Biot Critical Frequency Applied to Description of Failure and Yield of Highly Porous Chalk with Different Pore Fluids

DEFF Research Database (Denmark)

Andreassen, Katrine Alling; Fabricius, Ida Lykke

2010-01-01

Injection of water into chalk hydrocarbon reservoirs has led to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. In case of water-saturated samples, the concentration...... is controlled by solid-fluid friction. The reference frequency is thus a measure of this friction, and we propose that the fluid effect on mechanical properties of chalk may be the result of liquid-solid friction. We reviewed 622 published experiments on mechanical properties of porous chalk. The data include...... chalk samples that were tested at temperatures from 20 °C to 130 °C with the following pore fluids: fresh water, synthetic seawater, glycol, and oil of varying viscosity. The critical frequency is calculated for each experiment. For each specimen, we calculate the thickness to the slipping plane outside...

Potential for isoproturon, atrazine and mecoprop to be degraded within a chalk aquifer system

Science.gov (United States)

Johnson, Andrew C.; White, Craig; Lal Bhardwaj, C.

2000-06-01

The potential for herbicide degradation in an unconfined chalk aquifer was examined by collecting and spiking fresh samples and incubating them in the laboratory. The microcosms were incubated at 20°C under aerobic conditions and spiked with either isoproturon, atrazine or mecoprop at a concentration of 100 μg/l. The samples were obtained from a single fieldsite within the Upper Chalk aquifer in Hampshire, UK. Groundwater samples required the presence of sterile chalk in a ratio of at least 1:13 to promote isoproturon degradation. An isoproturon degradation potential existed in the soil, and the chalk unsaturated and saturated zones. However, no degradation of isoproturon in the unsaturated zone was observed when a more appropriate simulation of in-situ moisture conditions was carried out. Apart from the soil, no potential for atrazine or mecoprop degradation could be detected in the same samples over a 200-day incubation. In a series of groundwater samples taken from different boreholes, 10-300 m apart, large differences in isoproturon degradation potential were observed. Removal rates for 100 μg/l isoproturon varied from 83-425 ng/day, but in some samples no degradation potential could be detected. The primary metabolite which could be distinguished from isoproturon degradation in chalk and groundwater was monodesmethyl-isoproturon. When a chalk groundwater sample was spiked with isoproturon at 0.9 μg/l, this was not degraded over a 300-day incubation period. Further experiments with fresh groundwater from a Triassic Sandstone site illustrated that groundwater bacteria could degrade isoproturon at the more realistic temperature of 10°C as well as at 20°C.

Chalk as a reservoir

DEFF Research Database (Denmark)

Fabricius, Ida Lykke

, and the best reservoir properties are typically found in mudstone intervals. Chalk mudstones vary a lot though. The best mudstones are purely calcitic, well sorted and may have been redeposited by traction currents. Other mudstones are rich in very fine grained silica, which takes up pore space and thus...... basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... have hardly any stylolites and can have porosity above 40% or even 50% and thus also have relatively high permeability. Such intervals have the problem though, that increasing effective stress caused by hydrocarbon production results in mechanical compaction and overall subsidence. Most other chalk...

Uranium traps in the phosphate bearing sudr chalk, in northeastern sinai, Egypt

International Nuclear Information System (INIS)

Hussein, H.A.; El-Aassy, I.E.; Mahdy, M.A.; Dabbour, G.A.; Mansour, M.Gh.; Morsy, A.M.

1998-01-01

The maastrichtian sudr formation in northeastern sinai is composed of three members, the lower chalk, the middle phosphate and chart-bearing and the upper chalk members. Lemon yellow secondary uranium mineralization, distributed in the lower chalk member and in some phosphate beds from the middle phosphate member are observed. The XRD analyses of some samples from the uranium bearing chalk and the phosphate beds showed the presence of the secondary uranium minerals carnotite, bergenite and upalite. The mode of uranium occurrences could be interpreted as a result of the phosphatic beds decomposition and their subjection to later diagenetic processes. Uranium leaching circulation from phosphate rocks led to the liberation of uranium from the phosphates, and vanadium from the bituminous material and clay minerals. These migrated and were deposited locally and within the underlying chalk beds which acted as a lithologic trap

Marine macrofossil communities in the uppermost Maastrichtian chalk of Stevns Klint, Denmark

DEFF Research Database (Denmark)

Hansen, Thomas; Surlyk, Finn

2014-01-01

Three successive marine habitats and their benthic macrofossil communities have been recognised and assessed in the uppermost Maastrichtian chalk of Stevns Klint, Denmark. The mound-bedded lower Sigerslev Member was deposited below the photic zone under the influence of persistent, non-erosive bo......Three successive marine habitats and their benthic macrofossil communities have been recognised and assessed in the uppermost Maastrichtian chalk of Stevns Klint, Denmark. The mound-bedded lower Sigerslev Member was deposited below the photic zone under the influence of persistent, non...

Regional hardening of Upper Cretaceous Chalk in eastern England, UK: trace element and stable isotope patterns in the Upper Cenomanian and Turonian Chalk and their significance

Science.gov (United States)

Jeans, Christopher V.; Long, Dee; Hu, Xiu-Fang; Mortimore, Rory N.

2014-12-01

The regional hardening of the Late Cenomanian to Early Turonian Chalk of the Northern Province of eastern England has been investigated by examining the pattern of trace elements and stable carbon and oxygen isotopes in the bulk calcite of two extensive and stratigraphically adjacent units each 4 to 5 m thick of hard chalk in Lincolnshire and Yorkshire. These units are separated by a sequence, 0.3-1.3 m thick, of variegated marls and clayey marls. Modelling of the geochemistry of the hard chalk by comparison with the Standard Louth Chalk, combined with associated petrographic and geological evidence, indicates that (1) the hardening is due to the precipitation of a calcite cement, and (2) the regional and stratigraphical patterns of geochemical variation in the cement are largely independent of each other and have been maintained by the impermeable nature of the thin sequence of the clay-rich marls that separate them. Two phases of calcite cementation are recognised. The first phase was microbially influenced and did not lithify the chalk. It took place predominantly in oxic and suboxic conditions under considerable overpressure in which the Chalk pore fluids circulated within the units, driven by variations in compaction, temperature, pore fluid pressure and local tectonics. There is evidence in central and southern Lincolnshire of the loss of Sr and Mgenriched pore fluids to the south during an early part of this phase. The second phase of calcite precipitation was associated with the loss of overpressure in probably Late Cretaceous and in Cenozoic times as the result of fault movement in the basement penetrating the overlying Chalk and damaging the seal between the two chalk units. This greatly enhanced grain pressures, resulting in grain welding and pressure dissolution, causing lithification with the development of stylolites, marl seams, and brittle fractures. Associated with this loss of overpressure was the penetration of the chalk units by allochthonous

Structural and Lithological Controls upon Fluid Migration within the Chalk and Upper Greensand Aquifers in the Chilterns and Lambourn Downs

OpenAIRE

Thompson, Sally

2002-01-01

The influence of lithological heterogeneities, structural discontinuities and discontinuity surface mineralisation upon groundwater migration within the Chalk and the Upper Greensand of southern England has been investigated. Lithological heterogeneities in the Chalk succession include marl seams, hardgrounds, tabular flints and nodular flints. Each of these heterogeneities has a lower intrinsic porosity and permeability than in the calcite rich chalk. The influence that each of these ...

Slope failure of chalk channel margins

DEFF Research Database (Denmark)

Gale, A.; Anderskouv, Kresten; Surlyk, Finn

2015-01-01

provide evidence for recurring margin collapse of a long-lived Campanian channel. Compressionally deformed and thrust chalk hardgrounds are correlated to thicker, non-cemented chalk beds that form a broad, gentle anticline. These chalks represent a slump complex with a roll-over anticline of expanded, non......-cemented chalk in the head region and a culmination of condensed hardgrounds in the toe region. Observations strongly suggest that the slumping represents collapse of a channel margin. Farther northwards, the contemporaneous succession shows evidence of small-scale penecontemporaneous normal faulting towards...

The effect of chalk on the finger-hold friction coefficient in rock climbing.

Science.gov (United States)

Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

2012-11-01

The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing.

Improved Oil Recovery in Chalk. Spontaneous Imbibition affected by Wettability, Rock Framework and Interfacial Tension

Energy Technology Data Exchange (ETDEWEB)

Milter, J.

1996-12-31

The author of this doctoral thesis aims to improve the oil recovery from fractured chalk reservoirs, i.e., maximize the area of swept zones and their displacement efficiencies. In order to identify an improved oil recovery method in chalk, it is necessary to study wettability of calcium carbonate and spontaneous imbibition potential. The thesis contains an investigation of thin films and wettability of single calcite surfaces. The results of thin film experiments are used to evaluate spontaneous imbibition experiments in different chalk types. The chalk types were described detailed enough to permit considering the influence of texture, pore size and pore throat size distributions, pore geometry, and surface roughness on wettability and spontaneous imbibition. Finally, impacts of interfacial tension by adding anionic and cationic surfactants to the imbibing water phase are studied at different wettabilities of a well known chalk material. 232 refs., 97 figs., 13 tabs.

Current oil and gas production from North American Upper Cretaceous chalks

Science.gov (United States)

Scholle, Peter A.

1977-01-01

Production of oil and natural gas from North American chalks has increased significantly during the past five years, spurred by the prolific production from North Sea chalks, as well as by higher prices and improved production technology. Chalk reservoirs have been discovered in the Gulf Coast in the Austin Group, Saratoga and Annona Chalks, Ozan Formation, Selma Group, Monroe gas rock (an informal unit of Navarro age), and other Upper Cretaceous units. In the Western Interior, production has been obtained from the Cretaceous Niobrara and Greenhorn Formations. Significant, though subcommercial, discoveries of natural gas and gas condensate also have been made in the Upper Cretaceous Wyandot Formation on the Scotian Shelf of eastern Canada. All North American chalk units share a similar depositional and diagenetic history. The chalks consist primarily of whole and fragmented coccoliths with subordinate planktonic and benthonic Foraminifera, inoceramid prisms, oysters, and other skeletal grains. Most have between 10 and 35 percent HCl-insoluble residue, predominantly clay. Deposition was principally below wave base in tens to hundreds of meters of water. The diagenetic history of a chalk is critical in determining its reservoir potential. All chalk has a stable composition (low-Mg calcite) and very high primary porosity. With subsequent burial, mechanical and chemical (solution-transfer) compaction can reduce or completely eliminate pore space. The degree of loss of primary porosity in chalk sections is normally a direct function of the maximum depth to which it has been buried. Pore-water chemistry, pore-fluid pressures, and tectonic stresses also influence rates of cementation. Oil or gas reservoirs of North American chalk fall into three main groups: 1. Areas with thin overburden and significant primary porosity retention (for example, Niobrara Formation of Kansas and eastern Colorado). 2. Areas with thicker overburden but considerable fracturing. Here primary

Quantitative 1D saturation profiles on chalk by NMR

DEFF Research Database (Denmark)

Olsen, Dan; Topp, Simon; Stensgaard, Anders

1996-01-01

Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...

Chalk effect on PVC cross-linking under irradiation

International Nuclear Information System (INIS)

Chudinova, V.V.; Guzeev, V.V.; Mozzhukhin, V.B.; Pomerantseva, Eh.G.; Nozrina, F.D.; Zhil'tsov, V.V.; Zubov, V.P.

1994-01-01

Effect of nonmodified and modified chalk on curing degree of polymer matrix was studied under-irradiation of PVC-compositions. Films of the compositions (100 mass part 7 PVC, 0-100 mas.part of chalk, 2.5 - lead sulfate, 1.5 - lead stearate and 0.3 - glycerin) were irradiated up to absorbed dose 0.1 MGy in an inert medium. Content of gel-fraction after boiling in THF was determined with use of IR spectroscopy. It was established, that intensive dehydrochlorination and polymer curing took place on chalk particle surface. Network fixed strongly chalk particles. However, chalk inhibited processes of dehydrochlorination and PVC curing, increasing amount of noncured PVC in polymer matrix

Microbial Fluid-Rock Interactions in Chalk Samples and Salinity Factor in Divalent Ca2+ ions Release for Microbial Enhanced Oil Recovery Purposes

DEFF Research Database (Denmark)

Jimoh, Ismaila Adetunji; Rudyk, Svetlana Nikolayevna; Søgaard, Erik Gydesen

2011-01-01

In this study, laboratory experiments were performed on chalk samples from Danish sector of the North Sea to study microbial fluid-rock interactions with carbonate rock and to evaluate the dissolution of rock matrix (CaCO3). Result showed that the average concentration of Ca2+ ions after microbia...

Adsorption Properties of Chalk Reservoir Materials

DEFF Research Database (Denmark)

Okhrimenko, Denis

/gas adsorption properties of synthetic calcium carbonate phases (calcite, vaterite and aragonite) with chalk, which is composed of biogenic calcite (>98%). In combination with data from nanotechniques, the results demonstrate the complexity of chalk behavior and the role of nanoscale clay particles. The results...

Chalk porosity and sonic velocity versus burial depth

DEFF Research Database (Denmark)

Fabricius, Ida Lykke; Gommesen, Lars; Krogsbøll, Anette Susanne

2008-01-01

Seventy chalk samples from four formations in the overpressured Danish central North Sea have been analyzed to investigate how correlations of porosity and sonic velocity with burial depth are affected by varying mineralogy, fluid pressure, and early introduction of petroleum. The results show th...... for fluid pressure because the cementing ions originate from stylolites, which are mechanically similar to fractures. We find that cementation occurs over a relatively short depth interval.......Seventy chalk samples from four formations in the overpressured Danish central North Sea have been analyzed to investigate how correlations of porosity and sonic velocity with burial depth are affected by varying mineralogy, fluid pressure, and early introduction of petroleum. The results show...... that porosity and sonic velocity follow the most consistent depth trends when fluid pressure and pore-volume compressibility are considered. Quartz content up to 10% has no marked effect, but more than 5% clay causes lower porosity and velocity. The mineralogical effect differs between P-wave and shear velocity...

Self Compacting Concrete with Chalk Filler

DEFF Research Database (Denmark)

Sørensen, Eigil V.

2007-01-01

Utilisation of Danish chalk filler has been investigated as a means to produce self compacting concrete (SCC) at lower strength levels for service in non aggressive environments. Stable SCC mixtures were prepared at chalk filler contents up to 60% by volume of binder to yield compressive strengths...

Field and numerical descriptions of fracture geometries and terminations in chalk containing chert layers and inclusions; implications for groundwater flow in Danish chalk aquifers

Science.gov (United States)

Seyum, S.

2017-12-01

This study is a description of the fracture distribution in laterally discontinuous chalk and chert layers, with an investigation on how fracture lengths and apertures vary as a function of applied stresses, material properties, and interface properties. Natural fractures intersect laterally extensive, discontinuous, chalk-chert material interfaces in 62 million-year old to 72 million-year old Chalk Group formations exposed at Stevns Klint, Denmark. Approximately one-third of Denmark's fresh water use is from chalk and limestone regional aquifers of the Chalk Group formations, where rock permeability is dominantly a function of open fracture connectivities. Fractured, centimeter- to decimeter-thick chert layers and inclusions (101 GPa elastic stiffness) are interlayered with fractured, meter-thick chalk layers (100 GPa elastic stiffness). Fractures are observed to terminate against and cross chalk-chert interfaces, affecting the vertical flow of water and pollutants between aquifers. The discontinuous and variably thin nature of chert layers at Stevns Klint effectively merges adjacent fracture-confining layers of chalk along discrete position intervals, resulting in lateral variability of fracture spacing. Finite element numerical models are designed to describe fracture interactions with stiff, chert inclusions of various shapes, thicknesses, widths, orientations, and interface friction and fracture toughness values. The models are two-dimensional with isotropic, continuous material in plane strain and uniformly applied remote principal stresses. These characteristics are chosen based on interpretations of the petrophysics of chalk and chert, the burial history of the rock, and the scale of investigation near fracture tips relative to grain sizes. The result are value ranges for relative stiffness contrasts, applied stresses, and material interface conditions that would cause fractures to cross, terminate at, or form along chalk-chert interfaces, with emphasis on

THE STUDY OF TECHNOLOGICAL PROPERTIES OF PLASTISOLS BASED EMULSION PVC FILLED WITH CHALK GIDROFOBIZIROVANNYM

Directory of Open Access Journals (Sweden)

V. A. Sedykh

2014-01-01

Full Text Available Baby toys are made using the centrifugal molding plastisol based emulsion of polyvinyl chloride plasticized with dioctylphthalate. To reduce cost and decrease biotelemetry the dioctylphthalate on the surface of the product domestic toys than toys produced in China, there was a necessity of introduction of the filler is chalk from different manufacturers. By using a Brookfield vis-cometer PV-D was studied rheology of filled hydrophobized chalk PVC plastisols in storage conditions for up to 72 hours at temperatures of 14-20°C. It was found that the flow plastisols consistent with pseudo-plastic fluids. Given the flow rates of emulsion PVC plastisols filled to 35 % of the mass. hydrophobized chalk. The influence of the content of the plasticizer dioctylphthalate in a narrow interval (37,0 - 41,4 % of the mass. on the viscosity of polymer pastes and the kinetics of its changes during storage. Revealed a linear dependence of the viscosity of the filled hydrophobized chalk plastisols on the speed of rotation of the spindle of the viscometer and during storage. Given the rate of expansion changes the viscosity of the plastisols of the speed of rotation of the spindle of the viscometer, the rate of change in viscosity and calculation of the initial viscosity. Determined the stability of the dispersion hydrophobized chalk in a colloidal solution of PVC in dioctylphthalate during storage. We determined the variation of the content of chalk (ash with top and bottom layers plastisols height 8 cm after 24 hours storage. It is proved that the temperature of the preparation and storage of polymer pastes were determining factors in the regulation of such technological properties of PVC plastisols in the presence hydrophobized chalkas viscosity, stability of the dispersion of chalk and, consequently, the efficiency of distribution plastisols in the form of a centrifugal molding.

Caoxite-hydroxyapatite composition as consolidating material for the chalk stone from Basarabi-Murfatlar churches ensemble

Science.gov (United States)

Ion, Rodica-Mariana; Turcanu-Caruţiu, Daniela; Fierăscu, Radu-Claudiu; Fierăscu, Irina; Bunghez, Ioana-Raluca; Ion, Mihaela-Lucia; Teodorescu, Sofia; Vasilievici, Gabriel; Rădiţoiu, Valentin

2015-12-01

The development of new composition for surface conservation of some architectural monuments represents now an important research topic. The Basarabi-Murfatlar Ensemble, recognized as the first religious monument from mediaeval Dobrogea (Romania) (from 9th to 11th century), is one of the most impressive archaeological sites of Europe. This ensemble is built from amorphous calcium carbonate, very sensitive to humidity, frost, salts, etc. The aim of this paper is to test on chalk stone samples a new consolidant - hydroxyapatite (HAp) mixed with calcium oxalate trihydrate (caoxite) (COT). Some specific techniques for evaluation its impact on chalk stone surface are used, as follows: petrographical and physical-chemical techniques: SEM, OM, ICP-AES, TGA, FTIR and Raman spectroscopy, chromatic parameters changes, the accelerated weathering tests: heating, freeze-thaw, and their effects on porosity and capillary water uptake by the chalk surface. All these have been evaluated before and after treatment with COT-HAp, putting into evidence the effect of the new composition on the chalk stone surface. HAp induces COT stabilization, and their joint composition can bind weathered stone blocks providing a substantial reinforcement of chalk surface.

Measurements with the Chalk River Calorimeters

International Nuclear Information System (INIS)

Boyd, A.W.

1970-01-01

The Chalk River calorimeters were designed to measure the absorbed dose rate in reactors in materials such as graphite, polyethylene and beryllium in the range 0.01-1 Wg -1 . To eliminate heaters in the sample they were made to operate adiabatically, or more accurately quasi-adiabatically since there is no heater on the jacket. Both the sample and jacket temperatures are recorded from the time of insertion in the reactor flux and the absorbed dose rate is calculated from these data. The advantages of this type of calorimeter are the ease of construction and the absence of a sample heater. The disadvantage is that dose rates below ~ 10 mWg -1 cannot be determined accurately

Managing Injected Water Composition To Improve Oil Recovery: A Case Study of North Sea Chalk Reservoirs

DEFF Research Database (Denmark)

Zahid, Adeel; Shapiro, Alexander; Stenby, Erling Halfdan

2012-01-01

of the temperature dependence of the oil recovery indicated that the interaction of the ions contained in brine with the rock cannot be the only determining mechanism of enhanced recovery. We observed no substitution of Ca2+ ions with Mg2+ ions at high temperatures for both rocks. Not only the injection brine......In recent years, many core displacement experiments of oil by seawater performed on chalk rock samples have reported SO42–, Ca2+, and Mg2+ as potential determining ions for improving oil recovery. Most of these studies were carried out with outcrop chalk core plugs. The objective of this study...... is to investigate the potential of the advanced waterflooding process by carrying out experiments with reservoir chalk samples. The study results in a better understanding of the mechanisms involved in increasing the oil recovery with potential determining ions. We carried out waterflooding instead of spontaneous...

Seismic architecture of the Chalk Group from onshore reflection data in eastern Denmark

DEFF Research Database (Denmark)

Moreau, Julien; Anderskouv, Kresten; Boldreel, Lars Ole

with the seismic stratigraphy. Several seismic facies are identified in the Chalk Group: the 'transparent' (white chalk), the stratified (marl-chalk alternations), the crudely stratified (flint-rich chalk) and the hummocky (bryozoan mounds). The units notably vary in thickness at a relatively small scale...... of the deformations appear to be restricted to the white chalk, whereas the stratified seismic facies are comparatively less disturbed. The origin of the structures observed in the white chalk can either be associated with the regional stress field or with differential diagenetic evolution between strata inducing...

The fusion blanket program at Chalk River

International Nuclear Information System (INIS)

Hastings, I.J.

1986-03-01

Work on the Fusion Blanket Program commenced at Chalk River in 1984 June. Co-funded by Canadian Fusion Fuels Technology Project and Atomic Energy of Canada Limited, the Program utilizes Chalk River expertise in instrumented irradiation testing, ceramics, tritium technology, materials testing and compound chemistry. This paper gives highlights of studies to date on lithium-based ceramics, leading contenders for the fusion blanket

Imaging the Danish Chalk Group with high resolution, 3-component seismics

Science.gov (United States)

Kammann, J.; Rasmussen, S. L.; Nielsen, L.; Malehmir, A.; Stemmerik, L.

2016-12-01

The Chalk Group in the Danish Basin forms important reservoirs to hydrocarbons as well as water resources, and it has been subject to several seismic studies to determine e.g. structural elements, deposition and burial history. This study focuses on the high quality seismic response of a survey acquired with an accelerated 45 kg weight drop and 3-component MEMS-based sensors and additional wireless vertical-type sensors. The 500 m long profile was acquired during one day close to a chalk quarry and chalk cliffs of the Stevns peninsula in eastern Denmark where the well-known K-T (Cretaceous-Tertiary) boundary and different chalk lithologies are well-exposed. With this simple and fast procedure we were able to achieve deep P-wave penetration to the base of the Chalk Group at about 900 m depth. Additionally, the CMP-processed seismic image of the vertical component stands out by its high resolution. Sedimentary features are imaged in the near-surface Danian, as well as in the deeper Maastrichtian and Upper Campanian parts of the Chalk Group. Integration with borehole data suggests that changes in composition, in particular clay content, correlate with changes in reflectivity of the seismic data set. While the pure chalk in the Maastrichtian deposits shows rather low reflectivity, succession enriched in clay appear to be more reflective. The integration of the mentioned methods gives the opportunity to connect changes in facies to the elastic response of the Chalk Group in its natural environmental conditions.

Chalk: composition, diagenesis and physical properties

DEFF Research Database (Denmark)

Fabricius, Ida Lykke

2007-01-01

Chalk is a sedimentary rock of unusually high homogeneity on the scale where physical properties are measured, but the properties fall in wide ranges. Chalk may thus be seen as the ideal starting point for a physical understanding of rocks in general. Properties as porosity, permeability, capillary...... involving clay, silica, and calcite are interlinked, but progress differently in different localities. This partly depends on primary sediment composition, including organic content, which may induce the formation of concretions by microbial action. The diagenetic processes also depend on water depth, rate...

Low field NMR surface relaxivity studies of chalk and argillaceous sandstones

DEFF Research Database (Denmark)

Katika, Konstantina; Fordsmand, Henrik; Fabricius, Ida Lykke

2017-01-01

the accuracy of predictions of petrophysical properties of various rocks with the use of NMR spectrometry. We perform laboratory transverse relaxation (T2) measurements on water saturated Gorm field chalk, Stevns Klint chalk, Solsort field greensand and Berea sandstone. These rocks are of particular interest...... field chalk and Solsort field greensand have higher ρ at higher Larmor frequency. By contrast, ρ of the purely calcitic Stevns chalk and quartzitic Berea sandstone proved not to be affected by the changes in frequency. T2 distributions at temperatures ranging from 10 °C to 60 °C provided comparison...

Effect of Fluid Dynamic Viscosity on the Strength of Chalk

DEFF Research Database (Denmark)

Hedegaard, K.; Fabricius, Ida Lykke

The mechanical strength of high porosity and weakly cemented chalk is affected by the fluid in the pores. In this study, the effect of the dynamic viscosity of non-polar fluids has been measured on outcrop chalk from Sigerslev Quarry, Stevns, Denmark. The outcome is that the measured strength...... of the chalk decreases with increasing dynamic viscosity. The proposed qualitative explanation is that pressure difference supports and enhances the generation of microscopic shear and tensile failures....

Can we get a better knowledge on dissolution processes in chalk by using microfluidic chips?

Science.gov (United States)

Neuville, Amélie; Minde, Mona; Renaud, Louis; Vinningland, Jan Ludvig; Dysthe, Dag Kristian; Hiorth, Aksel

2017-04-01

This work has been initiated in the context of research on improving the oil recovery in chalk bedrocks. One of the methods to improve the oil recovery is to inject "smart water" (acidic water/brines). Experiments on core scale and field tests that have been carried out the last decade have clearly shown that water chemistry affects the final oil recovery. However, there is generally no consensus in the scientific community of why additional oil is released, and it is also still not understood what are the mineralogical and structural changes. Direct in situ observation of the structural changes that occur when chalk is flooded with brines could resolve many of the open questions that remain. One of the highlights of this work is thus the development of an innovative methodology where fluid/rock interactions are observed in-situ by microscopy. To do so, we create several types of custom-made microfluidic systems that embeds reactive materials like chalk and calcite. The methodology we develop can be applied to other reactive materials. We will present an experiment where a calcite window dissolves with a fluid, where we observe in-situ the topography features of the calcite window, as well as the dissolution rate [1]. The injected fluid circulates at controlled flowrates in a channel which is obtained by xurography: double sided tape is cut out with a cutter plotter and placed between the reactive window and a non-reactive support. While the calcite window reacts, its topography is measured in situ every 10 s using an interference microscope, with a pixel resolution of 4.9 μm and a vertical resolution of 50 nm. These experiments are also compared with reactive flow simulations done with Lattice Boltzmann methods. Then, we will present a dissolution experiment done with a microfluidic system that embeds chalk. In this experiment, the main flow takes place at the chalk surface, in contact with fluid flowing in a channel above the chalk sample. Thus the reaction

Wettability of Chalk and Argillaceous Sandstones Assessed from T1/T2 Ratio

DEFF Research Database (Denmark)

Katika, Konstantina; Saidian, M.; Fabricius, Ida Lykke

ratio can quantify the affinity between the rock and wetting pore fluid. The affinity is a measure directly linked to wettability. In order to investigate the T2-shortening, we performed T1-T2 NMR experiments on different samples of chalk, Berea sandstone, and chloritic greensand, saturated either...... with water, oil or oil/water at irreducible water saturation. The T1/T2 ratio obtained from T1-T2 maps reflects the T2-shortening. We compare the T1/T2 ratio for the same type of rock, saturated with different fluids. The chalk shows high affinity for water, Berea sandstone has no clear preference for oil...

Using Raman spectroscopic imaging for non-destructive analysis of filler distribution in chalk filled polypropylene

DEFF Research Database (Denmark)

Boros, Evelin; Porse, Peter Bak; Nielsen, Inga

2016-01-01

A feasibility study on using Raman spectral imaging for visualization and analysis of filler distribution in chalk filled poly-propylene samples has been carried out. The spectral images were acquired using a Raman spectrometer with 785 nm light source.Eight injection-molded samples with concentr...

Change of Static and Dynamic Elastic Properties due to CO² Injection in North Sea Chalk

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Hjuler, M.L.; Christensen, H.F.

2012-01-01

important in enhanced oil recovery by CO2 injection (CO2-EOR) in chalk as, chalk reservoirs are vulnerable to compaction under changed stress and pore fluid. From South Arne field, North Sea, we used Ekofisk Formation chalk having approximately 20% non-carbonate and Tor Formation chalk having less than 5...

Burial diagenesis of deep sea chalk as reflected in Biot's coefficient

DEFF Research Database (Denmark)

Fabricius, Ida Lykke; Alam, Mohammad Monzurul

2013-01-01

to limestone as burial increases and porosity decreases. The porosity decrease is accompanied by an increasing velocity to elastic waves, and consequently a decreasing Biot's coefficient, as estimated from velocity and density of core samples. When the effective burial stress is normalized to total horizontal....... In the ooze, we find that the natural compaction causes an increasing stress on grain contact area, indicating that the ooze particles become strongly strained. In the chalk section, contact cement is probably the reason why particles become less strained as porosity declines. In the limestone, stress...... on particles apparently is low and not correlated with porosity, probably because the pore-filling cementation in this interval causes Biot's coefficient to decline as burial increases. Limestone from the water zone of the North sea Chalk Group follows the same stress trend as deep sea limestone. These results...

Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged

2011-01-01

Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation...... and Tor Formation chalk of the South Arne field to reveal the changes in petrophysical and rock mechanics properties of chalk due to the injection of CO2 at supercritical state. An increase in porosity and decrease in specific surface was observed due to injection of supercritical CO2. This indicates...... as indicated by NMR T2 relaxation time was observed. Rock mechanics testing indicates that in 30% porosity chalk from the South Arne field, injection of supercritical CO2 has no significant effect on shear strength and compaction properties, while there is probably a slight decrease in stiffness properties...

Dissection of genetic architecture of grain chalk using NIR spectroscopy

Science.gov (United States)

Chalk is a major quality characteristic that causes grain breakage during milling and loss of crop value. In this study, we sought to elucidate the quantitatively inherited grain chalk trait in rice and to conduct genome-wide association mapping to identify SNPs and candidate genes associated with ...

Water in chalk reservoirs: 'friend or foe?'

International Nuclear Information System (INIS)

Hjuler, Morten Leth

2004-01-01

Most of the petroleum fields in the Norwegian sector of the North Sea are sandstone reservoirs; the oil and gas are trapped in different species of sandstone. But the Ekofisk Field is a chalk reservoir, which really challenges the operator companies. When oil is produced from chalk reservoirs, water usually gets in and the reservoir subsides. The subsidence may be expensive for the oil companies or be used to advantage by increasing the recovery rate. Since 60 per cent of the world's petroleum reserves are located in carbonate reservoirs, it is important to understand what happens as oil and gas are pumped out. Comprehensive studies at the Department of Petroleum Technology and Applied Geophysics at Stavanger University College in Norway show that the mechanical properties of chalk are considerably altered when the pores in the rock become saturated with oil/gas or water under different stress conditions. The processes are extremely complex. The article also maintains that the effects of injecting carbon dioxide from gas power plants into petroleum reservoirs should be carefully studied before this is done extensively

Rock physical aspects of CO{sub 2} injection in chalk

Energy Technology Data Exchange (ETDEWEB)

Alam, M.M.

2011-04-15

Impact of supercritical CO{sub 2} on the petrophysical and rock-mechanics properties of Ekofisk Formation and Tor Formation chalk from South Arne field, Danish North Sea, chalk was investigated. A series of laboratory experiments was performed on core material collected from the reservoir zone of the South Arne field in order to reveal the changes with respect to porosity, specific surface, pore stiffness, wettability, mineralogy and mechanical failure. In addition, a theoretical rock physical background was also established in order to be able to make sensible interpretation of laboratory data. Sound wave velocity was used as the central tool to study any change in petrophysical and rock mechanical properties. The main focus was to achieve a better understanding of effective stress coefficient (also known as Biot's coefficient); by means of which effective stress can be predicted more accurately. Independent theoretical studies were made on diagenesis, surface properties and stiffness of chalk and their relation with sonic velocity (or Biot's coefficient calculated from sonic velocity). The knowledge and experience from these studies was combined to achieve the main research objective of monitoring changes in hydrocarbon reservoirs in chalk due to CO{sub 2} injection. In order to understand the development of chalk from calcareous ooze and achieving pore stiffness, the diagenesis process of a sedimentary sequence from Kerguelen Plateau in the Indian Ocean was studied. The principal objective of the study was to explore how different porosity reduction mechanisms change the strength of these deep sea carbonate-rich sediments and how these mechanisms can be traced from the change in Biot's coefficient, alpha. In calcareous ooze, alpha was found close to one. Mechanical compaction reduces porosity, but only leads to a minor decrease in alpha. Recrystallization process renders particles smoother, but do not lead to reduction in alpha unless it gives

Response of invertebrates from the hyporheic zone of chalk rivers to eutrophication and land use.

Science.gov (United States)

Pacioglu, Octavian; Moldovan, Oana Teodora

2016-03-01

Whereas the response of lotic benthic macroinvertebrates to different environmental stressors is a widespread practice nowadays in assessing the water and habitat quality, the use of hyporheic zone invertebrates is still in its infancy. In this study, classification and regression trees analysis were employed in order to assess the ecological requirements and the potential as bioindicators for the hyporheic zone invertebrates inhabiting four lowland chalk rivers (south England) with contrasting eutrophication levels (based on surface nitrate concentrations) and magnitude of land use (based on percentage of fine sediments load and median interstitial space). Samples of fauna, water and sediment were sampled twice, during low (summer) and high (winter) groundwater level, at depths of 20 and 35 cm. Certain groups of invertebrates (Glossosomatidae and Psychomyiidae caddisflies, and riffle beetles) proved to be good indicators of rural catchments, moderately eutrophic and with high fine sediment load. A diverse community dominated by microcrustaceans (copepods and ostracods) were found as good indicators of highly eutrophic urban streams, with moderate-high fine sediment load. However, the use of other taxonomic groups (e.g. chironomids, oligochaetes, nematodes, water mites and the amphipod Gammarus pulex), very widespread in the hyporheic zone of all sampled rivers, is of limited use because of their high tolerance to the analysed stressors. We recommend the use of certain taxonomic groups (comprising both meiofauna and macroinvertebrates) dwelling in the chalk hyporheic zone as indicators of eutrophication and colmation and, along with routine benthic sampling protocols, for a more comprehensive water and habitat quality assessment of chalk rivers.

Process for treating oil-chalk

Energy Technology Data Exchange (ETDEWEB)

1925-10-20

A process for treating oil-chalk or similar oil-containing minerals is characterized in that the material is treated in a stream of air diluted with indifferent gases at a temperature of about 150/sup 0/ to 160/sup 0/C.

The sedimentology of redeposited chalk

DEFF Research Database (Denmark)

Anderskouv, Kresten; Surlyk, Finn; Gale, Andy

Redeposited facies in the Upper Cretaceous Chalk Group constitute major hydrocarbon reservoirs in the North Sea Central Graben. Existing facies models are largely based on publications from the early 1980's dealing with core material from the Norwegian sector. However, the recognition, interpreta...

Twelve tips for the production of digital chalk-talk videos.

Science.gov (United States)

Rana, Jasmine; Besche, Henrike; Cockrill, Barbara

2017-06-01

Increasingly over the past decade, faculty in medical and graduate schools have received requests from digital millennial learners for concise faculty-made educational videos. At our institution, over the past couple of years alone, several hundred educational videos have been created by faculty who teach in a flipped-classroom setting of the pre-clinical medical school curriculum. Despite the appeal and potential learning benefits of digital chalk-talk videos first popularized by Khan Academy, we have observed that the conceptual and technological barriers for creating chalk-talk videos can be high for faculty. To this end, this tips article offers an easy-to-follow 12-step conceptual framework to guide at-home production of chalk-talk educational videos.

Chalk effect on PVC cross-linking under irradiation; Vliyanie mela na sshivanie PVKh pri obluchenii

Energy Technology Data Exchange (ETDEWEB)

Chudinova, V V; Guzeev, V V; Mozzhukhin, V B; Pomerantseva, Eh G; Nozrina, F D; Zhil` tsov, V V; Zubov, V P

1994-12-31

Effect of nonmodified and modified chalk on curing degree of polymer matrix was studied under-irradiation of PVC-compositions. Films of the compositions (100 mass part 7 PVC, 0-100 mas.part of chalk, 2.5 - lead sulfate, 1.5 - lead stearate and 0.3 - glycerin) were irradiated up to absorbed dose 0.1 MGy in an inert medium. Content of gel-fraction after boiling in THF was determined with use of IR spectroscopy. It was established, that intensive dehydrochlorination and polymer curing took place on chalk particle surface. Network fixed strongly chalk particles. However, chalk inhibited processes of dehydrochlorination and PVC curing, increasing amount of noncured PVC in polymer matrix.

Dual hydraulic behaviour of the Chalk in the Netherlands North Sea

NARCIS (Netherlands)

Verweij, H.

2006-01-01

Information on the sedimentary development, seismic stratigraphy and burial compaction of the Chalk Group in the Netherlands North Sea was combined with pressure data and basin modelling to investigate the hydraulic behaviour of the Chalk Group in the Central Graben and Schill Grund High. The

Advanced waterflooding in chalk reservoirs: Understanding of underlying mechanisms

DEFF Research Database (Denmark)

Zahid, Adeel; Sandersen, Sara Bülow; Stenby, Erling Halfdan

2011-01-01

Over the last decade, a number of studies have shown SO42−, Ca2+ and Mg2+ to be potential determining ions, which may be added to the injected brine for improving oil recovery during waterflooding in chalk reservoirs. However the understanding of the mechanism leading to an increase in oil recove...... of a microemulsion phase could be the possible reasons for the observed increase in oil recovery with sulfate ions at high temperature in chalk reservoirs besides the mechanism of the rock wettability alteration, which has been reported in most previous studies.......Over the last decade, a number of studies have shown SO42−, Ca2+ and Mg2+ to be potential determining ions, which may be added to the injected brine for improving oil recovery during waterflooding in chalk reservoirs. However the understanding of the mechanism leading to an increase in oil recovery...

Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France

International Nuclear Information System (INIS)

Lapworth, D.J.; Baran, N.; Stuart, M.E.; Manamsa, K.; Talbot, J.

2015-01-01

The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n = 16), pesticides (n = 14) and pharmaceuticals, personal care and lifestyle products (n = 12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings. - Highlights: • Broad range of microorganics detected in Chalk groundwater in England and France. • Plasticisers, pesticides, BPA and THM detected at the highest concentrations. • Pesticides higher in outcrop Chalk, caffeine and BPA at concealed sites. • Occurrences show some relationship to land use, borehole depth and water level. - Broad screening reveals for the first time the extent of emerging microorganic pollution in Chalk groundwater sources across England and France

Dynamic and static elastic moduli of North Sea and deep sea chalk

DEFF Research Database (Denmark)

Gommesen, Lars; Fabricius, Ida Lykke

2001-01-01

We have established an empirical relationship between the dynamic and the static mechanical properties of North Sea and deep sea chalk for a large porosity interval with respect to porosity, effective stress history and textural composition. The chalk investigated is from the Tor and Hod Formatio...

Isotope hydrology of the Chalk River Laboratories site, Ontario, Canada

Science.gov (United States)

Peterman, Zell; Neymark, Leonid; King-Sharp, K.J.; Gascoyne, Mel

2016-01-01

This paper presents results of hydrochemical and isotopic analyses of groundwater (fracture water) and porewater, and physical property and water content measurements of bedrock core at the Chalk River Laboratories (CRL) site in Ontario. Density and water contents were determined and water-loss porosity values were calculated for core samples. Average and standard deviations of density and water-loss porosity of 50 core samples from four boreholes are 2.73 ± 12 g/cc and 1.32 ± 1.24 percent. Respective median values are 2.68 and 0.83 indicating a positive skewness in the distributions. Groundwater samples from four deep boreholes were analyzed for strontium (87Sr/86Sr) and uranium (234U/238U) isotope ratios. Oxygen and hydrogen isotope analyses and selected solute concentrations determined by CRL are included for comparison. Groundwater from borehole CRG-1 in a zone between approximately +60 and −240 m elevation is relatively depleted in δ18O and δ2H perhaps reflecting a slug of water recharged during colder climatic conditions. Porewater was extracted from core samples by centrifugation and analyzed for major dissolved ions and for strontium and uranium isotopes. On average, the extracted water contains 15 times larger concentration of solutes than the groundwater. 234U/238U and correlation of 87Sr/86Sr with Rb/Sr values indicate that the porewater may be substantially older than the groundwater. Results of this study show that the Precambrian gneisses at Chalk River are similar in physical properties and hydrochemical aspects to crystalline rocks being considered for the construction of nuclear waste repositories in other regions.

Radar sounding of bedrock and water table at Chalk River

International Nuclear Information System (INIS)

Annan, A.P.; Davis, J.L.

1979-01-01

When a spill of radioactive waste occurs, one of the main concerns is the flow pattern of ground water in the area of the spill. Ground probing radar is a relatively new geophysical technique which can provide high resolution data on the surficial geology and water distribution. The results of some preliminary radar experiments conducted at Chalk River Nuclear Laboratories (CRNL) of the Atomic Energy of Canada Limited (AECL), Chalk River, Ontario are presented. (auth)

Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

DEFF Research Database (Denmark)

Hassenkam, Tue; Skovbjerg, Lone Lindbæk; Stipp, Susan Louise Svane

2009-01-01

been drilled in a water-bearing formation. At this site, the chalk has never seen oil, though at other locations, the same stratigraphic horizon with the same rock properties is known to be a productive oil reservoir. Thus the properties of the investigated particle surfaces are inherent to the chalk......Ultimate Oil recovery from chalk reservoirs is limited by many factors - including the grain size and the surface properties of the small mainly biogenic calcite particles that chalk is made off . Wettability, the tendency for water or oil to spread over a surface, of the particle surfaces is one...... of the controlling factors for the effectiveness of water flooding, one of the most common methods to improve oil recovery in Chalk reservoirs. Understanding surface wetting and its variability at scales smaller than the pore dimension will potentially provide clues for more effective oil production methods. We used...

Quick, Easy, and Economic Mineralogical Studies of Flooded Chalk for EOR Experiments Using Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Laura Borromeo

2018-05-01

Full Text Available Understanding the chalk-fluid interactions and the associated mineralogical and mechanical alterations on a sub-micron scale are major goals in Enhanced Oil Recovery. Mechanical strength, porosity, and permeability of chalk are linked to mineral dissolution that occurs during brine injections, and affect the reservoir potential. This paper presents a novel “single grain” methodology to recognize the varieties of carbonates in rocks and loose sediments: Raman spectroscopy is a non-destructive, quick, and user-friendly technique representing a powerful tool to identify minerals down to 1 µm. An innovative working technique for oil exploration is proposed, as the mineralogy of micron-sized crystals grown in two flooded chalk samples (Liége, Belgium was successfully investigated by Raman spectroscopy. The drilled chalk cores were flooded with MgCl2 for ca. 1.5 (Long Term Test and 3 years (Ultra Long Term Test under North Sea reservoir conditions (Long Term Test: 130 °C, 1 PV/day, 9.3 MPa effective stress; Ultra Long Term Test: 130 °C, varying between 1–3 PV/day, 10.4 MPa effective stress. Raman spectroscopy was able to identify the presence of recrystallized magnesite along the core of the Long Term Test up to 4 cm from the injection surface, down to the crystal size of 1–2 µm. In the Ultra Long Term Test core, the growth of MgCO3 affected nearly the entire core (7 cm. In both samples, no dolomite or high-magnesium calcite secondary growth could be detected when analysing 557 and 90 Raman spectra on the Long and Ultra Long Term Test, respectively. This study can offer Raman spectroscopy as a breakthrough tool in petroleum exploration of unconventional reservoirs, due to its quickness, spatial resolution, and non-destructive acquisition of data. These characteristics would encourage its use coupled with electron microscopes and energy dispersive systems or even electron microprobe studies.

Reactive transport modelling of groundwater chemistry in a chalk aquifer at the watershed scale.

Science.gov (United States)

Mangeret, A; De Windt, L; Crançon, P

2012-09-01

This study investigates thermodynamics and kinetics of water-rock interactions in a carbonate aquifer at the watershed scale. A reactive transport model is applied to the unconfined chalk aquifer of the Champagne Mounts (France), by considering both the chalk matrix and the interconnected fracture network. Major element concentrations and main chemical parameters calculated in groundwater and their evolution along flow lines are in fair agreement with field data. A relative homogeneity of the aquifer baseline chemistry is rapidly reached in terms of pH, alkalinity and Ca concentration since calcite equilibrium is achieved over the first metres of the vadose zone. However, incongruent chalk dissolution slowly releases Ba, Mg and Sr in groundwater. Introducing dilution effect by rainwater infiltration and a local occurrence of dolomite improves the agreement between modelling and field data. The dissolution of illite and opal-CT, controlling K and SiO(2) concentrations in the model, can be approximately tackled by classical kinetic rate laws, but not the incongruent chalk dissolution. An apparent kinetic rate has therefore been fitted on field data by inverse modelling: 1.5×10(-5) mol(chalk)L (-1) water year (-1). Sensitivity analysis indicates that the CO(2) partial pressure of the unsaturated zone is a critical parameter for modelling the baseline chemistry over the whole chalk aquifer. Copyright © 2012 Elsevier B.V. All rights reserved.

Reactor safety research and development in Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Nitheanandan, T. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2014-07-01

Atomic Energy of Canada Limited's Chalk River Laboratories provides three different services to stakeholders and customers. The first service provided by the laboratory is the implementation of Research and Development (R&D) programs to provide the underlying technological basis of safe nuclear power reactor designs. A significant portion of the Canadian R&D capability in reactor safety resides at Atomic Energy of Canada Limited's Chalk River Laboratories, and this capability was instrumental in providing the science and technology required to aid in the safety design of CANDU power reactors. The second role of the laboratory has been in supporting nuclear facility licensees to ensure the continued safe operation of nuclear facilities, and to develop safety cases to justify continued operation. The licensing of plant life extension is a key industry objective, requiring extensive research on degradation mechanisms, such that safety cases are based on the original safety design data and valid and realistic assumptions regarding the effect of ageing and management of plant life. Recently, Chalk River Laboratories has been engaged in a third role in research to provide the technical basis and improved understanding for decision making by regulatory bodies. The state-of-the-art test facilities in Chalk River Laboratories have been contributing to the R&D needs of all three roles, not only in Canada but also in the international community, thorough Canada's participation in cooperative programs lead by International Atomic Energy Agency and the OECD's Nuclear Energy Agency. (author)

Province of Ontario nuclear emergency plan part V - Chalk River

International Nuclear Information System (INIS)

1991-10-01

The aim of Part 5 of the Provincial Nuclear Emergency Plan is to describe the measures that shall be undertaken to deal with a nuclear emergency caused by the Chalk River Laboratories. This plan deals mainly with actions at the Provincial level and shall by supplemented by the appropriate Municipal Plan. The Townships of Rolph, Buchanan, Wylie, and McKay, the Town of Deep River and the Village of Chalk River are the designated municipalities with respect to CRL. 2 tabs., 5 figs

Province of Ontario nuclear emergency plan part V - Chalk River

Energy Technology Data Exchange (ETDEWEB)

NONE

1991-10-01

The aim of Part 5 of the Provincial Nuclear Emergency Plan is to describe the measures that shall be undertaken to deal with a nuclear emergency caused by the Chalk River Laboratories. This plan deals mainly with actions at the Provincial level and shall by supplemented by the appropriate Municipal Plan. The Townships of Rolph, Buchanan, Wylie, and McKay, the Town of Deep River and the Village of Chalk River are the designated municipalities with respect to CRL. 2 tabs., 5 figs.

Elasticity and electrical resistivity of chalk and greensand during water flooding with selective ions

DEFF Research Database (Denmark)

Katika, Konstantina; Alam, Mohammad Monzurul; Alexeev, Artem

2018-01-01

is water-wet after flooding. Greensand remained mixed wet throughout the experiments. Electrical resistivity data are in agreement with this interpretation. The electrical resistivity data during flooding revealed that the formation brine is not fully replaced by the injected water in both chalk......Water flooding with selective ions has in some cases lead to increased oil recovery. We investigate the physical processes on a pore scale that are responsible for changes in petrophysical and mechanical properties of four oil-bearing chalk and four oil-bearing greensand samples caused by flooding...... with brines containing varying amounts of dissolved NaCl, Na2SO4, MgCl2 and MgSO4. Ultrasonic P-wave velocity and AC resistivity measurements were performed prior to, during and after flow through experiments in order to identify and quantify the processes related to water flooding with selective ions. Low...

Regional transport of radioxenon released from the Chalk River Laboratories medical isotope facility

International Nuclear Information System (INIS)

Christine Johnson; Steven Biegalski

2015-01-01

An examination of proposed sampling sites near Chalk River Laboratories in Ontario, Canada is performed by considering the regional transport of radioxenon using atmospheric dispersion modeling. The local geography is considered, as are the local meteorological conditions during the summer months. In particular the impacts of predicted conditions on the imprinting of atmospheric radioxenon into the subsurface are considered and weighed against site proximity, geography, and geology. (author)

Investigation of Lecturer's Chalk by x-ray Florescence and Fast Neutron Activation Techniques

International Nuclear Information System (INIS)

Hassan, M.F.

2011-01-01

Different samples of lecturer's chalk were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. The concentrations of the elements (Ca and small traces of Al, Fe, Mg and Si) were measured and their presence was confirmed by gamma-ray, lifetime and/or XRF measurements.

From ooze to sedimentary rock, the first diagenetic processes affecting the chalk of eastern Denmark

DEFF Research Database (Denmark)

Moreau, Julien; Boussaha, Myriam; Nielsen, Lars

processes operating in the chalk sediments at widely different scales into a single diagenetic model: At Stevns the chalk is affected by an extensive polygonal fault system which is expressed in onshore and offshore seismic profiles. Smaller scale contractional features like deformation bands (hairline...... strongly affect reservoir properties of the chalk both by establishing compartments and vertical connections. A better understanding of these reservoir modifications will be critical for improving the predictive capability of models describing the behaviour of drinking water and hydrocarbons hosted...

Agricultural diffuse pollution in a chalk aquifer (Trois Fontaines, France): Influence of pesticide properties and hydrodynamic constraints

Science.gov (United States)

Baran, N.; Lepiller, M.; Mouvet, C.

2008-08-01

SummaryThe characterization of the transfer of pesticides to and in groundwater is essential for effective water resource management. Intensive monitoring, from October 1989 to May 2006, of a weakly karstified chalk aquifer system in a 50 km 2 agricultural catchment, enabled the characterization of the temporal variability of pesticide concentrations in the groundwater of the main outlet. Atrazine and its metabolite deethylatrazine were quantified 394 and 393 times in 476 samples with concentrations ranging from the quantification limit (0.025 μg L -1) to 5.3 and 1.86 μg L -1, respectively. This common presence, compared to the rare detections of isoproturon (in 108 of 476 samples), the pesticide most widely used in the catchment during at least the past decade, highlighted the significant effect of pesticide properties in the time series of concentrations observed in the groundwater. The use of geochemical tracers (nitrate, chloride) analysed in the groundwater and the hydrodynamic monitoring of the system (discharge, water levels) enabled identification of various infiltration mechanisms governing the functioning of the system. The hydrodynamic study showing that the relative contribution of the infiltration mechanisms varies with time, made it possible to explain major variations observed in the pesticide-concentration time series recorded at the spring.

Radiocarbon dating with the Chalk River MP Tandem accelerator

International Nuclear Information System (INIS)

Ball, G.C.; Andrews, H.R.; Brown, R.M.; Burn, N.; Davies, W.G.; Imahori, Y.; Milton, J.C.D.

1981-01-01

During the past three years an automated radiocarbon dating system based on the MP Tandem accelerator has been developed for the analysis of 14 C in groundwater samples from the nuclear waste disposal research program and other small samples of scientific interest. At the present time 14 C/ 12 C ratio measurements can be determined with an accuracy of about 5% and the system background levels (approx. 35000 to 45000 years) are totally determined by sample and/or ion source contamination. Our goal has been to develop a dedicated reliable system for routine analysis that will produce accurate results with a minimum expenditure of human resources and accelerator beam time. Improvements required to operate the tandem accelerator as a quantitative tool have also benefited the rest of the experimental nuclear physics program. The early evolution of the dating facility was described previously. This paper is a brief report of the current status at Chalk River

The End of "Chalk and Talk"

Science.gov (United States)

Barlow, Tim

2012-01-01

"Chalk and talk" had been the staple pedagogical approach of my Science teaching practice since entering the profession. I felt that there was a great deal of information that I must impart to my students. My tried and tested way to deliver information to my students had always been simply to stand in front of them and tell it to them... So what…

The Effect of Bacteria Penetration on Chalk Permeability

DEFF Research Database (Denmark)

Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

Analysis of fine-dispersed chalk usage as mineral additive in the composition of sand aggrerate concrete

Directory of Open Access Journals (Sweden)

Светлана Николаевна Чепурная

2016-12-01

Full Text Available The research results of fine-disperse chalk addition on physical and mechanical properties of the cement stone and concrete are shown. It is determined that fine-disperse chalk addition in the binder composition increases the content of ultrafine particles. The chalk particles fill the pore space between the cement particles, increasing the packing density, which leads to a density increase, which consequently leads to improved physical and mechanical properties of the concrete: water tightness, cold resistance, corrosion resistance, crack resistance and other properties

Impedance imaging in core analysis. Imaging of phase distributions in samples of natural cores of North Sea chalk containing conducting as well as non-conducting fluids. Part: 1-3

Energy Technology Data Exchange (ETDEWEB)

Laursen, S. [DTU, Inst. for Kemi (Denmark)] Moeller Nielsen, C. [DTU, Inst. for Energiteknik (Denmark)

1997-12-31

The present report documents the efforts to develop an impedance method for determining the distribution of the water saturation in a chalk core sample. Measurement of this distribution during a displacement process will make it possible to make numerical simulations of the process which may in turn reveal important rock parameters. The impedance method is one among other methods to determine saturation profiles in a research programme on rock parameters with participants from Danmarks Tekniske Universitet, DTU, and Danmarks og Groenlands Geologiske Undersoegelse, GEUS. The other methods investigated are nmr-scanning and {gamma}-logging. (au)

Ultrasonic velocities of North Sea chalk samples: influence of porosity, fluid content and texture

DEFF Research Database (Denmark)

Rogen, B.; Fabricius, Ida Lykke; Japsen, P.

2005-01-01

a porosity-reducing effect and that samples rich in large grains have a relatively low porosity for a given P-wave modulus. The clay content in the samples is low and is mainly represented by either kaolinite or smectite; samples with smectite have a lower P-wave modulus than samples with kaolinite at equal...

A summary of the Chalk River valve packing evaluation program 1985 - 1990

International Nuclear Information System (INIS)

Aikin, J.A.; Doubt, G.L.; Lade, C.R.

1990-12-01

The move away from asbestos-based valve packing products has generated concern among valve manufacturers, packing manufacturers and user groups about the reliability and safety of non-asbestos based products for long-term use. AECL Research, Chalk River, has been actively evaluating these new valve packing products since 1985. This report describes the work done at Chalk River from 1985 to 1990. The report includes both Electric Power Research Institute (EPRI) and CANDU Owners Group (COG) funded studies. A description of the test programs and a brief summary of the functional performance of the more successful materials (die-formed graphite, braided asbestos and braided non-asbestos) on friction, stem leakage and consolidation are provided. At this time, Chalk River and Ontario Hydro have approved the following packing arrangements: for non-live-loaded valves, the recommended replacements packing for braided asbestos is combination flexible graphite packing sets; and, for heavy water valves originally designed with JC187I, the recommended replacement packing is approved braided-asbestos products

Nano sized clay detected on chalk particle surfaces

DEFF Research Database (Denmark)

Skovbjerg, Lone; Hassenkam, Tue; Makovicky, Emil

2012-01-01

that in calcite saturated water, both the polar and the nonpolar functional groups adhere to the nano sized clay particles but not to calcite. This is fundamentally important information for the development of conceptual and chemical models to explain wettability alterations in chalk reservoirs...

Diagenetic Variations between Upper Cretaceous Outcrop and Deeply Buried Reservoir Chalks of the North Sea Area

DEFF Research Database (Denmark)

Hjuler, Morten Leth; Fabricius, Ida Lykke

2007-01-01

-particle connections and less altered particle shapes. The non-carbonate mineralogy of outcrop chalks is dominated by quartz, occasionally opal-CT and clinoptilolite, and the clay mineral smectite. In offshore chalks quartz still dominates, opal-CT has recrystallized into submicron-size quartz crystals and smectite...

Chalk Catchment Transit Time: Unresolved Issues

Energy Technology Data Exchange (ETDEWEB)

Darling, W. G.; Gooddy, D. C. [British Geological Survey, Crowmarsh Gifford, Wallingford, Oxfordshire (United Kingdom); Barker, J. A. [School of Civil Engineering and the Environment, University of Southampton, Southampton (United Kingdom); Robinson, M. [Centre for Ecology and Hydrology, Crowmarsh Gifford, Wallingford, Oxfordshire (United Kingdom)

2013-07-15

The mean transit time (MTT) of a catchment is the average residence time of water from rainfall to river outflow at the foot of the catchment. As such, MTT has important water quality as well as resource implications. Many catchments worldwide have been measured for MTT using environmental isotopes, yet the Chalk, an important aquifer in NW Europe, has received little attention in this regard. The catchment of the River Lambourn in southern England has been intermittently studied since the 1960s using isotopic methods. A tritium peak measured in the river during the 1970s indicates an apparent MTT of {approx}15 years, but the thick unsaturated zone (average {approx}50 m) of the catchment suggests that the MTT should be much greater because of the average downward movement through the Chalk of {approx}1 m/a consistently indicated by tritium and other tracers. Recent work in the catchment using SF{sub 6} as a residence time indicator has given groundwater ages in the narrow range 11-18 yrs, apparently supporting the river tritium data but in conflict with the unsaturated zone data even allowing for a moderate proportion of rapid bypass flow. The MTT of the catchment remains unresolved for the time being. (author)

Seismic geomorphology and origin of diagenetic geobodies in the Upper Cretaceous Chalk of the North Sea Basin (Danish Central Graben)

DEFF Research Database (Denmark)

Smit, F. W. H.; van Buchem, F.S.P.; Holst, J.H.

2018-01-01

that the geobodies are of an open-system diagenetic origin caused by ascending basin fluids guided by faults and stratigraphic heterogeneities. Increased amounts of porosity-occluding cementation, contact cement and/or high-density/-velocity minerals caused an impedance contrast that can be mapped in seismic data...... failure, followed by local mechanical compaction of high-porous chalks, paired with 2) ascension of basinal diagenetic fluids along fault systems that locally triggered cementation of calcite and dolomite within the chalk, causing increased contact cements and/or reducing porosity. The migration pathway...... of the fluids is marked by the SCRs, which are the outlines of high-density bodies of chalk nested in highly porous chalks. This study thus provides new insights into the 3D relationship between fault systems, fluid migration and diagenesis in chalks, and has important applications for basin modeling...

Quantitative NMR measurements on core samples

International Nuclear Information System (INIS)

Olsen, Dan

1997-01-01

Within the frame of an EFP-95 project NMR methods for porosity determination in 2D, and for fluid saturation determination in 1D and 2D have been developed. The three methods have been developed and tested on cleaned core samples of chalk from the Danish North Sea. The main restriction for the use of the methods is the inherently short T2 relaxation constants of rock samples. Referring to measurements conducted at 200 MHz, the 2D porosity determination method is applicable to sample material with T2 relaxation constants down to 5 ms. The 1D fluid saturation determination method is applicable to sample material with T2 relaxation constants down to 3 ms, while the 2D fluid saturation determination method is applicable to material with T2 relaxation constants down to 8 ms. In the case of the 2D methods these constraints as a minimum enables work on the majority of chalk samples of Maastrichtian age. The 1D fluid saturation determination method in addition is applicable to at least some chalk samples of Danian and pre-Maastrichtian age. The spatial resolution of the 2D porosity determination method, the 1D fluid saturation methods, and the 2D fluid saturation method is respectively 0.8 mm, 0.8 mm and 2 mm. Reproducibility of pixel values is for all three methods 2%- points. (au)

Facilities for post-irradiation examination of experimental fuel elements at Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Mizzan, E.; Chenier, R.J.

