bluuebunny/crossref_metadata_2025 huggingface dataset:
Weed Management in Organically Grown Kale Using Alternative Cover Cropping Systems
Authors: Mennan Husrev , Ngouajio Mathieu , Kaya Emine , Isık Dogan
Published: March 2009

Organic vegetable producers have limited options for managing weeds. They cite weed management as their number one research priority. Studies were conducted in 2004 and 2005 at the Black Sea Agricultural Research Institute, Samsun, Turkey, to determine the weed suppressive effects of summer cover crops in organic kale production. Treatments consisted of grain sorghum, sudangrass, hairy vetch, grain amaranth, pea, and fallow. Weed density and total weed dry biomass were assessed before and at 14, 28, and 56 d after incorporation (DAI) of the cover crops. Kale was transplanted 14 DAI and hand weeded once after last weed evaluation (56 DAI). All cover crops produced at least 1 ton/ha (t/ha) biomass; grain sorghum produced more dry matter than all other cover crops in both years. After incorporation of the cover crops, hairy vetch and sorghum treatments showed fewer species, lower weed density, and total weed dry biomass compared with other treatments. Cover crops suppressed emergence of common purslane, common lambsquarters, redroot pigweed, European heliotrope, field pennycress, annual sowthistle, black nightshade, shepherd's-purse, wild mustard, sun spurge, Persian speedwell, annual mercury, and jimsonweed up to 56 DAI. Total kale yield in hairy vetch treatments was more than double that of the no cover crop, and was significantly higher than yield from the other cover crop treatments. These results indicate that hairy vetch, grain sorghum, and sudangrass have ability to suppress early-season weeds in organic kale production.
Swamp Dodder (Cuscuta gronovii) Applied Ecology in Carrot Production
Authors: Konieczka Christopher M. , Colquhoun Jed B. , Rittmeyer Richard A.
Published: March 2009

Swamp dodder continues to spread through Wisconsin carrots, reducing crop yield and quality. Greenhouse research was conducted to evaluate the effect of swamp dodder infection timing on carrot development and to evaluate carrot cultivar tolerance to the parasite. Data collection included measurement of carrot processing qualities such as root length, root diameter, and fresh weight, as well as quantification of carrot leaf biomass and swamp dodder biomass. Carrot processing qualities were reduced the most in carrots infected 14 d after emergence (DAE). Carrots infected 70 DAE were similar to the noninfected carrots for all processing qualities. Carrot cultivars differed in tolerance of swamp dodder parasitism. All parameters for cultivar tolerance were significantly reduced by swamp dodder infection; however, ‘Enterprise’, ‘Sweet Bites’, ‘Sugar Snax 54’, ‘Topcut 93’, and ‘Mokum’ were most tolerant of parasitism and exhibited minimal reductions in root length, diameter, and fresh weight compared with other cultivars. ‘7626B’, ‘Bolero’, ‘Legend’, and ‘Imperial Cuts’ cultivars grew poorly when parasitized.
Tolerance of Foxtail Millet to Combinations of Bromoxynil, Clopyralid, Fluroxypyr, and MCPA
Authors: May William E. , Johnson Eric N. , Ulrich Dan J. , Holzapfel Christopher B. , Lafond Guy P.
Published: March 2009

When solid stands of foxtail millet are cut for swath grazing, the grazing season for cattle is extended and winter feeding costs reduced. The economic success of this practice depends on inexpensive weed control. Eight single- and double-rate herbicide combinations (g ai/ha) were evaluated and compared to a weed-free check: MCPA + bromoxynil (280 + 280 or 560 + 560); MCPA + clopyralid (560 + 100 or 1120 + 200); MCPA + fluroxypyr (562 + 108 or 1124 + 216); and MCPA + clopyralid + fluroxypyr (560 + 100 + 144 or 1120 + 200 + 288). This study was conducted at Indian Head, Saskatchewan (SK) in 2004, 2005, 2006, and 2007 and at Scott, SK, in 2006 and 2007. Crop injury and dry matter yield were measured. Results of the study indicate that crop injury exceeded 20% at only one out of six sites at 7 to 14 d after herbicide treatment. Double-rate MCPA + bromoxynil treatments had higher injury ratings than the weed-free check 7 to 14 d after treatment in all site years. As the growing season progressed, injury ratings tended to decline except at Scott in 2007, where injury ratings at the 21 to 35 d period were numerically greater than the other two rating periods. There were no differences among treatments for crop biomass production. We conclude that all four herbicide combinations at the labeled rate are safe to use on foxtail millet in Saskatchewan, and probably in other areas with similar environmental growing conditions.
Pheochromocytomas and extra-adrenal paragangliomas detected by screening in patients with SDHD-associated head-and-neck paragangliomas
Authors: Havekes B , van der Klaauw A A , Weiss M M , Jansen J C , van der Mey A G L , Vriends A H J T , Bonsing B A , Romijn J A , Corssmit E P M
Published: March 2009

