30 CFR 250.456 - What safe practices must the drilling fluid program follow?

Code of Federal Regulations, 2011 CFR

2011-07-01

... fluid. You must circulate a volume of drilling fluid equal to the annular volume with the drill pipe... fluid volume needed to fill the hole. Both sets of numbers must be posted near the driller's station... warrant. Your tests must conform to industry-accepted practices and include density, viscosity, and gel...

Methods to ensure optimal off-bottom and drill bit distance under pellet impact drilling

NASA Astrophysics Data System (ADS)

Kovalyov, A. V.; Isaev, Ye D.; Vagapov, A. R.; Urnish, V. V.; Ulyanova, O. S.

2016-09-01

The paper describes pellet impact drilling which could be used to increase the drilling speed and the rate of penetration when drilling hard rock for various purposes. Pellet impact drilling implies rock destruction by metal pellets with high kinetic energy in the immediate vicinity of the earth formation encountered. The pellets are circulated in the bottom hole by a high velocity fluid jet, which is the principle component of the ejector pellet impact drill bit. The paper presents the survey of methods ensuring an optimal off-bottom and a drill bit distance. The analysis of methods shows that the issue is topical and requires further research.

Leak-off mechanism and pressure prediction for shallow sediments in deepwater drilling

NASA Astrophysics Data System (ADS)

Tan, Qiang; Deng, Jingen; Sun, Jin; Liu, Wei; Yu, Baohua

2018-02-01

Deepwater sediments are prone to loss circulation in drilling due to a low overburden gradient. How to predict the magnitude of leak-off pressure more accurately is an important issue in the protection of drilling safety and the reduction of drilling cost in deep water. Starting from the mechanical properties of a shallow formation and based on the basic theory of rock-soil mechanics, the stress distribution around a borehole was analyzed. It was found that the rock or soil on a borehole is in the plastic yield state before the effective tensile stress is generated, and the effective tangential and vertical stresses increase as the drilling fluid density increases; thus, tensile failure will not occur on the borehole wall. Based on the results of stress calculation, two mechanisms and leak-off pressure prediction models for shallow sediments in deepwater drilling were put forward, and the calculated values of these models were compared with the measured value of shallow leak-off pressure in actual drilling. The results show that the MHPS (minimum horizontal principle stress) model and the FIF (fracturing in formation) model can predict the lower and upper limits of leak-off pressure. The PLC (permeable lost circulation) model can comprehensively analyze the factors influencing permeable leakage and provide a theoretical basis for leak-off prevention and plugging in deepwater drilling.

Research and application of borehole structure optimization based on pre-drill risk assessment

NASA Astrophysics Data System (ADS)

Zhang, Guohui; Liu, Xinyun; Chenrong; Hugui; Yu, Wenhua; Sheng, Yanan; Guan, Zhichuan

2017-11-01

Borehole structure design based on pre-drill risk assessment and considering risks related to drilling operation is the pre-condition for safe and smooth drilling operation. Major risks of drilling operation include lost circulation, blowout, sidewall collapsing, sticking and failure of drilling tools etc. In the study, studying data from neighboring wells was used to calculate the profile of formation pressure with credibility in the target well, then the borehole structure design for the target well assessment by using the drilling risk assessment to predict engineering risks before drilling. Finally, the prediction results were used to optimize borehole structure design to prevent such drilling risks. The newly-developed technique provides a scientific basis for lowering probability and frequency of drilling engineering risks, and shortening time required to drill a well, which is of great significance for safe and high-efficient drilling.

Test drilling in basalts, Lalamilo area, South Kohala District, Hawaii

USGS Publications Warehouse

Teasdale, Warren E.

1980-01-01

Test drilling has determined that a downhole-percussion airhammer can be used effectively to drill basalts in Hawaii. When used in conjunction with a foam-type drilling fluid, the hammer-bit penetration rate was rapid. Continuous drill cuttings from the materials penetrated were obtained throughout the borehole except from extremely fractured or weathered basalt zones where circulation was lost or limited. Cementing of these zones as soon as encountered reduced problems of stuck tools, washouts, and loss of drill-cuttings. Supplies and logistics on the Hawaiian Islands, always a major concern, require that all anticipated drilling supplies, spare rig and tool parts, drilling muds and additives, foam, and miscellaneous hardware be on hand before starting to drill. If not, the resulting rig downtime is costly in both time and money. (USGS)

Thermal indicator for wells

DOEpatents

Gaven, Jr., Joseph V.; Bak, Chan S.

1983-01-01

Minute durable plate-like thermal indicators are employed for precision measuring static and dynamic temperatures of well drilling fluids. The indicators are small enough and sufficiently durable to be circulated in the well with drilling fluids during the drilling operation. The indicators include a heat resistant indicating layer, a coacting meltable solid component and a retainer body which serves to unitize each indicator and which may carry permanent indicator identifying indicia. The indicators are recovered from the drilling fluid at ground level by known techniques.

Results of temperature gradient and heat flow in Santiam Pass Area, Oregon, Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, B.L.; Gardner, M.C.; Koenig, J.B.

The conclusions of this report are: (1) There is a weakly defined thermal anomaly within the area examined by temperature-gradient holes in the Santiam Pass area. This is a relict anomaly showing differences in permeability between the High Cascades and Western Cascades areas, more than a fundamental difference in shallow crustal temperatures. (2) The anomaly as defined by the 60 F isotherms at 400 feet follows a north-south trend immediately westward of the Cascade axis in the boundary region. It is clear that all holes spudded into High Cascades rocks result in isothermal and reversal gradients. Holes spudded in Westernmore » Cascades rocks result in positive gradients. (3) Cold groundwater flow influences and masks temperature gradients in the High Cascades to a depth of at least 700 feet, especially eastward from the major north-south trending faults. Pleistocene and Holocene rocks are very permeable aquifers. (4) Shallow gradient drilling in the lowlands westward of the faults provides more interpretable information than shallow drilling in the cold-water recharge zones. Topographic and climatological effects can be filtered out of the temperature gradient results. (5) The thermal anomaly seems to have 2 centers: one in the Belknap-Foley area, and one northward in the Sand Mountain area. The anomalies may or may not be connected along a north-south trend. (6) A geothermal effect is seen in holes downslope of the Western-High Cascade boundary. Mixing with cold waters is a powerful influence on temperature gradient data. (7) The temperature-gradient program has not yet examined and defined the geothermal resources potential of the area eastward of the Western Cascades-High Cascades boundary. Holes to 1500-2000 feet in depth are required to penetrate the high permeability-cold groundwater regime. (8) Drilling conditions are unfavorable. There are very few accessible level drill sites. Seasonal access problems and environmental restrictions together with frequent lost circulation results in very high costs per foot drilled.« less

El Paso County Geothermal Project at Fort Bliss. Final Project Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lear, Jon; Bennett, Carlon; Lear, Dan

The El Paso County Geothermal Project at Fort Bliss was an effort to determine the scale and scope of geothermal resources previously identified on Fort Bliss’ McGregor Range in southern Otero County, New Mexico. The project was funded with a $5,000,000 grant to El Paso County from the U.S. Department of Energy (DOE) as part of the American Recovery and Reinvestment Act of 2009 and a $4,812,500 match provided by private sector partners. The project was administered through the DOE Golden Field Office to awardee El Paso County. The primary subcontractor to El Paso County and project Principal Investigator -more » Ruby Mountain Inc. (RMI) of Salt Lake City, Utah - assembled the project team consisting of Evergreen Clean Energy Management (ECEM) of Provo, Utah, and the Energy & Geoscience Institute at the University of Utah (EGI) in Salt Lake City, UT to complete the final phases of the project. The project formally began in May of 2010 and consisted of two preliminary phases of data collection and evaluation which culminated in the identification of a drilling site for a Resource Confirmation Well on McGregor Range. Well RMI 56-5 was drilled May and June 2013 to a depth of 3,030 ft. below ground level. A string of slotted 7 inch casing was set in 8.75 inch hole on bottom fill at 3,017 ft. to complete the well. The well was drilled using a technique called flooded reverse circulation, which is most common in mineral exploration. This technique produced an exceptionally large and complete cuttings record. An exciting development at the conclusion of drilling was the suspected discovery of a formation that has proven to be of exceptionally high permeability in three desalinization wells six miles to the south. Following drilling and preliminary testing and analysis, the project team has determined that the McGregor Range thermal anomaly is large and can probably support development in the tens of megawatts.« less

Reverse laser drilling

NASA Technical Reports Server (NTRS)

Anthony, Thomas R. (Inventor)

1984-01-01

This invention provides a method for laser drilling small diameter, closely-spaced, and accurately located holes in a body of material which is transparent or substantially transparent to the laser radiation employed whereby the holes are drilled through the thickness of the body from the surface opposite to that on which the laser beam impinges to the surface of laser beam impingement.

The Iceland Deep Drilling Project 4.5 km deep well, IDDP-2, in the seawater-recharged Reykjanes geothermal field in SW Iceland has successfully reached its supercritical target

NASA Astrophysics Data System (ADS)

Friðleifsson, Guðmundur Ó.; Elders, Wilfred A.; Zierenberg, Robert A.; Stefánsson, Ari; Fowler, Andrew P. G.; Weisenberger, Tobias B.; Harðarson, Björn S.; Mesfin, Kiflom G.

2017-11-01

The Iceland Deep Drilling Project research well RN-15/IDDP-2 at Reykjanes, Iceland, reached its target of supercritical conditions at a depth of 4.5 km in January 2017. After only 6 days of heating, the measured bottom hole temperature was 426 °C, and the fluid pressure was 34 MPa. The southern tip of the Reykjanes peninsula is the landward extension of the Mid-Atlantic Ridge in Iceland. Reykjanes is unique among Icelandic geothermal systems in that it is recharged by seawater, which has a critical point of 406 °C at 29.8 MPa. The geologic setting and fluid characteristics at Reykjanes provide a geochemical analog that allows us to investigate the roots of a mid-ocean ridge submarine black smoker hydrothermal system. Drilling began with deepening an existing 2.5 km deep vertical production well (RN-15) to 3 km depth, followed by inclined drilling directed towards the main upflow zone of the system, for a total slant depth of 4659 m ( ˜ 4.5 km vertical depth). Total circulation losses of drilling fluid were encountered below 2.5 km, which could not be cured using lost circulation blocking materials or multiple cement jobs. Accordingly, drilling continued to the total depth without return of drill cuttings. Thirteen spot coring attempts were made below 3 km depth. Rocks in the cores are basalts and dolerites with alteration ranging from upper greenschist facies to amphibolite facies, suggesting that formation temperatures at depth exceed 450 °C. High-permeability circulation-fluid loss zones (feed points or feed zones) were detected at multiple depth levels below 3 km depth to bottom. The largest circulation losses (most permeable zones) occurred between the bottom of the casing and 3.4 km depth. Permeable zones encountered below 3.4 km accepted less than 5 % of the injected water. Currently, the project is attempting soft stimulation to increase deep permeability. While it is too early to speculate on the energy potential of this well and its economics, the IDDP-2 is a milestone in the development of geothermal resources and the study of hydrothermal systems. It is the first well that successfully encountered supercritical hydrothermal conditions, with potential high-power output, and in which on-going hydrothermal metamorphism at amphibolite facies conditions can be observed. The next step will be to carry out flow testing and fluid sampling to determine the chemical and thermodynamic properties of the formation fluids.

NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyons, K.D.; Honeygan, S.; Moroz, T.H.

2008-12-01

The U.S. Department of Energy's National Energy Technology Laboratory (NETL) established the Extreme Drilling Laboratory to engineer effective and efficient drilling technologies viable at depths greater than 20,000 ft. This paper details the challenges of ultradeep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL's research and development activities. NETL is invested in laboratory-scale physical simulation. Its physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480°F around a single drill cutter. This simulator is not yet operational; therefore, the results will be limited to themore » identification of leading hypotheses of drilling phenomena and NETL's test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Laboratory's studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.« less

An experimental system for coiled tubing partial underbalanced drilling (CT-PUBD) technique

NASA Astrophysics Data System (ADS)

Shi, H. Z.; Ji, Z. S.; Zhao, H. Q.; Chen, Z. L.; Zhang, H. Z.

2018-05-01

To improve the rate of penetration (ROP) in hard formations, a new high-speed drilling technique called Coiled Tubing Partial Underbalanced Drilling (CT-PUBD) is proposed. This method uses a rotary packer to realize an underbalanced condition near the bit by creating a micro-annulus and an overbalanced condition at the main part of the annulus. A new full-scale laboratory experimental system is designed and set up to study the hydraulic characteristics and drilling performance of this method. The system is composed of a drilling system, circulation system, and monitor system, including three key devices, namely, cuttings discharge device, rotary packer, and backflow device. The experimental results showed that the pressure loss increased linearly with the flow rate of the drilling fluid. The high drilling speed of CT-PUBD proved it a better drilling method than the conventional drilling. The experimental system may provide a fundamental basis for the research of CT-PUBD, and the results proved that this new method is feasible in enhancing ROP and guaranteeing the drilling safety.

Temperature and volume estimation of under-seafloor fluid from the logging-while-drilling data beneath an active hydrothermal field

NASA Astrophysics Data System (ADS)

Hamada, Y.; Saito, S.; Sanada, Y.; Masaki, Y.; Moe, K.; Kido, Y. N.; Kumagai, H.; Takai, K.; Suzuki, K.

2015-12-01

In July of 2014, offshore drillings on Iheya-North Knoll, Okinawa Trough, was executed as part of Next-generation technology for ocean resources survey, which is a research program in Cross-ministerial Strategic Innovation Promotion Program (SIP). In this expedition, logging-while- drilling (LWD) and measuring-while-drilling (MWD) were inserted into 6 holes (C9011 - C9016) to investigate spatial distribution of hydrothermal deposit and geothermal fluid reservoir. Both of these tools included annular pressure-while-drilling (APWD). Annular pressure and temperature were monitored by the APWD to detect possible exceedingly-high-temperature geofluid. In addition, drilling fluid was continuously circulated at sufficient flow rate to protect LWD tools against high temperature (non-stop driller system). At C9012 and C9016, the LWD tool clearly detected pressure and temperature anomaly at 234 meter below the seafloor (mbsf) and 80 mbsf, respectively. Annular pressure and temperature quickly increases at that depth and it would reflect the injection of high-temperature fluid. During the drilling, however, drilling water was continuously circulated at high flow-rate (2600L/min) and the measured temperature is not exactly in-situ temperature. To investigate the detail of the heat source, such as in-situ temperature and quantity of heat, we performed numerical analyses of thermal fluid and energy-balance assuming injection of high-temperature fluid. We combined pressure loss theory of double cylinders and temperature equation to replicate the fluid flow and its temperature between borehole wall and drilling pipe during the thermofluid injection. As the result, we estimated the temperature and the volume of injected fluid to be 115oC~ and 17.3 m3, respectively (at C9012) from the calculation. This temperature is lower than that of a hydrothermall vent which had been found near the hole (300oC).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gavignet, A.A.; Wick, C.J.

In current practice, pressure drops in the mud circulating system and the settling velocity of cuttings are calculated with simple rheological models and simple equations. Wellsite computers now allow more sophistication in drilling computations. In this paper, experimental results on the settling velocity of spheres in drilling fluids are reported, along with rheograms done over a wide range of shear rates. The flow curves are fitted to polynomials and general methods are developed to predict friction losses and settling velocities as functions of the polynomial coefficients. These methods were incorporated in a software package that can handle any rig configurationmore » system, including riser booster. Graphic displays show the effect of each parameter on the performance of the circulating system.« less

NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyons, K.D.; Honeygan, S.; Moroz, T

2007-06-01

The U.S. Department of Energy’s National Energy Technology Laboratory (NETL) established an Extreme Drilling Lab to engineer effective and efficient drilling technologies viable at depths greater than 20,000 feet. This paper details the challenges of ultra-deep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL’s Research and Development activities. NETL is invested in laboratory-scale physical simulation. Their physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480 °F around a single drill cutter. This simulator will not yet be operational by the planned conference dates; therefore,more » the results will be limited to identification of leading hypotheses of drilling phenomena and NETL’s test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Lab’s studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.« less

Aerated drilling cutting transport analysis in geothermal well

NASA Astrophysics Data System (ADS)

Wakhyudin, Aris; Setiawan, Deni; Dwi Marjuan, Oscar

2017-12-01

Aeratad drilling widely used for geothermal drilling especially when drilled into predicted production zone. Aerated drilling give better performance on preventing lost circulation problem, improving rate of penetration, and avoiding drilling fluid invasion to productive zone. While well is drilled, cutting is produced and should be carried to surface by drilling fluid. Hole problem, especially pipe sticking will occur while the cutting is not lifted properly to surface. The problem will effect on drilling schedule; non-productive time finally result more cost to be spent. Geothermal formation has different characteristic comparing oil and gas formation. Geothermal mainly has igneous rock while oil and gas mostly sedimentary rock. In same depth, formation pressure in geothermal well commonly lower than oil and gas well while formation temperature geothermal well is higher. While aerated drilling is applied in geothermal well, Igneous rock density has higher density than sedimentary rock and aerated drilling fluid is lighter than water based mud hence minimum velocity requirement to transport cutting is larger than in oil/gas well drilling. Temperature and pressure also has impact on drilling fluid (aerated) density. High temperature in geothermal well decrease drilling fluid density hence the effect of pressure and temperature also considered. In this paper, Aerated drilling cutting transport performance on geothermal well will be analysed due to different rock and drilling fluid density. Additionally, temperature and pressure effect on drilling fluid density also presented to merge.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khin, J.A.

Since reopening to foreign operators in 1989, companies have secured concessions and begun active exploration programs. This paper reports on: Yukong Oil (Block C) spudded well Indaw YK-1 last December and continued drilling below 8,500 ft. Well encountered frequent gas cut mud as well as lost circulation. BHP (Block H) spudded the Kawliya-1 in March this year and drilled to 6,500 ft. The well was dry and abandoned BHP plans to drill another well this year. Unocal (Block F) spudded its first well, the Kandaw-1, in May and plans to drill to 14,500 ft. Shell (Block G) began its firstmore » well in June. Shell's drilling program will consist of drilling four to six wells. Idemitsu (Block D) also spudded its first well in June. PetroCanada (Block E) plans to spud a well by December. Target depth is 12,000 ft.« less

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jill S. Buckley; Norman R. Morrow

2006-01-01

The objectives of this project are: (1) to improve understanding of the wettability alteration of mixed-wet rocks that results from contact with the components of synthetic oil-based drilling and completion fluids formulated to meet the needs of arctic drilling; (2) to investigate cleaning methods to reverse the wettability alteration of mixed-wet cores caused by contact with these SBM components; and (3) to develop new approaches to restoration of wetting that will permit the use of cores drilled with SBM formulations for valid studies of reservoir properties.

Project scientists discover magnetic phenomenon under Bermuda Rise

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-05-01

Drilling results in water depths of 18,000 ft between Puerto Rico and Bermuda indicate strong magnetic reverses occur in the rocks underlying the seabed. These and other findings during a cruise of the Glomar Challenger are reported. Information is included on the location of magnetic anomalies, sedimentation, and open-sea drilling. (JRD)

Reverse engineering of wörner type drilling machine structure.

NASA Astrophysics Data System (ADS)

Wibowo, A.; Belly, I.; llhamsyah, R.; Indrawanto; Yuwana, Y.

2018-03-01

A product design needs to be modified based on the conditions of production facilities and existing resource capabilities without reducing the functional aspects of the product itself. This paper describes the reverse engineering process of the main structure of the wörner type drilling machine to obtain a machine structure design that can be made by resources with limited ability by using simple processes. Some structural, functional and the work mechanism analyzes have been performed to understand the function and role of each basic components. The process of dismantling of the drilling machine and measuring each of the basic components was performed to obtain sets of the geometry and size data of each component. The geometric model of each structure components and the machine assembly were built to facilitate the simulation process and machine performance analysis that refers to ISO standard of drilling machine. The tolerance stackup analysis also performed to determine the type and value of geometrical and dimensional tolerances, which could affect the ease of the components to be manufactured and assembled

Drilling into molten rock at Kilauea Iki

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colp, J.L.; Okamura, R.T.

1978-01-01

The scientific feasibility of extracting energy directly from buried circulating magma resources is being assessed. One of the tasks of the project is the study of geophysical measuring systems to locate and define buried molten rock bodies. To verify the results of a molten rock sensing experiment performed at Kilauea Iki lava lake, it is necessary to drill a series of holes through the solid upper crust and through the molten zone at that location. Thirteen holes have been drilled in Kilauea Iki. The results achieved during the drilling of the last two holes indicated that the molten zone inmore » Kilauea Iki is not a simple, relatively homogeneous fluid body as expected. The encountering of an unexpected, unknown rigid obstruction 2.5 ft below the crust/melt interface has led to the conceptual development of a drilling system intended to have the capability to drill through a hot, rigid obstruction while the drill stem is immersed in molten rock. The concept will be field tested at Kilauea Iki in the summer of 1978.« less

A Low-Cost Indigenous Intervention which has Revolutionized the Drilling Technology and Changed the Life of Millions of Farmers in the State of Uttar Pradesh, India

NASA Astrophysics Data System (ADS)

Chaurasia, Pratik Ranjan; Subhash

2018-06-01

An unknown indigenous driller combined the percussion and circulation drilling principles, resulting in the development of low cost, low weight manual boring set in the year 1990-1991/1991-1992, which revolutionized the shallow well drilling technology and made possible to drill about 4.5 million shallow bore wells in the State. This has changed the landscape of irrigated agriculture, changing the life of millions of small and marginal farmers and contributed a lot in increasing crop production and crop productivity. The developed drilling equipment locally known as "Pressure Boring Set" is manually operated, low cost and can be transported on bicycles. Drilling cost is also less. This low cost and simple technology made it possible to drill large number of shallow bore wells in comparatively short time span and less cost, consequently enhancing the rate of increase in irrigated area and in turn crop production and productivity. Cost of the boring set is also low, as compared to traditional sand pump hand boring set and suitable for alluvial areas.

A Low-Cost Indigenous Intervention which has Revolutionized the Drilling Technology and Changed the Life of Millions of Farmers in the State of Uttar Pradesh, India

NASA Astrophysics Data System (ADS)

Chaurasia, Pratik Ranjan; Subhash

2018-02-01

An unknown indigenous driller combined the percussion and circulation drilling principles, resulting in the development of low cost, low weight manual boring set in the year 1990-1991/1991-1992, which revolutionized the shallow well drilling technology and made possible to drill about 4.5 million shallow bore wells in the State. This has changed the landscape of irrigated agriculture, changing the life of millions of small and marginal farmers and contributed a lot in increasing crop production and crop productivity. The developed drilling equipment locally known as "Pressure Boring Set" is manually operated, low cost and can be transported on bicycles. Drilling cost is also less. This low cost and simple technology made it possible to drill large number of shallow bore wells in comparatively short time span and less cost, consequently enhancing the rate of increase in irrigated area and in turn crop production and productivity. Cost of the boring set is also low, as compared to traditional sand pump hand boring set and suitable for alluvial areas.

Accuracy of patient-specific guided glenoid baseplate positioning for reverse shoulder arthroplasty.

PubMed

Levy, Jonathan C; Everding, Nathan G; Frankle, Mark A; Keppler, Louis J

2014-10-01

The accuracy of reproducing a surgical plan during shoulder arthroplasty is improved by computer assistance. Intraoperative navigation, however, is challenged by increased surgical time and additional technically difficult steps. Patient-matched instrumentation has the potential to reproduce a similar degree of accuracy without the need for additional surgical steps. The purpose of this study was to examine the accuracy of patient-specific planning and a patient-specific drill guide for glenoid baseplate placement in reverse shoulder arthroplasty. A patient-specific glenoid baseplate drill guide for reverse shoulder arthroplasty was produced for 14 cadaveric shoulders based on a plan developed by a virtual preoperative 3-dimensional planning system using thin-cut computed tomography images. Using this patient-specific guide, high-volume shoulder surgeons exposed the glenoid through a deltopectoral approach and drilled the bicortical pathway defined by the guide. The trajectory of the drill path was compared with the virtual preoperative planned position using similar thin-cut computed tomography images to define accuracy. The drill pathway defined by the patient-matched guide was found to be highly accurate when compared with the preoperative surgical plan. The translational accuracy was 1.2 ± 0.7 mm. The accuracy of inferior tilt was 1.2° ± 1.2°. The accuracy of glenoid version was 2.6° ± 1.7°. The use of patient-specific glenoid baseplate guides is highly accurate in reproducing a virtual 3-dimensional preoperative plan. This technique delivers the accuracy observed using computerized navigation without any additional surgical steps or technical challenges. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

30 CFR 250.1617 - Application for permit to drill.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Formation fracture gradients; (iii) Potential lost circulation zones; (iv) Mud weights; (v) Casing setting... various casing strings, fracture gradients of the exposed formations, casing setting depths, and cementing...

30 CFR 250.1617 - Application for permit to drill.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Formation fracture gradients; (iii) Potential lost circulation zones; (iv) Mud weights; (v) Casing setting... various casing strings, fracture gradients of the exposed formations, casing setting depths, and cementing...

30 CFR 250.1617 - Application for permit to drill.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Formation fracture gradients; (iii) Potential lost circulation zones; (iv) Mud weights; (v) Casing setting... various casing strings, fracture gradients of the exposed formations, casing setting depths, and cementing...

Geologic and geophysical data for wells drilled at Raft River Valley, Cassia County, Idaho, in 1977-1978 and data for wells drilled previously

USGS Publications Warehouse

Nathenson, Manuel; Urban, Thomas C.; Covington, Harry R.

2014-01-01

For purposes of defining the thermal anomaly for the geothermal system, temperature gradients are calculated over long depth intervals on the basis of the appearance of reasonable linear segments on a temperature versus plot depth.  Temperature versus depth data for some drill holes can be represented by a single gradient, whereas others require multiple gradients to match the data.  Data for some drill holes clearly reflect vertical flows of water in the formation surrounding the drill holes, and water velocities are calculated for these drill holes.  Within The Narrows area, temperature versus depth data show reversals at different depth in different drill holes.  In the main thermal area, temperatures in intermediate-depth drill holes vary approximately linearly but with very high values of temperature gradient.  Temperature gradients on a map of the area can be reasonable divided into a large area of regional gradients and smaller areas defining the thermal anomalies.

Mechanisms underlying recent decadal changes in subpolar North Atlantic Ocean heat content

NASA Astrophysics Data System (ADS)

Piecuch, Christopher G.; Ponte, Rui M.; Little, Christopher M.; Buckley, Martha W.; Fukumori, Ichiro

2017-09-01

The subpolar North Atlantic (SPNA) is subject to strong decadal variability, with implications for surface climate and its predictability. In 2004-2005, SPNA decadal upper ocean and sea-surface temperature trends reversed from warming during 1994-2004 to cooling over 2005-2015. This recent decadal trend reversal in SPNA ocean heat content (OHC) is studied using a physically consistent, observationally constrained global ocean state estimate covering 1992-2015. The estimate's physical consistency facilitates quantitative causal attribution of ocean variations. Closed heat budget diagnostics reveal that the SPNA OHC trend reversal is the result of heat advection by midlatitude ocean circulation. Kinematic decompositions reveal that changes in the deep and intermediate vertical overturning circulation cannot account for the trend reversal, but rather ocean heat transports by horizontal gyre circulations render the primary contributions. The shift in horizontal gyre advection reflects anomalous circulation acting on the mean temperature gradients. Maximum covariance analysis (MCA) reveals strong covariation between the anomalous horizontal gyre circulation and variations in the local wind stress curl, suggestive of a Sverdrup response. Results have implications for decadal predictability.

The Effect of Pitching Phase on the Vortex Circulation for a Flapping Wing During Stroke Reversal

NASA Astrophysics Data System (ADS)

Burge, Matthew; Ringuette, Matthew

2017-11-01

We study the effect of pitching-phase on the circulation behavior for the 3D flow structures produced during stroke reversal for a 2-degree-of-freedom flapping wing executing hovering kinematics. Previous research has related the choice in pitching-phase with respect to the wing rotation during stroke reversal (advanced vs. symmetric pitch-timing) to a lift peak preceding stroke reversal. However, results from experiments on the time-varying circulation contributions from the 3D vortex structures across the span produced by both rotation and pitching are lacking. The objective of this research is to quantitatively examine how the spanwise circulation of these structures is affected by the pitching-phase for several reduced pitching frequencies. We employ a scaled wing model in a glycerin-water mixture and measure the time-varying velocity using multiple planes of stereo digital particle image velocimetry. Data-plane positions along the wing span are informed by the unsteady behavior of the 3D vortex structures found in our prior flow visualization movies. Individual vortices are identified to calculate their circulation. This work is aimed at understanding how the behavior of the vortex structures created during stroke reversal vary with key motion parameters. This work is supported by the National Science Foundation, Award Number 1336548, supervised by Dr. Ronald Joslin.

Facility for testing ice drills

NASA Astrophysics Data System (ADS)

Nielson, Dennis L.; Delahunty, Chris; Goodge, John W.; Severinghaus, Jeffery P.

2017-05-01

The Rapid Access Ice Drill (RAID) is designed for subsurface scientific investigations in Antarctica. Its objectives are to drill rapidly through ice, to core samples of the transition zone and bedrock, and to leave behind a borehole observatory. These objectives required the engineering and fabrication of an entirely new drilling system that included a modified mining-style coring rig, a unique fluid circulation system, a rod skid, a power unit, and a workshop with areas for the storage of supplies and consumables. An important milestone in fabrication of the RAID was the construction of a North American Test (NAT) facility where we were able to test drilling and fluid processing functions in an environment that is as close as possible to that expected in Antarctica. Our criteria for site selection was that the area should be cold during the winter months, be located in an area of low heat flow, and be at relatively high elevation. We selected a site for the facility near Bear Lake, Utah, USA. The general design of the NAT well (NAT-1) started with a 27.3 cm (10.75 in.) outer casing cemented in a 152 m deep hole. Within that casing, we hung a 14 cm (5.5 in.) casing string, and, within that casing, a column of ice was formed. The annulus between the 14 and 27.3 cm casings provided the path for circulation of a refrigerant. After in-depth study, we chose to use liquid CO2 to cool the hole. In order to minimize the likelihood of the casing splitting due to the volume increase associated with freezing water, the hole was first cooled and then ice was formed in increments from the bottom upward. First, ice cubes were placed in the inner liner and then water was added. Using this method, a column of ice was incrementally prepared for drilling tests. The drilling tests successfully demonstrated the functioning of the RAID system. Reproducing such a facility for testing of other ice drilling systems could be advantageous to other research programs in the future.

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2011 CFR

2011-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... oil contamination in drilling fluids. 1.4This method has been designed to show positive contamination....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

Using a global ocean circulation model to conduct a preliminary risk assessment of oil spills in the Atlantic

NASA Astrophysics Data System (ADS)

Jacobs, Zoe; Popova, Katya; Hirschi, Joel; Coward, Andrew; Yool, Andrew; van Gennip, Simon; Anifowose, Babtunde; Harrington-Missin, Liam

2017-04-01

Although oil blowouts from deep-water drilling happen very rarely, they can cause catastrophic damage to the environment. Despite such potentially high impacts, relatively little research effort has gone into understanding subsurface oil plumes in the deep ocean. In this study, we demonstrate the significance of this problem and offer potential solutions using a novel approach based on a leading-edge, high-resolution global ocean circulation model. We present examples demonstrating: (a) the importance of ocean circulation in the propagation of oil spills; and (b) likely circulation footprints for oil spills at four key locations in the Atlantic Ocean that exist in different circulation regimes - the shelves of Brazil, the Gulf of Guinea, the Gulf of Mexico and the Faroe-Shetland Channel. In order to quantify the variability at each site on seasonal timescales, interannual timescales and at different depths, we utilize the Modified Hausdorff Distance (MHD), which is a shape-distance metric that measures the similarity between two shapes. The scale of the footprints across the four focus locations varies considerably and is determined by the main circulation features in their vicinity. For example, the hypothetical oil plume can be affected by variations in the speed and location of a particular current (e.g. Brazil Current at the Brazilian shelf site) or be influenced by different currents entirely depending on the release depth, month and year (e.g. Angola Current or Southern Equatorial Current at the Gulf of Guinea site). Overall, our results demonstrate the need to use state of the art global, or basin-scale, ocean circulation models when assessing the environmental impacts of proposed oil drilling activities.

Problems of deep drilling in abnormally pressured zones of the Kara Sea continental shelf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simonov, V.I.

1996-12-31

There are discussed results of drilling operations in shelf hydrocarbon areas of the Far North of Tyumen Region (Kharassavieskaya, Bovanenkovskaya and Krusenshternskaya ones) and on the Bely Island. The author describes equipment and technologies used, problems arising in the process of operations and possible ways of solving them. Application of the results discussed in the report seems rather attractive in connection with possible realization of joint projects on development of the mentioned areas. Thus, Amoco Eurasia plans to participate in development of Bovanenkovskoye and Novoportovskoye fields. Well planning for Amoco has been done of specialists of ZapSibBurNIPI. Experience of Russianmore » drilling companies in the Yamal area (Far North of Tyumen Region) has proved that well planning for shelf areas requires special attention as drilling-in both overpressured zones (Bovanenkovskoye field) and underpressured ones (Novoportovskoye field) is done actually in balance. Investigated are reasons for such drilling problems as kicks and lost circulation. Taking them into consideration will help to decrease considerably the cost of well drilling in shelf areas.« less

Wellbore stability analysis and its application in the Fergana basin, central Asia

NASA Astrophysics Data System (ADS)

Chuanliang, Yan; Jingen, Deng; Baohua, Yu; Hailong, Liu; Fucheng, Deng; Zijian, Chen; Lianbo, Hu; Haiyan, Zhu; Qin, Han

2014-02-01

Wellbore instability is one of the major problems hampering the drilling speed in the Fergana basin. Comprehensive analysis of the geological and engineering data in this area indicates that the Fergana basin is characterized by high in situ stress and plenty of natural fractures, especially in the formations which are rich in bedding structure and have several high-pressure systems. Complex accidents such as wellbore collapse, sticking, well kick and lost circulation happen frequently. Tests and theoretical analysis reveals that the wellbore instability in the Fergana basin was influenced by multiple interactive mechanisms dominated by the instability of the bedding shale. Selecting a proper drilling fluid density and improving the sealing characteristic of the applied drilling fluid is the key to preventing wellbore instability in the Fergana basin. The mechanical mechanism of wellbore instability in the Fergana basin was analysed and a method to determine the proper drilling fluid density was proposed. The research results were successfully used to guide the drilling work of the Jida-4 well; compared with the Jida-3 well, the drilling cycle of the Jida-4 well was reduced by 32%.

Rowan Gorilla I rigged up, heads for eastern Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1984-03-01

Designed to operate in very hostile offshore environments, the first of the Rowan Gorilla class of self-elevating drilling rigs has been towed to its drilling assignment offshore Nova Scotia. About 40% larger than other jackups, these rigs can operate in 300 ft of water, drilling holes as deep as 30,000 ft. They also feature unique high-pressure and solids control systems that are expected to improve drilling procedures and efficiencies. A quantitative formation pressure evaluation program for the Hewlett-Packard HP-41 handheld calculator computes formation pressures by three independent methods - the corrected d exponent, Bourgoyne and Young, and normalized penetration ratemore » techniques for abnormal pressure detection and computation. Based on empirically derived drilling rate equations, each of the methods can be calculated separately, without being dependent on or influenced by the results or stored data from the other two subprograms. The quantitative interpretation procedure involves establishing a normal drilling rate trend and calculating the pore pressure from the magnitude of the drilling rate trend or plotting parameter increases above the trend line. Mobil's quick, accurate program could aid drilling operators in selecting the casing point, minimizing differential sticking, maintaining the proper mud weights to avoid kicks and lost circulation, and maximizing penetration rates.« less

Investigating Created Properties of Nanoparticles Based Drilling Mud

NASA Astrophysics Data System (ADS)

Ghasemi, Nahid; Mirzaee, Mojtaba; Aghayari, Reza; Maddah, Heydar

2018-05-01

The success of drilling operations is heavily dependent on the drilling fluid. Drilling fluids cool down and lubricate the drill bit, remove cuttings, prevent formation damage, suspend cuttings and also cake off the permeable formation, thus retarding the passage of fluid into the formation. Typical micro or macro sized loss circulation materials (LCM) show limited success, especially in formations dominated by micropores, due to their relatively large sizes. Due to unique characteristics of nanoparticles such as their size and high surface area to volume ratio, they play an effective role in solving problems associated with the drilling fluid. In this study, we investigate the effect of adding Al2O3 and TiO2 nanoparticles into the drilling mud. Al2O3 and TiO2 nanoparticles were used in 20 and 60 nm of size and 0.05 wt% in concentration. Investigating the effects of temperature and pressure has shown that an increase in temperature can reduce the drilling mud rheological properties such as plastic viscosity, while an increase in pressure can enhance these properties. Also, the effects of pressure in high temperatures were less than those in low temperatures. Studying the effects of adding nanoparticles has shown that they can reduce the drilling mud rheological properties. Moreover, they can increase gel strength, reduce capillary suction time and decrease formation damage.

On the Freshwater Sensitivity of the Arctic-Atlantic Thermohaline Circulation

NASA Astrophysics Data System (ADS)

Lambert, E.; Eldevik, T.; Haugan, P.

2016-02-01

The North Atlantic thermohaline circulation (THC) carries heat and salt toward the Arctic. This circulation is generally believed to be inhibited by northern freshwater input as indicated by the `box-model' of Stommel (1961). The inferred freshwater-sensitivity of the THC, however, varies considerably between studies, both quantitatively and qualitatively. The northernmost branch of the Atlantic THC, which forms a double estuarine circulation in the Arctic Mediterranean, is one example where both strengthening and weakening of the circulation may occur due to increased freshwater input. We have accordingly built on Stommel's original concept to accomodate a THC similar to that in the Arctic Mediterranean. This model consists of three idealized basins, or boxes, connected by two coupled branches of circulation - the double estuary. The net transport of these two branches represents the extension of the Gulf Stream toward the Arctic. Its sensitivity to a change in freshwater forcing depends largely on the distribution of freshwater over the two northern basins. Varying this distribution opens a spectrum of qualitative behaviours ranging from Stommel's original freshwater-inhibited overturning circulation to a freshwater-facilitated estuarine circulation. Between these limiting cases, a Hopf and a cusp bifurcation divide the spectrum into three qualitative regions. In the first region, the circulation behaves similarly to Stommel's circulation, and sufficient freshwater input can induce an abrupt transition into a reversed flow; in the second, a similar transition can be found, although it does not reverse the circulation; in the third, no transition can occur and the circulation is generally facilitated by the northern freshwater input. Overall, the northern THC appears more stable than what would be inferred based on Stommel's model; it requires a larger amount and more localized freshwater input to `collapse' it, and a double estuary circulation is less prone to flow reversal.

Elemental composition of airborne dust in the Shale Shaker House during an offshore drilling operation.

PubMed

Hansen, A B; Larsen, E; Hansen, L V; Lyngsaae, M; Kunze, H

1991-12-01

During 2 days of an offshore drilling operation in the North Sea, 16 airborne dust samples from the atmosphere of the Shale Shaker House were collected onto filters. During this operation, drilling mud composed of a water slurry of barite (BaSO4) together with minor amounts of additives, among them chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively coupled plasma-mass spectrometry). The total amount of dust collected varied from 0.04 to 1.41 mg m-3 with barium (Ba) as the single most abundant element. The open shale shakers turned out to be the major cause of generation of dust from the solid components of the drilling mud.

Phase 1 drilling operations at the Magma Energy Exploratory Well (LVF 51-20)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finger, J.T.; Jacobson, R.D.

1990-12-01

This report describes the Phase 1 drilling operations for the Magma Energy Exploratory Well near Mammoth Lakes, California. An important part of the Department of Energy's Magma Energy Program, this well is designed to reach an ultimate depth of 20,000 feet or a bottomhole temperature of 500{degree}C, whichever comes first. There will be four drilling phases, at least a year apart, with scientific investigations in the borehole between the drilling intervals. Phase 1 of this project resulted in a 20 inch cased hole to 2558 feet, with 185 feet of coring beyond that. This document comprises a narrative of themore » daily activities, copies of the daily mud and lithologic reports, time breakdowns of rig activities, inventories of lost circulation materials, temperature logs of the cored hole, and a strip chart mud log. 2 figs.« less

Independent Technical Investigation of the Puna Geothermal Venture Unplanned Steam Release, June 12 and 13, 1991, Puna, Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Richard; Whiting, Dick; Moore, James

1991-07-01

On June 24, 1991, a third-party investigation team consisting of Richard P. Thomas, Duey E. Milner, James L. Moore, and Dick Whiting began an investigation into the blowout of well KS-8, which occurred at the Puna Geothermal Venture (PGV) site on June 12, 1991, and caused the unabated release of steam for a period of 31 hours before PGV succeeded in closing in the well. The scope of the investigation was to: (a) determine the cause(s) of the incident; (b) evaluate the adequacy of PGVs drilling and blowout prevention equipment and procedures; and (c) make recommendations for any appropriate changesmore » in equipment and/or procedures. This report finds that the blowout occurred because of inadequacies in PGVs drilling plan and procedures and not as a result of unusual or unmanageable subsurface geologic or hydrologic conditions. While the geothermal resource in the area being drilled is relatively hot, the temperatures are not excessive for modem technology and methods to control. Fluid pressures encountered are also manageable if proper procedures are followed and the appropriate equipment is utilized. A previous blowout of short duration occurred on February 21, 1991, at the KS-7 injection well being drilled by PGV at a depth of approximately 1600'. This unexpected incident alerted PGV to the possibility of encountering a high temperature, fractured zone at a relatively shallow depth. The experience at KS-7 prompted PGV to refine its hydrological model; however, the drilling plan utilized for KS-8 was not changed. Not only did PGV fail to modify its drilling program following the KS-7 blowout, but they also failed to heed numerous ''red flags'' (warning signals) in the five days preceding the KS-8 blowout, which included a continuous 1-inch flow of drilling mud out of the wellbore, gains in mud volume while pulling stands, and gas entries while circulating muds bottoms up, in addition to lost circulation that had occurred earlier below the shoe of the 13-3/8-hch casing.« less

Ocean Drilling: Forty Years of International Collaboration

NASA Astrophysics Data System (ADS)

Smith, Deborah K.; Exon, Neville; Barriga, Fernando J. A. S.; Tatsumi, Yoshiyuki

2010-10-01

International cooperation is an essential component of modern scientific research and societal advancement [see Ismail-Zadeh and Beer, 2009], and scientific ocean drilling represents one of Earth science's longest-running and most successful international collaborations. The strength of this collaboration and its continued success result from the realization that scientific ocean drilling provides a unique and powerful tool to study the critical processes of both short-term change and the long-term evolution of Earth systems. A record of Earth's changing tectonics, climate, ocean circulation, and biota is preserved in marine sedimentary deposits and the underlying basement rocks. And because the ocean floor is the natural site for accumulation and preservation of geological materials, it may preserve a continuous record of these processes.

Continuous chain bit with downhole cycling capability

DOEpatents

Ritter, Don F.; St. Clair, Jack A.; Togami, Henry K.

1983-01-01

A continuous chain bit for hard rock drilling is capable of downhole cycling. A drill head assembly moves axially relative to a support body while the chain on the head assembly is held in position so that the bodily movement of the chain cycles the chain to present new composite links for drilling. A pair of spring fingers on opposite sides of the chain hold the chain against movement. The chain is held in tension by a spring-biased tensioning bar. A head at the working end of the chain supports the working links. The chain is centered by a reversing pawl and piston actuated by the pressure of the drilling mud. Detent pins lock the head assembly with respect to the support body and are also operated by the drilling mud pressure. A restricted nozzle with a divergent outlet sprays drilling mud into the cavity to remove debris. Indication of the centered position of the chain is provided by noting a low pressure reading indicating proper alignment of drilling mud slots on the links with the corresponding feed branches.

Superhot Drilling in Iceland, the Experience of the Iceland Deep Drilling Project.

NASA Astrophysics Data System (ADS)

Elders, W. A.; Friðleifsson, G. Ó.; Zierenberg, R. A.; Fowler, A. P.

2017-12-01

The Iceland Deep Drilling Project aims to improve geothermal economics by producing supercritical fluids (www.iddp.is). Supercritical wells could yield an order of magnitude more usable energy than that from conventional geothermal wells because of higher enthalpy and enhanced flow properties. In 2009, the IDDP-1 well failed to reach supercritical conditions in the Krafla caldera in NE Iceland, after encountering rhyolite magma at only 2.1 km depth. The completed geothermal well became the world's hottest and produced superheated steam with a wellhead temperature of 452°C and flow sufficient to generate 35 MWe. The IDDP next moved SW to the Reykjanes Peninsula, the landward extension of the Mid-Atlantic Ridge, where it is possible to study an analog of the roots of a black smoker. Reykjanes is unique among Icelandic geothermal systems in being recharged by seawater, which has a critical point of 406°C at 298 bars. Drilling began by deepening an existing 2.5 km deep production well to 3 km depth, and then angling it towards the main upflow zone of the system, for a total slant depth of 4,659 m. Total circulation losses were encountered below 3 km that could not be cured by lost circulation materials or by multiple cement jobs. Accordingly, drilling continued to total depth without return of drill cuttings. We attempted 13 core runs below 3 km depth, only half of which recovered core. The cores are basalts and dolerites with alteration ranging from lower greenschist facies to lower amphibolite facies, suggesting formation temperatures >450°C. After the end of drilling in January 2017, following only six days of heating, supercritical conditions (426°C at 340 bars) were measured in the well at a depth of 4.5 km. The well has not yet been allowed to equilibrate to full in situ temperature. A perforated liner was inserted to 4,570 m, depth to facilitate temperature cycling to enhance permeability at depth through thermal cracking. In 2018 this will be followed by a flow test and eventual production of the well. The project is co-funded by the DEEPEGS project (EU H2020), HS Orka (the field operator), Statoil, the IDDP consortium, and the ICDP. Planning is underway to drill IDDP-3 at Hellisheidi.

High-pressure high-temperature rheological studies of colloidal suspensions with carbon nanotube

NASA Astrophysics Data System (ADS)

Baby, Anoop; Sadr, Reza; Yarc, Rommel; Amani, Mahmood

2017-11-01

Selection of the drilling fluid, drilling mud, is vital in minimizing the cost and time required for the drilling in oil fields. Drilling mud aids in cooling, lubricating drilling bit, removing the debries from the drill bore and maintaining the wellbore stability. Owing to the enhanced thermo-physical properties and stable nature, suspensions of nanoparticles have been suggested for drilling fluids. High-pressure and high-temperature rheology of a nanomud suspension (nano particles suspended in a mud solution) is studied here. The nanomud is prepared by dispersing a water-based drilling mud suspension (water with 1% Bentonite and 7% Barite particles) with multi-walled carbon nanotubes, MWCNT. The effect of pressure, temperature, and shear rate are independently studied for the various particle loading of the nanoparticles. Viscosity values are measured at a maximum pressure of 170MPa with temperatures ranging from ambient to 180oC. The effect of MWCNT concentration and variation in shear rate are also investigated A shear thinning non-Newtonian behavior is observed for the basemud and the nanomud samples for all cases. The basemud showed an increase in viscosity with an increase in pressure. However, with MWCNT particle addition, this trend is observed to have reversed.

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2010 CFR

2010-07-01

... environment and a current awareness file of OSHA regulations regarding the safe handling of the chemicals... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Reverse Phase Extraction (RPE) Method... Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND...

Nd isotopic structure of the Pacific Ocean 70-30 Ma and numerical evidence for vigorous ocean circulation and ocean heat transport in a greenhouse world

NASA Astrophysics Data System (ADS)

Thomas, Deborah J.; Korty, Robert; Huber, Matthew; Schubert, Jessica A.; Haines, Brian

2014-05-01

The oceanic meridional overturning circulation (MOC) is a crucial component of the climate system, impacting heat and nutrient transport, and global carbon cycling. Past greenhouse climate intervals present a paradox because their weak equator-to-pole temperature gradients imply a weaker MOC, yet increased poleward oceanic heat transport appears to be required to maintain these weak gradients. To investigate the mode of MOC that operated during the early Cenozoic, we compare new Nd isotope data with Nd tracer-enabled numerical ocean circulation and coupled climate model simulations. Assimilation of new Nd isotope data from South Pacific Deep Sea Drilling Project and Ocean Drilling Program Sites 323, 463, 596, 865, and 869 with previously published data confirm the hypothesized MOC characterized by vigorous sinking in the South and North Pacific 70 to 30 Ma. Compilation of all Pacific Nd isotope data indicates vigorous, distinct, and separate overturning circulations in each basin until 40 Ma. Simulations consistently reproduce South Pacific and North Pacific deep convection over a broad range of conditions, but cases using strong deep ocean vertical mixing produced the best data-model match. Strong mixing, potentially resulting from enhanced abyssal tidal dissipation, greater interaction of wind-driven internal wave activity with submarine plateaus, or higher than modern values of the geothermal heat flux enable models to achieve enhanced MOC circulation rates with resulting Nd isotope distributions consistent with the proxy data. The consequent poleward heat transport may resolve the paradox of warmer worlds with reduced temperature gradients.

Disposal of saltwater during well construction--Problems and solutions

USGS Publications Warehouse

Pitt, William A.; Meyer, Frederick W.; Hull, John E.

1977-01-01

The recent interest in the disposal of treated sewage effluent by deep-well injection into salt-water-filled aquifers has increased the need for proper disposal of salt water as more wells are drilled and tested each year.The effects on an unconfined aquifer of the improper disposal of salt water associated with the construction of three wells in southeastern Florida emphasize this need. In two of the wells provisions to prevent and detect salt-water contamination of the unconfined aquifer were practically nonexistent, and in one well extensive provisions were made. Of the three drilling sites the one with proper provision for detection presented no serious problem, as the ground water contaminated by the salt water was easily located and removed. The provisions consisted of drilling a brine-injection well to dispose of salt water discharged in drilling and testing operations, using a closed drilling circulation system to reduce spillage, installing shallow observation wells to map the extent and depth of any salt-water contamination of the shallow aquifer, and installing a dewatering system to remove contaminated ground water.

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, T.R.

1983-07-05

A method and a cutter are disclosed for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head has a hollow body with a generally circular base and sloping upper surface. A hollow shaft extends from the hollow body. Cutter teeth are mounted on the upper surface of the body and relatively small holes are formed in the body between the cutter teeth. Relatively large peripheral flutes around the body allow material to drop below the drill head. A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale. 4 figs.

A Comprehensive Prediction Model of Hydraulic Extended-Reach Limit Considering the Allowable Range of Drilling Fluid Flow Rate in Horizontal Drilling.

PubMed

Li, Xin; Gao, Deli; Chen, Xuyue

2017-06-08

Hydraulic extended-reach limit (HERL) model of horizontal extended-reach well (ERW) can predict the maximum measured depth (MMD) of the horizontal ERW. The HERL refers to the well's MMD when drilling fluid cannot be normally circulated by drilling pump. Previous model analyzed the following two constraint conditions, drilling pump rated pressure and rated power. However, effects of the allowable range of drilling fluid flow rate (Q min  ≤ Q ≤ Q max ) were not considered. In this study, three cases of HERL model are proposed according to the relationship between allowable range of drilling fluid flow rate and rated flow rate of drilling pump (Q r ). A horizontal ERW is analyzed to predict its HERL, especially its horizontal-section limit (L h ). Results show that when Q min  ≤ Q r  ≤ Q max (Case I), L h depends both on horizontal-section limit based on rated pump pressure (L h1 ) and horizontal-section limit based on rated pump power (L h2 ); when Q min  < Q max  < Q r (Case II), L h is exclusively controlled by L h1 ; while L h is only determined by L h2 when Q r  < Q min  < Q max (Case III). Furthermore, L h1 first increases and then decreases with the increase in drilling fluid flow rate, while L h2 keeps decreasing as the drilling fluid flow rate increases. The comprehensive model provides a more accurate prediction on HERL.

Localization, characterization and dating of water circulations in the soil-saprolite system of the Strengbach watershed: petrological, hydro-geophysical and geochemical evidences.

NASA Astrophysics Data System (ADS)

Chabaux, François; Viville, Daniel; Pierret, Marie-Claire; Stille, Peter; Lerouge, Catherine; Wyns, Robert; Dezayes, Chrystel; Labasque, Thierry; Aquilina, Luc; Ranchoux, Coralie; Négrel, Philippe

2017-04-01

The characterization of the critical zone along depth profiles remains a major scientific issue for understanding and modelling the response of continental surfaces to climatic, tectonic and anthropogenic forcings. Besides characterization it requires the modelling of the water circulations within the substratum of the critical zone. A series of boreholes drilled along the north and the south slopes of the Strengbach watershed makes it possible to characterize the critical zone to depths of ≈100 to 150 m within this critical zone observatory. In this study we attempt to combine mineralogical and petrological observations of the cores recovered through the drilling with chemical data of waters collected in each of these wells and hydro-geophysical data in order to characterize processes of water-rock interactions, visualize the water arrivals within the boreholes and bring new information on the deep water circulations within the watershed. Mineralogical, petrological and hydrogeophysical data suggest that deepwater circulation in the watershed likely occurs along fractures, concentrated in relatively narrow areas, several centimeters wide, interspersed with areas where the granite is much less fractured. This points to the occurrence of deep waters circulating in a network of more or less independent conduits, which could extend over several tens to hundreds of meters deep. The hydrochemical data from the boreholes, show contrasting characteristics for surface waters collected at 10 to 15 m depth and the deeper waters collected between 50 to 80m depth; the surface waters are very similar to those of the spring waters collected in the watershed (Pierret et al., 2014), and the deeper waters collected between 50 to 80m depth. The residence times of the circulating waters are also very variable, with ages of up to a few months for surface and subsurface waters and ages exceeding several decades for the deep waters. These differences suggest that the subsurface circulation systems are quite different from the deeper circulation ones. They also point to the importance to focus future studies on deep-water circulations in order to properly characterize the functioning of the critical zone in watersheds, especially in mountainous areas, such as the Strengbach watershed.

36 CFR 9.36 - Plan of operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and characteristics of the proposed circulating medium or mediums to be employed for rotary drilling... regulations; (16) Background information, including: (i) A description of the natural, cultural, social and... indirect effects of the operations on the unit's natural, cultural, social, and economic environment; (iii...

36 CFR 9.36 - Plan of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and characteristics of the proposed circulating medium or mediums to be employed for rotary drilling... regulations; (16) Background information, including: (i) A description of the natural, cultural, social and... indirect effects of the operations on the unit's natural, cultural, social, and economic environment; (iii...

36 CFR 9.36 - Plan of operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and characteristics of the proposed circulating medium or mediums to be employed for rotary drilling... regulations; (16) Background information, including: (i) A description of the natural, cultural, social and... indirect effects of the operations on the unit's natural, cultural, social, and economic environment; (iii...

36 CFR 9.36 - Plan of operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and characteristics of the proposed circulating medium or mediums to be employed for rotary drilling... regulations; (16) Background information, including: (i) A description of the natural, cultural, social and... indirect effects of the operations on the unit's natural, cultural, social, and economic environment; (iii...

36 CFR 9.36 - Plan of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and characteristics of the proposed circulating medium or mediums to be employed for rotary drilling... regulations; (16) Background information, including: (i) A description of the natural, cultural, social and... indirect effects of the operations on the unit's natural, cultural, social, and economic environment; (iii...

Offshore wellbore stability analysis based on fully coupled poro-thermo-elastic theory

NASA Astrophysics Data System (ADS)

Cao, Wenke; Deng, Jingen; Yu, Baohua; Liu, Wei; Tan, Qiang

2017-03-01

Drilling-induced tensile fractures are usually caused when the weight of mud is too high, and the effective tangential stress becomes tensile. It is thus hard to explain why tensile fractures are distributed along the lower part of a hole in an offshore exploration well when the mud weight is low. According to analysis, the reason could be the thermal effect, which cannot be ignored because of the drilling fluid and the cooling action of sea water during circulation. A heat transfer model is set up to obtain the temperature distribution of the wellbore and its formation by the finite difference method. Then, fully coupled poro-thermo-elastic theory is used to study the pore pressure and effective stress around the wellbore. By comparing it with both poroelastic and elastic models, it is indicated that the poroelastic effect is dominant at the beginning of circulation and inhibits tensile fractures from forming; then, the thermal effect becomes more important and decreases the effective tangential stress with the passing of time, so the drilling fluid and the cooling effect of sea water can cause tensile fractures to happen. Meanwhile, tensile fractures are shallow and not likely to lead to mud leakage with lower mud weight, which agrees with the actual drilling process. On the other hand, the fluid cooling effect could increase the strength of the rock and reduce the likelihood of shear failure, which would be beneficial for wellbore stability. So, the thermal effect cannot be neglected in offshore wellbore stability analysis, and mud weight and borehole exposure time should be controlled in the case of mud loss.

Optimizing Geothermal Drilling: Oil and Gas Technology Transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denninger, Kate; Eustes, Alfred; Visser, Charles

There is a significant amount of financial risk associated with geothermal drilling. This study of drilling operations seeks opportunities to improve upon current practices and technologies. The scope of this study included analyzing 21 geothermal wells and 21 oil and gas wells. The goal was to determine a 'Perfect Well' using historical data to compare the best oil and gas well to the best geothermal well. Unfortunately, limitations encountered in the study included missing data (bit records, mud information, etc.) and poor data collection practices An online software database was used to format drilling data to IADC coded daily drillingmore » reports and generate figures for analysis. Six major issues have been found in geothermal drilling operations. These problems include lost circulation, rig/ equipment selection, cementing, penetration rate, drilling program, and time management. As a result of these issues, geothermal drilling averaged 56.4 days longer than drilling comparable oil and gas wells in the wells in this study. Roughly $13.9 million was spent on non-productive time in the 21 geothermal wells, compared with only $1.3 million in the oil and gas wells, assuming a cost of $50,000 per day. Comparable events such as drilling the same sized hole, tripping in/out, cementing, and running the same size casing took substantially less time in the oil and gas wells. Geothermal wells were drilled using older and/or less advanced technology to depths less than 10,000 feet, while oil and gas wells reached 12,500 feet faster with purpose built rigs. A new approach is now underway that will optimize drilling programs throughout the drilling industry using Mechanical Specific Energy (MSE) as a tool to realize efficient drilling processes. Potential improvements for current geothermal operations are: the use of electronic records, real time services, and official glossary terms to describe rig operations, and advanced drilling rigs/technology.« less

Antarctic climate, Southern Ocean circulation patterns, and deep water formation during the Eocene

NASA Astrophysics Data System (ADS)

Huck, Claire E.; van de Flierdt, Tina; Bohaty, Steven M.; Hammond, Samantha J.

2017-07-01

We assess early-to-middle Eocene seawater neodymium (Nd) isotope records from seven Southern Ocean deep-sea drill sites to evaluate the role of Southern Ocean circulation in long-term Cenozoic climate change. Our study sites are strategically located on either side of the Tasman Gateway and are positioned at a range of shallow (<500 m) to intermediate/deep ( 1000-2500 m) paleowater depths. Unradiogenic seawater Nd isotopic compositions, reconstructed from fish teeth at intermediate/deep Indian Ocean pelagic sites (Ocean Drilling Program (ODP) Sites 738 and 757 and Deep Sea Drilling Project (DSDP) Site 264), indicate a dominant Southern Ocean-sourced contribution to regional deep waters (ɛNd(t) = -9.3 ± 1.5). IODP Site U1356 off the coast of Adélie Land, a locus of modern-day Antarctic Bottom Water production, is identified as a site of persistent deep water formation from the early Eocene to the Oligocene. East of the Tasman Gateway an additional local source of intermediate/deep water formation is inferred at ODP Site 277 in the SW Pacific Ocean (ɛNd(t) = -8.7 ± 1.5). Antarctic-proximal shelf sites (ODP Site 1171 and Site U1356) reveal a pronounced erosional event between 49 and 48 Ma, manifested by 2 ɛNd unit negative excursions in seawater chemistry toward the composition of bulk sediments at these sites. This erosional event coincides with the termination of peak global warmth following the Early Eocene Climatic Optimum and is associated with documented cooling across the study region and increased export of Antarctic deep waters, highlighting the complexity and importance of Southern Ocean circulation in the greenhouse climate of the Eocene.

Paleoceanography. Onset of Mediterranean outflow into the North Atlantic.

PubMed

Hernández-Molina, F Javier; Stow, Dorrik A V; Alvarez-Zarikian, Carlos A; Acton, Gary; Bahr, André; Balestra, Barbara; Ducassou, Emmanuelle; Flood, Roger; Flores, José-Abel; Furota, Satoshi; Grunert, Patrick; Hodell, David; Jimenez-Espejo, Francisco; Kim, Jin Kyoung; Krissek, Lawrence; Kuroda, Junichiro; Li, Baohua; Llave, Estefania; Lofi, Johanna; Lourens, Lucas; Miller, Madeline; Nanayama, Futoshi; Nishida, Naohisa; Richter, Carl; Roque, Cristina; Pereira, Hélder; Sanchez Goñi, Maria Fernanda; Sierro, Francisco J; Singh, Arun Deo; Sloss, Craig; Takashimizu, Yasuhiro; Tzanova, Alexandrina; Voelker, Antje; Williams, Trevor; Xuan, Chuang

2014-06-13

Sediments cored along the southwestern Iberian margin during Integrated Ocean Drilling Program Expedition 339 provide constraints on Mediterranean Outflow Water (MOW) circulation patterns from the Pliocene epoch to the present day. After the Strait of Gibraltar opened (5.33 million years ago), a limited volume of MOW entered the Atlantic. Depositional hiatuses indicate erosion by bottom currents related to higher volumes of MOW circulating into the North Atlantic, beginning in the late Pliocene. The hiatuses coincide with regional tectonic events and changes in global thermohaline circulation (THC). This suggests that MOW influenced Atlantic Meridional Overturning Circulation (AMOC), THC, and climatic shifts by contributing a component of warm, saline water to northern latitudes while in turn being influenced by plate tectonics. Copyright © 2014, American Association for the Advancement of Science.

Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

PubMed

Moran, Anthony R; Hettiarachchi, Hiroshan

2011-07-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

PubMed Central

Moran, Anthony R.; Hettiarachchi, Hiroshan

2011-01-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

Optimizing Geothermal Drilling: Oil and Gas Technology Transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tilley, Mitch; Eustes, Alfred; Visser, Charles

There is a significant amount of financial risk associated with geothermal drilling; however, there are opportunities to improve upon current practices and technologies used. The scope of this drilling operational study included 21 geothermal wells and 21 oil and gas wells. The goal was to determine a 'perfect well' using historical data to compare the best oil and gas well to the best geothermal well. Unfortunately, limitations encountered in the study included missing data (bit records, mud information, etc.), poor data collection, and difficult to ascertain handwriting. An online software database was used to format drilling data to IADC codedmore » daily drilling reports and generate analysis figures. Six major issues have been found in geothermal drilling operations. These problems include lost circulation, rig/equipment selection, cementing, penetration rate, drilling program, and time management. As a result of these issues, geothermal drilling averages 56.4 days longer than drilling comparable oil and gas wells in the wells in this study. Roughly $13.9 million would be lost due to non-productive time in the 21 geothermal wells and only $1.3 million in the oil and gas wells, assuming a cost of $50,000 per day. Comparable events such as drilling the same sized hole, tripping in/out, cementing, and running the same size casing took substantially less time in the oil and gas wells. Geothermal wells were drilled using older and/or less advanced technology to depths less than 10,000 feet, while oil and gas wells reached 12,500 feet faster with purpose built rigs. A new approach is now underway that will optimize drilling programs throughout the drilling industry. It is the use of Mechanical Specific Energy (MSE) as a tool to realize efficient drilling processes. However, a work-flow must also be established in order for there to be an efficient drilling program. Potential improvements for current geothermal operations are: the use of electronic records, real time services, and official glossary terms to describe rig operations, and advanced drilling rigs/technology.« less

Investigating Miocene Mediterranean-Atlantic Gateway Exchange (IMMAGE) - an amphibious drilling proposal

NASA Astrophysics Data System (ADS)

Flecker, Rachel

2017-04-01

Today Mediterranean seawater flows out through the Gibraltar Straits, forming a saline plume at intermediate depths in the Atlantic. The plume's sedimentary record of distinctive, contouritic deposits has recently been recovered during IODP Leg 339 in the Gulf of Cadiz documenting a Mediterranean contribution to Atlantic thermohaline circulation since the Pliocene. However, before the Pliocene, the conduit for Mediterranean-Atlantic exchange is unclear. Gibraltar may have already been open, but two additional marine corridors also existed through northern Morocco and southern Spain. The restriction and closure of these Miocene connections resulted in extreme salinity fluctuations in the Mediterranean, leading to the precipitation of thick evaporites. This event is known as the Messinian Salinity Crisis (MSC) and recovering a complete record of the MSC is the target of current IODP drilling proposals (e.g. DREAM). Understanding both the causes of high-amplitude salinity change in the Mediterranean and its global consequences for thermohaline circulation in the Atlantic is dependent on recovering a complete record of Mediterranean-Atlantic exchange before, during and after the MSC. This key objective of the IMMAGE drilling proposal requires core recovery on-shore at the mouths of the Betic and Rifian corridors which are now exposed on land, as well as offshore, in the Alborán Sea and on the Atlantic continental margin. Consequently to meet this objective, an amphibious drilling strategy is necessary, involving both IODP and ICDP targets. In addition to allowing us to reconstruct Mediterranean-Atlantic exchange during high amplitude salinity fluctuations and identify the conduit through which exchange occurred, the sediments recovered from IMMAGE drilling will also provide us with a unique and explicit test for ocean physics hypotheses describing the location, size and velocity of overflow plumes under conditions where the density contrast between the two water bodies is up to two orders of magnitude higher than today.

Extracting a Detailed Magnetostratigraphy From Weakly Magnetized, Oligocene to Early Miocene Sediment Drifts Recovered at IODP Site U1406 (Newfoundland Margin, Northwest Atlantic Ocean)

NASA Astrophysics Data System (ADS)

van Peer, Tim E.; Xuan, Chuang; Lippert, Peter C.; Liebrand, Diederik; Agnini, Claudia; Wilson, Paul A.

2017-11-01

Fine-grained magnetic particles in deep-sea sediments often statistically align with the ambient magnetic field during (and shortly after) deposition and can therefore record geomagnetic reversals. Correlation of these reversals to a geomagnetic polarity time scale is an important geochronological tool that facilitates precise stratigraphic correlation and dating of geological records globally. Sediments often carry a remanence strong enough for confident identification of polarity reversals, but in some cases a low signal-to-noise ratio prevents the construction of a reliable and robust magnetostratigraphy. Here we implement a data-filtering protocol, which can be integrated with the UPmag software package, to automatically reduce the maximum angular deviation and statistically mask noisy data and outliers deemed unsuitable for magnetostratigraphic interpretation. This protocol thus extracts a clearer signal from weakly magnetized sediments recovered at Integrated Ocean Drilling Program (IODP) Expedition 342 Site U1406 (Newfoundland margin, northwest Atlantic Ocean). The resulting magnetostratigraphy, in combination with shipboard and shore-based biostratigraphy, provides an age model for the study interval from IODP Site U1406 between Chrons C6Ar and C9n (˜21-27 Ma). We identify rarely observed geomagnetic directional changes within Chrons C6Br, C7r, and C7Ar, and perhaps within Subchron C8n.1n. Our magnetostratigraphy dates three intervals of unusual stratigraphic behavior within the sediment drifts at IODP Site U1406 on the Newfoundland margin. These lithostratigraphic changes are broadly concurrent with the coldest climatic phases of the middle Oligocene to early Miocene and we hypothesize that they reflect changes in bottom water circulation.

Exploring Arctic history through scientific drilling

NASA Astrophysics Data System (ADS)

ODP Leg 151 Shipboard Scientific Party

During the brief Arctic summer of 1993, the Ocean Drilling Program's research vessel JOIDES Resolution recovered the first scientific drill cores from the eastern Arctic Ocean. Dodging rafts of pack ice shed from the Arctic ice cap, the science party sampled sediments north of 80°N latitude from the Yermak Plateau, as well as from sites in Fram Strait, the northeastern Greenland margin, and the Iceland Plateau (Figure 1).The sediments collected reveal the earliest history of the connection between the North Atlantic and Arctic Oceans through the Nordic Seas. The region between Greenland and Norway first formed a series of isolated basins, sometimes with restricted deep circulation, that eventually joined and allowed deep and surface Arctic Ocean water to invade the region. A record was also retrieved that shows major glaciation in the region began about 2.5 m.y.a.

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, Terry R.

1983-01-01

A method and a cutter for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head (72) has a hollow body (76) with a generally circular base and sloping upper surface. A hollow shaft (74) extends from the hollow body (76). Cutter teeth (78) are mounted on the upper surface of the body (76) and relatively small holes (77) are formed in the body (76) between the cutter teeth (78). Relatively large peripheral flutes (80) around the body (76) allow material to drop below the drill head (72). A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale.

Analysis of stresses at the bore of a drilled ball operating in a high-speed bearing. [with stiffening web

NASA Technical Reports Server (NTRS)

Coe, H. H.; Lynch, J. E.

1973-01-01

Three-dimensional stress distributions were calculated for both a regular drilled ball with a stiffening web. The balls were 20.6 mm (0.8125 in.) in diameter and had a 12.6 mm (0.496 in.) diameter concentric hole. The stiffening web was 1.5 mm (0.06 in.) thick. The calculations showed that a large reversing tangential stress at the hole bore was reduced by one-half by the addition of the web.

Hydrogeologic data from a 2,000-foot deep core hole at Polk City, Green Swamp area, central Florida

USGS Publications Warehouse

Navoy, A.S.

1986-01-01

Two core holes were drilled to depths of 906 and 1,996 feet, respectively, within the Tertiary limestone (Floridan) aquifers, at Polk City, central Florida. Data from the two holes revealed that the bottom of the zone of vigorous groundwater circulation is confined by carbonate rocks at a depth of about 1,000 feet (863 feet below sea level). The zone of circulation is divided into two high-permeability zones. The dissolved solids of the water within the high-permeability zones is approximately 150 milligrams per liter. Within the carbonate rocks, the dissolved solids content of the water reaches about 2,000 milligrams per liter at the bottom of the core hole. Water levels in the core holes declined a total of about 16 feet as the hole was drilled; most of the head loss occurred at depths below 1,800 feet. The porosities of selected cores ranged from 1.6 to 45.3 percent; the hydraulic conductivities ranged from less than 0.000024 to 19.0786 feet per day in the horizontal direction and from less than 0.000024 to 2.99 feet per day in the vertical direction; and the ratio of vertical to horizontal permeability ranged from 0.03 to 1.98. Due to drilling problems, packer tests and geophysical logging could not be accomplished. (USGS)

Contribution of the exploration of deep crystalline fractured reservoir of Soultz to the knowledge of enhanced geothermal systems (EGS)

NASA Astrophysics Data System (ADS)

Genter, Albert; Evans, Keith; Cuenot, Nicolas; Fritsch, Daniel; Sanjuan, Bernard

2010-07-01

Over the past 20 years, the Soultz experimental geothermal site in Alsace, France, has been explored in detail by the drilling of five boreholes, three of which extend to 5 km depth. Data on geology, fluid geochemistry, temperature, microseismicity, hydraulics and geomechanics have been collected and interpreted by the various teams from the participating European countries and their international collaborators. Two reservoirs have been developed within granite at depths of 3.5 and 5 km. The reservoir at 3.5 km was formed from two wells, 450 m apart, both of which were subjected to hydraulic stimulation injections. The system was circulated continuously for 4 months at 25 kg/s in 1997 using a downhole pump, and yielded results that were extremely encouraging. The impedance reduced to 0.1 MPa/l/s, the first time this long-standing target had been attained. Construction of a deeper system began shortly afterwards with the drilling of 3 deviated wells to 5 km true vertical depth, where the temperature was 200 °C. The wells were drilled in a line, 600 m apart at reservoir depth, and all were hydraulically stimulated and subjected to acidization injections. The 3-well system was circulated under buoyancy drive for 5 months in 2005 with injection in the central well, GPK-3, and production from the two outer wells, GPK-2 and GPK-4. This showed good linkage between one doublet pair, but not the other. Further acidization operations on the low-productivity well led to its productivity increasing to almost the same level as the other wells. Construction of a power plant at the site was completed in 2008 and a trial circulation with a production pump in one well and the other shut-in was conducted with power production. Downhole pumps are now installed in both production wells in preparation for long-term circulation of the system. In this article we present an overview of the principal accomplishments at Soultz over the past two decades, and highlight the main results, issues identified, and lessons learnt.

40 CFR 146.32 - Construction requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... would result. The casing and cement used in the construction of each newly drilled well shall be... and confining zones; and (7) Type and grade of cement. (b) Appropriate logs and other tests shall be... pilot holes and reaming are used, unless the hole will be cased and cemented by circulating cement to...

Seismic While Drilling Case Study in Shengli Oilfield, Eastern China

NASA Astrophysics Data System (ADS)

Wang, L.; Liu, H.; Tong, S.; Zou, Z.

2015-12-01

Seismic while drilling (SWD) is a promising borehole seismic technique with reduction of drilling risk, cost savings and increased efficiency. To evaluate the technical and economic benefits of this new technique, we carried out SWD survey at well G130 in Shengli Oilfield of Eastern China. Well G130 is an evaluation well, located in Dongying depression at depth more than 3500m. We used an array of portable seismometers to record the surface SWD-data, during the whole drilling progress. The pilot signal was being recorded continuously, by an accelerometer mounted on the top of the drill string. There were also two seismometers buried in the drill yard, one near diesel engine and another near derrick. All the data was being recorded continuously. According to mud logging data, we have processed and analyzed all the data. It demonstrates the drill yard noise is the primary noise among the whole surface wavefield and its dominant frequency is about 20Hz. Crosscorrelation of surface signal with the pilot signal shows its SNR is severely low and there is no any obvious event of drill-bit signals. Fortunately, the autocorrelation of the pilot signal shows clear BHA multiple and drill string multiple. The period of drill string multiple can be used for establishing the reference time (so-called zero time). We identified and removed different noises from the surface SWD-data, taking advantages of wavefield analysis. The drill-bit signal was retrieved from surface SWD-data, using seismic interferometry. And a reverse vertical seismic profile (RVSP) data set for the continuous drilling depth was established. The subsurface images derived from these data compare well with the corresponding images of 3D surface seismic survey cross the well.

Borehole Stability in High-Temperature Formations

NASA Astrophysics Data System (ADS)

Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

2014-11-01

In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

Cessations and reversals of the large-scale circulation in turbulent thermal convection.

PubMed

Xi, Heng-Dong; Xia, Ke-Qing

2007-06-01

We present an experimental study of cessations and reversals of the large-scale circulation (LSC) in turbulent thermal convection in a cylindrical cell of aspect ratio (Gamma) 1/2 . It is found that cessations and reversals of the LSC occur in Gamma = 1/2 geometry an order-of-magnitude more frequently than they do in Gamma=1 cells, and that after a cessation the LSC is most likely to restart in the opposite direction, i.e., reversals of the LSC are the most probable cessation events. This contrasts sharply to the finding in Gamma=1 geometry and implies that cessations in the two geometries are governed by different dynamics. It is found that the occurrence of reversals is a Poisson process and that a stronger rebound of the flow strength after a reversal or cessation leads to a longer period of stability of the LSC. Several properties of reversals and cessations in this system are found to be statistically similar to those of geomagnetic reversals. A direct measurement of the velocity field reveals that a cessation corresponds to a momentary decoherence of the LSC.

Field testing advanced geothermal turbodrill (AGT). Phase 1 final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maurer, W.C.; Cohen, J.H.

1999-06-01

Maurer Engineering developed special high-temperature geothermal turbodrills for LANL in the 1970s to overcome motor temperature limitations. These turbodrills were used to drill the directional portions of LANL`s Hot Dry Rock Geothermal Wells at Fenton Hill, New Mexico. The Hot Dry Rock concept is to drill parallel inclined wells (35-degree inclination), hydraulically fracture between these wells, and then circulate cold water down one well and through the fractures and produce hot water out of the second well. At the time LANL drilled the Fenton Hill wells, the LANL turbodrill was the only motor in the world that would drill atmore » the high temperatures encountered in these wells. It was difficult to operate the turbodrills continuously at low speed due to the low torque output of the LANL turbodrills. The turbodrills would stall frequently and could only be restarted by lifting the bit off bottom. This allowed the bit to rotate at very high speeds, and as a result, there was excessive wear in the bearings and on the gauge of insert roller bits due to these high rotary speeds. In 1998, Maurer Engineering developed an Advanced Geothermal Turbodrill (AGT) for the National Advanced Drilling and Excavation Technology (NADET) at MIT by adding a planetary speed reducer to the LANL turbodrill to increase its torque and reduce its rotary speed. Drilling tests were conducted with the AGT using 12 1/2-inch insert roller bits in Texas Pink Granite. The drilling tests were very successful, with the AGT drilling 94 ft/hr in Texas Pink Granite compared to 45 ft/hr with the LANL turbodrill and 42 ft/hr with a rotary drill. Field tests are currently being planned in Mexico and in geothermal wells in California to demonstrate the ability of the AGT to increase drilling rates and reduce drilling costs.« less

Pressure-Letdown Machine for a Coal Reactor

NASA Technical Reports Server (NTRS)

Perkins, G. S.; Mabe, W. B.

