 to 80% zeolites. Below 3005 ft, most rocks show intermittent to pervasive alteration to clay minerals and zeolites. Examination of core for structural features revealed the presence of 61 shear fractures, 528 joints, and 4 conspicuous fault zones. Shear fractures mainly occurred in the Topopah Spring Member of the Paintbrush Tuff, flow breccia, and near fault zones. Nearly 88% of shear and joint surfaces show evidence of coatings. Approximately 40% of the fractures were categorized as completely healed. Rock quality characteristics as defined by the core index indicate that greater amounts of broken and lost core are commonly associated with (1) the densely welded zone of the Topopah Spring, (2) highly silicified zones, and (3) fault zones

Mechanical characterization of densely welded Apache Leap tuff

International Nuclear Information System (INIS)

Fuenkajorn, K.; Daemen, J.J.K.

1991-06-01

An empirical criterion is formulated to describe the compressive strength of the densely welded Apache Leap tuff. The criterion incorporates the effects of size, L/D ratio, loading rate and density variations. The criterion improves the correlation between the test results and the failure envelope. Uniaxial and triaxial compressive strengths, Brazilian tensile strength and elastic properties of the densely welded brown unit of the Apache Leap tuff have been determined using the ASTM standard test methods. All tuff samples are tested dry at room temperature (22 ± 2 degrees C), and have the core axis normal to the flow layers. The uniaxial compressive strength is 73.2 ± 16.5 MPa. The Brazilian tensile strength is 5.12 ± 1.2 MPa. The Young's modulus and Poisson's ratio are 22.6 ± 5.7 GPa and 0.20 ± 0.03. Smoothness and perpendicularity do not fully meet the ASTM requirements for all samples, due to the presence of voids and inclusions on the sample surfaces and the sample preparation methods. The investigations of loading rate, L/D radio and cyclic loading effects on the compressive strength and of the size effect on the tensile strength are not conclusive. The Coulomb strength criterion adequately represents the failure envelope of the tuff under confining pressures from 0 to 62 MPa. Cohesion and internal friction angle are 16 MPa and 43 degrees. The brown unit of the Apache Leap tuff is highly heterogeneous as suggested by large variations of the test results. The high intrinsic variability of the tuff is probably caused by the presence of flow layers and by nonuniform distributions of inclusions, voids and degree of welding. Similar variability of the properties has been found in publications on the Topopah Spring tuff at Yucca Mountain. 57 refs., 32 figs., 29 tabs

Laboratory studies of radionuclide migration in tuff

International Nuclear Information System (INIS)

Rundberg, R.S.; Mitchell, A.J.; Ott, M.A.; Thompson, J.L.; Triay, I.R.

1989-01-01

The movement of selected radionuclides has been observed in crushed tuff, intact tuff, and fractured tuff columns. Retardation factors and dispersivities were determined from the elution profiles. Retardation factors have been compared with those predicted on the basis of batch sorption studies. This comparison forms a basis for either validating distribution coefficients or providing evidence of speciation, including colloid formation. Dispersivities measured as a function of velocity provide a means of determining the effect of sorption kinetics or mass transfer on radionuclide migration. Dispersion is also being studied in the context of scaling symmetry to develop a basis for extrapolating from the laboratory scale to the field. 21 refs., 6 figs., 2 tabs

Pyritic ash-flow tuff, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Castor, S.B.; Tingley, J.V.; Bonham, H.F. Jr.

1994-01-01

The Yucca Mountain site is underlain by a 1,500-m-thick Miocene volcanic sequence that comprises part of the southwestern Nevada volcanic field. Rocks of this sequence, which consists mainly of ash-flow tuff sheets with minor flows and bedded tuff, host precious metal mineralization in several areas as near as 10 km from the site. In two such areas, the Bullfrog and Bare Mountain mining districts, production and reserves total over 60 t gold and 150 t silver. Evidence of similar precious metal mineralization at the Yucca Mountain site may lead to mining or exploratory drilling in the future, compromising the security of the repository. The authors believe that most of the pyrite encountered by drilling at Yucca Mountain was introduced as pyroclastic ejecta, rather than by in situ hydrothermal activity. Pyritic ejecta in ash-flow tuff are not reported in the literature, but there is no reason to believe that the Yucca Mountain occurrence is unique. The pyritic ejecta are considered by us to be part of a preexisting hydrothermal system that was partially or wholly destroyed during eruption of the tuff units. Because it was introduced as ejecta in tuff units that occur at depths of about 1,000 m, such pyrite does not constitute evidence of shallow mineralization at the proposed repository site; however, the pyrite may be evidence for mineralization deep beneath Yucca Mountain or as much as tens of kilometers from it

Hydrogeology of the unsaturated zone, North Ramp area of the Exploratory Studies Facility, Yucca Mountain, Nevada

Science.gov (United States)

Rousseau, Joseph P.; Kwicklis, Edward M.; Gillies, Daniel C.; Rousseau, Joseph P.; Kwicklis, Edward M.; Gillies, Daniel C.

1999-01-01

descending order, these hydrogeologic units are the Tiva Canyon welded (TCw), Paintbrush nonwelded (PTn), Topopah Spring welded (TSw ), and Calico Hills nonwelded (CHn). Deep percolation takes place as episodic pulses of inflow that propagate rapidly to depth and apparently bypass most of the rock matrix. Field-scale and core-scale water potentials throughout much of the PTn and TSw are very high, generally greater than -0.3 megapascals, and are nearly depth invariant. Thus, the imbibition capacity of the densely welded tuffs, at least near fractures, is very small because of low matrix permeabilities and low water-potential gradients across the fracture-matrix interface. The combination of high fracture permeability, high water potentials, high matrix saturations, and low matrix permeabilities results in a percolation environment that favors deep fracture flow. The episodic pulses of inflow are evidenced in the sporadic but nevertheless commonplace occurrence of water with concentrations of radioactive isotopes indicative of origins postdating the atmospheric testing of nuclear weapons. High concentrations of tritium have been detected at many horizons within the PTn and in the top of the TSw. Much lower concentrations of tritium, indicating the mixing of a bomb-pulse component with older water, have been detected in the deeper sections of the TSw and in the CHn. Evidence for fracture flow also is apparent in the widespread occurrence of perched water with chemical and isotopic signatures that indicate a fracture-flow origin for at least some of this water. In the North Ramp area, perched water has been detected at the base of the Topopah Spring Tuff or in the top of the underlying non welded to partially welded tuffs of the Calico Hills Formation in every dry-drilled borehole of sufficient depth to penetrate the Topopah Spring Tuff-Calico Hills Formation contact. The concentrations of the major ions of the perched water are similar to that of TSw pore water at borehole UZ

Pretest thermal analysis of the Tuff Water Migration/In-Situ Heater Experiment

International Nuclear Information System (INIS)

Bulmer, B.M.

1980-02-01

This report describes the pretest thermal analysis for the Tuff Water Migration/In-Situ Heater Experiment to be conducted in welded tuff in G-tunnel, Nevada Test Site. The parametric thermal modeling considers variable boiling temperature, tuff thermal conductivity, tuff emissivity, and heater operating power. For nominal tuff properties, some near field boiling is predicted for realistic operating power. However, the extent of boiling will be strongly determined by the ambient (100% water saturated) rock thermal conductivity. In addition, the thermal response of the heater and of the tuff within the dry-out zone (i.e., bounded by boiling isotherm) is dependent on the temperature variation of rock conductivity as well as the extent of induced boiling

Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

OpenAIRE

Escobedo-Lozano, Amada Y.; Estrada, Norma; Ascencio, Felipe; Contreras, Gerardo; Alonso-Rodriguez, Rosalba

2012-01-01

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopic...

Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

International Nuclear Information System (INIS)

Heiken, G.H.; Bevier, M.L.

1979-01-01

The J-13 drill hole, located in Jackass Flats, Nevada Test Site, has penetrated 125 m of alluvium and 932 m of tuff. Most of the tuff deposits consist of welded tuffs; glass phases in the tuffs have been replaced by authigenic minerals, mainly K-feldspar, silica, and zeolites. The zonation of authigenic minerals, with depth, indictes that alteration of glass phases and filling of vugs occurred during welding and compaction of tuff units soon after deposition and by interaction with groundwater. Zonation of authigenic minerals in tuff deposits at Jackass Flats is similar to mineral zonation in tuffs elsewhere at the Nevada Test Site and in tuff deposits of west Texas. All appear to have been developed by leaching of glass phases and deposition of authigenic minerals in open hydrologic systems. 10 figures, 38 tables

First phase of small diameter heater experiments in tuff

International Nuclear Information System (INIS)

Zimmerman, R.M.

1983-01-01

As part of the Nevada Nuclear Waste Storage Investigations (NNWSI) project, we have undertaken small diameter heater experiments in the G-Tunnel Underground Facility on the Nevada Test Site (NTS). These experiments are to evaluate the thermal and hydrothermal behavior which might be encountered if heat producing nuclear waste were disposed of in welded and nonwelded tuffs. The two Phase I experiments discussed have focused on vertical borehole emplacements. In each experiment, temperatures were measured along the surface of the 10.2-cm-dia heater and the 12.7-cm-dia boreholes. For each experiment, measurements were compared with computer model representations. Maximum temperatures reached were: 196 0 C for the welded tuff after 21 days of operations at 800W and 173 0 C for the nonwelded tuff after 35 days of operations at 500W. Computed results indicate that the same heat transfer model (includes conduction and radiation only) can describe the behavior of both tuffs using empirical techniques to describe pore water vaporization. Hydrothermal measurements revealed heat-indiced water migration. Results indicated that small amounts of liquid water migrated into the welded tuff borehole early in the heating period. Once the rock-wall temperatures exceeded 94 0 C, in both tuffs, there was mass transport of water vapor as evidence indicated condensation cooler regions. Borehole pressures remained essentially ambient during the thermal periods

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Tyburski, J.R.

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application

Slip rate of the Calico fault: Implications for geologic versus geodetic rate discrepancy in the Eastern California Shear Zone

Science.gov (United States)

Oskin, Michael; Perg, Lesley; Blumentritt, Dylan; Mukhopadhyay, Sujoy; Iriondo, Alexander

2007-03-01

Long-term (105 years) fault slip rates test the scale of discrepancy between infrequent paleoseismicity and relatively rapid geodetic rates of dextral shear in the Eastern California Shear Zone (ECSZ). The Calico fault is one of a family of dextral faults that traverse the Mojave Desert portion of the ECSZ. Its slip rate is determined from matching and dating incised Pleistocene alluvial fan deposits and surfaces displaced by fault slip. A high-resolution topographic base acquired via airborne laser swath mapping aids in identification and mapping of deformed geomorphic features. The oldest geomorphically preserved alluvial fan, unit B, is displaced 900 ± 200 m from its source at Sheep Springs Wash in the northern Rodman Mountains. This fan deposit contains the first preserved occurrence of basalt clasts derived from the Pipkin lava field and overlies Quaternary conglomerate deposits lacking these clasts. The 40Ar/39Ar dating of two flows from this field yields consistent ages of 770 ± 40 ka and 735 ± 9 ka. An age of 650 ± 100 ka is assigned to this fan deposit based on these ages and on the oldest cosmogenic 3He exposure date of 653 ± 20 ka on a basalt boulder from the surface of unit B. This assigned age and offset together yield a mid-Pleistocene to present average slip rate of 1.4 ± 0.4 mm/yr. A younger fan surface, unit K, records 100 ± 10 m of dextral displacement and preserves original depositional morphology of its surface. Granitic boulders and pavement samples from this surface yield an average age of 56.4 ± 7.7 ka after taking into account minimal cosmogenic inheritance of granitic clasts. The displaced and dated K fans yield a slip rate of 1.8 ± 0.3 mm/yr. Distributed deformation of the region surrounding the fault trace, if active, could increase the overall displacement rate to 2.1 ± 0.5 mm/yr. Acceleration of slip rate from an average of 1.4 mm/yr prior to ˜50 ka to 1.8 mm/yr since ˜50 ka is possible, though a single time-averaged slip

The effect of saturation of the mechanical properties of tuff at Yucca Mountain

International Nuclear Information System (INIS)

Karakouzian, M.; Hudyma, N.

1996-01-01

This study investigates the effect of saturation on the mechanical properties, namely compressive strength and Young's Modulus, of Tiva Canyon welded tuff and Topopah Spring welded tuff from the Nevada Test Site. Unconfined compression tests on air dried and saturated specimens show that saturation lowers both the average compressive strength and the average Young's Modulus of Topopah Spring and Tiva Canyon tuff specimens. Saturation increases the variability of the mechanical properties of Topopah Spring tuff and the variability of the compressive strength of Tiva Canyon tuff

Field trip report: Observations made at Yucca Mountain, Nye County, Nevada. Special report No. 2

International Nuclear Information System (INIS)

Hill, C.A.

1993-03-01

A field trip was made to the Yucca Mountain area on December 5-9, 1992 by Jerry Frazier, Don Livingston, Christine Schluter, Russell Harmon, and Carol Hill. Forty-three separate stops were made and 275 lbs. of rocks were collected during the five days of the field trip. Key localities visited were the Bare Mountains, Yucca Mountain, Calico Hills, Busted Butte, Harper Valley, Red Cliff Gulch, Wahmonie Hills, Crater Flat, and Lathrop Wells Cone. This report only describes field observations made by Carol Hill. Drawings are used rather than photographs because cameras were not permitted on the Nevada Test Site during this trip

THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS

Energy Technology Data Exchange (ETDEWEB)

R. JONES

2004-10-22

This model report addresses activities described in ''Technical Work Plan for: Near-Field Environment and Transport Thermal Properties and Analysis Reports Integration'' (BSC 2004 [DIRS 171708]). The model develops values for thermal conductivity, and its uncertainty, for the nonrepository layers of Yucca Mountain; in addition, the model provides estimates for matrix porosity and dry bulk density for the nonrepository layers. The studied lithostratigraphic units, as identified in the ''Geologic Framework Model'' (GFM 2000) (BSC 2004 [DIRS 170029]), are the Timber Mountain Group, the Tiva Canyon Tuff, the Yucca Mountain Tuff, the Pah Canyon Tuff, the Topopah Spring Tuff (excluding the repository layers), the Calico Hills Formation, the Prow Pass Tuff, the Bullfrog Tuff, and the Tram Tuff. The deepest model units of the GFM (Tund and Paleozoic) are excluded from this study because no data suitable for model input are available. The parameter estimates developed in this report are used as input to various models and calculations that simulate heat transport through the rock mass. Specifically, analysis model reports that use product output from this report are: (1) Drift-scale coupled processes (DST and TH seepage) models; (2) Drift degradation analysis; (3) Multiscale thermohydrologic model; and (4) Ventilation model and analysis report. In keeping with the methodology of the thermal conductivity model for the repository layers in ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]), the Hsu et al. (1995 [DIRS 158073]) three-dimensional (3-D) cubic model (referred to herein as ''the Hsu model'') was used to represent the matrix thermal conductivity as a function of the four parameters (matrix porosity, thermal conductivity of the saturating fluid, thermal conductivity of the solid, and geometric connectivity of the solid). The Hsu model requires input data

Reactivity of a tuff-bearing concrete: CL-40 CON-14

International Nuclear Information System (INIS)

Scheetz, B.E.; Roy, D.M.

1989-04-01

Samples of a tuff-bearing concrete have been altered in J-13 groundwater and in the vapor phase over deionized water at 200/degree/C. Crushed and intact discs of the concrete have been studied. The glassy tuff component of the tuff was more extensively reacted than the welded devitrified tuff. The original concrete was formulated to be expansive on curing through the formation of the calcium alumino-sulfate hydrate phase, ettringite. An x-ray diffraction examination of the altered crushed samples shows that the ettringite is no longer present. The original, poorly crystalline calcium-silicate-hydrate has recrystallized to tobermorite. In the rocking autoclave experiments with crushed material, which are the experiments expected to have the fastest reaction rates, the tobermorite has been replaced by a mineral of the gyrolite-truscottite group at the longer reaction times. The disc experiments in J-13 groundwater are characterized by prominent dissolution of the tuff aggregate. Alteration in the vapor phase experiments is primarily in the form of overgrowths on the discs. 10 refs., 27 figs., 12 tabs

Interpretation of gravity data in a complex volcano-tectonic setting, southwestern Nevada

International Nuclear Information System (INIS)

Snyder, D.B.; Carr, W.J.

1984-01-01

This regional gravity study was conducted during the past few years at Yucca Mountain, southern Nye County, Nevada, as part of a program to locate a suitable repository for high-level nuclear waste. About 100 surface rock samples, three borehole gamma-gamma logs, and one borehole gravity study provide excellent density control. A nearly linear increase in density of 0.26 g/cm 3 per kilometer of depth is indicated in the thick tuff sequences that underlie the mountain. Isostatic and 2.0-g/cm 3 Bouguer corrections were applied to the observed gravity values to remove regional gradients and topographic effects, respectively. The Bare Mountain gravity high is connected with a greater gravity high over the Funeral Mountains, to the southwest; together, these highs result from a continuous block of dense, metamorphosed Precambrian and Paleozoic rocks that stretches across much of the Walker Lane from the east edge of Death Valley to Bare Mountain. The Calico Hills gravity high appears more likely to originate from a northeast trending buried ridge of Paleozoic rocks that extends southwestward beneath Busted Butte, 5 km southeast of the proposed repository, where two- and three-dimensional modeling indicates that the pre-Cenozoic rocks lie less than 1000 m beneath the surface. Tuff, at least 4000 m thick, fills a large steep-sided depression in the pretuff rocks beneath Yucca Mountain and Crater Flat. The gravity low and the thick tuff section lie within a large collapse area that includes the Crater Flat-Timber Mountain-Silent Canyon caldera complexes. Southward extension of the broad gravity low associated with Crater Flat into the Amargosa Desert is evidence for sector graben-type collapse sediments related to the information of the Timber Mountain caldera and superimposed on the other volcanic and extensional structures within Crater Flat. 48 references, 6 figures, 2 tables

Measuring and modeling water imbibition into tuff

International Nuclear Information System (INIS)

Peters, R.R.; Klavetter, E.A.; George, J.T.; Gauthier, J.H.

1986-01-01

Yucca Mountain (Nevada) is being investigated as a potential site for a high-level-radioactive-waste repository. The site combines a partially saturated hydrologic system and a stratigraphy of fractured, welded and nonwelded tuffs. The long time scale for site hydrologic phenomena makes their direct measurement prohibitive. Also, modeling is difficult because the tuffs exhibit widely varying, and often highly nonlinear hydrologic properties. To increase a basic understanding of both the hydrologic properties of tuffs and the modeling of flow in partially saturated regimes, the following tasks were performed, and the results are reported: (1) Laboratory Experiment: Water imbibition into a cylinder of tuff (taken from Yucca Mountain drill core) was measured by immersing one end of a dry sample in water and noting its weight at various times. The flow of water was approximately one-dimensional, filling the sample from bottom to top. (2) Computer Simulation: The experiment was modeled using TOSPAC (a one-dimensional, finite-difference computer program for simulating water flow in partially saturated, fractured, layered media) with data currently considered for use in site-scale modeling of a repository in Yucca Mountain. The measurements and the results of the modeling are compared. Conclusions are drawn with respect to the accuracy of modeling transient flow in a partially saturated, porous medium using a one-dimensional model and currently available hydrologic-property data

Cornstarch as a dietary supplement in conditioning broodstock and spat at a nursery of the Pacific calico scallop, Argopecten ventricosus

OpenAIRE

Mazón-Suástegui, José Manuel; Lodeiros, Cesar; Avilés-Quevedo, Araceli; Rodríguez-Jaramillo, Carmen; Ortiz-Cornejo, Nadia; Abasolo-Pacheco, Fernando

2017-01-01

ABSTRACT Microalgae diets supplemented with cornstarch at a rate of 0.15% of live weight to the conditioning of broodstock and spat growth of Pacific calico scallop Argopecten ventricosus were tested. To determine reproductive condition at the beginning and end of the experiment, the gonads of adults were analyzed by stereological methods. For juveniles, the weekly percent increase of spat was estimated from spat biomass volume. The microalgae diet of Tisochrysis lutea and Chaetoceros calcitr...

Laboratory investigation of constitutive property up-scaling in volcanic tuffs

International Nuclear Information System (INIS)

Tidwell, V.C.

1996-08-01

One of the critical issues facing the Yucca Mountain site characterization and performance assessment programs is the manner in which property up-scaling is addressed. Property up-scaling becomes an issue whenever heterogeneous media properties are measured at one scale but applied at another. A research program has been established to challenge current understanding of property up-scaling with the aim of developing and testing improved models that describe up-scaling behavior in a quantitative manner. Up-scaling of constitutive rock properties is investigated through physical experimentation involving the collection of suites of gas-permeability data measured over a range of discrete scales. To date, up-scaling studies have been performed on a series of tuff and sandstone (used as experimental controls) blocks. Samples include a welded, anisotropic tuff (Tiva Canyon Member of the Paintbrush Tuff, upper cliff microstratigraphic unit), and a moderately welded tuff (Tiva Canyon Member of the Paintbrush Tuff, Caprock microstratigraphic unit). A massive fluvial sandstone (Berea Sandstone) was also investigated as a means of evaluating the experimental program and to provide a point of comparison for the tuff data. Because unsaturated flow is of prime interest to the Yucca Mountain Program, scoping studies aimed at investigating the up-scaling of hydraulic properties under various saturated conditions were performed to compliment these studies of intrinsic permeability. These studies focused on matrix sorptivity, a constitutive property quantifying the capillarity of a porous medium. 113 refs

Anisotropy of the Topopah Spring Member Tuff

International Nuclear Information System (INIS)

Martin, R.J. III; Boyd, P.J.; Haupt, R.W.; Price, R.H.

1992-07-01

Mechanical properties of the tuffaceous rocks within Yucca Mountain are needed for near and far-field modeling of the potential nuclear waste repository. If the mechanical properties are significantly anisotropic (i.e., direction-dependent), a more complex model is required. Relevant data from tuffs tested in earlier studies indicate that elastic and strength properties are anisotropic. This scoping study confirms the elastic anisotropy and concludes some tuffs are transversely isotropic. An approach for sampling and testing the rock to determine the magnitude of the anisotropy is proposed

Transport of neptunium through Yucca Mountain tuffs

International Nuclear Information System (INIS)

Triay, I.R.; Robinson, B.A.; Mitchell, A.J.; Overly, C.M.; Lopez, R.M.

1993-01-01

Neptunium has a high solubility in groundwaters from Yucca Mountain [1]. Uranium in nuclear reactors produces 237 Np which has a half-life of 2.1 4 x 10 6 years. Consequently, the transport of 237 Np through tuffs is of major importance in assessing the performance of a high-level nuclear waste repository at Yucca Mountain. The objective of this work is to determine the amount of Np retardation that is provided by the minerals in Yucca Mountain tuffs as a function of groundwater chemistry

Mechanical tunnel excavation in welded tuff

International Nuclear Information System (INIS)

Sperry, P.E.

1991-01-01

The Technical Review Board for the US high-level radioactive waste facility at Yucca Mountain has recommended maximum use of open-quotes the most modern mechanical excavation techniques...in order to reduce disturbance to the rock walls and to achieve greater economy of time and cost.close quotes Tunnels for the waste repository at Yucca Mountain can be economically constructed with mechanical excavation equipment. This paper presents the results of mechanical excavation of a tunnel in welded tuff, similar to the tuffs of Yucca Mountain. These results are projected to excavation of emplacement drifts in Yucca Mountain using a current state-of-the-art tunnel boring machine (TBM)

METHODS FOR PORE WATER EXTRACTION FROM UNSATURATED ZONE TUFF, YUCCA MOUNTAIN, NEVADA

International Nuclear Information System (INIS)

K.M. SCOFIELD

2006-01-01

Assessing the performance of the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, requires an understanding of the chemistry of the water that moves through the host rock. The uniaxial compression method used to extract pore water from samples of tuffaceous borehole core was successful only for nonwelded tuff. An ultracentrifugation method was adopted to extract pore water from samples of the densely welded tuff of the proposed repository horizon. Tests were performed using both methods to determine the efficiency of pore water extraction and the potential effects on pore water chemistry. Test results indicate that uniaxial compression is most efficient for extracting pore water from nonwelded tuff, while ultracentrifugation is more successful in extracting pore water from densely welded tuff. Pore water splits taken from a single nonwelded tuff core during uniaxial compression tests have shown changes in pore water chemistry with increasing pressure for calcium, chloride, sulfate, and nitrate, while the chemistry of pore water splits from welded and nonwelded tuffs using ultracentrifugation indicates that there is no significant fractionation of solutes

Measuring geomechanical properties of Topopah Spring Tuff at the 1-meter scale

International Nuclear Information System (INIS)

Blair, S.C.; Berge, P.A.

1994-11-01

The Yucca Mountain Site Characterization Project is studying physical and chemical properties of Topopah Spring tuff and coupled thermal, mechanical, hydrological, and geochemical processes expected in the near-field environment of the potential waste repository at Yucca Mountain, Nevada. Investigating the suitability of Topopah Spring tuff as a host rock for radioactive waste disposal includes measuring mechanical properties. Since heterogeneities vary with scale, from vugs and cracks at the hand-sample scale to fractures and vertical variations in degree of welding at the outcrop scale, mechanical properties of the tuff depend on scale. The Lawrence Livermore National Laboratory has planned a Large Block Test (LBT) to investigate rock mass properties and coupled processes at elevated temperatures in Topopah Spring tuff at the scale of a few meters. This paper describes planned laboratory experiments in support of the LBT, to measure elastic properties and mechanical behavior of Topopah Spring tuff at the scale of a few cm to 1 m. The laboratory experiments will include measurement of stress-strain behavior, acoustic emissions during heating, and elastic wave velocities in small blocks of tuff

Eocene age of the Baranowski Glacier Group at Red Hill, King George Island, West Antarctica

Directory of Open Access Journals (Sweden)

Mozer Anna

2015-12-01

Full Text Available Radiometric and geochemical studies were carried out at Red Hill in the southern part of King George Island (South Shetland Islands, northern Antarctic Peninsula on the Bransfield Strait coast. The rock succession at Red Hill has been determined to represent the Baranowski Glacier Group that was previously assigned a Late Cretaceous age. Two formations were distinguished within this succession: the lower Llano Point Formation and the upper Zamek Formation. These formations have stratotypes defined further to the north on the western coast of Admiralty Bay. On Red Hill the Llano Point Formation consists of terrestrial lavas and pyroclastic breccia; the Zamek Formation consist predominantly of fine to coarse tuff, pyroclastic breccia, lavas, tuffaceous mud-, silt-, and sandstone, locally conglomeratic. The lower part of the Zamek Formation contains plant detritus (Nothofagus, dicotyledonous, thermophilous ferns and numerous coal seams (vitrinitic composition that confirm the abundance of vegetation on stratovolcanic slopes and surrounding lowlands at that time. Selected basic to intermediate igneous rocks from the succession have been analysed for the whole-rock K-Ar age determination. The obtained results indicate that the Red Hill succession was formed in two stages: (1 from about 51–50 Ma; and (2 46–42 Ma, i.e. during the Early to Middle Eocene. This, in combination with other data obtained from other Baranowski Glacier Group exposures on western coast of Admiralty Bay, confirms the recently defined position of the volcano-clastic succession in the stratigraphic scheme of King George Island. The new stratigraphic position and lithofacies development of the Red Hill succession strongly suggest its correlation with other Eocene formations containing fossil plants and coal seams that commonly occur on King George Island.

Stratigraphy of the Bandelier Tuff in the Pajarito Plateau. Applications to waste management

International Nuclear Information System (INIS)

Crowe, B.M.; Linn, G.W.; Heiken, G.; Bevier, M.L.

1978-04-01

The Bandelier Tuff within the Pajarito Plateau consists of a lower sequence of air-fall and ash-flow deposits (Otowi Member) disconformably overlain by an upper sequence of air-fall and ash-flow deposits (Tshirege Member). The ash-flow sequence of the Tshirege Member consists of three cooling units throughout much of the Pajarito Plateau. The lower cooling unit is formed by three to as many as six pyroclastic flow units; the middle and upper cooling units each consist of at least three pyroclastic flow units. The contact between the lower and middle cooling unit coincides with a pyroclastic flow unit contact. This horizon is a prominent stratigraphic marker within distal sections of the Tshirege Member. Major and trace element analyses of unaltered and altered samples of the Bandelier Tuff were determined by neutron activation and delayed neutron activation and delayed neutron activation techniques. Petrographic, granulometric and morphologic characteristics of the Bandelier Tuff were determined to provide background information on the suitability of the Tuff as a medium for radioactive waste disposal. The hydrologic characteristics of the Bandelier Tuff are controlled primarily by secondary features of the Tuff (cooling zones). These features vary with emplacement temperature and transport distance of the Tuff. Primary depositional features provide second order control on transport pathways in distal sections of the Tuff

Parametric analysis of a TOUGH2 model for the unsaturated zone at Yucca Mountain

Energy Technology Data Exchange (ETDEWEB)

Xiang, Y.; Mishra, S.; Dunlap, B. [CRWMS M& O/INTERA, Inc., Las Vegas, NV (United States)

1995-03-01

Yucca Mountain in Nevada is currently being investigated for suitability as a potential site for the disposal of high-level radioactive waste and spent nuclear fuel. As the most important natural barrier against radionuclide migration to the accessible environment, the unsaturated zone at Yucca mountain is a key constituent in assessing the ambient geohydrology. A three-dimensional site-scale TOUGH2 model of the unsaturated zone is currently under development by Lawrence Berkeley Laboratory (LBL) and the United States Geological Survey (USGS) consists of six hydrogeologic units - TCw (Tiva Canyon welded), PTn (Paintbrush nonwelded), TSw (Topopah Spring welded), TSv (Topopah Spring welded-vitrophyre), CHnz (Calico Hills nonwelded-vitric), and CHnz (Calico Hills nonwelded-zeolitic), which are further subdivided into seventeen layers to represent additional lithologic detail. Based on the work of Klavetter and Peters, the fractured units TCw and TSw are treated as equivalent continua with specified threshold saturation for triggering fracture flow.

In-situ tuff water migration/heater experiment: experimental plan

International Nuclear Information System (INIS)

Johnstone, J.K.

1980-08-01

Tuffs on the Nevada Test Site (NTS) are currently under investigation as a potential isolation medium for heat-producing nuclear wastes. The National Academy of Sciences has concurred in our identification of the potentially large water content (less than or equal to 40 vol %) of tuffs as one of the important issues affecting their suitability for a repository. This Experimental Plan describes an in-situ experiment intended as an initial assessment of water generation/migration in response to a thermal input. The experiment will be conducted in the Grouse Canyon Welded Tuff in Tunnel U12g (G-Tunnel) located in the north-central region of the NTS. While the Grouse Canyon Welded Tuff is not a potential repository medium, it has physical, thermal, and mechanical properties very similar to those tuffs currently under consideration and is accessible at depth (400 m below the surface) in an existing facility. Other goals of the experiment are to support computer-code and instrumentation development, and to measure in-situ thermal properties. The experimental array consists of a central electrical heater, 1.2 m long x 10.2 cm diameter, surrounded by three holes for measuring water-migration behavior, two holes for measuring temperature profiles, one hole for measuring thermally induced stress in the rock, and one hole perpendicular to the heater to measure displacement with a laser. This Experimental Plan describes the experimental objectives, the technical issues, the site, the experimental array, thermal and thermomechanical modeling results, the instrumentation, the data-acquisition system, posttest characterization, and the organizational details

Fission-track dating of pumice from the KBS Tuff, East Rudolf, Kenya

Science.gov (United States)

Hurford, A.J.; Gleadow, A.J.W.; Naeser, C.W.

1976-01-01

Fission-track dating of zircon separated from two pumice samples from the KBS Tuff in the Koobi Fora Formation, in Area 131, East Rudolf, Kenya, gives an age of 2.44??0.08 Myr for the eruption of the pumice. This result is compatible with the previously published K-Ar and 40Ar/ 39Ar age spectrum estimate of 2.61??0.26 Myr for the KBS Tuff in Area 105, but differs from the more recently published K-Ar date of 1.82??0.04 Myr for the KBS Tuff in Area 131. This study does not support the suggestion that pumice cobbles of different ages occur in the KBS Tuff. ?? 1976 Nature Publishing Group.

Feldspar dissolution rates in the Topopah Spring Tuff, Yucca Mountain, Nevada

Science.gov (United States)

Bryan, C.R.; Helean, K.B.; Marshall, B.D.; Brady, P.V.

2009-01-01

Two different field-based methods are used here to calculate feldspar dissolution rates in the Topopah Spring Tuff, the host rock for the proposed nuclear waste repository at Yucca Mountain, Nevada. The center of the tuff is a high silica rhyolite, consisting largely of alkali feldspar (???60 wt%) and quartz polymorphs (???35 wt%) that formed by devitrification of rhyolitic glass as the tuff cooled. First, the abundance of secondary aluminosilicates is used to estimate the cumulative amount of feldspar dissolution over the history of the tuff, and an ambient dissolution rate is calculated by using the estimated thermal history. Second, the feldspar dissolution rate is calculated by using measured Sr isotope compositions for the pore water and rock. Pore waters display systematic changes in Sr isotopic composition with depth that are caused by feldspar dissolution. The range in dissolution rates determined from secondary mineral abundances varies from 10-16 to 10-17 mol s-1 kg tuff-1 with the largest uncertainty being the effect of the early thermal history of the tuff. Dissolution rates based on pore water Sr isotopic data were calculated by treating percolation flux parametrically, and vary from 10-15 to 10-16 mol s-1 kg tuff-1 for percolation fluxes of 15 mm a-1 and 1 mm a-1, respectively. Reconciling the rates from the two methods requires that percolation fluxes at the sampled locations be a few mm a-1 or less. The calculated feldspar dissolution rates are low relative to other measured field-based feldspar dissolution rates, possibly due to the age (12.8 Ma) of the unsaturated system at Yucca Mountain; because oxidizing and organic-poor conditions limit biological activity; and/or because elevated silica concentrations in the pore waters (???50 mg L-1) may inhibit feldspar dissolution. ?? 2009 Elsevier Ltd. All rights reserved.

Felsic tuff from Rutland Island – A pyroclastic flow deposit in ...

Indian Academy of Sciences (India)

: • white massive tuff with ill-defined bedding contacts (facies-A) and. • dominantly green tuff exhibiting well-developed turbidite sequence with up-section change from a massive unit to plane laminated units to ripple drift lamination (facies-B).

Measuring and Modeling Flow in Welded Fractured Tuffs

International Nuclear Information System (INIS)

R. Salve; C. Doughty; J.S. Wang

2001-01-01

We have carried out a series of in situ liquid-release experiments in conjunction with a numerical modeling study to examine the effect of the rock matrix on liquid flow and transport occurring primarily through the fracture network. Field experiments were conducted in the highly fractured Topopah Spring welded tuff at a site accessed from the Exploratory Studies Facility (ESFS), an underground laboratory in the unsaturated zone at Yucca Mountain, Nevada. During the experiment, wetting-front movement, flow-field evolution, and drainage of fracture flow paths were evaluated. Modeling was used to aid in experimental design, predict experimental results, and study the physical processes accompanying liquid flow through unsaturated fractured welded tuff. Field experiments and modeling suggest that it may not be sufficient to conceptualize the fractured tuff as consisting of a single network of high-permeability fractures embedded in a low-permeability matrix. The need to include a secondary fracture network is demonstrated by comparison to the liquid flow observed in the field

Issues related to field testing in tuff

International Nuclear Information System (INIS)

Zimmerman, R.M.

1982-01-01

This paper has brought out the unique properties of tuffs and related them to needs associated with their use as a host rock for a high level nuclear waste repository. Major issues of temperature, pore water, joints, and depositional patterns have been identified and related responses and impacts outlined in Table 1. Planned experiments have been outlined and their relationships to the rock mechanics issues summarized in Table 2. The conclusions from this paper are: (1) tuff is a complex rock and basic phenomenological understanding is incomplete; and (2) available field test facilities will be used for a series of experiments designed to improve phenomenological understanding and support repository design efforts

Magnetic properties and emplacement of the Bishop tuff, California

Science.gov (United States)

Palmer, H.C.; MacDonald, W.D.; Gromme, C.S.; Ellwood, B.B.

1996-01-01

Anisotropy of magnetic susceptibility (AMS) and characteristic remanence were measured for 45 sites in the 0.76 Ma Bishop tuff, eastern California. Thirty-three sites were sampled in three stratigraphic sections, two in Owens gorge south of Long Valley caldera, and the third in the Adobe lobe north of Long Valley. The remaining 12 sites are widely distributed, but of limited stratigraphic extent. Weakly indurated, highly porous to dense, welded ash-flow tuffs were sampled. Saturation magnetization vs temperature experiments indicate two principal iron oxide phases: low Ti magnetites with 525-570 ??C Curie temperatures, and maghemite with 610??-640??C Curie temperatures. AF demagnetization spectra of isothermal remanent magnetizations are indicative of magnetite/maghemite predominantly in the multidomain to pseudo-single domain size ranges. Remeasurement of AMS after application of saturating direct fields indicates that randomly oriented single-domain grains are also present. The degree of anisotropy is only a few percent, typical of tuffs. The AMS ellipsoids are oblate with Kmin axes normal to subhorizontal foliation and Kmax axes regionally aligned with published source vents. For 12 of 16 locality means, Kmax axes plunge sourceward, confirming previous observations regarding flow sense. Topographic control on flow emplacement is indicated by the distribution of tuff deposits and by flow directions inferred from Kmax axes. Deposition east of the Benton range occurred by flow around the south end of the range and through two gaps (Benton notch and Chidago gap). Flow down Mammoth pass of the Sierra Nevada is also evident. At least some of the Adobe lobe in the northeast flowed around the west end of Glass mountain. Eastward flow directions in the upper Owens gorge and southeast directions in the lower Owens gorge are parallel to the present canyon, suggesting that the present drainage has been established along the pre-Bishop paleodrainage. Characteristic remanence

Laboratory determined suction potential of Topopah Spring tuff at high temperatures

International Nuclear Information System (INIS)

Daily, W.; Lin, Wunan.

1991-01-01

The purpose of this work is to experimentally determine the capillary suction potential of Topopah Spring tuff from Yucca Mountain, Nye County, Nevada. This data can be used to help characterize the unsaturated hydraulic properties of the densely welded tuff at this site. 7 refs., 4 figs., 1 tab

Mineralogy, geochemistry and petrogenesis of volcanic tuffs from Ataraws, Jordan

International Nuclear Information System (INIS)

Al-Fugha, H.

1997-01-01

Magistracy are common in tuff and paralytic's materials of Pleistocene age in western Jordan. The dominant phases are olivine, augite, plagioclase, magnetite and ilmenite. Chemical analysis of the whole rocks samples indicate alkali olivine magma origin. Low concentration of Li and Rb in Tuff samples are used as an argument against the contamination of the basaltic magma during its journey to the surface. The Mg O and mg- values (Mg/Mg+Fe 2+ ) in samples from volcano exhibit different degrees of fractionation, which are indicated by the varying concentrations of incompatible trace elements (Ba, Rb, Sr). The thermometric evacuation of tuff formation by using pyroxenes thermometers revealed a temperature range between 1022-1083 deg. and pressure of 5-10 K bars. The low Mg-ratio (Mg/Mg+Fe 2+ ) is due to fractional crystallization of olivine and pyroxene in tuff samples. The variation of incompatible elements imply derivation from a peridotite source in the upper mantle with low degree of melting (<20%).The volcanic activity took place in phases corresponding to rifting sinistral displacement along the Jordan Rift. (author). 11 refs., 6 tabs, 6 figs

Borehole stability in densely welded tuffs

International Nuclear Information System (INIS)

Fuenkajorn, K.; Daemen, J.J.K.

1992-07-01

The stability of boreholes, or more generally of underground openings (i.e. including shafts, ramps, drifts, tunnels, etc.) at locations where seals or plugs are to be placed is an important consideration in seal design for a repository (Juhlin and Sandstedt, 1989). Borehole instability or borehole breakouts induced by stress redistribution could negate the effectiveness of seals or plugs. Breakout fractures along the wall of repository excavations or exploratory holes could provide a preferential flowpath for groundwater or gaseous radionuclides to bypass the plugs. After plug installation, swelling pressures exerted by a plug could induce radial cracks or could open or widen preexisting cracks in the rock at the bottom of the breakouts where the tangential compressive stresses have been released by the breakout process. The purpose of the work reported here is to determine experimentally the stability of a circular hole in a welded tuff sample subjected to various external boundary loads. Triaxial and biaxial borehole stability tests have been performed on densely welded Apache Leap tuff samples and Topopah Spring tuff samples. The nominal diameter of the test hole is 13.3 or 14.4 mm for triaxial testing, and 25.4 mm for biaxial testing. The borehole axis is parallel to one of the principal stress axes. The boreholes are drilled through the samples prior to applying external boundary loads. The boundary loads are progressively increased until breakouts occur or until the maximum load capacity of the loading system has been reached. 74 refs

Geologic character of tuffs in the unsaturated zone at Yucca Mountain, southern Nevada

International Nuclear Information System (INIS)

Scott, R.B.; Spengler, R.W.; Diehl, S.; Lappin, A.R.; Chornack, M.P.

1982-01-01

At Yucca Mountain, a potential site for a high-level nuclear waste repository on the Nevada Test Site in southern Nevada, evaluation of the geologic setting and rock physical properties, along with previous regional hydrologic studies, has provided background that can be used for construction of a preliminary conceptual hydrologic model of the unsaturated zone. The 500-m-thick unsaturated portion of Yucca Mountain consists of alternating layers of two contrasting types of tuff. One type consists of highly fractured, densely welded, relatively nonporous but highly transmissive ash-flow tuffs. The other type consists of relatively unfractured, nonwelded, highly porous but relatively nontransmissive, argillic and zeolitic bedded tuffs and ash-flow tuffs. The contrast between these two sets of distinctive physical properties results in a stratified sequence best described as ''physical-property stratigraphy'' as opposed to traditional petrologic stratigraphy of volcanic rocks. The vast majority of recharge through the unsaturated zone is assumed to be vertical; the dominant migration may occur in fractures of densely welded tuffs and in the matrix of nonwelded tuff, but the mode of fluid flow in these unsaturated systems is undetermined. Limited lateral flow of recharge may occur at horizons where local perched water tables may exist above relatively nontransmissive zeolitized nonwelded tuffs. The pervasive north-northwest-striking fractures may control the direction of lateral flow of recharge, if any, in the unsaturated zone, and certainly that direction coincides closely with the observed southeasterly flow direction in the saturated zone under Yucca Mountain. Empirical evaluation of this conceptual hydrologic model has begun. 41 refs., 18 figs., 2 tabs

Geologic character of tuffs in the unsaturated zone at Yucca Mountain, southern Nevada

Energy Technology Data Exchange (ETDEWEB)

Scott, R.B.; Spengler, R.W.; Diehl, S.; Lappin, A.R.; Chornack, M.P.

1982-12-31

At Yucca Mountain, a potential site for a high-level nuclear waste repository on the Nevada Test Site in southern Nevada, evaluation of the geologic setting and rock physical properties, along with previous regional hydrologic studies, has provided background that can be used for construction of a preliminary conceptual hydrologic model of the unsaturated zone. The 500-m-thick unsaturated portion of Yucca Mountain consists of alternating layers of two contrasting types of tuff. One type consists of highly fractured, densely welded, relatively nonporous but highly transmissive ash-flow tuffs. The other type consists of relatively unfractured, nonwelded, highly porous but relatively nontransmissive, argillic and zeolitic bedded tuffs and ash-flow tuffs. The contrast between these two sets of distinctive physical properties results in a stratified sequence best described as "physical-property stratigraphy" as opposed to traditional petrologic stratigraphy of volcanic rocks. The vast majority of recharge through the unsaturated zone is assumed to be vertical; the dominant migration may occur in fractures of densely welded tuffs and in the matrix of nonwelded tuff, but the mode of fluid flow in these unsaturated systems is undetermined. Limited lateral flow of recharge may occur at horizons where local perched water tables may exist above relatively nontransmissive zeolitized nonwelded tuffs. The pervasive north-northwest-striking fractures may control the direction of lateral flow of recharge, if any, in the unsaturated zone, and certainly that direction coincides closely with the observed southeasterly flow direction in the saturated zone under Yucca Mountain. Empirical evaluation of this conceptual hydrologic model has begun. 41 refs., 18 figs., 2 tabs.

G-Tunnel welded tuff mining experiment data summary

International Nuclear Information System (INIS)

Zimmerman, R.M.; Bellman, R.A. Jr.; Mann, K.L.; Zerga, D.P.; Fowler, M.

1990-03-01

Designers and analysts of radioactive waste repositories must be ably to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a mine-by in welded tuff so that predictive-type information could be obtained regarding the response of the rock to a drill and blast excavation process, where smooth blasting techniques were used. Included in the study were evaluations of and recommendations for various measurement systems that might be used in future mine by efforts. This report summarizes all of the data obtained in the welded tuff mining experiment. 6 refs., 29 figs., 12 tabs

Chemistry and mineralogy of some Plio-Pleistocene tuffs from the Shungura Formation, southwest Ethiopia

Science.gov (United States)

Martz, A. M.; Brown, F. H.

1981-09-01

The Shungura Formation of southwestern Ethiopia has yielded many tens of thousands of vertebrate fossils including hominids and microvertebrates, and in addition has also yielded fossil wood, pollen, and invertebrates. Widespread tuffs have made subdivision and detailed mapping of the formation possible, have provided material for potassium-argon dating, and have allowed direct lithostratigraphic correlation with the Koobi Fora Formation in northern Kenya. The basis for correlation between the two formations is the distinctive chemistry of the tuffs, but systematic chemical variation within some tuffs invalidates some statistical correlation techniques. Here chemical analysis of glass separates and minerals from tuffs of the Shungura and Usno Formations are presented which may allow further ties to be established when data become available on other tuffs of the Koobi Fora Formation. The tuffs consist primarily of glass, but also contain phenocrysts of anorthoclase, hedenbergitic pyroxene, sodic amphibole, ilmenite, titanomagnetite, chevkinite, quartz, zircon, and rarely orthopyroxene and plagioclase. The glasses show evidence of alkali loss during hydration, and are not now peralkaline, although it is likely that they were initially. The source volcanoes were most likely situated within the Ethiopian rift valley, or on its margins.

Thermal conductivity of silicic tuffs: predictive formalism and comparison with preliminary experimental results

International Nuclear Information System (INIS)

Lappin, A. R.

1980-07-01

Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m 0 C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed

Infiltration and Seepage Through Fractured Welded Tuff

Energy Technology Data Exchange (ETDEWEB)

T.A. Ghezzehei; P.F. Dobson; J.A. Rodriguez; P.J. Cook

2006-06-20

The Nopal I mine in Pena Blanca, Chihuahua, Mexico, contains a uranium ore deposit within fractured tuff. Previous mining activities exposed a level ground surface 8 m above an excavated mining adit. In this paper, we report results of ongoing research to understand and model percolation through the fractured tuff and seepage into a mined adit both of which are important processes for the performance of the proposed nuclear waste repository at Yucca Mountain. Travel of water plumes was modeled using one-dimensional numerical and analytical approaches. Most of the hydrologic properly estimates were calculated from mean fracture apertures and fracture density. Based on the modeling results, we presented constraints for the arrival time and temporal pattern of seepage at the adit.

Infiltration and Seepage Through Fractured Welded Tuff

International Nuclear Information System (INIS)

T.A. Ghezzehei; P.F. Dobson; J.A. Rodriguez; P.J. Cook

2006-01-01

The Nopal I mine in Pena Blanca, Chihuahua, Mexico, contains a uranium ore deposit within fractured tuff. Previous mining activities exposed a level ground surface 8 m above an excavated mining adit. In this paper, we report results of ongoing research to understand and model percolation through the fractured tuff and seepage into a mined adit both of which are important processes for the performance of the proposed nuclear waste repository at Yucca Mountain. Travel of water plumes was modeled using one-dimensional numerical and analytical approaches. Most of the hydrologic properly estimates were calculated from mean fracture apertures and fracture density. Based on the modeling results, we presented constraints for the arrival time and temporal pattern of seepage at the adit

Initial Q-list for the prospective Yucca Mountain repository based on items important to safety and waste isolation

International Nuclear Information System (INIS)

Laub, T.W.; Jardine, L.J.

1987-01-01

A method for identifying items important to safety based on a probabilistic risk assessment approach was developed and implemented for the conceptual design of the Yucca Mountain repository. No items were classified as important to safety; however, six items were classified as potentially important to safety. These were the shipping cask, the cranes and the truck or rail-care vehicle stops in the cask receiving and preparation area, the hot cell structure of the waste packaging hot cells, the cranes in the waste packaging hot cells, and the waste-handling building fire protection system. In addition, a method for identifying items important to waste isolation was developed and implemented. Two hydrogeologic units of the Yucca Mountain site were classified as important to waste isolation: the Calico Hills nonwelded zeolitic unit and the Calico Hills nonwelded vitric unit. The preliminary Q-list for the Yucca Mountain repository is comprised of the two units of the site classified as important to waste isolation and contains no items important to safety

New three-dimensional far-field potential repository thermomechanical calculations

International Nuclear Information System (INIS)

Hardy, M.P.; Bai, M.; Goodrich, R.R.; Lin, M.; Carlisle, S.; Bauer, S.J.

1993-03-01

The thermomechanical effect on the exploratory ramps, drifts, and shafts as a result of high-level nuclear waste disposal is examined using a three-dimensional thermo-elastic model. The repository layout modeled is based on the use of mechanical mining of all excavations with equivalent waste emplacement areal power densities of 57 and 80 kW/acre. Predicted temperatures and stress changes for the north and south access drifts, east main drift, east-west exploratory drift, the north and south Calico Hills access ramps, the Calico Hills north-south exploratory drift, and the optional exploratory studies facility and man and materials shafts are presented for times 10, 35, 50, 100, 300, 500, 1000, 2000, 5000, and 10,000 years after the start of waste emplacement. The study indicates that the east-west exploratory drift at the repository horizon is subject to the highest thermomechanical impact because it is located closest the buried waste canisters. For most exploratory openings, the thermally induced temperatures and stresses tend to reach the maximum magnitudes at approximately 1000 years after waste emplacement

Initial Q-list for the prospective Yucca Mountain repository based on items important to safety and waste isolation

International Nuclear Information System (INIS)

Laub, T.W.; Jardine, L.J.

1987-01-01

A method for identifying items important to safety based on a probabilistic risk assessment approach was developed and implemented for the conceptual design of the Yucca Mountain repository. No items were classified as important to safety; however, six items were classified as potentially important to safety. These were the shipping cask, the cranes and the truck or rail-car vehicle stops in the cask receiving and preparation area, the hot cell structure of the waste packaging hot cells, the cranes in the waste packaging hot cells, and the waste-handling building fire protection system. In addition, a method for identifying items important to waste isolation was developed and implemented. Two hydrogeologic units of the Yucca Mountain site were classified as important to waste isolation: the Calico Hills nonwelded zeolitic unit and the Calico Hills nonwelded vitric unit. The preliminary Q-list for the Yucca Mountain repository is comprised of the two units of the site classified as important to waste isolation and contains no items important to safety

Actinide transport in Topopah Spring Tuff: Pore size, particle size, and diffusion

International Nuclear Information System (INIS)

Buchholtz ten Brink, M.; Phinney, D.L.; Smith, D.K.

1991-04-01

Diffusive transport rates for aqueous species in a porous medium are a function of sorption, molecular diffusion, and sample tortuosity. With heterogeneous natural samples, an understanding of the effect of multiple transport paths and sorption mechanisms is particularly important since a small amount of radioisotope traveling via a faster-than-anticipated transport path may invalidate the predictions of transport codes which assume average behavior. Static-diffusion experiments using aqueous 238 U tracer in tuff indicated that U transport was faster in regions of greater porosity and that apparent diffusion coefficients depended on the scale (m or μm) over which concentration gradients were measured in Topopah Spring Tuff. If a significant fraction of actinides in high-level waste are released to the environment in forms that do not sorb to the matrix, they may be similarly transported along fast paths in porous regions of the tuff. To test this, aqueous diffusion rates in tuff were measured for 238 U and 239 Pu leached from doped glass. Measured transport rates and patterns were consistent in both systems with a dual-porosity transported moeld. In addition, filtration or channelling of actinides associated with colloidal particles may significantly affect the radionuclide transport rate in Topopah Spring tuff. 9 refs., 7 figs

Preliminary survey of tuff distribution in Esmeralda, Nye, and Lincoln Counties, Nevada

International Nuclear Information System (INIS)

Smith, G.V.; Pink, T.S.; Lawrence, J.R.; Woodward, L.A.; Keil, K.; Lappin, A.R.

1981-02-01

This report inventories the surface distribution of silicic tuffs in Nye, Esmeralda, and Lincoln Counties, NV, based on a review of available literature. The inventory was taken to provide a data base in evaluating tuff sites for the disposal of high-level nuclear waste. Silicic ash-flow tuffs that are about 11 to 34 million years (my) old are widespread in these counties. These rocks are locally deformed by right-lateral movement along Walker Lane and the Las Vegas Shear Zone, and left-lateral movement along a zone from near the Nevada Test Site (NTS) to the Utah border, and are commonly offset by steeply dipping normal faults. The normal faults that bound horsts, grabens, and tilted-fault blocks of the Basin-and-Range Province began to form 30 my ago; some are still active. Tuff distribution is discussed on a regional basis. Tuff thicknesses and alterations, structural complexity, and proximity to recent faulting, recent volcanism, and mineral resources are discussed for each area. Although the literature on which it is based is often incomplete and sketchy, this report is intended to serve as a basis for future, more detailed work that includes initial field inspection, detailed field and laboratory studies, and extrapolations to the subsurface

TBM performance prediction in Yucca Mountain welded tuff from linear cutter tests

International Nuclear Information System (INIS)

Gertsch, R.; Ozdemir, L.; Gertsch, L.

1992-01-01

This paper discusses performance prediction which were developed for tunnel boring machines operating in welded tuff for the construction of the experimental study facility and the potential nuclear waste repository at Yucca Mountain. The predictions were based on test data obtained from an extensive series of linear cutting tests performed on samples of Topopah String welded tuff from the Yucca Mountain Project site. Using the cutter force, spacing, and penetration data from the experimental program, the thrust, torque, power, and rate of penetration were estimated for a 25 ft diameter tunnel boring machine (TBM) operating in welded tuff. The result show that the Topopah Spring welded tuff (TSw2) can be excavated at relatively high rates of advance with state-of-the-art TBMs. The result also show, however, that the TBM torque and power requirements will be higher than estimated based on rock physical properties and past tunneling experience in rock formations of similar strength

40Ar/39Ar age spectra from the KBS Tuff, Koobi Fora Formation

International Nuclear Information System (INIS)

McDougall, I.

1981-01-01

40 Ar/ 39 Ar age spectra on anorthoclase phenocrysts from three pumice clasts in the KBS Tuff yield nearly ideal flat patterns, providing good evidence that the samples have remained undisturbed since crystallization. The ages are concordant at 1.88 = 0.02 Myr, and confirm that the KBS Tuff, a key marker bed in the Koobi Fora Formation, northern Kenya, is now very well dated. These results resolve the conflict between earlier 40 Ar/ 39 Ar and conventional K-Ar dating measurements on the KBS Tuff. (author)

40Ar/39Ar age spectra from the KBS Tuff, Koobi Fora Formation.

Science.gov (United States)

McDougall, Ian

1981-11-12

40 Ar/ 39 Ar age spectra on anorthoclase phenocrysts from three pumice clasts in the KBS Tuff yield nearly ideal flat patterns, providing good evidence that the samples have remained undisturbed since crystallization. The ages are concordant at 1.88±0.02 Myr, and confirm that the KBS Tuff, a key marker bed in the Koobi Fora Formation, northern Kenya, is now very well dated. These results resolve the conflict between earlier 40 Ar/ 39 Ar and conventional K-Ar dating measurements on the KBS Tuff.

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.A. [Sandia National Labs., Albuquerque, NM (United States); Case, J.B.; Tyburski, J.R. [I. T. Corp., Albuquerque, NM (United States)

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application.

Hydraulic characterization of hydrothermally altered Nopal tuff

Energy Technology Data Exchange (ETDEWEB)

Green, R.T.; Meyer-James, K.A. [Southwest Research Institute, San Antonio, TX (United States); Rice, G. [George Rice and Associates, San Antonio, TX (United States)

1995-07-01

Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow.

Hydraulic characterization of hydrothermally altered Nopal tuff

International Nuclear Information System (INIS)

Green, R.T.; Meyer-James, K.A.; Rice, G.

1995-07-01

Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow

Low temperature spent fuel oxidation under tuff repository conditions

International Nuclear Information System (INIS)

Einziger, R.E.; Woodley, R.E.

1985-01-01

The Nevada Nuclear Waste Storage Investigations Project is studying the suitability of tuffaceous rocks at Yucca Mountain, Nye County, Nevada, for high level waste disposal. The oxidation state of LWR spent fuel in a tuff repository may be a significant factor in determining its ability to inhibit radionuclide migration. Long term exposure at low temperatures to the moist air expected in a tuff repository is expected to increase the oxidation state of the fuel. A program is underway to determine the spent fuel oxidation mechanisms which might be active in a tuff repository. Initial work involves a series of TGA experiments to determine the effectiveness of the technique and to obtain preliminary oxidation data. Tests were run at 200 0 C and 225 0 C for as long as 720 hours. Grain boundary diffusion appears to open up a greater surface area for oxidation prior to onset of bulk diffusion. Temperature strongly influences the oxidation rates. The effect of moisture is small but readily measurable. 25 refs., 7 figs., 4 tabs

TRM performance prediction in Yucca Mountain welded tuff from linear cutter tests

International Nuclear Information System (INIS)

Gertsch, R.; Ozdemir, L.; Gertsch, L.