Patients with SDHD-associated head-and-neck paragangliomas (HNP) are at risk for developing pheochromocytomas for which screening has been advised. To assess clinical, biochemical, and radiological outcomes of screening in a large single-center cohort of SDHD-positive patients with HNP and to address the necessity for repetitive follow-up, we evaluated 93 patients with SDHD-associated HNP (p.Asp92Tyr, p.Leu139Pro). Screening consisted of measurement of 24 h urinary excretion of catecholamines and/or their metabolites in duplicate, which was repeated with intervals of 2 years if initial biochemical screening was negative. In patients, in whom urinary excretion was above the reference limit, imaging studies with 123I-MIBG (metaiodobenzylguanidine) scintigraphy and magnetic resonance imaging (MRI) and/or computed tomography (CT) were performed. Pheochromocytomas and extra-adrenal paragangliomas were treated surgically after appropriate blockade. Median follow-up was 4.5 years (range 0.5–19.5 years). Twenty-eight out of the 93 patients were included in our study and underwent additional imaging for pheochromocytomas/extra-adrenal paragangliomas. In 11 out of the 28 patients intra-adrenal pheochromocytomas were found. Extra-adrenal paragangliomas were discovered in eight patients. These tumors were detected during initial screening in 63% of cases, whereas 37% were detected after repeated biochemical screening. One patient was diagnosed with a biochemically silent pheochromocytoma. The high prevalence of pheochromocytomas/extra-adrenal paragangliomas in patients with SDHD-associated HNP warrants regular screening for tumors in these patients. Paragangliomas that do not secrete catecholamines might be more prevalent than previously reported. Future studies will have to establish whether routine imaging studies should be included in the screening of SDHD mutation carriers, irrespective of biochemical screening.
On quality indicators for radar-based river flow forecasts
Authors: Collier C. G.
Published: March 2009

Although there has been considerable progress in improving the quality of radar estimates of precipitation, including developments in radar technology, the unpredictable nature of radar errors continues to discourage many operational hydrologists from using radar data quantitatively as input to models. Indeed, the tendency has been to wait for all errors to be removed. Unfortunately it is unlikely that all errors will be removed all of the time, even with new promising radar technologies such as dual polarisation systems. In this paper a procedure is proposed and partially tested for deriving a quality index from single polarisation radar based on the use of a ‘peaks-over-threshold’ (POT) parameter for gauged catchments. The procedure is tested for several different catchments and for different rainfall types. For ungauged catchments a different approach is proposed based on the fitting and analysis of an autoregressive model to rainfall time series. This procedure is tested using the radar data distributed to users in real time during major flood events in the Midlands, UK. The practicality of applying these techniques to radar data in an operational environment is discussed.
Weather radar to predict exceedances of faecal coliforms
Authors: Dale M. , Stidson R.
Published: March 2009

Weather radar data have been used in a project in Scotland to develop a methodology to improve real-time predictions of faecal coliform concentrations in bathing waters. Poor bathing water quality, characterised by high faecal coliform concentrations, is primarily caused by pollutants mobilised during wet weather in river and urban drainage catchments discharging close to beaches. This paper reports on a study carried out with data for two sites in western Scotland, Irvine and Saltcoats, where good quality radar data and a high number of water quality samples exist. The analysis shows that radar data improve on rain-gauge data in their ability to predict water quality at the beach for one site and are marginally poorer than rain-gauge data at the other site. This is an innovative use of weather radar within a system for managing water quality and points the way for similar approaches to meet the challenge of the European Union's bathing water and water framework directives.
Reduction of vitellogenin synthesis by an aryl hydrocarbon receptor agonist in the white sturgeon (Acipenser Transmontamus)
Authors: Palumbo Amanda J. , Denison Michael S. , Doroshov Serge I. , Tjeerdema Ronald S.
Published: March 2009

