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....

Influence of effective stress coefficient on mechanical failure of chalk

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.

2012-01-01

The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chal...... precise failure strength of chalk during changed stress state and under the influence of chemically reactive fluids during production of hydrocarbon and geological storage CO2....

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

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...

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 ...

New insight into the microtexture of chalks from NMR analysis

DEFF Research Database (Denmark)

Faÿ-Gomord, Ophélie; Soete, Jeroen; Katika, Konstantina

2016-01-01

An integrated petrographical and petrophysical study was carried out on a set of 35 outcrop chalk samples, covering a wide range of lithologies and textures. In this study various chalk rock-types have been characterized, in terms of microtextures and porous network, by integrating both geologica...

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

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.

Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

International Nuclear Information System (INIS)

Maruthi, Y. A.; Das, N. Lakshmana; Ramprasad, S.; Ram, S. S.; Sudarshan, M.

2015-01-01

The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk

Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

Energy Technology Data Exchange (ETDEWEB)

Maruthi, Y. A., E-mail: ymjournal2014@gmail.com [Associate professor, Dept of Environmental Studies, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Das, N. Lakshmana, E-mail: nldas9@gmail.com [Professor, Dept of Physics, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Ramprasad, S., E-mail: ramprasadsurakala@gmail.com [Research Scholar, Dept of Environmental science, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Ram, S. S., E-mail: tracebio@gmail.com [Research Scholar, Dept of Trace element research, UGC-DAE Consortium Centre, Kolkata centre India (India); Sudarshan, M., E-mail: sude@alpha.iuc.res.in [Scientist-F, Dept of Trace element research, UGC-DAE Consortium Centre, Kolkata centre India (India)

2015-08-28

The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk.

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

Ekofisk chalk: core measurements, stochastic reconstruction, network modeling and simulation

Energy Technology Data Exchange (ETDEWEB)

Talukdar, Saifullah

2002-07-01

This dissertation deals with (1) experimental measurements on petrophysical, reservoir engineering and morphological properties of Ekofisk chalk, (2) numerical simulation of core flood experiments to analyze and improve relative permeability data, (3) stochastic reconstruction of chalk samples from limited morphological information, (4) extraction of pore space parameters from the reconstructed samples, development of network model using pore space information, and computation of petrophysical and reservoir engineering properties from network model, and (5) development of 2D and 3D idealized fractured reservoir models and verification of the applicability of several widely used conventional up scaling techniques in fractured reservoir simulation. Experiments have been conducted on eight Ekofisk chalk samples and porosity, absolute permeability, formation factor, and oil-water relative permeability, capillary pressure and resistivity index are measured at laboratory conditions. Mercury porosimetry data and backscatter scanning electron microscope images have also been acquired for the samples. A numerical simulation technique involving history matching of the production profiles is employed to improve the relative permeability curves and to analyze hysteresis of the Ekofisk chalk samples. The technique was found to be a powerful tool to supplement the uncertainties in experimental measurements. Porosity and correlation statistics obtained from backscatter scanning electron microscope images are used to reconstruct microstructures of chalk and particulate media. The reconstruction technique involves a simulated annealing algorithm, which can be constrained by an arbitrary number of morphological parameters. This flexibility of the algorithm is exploited to successfully reconstruct particulate media and chalk samples using more than one correlation functions. A technique based on conditional simulated annealing has been introduced for exact reproduction of vuggy

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.

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...

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...

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.

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.

The surface reactivity of chalk (biogenic calcite) with hydrophilic and hydrophobic functional groups

Science.gov (United States)

Okhrimenko, D. V.; Dalby, K. N.; Skovbjerg, L. L.; Bovet, N.; Christensen, J. H.; Stipp, S. L. S.

2014-03-01

The surface properties of calcium carbonate minerals play an important role in a number of industrial and biological processes. Properties such as wettability and adsorption control liquid-solid interface behaviour and thus have a strong influence on processes such as biomineralisation, remediation of aquifers and oil recovery. We investigated how two model molecules of different polarity, namely water and ethanol, interact with reservoir and outcrop chalk samples and we compared their behaviour with that of pure, inorganically precipitated calcite. Thermodynamic quantities, such as the work of wetting, surface energy and isosteric adsorption enthalpy, were determined from vapour adsorption isotherms. The chalks were studied fresh and after extraction of organic residues that were originally present in these samples. The work of wetting correlates with the amount of organic matter present in the chalk samples but we observed a fundamental difference between the adsorption properties of chalk and pure, inorganically precipitated calcite toward the less polar, ethanol molecule. Further analysis of the chemical composition of the organic matter extracted from the chalk samples was made by gas chromatography (GC-MS). Monitoring surface composition by X-ray photoelectron spectroscopy (XPS) before and after extraction of the organic material, and with atomic force microscopy (AFM), showed that nanometer sized clay crystals observed on the chalk particle surfaces could be an important part of the reason for the differences. Removal of the extractable portion of the hydrocarbons liberates adsorption sites that have different wetting properties than the rest of the chalk and these have an energy distribution that is similar to clays. Thus, the results exemplify the complexity of biogenic calcite adsorption behaviour and demonstrate that chalk wetting in drinking water aquifers as well as oil reservoirs is controlled partly by the nanoparticles of clay that have grown on the

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.

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...

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.

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...

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.

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.

Porosity and sonic velocity depth trends of Eocene chalk in Atlantic Ocean: Influence of effective stress and temperature

DEFF Research Database (Denmark)

Awedalkarim, Ahmed; Fabricius, Ida Lykke

2014-01-01

We aimed to relate changes in porosity and sonic velocity data, measured on water-saturated Eocene chalks from 36 Ocean Drilling Program drill sites in the Atlantic Ocean, to vertical effective stress and thermal maturity. We considered only chalk of Eocene age to avoid possible influence...... not show or at least it is difficult to define a clear pore-stiffening contact cementation trend as the Ontong Java Plateau chalk. Mechanical compaction is the principal cause of porosity reduction (at shallow depths) in the studied Eocene chalk, at least down to about 5MPa Terzaghi׳s effective stress...

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

Permeability, porosity, dispersion-, diffusion-, and sorption characteristics of chalk samples from Erslev, Mors, Denmark

International Nuclear Information System (INIS)

Carlsen, L.; Batsberg, W.; Skytte Jensen, B.; Bo, P.

1981-08-01

A series of chalk samples from the cretaceous formation overlying the Erslev salt dome have been studied in order to establish permeabilities, porosities, dispersion-, diffusion-, and sorption characteristics of the chalk, Predominantly the investigations have been carried out by application of a liquid chromatographic technique. The chalk was found to be porous (epsilon approximately 0.4), however, of rather low permeability (k approximately 10 -7 cm/sec). It was found that the material exhibits a retarding effect on the migration of cationic species as Cs + , Sr 2+ , Co 2+ , and Eu 3+ , whereas anionic species as Cl - and TcO - 4 move with the water front. The geochemical implications are discussed. (author)

Biot Critical Frequency Applied as Common Friction Factor for Chalk with Different Pore Fluids and Temperatures

DEFF Research Database (Denmark)

Andreassen, Katrine Alling; Fabricius, Ida Lykke

2010-01-01

Injection of water into chalk hydrocarbon reservoirs has lead 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. Water has a significant softening effect on elastic...... and we propose that the fluid effect on mechanical properties of highly porous chalk may be the result of liquid‐solid friction. Applying a different strain or stress rate is influencing the rock strength and needs to be included. The resulting function is shown to relate to the material dependent...... and rate independent b-factor used when describing the time dependent mechanical properties of soft rock or soils. As a consequence it is then possible to further characterize the material constant from the porosity and permeability of the rock as well as from pore fluid density and viscosity which...

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...

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...

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 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...

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...

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 ...

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.

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

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...

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.

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.

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...

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...

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...

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)

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...

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

Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea

DEFF Research Database (Denmark)

Røgen, Birte; Fabricius, Ida Lykke

2002-01-01

specific surface area. Fifty-nine Tor and Ekofisk Formation chalk samples from five North Sea chalk reservoirs were investigated. All contain quartz and clay minerals, most commonly kaolinite and smectite, with trace amounts of illite. The contents of calcite and quartz are inversely correlated and both......)): calcite between 0.5 and 3.5, quartz about 5, kaolinite about 15, and smectite about 60....

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.)

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

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

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

The new Chalk River AMS ion source, sample changer and external sample magazine

International Nuclear Information System (INIS)

Koslowsky, V.T.; Bray, N.; Imahori, Y.; Andrews, H.R.; Davies, W.G.

1997-01-01

A new sample magazine, sample changer and ion source have been developed and are in routine use at Chalk River. The system features a readily accessible 40-sample magazine at ground potential that is external to the ion source and high-voltage cage. The samples are held in an inert atmosphere and can be individually examined or removed; they can be exchanged en masse as a complete magazine concurrent with an AMS measurement. On-line sample changing is done with a pneumatic rabbit transfer system employing two stages of differential pumping. At Chalk River this is routinely performed across a 200 kV potential. Sample positioning is precise, and hundreds of 36 Cl and 129 I samples have been measured over a period of several days without interruption or alteration of ion source operating conditions. (author)

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....

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

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)

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

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.

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.

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...

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...

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)

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.

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...

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...

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...

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)

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.

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.

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

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

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

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)

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.)

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.

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

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)

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

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

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...

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

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

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...

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...

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

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

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...

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...

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...

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...

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

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.

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)

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

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

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....

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

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)

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.

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

Influence of coal mine tips on the chalk aquifer. Sampling methods for three dimensional sulphate infiltration study

Energy Technology Data Exchange (ETDEWEB)

Barrez, F.; Mania, J. [Polytech' Lille, Dept. Genie Civil, UMR CNRS 8107 (LML), 59 - Villeneuve d' Ascq (France); Mansy, J.L. [Lille-1 Univ., Lab. de Sedimentologie et de Geodynamique, UMR CNRS 8110 (PBDS), 59 - Villeneuve d' Ascq (France); Piwakowski, B. [Ecole Centrale de Lille, Groupe Electronique Acoustique IEMN-DOAE, UMR CNRS 8520, 59 - Villeneuve d' Ascq (France)

2005-07-01

The coal basin of the Nord-Pas-de-Calais region (France) shows a very strong deterioration of the Chalk aquifer quality. In order to better model the hydro-dynamism and to improve knowledge on the chemical interactions, sampling according to depth of the groundwater is undertaken. The low-flow sampling and the profiles of the in-situ physicochemical parameters allow the observation of various vertical heterogeneities of the aquifer. The areas where the coal mine tips are localised appear very interesting to study. The sulphates released by the pyrite oxidation allow a 'artificial tracing' and give a visualization of the flow as well as information on the implied chemical processes between the oxidizing and reducing zones. (authors)

Influence of coal mine tips on the chalk aquifer. Sampling methods for three dimensional sulphate infiltration study

International Nuclear Information System (INIS)

Barrez, F.; Mania, J.; Mansy, J.L.; Piwakowski, B.

2005-01-01

The coal basin of the Nord-Pas-de-Calais region (France) shows a very strong deterioration of the Chalk aquifer quality. In order to better model the hydro-dynamism and to improve knowledge on the chemical interactions, sampling according to depth of the groundwater is undertaken. The low-flow sampling and the profiles of the in-situ physicochemical parameters allow the observation of various vertical heterogeneities of the aquifer. The areas where the coal mine tips are localised appear very interesting to study. The sulphates released by the pyrite oxidation allow a 'artificial tracing' and give a visualization of the flow as well as information on the implied chemical processes between the oxidizing and reducing zones. (authors)

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.

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%.

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

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.

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

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.

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)

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)

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

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

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

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)

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)

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

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

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

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.

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

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)

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

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)

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.

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)

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.

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...

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

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

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.

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.

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

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

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)

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.

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.

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

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...

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

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

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...

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

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...

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

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

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.)

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...

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.

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...

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...

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.

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...

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...

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

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.

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....

Oil recovery enhancement from fractured, low permeability reservoirs. [Carbonated Water

Energy Technology Data Exchange (ETDEWEB)

Poston, S.W.

1991-01-01

The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods.Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks.Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

Oil recovery enhancement from fractured, low permeability reservoirs. Annual report, October 1, 1990--September 31, 1991, Annex 4

Energy Technology Data Exchange (ETDEWEB)

Poston, S.W.

1991-01-01

The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods.Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks.Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

Oil Recovery Enhancement from Fractured, Low Permeability Reservoirs. [Carbonated Water

Science.gov (United States)

Poston, S. W.

1991-01-01

The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods. Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks. Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

Comments on nuclear reactor safety in Ontario

International Nuclear Information System (INIS)

1987-08-01

The Chalk River Technicians and Technologists Union representing 500 technical employees at the Chalk River Nuclear Laboratories of AECL submit comments on nuclear reactor safety to the Ontario Nuclear Safety Review. Issues identified by the Review Commissioner are addressed from the perspective of both a labour organization and experience in the nuclear R and D field. In general, Local 1568 believes Ontario's CANDU nuclear reactors are not only safe but also essential to the continued economic prosperity of the province

Hydrogeology of Mors

International Nuclear Information System (INIS)

Joshi, A.V.

1982-01-01

The covering layers protect the salt in the dome. Ground water velocities are small and the chalk exhibits good retention properties for the radionuclides. As ground water velocities below 500 m are small, knowledge of hydrogeology over only a small area over the dome is necessary (1 km horizontal transport takes about 15 mill. years). Additionally if the retention properties of the chalk together with radioactive decay are taken into account, it becomes obvious that the nuclides can travel only a few metres into the chalk, before they have decayed to safe radioactive levels. Therefore it does not appear to be necessary to investigate the hydrogeology beyond a few metres from the disposal area. The hydrogeological investigations that have been carried out, although they cover only a limited area, thus give an excellent and sufficient basis for a safety evaluation for determining the suitability of the Mors salt dome for waste disposal. (EG)

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.

An investigation of the suitability of the Chalk River site to host a geologic waste management facility for CRL's low and intermediate level wastes

International Nuclear Information System (INIS)

Thompson, P.; Baumgartner, P.; Chan, T.; Kitson, C.; Kozak, E.; Man, A.; Martino, J.; Stroes-Gascoyne, S.; Beaton, D.; Sharp, K.; Thivierge, R.

2011-01-01

Atomic Energy of Canada Limited (AECL) is investigating the suitability of the Chalk River Laboratories (CRL) site for hosting a Geologic Waste Management Facility (GWMF) as part of the Nuclear Legacy Liabilities Program (NLLP) funded through Natural Resources Canada (NRCan). The GWMF is envisioned to be an underground engineered-geological repository consisting of shafts, access tunnels and emplacement caverns located at a nominal depth of 500 to 1000 m in the bedrock at the CRL site. A 5-year-long pre-project study was started in 2006 to assess the feasibility of the bedrock at the CRL site to host a GWMF. The pre-project feasibility study began with a review of various previous geological investigations performed in the bedrock at the CRL site. The 2006-2010 pre-project feasibility study involved exploring the geoscience and engineering characteristics of the bedrock to depths of over one kilometre at the CRL site through surface investigations and the drilling and testing of seven new deep characterization boreholes into the CRL bedrock. The collected information and interpretations were used to construct three-dimensional (3D) deterministic computer models of the geology of the bedrock at the CRL site and surrounding area and of the associated groundwater-flow regime. In order to technically assess the suitability of the CRL site, the GWMF feasibility study has conservatively assumed that all of the legacy and forecast Low and Intermediate Level Waste (LILW) at CRL would report to it. The 3D deterministic models were used within a preliminary performance and safety assessment model to assess the long-term safety of a hypothetical GWMF at the CRL site on the basis of future radionuclide and toxic substance releases. Other items important to a preliminary performance and safety assessment include an inventory of CRL's radioactive wastes and other contaminants that could be placed in the GWMF, the creation of the engineered waste emplacement rooms and

Permeability prediction in chalks

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika

2011-01-01

The velocity of elastic waves is the primary datum available for acquiring information about subsurface characteristics such as lithology and porosity. Cheap and quick (spatial coverage, ease of measurement) information of permeability can be achieved, if sonic velocity is used for permeability p...... significantly using the effective specific surface as the fluid-flow concept. The FZI unit is appropriate for highly permeable sedimentary rocks such as sandstones and limestones that have small surface areas....

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.