1992-01-01

Performance predictions were developed for tunnel boring machines operating in welded tuff for the construction of the experimental study facility and the potential nuclear waste repository at Yucca Mountain. The predictions were based on test data obtained from an extensive series of linear cutting tests performed on samples of Topopah Spring welded tuff from the Yucca Mountain Project site. Using the cutter force, spacing, and penetration data from the experimental program, the thrust, torque, power, and rate of penetration were estimated for a 25 ft diameter tunnel boring machine (TBM) operating in welded tuff. Guidelines were developed for the optimal design of the TBM cutterhead to achieve high production rates at the lowest possible excavation costs. The results show that the Topopah Spring welded tuff (TSw2) can be excavated at relatively high rates of advance with state-of-the-art TBMs. The results also show, however, that the TBM torque and power requirements will be higher than estimated based on rock physical properties and past tunneling experience in rock formations of similar strength

Parks of Chapel Hill

Data.gov (United States)

Town of Chapel Hill, North Carolina — Hours, location, and amenity information for Chapel Hill parks as shown on the Town of Chapel Hill's website. Includes a map with points for each park location.

Chloride Diffusion and Acid Resistance of Concrete Containing Zeolite and Tuff as Partial Replacements of Cement and Sand.

Science.gov (United States)

Mohseni, Ehsan; Tang, Waiching; Cui, Hongzhi

2017-03-31

In this paper, the properties of concrete containing zeolite and tuff as partial replacements of cement and sand were studied. The compressive strength, water absorption, chloride ion diffusion and resistance to acid environments of concretes made with zeolite at proportions of 10% and 15% of binder and tuff at ratios of 5%, 10% and 15% of fine aggregate were investigated. The results showed that the compressive strength of samples with zeolite and tuff increased considerably. In general, the concrete strength increased with increasing tuff content, and the strength was further improved when cement was replaced by zeolite. According to the water absorption results, specimens with zeolite showed the lowest water absorption values. With the incorporation of tuff and zeolite, the chloride resistance of specimens was enhanced significantly. In terms of the water absorption and chloride diffusion results, the most favorable replacement of cement and sand was 10% zeolite and 15% tuff, respectively. However, the resistance to acid attack reduced due to the absorbing characteristic and calcareous nature of the tuff.

Distribution of rubidium, strontium, and zirconium in tuff from two deep coreholes at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Spengler, R.W.; Peterman, Z.E.

1991-01-01

Variations in concentrations of trace elements Rb, Sr, and Zr within the sequence of high-silica tuff and dacitic lava beneath Yucca Mountain reflect both primary composition and secondary alteration. Rb and K concentrations have parallel trends. Rb concentrations are significantly lower within intervals containing zeolitic nonwelded to partially welded and bedded tuffs and are higher in thick moderately to densely welded zones. Sr concentrations increase with depth from about 30 parts per million (ppM) in the Topopah Spring Member of the Paintbrush Tuff to almost 300 ppM in the older tuffs. Zr concentrations are about 100 ppM in the Topopah Spring Member and also increase with depth to about 150 ppM in the Lithic Ridge Tuff and upper part of the older tuffs. Conspicuous local high concentrations of Sr in the lower part of the Tram Member, in the dacite lava, and in unit c of the older tuffs in USW G-1, and in the densely welded zone of the Bullfrog Member in USW GU-3/G-3 closely correlate with high concentrations of less-mobile Zr and may reflect either primary composition or elemental redistribution resulting largely from smectitic alteration. Initial 87 Sr/ 86 Sr values from composite samples increase upward in units above the Bullfrog Member of the Crater Flat Tuff. The progressive tenfold increase in Sr with depth coupled with the similarity of initial 87 Sr/ 86 Sr values within the Bullfrog Member and older units to those of Paleozoic marine carbonates are consistent with a massive influx or Sr from water derived from a Paleozoic carbonate aquifer. 23 refs., 4 figs., 1 tab

High-temperature, large-volume, lavalike ash-flow tuffs without calderas in southwestern Idaho

Science.gov (United States)

Ekren, E.B.; McIntyre, David H.; Bennett, Earl H.

1984-01-01

Rhyolitic rocks were erupted from vents in and adjacent to the Owyhee Mountains and Owyhee Plateau of southwestern Idaho from 16 m.y. ago to about 10 m.y. ago. They were deposited on a highly irregular surface developed on a variety of basement rocks that include granitic rocks of Cretaceous age, quartz latite and rhyodacite tuffs and lava flows of Eocene age, andesitic and basaltic lava flows of Oligocene age, and latitic and basaltic lava flows of early Miocene age. The rhyolitic rocks are principally welded tuffs that, regardless of their source, have one feature in common-namely internal characteristics indicating en-masse, viscous lavalike flowage. The flowage features commonly include considerable thicknesses of flow breccia at the bases of various cooling units. On the basis of the tabular nature of the rhyolitic deposits, their broad areal extents, and the local preservation of pyroclastic textures at the bases, tops, and distal ends of some of the deposits, we have concluded that the rocks were emplaced as ash flows at extremely high temperatures and that they coalesced to liquids before final emplacement and cooling. Temperatures of l090?C and higher are indicated by iron-titanium oxide compositions. Rhyolites that are about 16 m.y. old are preserved mostly in the downdropped eastern and western flanks of the Silver City Range and they are inferred to have been erupted from the Silver City Range. They rarely contain more than about 2 percent phenocrysts that consist of quartz and subequal amounts of plagioclase and alkali feldspar; commonly, they contain biotite, and they are the only rhyolitic rocks in the area to do so. The several rhyolitic units that are 14 m.y. to about 10 m.y. old contain only pyroxene-principally ferriferous and intermediate pigeonites-as mafic constituents. The rhyolites of the Silver City Range comprise many cooling units, none of which can be traced for great distances. Rocks erupted from the Owyhee Plateau include two sequences

Version I of the users manual for the Tuff Data Base Interface

International Nuclear Information System (INIS)

Langkopf, B.S.; Satter, B.J.; Welch, E.P.

1985-04-01

The Nevada Nuclear Waste Storage Investigations (NNWSI) project, managed by the Nevada Operations Office of the US Department of Energy, is investigating the feasibility of locating a repository at Yucca Mountain on and adjacent to the Nevada Test Site (NTS) in southern Nevada. A part of this investigation includes obtaining physical properties from laboratory tests on samples from Yucca Mountain and field tests of the in situ tuffs at Yucca Mountain. A computerized data base has been developed to store this data in a centralized location. The data base is stored on the Cyber 170/855 computer at Sandia using the System 2000 Data Base Management software. A user-friendly interface, the Tuff Data Base Interface, is being developed to allow NNWSI participants to retrieve information from the Tuff Data Base directly. The Interface gives NNWSI users a great deal of flexibility in retrieving portions of the Data Base. This report is an interim users manual for the Tuff Data Base Interface, as of August 1984. It gives basic instructions on accessing the Sandia computing system and explains the Interface on a question-by-question basis

The behavior of biogenic silica-rich rocks and volcanic tuffs as pozzolanic additives in cement

Science.gov (United States)

Fragoulis, Dimitris; Stamatakis, Michael; Anastasatou, Marianthi

2015-04-01

Cements currently produced, include a variety of pozzolanic materials, aiming for lower clinker addition and utilization of vast deposits of certain raw materials and/or mining wastes and byproducts. The major naturally occurring pozzolanic materials include glassy tuffs, zeolitic tuffs, diatomites and volcanic lavas rich in glassy phase, such as perlites. Therefore, based on the available raw materials in different locations, the cement composition might vary according to the accessibility of efficient pozzolanic materials. In the present investigation, the behavior of pozzolanic cements produced with representative samples of the aforementioned materials was studied, following the characterization of the implemented pozzolanas with respect to their chemical and mineralogical characteristics. Laboratory cements were produced by co-grinding 75% clinker, 5% gypsum and 20% pozzolana, for the same period of time (45 min). Regarding pozzolanic materials, four different types of pozzolanas were utilized namely, diatomite, perlite, zeolite tuff and glassy tuff. More specifically, two diatomite samples originated from Australia and Greece, with high and low reactive silica content respectively, two perlite samples originated from Turkey and from Milos Island, Greece, with different reactive silica contents, a zeolite tuff sample originated from Turkey and a glassy tuff sample originated from Milos Island, Greece. The above pozzolana samples, which were ground in the laboratory ball mill for cement production performed differently during grinding and that was reflected upon the specific surface area (cm2/gr) values. The perlites and the glassy tuff were the hardest to grind, whereas, the zeolite tuff and the Australian diatomite were the easiest ones. However, the exceedingly high specific surface area of the Australian diatomite renders cement difficult to transport and tricky to use for concrete manufacturing, due to the high water demand of the cement mixture. Regarding

Fracture coatings in Topopah Spring Tuff along drill hole wash

International Nuclear Information System (INIS)

Carlos, B.A.; Chipera, S.J.; Bish, D.L.

1994-01-01

Fracture-lining minerals are being studied as part of site characterization to determine the suitability of Yucca Mountain, Nevada as a potential high level nuclear waste repository. Fracture coatings in the Paintbrush Group provide information on potential flow paths above the water table both toward and away from the potential repository and provide information on the distribution of fracture-lining minerals needed to model thermal effects of waste emplacement. Fracture coatings within the predominantly non-zeolitic Paintbrush Group vary both with depth and laterally across Yucca Mountain, whereas fracture coatings in tuffs below the Paintbrush Group are related to the mineralogy of the tuffs and follow a consistent pattern of distribution with predominantly quartz, calcite, and manganese oxides in the devitrified intervals and mordenite and clinoptilolite in the zeolitic intervals. The zeolites stellerite and heulandite are more abundant in fractures in the Topopah Spring Tuff in drill holes USW G-1 and UE-25 a number-sign l, located along Drill Hole Wash (at the northern end of Yucca Mountain) than in core from other parts of Yucca Mountain. Buesch et al. (2) present evidence for a complex fault system along Drill Hole Wash. To investigate the possibility that the abundant fracture-lining zeolites in USW G-1 and UE-25 a number-sign 1 are related to the Drill Hole Wash fault, the Topopah Spring Tuff was examined in drill cores from USW UZ-14, USW G-1, USW NRG-7/7a, and UE-25 a number-sign l

Triaxial- and uniaxial-compression testing methods developed for extraction of pore water from unsaturated tuff, Yucca Mountain, Nevada

Energy Technology Data Exchange (ETDEWEB)

Mower, T.E.; Higgins, J.D. [Colorado School of Mines, Golden, CO (USA). Dept. of Geology and Geological Engineering; Yang, I.C. [Geological Survey, Denver, CO (USA). Water Resources Div.

1989-12-31

To support the study of hydrologic system in the unsaturated zone at Yucca Mountain, Nevada, two extraction methods were examined to obtain representative, uncontaminated pore-water samples from unsaturated tuff. Results indicate that triaxial compression, which uses a standard cell, can remove pore water from nonwelded tuff that has an initial moisture content greater than 11% by weight; uniaxial compression, which uses a specifically fabricated cell, can extract pore water from nonwelded tuff that has an initial moisture content greater than 8% and from welded tuff that has an initial moisture content greater than 6.5%. For the ambient moisture conditions of Yucca Mountain tuffs, uniaxial compression is the most efficient method of pore-water extraction. 12 refs., 7 figs., 2 tabs.

Triaxial-compression extraction of pore water from unsaturated tuff, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Yang, I.C.; Turner, A.K.; Sayre, T.M.; Montazer, P.

1988-01-01

The purpose of this experiment was to design and validate methods for extracting uncontaminated pore water from nonwelded parts of this tuff. Pore water is needed for chemical analysis to help characterize the local hydrologic system. A standard Hoek-Franklin triaxial cell was modified to create a chemically inert pore-water-extraction system. Experimentation was designed to determine the optimum stress and duration of triaxial compression for efficient extraction of uncontaminated pore water. Experimental stress paths consisted of a series of increasing stress levels. Trial axial stress levels ranged from 41 to 190 megapascals with lateral confining stresses of 34 to 69 megapascals. The duration of compression at any given stress level lasted from 10 minutes to 15 hours. A total of 40 experimental extraction trials were made. Tuff samples used in these tests were collected from drill-hole core from the Paintbrush nonwelded unit at Yucca Mountain. Pore water was extracted from tuff samples that had a water content greater than 13 percent by weight. Two stress paths have been determined to be applicable for future pore-water extraction from nonwelded tuff at Yucca Mountain. The initial water content of a sample affects the selection of an appropriate period of compression. 39 refs., 55 figs

K-Ar age estimate for the KBS Tuff, East Turkana, Kenya

International Nuclear Information System (INIS)

McDougall, I.; Maier, R.; Sutherland-Hawkes, P.; Gleadow, A.J.W.

1980-01-01

Stone tools and numerous vertebrate fossils including hominids, have been found in close stratigraphic proximity to the KBS Tuff, whose age has been the subject of much debate. Concordant K-Ar ages, averaging 1.89 +- 0.01 Myr, are reported on anorthoclase phenocrysts from 13 pumice clasts collected from within the KBS Tuff or its correlatives. It is believed that this age is the best estimate currently available for the time of formation of this important marker horizon within the East Turkana Basin. (author)

Stonewall Mountain Volcanic Center, southern Nevada: Stratigraphic, structural, and facies relations of outflow sheets, near-vent tuffs, and intracaldera units

Science.gov (United States)

Weiss, Steven I.; Noble, Donald C.

1989-05-01

Directly south and southeast of Stonewall Mountain, Nevada, a depression and north facing caldera scarp were formed during and(or) after eruption of the Spearhead Member of the late Miocene Stonewall Flat Tuff. Abundant large lithic and juvenile blocks are present in the Spearhead Member within 0.5 km of this topographic margin but absent elsewhere in the ash-flow sheet, consistent with eruption from vents in the Stonewall Mountain area. Within about 100,000 years, comendite tuff of the overlying Civet Cat Canyon Member of the Stonewall Flat Tuff buried the depression and associated scarp. The Civet Cat Canyon Member is traceable continuously to the north from an outflow sheet capping northwestern Pahute Mesa, into near-vent tuff on the southeastern flank of Stonewall Mountain. Proximal outflow-sheet tuff locally exhibits strong rheomorphic disruption and is overlain without a cooling break by surge, flow, and fall deposits of trachytic composition. Much of Stonewall Mountain is composed of welded tuff and megabreccia interpreted as intracaldera tuff of the Civet Cat Canyon Member, strongly suggesting that the vent area of the member was largely within Stonewall Mountain. Welded tuff of trachytic composition comprises an important part of the intracaldera Civet Cat Canyon Member, which was intruded by dikes and plugs of trachyte and rhyolite. Juvenile inclusions of basalt dispersed in near-vent facies trachyte tuff provide direct evidence for the high-level involvement of basaltic magma in the evolution of the highly potassic Stonewall Mountain center. Complex discordant compaction foliations and the widespread presence of megabreccia within the intracaldera tuff suggest, following Foley (1978), cauldron subsidence by piecemeal collapse during eruption of the Civet Cat Canyon Member. The elevation of intracaldera tuff and intrusions in Stonewall Mountain above the surrounding ashflow sheet suggests a significant amount of magmatic uplift, perhaps involving the

Biogas cleaning and upgrading with natural zeolites from tuffs.

Science.gov (United States)

Paolini, Valerio; Petracchini, Francesco; Guerriero, Ettore; Bencini, Alessandro; Drigo, Serena

2016-01-01

CO2 adsorption on synthetic zeolites has become a consolidated approach for biogas upgrading to biomethane. As an alternative to synthetic zeolites, tuff waste from building industry was investigated in this study: indeed, this material is available at a low price and contains a high fraction of natural zeolites. A selective adsorption of CO2 and H2S towards CH4 was confirmed, allowing to obtain a high-purity biomethane (CO2 biogas samples were used, and no significant effects due to biogas impurities (e.g. humidity, dust, moisture, etc.) were observed. Thermal and vacuum regenerations were also optimized and confirmed to be possible, without significant variations in efficiency. Hence, natural zeolites from tuffs may successfully be used in a pressure/vacuum swing adsorption process.

Evaporative water loss from welded tuff

International Nuclear Information System (INIS)

Hadley, G.R.; Turner, J.R. Jr.

1980-04-01

Welded tuff is one of the many candidate rocks presently being considered as a host medium for the disposal of radioactive waste. In the case where the disposal site lies above the water table, the host rock will in general be only partially saturated. This condition leads to a number of mass transfer processes of interest, including evaporative drying, two-phase water flow due to pressure gradients, capillary movement, plus others. Although these processes have all been known about for decades, it is not clear at this time what the relative importance of each is with regard to geologic media in a waste disposal environment. In particular, there seems to be no data available for tuff that would allow an investigator to sort out mechanisms. This work is intended to be a start in that direction. This paper reports the measurement of water loss rate for welded tuff at various temperatures due to the action of evaporative drying. The initial saturation was unknown, but the average initial water content was found to be 7% by weight. The resulting data show that the water loss rate declines monotonically with time at a given temperature and increases with increasing temperature as expected. Somewhat surprising, however, is the fact that over 90% of the water from a sample was lost by evaporation at room temperature within 72 hours. All the water loss data, including that taken at temperatures as high as 150 0 C, are explained to within a factor of two by a simple evaporation front model. The latter assumes the water is lost by the molecular diffusion of water vapor from a receding evaporation front. The motion of the evaporation front seems to depend on mass balance rather than energy balance. Capillary forces and the resulting liquid diffusion are evidently not strong enough to wash out the evaporation front, since the front model seems to fit the data well

Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

Science.gov (United States)

Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

2011-10-01

We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

The one-dimensional compression method for extraction of pore water from unsaturated tuff and effects on pore-water chemistry

Energy Technology Data Exchange (ETDEWEB)

Higgins, J.D.; Burger, P.A. [Colorado School of Mines, Golden, CO (United States); Yang, L.C. [Geological Survey, Denver, CO (United States)

1997-12-31

Study of the hydrologic system at Yucca Mountain, Nevada, requires extraction of pore-water samples from unsaturated tuff bedrock. Two generations of compression cells have been designed and tested for extracting representative, unaltered pore-water samples from unsaturated tuff cores. The one-dimensional compression cell has a maximum compressive stress rating of 552 MPa. Results from 86 tests show that the minimum degree of saturation for successful extraction of pore water was about 14% for non welded tuff and about 61% for densely welded tuff. The high-pressure, one-dimensional compression cell has a maximum compressive stress rating of 827 MPa. Results from 109 tests show that the minimum degree of saturation for successful extraction of pore water was about 7.5% for non welded tuff and about 34% for densely welded tuff. Geochemical analyses show that, in general, there is a decrease in ion concentration of pore waters as extraction pressures increase. Only small changes in pore-water composition occur during the one-dimensional extraction test.

Hydraulic Characterization of Overpressured Tuffs in Central Yucca Flat, Nevada Test Site, Nye County, Nevada

Energy Technology Data Exchange (ETDEWEB)

K.J. Halford; R.J. Laczniak; D.L. Galloway

2005-10-07

A sequence of buried, bedded, air-fall tuffs has been used extensively as a host medium for underground nuclear tests detonated in the central part of Yucca Flat at the Nevada Test Site. Water levels within these bedded tuffs have been elevated hundreds of meters in areas where underground nuclear tests were detonated below the water table. Changes in the ground-water levels within these tuffs and changes in the rate and distribution of land-surface subsidence above these tuffs indicate that pore-fluid pressures have been slowly depressurizing since the cessation of nuclear testing in 1992. Declines in ground-water levels concurrent with regional land subsidence are explained by poroelastic deformation accompanying ground-water flow as fluids pressurized by underground nuclear detonations drain from the host tuffs into the overlying water table and underlying regional carbonate aquifer. A hydraulic conductivity of about 3 x 10-6 m/d and a specific storage of 9 x 10-6 m-1 are estimated using ground-water flow models. Cross-sectional and three-dimensional ground-water flow models were calibrated to measured water levels and to land-subsidence rates measured using Interferometric Synthetic Aperture Radar. Model results are consistent and indicate that about 2 million m3 of ground water flowed from the tuffs to the carbonate rock as a result of pressurization caused by underground nuclear testing. The annual rate of inflow into the carbonate rock averaged about 0.008 m/yr between 1962 and 2005, and declined from 0.005 m/yr in 2005 to 0.0005 m/yr by 2300.

Evenly-spaced columns in the Bishop Tuff as relicts of hydrothermal convection

Science.gov (United States)

Randolph-Flagg, N. G.; Breen, S. J.; Hernandez, A.; Self, S.; Manga, M.

2015-12-01

A few square km of the Bishop Tuff in eastern California, USA have evenly spaced erosional columns. These columns are more resistant to erosion due to the precipitation of the low-temperature zeolite (120-200 ºC), mordenite, which is not found in the surrounding tuff. Similar features observed in the Bandelier Tuff were hypothesized to form when cold water from above infiltrated into the still-hot tuff interior. This water would become gravitationally unstable and produced convection with steam upwellings and liquid water downwellings. These downwellings became cemented with mordenite while the upwellings were too dry for chemical reactions. We use two methods to quantitatively assess this hypothesis. First, scaling that ignores the effects of latent heat and mineral precipitation suggests the Rayleigh number (Ra, a measure of convective vigor) for this system is ~103 well above the critical Ra of 4π2. Second, to account for the effect of multiphase flow and latent heat, we use two-dimensional numerical models in the finite difference code HYDROTHERM. We find that the geometry of flow is consistent with field observations and confirm that geometry is sensitive to permeability and topography. These tests suggest a few things about low-pressure hydrothermal systems. 1) The geometry of at least some convection appears to be broadly captured by linear stability theory that ignores reactive transport, heterogeneity of host rock, and the effects of latent heat. 2) Topographic flow sets the wavelength of convection meaning that these columns formed somewhere without topography—probably a lake. Finally, these observations imply a wet paleoclimate in the Eastern Sierra namely that, in the aftermath of the Long Valley eruption, either rain or snow was able to pool in the caldera before the tuff cooled on the order of a hundred years after the eruption.

Performance prediction of mechanical excavators from linear cutter tests on Yucca Mountain welded tuffs

International Nuclear Information System (INIS)

Gertsch, R.; Ozdemir, L.

1992-09-01

The performances of mechanical excavators are predicted for excavations in welded tuff. Emphasis is given to tunnel boring machine evaluations based on linear cutting machine test data obtained on samples of Topopah Spring welded tuff. The tests involve measurement of forces as cutters are applied to the rock surface at certain spacing and penetrations. Two disc and two point-attack cutters representing currently available technology are thus evaluated. The performance predictions based on these direct experimental measurements are believed to be more accurate than any previous values for mechanical excavation of welded tuff. The calculations of performance are predicated on minimizing the amount of energy required to excavate the welded tuff. Specific energy decreases with increasing spacing and penetration, and reaches its lowest at the widest spacing and deepest penetration used in this test program. Using the force, spacing, and penetration data from this experimental program, the thrust, torque, power, and rate of penetration are calculated for several types of mechanical excavators. The results of this study show that the candidate excavators will require higher torque and power than heretofore estimated

Performance testing of waste forms in a tuff environment

International Nuclear Information System (INIS)

Oversby, V.M.

1983-11-01

This paper describes experimental work conducted to establish the chemical composition of water which will have reacted with Topopah Spring Member tuff prior to contact with waste packages. The experimental program to determine the behavior of spent fuel and borosilicate glass in the presence of this water is then described. Preliminary results of experiments using spent fuel segments with defects in the Zircaloy cladding are presented. Some results from parametric testing of a borosilicate glass with tuff and 304L stainless steel are also discussed. Experiments conducted using Topopah Spring tuff and J-13 well water have been conducted to provide an estimate of the post-emplacement environment for waste packages in a repository at Yucca Mountain. The results show that emplacement of waste packages should cause only small changes in the water chemistry and rock mineralogy. The changes in environment should not have any detrimental effects on the performance of metal barriers or waste forms. The NNWSI waste form testing program has provided preliminary results related to the release rate of radionuclides from the waste package. Those results indicate that release rates from both spent fuel and borosilicate glass should be below 1 part in 10 5 per year. Future testing will be directed toward making release rate testing more closely relevant to site specific conditions. 17 references, 7 figures

Bench-scale experimental determination of the thermal diffusivity of crushed tuff

International Nuclear Information System (INIS)

Ryder, E.E.; Finley, R.E.; George, J.T.; Ho, C.K.; Longenbaugh, R.S.; Connolly, J.R.

1996-06-01

A bench-scale experiment was designed and constructed to determine the effective thermal diffusivity of crushed tuff. Crushed tuff particles ranging from 12.5 mm to 37.5 mm (0.5 in. to 1.5 in.) were used to fill a cylindrical volume of 1.58 m 3 at an effective porosity of 0.48. Two iterations of the experiment were completed; the first spanning approximately 502 hours and the second 237 hours. Temperatures near the axial heater reached 700 degrees C, with a significant volume of the test bed exceeding 100 degrees C. Three post-test analysis techniques were used to estimate the thermal diffusivity of the crushed tuff. The first approach used nonlinear parameter estimation linked to a one dimensional radial conduction model to estimate thermal diffusivity from the first 6 hours of test data. The second method used the multiphase TOUGH2 code in conjunction with the first 20 hours of test data not only to estimate the crushed tuffs thermal diffusivity, but also to explore convective behavior within the test bed. Finally, the nonlinear conduction code COYOTE-II was used to determine thermal properties based on 111 hours of cool-down data. The post-test thermal diffusivity estimates of 5.0 x 10-7 m 2 /s to 6.6 x 10-7 m 2 /s were converted to effective thermal conductivities and compared to estimates obtained from published porosity-based relationships. No obvious match between the experimental data and published relationships was found to exist; however, additional data for other particle sizes and porosities are needed

Pena Blanca uranium deposits and ash-flow tuffs relationship

International Nuclear Information System (INIS)

Magonthier, M.

1987-01-01

The Pena Blanca uranium deposits (Chihuahua, Mexico) are associated with a Tertiary sequence of ash-flow tuffs. Stratigraphic control is dominant and uranium mineralization occurs in stratiform and fracture-controlled deposits within 44 My-old units: Nopal Rhyolite and Escuadra Rhyolite. These units consist of highly vapor-phase crystallized ash-flow tuffs. They contain sanidine, quartz and granophyric phenocrysts, and minor ferromagnesian silicates. Nopal and Escuadra units are high-silica alkali-rich rhyolites that have a primary potassic character. The trace-element chemistry shows high concentrations in U-Th-Rb-Cs and low contents in Ba-Sr-Eu. These chemical properties imply a genetic relationship between deposits and host-units. The petrochemical study show that the Nopal Rhyolite and Escuadra Rhyolite are the source of U and of hydrothermal solutions [fr

Mo and Ni Removal from Drinking Water Using Zeolitic Tuff from Jordan

Directory of Open Access Journals (Sweden)

Khalil M. Ibrahim

2016-11-01

Full Text Available Mo and Ni metals could be hazardous in natural waters. The initial Mo and Ni concentration in the sampled domestic drinking water of north Jordan is 550 and 110 μg/L, respectively. The efficiency of using natural faujasite–phillipsite and phillipsite–chabazite tuffs in removing Mo and Ni from contaminated drinking water was tested. Batch experiments using different weights of the adsorbent were conducted at different contact times to determine the optimum conditions. The maximal uptake capacity of Mo from drinking water was equivalent to 440–420 μg/g adsorbent. The maximum removal efficiency of Mo by faujasite–phillipsite, phillipsite–chabazite, and the modified surfactant phillipsite–chabazite tuffs were 80%, 76%, and 78%, respectively. The proportional relationship between contact time and removal efficiency of Ni from water samples was observed. The maximum removal efficiency of Ni by the zeolitic tuffs is up to 90% compared to the original groundwater sample.

A natural analogue for high-level waste in tuff: Chemical analysis and modeling of the Valles site

International Nuclear Information System (INIS)

Stockman, H.W.; Krumhansl, J.L.; Ho, C.K.; Kovach, L.; McConnell, V.S.

1995-01-01

The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a high-level waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock Tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, x-ray diffraction, and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and 39 Ar/ 40 Ar isotopic composition. Overall, the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 m of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks

Environmental effects on corrosion in the Tuff repository

International Nuclear Information System (INIS)

Beavers, J.A.; Thompson, N.G.

1990-02-01

Cortest Columbus is investigating the long-term performance of container materials used for high-level waste packages as part of the information needed by the Nuclear Regulatory Commission to assess the Department of Energy's application to construct a geologic repository for high-level radioactive waste. The scope of work consists of employing short-term techniques, to examine a wide range of possible failure modes. Long-term tests are being used to verify and further examine specific failure modes identified as important by the short-term studies. The original focus of the program was on the salt repository but the emphasis was shifted to the Tuff repository. This report summarizes the results of a literature survey performed under Task 1 of the program. The survey focuses on the influence of environmental variables on the corrosion behavior of candidate container materials for the Tuff repository. Environmental variables considered include: radiation, thermal and microbial effects. 80 refs., 44 figs., 44 tabs

Equilibrium sorption of cobalt, cesium, and strontium on Bandelier Tuff: analysis of alternative mathematical modeling

International Nuclear Information System (INIS)

Polzer, W.L.; Fuentes, H.R.; Essington, E.H.; Roensch, F.R.

1985-01-01

Sorption isotherms are derived from batch equilibrium data for cobalt, cesium and strontium on Bandelier Tuff. Experiments were conducted at an average temperature of 23 0 C and equilibrium was defined at 48 hours. The solute concentrations ranged from 0 to 500 mg/L. The radioactive isotopes 60 Co, 137 Cs, and 85 Sr were used to trace the sorption of the stable solutes. The Linear, Langmuir, Freundlich and a Modified Freundlich isotherm equations are evaluated. The Modified Freundlich isotherm equation is validated as a preferred general mathematical tool for representing the sorption of the three solutes. The empirical constants derived from the Modified Freundlich isotherm equation indicate that under dynamic flow conditions strontium will move most rapidly and cobalt least rapidly. On the other hand, chemical dispersion will be greatest for cesium and least for strontium. Hill Plots of the sorption data suggest that in the region of low saturation sorption of all three solutes is impeded by interactions among sorption sites; cobalt exhibits the greatest effect of interactions and strontium shows only a minimal effect. In the saturation region of 50% or more, sorption of cobalt is enhanced slightly by interactions among sorption sites whereas sorption of cesium and strontium appears to be independent of site interactions. 9 references, 4 figures, 2 tables

Corrosion testing of type 304L stainless steel in tuff groundwater environments

International Nuclear Information System (INIS)

Westerman, R.E.; Pitman, S.G.; Haberman, J.H.

1987-11-01

The stress-corrosion cracking (SCC) resistance of Type 304L stainless steel (SS) to elevated temperatures in tuff rock and tuff groundwater environments was determined under irradiated and nonirradiated conditions using U-bend specimens and slow-strain-rate tests. The steel was tested both in the solution-annealed condition and after sensitization heat treatments. The material was found to be susceptible to SCC in both the solution-annealed and solution-annealed-and-sensitized conditions when exposed to an irradiated crushed tuff rock environment containing air and water vapor at 90 0 C. A similar exposure at 50 0 C did not result in failure after a 25-month test duration. Specimens of sensitized 304 SS conditioned with a variety of sensitization heat treatments resisted failure during a test of 1-year duration in which a nonirradiated environment of tuff rock and groundwater held at 200 0 C was allowed to boil to dryness on a cyclical basis. All specimens of sensitized 304 SS exposed to this environment failed. Slow-strain-rate studies were performed on 304L, 304, and 316L SS specimens. The 304L SS was tested in J-13 well water at 150 0 C, and the 316L SS at 95 0 C. Neither material showed evidence of SCC in these tests. Sensitized 304 SS did exhibit SCC in J-13 well water in tests conducted at 150 0 C. 12 refs., 27 figs., 13 tabs

IMPLEMENTASI SANDI HILL UNTUK PENYANDIAN CITRA

Directory of Open Access Journals (Sweden)

JJ Siang

2002-01-01

Full Text Available Hill's code is one of text encoding technique. In this research, Hill's code is extended to image encoding. The image used is BMP 24 bit format. 2x2 and 3x3 matrices is used as a key. The results show that Hill's code is suitable for image whose RGB values vary highly. On the contrary, it is not suitable for less varied RGB images since its original pattern is still persisted in encrypted image. Hill's code for image encoding has also disadvantage in the case that the key matrix is not unique. However, for daily application, with good key matrix, Hill's code can be applied to encode image since it's process only deals with simple matrix operation so it become fast. Abstract in Bahasa Indonesia : Sandi Hill merupakan salah satu teknik penyandian teks. Dalam penelitian ini, pemakaian sandi Hill diperluas dari teks ke citra bertipe BMP 24 bit. Matriks yang dipakai berordo 2x2 dan 3x3. Hasil percobaan menunjukkan bahwa sandi Hill cocok untuk enkripsi citra dengan variasi nilai RGB antar piksel berdekatan yang tinggi (seperti foto, tapi tidak cocok untuk citra dengan variasi nilai RGB yang rendah (seperti gambar kartun karena pola citra asli masih tampak dalam citra sandi. Sandi Hill juga memiliki kelemahan dalam hal tidak tunggalnya matriks kunci yang dapat dipakai. Akan tetapi untuk pemakaian biasa, dengan pemilihan matriks kunci yang baik, sandi Hill dapat dipakai untuk penyandian karena hanya melibatkan operasi matriks biasa sehingga prosesnya relatif cepat. Kata kunci: Sandi Hill, Citra, Relatif Prima.

Modeling of flow through fractured tuff at Fran Ridge

International Nuclear Information System (INIS)

Eaton, R.R.; Ho, C.K.; Glass, R.J.; Nicholl, M.J.; Arnold, B.W.

1996-01-01

Numerical studies have modeled an infiltration experiment at Fran Ridge, using the TOUGH2 code, to aid in the selection of computational models for waste repository performance assessment. This study investigates the capabilities of TOUGH2 to simulate transient flows through highly fractured tuff, and provides a possible means of calibrating hydrologic parameters such as effective fracture aperture and fracture-matrix connectivity. Two distinctly different conceptual models were used in the TOUGH2 code, the dual permeability model and the equivalent continuum model. The field experiments involved the infiltration of dyed ponded water in highly fractured tuff. The infiltration observed in the experiment was subsequently modeled using Fran Ridge fracture frequencies, obtained during post-experiment site excavation. Comparison of the TOUGH2 results obtained using the two conceptual models gives insight into their relative strengths and weaknesses

Methodology for determining time-dependent mechanical properties of tuff subjected to near-field repository conditions

International Nuclear Information System (INIS)

Blacic, J.D.; Andersen, R.

1983-01-01

We have established a methodology to determine the time dependence of strength and transport properties of tuff under conditions appropriate to a nuclear waste repository. Exploratory tests to determine the approximate magnitudes of thermomechanical property changes are nearly complete. In this report we describe the capabilities of an apparatus designed to precisely measure the time-dependent deformation and permeability of tuff at simulated repository conditions. Preliminary tests with this new apparatus indicate that microclastic creep failure of tuff occurs over a narrow strain range with little precursory Tertiary creep behavior. In one test, deformation under conditions of slowly decreasing effective pressure resulted in failure, whereas some strain indicators showed a decreasing rate of strain

Methodology for determining time-dependent mechanical properties of tuff subjected to near-field repository conditions

Energy Technology Data Exchange (ETDEWEB)

Blacic, J.D.; Andersen, R.

1983-01-01

We have established a methodology to determine the time dependence of strength and transport properties of tuff under conditions appropriate to a nuclear waste repository. Exploratory tests to determine the approximate magnitudes of thermomechanical property changes are nearly complete. In this report we describe the capabilities of an apparatus designed to precisely measure the time-dependent deformation and permeability of tuff at simulated repository conditions. Preliminary tests with this new apparatus indicate that microclastic creep failure of tuff occurs over a narrow strain range with little precursory Tertiary creep behavior. In one test, deformation under conditions of slowly decreasing effective pressure resulted in failure, whereas some strain indicators showed a decreasing rate of strain.

Stress corrosion cracking tests on high-level-waste container materials in simulated tuff repository environments

International Nuclear Information System (INIS)

Abraham, T.; Jain, H.; Soo, P.

1986-06-01

Types 304L, 316L, and 321 austenitic stainless steel and Incoloy 825 are being considered as candidate container materials for emplacing high-level waste in a tuff repository. The stress corrosion cracking susceptibility of these materials under simulated tuff repository conditions was evaluated by using the notched C-ring method. The tests were conducted in boiling synthetic groundwater as well as in the steam/air phase above the boiling solutions. All specimens were in contact with crushed Topopah Spring tuff. The investigation showed that microcracks are frequently observed after testing as a result of stress corrosion cracking or intergranular attack. Results showing changes in water chemistry during test are also presented

Sorption and desorption of remazol yellow by a Fe-zeolitic tuff

International Nuclear Information System (INIS)

Solache R, M. J.; Villalva C, R.; Diaz N, M. C.

2010-01-01

The adsorption of remazol yellow from aqueous solution was evaluated using a Fe-zeolitic tuff. The adsorbent was characterized by scanning electron microscopy, IR spectroscopy and X-ray diffraction. Sorption kinetic and isotherms were determined and the adsorption behavior was analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results, indicating chemisorption on a heterogeneous material. The regeneration of the material was best accomplished by using a H 2 O 2 solution. The sorption capacity of the Fe-zeolitic tuff increased when the saturated samples were treated with a H 2O2 or FeCl 3 solution. (Author)

Sorption and desorption of remazol yellow by a Fe-zeolitic tuff

Energy Technology Data Exchange (ETDEWEB)

Solache R, M. J. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Villalva C, R.; Diaz N, M. C., E-mail: marcos.solache@inin.gob.m [Instituto Tecnologico de Toluca, Division de Estudios del Posgrado, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico)

2010-07-01

The adsorption of remazol yellow from aqueous solution was evaluated using a Fe-zeolitic tuff. The adsorbent was characterized by scanning electron microscopy, IR spectroscopy and X-ray diffraction. Sorption kinetic and isotherms were determined and the adsorption behavior was analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results, indicating chemisorption on a heterogeneous material. The regeneration of the material was best accomplished by using a H{sub 2}O{sub 2} solution. The sorption capacity of the Fe-zeolitic tuff increased when the saturated samples were treated with a H{sub 2O2} or FeCl{sub 3} solution. (Author)

Hill's formula

Energy Technology Data Exchange (ETDEWEB)

Bolotin, Sergey V [Steklov Mathematical Institute, Russian Academy of Sciences, Moscow (Russian Federation); Treschev, Dmitrii V [M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2010-07-27

In his study of periodic orbits of the three-body problem, Hill obtained a formula connecting the characteristic polynomial of the monodromy matrix of a periodic orbit with the infinite determinant of the Hessian of the action functional. A mathematically rigorous definition of the Hill determinant and a proof of Hill's formula were obtained later by Poincare. Here two multidimensional generalizations of Hill's formula are given: for discrete Lagrangian systems (symplectic twist maps) and for continuous Lagrangian systems. Additional aspects appearing in the presence of symmetries or reversibility are discussed. Also studied is the change of the Morse index of a periodic trajectory upon reduction of order in a system with symmetries. Applications are given to the problem of stability of periodic orbits. Bibliography: 34 titles.

The Origin of the Columbia Hills

Science.gov (United States)

Rice, J. W.

2005-12-01

The Columbia Hills form a rugged ridge complex comprised of 7 peaks spanning some 3.5 km in length and reaching a maximum height of 106 m (Husband Hill) above the plains of Spirit's landing site. As of this writing Spirit has been exploring the Columbia Hills for over 440 sols (since sol 156 on June 11, 2004). Thus far the origin of the Columbia Hills has remained elusive despite detailed analysis of numerous rock and soil targets, including outcrops. The chemical differences among the 6 distinct rock classes attest to the lithologic diversity and geologic complexity of the Hills. Origin of the Columbia Hills Several hypothesis have been put forth to explain the origin of the Columbia Hills: Old eroded partially buried impact crater rim(s), central peak, residual intracrater fill material, volcanic construct, wrinkle ridge, delta and or combinations of the above. Observations that support various aspects of these multiple hypotheses will be discussed. Numerous buried craters are observed on the floor of Gusev lending credence to the idea that the Columbia Hills are the remains of an ancient impact crater rim or possibly a central peak. Morphologic evidence of the rim of Thira crater and the Columbia Hills appears to support this hypothesis. The Aeolis region contains numerous craters that contain layered materials in the absence of any major fluvial systems. This could imply that the Columbia Hills are the remnants of a formerly extensive unit(s). Gusev contains many hills scattered across its floor such as Grissom, White, Chaffee and numerous other buttes and mesas that may be remnants of a former extensive intracrater deposit. Another possibility is that the Columbia Hills are composed of volcanic materials (cinder cones and associated ash and lava flows) derived either locally or from Apollinaris Patera located 300 km to the north. Several depressions are located in the Columbia Hills. These features could be calderas but are most likely impact craters. The most

The Hill Chart Calculation for Pelton Runner Models using the HydroHillChart - Pelton Module Software

Directory of Open Access Journals (Sweden)

Adelina Bostan

2015-07-01

Full Text Available The Pelton turbines industrial design is based on the hill chart characteristics obtained by measuring the models. Primary data measurements used to obtain the hill chart can be processed graphically, by hand or by using graphic programs respectively CAD programs; the HydroHillChart - Pelton module software is a specialized tool in achieving the hill chart, using interpolation cubic spline functions. Thereby, based on measurements of several models of Pelton turbines, a computerized library, used to design industrial Pelton turbines can be created. The paper presents the universal characteristics calculated by using the HydroHillChart - Pelton module software for a series of Pelton runners.

Loess Hills of Iowa

Data.gov (United States)

Iowa State University GIS Support and Research Facility — This coverage outlines the boundary of the Loess Hills in Iowa at 1:100,000 scale. Criteria applied to the delineation of the Loess Hills included drainage density,...

Juvenile fragment studies on lapilli tuffs of the Messel maar-diatreme-volcano, Germany: implications for rockmagnetic properties

Science.gov (United States)

Nitzsche, T.; de Wall, H.; Rolf, C.; Schuessler, U.

2006-12-01

In 2001 the 433 m deep Messel 2001 bore hole was drilled in the centre of the Messel Pit, 25 km south of Frankfurt (Germany). Interdisciplinary, geoscientific results obtained from this drilling proved the origin of the circular-shaped basin as a maar-diatreme-structure beneath the surface. Recovered deposits consist of sedimentary rocks (0-240 m) and volcaniclastic rocks such as lapilli tuffs (240-373 m) as well as rocks of the underlying diatreme breccia (373-433 m). The lapilli tuffs, as matter of interest here, show little differentiation on a macro- and microscopic scale and appear as unsorted volcaniclastics with dominating juvenile lapilli and accidental clasts in the range of (sub)millimetres to centimetres in diameter. Decimeter-sized blocks of the crystalline basement occur at certain depths, but are comparatively scarce and inconspicuous, concerning the total thickness of the tuffs. Rock magnetic properties measured on core samples of the lapilli tuffs explain the origin of detected downhole magnetic anomalies performed during the drilling project 2001. Thereby, the juvenile fragments as main carrier of ferrimagnetic minerals (titano-magnetites) specify the rock magnetic character of the volcanic material and account for downhole logging data of the magnetic susceptibility (MS) and the natural remanent magnetisation (NRM). Besides similar remanence acquisition properties throughout the lapilli tuffs, differences in the magnetic stability behaviour are realised for the upper and lower half of the tuffs. Thermal magnetic experiments prove the magnetic differences and the acquisition of (partial) thermal remanent magnetisation (pTRM), respectively, and allow estimations of emplacement temperatures 300 ° C for the lower half of the lapilli tuffs. This study deals with image analytical and geochemical investigations on juvenile fragments as implication for the rock magnetic results and provides insights into the heat and magma source of the Messel maar

An investigation of the mechanical and hydrologic behavior of tuff fractures under saturated conditions

International Nuclear Information System (INIS)

Voss, C.F.; Shotwell, L.R.

1990-04-01

The mechanical and hydrologic behavior of natural fractures in a partially welded tuff rock were investigated. Tuff cores, each containing part of the same natural fracture oriented subparallel to the core axis, were subjected a range of stress and hydraulic gradients while simultaneously monitoring changes in the fracture aperture and volumetric flow rate. The fractures were tested in three configurations: intact, mated, and offset. Fracture deformation was nonlinear over the stress range tested with permanent deformation and hysteresis occurring with each loading cycle. The offset samples had larger permanent deformation and significantly reduced normal stiffness at lower stress levels. The cubic flow law appears to be valid for the relatively undisturbed tuff fractures at the scale tested. The cubic law did not explain the observed hydraulic behavior of the offset fractures. 6 refs., 10 figs., 2 tabs

Antigravity hills are visual illusions.

Science.gov (United States)

Bressan, Paola; Garlaschelli, Luigi; Barracano, Monica

2003-09-01

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.

Research on the calculation method of shale and tuff content: taking tuffaceous reservoirs of X depression in the Hailar–Tamtsag Basin as an example

International Nuclear Information System (INIS)

Liu, Sihui; Huang, Buzhou; Pan, Baozhi; Guo, Yuhang; Fang, Chunhui; Wang, Guiping; Sun, Fengxian; Qiu, Haibo; Jiang, Bici

2015-01-01

Shale content is known in reservoir evaluation as an important parameter in well logging. However, the log response characteristics are simultaneously affected by shale and tuff existing in tuffaceous sandstone reservoirs. Due to the fact that tuff content exerts an influence on the calculation of shale content, the former is equally important as the latter. Owing to the differences in the source and composition between shale and tuff, the calculation of tuff content using the same methods for shale content cannot meet the accuracy requirements of logging evaluation. The present study takes the tuffaceous reservoirs in the X depression of the Hailar–Tamtsag Basin as an example. The differences in the log response characteristics between shale and tuff are theoretically analyzed and verified using core analysis data. The tuff is then divided into fine- and coarse-grained fractions, according to the differences in the distribution of the radioactive elements, uranium, thorium and potassium. Next, a volume model suitable for tuffaceous sandstone reservoirs is established to include a sandstone matrix, shale, fine-grained tuff, coarse-grained tuff and pore. A comparison of three optimization algorithms shows that the particle swarm optimization (PSO) yields better calculation results with small mean errors. The resistivity differences among shale, fine-grained tuff and coarse-grained tuff are considered in the calculation of saturation. The water saturation of tuffaceous reservoirs is computed using the improved Poupon’s equation, which is suitable for tuffaceous sandstone reservoirs with low water salinity. The method is used in well Y, and is shown to have a good application effect. (paper)

Contrasting perspectives on the Lava Creek Tuff eruption, Yellowstone, from new U-Pb and 40Ar/39Ar age determinations

Science.gov (United States)

Wilson, Colin J. N.; Stelten, Mark E.; Lowenstern, Jacob B.

2018-06-01

The youngest major caldera-forming event at Yellowstone was the 630-ka eruption of the Lava Creek Tuff. The tuff as mapped consists of two major ignimbrite packages (members A and B), linked to widespread coeval fall deposits and formation of the Yellowstone Caldera. Subsequent activity included emplacement of numerous rhyolite flows and domes, and development of two structurally resurgent domes (Mallard Lake and Sour Creek) that accommodate strain due to continual uplift/subsidence cycles. Uplifted lithologies previously mapped on and adjacent to Sour Creek dome were thought to include the 2.08-Ma Huckleberry Ridge Tuff, cropping out beneath Lava Creek Tuff members A and B. Mapped outcrops of this Huckleberry Ridge Tuff material were sampled as welded ignimbrite (sample YR345) on Sour Creek dome, and at nearby Bog Creek as welded ignimbrite (YR311) underlain by an indurated lithic lag breccia containing blocks of another welded ignimbrite (YR324). Zircon near-rim U-Pb analyses from these samples yield weighted mean ages of 661 ± 13 ka (YR345: 95% confidence), 655 ± 11 ka (YR311), and 664 ± 15 ka (YR324) (combined weighted mean of 658.8 ± 6.6 ka). We also studied two samples of ignimbrite previously mapped as Huckleberry Ridge Tuff on the northeastern perimeter of the Yellowstone Caldera, 12 km ENE of Sour Creek dome. Sanidines from these samples yield 40Ar/39Ar age estimates of 634.5 ± 6.8 ka (8YC-358) and 630.9 ± 4.1 ka (8YC-359). These age data show that all these units represent previously unrecognized parts of the Lava Creek Tuff and do not have any relationship to the Huckleberry Ridge Tuff. Our observations and data imply that the Lava Creek eruption was more complex than is currently assumed, incorporating two tuff units additional to those currently mapped, and which themselves are separated by a time break sufficient for cooling and some reworking. The presence of a lag breccia suggests that a source vent lay nearby (Caldera boundary in this area

Contrasting perspectives on the Lava Creek Tuff eruption, Yellowstone, from new U–Pb and 40Ar/39Ar age determinations

Science.gov (United States)

Wilson, Colin J. N.; Stelten, Mark; Lowenstern, Jacob B.

2018-01-01

The youngest major caldera-forming event at Yellowstone was the ~ 630-ka eruption of the Lava Creek Tuff. The tuff as mapped consists of two major ignimbrite packages (members A and B), linked to widespread coeval fall deposits and formation of the Yellowstone Caldera. Subsequent activity included emplacement of numerous rhyolite flows and domes, and development of two structurally resurgent domes (Mallard Lake and Sour Creek) that accommodate strain due to continual uplift/subsidence cycles. Uplifted lithologies previously mapped on and adjacent to Sour Creek dome were thought to include the ~ 2.08-Ma Huckleberry Ridge Tuff, cropping out beneath Lava Creek Tuff members A and B. Mapped outcrops of this Huckleberry Ridge Tuff material were sampled as welded ignimbrite (sample YR345) on Sour Creek dome, and at nearby Bog Creek as welded ignimbrite (YR311) underlain by an indurated lithic lag breccia containing blocks of another welded ignimbrite (YR324). Zircon near-rim U–Pb analyses from these samples yield weighted mean ages of 661 ± 13 ka (YR345: 95% confidence), 655 ± 11 ka (YR311), and 664 ± 15 ka (YR324) (combined weighted mean of 658.8 ± 6.6 ka). We also studied two samples of ignimbrite previously mapped as Huckleberry Ridge Tuff on the northeastern perimeter of the Yellowstone Caldera, ~ 12 km ENE of Sour Creek dome. Sanidines from these samples yield 40Ar/39Ar age estimates of 634.5 ± 6.8 ka (8YC-358) and 630.9 ± 4.1 ka (8YC-359). These age data show that all these units represent previously unrecognized parts of the Lava Creek Tuff and do not have any relationship to the Huckleberry Ridge Tuff. Our observations and data imply that the Lava Creek eruption was more complex than is currently assumed, incorporating two tuff units additional to those currently mapped, and which themselves are separated by a time break sufficient for cooling and some reworking. The presence of a lag breccia suggests that a source

An astronomical age for the Bishop Tuff and concordance with radioisotopic dates

DEFF Research Database (Denmark)

Rivera, Tiffany; Zeeden, Christian; Storey, Michael

2014-01-01

The Bishop Tuff forms a key stratigraphic horizon for synchronization of Quaternary sedimentary records in North America. The unit stratigraphically overlies the Matuyama-Brunhes geomagnetic polarity reversal by several thousand years; high-precision dating of this tuff may be valuable for regional...... and global correlation of records. The Quaternary time scale is anchored by 40Ar/39Ar ages on lava flows and ash layers where available, with stage boundaries and geomagnetic reversals including astronomically tuned records. However, astronomical dating has not yet validated the high-precision 238U/206Pb...... ages, including new single crystal 40Ar/39Ar sanidine fusion analyses presented here, which demonstrates that concordance through multiple dating techniques is achievable within the Quaternary...

Criticality characteristics of mixtures of plutonium, silicon dioxide, Nevada tuff, and water

International Nuclear Information System (INIS)

Sanchez, R.G.; Myers, W.; Stratton, W.

1996-01-01

The major objective of this study has been to examine the possibility of a nuclear explosion should 50 to 100 kg of plutonium be mixed with SiO 2 , vitrified, placed within a heavy steel container, and buried in the material known as Nevada tuff. To accomplish this objective, the authors have created a survey of critical states or configurations of mixtures of plutonium, SiO 2 , tuff, and water and examined these data to determine those configurations that might be unstable or autocatalytic. They have identified regions of criticality instability with the possibility of autocatalytic power behavior. Autocatalytic behavior is possible but improbable, for a very limited range of wet systems

Repository site data report for unsaturated tuff, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Tien, P.L.; Updegraff, C.D.; Siegel, M.D.; Wahi, K.K.; Guzowski, R.V.

1985-11-01

The US Department of Energy is currently considering the thick sequences of unsaturated, fractured tuff at Yucca Mountain, on the southwestern boundary of the Nevada Test Site, as a possible candidate host rock for a nuclear-waste repository. Yucca Mountain is in one of the most arid areas in the United States. The site is within the south-central part of the Great Basin section of the Basin and Range physiographic province and is located near a number of silicic calderas of Tertiary age. Although localized zones of seismic activity are common throughout the province, and faults are present at Yucca Mountain, the site itself is basically aseismic. No data are available on the composition of ground water in the unsaturated zone at Yucca Mountain. It has been suggested that the composition is bounded by the compositions of water from wells USW-H3, UE25p-1, J-13, and snow or rain. There are relatively few data available from Yucca Mountain on the moisture content and saturation, hydraulic conductivity, and characteristic curves of the unsaturated zone. The available literature on thermomechanical properties of tuff does not always distinguish between data from the saturated zone and data from the unsaturated zone. Geochemical, hydrologic, and thermomechanical data available on the unsaturated tuffs of Yucca Mountain are tabulated in this report. Where the data are very sparse, they have been supplemented by data from the saturated zone or from areas other than Yucca Mountain. 316 refs., 58 figs., 37 tabs

Repository site data report for unsaturated tuff, Yucca Mountain, Nevada

Energy Technology Data Exchange (ETDEWEB)

Tien, P.L.; Updegraff, C.D.; Siegel, M.D.; Wahi, K.K.; Guzowski, R.V.

1985-11-01

The US Department of Energy is currently considering the thick sequences of unsaturated, fractured tuff at Yucca Mountain, on the southwestern boundary of the Nevada Test Site, as a possible candidate host rock for a nuclear-waste repository. Yucca Mountain is in one of the most arid areas in the United States. The site is within the south-central part of the Great Basin section of the Basin and Range physiographic province and is located near a number of silicic calderas of Tertiary age. Although localized zones of seismic activity are common throughout the province, and faults are present at Yucca Mountain, the site itself is basically aseismic. No data are available on the composition of ground water in the unsaturated zone at Yucca Mountain. It has been suggested that the composition is bounded by the compositions of water from wells USW-H3, UE25p-1, J-13, and snow or rain. There are relatively few data available from Yucca Mountain on the moisture content and saturation, hydraulic conductivity, and characteristic curves of the unsaturated zone. The available literature on thermomechanical properties of tuff does not always distinguish between data from the saturated zone and data from the unsaturated zone. Geochemical, hydrologic, and thermomechanical data available on the unsaturated tuffs of Yucca Mountain are tabulated in this report. Where the data are very sparse, they have been supplemented by data from the saturated zone or from areas other than Yucca Mountain. 316 refs., 58 figs., 37 tabs.

Analysis of aquifer tests conducted in borehole USW G-2, 1996, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

O'Brien, G.M.

1998-01-01

Borehole USW G-2 is located north of Yucca Mountain in a large-hydraulic-gradient area. Two single-borehole aquifer tests were conducted in the borehole during 1996. A 54.9-hour pumping period was conducted February 6--8, 1996, and a 408-hour pumping period was conducted April 8--25, 1996. The purpose of testing was to obtain estimates of the aquifer-system transmissivity and to determine if perched water was affecting the observed water level in borehole USW G-2. This report presents and analyzes data collected between February 6 and December 17, 1996. Analysis of the aquifer-test data indicated that fracture flow, dual-porosity flow, and boundary-affected flow conditions were observed in the drawdown and recovery data. Transmissivity estimates ranged from 2.3 to 12 meters squared per day. The most representative transmissivity estimate for the interval tested is the early-time mean transmissivity of 9.4 meters squared per day. The Calico Hills Formation was the primary formation tested, but the top 3 meters of the nonpumping water column was within the overlying Topopah Spring Tuff. Persistent residual drawdown following pumping more than 6 million liters of water during aquifer testing may indicate that the bore-hole intersected a perched water body. After 236 days of recovery, residual drawdown was 0.5 meter. The quantitative effect of the perched water on the observed water level in borehole USW G-2, however, cannot be determined with the available data

Bond strength of cementitious borehole plugs in welded tuff

International Nuclear Information System (INIS)

Akgun, H.; Daemen, J.J.K.

1991-02-01

Axial loads on plugs or seals in an underground repository due to gas, water pressures and temperature changes induced subsequent to waste and plug emplacement lead to shear stresses at the plug/rock contact. Therefore, the bond between the plug and rock is a critical element for the design and effectiveness of plugs in boreholes, shafts or tunnels. This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young's modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. The main conclusion is a strong recommendation to design friction plugs in shafts, drifts, tunnels or boreholes with a minimum length to diameter ratio of four. Such a geometrical design will reduce tensile stresses in the plug and in the host rock to a level which should minimize the risk of long-term deterioration caused by excessive tensile stresses. Push-out tests have been used to determine the bond strength by applying an axial load to cement plugs emplaced in boreholes in welded tuff cylinders. A total of 130 push-out tests have been performed as a function of borehole size, plug length, temperature, and degree of saturation of the host tuff. The use of four different borehole radii enables evaluation of size effects. 119 refs., 42 figs., 20 tabs

Radionuclide sorption in Yucca Mountain tuffs with J-13 well water: Neptunium, uranium, and plutonium. Yucca Mountain site characterization program milestone 3338

International Nuclear Information System (INIS)

Triay, I.R.; Cotter, C.R.; Kraus, S.M.; Huddleston, M.H.