1986-01-01

Pumps operating in reverse generate power. Conceptual pressure-letdown machine for coal-liquefaction system extracts energy from expansion of product fluid. Mud pumps, originally intended for use in oil drilling, operated in reverse so their motors act as generators. Several pumps operated in alternating phase to obtain multiple stages of letdown from inlet pressure to outlet pressure. About 75 percent of work generates inlet pressure recoverable as electrical energy.

Passive, off-axis convection through the southern flank of the Costa Rica rift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, A.T.; Becker, K.; Narasimhan, T.N.

1990-06-10

Pore fluids are passively convecting through young oceanic sediments and crust around Deep Sea Drilling Project (DSDP) site 504 on the southern flank of the Costa Rica Rift, as inferred from a variety of geological, geochemical, and geothermal observations. The presence of a fluid circulation system is supported by new data collected on Ocean Drilling Program (ODP) leg 111 and a predrilling survey cruise over the heavily sedimented, 5.9 Ma site; during the latter, elongated heat flow anomalies were mapped subparallel to structural strike, with individual measurements of twice the regional mean value, and strong lateral and vertical geochemical gradientsmore » were detected in pore waters squeezed from sediment cores. Also, there is a strong correlation between heat flow, bathymetry, sediment thickness, and inferred fluid velocities up through the sediments. Although the forces which drive passive circulation are not well understood, it has generally been thought that the length scale of heat flow variations provides a good indication of the depth of hydrothermal circulation within the oceanic crust. The widely varied geothermal and hydrogeological observations near site 504 are readily explained by a model which combines (1) basement relief, (2) irregular sediment drape, (3) largely conductive heat transfer through the sediments overlying the crust, and (4) thermal and geochemical homogenization of pore fluids at the sediment/basement interface, which results from (5) topographically induced, passive hydrothermal circulation with large aspect ratio, convection cells. This convection involves mainly the permeable, upper 200-300 m of crust; the deeper crust is not involved.« less

The deep structure of a sea-floor hydrothermal deposit

USGS Publications Warehouse

Zierenberg, R.A.; Fouquet, Y.; Miller, D.J.; Bahr, J.M.; Baker, P.A.; Bjerkgard, T.; Brunner, C.A.; Duckworth, R.C.; Gable, R.; Gieskes, J.; Goodfellow, W.D.; Groschel-Becker, H. M.; Guerin, G.; Ishibashi, J.; Iturrino, G.; James, R.H.; Lackschewitz, K.S.; Marquez, L.L.; Nehlig, P.; Peter, J.M.; Rigsby, C.A.; Schultheiss, P.; Shanks, Wayne C.; Simoneit, B.R.T.; Summit, M.; Teagle, D.A.H.; Urbat, M.; Zuffa, G.G.

1998-01-01

Hydrothermal circulation at the crests of mid-ocean ridges plays an important role in transferring heat from the interior of the Earth. A consequence of this hydrothermal circulation is the formation of metallic ore bodies known as volcanic-associated massive sulphide deposits. Such deposits, preserved on land, were important sources of copper for ancient civilizations and continue to provide a significant source of base metals (for example, copper and zinc). Here we present results from Ocean Drilling Program Leg 169, which drilled through a massive sulphide deposit on the northern Juan de Fuca spreading centre and penetrated the hydrothermal feeder zone through which the metal-rich fluids reached the sea floor. We found that the style of feeder-zone mineralization changes with depth in response to changes in the pore pressure of the hydrothermal fluids and discovered a stratified zone of high-grade copper-rich replacement mineralization below the massive sulphide deposit. This copper-rich zone represents a type of mineralization not previously observed below sea-floor deposits, and may provide new targets for land-based mineral exploration.

Tropical climate changes at millennial and orbital timescales on the Bolivian Altiplano.

PubMed

Baker, P A; Rigsby, C A; Seltzer, G O; Fritz, S C; Lowenstein, T K; Bacher, N P; Veliz, C

2001-02-08

Tropical South America is one of the three main centres of the global, zonal overturning circulation of the equatorial atmosphere (generally termed the 'Walker' circulation). Although this area plays a key role in global climate cycles, little is known about South American climate history. Here we describe sediment cores and down-hole logging results of deep drilling in the Salar de Uyuni, on the Bolivian Altiplano, located in the tropical Andes. We demonstrate that during the past 50,000 years the Altiplano underwent important changes in effective moisture at both orbital (20,000-year) and millennial timescales. Long-duration wet periods, such as the Last Glacial Maximum--marked in the drill core by continuous deposition of lacustrine sediments--appear to have occurred in phase with summer insolation maxima produced by the Earth's precessional cycle. Short-duration, millennial events correlate well with North Atlantic cold events, including Heinrich events 1 and 2, as well as the Younger Dryas episode. At both millennial and orbital timescales, cold sea surface temperatures in the high-latitude North Atlantic were coeval with wet conditions in tropical South America, suggesting a common forcing.

An Early Pleistocene high-resolution paleoclimate reconstruction from the West Turkana (Kenya) HSPDP drill site

NASA Astrophysics Data System (ADS)

Stockhecke, Mona; Beck, Catherine; Brown, Erik T.; Cohen, Andrew; Deocampo, Daniel M.; Feibel, Craig S.; Pelletier, Jon D.; Rabideaux, Nathane M.; Sier, Mark

2016-04-01

The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project (ODP), recovered ~2 km of drill core since 2012. At the HSPDP West Turkana Kaitio (WTK) site a 216 m-long core that covers the Early Pleistocene time window (1.3 to 1.87 Ma) during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. WTK carries particular interest for paleoclimate and paleoenvironmental reconstructions as it is located only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Nariokotome Boy). XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the record contains complex lithologies reflecting repeated episodes of inundation and desiccation along a dynamic lake margin. Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive paleoclimate timeseries. The power spectrum of the presented hydroclimate record peaks at Milankovitch cycles, qualifying HSPDP drill cores from the Turkana Basin to be used as high-resolution Early Pleistocene paleoclimate archive. Comparing these data with marine climate reconstructions sheds light into athmospheric processes and continental climate dynamics.

IODP workshop: developing scientific drilling proposals for the Argentina Passive Volcanic Continental Margin (APVCM) - basin evolution, deep biosphere, hydrates, sediment dynamics and ocean evolution

NASA Astrophysics Data System (ADS)

Flood, Roger D.; Violante, Roberto A.; Gorgas, Thomas; Schwarz, Ernesto; Grützner, Jens; Uenzelmann-Neben, Gabriele; Hernández-Molina, F. Javier; Biddle, Jennifer; St-Onge, Guillaume; Workshop Participants, Apvcm

2017-05-01

The Argentine margin contains important sedimentological, paleontological and chemical records of regional and local tectonic evolution, sea level, climate evolution and ocean circulation since the opening of the South Atlantic in the Late Jurassic-Early Cretaceous as well as the present-day results of post-depositional chemical and biological alteration. Despite its important location, which underlies the exchange of southern- and northern-sourced water masses, the Argentine margin has not been investigated in detail using scientific drilling techniques, perhaps because the margin has the reputation of being erosional. However, a number of papers published since 2009 have reported new high-resolution and/or multichannel seismic surveys, often combined with multi-beam bathymetric data, which show the common occurrence of layered sediments and prominent sediment drifts on the Argentine and adjacent Uruguayan margins. There has also been significant progress in studying the climatic records in surficial and near-surface sediments recovered in sediment cores from the Argentine margin. Encouraged by these recent results, our 3.5-day IODP (International Ocean Discovery Program) workshop in Buenos Aires (8-11 September 2015) focused on opportunities for scientific drilling on the Atlantic margin of Argentina, which lies beneath a key portion of the global ocean conveyor belt of thermohaline circulation. Significant opportunities exist to study the tectonic evolution, paleoceanography and stratigraphy, sedimentology, and biosphere and geochemistry of this margin.

Seismic imaging and velocity structure around the JFAST drill site in the Japan Trench: low Vp, high Vp/ Vs in the transparent frontal prism

NASA Astrophysics Data System (ADS)

Nakamura, Yasuyuki; Kodaira, Shuichi; Cook, Becky J.; Jeppson, Tamara; Kasaya, Takafumi; Yamamoto, Yojiro; Hashimoto, Yoshitaka; Yamaguchi, Mika; Obana, Koichiro; Fujie, Gou

2014-12-01

Seismic image and velocity models were obtained from a newly conducted seismic survey around the Integrated Ocean Drilling Program (IODP) Japan Trench Fast Drilling Project (JFAST) drill site in the Japan Trench. Pre-stack depth migration (PSDM) analysis was applied to the multichannel seismic reflection data to produce an accurate depth seismic profile together with a P wave velocity model along a line that crosses the JFAST site location. The seismic profile images the subduction zone at a regional scale. The frontal prism where the drill site is located corresponds to a typically seismically transparent (or chaotic) zone with several landward-dipping semi-continuous reflections. The boundary between the Cretaceous backstop and the frontal prism is marked by a prominent landward-dipping reflection. The P wave velocity model derived from the PSDM analysis shows low velocity in the frontal prism and velocity reversal across the backstop interface. The PSDM velocity model around the drill site is similar to the P wave velocity model calculated from the ocean bottom seismograph (OBS) data and agrees with the P wave velocities measured from the core experiments. The average Vp/ Vs in the hanging wall sediments around the drill site, as derived from OBS data, is significantly larger than that obtained from core sample measurements.

Magnetostratigraphy of the Miocene sediments at Háj u Duchcova and Sokolov (West Bohemia)

NASA Astrophysics Data System (ADS)

Schnabl, Petr; Man, Otakar; Matys Grygar, Tomáš; Mach, Karel; Kdýr, Šimon; Čížková, Kristýna; Pruner, Petr; Martínek, Karel; Rojík, Petr

2017-04-01

Magnetostratigraphic investigation was conducted on the newly excavated drill core HD-50 and previously retreived drill cores DP-333-09 and JP-585-10. The new drill core HD-50 was sampled at the old coal mine 1.Máj near Háj u Duchcova in the Most Basin, while the DP-333-09 and JP-585-10 are from the benches of opencast coal mines Družba and Jiří in the Sokolov Basin. Both basins are parts of one segment of the European Cenozoic Rift System. The sediments in both basins are of Burdigalian age (lower Miocene). Their lithology mainly comprise fossil-free clays/silts above the main coal seam, with two phosphatic horizons with mineral crandalite in the Most Basin and several greigite layers in the Sokolov Basin. Anisotropy of magnetic susceptibility (AMS), alternate field demagnetization and remanent magnetization were measured in all samples. Unusually behaving samples with extremely high magnetic susceptibility (siderite), prolate anisotropy of AMS and samples with the angle of the main AMS axis exceeding 20 degrees was excluded from further evaluation. The sedimentation rate was computed by multivariate spectral analysis on data acquired by X-ray fluorescence. The spectral analysis was performed with our original software solution for identification of typical frequencies and their assignement to Milanković cycles.[1] The sedimentation rate (after compaction) was around 15 cm/ky for the drill core DP-333-09 and around 30 cm/ky for the core JP-585-10. The sediment succession above the coal seam at drill core DP-333-09 starts with 20 meters, in which the magnetic polarity could not be reconstructed (70 - 50 m), then there is a top part of reverse zone (50 - 49 m) and short normal subzone above it (49 - 48 m). Above that there is the second reverse zone (45 - 4 m). Two additional magnetozones above that could be found only in the drill core HD-50 from the Most Basin. The drill core JP-585-10 begins with 14 meters of disturbed zone (94 - 80 m), then 12 meters of normal polarity (69 - 80 m) was found. Above that, after a small gap of magnetically disturbed sediments, there are 60 meters of sediments with reverse polarity (62 - 2 m) with short normal excursion at the upper half (24 - 17 m). According to the detailed analysis of drill core HK591 (Matys Grygar et al. 2014), we suppose, that the succession begins in C5En (only JP-585-10), then C5Dr. Validity of subzone C5Dr.1n in the drills JP-585-10 and DP-333-09 is still under discussion. The zone C5Cr could be found only in the HD-50 core. In comparison of the interpreted polarities with ATNTS2012 the time span in the studied cores is approximately 17.5 to 17.9 Ma for DP-333-09, 17.8 to 18.1 for JP-585-[2]10 and 17.1 to 17.7 Ma for HD-50. Additional investigation should be done. The research was supported by Czech Science Foundation GAČR, project n. 16-00800S. Matys Grygar, T., Mach, K., Pruner, P., Schnabl, P., Laurin, J., Martinez, M., 2014. A lacustrine record of the early stage of the Miocene Climatic Optimum in Central Europe from the Most Basin, Ohře (Eger) Graben, Czech Republic, Geol. Mag. 151 (6), 1013-1033.

Hydraulic Shearing and Hydraulic Jacking Observed during Hydraulic Stimulations in Fractured Geothermal Reservoir in Pohang, Korea

NASA Astrophysics Data System (ADS)

Min, K. B.; Park, S.; Xie, L.; Kim, K. I.; Yoo, H.; Kim, K. Y.; Choi, J.; Yoon, K. S.; Yoon, W. S.; Lee, T. J.; Song, Y.

2017-12-01

Enhanced Geothermal System (EGS) relies on sufficient and irreversible enhancement of reservoir permeability through hydraulic stimulation and possibility of such desirable change of permeability is an open question that can undermine the universality of EGS concept. We report results of first hydraulic stimulation campaign conducted in two deep boreholes in fractured granodiorite geothermal reservoir in Pohang, Korea. Borehole PX-1, located at 4.22 km, was subjected to the injection of 3,907 m3 with flow rate of up to 18 kg/s followed by bleeding off of 1,207 m3. The borehole PX-2, located at 4.35 km, was subjected to the injection of 1,970 m3 with flow rate of up to 46 kg/sIn PX-1, a sharp distinct decline of wellhead pressure was observed at around 16 MPa of wellhead pressure which was similar to the predicted injection pressure to induce hydraulic shearing. Injectivity interpretation before and after the hydraulic shearing indicates that permanent increase of permeability was achieved by a factor of a few. In PX-2, however, injectivity was very small and hydraulic shearing was not observed due possibly to the near wellbore damage made by the remedying process of lost circulation such as using lost circulation material during drilling. Flow rate of larger than 40 kg/s was achieved at very high well head pressure of nearly 90 MPa. Hydraulic jacking, that is reversible opening and closure of fracture with change of injection pressure, was clearly observed. Although sharp increase of permeability due to fracture opening was achieved with elevated injection pressure, the increased permeability was reversed with decreased injection pressure.Two contrasting response observed in the same reservoir at two different boreholes which is apart only 600 m apart provide important implication that can be used for the stimulation strategy for EGS.This work was supported by the New and Renewable Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) through a grant funded by the Korean Government's Ministry of Trade, Industry & Energy (No. 20123010110010).

GHGfrack: An Open-Source Model for Estimating Greenhouse Gas Emissions from Combustion of Fuel during Drilling and Hydraulic Fracturing.

PubMed

Vafi, Kourosh; Brandt, Adam

2016-07-19

This paper introduces GHGfrack, an open-source engineering-based model that estimates energy consumption and associated GHG emissions from drilling and hydraulic fracturing operations. We describe verification and calibration of GHGfrack against field data for energy and fuel consumption. We run GHGfrack using data from 6927 wells in Eagle Ford and 4431 wells in Bakken oil fields. The average estimated energy consumption in Eagle Ford wells using lateral hole diameters of 8 (3)/4 and 6 (1)/8 in. are 2.25 and 2.73 TJ/well, respectively. The average estimated energy consumption in Bakken wells using hole diameters of 6 in. for horizontal section is 2.16 TJ/well. We estimate average greenhouse gas (GHG) emissions of 419 and 510 tonne of equivalent CO2 per well (tonne of CO2 eq/well) for the two aforementioned assumed geometries in Eagle Ford, respectively, and 417 tonne of CO2 eq/well for the case of Bakken. These estimates are limited only to GHG emissions from combustion of diesel fuel to supply energy only for rotation of drill string, drilling mud circulation, and fracturing pumps. Sensitivity analysis of the model shows that the top three key variables in driving energy intensity in drilling are the lateral hole diameter, drill pipe internal diameter, and mud flow rate. In hydraulic fracturing, the top three are lateral casing diameter, fracturing fluid volume, and length of the lateral.

46 CFR 108.171 - Class I, Division 1 locations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... locations. The following are Class I, Division 1 locations: (a) An enclosed space that contains any part of the mud circulating system that has an opening into the space and is between the well and final... possible source of gas release. (c) An enclosed space that is on the drill floor, and is not separated by a...

46 CFR 108.171 - Class I, Division 1 locations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... locations. The following are Class I, Division 1 locations: (a) An enclosed space that contains any part of the mud circulating system that has an opening into the space and is between the well and final... possible source of gas release. (c) An enclosed space that is on the drill floor, and is not separated by a...

46 CFR 108.171 - Class I, Division 1 locations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... locations. The following are Class I, Division 1 locations: (a) An enclosed space that contains any part of the mud circulating system that has an opening into the space and is between the well and final... possible source of gas release. (c) An enclosed space that is on the drill floor, and is not separated by a...

46 CFR 108.171 - Class I, Division 1 locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... locations. The following are Class I, Division 1 locations: (a) An enclosed space that contains any part of the mud circulating system that has an opening into the space and is between the well and final... possible source of gas release. (c) An enclosed space that is on the drill floor, and is not separated by a...

46 CFR 108.171 - Class I, Division 1 locations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... locations. The following are Class I, Division 1 locations: (a) An enclosed space that contains any part of the mud circulating system that has an opening into the space and is between the well and final... possible source of gas release. (c) An enclosed space that is on the drill floor, and is not separated by a...

Downhole vacuum cleans up tough fishing, milling jobs

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaLande, P.; Flanders, B.

1996-02-01

A unique tool developed to effect reverse circulation downhole is being used successfully in problem milling and fishing operations where conventional techniques fail to recover junk in the hole. Jointly developed by several major operators in conjunction with Baker Oil Tools, the patented Reverse Circulating Tool (RCT) acts as a downhole vacuum cleaner, catching and retaining debris circulated from the wellbore while allowing fishing, milling and washover operations to continue uninterrupted. As described in several case histories overviewed, the unique vacuuming action efficiently cleans up junk and debris in even the most difficult fishing and milling applications. Downhole operations proceedmore » normally, but without threat of damage from milled debris. Developers hold both mechanical and method patents on the RCT.« less

Experimental study of improved rheology and lubricity of drilling fluids enhanced with nano-particles

NASA Astrophysics Data System (ADS)

Bég, O. Anwar; Espinoza, D. E. Sanchez; Kadir, Ali; Shamshuddin, MD.; Sohail, Ayesha

2018-04-01

An experimental study of the rheology and lubricity properties of a drilling fluid is reported, motivated by applications in highly deviated and extended reach wells. Recent developments in nanofluids have identified that the judicious injection of nano-particles into working drilling fluids may resolve a number of issues including borehole instability, lost circulation, torque and drag, pipe sticking problems, bit balling and reduction in drilling speed. The aim of this article is, therefore, to evaluate the rheological characteristics and lubricity of different nano-particles in water-based mud, with the potential to reduce costs via a decrease in drag and torque during the construction of highly deviated and ERD wells. Extensive results are presented for percentage in torque variation and coefficient of friction before and after aging. Rheology is evaluated via apparent viscosity, plastic viscosity and gel strength variation before and after aging for water-based muds (WBM). Results are included for silica and titanium nano-particles at different concentrations. These properties were measured before and after aging the mud samples at 80 °C during 16 h at static conditions. The best performance was shown with titanium nano-particles at a concentration of 0.60% (w/w) before aging.

Influence of drilling operations on drilling mud gas monitoring during IODP Exp. 338 and 348

NASA Astrophysics Data System (ADS)

Hammerschmidt, Sebastian; Toczko, Sean; Kubo, Yusuke; Wiersberg, Thomas; Fuchida, Shigeshi; Kopf, Achim; Hirose, Takehiro; Saffer, Demian; Tobin, Harold; Expedition 348 Scientists, the

2014-05-01

The history of scientific ocean drilling has developed some new techniques and technologies for drilling science, dynamic positioning being one of the most famous. However, while industry has developed newer tools and techniques, only some of these have been used in scientific ocean drilling. The introduction of riser-drilling, which recirculates the drilling mud and returns to the platform solids and gases from the formation, to the International Ocean Drilling Program (IODP) through the launch of the Japan Agency of Marine Earth-Science and Technology (JAMSTEC) riser-drilling vessel D/V Chikyu, has made some of these techniques available to science. IODP Expedition 319 (NanTroSEIZE Stage 2: riser/riserless observatory) was the first such attempt, and among the tools and techniques used was drilling mud gas analysis. While industry regularly conducts drilling mud gas logging for safety concerns and reservoir evaluation, science is more interested in other components (e.g He, 222Rn) that are beyond the scope of typical mud logging services. Drilling mud gas logging simply examines the gases released into the drilling mud as part of the drilling process; the bit breaks and grinds the formation, releasing any trapped gases. These then circulate within the "closed circuit" mud-flow back to the drilling rig, where a degasser extracts these gases and passes them on to a dedicated mud gas logging unit. The unit contains gas chromatographs, mass spectrometers, spectral analyzers, radon gas analyzers, and a methane carbon isotope analyzer. Data are collected and stored in a database, together with several drilling parameters (rate of penetration, mud density, etc.). This initial attempt was further refined during IODP Expeditions 337 (Deep Coalbed Biosphere off Shimokita), 338 (NanTroSEIZE Stage 3: NanTroSEIZE Plate Boundary Deep Riser 2) and finally 348 (NanTroSEIZE Stage 3: NanTroSEIZE Plate Boundary Deep Riser 3). Although still in its development stage for scientific application, this technique can provide a valuable suite of measurements to complement more traditional IODP shipboard measurements. Here we present unpublished data from IODP Expeditions 338 and 348, penetrating the Nankai Accretionary wedge to 3058.5 meters below seafloor. Increasing mud density decreased degasser efficiency, especially for higher hydrocarbons. Blurring of the relative variations in total gas by depth was observed, and confirmed with comparison to headspace gas concentrations from the cored interval. Theoretically, overpressured zones in the formation can be identified through C2/C3 ratios, but these ratios are highly affected by changing drilling parameters. Proper mud gas evaluations will need to carefully consider the effects of variable drilling parameters when designing experiments and interpreting the data.

Geothermal Program Review XI: proceedings. Geothermal Energy - The Environmental Responsible Energy Technology for the Nineties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-10-01

These proceedings contain papers pertaining to current research and development of geothermal energy in the USA. The seven sections of the document are: Overview, The Geysers, Exploration and Reservoir Characterization, Drilling, Energy Conversion, Advanced Systems, and Potpourri. The Overview presents current DOE energy policy and industry perspectives. Reservoir studies, injection, and seismic monitoring are reported for the geysers geothermal field. Aspects of geology, geochemistry and models of geothermal exploration are described. The Drilling section contains information on lost circulation, memory logging tools, and slim-hole drilling. Topics considered in energy conversion are efforts at NREL, condensation on turbines and geothermal materials.more » Advanced Systems include hot dry rock studies and Fenton Hill flow testing. The Potpourri section concludes the proceedings with reports on low-temperature resources, market analysis, brines, waste treatment biotechnology, and Bonneville Power Administration activities. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.« less

Libya: a dynamic Arab oil power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, M.

1965-06-01

Libya has become the most dynamic oil-producing nation in the world. Less than 4 yr ago, Libya exported only peanuts, olive oil, and hides. Today, in crude-oil production Libya ranks eighth in the world, with daily production of 1.2 million bbl. Twenty-five oil companies hold concessions and have spent $1.3 billion developing reserves. Petroleum has brought new wealth to the country- an estimated $272 million in 1965. Some 2.75 million ft of hole was drilled in 1964, resulting in 97 oil fields and 4 major basins. Lost circulation has been a problem Transportation and communication are difficult in the vastmore » Libyan desert. Water-contaminated crude and high salt content have plagued production. These problems are being solved. With 45 drillings rigs active, crude production is expected to reach 2 million bpd by 1966. Most of the rigs used are trailer-mounted, unitized 8,000-12,000 ft capacity, that have been specially adapted to work in the Sahara. The drilling-completion programs are briefly described.« less

Optimizing glenosphere position and fixation in reverse shoulder arthroplasty, Part One: The twelve-mm rule.

PubMed

Kelly, James D; Humphrey, C Scott; Norris, Tom R

2008-01-01

The Aequalis Reversed Shoulder Prosthesis (Tornier, Inc., Edina, MN) is a successful treatment option for older, low-demand patients with rotator cuff arthropathy. Scapular notching is the most common radiographic complication and is associated with poorer intermediate-term clinical outcomes. Aligning the lower border of the glenosphere baseplate with the inferior glenoid rim has been recommended to reduce this complication, but guidelines for achieving this positioning are currently lacking. The purpose of this study is to develop a rule of thumb that will facilitate proper glenosphere component positioning intraoperatively. Utilizing a computed tomography-templating protocol, we found that the ideal location of the drill hole for the baseplate post was 11.5 +/- 1.0 mm above the inferior glenoid rim. On the basis of measurements from 10 implanted cadaveric specimens, we concluded that drilling the baseplate posthole 12 mm above the inferior glenoid rim-the 12-mm rule-will result in excellent glenosphere position in most cases.

Pearl Harbor and America's Homefront Children: First Fears, Blackouts, Air Raid Drills, and Nightmares.

ERIC Educational Resources Information Center

Tuttle, William M., Jr.

In conducting research about U.S. homefront children during the Second World War, a professor of history wrote to the 100 largest-circulation newspapers in the United States as well as 75 African-American, Hispanic American, and Jewish-American newspapers and magazines seeking letters from people who experienced the War as children. More than…

Rapid hydrothermal cooling above the axial melt lens at fast-spreading mid-ocean ridge

NASA Astrophysics Data System (ADS)

Zhang, Chao; Koepke, Juergen; Kirchner, Clemens; Götze, Niko; Behrens, Harald

2014-09-01

Axial melt lenses sandwiched between the lower oceanic crust and the sheeted dike sequences at fast-spreading mid-ocean ridges are assumed to be the major magma source of oceanic crust accretion. According to the widely discussed ``gabbro glacier'' model, the formation of the lower oceanic crust requires efficient cooling of the axial melt lens, leading to partial crystallization and crystal-melt mush subsiding down to lower crust. These processes are believed to be controlled by periodical magma replenishment and hydrothermal circulation above the melt lens. Here we quantify the cooling rate above melt lens using chemical zoning of plagioclase from hornfelsic recrystallized sheeted dikes drilled from the East Pacific at the Integrated Ocean Drilling Program Hole 1256D. We estimate the cooling rate using a forward modelling approach based on CaAl-NaSi interdiffusion in plagioclase. The results show that cooling from the peak thermal overprint at 1000-1050°C to 600°C are yielded within about 10-30 years as a result of hydrothermal circulation above melt lens during magma starvation. The estimated rapid hydrothermal cooling explains how the effective heat extraction from melt lens is achieved at fast-spreading mid-ocean ridges.

Borehole model for simulation transport geothermal heat with heat pipe system and with forced circulation of heat carrier

NASA Astrophysics Data System (ADS)

Jakubský, Michal; Lenhard, Richard; Vantúch, Martin; Malcho, Milan

2012-04-01

In the call OPVaV-2008/2.2/01-SORO Operational Programme Research and Development - knowledge and technology transfer from research and development into practice (ITMS-26220220057), whose strategic goal is "Device to use low-potential geothermal heat without forced circulation of heat carrier deep in the well "in the Department of Energy laboratory techniques to construct a simulator of transport low potential of geothermal energy in comparative test-drilling in the laboratory. The article describes a device that was designed as a scale model of two deep boreholes each of which withdraws the earth's heat by heat transfer technology and heat carrier. Device using forced circulation of heat carrier will respond in the construction of equipment currently used to transport heat from deep borehole. As the heat carrier will be used CO2. Facilities without using forced circulation of heat carrier, the new technology, which will be used as heat carrier ammonia (NH3).

Identification and characterization of the active hydrothermal deposits in Okinawa Trough, SW Japan: Estimates from logging-while-drilling

NASA Astrophysics Data System (ADS)

Saito, S.; Sanada, Y.; Moe, K.; Kido, Y. N.; Hamada, Y.; Kumagai, H.; Nozaki, T.; Takai, K.; Suzuki, K.

2015-12-01

A scientific drilling expedition was conducted at an active hydrothermal field on the Iheya-North Knoll by D/V Chikyu in 2014 (Expedition 907) as a part of "Next-generation Technology for Ocean Resources Survey" of the Cross-ministerial Strategic Innovation Promotion Program. During the expedition logging while drilling (LWD) was deployed to constrain the area of the fluid reservoir beneath seafloor followed by three coring holes down to 150 meter below the seafloor (mbsf). The LWD system is composed of arcVISION for resistivity and natural gamma ray measurement and TeleScope for real-time transmission of drilling parameters and arcVISION data. Five sites (C9011-15) at the Iheya-North Original Site and one site (C9016) at Aki Site were drilled with LWD. At C9012 and C9016, the arcVISION detected temperature anomaly up to 84℃ at 234 mbsf and up to 39℃ at 80 mbsf, respectively. The temperature quickly increases at that depth and it would reflect the existence of high-temperature heat source along borehole. Due to the continuous fluid circulation during drilling, the measured temperature does not indicate in-situ temperature, but it reflects the heat disturbed by the cold circulated water instead. High quality resistivity and natural gamma ray data were acquired at six sites. The log curves at Site C9016 show characteristic response; the natural gamma ray log exhibits extremely high radiation (>500 gAPI) at 7-13 and 23-31 mbsf (Zone A). In the underlying interval of 31-40 mbsf, the resistivity log exhibits extremely low value (<0.2 ohm-m) (Zone B). Then the resistivity log exhibits higher value (~10 ohm-m) and the natural gamma ray log shows very low radiation (<50 gAPI) at the interval of 41-48 mbsf (Zone C). The log characteristics in Zone A, B, and C can be interpreted as a series of K-rich alteration zone, sulfide zone, and low-K hard (silicified) sediments, respectively. The LWD-based lithological interpretation was confirmed by the following core description. Zones A and B can be correlated to altered clay zone and sulfide zone including sphalerite, galena, chalcopyrite, and pyrite. Our results show that LWD is a powerful tool for the identification and characterization of submarine hydrothermal deposits and LWD survey enhances the successful recovery of sulfide samples.

Unique microbial community in drilling fluids from Chinese continental scientific drilling

USGS Publications Warehouse

Zhang, Gengxin; Dong, Hailiang; Jiang, Hongchen; Xu, Zhiqin; Eberl, Dennis D.

2006-01-01

Circulating drilling fluid is often regarded as a contamination source in investigations of subsurface microbiology. However, it also provides an opportunity to sample geological fluids at depth and to study contained microbial communities. During our study of deep subsurface microbiology of the Chinese Continental Scientific Deep drilling project, we collected 6 drilling fluid samples from a borehole from 2290 to 3350 m below the land surface. Microbial communities in these samples were characterized with cultivation-dependent and -independent techniques. Characterization of 16S rRNA genes indicated that the bacterial clone sequences related to Firmicutes became progressively dominant with increasing depth. Most sequences were related to anaerobic, thermophilic, halophilic or alkaliphilic bacteria. These habitats were consistent with the measured geochemical characteristics of the drilling fluids that have incorporated geological fluids and partly reflected the in-situ conditions. Several clone types were closely related to Thermoanaerobacter ethanolicus, Caldicellulosiruptor lactoaceticus, and Anaerobranca gottschalkii, an anaerobic metal-reducer, an extreme thermophile, and an anaerobic chemoorganotroph, respectively, with an optimal growth temperature of 50–68°C. Seven anaerobic, thermophilic Fe(III)-reducing bacterial isolates were obtained and they were capable of reducing iron oxide and clay minerals to produce siderite, vivianite, and illite. The archaeal diversity was low. Most archaeal sequences were not related to any known cultivated species, but rather to environmental clone sequences recovered from subsurface environments. We infer that the detected microbes were derived from geological fluids at depth and their growth habitats reflected the deep subsurface conditions. These findings have important implications for microbial survival and their ecological functions in the deep subsurface.

New mud gas monitoring system aboard D/V Chikyu

NASA Astrophysics Data System (ADS)

Kubo, Yusuke; Inagaki, Fumio; Eguchi, Nobuhisa; Igarashi, Chiaki

2013-04-01

Mud gas logging has been commonly used in oil industry and continental scientific drilling to detect mainly hydrocarbon gases from the reservoir formation. Quick analysis of the gas provides almost real-time information which is critical to evaluate the formation and, in particular, safety of drilling operation. Furthermore, mud gas monitoring complements the lack of core or fluid samples particularly in a deep hole, and strengthen interpretations of geophysical logs. In scientific ocean drilling, on the other hand, mud gas monitoring was unavailable in riserless drilling through the history of DSDP and ODP, until riser drilling was first carried out in 2009 by D/V Chikyu. In IODP Exp 319, GFZ installed the same system with that used in continental drilling aboard Chikyu. High methane concentrations are clearly correlated with increased wood content in the cuttings. The system installation was, however, temporary and gas separator was moved during the expedition for a technical reason. In 2011, new mud gas monitoring system was installed aboard Chikyu and was used for the first time in Exp 337. The gas separator was placed on a newly branched bypass mud flow line, and the gas sample was sent to analysis unit equipped with methane carbon isotope analyzer in addition to mass spectrometer and gas chromatograph. The data from the analytical instruments is converted to depth profiles by calculating the lag effects due to mud circulation. Exp 337 was carried out from July 26 to Sep 30, 2011, at offshore Shimokita peninsula, northeast Japan, targeting deep sub-seafloor biosphere in and around coal bed. Data from the hole C0020A, which was drilled to 2466 mbsf with riser drilling, provided insights into bio-geochemical process through the depth of the hole. In this presentation, we show the design of Chikyu's new mud gas monitoring system, with preliminary data from Exp 337.

Transesterification reaction for synthesis of palm-based ethylhexyl ester and formulation as base oil for synthetic drilling fluid.

PubMed

Abdul Habib, Nor Saiful Hafiz; Yunus, Robiah; Rashid, Umer; Taufiq-Yap, Yun H; Abidin, Zurina Zainal; Syam, Azhari Muhammad; Irawan, Sonny

2014-01-01

The use of vegetable oil-based ester as a base fluid in synthetic drilling fluid has become a trend in drilling operations due to its environmental advantages. The transesterification reaction of palm oil methyl ester (POME) with 2-ethylhexanol (2EH) produced 98% of palm oil-based ethylhexyl ester in less than 30 minutes. Since the transesterification reaction of POME with 2EH is a reversible reaction, its kinetics was studied in the presence of excess EH and under vacuum. The POME-to-EH molar ratio and vacuum pressure were held constant at 1:2 and 1.5 mbar respectively and the effects of temperature (70 to 110°C) were investigated. Using excess of EH and continual withdrawal of methanol via vacuum promoted the reaction to complete in less than 10 minutes. The rate constant of the reaction (k) obtained from the kinetics study was in the range of 0.44 to 0.66 s⁻¹ and the activation energy was 15.6 kJ.mol⁻¹. The preliminary investigations on the lubrication properties of drilling mud formulated with palm oil-based 2EH ester indicated that the base oil has a great potential to substitute the synthetic ester-based oil for drilling fluid. Its high kinematic viscosity provides better lubrication to the drilling fluid compared to other ester-based oils. The pour point (-15°C) and flash point (204°C) values are superior for the drilling fluid formulation. The plastic viscosity, HPHT filtrate loss and emulsion stability of the drilling fluid had given acceptable values, while gel strength and yield point could be improved by blending it with proper additives.

Determining the Area of Review for Industrial Waste Disposal Wells.

DTIC Science & Technology

1981-12-01

pressure increases sufficiently to force formation fluids and/or injected wastes up abandoned well bores to contaminate underground sources of drinking...Drilling Mud Circulating System . . 72 9. Increase in Gel Strength of Various Mud Types With Time . . . . . . . . . . . . . . . . . . 96 10. Gel... increased fluid pressure in a disposal zone which results from a waste injection operation may force injected and/or formation fluid to migrate up an

DOE Office of Scientific and Technical Information (OSTI.GOV)

William C. Maurer; William J. McDonald; Thomas E. Williams

Underbalanced drilling is experiencing growth at a rate that rivals that of horizontal drilling in the mid-1980s and coiled-tubing drilling in the 1990s. Problems remain, however, for applying underbalanced drilling in a wider range of geological settings and drilling environments. This report addresses developments under this DOE project to develop products aimed at overcoming these problems. During Phase I of the DOE project, market analyses showed that up to 12,000 wells per year (i.e., 30% of all wells) will be drilled underbalanced in the U.S.A. within the next ten years. A user-friendly foam fluid hydraulics model (FOAM) was developed formore » a PC Windows environment during Phase I. FOAM predicts circulating pressures and flow characteristics of foam fluids used in underbalanced drilling operations. FOAM is based on the best available mathematical models, and was validated through comparison to existing models, laboratory test data and field data. This model does not handle two-phase flow or air and mist drilling where the foam quality is above 0.97. This FOAM model was greatly expanded during Phase II including adding an improved foam rheological model and a ''matching'' feature that allows the model to be field calibrated. During Phase I, a lightweight drilling fluid was developed that uses hollow glass spheres (HGS) to reduce the density of the mud to less than that of water. HGS fluids have several advantages over aerated fluids, including they are incompressible, they reduce corrosion and vibration problems, they allow the use of mud-pulse MWD tools, and they eliminate high compressor and nitrogen costs. Phase II tests showed that HGS significantly reduce formation damage with water-based drilling and completion fluids and thereby potentially can increase oil and gas production in wells drilled with water-based fluids. Extensive rheological testing was conducted with HGS drilling and completion fluids during Phase II. These tests showed that the HGS fluids act similarly to conventional fluids and that they have potential application in many areas, including underbalanced drilling, completions, and riserless drilling. Early field tests under this project are encouraging. These led to limited tests by industry (which are also described). Further field tests and cost analyses are needed to demonstrate the viability of HGS fluids in different applications. Once their effectiveness is demonstrated, they should find widespread application and should significantly reduce drilling costs and increase oil and gas production rates. A number of important oilfield applications for HGS outside of Underbalanced Drilling were identified. One of these--Dual Gradient Drilling (DGD) for deepwater exploration and development--is very promising. Investigative work on DGD under the project is reported, along with definition of a large joint-industry project resulting from the work. Other innovative products/applications are highlighted in the report including the use of HGS as a cement additive.« less

When did Mediterranean Outflow Water begin to circulate into the North Atlantic?

NASA Astrophysics Data System (ADS)

Hernández Molina, Francisco Javier; Stow, Dorrik A. V.; Zarikian, Carlos

2014-05-01

The southwestern Iberian margin records critical evidence of Mediterranean Outflow Water (MOW) following its exit through the Strait of Gibraltar. Data collected during Integrated Ocean Drilling Program (IODP) Expedition 339 provide new constraints on MOW circulation patterns from Pliocene to present time, which indicate an alternative sequence of events in the establishment of global ocean circulation patterns. Following the opening of the Strait of Gibraltar (5.46 Ma), a limited volume of weak MOW entered the Atlantic at about 4.5- 4.2 Ma. Two depositional hiatuses evident at 3.2-3.0 Ma and 2.4-2.1 Ma indicate that significant MOW circulation into the North Atlantic did not occur until the Late Pliocene and early Pleistocene. These hiatuses accompany other changes in sedimentary processes. A younger event at 0.9-0.7 Ma suggests additional Pleistocene phase of MOW intensification. These events are coeval with global changes in deep-water sedimentation associated with shifts in global thermohaline circulation (THC). The events evident from sediment cores and seismic records interpreted here suggest that MOW provided an important, additional component of warm, saline waters to northern latitudes, thus enhancing Atlantic Meridional Overturning Circulation (AMOC). Similar changes have been globally described, suggesting a link between climatic shifts, THC and plate tectonic events.

The hydrogeology of the Costa Rica Rift as constrained by results of ocean drilling program downhole experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, A.T.; Becker, K.; Narasimhan, T.

1990-06-01

Pore fluids are passively convecting through young oceanic sediments and crust around Deep Sea Drilling Project (DSDP) site 504 on the southern flank of the Costa Rica Rift, as inferred from a variety of geological, geochemical, and geothermal observations. The presence of a fluid circulation system is supported by new data collected on Ocean Drilling Program (ODP) Leg 111 and a predrilling survey cruise over the heavily sedimented, 5.9 Ma site; during the latter, elongated heat flow anomalies were mapped subparallel to structural strike, with individual measurements of twice the regional mean value, and large lateral and vertical geochemical gradientsmore » were detected in pore waters squeezed from sediment cores. Also, there is a strong correlation between heat flow, bathymetry, sediment thickness, and inferred fluid velocities up through the sediments. On an earlier DSDP leg, an 8-bar underpressure was measured in the upper 200 m of basement beneath thick sediment cover. The widely varied geothermal and hydrogeological observations near site 504 are readily explained by a model that combines (1) basement relief, (2) irregular sediment drape, (3) largely conductive heat transfer through the sediments overlying the crust, and (4) thermal and geochemical homogenization of pore fluids at the sediment/basement interface, which results from (5) topographically induced, passive hydrothermal circulation with large aspect ratio, convection cells. This convection involves mainly the permeable, upper 200-300 m of crust; the deeper crust is not involved. This convection is induced through a combination of buoyancy fluxes, owing to heating from below, and topographic variations on the seafloor and at the basement-sediment interface.« less

Improving the trajectory of transpedicular transdiscal lumbar screw fixation with a computer-assisted 3D-printed custom drill guide

PubMed Central

Shao, Zhen-Xuan; Wang, Jian-Shun; Lin, Zhong-Ke; Ni, Wen-Fei; Wang, Xiang-Yang

2017-01-01

Transpedicular transdiscal screw fixation is an alternative technique used in lumbar spine fixation; however, it requires an accurate screw trajectory. The aim of this study is to design a novel 3D-printed custom drill guide and investigate its accuracy to guide the trajectory of transpedicular transdiscal (TPTD) lumbar screw fixation. Dicom images of thirty lumbar functional segment units (FSU, two segments) of L1–L4 were acquired from the PACS system in our hospital (patients who underwent a CT scan for other abdomen diseases and had normal spine anatomy) and imported into reverse design software for three-dimensional reconstructions. Images were used to print the 3D lumbar models and were imported into CAD software to design an optimal TPTD screw trajectory and a matched custom drill guide. After both the 3D printed FSU models and 3D-printed custom drill guide were prepared, the TPTD screws will be guided with a 3D-printed custom drill guide and introduced into the 3D printed FSU models. No significant statistical difference in screw trajectory angles was observed between the digital model and the 3D-printed model (P > 0.05). Our present study found that, with the help of CAD software, it is feasible to design a TPTD screw custom drill guide that could guide the accurate TPTD screw trajectory on 3D-printed lumbar models. PMID:28717599

The Yucca Mountain Project prototype air-coring test, U12g tunnel, Nevada test site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ray, J.M.; Newsom, J.C.

1994-12-01

The Prototype Air-Coring Test was conducted at the Nevada Test Site (NTS) G-Tunnel facility to evaluate standard coring techniques, modified slightly for air circulation, for use in testing at a prospective nuclear waste repository at Yucca Mountain, Nevada. Air-coring technology allows sampling of subsurface lithology with minimal perturbation to ambient characteristic such as that required for exploratory holes near aquifers, environmental applications, and site characterization work. Two horizontal holes were cored, one 50 ft long and the other 150 ft long, in densely welded fractured tuff to simulate the difficult drilling conditions anticipated at Yucca Mountain. Drilling data from sevenmore » holes on three other prototype tests in nonwelded tuff were also collected for comparison. The test was used to establish preliminary standards of performance for drilling and dust collection equipment and to assess procedural efficiencies. The Longyear-38 drill achieved 97% recovery for HQ-size core (-2.5 in.), and the Atlas Copco dust collector (DCT-90) captured 1500 lb of fugitive dust in a mine environment with only minor modifications. Average hole production rates were 6-8 ft per 6-h shift in welded tuff and almost 20 ft per shift on deeper holes in nonwelded tuff. Lexan liners were successfully used to encapsulate core samples during the coring process and protect core properties effectively. The Prototype Air-Coring Test demonstrated that horizontal air coring in fractured welded tuff (to at least 150 ft) can be safely accomplished by proper selection, integration, and minor modification of standard drilling equipment, using appropriate procedures and engineering controls. The test also indicated that rig logistics, equipment, and methods need improvement before attempting a large-scale dry drilling program at Yucca Mountain.« less

Quantitative evaluation of hand cranking a roller pump in a crisis management drill.

PubMed

Tomizawa, Yasuko; Tokumine, Asako; Ninomiya, Shinji; Momose, Naoki; Matayoshi, Toru

2008-01-01

The heart-lung machines for open-heart surgery have improved over the past 50 years; they rarely break down and are almost always equipped with backup batteries. The hand-cranking procedure only becomes necessary when a pump breaks down during perfusion or after the batteries have run out. In this study, the performance of hand cranking a roller pump was quantitatively assessed by an objective method using the ECCSIM-Lite educational simulator system. A roller pump connected to an extracorporeal circuit with an oxygenator and with gravity venous drainage was used. A flow sensor unit consisting of electromagnetic sensors was used to measure arterial and venous flow rates, and a built-in pressure sensor was used to measure the water level in the reservoir. A preliminary study of continuous cranking by a team of six people was conducted as a surprise drill. This system was then used at a perfusion seminar. At the seminar, 1-min hand-cranking drills were conducted by volunteers according to a prepared scenario. The data were calculated on site and trend graphs of individual performances were given to the participants as a handout. Preliminary studies showed that each person's performance was different. Results from 1-min drills showed that good performance was not related to the number of clinical cases experienced, years of practice, or experience in hand cranking. Hand cranking to maintain the target flow rate could be achieved without practice; however, manipulating the venous return clamp requires practice. While the necessity of performing hand cranking during perfusion due to pump failure is rare, we believe that it is beneficial for perfusionists and patients to include hand-cranking practice in periodic extracorporeal circulation crisis management drills because a drill allows perfusionists to mentally rehearse the procedures should such a crisis occur.

Uniform Distribution of Yttrium and Heavy Rare Earth Elements in Round Top Mountain Rhyolite Deposit , Sierra Blanca Texas, USA: Data, Significance, and Origin

NASA Astrophysics Data System (ADS)

Pingitore, N. E., Jr.; Clague, J. W.; Gorski, D.

2014-12-01

The Round Top Mountain peraluminous rhyolite, exposed at the surface in Sierra Blanca, Hudspeth County, west Texas, USA, is enriched in yttrium and heavy rare earth elements (YHREEs). Other potentially valuable elements in the deposit include Be, Li, U, Th, Sn, F, Nb, and Ta. Texas Rare Earth Resources Corp. proposes to extract the YHREEs from the host mineral variety yttrofluorite by inexpensive heap leaching with dilute sulfuric acid, which also releases some of the Be, Li, U, F, and Th from other soluble minor minerals. Data: Feldspars and quartz comprise 90-95% of the rhyolite, with pheonocrysts of up to 250 microns set in an aphanitic matrix that hosts the typically sub-micron target yttrofluorite. Reverse circulation cuttings from some 100 drill holes, two drill cores, and outcrop and trench observations suggest striking physical homogeneity through this billion-plus ton surface-exposed laccolith, about 1200 feet high and a mile in diameter (375 x 1600 m). Gray to pink, and other minor hues, color variation derives from magnetite—hematite redox reaction. Plots of Y, 13 REEs, U, Th, and Nb analyses from over 1500 samples collected from 64 drill holes (color codes in figure) exhibit remarkably little variation in the concentration of these elements with geographic position or depth within the laccolith. Importance: Uniform mineralization grades help insure against the mining production surprises often associated with vein deposits and heterogeneous open pit deposits. At Round Top, mine feedstock can be relatively constant over the life of the mine (multiple decades), so the mechanical mining process can be optimized early on and not need expensive alterations later. Likewise, the chemical and physical parameters of the heap leach can be perfected. The sensitive and expensive process of extraction of elements and element groups from the pregnant leach solution and purification also can be optimized. Origin: The remarkable homogeneity of the YHREE distribution through the laccolith suggest YHREE and associated mineralization from a late-stage fluorine vapor generated within the magma in situ, rather than from injection of a F-rich fluid from an external source. The micron-scale cavities that produce up to 5% original porosity in the rhyolite may be nano-analogues of the cavities associated with granite pegmatites.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eichelberger, J.C.

Magmatic activity, and particularly silicic magmatic activity, is the fundamental process by which continental crust forms and evolves. The transport of magma from deep crustal reservoirs to the surface is a neglected but important aspect of magmatic phenomena. It encompasses problems of eruptive behavior, hydrothermal circulation, and ore deposition, and must be understood in order to properly interpret deeper processes. Drilling provides a means for determining the relationship of shallow intrusive processes to eruption processes at young volcanoes where eruptions are best understood. Drilling also provides a means for directly observing the processes of heat and mass transfer by whichmore » recently emplaced intrusions approach equilibrium with their new environment. Drilling in the Inyo Chain, a 600-year-old chain of volcanic vents in California, has shown the close relationship of silicic eruption to shallow dike emplacement, the control of eruptive style by shallow porous-flow degassing, the origin of obsidian by welding, the development of igneous zonation by viscosity segregation, and the character and size of conduits in relation to well-understood magmatic and phreatic eruptions. 36 refs., 9 figs.« less

Mechanical circulator for elastic waves by using the nonreciprocity of flexible rotating rings

NASA Astrophysics Data System (ADS)

Beli, Danilo; Silva, Priscilla Brandão; Arruda, José Roberto de França

2018-01-01

Circulators have a wide range of applications in wave manipulation. They provide a nonreciprocal response by breaking the time-reversal symmetry. In the mechanical field, nonlinear isolators and ferromagnetic circulators can be used for this objective. However, they require high power and high volumes. Herein, a flexible rotating ring is used to break the time-reversal symmetry as a result of the combined effect of Coriolis acceleration and material damping. Complete asymmetry of oscillating and evanescent components of wavenumbers is achieved. The elastic ring produces a nonreciprocal response that is used to design a three port mechanical circulator. The rotational speed for maximum transmission in one port and isolation in the other one is determined using analytical equations. A spectral element formulation is used to compute the complex dispersion diagrams and the forced response. Waveguides that support longitudinal and flexural waves are investigated. In this case, the ring nonreciprocity is modulated by the waveguide reciprocal response and the transmission coefficients can be affected. The proposed device is compact, nonferromagnetic, and may open new directions for elastic wave manipulation.

Indomethacin Inhibits Circulating PGE2 and Reverses Postexercise Suppression of Natural Killer Cell Activity

DTIC Science & Technology

1999-01-01

after the oral administration of a placebo, the PG inhibitor indomethacin (75 mg/day for 5 days), or naltrexone (reported elsewhere). Circulating...which blocks PGE2 biosynthe- sis via inhibition of cyclooxygenase activity (57). Maxi- mal suppression of PG production occurs with doses between 50...and 150 mg (1). In addition to the indepen- dent effects of PGE2 on NKCA, low circulating levels of PGE2 can synergize with endogenous glucocorticoids

Active Upper-atmosphere Chemistry and Dynamics from Polar Circulation Reversal on Titan

NASA Technical Reports Server (NTRS)

Teanby, Nicholas A.; Irwin, Patrick Gerard Joseph; Nixon, Conor A.; DeKok, Remco; Vinatier, Sandrine; Coustenis, Athena; Sefton-Nash, Elliot; Calcutt, Simon B.; Flasar, Michael F.

2012-01-01

Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-atmosphere circulation has been thought to lie at an altitude of 450 to 500 kilometres, where there is a layer of haze that appears to be separated from the main haze deck. This 'detached' haze was previously explained as being due to the colocation of peak haze production and the limit of dynamical transport by the circulation's upper branch. Herewe report a build-up of trace gases over the south pole approximately two years after observing the 2009 post-equinox circulation reversal, from which we conclude that middle-atmosphere circulation must extend to an altitude of at least 600 kilometres. The primary drivers of this circulation are summer-hemisphere heating of haze by absorption of solar radiation and winter-hemisphere cooling due to infrared emission by haze and trace gases; our results therefore imply that these effects are important well into the thermosphere (altitudes higher than 500 kilometres). This requires both active upper-atmosphere chemistry, consistent with the detection of high-complexity molecules and ions at altitudes greater than 950 kilometres, and an alternative explanation for the detached haze, such as a transition in haze particle growth from monomers to fractal structures.

Intraplate volcanism of the Western Pacific: New insights from geological and geophysical observations in the Pigafetta Basin

NASA Astrophysics Data System (ADS)

Stadler, Timothy J.

Understanding intraplate volcanism is a key to deciphering the Earth's magmatic history. One of the largest intraplate volcanic events occurred during the mid Cretaceous, roughly 75 to 125 Ma in the western Pacific. To investigate the origin and effects of this volcanism on various Earth systems, we present the first comprehensive study of volcanism in the Pigafetta Basin using seismic surveys, magnetic and gravity modeling, and Ocean Drilling Program drill core and well log data from Site 801. Our results show that intraplate volcanism in the Pigafetta Basin coincides with the rest of the western Pacific, supporting the plumelets scenario for the origin of intraplate volcanism during the mid Cretaceous volcanic event. We also discover that the late stage volcanism does not overprint the original ocean crust in the Pigafetta Basin, and hence, marine magnetic anomalies recorded in the Jurassic basement are preserved. Also, the formerly identified Rough Smooth Boundary (RSB) is indistinguishable from any other rough-smooth topographic boundaries throughout the survey area suggesting that the RSB is unlikely to be a Cretaceous sill-Jurassic basement boundary. Lastly, the apparent ages and spatial distribution of volcanic features suggests a dynamic history of hydrothermal circulation in the Pigafetta Basin, indicating that hydrothermal circulation was ongoing well past 100 Ma.

Intraplate volcanism of the western Pacific: New insights from geological and geophysical observations in the Pigafetta Basin

NASA Astrophysics Data System (ADS)

Stadler, Timothy J.; Tominaga, Masako

2015-09-01

Understanding intraplate volcanism is a key to deciphering the Earth's magmatic history. One of the largest intraplate volcanic events occurred during the mid-Cretaceous, roughly 75-125 Ma in the western Pacific. To investigate the origin of this volcanism we present the first comprehensive study of volcanism in the Pigafetta Basin using seismic surveys, magnetic and gravity modeling, and Ocean Drilling Program (ODP) drill core and well log data from Site 801. Our results show that intraplate volcanism in the Pigafetta Basin coincides with the rest of the western Pacific seamount provinces, supporting the previously suggested plumelets scenario for the origin of intraplate volcanism during the mid-Cretaceous volcanic events. Our magnetic modeling suggests that the late-stage volcanism does not overprint the remanant magnetization acquired by the Jurassic ocean crust in the Pigafetta Basin, and hence, marine magnetic anomalies recorded in the Jurassic basement are preserved. Also, the formerly identified Rough-Smooth Boundary (RSB) is indistinguishable from any other rough-smooth topographic boundaries throughout the survey area suggesting that the RSB is unlikely to be a Cretaceous sill-Jurassic basement boundary. Lastly, the apparent ages and spatial distribution of volcanic features suggests a dynamic history of hydrothermal circulation in the Pigafetta Basin, indicating that hydrothermal circulation was ongoing well past 100 Ma.

40Ar/39Ar Dating of the Brunhes-Matuyama Geomagnetic Field Reversal.

PubMed

Baksi, A K; Hsu, V; McWilliams, M O; Farrar, E

1992-04-17

Magnetostratigraphic studies are widely used in conjunction with the geomagnetic polarity time scale (GPTS) to date events in the range 0 to 5 million years ago. A critical tie point on the GPTS is the potassium-argon age of the most recent (Brunhes-Matuyama) geomagnetic field reversal. Astronomical values for the forcing frequencies observed in the oxygen isotope record in Ocean Drilling Project site 677 suggest that the age of this last reversal is 780 ka (thousand years ago), whereas the potassium-argon-based estimate is 730 ka. Results from 4039; Ar incremental heating studies on a series of lavas from Maui that straddle the Brunhes-Matuyama reversal give an age of 783 + 11 ka, in agreement with the astronomically derived value. The astronomically based technique appears to be a viable tool for dating young sedimentary sequences.

What an option is worth for an exploration opportunity

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKay, J.A.; Lerche, I.

1995-12-25

The reason that a corporation might want to take an option on an opportunity is to wait until more information becomes available before committing to the decision to drill. For instance, in a situation where an opportunity is one of the first prospects in a new play trend, there is often very little known (as opposed to surmised) about the potential gain, and the chances of success are also often poorly determined. Thus, until the estimates of costs, gains, and success chances are firmed up in the future by drilling information from other operators, the corporation would prefer to holdmore » off on the decision to drill a particular prospect. Recently Dixit and Pindyck have persuasively argued qualitatively that an options approach should be taken to capital investment in any business field because, opportunities are options--rights but not obligations to take some action in the future and, as soon as you begin thinking of investment opportunities as options, the premise (that investment decisions can be reversed if conditions change or, if they cannot be reversed, that they are now-or-never propositions) changes. Irreversibility, uncertainty, and the choice of timing alter the investment decision in critical ways. From an oil industry perspective Dixit and Pindyck eloquently provide the rationale for considering an option position rather than dealing only with net present value considerations. The ability to calculate the worth of an option to a hydrocarbon exploration opportunity is what this article is about.« less

Real Time Mud Gas Logging During Drilling of DFDP-2B

NASA Astrophysics Data System (ADS)

Mathewson, L. A.; Toy, V.; Menzies, C. D.; Zimmer, M.; Erzinger, J.; Niedermann, S.; Cox, S.

2015-12-01

The Deep Fault Drilling Project (DFDP) aims to improve our understanding of the Alpine Fault Zone, a tectonically active mature fault system in New Zealand known to rupture in large events, by deep scientific drilling. The borehole DFDP-2B approached the Alpine Fault at depth, reaching a final depth of 892 m (820 m true vertical depth). Online gas analysis (OLGA) while drilling tracked changes in the composition of gases extracted from the circulating drill mud. The composition of fluids from fault zones can provide information about their origins, flow rates and -paths, fluid-rock interactions along these paths, and the permeability structure of the faulted rock mass. Apart from an atmospheric input, the gases in drilling mud derive from the pore space of rock, crushed at the drill bit, and from permeable layers intersected by the borehole. The rapid formation of mud wall cake seals the borehole from further fluid inflow, hence formation-derived gases enter mostly at the depth of the drill bit. OLGA analyses N2, O2, Ar, CO2, CH4, He, and H2 on a mass spectrometer, hydrocarbons CH4, C2H6, C3H8, i-C4H10, and n-C4H10 on a gas chromatograph, and Rn using a lucas-cell detector. Gas was sampled for offline analyses on noble gas and stable isotopes to complement the OLGA dataset. The principle formation-derived gases found in drilling mud during drilling of DFDP-2 were CO2 and CH4, with smaller component of H2 and He2. High radon activity is interpreted to reflect intervals of active fluid flow through highly fractured and faulted rock. 3He/4He values in many samples were extremely air-contaminated, i.e. there was almost no excess of non-atmospheric He. The 3He/4He values measured at 236 m and 610 m, which are the only analyses with uncertainties <100%, are very similar to those measured in hot springs along the Alpine Fault, e.g. Fox River (0.64 Ra), Copland (0.42 Ra), Lower Wanganui (0.81 Ra). We will compare these data to those gathered using OLGA and discuss the implications.

A 3-D wellbore simulator (WELLTHER-SIM) to determine the thermal diffusivity of rock-formations

NASA Astrophysics Data System (ADS)

Wong-Loya, J. A.; Santoyo, E.; Andaverde, J.

2017-06-01

Acquiring thermophysical properties of rock-formations in geothermal systems is an essential task required for the well drilling and completion. Wellbore thermal simulators require such properties for predicting the thermal behavior of a wellbore and the formation under drilling and shut-in conditions. The estimation of static formation temperatures also needs the use of these properties for the wellbore and formation materials (drilling fluids and pipes, cements, casings, and rocks). A numerical simulator (WELLTHER-SIM) has been developed for modeling the drilling fluid circulation and shut-in processes of geothermal wellbores, and for the in-situ determination of thermal diffusivities of rocks. Bottomhole temperatures logged under shut-in conditions (BHTm), and thermophysical and transport properties of drilling fluids were used as main input data. To model the thermal disturbance and recovery processes in the wellbore and rock-formation, initial drilling fluid and static formation temperatures were used as initial and boundary conditions. WELLTHER-SIM uses these temperatures together with an initial thermal diffusivity for the rock-formation to solve the governing equations of the heat transfer model. WELLTHER-SIM was programmed using the finite volume technique to solve the heat conduction equations under 3-D and transient conditions. Thermal diffusivities of rock-formations were inversely computed by using an iterative and efficient numerical simulation, where simulated thermal recovery data sets (BHTs) were statistically compared with those temperature measurements (BHTm) logged in some geothermal wellbores. The simulator was validated using a well-documented case reported in the literature, where the thermophysical properties of the rock-formation are known with accuracy. The new numerical simulator has been successfully applied to two wellbores drilled in geothermal fields of Japan and Mexico. Details of the physical conceptual model, the numerical algorithm, and the validation and application results are outlined in this work.

Variations in Mediterranean-Atlantic exchange across the late Pliocene climate transition

NASA Astrophysics Data System (ADS)

García-Gallardo, Ángela; Grunert, Patrick; Piller, Werner E.

2018-03-01

Mediterranean-Atlantic exchange through the Strait of Gibraltar plays a significant role in the global ocean-climate dynamics in two ways. On one side, the injection of the saline and warm Mediterranean Outflow Water (MOW) contributes to North Atlantic deep-water formation. In return, the Atlantic inflow is considered a sink of less saline water for the North Atlantic Ocean. However, while the history of MOW is the focus of numerous studies, the Pliocene Atlantic inflow has received little attention so far. The present study provides an assessment of the Mediterranean-Atlantic exchange with a focus on the Atlantic inflow strength and its response to regional and global climate from 3.33 to 2.60 Ma. This time interval comprises the mid-Pliocene warm period (MPWP; 3.29-2.97 Ma) and the onset of the Northern Hemisphere glaciation (NHG). For this purpose, gradients in surface δ18O records of the planktonic foraminifer Globigerinoides ruber between the Integrated Ocean Drilling Program (IODP) Hole U1389E (Gulf of Cádiz) and Ocean Drilling Program (ODP) Hole 978A (Alboran Sea) have been evaluated. Interglacial stages and warm glacials of the MPWP revealed steep and reversed (relative to the present) W-E δ18O gradients suggesting a weakening of Mediterranean-Atlantic exchange likely caused by high levels of relative humidity in the Mediterranean region. In contrast, periods of stronger inflow are indicated by flat δ18O gradients due to more intense arid conditions during the severe glacial Marine Isotope Stage (MIS) M2 and the initiation of NHG (MIS G22, G14, G6-104). Intensified Mediterranean-Atlantic exchange in cold periods is linked to the occurrence of ice-rafted debris (IRD) at low latitudes and a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Our results thus suggest the development of a negative feedback between AMOC and exchange rates at the Strait of Gibraltar in the latest Pliocene as it has been proposed for the late Quaternary.

Core cooling under accident conditions at the high flux beam reactor (HFBR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tichler, P.; Cheng, L.; Fauske, H.

In certain accident scenarios, e.g. loss of coolant accidents (LOCA) all forced flow cooling is lost. Decay heating causes a temperature increase in the core coolant and the resulting thermal buoyancy causes a reversal of the flow direction to a natural circulation mode. Although there was experimental evidence during the reactor design period (1958--1963) that the heat removal capacity in the fully developed natural circulation cooling mode was relatively high, it was not possible to make a confident prediction of the heat removal capacity during the transition from downflow to natural circulation. In a LOCA scenario where even limited fuelmore » damage occurs and natural circulation is established, fission product gases could be carried from the damaged fuel by steam into areas where operator access is required to maintain the core in a coolable configuration. This would force evacuation of the building and lead to extensive core damage. As a result the HFBR was shut down by the Department of Energy (DOE) and an extensive review of the HFBR was initiated. In an effort to address this issue BNL developed a model designed to predict the heat removal limit during flow reversal that was found to be in good agreement with the test results. Currently a thermal-hydraulic test program is being developed to provide a more realistic and defensible estimate of the flow reversal heat removal limit so that the reactor power level can be increased.« less

Magma-Hydrothermal Transition: Basalt Alteration at Supercritical Conditions in Drill Core from Reykjanes, Iceland, Iceland Deep Drilling Project.

NASA Astrophysics Data System (ADS)

Zierenberg, R. A.; Fowler, A. P.; Schiffman, P.; Fridleifsson, G. Ó.; Elders, W. A.

2017-12-01

The Iceland Deep Drilling Project well IDDP-2, drilled to 4,659 m in the Reykjanes geothermal system, the on-land extension of the Mid Atlantic Ridge, SW Iceland. Drill core was recovered, for the first time, from a seawater-recharged, basalt-hosted hydrothermal system at supercritical conditions. The well has not yet been allowed to heat to in situ conditions, but temperature and pressure of 426º C and 340 bar was measured at 4500 m depth prior to the final coring runs. Spot drill cores were recovered between drilling depths of 3648.00 m and 4657.58 m. Analysis of the core is on-going, but we present the following initial observations. The cored material comes from a basaltic sheeted dike complex in the brittle-ductile transition zone. Felsic (plagiogranite) segregation veins are present in minor amounts in dikes recovered below 4300 m. Most core is pervasively altered to hornblende + plagioclase, but shows only minor changes in major and minor element composition. The deepest samples record the transition from the magmatic regime to the presently active hydrothermal system. Diabase near dike margins has been locally recrystallized to granoblastic-textured orthopyroxene-clinopyroxe-plagioclase hornfels. High temperature hydrothermal alteration includes calcic plagioclase (up to An100) and aluminous hornblende (up to 11 Wt. % Al2O3) locally intergrown with hydrothermal biotite, clinopyroxene, orthopyroxene and/or olivine. Hydrothermal olivine is iron-rich (Mg # 59-64) compared to expected values for igneous olivine. Biotite phenocrysts in felsic segregation veins have higher Cl and Fe compared to hydrothermal biotites. Orthopyroxene-clinopyroxene pairs in partially altered quench dike margins give temperature of 955° to 1067° C. Orthopyroxene-clinopyroxene pairs from hornfels and hydrothermal veins and replacements give temperature ranging from 774° to 888° C. Downhole fluid sampling is planned following thermal equilibration of the drill hole. Previous work has suggested that the Reykjanes geothermal system has been active since the last glaciation, 10ka. No shallow melt bodies have been detected on the Reykjanes Peninsula suggesting that hydrothermal circulation typical of black smoker systems can be sustained with out a magmatic heat source.

Neogene deformation in the West Antarctic Rift in the McMurdo Sound region from studies of the ANDRILL and Cape Roberts drill cores

NASA Astrophysics Data System (ADS)

Paulsen, T. S.; Wilson, T. J.; Jarrard, R. D.; Millan, C.; Saddler, D.; Läufer, A.; Pierdominici, S.

2010-12-01

Seismic studies indicate that the West Antarctic rift system records at least two distinct periods of Cenozoic rifting (Paleogene and Neogene) within the western Ross Sea. Natural fracture data from ANDRILL and Cape Roberts drill cores are revealing a picture of the geodynamic patterns associated with these rifting episodes. Kinematic indicators along faults recovered in drill cores document dominant normal faulting, although reverse and strike-slip faults are also present. Ongoing studies of mechanically twinned calcite in veins recovered in the drill cores yield predominantly vertical shortening strains with horizontal extension, consistent with a normal fault regime. In the Cape Roberts Project drill core, faults of inferred Oligocene age document a dominant NNE maximum horizontal stress associated with Paleogene rifting within the Victoria Land Basin. The NNE maximum horizontal stress at Cape Roberts is at an oblique angle to Transantarctic Mountain front, and consistent with previous interpretations invoking Cenozoic dextral transtensional shear along the boundary. In the ANDRILL SMS (AND-2A) drill core, faults and veins presumably associated with Neogene rifting document a dominant NNW to NE faulting of an expanded Lower Miocene section, although subsidiary WNW faulting is also present within the upper sections of oriented core. In the ANDRILL MIS (AND-1B) drill core, natural fractures are consistently present through the core below c. 450 mbsf, the estimated depth of the ‘B-clino’ seismic reflector. This is consistent with the presence of seismically-detectable faults below this horizon, which record the major faulting episode associated with Neogene rifting in the Terror Rift. Sedimentary intrusions and steep veins folded by compaction indicate that deformation occurred prior to complete lithification of the strata, suggesting that deformation was at least in part coeval with deposition. Faults and associated veins intersected in the AND-1B drill core also cut Pliocene and Pleistocene strata, suggesting that deformation has continued to the recent or may perhaps ongoing.

The top of the Olduvai subchron in a high-resolution magnetostratigraphy from the West Turkana core WTK13, Hominin Sites and Paleolakes Drilling Project (HSPDP)

NASA Astrophysics Data System (ADS)

Sier, Mark; Langereis, Cor; Dupont-Nivet, Guillaume; Feibel, Craig; Jordeens, Jose; van der Lubbe, Jeroen; Beck, Catherine; Olago, Daniel; Cohen, Andrew

2017-04-01

One of the major challenges in understanding the evolution of our own species is identifying the role climate change has played in the evolution of earlier hominin species. To clarify the influence of climate, we need long and continuous high-resolution paleoclimate records, preferably obtained from hominin-bearing sediments, that are well-dated by tephro- and magnetostratigraphy and other methods. This is hindered, however, by the fact that fossil-bearing sediments are often discontinuous, and subject to weathering, which may lead to oxidation and remagnetization. To obtain fresh, unweathered sediments, the Hominin Sites and Paleolakes Drilling Project (HSPDP) collected a 216- meter core (WTK13) in 2013 from deposits of Early Pleistocene paleolake Lorenyang in the western Turkana Basin (Kenya). Here, we present the magnetostratigraphy of the core. Rock magnetic analyses reveal the presence of iron sulphides carrying the remanent magnetizations. To recover polarity orientation from the near-equatorial WTK13 core drilled at 5°N, we developed and successfully applied two independent drill-core reorientation methods taking advantage of (1) the sedimentary fabric as expressed in the Anisotropy of Magnetic Susceptibility (AMS) and (2) the occurrence of a viscous component oriented in the present day field. The reoriented directions reveal a normal to reversed polarity reversal identified as the top of the Olduvai subchron. From this excellent record, we find no evidence for the 'Vrica subchron' previously reported in the area. We suggest that outcrop-based interpretations supporting the presence of the Vrica subchron have been affected by the oxidation of iron sulphides initially present in the sediments as evident in the core record, and by subsequent remagnetization. Based on our new high-resolution magnetostratigraphy and stratigraphic markers, we provide constraints for an initial age model of the WTK13 core. We discuss the implications of the observed geomagnetic record for human evolution studies.

Laser bottom hole assembly

DOEpatents

Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

2014-01-14

There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

Content Matters: Building Vocabulary and Conceptual Understanding in the Subject Areas

ERIC Educational Resources Information Center

Greenwood, Scott

2004-01-01

This article focuses on traditional vocabulary instruction that has often had pernicious side effects: drill and kill that turned kids off to reading and word study. This trend can be reversed through careful attention to the needs and predilections of students as well as conspicuous consideration of the ramifications of time-cost. Here, the…

Reaction of Rhyolitic Magma to its Interception by the IDDP-1 Well, Krafla, 2009

NASA Astrophysics Data System (ADS)

Saubin, É.; Kennedy, B.; Tuffen, H.; Villeneuve, M.; Watson, T.; Nichols, A. R.; Schipper, I.; Cole, J. W.; Mortensen, A. K.; Zierenberg, R. A.

2017-12-01

The unexpected encounter of rhyolitic magma during IDDP-1 geothermal borehole drilling at Krafla, Iceland in 2009, temporarily created the world's hottest geothermal well. This allowed new questions to be addressed. i) How does magma react to drilling? ii) Are the margins of a magma chamber suitable for long-term extraction of supercritical fluids? To investigate these questions, we aim to reconstruct the degassing and deformation behaviour of the enigmatic magma by looking for correlations between textures in rhyolitic material retrieved from the borehole and the recorded drilling data. During drilling, difficulties were encountered in two zones, at 2070 m and below 2093 m depth. Drilling parameters are consistent with the drill bit encountering a high permeability zone and the contact zone of a magma chamber, respectively. Magma was intercepted three times between 2101-2104.4 m depth, which culminated in an increase in standpipe pressure followed by a decrease in weight on bit interpreted as representing the ascent of magma within the borehole. Circulation returned one hour after the last interception, carrying cuttings of glassy particles, felsite with granophyre and contaminant clasts from drilling, which were sampled as a time-series for the following 9 hours. The nature of glassy particles in this time-series varied through time, with a decrease in the proportion of vesicular clasts and a commensurate increase in dense glassy clasts, transitioning from initially colourless to brown glass. Componentry data show a sporadic decrease in felsite (from 34 wt. %), an increase in glassy particles during the first two hours (from 63 wt. % to 94 wt. %) and an increase in contaminant clasts towards the end of the cutting retrieval period. These temporal variations are probably related to the magma body architecture and interactions with the borehole. Transition from vesicular to dense clasts suggests a change in the degassing process that could be related to an early degassing phase caused by drilling-induced decompressions followed by a fast ascent after the last magma interception. Additional data in terms of shape of clasts, vesicularity, density and water content within glassy particles will link textural data to drilling history in order to investigate degassing history, origin of clasts and quenching pressure.

Collapse of the 2017 Winter Beaufort High: A Response to Thinning Sea Ice?

NASA Astrophysics Data System (ADS)

Moore, G. W. K.; Schweiger, A.; Zhang, J.; Steele, M.

2018-03-01

The winter Arctic atmosphere is under the influence of two very different circulation systems: extratropical cyclones travel along the primary North Atlantic storm track from Iceland toward the eastern Arctic, while the western Arctic is characterized by a quasi-stationary region of high pressure known as the Beaufort High. The winter (January through March) of 2017 featured an anomalous reversal of the normally anticyclonic surface winds and sea ice motion in the western Arctic. This reversal can be traced to a collapse of the Beaufort High as the result of the intrusion of low-pressure systems from the North Atlantic, along the East Siberian Coast, into the Arctic Basin. Thin sea ice as the result of an extremely warm autumn (October through December) of 2016 contributed to the formation of an anomalous thermal low over the Barents Sea that, along with a northward shift of the tropospheric polar vortex, permitted this intrusion. The collapse of the Beaufort High during the winter of 2017 was associated with simultaneous 2-sigma sea level pressure, surface wind, and sea ice circulation anomalies in the western Arctic. As the Arctic sea ice continues to thin, such reversals may become more common and impact ocean circulation, sea ice, and biology.

Reversible elementary cellular automaton with rule number 150 and periodic boundary conditions over 𝔽p

NASA Astrophysics Data System (ADS)

Martín Del Rey, A.; Rodríguez Sánchez, G.

2015-03-01

The study of the reversibility of elementary cellular automata with rule number 150 over the finite state set 𝔽p and endowed with periodic boundary conditions is done. The dynamic of such discrete dynamical systems is characterized by means of characteristic circulant matrices, and their analysis allows us to state that the reversibility depends on the number of cells of the cellular space and to explicitly compute the corresponding inverse cellular automata.

Simulating pathways of subsurface oil in the Faroe-Shetland Channel using an ocean general circulation model.

PubMed

Main, C E; Yool, A; Holliday, N P; Popova, E E; Jones, D O B; Ruhl, H A

2017-01-15

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe-Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here, an ocean general circulation model was used with a particle tracking algorithm to assess temporal variability of the oil-plume distribution from a deep-sea oil well blowout in the FSC. The drift of particles was first tracked for one year following release. Then, ambient model temperatures were used to simulate temperature-mediated biodegradation, truncating the trajectories of particles accordingly. Release depth of the modeled subsurface plumes affected both their direction of transport and distance travelled from their release location, and there was considerable interannual variability in transport. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buce, W.F.

Heretofore methods of preventing lost circulation in a formation zone during drilling operations, for example, involve pumping loss circulation material into the zone. These materials were wedged into the pores and indices of the formation with fluid pressure. In large pathways, these methods were often unsuccessful owing to the fact that the material could not be maintained at their desired location. By this method, a polymerizable material capable of forming hard, porous relatively insoluble popcorn polymers is placed in the formation zone desired to be sealed. The material is there maintained under polymerization conditions for a time sufficient to polymerizemore » in situ at least a portion of the material and restrict fluid pathways through the zone without exerting a force on the formation zone of a magnitude sufficient for fracturing it. (10 claims)« less

Learning by strategies and learning by drill--evidence from an fMRI study.