Migrating white sturgeon (Acipenser transmontamus) may be subject to agricultural, municipal, and industrial wastewater effluents that likely contain different classes of endocrine-disrupting contaminants. Concern is mounting about the negative effects of environmental estrogens on fish reproduction; however, in environmental mixtures, the affects from estrogenic compounds may be suppressed by aryl hydrocarbon receptor (AhR) ligands. Indeed, reductions in 17p-estradiol-induced (0.01 and 1 mg/kg) vitellogenin (VTG) levels were observed in white sturgeon coinjected with β-naphthoflavone (BNF; 50 mg/kg), a model for contaminants that activate the AhR. Variation in the time of injection was used to attempt to correlate VTG inhibition to ethoxy-resorufin-O-deethylase activity. No evidence was found to suggest that the inhibition of VTG is a direct result of enhanced estrogen metabolism by BNF-induced enzymes. Results of the present study are relevant for monitoring programs that measure VTG, because these results show that AhR-active environmental contaminants can repress VTG synthesis, which commonly is used as an indicator of estrogen-mimicking contaminants. Furthermore, suppression of natural estrogen signaling by AhR agonists may have significant effects on fish reproduction.
Beyond the Technical Limit: Turbodrilling—A Paradigm Shift to World Class Horizontal Well Construction
Authors: Mushovic Todd , Shuler David , Morlock Raymond J. , Conroy David
Published: March 2009

Drilling horizontal gas wells in a mature area of southeastern Oklahoma's Arkoma Basin recently has become operationally feasible. This was achieved as a result of a systematic approach to identifying the best combinations of technology and operating procedures to reduce flat time as a means of minimizing the well's overall cost and improving drilling efficiencies. This efficiency initiative was considered an urgent issue because the project was in its infancy, and drilling engineers needed to quickly prove feasibility. Horizontals in one Middle Atokan formation are now clearly feasible but lateral drilling in another Middle Atokan formation produced marginal results and requires additional optimization.

To achieve the efficiency goal, the Team outlined the following application objectives

➢ Reduce BHA troubles/problems and PDM failures ➢ Reduce the need to trip for bit dulls and roller cone bit drilling hour limitations ➢ Eliminate fishing for lost cones ➢ Produce a smoother wellbore ➢ Eliminate reamer trip for liner run

To meet these objectives, the Team discussed alternative drilling system approaches, and the drilling team concluded that the use of turbodrilling and impregnated bit technologies offered the most promising approach. The new higher RPM drilling system was run with outstanding results. Since the initial implementation of the impreg bit/turbodrill, the drilling team has completed the entire lateral with one bit, thereby eliminating up to six trips for replacing bits and/or tool failures. The reduction in tripping is due to using a turbine-powered drive system with substantially longer downhole life compared to a PDM and the impregnated bit's ability to finish the hole section and still have an intact cutting structure. This solved the bit trip problems resulting from the limited numbers of hours per bit and the lost cone issues with 6-1/8" TCI bits (30 hrs) and short PDC bit runs due to excessive cutter wear. Additionally, the turbine's smooth drilling action and resulting vibration reduction have significantly reduced the failure rate of expensive downhole tools. With the new turbodrill/impreg combination, 10-day runs have become the new benchmark, performance that PDMs with PDC bits could rarely achieve.
Increasing Sakhalin Extended Reach Drilling and Completion Capability
Authors: Walker Michael W. , Veselka Andrew J. , Harris Shane A.
Published: March 2009

Extended reach drilling (ERD) and completion capability at the Chayvo field, Sakhalin Island, has evolved in well design and operational practices to increase well reach to over 10.5 kilometers. This is a result of disciplined redesign based on learnings acquired throughout the program and has resulted in the successful drilling of world record measured depth ERD wells. The learnings and design changes will be discussed in this paper using a recent record well, the Chayvo Z–12, as a case study.

Implementation of the operator's drilling performance management process and integrated hole quality (IHQ) technology has enabled continuous improvement in overall rate of penetration (ROP) and hole quality. Impediments to higher ROP have been systematically engineered out of the drilling system while minimizing the level of risk. Bottomhole assembly (BHA) designs and operational practices have been modified to reduce vibration effects leading to poor borehole patterning and micro-doglegs, thus enabling a higher ROP with a better quality borehole. Detailed torque and drag modeling, engineering surveillance, and lubricants have also led to improved hole cleaning, lower equivalent circulating densities (ECD), and reduced friction effects required to drill and complete these wells.