Low-level radioactive river sediment particles originating from the Chalk river nuclear site carry a mixture of radionuclides and metals

Energy Technology Data Exchange (ETDEWEB)

Lind, Ole Christian; Cagno, Simone; Salbu, Brit [Norwegian University of Life Sciences - NMBU, Center of Excellence in Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Aas (Norway); Falkenberg, Gerald [Photon science, DESY, Hamburg (Germany); Janssens, Koen; Nuyts, Gert; Vanmeert, Frederik [AXIL, Department of Chemistry, University of Antwerpen (Belgium); Jaroszewicz, Jakub [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Priest, Nicholas D.; Audet, Marc [Nuclear Science Division, AECL Chalk River Laboratories (Canada)

2014-07-01

The Chalk River Laboratory of Atomic Energy of Canada Ltd., site is located on the Ottawa River approximately 200 km northwest of Ottawa, Canada. The site has two large research reactors: NRX, which operated from 1947 to 1991 and NRU, which continues to operate and is used to produce a significant fraction of the world's supply of medical isotopes. During the course of the operation of the NRX reactor small quantities of radioactive particles were discharged to the Ottawa River through a process sewer discharge pipe. These are now located in river bed sediments within a 0.08 km² area close to the discharge pipe. In the present study, selected particles were isolated from riverbed sediments. These were then characterized by environmental scanning electron microscopy with energy dispersive micro X-ray analysis (ESEM-EDX). This was undertaken to obtain information on particle size, structure and the distribution of elements across particle surfaces. Based on the results of ESEM-EDX, particles were selected for X-ray absorption nano-tomography analysis, which provides videos showing the 3D density distribution of the particles. Furthermore, 2D and 3D Synchrotron Radiation based X-ray techniques (micro-X-ray fluorescence; micro-XRF, micro-X-ray absorption near edge spectroscopy; micro-XANES and micro-X-ray diffraction; micro-XRD) with submicron resolution (beam size 0.5 μm) were employed to investigate the elemental and phase composition (micro-XRF/XRD) and oxidation states (micro-XANES) of matrix elements with high spatial resolution and sensitivity. Results show that the particles investigated so far varied according to: 1) <~40 μm diameter sized U fuel particles similar in structure to particles observed from Chernobyl and Krasnoyarsk-26 and 2) larger particles with diameters up to several hundred μm. The larger particles comprised a matrix of low density, sediment material with high density inclusions that contained a range of metals including Cu, Cr, As

Purification and solidification of reactor wastes at a Canadian nuclear generating station

International Nuclear Information System (INIS)

Buckley, L.P.; Burt, D.A.

1981-01-01

The study aimed at development and demonstration of volume reduction and solidification of CANDU reactor wastes has been underway at Chalk River Nuclear Laboratories in the Province of Ontario, Canada. The study comprises membrane separation processes, evaporator appraisal and immobilization of concentrated wastes in bitumen. This paper discusses the development work with a wiped-film evaporator and the successful completion of demonstration tests at Douglas Point Nuclear Generating Station. Heavy water from the moderator system was purified and wastes arising from pump bowl decontamination were immobilized in bitumen with the wiped-film evaporator that was used in the development tests at Chalk River

Reagent precipitation of copper ions from wastewater of machine-building factories

Science.gov (United States)

Porozhnyuk, L. A.; Lupandina, N. S.; Porozhnyuk, E. V.

2018-03-01

The article presents the results of reagent removal of copper ions from wastewater of machine-building factories. The urgency of the study is conditioned by the widening of the range of effective reagents through the implementation of industrial waste. The investigation covers mineralogical and fractional composition of chalk enrichment waste. In the work, the conditions of thermal activation of chalk enrichment waste used for reagent removal of copper ions from wastewater were elaborated. It was shown that the thermal activation of waste facilitates the increased treatment efficacy up to the set sanitation, hygiene and technological standards.

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

Performance of a novel synthetic Ca-based solid sorbent suitable for desulfurizing flue gases in a fluidized bed

Energy Technology Data Exchange (ETDEWEB)

Pacciani, R.; Muller, C.R.; Davidson, J.F.; Dennis, J.S.; Hayhurst, A.N. [University of Cambridge, Cambridge (United Kingdom). Dept. of Chemical Engineering & Biotechnology

2009-08-05

The extent and mechanism of sulfation and carbonation of limestone, dolomite, and chalk, were compared with a novel, synthetic sorbent (85 wt % CaO and 15 wt % Ca{sub 12}A{sub l14}O{sub 33}), by means of experiments undertaken in a small, electrically heated fluidized bed. The sorbent particles were used either (I) untreated, sieved to two particle sizes and reacted with two different concentrations of SO{sub 2}, or (ii) after being cycled 20 times between carbonation, in 15 vol % CO{sub 2} in N2, and calcination, in pure N2, at 750 degrees C. The uptake of untreated limestone and dolomite was generally low (<0.2 g(SO{sub 2})/g(sorbent)), confirming previous results, However, the untreated chalk and the synthetic sorbent were found to be substantially more reactive with SO{sub 2}, and their final uptake was significantly higher (>0.5 g(SO{sub 2})/g(sorbent)) and essentially independent of the particle size. Here, comparisons are made on the basis of the sorbents in the calcined state. The capacities for the uptake of SO{sub 2}, on a basis of unit mass of calcined sorbent, were comparable for the chalk and the synthetic sorbent. However, previous work has demonstrated the ability of the synthetic sorbent to retain its capacity for CO{sub 2} over many cycles of carbonation and calcination: much more so than natural sorbents such as chalk and limestone. Accordingly, the advantage of the synthetic sorbent is that it could be used to remove CO{sub 2} from flue gases and, at the end of its life, to remove SO{sub 2} on a once-through basis.

Enhanced Oil Recovery from Oil-wet Carbonate Rock by Spontaneous Imbibition of Aqueous Surfactant Solutions

Energy Technology Data Exchange (ETDEWEB)

Standnes, Dag Chun

2001-09-01

The main theme of this thesis is an experimental investigation of spontaneous imbibition (SI) of aqueous cationic surfactant solution into oil-wet carbonate (chalk- and dolomite cores). The static imbibition process is believed to represent the matrix flow of oil and water in a fractured reservoir. It was known that aqueous solution of C{sub 12}-N(CH{sub 3}){sub 3}Br (C12TAB) was able to imbibe spontaneously into nearly oil-wet chalk material, but the underlying mechanism was not understood. The present work was therefore initiated, with the following objectives: (1) Put forward a hypothesis for the chemical mechanism underlying the SI of C12TAB solutions into oil-wet chalk material based on experimental data and (2) Perform screening tests of low-cost commercially available surfactants for their ability to displace oil by SI of water into oil-wet carbonate rock material. It is essential for optimal use of the surfactant in field application to have detailed knowledge about the mechanism underlying the SI process. The thesis also discusses some preliminary experimental results and suggests mechanisms for enhanced oil recovery from oil-wet carbonate rock induced by supply of thermal energy.

The Skælskør structure in eastern Denmark – wrench-related anticline or primary Late Cretaceous sea-floor topography?

DEFF Research Database (Denmark)

Surlyk, Finn; Boldreel, Lars Ole; Lykke-Andersen, Holger

2010-01-01

seismic studies of the Chalk Group in Øresund and Kattegat have shown that similar highs actually represent topographic highs on the Late Cretaceous – Danian seafloor formed by strong contourparallel bottom currents. Reflection seismic data collected over the Skælskør structure in order to test...... the Ringkøbing Fyn High into the Danish Basin. The elevated position is maintained due to reduced subsidence as compared with the Danish Basin north of the high. The hypothesis of wrench tectonics as origin can be refuted. The seismic data show that the upper part of the Chalk Group is characterised by irregular...

76 FR 72405 - Notice of Receipt of Requests to Voluntarily Cancel Certain Pesticide Registrations

Science.gov (United States)

2011-11-23

... Wood Preservative. 2-(Thiocyanomethylthio) benzothiazole Methylene bis (thiocyanate). 065092-00001 ZE... Cleanser. dihydrate. 075015-00001 Dead-Fast Insecticide Chalk Tralomethrin. 080697-00009 Chlorpyrifos...

77 FR 8863 - Product Cancellation Order for Certain Pesticide Registrations

Science.gov (United States)

2012-02-15

...-00001 X-100 Natural Seal Wood 2-(Thiocyanomethylthio) benzothiazole, Preservative. Methylene bis... dichloroisocyanurate dihydrate. Disinfectant Cleanser. 075015-00001 Dead-Fast Insecticide Chalk Tralomethrin. 080697...

Oil recovery enhancement from fractured, low permeability reservoirs. Part 2, Annual report, October 1, 1990--September 31, 1991

Energy Technology Data Exchange (ETDEWEB)

Poston, S.W.

1991-12-31

The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990--1991 year may be summarized as follows: Geological Characterization -- Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. These results of these efforts were directly applied to the development of production decline type curves applicable to a dual fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. (VSP) Vertical-Seismic Profile data was used to use shear-wave splitting concepts to estimate fracture orientations. Several programs were to be written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods. Development of the (EOR) Enhanced Oil Recovery Imbibition Process -- Laboratory displacement as well as MRI and CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery of an oil saturated, low permeability core material, when compared to that of a normal brine imbibition displacement process. A study of oil recovery by the application of a cyclic carbonated water imbibition process, followed by reducing the pressure below the bubble point of the CO{sub 2}-water solution, indicated the possibility of alternate and new enhanced recovery method. The installation of an artificial solution gas drive significantly increased oil recovery. The extent and arrangement of micro-fractures in Austin Chalk horizontal cores was mapped with CT scanning techniques. The degree of interconnection of the micro-fractures was easily visualized.

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

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

Geohydrologic-engineering geology evaluation of the Selma Group in western Alabama and northeast Mississippi for possible radioactive waste disposal

International Nuclear Information System (INIS)

Gonzales, S.

1975-06-01

The following topics are discussed: regional stratigraphy, lithologic characteristic-chalk sequences, structural geology settting, earthquakes and historical seismicity, regional geomorphology, recovery of geological resources, and groundwater hydrology

Soil treatment to remove uranium and related mixed radioactive contaminants. Final report September 1992--October 1995

International Nuclear Information System (INIS)

1996-07-01

A research and development project to remove uranium and related radioactive contaminants from soil by an ultrasonically-aided chemical leaching process began in 1993. The project objective was to develop and design, on the basis of bench-scale and pilot-scale experimental studies, a cost-effective soil decontamination process to produce a treated soil containing less than 35 pCi/g. The project, to cover a period of about thirty months, was designed to include bench-scale and pilot-scale studies to remove primarily uranium from the Incinerator Area soil, at Fernald, Ohio, as well as strontium-90, cobalt-60 and cesium-137 from a Chalk River soil, at the Chalk River Laboratories, Ontario. The project goal was to develop, design and cost estimate, on the basis of bench-scale and pilot-scale ex-situ soil treatment studies, a process to remove radionuclides form the soils to a residual level of 35 pCi/g of soil or less, and to provide a dischargeable water effluent as a result of soil leaching and a concentrate that can be recovered for reuse or solidified as a waste for disposal. In addition, a supplementary goal was to test the effectiveness of in-situ soil treatment through a field study using the Chalk River soil

Proceedings of the international conference on CANDU fuel

International Nuclear Information System (INIS)

Hastings, I.J.

1986-01-01

These proceedings contain full texts of all paper presented at the first International Conference on CANDU Fuel. The Conference was organized and hosted by the Chalk River Branch of the Canadian Nuclear Society and utilized Atomic Energy of Canada Limited's facilities at Chalk River Nuclear Laboratories. Previously, informal Fuel Information Meetings were used in Canada to allow the exchange of information and technology associated with CANDU. The Chalk River conference was the first open international forum devoted solely to CANDU and included representatives of overseas countries with current or potential CANDU programs, as well as Canadian participants. The keynote presentation was given by Dr. J.B. Slater, who noted the correlation between past successes in CANDU fuel cycle technology and the co-operation between researchers, fabricators and reactor owner/operators in all phases of the fuel cycle, and outlined the challenges facing the industry today. In the banquet address, Dr. R.E. Green described the newly restructured AECL Research Company and its mission which blends traditional R and D with commercial initiatives. Since this forum for fuel technology has proven to be valuable, a second International CANDU Fuel Conference is planned for the fall of 1989, again sponsored by the Canadian Nuclear Society

Rõõm muusikast / Mati Märtin

Index Scriptorium Estoniae

Märtin, Mati

2005-01-01

Ülestõusmispühade-kontsertidest Tallinna kirikutes: Päästearmee Londoni puhkpilliorkestri Chalk Farm Band kontserdist Kaarli kirikus, Eesti Muusikaakadeemia õpilaste kontserdist Jaani kirikus, Leedsi Filharmoonia Segakoori kontserdist Kaarli kirikus

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)

Cliff stability assessment using electrical resistivity tomography at the historic WWII D-Day invasion site, Pointe du Hoc, France

Science.gov (United States)

Everett, M. E.; Udphuay, S.; Warden, R.

2007-05-01

The 1944 D-Day invasion site at Pointe du Hoc, Normandy, France is an important WWII battlefield and cultural resource but is at risk from chalk cliff collapse. The American Battle Monuments Commission tasked us to evaluate the geohazard to the observation post and other cliff-side buildings of historical significance. Geophysical multi-electrode resistivity profiling is used to study cliff stability and the condition of the observation- post foundations. Preliminary 2-D geological interpretations are provided of individual profiles. The copious steel, concrete and void spaces at the site renders hydrogeological interpretation challenging but tractable. The cliff face appears to be relatively intact and well-drained. Several routes taken by groundwater into fractures within the chalk were identified mainly on the western side of the site. The eastern side is drier and somewhat sheltered from the Atlantic storms but may contain large void spaces that could efficiently transmit groundwater flow during heavy precipitation events, thereby imperiling the major antiaircraft gun emplacement occupied by Col. Rudder in the early days of the Allied invasion. The forward German observation post perched close to the sea stack, which now hosts the U.S. Ranger memorial, may be moving with the soil and not securely anchored to bedrock. A complex failure mechanism is identified as a combination of groundwater dissolution of the fractured chalk and sea wave attack at the cliff base.

Irradiation of lithium-based ceramics for fusion blanket application

International Nuclear Information System (INIS)

Hastings, I.J.; Miller, J.M.; Verrall, R.A.; Bokwa, S.R.; Rose, D.H.

1986-06-01

Unvented CREATE (Chalk River Experiment to Assess Tritium Emission) tests have shown that under reducing conditions, most of the tritium (greater than 70%) is released from LiAlO 2 and Li 2 O as HT or T 2 ; the balance as HTO or T 2 O. Residual tritium is very small, less than 0.02%. Varying the sweep gas composition has a dramatic effect on the form of tritium released. With a quartz extraction tube during post- irradiation heating, a He sweep gas results in 10-30% release as HT or T 2 ; with a He-1%H 2 sweep gas, greater than 60% release as HT is achieved. The effect of extraction tube material is also significant. Using pure He sweep gas, a quartz extraction tube results in 10-30% release as HT or T 2 ; stainless steel produces 80-95% as HT or T 2 . Chalk River and CEA (Saclay) - fabricated LiAlO 2 behaved similarly to that from ANL in these tests. The first vented test at Chalk River, CRITIC-I, planned for 1986/87, will examine ANL-fabricated Li 2 O, 0.3 wt% 6 Li, 30 mm ID, 40 mm OD annular pellets, in a six-month irradiation at 700-1200 K, varying the sweep gas, with on-line HT/HTO measurement

Progress report: Physical Sciences - TASCC Division, 1992 July 01 -December 31

Energy Technology Data Exchange (ETDEWEB)

Hardy, J C [ed.

1993-05-01

This report summarizes operations and research activities in the Nuclear Physics Branch and the TASCC Accelerators and Development Branch at Chalk River Laboratories during the last half of 1992. 27 figs., 10 tabs.

Пираты третьего тысячелетия / коммент. Питер Чалк, Гордан Ван Хук

Index Scriptorium Estoniae

2009-01-01

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

Progress report: Physical Sciences - TASCC Division, 1992 July 01 -December 31

International Nuclear Information System (INIS)

Hardy, J.C.

1993-05-01

This report summarizes operations and research activities in the Nuclear Physics Branch and the TASCC Accelerators and Development Branch at Chalk River Laboratories during the last half of 1992. 27 figs., 10 tabs

Progress report: Physical Sciences - Physics Division, 1992 July 01 -December 31

Energy Technology Data Exchange (ETDEWEB)

Ungrin, J; Kim, S M; Sears, V F [eds.

1993-03-01

This report summarizes operations and research activities in the Accelerator Physics, Neutron and Condensed Matter Science and Theoretical Physics branches at Chalk River Laboratories during the last half of 1992. 21 figs., 3 tabs.

Progress report: Physical Sciences - Physics Division, 1992 July 01 -December 31

International Nuclear Information System (INIS)

Ungrin, J.; Kim, S.M.; Sears, V.F.

1993-03-01

This report summarizes operations and research activities in the Accelerator Physics, Neutron and Condensed Matter Science and Theoretical Physics branches at Chalk River Laboratories during the last half of 1992. 21 figs., 3 tabs

Nickel Allergy

Science.gov (United States)

... in many everyday items, such as coins, zippers, cellphones and eyeglass frames. It may take repeated or ... hooks Belt buckles Eyeglass frames Coins Metal tools Cellphones Keys Military "dog-tag" ID Chalk Medical devices ...