1996-08-01

We studied the retardation of actinides (neptunium, uranium, and plutonium) by sorption as a function of radionuclide concentration in water from Well J-13 and of tuffs from Yucca Mountain. Three major tuff types were examined: devitrified, vitric, and zeolitic. To identify the sorbing minerals in the tuffs, we conducted batch sorption experiments with pure mineral separates. These experiments were performed with water from Well J-13 (a sodium bicarbonate groundwater) under oxidizing conditions in the pH range from 7 to 8.5. The results indicate that all actinides studied sorb strongly to synthetic hematite and also that Np(V) and U(VI) do not sorb appreciably to devitrified or vitric tuffs, albite, or quartz. The sorption of neptunium onto clinoptilolite-rich tuffs and pure clinoptilolite can be fitted with a sorption distribution coefficient in the concentration range from 1 X 10 -7 to 3 X 10 -5 M. The sorption of uranium onto clinoptilolite-rich tuffs and pure clinoptilolite is not linear in the concentration range from 8 X 10 -8 to 1 X 10 -4 M, and it can be fitted with nonlinear isotherm models (such as the Langmuir or the Freundlich Isotherms). The sorption of neptunium and uranium onto clinoptilolite in J-13 well water increases with decreasing pH in the range from 7 to 8.5. The sorption of plutonium (initially in the Pu(V) oxidation state) onto tuffs and pure mineral separates in J-13 well water at pH 7 is significant. Plutonium sorption decreases as a function of tuff type in the order: zeolitic > vitric > devitrified; and as a function of mineralogy in the order: hematite > clinoptilolite > albite > quartz

Consideration of Nuclear Criticality When Directly Disposing Highly Enriched Spent Nuclear Fuel in Unsaturated Tuff - I: Nuclear Criticality Constraints

International Nuclear Information System (INIS)

Rechard, Rob P.; Sanchez, Lawrence C.; Trellue, Holly R.

2003-01-01

This paper presents the mass, concentration, and volume required for a critical event to occur in homogeneous mixtures of fissile material and various other geologic materials. The fissile material considered is primarily highly enriched uranium spent fuel; however, 239 Pu is considered in some cases. The non-fissile materials examined are those found in the proposed repository area at Yucca Mountain, Nevada: volcanic tuff, iron rust, concrete, and naturally occurring water. For 235 U, the minimum critical solid concentration for tuff was 5 kg/m 3 (similar to sandstone), and in goethite, 45 kg/m 3 . The critical mass of uranium was sensitive to a number of factors, such as moisture content and fissile enrichment, but had a minimum, assuming almost 100% saturation and >20% enrichment, of 18 kg in tuff as Soddyite (or 9.5 kg as UO 2 ) and 7 kg in goethite. For 239 Pu, the minimum critical solid concentration for tuff was 3 kg/m 3 (similar to sandstone); in goethite, 20 kg/m 3 . The critical mass of plutonium was also sensitive to a number of factors, but had a minimum, assuming 100% saturation and 80-90% enrichment, of 5 kg in tuff and 6 kg in goethite

Effects of tuff waste package components on release from 76-68 simulated waste glass: Final report

International Nuclear Information System (INIS)

McVay, G.L.; Robinson, G.R.

1984-04-01

An experimental matrix has been conducted that will allow evaluation of the effects of waste package constituents on the waste form release behavior in a tuff repository environment. Tuff rock and groundwater were used along with 304L, 316, and 1020M ferrous metals to evaluate release from uranium-doped MCC 76-68 simulated waste glass. One of the major findings was that in the absence of 1020M mild steel, tuff rock powder dominates the system. However, when 1020M mild steel is present, it appears to dominate the system. The rock-dominated system results in suppressed glass-water reaction and leaching while the 1020M-dominated system results in enhanced leaching - but the metal effectively scavenges uranium from solution. The 300-series stainless steels play no significant role in affecting glass leaching characteristics. 6 refs., 28 figs., 5 tabs

Zircaloy cladding corrosion degradation in a Tuff repository: initial experimental plan

International Nuclear Information System (INIS)

Smith, H.D.

1984-07-01

The projected environmental history of a Tuff repository sited in an unsaturated hydrologic setting is evaluated to identify the potentially most severe corrosion conditions for Zircaloy spent fuel cladding. Three distinct corrosion periods are identified over the projected history. In two of those, liquid water may be present which is believed to produce the most severe corrosive environment for Zircaloy spent fuel cladding. In the time interval 100 to 1000 years after emplacement in the repository, the most severe condition is exposure to 170 0 C water at about 100 psi in an unbreached canister. This condition will be reproduced experimentally in an autoclave. For times after 1000 years, the most severe condition is exposure to 90 0 C water that is equilibrated with the tuff and invades breached canisters. This condition will be reproduced with a water bath system

Uniaxial compression test series on Bullfrog Tuff

International Nuclear Information System (INIS)

Price, R.H.; Jones, A.K.; Nimick, K.G.

1982-04-01

Nineteen uniaxial compressive experiments were performed on samples of the Bullfrog Member of the Crater Flat Tuff, obtained from drillhole USW-G1 at Yucca Mountain on the Nevada Test Site. The water saturated samples were deformed at a nominal strain rate of 10 -5 sec -1 , atmospheric pressure and room temperature. Resultant unconfined compressive strengths, axial strains to failure, Young's moduli and Poisson's ratios ranged from 4.63 to 153. MPa, .0028 to .0058, 2.03 to 28.9 GPa and .08 to .16, respectively

Determination of Heat Capacity of Yucca Mountain Stratigraphic Layers

International Nuclear Information System (INIS)

T. Hadgu; C. Lum; J.E. Bean

2006-01-01

The heat generated from the radioactive waste to be placed in the proposed geologic repository at Yucca Mountain, Nevada, will affect the thermal-hydrology of the Yucca Mountain stratigraphic layers. In order to assess the effect of the movement of repository heat into the fractured rocks accurate determination of thermodynamic and hydraulic properties is important. Heat capacity is one of the properties that are required to evaluate energy storage in the fractured rock. Rock-grain heat capacity, the subject of this study, is the heat capacity of the solid part of the rock. Yucca Mountain consists of alternating lithostratigraphic units of welded and non-welded ash-flow tuff, mainly rhyolitic in composition and displaying varying degrees of vitrification and alteration. A number of methods exist that can be used to evaluate heat capacity of the stratigraphic layers that consist of different compositions. In this study, the mineral summation method has been used to quantify the heat capacity of the stratigraphic layers based on Kopp's rule. The mineral summation method is an addition of the weighted heat capacity of each mineral found in a specific layer. For this study the weighting was done based on the mass percentage of each mineral in the layer. The method utilized a mineralogic map of the rocks at the Yucca Mountain repository site. The Calico Hills formation and adjacent bedded tuff layers display a bimodal mineral distribution of vitric and zeolitic zones with differing mineralogies. Based on this bimodal distribution in zeolite abundance, the boundary between the vitric and zeolitic zones was selected to be 15% zeolitic abundance. Thus, based on the zeolite abundance, subdivisions have been introduced to these layers into ''vitric'' and ''zeolitic'' zones. Heat capacity values have been calculated for these layers both as ''layer average'' and ''zone average''. The heat capacity determination method presented in this report did not account for spatial

Some geochemical considerations for a potential repository site in tuff at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Erdal, B.R.; Bish, D.L.; Crowe, B.M.; Daniels, W.R.; Ogard, A.E.; Rundberg, R.S.; Vaniman, D.T.; Wolfsberg, K.

1982-01-01

The Nevada Nuclear Waste Storage Investigations, which is evaluating potential locations for a high-level waste repository at the Nevada Test Site and environs, is currently focusing its investigations on tuff, principally in Yucca Mountain, as a host rock. This paper discusses some of the geochemical investigations. Particular emphasis is placed on definition of some basic elements and necessary technical approaches for the geochemistry data acquisition and modeling program. Some site-specific tuff geochemical information that is important for site selection and repository performance will be identified and the current status of knowledge will then be discussed

Geohydrology of Bandelier Tuff

International Nuclear Information System (INIS)

Abeele, M.V.; Wheeler, M.L.; Burton, B.W.

1981-10-01

The Los Alamos National Laboratory has been disposing of radioactive wastes since 1944. Environmental studies and monitoring for radioactive contamination started concurrently. In this report, only two mechanisms and rates by which the radionuclides can enter the environment are studied in detail: subsurface transport of radionuclides by migrating water, and diffusion of tritiated water (HTO) in the vapor phase. The report also includes a section concerning the influence of moisture on shear strength and possible resulting subsidences occurring in the pit overburdens. Because subsurface transport of radionuclides is influenced by the hydraulic conductivity and this in turn is regulated by the moisture content of any given material, a study was also undertaken involving precipitation, the most important climatic element influencing the geohydrology of any given area. Further work is in progress to correlate HTO emanation to atmospheric and pedological properties, especially including thermal characteristics of the tuff

Creep in Topopah Spring Member welded tuff. Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Martin, R.J. III; Boyd, P.J.; Noel, J.S. [New England Research, Inc., White River Junction, VT (United States); Price, R.H. [Sandia National Labs., Albuquerque, NM (United States)

1995-06-01

A laboratory investigation has been carried out to determine the effects of elevated temperature and stress on the creep deformation of welded tuffs recovered from Busted Butte in the vicinity of Yucca Mountain, Nevada. Water saturated specimens of tuff from thermal/mechanical unit TSw2 were tested in creep at a confining pressure of 5.0 MPa, a pore pressure of 4.5 MPa, and temperatures of 25 and 250 C. At each stress level the load was held constant for a minimum of 2.5 {times} 10{sup 5} seconds and for as long as 1.8 {times} 10{sup 6} seconds. One specimen was tested at a single stress of 80 MPa and a temperature of 250 C. The sample failed after a short time. Subsequent experiments were initiated with an initial differential stress of 50 or 60 MPa; the stress was then increased in 10 MPa increments until failure. The data showed that creep deformation occurred in the form of time-dependent axial and radial strains, particularly beyond 90% of the unconfined, quasi-static fracture strength. There was little dilatancy associated with the deformation of the welded tuff at stresses below 90% of the fracture strength. Insufficient data have been collected in this preliminary study to determine the relationship between temperature, stress, creep deformation to failure, and total failure time at a fixed creep stress.

Creep in Topopah Spring Member welded tuff. Yucca Mountain Site Characterization Project

International Nuclear Information System (INIS)

Martin, R.J. III; Boyd, P.J.; Noel, J.S.; Price, R.H.

1995-06-01

A laboratory investigation has been carried out to determine the effects of elevated temperature and stress on the creep deformation of welded tuffs recovered from Busted Butte in the vicinity of Yucca Mountain, Nevada. Water saturated specimens of tuff from thermal/mechanical unit TSw2 were tested in creep at a confining pressure of 5.0 MPa, a pore pressure of 4.5 MPa, and temperatures of 25 and 250 C. At each stress level the load was held constant for a minimum of 2.5 x 10 5 seconds and for as long as 1.8 x 10 6 seconds. One specimen was tested at a single stress of 80 MPa and a temperature of 250 C. The sample failed after a short time. Subsequent experiments were initiated with an initial differential stress of 50 or 60 MPa; the stress was then increased in 10 MPa increments until failure. The data showed that creep deformation occurred in the form of time-dependent axial and radial strains, particularly beyond 90% of the unconfined, quasi-static fracture strength. There was little dilatancy associated with the deformation of the welded tuff at stresses below 90% of the fracture strength. Insufficient data have been collected in this preliminary study to determine the relationship between temperature, stress, creep deformation to failure, and total failure time at a fixed creep stress

Thermal conductivity, bulk properties, and thermal stratigraphy of silicic tuffs from the upper portion of hole USW-G1, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Lappin, A.R.; VanBuskirk, R.G.; Enniss, D.O.; Buters, S.W.; Prater, F.M.; Muller, C.B.; Bergosh, J.L.

1982-03-01

Thermal-conductivity and bulk-property measurements were made on welded and nonwelded silicic tuffs from the upper portion of Hole USW-G1, located near the southwestern margin of the Nevada Test Site. Bulk-property measurements were made by standard techniques. Thermal conductivities were measured at temperatures as high as 280 0 C, confining pressures to 10 MPa, and pore pressures to 1.5 MPa. Extrapolation of measured saturated conductivities to zero porosity suggests that matrix conductivity of both zeolitized and devitrified tuffs is independent of stratigraphic position, depth, and probably location. This fact allows development of a thermal-conductivity stratigraphy for the upper portion of Hole G1. Estimates of saturated conductivities of zeolitized nonwelded tuffs and devitrified tuffs below the water table appear most reliable. Estimated conductivities of saturated densely welded devitrified tuffs above the water table are less reliable, due to both internal complexity and limited data presently available. Estimation of conductivity of dewatered tuffs requires use of different air thermal conductivities in devitrified and zeolitized samples. Estimated effects of in-situ fracturing generally appear negligible

G-Tunnel Welded Tuff Mining experiment evaluations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Bellman, R.A. Jr.; Mann, K.L.; Zerga, D.P.; Fowler, M.; Johnson, J.R.

1988-12-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a mine-by in welded tuff so that predictive-type information could be obtained regarding the response of the rock to a drill and blast excavation process, where smooth blasting techniques were used. This report describes the results of the mining processes and presents and discusses the rock mass responses to the mining and ground support activities. 37 refs., 20 figs., 7 tabs

The Tala Tuff, La Primavera caldera Mexico. Pre-eruptive conditions and magma processes before eruption

Science.gov (United States)

Sosa-Ceballos, G.

2015-12-01

La Primavera caldera, Jalisco Mexico, is a Pleistocenic volcanic structure formed by dome complexes and multiple pyroclastic flows and fall deposits. It is located at the intersection of the Chapala, Colima, and Tepic grabens in western Mexico. The first volcanic activity associated to La Primavera started ~0.1 Ma with the emission of pre-caldera lavas. The caldera collapse occurred 95 ka and is associated to the eruption of ~20 km3of pumice flows known as the Tala tuff (Mahood 1980). The border of the caldera was replaced by a series of domes dated in 75-30 ky, which partially filled the inner depression of the caldera with pyroclastic flows and falls. For more than a decade the Federal Commission of Electricity in Mexico (CFE) has prospected and evaluated the geothermal potential of the Cerritos Colorados project at La Primavera caldera. In order to better understand the plumbing system that tapped the Tala tuff and to investigate its relation with the potential geothermal field at La Primavera we performed a series of hydrothermal experiments and studied melt inclusions hosted in quartz phenocrysts by Fourier Infra red stectroscopy (FTIR). Although some post caldera products at La Primavera contain fayalite and quartz (suggesting QFM conditions) the Tala tuff does not contain fayalite and we ran experiments under NNO conditions. The absence of titanomagnetite does not allowed us to calculate pre-eruptive temperature. However, the stability of quartz and plagioclase, which are natural phases, suggest that temperature should be less than 750 °C at a pressure of 200 MPa. The analyses of H2O and CO2 dissolved in melt inclusions yielded concentrations of 2-5 wt.% and 50-100 ppm respectively. This data confirm that the pre-eruptive pressure of the Tala tuff is ~200 MPa and in addition to major elements compositions suggest that the Tala tuff is either, compositionally zoned or mixed with other magma just prior to eruption.

Pore-water extraction from unsaturated tuff by triaxial and one-dimensional compression methods, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

Mower, T.E.; Higgins, J.D.; Yang, In C.; Peters, C.A.

1994-01-01

The hydrologic system in the unsaturated tuff at Yucca Mountain, Nevada, is being evaluated for the US Department of Energy by the Yucca Mountain Project Branch of the US Geological Survey as a potential site for a high-level radioactive-waste repository. Part of this investigation includes a hydrochemical study that is being made to assess characteristics of the hydrologic system such as: traveltime, direction of flow, recharge and source relations, and types and magnitudes of chemical reactions in the unsaturated tuff. In addition, this hydrochemical information will be used in the study of the dispersive and corrosive effects of unsaturated-zone water on the radioactive-waste storage canisters. This report describes the design and validation of laboratory experimental procedures for extracting representative samples of uncontaminated pore water from welded and nonwelded, unsaturated tuffs from the Nevada Test Site

Microautoradiography in studies of Pu(V) sorption by trace and fracture minerals in tuff

International Nuclear Information System (INIS)

Vaniman, D.; Furlano, A.; Chipera, S.; Thompson, J.; Triay, I.

1996-01-01

Microautoradiography was used to evaluate the mineralogic basis of Pu(V) retention by tuffs from Yucca Mountain, Nevada. Altered orthopyroxenes and oxide minerals are associated with high Pu retention but are limited to specific stratigraphic horizons. A weaker but more general association of Pu with smectite occurs in most samples. Thin-sections that cross fractures allow comparative studies of Pu retention by fracture-lining versus matrix minerals. Using Ag metal in emulsions as a measure of underlying Pu concentration, electron-microprobe analysis can quantify Pu retention along fracture walls and provide mineral/mineral Pu retention factors. For smectite-lined microfractures in zeolitized tuff, the smectite/clinoptilolite Pu retention factor is >80

Further description of the petrology of the Topopah Spring member of the paintbrush tuff in drill holes UE25A-1 and USW-G1 and of the lithic-rich tuff in USW-G1, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Carroll, P.I.; Caporuscio, F.A.; Bish, D.L.

1981-11-01

The Topopah Spring Member of the Paintbrush Tuff and the Lithic-rich tuff and two Tertiary volcanic units that occur in cores from drill holes UE25a-1 and USW-G1 at Yucca Mountain, Nevada. Recently they have been suggested as possibly suitable for the permanent storage of high-level radioactive waste. Earlier petrologic characterization of these units is augmented here. The Topopah Spring Member (approximately 350 m thick) has two compound cooling units. The upper, thinner unit is densely welded to vitrophyric. The lower unit ranges from nonwelded to vitrophyric, and its nonwelded base is extensively zeolitized to clinoptilolite and mordenite. Heulandite occurs as fracture fill in the overlying vitrophyric part, but zeolites are absent above that vitrophyre. Here primary devitrification plus vapor-phase crystallization dominate the mineralogy. Vapor-phase effects are especially prominent between the two vitrophyres in both cores and include numerous large lithophysal cavities throughout most of this moderately to densely welded tuff. The Lithic-rich tuff extends from 1203 to 1506 m in the USW-G1 drill core. It is nonwelded to partly welded but is well indurated due to pervasive intergrowths of authigenic minerals. These phases are analcime, albite, alkali feldspar, sericite, chlorite and quartz. The transition from analcime to secondary albite corresponds to Iijima's zeolite Zone IV boundary, and this boundary appears in USW-G1 at 1326 m. However, analcime remains as a prominent phase through most of the Lithic-rich tuff. Further work is necessary to assess the suitability of either of these horizons for a waste repository. In the Topopah Spring Member, both mechanical and hydrologic properties of thick lithophysal zone must be studied, as well as the complete sequence of fracture fill. For both units, zeolite and clay mineral stabilities need to be investigated

Decay of Rhenish Tuffs in Dutch Monuments. Part 2 : Laboratory Experiments as a Basis for the Choice of Restoration Stone

NARCIS (Netherlands)

Van Hees, R.P.J.; Brendle, S.; Nijland, T.G.; De Haas, G.J.L.M.; Tolboom, H.J.

2003-01-01

Rhenish tuffs (Eifel, Germany), have been used as building material in the Netherlands since Roman times. They were the most important natural building stone in the Netherlands in early medieval times. In addition, tuff was used as raw material for production of trass, that served as a pozzolanic

Decay of Rhenish Tuff in Dutch monuments. Part 2 : Laboratory experiments as a basis for the choice of restoration stone

NARCIS (Netherlands)

Hees, R.P.J. van; Brendle, S.; Nijland, T.G.; Haas, G.J.L.M. de; Tolboom, H.J.

2003-01-01

Rhenish tuffs (Eifel, Getmany), have been used as building material in the Netherlands since Roman times. They were the most important natural building stone in the Netherlands in early medieval times. In addition, tuff was used as raw material for production of trass, that served as a pozzolanic

Geologic map of the northern White Hills, Mohave County, Arizona

Science.gov (United States)

Howard, Keith A.; Priest, Susan S.; Lundstrom, Scott C.; Block, Debra L.

2017-07-10

IntroductionThe northern White Hills map area lies within the Kingman Uplift, a regional structural high in which Tertiary rocks lie directly on Proterozoic rocks as a result of Cretaceous orogenic uplift and erosional stripping of Paleozoic and Mesozoic strata. The Miocene Salt Spring Fault forms the major structural boundary in the map area. This low-angle normal fault separates a footwall (lower plate) of Proterozoic gneisses on the east and south from a hanging wall (upper plate) of faulted middle Miocene volcanic and sedimentary rocks and their Proterozoic substrate. The fault is part of the South Virgin–White Hills Detachment Fault, which records significant tectonic extension that decreases from north to south. Along most of its trace, the Salt Spring Fault dips gently westward, but it also has north-dipping segments along salients. A dissected, domelike landscape on the eroded footwall, which contains antiformal salients and synformal reentrants, extends through the map area from Salt Spring Bay southward to the Golden Rule Peak area. The “Lost Basin Range” represents an upthrown block of the footwall, raised on the steeper Lost Basin Range Fault.The Salt Spring Fault, as well as the normal faults that segment its hanging wall, deform rocks that are about 16 to 10 Ma, and younger deposits overlie the faults. Rhyodacitic welded tuff about 15 Ma underlies a succession of geochemically intermediate to progressively more mafic lavas (including alkali basalt) that range from about 14.7 to 8 Ma, interfingered with sedimentary rocks and breccias in the western part of the map area. Upper Miocene strata record further filling of the extension-formed continental basins. Basins that are still present in the modern landscape reflect the youngest stages of extensional-basin formation, expressed as the downfaulted Detrital Valley and Hualapai Wash basins in the western and eastern parts of the map area, respectively, as well as the north-centrally located

Geologic Map of the Bodie Hills Volcanic Field, California and Nevada: Anatomy of Miocene Cascade Arc Magmatism in the Western Great Basin

Science.gov (United States)

John, D. A.; du Bray, E. A.; Blakely, R. J.; Box, S.; Fleck, R. J.; Vikre, P. G.; Rytuba, J. J.; Moring, B. C.

2011-12-01

The Bodie Hills Volcanic Field (BHVF) is a >700 km2, long-lived (~9 Ma) but episodic, Miocene eruptive center in the southern part of the ancestral Cascade magmatic arc. A 1:50,000-scale geologic map based on extensive new mapping, combined with 40Ar/39Ar dates, geochemical data, and detailed gravity and aeromagnetic surveys, defines late Miocene magmatic and hydrothermal evolution of the BHVF and contrasts the subduction-related BHVF with the overlying, post-subduction, bimodal Plio-Pleistocene Aurora Volcanic Field (AVF). Important features of the BHVF include: Eruptions occurred during 3 major eruptive stages: dominantly trachyandesite stratovolcanoes (~14.7 to 12.9 Ma), mixed silicic trachyandesite, dacite, and rhyolite (~11.3 to 9.6 Ma), and dominantly silicic trachyandesite to dacite domes (~9.2 to 8.0 Ma). Small rhyolite domes were emplaced at ~6 Ma. Trachyandesitic stratovolcanoes with extensive debris flow aprons form the outer part of BHVF, whereas silicic trachyandesite to rhyolite domes are more centrally located. Geophysical data suggest that many BHVF volcanoes have shallow plutonic roots that extend to depths ≥1-2 km below the surface, and much of the Bodie Hills may be underlain by low density plutons presumably related to BHVF volcanism. BHVF rocks contain ~50 to 78% SiO2 (though few rocks have Bodie Hills at ~10 Ma, but the composition and eruptive style of volcanism continued unchanged for 2 Ma. However, kinematic data for veins and faults in mining districts suggest a change in the stress field from transtensional to extensional approximately coincident with cessation of subduction. The Bodie Hills are flanked to the east, north, and west by sedimentary basins that began to form in the late Miocene (locally >11 Ma). Fine to coarse sedimentary deposits within the BHVF include stream deposits in channels that cut across the hills and were partly filled by ~9.4 Ma Eureka Valley Tuff erupted 20 km to the northwest. Shallow dips and preservation of

Fracture-lining minerals in the lower Topopah Spring Tuff at Yucca Mountain

International Nuclear Information System (INIS)

Carlos, B.A.; Bish, D.L.; Chipera, S.J.

1991-01-01

Fracture-lining minerals in the lower Topopah Spring Member of the Paintbrush Tuff at Yucca Mountain, Nevada, are being examined to characterize potential flow paths within and away from the candidate repository horizon. Fracture coatings within this interval can be divided into five categories based on rock matrix and type of fracture. Fracture coatings in the densely welded tuff above the basal vitrophyre, near the candidate repository horizon, include (1) those related to lithophysal cavities; (2) mordenite and manganese oxides on nearly planar fractures; (3) later fracture coatings consisting of zeolites, smectite, and calcite. Fracture-coating minerals in the vitrophyre are fine-grained and consist of smectite and a variety of zeolites. The non- to partially-welded vitric and/or zeolitic stuff below the vitrophyre contains fractures mostly lined by cristobalite and clinoptilolite. 13 refs., 2 figs., 1 tab

Thermal analyses for a nuclear-waste repository in tuff using USW-G1 borehole data

International Nuclear Information System (INIS)

Johnson, R.L.

1982-10-01

Thermal calculations using properties of tuffs obtained from the USW-G1 borehole, located near the SW margin of the Nevada Test Site (NTS), have been completed for a nuclear waste repository sited in welded tuff below the water table. The analyses considered two wasteforms, high level waste and spent fuel, emplaced at two different, gross thermal loadings, 50 and 75 kW/Acre (20.24 and 30.36 kW/ha). Calculations were made assuming that no boiling of the groundwater occurs; i.e., that the hydrostatic head potential was reestablished soon after waste emplacement. 23 figures, 2 tables

Mineralogy, origin and commercial value of the zeolite-rich tuffs in the Petrota-Pentalofos area, Evros County, Greece

Directory of Open Access Journals (Sweden)

Walsh, J. N.

1998-04-01

Full Text Available The zeolite-rich tuffs of the Petrota-Pentalofos area were deposited in the Arrestees Basin during the Eocene. They are up to 100 m thick and extend more than 15 Km in a long axis. Most of the outcrops consist of frequent alternations of very fine grained tuff with pumice and lapel tuffs, the latter containing detrital fragments of the Mesozoic substrate of the basin. X-ray Diffraction, Scanning Electron Microscopy and light microscopy analysis on quarry and borehole samples has shown that the tuffs are composed mainly of clinoptilolite and minor cristobalite, with a small proportion of detrital constituents (quartz, mica-schist and pyrogenic crystals (feldspars, quartz, biotite. Minor amounts of mordenite randomly occur in some of the northern outcrops, closer to the occurrences of lava. ICP-AES chemical analysis of the tuffs gives evidence that the original magmas were of quartz-latite composition. The tuffs rest on pre-Cenozoic metamorphic basement and pass gradationally upwards into sandstone and limestone. Evidence is given for deposition of the tuffs in a supra to infra-littoral environment. The zeolitic tuffs originated as epiclastic volcanic sediments, transported by water from the source of the eruption. The transformation of the volcanic glass of the tuffs to zeolite and cristobalite has taken place by meteoric waters in an open hydrological system existed during the Tertiary. The zeolitic rocks are currently being exploited as an animal feed supplement.Las tobas ricas en cebollitas del área de Petrota-Pentalofos se depositaron en la cuenca de Orejitas durante el Doceno. Alcanzan 100 m de potencia y superan los 15 km de extensión longitudinal. La mayoría de los afloramientos consisten en alternancias de toba de grano muy fino y toba de pómez y lapilli con fragmentos detritos del sustrato Mesozoico de la cuenca. Análisis por difamación de rayos X, microscopía electrónica de barrido y microscopía óptica en muestras de mano y de

Update report on fracture flow in saturated tuff: Dynamic transport task for the Nevada Nuclear Waste Investigations

International Nuclear Information System (INIS)

Janecky, D.R.; Rundberg, R.S.; Ott, M.; Mitchell, A.

1990-11-01

This report summarizes the results of continuing experiments on the behavior of tracers during fracture flow in saturated, welded tuff. These experiments were completed during the past year as part of the Dynamic Transport Task of geochemical investigations for the Yucca Mountain Project sponsored by the US Department of Energy. These experiments are designed to investigate the effects of fluid movement in fractures when coupled with matrix diffusion and sorption but isolated from the effects of capillary suction and two-phase flow characteristic of unsaturated conditions. The experiments reported here are continuations of experimental efforts reported previously. The behavior of three tracers [HTO (tritiated water), TcO 4 - (pertechnetate), and sulforhodamine B dye] have been investigated during flow through a saturated column of densely welded tuff from the Topopah Spring Member of the Paintbrush Tuff, Yucca Mountain, Nye County, southern Nevada. 31 refs., 26 figs., 2 tabs

Neogene fallout tuffs from the Yellowstone hotspot in the Columbia Plateau region, Oregon, Washington and Idaho, USA.

Directory of Open Access Journals (Sweden)

Barbara P Nash

Full Text Available Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16-4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG, and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas.

G-tunnel welded tuff mining experiment preparations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Bellman, R.A. Jr.; Mann, K.L.; Zerga, D.P.

1991-01-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a mine-by in welded tuff so that predictive-type information could be obtained regarding the response of the rock to a drill and blast excavation process, where smooth blasting techniques were used. Included in the study were evaluations of and recommendations for various measurement systems that might be used in future mine-by efforts. This report summarizes the preparations leading to the recording of data. 17 refs., 27 figs., 5 tabs

HydroHillChart – Francis module. Software used to Calculate the Hill Chart of the Francis Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Dorian Nedelcu

2015-07-01

Full Text Available The paper presents the Hydro Hill Chart - Francis module application, used to calculate the hill chart of the Pelton, Francis and Kaplan hydraulic turbine models, by processing the data measured on the stand. After describing the interface and menu, the input data is graphically presented and the universal characteristic for measuring scenarios ao=const. and n11=const is calculated. Finally, the two calculated hill charts are compared through a graphical superimposition of the isolines.

27 CFR 9.190 - Red Hill Douglas County, Oregon.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Red Hill Douglas County... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

Magmatism, ash-flow tuffs, and calderas of the ignimbrite flareup in the western Nevada volcanic field, Great Basin, USA

Science.gov (United States)

Christopher D. Henry,; John, David A.

2013-01-01

The western Nevada volcanic field is the western third of a belt of calderas through Nevada and western Utah. Twenty-three calderas and their caldera-forming tuffs are reasonably well identified in the western Nevada volcanic field, and the presence of at least another 14 areally extensive, apparently voluminous ash-flow tuffs whose sources are unknown suggests a similar number of undiscovered calderas. Eruption and caldera collapse occurred between at least 34.4 and 23.3 Ma and clustered into five ∼0.5–2.7-Ma-long episodes separated by quiescent periods of ∼1.4 Ma. One eruption and caldera collapse occurred at 19.5 Ma. Intermediate to silicic lavas or shallow intrusions commonly preceded caldera-forming eruptions by 1–6 Ma in any specific area. Caldera-related as well as other magmatism migrated from northeast Nevada to the southwest through time, probably resulting from rollback of the formerly shallow-dipping Farallon slab. Calderas are restricted to the area northeast of what was to become the Walker Lane, although intermediate and effusive magmatism continued to migrate to the southwest across the future Walker Lane.Most ash-flow tuffs in the western Nevada volcanic field are rhyolites, with approximately equal numbers of sparsely porphyritic (≤15% phenocrysts) and abundantly porphyritic (∼20–50% phenocrysts) tuffs. Both sparsely and abundantly porphyritic rhyolites commonly show compositional or petrographic evidence of zoning to trachydacites or dacites. At least four tuffs have volumes greater than 1000 km3, with one possibly as much as ∼3000 km3. However, the volumes of most tuffs are difficult to estimate, because many tuffs primarily filled their source calderas and/or flowed and were deposited in paleovalleys, and thus are irregularly distributed.Channelization and westward flow of most tuffs in paleovalleys allowed them to travel great distances, many as much as ∼250 km (original distance) to what is now the western foothills of the

Experiences of fitting isotherms to data from batch sorption experiments for radionuclides on tuffs

International Nuclear Information System (INIS)

Polzer, W.L.; Fuentes, H.R.

1989-11-01

Laboratory experiments have been performed on the sorption of radionuclides on tuff as site characterization information for the Yucca Mountain Project. This paper presents general observations on the results of curve-fitting of sorption data by isotherm equations and the effects of experimental variables on their regressional analysis. Observations are specific to the effectiveness and problems associated with fitting isotherms, the calculation and value of isotherm parameters, and the significance of experimental variables such as replication, particle size, mode of sorption, and mineralogy. These observations are important in the design of laboratory experiments to ensure that collected data are adequate for effectively characterizing sorption of radionuclides on tuffs or other materials. 13 refs., 2 figs., 4 tabs

Scaling behavior of gas permeability measurements in volcanic tuffs

International Nuclear Information System (INIS)

Tidwell, V.C.

1994-01-01

One of the critical issues facing the Yucca Mountain site characterization and performance assessment programs is the manner in which property scaling is addressed. Property scaling becomes an issue whenever heterogeneous media properties are measured at one scale but applied at another. A research program has been established to challenge current understanding of property scaling with the aim of developing and testing models that describe scaling behavior in a quantitative manner. Scaling of constitutive rock properties is investigated through physical experimentation involving the collection of suites of gas-permeability data measured over a range of discrete scales. The approach is to systematically isolate those factors believed to influence property scaling and investigate their relative contributions to overall scaling behavior. Two blocks of tuff, each exhibiting differing heterogeneity structure, have recently been examined. Results of the investigation show very different scaling behavior, as exhibited by changes in the distribution functions and variograms, for the two tuff samples. Even for the relatively narrow range of measurement scales employed significant changes in the distribution functions, variograms, and summary statistics occurred. Because such data descriptors will likely play an important role in calculating effective media properties, these results demonstrate both the need to understand and accurately model scaling behavior

Mineralogic studies of tuff for high-level waste disposal

International Nuclear Information System (INIS)

Vaniman, D.; Bish, D.; Broxton, D.; Byers, F.; Carlos, B.; Levy, S.

1986-01-01

The volcanic rocks at Yucca Mountain, Nevada, consist predominantly of tuff that originated 12 to 14 million years ago as flows and airfalls of hot volcanic particulates. On cooling these units formed two major rock types: crystallized zones formed mostly of feldspar and silica minerals, and zones of glass. Alteration of glass to zeolite minerals occurred largely during structural tilting of Yucca Mountain in the ∼1-3 million years following the major eruptions. The compositions of zeolites formed from glasses strongly indicate open-system chemical exchange. Superimposed on this general alteration of glasses are areas of local high-temperature alteration. High-temperature alteration ended by 11 million years ago. Zeolites such as clinoptilolite persisted during high-temperature alteration at temperatures up to 100 degree C, suggesting that clinoptilolite at Yucca Mountain close to the thermally disturbed zone around a repository may also survive heating to temperatures at least this high. The mineralogic data from tuff at Yucca Mountain will ultimately be used by the Department of Energy Nevada Nuclear Waste storage Investigations for (1) defining the mineralogic component in estimating waste element travel times away from the repository and (2) determining the past history of alteration and the anticipated stability of minerals near the repository

Mineralogy, geochemistry and low grade metamorphism of green tuffs of Karaj formation in Hesarbon area (south west Firoozkooh

Directory of Open Access Journals (Sweden)

Shiva Bahrami

2017-03-01

Full Text Available Green tuffs of middle Eocene age in Hesarbon area, south west of Firoozkuh (East of Central Alborz consist of a thick sequence of lithic-, crystal-,vitric-and calcareous-tuffs. Microscopic and x-ray diffraction studies show plagioclase (albite and oligoclase, alkali feldspar (sanidine, quartz, cristobalite, biotite and hornblende are the major minerals in the rocks studied. Secondary minerals such as analcime, chlorite, prehnite and clay minerals are mainly present in the groundmass of the rocks. Extensive tectonic activities have created a variety of structural features including numerous folds and faults and therefore, have caused the green tuffs to be crushed and converted to breccia tuffs in many parts. Veins and cavities are filled by considerable amounts of zeolitic minerals including heulandite group, clinoptilolite and natrolite along with calcite and secondary quartz. Based on geochemical data, they lie on the dacite and rhyodacite field showing a calc-alkaline nature in the corresponding diagrams. According to the chondrite and primitive mantle normalized diagrams of trace elements, negative anomalies of Eu, Nb, Ti, P and depletion of HFSE together with their position in the petrogenesis discrimination diagrams, it is most likely that these rocks are formed in the active continental margin of a subduction zone. The existence of analcime and prehnite in the groundmass demonstrate that these rocks have undergone some degrees of low-grade metamorphism due to the overburden of the layers in the temperature range 200-300 °C. The present study shows that zeolite minerals filling the fractures and cavities of tuffs are precipitated by hydrothermal fluids with a neutral pH to acidic

Permeability and fluid chemistry studies of the Topopah Spring Member of the Paintbrush Tuff, Nevada Test Site: Part II

International Nuclear Information System (INIS)

Moore, D.E.; Morrow, C.A.; Byerlee, J.D.

1985-03-01

The Topopah Spring Member of the Paintbrush Tuff is being considered as a possible emplacement horizon for the disposal of nuclear waste. The permeability and pore-fluid chemistry of the Topopah Spring Member have been investigated experimentally. The work reported here represents a continuation of previous permeability studies on the Topopah Spring Member. Three experiments were run, to test the effect of pore pressure, sample orientation, and flow direction on permeability and pore fluid chemistry. In the experiments, water flowed either up or down a temperature gradient established across the tuff sample in response to a small pore pressure gradient. The maximum temperature of the gradient was 150 0 C, and the minimum was 43 to 45 0 C. The confining pressure was 100 bars, corresponding to a disposal depth of 400 meters. J13 water was the starting pore fluid. The heated tuff samples showed few changes in permeability from their initial, room-temperature values. In addition, the fluids discharged from both the low and high-temperature sides of the tuff samples were dilute, nearly neutral solutions whose compositions did not differ greatly from the starting J13 compositions. 16 refs., 14 figs., 4 tabs

Studies of the mobility of uranium and thorium in Nevada Test Site tuff

Energy Technology Data Exchange (ETDEWEB)

Wollenberg, H.A.; Flexser, S.; Smith, A.R. [Lawrence Berkeley Lab., CA (United States)

1991-06-01

Hydro-geochemical processes must be understood if the movement of radionuclides away from a breached radioactive waste canister is to be modeled and predicted. In this respect, occurrences of uranium and thorium in hydrothermal systems are under investigation in tuff and in rhyolitic tuff that was heated to simulate the effects of introduction of radioactive waste. In these studies, high-resolution gamma spectrometry and fission-track radiography are coupled with observations of alteration mineralogy and thermal history to deduce the evidence of, or potential for movement of, U and Th in response to the thermal environment. Observations to date suggest that U was mobile in the vicinity of the heater but that localized reducing environments provided by Fe-Ti-Mn-oxide minerals concentrated U and thus attenuated its migration.

Petrology and geochemistry of the Grouse Canyon Member of the Belted Range Tuff, Rock-Mechanics Drift, U12g Tunnel, Nevada Test Site

International Nuclear Information System (INIS)

Connolly, J.R.; Mansker, W.L.; Hicks, R.; Allen, C.C.; Husler, J.; Keil, K.; Lappin, A.R.

1983-04-01

G-Tunnel at Nevada Test Site (NTS) is the site of thermal and thermomechanical experiments examining the feasibility of emplacing heat-producing nuclear wastes in silicic tuffs. This report describes the general stratigraphy, mineralogy, and bulk chemistry of welded portions of the Grouse Canyon Member of the Belted Range Tuff, the unit in which most of these experiments will be performed. The geologic characteristics of the Grouse Canyon Member are compared with those of the Topopah Spring Member of the Paintbrush Tuff, presently the preferred horizon for an actual waste repository at Yucca Mountain, near the southwest boundary of Nevada Test Site. This comparison suggests that test results obtained in welded tuff from G-Tunnel are applicable, with limitations, to evaluation of the Topopah Spring Member at Yucca Mountain

Stable isotopes of authigenic minerals in variably-saturated fractured tuff

International Nuclear Information System (INIS)

Weber, D.S.; Evans, D.D.

1988-11-01

Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ( 18 O/ 16 O) and carbon ( 13 C/ 12 C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs

Stable isotopes of authigenic minerals in variably-saturated fractured tuff

Energy Technology Data Exchange (ETDEWEB)

Weber, D.S.; Evans, D.D.

1988-11-01

Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ({sup 18}O/{sup 16}O) and carbon ({sup 13}C/{sup 12}C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs.

Unsaturated Zone and Saturated Zone Transport Properties (U0100)

Energy Technology Data Exchange (ETDEWEB)

J. Conca

2000-12-20

This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

Completion report for Well ER-EC-6

Energy Technology Data Exchange (ETDEWEB)

M. J. Townsend

2000-05-01

Well ER-EC-6 was drilled for the U.S. Department of Energy, Nevada Operations Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in the spring of 1999 as part of the DOE's hydrogeologic investigation well program in the Western Pahute Mesa - Oasis Valley region just west of the Nevada Test Site. A 66-centimeter surface hole was drilled and cased off to the depth of 485.1 meters below the surface. The hole diameter was then decreased to 31.1 centimeters for drilling to a total depth of 1,524.0 meters. A preliminary composite, static, water level was measured at the depth of approximately 434.6 meters prior to installation of the completion string. One completion string with four isolated, slotted intervals was installed in the well. Detailed lithologic descriptions with preliminary stratigraphic assignments are included in the report. These are based on composite drill cuttings collected every 3 meters and 33 sidewall samples taken at various depths below 504.4 meters, supplemented by geophysical log data. Detailed chemical and mineralogical studies of rock samples are in progress. The well penetrated Tertiary-age lava and tuff of the Timber Mountain Group, the Paintbrush Group, the Calico Hills Formation, and the Volcanics of Quartz Mountain. Intense hydrothermal alteration was observed below the depth of 640 m. The preliminary geologic interpretation indicates that this site may be located on a buried structural ridge that separates the Silent Canyon and Timber Mountain caldera complexes.

Unsaturated Zone and Saturated Zone Transport Properties (U0100)

International Nuclear Information System (INIS)

Conca, J.

2000-01-01

This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion

The reaction of glass during gamma irradiation in a saturated tuff environment

International Nuclear Information System (INIS)

Ebert, W.L.; Bates, J.K.; Gerding, T.J.

1990-05-01

The reaction between tuffaceous groundwater and actinide-doped SRL 165 and PNL 76-68 type glasses in a gamma radiation field has been studied at 90 degree C for periods up to 278 days. The primary effect of the radiation field was the acidification of the leachate through the production of nitrogen acids. Acidification of the leachate was limited by bicarbonate in the groundwater, for all exposures tested. Nonirradiated experiments were performed to represent the lowest limit of radiation exposure. Both irradiated and nonirradiated experiments were performed with and without a tuff monolith present in the reaction vessel. Neither irradiation nor the presence of tuff had a major effect on the extent of glass reaction as measured by the leachate concentrations of various glass species or analysis of the reacted glass surfaces. This report discusses the results of leaching experiments performed in a gamma radiation field and in the absence of a radiation field. 28 refs., 47 figs., 11 tabs

Version II of the users manual for the Tuff Data Base Interface

International Nuclear Information System (INIS)

Welch, E.P.; Satter, B.J.; Langkopf, B.S.; Zeuch, D.H.

1987-05-01

The Nevada Nuclear Waste Storage Investigations (NNWSI) Project, managed by the Nevada Operations Office of the US Department of Energy, is investigating the feasibility of locating a repository at Yucca Mountain on and adjacent to the Nevada Test Site (NTS) in southern Nevada. A part of this investigation includes obtaining physical properties from laboratory tests on samples from Yucca Mountain and from field tests at Yucca Mountain. A computerized data base has been developed to store this data in a centralized location. The data base is stored on the Cyber 170/855 computer at Sandia using the System 2000 Data Base Management software. A user-friendly interface, the Tuff Data Base Interface (the Interface), allows NNWSI participants to retrieve data from the Tuff Data Base. The Interface gives users flexibility to retrieve portions of the Data Base related to their interests. This report gives basic instructions on accessing the Sandia computing system and explains how to use the Interface. 18 figs., 5 tabs

Fluid flow in 0.5-m scale blocks of Topopah Spring tuff

International Nuclear Information System (INIS)

Blair, S. C.; Carlson, S. R.; Constantino, M. S.

1999-01-01

A laboratory experiment was conducted on a 0.5-m scale block of Topopah Spring tuff, to measure fluid flow and mechanical deformation properties under conditions that approximate the near-field environment of a potential nuclear waste repository, and to provide an intermediate-scale test case for numerical model validation. The test specimen is a 0.25 x 0.25 x 0.50 m rectangular prism bisected by an artificial (saw-cut) fracture orthogonal to the tuff fabric. Water was supplied by a point source at the center of the fracture under various pressures of up to 0.04 MPa. Both fluid flow and mechanical properties were found to be anisotropic and strongly correlated with the ash flow fabric. Fluid mass-balance measurements revealed that only minor imbibition of water occurred through the fracture surfaces and that flow rates were independent of normal stress to 14.0 MPa and temperature to 140 C. Flow through the fracture occurred largely through uncorrelated porosity that intersected the fracture plane

In defense of Magnetite-Ilmenite Thermometry in the Bishop Tuff and its implication for gradients in silicic magma reservoirs

Science.gov (United States)

Evans, Bernard W; Hildreth, Edward; Bachmann, Olivier; Scaillet, Bruno

2016-01-01

Despite claims to the contrary, the compositions of magnetite and ilmenite in the Bishop Tuff correctly record the changing conditions of T and fO2 in the magma reservoir. In relatively reduced (∆NNO magmas (e.g., Bishop Tuff, Taupo units), Ti behaves compatibly (DTi ≈ 2-3.5), leading to a decrease in TiO2 activity in the melt with cooling and fractionation. In contrast, FeTi-oxides are poorer in TiO2 in more oxidized magmas (∆NNO > 1, e.g., Fish Canyon Tuff, Pinatubo), and the d(aTiO2)/dT slope can be negative. Biotite, FeTi-oxides, liquid, and possibly plagioclase largely maintained equilibrium in the Bishop Tuff magma (unlike the pyroxenes, and cores of quartz, sanidine, and zircon) prior ro and during a mixing event triggered by a deeper recharge, which, based on elemental diffusion profiles in minerals, took place at least several decades before eruption. Equilibrating phases and pumice compositions show evolving chemical variations that correlate well with mutually consistent temperatures based on the FeTi-oxides, sanidine-plagioclase, and ∆18O quartz-magnetite pairs. Early Bishop Tuff (EBT) temperatures are lower (700 to ~780‎°C) than temperatures (780 to >820°C) registered in Late Bishop Tuff (LBT), the latter defined here not strictly stratigraphically, but by the presence of orthopyroxene and reverse-zoned rims on quartz and sanidine. The claimed similarity in compositions, Zr-saturation temperatures and thermodynamically calculated temperatures (730-740°C) between EBT and less evolved LBT reflect the use of glass inclusions in quartz cores in LBT that were inherited from the low temperature rhyolitic part of the reservoir characteristic of the EBT. LBT temperatures as high as 820°C, the preservation of orthopyroxene, and the presence of reverse-zoned minerals (quartz, sanidine, zircons) are consistent with magma recharge at the base of the zoned reservoir, heating the cooler rhyolitic melt, partly remelting cumulate mush, and introducing

HydroHillChart – Pelton module. Software used to Calculate the Hill Chart of the Pelton Hydraulic Turbines

OpenAIRE

Dorian Nedelcu; Adelina Bostan; Florin Peris-Bendu

2015-01-01

The paper presents the HydroHillChart - Pelton module application, used to calculate the hill chart of the Pelton hydraulic turbine models, by processing the data measured on the stand. In addition, the tools offered by the application such as: interface, menu, input data, numerical and graphical results, etc. are described.

Preliminary modeling of moisture movement in the tuff beneath Mortandad Canyon, Los Alamos National Laboratory

International Nuclear Information System (INIS)

Geddis, A.M.

1992-01-01

An area of upper/middle Mortandad Canyon on the Los Alamos National Laboratory is modeled in cross-section. UNSAT2, a finite element model (FEM) is used to predict moisture movement. Hydraulic characteristics of the tuff are described by van Genuchten parameters determined from laboratory tests on cores taken from a borehole within the cross-section. Material properties are distributed horizontal planar in space to cover the solution domain with required initial conditions. An estimate of seepage flux from a thin perched alluvial aquifer into the upper surface of the tuff is taken from a lumped parameter model. Moisture redistribution for a ponded boundary condition and a larger flux is investigated. A composite simulation using material properties from two separate coreholes is also evaluated

Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

Science.gov (United States)

Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.;

The Bradford Hill considerations on causality: a counterfactual perspective

Directory of Open Access Journals (Sweden)

Höfler Michael

2005-11-01

Full Text Available Abstract Bradford Hill's considerations published in 1965 had an enormous influence on attempts to separate causal from non-causal explanations of observed associations. These considerations were often applied as a checklist of criteria, although they were by no means intended to be used in this way by Hill himself. Hill, however, avoided defining explicitly what he meant by "causal effect". This paper provides a fresh point of view on Hill's considerations from the perspective of counterfactual causality. I argue that counterfactual arguments strongly contribute to the question of when to apply the Hill considerations. Some of the considerations, however, involve many counterfactuals in a broader causal system, and their heuristic value decreases as the complexity of a system increases; the danger of misapplying them can be high. The impacts of these insights for study design and data analysis are discussed. The key analysis tool to assess the applicability of Hill's considerations is multiple bias modelling (Bayesian methods and Monte Carlo sensitivity analysis; these methods should be used much more frequently.

A performance assessment methodology for high-level radioactive waste disposal in unsaturated, fractured tuff

International Nuclear Information System (INIS)

Gallegos, D.P.

1991-07-01

Sandia National Laboratories, has developed a methodology for performance assessment of deep geologic disposal of high-level nuclear waste. The applicability of this performance assessment methodology has been demonstrated for disposal in bedded salt and basalt; it has since been modified for assessment of repositories in unsaturated, fractured tuff. Changes to the methodology are primarily in the form of new or modified ground water flow and radionuclide transport codes. A new computer code, DCM3D, has been developed to model three-dimensional ground-water flow in unsaturated, fractured rock using a dual-continuum approach. The NEFTRAN 2 code has been developed to efficiently model radionuclide transport in time-dependent velocity fields, has the ability to use externally calculated pore velocities and saturations, and includes the effect of saturation dependent retardation factors. In order to use these codes together in performance-assessment-type analyses, code-coupler programs were developed to translate DCM3D output into NEFTRAN 2 input. Other portions of the performance assessment methodology were evaluated as part of modifying the methodology for tuff. The scenario methodology developed under the bedded salt program has been applied to tuff. An investigation of the applicability of uncertainty and sensitivity analysis techniques to non-linear models indicate that Monte Carlo simulation remains the most robust technique for these analyses. No changes have been recommended for the dose and health effects models, nor the biosphere transport models. 52 refs., 1 fig

Preliminary geologic and geophysical data of the UE25a-3 exploratory drill hole, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

Maldonado, F.; Muller, D.C.; Morrison, J.N.

1979-09-01

The UE25a-3 drill hole, located in the Calico Hills area, was drilled as part of an effort to evaluate the Calico Hills area as a possible nuclear waste repository site. The purpose of the drill hole was to verify the existence of an intrusive crystalline body in the subsurface and to determine the stratigraphy, structure, and nature of fractures of the cored rocks. Cored samples were obtained for mineral, chemical, and material property analyses. Numerous high-angle faults and brecciated zones were intersected by the drill hole. The units cored were intensely fractured with fracture analysis of the core consisting of frequency of fractures, dips of fractures, open and closed (sealed) fractures and types of fracture sealing or coating material. Twenty-four hundred and thirty fractures, representing approximately 30 percent of the fractures present, indicate an average fracture frequency of 13.2 fractures per meter, predominantly high-angle dips with 66 percent of the fractures closed. Fractures in the argillite interval are sealed or coated predominantly with kaolinite, nacrite, and dickite. Calcite, chlorite, and magnetite are present in fractures in the altered argillite interval. Fractures in the marble interval are sealed or coated with calcite, dolomite, and ferruginous clay. The core index indicates that the lower half of the drilled interval is more competent than the upper half. Borehole geophysical logs were run by the Birdwell Division of Seismograph Service Corporation for geologic correlations and lithologic characterizations. The logs include: caliper, density, resistivity, spontaneous potential, Vibroseis, 3-D velocity, neutron, and gamma-ray logs

HydroHillChart – Pelton module. Software used to Calculate the Hill Chart of the Pelton Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Dorian Nedelcu

2015-07-01

Full Text Available The paper presents the HydroHillChart - Pelton module application, used to calculate the hill chart of the Pelton hydraulic turbine models, by processing the data measured on the stand. In addition, the tools offered by the application such as: interface, menu, input data, numerical and graphical results, etc. are described.

The Camp Hill Project: Objectives and Design

Science.gov (United States)

Mattingly, John B.

1976-01-01

Available from: EC 090 474. Outlined are the problems and objectives of Pennsylvania's Camp Hill Project--a program designed to complete psychological needs assessments for juveniles incarcerated at Camp Hill, to develop project policies and guidelines in preparation for meeting with juvenile court judges, and to hire staff. (SBH)

Stress-corrosion-cracking studies on candidate container alloys for the Tuff Repository

International Nuclear Information System (INIS)

Beavers, J.A.; Durr, C.L.

1992-05-01

Cortest Columbus Technologies, Inc. (CC Technologies) investigated the long-term performance of container materials used for high-level waste package as part of the information needed by the Nuclear Regulatory Commission (NRC) to assess the Department of Energy's application to construct to geologic repository for high-level radioactive waste. At the direction of the NRC, the program focused on the Tuff Repository. This report summarizes the results of Stress-Corrosion-Cracking (SCC) studies performed in Tasks 3, 5, and 7 of the program. Two test techniques were used; U-bend exposures and Slow-Strain-Rate (SSR) tests. The testing was performed on two copper-base alloys (Alloy CDA 102 and Alloy CDA 175) and two Fe-Cr-Ni alloys (Alloy 304L and Alloy 825) in simulated J-13 groundwater and other simulated solutions for the Tuff Repository. These solutions were designed to simulate the effects of concentration and irradiation on the groundwater composition. All SCC testing on the Fe-Cr-Ni Alloys was performed on solution-annealed specimens and thus issues such as the effect of sensitization on SCC were not addressed

Studies of ancient concrete as analogs of cementitious sealing materials for a repository in tuff

Energy Technology Data Exchange (ETDEWEB)

Roy, D.M.; Langton, C.A.

1989-03-01

The durability of ancient cementitious materials has been investigated to provide data applicable to determining the resistance to weathering of concrete materials for sealing a repository for storage of high-level radioactive waste. Because tuff and volcanic ash are used in the concretes in the vicinity of Rome, the results are especially applicable to a waste repository in tuff. Ancient mortars, plasters, and concretes collected from Rome, Ostia, and Cosa dating to the third century BC show remarkable durability. The aggregates used in the mortars, plasters, and concretes included basic volcanic and pyroclastic rocks (including tuff), terra-cotta, carbonates, sands, and volcanic ash. The matrices of ancient cementitious materials have been characterized and classified into four categories: (1) hydraulic hydrated lime and hydrated lime cements, (2) hydraulic aluminous and ferruginous hydrated lime cements ({plus_minus} siliceous components), (3) pozzolana/hydrated lime cements, and (4) gypsum cements. Most of the materials investigated are in category (3). The materials were characterized to elucidate aspects of the technology that produced them and their response to the environmental exposure throughout their centuries of existence. Their remarkable properties are the result of a combination of chemical, mineralogical, and microstructural factors. Their durability was found to be affected by the matrix mineralogy, particle size, and porosity; aggregate type, grading and proportioning; and the methodology of placement. 30 refs.

Analysis of Conservative Tracer Tests in the Bullfrog, Tram, and Prow Pass Tuffs, 1996 to 1998, Yucca Mountain, Nye County, Nevada

Science.gov (United States)

Umari, Amjad; Fahy, Michael F.; Earle, John D.; Tucci, Patrick

2008-01-01

To evaluate the potential for transport of radionuclides in ground water from the proposed high-level nuclear-waste repository at Yucca Mountain, Nevada, conservative (nonsorbing) tracer tests were conducted among three boreholes, known as the C-hole Complex, and values for transport (or flow) porosity, storage (or matrix) porosity, longitudinal dispersivity, and the extent of matrix diffusion were obtained. The C-holes are completed in a sequence of Miocene tuffaceous rock, consisting of nonwelded to densely welded ash-flow tuff with intervals of ash-fall tuff and volcaniclastic rocks, covered by Quaternary alluvium. The lower part of the tuffaceous-rock sequence includes the Prow Pass, Bullfrog, and Tram Tuffs of the Crater Flat Group. The rocks are pervaded by tectonic and cooling fractures. Paleozoic limestone and dolomite underlie the tuffaceous rocks. Four radially convergent and one partially recirculating conservative (nonsorbing) tracer tests were conducted at the C-hole Complex from 1996 to 1998 to establish values for flow porosity, storage porosity, longitudinal dispersivity, and extent of matrix diffusion in the Bullfrog and Tram Tuffs and the Prow Pass Tuff. Tracer tests included (1) injection of iodide into the combined Bullfrog-Tram interval; (2) injection of 2,6 difluorobenzoic acid into the Lower Bullfrog interval; (3) injection of 3-carbamoyl-2-pyridone into the Lower Bullfrog interval; and (4) injection of iodide and 2,4,5 trifluorobenzoic acid, followed by 2,3,4,5 tetrafluorobenzoic acid, into the Prow Pass Tuff. All tracer tests were analyzed by the Moench single- and dual-porosity analytical solutions to the advection-dispersion equation or by superposition of these solutions. Nonlinear regression techniques were used to corroborate tracer solution results, to obtain optimal parameter values from the solutions, and to quantify parameter uncertainty resulting from analyzing two of the three radially convergent conservative tracer tests

After runaway: The trans-Hill stage of planetesimal growth

International Nuclear Information System (INIS)

Lithwick, Yoram

2014-01-01

When planetesimals begin to grow by coagulation, they first enter an epoch of runaway, during which the biggest bodies grow faster than all the others. The questions of how runaway ends and what comes next have not been answered satisfactorily. We show that runaway is followed by a new stage—the 'trans-Hill stage'—that commences when the bodies that dominate viscous stirring ('big bodies') become trans-Hill, i.e., when their Hill velocity matches the random speed of the small bodies they accrete. Subsequently, the small bodies' random speed grows in lockstep with the big bodies' sizes, such that the system remains in the trans-Hill state. Trans-Hill growth is crucial for determining the efficiency of growing big bodies, as well as their growth timescale and size spectrum. Trans-Hill growth has two sub-stages. In the earlier one, which occurs while the stirring bodies remain sufficiently small, the evolution is collisionless, i.e., collisional cooling among all bodies is irrelevant. The efficiency of forming big bodies in this collisionless sub-stage is very low, ∼10α << 1, where α ∼ 0.005(a/AU) –1 is the ratio between the physical size of a body and its Hill radius. Furthermore, the size spectrum is flat (equal mass per size decade, i.e., q = 4). This collisionless trans-Hill solution explains results from previous coagulation simulations for both the Kuiper Belt and the asteroid belt. The second trans-Hill sub-stage commences once the stirring bodies grow big enough (>α –1 × the size of the accreted small bodies). After that time, collisional cooling among small bodies controls the evolution. The efficiency of forming big bodies rises and the size spectrum becomes more top heavy. Trans-Hill growth can terminate in one of two ways, depending on the sizes of the small bodies. First, mutual accretion of big bodies can become significant and conglomeration proceeds until half of the total mass is converted into big bodies

Accounting for imperfect detection in Hill numbers for biodiversity studies

Science.gov (United States)

Broms, Kristin M.; Hooten, Mevin B.; Fitzpatrick, Ryan M.