1979-10-01

Expansion of post-irradiation facilities at the Chalk River Nuclear Laboratories and steady improvement in hot-cell techniques and equipment are providing more support to Canada's reactor fuel development program. The hot-cell facility primarily used for examination of experimental fuels averages a quarterly throughput of 40 elements and 110 metallographic specimens. New developments in ultrasonic testing, metallographic sample preparation, active storage, active waste filtration, and fissile accountability are coming into use to increase the efficiency and safety of hot-cell operations. (author)

Kolmanda aastatuhande piraadid / kommenteerinud Peter Chalk ja Gordan Van Hook

Index Scriptorium Estoniae

2009-01-01

Piraatlusest Somaalia piirkonnas ja rahvusvahelistest dokumentidest piraatluse vastu võitlemiseks 21. sajandil. Kommenteerivad uurimiskeskuse RAND Corporation vanempoliitanalüütik Peter Chalk ja transpordikompanii Maersk Line innovatsiooni ja arenduse vanemdirektor Gordan Van Hook

The transport and behaviour of isoproturon in unsaturated chalk cores

Science.gov (United States)

Besien, T. J.; Williams, R. J.; Johnson, A. C.

2000-04-01

A batch sorption study, a microcosm degradation study, and two separate column leaching studies were used to investigate the transport and fate of isoproturon in unsaturated chalk. The column leaching studies used undisturbed core material obtained from the field by dry percussion drilling. Each column leaching study used 25 cm long, 10 cm wide unsaturated chalk cores through which a pulse of isoproturon and bromide was eluted. The cores were set-up to simulate conditions in the unsaturated zone of the UK Chalk aquifer by applying a suction of 1 kPa (0.1 m H 2O) to the base of each column, and eluting at a rate corresponding to an average recharge rate through the unsaturated Chalk. A dye tracer indicated that the flow was through the matrix under these conditions. The results from the first column study showed high recovery rates for both isoproturon (73-92%) and bromide (93-96%), and that isoproturon was retarded by a factor of about 1.23 relative to bromide. In the second column study, two of the four columns were eluted with non-sterile groundwater in place of the sterile groundwater used on all other columns, and this study showed high recovery rates for bromide (85-92%) and lower recovery rates for isoproturon (66-79% — sterile groundwater, 48-61% — non-sterile groundwater). The enhanced degradation in the columns eluted with non-sterile groundwater indicated that groundwater microorganisms had increased the degradation rate within these columns. Overall, the reduced isoproturon recovery in the second column study was attributed to increased microbial degradation as a result of the longer study duration (162 vs. 105 days). The breakthrough curves (BTCs) for bromide had a characteristic convection-dispersion shape and were accurately simulated with the minimum of calibration using a simple convection-dispersion model (LEACHP). However, the isoproturon BTCs had an unusual shape and could not be accurately simulated.

Fault zone processes in mechanically layered mudrock and chalk

Science.gov (United States)

Ferrill, David A.; Evans, Mark A.; McGinnis, Ronald N.; Morris, Alan P.; Smart, Kevin J.; Wigginton, Sarah S.; Gulliver, Kirk D. H.; Lehrmann, Daniel; de Zoeten, Erich; Sickmann, Zach

2017-04-01

A 1.5 km long natural cliff outcrop of nearly horizontal Eagle Ford Formation in south Texas exposes northwest and southeast dipping normal faults with displacements of 0.01-7 m cutting mudrock, chalk, limestone, and volcanic ash. These faults provide analogs for both natural and hydraulically-induced deformation in the productive Eagle Ford Formation - a major unconventional oil and gas reservoir in south Texas, U.S.A. - and other mechanically layered hydrocarbon reservoirs. Fault dips are steep to vertical through chalk and limestone beds, and moderate through mudrock and clay-rich ash, resulting in refracted fault profiles. Steeply dipping fault segments contain rhombohedral calcite veins that cross the fault zone obliquely, parallel to shear segments in mudrock. The vertical dimensions of the calcite veins correspond to the thickness of offset competent beds with which they are contiguous, and the slip parallel dimension is proportional to fault displacement. Failure surface characteristics, including mixed tensile and shear segments, indicate hybrid failure in chalk and limestone, whereas shear failure predominates in mudrock and ash beds - these changes in failure mode contribute to variation in fault dip. Slip on the shear segments caused dilation of the steeper hybrid segments. Tabular sheets of calcite grew by repeated fault slip, dilation, and cementation. Fluid inclusion and stable isotope geochemistry analyses of fault zone cements indicate episodic reactivation at 1.4-4.2 km depths. The results of these analyses document a dramatic bed-scale lithologic control on fault zone architecture that is directly relevant to the development of porosity and permeability anisotropy along faults.

Trial coring in LLRW trenches at Chalk River

International Nuclear Information System (INIS)

Donders, R.E.; Killey, R.W.D.; Franklin, K.J.; Strobel, G.S.

1996-11-01

As part of a program to better characterize the low-hazard radioactive waste managed by AECL at Chalk River Laboratories, coring techniques in waste trenches are being assessed. Trial coring has demonstrated that sampling in waste regions is possible, and that boreholes can be placed through the waste trenches. Such coring provides a valuable information-gathering technique. Information available from trench coring includes: trench cover depth, waste region depth, waste compaction level, and detailed stratigraphic data; soil moisture content and facility drainage performance; borehole gamma logs that indicate radiation levels in the region of the borehole; biochemical conditions in the waste regions, vadose zone, and groundwater; site specific information relevant to contaminant migration modelling or remedial actions; information on contaminant releases and inventories. Boreholes through the trenches can also provide a means for early detection of potential contaminant releases. (author). 4 refs., 4 tabs., 4 figs

Initial field measurements on the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Ormrod, J.H.; Chan, K.C.; Hill, J.H.

1980-12-01

The midplane magnetic field of the Chalk River superconducting cyclotron has been mapped in detail over the full operating range of 2.5 to 5 tesla. The field measuring apparatus is described and results given include measurements of the field stability, reproducibility and harmonic content. (author)

Benthic macrofauna variations and community structure in Cenomanian cyclic chalk-marl from Southerham Grey Pit, SE England

DEFF Research Database (Denmark)

Lauridsen, Bodil Wesenberg; Gale, A. S.; Surlyk, Finn

2009-01-01

Cenomanian chalk-marl couplets from England represent the 20 ka Milankovitch precession cycle. Fossil communities from both chalk and marl are identified to test if the orbital fluctuations and the associated changes in substrate lithology and climate exerted any control on the benthic macrofauna...

Acidity of sphagnum and its relation to chalk and mineral salts

Energy Technology Data Exchange (ETDEWEB)

Skene, M

1915-01-01

In addition to the criticism and elucidation of various other points, the chief conclusions which may be drawn from the preceding pages are: (1) There is a variation in acidity and in sensitiveness to chalk between the different species of sphagnum. (2) There is a correlation between degree of acidity and degree of sensitiveness. (3) The connection between the two is indirect, not direct. (4) The sphagna thrive in acid solutions: the injurious effect of chalk, and of alkalies in general, is due to the substitution of an alkaline for an acid reaction. (5) Mineral solutions are generally physiologically harmless, but may be ecologically harmful. (6) The sphagna do actually utilize in growth bases held absorbed by the acid compounds of the cell-walls.

Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

DEFF Research Database (Denmark)

Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

2013-01-01

The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...... solutions of the same ionic strength. Saturation with a solution that contained divalent ions caused a major shift on the distribution of the relaxation time. The changes were probably due to precipitats forming extra internal surface in the sample. Sonic velocities were relatively low in the MgCl2 solution...

Process-based modelling to evaluate simulated groundwater levels and frequencies in a Chalk catchment in south-western England

Science.gov (United States)

Brenner, Simon; Coxon, Gemma; Howden, Nicholas J. K.; Freer, Jim; Hartmann, Andreas

2018-02-01

Chalk aquifers are an important source of drinking water in the UK. Due to their properties, they are particularly vulnerable to groundwater-related hazards like floods and droughts. Understanding and predicting groundwater levels is therefore important for effective and safe water management. Chalk is known for its high porosity and, due to its dissolvability, exposed to karstification and strong subsurface heterogeneity. To cope with the karstic heterogeneity and limited data availability, specialised modelling approaches are required that balance model complexity and data availability. In this study, we present a novel approach to evaluate simulated groundwater level frequencies derived from a semi-distributed karst model that represents subsurface heterogeneity by distribution functions. Simulated groundwater storages are transferred into groundwater levels using evidence from different observations wells. Using a percentile approach we can assess the number of days exceeding or falling below selected groundwater level percentiles. Firstly, we evaluate the performance of the model when simulating groundwater level time series using a spilt sample test and parameter identifiability analysis. Secondly, we apply a split sample test to the simulated groundwater level percentiles to explore the performance in predicting groundwater level exceedances. We show that the model provides robust simulations of discharge and groundwater levels at three observation wells at a test site in a chalk-dominated catchment in south-western England. The second split sample test also indicates that the percentile approach is able to reliably predict groundwater level exceedances across all considered timescales up to their 75th percentile. However, when looking at the 90th percentile, it only provides acceptable predictions for long time periods and it fails when the 95th percentile of groundwater exceedance levels is considered. By modifying the historic forcings of our model

Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

Energy Technology Data Exchange (ETDEWEB)

Phillips, W.S.; Rutledge, J.T.; Gardner, T.L. [SPE, Richardson, TX (United States); Fairbanks, T.D.; Miller, M.E.; Schuessler, B.K. [Los Alamos National Lab., NM (United States)

1996-11-01

Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

Effect of fluid-solid friction on the stiffness of chalk

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Nguh Akam, Hosea; Fabricius, Ida Lykke

2011-01-01

Chalks behave weaker at water saturated condition. We studied this softening effect as a function of Biot’s frequency ratio, which is a ratio between measured ultrasonic wave frequency and Biot critical frequency, fc. Kinematic viscosity of fluid and permeability of rock determines fc. We observe...

Vertical distribution of radioactive particles in Ottawa River sediment near the Chalk River Laboratories

International Nuclear Information System (INIS)

Lee, D.R.; Hartwig, D.S.

2011-01-01

Previously, we described an area of above-background levels of radioactivity in the bed of the Ottawa River near the Chalk River Laboratories. The area was about 200 m wide by 400 m long and in water 8 to 30 m deep. The source of the radioactivity was associated with the location of cooling-water discharge. Particles of radioactive material were later recovered from the upper 10-15 cm of sediment and were determined to be sand-sized grains of nuclear fuel and corrosion products. This report provides an examination of the vertical distribution of radioactive particles in the riverbed. Twenty-three dredge samples (representing 1.2 m 2 of riverbed) were collected near the Process Outfall. Each dredge sample was dissected in horizontal intervals 1-cm-thick. Each interval provided a 524 cm 3 sample of sediment that was carefully examined for particulate radioactivity. Approximately 80% of the radioactivity appeared to be associated with discrete particles. Although the natural sediment in the general area is cohesive, silty clay and contains less than 10% sand, the sediment near the Outfall was found to be rich in natural sand, presumably from sources such as winter sanding of roads at the laboratories. The radioactive particles were almost entirely contained in the top-most 10 cm of the river bed. The majority of the particles were found several centimetres beneath the sediment surface and the numbers of particles and the radioactivity of the particles peaked 3 to 7 cm below the sediment surface. Based on the sediment profile, there appeared to have been a marked decrease in the deposition of particulate radioactivity in recent decades. The vertical distribution of radioactive particles indicated that sedimentation is resulting in burial and that the deposition of most of the particulate radioactivity coincided with the operation of Chalk River's NRX reactor from 1947 to 1992. (author)

Capillary fringe and tritium and nitrogen tracing history in the Senonian chalk of Champagne

International Nuclear Information System (INIS)

Ballif, J.L.

1998-01-01

In the middle of Champagne-Ardenne area, a chalky zone is located, directly on top of which lies the soil and in which the water table is relatively close the soil; which allows for capillary direction to the surface horizons and the renewal of water reserve. After the presentation of the hydrological characteristics, the total porosity of chalk, the pores distribution, the capillary attraction is shown by the hydrological comportment of the soil and the upper part of the unsaturated zone of chalk. In the homogeneous rock, the tritium and nitrogen transfers reveal the historical tracks. (authors)

Waveform analysis of crosshole GPR data collected in heterogeneous chalk deposits

DEFF Research Database (Denmark)

Keskinen, Johanna; Nielsen, Lars; Zibar, Majken Caroline Looms

2014-01-01

Chalks are important reservoirs for groundwater production onshore Denmark and for hydrocarbons in the North Sea Basin. Therefore this rock type is studied extensively with geological and geophysical methods. Ground-penetrating radar (GPR) tomography is used to characterize fine-scale reservoir...

Geologic feasibility of selected chalk-bearing sequences within the conterminous United States with regard to siting of radioactive-waste repositories

International Nuclear Information System (INIS)

Gonzales, S.

1975-11-01

Various geologic and hydrologic parameters are evaluated in relation to assessing the potential for repository storage of high-level radioactive wastes within several stratigraphic sequences dominated by chalks and chalky limestones. The former lithology is defined as a carbonate rock consisting mainly of very fine-grained particles of micritic calcite. Although chalks also contain coarser-grained particles such as shells of fossil foraminifera and non-calcitic minerals like quartz, most contain more than 90 percent micritic material. The latter represents broken fossil coccolith plates. The chalk-dominated formations discussed are exposed and underlie two different physiographic provinces which nevertheless display a general similarity in both being regions of extensive plains. The Niobrara Formation occurs mainly within the Great Plains province, while the Austin Chalk of Texas and the Selma Group of Alabama and Mississippi are located in the western and eastern Gulf Coastal Plain, respectively. The preliminary assessment is that chalk-bearing sequences show some promise and are deserving of added consideration and evaluation. Containment for hundreds of thousands of years would seem possible given certain assumptions. The most promising units from the three studied are the Niobrara Formation and Selma Group. Regional and local conditions make the Austin more suspect

Electroosmotic dewatering of chalk sludge, iron hydroxide sludge, wet fly ash and biomass

Energy Technology Data Exchange (ETDEWEB)

Hansen, H.K.; Kristensen, I.V.; Ottosen, L.M.; Villumsen, A. [Dept. of Geology and Geotechnical Engineering, The Technical Univ. of Denmark, Lyngby (Denmark)

2001-07-01

Electroosmotic dewatering has been tested in laboratory cells for 4 different porous materials: chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge from enzyme production. In all cases it was possible to remove water when passing electric DC current through the material. Casagrande's coefficients for the three materials where determined at different water contents. In the electroosmotic experiments shown in this work chalk can be dewatered from 40% to 79% DM (dry matter), fly ash from 75 to 82% DM, iron hydroxide sludge from 2.7 to 19% DM and biomass from 3 to 33% DM. The process was not optimised indicating that higher dry matter contents could be achieved. (orig.)

The effect of divalent ions on the elasticity and pore collapse of chalk evaluated from compressional wave velocity and low-field Nuclear Magnetic Resonance (NMR)

DEFF Research Database (Denmark)

Katika, Konstantina; Addassi, Mouadh; Alam, Mohammad Monzurul

2015-01-01

The effects of divalent ions on the elasticity and the pore collapse of chalk were studied through rock-mechanical testing and low-field Nuclear Magnetic Resonance (NMR) measurements. Chalk samples saturated with deionized water and brines containing sodium, magnesium, calcium and sulfate ions were...... subjected to petrophysical experiments, rock mechanical testing and low-field NMR spectroscopy. Petrophysical characterization involving ultrasonic elastic wave velocities in unconfined conditions, porosity and permeability measurements, specific surface and carbonate content determination and backscatter...... electron microscopy of the materials were conducted prior to the experiments. The iso-frame model was used to predict the bulk moduli in dry and saturated conditions from the compressional modulus of water-saturated rocks. The effective stress coefficient, as introduced by Biot, was also determined from...

Groundwater conversion areas in chalk in the southern Frankish Alps

International Nuclear Information System (INIS)

Pfaff, T.

1987-01-01

In order to collect hydro-geological data, chalk water marking was done and/or interpreted, water balances were produced, the contents tritium, oxygen 18, calcium, magnesium and the groundwater temperatures and electrolytic conductivity of the groundwater were examined and the dry weather drainage of individual sources was analysed. (orig./PW) [de

High resolution microgravity investigations for the detection and characterisation of subsidence associated with abandoned, coal, chalk and salt mines

Energy Technology Data Exchange (ETDEWEB)

Styles, P.; Toon, S.; Branston, M.; England, R. [Keele Univ., Applied And Environmental Geophysics Group, School of Physical and Geographical Sciences (United Kingdom); Thomas, E.; Mcgrath, R. [Geotechnology, Neath (United Kingdom)

2005-07-01

The closure and decay of industrial activity involving mining has scarred the landscape of urban areas and geo-hazards posed by subsurface cavities are ubiquitous throughout Europe. Features of concern consist of natural solution cavities (e.g. swallow holes and sinkholes in limestone gypsum and chalk) and man-made cavities (mine workings, shafts) in a great variety of post mining environments, including coal, salt, gypsum, anhydrite, tin and chalk. These problems restrict land utilisation, hinder regeneration, pose a threat to life, seriously damage property and services and blight property values. This paper outlines the application of microgravity techniques to characterise abandoned mining hazard in case studies from Coal, Chalk and Salt Mining environments in the UK. (authors)

High resolution microgravity investigations for the detection and characterisation of subsidence associated with abandoned, coal, chalk and salt mines

International Nuclear Information System (INIS)

Styles, P.; Toon, S.; Branston, M.; England, R.; Thomas, E.; Mcgrath, R.

2005-01-01

The closure and decay of industrial activity involving mining has scarred the landscape of urban areas and geo-hazards posed by subsurface cavities are ubiquitous throughout Europe. Features of concern consist of natural solution cavities (e.g. swallow holes and sinkholes in limestone gypsum and chalk) and man-made cavities (mine workings, shafts) in a great variety of post mining environments, including coal, salt, gypsum, anhydrite, tin and chalk. These problems restrict land utilisation, hinder regeneration, pose a threat to life, seriously damage property and services and blight property values. This paper outlines the application of microgravity techniques to characterise abandoned mining hazard in case studies from Coal, Chalk and Salt Mining environments in the UK. (authors)

Controls on Cementation in a Chalk Reservoir

DEFF Research Database (Denmark)

Meireles, Leonardo Teixeira Pinto; Hussein, A.; Welch, M.J.

In this study, we identify different controls on cementation in a chalk reservoir. Biot’s coefficient, a measure of cementation, stiffness and strength in porous rocks, is calculated from logging data (bulk density and sonic Pwave velocity). We show that Biot’s coefficient is correlated...... to the water saturation of the Kraka reservoir and is partly controlled by its stratigraphic sub-units. While the direct causal relationship between Biot’s coefficient and water saturation cannot be extended for Biot’s coefficient and porosity, a correlation is also identified between the two, implying...

Groundwater recharge dynamics in unsaturated fractured chalk: a case study

Science.gov (United States)

Cherubini, Claudia; Pastore, Nicola; Giasi, Concetta I.; Allegretti, Nicolaetta M.

2016-04-01

The heterogeneity of the unsaturated zone controls its hydraulic response to rainfall and the extent to which pollutants are delayed or attenuated before reaching groundwater. It plays therefore a very important role in the recharge of aquifers and the transfer of pollutants because of the presence of temporary storage zones and preferential flows. A better knowledge of the physical processes in the unsaturated zone would allow an improved assessment of the natural recharge in a heterogeneous aquifer and of its vulnerability to surface-applied pollution. The case study regards the role of the thick unsaturated zone of the Cretaceous chalk aquifer in Picardy (North of France) that controls the hydraulic response to rainfall. In the North Paris Basin, much of the recharge must pass through a regional chalk bed that is composed of a porous matrix with embedded fractures. Different types of conceptual models have been formulated to explain infiltration and recharge processes in the unsaturated fractured rock. The present study analyses the episodic recharge in fractured Chalk aquifer using the kinematic diffusion theory to predict water table fluctuation in response to rainfall. From an analysis of the data, there is the evidence of 1) a seasonal behavior characterized by a constant increase in the water level during the winter/spring period and a recession period, 2) a series of episodic behaviors during the summer/autumn. Kinematic diffusion models are useful for predict preferential fluxes and dynamic conditions. The presented approach conceptualizes the unsaturated flow as a combination of 1) diffusive flow refers to the idealized portion of the pore space of the medium within the flow rate is driven essentially by local gradient of potential; 2) preferential flow by which water moves across macroscopic distances through conduits of macropore length.

Full-waveform inversion of cross-hole GPR data collected in a strongly heterogeneous chalk reservoir analogue with sharp permittivity and conductivity contrasts

DEFF Research Database (Denmark)

Keskinen, Johanna; Zibar, Majken Caroline Looms; Moreau, Julien

2014-01-01

Chalk sediments form an important reservoir for groundwater onshore and for hydrocarbons in the Danish sector of the North Sea. Cross-hole Ground-penetrating radar (GPR) tomography is an efficient method to investigate subtle porosity variations in the chalk. Traditional ray-based inversion...

Tracking selenium in the Chalk aquifer of northern France: Sr isotope constraints

International Nuclear Information System (INIS)

Cary, L.; Benabderraziq, H.; Elkhattabi, J.; Gourcy, L.; Parmentier, M.; Picot, J.; Khaska, M.; Laurent, A.; Négrel, Ph.

2014-01-01

Highlights: • We report the chemistry of the Chalk groundwater affected by Se contamination. • Strontium isotopes were used to identify the groundwater bodies and their mixings. • The spatial and temporal Se variability is mainly linked to the presence of Se-rich clays. • Saturation or desaturation of Se-rich clays control Se mobility. - Abstract: Groundwater at the southern and eastern edges of France’s Paris Basin has a selenium content that at times exceeds the European Framework Directive’s drinking-water limit value of 10 μg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr and Se/Sr ratios constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest Sr isotopic signature (0.70842) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest Sr isotopic signature (0.70789) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 μg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio (0.70826), and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se

Full-waveform Inversion of Crosshole GPR Data Collected in Strongly Heterogeneous Chalk

DEFF Research Database (Denmark)

Keskinen, Johanna; Zibar, Majken Caroline Looms; Nielsen, Lars

2015-01-01

Chalk is an important reservoir rock for hydrocarbons and for groundwater resources for many major cities. Therefore, this rock type has been extensively investigated using both geological and geophysical methods. Many applications of crosshole GPR tomography rely on the ray approximation...... and corresponding inversions of first break traveltimes and/or maximum first-cycle amplitudes. Due to the inherent limitations associated with such approaches, the resulting models tend to be overly smooth and cannot adequately capture the small-scale heterogeneities. In contrast, the full-waveform inversion uses...... address the importance of (i) adequate starting models, both in terms of the dielectric permittivity and the electrical conductivity, (ii) the estimation of the source wavelet, (iii) and the effects of data sampling density when imaging this rock type. Moreover, we discuss the resolution of the bedding...

Mortality among long-term Chalk River employees

International Nuclear Information System (INIS)

Werner, M.M.; Myers, D.K.

1986-12-01

Mortality among Chalk River Nuclear Laboratory (CRNL) employees who died during employment or after retirement has been updated to 1985 December 31. Data in tabular form are presented for overall mortality for male and female employees, for the participants in the clean-up for the NRX and NRU reactor accidents and for a group of CRNL staff with lifetime accumulative doses in excess of 0.2 Sv. Data are also presented on the different types of cancer causing death among male employees. No statistically significant increases in cancer deaths were found in any of the groups analyzed. 25 refs

Strength and Biot's coefficient for high-porosity oil- or water-saturated chalk

DEFF Research Database (Denmark)

Andreassen, Katrine Alling

. The Biot coefficient states the degree of cementation or how the pore pressure contributes to the strain resulting from an external load for a porous material. It is here calculated from dynamic measurements and correlated with the strength of outcrop chalk characterized by the onset of pore collapse...... during hydrostatic loading. The hypothesis is that the Biot coefficient and the theory of poroelasticity may cover the fluid effect by including the increased fluid bulk modulus from oil to water. A high number of test results for both oil- and water-saturated high-porosity outcrop chalk show correlation......In the petroleum industry it is relevant to know the Biot coefficient for establishing the effective stresses present in both the overburden and for the reservoir interval. When depleting a reservoir it is important to estimate the settlement through the strain imposed by the effective stress. Also...

Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea

Directory of Open Access Journals (Sweden)

Finn Surlyk

2011-12-01

Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

Experimental Study of Bacterial Penetration into Chalk Rock: Mechanisms and Effect on Permeability

DEFF Research Database (Denmark)

Halim, Amalia Yunita; Shapiro, Alexander; Eliasson Lantz, Anna

2014-01-01

Bacterial selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery, as bacteria can plug the water-swept zones of a reservoir, thus altering the flow paths and improving sweep efficiency. However, complete understanding of the penetration...... behavior of bacteria is lacking, especially in chalk formations where characteristic pore throat sizes are comparable with the sizes of bacterial cells. In this study, two bacterial strains, Bacillus licheniformis 421 (spore-forming) and Pseudomonas putida K12 (non-spore forming) were used to investigate...... the penetration of bacteria into chalk and its effect on permeability reduction. The core plugs were produced from Stevns Klint outcrop with low permeability (2–4 mD) and with pore sizes comparable to bacterial sizes. Both types of bacteria were able to penetrate and to be transported through the cores to some...

ACE - an algebraic compiler and encoder for the Chalk River datatron computer

International Nuclear Information System (INIS)

Kennedy, J.M.; Okazaki, E.A.; Millican, M.

1960-03-01

ACE is a program written for the Chalk River Datatron (Burroughs 205) Computer to enable the machine to compile a program for solving a problem from instructions supplied by the user in a notation related much more closely to algebra than to the machine's own code. (author)

WIMS-CRNL: A user's manual for the Chalk River version of WIMS

International Nuclear Information System (INIS)

Donnelly, J.V.

1986-01-01

This report describes the preparation of the input for WIMS-CRNL, the Chalk River version of the WIMS lattice code. Also included are notes on the operation of the code, contents of the associated libraries, and the relation of WIMS-CRNL to other versions of the code

Heating- and growing-degree days at Chalk River Nuclear Laboratories, 1976-1980

International Nuclear Information System (INIS)

Jay, P.C.; Wildsmith, D.P.

1981-05-01

An update of the report, Heating- and Growing-Degree-Days at Chalk River Nuclear Laboratories (AECL-5547) is presented along with various other meteorological variables which were not included in the previous publication. Also included, and shown in graph form, are the monthly degree-day frequencies. (author)

Geologic models and evaluation of undiscovered conventional and continuous oil and gas resources: Upper Cretaceous Austin Chalk

Science.gov (United States)

Pearson, Krystal

2012-01-01

The Upper Cretaceous Austin Chalk forms a low-permeability, onshore Gulf of Mexico reservoir that produces oil and gas from major fractures oriented parallel to the underlying Lower Cretaceous shelf edge. Horizontal drilling links these fracture systems to create an interconnected network that drains the reservoir. Field and well locations along the production trend are controlled by fracture networks. Highly fractured chalk is present along both regional and local fault zones. Fractures are also genetically linked to movement of the underlying Jurassic Louann Salt with tensile fractures forming downdip of salt-related structures creating the most effective reservoirs. Undiscovered accumulations should also be associated with structure-controlled fracture systems because much of the Austin that overlies the Lower Cretaceous shelf edge remains unexplored. The Upper Cretaceous Eagle Ford Shale is the primary source rock for Austin Chalk hydrocarbons. This transgressive marine shale varies in thickness and lithology across the study area and contains both oil- and gas-prone kerogen. The Eagle Ford began generating oil and gas in the early Miocene, and vertical migration through fractures was sufficient to charge the Austin reservoirs.

Controls on Cementation in a Chalk Reservoir

DEFF Research Database (Denmark)

Meireles, Leonardo Teixeira Pinto; Hussein, A.; Welch, M.J.

2017-01-01

In this study, we identify different controls on cementation in a chalk reservoir. Biot’s coefficient, a measure of cementation, stiffness and strength in porous rocks, is calculated from logging data (bulk density and sonic Pwave velocity). We show that Biot’s coefficient is correlated...... that some degree of pore filling cementation occurred in Kraka (Alam, 2010). Lack of correlation between Biot’s coefficient and Gamma Ray (GR) indicates that the small amount of clay present is generally located in the pore space, thus not contributing to frame stiffness. While there was no compositional...... control on cementation via clay, we could infer that stratigraphy impacts on the diagenetic process....

Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Final report, March 1996--September 1998

Energy Technology Data Exchange (ETDEWEB)

Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.; Groshong, R.H.; Jin, G.

1998-12-01

This project was designed to analyze the structure of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas to suggest ways in which oil recovery can be improved. The Eutaw Formation comprises 7 major flow units and is dominated by low-resistivity, low-contrast play that is difficult to characterize quantitatively. Selma chalk produces strictly from fault-related fractures that were mineralized as warm fluid migrated from deep sources. Resistivity, dipmeter, and fracture identification logs corroborate that deformation is concentrated in the hanging-wall drag zones. New area balancing techniques were developed to characterize growth strata and confirm that strain is concentrated in hanging-wall drag zones. Curvature analysis indicates that the faults contain numerous fault bends that influence fracture distribution. Eutaw oil is produced strictly from footwall uplifts, whereas Selma oil is produced from fault-related fractures. Clay smear and mineralization may be significant trapping mechanisms in the Eutaw Formation. The critical seal for Selma reservoirs, by contrast, is where Tertiary clay in the hanging wall is juxtaposed with poorly fractured Selma chalk in the footwall. Gilbertown Field can be revitalized by infill drilling and recompletion of existing wells. Directional drilling may be a viable technique for recovering untapped oil from Selma chalk. Revitalization is now underway, and the first new production wells since 1985 are being drilled in the western part of the field.

Stylolites, porosity, depositional texture, and silicates in chalk facies sediments:Ontong Java Plateau - Gorm and Tyra fields, North Sea

OpenAIRE

Fabricius, Ida Lykke; Borre, Mai K.

2007-01-01

Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperatu...

Reactor loops at Chalk River

International Nuclear Information System (INIS)

Sochaski, R.O.

1962-07-01

This report describes broadly the nine in-reactor loops, and their components, located in and around the NRX and NRU reactors at Chalk River. First an introduction and general description is given of the loops and their function, supplemented with a table outlining some loop specifications and nine simplified flow sheets, one for each individual loop. The report then proceeds to classify each loop into two categories, the 'main loop circuit' and the 'auxiliary circuit', and descriptions are given of each circuit's components in turn. These components, in part, are comprised of the main loop pumps, the test section, loop heaters, loop coolers, delayed-neutron monitors, surge tank, Dowtherm coolers, loop piping. Here again photographs, drawings and tables are included to provide a clearer understanding of the descriptive literature and to include, in tables, some specifications of the more important components in each loop. (author)

Environmental isotope studies related to groundwater flow and saline encroachment in the chalk aquifer of Lincolnshire, England

International Nuclear Information System (INIS)

Lloyd, J.W.; Howard, K.W.F.

1978-01-01

The isotopes of tritium and carbon are used to study part of the North Lincolnshire Chalk aquifer in England. The tritium data support the view that the aquifer is a thin fissure system and indicate that some changes in flow direction have occurred due to recent abstraction. The data are also consistent with other chemical data in elucidating groundwater entering the Chalk from deeper aquifers. Carbon isotopes are used to distinguish between saline water bodies and suggest that saline water was entrapped within the aquifer in the Eemian and Flandrian stages of the Pleistocene. (orig.) [de

Experimental study and mechanical modelling of the effects of water-driving in an oil saturated chalk. Application to the petroleum industry; Etude experimentale et modelisation mecanique des effets du balayage a l'eau dans une craie saturee d'huile. Application a l'industrie petroliere

Energy Technology Data Exchange (ETDEWEB)

Mata, C.

2001-01-01

The production of hydrocarbons may sometimes lead to compaction of the oil-reservoir layers with substantial collapse of the soil surface; this mechanism is usually mentioned as Subsidence. Classical remedy to this problem is to sustain the fluid pressure with the help of water injection. However, in presence of high porosity chalk (porosity > 30%), this technique does not give effective results: the subsidence rate at North Sea reservoirs (Ekofisk field), after injection, has remained unchanged. Some justify the subsistence in the chalk as caused by phenomena of dissolution of the carbonates; others think it is connected to the destruction of capillary menisci. In this research, we follow this second approach. This study is finalized to a better understanding of the compaction mechanisms in pure carbonates when water is injected. This is done by proposing -in micro-scale first and in macro-scale after- a physical model that agrees with empirical observations. In order to meet this target, IFP skills and experience in physical and chemical measurements (taken before, after and during mechanical tests) have proficiently joined ENPC laboratory (CERMMO) knowledge of micro and macro modelling. The soft rock studied is a Paris basin's white chalk (Craie de Guerville). Its physical and chemical characterisation (i.e.: silica content, porosity, permeability) is very similar to North Sea chalk, but Guerville chalk has never been in contact with oil and generally it crops out of the ground surface. Strength parameters of this rock have been first determined by standard triaxial tests. Three different saturation configurations have been examined: dry, fully oil-saturated and fully water-saturated. As literature clearly state, dry chalk is stronger than oil saturated chalk and the first two are largely stronger than water saturated chalk. Therefore uniaxial strain water injection tests have been performed on oil saturated samples. Results, coupled with previous physical

Investigated Miscible CO2 Flooding for Enhancing Oil Recovery in Wettability Altered Chalk and Sandstone Rocks

Energy Technology Data Exchange (ETDEWEB)

Tabrizy, Vahid Alipour

2012-07-01

The thesis addresses oil recovery by miscible CO2 flooding from modified sandstone and chalk rocks. Calcite mineral surface is modified with stearic acid (SA) and asphaltene, and the silicate mineral surfaces are modified with N,N-dimethyldodecylamine (NN-DMDA) and asphaltene. The stability of adsorbed polar components in presence of SO4 2- and Mg2 + ions is also investigated. Recovery from sandstone cores is consistently lower than that from chalk cores saturated with the same oil and flooded with CO2 at all miscible flooding conditions. This may be due to the larger permeability contrasts in sandstone cores, which promote the fingering phenomenon. Miscible CO2 flooding for chalk and sandstone cores with distilled water, as initial water saturation, shows also lower oil recovery than cores saturated with different ions. At higher miscible flooding conditions, higher oil recovery is obtained. However, presence of light components (such as C1 or C3) in oil reduced the recovery. Oil recovery in presence of methane (C1) is lower than that in presence of methane and propane (C1/C3). A ternary diagram was constructed in order to understand the CO2 flooding mechanism(s) at the different flooding conditions and in presence of light components. The side effect of the flooding with CO2 is the probability for asphaltene deposition. An approach based on solubility parameter in the liquid, is used to assess the risk for asphaltene deposition during CO2 miscible flooding. The light components (C1/C3) and higher flooding conditions enhanced the risk for asphaltene instability. It is also shown higher amount of asphaltene deposition in chalk cores than that in sandstone cores at similar miscibility conditions.(au)

Source and persistence of pesticides in a semi-confined chalk aquifer of southeast England

International Nuclear Information System (INIS)

Lapworth, D.J.; Gooddy, D.C.

2006-01-01

Pesticide contamination in groundwater is an increasing problem that poses a significant long-term threat to water quality. Following the detection of elevated concentrations of diuron in boreholes in a semi-confined chalk aquifer from southeast England, a sampling programme was undertaken. Between 2003 and 2004 diuron was observed in 90% of groundwaters analysed. In 60% of groundwater samples metabolites of diuron were more prevalent than the parent compound. Longer-term (1989-2005) monitoring shows that pollution of the aquifer by atrazine, simazine, and more recently diuron, shows a positive correlation with periods of high groundwater levels. Results from groundwater residence time indicators suggest that the highest diuron concentrations are associated with waters containing the greatest proportion of recent recharge. There is some evidence to indicate that diuron occurrence can be spatially related to areas of urban and industrial development and is probably correlated with amenity usage. - Pesticides and their metabolites from amenity use pose a long-term threat to groundwater quality

Source and persistence of pesticides in a semi-confined chalk aquifer of southeast England

Energy Technology Data Exchange (ETDEWEB)

Lapworth, D.J. [British Geological Survey, Maclean Building, Wallingford, Oxon OX10 8BB (United Kingdom); Gooddy, D.C. [British Geological Survey, Maclean Building, Wallingford, Oxon OX10 8BB (United Kingdom)]. E-mail: dcg@bgs.ac.uk

2006-12-15

Pesticide contamination in groundwater is an increasing problem that poses a significant long-term threat to water quality. Following the detection of elevated concentrations of diuron in boreholes in a semi-confined chalk aquifer from southeast England, a sampling programme was undertaken. Between 2003 and 2004 diuron was observed in 90% of groundwaters analysed. In 60% of groundwater samples metabolites of diuron were more prevalent than the parent compound. Longer-term (1989-2005) monitoring shows that pollution of the aquifer by atrazine, simazine, and more recently diuron, shows a positive correlation with periods of high groundwater levels. Results from groundwater residence time indicators suggest that the highest diuron concentrations are associated with waters containing the greatest proportion of recent recharge. There is some evidence to indicate that diuron occurrence can be spatially related to areas of urban and industrial development and is probably correlated with amenity usage. - Pesticides and their metabolites from amenity use pose a long-term threat to groundwater quality.

Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea: Plate 1

Directory of Open Access Journals (Sweden)

Surlyk, Finn

2011-12-01

Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

Edibility of sport fishes in the Ottawa River near Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Lee, D.R.; Chaput, T.; Miller, A.; Wills, C.A., E-mail: leed@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2013-12-15

To address the question of edibility of fish in the Ottawa River near Chalk River Laboratories (CRL), 123 game fish were collected for analysis from four locations: Mackey and Rolphton (45 km and 35 km upstream of Chalk River Laboratories (CRL), respectively), the Sandspit (Pointe au Bapteme) and Cotnam Island (1.6 km and 45 km downstream of CRL, respectively). Twenty-six to thirty-six game fish were collected at each location in 2007 and samples of flesh or bone were analyzed. Trap nets were used to collect only the fish required, allowing release of management-sensitive species. The focus was on walleye (Sander vitreus) because they are abundant and popular among anglers. A few northern pike (Esox lucius) and a smaller number of smallmouth bass (Micropterus dolomieui) were also collected at three of the four sites. Samples of the fish were analyzed for cesium-137 ({sup 137}Cs), strontium-90 ({sup 90}Sr), mercury (Hg), and selected organo-chlorine compounds. Concentrations of {sup 137}Cs in the flesh and {sup 90}Sr in the bones of sport fish were low and similar at all four locations and appear to reflect the global residuals from nuclear weapons testing (primarily in the 1960's) as opposed to releases from CRL. Possible explanations are: 1) Reductions in radionuclide releases from CRL in recent decades and 2) Relatively large foraging ranges of sport fish. Mercury concentrations were elevated in fishes in the Ottawa River and were significantly higher at the Sandspit and Rolphton than at Mackey and Cotnam Island (p<0.001). Mercury concentrations from the four sites are comparable to concentrations in other Ontario and Quebec lakes. It is advisable therefore, that consumers follow the fish consumption guidelines issued by provincial authorities when eating fish from the Ottawa River. Organo-chlorine compounds were not detected in walleye; however, they were detected in all eight of the pike collected at Cotnam Island. The highest organo

Edibility of sport fishes in the Ottawa River near Chalk River Laboratories

International Nuclear Information System (INIS)

Lee, D.R.; Chaput, T.; Miller, A.; Wills, C.A.

2013-01-01

To address the question of edibility of fish in the Ottawa River near Chalk River Laboratories (CRL), 123 game fish were collected for analysis from four locations: Mackey and Rolphton (45 km and 35 km upstream of Chalk River Laboratories (CRL), respectively), the Sandspit (Pointe au Bapteme) and Cotnam Island (1.6 km and 45 km downstream of CRL, respectively). Twenty-six to thirty-six game fish were collected at each location in 2007 and samples of flesh or bone were analyzed. Trap nets were used to collect only the fish required, allowing release of management-sensitive species. The focus was on walleye (Sander vitreus) because they are abundant and popular among anglers. A few northern pike (Esox lucius) and a smaller number of smallmouth bass (Micropterus dolomieui) were also collected at three of the four sites. Samples of the fish were analyzed for cesium-137 ( 137 Cs), strontium-90 ( 90 Sr), mercury (Hg), and selected organo-chlorine compounds. Concentrations of 137 Cs in the flesh and 90 Sr in the bones of sport fish were low and similar at all four locations and appear to reflect the global residuals from nuclear weapons testing (primarily in the 1960's) as opposed to releases from CRL. Possible explanations are: 1) Reductions in radionuclide releases from CRL in recent decades and 2) Relatively large foraging ranges of sport fish. Mercury concentrations were elevated in fishes in the Ottawa River and were significantly higher at the Sandspit and Rolphton than at Mackey and Cotnam Island (p<0.001). Mercury concentrations from the four sites are comparable to concentrations in other Ontario and Quebec lakes. It is advisable therefore, that consumers follow the fish consumption guidelines issued by provincial authorities when eating fish from the Ottawa River. Organo-chlorine compounds were not detected in walleye; however, they were detected in all eight of the pike collected at Cotnam Island. The highest organo-chlorine concentrations were measured in two

How burial diagenesis of chalk sediments controls sonic velocity and porosity

DEFF Research Database (Denmark)

Fabricius, Ida Lykke

2003-01-01

Based on P-wave velocity and density data, a new elastic model for chalk sediments is established. The model allows the construction of a series of isoframe (IF) curves, each representing a constant part of the mineral phase contributing to the solid frame. The IF curves can be related to the pro......Based on P-wave velocity and density data, a new elastic model for chalk sediments is established. The model allows the construction of a series of isoframe (IF) curves, each representing a constant part of the mineral phase contributing to the solid frame. The IF curves can be related.......1 or higher. Upon burial, the sediments lose porosity by mechanical compaction, and concurrently, the calcite particles recrystallize into progressively more equant shapes. High compaction rates may keep the particles in relative motion, whereas low compaction rates allow the formation of contact cement...... this process testifies to the absence of chemical compaction by calcite-calcite pressure dissolution, as well as to the porosity-preserving effect of contact cementation. At sufficient burial stress, the presence of stylolites indicates that pressure dissolution takes place between calcite., and silicates...

Cancer and workers' compensation at Chalk River nuclear laboratories

International Nuclear Information System (INIS)

Evans, D.W.S.

1985-01-01

This paper describes the circumstances leading to the notification to the Worker's Compensation Board of Ontario of two cases of cancer, both involving the lymphatic and haematoporetic systems, in employees at Chalk River Nulcear Laboratories. Twenty of these neoplasms are known to have occurred in the CRNL population between 1966 and 1983. The leukemia/lymphoma ratio observed in the twenty neoplasms is similar to that found in populations not occupationally exposed to ionizing radiation. The possible relationship between asbestos exposure and lymphoid neoplasms was discussed. 5 refs

Temporal variability of micro-organic contaminants in lowland chalk catchments: New insights into contaminant sources and hydrological processes.

Science.gov (United States)

Manamsa, K; Lapworth, D J; Stuart, M E

2016-10-15

This paper explores the temporal variation of a broad suite of micro organic (MO) compounds within hydrologically linked compartments of a lowland Chalk catchment, the most important drinking water aquifer in the UK. It presents an assessment of results from relatively high frequency monitoring at a well-characterised site, including the type and concentrations of compounds detected and how they change under different hydrological conditions including exceptionally high groundwater levels and river flow conditions during 2014 and subsequent recovery. This study shows for the first time that within the Chalk groundwater there can be a greater diversity of the MOs compared to surface waters. Within the Chalk 26 different compounds were detected over the duration of the study compared to 17 in the surface water. Plasticisers (0.06-39μg/L) were found to dominate in the Chalk groundwater on 5 visits (38.4%) accounting for 14.5% of detections but contributing highest concentrations whilst other compounds dominated in the surface water. Trichloroethene and atrazine were among the most frequently detected compounds. The limit for the total pesticide concentration detected did not exceed EU/UK prescribed concentration values for drinking water. Emerging organic compounds such as caffeine, which currently do not have water quality limits, were also detected. The low numbers of compounds found within the hyporheic zone highlight the role of this transient interface in the attenuation and breakdown of the MOs, and provision of an important ecosystem service. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

Mechanical and chemical processes affecting the chalk during burial, insights from combined reflection seismics, well data and field work

DEFF Research Database (Denmark)

Moreau, Julien; Boussaha, Myriam; Thibault, Nicolas Rudolph

2014-01-01

and cores analyses, respectively.However, few sites allow to combine all the different scale of observation for chalk diagenesis. Onshore and offshore high resolution seismics, two fully cored >350 m wells with wireline logging tools and very high quality exposures from a coastal cliff and a quarry form...... works have been performed with astronomical calibration based on stable isotope stratigraphy, wireline logs as well as several palaeontological proxies and detailed sedimentological analysis. Since a couple of decades, a specific kind of fractures has been described in the Chalk of Denmark, the so...

Origin of channel systems in the Upper Cretaceous chalk group of the Paris Basin

DEFF Research Database (Denmark)

Esmerode, E. V.; Surlyk, Finn

2009-01-01

the presence of at least two distinct intra-chalk discordant reflections: a Top Santonian and a Mid-Campanian reflection. These reflections are in places associated with up to 120-m-deep channel-like structures trending preferentially N-S and NW-SE. The Mid-Campanian reflection is also sporadically associated...... with a massive secondary dolomite layer, the thicknesses of which may reach 110 m. Diagenesis does not seem to account for the formation of the discordant reflections, as there is neither a one-to-one relationship between the dolomite and discordant reflections, nor are there signs of systematic collapse...... is suggested due to the uninterrupted deep-marine chalk facies below and above both unconformities, and the unrealistically large sea-level drop of more than 200 m, which would be necessary for subaerial exposure of the central Paris Basin during the Campanian. The channels are oriented parallel to the margins...

Integrated seismic analysis of the Chalk Group in eastern Denmark—Implications for estimates of maximum palaeo-burial in southwest Scandinavia

DEFF Research Database (Denmark)

Nielsen, Lars; Boldreel, Lars Ole; Hansen, Thomas Mejer

2011-01-01

Group. The sonic velocities are consistent with the overall seismic layering, although they show additional fine-scale layering. Integration of gamma and sonic log with porosity data shows that seismic velocity is sensitive to clay content. In intervals near boundaries of the refraction model, moderate......The origin of the topography of southwest Scandinavia is subject to discussion. Analysis of borehole seismic velocity has formed the basis for interpretation of several hundred metres of Neogene uplift in parts of Denmark.Here, refraction seismic data constrain a 7.5km long P-wave velocity model...... of the Chalk Group below the Stevns peninsula, eastern part of the Danish Basin. The model contains four layers in the ~860m thick Chalk Group with mean velocities of 2.2km/s, 2.4km/s, 3.1km/s, and 3.9–4.3km/s. Sonic and gamma wireline log data from two cored boreholes represent the upper ~450m of the Chalk...

A review of geophysical investigations at the site of Chalk River Nuclear Laboratories, Ontario

International Nuclear Information System (INIS)

Thomas, M.D.; Hayles, J.G.

1988-01-01

The site of the Chalk River Nuclear Laboratories was one of the first research areas located on crystalline rocks to be extensively investigated under the Canadian Nuclear Fuel Waste Management Program. A large contribution to meeting the geoscientific objectives of the program has been made using a suite of geophysical techniques. Many of them are standard, though sometimes modified in terms of instrumentation and/or experimental and/or analytical procedures, to meet the particular needs of the waste management program. Relatively new techniques have also been employed. Much of the early evaluation and development of the various techniques took place at the Chalk River site. Standard methods such as gravity, magnetics and seismic sounding have been used to investigate bedrock structure, and the seismic method has also been used to estimate overburden thickness. Standard geophysical borehole logging has been used to obtain in situ estimates of physical properties, to locate fracture zones and to make hole to hole correlations that have helped define local structure. Several standard electrical (e.g. resitivity) and electromagnetic (e.g. VLF-EM) techniques have proven successful in identifying water-filled fractures and faults. Relatively new techniques introduced into the geophysics at Chalk River were: ground probing radar; to investigate overburden; borehole TV and acoustic televiewer and VLF-EM, to locate fractures; studies of seismic tube-waves, well tides and temperature logs, to investigate fracture location and permeability. Most of these methods have been successful and are now routinely employed at other research sites

Fluid substitution studies for North Sea chalk logging data

DEFF Research Database (Denmark)

Gommesen, Lars; Mavko, G.; Mukerji, T.

2002-01-01

We have tested the application of respectively the Kuster-Toksöz and the Gassmann theory as a tool for predicting pore fluid from the elastic properties of brine-saturated North Sea reservoir chalk. We confirm that the Kuster-Toksöz model predicts a larger fluid effect thant the Gassmann model......, and show that the Kuster-Toksöz model fails to predict the presence of hydrocarbons. The Gassmann prediction for the near and potentially invaded zone corresponds more closely to logging data, than the Gassmann prediction for the far, virgin zone. We hereby conclude that the Gassmann theory predicts...

Sedimentology of the Upper Maastrichtian chalk, Danish Central Graben. M-10X (Dan Field), E-5X (Tyra SE Field) facies and core logs

Energy Technology Data Exchange (ETDEWEB)

Ineson, J.R.

2004-07-01

Based on detailed logs presented here at 1:10, the cored Upper Maastrichtian succession of the M-10X (Dan Field) and E-5X (Tyra SE Field) wells in the southern Danish Central Graben is subdivided into eight lithofacies and five ichnofabrics. The dominant bioturbated or laminated chalk mudstones and subordinate sparse skeletal wackestones are largely the result of pelagic carbonate production, sedimented by suspension settling and small volume, low density turbidity currents. Evidence of winnowing/reduced sedimentation rates is yielded by rare incipient hardgrounds; a well-developed mature hardground profile is developed at the Cretaceous-Danian boundary (the ''Maastrichtian hardground''). Rare marl laminae are recorded and a discrete marly chalk bed associated with an interval of finegrained skeletal chalk wackestones near the top of the Maastrichtian is recognised in both wells. Comparison between the two wells demonstrates that the m-scale laminated-bioturbated chalk cycles described from the Dan Field area are both stratigraphically and areally restricted; this has implications for both cyclostratigraphic correlation and reconstruction of depositional environments and Late Maastrichtian evolution of the Danish Central Graben. (au)

The dynamic analysis facility at the Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Argue, D.S.; Howatt, W.T.

1979-10-01

The Dynamic Analysis Facility at the Chalk River Nuclear Laboratories (CRNL) of Atomic Energy of Canada Limited (AECL) comprises a Hybrid Computer, consisting of two Applied Dynamic International AD/FIVE analog computers and a Digital Equipment Corporation (DEC) PDP-11/55 digital computer, and a Program Development System based on a DEC PDP-11/45 digital computer. This report describes the functions of the various hardware components of the Dynamic Analysis Facility and the interactions between them. A brief description of the software available to the user is also given. (auth)

Aerobic degradation potential of the herbicides mecoprop, dichlorprop and bentazone in groundwater from chalk aquifers

DEFF Research Database (Denmark)

Levi, Suzi; Hybel, Anne-Marie; Bjerg, Poul Løgstrup

2011-01-01

The aerobic degradation potential of mecoprop, dichlorprop and bentazone was studied at concentration of 1 μg/L in laboratory batch experiments with groundwater from chalk aquifers. Within the incubation period of 129 days, 14C-mecoprop concentration decreased to 60-80% in the microcosms with gro...

Determination of naturally radioactive elements in chalk sticks by means of gamma spectroscopy

Science.gov (United States)

Abd El-Wahab, Magda; Morsy, Zeinab; El-Faramawy, Nabil

2010-04-01

The radiation hazards due to ingestion of chalkboard dust were investigated. Sixteen samples from three different origin fabricates were used. The estimation of radiation hazard indices were based on the evaluation of the concentration activities of the natural radionuclides 238U, 232Th and 40K. The radium equivalent activity, external hazard index, internal hazard index and the annual dose equivalent associated with the radionuclides were calculated and compared with international recommended values to assess the radiation hazard. The values of internal and external radiation hazard indices were found to be less than unity. The annual effective dose rate obtained, E eff, and the annual gonadal dose equivalent (AGDE) are found to be less than the limit of the doses recommended by the International Commission on Radiological Protection for the general public. The analytical results show that besides the main calcium content, some toxic elements, S, Mo and Pb and Ni and Pb, in the Egyptian and imported chalk stocks, respectively, existed.

Acoustic and Petrophysical Evolution of Organic-Rich Chalk Following Maturation Induced by Unconfined Pyrolysis

Science.gov (United States)

Shitrit, Omri; Hatzor, Yossef H.; Feinstein, Shimon; Vinegar, Harold J.

2017-12-01

Thermal maturation is known to influence the rock physics of organic-rich rocks. While most studies were performed on low-porosity organic-rich shales, here we examine the effect of thermal maturation on a high-porosity organic-rich chalk. We compare the physical properties of native state immature rock with the properties at two pyrolysis-simulated maturity levels: early-mature and over-mature. We further evaluate the applicability of results from unconfined pyrolysis experiments to naturally matured rock properties. Special attention is dedicated to the elastic properties of the organic phase and the influence of bitumen and kerogen contents. Rock physics is studied based on confined petrophysical measurements of porosity, density and permeability, and measurements of bedding-normal acoustic velocities at estimated field stresses. Geochemical parameters like total organic carbon (TOC), bitumen content and thermal maturation indicators are used to monitor variations in density and volume fraction of each phase. We find that porosity increases significantly upon pyrolysis and that P wave velocity decreases in accordance. Solids density versus TOC relationships indicate that the kerogen increases its density from 1.43 to 1.49 g/cc at the immature and early-mature stages to 2.98 g/cc at the over-mature stage. This density value is unusually high, although increase in S wave velocity and backscatter SEM images of the over-mature samples verify that the over-mature kerogen is significantly denser and stiffer. Using the petrophysical and acoustic properties, the elastic moduli of the rock are estimated by two Hashin-Shtrikman (HS)-based models: "HS + BAM" and "HS kerogen." The "HS + BAM" model is calibrated to the post-pyrolysis measurements to describe the mechanical effect of the unconfined pyrolysis on the rock. The absence of compaction in the pyrolysis process causes the post-pyrolysis samples to be extremely porous. The "HS kerogen" model, which simulates a

Origin of nickel in water solution of the chalk aquifer in the north of France and influence of geochemical factors

Science.gov (United States)

Bernard, Daniel; El Khattabi, Jamal; Lefevre, Emilie; Serhal, Hani; Bastin-Lacherez, Sabine; Shahrour, Isam

2008-01-01

In the north of France, high registers of nickel are sometimes recorded within the chalk aquifer. In a confined context, the presence of pyrite in the covering clays or in the marcasite nodules encrusted in the clay may constitute a natural source of trace metals. With an objective of sanitary control, the limits of chemical contents regulating the quality of water destined for human consumption have been lowered by the European Framework Directive in the field of water policy (2000/60/EC). As a result, nickel limits have been reduced from 50 to 20 μg/l. The analyses, carried out on three water catchment fields in our area of study, were centred on variable parameters (Eh, O2(d), pH, Conductivity, T°), major elements (SO4, NO3) and metals (Fe, Ni, Mn, Co). The acquired data enabled us to identify from one hand, the conditions which are presented within the site, special thanks to the evolution of nitrate and iron contents and on the other hand, the natural origin (geological) of nickel for two of the three sites studied based essentially on the evaluation of the Nickel/Cobalt ratio. Thus, on the first site, the evolution of nickel content and nitrate content showed the influence of the phenomenon of denitrification on the re-mobilisation of the nickel. Whereas on the second site, a high variation of total iron content and oxygen dissolved in solution highlighted a particular phenomenon of oxidation of the pyrite through molecular oxygen. Finally, the correlation with the sulphates clearly showed behaviour of the nickel, once released, that was entirely dependent on the phenomenon of adsorption on the iron and manganese hydroxides.

Water movements in the unsaturated zone and recharge of the aquifer in the Champagne Chalk (France): Isotopic and chemical approaches

International Nuclear Information System (INIS)

Vachier, P.; Dever, L.; Fontes, J.C.

1987-01-01

Water from the unsaturated zone in the chalk, obtained from porous plugs, was subjected to chemical and isotope analyses over a three-year period. Tensiometric and volumetric water content measurements were carried out at the same time. The results obtained make it possible to establish an outline of the hydrodynamics of this porous, fissured chalk medium. Matrix porosity was 0.42 while fissure porosity was in the region of 0.01. The tritium and nitrate concentrations in the water fix the mean residence time in the 20-metre unsaturated zone at about 30 years. The isotope profiles ( 18 O and 3 H) and their downward displacements make it possible to estimate the mean annual recharge into the unconfined groundwater in the chalk (200 to 300 mm, depending on plant cover). The vertical movement of the solution in the porous matrix is dominated by the piston effect. Variations in 18 O concentration can be correlated with local climatic fluctuations. The recharge period runs from November to March, with summer rainfall playing no part. A comparison of 2 H and 18 O concentrations shows that even winter rainfall is partially removed by evaporation. (author). 17 refs, 11 figs, 1 tab

Investigation of spore forming bacterial flooding for enhanced oil recovery in a North Sea chalk Reservoir

DEFF Research Database (Denmark)

Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna

2015-01-01

Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focuses on core flooding experiments designed to see microbial plugging and its effect on oil recovery. A pressure tapped core holder was used for this purpose. A spore forming bacteria...... Bacillus licheniformis 421 was used as it was shown to be a good candidate in a previous study. Bacterial spore can penetrate deeper into the chalk rock, squeezing through the pore throats. Our results showed that injection of B. licheniformis 421 as a tertiary oil recovery method, in the residual oil...... saturation state, was able to produce additionally 1.0-2.3% original oil in place (OOIP) in homogeneous cores and 6.9-8.8% OOIP in heterogeneous cores. In addition, the pressure gradient was much higher in the heterogeneous cores, which confirms that bacterial selective plugging plays an important role...

COMPARISON OF THE TRADITIONAL CHALK AND BOARD LECTURE SYSTEM VERSUS POWER POINT PRESENTATION AS A TEACHING TECHNIQUE FOR TEACHING GROSS ANATOMY TO THE FIRST PROFESSIONAL MEDICAL STUDENTS

OpenAIRE

Nusrat; Abdul

2015-01-01

Traditionally and conventionally, gross anatomy is taught by lectures and cadaveric dissection and the lectures are taken with chalk and board (C&B) or chalk and talk method in, India. But there is always a debate over the most effective method of lecture delivery. AIM : The aim of this study was to compare the role and effecti...

Estimation of groundwater recharge to chalk and sandstone aquifers using simple soil models

Science.gov (United States)

Ragab, R.; Finch, J.; Harding, R.

1997-03-01

On the assumption that the water draining below the root zone is potentially available for groundwater recharge, two current UK methods for estimating annual groundwater recharge have been compared with a new soil model using data from four sites under permanent grass in the UK: two sites representative of the Chalk aquifer at Bridgest Farm (Hampshire) and Fleam Dyke (Cambridgeshire), and two sites on the Triassic sandstone at Bicton College (Devon) and Bacon Hall (Shropshire). A Four Root Layers Model (FRLM), the Penman-Grindley model and the UK Meteorological Office Rainfall and Evaporation Calculation System (MORECS) were used. The new soil model was run with potential evaporation as input both from the MORECS and from the Penman-Monteith equation. The models were run for the Chalk sites both with and without a bypass flow of 15% of rainfall. Bypass was not considered for the sandstone sites. The performance of the models was tested against neutron probes measurements of soil moisture deficits. In addition, the annual groundwater recharge estimated from the models was compared with the published values obtained from the 'zero flux plane' method. Generally, the Penman-Grindley model was more successful in predicting the time for soil to return to its field capacity than in predicting the magnitude of the soil moisture deficit. The annual groundwater recharge was predicted with reasonable accuracy. The MORECS relatively tended to overestimate the soil moisture deficits and to delay the time at which the soil returns to its field capacity. The consequences were underestimates of annual groundwater recharge, owing either to the higher values of potential evaporation calculated from the MORECS or tothe high available water capacity values associated with the soils under consideration. The new soil model (FRLM) predicts the soil moisture deficits successfully and hence is reliable in estimating the annual groundwater recharge. The model is capable of doing this with

Measuring and Modeling the Displacement of Connate Water in Chalk Core Plugs during Water Injection

DEFF Research Database (Denmark)

Korsbech, Uffe C C; Aage, Helle Karina; Andersen, Bertel Lohmann

2006-01-01

and forms a mixed water bank with almost 100% connate water in the front behind which a gradual transition to pure injection water occurs. This result underpins log interpretations from waterflooded chalk reservoirs. An ad hoc model was set up by use of the results, and the process was examined...

Field studies of radionuclide transport at the Chalk River Laboratories

International Nuclear Information System (INIS)

Champ, D.R.; Killey, R.W.D.; Moltyaner, G.L.

1991-01-01

In this paper the authors summarize the results of: in situ field column experiments to study the transport behaviour of several long-lived radionuclides, 4 natural gradient non-reactive radiotracer injection experiments at the Chalk River Laboratories (CRL) Twin Lake Tracer Test Site, and a model validation study that used data for 90 Sr from two well-defined contaminated groundwater flow systems at CRL. The paper also describes a current re-evaluation of radionuclide release and transport from a 1960 experimental burial (in a CRL sand aquifer) of glass blocks containing fission and activation products. (J.P.N.)

Deep saltwater in Chalk of North-West Europe: origin, interface characteristics and development over geological time

DEFF Research Database (Denmark)

Bonnesen, Ellen Prip; Larsen, F.; Sonnenborg, T.O.