The role of major forest fires on rock physical decay in a Mediterranean environment

Science.gov (United States)

Shtober-Zisu, Nurit; Tessler, Naama; Tsatskin, Alexander; Greenbaum, Noam

2017-04-01

Massive destruction of carbonate rocks occurred on the slopes of Mt. Carmel (Israel), during a severe forest fire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80%-100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units—various types of chalk, limestone, and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies, as 85%-95% of the flakes were detached in the form of blades, plates, and slabs. The extent of the physical disruption depends on rock composition: the most severe response was found in the chalk formations which are covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. Scorched and blackened faces under the upper layer of spalls provide strong evidence that chalk breakdown took place at an early stage of the fire. The extreme response of the chalks can be explained by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari was removed, the more brittle underlying chalk is exposed to erosion. These flakes seem to play an important role in reforming the soil after the fire, especially by increasing the coarse particles percentage. These, in spite of the absence of vegetation cover, improve soil infiltration and percolation rates and cause long-term changes to the hydrological regime. It is difficult to estimate the frequency of high-intensity fires in the Carmel region over the past 2-3 million years, as well as the extension and density of the vegetation. It is even harder to assess the frequency of fires (and the destruction) of a single rock outcrop. Our findings show that rock outcrop may lose even 20 cm of its thickness in a single fire. This

Geodynamic and petrophysical modelling in the Kraka area

International Nuclear Information System (INIS)

Frykman, P.

2001-01-01

The present report has been prepared with the aim of presenting a model for the burial history of the chalk section in the Kraka field based on seismic mapping, data from wells, backstripping and decompaction. The parameters and models for the petrophysical properties are also presented in the perspective of being usable in dynamic modelling. The present geological model is based on data originating from an existing study, and does therefore not include more recent well data or additional seismic data. The model is intended to be used for initialising the development of geodynamic flow modelling, and the model will therefore be updated and refined as the project processes. The burial history of the Kraka area will be used to guide the development of reservoir parameters in the chalk section through time. (BA)

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)

A preliminary study of synchrotron light sources for x-ray lithography

International Nuclear Information System (INIS)

Hoffmann, C.R.; Bigham, C.B.; Ebrahim, N.A.; Sawicki, J.A.; Taylor, T.

1989-02-01

A preliminary study of synchrotron light sources has been made, primarily oriented toward x-ray lithography. X-ray lithography is being pursued vigorously in several countries, with a goal of manufacturing high-density computer chips (0.25 μm feature sizes), and may attain commercial success in the next decade. Many other applications of soft x-rays appear worthy of investigation as well. The study group visited synchrotron radiation facilities and had discussions with members of the synchrotron radiation community, particularly Canadians. It concluded that accelerator technology for a conventional synchrotron light source appropriate for x-ray lithography is well established and is consistent with skills and experience at Chalk River Nuclear Laboratories. Compact superconducting systems are being developed also. Their technical requirements overlap with capabilities at Chalk River. (32 refs)

Waste minimization at Chalk River Laboratories

Energy Technology Data Exchange (ETDEWEB)

Kranz, P.; Wong, P.C.F. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2011-07-01

Waste minimization supports Atomic Energy of Canada Limited (AECL) Environment Policy with regard to pollution prevention and has positive impacts on the environment, human health and safety, and economy. In accordance with the principle of pollution prevention, the quantities and degree of hazard of wastes requiring storage or disposition at facilities within or external to AECL sites shall be minimized, following the principles of Prevent, Reduce, Reuse, and Recycle, to the extent practical. Waste minimization is an important element in the Waste Management Program. The Waste Management Program has implemented various initiatives for waste minimization since 2007. The key initiatives have focused on waste reduction, segregation and recycling, and included: 1) developed waste minimization requirements and recycling procedure to establish the framework for applying the Waste Minimization Hierarchy; 2) performed waste minimization assessments for the facilities, which generate significant amounts of waste, to identify the opportunities for waste reduction and assist the waste generators to develop waste reduction targets and action plans to achieve the targets; 3) implemented the colour-coded, standardized waste and recycling containers to enhance waste segregation; 4) established partnership with external agents for recycling; 5) extended the likely clean waste and recyclables collection to selected active areas; 6) provided on-going communications to promote waste reduction and increase awareness for recycling; and 7) continually monitored performance, with respect to waste minimization, to identify opportunities for improvement and to communicate these improvements. After implementation of waste minimization initiatives at CRL, the solid waste volume generated from routine operations at CRL has significantly decreased, while the amount of recyclables diverted from the onsite landfill has significantly increased since 2007. The overall refuse volume generated at CRL (including solid radioactive waste, inactive waste and recyclables) decreased by 14% from 2007 to 2010. It should be noted that the workforce at CRL increased by approximately 15% during the same period. When considering the refuse volume data on a per capita basis, the volume of overall refuse per person was reduced from 3.03 m{sup 3}/person in 2007 to 2.25 m{sup 3}/person in 2010. This represents a 26% reduction in refuse in three years. This paper describes the waste minimization initiatives and the achievements at CRL in details, and also the planned initiatives in future. (author)

Waste minimization at Chalk River Laboratories

International Nuclear Information System (INIS)

Kranz, P.; Wong, P.C.F.

2011-01-01

Waste minimization supports Atomic Energy of Canada Limited (AECL) Environment Policy with regard to pollution prevention and has positive impacts on the environment, human health and safety, and economy. In accordance with the principle of pollution prevention, the quantities and degree of hazard of wastes requiring storage or disposition at facilities within or external to AECL sites shall be minimized, following the principles of Prevent, Reduce, Reuse, and Recycle, to the extent practical. Waste minimization is an important element in the Waste Management Program. The Waste Management Program has implemented various initiatives for waste minimization since 2007. The key initiatives have focused on waste reduction, segregation and recycling, and included: 1) developed waste minimization requirements and recycling procedure to establish the framework for applying the Waste Minimization Hierarchy; 2) performed waste minimization assessments for the facilities, which generate significant amounts of waste, to identify the opportunities for waste reduction and assist the waste generators to develop waste reduction targets and action plans to achieve the targets; 3) implemented the colour-coded, standardized waste and recycling containers to enhance waste segregation; 4) established partnership with external agents for recycling; 5) extended the likely clean waste and recyclables collection to selected active areas; 6) provided on-going communications to promote waste reduction and increase awareness for recycling; and 7) continually monitored performance, with respect to waste minimization, to identify opportunities for improvement and to communicate these improvements. After implementation of waste minimization initiatives at CRL, the solid waste volume generated from routine operations at CRL has significantly decreased, while the amount of recyclables diverted from the onsite landfill has significantly increased since 2007. The overall refuse volume generated at CRL (including solid radioactive waste, inactive waste and recyclables) decreased by 14% from 2007 to 2010. It should be noted that the workforce at CRL increased by approximately 15% during the same period. When considering the refuse volume data on a per capita basis, the volume of overall refuse per person was reduced from 3.03 m 3 /person in 2007 to 2.25 m 3 /person in 2010. This represents a 26% reduction in refuse in three years. This paper describes the waste minimization initiatives and the achievements at CRL in details, and also the planned initiatives in future. (author)

Non-destructive testing at Chalk River

International Nuclear Information System (INIS)

Hilborn, J.W.

1976-01-01

In 1969 CRNL recognized the need for a strong group skilled in non-destructive test procedures. Within two years a new branch called Quality Control Branch was staffed and working. This branch engages in all aspects of non-destructive testing including development of new techniques, new applications of known technology, and special problems in support of operating reactors. (author)

Elastic behaviour of North Sea chalk

DEFF Research Database (Denmark)

Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.

2007-01-01

-consistent approximation, which here represents the unrelaxed scenario where the pore spaces of the rock are assumed to be isolated, and the Gassmann theory, which assumes that pore spaces are connected, as tools for predicting the effect of hydrocarbons from the elastic properties of brine-saturated North Sea reservoir...

27 CFR 9.52 - Chalk Hill.

Science.gov (United States)

2010-04-01

... Quadrangle Map”; (10) Then northerly for approximately 1.3 miles along Mark West Road (which becomes Porter Creek Road), then northeasterly for approximately 1.7 miles on Porter Creek Road to its intersection with the unnamed medium duty road that parallels Porter Creek in Section 12, T. 8 N., R. 8 W.; then...

TASCC newsletter volume 6 no. 6

International Nuclear Information System (INIS)

Thomson, L.

1992-06-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue is a report on operator training, operating record and facility report and a listing of experiments conducted in June

Smart waterflooding in carbonate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Zahid, A.

2012-02-15

During the last decade, smart waterflooding has been developed into an emerging EOR technology both for carbonate and sandstone reservoirs that does not require toxic or expensive chemicals. Although it is widely accepted that different salinity brines may increase the oil recovery for carbonate reservoirs, understanding of the mechanism of this increase is still developing. To understand this smart waterflooding process, an extensive research has been carried out covering a broad range of disciplines within surface chemistry, thermodynamics of crude oil and brine, as well as their behavior in porous media. The main conclusion of most previous studies was that it is the rock wettability alteration towards more water wetting condition that helps improving the oil recovery. In the first step of this project, we focused on verifying this conclusion. Coreflooding experiments were carried out using Stevens Klint outcrop chalk core plugs with brines without sulfate, as well as brines containing sulfate in different concentrations. The effects of temperature, injection rate, crude oil composition and different sulfate concentrations on the total oil recovery and the recovery rate were investigated. Experimental results clearly indicate improvement of the oil recovery without wettability alteration. At the second step of this project, we studied crude oil/brine interactions under different temperatures, pressures and salinity conditions in order to understand mechanisms behind the high salinity waterflooding. Our results show, in particular that sulfate ions may help decreasing the crude oil viscosity or formation of, seemingly, an emulsion phase between sulfate-enriched brine and oil at high temperature and pressure. Experimental results indicate that crude oils interact differently with the same brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments

NPP Grassland: Beacon Hill, U.K., 1972-1993, R1

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains two ASCII text files, one providing productivity measurements for a chalk grassland on Beacon Hill, West Sussex, U.K. (50.92 N, -0.85 W) and...

TASCC newsletter volume 6 no. 11

International Nuclear Information System (INIS)

Thomson, L.

1992-01-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this issue is a report on Canadians at the Eurogam spectrometer, cyclotron beam report, facility report and operating record, a listing of experiments conducted

TASCC newsletter volume 9 no. 6

International Nuclear Information System (INIS)

Thomson, L.

1995-06-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue of TASCC is an update of the facility, TASCC workshop on international success and a listing of Junes's experiments. 1 fig

TASCC newsletter volume 5 no. 5

International Nuclear Information System (INIS)

Thomson, L.

1991-05-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this May issue is information on a workshop for material science studies, a facility report and operating record and the experiments conducted. 1 fig

Automated extraction of faults and porous reservoir bodies. Examples from the Vallhall Field

Energy Technology Data Exchange (ETDEWEB)

Barkved, Olav Inge; Whitman, Doug; Kunz, Tim

1998-12-31

The Norwegian Vahall field is located 250 km South-West of Stavanger. The production is primarily from the highly porous and fractured chalk, the Tor formation. Fractures, evidently play a significant role in enhancing flow properties as well as production rates, are significantly higher than expected from matrix permeability alone. The fractures are primarily tectonically induced and related to faulting. Syn-depositional faulting is believed to be a controlling factor on reservoir thickness variations observed across the field. Due to the low acoustic contrast and weak appearance of the highly porous chalk, direct evidence of faulting in well bore logs is limited. The seismic data quality in the most central area of the field is very poor due to tertiary gas charging, but in the flank area of the field, the quality is excellent. 1 ref., 5 figs.

TASCC newsletter volume 9 no. 6

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1995-06-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue of TASCC is an update of the facility, TASCC workshop on international success and a listing of Junes`s experiments. 1 fig.

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)

TASCC newsletter volume 8 no. 7

International Nuclear Information System (INIS)

Thomson, L.

1994-07-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this July issue of TASCC is an update of the facility,news on TASCC personnel, results of a coulomb-excitation and a listing of July's experiments. 4 figs

Progress report - Physical and Environmental Sciences - TASCC Division -1995 January 1 to June 30

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-08-01

Included in this progress report of the TASCC division at Chalk River Nuclear Laboratories is the research and development being carried out at this time and a listing of the relevant publications, reports. lectures and conference contributions. 15 tabs. 19 figs.

Physics case for a multiparticle detector system

International Nuclear Information System (INIS)

Horn, Dag.

1984-04-01

This report is an examination of the physics which would be accessible to a large multiparticle detector system when used with heavy ion beams of 10 to 50 MeV/u from the Chalk River Tandem Accelerator Superconducting Cyclotron Complex (TASCC)

Progress report, Physics Division, April 1 to June 30, 1975

International Nuclear Information System (INIS)

1975-08-01

The operation and research purposes of the Chalk River MP tandem accelerator are described. Besides programs in nuclear and solid state physics, research is carried out on improved radiation detectors and mathematical support of on-going programs. (E.C.B.)

Progress report - Physical and Environmental Sciences - TASCC Division -1995 January 1 to June 30

International Nuclear Information System (INIS)

1995-08-01

Included in this progress report of the TASCC division at Chalk River Nuclear Laboratories is the research and development being carried out at this time and a listing of the relevant publications, reports. lectures and conference contributions. 15 tabs. 19 figs

TASCC newsletter volume 9 no. 12

International Nuclear Information System (INIS)

Thomson, L.

1995-12-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this December issued of TASCC is an update of the facility, a year -end review of TASCC by the director and a listing of December's experiments. 1 fig

Development of aluminosilicate and borosilicate glasses as matrices for CANDU high-level waste

International Nuclear Information System (INIS)

Strathdee, G.G.; McIntyre, N.S.; Taylor, P.

1979-01-01

This paper covers the results of analyses of two radioactive nepheline syenite glass blocks recovered from in-ground leaching experiments at the Chalk River Nuclear Laboratories. Current research on borosilicate glasses for immobilization of high-level waste is also described

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

Hydroecological impacts of climate change modelled for a lowland UK wetland

Science.gov (United States)

House, Andrew; Acreman, Mike; Sorensen, James; Thompson, Julian

2015-04-01

Conservation management of wetlands often rests on modifying hydrological functions to establish or maintain desired flora and fauna. Hence the ability to predict the impacts of climate change is highly beneficial. Here, the physically based, distributed model MIKE SHE was used to simulate hydrology for the Lambourn Observatory at Boxford, UK. This comprises a 10 ha lowland riparian wetland protected for conservation, where the degree of variability in the peat, gravel and chalk geology has clouded hydrological understanding. Notably, a weathered layer on the chalk aquifer surface seals it from overlying deposits, yet is highly spatially heterogeneous. Long-term monitoring yielded observations of groundwater and surface water levels for model calibration and validation. Simulated results were consistent with observed data and reproduced the effects of seasonal fluctuations and in-channel macrophyte growth. The adjacent river and subsidiary channel were found to act as head boundaries, exerting a general control on water levels across the site. Discrete areas of groundwater upwellings caused raised water levels at distinct locations within the wetland. These were concurrent to regions where the weathered chalk layer is absent. To assess impacts of climate change, outputs from the UK Climate Projections 2009 ensemble of global climate models for the 2080s are used to obtain monthly percentage changes in climate variables. Changes in groundwater levels were taken from a regional model of the Chalk aquifer. Values of precipitation and evapotranspiration were seen to increase, whilst groundwater levels decreased, resulting in the greater dominance of precipitation. The discrete areas of groundwater upwelling were seen to diminish or disappear. Simulated water levels were linked to specific requirements of wetland plants using water table depth zone diagrams. Increasing depth of winter and summer groundwater levels leads to a loss of Glyceria maxima and Phragmites

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

TASCC newsletter volume 8 no. 4

International Nuclear Information System (INIS)

Thomson, L.

1994-04-01

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, news on the Penning-trap spectrometer, educators at CRL, AECB inspection and a listing of April's experiments. 1 fig

AJER VOLUME I-JANUARY 2013

African Journals Online (AJOL)

Dr Kazungu

However, weaknesses in tax administration, imprudent tax exemptions, high .... principles for attaining sound social budgeting, namely: equity, efficiency, ... expenditures by governments (Botswana, Malaysia, Sri Lanka, Chile and ...... Chalk, N and R. Hemming (2000), “Assessing Fiscal Space in Theory and Practice,” IMF.

TASCC newsletter volume 7 no. 12

International Nuclear Information System (INIS)

Thomson, L.

1993-12-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this December issue of TASCC is an update of the facility, a year end review by the director and a listing of experiments carried out in December. 3 figs

Upper Campanian−Maastrichtian holostratigraphy of the eastern Danish Basin

DEFF Research Database (Denmark)

Surlyk, Finn; Rasmussen, Susanne Lil; Boussaha, Myriam

2013-01-01

of changes in chalk facies, water depths and sea-water temperatures. Combined lithological data, a suite of petrophysical logs including gamma ray (GR) logs, nannofossil and dinoflagellate palaeontology, stable carbon isotopes, seismic reflection and refraction sections form the basis for the definition...