PubMed

Delazer, M; Ischebeck, A; Domahs, F; Zamarian, L; Koppelstaetter, F; Siedentopf, C M; Kaufmann, L; Benke, T; Felber, S

2005-04-15

The present fMRI study investigates, first, whether learning new arithmetic operations is reflected by changing cerebral activation patterns, and second, whether different learning methods lead to differential modifications of brain activation. In a controlled design, subjects were trained over a week on two new complex arithmetic operations, one operation trained by the application of back-up strategies, i.e., a sequence of arithmetic operations, the other by drill, i.e., by learning the association between the operands and the result. In the following fMRI session, new untrained items, items trained by strategy and items trained by drill, were assessed using an event-related design. Untrained items as compared to trained showed large bilateral parietal activations, with the focus of activation along the right intraparietal sulcus. Further foci of activation were found in both inferior frontal gyri. The reverse contrast, trained vs. untrained, showed a more focused activation pattern with activation in both angular gyri. As suggested by the specific activation patterns, newly acquired expertise was implemented in previously existing networks of arithmetic processing and memory. Comparisons between drill and strategy conditions suggest that successful retrieval was associated with different brain activation patterns reflecting the underlying learning methods. While the drill condition more strongly activated medial parietal regions extending to the left angular gyrus, the strategy condition was associated to the activation of the precuneus which may be accounted for by visual imagery in memory retrieval.

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2012 CFR

2012-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2013 CFR

2013-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2014 CFR

2014-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

Preliminary paleomagnetic results from the Coyote Creek Outdoor Classroom drill hole, Santa Clara Valley, California

USGS Publications Warehouse

Mankinen, Edward A.; Wentworth, Carl M.

2003-01-01

Paleomagnetic samples were obtained from cores taken during the drilling of a research well along Coyote Creek in San Jose, California, in order to use the geomagnetic field behavior recorded in those samples to provide age constraints for the sediment encountered. The well reached a depth of 308 meters and material apparently was deposited largely (entirely?) during the Brunhes Normal Polarity Chron, which lasted from 780 ka to the present time. Three episodes of anomalous magnetic inclinations were recorded in parts of the sedimentary sequence; the uppermost two we correlate to the Mono Lake (~30 ka) geomagnetic excursion and 6 cm lower, tentatively to the Laschamp (~45 ka) excursion. The lowermost anomalous interval occurs at 305 m and consists of less than 10 cm of fully reversed inclinations underlain by 1.5 m of normal polarity sediment. This lower anomalous interval may represent either the Big Lost excursion (~565 ka) or the polarity transition at the end of the Matuyama Reversed Polarity Chron (780 ka). The average rates of deposition for the Pleistocene section in this well, based on these two alternatives, are approximately 52 or 37 cm/kyr, respectively.

Comparative analysis of a jack-up drilling unit with different leg systems

NASA Astrophysics Data System (ADS)

Ren, Xiangang; Bai, Yong; Jia, Lusheng

2012-09-01

The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters. As the most pivotal component of the jack-up unit, the leg system can directly affect the global performance of a jack-up unit. Investigation shows that there are three kinds of leg structure forms in the world now: the reverse K, X, and mixing types. In order to clarify the advantage and defects of each one, as well as their effect on the global performance of the jack-up unit, this paper commenced to study performance targets of a deepwater jack-up unit with different leg systems (X type, reverse K type, and mixing type). In this paper a typical leg scantling dimension and identical external loads were selected, detailed finite element snalysis (FEA) models were built to simulate the jack-up unit's structural behavior, and the multi-point constraint (MPC) element together with the spring element was used to deal with the boundary condition. Finally, the above problems were solved by comparative analysis of their main performance targets (including ultimate static strength, dynamic response, and weight).

Industrial food processing and space heating with geothermal heat. Final report, February 16, 1979-August 31, 1982

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunze, J.F.; Marlor, J.K.

1982-08-01

A competitive aware for a cost sharing program was made to Madison County, Idaho to share in a program to develop moderate-to-low temperature geothermal energy for the heating of a large junior college, business building, public shcools and other large buildings in Rexburg, Idaho. A 3943 ft deep well was drilled at the edge of Rexburg in a region that had been probed by some shallower test holes. Temperatures measured near the 4000 ft depth were far below what was expected or needed, and drilling was abandoned at that depth. In 1981 attempts were made to restrict downward circulation intomore » the well, but the results of this effort yielded no higher temperatures. The well is a prolific producer of 70/sup 0/F water, and could be used as a domestic water well.« less

Research on Impact Stress and Fatigue Simulation of a New Down-to-the-Hole Impactor Based on ANSYS

NASA Astrophysics Data System (ADS)

Wu, Tao; Wang, Wei; Yao, Aiguo; Li, Yongbo; He, Wangyong; Fei, Dongdong

2018-06-01

In the present work, a down-to-the-hole electric hammer driven by linear motor is reported for drilling engineering. It differs from the common hydraulic or pneumatic hammers in that it can be applied to some special occasions without circulating medium due to its independence of the drilling fluid. The impact stress caused by the reciprocating motion between stator and rotor and the fatigue damage in key components of linear motor are analyzed by the ANSYS Workbench software and 3D model. Based on simulation results, the hammer's structure is optimized by using special sliding bearing, increasing the wall thickness of key and multilayer buffer gasket. Fatigue life and coefficient issues of the new structure are dramatically improved. However buffer gasket reduces the impactor's energy, different bumper structure effect on life improving and energy loss have also been elaborated.

Fracture Gap Reduction With Variable-Pitch Headless Screws.

PubMed

Roebke, Austin J; Roebke, Logan J; Goyal, Kanu S

2018-04-01

Fully threaded, variable-pitch, headless screws are used in many settings in surgery and have been extensively studied in this context, especially in regard to scaphoid fractures. However, it is not well understood how screw parameters such as diameter, length, and pitch variation, as well as technique parameters such as depth of drilling, affect gap closure. Acutrak 2 fully threaded variable-pitch headless screws of various diameters (Standard, Mini, and Micro) and lengths (16-28 mm) were inserted into polyurethane blocks of "normal" and "osteoporotic" bone model densities using a custom jig. Three drilling techniques (drill only through first block, 4 mm into second block, or completely through both blocks) were used. During screw insertion, fluoroscopic images were taken and later analyzed to measure gap reduction. The effect of backing the screw out after compression was evaluated. Drilling at least 4 mm past the fracture site reduces distal fragment push-off compared with drilling only through the proximal fragment. There were no significant differences in gap closure in the normal versus the osteoporotic model. The Micro screw had a smaller gap closure than both the Standard and the Mini screws. After block contact and compression with 2 subsequent full forward turns, backing the screw out by only 1 full turn resulted in gapping between the blocks. Intuitively, fully threaded headless variable-pitch screws can obtain compression between bone fragments only if the initial gap is less than the gap closed. Gap closure may be affected by drilling technique, screw size, and screw length. Fragment compression may be immediately lost if the screw is reversed. We describe characteristics of variable-pitch headless screws that may assist the surgeon in screw choice and method of use. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Slim hole drilling and testing strategies

NASA Astrophysics Data System (ADS)

Nielson, Dennis L.; Garg, Sabodh K.; Goranson, Colin

2017-12-01

The financial and geologic advantages of drilling slim holes instead of large production wells in the early stages of geothermal reservoir assessment has been understood for many years. However, the practice has not been fully embraced by geothermal developers. We believe that the reason for this is that there is a poor understanding of testing and reservoir analysis that can be conducted in slim holes. In addition to reservoir engineering information, coring through the cap rock and into the reservoir provides important data for designing subsequent production well drilling and completion. Core drilling requires significantly less mud volume than conventional rotary drilling, and it is typically not necessary to cure lost circulation zones (LCZ). LCZs should be tested by either production or injection methods as they are encountered. The testing methodologies are similar to those conducted on large-diameter wells; although produced and/or injected fluid volumes are much less. Pressure, temperature and spinner (PTS) surveys in slim holes under static conditions can used to characterize temperature and pressure distribution in the geothermal reservoir. In many cases it is possible to discharge slim holes and obtain fluid samples to delineate the geochemical properties of the reservoir fluid. Also in the latter case, drawdown and buildup data obtained using a downhole pressure tool can be employed to determine formation transmissivity and well properties. Even if it proves difficult to discharge a slim hole, an injection test can be performed to obtain formation transmissivity. Given the discharge (or injection) data from a slimhole, discharge properties of a large-diameter well can be inferred using wellbore modeling. Finally, slim hole data (pressure, temperature, transmissivity, fluid properties) together with reservoir simulation can help predict the ability of the geothermal reservoir to sustain power production.

Circulating type 1 vaccine-derived poliovirus may evolve under the pressure of adenosine deaminases acting on RNA.

PubMed

Liu, Yanhan; Ma, Tengfei; Liu, Jianzhu; Zhao, Xiaona; Cheng, Ziqiang; Guo, Huijun; Xu, Ruixue; Wang, Shujing

2015-01-01

Poliovirus, the causative agent of poliomyelitis, is a human enterovirus and member of the Picornaviridae family. An effective live-attenuated poliovirus vaccine strain (Sabin 1) has been developed and has protected humans from polio. However, a few cases of vaccine virulence reversion have been documented in several countries. For instance, circulating type 1 vaccine-derived poliovirus is a highly pathogenic poliovirus that evolved from an avirulent strain, but the mechanism by which vaccine strains undergo reversion remains unclear. In this study, vaccine strains exhibited A to G/U to C and G to A/C to U hypermutations in the reversed evolution of Sabin 1. Furthermore, the mutation ratios of U to C and C to U were higher than those of other mutation types. Dinucleotide editing context was then analyzed. Results showed that A to G and U to C mutations exhibited preferences similar to adenosine deaminases acting on RNA (ADAR). Hence, ADARs may participate in poliovirus vaccine evolution.

Brain Gain or Brain Circulation? U.S. Doctoral Recipients Returning to South Korea

ERIC Educational Resources Information Center

Lee, Jenny J.; Kim, Dongbin

2010-01-01

This study explored the reasons for current reverse mobility patterns in South Korea and how the country benefits from returning U.S. doctoral recipients in the forms of brain gain and brain circulation. Based on interviews of Korean faculty who studied in the U.S., this study found that while the political economy might help to explain why Korean…

Reverse transendothelial cell migration in inflammation: to help or to hinder?

PubMed

Burn, Thomas; Alvarez, Jorge Ivan

2017-05-01

The endothelium provides a strong barrier separating circulating blood from tissue. It also provides a significant challenge for immune cells in the bloodstream to access potential sites of infection. To mount an effective immune response, leukocytes traverse the endothelial layer in a process known as transendothelial migration. Decades of work have allowed dissection of the mechanisms through which immune cells gain access into peripheral tissues, and subsequently to inflammatory foci. However, an often under-appreciated or potentially ignored question is whether transmigrated leukocytes can leave these inflammatory sites, and perhaps even return across the endothelium and re-enter circulation. Although evidence has existed to support "reverse" transendothelial migration for a number of years, it is only recently that mechanisms associated with this process have been described. Here we review the evidence that supports both reverse transendothelial migration and reverse interstitial migration within tissues, with particular emphasis on some of the more recent studies that finally hint at potential mechanisms. Additionally, we postulate the biological significance of retrograde migration, and whether it serves as an additional mechanism to limit pathology, or provides a basis for the dissemination of systemic inflammation.

Site selection for DOE/JIP gas hydrate drilling in the northern Gulf of Mexico

USGS Publications Warehouse

Hutchinson, Deborah; Shelander, Dianna; Dai, J.; McConnell, D.; Shedd, William; Frye, Matthew; Ruppel, Carolyn D.; Boswell, R.; Jones, Emrys; Collett, Timothy S.; Rose, Kelly K.; Dugan, Brandon; Wood, Warren T.

2008-01-01

n the late spring of 2008, the Chevron-led Gulf of Mexico Gas Hydrate Joint Industry Project (JIP) expects to conduct an exploratory drilling and logging campaign to better understand gas hydrate-bearing sands in the deepwater Gulf of Mexico. The JIP Site Selection team selected three areas to test alternative geological models and geophysical interpretations supporting the existence of potential high gas hydrate saturations in reservoir-quality sands. The three sites are near existing drill holes which provide geological and geophysical constraints in Alaminos Canyon (AC) lease block 818, Green Canyon (GC) 955, and Walker Ridge (WR) 313. At the AC818 site, gas hydrate is interpreted to occur within the Oligocene Frio volcaniclastic sand at the crest of a fold that is shallow enough to be in the hydrate stability zone. Drilling at GC955 will sample a faulted, buried Pleistocene channel-levee system in an area characterized by seafloor fluid expulsion features, structural closure associated with uplifted salt, and abundant seismic evidence for upward migration of fluids and gas into the sand-rich parts of the sedimentary section. Drilling at WR313 targets ponded sheet sands and associated channel/levee deposits within a minibasin, making this a non-structural play. The potential for gas hydrate occurrence at WR313 is supported by shingled phase reversals consistent with the transition from gas-charged sand to overlying gas-hydrate saturated sand. Drilling locations have been selected at each site to 1) test geological methods and models used to infer the occurrence of gas hydrate in sand reservoirs in different settings in the northern Gulf of Mexico; 2) calibrate geophysical models used to detect gas hydrate sands, map reservoir thicknesses, and estimate the degree of gas hydrate saturation; and 3) delineate potential locations for subsequent JIP drilling and coring operations that will collect samples for comprehensive physical property, geochemical and other analyses

The double slit experiment and the time reversed fire alarm

NASA Astrophysics Data System (ADS)

Halabi, Tarek

2011-03-01

When both slits of the double slit experiment are open, closing one paradoxically increases the detection rate at some points on the detection screen. Feynman famously warned that temptation to "understand" such a puzzling feature only draws us into blind alleys. Nevertheless, we gain insight into this feature by drawing an analogy between the double slit experiment and a time reversed fire alarm. Much as closing the slit increases probability of a future detection, ruling out fire drill scenarios, having heard the fire alarm, increases probability of a past fire (using Bayesian inference). Classically, Bayesian inference is associated with computing probabilities of past events. We therefore identify this feature of the double slit experiment with a time reversed thermodynamic arrow. We believe that much of the enigma of quantum mechanics is simply due to some variation of time's arrow.

Astrochronology of a Late Oligocene to Early Miocene Magnetostratigraphy from the Northwest Atlantic

NASA Astrophysics Data System (ADS)

van Peer, T. E.; Xuan, C.; Liebrand, D.; Lippert, P. C.; Wilson, P. A.

2016-12-01

The Oligocene-Miocene Boundary is defined by the geomagnetic polarity reversal C6Cn.2n/C6Cn.2r with an astronomically tuned age of 23 Ma. For late Oligocene to early Miocene reversals, only a few records (mainly from the equatorial Pacific and South Atlantic) integrate magneto- and cyclo-stratigraphy with astronomical tuning. Reversal ages acquired from these records show differences up to 100 kyr. We report new astronomically tuned ages for reversals between 21-26.5 Ma, based on integrated palaeomagnetic and X-Ray Fluorescence (XRF) data from rapidly accumulated drift sediments (mean sedimentation rate of 2.5 cm/kyr) at Integrated Ocean Drilling Program (IODP) Site U1406 (northwest Atlantic). The natural remanence preserved in the sediments is relatively weak (especially at high demagnetisation steps) and prone to influence from measurement noise. We introduce an optimisation protocol to improve the estimation of component directions used to define the reversals. For each 1-cm interval measurement, the protocol searches for the combination of a fixed number of steps of demagnetisation data that minimises the maximum angular deviation, statistically excluding the noisy measurement steps. For the tuning, we use the logarithm of the calcium over potassium ratio ln(Ca/K) from XRF core scanning data, a proxy of carbonate content in the sediment. Spectral and wavelet analyses of the 140-m long ln(Ca/K) record highlight dominant obliquity (including the 178 and 1200 kyr modulation) and additional eccentricity forcing. Supported by preliminary stable isotope analysis on benthic foraminifera, we tuned ln(Ca/K) minima to obliquity minima and eccentricity maxima. The resulting age model yield new independent ages for all reversals between C6Ar/C6AAn to C8r/C9n. Our results are generally consistent (within an obliquity cycle) with the Ocean Drilling Program (ODP) Site 1090 age model [Billups et al., 2004], but deviate up to 80 kyr relative to ODP Site 1218 [Pälike et al., 2006] and ATNTS2004 [Lourens et al., 2004] age models. The concurrent high-fidelity reversal ages from ODP Site 1090 and IODP Site U1406 reconcile discrepancies in the early Miocene GPTS, and provide improved temporal constraints, which are critical to the study of palaeomagnetic and environmental changes of this time interval.

Applications and benefits of technology in naturally fractured, low permeability reservoirs with special emphasis on results from GRI`s devonian shale and berea sand research in the appalachian basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jochen, J.E.; Hopkins, C.W.

1993-12-31

;Contents: Naturally fractured reservoir description; Geologic considerations; Shale-specific log model; Stress profiles; Berea reasearch; Benefits analysis; Summary of technologies; Novel well test methods; Natural fracture identification; Reverse drilling; Production data analysis; Fracture treatment quality control; Novel core analysis methods; and Shale well cleanouts.

An improved method for detecting circulating microRNAs with S-Poly(T) Plus real-time PCR

PubMed Central

Niu, Yanqin; Zhang, Limin; Qiu, Huiling; Wu, Yike; Wang, Zhiwei; Zai, Yujia; Liu, Lin; Qu, Junle; Kang, Kang; Gou, Deming

2015-01-01

We herein describe a simple, sensitive and specific method for analysis of circulating microRNAs (miRNA), termed S-Poly(T) Plus real-time PCR assay. This new method is based on our previously developed S-Poly(T) method, in which a unique S-Poly(T) primer is used during reverse-transcription to increase sensitivity and specificity. Further increased sensitivity and simplicity of S-Poly(T) Plus, in comparison with the S-Poly(T) method, were achieved by a single-step, multiple-stage reaction, where RNAs were polyadenylated and reverse-transcribed at the same time. The sensitivity of circulating miRNA detection was further improved by a modified method of total RNA isolation from serum/plasma, S/P miRsol, in which glycogen was used to increase the RNA yield. We validated our methods by quantifying miRNA expression profiles in the sera of the patients with pulmonary arterial hypertension associated with congenital heart disease. In conclusion, we developed a simple, sensitive, and specific method for detecting circulating miRNAs that allows the measurement of 266 miRNAs from 100 μl of serum or plasma. This method presents a promising tool for basic miRNA research and clinical diagnosis of human diseases based on miRNA biomarkers. PMID:26459910

Findings suggest possible link between geomagnetic reversals and field intensity

NASA Astrophysics Data System (ADS)

Hoffman, Kenneth A.

For the past 2000 years the Earth's magnetic field has been weakening. At the going rate of decay, the field's dipole—generated within the convecting metallic fluid of the outer core—would totally vanish, perhaps passing through zero and reversing polarity, in the coming millennia. This scenario of a coming attempt by Earth's dynamo to reverse its polarity is suggested by direct observation of the field since the 19th century and laboratory investigation of historic lavas and other fired materials that record the ambient field while cooling.The ongoing weakening of the field does not insure that a reversal will occur. After all, the north-south axial dipole changes to the opposite direction only on occasion; it currently reverses a few times each million years. How the dynamo actually approaches an attempted change of polarity and, moreover, the degree to which such a process can be predicted, are unclear. Nonetheless, a major step toward such an understanding may have been made through recently reported paleomagnetic findings obtained from the long, quasi-continuous records derived from Ocean Drilling Project (ODP) marine sediment cores.

Mapping the Intricacies of the Gulf of Mexico's Circulation

NASA Astrophysics Data System (ADS)

Lugo-Fernández, Alexis; Green, Rebecca E.

2011-01-01

From hosting key shipping lines, drilling platforms, and commercial fisheries, to sustaining mangrove swamps that shelter the coastline from the hurricanes that churn its waters, the Gulf of Mexico is important to the nations surrounding it for socio-economic, ecological, military, political, and scientific reasons. Critical to all of these sectors is the Gulf's circulation—it controls hurricane tracks and intensity, biological productivity, and larvae dispersal. Since 1982, the Environmental Studies Program (ESP) of the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) has invested more than $67 million in field and numerical modeling studies to improve our understanding of the Gulf's circulation (see Figure 1). ESP-funded research has covered a broad array of topics, some applied and some basic. Studies carried out on behalf of the bureau reflect the bureau's information needs, stakeholder input, and offshore energy exploration and development trends. All ESP studies culminate in a technical report—127 technical reports on physical oceanography are publicly available (see http://www.gomr.boemre.gov/homepg/regulate/environ/techsumm/rec_pubs.html). Additionally, more than 100 peer-reviewed publications have been issued on the Gulf's physical oceanography and circulation. The AGU Geophysical Monograph Circulation in the Gulf of Mexico: Observations and Models, the very first circulation overview since 1972, was funded by ESP. Additionally, data collected during fieldwork are deposited in national archives for public dissemination.

A Babcock-Leighton Solar Dynamo Model with Multi-cellular Meridional Circulation in Advection- and Diffusion-dominated Regimes

NASA Astrophysics Data System (ADS)

Belucz, Bernadett; Dikpati, Mausumi; Forgács-Dajka, Emese

2015-06-01

Babcock-Leighton type-solar dynamo models with single-celled meridional circulation are successful in reproducing many solar cycle features. Recent observations and theoretical models of meridional circulation do not indicate a single-celled flow pattern. We examine the role of complex multi-cellular circulation patterns in a Babcock-Leighton solar dynamo in advection- and diffusion-dominated regimes. We show from simulations that the presence of a weak, second, high-latitude reverse cell speeds up the cycle and slightly enhances the poleward branch in the butterfly diagram, whereas the presence of a second cell in depth reverses the tilt of the butterfly wing to an antisolar type. A butterfly diagram constructed from the middle of convection zone yields a solar-like pattern, but this may be difficult to realize in the Sun because of magnetic buoyancy effects. Each of the above cases behaves similarly in higher and lower magnetic diffusivity regimes. However, our dynamo with a meridional circulation containing four cells in latitude behaves distinctly differently in the two regimes, producing solar-like butterfly diagrams with fast cycles in the higher diffusivity regime, and complex branches in butterfly diagrams in the lower diffusivity regime. We also find that dynamo solutions for a four-celled pattern, two in radius and two in latitude, prefer to quickly relax to quadrupolar parity if the bottom flow speed is strong enough, of similar order of magnitude as the surface flow speed.

A BABCOCK–LEIGHTON SOLAR DYNAMO MODEL WITH MULTI-CELLULAR MERIDIONAL CIRCULATION IN ADVECTION- AND DIFFUSION-DOMINATED REGIMES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belucz, Bernadett; Forgács-Dajka, Emese; Dikpati, Mausumi, E-mail: bbelucz@astro.elte.hu, E-mail: dikpati@ucar.edu

Babcock–Leighton type-solar dynamo models with single-celled meridional circulation are successful in reproducing many solar cycle features. Recent observations and theoretical models of meridional circulation do not indicate a single-celled flow pattern. We examine the role of complex multi-cellular circulation patterns in a Babcock–Leighton solar dynamo in advection- and diffusion-dominated regimes. We show from simulations that the presence of a weak, second, high-latitude reverse cell speeds up the cycle and slightly enhances the poleward branch in the butterfly diagram, whereas the presence of a second cell in depth reverses the tilt of the butterfly wing to an antisolar type. A butterflymore » diagram constructed from the middle of convection zone yields a solar-like pattern, but this may be difficult to realize in the Sun because of magnetic buoyancy effects. Each of the above cases behaves similarly in higher and lower magnetic diffusivity regimes. However, our dynamo with a meridional circulation containing four cells in latitude behaves distinctly differently in the two regimes, producing solar-like butterfly diagrams with fast cycles in the higher diffusivity regime, and complex branches in butterfly diagrams in the lower diffusivity regime. We also find that dynamo solutions for a four-celled pattern, two in radius and two in latitude, prefer to quickly relax to quadrupolar parity if the bottom flow speed is strong enough, of similar order of magnitude as the surface flow speed.« less

Improvement in intra-aortic balloon pumping and evaluation of its efficacy by electrode methods of control.

PubMed

Ioseliani, G D; Chilaia, S M

1983-02-01

A basically new design for the reversing balloon pump has been proposed for increasing the efficacy of intra-aortic balloon pumping (IABP). The device not only causes a significant increase in discharge, but also permits control of the central and peripheral circulation within the desired limits owing to back-and-forth movements (like a piston) of the balloon pump. Standard one- and two-chamber balloon pumps were compared. In addition to traditional hemodynamic and biochemical indexes, the efficacy of IABP was assessed based on electrode monitor control of PO2 and pH in the myocardium, peripheral tissues, and circulating blood. Based on 54 experiments on dogs, it was found that IABP with reversing balloon pumps in synchronous pulsation resulted in survival of 69% of the cases; PO2 and pH levels in the myocardium, tissues, and blood in the coronary sinus were close to normal, and coronary blood flow and peripheral circulation were increased. With standard one-chamber balloon pumps, the survival rate did not exceed 33.4%; PO2 and pH in the peripheral tissues reached critical levels.

High-Resolution Paleomagnetic Observations from Ocean Drilling: Insights from Coring Thick Sediment Drift Deposits

NASA Astrophysics Data System (ADS)

Acton, G. D.; Clement, B. M.; Lund, S. P.; Okada, M.; Williams, T.

2003-04-01

With the advent of the Hydraulic Piston Corer at the end of the Deep Sea Drilling Program and its enhanced successor, the Advanced Piston Corer (APC), developed by the Ocean Drilling Program (ODP), coring through thick (>100 m), rapidly deposited sequences of unconsolidated to partially consolidated sediments with near 100% recovery has become common place. Although much of the emphasis for site selection has been based on paleoceanographic objectives, the impact to the field of paleomagnetism has been dramatic, both in the instruments used to analyze the large quantity of core recovered and in the questions that can be answered concerning geomagnetic field behavior and paleoenvironmental conditions. The largest change has come in the construction of relative paleointensity records, which have provided previously unimagined details about how the geomagnetic field varies in strength during stable polarity intervals as well as during reversals and excursions. These records have allowed more realistic models of the geomagnetic field to be developed while also providing a new chronologic tool for high-resolution dating and global correlation of geomagnetic events. Studies of how the paleomagnetic direction varies through time have not advanced as rapidly and have instead mainly been focused on short time intervals across a few geomagnetic reversals. It should, however, be possible to construct and compare secular variation records with millennial or better resolution that span the past one million years from sites around the world as correlation and chronologies between sites improve. We will give an overview that focuses on secular variation records that are being constructed from sediment drifts drilled in the western North Atlantic during ODP Leg 172. Our results will be used to address questions concerning what percent of time the geomagnetic field is in a stable state versus transitional or excursional states, what the relationship is between directional variability and relative paleointensity, which secular variation features are global and which are local, what is the origin of local directional changes, and how climate and rock magnetic changes influence the paleomagnetic signal.

An Experimental Investigation of the Risk of Triggering Geological Disasters by Injection under Shear Stress

PubMed Central

Liu, Yixin; Xu, Jiang; Peng, Shoujian

2016-01-01

Fluid injection has been applied in many fields, such as hazardous waste deep well injection, forced circulation in geothermal fields, hydraulic fracturing, and CO2 geological storage. However, current research mainly focuses on geological data statistics and the dominating effects of pore pressure. There are only a few laboratory-conditioned studies on the role of drilling boreholes and the effect of injection pressure on the borehole wall. Through experimental phenomenology, this study examines the risk of triggering geological disasters by fluid injection under shear stress. We developed a new direct shear test apparatus, coupled Hydro-Mechanical (HM), to investigate mechanical property variations when an intact rock experienced step drilling borehole, fluid injection, and fluid pressure acting on the borehole and fracture wall. We tested the peak shear stress of sandstone under different experimental conditions, which showed that drilling borehole, water injection, and increased pore pressure led to the decrease in peak shear stress. Furthermore, as pore pressure increased, peak shear stress dispersion increased due to crack propagation irregularity. Because the peak shear stress changed during the fluid injection steps, we suggest that the risk of triggering geological disaster with injection under shear stress, pore, borehole, and fluid pressure should be considered. PMID:27929142

An Experimental Investigation of the Risk of Triggering Geological Disasters by Injection under Shear Stress.

PubMed

Liu, Yixin; Xu, Jiang; Peng, Shoujian

2016-12-08

Fluid injection has been applied in many fields, such as hazardous waste deep well injection, forced circulation in geothermal fields, hydraulic fracturing, and CO 2 geological storage. However, current research mainly focuses on geological data statistics and the dominating effects of pore pressure. There are only a few laboratory-conditioned studies on the role of drilling boreholes and the effect of injection pressure on the borehole wall. Through experimental phenomenology, this study examines the risk of triggering geological disasters by fluid injection under shear stress. We developed a new direct shear test apparatus, coupled Hydro-Mechanical (HM), to investigate mechanical property variations when an intact rock experienced step drilling borehole, fluid injection, and fluid pressure acting on the borehole and fracture wall. We tested the peak shear stress of sandstone under different experimental conditions, which showed that drilling borehole, water injection, and increased pore pressure led to the decrease in peak shear stress. Furthermore, as pore pressure increased, peak shear stress dispersion increased due to crack propagation irregularity. Because the peak shear stress changed during the fluid injection steps, we suggest that the risk of triggering geological disaster with injection under shear stress, pore, borehole, and fluid pressure should be considered.

Preliminary geologic framework developed for a proposed environmental monitoring study of a deep, unconventional Marcellus Shale drill site, Washington County, Pennsylvania

USGS Publications Warehouse

Stamm, Robert G.

2018-06-08

BackgroundIn the fall of 2011, the U.S. Geological Survey (USGS) was afforded an opportunity to participate in an environmental monitoring study of the potential impacts of a deep, unconventional Marcellus Shale hydraulic fracturing site. The drill site of the prospective case study is the “Range Resources MCC Partners L.P. Units 1-5H” location (also referred to as the “RR–MCC” drill site), located in Washington County, southwestern Pennsylvania. Specifically, the USGS was approached to provide a geologic framework that would (1) provide geologic parameters for the proposed area of a localized groundwater circulation model, and (2) provide potential information for the siting of both shallow and deep groundwater monitoring wells located near the drill pad and the deviated drill legs.The lead organization of the prospective case study of the RR–MCC drill site was the Groundwater and Ecosystems Restoration Division (GWERD) of the U.S. Environmental Protection Agency. Aside from the USGS, additional partners/participants were to include the Department of Energy, the Pennsylvania Geological Survey, the Pennsylvania Department of Environmental Protection, and the developer Range Resources LLC. During the initial cooperative phase, GWERD, with input from the participating agencies, drafted a Quality Assurance Project Plan (QAPP) that proposed much of the objectives, tasks, sampling and analytical procedures, and documentation of results.Later in 2012, the proposed cooperative agreement between the aforementioned partners and the associated land owners for a monitoring program at the drill site was not executed. Therefore, the prospective case study of the RR–MCC site was terminated and no installation of groundwater monitoring wells nor the collection of nearby soil, stream sediment, and surface-water samples were made.Prior to the completion of the QAPP and termination of the perspective case study the geologic framework was rapidly conducted and nearly completed. This was done for three principal reasons. First, there was an immediate need to know the distribution of the relatively undisturbed surface to near-surface bedrock geology and unconsolidated materials for the collection of baseline surface data prior to drill site development (drill pad access road, drill pad leveling) and later during monitoring associated with well drilling, well development, and well production. Second, it was necessary to know the bedrock geology to support the siting of: (1) multiple shallow groundwater monitoring wells (possibly as many as four) surrounding and located immediately adjacent to the drill pad, and (2) deep groundwater monitoring wells (possibly two) located at distance from the drill pad with one possibly being sited along one of the deviated production drill legs. Lastly, the framework geology would provide the lateral extent, thickness, lithology, and expected discontinuities of geologic units (to be parsed or grouped as hydrostratigraphic units) and regional structure trends as inputs into the groundwater model.This report provides the methodology of geologic data accumulation and aggregation, and its integration into a geographic information system (GIS) based program. The GIS program will allow multiple data to be exported in various formats (shapefiles [.shp], database files [.dbf], and Keyhole Markup Language files [.KML]) for use in surface and subsurface geologic site characterization, for sampling strategies, and for inputs for groundwater modeling.

Bering Sea Nd isotope records of North Pacific Intermediate Water circulation

NASA Astrophysics Data System (ADS)

Rabbat, C.; Knudson, K. P.; Goldstein, S. L.

2017-12-01

North Pacific Intermediate Water (NPIW) is the primary water mass associated with Pacific meridional overturning circulation. While the relationship between Atlantic meridional overturning circulation and climate has been extensively studied, a lack of suitable sediment cores has limited past investigations of North Pacific climate and NPIW variability. Integrated Ocean Drilling Program Site U1342 (818 m water depth) on Bower's Ridge in the Bering Sea is located at a sensitive depth for detecting changes in NPIW, and it is the only available sub-arctic North Pacific site that offers long, continuous core recovery, relatively high sedimentation rates, excellent foraminifera preservation, and a well-constrained age model over multiple glacial-interglacial cycles. Previous work at Site U1342 from Knudson and Ravelo (2015), using non-quantitative circulation proxies, provides evidence for enhanced NPIW formation during extreme glacials associated with the closure of the Bering Strait and suggest that NPIW was formed locally within the Bering Sea. Our work builds on the potential importance of these results and applies more robust and potentially quantitative circulation proxies to constrain NPIW variability. Here, we present new records of NPIW circulation from Site U1342 based on Nd isotope analyses on fish debris and Fe-Mn encrusted foraminifera, which serve as semi-quantitative "water mass tracers." Weak Bering Sea NPIW formation and ventilation are reflected by relatively lower eNd values indicative of open subarctic North Pacific waters, which are presently predominant, whereas enhanced Bering Sea NPIW formation and ventilation are be reflected by relatively higher eNd values due to the input of Nd from regional volcanic rocks.

Initial results from the Nankai Trough shallow splay and frontal thrust (IODP Expedition 316): Implications for fluid flow

NASA Astrophysics Data System (ADS)

Screaton, E.; Kimura, G.; Curewitz, D.; Scientists, E.

2008-12-01

Integrated Ocean Drilling Program (IODP) Expedition 316 examined the frontal thrust and the shallow portion of the megasplay fault offshore of the Kii peninsula, and was the third drilling expedition of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE). NanTroSEIZE will integrate seafloor observations, drilling, and observatories to investigate the processes controlling slip along subduction zone plate boundary fault systems. Site C0004 examined a shallow portion of the splay fault system where it overrides slope basin sediments. Site C0008, located in the slope basin 1 km seaward of Site C0004, provided a reference site for the footwall sediments. Results of drilling indicate that the footwall sediments have dewatered significantly, suggesting permeable routes for fluid escape. These high-permeability pathways might be provided by coarse-grained layers within the slope sediments. In situ dewatering and multiple fluid escape paths will tend to obscure any geochemical signature of flow from depth. Sites C0006 and C0007 examined the frontal thrust system. Although poorly recovered, coarse-grained trench sediments were sampled within the footwall. These permeable sediments would be expected to allow rapid escape of any fluid pressures due to loading. At both sites, low porosities are observed at shallow depths, suggesting removal of overlying material. This observation is consistent with interpretations that the prism is unstable and currently in a period of collapse. Anomalously low temperatures were measured within boreholes at these sites. One possible explanation for the low temperatures is circulation of seawater along normal faults in the unstable prism.

Higher Circulating Leukocytes in Women with PCOS is Reversed by Aerobic Exercise

PubMed Central

Covington, Jeffrey D.; Tam, Charmaine S.; Pasarica, Magdalena; Redman, Leanne M.

2014-01-01

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance, elevated circulating leukocytes, and hypothesized to have higher adipose tissue inflammation. Aerobic exercise reduces circulating leukocytes and improves insulin sensitivity in obese individuals, but the effect of exercise on inflammation in PCOS is not known. We investigated circulating leukocytes, insulin sensitivity by euglycemic-hyperinsulinemic clamp, serum pro- and anti-inflammatory markers (hsCRP, TNF-α, total and high molecular weight adiponectin), and abdominal subcutaneous adipose tissue (SAT) gene expression of proinflammatory markers in 8 PCOS women and 8 obese control females matched for BMI. Additionally, in a prospective study, the 8 women with PCOS underwent a 16-week aerobic exercise regimen with the same measures performed post-intervention. Compared to controls, white blood cell counts (WBC) were 30% higher (p = 0.04) and circulating total adiponectin levels were 150% lower (p = 0.03) in women with PCOS at baseline/pre-exercise conditions. SAT gene expression of macrophage migration inhibitory factor (MIF, p < 0.01) and interleukin-6 (IL-6, p < 0.05) were also lower in women with PCOS. In response to 16 weeks of aerobic exercise, insulin sensitivity improved (p < 0.01) and WBC counts decreased (p = 0.02). The exercise-induced change in WBC and circulating neutrophils correlated inversely with changes in glucose disposal rate (r= -0.73, p=0.03; and r= -0.82, p=0.01, respectively). Aerobic exercise reduced serum leptin (p < 0.05) after 4 weeks, trended to reduce the ratio of leptin-to-high molecular weight adiponectin (p < 0.1) by the 8th week, and significantly increased serum dehydroepiandrosterone sulfate (DHEA-S, p < 0.001) after 16 weeks. In conclusion, women with PCOS have higher circulating leukocytes compared to controls, which can be reversed by aerobic exercise and is associated with improvements in insulin sensitivity. PMID:25446648

AZD2171, a Pan-VEGF Receptor Tyrosine Kinase Inhibitor, Normalizes Tumor Vasculature and Alleviates Edema in Glioblastoma Patients

PubMed Central

Batchelor, Tracy T.; Sorensen, A. Gregory; di Tomaso, Emmanuelle; Zhang, Wei-Ting; Duda, Dan G.; Cohen, Kenneth S.; Kozak, Kevin R.; Cahill, Daniel P.; Chen, Poe-Jou; Zhu, Mingwang; Ancukiewicz, Marek; Mrugala, Maciej M.; Plotkin, Scott; Drappatz, Jan; Louis, David N.; Ivy, Percy; Scadden, David T.; Benner, Thomas; Loeffler, Jay S.; Wen, Patrick Y.; Jain, Rakesh K.

2009-01-01

SUMMARY Using MRI techniques, we show here that normalization of tumor vessels in recurrent glioblastoma patients by daily administration of AZD2171—an oral tyrosine kinase inhibitor of VEGF receptors—has rapid onset, is prolonged but reversible, and has the significant clinical benefit of alleviating edema. Reversal of normalization began by 28 days, though some features persisted for as long as four months. Basic FGF, SDF1α, and viable circulating endothelial cells (CECs) increased when tumors escaped treatment, and circulating progenitor cells (CPCs) increased when tumors progressed after drug interruption. Our study provides insight into different mechanisms of action of this class of drugs in recurrent glioblastoma patients and suggests that the timing of combination therapy may be critical for optimizing activity against this tumor. PMID:17222792

Charge-reversal nanoparticles: novel targeted drug delivery carriers.

PubMed

Chen, Xinli; Liu, Lisha; Jiang, Chen

2016-07-01

Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosage-controlled approaches. Charge-reversal nanoparticles can release their drug payload in response to specific stimuli that alter the charge on their surface. They can elude clearance from the circulation and be activated by protonation, enzymatic cleavage, or a molecular conformational change. In this review, we discuss the physiological basis for, and recent advances in the design of charge-reversal nanoparticles that are able to control drug biodistribution in response to specific stimuli, endogenous factors (changes in pH, redox gradients, or enzyme concentration) or exogenous factors (light or thermos-stimulation).

3D navigated implantation of the glenoid component in reversed shoulder arthroplasty. Feasibility and results in an anatomic study.

PubMed

Stübig, Timo; Petri, Maximilian; Zeckey, Christian; Hawi, Nael; Krettek, Christian; Citak, Musa; Meller, Rupert

2013-12-01

Reversed shoulder arthroplasty is an alternative to total shoulder arthroplasty for various indications. The long-term results depend on stable bone fixation, and correct positioning of the glenoid component. The potential contribution of image guidance for reversed shoulder arthroplasty procedures was tested in vitro. 27 positioning procedures (15 navigated, 12 non-navigated) of the glenoid baseplate in reverse shoulder arthroplasty were performed by a single experienced orthopaedic surgeon. A Kirschner wire was placed freehand or with the use of a navigated drill guide. For the navigated procedures, a flat detector 3D C-arm with navigation system was used. The Kirschner wire was to be inserted 12 mm from the inferior glenoid, with an inferior tilt of 10° and centrally in the axial scapular axis. The insertion point in the glenoid as well as the position of the K-wire in the axial and sagittal planes were measured. For statistical analysis, t-tests were performed with a significance level of 0.05. The inferior glenoid drilling distance was 14.1 ± 3.4 mm for conventional placement and 15.1 ± 3.4 mm for the navigated procedure (P = 0.19). The inferior tilt showed no significant difference between the two methods (conventional 7.4 ± 5.2°, navigated 7.7 ± 4.9°, P = 0.63). The glenoid version in the axial plane showed significantly higher accuracy for the navigated procedure, with a mean deviation of 1.6 ±4.5° for the navigated procedure compared with 11.5 ± 6.5° for the conventional procedure(P = 0.004). Accurate positioning of the glenoidal baseplate in the axial scapular plane can be improved using 3D C-arm navigation for reversed shoulder arthroplasty. However, computer navigation may not improve the inferior tilt of the component or the position in the inferior glenoid to avoid scapular notching. Nevertheless, further studies are required to confirm these findings in the clinical setup. Copyright © 2013 John Wiley & Sons, Ltd.

Lightweight Magnetic Cooler With a Reversible Circulator

NASA Technical Reports Server (NTRS)

Chen, Weibo; McCormick, John

2011-01-01

A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin GGG disks alternating with thin polymer insulating films. The structured bed reduces flow resistance in the regenerator and therefore the pumping work by the cryogenic circulator. This magnetic cooler will enable cryogenic detectors for sensing infrared, x-ray, gamma-ray, and submillimeter radiation in future science satellites, as well as the detector systems in the Constellation-X (Con-X) and the Single Aperture Far-Infrared observatory (SAFIR). Scientific ap p - lica tions for this innovation include cooling for x-ray micro calorimeter spectrometers used for microanalysis, cryogenic particle detectors, and superconducting tunnel junction de tectors for biomolecule mass spectrometry. The cooler can be scaled to provide very large cooling capacities at very low temperatures, ideal for liquid helium and liquid hydrogen productions.

Structural Analysis of the Pärvie Fault in Northern Scandinavia

NASA Astrophysics Data System (ADS)

Baeckstroem, A.; Rantakokko, N.; Ask, M. V.

2011-12-01

The Pärvie fault is the largest known postglacial fault in the world with a length of about 160 km. The structure has a dominating fault scarp as its western perimeter but in several locations it is rather a system of several faults. The current fault scarps, mainly caused by reverse faulting, are on average, 10-15 m in height and are thought to have been formed during one momentous event near the end of the latest glaciation (the Weichselian, 9,500-115,000 BP ) (Lagerbäck & Sundh, 2008). This information has been learnt from studying deformation features in sediments from the latest glaciation. However, the fault is believed to have been formed as early as the Precambrian, and it has been reactivated repeatedly throughout its history. The earlier history of this fault zone is still largely unknown. Here we present a pre-study to the scientific drilling project "Drilling Active Faults in Northern Europe", that was submitted to the International Continental Scientific Drilling Program (ICDP) in 2009 (Kukkonen et al. 2010) with an ICDP-sponsored workshop in 2010 (Kukkonen et al. 2011). During this workshop a major issue to be addressed before the start of drilling was to reveal whether the fault scarps were formed by one big earthquake or by several small ones (Kukkonen et al. 2011). Initial results from a structural analysis by Riad (1990) have produced information of the latest kinematic event where it is suggested that the latest event coincides with the recent stress field, causing a transpressional effect. The geometrical model suggested for an extensive area of several fault scarps along the structure is the compressive tulip structure. In the southern part, where the fault dips steeply E, the structure is parallel to the foliation of the country rock and earlier breccias, thus indicating a dependence of earlier structures. Modelling of the stress field during the latest glaciation show that a reverse background stress field together with excess pore pressure governs the destabilization of a structure, such as the Pärvie fault, rather than the induced stresses from the weight of ice-sheet (Lund, 2005). This is a presentation of the first part of the structural analysis of the brittle structures around the Pärvie fault in order to evaluate its brittle deformation history and to attempt to constrain the paleostress fields causing these deformations. References Kukkonen, I.T., Olesen, O., Ask, M.V.S., and the PFDP Working Group, 2010. Postglacial faults in Fennoscandia: targets for scientific drilling. GFF, 132:71-81. Kukkonen, I.T., Ask, M.V.S., Olesen, O., 2011. Postglacial Fault Drilling in Northern Europe: Workshop in Skokloster, Sweden. Scientific Drilling, 11, doi:10.2204/iodp.sd.11.08.2011. Lagerbäck, R. & Sundh, M., 2008. Early Holocene faulting and paleoseismicity in northern Sweden. Geological survey of Sweden. Research paper, C 836. 80 p. Lund, B., Schmidt, P., Hieronymus, C., 2009. Stress evolution and fault stability during the Weichselian glacial cycle. Swedish Nuclear Fuel and Waste Management Co., Stockholm. TR-09-15. 106 p. Riad, L., 1990. The Pärvie fault, Northern Sweden, Uppsala University. Research report 63. 48 p

Significance of detecting circulating hepatocellular carcinoma cells in peripheral blood of hepatocellular carcinoma patients by nested reverse transcription-polymerase chain reaction and its clinical value: a retrospective study.

PubMed

Liu, Yang; Wang, Yue-ru; Wang, Long; Song, Rui-mei; Zhou, Bo; Song, Zhen-shun

2014-01-01

Circulating hepatocellular carcinoma cells may be detected by reverse transcription-polymerase chain reaction. We investigated the relationship between circulating hepatocellular carcinoma cells and hepatoma patient survival after different managements and survival periods. Peripheral vein blood (5 ml) samples were obtained from 113 patients with hepatocellular carcinoma and from 33 control subjects (9 with liver cirrhosis after hepatitis B, 14 with chronic hepatitis B, 10 healthy individuals) between January 1, 2009, and December 31, 2013. To detect circulating hepatocellular carcinoma cells in peripheral blood, alpha-fetoprotein messenger RNA was amplified from total RNA extracted from whole blood by reverse transcription-polymerase chain reaction. Alpha-fetoprotein messenger RNA was detected in 59 blood samples from the hepatocellular carcinoma patients (59/113, 52.2%). In contrast, there were no clinical control subjects whose samples showed detectable alpha-fetoprotein messenger RNA. The presence of alpha-fetoprotein messenger RNA in blood seemed to be correlated with the stage (by TNM classification) of hepatocellular carcinoma, serum alpha-fetoprotein value, and the presence of intrahepatic metastasis, portal vein thrombosis, tumor diameter and/or distant metastasis. In addition, alpha-fetoprotein messenger RNA was detected in the blood of 25 patients showing distant metastasis at extrahepatic organs (100%), in contrast to 32 of 88 cases without metastasis (36.4%). All the patients with hepatocellular carcinoma were followed. Seventeen patients with resection of a T 2 stage hepatocellular carcinoma had a survival of 3.2 years after surgical management, 38 cases with resection of a T3 stage hepatocellular carcinoma had a 1.3-year survival, and only 37 cases with T4 stage disease after different treatments except surgery survived for 0.6 years (P <0.01). The presence of alpha-fetoprotein messenger RNA in peripheral blood may be an indicator of circulating hepatocellular carcinoma cells, which might predict hematogenous spreading metastasis in patients with hepatocellular carcinoma and may be a poor prognostic factor for hepatocellular carcinoma patients.

Origin and significance of clay-coated fractures in mudrock fragments of the SAFOD borehole (Parkfield, California)

USGS Publications Warehouse

Schleicher, A.M.; van der Pluijm, B.A.; Solum, J.G.; Warr, L.N.

2006-01-01

The clay mineralogy and texture of rock fragments from the SAFOD borehole at 3067 m and 3436 m measured depth (MD) was investigated by electron microscopy (SEM, TEM) and X-ray-diffraction (XRD). The washed and ultrasonically cleaned samples show slickenfiber striations and thin films of Ca-K bearing smectite that are formed on polished fault surfaces, along freshly opened fractures and within adjacent mineralized veins. The cation composition and hydration behavior of these films differ from the Namontmorillonite of the fresh bentonite drilling mud, although there is more similarity with circulated mud recovered from 3479 m MD. We propose that these thin film smectite precipitates formed by natural nucleation and crystal growth during fault creep, probably associated with the shallow circulation of low temperature aqueous fluids along this shallow portion of the San Andreas Fault. Copyright 2006 by the American Geophysical Union.

Technology Transfer at Edgar Mine: Phase 1; October 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustine, Chad R.; Bauer, Stephen; Nakagawa, Masami

The objective of this project is to study the flow of fluid through the fractures and to characterize the efficiency of heat extraction (heat transfer) from the test rock mass in the Edgar Mine, managed by Colorado School of Mines in Idaho Springs, CO. The experiment consists of drilling into the wall of the mine and fracturing the rock, characterizing the size and nature of the fracture network, circulating fluid through the network, and measuring the efficiency of heat extraction from the 'reservoir' by monitoring the temperature of the 'produced' fluid with time. This is a multi-year project performed asmore » a collaboration between the National Renewable Energy Laboratory, Colorado School of Mines and Sandia National Laboratories and carried out in phases. This report summarizes Phase 1: Selection and characterization of the location for the experiment, and outlines the steps for Phase 2: Circulation Experiments.« less

Geothermal materials development

NASA Astrophysics Data System (ADS)

Kukacka, L. E.

1991-12-01

Advances in the development of new materials, the commercial availabilities of which are essential for the attainment of Hydrothermal Category Level 1 and 2 Objectives, continue to be made in the Geothermal Materials Development Project. Many successes have already been accrued and the results used commercially. In FY-91, utility company sponsored 'full cost' recovery programs based upon materials technology developed in this project were initiated on topics such as condensing heat exchangers, high temperature composites for utility vaults used in district heating systems, and corrosion resistant coatings for use in oil-fired electric generating processes. In FY-91, the DOE/GD-sponsored R&D project was focused on reducing well drilling, fluid transport and energy conversion costs. Specific activities being performed included lightweight CO2-resistant well cements, chemical systems for lost circulation control, thermally conductive and scale resistant protective linear systems, corrosion mitigation in process components at The Geysers, and elastomer-metal bonding systems needed for use in high temperature well drilling and safety related applications.

A ~600 kyr duration Early Pleistocene record from the West Turkana (Kenya) HSPDP drill site: elemental XRF variability to reconstruct climate change in Turkana Boy's backyard

NASA Astrophysics Data System (ADS)

Stockhecke, M.; Beck, C. C.; Brown, E. T.; Cohen, A.; Deino, A. L.; Feibel, C. S.; Sier, M.

2015-12-01

Outcrops in the Kenyan and Ethiopian rift valleys document repeated occurrences of freshwater lakes and wooded landscapes over the past 4 million years at locations that are currently seasonally-dry savanna. Studies of the rich fossil records, in combination with outcropping lacustrine sequences, led to major breakthroughs in our knowledge of driving factors in human evolution. However, study of continuous drill core from ancient lake basins provides a basis for to unravel East African climate dynamics in an unseen fashion. The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project, recovered ~2 km of drill core since 2012. A major project goal is characterization of East African paleoclimate in order to evaluate its impact on hominin evolution. XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the HSPDP records contain complex lithologies reflecting repeated episodes of inundation and desiccation of the lake basins. Nevertheless, careful data evaluation based on detailed lithostratigraphy, which includes smear-slide microscopic analyses and X-radiographic images, allows disentanglement of complex signals and robust identification of continuous sequences for any cyclostratigraphic and statistical analysis. At the HSPDP Turkana Basin site a 175.6 m-long core the covers the Early Pleistocene time window during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. This drill site carries particular interest as it is located in only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Turkana Boy). Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive and environmentally meaningful paleoclimate timeseries. In addition, the XRF record of the changing hydroclimate of the West Turkana Basin from 1.3 to 1.9 kyrs will be explored in relation to regional reconstructions and marine stratigraphies.

Mississippi River: Study of Alternatives for Rehabilitation of Lock and Dam Number 1. Minneapolis, Minnesota. Volume 3. Appendices B-F.

DTIC Science & Technology

1976-04-01

AR2 RECIPIENT’S CATALOG NUMBER A. TiTLE CadSubtitIe) MISSISSIPPI RIVER STUDY OF TYPE OF REPORT & PERIOD COVERED ALTERNATIVES FOR REHABILITATION OF LOCK...USPO & Custom House St. Paul, MN 55101 1. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE April, 1976 13. NUMBER OF PAGES 283 p. 14. MONITORING...Borehole 74-9 19 5 Sumary of Circulation History of Borehole. in Which Partial or Total Loss of Drilling was Recorded 20 FIGURES Number Description pg 1

Hawaii Scientific Drilling Project: Objectives, Successes, Surprises and Frustrations

NASA Astrophysics Data System (ADS)

Depaolo, D. J.; Stolper, E.; Thomas, D. M.

2008-12-01

The Hawaii Scientific Drilling Project (HSDP) is a long-running project undertaken with the objective of studying a mantle plume by drilling an extended sequence of lavas from a single Hawaiian volcano. The project originated with a proposal to NSF in late 1986 with the idea of drilling to the Moho under Hilo; the target depth was estimated at 12km, commensurate with the depth reached by the drilling program then being pursued by the USSR and that proposed in the U.S. for the southern Appalachians, and in line with the aspirations of the nascent DOSECC program. Subsequently, due to limitations in funding and reorganization of the drilling program into what later became the NSF Continental Dynamics Program, HSDP was re-scoped with the objective of drilling deeply enough (ca. 4.5km) to recover most of the eruptive history of a single volcano. The project first went to a pilot stage, which resulted in coring to a depth of 1.1km in late 1993. The pilot stage was relatively inexpensive (1M including science) and productive. Funding was then obtained from NSF and ICDP in 1995 (ca. 12M) with the objective of drilling to 4.5km. Drilling was originally planned for a five-year period, in two campaigns. The first campaign, in 1999, resulted in efficient coring to a depth of 3.1km over a period of 6 months; it used about 40 percent of the funds and was also highly productive. Deepening the hole below 3.1km turned out to be both difficult and expensive, although for interesting reasons. To facilitate deeper drilling the hole needed to be reamed to a larger diameter; but when this was done the well unexpectedly started to flow. We now know that there are several deep pressurized aquifers, with varying salt content, but these hydrological phenomena were totally unanticipated. A key finding, also unanticipated, is that cold seawater circulates through the volcanic pile in volumes sufficient to refrigerate the entire section below 700m depth to temperatures about 25 degrees below a normal geothermal gradient. In early 1999 when the first drilling campaign was organized, the price of oil was 10 USD (rigs and drilling crews were available and reasonably priced); in early 2003 when hole opening was being arranged, the price of oil was 30 USD, and for the coring campaigns in 2005 and 2007 it was 50 to 70 USD. For these reasons, and because trip times were longer and deeply buried pillow basalts more difficult to drill, the remainder of the project funds (and then some) were needed to deepen the hole from 3.1 to 3.5km. Nevertheless, the project obtained a nearly continuous, and virtually unweathered, core consisting of lava flows, hyaloclastite, minor intrusives and sediment from a 3260m section of the Mauna Kea volcano, covering an age range from 200 to over 600 ka. It also recovered a 250m and a 280m section of the Mauna Loa volcano. A wealth of geological, volcanological, petrological, geochemical, geomagnetic, geodynamic, hydrological, and geobiological data have come from the core and the well, and more are coming in. The unprecedented geochemical-petrological data sets are a major success, as is the fact that geochemists can work together, but the hoped-for detailed geochronology for the core has proven difficult to obtain.

An Active Broad Area Cooling Model of a Cryogenic Propellant Tank with a Single Stage Reverse Turbo-Brayton Cycle Cryocooler

NASA Technical Reports Server (NTRS)

Guzik, Monica C.; Tomsik, Thomas M.

2011-01-01

As focus shifts towards long-duration space exploration missions, an increased interest in active thermal control of cryogenic propellants to achieve zero boil-off of cryogens has emerged. An active thermal control concept of considerable merit is the integration of a broad area cooling system for a cryogenic propellant tank with a combined cryocooler and circulator system that can be used to reduce or even eliminate liquid cryogen boil-off. One prospective cryocooler and circulator combination is the reverse turbo-Brayton cycle cryocooler. This system is unique in that it has the ability to both cool and circulate the coolant gas efficiently in the same loop as the broad area cooling lines, allowing for a single cooling gas loop, with the primary heat rejection occurring by way of a radiator and/or aftercooler. Currently few modeling tools exist that can size and characterize an integrated reverse turbo-Brayton cycle cryocooler in combination with a broad area cooling design. This paper addresses efforts to create such a tool to assist in gaining a broader understanding of these systems, and investigate their performance in potential space missions. The model uses conventional engineering and thermodynamic relationships to predict the preliminary design parameters, including input power requirements, pressure drops, flow rate, cycle performance, cooling lift, broad area cooler line sizing, and component operating temperatures and pressures given the cooling load operating temperature, heat rejection temperature, compressor inlet pressure, compressor rotational speed, and cryogenic tank geometry. In addition, the model allows for the preliminary design analysis of the broad area cooling tubing, to determine the effect of tube sizing on the reverse turbo-Brayton cycle system performance. At the time this paper was written, the model was verified to match existing theoretical documentation within a reasonable margin. While further experimental data is needed for full validation, this tool has already made significant steps towards giving a clearer understanding of the performance of a reverse turbo-Brayton cycle cryocooler integrated with broad area cooling technology for zero boil-off active thermal control.

The dynamo dilemma

NASA Technical Reports Server (NTRS)

Parker, E. N.

1987-01-01

The recent determination that the angular velocity Omega of the sun declines downward through the convective zone raises serious questions about the nature of the solar dynamo. The principal qualitative features of the sun are the azimuthal fields that migrate toward the equator in association with an oscillating poloidal field which reverses at about the time of maximum appearance of bipolar magnetic regions. If Omega decreases downward, or is negligible, the horizontal gradient in Omega produces a dynamo with some of these essential characteristics. There is reason to think that the dynamo is confined to the lower half of the convective zone, where alpha has the opposite sign from the usual (alpha of greater than 0 in the northern hemisphere) producing equatorward migration but reversing the sign of the associated poloidal field. Meridional circulation may play an essential role in shaping the dynamo. At the present time it is essential to measure Omega accurately and determine the nature of the meridional circulation.

A generalised model of secondary circulation for a wide range of geophysical flows from direct observations of natural turbidity currents

NASA Astrophysics Data System (ADS)

Azpiroz, M.; Cartigny, M.; Sumner, E. J.; Talling, P.; Parsons, D. R.; Clare, M. A.; Cooper, C.

2017-12-01

Turbidity currents transport sediment through submarine channel systems for hundreds of kilometres to form vast deposits of sediment in the deep sea called submarine fans. The largest submarine fans are fed by meandering channels suggesting that bends may enhance sediment transport distances. The interaction between meander bends and turbidity currents has been a topic of intense debate. Due to the absence of observations of deep-sea turbidity currents flowing through meander bends, our understanding has been based on experimental and numerical models. Measurements of geophysical flows demonstrate a common helical flow structure around meanders. Previous work has demonstrated that helical circulation in rivers is dominated by a single helix that rotates towards the inner bend at near-bed depths. In contrast, initial numerical and experimental models for turbidity currents found both river-like and river-reversed circulations. Saline flows in well-mixed estuaries show a river-like basal helical circulation, while stratified estuaries and saline flows are river-reversed. The existence of lateral stratification in stratified flows is thought to be the key factor in the change of direction of rotation. Stratification causes lateral pressure gradients that can govern the rotation of the flow helix. Turbidity currents are stratified due to their upwards-decreasing sediment load. It has therefore been proposed that stratified turbidity currents behave like stratified saline flow, but this hypothesis remains so far untested. Here we present the first observations of the helical flow in turbidity currents, which occurred within the deep-sea Congo Canyon. The measurements show a consistent river-reversed pattern downstream of the bend apex. Those results lead us to develop a new generalised model for a wide range of flows around meanders. Our conclusions have implications for understanding the flow erosional and depositional patterns, the evolution of channel systems and the architecture of the depositional record.

System and method for damping vibration in a drill string using a magnetorheological damper

DOEpatents

Wassell, Mark Ellsworth; Burgess, Daniel E.; Barbely, Jason R.; Thompson, Fred Lamar

2018-05-22

A system for damping vibration in a drill string can include a magnetorheological fluid valve assembly having a supply of a magnetorheological fluid. A remanent magnetic field is induced in the valve during operation that can be used to provide the magnetic field for operating the valve so as to eliminate the need to energize the coils except temporarily when changing the amount of damping required. The current to be supplied to the coil for inducing a desired magnetic field in the valve is determined based on the limiting hysteresis curve of the valve and the history of the magnetization of the value using a binary search methodology. The history of the magnetization of the valve is expressed as a series of sets of current and it resulting magnetization at which the current experienced a reversal compared to prior values of the current.

Thermospheric dynamics during November 21-22, 1981 - Dynamics Explorer measurements and thermospheric general circulation model predictions

NASA Technical Reports Server (NTRS)

Roble, R. G.; Killeen, T. L.; Spencer, N. W.; Heelis, R. A.; Reiff, P. H.

1988-01-01

Time-dependent aurora and magnetospheric convection parameterizations have been derived from solar wind and aurora particle data for November 21-22, 1981, and are used to drive the auroral and magnetospheric convection models that are embedded in the National Center for Atmospheric Research thermospheric general circulation model (TGCM). Neutral wind speeds and transition boundaries between the midlatitude solar-driven circulation and the high-latitude magnetospheric convection-driven circulation are examined on an orbit-by-orbit basis. The results show that TGCM-calculated winds and reversal boundary locations are in generally good agreement with Dynamics Explorer 2 measurements for the orbits studied. This suggests that, at least for this particular period of relatively moderate geomagnetic activity, the TGCM parameterizations on the eveningside of the auroral oval and polar cap are adequate.

pH-Sensitive Reversible Programmed Targeting Strategy by the Self-Assembly/Disassembly of Gold Nanoparticles.

PubMed

Ma, Jinlong; Hu, Zhenpeng; Wang, Wei; Wang, Xinyu; Wu, Qiang; Yuan, Zhi

2017-05-24

A reversible programmed targeting strategy could achieve high tumor accumulation due to its long blood circulation time and high cellular internalization. Here, targeting ligand-modified poly(ethylene glycol) (PEG-ligand), dibutylamines (Bu), and pyrrolidinamines (Py) were introduced on the surface of gold nanoparticles (Au NPs) for reversible shielding/deshielding of the targeting ligands by pH-responsive self-assembly. Hydrophobic interaction and steric repulsion are the main driving forces for the self-assembly/disassembly of Au NPs. The precise self-assembly (pH ≥ 7.2) and disassembly (pH ≤ 6.8) of Au NPs with different ligands could be achieved by fine-tuning the modifying molar ratio of Bu and Py (R m ), which followed the formula R m = 1/(-0.0013X 2 + 0.0323X + 1), in which X is the logarithm of the partition coefficient of the targeting ligand. The assembled/disassembled behavior of Au NPs at pH 7.2 and 6.8 was confirmed by transmission electron microscopy and dynamic light scattering. Enzyme-linked immunosorbent assays and cellular uptake studies showed that the ligands could be buried inside the assembly and exposed when disassembled. More importantly, this process was reversible, which provides the possibility of prolonging blood circulation by shielding ligands associated with the NPs that were effused from tumor tissue.

Bill Lowrie In The Apennines U Reading - The Pelagic Record of Geomagnetic Reversals

NASA Astrophysics Data System (ADS)

Alvarez, Walter

Twenty five years ago, Bill Lowrie and I, along with Mike Arthur, Al Fischer, Gio- vanni Napoleone, Isabella Premoli Silva and Bill Roggenthen, published a set of five papers in the Geological Society of America Bulletin (March 1977), reporting a re- markable new source of information on the geomagnetic polarity time scale. The re- versal sequence was already known back to the Late Cretaceous on the basis of marine magnetic anomalies, but only as a sequence of longer and shorter polarity intervals, a kind of fingerprint with almost no age calibration. At Gubbio, in the Umbrian Apen- nines of Italy, we discovered that the polarity intervals are also recorded in pelagic limestones, deposited quietly at moderate oceanic depths at rates of order 10 m/Myr. and these limestones are literally made of fossils, notably the planktic foraminifera which are the best age correlation tool for the last 100 Myr. The reversal sequence was now datable. You can make a discovery like this either by looking for it, as Al Fischer did U hoping ° that such a record would be present and waiting until magnetometers improved enough to make it possible to measure these very weakly magnetic rocks U or by stumbling ° on it as Bill and I did. We went to the Apennines hoping to measure paleomagnetically a tectonic rotation of the Italian crust. Digital spinner magnetometers had just become available and Bill found that he could measure the remanence of the Apennine pelagic limestones I had been studying in the field. Tectonic rotation of the Italian crust turned out to be very difficult to detect, because interbed slip was a major complication. But we accidentally sampled both normal and reversed beds in the Scaglia rossa limestone on our first trip, and back in the lab we recognized that we had a polarity record in front of us. The microfossils made it a datable record, which raised great excitement among our colleagues at Lamont, where sea-floor magnetic reversals were the key to tectonic reconstructions. We dropped everything else and raced to measure the polar- ity stratigraphy of the Apennine limestones. When we found that Al Fischer and his friends were doing the same, we teamed up with them. Scientifically it was a wonderful project. The pelagic limestone sequence in the Apen- nines represents more than 100 Myr of Earth history, and we worked our way up and down that section over a number of years, publishing papers in which we gradually 1 dated the reversal sequence from the Oligocene back to the end of the Cretaceous Long Normal polarity interval. We had a little window of opportunity because deep- sea drilling cores of similar lithologies on the modern sea floor did not give usable results until the development of the hydraulic piston corer got past the problem of drilling vibrations resetting the magnetization in the soft deep-sea sediments. In con- trast, our hard limestones in the mountains gave excellent results, but only because of the exquisite care Bill took in measuring and cleaning these very weakly magnetic rocks. We felt slightly smug that with a dilapidated Fiat 850 and a converted-chainsaw drill we could get better results than scientists with a multi-million-dollar drilling ship. Even now I cannot hear a chain saw without a flood of memories of the agony of start- ing the thing, and the interesting Scottish words Bill used on occasions like that. In the field we developed high-precision stratigraphic measurement techniques, and returned year after year to fill in the gaps and find the exact position of reversals. It was a great personal and cultural experience as well. Bill and I drove and walked and measured and drilled all over Umbria and the Marche, a land of history, music, gentle beauty, and delicious food. In the evenings we walked in little historic cities like Assisi, Perugia, Spoleto and Gubbio, talking and arguing about history, science, and Mediaeval architecture. In those years Bill undertook my education in geophysics, which has benefitted me ever since. Perhaps it was an omen U on our first trip U when Bill and I stood by a balustrade in ° ° Assisi, looking down to the valley below. The Porziuncola U the basilica built over a ° ruined church that Saint Francis had restored U was precisely transfixed by a perfect ° rainbow. It was almost as if San Francesco were saying, "Welcome to Umbria! Here you will find wonderful things." and that is the way it turned out. 2

Iron Chelation Nanoparticles with Delayed Saturation as an Effective Therapy for Parkinson Disease.

PubMed

Wang, Nan; Jin, Xin; Guo, Dongbo; Tong, Gangsheng; Zhu, Xinyuan

2017-02-13

Iron accumulation in substantia nigra pars compacta (SNpc) has been proved to be a prominent pathophysiological feature of Parkinson's diseases (PD), which can induce the death of dopaminergic (DA) neurons, up-regulation of reactive oxygen species (ROS), and further loss of motor control. In recent years, iron chelation therapy has been demonstrated to be an effective treatment for PD, which has shown significant improvements in clinical trials. However, the current iron chelators are suboptimal due to their short circulation time, side effects, and lack of proper protection from chelation with ions in blood circulation. In this work, we designed and constructed iron chelation therapeutic nanoparticles protected by a zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) to delay the saturation of iron chelators in blood circulation and prolong the in vivo lifetime, with HIV-1 trans-activating transcriptor (TAT) served as a shuttle to enhance the blood-brain barrier (BBB) permeability. We explored and investigated whether the Parkinsonian neurodegeneration and the corresponding symptoms in behaviors and physiologies could be prevented or reversed both in vitro and in vivo. The results demonstrated that iron chelator loaded therapeutic nanoparticles could reverse functional deficits in Parkinsonian mice not only physiologically but also behaviorally. On the contrary, both untreated PD mice and non-TAT anchored nanoparticle treated PD mice showed similar loss in DA neurons and difficulties in behaviors. Therefore, with protection of zwitterionic polymer and prolonged in vivo lifetime, iron chelator loaded nanoparticles with delayed saturation provide a PD phenotype reversion therapy and significantly improve the living quality of the Parkinsonian mice.

Play-fairway analysis for geothermal exploration: Examples from the Great Basin, western USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siler, Drew L; Faulds, James E

2013-10-27

Elevated permeability within fault systems provides pathways for circulation of geothermal fluids. Future geothermal development depends on precise and accurate location of such fluid flow pathways in order to both accurately assess geothermal resource potential and increase drilling success rates. The collocation of geologic characteristics that promote permeability in a given geothermal system define the geothermal ‘fairway’, the location(s) where upflow zones are probable and where exploration efforts including drilling should be focused. We define the geothermal fairway as the collocation of 1) fault zones that are ideally oriented for slip or dilation under ambient stress conditions, 2) areas withmore » a high spatial density of fault intersections, and 3) lithologies capable of supporting dense interconnected fracture networks. Areas in which these characteristics are concomitant with both elevated temperature and fluids are probable upflow zones where economic-scale, sustainable temperatures and flow rates are most likely to occur. Employing a variety of surface and subsurface data sets, we test this ‘play-fairway’ exploration methodology on two Great Basin geothermal systems, the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These analyses, based on 3D structural and stratigraphic framework models, reveal subsurface characteristics about each system, well beyond the scope of standard exploration methods. At Brady’s, the geothermal fairways we define correlate well with successful production wells and pinpoint several drilling targets for maintaining or expanding production in the field. In addition, hot-dry wells within the Brady’s geothermal field lie outside our defined geothermal fairways. At Astor Pass, our play-fairway analysis provides for a data-based conceptual model of fluid flow within the geothermal system and indicates several targets for exploration drilling.« less

Bedrock Geology of the DFDP-2 Drill-Site

NASA Astrophysics Data System (ADS)

Toy, V.; Sutherland, R.; Townend, J.

2015-12-01

Bedrock was encountered in DFDP-2B at drilled depths (MD) of 238.50-893.18 m (vertical depths of 238.40-818.00 m). Continuous sampling of cuttings revealed the bedrock is composed predominantly of ductilely sheared mylonite-series lithologies exhumed from the roots of the Alpine Fault zone. The protolith is interpreted to be amphibolite facies metasediments classified as part of the Aspiring Subdivision of the Torlesse Supergroup. Onsite description of whole cuttings and thin sections made within a few hours of sample recovery allowed identification of progressive structural changes. Fabrics were schistose in the upper part of the hole, but at greater depths we observed increasing indications that the rocks had been subjected to simple shear deformation. These macro-and micro-structural features are consistent with those that typify the Alpine Fault mylonite sequence previously described, and were used as input to drilling decisions. The structural features found to be the most useful indicators of ductile simple shear strain accommodated by the recovered rocks were the occurrence of shear bands; changes in mean quartz grain size; changes in maximum mica grain size; and redistribution of or changes in microstructural setting of accessory phases (e.g. graphite). The quartz:mica ratio based on mass was also determined but the extent to which this reflects true lithologic variations is unclear, as washing and winnowing of the samples (both by circulating drill fluids and during the sample collection process) probably modified bulk mineralogy in different particle size domains. Nevertheless, the quartz:mica dataset suggests a dramatic change in mineralogy at 730 m MD (vertical depth of 695 m). This coincides with a pronounced step in the temperature gradient, possibly related to large changes in hydrogeology.

Mini-CORK observatories using the MeBo seafloor drill rig - a new development for long-term data acquisition and sampling in shallow boreholes

NASA Astrophysics Data System (ADS)

Kopf, A.; Freudenthal, T.; Ratmeyer, V.; Bergenthal, M.; Renken, J.; Zabel, M.; Wefer, G.

2011-12-01

State of the art technology for long-term monitoring of fluid migration within the sea floor is the sealing of a borehole with a Circulation Obviation Retrofit Kit (CORK) after sensor installation and/or fluid sampling devices within the drill string. However, the combined used of a drilling vessels and a remotely operated drilling (ROV) required for a CORK installation in the deep sea is a costly exercise that limits the number of monitoring stations installed. Robotic sea floor drill rigs are a cost effective alternative for shallow drillings down to 50-100 m below sea floor. Here we present a Mini-CORK system that is developed for installation with the sea floor drill rig MeBo. This rig was developed at MARUM Research Centre, University of Bremen in 2005 and can sample the sea floor in water depths up to 2000 m. The MeBo is deployed on the seabed and remotely controlled from the vessel. All required drill tools for wire-line core drilling down to 70 m below sea floor are stored on two rotating magazines and can be loaded below the top drive drill head for assembling the drill string. For one of the upcoming cruises with RV Sonne offshore Japan (Nankai Trough accretionary prism), MeBo will be used for the first time to place observatories. Two different designs have been developed. The first, relatively simple long-term device resembles a MeBo drill rod in its geometry, and contains a pressure and temperature transducer in the borehole plus an identical pair of transducers for seafloor reference. The device also contains a data logger, battery unit, and an acoustic modem so that data can be downloaded at any time from a ship of opportunity. The key element at the base of the observatory rod is a seal at the conical thread to separate the borehole hydraulically from the overlying water body. It is realized by an adapter, which also contains a hotstab hydraulic connection and an electrical connection. The second observatory device is a seafloor unit, which replaces part of the first unit and which is deployed by ROV. In essence, the upper portion of the former observatory is taken away by ROV, and an umbilical containing hydraulic lines and tubing to withdraw formation water from the borehole is plugged into the hotstab female adapter by ROV. At the far end, the umbilical is connected to a seafloor unit with battery power, data logger, P and T transducers, and the same acoustic modem as the former one. In addition, the latter contains osmo samplers and biological chambers (FLOCS) for in situ sampling and experiments. After the envisaged deployment period, the entire unit is replaced while an identical one is prepared on deck and lowered from the vessel. In theory, the MeBo hole infinitely serves as an access to depth since no electronic, but only tubing is lowered into the (open) hole. In summary, long-term borehole installations with MeBo offer an affordable way to measure key physical properties over time and sample the formation fluids for geochemistry and microbiology (in case of the second, ROV-deployed CORK).

Linking downhole logging data with geology and drilling /coring operations - Example from Chicxulub Expedition 364.

NASA Astrophysics Data System (ADS)

Lofi, Johanna; Smith, Dave; Delahunty, Chris; Le Ber, Erwan; Mellet, Claire; Brun, Laurent; Henry, Gilles; Paris, Jehanne

2017-04-01

Expedition 364 was a joint IODP/ICDP mission specific platform expedition to explore the Chicxulub impact crater buried below the Yucatán continental shelf. In April and May 2016, our Expedition drilled a single borehole at Site M0077A into the crater's peak ring. It allowed recovering 303 excellent quality cores from 505.7 to 1334.7 meters below sea floor and acquiring more than 5.8 km of high resolution open hole logs. Downhole logs are rapidly collected, continuous with depth, and measured in situ; these data are classically interpreted in terms of stratigraphy, lithology, porosity, fluid content, geochemical composition and structure of the formation drilled. Downhole logs also allow assessing borehole quality (eg. shape and trajectory), and can provide assistance for decision support during drilling operations. In this work, Expedition 364 downhole logs are used to improve our understanding of the drilling/coring operation history. Differentiating between natural geological features and borehole artifacts are also critical for data quality assessment. The set of downhole geophysical tools used during Expedition 364 was constrained by the scientific objectives, drilling/coring technique, hole conditions and temperature at the drill site. Wireline logging data were acquired with slimline tools in three logging phases at intervals 0-503, 506-699 and 700-1334 mbsf. Logs were recorded either with standalone logging tools or, for the first time in IODP, with stackable slimline tools. Log data included total gamma radiation, sonic velocity, acoustic and optical borehole images, resistivity, conductivity, magnetic susceptibility, caliper and borehole fluid parameters. The majority of measurements were performed in open borehole conditions. During the drilling operations some problems were encountered directly linked to the geology of the drilled formation. For example, two zones of mud circulation losses correlate in depth with the presence of karst cavities or open faults, as evidenced from borehole wall images. Both form conduits probably open at a large scale as suggested by associated anomalies in the borehole fluid temperature profiles. When coring the basement, pieces of metal trapped outside the drill bit apparently led to an increase of the borehole tilt as well as to an enlargement of the hole, although this later remained sub-circular. In the post impact carbonates, 6-7 m long apparent cyclic oscillations in the magnetic field coupled to a spiral shape trajectory of the same wavelength suggest drilling induced artifacts and formation re-magnetization. Acknowledgements: Expedition 364 was funded by IODP with co-funding from ICDP and implemented by ECORD, with contributions and logistical support from the Yucatán state government and Universidad Nacional Autónoma de México. Drilling Services were provided by DOSECC Exploration Services. The downhole logging program was coordinated by EPC, as part of ESO. Expedition 364 Scientists: S. Gulick, J.V. Morgan, E. Chenot, G. Christeson, P. Claeys, C. Cockell, M.J. L. Coolen, L. Ferrière, C. Gebhardt, K. Goto, H. Jones, D.A. Kring, J. Lofi, X. Long, C. Lowery, C. Mellett, R. Ocampo-Torres, L. Perez-Cruz, A. Pickersgill, M. Poelchau, A. Rae, C. Rasmussen, M. Rebolledo-Vieyra, U. Riller, H. Sato, J. Smit, S. Tikoo, N. Tomioka, M. Whalen, A. Wittmann, J. Urrutia-Fucugauchi, K.E. Yamaguchi, W. Zylberman.