Chayvo completion design incorporates the use of pre-drilled liners, standalone screens, swell packers, and inflow control devices (ICDs), allowing effective zonal isolation, prevention of sand production, and flow profile control. Management of ICD placement and configuration provides the flexibility for early well life zonal isolation while maintaining cost effective non-rig intervention options for the future.

The ability to effectively capture and transfer lessons learned has been a driver to the success at Chayvo. Work process and technology best practices can be rapidly integrated into operations, thereby facilitating improvement in all aspects of the drilling process.
Application of Active Heave Compensated Cranes for Mobile Offshore Drilling Units
Authors: Seierstad T. , Morawej N. , Ogg J. , Kelley M.
Published: March 2009

Active Heave Compensating (AHC) technology is not new to the industry, but it is a technology not effectively disseminated from an operation's perspective. This paper will discuss migrating well proven AHC technology from cranes on various support vessels to knuckle- boom cranes onboard mobile offshore drilling units (MODU), highlighting present load handling on these units and future applications. A new 165 ton AHC knuckle boom crane will also be examined, as it begins its lifecycle on newbuild drillships of this recent build cycle.
Control Requirements for High-End Automatic MPD Operations
Authors: Godhavn John-Morten
Published: March 2009

Automatic control solutions for drilling are expected to become widely used in the future. Both basic and more advanced control tools are well established in other communities like offshore processing facilities and oil refineries. Drilling systems, however, have traditionally been operated manually. There is a great economic potential for the introduction of automatic control providing reduced drilling time, increased regularity and improved performance, especially for wells with very narrow pressure margins. One example of automated drilling is automatic control of the downhole pressure by topside choking in managed pressure drilling (MPD) operations. Narrow drilling margins, especially in depleted reservoirs, ask for highly accurate pressure control.

StatoilHydro applied automatic MPD operations successfully offshore at the Kvitebjorn field in the North Sea in 2007, and several new MPD projects are currently being prepared. This paper presents some results from Kvitebjorn and discusses automatic control requirements for drilling operations. These requirements include a specified accuracy for a set of normal operations, such as rate changes and set point ramping during connections, surge and swab, and some failure operations, such as power loss, gas kicks and blocked choke. The paper also includes some ideas for the future of intelligent drilling operations with increasing automation.
High Angle Directional Drilling With 9 5/8-in. Casing in Offshore Qatar
Authors: Avery Michael , Stephens Tod , Al-Hadad Ali K. , Turki Mounir , Abed Malek
Published: March 2009

Programs which require drilling through unstable formations at high angle before entering the productive zone for a horizontal well are becoming more common. Casing while drilling is becoming a powerful method in mitigating both lost circulation as well as wellbore stability issues in offshore directional wells.

Occidental Petroleum of Qatar Ltd. (OPQL) is faced with this task in drilling horizontal Shuaiba wells offshore Qatar. The unstable Nahr Umr shale formation lies directly above the Shuaiba payzone and is typically drilled with 12 ¼-in. bits. The Nahr Umr shale tends to break up shortly after drilling, leading to stuck bottom hole assemblies (BHA) and difficulty running 9 5/8-in. casing. Exposure time with the Nahr Umr is often lengthened due to the requirement of continuous angle building and turning to land near horizontal.

This paper details the directional casing while drilling (DCwD) developments that have been accomplished offshore Qatar and the various advantages of the process. Due to recent advancements in tool design, it is now possible to circulate, rotate, and reciprocate the casing during BHA retrieval and setting operations, all without modifications to the rig. These advantages coupled with the versatility of rotary steerable systems allow for a much more flexible process and enables defensive measures to be taken in the event of unforeseen complications.
Breaking Records in North Kuwait Deep Gas Fields Drilling 16-in. Hole Sections at Greater Depths
Authors: Al-Saeedi Mohammed , Al-Khaldy Meshal , Mahesh V. S. , Jaffar Ali , Brown Anthony , Sharma Maneesh
Published: March 2009

Drilling the 16-in. hole section in North Kuwait deep gas fields is particularly challenging due to a lithology consisting of abrasive sandstone, shale, and limestone interbedded with hard siltstone stringers. The 16-in. section typically spuds at depths greater than 9,200 ft and consists of three main intervals. The top interval, the most demanding to drill, consists of mostly abrasive sandstone and shale; the middle consists of shale, and the bottom mostly consists of limestone and thin beds of shale.