TASCC newsletter volume 9 no. 8

International Nuclear Information System (INIS)

Thomson, L.

1995-08-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this August issue of TASCC is an update of the facility, improvement in memory effects by the AMS at TASCC, personnel news and a listing of August's experiments. 3 figs

Surface-Tolerant Coatings for Aircraft Hangars, Flight Control Tower, and Deluge Tanks at Fort Campbell

Science.gov (United States)

2007-06-01

to chalking. Fluorinated polymers are recognized as the most durable coatings in terms of preservation of appearance. Architectural building panels...phosphate) 19.4 Percent by Weight Film-Former phenolic varnish 55.3 Percent by Weight Antioxidant butylated hydroxytoluene (BHT) 0.43 Percent

Progress report physics division, 1983 July 1 - December 31

International Nuclear Information System (INIS)

1984-02-01

This report summarizes work carried out during the last half of 1983 in the Physics Division of the Chalk River Nuclear Laboratories in the areas of superconducting cyclotron facility development, nuclear physics research, applied physics, solid state physics, and applied mathematics and computation

TASCC newsletter volume 7 no. 11

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1993-11-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this November issue of TASCC is an update of the facility, news of a purchase of phase-shifters and a listing of experiments run in November. 2 figs.

TASCC newsletter volume 7 no. 12

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1993-12-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this December issue of TASCC is an update of the facility, a year end review by the director and a listing of experiments carried out in December. 3 figs.

TASCC newsletter volume 8 no. 7

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1994-07-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this July issue of TASCC is an update of the facility,news on TASCC personnel, results of a coulomb-excitation and a listing of July`s experiments. 4 figs.

MINERALOGICAL AND PARTICULATE MORPHOLOGICAL ...

African Journals Online (AJOL)

Preferred Customer

earth (soils and clays) or soil-like substances such as chalk, by humans (human) and animals. (enzootic) [2-4]. .... of the color of the geophagic clayey soils from Botswana are presented in Table 1. The colors of .... blue to yellow. Trans parent.

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.

TASCC newsletter volume 9 no. 12

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1995-12-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this December issued of TASCC is an update of the facility, a year -end review of TASCC by the director and a listing of December`s experiments. 1 fig.

The olistostroms and cretaceous-Paleocene olistoplakes in sediments of Northern part of Tajik depression

International Nuclear Information System (INIS)

Kukhtikov, M.M.; Vinnichenko, G.P.

1991-01-01

In sediments of Northern part of Tajikistan the great amount of massives without foundation and accumulated blocks without order were found. These sediments are from rock of chalk-Palaeogene period. They belong to olistostrom and olistoplaka category. They are found inside neogenic cut

Petrophysical and rock-mechanics effects of CO2 injection for enhanced oil recovery

DEFF Research Database (Denmark)

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

2014-01-01

this issue we studied two types of chalk from South Arne field, North Sea: (1) Ekofisk Formation having >12% non-carbonate and (2) Tor Formation, which has less than 5% non-carbonate. We performed a series of laboratory experiments to reveal the changes in petrophysical and rock-mechanics properties due...... reservoirs. North Sea chalk is characterized by high porosity but also high specific surface causing low permeability. A high porosity provides room for CO2 storage, while a high specific surface causes a high risk for chemical reaction and consequently for mechanical weakening. In order to address...... to the injection of CO2 at supercritical state. We analyzed these changes with respect to the differences in porosity, specific surface, pore stiffness, wettability, mineralogy and mechanical strength. We observed a 2–3% increase in porosity, a minor decrease of specific surface and consequently a small increase...

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...

Micro-CT in situ study of carbonate rock microstructural evolution for geologic CO2 storage

DEFF Research Database (Denmark)

Zheng, Yi; Yang, Yan; Rogowska, M.

2017-01-01

to achieve this is to find a suitable condition to create a stable 3D space in carbonate rock by injecting liquid to prepare space for the later CO2 injection. Micro-CT imaging is a non-destructive 3D method that can be used to study the property changes of carbonate rocks during and after CO2 injection....... The advance in lab source based micro-CT has made it capable of in situ experiments. We used a commercial bench top micro-CT (Zeiss Versa XRM410) to study the microstructure changes of chalk during liquid injection. Flexible temporal CT resolution is essential in this study because that the time scales...... of coupled physical and chemical processes can be very different. The results validated the feasibility of using a bench top CT system with a pressure cell to monitor the mesoscale multiphase interactions in chalk....

Oil recovery enhancement from fractured, low permeability reservoirs. Annual report 1990--1991, Part 1

Energy Technology Data Exchange (ETDEWEB)

Poston, S.W.

1991-12-31

Joint funding by the Department of Energy and the State of Texas has Permitted a three year, multi-disciplinary investigation to enhance oil recovery from a dual porosity, fractured, low matrix permeability oil reservoir to be initiated. The Austin Chalk producing horizon trending thru the median of Texas has been identified as the candidate for analysis. Ultimate primary recovery of oil from the Austin Chalk is very low because of two major technological problems. The commercial oil producing rate is based on the wellbore encountering a significant number of natural fractures. The prediction of the location and frequency of natural fractures at any particular region in the subsurface is problematical at this time, unless extensive and expensive seismic work is conducted. A major portion of the oil remains in the low permeability matrix blocks after depletion because there are no methods currently available to the industry to mobilize this bypassed oil. The following multi-faceted study is aimed to develop new methods to increase oil and gas recovery from the Austin Chalk producing trend. These methods may involve new geological and geophysical interpretation methods, improved ways to study production decline curves or the application of a new enhanced oil recovery technique. The efforts for the second year may be summarized as one of coalescing the initial concepts developed during the initial phase to more in depth analyses. Accomplishments are predicting natural fractures; relating recovery to well-log signatures; development of the EOR imbibition process; mathematical modeling; and field test.

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.

Inelastic Scattering of Neutrons in Solids and Liquids. V. II. Proceedings of the Symposium on Inelastic Scattering of Neurons in Solids and Liquids

Energy Technology Data Exchange (ETDEWEB)

NONE

1963-01-15

The Chalk River Symposium on Inelastic Scattering of Neutrons in Solids and Liquids was the International Atomic Energy Agency's second symposium held on this subject. The previous one was held in 1960 in Vienna and the very first international meeting in this field took place in 1957 in Stockholm. At the Stockholm meeting only 11 papers from six countries were presented; this was the very beginning of a rapidly developing new branch of physics. At the Vienna Symposium there were 50 papers from 12 countries. At Chalk River 67 papers from 13 countries and three international organizations, the European Atomic Energy Community, the Joint Institute for Nuclear Research and the International Atomic Energy Agency, were presented and discussed. In several other countries, either research in this field has already begun or preparations to start it are under way. This is an indication that the interest in using inelastic scattering of neutrons as a method to study the internal dynamics of solids, liquids and molecules is continuously increasing. On the other hand, a deeper knowledge of the dynamic properties of moderators plays an important role in the understanding of the process of thermalization of neutrons. The latter study is of special importance in promoting advances in nuclear reactor technology. In the light of these developments the International Atomic Energy Agency, with the co-sponsorship of the United Nations Educational, Scientific and Cultural Organization, organized the Symposium at Chalk River from 10 to 14 September 1962 on the generous invitation of the Government of Canada and Atomic Energy of Canada Limited.

Teachers Building Dwelling Thinking with Slideware | Adams | Indo ...

African Journals Online (AJOL)

Teacher-student discourse is increasingly mediated through, by and with information and communication technologies: in-class discussions have found new, textually-rich venues online; chalk and whiteboard lectures are rapidly giving way to PowerPoint presentations. Yet, what does this mean experientially for teachers?

TASCC newsletter volume 6 no. 9

International Nuclear Information System (INIS)

Thomson, L.

1992-09-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this September issue is a report of TASCC productivity, awards from AECL, and a symposium hosted by TASCC, a facility report and operating record and a listing of September's experiments. 1 fig

TASCC newsletter volume 8 no. 4

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1994-04-01

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, news on the Penning-trap spectrometer, educators at CRL, AECB inspection and a listing of April`s experiments. 1 fig.

Technical Evaluation Report 29: Integrated Learning Management Systems

Directory of Open Access Journals (Sweden)

Linda Schwartz

2004-04-01

Full Text Available Four integrated learning management packages were reviewed: CentraOne, IntraLearn, Lyceum, and Silicon Chalk. These products provide different combinations of synchronous and asynchronous tools. The current report examines the products in relation to their specific value for distance educators and students.

The Effect of Meteorological Factors on the Population Dynamics of ...

African Journals Online (AJOL)

Michael Horsfall

Regression equations of fly incidence with all the meteorological parameters were also determined. Results of the present investigation may be utilized in chalking out sustainable pest management strategy in the agro-ecological system under consideration. @ JASEM. Fruit flies are important pests of fruits, vegetables and.

Poroelasticity of high porosity chalk under depletion

DEFF Research Database (Denmark)

Andreassen, Katrine Alling; Fabricius, Ida Lykke

2013-01-01

on mechanical test results is found to be low-er than the pretest dynamic Biot coefficient determined from elastic wave propagation for the loading path and with less deviation under depletion. The calculated lateral stress is lower than the experimentally measured lateral stress depending on loading path...

Late Maastrichtian chalk mounds, Stevns Klint, Denmark

DEFF Research Database (Denmark)

Anderskouv, Kresten; Damholt, Tove; Surlyk, Finn

2007-01-01

that were largely biological and associated with benthic growth and sediment trapping of mainly bryozoans. Examples of end-member conditions are known from Haute Normandy, France and the lower Danian of Stevns Klint. The structures described here adds to the considerable complexity of depositional styles...

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…

TASCC newsletter volume 7 no. 10

International Nuclear Information System (INIS)

Thomson, L.

1993-10-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this October issue of TASCC is an update of the facility report, ECR ion source development, new measurement of Carbon 10, Penning-trap mass spectrometer and a listing of October's experiments. 2 figs

Progress report - Physical and Environmental Sciences - TASCC Division -1995 July 1 to December 31

Energy Technology Data Exchange (ETDEWEB)

Hardy, J C [ed.

1996-05-01

Included in this progress report of the TASCC division at Chalk River Nuclear Laboratories is the research and development being carried out at this time and a listing of the relevant publications, reports, lectures and conference contributions. The TASCC staff is also detailed. 8 tabs.,16 figs.

Pesticide sorption by low organic carbon sediments: A sceening for seven herbicides

DEFF Research Database (Denmark)

Madsen, Lene; Lindhardt, Bo; Rosenberg, Per

2000-01-01

The sorption of seven pesticides in 10 Danish aquifer sediments has been studied. These sediments all have a total organic carbon (TOC) content below 1 g kg(-1), and include carbonate-bearing and carbonate-free Quatenary sand deposits and a Cretaceous chalk aquifer. Batch experiments were carried...

TASCC newsletter volume 8 no. 8

International Nuclear Information System (INIS)

Thomson, L.

1994-08-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this August issue of TASCC is an update of the facility, personnel changes at TASCC, awards to TASCC personnel, workshop on deflectors, beam calculations on PC's and a listing of August's experiments. 2 figs

Fulltext PDF

Indian Academy of Sciences (India)

Biology Department. Homi Bhabha Center for. The technique of chromatography is studied to bring forth the. Science Education (TIFR) underlying concepts such as adsorption, partition, polarity/. Mumbai 400005, India. non-polarity of a compound. The materials required are very simple such as chalk, starch, ink, etc.

Progress report - Physical and Environmental Sciences - TASCC Division -1995 July 1 to December 31

International Nuclear Information System (INIS)

Hardy, J.C.

1996-05-01

Included in this progress report of the TASCC division at Chalk River Nuclear Laboratories is the research and development being carried out at this time and a listing of the relevant publications, reports, lectures and conference contributions. The TASCC staff is also detailed. 8 tabs.,16 figs

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...

The Impact of Virtual Reality Programs in Career and Technical Education

Science.gov (United States)

Catterson, Anna J.

2013-01-01

Instructional technology has evolved from blackboards with chalk to in some cases three-dimensional virtual reality environments in which students are interacting and engaging with other students worldwide. The use of this new instructional methodology, known as "virtual reality," has experienced substantial growth in higher education…

WIMS-CRNL

International Nuclear Information System (INIS)

Phillips, G.J.

1982-08-01

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 library, and the relation of WIMS-CRNL to other versions of the code

Potentiometric surface of the Upper Patapsco aquifer in southern Maryland, September 2009

Science.gov (United States)

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2010-01-01

This report presents a map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 65 wells. The highest measured water level was 118 feet above sea level near the northern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined to the south toward a well field in the Annapolis-Arnold area, and from all directions toward three additional cones of depression. These cones are located in the Waldorf-La Plata area, Chalk Point, and the Leonardtown-Lexington Park area. The lowest measured groundwater levels were 26 feet below sea level at Annapolis, 108 feet below sea level south of Waldorf, 60 feet below sea level at Chalk Point, and 83 feet below sea level at Leonardtown. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Eelgrass fairy rings: sulfide as inhibiting agent

DEFF Research Database (Denmark)

Borum, Jens; Raun, Ane-Marie Løvendahl; Hasler-Sheetal, Harald

2014-01-01

specifically, for the apparent die- off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m−2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots...... expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were...... substantial invasion of sulfide from the sediment. neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic...

An age-calibrated record of upper Campanian – Maastrichtian climate change in the Boreal Realm

DEFF Research Database (Denmark)

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

nannofossil chalk is in agreement with planktic biotic events of the latest Cretaceous and matches well with climatic trends of intermediate- and deep-waters from other oceanic basins recorded through benthic foraminiferal d18O (Barrera and Savin, 1999). However, most planktic foraminiferal d18O data do......The latest Cretaceous climate of the Boreal Realm was recorded through high-resolution bulk carbon- and oxygen-stable isotopes and a nannofossil temperature index (NTI) on the Stevns-1 core (Denmark) which recovered 456 m of upper Campanian to basal Danian chalk with ~100% recovery and an excellent...... temperatures (SSTs) in the Boreal Realm. Three warming events punctuate the overall cooling trend of the latest Cretaceous: (1) the late Campanian climatic optimum (73.9–71.6 Ma) is characterized by maximum SSTs of 20°C, (2) the mid-Maastrichtian warming (69.7–68 Ma) is characterized by stable SSTs around 17°C...

Experience with remediating radiostrontium-contaminated ground water and surface water with versions of AECL's CHEMIC process

International Nuclear Information System (INIS)

Vijayan, S.

2006-01-01

Numerous approaches have been developed for the remediation of radiostrontium ( 90 Sr) contaminated ground water and surface water. Several strontium-removal technologies have been assessed and applied at AECL's (Atomic Energy of Canada Limited) Chalk River Laboratories. These include simple ion exchange (based on non-selective natural zeolites or selective synthetic inorganic media), and precipitation and filtration with or without ion exchange as a final polishing step. AECL's CHEMIC process is based on precipitation-microfiltration and ion-exchange steps. This paper presents data related to radiostrontium removal performance and other operational experiences including troubleshooting with two round-the-clock, pilot-scale water remediation plants based on AECL's CHEMIC process at the Chalk River Laboratories site. These plants began operation in the early 1990s. Through optimization of process chemistry and operation, high values for system capability and system availability factors, and low concentrations of 90 Sr in the discharge water approaching drinking water standard can be achieved. (author)

Tree Coring as a Complement to Soil Gas Screening to Locate PCE and TCE Source Zones and Hot Spots

DEFF Research Database (Denmark)

Nielsen, Mette Algreen; Trapp, Stefan; Rehne Jensen, Pernille

2015-01-01

) or trichloroethylene (TCE) to evaluate their ability to locate source zones and contaminant hot spots. One test site represented a relatively homogeneous sandy soil and aquifer, and the second a more heterogeneous geology with both sandy and less permeable clay till layers overlying a chalk aquifer. Tree cores from...

TASCC newsletter volume 7 no. 7

International Nuclear Information System (INIS)

Thomson, L.

1993-07-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this July issue information is gained on solar cells as fission detectors, database conversion to VISTA, a facility report on beam production, employment equity at TASCC and insight into the cyclotron electrostatic deflector behaviour. 3 figs

TASCC newsletter volume 5 no. 10

International Nuclear Information System (INIS)

Thomson, L.

1991-10-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this October issue is a report on the commissioning of the cyclotron, a new AMS test method for Chlorine 36 beam, a facility report and operating record and a listing of experiments conducted in October

TASCC newsletter volume 7 no. 10

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1993-10-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this October issue of TASCC is an update of the facility report, ECR ion source development, new measurement of Carbon 10, Penning-trap mass spectrometer and a listing of October`s experiments. 2 figs.