2009-01-01

High-concentration saltwaters occur in many places in the regional Chalk aquifers of North-West Europe; to investigate deep occurrences, profiles of interstitial porewater chemistry have been studied from three 250-450m deep cores drilled in the eastern parts of Zealand, Denmark. At the studied...

The Chalk River Tritium Extraction Plant

International Nuclear Information System (INIS)

Holtslander, W.J.; Harrison, T.E.; Spagnolo, D.A.

1990-01-01

The Chalk River Tritium Extraction Plant for removal of tritium from heavy water is described. Tritium is present in the heavy water from research reactors in the form of DTO at a concentration in the range of 1-35 Ci/kg. It is removed by a combination of catalytic exchange to transfer the tritium from DTO to DT, followed by cryogenic distillation to separate and concentrate the tritium to T 2 . The tritium product is reacted with titanium and packaged for transportation and storage as titanium tritide. The plant processes heavy water at a rate of 25 kg/h and removes 80% of the tritium and 90% of the protium per pass. Catalytic exchange is carried out in the liquid phase using a proprietary wetproofed catalyst. The plant serves two roles in the Canadian fusion program: it produces pure tritium for use in fusion research and development, and it demonstrates on an industrial scale many of the tritium technologies that are common to the tritium systems in fusion reactors (author)

The Chalk River Tritium Extraction Plant

Energy Technology Data Exchange (ETDEWEB)

Holtslander, W J; Harrison, T E; Spagnolo, D A

1990-07-01

The Chalk River Tritium Extraction Plant for removal of tritium from heavy water is described. Tritium is present in the heavy water from research reactors in the form of DTO at a concentration in the range of 1-35 Ci/kg. It is removed by a combination of catalytic exchange to transfer the tritium from DTO to DT, followed by cryogenic distillation to separate and concentrate the tritium to T{sub 2}. The tritium product is reacted with titanium and packaged for transportation and storage as titanium tritide. The plant processes heavy water at a rate of 25 kg/h and removes 80% of the tritium and 90% of the protium per pass. Catalytic exchange is carried out in the liquid phase using a proprietary wetproofed catalyst. The plant serves two roles in the Canadian fusion program: it produces pure tritium for use in fusion research and development, and it demonstrates on an industrial scale many of the tritium technologies that are common to the tritium systems in fusion reactors (author)

Understanding Fluid Flow during Tectonic Reactivation: An Example from the Flamborough Head Chalk Outcrop (UK

Directory of Open Access Journals (Sweden)

O. Faÿ-Gomord

2018-01-01

Full Text Available Flamborough Head chalks are located at the extremities of E-W and N-S trending fault systems along the Yorkshire coast (UK. Rock deformation is expressed in Selwicks Bay where a normal fault is exposed along with a high density of calcite veins. The fault mineralization is tested using geochemistry. Crosscutting relationships are used to differentiate between three vein generations: a network of parallel veins that are oriented perpendicular to stratigraphy (Group I, hydraulic breccia with typical jigsaw puzzle structure (Group II, and a third generation of calcite veins crosscutting the two previous generations (Group III. Geochemical analyses revealed that all three generations possess the same chemical signature and must reflect successive pulses from the same mineralizing fluid source. Strontium isotope analyses showed that the veins have elevated 87Sr/86Sr ratios, that is, up to 7.110, while ratios of the chalk matrix equal 7.707. The latter value is in agreement with the signature of Late Cretaceous seawater. Consequently, the source of the fluid is external, reflecting an open system. The radiogenic Sr-isotope ratios, combined with low iron concentration, suggest that fluids migrated through sandy deposits. Fluid inclusion salinities range from 0 to 12 eq. wt% NaCl equiv. with a dominance of very low salinity inclusions, reflecting a meteoric signal. This leads to a model where meteoric fluids stored in an underlying confined sandstone aquifer were remobilized. The wide range of salinities could result from mixing of the meteoric fluid with some more saline fluids present in the rock sequence or from the dissolution of salts in the subsurface. In addition to the understanding of the local paragenetic evolution of the veining in Flamborough Head chalks, this study offers an insight into the way how fluid flows and mineralizes along fault zones.

Modelling flow and heat transfer through unsaturated chalk - Validation with experimental data from the ground surface to the aquifer

Science.gov (United States)

Thiéry, Dominique; Amraoui, Nadia; Noyer, Marie-Luce

2018-01-01

During the winter and spring of 2000-2001, large floods occurred in northern France (Somme River Basin) and southern England (Patcham area of Brighton) in valleys that are developed on Chalk outcrops. The floods durations were particularly long (more than 3 months in the Somme Basin) and caused significant damage in both countries. To improve the understanding of groundwater flooding in Chalk catchments, an experimental site was set up in the Hallue basin, which is located in the Somme River Basin (France). Unsaturated fractured chalk formation overlying the Chalk aquifer was monitored to understand its reaction to long and heavy rainfall events when it reaches a near saturation state. The water content and soil temperature were monitored to a depth of 8 m, and the matrix pressure was monitored down to the water table, 26.5 m below ground level. The monitoring extended over a 2.5-year period (2006-2008) under natural conditions and during two periods when heavy, artificial infiltration was induced. The objective of the paper is to describe a vertical numerical flow model based on Richards' equation using these data that was developed to simulate infiltrating rainwater flow from the ground surface to the saturated aquifer. The MARTHE computer code, which models the unsaturated-saturated continuum, was adapted to reproduce the monitored high saturation periods. Composite constitutive functions (hydraulic conductivity-saturation and pressure-saturation) that integrate the increase in hydraulic conductivity near saturation and extra available porosity resulting from fractures were introduced into the code. Using these composite constitutive functions, the model was able to accurately simulate the water contents and pressures at all depths over the entire monitored period, including the infiltration tests. The soil temperature was also accurately simulated at all depths, except during the infiltrations tests, which contributes to the model validation. The model was used

A review of analytical techniques for the determination of carbon-14 in environmental samples

International Nuclear Information System (INIS)

Milton, G.M.; Brown, R.M.

1993-11-01

This report contains a brief summary of analytical techniques commonly used for the determination of radiocarbon in a variety of environmental samples. Details of the applicable procedures developed and tested in the Environmental Research Branch at Chalk River Laboratories are appended

Effluent and environmental monitoring of Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Pilgrim, T.; De Waele, C.; Gallagher, C. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2014-07-01

Atomic Energy of Canada Limited's (AECL's) Environmental Protection Program has been gathering environmental monitoring data at its Chalk River Laboratories (CRL) for over 60 years. The comprehensive effluent and environmental monitoring program at CRL consists of more than 600 sampling locations, including the Ottawa River, with approximately 60,000 analyses performed on air and liquid effluent parameters each year. Monitoring for a variety of radiological and non-radiological parameters is regularly conducted on various media, including ambient air, foodstuff (e.g. milk, fish, garden produce, large game, and farm animals), groundwater, Ottawa River water and other surface water on and off-site. The purpose of the monitoring program is to verify that past and current radiological and non-radiological emissions derived from AECL operations and activities, such as process water effluent into the Ottawa River, are below regulatory limits and demonstrate that CRL operations do not negatively affect the quality of water on or leaving the site. In fact, ongoing program reports demonstrate that radiological emissions are well below regulatory limits and have been declining for the past five years, and that non-radiological contaminants do not negatively affect the quality of water on and off the site. Two updated Canadian Standards Association (CSA) standards for Effluent and Environmental monitoring have come into effect and have resulted in some changes to the AECL Program. This presentation will discuss effluent and surface water monitoring results, the observed trends, the changes triggered by the CSA standards, and a path forward for the future. (author)

Life-history strategies as a tool to identify conservation constraints: A case-study on ants in chalk grasslands

NARCIS (Netherlands)

Noordwijk, C.G.E.; Boer, P.; Mabelis, A.A.; Verberk, W.C.E.P.; Siepel, H.

2012-01-01

Species’ life-history traits underlie species–environment relationships. Therefore, analysis of species traits, combined into life-history strategies, can be used to identify key factors shaping the local species composition. This is demonstrated in a case-study on ants in chalk grasslands. We

Derived release limits (DRL's) for airborne and liquid effluents from the Chalk River Nuclear Laboratories during normal operations

International Nuclear Information System (INIS)

Palmer, J.F.

1981-02-01

Derived release limits (DRL's), based on regulatory dose limits, have been calculated for routine discharges of radioactivity in airborne and liquid effluents from the Chalk River Nuclear Laboratories. Three types of sources of airborne effluents were considered: the NRX/NRU stack, the 61 m stack connected to the 99 Mo production facility, and a roof vent typical of those installed on several buildings on the site. Sources of liquid effluents to the Ottawa River were treated as a single source from the site as a whole. Various exposure pathways to workers on the site and to members of the public outside the site boundary were considered in the calculations. The DRL's represent upper limits for routine emissions of radioactivity from the Chalk River Nuclear Laboratories to the surrounding environment. Actual releases are regulated by Administrative Levels, set lower than the DRL's, and are confirmed by monitoring. (author)

Uranium-phosphate relationship in phosphated chalks of the Mons and Picardie Bassins

Energy Technology Data Exchange (ETDEWEB)

Quinif, Y; Charlet, J M; Dupuis, C; Robaszynski, F [Faculte Polytechnique de Mons (Belgium)

1981-11-30

The lithological and geochemical conditions relative to the ''Senonian'' phosphatic chalks are relatively simple in the Basins of Mons (Belgium) and of Picardy (France). Their characteristics permit us to study chiefly the uranium-phosphate relation. It appears a very good linear correlation between the phosphate and the uranium. The coefficient U/P/sub 2/O/sub 5/ remains a constant from the bottom to the top of the same section, but changes in space for synchronic formations (lateral variation of geochemical facies) and in time for two separated basins.

Proceedings of a workshop on geophysical and related geoscientific research at Chalk River, Ontario

International Nuclear Information System (INIS)

Thomas, M.D.; Dixon, D.F.

1989-10-01

A large part of the Canadian Nuclear Fuel Waste Management Program is geoscience research and development aimed at obtaining information to quantify the transport of radionuclides through the geosphere and at determining the geotechnical properties required for disposal vault design. The geosphere at potential disposal sites is characterized in part by the use of remote sensing (geophysical) methods. In 1977 public concern about the disposal of radioactive waste resulted in field work being restricted to the site of Chalk River Nuclear Laboratories, which was used to develop, evaluate and compare various techniques in order to optimize the methods for obtaining geoscience information. Methods tested at Chalk River are to be applied at other research sites. Most investigations have been carried out around Maskinonge Lake, using about thirty boreholes sink into bedrock. The boreholes provide subsurface geological information that can be used as a reference to compare the responses of various geophysical methods and equipment. Regional studies, including airborne geophysical surveys, have also been conducted. The 25 papers presented at this workshop provide comprehensive documentation of the most significant results of geophysical studies. The workshop also provided an evaluation of geophysical techniques and their utility to the Nuclear Fuel Waste Management Program

Tilting oil-water contact in the chalk of Tyra Field as interpreted from capillary pressure data

DEFF Research Database (Denmark)

Fabricius, Ida Lykke; Rana, M.A.

2010-01-01

The Tyra Field in the central North Sea is located in Palaeogene and Upper Cretaceous chalk. It contains a natural gas zone underlain by an oil leg. Based on analysis of logs and core data from ten wells drilled prior to the field being put into production, normalized water saturation depth-trend...... inequilibriumin the aquifer following tectonic tilting....

The Use of Hydrograph Analysis and Impulse Response Functions to Improve Understanding of Groundwater Flooding: A Case Study from the Chalk Aquifer, United Kingdom.

Science.gov (United States)

Ascott, M.; Bloomfield, J.; Macdonald, D.; Marchant, B.; McKenzie, A.

2017-12-01

The Cretaceous Chalk, the most important aquifer in the United Kingdom (UK) for public water supply, underlies many large cities in southern and eastern England including parts of London, however, it is prone to groundwater flooding. We have developed a new approach to analyse the spatio-temporal extent of groundwater flooding using statistical analysis of groundwater level hydrographs and impulse response functions (IRFs) applied to a major Chalk groundwater flooding event in the UK during winter 2013/14. Using monthly groundwater levels for 26 boreholes in the Chalk and a new standardised index for groundwater flooding, we have: estimated standardised series; grouped them using k-means cluster analysis; and, cross-correlated the cluster centroids with the Standardised Precipitation Index accumulated over time intervals between 1 and 60 months. This analysis reveals two spatially coherent groups of standardised hydrographs which respond to precipitation over different timescales. We estimate IRF models of the groundwater level response to effective precipitation for three boreholes in each group. The IRF models support the SPI analysis showing different response functions between the two groups. If we apply identical effective precipitation inputs to each of the IRF models we see differences between the hydrographs from each group. It is proposed that these differences are due to the intrinsic, hydrogeological properties of the Chalk and of overlying relatively low permeability superficial deposits. Consequently, it is concluded that the overarching controls on groundwater flood response are a complex combination of antecedent conditions, rainfall and catchment hydrogeological properties. These controls should be taken into consideration when anticipating and managing future groundwater flood events.

Atmospherically dispersed radiocarbon at the Chalk River Laboratories

International Nuclear Information System (INIS)

Milton, G.M.; Brown, R.M.; Repta, C.J.W.; Selkirk, C.J.

1996-01-01

A small percentage of the total radiocarbon produced by the NRX and NRU experimental reactors at the Chalk River Laboratories has been vented from the main reactor stack and atmospherically dispersed across the site. Surveys conducted in 1982-83 and 1993-94 have shown that atmospheric levels more than 50 m from the stack are never greater than 600 Bq.kg -1 carbon above the natural background level, falling to near-global atmospheric levels at the site boundaries roughly 7 km away. A dispersion factor > 1.2 x 10 6 m 3 .s -1 at ∼ 0.75 km distance from the point of emission is calculated on the basis of recent in-stack monitoring. Analysis of growth rings in on-site trees has provided an opportunity to search for correlations of 14 C output summer power production and/or moderator losses. (author). 16 refs., 14 tabs., 11 figs

Drivers of abundance and community composition of benthic macroinvertebrates in Ottawa River sediment near Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Bond, M.J.; Rowan, D.; Silke, R.; Carr, J., E-mail: bondm@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2013-12-15

The Ottawa River has received effluent from Chalk River Laboratories (CRL) for more than 60 years. Some radionuclides and contaminants released in effluents are bound rapidly to particles and deposited in bottom sediments where they may be biologically available to benthic invertebrates and other aquatic biota. As part of a larger ecological assessment, we assess the potential impact of contaminated sediments in the vicinity of CRL on local benthic community structure. Using bivariate and multivariate approaches, we demonstrate that CRL operations have had little impact on the local benthic community. Despite elevated anthropogenic radionuclide activity concentrations in sediment near CRL's process outfall, the benthic community is no less abundant or diverse than what is observed upstream at background levels. The Ottawa River benthic invertebrate community is structured predominantly by natural physical and biological conditions in the sediment, specifically sediment water content and organic content. These natural habitat conditions have a stronger influence on macroinvertebrate communities than sediment contamination. (author)

Analysis of the Pelletron charging chain break in the Chalk River MP tandem accelerator

International Nuclear Information System (INIS)

Burn, N.; Greiner, B.F.; Coleman, C.E.

1980-11-01

On February 7, 1980 one of the three Pelletron charging chains in the Low Energy end of the Chalk River MP Tandem Accelerator broke during normal operation. The chains had been in use for 38 000 h at the time of the break. Tensile tests were carried out on pieces of the broken chain as well as unused pieces of chain. Several possible reasons for the chain break are suggested; ways of improving performance and reliability are proposed. (auth)

Impedance imaging in core analysis. Imaging of phase distributions in samples of natural cores of North Sea chalk containing conducting as well as non-conducting fluids. Part 1: Development of prototype measurement cell

Energy Technology Data Exchange (ETDEWEB)

Moeller Nielsen, C. [DTU, Inst. for Kemi (Denmark); Lauersen, S. [DTU, Lab. for Energiteknik (Denmark)

1996-12-31

To make reservoir simulations it is necessary to know such parameter functions as the capillary pressure curve, relative permeabilities etc. These are difficult to measure in chalk by means of traditional techniques because of the low permeability. In the present approach a displacement process is studied in detail and computer simulation with reservoir simulators can be used to determine parameter functions. To do this, however, it is necessary to know the developments of saturation profiles during the experiment. Different methods are tested in the programme. NMR-scanning and {gamma}-logging are methods where straight rays penetrate the sample and are partly absorbed. In electric current imaging an electric field is induced in the sample and detected at the surface. There are several benefits of this method compared with the others: There are no special safety requirements in contrast to work with radiation; No expensive and limited available equipment is needed unlike NMR; There are no intrinsic procedures slowing the method. There are, however, also drawbacks: Making measurements on a core sample implies the application of a large number of minute electrodes. To do this an implementation has to be derived from scratch; The inverse problem, i.e. the determination of the field inside the sample from surface measurements, is more difficult than the inverse problem of straight ray absorption. In the present report the development of an experimental technique is described. In part II of the report the interpretation of the experimental results will be discussed. (EG) 21 refs.

Field burial results and SIMS analysis of the Chalk River glass blocks

International Nuclear Information System (INIS)

Tait, J.C.; Hocking, W.H.; Betteridge, J.S.; Bart, G.

1986-01-01

In 1959, 25 2-kg hemispherical blocks of aluminosilicate glass, each containing ∼90 MBq/g of mixed fission products, were buried in a sandy soil aquifer in the waste management area at the Chalk River Nuclear Laboratories. A second set of blocks, containing ∼260 MBq/g mixed fission products, was buried in 1960. One block from each test was retrieved in 1978 to undergo chemical and surface analysis. This report reviews the migration of the 90 Sr and 137 Cs plume in the soil and presents the results of SIMS depth profiling of the surface of a glass block. (author)

Status of the Chalk River superconducting heavy-ion cyclotron

International Nuclear Information System (INIS)

Ormrod, J.H.; Bigham, C.B.; Heighway, E.A.; Hoffmann, C.R.; Hulbert, J.A.; Schneider, H.R.

1982-01-01

The Chalk River four-sector K=520 superconducting cyclotron is designed to accelerate all ions from lithium (to 50 MeV/u) to uranium (to 10 MeV/u) using a 13 MV tandem Van de Graaff as injector. After an extended shutdown the magnet has been reassembled and field measurements resumed. During the shutdown a ground fault between the superconducting coil and its container was removed, the flutter poles were shimmed and the remaining trim rod holes were bored in them, the 104 trim rods with their holders were installed and the cryostat inner wall was modified to accept the radiofrequency accelerating structure. Experiments on the radiofrequency accelerating system, cryopumps, electrostatic deflector and superconducting windings for the magnetic channel are done in separate test chambers. Recent results and the status of all subsystems are given

Towards an improved lithostratigraphic subdivision of the chalk group in the Netherlands North Sea area - A seismic stratigraphic approach

NARCIS (Netherlands)

Molen, A.S. van der; Wong, Th.E.

2007-01-01

In the Netherlands North Sea area, the Chalk Group has thus far been subdivided into the Cenomanian Texel Formation, the Turonian to Maastrichtian Ommelanden Formation and the Danian Ekofisk Formation. This paper describes the attempt to arrive at a more detailed lithostratigraphic subdivision for

Programme of research into the management and storage of radioactive waste. Single fracture experiment at Chalk River

International Nuclear Information System (INIS)

Bourke, P.J.

1984-01-01

A field experiment was carried out at Chalk river to measure the transport of bromine and strontium through a fracture in granite. Retardation of strontium transport by sorption onto the rock was also measured. Data was obtained for bromine but no useful data was obtained for strontium due to failure of the hydraulic equipment. (U.K.)

Spatial analysis of Carbon-14 dynamics in a wetland ecosystem (Duke Swamp, Chalk River Laboratories, Canada)

International Nuclear Information System (INIS)

Yankovich, T.L.; King-Sharp, K.J.; Carr, J.; Robertson, E.; Killey, R.W.D.; Beresford, N.A.; Wood, M.D.

2014-01-01

A detailed survey was conducted to quantify the spatial distribution of 14 C in Sphagnum moss and underlying soil collected in Duke Swamp. This wetland environment receives 14 C via groundwater pathways from a historic radioactive Waste Management Area (WMA) on Atomic Energy Canada Limited (AECL)'s Chalk River Laboratories (CRL) site. Trends in 14 C specific activities were evaluated with distance from the sampling location with the maximum 14 C specific activity (DSS-35), which was situated adjacent to the WMA and close to an area of groundwater discharge. Based on a spatial evaluation of the data, an east-to-west 14 C gradient was found, due to the influence of the WMA on 14 C specific activities in the swamp. In addition, it was possible to identify two groups of sites, each showing significant exponential declines with distance from the groundwater source area. One of the groups showed relatively more elevated 14 C specific activities at a given distance from source, likely due to their proximity to the WMA, the location of the sub-surface plume originating from the WMA, the presence of marsh and swamp habitat types, which facilitated 14 C transport to the atmosphere, and possibly, 14 C air dispersion patterns along the eastern edge of the swamp. The other group, which had lower 14 C specific activities at a given distance from the groundwater source area, included locations that were more distant from the WMA and the sub-surface plume, and contained fen habitat, which is known to act as barrier to groundwater flow. The findings suggest that proximity to source, groundwater flow patterns and habitat physical characteristics can play an important role in the dynamics of 14 C being carried by discharging groundwater into terrestrial and wetland environments. - Highlights: • Groundwater represents an important source of volatile radionuclides to wetlands. • Habitat type influenced 14 C transport from sub-surface to surface environments. • C-14 specific

Overview of research in physics and health sciences at the Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Milton, J.C.D.

1988-01-01

Toxicology research was a logical extension of existing program at Chalk River. Research in radiotoxicology has been going on there since the early forties. An overview of the existing physics and health sciences research programs operating at the Research Company of Atomic Energy of Canada Limited was presented. Programs in nuclear physics, heavy ion nuclear physics, astrophysical neutrino physics, condensed matter physics, fusion, biology, dosimetry, and environmental sciences were briefly described. In addition, a description of the research company organization was provided

Stochastic modelling of porosity using seismic impedances on a volume of chalk in the Dan Field

Energy Technology Data Exchange (ETDEWEB)

Vejbaek, O.V.

1995-12-31

Seismic impedances calculated from logs show very good correlation to log porosities in wells penetrating the chalk reservoir in the Dan Field, Danish North Sea. This is the basis for an attempt to use seismic impedances derived from inversion as soft data for geostatistical reservoir characterization. The study focusses on porosity description of the Maastrichtian chalk reservoir unit, laterally restricted to an area covered by a subset of a 3D seismic survey. This seismic volume was inverted using the ISIS software producing a volume of seismic impedances. Spatial porosity realizations are produced using a gaussian collocated co-simulation algorithm, where well log porosities constitute the hard data input and seismic impedances are the soft data input. The simulated volume measures 1400 m x 1525 m x 102 m and is oriented parallel to lines and cross lines in the seismic dataset. Simulated blocks measures 25 m x 25 m x 6 m equivalent to twice the line and trace spacing, and approximately equivalent to the seismic sample rate. The correlation coefficient between log porosities and impedances calculated from logs alone are shown to be misleading since they suggest unrealistic high coefficients. However, the actual data used, namely inversion derived impedances and log porosities, still show correlation coefficients in the order of -0,45, which is quite sufficient to make the inversion results very useful. It is remarkable that the calculated correlation coefficient is based on 15 wells, and the inversion is based on only one well. The negative correlation coefficient indicate that high impedances correspond to low porosities and vice-versa. The impedance data indicate the level of average porosities at locations between wells. The fine structure is produced by the geostatistic process, with averages constrained by seismic impedances. The seismic impedances derived from the inversion process are thus shown to constitute useful primary data to constrain reservoir

Towards an improved lithostratigraphic subdivision of the Chalk Group in the Netherlands North Sea area – A seismic stratigraphic approach

NARCIS (Netherlands)

Molen, A.S. van der; Wong, Th.E.

In the Netherlands North Sea area, the Chalk Group has thus far been subdivided into the Cenomanian Texel Formation, the Turonian to MaastrichtianOmmelanden Formation and the Danian Ekofisk Formation. This paper describes the attempt to arrive at a more detailed lithostratigraphicsubdivision for

Cooling tower influence on the rainwater pH near a major power plant

Science.gov (United States)

Ta-Yung Li

1976-01-01

The dense network of 12 rainguages, covering an area of 6 km in diameter, was reinstalled near PEPCO's 710 MW Chalk Point power plant in southern Maryland. The rainwater samples were collected from July to December 1974. This second season's collection of rainwater samples were analyzed and results showed a general shifting of pH toward higher values since...

Electroosmotic dewatering of chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge

DEFF Research Database (Denmark)

Hansen, H.K.; Christensen, Iben Vernegren; Ottosen, Lisbeth M.

2003-01-01

. Casagrande's coefficients were determined for the four materials at different water contents. The experiments in this work showed that chalk could be dewatered from 40% to 79% DM (dry matter), fly ash from 75 to 82% DM, iron hydroxide sludge from 2.7 to 19% DM and biomass from 3 to 33% DM by electroosmosis....... The process was not optimised indicating that higher dry matter contents could be achieved by electroosmosis. It was possible to relate Casagrande's coefficient directly to the electroosmotic coefficient obtained by dewatering experiments....

An overview of the waste characterization program at Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Csullog, G.W.; Hardy, D.G.

1990-05-01

A comprehensive Waste Characterization Program (WCP) is in place at Chalk River Laboratories to support disposal projects. The WCP is responsible for: 1) specifying the manifests for waste shipments; 2) developing and maintaining central databases for waste inventories and analytical data; and 3) developing the technologies and procedures to characterize the radiological and the physical/chemical properties of wastes. WCP work is being performed under the umbrella of a newly developed waste management Quality Assurance (QA) program. This paper gives an overview of the WCP with an emphasis on the requirements for determining radionuclide inventories in wastes, for implementing record-keeping systems, and for maintaining a QA program for disposal operations

Foil changer for the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.E.; Proulx, D.R.; Weaver, J.F.

1985-01-01

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system

The Chalk River helium jet and skimmer system

International Nuclear Information System (INIS)

Schmeing, H.; Koslowsky, V.; Wightman, M.; Hardy, J.C.; MacDonald, J.A.; Faestermann, T.; Andrews, H.R.; Geiger, J.S.; Graham, R.L.

1976-01-01

A helium jet and skimmer system intended as an interface between a target location at the Chalk River tandem accelerator and the ion source of an on-line separator presently under construction has been developed. The system consists of a target chamber, a 125 cm long capillary, and a one stage skimmer chamber. The designs of the target and skimmer chambers allow one to vary a large number of independent flow and geometrical parameters with accurate reproducibility. Experiments with the β-delayed proton emitter 25 Si (tsub(1/2)=218 ms) produced in the reaction 24 Mg( 3 He,2n) 25 Si show that under optimized conditions about 75% of the reaction products leaving the target are transported to the skimmer. Of those, more than 90% pass through the skimmer orifice, which separates off 97.5% of the transport gas, helium. By introducing an additional helium flow across the skimming orifice the amount of helium separated off the transport jet can be increased to beyond 99.85%, leaving the high throughput of recoils unaffected. (Auth.)

Compaction monitoring in the Ekofisk area Chalk Fields

International Nuclear Information System (INIS)

Menghini, M.L.

1989-01-01

In late Nov. 1984, the subsidence phenomenon was recognized in the Ekofisk field. To determine the magnitude and areal extent of the formation compaction, a program for measuring compaction with electric logging tools was initiated. Initial time-lapse surveys performed with cased-hole neutron tools indicated that reservoir compaction was occurring, but the accuracy of the determination of compaction rate was low. In addition to the cased-hole neutron survey, radioactive markers and a gamma ray (GR) detection tool were used to determine compaction rate in the reservoir more accurately and to determine whether compaction was occurring in the overburden. A program for implanting radioactive-marker bullets and subsequent monitoring with a four-detector GR tool was implemented. There are currently 13 wells equipped with radioactive markers in the compaction monitoring program. Compaction monitoring accuracy using the four-detector GR tool was found to depend on wellbore geometry, completion design, and radioactive-marker placement. This paper gives the results of the program to date and describes the operational procedures and analysis techniques used for compaction monitoring in the greater Ekofisk area chalk fields

Combining Chalk Talk with PowerPoint to Increase In-class Student Engagement

Directory of Open Access Journals (Sweden)

Swati Betharia

2016-11-01

Full Text Available In striving to attain a higher degree of in-class student engagement, and target a larger number of preferred student-learning styles, this case study describes a multimodal teaching approach. PowerPoint slides have gradually gained popularity over the more traditional chalk and talk lecture design. The student population in today’s age seeks more non-passive modes of information delivery. Numerous novel approaches to enhance active learning, such as flipped classroom and problem-based learning, have recently been explored. While working well for therapeutic and lab-based courses, these formats may not be best-suited for all basic science topics. The importance of basic science in a pharmacy curriculum is well emphasized in the 2016 ACPE Standards. To actively involve students in a pharmacology lecture on diuretics, a session was designed to combine the PowerPoint and chalk talk approaches. Students created 10 concept diagrams following an instructor, who explained each step in the process using a document camera. For visual learners, these diagrams provided a layered representation of the information, gradually increasing in complexity. For learners with a preference for the reading learning style, the information was also available in corresponding PowerPoint slides. Scores from pre- and post-session quizzes indicated a high level of concept understanding and recall (median 1 [IQR 0 – 2] vs 4 [IQR 3 – 5]; p<0.001. The student perception survey data reported higher in-class attention levels (76%, an appreciation for the utility of self-created concept diagrams (88%, and a call for additional sessions being presented in this format (73%. Targeting a variety of student learning styles by using the active development of concept diagrams, in addition to traditional PowerPoint slides, can promote student engagement and enhance content understanding.   Type: Case Study

Stylolites, porosity, depositional texture, and silicates in chalk facies sediments

DEFF Research Database (Denmark)

Fabricius, Ida Lykke; Borre, Mai K.

2007-01-01

dissolution around 490 m below sea floor (bsf) corresponds to an interval of waning porosity-decline, and even the occurrence of proper stylolites from 830 m bsf is accompanied by only minor porosity reduction. Because opal is present, the pore-water is relatively rich in Si which through the formation of Ca......-silica complexes causes an apparent super-saturation of Ca and retards cementation. The onset of massive pore-filling cementation at 1100 m bsf may be controlled by the temperature-dependent transition from opal-CT to quartz. In the stylolite-bearing chalk of two wells in the Gorm and Tyra fields, the nannofossil...... matrix shows recrystallization but only minor pore-filling cement, whereas microfossils are cemented. Cementation in Gorm and Tyra is thus partial and has apparently not been retarded by opal-controlled pore-water. A possible explanation is that, due to the relatively high temperature, silica has...

Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge

DEFF Research Database (Denmark)

Anderskouv, Kresten; Surlyk, Finn

2011-01-01

, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab­sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites...... slump packages (14–18 in total) are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in slumping. The vertical succession of facies records an earliest Cenomanian facies shift from dominantly siliciclastic to chalk deposition...

Trace fossils of a cyclic chalk-marl succession; the upper Maastrichtian Rørdal Member, Denmark

DEFF Research Database (Denmark)

Lauridsen, Bodil Wesenberg; Surlyk, Finn; Bromley, Richard Granville

2011-01-01

Trace fossils from an upper Maastrichtian cyclic chalk–marl succession, the Rørdal Member, exposed in the Rørdal quarry, Denmark, are analysed in order to test whether the changes in substrate lithology exerted any control over the ichnodiversity, tiering complexity, and density of the infauna...... in the visibility of traces between chalk and marl and not due to differences in ecological stress upon the endobenthic community of the two lithologies. The study thus provides an excellent example of how the effect of taphonomic factors may give a misleading and biased impression of apparent differences...

Identifying evidence of climate change impact on extreme events in permeable chalk catchments

Science.gov (United States)

Butler, A. P.; Nubert, S.

2009-12-01

The permeable chalk catchments of southern England are vital for the economy and well being of the UK. Not only important as a water resource, their freely draining soils support intensive agricultural production, and the rolling downs and chalk streams provide important habitants for many protected plant and animal species. Consequently, there are concerns about the potential impact of climate change on such catchments, particularly in relation to groundwater recharge. Of major concern are possible changes in extreme events, such as groundwater floods and droughts, as any increase in the frequency and/or severity of these has important consequences for water resources, ecological systems and local infrastructure. Studies of climate change impact on extreme events for such catchments have indicated that, under medium and high emissions scenarios, droughts are likely to become more severe whilst floods less so. However, given the uncertainties in such predictions and the inherent variability in historic data, producing definitive evidence of changes in flood/drought frequency/severity poses a significant challenge. Thus, there is a need for specific extreme event statistics that can be used as indicators of actual climate change in streamflow and groundwater level observations. Identifying such indicators that are sufficiently robust requires catchments with long historic time series data. One such catchment is the River Lavant, an intermittent chalk stream in West Sussex, UK. Located within this catchment is Chilgrove House, the site of the UK’s longest groundwater monitoring well (with a continuous record of water level observations of varying frequency dating back to 1836). Using a variety of meteorological datasets, the behaviour of the catchment has been modelled, from 1855 to present, using a 'leaky aquifer' conceptual model. Model calibration was based on observed daily streamflow, at a gauging station just outside the town of Chichester, from 1970. Long

Foil changer for the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.F.; Proulx, D.R.; Weaver, J.F.

1985-01-01

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system

Electrostatic deflector development at the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Diamond, W.T.; Mitchel, G.R.; Almeida, J.; Schmeing, H.

1991-01-01

An electrostatic deflector is used to extract heavy-ion beans from the Chalk River superconducting cyclotron. Deflector voltages up to 100 kV across a 7 m gap (143 kV/cm) are needed to extract the full range of beams that the cyclotron is designed to accelerate. This goal remains a challenge, but substantial progress has been made over the past year. Voltages over 90 kV have been reliably maintained over a 7.5 mm gap with a magnetic field of 3 T. Voltages of 74 kV have been used with a reduced gap of 4.75 mm (corresponding to a field greater than 150 kV/cm) to extract beams with magnetic fields up to 4.25 T. Major progress was achieved when the authors introduced a water-cooled, negative high-voltage electrode, and changed the sparking plates and the thin septum from molybdenum to stainless steel. Efforts are continuing to attain a field of at least 143 kV/cm over a gap of at least 6 mm width

Diagenesis of silica-rich mounded chalk, the Coniacian Arnager Limestone, Denmark

DEFF Research Database (Denmark)

Buus Madsen, Heine; Stemmerik, Lars; Surlyk, Finn

2010-01-01

The Coniacian Arnager Limestone Formation is exposed on the Danish island of Bornholm in the Baltic Sea. It is composed of mound-bedded siliceous chalk, and X-ray diffraction and scanning electron microscopy indicate a content of 30-70% insoluble minerals, including authigenic opal-CT, quartz......, clinoptilolite, feldspars, calcite, dolomite, and barite. Opal-CT and clinoptilolite are the most common and constitute 16-53% and 2-9%, respectively. The content of insoluble minerals varies laterally bothwithinthemounds and inplanar beds, and the opal-CT content varies by up to 10% vertically. Themounds...... precipitation of opal-CT. The opal-CT formed at temperatures around 17°C, the precipitation lowered the silica activity and the Si/Al ratio of the pore water, resulting in precipitation of clinoptilolite, feldspar and smectite. Calcite formed synchronouslywith the latest clinoptilolite.Minoramounts of quartz...

Importance of small fishes and invasive crayfish in otter Lutra lutra diet in an English chalk stream

OpenAIRE

Britton, J.R.; Berry, M.; Sewell, S.; Lees, C.; Reading, P.

2017-01-01

The diet composition of the European otter Lutra lutra was assessed using spraint analysis in the Hampshire Avon, a lowland chalk stream in Southern England, over an 18-month period. Small cyprinid fishes were the main prey item taken in all seasons, with bullhead Cottus gobio and stone loach Barbatula barbatula also important; there were relatively few larger fishes of interest to fisheries found. There were significant seasonal differences in diet composition by season, with signal crayfish...

Experience with radioactive waste incineration at Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Le, V.T.; Beamer, N.V.; Buckley, L.P.

1988-06-01

Chalk River Nuclear Laboratories is a nuclear research centre operated by Atomic Energy of Canada Limited. A full-scale waste treatment centre has been constructed to process low- and intermediate-level radioactive wastes generated on-site. A batch-loaded, two-stage, starved-air incinerator for solid combustible waste is one of the processes installed in this facility. The incinerator has been operating since 1982. It has consistently reduced combustible wastes to an inert ash product, with an average volume reduction factor of about 150:1. The incinerator ash is stored in 200 L drums awaiting solidification in bitumen. The incinerator and a 50-ton hydraulic baler have provided treatment for a combined volume of about 1300 m 3 /a of solid low-level radioactive waste. This paper presents a review of the performance of the incinerator during its six years of operation. In addition to presenting operational experience, an assessment of the starved-air incineration technique will also be discussed

Assessment of the National Research Universal Reactor Proposed New Stack Sampling Probe Location for Compliance with ANSI/HPS N13.1-1999

Energy Technology Data Exchange (ETDEWEB)

Glissmeyer, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Antonio, Ernest J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-02-29

This document reports on a series of tests conducted to assess the proposed air sampling location for the National Research Universal reactor (NRU) complex exhaust stack, located in Chalk River, Ontario, Canada, with respect to the applicable criteria regarding the placement of an air sampling probe. Due to the age of the equipment in the existing monitoring system, and the increasing difficulty in acquiring replacement parts to maintain this equipment, a more up-to-date system is planned to replace the current effluent monitoring system, and a new monitoring location has been proposed. The new sampling probe should be located within the exhaust stack according to the criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream. The internal Pacific Northwest National Laboratory (PNNL) project for this task was 65167, Atomic Energy Canada Ltd. Chalk River Effluent Duct Flow Qualification. The testing described in this document was guided by the Test Plan: Testing of the NRU Stack Air Sampling Position (TP-STMON-032).

Controls on upper Campanian-Maastrichtian chalk deposition in the eastern Danish Basin

DEFF Research Database (Denmark)

Boussaha, Myriam; Thibault, Nicolas Rudolph; Anderskouv, Kresten

2017-01-01

% of the sediment. Sedimentation took place in deep water, below the photic zone and storm-wave base, and is characterized by decimetre to metre-scale variations in facies and trace fossil assemblages indicating repeated shifts in depositional environment. Integration of facies with published data on sea...... of accumulation rates and sea temperatures and is interpreted to represent a very broad set of deep water environmental conditions with an ample supply of calcareous nannofossil debris and intense bioturbation. Longer term shifts in deposition are best expressed by distribution of clay, flint and bioturbated...... micro-wackestone, bioturbated wackestone and laminated mudstone chalk facies, whereas the trace fossil assemblages appear less useful. The data set indicates overall shallowing over time with two distinctive events of clay influx to the basin during the late Campanian-earliest Maastrichtian and late...

Development of an Integrated Waste Plan for Chalk River Laboratories - 13376

International Nuclear Information System (INIS)

Jones, L.

2013-01-01

To further its Strategic Planning, the Atomic Energy of Canada Limited (AECL) required an effective approach to developing a fully integrated waste plan for its Chalk River Laboratories (CRL) site. Production of the first Integrated Waste Plan (IWP) for Chalk River was a substantial task involving representatives from each of the major internal stakeholders. Since then, a second revision has been produced and a third is underway. The IWP remains an Interim IWP until all gaps have been resolved and all pathways are at an acceptable level of detail. Full completion will involve a number of iterations, typically annually for up to six years. The end result of completing this process is a comprehensive document and supporting information that includes: - An Integrated Waste Plan document summarizing the entire waste management picture in one place; - Details of all the wastes required to be managed, including volume and timings by waste stream; - Detailed waste stream pathway maps for the whole life-cycle for each waste stream to be managed from pre-generation planning through to final disposition; and - Critical decision points, i.e. decisions that need to be made and timings by when they need to be made. A waste inventory has been constructed that serves as the master reference inventory of all waste that has been or is committed to be managed at CRL. In the past, only the waste that is in storage has been effectively captured, and future predictions of wastes requiring to be managed were not available in one place. The IWP has also provided a detailed baseline plan at the current level of refinement. Waste flow maps for all identified waste streams, for the full waste life cycle complete to disposition have been constructed. The maps identify areas requiring further development, and show the complexities and inter-relationships between waste streams. Knowledge of these inter-dependencies is necessary in order to perform effective options studies for enabling

Change in Biot's effective stress coefficient of chalk during pore collapse

DEFF Research Database (Denmark)

Alam, M. Monzurul; Fabricius, Ida Lykke

2013-01-01

the grains could also change during elastic deformation of the grains in a rock mechanics test. Diagenetic change in grain contact cement of chalk can be compared with stress-induced change in the laboratory. The change in porosity is studied with reference to the change in effective stress on grain contacts...... and porosity reduces at a slower rate. We noticed that presence of non carbonates and hydrocarbon could increase σ'm. During rock mechanics test in the lab, with increased applied stress, σ'm increases, Biot's effective stress coefficient shows a decreasing trend, while a minor porosity reduction was observed......Biot's effective stress coefficient (α) is a measure of how well grains in the rocks are connected with each other. The amount of contact cements between the grains determines the stiffness of rocks. Change in grain contact occurs during natural diagenesis of sedimentary rock. Contact between...

Contaminated groundwater characterization at the Chalk River Laboratories, Ontario, Canada

Energy Technology Data Exchange (ETDEWEB)

Schilk, A.J.; Robertson, D.E.; Thomas, C.W.; Lepel, E.A. [Pacific Northwest National Lab., Richland, WA (United States); Champ, D.R.; Killey, R.W.D.; Young, J.L.; Cooper, E.L. [Chalk River Labs., Chalk River, Ontario (Canada)

1993-03-01

The licensing requirements for the disposal of low-level radioactive waste (10 CFR 61) specify the performance objectives and technical requisites for federal and commercial land disposal facilities, the ultimate goal of which is to contain the buried wastes so that the general population is adequately protected from harmful exposure to any released radioactive materials. A major concern in the operation of existing and projected waste disposal sites is subterranean radionuclide transport by saturated or unsaturated flow, which could lead to the contamination of groundwater systems as well as uptake by the surrounding biosphere, thereby directly exposing the general public to such materials. Radionuclide transport in groundwater has been observed at numerous commercial and federal waste disposal sites [including several locations within the waste management area of Chalk River Laboratories (CRL)], yet the physico-chemical processes that lead to such migration are still not completely understood. In an attempt to assist in the characterization of these processes, an intensive study was initiated at CRL to identify and quantify the mobile radionuclide species originating from three separate disposal sites: (a) the Chemical Pit, which has received aqueous wastes containing various radioisotopes, acids, alkalis, complexing agents and salts since 1956, (b) the Reactor Pit, which has received low-level aqueous wastes from a reactor rod storage bay since 1956, and (c) the Waste Management Area C, a thirty-year-old series of trenches that contains contaminated solid wastes from CRL and various regional medical facilities. Water samples were drawn downgradient from each of the above sites and passed through a series of filters and ion-exchange resins to retain any particulate and dissolved or colloidal radionuclide species, which were subsequently identified and quantified via radiochemical separations and gamma spectroscopy. These groundwaters were also analyzed for anions

Magnetic field related mechanical tolerances for the proposed Chalk River superconducting heavy-ion cyclotron

International Nuclear Information System (INIS)

Heighway, E.A.; Chaplin, K.R.

1977-11-01

A four sector azimuthally varying field cyclotron with superconducting main coils has been proposed as a heavy-ion post-accelerator for the Chalk River MP Tandem van de Graaff. The radial profile of the average axial field will be variable using movable steel trim rods. The field errors due to coil, trim rod and flutter pole imperfections are calculated. Those considered are errors in the axial field, first and second azimuthal harmonic axial fields, transverse field and first azimuthal harmonic transverse field. Such fields induce phase slip, axial or radial coherent oscillations and can result in axial or radial beam instability. The allowed imperfections (tolerances) required to retain stability and maintain acceptably small coherent oscillation amplitudes are calculated. (author)

Optimization of Spore Forming Bacteria Flooding for Enhanced Oil Recovery in North Sea Chalk Reservoir

DEFF Research Database (Denmark)

Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna

2015-01-01

.2-3.8 cm) during bacteria injection. Further seawater flooding after three days shut in period showed that permeability gradually increased in the first two sections of the core and started to decrease in the third section of the core (3.8-6.3 cm). Complete plugging was never observed in our experiments.......Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focused on core flooding experiments to see microbial plugging and its effect on oil recovery. A pressure tapped core holder with pressure ports at 1.2 cm, 3.8 cm, and 6.3 cm from the inlet...

Integrating geophysical and hydrochemical borehole-log measurements to characterize the Chalk aquifer, Berkshire, United Kingdom

Science.gov (United States)

Schürch, Marc; Buckley, David

2002-09-01

Geophysical and hydrochemical borehole-logging techniques were integrated to characterize hydraulic and hydrogeochemical properties of the Chalk aquifer at boreholes in Berkshire, UK. The down-hole measurements were made to locate fissures in the chalk, their spatial extent between boreholes, and to determine the groundwater chemical quality of the water-bearing layers. The geophysical borehole logging methods used were caliper, focused resistivity, induction resistivity, gamma ray, fluid temperature, fluid electrical conductivity, impeller and heat-pulse flowmeter, together with borehole wall optical-imaging. A multiparameter data transmitter was used to measure groundwater temperature, electrical conductivity, dissolved oxygen, pH, and redox potential of the borehole fluid down-hole. High permeability developed at the Chalk Rock by groundwater circulation provides the major flow horizon at the Banterwick Barn study site and represents a conduit system that serves as an effective local hydraulic connection between the boreholes. The Chalk Rock includes several lithified solution-ridden layers, hardgrounds, which imply a gap in sedimentation possibly representing an unconformity. Lower groundwater temperature, high dissolved-oxygen content, and flowmeter evidence of preferential groundwater flow in the Chalk Rock indicated rapid groundwater circulation along this horizon. By repeating the logging at different times of the year under changing hydraulic conditions, other water-inflow horizons within the Chalk aquifer were recognized. Résumé. Des techniques géophysiques et hydrochimiques de diagraphies en forage ont été mises en oeuvre pour caractériser les propriétés hydrauliques et hydrogéochimiques de l'aquifère de la craie dans des forages du Berkshire (Grande-Bretagne). Les mesures en descente ont été faites pour localiser les fissures dans la craie et leur développement spatial entre forages, et pour déterminer la qualité de l'eau souterraine des

Productivity, facies and stable-isotope records of OAE2 (Cenomanian - Turonian) in the NW European epicontinental sea: from the English Chalk to North Sea black shales

Science.gov (United States)

Jarvis, Ian; Olde, Kate; Trabucho-Alexandre, João; Gröcke, Darren

2013-04-01

The Late Cretaceous (100.5 - 66.0 Ma) provides perhaps the best example of how the Earth System may function under long-term extreme greenhouse conditions. Rapidly rising global temperatures indicate that we are heading 'back to the Cretaceous' within a few hundred years, so a better understanding of this time interval is essential. The beginning of the Late Cretaceous was characterized by a period of rapidly rising eustatic sea level, the Cenomanian transgression, which flooded continental margins and established large areas of new epicontinental sea that accumulated thick sequences of pelagic and hemipelagic carbonate (chalk). Highest global temperatures were reached during the early part of the Turonian Stage (93.9 - 89.8 Ma). This period of dramatic palaeoenvironmental change was accompanied by one the largest perturbations of the global carbon cycle in the Mesozoic: Oceanic Anoxic Event 2 (OAE2), which was characterized by a 500 kyr episode of oceanic anoxia, widespread black shale deposition, biotic turnover, and a large global positive carbon stable-isotope excursion (2 - 6 ‰ ∂13C) recorded in marine carbonates and both marine and terrestrial organic matter. The Cenomanian-Turonian boundary interval exposed at Eastbourne, southern England, has become established as a European reference section for OAE2. Here, and elsewhere in Europe, the base of the ∂13C excursion is coincident with a marked facies change from rhythmically bedded grey chalks and marls, to a >8 m thick package of dark greenish-grey marl - the Plenus Marl. The termination of OAE2 occurs 6 m above, in a package of pale-yellow-weathering nodular chalks with prominent marl seams. Sediments are organic lean (10 wt%. The onshore equivalent in eastern England (the Black Band) is similarly organic-rich, as are comparable sections in northern Germany (e.g. Wunstorf), indicating likely fully anoxic episodes within some NW European basins. The exact stratigraphic equivalence between the onshore

US team measurements during the June 1987 experimental HT release at the Chalk River Nuclear Laboratories, Ontario, Canada

International Nuclear Information System (INIS)

Jalbert, R.A.; Murphy, C.E.

1988-01-01

In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of HT in the environment. The experiment involved a 30-minute release of 100 Ci of HT to the atmosphere at an elevation of one meter. The HTOHT ratios were shown to slowly increase downwind (/approximately/4 /times/ 10/sup /minus/5/ at 50 meters to almost 10/sup /minus/3 at 400 meters) as conversion of HT takes place. For several days after the release, HTO concentrations in the atmosphere remained elevated. Freeze-dried water from vegetation samples was found to be very low in HTO immediately after the release suggesting a very low direct uptake of HTO in air by vegetation. The tritiated water concentration increased during the first day, peaking during the second day (about 400 to 600 pCiml of water at 50 meters from the source) and decreasing by the end of the second day. The organically bound tritium continued to accumulate during the period following exposure (about 10 pCigm dry weight at 50 meters after two days). 4 refs., 6 figs., 2 tabs

Changes in Specific Surface as observed by NMR, caused by saturation of Chalk with porewater bearing divalent Ions

DEFF Research Database (Denmark)

Katika, Konstantina; Addassi, Mouadh; Alam, Mohammad Monzurul

2014-01-01

Nuclear Magnetic Resonance (NMR) spectrometry has proved to be a good technique for determining the petrophysical properties of reservoir rocks; such as porosity and pore size distribution. We investigated how pore water rich in divalent ions affect the NMR signal from chalk with two different de......-to-volume ratio of the pore space. The results of this work could benefit the ongoing study on the optimization of the water composition for Enhanced Oil Recovery (EOR) methods and shed light on how it can affect the mechanical and physical properties of the rock....

Ultralow-level measurement of organically-bound tritium in bioassay samples

International Nuclear Information System (INIS)

Kotzer, T.; Trivedi, A.; Waito, G.; Workman, W.

1998-12-01

An intercomparison study of urine samples having high levels (5 Bq·L -1 ) of organically-bound tritium (OBT) was conducted, in conjunction with the oxygen combustion-liquid scintillation counting (LSC) method, to evaluate the suitability and sensitivity of the 3 He-ingrowth mass spectrometry (MS) technique for OBT in bioassay samples. The study established that 3 He ingrowth-MS has the required sensitivity to measure ultralow levels of OBT-in-urine (∼0.1 Bq·L -1 ). Cumulative 24 h urine samples from a few members of the general population, living in the vicinity of the heavy-water research reactor facility at Chalk River Laboratories (CRL) at Chalk River, were collected and analyzed for tritiated water (HTO) and OBT. The participants were from Ottawa (200 km east), Deep River (10 km west) and an occasionally occupationally HTO-exposed worker at CRL. HTO-in-urine values were 6.5 Bq·L -1 for the Ottawa resident, 15.8 Bq·L -1 for the Deep River resident, and 1260 Bq·L -1 for the exposed worker. OBT-in-urine levels from these same individuals were 0.06 Bq·L -1 (Ottawa), 0.29 Bq·L -1 (Deep River), and 2.2 Bq·L -1 (exposed worker). With a model developed for calculating OBT dose fraction from the measured ratio of HTO to OBT in urine, we estimated that the dose arising from OBT in the body was about 26% of the total tritium dose for the Ottawa resident and 50% for the Deep River resident. The CRL individual had a 5% dose contribution from OBT, but had higher overall tritium dose due to frequent intakes of HTO. The study indicates that the bulk of the tritium dose to the population is the result of HTO intakes and not due to dietary intake of OBT. (author)

U.S. team measurements during the June 1987 experimental HT release at the Chalk River Nuclear Laboratories, Ontario, Canada

International Nuclear Information System (INIS)

Jalbert, R.A.; Murphy, C.E.

1988-01-01

In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of HT in the environment. The experiment involved a 30-minute release of 3.54 TBq (95.7 Ci) of HT to the atmosphere at an elevation of one meter. The HTO/HT ratios were shown to slowly increase downwind (-- 4 x 10/sup -5/ at 50 meters to almost 10/sup -3/ at 400 meters) as conversion of HT takes place. For several days after the release, HTO concentrations in the atmosphere remained elevated. Freeze-dried water from vegetation samples was found to be very low in HTO immediately after the release suggesting a very low direct uptake of HTO in air by vegetation. The free-HTO concentration in vegetation increased during the first day, peaking during the second day (about 1.5 - 3.0 x 10/sup 4/ Bq/L at 50 meters from the source) and decreasing by the end of the second day. The organically bound tritium continued to accumulate during the period following exposure (about 400 Bq/kg dry weight at 50 meters after two days)

Causes of death among long-term employees of Chalk River Laboratories, 1966-1989

International Nuclear Information System (INIS)

Werner, M.M.; Myers, D.K.

1990-11-01

Data on mortality among long-term employees of Chalk River Laboratories to 1989 December 31 are reported. The 1988 Hare report, entitled The Safety of Ontario's Nuclear Power Reactors, noted that there had been a steady rise in standardized mortality ratios (SMR) for cancer among these employees in the last three successive five-year periods from 1971-75 to 1981-85. None of the SMRs was significantly different from unity; however, the apparent trend could be indicative of the development of latent cancers. The present report was prepared to see if that increasing trend in cancer SMRs continued. In the years 1986-89, the SMR for cancer among long-term male employees was exceptionally low. The wide fluctuations seen in our data over time are likely anomalies arising from the small size of the study group rather than problems arising from radiation exposures on site

U–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada

International Nuclear Information System (INIS)

Neymark, L.A.; Peterman, Z.E.; Moscati, R.J.; Thivierge, R.H.

2013-01-01

Highlights: • AECL evaluates Chalk River Laboratories site as potential nuclear waste repository. • Isotope-geochemical data for rocks and fracture minerals at CRL site are reported. • Zircons from gneiss and granite yielded U–Pb ages of 1472 ± 14 and 1045 ± 6 Ma. • WR Rb–Sr and Pb–Pb systems do not show substantial large-scale isotopic mobility. • U-series and REE data do not support oxidizing conditions at depth in the past 1 Ma. - Abstract: As part of the Geologic Waste Management Facility feasibility study, Atomic Energy of Canada Ltd. (AECL) is evaluating the suitability of the Chalk River Laboratories (CRL) site in Ontario, situated in crystalline rock of the southwestern Grenville Province, for the possible development of an underground repository for low- and intermediate-level nuclear waste. This paper presents petrographic and trace element analyses, U–Pb zircon dating results, and Rb–Sr, U–Pb and U-series isotopic analyses of gneissic drill core samples from the deep CRG-series characterization boreholes at the CRL site. The main rock types intersected in the boreholes include hornblende–biotite (±pyroxene) gneisses of granitic to granodioritic composition, leucocratic granitic gneisses with sparse mafic minerals, and garnet-bearing gneisses with variable amounts of biotite and/or hornblende. The trace element data for whole-rock samples plot in the fields of within-plate, syn-collision, and volcanic arc-type granites in discrimination diagrams used for the tectonic interpretation of granitic rocks. Zircons separated from biotite gneiss and metagranite samples yielded SHRIMP-RG U–Pb ages of 1472 ± 14 (2σ) and 1045 ± 6 Ma, respectively, in very good agreement with widespread Early Mesoproterozoic plutonic ages and Ottawan orogeny ages in the Central Gneiss Belt. The Rb–Sr, U–Pb, and Pb–Pb whole-rock errorchron apparent ages of most of the CRL gneiss samples are consistent with zircon U–Pb age and do not indicate

Liquid chromatography in migration studies

International Nuclear Information System (INIS)

Carlsen, L.; Batsberg, W.

1982-01-01

Liquid chromatography ahs been suggested as a facile experimental technique to determine important physico-chemical properties, as permeability, porosity, dispersion-, diffusion-, and sorption charcteristics for geological material as chalk samples. The feasibility of the trechnique as a rapid method to evaluate the possible influence of changes in ground water composition on the migration behavior of radionuclides has been demonstrated

Proposed approach for bedrock characterization at Chalk River Nuclear Laboratories for waste disposal

International Nuclear Information System (INIS)

Heystee, R.J.; Dixon, D.F.

1985-07-01

Low- and intermediate-level wastes (L AND ILW) are produced at the Chalk River Nuclear Laboratories (CRNL) by the operation of reactors for nuclear research and development and by the production of radioisotopes. CRNL also manages L and ILW produced by Canadian research laboratories, universities, hospitals and some industries. An option that is being considered for the disposal of some of these wastes is to emplace them in a shallow rock cavity in fractured crystalline bedrock on the CRNL property. To design such a disposal facility and to evalute its long-term performance, data must be obtained on the geologic and hydrogeologic characteristics of the site. Over the past several years, a variety of airborne, ground surface and borehole geological, geophysical and/or hydrogeological methods have been used to acquire data on some rock mass discontinuities at CRNL. The techniques which are apparently more useful for acquiring these data are described and a proposed approach to site characterization for a shallow rock cavity at CRNL is outlined

Stability analysis of chalk sea cliffs using UAV photogrammetry

Science.gov (United States)

Barlow, John; Gilham, Jamie

2017-04-01

Cliff erosion and instability poses a significant hazard to communities and infrastructure located is coastal areas. We use point cloud and spectral data derived from close range digital photogrammetry to assess the stability of chalk sea cliffs located at Telscombe, UK. Data captured from an unmanned aerial vehicle (UAV) were used to generate dense point clouds for a 712 m section of cliff face which ranges from 20 to 49 m in height. Generated models fitted our ground control network within a standard error of 0.03 m. Structural features such as joints, bedding planes, and faults were manually mapped and are consistent with results from other studies that have been conducted using direct measurement in the field. Kinematic analysis of these data was used to identify the primary modes of failure at the site. Our results indicate that wedge failure is by far the most likely mode of slope instability. An analysis of sequential surveys taken from the summer of 2016 to the winter of 2017 indicate several large failures have occurred at the site. We establish the volume of failure through change detection between sequential data sets and use back analysis to determine the strength of shear surfaces for each failure. Our results show that data capture through UAV photogrammetry can provide useful information for slope stability analysis over long sections of cliff. The use of this technology offers significant benefits in equipment costs and field time over existing methods.

Investigation of the influence of sampling schemes on quantitative dynamic fluorescence imaging.

Science.gov (United States)

Dai, Yunpeng; Chen, Xueli; Yin, Jipeng; Wang, Guodong; Wang, Bo; Zhan, Yonghua; Nie, Yongzhan; Wu, Kaichun; Liang, Jimin

2018-04-01

Dynamic optical data from a series of sampling intervals can be used for quantitative analysis to obtain meaningful kinetic parameters of probe in vivo . The sampling schemes may affect the quantification results of dynamic fluorescence imaging. Here, we investigate the influence of different sampling schemes on the quantification of binding potential ( BP ) with theoretically simulated and experimentally measured data. Three groups of sampling schemes are investigated including the sampling starting point, sampling sparsity, and sampling uniformity. In the investigation of the influence of the sampling starting point, we further summarize two cases by considering the missing timing sequence between the probe injection and sampling starting time. Results show that the mean value of BP exhibits an obvious growth trend with an increase in the delay of the sampling starting point, and has a strong correlation with the sampling sparsity. The growth trend is much more obvious if throwing the missing timing sequence. The standard deviation of BP is inversely related to the sampling sparsity, and independent of the sampling uniformity and the delay of sampling starting time. Moreover, the mean value of BP obtained by uniform sampling is significantly higher than that by using the non-uniform sampling. Our results collectively suggest that a suitable sampling scheme can help compartmental modeling of dynamic fluorescence imaging provide more accurate results and simpler operations.

Delineating chalk sand distribution of Ekofisk formation using probabilistic neural network (PNN) and stepwise regression (SWR): Case study Danish North Sea field

Science.gov (United States)

Haris, A.; Nafian, M.; Riyanto, A.

2017-07-01

Danish North Sea Fields consist of several formations (Ekofisk, Tor, and Cromer Knoll) that was started from the age of Paleocene to Miocene. In this study, the integration of seismic and well log data set is carried out to determine the chalk sand distribution in the Danish North Sea field. The integration of seismic and well log data set is performed by using the seismic inversion analysis and seismic multi-attribute. The seismic inversion algorithm, which is used to derive acoustic impedance (AI), is model-based technique. The derived AI is then used as external attributes for the input of multi-attribute analysis. Moreover, the multi-attribute analysis is used to generate the linear and non-linear transformation of among well log properties. In the case of the linear model, selected transformation is conducted by weighting step-wise linear regression (SWR), while for the non-linear model is performed by using probabilistic neural networks (PNN). The estimated porosity, which is resulted by PNN shows better suited to the well log data compared with the results of SWR. This result can be understood since PNN perform non-linear regression so that the relationship between the attribute data and predicted log data can be optimized. The distribution of chalk sand has been successfully identified and characterized by porosity value ranging from 23% up to 30%.