2015-01-01

Hill numbers unify biodiversity metrics by combining several into one expression. For example, species richness, Shannon's diversity index and the Gini–Simpson index are a few of the most used diversity measures, and they can be expressed as Hill numbers. Traditionally, Hill numbers have been calculated from relative abundance data, but the expression has been modified to use incidence data as well. We demonstrate an approach for estimating Hill numbers using an occupancy modelling framework that accounts for imperfect detection.

A language for image processing HILLS and its supporting system SDIP

International Nuclear Information System (INIS)

Suzuki, H.; Toriwaki, J.

1984-01-01

This paper presents a language HILLS and its supporting system SDIP for image processing. HILLS is a key-word type language for describing image processing procedures by using subroutine packages SLIP and SPIDER. SDIP, written in FORTRAN to keep portability, supports programming by HILLS in interactive mode including functions such as editing, translating HILLS into FORTRAN, error detection, and providing manual information. Results of preliminary experiments suggest that HILLS and SDIP are very useful tools for beginners and researchers in application fields of image processing to develop desired image analysis procedures

Laboratory testing of cement grouting of fractures in welded tuff

International Nuclear Information System (INIS)

Sharpe, C.J.; Daemen, J.J.

1991-03-01

Fractures in the rock mass surrounding a repository and its shafts, access drifts, emplacement rooms and holes, and exploratory or in-situ testing holes, may provide preferential flowpaths for the flow of groundwater or air, potentially containing radionuclides. Such cracks may have to be sealed. The likelihood that extensive or at least local grouting will be required as part of repository sealing has been noted in numerous publications addressing high level waste repository closing. The objective of this work is to determine the effectiveness of fracture sealing (grouting) in welded tuff. Experimental work includes measurement of intact and fracture permeability under various normal stresses and injection pressures. Grout is injected into the fractures. The effectiveness of grouting is evaluated in terms of grout penetration and permeability reduction, compared prior to and after grouting. Analysis of the results include the effect of normal stress, injection pressure, fracture roughness, grout rheology, grout bonding, and the radial extent of grout penetration. Laboratory experiments have been performed on seventeen tuff cylinders with three types of fractures: (1) tension induced cracks, (2) natural fractures, and (3) sawcuts. Prior to grouting, the hydraulic conductivity of the intact rock and of the fractures is measured under a range of normal stresses. The surface topography of the fracture is mapped, and the results are used to determine aperture distributions across the fractures. 72 refs., 76 figs., 25 tabs

The influence of water on the strength of Neapolitan Yellow Tuff, the most widely used building stone in Naples (Italy)

Science.gov (United States)

Heap, Michael J.; Farquharson, Jamie I.; Kushnir, Alexandra R. L.; Lavallée, Yan; Baud, Patrick; Gilg, H. Albert; Reuschlé, Thierry

2018-06-01

Neapolitan Yellow Tuff (NYT) has been used in construction in Naples (Italy) since the Greeks founded the city—then called Neapolis—in the sixth century BCE. We investigate here whether this popular building stone is weaker when saturated with water, an issue important for assessments of weathering damage and monument preservation. To this end, we performed 28 uniaxial compressive strength measurements on dry and water-saturated samples cored from a block of the lithified Upper Member of the NYT. Our experiments show that the strength of the zeolite-rich NYT is systematically reduced when saturated with water (the ratio of wet to dry strength is 0.63). Complementary experiments show that two other common Neapolitan building stones—Piperno Tuff and the grey Campanian Ignimbrite (both facies of the Campanian Ignimbrite deposit devoid of zeolites)—do not weaken when wet. From these data, and previously published data for tuffs around the globe, we conclude that the water-weakening in NYT is a consequence of the presence of abundant zeolites (the block tested herein contains 46 wt.% of zeolites). These data may help explain weathering damage in NYT building stones (due to rainfall, rising damp, and proximity to the sea or water table) and the observed link between rainfall and landslides, rock falls, and sinkhole formation in Naples, and the weathering of other buildings built from zeolite-rich tuffs worldwide.

27 CFR 9.162 - Sta. Rita Hills.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Sta. Rita Hills. 9.162.... Rita Hills. (a) Name. The name of the viticultural area described in this section is “Sta. Rita Hills”. For purposes of part 4 of this chapter, “Sta. Rita Hills” is a term of viticultural significance. (b...

Biogeography of the Shimba Hills ecosystem herpetofauna in Kenya.

Science.gov (United States)

Malonza, Patrick K; Mulwa, David M; Nyamache, Joash O; Jones, Georgina

2018-03-18

The Shimba Hills ecosystem along the south coast of Kenya is a key East African biodiversity hotspot. Historically, it is biogeographically assignable to the East African coastal biome. We examined the current Shimba Hills herpetofauna and their zoogeographical affinities to the coastal forests and nearby Eastern Arc Mountains biodiversity hotspots. The key studied sites included the Shimba Hills National Reserve, forest reserves, Kaya forests, and adjacent private land. Data on herpetofaunal richness were obtained from recent field surveys, literature, and specimens held at the National Museums of Kenya, Herpetology Section Collection, Nairobi. The Makadara, Mwele, and Longo-Mwagandi forests within the Shimba Hills National Reserve hosted the highest number of unique and rare species. Generally, the forest reserves and Kaya forests were important refuges for forest-associated species. On private land, Mukurumudzi Dam riparian areas were the best amphibian habitat and were host to three IUCN (Red List) Endangered-EN amphibian species, namely, Boulengerula changamwensis, Hyperolius rubrovermiculatus, and Afrixalus sylvaticus, as well as one snake species Elapsoidea nigra. Using herpetofauna as zoogeographic indicators, the Shimba Hills were determined to be at a crossroads between the coastal forests (13 endemic species) and the Eastern Arc Mountains (seven endemic species). Most of the Eastern Arc Mountains endemic species were from recent records, and thus more are likely to be found in the future. This 'hybrid' species richness pattern is attributable to the hilly topography of the Shimba Hills and their proximity to the Indian Ocean. This has contributed to the Shimba Hills being the richest herpetofauna area in Kenya, with a total of 89 and 36 reptile and amphibian species, respectively. Because of its unique zoogeography, the Shimba Hills ecosystem is undoubtedly a key biodiversity area for conservation investment.

Audio-magnetotelluric (AMT) study to investigate the genesis of Mujil hill

Science.gov (United States)

Rahmania, Suryanto, Wiwit

2017-07-01

Gunung Mujil is an isolated hill located near Pondoworejo village, Kalibawang sub-district, Kulon Progo district, and Special Province of Yogyakarta. The hill is part of the eastern Kulon Progo mountain range extended relatively in the North-South direction. The lithology of the hill consists of andesite breccia and it's similar with the Old Andesite Formation that built the Kulon Progo Mountains. There are at least two hypothesis about the genesis and the formation mechanism of this hill, (1) it was formed by debris mass from Kulon Progo Mountains, and (2) ) it was formed by an intrusion. Our study intended to determine the subsurface resistivity below the hill and to relating those results to with the scenario of the genesis of the Mujil hill. We conducted Audio-magnetotellurics (AMT) measurements along two lines survey crossing the Mujil hill consisting of 20 measurements. Since the measurements are located near the villages, most of the data has a fair to bad quality and only one station yielded an excellent data. A 1D Forward modeling was then applied to find best-fit model of the AMT data. The results shows that the Mujil hill was built by debris mass of the Old Andesite Formation from Kulon Progo mountain which is represented by a lower resistivity value under the Mujil hill.

Strontium isotope evolution of pore water and calcite in the Topopah Spring Tuff, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Marshall, Brian D.; Futa, Kiyoto

2001-01-01

Pore water in the Topopah Spring Tuff has a narrow range of (delta) 87 Sr values that can be calculated from the (delta) 87 Sr values of the rock considering advection through and reaction with the overlying nonwelded tuffs of the PTn. This model can be extended to estimate the variation of (delta) 87 Sr in the pore water through time; this approximates the variation of (delta) 87 Sr measured in calcite fracture coatings. In samples of calcite where no silica can be dated by other methods, strontium isotope data may be the only method to determine ages. In addition, other Sr-bearing minerals in the calcite and opal coatings, such as fluorite, may be dated using the same model

A high-pyrite semianthracite of Late Permian age in the Songzao Coalfield, southwestern China: Mineralogical and geochemical relations with underlying mafic tuffs

Science.gov (United States)

Dai, S.; Wang, X.; Chen, W.; Li, D.; Chou, C.-L.; Zhou, Y.; Zhu, Chen; Li, H.; Zhu, Xudong; Xing, Y.; Zhang, W.; Zou, J.

2010-01-01

The No. 12 Coal (Late Permian) in the Songzao Coalfield, Chongqing, southwestern China, is characteristically high in pyrite and some trace elements. It is uniquely deposited directly above mafic tuff beds. Samples of coal and tuffs have been studied for their mineralogy and geochemistry using inductively coupled plasma-mass spectrometry, X-ray fluorescence, plasma low-temperature ashing plus powder X-ray diffraction, and scanning electron microscopy equipped with energy-dispersive X-ray analysis.The results show that the minerals of the No. 12 Coal are mainly composed of pyrite, clay minerals (kaolinite, chamosite, and illite), ankerite, calcite, and trace amounts of quartz and boehmite. Kaolinite and boehmite were mainly derived from sediment source region of mafic tuffs. Chamosite was formed by the reaction of kaolinite with Fe-Mg-rich fluids during early diagenesis. The high pyrite (Sp,d=8.83%) in the coal was related to marine transgression over peat deposits and abundant Fe derived from the underlying mafic tuff bed. Ankerite and calcite were precipitated from epigenetic fluids.Chemical compositions of incompatible elements indicate that the tuffs were derived from enriched mantle and the source magmas had an alkali-basalt character. Compared to other coals from the Songzao Coalfield and common Chinese coals, the No. 12 Coal has a lower SiO2/Al2O3 (1.13) but a higher Al2O3/Na2O (80.1) value and is significantly enriched in trace elements including Sc (13.5??g/g), V (121??g/g), Cr (33.6??g/g), Co (27.2??g/g), Ni (83.5??g/g), Cu (48.5??g/g), Ga (17.3??g/g), Y (68.3??g/g), Zr (444??g/g), Nb (23.8??g/g), and REE (392??g/g on average). Above mineralogical compositions, as well as similar ratios of selected elements (e.g., SiO2/Al2O3 and Al2O3/Na2O) and similar distribution patterns of incompatible elements (e.g., the mantle-normalized diagram for incompatible elements and chondrite-normalized diagram for rare earth elements) of coal and tuff, indicated that

A high-pyrite semianthracite of Late Permian age in the Songzao Coalfield, southwestern China: Mineralogical and geochemical relations with underlying mafic tuffs

Energy Technology Data Exchange (ETDEWEB)

Dai, Shifeng; Wang, Xibo; Chen, Wenmei [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, (China); Li, Dahua [Research Center of State Key Laboratory of Coal Resources and Safe Mining, Chongqing 400042, (China); Chou, Chen-Lin [Illinois State Geological Survey (Emeritus), 615 East Peabody Drive, Champaign, IL 61820, (United States); Zhou, Yiping [Yunnan Institute of Coal Geology Prospection, Kunming 650218, (China); Zhu, Changsheng; Li, Hang [Research Center of State Key Laboratory of Coal Resources and Safe Mining, Chongqing 400042, (China); Zhu, Xingwei; Xing, Yunwei; Zhang, Weiguo; Zou, Jianhua [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, (China)

2010-09-01

The No. 12 Coal (Late Permian) in the Songzao Coalfield, Chongqing, southwestern China, is characteristically high in pyrite and some trace elements. It is uniquely deposited directly above mafic tuff beds. Samples of coal and tuffs have been studied for their mineralogy and geochemistry using inductively coupled plasma-mass spectrometry, X-ray fluorescence, plasma low-temperature ashing plus powder X-ray diffraction, and scanning electron microscopy equipped with energy-dispersive X-ray analysis. The results show that the minerals of the No. 12 Coal are mainly composed of pyrite, clay minerals (kaolinite, chamosite, and illite), ankerite, calcite, and trace amounts of quartz and boehmite. Kaolinite and boehmite were mainly derived from sediment source region of mafic tuffs. Chamosite was formed by the reaction of kaolinite with Fe-Mg-rich fluids during early diagenesis. The high pyrite (S{sub p,d} 8.83%) in the coal was related to marine transgression over peat deposits and abundant Fe derived from the underlying mafic tuff bed. Ankerite and calcite were precipitated from epigenetic fluids. Chemical compositions of incompatible elements indicate that the tuffs were derived from enriched mantle and the source magmas had an alkali-basalt character. Compared to other coals from the Songzao Coalfield and common Chinese coals, the No. 12 Coal has a lower SiO{sub 2}/Al{sub 2}O{sub 3} (1.13) but a higher Al{sub 2}O{sub 3}/Na{sub 2}O (80.1) value and is significantly enriched in trace elements including Sc (13.5 {mu}g/g), V (121 {mu}g/g), Cr (33.6 {mu}g/g), Co (27.2 {mu}g/g), Ni (83.5 {mu}g/g), Cu (48.5 {mu}g/g), Ga (17.3 {mu}g/g), Y (68.3 {mu}g/g), Zr (444 {mu}g/g), Nb (23.8 {mu}g/g), and REE (392 {mu}g/g on average). Above mineralogical compositions, as well as similar ratios of selected elements (e.g., SiO{sub 2}/Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/Na{sub 2}O) and similar distribution patterns of incompatible elements (e.g., the mantle-normalized diagram for

Use of Rhenish tuff and trass in the Netherlands in the past two millenia

NARCIS (Netherlands)

Nijland, T.G.; Hees, R.P.J. van

2017-01-01

Occasionally, a profound but distant connection between volcanos and culture exists. This is the case for the volcanic Eifel region in Germany and historic construction in the Netherlands, with the river Rhine as physical and enabling connection. Volcanic tuff from the Eifel comprises a significant

Accumulation, biotransformation, histopathology and paralysis in the Pacific calico scallop Argopecten ventricosus by the paralyzing toxins of the dinoflagellate Gymnodinium catenatum.

Science.gov (United States)

Escobedo-Lozano, Amada Y; Estrada, Norma; Ascencio, Felipe; Contreras, Gerardo; Alonso-Rodriguez, Rosalba

2012-05-01

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.

Geotechnical instrumentation requirements for atdepth testing and repository monitoring in tuff

International Nuclear Information System (INIS)

Zimmerman, R.M.

1983-01-01

This paper outlines geotechnical instrumentation requirements for the possible establishment of a nuclear waste repository in tuff on the Nevada Test Site (NTS). The Nuclear Regulatory Commission (NRC) has specified a continuing program to confirm performance during the operational period of the repository, which could last 50 years. Minimum required geotechnical measurements for confirmation of performance include thermal and thermomechanical responses; changes in stress, strain, and displacements; and pore pressure and groundwater flow characteristics. Conditions expected in tuff are: maximum rock temperatures of less than 250 0 C, stresses less than 100 MPa, strains between + or -0.01 mm/mm, and pore pressures less than 35 KPa in the unsaturated zone where hydraulic head is not the primary contributor. The paper describes instrumentation needed to make the desired measurements. In general, the instrumentation and data system are required to be stable and reliable for tens of years. Designs must consider requirements for temperature stability, temperature expansion compensation, moisture resistance, and long-term durability in mining-type environments. Severe requirements such as these suggest consideration of techniques for in-situ replacement of instrumentation. State-of-the-art instrumentation is briefly described along with a discussion of needs for refinement, replacement/recalibration and instrumentation development

Nuclear-waste-package program for high-level isolation in Nevada tuff

International Nuclear Information System (INIS)

Rothman, A.J.

1982-01-01

The objective of the waste package program is to insure that a package is designed suitable for a repository in tuff that meets performance requirements of the NRC. In brief, the current (draft) regulation requires that the radionuclides be contained in the engineered system for 1000 years, and that, thereafter, no more than one part in 10 5 of the nuclides per year leave the boundary of the system. Studies completed as of this writing are thermal modeling of waste packages in a tuff repository and analysis of sodium bentonite as a potential backfill material. Both studies will be presented. Thermal calculations coupled with analysis of the geochemical literature on bentonite indicate that extensive chemical and physical alteration of bentonite would result at the high power densities proposed (ca. 2 kW/package and an area density of 25 W/m 2 ), in part due to compacted bentonite's relatively low thermal conductivity when dehydrated (approx. 0.6 +- 0.2 W/m 0 C). Because our groundwater contains K + , an upper hydrothermal temperature limit appears to be 120 to 150 0 C. At much lower power densities (less than 1 kW per package and an areal density of 12 W/m 2 ), bentonite may be suitable

Hume, Mill, Hill, and the sui generis epidemiologic approach to causal inference.

Science.gov (United States)

Morabia, Alfredo

2013-11-15

The epidemiologic approach to causal inference (i.e., Hill's viewpoints) consists of evaluating potential causes from the following 2, noncumulative angles: 1) established results from comparative, observational, or experimental epidemiologic studies; and 2) reviews of nonepidemiologic evidence. It does not involve statements of statistical significance. The philosophical roots of Hill's viewpoints are unknown. Superficially, they seem to descend from the ideas of Hume and Mill. Hill's viewpoints, however, use a different kind of evidence and have different purposes than do Hume's rules or Mill's system of logic. In a nutshell, Hume ignores comparative evidence central to Hill's viewpoints. Mill's logic disqualifies as invalid nonexperimental evidence, which forms the bulk of epidemiologic findings reviewed from Hill's viewpoints. The approaches by Hume and Mill cannot corroborate successful implementations of Hill's viewpoints. Besides Hume and Mill, the epidemiologic literature is clueless about a plausible, pre-1965 philosophical origin of Hill's viewpoints. Thus, Hill's viewpoints may be philosophically novel, sui generis, still waiting to be validated and justified.

Weak Properties and Robustness of t-Hill Estimators

Czech Academy of Sciences Publication Activity Database

Jordanova, P.; Fabián, Zdeněk; Hermann, P.; Střelec, L.; Rivera, A.; Girard, S.; Torres, S.; Stehlík, M.

2016-01-01

Roč. 19, č. 4 (2016), s. 591-626 ISSN 1386-1999 Institutional support: RVO:67985807 Keywords : asymptotic properties of estimators * point estimation * t-Hill estimator * t-lgHill estimator Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.679, year: 2016

Probing the volcanic-plutonic connection and the genesis of crystal-rich rhyolite in a deeply dissected supervolcano in the Nevada Great Basin: Source of the late Eocene Caetano Tuff

Science.gov (United States)

Watts, Kathryn E.; John, David A.; Colgan, Joseph P.; Henry, Christopher D.; Bindeman, Ilya N.; Schmitt, Axel K.

2016-01-01

Late Cenozoic faulting and large-magnitude extension in the Great Basin of the western USA has created locally deep windows into the upper crust, permitting direct study of volcanic and plutonic rocks within individual calderas. The Caetano caldera in north–central Nevada, formed during the mid-Tertiary ignimbrite flare-up, offers one of the best exposed and most complete records of caldera magmatism. Integrating whole-rock geochemistry, mineral chemistry, isotope geochemistry and geochronology with field studies and geologic mapping, we define the petrologic evolution of the magmatic system that sourced the >1100 km3Caetano Tuff. The intra-caldera Caetano Tuff is up to ∼5 km thick, composed of crystal-rich (30–45 vol. %), high-silica rhyolite, overlain by a smaller volume of comparably crystal-rich, low-silica rhyolite. It defies classification as either a monotonous intermediate or crystal-poor zoned rhyolite, as commonly ascribed to ignimbrite eruptions. Crystallization modeling based on the observed mineralogy and major and trace element geochemistry demonstrates that the compositional zonation can be explained by liquid–cumulate evolution in the Caetano Tuff magma chamber, with the more evolved lower Caetano Tuff consisting of extracted liquids that continued to crystallize and mix in the upper part of the chamber following segregation from a cumulate-rich, and more heterogeneous, source mush. The latter is represented in the caldera stratigraphy by the less evolved upper Caetano Tuff. Whole-rock major, trace and rare earth element geochemistry, modal mineralogy and mineral chemistry, O, Sr, Nd and Pb isotope geochemistry, sanidine Ar–Ar geochronology, and zircon U–Pb geochronology and trace element geochemistry provide robust evidence that the voluminous caldera intrusions (Carico Lake pluton and Redrock Canyon porphyry) are genetically equivalent to the least evolved Caetano Tuff and formed from magma that remained in the lower chamber after

Probing the volcanic-plutonic connection and the genesis of crystal-rich rhyolite in a deeply dissected supervolcano in the Nevada Great Basin: Source of the late Eocene Caetano Tuff

Science.gov (United States)

Watts, Kathryn E.; John, David A.; Colgan, Joseph P.; Henry, Christopher D.; Bindeman, Ilya N.; Schmitt, Axel K.

2016-01-01

Late Cenozoic faulting and large-magnitude extension in the Great Basin of the western USA has created locally deep windows into the upper crust, permitting direct study of volcanic and plutonic rocks within individual calderas. The Caetano caldera in north–central Nevada, formed during the mid-Tertiary ignimbrite flare-up, offers one of the best exposed and most complete records of caldera magmatism. Integrating whole-rock geochemistry, mineral chemistry, isotope geochemistry and geochronology with field studies and geologic mapping, we define the petrologic evolution of the magmatic system that sourced the >1100 km3Caetano Tuff. The intra-caldera Caetano Tuff is up to ∼5 km thick, composed of crystal-rich (30–45 vol. %), high-silica rhyolite, overlain by a smaller volume of comparably crystal-rich, low-silica rhyolite. It defies classification as either a monotonous intermediate or crystal-poor zoned rhyolite, as commonly ascribed to ignimbrite eruptions. Crystallization modeling based on the observed mineralogy and major and trace element geochemistry demonstrates that the compositional zonation can be explained by liquid–cumulate evolution in the Caetano Tuff magma chamber, with the more evolved lower Caetano Tuff consisting of extracted liquids that continued to crystallize and mix in the upper part of the chamber following segregation from a cumulate-rich, and more heterogeneous, source mush. The latter is represented in the caldera stratigraphy by the less evolved upper Caetano Tuff. Whole-rock major, trace and rare earth element geochemistry, modal mineralogy and mineral chemistry, O, Sr, Nd and Pb isotope geochemistry, sanidine Ar–Ar geochronology, and zircon U–Pb geochronology and trace element geochemistry provide robust evidence that the voluminous caldera intrusions (Carico Lake pluton and Redrock Canyon porphyry) are genetically equivalent to the least evolved Caetano Tuff and formed from magma that remained in the lower chamber after

Study on the effect of Shahin-Dezh green Tuff on the mechanical characteristics of roller compact concrete

Directory of Open Access Journals (Sweden)

Sadegh Dardaei

2016-12-01

Full Text Available Due to the growing popularity of concrete structure and increasing use of them, especially Roller compacted concrete, applying Pozzolan and replacing cement with Pozzolan is very important. Nowadays, the use of the additive for cement replacement is common in RCC mix design due to its technical advantages and economic benefits as there is large quantity of Pozzolan mineral resources in Iran. In this paper the impact of produced concrete has been fully considered as well as the effect of this Pozzolan on the compressive strength, tensile strength and permeability by using green Tuff obtained from available Pozzolan in western Azarbaijan. The due results prove that Shahin-Dezh green Tuff improves concretes quality.

The man and the hill

Science.gov (United States)

Leopold, Luna Bergere

1962-01-01

He was sitting on a large slab of rock. As he looked at the cloud of dust hanging hazily on the horizon, the piece of antler and the block of flint he held in his hand hung as if they were suspended from their previous rapid motion. The man gazed intently across the swaying grass which rose in wave-like billows across the distant hills. What was that dust - a herd of buffalo, a band of hunters, or were coyotes chasing the antelope again? After watching for a while he started again to chip the flint with a rapid twisting motion of the bone in his right hand. The little chips of flint fell in the grass before him. It is the same hill but the scene has changed. Seated on the same rock, holding the reins of a saddle horse, a man dressed in buckskin took the fur cap off his head and wiped his brow. He was looking intently across a brown and desolate landscape at a cloud of dust on the far horizon. Was it the hostile tribe of Indians? It could be buffalo. Nervously he kicked at the ground with the deerhide moccasin, pushing the flint chips out of the way. He wiped the dust from his long rifle. What a terrible place - no water, practically no grass, everything bare and brown. Now at sunset, slanting across the hills green with springtime, a cowman sits on a big rock, pushes his sombrero back on his head, and looks across the valley at a large but quiet herd of stock, moving slowly as each steer walks from one lush patch of grass to another, nibbling. Suddenly he stood up. Far on the horizon some dark objects were moving. Is it the sheepmen? Could it be the stage coach from Baggs to the Sweetwater Crossing?Same hill - a gray truck was grinding slowly toward the summit. It pulled up near a small fenced enclosure where there were some instruments painted a bright silver color. A man stepped out of the truck and turned to his younger companion, "You've never found an arrowhead? Maybe you have never thought about it correctly. If you want to find where an Indian camped long

PHYSIOLOGICAL REACTION OF THE SPECIES BRASSICA JUNCEA (L. CZERN. ON SALINIZED SOILS AMELIORATED WITH ZEOLITIC TUFF, PEAT AND PERLITE

Directory of Open Access Journals (Sweden)

Maria Cătălina PASTIA

2017-12-01

Full Text Available The physiological reaction of saline stress which Brassica juncea (L. Czern. plants undergo shows a greater growth and fresh substance gain process on previously cultivated soils that were fined with 20% zeolitic tuff and 5.09 g of neutral peat than the ones that had a substrate which hasn’t been cultivated on before that was fined with 5% zeolitic tuff and 1.39 g of perlite. The dry substance values obtained present a positive correlation with the values of fresh substance. Analysis of stomatal conductance enhances the hydric stress of plants which respond to saline stress with osmotic adjustment, accumulating high quantities of water comparing to the witness plant, which induces lower values of stomatal conductance and implicitly values are decreasing for photosynthesis, determining a low productivity. Higher values of stomatal conductance are reached at plants grown on previously cultivated soils fined with 20% zeolitic tuff and peat, and also at the ones grown on uncultivated soils fined with peat (29.45, respectively 30.05 mmol/m2/s.

Containment barrier metals for high-level waste packages in a Tuff repository

International Nuclear Information System (INIS)

Russell, E.W.; McCright, R.D.; O'Neal, W.C.

1983-01-01

The Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package project is part of the US Department of Energy's Civilian Radioactive Waste Management (CRWM) Program. The NNWSI project is working towards the development of multibarriered packages for the disposal of spent fuel and high-level waste in tuff in the unsaturated zone at Yucca Mountain at the Nevada Test Site (NTS). The final engineered barrier system design may be composed of a waste form, canister, overpack, borehole liner, packing, and the near field host rock, or some combination thereof. Lawrence Livermore National Laboratory's (LLNL) role is to design, model, and test the waste package subsystem for the tuff repository. At the present stage of development of the nuclear waste management program at LLNL, the detailed requirements for the waste package design are not yet firmly established. In spite of these uncertainties as to the detailed package requirements, we have begun the conceptual design stage. By conceptual design, we mean design based on our best assessment of present and future regulatory requirements. We anticipate that changes will occur as the detailed requirements for waste package design are finalized. 17 references, 4 figures, 10 tables

Containment barrier metals for high-level waste packages in a Tuff repository

Energy Technology Data Exchange (ETDEWEB)

Russell, E.W.; McCright, R.D.; O`Neal, W.C.

1983-10-12

The Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package project is part of the US Department of Energy`s Civilian Radioactive Waste Management (CRWM) Program. The NNWSI project is working towards the development of multibarriered packages for the disposal of spent fuel and high-level waste in tuff in the unsaturated zone at Yucca Mountain at the Nevada Test Site (NTS). The final engineered barrier system design may be composed of a waste form, canister, overpack, borehole liner, packing, and the near field host rock, or some combination thereof. Lawrence Livermore National Laboratory`s (LLNL) role is to design, model, and test the waste package subsystem for the tuff repository. At the present stage of development of the nuclear waste management program at LLNL, the detailed requirements for the waste package design are not yet firmly established. In spite of these uncertainties as to the detailed package requirements, we have begun the conceptual design stage. By conceptual design, we mean design based on our best assessment of present and future regulatory requirements. We anticipate that changes will occur as the detailed requirements for waste package design are finalized. 17 references, 4 figures, 10 tables.

New fission-track ages of mio-pliocene tuffs in the Sierras Pampeanas and Precordillera of Argentina

International Nuclear Information System (INIS)

Tabbutt, K.; Naeser, C.W.; Jordan, T.E.; Cerveny, P.F.

1989-01-01

Fission-track dates were determined for 18 volcanic tuff horizons located in nine Neogene foreland basin sequences distributed throughout the Precordillera and Sierras Pampeanas of Northwestern Argentina, an area of nearly horizontal subduction. These and other data indicate that a lower age limit for the sedimentary sequences studied is approximately 17 Ma. Therefore these fission-track dates constrain both the history of volcanic activity and the time of deposition in several foreland basins from the middle Miocene to Recent. Although the dates range from 3.6±0.8 Ma to 17.0±1.9 Ma, there is a marked increase in the number of ashes younger than 9 Ma. This implies that two distinct episodes of volcanic activity affected the region. The source of some of these tuffs is unknown but they are probably limited to the 'flat-slab' region between 27 deg and 32 deg S. Tuffs at Rio Blanco and Santa Florentina that are spatially associated with the Mogotes dacite domes of the Famatina Range represented magmatism bracketed from about 7 to 4 Ma in the region underlain by the flat-subducted plate. The stratigraphic relations in the basins show that the faulting that uplifted Sierra de Famatina was contemporaneous with the volcanism which reached the surface along the bounding faults. (Author) [es

Estimation of possibilities of making euro pallets from reclaimed polyolefin’s with tuff

Directory of Open Access Journals (Sweden)

S. Kuciel

2010-07-01

Full Text Available Possibilities of reusing and developing of waste plastics are one of the main problems of waste management for municipal governmentespecially in the context of adapting Polish law to standards of EC [1]. During the last 10 years total amount of plastics waste increasedtwice, especially in communal agglomerations. Among communal waste plastics make up 7 to 14% of whole their mass and 30% of theirvolume [1,2]. Plastic products have been recycled to be used in a number of different products often different from their original use.Reclaimed plastics can’t be used as products which have contact with food or as high demands esthetic and hygienic products, they alsoshouldn’t be applied as short-time used products because they quickly come back to plastics store-place. Reclaimed plastics have lowerproperties than virgin plastics – mainly the strength falls with the simultaneous fall of modules and increase fragile especially for PP, PE,PS and PET [1]. One of the possibilities of reinforcement of polyolefines is adding diverse fillers like glass or carbon fibers (but they arerather expensive and natural fillers like mineral, wood and others [3]. It’s especially important for wasted of low density polyethylenewhich has low modulus. For the tests it was used waste polyethylene (LDPE and HDPE from industrial with 15% mineral fillers – tuff.For the tests it was prepared two kinds of composites materials with 15% of tuff powder. Besides for comparison it was tested recycledpolyethylene (HDPE and LDPE and next was tested specimens cut out from produced europallets (with 15% of tuff. It was testedmechanical properties all prepared composite materials like tensile strength, stress and bending e-modulus and processing properties likemelt flow, Vicat point and photos on SEM microscope.

Radionuclide transfer onto ground surface in surface water flow. 2. Undisturbed tuff rock

International Nuclear Information System (INIS)

Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu

1994-09-01

Radionuclide migration with ground surface water flow is considered to be one of path ways in the scenario for environmental migration of the radionuclide leaked from LLRW depository. To study the radionuclide migration demonstratively, a ground surface radionuclide migration test was carried out by simulating radioactive solution flowing on the sloped tuff rock surface. Tuff rock sample of 240 cm in length taken from the Shimokita district was used to test the transfer of 60 Co, 85 Sr and 137 Cs onto the sample surface from the flowing radioactive solution under restricted infiltration condition at flow rates of 25, 80, 160ml/min and duration of 56h. The concentration change of the radionuclides in effluent was nearly constant as a function of elapsed time during the experimental period, but decreased with lower flow rates. Among the three radionuclides, 137 Cs was greatly decreased its concentration to 30% of the inflow. Adsorbed distribution of the radionuclides concentration on the ground surface decreased gradually with the distance from the inlet, and showed greater gradient at lower flow rate. Analyzing the result by the migration model, where a vertical advection distribution and two-dimensional diffusion in surface water are adopted with a first order adsorption reaction, value of migration parameters was obtained relating to the radionuclide adsorption and the surface water flow, and the measured distribution could be well simulated by adopting the value to the model. By comparing the values with the case of loamy soil layer, all values of the migration parameters showed not so great difference between two samples for 60 Co and 85 Sr. For 137 Cs, reflecting a few larger value of adsorption to the tuff rock, larger ability to reduce the concentration of flowing radioactive solution could be indicated than that to the loamy soil surface by estimation for long flowed distance. (author)

Construction of the North Head (Maungauika) tuff cone: a product of Surtseyan volcanism, rare in the Auckland Volcanic Field, New Zealand

Science.gov (United States)

Agustín-Flores, Javier; Németh, Károly; Cronin, Shane J.; Lindsay, Jan M.; Kereszturi, Gábor

2015-02-01

The Auckland Volcanic Field (AVF) comprises at least 52 monogenetic eruption centres dispersed over ˜360 km2. Eruptions have occurred sporadically since 250 ka, predominantly when glacio-eustatic sea levels were lower than today. Now that around 35 % of the field is covered by shallow water (up to 30 m depth), any eruption occurring in the present or near future within this area may display Surtseyan dynamics. The North Head tuff cone evidences eruptive dynamics caused by magma interaction with seawater. The first stages of the eruption comprise a phreatomagmatic phase that built a 48-m-high tuff cone. North Head tuff deposits contain few lithic fragments (Auckland area was at least 10-12 m above the pre-eruptive surface. The hazards associated with this type of eruption pose a risk to the densely populated coastal residential zones and the activities of one of the busiest harbours in New Zealand.

Removal and recovery of p-phenylenediamines developing compounds from photofinishing lab-washwater using clinoptilolite tuffs from Greece.

Science.gov (United States)

Vlessidis, A G; Triantafillidis, C S; Evmiridis, N P

2001-04-01

Clinoptilolite tuffs from areas in Thrace region of Greece are compared with synthetic zeolites NaY and NH4Y for the uptake of N4-ethyl-N4-(2-methansulphonamidoethyl)-2-methyl-1,4-phenylenediamin (sesquisulphate, monohydrate) with the trade name CD-3 for the purpose to be used for clean-up and recycling photo-finishing and photo-developing washwaters. The cation-exchange capacity is found to be 6.15-11.1 mg/g for zeoliferous tuffs at equilibrium concentration of 50 ppm CD-3 in aqueous solution compared to 65.0 mg/g of NaY and 48.2 mg/g for NH4Y synthetic zeolites corresponding to the removal of CD-3 from 120 to 2001 of 50 ppm aqueous solution per kg of natural zeoliferous tuff; this capacity is only 6-10 times lower than type-Y synthetic zeolite. Initial rates of uptake are 20.8 mg/l/min for natural and 38.5 mg/l/min for synthetic zeolites. Regeneration levels of 55, 23, 35, and 33% are obtained for MCH, SF, NaY, and NH4Y, respectively. The rapid and almost complete uptake of CD-3 from its aqueous solutions at low CD-3 concentrations by the natural zeolites is promising for such an application.

Geohydrology of volcanic tuff penetrated by test well UE-25b#1, Yucca Mountain, Nye County, Nevada

Science.gov (United States)

Lahoud, R.G.; Lobmeyer, D.H.; Whitfield, M.S.

1984-01-01

Test well UE-25bNo1, located on the east side of Yucca Mountain in the southwestern part of the Nevada Test Site, was drilled to a total depth of 1,220 meters and hydraulically tested as part of a program to evaluate the suitability of Yucca Mountain as a nuclear-waste repository. The well penetrated almost 46 meters of alluvium and 1,174 meters of Tertiary volcanic tuffs. The composite hydraulic head for aquifers penetrated by the well was 728.9 meters above sea level (471.4 meters below land surface) with a slight decrease in loss of hydraulic head with depth. Average hydraulic conductivities for stratigraphic units determined from pumping tests, borehole-flow surveys, and packer-injection tests ranged from less than 0.001 meter per day for the Tram Member of the Crater Flat Tuff to 1.1 meters per day for the Bullfrog Member of the Crater Flat Tuff. The small values represented matrix permeability of unfractured rock; the large values probably resulted from fracture permeability. Chemical analyses indicated that the water is a soft sodium bicarbonate type, slightly alkaline, with large concentrations of dissolved silica and sulfate. Uncorrected carbon-14 age dates of the water were 14,100 and 13,400 years. (USGS)

Measurement of unsaturated hydraulic conductivity and chemical transport in Yucca Mountain Tuff: Milestone Report 3044-WBS1.2.3.4.1.4.1

International Nuclear Information System (INIS)

Conca, J.L.

1993-12-01

Hydraulic conductivities, K, were experimentally determined as a function of volumetric water content, θ, in tuff from the Yucca Mountain site. In addition, the retardation factor, R f , in Yucca Mountain tuff with respect to selenium, as the selenite species, was measured under unsaturated conditions. These data were used to determine the feasibility of applying a new unsaturated flow technology (UFA) to further hydrologic studies at Yucca Mountain. The UFA directly measures K(θ) rapidly in Yucca Mountain tuff and is shown to agree well with traditional methods. Hysteresis does not appear important during this testing. Hydraulic steady-state is achieved fastest during desaturation from a saturated state. Imbibition into dry tuff requires a long time for steady-state to occur because of slow filling of the diffusion porosity which can take a few weeks. The existing UFA is a prototype, and a new design of the next generation UFA is completed that eliminates some of the earlier problems. These preliminary investigations demonstrates that the UFA is a useful investigate technique that should be used to compliment existing techniques for hydrogeochemical characterization at Yucca Mountain and other arid sites

Radionuclide transport and retardation in tuff

International Nuclear Information System (INIS)

Vine, E.N.; Bayhurst, B.P.; Daniels, W.R.; DeVilliers, S.J.; Erdal, B.R.; Lawrence, F.O.; Wolfsberg, K.

1980-01-01

Batch measurements provide an understanding of which experimental variables are important. For example, sorption ratios vary little with particle size (and surface area); however, groundwater composition and rock composition are quite important. A general correlation has been identified between mineralogy (major phases) and degree of sorption for strontium, cesium, and barium. Although these are approximate, a more detailed analysis may be possible as more samples are studied and the data base increased. Data from crushed tuff columns indicate that, except in simple cases where sorption coefficients are relatively low, and ion-exchange equilibria not only exist but are the dominant mechanism for removal of radioisotopes from solution, the simple relation between the sorption ratio R/sub d/ (or K/sub d/) and the relative velocity of radionuclides with respect to groundwater velocity may be insufficient to permit accurate modeling of the retardation of radionuclides. Additional work on whole core columns and larger blocks of intact material is required to better understand radionuclide sorption and transport through rock

Sorption-desorption studies on tuff III. A continuation of studies with samples from Jackass Flats and Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Wolfsberg, K.; Aguilar, R.D.; Bayhurst, B.P.

1981-05-01

This report is the third in a series of reports describing studies of sorption and migration of radionuclides in tuff. The investigations were extended to lithologies of tuff not previously studied. Continuing experiments with uranium, plutonium, and americium are described. The dependence of sorption on the concentration of the sorbing element and on the solution-to-solid ratio was investigated for a number of nuclides and two lithologies. A circulating system was designed for measuring sorption ratios. Values obtained from this system, batch measurements, and column elutions are compared. Progress on measuring and controlling Eh is described

Alteration history studies in the Exploratory Studies Facility, Yucca Mountain, Nevada, USA

International Nuclear Information System (INIS)

Levy, S.S.; Chipera, S.J.; Norman, D.I.

1996-01-01

By mid-1995, the Exploratory Studies Facility (ESF) extended about 1. 1 km from Exile Hill westward toward Yucca Mountain, mostly within densely welded, devitrfied Tiva Canyon Tuff. Secondary mineral occurrences in this unit include breccia cements of mordenite, a fibrous zeolite, and vapor-phase deposits of silica, alkali feldspar, apatite, hollandite, amphibole, and zircon. Calcite is also a common secondary mineral in faults and fractures. Studies of water and gas contents in fluid inclusions in calcites from a fault in nonwelded tuff and a fracture in densely welded tuff suggest mineral deposition under transient locally saturated conditions. Calcite in the nonwelded tuff incorporated air from the unsaturated tuff adjacent to the fault. A highly altered interval within pre-Pah Canyon tuffs just above the top of the Topopah Spring Tuff may be a fossil fumarole or other hydrothermal feature associated with cooling pyroclastic deposits, overprinted by later zeolitic alteration. The observed quartz, cristobalite, opal-CT, and fluorite have been widely identified as products of syngenetic devitrification and vapor-phase alteration in and above the Topopah Spring Tuff. Smectite, also an abundant secondary mineral at the ESF site, has been observed elsewhere at this stratigraphic level. Zeolitic alteration of nonwelded tuffs above the Topopah Spring Tuff, as seen in the ESF, has also been noted in drill core and outcrop at northeastern Yucca Mountain. The hydrologic and geochemical conditions that favored zeolitization only in certain areas of this stratigraphic interval have yet to be determined

Penyelesaian Masalah 8-Puzzle dengan Algoritma Steepest-Ascent Hill Climbing

Directory of Open Access Journals (Sweden)

David Abraham

2016-03-01

Full Text Available 8 puzzle merupakan salah satu implementasi dari Artificial Intelegence. Dalam proses penyelesaiannya banyak terdapat algoritma-algoritma pencarian yang dapat diterapkan. Solusi 8 puzzle akan lebih cepat diperoleh jika digunakan prinsip array dengan variasi algoritma Steepest-Ascent Hill Climbing (Hill Climbing dengan memilih kemiringan yang paling tajam / curam dengan parameter heuristik posisi yang benar dan heuristik jarak serta dikombinasikan dengan LogList sebagai penyimpanan state state yang pernah dilalui untuk menanggulangi permasalah pada algoritma hill climbing itu sendiri dan terhindar dari looping state yang pernah dilalui. Metode-metode yang termasuk ke dalam teknik pencarian yang berdasarkan pada fungsi heuristik salah satu diantaranya adalah Hill Climbing, Best First Search, A* (A Bintang. Loglist merupakan tempat penyimpanan setiap kunjungan dari state-state puzzle yang telah dilakukan untuk menghindari looping atau pengulangan terhadap state yang pernah dilalui. Untuk menanggulangi permasalahan pada SteepestAscent Hill Climbing.

Occurrence of rhyolytic tuffs at deep sea drilling project site 219 on the Laccadive Ridge

Digital Repository Service at National Institute of Oceanography (India)

Siddiquie, H.N.; Sukheswala, R.N.

A study of thin sections from the lower and middle parts of Unit 5 (Paleocene) from Site 219 shows that these largely consist of acidic or rhyolitic tuffs. The overlying limestones in Unit 5 (Paleocene) and Unit 4 (Lower Eocene) also contain...

Newtonian and pseudo-Newtonian Hill problem

International Nuclear Information System (INIS)

Steklain, A.F.; Letelier, P.S.

2006-01-01

A pseudo-Newtonian Hill problem based on the Paczynski-Wiita pseudo-Newtonian potential that reproduces general relativistic effects is presented and compared with the usual Newtonian Hill problem. Poincare maps, Lyapunov exponents and fractal escape techniques are employed to study bounded and unbounded orbits. In particular we consider the systems composed by Sun, Earth and Moon and composed by the Milky Way, the M2 cluster and a star. We find that some pseudo-Newtonian systems-including the M2 system-are more stable than their Newtonian equivalent

Spectral parameter power series representation for Hill's discriminant

International Nuclear Information System (INIS)

Khmelnytskaya, K.V.; Rosu, H.C.

2010-01-01

We establish a series representation of the Hill discriminant based on the spectral parameter power series (SPPS) recently introduced by Kravchenko. We also show the invariance of the Hill discriminant under a Darboux transformation and employing the Mathieu case the feasibility of this type of series for numerical calculations of the eigenspectrum.

Plants profile of Malakand Pass Hills, District Malakand, Pakistan

African Journals Online (AJOL)

use

2011-11-21

Nov 21, 2011 ... famous Malakand fort guards the road on both sides of the pass. Malakand is a ... Underneath Malakand Hills, the waters of the River Swat ... southern sloping faces of the hills. They speak ...... Pinus roxburghii Sarg. Antidote ...

Characterization of crushed tuff for the evaluation of the fate of tracers in transport studies in the unsaturated zone

International Nuclear Information System (INIS)

Polzer, W.L.; Fuentes, H.R.; Raymond, R.; Bish, D.L.; Gladney, E.S.; Lopez, E.A.

1987-03-01

Results of field-scale (caisson) transport studies under unsaturated moisture and steady and nonsteady flow conditions indicate variability and a lack of conservation of mass in solute transport. The tuff materials used in that study were analyzed for the presence of tracers and of freshly precipitated material to help explain the variability and lack of conservation of mass. Selected tuff samples were characterized by neutron activation analysis for tracer identification, by x-ray diffraction for mineral identification, by petrographic analysis for identification of freshly precipitated material, and by x-ray fluorescence analysis for identification of major and trace elements. The results of these analyses indicate no obvious presence of freshly precipitated material that would retard tracer movement. The presence of the nonsorbing tracers (bromide and iodide) suggest the retention of these tracers in immobile water. The presence of the nonsorbing tracers (bromide and iodide) suggest the retention of these tracers in immobile water. The presence of sorbing and nonsorbing tracers on the tuff at some locations (even cesium at the 415-cm depth) and not at others suggests variability in transport. 15 refs., 14 figs., 9 tabs

Experimental investigation of flow over two-dimensional multiple hill models.

Science.gov (United States)

Li, Qing'an; Maeda, Takao; Kamada, Yasunari; Yamada, Keisuke

2017-12-31

The aim of this study is to investigate the flow field characteristics in ABL (Atmospheric Boundary Layer) flow over multiple hills and valleys in two-dimensional models under neutral conditions. Active turbulence grids and boundary layer generation frame were used to simulate the natural winds in wind tunnel experiments. As a result, the mean wind velocity, the velocity vector diagram and turbulence intensity around the hills were investigated by using a PIV (Particle Image Velocimetry) system. From the measurement results, it was known that the average velocity was increased along the upstream slope of upside hill, and then separated at the top of the hills, the acceleration region of U/U ref >1 was generated at the downstream of the hill. Meanwhile, a large clockwise circulation flow was generated between the two hill models. Moreover, the turbulence intensity showed small value in the circulation flow regions. Compared to 1H model, the turbulence intensity in the mainstream direction showed larger value than that in the vertical direction. This paper provided a better understanding of the wind energy distribution on the terrain for proper selection of suitable sites for installing wind farms in the ABL. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical simulation of air- and water-flow experiments in a block of variably saturated, fractured tuff from Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Kwicklis, E.M.; Healy, R.W.; Thamir, F.; Hampson, D.

1998-01-01

Numerical models of water movement through variably saturated, fractured tuff have undergone little testing against experimental data collected from relatively well-controlled and characterized experiments. This report used the results of a multistage experiment on a block of variably saturated, fractured, welded tuff and associated core samples to investigate if those results could be explained using models and concepts currently used to simulate water movement in variably saturated, fractured tuff at Yucca Mountain, Nevada, the potential location of a high-level nuclear-waste repository. Aspects of the experiment were modeled with varying degrees of success. Imbibition experiments performed on cores of various lengths and diameters were adequately described by models using independently measured permeabilities and moisture-characteristic curves, provided that permeability reductions resulting from the presence of entrapped air were considered. Entrapped gas limited maximum water saturations during imbibition to approximately 0.70 to 0,80 of the fillable porosity values determined by vacuum saturation. A numerical simulator developed for application to fluid flow problems in fracture networks was used to analyze the results of air-injection tests conducted within the tuff block through 1.25-cm-diameter boreholes. These analyses produced estimates of transmissivity for selected fractures within the block. Transmissivities of other fractures were assigned on the basis of visual similarity to one of the tested fractures. The calibrated model explained 53% of the observed pressure variance at the monitoring boreholes (with the results for six outliers omitted) and 97% of the overall pressure variance (including monitoring and injection boreholes) in the subset of air-injection tests examined

Selection of candidate canister materials for high-level nuclear waste containment in a tuff repository

International Nuclear Information System (INIS)

McCright, R.D.; Weiss, H.; Juhas, M.C.; Logan, R.W.

1983-11-01

A repository located at Yucca Mountain at the Nevada Test Site is a potential site for permanent geological disposal of high-level nuclear waste. The repository can be located in a horizon in welded tuff, a volcanic rock, which is above the static water level at this site. The environmental conditions in this unsaturated zone are expected to be air and water vapor dominated for much of the containment period. Type 304L stainless steel is the reference material for fabricating canisters to contain the solid high-level wastes. Alternative stainless alloys are considered because of possible susceptibility of 304L to localized and stress forms of corrosion. For the reprocessed glass wastes, the canisters serve as the recipient for pouring the glass with the result that a sensitized microstructure may develop because of the times at elevated temperatures. Corrosion testing of the reference and alternative materials has begun in tuff-conditioned water and steam environments. 21 references, 8 figures, 8 tables

Clinoptilolite compositions in diagenetically-altered tuffs at a potential nuclear waste repository, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Broxton, D.E.

1987-01-01

The compositions of Yucca Mountain clinoptilolites and their host tuffs are highly variable. Clinoptilolites and heulandites in fractures near the repository and in a thin, altered zone at the top of the Topopah Spring basal vitrophyre have consistent calcium-rich compositions. Below this level, clinoptilolites in thick zones of diagenetic alteration on the east side of Yucca Mountain have calcic-potassic compositions and become more calcium rich with depth. Clinoptilolites in stratigraphically equivalent tuffs to the west have sodic-potassic compositions and become more sodic with depth. Clinoptilolite properties important for repository performance assessment include thermal expansion/contraction behavior, hydration/dehydration behavior, and ion-exchange properties. These properties can be significantly affected by clinoptilolite compositions. The compositional variations for clinoptilolites found by this study suggest that the properties will vary vertically and laterally at Yucca Mountain. Used in conjunction with experimental data, the clinoptilolite compositions presented here can be used to model the behavior of clinoptilolites in the repository environment and along transport pathways

Phosphorus forms in soils of Oban Hills, Akamkpa, Cross River State ...

African Journals Online (AJOL)

Oban Hills is located at Akamkpa in the Southern Senatorial District of Cross River, State, Nigeria. Phosphorus (P)-rich soil from the Hills is expected to have an effect on retention and distribution in the highly acidic soils surrounding the area inundated for several years. Phosphorus forms in the soils of the Hills varied with ...

Photovoltaics - 10 years after Cherry Hill

Science.gov (United States)

Ralph, E. L.

The status of R&D programs connected with photovoltaic (PV) systems 10 years after the Cherry Hill workshop on 'Photovoltaic Conversion of Solar Energy for Terrestrial Applications' is assessed. The five categories of research recommended by the Cherry Hill Workshop are listed in a table together with their recommended research budget allocations. The workshop categories include: single-crystal Si cells; poly-Si cells; systems and diagnostics. Categories for thin film CdS/Cu2S and CuInSe2 cells are also included. The roles of government and private utility companies in providing adequate financial support for PV research programs is emphasized.

Maximum likelihood Bayesian averaging of airflow models in unsaturated fractured tuff using Occam and variance windows

NARCIS (Netherlands)

Morales-Casique, E.; Neuman, S.P.; Vesselinov, V.V.

2010-01-01

We use log permeability and porosity data obtained from single-hole pneumatic packer tests in six boreholes drilled into unsaturated fractured tuff near Superior, Arizona, to postulate, calibrate and compare five alternative variogram models (exponential, exponential with linear drift, power,

78 FR 73187 - Black Hills National Forest Advisory Board

Science.gov (United States)

2013-12-05

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board... all members of the Advisory Board; (2) provide orientation to Board Members on Basic Laws governing...

Funny hills in pion spectra from heavy-ion collisions

International Nuclear Information System (INIS)

Rasmussen, J.O.

1982-03-01

A discussion of some of the systematic features of the pion spectra in heavy-ions reactions is given. A discussion of the hills and valleys in heavy ion pion spectra that show up at the lower pion energies is given. The following topics are discussed: (1) three kinds of funny hills; (2) π - / + ratios near center of mass; (3) new Monte Carlo studies of charged pion spectra; and (4) pion orbiting about fireballs and Bose-Einstein behavior as explanation for the mid-rapidity P/sub perpendicular to/ approx. = 0.4 to 0.5 m/sub π/c hill

Photon Shielding Features of Quarry Tuff

Directory of Open Access Journals (Sweden)

Vega-Carrillo Hector Rene

2017-01-01

Full Text Available Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl-based γ-ray spectrometer and a 137Cs source.

Effects of long-term exposure of tuffs to high-level nuclear waste-repository conditions. Preliminary report

International Nuclear Information System (INIS)

Blacic, J.; Carter, J.; Halleck, P.; Johnson, P.; Shankland, T.; Andersen, R.; Spicochi, K.; Heller, A.

1982-02-01

Tests have been performed to explore the effects of extended exposure of tuffs from the southwestern portion of the Nevada Test Site to temperatures and pressures similar to those that will be encountered in a high-level nuclear waste repository. Tuff samples ranging from highly welded, nonzeolitized to unwelded, highly zeolitized varieties were subjected to temperatures of 80, 120, and 180 0 C; confining pressures of 9.7 and 19.7 MPa; and water-pore pressures of 0.5 to 19.7 MPa for durations of 2 to 6 months. The following basic properties were measured before and after exposure and compared: tensile strength, uniaxial compressive strength, grain density, porosity, mineralogy, permeability, thermal expansion, and thermal conductivity. Depending on rock type and exposure conditions, significant changes in ambient tensile strength, compressive strength, grain density, and porosity were measured. Mineralogic examination, permeability, and thermal property measurements remain to be completed

EMG activities and plantar pressures during ski jumping take-off on three different sized hills.

Science.gov (United States)

Virmavirta, M; Perttunen, J; Komi, P V

2001-04-01

Different profiles of ski jumping hills have been assumed to make the initiation of take-off difficult especially when moving from one hill to another. Neuromuscular adaptation of ski jumpers to the different jumping hills was examined by measuring muscle activation and plantar pressure of the primary take-off muscles on three different sized hills. Two young ski jumpers volunteered as subjects and they performed several trials from each hill (K-35 m, K-65 m and K-90 m) with the same electromyographic (EMG) electrode and insole pressure transducer set-up. The results showed that the differences in plantar pressure and EMGs between the jumping hills were smaller than expected for both jumpers. The small changes in EMG amplitudes between the hills support the assumption that the take-off was performed with the same intensity on different jumping hills and the timing of the gluteus EMG demonstrates well the similarity of the muscle activation on different hills. On the basis of the results obtained it seems that ski jumping training on small hills does not disturb the movement patterns for bigger hills and can also be helpful for special take-off training with low speed.

Ages of tuff beds at East African early hominid sites and sediments in the Gulf of Aden

Science.gov (United States)

Sarna-Wojcicki, A. M.; Meyer, C.E.; Roth, P.H.; Brown, F.H.

1985-01-01

The early hominids of East Africa were dated by determining the ages of tuff beds at the sites. Despite much research using palaeomagnetic and K/Ar-dating techniques, some of those ages are still controversial 1,2. To obtain independent age estimates for these tephra layers, we have examined cores from DSDP Sites 231 and 232 in the Gulf of Aden (Fig. 1a) which consist mainly of calcareous nannofossil ooze, but also contain rare tephra horizons3 dated by interpolation from the established nannofossil stratigraphy (Fig. 1b). Chemical analysis confirms that the identity and sequence of these horizons is the same as that at the East African sites. We conclude that the age of the Tulu Bor Tuff is <3.4 Myr and hence that the Hadar hominid specimens are also

Gas phase migration of C-14 through barrier materials applicable for use in a high-level nuclear waste repository located in tuff

International Nuclear Information System (INIS)

Bauer, L.R.

1988-12-01

A study of the movement of 14 CO 2 through proposed barrier media has been conducted. Diffusion coefficients for crushed tuff, bentonite and a 90:10% by wt. mixture of crushed tuff and bentonite were measured for two diffusion lengths. The ability of 14 CO 2 to penetrate a microsilica-containing portland cement mortar proposed for repository use was also examined. The specimens were subjected to uniaxially-applied compressive loads prior to the diffusion tests to simulate the onset of environmentally-induced microcracks. 91 refs., 14 figs., 15 tabs

Preliminary design and definition of field experiments for welded tuff rock mechanics program

International Nuclear Information System (INIS)

Zimmerman, R.M.