TASCC newsletter volume 7 no. 4

International Nuclear Information System (INIS)

Thomson, L.

1993-04-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in the April issue is information on damage tests of satellite instrumentation, general news on success of beams achieved, assessment by NPPAP panel on TASCC programs, staff changes and a listing of April's experiments. 2 figs

Vietnam seeks optimal size for emerging businesses | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

2016-04-20

Apr 20, 2016 ... Languages ... Some observers chalk up the difficulties to foreign companies' lack of ... Learn about the GEM report launch and remarks by the Canadian ... An IDRC-funded project in Asia found that distance education can be ... Tourism is an important driver of economic growth throughout Southeast Asia.

TASCC newsletter volume 8 no. 6

International Nuclear Information System (INIS)

Thomson, L.

1994-06-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue of TASCC is an update of the facility, a review of federal strategy for science and technology, construction on the Canadian Penning Trap Mass Spectrometer and a listing of June's experiments. 1 fig

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.

CLIFF COLLAPSE HAZARD FROM REPEATED MULTICOPTER UAV ACQUISITIONS: RETURN ON EXPERIENCE

Directory of Open Access Journals (Sweden)

T. J. B. Dewez

2016-06-01

Full Text Available Cliff collapse poses a serious hazard to infrastructure and passers-by. Obtaining information such as magnitude-frequency relationship for a specific site is of great help to adapt appropriate mitigation measures. While it is possible to monitor hundreds-of-meter-long cliff sites with ground based techniques (e.g. lidar or photogrammetry, it is both time consuming and scientifically limiting to focus on short cliff sections. In the project SUAVE, we sought to investigate whether an octocopter UAV photogrammetric survey would perform sufficiently well in order to repeatedly survey cliff face geometry and derive rock fall inventories amenable to probabilistic rock fall hazard computation. An experiment was therefore run on a well-studied site of the chalk coast of Normandy, in Mesnil Val, along the English Channel (Northern France. Two campaigns were organized in January and June 2015 which surveyed about 60 ha of coastline, including the 80-m-high cliff face, the chalk platform at its foot, and the hinterland in a matter of 4 hours from start to finish. To conform with UAV regulations, the flight was flown in 3 legs for a total of about 30 minutes in the air. A total of 868 and 1106 photos were respectively shot with a Sony NEX 7 with fixed focal 16mm. Three lines of sight were combined: horizontal shots for cliff face imaging, 45°-oblique views to tie plateau/platform photos with cliff face images, and regular vertical shots. Photogrammetrically derived dense point clouds were produced with Agisoft Photoscan at ultra-high density (median density is 1 point every 1.7cm. Point cloud density proved a critical parameter to reproduce faithfully the chalk face’s geometry. Tuning down the density parameter to “high” or “medium”, though efficient from a computational point of view, generated artefacts along chalk bed edges (i.e. smoothing the sharp gradient and ultimately creating ghost volumes when computing cloud to cloud differences. Yet

Composite Gypsum Binders with Silica-containing Additives

Science.gov (United States)

Chernysheva, N. V.; Lesovik, V. S.; Drebezgova, M. Yu; Shatalova, S. V.; Alaskhanov, A. H.

2018-03-01

New types of fine mineral additives are proposed for designing water-resistant Composite Gypsum Binders (CGB); these additives significantly differ from traditional quartz feed: wastes from wet magnetic separation of Banded Iron Formation (BIF WMS waste), nanodispersed silica powder (NSP), chalk. Possibility of their combined use has been studied as well.

Techniques of Teaching Arabic as a Foreign Language through Constructivist Paradigm: Malaysian Perspective

Science.gov (United States)

Faryadi, Qais

2007-01-01

This analysis discusses the constructivist paradigm of teaching Arabic as a foreign language in Malaysian settings. This review examines the role of interactive multimedia in enhancing the chalk and talk methods of teaching Arabic in Malaysian schools. This paper also investigates the importance of Arabic Language in Malaysia. Furthermore, the…

TASCC newsletter volume 8 no. 5

International Nuclear Information System (INIS)

Thomson, L.

1994-05-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this May issue of TASCC is an update of the facility, a visit by the Nuclear Physics Technical Review Committee, sizing of meteors, Deep River Science Academy on TASCC projects and a listing of May's experiments. 2 figs

TASCC newsletter volume 8 no. 9

International Nuclear Information System (INIS)

Thomson, L.

1994-09-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this September issue of TASCC is an update of the facility, winner of Nobel prize, dating of fossil seeds using Chlorine 36, promotion of TASCC at a local fair and a listing of September's experiments. 1 fig

TASCC newsletter volume 7 no. 4

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1993-04-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in the April issue is information on damage tests of satellite instrumentation, general news on success of beams achieved, assessment by NPPAP panel on TASCC programs, staff changes and a listing of April`s experiments. 2 figs.

Teaching Economics to the Best Undergraduates: What Are the Problems?

Science.gov (United States)

Andreopoulos, Giuliana Campanelli; Panayides, Alexandros

2009-01-01

Economics is usually perceived as a difficult subject among undergraduate students with negative repercussions on their performance. The literature suggests that the students' problems with principles of economics are mainly related to the style and method of teaching together with the course content. Particularly attacked are the chalk and talk…

De Centauriebremraap (Orobanche elatior Sutton) in Zuid-Limburg: een nieuwe soort voor de Nederlandse flora

NARCIS (Netherlands)

Kreutz, C.A.J.

1989-01-01

From 1973 onwards an Orobanche species was found repeatedly (though at intervals of several years) on a chalk slope in the South of Limburg. At first the plant was identified as O. lutea, but the author argues that in fact it is O. elatior. Presumably its host is Centaurea scabiosa.

E-Learning Systems Requirements Elicitation: Perspectives and Considerations

Science.gov (United States)

AlKhuder, Shaikha B.; AlAli, Fatma H.

2017-01-01

Training and education have evolved far beyond black boards and chalk boxes. The environment of knowledge exchange requires more than simple materials and assessments. This article is an attempt of parsing through the different aspects of e-learning, understanding the real needs, and conducting the right requirements to build the appropriate…

TASCC newsletter volume 8 no. 6

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1994-06-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue of TASCC is an update of the facility, a review of federal strategy for science and technology, construction on the Canadian Penning Trap Mass Spectrometer and a listing of June`s experiments. 1 fig.

TASCC newsletter volume 8 no. 8

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1994-08-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this August issue of TASCC is an update of the facility, personnel changes at TASCC, awards to TASCC personnel, workshop on deflectors, beam calculations on PC`s and a listing of August`s experiments. 2 figs.

TASCC newsletter volume 7 no. 8

International Nuclear Information System (INIS)

Thomson, L.

1993-08-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this August issue is information on the status of the TRC's written report, visitors to TASCC, the facility report and new intruder bands that were discovered, as well as a listing of August 's experiments. 2 figs

TASCC newsletter volume 9 no. 7

International Nuclear Information System (INIS)

Thomson, L.

1995-07-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this July issue of TASCC is an update of the facility, submission of report by the Program Advisory Committee, government program review begins at AECL, awards to TASCC personnel and a listing of July's experiments. 2 figs

Essentials for the Teacher's Toolbox

Science.gov (United States)

Uhler, Jennifer

2012-01-01

Every profession has a set of essential tools for carrying out its work. Airplane mechanics cannot repair engines without sophisticated diagnostics, wrenches, and pliers. Surgeons cannot operate without scalpels and clamps. In contrast, teaching has often been perceived as a profession requiring only students, chalk, and a blackboard in order for…

Thinking Images: Doing Philosophy in Film and Video

Science.gov (United States)

Parkes, Graham

2009-01-01

Over the past several decades film and video have been steadily infiltrating the philosophy curriculum at colleges and universities. Traditionally, teachers of philosophy have not made much use of "audiovisual aids" in the classroom beyond the chalk board or overhead projector, with only the more adventurous playing audiotapes, for example, or…

TASCC newsletter volume 7 no. 6

International Nuclear Information System (INIS)

Thomson, L.

1993-06-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this June issue of TASCC is a facility report, updates on experiments being conducted, educational affiliation with the Deep River Science Academy and findings involving gadolinium-149 and information on a highly deformed band found in praseodymium. 2 figs

TASCC newsletter volume 8 no. 3

International Nuclear Information System (INIS)

Thomson, L.

1994-03-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this March issue of TASCC is an update of the facility, a VAX station installation on 8π spectrometer, staff awards, time-of-flight techniques for AMS of iodine isotopes and a listing of experiments for March. 4 figs

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...

Does Student Quality Matter in the Teaching of Economic Principles?

Science.gov (United States)

Andreopoulos, Giuliana Campanelli; Panayides, Alexandros

2010-01-01

Economics is usually perceived as a difficult subject among undergraduate students and the literature suggests that the student's problems with principles of economics are mainly related to the chalk and talk type of teaching, the simplicity of economic models, limited discussions on current economic issues, and on race, gender, and other types of…

Evaluating Twitter and Its Impact on Student Learning in Principles of Economics Courses

Science.gov (United States)

Al-Bahrani, Abdullah; Patel, Darshak; Sheridan, Brandon J.

2017-01-01

Ever since Becker and Watts (1996) found that economic educators rely heavily on "chalk and talk" as a primary teaching method, economic educators have been seeking new ways to engage students and improve learning outcomes. Recently, the use of social media as a pedagogical tool in economics has received increasing interest. The authors…

21st International Conference on DNA Computing and Molecular Programming

Science.gov (United States)

2016-05-24

M, Nand K. More specifically, a solution CRN Cis represented through the valuation of r and p , which are extracted from the model returned by Z3...aldonado, Eric Martinez , Robert T. Schweller, and Tim Wylie University of Texas Rio Grande Valley , Edinburg, TX 78539-2999, USA {camer on . chalk01 , b

A Lesson on Evolution & Natural Selection

Science.gov (United States)

Curtis, Anthony D.

2010-01-01

I describe three activities that allow students to explore the ideas of evolution, natural selection, extinction, mass extinction, and rates of evolutionary change by engaging a simple model using paper, pens, chalk, and a chalkboard. As a culminating activity that supports expository writing in the sciences, the students write an essay on mass…

TASCC newsletter volume 8 no. 5

Energy Technology Data Exchange (ETDEWEB)

Thomson, L

1994-05-01

A newsletter produced by Chalk River`s Tandem Accelerator Superconducting Cyclotron Facility. Included in this May issue of TASCC is an update of the facility, a visit by the Nuclear Physics Technical Review Committee, sizing of meteors, Deep River Science Academy on TASCC projects and a listing of May`s experiments. 2 figs.

TASCC newsletter volume 9 no. 2

International Nuclear Information System (INIS)

Thomson, L.

1995-02-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this February issue of TASCC is an update of the facility, beams to simulate the cosmic-ray environment in space, personnel changes at TASCC, modular approach to rebuilding cyclotron rf control electronics and a listing of February's experiments. 1 fig

TASCC newsletter volume 9 no. 3

International Nuclear Information System (INIS)

Thomson, L.

1995-03-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this March issue of TASCC is an update of the facility, the new Program Advisory Committee, a memo of understanding signed with the Centre Recherche Nucleaires, a demonstration of graphical analysis software and a listing of March's experiments. 1 fig

Original Research First aid practices, beliefs, and sources of ...

African Journals Online (AJOL)

hypothermia especially in children.5 Use of aloe vera has also been shown to be associated with significantly delayed wound healing and use of oils, vaseline, fats, flour, powdered chalk and creams which was believed to form effective air barrier was not beneficial and made secondary treatment by the doctor/surgeon ...

Lithostratigraphy of the Palaeogene - Lower Neogene succession of the Danish North Sea

DEFF Research Database (Denmark)

Schiøler, Poul-Henrik; Andsbjerg, Jan; Clausen, Ole Rønø

2007-01-01

sediments of the Danish sector of the North Sea is revised. The sediment package from the top of the Chalk Group to the base of the Nordland Group is subdivided into seven formations containing eleven new members. The existing Våle, Lista, Sele, Fur, Balder, Horda and Lark Formations of previously...

Powerpoint Presentation in Learning Physiology by Undergraduates with Different Learning Styles

Science.gov (United States)

Ankad, Roopa B.; Shashikala, G. V.; Herur, Anita; Manjula, R.; Chinagudi, Surekharani; Patil, Shailaja

2015-01-01

PowerPoint presentations (PPTs) have become routine in medical colleges because of their flexible and varied presentation capabilities. Research indicates that students prefer PPTs over the chalk-and-talk method, and there is a lot of debate over advantages and disadvantages of PPTs. However, there is no clear evidence that PPTs improve student…

An integrated subsurface analysis of clastic remobilization and injection

DEFF Research Database (Denmark)

Andresen, Katrine Juul; Clausen, O.R.

2014-01-01

extending from the top of the Paleocene Lista Formation to the base of the injectites indicate that the source sand was located within the Lista Formation; possibly deposited in a distinct valley cut into the top of the Chalk Group. The geometry of the observed injectites ranges from a basal sill with wings...

Facing the challenges of the Eu emissions trading scheme

International Nuclear Information System (INIS)

Bryers, S.

2006-01-01

Carbon Capital Markets, a specialist trader in the EU ETS has helped a number of cement and chalk producers in Europe manage their CO 2 (or EU Allowance (EUA)) position. From its experience with working with these companies, it recommends ways in which manufacturers can manage their CO 2 position more effectively. (author)

P.A. Mbenzi and D.N. Iithete. English-Oshindonga Dictionary for Pri-

African Journals Online (AJOL)

The front matter of the dictionary consists of a preface and three paragraphs on how to use ... understanding of other subjects such as History, Science, Geography, etc." An .... mar description, assist the user in providing clues as to the existing differences ... "He uses chalk to write on the blackboard", while the accompanying.

Paleoenvironments of the Jurassic and Cretaceous Oceans: Selected Highlights

Science.gov (United States)

Ogg, J. G.

2007-12-01

There are many themes contributing to the sedimentation history of the Mesozoic oceans. This overview briefly examines the roles of the carbonate compensation depth (CCD) and the associated levels of atmospheric carbon dioxide, of the evolution of marine calcareous microplankton, of major transgressive and regressive trends, and of super-plume eruptions. Initiation of Atlantic seafloor spreading in the Middle Jurassic coincided with an elevated carbonate compensation depth (CCD) in the Pacific-Tethys mega-ocean. Organic-rich sediments that would become the oil wealth of regions from Saudi Arabia to the North Sea were deposited during a continued rise in CCD during the Oxfordian-early Kimmeridgian, which suggests a possible increase in carbon dioxide release by oceanic volcanic activity. Deep-sea deposits in near-equatorial settings are dominated by siliceous shales or cherts, which reflect the productivity of siliceous microfossils in the tropical surface waters. The end-Jurassic explosion in productivity by calcareous microplankton contributed to the lowering of the CCD and onset of the chalk ("creta") deposits that characterize the Tithonian and lower Cretaceous in all ocean basins. During the mid-Cretaceous, the eruption of enormous Pacific igneous provinces (Ontong Java Plateau and coeval edifices) increased carbon dioxide levels. The resulting rise in CCD terminated chalk deposition in the deep sea. The excess carbon was progressively removed in widespread black-shale deposits in the Atlantic basins and other regions - another major episode of oil source rock. A major long-term transgression during middle and late Cretaceous was accompanied by extensive chalk deposition on continental shelves and seaways while the oceanic CCD remained elevated. Pacific guyots document major oscillations (sequences) of global sea level superimposed on this broad highstand. The Cretaceous closed with a progressive sea-level regression and lowering of the CCD that again enabled

Modification of asphaltic concrete with a mineral polymeric additive based on butadiene-styrene rubber and chemically precipitated calcium carbonate

Directory of Open Access Journals (Sweden)

S. I. Niftaliev

2016-01-01

Full Text Available Modification of asphaltic concrete with a mineral polymeric additive based on butadiene – styrene rubber and chemically precipitated calcium carbonate. This paper presents the results of the study of physical – mechanical and service properties of the asphaltic concrete modified with the mineral polymeric composition. Calcium carbonate is used both as a filler and a coagulant. The chalk was preliminarily ground and hydrophobizated by stearic acid. These operations contribute to even distribution of the filler and interfere with lump coagulation. As a result of the experiments, it was found that the best results were obtained by combining the operations of dispersion and hydrophobization. The optimal amount of stearic acid providing the finest grinding in a ball mill is a content from 3 to 5% by weight. The optimal grinding time of the filler was found (4–6 hours. With increasing dispersion time the particles form agglomerates. Filling the butadiene styrene latex with the hydrophobic fine-grained calcium carbonate was carried out in the laboratory mixer. As a result of the experimental works, it was found that the best distribution of the filler takes place with ratio of rubber: chalk – 100:400. The resulting modifier was subjected to the thermal analysis on the derivatograph to determine its application temperature interval. A marked reduction in weight of the mineral polymeric modifier begins at 350 °C. Thus, high temperature of the modifier destruction allows to use it at the temperature of the technological process of asphaltic concrete preparation (up to 170 °C. It was found that an increase in the amount of the carbonate filler in the rubber SKS 30АRК significantly increases its thermal resistance and connection of the polymer with the chalk in the composition.