Seasonal and Interannual Variability of Eddy Field and Surface Circulation in the Gulf of Aden

NASA Astrophysics Data System (ADS)

Al Saafani, M. A.; Shenoi, S. S. C.

2006-07-01

The circulation in the Gulf of Aden is inferred from three different data sets: h istorical sh ip drifts , hydrography , and satellite altimeter derived sea level (Topex/Poseidon, Jason and ERS) . The circulation in th is semi-enclosed basin is marked with strong seasonality with reversals in the direction of flows twice a year follow ing the reversal in mon soonal winds. During the win ter mon soon (November - February) there is an inflow from Arabian Sea; an extension of Arabian Coastal Current (ACC) . During sou thwest mon soon (June - August) the flow is generally towards east especially along the northern coast of Gulf of Aden. The geostrophic currents also show that the circulation in the gulf is embedded with mesoscale eddies. These westward propagating eddies appear to enter the Gulf of Aden from the western Arabian Sea in win ter. The relative contribu tion of mesoscale eddies to the circulation in the gulf were estimated using altimeter derived Sea level anomaly (SLA) for the years 1993 to 2003 . The effect of these mesoscale eddies extend over the entire water colu mn . The propagation speeds, of these eddies, estimated using weekly spaced altimeter derived SLA (2002 - 2003) is ~ 4 .0 - 5 .3 cm s . The sum of the speeds of second mode Ro ssby wave and the mean current (4.8 cm s ) matches with the propagation speeds of eddies estimated using SLA . Hence, second mode baroclin ic Rossby waves appear to be responsib le for the westward propagation of eddies in the Gulf of Aden. The presence of these eddies in the temperaturesalin ity climato logy confirms that they are no t transient features.

The adaptation of the cerebral circulation to pregnancy: mechanisms and consequences

PubMed Central

Cipolla, Marilyn J

2013-01-01

The adaptation of the cerebral circulation to pregnancy is unique from other vascular beds. Most notably, the growth and vasodilatory response to high levels of circulating growth factors and cytokines that promote substantial hemodynamic changes in other vascular beds is limited in the cerebral circulation. This is accomplished through several mechanisms, including downregulation of key receptors and transcription factors, and production of circulating factors that counteract the vasodilatory effects of vascular endothelial growth factor (VEGF) and placental growth factor. Pregnancy both prevents and reverses hypertensive inward remodeling of cerebral arteries, possibly through downregulation of the angiotensin type 1 receptor. The blood–brain barrier (BBB) importantly adapts to pregnancy by preventing the passage of seizure provoking serum into the brain and limiting the permeability effects of VEGF that is more highly expressed in cerebral vasculature during pregnancy. While the adaptation of the cerebral circulation to pregnancy provides for relatively normal cerebral blood flow and BBB properties in the face of substantial cardiovascular changes and high levels of circulating factors, under pathologic conditions, these adaptations appear to promote greater brain injury, including edema formation during acute hypertension, and greater sensitivity to bacterial endotoxin. PMID:23321787

Radiometric Ages From ODP Leg 197 Drilling Along the Emperor Seamount Chain

NASA Astrophysics Data System (ADS)

Duncan, R. A.; Huard, J.

2002-12-01

The Hawaiian-Emperor Seamount chain is the "type" example of an age-progressive, hotspot-generated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based on radiometric ages determined several decades ago. Improvements in instrumentation, sample preparation methods and new material obtained by recent drilling warrant a re-examination of the age relations among the older Hawaiian volcanoes. We report new age determinations (40Ar-39Ar incremental heating method) on whole rocks and feldspar separates from Detroit (Sites 1203 and 1204), Nintoku (Site 1205) and Koko (Site 1206) seamounts in the Emperor chain, recovered by drilling during ODP Leg 197. Only normal magnetic polarity was observed at Sites 1203 and 1204, and biostratigraphic data assigned ages of 75-76 Ma (nanofossil zone cc22) to sediments interbedded with lava flows. Plateaus in incremental heating age spectra give a mean age for Site 1203 of 75.3 +/- 1.0 Ma (relative to biotite monitor FCT-3 at 28.04 Ma; all errors are 2s). Site 1204 lavas have produced only discordant data so far (5 samples). These new ages are significantly younger than the 81 Ma age reported by Keller et al. (1995) for Site 884 (reverse polarity lavas) on the northeastern flank of Detroit seamount, and suggest that this complex may include several large volcanoes. All volcanic units at Site 1205 exhibit reverse polarity magnetization and biostratigraphic data place the lowermost sediments close to the Eocene-Paleocene boundary. Six plateau ages from lava flows spanning the 283m cored section give a mean age of 55.6 +/- 0.2 Ma (range: 55.2-56.4 Ma), corresponding to Chron 24r. Drilling at Site 1206 intersected a 278m N-R-N sequence of lava flows. Six plateau ages give a mean age of 49.1 +/- 0.2 Ma (range: 47.9-49.7 Ma), corresponding to the Chron 21n-21r-22n sequence. Deep penetration at the three seamounts and shipboard geochemical data suggest that the main shield-post shield stages of volcano development have been sampled at each location and dated. While the overall trend is decreasing volcano age from N to S along the Emperor Seamounts, there appear to be important departures from the earlier modeled simple linear age progression.

Prospecting for Natural Gas Gydrate in the Orca & Choctaw Basins in the Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Cook, A.; Hillman, J. I. T.; Sawyer, D.; Frye, M.; Palmes, S.; Shedd, W. W.

2016-12-01

The Orca and Choctaw salt bounded mini-basins, which occur in 1.5 to 2.5 km water depth on the northern Gulf of Mexico slope, are currently under consideration as an IODP scientific drilling location for coarse-grained natural gas hydrate systems. We use a 3D seismic dataset for gas hydrate prospecting that covers parts of eleven lease blocks ( 200 km2) in the Walker Ridge protraction area. The study area includes the southern section of the Orca Basin and a smaller section of the northern Choctaw Basin. We have mapped a discontinuous bottom-simulating reflection (BSR) over nearly 30% of our seismic dataset, which varies significantly in both amplitude and depth throughout the area. The southeastern section of our dataset contains three positive impedance amplitude horizons with possible phase reversals at the BSR. Detailed mapping in the area also reveals at the base of gas hydrate stability, a complicated intercalation of an east-west trending fault system and an amalgamated deepwater depositional system comprising channel levee deposits and turbidite sheet sands. Three industry wells drilled in the southwestern section of our study area indicate that the sedimentary sequence infilling the basins consists of predominantly mud rich units with interbedded turbidite sands, forming a 2 km thick supra-salt sequence of late Miocene to Pleistocene sediments. Two of the industry wells have strong evidence for natural gas hydrate in clay-rich sediment, with moderate resistivity (between 2-10 Ωm) increases above background resistivity in zones that exceed 60 m thick. Additionally, the electromagnetic resistivity curves in these wells separate suggesting that the gas hydrate occurs in high-angle fractures. We will present our seismic dataset, our continuing analysis and selected drill sites in the Orca and Choctaw basins. Furthermore, our analysis in the southeastern section of the study area underscores the importance of interpreting faults when considering phase reversals in hydrate systems.

Maintenance of Summer Monsoon Circulations: A Planetary-Scale Perspective.

NASA Astrophysics Data System (ADS)

Chen, Tsing-Chang

2003-06-01

The monsoon circulation, which is generally considered to be driven by the landmass-ocean thermal contrast, like a gigantic land-sea breeze circulation, exhibits a phase reversal in its vertical structure; a monsoon high aloft over a continental thermal low is juxtaposed with a midoceanic trough underlaid by an oceanic anticyclone. This classic monsoon circulation model is well matched by the monsoon circulation depicted with the observational data prior to the First Global Atmospheric Research Program (GARP) Global Experiment (FGGE). However, synthesizing findings of the global circulation portrayed with the post-FGGE data, it was found that some basic features of major monsoon circulations in Asia, North America, South America, and Australia differ from those of the classic monsoon circulation model. Therefore, a revision of the classic monsoon theory is suggested. With four different wave regimes selected to fit the horizontal dimensions of these monsoon circulations, basic features common to all four major monsoons are illustrated in terms of diagnostic analyses of the velocity potential maintenance equation (which relates diabatic heating and velocity potential) and the streamfunction budget (which links velocity potential and streamfunction) in these wave regimes. It is shown that a monsoon circulation is actually driven by the east-west differential heating and maintained dynamically by a balance between a vorticity source and advection. This dynamic balance is reflected by a spatial quadrature relationship between the monsoon divergent circulation and the monsoon high (low) at upper (lower) levels.

Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

NASA Astrophysics Data System (ADS)

Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

2009-04-01

The past 5 Ma were marked by systematic shifts towards colder climates and concomitant reorganizations in ocean circulation and marine heat transports. Some of the changes involved plate-tectonic shifts such as the closure of the Panamanian Isthmus and restructuring of the Indonesian archipelago that affected inter-ocean communications and altered the world ocean circulation. These changes induced ocean-atmosphere feedbacks with consequences for climates globally and locally. Two new ICDP and IODP drilling initiatives target these developments from the perspectives of marine and terrestrial palaeoclimatology and the human evolution. The ICDP drilling initiative HSPDP ("Hominid Sites and Paleolakes Drilling Project"; ICDP ref. no. 10/07) targets lacustrine depocentres in Ethiopia (Hadar) and Kenya (West Turkana, Olorgesailie, Magadi) to retrieve sedimentary sequences close to the places and times where various species of hominins lived over currently available outcrop records. The records will provide a spatially resolved record of the East African environmental history in conjunction with climate variability at orbital (Milankovitch) and sub-orbital (ENSO decadal) time scales. HSPDP specifically aims at (1) compiling master chronologies for outcrops around each of the depocentres; (2) assessing which aspects of the paleoenvironmental records are a function of local origin (hydrology, hydrogeology) and which are linked with regional or larger-scale signals; (3) correlating broad-scale patterns of hominin phylogeny with the global beat of climate variability and (4) correlating regional shifts in the hominin fossil and archaeological record with more local patterns of paleoenvironmental change. Ultimately the aim is to test hypotheses that link physical and cultural adaptations in the course of the hominin evolution to local environmental change and variability. The IODP initiative SAFARI ("Southern African Climates, Agulhas Warm Water Transports and Retroflection, and Interocean Exchanges"; IODP ref. no. 702-full) aims at deciphering the late Neogene ocean history of the SW Indian Ocean. SAFARI specifically targets the Agulhas Current in the SW Indian Ocean that constitutes the strongest western boundary current in the southern hemisphere oceans. The Current transports warm and saline surface waters from the tropical Indian Ocean to the southern tip of Africa. Exchanges with the atmosphere influence eastern and southern African climates including individual weather systems such as extra-tropical cyclone formation in the region and rainfall patterns. Ocean models further suggest the "leakage" of Agulhas water around South Africa into the Atlantic potentially modulates the Atlantic meridional overturning circulation (MOC) with consequences for climate globally. The SAFARI drilling initiative aims to retrieve a suite of long drill cores along the southeast African margin and in the Indian-Atlantic ocean gateway. SAFARI will shed light on the history of Agulhas Current warm water transports along the southeast African margin during the late Neogene and its linking with ocean-climate developments. Specific objectives of SAFARI are to test (1) the sensitivity of the Agulhas Current to changing climates of the Plio/Pleistocene, including upstream forcing linked with equatorial Indian Ocean changes and Indonesian Throughflow; (2) the Current's influence on eastern and southern Africa climates, including rain fall patterns and vegetation changes; (3) buoyancy transfer to the Atlantic by Agulhas leakage around southern Africa, and (4) the contribution of variable Agulhas Leakage to shifts of the Atlantic MOC during episodes of major ocean and climate reorganizations of the past 5 Ma. These studies will provide insight into the Current's influence on eastern and southern African terrestrial climates, including its possible impact on the late Neogene evolution of large mammals including hominids. The ICDP and IODP drilling campaigns will enable us to establish the linkages between the ocean climatology of the SW Indian and terrestrial climates of Eastern Africa during key periods of global climate change. Combining the ICDP records of East African terrestrial climate at key hominin sites with IODP records of marine climate variability at the SE African continental margin will help to test if pulses of hominin evolutionary innovation were linked with periods of enhanced variability of local terrestrial environments and marine climatology of the Indian Ocean. * co-PIs of the ICDP initiative HSPDP are A.S. Cohen, R. Arrowsmith, A.K. Behrensmeyer, C. Feibel, R. Johnson, Z. Kubsa, D. Olago, R. Potts, R. Renaut * co-PIs of the IODP initiative SAFARI are R. Zahn, I. Hall, R. Schneider, M. Á. Bárcena, S. Barker, A. Biastoch, Chr. Charles, J. Compton, R. Cowling, P. Diz, L. Dupont, J.-A. Flores, S. Goldstein, S. Hemming, K. Holmgren, J. Lee-Thorp, G. Knorr, C. Lear, A. Mazaud, G. Mortyn, F. Peeters, B. Preu, R. Rickaby, J. Rogers, A. Rosell-Mele, Chr. Reason, V. Spiess, M. Trauth, G. Uenzelmann-Neben, S. Weldeab, P. Ziveri

Application of Formation Testing While Drilling (GeoTap) for acquiring formation pressure data from the Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic

NASA Astrophysics Data System (ADS)

Amirov, Elnur

2016-04-01

A new technology to acquire wireline quality pressure tests using a Logging While Drilling approach has been successfully implemented few years ago in Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic. The Formation Tester While Drilling tool (GeoTap) uses a testing sequence similar to wireline tools. A single probe is extended to the borehole wall and a small pretest volume withdrawn from the formation. The resulting pressure transient is then analyzed for formation pressure, formation permeability and mobility information. Up-link and down-link capabilities have been added to achieve test control and quality feedback. An efficient downlink algorithm is used downhole to analyze the data. The parameters and pressure data are transmitted to the surface in real-time for continuous monitoring of the test. More detailed pressure data is recorded and retrieved after returning to surface. Use of a quartz gauge allows excellent accuracy. Azeri, Chirag and Guneshli fields consist of layered sand reservoirs alternation with shale sequences and detailed pressure data is acquired on a high percentage of wells in order to understand lateral and vertical continuity of different flow units. The formation tester can be utilized with the 'triple combo' Logging While Drilling string which eliminates the need to rig up wireline on many wells. Wireline formation tester runs are time consuming - particularly if high deviation or high overbalance conditions are encountered requiring pipe conveyed techniques. Non-Productive Time is high when the wireline tools are stuck and fishing operations are required. The Sperry Drilling GeoTap formation pressure tester service provides real-time formation pressure measurements. It bridges the critical gap between drilling safety and optimization, by providing early and reliable measurements of key reservoir properties, while improving reservoir understanding and completion design in real time. The GeoTap tester obtains direct pore-pressure measurements as the well is being drilled, with accuracy and precision comparable to that of wireline testers. The GeoTap service can eliminate the time, risk, and cost associated with running pipe-conveyed wireline test tools. It also measures annular and bore pressure while drilling, providing accurate, continuous, real-time hydrostatic pressure, and equivalent circulating density (ECD) information. This aids in determining and maintaining optimal mud weight, reduces formation damage, increases the rate of penetration, and increases operational safety. GeoTap benefits can be improvement of formation evaluation, real-time fluid gradients and fluid mobility (permeability/viscosity indicator), identification of fluid contact points, determination of reservoir connectivity/compartmentalization and depletion, increase safety of operation, determination of optimal mud weight and manage of ECD. We can also continuously monitor wellbore stability for assessments in order to reduce formation damage which in turns will help to increase drilling effectiveness (determine precise overbalance for maximizing ROP and continuously monitor hole-cleaning effectiveness with pressure-while-drilling, while reducing formation damage due to swab/surge). Save time and money by reducing rig down time associated with wireline testing. GeoTap Tool capable of performing more than 150 pressure tests per run and optional orientation of pressure measurement is available (top, right, bottom or left). GeoTap testing has been completed with encouraging results in many wells up to circa 3000m deep. Data has been acquired successfully both in a "Drill-Test-Drill' mode and a "Post-Drill-Test" mode. GeoTap tests have spanned wide ranges of borehole temperature, pressure, mobility as well as formation permeability and overbalance conditions. GeoTap tests in Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic have proved that a logging while drilling approach can be successfully employed to acquire formation pressure data in open hole (which is also very useful for fluid gradient analysis, oil water and gas oil contacts delineation/identification).

Higher circulating leukocytes in women with PCOS is reversed by aerobic exercise.

PubMed

Covington, Jeffrey D; Tam, Charmaine S; Pasarica, Magdalena; Redman, Leanne M

2016-05-01

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance, elevated circulating leukocytes, and hypothesized to have higher adipose tissue inflammation. Aerobic exercise reduces circulating leukocytes and improves insulin sensitivity in obese individuals, but the effect of exercise on inflammation in PCOS is not known. We investigated circulating leukocytes, insulin sensitivity by euglycemic-hyperinsulinemic clamp, serum pro- and anti-inflammatory markers (hsCRP, TNF-α, total and high molecular weight adiponectin), and abdominal subcutaneous adipose tissue (SAT) gene expression of proinflammatory markers in 8 PCOS women and 8 obese control females matched for BMI. Additionally, in a prospective study, the 8 women with PCOS underwent a 16-week aerobic exercise regimen with the same measures performed post-intervention. Compared to controls, white blood cell counts (WBC) were 30% higher (p = 0.04) and circulating total adiponectin levels were 150% lower (p = 0.03) in women with PCOS at baseline/pre-exercise conditions. SAT gene expression of macrophage migration inhibitory factor (MIF, p < 0.01) and interleukin-6 (IL-6, p < 0.05) were also lower in women with PCOS. In response to 16 weeks of aerobic exercise, insulin sensitivity improved (p < 0.01) and WBC counts decreased (p = 0.02). The exercise-induced change in WBC and circulating neutrophils correlated inversely with changes in glucose disposal rate (r = -0.73, p = 0.03; and r = -0.82, p = 0.01, respectively). Aerobic exercise reduced serum leptin (p < 0.05) after 4 weeks, trended to reduce the ratio of leptin-to-high molecular weight adiponectin (p < 0.1) by the 8th week, and significantly increased serum dehydroepiandrosterone sulfate (DHEA-S, p < 0.001) after 16 weeks. In conclusion, women with PCOS have higher circulating leukocytes compared to controls, which can be reversed by aerobic exercise and is associated with improvements in insulin sensitivity. Copyright © 2014 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Sensitivity of Middle Atmospheric Temperature and Circulation in the UIUC Mesosphere-Stratosphere-Troposphere GCM to the Treatment of Subgrid-Scale Gravity-Wave Breaking

NASA Technical Reports Server (NTRS)

Yang, Fanglin; Schlesinger, Michael E.; Andranova, Natasha; Zubov, Vladimir A.; Rozanov, Eugene V.; Callis, Lin B.

2003-01-01

The sensitivity of the middle atmospheric temperature and circulation to the treatment of mean- flow forcing due to breaking gravity waves was investigated using the University of Illinois at Urbana-Champaign 40-layer Mesosphere-Stratosphere-Troposphere General Circulation Model (MST-GCM). Three GCM experiments were performed. The gravity-wave forcing was represented first by Rayleigh friction, and then by the Alexander and Dunkerton (AD) parameterization with weak and strong breaking effects of gravity waves. In all experiments, the Palmer et al. parameterization was included to treat the breaking of topographic gravity waves in the troposphere and lower stratosphere. Overall, the experiment with the strong breaking effect simulates best the middle atmospheric temperature and circulation. With Rayleigh friction and the weak breaking effect, a large warm bias of up to 60 C was found in the summer upper mesosphere and lower thermosphere. This warm bias was linked to the inability of the GCM to simulate the reversal of the zonal winds from easterly to westerly crossing the mesopause in the summer hemisphere. With the strong breaking effect, the GCM was able to simulate this reversal, and essentially eliminated the warm bias. This improvement was the result of a much stronger meridional transport circulation that possesses a strong vertical ascending branch in the summer upper mesosphere, and hence large adiabatic cooling. Budget analysis indicates that 'in the middle atmosphere the forces that act to maintain a steady zonal-mean zonal wind are primarily those associated with the meridional transport circulation and breaking gravity waves. Contributions from the interaction of the model-resolved eddies with the mean flow are small. To obtain a transport circulation in the mesosphere of the UIUC MST-GCM that is strong enough to produce the observed cold summer mesopause, gravity-wave forcing larger than 100 m/s/day in magnitude is required near the summer mesopause. In the tropics, only with the AD parameterization can the model produce realistic semiannual oscillations.

Materials for geothermal production

NASA Astrophysics Data System (ADS)

Kukacka, L. E.

Advances in the development of new materials continue to be made in the geothermal materials project. Many successes have already been accrued and the results used commercially. In FY-91, work was focused on reducing well drilling, fluid transport and energy conversion costs. Specific activities performed included lightweight CO2 resistant well cements, thermally conductive and scale resistant protective liner systems, chemical systems for lost circulation control, corrosion mitigation in process components at The Geysers, and elastomer-metal bonding systems. Efforts to transfer the technologies developed in these efforts to other energy-related sectors of the economy continued, and considerable success was achieved.

Temporary Cementitious Sealers in Enhanced Geothermal Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugama T.; Pyatina, T.; Butcher, T.

2011-12-31

Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. Thesemore » fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper-try sealers. Two specific additives without sodium silicate as alkaline additive were developed in this project: One additive was the sodium carboxymethyl cellulose (CMC) as self-degradation promoting additive; the other was the hard-burned magnesium oxide (MgO) made from calcinating at 1,000-1,500 C as an expansive additive. The AASC and AASF cementitious sealers made by incorporating an appropriate amount of these additives met the following six criteria: 1) One dry mix component product; 2) plastic viscosity, 20 to 70 cp at 300 rpm; 3) maintenance of pumpability for at least 1 hour at 85 C; 4) compressive strength >2000 psi; 5) self-degradable by injection with water at a certain pressure; and 6) expandable and swelling properties; {ge}0.5% of total volume of the sealer.« less

Rock magnetic properties in the sulfate reduction zone in IODP 350 Hole 1437B, Izu Bonin rear arc: preliminary results

NASA Astrophysics Data System (ADS)

Musgrave, R. J.; Kars, M. A. C.; Kodama, K.

2014-12-01

During the northern Spring 2014 (April-May), IODP Expedition 350 drilled a 1806.5 m deep hole at Site U1437 in the Izu-Bonin rear arc, in order to understand, among other objectives, the compositional evolution of the arc since the Miocene and track the missing half of the subduction factory. The good recovery of mostly fine grained sediments at this site enables a high resolution paleomagnetic and rock magnetic study. Particularly, variations in magnetic properties and mineralogy are well documented. The onboard magnetostratigraphy established from the study of the archive halves highlighted remagnetized intervals that produced "ghost" repetitions of geomagnetic reversals ~10's meters below their actual stratigraphic position in specific intervals. Onboard paleo- and rock magnetic analyses showed that remagnetization is probably due to a chemical remanence carried by iron sulfides (putatively identified as greigite). The rock magnetic parameters, SIRM/k and the S-ratio are consistent with the presence of ferromagnetic iron sulfides in Site U1437. A mixture of iron oxides and iron sulfides was found within the sulfate reduction zone, which was identified by onboard pore water analyses at ~50-60 meters below sea floor (mbsf) by a minimum in sulfate (~5 mM) coupled with a maximum in alkalinity. Below 50 mbsf, the sulfate content increases up to ~29 mM at ~460 mbsf. The particular downhole profile of the sulfate content in Site U1437 is probably triggered by fluid circulation. Evolution of sulfate content, pyritization process and fluid circulation are closely linked. Onshore research is focusing on further downhole characterization of the iron sulfides including their abundance, grain size and composition. Routine magnetic properties (NRM, magnetic susceptibility) and rock magnetic analyses at high resolution (every ~20-50 cm), including hysteresis properties and low temperature magnetic measurements, have been conducted on about 400 discrete samples in the first 200 m of Hole 1437B (Cores 1H to 30X). As suggested by the onboard data, hysteresis measurements showed the occurrence of both single domain-pseudo single domain iron oxides and iron sulfides in the sulfate reduction zone. Preliminary results will be compared with the geochemical data.

Atlantic Ocean Circulation and Climate: The Current View From the Geological Record

NASA Astrophysics Data System (ADS)

Curry, W.

2006-12-01

Several recent advances in our understanding of past ocean circulation come from geological reconstructions using deep sea sediment proxies of water mass structure and flow. Put together, the observations suggest that the Atlantic Ocean during the last glacial period (21,000 years ago) was very different from today. Geochemical tracers document a shoaling of North Atlantic Deep Water and a much greater volume of deep waters with an Antarctic origin. Sedimentary pore water profiles have detected a reversal in the salinity gradient between northern and southern deep water sources. Uranium-series decay products in North Atlantic sediments indicate that the southward transport of North Atlantic Deep Water was as much as 30-40% reduced from today's transport. Ocean-margin density reconstructions are consistent with a one third reduction in transport through the Florida Straits. A reversed cross-basin density gradient in the South Atlantic calls for a different intermediate water circulation in the South Atlantic. The glacial Atlantic circulation appears to be best explained by a reduced influence of North Atlantic deep water sources and much greater influence of Antarctic deep water sources. More recent changes in Atlantic circulation have been much more modest. During the Little Ice Age (LIA - a much smaller cooling event about 200 to 600 years ago), transport of the Florida Current was reduced by about 10%, significant but a much smaller reduction than observed during the glacial period. There is little evidence for a change in the distribution or geochemistry of the water masses during the LIA. For both climate events (the glacial and the LIA) reduced Florida Current transport was accompanied by increased salinity of its surface waters, linking changes in ocean circulation to large scale changes in surface water hydrology. A feedback between the circulation of the Atlantic Ocean and the climate of the tropics has been proposed before and also seen in some coupled climate models: variations in the temperature gradients in the Atlantic basin affect the position of the Intertropical Convergence Zone and alter evaporation and precipitation patterns in the tropics. The salinity anomalies caused by these atmospheric shifts eventually are transported back to high latitudes by ocean circulation (Vellinga and Wu, 2004). Several recent geological reconstructions appear to observe such a coupling on centennial and millennial time scales.

Surface mapping and drilling of extinct seafloor massive sulphide deposits (eSMS) from the TAG Hydrothermal Field, 26oN: A tale of two `Jaspers'

NASA Astrophysics Data System (ADS)

Stobbs, I. J.; Lusty, P.; Petersen, S.; Murton, B. J.

2017-12-01

Two extinct seafloor massive sulphide (eSMS) deposits within the TAG hydrothermal field, 26oN, mid-Atlantic ridge, were mapped and drilled: Southern Mound and the newly discovered `Rona Mound'. Surface mapping was undertaken by combining high definition video footage and high resolution bathymetry to interpret surface geological and geomorphological features. Drill core was recovered using the BGS RD2 robotic drilling rig. Surface mapping of the mounds revealed a superficial cover of carbonate and iron-oxyhydroxides sediments, observed to directly overly oxide coated sulphide material within fault scarps, which dissect the flanks of both mounds. Drilling at the summits of the mounds revealed similar stratigraphy to the mapping, with the addition of a coherent and dense layer of red-coloured silica-rich `jasper', up to 3m thick, underlying the sediments and overlying unoxidised massive sulphides. The jasper mineralogy is dominated by silica, with minor iron oxides and rare disseminated sulphides. It displays a range of complex textures including filamentous and dendritic iron oxides often coated in silica. Drill core samples show the material to be porous, but relatively impermeable. Strong and positive Eu (REE) anomalies indicates a hydrothermal origin with little evidence of a seawater signature (lack of negative Ce anomaly). Silica precipitation is associated with low temperature hydrothermal activity, chert and jasper materials are locally present within the nearby hydrothermally active TAG mound and are more widespread at low-temperature diffuse hydrothermal sites such as within the MESO field. We interpret the `jasper' layers to be a common product, formed during the waning, low temperature, stage of the hydrothermal cycle which may form an impermeable and resistant `cap' that protects the underlying massive sulphide ore body from oxidation and dissolution. The formation of a `jasper cap' could act automatically to preserve eSMS deposits when hydrothermal circulation ceases and is essential to preserving the resource potential of eSMS deposits. This `jasper' capping layer is important from an economic perspective, and reinforces the need for shallow sub-seafloor mapping as part of any deep-sea mineral exploration. This research received funding from the EC FP7 project Blue Mining (604500).

Tectonics and geology of spreading ridge subduction at the Chile Triple Junction: a synthesis of results from Leg 141 of the Ocean Drilling Program

USGS Publications Warehouse

Behrmann, J.H.; Lewis, S.D.; Cande, S.C.

1994-01-01

An active oceanic spreading ridge is being subducted beneath the South American continent at the Chile Triple Junction. This process has played a major part in the evolution of most of the continental margins that border the Pacific Ocean basin. A combination of high resolution swath bathymetric maps, seismic reflection profiles and drillhole and core data from five sites drilled during Ocean Drilling Program (ODP) Leg 141 provide important data that define the tectonic, structural and stratigraphic effects of this modern example of spreading ridge subduction. A change from subduction accretion to subduction erosion occurs along-strike of the South American forearc. This change is prominently expressed by normal faulting, forearc subsidence, oversteepening of topographic slopes and intensive sedimentary mass wasting, overprinted on older signatures of sediment accretion, overthrusting and uplift processes in the forearc. Data from drill sites north of the triple junction (Sites 859-861) show that after an important phase of forearc building in the early to late Pliocene, subduction accretion had ceased in the late Pliocene. Since that time sediment on the downgoing oceanic Nazca plate has been subducted. Site 863 was drilled into the forearc in the immediate vicinity of the triple junction above the subducted spreading ridge axis. Here, thick and intensely folded and faulted trench slope sediments of Pleistocene age are currently involved in the frontal deformation of the forearc. Early faults with thrust and reverse kinematics are overprinted by later normal faults. The Chile Triple Junction is also the site of apparent ophiolite emplacement into the South American forearc. Drilling at Site 862 on the Taitao Ridge revealed an offshore volcanic sequence of Plio-Pleistocene age associated with the Taitao Fracture Zone, adjacent to exposures of the Pliocene-aged Taitao ophiolite onshore. Despite the large-scale loss of material from the forearc at the triple junction, ophiolite emplacement produces a large topographic promontory in the forearc immediately after ridge subduction, and represents the first stage of forearc rebuilding. ?? 1994 Springer-Verlag.

The scale of hydrothermal circulation of the Iheya-North field inferred from intensive heat flow measurements and ocean drilling

NASA Astrophysics Data System (ADS)

Masaki, Y.; Kinoshita, M.; Yamamoto, H.; Nakajima, R.; Kumagai, H.; Takai, K.

2014-12-01

Iheya-North hydrothermal field situated in the middle Okinawa trough backarc basin is one of the largest ongoing Kuroko deposits in the world. Active chimneys as well as diffuse ventings (maximum fluid temperature 311 °C) have been located and studied in detail through various geological and geophysical surveys. To clarify the spatial scale of the hydrothermal circulation system, intensive heat flow measurements were carried out and ~100 heat flow data in and around the field from 2002 to 2014. In 2010, Integrated Ocean Drilling Program (IODP) Expedition 331 was carried out, and subbottom temperature data were obtained around the hydrothermal sites. During the JAMSTEC R/V Kaiyo cruise, KY14-01 in 2014, Iheya-North "Natsu" and "Aki" hydrothermal fields were newly found. The Iheya-Noth "Natsu" and "Aki" sites are located 1.2 km and 2.6 km south from the Iheya-North original site, respectively, and the maximum venting fluid temperature was 317 °C. We obtained one heat flow data at the "Aki" site. The value was 17 W/m2. Currently, the relationship between these hydrothermal sites are not well known. Three distinct zones are identified by heat flow values within 3 km from the active hydrothermal field. They are high-heat flow zone (>1 W/m2; HHZ), moderate-heat-flow zone (1-0.1 W/m2; MHZ); and low-heat-flow zone (<0.1 W/m2; LHZ). With increasing distance east of the HHZ, heat flow gradually decreases towards MHZ and LHZ. In the LHZ, temperature at 37m below the seafloor (mbsf) was 6 °C, that is consistent with the surface low heat flow suggesting the recharge of seawater. However, between 70 and 90 mbsf, the coarser sediments were cored, and temperature increased from 25 °C to 40°C. The temperature was 905°C at 151 mbsf, which was measured with thermoseal strips. The low thermal gradient in the upper 40 m suggests downward fluid flow. We infer that a hydrothermal circulation in the scale of ~1.5 km horizontal vs. ~a few hundred meters vertical.

Flow reversal and thermal limit in a heated rectangular channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, L.Y.; Tichler, P.R.; Yang, B.W.

The thermal limit in a vertical rectangular channel was determined in a series of experiments whereby the internal coolant underwent a change in flow direction from forced downflow to upward natural circulation. The tests were designed to simulate the flow reversal transient in the High Flux Beam Reactor. A number of parameters were varied in the flow reversal experiments to examine their effects on the thermal limit. Among the parameters varied were the rate of flow coastdown, inlet subcooling, water level in the upper plenum, bypass ratio (ratio of initial flow through the heated section to initial flow through themore » bypass orifice), and single- verses double-sided heating.« less

Computational analysis of hybrid Norwood circulation with distal aortic arch obstruction and reverse Blalock-Taussig shunt.

PubMed

Ceballos, Andres; Argueta-Morales, I Ricardo; Divo, Eduardo; Osorio, Ruben; Caldarone, Christopher A; Kassab, Alain J; Decampli, William M

2012-11-01

The hemodynamics characteristics of the hybrid Norwood (HN) procedure differ from those of the conventional Norwood and are not fully understood. We present a multiscale model of HN circulation to understand local hemodynamics and effects of aortic arch stenosis and a reverse Blalock-Taussig shunt (RBTS) on coronary and carotid perfusion. Four 3-dimensional models of four HN anatomic variants were developed, with and without 90% distal preductal arch stenosis and with and without a 4-mm RBTS. A lumped parameter model of the circulation was coupled to a local 3-dimensional computational fluid dynamics model. Outputs from the lumped parameter model provided waveform boundary conditions for the computational fluid dynamics model. A 90% distal arch stenosis reduced pressure and net flow-rate through the coronary and carotid arteries by 30%. Addition of the RBTS completely restored pressure and flow rate to baseline in these vessels. Zones of flow stagnation, flow reversal, and recirculation in the presence of stenosis were rendered more orderly by addition of the RBTS. In the absence of stenosis, presence of the shunt resulted in extensive zones of disturbed flow within the RBTS and arch. We found that a 4-mm × 21-mm RBTS completely compensated for the effects of a 90% discrete stenosis of the distal aortic arch in the HN. Placed preventatively, the RBTS and arch displayed zones with thrombogenic potential showing recirculation and stagnation that persist for a substantial fraction of the cardiac cycle, indicating that anticoagulation should be considered with a prophylactic RBTS. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Influence of the Minho River plume on the Rias Baixas (NW of the Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Sousa, M. C.; Vaz, N.; Alvarez, I.; Gomez-Gesteira, M.; Dias, J. M.

2014-11-01

The buoyancy generated by the Minho estuarine plume can flood the Rias Baixas for long periods, reversing the normal salinity gradients. Thus, the main purpose of this work was to study the propagation of Minho estuarine plume to the Rias Baixas, establishing the wind and river discharge conditions in which this plume affects the circulation and hydrography features of these coastal systems as well as the plume characteristics under the most probable forcing conditions, through the application of the numerical model MOHID. For this purpose, several scenarios with different river discharges and wind were simulated. The numerical results revealed that the Minho estuarine plume responds rapidly to wind variations and is influenced by coastline geometry. Under Minho River discharges higher than 700 m3 s- 1 and weak northward winds (3 m s- 1) the circulation patterns of the Rias de Vigo and Pontevedra are reversed. On the other hand, moderate northward winds (6 m s- 1) combined with Minho River discharges higher than 200 m3 s- 1, 300 m3 s- 1 and 700 m3 s- 1 reverse the circulation pattern of the Rias de Vigo, Pontevedra and Arousa, respectively. Under the same conditions, the water exchange between Rias Baixas was analyzed using a particle-tracking model following the trajectories of particles released close to the Minho River mouth. Over 5 days, under Minho River discharges higher than 2100 m3 s- 1 combined with northward winds of 6 m s- 1, an intense water exchange between Rias was observed. However, only 20% of the particles found in Ria de Pontevedra come directly from the Minho River.

The Neogene equatorial Pacific: A view from 2009 IODP drilling on Expedition 320/321. (Invited)

NASA Astrophysics Data System (ADS)

Lyle, M. W.; Shackford, J.; Holbourn, A. E.; Tian, J.; Raffi, I.; Pälike, H.; Nishi, H.

2013-12-01

The equatorial Pacific responds strongly to global climate and is a source of ENSO, the largest global decadal climate oscillation. Equatorial Pacific circulation and upwelling result from global atmospheric circulation patterns so it is unsurprising that oceanographic changes in the equatorial Pacific reverberate globally. IODP expedition 320/321 (Pacific Equatorial Age Transect) drilled 8 sites to reconstruct a 50-million-year record of ocean change for the equatorial Pacific. The resulting record, when spliced together, will resolve orbital variations through most of the Cenozoic. All sedimentary sequences have now been scanned by XRF, so that biogeochemical changes through the Cenozoic can be studied. Here we report data from IODP Sites U1335, U1336, U1337, and U1338, the Neogene part of the PEAT megasplice. Sediments of the Neogene equatorial Pacific are primarily biogenic carbonates, with about 15% biogenic silica tests and 5% assorted other components, including clays. Typically, highest sediment deposition occurs when plate tectonic movement carries a drill site underneath the equatorial zone, indicating that equatorial upwelling and high productivity have been consistent features of the Neogene equatorial Pacific. Sedimentation rates become significantly slower and dissolution of both biogenic carbonates and silica are more pronounced when sites are beyond 3° in latitude away from the equator, as biogenic sediment production drops but dissolution does not. The differences between equatorial and off-equator sites allow assessment of productivity vs dissolution as drivers of the sediment record. Carbonate dissolution can also be assessed by a ratio of XRF-estimated carbonate to dissolution resistant biogenic residue, like barite. There is a common stratigraphy of carbonate variation in the Neogene equatorial Pacific, as proposed by earlier work from DSDP Leg 85 and ODP Leg 138. The new Exp 320/321 drilling extends the high-resolution record from ~0-5 Ma covered by Leg 138 studies to the full Neogene. Productivity events, like those in the late Miocene biogenic bloom interval (~5-7 Ma), are marked by carbonate percent lows at sites near the equator where diatom production outstrips increased production by carbonate producers. Away from the equator, there is little sign of the events in the percentage data because carbonate production increases in step with biogenic silica production at lower productivity increases. The middle-late Miocene carbonate crash interval (12-8 Ma) is marked by enhanced deposition of mat-forming diatioms, but highest deposition of bio-SiO2 is at the convergence of equatorial currents at 2°N, not at the equator. It is still unclear to what extent productivity shapes the events versus dissolution. Other productivity events can now be associated with middle Miocene Mi3-Mi4 glaciations. Dissolution events are also found, like the early Miocene ';lavender' event at 17 Ma. Surprisingly, peak dissolution is not associated with the peak warmth of the Miocene climatic optimum, but with an abrupt early warming that predates the warm interval. The dissolution event also predates possible volatile release from Columbia River flood basalts, indicating that complex changes in circulation and ocean carbon content must have occurred then. Understanding the timing will ultimately help to decipher the role of the carbon cycle in climate change.

Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka

PubMed Central

An, Zhisheng; Colman, Steven M.; Zhou, Weijian; Li, Xiaoqiang; Brown, Eric T.; Jull, A. J. Timothy; Cai, Yanjun; Huang, Yongsong; Lu, Xuefeng; Chang, Hong; Song, Yougui; Sun, Youbin; Xu, Hai; Liu, Weiguo; Jin, Zhangdong; Liu, Xiaodong; Cheng, Peng; Liu, Yu; Ai, Li; Li, Xiangzhong; Liu, Xiuju; Yan, Libin; Shi, Zhengguo; Wang, Xulong; Wu, Feng; Qiang, Xiaoke; Dong, Jibao; Lu, Fengyan; Xu, Xinwen

2012-01-01

Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32 ka, reflecting the interplay of these two systems. These records document the anti-phase relationship of the Westerlies and the ASM for both glacial-interglacial and glacial millennial timescales. During the last glaciation, the influence of the Westerlies dominated; prominent dust-rich intervals, correlated with Heinrich events, reflect intensified Westerlies linked to northern high-latitude climate. During the Holocene, the dominant ASM circulation, punctuated by weak events, indicates linkages of the ASM to orbital forcing, North Atlantic abrupt events, and perhaps solar activity changes. PMID:22943005

Upward extension of the Nankai accretionary prism megasplay fault into slope basin strata. Insights from drilling at IODP Expedition 338 Site C0022

NASA Astrophysics Data System (ADS)

Fabbri, O.; Oohashi, K.; Kanagawa, K.; Yamaguchi, A.

2013-12-01

Megasplay faults have been recognized on seismic reflection profiles across several convergent margins in the world. Understanding the behavior of these faults during large to very large inter-plate earthquakes is a major challenge in assessing strong-motion and tsunami hazards at or near subduction zones. One of the goals of the IODP NanTroSEIZE project is to drill across and to obtain data from the megasplay fault crossing the Nankai accretionary prism off Kii peninsula (Kumano transect), SW Japan. This fault is considered to have been activated during the 1944 Tonankai earthquake (Baba et al., 2006 ; Moore et al., 2007). Drilling and coring during IODP Expedition 316 (Expedition 316 Scientists, 2009) showed that the megasplay fault at 300 mbsf at Site C0004 consists in a 60 m thick package of fractured and brecciated rocks. Combined analysis of 3D reflection data in the vicinity of Site C0004 and core data from sites C0004 and C0008 (Strasser et al., 2009 ; Kimura et al., 2011) suggest that the lower boundary of the megasplay fault ceased activity at about 1.55 Ma while its upper boundary has remained active since about 1.95 Ma and probably 1.24 Ma. In order to determine whether the megasplay fault upper boundary crosscuts slope sediments or is sealed by them, drilling at IODP Site C0022 was carried out during Expedition 338. Two 420 m deep holes were drilled: C0022A (LWD) and C0022B (coring). At Hole C0022A, LWD resistivity images show that the 85-105.5 mbsf interval is fractured and extends above and below a ca. 1 m thick interval characterized by a low resistivity value at 100-101 mbsf. Structures observed in cores from Hole C0022B confirm LWD data. While gently dipping elsewhere, bedding in the 73-146 mbsf interval is steep, commonly exceeding 30°. This bedding dip increase may be a consequence of fault activity (folding ?). Though the low-resistivity interval at 100-101 mbsf could not be sampled at Hole C0022B (no recovery between 95.5 and 99.5 mbsf), cores immediately from above this interval show three ca. 2 cm thick zones of claystone characterized by a marked planar fabric bearing faint striations raking at about 90°. Preliminary biostratigraphic dating in Hole C0022B indicate age reversals at 80.5, 137.5 and 145.5 mbsf, suggesting reverse offset bringing older strata over younger strata. Drilling at IODP Site C0022 confirms that a branch of the megasplay fault previously cored at Expedition 316 Site C0004 extends upwards and southeastwards. The core zone of this branch lies at about 100 mbsf and is about 1 m thick. The presence of weakly foliated claystone suggests aseismic motion immediately above the core zone. The lack of samples from the core zone prevents to determine whether motion was aseismic or not.

Global Sea Surface Temperature and Ecosystem Change Across the Mid-Miocene Climatic Optimum

NASA Astrophysics Data System (ADS)

Veenstra, T. J. T.; Bakker, V. B.; Sangiorgi, F.; Peterse, F.; Schouten, S.; Sluijs, A.

2016-12-01

Even though the term Mid-Miocene Climatic Optimum (MMCO; ca. 17 to 14 Ma) has been widely used in the literature since the early 1990's, almost no early-middle Miocene sea surface temperature (SST) proxy records have been published that support climate warming across its onset. Benthic (and diagenetically altered planktic) foram δ18O records show a decrease, suggesting (deep) ocean warming and/or Antarctic ice sheet melting. However, reliable absolute SST proxy records are absent from the tropics and very scarce in temperate and polar regions. This leaves the question if the warmth of the MMCO was truly global and how its onset relates to the widely recorded positive (Monterey) carbon isotope excursion and volcanism. Finally, it remains uncertain how marine ecosystems responded to this hypothesized warming. We present organic biomarker SST proxy records (Uk'37 and TEX86) spanning the MMCO for several locations in the Atlantic and Pacific Ocean along a pole-to-pole transect, including Ocean Drilling Program Site 959 in the eastern Tropical Atlantic, ODP Site 643 in the Norwegian Sea, ODP Site 1007 on the Great Bahama Bank and Integrated Ocean Drilling Program Site U1352 off New Zealand. Additionally, we use marine palynology (mostly dinoflagellate cysts) to assess ecosystem change at these locations. The resulting spatial reconstruction of SST change shows that Middle Miocene warming was global. Nevertheless, the records also show distinct regional variability, including relatively large warming in the Norwegian Sea and a damped signal in the southern hemisphere, suggesting pronounced changes in ocean circulation. The onset of the MMCO was marked by prominent changes in ecological and depositional setting at the studied sites, likely also related to ocean circulation changes.

Three-dimensional hydrodynamic modelling study of reverse estuarine circulation: Kuwait Bay.

PubMed

Alosairi, Y; Pokavanich, T; Alsulaiman, N

2018-02-01

Hydrodynamics and associated environmental processes have always been of major concern to coastal-dependent countries, such as Kuwait. This is due to the environmental impact that accompanies the economic and commercial activities along the coastal areas. In the current study, a three-dimensional numerical model is utilized to unveil the main dynamic and physical properties of Kuwait Bay during the critical season. The model performance over the summer months (June, July and August 2012) is assessed against comprehensive field measurements of water levels, velocity, temperature and salinity data before using the model to describe the circulation as driven by tides, gravitational convection and winds. The results showed that the baroclinic conditions in the Bay are mainly determined by the horizontal salinity gradient and to much less extent temperature gradient. The gradients stretched over the southern coast of the Bay where dense water is found at the inner and enclosed areas, while relatively lighter waters are found near the mouth of the Bay. This gradient imposed a reversed estuarine circulation at the main axis of the Bay, particularly during neap tides when landward flow near the surface and seaward flow near the bed are most evident. The results also revealed that the shallow areas, including Sulaibikhat and Jahra Bays, are well mixed and generally flow in the counter-clockwise direction. Clockwise circulations dominated the northern portion of the Bay, forming a sort of large eddy, while turbulent fields associated with tidal currents were localized near the headlands. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acute consumption of flavanol-rich cocoa and the reversal of endothelial dysfunction in smokers.

PubMed

Heiss, Christian; Kleinbongard, Petra; Dejam, Andrè; Perré, Sandra; Schroeter, Hagen; Sies, Helmut; Kelm, Malte

2005-10-04

This study was designed to assess the effect of flavanol-rich food on the circulating pool of bioactive nitric oxide (NO) and endothelial dysfunction in smokers. Studies suggest that smoking-related vascular disease is caused by impaired NO synthesis and that diets rich in flavanols can increase bioactive NO in plasma. In smokers (n = 11), the effects of flavanol-rich cocoa on circulating NO species in plasma (RXNO) measured by reductive gas-phase chemiluminescence and endothelial function as assessed by flow-mediated dilation (FMD) were characterized in a dose-finding study orally administering cocoa containing 88 to 370 mg flavanols and in a randomized double-blind crossover study using 100 ml cocoa drink with high (176 to 185 mg) or low (<11 mg) flavanol content on two separate days. In addition to cocoa drink, ascorbic acid and NO-synthase inhibitor L-NMMA (n = 4) were applied. There were significant increases in RXNO (21 +/- 3 nmol/l to 29 +/- 5 nmol/l) and FMD (4.5 +/- 0.8% to 6.9 +/- 0.9%, each p < 0.05) at 2 h after ingestion of 176 to 185 mg flavanols, a dose potentially exerting maximal effects. These changes correlated with increases in flavanol metabolites. Cocoa-associated increases in RXNO and FMD were reversed by L-NMMA. Ascorbic acid had no effect. The circulating pool of bioactive NO and endothelium-dependent vasodilation is acutely increased in smokers following the oral ingestion of a flavanol-rich cocoa drink. The increase in circulating NO pool may contribute to beneficial vascular health effects of flavanol-rich food.

Impact of particulate sediment, bentonite and barite (oil-drilling waste) on net fluxes of oxygen and nitrogen in Arctic-boreal sponges.

PubMed

Fang, James K H; Rooks, Christine A; Krogness, Cathinka M; Kutti, Tina; Hoffmann, Friederike; Bannister, Raymond J

2018-07-01

To meet the increasing global energy demand, expanding exploration for oil and gas reserves as well as associated drilling activities are expected in the Arctic-boreal region where sponge aggregations contribute to up to 90% of benthic biomass. These deep-water sponges along with their microbial endobionts play key roles in the nitrogen cycling in Arctic-boreal ecosystems. This study aimed to investigate the effects of drilling discharges and associated sediment resuspension events on net fluxes of oxygen, ammonium, nitrate and nitrite in three common deep-water sponge species in the form of explants. Sponges were exposed to suspended bentonite and barite, the primary particulate compounds in drilling waste, as well as suspended natural sediment particles for a period of 33 days (on average 10 mg L -1 for 12 h day -1 ). The exposure period was followed by a pollution abatement period for a further 33 days. No sponge mortality was observed during the experiment. However, exposure to these particles, especially to barite, led to reduced oxygen consumption by up to 33% that was linearly correlated with reduced nitrite/nitrate release by the sponges. The changes in net fluxes were accompanied by decreased tissue oxygenation by up to 54% within the sponges. These findings reveal the effects of fine particles on sponge metabolic processes by reducing aerobic respiration and microbial nitrification, and possibly by favouring anaerobic processes such as microbial denitrification. Most of the sponge responses recovered to their control levels upon the pollution abatement period, but the effects caused by barite may not be reversible. Our findings provide the first insight into the ecological consequences of oil and gas drilling activities on sponge-mediated nitrogen cycling in the Arctic-boreal region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multifunctional High Drug Loading Nanocarriers for Cancer Drug Delivery

NASA Astrophysics Data System (ADS)

Jin, Erlei

2011-12-01

Most anticancer drugs have poor water-solubility, rapid blood clearance, low tumor-selectivity and severe systemic toxicity to healthy tissues. Thus, polymeric nanocarriers have been widely explored for anticancer drugs to solve these problems. However, polymer nanocarriers developed to date still suffer drawbacks including low drug loading contents, premature drug release, slow cellular internalization, slow intracellular drug release and thereby low therapeutic efficiency in cancer thermotherapy. Accordingly, in this dissertation, functional nanocapsules and nanoparticles including high drug loading liposome-like nanocapsules, high drug loading phospholipid-mimic nanocapsules with fast intracellular drug release, high drug loading charge-reversal nanocapsules, TAT based long blood circulation nanoparticles and charge-reversal nuclear targeted nanoparticles are designed and synthesized. These functional carriers have advantages such as high drug loading contents without premature drug release, fast cellular internalization and intracellular drug release, nuclear targeted delivery and long blood circulation. As a result, all these drug carriers show much higher in vitro and in vivo anti-cancer activities.

[Oxygen consumption in the lungs and systemic circulation--different methods of measurement of one data or different data?].

PubMed

Perfilova, A V; Gromova, T A; Lebedinskiĭ, K M; Zaĭchik, A M

2014-01-01

The article deals with calculation of oxygen consumption in the lungs by means of breathing gas mixture analysis and in parallel--in the systemic circulation by reverse Fick method; 32 paired measurements were performed in 8 patients after cardiac surgery with cardiopulmonary bypass. The mean pulmonary oxygen consumption was higher than the same value calculated by the reverse Fick principle--148.4 +/- 39.9 ml x min(-1) x m(-2) and 120 +/- 35.1 ml x min(-1) x m(-2), respectively, the mean difference between two methods was 28.4 +/- 18.4 ml x min(-1) x m(-2). However, in two observations the interrelation was inversed. While analyzing physiological and methodological reasons for these differences, the authors concluded that, despite both methods can be used in monitoring systemic oxygen transport in the critically ill, they are not interchangeable, and valuable additional data could be derived from fast changes in lungs oxygen uptake.

Reconsidering Volcanic Ocean Island Hydrology: Recent Geophysical and Drilling Results

NASA Astrophysics Data System (ADS)

Thomas, D. M.; Pierce, H. A.; Lautze, N. C.

2017-12-01

Recent results of geophysical surveys and exploratory drilling in Hawaii have suggested that Hawaii's hydrogeology may be more complex than has been generally recognized. Instead of a more-or-less homogeneous pile of highly permeable eruptive basalts that are intermittently punctuated by volcanic dikes confined to calderas and rift zones, we are finding that dike compartmentalization is occurring outside of recognized rift zones, leading to significantly higher volumes of stored groundwater within the island. Analysis of recent geophysical surveys have shown local water table elevations that are substantially higher than can be accounted for by the high hydraulic conductivities of Hawaiian basalts. Recent diamond wireline drilling results have also shown that sub-horizontal variations in permeability, associated with significant changes in eruptive character (e.g. explosive vs effusive activity) are acting as significant perching and confining bodies over significant aerial extents and suggest that these features also contribute to increased storage of recharge. Not only is storage much higher than previously assumed, these features appear to impact subsurface groundwater flow in ways that are not accounted for in traditional methods of computing sustainable yields for near shore aquifers: where buried confining formations extend to depths well below sea level, higher elevation recharge is being intercepted and diverted to deep submarine groundwater discharge well below depths that are typically investigated or quantified. We will provide a summary of the recent geophysical survey results along with a revised conceptual model for groundwater circulation within volcanic ocean islands.

Computer Simulation To Assess The Feasibility Of Coring Magma

NASA Astrophysics Data System (ADS)

Su, J.; Eichelberger, J. C.

2017-12-01

Lava lakes on Kilauea Volcano, Hawaii have been successfully cored many times, often with nearly complete recovery and at temperatures exceeding 1100oC. Water exiting nozzles on the diamond core bit face quenches melt to glass just ahead of the advancing bit. The bit readily cuts a clean annulus and the core, fully quenched lava, passes smoothly into the core barrel. The core remains intact after recovery, even when there are comparable amounts of glass and crystals with different coefficients of thermal expansion. The unique resulting data reveal the rate and sequence of crystal growth in cooling basaltic lava and the continuous liquid line of descent as a function of temperature from basalt to rhyolite. Now that magma bodies, rather than lava pooled at the surface, have been penetrated by geothermal drilling, the question arises as to whether similar coring could be conducted at depth, providing fundamentally new insights into behavior of magma. This situation is considerably more complex because the coring would be conducted at depths exceeding 2 km and drilling fluid pressures of 20 MPa or more. Criteria that must be satisfied include: 1) melt is quenched ahead of the bit and the core itself must be quenched before it enters the barrel; 2) circulating drilling fluid must keep the temperature of the coring assembling cooled to within operational limits; 3) the drilling fluid column must nowhere exceed the local boiling point. A fluid flow simulation was conducted to estimate the process parameters necessary to maintain workable temperatures during the coring operation. SolidWorks Flow Simulation was used to estimate the effect of process parameters on the temperature distribution of the magma immediately surrounding the borehole and of drilling fluid within the bottom-hole assembly (BHA). A solid model of the BHA was created in SolidWorks to capture the flow behavior around the BHA components. Process parameters used in the model include the fluid properties and temperature of magma, coolant flow rate, rotation speed, and rate of penetration (ROP). The modeling results indicate that there are combinations of process parameters that will provide sufficient cooling to enable the desired coring process in magma.

Spectral reflectance analysis of hydrothermal alteration in drill chips from two geothermal fields, Nevada

NASA Astrophysics Data System (ADS)

Lamb, A. K.; Calvin, W. M.

2010-12-01

We surveyed drill chips with a lab spectrometer in the visible-near infrared (VNIR) and short-wave infrared (SWIR) regions, 0.35-2.5 μm, to evaluate hydrothermal alteration mineralogy of samples from two known geothermal fields in western Nevada. Rock is fractured into small pieces or “chips” during drilling and stored in trays by depth interval. The drill chips are used to determine subsurface properties such as lithology, structure, and alteration. Accurately determining alteration mineralogy in the geothermal reservoir is important for indicating thermal fluids (usually associated with fluid pathways such as faults) and the highest temperature of alteration. Hydrothermal minerals, including carbonates, iron oxides, hydroxides, sheet silicates, and sulfates, are especially diagnostic in the VNIR-SWIR region.. The strength of reflectance spectroscopy is that it is rapid and accurate for differentiating temperature-sensitive minerals that are not visually unique. We examined drill chips from two western Nevada geothermal fields: Hawthorne (two wells) and Steamboat Springs (three wells) using an ASD lab spectrometer with very high resolution. The Steamboat Hills geothermal field has produced electricity since 1988 and is well studied, and is believed to be a combination of extensional tectonics and magmatic origin. Bedrocks are Cretaceous granodiorite intruding into older metasediments. Hot springs and other surface expressions occur over an area of about 2.6 km2. In contrast, the Hawthorne geothermal reservoir is a ‘blind’ system with no surface expressions such as hot springs or geysers. The geothermal field is situated in a range front fault zone in an extensional area, and is contained in Mesozoic mixed granite and meta-volcanics. We collected spectra at each interval in the chip trays. Interval length varied between 10’ and 30’. - Endmember analysis and mineral identification were performed -using standard analysis approaches used to map mineralogy in remote sensing data sets. Mapped by depth, we identified narrow zones of intense alteration that mark fluid circulation, and overall changes in metamorphic grade facies through clay type. Steamboat Hills is more highly altered than Hawthorne, thus the alteration assemblages reflect the pH and temperature differences.

Geoethical Approach to Antarctic Subglacial Lakes Exploration

NASA Astrophysics Data System (ADS)

Talalay, Pavel; Markov, Alexey; Sysoev, Mikhail

2014-05-01

Antarctic subglacial aquatic environment have become of great interest to the science community because they may provide unique information about microbial evolution, the past climate of the Earth, and the formation of the Antarctic ice sheet. Nowadays it is generally recognized that a vast network of lakes, rivers, and streams exists thousands of meters beneath Antarctic Ice Sheets. Up to date only four boreholes accessed subglacial aquatic system but three of them were filled with high-toxic drilling fluid, and the subglacial water was contaminated. Two recent exploration programs proposed by UK and USA science communities anticipated direct access down to the lakes Ellsworth and Whillans, respectively, in the 2012/2013 Antarctic season. A team of British scientists and engineers engaged in the first attempt to drill into Lake Ellsworth but failed. US research team has successfully drilled through 800 m of Antarctic ice to reach a subglacial lake Whillans and retrieve water and sediment samples. Both activities used hot-water drilling technology to access lakes. Hot water is considered by the world science community as the most clean drilling fluid medium from the present point of view but it cannot solve environmental problems in total because hot-water even when heated to 90 °C, filtered to 0.2 μm, and UV treated at the surface could pick up microorganisms from near-surface snow and circulate them in great volume through the borehole. Another negative impact of hot-water circulation medium is thermal pollution of subglacial water. The new approach to Antarctic subglacial lakes exploration is presented by sampling technology with recoverable autonomous sonde which is equipped by two hot-points with heating elements located on the bottom and top sides of the sonde. All down-hole sonde components will be sterilized by combination of chemical wash, HPV and UV sterilization prior using. At the beginning of the summer season sonde is installed on the surface of the Antarctic ice sheet above subglacial lake. All equipment is got into working trim, the bottom hot-point is powered, and the sonde starts to melt down to the ice sheet bed. The personnel leave the site, and all further operations are going on in semi-automatic mode. The melted water does not recover from the hole and refreezes behind the sonde. Electric line for power supply and communication with down-hole sensors is released from the coil installed inside the sonde. Since the sonde enters into the subglacial lake, it samples the water and examines subglacial conditions. After sampling, the motor connected with coil is switched on, and the top hot-point is put into action. The sonde begins to recover itself to the surface by spooling the cable and melting overlying ice with the help of the upper hot-point. Since 8-9 months from starting, the sonde reaches the surface and waits the personnel for servicing and moving to the next site. The big advantage of the proposed technology is that subglacial lake would be measured and sampled while subglacial water is reliably isolated from surface environment.

The use of additive ceramic hollow spheres on cement slurry to prevent lost circulation in formation `X' having low pressure fracture

NASA Astrophysics Data System (ADS)

Rita, Novia; Mursyidah, Syahindra, Michael

2018-03-01

When drilling, if the hydrostatic pressure is higher than formation pressure (fracture pressure) it will cause lost circulation during cementing process. To solve this problem, hydrostatic pressure of slurry can be decreased by lowering the slurry density by using some additives. Ceramic Hollow Spheres (CHS) is lightweight additive. This additive comes with low specific gravity so it can lowered the slurry density. When the low-density slurry used in cementing process, it can prevent low circulation and fractured formation caused by cement itself. Class G cement is used in this experiment with the standard density of this slurry is 15.8 ppg. With the addition of CHS, slurry density lowered to 12.5 ppg. CHS not only used to lower the slurry density, it also used to make the same properties with the standard slurry even the density has been lowered. Both thickening time and compressive strength have not change if the CHS added to the slurry. With addition of CHS, thickening time at 70 Bc reached in 03 hours 12 minutes. For the compressive strength, 2000 psi reached in 07 hours 07 minutes. Addition of CHS can save more time in cementing process of X formation.

Refining the Subseafloor Circulation Model of the Middle Valley Hydrothermal System Using Fluid Geochemistry

NASA Astrophysics Data System (ADS)

Inderbitzen, K. E.; Wheat, C. G.; Baker, P. A.; Fisher, A. T.

2014-12-01

Currently, fluid circulation patterns and the evolution of rock/fluid compositions as circulation occurs in subseafloor hydrothermal systems are poorly constrained. Sedimented spreading centers provide a unique opportunity to study subsurface flow because sediment acts as an insulating blanket that traps heat from the cooling magma body and limits: (a) potential flow paths for seawater to recharge the aquifer in permeable upper basaltic basement and (b) points of altered fluid egress. This also allows for a range of thermal and geochemical gradients to exist near the sediment-water interface. Models of fluid circulation patterns in this type of hydrologic setting have been generated (eg. Stein and Fisher, 2001); however fluid chemistry datasets have not previously been used to test the model's viability. We address this issue by integrating the existing circulation model with fluid compositional data collected from sediment pore waters and high temperature hydrothermal vents located in Middle Valley on the Juan de Fuca Ridge. Middle Valley hosts a variety of hydrologic regimes: including areas of fluid recharge (Site 855), active venting (Site 858/1036; Dead Dog vent field), recent venting (Site 856/1035; Bent Hill Massive Sulfide deposit) and a section of heavily sedimented basement located between recharge and discharge sites (Site 857). We will present new results based on thermal and geochemical data from the area of active venting (Sites 858 and 1036), that was collected during Ocean Drilling Program Legs 139 and 169 and a subsequent heat flow/gravity coring effort. These results illuminate fine scale controls on secondary recharge and fluid flow within the sediment section at Site 858/1036. The current status of high temperature vents in this area (based on observations made in July, 2014) will also be outlined.

Orbital, tectonic and oceanographic controls on Pliocene climate and atmospheric circulation in Arctic Norway

NASA Astrophysics Data System (ADS)

Panitz, Sina; Salzmann, Ulrich; Risebrobakken, Bjørg; De Schepper, Stijn; Pound, Matthew J.; Haywood, Alan M.; Dolan, Aisling M.; Lunt, Daniel J.

2018-02-01

During the Pliocene Epoch, a stronger-than-present overturning circulation has been invoked to explain the enhanced warming in the Nordic Seas region in comparison to low to mid-latitude regions. While marine records are indicative of changes in the northward heat transport via the North Atlantic Current (NAC) during the Pliocene, the long-term terrestrial climate evolution and its driving mechanisms are poorly understood. We present the first two-million-year-long Pliocene pollen record for the Nordic Seas region from Ocean Drilling Program (ODP) Hole 642B, reflecting vegetation and climate in Arctic Norway, to assess the influence of oceanographic and atmospheric controls on Pliocene climate evolution. The vegetation record reveals a long-term cooling trend in northern Norway, which might be linked to a general decline in atmospheric CO2 concentrations over the studied interval, and climate oscillations primarily controlled by precession (23 kyr), obliquity (54 kyr) and eccentricity (100 kyr) forcing. In addition, the record identifies four major shifts in Pliocene vegetation and climate mainly controlled by changes in northward heat transport via the NAC. Cool temperate (warmer than present) conditions prevailed between 5.03-4.30 Ma, 3.90-3.47 Ma and 3.29-3.16 Ma and boreal (similar to present) conditions predominated between 4.30-3.90 Ma, 3.47-3.29 and after 3.16 Ma. A distinct decline in sediment and pollen accumulation rates at c. 4.65 Ma is probably linked to changes in ocean currents, marine productivity and atmospheric circulation. Climate model simulations suggest that changes in the strength of the Atlantic Meridional Overturning Circulation during the Early Pliocene could have affected atmospheric circulation in the Nordic Seas region, which would have affected the direction of pollen transport from Scandinavia to ODP Hole 642B.

Clay minerals related to the circulation of geothermal fluids in boreholes at Rittershoffen (Alsace, France)

NASA Astrophysics Data System (ADS)

Vidal, Jeanne; Patrier, Patricia; Genter, Albert; Beaufort, Daniel; Dezayes, Chrystel; Glaas, Carole; Lerouge, Catherine; Sanjuan, Bernard

2018-01-01

Two geothermal wells, GRT-1 and GRT-2, were drilled into the granite at Rittershoffen (Alsace, France) in the Upper Rhine Graben to exploit geothermal resources at the sediment-basement interface. Brine circulation occurs in a permeable fracture network and leads to hydrothermal alteration of the host rocks. The goal of the study was to characterize the petrography and mineralogy of the altered rocks with respect to the permeable fracture zones in the granitic basement. As clay minerals are highly reactive to hydrothermal alteration, they can be used as indicators of present-day and paleo-circulation systems. Special attention has been paid to the textural, structural and chemical properties of these minerals. The fine-grained clay fraction (< 5 μm) was analyzed around the originally permeable fracture zones to observe the crystal structure of clay minerals using X-ray diffraction. Chemical microanalysis of the clay minerals was performed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The occurrences of mixed layers illite-smectite ( 10% smectite) provide a promising guide for identifying the fracture zones that control the present-day circulation of geothermal fluids in the Rittershoffen wells. However, multistage paleo-circulation systems could lead to an abundance of heterogeneous and fine-grained illitic minerals that could plug the fracture system. The permeability of fracture zones in the GRT-1 well was likely reduced because of an intense illitization, and the well was stimulated. The occurrence of chlorite in the permeable fracture zones of GRT-2 is indicative of less intense illitization, and the natural permeability is much higher in GRT-2 than in GRT-1.

Geology and geochemistry of newly discovered Tertiary carbonatite occurrences near Villa Ahumada area, Basin and Range province, Chihuahua, northern Mexico

NASA Astrophysics Data System (ADS)

Nandigam, Ravi Chenchu

This study targets some newly discovered carbonatite occurrences located in the eastern Mexican Basin and Range province, a few kilometers to the east of Villa Ahumada, Chihuahua. The region containing these occurrences experienced compression related to subduction of the Farallon plate until about 32 Ma that was followed by Basin and Range extension. Geological mapping (1:5,000 scale), petrography, study of drill hole cuttings and satellite images, and major and trace element chemical analyses were utilized to understand the intrusive style of the carbonatites, their mineralogy and petrogenesis. The carbonatites, named Yuca, Mariana and El Indio, collectively intrude limestones, granitic intrusives and subduction-related tuffs and lavas mainly as a stock, breccias and dikes. The Yuca carbonatite was emplaced as a 900-m diameter stock, 500 x 350 m breccia body, numerous dikes and networks of fracture fillings. Crosscutting field relationships at Yuca suggest at least two stages of carbonatite emplacement. At Mariana, carbonatite was emplaced as a 750 x 350 m breccia. Four out of nine reverse circulation drill holes penetrated and bottomed in the breccia at an average depth of about 300 m At El Indio, carbonatite was emplaced as a 20 m diameter breccia pipe and a 1m thick sill. Major minerals present are calcite, Fe-rich calcite and hematite. Sporadic presence of fluorite is common. At Mariana, two generations of grossular-rich garnets associated with limestones and granite porphyry respectively are recognized. It is inferred that garnets in granite porphyry represent metasomatic alteration due to the emplacement of carbonatite breccia. Parental magmas of Yuca carbonatites have undergone differentiation under low fO2 conditions during which they were progressively enriched in iron. The carbonatite compositional types recognized based on major element data, in the sequence of least to most highly differentiated, are (1) magnesio-, (2) calcio- and (3) ferrocarbonatites. The concentrations of thorium, uranium, niobium, yttrium and rare earth elements increase with differentiation. Carbonatites are associated with up to 20000 times enrichment of lanthanum and cerium with respect to chondrite. Finally, the Mariana carbonatite breccia is associated with about 7,928,550 short tons of rock with a grade of 0.14% SigmaREE, and primitive mantle normalized trace element plots of carbonatites indicate a mantle origin of their parental melts.

Two-dimensional modeling of thermal inversion layers in the middle atmosphere of Mars

NASA Technical Reports Server (NTRS)

Theodore, B.; Chassefiere, E.

1993-01-01

There is some evidence that the thermal structure of the martian middle atmosphere may be altered in a significant way by the general circulation motions. Indeed, while it is well known that the circulation in the meridional plane is responsible for the reversal of the latitudinal thermal gradient at the solstice through the adiabatic heating due to sinking motions above the winter pole, here we want to emphasize that a likely by-product effect could be the formation of warm layers, mainly located in the winter hemisphere, and exhibiting an inversion of the vertical thermal gradient.

Co-firing of paper mill sludge and coal in an industrial circulating fluidized bed boiler.

PubMed

Tsai, Meng-Yuan; Wu, Keng-Tung; Huang, Chin-Cheng; Lee, Hom-Ti

2002-01-01

Co-firing of coal and paper mill sludge was conducted in a 103 MWth circulating fluidized bed boiler to investigate the effect of the sludge feeding rate on emissions of SOx, NOx, and CO. The preliminary results show that emissions of SOx and Nx decrease with increasing sludge feeding rate, but CO shows the reverse tendency due to the decrease in combustion temperature caused by a large amount of moisture in the sludge. All emissions met the local environmental requirements. The combustion ashes could be recycled as feed materials in the cement manufacturing process.

Test of Time-Reversal Invariance at COSY (TRIC)

NASA Astrophysics Data System (ADS)

Eversheim, D.; Valdau, Yu.; Lorentz, B.

2016-02-01

At the Cooler Synchrotron COSY a novel (P-even, T-odd) null test of time-reversal invariance to an accuracy of 10-6 is planned as an internal target transmission experiment. The parity conserving time-reversal violating observable is the total cross-section asymmetry Ay,xz. This quantity is measured using a polarized proton beam with an energy of 135 MeV and an internal tensor polarized deuteron target from the PAX atomic beam source. The reaction rate will be determined by the lifetime of the beam. Consequently, the accuracy of the current measurement of the circulating proton beam is crucial for this experiment. Thus, the cooler synchroton ring serves as an ideal forward spectrometer, as a detector, and an accelerator.

Studies on the liver sequestration of lymphocytes bearing membrane-associated galactose-terminal glycoconjugates: reversal with agents that effectively compete for the asialoglycoprotein receptor.

PubMed

Samlowski, W E; Spangrude, G J; Daynes, R A

1984-10-15

The removal of "effete" glycoproteins from the circulation represents a proposed physiologic role for the hepatocyte asialoglycoprotein receptor. Our experiments support the hypothesis that this receptor may also be directly involved in the removal from the circulation of cells bearing asialoglycoconjugates. We report that the enhanced liver localization of neuraminidase-treated lymphocytes can be competitively inhibited by the coinjection of asialofetuin (ASF). Fetuin itself was without effect. Competitive inhibition of the liver receptor allowed normal localization to lymphoid tissues of the enzyme-treated lymphocytes, a condition which persisted as long as free ASF was present in the circulation. Our studies support the concept that cell surface carbohydrates play an important role in the tissue distribution of circulating lymphocytes. The process of thymocyte maturation, bone marrow transplantation, and the adoptive immunotherapy with continuous T-cell lines represent conditions where recirculation potential may be influenced by the presence of galactose terminal glycoconjugates.

On-chip microwave circulators using quantum Hall plasmonics

NASA Astrophysics Data System (ADS)

Mahoney, Alice; Colless, James; Pauka, Sebastian; Hornibrook, John; Doherty, Andrew; Reilly, David; Peeters, Lucas; Fox, Eli; Goldhaber-Gordon, David; Kou, Xuefeng; Pan, Lei; Wang, Kang; Watson, John; Gardner, Geoffrey; Manfra, Michael

Circulators are directional circuit elements integral to technologies including radar systems, microwave communication transceivers and the readout of quantum information devices. Their non-reciprocity commonly arises from the interference of microwaves over the centimetre-scale of the signal wavelength in the presence of bulky magnetic media that breaks time-reversal symmetry. We present a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, `slow-light' response of a GaAs/AlGaAs 2-dimensional electron gas in the quantum Hall regime. Further, by implementing this circulator design on a thin film of a magnetic topological insulator (Cr0.12(Bi0.26Sb0.62)2Te3), we show that similar non-reciprocity can be achieved at zero magnetic field. This additional mode of operation serves as a non-invasive probe of edge states in the quantum anomalous Hall effect, while also extending the possibility for integration with superconducting devices.

Magnetic insights on seismogenic processes from scientific drilling of fault

NASA Astrophysics Data System (ADS)

Ferre, E. C.; Chou, Y. M.; Aubourg, C. T.; Li, H.; Doan, M. L.; Townend, J.; Sutherland, R.; Toy, V.

2017-12-01

Modern investigations through scientific drilling of recently seismogenic faults have provided remarkable insights on the physics of rupture processes. Following devastating earthquakes, several drilling programs focused since 1995 on the Nojima, Chelungpu, San Andreas, Wenchuan, Nankai Trough, Japan Trench and New Zealand Alpine faults. While these efforts were all crowned with success largely due to the multidisciplinarity of investigations, valuable insights were gained from rock magnetism and paleomagnetism and deserve to be highlighted. Continuous logging of magnetic properties allows detection of mineralogical and chemical changes in the host rock and fault zone particularly in slip zones, whether these are caused by frictional melting, elevation of temperature, ultracataclasis, or post-seismic fluid rock interaction. Further magnetic experiments on discrete samples including magnetic susceptibility, natural remanent magnetization, hysteresis properties, isothermal remanent magnetization acquisition and first order reversal curves, provide additional constrains on the nature, concentration and grain size of magnetic carriers. These experiments typically also inform on magnetization processes by thermal, chemical, or electrical mechanisms. Magnetic fabrics are generally not investigated on fault rocks from drill cores primarily in an effort to conserve the recovered core. However, recent methodological developments now would allow chemically non-destructive anisotropy of magnetic susceptibility (AMS) measurements to be performed on small 3.5 mm cubes. The mini-AMS method could provide crucial information on the kinematics of frictional melts produced during recent or ancient earthquakes and therefore would constrain the corresponding focal mechanisms. Finally, demagnetization experiments of the natural remanent magnetization (NRM) are one of the most powerful items in the magnetic toolkit because they provide chronological constrains on magnetization processes. Hence paleomagnetic experiments on fault rocks offer a unique opportunity to distinguish between recently active and ancient slip zones.