1982-06-01

The preliminary design contains objectives, typical experiment layouts, definitions of equipment and instrumentation, test matrices, preliminary design predictive modeling results for five experiments, and a definition of the G-Tunnel Underground Facility (GTUF) at the Nevada Test Site where the experiments are to be located. Experiments described for investigations in welded tuff are the Small Diameter Heater, Unit Cell-Canister Scale, Heated Block, Rocha Slot, and Miniature Heater

Measurements of distribution coefficient for Sn, Pb and Th on sand stone and tuff in saline type groundwater

International Nuclear Information System (INIS)

Nakazawa, Toshiyuki; Okada, Kenichi; Muroi, Masayuki; Shibata, Masahiro; Sasamoto, Hiroshi

2004-02-01

Japan Nuclear Cycle Development Institute (JNC) has developed the sorption database for bentonite and rocks in order to assess the retardation capacities of important radioactive elements in natural and engineered barriers in the H12 report. However, there are not enough distribution coefficient data for radioactive elements in saline type groundwater in the database. Sn (tin), Pb (lead) and Th(thorium) are important radioactive elements for performance assessment of high level radioactive waste disposal, thus we carried out the batch sorption experiments for these radioactive elements on sand stone and tuff. The experiments for each radioactive element were performed on the following conditions; Sn: Kd measurements using the solutions (distilled water or artificial sea water) reacted with sand stone. Pb: Kd measurements using solution (artificial sea water) reacted with sand stone or tuff. Th: Kd measurements using solution (artificial sea water) reacted with sand stone as a function of carbonate concentration. The results of experiment are summarized below; In the case of Sn, Kd were 0.4-1 m 3 /kg in distilled water type and approximately 1 m 3 /kg in artificial sea water type. And also, Kd was 0.3 m 3 /kg in artificial sea water adjusted Ph 12. In artificial sea water type, it was suggested that Kd decreased with pH. In the case of Pb, Kd were approximately 2 m 3 /kg on sand stone and 4-10 m 3 /kg on tuff in artificial sea water type. Kd on tuff was a little larger than that on sand stone. There were no distinctly differences depending on solid-liquid separation methods. In the case of Th, Kd was approximately 1-8 m 3 /kg in artificial sea water type. On the other hand, sorption of Th on sand stone was not observed (i.e., Kd = 0 m 3 /kg) in high carbonate solution. It was estimated that low Kd in high carbonate solution might be caused by speciation of because Th could form the anions in the solution such as hydroxo-carbonate complexes and carbonate complexes

Technology teachers as researchers : philosophical and empirical technology education studies in the Swedish TUFF Research School

NARCIS (Netherlands)

Skogh, I.B.; Vries, de M.J.

2013-01-01

This book presents the scientific output of the TUFF research school in Sweden. In this school, a group of active teachers worked together on a series of educational research studies. All of those studies were related to the teaching about technology and engineering. The research program consisted

Hill, Prof. Archibald Vivian

Indian Academy of Sciences (India)

Home; Fellowship. Fellow Profile. Elected: 1935 Honorary. Hill, Prof. Archibald Vivian Nobel Laureate (Medicine) - 1922. Date of birth: 26 September 1886. Date of death: 3 June 1977. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 January 2018. The 29th Mid-year ...

The montane forest associated amphibian species of the Taita Hills ...

African Journals Online (AJOL)

The montane forest associated amphibian species of the Taita Hills, Kenya. ... They are surrounded by the dry Tsavo plains. ... The biodiversity importance of the Taita Hills lies with the number of endemics per unit of area of remaining forest, ...

Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions

International Nuclear Information System (INIS)

Juhas, M.C.; McCright, R.D.; Garrison, R.E.

1984-11-01

This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain rate tests, and bent beam stress corrosion tests. Results indicate that Type 304L stainless steel shows excellent resistance to general, localized, and stress corrosion under the environmental and microstructural conditions tested so far. The environmental test conditions are 50 to 100 0 C J-13 well water (non-saline, near neutral pH, and oxic in nature) and saturated steam at 100 0 C. Microstructural conditions include solution annealed and long furnace heat treatments to provoke a sensitized structure. However, this particular type of stainless steel may be susceptible to long-term, low-temperature sensitization because of the combination of expected time at elevated temperature and residual stress in the container after emplacement in the repository. Other grades of austenitic stainless steels are reported to be more resistant to low-temperature sensitization. Future work will therefore include more extensive testing of these grades. 15 references, 5 figures, 7 tables

Are hills like white elephants?

Directory of Open Access Journals (Sweden)

Sunil Sharma

2016-11-01

Full Text Available 'Are Hills Like White Elephants?' is, of course, inspired by Hemingway; the tribute reflects on the abiding relevance of serious art in a changed world and extends the boundaries of his message to other human situations.

Late Devonian spermatophyte diversity and paleoecology at Red Hill, north-central Pennsylvania, USA

Energy Technology Data Exchange (ETDEWEB)

Cressler, Walter L. III. [Francis Harvey Green Library, 29 West Rosedale Avenue, West Chester University, West Chester, PA, 19383 (United States); Prestianni, Cyrille [Universite de Liege, Boulevard du Rectorat B18, Liege 4000 (Belgium); LePage, Ben A. [The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103 and PECO Energy Company, 2301 Market Avenue, S9-1, Philadelphia, PA 19103 (United States)

2010-08-01

Early spermatophytes have been discovered at Red Hill, a Late Devonian (Famennian) fossil locality in north-central Pennsylvania, USA. The Red Hill locality contains an Archaeopteris-dominated flora within an outcrop of the Duncannon Member of the Catskill Formation. Palynological analyses of the plant fossil-bearing horizons within the Red Hill outcrop indicate deposition within the VCo palynozone. This is the earliest time horizon known to contain evidence for spermatophytes, and is contemporaneous with well-known spermatophyte-bearing deposits in West Virginia and Belgium. Some of the spermatophyte material from Red Hill compares well with Aglosperma sp., previously known as isolated ovules from the latest Devonian of South Wales and England, thus extending its geographic and stratigraphic range. Red Hill specimens of Aglosperma sp. occur both as isolated ovules and attached to dichotomously forking axes. Additional spermatophyte cupules discovered at Red Hill are morphologically similar to those of the previously described Late Devonian spermatophytes Elkinsia Rothwell, Scheckler, et Gillespie, Moresnetia Stockmans, and Xenotheca Arber et Goode. Some of the Red Hill cupule complexes are distinct from the aforementioned taxa in consisting of slender dichotomously forking axes terminating in paired cupules with highly fused and symmetric cupule quadrant lobes. The distinctive nature of these Red Hill specimens warrants the creation of Duodimidia pfefferkornii Cressler, Prestianni, et LePage gen. et sp. nov. Plant fossil remains with sphenopteroid foliage are also present at Red Hill, possibly attributable to the spermatophytes. Previous systematic sampling of the rich plant-fossil bearing layer at Red Hill and analysis of its floristic diversity and abundance as well as the presence and absence of charcoal suggests a pattern of floral turnover from a local-scale Rhacophyton-dominated community to spermatophyte colonization following disturbance by wildfires

Numerical Simulation of Tuff Dissolution and Precipitation Experiments: Validation of Thermal-Hydrologic-Chemical (THC) Coupled-Process Modeling

Science.gov (United States)

Dobson, P. F.; Kneafsey, T. J.

2001-12-01

As part of an ongoing effort to evaluate THC effects on flow in fractured media, we performed a laboratory experiment and numerical simulations to investigate mineral dissolution and precipitation. To replicate mineral dissolution by condensate in fractured tuff, deionized water equilibrated with carbon dioxide was flowed for 1,500 hours through crushed Yucca Mountain tuff at 94° C. The reacted water was collected and sampled for major dissolved species, total alkalinity, electrical conductivity, and pH. The resulting steady-state fluid composition had a total dissolved solids content of about 140 mg/L; silica was the dominant dissolved constituent. A portion of the steady-state reacted water was flowed at 10.8 mL/hr into a 31.7-cm tall, 16.2-cm wide vertically oriented planar fracture with a hydraulic aperture of 31 microns in a block of welded Topopah Spring tuff that was maintained at 80° C at the top and 130° C at the bottom. The fracture began to seal within five days. A 1-D plug-flow model using the TOUGHREACT code developed at Berkeley Lab was used to simulate mineral dissolution, and a 2-D model was developed to simulate the flow of mineralized water through a planar fracture, where boiling conditions led to mineral precipitation. Predicted concentrations of the major dissolved constituents for the tuff dissolution were within a factor of 2 of the measured average steady-state compositions. The fracture-plugging simulations result in the precipitation of amorphous silica at the base of the boiling front, leading to a hundred-fold decrease in fracture permeability in less than 6 days, consistent with the laboratory experiment. These results help validate the use of the TOUGHREACT code for THC modeling of the Yucca Mountain system. The experiment and simulations indicate that boiling and concomitant precipitation of amorphous silica could cause significant reductions in fracture porosity and permeability on a local scale. The TOUGHREACT code will be used

Hydrogeology of the unsaturated zone, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Montazer, P.; Wilson, W.E.

1985-01-01

The unsaturated volcanic tuff beneath Yucca Mountain, Nevada, is being evaluated by the US Department of Energy as a host rock for a potential mined geologic repository for high-level radioactive waste. Assessment of site suitability needs an efficient and focused investigative program. A conceptual hydrogeologic model that simulates the flow of fluids through the unsaturated zone at Yucca Mountain was developed to guide the program and to provide a basis for preliminary assessment of site suitability. The study was made as part of the Nevada Nuclear Waste Storage Investigations Project of the US Department of Energy. Thickness of the unsaturated zone is about 1640 to 2460 feet (500 to 750 meters). Based on physical properties, the rocks in the unsaturated zone are grouped for the purpose of this paper into five informal hydrogeologic units. From top to bottom these units are: Tiva Canyon welded unit, Paintbrush nonwelded unit. Topopah Spring welded unit, Calico Hills nonwelded unit, and Crater Flat unit. Welded units have a mean fracture density of 8 to 40 fractures per unit cubic meter, mean matrix porosities of 12 to 23%, matrix hydraulic conductivities with geometric means ranging from 6.5 x 10 -6 to 9.8 x 10 -6 foot per day (2 x 10 -6 to 3 x 10 -6 meter per day), and bulk hydraulic conductivities of 0.33 to 33 feet per day (0.1 to 10 meters per day). The nonwelded units have a mean fracture density of 1 to 3 fractures per unit cubic meter, mean matrix porosities of 31 to 46%, and saturated hydraulic conductivities with geometric means ranging from 2.6 x 10 -5 to 2.9 x 10 -2 foot per day (8 x 10 -6 to 9 x 10 -3 meter per day). 15 refs., 4 figs., 1 tab

Completion Report for Well ER-EC-1

International Nuclear Information System (INIS)

Townsend, M.J.

2000-01-01

Well ER-EC-1 was drilled for the U.S. Department of Energy, Nevada Operations Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in the spring of 1999 as part of the U.S. Department of Energy's hydrogeologic investigation well program in the Western Pahute Mesa - Oasis Valley region just west of the Test Site. A 44.5-centimeter surface hole was drilled and cased off to the depth 675.1 meters below the surface. The hole diameter was then decreased to 31.1 centimeters for drilling to a total depth of 1,524.0 meters. A preliminary composite, static, water level was measured at the depth of approximately 566.3 meters prior to installation of the completion string. One completion string with three isolated, slotted intervals was installed in the well. Detailed lithologic descriptions with preliminary stratigraphic assignments are included in the report. These are based on composite drill cuttings collected every 3 meters and 31 sidewall samples taken at various depths below 680 meters, supplemented by geophysical log data. Detailed chemical and mineralogical studies of rock samples are in progress. The well penetrated Tertiary-age lava and tuff of the Timber Mountain Group, the Paintbrush Group, the Calico Hills Formation, the Crater Flat Group, and the Volcanics of Quartz Mountain. The preliminary geologic interpretation of data from Well ER-EC-1 indicates the presence of a structural trough or bench filled with a thick section of post-Rainier Mesa lava. These data also suggest that this site is located on a buried structural ridge that may separate the Silent Canyon and Timber Mountain caldera complexes

Freeze-Thaw Cycle Test on Basalt, Diorite and Tuff Specimens with the Simulated Ground Temperature of Antarctica

Science.gov (United States)

Park, J.; Hyun, C.; Cho, H.; Park, H.

2010-12-01

Physical weathering caused by freeze-thaw action in cold regions was simulated with artificial weathering simulator in laboratory. Physical weathering of rock in cold regions usually depends on the temperature, rock type and moisture content. Then these three variables were considered in this study. The laboratory freeze-thaw tests were conducted on the three types of rocks, e.g. diorite, basalt and tuff, which are the major rock types around Sejong Station, King George Island, Antarctica. Nine core samples composed of three samples from each rock type were prepared in NX core, and 50 cycles of freeze-thaw test was carried out under dried and saturated water conditions. In this study, the physical weathering of rocks was investigated after each 10 cycles by measuring P-wave velocity, bulk density, effective porosity, Schmidt hardness and uniaxial compression strength(UCS). The experimental result of the diorite and the tuff specimens showed that P-wave velocity, bulk density, effective porosity, Schmidt hardness and UCS were gradually decreased as weathering progresses, but the result of the basalt specimens did not show typical trends due to the characteristics of irregular pore distribution and various pore sizes. Scanning electron microscopy(SEM) photographs of diorite, basalt and tuff specimens weathered in dried and saturated conditions were also acquired to investigate the role of water during physical weathering processes. The number and size of microcracks were increased as weathering progresses. This work was supported by the National Research Foundation of Korea(NRF) Grant(NRF-2010-0027753).

The origin of Mauna Loa's Nīnole Hills: Evidence of rift zone reorganization

Science.gov (United States)

Zurek, Jeffrey; Williams-Jones, Glyn; Trusdell, Frank A.; Martin, Simon

2015-01-01

In order to identify the origin of Mauna Loa volcano's Nīnole Hills, Bouguer gravity was used to delineate density contrasts within the edifice. Our survey identified two residual anomalies beneath the Southwest Rift Zone (SWRZ) and the Nīnole Hills. The Nīnole Hills anomaly is elongated, striking northeast, and in inversions both anomalies merge at approximately −7 km above sea level. The positive anomaly, modeled as a rock volume of ~1200 km3 beneath the Nīnole Hills, is associated with old eruptive vents. Based on the geologic and geophysical data, we propose that the gravity anomaly under the Nīnole Hills records an early SWRZ orientation, now abandoned due to geologically rapid rift-zone reorganization. Catastrophic submarine landslides from Mauna Loa's western flank are the most likely cause for the concurrent abandonment of the Nīnole Hills section of the SWRZ. Rift zone reorganization induced by mass wasting is likely more common than currently recognized.

Report on static hydrothermal alteration studies of Topopah Spring tuff waters in J-13 water at 150{sup 0}C

Energy Technology Data Exchange (ETDEWEB)

Knauss, K.G.; Beiriger, W.B.

1984-08-31

This report presents the results of preliminary experimental work done to define the package environment in a potential nuclear waste repository in the Topopah Spring Member of the Paintbrush Tuff. The work is supported by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project as a part of the Waste Package task to design a package suitable for waste storage within volcanic units at the Nevada Test Site. Static hydrothermal alteration experiments were run for 4 months using polished wafers either fully submerged in an appropriate natural ground water or exposed to water-saturated air with enough excess water to allow refluxing. The aqueous results agreed favorably with similar experiments run using crushed tuff, and the use of solid polished wafers allowed us to directly evaluate the effects of reaction on the tuff. The results are preliminary in the sense that these experiments were run in Teflon-lined, static autoclaves, whereas subsequent experiments have been run in Dickson-type gold-cell rocking autoclaves. The results predict relatively minor changes in water chemistry, very minor alteration of the host rock, and the production of slight amounts of secondary minerals, when liquid water could return to the rock pores following the temperature maximum during the thermal period. 7 references, 16 figures, 10 tables.

Wine Industry Competitiveness: A survey of the Shawnee Hills American Viticultural Area

Directory of Open Access Journals (Sweden)

C. Matthew Rendleman

2016-06-01

Shawnee Hill׳s AVA winery owner/operators regard increases in regional tourism, growth in the US wine market continuous innovation, unique services and processes, and flow of information from customers to have the most enhancing effects on their businesses, and that confidence/trust in Illinois state political systems, tax systems, and administrative/bureaucratic regulations were the most constraining factors. Furthermore the Shawnee Hills AVA has growing competition, yet consists of innovative winery owners. It may currently lack external financial support, but with a community focus on product differentiation, the Shawnee Hills AVA has a chance, owners believe, to capture a portion of the growing market for regional products.

Theory of synergistic effects: Hill-type response surfaces as 'null-interaction' models for mixtures.

Science.gov (United States)

Schindler, Michael

2017-08-02

The classification of effects caused by mixtures of agents as synergistic, antagonistic or additive depends critically on the reference model of 'null interaction'. Two main approaches are currently in use, the Additive Dose (ADM) or concentration addition (CA) and the Multiplicative Survival (MSM) or independent action (IA) models. We compare several response surface models to a newly developed Hill response surface, obtained by solving a logistic partial differential equation (PDE). Assuming that a mixture of chemicals with individual Hill-type dose-response curves can be described by an n-dimensional logistic function, Hill's differential equation for pure agents is replaced by a PDE for mixtures whose solution provides Hill surfaces as 'null-interaction' models and relies neither on Bliss independence or Loewe additivity nor uses Chou's unified general theory. An n-dimensional logistic PDE decribing the Hill-type response of n-component mixtures is solved. Appropriate boundary conditions ensure the correct asymptotic behaviour. Mathematica 11 (Wolfram, Mathematica Version 11.0, 2016) is used for the mathematics and graphics presented in this article. The Hill response surface ansatz can be applied to mixtures of compounds with arbitrary Hill parameters. Restrictions which are required when deriving analytical expressions for response surfaces from other principles, are unnecessary. Many approaches based on Loewe additivity turn out be special cases of the Hill approach whose increased flexibility permits a better description of 'null-effect' responses. Missing sham-compliance of Bliss IA, known as Colby's model in agrochemistry, leads to incompatibility with the Hill surface ansatz. Examples of binary and ternary mixtures illustrate the differences between the approaches. For Hill-slopes close to one and doses below the half-maximum effect doses MSM (Colby, Bliss, Finney, Abbott) predicts synergistic effects where the Hill model indicates 'null

Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia

Science.gov (United States)

Foon, Junn Kitt; Clements, Gopalasamy Reuben; Liew, Thor-Seng

2017-01-01

Abstract Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition – a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak’s terrestrial malacofauna. PMID:28769723

Development of the data base for tuffs at Yucca Mountain, Nevada Test Site

International Nuclear Information System (INIS)

Lappin, A.R.

1981-11-01

The purposes of the data-base development described here are: (1) to provide sufficient input for the modeling and analysis required to support a horizon-selection decision in December, 1982; and (2) to support follow-on detailed horizon evaluation. Initial data collection must, therefore, be complete by August, 1982. Data will include; (1) thermal conductivity; (2) thermal expansion; (3) matrix and fracture mechanical properties; (4) bulk properties; and (5) functional thermomechanical stratigraphy of the tuffs at Yucca Mountain

Fertility in Hill Korwas -- a primitive tribe of Madhya Pradesh.

Science.gov (United States)

Pandey, G D; Tiwary, R S

1996-12-01

This study examines fertility behavior among 604 eligible couples in Hill Korwa tribes in Madhya Pradesh state, India. Low fertility patterns are compared to those of neighboring Gonds and nontribals from rural Jabalpur. The Hill Korwa are a subtribe of the Korwa, who remained in the hills and dense forests. Over 60% live in three tehsils of Surguja district, including Ambikapur tehsil where the study was conducted. Data were obtained in March 1991. Eligible couples were those where both partners live together and the noncontracepting wife is under age 50 and nonmenopausal. Only 3% were literate. Female marriage age was about 15 years. The median age was 23.8 years. 92% lived below the poverty line. The average number of children ever born (CEB) per couple was 1.9, compared to 2.5 for the Gond and 2.9 for nontribal couples. The CEB in a reproductive lifetime was 2.9, compared to 5.3 for Gond women and 5.9 for nontribal women. Fecundity among Hill Korwa women was 66% lower at younger ages (16-17 years and 17-18 years), and the differences increased with an increase in age at marriage. Hill Korwas had a low female age at marriage, low literacy, low percentages engaged in agriculture, and higher percentages living above the poverty line.

Midwest nukes tumble, rock industry: Byron, Marble Hill, Zimmer

International Nuclear Information System (INIS)

Nogee, A.

1984-01-01

The nuclear industry is suffering from a lack of investor confidence because of cancelled projects and the unprecedented rejection of an operating license for Commonwealth Edison's Byron plant on grounds that the utility failed to meet quality assurance responsibilities. When plans to complete the Zimmer and Marble Hill nuclear plants were abandoned, Bechtel came forward with a financing plan that, while rejected for Zimmer and Marble Hill, could lead to future bailouts. Both Zimmer and Marble Hill plants could be partially converted to coal. The loss of investor confidence in nuclear plants is largely due to political pressures brought on by a combination of citizen intervenors, whistle blowers on construction sites and disagreements between participating utilities. A rise in stock prices followed the cancellation announcements and the lowered investment security ratings

PRELIMINARY PALEOMAGNETIC RESULTS FROM OUTFLOW EOCENE-OLIGOCENE ASH FLOW TUFFS FROM THE WESTERN MARGIN OF THE SAN LUIS BASIN: IMPLICATION FOR THE KINEMATIC EVOLUTION OF THE RIO GRANDE RIFT

Science.gov (United States)

Mason, S. N.; Geissman, J. W.; Sussman, A. J.

2009-12-01

In the Rio Grande rift (RGR), a late Cenozoic continental rift from central Colorado to southern New Mexico, hanging wall margins typically contain en echelon normal fault systems with intervening areas of typically complex structure, called relay zones. Relay zones transfer displacement through complex strain patterns and eventual linkage of faults and hold clues as to how fault zones initiate and grow. The western margin of the RGR at the latitude of the San Luis basin (SLB) exposes laterally continuous Eocene-Oligocene volcanic rocks, well-correlated by 40Ar/39Ar data, and well-preserved rift structures. Ash flow tuffs are usually excellent recorders of the instantaneous geomagnetic field and five ash flow tuffs (ca. 32.3 to 27.3 Ma; including the Saguache Creek, La Jara Canyon, Masonic Park, Fish Canyon, and Carpenter Ridge tuffs) have been sampled in spatial detail along west to east transects of the eastern San Juan volcanic field to the westernmost margin of the RGR at the SLB. Data obtained from our sampling approach will yield a comprehensive definition of relative vertical-axis rotations across the area and will be used to assess the timing of RGR fault linkages. Preliminary paleomagnetic data from the Masonic Park tuff (ca. 28.2 Ma) suggest up to ~17° clockwise rotation between sample locations on the Colorado Plateau and locations to the east, nearest the western margin of the RGR. Preliminary data from the Fish Canyon tuff (ca. 27.8 Ma) show a ~12° clockwise rotation. The relative clockwise vertical-axis rotation of sampling sites in both ash flow tuffs nearest the RGR margin suggests that relay zone development with attending vertical-axis rotation played an important role in the opening of the northern RGR. Our data set is not sufficiently robust at present to test the hypothesis that rotation was taking place concurrently with eruption of these large-volume ash flow tuffs in the early Oligocene, but it is a possibility and if so, the RGR at the

New 40Ar/39Ar age of the Bishop Tuff from multiple sites and sediment rate calibration for the Matuyama-Brunhes boundary

Science.gov (United States)

Sarna-Wojcicki, A. M.; Pringle, M.S.; Wijbrans, J.

2000-01-01

Precise dating of sanidine from proximal ash flow Bishop Tuff and air fall Bishop pumice and ash, California, can be used to derive an absolute age of the Matuyama Reversed-Brunhes Normal (M-B) paleomagnetic transition, identified stratigraphically close beneath the Bishop Tuff and ash at many sites in the western United States. An average age of 758.9 ?? 1.8 ka, standard error of the mean (SEM), was obtained for individual sanidine crystals or groups of several crystals, determined from ???70 individual analyses of sanidine separates from 11 sample groups obtained at five localities. The basal air fall pumice (757.7 ?? 1.8 ka) and overlying ash flow tuff (762.2 ?? 4.7 ka) from near the source yield essentially the same dates within errors of analysis, suggesting that the two units were emplaced close in time. A date on distal Bishop air fall ash bed at Friant, California, ???100 km to the west of the source area, is younger, 750.1 ?? 4.3 ka, but not significantly different within analytical error (??1 standard deviation). Previous dates of the Bishop Tuff, obtained by others using conventional K-Ar and the fission track method on zircons, ranged from ???650 ka to ???1.0 Ma. The most recent, generally accepted date by the K-Ar method on sanidine was 738 ?? 3 ka. We infer, as others before, that many K-Ar dates on sanidine feldspar are too young owing to incomplete degassing of radiogenic Ar during fusion in the K-Ar technique and that many older K-Ar dates are too old owing to detrital or xenocrystic contamination in the larger samples that are necessary for the technique. The new dates are similar to recent 40Ar/39Ar ages of the Bishop Tuff determined on individual samples by others but are derived from a larger proximal sample population and from multiple analysis of each sample. The results provide a definitive and precise age calibration of this widespread chronostratigraphic marker in the western United States and northeastern Pacific Ocean. We calculated the

Preliminary calculations of release rates from spent fuel in a tuff repository

International Nuclear Information System (INIS)

Apted, M.J.; O'Connell, W.J.; Lee, K.H.; MacIntyre, A.T.; Ueng, T.S.; Pigford, T.H.; Lee, W.W.L.

1991-01-01

Time-dependent release rates of Tc-99, I-129, Cs-135, and Np-237 have been calculated for wet-drip and moist-continuous release modes from the engineered barrier system of a potential nuclear waste repository in unsaturated tuff, representative of a possible repository at Yucca Mountain in southern Nevada. We describe the modes of water contact and of release of dissolved radionuclides to the surrounding intact rock, and the corresponding calculational models. We list the parameter values adopted, and then present numerical results, conclusions, and recommendations. 21 refs., 5 figs., 2 tabs

Preliminary evaluation of alterant geophysical tomography in welded tuff

International Nuclear Information System (INIS)

Ramirez, A.L.; Daily, W.D.

1985-01-01

The ability of alterant geophysical tomography to delineate flow paths in a welded tuff rock mass has been preliminarily evaluated based on the results of a field experiment. Electromagnetic measurements were made before, during and after a water-based, dye tracer flowed through the rock mass. Alterant geophysical tomographs were generated and compared with independent evidence - borescope logs, neutron logs and dyed rock samples. Anomalies present in the tomograph match the location and orientation of fractures mapped with a borescope. The location of tracer-stained fractures coincides with the location of some image anomalies; other geophysical anomalies exist where tracer-stained fractures were not observed, perhaps due to poor core recovery. Additional drilling to locate stained flow paths and other experiments are planned so that the applicability of the technique can be further evaluated

Microhabitats of Merriam's turkeys in the Black Hills, South Dakota

Science.gov (United States)

Mark A. Rumble; Stanley H. Anderson

1996-01-01

Merriam’s Turkeys (Meleagris gallopavo merriami) are associated with ponderosa pine (Pinus ponderosa) forests in the western United States, but are not native to the ponderosa pine forest of the Black Hills, South Dakota. The Black Hills population was established by transplanting birds from New Mexico and Colorado between 1948 and...

Conceptualization of a hypothetical high-level nuclear waste repository site in unsaturated, fractured tuff

International Nuclear Information System (INIS)

Parsons, A.M.; Olague, N.E.; Gallegos, D.P.

1991-01-01

Under the sponsorship of the US Nuclear Regulatory Commission (NRC), Sandia National Laboratories (SNL) is developing a performance assessment methodology for the analysis of long-term disposal and isolation of high-level nuclear wastes (HLW) in alternative geologic media. As part of this exercise, SNL created a conceptualization of ground-water flow and radionuclide transport in the far field of a hypothetical HLW repository site located in unsaturated, fractured tuff formations. This study provides a foundation for the development of conceptual mathematical, and numerical models to be used in this performance assessment methodology. This conceptualization is site specific in terms of geometry, the regional ground-water flow system, stratigraphy, and structure in that these are based on information from Yucca Mountain located on the Nevada Test Site. However, in terms of processes in unsaturated, fractured, porous media, the model is generic. This report also provides a review and evaluation of previously proposed conceptual models of unsaturated and saturated flow and solute transport. This report provides a qualitative description of a hypothetical HLW repository site in fractured tuff. However, evaluation of the current knowledge of flow and transport at Yucca Mountain does not yield a single conceptual model. Instead, multiple conceptual models are possible given the existing information

Conceptualization of a hypothetical high-level nuclear waste repository site in unsaturated, fractured tuff

Energy Technology Data Exchange (ETDEWEB)

Parsons, A.M.; Olague, N.E.; Gallegos, D.P. [Sandia National Labs., Albuquerque, NM (USA)

1991-01-01

Under the sponsorship of the US Nuclear Regulatory Commission (NRC), Sandia National Laboratories (SNL) is developing a performance assessment methodology for the analysis of long-term disposal and isolation of high-level nuclear wastes (HLW) in alternative geologic media. As part of this exercise, SNL created a conceptualization of ground-water flow and radionuclide transport in the far field of a hypothetical HLW repository site located in unsaturated, fractured tuff formations. This study provides a foundation for the development of conceptual mathematical, and numerical models to be used in this performance assessment methodology. This conceptualization is site specific in terms of geometry, the regional ground-water flow system, stratigraphy, and structure in that these are based on information from Yucca Mountain located on the Nevada Test Site. However, in terms of processes in unsaturated, fractured, porous media, the model is generic. This report also provides a review and evaluation of previously proposed conceptual models of unsaturated and saturated flow and solute transport. This report provides a qualitative description of a hypothetical HLW repository site in fractured tuff. However, evaluation of the current knowledge of flow and transport at Yucca Mountain does not yield a single conceptual model. Instead, multiple conceptual models are possible given the existing information.

State of conservation of Santa Martha's hills, Colombia

International Nuclear Information System (INIS)

Lopez Salgado, Hector Jaime; Carbono Delahoz, Eduino

2006-01-01

The urban growth of Santa Marta and the occupation without planning of their surrounding hills, affect their natural conditions. The hills are part of the scenic beauty of the city and its conservation is indispensable to maintain the standard of life in her the vegetal cover corresponds to forests and scrubs of isomegathermic floor with xeromorphic characters, due to the low pluvial precipitation, this landscape characterizes the Colombian Caribbean coast in a narrow strip that extends from the south of the Guajira to the gulf of Morrosquillo. At the present time, only they are left surpluses in natural state, due to the floristic simplification of the vegetation, the introduction of invading species and modification of the landscape. The responsibility of the suitable handling of the urban space is imperative for the official, private sector and citizen institutions. The objective is to make an evaluation of the environmental conditions of hills of the city, in order to obtain basic elements, for the design of appropriate strategies of handling and its conservation. By means of the use of the GIS, with verification and aerial photo interpretation of field a multi-temporary study (1955-1993-2003) of the vegetal cover of the hills was elaborated that allowed to establish the happened changes. The execution of inventors allowed knowing the wealth and the structure floristic the vegetal cover of the area. The work was executed between May of the 2004 and May of the 2005

Mass, charge, and energy separation by selective acceleration with a traveling potential hill

Science.gov (United States)

Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

1996-10-01

A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to

Removal of ammonia from waste air streams with clinoptilolite tuff in its natural and treated forms

Czech Academy of Sciences Publication Activity Database

Ciahotný, K.; Melenová, L.; Jirglová, H.; Prokopová, Olga; Kočiřík, Milan; Eić, M.

2006-01-01

Roč. 12, č. 3 (2006), s. 219-226 ISSN 0929-5607 R&D Projects: GA ČR GA104/00/1007; GA ČR GP104/03/D183 Institutional research plan: CEZ:AV0Z40400503 Keywords : clinoptilolite tuffs * ammonia * adsorption * impregnation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.590, year: 2006

Thermal effects on water exclusion from a cavity in unsaturated tuff

International Nuclear Information System (INIS)

Zhou, W.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

1992-01-01

For an unsaturated, fractured porous medium subjected to uniform infiltration, we analyze thermal effects on water exclusion from cavities. This is of practical interest in a nuclear waste repository. A crucial question is: How much infiltration will lead to heated cavity-rock interface in tunnels and drifts being saturated so that water can enter a cavity. The combination of cavity size, dimensionless temperature difference, and infiltration rate that will lead to the critical condition at the cavity apex; this calculation considers the tuff matrix only. Here, the large projection area of the cavity intercepts large amounts of infiltration, requiring a lesser critical infiltration rate to saturate the cavity apex

Corrosion performance of metals and alloys in a tuff geochemical environment

International Nuclear Information System (INIS)

Van Konynenburg, R.A.; McCright, R.D.

1985-01-01

Reference and alternate alloy systems have been chosen for use in fabricating waste packages for a potential high-level nuclear waste repository in tuff. The main corrosion concerns have been identified. Testing performed to date indicates that austenitic stainless steels woul perform well as package materials under the expected conditions as well as the less likely extreme conditions so far postulated. Carbon steel appears to be adequate as a material for borehole liners. Copper-based alloys and Zircaloys are also undergoing corrosion testing, the former as alternate package materials, and the latter because of their presence as spent fuel cladding. 17 references, 2 tables

Archeological Investigations at Big Hill Lake, Southeastern Kansas, 1980.

Science.gov (United States)

1982-09-01

settled primarily along the Neosho river and Labette, Big Hill, and Pumpkin creeks. One of the first settlers in Osage township, in which Big Hill...slabs is not known at present. About 10 years later, in 1876, materials were reported- ly collected from an aboriginal site along Pumpkin creek...and length- ening its lifetime of use. As would therefore be expected, cracks are present between each of the paired holes on both of the two restored

Measurements of the near-surface flow over a hill

Science.gov (United States)

Vosper, S. B.; Mobbs, S. D.; Gardiner, B. A.

2002-10-01

The near-surface flow over a hill with moderate slope and height comparable with the boundary-layer depth is investigated through field measurements of the mean flow (at 2 m), surface pressure, and turbulent momentum flux divergence between 8 and 15 m. The measurements were made along an east-west transect across the hill Tighvein (height 458 m, approximate width 8 km) on the Isle of Arran, south-west Scotland, during two separate periods, each of around three-weeks duration. Radiosonde ascents are used to determine the variation of a Froude number, FL = U/NL, where U is the wind speed at the middle-layer height, hm, N is the mean Brunt-Väisälä frequency below this height and L is a hill length-scale. Measurements show that for moderately stratified flows (for which FL 0.25) a minimum in the hill-induced surface-pressure perturbation occurs across the summit and this is accompanied by a maximum in the near-surface wind speed. In the more strongly stratified case (FL 0.25) the pressure field is more asymmetric and the lee-slope flow is generally stronger than on the windward slope. Such a flow pattern is qualitatively consistent with that predicted by stratified linear boundary-layer and gravity-wave theories. The near-surface momentum budget is analysed by evaluating the dominant terms in a Bernoulli equation suitable for turbulent flow. Measurements during periods of westerly flow are used to evaluate the dominant terms, and the equation is shown to hold to a reasonable approximation on the upwind slope of the hill and also on the downwind slope, away from the summit. Immediately downwind of the summit, however, the Bernoulli equation does not hold. Possible reasons for this, such as non-separated sheltering and flow separation, are discussed.

Sorption and diffusion behavior of palladium in bentonite, granodiorite and tuff

International Nuclear Information System (INIS)

Tachi, Yukio; Shibutani, Tomoki; Sato, Haruo; Shibata, Masahiro

1999-06-01

Sorption and diffusion behavior palladium, which has been identified as one of the hazardous radionuclides in performance assessment of HLW disposal, in bentonite, granodiorite and tuff was studied in order to make reliable data set for the performance assessment. Sorption experiments of Pd on bentonite, granodiorite and tuff were conducted as functions of pH, ionic strength and liquid to solid ratio by batch method under aerobic conditions at room temperature. The distribution coefficients(K d ) of Pd on these solids were almost in the range of 10 -1 to 10 2 m 3 /kg and were in the order of bentonite > granodiorite ≅ tuff. The sorption trends with change in pH, ionic strength and liquid to solid ratio are very similar between three solids. The K d values were the highest pH 5 and decreased with increasing pH between 5 and 11. The effect of ionic strength on K d was not found in a range of 10 -2 to 10 -1 , but K d values increased with increasing liquid to solid ratio. The width of variation in K d was one order of magnitude in a liquid to solid ratio of 0.1 to 1 m 3 /kg. Sorption behavior of Pd is different from that of divalent metal ions such as Ni and Co etc. and chemical analogy may be inappropriate. The dominant aqueous species of Pd in the experimental conditions studied is estimated to be neutral species, Pd(OH) 2 (aq) by the thermodynamic calculations. The K d values of Pd on three solids were relatively high and uncharged complexes may be more strongly sorbed. The pH dependency of K d values suggests that Pd sorption is most likely to be occurring onto positively charged S-OH 2 2 type site which are progressively removed (to form SOH and SO - sites) at higher pH values. Diffusion behavior of Pd in bentonite was also studied by in-diffusion method as a function of dry density. The D a values obtained based on the instantaneous planar source model were in the orders of 10 -13 to 10 -12 m 2 /s and decreased with increasing dry density of bentonite. The K d

Novedades sobre el género Pilosella Hill.: (Asteraceae, Lactuceae) en España, II

OpenAIRE

Mateo Sanz, Gonzalo

2016-01-01

Se comunica la presencia de diversas especies nuevas del género Pilosella Hill. (Asteraceae, Lactuceae) en España. Novelties on the genus Pilosella Hill (Asteraceae, Lactuceae) in Spain, II. Several species of Pilosella Hill (Asteraceae, Lactuceae) found in Spain.

George William Hill, the Great but Unknown 19th Century Celestial Mechanician

Science.gov (United States)

Corbin, Brenda G.

2012-01-01

George William Hill (1838-1914) has long been considered one of the most famous and talented celestial mechanicians of the past century and a half. However, many people have never heard of him and his work. Simon Newcomb said he "will easily rank as the greatest master of mathematical astronomy during the last quarter of the nineteenth century.” After receiving a B.A. at Rutgers in 1859, Hill began work in 1861 at the office of the American Ephemeris and Nautical Almanac in Cambridge, MA. He moved to Washington with the group in 1882 which then became part of the U. S. Naval Observatory. Newcomb, beginning his work on planetary motion, assigned the theory of Jupiter and Saturn to him, calling it about the most difficult topic. Hill's work was published by the USNO in 1890 as A New Theory of Jupiter and Saturn. From 1898 to 1901, Hill lectured on the subject of celestial mechanics at Columbia University in a position created just for him. After 1892 and until his death, he lived at the family homestead in West Nyack, NY. He never married, was something of a recluse, and spent most of his time with his books and research. Hill was an amateur botanist and enjoyed exploring on long walks in the countryside. Many honors and awards came to him during his lifetime, both from the U.S. and abroad, including serving as president of the American Mathematical Society. All of Hill's mathematical and astronomical research was incorporated in The Collected Mathematical Works of George William Hill. This work, containing a preface in French by Poincare, was published in 4 large volumes by the Carnegie Institution of Washington in 1905.

Investigation of bacterial transport in the large-block test, a thermally perturbed block of Topopah Spring Tuff

International Nuclear Information System (INIS)

Chen, C. I.; Chuu, Y. J.; Lin, W.; Meike, A.; Sawvel, A.

1998-01-01

This study investigates the transport of bacteria in a large, thermally perturbed block of Topopah Spring tuff. The study was part of the Large-Block Test (LBT), thermochemical and physical studies conducted on a 10 ft x 10 ft x 14 ft block of volcanic tuff excavated on 5 of 6 sides out of Fran Ridge, Nevada. Two bacterial species, Bacillus subtilis and Arthrobacter oxydans, were isolated from the Yucca Mountain tuff. Natural mutants that can grow under the simultaneous presence of the two antibiotics, streptomycin and rifampicin, were selected from these species by laboratory procedures. The double-drug-resistant mutants, which could be thus distinguished from the indigenous species, were injected into the five heater boreholes of the large block hours before heating was initiated. The temperature, as measured 5 cm above one of the heater boreholes, rose slowly and steadily over a matter of months to a maximum of 142 C. Samples (cotton cloths inserted the length of the hole, glass fiber swabs, and filter papers) were collected from the boreholes that were approximately 5 ft below the injection points. Double-drug-resistant bacteria were found in the collection boreholes nine months after injection. Surprisingly, they also appeared in the heater boreholes where the temperature had been sustainably high throughout the test. These bacteria appear to be the species that were injected. The number of double-drug-resistant bacteria that were identified in the collection boreholes increased with time. An apparent homogeneous distribution among the observation boreholes and heater boreholes suggests that a random motion could be the pattern that the bacteria migrated in the block. These observations indicated the possibility of rapid bacterial transport in a thermally perturbed geologic setting

Multi-scale habitat use of male ruffed grouse in the Black Hills National Forest

Science.gov (United States)

Cassandra L. Mehls; Kent C. Jensen; Mark A. Rumble; Michael C. Wimberly

2014-01-01

Ruffed grouse (Bonasa umbellus) are native upland game birds and a management indicator species (MIS) for aspen (Populus tremuloides) in the Black Hills National Forest (Black Hills). Our objective was to assess resource selection of male ruffed grouse to identify the most appropriate scale to manage for aspen and ruffed grouse in the Black Hills. During spring 2007...

Excavation effects on tuff - recent findings and plans for investigations at Yucca Mountain

International Nuclear Information System (INIS)

Blejwas, T.E.; Zimmerman, R.M.; Shephard, L.E.

1989-01-01

Plans for site-characterization testing and constructing an exploratory shaft facility (ESF) at Yucca Mountain, Nevada, have been influenced by the construction and monitoring of stable openings in G-Tunnel on the Nevada Test Site. G-Tunnel provides access for testing in a thin bed of unsaturated welded tuff that is similar to that at Yucca Mountain. The data from the experiments in the ESF will be used to validate analytical methods for predicting the response of underground openings to the excavation process and to the heat generated by the waste

The international INTRAVAL project. Phase 2, working group 1 report. Flow and tracer experiments in unsaturated tuff and soil. Las Cruces trench and Apache Leap tuff studies

International Nuclear Information System (INIS)

Nicholson, T.J.; Guzman-Guzman, A.; Hills, R.; Rasmussen, T.C.

1997-01-01

The Working Group 1 final report summaries two test case studies, the Las Cruces Trench (LCT), and Apache Leap Tuff Site (ALTS) experiments. The objectives of these two field studies were to evaluate models for water flow and contaminant transport in unsaturated, heterogeneous soils and fractured tuff. The LCT experiments were specifically designed to test various deterministic and stochastic models of water flow and solute transport in heterogeneous, unsaturated soils. Experimental data from the first tow LCT experiments, and detailed field characterisation studies provided information for developing and calibrating the models. Experimental results from the third experiment were held confidential from the modellers, and were used for model comparison. Comparative analyses included: point comparisons of water content; predicted mean behavior for water flow; point comparisons of solute concentrations; and predicted mean behavior for tritium transport. These analyses indicated that no model, whether uniform or heterogeneous, proved superior. Since the INTRAVAL study, however, a new method has been developed for conditioning the hydraulic properties used for flow and transport modelling based on the initial field-measured water content distributions and a set of scale-mean hydraulic parameters. Very good matches between the observed and simulated flow and transport behavior were obtained using the conditioning procedure, without model calibration. The ALTS experiments were designed to evaluate characterisation methods and their associated conceptual models for coupled matrix-fracture continua over a range of scales (i.e., 2.5 centimeter rock samples; 10 centimeter cores; 1 meter block; and 30 meter boreholes). Within these spatial scales, laboratory and field tests were conducted for estimating pneumatic, thermal, hydraulic, and transport property values for different conceptual models. The analyses included testing of current conceptual, mathematical and physical

Numerical Simulation Analysis of Seismic of Frame Structure on Hill Terrain

Directory of Open Access Journals (Sweden)

Weng Weisu

2017-01-01

Full Text Available In recent year, Wenchuan,Ya’an,Yushu and other areas in china occur a series of high earthquake, however areas of earthquake is similar as mountainous terrain, building structure of seismic increasingly aroused our concern, and the research that hill topography affected building structure seismic in shallow mountain. The research content mainly includes: through modelling was built by the ANSYS software, the cooperative effects of a ten layer of frame structure- hill system were calculation. First, simple comparative dynamic characteristics analysis of soil - structure interaction and the rigid foundation assumption conditions; Second, put Hill-Soil-Structure Interaction(referred to as HSSI and Soil - Structure - Interaction(referred to as SSI further analysis of the dynamic response, including: including structural modal analysis (vibration mode, cycle, the time history analysis (such as displacement, internal force and acceleration and so on. Through Hill-Soil-Structure Interaction research, taking each factor in consideration, giving structure seismic key technology measures about shallow mountain to provide reference for such structure theory research.

DOE to accept bids for Elk Hills crude

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that the Department of Energy will accept bids in a reoffering sale covering 53,400 b/d of Elk Hills field oil but later may exercise an option to cut sales volumes and ship 20,000 b/d to Strategic Petroleum Reserve sites in Texas. DOE rejected all 19 bids submitted in an earlier semiannual sale of crude oil from the California naval petroleum reserve, saying they were too low. DOE the, The unique combination of federal and state government policies affecting the movement of oil into and out of the California market has contributed to a situation in which it apparently is very difficult for the government to receive a price for Elk Hills oil that satisfies the minimum price tests that govern the sale of Elk Hills oil. The 12 winning bids in the reoffering sale averaged $13.58/bbl, with bids for the higher quality Stevens zone crude averaging $13.92/bbl, about 67 cents/bbl higher than bids rejected last month. DOE the 20,000 b/d is all local pipelines can ship to the interstate All-American pipeline for transfer to Texas beginning in June

Petrography, mineralogy, and chemistry of calcite-silica deposits at Exile Hill, Nevada, compared with local spring deposits

International Nuclear Information System (INIS)

Vaniman, D.T.; Chipera, S.J.; Bish, D.L.

1995-12-01

Chemical, mineralogic, and petrographic analyses of siliceous calcretes from Exile Hill east of Yucca Mountain, Nevada, indicate that pedogenic processes alone account for the formation of the calcretes. These calcretes have been interpreted by some observers as evidence of seismically triggered eruptions of deep water. Such an origin could have important consequences if Yucca Mountain is developed as an unsaturated site for the disposal of high-level nuclear waste. At odds with this hypothesis are the absence of features that should be present at fault-fed springs (e.g., fissure-ridge mounds with microterraces) and the preservation within root casts of delicate pedogenic microfossils, such as calcified filaments and needle-fiber calcites. Mineral-chemical evidence of pedogenic origin is found in heavy-mineral concentrations, reflected in Fe and Sc enrichments. These concentrations, which occur in the most massive of the vein calcretes, require derivation of detritus from a mixture of weathered and eolian materials that occur in the overlying B soil horizons, as opposed to direct incorporation of adjacent unweathered bedrock. Carbonate and silica abundances and accumulation rates are well within the scope of pedogenic processes. Calcium is derived from rainwater or eolian sources, whereas silica is derived in part by dissolution of local volcanic glasses or from dissolution of unstable silica minerals that are abundant in the local tuffs. In contrast with local deposits that are of spring or seep origin, the siliceous calcretes at Yucca Mountain are pedogenic in origin as well as evolution and provide no evidence in support of conjectured spring activity

Rare Plants and Animals of the Texas Hill Country: Educator's Guide.

Science.gov (United States)

Texas State Dept. of Parks and Wildlife, Austin.

Texas Hill Country is a land of fresh water springs, stony hills, and steep canyons and home to many rare plants and animals. Six activities for grades 3-5 and six activities for grades 6-12 are contained in this guide. Elementary activity highlights include using "The Lorax" by Dr. Seuss to stimulate critical thinking about…

Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

Science.gov (United States)

Okubo, Chris H.

2012-01-01

Volcanic ash is thought to comprise a large fraction of the Martian equatorial layered deposits and much new insight into the process of faulting and related fluid flow in these deposits can be gained through the study of analogous terrestrial tuffs. This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in fine-grained, poorly indurated volcanic ash by investigating exposures of faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah. The porosity and granularity of the host rock are found to control the style of localized strain that occurs prior to and contemporaneous with faulting. Deformation bands occur in tuff that was porous and granular at the time of deformation, while fractures formed where the tuff lost its porous and granular nature due to silicic alteration. Non-localized deformation of the host rock is also prominent and occurs through compaction of void space, including crushing of pumice clasts. Significant off-fault damage of the host rock, resembling fault pulverization, is recognized adjacent to one analog fault and may reflect the strain rate dependence of the resulting fault zone architecture. These findings provide important new guidelines for future structural analyses and numerical modeling of faulting and subsurface fluid flow through volcanic ash deposits on Mars.

Gravitational slope-deformation of a resurgent caldera: New insights from the mechanical behaviour of Mt. Nuovo tuffs (Ischia Island, Italy)

Science.gov (United States)

Marmoni, G. M.; Martino, S.; Heap, M. J.; Reuschlé, T.

2017-10-01

Ischia Island (Italy) is an impressive example of the rare phenomenon of caldera resurgence. The emplacement and replenishment of magmas at shallow depth resulted in a vertical uplift of about 900 m, concentrated in the western portion of Mt. Epomeo (789 m a.s.l.). As a consequence of this uplift, the island has experienced several slope instabilities at different scales since the Holocene, from shallow mass movements to large rock and debris avalanches. These mass wasting events, which mobilised large volumes of greenish alkali-trachytic tuff (the Mt. Epomeo Green Tuff, MEGT), were strictly related to volcano-tectonic activity and the interaction between the volcanic slopes and the hydrothermal system beneath the island. Deep-Seated Gravitational Slope Deformation (DSGSD) at Mt. Nuovo, located adjacent to densely populated coastal villages, is an ongoing process that covers an area of 1.6 km2. The Mt. Nuovo DSGSD involves a rock mass volume of 190 Mm3 and is accommodated by a main shear zone and a series of sub-vertical fault zones associated with high-angle joint sets. To improve our understanding of this gravity-induced process, we performed a physical (porosity and permeability) and mechanical (uniaxial and triaxial deformation experiments) characterisation of two ignimbrite deposits - both from the MEGT - that form a significant component of the NW sector of Mt. Epomeo. The main conclusions drawn from our experiments are twofold. First, the presence of water dramatically reduces the strength of the tuffs, suggesting that the movement of fluids within the hydrothermal system could greatly impact slope stability. Second, the transition from brittle (dilatant) to ductile (compactant) behaviour in the tuffs of the MEGT occurs at a very low effective pressure, analogous to a depth of a couple of hundred metres, and that this transition is likely moved closer to the surface in the presence of water. We hypothesise that compactant (porosity decreasing) behaviour at

Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

Directory of Open Access Journals (Sweden)

Rosalba Alonso-Rodriguez

2012-05-01

Full Text Available The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2; after hydrolysis, the carbamate toxins (epimers GTX2/3 were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.

Conditioning exercises in ski jumping: biomechanical relationship of squat jumps, imitation jumps, and hill jumps.

Science.gov (United States)

Lorenzetti, Silvio; Ammann, Fabian; Windmüller, Sabrina; Häberle, Ramona; Müller, Sören; Gross, Micah; Plüss, Michael; Plüss, Stefan; Schödler, Berni; Hübner, Klaus

2017-11-22

As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force-time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training.

Experimental research on sealing of boreholes, shafts and ramps in welded tuff

International Nuclear Information System (INIS)

Fuenkajorn, K.

1996-01-01

Laboratory and in-situ experiments have been conducted to determine the mechanical and hydraulic performance of cement borehole seals in densely welded Apache Leap tuff. Test results indicate that under saturated conditions, commercial expansive cement can provide good bond strength and adequate hydraulic performance for borehole seal under changing stress conditions. The cement seal should be installed at the intact portion of the opening, and should have a length-to-diameter ratio greater than four. Drying increases borehole plug permeability and decreases mechanical and hydraulic bonds at the plug-rock interface. In-situ testing indicates that installation procedure may significantly affect the cement plug performance

Criticality characteristics of mixtures of plutonium, silicon dioxide, Nevada tuff, and water

International Nuclear Information System (INIS)

Sanchez, R.; Myers, W.; Hayes, D.

1997-01-01

The nuclear criticality characteristics of mixtures of plutonium, silicon dioxide, and water (Part A) or plutonium, silicon dioxide, Nevada Yucca Mountain tuff, and water (Part B) have become of interest because of the appearance of recent papers on the subject. These papers postulate that if excess weapons plutonium is vitrified into a silicate log and buried underground, a self-sustaining neutron chain reaction may develop given sufficient time and interaction with the burial medium. Moreover, given specific geologic actions resulting in postulated configurations, the referenced papers state that nuclear explosions could occur with multi-kiloton yields or yields equivalent to hundreds of tons of TNT

Comparison of Speed-Up Over Hills Derived from Wind-Tunnel Experiments, Wind-Loading Standards, and Numerical Modelling

Science.gov (United States)

Safaei Pirooz, Amir A.; Flay, Richard G. J.

2018-03-01

We evaluate the accuracy of the speed-up provided in several wind-loading standards by comparison with wind-tunnel measurements and numerical predictions, which are carried out at a nominal scale of 1:500 and full-scale, respectively. Airflow over two- and three-dimensional bell-shaped hills is numerically modelled using the Reynolds-averaged Navier-Stokes method with a pressure-driven atmospheric boundary layer and three different turbulence models. Investigated in detail are the effects of grid size on the speed-up and flow separation, as well as the resulting uncertainties in the numerical simulations. Good agreement is obtained between the numerical prediction of speed-up, as well as the wake region size and location, with that according to large-eddy simulations and the wind-tunnel results. The numerical results demonstrate the ability to predict the airflow over a hill with good accuracy with considerably less computational time than for large-eddy simulation. Numerical simulations for a three-dimensional hill show that the speed-up and the wake region decrease significantly when compared with the flow over two-dimensional hills due to the secondary flow around three-dimensional hills. Different hill slopes and shapes are simulated numerically to investigate the effect of hill profile on the speed-up. In comparison with more peaked hill crests, flat-topped hills have a lower speed-up at the crest up to heights of about half the hill height, for which none of the standards gives entirely satisfactory values of speed-up. Overall, the latest versions of the National Building Code of Canada and the Australian and New Zealand Standard give the best predictions of wind speed over isolated hills.

Distance-Based Functional Diversity Measures and Their Decomposition: A Framework Based on Hill Numbers

Science.gov (United States)

Chiu, Chun-Huo; Chao, Anne

2014-01-01

Hill numbers (or the “effective number of species”) are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify “the effective number of equally abundant and (functionally) equally distinct species” in an assemblage. We also propose a class of mean functional diversity (per species), which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total) functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity) quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma) can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation) measures, including N-assemblage functional generalizations of

Distance-based functional diversity measures and their decomposition: a framework based on Hill numbers.

Directory of Open Access Journals (Sweden)

Chun-Huo Chiu

Full Text Available Hill numbers (or the "effective number of species" are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify "the effective number of equally abundant and (functionally equally distinct species" in an assemblage. We also propose a class of mean functional diversity (per species, which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation measures, including N-assemblage functional

The Hill's three-body problem: a new deduction of motion equations

International Nuclear Information System (INIS)

Fuente Marcos, C. de la.

1995-01-01

Although the Hill's problem has been considered traditionally as a particular case of the restricted problem, it is not but rather a different problem with the same degree of generality. In this paper it is presented a new derivation of the motion equations obtained originally by Hill in 1878 as well as a brief discussion about its possible applications. (Author) 13 refs

Experimental Analyses of Yellow Tuff Spandrels of Post-medieval Buildings in the Naples Area

International Nuclear Information System (INIS)

Calderoni, B.; Cordasco, E. A.; Lenza, P.; Guerriero, L.

2008-01-01

Experimental analyses have been carried out on tuff masonry specimens in order to investigate the structural behaviour of historical buildings in the Naples area (Southern Italy). Spandrels of post-medieval buildings (late XVI to early XX century) have been analysed, with emphasis on morphological characteristics according to chronological indicators. Results of the experimentation on scaled models (1:10) are discussed and the better behaviour of historical masonry typologies on respect to the modern one is highlighted. Comparison with theoretical formulations of ultimate shear resistance are provided too

Sorption and diffusion behavior of palladium in bentonite, granodiorite and tuff

Energy Technology Data Exchange (ETDEWEB)

Tachi, Yukio; Shibutani, Tomoki; Sato, Haruo [Radiochemistry Group, Waste Isolation Research Division, Waste Management and Fuel Cycle Research Center, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Shibata, Masahiro [Barrier Performance Group, Waste Isolation Research Division, Waste Management and Fuel Cycle Research Center, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

1999-06-01

Sorption and diffusion behavior palladium, which has been identified as one of the hazardous radionuclides in performance assessment of HLW disposal, in bentonite, granodiorite and tuff was studied in order to make reliable data set for the performance assessment. Sorption experiments of Pd on bentonite, granodiorite and tuff were conducted as functions of pH, ionic strength and liquid to solid ratio by batch method under aerobic conditions at room temperature. The distribution coefficients(K{sub d}) of Pd on these solids were almost in the range of 10{sup -1} to 10{sup 2} m{sup 3}/kg and were in the order of bentonite > granodiorite {approx_equal} tuff. The sorption trends with change in pH, ionic strength and liquid to solid ratio are very similar between three solids. The K{sub d} values were the highest pH 5 and decreased with increasing pH between 5 and 11. The effect of ionic strength on K{sub d} was not found in a range of 10{sup -2} to 10{sup -1}, but K{sub d} values increased with increasing liquid to solid ratio. The width of variation in K{sub d} was one order of magnitude in a liquid to solid ratio of 0.1 to 1 m{sup 3}/kg. Sorption behavior of Pd is different from that of divalent metal ions such as Ni and Co etc. and chemical analogy may be inappropriate. The dominant aqueous species of Pd in the experimental conditions studied is estimated to be neutral species, Pd(OH){sub 2}(aq) by the thermodynamic calculations. The K{sub d} values of Pd on three solids were relatively high and uncharged complexes may be more strongly sorbed. The pH dependency of K{sub d} values suggests that Pd sorption is most likely to be occurring onto positively charged S-OH{sub 2}{sup 2} type site which are progressively removed (to form SOH and SO{sup -} sites) at higher pH values. Diffusion behavior of Pd in bentonite was also studied by in-diffusion method as a function of dry density. The D{sub a} values obtained based on the instantaneous planar source model were in the

Consideration of Nuclear Criticality When Directly Disposing Highly Enriched Spent Nuclear Fuel in Unsaturated Tuff - II: Geochemical Constraints

International Nuclear Information System (INIS)

Rechard, Rob P.; Sanchez, Lawrence C.; Trellue, Holly R.