Gender preference between traditional and PowerPoint methods of teaching gross anatomy.

Science.gov (United States)

Nuhu, Saleh; Adamu, Lawan Hassan; Buba, Mohammed Alhaji; Garba, Sani Hyedima; Dalori, Babagana Mohammed; Yusuf, Ashiru Hassan

2018-01-01

Teaching and learning process is increasingly metamorphosing from the traditional chalk and talk to the modern dynamism in the information and communication technology. Medical education is no exception to this dynamism more especially in the teaching of gross anatomy, which serves as one of the bases of understanding the human structure. This study was conducted to determine the gender preference of preclinical medical students on the use of traditional (chalk and talk) and PowerPoint presentation in the teaching of gross anatomy. This was cross-sectional and prospective study, which was conducted among preclinical medical students in the University of Maiduguri, Nigeria. Using simple random techniques, a questionnaire was circulated among 280 medical students, where 247 students filled the questionnaire appropriately. The data obtained was analyzed using SPSS version 20 (IBM Corporation, Armonk, NY, USA) to find the method preferred by the students among other things. Majority of the preclinical medical students in the University of Maiduguri preferred PowerPoint method in the teaching of gross anatomy over the conventional methods. The Cronbach alpha value of 0.76 was obtained which is an acceptable level of internal consistency. A statistically significant association was found between gender and preferred method of lecture delivery on the clarity of lecture content where females prefer the conventional method of lecture delivery whereas males prefer the PowerPoint method, On the reproducibility of text and diagram, females prefer PowerPoint method of teaching gross anatomy while males prefer the conventional method of teaching gross anatomy. There are gender preferences with regard to clarity of lecture contents and reproducibility of text and diagram. It was also revealed from this study that majority of the preclinical medical students in the University of Maiduguri prefer PowerPoint presentation over the traditional chalk and talk method in most of the

Learning through Equity Trading Simulation

Science.gov (United States)

Moffit, Timothy; Stull, Charles; McKinney, Hannah

2010-01-01

Over the past several decades, colleges and universities have moved away from the traditional chalk-and-talk lecture. Professors have experimented with a myriad of methods to engage students more fully. Some of the innovations that have been used have succeeded in improving student performance and satisfaction. In this paper we report the learning…

Sparking Old and New Ideas

Science.gov (United States)

Williams-Rossi, Dara; Campbell, Laurie O.

2012-01-01

In the past, teachers have used chalkboards for "chalk talks," a strategy where a teacher wrote words and drew images to demonstrate reflecting, document generating ideas, and explore knowledge. Out with the old-school version and in with the "Marker Sparker" method, which uses whiteboards or poster paper and colorful markers to achieve the same…

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.

Back to the Drawing Board Reconstructing DaVinci's Vitruvian Man to Teach Anatomy

Science.gov (United States)

Babaian, C.

2009-01-01

In today's high tech world, one hardly expects to see the original chalkboard or blackboard utilized in research, teaching, or scientific communication, but having spent an equal number of years doing both art and biology and dabbling in computer graphics, the author has found the simple technology of the chalkboard and chalk to have incredible…

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...

Potentiometric Surface of the Upper Patapsco Aquifer in Southern Maryland, September 2007

Science.gov (United States)

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2009-01-01

This report presents a map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2007. The map is based on water-level measurements in 50 wells. The highest measured water level was 120 feet above sea level near the northern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined to the south toward a well field in the Annapolis-Arnold area, and from all directions toward four cones of depression. These cones are located in the Waldorf-La Plata area, Chalk Point-Prince Frederick area, Swan Point subdivision in southern Charles County, and the Lexington Park-St. Inigoes area. The lowest measured ground-water level was 44 feet below sea level at Arnold, 106 feet below sea level south of Waldorf, 54 feet below sea level at Swan Point, 59 feet below sea level at Chalk Point, and 58 feet below sea level at Lexington Park.

Diffusion in porous structures containing three fluid phases

International Nuclear Information System (INIS)

Galani, A.N.; Kainourgiakis, M.E.; Stubos, A.K.; Kikkinides, E.S.

2005-01-01

In the present study, the tracer diffusion in porous media filled by three fluid phases (a non-wetting, an intermediate wetting and a wetting phase) is investigated. The disordered porous structure of porous systems like random sphere packing and the North Sea chalk, is represented by three-dimensional binary images. The random sphere pack is generated by a standard ballistic deposition procedure, while the chalk matrix by a stochastic reconstruction technique. Physically sound spatial distributions of the three phases filling the pore space are determined by the use of a simulated annealing algorithm, where those phases are initially randomly distributed in the pore space and trial-and-error swaps are performed in order to attain the global minimum of the total interfacial energy. The acceptance rule for a trial move during the annealing is modified properly improving the efficiency of the technique. The diffusivities of the resulting domains are computed by a random walk method. A parametric study with respect to the pore volume fraction occupied by each fluid phase and the ratio of the diffusivities in the fluid phases is performed. (authors)

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...

Safe and secure: transportation of radioactive materials

International Nuclear Information System (INIS)

Howe, D.

2015-01-01

Western Waste Management Facility is Central Transportation Facility for Low and Intermediate waste materials. Transportation support for Stations: Reactor inspection tools and heavy water between stations and reactor components and single bundles of irradiated fuel to AECL-Chalk River for examination. Safety Track Record: 3.2 million kilometres safely travelled and no transportation accident - resulting in a radioactive release.

Calm, Cool, and Comfortable in Clay

Science.gov (United States)

Stylianou, Xanthippi Cynthia

2010-01-01

The author's fourth-grade students had just finished a drawing unit that focused on the human figure. Projects included charcoal gesture drawings and chalk manikin drawings in chiaroscuro. She wanted to integrate a new medium for students to continue their study of the human figure. Since students are always excited to work with clay, making clay…

Detection of defects in logs using computer assisted tomography (CAT) scanning

International Nuclear Information System (INIS)

Tonner, P.D.; Lupton, L.R.

1985-01-01

The Chalk River Nuclear Laboratories of AECL have performed a preliminary feasibility study on the applicability of computer assisted tomographic techniques to detect the internal structure of logs. Cross sections of three logs have been obtained using a medical CAT scanner. The results show that knots, rot and growth rings are easily recognized in both dry and wet logs

two genera of myrtaceae

Indian Academy of Sciences (India)

The present paper deals with the sclereids of three species of Syzygium, S. cumini, Linn. Skeels., S. nodosum. Miq., and S. cinereum Wall, and in Eucalyptus tereticornis Sm. Austral. Metcalfe and Chalk (1950) have already drawn attention to the occurrence of stone-cells in the pith and cortex of the stems of some species of ...

Commissioning of the RFQ1 injector

International Nuclear Information System (INIS)

Arbique, G.M.; Sheikh, J.Y.; Taylor, T.; Birney, L.F.; Davidson, A.D.; Wills, J.S.C.

1987-01-01

The RFQ1 accelerator is being developed at Chalk River to test the limits of the cw RFQ technology. A 50 kV injector has been built and is now being commissioned as the first phase of the program. This paper describes some of the innovative features of the RFQ1 injector and reports on initial operating experience

TASCC newsletter volume 9 no. 1

International Nuclear Information System (INIS)

Thomson, L.

1995-01-01

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, news on distribution of Nuclear Physics News International, installation of the Penning trap mass spectrometer, workshop to be held in June on nuclear physics research, and a listing of January's experiments. 1 fig

Radiation chemistry in the nuclear power reactor environment: from laboratory study to practical application

International Nuclear Information System (INIS)

Stuart, C.R.

1999-01-01

This paper discusses the work carried out at the Chalk River Nuclear Laboratories in underlying and applied radiation chemical research performed to optimise the processes occurring in the four aqueous systems in and around the core. The aqueous systems subject to radiolysis in CANDU reactors are Heat Transport System, Moderator, Liquid Zone Controls and End Shields.

Teaching Design in the First Years of a Traditional Mechanical Engineering Degree: Methods, Issues and Future Perspectives

Science.gov (United States)

Silva, Arlindo; Fontul, Mihail; Henriques, Elsa

2015-01-01

Engineering design is known as an answer to an ill-defined problem. As any answer to an ill-defined problem, it can never be completely right or absolutely wrong. The methods that universities use to teach engineering design, as a consequence of this, suffer from the same fate. However, the accumulated experience with the "chalk and…

Sarsen Stones of Stonehenge: How and by what route were the stones transported? What is the significance of their markings?

Science.gov (United States)

Hill, P A

1961-04-21

A route via Lockeridge and the Avon Valley, involving a slide down the chalk escarpment, is postulated for the sarsen stones of Stonehenge. The transportation problem would have been greatly simplified if the stones had been relayed from point to point over snow or slush during successive winters. Markings on the stones hitherto undescribed are interpreted.

78 FR 26023 - Combined Notice of Filings #1

Science.gov (United States)

2013-05-03

... Chalk Point, LLC, GenOn Delta, LLC, GenOn Energy Management, LLC, GenOn Florida, LP, GenOn Kendall, LLC...: PJM Interconnection, L.L.C. Description: Original Service Agreement No. 3519; Queue No. X4-046 to be...: PJM Interconnection, L.L.C. Description: Original Service Agreement No. 3524; Queue No. X3-066 to be...

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

Development and performance of charged particle detectors applied to the study of heavy ion reactions; Developpement et performances de detecteurs de particules chargees appliques a l`etude des reactions avec ions lourds

Energy Technology Data Exchange (ETDEWEB)

Gourde, M; Beaulieu, L; Dore, D; Laforest, R; Pouliot, J; Roy, R; St-Pierre, C [Laval Univ., Quebec City, PQ (Canada). Dept. de Physique

1994-12-31

The new type of charged particle detector described comprises a thin layer of plastic scintillator over a much thicker CsI(Tl) crystal, an optical guide, and a photomultiplier. Results obtained at Chalk River Laboratories for the identification of particles with Z = 1-6 from the {sup 12}C + {sup 197}Au reaction are shown. 12 refs., 4 figs.

Elastic and electric properties of North Sea Chalk

DEFF Research Database (Denmark)

Olsen, Casper

bjergartsfysiske modeller til forudsigelse af Biot’s koefficient ud fra porøsitet og én lydhastighed og hans resultater tyder på at Berryman’s udbredte ”Selfconsistent Model” er mindre velegnet til det formål, mens at de simplere Isoframe og Bound-averaging metoder giver bedre resultater. Dvorkin’s partikel...

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

The leaching of radioactivity from highly radioactive glass blocks buried below the water table: fifteen years of results

International Nuclear Information System (INIS)

Merritt, W.F.

1976-03-01

The results from two test burials of high-level fission products incorporated into nepheline syenite glass indicate that the nuclear wastes from fuel processing for a 30,000 MWe nuclear power industry could be incorporated into such glass and stored beneath the water table in the waste management area of Chalk River Nuclear Laboratories (CRNL) without harm to the environment. (author)

A recommended program of tritium monitoring research and development

International Nuclear Information System (INIS)

Nickerson, S.B.; Gerdingh, R.F.; Penfold, K.

1982-10-01

This report presents recommendations for programs of research and development in tritium monitoring instrumentation. These recommendations, if implemented, will offer Canadian industry the opportunity to develop marketable instruments. The major recommendations are to assist in the development and promotion of two Chalk River Nuclear Laboratories' monitors and an Ontario Hydro monitor, and to support research and development of a surface monitor

Coincidence of needs in radiological and toxicological protection

International Nuclear Information System (INIS)

Osborne, R.V.

1988-01-01

Research needs for radiological protection and research programs that have evolved to meet these needs parallel closely those in the chemical toxicology field. The similarity of these needs is described as perceived from the radiological side. Further, the frame work for radiologically-related research, out lines of the research programs, and the development of the facilities at Chalk River Nuclear Labs were presented

AECL research programs in life sciences

International Nuclear Information System (INIS)

Marko, A.M.

1981-04-01

The present report summarizes the current research activities in life sciences in the Atomic Energy of Canada Limited-Research Company. The research is carried out at its two main research sites: the Chalk River Nuclear Laboratories and the Whiteshell Nuclear Research Establishment. The summaries cover the following areas of research: radiation biology, medical biophysics, epidemiology, environmental research and dosimetry. (author)

Progress report: Physics Division, 1982 April 1 - June 30

International Nuclear Information System (INIS)

1982-08-01

Nuclear physics studies that took place at Chalk River Nuclear Laboratories during the second quarter of 1982 are described, as well as work in solid state and theoretical physics. The MP Tandem accelerator was shut down to prepare for the installation of a superconducting cyclotron. Computer codes developed during the period and the operation of the computer facilities are described

Validation of Brain Event-Related Potentials as Indicators of Cognitive Styles, Abilities, and Aptitudes.

Science.gov (United States)

1983-02-01

1970; Callaway, 1973, 1975; Chalke & Ertl, 1965; Ertl, 1969; Ertl & Schafer, 1969; Galbraith, Gliddon, & Busk , 1970; Gucker, 1973; Marcus, 1970...related to intelligence--although not always (Bigum, Dustman, & Beck, 1970; Galbraith, Gliddon, & Busk , 1970; Perry, McCoy, Cunningham, Falgout...be directly related to intelligence--but not always (Bigum, Dustman, & Beck, 1970; Galbraith, Gliddon, & Busk , 1970; Perry, McCoy, Cunningham, Falgot

Cw RFQ development

International Nuclear Information System (INIS)

Schriber, S.O.

1985-01-01

A review of research and development related to fabricating and operating radio-frequency quadrupole (RFQ) structures at 100% duty cycle [continuous wave (cw)] is presented, with emphasis on work at the Los Alamos National Laboratory, the Chalk River Nuclear Laboratories, and the University of Frankfurt. Activities in other areas that have an impact on operating cw RFQ systems will be highlighted. 27 refs

Change of MMP dependent on temperature

DEFF Research Database (Denmark)

Rudyk, Svetlana Nikolayevna; Søgaard, Erik Gydesen; Akwansa, Eugene

2008-01-01

   The experiment was conducted with the purpose to investigate how Minimum Miscibility Pressure (MMP) changes at different temperatures. MMP was measured in a high pressure unit. An original oil saturated chalk core plug from the Danish oil field in North Sea was under investigation. The plug...... underestimation of MMP values which can lead to the loss of efficiency of oil extraction....

Progress report chemistry and materials division 1984 January 1 - June 30

International Nuclear Information System (INIS)

1984-08-01

During the first half of 1984 work in the Chemistry and Materials Division of Chalk River Nuclear Laboratories concentrated on studies of ion penetration phenomena, surface phenomena, radiation damage, radiochemical analysis, recycle fuel analysis, gamma spectrometry, mass spectrometry of fuels and moderators, analysis of hydrogen in zirconium alloys, burnup analysis, radiolysis, hydrogen isotope separation, hydrogen adsorption, zirconium corrosion, and metal physics studies of zirconium

SLOWPOKE

International Nuclear Information System (INIS)

Law, Charles.

1979-01-01

The SLOWPOKE (Safe Low Power Critical Experiment) reactor was developed by AECL at Whiteshell and Chalk River between 1968 and 1970. It is a neutron-producing reactor of low power with minimal fuel, shielding, and cooling requirements and intrinsic safety. Four Canadian universities and one German one have acquired SLOWPOKE reactors for neutron activation analyses and for student research in nuclear engineering and reactor physics. (LL)

The MAPLE-X concept dedicated to the production of radio-isotopes

International Nuclear Information System (INIS)

Heeds, W.

1985-06-01

MAPLE is a versatile new Canadian multi-purpose research reactor concept that meets the nuclear aspirations of developing countries. It is planned to convert the NRX reactor at Chalk River Nuclear Laboratories into MAPLE-X as a demonstration prototype of this concept and thereafter to dedicate its operation to the production of radio-isotopes. A description of MAPLE-X and details of molybdenum-99 production are given

Progress report: Physics Division, 1982 January 1 to March 1

International Nuclear Information System (INIS)

1982-05-01

The work of the Physics Division at Chalk River Nuclear Laboratories during the quarter is presented. Areas of interest include nuclear physics, neutron sources, the development of a superconducting cyclotron, high current proton accelerators and electron accelerators, diffraction studies and other solid state physics work in organic and inorganic substances, and computer codes. The operation of the MP tandem accelerator and the computer facilities is reviewed

The African Peace and Security Architecture: Myth or Reality

Science.gov (United States)

2013-03-01

Economic Community of West African States (ECOWAS).15 That notwithstanding, the OAU chalked some successes in conflict management . These included the...mechanism had a Conflict Management Center, which was responsible to the OAU Secretary General for the execution of strategies to prevent, manage...of fourteen intergovernmental organizations in Africa that seek to provide some form of security and conflict management mechanisms. Out of the 54

Progress report, October 1 to December 31, 1959. Physics Division

International Nuclear Information System (INIS)

1959-01-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from October 1, to December 31, 1959. It describes the research in nuclear physics, general physics, theoretical physics and electronics. The research areas covered in this report include nuclear structure, the tandem accelerator, particle detector development, developments in electronics, neutron decay, beta ray spectrometer, fission studies, electronics development and neutron transport theory.