Relativistic electron influence on sanitary-model microorganisms and antibiotics in model samples

International Nuclear Information System (INIS)

Antipov, V.S.; Berezhna, I.V.; Kovpik, O.F.; Babych, E.M.; Voliansky, Yu.L.; Sklar, N.I.

2004-01-01

A series of the investigations of the electron beam influence on sanitary-model test cultures and antibiotics in model solutions has been carried out. For each of the test objects, the authors have found the boundary doses of the absorbed radiation. The higher doses cause the sharp increase in the bactericidal influence, which becomes complete. The sanitary-bactericidal indices of the water samples remain sable during 6 days. The samples of antibiotics in various concentrations (from 100 UA) have been irradiated. It is proved that the substratum processing by the beam (in the regimes 30 kGy) causes diminution and complete neutralization of the antibacterial activity in all probes of the samples

An overview of the waste characterization program at Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Csullog, G.W.; Hardy, D.G.

1988-01-01

In the last five years, Chalk River Nuclear Laboratories (CRNL) placed 17,000 m 3 of wastes into storage (excluding contaminated soil and fill). Almost half of the waste was generated off-site. CRNL is now developing IRUS, an Intrusion Resistant Underground Structure, and the IST, an Improved Sand Trench, to replace storage with safe, permanent disposal. IRUS will be used to dispose of wastes with radiologically hazardous lifetimes between 150 and 500 years duration and the IST will be used for wastes with radiologically hazardous lifetimes of less than 150 years. A comprehensive Waste Characterization Program (WCP) is in place to support disposal projects. The WCP is responsible for (1) specifying the manifests for waste shipments; (2) developing and maintaining central databases for waste inventories and analytical data; and (3) developing the technologies and procedures to characterize the radiological and the physical/chemical properties of wastes. WCP work is being performed under the umbrella of a newly developed waste management quality assurance (QA) program. This paper gives an overview of the WCP with an emphasis on the requirements for determining radionuclide inventories in wastes, for implementing record-keeping systems and for maintaining a QA program for disposal operations

Air exposure and sample storage time influence on hydrogen release from tungsten

Energy Technology Data Exchange (ETDEWEB)

Moshkunov, K.A., E-mail: moshkunov@gmail.co [National Research Nuclear University ' MEPhI' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Schmid, K.; Mayer, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Kurnaev, V.A.; Gasparyan, Yu.M. [National Research Nuclear University ' MEPhI' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation)

2010-09-30

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D{sub 2}O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of {approx}300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

Air exposure and sample storage time influence on hydrogen release from tungsten

International Nuclear Information System (INIS)

Moshkunov, K.A.; Schmid, K.; Mayer, M.; Kurnaev, V.A.; Gasparyan, Yu.M.

2010-01-01

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D 2 O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of ∼300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

Air exposure and sample storage time influence on hydrogen release from tungsten

Science.gov (United States)

Moshkunov, K. A.; Schmid, K.; Mayer, M.; Kurnaev, V. A.; Gasparyan, Yu. M.

2010-09-01

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D 2O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of ˜300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

Non-destructive identification of micrometer-scale minerals and their position within a bulk sample

DEFF Research Database (Denmark)

Sørensen, Henning O.; Hakim, Sepide S.; Pedersen, Stefan

2012-01-01

. Crushing or disintegrating a sample annihilates any possibility for gathering information from the texture of the porous media or the mineral assemblage close to the grains in question. A new method using three-dimensional X-ray diffraction (3DXRD) microscopy can be successfully applied to natural...... materials. We combined X-ray microtomography (XMT) and 3DXRD to investigate a sample of very fine-grained chalk containing fracture minerals. The XMT technique provides three-dimensional images of the particles and pore structure at very high resolution (350 nm voxel dimension) on samples less than 500 μm......Using the conventional techniques of mineralogy, it has been a challenge to determine mineral identity, crystal orientation and spatial position of micrometer-sized crystals that are embedded in a rock, sediment or soil. Traditionally, the individual grains must be extracted and analyzed separately...

Towards a representative periphytic diatom sample

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available The need to acquire a representative periphytic diatom sample for river water quality monitoring has been recognised in the development of existing diatom indices, important in the development and employment of diatom monitoring tools for the Water Framework Directive. In this study, a nested design with replication is employed to investigate the magnitude of variation in diatom biomass, composition and Trophic Diatom Index at varying scales within a small chalk river. The study shows that the use of artificial substrates may not result in diatom communities that are typical of the surrounding natural substrates. Periphytic diatom biomass and composition varies between artificial and natural substrates, riffles and glides and between two stretches of the river channel. The study also highlights the existence of high variation in diatom frustule frequency and biovolume at the individual replicate scale which may have implications for the use of diatoms in routine monitoring.

Influence of volume of sample processed on detection of Chlamydia trachomatis in urogenital samples by PCR

NARCIS (Netherlands)

Goessens, W H; Kluytmans, J A; den Toom, N; van Rijsoort-Vos, T H; Niesters, B G; Stolz, E; Verbrugh, H A; Quint, W G

In the present study, it was demonstrated that the sensitivity of the PCR for the detection of Chlamydia trachomatis is influenced by the volume of the clinical sample which is processed in the PCR. An adequate sensitivity for PCR was established by processing at least 4%, i.e., 80 microliters, of

Uranium series geochemistry in aquifers: quantification of transport mechanisms of uranium and daughter products: the chalk aquifer (Champagne, France)

International Nuclear Information System (INIS)

Hubert, A.

2005-09-01

With the increase of contaminant flux of radionuclides in surface environment (soil, river, aquifer...), there is a need to understand and model the processes that control the distribution of uranium and its daughter products during transport within aquifers. We have used U-series disequilibria as an analogue for the transport of uranium and its daughter products in aquifer to understand such mechanisms. The measurements of uranium ( 234 U et 238 U), thorium ( 230 Th et 232 Th), 226 Ra and 222 Rn isotopes in the solid and liquid phases of the chalk aquifer in Champagne (East of France) allows us to understand the processes responsible for fractionation within the uranium decay chain. Fractionations are induced by physical and chemical properties of the elements (leaching, adsorption) but also by radioactive properties (recoil effect during α-decay). For the first time a comprehensive sampling of the solid phase has been performed, allowing quantifying mechanisms responsible for the long term evolution of the aquifer. A non steady state 1D model has been developed which takes into account leaching, adsorption processes as well as radioactive filiation and α-recoil effect. Retardation coefficients have been calculated for uranium, thorium and radium. The aquifer is characterised by a double porosity, and the contribution of fracture and matrix porosity on the water/rock interaction processes has been estimated. (author)

Influences of different sample preparation methods on tooth enamel ESR signals

International Nuclear Information System (INIS)

Zhang Wenyi; Jiao Ling; Zhang Liang'an; Pan Zhihong; Zeng Hongyu

2005-01-01

Objective: To study the influences of different sample preparation methods on tooth enamel ESR signals in order to reduce the effect of dentine on their sensitivities to radiation. Methods: The enamel was separated from dentine of non-irradiated adult teeth by mechanical, chemical, or both methods. The samples of different preparations were scanned by an ESR spectrometer before and after irradiation. Results: The response of ESR signals of samples prepared with different methods to radiation dose was significantly different. Conclusion: The selection of sample preparation method is very important for dose reconstruction by tooth enamel ESR dosimetry, especially in the low dose range. (authors)

Influence of short-term sampling parameters on the uncertainty of the Lden environmental noise indicator

International Nuclear Information System (INIS)

Mateus, M; Carrilho, J Dias; Da Silva, M Gameiro

2015-01-01

The present study deals with the influence of the sampling parameters on the uncertainty of noise equivalent level in environmental noise measurements. The study has been carried out through the test of different sampling strategies doing resampling trials over continuous monitoring noise files obtained previously in an urban location in the city of Coimbra, in Portugal. On short term measurements, not only the duration of the sampling episodes but also its number have influence on the uncertainty of the result. This influence is higher for the time periods where sound levels suffer a greater variation, such as during the night period. In this period, in case both parameters (duration and number of sampling episodes) are not carefully selected, the uncertainty level can reach too high values contributing to a loss of precision of the measurements. With the obtained data it was investigated the sampling parameters influence on the long term noise indicator uncertainty, calculated according the Draft 1st CD ISO 1996-2:2012 proposed method. It has been verified that this method allows the possibility of defining a general methodology which enables the setting of the parameters once the precision level is fixed. For the three reference periods defined for environmental noise (day, evening and night), it was possible to derive a two variable power law representing the uncertainty of the determined values as a function of the two sampling parameters: duration of sampling episode and number of episodes

Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Annual report, March 1996--March 1997

Energy Technology Data Exchange (ETDEWEB)

Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Groshong, R.H.

1997-08-01

Gilbertown Field is the oldest oil field in Alabama and produces oil from chalk of the Upper Cretaceous Selma Group and from sandstone of the Eutaw Formation along the southern margin of the Gilbertown fault system. Most of the field has been in primary recovery since establishment, but production has declined to marginally economic levels. This investigation applies advanced geologic concepts designed to aid implementation of improved recovery programs. The Gilbertown fault system is detached at the base of Jurassic salt. The fault system began forming as a half graben and evolved in to a full graben by the Late Cretaceous. Conventional trapping mechanisms are effective in Eutaw sandstone, whereas oil in Selma chalk is trapped in faults and fault-related fractures. Burial modeling establishes that the subsidence history of the Gilbertown area is typical of extensional basins and includes a major component of sediment loading and compaction. Surface mapping and fracture analysis indicate that faults offset strata as young as Miocene and that joints may be related to regional uplift postdating fault movement. Preliminary balanced structural models of the Gilbertown fault system indicate that synsedimentary growth factors need to be incorporated into the basic equations of area balance to model strain and predict fractures in Selma and Eutaw reservoirs.

Importance of small fishes and invasive crayfish in otter Lutra lutra diet in an English chalk stream

Directory of Open Access Journals (Sweden)

Britton J. Robert

2017-01-01

Full Text Available The diet composition of the European otter Lutra lutra was assessed using spraint analysis in the Hampshire Avon, a lowland chalk stream in Southern England, over an 18-month period. Small cyprinid fishes were the main prey item taken in all seasons, with bullhead Cottus gobio and stone loach Barbatula barbatula also important; there were relatively few larger fishes of interest to fisheries found. There were significant seasonal differences in diet composition by season, with signal crayfish Pacifastacus leniusculus only being prominent prey items in warmer months and amphibians in winter, revealing that non-fish resources were seasonally important dietary components. Reconstructed body lengths of prey revealed the only species present in diet >350 mm was pike Esox lucius. These dietary data thus provide important information for informing conservation conflicts between otters and fishery interests.

Concentration of mercury in wheat samples stored with mercury tablets as preservative

International Nuclear Information System (INIS)

Lalit, B.Y.; Ramachandran, T.V.

1977-01-01

Tablets consisting of mercury in the form of a dull grey powder made by triturating mercury with chalk and sugar are used in Indian household for storing food-grains. The contamination of wheat samples by mercury, when stored with mercury tablets for period of upto four years has been assessed by using non-destructive neutron activation analysis. The details of the analytical procedure used have also been briefly described. The concentration of mercury in wheat increases with storage period. Loss of weight of mercury tablet is proportional to the storage period to a first approximation. In the present experiment, the average weight loss at the and end of first year was 0.009716 g corresponding to 6 ppm in wheat. (T.G.)

Predictors of Citation Rate in Psychology: Inconclusive Influence of Effect and Sample Size.

Science.gov (United States)

Hanel, Paul H P; Haase, Jennifer

2017-01-01

In the present article, we investigate predictors of how often a scientific article is cited. Specifically, we focus on the influence of two often neglected predictors of citation rate: effect size and sample size, using samples from two psychological topical areas. Both can be considered as indicators of the importance of an article and post hoc (or observed) statistical power, and should, especially in applied fields, predict citation rates. In Study 1, effect size did not have an influence on citation rates across a topical area, both with and without controlling for numerous variables that have been previously linked to citation rates. In contrast, sample size predicted citation rates, but only while controlling for other variables. In Study 2, sample and partly effect sizes predicted citation rates, indicating that the relations vary even between scientific topical areas. Statistically significant results had more citations in Study 2 but not in Study 1. The results indicate that the importance (or power) of scientific findings may not be as strongly related to citation rate as is generally assumed.

Radon levels in dwellings in chalk terrain. Development and analysis of distributional and causal models

International Nuclear Information System (INIS)

Killip, Ian Richmond

2002-01-01

This thesis investigates the range, distribution and causes of high radon levels in dwellings in the Brighton area of Southeast England. Indoor radon levels were measured in more than 1000 homes. The results show that high radon levels can arise in an area previously considered to offer low radon potential from local geological sources. Climate and building-related factors were found to affect significantly the radon levels in dwellings. Multiple regression was used to determine the influence of the various factors on indoor radon levels and an empirical model develop to predict indoor radon levels. The radon hazard, independent of building-related effects, was determined for each surveyed location by adjusting the radon measurement to that expected on the ground floor of a 'model' dwelling. This standardised set of radon levels was entered into a geographical information system (GIS) and related to surface geology. The geometric mean radon level for each lithological unit was plotted to produce a radon hazard map for the area. The highest radon levels were found to be associated with the youngest Chalk Formations, particularly where they meet overlying Tertiary deposits, and with Clay-with-Flints Quaternary deposits in the area. The results were also converted to the radon activity equivalent to that expected from the NRPB's standard dual-detector dwelling survey method and analysed by lognormal modelling to estimate the proportion of dwellings likely to exceed the UK Action Level of 200 Bq/m 3 for each lithological unit. The likely percentages of dwellings affected by radon thus obtained were mapped to lithological boundaries to produce a radon potential map. The radon hazard map and the empirical radon model facilitate the prediction of radon levels in dwellings of comparable construction and above similar geology and should further the understanding of the behaviour of radon gas in buildings to allow indoor radon concentrations to be controlled. The radon

AECL'S approach to managing long term liabilities at Chalk River Laboratories. Annex II

International Nuclear Information System (INIS)

Audet, M.C.

2006-01-01

Chalk River Laboratories (CRL) is a large nuclear research and development/ industrial site operated by Atomic Energy of Canada Limited (AECL). Construction of the site started in 1944, and it now includes over 100 buildings/facilities operating in various nuclear fields. A well developed decommissioning programme exists at CRL, with progress being made on decommissioning older redundant buildings, in parallel with ongoing site operations and development. The decommissioning programme is predicated on the assumption that the current nuclear operations will continue over a 100 year operating period, but with a decline towards the end of the period. Although decommissioning and remediation work will be carried out throughout the operational period, residual levels of activity remaining in a few areas will require institutional control (IC) for an assumed period of 300 years. The intention is to complete all necessary active remediation work before the start of the IC period and thereafter rely only on passive means to reduce residual contamination to levels that do not require IC measures. The latter include environmental monitoring, active and passive controls to prevent intrusion, and management controls to prohibit access or development. A formal information and records management programme at CRL has been initiated. (author)

A review of sample preparation and its influence on pH determination in concrete samples

International Nuclear Information System (INIS)

Manso, S.; Aguado, A.

2017-01-01

If we are to monitor the chemical processes in cementitious materials, then pH assays in the pore solutions of cement pastes, mortars, and concretes are of key importance. However, there is no standard method that regulates the sample-preparation method for pH determination. The state-of-the-art of different methods for pH determination in cementitious materials is presented in this paper and the influence of sample preparation in each case. Moreover, an experimental campaign compares three different techniques for pH determination. Its results contribute to establishing a basic criterion to help researchers select the most suitable method, depending on the purpose of the research. A simple tool is described for selecting the easiest and the most economic pH determination method, depending on the objective; especially for researchers and those with limited experience in this field.

Influence of thermal treatments on radiocarbon dating of groundwater samples

Science.gov (United States)

Stanciu, Iuliana Madalina; Sava, Tiberiu Bogdan; Pacesila, Doru Gheorghe; Gaza, Oana; Simion, Corina Anca; Stefan, Bianca Maria; Sava, Gabriela Odilia; Ghita, Dan Gabriel; Mosu, Vasile

2017-06-01

Radiocarbon measurements of dissolved inorganic carbon (DIC) in water provides information about the formation of oceanic circulation of the water volumes, the hydrogeological systems, and also valuable information can be gained about the aquifer storage and the degree of containment relative to the surface waters. Radiocarbon dating refers to the determination of small quantities of the naturally occurring carbon 14 in the water, which can be integrated in the groundwater mass through the gaseous CO2, carbonaceous deposits dissolved by water and organic remains. The aim of this study is to investigate the influence of the temperature and pressure over the amount of each isotope of carbon during the sample preparation stage. The first step was to evaporate several underground water samples at 65°C under different conditions until the carbonates were obtained, then the CO2 was extracted with orto-phosphoric acid and transformed to graphite. The second step was to obtain graphite from an untreated water sample. Finally, the samples were measured with the 1MV Cockcroft-Walton Tandetron Accelerator by Accelerator Mass Spectrometry.

A review of sample preparation and its influence on pH determination in concrete samples

Directory of Open Access Journals (Sweden)

S. Manso

2017-01-01

Full Text Available If we are to monitor the chemical processes in cementitious materials, then pH assays in the pore solutions of cement pastes, mortars, and concretes are of key importance. However, there is no standard method that regulates the sample-preparation method for pH determination. The state-of-the-art of different methods for pH determination in cementitious materials is presented in this paper and the influence of sample preparation in each case. Moreover, an experimental campaign compares three different techniques for pH determination. Its results contribute to establishing a basic criterion to help researchers select the most suitable method, depending on the purpose of the research. A simple tool is described for selecting the easiest and the most economic pH determination method, depending on the objective; especially for researchers and those with limited experience in this field.

Concentration of mercury in wheat samples stored with mercury tablets as preservative. [Neutrons

Energy Technology Data Exchange (ETDEWEB)

Lalit, B Y; Ramachandran, T V [Bhabha Atomic Research Centre, Bombay (India). Air Monitoring Section

1977-01-01

Tablets consisting of mercury in the form of a dull grey powder made by triturating mercury with chalk and sugar are used in Indian household for storing food-grains. The contamination of wheat samples by mercury, when stored with mercury tablets for period of upto four years has been assessed by using non-destructive neutron activation analysis. The details of the analytical procedure used have also been briefly described. The concentration of mercury in wheat increases with storage period. Loss of weight of mercury tablet is proportional to the storage period to a first approximation. In the present experiment, the average weight loss at the and end of first year was 0.009716 g corresponding to 6 ppm in wheat.

The TAC of porcelain samples and its influence on TL dating

International Nuclear Information System (INIS)

Leung, P.L.; Stokes, M.J.; Xia Junding; Wang Weida

1997-01-01

The thermal activation characteristics of porcelain slice samples for pre-dose dating were obtained by using the multiple activation method. The influence of activation temperature on TL dating was also studied. The results show that choosing a temperature corresponding to the maximum sensitivity on the TAC curve as the activation temperature is very important in the multiple activation method

The influence of adhesive joint characteristics of the bonded samples of PUR-foam

Directory of Open Access Journals (Sweden)

Josef Pacovský

2011-01-01

Full Text Available Upholstered chairs and upholstered furniture in general, is largely produced primarily using PUR-foams, and it largely in the form of gluing several types of foam and himself on a firm surface - usually plywood or the agglomerated material – for the qualitative increase of upholstered furniture (including seating. Work deals with properties of the bond in connection with the influence on the final properties of the finished product, or even a change of functional properties in use over time. This work deals with: The influence of the characteristics of the adhesive used on samples bonded polyurethane foams. This work deals with properties of the bond in connection with an influence on the final properties of the finished product, or changes in functional properties when used at the time. The work is focused on: Effect of glue applied to the characteristics of the bonded samples of PUR foam. To determine the effects observed were used as the basis for the methodology based on the standard EN 1957, which was further modified as necessary. The results of the tests and conclusions can be stated that the incidence of bonded joints, ultimately, has a negligible effect on the resulting observed characteristics and therefore can cut and paste samples of smaller sizes into larger blocks without a fundamental change of the original features.

Tritium behavior on a cultivated plot in the 1994 chronic HT release experiment at Chalk River

International Nuclear Information System (INIS)

Noguchi, H.; Yokoyama, S.; Kinouchi, N.; Murata, M.; Amano, H.; Atarashi, M.; Ichimasa, Y.; Ichimasa, M.

1995-01-01

The behavior of HT and HTO in air and surface soil has been studied extensively in the chronic HT release experiment carried out at Chalk River during the summer of 1994. HTO concentrations in air moisture and soil water collected in a cultivated plot showed similar time-variations, increasing rapidly during the first and second days and becoming gradual after the first 3-4 days. The air HTO concentration decreased during and following rainfall but recovered within a day. The rainfall reduced the HTO concentrations in ridge soil water but little in furrows. Time histories of HTO concentrations in air moisture and soil water suggest that the system was near steady-state within a continuous HT release period of 12 days, in spite of the presence of rain during the period. The air HTO concentrations on clear days showed diurnal cycles that were higher during daytime than at night. The experimental field had a very complex soil regime with respect to HT deposits. The deposits to soil surface varied depending on soil conditions. 12 refs., 5 figs

Pre-operational HTO/HT surveys in the vicinity of the Chalk River Laboratories tritium extraction plant

International Nuclear Information System (INIS)

Workman, W.J.G.; Brown, R.M.

1993-08-01

Surveys of the concentrations of HT and HTO in the atmosphere downwind of the Chalk River Laboratories reactor facilities were carried out in 1986 November, and in 1989 March, April and September under different conditions of air temperature, wind direction, and snow or vegetative cover. HT usually amounted to 1-5% of total tritium, but values up to 20% were observed, probably resulting from preferential removal of HTO. In all of the surveys, the greater persistence in the atmosphere of HT than of HTO was evident. The existing levels of HT are such that they will not be augmented significantly by chronic releases from the Tritium Extraction Plant (TEP) when it comes into operation. Hence, operation of the TEP will not facilitate studies of the environmental behaviour of chronically released HT. However, longer term studies of the distribution of HT from the existing facilities would be worthwhile. Soil and vegetation HTO levels in the study area are reported. Further studies of the distribution of tritium between the air, soil and vegetation in areas subjected to chronic exposure would be valuable

Impact of microstructure evolution on the difference between geometric and reactive surface areas in natural chalk

Science.gov (United States)

Yang, Y.; Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

2018-05-01

The coupling between flow and mineral dissolution drives the evolution of many natural and engineered flow systems. Pore surface changes as microstructure evolves but this transient behaviour has traditionally been difficult to model. We combined a reactor network model with experimental, greyscale tomography data to establish the morphological grounds for differences among geometric, reactive and apparent surface areas in dissolving chalk. This approach allowed us to study the effects of initial geometry and macroscopic flow rate independently. The simulations showed that geometric surface, which represents a form of local transport heterogeneity, increases in an imposed flow field, even when the porous structure is chemically homogeneous. Hence, the fluid-reaction coupling leads to solid channelisation, which further results in fluid focusing and an increase in geometric surface area. Fluid focusing decreases the area of reactive surface and the residence time of reactant, both contribute to the over-normalisation of reaction rate. In addition, the growing and merging of microchannels, near the fluid entrance, contribute to the macroscopic, fast initial dissolution rate of rocks.

Mortality study of Canadian military personnel exposed to radiation: atomic test blasts and Chalk River nuclear reactor clean-ups, 1950's

International Nuclear Information System (INIS)

Raman, S.; Dulberg, C.S.; Spasoff, R.A.

1984-08-01

This report describes a historical cohort study of the group of Canadian military personnel exposed to radiation in the 1950s at atomic bomb test blasts in the U.S. and Australia, and at clean-up operations at the Chalk River Nuclear Laboratories. Overall and cause-specific mortality in the exposed group was compared to that of the control cohort of unexposed military personnel, matched on age, service, rank and trade. Analyses indicated no elevation in the exposed cohort, in overall or cause-specific mortality due to diseases associated with radiation. Since this study was restricted to an investigation of mortality, we must stress that we cannot generalize these results or conclusions to current morbidity experienced by the exposed cohort

Influence of sample thickness on fracture behaviour of polyketone and a polyketone-rubber blend

NARCIS (Netherlands)

Zuiderduin, W.C.J.; Huetink, Han; Vlasveld, D.P.N.; Gaymans, R.J.

2005-01-01

The influence of sample thickness on the fracture behaviour of an aliphatic polyketone and a blend of this polymer and 10 wt% core–shell rubber was studied. The sample thickness was varied from 0.1 to 8 mm. The skin morphology was studied by SEM. The fracture behaviour was studied on single edge

The role of microbial community composition and groundwater chemistry in determining isoproturon degradation potential in UK aquifers.

Science.gov (United States)

Johnson, Andrew; Llewellyn, Neville; Smith, Jennifer; van der Gast, Christopher; Lilley, Andrew; Singer, Andrew; Thompson, Ian

2004-07-01

The community response of indigenous sandstone, chalk and limestone groundwater microorganisms to the addition of the commonly used herbicide isoproturon was examined. The addition of 100 microg l(-1) isoproturon generally caused an increase in species diversity determined by chemotaxonomic analysis (fatty methyl ester analysis) of isolates resulting from incubation of cultures at 18 degrees C for 4 days. Amongst the groundwater samples to which isoproturon was added, isoproturon degradation rates were correlated with increasing dominance of a few species. However, the changes in community profile associated with isoproturon degradation varied from site to site. Repeated sub-culturing with 100 microg l(-1) isoproturon and sterile groundwater was carried out to examine whether this level of pesticide could exert a selection pressure, and hence stimulate more rapid degradation. Significantly increased degradation was observed in a groundwater sample from the chalk, but not in sandstone, or limestone samples. The addition of filter-sterilised sandstone groundwater to bacteria on filter paper from slow degrading limestone sites significantly improved their degrading performance. The addition of filter-sterilised limestone groundwater to the sandstone bacteria reduced their degradation rate only slightly. The data suggested that the nature of the indigenous community does influence pesticide degradation in groundwater, but that the groundwater chemistry may also play a role.

Endophytic bacterial community of grapevine leaves influenced by sampling date and phytoplasma infection process.

Science.gov (United States)

Bulgari, Daniela; Casati, Paola; Quaglino, Fabio; Bianco, Piero A

2014-07-21

Endophytic bacteria benefit host plant directly or indirectly, e.g. by biocontrol of the pathogens. Up to now, their interactions with the host and with other microorganisms are poorly understood. Consequently, a crucial step for improving the knowledge of those relationships is to determine if pathogens or plant growing season influence endophytic bacterial diversity and dynamic. Four healthy, four phytoplasma diseased and four recovered (symptomatic plants that spontaneously regain a healthy condition) grapevine plants were sampled monthly from June to October 2010 in a vineyard in north-western Italy. Metagenomic DNA was extracted from sterilized leaves and the endophytic bacterial community dynamic and diversity were analyzed by taxon specific real-time PCR, Length-Heterogeneity PCR and genus-specific PCR. These analyses revealed that both sampling date and phytoplasma infection influenced the endophytic bacterial composition. Interestingly, in June, when the plants are symptomless and the pathogen is undetectable (i) the endophytic bacterial community associated with diseased grapevines was different from those in the other sampling dates, when the phytoplasmas are detectable inside samples; (ii) the microbial community associated with recovered plants differs from that living inside healthy and diseased plants. Interestingly, LH-PCR database identified bacteria previously reported as biocontrol agents in the examined grapevines. Of these, Burkholderia, Methylobacterium and Pantoea dynamic was influenced by the phytoplasma infection process and seasonality. Results indicated that endophytic bacterial community composition in grapevine is correlated to both phytoplasma infection and sampling date. For the first time, data underlined that, in diseased plants, the pathogen infection process can decrease the impact of seasonality on community dynamic. Moreover, based on experimental evidences, it was reasonable to hypothesize that after recovery the restructured

Assessment of the influence of different sample processing and cold storage duration on plant free proline content analyses.

Science.gov (United States)

Teklić, Tihana; Spoljarević, Marija; Stanisavljević, Aleksandar; Lisjak, Miroslav; Vinković, Tomislav; Parađiković, Nada; Andrić, Luka; Hancock, John T

2010-01-01

A method which is widely accepted for the analysis of free proline content in plant tissues is based on the use of 3% sulfosalicylic acid as an extractant, followed by spectrophotometric quantification of a proline-ninhydrin complex in toluene. However, sample preparation and storage may influence the proline actually measured. This may give misleading or difficult to compare data. To evaluate free proline levels fresh and frozen strawberry (Fragaria × ananassa Duch.) leaves and soybean [Glycine max (L.) Merr.] hypocotyl tissues were used. These were ground with or without liquid nitrogen and proline extracted with sulfosalicylic acid. A particular focus was the influence of plant sample cold storage duration (1, 4 and 12 weeks at -20°C) on tissue proline levels measured. The free proline content analyses, carried out in leaves of Fragaria × ananassa Duch. as well as in hypocotyls of Glycine max (L.) Merr., showed a significant influence of the sample preparation method and cold storage period. Long-term storage of up to 12 weeks at -20°C led to a significant increase in the measured proline in all samples analysed. The observed changes in proline content in plant tissue samples stored at -20°C indicate the likelihood of the over-estimation of the proline content if the proline analyses are delayed. Plant sample processing and cold storage duration seem to have an important influence on results of proline analyses. Therefore it is recommended that samples should be ground fresh and analysed immediately. Copyright © 2010 John Wiley & Sons, Ltd.

Influence of Freezing and Storage Procedure on Human Urine Samples in NMR-Based Metabolomics

OpenAIRE

Rist, Manuela; Muhle-Goll, Claudia; Görling, Benjamin; Bub, Achim; Heissler, Stefan; Watzl, Bernhard; Luy, Burkhard

2013-01-01

It is consensus in the metabolomics community that standardized protocols should be followed for sample handling, storage and analysis, as it is of utmost importance to maintain constant measurement conditions to identify subtle biological differences. The aim of this work, therefore, was to systematically investigate the influence of freezing procedures and storage temperatures and their effect on NMR spectra as a potentially disturbing aspect for NMR-based metabolomics studies. Urine sample...

INFLUENCE OF STORING AND TEMPERATURE ON RHEOLOGIC AND THERMOPHYSICAL PROPERTIES OF WHISKY SAMPLES

Directory of Open Access Journals (Sweden)

Peter Hlavac

2013-09-01

Full Text Available Temperature and storing time can be included between the most significant parameters that influence physical properties of food. This article deals with selected rheologic and thermophysical properties of alcohol drink whisky. Our research was oriented on measuring of rheologic and thermophysical characteristics of whisky. There were measured two types of whisky Grant s and Jim Beam from two different producers, both samples had 40 percent of alcohol content. During the experiments were analyzed rheologic parameters as dynamic viscosity, kinematic viscosity and fluidity and thermophysical parameters as thermal conductivity, thermal diffusivity and volume specific heat. Selected parameters were measured in temperature range 5 to 27 C. Measurements were done on whisky samples in different days during the storage. Measuring of dynamic viscosity was performed by digital rotational viscometer Anton Paar. Principle of measuring is based on dependency of sample resistance against the probe rotation. Density of whisky samples was determined by pycnometric method. Average density at given temperature along with dynamic viscosity value was used at calculation of kinematic viscosity and fluidity was also determined. Measuring of thermophysical parameters was performed by instrument Isomet 2104 Measurement by Isomet is based on analysis of the temperature response of the measured sample to heat flow impulses. Relations of rheologic and thermophysical parameters to the temperature were made and influence of storing time was discussed. From obtained results is clear that dynamic and kinematic viscosity is decreasing exponentially with temperature and fluidity has increasing exponential progress. We found out that both whisky samples had at the beginning and after one week of storage very similar values of rheologic parameters. Very small difference in rheologic parameters of whisky samples was found after two weeks of storing. Values of dynamic and kinematic

Chemosorption sampling and analysis of formaldehyde in air. Influence on recovery during the simultaneous sampling of formaldehyde, phenol, furfural and furfuryl alcohol

Energy Technology Data Exchange (ETDEWEB)

Andersson, K.; Hallgren, C.; Levin, J.O.; Nilsson, C.A.

1981-12-01

A method based on trapping formaldehyde on a 2,4-dinitrodinitrophenylhydrazine-coated porous polymer (Amberlite XAD-2) was evaluated for air sampling in occupational environments. The aldehyde is converted to its 2,4-dinitrophenylhydrazone on the adsorbent. The influence of some organic compounds which often occur together with formaldehyde-furfural, phenol and furfuryl alcohol--was studied. The results show that the method allows the sampling of formaldehyde in the range 0.01--1.0 mg/m3 of air, based on a 3-1 (15 min) sample and a coating of 1%. Furfural, phenol, and furfuryl alcohol do not interfere and may be conveniently sampled at the same time. Formaldehyde and furfural hydrazones were analyzed by high-performance liquid chromatography, phenol and furfuryl alcohol by gas chromatography.

Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds

Science.gov (United States)

Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie

2018-01-01

Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content. PMID:29652811

Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds

Directory of Open Access Journals (Sweden)

Zhenming Zhang

2018-04-01

Full Text Available Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.

Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds.

Science.gov (United States)

Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie; Huang, Xianfei

2018-04-13

Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km², 4.50 km², and 1.87 km², respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.

Influence of Sample Size on Automatic Positional Accuracy Assessment Methods for Urban Areas

Directory of Open Access Journals (Sweden)

Francisco J. Ariza-López

2018-05-01

Full Text Available In recent years, new approaches aimed to increase the automation level of positional accuracy assessment processes for spatial data have been developed. However, in such cases, an aspect as significant as sample size has not yet been addressed. In this paper, we study the influence of sample size when estimating the planimetric positional accuracy of urban databases by means of an automatic assessment using polygon-based methodology. Our study is based on a simulation process, which extracts pairs of homologous polygons from the assessed and reference data sources and applies two buffer-based methods. The parameter used for determining the different sizes (which range from 5 km up to 100 km has been the length of the polygons’ perimeter, and for each sample size 1000 simulations were run. After completing the simulation process, the comparisons between the estimated distribution functions for each sample and population distribution function were carried out by means of the Kolmogorov–Smirnov test. Results show a significant reduction in the variability of estimations when sample size increased from 5 km to 100 km.

Current status of the waste identification program at AECL's Chalk River Laboratories

International Nuclear Information System (INIS)

Csullog, G.W.; Edwards, N.W.; TerHuurne, M.A.

1998-01-01

The management of routine operating waste by Waste Management and Decommissioning (WM and D) at Atomic Energy of Canada Limited's (AECL) Chalk River Laboratories (CRL) is supported by the Waste Identification (WI) Program. The principal purpose of the WI Program is to minimize the cost and the effort associated with waste characterization and waste tracking, which are needed to optimize waste handling, storage and disposal. The major steps in the WI Program are: (1) identify and characterize the processes that generate the routine radioactive wastes accepted by WM and D - radioisotope production, radioisotope use, reactor operation, fuel fabrication, et cetera (2) identify and characterize the routine blocks of waste generated by each process or activity - the initial characterization is based on inference (process knowledge) (3) prepare customized, template data sheets for each routine waste block - templates contain information such as package type, waste material, waste type, solidifying agent, the average non-radiological contaminant inventory, the average radiological contaminant inventory, and the waste class (4) ensure generators 'use the right piece of paper with the right waste' when they transfer waste to WM and D - that is they use the correct template data sheets to transfer routine wastes, by: identifying and marking waste collection points in the generator's facility; ensuring that generators implement effective waste collection/segregation procedures; implementing standard procedures to transfer waste to WM and D; and, auditing waste collection and segregation within a generator's facility (5) determine any additional waste block characterization requirements (is anything needed beyond the original characterization by process knowledge?) This paper describes the WI Program, it provides an example of its implementation, and it summarizes the current status of its implementation for both CRL and non-CRL waste generators. (author)

Influence of sampling depth and post-sampling analysis time on the ...

African Journals Online (AJOL)

Bacteriological analysis was carried out for samples taken at water depth and at 1, 6, 12 and 24 hours post-sampling. It was observed that the total and faecal coliform bacteria were significantly higher in the 3 m water depth samples than in the surface water samples (ANOVA, F = 59.41, 26.751, 9.82 (T.C); 46.41, 26.81, ...

Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds.

Directory of Open Access Journals (Sweden)

Alyssa Bell

Full Text Available The Smoky Hill Member of the Niobrara Chalk in Kansas (USA has yielded the remains of numerous members of the Hesperornithiformes, toothed diving birds from the late Early to Late Cretaceous. This study presents a new taxon of hesperornithiform from the Smoky Hill Member, Fumicollis hoffmani, the holotype of which is among the more complete hesperornithiform skeletons. Fumicollis has a unique combination of primitive (e.g. proximal and distal ends of femur not expanded, elongate pre-acetabular ilium, small and pyramidal patella and derived (e.g. dorsal ridge on metatarsal IV, plantarly-projected curve in the distal shaft of phalanx III:1 hesperornithiform characters, suggesting it was more specialized than small hesperornithiforms like Baptornis advenus but not as highly derived as the larger Hesperornis regalis. The identification of Fumicollis highlights once again the significant diversity of hesperornithiforms that existed in the Late Cretaceous Western Interior Seaway. This diversity points to the existence of a complex ecosystem, perhaps with a high degree of niche partitioning, as indicated by the varying degrees of diving specializations among these birds.

Management of legacy spent nuclear fuel wastes at the Chalk River Laboratories: operating experience and progress towards waste remediation

International Nuclear Information System (INIS)

Cox, D.S.; Bainbridge, I.B.; Greenfield, K.R.

2006-01-01

AECL has been managing and storing a diversity of spent nuclear fuel, arising from operations at its Chalk River Laboratories (CRL) site over more than 50 years. A subset of about 22 tonnes of research reactor fuels, primarily metallic uranium, have been identified as a high priority for remediation, based on monitoring and inspection that has determined that these fuels and their storage containers are corroding. This paper describes the Fuel Packaging and Storage (FPS) project, which AECL has launched to retrieve these fuels from current storage, and to emplace them in a new above-ground dry storage system, as a prerequisite step to decommissioning some of the early-design waste storage structures at CRL. The retrieved fuels will be packaged in a new storage container, and subjected to a cold vacuum drying process that will remove moisture, and thereby reduce the extent of future corrosion and degradation. The FPS project will enable improved interim storage to be implemented for legacy fuels at CRL, until a decision is made on the ultimate disposition of legacy fuels in Canada. (author)

PowerPoint or chalk and talk: Perceptions of medical students versus dental students in a medical college in India

Science.gov (United States)

Seth, Vikas; Upadhyaya, Prerna; Ahmad, Mushtaq; Moghe, Vijay

2010-01-01

Purpose To assess students’ perceptions of the impact of PowerPoint (PPT) presentations in lectures in comparison to the traditional chalk and talk method and lectures using transparencies and overhead projector (TOHP). The study analyzes the preferences for teaching aids of medical students versus dental students. Methods Second year medical and dental undergraduates were asked to fill in a nine-item questionnaire about their perceptions of the three lecture delivery methods. Following analysis of the questionnaire the students were interviewed further. The results were analyzed separately for medical and dental students to see if there was any difference in their perceptions. Results The majority of the medical students (65.33%) preferred PPT presentations, while 15.16% of students preferred the lectures using chalkboard, and 19.51% preferred TOHP for teaching (P lectures (P lecture delivery method. It appears that in the hands of a trained teacher any teaching aid would be appropriate and effective. This highlights the need for formal training in teaching technologies to develop good presentation skills and thus motivate the students. PMID:23745057

Physical behaviour of Cretaceous calcareous nannofossil ooze

DEFF Research Database (Denmark)

Buls, Toms; Anderskouv, Kresten; Friend, Patrick L.

2017-01-01

Geomorphic features such as drifts, sediment waves and channels have been documented in the Upper Cretaceous of north-west Europe. These features are interpreted to result from bottom currents and have been used to refine chalk depositional models and quantify palaeocirculation patterns. Chalk...... was first deposited as calcareous nannofossil ooze and geomorphic features are the result of sediment reworking after deposition. There is limited knowledge on the processes that govern nannofossil ooze mobility, thus forcing uncertainty onto numerical models based on sedimentological observations...... of deposition thresholds (τcd) from ca 0·04 to 0·13 Pa reflects the influence of variable suspended sediment concentration and τ0 on settling particle size due to the identified potential for chalk ooze aggregation and flocculation. Additionally, deposition thresholds seem to be affected by the size of eroded...

Likely-clean concrete disposition at Chalk River Laboratories

International Nuclear Information System (INIS)

Betts, J.A.

2011-01-01

The vast majority of wastes produced at nuclear licensed sites are no different from wastes produced from other traditional industrial activities. Radiation and contamination control practices ensure that the small amounts of waste materials that contain a radiation and or contamination hazard are segregated and managed appropriately according to the level of hazard. Part of the segregation process involves additional clearance checks of wastes generated in areas where the potential to become radioactively contaminated exists, but is very small and contamination control practices are such that the wastes are believed to be 'likely-clean'. This important clearance step helps to ensure that radioactive contamination is not inadvertently released during disposition of inactive waste materials. Clearance methods for bagged likely-clean wastes (i.e. small volumes of low density wastes) or discreet non-bagged items are well advanced. Clearance of bagged likely-clean wastes involves measuring small volumes of bagged material within purpose built highly sensitive bag monitors. For non-bagged items the outer surfaces are scanned to check for surface contamination using traditional hand-held contamination instrumentation. For certain very bulky and porous materials (such as waste concrete), these traditional clearance methods are impractical or not fully effective. As a somewhat porous (and dense) material, surface scanning cannot always be demonstrated to be conclusive. In order to effectively disposition likely-clean concrete, both the method of clearance (i.e. conversion from likely-clean to clean) and method of disposition have to be considered. Likely-clean concrete wastes have been produced at Chalk River Laboratories (CRL) from demolitions of buildings and structures, as well as small amounts from site maintenance activities. A final disposition method for this material that includes the secondary clearance check that changes the classification of this

Likely-clean concrete disposition at Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Betts, J.A. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2011-07-01

The vast majority of wastes produced at nuclear licensed sites are no different from wastes produced from other traditional industrial activities. Radiation and contamination control practices ensure that the small amounts of waste materials that contain a radiation and or contamination hazard are segregated and managed appropriately according to the level of hazard. Part of the segregation process involves additional clearance checks of wastes generated in areas where the potential to become radioactively contaminated exists, but is very small and contamination control practices are such that the wastes are believed to be 'likely-clean'. This important clearance step helps to ensure that radioactive contamination is not inadvertently released during disposition of inactive waste materials. Clearance methods for bagged likely-clean wastes (i.e. small volumes of low density wastes) or discreet non-bagged items are well advanced. Clearance of bagged likely-clean wastes involves measuring small volumes of bagged material within purpose built highly sensitive bag monitors. For non-bagged items the outer surfaces are scanned to check for surface contamination using traditional hand-held contamination instrumentation. For certain very bulky and porous materials (such as waste concrete), these traditional clearance methods are impractical or not fully effective. As a somewhat porous (and dense) material, surface scanning cannot always be demonstrated to be conclusive. In order to effectively disposition likely-clean concrete, both the method of clearance (i.e. conversion from likely-clean to clean) and method of disposition have to be considered. Likely-clean concrete wastes have been produced at Chalk River Laboratories (CRL) from demolitions of buildings and structures, as well as small amounts from site maintenance activities. A final disposition method for this material that includes the secondary clearance check that changes the classification of this

Influence of sampling interval and number of projections on the quality of SR-XFMT reconstruction

International Nuclear Information System (INIS)

Deng Biao; Yu Xiaohan; Xu Hongjie

2007-01-01

Synchrotron Radiation based X-ray Fluorescent Microtomography (SR-XFMT) is a nondestructive technique for detecting elemental composition and distribution inside a specimen with high spatial resolution and sensitivity. In this paper, computer simulation of SR-XFMT experiment is performed. The influence of the sampling interval and the number of projections on the quality of SR-XFMT image reconstruction is analyzed. It is found that the sampling interval has greater effect on the quality of reconstruction than the number of projections. (authors)

Model description of CHERPAC (Chalk River Environmental Research Pathways Analysis Code); results of testing with post-Chernobyl data from Finland

Energy Technology Data Exchange (ETDEWEB)

Peterson, S-R

1994-07-01

CHERPAC (Chalk River Environmental Research Pathways Analysis Code), a time-dependent code for assessing doses from accidental and routine releases of radionuclides, has been under development since 1987. A complete model description is provide here with equations, parameter values, assumptions and information on parameter distributions for uncertainty analysis. Concurrently, CHERPAC has been used to participate in the two internal model validation exercises BIOMOVS (BIOspheric MOdel Validation Study) and VAMP (VAlidation of Assessment Model Predictions, a co-ordinated research program of the International Atomic Energy Agency). CHERPAC has been tested for predictions of concentrations of {sup 137}Cs in foodstuffs, body burden and dose over time using data collected after the Chernobyl accident of 1986 April. CHERPAC`s results for the recent VAMP scenario for southern Finland are particularly accurate and should represent what the code can do under Canadian conditions. CHERPAC`s predictions are compared with the observations from Finland for four and one-half years after the accident as well as with the results of the other participating models from nine countries. (author). 18 refs., 23 figs., 2 appendices.

Model description of CHERPAC (Chalk River Environmental Research Pathways Analysis Code); results of testing with post-Chernobyl data from Finland

International Nuclear Information System (INIS)

Peterson, S-R.

1994-07-01

CHERPAC (Chalk River Environmental Research Pathways Analysis Code), a time-dependent code for assessing doses from accidental and routine releases of radionuclides, has been under development since 1987. A complete model description is provide here with equations, parameter values, assumptions and information on parameter distributions for uncertainty analysis. Concurrently, CHERPAC has been used to participate in the two internal model validation exercises BIOMOVS (BIOspheric MOdel Validation Study) and VAMP (VAlidation of Assessment Model Predictions, a co-ordinated research program of the International Atomic Energy Agency). CHERPAC has been tested for predictions of concentrations of 137 Cs in foodstuffs, body burden and dose over time using data collected after the Chernobyl accident of 1986 April. CHERPAC's results for the recent VAMP scenario for southern Finland are particularly accurate and should represent what the code can do under Canadian conditions. CHERPAC's predictions are compared with the observations from Finland for four and one-half years after the accident as well as with the results of the other participating models from nine countries. (author). 18 refs., 23 figs., 2 appendices

Influence of feed provisioning prior to digesta sampling on precaecal amino acid digestibility in broiler chickens.

Science.gov (United States)

Siegert, Wolfgang; Ganzer, Christian; Kluth, Holger; Rodehutscord, Markus

2018-06-01

A regression approach was applied to determine the influence of feed provisioning prior to digesta sampling on precaecal (pc) amino acid (AA) digestibility in broiler chickens. Soybean meal was used as an example test ingredient. Five feed-provisioning protocols were investigated, four with restricted provision and one with ad libitum provision. When provision was restricted, feed was provided for 30 min after a withdrawal period of 12 h. Digesta were sampled 1, 2, 4 and 6 h after feeding commenced. A diet containing 300 g maize starch/kg was prepared. Half or all the maize starch was replaced with soybean meal in two other diets. Average pc digestibility of all determined AA in the soybean meal was 86% for the 4 and 6-h protocols and 66% and 60% for the 2 and 1-h protocols, respectively. Average pc AA digestibility of soybean meal was 76% for ad libitum feed provision. Feed provisioning also influenced the determined variance. Variance in digestibility ranked in magnitude 1 h > ad libitum > 2 h > 6 h > 4 h for all AA. Owing to the considerable influence of feed-provisioning protocols found in this study, comparisons of pc AA digestibility between studies applying different protocols prior to digesta sampling must be treated with caution. Digestibility experiments aimed at providing estimates for practical feed formulation should use feed-provisioning procedures similar to those used in practice.

Quantifying the influence of sediment source area sampling on detrital thermochronometer data

Science.gov (United States)

Whipp, D. M., Jr.; Ehlers, T. A.; Coutand, I.; Bookhagen, B.

2014-12-01

Detrital thermochronology offers a unique advantage over traditional bedrock thermochronology because of its sensitivity to sediment production and transportation to sample sites. In mountainous regions, modern fluvial sediment is often collected and dated to determine the past (105 to >107 year) exhumation history of the upstream drainage area. Though potentially powerful, the interpretation of detrital thermochronometer data derived from modern fluvial sediment is challenging because of spatial and temporal variations in sediment production and transport, and target mineral concentrations. Thermochronometer age prediction models provide a quantitative basis for data interpretation, but it can be difficult to separate variations in catchment bedrock ages from the effects of variable basin denudation and sediment transport. We present two examples of quantitative data interpretation using detrital thermochronometer data from the Himalaya, focusing on the influence of spatial and temporal variations in basin denudation on predicted age distributions. We combine age predictions from the 3D thermokinematic numerical model Pecube with simple models for sediment sampling in the upstream drainage basin area to assess the influence of variations in sediment production by different geomorphic processes or scaled by topographic metrics. We first consider a small catchment from the central Himalaya where bedrock landsliding appears to have affected the observed muscovite 40Ar/39Ar age distributions. Using a simple model of random landsliding with a power-law landslide frequency-area relationship we find that the sediment residence time in the catchment has a major influence on predicted age distributions. In the second case, we compare observed detrital apatite fission-track age distributions from 16 catchments in the Bhutan Himalaya to ages predicted using Pecube and scaled by various topographic metrics. Preliminary results suggest that predicted age distributions scaled

Integrated waste plan for Chalk River Laboratories

International Nuclear Information System (INIS)

McClelland, P.; Bainbridge, I.

2011-01-01

The core missions for Chalk River Laboratories (CRL) will involve a complex suite of activities for decades to come, many of these activities resulting in production of some amount of wastes. In order to support the business of the Nuclear Laboratories there is a requirement to responsibly manage the wastes arising from these activities. Capability to develop waste stream pathway scenarios and be able to make informed strategic decisions regarding the various options for waste processing, storage and long-term management (i.e. e nabling facilities ) is necessary to discharge this responsibility in the most cost effective and sustainable manner. A holistic waste management plan integrated with the decommissioning, environmental remediation and operations programs is the desired result such that: - Waste inputs and timings are identified; - Timing of key decisions regarding enabling facilities is clearly identified; and - A defensible decision-making framework for enabling facilities is established, thereby ensuring value for Canadians. The quantities of wastes that require managing as part of the Nuclear Legacy Liabilities Program and AECL operations activities is in the range of 200,000 to 300,000 m 3 , with a yearly increase of several thousand m 3 . This volume can be classified into over thirty distinct waste streams having differing life cycle waste management pathways from generation to disposition. The time phasing of the waste management activities required for these wastes spans several decades and involves a complex array of processes and facilities. Several factors typical of wastes from the development of nuclear technology further complicate the situation. For example, there is considerable variation in the level of detail and format of waste records generated over several decades. Also, wastes were put into storage over several decades without knowledge or consideration of what the final disposition path will be. Prior to proceeding with any major new

Assessing the drivers of dissolved organic matter export from two contrasting lowland catchments, U.K.

Science.gov (United States)

Yates, Christopher A; Johnes, Penny J; Spencer, Robert G M

2016-11-01

Two lowland catchments in the U.K. were sampled throughout 2010-11 to investigate the dominant controls on dissolved organic matter quantity and composition. The catchments had marked differences in terms of nutrient status, land cover and contrasting lithologies resulting in differences in the dominant flow pathways (groundwater vs. surface water dominated). The Upper Wylye is a chalk stream with a baseflow index of 0.98, draining a catchment dominated by intensive agricultural production. Millersford Brook is a lowland peat catchment with a baseflow index of 0.43, draining a semi-natural catchment with heather moorland and coniferous forest. Samples were collected weekly between October 2010 and September 2011 from eleven sampling locations. Samples were analysed to determine dissolved organic carbon, nitrogen and phosphorus fractions with DOM composition evaluated via the DOC:DON ratio, DOC:DOP ratio, specific UV absorption at 254nm, absorbance ratio (a250:a365) and the spectral slope parameter between 350 and 400nm (S350-400). Significant differences were observed in all determinands between the catchments, over time, and spatially along nutrient enrichment and geoclimatic gradients. Seasonal variation in preferential flow pathways mobilising groundwater-derived DOM were identified as likely controls on the delivery of DOM in the permeable chalk dominated catchment. Steeper S350-400 values and elevated a250:a365 ratios in this catchment suggest material of a lower bulk aromatic C content and molecular weight delivered during the winter months when compared to the summer. DOC:DON ratios were markedly lower in the chalk catchment than the peatland catchment, reflecting the paucity of organic matter within the mineral soils of the chalk landscape, and higher fertiliser application rates. This manuscript highlights that DOM composition varies according to catchment landscape character and hydrological function. Copyright © 2016 The Authors. Published by Elsevier B

Hydrogeochemical processes affecting the migration of radionuclides in a fluvial sand aquifer at the Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Jackson, R.E.; Inch, K.J.

1980-01-01

In the mid-1950's two experimental disposals of liquid radioactive waste containing about 700 curries of strontium-90 and cesium-137 were made into pits in sandy ground at one of the disposal areas at Chalk River Nuclear Laboratories. Since then, the wastes have migrated into two nearby aquifers and have chromatographically separated into strontium-90 and cesium-137 plumes moving at velocities less than that of the transporting groundwater. Analysis of radioactively contaminated aquifer sediments showed that most of the strontium-90 is exchangeably adsorbed, primarily to feldspars and layer silicates (mainly biotite); the rest is either specifically adsorbed to iron (III) and perhaps manganese (IV) oxhydroxides or fixed to unknown sinks. Less than one half of adsorbed cesium-137 is exchangeable with 0.5 m calcium chloride; the high levels of cesium-137 adsorption and fixation are probably due to its reaction with micaceous minerals. Complexation of strontium-90 and cesium-137 does not appear to be an important factor affecting their transport or adsorption. In studies of groundwater quality or pollution, dissolved oxygen and sulfide should be measured in addition to the redox potential since it allows independent assessment of the redox levels. The latter were found to affect the mobility of multivalent transition metals and nonmetals. (DN)

Influence of heart rate in nonlinear HRV indices as a sampling rate effect evaluated on supine and standing

Directory of Open Access Journals (Sweden)

Juan Bolea

2016-11-01

Full Text Available The purpose of this study is to characterize and attenuate the influence of mean heart rate (HR on nonlinear heart rate variability (HRV indices (correlation dimension, sample and approximate entropy as a consequence of being the HR the intrinsic sampling rate of HRV signal. This influence can notably alter nonlinear HRV indices and lead to biased information regarding autonomic nervous system (ANS modulation.First, a simulation study was carried out to characterize the dependence of nonlinear HRV indices on HR assuming similar ANS modulation. Second, two HR-correction approaches were proposed: one based on regression formulas and another one based on interpolating RR time series. Finally, standard and HR-corrected HRV indices were studied in a body position change database.The simulation study showed the HR-dependence of non-linear indices as a sampling rate effect, as well as the ability of the proposed HR-corrections to attenuate mean HR influence. Analysis in a body position changes database shows that correlation dimension was reduced around 21% in median values in standing with respect to supine position (p < 0.05, concomitant with a 28% increase in mean HR (p < 0.05. After HR-correction, correlation dimension decreased around 18% in standing with respect to supine position, being the decrease still significant. Sample and approximate entropy showed similar trends.HR-corrected nonlinear HRV indices could represent an improvement in their applicability as markers of ANS modulation when mean HR changes.

Influence of sample composition on aerosol organic and black carbon determinations

Energy Technology Data Exchange (ETDEWEB)

Novakov, T.; Corrigan, C.E.

1995-07-01

In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550{degrees}C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations.

Influence of sample composition on aerosol organic and black carbon determinations

International Nuclear Information System (INIS)

Novakov, T.; Corrigan, C.E.

1995-07-01

In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550 degrees C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations

Trace elements in a North Sea drill core

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Gwozdz, R.; Svendsen, N.

1986-01-01

, V, Sr, Dy, Mg, Ti, Ba and Eu. The major elements Ca and Al could be related to petrophysical parameters, particularly Al which shows a correlation with the silicification/argillaceous content. Na (and Cl) has a low content in the hydrocarbon-bearing section of the drill core suggesting that the pore......Chalk samples, systematically taken along a drill core from one of the hydrocarbon producing fields of the North Sea (Tyra field), were analysed by a neutron activation technique involving measurement of radioisotopes with relatively short half-lives. Elements determined include Na, Al, Cl, Ca, Mn...... space is filled mainly by hydrocarbons. A significant decrease of Mn with depth probably suggests diagenesis of chalk prior to, or with, hydrocarbon emplacement. Investigations of drilling fluids and cuttings reveal a strong contamination of the latter, mainly by Ba. Chalk data from comparable onshore...

3D synchrotron x-ray microtomography of paint samples

Science.gov (United States)

Ferreira, Ester S. B.; Boon, Jaap J.; van der Horst, Jerre; Scherrer, Nadim C.; Marone, Federica; Stampanoni, Marco

2009-07-01

Synchrotron based X-ray microtomography is a novel way to examine paint samples. The three dimensional distribution of pigment particles, binding media and their deterioration products as well as other features such as voids, are made visible in their original context through a computing environment without the need of physical sectioning. This avoids manipulation related artefacts. Experiments on paint chips (approximately 500 micron wide) were done on the TOMCAT beam line (TOmographic Microscopy and Coherent rAdiology experimenTs) at the Paul Scherrer Institute in Villigen, CH, using an x-ray energy of up to 40 keV. The x-ray absorption images are obtained at a resolution of 350 nm. The 3D dataset was analysed using the commercial 3D imaging software Avizo 5.1. Through this process, virtual sections of the paint sample can be obtained in any orientation. One of the topics currently under research are the ground layers of paintings by Cuno Amiet (1868- 1961), one of the most important Swiss painters of classical modernism, whose early work is currently the focus of research at the Swiss Institute for Art Research (SIK-ISEA). This technique gives access to information such as sample surface morphology, porosity, particle size distribution and even particle identification. In the case of calcium carbonate grounds for example, features like microfossils present in natural chalks, can be reconstructed and their species identified, thus potentially providing information towards the mineral origin. One further elegant feature of this technique is that a target section can be selected within the 3D data set, before exposing it to obtain chemical data. Virtual sections can then be compared with cross sections of the same samples made in the traditional way.

Clicks and Bricks: How School Buildings Influence Future Practice and Technology Adoption

Science.gov (United States)

McIntosh, Ewan

2011-01-01

Digital land knows no boundaries of space, time or geography. The effect on learning in the past three years, in particular, has been profound, though not necessarily on learning in schools. More have arguably expanded their horizons through 20 minutes of TED Talks than 20 minutes of most chalk and talks or classroom activities.

Estimating fish swimming metrics and metabolic rates with accelerometers: the influence of sampling frequency.

Science.gov (United States)

Brownscombe, J W; Lennox, R J; Danylchuk, A J; Cooke, S J

2018-06-21

Accelerometry is growing in popularity for remotely measuring fish swimming metrics, but appropriate sampling frequencies for accurately measuring these metrics are not well studied. This research examined the influence of sampling frequency (1-25 Hz) with tri-axial accelerometer biologgers on estimates of overall dynamic body acceleration (ODBA), tail-beat frequency, swimming speed and metabolic rate of bonefish Albula vulpes in a swim-tunnel respirometer and free-swimming in a wetland mesocosm. In the swim tunnel, sampling frequencies of ≥ 5 Hz were sufficient to establish strong relationships between ODBA, swimming speed and metabolic rate. However, in free-swimming bonefish, estimates of metabolic rate were more variable below 10 Hz. Sampling frequencies should be at least twice the maximum tail-beat frequency to estimate this metric effectively, which is generally higher than those required to estimate ODBA, swimming speed and metabolic rate. While optimal sampling frequency probably varies among species due to tail-beat frequency and swimming style, this study provides a reference point with a medium body-sized sub-carangiform teleost fish, enabling researchers to measure these metrics effectively and maximize study duration. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

A novel sample preparation method to avoid influence of embedding medium during nano-indentation

Science.gov (United States)

Meng, Yujie; Wang, Siqun; Cai, Zhiyong; Young, Timothy M.; Du, Guanben; Li, Yanjun

2013-02-01

The effect of the embedding medium on the nano-indentation measurements of lignocellulosic materials was investigated experimentally using nano-indentation. Both the reduced elastic modulus and the hardness of non-embedded cell walls were found to be lower than those of the embedded samples, proving that the embedding medium used for specimen preparation on cellulosic material during nano-indentation can modify cell-wall properties. This leads to structural and chemical changes in the cell-wall constituents, changes that may significantly alter the material properties. Further investigation was carried out to detect the influence of different vacuum times on the cell-wall mechanical properties during the embedding procedure. Interpretation of the statistical analysis revealed no linear relationships between vacuum time and the mechanical properties of cell walls. The quantitative measurements confirm that low-viscosity resin has a rapid penetration rate early in the curing process. Finally, a novel sample preparation method aimed at preventing resin diffusion into lignocellulosic cell walls was developed using a plastic film to wrap the sample before embedding. This method proved to be accessible and straightforward for many kinds of lignocellulosic material, but is especially suitable for small, soft samples.