2003-01-01

This article presents several reasonable cases in which four mechanisms - dissolution, physical mixing, adsorption, and precipitation (either chemical change or evaporation) - might concentrate fissile material in and around a disposal container for radioactive waste at the proposed repository at Yucca Mountain, Nevada. The possible masses, concentrations, and volume are then compared to criticality limits. The cases examined evaluate the geologic barrier role in preventing criticality since engineered options for preventing criticality (e.g., boron or gadolinium neutron absorber in the disposal container) are not considered. The solid concentrations able to form in the natural environment are insufficient for criticality to occur because (a) solutions of 235 U and 239 Pu are clearly not critical; (b) physical mixing of fissile material with the entire potential iron oxide (as goethite - FeOOH) in a waste package is not critical; (c) the adsorption of 239 Pu on consolidated iron oxide in a waste package is not critical; (d) the adsorption of 235 U on consolidated iron oxide in a waste package is not critical when accounting for reduced adsorption because of carbonates at high pH; (e) the filtration of iron oxide colloids, containing fissile material, by the thin invert material is not critical; (f) insufficient retention through precipitation of 235 U or 239 Pu occurs in the invert; (g) adsorption of 235 U and 239 Pu on devitrified or clinoptolite-rich tuff below the repository is not critical; (h) the average precipitation/adsorption of 235 U as uranyl silicates in the tuff is not critical by analogy with calcite deposition in lithophysae at Yucca Mountain; and (i) precipitation/adsorption (caused by cyclic drying) as uranyl silicates on fracture surfaces of the tuff is not critical by analogy with the oxidation of UO 2 , migration of U VI , and precipitation in fractures at the Nopal I ore deposit in Mexico

Manganese-oxide minerals in fractures of the Crater Flat Tuff in drill core USW G-4, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Carlos, B.A.; Bish, D.L.; Chipera, S.J.

1990-07-01

The Crater Flat Tuff is almost entirely below the water table in drill hole USW G-4 at Yucca Mountain, Nevada. Manganese-oxide minerals from the Crater Flat Tuff in USW G-4 were studied using optical, scanning electron microscopic, electron microprobe, and x-ray powder diffraction methods to determine their distribution, mineralogy, and chemistry. Manganese-oxide minerals coat fractures in all three members of the Crater Flat Tuff (Prow Pass, Bullfrog, and Tram), but they are most abundant in fractures in the densely welded devitrified intervals of these members. The coatings are mostly of the cryptomelane/hollandite mineral group, but the chemistry of these coatings varies considerably. Some of the chemical variations, particularly the presence of calcium, sodium, and strontium, can be explained by admixture with todorokite, seen in some x-ray powder diffraction patterns. Other chemical variations, particularly between Ba and Pb, demonstrate that considerable substitution of Pb for Ba occurs in hollandite. Manganese-oxide coatings are common in the 10-m interval that produced 75% of the water pumped from USW G-4 in a flow survey in 1983. Their presence in water-producing zones suggests that manganese oxides may exert a significant chemical effect on groundwater beneath Yucca Mountain. In particular, the ability of the manganese oxides found at Yucca Mountain to be easily reduced suggests that they may affect the redox conditions of the groundwater and may oxidize dissolved or suspended species. Although the Mn oxides at Yucca Mountain have low exchange capacities, these minerals may retard the migration of some radionuclides, particularly the actinides, through scavenging and coprecipitation. 23 refs., 21 figs., 2 tabs

Analysis of automobile’s automatic control systems for the hill climbing start

Directory of Open Access Journals (Sweden)

Valeriy I. Klimenko

2014-12-01

Full Text Available To improve road safety while driving on the rise, facilitating the driver’s activity the automobile industry leaders are introducing automatic hill-hold control systems into the car design. This study purpose relates to the existing automatic start control systems’ design analysis. Analyzed are the existing design developments of automatic hill start assist control systems applied for driving at the start of the climbing. The effected research allows to select the scheme for further development of start driving automatic control systems. Further improvement of driving control systems and primarily the driver assistance hill-hold control systems is necessary to increase both the driving comfort and the traffic safety.

Review of the thermal stability and cation exchange properties of the zeolite minerals clinoptilolite, mordenite, and analcime; applications to radioactive waste isolation in silicic tuff

International Nuclear Information System (INIS)

Smyth, J.R.; Caporuscio, F.A.

1981-06-01

Silicic tuffs of the southern Great Basin and basalts of the Columbia River Plateau are under investigation as potential host rocks for high- and intermediate-level radioactive wastes. Nonwelded and partially welded tuffs may contain major amounts (> 50%) of the zeolite minerals clinoptilolite, mordenite, and analcime. Densely welded tuffs and some basalt flows may contain clinoptilolite as fracture filling that limits the permeability of these rocks. The cation exchange properties of these zeolite minerals allow them to pose a formidable natural barrier to the migration of cationic species of various radionuclides in aqueous solutions. However, these minerals are unstable at elevated temperatures and at low water-vapor pressures and may break down either by reversible dehydration or by irreversible mineralogical reactions. All the breakdown reactions occurring at increased temperature involve a net volume reduction and evolution of fluids. Thus, they may provide a pathway (shrinkage fractures) and a driving force (fluid pressure) for release of radionuclides to the biosphere. These reactions may be avoided by keeping zeolite-bearing horizons saturated with water and below about 85 0 C. This may restrict allowable gross thermal loadings in waste repositories in volcanic rocks

The Kapsiki of the Mandara Hills

NARCIS (Netherlands)

Beek, van W.E.A.

1987-01-01

The Kapsiki of Cameroon and the Higi of Nigeria are two tribes from the Mandara hills area of central and western Africa. Though they form one coherent group of villages, they are usually considered as two separate ethnic units. The author normally uses the term Kapsiki for both. Based on fieldwork

77 FR 2128 - Southwest Pennsylvania Railroad Company-Acquisition Exemption-Laurel Hill Development Corporation

Science.gov (United States)

2012-01-13

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35584] Southwest Pennsylvania Railroad Company--Acquisition Exemption-- Laurel Hill Development Corporation Southwest... 49 CFR 1150.41 to acquire a number of rail lines now owned by Laurel Hill Development Corporation...

The volcanic foundation of Dutch architecture : Use of Rhenish tuff and trass in the Netherlands in the past two millennia

NARCIS (Netherlands)

Nijland, TG; van Hees, R.P.J.

2016-01-01

Occasionally, a profound but distant connection between volcano and culture exists. This is the case between the volcanic Eifel region in Germany and historic construction in the Netherlands, with the river Rhine as physical and enabling connection. Volcanic tuff from the Eifel comprises a

Investigation of periodic systems by means of the generalized Hill method

International Nuclear Information System (INIS)

Baitin, A.V.; Ivanov, A.A.

1994-01-01

We propose the new method of investigation of infinite periodic determination which is a generalized Hill method. This method has been used for finding of the characteristic value for the Hill equation. finding the band structure of the one-dimensional periodic and obtaining of the dispersion equation for the electromagnetic wave propagation in the waveguide by plasma arbitrary periodic density modulation by plasma arbitrary periodic density modulation

77 FR 33560 - Southwest Pennsylvania Railroad Company-Acquisition Exemption-Laurel Hill Development Corporation

Science.gov (United States)

2012-06-06

... Pennsylvania Railroad Company--Acquisition Exemption-- Laurel Hill Development Corporation Southwest... 49 CFR 1150.41 to acquire a 0.66-mile line of railroad owned by Laurel Hill Development Corporation... rail line. Most recently, in Southwest Pennsylvania Railroad Company--Acquisition Exemption--Laurel...

Evidence to the Marley Hill Public Inquiry

Energy Technology Data Exchange (ETDEWEB)

Wilson, G.K. (Council for the Protection of Rural England (UK). Durham and Teesdale Branch)

1989-11-01

George Kenneth Wilson, a retired power station enginer, and holder of such offices as Vice-Chairman of the CPRE Durham and Teesdale Branch, Secretary of the Derwent Valley Protection Society and an officer of the Opencast Mining Intelligence Group, presents reasons for dismissing the appeal for opencast mining at the Marley Hill site in the NE of England saying that the Mineral Planning Guidance Note, MPG3 seemed to be repeating mistakes inherent in the previous 'Plan for coal'. He considers that the application cannot be justified on the grounds of demand or forecast market trends. The type of coal is unsuitable for local power station boilers. The working of the site would destroy a large area of pleasant countryside. The standard of restoration of the 32 sites surrounding Marley Hill is in his opinion very poor.

Reaction of Bullfrog tuff with J-13 well water at 900C and 1500C

International Nuclear Information System (INIS)

Oversby, V.M.; Knauss, K.G.

1983-01-01

A series of experiments was conducted on crushed tuff at 90 0 C and 150 0 C and on core wafer samples at 150 0 C. The results show the following: increasing the ratio of rock to water increases the rate of approach to steady-state concentrations in solution. Surface outcrop samples of Bullfrog tuff contain a minor component of highly soluble material believed to be a residue from the evaporation of surface runoff water in the pores of the rock. This material can be removed by shaking the crushed rock with water at room temperature and subjecting it briefly to heat with fresh water. Solution analyses for unfiltered samples that have reacted for short periods show higher concentrations of Al and Fe than do analyses for filtered samples; results for other elements are independent of filtration. This difference probably exists because of particulate matter in the solutions that dissolves when the samples are acidified prior to analysis. Agitation of samples during reaction produces sub-0.1 μ particles in the solutions. These particles dissolve when samples are acidified, resulting in abnormally high concentration values for some elements, such as Al and Fe. Comparison of the results for crushed rock with those for core wafers shows that the method of sample preparation does not have a large effect on the results of rock-water interaction studies

Geochemical homogeneity of tuffs at the potential repository level, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Peterman, Zell E.; Cloke, Paul

2001-01-01

In a potential high-level radioactive waste repository at Yucca Mountain, Nevada, radioactive waste and canisters, drip shields protecting the waste from seepage and from rock falls, the backfill and invert material of crushed rock, the host rock, and water and gases contained within pores and fractures in the host rock together would form a complex system commonly referred to as the near-field geochemical environment. Materials introduced into the rock mass with the waste that are designed to prolong containment collectively are referred to as the Engineered Barrier System, and the host rock and its contained water and gases compose the natural system. The interaction of these component parts under highly perturbed conditions including temperatures well above natural ambient temperatures will need to be understood to assess the performance of the potential repository for long-term containment of nuclear waste. The geochemistry and mineralogy of the rock mass hosting the emplacement drifts must be known in order to assess the role of the natural system in the near-field environment. Emplacement drifts in a potential repository at Yucca Mountain would be constructed in the phenocryst-poor member of the Topopah Spring Tuff which is composed of both lithophysal and nonlithophysal zones. The chemical composition of the phenocryst-poor member has been characterized by numerous chemical analyses of outcrop samples and of core samples obtained by surface-based drilling. Those analyses have shown that the phenocryst-poor member of the Topopah Spring Tuff is remarkably uniform in composition both vertically and laterally. To verify this geochemical uniformity and to provide rock analyses of samples obtained directly from the potential repository block, major and trace elements were analyzed in core samples obtained from drill holes in the cross drift, which was driven to provide direct access to the rock mass where emplacement drifts would be constructed

Hill functions for stochastic gene regulatory networks from master equations with split nodes and time-scale separation

Science.gov (United States)

Lipan, Ovidiu; Ferwerda, Cameron

2018-02-01

The deterministic Hill function depends only on the average values of molecule numbers. To account for the fluctuations in the molecule numbers, the argument of the Hill function needs to contain the means, the standard deviations, and the correlations. Here we present a method that allows for stochastic Hill functions to be constructed from the dynamical evolution of stochastic biocircuits with specific topologies. These stochastic Hill functions are presented in a closed analytical form so that they can be easily incorporated in models for large genetic regulatory networks. Using a repressive biocircuit as an example, we show by Monte Carlo simulations that the traditional deterministic Hill function inaccurately predicts time of repression by an order of two magnitudes. However, the stochastic Hill function was able to capture the fluctuations and thus accurately predicted the time of repression.

Penerapan Metode Hill Climbing Pada Sistem Informasi Geografis Untuk Mencari Lintasan Terpendek

Directory of Open Access Journals (Sweden)

Eka Vickraien Dangkua

2016-04-01

Full Text Available Heuristic search methods is one of the methods commonly in use in finding the shortest path, one of which, namely the methods Hill Climbing process where testing is done using heuristic functions. Problems generally encountered is the shortest path search to solve the problem of distance can be changed into a graph structure, where the point of declaring the city and the State line that connects the two cities. From the logic so that it can locate destinations and save on travel costs. The hallmarks of this algorithm are all possible solutions will have then checked one by one from the left side, so it will be obtained solutions with optimal results. On a Hill Climbing method according to case using geographic information systems as a tool in making a decision, by way of collect, examine, and analyze information related to digital map. with a combination of Hill Climbing method and geographic information systems can result in an application that is certainly feasible for use in the search path problems.   Keywords: Hill Climbin method; digital map; Geographic Information Systems

Water quality impacts from mining in the Black Hills, South Dakota, USA

International Nuclear Information System (INIS)

Rahn, P.H.; Davis, A.D.; Webb, C.J.; Nichols, A.D.

1996-01-01

The focus of this research was to determine if abandoned mines constitute a major environmental hazard in the Black Hills. Many abandoned gold mines in the Black Hills contribute acid and heavy metals to streams. In some areas of sulfide mineralization local impacts are severe, but in most areas the impacts are small because most ore deposits consist of small quartz veins with few sulfides. Pegmatite mines appear to have negligible effects on water due to the insoluble nature of pegmatite minerals. Uranium mines in the southern Black Hills contribute some radioactivity to surface water, but he impact is limited because of the dry climate and lack of runoff in that area. 26 refs

Transport properties of Topopah Spring tuff

International Nuclear Information System (INIS)

Lin, W.; Daily, W.

1984-10-01

Electrical resistivity, ultrasonic P-waves velocity, and water permeability were measured simultaneously on both intact and fractured Topopah Spring tuff samples at a confining pressure of 5.0 MPa, pore pressures to 2.5 MPa, and temperatures to 140 0 C. The tested samples were subjected to three dehydration and rehydration cycles. The dehydrations were accomplished at a temperature of 140 0 C, and the rehydrations were accomplished at various combinations of temperature and pore pressures so that the wetting fluid was either liquid water, steam or both. The electrical resistivity measurements indicate that for the intact sample, the drying and resaturation took place fairly uniformly throughout the sample. On the other hand, for the fractured sample, the drying and resaturation was spatially quite nonuniform. When samples had been subjected to 5 MPa of confining pressure and 140 0 C for several weeks, a gradual monotonic drift in resistivity was measured (decreasing resistivity when dry; increasing resistivity when wet). This may be the result of either minerological changes or grain boundary movement. In any case, the phenomenon may have important consequences on long term repository performance, and should be studied further. The permeability of the intact sample was independent of temperature, dehydration and rehydration cycles, and time. The permeability of the fractured sample, initially dominated by the fracture, decreased by about one order of magnitude after each dehydration and rehydration cycle. 11 references, 12 figures, 3 tables

Sharing the Gift of Jazz: An Interview with Willie L. Hill Jr.

Science.gov (United States)

Howe, Brad

2011-01-01

This article presents an interview with Willie L. Hill Jr., founder and director of the Society for Jazz Education. Currently a professor of music education at the University of Massachusetts-Amherst and the director of the UMass Fine Arts Center, Hill has served as director of education for the Thelonious Monk Institute of Jazz. He is a past…

Completion Report for Well ER-20-12: Corrective Action Units 101 and 102: Central and Western Pahute Mesa

Energy Technology Data Exchange (ETDEWEB)

Wurtz, Jeff [Navarro-Intera, LLC (N-I), Las Vegas, NV (United States)

2016-08-01

Well ER-20-12 was drilled for the U.S. Department of Energy, Nevada National Security Administration Nevada Field Office in support of the Underground Test Area Activity. The well was drilled from October 2015 to January 2016 as an addition to the Central and Western Pahute Mesa corrective action units 101 and 102 the Phase II drilling program. Well ER-20-12 was identified based on recommendations of the Pahute Mesa Guidance Team as a result of anomalous tritium detections in groundwater samples collected from Well PM-3 in 2011 and 2013. The primary purpose of the well was to provide information on the hydrogeology in the area downgradient of select underground tests on Western Pahute Mesa and define hydraulic properties in the saturated Tertiary volcanic rocks. The main 46.99-centimeter (cm) (18.5-inch [in.]) borehole was drilled to a depth of 765.14 meters (m) (2,510.3 ft) and the hole opened to 66.04 cm (26 in.); followed by the 50.80-cm (20-in.) surface casing, which was installed and sealed with cement; and a piezometer (p4) was set in the Timber Mountain welded-tuff aquifer (TMWTA) between the casing and the open borehole. The borehole was continued with a 46.99-cm (18.5-in.) drill bit to a depth of 1,326.53 m (4,352.16 ft), and an intermediate 24.44-cm (9.625-in.) casing was installed and sealed to 1,188.72 m (3,900.00 ft) A piezometer (p3) was installed across the Calico Hills zeolitic composite unit (CHZCM) (lava-flow aquifer [LFA]) in the annulus of the open borehole. Two additional piezometers were installed and completed between the intermediate casing and the borehole wall, one (p2) in the CHZCM and one (p1) in the Belted Range aquifer (BRA). The piezometers are set to monitor groundwater properties in the completed intervals. The borehole was continued with a 21.59-cm (8.5-in.) drill bit to a total depth of 1,384.80 m (4,543.33 ft), and the main completion 13.97-cm (5.5-in.) casing was installed in the open borehole across the Pre-Belted Range

Completion Report for Well ER-20-12: Corrective Action Units 101 and 102: Central and Western Pahute Mesa

International Nuclear Information System (INIS)

Wurtz, Jeff

2016-01-01

Well ER-20-12 was drilled for the U.S. Department of Energy, Nevada National Security Administration Nevada Field Office in support of the Underground Test Area Activity. The well was drilled from October 2015 to January 2016 as an addition to the Central and Western Pahute Mesa corrective action units 101 and 102 the Phase II drilling program. Well ER-20-12 was identified based on recommendations of the Pahute Mesa Guidance Team as a result of anomalous tritium detections in groundwater samples collected from Well PM-3 in 2011 and 2013. The primary purpose of the well was to provide information on the hydrogeology in the area downgradient of select underground tests on Western Pahute Mesa and define hydraulic properties in the saturated Tertiary volcanic rocks. The main 46.99-centimeter (cm) (18.5-inch) borehole was drilled to a depth of 765.14 meters (m) (2,510.3 ft) and the hole opened to 66.04 cm (26 in.); followed by the 50.80-cm (20-in.) surface casing, which was installed and sealed with cement; and a piezometer (p4) was set in the Timber Mountain welded-tuff aquifer (TMWTA) between the casing and the open borehole. The borehole was continued with a 46.99-cm (18.5-in.) drill bit to a depth of 1,326.53 m (4,352.16 ft), and an intermediate 24.44-cm (9.625-in.) casing was installed and sealed to 1,188.72 m (3,900.00 ft) A piezometer (p3) was installed across the Calico Hills zeolitic composite unit (CHZCM) (lava-flow aquifer [LFA]) in the annulus of the open borehole. Two additional piezometers were installed and completed between the intermediate casing and the borehole wall, one (p2) in the CHZCM and one (p1) in the Belted Range aquifer (BRA). The piezometers are set to monitor groundwater properties in the completed intervals. The borehole was continued with a 21.59-cm (8.5-in.) drill bit to a total depth of 1,384.80 m (4,543.33 ft), and the main completion 13.97-cm (5.5-in.) casing was installed in the open borehole across the Pre-Belted Range composite

Mammals of Kalimpong Hills, Darjeeling District, West Bengal, India

Directory of Open Access Journals (Sweden)

J.K. Mallick

2012-10-01

Full Text Available Neora Valley National Park (NVNP in the Kalimpong Hills, Darjeeling District, having a wide range of altitudinal variations (183-3,200 m and climatic conditions and forming an ecological trijunction with Sikkim and Bhutan, is the last virgin wilderness in West Bengal. It is a global hotspot for the unique ecosystem, where tropical, sub-tropical, temperate and sub-temperate forests represent a wealth of biodiversity including many threatened and rare mammals. It is the prime habitat of Ailurus fulgens (estimated population 28-32, Neofelis nebulosa (population unassessed, Ursus thibetanus (18, Bos gaurus (81, Hemitragus jemlahicus (32, Naemorhedus goral (73, Capricornis sumatraensis (89, Rusa unicolor (286, Muntiacus vaginalis (590 and Sus scrofa (615. Discovery of Panthera tigris (20 in 1998 prompted the forest department to include NVNP as a sensitive wildlife zone. Many authors recorded the mammalian diversity in Darjeeling District since the mid-nineteenth century, but most of them referred to the Darjeeling Hills. The documentations on Kalimpong Hills are scarce because of the dense canopy, thick undergrowth and inaccessible terrain, particularly in the pristine forests of Neora Valley. Consequently, a comprehensive compendium of the mammals in this region was not prepared. A study was undertaken in 2008-2009 with a view to bridging this knowledge-gap and presenting an updated account of the mammalian species in this new short-listed World Heritage Site and surrounding forests of the Kalimpong Hills based on literature review, questionnaire survey, direct sighting and indirect evidences. During June-October 1916, N.A. Baptista recorded 29 mammalian species (22 genera out of 563 specimens collected, from the region. The present study registered 99 species (68 genera after 94 years.

Micro-topography showing the landslide-origin of the Marumori hill, Matsukawa geothermal field Iwate Prefecture, Japan

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Tomomasa; Ikeda, Kazuo; Sumi, Seiai

1988-07-27

The Marumori Hill in the Matsukawa geothermal field has been previously considered to be a central cone or a lava dome in a caldera. Airphotogeological study, topographical surveying, and trenching are carried out in order to clarify the origin of the hill. Fifty six topographic linearments trending NE-SW direction distributed parallelly were detected on the top area and the northern flank of the hill. This linearment swarm is composed of the alternated small ranges and valleys with asymmetric profiles similar to cuesta topography. These topographic features are considered to be formed under the tensional stress field trending NW-SE direction on the surface of a landslide block. The hill is inferred to be not a lava dome but a landslide block which slide down from the steep scarp north and west of the hill. The age of the landslide is dated back to be older than 2400 years B.P. according to 14C age of the humic strata covering the hill. (7 figs, 1 tab, 14 refs)

The sorption of uranium and technetium on bentonite, tuff and granodiorite

International Nuclear Information System (INIS)

Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Cowper, M.M.; Heath, T.G.; Tweed, C.J.

1995-01-01

A combined experimental and modeling study of the sorption of uranium and technetium on geological materials has been carried out as part of the PNC program to increase confidence in the performance assessment for a high-level radioactive waste (HLW) repository in Japan. Batch sorption experiments have been performed in order to study the sorption of uranium and technetium onto bentonite, tuff and granodiorite from both equilibrated seawater and de-ionized water under strongly-reducing and non-reducing conditions. A preliminary study of the sorption of uranium on mineral surfaces in granodiorite has also been undertaken using a nuclear microprobe. Mathematical modeling using the geochemical speciation program HARPHRQ in conjunction with the HATCHES database has been carried out in order to interpret the results of the sorption experiments

"Beverly Hills 90210" : kes mida teeb / Tiina Lepiste

Index Scriptorium Estoniae

Lepiste, Tiina

2003-01-01

Aaron Spellingu produtseeritud ja 2000. aastal lõpetatud menuseriaalis "Beverly Hills 90210" osalenud näitlejate edaspidisest elust seoses plaaniga teha täispikk mängufilm "10 Year High School Reunion"

Distribution of moisture, tritium, and plutonium in the alluvium, aquifer, and underlying tuff in Mortandad Canyon

International Nuclear Information System (INIS)

Purtymun, W.D.; Maes, M.N.; Peters, R.

1985-01-01

A study of the distribution of moisture, tritium, and plutonium in the Mortandad Canyon aquifer indicates some infiltration of water into the underlying tuff. This infiltration was accompanied by similar movement of tritium. The concentrations of plutonium on the sediments in the aquifer were low when compared with the high concentrations in solution in an ionic complex that does not readily exchange or is adsorbed by clay minerals in the alluvium. 2 references, 4 figures, 2 tables

The timing and origin of pre- and post-caldera volcanism associated with the Mesa Falls Tuff, Yellowstone Plateau volcanic field

Science.gov (United States)

Stelten, Mark E.; Champion, Duane E.; Kuntz, Mel A.

2018-01-01

We present new sanidine 40Ar/39Ar ages and paleomagnetic data for pre- and post-caldera rhyolites from the second volcanic cycle of the Yellowstone Plateau volcanic field, which culminated in the caldera-forming eruption of the Mesa Falls Tuff at ca. 1.3 Ma. These data allow for a detailed reconstruction of the eruptive history of the second volcanic cycle and provide new insights into the petrogenesis of rhyolite domes and flows erupted during this time period. 40Ar/39Ar age data for the biotite-bearing Bishop Mountain flow demonstrate that it erupted approximately 150 kyr prior to the Mesa Falls Tuff. Integrating 40Ar/39Ar ages and paleomagnetic data for the post-caldera Island Park rhyolite domes suggests that these five crystal-rich rhyolites erupted over a centuries-long time interval at 1.2905 ± 0.0020 Ma (2σ). The biotite-bearing Moonshine Mountain rhyolite dome was originally thought to be the downfaulted vent dome for the pre-caldera Bishop Mountain flow due to their similar petrographic and oxygen isotope characteristics, but new 40Ar/39Ar dating suggest that it erupted near contemporaneously with the Island Park rhyolite domes at 1.2931 ± 0.0018 Ma (2σ) and is a post-caldera eruption. Despite their similar eruption ages, the Island Park rhyolite domes and the Moonshine Mountain dome are chemically and petrographically distinct and are not derived from the same source. Integrating these new data with field relations and existing geochemical data, we present a petrogenetic model for the formation of the post-Mesa Falls Tuff rhyolites. Renewed influx of basaltic and/or silicic recharge magma into the crust at 1.2905 ± 0.0020 Ma led to [1] the formation of the Island Park rhyolite domes from the source region that earlier produced the Mesa Falls Tuff and [2] the formation of Moonshine Mountain dome from the source region that earlier produced the biotite-bearing Bishop Mountain flow. These magmas were stored in the crust for less than a few thousand

Fitful and protracted magma assembly leading to a giant eruption, Youngest Toba Tuff, Indonesia

Science.gov (United States)

Reid, Mary R; Vazquez, Jorge A.

2017-01-01

The paroxysmal eruption of the 74 ka Youngest Toba Tuff (YTT) of northern Sumatra produced an extraordinary 2800 km3 of non-welded to densely welded ignimbrite and co-ignimbrite ash-fall. We report insights into the duration of YTT magma assembly obtained from ion microprobe U-Th and U-Pb dates, including continuous age spectra over >50% of final zircon growth, for pumices and a welded tuff spanning the compositional range of the YTT. A relatively large subpopulation of zircon crystals nucleated before the penultimate caldera-related eruption at 501 ka, but most zircons yielded interior dates 100-300 ka thereafter. Zircon nucleation and growth was likely episodic and from diverse conditions over protracted time intervals of >100 to >500 ka. Final zircon growth is evident as thin rim plateaus that are in Th/U chemical equilibrium with hosts, and that give crystallization ages within tens of ka of eruption. The longevity and chemical characteristics of the YTT zircons, as well as evidence for intermittent zircon isolation and remobilization associated with magma recharge, is especially favored at the cool and wet eutectoid conditions that characterize at least half of the YTT, wherein heat fluxes could dissolve major phases but have only a minor effect on larger zircon crystals. Repeated magma recharge may have contributed to the development of compositional zoning in the YTT but, considered together with limited allanite, quartz, and other mineral dating and geospeedometry, regular perturbations to the magma reservoir over >400 ka did not lead to eruption until 74 ka ago.

Review of Barrow Hill: Curse of the Ancient Circle PC Game

OpenAIRE

Michael Charno

2007-01-01

Archaeological video games are few and far between. Internet Archaeology has reviewed a number of archaeologically-based computer applications, but none that in my opinion would fall under the video game category. Barrow Hill: Curse of the ancient circle from Shadow Tor Studios, is a video game…with archaeology in it. It would be a stretch to claim that Barrow Hill is actually an archaeological video game, but it does have an occasionally solid archaeological foundation and back story.

Crystallization Stages of the Bishop Tuff Magma Body Recorded in Crystal Textures in Pumice Clasts

Energy Technology Data Exchange (ETDEWEB)

Pamukcu, Ayla; Gualda, Guilherme A.R.; Anderson, Jr. , Alfred T. (Vanderbilt); (UC)

2012-07-25

The Bishop Tuff is a giant silicic ignimbrite erupted at 0.76 Ma in eastern California, USA. Five pumice clasts from the late-erupted Bishop Tuff (Aeolian Buttes) were studied in an effort to better understand the pre- and syn-eruptive history of the Bishop magma body and place constraints on the timescales of its existence. This study complements and expands on a previous study that focused on early-erupted Bishop Tuff pumice clasts. Bulk densities of pumice clasts were measured using an immersion method, and phenocryst crystal contents were determined using a sieving and winnowing procedure. X-ray tomography was used to obtain qualitative and quantitative textural information, particularly crystal size distributions (CSDs). We have determined CSDs for crystals ranging in size from {approx}10 to {approx}1000 {micro}m for three groups of mineral phases: magnetite ({+-}ilmenite), pyroxene + biotite, quartz + feldspar. Similar to early-erupted pumice, late-erupted pumice bulk density and crystal contents are positively correlated, and comparison of crystal fraction vs size trends suggests that the proportion of large crystals is the primary control on crystallinity. Porosity is negatively correlated with crystal content, which is difficult to reconcile with closed-system crystallization. Magnetite and pyroxene + biotite size distributions are fractal in nature, often attributed to fragmentation; however, crystals are mostly whole and euhedral, such that an alternative mechanism is necessary to explain these distributions. Quartz + feldspar size distributions are kinked, with a shallow-sloped log-linear section describing large crystals (> 140 {micro}m) and a steep-sloped log-linear section describing small crystals (< 140 {micro}m). We interpret these two crystal populations as resulting from a shift in crystallization regime. We suggest that the shallow-sloped section describes a pre-eruptive quartz + feldspar growth-dominated regime, whereas the steep

Sedimentology and uranium potential of the Inyan Kara Group, near Buffalo Gap, South Dakota. Final report

International Nuclear Information System (INIS)

Dandavati, K.S.; Fox, J.E.

1980-04-01

Sedimentary structures, along with textural and compositional evidence gathered from two stratigraphic sections of the Lower Cretaceous Inyan Kara Group in Calico and Fuson Canyons on the southeastern flank of the Black Hills, suggest the following depositional framework: the basal, Chilson Member of the Lakota Formation consists of a series of upward fining sequences deposited in point-bar and flood-plain environments of a northeasterly flowing, meandering river system. Fluvial sandstones in the Chilson include channel-fill, channel margin, crevasse microdelta and levee facies. The Minnewaste Limestone Member and the lower part of the overlying Fuson Member of the Lakota Formation were deposited in low-energy, lacustrine environments. Flood oriented tidal-delta facies overlain by tidal flat deposits in the upper part of the Fuson Member suggest an earlier incursion of the initial Cretaceous seaway, at least locally, than previously documented in the region. Lower Fall River deposits represent northeast-trending barrier bar and northwest-trending deltaic distributary mouth bar facies, reflecting an increase in sediment supply. Upper Fall River sandstones include distributary mouth bar and lower foreshore deposits. Altered sandstones of the basal Chilson Member and the lower part of the Fuson Member in Calico Canyon contain anomalous values of U 3 O 8 . Fossil wood and bone samples are also enriched in trace elements of U, V, and Mo, suggesting that uranium-bearing solutions might have passed through porous and permeable sandstones of the study area, possibly flowing toward the northeast along Chilson paleochannels

Structure and evolution of the Horse Heaven Hills in South-Central Washington

International Nuclear Information System (INIS)

Hagood, M.C.

1986-03-01

The purpose of this study is to describe the structure and evolution of the Horse Heaven Hills uplift at its abrupt structural transition. This was achieved by: (1) delineating the structure within the two trends as they approach the intersection; (2) determining the timing and location of uplift within each trend; (3) comparing and contrasting Miocene vertical growth rates along folds within both trends; and (4) imposing constraints for tectonic models that pertain to the genesis of the Horse Heaven Hills uplift. These objectives can only be fulfilled if the stratigraphy of the area is first delineated. Data from this study suggest that tectonic models that directly or indirectly pertain to the origin of the Horse Heaven Hills uplift may be constrained by: (1) the predominance of monoclinal or near-monoclinal fold geometries and reverse faults along both the northwest and northeast trends; (2) preliminary data which suggest clockwise rotation has occurred along folds of both trends; (3) folds along both trends developing simultaneously and at similar rates (at least during Wanapum and Saddle Mountains time); (4) folds along the northwest trend of the Horse Heaven Hills uplift being genetically related to and forming simultaneously with at least certain folds along the Rattlesnake-Wallula structural alignment; (5) the uplift developing simultaneously with the north-northwest-trending Hog Ranch-Naneum Ridge anticline as well as other Yakima folds during at least Columbia River Basalt Group time. It is proposed that folds of both trends of the Horse Heaven Hills uplift were generated by the same tectonic processes

Spatial variability of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, southwestern Utah

Science.gov (United States)

Okubo, C. H.

2012-12-01

In order to yield new insight into the process of faulting in fine-grained, poorly indurated volcanic ash, the distribution of strain around faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah, is investigated. Several distinct styles of inelastic strain are identified. Deformation bands are observed in tuff that is porous and granular in nature, or is inferred to have been so at the time of deformation. Where silicic alteration is pervasive, fractures are the dominant form of localized strain. Non-localized strain within the host rock is manifest as pore space compaction, including crushing of pumice clasts. Distinct differences in fault zone architecture are observed at different magnitudes of normal fault displacement, in the mode II orientation. A fault with cm-scale displacements is manifest as a single well-defined surface. Off-fault damage occurs as pore space compaction near the fault tips and formation of deformation band damage zones that are roughly symmetric about the fault. At a fault with larger meter-scale displacements, a fault core is present. A recognizable fault-related deformation band damage zone is not observed here, even though large areas of the host rock remain porous and granular and deformation bands had formed prior to faulting. The host rock is instead fractured in areas of pervasive alteration and shows possible textural evidence of fault pulverization. The zones of localized and distributed strain have notably different spatial extents around the causative fault. The region of distributed deformation, as indicated by changes in gas permeability of the macroscopically intact rock, extends up to four times farther from the fault than the highest densities of localized deformation (i.e., fractures and deformation bands). This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in poorly indurated tuff. Not surprisingly, the type of

Public Computer Usage in Chapel Hill Public Library

Data.gov (United States)

Town of Chapel Hill, North Carolina — Data collected November 2014 - May 2016. As of June 2016, this data is no longer collected on a continual basis.This dataset includes frequency and length of use of...

40Ar/(39)Ar geochronology and paleomagnetic stratigraphy of the Lukeino and lower Chemeron Formations at Tabarin and Kapcheberek, Tugen Hills, Kenya.

Science.gov (United States)

Deino, Alan L; Tauxe, Lisa; Monaghan, Marc; Hill, Andrew

2002-01-01

(40)Ar/(39)Ar single-crystal laser-fusion dating, K-Ar dating, and paleomagnetic reversal stratigraphy have been used to determine the chronostratigraphy of the Kabarnet Trachyte, Lukeino Formation, Kaparaina Basalt Formation, and Chemeron Formation at the sites of Kapcheberek (BPRP#77) and Tabarin (BPRP#77) in the Tugen Hills, Kenya. The succession ranges in age from 6.56-3.8 Ma. The upper Lukeino Formation at Kapcherberek, including the fauna from the site BPRP#76, was deposited during chron C3r and can be constrained to the interval 5.88-5.72 Ma. The Chemeron Formation at Tabarin includes at the base an ignimbrite and associated basal air-fall tuff with a combined age of 5.31+/-0.03 Ma. Sedimentary and volcaniclastic rocks of the Chemeron Formation which unconformably overlie the ignimbrite record chrons C3n.2n through C2Ar. The combined(40)Ar/(39)Ar and paleomagnetic data constrain the age of this sequence to 4.63-3.837 Ma. The age of the Tabarin mandible fragment (KNM-TH 13150) and associated fauna at site BPRP#77 in the Chemeron Formation is 4.48-4.41 Ma, marginally older than similar early hominids from Aramis, Ethiopia. Basin subsidence appears to be defining an overall accumulation rate of about 17 cm/ka over the 2.7 Ma represented at Tabarin and Kapcheberek, despite episodes of rapid accumulation and hiatuses. Copyright 2002 Academic Press.

Leaching Process of Rare Earth Elements, Gallium and Niobium in a Coal-Bearing Strata-Hosted Rare Metal Deposit—A Case Study from the Late Permian Tuff in the Zhongliangshan Mine, Chongqing

OpenAIRE

Jianhua Zou; Heming Tian; Zhen Wang

2017-01-01

The tuff, a part of coal-bearing strata, in the Zhongliangshan coal mine, Chongqing, southwestern China, hosts a rare metal deposit enriched in rare earth elements (REE), Ga and Nb. However, the extraction techniques directly related to the recovery of rare metals in coal-bearing strata have been little-studied in the literature. The purpose of this paper is to investigate the extractability of REE, Ga and Nb in the tuff in the Zhongliangshan mine using the alkaline sintering-water immersion-...

Profiles in medical courage: causation and Austin Bradford Hill

Directory of Open Access Journals (Sweden)

Robbins RA

2012-09-01

Full Text Available Austin Bradford Hill was a British epidemiologist and statistician who is best remembered for two landmark pulmonary studies. He was the statistician on the Medical Research Council Streptomycin in Tuberculosis Trial. This is regarded as the first randomized clinical trial. The second was the demonstration of the connection between cigarette smoking and lung cancer. However, Hill’s most lasting contribution may be his establishment of a group of conditions necessary to provide adequate evidence of a causal relationship between an incidence and a consequence, widely known as the Bradford Hill Criteria of Causation. In this profile of medical courage we examine his remarkable background that led to the epidemiological equivalent of Koch’s postulates.

Review of Barrow Hill: Curse of the Ancient Circle PC Game

Directory of Open Access Journals (Sweden)

Michael Charno

2007-01-01

Full Text Available Archaeological video games are few and far between. Internet Archaeology has reviewed a number of archaeologically-based computer applications, but none that in my opinion would fall under the video game category. Barrow Hill: Curse of the ancient circle from Shadow Tor Studios, is a video game…with archaeology in it. It would be a stretch to claim that Barrow Hill is actually an archaeological video game, but it does have an occasionally solid archaeological foundation and back story.

2013 strategic petroleum reserve big hill well integrity grading report.

Energy Technology Data Exchange (ETDEWEB)

Lord, David L.; Roberts, Barry L.; Lord, Anna C. Snider; Bettin, Giorgia; Sobolik, Steven Ronald; Park, Byoung Yoon; Rudeen, David Keith; Eldredge, Lisa; Wynn, Karen; Checkai, Dean; Perry, James Thomas

2014-02-01

This report summarizes the work performed in developing a framework for the prioritization of cavern access wells for remediation and monitoring at the Big Hill Strategic Petroleum Reserve site. This framework was then applied to all 28 wells at the Big Hill site with each well receiving a grade for remediation and monitoring. Numerous factors affecting well integrity were incorporated into the grading framework including casing survey results, cavern pressure history, results from geomechanical simulations, and site geologic factors. The framework was developed in a way as to be applicable to all four of the Strategic Petroleum Reserve sites.

Solar heating and hot water system installed at Cherry Hill, New Jersey

Science.gov (United States)

1979-01-01

The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat

Science.gov (United States)

Coussens, Maya; Cassidy, Michael; Watt, Sebastian F. L.; Jutzeler, Martin; Talling, Peter J.; Barfod, Dan; Gernon, Thomas M.; Taylor, Rex; Hatter, Stuart J.; Palmer, Martin R.; Montserrat Volcano Observatory

2017-03-01

Volcanism on Montserrat (Lesser Antilles arc) has migrated southwards since the formation of the Silver Hills 2.5 Ma, and has formed three successively active volcanic centres. The Centre Hills volcano was the focus of volcanism from 1-0.4 Ma, before activity commenced at the currently active Soufrière Hills volcano. The history of activity at these two volcanoes provides an opportunity to investigate the pattern of volcano behaviour on an andesitic arc island over the lifetime of individual volcanoes. Here, we describe the pyroclastic stratigraphy of subaerial exposures around central Montserrat; identifying 11 thick (> 1 m) pumiceous units derived from sustained explosive eruptions of Centre Hills from 0.8-0.4 Ma. Over 10 other, less well- exposed pumiceous units have also been identified. The pumice-rich units are interbedded with andesite lava breccias derived from effusive, dome-forming eruptions of Centre Hills. The stratigraphy indicates that large (up to magnitude 5) explosive eruptions occurred throughout the history of Centre Hills, alongside effusive activity. This behaviour at Centre Hills contrasts with Soufrière Hills, where deposits from sustained explosive eruptions are much less common and restricted to early stages of activity at the volcano, from 175-130 ka. Subsequent eruptions at Soufriere Hills have been dominated by andesitic effusive eruptions. The bulk composition, petrography and mineral chemistry of volcanic rocks from Centre Hills and Soufrière Hills are similar throughout the history of both volcanoes, except for occasional, transient departures to different magma compositions, which mark shifts in vent location or dominant eruption style. For example, the final recorded eruption of Centre Hills, before the initiation of activity at Soufrière Hills, was more silicic than any other identified eruption on Montserrat; and the basaltic South Soufrière Hills episode marked the transition to the current stage of predominantly effusive

Ce-Fe-modified zeolite-rich tuff to remove Ba(2+)-like (226)Ra(2+) in presence of As(V) and F(-) from aqueous media as pollutants of drinking water.

Science.gov (United States)

Olguín, María Teresa; Deng, Shuguang

2016-01-25

The sorption behavior of the Ba(2+)-like (226)Ra(2+) in the presence of H2AsO4(-)/HAsO4(2-) and F(-) from aqueous media using Ce-Fe-modified zeolite-rich tuff was investigated in this work. The Na-modified zeolite-rich tuff was also considered for comparison purposes. The zeolite-rich tuff collected from Wyoming (US) was in contact with NaCl and CeCl3-FeCl3 solutions to obtain the Na- and Ce-Fe-modified zeolite-rich tuffs (ZUSNa and ZUSCeFe). These zeolites were characterized by scanning electron microscopy and X-ray diffraction. The BET-specific surface and the points of zero charge were determined as well as the content of Na, Ce and Fe by neutron activation analysis. The textural characteristics and the point of zero charge were changed by the presence of Ce and Fe species in the zeolitic network. A linear model described the Ba(2+)-like (226)Ra(2+) sorption isotherms and the distribution coefficients (Kd) varied with respect to the metallic species present in the zeolitic material. The As(V) oxianionic chemical species and F(-) affected this parameter when the Ba(2+)-like (226)Ra(2+)-As(V)-F(-) solutions were in contact with ZUSCeFe. The H2AsO4(-)/HAsO4(2-) and F(-) were adsorbed by ZUSCeFe in the same amount, independent of the concentration of Ba(2+)-like (226)Ra(2+) in the initial solution. Copyright © 2015 Elsevier B.V. All rights reserved.

Gender, professionalization, and the child in the Progressive Era: Patty Smith Hill, 1868-1946.

Science.gov (United States)

Allen, Ann Taylor

2011-01-01

This article discusses the career of Patty Smith Hill, a major figure in the American kindergarten movement, in the context of the Progressive Era in American history. Hill, an educator and child-welfare activist, became known both as a reformer of early-childhood education and as an advocate of the inclusion of the kindergarten, originally a private institution, in public-school systems. The article acknowledges this as one of the most significant achievements of the woman-led reform movements of the Progressive Era, but at the same time notes that it involved a substantial transfer of power from the women who had originally developed the kindergarten to the male principals and superintendants who now supervised kindergarten teachers, often without much understanding of their distinctive methods and aims. As a professor at Columbia Teachers College, Hill also exercised an international influence. Hill's career exemplifies broader patterns of women's professionalization during the late-nineteenth and early-twentieth centuries.

Outcomes of arthroscopic "Remplissage": capsulotenodesis of the engaging large Hill-Sachs lesion

Directory of Open Access Journals (Sweden)

Mayo Lee

2011-06-01

Full Text Available Abstract Background A Hill-Sachs lesion of the humeral head after a shoulder dislocation is clinically insignificant in most cases. However, a sizable defect will engage with the anterior rim of the glenoid and cause instability even after anterior glenoid reconstruction. The purpose of this study was to evaluate the outcome of arthroscopic capsulotenodesis of the posterior capsule and infraspinatus tendon ("remplissage" to seal a large engaging Hill-Sachs lesion in an unstable shoulder. Methods This was a prospective follow-up study of patients who underwent arthroscopic surgery for recurrent shoulder instability with a large engaging Hill-Sachs lesion from 2007 to 2009. The clinical results were measured preoperatively and postoperatively with the Simple Shoulder test (SST and the Rowe score for instability. Results Eleven patients met the inclusion criteria of this study. The mean follow-up time was 30 months (range 24 to 35 months. At the last follow-up, significant improvement was observed in both scores with no recurrent dislocations. The mean SST improved from 6.6 to 11 (p Conclusions Arthroscopic remplissage for shoulder instability is an effective soft tissue technique to seal a large engaging Hill-Sachs lesion with respect to recurrence rate, range of motion and shoulder function.

LITHOSTRATIGRAPHY AND SHEAR-WAVE VELOCITY IN THE CRYSTALLIZED TOPOPAH SPRING TUFF, YUCCA MOUNTAIN, NEVADA

International Nuclear Information System (INIS)

D. BUESCH; K.H. STOKOE; M. SCHUHEN

2006-01-01

Evaluation of the seismic response of the proposed spent nuclear fuel and high-level radioactive waste repository at Yucca Mountain, Nevada, is in part based on the seismic properties of the host rock, the 12.8-million-year-old Topopah Spring Tuff. Because of the processes that formed the tuff, the densely welded and crystallized part has three lithophysal and three nonlithophysal zones, and each zone has characteristic variations in lithostratigraphic features and structures of the rocks. Lithostratigraphic features include lithophysal cavities, rims on lithophysae and some fractures, spots (which are similar to rims but without an associated cavity or aperture), amounts of porosity resulting from welding, crystallization, and vapor-phase corrosion and mineralization, and fractures. Seismic properties, including shear-wave velocity (V s ), have been measured on 38 pieces of core, and there is a good ''first order'' correlation with the lithostratigraphic zones; for example, samples from nonlithophysal zones have larger V s values compared to samples from lithophysal zones. Some samples have V s values that are beyond the typical range for the lithostratigraphic zone; however, these samples typically have one or more fractures, ''large'' lithophysal cavities, or ''missing pieces'' relative to the sample size. Shear-wave velocity data measured in the tunnels have similar relations to lithophysal and nonlithophysal rocks; however, tunnel-based values are typically smaller than those measured in core resulting from increased lithophysae and fracturing effects. Variations in seismic properties such as V s data from small-scale samples (typical and ''flawed'' core) to larger scale traverses in the tunnels provide a basis for merging our understanding of the distributions of lithostratigraphic features (and zones) with a method to scale seismic properties

Summary of micrographic analysis of selected core samples from Well ER-20-6n number 1 in support of matrix diffusion testing

International Nuclear Information System (INIS)

1998-01-01

ER-20-6number s ign1 was cored to determine fracture and lithologic properties proximal to the BULLION test cavity. Selected samples from ER-20-6number s ign1 were subjected to matrix and/or fracture diffusion experiments to assess solute movement in this environment. Micrographic analysis of these samples suggests that the similarity in bulk chemical composition results in very similar mineral assemblages forming along natural fractures. These samples are all part of the mafic-poor Calico Hills Formation and exhibit fracture-coating mineral assemblages dominated by mixed illite/smectite clay and illite, with local opaline silica (2,236 and 2, 812 feet), and zeolite (at 2,236 feet). Based on this small sample population, the magnitude to which secondary phases have formed on fracture surfaces bears an apparently inverse relationship to the competency of the host lithology, reflected by variations in the degree of fracturing and the development of secondary phases on fracture surfaces. In the flow breccia at 2,851 feet, thinly developed, localized coatings are developed along persistent open fracture apertures in this competent rock type. Fractures in the devitrified lava from 2,812 feet are irregular, and locally blocked by secondary mineral phases. Natural fractures on the zeolitized tuff from 2,236 feet are discontinuous and irregular and typically obstructed with secondary mineral phases. There are also a second set of clean fractures in the 2,236 foot sample which lack secondary mineral phases and are interpreted to have been induced by the BULLION test. Based on these results, it is expected that matrix diffusion will be enhanced in samples where potentially transmissive fractures exhibit the greatest degree of obstruction (2,236>2,812=2,835>2,851). It is unclear what influence the induced fractures observed at 2,236 feet may have on diffusion given the lack of knowledge on their extent. It is assumed that the bulk matrix diffusion characteristics of the

Topographical Hill Shading Map Production Based Tianditu (map World)

Science.gov (United States)

Wang, C.; Zha, Z.; Tang, D.; Yang, J.

2018-04-01

TIANDITU (Map World) is the public version of National Platform for Common Geospatial Information Service, and the terrain service is an important channel for users on the platform. With the development of TIANDITU, topographical hill shading map production for providing and updating global terrain map on line becomes necessary for the characters of strong intuition, three-dimensional sense and aesthetic effect. As such, the terrain service of TIANDITU focuses on displaying the different scales of topographical data globally. And this paper mainly aims to research the method of topographical hill shading map production globally using DEM (Digital Elevation Model) data between the displaying scales about 1 : 140,000,000 to 1 : 4,000,000, corresponded the display level from 2 to 7 on TIANDITU website.

Soils of wet valleys in the Larsemann Hills and Vestfold Hills oases (Princess Elizabeth Land, East Antarctica)

Science.gov (United States)

Mergelov, N. S.

2014-09-01

The properties and spatial distribution of soils and soil-like bodies in valleys of the coastal Larsemann Hills and Vestfold Hills oases—poorly investigated in terms of the soil areas of East Antarctica—are discussed. In contrast to Dry Valleys—large continental oases of Western Antarctica—the studied territory is characterized by the presence of temporarily waterlogged sites in the valleys. It is argued that the deficit of water rather than the low temperature is the major limiting factor for the development of living organisms and the pedogenesis on loose substrates. The moisture gradients in the surface soil horizons explain the spatial distribution of the different soils and biotic complexes within the studied valleys. Despite the permanent water-logging of the deep suprapermafrost horizons of most of the soils in the valleys, no gley features have been identified in them. The soils of the wet valleys in the Larsemann Hills oasis do not contain carbonates. They have a slightly acid or neutral reaction. The organic carbon and nitrogen contents are mainly controlled by the amount of living and dead biomass rather than by the humic substances proper. The larger part of the biomass is concentrated inside the mineral soil matrix rather than on the soil surface. The stresses caused by surface drying, strong winds, and ultraviolet radiation prevent the development of organisms on the surface of the soil and necessitate the search for shelter within the soil fine earth material (endoedaphic niche) or under the gravelly pavement (hypolithic niche). In the absence of higher plants, humified products of their decomposition, and rainwater that can wash the soil profile and upon the low content of silt and clay particles in the soil material, "classical" soil horizons are not developed. The most distinct (and, often, the only diagnosed) products of pedogenesis in these soils are represented by organomineral films on the surface of mineral particles.

Scalar properties of transversely isotropic tuff from images of orthogonal cross sections

International Nuclear Information System (INIS)

Berge, P.A.; Berryman, J.G.; Blair, S.C.; Pena, C.

1997-01-01

Image processing methods have been used very effectively to estimate physical properties of isotropic porous earth materials such as sandstones. Anisotropic materials can also be analyzed in order to estimate their physical properties, but additional care and a larger number of well-chosen images of cross sections are required to obtain correct results. Although low-symmetry anisotropic media present difficulties for two-dimensional image processing methods, geologic materials are often transversely isotropic. Scalar properties of porous materials such as porosity and specific surface area can be determined with only minor changes in the analysis when the medium is transversely isotropic rather than isotropic. For example, in a rock that is transitively isotropic due to thin layers or beds, the overall porosity may be obtained by analyzing images of cross sections taken orthogonal to the bedding planes, whereas cross sections lying within the bedding planes will determine only the local porosity of the bed itself. It is known for translationally invariant anisotropic media that the overall specific surface area can be obtained from radial averages of the two-point correlation function in the full three-dimensional volume. Layered materials are not translationally invariant in the direction of the layering, but we show nevertheless how averages of cross sections may be used to obtain the specific surface area for a transversely isotropic rock. We report values of specific surface area obtained for thin sections of Topopah Spring Tuff from Yucca Mountain, Nevada. This formation is being evaluated as a potential host rock for geologic disposal of nuclear waste. Although the present work has made use of thin sections of tuff for the images, the same methods of analysis could also be used to simplify quantitative analysis of three-dimensional volumes of pore structure data obtained by means of x-ray microtomography or other methods, using only a few representative cross

Paleomagnetism and Anisotropy of Magnetic Susceptibility study of the Miocene Jack Springs Tuff (Nevada, USA)

Science.gov (United States)

Shields, S.; Petronis, M. S.; Pluhar, C. J.; Gordon, L.

2014-12-01

The mid-Miocene Jack Springs Tuff (JST) outcrops across the western Mina Deflection accommodation zone, west-central Nevada and into eastern California. Previously, the source location for the JST was unknown, yet recent studies northwest of Mono Lake, CA have identified a relatively un-rotated structural block in which to reference the paleomagnetic data. Although new studies have indicated that this block may be rotated up to 13º, we argue that the probable source area is located near the Bodie Hills, CA. At this site, the paleomagnetic reference direction is D = 353°, I = 43°, α95 = 7.7° (Carlson et al, 2013). Based on these data, the JST can be used to measure absolute vertical-axis rotation as well as enable reconstruction of the paleo-topography using the corrected anisotropy of magnetic susceptibility (AMS) data. A total of 19 sites were sampled to constrain Cenozoic to recent vertical axis rotation within the region and AMS experiments were conducted to determine the flow direction of the JST. Curie point estimates indicate that the JST ranges in titanium concentration from 0.042 to 1.10, indicating a low to moderate titanomagnetite phase (Akimoto, 1962). Demagnetization experiments reveal mean destructive fields of the NRM ranging between 15mT and 40mT suggesting that both multi-domain to pseudo-single domain grains are the dominant ferromagnetic phases that carry the remanence and AMS fabric. Preliminary paleomagnetic data yield stable single component demagnetization behavior for most sites that, after structural correction, indicate clockwise vertical axis rotation ranging from +20°± 10° to +60°± 11° between multiple fault blocks. The uncorrected AMS data yield oblate magnetic fabrics that can be used to infer the transport direction, source region, and paleovalley geometry of the JST. These data are tentatively interpreted to indicate west to east transport of the JST across the Mono Basin region into the Mina Deflection that was erupted and

Calibration of neutron moisture gauges and their ability to spatially determine soil water content in environmental studies

International Nuclear Information System (INIS)

Nyhan, J.W.; Martinez, J.L.; Langhorst, G.J.

1994-10-01

Several neutron moisture gauges were calibrated, and their ability to spatially determine soil water content was evaluated. In 1982, the midpoint of sensitivity of each neutron probe to the detection of hydrogen was determined, as well as the radius of investigation of each probe in crushed Bandelier Tuff with varying water contents. After determining the response of one of the moisture gauges to changes in soil water at the soil-air interface, a neutron transport model was successfully calibrated to predict spatial variations in soil water content. The model was then used to predict various shapes and volumes of crushed Bandelier Tuff interrogated by the neutron moisture gauge. From 1991 through 1994, six neutron moisture gauges were calibrated for soil water determinations in a local topsoil and crushed Bandelier Tuff, as well as for a sample of fine sand and soils from a field experiment at Hill Air Force Base. Statistical analysis of the calibration results is presented and summarized, and a final summary of practical implications for future neutron moisture gauge studies at Los Alamos is included

Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

Science.gov (United States)

Török, Ákos; Barsi, Árpád; Bögöly, Gyula; Lovas, Tamás; Somogyi, Árpád; Görög, Péter

2018-02-01

Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE-WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).

Three-dimensional computed tomography measurement accuracy of varying Hill-Sachs lesion size.