A light-water detritiation project at Chalk River Laboratories

International Nuclear Information System (INIS)

Boniface, H.A.; Castillo, I.; Everatt, A.E.; Ryland, D.K.

2010-01-01

The NRU reactor rod bays is a large, open pool of water that receives hundreds of fuel rods annually, each carrying a small amount of residual tritiated heavy water. The tritium concentration of the rod bays water has risen over the years, to a level that is of concern to the operations staff and to the environment. The proposed long-term solution is to reduce the rod bays tritium concentration by direct detritiation of the water. The Combined Electrolytic-Catalytic Exchange (CECE) process is well suited to the light-water detritiation problem. With a tritium-protium separation factor greater than five, a CECE detritiation process can easily achieve the eight orders of magnitude separation required to split a tritiated light-water feed into an essentially tritium-free effluent stream and a tritiated heavy water product suitable for recycling through a heavy water upgrader. This paper describes a CECE light-water detritiation process specifically designed to reduce the tritium concentration in the NRU rod bays to an acceptable level. The conceptual design of a 600 Mg/a detritiation process has been developed and is now at the stage of project review and the beginning of detailed design. (author)

Rock physical aspects of CO2 injection in chalk

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul

Ved at injicere superkritisk CO2 ned i Nordsøens kalkreservoirer kan man formentlig øge olieindvindingen med 15%. Metoden giver dog anledning til overvejelser om, hvorvidt processen kan føre til kollaps og/eller sprækkedannelse i reservoiret, og dermed om der er mulighed for lækage. Via laborator...

Updated follow-up of long-term Chalk River employees

International Nuclear Information System (INIS)

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

1983-08-01

Data on the follow-up of CRNL employees who died during employment or after retirement have been updated to 1982 December 31. Updated tables on mortality for AECL participants in the 1953 NRX clean-up and in the 1958 NRU decontamination are also included in this report. Preliminary mortality data on two other groups are presented here for (a) female employees of CRNL, 1966-1982 and (b) male employees of CRNL who have accumulated lifetime occupational doses of 0.2 Sv (20 rem) or more. Data on types of fatal cancer recorded for long-term male CRNL employees over the period 1966-1982 are also given. No statistically significant increases in cancer deaths were found in any of the groups analyzed

Isotopes as tracers in a contaminated fractured chalk aquitard

Science.gov (United States)

Nativ, R.; Adar, E.

2003-04-01

Clusters of industrial plants often generate contaminant plumes with several potential sources. Prevention of further pollution and designing suitable remedial measures require identification of the contributing source among all potential ones and the sorting of currently active sources from historical ones. In the study area, an industrial complex in the Negev desert, Israel, the lateral spread of groundwater contamination combined with water level patterns and the location of wastewater storage lagoons and treatment facilities posed a serious monitoring problem. Because (1) wastewater from all plants was mixed through a central wastewater pipeline and spread in various ways and means throughout the site, and (2) a groundwater mounding area was formed upgradient of the site, the contribution of potentially contaminating individual downgradient facilities could not be inferred using site-specific contaminants and/or the increased hydraulic head. Stable isotopes of oxygen, hydrogen and sulfur, as well as tritium, proved to be an efficient monitoring tool. Isotopic characterization of the two end members, namely, the natural, uncontaminated groundwater in off-site wells, and the industrial wastewater, provided the criteria for constraining a contaminating source when several alternative sources appeared viable. The isotopic fractionation of oxygen and hydrogen isotopes could be tied to the various disposal phases of the industrial wastewater. The presented case studies illustrate the important role of isotopes as tracers at contaminated sites.

Proceedings of the fifth international conference on CANDU fuel. V.1,2

International Nuclear Information System (INIS)

Lau, J.H.

1997-01-01

The First International Conference on CANDU Fuel was held in Chalk River in 1986. The CANDU Fuel community has gathered every three years since. The papers presented include topics on international experience, CANFLEX fuel bundles, Fuel design, Fuel modelling, Manufacturing and Quality assurance, Fuel performance and Safety, Fuel cycles and Spent Fuel management. Volume One was published in advance of the conference and Volume Two was printed after the conference

Necrotizing pancreatitis due to hypercalcemia in a hemodialysis patient with pica

OpenAIRE

Brener, Zachary Z.; Bergman, Michael

2014-01-01

Pica refers to the persistent, compulsive craving for and ingestion of nonfood items and certain food items. Pica is quite common among dialysis patients. The nutrient composition of some of the substances ingested may contribute to severe metabolic and mineral disturbances and other serious medical complications. We report the first case of a hemodialysis patient with chalk pica associated hypercalcemia who developed acute necrotizing pancreatitis. Hydration, nutritional support and hemodial...

NRX and NRU reactor research facilities and irradiation and examination charges

International Nuclear Information System (INIS)

1960-08-01

This report details the irradiation and examination charges on the NRX and NRU reactors at the Chalk River Nuclear Labs. It describes the NRX and NRU research facilities available to external users. It describes the various experimental holes and loops available for research. It also outlines the method used to calculate the facilities charges and the procedure for applying to use the facilities as well as the billing procedures.

Computer Presentation Programs and Teaching Research Methodologies

OpenAIRE

Motamedi, Vahid

2015-01-01

Supplementing traditional chalk and board instruction with computer delivery has been viewed positively by students who have reported increased understanding and more interaction with the instructor when computer presentations are used in the classroom. Some problems contributing to student errors while taking class notes might be transcription of numbers to the board, and handwriting of the instructor can be resolved in careful construction of computer presentations. The use of computer pres...

‘Good Building’: Bertolt Brecht’s Utopian Historical Optimism at the End of World War II

Directory of Open Access Journals (Sweden)

Gerhard Fischer

2011-04-01

Full Text Available The article focuses on the works of Bertolt Brecht which depicts his insights regarding the reconstruction of Germany. Such works include the story "The City Builder" and the plays "Caucasian Chalk Circle" and "The Days of the Commune." It discusses his principles of what he considers as good building as well as the three criteria addressed in good building which include size, time, and beauty.

Historical Geography of the Upper Tombigbee Valley.

Science.gov (United States)

1982-05-01

Green . Routledge and Kegan Paul, London. Evans, W.A. 1939 Gaines Trace in Monroe County, Mississippi. Journal of Mis- sissippi History 1:100-109. 1940...Tombigbee Sand is a narrow belt extending from northwestern Tishomingo County into Pickens and Greene counties in Alabama (Carr, 1954). Except in...prominent in Greene County, Alabama, and can be traced northwestward into Mississippi (Parsons, 1950;Johnson, 1976). The Demopolis Chalk overlies the

Proceedings of the fifth international conference on CANDU fuel. V.1,2

Energy Technology Data Exchange (ETDEWEB)

Lau, J H [ed.

1997-07-01

The First International Conference on CANDU Fuel was held in Chalk River in 1986. The CANDU Fuel community has gathered every three years since. The papers presented include topics on international experience, CANFLEX fuel bundles, Fuel design, Fuel modelling, Manufacturing and Quality assurance, Fuel performance and Safety, Fuel cycles and Spent Fuel management. Volume One was published in advance of the conference and Volume Two was printed after the conference.

Stable isotopes

International Nuclear Information System (INIS)

Evans, D.K.

1986-01-01

Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

Properties of rotational bands at the spin limit in A {approximately} 50, A {approximately} 65 and A {approximately} 110 nuclei

Energy Technology Data Exchange (ETDEWEB)

Janzen, V.P.; Andrews, H.R.; Ball, G.C. [Chalk River Labs., Ontario (Canada)] [and others

1996-12-31

There is now widespread evidence for the smooth termination of rotational bands in A {approx_equal} 110 nuclei at spins of 40-to-50{Dirac_h}s. The characteristics of these bands are compared to those of bands recently observed to high spin in {sup 64}Zn and {sup 48}Cr, studied with the 8{pi} {gamma}-ray spectrometer coupled to the Chalk River miniball charged-particle-detector array.

Design basis for creep of zirconium alloy components in a fast neutron flux

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Fidleris, V.

1975-01-01

The chalk River Nuclear Laboratory's experience with the creep of zirconium alloys in a neutron flux is described. Fast neutron flux changes the creep behaviour of zirconium alloys and new design criteria for in-reactor applications are needed. From experimental results empirical relations describing the effects of neutron flux, stress, temperature, time and anisotropy on creep rate were established. The relations are applied to the design of pressure tubes. (author)

Survey of physics research with a high duty cycle electron accelerator

International Nuclear Information System (INIS)

Bartholomew, G.A.; Earle, E.D.; Knowles, J.W.; Lone, M.A.

1981-02-01

The opportunities for nuclear physics research afforded by a CW electron linac with nominal energy 100 MeV and beam current >= 100 μA equipped with a bremsstrahlung monochromator and reaction product coincidence facilities are outlined. It is proposed that a program toward realization of an accelerator meeting these requirements and with provision for eventual extension to higher energies be undertaken at the Chalk River Nuclear Laboratories. (author)

Preliminary Tests of Gloss-Reduction and Coloring Agents for Camouflage of Polyvinyl Acetate Dust-Control Film

Science.gov (United States)

1976-02-01

extenders Kaolin powder Calcium carbonate dust Paint flatteners Celite h99 Nytal 1+00 Dry pigments Chalk dust (various colors) Liquid...a dispersant or wetting agent for satisfactory mixing. Vor this purpose, one of two agents was used: (a) a commercial 10 per- cent determent...pockets of unmixed powder, and in some cases the powder settled to the bottom of the mold. The dispersants that were tried did not effectively disperse

North-American MP Tandem accelerators

International Nuclear Information System (INIS)

Wegner, H.E.; Thieberger, P.

1977-01-01

There are six North-American MP Tandem accelerators: Yale; Minnesota; Chalk River; Rochester; and two at Brookhaven. The current status and operating characteristics of these six tandem accelerators are discussed. Upgrade and special improvements of the different machines is reviewed and new developments since the last Electrostatic Conference are discussed in detail. The overall operating characteristics of the different machines during the last year of operation are compared

Design basis for creep of zirconium alloy components in a fast neutron flux

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Fidleris, V.

1974-01-01

The Chalk River Nuclear Laboratory's experience with the creep of zirconium alloys in a neutron flux is described. Fast neutron flux changes the creep behavior of zirconium alloys and new design criteria for in-reactor applications are needed. From experimental results empirical relations describing the effects of neutron flux, stress, temperature, time, and anisotropy on creep rate were established. The relations are applied to the design of pressure tubes. (author)

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).

Use of clinical practice as a motivating tool of radioprotection teaching and radiopharmacology in early semesters of pharmacy course

International Nuclear Information System (INIS)

Andrighetto, Daniela; Lüdke, Everton

2014-01-01

The research teaching methods aimed at the success of the higher education student in pharmacology and medicine courses in technical expertise in the fields of radiological protection, radiopharmacology and interventional radiology is extremely important in view of the progress of these sectors. The objective of this work is to propose a methodological sequence of teaching work with first-year students of pharmacy and medicine courses within a biophysical discipline where the integrated knowledge to clinical practice can be used for this purpose. The methodology was to assess individual learning of a group of N = 49 students of the first half in the age group of 17-19 years through conceptual acquisition by the traditional method of 'blackboard and chalk' and developed method that includes four pedagogical moments focused on the area health. An analysis of the evaluation student performance through Variance Analysis of a pathway showed improved scores with respect to the performance of application issues of knowledge concerning radiation protection and biological mechanisms of radiation with respect to the method of 'blackboard and chalk' with p < 0.05. Therefore, work with students with respect to the content in the form of six steps of clinical interest are a promising technique for radiation protection education in the early grades of college courses with experimental effectiveness

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.)

A Microwave Driven Ion Source for Continuous-Flow AMS (Abstract)

International Nuclear Information System (INIS)

Wills, J.; Schneider, R.J.; Reden, K.F. von; Hayes, J.M.; Roberts, M.L.; Benthien, A.

2005-01-01

A microwave-driven, gas-fed ion source originally developed as a high-current positive ion injector for a Tandem accelerator at Chalk River has been the subject of a three-year development program at the Woods Hole Oceanographic Institution NOSAMS facility. Off-line tests have demonstrated positive carbon currents of 1 mA and negative carbon currents of 80 μA from CO2 gas feed. This source and a magnesium charge-exchange canal were coupled to the recombinator of the NOSAMS Tandetron for on-line tests, with the source fed with reference gasses and a combustion device.The promising results obtained have prompted the redesign of the microwave source for use as an on-line, continuous-flow injector for a new AMS facility under construction at NOSAMS. The new design is optimized for best transmission of the extracted positive-ion beam through the charge-exchange canal and for reliable operation at 40 kV extraction voltage. Other goals of the re-design include improved lifetime of the microwave window and the elimination of dead volumes in the plasma generator that increase sample hold-up time.This talk will include a summary of results obtained to date at NOSAMS with the Chalk River source and a detailed description of the new design

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.

Process for separating and recovering oil from oil-sands, etc

Energy Technology Data Exchange (ETDEWEB)

Preller, H

1921-02-24

A process for separating and recovering oil from oil-sands, bitumen from oil-chalk, oil-shale, and coal, according to Patent 400,122, is described. It is characterized in that the mined material falling on account of its weight is exposed to the running hot water in circulation through the wash-chamber and the clarifying chamber arranged separate or built on (circulation) being obtained by pumps or injectors in a regulatable motion.

Mathematical preliminaries to the advanced treatment of Hamiltonian dynamics

International Nuclear Information System (INIS)

Douglas, S.R.

1991-07-01

Hamilton's equations of motion and their solution are discussed from the viewpoints of geometry and algebra. The intention is to explain the mathematical underpinnings of the Lie algebraic methods due to A. Dragt and co-workers for solving problems in charged particle optics. Most of the important formulas in Lie algebraic optics are derived. These methods are being applied to the study of the particle trajectories in the superconducting cyclotron at Chalk River Laboratories

Effect of flow obstacles with various leading and trailing edges on critical heat flux

International Nuclear Information System (INIS)

Pioro, I.L.; Groeneveld, D.C.; Groeneveld, D.C.; Cheng, S.C.; Antoshko, Y.V.

2001-01-01

A joint investigation has been performed by the University of Ottawa and Chalk River Laboratories that examined the effect of the shape of the leading and trailing edges of the turbulence enhancing devices ('flow obstacles') on critical heat flux (CHF). The objective of this study was to gain a better overall understanding of the limit of CHF improvement for various obstacle designs and the impact of flow conditions on the improvements. (author)

Lessons learned from designing and commissioning a versatile data acquisiting system for an accelerator development facility

International Nuclear Information System (INIS)

Langlais, C.E.; Watkins, L.M.; Caissie, L.P.; Wachsmann, W.J.; Andison, C.E.

1977-01-01

Achieving reliable operation of digital equipment under extreme noise conditions presents special challenges to system designers. Experience with the design and operation of a data acquisition and control system for an accelerator development facility at the Chalk River Nuclear Laboratories is reviewed. It is concluded that, by adhering to a few rules in developing both the hardware and the software, satisfactory performance can be guaranteed. Methods of producing a reliable design are presented

A prototype NDT inspection data bank

International Nuclear Information System (INIS)

Wells, N.S.

1978-01-01

Existing reliability data banks provide information on items with catastrophic failure modes. However, many system components in a nuclear generating station, e.g., the steam generators, have a time-dependent degradation failure mode. Non-destructive tests associated with this failure mode require a different data base to permit predictive estimates of the component service life and performance. A data base suitable for this failure mode is presently being tested at Chalk River Nuclear Laboratories. (author)

A Novel Architecture for Intrusion Detection in Mobile Ad hoc Network

OpenAIRE

Atul Patel; Ruchi Kansara; Dr. Paresh Virparia

2011-01-01

Today’s wireless networks are vulnerable in many ways including illegal use, unauthorized access, denial of service attacks, eavesdropping so called war chalking. These problems are one of the main issues for wider uses of wireless network. On wired network intruder can access by wire but in wireless it has possibilities to access the computer anywhere in neighborhood. However, securing MANETs is highly challenging issue due to their inherent characteristics. Intrusion detection is an importa...