The operator attempted to efficiently drill the 16-in. top interval using both roller cone TCI and PDC bit technology. The TCI bits had unacceptably low rates of penetration with short bit life and required multiple runs to finish the required interval. PDC bit technology delivered acceptable penetration rates but inconsistent run lengths due to impact damage from vibration likely induced by the bit, BHA, or lithology changes.

The operator determined that to efficiently drill the top interval in one run and meet performance requirements would require new bit/BHA technology. A cross-functional team was organized to aggressively seek new PDC bit technology, state-of-the-art downhole motors, and optimized drilling practices, which would be capable of consistently drilling the top interval of the 16-in. section in one run.

This paper discusses the several modeling analyses the team performed to develop the BHA/bit solution that greatly reduced lateral and torsional vibrations, in addition to the advanced bit design technology that improved bit stability. It also discusses how the collaborative effort helped the operator to break new records in drilling the most footage ever drilled in the 16-in. top interval. The application of this new technology has thus far increased the drilled footage by 35% and the average interval ROP by 42%, resulting in substantial reduction in drilling cost.
The Structure of Currents in the Deepwater Gulf of Mexico
Authors: Coholan P. D. , Feeney J. W. , Anderson S. P.
Published: March 2009

Three phenomena dominate the mesoscale ocean variability in the Gulf of Mexico. These are the Loop Current, anticyclonic (warm core) eddies, and cyclonic (cold core) eddies. When the offshore oil industry ventured out into the deepwater Gulf in the 1980s, little was known about the adverse impact these features would have on offshore operations. In the early years, it was apparent that the Loop Current regularly shed anticyclonic eddies that drifted west across the Gulf. Original analysis and models assumed that these eddies have simple elliptical shapes and that they could be sufficiently described with a few geometric parameters. Observations, however, have proven that this is not the case. Each eddy is unique, varying in shape, structure, duration, movement, and intensity. Cyclonic eddies, which were generally ignored early on, have recently been found to play a significant role in the changing dynamics of the Loop and eddies. Cyclonic/anticyclonic pairs produce some of the strongest currents observed. Oceanographers are now incorporating these features in their dynamical models to produce more accurate forecasts.

Acoustic Doppler Current Profilers (ADCPs) mounted on workboats are now commonly used for ocean current surveying to supplement existing data from drifting buoys, satellite remote sensing, and rig-mounted current meters in support of offshore construction and installation projects. Fine scale real-time monitoring of both near-surface and mid-water currents is necessary during critical phases to insure that these projects are conducted safely and efficiently. Strategically planned survey patterns are followed to best observe and forecast the encroachment of oceanographic features into areas of sensitive operations. Analysis of survey data reveals the unique properties of each feature. Not only can the data be used operationally on an hour by hour basis, but it can also be used to initialize a forecast model. Models initialized with the most recent data prove to be the most accurate and useful to offshore operators.
Evaluating the Expandability and Collapse Resistance of Expandable Tubulars
Authors: Agata J. , Tsuru E. , Sawamura M. , Asahi H. , Tsugihara H.
Published: March 2009

Expandable tubular technology is an effective method for saving on the costs of well drilling and completion. There are many applications for casing repair and slim hole casing design. The most essential performances of expandable tubular (EXP-T) are the expandability and collapse resistance, which are affected by not only the expanded pipe properties, but also the axial restraint caused by sticking pipe in well.

This paper discusses the geometrical and material factors governing pipe expandability, the effect of axial restraint during the expansion, and the collapse resistance of the expanded pipe. Two types of pipe were evaluated using pipe expander equipped with a function of the axial restraint. FEA for pipe expansion considering the pipe geometries and the mechanical property were also carried out for solving the fracture mechanism and deriving the design diagram of EXP-T. In addition, the full-scale collapse tests were performed for evaluating the collapse resistance of the expanded pipes and verifying the prediction using the conventional formulas.