Science.gov (United States)

Ho, Anthony; Kurdziel, Michael D; Koueiter, Denise M; Wiater, J Michael

2018-02-01

The glenoid track concept has been proposed to correlate shoulder stability with bone loss. Accurate assessment of Hill-Sachs lesion size preoperatively may affect surgical planning and postoperative outcomes; however, no measurement method has been universally accepted. This study aimed to assess the accuracy and reliability of measuring Hill-Sachs lesion sizes using 3-dimensional (3D) computed tomography (CT). Nine polyurethane humerus bone substitutes were used to create Hill-Sachs lesions of varying sizes with a combination of lesion depth (shallow, intermediate, and deep) and width (small, medium, and large). Specimens were scanned with a clinical CT scanner for size measurements and a micro-CT scanner for measurement of true lesion size. Six evaluators repeated measurements twice in a 2-week interval. Scans were measured by use of 3D CT reconstructions for length, width, and Hill-Sachs interval and with use of 2D CT for depth. The interclass correlation coefficient evaluated interobserver and intraobserver variability and percentage error, and Student t-tests assessed measurement accuracy. Interclass correlation coefficient reliability demonstrated strong agreement for all variables measured (0.856-0.975). Percentage error between measured length and measured depth and the true measurement significantly varied with respect to both lesion depth (P = .003 and P = .005, respectively) and lesion size (P = .049 and P = .004, respectively). The 3D CT imaging is effective and reproducible in determining lesion size. Determination of Hill-Sachs interval width is also reliable when it is applied to the glenoid track concept. Measured values on 3D and 2-dimensional imaging using a conventional CT scanner may slightly underestimate true measurements. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Assessment of Groundwater Resources in Kirana Hills Region, Rabwah, District Chiniot, Pakistan

Directory of Open Access Journals (Sweden)

Mirza Naseer Ahmad

2016-12-01

Full Text Available This study was planned to assess the groundwater quality of the area adjacent to Precambrian Kirana Hills, Pakistan. The majority of the people in the area use groundwater from private wells for drinking and domestic use. Therefore, it is important to provide an overview of the groundwater quality. This information would be beneficial to local people and the administration for selecting suitable water treatment methods. Samples were collected from different wells of Rabwah town, close to the Kirana Hills. Parameters like EC, pH, alkalinity and total dissolved solids (TDS were determined for 142 samples. While 40 samples were analyzed for hardness, Ca, Mg, Cl, SO4, NO3, and F. standards set by the World Health Organization (WHO were considered to evaluate the quality of groundwater. Geographic Information System (GIS was used to interpolate analyzed physicochemical parameters. The results showed that EC, TDS, hardness, Cl, SO4, and Ca were very high in the water samples of the area. Fifty-two percent of samples had pH values lower than the permissible limits. Results suggest that the water quality is extremely adverse close to the hills. The poor water quality in the area near the hills may be due to the limited recharge of aquifers because of the hills and shallow basement, which may act as a barrier to subsurface water movement. Some physical and chemical parameters indicated that the quality of water at deeper levels (i.e. >150 ft is relatively better. This may be due to limited exploitation of water from deeper aquifers as compared to shallow aquifers. Hence, proper aquifer management is required to prevent water quality deterioration due to over exploiataion. NO3 was found within the acceptable limits and all water samples were found free of any significant contamination by human activities.

78 FR 21098 - Black Hills National Forest Advisory Board

Science.gov (United States)

2013-04-09

... Hills National Forest Advisory Board (Board) will meet in Rapid City South Dakota. The Board is... staff before the meeting. The agenda will include time for people to make oral statements of three...

Stormwater Management Plan for the Arden Hills Army Training Site, Arden Hills, Minnesota

Energy Technology Data Exchange (ETDEWEB)

Carr, Adrianne E. [Argonne National Lab. (ANL), Argonne, IL (United States); Wuthrich, Kelsey K. [Argonne National Lab. (ANL), Argonne, IL (United States); Ziech, Angela M. [Argonne National Lab. (ANL), Argonne, IL (United States); Bowen, Esther E. [Argonne National Lab. (ANL), Argonne, IL (United States); Quinn, John [Argonne National Lab. (ANL), Argonne, IL (United States)

2013-03-01

This stormwater management plan focuses on the cantonment and training areas of the Arden Hills Army Training Site (AHATS). The plan relates the site stormwater to the regulatory framework, and it summarizes best management practices to aide site managers in promoting clean site runoff. It includes documentation for a newly developed, detailed model of stormwater flow retention for the entire AHATS property and adjacent upgradient areas. The model relies on established modeling codes integrated in a U.S. Department of Defense-sponsored software tool, the Watershed Modeling System (WMS), and it can be updated with data on changes in land use or with monitoring data.

New type of hill-top inflation

Energy Technology Data Exchange (ETDEWEB)

Barvinsky, A.O.; Nesterov, D.V. [Theory Department, Lebedev Physics Institute, Leninsky Prospect 53, Moscow 119991 (Russian Federation); Kamenshchik, A.Yu., E-mail: barvin@td.lpi.ru, E-mail: Alexander.Kamenshchik@bo.infn.it, E-mail: nesterov@td.lpi.ru [Dipartimento di Fisica and INFN, via Irnerio 46, 40126 Bologna (Italy)

2016-01-01

We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters ε and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R{sup 2}-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

New type of hill-top inflation

Energy Technology Data Exchange (ETDEWEB)

Barvinsky, A.O. [Theory Department, Lebedev Physics Institute,Leninsky Prospect 53, Moscow 119991 (Russian Federation); Department of Physics, Tomsk State University,Lenin Ave. 36, Tomsk 634050 (Russian Federation); Department of Physics and Astronomy, Pacific Institue for Theoretical Physics,University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Kamenshchik, A.Yu. [Dipartimento di Fisica and INFN,via Irnerio 46, 40126 Bologna (Italy); L.D. Landau Institute for Theoretical Physcis,Kosygin str. 2, 119334 Moscow (Russian Federation); Nesterov, D.V. [Theory Department, Lebedev Physics Institute,Leninsky Prospect 53, Moscow 119991 (Russian Federation)

2016-01-20

We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters ϵ and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R{sup 2}-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

The hill forts and castle mounds in Lithuania: interaction between geodiversity and human-shaped landscape

Science.gov (United States)

Skridlaite, Grazina; Guobyte, Rimante; Satkunas, Jonas

2015-04-01

Lithuania is famous for its abundant, picturesque hill forts and castle mounds of natural origin. In Lithuania as well as in whole Europe the fortified hills were used as the society dwelling place since the beginning of the Late Bronze Age. Their importance increased when Livonian and Teutonic Orders directed a series of military campaigns against Lithuania with the aim of expansion of Christianity in the region at the end of 1st millennium AD, and they were intensively used till the beginning of the 15th c. when most of them were burned down during fights with the Orders or just abandoned due to the changing political and economical situation. What types of the geodiversity were used for fortified dwellings? The choice in a particular area depended on a variety of geomorphology left behind the retreating ice sheets. High spots dominating their surroundings were of prime interest. In E and SE Lithuania, the Baltic Upland hills marking the eastern margin of the last Weichselian glacier hosted numerous fortified settlements from the end of 2nd millennium BC to the Medieval Ages (Narkunai, Velikuskes etc). In W Lithuania, plateau-like hills of the insular Samogitian Upland had been repeatedly fortified from the beginning of 1st millennium AD to the 14th century (Satrija, Medvegalis etc). Chains of hill forts and castle mounds feature the slopes of glaciofluvial valleys of Nemunas, Neris and other rivers where the slopes were dissected by affluent rivulets and ravines and transformed into isolated, well protected hills (Kernave, Punia, Veliuona etc). Peninsulas and headlands formed by the erosion of fluvial and lacustrine deposits were used in the lowlands, e.g. in central and N Lithuania (Paberze, Mezotne etc). How much the landscape was modified for defense purposes? Long-term erosion and overgrowing vegetation damaged the former fortified sites, however some remains and the archeological excavations allowed their reconstruction. The fortified Bronze Age settlements

A power function profile of a ski jumping in-run hill.

Science.gov (United States)

Zanevskyy, Ihor

2011-01-01

The aim of the research was to find a function of the curvilinear segment profile which could make possible to avoid an instantaneous increasing of a curvature and to replace a circle arc segment on the in-run of a ski jump without any correction of the angles of inclination and the length of the straight-line segments. The methods of analytical geometry and trigonometry were used to calculate an optimal in-run hill profile. There were two fundamental conditions of the model: smooth borders between a curvilinear segment and straight-line segments of an in-run hill and concave of the curvilinear segment. Within the framework of this model, the problem has been solved with a reasonable precision. Four functions of a curvilinear segment profile of the in-run hill were investigated: circle arc, inclined quadratic parabola, inclined cubic parabola, and power function. The application of a power function to the in-run profile satisfies equal conditions for replacing a circle arc segment. Geometrical parameters of 38 modern ski jumps were investigated using the methods proposed.

Hill climbing algorithms and trivium

DEFF Research Database (Denmark)

Borghoff, Julia; Knudsen, Lars Ramkilde; Matusiewicz, Krystian

2011-01-01

This paper proposes a new method to solve certain classes of systems of multivariate equations over the binary field and its cryptanalytical applications. We show how heuristic optimization methods such as hill climbing algorithms can be relevant to solving systems of multivariate equations....... A characteristic of equation systems that may be efficiently solvable by the means of such algorithms is provided. As an example, we investigate equation systems induced by the problem of recovering the internal state of the stream cipher Trivium. We propose an improved variant of the simulated annealing method...

Fuel management optimization in pressure water reactors with hexagonal geometry using hill climbing method

International Nuclear Information System (INIS)

Andres Diaz, J.; Quintero, Ruben; Melian, Manuel; Rosete, Alejandro

2000-01-01

In this work the general-purpose optimization method, Hill Climbing, was applied to the Fuel Management Optimization problem in PWR reactors, WWER type. They were carried out a series of experiments in order to study the performance of Hill Climbing. It was proven two starting point for initialize the search: a reload configuration by project and a reload configuration generated with the application of a minimal knowledge of the problem. It was also studied the effect of imposing constraints based on the physics of the reactor in order to reduce the number of possible solutions to be generated. The operator used in Hill Climbing was defined as a binary exchange of fuel assemblies. For the simulation of each generated configuration, the tridimensional simulator program SPPS-1 was used. It was formulated an objective function with power peaking constraint to guide the search. As results, a methodology ws proposed for the In-core Fuel Management Optimization in hexagonal geometry, and the feasibility of the application of the Hill Climbing to this type of problem was demonstrated. (author)

Predicting spent fuel oxidation states in a tuff repository

International Nuclear Information System (INIS)

Einziger, R.E.; Woodley, R.E.

1987-01-01

Nevada Nuclear Waste Storage Investigations Project (NNWSI) is studying the suitability of the tuffaceous rocks at Yucca Mountain as a waste repository for spent fuel disposal. The oxidation state of the LWR spent fuel in the moist air environment of a tuff repository could be a significant factor in determining its leaching and dissolution characteristics. Predictions as to which oxidation states would be present are important in analyzing such a repository and thus the present study was undertaken. A set of TGA (thermogravimetric analysis) tests were conducted on well-controlled samples of irradiated PWR fuel with time and temperature as the only variables. The tests were conducted between 140 and 225 0 C for a duration up to 2200 hours. The weight gain curves were analyzed in terms of diffusion through a layer of U 3 O 7 , diffusion into the grains to form a solid solution, a simplified empirical representation of a combination of grain boundary diffusion and bulk grain oxidation. Reaction rate constants were determined in each case, but analysis of these data could not establish a definitive mechanism. 21 refs., 10 figs., 3 tabs

Evaluation of past and future alterations in tuff at Yucca Mountain, Nevada, based on the clay mineralogy of drill cores USW G-1, G-2, and G-3

International Nuclear Information System (INIS)

Bish, D.L.

1989-03-01

The tuffs at Yucca Mountain in south-central Nevada are being studied by the Yucca Mountain Project (YMP) to determine their suitability for a high-level radioactive waste repository. For predictive purposes, it is important to understand the alteration history of Yucca Mountain and to know how the minerals in Yucca Mountain tuffs respond to changing conditions such as elevated temperatures. The clay mineralogy of these tuffs has been examined using x-ray powder diffraction, and approximation temperatures of alteration have been determined using available clay mineral data and fluid inclusion analyses. Also, several illites from drill holes USW G-1 and G-2 have been dated using K/Ar techniques, yielding ages of about 11 Myr. The clay mineral in Yucca Mountain tuffs are predominantly interstratified illite/smectites, with minor amounts of chloride, kaolinite, and interstratified chlorite/smectite at depth in USW G-1 and G-2. The reactions observed for these illite/smectites are similar to those observed in pelitic rocks. With depths, the illite/smectites transform from random interstratifications (R = 0) through ordered intermediates (R = 1) to illite in USW G-2 and to Kalkberg (R ≥ 3) interstratifications in USW G-1. The illite/smectites in USW G-3 have not significantly transformed. It appears that the illites in deeper rock results from hydrothermal and diagenetic reactions of earlier-formed smectites. These data demonstrate that the rocks at depth in the northern end of Yucca Mountain were significantly altered about 11 Myr ago. Both clay mineralogy and fluid inclusions suggest that the rocks at depth in USW G-2 have been subjected to postdepositional temperatures of at least 275/degree/C, those in USW G-1 have reached 200/degree/C, and USW G-3 rocks probably have not exceeded 100/degree/C. 64 refs., 9 figs., 3 tabs

Dental disease control in Pine Hill, New Mexico.

Science.gov (United States)

Carberry, Frank J; Cloud, Bill; Finster, Carolyn

2004-02-01

One-year results of a community-operated dental disease control project in Pine Hill, New Mexico. The program uses fluoride, chiefly rinse, and has not only reduced the amount of decay in permanent teeth, but has markedly reduced the need for restorative care of primary teeth.

Environmental protection and regulatory compliance at the Elk Hills field

International Nuclear Information System (INIS)

Chappelle, H.H.; Donahoe, R.L.; Kato, T.T.; Ordway, H.E.

1991-01-01

Environmental protection has played an integral role in the development and operation of the Elk Hills field since production at the maximum efficient rate was authorized in 1976. The field is located in a non-attainment area for California and National Ambient Air Quality Standards for two criteria pollutants and their associated precursors, is home to four endangered species, and operates within the California regulatory framework. Environmental protection and regulatory compliance is a multi-faceted program carried out through a substantial commitment of resources and workforce involvement. This paper describes the actions taken and resources employed to protect the environment, specific technologies and projects implemented, and the ongoing nature of these efforts at Elk Hills

One-Way Nested Large-Eddy Simulation over the Askervein Hill

Directory of Open Access Journals (Sweden)

James D. Doyle

2009-07-01

Full Text Available Large-eddy simulation (LES models have been used extensively to study atmospheric boundary layer turbulence over flat surfaces; however, LES applications over topography are less common. We evaluate the ability of an existing model – COAMPS^®-LES – to simulate flow over terrain using data from the Askervein Hill Project. A new approach is suggested for the treatment of the lateral boundaries using one-way grid nesting. LES wind profile and speed-up are compared with observations at various locations around the hill. The COAMPS-LES model performs generally well. This case could serve as a useful benchmark for evaluating LES models for applications over topography.

Stochastic modeling and simulation of reaction-diffusion system with Hill function dynamics.

Science.gov (United States)

Chen, Minghan; Li, Fei; Wang, Shuo; Cao, Young

2017-03-14

Stochastic simulation of reaction-diffusion systems presents great challenges for spatiotemporal biological modeling and simulation. One widely used framework for stochastic simulation of reaction-diffusion systems is reaction diffusion master equation (RDME). Previous studies have discovered that for the RDME, when discretization size approaches zero, reaction time for bimolecular reactions in high dimensional domains tends to infinity. In this paper, we demonstrate that in the 1D domain, highly nonlinear reaction dynamics given by Hill function may also have dramatic change when discretization size is smaller than a critical value. Moreover, we discuss methods to avoid this problem: smoothing over space, fixed length smoothing over space and a hybrid method. Our analysis reveals that the switch-like Hill dynamics reduces to a linear function of discretization size when the discretization size is small enough. The three proposed methods could correctly (under certain precision) simulate Hill function dynamics in the microscopic RDME system.

Radiometric evidence of Middle Devonian inversion of the Hill End Trough, northeast Lachlan Fold Belt

International Nuclear Information System (INIS)

Pakham, G.H.

1999-01-01

The publication of a new geological time-scale by the Australian Geological Survey Organisation and radiometric dates from the Hill End goldfield have prompted the re-examination of the timing of deformation of the Hill End Trough to determine whether it occurred in Middle Devonian or Early Carboniferous time. Palaeontological evidence from the western trough margin and the Capertee High dates the end of deposition in the trough as late Emsian or early Eifelian (385-382 Ma). After a mid-Devonian hiatus of at least 15 million years, paralic sedimentation commenced on the Molong and Capertee Highs in late Frasnian or early Famennian time (367-363 Ma). No Upper Devonian sedimentary formations occur in the Hill End Trough. Structural relationships indicate that the oldest mineral veins at Hill End preceded cleavage formation in the deformed trough sedimentary rocks. Early vein muscovites have Middle Devonian 40 Ar/ 39 Ar dates of 380-370 Ma. Regional metamorphic biotites from Hill End have well constrained 40 Ar/ 39 Ar closing ages of 360-358 Ma (mid-Famennian). The metamorphic (thermal) maximum which outlasted penetrative deformation. is estimated here by modelling to have been about 370 Ma (latest Givetian). This clearly places the earlier main deformation in the Middle Devonian. Deformation probably began by terminating trough deposition in latest Emsian to early Eifelian time and ended in early Givetian time at about 375 Ma ago. Published pressure and temperature data from the Hill End goldfield suggest that deformation thickened the 6 km sediment column to around 11 km. The thermal model suggests there was post-deformation erosion of about 4km and little if any further erosion occurred during Late Devonian to Early Carboniferous time. The shortening accompanying the inversion of the northern Hill End Trough may have been taken up in the region to the south, both east and west of the Copperhannia Thrust, and east of the southern termination of the Capertee High

HILL: The High-Intensity Laser Laboratory Core Team's Reply to Questions from the NNSA Experimental Facilities Panel

International Nuclear Information System (INIS)

Albright, B.J.

2012-01-01

Question 1 - The type of physics regimes that HILL can access for weapons studies is quite interesting. The question that arises for the proposal team is what priority does this type of experimental data have versus data that can be obtained with NIF, and Z. How does HILL rank in priority compared to MARIE 1.0 in terms of the experimental data it will provide? We reiterate that isochoric heating experiments to be conducted with HILL are complementary to the high energy density physics experiments at NIF and Z and uniquely access states of matter that neither other facility can access. It is our belief that HILL will enable several important questions, e.g., as related to mix morphology, radiation transfer from corrugated surfaces, and equations of state, to be run to ground through carefully diagnosed, 'unit-physics' experiments. Such experiments will substantially improve confidence in our computer models and provide a rigorous science basis for certification. Question 2 - A secondary question relates to the interests of LLNL and SNL in the physics that HILL can address. This should be spelled out clearly. I would like to see the other labs be part of the discussion regarding how important this capability would be if built. Both sister Labs have a keen interest in the physics enabled by high-intensity, high-energy lasers, as evinced by the Z Petawatt and NIF ARC upgrades to their signature facilities. LANL scientists have teamed with scientists from both Laboratories in high-intensity laser 'first experiments' envisioned for HILL and we fully intend to continue these profitable discussions going forward. In the preparation of the HILL proposal, feedback was solicited from the broader HEDP and weapons science communities. The consensus view was that HILL filled a critical gap and that there was a need for a facility like HILL to address outstanding questions in weapons science. It was recognized that co-location of HILL with a facility such as MaRIE 1.0, Z, NIF, or

Geologic map of the Bodie Hills, California and Nevada

Science.gov (United States)

John, David A.; du Bray, Edward A.; Box, Stephen E.; Vikre, Peter G.; Rytuba, James J.; Fleck, Robert J.; Moring, Barry C.

2015-01-01

The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). Upper Miocene to Pliocene sedimentary deposits, mostly basin-filling sediments, gravel deposits, and fanglomerates, lap onto the west, north, and east sides of the Bodie Hills, where they cover older Miocene volcanic rocks. Quaternary surficial deposits, including extensive colluvial, fluvial, glacial, and lacustrine deposits, locally cover all older rocks. Miocene and younger rocks are tilted ≤30° in variable directions. These rocks are cut by several sets of high-angle faults that exhibit a temporal change from conjugate northeast-striking left-lateral and north-striking right-lateral oblique-slip faults in rocks older than about 9 Ma to north- and northwest-striking dip-slip faults in late Miocene rocks. The youngest faults are north-striking normal and northeast-striking left-lateral oblique-slip faults that cut Pliocene-Pleistocene rocks. Numerous hydrothermal systems were active during Miocene magmatism and formed extensive zones of hydrothermally altered rocks and several large mineral deposits, including gold- and silver-rich veins in the Bodie and Aurora mining districts (Vikre and others, in press).

Comparison of Genetic Algorithm and Hill Climbing for Shortest Path Optimization Mapping

Directory of Open Access Journals (Sweden)

Fronita Mona

2018-01-01

Full Text Available Traveling Salesman Problem (TSP is an optimization to find the shortest path to reach several destinations in one trip without passing through the same city and back again to the early departure city, the process is applied to the delivery systems. This comparison is done using two methods, namely optimization genetic algorithm and hill climbing. Hill Climbing works by directly selecting a new path that is exchanged with the neighbour’s to get the track distance smaller than the previous track, without testing. Genetic algorithms depend on the input parameters, they are the number of population, the probability of crossover, mutation probability and the number of generations. To simplify the process of determining the shortest path supported by the development of software that uses the google map API. Tests carried out as much as 20 times with the number of city 8, 16, 24 and 32 to see which method is optimal in terms of distance and time computation. Based on experiments conducted with a number of cities 3, 4, 5 and 6 producing the same value and optimal distance for the genetic algorithm and hill climbing, the value of this distance begins to differ with the number of city 7. The overall results shows that these tests, hill climbing are more optimal to number of small cities and the number of cities over 30 optimized using genetic algorithms.

Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

Directory of Open Access Journals (Sweden)

Á. Török

2018-02-01

Full Text Available Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System was used to collect images which were processed by Pix4D mapper (structure from motion technology to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS with the use of seven ground control points. The obtained digital surface model (DSM was processed (vegetation removal and the derived digital terrain model (DTM allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method. Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE–WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS.

Deformation and velocity measurements at elevated temperature in a fractured 0.5 M block of tuff

International Nuclear Information System (INIS)

Blair, S.C.; Berge, P.A.

1996-01-01

This paper presents preliminary results of laboratory tests conducted on small block samples of Topopah Spring tuff, in support of the Yucca Mountain Site Characterization Project. The overall objective of these tests is to investigate the thermal-mechanical, thermal-hydrological, and thermal-chemical response of the rock to conditions similar to the near-field environment (NFE) of a potential nuclear waste repository. We present preliminary results of deformation and elastic wave velocity measurements on a 0.5-m-scale block of Topopah Spring tuff tested in uniaxial compression to 8.5 MPa and at temperatures to 85 degree C. The Young's modulus was found to be about 7 to 31 GPa for vertical measurements parallel to the stress direction across parts of the block containing no fractures or a few fractures, and 0.5 to 0.9 GPA for measurements across individual fractures, at ambient temperature and 8.5 MPa maximum stress. During stress cycles between 5 and 8.5 MPa, the deformation modulus values for the matrix with fractures were near 15-20 GPa at ambient temperature but dropped to about 10 GPa at 85 degree C. Compressional wave velocities were found to be about 3.6 to 4.7 km/s at ambient temperature and stress. After the stress was cycled, velocities dropped to values as low as 2.6 km/s in the south end of the block where vertical cracks developed. Heating the block to about 85 degree C raised velocities to as much as 5.6 km/s in the upper third of the block

Laboratory measurement of permeability upscaling: Results for the Topopah Spring Member of the Paintbrush Tuff

International Nuclear Information System (INIS)

Tidwell, V.C.; Wilson, J.L.

1997-01-01

Parameterization of predictive models is often complicated by the inability to make measurements at the same scale at which one wishes to perform the analysis. This disparity in scales necessitates the use of some averaging or upscaling model to compute the desired effective media properties. In efforts to better model permeability upscaling, laboratory experiments have been conducted on a series of rock samples with different genetic origins. These experiments involve the collection of exhaustive permeability data sets at different sample supports (i.e., sample volumes) using a specially designed minipermeameter test system. Here the authors present a synopsis of such a data set collected from a block of volcanic tuff

Meteorological observations in support of a hill cap cloud experiment

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Morten

1998-06-01

Humid air flows form a hill cap cloud over the Agana mountain ridge in the north-east of Tenerife. The HILLCLOUD project utilised this cloud formation to investigate the chemical and physical properties of cloud aerosols by land based observations. The project was part of the second Aerosol characterisation Experiment (ACE-2) of the International Global Atmospheric chemistry project (IGAC). The present report describes meteorological observations in support of the hill cap cloud experiment. Time-series of wind speed, wind direction, temperature and humidity were collected at ground-based meteorological stations during a period starting one year in advance of the main campaign. A series of radiosonde detecting the upstream stability and wind profile were launched during the main campaign. (au) 5 tabs., 32 ills., 6 refs.

Corrosion testing of a degraded moderator: L-Area Tuff Tanks

International Nuclear Information System (INIS)

Mickalonis, J.I.

2000-01-01

Based on test results, storage of the degraded moderator in 55-gallon 304L drums (0.065 inches thick) would not cause failure by general corrosion for up to 5 plus years storage. Acidic degraded moderator was temporarily stored in Tuff Tanks located in L-area. The moderator characteristics included a D 2 O content of 5.02--5.33%, a pH of 1.25--1.31, a conductivity of 29,300--31,200 m mhos/cm, tritium activity of 114--141 m Ci/mL, and levels of approximately 6,000 ppm for chloride and 500 ppm for chromium. The compatibility of the degraded with AISI Type 304L stainless steel (304L) was investigated in this study. Following ASTM standard practice, coupon immersion tests were conducted in both treated and untreated moderator. Treatment included the addition of either a 40 wt % NaOH solution, distilled water to serially dilute the chloride, or concentrated nitric acid to increase the nitrate concentration. Type 304L stainless steel exposed to the Tuff Tank moderator was found from these tests to: have a general corrosion rate of less than 5 mils per year (mpy) for 304L plate, which bounds that of the 304L storage drum, passivate at chloride concentrations up to 5,000 ppm for 304L sheet, resist corrosion for nitrate/chloride ratios ranging from 0.1 to 1,000, and be susceptible to crevice corrosion. Based on these test results, storage of the degraded moderator in 55-gallon 304L drums (0.065 inch thick) would not cause failure by general corrosion for up to 5+ years storage. The chloride concentration, [Cl], in the degraded moderator has been measured up to 6000 ppm. The potential or risk for aggressive localized attack of 304L increases with [Cl] concentration. A qualitative range is as follows: [Cl minus ] minus ] minus ] < 600 ppm, reasonable resistance, medium risk. The degraded moderator should be treated to reduce the chloride concentration to reduce the potential for localized corrosion and the risk for a leakage failure of the drum. A good practice would be to

Geochronology, stratigraphy and geochemistry of Cindery Tuff in Pliocene hominid-bearing sediments of the Middle Awash, Ethiopia.

Science.gov (United States)

Hall, C M; Walter, R C; Westgate, J A; York, D

Cindery Tuff is a subalkaline, rhyolitic air-fall deposit that was probably produced by a mixed-magma eruption. It is a distinctive, datable, regional isochronous marker bed within the Pliocene sediments of the Middle Awash district, and is stratigraphically situated between two new fossil hominid discoveries. Based on 40Ar/39Ar analyses of plagioclase, rhyolitic glass and basaltic glass, as well as fission-track analyses of zircons, we estimate its age to be 3.8-4.0 Myr. This implies that associated hominid skull fragments are at least 3.9 Myr old.

Calculation of experiment uncertainty in laboratory determination of several geoengineering properties of tuffs from Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Nimick, F.B.; Schwartz, B.M.; Price, R.H.

1991-11-01

A method for estimating the precision and accuracy of measured parameters is described. Examples of application of the estimating method are presented for density, porosity, compressive strength, Young's modulus, Poisson's ratio, and thermal expansion. With the exception of the coefficient of linear thermal expansion, all laboratory data for these properties for tuff samples appear to have reasonable experiment uncertainties. Uncertainties in the thermal-expansion coefficients may be as high as 39% of the values, although most uncertainties for the coefficients are probably ≤2%. 4 refs., 1 fig., 15 tabs

Stratigraphy and paleontology of fossil hill Peninsula Fildes, Rey Jorge island, Antarctica: a new approach

International Nuclear Information System (INIS)

Perea, D.; Masquelin, H.; Verde, M.; Guerequiz, R.

1998-01-01

Results of the first Uruguayan paleontologic and biostratigraphical investigations in Antarctica are presented.The field work was performed in Fildes Peninsula, King George Island, near the Uruguayan station Base Cientifica Antartida Artigas. Some fossiliferous outcrops were geologic and pale ontologically analyzed, among them the Fossil Hill, placed in the middle part of the peninsula, in front of Ardley Island between the Chinese and Chilean stations. This hill is composed of fossil bearing piroclastic and epiclastic rocks, assigned to the Fossil Hill Fm.Vegetal remains (petrified wood and leaf impronts)were observed and collected in this unit and it is remarkable the presence of Nothofagus sp. and invertebrate trace fossils Cochlichnus isp and Helminthopsis isp.

Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust

Science.gov (United States)

Ushikubo, Takayuki; Kita, Noriko T.; Cavosie, Aaron J.; Wilde, Simon A.; Rudnick, Roberta L.; Valley, John W.

2008-08-01

In situ Li analyses of 4348 to 3362 Ma detrital zircons from the Jack Hills, Western Australia by SIMS reveal that the Li abundances (typically 10 to 60 ppm) are commonly over 10,000 times higher than in zircons crystallized from mantle-derived magmas and in mantle-derived zircon megacrysts (typically Jack Hills zircons also have fractionated lithium isotope ratios ( δ7Li = - 19 to + 13‰) about five times more variable than those recorded in primitive ocean floor basalts (2 to 8‰), but similar to continental crust and its weathering products. Values of δ7Li below - 10‰ are found in zircons that formed as early as 4300 Ma. The high Li compositions indicate that primitive magmas were not the source of Jack Hills zircons and the fractionated values of δ7Li suggest that highly weathered regolith was sampled by these early Archean magmas. These new Li data provide evidence that the parent magmas of ancient zircons from Jack Hills incorporated materials from the surface of the Earth that interacted at low temperature with liquid water. These data support the hypothesis that continental-type crust and oceans existed by 4300 Ma, within 250 million years of the formation of Earth and the low values of δ7Li suggest that weathering was extensive in the early Archean.

ACCOMMODATION INFRASTRUCTURE AND TOURISM FLOWS ON FELEACU HILL (CLUJ COUNTY

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DANIELA-LIVIA GHEORGHIEȘ

2016-06-01

Full Text Available Accommodation Infrastructure and Tourism Flows on Feleacu Hill (Cluj County. Feleacu Hill experienced tourism development between 2001 and 2015. The INS data indicates that the number of accommodation units increased from one (2001 to four (2015 and there are a few more which are not registered in the INS database. The accommodation capacity increases, as many guesthouses are expanding their premises to receive more tourists and new accommodation units emerge, such as Hotel Premier in Vâlcele (Feleacu commune. Tourism flows also registered a highly positive trend. The number of arrivals increased from 95 tourists in 2002 to 7791 tourists in 2015. However, there was a downturn between 2009 and 2012, due to the economic crisis and the opening of the Turda – Gilău motorway (A3, which redirected transit routes outside the region and led to the closure of Paradis Hotel in 2012. Since 2012, the number of arrivals and overnight stays increased steadily due to the development of new forms of tourism – rural tourism, agrotourism, extreme tourism and complex tourism, materialized in growing numbers of tourists at the two guesthouses in Ciurila commune (“La Mesteceni” and “Domeniul Regilor”. Tourism brings obvious benefits to the rural communities on Feleacu Hill, even if the average duration of stay is still low.

Sources of Fe in eolian and soil detritus at Yucca Mountain, Nevada, USA

International Nuclear Information System (INIS)

Vaniman, D.; Chipera, S.; Bish, D.

1997-01-01

Eolian deposits and adjacent soil horizons at Exile Hill near Yucca Mountain, Nevada, provide a desert environment where the origins of exotic eolian materials can be discerned. Petrographic, chemical, X-ray diffraction, and electron microprobe data allow an assessment of Fe mineral sources. Fe-rich minerals in local rhyolitic tuff bedrock consist of distinctive biotite and amphibole phenocrysts and groundmass Mn-hematites. Although the local tuffs contain only 1% FeO, detrital components of eolian and soil deposits have ∼3% FeO. Exotic minerals from distant sources provide most of the excess Fe in the surficial deposits. The exotic Fe sources are principally smectite, low-Mn hematite, low-F biotite, and high-Fe amphibole not found in local tuffs. Iron contents and the exotic Fe fraction increase with decreasing grain size, such that the clay fractions have ∼5--6% FeO, almost all of which is in exotic smectites. The distant origin of these smectites is evident in their high Fe content and distinct Sc/FeO enrichment trends, which differ from the strong local Sc/FeO control defined by coarser soil detritus. Approximate crustal average lanthanide composition in soil and eolian smectites rule out any significant contribution of local smectite derived from tuff alteration. The eolian and soil smectites instead inherit their high Fe content from eolian biotite

The proterozoic Georgetown Province - a Broken Hill analogue

International Nuclear Information System (INIS)

Carr, G.R.

2000-01-01

Collaborative work between CSIRO and AGSO has resulted in the development of a Pb isotope model that attempts to place relatively precise (∼5 Ma) age constraints on Proterozoic mineralisation in the Mount Isa and McArthur River terrains (Sun et al., 1994). Although this model was developed for sediment hosted mineralisation in low grade metamorphic terrains, the CSIRO-AGSO model ages for other mineralisation in high-grade terrains such as Broken Hill appear to be consistent with the U-Pb zircon ages obtained for the high-grade host sequences. Without independent evidence that the model is applicable to such terrains, the observations cannot be used to indicate the age of the mineralisation. Lead isotope data obtained on potassium feldspar separates from five felsic intrusive samples in the Georgetown terrain show a wide range of Pb isotope ratios. The lowest 206 Pb/ 204 Pb analyses are considered to approximate to the Proterozoic initial ratio and indicate a model age of ∼1510 Ma based on the CSIRO-AGSO model. This age is 45 Ma younger than the crystallisation age of the granite, but must be considered a minimum as the initial 206 Pb/ 204 Pb ratio may well prove to be lower after more comprehensive analysis. Sulfide mineralisation within the Einasleigh Metamorphics has a wide range of 206 Pb/ 204 Pb ratios that lie between this granite value and the relatively homogeneous population from Railway Flat. The Railway Flat data are very similar to values for Broken Hill and also the Broken Hill-type Pegmont mineralisation in the Mount Isa Eastern Succession. These data all have significantly lower 207 Pb/ 204 Pb ratios than the CSIRO-AGSO model, suggesting a significantly different source rock environment for this style of mineralisation from that for the sediment hosted deposits

On the numerical treatment of the Griffin-Hill-Eheeler equation

International Nuclear Information System (INIS)

Galleti, D.; Toledo Piza, A.F.R.

The precision attainable in the numerical treatment of the Griffin-Hill-Wheeler equation is studied in a solvable model. Trucation errors related to the generator coordinate kinematics are exhibited and briefly discussed [pt

Aquatic assessment of the Pike Hill Copper Mine Superfund site, Corinth, Vermont

Science.gov (United States)

Piatak, Nadine M.; Argue, Denise M.; Seal, Robert R.; Kiah, Richard G.; Besser, John M.; Coles, James F.; Hammarstrom, Jane M.; Levitan, Denise M.; Deacon, Jeffrey R.; Ingersoll, Christopher G.

2013-01-01

The Pike Hill Copper Mine Superfund site in Corinth, Orange County, Vermont, includes the Eureka, Union, and Smith mines along with areas of downstream aquatic ecosystem impairment. The site was placed on the U.S. Environmental Protection Agency (USEPA) National Priorities List in 2004. The mines, which operated from about 1847 to 1919, contain underground workings, foundations from historical structures, several waste-rock piles, and some flotation tailings. The mine site is drained to the northeast by Pike Hill Brook, which includes several wetland areas, and to the southeast by an unnamed tributary that flows to the south and enters Cookville Brook. Both brooks eventually drain into the Waits River, which flows into the Connecticut River. The aquatic ecosystem at the site was assessed using a variety of approaches that investigated surface-water quality, sediment quality, and various ecological indicators of stream-ecosystem health. The degradation of surface-water quality is caused by elevated concentrations of copper, and to a lesser extent cadmium, with localized effects caused by aluminum, iron, and zinc. Copper concentrations in surface waters reached or exceeded the USEPA national recommended chronic water-quality criteria for the protection of aquatic life in all of the Pike Hill Brook sampling locations except for the location farthest downstream, in half of the locations sampled in the tributary to Cookville Brook, and in about half of the locations in one wetland area located in Pike Hill Brook. Most of these same locations also contained concentrations of cadmium that exceeded the chronic water-quality criteria. In contrast, surface waters at background sampling locations were below these criteria for copper and cadmium. Comparison of hardness-based and Biotic Ligand Model (BLM)-based criteria for copper yields similar results with respect to the extent or number of stations impaired for surface waters in the affected area. However, the BLM

Solar heating and hot water system installed at Cherry Hill, New Jersey. [Hotels

Energy Technology Data Exchange (ETDEWEB)

1979-05-16

The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system went into operation November 8, 1978 and is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are General Electric Company liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

The effects of the introduction of the no-smoking policy at HMYOI Warren Hill on bullying behaviour.

Science.gov (United States)

Lawrence, Sally; Welfare, Heather

2008-01-01

The current research explores the prevalence of bullying behaviour at HMYOI Warren Hill and the Carlford Unit. The introduction of the no-smoking policy at the establishment was also explored in relation to its effect on bullying behaviour given that tobacco has historically been the main item that young people have been bullied for. The Direct and Indirect Prisoner behaviour Checklist--Revised (DIPC-R) and a questionnaire designed to identify the effect of the introduction of the no-smoking policy on bullying behaviour were used within this study to answer the following questions: what is the prevalence of bullying behaviour at Warren Hill and the Carlford Unit, and do young people at Warren Hill and the Carlford Unit think that the rate and nature of bullying has been affected by the introduction of the no-smoking policy? One hundred and fifteen young people took part in the study. At Warren Hill, Bully/Victims were the most prevalent type identified and this was significantly greater than the number of young people identified as Pure Victims or Not Involved. On the Carlford Unit, Not Involved was the most prevalent type identified, and this finding provides limited support for the theories of bullying behaviour identified within the present study. The study found that the rate of bullying decreased following the introduction of the no-smoking policy at Warren Hill. The findings from this study are being used in the development of a new Violence Reduction Policy at HMYOI Warren Hill.

Geophysical tomography for imaging water movement in welded tuff

International Nuclear Information System (INIS)

Daily, W.; Ramirez, A.

1986-01-01

Alterant tomography has been evaluated for its ability to delineate in-situ water flow paths in a fractured welded-tuff rock mass. The evaluation involved a field experiment in which tomographs of electromagnetic attenuation factor (or attenuation rate) at 300 MHZ were made before, during, and after the introduction to the rock of two different water-based tracers: a plain water and dye solution, and salt water and dye. Alterant tomographs were constructed by subtracting, cell by cell, the attenuation factors derived from measurements before each tracer was added to the rock mass from the attenuation factors derived after each tracer was added. The alterant tomographs were compared with other evidence of water movement in the rock: borescope logs of fractures, and postexperiment cores used to locate the dye tracer on the fractured surfaces. These comparisons indicate that alterant tomography is suitable for mapping water flow through fractures and that it may be useful in inferring which of the fractures are hydrologically connected in the image plane. The technique appears to be sensitive enough to delineate flow through a single fracture and to define fractures with a spatial resolution of about 10 cm on an imaging scale of a few meters. 9 refs., 3 figs

Susceptibility of Shallow Landslide in Fraser Hill Catchment, Pahang Malaysia

Directory of Open Access Journals (Sweden)

Wan Nor Azmin Sulaiman

2010-01-01

Full Text Available In tropical areas especially during monsoon seasons intense precipitation is the main caused that trigger the natural shallow landslide phenomena. This phenomenon can be disastrous and widespread in occurrence even in undisturbed forested catchment. In this paper, an attempt has been made to evaluate the susceptibility of natural hill slopes to failure for a popular hill resort area, the Fraser Hill Catchment under different rainfall regimes and soil thickness. A Digital Elevation Model (DEM was prepared for the 8.2 km2 catchment. A GIS based deterministic model was then applied to predict the spatial landslide occurrence within catchment. Model input parameters include bulk density, friction angle, cohesion and hydraulic conductivity were gathered through in situ and lab analysis as well as from previous soil analysis records. Landslides locations were recorded using GPS as well as previous air photos and satellite imagery to establish landslide source areas inventory. The landslide susceptibility map was produced under different precipitation event’s simulation to see the effects of precipitation to stability of the hill slopes of the catchment. The results were categorized into naturally unstable (Defended, Upper Threshold, Lower Threshold, marginal instability (Quasi Stable and stable area (Moderately Stable and Stable. Results of the simulation indicated notable change in precipitation effect on Defended area is between 10mm to 40mm range in a single storm event. However, when storm event is exceeded 120mm, the result on Defended area produced by the model tends to be constant further on. For area categorized as naturally unstable (Factor of Safety, SF<1, with 110 mm of precipitation in a single storm event and soil depth at 2 meters and 4 meters could affect 69.51% and 69.88% respectively of the catchment area fall under that class. In addition, the model was able to detect 4% more of the landslide inventory under shallower soil depth of

Paul Hill d/b/a Alternative Energy Windows and Siding

Science.gov (United States)

Paul Hill d/b/a Alternative Energy Windows and Siding (the Company) is located in Concord, New Hampshire. The settlement involves renovation activities conducted at property constructed prior to 1978, located in Concord, New Hampshire.

Stratigraphy, sedimentology and eruptive mechanisms in the tuff cone of El Golfo (Lanzarote, Canary Islands)

Science.gov (United States)

Pedrazzi, Dario; Martí, Joan; Geyer, Adelina

2013-07-01

The tuff cone of El Golfo on the western coast of Lanzarote (Canary Islands) is a typical hydrovolcanic edifice. Along with other edifices of the same age, it was constructed along a fracture oriented NEE-SWW that coincides with the main structural trend of recent volcanism in this part of the island. We conducted a detailed stratigraphic study of the succession of deposits present in this tuff cone and here interpret them in light of the depositional processes and eruptive dynamics that we were able to infer. The eruptive sequence is represented by a succession of pyroclastic deposits, most of which were emplaced by flow, plus a number of air-fall deposits and ballistic blocks and bombs. We distinguished five different eruptive/depositional stages on the basis of differences in inferred current flow regimes and fragmentation efficiencies represented by the resulting deposits; the different stages may be related to variations in the explosive energy. Eight lithofacies were identified based on sedimentary discontinuities, grain size, components, variations in primary laminations and bedforms. The volcanic edifice was constructed very rapidly around the vent, and this is inferred to have controlled the amount of water that was able to enter the eruption conduit. The sedimentological characteristics of the deposits and the nature and distribution of palagonitic alteration suggest that most of the pyroclastic succession in El Golfo was deposited in a subaerial environment. This type of hydrovolcanic explosive activity is common in the coastal zones of Lanzarote and the other Canary Islands and is one of the main potential hazards that could threaten the human population of this archipelago. Detailed studies of these hydrovolcanic eruptions such as the one we present here can help volcanologists understand the hazards that this type of eruption can generate and provide essential information for undertaking risk assessment in similar volcanic environments.

Food security and ecological footprint of chittagong hill tracts in bangladesh

International Nuclear Information System (INIS)

Bala, B.K.; Hossain, M.A.

2014-01-01

This paper presents food security and ecological footprint of the Chittagong Hill Tracts (CHT) in Bangladesh. To estimate food security and ecological footprint, primary and secondary data were collected and a multistage sampling was designed for selecting the farm households from the three districts of the Hill Tracts of Chittagong. A quantitative method for computation of food security was used. To estimate the environmental sustainability sustainability as upazila (sub-district) levels, a method of computation of ecological footprint developed by Wackernagel was used. Multiple logistic regression models were fitted to data on food security of the farmers in CHT to identify the factors affecting food security at household levels in CHT. Overall status of food security at upazila levels was found to be good for all the upazilas except Rangamati sadar and the best was found Alikadam. Environmental status in the Hill Tracts of Chittagong was poor for all the upazilas. Household food security was found to be significantly (p<0.05) affected by farm size, education, professions, crops cultivated (jhum and tobacco), distance from market and transition from jhum to horticulture. This study supports transition from jhum to horticulture crops for increased food security and banning tobacco cultivation to avoid deforestation in CHT. (author)

USGS Hill Shade Base Map Service from The National Map

Data.gov (United States)

U.S. Geological Survey, Department of the Interior — USGS Hill Shade (or Shaded Relief) is a tile cache base map created from the National Elevation Dataset (NED), a seamless dataset of best available raster elevation...

NPP Grassland: Beacon Hill, U.K., 1972-1993, R1

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains two ASCII text files, one providing productivity measurements for a chalk grassland on Beacon Hill, West Sussex, U.K. (50.92 N, -0.85 W) and...

Stratigraphic relations and hydrologic properties of the Paintbrush Tuff (PTn) hydrologic unit, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Moyer, T.C.; Geslin, J.K.; Flint, L.E.

1996-01-01

Yucca Mountain is being investigated as a potential site for a high- level nuclear waste repository. The intent of this study was to clarify stratigraphic relations within the Paintbrush Tuff (PTn) unit at Yucca Mountain in order to better understand vertical and lateral variations in hydrologic properties as they relate to the lithologic character of these rocks. This report defines informal stratigraphic units within the PTn interval, demonstrates their lateral continuity in the Yucca Mountain region, describes later and vertical variations within them, and characterizes their hydrologic properties and importance to numerical flow and transport models. We present tables summarizing the depth to stratigraphic contacts in cored borehole studies, and unit descriptions and correlations in 10 measured sections

Stratigraphic relations and hydrologic properties of the Paintbrush Tuff (PTn) hydrologic unit, Yucca Mountain, Nevada

Energy Technology Data Exchange (ETDEWEB)

Moyer, T.C.; Geslin, J.K. [Science Applications International Corp., Golden, CO (United States); Flint, L.E. [U.S. Geological Survey, Yucca Mountain Project, Mercury, NV (United States)

1996-08-01

Yucca Mountain is being investigated as a potential site for a high- level nuclear waste repository. The intent of this study was to clarify stratigraphic relations within the Paintbrush Tuff (PTn) unit at Yucca Mountain in order to better understand vertical and lateral variations in hydrologic properties as they relate to the lithologic character of these rocks. This report defines informal stratigraphic units within the PTn interval, demonstrates their lateral continuity in the Yucca Mountain region, describes later and vertical variations within them, and characterizes their hydrologic properties and importance to numerical flow and transport models. We present tables summarizing the depth to stratigraphic contacts in cored borehole studies, and unit descriptions and correlations in 10 measured sections.

Magnetic properties in an ash flow tuff with continuous grain size variation: a natural reference for magnetic particle granulometry

Science.gov (United States)

Till, J.L.; Jackson, M.J.; Rosenbaum, J.G.; Solheid, P.

2011-01-01

The Tiva Canyon Tuff contains dispersed nanoscale Fe-Ti-oxide grains with a narrow magnetic grain size distribution, making it an ideal material in which to identify and study grain-size-sensitive magnetic behavior in rocks. A detailed magnetic characterization was performed on samples from the basal 5 m of the tuff. The magnetic materials in this basal section consist primarily of (low-impurity) magnetite in the form of elongated submicron grains exsolved from volcanic glass. Magnetic properties studied include bulk magnetic susceptibility, frequency-dependent and temperature-dependent magnetic susceptibility, anhysteretic remanence acquisition, and hysteresis properties. The combined data constitute a distinct magnetic signature at each stratigraphic level in the section corresponding to different grain size distributions. The inferred magnetic domain state changes progressively upward from superparamagnetic grains near the base to particles with pseudo-single-domain or metastable single-domain characteristics near the top of the sampled section. Direct observations of magnetic grain size confirm that distinct transitions in room temperature magnetic susceptibility and remanence probably denote the limits of stable single-domain behavior in the section. These results provide a unique example of grain-size-dependent magnetic properties in noninteracting particle assemblages over three decades of grain size, including close approximations of ideal Stoner-Wohlfarth assemblages, and may be considered a useful reference for future rock magnetic studies involving grain-size-sensitive properties.

Ethnoveterinary medicine of the Shervaroy Hills of Eastern Ghats, India as alternative medicine for animals.

Science.gov (United States)

Usha, Swaminathan; Rajasekaran, Chandrasekaran; Siva, Ramamoorthy

2016-01-01

The Eastern Ghats of India is well known for its wealth of natural vegetation and Shervaroy is a major hill range of the Eastern Ghats of Tamil Nadu. Ethnomedicinal studies in the Eastern Ghats of Tamil Nadu or the Shervaroy Hills have been carried out by various researchers. However, there is not much information available on ethnoveterinary medicine in the Eastern Ghats of India. The aim of this study was to examine the potential use of folk plants as alternative medicine for cattle to cure various diseases in the Shervaroy Hills of the Eastern Ghats. Based on interactions with traditional medicine practitioners, it has been observed that a total of 21 medicinal plants belonging to 16 families are used to cure various diseases such as mastitis, enteritis, arthritis, stomatitis, salivation from the mouth, wounding, and conjunctivitis in animals. It has been observed that the traditional knowledge of ethnoveterinary medicine is now confined only among the surviving older people and a few practitioners in the tribal communities of the Shervaroy Hills. Unfortunately, no serious attempts have been made to document and preserve this immense treasure of traditional knowledge.

Investigation of bacterial transport in the large-block test, a thermally perturbed block of Topopah Spring tuff

Energy Technology Data Exchange (ETDEWEB)

Chen, C.I.; Meike, A.; Chuu, Y.J.; Sawvel, A.; Lin, W.

1999-07-01

Transport of bacteria is investigated as part of the Large-Block Test (LBT), a thermally perturbed block of Topopah Spring tuff. Two bacterial species, Bacillus subtilis and Arthrobacter oxydans, were isolated from the Yucca Mountain Tuff. Natural mutants that can grow under the simultaneous presence of the two antibiotics, streptomycin and rifampicin, were selected from these species by laboratory procedures, cultured, and injected into the five heater boreholes of the large block hours before heating was initiated. The temperature, as measured 5 cm above one of the heater boreholes, rose slowly over a matter of months to a maximum of 142 C and to 60 C at the top and bottom of the block. Samples were collected from boreholes located approximately 5 ft below the injection points. Double-drug-resistant microbes also appeared in the heater boreholes where the temperature had been sustainably high throughout the test. The number of double-drug-resistant bacteria that were identified in the collection boreholes increased with time until the heater was deactivated. Negative indications in the collection holes after the heater was deactivated support the supposition that these bacteria were the species that were injected. An apparent homogeneous distribution among the collection boreholes suggests no pattern to the migration of bacteria through the block. The relationship between bacterial migration and the movement of water is not yet understood. These observations indicate the possibility of rapid bacterial transport in a thermally perturbed geologic setting. The implications for colloid transport need to be reviewed.

Investigation of bacterial transport in the large-block test, a thermally perturbed block of Topopah Spring tuff

International Nuclear Information System (INIS)

Chen, C.I.; Meike, A.; Chuu, Y.J.; Sawvel, A.; Lin, W.

1999-01-01

Transport of bacteria is investigated as part of the Large-Block Test (LBT), a thermally perturbed block of Topopah Spring tuff. Two bacterial species, Bacillus subtilis and Arthrobacter oxydans, were isolated from the Yucca Mountain Tuff. Natural mutants that can grow under the simultaneous presence of the two antibiotics, streptomycin and rifampicin, were selected from these species by laboratory procedures, cultured, and injected into the five heater boreholes of the large block hours before heating was initiated. The temperature, as measured 5 cm above one of the heater boreholes, rose slowly over a matter of months to a maximum of 142 C and to 60 C at the top and bottom of the block. Samples were collected from boreholes located approximately 5 ft below the injection points. Double-drug-resistant microbes also appeared in the heater boreholes where the temperature had been sustainably high throughout the test. The number of double-drug-resistant bacteria that were identified in the collection boreholes increased with time until the heater was deactivated. Negative indications in the collection holes after the heater was deactivated support the supposition that these bacteria were the species that were injected. An apparent homogeneous distribution among the collection boreholes suggests no pattern to the migration of bacteria through the block. The relationship between bacterial migration and the movement of water is not yet understood. These observations indicate the possibility of rapid bacterial transport in a thermally perturbed geologic setting. The implications for colloid transport need to be reviewed

77 FR 47625 - Laurel Hill Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Science.gov (United States)

2012-08-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2313-000] Laurel Hill Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request For... Laurel Hill Wind Energy, LLC's application for market-based rate authority, with an accompanying rate...

Amphibian diversity in Shimba Hills National Reserve, Kenya: A ...

African Journals Online (AJOL)

We present the first annotated amphibian checklist of Shimba Hills National Reserve (SHNR). The list comprises of 30 currently known amphibians (28 anurans and two caecilians), which includes 11 families and 15 genera. In addition, individual records per species, distribution in the reserve and brief remarks about the ...

Concentration of carbonate admixture from opalized tuff into one separate fraction

International Nuclear Information System (INIS)

Bogoevski, Slobodan; Boshkovski, Boshko

2016-01-01

White opalized tuff (from the Strmosh locality, Probishtip), as a raw silicate amorphous material, contains some quantity of admixtures. The total quantity of admixtures amounts is about 8% mass. Mine powdery ingredients are homogeneously distributed into the basic silicate mass.Carbonate material is a significant part of present admixtures, and it is possible to be separated with controlled milling. Milling parameters (type and time of milling) enables to concentrate the present CaCO 3 in granulometric fraction<0.032 μm, after 30 min. milling. Reliable evidence about afore mentioned separation is shown with simultaneous view of the results of silicate chemical analysis, DT/TG analysis (750 - 850 °C), and sieve-analysis.From the X-ray analysis it is evident that the present carbonate material exists in crypto crystal to amorphous state. The space where CaCO 3 is hidden, presents the place between basic silicate particles inside the groups, generally with dimensions about 40 to 60 μm. The concentration of CaCO 3 appears when this particle group goes to the process of disintegration. (author)

Uncertainties in sealing a nuclear waste repository in partially saturated tuff

International Nuclear Information System (INIS)

Tillerson, J.R.; Fernandez, J.A.; Hinkebein, T.E.

1989-01-01

Sealing a nuclear waste repository in partially saturated tuff presents unique challenges to assuring performance of sealing components. Design and performance of components for sealing shafts, ramps, drifts, and exploratory boreholes depend on specific features of both the repository design and the site; of particular importance is the hydrologic environment in the unsaturated zone, including the role of fracture flow. Repository design features important to sealing of a repository include the size and location of shaft and ramp accesses, excavation methods, and the underground layout features such as grade (drainage direction) and location relative to geologic structure. Uncertainties about seal components relate to the postclosure environment for the seals, the emplacement methods, the material properties, and the potential performance of the components. An approach has been developed to reduce uncertainties and to increase confidence in seal performance; it includes gathering extensive site characterization data, establishing conservative design requirements, testing seal components in laboratory and field environments, and refining designs of both the seals and the repository before seals are installed. 9 refs., 5 figs., 2 tabs

Experimental Analysis and Process Modeling of Carbon Dioxide Removal Using Tuff

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Emanuele Bonamente

2016-12-01

Full Text Available Removal of carbon dioxide via selective adsorption is a key process to obtain consumer-grade natural gas from biogas and, more generally, CO2 capture and sequestration from gaseous mixtures. The aim of this work is the characterization and classification of a natural alternative to synthetic zeolites that could be used as a carbon dioxide adsorbent. Tuff particulate, easily available as a byproduct of the construction industry, was tested with different laboratory procedures to verify its suitability for CO2 removal applications. Relevant physical and adsorption properties were measured during an intensive experimental campaign. Porosity, pore size distribution, and specific surface area were obtained with mercury intrusion porosimetry. Adsorption isotherms and saturation curves were obtained using two custom experimental apparatuses. The selective adsorption was finally modeled using an original phenomenological parameterization, and a simplified simulation of the process was performed using a computational fluid dynamic approach, validated against observed data. Results show that natural zeolites represent a very promising and sustainable alternative to synthetic zeolites in pressure swing adsorption processes for CO2 removal.

Parametric study of the effects of thermal environment on a waste package for a tuff repository

Energy Technology Data Exchange (ETDEWEB)

Johnstone, J K; Sundberg, W D; Krumhansl, J L [Sandia National Laboratories Albuquerque, NM, (USA)

1982-12-31

The thermal environment has been modeled in a simple reference waste package in a tuff repository for a variety of variables. The waste package was composed of the waste form, canister, overpack and backfill. The emplacement hole was 122cm dia. Waste forms used in the calculations were commercial high level waste (CHLW) and spent fuel (SF). Canister loadings varied from 50 to 100 kW/acre. Primary attention was focused on the backfill behavior in the thermal and chemical environment. Results are related to the maximum temperature calculated for the backfill. These calculations raise serious concerns about the effectiveness of the backfill within the context of the total waste package.

Geotechnical instrumentation requirements for at-depth testing and repository monitoring in tuff

International Nuclear Information System (INIS)

Zimmerman, R.M.

1982-01-01

Minimum required geotechnical measurements for confirmation of repository performance include thermal and thermomechanical responses; changes in stress, strain, and displacements; and pore pressure and groundwater flow characteristics. Conditions expected in tuff are: maximum rock temperatures of less than 250 0 C, stresses less than 100 MPa, strains between +-0.01 mm/mm, and pore pressures less than 35 KPa in the unsaturated zone where hydraulic head is not the primary contributor. The paper describes instrumentation needed to make the desired measurements. In general, the instrumentation and data system are required to be stable and reliable for tens of years. Designs must consider requirements for temperature stability, temperature expansion compensation, moisture resistance, and long-term durability in mining-type environments. Severe requirements such as these suggest consideration of techniques for in-situ replacement of instrumentation. State-of-the-art instrumentation is briefly described along with a discussion of needs for refinement, replacement/recalibration and instrumentation development

Climate Proxy Signals in the Plio-Pleistocene Chemeron and Miocene Lukeino Formations, Baringo Basin, Kenya

Science.gov (United States)

Deino, A. L.; Kingston, J.; Hill, A.; Wilson, K. E.; Edgar, R.; Goble, E.