South China Sea Tectonics and Magnetics: Constraints from IODP Expedition 349 and Deep-tow Magnetic Surveys

NASA Astrophysics Data System (ADS)

Lin, J.; Li, C. F.; Kulhanek, D. K.; Zhao, X.; Liu, Q.; Xu, X.; Sun, Z.; Zhu, J.

2014-12-01

The South China Sea (SCS) is the largest low-latitude marginal sea in the world. Its formation and evolution are linked to the complex continental-oceanic tectonic interaction of the Eurasian, Pacific, and Indo-Australian plates. Despite its relatively small size and short history, the SCS has undergone nearly a complete Wilson cycle from continental break-up to seafloor spreading to subduction. In January-March 2014, Expedition 349 of the International Ocean Discovery Program (IODP) drilled five sites in the deep basin of the SCS. Three sites (U1431, U1433, and U1434) cored into oceanic basement near the fossil spreading center on the East and Southwest Subbasins, whereas Sites U1432 and U1435 are located near the northern continent/ocean boundary of the East Subbasin. Shipboard biostratigraphy based on microfossils preserved in sediment directly above or within basement suggests that the preliminary cessation age of spreading in both the East and Southwest Subbasins is around early Miocene (16-20 Ma); however, post-cruise radiometric dating is being conducted to directly date the basement basalt in these subbasins. Prior to the IODP drilling, high-resolution near-seafloor magnetic surveys were conducted in 2012 and 2013 in the SCS with survey lines passing near the five IODP drilling sites. The deep-tow surveys revealed detailed patterns of the SCS magnetic anomalies with amplitude and spatial resolutions several times better than that of traditional sea surface measurements. Preliminary results reveal several episodes of magnetic reversal events that were not recognized by sea surface measurements. Together the IODP drilling and deep-tow magnetic surveys provide critical constraints for investigating the processes of seafloor spreading in the SCS and evolution of a mid-ocean ridge from active spreading to termination.

The ICDP Snake River Geothermal Drilling Project: preliminary overview of borehole geophysics

USGS Publications Warehouse

Schmitt, Douglas R.; Liberty, Lee M.; Kessler, James E.; Kuck, Jochem; Kofman, Randolph; Bishop, Ross; Shervais, John W.; Evans, James P.; Champion, Duane E.

2012-01-01

Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand the geothermal systems in three locations across the Snake River Plain with varying geological and hydrological structure. An extensive series of standard and specialized geophysical logs were obtained in each of the wells. Hydrogen-index neutron and γ-γ density logs employing active sources were deployed through the drill string, and although not fully calibrated for such a situation do provide semi-quantitative information related to the ‘stratigraphy’ of the basalt flows and on the existence of alteration minerals. Electrical resistivity logs highlight the existence of some fracture and mineralized zones. Magnetic susceptibility together with the vector magnetic field measurements display substantial variations that, in combination with laboratory measurements, may provide a tool for tracking magnetic field reversals along the borehole. Full waveform sonic logs highlight the variations in compressional and shear velocity along the borehole. These, together with the high resolution borehole seismic measurements display changes with depth that are not yet understood. The borehole seismic measurements indicate that seismic arrivals are obtained at depth in the formations and that strong seismic reflections are produced at lithological contacts seen in the corresponding core logging. Finally, oriented ultrasonic borehole televiewer images were obtained over most of the wells and these correlate well with the nearly 6 km of core obtained. This good image log to core correlations, particularly with regards to drilling induced breakouts and tensile borehole and core fractures will allow for confident estimates of stress directions and or placing constraints on stress magnitudes. Such correlations will be used to orient in core orientation giving information useful in hydrological assessments, paleomagnetic dating, and structural volcanology.

Experimental Study of Quantum Graphs With and Without Time-Reversal Invariance

NASA Astrophysics Data System (ADS)

Anlage, Steven Mark; Fu, Ziyuan; Koch, Trystan; Antonsen, Thomas; Ott, Edward

An experimental setup consisting of a microwave network is used to simulate quantum graphs. The random coupling model (RCM) is applied to describe the universal statistical properties of the system with and without time-reversal invariance. The networks which are large compared to the wavelength, are constructed from coaxial cables connected by T junctions, and by making nodes with circulators time-reversal invariance for microwave propagation in the networks can be broken. The results of experimental study of microwave networks with and without time-reversal invariance are presented both in frequency domain and time domain. With the measured S-parameter data of two-port networks, the impedance statistics and the nearest-neighbor spacing statistics are examined. Moreover, the experiments of time reversal mirrors for networks demonstrate that the reconstruction quality can be used to quantify the degree of the time-reversal invariance for wave propagation. Numerical models of networks are also presented to verify the time domain experiments. We acknowledge support under contract AFOSR COE Grant FA9550-15-1-0171 and the ONR Grant N000141512134.

The behavioural consequences of sex reversal in dragons

PubMed Central

Li, Hong; Holleley, Clare E.; Elphick, Melanie; Georges, Arthur

2016-01-01

Sex differences in morphology, physiology, and behaviour are caused by sex-linked genes, as well as by circulating sex-steroid levels. Thus, a shift from genotypic to environmental sex determination may create an organism that exhibits a mixture of male-like and female-like traits. We studied a lizard species (Central Bearded Dragon, Pogona vitticeps), in which the high-temperature incubation of eggs transforms genetically male individuals into functional females. Although they are reproductively female, sex-reversed dragons (individuals with ZZ genotype reversed to female phenotype) resemble genetic males rather than females in morphology (relative tail length), general behaviour (boldness and activity level), and thermoregulatory tactics. Indeed, sex-reversed ‘females’ are more male-like in some behavioural traits than are genetic males. This novel phenotype may impose strong selection on the frequency of sex reversal within natural populations, facilitating rapid shifts in sex-determining systems. A single period of high incubation temperatures (generating thermally induced sex reversal) can produce functionally female individuals with male-like (or novel) traits that enhance individual fitness, allowing the new temperature-dependent sex-determining system to rapidly replace the previous genetically based one.

Ocean and atmosphere feedbacks affecting AMOC hysteresis in a GCM

NASA Astrophysics Data System (ADS)

Jackson, L. C.; Smith, R. S.; Wood, R. A.

2017-07-01

Theories suggest that the Atlantic Meridional Overturning Circulation (AMOC) can exhibit a hysteresis where, for a given input of fresh water into the north Atlantic, there are two possible states: one with a strong overturning in the north Atlantic (on) and the other with a reverse Atlantic cell (off). A previous study showed hysteresis of the AMOC for the first time in a coupled general circulation model (Hawkins et al. in Geophys Res Lett. doi: 10.1029/2011GL047208, 2011). In this study we show that the hysteresis found by Hawkins et al. (2011) is sensitive to the method with which the fresh water input is compensated. If this compensation is applied throughout the volume of the global ocean, rather than at the surface, the region of hysteresis is narrower and the off states are very different: when the compensation is applied at the surface, a strong Pacific overturning cell and a strong Atlantic reverse cell develops; when the compensation is applied throughout the volume there is little change in the Pacific and only a weak Atlantic reverse cell develops. We investigate the mechanisms behind the transitions between the on and off states in the two experiments, and find that the difference in hysteresis is due to the different off states. We find that the development of the Pacific overturning cell results in greater atmospheric moisture transport into the North Atlantic, and also is likely responsible for a stronger Atlantic reverse cell. These both act to stabilize the off state of the Atlantic overturning.

Reversible Reprogramming of Circulating Memory T Follicular Helper Cell Function during Chronic HIV Infection

PubMed Central

Cubas, Rafael; van Grevenynghe, Julien; Wills, Saintedym; Kardava, Lela; Santich, Brian H.; Buckner, Clarisa M.; Muir, Roshell; Tardif, Virginie; Nichols, Carmen; Procopio, Francesco; He, Zhong; Metcalf, Talibah; Ghneim, Khader; Locci, Michela; Ancuta, Petronella; Routy, Jean-Pierre; Trautmann, Lydie; Li, Yuxing; McDermott, Adrian B.; Koup, Rick A.; Petrovas, Constantinos; Migueles, Steven A.; Connors, Mark; Tomaras, Georgia D.; Moir, Susan; Crotty, Shane

2015-01-01

Despite the overwhelming benefits of antiretroviral therapy (ART) in curtailing viral load in HIV-infected individuals, ART does not fully restore cellular and humoral immunity. HIV-infected individuals under ART show reduced responses to vaccination and infections and are unable to mount an effective antiviral immune response upon ART cessation. Many factors contribute to these defects, including persistent inflammation, especially in lymphoid tissues, where T follicular helper (Tfh) cells instruct and help B cells launch an effective humoral immune response. In this study we investigated the phenotype and function of circulating memory Tfh cells as a surrogate of Tfh cells in lymph nodes and found significant impairment of this cell population in chronically HIV-infected individuals, leading to reduced B cell responses. We further show that these aberrant memory Tfh cells exhibit an IL-2–responsive gene signature and are more polarized toward a Th1 phenotype. Treatment of functional memory Tfh cells with IL-2 was able to recapitulate the detrimental reprogramming. Importantly, this defect was reversible, as interfering with the IL-2 signaling pathway helped reverse the abnormal differentiation and improved Ab responses. Thus, reversible reprogramming of memory Tfh cells in HIV-infected individuals could be used to enhance Ab responses. Altered microenvironmental conditions in lymphoid tissues leading to altered Tfh cell differentiation could provide one explanation for the poor responsiveness of HIV-infected individuals to new Ags. This explanation has important implications for the development of therapeutic interventions to enhance HIV- and vaccine-mediated Ab responses in patients under ART. PMID:26546609

Completion Report for Well ER-2-2 Corrective Action Unit 97: Yucca Flat/Climax Mine, Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wurtz, Jeffrey

Well ER-2-2 was drilled for the U.S. Department of Energy, Nevada National Security Administration Nevada Field Office in support of the Underground Test Area (UGTA) Activity. The well was drilled from January 17 to February 8, 2016, as part of the Corrective Action Investigation Plan (CAIP) for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada. The primary purpose of the well was to collect hydrogeologic data to evaluate uncertainty in the flow and transport conceptual model and its contamination boundary forecasts, and to detect radionuclides in groundwater from the CALABASH (U2av) underground test. Well ER-2-2 was notmore » completed as planned due to borehole stability problems. As completed, the well includes a piezometer (p1) to 582 meters (m) (1,909 feet [ft]) below ground surface (bgs) installed in the Timber Mountain lower vitric-tuff aquifer (TMLVTA) and a 12.25-inch (in.) diameter open borehole to 836 m (2,743 ft) bgs in the Lower tuff confining unit (LTCU). A 13.375-in. diameter carbon-steel casing is installed from the surface to a depth of 607 m (1,990 ft) bgs. Data collected during borehole construction include composite drill cutting samples collected every 3.0 m (10 ft), geophysical logs to a depth of 672.4 m (2,206 ft) bgs, water-quality measurements (including tritium), water-level measurements, and slug test data. The well penetrated 384.05 m (1,260 ft) of Quaternary alluvium, 541.93 m (1,778 ft) of Tertiary Volcanics (Tv) rocks, and 127.71 m (419 ft) of Paleozoic carbonates. The stratigraphy and lithology were generally as expected. However, several of the stratigraphic units were significantly thicker then predicted—principally, the Tunnel formation (Tn), which had been predicted to be 30 m (100 ft) thick; the actual thickness of this unit was 268.22 m (880 ft). Fluid depths were measured in the borehole during drilling as follows: (1) in the piezometer (p1) at 552.15 m (1,811.53 ft) bgs and (2) in the main casing (m1) at 551.69 m (1,810.01 ft) bgs. As expected, field measurements for tritium were above the Safe Drinking Water Act limit (20,000 picocuries per liter) for a portion of the Tertiary volcanic section near the water table. Tritium concentrations were at or near the field detection limit in the Lower carbonate aquifer (LCA) while drilling. During drilling, a sample was collected while circulating in the LCA. The sample was submitted for off-site laboratory analysis. The sample results indicated low but measurable tritium concentrations. All Fluid Management Plan requirements were met during drilling activities.« less

Infrared Spectroscopy for Rapid Characterization of Drill Core and Cutting Mineralogy

NASA Astrophysics Data System (ADS)

Calvin, W. M.; Kratt, C.; Kruse, F. A.

2009-12-01

Water geochemistry can vary with depth and location within a geothermal reservoir, owing to natural factors such as changing rock type, gas content, fluid source and temperature. The interaction of these variable fluids with the host rock will cause well known changes in alteration mineral assemblages that are commonly factored into the exploration of hydrothermal systems for economic metals, but are less utilized with regard to mapping borehole geology for geothermal energy production. Chemistry of geothermal fluids and rock alteration products can impact production factors such as pipeline corrosion and scaling and early studies explored the use of both silica and chlorites as geothermometers. Infrared spectroscopy is particularly good at identifying a wide variety of alteration minerals, especially in discrimination among clay minerals, with no sample preparation. The technique has been extensively used in the remote identification of materials, but is not commonly used on drill core or chips. We have performed several promising pilot studies that suggest the power of the technique to sample continuously and provide mineral logs akin to geophysical ones. We have surveyed a variety of samples, including drill chip boards, boxed core, and drill cuttings from envelopes, sample bottles and chip trays. This work has demonstrated that core and drill chips can be rapidly surveyed, acquiring spectra every few to tens of cm of section, or the vertical resolution of the chip tray (typically 10 feet). Depending on the sample type we can acquire spectral data over thousands of feet depth at high vertical resolution in a fraction of the time that is needed for traditional analytical methods such as XRD or TEM with better accuracy than traditional geologic drill or chip logging that uses visual inspection alone. We have successfully identified layered silicates such as illite, kaolinite, montmorillonite chlorite and prehnite, zeolites, opal, calcite, jarosite and iron oxides and hydroxides in geothermal drill samples. We are currently developing automated analysis techniques to convert this detailed spectral logging data into high-vertical-resolution mineral depth profiles that can be linked to lithology, stratigraphy, fracture zones and potential for geothermal production. Also in development are metrics that would link mapped mineralogy to known geothermometers such as Na-K, Mg depletion, discrimination among illite, montmorillonite, and beidellite, and kaolinite crystallinity. Identification of amorphous and crystalline silica components (chalcedony, crystobalite and quartz) can also constrain silica geothermometry. The degree of alteration and some mineral types have been shown to be a proxy for host rock permeability, natural circulation, and the potential for reservoir sealing. Analysis of alteration intensity is also under way. We will present a synthesis of results to date.

SPI Conformance Gel Applications in Geothermal Zonal Isolation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Lyle

Zonal isolation in geothermal injection and producing wells is important while drilling the wells when highly fractured geothermal zones are encountered and there is a need to keep the fluids from interfering with the drilling operation. Department of Energy’s (DOE) Energy Efficiency and Renewable Energy (EERE) objectives are to advance technologies to make it more cost effective to develop, produce, and monitor geothermal reservoirs and produce geothermal energy. Thus, zonal isolation is critical to well cost, reservoir evaluation and operations. Traditional cementing off of the lost circulation or thief zones during drilling is often done to stem the drilling mudmore » losses. This is an expensive and generally unsuccessful technique losing the potential of the remaining fracture system. Selective placement of strong SPI gels into only the offending fractures can maintain and even improve operational efficiency and resource life. The SPI gel system is a unique silicate based gel system that offers a promising solution to thief zones and conformance problems with water and CO2 floods and potentially geothermal operations. This gel system remains a low viscosity fluid until an initiator (either internal such as an additive or external such as CO2) triggers gelation. This is a clear improvement over current mechanical methods of using packers, plugs, liners and cementing technologies that often severely damage the highly fractured area that is isolated. In the SPI gels, the initiator sets up the fluid into a water-like (not a precipitate) gel and when the isolated zone needs to be reopened, the SPI gel may be removed with an alkaline solution without formation damage occurring. In addition, the SPI gel in commercial quantities is expected to be less expensive than competing mechanical systems and has unique deep placement possibilities. This project seeks to improve upon the SPI gel integrity by modifying the various components to impart temperature stability for use in geothermal.« less

Microbial communities at the borehole observatory on the Costa Rica Rift flank (Ocean Drilling Program Hole 896A).

PubMed

Nigro, Lisa M; Harris, Kate; Orcutt, Beth N; Hyde, Andrew; Clayton-Luce, Samuel; Becker, Keir; Teske, Andreas

2012-01-01

The microbiology of subsurface, hydrothermally influenced basaltic crust flanking mid-ocean ridges has remained understudied, due to the difficulty in accessing the subsurface environment. The instrumented boreholes resulting from scientific ocean drilling offer access to samples of the formation fluids circulating through oceanic crust. We analyzed the phylogenetic diversity of bacterial communities of fluid and microbial mat samples collected in situ from the observatory at Ocean Drilling Program Hole 896A, drilled into ~6.5 million-year-old basaltic crust on the flank of the Costa Rica Rift in the equatorial Pacific Ocean. Bacterial 16S rRNA gene sequences recovered from borehole fluid and from a microbial mat coating the outer surface of the fluid port revealed both unique and shared phylotypes. The dominant bacterial clones from both samples were related to the autotrophic, sulfur-oxidizing genus Thiomicrospira. Both samples yielded diverse gamma- and alphaproteobacterial phylotypes, as well as members of the Bacteroidetes, Planctomycetes, and Verrucomicrobia. Analysis of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL and cbbM) from the sampling port mat and from the borehole fluid demonstrated autotrophic carbon assimilation potential for in situ microbial communities; most cbbL genes were related to those of the sulfur-oxidizing genera Thioalkalivibrio and Thiomicrospira, and cbbM genes were affiliated with uncultured phylotypes from hydrothermal vent plumes and marine sediments. Several 16S rRNA gene phylotypes from the 896A observatory grouped with phylotypes recovered from seawater-exposed basalts and sulfide deposits at inactive hydrothermal vents, but there is little overlap with hydrothermally influenced basaltic boreholes 1026B and U1301A on the Juan de Fuca Ridge flank, suggesting that site-specific characteristics of Hole 896A (i.e., seawater mixing into borehole fluids) affect the microbial community composition.

Reconstructing paleo-precipitation amounts using a terrestrial hydrologic model: Lake Titicaca and the Salar de Uyuni, Peru and Bolivia

NASA Astrophysics Data System (ADS)

Nunnery, J. A.; Baker, P. A.; Coe, M. T.; Fritz, S. C.

2010-12-01

The Peruvian/Bolivian Altiplano has provided many information-rich records bearing on the history of the South American summer monsoon (SASM), a large-scale circulation system that is responsible for much of the precipitation over the Amazon basin and the southern tropics and subtropics. Examples of these paleoclimate time series include long, drill core records from Lake Titicaca (extending back to ca. 400 Ka, Fritz et al., 2007), the long drill core record from Salar de Uyuni (> 250 Ka, Baker et al., 2001; Fritz et al., 2004), paleo-lake level records from the Salar de Uyuni (e.g. Bills et al., 2004; Placzek et al, 2006); drill core records from the Rio Desaguadero valley (Rigsby et al., 2003), and ice core records from Quelccaya, Illimani, and Sajama (Thompson et al., 2000; Ramirez et al., 2003). Several previous studies using energy and water balance models have been applied to these records in attempts to provide quantitative constraints on paleo-temperature and paleo-precipitation (e.g. Kessler, 1984; Hastenrath and Kutzbach, 1985; Cross et al, 2001; Rowe and Dunbar, 2004; Arnold, 2002; Blodgett et al., 1997). For example, Blodgett et al. concluded that high paleolake stands in the Bolivian Altiplano, dated at ca. 16,000 cal. Yr BP (Bills et al., 1994) required precipitation 20% higher than modern at temperatures 5°C colder than modern. However, their model did not take into account the major overflow from Lake Titicaca. Using the THMB hydrologic model, we show that overflow from Lake Titicaca is necessary to produce and sustain large lakes in the Salar de Uyuni basin. This hydrological connection (via the Rio Desaguadero) between the northern and southern Altiplano likely was only established about 60,000 years ago. Prior to that, there were no sustained, large and deep paleolakes on the southern Altiplano. Rather, drill core evidence indicates a very long sequence of shallow, hypersaline lakes and playas.

An investigation of anticyclonic circulation in the southern Gulf of Riga during the spring period

NASA Astrophysics Data System (ADS)

Soosaar, Edith; Maljutenko, Ilja; Raudsepp, Urmas; Elken, Jüri

2014-04-01

Previous studies of the gulf-type Region of Freshwater Influence (ROFI) have shown that circulation near the area of freshwater inflow sometimes becomes anticyclonic. Such a circulation is different from basic coastal ocean buoyancy-driven circulation where an anticyclonic bulge develops near the source and a coastal current is established along the right hand coast (in the northern hemisphere), resulting in the general cyclonic circulation. The spring (from March to June) circulation and spreading of river discharge water in the southern Gulf of Riga (GoR) in the Baltic Sea was analyzed based on the results of a 10-year simulation (1997-2006) using the General Estuarine Transport Model (GETM). Monthly mean currents in the upper layer of the GoR revealed a double gyre structure dominated either by an anticyclonic or cyclonic gyre in the near-head southeastern part and corresponding cyclonic/anticyclonic gyre in the near-mouth northwestern part of the gulf. Time series analysis of PCA and vorticity, calculated from velocity data and model sensitivity tests, showed that in spring the anticyclonic circulation in the upper layer of the southern GoR is driven primarily by the estuarine type density field. This anticyclonic circulation is enhanced by easterly winds but blocked or even reversed by westerly winds. The estuarine type density field is maintained by salt flux in the northwestern connection to the Baltic Proper and river discharge in the southern GoR.

An investigation of anticyclonic circulation in the southern Gulf of Riga during the spring period

NASA Astrophysics Data System (ADS)

Soosaar, Edith; Maljutenko, Ilja; Raudsepp, Urmas; Elken, Jüri

2015-04-01

Previous studies of the gulf-type Region of Freshwater Influence (ROFI) have shown that circulation near the area of freshwater inflow sometimes becomes anticyclonic. Such a circulation is different from basic coastal ocean buoyancy-driven circulation where an anticyclonic bulge develops near the source and a coastal current is established along the right hand coast (in the northern hemisphere), resulting in the general cyclonic circulation. The spring (from March to June) circulation and spreading of river discharge water in the southern Gulf of Riga (GoR) in the Baltic Sea was analyzed based on the results of a 10-year simulation (1997-2006) using the General Estuarine Transport Model (GETM). Monthly mean currents in the upper layer of the GoR revealed a double gyre structure dominated either by an anticyclonic or cyclonic gyre in the near-head southeastern part and corresponding cyclonic/anticyclonic gyre in the near-mouth northwestern part of the gulf. Time series analysis of PCA and vorticity, calculated from velocity data and model sensitivity tests, showed that in spring the anticyclonic circulation in the upper layer of the southern GoR is driven primarily by the estuarine type density field. This anticyclonic circulation is enhanced by easterly winds but blocked or even reversed by westerly winds. The estuarine type density field is maintained by salt flux in the northwestern connection to the Baltic Proper and river discharge in the southern GoR.

Reversed flow of Atlantic deep water during the Last Glacial Maximum.

PubMed

Negre, César; Zahn, Rainer; Thomas, Alexander L; Masqué, Pere; Henderson, Gideon M; Martínez-Méndez, Gema; Hall, Ian R; Mas, José L

2010-11-04

The meridional overturning circulation (MOC) of the Atlantic Ocean is considered to be one of the most important components of the climate system. This is because its warm surface currents, such as the Gulf Stream, redistribute huge amounts of energy from tropical to high latitudes and influence regional weather and climate patterns, whereas its lower limb ventilates the deep ocean and affects the storage of carbon in the abyss, away from the atmosphere. Despite its significance for future climate, the operation of the MOC under contrasting climates of the past remains controversial. Nutrient-based proxies and recent model simulations indicate that during the Last Glacial Maximum the convective activity in the North Atlantic Ocean was much weaker than at present. In contrast, rate-sensitive radiogenic (231)Pa/(230)Th isotope ratios from the North Atlantic have been interpreted to indicate only minor changes in MOC strength. Here we show that the basin-scale abyssal circulation of the Atlantic Ocean was probably reversed during the Last Glacial Maximum and was dominated by northward water flow from the Southern Ocean. These conclusions are based on new high-resolution data from the South Atlantic Ocean that establish the basin-scale north to south gradient in (231)Pa/(230)Th, and thus the direction of the deep ocean circulation. Our findings are consistent with nutrient-based proxies and argue that further analysis of (231)Pa/(230)Th outside the North Atlantic basin will enhance our understanding of past ocean circulation, provided that spatial gradients are carefully considered. This broader perspective suggests that the modern pattern of the Atlantic MOC-with a prominent southerly flow of deep waters originating in the North Atlantic-arose only during the Holocene epoch.

Serial detection of circulating tumour cells by reverse transcriptase-polymerase chain reaction assays is a marker for poor outcome in patients with malignant melanoma

PubMed Central

Palmieri, Giuseppe; Satriano, Sabrina MR; Budroni, Mario; Cossu, Antonio; Tanda, Francesco; Canzanella, Sergio; Caracò, Corrado; Simeone, Ester; Daponte, Antonio; Mozzillo, Nicola; Comella, Giuseppe; Castello, Giuseppe; Ascierto, Paolo A

2006-01-01

Background Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM). Methods One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up. Results Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (≥2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage. Conclusion Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease. PMID:17107608

Serial detection of circulating tumour cells by reverse transcriptase-polymerase chain reaction assays is a marker for poor outcome in patients with malignant melanoma.

PubMed

Palmieri, Giuseppe; Satriano, Sabrina M R; Budroni, Mario; Cossu, Antonio; Tanda, Francesco; Canzanella, Sergio; Caracò, Corrado; Simeone, Ester; Daponte, Antonio; Mozzillo, Nicola; Comella, Giuseppe; Castello, Giuseppe; Ascierto, Paolo A

2006-11-15

Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM). One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up. Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (> or =2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage. Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease.

On-Chip Microwave Quantum Hall Circulator

NASA Astrophysics Data System (ADS)

Mahoney, A. C.; Colless, J. I.; Pauka, S. J.; Hornibrook, J. M.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.; Doherty, A. C.; Reilly, D. J.

2017-01-01

Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1 /1000 th the wavelength by exploiting the chiral, "slow-light" response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330 μ m diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

Magnetostratigraphic, biostratigraphic, and stable isotope stratigraphy of an Upper Miocene drill core from the Salé Briqueterie (northwestern Morocco): A high-resolution chronology for the Messinian stage

NASA Astrophysics Data System (ADS)

Hodell, David A.; Benson, Richard H.; Kent, Dennis V.; Boersma, Anne; Rakic-El Bied, Kruna

1994-12-01

We report a high-resolution stable isotope, carbonate, magnetostratigraphic, and biostratigraphic record from a 175-m drill core from the Salé Briqueterie, which is part of the Bou Regreg section in northwestern Morocco. The Salé drill core spans the interval from paleomagnetic Chron C4n partim to C3r (earliest Gilbert), which represents the time leading up to and including the isolation and desiccation of the Mediterranean (i.e., the Messinian salinity crisis). During Chrons C3An and C3Ar (6.935 to 5.894 Ma) the isotope and carbonate signals display quasi-periodic variations with estimated periods of 40 and 100 kyr, respectively. We interpret the 40-kyr δ18O variations as reflecting changes in global ice volume caused by obliquity-induced changes (41 kyr) in solar insolation in polar regions. The 100-kyr carbonate variations probably represent long-term modulation of the amplitude of the precessional cycle (˜21 kyr), which is not resolved by our sampling frequency. The cyclic nature of the oxygen isotope signal permits us to extend the isotope nomenclature of Shackleton et al. (1994a) from stage TG24 in Chron C3r (earliest Gilbert) to stage C3Ar.δ18O.18 at the base of Chron C3Ar (6.935 Ma). A major change in paleoceanographic conditions is recorded across the Tortonian/Messinian boundary, which we correlate to Chron C3Bn at 7.04 Ma. Benthic foraminiferal δ18O values increased by an average of 0.4‰ in two steps at 7.17 Ma and 6.8 Ma and δ13C values decreased by 0.7-0.8‰ between 7.1 and 6.8 Ma, representing the late Miocene carbon shift. The first step in δ18O values coincides with an inferred reversal in deep water circulation through the Rifian Corridor, and the second correlates with the base of the Tripoli Formation and onset of "crisis conditions" in the Mediterranean. We suggest that the increase in δ18O values represents, at least in part, an increase in global ice volume that lowered sea level and contributed to the establishment of a negative water budget in the Mediterranean. Average δ18O values remained high throughout most of Chrons C3Ar and C3An, reaching maximum δ18O values during isotope stages TG20 and 22 in Chron C3r (earliest Gilbert). The glacio-eustatic falls associated with these events may have resulted in the complete isolation of the Mediterranean from the world ocean (Shackleton et al., 1994a). Following stage TG12 in the Salé record, there exists a trend toward progressively lower δ18O values that may represent a series of marine transgressions that eventually reflooded the Mediterranean and ended the Salinity Crisis.

Gold grade distribution within an epithermal quartz vein system, Kestanelik, NW Turkey: implications for gold exploration

NASA Astrophysics Data System (ADS)

Gulyuz, Nilay; Shipton, Zoe; Gulyuz, Erhan; Lord, Richard; Kaymakci, Nuretdin; Kuscu, İlkay

2017-04-01

Vein-hosted gold deposits contribute a large part to the global gold production. Discovery of these deposits mainly include drilling of hundreds of holes, collecting thousands of soil and rock samples and some geophysical surveys which are expensive and time consuming. Understanding the structures hosting the veins and the variations in gold concentrations within the veins is crucial to constrain a more economic exploration program. The main aim of this study is to investigate the gold grade distribution in the mineralized quartz veins of a well exposed epithermal gold deposit hosted by Paleozoic schist and Eocene quartz-feldspar-hornblende porphyry in Lapseki, NW Turkey. We have constructed 3D architecture of the vein surfaces by mapping their outcrop geometries using a highly sensitive Trimble GPS, collecting detailed field data, well-logs and geochemistry data from 396 drill holes (255 diamond cut and 141 reverse circulation holes). Modelling was performed in MOVE Structural Modelling and Analysis software granted by Midland Valley's Academic Software Initiative, and GIS application softwares Global Mapper and Esri-ArcGIS. We envisaged that while fluid entering the conduit ascents, a sudden thickness increase in the conduit would lead to a drop in the fluid pressure causing boiling (the most dominant gold precipitation mechanism) and associated gold precipitation. Regression analysis was performed between the orthogonal thickness values and gold grades of each vein, and statistical analyses were performed to see if the gold is concentrated at specific structural positions along dip. Gold grades in the alteration zones were compared to those in the adjacent veins to understand the degree of mineralization in alteration zones. A possible correlation was also examined between the host rock type and the gold grades in the veins. These studies indicated that gold grades are elevated in the adjacent alteration zones where high gold grades exist in the veins. Schist-hosted veins host the majority of gold mineralization (94.39%). While there is almost no correlation between the true vein thickness and the gold grade, 77.65% of high gold grades are located where the veins bend along dip. These results suggest that multiple gold precipitation mechanisms may have been active and boiling mechanism responsible for gold precipitation along the structural pathways was more effective than possible fluid-rock interaction or throttling mechanisms which will precipitate gold at adjacent alteration zones around the pathways at Kestanelik. In addition, specific structural locations such as vein bends are favorable for gold precipitation. This study emphasizes that structural architecture of the veins is one of the key controls on the location of high gold grades. In addition, adding structural data collection and mapping specific structural locations such as bends to the exploration program could permit the key locations of high gold grade to be identified faster, and to focus further drilling and assays.

Microhole Drilling Tractor Technology Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Western Well Tool

2007-07-09

In an effort to increase the U.S. energy reserves and lower costs for finding and retrieving oil, the USDOE created a solicitation to encourage industry to focus on means to operate in small diameter well-Microhole. Partially in response to this solicitation and because Western Well Tool's (WWT) corporate objective to develop small diameter coiled tubing drilling tractor, WWT responded to and was awarded a contract to design, prototype, shop test, and field demonstrate a Microhole Drilling Tractor (MDT). The benefit to the oil industry and the US consumer from the project is that with the MDT's ability to facilitate Coiledmore » Tubing drilled wells to be 1000-3000 feet longer horizontally, US brown fields can be more efficiently exploited resulting in fewer wells, less environmental impact, greater and faster oil recovery, and lower drilling costs. Shortly after award of the contract, WWT was approached by a major oil company that strongly indicated that the specified size of a tractor of 3.0 inches diameter was inappropriate and that immediate applications for a 3.38-inch diameter tractor would substantially increase the usefulness of the tool to the oil industry. Based on this along with an understanding with the oil company to use the tractor in multiple field applications, WWT applied for and was granted a no-cost change-of-scope contract amendment to design, manufacture, assemble, shop test and field demonstrate a prototype a 3.38 inch diameter MDT. Utilizing existing WWT tractor technology and conforming to an industry developed specification for the tool, the Microhole Drilling Tractor was designed. Specific features of the MDT that increase it usefulness are: (1) Operation on differential pressure of the drilling fluid, (2) On-Off Capability, (3) Patented unique gripping elements (4) High strength and flexibility, (5) Compatibility to existing Coiled Tubing drilling equipment and operations. The ability to power the MDT with drilling fluid results in a highly efficient tool that both delivers high level of force for the pressure available and inherently increases downhole reliability because parts are less subject to contamination. The On-Off feature is essential to drilling to allow the Driller to turn off the tractor and pull back while circulating in cleanout runs that keep the hole clean of drilling debris. The gripping elements have wide contact surfaces to the formation to allow high loads without damage to the formation. As part of the development materials evaluations were conducted to verify compatibility with anticipated drilling and well bore fluids. Experiments demonstrated that the materials of the tractor are essentially undamaged by exposure to typical drilling fluids used for horizontal coiled tubing drilling. The design for the MDT was completed, qualified vendors identified, parts procured, received, inspected, and a prototype was assembled. As part of the assembly process, WWT prepared Manufacturing instructions (MI) that detail the assembly process and identify quality assurance inspection points. Subsequent to assembly, functional tests were performed. Functional tests consisted of placing the MDT on jack stands, connecting a high pressure source to the tractor, and verifying On-Off functions, walking motion, and operation over a range of pressures. Next, the Shop Demonstration Test was performed. An existing WWT test fixture was modified to accommodate operation of the 3.38 inch diameter MDT. The fixture simulated the tension applied to a tractor while walking (pulling) inside 4.0 inch diameter pipe. The MDT demonstrated: (1) On-off function, (2) Pulling forces proportional to available differential pressure up to 4000 lbs, (3) Walking speeds to 1100 ft/hour. A field Demonstration of the MDT was arranged with a major oil company operating in Alaska. A demonstration well with a Measured Depth of approximately 15,000 ft was selected; however because of problems with the well drilling was stopped before the planned MDT usage. Alternatively, functional and operational tests were run with the MDT inside 4.5 inch tubing at depths of 800-950 ft. The MDT successfully demonstrated On-Off capability, pulled with up to 1465 lbs force, and verified its capability to transmit torque though it from the Orienter. Forces generated by the tractor were limited due to insufficient differential pressure because of the unloaded downhole motor, which is not typical during drilling conditions. Additionally, the Coefficient of Friction between the MDT grippers and the tubing was much less than the anticipated COF of the sandstone formation. Despite these minor limitations, to summarize the MDT operated as expected. Minor modifications to the MDT are being incorporated to improve gripping capability of the tractor. Additional demonstration wells are being arranged to expand on the project's goals of delivering a fully operational utilitarian tool for use throughout the US to improve reserves.« less

Origin and nature of crystal reflections: Results from integrated seismic measurements at the KTB superdeep drilling site

NASA Astrophysics Data System (ADS)

Harjes, H.-P.; Bram, K.; Dürbaum, H.-J.; Gebrande, H.; Hirschmann, G.; Janik, M.; KlöCkner, M.; Lüschen, E.; Rabbel, W.; Simon, M.; Thomas, R.; Tormann, J.; Wenzel, F.

1997-08-01

For almost 10 years the KTB superdeep drilling project has offered an excellent field laboratory for adapting seismic techniques to crystalline environments and for testing new ideas for interpreting seismic reflections in terms of lithological or textural properties of metamorphic rock units. The seismic investigations culminated in a three-dimensional (3-D) reflection survey on a 19×19 km area with the drill site at its center. Interpretation of these data resulted in a detailed, structural model of the German Continental Deep Drilling Program (KTB) location with dominant, steep faults in the upper crust. The 3-D reflection survey was part of a suite of seismic experiments, ranging from wide-angle reflection and refraction profiles to standard vertical seismic profiles (VSP) and more sophisticated surface-to-borehole observations. It was predicted that the drill bit would meet the most prominent, steeply dipping, crustal reflector at a depth of about 6500-7000 m, and indeed, the borehole penetrated a major fault zone in the depth interval between 6850 and 7300 m. This reflector offered the rare opportunity to relate logging results, reflective properties, and geology to observed and modeled data. Post-Variscan thrusting caused cataclastic deformation, with partial, strong alterations within a steeply dipping reverse fault zone. This process generated impedance contrasts within the fault zone on a lateral scale large enough to cause seismic reflections. This was confirmed by borehole measurements along the whole 9.1 km deep KTB profile. The strongest, reflected signals originated from fluid-filled fractures and cataclastic fracture zones rather than from lithological boundaries (i.e., first-order discontinuities between different rock types) or from texture- and/or foliation-induced anisotropy. During the interpretation of seismic data at KTB several lessons were learned: Conventional processing of two-dimensional (2-D) reflection data from a presite survey showed predominantly subhorizontal layering in the upper crust with reflectivity striking in the Variscan direction. Drilling, however, revealed that all rock units are steeply dipping. This confirms that surface common depth point (CDP) seismics strongly enhances subhorizontal reflectivity and may thus produce a very misleading crustal image. Although this was shown for synthetic examples earlier, the KTB provides the experimental proof of how crucial this insight can be.

Serological Evidence for the Circulation of Rift Valley Fever Virus in Domestic Small Ruminants in Southern Gabon.

PubMed

Maganga, Gael Darren; Abessolo Ndong, Andre Lea; Mikala Okouyi, Clency Sylde; Makiala Mandanda, Sheila; N'Dilimabaka, Nadine; Pinto, Anais; Agossou, Ernest; Cossic, Brieuc; Akue, Jean-Paul; Leroy, Eric Maurice

2017-06-01

Rift Valley fever (RVF) is a zoonotic disease, which caused several epidemics in humans in many countries of Africa. Using an inhibition enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription PCR, and nested one-step reverse transcription PCR, we conducted a cross-sectional study in populations of sheep and goats from the Mongo County in 2014 to determine the circulation of the Rift Valley fever virus (RVFV) in small ruminants from this area. From a total of 201 small ruminants (95 sheep and 106 goats), the overall IgG seroprevalence against the RVFV was 6.47% (13/201). No RVFV RNA was detected in the animal plasmas. Logistic regression analysis showed that age, species, sex, and locality were not the significant risk factors. The findings of this study highlight the risk of RVF for domestic ruminants bred in this region and for the human rural population living in contact with these animals and they emphasize the need to develop adequate control measures to limit this threat.

Challenges of constructing salt cavern gas storage in China

NASA Astrophysics Data System (ADS)

Xia, Yan; Yuan, Guangjie; Ban, Fansheng; Zhuang, Xiaoqian; Li, Jingcui

2017-11-01

After more than ten years of research and engineering practice in salt cavern gas storage, the engineering technology of geology, drilling, leaching, completion, operation and monitoring system has been established. With the rapid growth of domestic consumption of natural gas, the requirement of underground gas storage is increasing. Because high-quality rock salt resources about 1000m depth are relatively scarce, the salt cavern gas storages will be built in deep rock salt. According to the current domestic conventional construction technical scheme, construction in deep salt formations will face many problems such as circulating pressure increasing, tubing blockage, deformation failure, higher completion risk and so on, caused by depth and the complex geological conditions. Considering these difficulties, the differences between current technical scheme and the construction scheme of twin well and big hole are analyzed, and the results show that the technical scheme of twin well and big hole have obvious advantages in reducing the circulating pressure loss, tubing blockage and failure risk, and they can be the alternative schemes to solve the technical difficulties of constructing salt cavern gas storages in the deep rock salt.

Anticoagulation management associated with extracorporeal circulation.

PubMed

Sniecinski, Roman M; Levy, Jerrold H

2015-06-01

The use of extracorporeal circulation requires anticoagulation to maintain blood fluidity throughout the circuit, and to prevent thrombotic complications. Additionally, adequate suppression of hemostatic activation avoids the unnecessary consumption of coagulation factors caused by the contact of blood with foreign surfaces. Cardiopulmonary bypass represents the greatest challenge in this regard, necessitating profound levels of anticoagulation during its conduct, but also quick, efficient reversal of this state once the surgical procedure is completed. Although extracorporeal circulation has been around for more than half a century, many questions remain regarding how to best achieve anticoagulation for it. Although unfractionated heparin is the predominant agent used for cardiopulmonary bypass, the amount required and how best to monitor its effects are still unresolved. This review discusses the use of heparin, novel anticoagulants, and the monitoring of anticoagulation during the conduct of cardiopulmonary bypass. Copyright © 2015 Elsevier Ltd. All rights reserved.

Moral maps and medical imaginaries: clinical tourism at Malawi's College of Medicine.

PubMed

Wendland, Claire L

2012-01-01

At an understaffed and underresourced urban African training hospital, Malawian medical students learn to be doctors while foreign medical students, visiting Malawi as clinical tourists on short-term electives, learn about “global health.” Scientific ideas circulate fast there; clinical tourists circulate readily from outside to Malawi but not the reverse; medical technologies circulate slowly, erratically, and sometimes not at all. Medicine's uneven globalization is on full display. I extend scholarship on moral imaginations and medical imaginaries to propose that students map these wards variously as places in which—or from which—they seek a better medicine. Clinical tourists, enacting their own moral maps, also become representatives of medicine “out there”: points on the maps of others. Ethnographic data show that for Malawians, clinical tourists are colleagues, foils against whom they construct ideas about a superior and distinctly Malawian medicine and visions of possible alternative futures for themselves.

Cloud patterns lee of Hawaii Island: A synthesis of satellite observations and numerical simulation

NASA Astrophysics Data System (ADS)

Yang, Yang; Xie, Shang-Ping; Hafner, Jan

2008-08-01

Standing well above the trade wind inversion, Hawaii Island (maximum elevation ˜4.2 km) splits the northeast trade winds and induces a westerly reverse flow in the wake. Satellite observations and regional model simulations are used to investigate circulation effects on lee cloud formation during summer. Over the island, the cloud distribution is consistent with orographic-induced vertical motions. Over the lee ocean, our analysis reveals a cloud band that extends southwestward over a few tens of kilometers from the southwest coast of the island. This southwest lee cloud band is most pronounced in the afternoon, anchored by strong convergence and maintained by in situ cloud production in the upward motion. Such an offshore cloud band is not found off the northwest coast, an asymmetry possibly due to the Coriolis effect on the orographic flow. Off the Kona coast, the dynamically induced westerly reverse flow keeps the wake cool and nearly free of clouds during the day. Along the Kona coast, clouds are blown offshore from the island by the easterly trades in the afternoon in a layer above the reverse flow. Deprived of in situ production, these afternoon Kona coast clouds dissipate rapidly offshore. At night, the offshore land/valley breezes converge onto the onshore reverse flow, and a cloud deck forms on and off the Kona coast, bringing nighttime rain as observed at land stations. To illustrate the circulation effect, lee cloud formation is compared between tall Hawaii and short Kauai/Oahu Islands, which feature the flow-around and flow-over regimes, respectively. Effects of trade wind strength on the leeside cloudiness are also studied.

Long-term reversal of diabetes in non-obese diabetic mice by liver-directed gene therapy.

PubMed

Ren, Binhai; O'Brien, Bronwyn A; Byrne, Michelle R; Ch'ng, Edwin; Gatt, Prudence N; Swan, M Anne; Nassif, Najah T; Wei, Ming Q; Gijsbers, Rik; Debyser, Zeger; Simpson, Ann M

2013-01-01

Type 1 diabetes (T1D) results from an autoimmune attack against the insulin-producing β-cells of the pancreas. The present study aimed to reverse T1D by gene therapy. We used a novel surgical technique, which involves isolating the liver from the circulation before the delivery of a lentiviral vector carrying furin-cleavable human insulin (INS-FUR) or empty vector to the livers of diabetic non-obese diabetic mice (NOD). This was compared with the direct injection of the vector into the portal circulation. Mice were monitored for body weight and blood glucose. Intravenous glucose tolerance tests were performed. Expression of insulin and pancreatic transcription factors was determined by the reverse transcriptase-polymerase chain reaction and immunohistochemistry and immunoelectron microscopy was used to localise insulin. Using the novel surgical technique, we achieved long-term transduction (42% efficiency) of hepatocytes, restored normoglycaemia for 150 days (experimental endpoint) and re-established normal glucose tolerance. We showed the expression of β-cell transcription factors, murine insulin, glucagon and somatostatin, and hepatic storage of insulin in granules. The expression of hepatic markers, C/EBP-β, G6PC, AAT and GLUI was down-regulated in INS-FUR-treated livers. Liver function tests remained normal, with no evidence of intrahepatic inflammation or autoimmune destruction of the insulin-secreting liver tissue. By comparison, direct injection of INS-FUR reduced blood glucose levels, and no pancreatic transdifferentiation or normal glucose tolerance was observed. This gene therapy protocol has, for the first time, permanently reversed T1D with normal glucose tolerance in NOD mice and, as such, represents a novel therapeutic strategy for the treatment of T1D. Copyright © 2013 John Wiley & Sons, Ltd.

A world-class target for ICDP drilling at Lake Nam Co, Tibetan Plateau, China: progresses and perspectives

NASA Astrophysics Data System (ADS)

Zhu, L.; Wang, J.; Daut, G.; Spiess, V.; Haberzettl, T.; Schulze, N.; Ju, J.; Lü, X.; Bergmann, F.; Haberkern, J.; Schwalb, A.; Mäusbacher, R.

2017-12-01

Lake Nam Co (ca. 2000 km2, 4718 m a.s.l., maximum depth: 100 m) is located at the interaction zone of the Westerlies and the Indian monsoon on the central Tibetan Plateau. It was part of a mega-lake during Marine Isotope Stage (MIS) 3 before the Last Glacial Maximum. A long term sedimentary record from Nam Co could therefore provide an excellent paleo-environmental sequence for regional and global comparative studies. This will to deepen our understanding of large scale atmospheric circulation shifts and the environmental links between the Tibetan Plateau at low latitudes and the North Atlantic region at high latitudes. A Nam Co deep drilling will fill the gap in two large scale ICDP/IODP drilling transects (N-S: Lake Baikal, Lake Qinghai, Bay of Bengal; W-E: Lake Van, Lake Issyk-Kul, South China Sea, Lake Towuti), which will show the great significance of monsoon dynamics on a long-term scale. Multidisciplinary researches have been conducted since 2005 by a Sino-German cooperative team. The progresses during the last decade are: 1) Detailed bathymetric surveying, including a shallow sediment profiler investigation (Innomar SES 2000 light, ca. 30 m sediment penetration); 2) Paleo-environmental reconstructions covering the past 24 ka; 3) Modern sediment distribution covering the entire lake; 4) Monitoring including water temperature profiles, sediment traps, seasonal airborne pollen collection; 5) Deep seismic survey penetrating up to 800 meters of lake sediments. Based on sediment rates from reference core NC08/01, seismic results show that an age of 500 ka may be reached at 500 m, and >1 Ma at the observed base. Faulting can be clearly detected in the seismic profiles, especially from MIS 5 to early Holocene, and shows the characteristics of normal faults or strike-slip faults. Both rotation of the layers and the close spacing, along with negative and positive offsets of the faults make a transtensional origin of the basin likely. An ICDP workshop proposal was approved this year (ID: ICDP-2017/10, http://www.icdp-online.org/projects/world/asia/lake-nam-co/). The workshop will likely be held in May 2018 in Beijing, where future scientific objectives, potential coring locations and logistics of a drilling campaign will be intensively discussed to ensure a successful drilling campaign in the near future.

Action of the Metalloproteinases in Gonadal Remodeling during Sex Reversal in the Sequential Hermaphroditism of the Teleostei Fish Synbranchus marmoratus (Synbranchiformes: Synbranchidae)

PubMed Central

Mazzoni, Talita Sarah; Lo Nostro, Fabiana Laura; Antoneli, Fernanda Natália; Quagio-Grassiotto, Irani

2018-01-01

Teleostei present great plasticity regarding sex change. During sex reversal, the whole gonad including the germinal epithelium undergoes significant changes, remodeling, and neoformation. However, there is no information on the changes that occur within the interstitial compartment. Considering the lack of information, especially on the role played by metalloproteinases (MMPs) in fish gonadal remodeling, the aim of this study was to evaluate the action of MMPs on gonads of sex reversed females of Synbranchus marmoratus, a fresh water protogynic diandric fish. Gonads were processed for light microscopy and blood samples were used for the determination of plasma sex steroid levels. During sex reversal, degeneration of the ovaries occurred and were gradually replaced by the germinal tissue of the male. The action of the MMPs induces significant changes in the interstitial compartment, allowing the reorganization of germinal epithelium. Leydig cells also showed an important role in female to male reversion. The gonadal transition coincides with changes in circulating sex steroid levels throughout sex reversion. The action of the MMPs, in the gonadal remodeling, especially on the basement membrane, is essential for the establishment of a new functional germinal epithelium. PMID:29695033

Tropical circulation and precipitation response to ozone depletion and recovery

NASA Astrophysics Data System (ADS)

Brönnimann, Stefan; Jacques-Coper, Martín; Rozanov, Eugene; Fischer, Andreas M.; Morgenstern, Olaf; Zeng, Guang; Akiyoshi, Hideharu; Yamashita, Yousuke

2017-06-01

Among the few well established changes in atmospheric circulation in recent decades are those caused by stratospheric ozone depletion. They include a strengthening and poleward contraction of the westerly atmospheric circulation over the Southern extratropics, i.e. a strengthening Southern Annular Mode (SAM), in austral spring and summer. Associated effects on extratropical temperature and precipitation and more recently subtropical precipitation have been documented and are understood in a zonal mean framework. We present zonally asymmetric effects of ozone depletion that reach into the tropics and affect atmospheric circulation and precipitation, including the South Pacific Convergence Zone (SPCZ), the most important rainband of the Southern Hemisphere. Using observation-based analyses and model simulations we show that over the 1961-1996 period, ozone depletion led to increased precipitation at the northern flank of the SPCZ and to decreased precipitation to the south. The effects originate from a flow pattern over the southwestern Pacific that extends equatorward and alters the propagation of synoptic waves and thus the position of the SPCZ. Model simulations suggest that anticipated stratospheric ozone recovery over the next decades will reverse these effects.

Neuroendocrine correlates of sex-role reversal in barred buttonquails

PubMed Central

2016-01-01

Sex differences in brain structure and behaviour are well documented among vertebrates. An excellent model exploring the neural mechanisms of sex differences in behaviour is represented by sex-role-reversed species. In the majority of bird species, males compete over access to mates and resources more strongly than do females. It is thought that the responsible brain regions are therefore more developed in males than in females. Because these behaviours and brain regions are activated by androgens, males usually have increased testosterone levels during breeding. Therefore, in species with sex-role reversal, certain areas of the female brain should be more developed or steroid hormone profiles should be sexually reversed. Here, I studied circulating hormone levels and gene expression of steroid hormone receptors and aromatase in a captive population of barred buttonquails (Turnix suscitator). While females performed courtship and agonistic behaviours, there was no evidence for sexually reversed hormone profiles. However, I found female-biased sex differences in gene expression of androgen receptors in several hypothalamic and limbic brain regions that were already in place at hatching. Such sex differences are not known from non-sex-role-reversed species. These data suggest that increased neural sensitivity to androgens could be involved in the mechanisms mediating sex-role-reversed behaviours. PMID:27881754

Decreased frequency and function of circulating plasmocytoid dendritic cells (pDC) in hepatitis B virus infected humans.

PubMed

Duan, Xue-Zhang; Wang, Min; Li, Han-Wei; Zhuang, Hui; Xu, Dongping; Wang, Fu-Sheng

2004-11-01

The Type 2 precursor plasmacytoid dendritic cells (pDC) represent the most important cell type in antiviral innate immunity. To understand the function of pDC during hepatitis B virus infection, the frequency and function of circulating pDC were analyzed by flow cytometric analysis, and IFN-alpha secretion of total PBMCs was determined by ELISA assay in 25 healthy subjects and 116 patients at various stages of chronic hepatitis B virus infection (CHB). The number of circulating pDC was found to be significantly lower in patients with CHB and associated liver cirrhosis (LC). The ability of PBMCs to secrete IFN-alpha also decreased significantly. There was a corresponding decrease of circulating NK cells and CD8+ T cells. We observed that lamuvidine antiviral therapy restored the number of circulating pDC and there was a reversal of pDC frequency with the control of HBV replication in chronic HBV patients, indicating these subjects are unlikely to be totally immunocompromised. The decrease of pDC was found to be related to nosocomial infections in LC patients. Our results suggest that CHB patients probably have a quantitative and qualitative impairment of circulating pDC or NK cells, which may be associated with HBV persistent infection as well as the nosocomial infections that arise in LC patients.

Testis cancer: the forgotten poster child.

PubMed

Raghavan, Derek

2014-07-15

In germ cell cancers, the unique reversibility of malignancy and the balance between somatic differentiation and dedifferentiation may be critical to late relapse that is dominated by non-germ cell elements. Targeting regulators of differentiation may provide a solution, and this may be elucidated via serial liquid biopsies (via circulating tumor cells). ©2014 American Association for Cancer Research.

Flow convergence caused by a salinity minimum in a tidal channel

USGS Publications Warehouse

Warner, John C.; Schoellhamer, David H.; Burau, Jon R.; Schladow, S. Geoffrey

2006-01-01

Residence times of dissolved substances and sedimentation rates in tidal channels are affected by residual (tidally averaged) circulation patterns. One influence on these circulation patterns is the longitudinal density gradient. In most estuaries the longitudinal density gradient typically maintains a constant direction. However, a junction of tidal channels can create a local reversal (change in sign) of the density gradient. This can occur due to a difference in the phase of tidal currents in each channel. In San Francisco Bay, the phasing of the currents at the junction of Mare Island Strait and Carquinez Strait produces a local salinity minimum in Mare Island Strait. At the location of a local salinity minimum the longitudinal density gradient reverses direction. This paper presents four numerical models that were used to investigate the circulation caused by the salinity minimum: (1) A simple one-dimensional (1D) finite difference model demonstrates that a local salinity minimum is advected into Mare Island Strait from the junction with Carquinez Strait during flood tide. (2) A three-dimensional (3D) hydrodynamic finite element model is used to compute the tidally averaged circulation in a channel that contains a salinity minimum (a change in the sign of the longitudinal density gradient) and compares that to a channel that contains a longitudinal density gradient in a constant direction. The tidally averaged circulation produced by the salinity minimum is characterized by converging flow at the bed and diverging flow at the surface, whereas the circulation produced by the constant direction gradient is characterized by converging flow at the bed and downstream surface currents. These velocity fields are used to drive both a particle tracking and a sediment transport model. (3) A particle tracking model demonstrates a 30 percent increase in the residence time of neutrally buoyant particles transported through the salinity minimum, as compared to transport through a constant direction density gradient. (4) A sediment transport model demonstrates increased deposition at the near-bed null point of the salinity minimum, as compared to the constant direction gradient null point. These results are corroborated by historically noted large sedimentation rates and a local maximum of selenium accumulation in clams at the null point in Mare Island Strait.

Wind reversals in turbulent Rayleigh-Bénard convection.

PubMed

Araujo, Francisco Fontenele; Grossmann, Siegfried; Lohse, Detlef

2005-08-19

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-Bénard convection is theoretically analyzed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range 10(-2) < or = Pr < or = 10(3) and 10(7) < or = Ra < or = 10(12), the model has the following features: (i) chaotic reversals may be exhibited at Ra > or = 10(7); (ii) the Reynolds number based on the root mean square velocity scales as Re(rms) approximately Ra([0.41...0.47]) (depending on Pr), and as Re(rms) approximately Pr(-[0.66...0.76]) (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law omega/(nu L(-2)) approximately Pr(-(0.64 +/- 0.01))Ra(0.44 +/- 0.01). The phase diagram of the model is sketched, and the observed transitions are discussed.

Reversibly crosslinked nanocarriers for on-demand drug delivery in cancer treatment

PubMed Central

Shao, Yu; Huang, Wenzhe; Shi, Changying; Atkinson, Sean T; Luo, Juntao

2013-01-01

Polymer micelles have proven to be one of the most versatile nanocarriers for anticancer drug delivery. However, the in vitro and in vivo stability of micelles remains a challenge due to the dynamic nature of these self-assembled systems, which leads to premature drug release and nonspecific biodistribution in vivo. Recently, reversibly crosslinked micelles have been developed to provide solutions to stabilize nanocarriers in blood circulation. Increased stability allows nanoparticles to accumulate at tumor sites efficiently via passive and/or active tumor targeting, while cleavage of the micelle crosslinkages, through internal or external stimuli, facilitates on-demand drug release. In this review, various crosslinking chemistries as well as the choices for reversible linkages in these nanocarriers will be introduced. Then, the development of reversibly crosslinked micelles for on-demand drug release in response to single or dual stimuli in the tumor microenvironment is discussed, for example, acidic pH, reducing microenvironment, enzymatic microenvironment, photoirradiation and the administration of competitive reagents postmicelle delivery. PMID:23323559

Abrupt climate change and transient climates during the Paleogene: a marine perspective.

PubMed

Zachos, J C; Lohmann, K C; Walker, J C; Wise, S W

1993-03-01

Detailed investigations of high latitude sequences recently collected by the Ocean Drilling Program (ODP) indicate that periods of rapid climate change often culminated in brief transient climates, with more extreme conditions than subsequent long term climates. Two examples of such events have been identified in the Paleogene; the first in latest Paleocene time in the middle of a warming trend that began several million years earlier: the second in earliest Oligocene time near the end of a Middle Eocene to Late Oligocene global cooling trend. Superimposed on the earlier event was a sudden and extreme warming of both high latitude sea surface and deep ocean waters. Imbedded in the latter transition was an abrupt decline in high latitude temperatures and the brief appearance of a full size continental ice-sheet on Antarctica. In both cases the climate extremes were not stable, lasting for less than a few hundred thousand years, indicating a temporary or transient climate state. Geochemical and sedimentological evidence suggest that both Paleogene climate events were accompanied by reorganizations in ocean circulation, and major perturbations in marine productivity and the global carbon cycle. The Paleocene-Eocene thermal maximum was marked by reduced oceanic turnover and decreases in global delta 13C and in marine productivity, while the Early Oligocene glacial maximum was accompanied by intensification of deep ocean circulation and elevated delta 13C and productivity. It has been suggested that sudden changes in climate and/or ocean circulation might occur as a result of gradual forcing as certain physical thresholds are exceeded. We investigate the possibility that sudden reorganizations in ocean and/or atmosphere circulation during these abrupt transitions generated short-term positive feedbacks that briefly sustained these transient climatic states.

Abrupt climate change and transient climates during the Paleogene: a marine perspective

NASA Technical Reports Server (NTRS)

Zachos, J. C.; Lohmann, K. C.; Walker, J. C.; Wise, S. W.

1993-01-01

Detailed investigations of high latitude sequences recently collected by the Ocean Drilling Program (ODP) indicate that periods of rapid climate change often culminated in brief transient climates, with more extreme conditions than subsequent long term climates. Two examples of such events have been identified in the Paleogene; the first in latest Paleocene time in the middle of a warming trend that began several million years earlier: the second in earliest Oligocene time near the end of a Middle Eocene to Late Oligocene global cooling trend. Superimposed on the earlier event was a sudden and extreme warming of both high latitude sea surface and deep ocean waters. Imbedded in the latter transition was an abrupt decline in high latitude temperatures and the brief appearance of a full size continental ice-sheet on Antarctica. In both cases the climate extremes were not stable, lasting for less than a few hundred thousand years, indicating a temporary or transient climate state. Geochemical and sedimentological evidence suggest that both Paleogene climate events were accompanied by reorganizations in ocean circulation, and major perturbations in marine productivity and the global carbon cycle. The Paleocene-Eocene thermal maximum was marked by reduced oceanic turnover and decreases in global delta 13C and in marine productivity, while the Early Oligocene glacial maximum was accompanied by intensification of deep ocean circulation and elevated delta 13C and productivity. It has been suggested that sudden changes in climate and/or ocean circulation might occur as a result of gradual forcing as certain physical thresholds are exceeded. We investigate the possibility that sudden reorganizations in ocean and/or atmosphere circulation during these abrupt transitions generated short-term positive feedbacks that briefly sustained these transient climatic states.

Changing surface water conditions for the last 500 ka in the Southeast Atlantic: Implications for variable influences of Agulhas leakage and Benguela upwelling

NASA Astrophysics Data System (ADS)

Petrick, Benjamin F.; McClymont, Erin L.; Marret, Fabienne; van der Meer, Marcel T. J.

2015-09-01

The Southeast Atlantic Ocean is an important component of global ocean circulation, as it includes heat and salt transfer into the Atlantic through the Agulhas leakage as well as the highly productive Benguela upwelling system. Here we reconstruct sea surface temperatures (SSTs) from Ocean Drilling Program (ODP) Site 1087 in the Southeast Atlantic to investigate surface ocean circulation patterns during the late Pleistocene (0-500 ka). The UK'37 index and dinoflagellate cyst assemblages are used to reconstruct SSTs, δDalkenone is used to reconstruct changes in sea surface salinity, and mass accumulation rates of alkenones and chlorine pigments are quantified to detect changing marine export productivity. The greatest amplitude of SST warming precedes decreases in benthic δ18O and therefore occurs early in the transition from glacials to interglacials. The δDalkenone, as a salinity indicator, increases before SSTs, suggesting that the pattern of Agulhas leakage is more complex than suggested by SST proxies. Marine isotope stage (MIS) 10 shows an anomalous pattern: it is marked by a pronounced increase in chlorine concentration, which may be related to enhanced/expanded Benguela upwelling reaching the core site. We find no evidence of an absence of Agulhas leakage throughout the record, suggesting that there is no Agulhas cutoff even during MIS 10. Finally, the ODP Site 1087 record shows an increasing strength of Agulhas leakage towards the present day, which may have impacted the intensity of the Atlantic meridional overturning circulation. As a result, the new analyses from ODP Site 1087 demonstrate a complex interaction between influences of the Benguela upwelling and the Agulhas leakage through the late Pleistocene, which are inferred here to reflect changing circulation patterns in the Southern Ocean and in the atmosphere.

Percolation of diagenetic fluids in the Archaean basement of the Franceville basin

NASA Astrophysics Data System (ADS)

Mouélé, Idalina Moubiya; Dudoignon, Patrick; Albani, Abderrazak El; Cuney, Michel; Boiron, Marie-Christine; Gauthier-Lafaye, François

2014-01-01

The Palaeoproterozoic Franceville basin, Gabon, is mainly known for its high-grade uranium deposits, which are the only ones known to act as natural nuclear fission reactors. Previous work in the Kiéné region investigated the nature of the fluids responsible for these natural nuclear reactors. The present work focuses on the top of the Archaean granitic basement, specifically, to identify and date the successive alteration events that affected this basement just below the unconformity separating it from the Palaeoproterozoic basin. Core from four drill holes crosscutting the basin-basement unconformity have been studied. Dating is based on U-Pb isotopic analyses performed on monazite. The origin of fluids is discussed from the study of fluid inclusion planes (FIP) in quartz from basement granitoids. From the deepest part of the drill holes to the unconformable boundary with the basin, propylitic alteration assemblages are progressively replaced by illite and locally by a phengite + Fe chlorite ± Fe oxide assemblage. Illitic alteration is particularly strong along the sediment-granitoid contact and is associated with quartz dissolution. It was followed by calcite and anhydrite precipitation as fracture fillings. U-Pb isotopic dating outlines three successive events: a 3.0-2.9-Ga primary magmatic event, a 2.6-Ga propylitic alteration and a late 1.9-Ga diagenetic event. Fluid inclusion microthermometry suggests the circulation of three types of fluids: (1) a Na-Ca-rich diagenetic brine, (2) a moderately saline (diagenetic + meteoric) fluid, and (3) a low-salinity fluid of probable meteoric origin. These fluids are similar to those previously identified within the overlying sedimentary rocks of the Franceville basin. Overall, the data collected in this study show that the Proterozoic-Archaean unconformity has operated as a major flow corridor for fluids circulation, around 1.9 Ga. highly saline diagenetic brines; hydrocarbon-rich fluids derived from organic matter-rich formations; a low-salinity fluid likely of meteoric origin migrating through the granitic basement; mineralizing fluids resulting from the mixing of fluids 1 and 3; high-temperature fluids resulting from the natural nuclear reactor environment (Mathieu et al., 2000). The present paper attempts to characterize the succession of alteration events that have affected the top of the basement below the Palaeoproterozoic sediment unconformity. Are these alterations related to early post-magmatic to hydrothermal events, to palaeoweathering, or to late infiltration of diagenetic brines from the overlying basin? Our study, carried out on drill core samples from Kiéné, is supported by petrographic investigation, new fluid inclusion data and U-Pb geochronology on monazite.

Dealing With Shallow-Water Flow in the Deepwater Gulf of Mexico

NASA Astrophysics Data System (ADS)

Ostermeier, R.

2006-05-01

Some of the Shell experience in dealing with the shallow-water flow problem in the Deepwater Gulf of Mexico (GOM) will be presented. The nature of the problem, including areal extent and over-pressuring mechanisms, will be discussed. Methods for sand prediction and shallow sediment and flow characterization will be reviewed. These include seismic techniques, the use of geo-technical wells, regional trends, and various MWD methods. Some examples of flow incidents with pertinent drilling issues, including well failures and abandonment, will be described. To address the shallow-water flow problem, Shell created a multi-disciplinary team of specialists in geology, geophysics, petrophysics, drilling, and civil engineering. The team developed several methodologies to deal with various aspects of the problem. These include regional trends and data bases, shallow seismic interpretation and sand prediction, well site and casing point selection, geo-technical well design and data interpretation, logging program design and interpretation, cementing design and fluids formulation, methods for remediation and mitigation of lost circulation, and so on. Shell's extensive Deepwater GOM drilling experience has lead to new understanding of the problem. Examples include delineation of trends in shallow water flow occurrence and severity, trends and departures in PP/FG, rock properties pertaining to seismic identification of sands, and so on. New knowledge has also been acquired through the use of geo-technical wells. One example is the observed rapid onset and growth of over-pressures below the mudline. Total trouble costs due to shallow water flow for all GOM operators almost certainly runs into the several hundred million dollars. Though the problem remains a concern, advances in our knowledge and understanding make it a problem that is manageable and not the "show stopper" once feared.

High-quality heat flow determination from the crystalline basement of the south-east margin of North China Craton

NASA Astrophysics Data System (ADS)

Jiang, Guangzheng; Tang, Xiaoyin; Rao, Song; Gao, Peng; Zhang, Linyou; Zhao, Ping; Hu, Shengbiao

2016-03-01

Very few of heat flow data have come from the crystalline basement in the North China Craton but rather from boreholes in the sedimentary cover of oil-gas basins. Explorations for hot dry rock (HDR) geothermal resources and porphyry gold deposits in eastern China offer now valuable opportunities to study the terrestrial heat flow in the crystalline basement. In this study, we obtained continuous temperature logs from two boreholes (the LZ borehole with a depth of 3471 m and the DR borehole with a depth of 2179 m) located in the south-east margin of the North China Craton. The boreholes have experienced long shut-in times (442 days and 261 days for the LZ borehole and DR borehole, respectively); thus, it can be expected that the temperature conditions have re-equilibrated after drilling and drill-mud circulation. Rock thermal conductivity and radiogenic heat production were measured for 68 crystalline rock samples from these two boreholes. The measured heat-flow density was determined to be 71.8 ± 2.3 mW m-2 (for the LZ borehole) and 91.5 ± 1.2 mW m-2 (for the DR borehole). The heat flow for the LZ borehole is close to the value of 75 mW m-2 determined in the Chinese Continental Scientific Drilling main hole (CCSD MH), both being in the Sulu-Dabie orogenic belt and thus able to verify each other. The value for the DR borehole is higher than the above two values, which supports former high heat-flow values determined in the Bohai Bay Basin.

A synthesis of Plio-Pleistocene leaf wax biomarker records of hydrological variation in East Africa and their relationship with hominin evolution

NASA Astrophysics Data System (ADS)

Lupien, R.; Russell, J. M.; Campisano, C. J.; Feibel, C. S.; Deino, A. L.; Kingston, J.; Potts, R.; Cohen, A. S.

2017-12-01

Climate change is thought to play a critical role in human evolution. However, the mechanisms behind this relationship are difficult to test due to a lack of long, high-quality paleoclimate records from hominin fossil locales. We improve the understanding of this relationship by examining Plio-Pleistocene lake sediment cores from East Africa that were drilled by the Hominin Sites and Paleolakes Drilling Project, an international effort to study the environment in which our hominin ancestors evolved and dispersed. We have analyzed organic geochemical signals of climate from drill cores from Ethiopia and Kenya spanning the Pliocene to recent time (from north to south: paleolake Hadar, Lake Turkana, Lake Baringo, and paleolake Koora). Specifically, we analyzed the hydrogen isotopic composition of terrestrial leaf waxes, which records changes in regional atmospheric circulation and hydrology. We reconstructed quantitative records of rainfall amount at each of the study sites, which host sediment spanning different geologic times and regions. By compiling these records, we test hominin evolutionary hypotheses as well as crucial questions about climate trend and variability. We find that there is a gradual or step-wise enrichment in δDwax, signifying a trend from a wet to dry climate, from the Pliocene to the Pleistocene, perhaps implying an influence of global temperature, ice sheet extent, and/or atmospheric greenhouse gas concentrations on East African climate. However, the shift is small relative to the amplitude of orbital-scale isotopic variations. The records indicate a strong influence of eccentricity-modulated orbital precession, and imply that local insolation effects are the likely cause of East African precipitation. Several of the intervals of high isotopic variability coincide with key hominin fossil or technological transitions, suggesting that climate variability plays a key role in hominin evolution.

Federal Geothermal Research Program Update, FY 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Renner, Joel Lawrence

2001-08-01

The Department of Energy's Geothermal Program serves two broad purposes: 1) to assist industry in overcoming near-term barriers by conducting cost-shared research and field verification that allows geothermal energy to compete in today's aggressive energy markets; and 2) to undertake fundamental research with potentially large economic payoffs. The four categories of work used to distinguish the research activities of the Geothermal Program during FY 2000 reflect the main components of real-world geothermal projects. These categories form the main sections of the project descriptions in this Research Update. Exploration Technology research focuses on developing instruments and techniques to discover hidden hydrothermalmore » systems and to explore the deep portions of known systems. Research in geophysical and geochemical methods is expected to yield increased knowledge of hidden geothermal systems. Reservoir Technology research combines laboratory and analytical investigations with equipment development and field testing to establish practical tools for resource development and management for both hydrothermal reservoirs and enhanced geothermal systems. Research in various reservoir analysis techniques is generating a wide range of information that facilitates development of improved reservoir management tools. Drilling Technology focuses on developing improved, economic drilling and completion technology for geothermal wells. Ongoing research to avert lost circulation episodes in geothermal drilling is yielding positive results. Conversion Technology research focuses on reducing costs and improving binary conversion cycle efficiency, to permit greater use of the more abundant moderate-temperature geothermal resource, and on the development of materials that will improve the operating characteristics of many types of geothermal energy equipment. Increased output and improved performance of binary cycles will result from investigations in heat cycle research.« less

Federal Geothermal Research Program Update Fiscal Year 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Renner, J.L.

2001-08-15

The Department of Energy's Geothermal Program serves two broad purposes: (1) to assist industry in overcoming near-term barriers by conducting cost-shared research and field verification that allows geothermal energy to compete in today's aggressive energy markets; and (2) to undertake fundamental research with potentially large economic payoffs. The four categories of work used to distinguish the research activities of the Geothermal Program during FY 2000 reflect the main components of real-world geothermal projects. These categories form the main sections of the project descriptions in this Research Update. Exploration Technology research focuses on developing instruments and techniques to discover hidden hydrothermalmore » systems and to explore the deep portions of known systems. Research in geophysical and geochemical methods is expected to yield increased knowledge of hidden geothermal systems. Reservoir Technology research combines laboratory and analytical investigations with equipment development and field testing to establish practical tools for resource development and management for both hydrothermal reservoirs and enhanced geothermal systems. Research in various reservoir analysis techniques is generating a wide range of information that facilitates development of improved reservoir management tools. Drilling Technology focuses on developing improved, economic drilling and completion technology for geothermal wells. Ongoing research to avert lost circulation episodes in geothermal drilling is yielding positive results. Conversion Technology research focuses on reducing costs and improving binary conversion cycle efficiency, to permit greater use of the more abundant moderate-temperature geothermal resource, and on the development of materials that will improve the operating characteristics of many types of geothermal energy equipment. Increased output and improved performance of binary cycles will result from investigations in heat cycle research.« less

Unveiling climate and ice-sheet history from drilling in high-latitude margins and future perspectives

NASA Astrophysics Data System (ADS)

Escutia Dotti, Carlota

2010-05-01

Polar ice is an important component of the climate system, affecting global sea level, ocean circulation and heat transport, marine productivity, and albedo. During the last decades drilling in the Arctic (IODP ACEX and Bering Expeditions) and in Antarctica (ODP Legs 178, 188, IODP Expedition 318 and ANDRILL) has revealed regional information about sea ice and ice sheets development and evolution. Integration of this data with numerical modeling provide an understanding of the early development of the ice sheets and their variability through the Cenozoic. Much of this work points to atmospheric CO2 and other greenhouse gases concentrations as important triggering mechanism driving the onset of glaciation and subsequent ice volume variability. With current increasing atmospheric greenhouse gases concentrations resulting in rapidly rising global temperatures, studies of polar climates become increasingly prominent on the research agenda. Despite of the relevance of the high-latitudes in the global climate systems, the short- and long-term history of the ice sheets and sea-ice and its relationships with paleoclimatic, paleoceanographic, and sea level changes is still poorly understood. A multinational, multiplatform scientific drilling strategy is being developed to recover key physical evidence from selected high-latitude areas. This strategy is aimed at addressing key knowledge gaps about the role of polar ice in climate change, targeting questions such as timing of events, rates of change, tipping points, regional variations, and northern vs. southern hemispheres (in phase or out-of-phase) variability. This data is critical to provide constrains to sea-ice and ice sheet models, which are the basis for forecasting the future of the cryosphere in a warming world.

Detection of circulating Bmi-1 mRNA in plasma and its potential diagnostic and prognostic value for uterine cervical cancer.

PubMed

Zhang, Xin; Wang, Chuanxin; Wang, Lili; Du, Lutao; Wang, Shun; Zheng, Guixi; Li, Wei; Zhuang, Xuewei; Zhang, Xuhua; Dong, Zhaogang

2012-07-01

Bmi-1 is overexpressed in uterine cervical cancer (UCC) and is found to be associated with adverse clinical characteristics and poor prognosis. However, little information is available on the status of circulating Bmi-1 mRNA in UCC. Because circulating cell-free nucleic acids have emerged as a novel class of markers for cancer detection, our research aims to address this question by detecting the circulating Bmi-1 mRNA and to assess its diagnostic and prognostic potential in UCC. Reverse transcription quantitative real-time PCR method was established to detect the circulating Bmi-1 mRNA in plasma of 109 patients with UCC, 138 patients with cervical intraepithelial neoplasia (CIN) and 80 healthy volunteers, and found that it was significantly increased in UCC compared with CINs and healthy controls (all at p < 0.001). Moreover, its high level was significantly correlated with advanced clinical stage (p < 0.001) and positive lymph nodes metastasis (p = 0.002). The area under the receiver operating characteristic curve (AUC) was 0.881, and the optimal cut-off value was 0.057, providing a sensitivity of 69.7% and a specificity of 95.9%. The AUC for circulating Bmi-1 mRNA showed higher diagnosis capability than that for SCC-Ag (p = 0.035) or CA125 (p < 0.001) currently utilized. Kaplan-Meier analysis demonstrated a correlation between increased circulating Bmi-1 mRNA level and reduced disease-free survival (DFS) (p = 0.001) and overall survival (OS) (p = 0.015). And, Cox analysis indicated that it was an independent prognostic factor for DFS and OS. We conclude that circulating Bmi-1 mRNA may be a potential noninvasive molecular marker for diagnosis and prognosis of UCC. Copyright © 2011 UICC.