Influence of the sample anticoagulant on the measurements of impedance aggregometry in cardiac surgery

Directory of Open Access Journals (Sweden)

Cristina Solomon

2008-10-01

Full Text Available Cristina Solomon1, Michael Winterhalter1, Isabel Gilde1, Ludwig Hoy2, Andreas Calatzis3, Niels Rahe-Meyer11Department of Anesthesiology, Hannover Medical School, Hannover, Germany; 2Institute for Biometry, Hannover Medical School, Hannover, Germany; 3Department Hemostasis Transfusion Medicine, University Hospital Munich, Munich, GermanyBackground: The standard method of assessment of platelet function is represented by light transmission aggregometry (LTA, performed in citrated platelet-rich plasma (PRP. With LTA, decrease and subsequent post-cardiopulmonary bypass (CPB recovery of platelet function have been reported during cardiac surgery. Multiple electrode aggregometry (MEA may be used as point-of-care method to monitor perioperative changes in platelet function. Since MEA assesses macroaggregation which is influenced by the plasmatic levels of unbound calcium, citrate may be inadequate as anticoagulant for MEA. We used citrate and heparin for MEA samples, to see with which anticoagulant the intraoperative decrease and postoperative recovery in platelet function previously described with other aggregometric methods in cardiac surgery may be observed with MEA.Methods: Blood was obtained from 60 patients undergoing routine cardiac surgery and the samples were collected in standard tubes containing unfractionated heparin (50 U/mL or trisodium citrate (3.2%. The samples were obtained before CPB, at 30 minutes on CPB, end of CPB and on the first postoperative day. MEA was performed using the Multiplate® analyzer. Collagen (COLtest, 100 μg/mL and TRAP-6 (thrombin receptor activating peptide, TRAPtest, 1mM/mL were used as aggregation agonists.Results: Platelet aggregometric response decreased significantly during CPB. Platelet aggregation assessed using TRAP-6 as agonist on heparinized blood significantly correlated with the duration of CPB (r = −0.41, p = 0.001, 2-tailed Pearson test. The aggregometric analysis performed on the first

Determination of the detection limit and decision threshold for ionizing radiation measurements. Part 2: Fundamentals and application to counting measurements with the influence of sample treatment

International Nuclear Information System (INIS)

2000-01-01

This part of ISO 11929 addresses the field of ionizing radiation measurements in which events (in particular pulses) on samples are counted after treating them (e.g. aliquotation, solution, enrichment, separation). It considers, besides the random character of radioactive decay and of pulse counting, all other influences arising from sample treatment, (e.g. weighing, enrichment, calibration or the instability of the test setup). ISO 11929 consists of the following parts, under the general title Determination of the detection limit and decision threshold for ionizing radiation measurements: Part 1: Fundamentals and application to counting measurements without the influence of sample treatment; Part 2: Fundamentals and application to counting measurements with the influence of sample treatment; Part 3: Fundamentals and application to counting measurements by high resolution gamma spectrometry, without the influence of sample treatment; Part 4: Fundamentals and application to measurements by use of linear scale analogue ratemeters, without the influence of sample treatment. This part of ISO 11929 was prepared in parallel with other International Standards prepared by WG 2 (now WG 17): ISO 11932:1996, Activity measurements of solid materials considered for recycling, re-use or disposal as non radioactive waste, and ISO 11929-1, ISO 11929-3 and ISO 11929-4 and is, consequently, complementary to these documents

Influence of audiovisuals and food samples on consumer acceptance of food irradiation

International Nuclear Information System (INIS)

Pohlman, A.J.; Wood, O.B.; Mason, A.C.

1994-01-01

The effects of audiovisual presentation on consumers' knowledge and attitudes toward food irradiation were demonstrated. Food irradiation is a method of food preservation that can destroy the microorganisms responsible for many foodborne illnesses and food spoilage. However, the food industry has been slow to adopt this method because it is unsure of consumer acceptance. One hundred and seventy-nine consumers were given a slide-tape presentation on food irradiation. Test subjects were also presented with a sample of irradiated strawberries. It was found that participants knew more about and were more positive toward food irradiation following the educational program. These findings demonstrate the value of educational materials in influencing the food preferences of consumers

HTO and OBT activity concentrations in soil at the historical atmospheric HT release site (Chalk River Laboratories)

International Nuclear Information System (INIS)

Kim, S.B.; Bredlaw, M.; Korolevych, V.Y.

2012-01-01

Tritium is routinely released by the Chalk River Laboratories (CRL) nuclear facilities. Three International HT release experiments have been conducted at the CRL site in the past. The site has not been disturbed since the last historical atmospheric testing in 1994 and presents an opportunity to assess the retention of tritium in soil. This study is devoted to the measurement of HTO and OBT activity concentration profiles in the subsurface 25 cm of soil. In terms of soil HTO, there is no evidence from the past HT release experiments that HTO was retained. The HTO activity concentration in the soil pore water appears similar to concentrations found in background areas in Ontario. In contrast, OBT activity concentrations in soil at the same site were significantly higher than HTO activity concentrations in soil. Elevated OBT appears to reside in the top layer of the soil (0–5 cm). In addition, OBT activity concentrations in the top soil layer did not fluctuate much with season, again, quite in contrast with soil HTO. This result suggests that OBT activity concentrations retained the signature of the historical tritium releases. Highlights: ► At the historical HT release site, HTO and OBT activity concentrations in soil depths were investigated. ► Most organically bound tritium exists in the top layer of the soil. ► The results indicated that OBT activity concentrations can be reflective of historical tritium releases into the environment.

Influence of Freezing and Storage Procedure on Human Urine Samples in NMR-Based Metabolomics

Directory of Open Access Journals (Sweden)

Burkhard Luy

2013-04-01

Full Text Available It is consensus in the metabolomics community that standardized protocols should be followed for sample handling, storage and analysis, as it is of utmost importance to maintain constant measurement conditions to identify subtle biological differences. The aim of this work, therefore, was to systematically investigate the influence of freezing procedures and storage temperatures and their effect on NMR spectra as a potentially disturbing aspect for NMR-based metabolomics studies. Urine samples were collected from two healthy volunteers, centrifuged and divided into aliquots. Urine aliquots were frozen either at −20 °C, on dry ice, at −80 °C or in liquid nitrogen and then stored at −20 °C, −80 °C or in liquid nitrogen vapor phase for 1–5 weeks before NMR analysis. Results show spectral changes depending on the freezing procedure, with samples frozen on dry ice showing the largest deviations. The effect was found to be based on pH differences, which were caused by variations in CO2 concentrations introduced by the freezing procedure. Thus, we recommend that urine samples should be frozen at −20 °C and transferred to lower storage temperatures within one week and that freezing procedures should be part of the publication protocol.

Influence of Freezing and Storage Procedure on Human Urine Samples in NMR-Based Metabolomics.

Science.gov (United States)

Rist, Manuela J; Muhle-Goll, Claudia; Görling, Benjamin; Bub, Achim; Heissler, Stefan; Watzl, Bernhard; Luy, Burkhard

2013-04-09

It is consensus in the metabolomics community that standardized protocols should be followed for sample handling, storage and analysis, as it is of utmost importance to maintain constant measurement conditions to identify subtle biological differences. The aim of this work, therefore, was to systematically investigate the influence of freezing procedures and storage temperatures and their effect on NMR spectra as a potentially disturbing aspect for NMR-based metabolomics studies. Urine samples were collected from two healthy volunteers, centrifuged and divided into aliquots. Urine aliquots were frozen either at -20 °C, on dry ice, at -80 °C or in liquid nitrogen and then stored at -20 °C, -80 °C or in liquid nitrogen vapor phase for 1-5 weeks before NMR analysis. Results show spectral changes depending on the freezing procedure, with samples frozen on dry ice showing the largest deviations. The effect was found to be based on pH differences, which were caused by variations in CO2 concentrations introduced by the freezing procedure. Thus, we recommend that urine samples should be frozen at -20 °C and transferred to lower storage temperatures within one week and that freezing procedures should be part of the publication protocol.

Influence of the tip mass on the tip-sample interactions in TM-AFM

Energy Technology Data Exchange (ETDEWEB)

Pishkenari, Hossein Nejat, E-mail: nejat@mech.sharif.edu [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of); Meghdari, Ali [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of)

2011-07-15

This paper focuses on the influences of the tip mass ratio (the ratio of the tip mass to the cantilever mass), on the excitation of higher oscillation eigenmodes and also on the tip-sample interaction forces in tapping mode atomic force microscopy (TM-AFM). A precise model for the cantilever dynamics capable of accurate simulations is essential for the investigation of the tip mass effects on the interaction forces. In the present work, the finite element method (FEM) is used for modeling the AFM cantilever to consider the oscillations of higher eigenmodes oscillations. In addition, molecular dynamics (MD) is used to calculate precise data for the tip-sample force as a function of tip vertical position with respect to the sample. The results demonstrate that in the presence of nonlinear tip-sample interaction forces, the tip mass ratio plays a significant role in the excitations of higher eigenmodes and also in the normal force applied on the surface. Furthermore, it has been shown that the difference between responses of the FEM and point-mass models in different system operational conditions is highly affected by the tip mass ratio. -- Highlights: {yields} A strong correlation exists between the tip mass ratio and the 18th harmonic amplitude. {yields} Near the critical tip mass ratio a small change in the tip mass may lead to a significant force change. {yields} Inaccuracy of the lumped model depends significantly on the tip mass ratio.

Seminar for labour on the objectives and work of CRNL May 29, 30, 31, 1972

International Nuclear Information System (INIS)

1972-01-01

The Seminar for Labour on the Objectives and Work of CRNL was held in Chalk River, Ontario, Canada on May 29-31, 1972. The main objective is to review the work and contributions of employees at Chalk River Nuclear Laboratories. Three specific matters communicated at the conference are: a full sense of pride in the achievements the employees have helped to bring about; a realization that CRNL has a long future ahead of it and though much as been accomplished, much more remains to be done; and, that Chalk River is a good place to work and there is a high regard for the safety of every employee. Not all aspects of work done at CRNL could be presented, however the selected samples cover a fairly large spectrum of the functions in the Laboratories. This document provides the opportunity to determine just how large and essential a role the employees and the Laboratory has played and will continue to play in Canadian and world wide affairs.

Influence of population versus convenience sampling on sample characteristics in studies of cognitive aging.

Science.gov (United States)

Brodaty, Henry; Mothakunnel, Annu; de Vel-Palumbo, Melissa; Ames, David; Ellis, Kathryn A; Reppermund, Simone; Kochan, Nicole A; Savage, Greg; Trollor, Julian N; Crawford, John; Sachdev, Perminder S

2014-01-01

We examined whether differences in findings of studies examining mild cognitive impairment (MCI) were associated with recruitment methods by comparing sample characteristics in two contemporaneous Australian studies, using population-based and convenience sampling. The Sydney Memory and Aging Study invited participants randomly from the electoral roll in defined geographic areas in Sydney. The Australian Imaging, Biomarkers and Lifestyle Study of Ageing recruited cognitively normal (CN) individuals via media appeals and MCI participants via referrals from clinicians in Melbourne and Perth. Demographic and cognitive variables were harmonized, and similar diagnostic criteria were applied to both samples retrospectively. CN participants recruited via convenience sampling were younger, better educated, more likely to be married and have a family history of dementia, and performed better cognitively than those recruited via population-based sampling. MCI participants recruited via population-based sampling had better memory performance and were less likely to carry the apolipoprotein E ε4 allele than clinically referred participants but did not differ on other demographic variables. A convenience sample of normal controls is likely to be younger and better functioning and that of an MCI group likely to perform worse than a purportedly random sample. Sampling bias should be considered when interpreting findings. Copyright © 2014 Elsevier Inc. All rights reserved.

How does observation uncertainty influence which stream water samples are most informative for model calibration?

Science.gov (United States)

Wang, Ling; van Meerveld, Ilja; Seibert, Jan

2016-04-01

occurred, the mixing processes were more complex and the information content of streamflow samples decreased. Therefore, for these cases, samples taken at the start or end of overflow were most informative. We, furthermore, investigated how observation errors influenced the multi-criteria calibration process. Preliminary results show that more than two samples are needed to maintain a similar simulation performance when observation errors in precipitation or streamflow are included. These results provide guidance on suitable event-based sampling strategies for different conditions.

Geophysical features of uranium mineralization in Wadi Bahiya area, southern Jordan

International Nuclear Information System (INIS)

Zhao Xigang; Liang Shanming; Deng Xiaowei; Li Shengxiang; Wang Jinping

2010-01-01

Based on comprehensive study of geologic survey, sample analysis and ground gamma spectral survey, it is concluded that the uranium mineralization in Wadi Bahiya area, southern Jordan occurs near surface and is mostly hosted in weathered gray-brown chalk marl of Muwaqqar Chalk Marl Formation of the Upper Cretaceous and Paleocene, and belongs to surficial calcrete-type which is related to modern oxidation. The ground gamma spectral survey shows that surface anomaly area is small and big gradient change of the anomalies. The trenches reveal that uranium content of the anomalies falls down from near-surface to the deep. The analytical results of the samples from the area correspond with the gamma spectral measurements, demonstrating that uranium mineralization is mainly located within the depth between 0.5 and 1.5 m. (authors)

Influence of the neutron flux shape on the value of absorbed neutron dose; Uticaj oblika neutronskog spektra na vrednost apsorbovane doze neutrona

Energy Technology Data Exchange (ETDEWEB)

Miric, I; Miric, P [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1974-07-01

This paper deals with the study od specific doses dependence on the type and approximation procedures of neutron spectra. Values of specific dose rates (dose per neutron cm{sub 2}) were analysed for neutron spectra from RB reactor in Vinca, Crac facility in Valduc (France) and HPRR reactor in Oak Ridge (USA). Data used in this analysis were obtained by methods used in Harwell (AERE), Oak Ridge (ORNL), Chalk River (AECL), CEN de Cadarache (CEA) and in the Boris Kidric Institute (IBK). Specific absorbed neutron doses were determined for each of the estimated spectra and presented in the form of kerma/(n.cm{sup -2}) and rad/((n.cm{sup -2}) units. The obtained results have shown the influence of the flux approximation procedure on the values of conversion factors for obtaining neutron doses from neutron flux. U okviru ovog rada radjeno je na ispitivanju zavisnosti specificnih doza od vrste i nacina aproksimacije neutronskog spektra. U radu su analizirane vrednosti specificnih doza (doza po n.cm{sup -2}) za neutronske spektre koji se dobijaju oko sledecih nuklearnih postrojenja: reaktora RB u Vinci, postrojenja CRAC u Valduc-u (Francuska), reaktora HPRR u Oak Ridge-u (SAD). Za analizu su korisceni podaci dobijeni metodama koje se koriste u nuklearnim centrima Harwell (AERE), Oak Ridge-u (ORNL), Chalk River-u (AECL), CEN de Cadarache (CEA) i Institutu Boris Kidric (IBK). Za svaki procenjeni spektar odredjene su specificne apsorbovane doze neutrona izrazene u kerma/(n.cm{sup -2}) i rad/(n.cm{sup -2}) jedinicama. Dobijeni rezultati su pokazali koliko nacin aproksimacije spektra utice na vrednost konverzionih faktora koji sluze za prelazak sa fluksa na dozu neutrona (author)

Pitfalls in velocity analysis for strongly contrasting, layered media - Example from the Chalk Group, North Sea

Science.gov (United States)

Montazeri, Mahboubeh; Uldall, Anette; Moreau, Julien; Nielsen, Lars

2018-02-01

Knowledge about the velocity structure of the subsurface is critical in key seismic processing sequences, for instance, migration, depth conversion, and construction of initial P- and S-wave velocity models for full-waveform inversion. Therefore, the quality of subsurface imaging is highly dependent upon the quality of the seismic velocity analysis. Based on a case study from the Danish part of the North Sea, we show how interference caused by multiples, converted waves, and thin-layer effects may lead to incorrect velocity estimation, if such effects are not accounted for. Seismic wave propagation inside finely layered reservoir rocks dominated by chalk is described by two-dimensional finite-difference wave field simulation. The rock physical properties used for the modeling are based on an exploration well from the Halfdan field in the Danish sector of the North Sea. The modeling results are compared to seismic data from the study area. The modeling shows that interference of primaries with multiples, converted waves and thin-bed effects can give rise to strong anomalies in standard velocity analysis plots. Consequently, root-mean-square (RMS) velocity profiles may be erroneously picked. In our study area, such mis-picking can introduce errors in, for example, the thickness estimation of the layers near the base of the studied sedimentary strata by 11% to 26%. Tests show that front muting and bandpass filtering cannot significantly improve the quality of velocity analysis in our study. However, we notice that spiking deconvolution applied before velocity analysis may to some extent reduce the impact of interference and, therefore, reduce the risk of erroneous picking of the velocity function.

Use of X-ray computed tomography in core analysis of tight North Sea Chalk. Final report

Energy Technology Data Exchange (ETDEWEB)

Mogensen, K.; Stenby, E.H.

1997-12-01

This EFP-95 final report summarizes work performed at the Engineering Research Center (IVC-SEP) on the use of CT scanning in core analysis of tight core material from the North Sea. In this work, CT scanning has been applied to chalk material from Danish North Sea oil reservoirs. Results indicate that CT is fast and reliable for prediction of porosity. Typical errors lie within 2-3%. Calculation of fluid saturations requires considerable care from the experimentalists. Saturating a core ought to be performed by pulling vacuum to avoid trapped air bubbles. These bubbles may be produced after subsequent water and gas flooding, thereby ruining the mass balance calculations. Results performed at Stanford University show that if these simple precautions are taken, fluid saturations calculated from CT scanning are generally very accurate. Moreover, it appears that contrast agents need not be added to either phase. Regarding three-phase measurements the results are somewhat disappointing. Previous work using the dual-energy technique has indicated that the accuracy is less than satisfactory, due to an increased noise level at the low-energy setting. More work needs to be done in the future to develop the necessary expertise. The image analysis of the residual oil saturation after a gas flood can be simplified if water is assumed to be immobile during the injection. In that case, the resulting prediction of residual oil saturation is in excellent agreement with measured values. The general conclusion is that CT scanning holds a great potential as an assisting tool in modern core analysis, despite its limitations and the numerous implementation-related problems encountered during this work. (au) EFP-95. 57 refs.

Serum thromboxane B2 (TXB2 Determination is Influenced by Sample Incubation Temperature in Healthy Beagle Dogs

Directory of Open Access Journals (Sweden)

Aleš Jerin

2009-01-01

Full Text Available The measurement of serum thromboxane B2 (TXB2 production by platelets is a specific test for assessment of platelet cyclooxygenase (COX-1 activity following administration of non-steroidal anti-inflammatory drugs (NSAIDs. The aim of this study was to investigate the influence of sample incubation at 37 °C for one hour on serum TXB2 concentration in comparison with incubation at room temperature. A total of 54 blood samples for serum TXB2 measurements were collected from six healthy beagle dogs into two separate serum tubes. While one group of tubes was incubated in a 37 °C water bath, the second group of tubes was left to coagulate at room temperature, both for one hour. Serum TXB2 concentrations were measured by ELISA. The mean concentration (± SD of serum TXB2 in the group of samples that were incubated at 37 °C was significantly (P 2 concentration in healthy beagle dogs and demonstrate that validated methods for assessment of COX-1 activity by measurement of serum TXB2 should be used in order to make results more reliable and comparable between different studies. The results of this study might be of great help in planning NSAID studies in dogs by providing the information that TXB2 generation by platelets is influenced profoundly by incubation temperature.

Results of detailed ground geophysical surveys for locating and differentiating waste structures in waste management area 'A' at Chalk River Laboratories, Ontario

International Nuclear Information System (INIS)

Tomsons, D.K.; Street, P.J.; Lodha, G.S.

1999-01-01

Waste Management Area 'A' (WMA 'A'), located in the outer area of the Chalk River Laboratories (CRL) was in use as a waste burial site from 1946 to 1955. Waste management structures include debris-filled trenches, concrete bunkers and miscellaneous contaminated solid materials, and ditches and pits used for liquid dispersal. In order to update historical records, it was proposed to conduct detailed ground geophysical surveys to define the locations of waste management structures in WMA 'A', assist in planning of the drilling and sampling program to provide ground truth for the geophysics investigation and to predict the nature and locations of unknown/undefined shallow structures. A detailed ground geophysical survey grid was established with a total of 127 grid lines, oriented NNE and spaced one metre apart. The geophysical surveys were carried out during August and September, 1996. The combination of geophysical tools used included the Geonics EM61 metal detector, the GSM-19 magnetometer/gradiometer and a RAMAC high frequency ground penetrating radar system. The geophysical surveys were successful in identifying waste management structures and in characterizing to some extent, the composition of the waste. The geophysical surveys are able to determine the presence of most of the known waste management structures, especially in the western and central portions of the grid which contain the majority of the metallic waste. The eastern portion of the grid has a completely different geophysical character. While historical records show that trenches were dug, they are far less evident in the geophysical record. There is clear evidence for a trench running between lines 30E and 63E at 70 m. There are indications from the radar survey of other trench-like structures in the eastern portion. EM61 data clearly show that there is far less metallic debris in the eastern portion. The geophysical surveys were also successful in identifying previously unknown locations of waste

Influences of sampling effort on detected patterns and structuring processes of a Neotropical plant-hummingbird network.

Science.gov (United States)

Vizentin-Bugoni, Jeferson; Maruyama, Pietro K; Debastiani, Vanderlei J; Duarte, L da S; Dalsgaard, Bo; Sazima, Marlies

2016-01-01

Virtually all empirical ecological interaction networks to some extent suffer from undersampling. However, how limitations imposed by sampling incompleteness affect our understanding of ecological networks is still poorly explored, which may hinder further advances in the field. Here, we use a plant-hummingbird network with unprecedented sampling effort (2716 h of focal observations) from the Atlantic Rainforest in Brazil, to investigate how sampling effort affects the description of network structure (i.e. widely used network metrics) and the relative importance of distinct processes (i.e. species abundances vs. traits) in determining the frequency of pairwise interactions. By dividing the network into time slices representing a gradient of sampling effort, we show that quantitative metrics, such as interaction evenness, specialization (H2 '), weighted nestedness (wNODF) and modularity (Q; QuanBiMo algorithm) were less biased by sampling incompleteness than binary metrics. Furthermore, the significance of some network metrics changed along the sampling effort gradient. Nevertheless, the higher importance of traits in structuring the network was apparent even with small sampling effort. Our results (i) warn against using very poorly sampled networks as this may bias our understanding of networks, both their patterns and structuring processes, (ii) encourage the use of quantitative metrics little influenced by sampling when performing spatio-temporal comparisons and (iii) indicate that in networks strongly constrained by species traits, such as plant-hummingbird networks, even small sampling is sufficient to detect their relative importance for the frequencies of interactions. Finally, we argue that similar effects of sampling are expected for other highly specialized subnetworks. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Implementing reduced-risk integrated pest management in fresh-market cabbage: influence of sampling parameters, and validation of binomial sequential sampling plans for the cabbage looper (Lepidoptera Noctuidae).

Science.gov (United States)

Burkness, Eric C; Hutchison, W D

2009-10-01

Populations of cabbage looper, Trichoplusiani (Lepidoptera: Noctuidae), were sampled in experimental plots and commercial fields of cabbage (Brasicca spp.) in Minnesota during 1998-1999 as part of a larger effort to implement an integrated pest management program. Using a resampling approach and the Wald's sequential probability ratio test, sampling plans with different sampling parameters were evaluated using independent presence/absence and enumerative data. Evaluations and comparisons of the different sampling plans were made based on the operating characteristic and average sample number functions generated for each plan and through the use of a decision probability matrix. Values for upper and lower decision boundaries, sequential error rates (alpha, beta), and tally threshold were modified to determine parameter influence on the operating characteristic and average sample number functions. The following parameters resulted in the most desirable operating characteristic and average sample number functions; action threshold of 0.1 proportion of plants infested, tally threshold of 1, alpha = beta = 0.1, upper boundary of 0.15, lower boundary of 0.05, and resampling with replacement. We found that sampling parameters can be modified and evaluated using resampling software to achieve desirable operating characteristic and average sample number functions. Moreover, management of T. ni by using binomial sequential sampling should provide a good balance between cost and reliability by minimizing sample size and maintaining a high level of correct decisions (>95%) to treat or not treat.

Influence of salinity stress on the height and productivity features of durum wheat samples in different phases of vegetation

Directory of Open Access Journals (Sweden)

A. Z. Sikhmuradov

2010-01-01

Full Text Available Influence of salinity stress on the morphological features of durum wheat in different phases of vegetation is studied in the work. It is revealed that in earlier phases the samples have weak stability, but further salt-stability increases.

Study of sampling rate influence on neutron-gamma discrimination with stilbene coupled to a silicon photomultiplier.

Science.gov (United States)

Zhang, Jinglong; Moore, Michael E; Wang, Zhonghai; Rong, Zhou; Yang, Chaowen; Hayward, Jason P

2017-10-01

Choosing a digitizer with an appropriate sampling rate is often a trade-off between performance and economy. The influence of sampling rates on the neutron-gamma Pulse Shape Discrimination (PSD) with a solid stilbene scintillator coupled to a Silicon Photomultiplier was investigated in this work. Sampling rates from 125MSPS to 2GSPS from a 10-bit digitizer were used to collect detector pulses produced by the interactions of a Cf-252 source. Due to the decreased signal-to-noise ratio (SNR), the PSD performance degraded with reduced sampling rates. The reason of PSD performance degradation was discussed. Then, an efficient combination of filtering and digital signal processing (DSP) was then applied to suppress the timing noise and electronic background noise. The results demonstrate an improved PSD performance especially at low sampling rates, down to 125MSPS. Using filtering and DSP, the ascribed Figure of Merit (FOM) at 125keV ee (± 10keV ee ) increased from 0.95 to 1.02 at 125MSPS. At 300keV ee and above, all the FOMs are better than 2.00. Our study suggests that 250MSPS is a good enough sampling rate for neutron-gamma discrimination in this system in order to be sensitive to neutrons at and above ~ 125keV ee . Copyright © 2017 Elsevier Ltd. All rights reserved.

A laboratory assessment of the Waveband Integrated Bioaerosol Sensor (WIBS-4) using individual samples of pollen and fungal spore material

Science.gov (United States)

Healy, David A.; O'Connor, David J.; Burke, Aoife M.; Sodeau, John R.

2012-12-01

A Bioaerosol sensing instrument referred to as WIBS-4, designed to continuously monitor ambient bioaerosols on-line, has been used to record a multiparameter “signature” from each of a number of Primary Biological Aerosol Particulate (PBAP) samples found in air. These signatures were obtained in a controlled laboratory environment and are based on the size, asymmetry (“shape”) and auto-fluorescence of the particles. Fifteen samples from two separate taxonomic ranks (kingdoms), Plantae (×8) and Fungi (×7) were individually introduced to the WIBS-4 for measurement along with two non-fluorescing chemical solids, common salt and chalk. Over 2000 individual-particle measurements were recorded for each sample type and the ability of the WIBS spectroscopic technique to distinguish between chemicals, pollen and fungal spore material was examined by identifying individual PBAP signatures. The results obtained show that WIBS-4 could potentially be a very useful analytical tool for distinguishing between natural airborne PBAP samples, such as the fungal spores and may potentially play an important role in detecting and discriminating the toxic fungal spore, Aspergillus fumigatus, from others in real-time. If the sizing range of the commercial instrument was customarily increased and permitted to operate simultaneously in its two sizing ranges, pollen and spores could potentially be discriminated between. The data also suggest that the gain setting sensitivity on the detector would also have to be reduced by a factor >5, to routinely detect, in-range fluorescence measurements for pollen samples.

Influence of Spirituality and Modesty on Acceptance of Self-Sampling for Cervical Cancer Screening.

Directory of Open Access Journals (Sweden)

Eileen O Dareng

Full Text Available Whereas systematic screening programs have reduced the incidence of cervical cancer in developed countries, the incidence remains high in developing countries. Among several barriers to uptake of cervical cancer screening, the roles of religious and cultural factors such as modesty have been poorly studied. Knowledge about these factors is important because of the potential to overcome them using strategies such as self-collection of cervico-vaginal samples. In this study we evaluate the influence of spirituality and modesty on the acceptance of self-sampling for cervical cancer screening.We enrolled 600 participants in Nigeria between August and October 2014 and collected information on spirituality and modesty using two scales. We used principal component analysis to extract scores for spirituality and modesty and logistic regression models to evaluate the association between spirituality, modesty and preference for self-sampling. All analyses were performed using STATA 12 (Stata Corporation, College Station, Texas, USA.Some 581 (97% women had complete data for analysis. Most (69% were married, 50% were Christian and 44% were from the south western part of Nigeria. Overall, 19% (110/581 of the women preferred self-sampling to being sampled by a health care provider. Adjusting for age and socioeconomic status, spirituality, religious affiliation and geographic location were significantly associated with preference for self-sampling, while modesty was not significantly associated. The multivariable OR (95% CI, p-value for association with self-sampling were 0.88 (0.78-0.99, 0.03 for spirituality, 1.69 (1.09-2.64, 0.02 for religious affiliation and 0.96 (0.86-1.08, 0.51 for modesty.Our results show the importance of taking cultural and religious beliefs and practices into consideration in planning health interventions like cervical cancer screening. To succeed, public health interventions and the education to promote it must be related to the

Visual search for tropical web spiders: the influence of plot length, sampling effort, and phase of the day on species richness.

Science.gov (United States)

Pinto-Leite, C M; Rocha, P L B

2012-12-01

Empirical studies using visual search methods to investigate spider communities were conducted with different sampling protocols, including a variety of plot sizes, sampling efforts, and diurnal periods for sampling. We sampled 11 plots ranging in size from 5 by 10 m to 5 by 60 m. In each plot, we computed the total number of species detected every 10 min during 1 hr during the daytime and during the nighttime (0630 hours to 1100 hours, both a.m. and p.m.). We measured the influence of time effort on the measurement of species richness by comparing the curves produced by sample-based rarefaction and species richness estimation (first-order jackknife). We used a general linear model with repeated measures to assess whether the phase of the day during which sampling occurred and the differences in the plot lengths influenced the number of species observed and the number of species estimated. To measure the differences in species composition between the phases of the day, we used a multiresponse permutation procedure and a graphical representation based on nonmetric multidimensional scaling. After 50 min of sampling, we noted a decreased rate of species accumulation and a tendency of the estimated richness curves to reach an asymptote. We did not detect an effect of plot size on the number of species sampled. However, differences in observed species richness and species composition were found between phases of the day. Based on these results, we propose guidelines for visual search for tropical web spiders.

Measure the constituents of geological samples by XRF intensity influence coefficient method

International Nuclear Information System (INIS)

Dai Zhenlin; Ge Liangquan; Cheng Feng; Zhang Qingxian

2008-01-01

The elements of some ore samples (including primary ores in the mine) have been measured by using the Si-PIN detector and the portable high energy resolution XRF analyzer with an embedded computer constituting the intensity correction model of influence coefficient method. By comparing to the result by chemical analysis, the conclusion could be made as follows: the maximal relative error of the content of the element Fe with the content between 20% to 55% is not more than 4.74%, the maximal relative error of the content of the element Cu with the content between 182ppm to 2400ppm is not more than 24. 70% and not more than 7.46% with the content between 2400ppm to 3600ppm, the maximal relative error of the content of the element Zn with the content between 556ppm to 3200ppm is not more than 25. 93% and not more than 4.74% with the content between 3200ppm to 21600ppm, the maximal relative error of the content of the element Pb with the content between 5900ppm to 204200ppm is not more than 23.80% and not more than 13.79% with the content between 204200ppm to 511200ppm. In this way, this model could overcome the influence of matrix effect from base material components commendably and guide the work of mineral beneficiation in the mine effectively. (authors)

Characterization of citrus pectin samples extracted under different conditions: influence of acid type and pH of extraction

Science.gov (United States)

Kaya, Merve; Sousa, António G.; Crépeau, Marie-Jeanne; Sørensen, Susanne O.; Ralet, Marie-Christine

2014-01-01

Background and Aims Pectin is a complex macromolecule, the fine structure of which is influenced by many factors. It is used as a gelling, thickening and emulsifying agent in a wide range of applications, from food to pharmaceutical products. Current industrial pectin extraction processes are based on fruit peel, a waste product from the juicing industry, in which thousands of tons of citrus are processed worldwide every year. This study examines how pectin components vary in relation to the plant source (orange, lemon, lime, grapefruit) and considers the influence of extraction conditions on the chemical and macromolecular characteristics of pectin samples. Methods Citrus peel (orange, lemon, lime and grapefruit) from a commercial supplier was used as raw material. Pectin samples were obtained on a bulk plant scale (kilograms; harsh nitric acid, mild nitric acid and harsh oxalic acid extraction) and on a laboratory scale (grams; mild oxalic acid extraction). Pectin composition (acidic and neutral sugars) and physicochemical properties (molar mass and intrinsic viscosity) were determined. Key Results Oxalic acid extraction allowed the recovery of pectin samples of high molecular weight. Mild oxalic acid-extracted pectins were rich in long homogalacturonan stretches and contained rhamnogalacturonan I stretches with conserved side chains. Nitric acid-extracted pectins exhibited lower molecular weights and contained rhamnogalacturonan I stretches encompassing few and/or short side chains. Grapefruit pectin was found to have short side chains compared with orange, lime and lemon. Orange and grapefruit pectin samples were both particularly rich in rhamnogalacturonan I backbones. Conclusions Structural, and hence macromolecular, variations within the different citrus pectin samples were mainly related to their rhamnogalacturonan I contents and integrity, and, to a lesser extent, to the length of their homogalacturonan domains. PMID:25081519

The influence of target and sample properties on nuclear data measurements

International Nuclear Information System (INIS)

Okamoto, K.

1988-10-01

The IAEA Advisory Group Meeting (AGM) on The Influence of Target and Sample Properties on Nuclear Data Measurements was held at the Gesellschaft fuer Schwerionenforschung mbH, Darmstadt, Federal Republic of Germany, during the week 5-9 September 1988. The AGM (hereafter ''Meeting'') was held concurrently during the 14th World Conference (hereafter ''Conference'') of the International Nuclear Target Development Society (INTDS) in co-operation with the IAEA-International Nuclear Data Committee (INDC). The Meeting's special sessions (5th, 7th and 9th September 1988) were held to review and prepare the summary of the papers presented to the Conference and recommendations on the objectives of the AGM. The contributed papers to the Conference are to be published in the Journal Nuclear Instruments and Methods in Physical Research. The contributed notes to the Meeting's special sessions together with the summary of the contributed papers by the Agency's invitees and the discussions during the Meeting's special sessions and the recommendations are issued in this report. (author). Refs, figs and tabs

Fractures and Rock Mechanics, Phase 1

DEFF Research Database (Denmark)

Havmøller, Ole; Krogsbøll, Anette

1997-01-01

The main objectives of the project are to combine geological description of fractures, chalk types and rock mechanical properties, and to investigate whether the chosen outcrops can be used as analogues to reservoir chalks. Five chalk types, representing two outcrop localities: Stevns...

Mechanisms and interaction phenomena influencing releases in a low- and medium-level waste disposal system

International Nuclear Information System (INIS)

Brodersen, K.; Nilsson, K.

1991-01-01

The report covers work done 1986-1990 at Riso National Laboratory as part of the third EC Research Programme on Radioactive Waste Management. The report is divided into three parts: 1) Waste product characterization: - leaching and volume stability of cemented ion-exchange resins. - Hydroscopic properties of cemented and bituminized radioactive waste. - Water uptake and swelling of bituminized waste, water migration in bitumen membranes and measurements of swelling pressures. - Ageing of bituminized products. 2) Barrier material properties: - The influence of the pore structure in concrete on the hydraulic transport of water and ions through concrete barriers was investigated - Healing of cracks in concrete barriers by precipitation of calcium carbonate was demonstrated experimentally - Transport of components between two thin plates of cement paste with different composition stored together in water - The structure of degraded cement paste was studied using SANS (small angle neutron scattering). 3) Interaction phenomena: - Integral experiments with migration of radioisotopes from cemented waste through barriers made from kaolin, chalk or concrete were made under different external conditions. 51 figs., 15 tabs., 25 refs

Modelling of N2O Reduction in a Circulating Fluidized Bed Boiler

DEFF Research Database (Denmark)

Johnsson, Jan Erik; Åmand, Lars Erik; Dam-Johansen, Kim

1996-01-01

The addition of limestone for sulphur retention in Fluidized Bed Combustion (FBC) has been observed to influence the emission of N2O, and in many cases a lower emission was observed. The catalytic activity of a Danish limestone (Stevns Chalk) for decomposition of N2O in a laboratory fixed bed qua...

Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

Directory of Open Access Journals (Sweden)

Brunatto S.F.

2001-01-01

Full Text Available The present work reports an investigation of the influence of the radial spacing between cathodes on the iron sintering process by hollow cathode electrical discharge, with surface enrichment of the alloying elements Cr and Ni. Pressed cylindrical samples of 9.5 mm diameter and density of 7.0 ± 0.1 g/cm³ were prepared by compaction of Ancorsteel 1000C iron powder. These samples, constituting the central cathode, were positioned concentrically in the interior of an external cathode machined from a tube of stainless steel AISI 310 (containing: 25% Cr, 16% Ni, 1.5% Mn, 1.5% Si, 0.03% C and the remainder Fe. Sintering was done at 1150 °C, for 120 min, utilizing radial spacings between the central and hollow cathodes of 3, 6 and 9 mm and a gas mixture of 80% Ar and 20% H2, with a flow rate of 5 cm³/s at a pressure of 3 Torr. The electric discharge was generated using a pulsed voltage power source, with a period of 200 mus. The radial spacing had only a slight influence on the quantity of atoms of alloying elements deposited and diffused on the surface of the sample. Analysis with a microprobe showed the presence of chrome (up to 4.0% and nickel (up to 3.0%, in at. % at the surface of the samples. This surface enrichment can be attributed to the mechanism of sputtering of the metallic atoms present in the external cathode, with the deposition of these elements on the sample surface and consequent diffusion within the sample.

Results of detailed ground geophysical surveys for locating and differentiating waste structures in waste management area 'A' at Chalk River Laboratories, Ontario

Energy Technology Data Exchange (ETDEWEB)

Tomsons, D.K.; Street, P.J.; Lodha, G.S

1999-07-01

Waste Management Area 'A' (WMA 'A'), located in the outer area of the Chalk River Laboratories (CRL) was in use as a waste burial site from 1946 to 1955. Waste management structures include debris-filled trenches, concrete bunkers and miscellaneous contaminated solid materials, and ditches and pits used for liquid dispersal. In order to update historical records, it was proposed to conduct detailed ground geophysical surveys to define the locations of waste management structures in WMA 'A', assist in planning of the drilling and sampling program to provide ground truth for the geophysics investigation and to predict the nature and locations of unknown/undefined shallow structures. A detailed ground geophysical survey grid was established with a total of 127 grid lines, oriented NNE and spaced one metre apart. The geophysical surveys were carried out during August and September, 1996. The combination of geophysical tools used included the Geonics EM61 metal detector, the GSM-19 magnetometer/gradiometer and a RAMAC high frequency ground penetrating radar system. The geophysical surveys were successful in identifying waste management structures and in characterizing to some extent, the composition of the waste. The geophysical surveys are able to determine the presence of most of the known waste management structures, especially in the western and central portions of the grid which contain the majority of the metallic waste. The eastern portion of the grid has a completely different geophysical character. While historical records show that trenches were dug, they are far less evident in the geophysical record. There is clear evidence for a trench running between lines 30E and 63E at 70 m. There are indications from the radar survey of other trench-like structures in the eastern portion. EM61 data clearly show that there is far less metallic debris in the eastern portion. The geophysical surveys were also successful in identifying

TASCC newsletter volume 9 no. 4

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1995-04-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this April issue of TASCC is an update of the facility, analysis of Chernobyl samples, staff changes, Internet availability and a listing of April`s experiments. 1 fig.

Elementary characterization of samples of Portland cement, natural gypsum and phosphogypsum mortars from Brazil

Energy Technology Data Exchange (ETDEWEB)

Narloch, Danielle Cristine; Paschuk, Sergei Anatolyevich; Corrêa, Janine Nicolosi; Torres, Catarina Alzira Peddis; Mazer, Wellington; Macioski, Gustavo [Universidade Tecnologica Federal do Parana (UTFPR), PR (Brazil); Lara, Alessandro [Universidade de Sao Paulo (USP), SP (Brazil). Departamento de Fisica; Casali, Juliana Machado, E-mail: janine_nicolosi@hotmail.com, E-mail: alellara@hotmail.com, E-mail: jucasali@gmail.com [Instituto Federal de Santa Catarina (IFSC), Florianópolis, SC (Brazil)

2017-07-01

Portland cement, the basic ingredient of concrete and is manufactured by crushing, milling and proportioning limestone, sand, clay, iron ore and secondary materials such as shells, chalk or marl combined with shale slate or blast furnace slag, fly ash, gypsum, phosphogypsum, and some others. Evaluating the physical and mineralogical characteristics of the cement and its chemical composition is essential to establish the quality of the product. Therefore, the objective of this work was to characterize and quantify the most common chemical elements in the samples of Brazilian Portland cement, natural gypsum, and phosphogypsum mortars by means of X-ray dispersive energy spectroscopy (EDXRF), as well as to evaluate the strength of these mortars. For analysis of the compressive strength, initially prepared samples were submitted to a destructive mechanical test. Subsequently samples were milled and compacted to form thin tablets, which were submitted to the EDXRF analysis. The qualitative and quantitative analyzes showed that for phosphogypsum mortar the largest mass fractions were found of 49.8±2.5% (Si), 24.66±0.96% (S) and 22.10±0.42% (Ca). For gypsum mortar those values were found of 43.41±0.45% (Ca), 33.8 ± 0.8% (S) and 18.9±1.2% (Si), respectively; and for Portland cement mortar, the predominant elements in those samples have the mass fractions of 64.20±0.52% (Ca) and 27.3±1.5% (Si). The results showed that obtained values of mass fraction of the elements Si, S, K, Ca, Ti, Fe are in rather good agreement with quantities indicated for manufacture. Besides, gypsum and phosphogypsum presented almost the same composition and compressive strength. (author)

Elementary characterization of samples of Portland cement, natural gypsum and phosphogypsum mortars from Brazil

International Nuclear Information System (INIS)

Narloch, Danielle Cristine; Paschuk, Sergei Anatolyevich; Corrêa, Janine Nicolosi; Torres, Catarina Alzira Peddis; Mazer, Wellington; Macioski, Gustavo; Lara, Alessandro

2017-01-01

Portland cement, the basic ingredient of concrete and is manufactured by crushing, milling and proportioning limestone, sand, clay, iron ore and secondary materials such as shells, chalk or marl combined with shale slate or blast furnace slag, fly ash, gypsum, phosphogypsum, and some others. Evaluating the physical and mineralogical characteristics of the cement and its chemical composition is essential to establish the quality of the product. Therefore, the objective of this work was to characterize and quantify the most common chemical elements in the samples of Brazilian Portland cement, natural gypsum, and phosphogypsum mortars by means of X-ray dispersive energy spectroscopy (EDXRF), as well as to evaluate the strength of these mortars. For analysis of the compressive strength, initially prepared samples were submitted to a destructive mechanical test. Subsequently samples were milled and compacted to form thin tablets, which were submitted to the EDXRF analysis. The qualitative and quantitative analyzes showed that for phosphogypsum mortar the largest mass fractions were found of 49.8±2.5% (Si), 24.66±0.96% (S) and 22.10±0.42% (Ca). For gypsum mortar those values were found of 43.41±0.45% (Ca), 33.8 ± 0.8% (S) and 18.9±1.2% (Si), respectively; and for Portland cement mortar, the predominant elements in those samples have the mass fractions of 64.20±0.52% (Ca) and 27.3±1.5% (Si). The results showed that obtained values of mass fraction of the elements Si, S, K, Ca, Ti, Fe are in rather good agreement with quantities indicated for manufacture. Besides, gypsum and phosphogypsum presented almost the same composition and compressive strength. (author)

How much will afforestation of former cropland influence soil C stocks? A synthesis of paired sampling, chronosequence sampling and repeated sampling studies

Science.gov (United States)

Vesterdal, Lars; Hansen, K.; Stupak, I.; Don, Axel; Poeplau, C.; Leifeld, Jens; van Wesemael, Bas

2010-05-01

The need for documentation of land-use change effects on soil C is high on the agenda in most signatory countries to the Kyoto Protocol. Large land areas in Europe have experienced land-use change from cropland to forest since 1990 by direct afforestation as well as abandonment and regrowth of marginally productive cropland. Soil C dynamics following land-use change remain highly uncertain due to a limited number of available studies and due to influence of interacting factors such as land use history, soil type, and climate. Common approaches for estimation of potential soil C changes following land-use change are i) paired sampling of plots with a long legacy of different land uses, ii) chronosequence studies of land-use change, and lastly iii) repeated sampling of plots subject to changed land use. This paper will synthesize the quantitative effects of cropland afforestation on soil C sequestration based on all three approaches and will report on related work within Cost 639. Paired plots of forest and cropland were used to study the general differences between soil C stocks in the two land uses. At 27 sites in Denmark distributed among different regions and soil types forest floor and mineral soil were sampled in and around soil pits. Soil C stocks were higher in forest than cropland (mean difference 22 Mg C ha-1 to 1 m depth). This difference was caused solely by the presence of a forest floor in forests; mineral soil C stocks were similar (108 vs. 109 Mg C ha-1) in the two land uses regardless of soil type and the soil layers considered. The chronosequence approach was employed in the AFFOREST project for evaluation of C sequestration in biomass and soils following afforestation of cropland. Two oak (Quercus robur) and four Norway spruce (Picea abies) afforestation chronosequences (age range 1 to 90 years) were studied in Denmark, Sweden and the Netherlands. Forest floor and mineral soil (0-25 cm) C contents were as a minimum unchanged and in most cases there

Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama -- Year 2. Annual report, March 1997--March 1998

Energy Technology Data Exchange (ETDEWEB)

Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.

1998-09-01

Gilbertown Field is the oldest oil field in Alabama and has produced oil from fractured chalk of the Cretaceous Selma Group and glauconitic sandstone of the Eutaw Formation. Nearly all of Gilbertown Field is still in primary recovery, although waterflooding has been attempted locally. The objective of this project is to analyze the geologic structure and burial history of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas in order to suggest ways in which oil recovery can be improved. Indeed, the decline of oil production to marginally economic levels in recent years has made this type of analysis timely and practical. Key technical advancements being sought include understanding the relationship of requisite strain to production in Gilbertown reservoirs, incorporation of synsedimentary growth factors into models of area balance, quantification of the relationship between requisite strain and bed curvature, determination of the timing of hydrocarbon generation, and identification of the avenues and mechanisms of fluid transport.

Factors influencing safety in a sample of marked pedestrian crossings selected for safety inspections in the city of Oslo.

Science.gov (United States)

Elvik, Rune; Sørensen, Michael W J; Nævestad, Tor-Olav

2013-10-01

This paper reports an analysis of factors influencing safety in a sample of marked pedestrian crossings in the city of Oslo, Norway. The sample consists of 159 marked pedestrian crossings where a total of 316 accidents were recorded during a period of five years. The crossings were selected for inspection because of they were, for various reasons, regarded as sub-standard. The sample of crossings is therefore not representative of all pedestrian crossings in Oslo. Factors influencing the number of accidents were studied by means of negative binomial regression. Factors that were studied included the volume of pedestrians and vehicles, the number of traffic lanes at the crossing, the location of the crossing (midblock or junction), the type of traffic control, the share of pedestrians using the crossing and the speed of approaching vehicles. The analysis confirmed the presence of a "safety-in-numbers" effect, meaning that an increase in the number of pedestrians is associated with a lower risk of accident for each pedestrian. Crossings located in four-leg junctions or roundabouts had more accidents than crossings located in three-leg junctions or on sections between junctions. A high share of pedestrians crossing the road outside the marked crossing was associated with a high number of accidents. Increased speed was associated with an increased number of accidents. Copyright © 2013 Elsevier Ltd. All rights reserved.

The influence of maternal vulnerability and parenting stress on chronic pain in adolescents in a general population sample: the TRAILS study

NARCIS (Netherlands)

Passchier, J.; Darlington, A.S.; Verhulst, F.C.; De Winter, A.F.; Ormel, J.; Hunfeld, J.A.

2012-01-01

Investigating possible psychosocial predictors of unexplained chronic pain in adolescents is crucial in understanding its development and prevention. A general population sample of adolescents (n = 2230) from the TRAILS cohort study was investigated longitudinally to assess the influence of maternal

The influence of maternal vulnerability and parenting stress on chronic pain in adolescents in a general population sample : The TRAILS study

NARCIS (Netherlands)

Darlington, A-S. E.; Verhulst, F. C.; De Winter, A. F.; Ormel, J.; Passchier, J.; Hunfeld, J. A. M.

Investigating possible psychosocial predictors of unexplained chronic pain in adolescents is crucial in understanding its development and prevention. A general population sample of adolescents (n = 2230) from the TRAILS cohort study was investigated longitudinally to assess the influence of maternal

The Influence of Emotional Inhibition on Intrusive Thoughts in a Non-Clinical Sample

Directory of Open Access Journals (Sweden)

Zahra Salehzadeh Einabad

2017-06-01

Full Text Available Background Given the studies insisting on the impacts of cultural issues on the emotion regulation strategies in eastern cultures and lack of study on the effects of emotional inhibition in our culture, this research aimed to investigate the influences of emotional inhibition on intrusive thoughts in non-clinical sample. Methods A quasi-experimental design was adopted with 45 participants that were randomly assigned to 2 groups (emotional inhibition and control groups. Participants which were selected according to cluster sampling answered to some questionnaires, including depression, general health, and emotion regulation. Then, a clip and a related instruction were presented for each group. They were asked to perform according to instruction after watching movie and tick on a paper whenever the thoughts of movie come to their mind. Data were analyzed using t test in SPSS-23. Results There are not significant differences between groups in terms of mood, emotion regulation, depression, and general health in the pre-test. Similarly, results indicated that there is not a significant differences between groups. Conclusions This research showed that the usefulness of emotional inhibition depends on the culture. In fact, in Eastern cultures, using emotion regulation strategies such as suppression and emotional inhibition are common so that avoidance is a short term and useful emotion regulation mechanism.

Influence of Fasting Status and Sample Preparation on Metabolic Biomarker Measurements in Postmenopausal Women.

Science.gov (United States)

Murphy, Neil; Falk, Roni T; Messinger, Diana B; Pollak, Michael; Xue, Xiaonan; Lin, Juan; Sgueglia, Robin; Strickler, Howard D; Gaudet, Mia M; Gunter, Marc J

2016-01-01

Epidemiologic data linking metabolic markers-such as insulin, insulin-like growth factors (IGFs)-and adipose tissue-derived factors with cancer are inconsistent. Between-study differences in blood collection protocols, in particular participant's fasting status, may influence measurements. We investigated the impact of fasting status and blood sample processing time on components of the insulin/IGF axis and in adipokines in a controlled feeding study of 45 healthy postmenopausal-women aged 50-75 years. Fasting blood samples were drawn (T0), after which subjects ate a standardized breakfast; subsequent blood draws were made at 1 hour (T1), 3 hours (T3), and 6 hours (T6) after breakfast. Serum samples were assayed for insulin, C-peptide, total- and free-IGF-I, IGF-binding protein [BP]-1 and -3, total and high molecular weight (HMW)-adiponectin, retinol binding protein-4, plasminogen activator inhibitor (PAI)-1, and resistin. Insulin and C-peptide levels followed similar postprandial trajectories; intra-class correlation coefficients [ICC] for insulin = 0.75, (95%CI:0.64-0.97) and C-peptide (ICC = 0.66, 95%CI:0.54-0.77) were similarly correlated in fasting (Spearman correlation, r = 0.78, 95%CI:0.64-0.88) and postprandial states (T1, r = 0.77 (95%CI: 0.62-0.87); T3,r = 0.78 (95%CI: 0.63-0.87); T6,r = 0.77 (95%CI: 0.61-0.87)). Free-IGF-I and IGFBP-1 levels were also affected by fasting status, whereas total-IGF-I and IGFBP-3 levels remained unchanged. Levels of adipokines were largely insensitive to fasting status and blood sample processing delays. Several components of the insulin/IGF axis were significantly impacted by fasting state and in particular, C-peptide levels were substantially altered postprandially and in a similar manner to insulin.

The influence of freezer storage of urine samples on the BONN-Risk-Index for calcium oxalate crystallization.

Science.gov (United States)

Laube, Norbert; Zimmermann, Diana J

2004-01-01

This study was performed to quantify the effect of a 1-week freezer storage of urine on its calcium oxalate crystallization risk. Calcium oxalate is the most common urinary stone material observed in urolithiasis patients in western and affluent countries. The BONN-Risk-Index of calcium oxalate crystallization risk in human urine is determined from a crystallization experiment performed on untreated native urine samples. We tested the influence of a 1-week freezing on the BONN-Risk-Index value as well as the effect of the sample freezing on the urinary osmolality. In vitro crystallization experiments in 49 native urine samples from stone-forming and non-stone forming individuals were performed in order to determine their calcium oxalate crystallization risk according to the BONN-Risk-Index approach. Comparison of the results derived from original sample investigations with those obtained from the thawed aliquots by statistical evaluation shows that i) no significant deviation from linearity between both results exists and ii) both results are identical by statistical means. This is valid for both, the BONN-Risk-Index and the osmolality data. The differences in the BONN-Risk-Index results of both procedures of BONN-Risk-Index determination, however, exceed the clinically acceptable difference. Thus, determination of the urinary calcium oxalate crystallization risk from thawed urine samples cannot be recommended.

Influence of sampling properties of fast-waveform digitizers on neutron−gamma-ray, pulse-shape discrimination for organic scintillation detectors

International Nuclear Information System (INIS)

Flaska, Marek; Faisal, Muhammad; Wentzloff, David D.; Pozzi, Sara A.

2013-01-01

One of the most important questions to be answered with regard to digital pulse-shape discrimination (PSD) systems based on organic scintillators is: What sampling properties are required for a fast-waveform digitizer used for digitizing neutron/gamma-ray pulses, while an accurate PSD is desired? Answering this question is the main objective of this paper. Specifically, the paper describes the influence of the resolution and sampling frequency of a waveform digitizer on the PSD performance of organic scintillators. The results presented in this paper are meant to help the reader choosing a waveform digitizer with appropriate bit resolution and sampling frequency. The results presented here show that a 12-bit, 250-MHz digitizer is a good choice for applications that require good PSD performance. However, when more accurate PSD performance is the main requirement, this paper presents PSD figures of merit to qualify the impact of further increasing either sampling frequency or resolution of the digitizer

An integrated modelling and multicriteria analysis approach to managing nitrate diffuse pollution: 2. A case study for a chalk catchment in England.

Science.gov (United States)

Koo, B K; O'Connell, P E

2006-04-01

The site-specific land use optimisation methodology, suggested by the authors in the first part of this two-part paper, has been applied to the River Kennet catchment at Marlborough, Wiltshire, UK, for a case study. The Marlborough catchment (143 km(2)) is an agriculture-dominated rural area over a deep chalk aquifer that is vulnerable to nitrate pollution from agricultural diffuse sources. For evaluation purposes, the catchment was discretised into a network of 1 kmx1 km grid cells. For each of the arable-land grid cells, seven land use alternatives (four arable-land alternatives and three grassland alternatives) were evaluated for their environmental and economic potential. For environmental evaluation, nitrate leaching rates of land use alternatives were estimated using SHETRAN simulations and groundwater pollution potential was evaluated using the DRASTIC index. For economic evaluation, economic gross margins were estimated using a simple agronomic model based on nitrogen response functions and agricultural land classification grades. In order to see whether the site-specific optimisation is efficient at the catchment scale, land use optimisation was carried out for four optimisation schemes (i.e. using four sets of criterion weights). Consequently, four land use scenarios were generated and the site-specifically optimised land use scenario was evaluated as the best compromise solution between long term nitrate pollution and agronomy at the catchment scale.

Influence of Plastic Deformation of Steel Samples on the Fast electron Backscattering

International Nuclear Information System (INIS)

Sierra Trujillo, J. X.; Herrera Palma, V.; Desdin Garcia, L. F.; Codorniu Pujals, D.

2013-01-01

A considerable fraction of a fast electron beam incident on a target is scattered in backward direction. It is a very complex process involving electron - nucleus and electron - electron collisions. The fraction of backscattered electrons is described by a parameterization as a function of the atomic number and energy of the incident electrons. In such approaches the possible influence of the material structure is not taken into account. In this paper, the behavior of the 90 Sr/ 90 Y backscattered electrons from 08JuA and 15GJuT steel strained samples is investigated. A clear dependence between the degree of plastic deformation and the fraction of backscattered electrons was observed. This relationship is explained by the interaction of electrons with the dislocations in the material, whose density depends on the magnitude of the strain in the plastic region. On the basis of a simple model for describing this interaction, a mathematical expression is obtained for the relationship between the fraction of backscattered electrons and the degree of deformation. (Author)

Normal and Reversed-Phase Thin Layer Chromatography of Green Leaf Extracts

Science.gov (United States)

Sjursnes, Birte Johanne; Kvittingen, Lise; Schmid, Rudolf

2015-01-01

Introductory experiments of chromatography are often conducted by separating colored samples, such as inks, dyes, and plant extracts, using filter paper, chalk, or thin layer chromatography (TLC) plates with various solvent systems. Many simple experiments have been reported. The relationship between normal chromatography and reversed-phase…

Upper Campanian–Maastrichtian nannofossil biostratigraphy and high-resolution carbon-isotope stratigraphy of the Danish Basin

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph; Harlou, Rikke; Schovsbo, Niels

2012-01-01

High-resolution carbon isotope stratigraphy of the upper Campanian – Maastrichtian is recorded in the Boreal Realm from a total of 1968 bulk chalk samples of the Stevns-1 core, eastern Denmark. Isotopic trends are calibrated by calcareous nannofossil bio-events and are correlated with a lower...

mHealth Series: Factors influencing sample size calculations for mHealth–based studies – A mixed methods study in rural China

Science.gov (United States)

van Velthoven, Michelle Helena; Li, Ye; Wang, Wei; Du, Xiaozhen; Chen, Li; Wu, Qiong; Majeed, Azeem; Zhang, Yanfeng; Car, Josip

2013-01-01

Background An important issue for mHealth evaluation is the lack of information for sample size calculations. Objective To explore factors that influence sample size calculations for mHealth–based studies and to suggest strategies for increasing the participation rate. Methods We explored factors influencing recruitment and follow–up of participants (caregivers of children) in an mHealth text messaging data collection cross–over study. With help of village doctors, we recruited 1026 (25%) caregivers of children under five out of the 4170 registered. To explore factors influencing recruitment and provide recommendations for improving recruitment, we conducted semi–structured interviews with village doctors. Of the 1014 included participants, 662 (65%) responded to the first question about willingness to participate, 538 (53%) responded to the first survey question and 356 (35%) completed the text message survey. To explore factors influencing follow–up and provide recommendations for improving follow–up, we conducted interviews with participants. We added views from the researchers who were involved in the study to contextualize the findings. Results We found several factors influencing recruitment related to the following themes: experiences with recruitment, village doctors’ work, village doctors’ motivations, caregivers’ characteristics, caregivers’ motivations. Village doctors gave several recommendations for ways to recruit more caregivers and we added our views to these. We found the following factors influencing follow–up: mobile phone usage, ability to use mobile phone, problems with mobile phone, checking mobile phone, available time, paying back text message costs, study incentives, subjective norm, culture, trust, perceived usefulness of process, perceived usefulness of outcome, perceived ease of use, attitude, behavioural intention to use, and actual use. From our perspective, factors influencing follow–up were: different

Groundwater quality in alluvial and prolluvial areas under the influence of irrigated agriculture activities.

Science.gov (United States)

Kovacevik, Biljana; Boev, Blazo; Panova, Vesna Zajkova; Mitrev, Sasa

2016-12-05

The aim of this study was to investigate the groundwater pollution from alluvial aquifers lying under surface agriculture activities in two geologically different areas: alluvial and prolluvial. The groundwater in investigated areas is neutral to alkaline (pH 7.05-8.45), and the major dissolved ions are bicarbonate and calcium. Groundwater samples from the alluvial area are characterized by nitrate concentration above the national maximum concentration limit (MCL) at 20.5% of samples [mean value (Me) 6.31 mg/L], arsenic concentrations greater than national MCL at 35.6% of investigated samples (Me 12.12 µg/L) and elevated concentrations of iron (Me 202.37 µg/L) and manganese (Me 355.22 µg/L) at 22.7% and 81% of investigated samples, respectively. Groundwater samples from the prolluvial area did not show significantly elevated concentrations of heavy metals, but the concentration of nitrate was considerably higher (Me 65.06 mg/L). Factor analysis positively correlates As with Mn and Fe, suggesting its natural origin. Nitrate was found in positive correlation with SO 4 2- and Ni but in negative with NH 4 + , suggesting its anthropogenic origin and the relationship of these ions in the process of denitrification. The t-test analysis showed a significant difference between nitrate pollution of groundwater from alluvial and prolluvial areas. According to the chemical composition of groundwater, the process of denitrification is considered to be the main reason for the reduced presence of nitrate in the groundwater lying under alluvial deposits represented by chalk and sandstones. Denitrification in groundwater lying under prolluvial deposits represented by magmatic and metamorphic rock formations was not observed.