What Should Be Classified? A Framework with Application to the Global Force Management Data Initiative

Science.gov (United States)

2010-01-01

did so at the request of the Joint Staff to determine whether and to what extent the information that the ini- 6 In Gary Klein , Sources of Power: How...Parachini, William Rosenau, Erin M. Simpson, Melanie Sisson, and Donald Temple, Breaching the Fortress Wall: Understanding Terrorist Efforts to Overcome...briefing, May 30, 2008. Jackson, Brian A., Peter Chalk, R. Kim Cragin, Bruce Newsome, John V. Parachini, William Rosenau, Erin M. Simpson, Melanie Sisson

Beyond al-Qaeda. Part 2. The Outer Rings of the Terrorist Universe

Science.gov (United States)

2006-01-01

survey of the ideology of the FARC and ELN, see Rabasa and Chalk (2001). Colombia’s Fundacion Seguridad & Democracia has published a valuable series of...officer, Washington, D.C., August 2005. See also the data on combat operations in Fundacion Seguridad y Democracia (Bogotá), “Coyuntura de Seguridad ...89 Fundación Seguridad & Democracia , “Balance de seguridad en Colombia, Año 2003.” 90 Amnesty International, Colombia Report for 2005, http

Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada

Directory of Open Access Journals (Sweden)

Martha Patricia Celis-Salgado

2016-04-01

Full Text Available Smelting of sulphur-rich metallic ores in Sudbury, Ontario, Canada, has caused acidification and metal contamination of thousands of lakes in the region. Recent reductions in smelter emissions have resulted in much ecological recovery, but the recovery of Daphnia species has been poor. To determine if Cu and Ni toxicity could explain differences in daphniid recovery among lakes, we compared results of 14 d static with renewal bioassays in waters from Blue Chalk Lake, an uncontaminated reference lake 200 km from Sudbury, and from five Sudbury lakes ranging in distance from the smelters and varying in metal and cation concentrations. We spiked Blue Chalk Lake water with Cu and Ni to levels resembling those of the Sudbury lakes and also tested the lake waters for toxicity. Survival of Daphnia pulex, D. pulicaria and D. mendotae decreased monotonically with increasing metal concentrations in the spiked Blue Chalk Lake treatments, falling from 90% in the controls to 0% at the two highest Cu and Ni levels, reflecting levels of Middle and Hannah lakes. In contrast, survival in waters collected from the actual Sudbury lakes did not monotonically track their total metal concentrations. Rather, survival fell to 0% in Clearwater Lake water, a lake with intermediate metal contamination (8.9 and 79.9 μg L–1 of Cu and Ni, respectively vs 70-100% in the other lakes. We performed an additional assay with Clearwater Lake waters increasing its Ca and Na concentrations, singly and in combination to levels that reflected the levels in Middle Lake. The survival of the four daphniid species increased from 0% up to 80-100% with added Ca and from 0% to 60-90% with added Na. Lipid-ovarian indices had a similar trend to survival for D. mendotae and D. pulicaria in Bioassay 1, varying with the cation concentrations in the lakes for the daphniids in Bioassay 2. The bioassays results imply that regional recovery patterns of daphniids in Sudbury lakes cannot be understood

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

Progress report April 1, to June 30, 1956. Physics Division

Energy Technology Data Exchange (ETDEWEB)

NONE

1956-07-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from April 1, to June 30, 1956. It describes the research in nuclear physics, general physics; theoretical physics and electronics. The research areas covered in this report include nuclear reactions, nuclear decay, neutron capture gamma ray spectra, NRX production of plutonium and its higher isotopes, slow neutron spectrometry, neutron diffraction, gamma ray crystal spectrometry, theory of binary fission and analysis of neutron scattering data.

Progress report April 1, to June 30, 1956. Physics Division

International Nuclear Information System (INIS)

1956-01-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from April 1, to June 30, 1956. It describes the research in nuclear physics, general physics; theoretical physics and electronics. The research areas covered in this report include nuclear reactions, nuclear decay, neutron capture gamma ray spectra, NRX production of plutonium and its higher isotopes, slow neutron spectrometry, neutron diffraction, gamma ray crystal spectrometry, theory of binary fission and analysis of neutron scattering data.

Effects of Naloxone on Stress and Performance

Science.gov (United States)

1987-11-10

sixth honey sveep boaGt bu::::hel chalk cloci-: pri lll:e juicy unfold motor duke con !’ide scorn foWld route cliff socf:et moou locket syrup four...duchecs jostle coerce vcni~on vigil impetus resound tonic hyciene elude duplex diverse vital z.ellith poem gristle shre\\ld cough crct1.rny eagle...l:eener closed do cile profess IDllrine tutor gopher ethics chemist entice instep lyrical cured flourish scope mildew porter sleigh initial clique

TASCC newsletter volume 7 no. 2

International Nuclear Information System (INIS)

Thomson, L.

1993-02-01

A newsletter produced by Chalk River's Tandem Accelerator Superconducting Cyclotron Facility. Included in this February issue are notices on upcoming visits to TASCC by the Nuclear and Particle Physics Advisory Panel and a visit by the Deputy Minister of Industry, Science and Technology. The future of TASCC employees being of concern, a notice of terminations at AECL, none yet to TASCC. A facility report and the operating record plus a listing of experiments conducted in February

Attitude of medical students towards the use of audio visual aids during didactic lectures in pharmacology in a medical college of central India

OpenAIRE

Mehul Agrawal; Rajanish Kumar Sankdia

2016-01-01

Background: Students favour teaching methods employing audio visual aids over didactic lectures not using these aids. However, the optimum use of audio visual aids is essential for deriving their benefits. During a lecture, both the visual and auditory senses are used to absorb information. Different methods of lecture are and ndash; chalk and board, power point presentations (PPT) and mix of aids. This study was done to know the students' preference regarding the various audio visual aids, ...

THE GLOBAL ZERO MOVEMENT: A ROAD TO NOWHERE

Science.gov (United States)

2016-02-08

persistence.”1 The underlying foundations of the Global Zero movement date back to the 1980s under the Reagan era as noted on the Global Zero website...and his colleagues.7 Presidential Candidate, Barack Obama Supports Global Zero One of those leaders was then Presidential candidate, Barack Obama...movement. In their eyes, this could be chalked up as one of the first major “wins” for the Global Zero movement. 6 As the motivations for Iran

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)

Habitat segregation in fish assemblages

OpenAIRE

Ibbotson, A.T.

1990-01-01

The segregation of habitats of fish assemblages found in the chalk streams and rivers within the Wessex, South West and Southern Water Authority boundaries in southern England have been examined. Habitat segregation is the most frequent type of resource partitioning in natural communities. The habitat of individual fish species will be defined in order to determine the following: (1) the requirements of each species in terms of depth, current velocity, substrate, cover etc.; (2) identify the ...

The Chalk River Nuclear Laboratories contingency plan -a brief description

International Nuclear Information System (INIS)

White, J.M.

1982-01-01

A brief description of the contingency plan which deals with both the on-site and off-site consequences of a serious nuclear accident is given. The off-site consequences of different size releases and the subsequent action taken by employees, radiation protection experts, municipal, Provincial and Federal authorities is described and the interaction of the various groups is discussed. (author)

Diffusive parameters of tritiated water (HTO) and U in chalk

International Nuclear Information System (INIS)

Descostes, M.; Gandois, O.; Frasca, B.; Radwan, J.; Juery, A.; Descostes, M.; Pili, E.

2009-01-01

Complete text of publication follows: The feasibility of aquifer storage and recovery systems (ASR) to counteract short and long term imbalances between freshwater supply and demand is currently investigated for the metropolitan area of Perth, Western Australia. During the planned injection of oxic excess water into a deep anoxic aquifer the water quality evolution will depend on the extent and structure of the physical and geochemical heterogeneity and reactivity of the aquifer. A detailed geochemical characterisation was undertaken to determine amount and type of sedimentary reductants within different lithological facies. The incubation of sediment samples from the target aquifer for ∼ 52 days enabled quantification of their oxygen (O 2 ) consumption and CO 2 production [1]. Data analysis, in particular the identification of key redox and acid buffering processes, was under-pinned by hydrogeochemical modelling. Results showed that the average measured reductive capacities (MRC) towards O 2 consumption increased from the sand facies, followed by the siltstone facies, and the mud-stone/shale facies. This approach identified pyrite (20 - 100%), sedimentary organic matter (SOM; 3 - 56%), siderite (3 - 28%) and Fe(II)- aluminosilicates (8 - 55%) as the main O 2 reductants. Minute amounts of carbonate acted as buffering minerals, while a bounding pH of 3 indicated acid buffering by K-feldspar dissolution. The supernatants showed elevated aqueous concentrations of Ni, Cd and Pb to be a potential risk for the quality of the recovered water. [1] Hartog, Griffioen and Van der Weijden (2002) Environmental Science and Technology 36(11), 2338-2344

The control computer for the Chalk River electron test accelerator

International Nuclear Information System (INIS)

McMichael, G.E.; Fraser, J.S.; McKeown, J.

1978-02-01

A versatile control and data acquisition system has been developed for a modest-sized linear accelerator using mainly process I/O hardware and software. This report describes the evolution of the present system since 1972, the modifications needed to satisfy the changing requirements of the various accelerator physics experiments and the limitations of such a system in process control. (author)

Combined rock slope stability and shallow landslide susceptibility assessment of the Jasmund cliff area (Rügen Island, Germany

Directory of Open Access Journals (Sweden)

A. Günther

2009-05-01

Full Text Available In this contribution we evaluated both the structurally-controlled failure susceptibility of the fractured Cretaceous chalk rocks and the topographically-controlled shallow landslide susceptibility of the overlying glacial sediments for the Jasmund cliff area on Rügen Island, Germany. We employed a combined methodology involving spatially distributed kinematical rock slope failure testing with tectonic fabric data, and both physically- and inventory-based shallow landslide susceptibility analysis. The rock slope failure susceptibility model identifies areas of recent cliff collapses, confirming its value in predicting the locations of future failures. The model reveals that toppling is the most important failure type in the Cretaceous chalk rocks of the area. The shallow landslide susceptibility analysis involves a physically-based slope stability evaluation which utilizes material strength and hydraulic conductivity data, and a bivariate landslide susceptibility analysis exploiting landslide inventory data and thematic information on ground conditioning factors. Both models show reasonable success rates when evaluated with the available inventory data, and an attempt was made to combine the individual models to prepare a map displaying both terrain instability and landslide susceptibility. This combination highlights unstable cliff portions lacking discrete landslide areas as well as cliff sections highly affected by past landslide events. Through a spatial integration of the rock slope failure susceptibility model with the combined shallow landslide assessment we produced a comprehensive landslide susceptibility map for the Jasmund cliff area.

Toxicity of fluorescent tracers and their degradation byproducts

Directory of Open Access Journals (Sweden)

Philippe Gombert

2017-01-01

Full Text Available Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

Use of clinical practice as a motivating tool of radioprotection teaching and radiopharmacology in early semesters of pharmacy course; Uso da pratica clinica como ferramenta motivadora de ensino de radioprotecao e radiofarmacologia em semestres iniciais em cursos de farmacia

Energy Technology Data Exchange (ETDEWEB)

Andrighetto, Daniela; Lüdke, Everton, E-mail: daniela.andrighetto@hotmail.com, E-mail: evertonludke@gmail.com [Universidade Federal de Santa Maria (CCNE/DEFIS/UFSM), RS (Brazil). Departamento de Fisica

2014-07-01

The research teaching methods aimed at the success of the higher education student in pharmacology and medicine courses in technical expertise in the fields of radiological protection, radiopharmacology and interventional radiology is extremely important in view of the progress of these sectors. The objective of this work is to propose a methodological sequence of teaching work with first-year students of pharmacy and medicine courses within a biophysical discipline where the integrated knowledge to clinical practice can be used for this purpose. The methodology was to assess individual learning of a group of N = 49 students of the first half in the age group of 17-19 years through conceptual acquisition by the traditional method of 'blackboard and chalk' and developed method that includes four pedagogical moments focused on the area health. An analysis of the evaluation student performance through Variance Analysis of a pathway showed improved scores with respect to the performance of application issues of knowledge concerning radiation protection and biological mechanisms of radiation with respect to the method of 'blackboard and chalk' with p < 0.05. Therefore, work with students with respect to the content in the form of six steps of clinical interest are a promising technique for radiation protection education in the early grades of college courses with experimental effectiveness.

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

Field test of wireless sensor network in the nuclear environment

International Nuclear Information System (INIS)

Li, L.; Wang, Q.; Bari, A.; Deng, C.; Chen, D.; Jiang, J.; Alexander, Q.; Sur, B.

2014-01-01

Wireless sensor networks (WSNs) are appealing options for the health monitoring of nuclear power plants due to their low cost and flexibility. Before they can be used in highly regulated nuclear environments, their reliability in the nuclear environment and compatibility with existing devices have to be assessed. In situ electromagnetic interference tests, wireless signal propagation tests, and nuclear radiation hardness tests conducted on candidate WSN systems at AECL Chalk River Labs are presented. The results are favourable to WSN in nuclear applications. (author)

The Narcotics Counterinsurgency Dilemma

Science.gov (United States)

2008-05-22

government. Following a ten year civil war in the 1950’s, referred to as La Violencia , the central government never re-established authority and control...www.monitor.upeace.org/Colombia.pdf 21 Norman Bailey, “La Violencia in Colombia,” Journal of Inter-American Studies 9, no. 4 (1967): 561. 22 Peter Chalk and Angel...reach required across all regions of the country along with the traditional familiarity . The use of mic grants and micro-loans to jump start small

Field test of wireless sensor network in the nuclear environment

Energy Technology Data Exchange (ETDEWEB)

Li, L., E-mail: lil@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Wang, Q.; Bari, A. [Univ. of Western Ontario, London, Ontario (Canada); Deng, C.; Chen, D. [Univ. of Electronic Science and Technology of China, Chengdu, Sichuan (China); Jiang, J. [Univ. of Western Ontario, London, Ontario (Canada); Alexander, Q.; Sur, B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2014-06-15

Wireless sensor networks (WSNs) are appealing options for the health monitoring of nuclear power plants due to their low cost and flexibility. Before they can be used in highly regulated nuclear environments, their reliability in the nuclear environment and compatibility with existing devices have to be assessed. In situ electromagnetic interference tests, wireless signal propagation tests, and nuclear radiation hardness tests conducted on candidate WSN systems at AECL Chalk River Labs are presented. The results are favourable to WSN in nuclear applications. (author)

Human Resources Development for Rooppur Nuclear Power Programme in Bangladesh

International Nuclear Information System (INIS)

Hossain, Md. Kabir

2014-01-01

Conclusions: • Bangladesh faces a huge challenge in implementing the Rooppur NPP and its total nuclear power; • A preliminary assessment has been chalked out a plan to find out methods that can be applied to find out our gaps and then fill them up; • Bangladesh seeks cooperation from the Russian Federation in the form assistance package like National training courses, Seminar/Workshop, Expert Mission/Review and other form of bilateral arrangements in establishing infrastructure for “Rooppur NPP” building;

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.

Studies of reactor waste conditioning and disposal at CRNL

International Nuclear Information System (INIS)

Beamer, N.V.; Bourne, W.T.; Buckely, L.P.; Pettipas, W.H.; Burrill, K.A.; Dixon, D.F.; Charlesworth, D.H.

1982-09-01

This report is a compilation of five papers presented at the Second Annual Meeting of the Canadian Nuclear Society in Ottawa, 1981 June. These papers describe recent progress in studies being conducted at the Chalk River Nuclear Laboratories related to the permanent disposal of low-and intermediate-level wastes arising in the Canadian nuclear industry. The principal topics discussed include waste processing by incineration, ultrafiltration and reverse osmosis, immobilization in bitumen and glass, and also the strategy for disposal of the conditioned wastes

Examination of TL and optical absorption in calcite's mineral

International Nuclear Information System (INIS)

Sabikoglu, I.; Can, N.

2009-01-01

Calcite which is a form of crystalline of the calcium carbonate composes parent material of chalk stone (limestone) and marble. Calcite which presents in various colors also in our country consists of yellow, blue, transparent and green colors. In this study, green calcite mineral which is taken from the region of Ayvalik, was examined of its thermoluminescence (TL) and optical absorption features in different doses. It has been obtained a large TL peak in 179 degree C and absorption peak in 550 mm.

The use of Hewlett Packard minicomputers for data acquisition and data analysis in heat exchanger research and development

International Nuclear Information System (INIS)

Lepp, R.M.; Mastorakos, J.; Shaw, J.D.; Tromp, J.H.

1984-07-01

Failures in heat exchange equipment are usually caused by vibration-induced fatigue or fretting wear, or by corrosion. The need for high reliability and performance of this equipment, particularly in nuclear power plants, has resulted in research and development programs on heat exchangers at the Chalk River Nuclear Laboratories. Much of this work has been experimental, requiring the use of computer-based data acquisition/analysis systems. The way in which we have satisfied these needs using equipment supplied by Hewlett-Packard is described