Looking into a volcanic area: An overview on the 350 m scientific drilling at Colli Albani (Rome, Italy)

NASA Astrophysics Data System (ADS)

Mariucci, M. Teresa; Pierdominici, Simona; Pizzino, Luca; Marra, Fabrizio; Montone, Paola

2008-09-01

A 350 m deep borehole was drilled in the Colli Albani volcanic district (Central Italy) in order to: understand the shallow crust structure beneath the volcanic complex; characterize the rock physical properties especially through in-situ measurements and, afterward, laboratory experiments; assess the local present-day stress field; install a broad-band seismometer at depth. The borehole is located adjacent to the western rim of the Tuscolano-Artemisio caldera, where several phenomena of unrest recently occurred. In 1989-90 a seismic swarm affected this area and a related uplift was recognized. In addition, high gas concentrations (mainly CO 2 and H 2S), in aquifers and soils, caused illnesses and casualties among inhabitants and animals in the past. We describe the investigations carried out at the drill site and the results achieved from data analysis. Wire-line drilling produced a complete stratigraphic record of the Quaternary volcanic units down to the Plio-Pleistocene sedimentary sequence and geophysical logs allowed a characterization of the rock physical properties. From a tectonic point of view, data provided by Dipmeter and Borehole Televiewer were used for investigations on the recent and present-day stress field and the results are compared to those available in the literature. In the volcanic units we recognized two main fracture systems, SW and NW dipping. Several faults intersecting the borehole show planes with oblique striae, indicating a prevalent strike-slip component of the movement. Finally, borehole breakout analysis defined an active stress field with a ˜ E-W oriented minimum horizontal component. At the end of the drilling, a blow-out occurred, due to pressurized fluids trapped into the sandy unit drilled in the last few meters of the hole. Sampling these fluids gave an additional value to the borehole, providing information about the deep volcanic circulation and its possible connection to a deep-seated magma chamber. The main results show water with a Na-HCO 3 chemistry and the highest salinity ever recognised in the area (Electrical Conductivity = 10.12 mS/cm). Stable O and H isotopes reveal a meteoric origin of water and the absence of tritium points out a long residence time in the aquifer. Emitted gas is CO 2-dominated, with N 2 as second most important component. Helium isotopic composition of the gas allows us to estimate a magmatic component ranging in the interval 40-50%, one of the highest in the Colli Albani. Carbon isotopes of CO 2 (- 0.53‰ vs. PDB) suggest that it could derive partly from a magmatic source and partly by the thermal decarbonation of the carbonatic basement.

Microbial Community Structure of Subglacial Lake Whillans, West Antarctica

PubMed Central

Achberger, Amanda M.; Christner, Brent C.; Michaud, Alexander B.; Priscu, John C.; Skidmore, Mark L.; Vick-Majors, Trista J.; Adkins, W.

2016-01-01

Subglacial Lake Whillans (SLW) is located beneath ∼800 m of ice on the Whillans Ice Stream in West Antarctica and was sampled in January of 2013, providing the first opportunity to directly examine water and sediments from an Antarctic subglacial lake. To minimize the introduction of surface contaminants to SLW during its exploration, an access borehole was created using a microbiologically clean hot water drill designed to reduce the number and viability of microorganisms in the drilling water. Analysis of 16S rRNA genes (rDNA) amplified from samples of the drilling and borehole water allowed an evaluation of the efficacy of this approach and enabled a confident assessment of the SLW ecosystem inhabitants. Based on an analysis of 16S rDNA and rRNA (i.e., reverse-transcribed rRNA molecules) data, the SLW community was found to be bacterially dominated and compositionally distinct from the assemblages identified in the drill system. The abundance of bacteria (e.g., Candidatus Nitrotoga, Sideroxydans, Thiobacillus, and Albidiferax) and archaea (Candidatus Nitrosoarchaeum) related to chemolithoautotrophs was consistent with the oxidation of reduced iron, sulfur, and nitrogen compounds having important roles as pathways for primary production in this permanently dark ecosystem. Further, the prevalence of Methylobacter in surficial lake sediments combined with the detection of methanogenic taxa in the deepest sediment horizons analyzed (34–36 cm) supported the hypothesis that methane cycling occurs beneath the West Antarctic Ice Sheet. Large ratios of rRNA to rDNA were observed for several operational taxonomic units abundant in the water column and sediments (e.g., Albidiferax, Methylobacter, Candidatus Nitrotoga, Sideroxydans, and Smithella), suggesting a potentially active role for these taxa in the SLW ecosystem. Our findings are consistent with chemosynthetic microorganisms serving as the ecological foundation in this dark subsurface environment, providing new organic matter that sustains a microbial ecosystem beneath the West Antarctic Ice Sheet. PMID:27713727

Combined Application of Shallow Seismic Reflection and High-resolution Refraction Exploration Approach to Active Fault Survey, Central Orogenic Belt, China

NASA Astrophysics Data System (ADS)

Lin, S.; Luo, D.; Yanlin, F.; Li, Y.

2016-12-01

Shallow Seismic Reflection (SSR) is a major geophysical exploration method with its exploration depth range, high-resolution in urban active fault exploration. In this paper, we carried out (SSR) and High-resolution refraction (HRR) test in the Liangyun Basin to explore a buried fault. We used NZ distributed 64 channel seismic instrument, 60HZ high sensitivity detector, Geode multi-channel portable acquisition system and hammer source. We selected single side hammer hit multiple overlay, 48 channels received and 12 times of coverage. As there are some coincidence measuring lines of SSR and HRR, we chose multi chase and encounter observation system. Based on the satellite positioning, we arranged 11 survey lines in our study area with total length for 8132 meters. GEOGIGA seismic reflection data processing software was used to deal with the SSR data. After repeated tests from the aspects of single shot record compilation, interference wave pressing, static correction, velocity parameter extraction, dynamic correction, eventually got the shallow seismic reflection profile images. Meanwhile, we used Canadian technology company good refraction and tomographic imaging software to deal with HRR seismic data, which is based on nonlinear first arrival wave travel time tomography. Combined with drilling geological profiles, we explained 11 measured seismic profiles. Results show 18 obvious fault feature breakpoints, including 4 normal faults of south-west, 7 reverse faults of south-west, one normal fault of north-east and 6 reverse faults of north-east. Breakpoints buried depth is 15-18 meters, and the inferred fault distance is 3-12 meters. Comprehensive analysis shows that the fault property is reverse fault with northeast incline section, and fewer branch normal faults presenting southwest incline section. Since good corresponding relationship between the seismic interpretation results, drilling data and SEM results on the property, occurrence, broken length of the fault, we considered the Liangyun fault to be an active fault which has strong activity during the Neogene Pliocene and early Pleistocene, Middle Pleistocene period. The combined application of SSR and HRR can provide more parameters to explain the seismic results, and improve the accuracy of the interpretation.

Architecture of buried reverse fault zone in the sedimentary basin: A case study from the Hong-Che Fault Zone of the Junggar Basin

NASA Astrophysics Data System (ADS)

Liu, Yin; Wu, Kongyou; Wang, Xi; Liu, Bo; Guo, Jianxun; Du, Yannan

2017-12-01

It is widely accepted that the faults can act as the conduits or the barrier for oil and gas migration. Years of studies suggested that the internal architecture of a fault zone is complicated and composed of distinct components with different physical features, which can highly influence the migration of oil and gas along the fault. The field observation is the most useful methods of observing the fault zone architecture, however, in the petroleum exploration, what should be concerned is the buried faults in the sedimentary basin. Meanwhile, most of the studies put more attention on the strike-slip or normal faults, but the architecture of the reverse faults attracts less attention. In order to solve these questions, the Hong-Che Fault Zone in the northwest margin of the Junggar Basin, Xinjiang Province, is chosen for an example. Combining with the seismic data, well logs and drill core data, we put forward a comprehensive method to recognize the internal architectures of buried faults. High-precision seismic data reflect that the fault zone shows up as a disturbed seismic reflection belt. Four types of well logs, which are sensitive to the fractures, and a comprehensive discriminated parameter, named fault zone index are used in identifying the fault zone architecture. Drill core provides a direct way to identify different components of the fault zone, the fault core is composed of breccia, gouge, and serpentinized or foliated fault rocks and the damage zone develops multiphase of fractures, which are usually cemented. Based on the recognition results, we found that there is an obvious positive relationship between the width of the fault zone and the displacement, and the power-law relationship also exists between the width of the fault core and damage zone. The width of the damage zone in the hanging wall is not apparently larger than that in the footwall in the reverse fault, showing different characteristics with the normal fault. This study provides a comprehensive method in identifying the architecture of buried faults in the sedimentary basin and would be helpful in evaluating the fault sealing behavior.

Genome-wide sequencing and quantification of circulating microRNAs for dogs with congestive heart failure secondary to myxomatous mitral valve degeneration.

PubMed

Jung, SeungWoo; Bohan, Amy

2018-02-01

OBJECTIVE To characterize expression profiles of circulating microRNAs via genome-wide sequencing for dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve degeneration (MMVD). ANIMALS 9 healthy client-owned dogs and 8 age-matched client-owned dogs with CHF secondary to MMVD. PROCEDURES Blood samples were collected before administering cardiac medications for the management of CHF. Isolated microRNAs from plasma were classified into microRNA libraries and subjected to next-generation sequencing (NGS) for genome-wide sequencing analysis and quantification of circulating microRNAs. Quantitative reverse transcription PCR (qRT-PCR) assays were used to validate expression profiles of differentially expressed circulating microRNAs identified from NGS analysis of dogs with CHF. RESULTS 326 microRNAs were identified with NGS analysis. Hierarchical analysis revealed distinct expression patterns of circulating microRNAs between healthy dogs and dogs with CHF. Results of qRT-PCR assays confirmed upregulation of 4 microRNAs (miR-133, miR-1, miR-let-7e, and miR-125) and downregulation of 4 selected microRNAs (miR-30c, miR-128, miR-142, and miR-423). Results of qRT-PCR assays were highly correlated with NGS data and supported the specificity of circulating microRNA expression profiles in dogs with CHF secondary to MMVD. CONCLUSIONS AND CLINICAL RELEVANCE These results suggested that circulating microRNA expression patterns were unique and could serve as molecular biomarkers of CHF in dogs with MMVD.

Seismic Prediction While Drilling (SPWD): Seismic exploration ahead of the drill bit using phased array sources

NASA Astrophysics Data System (ADS)

Jaksch, Katrin; Giese, Rüdiger; Kopf, Matthias

2010-05-01

In the case of drilling for deep reservoirs previous exploration is indispensable. In recent years the focus shifted more on geological structures like small layers or hydrothermal fault systems. Beside 2D- or 3D-seismics from the surface and seismic measurements like Vertical Seismic Profile (VSP) or Seismic While Drilling (SWD) within a borehole these methods cannot always resolute this structures. The resolution is worsen the deeper and smaller the sought-after structures are. So, potential horizons like small layers in oil exploration or fault zones usable for geothermal energy production could be failed or not identified while drilling. The application of a device to explore the geology with a high resolution ahead of the drill bit in direction of drilling would be of high importance. Such a device would allow adjusting the drilling path according to the real geology and would minimize the risk of discovery and hence the costs for drilling. Within the project SPWD a device for seismic exploration ahead of the drill bit will be developed. This device should allow the seismic exploration to predict areas about 50 to 100 meters ahead of the drill bit with a resolution of one meter. At the GFZ a first prototype consisting of different units for seismic sources, receivers and data loggers has been designed and manufactured. As seismic sources four standard magnetostrictive actuators and as receivers four 3-component-geophones are used. Every unit, actuator or geophone, can be rotated in steps of 15° around the longitudinal axis of the prototype to test different measurement configurations. The SPWD prototype emits signal frequencies of about 500 up to 5000 Hz which are significant higher than in VSP and SWD. An increased radiation of seismic wave energy in the direction of the borehole axis allows the view in areas to be drilled. Therefore, every actuator must be controlled independently of each other regarding to amplitude and phase of the source signal to maximize the energy of the seismic source in order to reach a sufficient exploration range. The next step for focusing is to use the method of phased array. Dependent of the seismic wave velocities of the surrounding rock, the distance of the actuators to each other and the used frequencies the signal phases for each actuator can be determined. Since one year several measurements with the prototype have been realized under defined conditions at a test site in a mine. The test site consists of a rock block surrounded from three galleries with a dimension of about 100 by 200 meters. For testing the prototype two horizontal boreholes were drilled. They are directed to one of the gallery to get a strong reflector. The quality of the data of the borehole seismics in amplitude and frequency spectra show overall a good signal-to-noise ratio and correlate strongly with the fracture density along the borehole and are associated with a lower signal-to-noise ratio. Additionally, the geophones of the prototype show reflections from ahead and rearward in the seismic data. In particular, the reflections from the gallery ahead are used for the calibration of focusing. The direct seismic wave field indicates distinct compression and shear waves. The analysis of several seismic measurements with a focus on the direct seismic waves shows that the phased array technology explicit can influence the directional characteristics of the radiated seimic waves. The amplitudes of the seismic waves can be enhanced up to three times more in the desired direction and simultaneously be attenuated in the reverse direction. A major step for the directional investigation in boreholes has accomplished. But the focusing of the seismic waves has to be improved to maximize the energy in the desired direction in more measurements by calibrating the initiating seismic signals of the sources. A next step this year is the development of a wireline prototype for application in vertical boreholes with depths not more than 2000 meters are planned. The prototype must be modified and adapted to the conditions in deep boreholes with respect to pressure and temperature. This project is funded by the German Federal Environment Ministry.

Resource potential of the western North Atlantic Basin

USGS Publications Warehouse

Dillon, William P.; Manheim, Frank T.; Jansa, L.F.; Palmason, Gudmundur; Tucholke, Brian E.; Landrum, Richard S.

1986-01-01

We here consider the petroleum resources only of the off shelf portion of the western North Atlantic Ocean. Very little information is available for this region; off the eastern United States, only four petroleum exploration holes have been drilled in one restricted area seaward of the shelf, off the Baltimore Canyon trough. However, by interpreting seismic reflection profiles and Stratigraphie data from the Deep Sea Drilling Project (DSDP) and other wells on the adjacent slope and shelf, we can evaluate the geologic conditions that existed during development of the basin and that might lead to petroleum accumulations.The wellknown factors that lead to oil and gas accumulations are availability of source beds, adequate maturation, and the presence of reservoir beds and seals configured to create a trap. The western boundary of the area considered in this paper, the present sloperise break, is one that has developed from the interplay of sedimentation and erosion at the continental margin; these processes are affected by variations in margin subsidence, sedi-ment input, oceanic circulation, sea level, and other factors. Thus the sloperise break has migrated over time and is locally underlain by slope and shelf deposits, as well as deepbasin facies. These changes in depositional environments may well have caused juxtaposition of source and reservoir beds with effective seals.

Elemental Geochemistry of Samples From Fault Segments of the San Andreas Fault Observatory at Depth (SAFOD) Drill Hole

NASA Astrophysics Data System (ADS)

Tourscher, S. N.; Schleicher, A. M.; van der Pluijm, B. A.; Warr, L. N.

2006-12-01

Elemental geochemistry of mudrock samples from phase 2 drilling of the San Andreas Fault Observatory at Depth (SAFOD) is presented from bore hole depths of 3066 m to 3169 m and from 3292 m to 3368 m, which contain a creeping section and main trace of the fault, respectively. In addition to preparation and analysis of whole rock sample, fault grains with neomineralized, polished surfaces were hand picked from well-washed whole rock samples, minimizing the potential contamination from drilling mud and steel shavings. The separated fractions were washed in deionized water, powdered using a mortar and pestle, and analyzed using an Inductively Coupled Plasma- Optical Emission Spectrometer for major and minor elements. Based on oxide data results, systematic differences in element concentrations are observed between the whole rock and fault rock. Two groupings of data points are distinguishable in the regions containing the main trace of the fault, a shallow part (3292- 3316 m) and a deeper section (3320-3368 m). Applying the isocon method, assuming Zr and Ti to be immobile elements in these samples, indicates a volume loss of more than 30 percent in the shallow part and about 23 percent in the deep part of the main trace. These changes are minimum estimates of fault-related volume loss, because the whole rock from drilling samples contains variable amount of fault rock as well. Minimum estimates for volume loss in the creeping section of the fault are more than 50 percent when using the isocon method, comparing whole rock to plucked fault rock. The majority of the volume loss in the fault rocks is due to the dissolution and loss of silica, potassium, aluminum, sodium and calcium, whereas (based on oxide data) the mineralized surfaces of fractures appear to be enriched in Fe and Mg. The large amount of element mobility within these fault traces suggests extensive circulation of hydrous fluids along fractures that was responsible for progressive dissolution and leaching of the wall rock during faulting.

Optimization of geothermal well trajectory in order to minimize borehole failure

NASA Astrophysics Data System (ADS)

Dahrabou, A.; Valley, B.; Ladner, F.; Guinot, F.; Meier, P.

2017-12-01

In projects based on Enhanced Geothermal System (EGS) principle, deep boreholes are drilled to low permeability rock masses. As part of the completion operations, the permeability of existing fractures in the rock mass is enhanced by injecting large volumes of water. These stimulation treatments aim at achieving enough water circulation for heat extraction at commercial rates which makes the stimulation operations critical to the project success. The accurate placement of the stimulation treatments requires well completion with effective zonal isolation, and wellbore stability is a prerequisite to all zonal isolation techniques, be it packer sealing or cement placement. In this project, a workflow allowing a fast decision-making process for selecting an optimal well trajectory for EGS projects is developed. In fact, the well is first drilled vertically then based on logging data which are costly (100 KCHF/day), the direction in which the strongly deviated borehole section will be drilled needs to be determined in order to optimize borehole stability and to intersect the highest number of fractures that are oriented favorably for stimulation. The workflow applies to crystalline rock and includes an uncertainty and risk assessment framework. An initial sensitivity study was performed to identify the most influential parameters on borehole stability. The main challenge in these analyses is that the strength and stress profiles are unknown independently. Calibration of a geomechanical model on the observed borehole failure has been performed using data from the Basel Geothermal well BS-1. In a first approximation, a purely elastic-static analytical solution in combination with a purely cohesive failure criterion were used as it provides the most consistent prediction across failure indicators. A systematic analysis of the uncertainty on all parameters was performed to assess the reliability of the optimal trajectory selection. To each drilling scenario, failure probability and the associated risks, are computed stochastically. In addition, model uncertainty is assessed by confronting various failure modelling approaches to the available failure data from the Basel Project. Together, these results form the basis of an integrated workflow optimizing geothermal (EGS) well trajectory.

Examination of the Asian Monsoon: Ongoing Studies from IODP Expedition 346

NASA Astrophysics Data System (ADS)

Murray, R. W.; Tada, R.; Alvarez Zarikian, C. A.

2014-12-01

IODP Expedition 346 (Asian Monsoon) tested the hypothesis that Plio-Pleistocene uplift of the Himalaya and Tibetan Plateau, and/or emergence and growth of the northern hemisphere ice sheets and establishment of the two discrete modes of Westerly Jet circulation, is the cause of the millennial-scale variability of the East Asian summer monsoon (EASM) and amplification of Dansgaard-Oeschger cycles. We also examined whether the nature and strength of flow through the Tsushima Strait (which is strongly affected by EASM precipitation, sea level changes, and EAWM cooling) influenced surface and deepwater conditions of the Japan, Yamato, and Ulleung Basins. During only six weeks of drilling, Expedition 346 recovered 6135.3 m of core, which established an IODP record for the amount of recovered material. Because of recent advances in drilling technology and newly developed analytical tools, we were able to examine records that were impossible to acquire even a few years ago. The newly engineered half piston core system recovered the deepest piston core in DSDP/ODP/IODP history (490.4 m in Hole U1427A), which was reached by continuous piston coring from the seafloor. These advances delivered new surprises. We recovered pristine dark-light laminae from approximately 8 Ma sediment from 275 m below the seafloor at Site U1425 (Yamato Rise) and from 210 m below the seafloor (10-12 Ma) at Site U1430 in the Ulleung Basin. Aggressive sampling for geochemistry provided important constraints on the diagenetic and chemical environments throughout these marginal seas, and yet did not negatively compromise paleoceanographic objectives. We are extending earlier pioneering results of the Quaternary dark and light layers in these basins and which record variations of EASM precipitation over South China. Drilling in the East China Sea is providing an excellent record of EASM precipitation because its surface water salinity and temperature during summer is significantly influenced by Yangtze River discharge. Ash records are providing calibrated stratigraphic control and improving understanding of arc history. Interpreting these and other results in the context of other IODP drilling expeditions, such as Expedition 349 to the South China Sea, will be critical to develop a holistic understanding of the Asian monsoon system.

A 400 years isotope record of the Antarctic Peninsula climate

NASA Astrophysics Data System (ADS)

Aristarain, Alberto J.; Jouzel, Jean; Lorius, Claude

1990-12-01

A 400 year deuterium record has been obtained from a 154.3 m ice core drilled on Dalinger Dome (James Ross Island, Antarctic Peninsula). Based on a comparison between the isotope profile and the temperature data over the recent period (Aristarain et al, 1986), an interpretation is proposed in terms of temperature changes. The “warmest part” of this proxy record occurs around 1850 with, as a salient feature, a temperature decline of ˜ 2°C from that time up until present conditions. This feature, at odds with the long timescale warming trend recorded for both hemispheres over the same period, likely reflects a regional characteristic related to the lack of a high latitude/low latitude link in Southern hemisphere circulation patterns.

Results of an adaptive environmental assessment modeling workshop concerning potential impacts of drilling muds and cuttings on the marine environment

USGS Publications Warehouse

Auble, Gregor T.; Andrews, Austin K.; Ellison, Richard A.; Hamilton, David B.; Johnson, Richard A.; Roelle, James E.; Marmorek, David R.

1983-01-01

Drilling fluids or "muds" are essential components of modern drilling operations. They provide integrity for the well bore, a medium for removal of formation cuttings, and lubrication and cooling of the drill bit and pipe. The modeling workshop described in this report was conducted September 14-18, 1981 in Gulf Breeze, Florida to consider potential impacts of discharged drilling muds and cuttings on the marine environment. The broad goals of the workshop were synthesis of information on fate and effects, identification of general relationships between drilling fluids and the marine environment, and identification of site-specific variables likely to determine impacts of drilling muds and cuttings in various marine sites. The workshop was structured around construction of a model simulating fate and effects of discharges from a single rig into open water areas of the Gulf of Mexico, and discussion of factors that might produce different fate and effects in enclosed areas such as bays and estuaries. The simulation model was composed of four connected submodels. A Discharge/Fate submodel dealt with the discharge characteristics of the rig and the subsequent fate of discharged material. Three effects submodels then calculated biological responses at distances away from the rig for the water column, soft bottom benthos (assuming the rig was located over a soft bottom environment), and hard bottom benthos (assuming the rig was located over a hard bottom environment). The model focused on direct linkages between the discharge and various organisms rather than on how the marine ecosystem itself is interconnected. Behavior of the simulation model indicated relatively localized effects of drilling muds and cuttings discharged from a single platform into open water areas. Water column fate and effects were dominated by rapid dilution. Effects from deposition of spent mud and cuttings were spatially limited with relatively rapid recovery, especially in soft bottom benthic communities which were conceptualized as being adapted to frequent storms. This behavior was generated by the set of assumptions about linkages and functional relationships used to construct the model. Areas of uncertainty included methods for extrapolating 96-hr LC50 so results to exposures of varying lengths and concentrations; recovery rates of benthic communities; responses to various depths and rates of burial; fate and effects of the plume in relationship to stratification layers; and long-term and sub-lethal effects of slightly elevated concentrations of discharged materials. Evaluation of the assumptions of the Soft Bottom Submodel suggest that the assumptions used may have been relatively liberal estimates of resiliency of these communities. Discussion of "closed" water bodies such as bays and estuaries indicated several reasons to expect different and more complex fate and effects behavior in these areas. These factors included different species and communities (such as aquatic macrophytes and oyster beds), more complex circulation and stratification patterns, and potentially more active resuspension processes. Much of the possible difference in behavior in these areas centers around the extent to which they are “closed” or in the relative residence times of water and sediments in these areas as they determine the long-term dispersion of discharged material. Despite the complexity and variability of these areas, a large body of knowledge (such as that concerning fate and physical effects of dredge spoil) that could be effectively employed in analysis of potential fate and physical effects in enclosed areas was identified.

Structural Characterization of the Foliated-Layered Gabbro Transition in Wadi Tayin of the Samail Ophiolite, Oman; Oman Drilling Project Holes GT1A and GT2A

NASA Astrophysics Data System (ADS)

Deans, J. R.; Crispini, L.; Cheadle, M. J.; Harris, M.; Kelemen, P. B.; Teagle, D. A. H.; Matter, J. M.; Takazawa, E.; Coggon, J. A.

2017-12-01

Oman Drilling Project Holes GT1A and GT2A were drilled into the Wadi Tayin massif, Samail ophiolite and both recovered ca. 400 m of continuous core through a section of the layered gabbros and the foliated-layered gabbro transition. Hole GT1A is cut by a discrete fault system including localized thin ultracataclastic fault zones. Hole GT2A is cut by a wider zone of brittle deformation and incipient brecciation. Here we report the structural history of the gabbros reflecting formation at the ridge to later obduction. Magmatic and high temperature history- 1) Both cores exhibit a pervasive, commonly well-defined magmatic foliation delineated by plagioclase, olivine and in places clinopyroxene. Minor magmatic deformation is present. 2) The dip of the magmatic foliation varies cyclically, gradually changing dip by 30o from gentle to moderate over a 50 m wavelength. 3) Layering is present throughout both cores, is defined by changes in mode and grain size ranging in thickness from 2 cm to 3 m and is commonly sub-parallel to the foliation. 4) There are no high temperature crystal-plastic shear zones in the core. Key observations include: no simple, systematic shallowing of dip with depth across the foliated-layered gabbro transition and layering is continuous across this transition. Cyclic variation of magmatic foliation dip most likely reflects the process of plate separation at the ridge axis. Near-axis faulting- i) On or near-axis structures consist of epidote-amphibole bearing hydraulic breccias and some zones of intense cataclasis with intensely deformed epidote and seams of clay and chlorite accompanied by syntectonic alteration of the wall rock. Early veins are filled with amphibole, chlorite, epidote, and anhydrite. ii) The deformation ranges from brittle-ductile, causing local deflection of the magmatic foliation, to brittle offset of the foliation and core and mantle structures in anhydrite veins. iii) The prevalent sense of shear is normal and slickenfibers indicate oblique offset. Obduction related faulting- i) Low temperature brittle faults and veins with laumontite, clay, and gypsum crosscut all structures. ii) Faults show a reverse sense of shear and crosscut, possibly reactivate, normal faults. Our observations suggest formation of reverse faults and late veins during obduction of the ophiolite.

Forced Complementation between Subgenomic RNAs: Does Human Immunodeficiency Type 1 Virus Reverse Transcription Occur in Viral Core, Cytoplasm, or Early Endosome?

PubMed Central

Han, Weining; Li, Yuejin; Bagaya, Bernard S.; Tian, Meijuan; Chamanian, Mastooreh; Zhu, Chuanwu; Shen, Jie; Gao, Yong

2016-01-01

Although the process of reverse transcription is well elucidated, it remains unclear if viral core disruption provides a more cellular or viral milieu for HIV-1 reverse transcription. We have devised a method to require mixing of viral cores or core constituents to produce infectious progeny virus by a bipartite subgenomic RNA (sgRNA) system, in which HIV-1 cplt_R/U5/gag/Δpol and nfl sgRNAs are complementary to each other and when together can complete viral reverse transcription. Only the heterodiploid virus containing both the nfl and cplt_R/U5/gag/Δpol sgRNAs can complete reverse transcription and propagate infectious virus upon de novo infection. Dual exposure of U87.CD4.CXCR4 cells with high titers of the homodimeric nfl and cplt_R/U5/gag/Δpol virus particles did not result in productive virus infection. On the other hand, in early endosomes, the HIV-1 sgRNAs released from viral cores can retain function and complete the reverse transcription and result in productive infection. These findings confirm the assumptions that, in natural infection, HIV-1 cores, and likely other retrovirus cores, remain largely intact and do not mix/fuse in the cytoplasm during the reverse transcription process, and circulating cytoplasmic HIV-1 sgRNA (produced through transfection) could not help the complementary sgRNA in the viral core to complement the reverse transcription process. PMID:27239643

Oceanic link between abrupt changes in the North Atlantic Ocean and the African monsoon

NASA Astrophysics Data System (ADS)

Chang, Ping; Zhang, Rong; Hazeleger, Wilco; Wen, Caihong; Wan, Xiuquan; Ji, Link; Haarsma, Reindert J.; Breugem, Wim-Paul; Seidel, Howard

2008-07-01

Abrupt changes in the African monsoon can have pronounced socioeconomic impacts on many West African countries. Evidence for both prolonged humid periods and monsoon failures have been identified throughout the late Pleistocene and early Holocene epochs. In particular, drought conditions in West Africa have occurred during periods of reduced North Atlantic thermohaline circulation, such as the Younger Dryas cold event. Here, we use an ocean-atmosphere general circulation model to examine the link between oceanographic changes in the North Atlantic Ocean and changes in the strength of the African monsoon. Our simulations show that when North Atlantic thermohaline circulation is substantially weakened, the flow of the subsurface North Brazil Current reverses. This leads to decreased upper tropical ocean stratification and warmer sea surface temperatures in the equatorial South Atlantic Ocean, and consequently reduces African summer monsoonal winds and rainfall over West Africa. This mechanism is in agreement with reconstructions of past climate. We therefore suggest that the interaction between thermohaline circulation in the North Atlantic Ocean and wind-driven currents in the tropical Atlantic Ocean contributes to the rapidity of African monsoon transitions during abrupt climate change events.

A topographically forced asymmetry in the martian circulation and climate.

PubMed

Richardson, Mark I; Wilson, R John

2002-03-21

Large seasonal and hemispheric asymmetries in the martian climate system are generally ascribed to variations in solar heating associated with orbital eccentricity. As the orbital elements slowly change (over a period of >104 years), characteristics of the climate such as dustiness and the vigour of atmospheric circulation are thought to vary, as should asymmetries in the climate (for example, the deposition of water ice at the northern versus the southern pole). Such orbitally driven climate change might be responsible for the observed layering in Mars' polar deposits by modulating deposition of dust and water ice. Most current theories assume that climate asymmetries completely reverse as the angular distance between equinox and perihelion changes by 180 degrees. Here we describe a major climate mechanism that will not precess in this way. We show that Mars' global north-south elevation difference forces a dominant southern summer Hadley circulation that is independent of perihelion timing. The Hadley circulation, a tropical overturning cell responsible for trade winds, largely controls interhemispheric transport of water and the bulk dustiness of the atmosphere. The topography therefore imprints a strong handedness on climate, with water ice and the active formation of polar layered deposits more likely in the north.

Reciprocity relations in aerodynamics

NASA Technical Reports Server (NTRS)

Heaslet, Max A; Spreiter, John R

1953-01-01

Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis. A number of examples are listed, including general integral theorems for lifting, rolling, and pitching wings and for wings in nonuniform downwash fields. Correspondence is also established between the buildup of circulation with time of a wing starting impulsively from rest and the buildup of lift of the same wing moving in the reverse direction into a sharp-edged gust.

In Vitro Cross-Resistance Profiles of Rilpivirine, Dapivirine, and MIV-150, Nonnucleoside Reverse Transcriptase Inhibitor Microbicides in Clinical Development for the Prevention of HIV-1 Infection

PubMed Central

Giacobbi, Nicholas S.

2017-01-01

ABSTRACT Rilpivirine (RPV), dapivirine (DPV), and MIV-150 are in development as microbicides. It is not known whether they will block infection of circulating nonnucleoside reverse transcriptase inhibitor (NNRTI)-resistant human immunodeficiency virus type 1 (HIV-1) variants. Here, we demonstrate that the activity of DPV and MIV-150 is compromised by many resistant viruses containing single or double substitutions. High DPV genital tract concentrations from DPV ring use may block replication of resistant viruses. However, MIV-150 genital tract concentrations may be insufficient to inhibit many resistant viruses, including those harboring K103N or Y181C. PMID:28507107

Deep-sea ostracods from the South Atlantic sector of the Southern ocean during the Last 370,000 years

USGS Publications Warehouse

Yasuhara, Moriaki; Cronin, T. M.; Hunt, G.; Hodell, D.A.

2009-01-01

We report changes of deep-sea ostracod fauna during the last 370,000 yr from the Ocean Drilling Program (ODP) Hole 704A in the South Atlantic sector of the Southern Ocean. The results show that faunal changes are coincident with glacial/interglacial-scale deep-water circulation changes, even though our dataset is relatively small and the waters are barren of ostracods until mid-MIS (Marine Isotope Stage) 5. Krithe and Poseidonamicus were dominant during the Holocene interglacial period and the latter part of MIS 5, when this site was under the influence of North Atlantic Deep Water (NADW). Conversely, Henryhowella and Legitimocythere were dominant during glacial periods, when this site was in the path of Circumpolar Deep Water (CPDW). Three new species (Aversovalva brandaoae, Poseidonamicus hisayoae, and Krithe mazziniae) are described herein. This is the first report of Quaternary glacial/interglacial scale deep-sea ostracod faunal changes in the Southern and South Atlantic Oceans, a key region for understanding Quaternary climate and deep-water circulation, although the paucity of Quaternary ostracods in this region necessitates further research. ?? 2009 The Paleontological Society.

River Gardens Intermediate-Care Facility water-to-air heating and air-conditioning demonstration project. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, R.C.

An integrated system of heat pumps is used to reject heat into or extract heat from circulating water from a shallow well adjacent to the river to demonstrate the efficiency and fuel cost savings of water-to-air heat pumps, without the expense of drilling a deep well. Water is returned unpolluted to the Guadalupe River and is circulated through a five-building complex at River Gardens Intermediate Care Facility for the Mentally Retarded in New Braunfels, Texas. The water is used as a heat source or sink for 122 heat pumps providing space heating and cooling, and for refrigeration and freezer units.more » The system was not installed as designed, which resulted in water pumping loads being higher than the original design. Electrical consumption for pumping water represented 36 to 37% of system electrical consumption. Without the water pumping load, the water-to-air system was an average of 25% more efficient in heating than a comparable air-to-air unit with resistance heating. With water pumping load included, the installed system averaged 17% less efficient in cooling and 19% more efficient in heating than the comparable unit.« less

The role of zonally asymmetric heating in the vertical and temporal structure of the global scale flow fields during FGGE SOP-1. [First Global Atmospheric Research Program Global Experiment (FGGE); Special Observing Period (SOP)

NASA Technical Reports Server (NTRS)

Paegle, J.; Kalnay-Rivas, E.; Baker, W. E.

1981-01-01

By examining the vertical structure of the low order spherical harmonics of the divergence and vorticity fields, the relative contribution of tropical and monsoonal circulations upon the global wind fields was estimated. This indicates that the overall flow over North America and the Pacific between January and February is quite distinct both in the lower and upper troposphere. In these longitudes there is a stronger tropical overturning and subtropical jet stream in January than February. The divergent flow reversed between 850 and 200 mb. Poleward rotational flow at upper levels is associated with an equatorward rotational flow at low levels. This suggests that the monsoon and other tropical circulations project more amplitude upon low order (global scale) representations of the flow than do the typical midlatitude circulations and that their structures show conspicuous changes on a time scale of a week or less.

Magneto- and litho-stratigraphic records of the Oligocene-Early Miocene climatic changes from deep drilling in the Linxia Basin, Northeast Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wu, Fuli; Fang, Xiaomin; Meng, Qingquan; Zhao, Yan; Tang, Fenjun; Zhang, Tao; Zhang, Weilin; Zan, Jinbo

2017-11-01

The East Asian monsoon is generally regarded to have initiated at the transition from the Late Oligocene to the Early Miocene. However, little is known about this process because of a lack of continuous strata across the boundary between the Late Oligocene and the Early Miocene in Asia. Based on previous drilling (core HZ-1) in the Miocene sediments in the southern Linxia Basin in NW China, we drilled a new 620 m core (HZ-2) into the Late Oligocene strata and obtained 206 m of continuous new core. The detailed paleomagnetism of the new core reveals eleven pairs of normal and reversed polarity zones that can be readily correlated with chrons 6Bn-9n of the geomagnetic polarity time scale (GPTS), define an age interval of 21.6-26.5 Ma and indicate continuity from the Late Oligocene to Early Miocene. The core is characterized by the remarkable occurrence of brownish-red paleosols of luvic cambisols (brown to luvic drab soils) above reddish-brown floodplain siltstones and mudstones, which suggest that the East Asian monsoon likely began by 26.5 Ma. In contrast to the siltstone and mudstone of the Late Oligocene strata, the Miocene strata begin with a thick fine sandstone bed, which marks sudden increases in erosion and loading that most likely reflect a response to tectonic uplift. The hematite content and redness index records of the core further demonstrate that the monsoonal climate in the Late Oligocene to Early Miocene in this area was mainly controlled by global temperature trends and events.

Dacite Melt at the Puna Geothermal Venture Wellfield, Big Island of Hawaii

NASA Astrophysics Data System (ADS)

Teplow, W. J.; Marsh, B. D.; Hulen, J.; Spielman, P.; Kaleikini, M.; Fitch, D. C.; Rickard, W.

2008-12-01

A dacite melt was encountered during routine commercial drilling operations of injection well KS-13 at the Puna Geothermal Venture wellfield, Big Island of Hawaii. The KS-13 drill hole, drilled in 2005, is located along a segment of the Kilauea Lower East Rift Zone which erupted basalt flows from rift-parallel fissures in 1955. During the drilling of KS-13 a 75-meter interval of microdiorite containing brown glass inclusions was penetrated at a depth of 2415 m. At a depth of 2488 m a melt of dacitic composition was encountered. The melt flowed up the wellbore and was repeatedly redrilled over a depth interval of ~8 m, producing several kilograms of clear, colorless vitric cuttings at the surface. The drill bit, when recovered at the surface, was missing several carbide insert teeth. Presumably the inserts were plucked cleanly from their sintered cone sockets due to differential thermal expansion under extreme heat conditions. The dacitic glass cuttings have a perlitic texture, a silica content of 67 wgt.%, are enriched in alkalis and nearly devoid of mafic minerals with the exception of rare pyroxene phenocrysts and minor euhedral to amorphous magnetite. The melt zone is overlain by an interval of strong greenschist facies metamorphism in basaltic and dioritic dike rock. The occurrence of an anhydrous dacite melt indicates a rock temperature of approximately 1050° (1922°F) and sufficient residence time of underlying basaltic magma to generate a significant volume of differentiated material. The dacite, with an inferred temperature of 1050 °C, is separated by 526 m of rock from the deepest overlying permeable zone in KS-13 at a temperature of 356 °C. The thermal gradient through this impermeable rock section is ~700°C/526 m = 1.331 °C/m. The calculated conductive heat flux from the magma upward into the deepest zone of hydrothermal circulation is given by k×(dT/dZ)=2.9 × 1.33 = 3.83 W/m2 = 3830 mW/m2 (thermal conductivity k=2.9 W m-1 °C-1 for basalt). This heat flux is an order of magnitude greater than the average of 270-290 mW/ m2 typical for the mid-ocean ridges. The high heat flux is sufficient to power the overlying commercial geothermal wellfield which has been producing 28 MW of net electrical power continuously since 1993.

'End-stage' heart failure therapy: potential lessons from congenital heart disease: from pulmonary artery banding and interatrial communication to parallel circulation.

PubMed

Schranz, Dietmar; Akintuerk, Hakan; Voelkel, Norbert F

2017-02-15

The final therapy of 'end-stage heart failure' is orthotopic heart, lung or heart-lung transplantation. However, these options are not available for many patients worldwide. Therefore, novel therapeutical strategies are needed. Based on pathophysiological insights regarding (1) the long-term impact of an obstructive pulmonary outflow tract in neonates with congenitally corrected transposition of the great arteries, (2) the importance of a restrictive versus a non-restrictive atrial septum in neonates born with a borderline left ventricle and (3) the significance of both, a patent foramen ovale and/or open ductus arteriosus for survival of newborns with persistent pulmonary hypertension, the current review introduces some therapeutical strategies that may be applicable to selected patients with heart failure. These strategies include (1) reversible pulmonary artery banding in left ventricular-dilated cardiomyopathy with preserved right ventricular function, (2) the creation of restrictive interatrial communication to treat diastolic (systolic) heart failure, (3) atrioseptostomy or reverse Potts shunt in pulmonary arterial hypertension and (4) return to a fetal, parallel circulation by combining atrioseptostomy and reversed Potts shunt with or without placement of a bilateral pulmonary artery banding. While still being experimental, it is hoped that the procedures presented in the current overview will inspire future novel therapeutic strategies that may be applicable to selected patients with heart failure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Community Circulation Patterns of Oral Polio Vaccine Serotypes 1, 2, and 3 After Mexican National Immunization Weeks

PubMed Central

Troy, Stephanie B.; Ferreyra-Reyes, Leticia; Huang, ChunHong; Sarnquist, Clea; Canizales-Quintero, Sergio; Nelson, Christine; Báez-Saldaña, Renata; Holubar, Marisa; Ferreira-Guerrero, Elizabeth; García-García, Lourdes; Maldonado, Yvonne A.

2014-01-01

Background. With wild poliovirus nearing eradication, preventing circulating vaccine-derived poliovirus (cVDPV) by understanding oral polio vaccine (OPV) community circulation is increasingly important. Mexico, where OPV is given only during biannual national immunization weeks (NIWs) but where children receive inactivated polio vaccine (IPV) as part of their primary regimen, provides a natural setting to study OPV community circulation. Methods. In total, 216 children and household contacts in Veracruz, Mexico, were enrolled, and monthly stool samples and questionnaires collected for 1 year; 2501 stool samples underwent RNA extraction, reverse transcription, and real-time polymerase chain reaction (PCR) to detect OPV serotypes 1, 2, and 3. Results. OPV was detected up to 7 months after an NIW, but not at 8 months. In total, 35% of samples collected from children vaccinated the prior month, but only 4% of other samples, contained OPV. Although each serotype was detected in similar proportions among OPV strains shed as a result of direct vaccination, 87% of OPV acquired through community spread was serotype 2 (P < .0001). Conclusions. Serotype 2 circulates longer and is transmitted more readily than serotypes 1 or 3 after NIWs in a Mexican community primarily vaccinated with IPV. This may be part of the reason why most isolated cVDPV has been serotype 2. PMID:24367038

Superconducting analog-to-digital converter with a triple-junction reversible flip-flop bidirectional counter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, G.S.

1993-07-13

A high-performance superconducting analog-to-digital converter is described, comprising: a bidirectional binary counter having n stages of triple-junction reversible flip-flops connected together in a cascade arrangement from the least significant bit (LSB) to the most significant bit (MSB) where n is the number of bits of the digital output, each triple-junction reversible flip-flop including first, second and third shunted Josephson tunnel junctions and a superconducting inductor connected in a bridge circuit, the Josephson junctions and the inductor forming upper and lower portions of the flip-flop, each reversible flip-flop being a bistable logic circuit in which the direction of the circulating currentmore » determines the state of the circuit; and means for applying an analog input current to the bidirectional counter; wherein the bidirectional counter algebraically counts incremental changes in the analog input current, increasing the binary count for positive incremental changes in the analog current and decreasing the binary count for negative incremental changes in the current, and wherein the counter does not require a gate bias, thus minimizing power dissipation.« less

Geologic Analysis of Priority Basins for Exploration and Drilling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroll, H.B.; Reeves, T.K.

1999-04-27

There has been a substantial decline in both exploratory drilling and seismic field crew activity in the United States over the last 10 years, due primarily to the declining price of oil. To reverse this trend and to preserve the entrepreneurial independent operator, the U.S. DOE is attempting to encourage hydrocarbon exploration activities in some of the under exploited regions of the United States. This goal is being accomplished by conducting broad regional reviews of potentially prospective areas within the lower 48 states. Data are being collected on selected areas, and studies are being done on a regional scale generallymore » unavailable to the smaller independent. The results of this work will be made available to the public to encourage the undertaking of operations in areas which have been overlooked until this project. Fifteen criteria have been developed for the selection of study areas. Eight regions have been identified where regional geologic analysis will be performed. This report discusses preliminary findings concerning the geology, early tectonic history, structure and potential unconventional source rocks for the Black Mesa basin and South Central states region, the two highest priority study areas.« less

Optimizing drilling performance using a selected drilling fluid

DOEpatents

Judzis, Arnis [Salt Lake City, UT; Black, Alan D [Coral Springs, FL; Green, Sidney J [Salt Lake City, UT; Robertson, Homer A [West Jordan, UT; Bland, Ronald G [Houston, TX; Curry, David Alexander [The Woodlands, TX; Ledgerwood, III, Leroy W.

2011-04-19

To improve drilling performance, a drilling fluid is selected based on one or more criteria and to have at least one target characteristic. Drilling equipment is used to drill a wellbore, and the selected drilling fluid is provided into the wellbore during drilling with the drilling equipment. The at least one target characteristic of the drilling fluid includes an ability of the drilling fluid to penetrate into formation cuttings during drilling to weaken the formation cuttings.

Experimental analysis of drilling process in cortical bone.

PubMed

Wang, Wendong; Shi, Yikai; Yang, Ning; Yuan, Xiaoqing

2014-02-01

Bone drilling is an essential part in orthopaedics, traumatology and bone biopsy. Prediction and control of drilling forces and torque are critical to the success of operations involving bone drilling. This paper studied the drilling force, torque and drilling process with automatic and manual drill penetrating into bovine cortical bone. The tests were performed on a drilling system which is used to drill and measure forces and torque during drilling. The effects of drilling speed, feed rate and drill bit diameter on force and torque were discussed separately. The experimental results were proven to be in accordance with the mathematic expressions introduced in this paper. The automatic drilling saved drilling time by 30-60% in the tested range and created less vibration, compared to manual drilling. The deviation between maximum and average force of the automatic drilling was 5N but 25N for manual drilling. To conclude, using the automatic method has significant advantages in control drilling force, torque and drilling process in bone drilling. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

The key role of ozone depleting substances in weakening the Walker Circulation over the second half of the 20th Century

NASA Astrophysics Data System (ADS)

Bellomo, K.; Polvani, L. M.

2017-12-01

It is widely believed that the Walker Circulation will weaken in response to increasing greenhouse gases (GHG) by the end of the 21st century. But over the 20th century, the existence of a statistical significant weakening trends in the observations remains unclear. We here present new modelling evidence showing that Ozone Depleting Substances (ODS) may have significantly contributed to the weakening of the Walker Circulation over the years 1955-2005. While the primary impact of increasing ODS has been the formation of the ozone hole, it is perhaps not as widely appreciated that ODS are also powerful greenhouse gases. Using an ensemble of integrations with the the Whole Atmosphere Chemistry Climate Model, we show that the surface warming caused by increasing ODS over the second half of the 20th century causes a statistically significant weakening of the Walker Circulation in the model. In fact, we find that the increase of the other well-mixed GHG alone leads to a strengthening, not a weakening of the Walker Circulation, over that period in our model. When ODS concentrations are held fixed at 1950's levels, the effect of the other GHG is not sufficient, and a warming delay in the eastern tropical Pacific SST leads to an increase in the east-west SST gradient which is accompanied by a strengthening of the Walker Circulation. But, when the forcing from ODS is added in, the additional radiative forcing causes the eastern Pacific to warm faster, and the trend in the Walker Circulation reverses sign and becomes negative over the second half of the 20th century.

Effects of captopril on the human foetal placental circulation: an interaction with bradykinin and angiotensin I.

PubMed Central

de Moura, R; Lopes, M A

1995-01-01

1. The mechanism underlying the foetal toxicity induced by captopril is not well understood. Since bradykinin and angiotensin II appear to be important in the regulation of the placental circulation, experiments were performed to assess the effects of captopril on the vascular actions of these peptides on the human foetal placental circulation. 2. Full-term human placentas, obtained from normal pregnancy, were perfused with a modified Tyrode solution bubbled with O2 using a pulsatile pump. The placental perfusion pressure was measured with a Statham pressure transducer and recorded continuously on a Hewlett-Packard polygraph. 3. Bradykinin (0.1, 0.3 and 1.0 nmol) injected into the placental arterial circulation produced an increase in placental perfusion pressure in all experiments. This effect of bradykinin was significantly inhibited by indomethacin (3 x 10(-7) M). 4. Captopril (10(-7) M) significantly potentiated the pressor effect of bradykinin on the human placental circulation (n = 6). This effect of captopril was reversed by indomethacin (3 x 10(-7) M). 5. Angiotensin I (n = 6) and angiotensin II (n = 6), injected into the placental arterial circulation, both produced dose-dependent increases in placental perfusion pressure. The dose-response curves to angiotensin I (n = 6) were significantly displaced to the right by captopril in a concentration-dependent manner. 6. We suggest that the toxic effects of captopril on the foetus, rather than reflecting an inhibition of angiotensin II formation, may instead be related to a potentiation of the vasoconstrictor effect of bradykinin on the foetal placental circulation, thereby reducing blood flow and causing foetal damage. The reasons for this are discussed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7669485

Geothermal heating enhances atmospheric asymmetries on synchronously rotating planets

NASA Astrophysics Data System (ADS)

Haqq-Misra, Jacob; Kopparapu, Ravi Kumar

2015-01-01

Earth-like planets within the liquid water habitable zone of M-type stars may evolve into synchronous rotators. On these planets, the substellar hemisphere experiences perpetual daylight while the opposing antistellar hemisphere experiences perpetual darkness. Because the night-side hemisphere has no direct source of energy, the air over this side of the planet is prone to freeze out and deposit on the surface, which could result in atmospheric collapse. However, general circulation models (GCMs) have shown that atmospheric dynamics can counteract this problem and provide sufficient energy transport to the antistellar side. Here, we use an idealized GCM to consider the impact of geothermal heating on the habitability of synchronously rotating planets. Geothermal heating may be expected due to tidal interactions with the host star, and the effects of geothermal heating provide additional habitable surface area and may help to induce melting of ice on the antistellar hemisphere. We also explore the persistence of atmospheric asymmetries between the Northern and Southern hemispheres, and we find that the direction of the meridional circulation (for rapidly rotating planets) or the direction of zonal wind (for slowly rotating planets) reverses on either side of the substellar point. We show that the zonal circulation approaches a theoretical state similar to a Walker circulation only for slowly rotating planets, while rapidly rotating planets show a zonal circulation with the opposite direction. We find that a cross-polar circulation is present in all cases and provides an additional mechanism of mass and energy transport from the substellar to antistellar point. Characterization of the atmospheres of synchronously rotating planets should include consideration of hemispheric differences in meridional circulation and examination of transport due to cross-polar flow.

3D Groundwater flow model at the Upper Rhine Graben scale to delineate preferential target areas for geothermal projects

NASA Astrophysics Data System (ADS)

Armandine Les Landes, Antoine; Guillon, Théophile; Peter-Borie, Mariane; Rachez, Xavier

2017-04-01

Any deep unconventional geothermal project remains risky because of the uncertainty regarding the presence of the geothermal resource at depth and the drilling costs increasing accordingly. That's why this resource must be located as precisely as possible to increase the chances of successful projects and their economic viability. To minimize the risk, as much information as possible should be gathered prior to any drilling. Usually, the position of the exploration wells of geothermal energy systems is chosen based on structural geology observations, geophysics measurements and geochemical analyses. Confronting these observations to results from additional disciplines should bring more objectivity in locating the region to explore and where to implant the geothermal system. The Upper Rhine Graben (URG) is a tectonically active rift system that corresponds to one branch of the European Cenozoic Rift System where the basin hosts a significant potential for geothermal energy. The large fault network inherited from a complex tectonic history and settled under the sedimentary deposits hosts fluid circulation patterns. Geothermal anomalies are strongly influenced by fluid circulations within permeable structures such as fault zones. In order to better predict the location of the geothermal resource, it is necessary to understand how it is influenced by heat transport mechanisms such as groundwater flow. The understanding of fluid circulation in hot fractured media at large scale can help in the identification of preferential zones at a finer scale where additional exploration can be carried out. Numerical simulations is a useful tool to deal with the issue of fluid circulations through large fault networks that enable the uplift of deep and hot fluids. Therefore, we build a numerical model to study groundwater flow at the URG scale (150 x 130km), which aims to delineate preferential zones. The numerical model is based on a hybrid method using a Discrete Fracture Network (DFN) and 3D elements to simulate groundwater flow in the 3D regional fault network and in sedimentary deposits, respectively. Firstly, the geometry of the 3D fracture network and its hydraulic connections with 3D elements (sedimentary cover) is built in accordance with the tectonic history and based on geological and geophysical evidences. Secondly, data from previous studies and site-specific geological knowledge provide information on the fault zones family sets and on respective hydraulic properties. Then, from the simulated 3D groundwater flow model and based on a particle tracking methodology, groundwater flow paths are constructed. The regional groundwater flow paths results are extracted and analysed to delineate preferential zones to explore at finer scale and so to define the potential positions of the exploration wells. This work is conducted in the framework of the IMAGE project (Integrated Methods for Advanced Geothermal Exploration, grant agreement No. 608553), which aims to develop new methods for better siting of exploitation wells.

A major advance of tropical Andean glaciers during the Antarctic cold reversal.

PubMed

Jomelli, V; Favier, V; Vuille, M; Braucher, R; Martin, L; Blard, P-H; Colose, C; Brunstein, D; He, F; Khodri, M; Bourlès, D L; Leanni, L; Rinterknecht, V; Grancher, D; Francou, B; Ceballos, J L; Fonseca, H; Liu, Z; Otto-Bliesner, B L

2014-09-11

The Younger Dryas stadial, a cold event spanning 12,800 to 11,500 years ago, during the last deglaciation, is thought to coincide with the last major glacial re-advance in the tropical Andes. This interpretation relies mainly on cosmic-ray exposure dating of glacial deposits. Recent studies, however, have established new production rates for cosmogenic (10)Be and (3)He, which make it necessary to update all chronologies in this region and revise our understanding of cryospheric responses to climate variability. Here we present a new (10)Be moraine chronology in Colombia showing that glaciers in the northern tropical Andes expanded to a larger extent during the Antarctic cold reversal (14,500 to 12,900 years ago) than during the Younger Dryas. On the basis of a homogenized chronology of all (10)Be and (3)He moraine ages across the tropical Andes, we show that this behaviour was common to the northern and southern tropical Andes. Transient simulations with a coupled global climate model suggest that the common glacier behaviour was the result of Atlantic meridional overturning circulation variability superimposed on a deglacial increase in the atmospheric carbon dioxide concentration. During the Antarctic cold reversal, glaciers advanced primarily in response to cold sea surface temperatures over much of the Southern Hemisphere. During the Younger Dryas, however, northern tropical Andes glaciers retreated owing to abrupt regional warming in response to reduced precipitation and land-surface feedbacks triggered by a weakened Atlantic meridional overturning circulation. Conversely, glacier retreat during the Younger Dryas in the southern tropical Andes occurred as a result of progressive warming, probably influenced by an increase in atmospheric carbon dioxide. Considered with evidence from mid-latitude Andean glaciers, our results argue for a common glacier response to cold conditions in the Antarctic cold reversal exceeding that of the Younger Dryas.

Reversal of Apixaban Induced Alterations in Hemostasis by Different Coagulation Factor Concentrates: Significance of Studies In Vitro with Circulating Human Blood

PubMed Central

Arellano-Rodrigo, Eduardo; Roquer, Jaume; Reverter, Joan Carles; Sanz, Victoria Veronica; Molina, Patricia; Lopez-Vilchez, Irene; Diaz-Ricart, Maribel; Galan, Ana Maria

2013-01-01

Apixaban is a new oral anticoagulant with a specific inhibitory action on FXa. No information is available on the reversal of the antihemostatic action of apixaban in experimental or clinical settings. We have evaluated the effectiveness of different factor concentrates at reversing modifications of hemostatic mechanisms induced by moderately elevated concentrations of apixaban (200 ng/ml) added in vitro to blood from healthy donors (n = 10). Effects on thrombin generation (TG) and thromboelastometry (TEM) parameters were assessed. Modifications in platelet adhesive, aggregating and procoagulant activities were evaluated in studies with blood circulating through damaged vascular surfaces, at a shear rate of 600 s−1. The potential of prothrombin complex concentrates (PCCs; 50 IU/kg), activated prothrombin complex concentrates (aPCCs; 75 IU/kg), or activated recombinant factor VII (rFVIIa; 270 μg/kg), at reversing the antihemostatic actions of apixaban, were investigated. Apixaban interfered with TG kinetics. Delayed lag phase, prolonged time to peak and reduced peak values, were improved by the different concentrates, though modifications in TG patterns were diversely affected depending on the activating reagents. Apixaban significantly prolonged clotting times (CTs) in TEM studies. Prolongations in CTs were corrected by the different concentrates with variable efficacies (rFVIIa≥aPCC>PCC). Apixaban significantly reduced fibrin and platelet interactions with damaged vascular surfaces in perfusion studies (p<0.05 and p<0.01, respectively). Impairments in fibrin formation were normalized by the different concentrates. Only rFVIIa significantly restored levels of platelet deposition. Alterations in hemostasis induced by apixaban were variably compensated by the different factor concentrates investigated. However, effects of these concentrates were not homogeneous in all the tests, with PCCs showing more efficacy in TG, and rFVIIa being more effective on TEM and perfusion studies. Our results indicate that rFVIIa, PCCs and aPCCs have the potential to restore platelet and fibrin components of the hemostasis previously altered by apixaban. PMID:24244342

Drilling force and temperature of bone under dry and physiological drilling conditions

NASA Astrophysics Data System (ADS)

Xu, Linlin; Wang, Chengyong; Jiang, Min; He, Huiyu; Song, Yuexian; Chen, Hanyuan; Shen, Jingnan; Zhang, Jiayong

2014-11-01

Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systematic study of mid- and high-speed drilling under dry and physiological conditions(injection of saline). Furthermore, there is no consensus on optimal drilling parameters. To study these parameters under dry and physiological drilling conditions, pig humerus bones are drilled with medical twist drills operated using a wide range of drilling speeds and feed rates. Drilling force and temperature are measured using a YDZ-II01W dynamometer and a NEC TVS-500EX thermal infrared imager, respectively, to evaluate internal bone damage. To evaluate drilling quality, bone debris and hole morphology are observed by SEM(scanning electron microscopy). Changes in drilling force and temperature give similar results during drilling such that the value of each parameter peaks just before the drill penetrates through the osteon of the compact bone into the trabeculae of the spongy bone. Drilling temperatures under physiological conditions are much lower than those observed under dry conditions, while a larger drilling force occurs under physiological conditions than dry conditions. Drilling speed and feed rate have a significant influence on drilling force, temperature, bone debris and hole morphology. The investigation of the effect of drilling force and temperature on internal bone damage reveals that a drilling speed of 4500 r/min and a feed rate of 50 mm/min are recommended for bone drilling under physiological conditions. Drilling quality peaks under these optimal parameter conditions. This paper proposes the optimal drilling parameters under mid- and high-speed surgical drilling, considering internal bone damage and drilling quality, which can be looked as a reference for surgeons performing orthopedic operations.

A Babcock-Leighton solar dynamo model with multi-cellular meridional circulation in advection- and diffusion-dominated regimes

NASA Astrophysics Data System (ADS)

Belucz, B.; Dikpati, M.; Forgacs-Dajka, E.

2014-12-01

Babcock-Leighton type solar dynamo models with single cell meridional circulation are successful in reproducing many solarcycle features, and recently such a model was applied for solarcycle 24 amplitude prediction. It seems that cycle 24 amplitudeforecast may not be validated. One of the reasons is the assumption of a single cell meridional circulation. Recent observations andtheoretical models of meridional circulation do not indicate a single-celledflow pattern. So it is nessecary to examine the role of complexmulti-cellular circulation patterns in a Babcock-Leighton solar dynamo model in the advection and diffusion dominated regimes.By simulating a Babcock-Leighton solar dynamo model with multi-cellularflow, we show that the presence of a weak, second, high-latitudereverse cell speeds up the cycle and slighty enhances the poleward branch in the butterfly diagram, whereas the presence of a second cellin depth reverses the tilt of the butterfly wing and leads to ananti-solar type feature. If, instead, the butterfly diagram isconstructed from the middle of the convection zone in that case, a solar-like pattern can be retrieved. All the above cases behavequalitatively similar in advection and diffusion-dominated regimes.However, our dynamo with a meridional circulation containing fourcells in latitude behaves distinctly different in the two regimes, producing a solar-like butterfly diagram with fast cycles indiffusion-dominated regime, and a complex branches in the butterflydiagram in the advection-dominated regime. Another interestingfinding from our studies is that a four-celled flow pattern containing two in radius and two in latitude always producesquadrupolar parity as the relaxed solution.

Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice.

PubMed

Watabe, Takahisa; Xu, Ming; Watanabe, Miho; Nabekura, Junichi; Higuchi, Taiga; Hori, Karin; Sato, Mitsuo P; Nin, Fumiaki; Hibino, Hiroshi; Ogawa, Kaoru; Masuda, Masatsugu; Tanaka, Kenji F

2017-10-19

Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K + circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.

An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

TerraTek

2007-06-30

A deep drilling research program titled 'An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration' was conducted at TerraTek's Drilling and Completions Laboratory. Drilling tests were run to simulate deep drilling by using high bore pressures and high confining and overburden stresses. The purpose of this testing was to gain insight into practices that would improve rates of penetration and mechanical specific energy while drilling under high pressure conditions. Thirty-seven test series were run utilizing a variety of drilling parameters which allowed analysis of the performance ofmore » drill bits and drilling fluids. Five different drill bit types or styles were tested: four-bladed polycrystalline diamond compact (PDC), 7-bladed PDC in regular and long profile, roller-cone, and impregnated. There were three different rock types used to simulate deep formations: Mancos shale, Carthage marble, and Crab Orchard sandstone. The testing also analyzed various drilling fluids and the extent to which they improved drilling. The PDC drill bits provided the best performance overall. The impregnated and tungsten carbide insert roller-cone drill bits performed poorly under the conditions chosen. The cesium formate drilling fluid outperformed all other drilling muds when drilling in the Carthage marble and Mancos shale with PDC drill bits. The oil base drilling fluid with manganese tetroxide weighting material provided the best performance when drilling the Crab Orchard sandstone.« less

The detection of melanoma cells in peripheral blood by reverse transcription-polymerase chain reaction.

PubMed Central

Foss, A. J.; Guille, M. J.; Occleston, N. L.; Hykin, P. G.; Hungerford, J. L.; Lightman, S.

1995-01-01

Both cutaneous and uveal melanoma undergo haematogenous dissemination. Detection of tyrosinase mRNA by reverse transcription-polymerase chain reaction (RT-PCR) has been described as an extremely sensitive way of detecting circulating viable melanoma cells in the peripheral venous blood, and this technique may be of value in the early detection of dissemination. Also, it has been suggested that surgical manipulation of the eye, such as occurs during enucleation, can provoke uveal melanoma dissemination. The purpose of this study was to evaluate whether tyrosinase mRNA is detectable in the peripheral blood of patients with uveal and cutaneous melanoma and in patients with uveal melanoma undergoing surgical procedures on the eye harbouring the tumour. Venous blood samples from 36 patients diagnosed as having active uveal melanoma and from six patients with advanced metastatic cutaneous melanoma were analysed. In addition, blood samples were spiked with known numbers of cells from three cell lines and four primary uveal melanoma cultures. The reported sensitivity of the technique was confirmed, with an ability to detect down to one cell per ml of blood. All 51 blood samples from the 36 patients with uveal melanoma were negative, and this included 20 perioperative blood samples. The test was also negative for the six patients with advanced cutaneous melanoma. There were two positives among 31 control samples analysed. This study demonstrates that there are far fewer circulating viable melanocytes than has been previously supposed in patients with melanoma and that the RT-PCR is of no clinical value in detecting metastatic melanoma disease. There was no evidence for surgery causing a bolus of melanoma cells to enter the peripheral circulation. Images Figure 1 Figure 2 PMID:7599046

Simple and rapid LC-MS method for the determination of circulating albumin microheterogeneity in veal calves exposed to heat stress.

PubMed

Baldassarre, Maurizio; Naldi, Marina; Domenicali, Marco; Volo, Sabrina; Pietra, Marco; Dondi, Francesco; Caraceni, Paolo; Peli, Angelo

2017-09-10

Heat stress has a major impact on veal calves welfare and productivity. Prolonged exposure to warm temperature is associated with several alterations of physiologic processes and increased systemic inflammation and oxidative stress. Bovine serum albumin (BSA) is the most abundant plasma protein and, besides the regulation of osmotic pressure, carries several additional functions, including antioxidant, immunomodulatory, binding and transport activities. Such non-oncotic properties are closely related to structural integrity of the circulating molecule and may be compromised in stressful microenvironments as it occurs in heat stressed animals. Thus, in the present study we developed and validated an LC-MS analytical technique for the characterization of circulating BSA microheterogeneity in veal calves exposed to heat stress. The method was specifically tailored to the structural characteristics of the BSA molecule as well as to the complexity of the biological samples, allowing the identification of several BSA isoforms, each characterized by a specific structural defect. The mass spectrometry based approach enabled the identification of BSA isoforms with reversible and irreversible oxidation and/or glycation and the native BSA, the only isoform endowed with structural and functional integrity. We found that, in veal calves, heat stress is associated to a significant reduction of the native BSA and to a significant increment of the reversibly and irreversibly oxidized BSA. Then, by monitoring the BSA microheterogeneity over a period of moderate heat stress, we found that the native BSA as well as the glycated BSA increased significantly during the recovery period. Based on our results the analysis of the BSA microheterogeneity could represent a novel biomarker for the assessment of animal welfare during environmental stressful conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Exercise training improves function of circulating angiogenic cells in patients with chronic heart failure.

PubMed

Van Craenenbroeck, Emeline M; Hoymans, Vicky Y; Beckers, Paul J; Possemiers, Nadine M; Wuyts, Kurt; Paelinck, Bernard P; Vrints, Christiaan J; Conraads, Viviane M

2010-09-01

Alterations in circulating angiogenic cells (CAC) and endothelial progenitor cells (EPC), known to contribute to endothelial repair, could explain the reversal of endothelial function in response to exercise training. Moreover, training-induced vascular remodeling might affect the acute response of EPC and CAC following a single exercise bout. We studied the impact of exercise training on CAC function and numbers of CD34(+)/KDR(+) EPC in patients with chronic heart failure (CHF) and we assessed the effect of acute exercise on CAC and EPC in sedentary and trained patients. Twenty-one sedentary CHF patients underwent 6-month exercise training and were compared to a non-trained control group (n = 17) and 10 healthy age-matched subjects. At baseline and follow-up, flow-mediated dilation was assessed and graded exercise testing (GXT) was performed. Before and immediately after GXT, CAC migratory capacity was assessed in vitro and circulating CD34(+)/KDR(+) EPC were quantified using flow cytometry. At baseline, CAC migration was significantly impaired in sedentary CHF patients but normalized acutely after GXT. Training corrected endothelial dysfunction, which coincided with a 77% increase in CAC migration (P = 0.0001). Moreover, the GXT-induced improvement detected at baseline was no longer observed after training. Numbers of CD34(+)/KDR(+) EPC increased following 6-month exercise training (P = 0.021), but were not affected by GXT, either prior or post-training. In conclusion, the present findings demonstrate for the first time that exercise training in CHF reverses CAC dysfunction and increases numbers of CD34(+)/KDR(+) EPC, which is accompanied by improvement of peripheral endothelial function. The acute exercise-induced changes in CAC function wane with exercise training, suggesting that repetitive exercise bouts progressively lead to functional endothelial repair.

Isolation of sabin-like polioviruses from wastewater in a country using inactivated polio vaccine.

PubMed

Zurbriggen, Sebastian; Tobler, Kurt; Abril, Carlos; Diedrich, Sabine; Ackermann, Mathias; Pallansch, Mark A; Metzler, Alfred

2008-09-01

From 2001 to 2004, Switzerland switched from routine vaccination with oral polio vaccine (OPV) to inactivated polio vaccine (IPV), using both vaccines in the intervening period. Since IPV is less effective at inducing mucosal immunity than OPV, this change might allow imported poliovirus to circulate undetected more easily in an increasingly IPV-immunized population. Environmental monitoring is a recognized tool for identifying polioviruses in a community. To look for evidence of poliovirus circulation following cessation of OPV use, two sewage treatment plants located in the Zurich area were sampled from 2004 to 2006. Following virus isolation using either RD or L20B cells, enteroviruses and polioviruses were identified by reverse transcription-PCR. A total of 20 out of 174 wastewater samples were positive for 62 Sabin-like isolates. One isolate from each poliovirus-positive sample was analyzed in more detail. Sequencing the complete viral protein 1 (VP1) capsid coding region, as well as intratypic differentiation (ITD), identified 3 Sabin type 1, 13 Sabin type 2, and 4 Sabin type 3 strains. One serotype 1 strain showed a discordant result in the ITD. Three-quarters of the strains showed mutations within the 5' untranslated region and VP1, known to be associated with reversion to virulence. Moreover, three strains showed heterotypic recombination (S2/S1 and S3/S2/S3). The low number of synonymous mutations and the partial temperature sensitivity are not consistent with extended circulation of these Sabin virus strains. Nevertheless, the continuous introduction of polioviruses into the community emphasizes the necessity for uninterrupted child vaccination to maintain high herd immunity.

Platelet Dynamics during Natural and Pharmacologically Induced Torpor and Forced Hypothermia

PubMed Central

de Vrij, Edwin L.; Vogelaar, Pieter C.; Goris, Maaike; Houwertjes, Martin C.; Herwig, Annika; Dugbartey, George J.; Boerema, Ate S.; Strijkstra, Arjen M.; Bouma, Hjalmar R.; Henning, Robert H.

2014-01-01

Hibernation is an energy-conserving behavior in winter characterized by two phases: torpor and arousal. During torpor, markedly reduced metabolic activity results in inactivity and decreased body temperature. Arousal periods intersperse the torpor bouts and feature increased metabolism and euthermic body temperature. Alterations in physiological parameters, such as suppression of hemostasis, are thought to allow hibernators to survive periods of torpor and arousal without organ injury. While the state of torpor is potentially procoagulant, due to low blood flow, increased viscosity, immobility, hypoxia, and low body temperature, organ injury due to thromboembolism is absent. To investigate platelet dynamics during hibernation, we measured platelet count and function during and after natural torpor, pharmacologically induced torpor and forced hypothermia. Splenectomies were performed to unravel potential storage sites of platelets during torpor. Here we show that decreasing body temperature drives thrombocytopenia during torpor in hamster with maintained functionality of circulating platelets. Interestingly, hamster platelets during torpor do not express P-selectin, but expression is induced by treatment with ADP. Platelet count rapidly restores during arousal and rewarming. Platelet dynamics in hibernation are not affected by splenectomy before or during torpor. Reversible thrombocytopenia was also induced by forced hypothermia in both hibernating (hamster) and non-hibernating (rat and mouse) species without changing platelet function. Pharmacological torpor induced by injection of 5′-AMP in mice did not induce thrombocytopenia, possibly because 5′-AMP inhibits platelet function. The rapidness of changes in the numbers of circulating platelets, as well as marginal changes in immature platelet fractions upon arousal, strongly suggest that storage-and-release underlies the reversible thrombocytopenia during natural torpor. Possibly, margination of platelets, dependent on intrinsic platelet functionality, governs clearance of circulating platelets during torpor. PMID:24722364

Enhanced Geothermal Systems (EGS) - Where Are We Now

NASA Astrophysics Data System (ADS)

Wyborn, D.

2011-12-01

There were seven major EGS projects in which reservoir circulation was achieved prior to the Geodynamics Limited project in the Innamincka granite in northern South Australia which commenced in 2002. Six other projects did not achieve significant circulation. Importantly all but one of these projects were located in granitic bodies in which it is assumed that families of existing natural fractures are present. Evidence from all these EGS projects indicated that: 1 Stimulation in granite rock resulting from water injection with no added chemicals enhanced rock fracture permeability by 2-3 orders of magnitude. 2 The increased permeability resulted from increased fracture porosity associated with slippage on existing natural fractures during the stimulation. 3The extent of the resulting reservoir could be accurately mapped by acoustic (micro-seismic) monitoring of the fracture slippages. 4 The orientation of the reservoir is strongly dependent on the relative directions of the three principle rock stress axes. 5 The stimulation pumping pressures required were 50-75% of the minimum principle stress for the depth of reservoir creation in accord with geomechanical theory, and are therefore lower than those required to open tensile fractures (fracking). 6 The size of the resulting stimulated reservoir is proportional to the volume of water injected. New space created by the increase in fracture porosity associated with the micro-seismic events is taken up by the injected water. 7 Most projects to 2002 were carried out in strike-slip and normal faulting stress regimes with minimum stress direction horizontal and the resulting reservoirs were oriented close to vertically. 8 Volcanic activity can only occur in strike-slip and normal faulting stress regimes so EGS reservoirs in volcanic areas will be oriented close to vertically. 9 The Fjallbacka project in Sweden was the only project carried out in an overthrust stress regime (minimum stress direction vertical) and the reservoir was oriented horizontally. It is with these understandings that the Geodynamics field program commenced near Innamincka in 2002 where high temperature granite basement had been intersected at 3.6 km depth by petroleum exploration wells. Gravity and heat flow models indicated the basement granite to be 10 km thick and that most of the heat flow (> 100 mW/m2) was derived from elevated thorium and uranium levels in the granite. The stress environment was thought to be overthrust, but this was not certain.The results of the Geodynamics field program consists of drilling 5 wells to the granite, stimulation in three of those wells, flow testing in two of those wells and circulation between two of those wells. There are now four main barriers to economic deployment of EGS throughout the world for electricity generation. One is the cost of drilling and new technologies need to be developed to increase drilling ROP in high strength rocks. The other three relate to reservoir development and increased flow rate. These are (i) new geophysical tools to locate large fractures remotely (ii) deployment of temporary fracture sealing agents to allow enhancement in more than one fracture, and (iii) decreased flow impedance in a given fracture at the production well. New projects at different locations around the world are required to test ways of overcoming these barriers.

Stress and Pore Pressure Measurement in IODP Riser Drilling: An Example from Expedition 319, Kumano Basin offshore SW Honshu, Japan

NASA Astrophysics Data System (ADS)

Saffer, D. M.; McNeill, L. C.; Byrne, T. B.; Araki, E.; Flemings, P. B.; Conin, M.; Eguchi, N. O.; Takahashi, K.; Toczko, S.; Boutt, D. F.; Doan, M.; Kano, Y.; Ito, T.; Lin, W.

2009-12-01

In summer 2009, Integrated Ocean Drilling Program (IODP) Expedition 319 drilled a 1600 m deep riser borehole (Site C0009) in the Kumano Basin offshore SW Japan, to investigate the properties, structure and state of stress in the hanging wall above the subduction plate boundary. The first riser-based scientific drilling in IODP history allowed us to make several new scientific measurements including in situ stress magnitude, pore pressure and permeability using the Modular Formation Dynamics Tester (MDT) wireline tool, and measurement of minimum stress magnitude from Leak-off Tests (LOT). In addition, continuous monitoring of mud weight, mud gas, annular pressure, and mud losses provided data to constrain formation pore fluid pressure and stress. At Site C0009, we conducted 2 LOTs below a casing shoe at 708.6 m depth and 11 successful MDT measurements, including 9 single probe tests to measure pore pressure and fluid mobility and 2 dual packer tests: 1 to measure permeability by a drawdown test, and 1 to measure in situ stress. Measured pore pressures are approximately hydrostatic to 1463.7 m depth. We observed only minor gas shows when drilling ahead (as in-place methane was liberated from the rock at the bit) but little or no gas during pipe connections. This indicates that the borehole mud pressure exceeded the formation pore pressure, and is consistent with the MDT measurements. Permeabilities range from ~10-16 m2 - 10-14 m2, and the observed variation is consistent with lithologic changes defined in gamma ray logs. The MDT measurement at 874.3 mbsf and the LOT at 708.6 m yield values for the least principal stress of 34.8 MPa and 30.2 MPa, respectively. Both are less than the vertical stress (Sv) computed from density logs. Partial mud circulation losses occurred when the borehole mud pressure exceeded the leak-off stress measured at the base of the casing shoe; this provides an additional indirect constraint on Shmin magnitude. Mud pressure slightly in excess of the leak-off stress may have also generated poorly-developed drilling-induced tensile fractures (DITF) observed in resistivity image logs between ~750 - 1000 m. From the presence of DITF, Shmin measurements, and assuming a rock tensile strength of 1 MPa, we determine that SHmax is 35.1 MPa for the MDT stress measurement, and 30.2 MPa for the LOT. Using the MDT measurement of Shmin, the resulting principal stress magnitudes define a strike-slip faulting regime with effective stresses of Shmax’ = 14 MPa, Sv' = 7.3 MPa, and Shmin’ = 6.4 MPa. In contrast, using the LOT measurement of Shmin, the stress magnitudes indicate a normal faulting regime in which Sv’ = 6.2 MPa, Shmax’ = 2.8 MPa, and Shmin’ = 2.6 MPa.