Influence of Sampling Practices on the Appearance of DNA Image Histograms of Prostate Cells in FNAB Samples

Directory of Open Access Journals (Sweden)

Abdelbaset Buhmeida

1999-01-01

Full Text Available Twenty‐one fine needle aspiration biopsies (FNAB of the prostate, diagnostically classified as definitely malignant, were studied. The Papanicolaou or H&E stained samples were destained and then stained for DNA with the Feulgen reaction. DNA cytometry was applied after different sampling rules. The histograms varied according to the sampling rule applied. Because free cells between cell groups were easier to measure than cells in the cell groups, two sampling rules were tested in all samples: (i cells in the cell groups were measured, and (ii free cells between cell groups were measured. Abnormal histograms were more common after the sampling rule based on free cells, suggesting that abnormal patterns are best revealed through the free cells in these samples. The conclusions were independent of the applied histogram interpretation method.

Study on the influence of X-ray tube spectral distribution on the analysis of bulk samples and thin films: Fundamental parameters method and theoretical coefficient algorithms

International Nuclear Information System (INIS)

Sitko, Rafal

2008-01-01

Knowledge of X-ray tube spectral distribution is necessary in theoretical methods of matrix correction, i.e. in both fundamental parameter (FP) methods and theoretical influence coefficient algorithms. Thus, the influence of X-ray tube distribution on the accuracy of the analysis of thin films and bulk samples is presented. The calculations are performed using experimental X-ray tube spectra taken from the literature and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al. (X-Ray Spectrom. 14 (1985) 125-135), Ebel (X-Ray Spectrom. 28 (1999) 255-266), and Finkelshtein and Pavlova (X-Ray Spectrom. 28 (1999) 27-32). In this study, Fe-Cr-Ni system is selected as an example and the calculations are performed for X-ray tubes commonly applied in X-ray fluorescence analysis (XRF), i.e., Cr, Mo, Rh and W. The influence of X-ray tube spectra on FP analysis is evaluated when quantification is performed using various types of calibration samples. FP analysis of bulk samples is performed using pure-element bulk standards and multielement bulk standards similar to the analyzed material, whereas for FP analysis of thin films, the bulk and thin pure-element standards are used. For the evaluation of the influence of X-ray tube spectra on XRF analysis performed by theoretical influence coefficient methods, two algorithms for bulk samples are selected, i.e. Claisse-Quintin (Can. Spectrosc. 12 (1967) 129-134) and COLA algorithms (G.R. Lachance, Paper Presented at the International Conference on Industrial Inorganic Elemental Analysis, Metz, France, June 3, 1981) and two algorithms (constant and linear coefficients) for thin films recently proposed by Sitko (X-Ray Spectrom. 37 (2008) 265-272)

Influence of sample temperature on the expansion dynamics and the optical emission of laser-induced plasma

Energy Technology Data Exchange (ETDEWEB)

Eschlböck-Fuchs, S.; Haslinger, M.J.; Hinterreiter, A.; Kolmhofer, P.; Huber, N. [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Rössler, R. [voestalpine Stahl GmbH, A-4031 Linz (Austria); Heitz, J. [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Pedarnig, J.D., E-mail: johannes.pedarnig@jku.at [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria)

2013-09-01

We investigate the influence of sample temperature on the dynamics and optical emission of laser induced plasma for various solid materials. Bulk aluminum alloy, silicon wafer, and metallurgical slag samples are heated to temperature T{sub S} ≤ 500 °C and ablated in air by Nd:YAG laser pulses (wavelength 1064 nm, pulse duration approx. 7 ns). The plasma dynamics is investigated by fast time-resolved photography. For laser-induced breakdown spectroscopy (LIBS) the optical emission of plasma is measured by Echelle spectrometers in combination with intensified CCD cameras. For all sample materials the temporal evolution of plume size and broadband plasma emission vary systematically with T{sub S}. The size and brightness of expanding plumes increase at higher T{sub S} while the mean intensity remains independent of temperature. The intensity of emission lines increases with temperature for all samples. Plasma temperature and electron number density do not vary with T{sub S}. We apply the calibration-free LIBS method to determine the concentration of major oxides in slag and find good agreement to reference data up to T{sub S} = 450 °C. The LIBS analysis of multi-component materials at high temperature is of interest for technical applications, e.g. in industrial production processes. - Highlights: • Size and emission of laser-induced plasma increase with sample temperature Ts. • Mean optical intensity of plasma is independent of Ts. • Plasma temperature and electron number density do not vary with Ts. • Major oxides in steel slag are quantified up to Ts = 450 °C. • Industrial steel slags are analyzed by calibration-free LIBS method.

Assessing inventories of past radioactive waste arisings at Chalk River Laboratories

International Nuclear Information System (INIS)

Csullog, G.W.; TerHuurne, M.A.; Miller, M.T.; Edwards, N.W.; Hulley, V.R.; McCann, D.J.

1998-01-01

Internationally, a great deal of progress has been made in improving the management of currently accumulating and anticipated future radioactive wastes. Progress includes improved waste collection, segregation, characterization and documentation in support of disposal facility licensing and operation. These improvements are not often very helpful for assessing the hazards of wastes collected prior to their implementation, since, internationally, historic radioactive wastes were not managed and documented according to today's methods. This paper provides an overview of Atomic Energy of Canada Limited's (AECL) unique approach to managing its currently accumulating, low-level radioactive wastes at Chalk River Laboratories (CRL) and it describes the novel method AECL-CRL has developed to assess its historic radioactive wastes. Instead of estimating the characteristics of current radioactive wastes on a package-by-package basis, process knowledge is used to infer the average characteristics of most wastes. This approach defers, and potentially avoids, the use of expensive analytical technologies to characterize wastes until a reasonable certainty is gained about their ultimate disposition (Canada does not yet have a licensed radioactive waste disposal facility). Once the ultimate disposition is decided, performance assessments determine if inference characterization is adequate or if additional characterization is required. This process should result in significant cost savings to AECL since expensive, resource-intensive, up-front characterization may not be required for low-impact wastes. In addition, as technological improvements take place, the unit cost of characterization usually declines, making it less expensive to perform any additional characterization for current radioactive wastes. The WIP-III data management system is used at CRL to 'warehouse' the average characteristics of current radioactive wastes. This paper describes how this 'warehouse of information

Snack and beverage consumption and preferences in a sample of Chinese children - Are they influenced by advertising?

Science.gov (United States)

Liu, Peng; Yu, Yang; King, Lesley; Li, Mu

2017-01-01

The consumption of unhealthy snack and beverages can lead to childhood obesity, which has become a major concern globally. Television food advertisements may influence children's snack and beverages preferences. This article aims to explore children's snack and beverage consumption habits; examine the extent of television advertising for non-core (energy-dense, nutrient poor) snack and beverages; and assess the influence of television advertising on children's snack and beverages preferences in Harbin, China. The study consisted of two components, a recall survey on the snack and beverage consumption and preferences of 9-11 years old school children; and recording snack and beverage advertisements on three popular television channels. Odds Ratio (OR) was used to estimate the likelihood of children selecting particular snack and beverages as their top three choices according to whether their preferences were influenced by television advertisements. The majority of children consumed non-core snacks (100%) and beverages (80%) in the four weeks prior to the survey. Nearly 40% of television food advertisements were for non-core snacks and beverages. Non-core snacks (OR of 1.13) and non-core beverages (OR of 1.23) were more likely chosen as children's top three snack/beverage choices, particularly, "puffed food and tubers" snack and carbonated beverages (OR of 1.31 and 1.45, respectively). The snack and beverage preferences appeared to be influenced by television advertisements in this sample of Chinese children, highlighting the potential health and nutritional value of policy to reduce advertising of non-core foods in China.

Electric dewatering and drying of fine-grained products; Elektrisk afvanding og toerring af finkornede produkter

Energy Technology Data Exchange (ETDEWEB)

Hansen, H.K.; Villumsen, A.

2001-07-01

The aim of the project was to elucidate four aspects related to using electric direct current to find an energy saving alternative to existing methods within dewatering of fine-grained products. The four aspects were a) electrophoresis forced sedimentation of chalk slurry, b) electro osmotic dewatering of chalk slurry, c) electro osmotic dewatering of agricultural chalk and d) electro osmotic dewatering of liquid organic wastes. (EHS)

Trace element content of precipitation in a remote area

International Nuclear Information System (INIS)

Merritt, W.F.

1976-01-01

Rain and snow, sampled over a period of 18 months at Chalk River Nuclear Laboratories, were analysed for 40 elements by thermal neutron activation analysis. Correlation analysis revealed that the elements detected could be divided into groups of similar behaviour. Storm tracks for the events sampled were obtained, but only generalizations as to the probable origin of the trace elements could be made. Deuterium content of the samples was not correlated with levels of trace elements. (author)

Determination of the detection limit and decision threshold for ionizing radiation measurements. Part 3: Fundamentals and application to counting measurements by high resolution gamma spectrometry, without the influence of sample treatment

International Nuclear Information System (INIS)

2000-01-01

This part of ISO 11929 addresses the field of ionizing radiation measurements in which events (in particular pulses) are counted by high resolution gamma spectrometry registrating a pulse-heights distribution (acquisition of a multichannel spectrum), for example on samples. It considers exclusively the random character of radioactive decay and of pulse counting and ignores all other influences (e.g. arising from sample treatment, weighing, enrichment or the instability of the test setup). It assumes that the distance of neighbouring peaks of gamma lines is not smaller than four times the full width half maximum (FWHM) of gamma line and that the background near to gamma line is nearly a straight line. Otherwise ISO 11929-1 or ISO 11929-2 should be used. ISO 11929 consists of the following parts, under the general title Determination of the detection limit and decision threshold for ionizing radiation measurements: Part 1: Fundamentals and application to counting measurements without the influence of sample treatment; Part 2: Fundamentals and application to counting measurements with the influence of sample treatment; Part 3: Fundamentals and application to counting measurements by high resolution gamma spectrometry, without the influence of sample treatment; Part 4: Fundamentals and application to measurements by use of linear scale analogue ratemeters, without the influence of sample treatment. This part of ISO 11929 was prepared in parallel with other International Standards prepared by WG2 (now WG 17): ISO 11932:1996, Activity measurements of solid materials considered for recycling, re-use or disposal as nonradioactive waste, and ISO 11929-1, ISO 11929-2 and ISO 11929-4, and is, consequently, complementary to these documents

Aerosol Formation during the Combustion of Straw with Addition of Sorbents

DEFF Research Database (Denmark)

Zeuthen, Frederik Jacob; Jensen, Peter Arendt; Jensen, Jørgen P.

2007-01-01

, calcium phosphate, Bentonite, ICA5000, and clay. The addition of chalk increased the aerosol mass concentration by 24%. Experiments in a laminar flow aerosol condenser with the six sorbents were carried out in the laboratory using a synthetic flue gas to avoid fluctuations in the alkali feeding......The influence of six sorbents on aerosol formation during the combustion of straw in a 100 MW boiler on a Danish power plant has been studied in full-scale. The following sorbents were studied: ammonium sulfate, monocalcium phosphate, Bentonite, ICA5000, clay, and chalk. Bentonite and ICA5000...... are mixtures of clay minerals and consist mainly of the oxides from Fe, Al, and Si. The straw used was Danish wheat and seed grass. Measurements were also made with increased flow of primary air. The experiments showed between 46% and 70% reduction in particle mass concentrations when adding ammonium sulfate...

Effective physiology teaching methods: from the perspective of first year MBBS students.

Science.gov (United States)

Nagothu, Rajani Santhakumari; Reddy Indla, Yogananda; Paluru, Rajesh

2016-01-01

Students who took admission in first year MBBS course used to study physiology, anatomy and biochemistry for one and half years. Since a decade the first year course duration was reduced to one year unaltering the syllabus in the three basic subjects. So students are focusing on the easy ways to clear the university exams by accepting the concise books, which is dampening the real quality of the subject knowledge. This study is aimed at understanding the best methods of physiology teaching in the lecture gallery, from the student's perspective. The present study was undertaken at a private medical college in southern part of India in Telangana state, on 100 students who took admission in first year MBBS course, in the academic year 2015-2016. Out of 100, 36 are boys and 64 are girl students. Distributed a question paper which is having 2 sets of questions. First question is having three statements regarding the teaching methods namely; chalk and blackboard teaching, over head projection teaching and power point teaching. Students were asked to choose the best statement which they prefer. Second question is consisting of combination of teaching methods and they are; chalk and blackboard with over head projection teaching method, chalk and blackboard with power point presentation. Again the students were asked to choose one of the 2 statements in 2 nd question. Students preference of teaching methods for understanding of physiology in percentage; chalk and blackboard-54, over head projection teaching-4, power point presentation-32, chalk and blackboard with over head projection-26, chalk and blackboard with power point presentation-64. Majority of the students are in favor of a combination of chalk and blackboard with power point presentation for better understanding of physiology, next is chalk and blackboard teaching alone.

The CUPID (Cultural and Psychosocial Influences on Disability study: methods of data collection and characteristics of study sample.

Directory of Open Access Journals (Sweden)

David Coggon

Full Text Available The CUPID (Cultural and Psychosocial Influences on Disability study was established to explore the hypothesis that common musculoskeletal disorders (MSDs and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group. As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as "repetitive strain injury" (RSI.The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs between occupational groups should allow the study hypothesis to be addressed effectively.

The CUPID (Cultural and Psychosocial Influences on Disability) Study: Methods of Data Collection and Characteristics of Study Sample

Science.gov (United States)

Coggon, David; Ntani, Georgia; Palmer, Keith T.; Felli, Vanda E.; Harari, Raul; Barrero, Lope H.; Felknor, Sarah A.; Gimeno, David; Cattrell, Anna; Serra, Consol; Bonzini, Matteo; Solidaki, Eleni; Merisalu, Eda; Habib, Rima R.; Sadeghian, Farideh; Kadir, Masood; Warnakulasuriya, Sudath S. P.; Matsudaira, Ko; Nyantumbu, Busisiwe; Sim, Malcolm R.; Harcombe, Helen; Cox, Ken; Marziale, Maria H.; Sarquis, Leila M.; Harari, Florencia; Freire, Rocio; Harari, Natalia; Monroy, Magda V.; Quintana, Leonardo A.; Rojas, Marianela; Salazar Vega, Eduardo J.; Harris, E. Clare; Vargas-Prada, Sergio; Martinez, J. Miguel; Delclos, George; Benavides, Fernando G.; Carugno, Michele; Ferrario, Marco M.; Pesatori, Angela C.; Chatzi, Leda; Bitsios, Panos; Kogevinas, Manolis; Oha, Kristel; Sirk, Tuuli; Sadeghian, Ali; Peiris-John, Roshini J.; Sathiakumar, Nalini; Wickremasinghe, A. Rajitha; Yoshimura, Noriko; Kielkowski, Danuta; Kelsall, Helen L.; Hoe, Victor C. W.; Urquhart, Donna M.; Derett, Sarah; McBride, David; Gray, Andrew

2012-01-01

Background The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample. Methods/Principal Findings A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI). Conclusions/Significance The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively. PMID:22792189

The Influences of Employment Status and Daily Stressors on Physiological Functioning in a Sample of Midlife and Older Adults.

Science.gov (United States)

Wong, Jen D; Shobo, Yetunde

2016-06-01

This study examines the influences of employment status and the moderating role of daily stressors on cortisol levels and responsivity in 182 workers and 253 retirees between 55 and 75 years old from the National Survey of Midlife Development in the United States (MIDUS-II). As a part of the Daily Diary Study, participants completed telephone interviews about their daily experiences across eight evenings and provided saliva samples across 4 days. Multilevel models showed that workers who experienced greater number of non-work related daily stressors significantly exhibited higher cortisol level at 30 min post awakening (b = 0.252, SE = 0.109, p stressors. Findings demonstrate the important consideration of daily stressors in identifying the ways in which social roles influence physiological functioning in midlife and late adulthood. © The Author(s) 2016.

Statistical representative elementary volumes of porous media determined using greyscale analysis of 3D tomograms

Science.gov (United States)

Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

2017-09-01

Digital rock physics carries the dogmatic concept of having to segment volume images for quantitative analysis but segmentation rejects huge amounts of signal information. Information that is essential for the analysis of difficult and marginally resolved samples, such as materials with very small features, is lost during segmentation. In X-ray nanotomography reconstructions of Hod chalk we observed partial volume voxels with an abundance that limits segmentation based analysis. Therefore, we investigated the suitability of greyscale analysis for establishing statistical representative elementary volumes (sREV) for the important petrophysical parameters of this type of chalk, namely porosity, specific surface area and diffusive tortuosity, by using volume images without segmenting the datasets. Instead, grey level intensities were transformed to a voxel level porosity estimate using a Gaussian mixture model. A simple model assumption was made that allowed formulating a two point correlation function for surface area estimates using Bayes' theory. The same assumption enables random walk simulations in the presence of severe partial volume effects. The established sREVs illustrate that in compacted chalk, these simulations cannot be performed in binary representations without increasing the resolution of the imaging system to a point where the spatial restrictions of the represented sample volume render the precision of the measurement unacceptable. We illustrate this by analyzing the origins of variance in the quantitative analysis of volume images, i.e. resolution dependence and intersample and intrasample variance. Although we cannot make any claims on the accuracy of the approach, eliminating the segmentation step from the analysis enables comparative studies with higher precision and repeatability.

The influence of sampling unit size and spatial arrangement patterns on neighborhood-based spatial structure analyses of forest stands

Energy Technology Data Exchange (ETDEWEB)

Wang, H.; Zhang, G.; Hui, G.; Li, Y.; Hu, Y.; Zhao, Z.

2016-07-01

Aim of study: Neighborhood-based stand spatial structure parameters can quantify and characterize forest spatial structure effectively. How these neighborhood-based structure parameters are influenced by the selection of different numbers of nearest-neighbor trees is unclear, and there is some disagreement in the literature regarding the appropriate number of nearest-neighbor trees to sample around reference trees. Understanding how to efficiently characterize forest structure is critical for forest management. Area of study: Multi-species uneven-aged forests of Northern China. Material and methods: We simulated stands with different spatial structural characteristics and systematically compared their structure parameters when two to eight neighboring trees were selected. Main results: Results showed that values of uniform angle index calculated in the same stand were different with different sizes of structure unit. When tree species and sizes were completely randomly interspersed, different numbers of neighbors had little influence on mingling and dominance indices. Changes of mingling or dominance indices caused by different numbers of neighbors occurred when the tree species or size classes were not randomly interspersed and their changing characteristics can be detected according to the spatial arrangement patterns of tree species and sizes. Research highlights: The number of neighboring trees selected for analyzing stand spatial structure parameters should be fixed. We proposed that the four-tree structure unit is the best compromise between sampling accuracy and costs for practical forest management. (Author)

Analysis of Product Sampling for New Product Diffusion Incorporating Multiple-Unit Ownership

Directory of Open Access Journals (Sweden)

Zhineng Hu

2014-01-01

Full Text Available Multiple-unit ownership of nondurable products is an important component of sales in many product categories. Based on the Bass model, this paper develops a new model considering the multiple-unit adoptions as a diffusion process under the influence of product sampling. Though the analysis aims to determine the optimal dynamic sampling effort for a firm and the results demonstrate that experience sampling can accelerate the diffusion process, the best time to send free samples is just before the product being launched. Multiple-unit purchasing behavior can increase sales to make more profit for a firm, and it needs more samples to make the product known much better. The local sensitivity analysis shows that the increase of both external coefficients and internal coefficients has a negative influence on the sampling level, but the internal influence on the subsequent multiple-unit adoptions has little significant influence on the sampling. Using the logistic regression along with linear regression, the global sensitivity analysis gives a whole analysis of the interaction of all factors, which manifests the external influence and multiunit purchase rate are two most important factors to influence the sampling level and net present value of the new product, and presents a two-stage method to determine the sampling level.

Determination of the influence of dispersion pattern of pesticide-resistant individuals on the reliability of resistance estimates using different sampling plans.

Science.gov (United States)

Shah, R; Worner, S P; Chapman, R B

2012-10-01

Pesticide resistance monitoring includes resistance detection and subsequent documentation/ measurement. Resistance detection would require at least one (≥1) resistant individual(s) to be present in a sample to initiate management strategies. Resistance documentation, on the other hand, would attempt to get an estimate of the entire population (≥90%) of the resistant individuals. A computer simulation model was used to compare the efficiency of simple random and systematic sampling plans to detect resistant individuals and to document their frequencies when the resistant individuals were randomly or patchily distributed. A patchy dispersion pattern of resistant individuals influenced the sampling efficiency of systematic sampling plans while the efficiency of random sampling was independent of such patchiness. When resistant individuals were randomly distributed, sample sizes required to detect at least one resistant individual (resistance detection) with a probability of 0.95 were 300 (1%) and 50 (10% and 20%); whereas, when resistant individuals were patchily distributed, using systematic sampling, sample sizes required for such detection were 6000 (1%), 600 (10%) and 300 (20%). Sample sizes of 900 and 400 would be required to detect ≥90% of resistant individuals (resistance documentation) with a probability of 0.95 when resistant individuals were randomly dispersed and present at a frequency of 10% and 20%, respectively; whereas, when resistant individuals were patchily distributed, using systematic sampling, a sample size of 3000 and 1500, respectively, was necessary. Small sample sizes either underestimated or overestimated the resistance frequency. A simple random sampling plan is, therefore, recommended for insecticide resistance detection and subsequent documentation.

Behaviour of Water Droplets Under the Influence of a Uniform Electric Field in Nanocomposite Samples of Epoxy Resin/TiO2

Directory of Open Access Journals (Sweden)

Α. Bairaktari

2013-10-01

Full Text Available In this paper nanocomposite samples of epoxy resin and TiO2 nanoparticles were investigated with water droplets on their surface. A uniform electric field was applied and the behaviour of the water droplets was observed. Parameters that were studied were the water conductivity, the droplet volume, the number of droplets and the droplet positioning with respect to (w.r.t. the electrodes. All above mentioned parameters influence the flashover voltage of the samples. It is to be noted that – at least in some cases – the water droplet positioning w.r.t. the electrodes was more important in determining the flashover voltage than the droplet volume.

Influences of religion and culture on continuing bonds in a sample of British Muslims of Pakistani origin.

Science.gov (United States)

Hussein, Hanan; Oyebode, Jan R

2009-11-01

This study considered the nature of continuing bonds with deceased relatives in a sample of Pakistani Muslims living in the United Kingdom. Ten participants were interviewed following a cultural psychology approach and transcripts were analyzed using grounded theory methodology. Dreaming, talking with others about the deceased, following the deceased's example, keeping memories and mementos, and doing actions thought to help the deceased were forms of continued relationship found. These were intertwined with the process of grieving and were influenced by the family, culture, and religion. Religion was a strong influence on the prominence given by participants to finishing well and on the notion of doing actions thought to help the deceased. Cultural mores, such as the community, and collectivist ethos and the expectation that emotion would be expressed around the time of death, were found to be supportive for some but sources of tension for other participants. Expressing a continuing bond through following the deceased's example so as to make them proud or happy seemed to be reinforced by cultural roots in respect for elders. Participants gave instances of tensions in areas such as expression of emotion and communality versus individualism that arose as a result of their position between two cultural frameworks, some illustrating how assimilation into the host culture set up conflict with the expected norms of their family/ancestral culture. The study highlights how understanding different cultural and religious influences may enrich the concept of continuing bonds.

The influence of technological parameters on the dynamic behavior of "liquid wood" samples obtained by injection molding

Science.gov (United States)

Plavanescu Mazurchevici, Simona; Carausu, Constantin; Comaneci, Radu; Nedelcu, Dumitru

2017-10-01

The plastic products contribute to environmental pollution. Replacing the plastic materials with biodegradable materials with superior properties is an absolute necessity and important research direction for the near future. The first steps in this regard were the creation of composite materials containing natural fibers with positive effects on the environment that have penetrated in different fields. The bioplastics and biocomposites made from natural fibers is a topical solution. The next step was made towards obtaining biodegradable and recyclable materials based on cellulose, lignin and no carcinogens. In this category fall the "liquid wood" with a use up to five times without affecting the mechanical properties. "Liquid wood" is a high quality thermoplastic biocomposite. "Liquid wood" is a biopolymer composite divided in three categories, ARBOFORM®, ARBOBLEND® and ARBOFILL®, which have differed composition in terms of lignin percentage, being delivered by Tecnaro, as granules, [1]. The paper's research was focus on Arboform L V3 Nature and Arboform L V3 Nature reinforced with aramid fiber. In the experimental plan were taken into account six parameters (Dinj - direction of injection [°]; Ttop - melting temperature [°C]; Pinj - injection pressure [MPa] Ss - speed [m/min]; tinj - injection time [s] and tc - cooling time [s]) each with two levels, research carried on by Taguchi methodology. Processing Taguchi method allowed both Taguchi setting work parameters influence on storage modulus and damping as the size and influence their ranking. Experimental research concerning the influence technological parameters on storage modulus of samples obtained by injection from Arboform L V3 Nature yielded an average of 6055MPa and descending order as follows: Trac, Ss, Pinj, Dinj and Ttop. The average of model for reinforced material was 6419MPa and descending order of parameters influence such as: Dinj, Trac, Ttop, tinj, Ss and Pinj.

Influence of Ongoing Task Difficulty and Motivation Level on Children's Prospective Memory in a Chinese Sample.

Science.gov (United States)

Han, Pi-Guo; Han, Lei; Bian, Yu-Long; Tian, Yu; Xu, Min-Xia; Gao, Feng-Qiang

2017-01-01

Prospective memory (PM) is the process associated with the task of realizing delayed intentions in the future. Researchers distinguish two types of PM, namely time-based PM (tbPM) and event-based PM (ebPM). Experiment 1 investigated the developmental trajectory of 3- to 5-year-old preschool children's PM ability, and the occurrence of delayed retrieval (children execute the PM task in a larger window of opportunity) in both tbPM and ebPM tasks. Results revealed that the 5-year-old children outperformed the 3- and 4-year-old children in PM. Moreover, delayed retrieval was more likely to occur in tbPM task than in ebPM task. In Experiment 2, the influence of ongoing task (OT) difficulty on PM performance was investigated with a sample of 5-year-old children. Results revealed no significant effect of OT difficulty on PM performance. In Experiment 3, we improved children's motivation level to complete the OT, then explored the influence of OT difficulty on children's PM performance. Results revealed that the effect of OT difficulty on PM performance became significant after increasing the children's motivation to complete the OT. These results provide insights into the mechanism of attentional resource allocation in PM tasks and have crucial educational and social implications.

[Considering housing arrangements in elderly life: factors influencing plans concerning future housing arrangements and preferences in a representative sample of 45+ year olds].

Science.gov (United States)

Spangenberg, L; Glaesmer, H; Brähler, E; Kersting, A; Strauß, B

2013-04-01

Providing care and support for the elderly is a future challenge. Using regression analysis, a representative population-based sample (n = 1,445) was examined with respect to whether they had considered future housing and which variables influenced their thoughts and preferences. The majority of the sample reported thinking about housing in old age and preferred to stay at home in old age. Thoughts about future housing and housing preferences were predicted by different factors in the age groups analyzed. Thinking about future housing was positively associated with increasing age and depression. Other relevant predictors were gender, living with a partner, images of old age (especially negative ones), and anticipated subjective health. These variables also predicted housing preferences. Thoughts about future living arrangements are widespread, and their importance increases with age. The wishes reported do contrast to a certain extent with reality. Planning future care as well as developing consultation guidelines should address these issues while considering the reported influences.

Quantifying Preferential Flow and Seasonal Storage in an Unsaturated Fracture-Facial Domain

Science.gov (United States)

Nimmo, J. R.; Malek-Mohammadi, S.

2012-12-01

Preferential flow through deep unsaturated zones of fractured rock is hydrologically important to a variety of contaminant transport and water-resource issues. The unsaturated zone of the English Chalk Aquifer provides an important opportunity for a case study of unsaturated preferential flow in isolation from other flow modes. The chalk matrix has low hydraulic conductivity and stays saturated, owing to its fine uniform pores and the wet climate of the region. Therefore the substantial fluxes observed in the unsaturated chalk must be within fractures and interact minimally with matrix material. Price et al. [2000] showed that irregularities on fracture surfaces provide a significant storage capacity in the chalk unsaturated zone, likely accounting for volumes of water required to explain unexpected dry-season water-table stability during substantial continuing streamflow observed by Lewis et al. [1993] In this presentation we discuss and quantify the dynamics of replenishment and drainage of this unsaturated zone fracture-face storage domain using a modification of the source-responsive model of Nimmo [2010]. This model explains the processes in terms of two interacting flow regimes: a film or rivulet preferential flow regime on rough fracture faces, active on an individual-storm timescale, and a regime of adsorptive and surface-tension influences, resembling traditional diffuse formulations of unsaturated flow, effective mainly on a seasonal timescale. The modified model identifies hydraulic parameters for an unsaturated fracture-facial domain lining the fractures. Besides helping to quantify the unsaturated zone storage described by Price et al., these results highlight the importance of research on the topic of unsaturated-flow relations within a near-fracture-surface domain. This model can also facilitate understanding of mechanisms for reinitiation of preferential flow after temporary cessation, which is important in multi-year preferential flow through deep

Andet husgeråd

DEFF Research Database (Denmark)

Dobat, A.S.; Roesdahl, Else; Pedersen, Anne

2014-01-01

Group of finds from Aggersborg: chalk vessels, querns, spit, handles, spoon?, strike-a-lights, knives......Group of finds from Aggersborg: chalk vessels, querns, spit, handles, spoon?, strike-a-lights, knives...

Social Network Status and Depression among Adolescents: An Examination of Social Network Influences and Depressive Symptoms in a Chinese Sample

OpenAIRE

Okamoto, Janet; Johnson, C. Anderson; Leventhal, Adam; Milam, Joel; Pentz, Mary Ann; Schwartz, David; Valente, Thomas W.

2011-01-01

Despite the well established influence of peer experiences on adolescent attitudes, thoughts, and behaviors, surprisingly little research has examined the importance of peer context and the increased prevalence of depressive symptoms accompanying the transition into adolescence. Examination of social networks may provide some insight into the role of peers in the vulnerability of some adolescents to depression. To address this issue, we leveraged an existing sample of 5,563 Chinese 10th grade...

Iron influence in self-attenuation of gamma radiation in sand samples

Energy Technology Data Exchange (ETDEWEB)

Aquino, Reginaldo R.; Cavalcante, Fernanda; Pecequilo, Brigitte R.S, E-mail: raquino@ipen.br, E-mail: fcavalcante@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

2013-07-01

Self-attenuation of gamma rays are usually observed in sand samples, due to the presence of iron particles of natural or anthropogenic causes, which may lead to misleading activities concentrations results. As iron atoms are often present in sand samples, the self-attenuation contribution from this mineral requires special attention when assessing sand samples radioactivity. This contributions in verified in the in the present study, using several silica (sand-like) samples doped with different concentrations of iron. The samples were arranged with pure SiO{sub 4} (98,9%) mineral from the region of Setiba, (Espirito Santo state, Brazil) and Itabirito mineral, from Itabira (Minas Gerais state, Brazil), using standard 100 mL high density polyethylene (HDPE) flat-botton cylindrical flasks, each sealed using a 52.5 mm plan screw cap and bubble spigot. Three samples were arranged in different concentrations - Fe 25% and SiO{sub 4} 75%; Fe 50% and SiO{sub 4} 50%; Fe 75% and SiO{sub 4} 25% and two other samples were assembled in the same geometry, using 100% SiO{sub 4} and 100% Fe. These samples were exposed to a large spectrum of gamma radiation (121 keV to 1408 keV) emitted by sources of {sup 60}Co, {sup 137}Cs and {sup 152}Eu. These gamma radiations were collimated and directed over the doped samples in a high resolution gamma ray spectrometer, whose spectra were analyzed with the Winner Gamma software. The matrix effect intensity is inferred by the percentage differences observed in varying the iron concentration that proved to be more intense for lower energy radiation. (author)

To Study the Influence of Different Substrate on Shiitake Mushroom Fruiting (the First Production Report in IRAN

Directory of Open Access Journals (Sweden)

L Razeghi yadak

2011-01-01

Full Text Available Abstarct Shiitake mushroom [Lentinula edodes(Berk Singer/Pegler] has the second production class among the most important edible mushrooms. For a long time this mushroom has draw attention due to its unique flavor and taste and also therapeutic properties. ِDue to the importance of this mushroom in the world and also the effect of substrate on the production of this medicinal mushroom, a research were conducted in randomized complete block design with 6 replications on 4 different substrate formulations including: 1 sawdust, wheat bran, millet; 2 sawdust, wheat bran, molasses, chalk, calcium super phosphate; 3sawdust, wheat bran, tea waste; 4sawdust, saccharose, citric acid, chalk and calcium carbonate on L.edodes production for determining the suitable substarte on early fruiting, yield, biological effeciency, average mushroom numbers and weights per block. Results showed that substrate formulation 1 caused earlier fruiting than others (58 days from incubation time, this formulation also had the highest yield (112/3 g/log and biological effeciency (35/09% between the others formula. mashroom number was the most in substrate formulation 1 (16/67 n/log and the highest mushroom wieght was obtained from formulation 4 (14/33 g/per mushroom. there wasn’t any significant differences at (p≤0.05 between substrate formulation 1 and 2. Keywords: Shiitake, Substrate formulation, Yield, Biological effeciency, Mushroom number and weight

The influence of active coping and perceived stress on health disparities in a multi-ethnic low income sample

Directory of Open Access Journals (Sweden)

Tomar Scott L

2008-01-01

Full Text Available Abstract Background Extensive research has shown that ethnic health disparities are prevalent and many psychological and social factors influence health disparities. Understanding what factors influence health disparities and how to eliminate health disparities has become a major research objective. The purpose of this study was to examine the impact of coping style, stress, socioeconomic status (SES, and discrimination on health disparities in a large urban multi-ethnic sample. Methods Data from 894 participants were collected via telephone interviews. Independent variables included: coping style, SES, sex, perceived stress, and perceived discrimination. Dependent variables included self-rated general and oral health status. Data analysis included multiple linear regression modeling. Results Coping style was related to oral health for Blacks (B = .23, p Conclusion Our results indicate that perceived stress is a critical component in understanding health outcomes for all ethnoracial groups. While SES related significantly to general health for Whites and Hispanics, this relationship was mediated by perceived stress. Active coping was associated only with oral health.

The influence of pyrolysis and matrix modifiers on determination of Cr and Pb in sediment samples by GFAAS

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Risfidian Mohadi

2016-04-01

Full Text Available Abstract: The Influence of pyrolysis and matrix modifiers on determination of Cr and Pb in sediment samples using graphite furnace atomic absorption spectrometry has been investigated. The sediment samples including three certified reference materials (CRMs are reported. Analyses were performed using microwave assisted dissolution. The matrix modifiers Mg(NO32, Pd+Mg(NO32 and NH4H2PO4were shown to be optimazed. The recovery for Cr and Pb in CRMs in the case of sample dissolution was found to be between 81 to 91% for Cr and 94 to 98% for Pb of the certified values, respectively. Keywords: Sediment, Pyrolysis, Matrix modifiers, Cr, Pb Abstrak (Indonesia: Pengaruh pirolisis dan matriks pengubah pada penentuan Cr dan Pb dalam sampel sedimen menggunakan tungku grafit spektroskopi serapan atom telah diteliti. Sampel sedimen termasuk tiga bahan referensi bersertifikat (CRMs dilaporkan dianalisis dengan menggunakan bantuan microwave ekstraktor. Matriks pengubah Mg(NO32, Pd+Mg(NO32 dan NH4H2PO4 telah digunakan dan menghasilkan nilai temu balik untuk Cr dan Pb dalam CRMs ditemukan antara 81-91% untuk Cr dan 94-98 % untuk Pb dari nilai sertifikat masing-masing. Katakunci: Sedimen, Pirolisis, Matrix modifiers, Cr, Pb

Quantitative analysis of nano-pore geomaterials and representative sampling for digital rock physics

Science.gov (United States)

Yoon, H.; Dewers, T. A.

2014-12-01

Geomaterials containing nano-pores (e.g., shales and carbonate rocks) have become increasingly important for emerging problems such as unconventional gas and oil resources, enhanced oil recovery, and geologic storage of CO2. Accurate prediction of coupled geophysical and chemical processes at the pore scale requires realistic representation of pore structure and topology. This is especially true for chalk materials, where pore networks are small and complex, and require characterization at sub-micron scale. In this work, we apply laser scanning confocal microscopy to characterize pore structures and microlithofacies at micron- and greater scales and dual focused ion beam-scanning electron microscopy (FIB-SEM) for 3D imaging of nanometer-to-micron scale microcracks and pore distributions. With imaging techniques advanced for nano-pore characterization, a problem of scale with FIB-SEM images is how to take nanometer scale information and apply it to the thin-section or larger scale. In this work, several texture characterization techniques including graph-based spectral segmentation, support vector machine, and principal component analysis are applied for segmentation clusters represented by 1-2 FIB-SEM samples per each cluster. Geometric and topological properties are analyzed and lattice-Boltzmann method (LBM) is used to obtain permeability at several different scales. Upscaling of permeability to the Darcy scale (e.g., the thin-section scale) with image dataset will be discussed with emphasis on understanding microfracture-matrix interaction, representative volume for FIB-SEM sampling, and multiphase flow and reactive transport. Funding from the DOE Basic Energy Sciences Geosciences Program is gratefully acknowledged. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under

Influence of pH, Temperature and Sample Size on Natural and Enforced Syneresis of Precipitated Silica

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Sebastian Wilhelm

2015-12-01

Full Text Available The production of silica is performed by mixing an inorganic, silicate-based precursor and an acid. Monomeric silicic acid forms and polymerizes to amorphous silica particles. Both further polymerization and agglomeration of the particles lead to a gel network. Since polymerization continues after gelation, the gel network consolidates. This rather slow process is known as “natural syneresis” and strongly influences the product properties (e.g., agglomerate size, porosity or internal surface. “Enforced syneresis” is the superposition of natural syneresis with a mechanical, external force. Enforced syneresis may be used either for analytical or preparative purposes. Hereby, two open key aspects are of particular interest. On the one hand, the question arises whether natural and enforced syneresis are analogous processes with respect to their dependence on the process parameters: pH, temperature and sample size. On the other hand, a method is desirable that allows for correlating natural and enforced syneresis behavior. We can show that the pH-, temperature- and sample size-dependency of natural and enforced syneresis are indeed analogous. It is possible to predict natural syneresis using a correlative model. We found that our model predicts maximum volume shrinkages between 19% and 30% in comparison to measured values of 20% for natural syneresis.

Lagoa Real design. Influence study of sampling support on reserve evaluation from AN-13 (Cachoeira mine), Lagoa Real, Bahia, Brazil

International Nuclear Information System (INIS)

Bastian, E.B.; Nogueira, R.A.C.

1984-09-01

This work analysis the effects followed by the change of sampling support from Cachoeira Mine. The differencies observed on U3 O8 tonnage oscillate between - 0,62 to + 0,01 %, while that the ore tonnage per reserve category change + 0,87% to + 1,59%, with the U3O8 ratio changing -1,52% to + 1,87%. This results mean the short influence carried by the support change in reserves, when the problem is analysed by the global aspect. (author)

[Influence of an observer in the haemolysis produced during the extraction of blood samples in primary care].

Science.gov (United States)

Bel-Peña, N; Mérida-de la Torre, F J

2015-01-01

To check whether an intervention based on direct observation and complementary information to nurses helps reduce haemolysis when drawing blood specimens. Random sampling study in primary care centres in the serrania de Málaga health management area, using a cross-sectional, longitudinal pre- and post-intervention design. The study period was from August 2012 to January 2015. The level of free haemoglobin was measured by direct spectrophotometry in the specimens extracted. It was then checked whether the intervention influenced the level of haemolysis, and if this was maintained over time. The mean haemolysis measured pre-intervention was 17%, and after intervention it was 6.1%. A year later and under the same conditions, the frequency of haemolysis was measured again the samples analysed, and the percentage was 9% These results are low when compared to the level obtained pre-intervention, but are higher when compared to the levels obtained immediately after the intervention. The transport and analysis conditions were the same. An intervention based on a direct and informative observation in the process of collecting blood samples contributes significantly to reduce the level of haemolysis. This effect is maintained in time. This intervention needs to be repeated to maintain its effectiveness. Audits and continuing education programs are useful for quality assurance procedures, and maintain the level of care needed for a good quality of care. Copyright © 2015 SECA. Published by Elsevier Espana. All rights reserved.

An Examination of Workplace Influences on Active Commuting in a Sample of University Employees.

Science.gov (United States)

Bopp, Melissa; Sims, Dangaia; Colgan, Joanna; Rovniak, Liza; Matthews, Stephen A; Poole, Erika

2016-01-01

Active commuting (AC; walking or biking) to work is associated with many benefits, though rates remain low. Employers can benefit from greater employee AC, through improved employee physical activity, though how the workplace is related to AC is unclear. The current study sought to examine how the workplace environment is related to AC participation. This was a cross-sectional, online survey conducted in April-May 2014. A volunteer sample of university employees (n = 551) was recruited. A large university in the northeastern United States. The online survey addressed travel habits, demographics, and workplace social and physical environment for AC. Pearson correlations and t tests were used to examine relationships between the percentage of all trips as AC and workplace influences and a multivariate regression analysis predicted AC participation. Participants reported 0.86 ± 2.6 AC trips per week. Percentage of trips as AC trips associated with perceived coworker AC (P < .001), parking availability (r = -0.22, P < .001), and bike parking availability (r = 0.24, P < .001). Individuals reporting greater walking time from their parking spot to their workplace reported a higher percentage of trips as AC compared with those with closer parking (P < .001). Individuals with a parking pass were less likely to AC than those with no permit (P < .001). The full multivariate model explained 42.5% of the variance in percentage of trips per week via AC (P < .001), having a parking pass (B = 0.23, P < .001), parking availability (B = -0.17, P < .001), perceived coworkers AC (B = 0.08, P = .02), and greater perceived walk time to campus (B = -0.43, P < .001) as significant predictors. This study provided insight into institutional influences on AC, indicating that policy, infrastructure, and programmatic initiatives could be used to promote workplace AC.

Substance abuse treatment response in a Latino sample: the influence of family conflict.

Science.gov (United States)

Fish, Jessica N; Maier, Candice A; Priest, Jacob B

2015-02-01

Latino Americans report underutilization of treatment and poor treatment response for substance use and abuse compared to other racial/ethnic groups; thus, it is important to assess factors that contribute to these disparities. The current study objective was to assess the influence of family conflict on substance abuse treatment response in a sample of Latino Americans using two different yet complementary analyses. First, ordinary least squares regression was used to assess the association between overall family conflict and pre- and post-treatment substance use. Second, repeated measures latent class analysis was used to identify groups based on family member conflict and timing of conflict during treatment. Findings indicated that family conflict contributed unique variance to concurrent substance use; however pre-treatment family conflict was not related to post-treatment outcomes. Results also identified three distinct family conflict groups: no/low conflict, pre-treatment conflict, and post-treatment conflict who differed in pre- and post-treatment substance use. Post hoc investigation revealed that those who experienced pre-treatment conflict but low post-treatment conflict showed the greatest decrease in substance use. Findings highlight the importance of considering family conflict during all stages of treatment for Latino American substance users. Copyright © 2015 Elsevier Inc. All rights reserved.

Failure Probability Estimation Using Asymptotic Sampling and Its Dependence upon the Selected Sampling Scheme

Directory of Open Access Journals (Sweden)

Martinásková Magdalena

2017-12-01

Full Text Available The article examines the use of Asymptotic Sampling (AS for the estimation of failure probability. The AS algorithm requires samples of multidimensional Gaussian random vectors, which may be obtained by many alternative means that influence the performance of the AS method. Several reliability problems (test functions have been selected in order to test AS with various sampling schemes: (i Monte Carlo designs; (ii LHS designs optimized using the Periodic Audze-Eglājs (PAE criterion; (iii designs prepared using Sobol’ sequences. All results are compared with the exact failure probability value.

Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

Directory of Open Access Journals (Sweden)

P. Stollsteiner

2015-04-01

Full Text Available This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

Science.gov (United States)

Stollsteiner, P.; Bessiere, H.; Nicolas, J.; Allier, D.; Berthet, O.

2015-04-01

This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

An accident involving transport of radioactive materials, Canada 1994 March

Energy Technology Data Exchange (ETDEWEB)

Keeling, F; Dunn, L E.G. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

1996-12-31

AECL-Chalk River Laboratories (CRL) located at Chalk River, Ontario, routinely ships radioisotopes in bulk to Nordion International Inc. in Kanata, Ontario. On 1994 March 22, an AECL vehicle carrying three packages containing radioisotopes collided with a tractor trailer carrying steel, approximately 15 km east of the Chalk River Laboratories. The AECL-CRL emergency response plan was activated. A series of post-accident meetings were held to evaluate the effectiveness of the plan and to address any identified deficiencies. AECL-CRL is continuing to work towards addressing the identified deficiencies. (author). 2 figs.

An accident involving transport of radioactive materials, Canada 1994 March

International Nuclear Information System (INIS)

Keeling, F.; Dunn, L.E.G.

1995-01-01

AECL-Chalk River Laboratories (CRL) located at Chalk River, Ontario, routinely ships radioisotopes in bulk to Nordion International Inc. in Kanata, Ontario. On 1994 March 22, an AECL vehicle carrying three packages containing radioisotopes collided with a tractor trailer carrying steel, approximately 15 km east of the Chalk River Laboratories. The AECL-CRL emergency response plan was activated. A series of post-accident meetings were held to evaluate the effectiveness of the plan and to address any identified deficiencies. AECL-CRL is continuing to work towards addressing the identified deficiencies. (author). 2 figs

Characterizing lentic freshwater fish assemblages using multiple sampling methods

Science.gov (United States)

Fischer, Jesse R.; Quist, Michael C.

2014-01-01

Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

Influence of sample preparation on the transformation of low-density to high-density amorphous ice: An explanation based on the potential energy landscape

Science.gov (United States)

Giovambattista, Nicolas; Starr, Francis W.; Poole, Peter H.

2017-07-01

Experiments and computer simulations of the transformations of amorphous ices display different behaviors depending on sample preparation methods and on the rates of change of temperature and pressure to which samples are subjected. In addition to these factors, simulation results also depend strongly on the chosen water model. Using computer simulations of the ST2 water model, we study how the sharpness of the compression-induced transition from low-density amorphous ice (LDA) to high-density amorphous ice (HDA) is influenced by the preparation of LDA. By studying LDA samples prepared using widely different procedures, we find that the sharpness of the LDA-to-HDA transformation is correlated with the depth of the initial LDA sample in the potential energy landscape (PEL), as characterized by the inherent structure energy. Our results show that the complex phenomenology of the amorphous ices reported in experiments and computer simulations can be understood and predicted in a unified way from knowledge of the PEL of the system.

Influence of Sampling Effort on the Estimated Richness of Road-Killed Vertebrate Wildlife

Science.gov (United States)

Bager, Alex; da Rosa, Clarissa A.

2011-05-01

Road-killed mammals, birds, and reptiles were collected weekly from highways in southern Brazil in 2002 and 2005. The objective was to assess variation in estimates of road-kill impacts on species richness produced by different sampling efforts, and to provide information to aid in the experimental design of future sampling. Richness observed in weekly samples was compared with sampling for different periods. In each period, the list of road-killed species was evaluated based on estimates the community structure derived from weekly samplings, and by the presence of the ten species most subject to road mortality, and also of threatened species. Weekly samples were sufficient only for reptiles and mammals, considered separately. Richness estimated from the biweekly samples was equal to that found in the weekly samples, and gave satisfactory results for sampling the most abundant and threatened species. The ten most affected species showed constant road-mortality rates, independent of sampling interval, and also maintained their dominance structure. Birds required greater sampling effort. When the composition of road-killed species varies seasonally, it is necessary to take biweekly samples for a minimum of one year. Weekly or more-frequent sampling for periods longer than two years is necessary to provide a reliable estimate of total species richness.

Failure Characteristics of Granite Influenced by Sample Height-to-Width Ratios and Intermediate Principal Stress Under True-Triaxial Unloading Conditions

Science.gov (United States)

Li, Xibing; Feng, Fan; Li, Diyuan; Du, Kun; Ranjith, P. G.; Rostami, Jamal

2018-05-01

The failure modes and peak unloading strength of a typical hard rock, Miluo granite, with particular attention to the sample height-to-width ratio (between 2 and 0.5), and the intermediate principal stress was investigated using a true-triaxial test system. The experimental results indicate that both sample height-to-width ratios and intermediate principal stress have an impact on the failure modes, peak strength and severity of rockburst in hard rock under true-triaxial unloading conditions. For longer rectangular specimens, the transition of failure mode from shear to slabbing requires higher intermediate principal stress. With the decrease in sample height-to-width ratios, slabbing failure is more likely to occur under the condition of lower intermediate principal stress. For same intermediate principal stress, the peak unloading strength monotonically increases with the decrease in sample height-to-width. However, the peak unloading strength as functions of intermediate principal stress for different types of rock samples (with sample height-to-width ratio of 2, 1 and 0.5) all present the pattern of initial increase, followed by a subsequent decrease. The curves fitted to octahedral shear stress as a function of mean effective stress also validate the applicability of the Mogi-Coulomb failure criterion for all considered rock sizes under true-triaxial unloading conditions, and the corresponding cohesion C and internal friction angle φ are calculated. The severity of strainburst of granite depends on the sample height-to-width ratios and intermediate principal stress. Therefore, different supporting strategies are recommended in deep tunneling projects and mining activities. Moreover, the comparison of test results of different σ 2/ σ 3 also reveals the little influence of minimum principal stress on failure characteristics of granite during the true-triaxial unloading process.

Mapping of groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India, using remote sensing and GIS techniques.

Science.gov (United States)

Thilagavathi, N; Subramani, T; Suresh, M; Karunanidhi, D

2015-04-01

This study proposes to introduce the remote sensing and geographic information system (GIS) techniques in mapping the groundwater potential zones. Remote sensing and GIS techniques have been used to map the groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India. Charnockites and fissile hornblende biotite gneiss are the major rock types in this region. Dunites and peridodites are the ultramafic rocks which cut across the foliation planes of the gneisses and are highly weathered. It comprises magnesite and chromite deposits which are excavated by five mining companies by adopting bench mining. The thickness of weathered and fracture zone varies from 2.2 to 50 m in gneissic formation and 5.8 to 55 m in charnockite. At the contacts of gneiss and charnockite, the thickness ranges from 9.0 to 90.8 m favoring good groundwater potential. The mine lease area is underlined by fractured and sheared hornblende biotite gneiss where groundwater potential is good. Water catchment tanks in this area of 5 km radius are small to moderate in size and are only seasonal. They remain dry during summer seasons. As perennial water resources are remote, the domestic and agricultural activities in this region depend mainly upon the groundwater resources. The mines are located in gently slope area, and accumulation of water is not observed except in mine pits even during the monsoon period. Therefore, it is essential to map the groundwater potential zones for proper management of the aquifer system. Satellite imageries were also used to extract lineaments, hydrogeomorphic landforms, drainage patterns, and land use, which are the major controlling factors for the occurrence of groundwater. Various thematic layers pertaining to groundwater existence such as geology, geomorphology, land use/land cover, lineament, lineament density, drainage, drainage density, slope, and soil were generated using GIS tools. By integrating all the above thematic layers based on the ranks and

Investigating the influence of standard staining procedures on the copper distribution and concentration in Wilson's disease liver samples by laser ablation-inductively coupled plasma-mass spectrometry.

Science.gov (United States)

Hachmöller, Oliver; Aichler, Michaela; Schwamborn, Kristina; Lutz, Lisa; Werner, Martin; Sperling, Michael; Walch, Axel; Karst, Uwe

2017-12-01

The influence of rhodanine and haematoxylin and eosin (HE) staining on the copper distribution and concentration in liver needle biopsy samples originating from patients with Wilson's disease (WD), a rare autosomal recessive inherited disorder of the copper metabolism, is investigated. In contemporary diagnostic of WD, rhodanine staining is used for histopathology, since rhodanine and copper are forming a red to orange-red complex, which can be recognized in the liver tissue using a microscope. In this paper, a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method is applied for the analysis of eight different WD liver samples. Apart from a spatially resolved elemental detection as qualitative information, this LA-ICP-MS method offers also quantitative information by external calibration with matrix-matched gelatine standards. The sample set of this work included an unstained and a rhodanine stained section of each WD liver sample. While unstained sections of WD liver samples showed very distinct structures of the copper distribution with high copper concentrations, rhodanine stained sections revealed a blurred copper distribution with significant decreased concentrations in a range from 20 to more than 90%. This implies a copper removal from the liver tissue by complexation during the rhodanine staining. In contrast to this, a further HE stained sample of one WD liver sample did not show a significant decrease in the copper concentration and influence on the copper distribution in comparison to the unstained section. Therefore, HE staining can be combined with the analysis by means of LA-ICP-MS in two successive steps from one thin section of a biopsy specimen. This allows further information to be gained on the elemental distribution by LA-ICP-MS additional to results obtained by histological staining. Copyright © 2017 Elsevier GmbH. All rights reserved.

Critical evaluation of sample pretreatment techniques.

Science.gov (United States)

Hyötyläinen, Tuulia

2009-06-01

Sample preparation before chromatographic separation is the most time-consuming and error-prone part of the analytical procedure. Therefore, selecting and optimizing an appropriate sample preparation scheme is a key factor in the final success of the analysis, and the judicious choice of an appropriate procedure greatly influences the reliability and accuracy of a given analysis. The main objective of this review is to critically evaluate the applicability, disadvantages, and advantages of various sample preparation techniques. Particular emphasis is placed on extraction techniques suitable for both liquid and solid samples.

Influence of agrochemical characteristics of 85Sr and 137Cs in soil samples from the localities around nuclear power plants in Slovak Republic

International Nuclear Information System (INIS)

Cipakova, A.; Mitro, A.

1997-01-01

Sorption of radiostrontium and radiocesium, two biologically available radionuclides in soils was studied. Experiments were carried out on the soil samples from the localities around nuclear power plants. Adsorption processes are the function of many factors. Multi-para-metrical regression analysis was used for studying of the influence of agrochemical characteristics on sorption of 85 Sr and 137 Cs in observed soil types. (authors)

Fractures and Rock Mechanics, Phase 1

DEFF Research Database (Denmark)

Krogsbøll, Anette; Jakobsen, Finn; Madsen, Lena

1997-01-01

The main objective of the project is to combine geological descriptions of fractures, chalk types and rock mechanical properties in order to investigate whether the chosen outcrops can be used as analogues to reservoir chalks. This report deals with 1) geological descriptions of outcrop locality...

Sequential effects in pigeon delayed matching-to-sample performance.

Science.gov (United States)

Roitblat, H L; Scopatz, R A

1983-04-01

Pigeons were tested in a three-alternative delayed matching-to-sample task in which second-choices were permitted following first-choice errors. Sequences of responses both within and between trials were examined in three experiments. The first experiment demonstrates that the sample information contained in first-choice errors is not sufficient to account for the observed pattern of second choices. This result implies that second-choices following first-choice errors are based on a second examination of the contents of working memory. Proactive interference was found in the second experiment in the form of a dependency, beyond that expected on the basis of trial independent response bias, of first-choices from one trial on the first-choice emitted on the previous trial. Samples from the previous trial were not found to exert a significant influence on later trials. The magnitude of the intertrial association (Experiment 3) did not depend on the duration of the intertrial interval. In contrast, longer intertrial intervals and longer sample durations did facilitate choice accuracy, by strengthening the association between current samples and choices. These results are incompatible with a trace-decay and competition model; they suggest strongly that multiple influences act simultaneously and independently to control delayed matching-to-sample responding. These multiple influences include memory for the choice occurring on the previous trial, memory for the sample, and general effects of trial spacing.

In-homogeneity in the pre-dose sensitization of the 110 °C TL peak in various quartz samples: The influence of annealing

International Nuclear Information System (INIS)

Polymeris, George S.; Oniya, Ebenezer O.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Kitis, George

2012-01-01

The pre-dose sensitization effect of the 110 °C TL glow-peak of quartz is a basic tool in thermoluminescence and optically stimulated luminescence dating and retrospective dosimetry. In the present work, a homogeneity study was performed on pre-dose sensitization in grains obtained from large quartz crystals samples collected from 10 different origins. The aliquot – to – aliquot scatter of the pre-dose sensitization of the 110 °C TL peak within each quartz crystal was monitored. The influence of the annealing on this scattering was also studied. Therefore, the investigation was applied to the un-fired “as is” samples as well as to samples annealed at 900 °C for 1 h following cooling to room temperature in air. The results showed that in the case of “as is” quartz the sensitization effect vary strongly within each aliquot of the same quartz sample. This strong variation is removed by both the high temperature annealing as well as heating up to 500 °C, involved in the TL measurements. These results are generally discussed in the framework of existing models and applications of the effect.

Guidance for air sampling at nuclear facilities

International Nuclear Information System (INIS)

Breslin, A.J.

1976-11-01

The principal uses of air sampling at nuclear facilities are to monitor general levels of radioactive air contamination, identify sources of air contamination, and evaluate the effectiveness of contaminant control equipment, determine exposures of individual workers, and provide automatic warning of hazardous concentrations of radioactivity. These applications of air sampling are discussed with respect to standards of occupational exposure, instrumentation, sample analysis, sampling protocol, and statistical treatment of concentration data. Emphasis is given to the influence of spacial and temporal variations of radionuclide concentration on the location, duration, and frequency of air sampling

Can groundwater sampling techniques used in monitoring wells influence methane concentrations and isotopes?

Science.gov (United States)

Rivard, Christine; Bordeleau, Geneviève; Lavoie, Denis; Lefebvre, René; Malet, Xavier

2018-03-06

Methane concentrations and isotopic composition in groundwater are the focus of a growing number of studies. However, concerns are often expressed regarding the integrity of samples, as methane is very volatile and may partially exsolve during sample lifting in the well and transfer to sampling containers. While issues concerning bottle-filling techniques have already been documented, this paper documents a comparison of methane concentration and isotopic composition obtained with three devices commonly used to retrieve water samples from dedicated observation wells. This work lies within the framework of a larger project carried out in the Saint-Édouard area (southern Québec, Canada), whose objective was to assess the risk to shallow groundwater quality related to potential shale gas exploitation. The selected sampling devices, which were tested on ten wells during three sampling campaigns, consist of an impeller pump, a bladder pump, and disposable sampling bags (HydraSleeve). The sampling bags were used both before and after pumping, to verify the appropriateness of a no-purge approach, compared to the low-flow approach involving pumping until stabilization of field physicochemical parameters. Results show that methane concentrations obtained with the selected sampling techniques are usually similar and that there is no systematic bias related to a specific technique. Nonetheless, concentrations can sometimes vary quite significantly (up to 3.5 times) for a given well and sampling event. Methane isotopic composition obtained with all sampling techniques is very similar, except in some cases where sampling bags were used before pumping (no-purge approach), in wells where multiple groundwater sources enter the borehole.

Influence of common preanalytical variations on the metabolic profile of serum samples in biobanks

International Nuclear Information System (INIS)

Fliniaux, Ophélie; Gaillard, Gwenaelle; Lion, Antoine; Cailleu, Dominique; Mesnard, François; Betsou, Fotini

2011-01-01

A blood pre-centrifugation delay of 24 h at room temperature influenced the proton NMR spectroscopic profiles of human serum. A blood pre-centrifugation delay of 24 h at 4°C did not influence the spectroscopic profile as compared with 4 h delays at either room temperature or 4°C. Five or ten serum freeze–thaw cycles also influenced the proton NMR spectroscopic profiles. Certain common in vitro preanalytical variations occurring in biobanks may impact the metabolic profile of human serum.

Decomposition and reduction of N2O over Limestone under FBC Conditions

DEFF Research Database (Denmark)

Johnsson, Jan Erik; Jensen, Anker; Vaaben, Rikke

1997-01-01

The addition of limestone for sulfur retention in FBC has in many cases been observed to influence the emission of N2O. The catalytic activity of N2O over calcined Stevns Chalk for decomposition of N2O in a laboratory fixed bed quartz reactor was measured. It was found that calcined Stevns Chalk...... is a very active catalyst for N2O decomposition in an inert atmosphere, and the presence of 3 vol% CO increased the rate of N2O destruction by a factor of 5 due to the catalytic reduction of N2O by CO. The activity decreased with increasing CO2 concentration, and uncalcined or recarbonated limestone had...... negligible activity. Sulfation of the calcined limestone under oxidizing conditions lowered the activity, however sulfidation under reducing conditions showed that CaS is an active catalyst for the reduction of N2O by CO. Without CO present a gas solid reaction between N2O and CaS takes place and SO2...

Squeal vibrations, glass sounds, and the stick-slip effect

International Nuclear Information System (INIS)

Patitsas, A.J.