2009-12-01

The Chemeron Formation is a hominin-bearing, highly fossiliferous sequence of dominantly alluvial fan and fluvial sedimentary rocks, with climatically significant lacustrine intercalations, exposed within the Tugen Hills of the central Kenya Rift. As we have previously documented (Deino et al., 2006; Kingston et al., 2007), the formation contains a sequence of five 3-7 m thick diatomites in the interval 2.7-2.5 Ma that record, at precessional intervals, the repeated occurrence of deep-lake conditions in the Baringo Basin. These lakes appear abruptly, persist for only about 8,000 years of the ~23,000 year precessional cycle, and recede quickly. The oscillations have been tied to marine core and Mediterranean sapropel sections based on high-precision 40Ar/39Ar dating of K-feldspar in tuffs interspersed through the sequence, and paleomagnetic reversal stratigraphy. Ongoing paleontological investigations in the Tugen Hills are addressing the dynamics of high-resolution faunal and ecological change directly related to the fluctuating climatic background, including its effect on hominin evolution. This specific interval in the Baringo Basin/Tugen Hills has been identified by the Hominid Sites and Paleolakes Drilling Project Steering Committee as one of five target areas in East Africa for high-resolution coring studies. The drilling project is currently moving forward to the funding agency proposal development phase. Further exploration in the Tugen Hills has revealed a similar, older sequence of rhythmic alternating diatomites and non-lacustrine sediments in nearby drainages. These beds may represent a precessionally driven climate response possibly associated with the next older orbital eccentricity maximum from ~3.2-2.9 Ma. Characterization of the lithostratigraphy of this area is in progress, and samples of intercalated tuff beds suitable for high-precision single-crystal 40Ar/39Ar dating have been acquired. We have also extended our search for climate proxy records

Crystal chemistry of pyrochlore from the Mesozoic Panda Hill carbonatite deposit, western Tanzania

Science.gov (United States)

Boniface, Nelson

2017-02-01

The Mesozoic Panda Hill carbonatite deposit in western Tanzania hosts pyrochlore, an ore and source of niobium. This study was conducted to establish the contents of radioactive elements (uranium and thorium) in pyrochlore along with the concentration of niobium in the ore. The pyrochlore is mainly hosted in sövite and is structurally controlled by NW-SE (SW dipping) or NE-SW (NW dipping) magmatic flow bands with dip angles of between 60° and 90°. Higher concentrations of pyrochlore are associated with magnetite, apatite and/or phlogopite rich flow bands. Electron microprobe analyses on single crystals of pyrochlore yield very low UO2 concentrations that range between 0 and 0.09 wt% (equivalent to 0 atoms per formula unit: a.p.f.u.) and ThO2 between 0.55 and 1.05 wt% (equivalent to 0.1 a.p.f.u.). The analyses reveal high concentrations of Nb2O5 (ranging between 57.13 and 65.50 wt%, equivalent to a.p.f.u. ranging between 1.33 and 1.43) and therefore the Panda Hill Nb-oxide is classified as pyrochlore sensu stricto. These data point to a non radioactive pyrochlore and a deposit rich in Nb at Panda Hill. The Panda Hill pyrochlore has low concentrations of REEs as displayed by La2O3 that range between 0.10 and 0.49 wt% (equivalent to a.p.f.u. ranging between 0 and 0.01) and Ce2O3 ranging between 0.86 and 1.80 wt% (equivalent to a.p.f.u. ranging between 0.02 and 0.03), Pr2O3 concentrations range between 0 and 0.23 wt% (equivalent to 0 a.p.f.u.), and Y2O3 is 0 wt% (equivalent to 0 a.p.f.u.). The abundance of the REEs in pyroclore at the Panda Hill Carbonatite deposit is of no economic significance.

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada

Science.gov (United States)

du Bray, Edward A.; John, David A.; Box, Stephen E.; Vikre, Peter G.; Fleck, Robert J.; Cousens, Brian L.

2013-04-23

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada // // This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic field but also include 3.9–0.1 Ma rocks of the bimodal, post-subduction Aurora volcanic field. Limited petrographic results for local basement rocks, including Mesozoic granitoid rocks and their metamorphic host rocks, are also included in the compilation. The petrographic data include visual estimates of phenocryst abundances as well as other diagnostic petrographic criteria. The geochemical data include whole-rock major oxide and trace element data, as well as limited whole-rock isotopic data.

Stratigraphy, palaeoenvironments and palaeoecology of the Loch Humphrey Burn lagerstätte and other Mississippian palaeobotanical localities of the Kilpatrick Hills, southwest Scotland

Directory of Open Access Journals (Sweden)

Richard M. Bateman

2016-02-01

Full Text Available Background and Aims. The largely Mississippian strata of the Kilpatrick Hills, located at the western end of the Scottish Midland Valley, enclose several macrofossil floras that together contain ca 21 organ-species of permineralised plants and ca 44 organ-species of compressed plants, here estimated to represent 25 whole-plant species (Glenarbuck = nine, Loch Humphrey Burn Lower = 11, Upper = seven. The most significant locality is the internationally important volcanigenic sequence that is reputedly intercalated within the Clyde Plateau Lava Formation at Loch Humphrey Burn, where ca 30 m of reworked tuffs and other clastic sediments enclose one of the world’s most important terrestrial lagerstätten of this period. We here explore the palaeoecology and palaeoenvironments of the locality, and elucidate its controversial age. Methods. Repeated re-excavation of key exposures allowed recognition of five main depositional units, differing in thickness from 4 m to 12 m. It also permitted detailed sampling for plant macrofossils and microfossils throughout the succession. Several approaches are integrated to re-assess the taphonomy and preservation of these exceptional plant fossils. Key Results. The deposits are rich in taxonomically diverse miospores and in toto contain at least six well-developed compression floras, together with two beds yielding nodules that enclose well-researched anatomically preserved plants permineralised in calcite. Bulk geochemistry shows that the upper nodules formed by migration of Ca with subordinate Mn and Na. Some phylogenetically important plant fossils recovered in the early 20th century have been traced to their source horizons. Trends in relative proportions of macrofossil and microfossil taxa through the sequence are only moderately congruent, perhaps reflecting the likelihood that microfossils sample the regional rather than the local flora. Conclusions. The Loch Humphrey Burn sequence encompasses a wide range

Stratigraphy, palaeoenvironments and palaeoecology of the Loch Humphrey Burn lagerstätte and other Mississippian palaeobotanical localities of the Kilpatrick Hills, southwest Scotland.

Science.gov (United States)

Bateman, Richard M; Stevens, Liadan G; Hilton, Jason

2016-01-01

Background and Aims. The largely Mississippian strata of the Kilpatrick Hills, located at the western end of the Scottish Midland Valley, enclose several macrofossil floras that together contain ca 21 organ-species of permineralised plants and ca 44 organ-species of compressed plants, here estimated to represent 25 whole-plant species (Glenarbuck = nine, Loch Humphrey Burn Lower = 11, Upper = seven). The most significant locality is the internationally important volcanigenic sequence that is reputedly intercalated within the Clyde Plateau Lava Formation at Loch Humphrey Burn, where ca 30 m of reworked tuffs and other clastic sediments enclose one of the world's most important terrestrial lagerstätten of this period. We here explore the palaeoecology and palaeoenvironments of the locality, and elucidate its controversial age. Methods. Repeated re-excavation of key exposures allowed recognition of five main depositional units, differing in thickness from 4 m to 12 m. It also permitted detailed sampling for plant macrofossils and microfossils throughout the succession. Several approaches are integrated to re-assess the taphonomy and preservation of these exceptional plant fossils. Key Results. The deposits are rich in taxonomically diverse miospores and in toto contain at least six well-developed compression floras, together with two beds yielding nodules that enclose well-researched anatomically preserved plants permineralised in calcite. Bulk geochemistry shows that the upper nodules formed by migration of Ca with subordinate Mn and Na. Some phylogenetically important plant fossils recovered in the early 20th century have been traced to their source horizons. Trends in relative proportions of macrofossil and microfossil taxa through the sequence are only moderately congruent, perhaps reflecting the likelihood that microfossils sample the regional rather than the local flora. Conclusions. The Loch Humphrey Burn sequence encompasses a wide range of depositional

Conservation assessment for the autumn willow in the Black Hills National Forest, South Dakota and Wyoming

Science.gov (United States)

J. Hope Hornbeck; Carolyn Hull Sieg; Deanna J. Reyher

2003-01-01

Autumn willow, Salix serissima (Bailey) Fern., is an obligate wetland shrub that occurs in fens and bogs in the northeastern United States and eastern Canada. Disjunct populations of autumn willow occur in the Black Hills of South Dakota. Only two populations occur on Black Hills National Forest lands: a large population at McIntosh Fen and a small...

78 FR 76100 - Black Hills National Forest Advisory Board

Science.gov (United States)

2013-12-16

...: The Black Hills National Forest Advisory Board (Board) will meet in Rapid City, South Dakota. The... Ranger District, 8221 South Highway 16, Rapid City, South Dakota. Written comments may be submitted as... the public. The agenda will include time for people to make oral statements of three minutes or less...

Multiple-scale roost habitat comparisons of female Merriam's wild turkeys in the southern Black Hills, South Dakota

Science.gov (United States)

Daniel J. Thompson; Mark A. Rumble; Lester D. Flake; Chad P. Lehman

2009-01-01

Because quantity and quality of roosting habitat can affect Merriam's Wild Turkey (Meleagris gallopavo merriami) distribution, we described habitat characteristics of Merriam's turkey roost sites in the southern Black Hills of South Dakota. Varying proportions of Merriam's turkeys in the southern Black Hills depended on supplemental feed from livestock...

Orno-Cotino-Quercetum Pubescentis Ass. nova prov. on the slopes of Titel hill (Serbia

Directory of Open Access Journals (Sweden)

Butorac Branislava

2008-01-01

Full Text Available Studied by many botanists from the floristic and vegetation-geographical aspects over the last hundred years, the herbaceous plant cover in dominant on Titel Hill. The first data on plant communities were registered in 1983, when a significant contribution to the study of vegetation of steppe character was made. At that time, presence of shrubby remnants of forest vegetation on Titel Hill was registered. Since 1983, fragments of typical xerothermic woods of pubescent oak have been registered.

The Generalized Hill Model: A Kinematic Approach Towards Active Muscle Contraction

Science.gov (United States)

Menzel, Andreas; Kuhl, Ellen

2014-01-01

Excitation-contraction coupling is the physiological process of converting an electrical stimulus into a mechanical response. In muscle, the electrical stimulus is an action potential and the mechanical response is active contraction. The classical Hill model characterizes muscle contraction though one contractile element, activated by electrical excitation, and two non-linear springs, one in series and one in parallel. This rheology translates into an additive decomposition of the total stress into a passive and an active part. Here we supplement this additive decomposition of the stress by a multiplicative decomposition of the deformation gradient into a passive and an active part. We generalize the one-dimensional Hill model to the three-dimensional setting and constitutively define the passive stress as a function of the total deformation gradient and the active stress as a function of both the total deformation gradient and its active part. We show that this novel approach combines the features of both the classical stress-based Hill model and the recent active-strain models. While the notion of active stress is rather phenomenological in nature, active strain is micro-structurally motivated, physically measurable, and straightforward to calibrate. We demonstrate that our model is capable of simulating excitation-contraction coupling in cardiac muscle with its characteristic features of wall thickening, apical lift, and ventricular torsion. PMID:25221354

Evaluating Complex Magma Mixing via Polytopic Vector Analysis (PVA in the Papagayo Tuff, Northern Costa Rica: Processes that Form Continental Crust

Directory of Open Access Journals (Sweden)

Guillermo E. Alvarado

2013-08-01

Full Text Available Over the last forty years, research has revealed the importance of magma mixing as a trigger for volcanic eruptions, as well as its role in creating the diversity of magma compositions in arcs. Sensitive isotopic and microchemical techniques can reveal subtle evidence of magma mixing in igneous rocks, but more robust statistical techniques for bulk chemical data can help evaluate complex mixing relationships. Polytopic vector analysis (PVA is a multivariate technique that can be used to evaluate suites of samples that are produced by mixing of two or more magma batches. The Papagayo Tuff of the Miocene-Pleistocene Bagaces Formation in northern Costa Rica is associated with a segment of the Central American Volcanic Arc. While this segment of the arc is located on oceanic plateau, recent (<8 Ma ignimbrites bear the chemical signatures of upper continental crust, marking the transition from oceanic to continental crust. The Papagayo Tuff contains banded pumice fragments consistent with one or more episodes of mixing/mingling to produce a single volcanic deposit. The PVA solution for the sample set is consistent with observations from bulk chemistry, microchemistry and petrographic data from the rocks. However, without PVA, the unequivocal identification of the three end-member solution would not have been possible.

Key tiger habitats in the Garo Hills of Meghalaya

Science.gov (United States)

Ashish Kumar; Bruce G. Marcot

2010-01-01

We describe assumed tiger habitat characteristics and attempt to identify potential tiger habitats in the Garo Hills region of Meghalaya, North East India. Conserving large forest tracts and protected wildlife habitats provides an opportunity for restoring populations of wide-ranging wildlife such as tigers and elephants. Based on limited field observations coupled...

Do Welsh hill farmers dream of radioactive sheep?

International Nuclear Information System (INIS)

Roberts, Gwyn; Williams, Aled; Last, D.

1993-01-01

A low-power portable device is being used successfully in North Wales to provide precise position-logging of sheep grazing on upland hill pastures following irradiation by fallout from the Chernobyl reactor. This follows the discovery that radiation levels appear to vary significantly among sheep from the same flock, suggesting hot-spots of radiation. The design and execution of the system is described. (UK)

Antimicrobial activity of Davilla elliptica St. Hill (Dilleniaceae

Directory of Open Access Journals (Sweden)

D.C. Michelin

Full Text Available Davilla elliptica St. Hill ("lixinha", family Dilleniaceae, is commonly used in the Brazilian folk medicine as purgative and stimulant. This work evaluated the antimicrobial activity of the methanol and chloroform extracts of the leaves and barks of D. elliptica using the disc-diffusion method. The results obtained showed that the methanolic extracts of the leaves and barks presented antimicrobial activity against the tested microorganisms.

Dehydration and rehydration of a tuff vitrophyre

International Nuclear Information System (INIS)

Vaniman, D.; Bish, D., Chipera, S.

1993-01-01

The basal vitrophyre of the Topopah Spring Member of the Paintbrush Tuff at Yucca Mountain, Nevada, is a perlitic glass with 2.8 to 4.6% water. The dehydration of this vitrophyre was studied by thermogravimetric analysis (TGA) and by isothermal heating at 50 degrees, 100 degrees, 200 degrees, and 400 degrees C for 3.4 years followed by 1.1 years of rehydration at high controlled humidity (∼79% relative humidity). No crystallization of the glass was observed in long-term dehydration or rehydration; the only observed chemical alteration was loss of up to 60% of original fluorine. TGA studies show a characteristic two-stage dehydration of the vitrophyre, with two-thirds to three-fourths weight loss occurring most rapidly at temperatures ranging from 278 degrees to 346 degrees C in 10 degrees C/min heating experiments. The remaining water, about 1% in all of the vitrophyre samples studied regardless of total water content, is lost only on second-stage heating to temperatures above 650 degrees C. Long-term isothermal heating at ≤400 degrees C releases only the first-stage water. Loss of essentially all first-stage water occurred in less than 1 hour at 400 degrees C; proportionately lower losses were obtained at 200 degrees and 100 degrees C. Small (0.2%) water loss occurred in the 50 degrees C experiment. A time-temperature-dehydration diagram generated from the isothermal heating data shows a clustering of dehydration contours that are the equilibrium equivalent of the rapid first-stage water loss in dynamic TGA experiments. These dry-heating experiments provide an end-member characterization of glass transformations for comparison with water-saturated heating experiments in which glass alteration is prominent. 29 figs., 7 figs., 7 tabs

Paleotransport of lanthanides and strontium recorded in calcite compositions from tuffs at Yucca Mountain, Nevada, USA

International Nuclear Information System (INIS)

Vaniman, D.T.; Chipera, S.J.

1996-01-01

Secondary calcite occurs in both saturated and unsaturated hydrologic zones (SZ and UZ, respectively) in the tuffs at Yucca Mountain, Nevada, USA. In the upper UZ, the major constituents of the calcite crystal structure (C, O) have surface origins. At greater depth there is a open-quotes barren zone,close quotes straddling the water table, where calcite is rare and mixing of surface and subsurface sources may occur. Deep in the SZ, distinctive Mn calcites reflect deep sources, including Ca released as analcime or albite formed and carbonates derived from underlying Paleozoic rocks. In the UZ and in the barren zone, above the deep Mn calcites, variations in calcite lanthanide chemistry can be used to distinguish rhyolitic from quartz-latitic sources. Lanthanide ratios and Sr contents of calcites record the chemical evolution of waters flowing through the UZ and upper SZ. Variations in calcite chemistry in the UZ and in the barren zone show that (1) Sr, which is readily exchanged with clays or zeolites, is essentially removed from some flowpaths that are in contact with these minerals and (2) traces of Mn oxides found in the tuffs have a significant effect of groundwater chemistry in the UZ and in the barren zone by removing almost all Ce from solution (evidenced by characteristic Ce depletions in calcite throughout this zone). Extreme Ce removal may be a result of Ce oxidation (Ce 3+ → Ce 4+ ) at the surfaces of some Mn oxides, particularly rancieite. Higher Sr contents and lack of Ce depletions in the deeper Mn calcites reflect different ages, origins, and transport systems. The calcite record of lanthanide and Sr transport in the UZ shows that minor minerals (clays and zeolites) and even trace minerals (Mn oxides) will affect the compositions of groundwaters that flow over distances greater than a few tens of meters. 43 refs., 8 figs., 4 tabs

Some noteworthy distributional records from the Gwassi Hills area ...

African Journals Online (AJOL)

A preliminary inventory of birds occurring in the Gwassi Hills area was compiled by Bradley et .... Woodpecker by some), on the basis of a paler grey head and underparts, and the absence of .... Bay, 50 km to the northeast (Lewis & Pomeroy 1989, D. Turner pers. ... These birds appeared slightly darker with more slaty tones.

Geoheritage and geotourism potential of the Strzelin Hills (Sudetic Foreland, SW Poland

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Solarska Anna

2010-01-01

Full Text Available The aim of this paper is to present a state of knowledge about geotourism potential of the Strzelin Hills. Still there is no geotouristic infrastructure in the Strzelin Hills that could make available all their advantages for educational purposes. There are being carried out works on inventory and documentation to create a base for a development of geotourism. The geotouristic potential is described on the basis of previously studied and valorized objects of geological and geomorphological heritage. There were inventoried 38 objects of geoheritage. During valorization of 17 geosites and geomorphosites were selected 8 represented objects, which present 10 from the 15 thematic groups. There were briefly described 6 of them in this paper. .

78 FR 35951 - Proposed Low-Effect Habitat Conservation Plan for the City of Santa Cruz Graham Hill Water...

Science.gov (United States)

2013-06-14

...] Proposed Low-Effect Habitat Conservation Plan for the City of Santa Cruz Graham Hill Water Treatment Plant... grasshopper (Trimerotropis infantilis), and will address associated impacts and conservation measures for the... lawful activities associated with the operation and maintenance of the existing Graham Hill Water...

Rainwater harvesting potential sites at margalla hills national park

International Nuclear Information System (INIS)

Khalid, B.; Mushtaq, N.; Sial, M.

2013-01-01

Life without water is not possible. Adoption of modern lifestyle and increase in population is leading to a water scarce world. The demand of world population cannot be met , which is resulting in increased groundwater abstraction. The world is facing water crisis and Pakistan is no exception. Urban areas of Pakistan are affected badly where extraction is higher while the construction of pavements has disturbed groundwater infiltration. The Federal Capital of Pakistan, Islamabad, is located in Pothohar region of the country and faces severe water shortages, particularly during summers. Extensive drilling by public and private users lowers groundwater table. Satellite imagery of LANDSAT 7 ETM+ and ASTER DEM 30m resolution were used to construct the site suitability map for groundwater recharge of Margalla Hills National Park. Factors considered included land cover, drainage density, elevation and slope. Suitable weight ages were assigned to these factors according to their influence on infiltration in the study area. Groundwater recharge at Margalla Hills National Park will be effective in dealing with water crisis in Islamabad as it will raise groundwater table of the adjacent areas. (author)

New SHRIMP zircon results from Broken Hill: towards robust stratigraphic and event timing

International Nuclear Information System (INIS)

Page, R.W.; Stevens, B.P.J.

1999-01-01

Full text: Zircon U-Pb SHRIMP geochronology is a powerful means of elucidating geological ages, providing that it is integrated with unequivocal field constraints, and providing that the fundamental assumptions which are behind any isotopic dating methods are geologically validated. In an attempt to better quantify the timing of Broken Hill's complex history and to reduce some current uncertainties, we report initial results from a new U-Pb SHRIMP investigation. This program was planned within the background of our own disparate stratigraphic and structural approaches to Broken Hill geology, and with objectives to (a) benchmark our new age results with those of previous workers as well as our own previous work in the Broken Hill Group, (b) evaluate and test the evidence for reported Archaean basement terrain, (c) date stratigraphic units in the upper parts of the Willyama Supergroup, (d) better constrain the timing of deformational events. Our U-Pb SHRIMP work on zircons from layered paragneisses in the Redan Geophysical Zone near Farmcote was catalysed by Nutman and Ehlers' (1998a) preferred interpretation that these 'strondhjemitic' gneisses represent an original ∼2650 Ma protolith. Our work finds zircon provenance age signatures typical of almost all ca. 1700 Ma metasediments, whether in the Broken Hill Block or other Australian Palaeoproterozoic settings. This therefore suggests that the rocks are not Archaean basement, but are part of a Thackaringa Group package possibly deposited about 1705-1710 Ma ago. New SHRIMP work on the Alma Gneiss provides a magmatic age of 1704±3 Ma, and a minimum stratigraphic age for host Thackaringa Group. This result is within error of our ages for other granitoids (1703±3 Ma, 1704±3 Ma) in the same stratigraphic position near Farmcote. As the Thackaringa Group is no more than 1000-1500 metres thick and includes 1710-1700 Ma detrital zircons, pan of the Alma Gneiss intrusion may well have been shallowly intruded, and akin to

Air-injection field tests to determine the effect of a heat cycle on the permeability of welded tuff

International Nuclear Information System (INIS)

Lee, K.H.; Ueng, Tzou-Shin.

1991-01-01

As part of a series of prototype tests conducted in preparation for site characterization of the potential nuclear-waste repository site at Yucca Mountain, Nevada, air-injection tests were conducted in the welded tuffs in G-Tunnel at the Nevada Test Site. The objectives were to characterize the permeability of the highly fractured tuff around a horizontal heater emplacement borehole, and to determine the effect of a heating and cooling cycle on the rock-mass permeability. Air was injected into packed-off intervals along the heater borehole. The bulk permeability of the rock adjacent to the test interval and the aperture of fractures intersecting the interval were computed from the air-flow rate, temperature, and pressure at steady state. The bulk permeability of intervals along with borehole varied from a minimum of 0.08 D to a maximum of over 144 D and the equivalent parallel-plate apertures of fractures intersecting the borehole varied from 70 to 589 μm. Higher permeabilities seemed to correlate spatially with the mapped fractures. The rock was then heated for a period of 6.5 months with an electrical-resistive heater installed in the borehole. After heating, the rock was allowed to cool down to the ambient temperature. The highest borehole wall temperature measured was 242 degree C. Air injection tests were repeated following the heating and cooling cycle, and the results showed significant increases in bulk permeability ranging from 10 to 1830% along the borehole. 8 ref., 6 figs., 3 tabs

Estimates of the hydrologic impact of drilling water on core samples taken from partially saturated densely welded tuff

International Nuclear Information System (INIS)

Buscheck, T.A.; Nitao, J.J.

1987-09-01

The purpose of this work is to determine the extent to which drill water might be expected to be imbibed by core samples taken from densely welded tuff. In a related experimental study conducted in G-Tunnel, drill water imbibition by the core samples was observed to be minimal. Calculations were carried out with the TOUGH code with the intent of corroborating the imbibition observations. Due to the absence of hydrologic data pertaining directly to G-Tunnel welded tuff, it was necessary to apply data from a similar formation. Because the moisture retention curve was not available for imbibition conditions, the drainage curve was applied to the model. The poor agreement between the observed and calculated imbibition data is attributed primarily to the inappropriateness of the drainage curve. Also significant is the value of absolute permeability (k) assumed in the model. Provided that the semi-log plot of the drainage and imbibition moisture retention curves are parallel within the saturation range of interest, a simple relationship exists between the moisture retention curve, k, and porosity (/phi/) which are assumed in the model and their actual values. If k and /phi/ are known, we define the hysteresis factor λ to be the ratio of the imbibition and drainage suction pressures for any saturation within the range of interest. If k and /phi/ are unknown, λ also accounts for the uncertainties in their values. Both the experimental and modeling studies show that drill water imbibition by the core has a minimal effect on its saturation state. 22 refs., 6 figs., 2 tabs

Petrologic and geochemical characterization of the Bullfrog Member of the Crater Flat Tuff: outcrop samples used in waste package experiments

International Nuclear Information System (INIS)

Knauss, K.G.

1983-09-01

In support of the Waste Package Task within the Nevada Nuclear Waste Storage Investigation (NNWSI), experiments on hydrothermal rock/water interaction, corrosion, thermomechanics, and geochemical modeling calculations are being conducted. All of these activities require characterization of the initial bulk composition, mineralogy, and individual phase geochemistry of the potential repository host rock. This report summarizes the characterization done on samples of the Bullfrog Member of the Crater Flat Tuff (Tcfb) used for Waste Package experimental programs. 11 references, 17 figures, 3 tables

Preliminary drift design analyses for nuclear waste repository in tuff

International Nuclear Information System (INIS)

Hardy, M.P.; Brechtel, C.E.; Goodrich, R.R.; Bauer, S.J.

1990-01-01

The Yucca Mountain Project (YMP) is examining the feasibility of siting a repository for high-level nuclear waste at Yucca Mountain, on and adjacent to the Nevada Test Site (NTS). The proposed repository will be excavated in the Topopah Spring Member, which is a moderately fractured, unsaturated, welded tuff. Excavation stability will be required during construction, waste emplacement, retrieval (if required), and closure to ensure worker safety. The subsurface excavations will be subject to stress changes resulting from thermal expansion of the rock mass and seismic events associated with regional tectonic activity and underground nuclear explosions (UNEs). Analyses of drift stability are required to assess the acceptable waste emplacement density, to design the drift shapes and ground support systems, and to establish schedules and cost of construction. This paper outlines the proposed methodology to assess drift stability and then focuses on an example of its application to the YMP repository drifts based on preliminary site data. Because site characterization activities have not begun, the database currently lacks the extensive site-specific field and laboratory data needed to form conclusions as to the final ground support requirements. This drift design methodology will be applied and refined as more site-specific data are generated and as analytical techniques and methodologies are verified during the site characterization process

The Lister Hill National Center for Biomedical Communications.

Science.gov (United States)

Smith, K A

1994-09-01

On August 3, 1968, the Joint Resolution of the Congress established the program and construction of the Lister Hill National Center for Biomedical Communications. The facility dedicated in 1980 contains the latest in computer and communications technologies. The history, program requirements, construction management, and general planning are discussed including technical issues regarding cabling, systems functions, heating, ventilation, and air conditioning system (HVAC), fire suppression, research and development laboratories, among others.

Optimizing hill seeding density for high-yielding hybrid rice in a single rice cropping system in South China.

Directory of Open Access Journals (Sweden)

Danying Wang

Full Text Available Mechanical hill direct seeding of hybrid rice could be the way to solve the problems of high seeding rates and uneven plant establishment now faced in direct seeded rice; however, it is not clear what the optimum hill seeding density should be for high-yielding hybrid rice in the single-season rice production system. Experiments were conducted in 2010 and 2011 to determine the effects of hill seeding density (25 cm×15 cm, 25 cm×17 cm, 25 cm×19 cm, 25 cm×21 cm, and 25 cm×23 cm; three to five seeds per hill on plant growth and grain yield of a hybrid variety, Nei2you6, in two fields with different fertility (soil fertility 1 and 2. In addition, in 2012 and 2013, comparisons among mechanical hill seeding, broadcasting, and transplanting were conducted with three hybrid varieties to evaluate the optimum seeding density. With increases in seeding spacing from 25 cm×15 cm to 25 cm×23 cm, productive tillers per hill increased by 34.2% and 50.0% in soil fertility 1 and 2. Panicles per m2 declined with increases in seeding spacing in soil fertility 1. In soil fertility 2, no difference in panicles per m2 was found at spacing ranging from 25 cm×17 cm to 25 cm×23 cm, while decreases in the area of the top three leaves and aboveground dry weight per shoot at flowering were observed. Grain yield was the maximum at 25 cm×17 cm spacing in both soil fertility fields. Our results suggest that a seeding density of 25 cm×17 cm was suitable for high-yielding hybrid rice. These results were verified through on-farm demonstration experiments, in which mechanical hill-seeded rice at this density had equal or higher grain yield than transplanted rice.

Effects of elevated temperature and pore pressure on the mechanical behavior of Bullfrog tuff

International Nuclear Information System (INIS)

Olsson, W.A.

1982-02-01

Samples of the Bullfrog Member of the Crater Flat Tuff from the depth interval 758.9 to 759.2 m in hole USW-G1 on the Nevada Test Site were tested in triaxial compression. Test conditions were: (1) effective confining pressure to 20 MPa; (2) temperature of 200 0 C; (3) both dry and with pore water pressures from 3.4 to 5 MPa; and (4) a strain-rate of 10 -4 /s. The results suggest that the presence of water causes the strength to decrease. In addition, the brittle-ductile transition pressure for this rock was found to be about 15 MPa, regardless of saturation. Below this pressure deformation is characterized by unstable stress drops and the development of a single fracture, and above this pressure deformation is stable and distributed more uniformly throughout the sample

The effect of temperature on the sorption of technetium, uranium, neptunium and curium on bentonite, tuff and granodiorite

International Nuclear Information System (INIS)

Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Ilett, D.J.; Tweed, C.J.; Yui, M.

1997-01-01

A study of the sorption of the radioelements technetium; uranium; neptunium; and curium onto geological materials has been carried out as part of the PNC program to increase confidence in the performance assessment for a high-level radioactive waste repository in Japan. Batch sorption experiments have been performed in order to study the sorption of the radioelements onto bentonite, tuff and granodiorite from equilibrated de-ionized water under strongly-reducing conditions at both room temperature and at 60 C. Mathematical modelling using the geochemical speciation program HARPHRQ in conjunction with the HATCHES database has been undertaken in order to interpret the experimental results

Generation of terrestrial radiation database in the Larsemann Hills, Antarctica

International Nuclear Information System (INIS)

Pal, Rupali; Dhabekar, Bhushan; Jose, Jis Romal; Chinnaesakki, S.; Bakshi, A.K.; Datta, D.; Pradeepkumar, K.S.

2018-01-01

Natural background radiation in the environment includes terrestrial radiation, cosmic radiation from space and air activity due to radon/thoron. It is known that cosmic contribution increases near the poles. The terrestrial component is largely due to 232 Th and 238 U series and 40 K. BARC under the cosmic ray dosimetry project with National Centre for Antarctic and Ocean Research (NCAOR) has taken up measurement of natural background radiation at Larsemann Hills, Antarctica. The project includes generation of baseline data on terrestrial radioactivity in water, soil and rock and estimation of cosmic ray doses. Extensive radiation surveys were carried out by the BARC team in the 35 th and 36 th expedition in and around Larsemann hills in East Antarctica where the third Indian station 'Bharati' is situated. This paper presents mapping of terrestrial radiation levels in Antarctica which will help in strengthening the background radiation database and develop a Radiation Informatics System (RIS)

Age and paragenesis of mineralisation at Coronation Hill uranium deposit, Northern Territory, Australia

Science.gov (United States)

Orth, Karin; Meffre, Sebastien; Davidson, Garry

2014-06-01

Coronation Hill is a U + Au + platinum group elements deposit in the South Alligator Valley (SAV) field in northern Australia, south of the better known unconformity-style U East Alligator Rivers (EAR) field. The SAV field differs from the EAR by having a more complex basin-basement architecture. A volcanically active fault trough (Jawoyn Sub-basin) developed on older basement and then was disrupted by renewed faulting, before being buried beneath regional McArthur Basin sandstones that are also the main hanging wall to the EAR deposits. Primary mineralisation at Coronation Hill formed at 1607 ± 26 Ma (rather than 600-900 Ma as previously thought), and so it is likely that the SAV was part of a single west McArthur Basin dilational event. Most ore is hosted in sub-vertical faults and breccias in the competent volcanic cover sequence. This favoured fluid mixing, acid buffering (forming illite) and oxidation of Fe2+ and reduced C-rich assemblages as important uranium depositional mechanisms. However, reduction of U in fractured older pyrite (Pb model age of 1833 ± 67 Ma) is an important trap in diorite. Some primary ore was remobilised at 675 ± 21 Ma to form coarse uraninite + Ni-Co pyrite networks containing radiogenic Pb. Coronation Hill is polymetallic, and in this respect resembles the `egress'-style U deposits in the Athabascan Basin (Canada). However, these are all cover-hosted. A hypothesis for further testing is that Coronation Hill is also egress-style, with ores formed by fluids rising through basement-hosted fault networks (U reduction by diorite pyrite and carbonaceous shale), and into veins and breccias in the overlying Jawoyn Sub-basin volcano-sedimentary succession.

Development and Validation of a Tool for Measurement of Patient Satisfaction with Nursing Care at Oak Hill Hospital.

Science.gov (United States)

Callow, Elizabeth K.

The Department of Nursing at Oak Hill Hospital, Spring Hill (Florida) did not have a measurement instrument for patient evaluation of hospital nursing services. An instrument to measure patient satisfaction with nursing was developed and validated. Criteria identified through a literature search were reviewed, modified, and validated by a…

U-Pb (SHRIMP II) Age of zircons from ash tuffs of the upper vendian Chernyi Kamen formation (Sylvitsa group, Middle Urals)

International Nuclear Information System (INIS)

Ronkin, Yu.L.; Grazhdankin, D.V.; Maslov, A.V.; Mizens, G.A.; Matukov, D.I.; Krupenin, M.T.; Petrov, G.A.; Lepikhina, O.P.; Kornilova, A.Yu.

2006-01-01

To make more precise the model of correlation of the Middle Urals western slope upper vendian layers with the White Sea remote layers one carried out the SHRIMP-II procedure base U-Pb-dating of the volcanogenic zircons from the ash tuffs and of the volcanogenic zircon enclosing argillites of the Middle Urals Chernyi Kamen formation. The obtained age value of the studied zircons equal to 557+-13 million years is in line with the geological data [ru

Three-dimensional modeling of flow through fractured tuff at Fran Ridge

International Nuclear Information System (INIS)

Eaton, R.R.; Ho, C.K.; Glass, RJ.; Nicholl, M.J.; Arnold, B.W.

1996-09-01

Numerical studies have been made of an infiltration experiment at Fran Ridge using the TOUGH2 code to aid in the selection of computational models for performance assessment. The exercise investigates the capabilities of TOUGH2 to model transient flows through highly fractured tuff and provides a possible means of calibration. Two distinctly different conceptual models were used in the TOUGH2 code, the dual permeability model and the equivalent continuum model. The infiltration test modeled involved the infiltration of dyed ponded water for 36 minutes. The 205 gallon infiltration of water observed in the experiment was subsequently modeled using measured Fran Ridge fracture frequencies, and a specified fracture aperture of 285 microm. The dual permeability formulation predicted considerable infiltration along the fracture network, which was in agreement with the experimental observations. As expected, al fracture penetration of the infiltrating water was calculated using the equivalent continuum model, thus demonstrating that this model is not appropriate for modeling the highly transient experiment. It is therefore recommended that the dual permeability model be given priority when computing high-flux infiltration for use in performance assessment studies

Three-dimensional modeling of flow through fractured tuff at Fran Ridge

International Nuclear Information System (INIS)

Eaton, R.R.; Ho, C.K.; Glass, R.J.; Nicholl, M.J.; Arnold, B.W.

1996-01-01

Numerical studies have been made of an infiltration experiment at Fran Ridge using the TOUGH2 code to aid in the selection of computational models for performance assessment. The exercise investigates the capabilities of TOUGH2 to model transient flows through highly fractured tuff and provides a possible means of calibration. Two distinctly different conceptual models were used in the TOUGH2 code, the dual permeability model and the equivalent continuum model. The infiltration test modeled involved the infiltration of dyed ponded water for 36 minutes. The 205 gallon filtration of water observed in the experiment was subsequently modeled using measured Fran Ridge fracture frequencies, and a specified fracture aperture of 285 μm. The dual permeability formulation predicted considerable infiltration along the fracture network, which was in agreement with the experimental observations. As expected, minimal fracture penetration of the infiltrating water was calculated using the equivalent continuum model, thus demonstrating that this model is not appropriate for modeling the highly transient experiment. It is therefore recommended that the dual permeability model be given priority when computing high-flux infiltration for use in performance assessment studies

Galileo's 'Jumping-Hill' Experiment in the Classroom--A Constructivist's Analysis.

Science.gov (United States)

Kubli, Fritz

2001-01-01

Uses Galileo's 'jumping-hill' experiment as an historical element to improve science teaching in the classroom. Illustrates that the experiment can stimulate an animated discussion in the classroom, even if precise historic circumstances are not mentioned. The historical dimensions bring some color into the lesson, which increases attention. (SAH)

Around the Bend: The Curious Power of the Hills around Queenstown, Tasmania

Directory of Open Access Journals (Sweden)

Emily Bullock

2012-03-01

Full Text Available This article traces a concern with excess and waste, landscape and identity in a town on the western periphery of Tasmania.  Queenstown’s bald hills have been a popular tourist drawcard since the turn of the century, sold in travel guides and brochures as a spectacular ‘moonscape’. A combination of a severe bushfire in 1896 and the emission of sulphurous gases from the pyritic smelting process at the Mt Lyell Copper Mine have resulted in Queenstown’s weird denuded landscape. But the locals have grown attached to the hills and want to preserve their baldness.  Here, the impulse to preserve a grotesque landscape registers a culture surviving on desecration to stave off its own disappearance.

Prevalence of Dermatoses in Tribal Population of Kalrayan Hill (South Arcot District

Directory of Open Access Journals (Sweden)

C Mahalingam

1986-01-01

Full Text Available A sample survey was conducted to find out the prevalence of dermatoses among the tribal population of Kalrayan hill in South Arcot district who were recently found out .from the hidden spots of the hill. The prevalence of dermatoses was 40% among the 242 screened. Scabies had a prevalence of 22.7% and was more among the tribal s chool children put in huts, emphasizing the need for adequate shelter and health education. The low frequency of nutritional dermatoses 3.7% is attributed to the implementation of the noon-meal scheme. Surprising low prevalence rate for leprosy (1.7% in this highly endemic district of South Arcot needs further probing to find out some clues for protection from leprosy.

Survey of geophysical techniques for site characterization in basalt, salt and tuff

International Nuclear Information System (INIS)

Jones, G.M.; Blackey, M.E.; Rice, J.E.; Murphy, V.J.; Levine, E.N.; Fisk, P.S.; Bromery, R.W.

1987-07-01

Geophysical techniques may help determine the nature and extent of faulting in the target areas, along with structural information that would be relevant to questions concerning the future integrity of a high-level-waste repository. Chapters focus on particular geophysical applications to four rock types - basalt, bedded salt, domal salt and tuff - characteristic of the sites originally proposed for site characterization. No one geophysical method can adequately characterize the geological structure beneath any site. The seismic reflection method, which is generally considered to be the most incisive of the geophysical techniques, has to date provided only marginal information on structure at the depth of the proposed repository at the Hanford, Washington, site, and no useful results at all at the Yucca Mountain, Nevada, site. This result is partially due to geological complexity beneath these sites, but may also be partially attributed to the use of inappropriate acquisition and processing parameters. To adequately characterize a site using geophysics, modifications will have to be made to standard techniques to emphasize structural details at the depths of interest. 137 refs., 43 figs., 4 tabs

Mosquito diversity in Keeriparai and Mundanthurai hill ranges of the Western Ghats, southern India

Directory of Open Access Journals (Sweden)

A. Munirathinam

2015-07-01

Full Text Available After a gap of 25 years the Centre for Research in Medical Entomology (CRME surveyed the mosquito biodiversity in the tail-end hill ranges of the Western Ghats, viz., Kanyakumari (Keeriparai and Tirunelveli districts (Kalakkad-Mundanthurai Tiger Reserve (KMTR and Courtallam of Tamil Nadu between July 2010 and June 2013.  The altitude of the hills ranged from 100–950 m covered by evergreen forests.  A major emphasis was given to collect the immature stages of mosquitoes, from various breeding habitats, viz., slow flowing streams, spring pool, rocky pool, leaf axils, latex cup, tree hole, bamboo stumps, etc.  Altogether 4602 immature individuals were collected, reared individually to be identified at the adult stage.  A total of 3583 specimens belonging to 50 species classified under 21 genera and 18 subgenera were recorded.  The major vector species found in these hill ranges were Stegomyia aegypti, S. albopicta (Dengue and Chikungunya, Culex bitaeniorhynchus, C. tritaeniorhynchus (Japanese encephalitis, Downsiomyia nivea (diurnally subperiodic filariasis and Anopheles mirans (Simian malaria vectors were recorded. 

The Goodwin model: behind the Hill function.

Directory of Open Access Journals (Sweden)

Didier Gonze

Full Text Available The Goodwin model is a 3-variable model demonstrating the emergence of oscillations in a delayed negative feedback-based system at the molecular level. This prototypical model and its variants have been commonly used to model circadian and other genetic oscillators in biology. The only source of non-linearity in this model is a Hill function, characterizing the repression process. It was mathematically shown that to obtain limit-cycle oscillations, the Hill coefficient must be larger than 8, a value often considered unrealistic. It is indeed difficult to explain such a high coefficient with simple cooperative dynamics. We present here molecular models of the standard Goodwin model, based on single or multisite phosphorylation/dephosphorylation processes of a transcription factor, which have been previously shown to generate switch-like responses. We show that when the phosphorylation/dephosphorylation processes are fast enough, the limit-cycle obtained with a multisite phosphorylation-based mechanism is in very good quantitative agreement with the oscillations observed in the Goodwin model. Conditions in which the detailed mechanism is well approximated by the Goodwin model are given. A variant of the Goodwin model which displays sharp thresholds and relaxation oscillations is also explained by a double phosphorylation/dephosphorylation-based mechanism through a bistable behavior. These results not only provide rational support for the Goodwin model but also highlight the crucial role of the speed of post-translational processes, whose response curve are usually established at a steady state, in biochemical oscillators.

Effects of forage types on digestibility, methane emissions, and nitrogen utilization efficiency in two genotypes of hill ewes.

Science.gov (United States)

Zhao, Y G; Annett, R; Yan, T

2017-08-01

Thirty-six nonpregnant hill ewes (18 pure Scottish Blackface and 18 Swaledale × Scottish Blackface) aged 18 mo and weighing 48 ± 4.8 kg were allocated to 3 forage treatments balanced for genotype and BW. Each genotype was offered 3 forages (pelleted ryegrass, fresh lowland grass, and fresh hill grass) ad libitum with 6 ewes for each of the 6 genotype × diet combination treatments. Pelleted ryegrass was sourced from a commercial supplier (Drygrass South Western Ltd, Burrington, UK). Fresh lowland grass was harvested daily in the morning from a third regrowth perennial ryegrass () sward. Fresh hill grass was harvested from a seminatural hill grassland every 2 d and stored in plastic bags at 4 to 5°C until offered. The animals were individually housed in pens and offered experimental diets for 14 d before being transferred to 6 individual respiration chambers for a further 4 d, during which feed intake, fecal and urine outputs, and CH emissions were measured. There was no interaction between genotype and forage types on any variable measured. In a comparison of effects of the 3 forages, pelleted ryegrass had the greatest ( reduce CH emissions per kilogram DMI. These equations add new information in predicting enteric CH emissions and N utilization efficiency and can be used to quantify the environmental footprint of hill sheep production systems.

Eagle Hill, Kenya: changes over 60 years | Thomsett | Scopus ...

African Journals Online (AJOL)

Eagle Hill, the study site of the late Leslie Brown, was first surveyed over 60 years ago in 1948. The demise of its eagle population was near-complete less than 50 years later, but significantly, the majority of these losses occurred in the space of a few years in the late 1970s. Unfortunately, human densities and land use ...

Systematic studies of Bornean Zingiberaceae V. Zingiberoideae of Lambir Hills, Sarawak

NARCIS (Netherlands)

Sakai, S.; Nagamasu, H.

2006-01-01

This paper reports the subfamily Zingiberoideae (Zingiberaceae) of Lambir Hills National Park, Sarawak, Malaysia. Twelve species representing Boesenbergia, Globba, and Zingiber are recorded. Systematic and ecological notes are provided, and the key to the Bornean species of Boesenbergia is updated.

Establishment of Eucalyptus grandis W. Hill ex Maiden in vitro using ...

African Journals Online (AJOL)

Establishment of Eucalyptus grandis W. Hill ex Maiden in vitro using commercial products for seed treatment. Moacir Ribeiro Neto, Cíntia de Oliveira Martendal, Flávia Dionísio Pereira, Edson Luiz Souchie, Fabiano Guimarães Silva ...

The Effect of the Cherry Hill Study Skills Program on Eighth Grade Students' Reading Comprehension and Study Skills.

Science.gov (United States)

La Marca, Marilyn Tierney

A study was conducted to determine the effects of the "Cherry Hill Study Skills Program" on eighth grade students' reading comprehension and study skills. The "Cherry Hill Study Skills Program" is a process oriented course dealing with the sequential development of nine specific skills deemed essential to the retrieval and retention of information…

Geochemistry of core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG number-sign 3, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Peterman, Z.E.; Futa, K.

1996-01-01

The Tiva Canyon Tuff of Miocene age is composed of crystal-poor, high-silica rhyolite overlain by a crystal-rich zone that is gradational in composition from high-silica rhyolite to quartz latite. Each of these zones is divided into subzones that have distinctive physical, mineralogical, and geochemical features.Accurate identification of these subzones and their contacts is essential for detailed mapping and correlation both at the surface and in the subsurface in drill holes and in the exploratory studies facility (ESF). This report presents analyses of potassium (K), calcium (Ca), titanium (Ti), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), barium (Ba), lanthanum (La), and cerium (Ce) in core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG number-sign 3. The concentrations of most of these elements are remarkably constant throughout the high-silica rhyolite, but at its upper contact with the crystal-rich zone, Ti, Zr, Ba, Ca, Sr, La, Ce, and K begin to increase progressively through the crystal-rich zone. In contrast, Rb and Nb decrease, and Y remains essentially constant. Initial 87 Sr/ 86 Sr ratios are relatively uniform in the high-silica rhyolite with a mean value of 0.7117, whereas initial 87 Sr/ 86 Sr ratios decrease upward in the quartz latite to values as low as 0.7090

Reaction of Topopah Spring tuff with J-13 water: a geochemical modeling approach using the EQ3/6 reaction path code

International Nuclear Information System (INIS)

Delany, J.M.

1985-01-01

EQ3/6 geochemical modeling code package was used to investigate the interaction of the Topopah Spring Tuff and J-13 water at high temperatures. EQ3/6 input parameters were obtained from the results of laboratory experiments using USW G-1 core and J-13 water. Laboratory experiments were run at 150 and 250 0 C for 66 days using both wafer-size and crushed tuff. EQ3/6 modeling reproduced results of the 150 0 C experiments except for a small increase in the concentration of potassium that occurs in the first few days of the experiments. At 250 0 C, the EQ3/6 modeling reproduced the major water/rock reactions except for a small increase in potassium, similar to that noted above, and an overall increase in aluminum. The increase in potassium concentration cannot be explained at this time, but the increase in A1 concentration is believed to be caused by the lack of thermodynamic data in the EQ3/6 data base for dachiardite, a zeolite observed as a run product at 250 0 C. The ability to reproduce the majority of the experimental rock/water interactions at 150 0 C validates the use of EQ3/6 as a geochemical modeling tool that can be used to theoretically investigate physical/chemical environments in support of the Waste Package Task of NNWSI

The age of volcanic tuffs from the Upper Freshwater Molasse (North Alpine Foreland Basin) and their possible use for tephrostratigraphic correlations across Europe for the Middle Miocene

Science.gov (United States)

Rocholl, Alexander; Schaltegger, Urs; Gilg, H. Albert; Wijbrans, Jan; Böhme, Madelaine

2018-03-01

The Middle Miocene Upper Freshwater Molasse sediments represent the last cycle of clastic sedimentation during the evolution of the North Alpine Foreland Basin. They are characterized by small-scale lateral and temporal facies changes that make intra-basin stratigraphic correlations at regional scale difficult. This study provides new U-Pb zircon ages as well as revised 40Ar/39Ar data of volcanic ash horizons in the Upper Freshwater Molasse sediments from southern Germany and Switzerland. In a first and preliminary attempt, we propose their possible correlation to other European tephra deposits. The U-Pb zircon data of one Swiss (Bischofszell) and seven southern German (Zahling, Hachelstuhl, Laimering, Unterneul, Krumbad, Ponholz) tuff horizons indicate eruption ages between roughly 13.0 and 15.5 Ma. The stratigraphic position of the Unterneul and Laimering tuffs, bracketing the ejecta of the Ries impact (Brockhorizon), suggests that the Ries impact occurred between 14.93 and 15.00 Ma, thus assigning the event to the reversed chron C5Bn1r (15.032-14.870 Ma) which is in accordance with paleomagnetic evidence. We combine our data with published ages of tuff horizons from Italy, Switzerland, Bavaria, Styria, Hungary, and Romania to derive a preliminary tephrochronological scheme for the Middle Miocene in Central Europe in the age window from 13.2 to 15.5 Ma. The scheme is based on the current state of knowledge that the Carpathian-Pannonian volcanic field was the only area in the region producing explosive calc-alkaline felsic volcanism. This preliminary scheme will require verification by more high-quality ages complemented by isotopic, geochemical and paleomagnetic data.

Specification of a test problem for HYDROCOIN [Hydrologic Code Intercomparison] Level 3 Case 2: Sensitivity analysis for deep disposal in partially saturated, fractured tuff

International Nuclear Information System (INIS)

Prindle, R.W.

1987-08-01

The international Hydrologic Code Intercomparison Project (HYDROCOIN) was formed to evaluate hydrogeologic models and computer codes and their use in performance assessment for high-level radioactive waste repositories. Three principal activities in the HYDROCOIN Project are Level 1, verification and benchmarking of hydrologic codes; Level 2, validation of hydrologic models; and Level 3, sensitivity and uncertainty analyses of the models and codes. This report presents a test case defined for the HYDROCOIN Level 3 activity to explore the feasibility of applying various sensitivity-analysis methodologies to a highly nonlinear model of isothermal, partially saturated flow through fractured tuff, and to develop modeling approaches to implement the methodologies for sensitivity analysis. These analyses involve an idealized representation of a repository sited above the water table in a layered sequence of welded and nonwelded, fractured, volcanic tuffs. The analyses suggested here include one-dimensional, steady flow; one-dimensional, nonsteady flow; and two-dimensional, steady flow. Performance measures to be used to evaluate model sensitivities are also defined; the measures are related to regulatory criteria for containment of high-level radioactive waste. 14 refs., 5 figs., 4 tabs

Volcano-tectonic interaction at Soufriere Hills volcano, Montserrat (W.I.), constrained by dynamic gravity data

International Nuclear Information System (INIS)

Hautmann, Stefanie; Gottsmann, Joachim; Sparks, R Stephen J; Camacho, Antonio; Fournier, Nicolas

2008-01-01

We report on a joint gravimetric and ground deformation study on Montserrat, with the aim of quantifying mass and/or density changes beneath the island related to the volcanic activity at Soufrire Hills Volcano (SHV). Our observations coupled with 3-D data inversion indicate the existence of a previously unrecognised NNW-SSE trending zone of structural weakness (i.e. fault) that is located at shallow depths beneath the Centre Hills of Montserrat, along which active fluid migration is coupled to magmatic stressing at SHV.

Volcano-tectonic interaction at Soufriere Hills volcano, Montserrat (W.I.), constrained by dynamic gravity data

Energy Technology Data Exchange (ETDEWEB)

Hautmann, Stefanie; Gottsmann, Joachim; Sparks, R Stephen J [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ (United Kingdom); Camacho, Antonio [Instituto de AstronomIa y Geodesia (CSIC-UCM), Facultad CC Matematicas, Universidad Complutense Madrid, 28040 Madrid (Spain); Fournier, Nicolas [Seismic Research Unit, University of the West Indies, St Augustine (Trinidad and Tobago)], E-mail: stefanie.hautmann@googlemail.com

2008-10-01

We report on a joint gravimetric and ground deformation study on Montserrat, with the aim of quantifying mass and/or density changes beneath the island related to the volcanic activity at Soufrire Hills Volcano (SHV). Our observations coupled with 3-D data inversion indicate the existence of a previously unrecognised NNW-SSE trending zone of structural weakness (i.e. fault) that is located at shallow depths beneath the Centre Hills of Montserrat, along which active fluid migration is coupled to magmatic stressing at SHV.

Turbulence Models: Data from Other Experiments: FAITH Hill 3-D Separated Flow

Data.gov (United States)

National Aeronautics and Space Administration — Exp: FAITH Hill 3-D Separated Flow. This web page provides data from experiments that may be useful for the validation of turbulence models. This resource is...

The Changing Colors of Maple Hills: Intersections of Culture, Race, Language, and Exceptionality in a Rural Farming Community

Science.gov (United States)

Scanlan, Martin

2016-01-01

This case describes Maple Hills Elementary, a K-8 school in a rural farming community of the Midwest. As a community, Maple Hills has historically experienced a narrow range of diversity across race, ethnicity, language, and religion. Residents have predominantly been White, with German and English heritage, speak English as a mother tongue, and…

Cluster analysis on a sphere: Application to magnetizations from metasediments of the Jack Hills, Western Australia

Science.gov (United States)

Bono, Richard K.; Tarduno, John A.; Dare, Matthew S.; Mitra, Gautam; Cottrell, Rory D.

2018-02-01

Metasediments of the Jack Hills contain the oldest known terrestrial minerals in the form of zircons nearly 4.4 billion years old. Paleointensity data from these zircons provide evidence for a Hadean geodynamo as old as 4.2 billion years old. Given the importance of these zircons for constraining the earliest history of the core, it is vital to understand the fidelity of the zircon record. A fundamental aspect providing context for the preservation of primary magnetic signals is the nature of overprints predicted to have been imparted on rocks of the Jack Hills due to Archean to Proterozoic metamorphic events. To be viable magnetic records of a Hadean geodynamo, zircon magnetization directions should differ from these secondary magnetizations. To evaluate these secondary magnetizations, we report paleomagnetic analyses of a comprehensive sampling of 68 quartzite cobble-sized clasts from the Jack Hills metasediments ∼0.5 to 1.0 km from the Discovery Site (which has yielded the oldest zircons and paleofield estimates). While application of standard paleomagnetic tests suggests that the ensemble of cobble directions cannot be distinguished from those drawn from a random distribution, a new cluster analysis of directions on a sphere and non-parametric resampling approaches reveal significant directions amongst subsets of the data. One, isolated at the lowest temperature analyzed [200 to 300 °C, Declination (Dec.) = 316.8°, Inclination (Inc.) = - 51.1 °] appears to be dominated by the present day field. Another, isolated at higher (but still relatively low unblocking temperatures that we call "intermediate", of ∼350-500 °C, Dec. = 243.8°, Inc. = 9.5°) agrees with a magnetic overprint isolated from the secondary Cr-Fe mica fuchsite isolated from the Jack Hills Discovery site, passing a field test at the 80% confidence level. No evidence is found in our data, or in the data of others collected on similar Jack Hills lithologies, for a widespread 1 Ga

Geochemistry of PGE in mafic rocks of east Khasi Hills, Shillong ...

Indian Academy of Sciences (India)

study area. The studied mafic rocks of east Khasi Hills cover an area of about 4 km2 and represent .... In contrast to the global scenario, attempts for ..... chemical. Sp. no. structural mo de. Mineral comp o sition classification. M g#*. (wt%). (wt%).

Geoffrey Hill as Lord of Limit: the Kenosis as a Theological Context of his Poetry and Thought Note sur la kénose dans la poésie et la pensée de Geoffrey Hill

Directory of Open Access Journals (Sweden)

Adrian Grafe

2009-05-01

Full Text Available L’hymne kénotique pré-paulinienne (cf l’épître aux Philippiens, 2: 5-11 est un contexte pertinent pour situer la poésie et la poétique de Hill. Et la poésie et la prose de Hill montrent qu’il réfléchit sur cette notion (la kénose depuis au moins les sonnets de « Lachrimae » (1978 ; en passant par le titre et certains aspects du contenu de l’ouvrage critique The Lords of Limit (1984, ainsi que par l’appendice rédigé pour Christ : The Self-Emptying of God (1997 de Lucien Richard, jusqu’à The Triumph of Love (1998 et au-delà. Dans l’appendice de l’ouvrage de Richard, Hill évoque la « poésie kénotique » de Herbert, qui marie la maîtrise (la dimension seigneuriale et l’humilité (l’aspect limité. Dans la mesure où le terme « kénotique » est théologique, cette remarque sous-tend la lecture poético-théologique de l’œuvre de Hill lui-même qui est ici proposée sous une forme brève comme son titre l’indique.

Petrochemical variation of Topopah Spring tuff matrix with depth (stratigraphic level), drill hole USW G-4, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Byers, F.M. Jr.

1985-12-01

This study describes and interprets petrochemical variation of the matrix (excluding fractures and large gas cavities) of the Topopah Spring Member of the Paintbrush Tuff. This tuff includes the candidate host rock for a high-level nuclear waste repository at Yucca Mountain on the Nevada Test Site. Cored hole USW G-4, near the site of a potential exploratory shaft at Yucca Mountain, penetrated 359.4 m (1179 ft) of the member within the unsaturated zone. This study shows that petrographic textures and chemistry of the matrix vary systematically within recognizable lithologic subunits related to crystallization (cooling) zones, welding (compaction) zones, and compositional zones (rhyolite versus quartz latite). The methods used for this study include petrographic modal thin section analysis using an automated counter and electron microprobe analysis of the groundmass. Distinctive textural categories are defined, and they can be ranked from finest to coarsest as vitrophyre (glass), cryptocrystalline groundmass, spherulites, granophyre, lithic fragments, and phenocrysts. The two main groundmass compositions are also defined: rhyolite high silica) and quartz latite. The value of these petrochemical studies lies in providing microscopic criteria for recognizing the zonal subunits where they may have greatly limited exposure, as in mined drifts and in core from horizontal drill holes. For example, the lower nonlithophysal zone can be distinguished microscopically from the middle nonlithophysal zone by (1) degree of compaction, (2) amount of quartz, and (3) amount of lithic fragments. The variability between these textural categories should also be considered in designing physical and chemical tests of the Topopah Spring