A viable circulating tumor cell isolation device with high retrieval efficiency using a reversibly deformable membrane barrier

NASA Astrophysics Data System (ADS)

Kim, Yoonji; Bu, Jiyoon; Cho, Young-Ho; Son, Il Tae; Kang, Sung-Bum

2017-02-01

Circulating tumor cells (CTCs) contain prognostic information of the tumor, since they shed from the primary tumor and invade into the bloodstream. Therefore, the viable isolation is necessary for a consequent analysis of CTCs. Here, we present a device for the viable isolation and efficient retrieval of CTCs using slanted slot filters, formed by a reversibly deformable membrane barrier. Conventional filters have difficulties in retrieving captured cells, since they easily clog the slots. Moreover, large stress concentration at the sharp edges of squared slots, causes cell lysis. In contrast, the present device shows over 94% of high retrieval efficiency, since the slots can be opened simply by relieving the pressure. Furthermore, the inflated membrane barrier naturally forms the slanted slots, thus reducing the cell damage. By using cancer cell lines, we verified that the present device successfully isolate targeted cells, even at an extremely low concentrations (~10 cells/0.1 ml). In the clinical study, 85.7% of patients initially showed CTC positive while the numbers generally decreased after the surgery. We have also proved that the number of CTCs were highly correlated with tumour invasiveness. Therefore, the present device has potential for use in cancer diagnosis, surgical validation, and invasiveness analysis.

In Vitro Cross-Resistance Profiles of Rilpivirine, Dapivirine, and MIV-150, Nonnucleoside Reverse Transcriptase Inhibitor Microbicides in Clinical Development for the Prevention of HIV-1 Infection.

PubMed

Giacobbi, Nicholas S; Sluis-Cremer, Nicolas

2017-07-01

Rilpivirine (RPV), dapivirine (DPV), and MIV-150 are in development as microbicides. It is not known whether they will block infection of circulating nonnucleoside reverse transcriptase inhibitor (NNRTI)-resistant human immunodeficiency virus type 1 (HIV-1) variants. Here, we demonstrate that the activity of DPV and MIV-150 is compromised by many resistant viruses containing single or double substitutions. High DPV genital tract concentrations from DPV ring use may block replication of resistant viruses. However, MIV-150 genital tract concentrations may be insufficient to inhibit many resistant viruses, including those harboring K103N or Y181C. Copyright © 2017 American Society for Microbiology.

Effects of a Short Drilling Implant Protocol on Osteotomy Site Temperature and Drill Torque.

PubMed

Mihali, Sorin G; Canjau, Silvana; Cernescu, Anghel; Bortun, Cristina M; Wang, Hom-Lay; Bratu, Emanuel

2018-02-01

To establish a protocol for reducing the drilling sequence during implant site preparation based on temperature and insertion torque. The traditional conventional drilling sequence (used several drills with 0.6-mm increment each time) was compared with the proposed short drilling protocol (only used 2 drills: initial and final drill). One hundred drilling osteotomies were performed in bovine and porcine bones. Sets of 2 osteotomy sites were created in 5 bone densities using 2 types of drilling protocols. Thermographic pictures were captured throughout all drilling procedures and analyzed using ThermaCAM Researcher Professional 2.10. Torque values were determined during drilling by measuring electrical input and drill speed. There were statistically significant differences in bone temperature between the conventional and short drilling protocols during implant site preparation (analysis of variance P = 0.0008). However, there were no significant differences between the 2 types of drilling protocols for both implant diameters. Implant site preparation time was significantly reduced when using the short drilling protocol compared with the conventional drilling protocol (P < 0.001). Within the limitations of the study, the short drilling protocol proposed herein may represent a safe approach for implant site preparation.

Advantages and limitations of remotely operated sea floor drill rigs

NASA Astrophysics Data System (ADS)

Freudenthal, T.; Smith, D. J.; Wefer, G.

2009-04-01

A variety of research targets in marine sciences including the investigation of gas hydrates, slope stability, alteration of oceanic crust, ore formation and palaeoclimate can be addressed by shallow drilling. However, drill ships are mostly used for deep drillings, both because the effort of building up a drill string from a drill ship to the deep sea floor is tremendous and control on drill bit pressure from a movable platform and a vibrating drill string is poor especially in the upper hundred meters. During the last decade a variety of remotely operated drill rigs have been developed, that are deployed on the sea bed and operated from standard research vessels. These developments include the BMS (Bentic Multicoring System, developed by Williamson and Associates, operated by the Japanese Mining Agency), the PROD (Portable Remotely Operated Drill, developed and operated by Benthic Geotech), the Rockdrill 2 (developed and operated by the British geological Survey) and the MeBo (German abbreviation for sea floor drill rig, developed and operated by Marum, University of Bremen). These drill rigs reach drilling depths between 15 and 100 m. For shallow drillings remotely operated drill rigs are a cost effective alternative to the services of drill ships and have the major advantage that the drilling operations are performed from a stable platform independent of any ship movements due to waves, wind or currents. Sea floor drill rigs can be deployed both in shallow waters and the deep sea. A careful site survey is required before deploying the sea floor drill rig. Slope gradient, small scale topography and soil strength are important factors when planning the deployment. The choice of drill bits and core catcher depend on the expected geology. The required drill tools are stored on one or two magazines on the drill rig. The MeBo is the only remotely operated drill rig world wide that can use wire line coring technique. This method is much faster than conventional drilling. It has the advantage that the drill string stays in the drilled hole during the entire drilling process and prevents the drilled hole from collapsing while the inner core barrels comprising the drilled core sections are hooked up inside the drill string using a wire.

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression.

PubMed

Amaya, Ronny; Cancel, Limary M; Tarbell, John M

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle-SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease.

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression

PubMed Central

Amaya, Ronny; Cancel, Limary M.; Tarbell, John M.

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle–SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease. PMID:27846267

Initiation of long-term coupled microbiological, geochemical, and hydrological experimentation within the seafloor at North Pond, western flank of the Mid-Atlantic Ridge

USGS Publications Warehouse

Edwards, K.J.; Backert, N.; Bach, W.; Becker, K.; Klaus, A.; Griffin, Dale W.; Anderson, L.; Haddad, A.G.; Harigane, Y.; Campion, P.L.; Hirayama, H.; Mills, H.J.; Hulme, S.M.; Nakamura, K.; Jorgensen, S.L.; Orcutt, B.; Insua, T.L.; Park, Y.-S.; Rennie, V.; Salas, E.C.; Rouxel, O.; Wang, F.; Russel, J.A.; Wheat, C.G.; Sakata, K.; Brown, M.; Magnusson, J.L.; Ettlinger, Z.

2012-01-01

Integrated Ocean Drilling Program (IODP) Expedition 336 successfully initiated subseafloor observatory science at a young mid-ocean-ridge flank setting. All of the drilled sites are located in the North Pond region of the Atlantic Ocean (22??45'N, 46??05'W) in 4414-4483 m water depth. This area is known from previous ocean drilling and site survey investigations as a site of particularly vigorous circulation of seawater in permeable 8 Ma basaltic basement underlying a <300 m thick sedimentary pile. Understanding how this seawater circulation affects microbial and geochemical processes in the uppermost basement was the primary science objective of Expedition 336. Basement was cored and wireline-logged in Holes U1382A and U1383C. Upper oceanic crust in Hole U1382A, which is only 50 m west of Deep Sea Drilling Project (DSDP) Hole 395A, recovered 32 m of core between 110 and 210 meters below seafloor (mbsf). Core recovery in basement was 32%, yielding a number of volcanic flow units with distinct geochemical and petrographic characteristics. A unit of sedimentary breccia containing clasts of basalt, gabbroic rocks, and mantle peridotite was found intercalated between two volcanic flow units and was interpreted as a rock slide deposit. From Hole U1383C we recovered 50.3 m of core between 69.5 and 331.5 mbsf (19%). The basalts are aphyric to highly plagioclase-olivine-phyric tholeiites that fall on a liquid line of descent controlled by olivine fractionation. They are fresh to moderately altered, with clay minerals (saponite, nontronite, and celadonite), Fe oxyhydroxide, carbonate, and zeolite as secondary phases replacing glass and olivine to variable extents. In addition to traditional downhole logs, we also used a new logging tool for detecting in situ microbial life in ocean floor boreholes-the Deep Exploration Biosphere Investigative tool (DEBI-t). Sediment thickness was ???90 m at Sites U1382 and U1384 and varied between 38 and 53 m at Site U1383. The sediments are predominantly nannofossil ooze with layers of coarse foraminiferal sand and occasional pebble-size clasts of basalt, serpentinite, gabbroic rocks, and bivalve debris. The bottommost meters of sections cored with the advanced piston corer feature brown clay. Extended core barrel coring at the sediment/basement interface recovered <1 m of brecciated basalt with micritic limestone. Sediments were intensely sampled for geochemical pore water analyses and microbiological work. In addition, high-resolution measurements of dissolved oxygen concentration were performed on the whole-round sediment cores. Major strides in ridge-flank studies have been made with subseafloor borehole observatories (CORKs) because they facilitate combined hydrological, geochemical, and microbiological studies and controlled experimentation in the subseafloor. During Expedition 336, two fully functional observatories were installed in two newly drilled holes (U1382A and U1383C) and an instrument and sampling string were placed in an existing hole (395A). Although the CORK wellhead in Hole 395A broke off and Hole U1383B was abandoned after a bit failure, these holes and installations are intended for future observatory science targets. The CORK observatory in Hole U1382A has a packer seal in the bottom of the casing and monitors/samples a single zone in uppermost oceanic crust extending from 90 to 210 mbsf. Hole U1383C was equipped with a three-level CORK observatory that spans a zone of thin basalt flows with intercalated limestone (???70-146 mbsf), a zone of glassy, thin basaltic flows and hyaloclastites (146-200 mbsf), and a lowermost zone (???200-331.5 mbsf) of more massive pillow flows with occasional hyaloclastites in the upper part.

A Possible Link Between Winter Arctic Sea Ice Decline and a Collapse of the Beaufort High?

NASA Astrophysics Data System (ADS)

Petty, Alek A.

2018-03-01

A new study by Moore et al. (2018, https://doi.org/10.1002/2017GL076446) highlights a collapse of the anticyclonic "Beaufort High" atmospheric circulation over the western Arctic Ocean in the winter of 2017 and an associated reversal of the sea ice drift through the southern Beaufort Sea (eastward instead of the predominantly westward circulation). The authors linked this to the loss of sea ice in the Barents Sea, anomalous warming over the region, and the intrusion of low-pressure cyclones along the eastern Arctic. In this commentary we discuss the significance of this observation, the challenges associated with understanding these possible linkages, and some of the alternative hypotheses surrounding the impacts of winter Arctic sea ice loss.

A Transgenic Mouse Model of Poliomyelitis.

PubMed

Koike, Satoshi; Nagata, Noriyo

2016-01-01

Transgenic mice (tg mice) that express the human poliovirus receptor (PVR), CD155, are susceptible to poliovirus and develop a neurological disease that resembles human poliomyelitis. Assessment of the neurovirulence levels of poliovirus strains, including mutant viruses produced by reverse genetics, circulating vaccine-derived poliovirus, and vaccine candidates, is useful for basic research of poliovirus pathogenicity, the surveillance of circulating polioviruses, and the quality control of oral live poliovirus vaccines, and does not require the use of monkeys. Furthermore, PVR-tg mice are useful for studying poliovirus tissue tropism and host immune responses. PVR-tg mice can be bred with mice deficient in the genes involved in viral pathogenicity. This report describes the methods used to analyze the pathogenicity and immune responses of poliovirus using the PVR-tg mouse model.

Soft shell clams Mya arenaria with disseminated neoplasia demonstrate reverse transcriptase activity

USGS Publications Warehouse

House, M.L.; Kim, C.H.; Reno, P.W.

1998-01-01

Disseminated neoplasia (DN), a proliferative cell disorder of the circulatory system of bivalves, was first reported in oysters in 1969. Since that time, the disease has been determined to be transmissible through water-borne exposure, but the etiological agent has not been unequivocally identified. In order to determine if a viral agent, possibly a retrovirus, could be the causative agent of DN, transmission experiments were performed, using both a cell-free filtrate and a sucrose gradient-purified preparation of a cell-free filtrate of DN positive materials. Additionally, a PCR-enhanced reverse transcriptase assay was used to determine if reverse transcriptase was present in tissues or hemolymph from DN positive soft shell clams Mya arenaria. DN was transmitted to healthy clams by injection with whole DN cells, but not with cell-free flitrates prepared from either tissues from DN positive clams, or DN cells. The cell-free preparations from DN-positive tissues and hemolymph having high levels of DN cells in circulation exhibited positive reactions in the PCR-enhanced reverse transcriptase assay. Cell-free preparations of hemolymph from clams having low levels of DN (<0.1% of cells abnormal), hemocytes from normal soft shell clams, and normal soft shell clam tissues did not produce a positive reaction in the PCR enhanced reverse transcriptase assay.

75 FR 54912 - Drill Pipe and Drill Collars From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

...)] Drill Pipe and Drill Collars From China AGENCY: United States International Trade Commission. ACTION... retarded, by reason of subsidized and less-than-fair-value imports from China of drill pipe and drill... defined the subject merchandise as steel drill pipe, and steel drill collars, whether or not conforming to...

30 CFR 56.7009 - Drill helpers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drill helpers. 56.7009 Section 56.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7009 Drill helpers. If a drill helper assists the drill operator during movement of a drill...

30 CFR 56.7009 - Drill helpers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drill helpers. 56.7009 Section 56.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7009 Drill helpers. If a drill helper assists the drill operator during movement of a drill...

30 CFR 56.7009 - Drill helpers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drill helpers. 56.7009 Section 56.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7009 Drill helpers. If a drill helper assists the drill operator during movement of a drill...

30 CFR 56.7009 - Drill helpers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drill helpers. 56.7009 Section 56.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7009 Drill helpers. If a drill helper assists the drill operator during movement of a drill...

30 CFR 56.7009 - Drill helpers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill helpers. 56.7009 Section 56.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7009 Drill helpers. If a drill helper assists the drill operator during movement of a drill...

Compact drilling and sample system

NASA Technical Reports Server (NTRS)

Gillis-Smith, Greg R.; Petercsak, Doug

1998-01-01

The Compact Drilling and Sample System (CDSS) was developed to drill into terrestrial, cometary, and asteroid material in a cryogenic, vacuum environment in order to acquire subsurface samples. Although drills were used by the Apollo astronauts some 20 years ago, this drill is a fraction of the mass and power and operates completely autonomously, able to drill, acquire, transport, dock, and release sample containers in science instruments. The CDSS has incorporated into its control system the ability to gather science data about the material being drilled by measuring drilling rate per force applied and torque. This drill will be able to optimize rotation and thrust in order to achieve the highest drilling rate possible in any given sample. The drill can be commanded to drill at a specified force, so that force imparted on the rover or lander is limited. This paper will discuss the cryo dc brush motors, carbide gears, cryogenic lubrication, quick-release interchangeable sampling drill bits, percussion drilling and the control system developed to achieve autonomous, cryogenic, vacuum, lightweight drilling.

Decadal variability of tropical tropopause temperature and its relationship to the Pacific Decadal Oscillation.

PubMed

Wang, Wuke; Matthes, Katja; Omrani, Nour-Eddine; Latif, Mojib

2016-07-12

Tropopause temperatures (TPTs) control the amount of stratospheric water vapour, which influences chemistry, radiation and circulation in the stratosphere, and is also an important driver of surface climate. Decadal variability and long-term trends in tropical TPTs as well as stratospheric water vapour are largely unknown. Here, we present for the first time evidence, from reanalysis and state-of-the-art climate model simulations, of a link between decadal variability in tropical TPTs and the Pacific Decadal Oscillation (PDO). The negative phase of the PDO is associated with anomalously cold sea surface temperatures (SSTs) in the tropical east and central Pacific, which enhance the zonal SST gradient across the equatorial Pacific. The latter drives a stronger Walker Circulation and a weaker Hadley Circulation, which leads to less convection and subsequently a warmer tropopause over the central equatorial Pacific. Over the North Pacific, positive sea level pressure anomalies occur, which damp vertical wave propagation into the stratosphere. This in turn slows the Brewer-Dobson circulation, and hence warms the tropical tropopause, enabling more water vapour to enter the stratosphere. The reverse chain of events holds for the positive phase of the PDO. Such ocean-troposphere-stratosphere interactions may provide an important feedback on the Earth's global surface temperature.

Scaling and Numerical Model Evaluation of Snow-Cover Effects on the Generation and Modification of Daytime Mesoscale Circulations.

NASA Astrophysics Data System (ADS)

Segal, M.; Garratt, J. R.; Pielke, R. A.; Ye, Z.

1991-04-01

Consideration of the sensible heat flux characteristics over a snow surface suggests a significant diminution in the magnitude of the flux, compared to that over a snow-free surface under the same environmental conditions. Consequently, the existence of snow-covered mesoscale areas adjacent to snow-free areas produces horizontal thermal gradients in the lower atmosphere during the daytime, possibly resulting in a `snow breeze.' In addition, suppression of the daytime thermally induced upslope flow over snow-covered slopes is likely to occur. The present paper provides scaling and modeling evaluations of these situations, with quantification of the generated and modified circulations. These evaluations suggest that under ideal situations involved with uniform snow cover over large areas, particularly in late winter and early spring, a noticeable `snow breeze' is likely to develop. Additionally: suppression of the daytime thermally induced upslope flow is significant and may even result in a daytime drainage flow. The effects of bare ground patchiness in the snow cover on these circulations are also explored, both for flat terrain and slope-flow situations. A patchiness fraction greater than 0.5 is found to result in a noticeably reduced snow-breeze circulation, while a patchiness fraction of only 0.1 caused the simulated daytime drainage flow over slopes to he reversed.

Decadal variability of tropical tropopause temperature and its relationship to the Pacific Decadal Oscillation

PubMed Central

Wang, Wuke; Matthes, Katja; Omrani, Nour-Eddine; Latif, Mojib

2016-01-01

Tropopause temperatures (TPTs) control the amount of stratospheric water vapour, which influences chemistry, radiation and circulation in the stratosphere, and is also an important driver of surface climate. Decadal variability and long-term trends in tropical TPTs as well as stratospheric water vapour are largely unknown. Here, we present for the first time evidence, from reanalysis and state-of-the-art climate model simulations, of a link between decadal variability in tropical TPTs and the Pacific Decadal Oscillation (PDO). The negative phase of the PDO is associated with anomalously cold sea surface temperatures (SSTs) in the tropical east and central Pacific, which enhance the zonal SST gradient across the equatorial Pacific. The latter drives a stronger Walker Circulation and a weaker Hadley Circulation, which leads to less convection and subsequently a warmer tropopause over the central equatorial Pacific. Over the North Pacific, positive sea level pressure anomalies occur, which damp vertical wave propagation into the stratosphere. This in turn slows the Brewer-Dobson circulation, and hence warms the tropical tropopause, enabling more water vapour to enter the stratosphere. The reverse chain of events holds for the positive phase of the PDO. Such ocean-troposphere-stratosphere interactions may provide an important feedback on the Earth’s global surface temperature. PMID:27404090

Influence of forced internal air circulation on airflow distribution and heat transfer in a gas double-dynamic solid-state fermentation bioreactor.

PubMed

Chen, Hongzhang; Qin, Lanzhi; Li, Hongqiang

2014-02-01

Internal air circulation affects the temperature field distribution in a gas double-dynamic solid-state fermentation bioreactor (GDSFB). To enhance heat transfer through strengthening internal air circulation in a GDSFB, we put an air distribution plate (ADP) into the bioreactor and studied the effects of forced internal air circulation on airflow, heat transfer, and cellulase activity of Trichoderma viride L3. Results showed that ADP could help form a steady and uniform airflow distribution, and with gas-guide tubes, air reversal was formed inside the bioreactor, thus resulting in a smaller temperature difference between medium and air by enhancing convective heat transfer inside the bioreactor. Using an ADP of 5.35 % aperture ratio caused a 1 °C decrease in the average temperature difference during the solid-state fermentation process of T. viride L3. Meanwhile, the cellulase activity of T. viride L3 increased by 13.5 %. The best heat-transfer effect was attained when using an ADP of 5.35 % aperture ratio and setting the fan power to 125 V (4.81 W) in the gas double-dynamic solid-state fermentation (GDSF) process. An option of suitable aperture ratio and fan power may be conducive to ADPs' industrial amplification.

Soy Protein Isolate As Fluid Loss Additive in Bentonite-Water-Based Drilling Fluids.

PubMed

Li, Mei-Chun; Wu, Qinglin; Song, Kunlin; Lee, Sunyoung; Jin, Chunde; Ren, Suxia; Lei, Tingzhou

2015-11-11

Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite-water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications.

Hydrothermal minerals and microstructures in the Silangkitang geothermal field along the Great Sumatran fault zone, Sumatra, Indonesia

USGS Publications Warehouse

Moore, Diane E.; Hickman, S.; Lockner, D.A.; Dobson, P.F.

2001-01-01

Detailed study of core samples of silicic tuff recovered from three geothermal wells along the strike-slip Great Sumatran fault zone near Silangkitang, North Sumatra, supports a model for enhanced hydrothermal circulation adjacent to this major plate-boundary fault. Two wells (A and C) were drilled nearly vertically ??1 km southwest of the eastern (i.e., the principal) fault trace, and the third, directional well (B) was drilled eastward from the site of well A to within ??100 m of the principal fault trace. The examined core samples come from depths of 1650-2120 m at measured well temperatures of 180-320 ??C. The samples collected near the principal fault trace have the highest temperatures, the largest amount of secondary pore space that correlates with high secondary permeability, and the most extensive hydrothermal mineral development. Secondary permeability and the degree of hydrothermal alteration decrease toward the southwestern margin of the fault zone. These features indicate episodic, localized flow of hot, possibly CO2-rich fluids within the fault zone. The microstructure populations identified in the core samples correlate to the subsidiary fault patterns typical of strike-slip faults. The geothermal reservoir appears to be centered on the fault zone, with the principal fault strands and adjoining, highly fractured and hydrothermally altered rock serving as the main conduits for vertical fluid flow and advective heat transport from deeper magmatic sources.

The eastern arm of the Midcontinent Rift: Progress and problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinze, W.J.

1994-04-01

The extent and nature of the Midcontinent Rift System (MCR) was initially determined by potential-field mapping and extrapolation of geologic information from the Lake Superior region. Early interpretation suggested a rift origin which is well supported by deep crustal reflection seismic data and isotopic evidence from the related volcanic rocks that became available during the past decade. A rift origin of the eastern arm of the MCR was corroborated by sub-Phanerozoic drilling into the clastic sediment and volcanic rocks in the McClure-Sparks drill hole located on a massive anticlinal feature in the Precambrian rocks mapped by seismic reflection data. Subsequentmore » seismic profiling further detailed the character of the rift. However, these studies also indicate that the eastern arm is unlike the western, e.g., adjacent clastic rock basins are absent, late-stage compressional features are present, but definite evidence for high-angle reverse faulting is missing, and volcanic basins are not continuous. The termination of this arm of the rift also remains problematic. There is no direct evidence of the rift SE of the McClure-Sparks hole in central Michigan. Geophysical anomalies and deep drilling in the Howell anticline region suggest that the 1,100 Ma old rift is covered by Grenville-age thrusts. If the rift extends farther to the SE, its nature must have been altered by the Grenville orogeny. The hypothesized extension across Ohio east of the Grenville Front is unsupported by seismic reflection profiling and anomaly modeling. Grabens identified at the basement surface in Ohio and to the south are of unknown age, but appear to be more clearly related to late-stage Grenville activity and/or continuation of Eocambrian rifts of the Mississippi Embayment.« less

Criterion validity and accuracy of global positioning satellite and data logging devices for wheelchair tennis court movement

PubMed Central

Sindall, Paul; Lenton, John P.; Whytock, Katie; Tolfrey, Keith; Oyster, Michelle L.; Cooper, Rory A.; Goosey-Tolfrey, Victoria L.

2013-01-01

Purpose To compare the criterion validity and accuracy of a 1 Hz non-differential global positioning system (GPS) and data logger device (DL) for the measurement of wheelchair tennis court movement variables. Methods Initial validation of the DL device was performed. GPS and DL were fitted to the wheelchair and used to record distance (m) and speed (m/second) during (a) tennis field (b) linear track, and (c) match-play test scenarios. Fifteen participants were monitored at the Wheelchair British Tennis Open. Results Data logging validation showed underestimations for distance in right (DLR) and left (DLL) logging devices at speeds >2.5 m/second. In tennis-field tests, GPS underestimated distance in five drills. DLL was lower than both (a) criterion and (b) DLR in drills moving forward. Reversing drill direction showed that DLR was lower than (a) criterion and (b) DLL. GPS values for distance and average speed for match play were significantly lower than equivalent values obtained by DL (distance: 2816 (844) vs. 3952 (1109) m, P = 0.0001; average speed: 0.7 (0.2) vs. 1.0 (0.2) m/second, P = 0.0001). Higher peak speeds were observed in DL (3.4 (0.4) vs. 3.1 (0.5) m/second, P = 0.004) during tennis match play. Conclusions Sampling frequencies of 1 Hz are too low to accurately measure distance and speed during wheelchair tennis. GPS units with a higher sampling rate should be advocated in further studies. Modifications to existing DL devices may be required to increase measurement precision. Further research into the validity of movement devices during match play will further inform the demands and movement patterns associated with wheelchair tennis. PMID:23820154

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

NASA Astrophysics Data System (ADS)

Naidu, M. C. A.; Nolakha, Dinesh; Saharkar, B. S.; Kavani, K. M.; Patel, D. R.

2012-11-01

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of "Open loop, auto reversing liquid nitrogen based thermal system". System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

Micro thermal diode with glass thermal insulation structure embedded in a vapor chamber

NASA Astrophysics Data System (ADS)

Tsukamoto, Takashiro; Hirayanagi, Takashi; Tanaka, Shuji

2017-04-01

This paper reports a micro thermal diode based on one-way working fluid circulation driven by surface tension force. In forward mode, working fluid evaporates and condenses at a heated and cooled area, respectively, and the condensed liquid returns to the evaporation area due to the wettability difference. By this vapor-liquid phase change mechanism, the overall heat transfer coefficient becomes high. On the other hand, in reverse mode, no continuous evaporation-condensation cycle exists. The conductive heat loss in reverse mode was minimized by an embedded glass thermal isolation structure, which makes overall heat transfer coefficient low. The test device was made by a standard MEMS process combined with glass reflow and gold bump sealing. The overall heat transfer coefficients of 13 300 \\text{W}~{{\\text{m}}-2}~\\text{K} for forward mode and 4790 \\text{W}~{{\\text{m}}-2}~\\text{K} for reverse mode were measured. The performance index of the micro thermal diode was about 2.8.

HIV type 1 genotypic variation in an antiretroviral treatment-naive population in southern India.

PubMed

Balakrishnan, Pachamuthu; Kumarasamy, Nagalingeswaran; Kantor, Rami; Solomon, Suniti; Vidya, Sundararajan; Mayer, Kenneth H; Newstein, Michael; Thyagarajan, Sadras P; Katzenstein, David; Ramratnam, Bharat

2005-04-01

Most studies of HIV-1 drug resistance have examined subtype B viruses; fewer data are available from developing countries, where non-B subtypes predominate. We determined the prevalence of mutations at protease and reverse transcriptase drug resistance positions in antiretroviral drug-naive individuals in southern India. The pol region of the genome was amplified from plasma HIV-1 RNA in 50 patients. All sequences clustered with HIV-1 subtype C. All patients had at least one protease and/or RT mutation at a known subtype B drug resistance position. Twenty percent of patients had mutations at major protease inhibitor resistance positions and 100% had mutations at minor protease inhibitor resistance positions. Six percent and 14% of patients had mutations at nucleoside reverse transcriptase inhibitor and/or nonnucleoside reverse transcriptase inhibitor resistance positions, respectively. Larger scale studies need to be undertaken to better define the genotypic variation of circulating Indian subtype C viruses and their potential impact on drug susceptibility and clinical outcome in treated individuals.

Two-way shape memory behavior of semi-crystalline elastomer under stress-free condition

NASA Astrophysics Data System (ADS)

Qian, Chen; Dong, Yubing; Zhu, Yaofeng; Fu, Yaqin

2016-08-01

Semi-crystalline shape memory polymers exhibit two-way shape memory effect (2W-SME) under constant stresses through crystallization-induced elongation upon cooling and melting-induced constriction upon heating. The applied constant stress influenced the prediction and usability of 2W-SME in practical applications without any external force. Here the reversible shape transition in EVA-shaped memory polymer was quantitative analyzed under a suitable temperature range and external stress-free condition. The fraction of reversible strain increased with increasing upper temperature (T high) within the temperature range and reached the maximum value of 13.62% at 70 °C. However, reversible strain transition was almost lost when T high exceeded 80 °C because of complete melting of crystalline scaffold, known as the latent recrystallization template. The non-isothermal annealing of EVA 2W-SMP under changing circulating temperatures was confirmed. Moreover, the orientation of crystallization was retained at high temperatures. These findings may contribute to design an appropriate shape memory protocol based on application-specific requirements.

Soluble serum interleukin 2 receptor levels in leprosy patients

PubMed Central

Tung, K. S. K.; Umland, Edith; Matzner, P.; Nelson, K.; Schauf, Victoria; Rubin, L.; Wagner, D.; Scollard, D.; Vithayasai, Prakong; Vithayasai, Vicharn; Worobec, Sophie; Smith, T.; Suriyanond, Vinai

1987-01-01

Soluble interleukin 2 receptors (IL-2R) in sera of leprosy patients from Chiang Mai, Thailand, were quantified with a solid phase enzyme immunoassay using two monoclonal antibodies to the IL-2R. The IL-2R levels of untreated lepromatous, borderline lepromatous or midborderline patients and treated lepromatous and borderline lepromatous or treated borderline tuberculoid and tuberculoid patients were comparable to those of the Thai household or nonhousehold contacts; and they were significantly higher than the levels of USA control subjects. In contrast, IL-2R of untreated tuberculoid or borderline tuberculoid patients were significantly reduced. Patients with ongoing reversal reaction had very high circulating IL-2R, the levels of which correlated with fever and extent of skin lesions. Although erythrema nodosum leprosum patients also had elevated IL-2R levels, they were significantly below those of patients with reversal reaction. When treated with corticosteroid, precipitous reduction of IL-2R was noted in all patients with reversal reaction but not in patients with erythema nodosum leprosum. PMID:3115652

Pressure-gradient-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system

USGS Publications Warehouse

Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.

2011-01-01

The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the pressure field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore pressure gradient associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. Pressure-gradient- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.

Circulating rotavirus-specific T cells have a poor functional profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parra, Miguel; Herrera, Daniel; Jácome, María Fernanda

Frequencies of circulating T cells producing IFN-γ, TNF-α, and IL-2, and percentages of T cells proliferating after stimulation with rotavirus (RV), tetanus toxoid, and influenza were evaluated in PBMC derived from healthy adults and children. In addition, the potential anergic state of RV-specific T cells was analyzed by stimulation of PBMC with RV antigen in the presence of three anergy inhibitors (rIL-2, rIL-12, or DGKα-i). The quality and magnitude of RV-T cell responses were significantly lower than those of tetanus toxoid and influenza antigens. RV-CD4 T cell response was enriched in monofunctional IFN-γ{sup +} cells, while influenza-CD4 and tetanus toxoid-CD4more » T cell responses were enriched in multifunctional T cells. Moreover, rIL-2 – unlike rIL-12 or DGKα-i – increased the frequencies of RV-CD4 TNF-α{sup +}, CD4 IFN-γ{sup +}, and CD8 IFN-γ{sup +} cells. Thus, circulating RV-T cells seem to have a relatively poor functional profile that may be partially reversed in vitro by the addition of rIL-2. - Highlights: • The quality and magnitude of circulating RV-T cell responses are relatively poor. • Circulating RV-CD4 T cells are enriched in monofunctional IFN-γ+ cells. • Treatment with rIL-2 increased the frequencies of cytokine secreting RV-T cells.« less

Contrast-Induced Nephropathy Is Less Common in Patients with Good Coronary Collateral Circulation.

PubMed

Avci, Eyup; Yildirim, Tarik; Kadi, Hasan

2017-10-01

Contrast-induced nephropathy (CIN) is a typically reversible type of acute renal failure that develops after exposure to contrast agents; underlying endothelial dysfunction is thought to be an important risk factor for CIN. Although the mechanism of coronary collateral circulation (CCC) is not fully understood, a pivotal role of the endothelium has been reported in many studies. The aim of this study was to investigate whether there is a relationship between CCC and CIN. Patients with at least one occluded major coronary artery and blood creatinine analyses performed before and on the second day after angiography were included in the study. CIN was defined as a 25% or greater elevation of creatinine on the second day after exposure to the contrast agent. Collateral grading was performed according to the Rentrop classification. Patients were grouped according to whether they developed CIN or not, i.e., CIN(-) and CIN(+) group. A total of 214 patients who met the inclusion criteria were included in the study. CIN was diagnosed in 43 patients (20.1%) in the study population. Good CCC was identified in 112 patients (65.5%) in the CIN(-) group, whereas it was identified in 13 patients (30.2%) in the CIN(+) group. In the CIN(-) group, good CCC was significantly more frequent ( p < 0.001). Furthermore, collateral circulation was an independent predictor of CIN. Good collateral circulation was associated with a lower frequency of CIN, and poor collateral circulation was an independent predictor of CIN.

Kinematics and aerodynamics of avian upstrokes during slow flight.

PubMed

Crandell, Kristen E; Tobalske, Bret W

2015-08-01

Slow flight is extremely energetically costly per unit time, yet highly important for takeoff and survival. However, at slow speeds it is presently thought that most birds do not produce beneficial aerodynamic forces during the entire wingbeat: instead they fold or flex their wings during upstroke, prompting the long-standing prediction that the upstroke produces trivial forces. There is increasing evidence that the upstroke contributes to force production, but the aerodynamic and kinematic mechanisms remain unknown. Here, we examined the wingbeat cycle of two species: the diamond dove (Geopelia cuneata) and zebra finch (Taeniopygia guttata), which exhibit different upstroke styles - a wingtip-reversal and flexed-wing upstroke, respectively. We used a combination of particle image velocimetry and near-wake streamline measures alongside detailed 3D kinematics. We show that during the middle of the wingtip-reversal upstroke, the hand-wing has a high angular velocity (15.3±0.8 deg ms(-1)) and translational speed (8.4±0.6 m s(-1)). The flexed-wing upstroke, in contrast, has low wingtip speed during mid-upstroke. Instead, later in the stroke cycle, during the transition from upstroke to downstroke, it exhibits higher angular velocities (45.5±13.8 deg ms(-1)) and translational speeds (11.0±1.9 m s(-1)). Aerodynamically, the wingtip-reversal upstroke imparts momentum to the wake, with entrained air shed backward (visible as circulation of 14.4±0.09 m(2) s(-1)). In contrast, the flexed-wing upstroke imparts minimal momentum. Clap and peel in the dove enhances the time course for circulation production on the wings, and provides new evidence of convergent evolution on time-varying aerodynamic mechanisms during flapping in insects and birds. © 2015. Published by The Company of Biologists Ltd.

Generation of a mouse model with a reversible hypomorphic cytochrome P450 reductase gene: utility for tissue-specific rescue of the reductase expression, and insights from a resultant mouse model with global suppression of P450 reductase expression in extrahepatic tissues.

PubMed

Wei, Yuan; Zhou, Xin; Fang, Cheng; Li, Lei; Kluetzman, Kerri; Yang, Weizhu; Zhang, Qing-Yu; Ding, Xinxin

2010-07-01

A mouse model termed Cpr-low (CL) was recently generated, in which the expression of the cytochrome P450 reductase (Cpr) gene was globally down-regulated. The decreased CPR expression was accompanied by phenotypical changes, including reduced embryonic survival, decreases in circulating cholesterol, increases in hepatic P450 expression, and female infertility (accompanied by elevated serum testosterone and progesterone levels). In the present study, a complementary mouse model [named reversible-CL (r-CL)] was generated, in which the reduced CPR expression can be reversed in an organ-specific fashion. The neo cassette, which was inserted into the last Cpr intron in r-CL mice, can be deleted by Cre recombinase, thus returning the structure of the Cpr gene (and hence CPR expression) to normal in Cre-expressing cells. All previously identified phenotypes of the CL mice were preserved in the r-CL mice. As a first application of the r-CL model, we have generated an extrahepatic-CL (xh-CL) mouse for testing of the functions of CPR-dependent enzymes in all extrahepatic tissues. The xh-CL mice, generated by mating of r-CL mice with albumin-Cre mice, had normal CPR expression in hepatocytes but down-regulated CPR expression elsewhere. They were indistinguishable from wild-type mice in body and liver weights, circulating cholesterol levels, and hepatic microsomal P450 expression and activities; however, they still showed elevated serum testosterone and progesterone levels and sterility in females. Embryonic lethality was prevented in males, but apparently not in females, indicating a critical role for fetal hepatic CPR-dependent enzymes in embryonic development, at least in males.

A Novel Well Drill Assisted with High-Frequency Vibration Using the Bending Mode

PubMed Central

Qi, Xinda; Chen, Weishan; Tang, Xintian; Shi, Shengjun

2018-01-01

It is important for companies to increase the efficiency of drilling as well as prolong the lifetime of the drilling tool. Since some previous investigations indicated that a superposition of well drilling with an additional vibration increases the drilling efficiency, this paper introduces a novel well drill which is assisted with additional vibrations by means of piezoelectric sandwich bending vibration transducer. The proposed drill uses bending vibrations in two different directions to from an elliptical trajectory movement, which can help the drill to break the surface of hard material more efficiently and clean away the lithic fragments more easily. The proposed well drill with bending vibration transducer is designed to have a resonance frequency of the first bending vibration mode of about 1779 Hz. The motion equation of the particle on the edge of the drill bit is developed and analyzed. The vibration trajectory of the particle on the edge of the drill bit is calculated by using finite element method. A prototype of the proposed drill using bending vibrations is fabricated and tested to verify the aim of drilling efficiency increase. The feed speed of the vibration assisted drilling is tested to be about 0.296 mm/s when the excitation voltage of the transducer is 300 V, while this speed decreases to about 0.195 mm/s when no vibration is added. This comparison shows that the feed speed of the vibration assisted drilling is about 52% higher than that of the normal drilling, which means the proposed drill has a better efficiency and it is important to consider vibration superimposition in well drilling. In addition, the surface of the drill hole gained by the vibration assisted drilling is smoother than that of the normal drilling, which makes the clearance easier. PMID:29641481

Design and performance study of an orthopaedic surgery robotized module for automatic bone drilling.

PubMed

Boiadjiev, George; Kastelov, Rumen; Boiadjiev, Tony; Kotev, Vladimir; Delchev, Kamen; Zagurski, Kazimir; Vitkov, Vladimir

2013-12-01

Many orthopaedic operations involve drilling and tapping before the insertion of screws into a bone. This drilling is usually performed manually, thus introducing many problems. These include attaining a specific drilling accuracy, preventing blood vessels from breaking, and minimizing drill oscillations that would widen the hole. Bone overheating is the most important problem. To avoid such problems and reduce the subjective factor, automated drilling is recommended. Because numerous parameters influence the drilling process, this study examined some experimental methods. These concerned the experimental identification of technical drilling parameters, including the bone resistance force and temperature in the drilling process. During the drilling process, the following parameters were monitored: time, linear velocity, angular velocity, resistance force, penetration depth, and temperature. Specific drilling effects were revealed during the experiments. The accuracy was improved at the starting point of the drilling, and the error for the entire process was less than 0.2 mm. The temperature deviations were kept within tolerable limits. The results of various experiments with different drilling velocities, drill bit diameters, and penetration depths are presented in tables, as well as the curves of the resistance force and temperature with respect to time. Real-time digital indications of the progress of the drilling process are shown. Automatic bone drilling could entirely solve the problems that usually arise during manual drilling. An experimental setup was designed to identify bone drilling parameters such as the resistance force arising from variable bone density, appropriate mechanical drilling torque, linear speed of the drill, and electromechanical characteristics of the motors, drives, and corresponding controllers. Automatic drilling guarantees greater safety for the patient. Moreover, the robot presented is user-friendly because it is simple to set robot tasks, and process data are collected in real time. Copyright © 2013 John Wiley & Sons, Ltd.

In-vitro analysis of forces in conventional and ultrasonically assisted drilling of bone.

PubMed

Alam, K; Hassan, Edris; Imran, Syed Husain; Khan, Mushtaq

2016-05-12

Drilling of bone is widely performed in orthopaedics for repair and reconstruction of bone. Current paper is focused on the efforts to minimize force generation during the drilling process. Ultrasonically Assisted Drilling (UAD) is a possible option to replace Conventional Drilling (CD) in bone surgical procedures. The purpose of this study was to investigate and analyze the effect of drilling parameters and ultrasonic parameters on the level of drilling thrust force in the presence of water irrigation. Drilling tests were performed on young bovine femoral bone using different parameters such as spindle speeds, feed rates, coolant flow rates, frequency and amplitudes of vibrations. The drilling force was significantly dropped with increase in drill rotation speed in both types of drilling. Increase in feed rate was more influential in raising the drilling force in CD compared to UAD. The force was significantly dropped when ultrasonic vibrations up to 10 kHz were imposed on the drill. The drill force was found to be unaffected by the range of amplitudes and the amount of water supplied to the drilling region in UAD. Low frequency vibrations with irrigation can be successfully used for safe and efficient drilling in bone.

Preliminary biological sampling of GT3 and BT1 cores and the microbial community dynamics of existing subsurface wells

NASA Astrophysics Data System (ADS)

Kraus, E. A.; Stamps, B. W.; Rempfert, K. R.; Ellison, E. T.; Nothaft, D. B.; Boyd, E. S.; Templeton, A. S.; Spear, J. R.

2017-12-01

Subsurface microbial life is poorly understood but potentially very important to the search for life on other planets as well as increasing our understanding of Earth's geobiological processes. Fluids and rocks of actively serpentinizing subsurface environments are a recent target of biological study due to their apparent ubiquity across the solar system. Areas of serpentinization can contain high concentrations of molecular hydrogen, H2, that can serve as the dominant fuel source for subsurface microbiota. Working with the Oman Drilling Project, DNA and RNA were extracted from fluids of seven alkaline wells and two rock cores from drill sites GT3 and BT1 within the Samail ophiolite. DNA and cDNA (produced via reverse transcription from the recovered RNA) were sequenced using universal primers to identify microbial life across all three domains. Alkaline subsurface fluids support a microbial community that changes with pH and host-rock type. In peridotite with pH values of >11, wells NSHQ 14 and WAB 71 have high relative abundances of Meiothermus, Methanobacterium, the family Nitrospiraceae, and multiple types of the class Dehalococcoidia. While also hosted in peridotite but at pH 8.5, wells WAB 104 and 105 have a distinct, more diverse microbial community. This increased variance in community make-up is seen in wells that sit near/at the contact of gabbro and peridotite formations as well. Core results indicate both sampled rock types host a very low biomass environment subject to multiple sources of contamination during the drilling process. Suggestions for contaminant reduction, such as having core handlers wear nitrile gloves and flame-sterilizing the outer surfaces of core rounds for biological sampling, would have minimal impact to overall ODP coreflow and maximize the ability to better understand in situ microbiota in this low-biomass serpentinizing subsurface environment. While DNA extraction was successful with gram amounts of crushed rock, much can be done to improve yields and reduce contamination sources for Phase II drilling.

The Pleistocene evolution of the East Antarctic Ice Sheet in the Prydz bay region: Stable isotopic evidence from ODP Site 1167

USGS Publications Warehouse

Theissen, K.M.; Dunbar, R.B.; Cooper, A. K.; Mucciarone, D.A.; Hoffmann, D.

2003-01-01

Ocean Drilling Program Leg 188, Prydz Bay, East Antarctica is part of a larger initiative to explore the Cenozoic history of the Antarctic Ice Sheet through direct drilling and sampling of the continental margins. In this paper, we present stable isotopic results from Ocean Drilling Program (ODP) Site 1167 located on the Prydz Channel Trough Mouth Fan (TMF), the first Antarctic TMF to be drilled. The foraminifer-based ??18O record is interpreted along with sedimentary and downhole logging evidence to reconstruct the Quaternary glacial history of Prydz Bay and the adjacent Lambert Glacier Amery Ice Shelf System (LGAISS). We report an electron spin resonance age date of 36. 9 ?? 3.3 ka at 0.45 m below sea floor and correlate suspected glacial-interglacial cycles with the global isotopic stratigraphy to improve the chronology for Site 1167. The ??18O record based on planktonic (Neogloboquadrina pachyderma (s.)) and limited benthic results (Globocassidulina crassa), indicates a trend of ice sheet expansion that was interrupted by a period of reduced ice volume and possibly warmer conditions during the early-mid-Pleistocene (0.9-1.38 Ma). An increase in ?? 18O values after ??? 900 ka appears to coincide with the mid-Pleistocene climate transition and the expansion of the northern hemisphere ice sheet. The ??18O record in the upper 50 m of the stratigraphic section indicates as few as three glacial-interglacial cycles, tentatively assigned as marine isotopic stages (MIS) 16-21, are preserved since the Brunhes/Matuyama paleomagnetic reversal (780 ka). This suggests that there is a large unconformity near the top of the section and/or that there may have been few extreme advances of the ice sheet since the mid-Pleistocene climate transition resulting in lowered sedimentation rates on the Prydz Channel TMF. The stable isotopic record from Site 1167 is one of the few available from the area south of the Antarctic Polar Front that has been linked with the global isotopic stratigraphy. Our results suggest the potential for the recovery of useful stable isotopic records in other TMFs. ?? 2003 Elsevier B.V. All rights reserved.

Planning for the Paleomagnetic Investigations of Returned Samples from Mars

NASA Astrophysics Data System (ADS)

Weiss, B. P.; Beaty, D. W.; McSween, H. Y., Jr.; Czaja, A. D.; Goreva, Y.; Hausrath, E.; Herd, C. D. K.; Humayun, M.; McCubbin, F. M.; McLennan, S. M.; Pratt, L. M.; Sephton, M. A.; Steele, A.; Hays, L. E.; Meyer, M. A.

2016-12-01

The red planet is a magnetic planet. Mars' iron-rich surface is strongly magnetized, likely dating back to the Noachian period when the surface may have been habitable. Paleomagnetic measurements of returned samples could transform our understanding of the Martian dynamo and its connection to climatic and planetary thermal evolution. Because the original orientations of Martian meteorites are unknown, all Mars paleomagnetic studies to date have only been able to measure the paleointensity of the Martian field. Paleomagnetic studies from returned Martian bedrock samples would provide unprecedented geologic context and the first paleodirectional information on Martian fields. The Mars 2020 rover mission seeks to accomplish the first leg by preparing for the potential return of 31 1 cm-diameter cores of Martian rocks. The Returned Sample Science Board (RSSB) has been tasked to advise the Mars 2020 mission in how to best select and preserve samples optimized for paleomagnetic measurements. A recent community-based study (Weiss et al., 2014) produced a ranked list of key paleomagnetism science objectives, which included: 1) Determine the intensity of the Martian dynamo 2) Characterize the dynamo reversal frequency with magnetostratigraphy 3) Constrain the effects of heating and aqueous alteration on the samples 4) Constrain the history of Martian tectonics Guided by these objectives, the RSSB has proposed four key sample quality criteria to the Mars 2020 mission: (a) no exposure to fields >200 mT, (b) no exposure to temperatures >100 °C, (c) no exposure to pressures >0.1 GPa, and (d) acquisition of samples that are absolutely oriented with respect to bedrock with a half-cone uncertainty of <5°. Our measurements of a Mars 2020 prototype drill have found that criteria (a-c) should be met by the drilling process. Furthermore, the core plate strike and dip will be measured to better than 5° for intact drill cores; we are working with the mission to establish ways to determine the core's angular orientation with respect to rotation around the drill hole axis. The next stage of our work is to establish whether and how these sample criteria would be maintained throughout the potential downstream missions that would return the samples to Earth.

South African Climates: Highlights From International Ocean Discovery Program Expedition 361

NASA Astrophysics Data System (ADS)

Hemming, S. R.; Hall, I. R.; LeVay, L.

2016-12-01

International Ocean Discovery Program Expedition 361 drilled six sites on the southeast African margin and in the Indian-Atlantic ocean gateway, southwest Indian Ocean, from 30 January to 31 March 2016. In total, 5175 m of core was recovered, with an average recovery of 102%, during 29.7 days of on-site operations. The sites, situated in the Mozambique Channel, at locations directly influenced by discharge from the Zambezi and Limpopo River catchments, the Natal Valley, the Agulhas Plateau, and the Cape Basin were targeted to reconstruct the history of the Greater Agulhas Current System over the past 5 Ma. The Agulhas Current transports 70 Sv of warm and saline surface waters from the tropical Indian Ocean along the East African margin to the tip of Africa. Exchanges of heat and moisture with the atmosphere influence southern African rainfall patterns. Recent ocean model and paleoceanographic data further point at a potential role of the Agulhas Current in controlling the strength and mode of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Pleistocene. The main objectives of the expedition were to document the oceanographic properties of the Agulhas Current through tectonic and climatic changes during the Plio-Pleistocene, to determine the dynamics of the Indian-Atlantic gateway circulation during this time, to examine the connection of the Agulhas leakage and AMOC, to address the influence of the Agulhas Current on African terrestrial climates and potential links to Human evolution. Additionally, the Expedition set out to fulfill the needs of the Ancillary Project Letter, consisting of high-resolution interstitial water samples that will, and to constrain the temperature and salinity profiles of the ocean during the Last Glacial Maximum. Here we highlight some of the expedition successes and show how it has made major strides toward fulfilling each of these objectives. The recovered sequences allowed complete spliced stratigraphic sections to be generated that span the interval of 0 to between 0.2 and 7 Ma. These sediments provide an exceptional opportunity to generate decadal to millennial-scale climatic records that will resolve key paleoceanographic and paleoclimatic questions from a region poorly represented in the database of scientific drill sites.

Changing sediment physical properties at the Agulhas Plateau (IODP Site U1475): indications for the long-term variability of deepwater circulation over the last 7 Ma

NASA Astrophysics Data System (ADS)

Gruetzner, Jens; Lathika, Nambiyathodi; Jimenez Espejo, Francisco J.; Uenzelmann-Neben, Gabriele

2017-04-01

The gateway south of South Africa constitutes an integral inter-ocean link in the global thermohaline circulation (THC) since it allows the exchange of shallow- and deepwater masses between the Indian and the Atlantic. Thus understanding past variations of this current system is important for improving our knowledge of the global climate. The long-term changes in deepwater flow in the Atlantic-Indian gateway during the Cenozoic have been initially studied using reflection seismic profiles. But in many cases the seismic stratigraphy is poorly constrained and not further resolved within the time period from the late Miocene to present. In particular, there are limited Pliocene records that can be used to investigate the influence of climatic (e.g. Antartic ice volume) and tectonic (e.g. closure of the central American seaway) on the deep-water variability. Here we focus on the bottom water flow around the Agulhas Plateau, a location proximal to the entrance of North Atlantic Deep Water (NADW) to the Southern Ocean and South Indian Ocean. IODP Expedition 361 (SAFARI) Site U1475 was drilled in 2669 m water depth into a sediment drift that is deposited on the southwestern flank of Agulhas Plateau and comprises a complete stratigraphic section of the last 7 Ma. We present cleaned, edited, and spliced high-resolution data sets of sediment physical properties measured at Site U1475. Synthetic seismograms generated from the velocity and bulk density core scanning records allow a detailed correlation oft the drilling results with the Site survey seismic reflection profiles. Seismic reflectors at 3.75 and 3.87 s (two-way-traveltime) correspond to major increases in acoustic impedance at 110 and 216 meters below seafloor. Based on the preliminary shipboard biostratigraphic age model sediments at these depths have ages of 4.0 and 5.1 Ma, respectively. Furthermore spectral analyses of physical property records such as natural gamma radiation and colour reflectance reveal climate variability on orbital and suborbital timescales.

New insights into seismic faulting during the 2008 Mw7.9 Wenchuan earthquake

NASA Astrophysics Data System (ADS)

Li, H.; Wang, H.; Si, J.; Sun, Z.; Pei, J.; Lei, Z.; He, X.

2017-12-01

The WFSD project was implemented promptly after the 2008 Mw 7.9 Wenchuan earthquake. A series of research results on the seismogenic structure, fault deformation, sliding mechanism and fault healing have been obtained, which provide new insights into seismic faulting and mechanisms of the Wenchuan earthquake. The WFSD-1 and -2 drilling core profiles reveal that the Longmen Shan thrust belt is composed of multiple thrust sheets. The 2008 Wenchuan earthquake took place in such tectonic setting with strong horizontal shortening. The two ruptured faults have different deformation mechanisms. The Yingxiu-Beichuan fault (YBF) is a stick-slip fault characterized by fault gouge with high magnetic susceptibility, Guanxian-Anxian fault (GAF) with creeping features and characterized by fault gouge with low magnetic susceptibility. Two PSZs were found in WFSD-1 and -2 cores in the southern segment of YBF. The upper PSZ1 is a low-angle thrust fault characterized by coseisimc graphitization with an extremely low frictional coefficient. The lower PSZ2 is an oblique dextral-slip thrust fault characterized by frictional melt lubrication. In the northern segment of YBF, the PSZ in WFSD-4S cores shows a high-angle thrust feature with fresh melt as well. Therefore, the oblique dextral-slip thrust faulting with frictional melt lubrication is the main faulting of Wenchuan earthquake. Fresh melt with quenching texture was formed in Wenchuan earthquake implying vigorous fluid circulation occurred during the earthquake, which quenched high-temperature melt, hamper the aftermost fault slip and welding seismic fault. Therefore, fluids in the fault zone not only promotes fault weakening, but also suppress slipping in theWenchuan earthquake. The YBF has an extremely high hydraulic diffusivity (2.4×10-2 m2s-1), implying a vigorous fluid circulation in the Wenchuan fault zone. the permeability of YBF has reduced 70% after the shock, reflecting a rapid healing for the YBF. However, the water level has not changed in the WFSD-3 borehole drilled through GAF, indicating an unchanged permeability. These results are of great significance to understanding the seismogenic mechanisms and earthquake cycle for the Wenchuan earthquake.

Hydrothermal circulation at Mount St. Helens determined by self-potential measurements

USGS Publications Warehouse

Bedrosian, P.A.; Unsworth, M.J.; Johnston, M.J.S.

2007-01-01

The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential field was detected on the north face of the 1980-86 lava dome. This anomaly reaches a value of negative one volt on the lower flanks of the dome and reverses sign toward the dome summit. The anomaly pattern is believed to result from a combination of thermoelectric, electrokinetic, and fluid disruption effects within and surrounding the dome. Heat supplied from a cooling dacite magma very likely drives a shallow hydrothermal convection cell within the dome. The temporal stability of the SP field, low surface recharge rate, and magmatic component to fumarole condensates and thermal waters suggest the hydrothermal system is maintained by water vapor exsolved from the magma and modulated on short time scales by surface recharge. ?? 2006 Elsevier B.V. All rights reserved.

Genetic analysis of hepatitis A virus variants circulating among children presenting with acute diarrhea in Cameroon.

PubMed

Forbi, Joseph C; Agwale, Simon M; Ndip, Lucy M; Esona, Mathew D

2012-05-01

Molecular investigation was undertaken of circulating hepatitis A virus (HAV) associated with cases of acute diarrhea among children under 5 years of age in Kumba-Cameroon. Reverse transcription PCR, sequencing, and phylogenetic analysis of a 371 bp segment of the VP1/P2A junction of six isolates obtained from stool samples showed the exclusive emergence of genetically related HAV subgenotype IA. All the isolates clustered within a unique lineage exhibiting a 99.5% nucleotide identity suggesting infection from a common source. The Cameroonian HAV isolates did not intermix or cluster with those from other regions of Africa and the rest of the world. Tajima's neutralization tests using the six sequences suggested HAV/IA population expansion (D = -1.37; P = 0.016). This is the first description of indigenous HAV genotypes circulating in Cameroon revealing a community-wide spread and predominance of HAV/1A infection in the Kumba area. These findings stress the need for routine molecular tracking of HAV infection as a contributory cause of acute diarrhea in Cameroonian children. Copyright © 2012 Wiley Periodicals, Inc.

Inner-shelf circulation and sediment dynamics on a series of shoreface connected ridges offshore of Fire Island, NY

USGS Publications Warehouse

Warner, John C.; List, Jeffrey H.; Schwab, William C.; Voulgaris, George; Armstrong, Brandy N.; Marshall, N

2014-01-01

Locations along the inner-continental shelf offshore of Fire Island, NY, are characterized by a series of shoreface connected ridges (SFCRs). These sand ridges have approximate dimensions of 10 km in length, 3 km spacing, up to ~8 m ridge to trough relief, and are oriented obliquely at approximately 30 degrees clockwise from the coastline. Stability analysis from previous studies explains how sand ridges such as these could be formed and maintained by storm-driven flows directed alongshore with a key maintenance mechanism of offshore deflected flows over ridge crests and onshore in the troughs. We examine these processes both with a limited set of idealized numerical simulations and analysis of observational data. Model results confirm that along-shore flows over the SFCRs exhibit offshore veering of currents over the ridge crests and onshore-directed flows in the troughs, and demonstrate the opposite circulation pattern for a reverse wind. To further investigate these maintenance processes, oceanographic instruments were deployed at seven sites on the SFCRs offshore of Fire Island to measure water levels, ocean currents, waves, suspended-sediment concentrations, and bottom stresses from January to April 2012. Data analysis reveals that during storms with winds from the northeast the processes of offshore deflection of currents over ridge crests and onshore in the troughs were observed, and during storm events with winds from the southwest a reverse flow pattern over the ridges occurred. Computations of suspended-sediment fluxes identify periods that are consistent with SFCR maintenance mechanisms. Alongshore winds from the northeast drove fluxes offshore on the ridge crest and onshore in the trough that would tend to promote ridge maintenance. However, alongshore winds from the southwest drove opposite circulations. The wind fields are related to different storm types that occur in the region (low pressure systems, cold fronts, and warm fronts). From the limited data set we identify that low pressure systems drive sediment fluxes that tend to promote stability and maintain the SFCRs, while cold front type storms appear to drive circulations that are in the opposite sense and may not be a supporting mechanism for ridge maintenance.

Response of the Surface Circulation of the Arabian Sea to Monsoonal Forcing

NASA Astrophysics Data System (ADS)

Beal, L. M.; Hormann, V.; Lumpkin, R.; Foltz, G. R.

2014-12-01

We use two decades of drifter and satellite data to examine the monthly evolution of the surface circulation of the Arabian Sea, which reverses annually in response to the Indian monsoon winds. Most significantly, we find that in the transition from winter to summer circulations, northward flow appears along the length of the western boundary as early as March or April, one or two months before the onset of the southwest monsoon winds. This reversal is initiated by annual Rossby waves, which in turn are initiated by wind curl forcing during the previous southwest monsoon. These results lead us to speculate that there is an oceanic mechanism through which one monsoon may precondition the next. Previous studies of monsoon circulations with lower temporal resolution have highlighted basin-wide currents and connections that are not found to exist in the monthly fields. In particular, we find that the Northeast Monsoon Current does not reach the western boundary and there is no counter-rotating gyre system during boreal winter. South of the equator, the eastward-flowing South Equatorial Counter Current (SECC) is present year-round, even though equatorial winds are strongly influenced by the monsoons. Semi-annual variability of the SECC is governed by Ekman pumping over the south equatorial gyre (or Seychelles dome) and, surprisingly, it is weakest during the northeast monsoon. This region has important influence on the atmosphere and its link to the monsoons deserves further investigation. The East African Coastal Current feeds into the SECC from the boundary. During the southwest monsoon it overshoots the equator and splits, feeding both northward into the Somali Current and eastward into the SECC after looping back across the equator. This apparent retroflection of the EACC is what was previously known as the southern gyre and is obscured at the surface by strong, locally wind-driven, cross-equatorial Ekman transport. Finally, there is broad, strong eastward flow at the mouth of the Gulf of Aden throughout the southwest monsoon, which is influenced by the curvature and bifurcation of the atmospheric monsoon jet.

DEFORMATION AND FRACTURE OF POORLY CONSOLIDATED MEDIA - Borehole Failure Mechanisms in High-Porosity Sandstone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bezalel c. Haimson

2005-06-10

We investigated failure mechanisms around boreholes and the formation of borehole breakouts in high-porosity sandstone, with particular interest to grain-scale micromechanics of failure leading to the hitherto unrecognized fracture-like borehole breakouts and apparent compaction band formation in poorly consolidated granular materials. We also looked at a variety of drilling-related factors that contribute to the type, size and shape of borehole breakouts. The objective was to assess their effect on the ability to establish correlations between breakout geometry and in situ stress magnitudes, as well as on borehole stability prediction, and hydrocarbon/water extraction in general. We identified two classes of mediummore » to high porosity (12-30%) sandstones, arkosic, consisting of 50-70% quartz and 15 to 50% feldspar, and quartz-rich sandstones, in which quartz grain contents varied from 90 to 100%. In arkose sandstones critical far-field stress magnitudes induced compressive failure around boreholes in the form of V-shaped (dog-eared) breakouts, the result of dilatant intra-and trans-granular microcracking subparallel to both the maximum horizontal far-field stress and to the borehole wall. On the other hand, boreholes in quartz-rich sandstones failed by developing fracture-like breakouts. These are long and very narrow (several grain diameters) tabular failure zones perpendicular to the maximum stress. Evidence provided mainly by SEM observations suggests a failure process initiated by localized grain-bond loosening along the least horizontal far-field stress springline, the packing of these grains into a lower porosity compaction band resembling those discovered in Navajo and Aztec sandstones, and the emptying of the loosened grains by the circulating drilling fluid starting from the borehole wall. Although the immediate several grain layers at the breakout tip often contain some cracked or even crushed grains, the failure mechanism enabled by the formation of the compaction band is largely non-dilatant, a major departure from the dilatant mechanism observed in Tablerock sandstone. The experimental results suggest that unlike our previous assertion, the strength of grain bonding and the mineral composition, rather than the porosity, are major factors in the formation of compaction bands and the ensuing fracture-like breakouts. Some breakout dimensions in all rocks were correlatable to the far-field principal stresses, and could potentially be used (in conjunction with other information) as indicators of their magnitudes. However, we found that several factors can significantly influence breakout geometry. Larger boreholes and increased drilling-fluid flow rates produce longer fracture-like breakouts, suggesting that breakouts in field-scale wellbores could reach considerable lengths. On the other hand, increased drilling-fluid weight and increased drill-bit penetration rate resulted in a decrease in breakout length. These results indicate that breakout growth can be controlled to some degree by manipulating drilling variables. Realizing how drilling variables impact borehole breakout formation is important in understanding the process by which breakouts form and their potential use as indicators of the far-field in situ stress magnitudes and as sources of sand production. As our research indicates, the final breakout size and mechanism of formation can be a function of several variables and conditions, meaning there is still much to be understood about this phenomenon.« less

Time-dependent wellbore breakout growth caused by drilling-induced pore pressure transients: Implications for estimations of far field stress magnitude

NASA Astrophysics Data System (ADS)

Olcott, K. A.; Saffer, D. M.; Elsworth, D.

2013-12-01

One method used to constrain principal stress orientations and magnitudes in the crust combines estimates of rock strength with observations of wellbore failures, including drilling-induced tensile fractures (DITF) and compressional borehole breakouts (BO). This method has been applied at numerous Integrated Ocean Drilling Program (IODP) boreholes drilled into sediments in a wide range of settings, including the Gulf of Mexico, the N. Japan and Costa Rican subduction margins, and the Nankai Trough Accretionary Prism. At Nankai and N. Japan, BO widths defined by logging-while-drilling (LWD) resistivity images have been used to estimate magnitudes of far-field horizontal tectonic stresses. At several drillsites (C0010, C0002, and C0011), sections of the borehole were relogged with LWD after the hole was left open for times ranging from ~30 min to 3 days; times between acquisition were associated with pipe connections (~30 min), cleaning and circulating the hole (up to ~3 hr), and evacuation of the site for weather (~3 days). Relogged portions exhibit widening of BO, hypothesized to reflect time-dependent re-equilibration of instantaneous changes in pore fluid pressure (Pf) induced by opening the borehole. In this conceptual model, Pf decrease caused by initial excavation of the borehole and resulting changes in the state of stress at the borehole wall lead to an initial strengthening of the sediment. Re-equilibration of Pf results in time-dependent weakening of the sediment and subsequent BO growth. If correct, this hypothesis implies that stress magnitudes estimated by BO widths could be significantly underestimated. We test this idea using a finite-element model in COMSOL multiphysics that couples fluid flow and deformation in a poroelastic medium. We specify far-field horizontal principal stresses (SHmax and Shmin) in the model domain. At the start of simulations/at the time of borehole opening, we impose a decreased stress at the borehole wall. We consider a range of sediment permeability from 10-18 m2 to 10-14 m2. We find Pf initially increases at the borehole wall over a range of azimuths +/-~60° from Shmin, with a maximum increase of 10 MPa (4.4% of the maximum principal stress (σ1) at the borehole wall) and would lead to weakening of the rock. Pf decreases over a range of azimuths +/- ~30° from SHmax, with a maximum decrease of 10 MPa (8.8% of σ1), leading to initial strengthening of the rock. Evolution of Pf depends strongly on sediment permeability: Pf is 90% equilibrated at the borehole wall in ~43 minutes for a permeability of 10-18 m2, whereas for a permeability of 10-14 m2, Pf equilibrates nearly instantaneously. Since BO form parallel to Shmin, BO growth driven by drilling-induced Pf changes require that the initial BO be wider than ~120°, or outside the zone of initially increased Pf. This is not consistent with observations of BO growth, where initial BO are 0-25° and grow up to 125°. In contrast, our results imply that analyses based on BO measured immediately after drilling could overestimate far-field stresses because the BO are formed in sediments weakened by poroelastic pressure changes. Future work will focus on systematic investigation of the role of far field stresses and different sediment rheologies on the distribution of pore pressure change around the wellbore.

ICDP supported coring in IDDP-2 at Reykjanes - the DEEPEGS demonstrator in Iceland - Supercritical conditions reached below 4.6 km depth.

NASA Astrophysics Data System (ADS)

Ómar Friðleifsson, Guðmundur; Elders, Wilfred A.; Zierenberg, Robert; Steafánsson, Ari; Sigurðsson, Ómar; Gíslason, Þór; Weisenberger, Tobias B.; Harðarson, Björn S.; Mesfin, Kiflom G.

2017-04-01

The Iceland Deep Drilling Project (IDDP) is exploring the technical and economic feasibility of producing supercritical geothermal resources. The IDDP-2 well is located in the Reykjanes saline geothermal system in SW Iceland, on the landward extension of the Mid-Atlantic Ridge, where we are probing the analog of the root zone of a black smoker. In 2009, Phase 1 of the IDDP was unsuccessful in reaching supercritical conditions in the Krafla volcanic caldera in NE Iceland, when the IDDP-1 drill hole unexpectedly encountered 900°C rhyolite magma at only 2.1 km depth. The completed well produced superheated steam with a well head temperature of 453°C with an enthalpy and flow rate sufficient to generate 35 MWe. Drilling the IDDP-2 began by deepening an existing 2.5 km deep production well (RN-15) to 3 km depth, casing it to 2941m depth and drilling it to 4626m. Total circulation losses which were encountered below 3 km depth, could not be cured by LCM and multiple cement jobs. Accordingly, drilling continued "blind" to total depth, without return of drill cuttings. We attempted 12 core runs below 3 km depth, half of which recovered some core. The cores are basalts and dolerites with alteration ranging from upper greenschist facies to amphibolite facies, suggesting formation temperatures >450°C. After a final report from the on-site science team, expected mid-year 2017, detailed petrological, petrophysical, and geochemical analyses of cores will be undertaken by the IDDP science team and collaborators and published in a special issue of a main-stream scientific journal. The drilling of the IDDP-2 was funded by the field operator HS Orka, and by Statoil, and the IDDP industry consortium. The coring was funded by ICDP and the science program of the IDDP. Deepening the RN-15 began 11th August 2016, and was completed to 4626m, 17th December 2016. A perforated liner was inserted to 4,571m and the well subsequently logged for temperature, pressure and injectivity, after 6 days partial heating-up. The injectivity index proved to be 1.7 (kg/s)/bar. Supercritical conditions were measured at the bottom, 427°C at 340 bar pressure. The T-log showed the main permeable zones to be at around 3360m, 4200m, 4370m and 4550m depth. Estimates suggest that 30% of 40 L/s injected into the well are received by the three deepest feed zones. This can possibly be enhanced by massive soft stimulation, which is a part of the DEEPEGS plan to be executed later this year. The DEEPEGS project is a demonstration project, supported by the European Commission, Horizon 2020. The goal is to demonstrate the feasibility of enhanced geothermal systems (EGS) for delivering energy from renewable resources in Europe. It is a four-year project coordinated by HS Orka, Iceland, in cooperation with partners from Iceland, France, Germany, Italy, and Norway. The project will demonstrate advanced technologies in three types of geothermal reservoirs, (i) in high enthalpy resource beneath existing hydrothermal field at Reykjanes with temperature up to 550°C, and (ii) in two very deep hydrothermal reservoirs in France with temperatures up to 220°C.

Fault imprint in clay units: magnetic fabric, structural and mineralogical signature

NASA Astrophysics Data System (ADS)

Moreno, Eva; Homberg, Catherine; Schnyder, Johann; Person, Alain; du Peloux1, Arthur; Dick, Pierre

2014-05-01

Fault-induced deformations in clay units can be difficult to decipher because strain markers are not always visible at outcrop scale or using geophysical methods. Previous studies have indicated that the anisotropy of magnetic susceptibility (ASM) provides a powerful and rapid technique to investigate tectonic deformation in clay units even when they appear quite homogenous and undeformed at the outcrop scale (Lee et al. 1990, Mattei et al. 1997). We report here a study based on ASM, structural analysis and magnetic and clay mineralogy from two boreholes (TF1 and ASM1)drilled horizontally in the Experimental Station of Tournemire of the Institute for Radiological Protection and Nuclear Safety (IRSN) in Aveyron (France). The boreholes intersect a N-S trending strike-slip fault from west to east. The ASM study indicates the evolution of the magnetic fabric from the undeformed host rock to the fault core. Also, all the fractures cutting the studied interval of the core have been measured as well as the slip vectors which are generally well preserved. In the two boreholes, the undeformed sediments outside the fault zone are characterized by an oblate fabric, a sub-vertical minimum susceptibility axis (k3) perpendicular to the bedding plane and without magnetic lineation. Within the fault zone, a tilt in the bedding plane has been observed in two boreholes TF1 and ASM1. In addition, in the TF1 core, the fault area presents a tectonic fabric characterized by a triaxial AMS ellipsoid. Moreover, the magnetic lineation increases and k3 switches from a vertical to a sub-horizontal plane. This kind of fabric has not been observed in borehole ASM1. The structural analysis of the individual fractures making the fault zone indicates a complex tectonic history with different imprint in the two fault segments cut by the two boreholes. The large majority of fractures correspond to dextral strike-slip faults but normal and reverse movements were observed and are more or less frequent depending on the borehole. Notably, many fractures are low angle faults (dip<45°) and may bear both strike-slip or normal striae. The mineralogical study based on X-ray diffraction analysis, have pointed out some variations in clay minerals associations nearby the deformed zones that may be the result of fluid circulation along the fault system which is in agreement with the presence of goethite determined by low magnetic temperature measurements. This multi-proxi study, combining ASM, petrostructural and mineralogical approaches has highlighted the heterogeneity of the fault, but also its past role as a drain to fluid circulation.

10Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core.

PubMed

Raisbeck, G M; Yiou, F; Cattani, O; Jouzel, J

2006-11-02

An ice core drilled at Dome C, Antarctica, is the oldest ice core so far retrieved. On the basis of ice flow modelling and a comparison between the deuterium signal in the ice with climate records from marine sediment cores, the ice at a depth of 3,190 m in the Dome C core is believed to have been deposited around 800,000 years ago, offering a rare opportunity to study climatic and environmental conditions over this time period. However, an independent determination of this age is important because the deuterium profile below a depth of 3,190 m depth does not show the expected correlation with the marine record. Here we present evidence for enhanced 10Be deposition in the ice at 3,160-3,170 m, which we interpret as a result of the low dipole field strength during the Matuyama-Brunhes geomagnetic reversal, which occurred about 780,000 years ago. If correct, this provides a crucial tie point between ice cores, marine cores and a radiometric timescale.

The Influence of Baker Bay and Sand Island on Circulations in the Mouth of the Columbia River

DTIC Science & Technology

2014-06-01

the presence of Baker Bay, a shallow sub -embayment, adds further complexity. Drifter velocities were greatest during maximum ebb flows and were...Drifters occasionally entered Baker Bay via Baker Inlet during flood flows , especially in conjunction with strong southwesterly winds. During ebb flows ...occurred in the vicinity of the pile dikes, including reversed (upriver) flow between the pile dikes during maximum ebb . Understanding unique flow

30 CFR 57.7009 - Drill helpers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drill helpers. 57.7009 Section 57.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7009 Drill helpers. If a drill helper assists the drill operator during movement...

30 CFR 57.7009 - Drill helpers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drill helpers. 57.7009 Section 57.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7009 Drill helpers. If a drill helper assists the drill operator during movement...

30 CFR 57.7009 - Drill helpers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drill helpers. 57.7009 Section 57.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7009 Drill helpers. If a drill helper assists the drill operator during movement...

30 CFR 57.7009 - Drill helpers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill helpers. 57.7009 Section 57.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7009 Drill helpers. If a drill helper assists the drill operator during movement...

30 CFR 57.7009 - Drill helpers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drill helpers. 57.7009 Section 57.7009 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7009 Drill helpers. If a drill helper assists the drill operator during movement...

Estimating gas kick arrival to better manage surface flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merryman, J.

1997-06-01

There are many quality, expertly designed programs for teaching rig crews prevention and control of well kicks. Much time and money has been spent training rig crews for procedures and methods to avoid kicks, and what to do if you have one, even though all accepted practices were followed. One false/bad result from this training is that individuals have come away from this training believing that once a gas kick is circulated through the choke, all problems are simple and manageable, i.e., the danger has passed. What you do with gas once it is downstream of the choke has notmore » been given enough emphasis in some training programs, including the one the author is involved in. This article, prepared from experiences on actual rig locations in Wyoming and Argentina, and developed for well control training in Parker Drilling Co.`s Training Center, Odessa, Texas, describes a method for estimating the time, in pump strokes and/or minutes, for a gas kick to reach surface. Reducing pump strokes (circulating flowrate) and knowing available time to gas kick arrival allows the crew to prepare surface handling equipment. Common misconceptions about gas handling and potential resulting problems are noted. An example calculation describes the calculation procedure.« less

Oxygen and carbon isotope ratios of hydrothermal minerals from Yellowstone drill cores

USGS Publications Warehouse

Sturchio, N.C.; Keith, T.E.C.; Muehlenbachs, K.

1990-01-01

Oxygen and carbon isotope ratios were measured for hydrothermal minerals (silica, clay and calcite) from fractures and vugs in altered rhyolite, located between 28 and 129 m below surface (in situ temperatures ranging from 81 to 199??C) in Yellowstone drill holes. The purpose of this study was to investigate the mechanism of formation of these minerals. The ??18O values of the thirty-two analyzed silica samples (quartz, chalcedony, ??-cristobalite, and ??-cristobalite) range from -7.5 to +2.8???. About one third of the silica 7samples have ??18O values that are consistent with isotopic equilibrium with present thermal waters; most of the other silica samples appear to have precipitated from water enriched in 18O (up to 4.7???) relative to present thermal water, assuming precipitation at present in situ temperatures. Available data on fluid-inclusion homogenization temperatures in hydrothermal quartz indicate that silica precipitation occurred mostly at temperatures above those measured during drilling and imply that 15O enrichments in water during silica precipitation were generally larger than those estimated from present conditions. Similarly, clay minerals (celadonite and smectite) have ??18O values higher (by 3.5 to 7.9???) than equilibrium values under present conditions. In contrast, all eight analyzed calcite samples are close to isotopic equilibrium with present thermal waters. The frequent incidence of apparent 18O enrichment in thermal water from which the hydrothermal minerals precipitated may indicate that a higher proportion of strongly 18O-enriched deep hydrothermal fluid once circulated through shallow portions of the Yellowstone system, or that a recurring transient 18O-enrichment effect occurs at shallow depths and is caused either by sudden decompressional boiling or by isotopic exchange at low water/rock ratios in new fractures. The mineralogy and apparent 18O enrichments of hydrothermal fracture-filling minerals are consistent with deposition during transient boiling or rock-water exchange (fracturing) events. ?? 1990.

Popular epidemiology and "fracking": citizens' concerns regarding the economic, environmental, health and social impacts of unconventional natural gas drilling operations.