2010-01-01

The origin of the squeal acoustic emissions when a chalk is rubbed on a blackboard or better on a ceramic plate, and those when a wet finger is rubbed on a smooth surface, such as a glass surface, is sought in the stick-slip effect between the rubbing surfaces. In the case of the squealing chalk, the stick-slip effect is anchored by shear modes of vibration in about a 0.3 mm thick chalk powder band at the rubbing interface, while in the case of the wet finger on glass, by such modes in a band comprising the finger skin. Furthermore, there are the interfacial bands at the contact areas that result in the decrease of the friction coefficient with relative velocity of slide, i.e., the condition for the stick-slip effect to occur. Such bands are basically composed of the asperities on the surface of the chalk band and of the epidermis ridges and the water layer, respectively. (author)

Use of borehole-geophysical logs and hydrologic tests to characterize crystalline rock for nuclear-waste storage, Whiteshell Nuclear Research Establishment, Manitoba, and Chalk River Nuclear Laboratory, Ontario, Canada

International Nuclear Information System (INIS)

Davison, C.C.

1982-12-01

A number of borehole methods were used in the investigation of crystalline rocks at Whiteshell Nuclear Research Establishment and Chalk River Nuclear Laboratory in Canada. The selection of a crystalline-rock mass for the storage of nuclear waste likely will require the drilling and testing of a number of deep investigative boreholes in the rock mass. Although coring of at least one hole in each new area is essential, methods for making in-situ geophysical and hydrologic measurements can substitute for widespread coring and result in significant savings in time and money. Borehole-geophysical logging techniques permit the lateral extrapolation of data from a core hole. Log response is related to rock type, alteration, and the location and character of fractures. The geophysical logs that particularly are useful for these purposes are the acoustic televiewer and acoustic waveform, neutron and gamma, resistivity, temperature, and caliper. The acoustic-televiewer log of the borehole wall can provide high resolution data on the orientation and apparent width of fractures. In situ hydraulic tests of single fractures or fracture zones isolated by packers provide quantitative information on permeability, extent, and interconnection. The computer analysis of digitized acoustic waveforms has identified a part of the waveform that has amplitude variations related to permeabilities measured in the boreholes by packer tests. 38 refs., 37 figs., 4 tabs

An improved sampling method of complex network

Science.gov (United States)

Gao, Qi; Ding, Xintong; Pan, Feng; Li, Weixing

2014-12-01

Sampling subnet is an important topic of complex network research. Sampling methods influence the structure and characteristics of subnet. Random multiple snowball with Cohen (RMSC) process sampling which combines the advantages of random sampling and snowball sampling is proposed in this paper. It has the ability to explore global information and discover the local structure at the same time. The experiments indicate that this novel sampling method could keep the similarity between sampling subnet and original network on degree distribution, connectivity rate and average shortest path. This method is applicable to the situation where the prior knowledge about degree distribution of original network is not sufficient.

Influence of common preanalytical variations on the metabolic profile of serum samples in biobanks

Energy Technology Data Exchange (ETDEWEB)

Fliniaux, Ophelie [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Gaillard, Gwenaelle [Biobanque de Picardie (France); Lion, Antoine [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Cailleu, Dominique [Batiment Serres-Transfert, rue de Mai/rue Dallery, Plateforme Analytique (France); Mesnard, Francois, E-mail: francois.mesnard@u-picardie.fr [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Betsou, Fotini [Integrated Biobank of Luxembourg (Luxembourg)

2011-12-15

A blood pre-centrifugation delay of 24 h at room temperature influenced the proton NMR spectroscopic profiles of human serum. A blood pre-centrifugation delay of 24 h at 4 Degree-Sign C did not influence the spectroscopic profile as compared with 4 h delays at either room temperature or 4 Degree-Sign C. Five or ten serum freeze-thaw cycles also influenced the proton NMR spectroscopic profiles. Certain common in vitro preanalytical variations occurring in biobanks may impact the metabolic profile of human serum.

77 FR 26438 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Approval of 2011 Consent...

Science.gov (United States)

2012-05-04

... (MDE) pertaining to the GenOn Chalk Point Generating Station (Chalk Point). These revisions approve specific provisions of a 2011 Consent Decree between MDE and GenOn to reduce particulate matter (PM... www.regulations.gov or email. The www.regulations.gov Web site is an ``anonymous access'' system...

Uranium series geochemistry in aquifers: quantification of transport mechanisms of uranium and daughter products: the chalk aquifer (Champagne, France); Desequilibres des series de l'uranium dans les aquiferes: quantification des mecanismes de transport de l'uranium et de ses descendants: cas de l'aquifere de la craie (Champagne, France)

Energy Technology Data Exchange (ETDEWEB)

Hubert, A

2005-09-15

With the increase of contaminant flux of radionuclides in surface environment (soil, river, aquifer...), there is a need to understand and model the processes that control the distribution of uranium and its daughter products during transport within aquifers. We have used U-series disequilibria as an analogue for the transport of uranium and its daughter products in aquifer to understand such mechanisms. The measurements of uranium ({sup 234}U et {sup 238}U), thorium ({sup 230}Th et {sup 232}Th), {sup 226}Ra and {sup 222}Rn isotopes in the solid and liquid phases of the chalk aquifer in Champagne (East of France) allows us to understand the processes responsible for fractionation within the uranium decay chain. Fractionations are induced by physical and chemical properties of the elements (leaching, adsorption) but also by radioactive properties (recoil effect during {alpha}-decay). For the first time a comprehensive sampling of the solid phase has been performed, allowing quantifying mechanisms responsible for the long term evolution of the aquifer. A non steady state 1D model has been developed which takes into account leaching, adsorption processes as well as radioactive filiation and {alpha}-recoil effect. Retardation coefficients have been calculated for uranium, thorium and radium. The aquifer is characterised by a double porosity, and the contribution of fracture and matrix porosity on the water/rock interaction processes has been estimated. (author)

Optimization of sampling parameters for standardized exhaled breath sampling.

Science.gov (United States)

Doran, Sophie; Romano, Andrea; Hanna, George B

2017-09-05

The lack of standardization of breath sampling is a major contributing factor to the poor repeatability of results and hence represents a barrier to the adoption of breath tests in clinical practice. On-line and bag breath sampling have advantages but do not suit multicentre clinical studies whereas storage and robust transport are essential for the conduct of wide-scale studies. Several devices have been developed to control sampling parameters and to concentrate volatile organic compounds (VOCs) onto thermal desorption (TD) tubes and subsequently transport those tubes for laboratory analysis. We conducted three experiments to investigate (i) the fraction of breath sampled (whole vs. lower expiratory exhaled breath); (ii) breath sample volume (125, 250, 500 and 1000ml) and (iii) breath sample flow rate (400, 200, 100 and 50 ml/min). The target VOCs were acetone and potential volatile biomarkers for oesophago-gastric cancer belonging to the aldehyde, fatty acids and phenol chemical classes. We also examined the collection execution time and the impact of environmental contamination. The experiments showed that the use of exhaled breath-sampling devices requires the selection of optimum sampling parameters. The increase in sample volume has improved the levels of VOCs detected. However, the influence of the fraction of exhaled breath and the flow rate depends on the target VOCs measured. The concentration of potential volatile biomarkers for oesophago-gastric cancer was not significantly different between the whole and lower airway exhaled breath. While the recovery of phenols and acetone from TD tubes was lower when breath sampling was performed at a higher flow rate, other VOCs were not affected. A dedicated 'clean air supply' overcomes the contamination from ambient air, but the breath collection device itself can be a source of contaminants. In clinical studies using VOCs to diagnose gastro-oesophageal cancer, the optimum parameters are 500mls sample volume

226Ra measurement by thermal ionisation mass spectrometry: Use of 226Ra and 14C for groundwater dating

International Nuclear Information System (INIS)

Dever, L.

1997-01-01

Recent developments in thermal ionisation mass spectrometry (TIMS) and in chemical separation Ra and Ba allow to analyse 226 Ra on smaller water samples ( 3 litres). The sampling has been realised on the Chalk aquifer of the Paris basin. The water samples have been collected in the unsaturated zone using in situ filtering devices and in the unconfined and confined parts of the aquifer in the boreholes used for public water supply. 226 Ra contents vary from 0.064±0.02 dpm/kg (n=6) in the unsaturated zone to 0.119±0.069 dpm/kg (n=7) in the unconfined aquifer and 0.319±0.057 dpm/kg (n=9) in the confined aquifer. For all the samples the 226 Ra/ 238 U activity ratios are much lower than the secular equilibrium. This points out that the two isotopes have different input function in the water during the mineralisation of the solution. The good correlation (r 2 =0.9) between the 226 Ra and Sr indicates that dissolution of Chalk is the dominant mechanism of mineralisation in 226 Ra of the solution. In the Chalk the mineralisation of the water occurs in the first metres of the unsaturated zone, during the water percolation the water rock interaction takes place through dissolution and precipitation of calcite in a non steady state. According to his distribution coefficient Sr is then a better tracer of dissolution/precipitation process than Ba. Using a geochemical model based on 226 Ra/Sr and Sr/Ca ratios an 'age' of the water could be determined. With 226 Ra half life of 1620 years we obtain 'ages' varying from 150 years to 1950 years in the unconfined aquifer. For the confined part of the aquifer where the redox condition is different it is necessary to use a geochemical model based on the U concentration in the water, the 226 Ra gives in such case ages varying from 1.8ka to 12.8ka. The radiocarbon ages obtained through usual chemical and/or isotopic models are quite similar and an isochrome between 226 Ra and 14 C ages can be calculated between 0 and 8ka

How to Deal with FFT Sampling Influences on ADEV Calculations

National Research Council Canada - National Science Library

Chang, Po-Cheng

2007-01-01

...) values while the numerical integration is used for the time and frequency (T&F) conversion. These ADEV errors occur because parts of the FFT sampling have no contributions to the ADEV calculation...

Sampling strategies for estimating brook trout effective population size

Science.gov (United States)

Andrew R. Whiteley; Jason A. Coombs; Mark Hudy; Zachary Robinson; Keith H. Nislow; Benjamin H. Letcher

2012-01-01

The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from...

Optimizing total reflection X-ray fluorescence for direct trace element quantification in proteins I: Influence of sample homogeneity and reflector type

Science.gov (United States)

Wellenreuther, G.; Fittschen, U. E. A.; Achard, M. E. S.; Faust, A.; Kreplin, X.; Meyer-Klaucke, W.

2008-12-01

Total reflection X-ray fluorescence (TXRF) is a very promising method for the direct, quick and reliable multi-elemental quantification of trace elements in protein samples. With the introduction of an internal standard consisting of two reference elements, scandium and gallium, a wide range of proteins can be analyzed, regardless of their salt content, buffer composition, additives and amino acid composition. This strategy also enables quantification of matrix effects. Two potential issues associated with drying have been considered in this study: (1) Formation of heterogeneous residues of varying thickness and/or density; and (2) separation of the internal standard and protein during drying (which has to be prevented to allow accurate quantification). These issues were investigated by microbeam X-ray fluorescence (μXRF) with special emphasis on (I) the influence of sample support and (II) the protein / buffer system used. In the first part, a model protein was studied on well established sample supports used in TXRF, PIXE and XRF (Mylar, siliconized quartz, Plexiglas and silicon). In the second part we imaged proteins of different molecular weight, oligomerization state, bound metals and solubility. A partial separation of protein and internal standard was only observed with untreated silicon, suggesting it may not be an adequate support material. Siliconized quartz proved to be the least prone to heterogeneous drying of the sample and yielded the most reliable results.

Optimizing total reflection X-ray fluorescence for direct trace element quantification in proteins I: Influence of sample homogeneity and reflector type

Energy Technology Data Exchange (ETDEWEB)

Wellenreuther, G. [European Molecular Biology Laboratory, Notkestr. 85, 22603 Hamburg (Germany); Fittschen, U.E.A. [Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Achard, M.E.S.; Faust, A.; Kreplin, X. [European Molecular Biology Laboratory, Notkestr. 85, 22603 Hamburg (Germany); Meyer-Klaucke, W. [European Molecular Biology Laboratory, Notkestr. 85, 22603 Hamburg (Germany)], E-mail: Wolfram@embl-hamburg.de

2008-12-15

Total reflection X-ray fluorescence (TXRF) is a very promising method for the direct, quick and reliable multi-elemental quantification of trace elements in protein samples. With the introduction of an internal standard consisting of two reference elements, scandium and gallium, a wide range of proteins can be analyzed, regardless of their salt content, buffer composition, additives and amino acid composition. This strategy also enables quantification of matrix effects. Two potential issues associated with drying have been considered in this study: (1) Formation of heterogeneous residues of varying thickness and/or density; and (2) separation of the internal standard and protein during drying (which has to be prevented to allow accurate quantification). These issues were investigated by microbeam X-ray fluorescence ({mu}XRF) with special emphasis on (I) the influence of sample support and (II) the protein / buffer system used. In the first part, a model protein was studied on well established sample supports used in TXRF, PIXE and XRF (Mylar, siliconized quartz, Plexiglas and silicon). In the second part we imaged proteins of different molecular weight, oligomerization state, bound metals and solubility. A partial separation of protein and internal standard was only observed with untreated silicon, suggesting it may not be an adequate support material. Siliconized quartz proved to be the least prone to heterogeneous drying of the sample and yielded the most reliable results.

The influence of sales promotion elements on consumers (jsc „rimi lietuva“ sample)

OpenAIRE

Markovskaja, Ivona

2016-01-01

The influence of sales promotion elements on consumer is analyzed in the Bachelor‘s Thesis. The thesis examines the information published by various foreign and Lithuanian authors. The main aim of this paper is to analyze different theories of sales promotion effectiveness, sales promotion relevance and factors influencing consumer‘s behavior. This paper analyses the theoretical aspects of sales promotion. It has become more popular in the beginning of the sixth decade. The definition of conc...

The influence of stress, depression, and anxiety on PSA screening rates in a nationally representative sample.

Science.gov (United States)

Kotwal, Ashwin A; Schumm, Phil; Mohile, Supriya G; Dale, William

2012-12-01

Prostate-specific antigen (PSA) testing for prostate cancer is controversial, with concerning rates of both overscreening and underscreening. The reasons for the observed rates of screening are unknown, and few studies have examined the relationship of psychological health to PSA screening rates. Understanding this relationship can help guide interventions to improve informed decision-making for screening. A nationally representative sample of men 57-85 years old without prostate cancer (N = 1169) from the National Social life, Health and Aging Project was analyzed. The independent relationship of validated psychological health scales measuring stress, anxiety, and depression to PSA testing rates was assessed using multivariable logistic regression analyses. PSA screening rates were significantly lower for men with higher perceived stress [odds ratio (OR) = 0.76, P = 0.006], but not for higher depressive symptoms (OR = 0.89, P = 0.22) when accounting for stress. Anxiety influences PSA screening through an interaction with number of doctor visits (P = 0.02). Among the men who visited the doctor once those with higher anxiety were less likely to be screened (OR = 0.65, P = 0.04). Conversely, those who visited the doctor 10+ times with higher anxiety were more likely to be screened (OR = 1.71, P = 0.04). Perceived stress significantly lowers PSA screening likelihood, and it seems to partly mediate the negative relationship of depression with screening likelihood. Anxiety affects PSA screening rates differently for men with different numbers of doctor visits. Interventions to influence PSA screening rates should recognize the role of the patients' psychological state to improve their likelihood of making informed decisions and improve screening appropriateness.

Dual-tip magnetic force microscopy with suppressed influence on magnetically soft samples

International Nuclear Information System (INIS)

Precner, Marián; Fedor, Ján; Šoltýs, Ján; Cambel, Vladimír

2015-01-01

Standard magnetic force microscopy (MFM) is considered as a powerful tool used for magnetic field imaging at nanoscale. The method consists of two passes realized by the magnetic tip. Within the first one, the topography pass, the magnetic tip directly touches the magnetic sample. Such contact perturbs the magnetization of the sample explored. To avoid the sample touching the magnetic tip, we present a new approach to magnetic field scanning by segregating the topological and magnetic scans with two different tips located on a cut cantilever. The approach minimizes the disturbance of sample magnetization, which could be a major problem in conventional MFM images of soft magnetic samples. By cutting the cantilever in half using the focused ion beam technique, we create one sensor with two different tips—one tip is magnetized, and the other one is left non-magnetized. The non-magnetized tip is used for topography and the magnetized one for the magnetic field imaging. The method developed we call dual-tip magnetic force microscopy (DT-MFM). We describe in detail the dual-tip fabrication process. In the experiments, we show that the DT-MFM method reduces significantly the perturbations of the magnetic tip as compared to the standard MFM method. The present technique can be used to investigate microscopic magnetic domain structures in a variety of magnetic samples and is relevant in a wide range of applications, e.g., data storage and biomedicine. (paper)

The Influence of Mark-Recapture Sampling Effort on Estimates of Rock Lobster Survival.

Directory of Open Access Journals (Sweden)

Ziya Kordjazi

Full Text Available Five annual capture-mark-recapture surveys on Jasus edwardsii were used to evaluate the effect of sample size and fishing effort on the precision of estimated survival probability. Datasets of different numbers of individual lobsters (ranging from 200 to 1,000 lobsters were created by random subsampling from each annual survey. This process of random subsampling was also used to create 12 datasets of different levels of effort based on three levels of the number of traps (15, 30 and 50 traps per day and four levels of the number of sampling-days (2, 4, 6 and 7 days. The most parsimonious Cormack-Jolly-Seber (CJS model for estimating survival probability shifted from a constant model towards sex-dependent models with increasing sample size and effort. A sample of 500 lobsters or 50 traps used on four consecutive sampling-days was required for obtaining precise survival estimations for males and females, separately. Reduced sampling effort of 30 traps over four sampling days was sufficient if a survival estimate for both sexes combined was sufficient for management of the fishery.

The Influence of Mark-Recapture Sampling Effort on Estimates of Rock Lobster Survival

Science.gov (United States)

Kordjazi, Ziya; Frusher, Stewart; Buxton, Colin; Gardner, Caleb; Bird, Tomas

2016-01-01

Five annual capture-mark-recapture surveys on Jasus edwardsii were used to evaluate the effect of sample size and fishing effort on the precision of estimated survival probability. Datasets of different numbers of individual lobsters (ranging from 200 to 1,000 lobsters) were created by random subsampling from each annual survey. This process of random subsampling was also used to create 12 datasets of different levels of effort based on three levels of the number of traps (15, 30 and 50 traps per day) and four levels of the number of sampling-days (2, 4, 6 and 7 days). The most parsimonious Cormack-Jolly-Seber (CJS) model for estimating survival probability shifted from a constant model towards sex-dependent models with increasing sample size and effort. A sample of 500 lobsters or 50 traps used on four consecutive sampling-days was required for obtaining precise survival estimations for males and females, separately. Reduced sampling effort of 30 traps over four sampling days was sufficient if a survival estimate for both sexes combined was sufficient for management of the fishery. PMID:26990561

Color surface-flow visualization of fin-generated shock wave boundary-layer interactions

Science.gov (United States)

Lu, F. K.; Settles, G. S.

1990-03-01

Kerosene-lampblack mixtures with addition of a ground colored chalk were used in an experiment on visualizing surface flows of swept shock boundary-layer interactions. The results show that contrasting colors intensify the visualization of different regions of the interaction surface, and help the eye in following the fine streaks to locate the upstream influence. The study confirms observations of the separation occurring at shock strength below accepted values. The superiority of the reported technique over the previous monochrome technique is demonstrated.

In-homogeneity in the pre-dose sensitization of the 110 Degree-Sign C TL peak in various quartz samples: The influence of annealing

Energy Technology Data Exchange (ETDEWEB)

Polymeris, George S., E-mail: polymers@auth.gr [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); ISIK University, Faculty of Science and Arts, Physics Department, Sile 34980, Istanbul (Turkey); Oniya, Ebenezer O. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); Physics and Electronics Department, Adekunle Ajasin University, PMB 01 Akungba Akoko (Nigeria); Jibiri, Nnamdi N. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Tsirliganis, Nestor C. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece)

2012-03-01

The pre-dose sensitization effect of the 110 Degree-Sign C TL glow-peak of quartz is a basic tool in thermoluminescence and optically stimulated luminescence dating and retrospective dosimetry. In the present work, a homogeneity study was performed on pre-dose sensitization in grains obtained from large quartz crystals samples collected from 10 different origins. The aliquot - to - aliquot scatter of the pre-dose sensitization of the 110 Degree-Sign C TL peak within each quartz crystal was monitored. The influence of the annealing on this scattering was also studied. Therefore, the investigation was applied to the un-fired 'as is' samples as well as to samples annealed at 900 Degree-Sign C for 1 h following cooling to room temperature in air. The results showed that in the case of 'as is' quartz the sensitization effect vary strongly within each aliquot of the same quartz sample. This strong variation is removed by both the high temperature annealing as well as heating up to 500 Degree-Sign C, involved in the TL measurements. These results are generally discussed in the framework of existing models and applications of the effect.

Region effects influence local tree species diversity.

Science.gov (United States)

Ricklefs, Robert E; He, Fangliang

2016-01-19

Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

Affective Beliefs Influence the Experience of Eating Meat

OpenAIRE

Anderson, Eric C.; Barrett, Lisa Feldman

2016-01-01

People believe they experience the world objectively, but research continually demonstrates that beliefs influence perception. Emerging research indicates that beliefs influence the experience of eating. In three studies, we test whether beliefs about how animals are raised can influence the experience of eating meat. Samples of meat were paired with descriptions of animals raised on factory farms or raised on humane farms. Importantly, the meat samples in both conditions were identical. Howe...

Influence of parasite density and sample storage time on the reliability of Entamoeba histolytica-specific PCR from formalin-fixed and paraffin-embedded tissues.

Science.gov (United States)

Frickmann, Hagen; Tenner-Racz, Klara; Eggert, Petra; Schwarz, Norbert G; Poppert, Sven; Tannich, Egbert; Hagen, Ralf M

2013-12-01

We report on the reliability of polymerase chain reaction (PCR) for the detection of Entamoeba histolytica from formalin-fixed, paraffin-embedded tissue in comparison with microscopy and have determined predictors that may influence PCR results. E. histolytica-specific and Entamoeba dispar-specific real-time PCR and microscopy from adjacent histologic sections were performed using a collection of formalin-fixed, paraffin-embedded tissue specimens obtained from patients with invasive amebiasis. Specimens had been collected during the previous 4 decades. Association of sample age, parasite density, and reliability of PCR was analyzed. E. histolytica PCR was positive in 20 of 34 biopsies (58.8%); 2 of these 20 were microscopically negative for amebae in neighboring tissue sections. PCR was negative in 9 samples with visible amebae in neighboring sections and in 5 samples without visible parasites in neighboring sections. PCR was negative in all specimens that were older than 3 decades. Low parasite counts and sample ages older than 20 years were predictors for false-negative PCR results. All samples were negative for E. dispar DNA. PCR is suitable for the detection of E. histolytica in formalin-fixed, paraffin-embedded tissue samples that are younger than 2 decades and that contain intermediate to high parasite numbers. Negative results in older samples were due to progressive degradation of DNA over time as indicated by control PCRs targeting the human 18S rRNA gene. Moreover, our findings support previous suggestions that only E. histolytica but not E. dispar is responsible for invasive amebiasis.

Influence of rice sample preparation and milling procedures on milling quality appraisals

Science.gov (United States)

The objective of this research was to investigate the effect of sample preparation and milling procedure on milling quality appraisals of rough rice. Samples of freshly harvested medium-grain rice (M202) with different initial moisture contents (MCs) ranging from 20.2% to 25.1% (w.b.) were used for...

Chemical and isotopic tracing of underground water in relation with leaching of mine spoils, Nord-Pas-de-Calais Coal Basin (France)

International Nuclear Information System (INIS)

Denimal, S.; Tribovillard, N.; Meilliez, F.; Barbecot, F.; Dever, L.

2001-01-01

Coal mining activity in the Nord-Pas-de-Calais region (Northern France) has generated many mine spoils. The oxidation of the pyrite content of such coal shales and their leaching can be a source of sulfate pollution for the underlying chalk aquifer, i.e. the main drinking water resource of the region. Two sites of study have been retained: one in the free water table zone and the other in the confined water table zone. Samples from both mine spoils have been analyzed with respect to their carbon and sulfur content and a superficial leaching of these elements has been evidenced. Water has been sampled in piezometers and boreholes close to the mine spoils and also along natural flux lines. The use of sulfur isotopes as markers of the different sulfate sources has confirmed the spoils source but has permitted to identify another source in the second site which is the Tertiary gypsum-bearing Ostricourt sands. This study has shown also that in the confined water table zone, part of the exported sulfates is reduced. This bacterial reduction of sulfates is due to a joint leaching of both carbon and sulfur in the mine spoils. A self-purification phenomenon occurs when the chalk aquifer is confined beneath the Cenozoic cover. (J.S.)

Chemical and isotopic tracing of underground water in relation with leaching of mine spoils, Nord-Pas-de-Calais Coal Basin (France); Tracage chimique et isotopique des eaux souterraines en relation avec les eaux de lixiviation de terrils, bassin minier du Nord-Pas-de-Calais (France)

Energy Technology Data Exchange (ETDEWEB)

Denimal, S.; Tribovillard, N.; Meilliez, F. [Lille-1 Univ., Lab. de Sedimentologie et Geodynamique, UMR 8577, 59 - Villeneuve-d' Ascq (France); Barbecot, F.; Dever, L. [Paris-11 Univ., Lab. d' Hydrologie et de Geochimie Isotopique, UMR 8616, 91 - Orsay (France)

2001-07-01

Coal mining activity in the Nord-Pas-de-Calais region (Northern France) has generated many mine spoils. The oxidation of the pyrite content of such coal shales and their leaching can be a source of sulfate pollution for the underlying chalk aquifer, i.e. the main drinking water resource of the region. Two sites of study have been retained: one in the free water table zone and the other in the confined water table zone. Samples from both mine spoils have been analyzed with respect to their carbon and sulfur content and a superficial leaching of these elements has been evidenced. Water has been sampled in piezometers and boreholes close to the mine spoils and also along natural flux lines. The use of sulfur isotopes as markers of the different sulfate sources has confirmed the spoils source but has permitted to identify another source in the second site which is the Tertiary gypsum-bearing Ostricourt sands. This study has shown also that in the confined water table zone, part of the exported sulfates is reduced. This bacterial reduction of sulfates is due to a joint leaching of both carbon and sulfur in the mine spoils. A self-purification phenomenon occurs when the chalk aquifer is confined beneath the Cenozoic cover. (J.S.)

TASCC newsletter volume 10 no. 1

International Nuclear Information System (INIS)

Thomson, L.

1996-01-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this January issue of TASCC is an update of the facility, letters of support to the government for research to continue at Chalk River Laboratories, home page on the Internet, collaboration on Vsystem with the Hahn-Meitner Institute and a listing of January's experiments. 1 fig

Quantitative analysis from limited sampling: influence of the chemical composition of apatites on their resistance to irradiation damage

International Nuclear Information System (INIS)

Ribet, I.; Petit, J.C.; CEA Cadarache, 13 - Saint-Paul-lez-Durance

1998-01-01

Apatites are investigated as possible high performance radioactive waste matrices for specific actinides. In this paper, we have quantified the influence of the chemical composition of apatites on their fission-track annealing behaviour. We aimed to evaluate the capability of apatites to self-anneal high densities of radiation damages produced during disposal. The thermal annealing kinetics, at 280 deg. C, of induced fission tracks has been determined for six different apatite compositions. We show that the chemical composition of apatites is a critical parameter with respect to their annealing behaviour. A mathematical treatment of the data, based upon the methodology of optimum design of experiments, allowed the quantification of the role of substitution for two major elements, of the apatite structure (Ca, P), for chlorine and for the two groups of minor elements, actinides (U+Th) and lanthanides (La+Ce+Y), which are relevant in the nuclear waste disposal context. A high actinide content enhances the annealing of fission-tracks in apatites, which is a very favourable feature of these minerals as radioactive waste matrices. This work also points to a new strategy for the best use of information provided by geological samples. In particular, the mathematical methodology proposed here allows, first, to evaluate the 'quality' of the information obtained and, second, to improve it by a proper choice of additional samples to investigate. (authors)

Elaboration of an Elasto-Plastic Model for High Porosity Chalks. Application to the Compaction of Petroleum Reservoirs Elaboration d'un modèle de comportement élasto-plastique pour les craies très poreuses. Application à la compaction des réservoirs pétroliers

Directory of Open Access Journals (Sweden)

Shahrour I.

2006-11-01

Full Text Available This paper presents a study of the compaction of petroleum reservoirs applied to very porous carbonate rocks such as chalk. In production estimates made in reservoir engineering, the processing of the mechanical problem is often greatly simplified. Good modelling of how materials behave gives special consideration to the influence of mechanical deformations on fluid recovery. After an analysis of the mechanical behaviour of very porous chalks, an elastoplastic behaviour model is derived so as to reproduce the principal experimental observations. This behaviour model can then be used to perform local simulations of the mechanical behaviour of a reservoir under- going depletion and thus to demonstrate the importance of the stress path and the initial stress state on the deformation of materials and hence on the recovery rate. Dans les applications pétrolières, les études de la compaction des roches réservoirs interviennent dans l'estimation des quantités de fluide récupérables et de la subsidence induite par la déplétion du champ de production. Dans la première partie du travail, nous montrons qu'à partir de l'équation linéarisée de la conservation de la masse de fluide, il est possible d'exprimer un taux de récupération distinguant les contributions respectives du fluide et de la roche. En ingénierie de réservoirs, l'hypothèse d'un chemin de contrainte prépondérant dans le milieu de production permet d'exprimer la contribution de la déformation de la roche au moyen de la compressibilité volumique des pores selon ce chemin. Le taux de récupération obtenu est alors dépendant du chemin de contrainte. Lorsque le chemin de contrainte dans le réservoir n'est pas homogène, il est alors nécessaire de connaître la loi de comportement mécanique du matériau étudié. Dans le cas des carbonates très poreux, nous désirons montrer l'influence liée au choix du chemin de contrainte sur les estimations obtenues par une m

Influence of Sampling Season and Sampling Protocol on Detection of Legionella Pneumophila Contamination in Hot Water / Paraugu Ņemšanas Sezonalitātes Un Paraugu Ņemšanas Metodes Ietekme Uz Legionella Pneumophila Kontaminācijas Noteikšanu Karstajš Ūdenī

Directory of Open Access Journals (Sweden)

Pūle Daina

2016-08-01

Full Text Available Legionella pneumophila is an environmental pathogen of engineered water systems that can cause different forms of legionellosis - from mild fever to potentially lethal pneumonia. Low concentrations of legionellae in natural habitats can increase markedly in engineered hot water systems where water temperatures are below 55 °C. In the current study, we aimed to investigate the influence of sampling season, hot water temperature and sampling protocol on occurrence of L. pneumophila. A total of 120 hot water samples from 20 apartment buildings were collected in two sampling periods - winter 2014 (n = 60 and summer 2015 (n = 60. Significantly higher occurrence of L. pneumophila was observed in summer 2015. Significant differences in temperature for negative and positive samples were not observed, which can be explained by low water temperatures at the point of water consumption. Temperature above 55 °C was observed only once, for all other sampling events it ranged from 14 °C to 53 °C.

Smaller calcite lattice deformation caused by occluded organic material in coccoliths than in mollusk shell

DEFF Research Database (Denmark)

Frølich, Simon; Sørensen, Henning Osholm; Hakim, Sepideh Sadat

2015-01-01

The growth and nucleation of biominerals are directed and affected by associated biological molecules. In this paper, we investigate the influence of occluded biomolecules on biogenic calcite from the coccolithophorid Pleurochrysis carterae and from chalk, a rock composed predominantly of fossil....... Two heating cycles allow us to differentiate the effects of thermal agitation and organic molecules. Single peak analysis and Rietveld refinement were combined to show significant differences resulting from the occluded biomolecules on the mineral phase in biogenic calcite in the mollusk shell...

Bottom sample taker

Energy Technology Data Exchange (ETDEWEB)

Garbarenko, O V; Slonimskiy, L D

1982-01-01

In order to improve the quality of the samples taken during offshore exploration from benthic sediments, the proposed design of the sample taker has a device which makes it possible to regulate the depth of submersion of the core lifter. For this purpose the upper part of the core lifter has an inner delimiting ring, and within the core lifter there is a piston suspended on a cable. The position of the piston in relation to the core lifter is previously assigned depending on the compactness of the benthic sediments and is fixed by tension of the cable which is held by a clamp in the cover of the core taker housing. When lowered to the bottom, the core taker is released, and under the influence of hydrostatic pressure of sea water, it enters the sediments. The magnitude of penetration is limited by the distance between the piston and the stopping ring. The piston also guarantees better preservation of the sample when the instrument is lifted to the surface.

A New Oceanic Anoxic Event 2 record from the Central North Atlantic at South East Newfoundland Ridge, IODP Expedition 342, Newfoundland Drifts

Science.gov (United States)

Junium, C. K.; Bornemann, A.; Bown, P. R.; Friedrich, O.; Moriya, K.; Kirtland Turner, S.; Whiteside, J. H.

2013-12-01

The recovery of Cretaceous, Cenomanian-Turonian black shales deposited during Oceanic Anoxic Event 2 (OAE 2) at Site U1407, South East Newfoundland Ridge (SENR), was an unexpected but fortuitous discovery that fills a gap in the pelagic Tethyan and North Atlantic geologic records. Drilling operations recovered the OAE sequence in all three holes drilled at Site U1407 defined initially on the basis of lithology and calcareous nannofossil biostratigraphy and confirmed by carbon isotope stratigraphy post-expedition. The SENR OAE 2 sequence is a classic chalk sequence punctuated by a prominent black band. Prior to OAE 2, greenish white pelagic carbonate is interrupted by thin, 2 to 5 cm thick organic-rich, gray calcareous clays. A sharp transition from greenish-white chalk to carbonate-poor sediments marks the occurrence of the organic carbon-rich black band. Within the black band are finely laminated to massive, pyritic black shales and laminated gray clays that are relatively organic carbon-lean, free of preserved benthic foraminifera and rich in radiolarians. Finely laminated greenish-gray marls overlay the black band and grade into approximately 1 meter of greenish white chalks with common 1cm chert layers and nodules. The remainder of the Turonian sequence is characterized by a notable transition to pink chalks. The thickness of the black band ranges from 15-40 cm between Holes A through C. The differences in the thickness of beds between Holes is due in part to drilling disturbances and mass wasting indicated by slump features in the overlying Turonian strata. Core scanning XRF and carbon isotopes can help resolve the nature of these differences and inform future sampling and study. Carbonate and organic carbon isotopes reveal that the δ13C excursion marking the initiation of OAE 2 is below the base of the black band. At U1407A the δ13C rise is immediately below (3 cm) the black shale, with δ13C maxima in the black band. At U1407C the initial δ13C rise is

Exposure to environmental polycyclic aromatic hydrocarbons: Influences on cellular susceptibility to DNA damage (sampling Kosice and Sofia)

Energy Technology Data Exchange (ETDEWEB)

Cebulska-Wasilewska, Antonina [Department of Radiation and Environmental Biology, Henryk Niewodniczanski Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Cracow (Poland) and Chair of the Epidemiology and Preventive Medicine, CM UJ, Cracow (Poland)]. E-mail: b7wasile@cyf-kr.edu.pl; Pawlyk, Igor [Department of Radiation and Environmental Biology, Henryk Niewodniczanski Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Cracow (Poland); Panek, Agnieszka [Department of Radiation and Environmental Biology, Henryk Niewodniczanski Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Cracow (Poland); Wiechec, Anna [Department of Radiation and Environmental Biology, Henryk Niewodniczanski Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Cracow (Poland); Kalina, Ivan [Department of Molecular Biology of the P.J.Safarik University, Kosice (Slovakia); Popov, Todor [Department of Toxicology, National Centre of Public Health Protection, Sofia (Bulgaria); Georgieva, Tzveta [Department of Toxicology, National Centre of Public Health Protection, Sofia (Bulgaria); Farmer, Peter B. [Cancer Biomarkers and Prevention Group, University of Leicester (United Kingdom)

2007-07-01

The aim of this study was to investigate a possible influence of occupational exposure to carcinogenic environmental polycyclic aromatic hydrocarbons (c-PAHs) on cellular susceptibility to the induction of the DNA damage. Monitoring was performed and blood samples were collected from two groups of male subjects: occupationally exposed and matched controls. The group exposed to c-PAHs (average age of 35.1 years) consisted of 52 policemen from Kosice and 26 policemen and 25 bus drivers (51 altogether) from Sofia. The control group (average age of 36.4 years) consisted of 54 unexposed subjects from Kosice and 24 from Sofia. In the investigated groups 52.5% of exposed subjects and 45.3% of control were current smokers. A challenging dose of X-rays (3 Gy) and an alkaline version of the single cell gel electrophoresis (SCGE) assay, known as Comet assay, were used to evaluate levels of induced DNA damage and repair kinetics in isolated human blood lymphocytes. DNA damage detected in lymphocytes prior to or after irradiation did not differ significantly between exposed and unexposed subjects. A significant decrease in repair efficiency due to exposure to PAHs was observed in the exposed individuals from Kosice and Sofia, when analysed separately or together. A negative influence of tobacco smoking on the efficiency of DNA repair was observed. Statistically significant differences were found between subgroups stratified according to education level in Sofia: the half times for DNA repair declined with the increasing level of education. These results confirm that environmental exposure to c-PAHs can alter the ability of blood lymphocytes to repair DNA damage and, as a result could potentially lead to effects that are hazardous to human health.

Factors Influencing Acceptance Of Contraceptive Methods

Directory of Open Access Journals (Sweden)

Anita Gupta

1997-04-01

Full Text Available Research Problem: What are the factors influencing acceptance of contraceptive methods. Objective: To study the determinants influencing contra­ceptive acceptance. Study design: Population based cross - sectional study. Setting: Rural area of East Delhi. Participants: Married women in the reproductive age group. Sample:Stratified sampling technique was used to draw the sample. Sample Size: 328 married women of reproductive age group. Study Variables: Socio-economic status, Type of contraceptive, Family size, Male child. Outcome Variables: Acceptance of contraceptives Statistical Analysis: By proportions. Result: Prevalence of use of contraception at the time of data collection was 40.5%. Tubectomy and vasectomy were most commonly used methods. (59.4%, n - 133. Educational status of the women positively influenced the contraceptive acceptance but income did not. Desire for more children was single most important deterrent for accepting contraception. Recommendations: (i             Traditional method of contraception should be given more attention. (ii            Couplesshould be brought in the contraceptive use net at the early stage of marriage.

Influence of external and internal conditions of detector sample treatment on the particle registration sensitivity of Solid State Nuclear Track Detectors of type CR-39

International Nuclear Information System (INIS)

Hermsdorf, Dietrich

2012-01-01

The sensitivity of charged particle registration with SSNTD is the most important parameter to decide about the applicability of those detectors in research, technology and environmental dosimetry. The sensitivity is strongly influenced by the treatment of detector samples before, during and after the exposure and the final evaluation process by chemical etching. Whereas changes in detection properties by external environmental influences are generally considered, the dependences on the etching conditions are ignored. Commonly the sensitivity is assumed to compensate variations in the etching conditions for track revealing. In the present work the validity of this hypothesis will be checked. In the frame of the existing database the sensitivity is not really independent on variations in etching temperatures and should be corrected for differences in the activation energies for stimulation of the bulk and track etching process. Differences in the concentration dependence may be of minor importance. Furthermore, the registration sensitivity depends on environmental conditions before, during and after the irradiation with particles under investigation. Such external parameters are the air pressure, the sample temperature and modification of bulk material by out-gassing in vacuum and exposure to γ-rays. However, the available database is insufficient and inaccurate to draw final conclusions on the detection properties of SSNTD under various external and internal conditions.

Factors Influencing Substance Abuse among Undergraduate ...

African Journals Online (AJOL)

The study investigated the factors influencing substance abuse amongundergraduate students in Osun State; Nigeria. A sample of 1, 200undergraduate students were randomly selected from three tertiaryinstitution in Osun State. Factors Influencing Substance Abuse Questionnaire (FISA) was developed by the researcher ...

Progress report, Physics Division, July 1 to September 30, 1976

International Nuclear Information System (INIS)

1976-10-01

Progress in the Physics Division, Chalk River Nuclear Laboratories, is reported for the period July 1 to September 30, 1976. Operation of the MP Tandem accelerator is described. Design highlights are provided for a proposed superconcucting cyclotron. Elastic and inelastic scattering experiments, many conducted in cooperation with other laboratories, are summarized. Activities of the Chalk River computation centre are also described. (O.T.)

Nuclear pursuits: The scientific biography of Wilfrid Bennett Lewis

International Nuclear Information System (INIS)

Fawcett, R.

1994-01-01

The scientific life of Wilfrid Bennett Lewis. The biography covers Lewis's role in the development of radar, his tenure as the Chief Superintendent of the Telecommunications Research Establishment at Malvern through his heading of the then fledgling Canadian nuclear research facility in Chalk River, Ontario. Lewis's drive, intelligence, and remarkable organizational skills placed him at the forefront of Canada's nuclear program. His influence lead to a collaboration between Atomic Energy of Canada Limited and Ontario Hydro that ultimately resulted in the development of the CANDU reactor. His influence was also profound in the near by town of Deep River with one prime legacy being the W.B. Lewis Library. Lewis's bibliography is included in the biography

[Does the sampling locality influence on the antifungal activity of the flavonoids of Marrubium vulgare against Aspergillus niger and Candida albicans?].

Science.gov (United States)

Bouterfas, K; Mehdadi, Z; Aouad, L; Elaoufi, M M; Khaled, M B; Latreche, A; Benchiha, W

2016-09-01

The study was undertaken to determine the effect of the sampling locality on the antifungal activity of the flavonoids extracted from the leaves of Marrubium vulgare L. against two fungal strains; Aspergillus niger ATCC 16404 and Candida albicans ATCC 10231. The leaves were collected from three different sampling localities belonging northwest Algeria: Tessala mount, M'sila forest and Ain Skhouna. The flavonoid extraction was carried out by using organic solvents with increasing polarity. A phytochemical screening was performed by staining test tubes. The inhibition diameters were measured by solid medium diffusion method. The minimum inhibitory concentrations were determined by dilution method on solid medium. The antifungal activity varied significantly (Pflavonoid extract and its concentration, and the strain fungal type. The inhibition diameters varied between 8.16 and recorded 37.5mm even recording a total inhibition of fungal growth and often exceed those induced marketed antifungals (Amphotericin, Fluconazole, Terbinafine and econazole nitrate). The minimum inhibitory concentrations (MICs) obtained range between 6.25 and 100μg/mL; experiencing strong antifungal inhibition. The phytochemical screening revealed the existence of certain flavonoids classes such as flavans and flavanols which may be responsible of this remarkable antifungal power. The sampling locality of Marrubium vulgare leaves influenced on the antifungal activity of flavonoids. These have proven very good fungistatic and worth valuing in pharmacology. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

The Behavior of Corrosion Products in Sampling Systems under Boiling Water Reactor Conditions

Energy Technology Data Exchange (ETDEWEB)

Hermansson, Hans-Peter

1977-08-15

A high pressure loop has been used to simulate sampling systems employed under BWR conditions. The reliability of the sampling method was studied in a series of six test runs. A variety of parameters that are thought to influence the reliability of the sampling was investigated. These included piping geometry, water oxygen content, flow, temperature and temperature gradients. Amongst other things the results indicate that the loss by deposition of iron containing corrosion products does not exceed 50 %; this figure is only influenced to a minor extent by the above mentioned parameters. The major part of the corrosion products thus deposited is found along the first few meters of the piping and cooler coil. A moderate prolongation of a pipe which is already relatively long should thus be incapable of producing a major influence on the sampling error

The influence of tube voltage and phantom size in computed tomography on the dose-response relationship of dicentrics in human blood samples

International Nuclear Information System (INIS)

Jost, G; Pietsch, H; Lengsfeld, P; Voth, M; Schmid, E

2010-01-01

The aim of this study was to investigate the dose response relationship of dicentrics in human lymphocytes after CT scans at tube voltages of 80 and 140 kV. Blood samples from a healthy donor placed in tissue equivalent abdomen phantoms of standard, pediatric and adipose sizes were exposed at dose levels up to 0.1 Gy using a 64-slice CT scanner. It was found that both the tube voltage and the phantom size significantly influenced the CT scan-induced linear dose-response relationship of dicentrics in human lymphocytes. Using the same phantom (standard abdomen), 80 kV CT x-rays were biologically more effective than 140 kV CT x-rays. However, it could also be determined that the applied phantom size had much more influence on the biological effectiveness. Obviously, the increasing slopes of the CT scan-induced dose response relationships of dicentrics in human lymphocytes obtained in a pediatric, a standard and an adipose abdomen have been induced by scattering effects of photons, which strongly increase with increasing phantom size.

The influence of tube voltage and phantom size in computed tomography on the dose-response relationship of dicentrics in human blood samples

Energy Technology Data Exchange (ETDEWEB)

Jost, G; Pietsch, H [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Lengsfeld, P; Voth, M [Global Medical Affairs Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Schmid, E, E-mail: Ernst.Schmid@lrz.uni-muenchen.d [Institute for Cell Biology, Center for Integrated Protein Science, University of Munich (Germany)

2010-06-07

The aim of this study was to investigate the dose response relationship of dicentrics in human lymphocytes after CT scans at tube voltages of 80 and 140 kV. Blood samples from a healthy donor placed in tissue equivalent abdomen phantoms of standard, pediatric and adipose sizes were exposed at dose levels up to 0.1 Gy using a 64-slice CT scanner. It was found that both the tube voltage and the phantom size significantly influenced the CT scan-induced linear dose-response relationship of dicentrics in human lymphocytes. Using the same phantom (standard abdomen), 80 kV CT x-rays were biologically more effective than 140 kV CT x-rays. However, it could also be determined that the applied phantom size had much more influence on the biological effectiveness. Obviously, the increasing slopes of the CT scan-induced dose response relationships of dicentrics in human lymphocytes obtained in a pediatric, a standard and an adipose abdomen have been induced by scattering effects of photons, which strongly increase with increasing phantom size.

Short communication: Influence of the sampling device on somatic cell count variation in cow milk samples (by official recording)

International Nuclear Information System (INIS)

Fouz, R.; Vilar, M.J.; Yus, E.; Sanjuán, M.L.; Diéguez, F.J.

2016-01-01

The objective of this study was to investigate the variability in cow´s milk somatic cell counts (SCC) depending on the type of milk meter used by dairy farms for official milk recording. The study was performed in 2011 and 2012 in the major cattle area of Spain. In total, 137,846 lactations of Holstein-Friesian cows were analysed at 1,912 farms. A generalised least squares regression model was used for data analysis. The model showed that the milk meter had a substantial effect on the SCC for individual milk samples obtained for official milk recording. The results suggested an overestimation of the SCC in milk samples from farms that had electronic devices in comparison with farms that used portable devices and underestimation when volumetric meters are used. A weak positive correlation was observed between the SCC and the percentage of fat in individual milk samples. The results underline the importance of considering this variable when using SCC data from milk recording in the dairy herd improvement program or in quality milk programs. (Author)

Short communication: Influence of the sampling device on somatic cell count variation in cow milk samples (by official recording)

Energy Technology Data Exchange (ETDEWEB)

Fouz, R.; Vilar, M.J.; Yus, E.; Sanjuán, M.L.; Diéguez, F.J.

2016-11-01

The objective of this study was to investigate the variability in cow´s milk somatic cell counts (SCC) depending on the type of milk meter used by dairy farms for official milk recording. The study was performed in 2011 and 2012 in the major cattle area of Spain. In total, 137,846 lactations of Holstein-Friesian cows were analysed at 1,912 farms. A generalised least squares regression model was used for data analysis. The model showed that the milk meter had a substantial effect on the SCC for individual milk samples obtained for official milk recording. The results suggested an overestimation of the SCC in milk samples from farms that had electronic devices in comparison with farms that used portable devices and underestimation when volumetric meters are used. A weak positive correlation was observed between the SCC and the percentage of fat in individual milk samples. The results underline the importance of considering this variable when using SCC data from milk recording in the dairy herd improvement program or in quality milk programs. (Author)

Influence of Self-emissions on a Mobile Laboratory and Implications for Urban Sampling

Science.gov (United States)

Wendt, L. P.

2017-12-01

The importance of urban systems as a large source of greenhouse gases has led to an increase in ground-based campaigns designed to identify and quantify sources. However, plume emissions from vehicle tailpipes can affect emissions for a stationary vehicle or if a tailwind lofts the plume over the car particularly in an urban canyons where wind flow is constrained [1]. Advances in battery technology allow for electric vehicles to sample without self-emissions. Chevrolet has released the Bolt with an estimated range of 238 miles per charge. We are designing a mobile lab using a Chevrolet Bolt with the sensors 5 ft above the ground to reduce drag. Here we investigate the occurrence of self-emissions from a gasoline mobile laboratory set-up that has been optimized to reduce self-emissions and the potential benefits of switching to an electric vehicle for urban sampling. A 2002 Toyota Sienna van and a Licor 7500 CO2/H2O analyzer were deployed to quantify self-emissions. A custom-designed rack elevated the sensors to a height of 8 feet above the tailpipe to minimize self-emission samples [1]. Emissions were sampled over 5 intervals near a relatively isolated field with the van oriented in five directions. A south-easterly wind ( 131o) provided a self-sample opportunity by orienting the car with the tailpipe between the oncoming wind and the sensors. Over 1.5 hours of measurement, 7.8 % of CO2 measurements exceeded 420 ppmv. Of these, four possible self-sample events were observed, or less than 1% with other enhancements attributed to passing cars. These were observed in mild wind conditions averaging 2.8 m/s and only with the tail pipe directly facing into the wind. Results suggest that self-sampling is small in an environment with mild sustained winds and open surroundings. Given the challenge of identifying self-emissions in an isolated environment, urban self-sampling could impact the overall sample especially as these signals may be hard to distinguish from the

The Influence of temporal sampling regime on the WFD classification of catchments within the Eden Demonstration Test Catchment Project

Science.gov (United States)

Jonczyk, Jennine; Haygarth, Phil; Quinn, Paul; Reaney, Sim

2014-05-01

A high temporal resolution data set from the Eden Demonstration Test Catchment (DTC) project is used to investigate the processes causing pollution and the influence of temporal sampling regime on the WFD classification of three catchments. This data highlights WFD standards may not be fit for purpose. The Eden DTC project is part of a UK government-funded project designed to provide robust evidence regarding how diffuse pollution can be cost-effectively controlled to improve and maintain water quality in rural river catchments. The impact of multiple water quality parameters on ecosystems and sustainable food production are being studied at the catchment scale. Three focus catchments approximately 10 km2 each, have been selected to represent the different farming practices and geophysical characteristics across the Eden catchment, Northern England. A field experimental programme has been designed to monitor the dynamics of agricultural diffuse pollution at multiple scales using state of the art sensors providing continuous real time data. The data set, which includes Total Phosphorus and Total Reactive Phosphorus, Nitrate, Ammonium, pH, Conductivity, Turbidity and Chlorophyll a reveals the frequency and duration of nutrient concentration target exceedance which arises from the prevalence of storm events of increasing magnitude. This data set is sub-sampled at different time intervals to explore how different sampling regimes affects our understanding of nutrient dynamics and the ramification of the different regimes to WFD chemical status. This presentation seeks to identify an optimum temporal resolution of data for effective catchment management and to question the usefulness of the WFD status metric for determining health of a system. Criteria based on high frequency short duration events needs to be accounted for.

Molecular phylogeny and divergence times of Malagasy tenrecs: Influence of data partitioning and taxon sampling on dating analyses

Directory of Open Access Journals (Sweden)

Glos Julian

2008-03-01

Full Text Available Abstract Background Malagasy tenrecs belong to the Afrotherian clade of placental mammals and comprise three subfamilies divided in eight genera (Tenrecinae: Tenrec, Echinops, Setifer and Hemicentetes; Oryzorictinae: Oryzorictes, Limnogale and Microgale; Geogalinae:Geogale. The diversity of their morphology and incomplete taxon sampling made it difficult until now to resolve phylogenies based on either morphology or molecular data for this group. Therefore, in order to delineate the evolutionary history of this family, phylogenetic and dating analyses were performed on a four nuclear genes dataset (ADRA2B, AR, GHR and vWF including all Malagasy tenrec genera. Moreover, the influence of both taxon sampling and data partitioning on the accuracy of the estimated ages were assessed. Results Within Afrotheria the vast majority of the nodes received a high support, including the grouping of hyrax with sea cow and the monophyly of both Afroinsectivora (Macroscelidea + Afrosoricida and Afroinsectiphillia (Tubulidentata + Afroinsectivora. Strongly supported relationships were also recovered among all tenrec genera, allowing us to firmly establish the grouping of Geogale with Oryzorictinae, and to confirm the previously hypothesized nesting of Limnogale within the genus Microgale. The timeline of Malagasy tenrec diversification does not reflect a fast adaptive radiation after the arrival on Madagascar, indicating that morphological specializations have appeared over the whole evolutionary history of the family, and not just in a short period after colonization. In our analysis, age estimates at the root of a clade became older with increased taxon sampling of that clade. Moreover an augmentation of data partitions resulted in older age estimates as well, whereas standard deviations increased when more extreme partition schemes were used. Conclusion Our results provide as yet the best resolved gene tree comprising all Malagasy tenrec genera, and may lead

Family Structure and Social Influence.

Science.gov (United States)

Olson, Dawn R.

Regardless of family form, there is a universal belief that one's family is the most powerful agent of socialization. A sample of 38 junior high school students from single parent and nuclear families completed a questionnaire in order to examine the relative effects of peer influence and family influence in single parent and nuclear families.…

Controlled chloride cracking of austenitic stainless steel tube samples

OpenAIRE

Raseroka, M.S.; Pistorius, P.C.

2009-01-01

An experimental rig has been constructed to produce chloride stress corrosion cracks in Type 304L stainless steel tube samples. The samples are to be used to test possible in situ repair methods in future work. The factor which influences the time to failure most strongly is the sample temperature; the distribution of cracks within the sample is affected by local temperature variations and by the position of the water line. Low-frequency oscillations in stress, caused by the on-off temperatur...

Chalk and computers

DEFF Research Database (Denmark)

Rasmussen, Lisa Rosén

highly connected to technological innovation that across the period has inspired hope as well as fear in teachers, pupils and parents. I take my starting point in the changing teaching aids of everyday school life to analyse how the technological development has been dealt with in the Danish school......Since 1970 school books have first been supplemented by photocopies and later PDF files and the use of Internet sites. Chalkboards have been replaced by Smart Boards and notebooks by laptops and IPADS. Digital media has made its way into the classroom and into everyday school life. This has been...... in the period 1970-2011. I wish to discuss how the analysis can benefit from a focus on the parallel introduction of thoughts concerning children’s culture, the competent child and the linkage of ‘Play & learn’. Looking at everyday life I also aim at discussing how the introduction of the new teaching aids has...

Multi-element analysis of small biological samples

International Nuclear Information System (INIS)

Rokita, E.; Cafmeyer, J.; Maenhaut, W.

1983-01-01

A method combining PIXE and INAA was developed to determine the elemental composition of small biological samples. The method needs virtually no sample preparation and less than 1 mg is sufficient for the analysis. The method was used for determining up to 18 elements in leaves taken from Cracow Herbaceous. The factors which influence the elemental composition of leaves and the possible use of leaves as an environmental pollution indicator are discussed

Power Difference in Spectrum of Sound Radiation before and after Break of Phantom by Piezoelectric Extracorporeal Shock Wave Lithotriptor

Science.gov (United States)

Kanai, Hiroshi; Jang, Yun-Seok; Chubachi, Noriyoshi; Tanahashi, Yoshikatsu

1994-05-01

This paper investigates the difference in the spectrum of sound radiated before and after the break of a phantom at a focal point of the piezoelectric extracorporeal shock wave lithotriptor (ESWL) in order to identify the break time or to examine whether a calculus exists exactly at the focal point or not. From the preliminary experiments using a piece of chalk as a phantom of a calculus to measure the sound radiated when impact is applied to the chalk by an impact hammer, it is found that the bending vibration component of the vibration is exhibited in the spectrum of sound. However, for small-sized chalk shorter than 3 cm, the peak frequency of the bending vibration is higher than 20 kHz. From the experiments using a piezoeletric ESWL, it is found that there is clear difference in the power spectra among the sound radiated before the break, that radiated just after the break in the breaking process, and that radiated when the chalk does not exist at the focal point of the ESWL. These characteristics will be effective for the examination of the existence of the calculus at the focal point.

Influence of sample geometry and microstructure on the hydrogen induced cracking characteristics under uniaxial load

Energy Technology Data Exchange (ETDEWEB)

Laureys, A., E-mail: aurelie.laureys@ugent.be [Department of Materials, Textiles and Chemical Engineering, Ghent University (UGent), Tech Lane Ghent Science Park - Campus A, Technologie park 903, B-9052 Gent (Belgium); Depover, T., E-mail: tom.depover@ugent.be [Department of Materials, Textiles and Chemical Engineering, Ghent University (UGent), Tech Lane Ghent Science Park - Campus A, Technologie park 903, B-9052 Gent (Belgium); Petrov, R., E-mail: roumen.petrov@ugent.be [Department of Materials, Textiles and Chemical Engineering, Ghent University (UGent), Tech Lane Ghent Science Park - Campus A, Technologie park 903, B-9052 Gent (Belgium); Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft (Netherlands); Verbeken, K., E-mail: kim.verbeken@ugent.be [Department of Materials, Textiles and Chemical Engineering, Ghent University (UGent), Tech Lane Ghent Science Park - Campus A, Technologie park 903, B-9052 Gent (Belgium)

2017-04-06

The present work evaluates hydrogen induced cracking in a TRIP (transformation induced plasticity) assisted steel and pure iron. The goal of this work is to understand the effect of the macroscopic stress distribution in the material on the hydrogen induced cracking phenomenon. Additionally, the effect of a complex multiphase microstructure on the characteristics of hydrogen induced cracking was investigated by comparing results for TRIP-assisted steel and pure iron as reference material. Tensile tests on notched and unnotched samples combined with in-situ electrochemical hydrogen charging were conducted. Tests were performed until the tensile strength was reached and until fracture. The resulting hydrogen induced cracks were studied by optical microscopy and scanning electron microscopy (SEM). Hydrogen induced cracks showed a typical S-shape and crack propagation was mainly transgranular, independently of the presence of a notch or the material's microstructure. This was also the case for the V-shaped secondary crack network and resulting stepped crack morphology characteristic for hydrogen induced damage. These observations indicate that the stress state surrounding the crack tip has a very large impact on the hydrogen induced cracking characteristics. The use of a notch or the presence of a different microstructure did not influence the overall hydrogen induced cracking features, but did change the kinetics of the hydrogen induced cracking process.

Influence of sample geometry and microstructure on the hydrogen induced cracking characteristics under uniaxial load

International Nuclear Information System (INIS)

Laureys, A.; Depover, T.; Petrov, R.; Verbeken, K.

2017-01-01

The present work evaluates hydrogen induced cracking in a TRIP (transformation induced plasticity) assisted steel and pure iron. The goal of this work is to understand the effect of the macroscopic stress distribution in the material on the hydrogen induced cracking phenomenon. Additionally, the effect of a complex multiphase microstructure on the characteristics of hydrogen induced cracking was investigated by comparing results for TRIP-assisted steel and pure iron as reference material. Tensile tests on notched and unnotched samples combined with in-situ electrochemical hydrogen charging were conducted. Tests were performed until the tensile strength was reached and until fracture. The resulting hydrogen induced cracks were studied by optical microscopy and scanning electron microscopy (SEM). Hydrogen induced cracks showed a typical S-shape and crack propagation was mainly transgranular, independently of the presence of a notch or the material's microstructure. This was also the case for the V-shaped secondary crack network and resulting stepped crack morphology characteristic for hydrogen induced damage. These observations indicate that the stress state surrounding the crack tip has a very large impact on the hydrogen induced cracking characteristics. The use of a notch or the presence of a different microstructure did not influence the overall hydrogen induced cracking features, but did change the kinetics of the hydrogen induced cracking process.

Sampling and Homogenization Strategies Significantly Influence the Detection of Foodborne Pathogens in Meat.

Science.gov (United States)

Rohde, Alexander; Hammerl, Jens Andre; Appel, Bernd; Dieckmann, Ralf; Al Dahouk, Sascha

2015-01-01

Efficient preparation of food samples, comprising sampling and homogenization, for microbiological testing is an essential, yet largely neglected, component of foodstuff control. Salmonella enterica spiked chicken breasts were used as a surface contamination model whereas salami and meat paste acted as models of inner-matrix contamination. A systematic comparison of different homogenization approaches, namely, stomaching, sonication, and milling by FastPrep-24 or SpeedMill, revealed that for surface contamination a broad range of sample pretreatment steps is applicable and loss of culturability due to the homogenization procedure is marginal. In contrast, for inner-matrix contamination long treatments up to 8 min are required and only FastPrep-24 as a large-volume milling device produced consistently good recovery rates. In addition, sampling of different regions of the spiked sausages showed that pathogens are not necessarily homogenously distributed throughout the entire matrix. Instead, in meat paste the core region contained considerably more pathogens compared to the rim, whereas in the salamis the distribution was more even with an increased concentration within the intermediate region of the sausages. Our results indicate that sampling and homogenization as integral parts of food microbiology and monitoring deserve more attention to further improve food safety.