PubMed

Powers, Martha; Saberi, Poune; Pepino, Richard; Strupp, Emily; Bugos, Eva; Cannuscio, Carolyn C

2015-06-01

Pennsylvania sits atop the Marcellus Shale, a reservoir of natural gas that was untapped until the 2004 introduction of unconventional natural gas drilling operations (UNGDO) in the state. Colloquially known as fracking, UNGDO is a controversial process that employs large volumes of water to fracture the shale and capture gas; it has become a multi-billion dollar industry in Pennsylvania. We analyzed letters to the editor of the most widely circulated local newspaper in the most heavily drilled county in Pennsylvania (Bradford County) in order to characterize residents' concerns and their involvement in popular epidemiology--the process by which citizens investigate risks associated with a perceived environmental threat. We reviewed 215 letters to the editor that referenced natural gas operations and were published by The Daily Review between January 1, 2008 and June 8, 2013. We used NVivo 10 to code and analyze letters and identify major themes. Nvivo is qualitative data analysis software (http://www.qsrinternational.com/products_nvivo.aspx) that allows researchers to code and analyze "unstructured" data, including text files of any type (e.g., interview transcripts, news articles, letters, archival materials) as well as photographs and videos. Nvivo can be used to classify, sort, query, comment on, and share data across a research group. Letters demonstrated citizen engagement in beginning and intermediate stages of lay epidemiology, as well as discord and stress regarding four main issues: socio-economic impacts, perceived threats to water, population growth and implications, and changes to the rural landscape. Residents called for stronger scientific evidence and a balance of economic development and health and environmental protections. Citizens' distress regarding UNGDO appeared to be exacerbated by a dearth of information to guide economic growth and health, environmental, and social concerns. This analysis proposes locally informed questions to guide future surveillance and research.

Quaternary geology of the DFDP-2 drill holes, Alpine Fault, New Zealand

NASA Astrophysics Data System (ADS)

Upton, P.; Cox, S.; Howarth, J. D.; Sutherland, R.; Langridge, R.; Barth, N. C.; Atkins, C.

2015-12-01

A 240 m-thick Quaternary sediment sequence in Whataroa Valley was much thicker than predicted before drilling. DFDP-2A and DFDP-2B were mostly drilled through the sequence by dual-rotary method using air or water circulation, returning cuttings bagged at 1 or 2 m sample intervals. Some sorting/bias and contamination occurred. Core was retrieved in DFDP-2A from 125-160 m, with highly variable recovery (0-100%) and mixed preservation/quality. The sequence is interpreted to comprise: fluvial-glacial gravels (0-58 m); grading downward into sandy lake delta sediments (59-77 m); overlying a monotonous sequence of lake mud and silts, with rare pebble-cobble diamictite (77-206 m); with a basal unit (206-240 m) containing coarse cobbles and boulders that may represent a distinct till/diamictite. Evidence has yet to be found for any marine influence in lowermost sediments, despite deposition at least 120 m below present day sea level, and potentially 200 m bsl if uplift has occurred on the Alpine Fault. When corrected for uplift the lacustrine sequence broadly correlates to those in present Lakes Rotokina and Wahapo, suggesting a substantial (~100 km2) pro-glacial lake once covered the area. Radiocarbon dating of plant fragments indicate 70 m of upper lacustrine and deltaic sediments (129-59 m) were deposited rapidly between 16350-15800 Cal BP. Overlying alluvial gravels are much younger (<1 ka), but potentially also involved pulses of rapid aggradation. The sequence provides a record of sedimentation on the Alpine Fault hanging wall following late-glacial ice retreat up Whataroa Valley, with uplift and erosion followed by Holocene alluvial gravel deposition. Future work will address: (1) the nature and history of sedimentation, including the lithology and origin of sediments; (2) what, if any, geological record of tectonics (movement) or Alpine Fault earthquakes (shaking) the sediments contain.

Study on drilling induced delamination of woven kenaf fiber reinforced epoxy composite using carbide drills

NASA Astrophysics Data System (ADS)

Suhaily, M.; Hassan, C. H. Che; Jaharah, A. G.; Azmi, H.; Afifah, M. A.; Khairusshima, M. K. Nor

2018-04-01

In this research study, it presents the influences of drilling parameters on the delamination factor during the drilling of woven kenaf fiber reinforced epoxy composite laminates when using the carbide drill bits. The purpose of this study is to investigate the influence of drilling parameters such as cutting speed, feed rate and drill sizes on the delamination produced when drilling woven kenaf reinforced epoxy composite using the non-coated carbide drill bits. The damage generated on the woven kenaf reinforced epoxy composite laminates were observed both at the entrance and exit surface during the drilling operation. The experiments were conducted according to the Box Behnken experimental designs. The results indicated that the drill diameter has a significant influence on the delamination when drilling the woven kenaf fiber reinforced epoxy composites.

Drilling systems for extraterrestrial subsurface exploration.

PubMed

Zacny, K; Bar-Cohen, Y; Brennan, M; Briggs, G; Cooper, G; Davis, K; Dolgin, B; Glaser, D; Glass, B; Gorevan, S; Guerrero, J; McKay, C; Paulsen, G; Stanley, S; Stoker, C

2008-06-01

Drilling consists of 2 processes: breaking the formation with a bit and removing the drilled cuttings. In rotary drilling, rotational speed and weight on bit are used to control drilling, and the optimization of these parameters can markedly improve drilling performance. Although fluids are used for cuttings removal in terrestrial drilling, most planetary drilling systems conduct dry drilling with an auger. Chip removal via water-ice sublimation (when excavating water-ice-bound formations at pressure below the triple point of water) and pneumatic systems are also possible. Pneumatic systems use the gas or vaporization products of a high-density liquid brought from Earth, gas provided by an in situ compressor, or combustion products of a monopropellant. Drill bits can be divided into coring bits, which excavate an annular shaped hole, and full-faced bits. While cylindrical cores are generally superior as scientific samples, and coring drills have better performance characteristics, full-faced bits are simpler systems because the handling of a core requires a very complex robotic mechanism. The greatest constraints to extraterrestrial drilling are (1) the extreme environmental conditions, such as temperature, dust, and pressure; (2) the light-time communications delay, which necessitates highly autonomous systems; and (3) the mission and science constraints, such as mass and power budgets and the types of drilled samples needed for scientific analysis. A classification scheme based on drilling depth is proposed. Each of the 4 depth categories (surface drills, 1-meter class drills, 10-meter class drills, and deep drills) has distinct technological profiles and scientific ramifications.

The dipeptidyl peptidase-4 inhibitor Saxagliptin improves function of circulating pro-angiogenic cells from type 2 diabetic patients

PubMed Central

2014-01-01

Background Type 2 diabetes (T2D) is associated with reduction and dysfunction of circulating pro-angiogenic cells (PACs). DPP-4 inhibitors, a class of oral agents for T2D, might possess pleiotropic vasculoprotective activities. Herein, we tested whether DPP-4 inhibition with Saxagliptin affects the function of circulating PACs from T2D and healthy subjects. Methods PACs were isolated from T2D (n = 20) and healthy (n = 20) subjects. Gene expression, clonogenesis, proliferation, adhesion, migration and tubulisation were assessed in vitro by incubating PACs with or without Saxagliptin and SDF-1α. Stimulation of angiogenesis by circulating cells from T2D patients treated with Saxagliptin or other non-incretinergic drugs was assessed in vivo using animal models. Results Soluble DPP-4 activity was predominant over cellular activity and was successfully inhibited by Saxagliptin. At baseline, T2D compared to healthy PACs contained less acLDL+Lectin+ cells, and showed altered expression of genes related to adhesion and cell cycle regulation. This was reflected by impaired adhesion and clonogenesis/proliferative response of T2D PACs. Saxagliptin + SDF-1α improved adhesion and tube sustaining capacity of PACs from T2D patients. CD14+ PACs were more responsive to Saxagliptin than CD14- PACs. While Saxagliptin modestly reduced angiogenesis by mature endothelial cells, circulating PACs-progeny cells from T2D patients on Saxagliptin treatment displayed higher growth factor-inducible in vivo angiogenetic activity, compared to cells from T2D patients on non-incretinergic regimen. Conclusions Saxagliptin reverses PACs dysfunction associated with T2D in vitro and improves inducible angiogenesis by circulating cells in vivo. These data add knowledge to the potential pleiotropic cardiovascular effects of DPP-4 inhibition. PMID:24886621

The dipeptidyl peptidase-4 inhibitor saxagliptin improves function of circulating pro-angiogenic cells from type 2 diabetic patients.

PubMed

Poncina, Nicol; Albiero, Mattia; Menegazzo, Lisa; Cappellari, Roberta; Avogaro, Angelo; Fadini, Gian Paolo

2014-05-14

Type 2 diabetes (T2D) is associated with reduction and dysfunction of circulating pro-angiogenic cells (PACs). DPP-4 inhibitors, a class of oral agents for T2D, might possess pleiotropic vasculoprotective activities. Herein, we tested whether DPP-4 inhibition with Saxagliptin affects the function of circulating PACs from T2D and healthy subjects. PACs were isolated from T2D (n = 20) and healthy (n = 20) subjects. Gene expression, clonogenesis, proliferation, adhesion, migration and tubulisation were assessed in vitro by incubating PACs with or without Saxagliptin and SDF-1α. Stimulation of angiogenesis by circulating cells from T2D patients treated with Saxagliptin or other non-incretinergic drugs was assessed in vivo using animal models. Soluble DPP-4 activity was predominant over cellular activity and was successfully inhibited by Saxagliptin. At baseline, T2D compared to healthy PACs contained less acLDL(+)Lectin(+) cells, and showed altered expression of genes related to adhesion and cell cycle regulation. This was reflected by impaired adhesion and clonogenesis/proliferative response of T2D PACs. Saxagliptin + SDF-1α improved adhesion and tube sustaining capacity of PACs from T2D patients. CD14+ PACs were more responsive to Saxagliptin than CD14- PACs. While Saxagliptin modestly reduced angiogenesis by mature endothelial cells, circulating PACs-progeny cells from T2D patients on Saxagliptin treatment displayed higher growth factor-inducible in vivo angiogenetic activity, compared to cells from T2D patients on non-incretinergic regimen. Saxagliptin reverses PACs dysfunction associated with T2D in vitro and improves inducible angiogenesis by circulating cells in vivo. These data add knowledge to the potential pleiotropic cardiovascular effects of DPP-4 inhibition.

Association between circulating irisin and insulin resistance in non-diabetic adults: A meta-analysis.

PubMed

Qiu, Shanhu; Cai, Xue; Yin, Han; Zügel, Martina; Sun, Zilin; Steinacker, Jürgen Michael; Schumann, Uwe

2016-06-01

Exogenous administration of recombinant irisin improves glucose metabolism. However, the association of endogenous circulating (plasma/serum) irisin with insulin resistance remains poorly delineated. This study was aimed to examine this association by meta-analyzing the current evidence without study design restriction in non-diabetic adults. Peer-reviewed studies written in English from 3 databases were searched to December 2015. Studies that reported the association between circulating irisin and insulin resistance (or its reverse, insulin sensitivity) in non-diabetic non-pregnant adults (mean ages ≥18years) were included. The pooled correlation coefficient (r) and 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup analyses and meta-regression were performed to explore potential sources of heterogeneity. Of the 195 identified publications, 17 studies from 15 articles enrolling 1912 participants reported the association between circulating irisin and insulin resistance. The pooled effect size was 0.15 (95% CI: 0.07 to 0.22) with a substantial heterogeneity (I(2)=55.5%). This association seemed to be modified by glycemic status (fasting blood glucose ≥6.1mmol/L versus <6.1mmol/L) and racial-ethnic difference (Asians versus Europeans versus Americans), but not by sex difference, sampling time-point, blood sample type, ELISA kits used, baseline age, or body mass index. Circulating irisin was inversely associated with insulin sensitivity (6 studies; r=-0.17, 95% CI: -0.25 to -0.09). Circulating irisin is directly and positively associated with insulin resistance in non-diabetic adults. However, this association is rather small and requires further clarification, in particular by well-designed large epidemiological studies with overall, race-, and sex-specific analyses. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The Regional Water Cycle and Water Ice Clouds in the Tharsis - Valles Marineris System

NASA Astrophysics Data System (ADS)

Leung, C. W. S.; Rafkin, S. C.

2017-12-01

The regional atmospheric circulation on Mars is highly influenced by local topographic gradients. Terrain-following air parcels forced along the slopes of the major Tharsis volcanoes and the steep canyon walls of Valles Marineris significantly impact the local water vapor concentration and the associated conditions for cloud formation. Using a non-hydrostatic mesoscale atmospheric model with aerosol & cloud microphysics, we investigate the meteorological conditions for water ice cloud formation in the coupled Tharsis - Valles Marineris system near the aphelion season. The usage of a limited area regional model ensures that topographic slopes are well resolved compared to the typical resolutions of a global-coverage general circulation model. The effects of shadowing and slope angle geometries on the energy budget is also taken into account. Diurnal slope winds in complex terrains are typically characterized by the reversal of wind direction twice per sol: upslope during the day, and downslope at night. However, our simulation results of the regional circulation and diurnal water cycle indicate substantial asymmetries in the day-night circulation. The convergence of moist air masses enters Valles Marineris via easterly flows, whereas dry air sweep across the plateau of the canyon system from the south towards the north. We emphasize the non-uniform vertical distribution of water vapor in our model results. Water vapor mixing ratios in the lower planetary boundary layer may be factors greater than the mixing ratio aloft. Water ice clouds are important contributors to the climatic forcing on Mars, and their effects on the mesoscale circulations in the Tharsis - Valles Marineris region significantly contribute to the regional perturbations in the large-scale global atmospheric circulation.

Recent outbreak of aseptic meningitis in Italy due to Echovirus 30 and phylogenetic relationship with other European circulating strains.

PubMed

Milia, Maria Grazia; Cerutti, Francesco; Gregori, Gabriella; Burdino, Elisa; Allice, Tiziano; Ruggiero, Tina; Proia, Maria; De Rosa, Giulia; Enrico, Eugenia; Lipani, Filippo; Di Perri, Giovanni; Ghisetti, Valeria

2013-11-01

Enteroviruses (EVs) are common human viral pathogens, causing a variety of diseases, including aseptic meningitis. Recently, EV aseptic meningitis outbreaks have been reported across Europe, but, in Italy, knowledge of recent EV molecular epidemiology is very limited. We report an outbreak of EV aseptic meningitis in 10 adults in North-Western Italy, from October to November 2012. Patients were parents or close relatives of children <5 years old attending the same class of a nursery school, suffering from a mild febrile upper respiratory disease. Phylogenetic relationship with other European circulating strains was analyzed updating E30 circulation in Italy in recent years. EVs were detected from cerebrospinal fluid (CSF) specimens with a real-time reverse transcription polymerase chain reaction and virus isolation was achieved from rectal and pharyngeal swabs. For cluster definition and phylogenetic studies, viral VP1 region was directly amplified and sequenced from CSF. EVs were identified in CSF from all patients and from rectal and pharyngeal swabs in 7 of them. Direct sequencing of CSF revealed the presence of the same Echovirus 30 (E30) in all patients and phylogenetic analysis identified it as a diverging clade within E30 genotype VII, the most recent strain circulating in UK, Finland and Denmark since 2006. Molecular techniques allowed the rapid identification and typing of E30 from CSF. Phylogenetic analysis revealed that the cluster might be due to a new E30 variant within the genotype VII currently circulating in Europe, thus updating the epidemiology of EV circulation in Italy. Copyright © 2013 Elsevier B.V. All rights reserved.

Impedance matched joined drill pipe for improved acoustic transmission

DOEpatents

Moss, William C.

2000-01-01

An impedance matched jointed drill pipe for improved acoustic transmission. A passive means and method that maximizes the amplitude and minimize the temporal dispersion of acoustic signals that are sent through a drill string, for use in a measurement while drilling telemetry system. The improvement in signal transmission is accomplished by replacing the standard joints in a drill string with joints constructed of a material that is impedance matched acoustically to the end of the drill pipe to which it is connected. Provides improvement in the measurement while drilling technique which can be utilized for well logging, directional drilling, and drilling dynamics, as well as gamma-ray spectroscopy while drilling post shot boreholes, such as utilized in drilling post shot boreholes.

Effects of bone drilling on local temperature and bone regeneration: an in vivo study.

PubMed

Karaca, Faruk; Aksakal, Bünyamin; Köm, Mustafa

2014-01-01

The aim of this study was to examine the influence of bone drilling on local bone temperature and bone regeneration and determine optimal drilling speed and pressure in an animal model. The study included 12 skeletally mature New Zealand white rabbits, weighing between 2.8 to 3.2 kg. Rabbits were divided into 2 groups and euthanized at the end of Day 21 (Group A) and Day 42 (Group B). The same drilling protocol was used in both groups. Three drill holes with different pressure (5, 10 and 20 N) were made in each rabbit tibias using 3 different rotational drill speeds (230, 370 and 570 rpm). During drilling, local temperature was recorded. Rabbit tibia underwent histopathological exam for bone regeneration. Bone temperature was affected by drilling time and depth. Lower drill speeds reduced the bone temperature and revealed better bone regeneration when compared to the drilled bones at higher drill speeds. Titanium boron nitride coating on the drill bits had no significant effects on bone temperature and structure. Bone regeneration was superior in Group B rabbits that had drilling at 230 rpm and 20 N. Our results suggested that lower drilling speed with higher pressure is necessary for better bone regeneration. The optimal drilling speed is 230 rpm and optimal drilling pressure 20 N.

Remote Whispering Applying Time Reversal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Brian Eric

The purpose of this project was to explore the use of time reversal technologies as a means for communication to a targeted individual or location. The idea is to have the privacy of whispering in one’s ear, but to do this remotely from loudspeakers not located near the target. Applications of this work include communicating with hostages and survivors in rescue operations, communicating imaging and operational conditions in deep drilling operations, monitoring storage of spent nuclear fuel in storage casks without wires, or clandestine activities requiring signaling between specific points. This technology provides a solution in any application where wiresmore » and radio communications are not possible or not desired. It also may be configured to self calibrate on a regular basis to adjust for changing conditions. These communications allow two people to converse with one another in real time, converse in an inaudible frequency range or medium (i.e. using ultrasonic frequencies and/or sending vibrations through a structure), or send information for a system to interpret (even allowing remote control of a system using sound). The time reversal process allows one to focus energy to a specific location in space and to send a clean transmission of a selected signal only to that location. In order for the time reversal process to work, a calibration signal must be obtained. This signal may be obtained experimentally using an impulsive sound, a known chirp signal, or other known signals. It may also be determined from a numerical model of a known environment in which the focusing is desired or from passive listening over time to ambient noise.« less

46 CFR 131.535 - Firefighting training and drills.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Firefighting training and drills. 131.535 Section 131... OPERATIONS Tests, Drills, and Inspections § 131.535 Firefighting training and drills. (a) A fire drill must... drill, nor immediately before or after the abandon-ship drill. If none can be held on schedule, because...

30 CFR 56.7008 - Moving the drill.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Moving the drill. 56.7008 Section 56.7008... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7008 Moving the drill. When a drill is being moved from one drilling area to another...

76 FR 11757 - Drill Pipe From the People's Republic of China: Antidumping Duty Order

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-03

... are finished drill pipe and drill collars without regard to the specific chemistry of the steel (i.e... included are unfinished drill collars (including all drill collar green tubes) and unfinished drill pipe (including drill pipe green tubes, which are tubes meeting the following description: seamless tubes with an...

30 CFR 56.7008 - Moving the drill.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Moving the drill. 56.7008 Section 56.7008... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7008 Moving the drill. When a drill is being moved from one drilling area to another...

46 CFR 131.535 - Firefighting training and drills.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Firefighting training and drills. 131.535 Section 131... OPERATIONS Tests, Drills, and Inspections § 131.535 Firefighting training and drills. (a) A fire drill must... drill, nor immediately before or after the abandon-ship drill. If none can be held on schedule, because...

46 CFR 131.535 - Firefighting training and drills.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Firefighting training and drills. 131.535 Section 131... OPERATIONS Tests, Drills, and Inspections § 131.535 Firefighting training and drills. (a) A fire drill must... drill, nor immediately before or after the abandon-ship drill. If none can be held on schedule, because...

30 CFR 56.7008 - Moving the drill.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Moving the drill. 56.7008 Section 56.7008... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7008 Moving the drill. When a drill is being moved from one drilling area to another...

46 CFR 131.535 - Firefighting training and drills.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Firefighting training and drills. 131.535 Section 131... OPERATIONS Tests, Drills, and Inspections § 131.535 Firefighting training and drills. (a) A fire drill must... drill, nor immediately before or after the abandon-ship drill. If none can be held on schedule, because...

46 CFR 131.535 - Firefighting training and drills.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Firefighting training and drills. 131.535 Section 131... OPERATIONS Tests, Drills, and Inspections § 131.535 Firefighting training and drills. (a) A fire drill must... drill, nor immediately before or after the abandon-ship drill. If none can be held on schedule, because...

30 CFR 56.7008 - Moving the drill.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Moving the drill. 56.7008 Section 56.7008... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7008 Moving the drill. When a drill is being moved from one drilling area to another...

30 CFR 56.7008 - Moving the drill.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Moving the drill. 56.7008 Section 56.7008... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7008 Moving the drill. When a drill is being moved from one drilling area to another...

Drilling subsurface wellbores with cutting structures

DOEpatents

Mansure, Arthur James; Guimerans, Rosalvina Ramona

2010-11-30

A system for forming a wellbore includes a drill tubular. A drill bit is coupled to the drill tubular. One or more cutting structures are coupled to the drill tubular above the drill bit. The cutting structures remove at least a portion of formation that extends into the wellbore formed by the drill bit.

Cortical bone drilling: An experimental and numerical study.

PubMed

Alam, Khurshid; Bahadur, Issam M; Ahmed, Naseer

2014-12-16

Bone drilling is a common surgical procedure in orthopedics, dental and neurosurgeries. In conventional bone drilling process, the surgeon exerts a considerable amount of pressure to penetrate the drill into the bone tissue. Controlled penetration of drill in the bone is necessary for safe and efficient drilling. Development of a validated Finite Element (FE) model of cortical bone drilling. Drilling experiments were conducted on bovine cortical bone. The FE model of the bone drilling was based on mechanical properties obtained from literature data and additionally conducted microindentation tests on the cortical bone. The magnitude of stress in bone was found to decrease exponentially away from the lips of the drill in simulations. Feed rate was found to be the main influential factor affecting the force and torque in the numerical simulations and experiments. The drilling thrust force and torque were found to be unaffected by the drilling speed in numerical simulations. Simulated forces and torques were compared with experimental results for similar drilling conditions and were found in good agreement.CONCLUSIONS: FE schemes may be successfully applied to model complex kinematics of bone drilling process.

Technology Development and Field Trials of EGS Drilling Systems at Chocolate Mountain

DOE Data Explorer

Steven Knudsen

2012-01-01

Polycrystalline diamond compact (PDC) bits are routinely used in the oil and gas industry for drilling medium to hard rock but have not been adopted for geothermal drilling, largely due to past reliability issues and higher purchase costs. The Sandia Geothermal Research Department has recently completed a field demonstration of the applicability of advanced synthetic diamond drill bits for production geothermal drilling. Two commercially-available PDC bits were tested in a geothermal drilling program in the Chocolate Mountains in Southern California. These bits drilled the granitic formations with significantly better Rate of Penetration (ROP) and bit life than the roller cone bit they are compared with. Drilling records and bit performance data along with associated drilling cost savings are presented herein. The drilling trials have demonstrated PDC bit drilling technology has matured for applicability and improvements to geothermal drilling. This will be especially beneficial for development of Enhanced Geothermal Systems whereby resources can be accessed anywhere within the continental US by drilling to deep, hot resources in hard, basement rock formations.

Results from Testing of Two Rotary Percussive Drilling Systems

NASA Technical Reports Server (NTRS)

Kriechbaum, Kristopher; Brown, Kyle; Cady, Ian; von der Heydt, Max; Klein, Kerry; Kulczycki, Eric; Okon, Avi

2010-01-01

The developmental test program for the MSL (Mars Science Laboratory) rotary percussive drill examined the e ect of various drill input parameters on the drill pene- tration rate. Some of the input parameters tested were drill angle with respect to gravity and percussive impact energy. The suite of rocks tested ranged from a high strength basalt to soft Kaolinite clay. We developed a hole start routine to reduce high sideloads from bit walk. The ongoing development test program for the IMSAH (Integrated Mars Sample Acquisition and Handling) rotary percussive corer uses many of the same rocks as the MSL suite. An additional performance parameter is core integrity. The MSL development test drill and the IMSAH test drill use similar hardware to provide rotation and percussion. However, the MSL test drill uses external stabilizers, while the IMSAH test drill does not have external stabilization. In addition the IMSAH drill is a core drill, while the MSL drill uses a solid powdering bit. Results from the testing of these two related drilling systems is examined.

Potential for deep basin-centered gas accumulation in Hanna Basin, Wyoming

USGS Publications Warehouse

Wilson, Michael S.; Dyman, Thaddeus S.; Nuccio, Vito F.

2001-01-01

The potential for a continuous-type basin-centered gas accumulation in the Hanna Basin in Carbon County, Wyoming, is evaluated using geologic and production data including mud-weight, hydrocarbon-show, formation-test, bottom-hole-temperature, and vitrinite reflectance data from 29 exploratory wells. This limited data set supports the presence of a hypothetical basin-centered gas play in the Hanna Basin. Two generalized structural cross sections illustrate our interpretations of possible abnormally pressured compartments. Data indicate that a gas-charged, overpressured interval may occur within the Cretaceous Mowry, Frontier, and Niobrara Formations at depths below 10,000 ft along the southern and western margins of the basin. Overpressuring may also occur near the basin center within the Steele Shale and lower Mesaverde Group section at depths below 18,000 to 20,000 ft. However, the deepest wells drilled to date (12,000 to 15,300 ft) have not encountered over-pressure in the basin center. This overpressured zone is likely to be relatively small (probably 20 to 25 miles in diameter) and is probably depleted of gas near major basement reverse faults and outcrops where gas may have escaped. Water may have invaded reservoirs through outcrops and fracture zones along the basin margins, creating an extensive normally pressured zone. A zone of subnormal pressure also may exist below the water-saturated, normal-pressure zone and above the central zone of overpressure. Subnormal pressures have been interpreted in the center of the Hanna Basin at depths ranging from 10,000 to 25,000 ft based on indirect evidence including lost-circulation zones. Three wells on the south side of the basin, where the top of the subnormally pressured zone is interpreted to cut across stratigraphic boundaries, tested the Niobrara Formation and recovered gas and oil shows with very low shut-in pressures.

Evaluation of the parameters affecting bone temperature during drilling using a three-dimensional dynamic elastoplastic finite element model.

PubMed

Chen, Yung-Chuan; Tu, Yuan-Kun; Zhuang, Jun-Yan; Tsai, Yi-Jung; Yen, Cheng-Yo; Hsiao, Chih-Kun

2017-11-01

A three-dimensional dynamic elastoplastic finite element model was constructed and experimentally validated and was used to investigate the parameters which influence bone temperature during drilling, including the drill speed, feeding force, drill bit diameter, and bone density. Results showed the proposed three-dimensional dynamic elastoplastic finite element model can effectively simulate the temperature elevation during bone drilling. The bone temperature rise decreased with an increase in feeding force and drill speed, however, increased with the diameter of drill bit or bone density. The temperature distribution is significantly affected by the drilling duration; a lower drilling speed reduced the exposure duration, decreases the region of the thermally affected zone. The constructed model could be applied for analyzing the influence parameters during bone drilling to reduce the risk of thermal necrosis. It may provide important information for the design of drill bits and surgical drilling powers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whelan, J.A.

During the summer of 1975, the Department of Geology and Geophysics drilled nine drill thermal gradient/heat flow holes. Total footage drilled was 2125 feet. Seven holes were drilled with a Mayhew 1000 drill using various combinations of down the hole hammer drilling, rotary drilling, and NX diamond core drilling. Three of these were heat flow holes--one in the Mineral Range, one in the Tushar Range near Beaver, Utah, and one near Monroe, Utah. Two were alteration study holes in the Roosevelt KGRA and two were temperature gradient holes, in alluvium in the Roosevelt KGRA. The average depth of the holesmore » drilled with the Mayhew 1000 drill was 247 feet. Holes ranged from 135 feet to 492 feet. Cost per foot averaged $18.53. Two holes were core drilled with a Joy 12, BX-size drill. One was to 75 feet, in perlite. This hole was abandoned. The other was to 323 feet in granite.« less

A cadaveric study of bone tissue temperature during pin site drilling utilizing fluoroptic thermography.

PubMed

Muffly, Matthew; Winegar, Corbett; Miller, Mark Carl; Altman, Gregory

2018-05-03

Using fluoroptic thermography, temperature was measured during pin site drilling of intact cortical human cadaver bone with a combination of one-step drilling, graduated drilling, and one-step drilling with irrigation of 5.0 mm Schanz pins. A 1440 rpm constant force drilling was used to on tibial diaphyses while a sensor probe placed 0.5 mm adjacent to the drill hole measured temperature. Four drilling techniques on each of the tibial segments were performed: 3.5mm drill bit, 5.0mm Schanz pin, 5.0 mm Schanz pin in 3.5 mm pre-drilled entry site, 5.0 mm Schanz pin utilizing irrigation. One-step drilling using a 5.0 mm Schanz pin without irrigation produced a temperature that exceeded the threshold temperature for heat-induced injury in 5 of the 8 trials. With the other three drilling techniques, only one in24 trials produced a temperature that would result in thermal injury. This difference was found to be statistically significant (p = 0.003). The use of irrigation significantly reduced the maximum bone tissue temperature in one-step drilling of a 5.0 mm Schanz pin (p = 0.02). One-step drilling with a 3.5 mm drill bit achieved maximum temperature significantly faster than graduated drilling and drilling with irrigation using a 5.0 mm Schanz pin (p <0.01). One-step drilling with a 5.0 mm Schanz pin into cortical bone can produce temperatures that can lead to heat-induced injury. Irrigation alone can reduce the temperatures sufficiently to avoid damage. Pre-drilling can increase temperatures significantly but the extent of any injury should be small.

Tectonic evolution of the outer Izu-Bonin-Mariana fore arc system: initial results from IODP Expedition 352

NASA Astrophysics Data System (ADS)

Kurz, W.; Ferre, E. C.; Robertson, A. H. F.; Avery, A. J.; Kutterolf, S.

2015-12-01

During International Ocean Discovery Program (IODP) Expedition 352, a section through the volcanic stratigraphy of the outer fore arc of the Izu-Bonin-Mariana (IBM) system was drilled to trace magmatism, tectonics, and crustal accretion associated with subduction initiation. Structures within drill cores, borehole and site survey seismic data indicate that tectonic deformation in the outer IBM fore arc is mainly post-magmatic. Extension generated asymmetric sediment basins such as half-grabens at sites 352-U1439 and 352-U1442 on the upper trench slope. Along their eastern margins the basins are bounded by west-dipping normal faults. Deformation was localized along multiple sets of faults, accompanied by syn-tectonic pelagic and volcaniclastic sedimentation. The lowermost sedimentary units were tilted eastward by ~20°. Tilted beds were covered by sub-horizontal beds. Biostratigraphic constraints reveal a minimum age of the oldest sediments at ~ 35 Ma; timing of the sedimentary unconformities is between ~ 27 and 32 Ma. At sites 352-U1440 and 352-U1441 on the outer fore arc strike-slip faults are bounding sediment basins. Sediments were not significantly affected by tectonic tilting. Biostratigraphy gives a minimum age of the basement-cover contact between ~29.5 and 32 Ma. The post-magmatic structures reveal a multiphase tectonic evolution of the outer IBM fore arc. At sites 352-U1439 and 352-U1442, shear with dominant reverse to oblique reverse displacement was localized along subhorizontal fault zones, steep slickensides and shear fractures. These were either re-activated as or cut by normal-faults and strike-slip faults. Extension was also accommodated by steep to subvertical mineralized veins and extensional fractures. Faults at sites 352-U1440 and 352-U1441 show mainly strike-slip kinematics. Sediments overlying the igneous basement(maximum Late Eocene to Recent age), document ash and aeolian input, together with mass wasting of the fault-bounded sediment ponds.

Determining gas hydrate distribution in sands using integrated analysis of well log and seismic data in the Terrebonne Basin, Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hillman, Jess; Cook, Ann; Daigle, Hugh

The Terrebonne Basin is a salt bounded mini-basin in the northeast section of the Walker Ridge protraction area in the Gulf of Mexico, and the main site for an upcoming gas-hydrate focused International Ocean Discovery Program (IODP) cruise. The basin is infilled by an increasingly mud rich sedimentary sequence with several 5-15 meter gas-hydrate filled sand units of Miocene to Pliocene age overlying the up-domed salt. These gas-hydrate filled sand units can be identified in logging while drilling data from two existing wells in the Terrebonne Basin, drilled in 2009 by the Gas Hydrate Joint Industry Project (JIP) Leg 2.more » The sand units are cross cut by a distinct bottom-simulating reflector (BSR), and are clearly characterized by a polarity reversal in the sand units. The polarity reversal is caused by a positive gas-hydrate filled sand within the stability zone changing to negative gas-bearing sand. Using well data and calculated synthetic seismogram well ties we are able to identify several additional 1-4 meter gas-hydrate and water-saturated sand units associated with thick (100-200 m-thick), fine grained, hydrate bearing fractured units in the upper sedimentary sequence on the seismic data. Following on previous work, we propose that microbial generation of methane occurring within the fine-grained, fractured units acts as a source for gas hydrate formation in the thin sands. In contrast, it has been proposed that the gas hydrate in the 5-15 m-thick sands first discovered by the JIP was originates from a deeper thermogenic source. Through correlating hydrate occurrence in sands from well data, to amplitudes derived from the seismic data, we can estimate possible distribution of hydrate across the basin. Overall, we find the Terrebonne basin to be a complex gas hydrate system with multiple mechanisms of methane generation and migration.« less

Drilling, Completion, and Data Collection Plans An Assessment of Geological Carbon Sequestration Options in the Illinois Basin: Phase III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malkewicz, Nicholas; Kirksey, Jim; Finley, Robert

2015-05-01

Executive Summary The Illinois Basin – Decatur Project (IBDP) is managed by the Midwest Geological Sequestration Consortium (MGSC) and is led by the Illinois State Geological Survey (ISGS) at the University of Illinois. The project site is located on the Archer Daniels Midland Company (ADM) property in Decatur, Illinois, and is a fully integrated carbon capture and storage (CCS) project that uses CO₂ captured from the ethanol-producing fermentation process at the ADM corn-processing plant (Finley et. al., 2013). IBDP has a goal of injecting one million tonnes of CO₂ into the basal sands of the Mt. Simon Sandstone over amore » three-year period. This is a multifaceted project, and this report details the planning and results of the drilling, completions, well testing, log data acquisition, and the Health, Safety, and Environment (HSE) aspects of the project. Three deep wells were planned for the IBDP: • The injection well: Injection Well #1 (CCS1); • The monitoring well (both in-zone and above seal): Verification Well #1 (VW1); and • The geophone monitoring well: Geophysical Monitoring Well #1 (GM1). The detailed plans for these wells are attached to the appendices of this document. The wells were drilled successfully with little deviation from the original plans. The biggest change from the plan to execution was the need to adjust for larger-than-expected loss of circulation in the Potosi section of the Knox Formation. The completions reports also attached to this document detail the well constructions as they were actually built. Injectivity testing was carried out, and the perforating plans were adjusted based on the results. Additional perforations and acidizing were performed as a result of the injectivity testing. The testing plans are detailed in this report along with the actual testing results. The injectivity testing results were used in the modeling and simulation efforts. Detailed HSE plans were developed and implemented during the planning and execution phases of the project. The implementation included an HSE Bridging Document, which served to unify the HSE policies of the project partners and key subcontractors. The HSE plan and actual HSE results are presented in this document. There were no recordable HSE incidents during the project. A detailed logging program was developed based on project needs. The log data were acquired in accordance with the plan, and both the plan and log results are presented in this report. Log data were heavily utilized by the research staff, modelers, reservoir engineers, and for technical and permitting efforts. 5 Several key lessons were learned during the project: • Safety in operations and execution is paramount and is only achieved through proper planning and behavior control. The certainty of this was reinforced through implementation of this lesson and the resultant flawless HSE performance during the project. • Losses of drilling fluid circulation were larger than anticipated within the Potosi Formation. Circulation was only recovered through cementing the loss zones. • When possible, minimizing complexity in permit requirements and well designs is preferable. • The size of the wells were outside of the standard experience and expertise typical within the basin, and therefore required substantial planning and ramp-up of contractors and partners to meet project objectives. • With multiple stakeholders and research partners, establishing objectives and requirements early and adhering to change request procedures throughout the project are critical to manage competing data and sampling objectives that may be detrimental to overall progress. The well construction and completion operations were successfully executed, with all wells built in a manner that achieved excellent wellbore integrity. Log planning involved a number of stakeholders and technical specialists. Data collection from logging, coring, and testing was excellent. Time and effort spent with the associated contractors and suppliers to develop a well plan beyond normal scope proved highly successful, resulting in a well-construction and completion project that surpassed expectations. The world-class HSE results also demonstrate the commitment of all stakeholders in the project. The details follow in the body of this document« less

Optical microangiography enabling visualization of change in meninges after traumatic brain injury in mice in vivo

NASA Astrophysics Data System (ADS)

Choi, Woo June; Qin, Wan; Qi, Xiaoli; Wang, Ruikang K.

2016-03-01

Traumatic brain injury (TBI) is a form of brain injury caused by sudden impact on brain by an external mechanical force. Following the damage caused at the moment of injury, TBI influences pathophysiology in the brain that takes place within the minutes or hours involving alterations in the brain tissue morphology, cerebral blood flow (CBF), and pressure within skull, which become important contributors to morbidity after TBI. While many studies for the TBI pathophysiology have been investigated with brain cortex, the effect of trauma on intracranial tissues has been poorly studied. Here, we report use of high-resolution optical microangiography (OMAG) to monitor the changes in cranial meninges beneath the skull of mouse after TBI. TBI is induced on a brain of anesthetized mouse by thinning the skull using a soft drill where a series of drilling exert mechanical stress on the brain through the skull, resulting in mild brain injury. Intracranial OMAG imaging of the injured mouse brain during post-TBI phase shows interesting pathophysiological findings in the meningeal layers such as widening of subdural space as well as vasodilation of subarachnoid vessels. These processes are acute and reversible within hours. The results indicate potential of OMAG to explore mechanism involved following TBI on small animals in vivo.

Temporal bone borehole accuracy for cochlear implantation influenced by drilling strategy: an in vitro study.

PubMed

Kobler, Jan-Philipp; Schoppe, Michael; Lexow, G Jakob; Rau, Thomas S; Majdani, Omid; Kahrs, Lüder A; Ortmaier, Tobias

2014-11-01

Minimally invasive cochlear implantation is a surgical technique which requires drilling a canal from the mastoid surface toward the basal turn of the cochlea. The choice of an appropriate drilling strategy is hypothesized to have significant influence on the achievable targeting accuracy. Therefore, a method is presented to analyze the contribution of the drilling process and drilling tool to the targeting error isolated from other error sources. The experimental setup to evaluate the borehole accuracy comprises a drill handpiece attached to a linear slide as well as a highly accurate coordinate measuring machine (CMM). Based on the specific requirements of the minimally invasive cochlear access, three drilling strategies, mainly characterized by different drill tools, are derived. The strategies are evaluated by drilling into synthetic temporal bone substitutes containing air-filled cavities to simulate mastoid cells. Deviations from the desired drill trajectories are determined based on measurements using the CMM. Using the experimental setup, a total of 144 holes were drilled for accuracy evaluation. Errors resulting from the drilling process depend on the specific geometry of the tool as well as the angle at which the drill contacts the bone surface. Furthermore, there is a risk of the drill bit deflecting due to synthetic mastoid cells. A single-flute gun drill combined with a pilot drill of the same diameter provided the best results for simulated minimally invasive cochlear implantation, based on an experimental method that may be used for testing further drilling process improvements.

DAME: planetary-prototype drilling automation.

PubMed

Glass, B; Cannon, H; Branson, M; Hanagud, S; Paulsen, G

2008-06-01

We describe results from the Drilling Automation for Mars Exploration (DAME) project, including those of the summer 2006 tests from an Arctic analog site. The drill hardware is a hardened, evolved version of the Advanced Deep Drill by Honeybee Robotics. DAME has developed diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The DAME drill automation tested from 2004 through 2006 included adaptively controlled drilling operations and the downhole diagnosis of drilling faults. It also included dynamic recovery capabilities when unexpected failures or drilling conditions were discovered. DAME has developed and tested drill automation software and hardware under stressful operating conditions during its Arctic field testing campaigns at a Mars analog site.

DAME: Planetary-Prototype Drilling Automation

NASA Astrophysics Data System (ADS)

Glass, B.; Cannon, H.; Branson, M.; Hanagud, S.; Paulsen, G.

2008-06-01

We describe results from the Drilling Automation for Mars Exploration (DAME) project, including those of the summer 2006 tests from an Arctic analog site. The drill hardware is a hardened, evolved version of the Advanced Deep Drill by Honeybee Robotics. DAME has developed diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The DAME drill automation tested from 2004 through 2006 included adaptively controlled drilling operations and the downhole diagnosis of drilling faults. It also included dynamic recovery capabilities when unexpected failures or drilling conditions were discovered. DAME has developed and tested drill automation software and hardware under stressful operating conditions during its Arctic field testing campaigns at a Mars analog site.

Nanotechnology for Synthetic High Density Lipoproteins

PubMed Central

Luthi, Andrea J.; Patel, Pinal C.; Ko, Caroline H.; Mutharasan, R. Kannan; Mirkin, Chad A.; Thaxton, C. Shad

2014-01-01

Atherosclerosis is the disease mechanism responsible for coronary heart disease (CHD), the leading cause of death worldwide. One strategy to combat atherosclerosis is to increase the amount of circulating high density lipoproteins (HDL), which transport cholesterol from peripheral tissues to the liver for excretion. The process, known as reverse cholesterol transport, is thought to be one of the main reasons for the significant inverse correlation observed between HDL blood levels and the development of CHD. This article highlights the most common strategies for treating atherosclerosis using HDL. We further detail potential treatment opportunities that utilize nanotechnology to increase the amount of HDL in circulation. The synthesis of biomimetic HDL nanostructures that replicate the chemical and physical properties of natural HDL provides novel materials for investigating the structure-function relationships of HDL and for potential new therapeutics to combat CHD. PMID:21087901

The aerodynamics of circulation control

NASA Technical Reports Server (NTRS)

Wood, N. J.

1981-01-01

Two dimensional subsonic wind tunnel tests were conducted on a 20% thickness: chord ratio circulation controlled elliptic aerofoil section equipped with forward and reverse blowing slots. Overall performance measurements were made over a range of trailing edge blowing momentum coefficients from 0 to 0.04; some included the effect of leading edge blowing. A detailed investigation of the trailing edge wall jet, using split film probes, hot wire probes and total head tubes, provided measurements of mean velocity components, Reynolds normal and shear stresses, and radial static pressure. The closure of the two dimensional angular momentum and continuity equations was examined using the measured data, with and without correction, and the difficulty of obtaining a satisfactory solution illustrated. Suggestions regarding the nature of the flow field which should aid the understanding of Coanda effect and the theoretical solution of highly curved wall jet flows are presented.

Process control strategy for ITER central solenoid operation

NASA Astrophysics Data System (ADS)

Maekawa, R.; Takami, S.; Iwamoto, A.; Chang, H.-S.; Forgeas, A.; Chalifour, M.

2016-12-01

ITER Central Solenoid (CS) pulse operation induces significant flow disturbance in the forced-flow Supercritical Helium (SHe) cooling circuit, which could impact primarily on the operation of cold circulator (SHe centrifugal pump) in Auxiliary Cold Box (ACB). Numerical studies using Venecia®, SUPERMAGNET and 4C have identified reverse flow at the CS module inlet due to the substantial thermal energy deposition at the inner-most winding. To assess the reliable operation of ACB-CS (dedicated ACB for CS), the process analyses have been conducted with a dynamic process simulation model developed by Cryogenic Process REal-time SimulaTor (C-PREST). As implementing process control of hydrodynamic instability, several strategies have been applied to evaluate their feasibility. The paper discusses control strategy to protect the centrifugal type cold circulator/compressor operations and its impact on the CS cooling.

The balance of kinetic and total energy simulated by the OSU two-level atmospheric general circulation model for January and July

NASA Technical Reports Server (NTRS)

Wang, J.-T.; Gates, W. L.; Kim, J.-W.

1984-01-01

A three-year simulation which prescribes seasonally varying solar radiation and sea surface temperature is the basis of the present study of the horizontal structure of the balances of kinetic and total energy simulated by Oregon State University's two-level atmospheric general circulation model. Mechanisms responsible for the local energy changes are identified, and the energy balance requirement's fulfilment is examined. In January, the vertical integral of the total energy shows large amounts of external heating over the North Pacific and Atlantic, together with cooling over most of the land area of the Northern Hemisphere. In July, an overall seasonal reversal is found. Both seasons are also characterized by strong energy flux divergence in the tropics, in association with the poleward transport of heat and momentum.

Effects of implant drilling parameters for pilot and twist drills on temperature rise in bone analog and alveolar bones.

PubMed

Chen, Yung-Chuan; Hsiao, Chih-Kun; Ciou, Ji-Sih; Tsai, Yi-Jung; Tu, Yuan-Kun

2016-11-01

This study concerns the effects of different drilling parameters of pilot drills and twist drills on the temperature rise of alveolar bones during dental implant procedures. The drilling parameters studied here include the feed rate and rotation speed of the drill. The bone temperature distribution was analyzed through experiments and numerical simulations of the drilling process. In this study, a three dimensional (3D) elasto-plastic dynamic finite element model (DFEM) was proposed to investigate the effects of drilling parameters on the bone temperature rise. In addition, the FE model is validated with drilling experiments on artificial human bones and porcine alveolar bones. The results indicate that 3D DFEM can effectively simulate the bone temperature rise during the drilling process. During the drilling process with pilot drills or twist drills, the maximum bone temperature occurred in the region of the cancellous bones close to the cortical bones. The feed rate was one of the important factors affecting the time when the maximum bone temperature occurred. Our results also demonstrate that the elevation of bone temperature was reduced as the feed rate increased and the drill speed decreased, which also effectively reduced the risk region of osteonecrosis. These findings can serve as a reference for dentists in choosing drilling parameters for dental implant surgeries. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Oil Based Drilling Fluid Waste: An Overview on Environmentally Persistent Pollutants

NASA Astrophysics Data System (ADS)

Siddique, Shohel; Kwoffie, Lorraine; Addae-Afoakwa, Kofi; Yates, Kyari; Njuguna, James

2017-05-01

Operational discharges of spent drilling fluid, produced water, and accumulated drill cuttings from oil and gas industry are a continuous point source of environmental pollution. To meet the strict environmental standard for waste disposal, oil and gas industry is facing a numerous challenges in technological development to ensure a clean and safe environment. Oil and gas industry generates a large amount of spent drilling fluid, produced water, and drill cuttings, which are very different in every drilling operation in terms of composition and characterisation. This review article highlights the knowledge gap in identifying the different sources of waste streams in combined drilling waste. This paper also emphasises how different chemicals turn into environmentally significant pollutants after serving great performance in oil and gas drilling operations. For instance, oil based drilling fluid performs excellent in deeper drilling and drilling in the harsh geological conditions, but ended with (produces) a significant amount of persistent toxic pollutants in the environment. This review paper provides an overview on the basic concepts of drilling fluids and their functions, sources and characterisation of drilling wastes, and highlights some environmentally significant elements including different minerals present in drilling waste stream.

A monsoon-like Southwest Australian circulation and its relation with rainfall in Southwest Western Australia

NASA Astrophysics Data System (ADS)

Feng, Juan; Li, Jianping; Li, Yun

2010-05-01

Using the NCEP/NCAR, ERA-40 reanalysis, and precipitation data from CMAP and Australian Bureau of Meteorology, the variability and circulation features influencing the southwest Western Australia (SWWA) winter rainfall are investigated. It is found that the climate of southwest Australia bears a strong seasonality in the annual cycle and exhibits a monsoon-like atmospheric circulation, which is termed as the southwest Australian circulation (SWAC) for its several distinct features characterizing a monsoonal circulation: the seasonal reversal of winds, alternate wet and dry seasons, and an evident land-sea thermal contrast. The seasonal march of the SWAC in extended winter (May to October) is demonstrated by pentad data. An index based on the dynamics normalized seasonality was introduced to describe the behavior and variation of the winter SWAC. It is found that the winter rainfall over SWWA has a significant positive correlation with the SWAC index in both early (May to July) and late (August to October) winter. In weaker winter SWAC years there is an anti-cyclonic anomaly over southern Indian Ocean resulting in weaker westerlies and northerlies which are not favorable for more rainfall over SWWA, and the opposite combination is true in the stronger winter SWAC years. The SWAC explains not only a large portion of the interannual variability of SWWA rainfall in both early and late winter, but also the long term drying trend over SWWA in early winter. The well-coupled SWAC-SWWA rainfall relationship seems to be largely independent of the well-known effects of large-scale atmospheric circulations such as the Southern Hemisphere Annular Mode (SAM), El Niño/Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and ENSO Modoki (EM). The result offers qualified support for the argument that the monsoon-like circulation may contribute to the rainfall decline in early winter over SWWA.

Increased traffic accident rates associated with shale gas drilling in Pennsylvania.

PubMed

Graham, Jove; Irving, Jennifer; Tang, Xiaoqin; Sellers, Stephen; Crisp, Joshua; Horwitz, Daniel; Muehlenbachs, Lucija; Krupnick, Alan; Carey, David

2015-01-01

We examined the association between shale gas drilling and motor vehicle accident rates in Pennsylvania. Using publicly available data on all reported vehicle crashes in Pennsylvania, we compared accident rates in counties with and without shale gas drilling, in periods with and without intermittent drilling (using data from 2005 to 2012). Counties with drilling were matched to non-drilling counties with similar population and traffic in the pre-drilling period. Heavily drilled counties in the north experienced 15-23% higher vehicle crash rates in 2010-2012 and 61-65% higher heavy truck crash rates in 2011-2012 than control counties. We estimated 5-23% increases in crash rates when comparing months with drilling and months without, but did not find significant effects on fatalities and major injury crashes. Heavily drilled counties in the southwest showed 45-47% higher rates of fatal and major injury crashes in 2012 than control counties, but monthly comparisons of drilling activity showed no significant differences associated with drilling. Vehicle accidents have measurably increased in conjunction with shale gas drilling. Copyright © 2014. Published by Elsevier Ltd.

Study on the influence of parameters of medical drill on bone drilling temperature

NASA Astrophysics Data System (ADS)

XU, Xianchun; Hu, Yahui; Han, Jingwang; Yue, Lin; Jiang, Wangbiao

2018-03-01

During surgical interventions, the temperature generated during cortical bone drilling can affect the activity of bone material, which may lead to necrosis. In this paper, with the purpose of reducing the temperature during cortical bone drilling, the influence of the parameters of medical drill were analyzed. The finite element model of the drilling process was established based on the parametric design of the dril. The relationship between the drill bit diameter, the point angle, and the helix angle to the drilling temperature was studied by the center composite experiment. The results showed that the drilling temperature is increased with the increase of drill diameter, vertex angle and helix angle in the range of certain research.

Effect of pre-drilling on intraosseous temperature during self-drilling mini-implant placement in a porcine mandible model.

PubMed

Gurdán, Zsuzsanna; Vajta, László; Tóth, Ákos; Lempel, Edina; Joób-Fancsaly, Árpád; Szalma, József

2017-03-31

This in vitro study investigated intraos seous heat production during insertion, with and without pre-drilling, of a self-drilling orthodontic mini-implant. To measure temperature changes and drilling times in pig ribs, a special testing apparatus was used to examine new and worn pre-drills at different speeds. Temperatures were measured during mini-implant placement with and without pre-drilling. The average intraosseous temperature increase during manual mini-implant insertion was similar with and without pre-drilling (11.8 ± 2.1°C vs. 11.3 ± 2.4°C, respectively; P = 0.707). During pre-drilling the mean temperature increase for new drills was 2.1°C at 100 rpm, 2.3°C at 200 rpm, and 7.6°C at 1,200 rpm. Temperature increases were significantly higher for worn drills at the same speeds (2.98°C, 3.0°C, and 12.3°C, respectively), while bone temperatures at 100 and 200 rpm were similar for new and worn drills (P = 0.345 and 0.736, respectively). Baseline bone temperature was approximated within 30 s after drilling in most specimens. Drilling time at 100 rpm was 2.1 ± 0.9 s, but was significantly shorter at 200 rpm (1.1 ± 0.2 s) and 1,200 rpm (0.1 ± 0.03 s). Pre-drilling did not decrease intraosseous temperatures. In patients for whom pre-drilling is indicated, speeds of 100 or 200 rpm are recommended, at least 30 s after pilot drilling.

Heat accumulation during sequential cortical bone drilling.

PubMed

Palmisano, Andrew C; Tai, Bruce L; Belmont, Barry; Irwin, Todd A; Shih, Albert; Holmes, James R

2016-03-01

Significant research exists regarding heat production during single-hole bone drilling. No published data exist regarding repetitive sequential drilling. This study elucidates the phenomenon of heat accumulation for sequential drilling with both Kirschner wires (K wires) and standard two-flute twist drills. It was hypothesized that cumulative heat would result in a higher temperature with each subsequent drill pass. Nine holes in a 3 × 3 array were drilled sequentially on moistened cadaveric tibia bone kept at body temperature (about 37 °C). Four thermocouples were placed at the center of four adjacent holes and 2 mm below the surface. A battery-driven hand drill guided by a servo-controlled motion system was used. Six samples were drilled with each tool (2.0 mm K wire and 2.0 and 2.5 mm standard drills). K wire drilling increased temperature from 5 °C at the first hole to 20 °C at holes 6 through 9. A similar trend was found in standard drills with less significant increments. The maximum temperatures of both tools increased from <0.5 °C to nearly 13 °C. The difference between drill sizes was found to be insignificant (P > 0.05). In conclusion, heat accumulated during sequential drilling, with size difference being insignificant. K wire produced more heat than its twist-drill counterparts. This study has demonstrated the heat accumulation phenomenon and its significant effect on temperature. Maximizing the drilling field and reducing the number of drill passes may decrease bone injury. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Robotic and Human-Tended Collaborative Drilling Automation for Subsurface Exploration

NASA Technical Reports Server (NTRS)

Glass, Brian; Cannon, Howard; Stoker, Carol; Davis, Kiel

2005-01-01

Future in-situ lunar/martian resource utilization and characterization, as well as the scientific search for life on Mars, will require access to the subsurface and hence drilling. Drilling on Earth is hard - an art form more than an engineering discipline. Human operators listen and feel drill string vibrations coming from kilometers underground. Abundant mass and energy make it possible for terrestrial drilling to employ brute-force approaches to failure recovery and system performance issues. Space drilling will require intelligent and autonomous systems for robotic exploration and to support human exploration. Eventual in-situ resource utilization will require deep drilling with probable human-tended operation of large-bore drills, but initial lunar subsurface exploration and near-term ISRU will be accomplished with lightweight, rover-deployable or standalone drills capable of penetrating a few tens of meters in depth. These lightweight exploration drills have a direct counterpart in terrestrial prospecting and ore-body location, and will be designed to operate either human-tended or automated. NASA and industry now are acquiring experience in developing and building low-mass automated planetary prototype drills to design and build a pre-flight lunar prototype targeted for 2011-12 flight opportunities. A successful system will include development of drilling hardware, and automated control software to operate it safely and effectively. This includes control of the drilling hardware, state estimation of both the hardware and the lithography being drilled and state of the hole, and potentially planning and scheduling software suitable for uncertain situations such as drilling. Given that Humans on the Moon or Mars are unlikely to be able to spend protracted EVA periods at a drill site, both human-tended and robotic access to planetary subsurfaces will require some degree of standalone, autonomous drilling capability. Human-robotic coordination will be important, either between a robotic drill and humans on Earth, or a human-tended drill and its visiting crew. The Mars Analog Rio Tinto Experiment (MARTE) is a current project that studies and simulates the remote science operations between an automated drill in Spain and a distant, distributed human science team. The Drilling Automation for Mars Exploration (DAME) project, by contrast: is developing and testing standalone automation at a lunar/martian impact crater analog site in Arctic Canada. The drill hardware in both projects is a hardened, evolved version of the Advanced Deep Drill (ADD) developed by Honeybee Robotics for the Mars Subsurface Program. The current ADD is capable of 20m, and the DAME project is developing diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The current drill automation architecture being developed by NASA and tested in 2004-06 at analog sites in the Arctic and Spain will add downhole diagnosis of different strata, bit wear detection, and dynamic replanning capabilities when unexpected failures or drilling conditions are discovered in conjunction with simulated mission operations and remote science planning. The most important determinant of future 1unar and martian drilling automation and staffing requirements will be the actual performance of automated prototype drilling hardware systems in field trials in simulated mission operations. It is difficult to accurately predict the level of automation and human interaction that will be needed for a lunar-deployed drill without first having extensive experience with the robotic control of prototype drill systems under realistic analog field conditions. Drill-specific failure modes and software design flaws will become most apparent at this stage. DAME will develop and test drill automation software and hardware under stressful operating conditions during several planned field campaigns. Initial results from summer 2004 tests show seven identifi distinct failure modes of the drill: cuttings-removal issues with low-power drilling into permafrost, and successful steps at executive control and initial automation.

Combination drilling and skiving tool

DOEpatents

Stone, William J.

1989-01-01

A combination drilling and skiving tool including a longitudinally extending hollow skiving sleeve slidably and concentrically mounted on a right-handed twist drill. Dogs or pawls provided on the internal periphery of the skiving sleeve engage with the helical grooves of the drill. During a clockwise rotation of the tool, the drill moves downwardly and the sleeve translates upwardly, so that the drill performs a drilling operation on a workpiece. On the other hand, the drill moves upwardly and the sleeve translates downwardly, when the tool is rotated in a counter-clockwise direction, and the sleeve performs a skiving operation. The drilling and skiving operations are separate, independent and exclusive of each other.

While drilling system and method

DOEpatents

Mayes, James C.; Araya, Mario A.; Thorp, Richard Edward

2007-02-20

A while drilling system and method for determining downhole parameters is provided. The system includes a retrievable while drilling tool positionable in a downhole drilling tool, a sensor chassis and at least one sensor. The while drilling tool is positionable in the downhole drilling tool and has a first communication coupler at an end thereof. The sensor chassis is supported in the drilling tool. The sensor chassis has a second communication coupler at an end thereof for operative connection with the first communication coupler. The sensor is positioned in the chassis and is adapted to measure internal and/or external parameters of the drilling tool. The sensor is operatively connected to the while drilling tool via the communication coupler for communication therebetween. The sensor may be positioned in the while drilling tool and retrievable with the drilling tool. Preferably, the system is operable in high temperature and high pressure conditions.

30 CFR 57.7052 - Drilling positions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

30 CFR 57.7052 - Drilling positions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

30 CFR 57.7052 - Drilling positions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

30 CFR 57.7052 - Drilling positions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

30 CFR 57.7052 - Drilling positions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

Slow drilling speeds for single-drill implant bed preparation. Experimental in vitro study.

PubMed

Delgado-Ruiz, R A; Velasco Ortega, E; Romanos, G E; Gerhke, S; Newen, I; Calvo-Guirado, J L

2018-01-01

To evaluate the real-time bone temperature changes during the preparation of the implant bed with a single-drill protocol with different drill designs and different slow drilling speeds in artificial type IV bone. For this experimental in vitro study, 600 implant bed preparations were performed in 10 bovine bone disks using three test slow drilling speeds (50/150/300 rpm) and a control drilling speed (1200 rpm). The temperature at crestal and apical areas and time variations produced during drilling with three different drill designs with similar diameter and length but different geometry were recorded with real-life thermographic analysis. Statistical analysis was performed by two-way analysis of variance. Multiple comparisons of temperatures and time with the different drill designs and speeds were performed with the Tukey's test. T Max values for the control drilling speed with all the drill designs (D1 + 1200; D2 + 1200; D3 + 1200) were higher compared to those for the controls for 11 ± 1.32 °C (p < 0.05). The comparison of T Max within the test groups showed that drilling at 50 rpm resulted in the lowest temperature increment (22.11 ± 0.8 °C) compared to the other slow drilling speeds of 150 (24.752 ± 1.1 °C) and 300 rpm (25.977 ± 1.2 °C) (p < 0.042). Temperature behavior at crestal and apical areas was similar being lower for slow drilling speeds compared to that for the control drilling speed. Slow drilling speeds required significantly more time to finish the preparation of the implant bed shown as follows: 50 rpm > 150 rpm > 300 rpm > control (p < 0.05). A single-drill protocol with slow drilling speeds (50, 150, and 300 rpm) without irrigation in type IV bone increases the temperature at the coronal and apical levels but is below the critical threshold of 47 °C. The drill design in single-drill protocols using slow speeds (50, 150, and 300 rpm) does not have an influence on the thermal variations. The time to accomplish the implant bed preparation with a single-drill protocol in type IV bone is influenced by the drilling speed and not by the drill design. As the speed decreases, then more time is required.

Transitional Boundary Layers Under the Influence of High Free Stream Turbulence, Intensive Wall Cooling and High Pressure Gradients in Hot Gas Circulation. Ph.D. Thesis - Technische Hochschule, Karlsruhe, 1985

NASA Technical Reports Server (NTRS)

Rued, Klaus

1987-01-01

The requirements for fundamental experimental studies of the influence of free stream turbulence, pressure gradients and wall cooling are discussed. Under turbine-like free stream conditions, comprehensive tests of transitional boundary layers with laminar, reversing and turbulent flow increments were performed to decouple the effects of the parameters and to determine the effects during mutual interaction.

PERK eIF2alpha kinase regulates neonatal growth by controlling the expression of circulating insulin-like growth factor-I derived from the liver.

PubMed

Li, Yulin; Iida, Kaori; O'Neil, Jeff; Zhang, Peichuan; Li, Sheng'ai; Frank, Ami; Gabai, Aryn; Zambito, Frank; Liang, Shun-Hsin; Rosen, Clifford J; Cavener, Douglas R

2003-08-01

Humans afflicted with the Wolcott-Rallison syndrome and mice deficient for PERK (pancreatic endoplasmic reticulum eIF2alpha kinase) show severe postnatal growth retardation. In mice, growth retardation in Perk-/- mutants is manifested within the first few days of neonatal development. Growth parameters of Perk-/- mice, including comparison of body weight to length and organ weights, are consistent with proportional dwarfism. Tibia growth plates exhibited a reduction in proliferative and hypertrophic chondrocytes underlying the longitudinal growth retardation. Neonatal Perk-/- deficient mice show a 75% reduction in liver IGF-I mRNA and serum IGF-I within the first week, whereas the expression of IGF-I mRNA in most other tissues is normal. Injections of IGF-I partially reversed the growth retardation of the Perk-/- mice, whereas GH had no effect. Transgenic rescue of PERK activity in the insulin- secreting beta-cells of the Perk-/- mice reversed the juvenile but not the neonatal growth retardation. We provide evidence that circulating IGF-I is derived from neonatal liver but is independent of GH at this stage. We propose that PERK is required to regulate the expression of IGF-I in the liver during the neonatal period, when IGF-I expression is GH-independent, and that the lack of this regulation results in severe neonatal growth retardation.

Effects of a drill diameter on the temperature rise in a bone during implant site preparation under clinical conditions.

PubMed

Bogovič, Valerija; Svete, Andrej; Bajsić, Ivan

2016-10-01

Heat, generated during the drilling of a dental implant site preparation, leads to a temperature rise and consequently to a thermal injury of the bone tissue surrounding the implant site, which can cause the subsequent implant failure. In this article, we present new findings related to the temperature rise during implant site drilling under real conditions on a bovine rib bone specimen. The experiments were designed with the help of a full-factorial design in randomized complete blocks, where the main effects of the drill diameter in combination with the drilling force and the drilling speed, and their interactions, on the temperature rise were determined. The temperature rise in the bone under real conditions was measured as the implant site was being prepared by a dentist using intermittent, graduated drilling and external irrigation. Results show that the drill diameter has statistically significant effect, independent of the drilling procedure used. Among the examined drilling parameters, the drill diameter has the greatest effect, where an increase in the drill diameter first causes a decrease in the temperature rise and further increase in the drill diameter causes its increase. During the continuous and one-step drilling, the temperatures of the bones were up to 40.5 °C and during the drilling under actual conditions up to 30.11 °C. © IMechE 2016.

Drill System Development for the Lunar Subsurface Exploration

NASA Astrophysics Data System (ADS)

Zacny, Kris; Davis, Kiel; Paulsen, Gale; Roberts, Dustyn; Wilson, Jack; Hernandez, Wilson

Reaching the cold traps at the lunar poles and directly sensing the subsurface regolith is a primary goal of lunar exploration, especially as a means of prospecting for future In Situ Resource Utilization efforts. As part of the development of a lunar drill capable of reaching a depth of two meters or more, Honeybee Robotics has built a laboratory drill system with a total linear stroke of 1 meter, capability to produce as much as 45 N-m of torque at a rotational speed of 200 rpm, and a capability of delivering maximum downforce of 1000 N. Since this is a test-bed, the motors were purposely chosen to be relative large to provide ample power to the drill system (the Apollo drill was a 500 Watt drill, i.e. not small in current standards). In addition, the drill is capable of using three different drilling modes: rotary, rotary percussive and percussive. The frequency of percussive impact can be varied if needed while rotational speed can be held constant. An integral part of this test bed is a vacuum chamber that is currently being constructed. The drill test-bed is used for analyzing various drilling modes and testing different drill bit and auger systems under low pressure conditions and in lunar regolith simulant. The results of the tests are used to develop final lunar drill design as well as efficient drilling protocols. The drill was also designed to accommodate a downhole neutron spectrometer for measuring the amount of hydrated material in the area surrounding the borehole, as well as downhole temperature sensors, accelerometers, and electrical properties tester. The presentation will include history of lunar drilling, challenges of drilling on the Moon, a description of the drill and chamber as well as preliminary drilling test results conducted in the ice-bound lunar regolith simulant with a variety of drill bits and augers systems.

High Temperature 300°C Directional Drilling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatterjee, Kamalesh; Aaron, Dick; Macpherson, John

2015-07-31

Many countries around the world, including the USA, have untapped geothermal energy potential. Enhanced Geothermal Systems (EGS) technology is needed to economically utilize this resource. Temperatures in some EGS reservoirs can exceed 300°C. To effectively utilize EGS resources, an array of injector and production wells must be accurately placed in the formation fracture network. This requires a high temperature directional drilling system. Most commercial services for directional drilling systems are rated for 175°C while geothermal wells require operation at much higher temperatures. Two U.S. Department of Energy (DOE) Geothermal Technologies Program (GTP) projects have been initiated to develop a 300°Cmore » capable directional drilling system, the first developing a drill bit, directional motor, and drilling fluid, and the second adding navigation and telemetry systems. This report is for the first project, “High Temperature 300°C Directional Drilling System, including drill bit, directional motor and drilling fluid, for enhanced geothermal systems,” award number DE-EE0002782. The drilling system consists of a drill bit, a directional motor, and drilling fluid. The DOE deliverables are three prototype drilling systems. We have developed three drilling motors; we have developed four roller-cone and five Kymera® bits; and finally, we have developed a 300°C stable drilling fluid, along with a lubricant additive for the metal-to-metal motor. Metal-to-metal directional motors require coatings to the rotor and stator for wear and corrosion resistance, and this coating research has been a significant part of the project. The drill bits performed well in the drill bit simulator test, and the complete drilling system has been tested drilling granite at Baker Hughes’ Experimental Test Facility in Oklahoma. The metal-to-metal motor was additionally subjected to a flow loop test in Baker Hughes’ Celle Technology Center in Germany, where it ran for more than 100 hours.« less

30 CFR 56.7003 - Drill area inspection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drill area inspection. 56.7003 Section 56.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7003 Drill area inspection. The drilling area shall be inspected for hazards before...

30 CFR 56.7012 - Tending drills in operation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tending drills in operation. 56.7012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7012 Tending drills in operation. While in operation, drills shall be...

30 CFR 57.7003 - Drill area inspection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drill area inspection. 57.7003 Section 57.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7003 Drill area inspection. The drilling area shall be...

30 CFR 57.7013 - Covering or guarding drill holes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Covering or guarding drill holes. 57.7013... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7013 Covering or guarding drill holes. Drill holes...

30 CFR 56.7052 - Drilling positions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

30 CFR 57.7003 - Drill area inspection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drill area inspection. 57.7003 Section 57.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7003 Drill area inspection. The drilling area shall be...

30 CFR 56.7012 - Tending drills in operation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tending drills in operation. 56.7012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7012 Tending drills in operation. While in operation, drills shall be...

30 CFR 56.7052 - Drilling positions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

30 CFR 57.7013 - Covering or guarding drill holes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Covering or guarding drill holes. 57.7013... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7013 Covering or guarding drill holes. Drill holes...

30 CFR 56.7012 - Tending drills in operation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tending drills in operation. 56.7012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7012 Tending drills in operation. While in operation, drills shall be...

30 CFR 56.7003 - Drill area inspection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drill area inspection. 56.7003 Section 56.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7003 Drill area inspection. The drilling area shall be inspected for hazards before...

30 CFR 56.7012 - Tending drills in operation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tending drills in operation. 56.7012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7012 Tending drills in operation. While in operation, drills shall be...

30 CFR 57.7003 - Drill area inspection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill area inspection. 57.7003 Section 57.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7003 Drill area inspection. The drilling area shall be...

30 CFR 56.7003 - Drill area inspection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill area inspection. 56.7003 Section 56.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7003 Drill area inspection. The drilling area shall be inspected for hazards before...

30 CFR 56.7052 - Drilling positions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

30 CFR 56.7052 - Drilling positions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

30 CFR 56.7003 - Drill area inspection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drill area inspection. 56.7003 Section 56.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7003 Drill area inspection. The drilling area shall be inspected for hazards before...

30 CFR 56.7052 - Drilling positions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

30 CFR 57.7003 - Drill area inspection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drill area inspection. 57.7003 Section 57.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7003 Drill area inspection. The drilling area shall be...

30 CFR 57.7013 - Covering or guarding drill holes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Covering or guarding drill holes. 57.7013... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7013 Covering or guarding drill holes. Drill holes...

30 CFR 57.7003 - Drill area inspection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drill area inspection. 57.7003 Section 57.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7003 Drill area inspection. The drilling area shall be...

30 CFR 56.7012 - Tending drills in operation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tending drills in operation. 56.7012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7012 Tending drills in operation. While in operation, drills shall be...

30 CFR 57.7013 - Covering or guarding drill holes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Covering or guarding drill holes. 57.7013... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7013 Covering or guarding drill holes. Drill holes...

30 CFR 56.7003 - Drill area inspection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drill area inspection. 56.7003 Section 56.7003... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7003 Drill area inspection. The drilling area shall be inspected for hazards before...

30 CFR 57.7013 - Covering or guarding drill holes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Covering or guarding drill holes. 57.7013... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7013 Covering or guarding drill holes. Drill holes...

30 CFR 56.7050 - Tool and drill steel racks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tool and drill steel racks. 56.7050 Section 56... Jet Piercing Drilling § 56.7050 Tool and drill steel racks. Receptacles or racks shall be provided for drill steel and tools stored or carried on drills. ...

30 CFR 56.7050 - Tool and drill steel racks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tool and drill steel racks. 56.7050 Section 56... Jet Piercing Drilling § 56.7050 Tool and drill steel racks. Receptacles or racks shall be provided for drill steel and tools stored or carried on drills. ...

30 CFR 56.7050 - Tool and drill steel racks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tool and drill steel racks. 56.7050 Section 56... Jet Piercing Drilling § 56.7050 Tool and drill steel racks. Receptacles or racks shall be provided for drill steel and tools stored or carried on drills. ...

30 CFR 56.7050 - Tool and drill steel racks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tool and drill steel racks. 56.7050 Section 56... Jet Piercing Drilling § 56.7050 Tool and drill steel racks. Receptacles or racks shall be provided for drill steel and tools stored or carried on drills. ...

Communication adapter for use with a drilling component

DOEpatents

Hall, David R [Provo, UT; Pixton, David S [Lehi, UT; Hall,; Jr,; Tracy, H [Provo, UT; Bradford, Kline [Orem, UT; Rawle, Michael [Springville, UT

2007-04-03

A communication adapter is disclosed that provides for removable attachment to a drilling component when the drilling component is not actively drilling and for communication with an integrated transmission system in the drilling component. The communication adapter comprises a data transmission coupler that facilitates communication between the drilling component and the adapter, a mechanical coupler that facilitates removable attachment of the adapter to the drilling component, and a data interface.

Environmental Measurement-While-Drilling System and Horizontal Directional Drilling Technology Demonstration, Hanford Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, C.V.; Lockwood, G.J.; Normann, R.A.

1999-06-01

The Environmental Measurement-While-Drilling (EMWD) system and Horizontal Directional Drilling (HDD) were successfully demonstrated at the Mock Tank Leak Simulation Site and the Drilling Technology Test Site, Hanford, Washington. The use of directional drilling offers an alternative to vertical drilling site characterization. Directional drilling can develop a borehole under a structure, such as a waste tank, from an angled entry and leveling off to horizontal at the desired depth. The EMWD system represents an innovative blend of new and existing technology that provides the capability of producing real-time environmental and drill bit data during drilling operations. The technology demonstration consisted ofmore » the development of one borehole under a mock waste tank at a depth of {approximately} {minus}8 m ({minus}27 ft.), following a predetermined drill path, tracking the drill path to within a radius of {approximately}1.5 m (5 ft.), and monitoring for zones of radiological activity using the EMWD system. The purpose of the second borehole was to demonstrate the capability of drilling to a depth of {approximately} {minus}21 m ({minus}70 ft.), the depth needed to obtain access under the Hanford waste tanks, and continue drilling horizontally. This report presents information on the HDD and EMWD technologies, demonstration design, results of the demonstrations, and lessons learned.« less

Biological Evaluation of Implant Drill Made from Zirconium Dioxide.

PubMed

Akiba, Yosuke; Eguchi, Kaori; Akiba, Nami; Uoshima, Katsumi

2017-04-01

Zirconia is a good candidate material in the dental field. In this study, we evaluated biological responses against a zirconia drill using a bone cavity healing model. Zirconia drills, stainless steel drills, and the drilled bone surface were observed by scanning electron microscopy (SEM), before and after cavity preparation. For the bone cavity healing model, the upper first and second molars of Wistar rats were extracted. After 4 weeks, cavities were prepared with zirconia drills on the left side. As a control, a stainless steel drill was used on the right side. At 3, 7, and 14 days after surgery, micro-CT images were taken. Samples were prepared for histological staining. SEM images revealed that zirconia drills maintained sharpness even after 30 drilling procedures. The bone surface was smoother with the zirconia drill. Micro-CT images showed faster and earlier bone healing in the zirconia drill cavity. On H-E staining, at 7 days, the zirconia drill defect had a smaller blank lacunae area. At 14 days, the zirconia drill defect was filled with newly formed bone. The zirconia drill induces less damage during cavity preparation and is advantageous for bone healing. (197 words). © 2016 The Authors Clinical Implant Dentistry and Related Research Published by Wiley Periodicals, Inc.

Changes in Stratospheric Transport and Mixing During Sudden Stratospheric Warmings

NASA Astrophysics Data System (ADS)

de la Cámara, A.; Abalos, M.; Hitchcock, P.

2018-04-01

The extreme disruptions of the wintertime stratospheric circulation during sudden stratospheric warmings (SSW) have large effects on tracer concentrations through alterations in transport. This study analyzes the changes in residual circulation and isentropic mixing associated with SSWs, by performing composites using reanalysis (European Centre for Medium-Range Weather Forecasts Re-Analysis Interim) and simulations of the Whole Atmosphere Community Climate Model. The advective Brewer-Dobson circulation accelerates around 15 days prior to the wind reversal at 60°N, 10 hPa during the onset of SSWs. Soon afterward, it decelerates, leading to reduced advective transport into the vortex and descent over the pole, which persist for more than 2 months below 30 hPa. The isentropic mixing has a distinct signature in altitude: It is enhanced at the central date of the SSW in the midstratosphere (about 10 hPa or 800 K), and this signal is delayed and more persistent at lower altitudes. It is shown that sufficiently deep SSWs (particularly those related to Polar-night Jet Oscillation events) have a stronger response in the Brewer-Dobson circulation and mixing. In particular, both the polar downwelling and the tropical upwelling are anomalously weak in the lower stratosphere for 90 days after the onset of Polar-night Jet Oscillation events. The redistribution of potential vorticity during the life cycle of SSWs is discussed due to its relevance for the stratospheric circulation. It is shown that the diffusive flux of potential vorticity, calculated in equivalent latitude coordinates, remains anomalously high in the lower stratosphere, a feature that is not seen in more conventional advective eddy fluxes across latitude circles.