Influence of sample preparation on the microstructure of tooth enamel apatite

Czech Academy of Sciences Publication Activity Database

Kallistová, Anna; Skála, Roman; Horáček, I.; Miyajima, N.; Malíková, R.

2015-01-01

Roč. 48, č. 3 (2015), s. 763-768 ISSN 0021-8898 Institutional support: RVO:67985831 Keywords : X-ray powder diffraction * sample preparation * microstructure * dental hydroxyapatite Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014

Characterization and quantification by mass spectrometry of mobile organic matter from clay rock: influence of the origin and of the sampling

International Nuclear Information System (INIS)

Huclier-Markai, S.; Landesman, C.; Montavon, G.; Grambow, B.; Monteau, F.; Fernandez, A.M.; Vinsot, A.

2012-01-01

probable low velocity, that the inventory was focused on the small organic molecules. The influence of the sampling was studied, notably by performing an experiment in which the argillite core sample was squeezed for 28 days at 175 MPa. The initial water content of the sample was 5.3% and the concentration of organic matter XX mol C/L. The structural features observed for the DOM were different from the percolated water samples either obtained in situ from the POX 1601 borehole or in lab from EST 34399 cores than for the squeezed water sample. The influence of the water collection will be discussed. Additionally, a part of organic matter can be extracted and isolated by HCl/HF treatment. This corresponds to the kerogen fraction which is insoluble in the pore water. 150 Myears solid-bound organic matter of the COx has been already investigated in several studies and originates from a mixture of marine and terrestrial sources. In addition to this, the CCl4 soluble organic fraction (bitumen) has been already characterized by liquid and gas chromatography coupled to mass spectrometry. And finally, a small fraction of the kerogen can be mobilized under alkaline conditions from the COx, a scenario which could happen at the COx/cement interface. This fraction (approx. 0,002 mol C/L) could be transported in the pore water and has been characterized to contain small molecules with carboxylic and phenolic groups. Nonetheless, in order to predict the speciation of metals and radionuclides for a given scenario, Dissolved Organic Matter (DOM) either in the pore water or that could be mobilized from the kerogen fraction must be supported by quantitative data. Thus, the present study is focused the quantification of these low molecular weight compounds using mass spectrometry. Several simple, sensitive, and reproducible methods of quantification, such as internal calibration, calibrated addition of external standard or sequential tandem mass spectrometry, have been developed and are

Serotonin transporter gene-linked polymorphic region (5-HTTLPR) influences decision making under ambiguity and risk in a large Chinese sample.

Science.gov (United States)

He, Qinghua; Xue, Gui; Chen, Chuansheng; Lu, Zhonglin; Dong, Qi; Lei, Xuemei; Ding, Ni; Li, Jin; Li, He; Chen, Chunhui; Li, Jun; Moyzis, Robert K; Bechara, Antoine

2010-11-01

Risky decision making is a complex process that involves weighing the probabilities of alternative options that can be desirable, undesirable, or neutral. Individuals vary greatly in how they make decisions either under ambiguity and/or under risk. Such individual differences may have genetic bases. Based on previous studies on the genetic basis of decision making, two decision making tasks [i.e., the Iowa Gambling Task (IGT) and Loss Aversion Task (LAT)] were used to test the effect of 5-HTTLPR polymorphism on decision making under ambiguity and under risk in a large Han Chinese sample (572 college students, 312 females). Basic intelligence and memory tests were also included to control for the influence of basic cognitive abilities on decision making. We found that 5-HTTLPR polymorphism significantly influenced performance in both IGT and LAT. After controlling for intelligence and memory abilities, subjects homozygous for s allele had lower IGT scores than l carriers in the first 40 trials of the IGT task. They also exhibited higher loss aversion than l carriers in the LAT task. Moreover, the effects of 5-HTTLPR were stronger for males than for females. These results extend the literature on the important role of emotion in decision making under ambiguity and risk, and shed additional lights on how decision making is influenced by culture as well as sex differences. Combining our results with existing literature, we propose that these effects might be mediated by a neural circuitry that comprises the amygdala, ventromedial prefrontal cortex, and insular cortex. Understanding the genetic factors affecting decision making in healthy subjects may allow us to better identify at-risk individuals, and better target the development of new potential treatments for specific disorders such as schizophrenia, addiction, and depression. Copyright © 2010 Elsevier Ltd. All rights reserved.

Serotonin Transporter Gene-Linked Polymorphic Region (5-HTTLPR) Influences Decision Making under Ambiguity and Risk in a Large Chinese Sample

Science.gov (United States)

He, Qinghua; Xue, Gui; Chen, Chuansheng; Lu, Zhonglin; Dong, Qi; Lei, Xuemei; Ding, Ni; Li, Jin; Li, He; Chen, Chunhui; Li, Jun; Moyzis, Robert K.; Bechara, Antoine

2010-01-01

Risky decision-making is a complex process that involves weighing the probabilities of alternative options that can be desirable, undesirable, or neutral. Individuals vary greatly in how they make decisions either under ambiguity and/or under risk. Such individual differences may have genetic bases. Based on previous studies on the genetic basis of decision making, two decision making tasks [i.e., Iowa Gambling Task (IGT) and Loss Aversion Task (LAT)] were used to test the effect of 5-HTTLPR polymorphism on decision making under ambiguity and under risk in a large Han Chinese sample (572 college students, 312 females). Basic intelligence and memory tests were also included to control for the influence of basic cognitive abilities on decision making. We found that 5-HTTLPR polymorphism significantly influenced performance in both IGT and LAT. After controlling for intellectual and memory abilities, subjects homozygous for s allele had lower IGT scores than l carriers in the first 40 trials of the IGT task. They also exhibited higher loss aversion than l carriers in the LAT task. Moreover, the effects of 5-HTTLPR were stronger for males than for females. These results extend the literature on the important role of emotion in decision under ambiguity and risk, and provide additional lights on how decision-making is influenced by culture as well as sex differences. Combining our results with existing literature, we propose that these effects might be mediated by a neural circuitry that comprises the amygdala, ventromedial prefrontal cortex, and insular cortex. Understanding the genetic factors affecting decision in healthy subjects may allow us better identify at-risk individuals, and target better the development of new potential treatments for specific disorders such as schizophrenia, addiction, and depression. PMID:20659488

Production of Calcareous Nannofossil Ooze for Sedimentological Experiments

DEFF Research Database (Denmark)

Buls, Toms; Anderskouv, Kresten; Fabricius, Ida Lykke

2015-01-01

by an abundance of sedimentary structures, such as drifts, moats, sediment waves, and channels documented in the Upper Cretaceous Chalk Group of NW Europe. Despite chalk being a major hydrocarbon reservoir rock of the North Sea, surprisingly little is known about the physical behavior of the pelagic carbonate......The notion of fine-grained pelagic carbonates as uniform, monotonous sequences of sediments settled in a quiescent environment has been challenged over the past few decades. Fine-grained pelagic carbonates can undergo substantial reworking after their first deposition, as illustrated...... sediment from which the chalk formed-calcareous nannofossil ooze. This poses a serious challenge to the understanding of the depositional system and the properties of facies distribution. Experimental tests, such as those performed in laboratory flumes, are necessary to provide empirical data...

Sampling artifacts in measurement of elemental and organic carbon: Low-volume sampling in indoor and outdoor environments

Science.gov (United States)

Olson, David A.; Norris, Gary A.

Experiments were completed to determine the extent of artifacts from sampling elemental carbon (EC) and organic carbon (OC) under sample conditions consistent with personal sampling. Two different types of experiments were completed; the first examined possible artifacts from oils used in personal environmental monitor (PEM) impactor plates, and the second examined artifacts from microenvironmental sampling using different sampling media combinations (quartz, Teflon, XAD denuder, and electrostatic precipitator). The effectiveness of front and backup filters was evaluated for most sampling configurations. Mean total carbon concentrations from sampling configurations using impactor oils were not statistically different from the control case (using a sharp cut cyclone). Three microenvironments were tested (kitchen, library, and ambient); carbon concentrations were highest in the kitchen using a front quartz filter (mean OC of 16.4 μg m -3). The lowest front quartz filter concentrations were measured in the library using XAD denuders (mean OC of 3.6 μg m -3). Denuder removal efficiencies (average of 82% for total carbon) were lower compared with previous ambient studies and may indicate that indoor sources influenced denuder efficiency during sample collection. The highest carbon concentrations from backup quartz filters were measured using the Teflon-quartz combination.

Influence of the mechanical sample treatment on the thermally stimulated exoelectron emission in aspect of the application for sample dating

International Nuclear Information System (INIS)

Zastawny, Andrzej; Bialon, Jan

1999-01-01

The examination was focused on a typical, contemporary produced ceramics, irradiated by the beta particles 90 Sr- 90 Y source. According to measurements, the mechanical treatment of the sample in the form of abrading and washing in alcohol did not affect the glow curve of the TSEE above the temperature 130 deg. C. Because the peaks of the TSEE, which can be taken full advantage for the dating must lie above 300 deg. C, the mechanical and washing preparing of the samples should not affect the measurements

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

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C. Romero-Trigueros

2017-10-01

Full Text Available Calibration of in situ analysers of air pollutants is usually done with dry standards. In this paper, the influence of sample temperature and environmental humidity on benzene measurements by gas chromatography coupled with a photoionisation detector (GC-PID is studied. Two reference gas mixtures (40 and 5 µg m−3 nominal concentration benzene in air were subjected to two temperature cycles (20/5/20 °C and 20/35/20 °C and measured with two identical GC-PIDs. The change in sample temperature did not produce any significant change in readings. Regarding ambient humidity, the chromatographs were calibrated for benzene with dry gases and subjected to measure reference standards with humidity (20 and 80 % at 20 °C. When measuring a concentration of 0.5 µg m−3 benzene in air, the levels of humidity tested did not produce any significant interference in measurements taken with any of the analysers. However, when measuring a concentration of 40 µg m−3, biases in measurements of 18 and 21 % for each respective analyser were obtained when the relative humidity of the sample was 80 % at 20 °C. Further tests were carried out to study the nature of this interference. Results show that humidity interference depends on both the amount fractions of water vapour and benzene. If benzene concentrations in an area are close to its annual limit value (5 µg m−3, biases of 2.2 % can be expected when the absolute humidity is 8.6 g cm−3 – corresponding to a relative humidity of 50 % at 20 °C. This can be accounted for in the uncertainty budget of measurements with no need for corrections. If benzene concentrations are above the annual limit value, biases become higher. Thus, in these cases, actions should be taken to reduce the humidity interference, as an underestimation of benzene concentrations may cause a mismanagement of air quality in these situations.

Influence of sexual stimulation on sperm parameters in semen samples collected via masturbation from normozoospermic men or cryptozoospermic men participating in an assisted reproduction programme.

Science.gov (United States)

Yamamoto, Y; Sofikitis, N; Mio, Y; Miyagawa, I

2000-05-01

To evaluate the influence of sexual stimulation via sexually stimulating videotaped visual images (VIM) on sperm function, two semen samples were collected from each of 19 normozoospermic men via masturbation with VIM. Two additional samples were collected from each man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, percentage of morphologically normal spermatozoa, outcome of hypo-osmotic swelling test and zona-free hamster oocyte sperm penetration assay, and markers of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM than masturbation without VIM. The improved sperm parameters in the samples collected via masturbation with VIM may reflect an enhanced prostatic secretory function and increased loading of the vas deferens at that time. In a similar protocol, two semen samples were collected via masturbation with VIM from each of 22 non-obstructed azoospermic men. Semen samples from these men had been occasionally positive in the past for a very small number of spermatozoa (cryptozoospermic men). Two additional samples were collected from each cryptozoospermic man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, and a marker of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM. Fourteen out of the 22 men were negative for spermatozoa in both samples collected via masturbation without VIM. These men demonstrated spermatozoa in both samples collected via masturbation with VIM. Six men with immotile spermatozoa in both samples collected via masturbation without VIM exposed motile spermatozoa in both samples collected via masturbation with VIM. High sexual stimulation during masturbation with VIM results in recovery of spermatozoa of greater fertilizing potential both in normozoospermic and cryptozoospermic men. The appearance of spermatozoa after

Simulation of range imaging-based estimation of respiratory lung motion. Influence of noise, signal dimensionality and sampling patterns.

Science.gov (United States)

Wilms, M; Werner, R; Blendowski, M; Ortmüller, J; Handels, H

2014-01-01

A major problem associated with the irradiation of thoracic and abdominal tumors is respiratory motion. In clinical practice, motion compensation approaches are frequently steered by low-dimensional breathing signals (e.g., spirometry) and patient-specific correspondence models, which are used to estimate the sought internal motion given a signal measurement. Recently, the use of multidimensional signals derived from range images of the moving skin surface has been proposed to better account for complex motion patterns. In this work, a simulation study is carried out to investigate the motion estimation accuracy of such multidimensional signals and the influence of noise, the signal dimensionality, and different sampling patterns (points, lines, regions). A diffeomorphic correspondence modeling framework is employed to relate multidimensional breathing signals derived from simulated range images to internal motion patterns represented by diffeomorphic non-linear transformations. Furthermore, an automatic approach for the selection of optimal signal combinations/patterns within this framework is presented. This simulation study focuses on lung motion estimation and is based on 28 4D CT data sets. The results show that the use of multidimensional signals instead of one-dimensional signals significantly improves the motion estimation accuracy, which is, however, highly affected by noise. Only small differences exist between different multidimensional sampling patterns (lines and regions). Automatically determined optimal combinations of points and lines do not lead to accuracy improvements compared to results obtained by using all points or lines. Our results show the potential of multidimensional breathing signals derived from range images for the model-based estimation of respiratory motion in radiation therapy.

Campylobacter in Broiler Chicken and Broiler Meat in Sri Lanka: Influence of Semi-Automated vs. Wet Market Processing on Campylobacter Contamination of Broiler Neck Skin Samples

Directory of Open Access Journals (Sweden)

Kottawattage S. A. Kottawatta

2017-11-01

Full Text Available Broiler meat can become contaminated with Campylobacter of intestinal origin during processing. The present study aimed to identify the prevalence of Campylobacter in broiler flocks and meat contamination at retail shops, and determine the influence of semi-automated and wet market processing on Campylobacter contamination of neck skin samples. Samples were collected from semi-automated plants (n = 102 and wet markets (n = 25. From each batch of broilers, pooled caecal samples and neck skin samples were tested for Campylobacter. Broiler meat purchased from retail outlets (n = 37 was also tested. The prevalence of Campylobacter colonized broiler flocks was 67%. The contamination of meat at retail was 59%. Both semi-automated and wet market processing resulted to contaminate the broiler neck skins to the levels of 27.4% and 48%, respectively. When Campylobacter-free broiler flocks were processed in semi-automated facilities 15% (5/33 of neck skin samples became contaminated by the end of processing whereas 25% (2/8 became contaminated after wet market processing. Characterization of isolates revealed a higher proportion of C. coli compared to C. jejuni. Higher proportions of isolates were resistant to important antimicrobials. This study shows the importance of Campylobacter in poultry industry in Sri Lanka and the need for controlling antimicrobial resistance.

Campylobacter in Broiler Chicken and Broiler Meat in Sri Lanka: Influence of Semi-Automated vs. Wet Market Processing on Campylobacter Contamination of Broiler Neck Skin Samples.

Science.gov (United States)

Kottawatta, Kottawattage S A; Van Bergen, Marcel A P; Abeynayake, Preeni; Wagenaar, Jaap A; Veldman, Kees T; Kalupahana, Ruwani S

2017-11-29

Broiler meat can become contaminated with Campylobacter of intestinal origin during processing. The present study aimed to identify the prevalence of Campylobacter in broiler flocks and meat contamination at retail shops, and determine the influence of semi-automated and wet market processing on Campylobacter contamination of neck skin samples. Samples were collected from semi-automated plants ( n = 102) and wet markets ( n = 25). From each batch of broilers, pooled caecal samples and neck skin samples were tested for Campylobacter . Broiler meat purchased from retail outlets ( n = 37) was also tested. The prevalence of Campylobacter colonized broiler flocks was 67%. The contamination of meat at retail was 59%. Both semi-automated and wet market processing resulted to contaminate the broiler neck skins to the levels of 27.4% and 48%, respectively. When Campylobacter -free broiler flocks were processed in semi-automated facilities 15% (5/33) of neck skin samples became contaminated by the end of processing whereas 25% (2/8) became contaminated after wet market processing. Characterization of isolates revealed a higher proportion of C. coli compared to C. jejuni . Higher proportions of isolates were resistant to important antimicrobials. This study shows the importance of Campylobacter in poultry industry in Sri Lanka and the need for controlling antimicrobial resistance.

Experiences and factors influencing a sample of teachers in New York state public elementary and middle schools to focus on environmental education in their teaching

Science.gov (United States)

Tooker, Gail Patricia

This study focuses on how fourteen elementary and middle level teachers in New York chose to teach environmental topics as part of their science curricula. Prior research suggested that factors influencing teachers to make curricular decisions are different from those that motivated them to become teachers in the first place (Espinet, et.al. 1992). This was supported by the results of this study, which found that most of these teachers made the decision to begin teaching environmental education (EE) well after deciding to become teachers and that the decision to teach EE was influenced by a variety of factors including participation in EE-oriented in-service programs, media coverage of environmental issues, encouragement from colleagues and school administrators to undertake EE, and personal experiences in childhood or early adulthood with the environment and/or with EE. Studies examining experiences that influence people to practice "environmentally responsible" behaviors (Chawla, 1995; McGarry, 1994; Tanner, 1994) suggested that positive childhood contacts with nature were important predictors for such behavior in adulthood. Findings of this study were largely consistent with these results, however, this sample of teachers viewed their childhood nature experiences as being mostly responsible for the development of their appreciation of the environment, while their actual decision to begin teaching EE was primarily influenced by other experiences, as discussed above. This study also examined how these teachers prepared themselves for teaching EE. The findings indicate that these teachers used a wide variety of preparation strategies. A minority reported becoming prepared for teaching EE through their pre-service teacher education programs. These results were in agreement with prior findings that most teacher education programs in this country do not include a focus on EE. Even where preparation for EE is included, it has been rated by the participants as

Determination of atmospheric nitrogen dioxide by sampling with impregnated filters

International Nuclear Information System (INIS)

Galiano, J.A.; Palomares, F.

1978-01-01

The performance of filters impregnated with triethanolamine for the collection and subsequent determination of atmospheric nitrogen dioxide is studied taking into account the influence of several parameters: storage of filters, reagents, elapsed time, sampling efficiency, etc. The results obtained for sampling times of 24 hours are satisfactory. (author) [es

Experience in handling concentrated tritium

International Nuclear Information System (INIS)

Holtslander, W.J.

1985-12-01

The notes describe the experience in handling concentrated tritium in the hydrogen form accumulated in the Chalk River Nuclear Laboratories Tritium Laboratory. The techniques of box operation, pumping systems, hydriding and dehydriding operations, and analysis of tritium are discussed. Information on the Chalk River Tritium Extraction Plant is included as a collection of reprints of papers presented at the Dayton Meeting on Tritium Technology, 1985 April 30 - May 2

Formulation and Implementation of a Constitutive Model for Soft Rock

OpenAIRE

Hickman, Randall John

2004-01-01

Petroleum reservoirs located in the Norwegian sector of the North Sea have undergone unexpected subsidence of great magnitude (> 10 m) during more than 30 years of petroleum recovery operations. Historical laboratory investigations have shown that the subsidence is due to the mechanical behavior and mechanical properties of chalk. Chalk behavior is characterized by elastoplasticity, including pore collapse, shear failure, and tensile failure mechanisms; rate-dependence; and pore fluid depende...

The Impact of Climate Change on Groundwater Resources and Groundwater Quality in the Patcham Catchment, England.

Science.gov (United States)

Phillips, R. J.; Smith, M.; Pope, D. J.; Gumm, L.

2012-04-01

The CLIMAWAT project is an EU-Regional Development Fund Interreg IV funded research programme to study the impacts of climate change on groundwater resources and groundwater quality from the Chalk aquifer of SE England. The use of partially treated wastewater for artificial recharge will also be extensively studied in both the field and laboratory. The Chalk is a major aquifer and regionally supplies 70% of potable water supplies. The long term sustainable use of this resource is of paramount importance and the outcomes of this project will better inform and enhance long term management strategies for this. Project partners include water companies, regulatory bodies and industry consultancies. The four main objectives of the CLIMAWAT project are: i) better improve the prediction of the impact of climate change on this groundwater resource; ii) better understand and quantify how recharge mechanisms will vary due to the uncertainty associated with climate change; iii) better understand the storage mechanisms and fate of contaminants (e.g. nitrates and pesticides) in this aquifer and iv) investigate the impact of using partially treated wastewater for artificial recharge. An extensive field monitoring and data collection programme is underway in the Patcham Catchment (SE of England). Simultaneous monitoring of climatic, unsaturated zone potentiometric, groundwater level and chemistry data will allow for a better understanding of how changes in recharge patterns will effect groundwater quality and quantity. Isoptopic analysis of sampled groundwaters has allowed for interpretations and a better understanding of the storage and movement of water through this aquifer. The laboratory experimental programme is also underway and the results from this will compliment the field based studies to further enhance the understanding of contaminant behaviour in the both unsaturated and saturated zones. Core experiments are being used to investigate how nutrient and other

Influence of sintering parameters in the ferroelectric properties os strontium bismuth tantalate samples obtained by oxide mixture

International Nuclear Information System (INIS)

Souza, R.R. de; Pereira, A.S.; Sousa, V.C.; Egea, J.R.J.

2012-01-01

The family of compounds layered-type perovskite, know as Aurivilius presents great alternative not only by the absence of lead in the composition, but because the polarization retention, replacing PZT in FeRAM devices. The strontium bismuth tantalate (SrBi 2 Ta 2 O 9 ) or SBT is ferroelectric material that has attracted considerable interest, since it has high fatigue resistance, supporting high hysteresis loops, with the change in polarization.Checking polarization and depolarization currents stimulated by temperature it is possible to obtain, for example, information about the nature of charges and about the activation energy for the process of dielectric relaxation. For analysis of ferroelectric properties of this compound, it is essential to obtain specimens with a relative density around 95%. Thus, it is important the optimization of the sintering process in order to obtain a ceramic body with a high densification. The influence of sintering parameters to obtain SrBi 2 Ta 2 O 9 in the polarization properties and in the microstructure of sintered samples was investigated by thermostimulated currents and electronic microscopy, respectively. Results show that variation of these parameters may cause changes in the ferroelectric properties of the material. (author)

Effects of innovative and conventional sanitizing treatments on the reduction of Saccharomycopsis fibuligera defects on industrial durum wheat bread.

Science.gov (United States)

Giannone, Virgilio; Pitino, Iole; Pecorino, Biagio; Todaro, Aldo; Spina, Alfio; Lauro, Maria Rosaria; Tomaselli, Filippo; Restuccia, Cristina

2016-10-17

Wickerhamomyces anomalus, Hyphopichia burtonii and Saccharomycopsis fibuligera are spoilage yeasts causing chalk mold defects on sliced bread packaged under modified atmosphere. The first objective of this study, carried out in a bread-making company for two consecutive years, was to genetically identify yeasts isolated from spoiled sliced bread in Modified Atmosphere Packaging (MAP) and to determine the dominant species among identified strains. The second objective was to evaluate the effects of hydrogen peroxide and silver solution 12% (HPS) treatment in the leavening cells and cooling chambers, in comparison with the conventional Ortho-Phenylphenol (OPP) fumigating treatment, on the incidence of chalk defects of the commercialized products. One-hundred percent of the isolated yeasts were identified as S. fibuligera, while H. burtonii and W. anomalus were not detected. Concerning mean water activity (aw) and moisture content values, packaged bread samples were, respectively, included in the range 0.922-0.940 and 33.40-35.39%. S. fibuligera was able to grow in a wide range of temperature (11.5 to 28.5°C) and relative humidity (70.00 to 80.17%) in the processing environments, and product aw<0.94. Compared to OPP, the combined treatment with hydrogen peroxide and silver solution, in association with MAP, reduced to a negligible level yeast contamination of industrial sliced bread. The identification of the spoilage organisms and a comprehensive understanding of the combined effects of aw, pO2/pCO2 inside the packages, environmental conditions and sanitizing treatment on the growth behaviour is essential for future development of adequate preventive process strategies against chalk mold defects. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of management of variables, sampling zones and land units on LR analysis for landslide spatial prevision

Directory of Open Access Journals (Sweden)

R. Greco

2013-09-01

Full Text Available Several authors, according to different methodological approaches, have employed logistic Regression (LR, a multivariate statistical analysis adopted to assess the spatial probability of landslide, even though its fundamental principles have remained unaltered. This study aims at assessing the influence of some of these methodological approaches on the performance of LR, through a series of sensitivity analyses developed over a test area of about 300 km2 in Calabria (southern Italy. In particular, four types of sampling (1 – the whole study area; 2 – transects running parallel to the general slope direction of the study area with a total surface of about 1/3 of the whole study area; 3 – buffers surrounding the phenomena with a 1/1 ratio between the stable and the unstable area; 4 – buffers surrounding the phenomena with a 1/2 ratio between the stable and the unstable area, two variable coding modes (1 – grouped variables; 2 – binary variables, and two types of elementary land (1 – cells units; 2 – slope units units have been tested. The obtained results must be considered as statistically relevant in all cases (Aroc values > 70%, thus confirming the soundness of the LR analysis which maintains high predictive capacities notwithstanding the features of input data. As for the area under investigation, the best performing methodological choices are the following: (i transects produced the best results (0 P(y ≤ 93.4%; Aroc = 79.5%; (ii as for sampling modalities, binary variables (0 P(y ≤ 98.3%; Aroc = 80.7% provide better performance than ordinated variables; (iii as for the choice of elementary land units, slope units (0 P(y ≤ 100%; Aroc = 84.2% have obtained better results than cells matrix.

Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

Directory of Open Access Journals (Sweden)

Martin M Gossner

Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

Modeling the Influence of Early Skin-to-Skin Contact on Exclusive Breastfeeding in a Sample of Hispanic Immigrant Women.

Science.gov (United States)

Linares, Ana M; Wambach, Karen; Rayens, Mary K; Wiggins, Amanda; Coleman, Elizabeth; Dignan, Mark B

2017-10-01

Using data from a longitudinal study of breastfeeding in Hispanics, this study evaluated the influence of early skin-to-skin contact (SSC) on initiation and sustained exclusive breastfeeding (EBF) at 1 month postpartum. Two-thirds of the women in the sample participated in early SSC. At discharge, over half of the women were EBF; this proportion decreased to one-third at 1 month postpartum. Controlling for demographic and clinical variables in the model, participation in early SSC was associated with a greater than sevenfold increase in the odds of EBF at discharge (p = .005) but was not predictive of EBF at 1 month post-discharge (p = .7). Younger maternal age and increased prenatal infant feeding intention were associated with an increased likelihood of EBF across both timepoints. Promoting early SSC may help with initiation of EBF, while further breastfeeding support may be needed to maintain EBF following discharge for this vulnerable population.

Temporal variation of pharmaceuticals in an urban and agriculturally influenced stream

International Nuclear Information System (INIS)

Veach, Allison M.; Bernot, Melody J.

2011-01-01

Pharmaceuticals have become ubiquitous in the aquatic environment. Previous studies consistently demonstrate the prevalence of pharmaceuticals in freshwater but we do not yet know how concentrations vary over time within a given system. Two sites in central Indiana with varying land use in the surrounding watershed (suburban and agricultural) were sampled monthly for pharmaceutical concentrations and stream physiochemical parameters. Sediment samples were also collected at each sampling event for measurement of δ 15 N natural abundance and sediment organic content. Across sites and sampling events, twelve pharmaceuticals were detected including acetaminophen, caffeine, carbamazepine, cotinine, N,N-diethyl-meta-toluamide (DEET), gemfibrozil, ibuprofen, sulfadimethoxine, sulfamethazine, sulfamethoxazole, triclosan, and trimethoprim. Sulfathiazole, lincomycin, and tylosin were not detected at either site at any time. The agriculturally-influenced site had comparable pharmaceutical concentrations to the urban-influenced site. In general, pharmaceutical concentrations increased during winter at both sites and decreased during spring and summer. Multiple regression analyses indicated that water column dissolved oxygen, the number of days since precipitation, and solar radiation influenced total pharmaceutical concentration in the urban-influenced site; whereas pH, chlorophyll a concentration, and total amount of rainfall in the previous 10 days influenced total pharmaceutical concentrations in the agriculturally-influenced site. Pharmaceutical concentrations were not correlated with sediment δ 15 N across or within sites. However, sediment in the urban-influenced site had higher mean δ 15 N signatures relative to sediment in the agriculturally-influenced site. These data indicate pharmaceuticals are persistent in aquatic ecosystems influenced by both agricultural and suburban activity. Pharmaceuticals are designed to have a physiological effect; therefore, it is

Using boreholes as windows into groundwater ecosystems.

Directory of Open Access Journals (Sweden)

James P R Sorensen

Full Text Available Groundwater ecosystems remain poorly understood yet may provide ecosystem services, make a unique contribution to biodiversity and contain useful bio-indicators of water quality. Little is known about ecosystem variability, the distribution of invertebrates within aquifers, or how representative boreholes are of aquifers. We addressed these issues using borehole imaging and single borehole dilution tests to identify three potential aquifer habitats (fractures, fissures or conduits intercepted by two Chalk boreholes at different depths beneath the surface (34 to 98 m. These habitats were characterised by sampling the invertebrates, microbiology and hydrochemistry using a packer system to isolate them. Samples were taken with progressively increasing pumped volume to assess differences between borehole and aquifer communities. The study provides a new conceptual framework to infer the origin of water, invertebrates and microbes sampled from boreholes. It demonstrates that pumping 5 m(3 at 0.4-1.8 l/sec was sufficient to entrain invertebrates from five to tens of metres into the aquifer during these packer tests. Invertebrates and bacteria were more abundant in the boreholes than in the aquifer, with associated water chemistry variations indicating that boreholes act as sites of enhanced biogeochemical cycling. There was some variability in invertebrate abundance and bacterial community structure between habitats, indicating ecological heterogeneity within the aquifer. However, invertebrates were captured in all aquifer samples, and bacterial abundance, major ion chemistry and dissolved oxygen remained similar. Therefore the study demonstrates that in the Chalk, ecosystems comprising bacteria and invertebrates extend from around the water table to 70 m below it. Hydrogeological techniques provide excellent scope for tackling outstanding questions in groundwater ecology, provided an appropriate conceptual hydrogeological understanding is applied.

LABORATORY INVESTIGATIONS OF SILICATE MUD CONTAMINATION WITH CALCIUM

Directory of Open Access Journals (Sweden)

Nediljka Gaurina-Međimurec

2004-12-01

Full Text Available The silicate-based drilling fluid is a low solids KCl/polymer system with the addition of soluble sodium or potassium silicate to enhance inhibition and wellbore stability. Silicate-based drilling fluids exhibit remarkable shale and chalk stabilizing properties, resulting in gauge hole and the formation of firm cuttings when drilling reactive shales and soft chalks. Silicates protect shales by in-situ gellation when exposed to the neutral pore fluid and precipitation, which occurs on contact with divalent ions present at the surface of the shale. Also, silicates prevent the dispersion and washouts when drilling soft chalk by reacting with the Ca2+ ions present on chalk surfaces of cutting and wellbore to form a protective film. The silicate-based drilling fluid can be used during drilling hole section through shale interbeded anhydrite formations because of its superior shale stabilizing characteristics. However, drilling through the anhydrite can decrease the silicate concentration and change rheological and filtration fluid properties. So, the critical concentration of calcium ions should be investigated by lab tests. This paper details the mechanism of shale inhibition using silicate-based drilling fluid, and presents results of lab tests conducted to ascertain the effect of Ca2+ ions on silicate level in the fluid and the fluid properties.

Influence of sample quality on phenylalanine and 17-hydroxyprogesterone levels in neonatal screening

OpenAIRE

del Río Fabre, Lesley; González, Ernesto C; Frómeta, Amarilys; Castells, Elisa M; Tejeda, Yileidis

2010-01-01

Quality of the sample and phenylalanine and 17-hydroxyprogesterone levels in neonatal screening. In the programs for neonatal screening many different analytes are quantified from dried blood on filter paper cards. Several factors affect the quality of the samples invalidating their employment in the laboratory: inadequate collection procedures, quality of the filter paper, the drying, storage and transportation under extreme environmental conditions. This article aims to show how the quality...

Sample normalization methods in quantitative metabolomics.

Science.gov (United States)

Wu, Yiman; Li, Liang

2016-01-22

To reveal metabolomic changes caused by a biological event in quantitative metabolomics, it is critical to use an analytical tool that can perform accurate and precise quantification to examine the true concentration differences of individual metabolites found in different samples. A number of steps are involved in metabolomic analysis including pre-analytical work (e.g., sample collection and storage), analytical work (e.g., sample analysis) and data analysis (e.g., feature extraction and quantification). Each one of them can influence the quantitative results significantly and thus should be performed with great care. Among them, the total sample amount or concentration of metabolites can be significantly different from one sample to another. Thus, it is critical to reduce or eliminate the effect of total sample amount variation on quantification of individual metabolites. In this review, we describe the importance of sample normalization in the analytical workflow with a focus on mass spectrometry (MS)-based platforms, discuss a number of methods recently reported in the literature and comment on their applicability in real world metabolomics applications. Sample normalization has been sometimes ignored in metabolomics, partially due to the lack of a convenient means of performing sample normalization. We show that several methods are now available and sample normalization should be performed in quantitative metabolomics where the analyzed samples have significant variations in total sample amounts. Copyright © 2015 Elsevier B.V. All rights reserved.

Three-year-olds obey the sample size principle of induction: the influence of evidence presentation and sample size disparity on young children's generalizations.

Science.gov (United States)

Lawson, Chris A

2014-07-01

Three experiments with 81 3-year-olds (M=3.62years) examined the conditions that enable young children to use the sample size principle (SSP) of induction-the inductive rule that facilitates generalizations from large rather than small samples of evidence. In Experiment 1, children exhibited the SSP when exemplars were presented sequentially but not when exemplars were presented simultaneously. Results from Experiment 3 suggest that the advantage of sequential presentation is not due to the additional time to process the available input from the two samples but instead may be linked to better memory for specific individuals in the large sample. In addition, findings from Experiments 1 and 2 suggest that adherence to the SSP is mediated by the disparity between presented samples. Overall, these results reveal that the SSP appears early in development and is guided by basic cognitive processes triggered during the acquisition of input. Copyright © 2013 Elsevier Inc. All rights reserved.

Who are health influencers? Characterizing a sample of tobacco cessation interveners.

Science.gov (United States)

Campbell, Jean; Mays, Mary Z; Yuan, Nicole P; Muramoto, Myra L

2007-01-01

To describe characteristics of health influencers (HIs) prior to training in brief tobacco cessation interventions (BI). HIs (n=910) in Arizona were recruited for a randomized controlled trial comparing training modalities. Typically middle-aged (M=43, SD=14), non-Hispanic white (68%), female (77%), non-tobacco users (93%), most identified personal (89%) rather than job-related (3%) motivators for becoming cessation interveners. Confidence about intervention ability was high (93%); knowledge scores, however, were low (M=55%, SD=13%). HIs exhibiting high motivation to intervene but lacking knowledge about BI strategies may be an untapped resource for tobacco cessation and a variety of other health promotion interventions.

The Sample Size Influence in the Accuracy of the Image Classification of the Remote Sensing

Directory of Open Access Journals (Sweden)

Thomaz C. e C. da Costa

2004-12-01

Full Text Available Landuse/landcover maps produced by classification of remote sensing images incorporate uncertainty. This uncertainty is measured by accuracy indices using reference samples. The size of the reference sample is defined by approximation by a binomial function without the use of a pilot sample. This way the accuracy are not estimated, but fixed a priori. In case of divergency between the estimated and a priori accuracy the error of the sampling will deviate from the expected error. The size using pilot sample (theorically correct procedure justify when haven´t estimate of accuracy for work area, referent the product remote sensing utility.

The influence of incubation time, sample preparation and exposure to oxygen on the quality of the MALDI-TOF MS spectrum of anaerobic bacteria.

Science.gov (United States)

Veloo, A C M; Elgersma, P E; Friedrich, A W; Nagy, E; van Winkelhoff, A J

2014-12-01

With matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), bacteria can be identified quickly and reliably. This accounts especially for anaerobic bacteria. Because growth rate and oxygen sensitivity differ among anaerobic bacteria, we aimed to study the influence of incubation time, exposure to oxygen and sample preparation on the quality of the spectrum using the Bruker system. Also, reproducibility and inter-examiner variability were determined. Twenty-six anaerobic species, representing 17 genera, were selected based on gram-stain characteristics, growth rate and colony morphology. Inter-examiner variation showed that experience in the preparation of the targets can be a significant variable. The influence of incubation time was determined between 24 and 96 h of incubation. Reliable species identification was obtained after 48 h of incubation for gram-negative anaerobes and after 72 h for gram-positive anaerobes. Exposure of the cultures to oxygen did not influence the results of the MALDI-TOF MS identifications of all tested gram-positive species. Fusobacterium necrophorum and Prevotella intermedia could not be identified after >24 h and 48 h of exposure to oxygen, respectively. Other tested gram-negative bacteria could be identified after 48 h of exposure to oxygen. Most of the tested species could be identified using the direct spotting method. Bifidobacterium longum and Finegoldia magna needed on-target extraction with 70% formic acid in order to obtain reliable species identification and Peptoniphilus ivorii a full extraction. Spectrum quality was influenced by the amount of bacteria spotted on the target, the homogeneity of the smear and the experience of the examiner. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Impact of frequent cerebrospinal fluid sampling on Aβ levels: systematic approach to elucidate influencing factors.

Science.gov (United States)

Van Broeck, Bianca; Timmers, Maarten; Ramael, Steven; Bogert, Jennifer; Shaw, Leslie M; Mercken, Marc; Slemmon, John; Van Nueten, Luc; Engelborghs, Sebastiaan; Streffer, Johannes Rolf

2016-05-19

Cerebrospinal fluid (CSF) amyloid-beta (Aβ) peptides are predictive biomarkers for Alzheimer's disease and are proposed as pharmacodynamic markers for amyloid-lowering therapies. However, frequent sampling results in fluctuating CSF Aβ levels that have a tendency to increase compared with baseline. The impact of sampling frequency, volume, catheterization procedure, and ibuprofen pretreatment on CSF Aβ levels using continuous sampling over 36 h was assessed. In this open-label biomarker study, healthy participants (n = 18; either sex, age 55-85 years) were randomized into one of three cohorts (n = 6/cohort; high-frequency sampling). In all cohorts except cohort 2 (sampling started 6 h post catheterization), sampling through lumbar catheterization started immediately post catheterization. Cohort 3 received ibuprofen (800 mg) before catheterization. Following interim data review, an additional cohort 4 (n = 6) with an optimized sampling scheme (low-frequency and lower volume) was included. CSF Aβ(1-37), Aβ(1-38), Aβ(1-40), and Aβ(1-42) levels were analyzed. Increases and fluctuations in mean CSF Aβ levels occurred in cohorts 1-3 at times of high-frequency sampling. Some outliers were observed (cohorts 2 and 3) with an extreme pronunciation of this effect. Cohort 4 demonstrated minimal fluctuation of CSF Aβ both on a group and an individual level. Intersubject variability in CSF Aβ profiles over time was observed in all cohorts. CSF Aβ level fluctuation upon catheterization primarily depends on the sampling frequency and volume, but not on the catheterization procedure or inflammatory reaction. An optimized low-frequency sampling protocol minimizes or eliminates fluctuation of CSF Aβ levels, which will improve the capability of accurately measuring the pharmacodynamic read-out for amyloid-lowering therapies. ClinicalTrials.gov NCT01436188 . Registered 15 September 2011.

Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, in-situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009

Science.gov (United States)

McCoy, Scott W.; Coe, Jeffrey A.; Kean, Jason W.; Tucker, Greg E.; Staley, Dennis M.; Wasklewicz, Thad A.

2011-01-01

Debris flows initiated by surface-water runoff during short duration, moderate- to high-intensity rainfall are common in steep, rocky, and sparsely vegetated terrain. Yet large uncertainties remain about the potential for a flow to grow through entrainment of loose debris, which make formulation of accurate mechanical models of debris-flow routing difficult. Using a combination of in situ measurements of debris flow dynamics, video imagery, tracer rocks implanted with passive integrated transponders (PIT) and pre- and post-flow 2-cm resolution digital terrain models (terrain data presented in a companion paper by STALEY et alii, 2011), we investigated the entrainment and transport response of debris flows at Chalk Cliffs, CO, USA. Four monitored events during the summer of 2009 all initiated from surface-water runoff, generally less than an hour after the first measurable rain. Despite reach-scale morphology that remained relatively constant, the four flow events displayed a range of responses, from long-runout flows that entrained significant amounts of channel sediment and dammed the main-stem river, to smaller, short-runout flows that were primarily depositional in the upper basin. Tracer-rock travel-distance distributions for these events were bimodal; particles either remained immobile or they travelled the entire length of the catchment. The long-runout, large-entrainment flow differed from the other smaller flows by the following controlling factors: peak 10-minute rain intensity; duration of significant flow in the channel; and to a lesser extent, peak surge depth and velocity. Our growing database of natural debris-flow events can be used to develop linkages between observed debris-flow transport and entrainment responses and the controlling rainstorm characteristics and flow properties.

Influence of austempering heat treatment on mechanical and corrosion properties of ductile iron samples

Directory of Open Access Journals (Sweden)

M. Janjić

2016-07-01

Full Text Available Mechanical properties and corrosion resistance of metals are closely related to the microstructure characteristics of the material. The paper compares the results of these two sets of properties after investigating samples of base ductile iron and heat-treated samples of the base austempered ductile iron (ADI. The basic material is perlite ferritic iron alloyed with copper and nickel. To test the corrosion rate of the base material (ductile iron and the heattreated samples (ADI, electrochemical techniques of potentiostatic polarization were used (the technique of Tafel curves extrapolation and the potentiodynamic polarization technique.

Magnetorheological measurements with consideration for the internal magnetic field in samples

Energy Technology Data Exchange (ETDEWEB)

Kordonski, W; Gorodkin, S [QED Technologies International, 1040 University Ave., Rochester, NY 14607 (United States)], E-mail: kordonski@qedmrf.com

2009-02-01

The magnetically induced yield stress in a sample of suspension of magnetic particles is associated with formation of a field-oriented structure, the strength of which depends on the degree of particles magnetization. This factor is largely defined by the actual magnetic field strength in the sample. At the same time it is common practice to present and analyze magnetorheological characteristics as a function of the applied magnetic field. Uncertainty of an influence function in magnetorheology hampers interpretation of data obtained with different measurement configurations. It was shown in this paper that rheological response of magnetorheological fluid to the applied magnetic field is defined by the sample's actual (internal) magnetic field intensity, which, in turn, depends on sample geometry and field orientation all other factors being equal. Utilization of the sample's actual field as an influence function in magnetorheology allows proper interpretation of data obtained with different measuring system configurations. Optimization of the actual internal field is a promising approach in designing of energy efficient magnetorheological devices.

'Neknomination': Predictors in a sample of UK university students.

Science.gov (United States)

Moss, Antony C; Spada, Marcantonio M; Harkin, Jamila; Albery, Ian P; Rycroft, Nicola; Nikčević, Ana V

2015-06-01

To identify prevalence and predictors of participation in the online drinking game 'neknomination' amongst university students. A convenience sample of 145 university students participated in a study about drinking behaviours, completing a questionnaire about their participation in neknomination, the Alcohol Use Disorders Identification Test, and the Resistance to Peer Influence Scale. Out of 145 students sampled, 54% took part in neknomination in the previous month. Mann-Whitney U tests revealed significantly higher scores on the Alcohol Use Disorders Identification Test, and significantly lower scores on the Resistance to Peer Influence Scale, for those who had participated in neknomination. A significant correlation was also shown between specific peer pressure to neknominate, and engagement in neknomination. A logistic regression analysis indicated that scores on the Alcohol Use Disorders Identification Test, but not the Resistance to Peer Influence Scale, predicted classification as an individual who participated in neknomination. We found that over half of respondents had participated in a neknomination game in the past month, with almost all male respondents having done so. Participation in neknomination was strongly associated with general hazardous drinking behaviour but not with resistance to peer influence. Further research is needed to understand the role of engagement with social media in drinking games and risky drinking.

Characterization of superconducting multilayers samples

CERN Document Server

Antoine, C Z; Berry, S; Bouat, S; Jacquot, J F; Villegier, J C; Lamura, G; Gurevich, A

2009-01-01

Best RF bulk niobium accelerating cavities have nearly reached their ultimate limits at rf equatorial magnetic field H  200 mT close to the thermodynamic critical field Hc. In 2006 Gurevich proposed to use nanoscale layers of superconducting materials with high values of Hc > HcNb for magnetic shielding of bulk niobium to increase the breakdown magnetic field inside SC RF cavities [1]. Depositing good quality layers inside a whole cavity is rather difficult but we have sputtered high quality samples by applying the technique used for the preparation of superconducting electronics circuits and characterized these samples by X-ray reflectivity, dc resistivity (PPMS) and dc magnetization (SQUID). Dc magnetization curves of a 250 nm thick Nb film have been measured, with and without a magnetron sputtered coating of a single or multiple stack of 15 nm MgO and 25 nm NbN layers. The Nb samples with/without the coating clearly exhibit different behaviors. Because SQUID measurements are influenced by edge an...

A review of sample preparation and its influence on pH determination in concrete samples; : Revisión sobre la preparación de muestras de hormigón y su influencia sobre la determinación del pH

Energy Technology Data Exchange (ETDEWEB)

Manso, S.; Aguado, A.

2017-07-01

If we are to monitor the chemical processes in cementitious materials, then pH assays in the pore solutions of cement pastes, mortars, and concretes are of key importance. However, there is no standard method that regulates the sample-preparation method for pH determination. The state-of-the-art of different methods for pH determination in cementitious materials is presented in this paper and the influence of sample preparation in each case. Moreover, an experimental campaign compares three different techniques for pH determination. Its results contribute to establishing a basic criterion to help researchers select the most suitable method, depending on the purpose of the research. A simple tool is described for selecting the easiest and the most economic pH determination method, depending on the objective; especially for researchers and those with limited experience in this field.

Temporal variation of pharmaceuticals in an urban and agriculturally influenced stream

Energy Technology Data Exchange (ETDEWEB)

Veach, Allison M., E-mail: amveach@k-state.edu; Bernot, Melody J., E-mail: mjbernot@bsu.edu

2011-10-01

Pharmaceuticals have become ubiquitous in the aquatic environment. Previous studies consistently demonstrate the prevalence of pharmaceuticals in freshwater but we do not yet know how concentrations vary over time within a given system. Two sites in central Indiana with varying land use in the surrounding watershed (suburban and agricultural) were sampled monthly for pharmaceutical concentrations and stream physiochemical parameters. Sediment samples were also collected at each sampling event for measurement of {delta}{sup 15}N natural abundance and sediment organic content. Across sites and sampling events, twelve pharmaceuticals were detected including acetaminophen, caffeine, carbamazepine, cotinine, N,N-diethyl-meta-toluamide (DEET), gemfibrozil, ibuprofen, sulfadimethoxine, sulfamethazine, sulfamethoxazole, triclosan, and trimethoprim. Sulfathiazole, lincomycin, and tylosin were not detected at either site at any time. The agriculturally-influenced site had comparable pharmaceutical concentrations to the urban-influenced site. In general, pharmaceutical concentrations increased during winter at both sites and decreased during spring and summer. Multiple regression analyses indicated that water column dissolved oxygen, the number of days since precipitation, and solar radiation influenced total pharmaceutical concentration in the urban-influenced site; whereas pH, chlorophyll a concentration, and total amount of rainfall in the previous 10 days influenced total pharmaceutical concentrations in the agriculturally-influenced site. Pharmaceutical concentrations were not correlated with sediment {delta}{sup 15}N across or within sites. However, sediment in the urban-influenced site had higher mean {delta}{sup 15}N signatures relative to sediment in the agriculturally-influenced site. These data indicate pharmaceuticals are persistent in aquatic ecosystems influenced by both agricultural and suburban activity. Pharmaceuticals are designed to have a physiological

NIM: A Node Influence Based Method for Cancer Classification

Directory of Open Access Journals (Sweden)

Yiwen Wang

2014-01-01

Full Text Available The classification of different cancer types owns great significance in the medical field. However, the great majority of existing cancer classification methods are clinical-based and have relatively weak diagnostic ability. With the rapid development of gene expression technology, it is able to classify different kinds of cancers using DNA microarray. Our main idea is to confront the problem of cancer classification using gene expression data from a graph-based view. Based on a new node influence model we proposed, this paper presents a novel high accuracy method for cancer classification, which is composed of four parts: the first is to calculate the similarity matrix of all samples, the second is to compute the node influence of training samples, the third is to obtain the similarity between every test sample and each class using weighted sum of node influence and similarity matrix, and the last is to classify each test sample based on its similarity between every class. The data sets used in our experiments are breast cancer, central nervous system, colon tumor, prostate cancer, acute lymphoblastic leukemia, and lung cancer. experimental results showed that our node influence based method (NIM is more efficient and robust than the support vector machine, K-nearest neighbor, C4.5, naive Bayes, and CART.

IMPACT OF INFLUENCERS FROM INSTAGRAM AND YOUTUBE ON THEIR FOLLOWERS

OpenAIRE

Vaibhavi Nandagiri; Leena Philip

2018-01-01

This study looks into the work of popular social media influencers and the impact they have on their followers. The social media influencer forums chosen are specific to YouTube and Instagram. The researcher seeks to understand if the work of an influencer while endorsing or reviewing a product has a positive effect on their followers. Sample size of minimum 100 were chosen and given a survey. A sample size of 10 between the age group of 18 – 21 years was selected for the experiment in which ...

Influence of a sampling review process for radiation oncology quality assurance in cooperative group clinical trials -- results of the Radiation Therapy Oncology Group (RTOG) analysis

International Nuclear Information System (INIS)

Martin, Linda A.; Krall, John M.; Curran, Walter J.; Leibel, Steven A.; Cox, James D.

1995-01-01

The Radiation Therapy Oncology Group (RTOG) designed a random sampling process and observed its influence upon radiotherapy review mechanisms in cooperative group clinical trials. The method of sampling cases for review was modeled from sampling techniques commonly used in pharmaceutical quality assurance programs, and applied to the initial (on-study) review of protocol cases. 'In control' (IC) status is defined for a given facility as the ability to meet minimum compliance standards. Upon achieving IC status, activation of the sampling process was linked to the rate of continued patient accrual for each participating institution in a given protocol. The sampling design specified that ≥ 30% cases not in compliance would be detected with 80% power. A total of 458 cases was analyzed for initial review findings in four RTOG Phase III protocols. Initial review findings were compared with retrospective (final) review results. Of the 458 cases analyzed, 370 underwent initial review at on-study, while 88 did not require review as they were enrolled from institutions that had demonstrated protocol compliance. In the group that had both initial and final review, (345(370)) (93%) were found to have followed the protocol or had a minor variation. Of the exempted cases, (79(88)) (90%) were found to be per protocol or a minor variant. The sampling process proved itself to be cost-effective and resulted in a noticeable reduction in the workload, thus providing an improved approach to resource allocation for the group. Continued evaluation of the sampling mechanism is appropriate as study designs and participants vary over time, and as more data become available to study. Further investigation of individual protocol compliance is appropriate to identify problems specific to new trial investigations

Mechanisms and interaction phenomena influencing releases in low- and medium-level waste disposal systems

International Nuclear Information System (INIS)

Brodersen, K.; Nilsson, K.

1990-11-01

The report covers work done 1986-1990 at Risoe National Laboratory as part of the third EC Research Programme on Radioactive Waste Management. Waste product characterization: Leaching and volume stability of cemented ion-exchange resins. Wet/dry cycling was found to be an important degradation mechanism. Hygroscopic properties of cemented and bituminized radioactive waste. Water uptake from the air can be an important release mechanism when waste containing soluble salts are disposed of by shallow land burial. Water uptake and swelling of bituminized waste including studies on water migration in bitumen membranes and measurements of swelling pressures. Ageing of bituminized products was demonstrated to result in increasing stiffness of the materials. Nickel ferrocyanide in precipitation sludge was found to be unstable in contact with concrete. Barrier material properties: The influence of the pore structure in concrete on the hydraulic or diffusive transport of water and ions through concrete barriers was investigated. The main parameter is the water/cement ratio. A theoretical interpretation is given. Healing of cracks in concrete barriers by precipitation of calcium carbonate was demonstrated experimentally and described by a simplified model. Transport of components between two thin plates of cement paste with different composition stored together in water was found to take place at a low rate. The structure of degraded cement paste was studied using SANS (small angle neutron scattering). Interaction phenomena: - Integral experiments with migration of radioisotopes from cemented waste through barriers made from kaolin, chalk or concrete were made under different external conditions. The results can be used for model validation and some preliminary work was done. (author) 16 tabs., 51 ills., 25 refs

Prescription drug samples--does this marketing strategy counteract policies for quality use of medicines?

Science.gov (United States)

Groves, K E M; Sketris, I; Tett, S E

2003-08-01

Prescription drug samples, as used by the pharmaceutical industry to market their products, are of current interest because of their influence on prescribing, and their potential impact on consumer safety. Very little research has been conducted into the use and misuse of prescription drug samples, and the influence of samples on health policies designed to improve the rational use of medicines. This is a topical issue in the prescription drug debate, with increasing costs and increasing concerns about optimizing use of medicines. This manuscript critically evaluates the research that has been conducted to date about prescription drug samples, discusses the issues raised in the context of traditional marketing theory, and suggests possible alternatives for the future.

Soft magnetic properties of bulk amorphous Co-based samples

International Nuclear Information System (INIS)

Fuezer, J.; Bednarcik, J.; Kollar, P.

2006-01-01

Ball milling of melt-spun ribbons and subsequent compaction of the resulting powders in the supercooled liquid region were used to prepare disc shaped bulk amorphous Co-based samples. The several bulk samples have been prepared by hot compaction with subsequent heat treatment (500 deg C - 575 deg C). The influence of the consolidation temperature and follow-up heat treatment on the magnetic properties of bulk samples was investigated. The final heat treatment leads to decrease of the coercivity to the value between the 7.5 to 9 A/m (Authors)

Sampling times influence the estimate of parameters in the Weibull dissolution model

Czech Academy of Sciences Publication Activity Database

Čupera, J.; Lánský, Petr; Šklubalová, Z.

2015-01-01

Roč. 78, Oct 12 (2015), s. 171-176 ISSN 0928-0987 Institutional support: RVO:67985823 Keywords : dissolution * Fisher information * rate constant * optimal sampling times Subject RIV: BA - General Mathematics Impact factor: 3.773, year: 2015

Channelling versus inversion

DEFF Research Database (Denmark)

Gale, A.S.; Surlyk, Finn; Anderskouv, Kresten

2013-01-01

Evidence from regional stratigraphical patterns in Santonian−Campanian chalk is used to infer the presence of a very broad channel system (5 km across) with a depth of at least 50 m, running NNW−SSE across the eastern Isle of Wight; only the western part of the channel wall and fill is exposed. W......−Campanian chalks in the eastern Isle of Wight, involving penecontemporaneous tectonic inversion of the underlying basement structure, are rejected....

A Two-Stage Method to Determine Optimal Product Sampling considering Dynamic Potential Market

Science.gov (United States)

Hu, Zhineng; Lu, Wei; Han, Bing

2015-01-01

This paper develops an optimization model for the diffusion effects of free samples under dynamic changes in potential market based on the characteristics of independent product and presents a two-stage method to figure out the sampling level. The impact analysis of the key factors on the sampling level shows that the increase of the external coefficient or internal coefficient has a negative influence on the sampling level. And the changing rate of the potential market has no significant influence on the sampling level whereas the repeat purchase has a positive one. Using logistic analysis and regression analysis, the global sensitivity analysis gives a whole analysis of the interaction of all parameters, which provides a two-stage method to estimate the impact of the relevant parameters in the case of inaccuracy of the parameters and to be able to construct a 95% confidence interval for the predicted sampling level. Finally, the paper provides the operational steps to improve the accuracy of the parameter estimation and an innovational way to estimate the sampling level. PMID:25821847

Laser ablation: Laser parameters: Frequency, pulse length, power, and beam charter play significant roles with regard to sampling complex samples for ICP/MS analysis

International Nuclear Information System (INIS)

Smith, M.R.; Alexander, M.L.; Hartman, J.S.; Koppenaal, D.W.

1996-01-01

Inductively coupled plasma mass spectrometry is used to investigate the influence of laser parameters with regard to sampling complex matrices ranging from relatively homogenous glasses to multi-phase sludge/slurry materials including radioactive Hanford tank waste. The resulting plume composition caused by the pulsed laser is evaluated as a function of wavelength, pulse energy, pulse length, focus, and beam power profiles. The author's studies indicate that these parameters play varying and often synergistic roles regarding quantitative results. (In a companion paper, particle transport and size distribution studies are presented.) The work described here will illustrate other laser parameters such as focusing and consequently power density and beam power profiles which are shown to influence precision and accuracy. Representative sampling by the LA approach is largely dependent on the sample's optical properties as well as laser parameters. Experimental results indicate that optimal laser parameters; short wavelength (UV), relatively low power (300 mJ), low-to-sub ns pulse lengths, and laser beams with reasonable power distributions (i.e., Gaussian or top-hat beam profiles) provide superior precision and accuracy. Remote LA-ICP/MS analyses of radioactive sludges are used to illustrate these optimal conditions laser ablation sampling

Sample design effects in landscape genetics

Science.gov (United States)

Oyler-McCance, Sara J.; Fedy, Bradley C.; Landguth, Erin L.

2012-01-01

An important research gap in landscape genetics is the impact of different field sampling designs on the ability to detect the effects of landscape pattern on gene flow. We evaluated how five different sampling regimes (random, linear, systematic, cluster, and single study site) affected the probability of correctly identifying the generating landscape process of population structure. Sampling regimes were chosen to represent a suite of designs common in field studies. We used genetic data generated from a spatially-explicit, individual-based program and simulated gene flow in a continuous population across a landscape with gradual spatial changes in resistance to movement. Additionally, we evaluated the sampling regimes using realistic and obtainable number of loci (10 and 20), number of alleles per locus (5 and 10), number of individuals sampled (10-300), and generational time after the landscape was introduced (20 and 400). For a simulated continuously distributed species, we found that random, linear, and systematic sampling regimes performed well with high sample sizes (>200), levels of polymorphism (10 alleles per locus), and number of molecular markers (20). The cluster and single study site sampling regimes were not able to correctly identify the generating process under any conditions and thus, are not advisable strategies for scenarios similar to our simulations. Our research emphasizes the importance of sampling data at ecologically appropriate spatial and temporal scales and suggests careful consideration for sampling near landscape components that are likely to most influence the genetic structure of the species. In addition, simulating sampling designs a priori could help guide filed data collection efforts.

The demagnetizing factors for the rectangular samples

International Nuclear Information System (INIS)

Akishin, P.G.; Gaganov, I.A.

1990-01-01

The influence of the demagnetization effect on the distribution of internal magnetic fields for finite samples is considered. The boundary integral method is used to compute the space distribution of the magnetic field in rectangular samples. On the basis of these calculations we compute the distribution of demagnetization factors in the sample for μSR experimental set-up with the real field geometry. The corresponding mathematical expectation and dispersion of this distribution are estimated. The results of the calculation are used in the analysis of the μSR data obtained for high T c superconductors. It is shown for these compounds that the correction to the penetration depth related to the broadening of the field distribution, is not more than 5%. 8 refs.; 2 figs.; 1 tab

Customers Demographics Influence on Usage of Retail Banking Channels

Directory of Open Access Journals (Sweden)

Neha GUPTA

2016-09-01

Full Text Available The study presents the usage of retail banking influenced by customers’ demographics of selected Public Sector Banks (PSBs of India. The study was based on primary data collected through structured questionnaire. The simple random sampling technique used for data collection for sample size 692. The study finds that public sector banks need to understand the usage pattern of an individual customer using delivery channel to add greater value to customers. Respondent age groups influence ATMs usage. Internet banking is majorly influenced by the customers’ demographics. Respondents’ age group and qualification influence mobile banking. Branch lobby kiosk is not influenced by any demographics. The identification of most influential demographic variable will help to build strong and effective cross-selling and up-selling of financial products and services. Our study was limited to the customers of PSBs of India. This study may be helpful to PSBs for enhancing effective usage of delivery channels.

Cultural influences on personality.

Science.gov (United States)

Triandis, Harry C; Suh, Eunkook M

2002-01-01

Ecologies shape cultures; cultures influence the development of personalities. There are both universal and culture-specific aspects of variation in personality. Some culture-specific aspects correspond to cultural syndromes such as complexity, tightness, individualism, and collectivism. A large body of literature suggests that the Big Five personality factors emerge in various cultures. However, caution is required in arguing for such universality, because most studies have not included emic (culture-specific) traits and have not studied samples that are extremely different in culture from Western samples.

Influence of color on acceptance and identification of flavor of foods by adults