These results reveal the relevant combination of the pipe geometries and the material properties for preventing the expansion failure. A potential to improve the collapse resistance of the pipe expanded under the axial restraint is drawn.
Step-Change Improvements with Wired-Pipe Telemetry
Authors: Allen Scott , McCartney Chris , Hernandez Maximo , Reeves Michael , Baksh Azaad , MacFarlane Danial
Published: March 2009

This paper describes the rationale, justification and benefits associated with the deployment of wired-pipe telemetry drillstrings at Occidental of Elk Hills, Inc. (OEHI) in Kern County, California.

Recent technological advances in Measurement While Drilling (MWD) systems, Logging While Drilling (LWD) systems, and wired-pipe telemetry systems have overcome historical data bandwidth issues enabling real-time acquisition of critical data streams. These data sets include: continuous annular pressure for equivalent circulating density (ECD) management; vibration diagnostics for drilling optimization; instantaneous downlink commands to Rotary Steerable Systems (RSS) that aide in eliminating secondary non-productive time (NPT) and enhancing directional control; and memory quality formation evaluation measurements to improve reservoir navigation and wellbore placement. With this new wealth of data, onsite drilling personnel, geoscientists, and office engineering staff are able to make real-time decisions that serve to enhance wellbore quality and reduce overall costs.

Utilizing wired-pipe to its full potential has helped to deliver an average drilling time savings of 10%.
Improvements in Efficiency for Subsea Operations in Deepwater Angola
Authors: Zook Jason , Keith Arran
Published: March 2009

Esso Exploration Angola (Block 15) Limited (EEAL) has realized substantial improvements in the efficiency of subsea operations in the deepwater environment of Angola Block 15 (AB15). EEAL dedicated a work vessel primarily to subsea activities and further improved efficiency by continuously evaluating operations for potential improvement. Given the current higher cost environment that exists throughout the industry, EEAL has increased its efforts to evaluate improving efficiencies for subsea operations, specifically during simultaneous operations (SIMOPS). Improvements in efficiency and schedule certainty were seen as a result of dedicating a work vessel primarily to subsea operations. This paper will present case histories of the various operations such as Suction Embedded Plate Anchor (SEPLA) handling, close tolerance well positioning, and horizontal christmas tree (HXT) installation, both on and off the mobile offshore drilling unit (MODU) critical path. The relative impact on efficiency and the indirect benefits of a dedicated work vessel will also be discussed.
The Successful Application of Combined New Technologies to Reach Isolated Hydrocarbon Reserves Offshore Dubai
Authors: Lagler Thomas , Alhaj Mouad Hameed , Iskander Gamal Ramses , Rhodes Jonathan Charles , Al-Kholy Wael Ahmed , Drumm Niall
Published: March 2009

Offshore Dubai is a maturing oil province and to access outlying, isolated hydrocarbon reserves it is necessary to expose several unstable sections of troublesome shale during drilling operations. Historically during the drilling of these wells, wellbore time-based instability issues have been experienced in the Aruma and Laffan shales on offset wells with shorter buildup sections. It is therefore necessary to drill these sections as efficiently as possible, minimizing the time these shales are exposed.

Dubai Petroleum looked at a combination of new technologies available in the market that could help both to optimize the drilling of these sections and to meet the directional objectives. To control the shales a high-performance water-based mud (HPWBM) system with triple inhibition was proposed to Dubai Petroleum after a series of tests and field experience in the region.

To achieve the directional objectives and minimize the time to drill the section, a performance drilling system (rotary steerable tool in combination with a modular motor) and drilling dynamics sub were suggested. The section was drilled safely in a single run with all drilling objectives achieved and breaking all previous 24-hr ROP drilling records for an offshore Dubai Petroleum well. No shale instability issues were experienced, including the longest Aruma shale section ever drilled by Dubai Petroleum.

The combination of new technologies and detailed planning applied offshore Dubai for the first time allowed a step change in the Dubai Petroleum offshore drilling and enable previously inaccessible hydrocarbon reserves to be reached and produced.
Remote Automated Directional Drilling Through Rotary Steerable Systems
Authors: Melgares Hernan , Grace Will , Gonzalez Felipe , Alric Claudio , Palacio Julio , Akinniranye Goke
Published: March 2009

Rotary Steerable Systems (RSS) are well known as drilling optimization steering tools. Better borehole quality and faster rates of penetration are achieved by RSS capability to steer the wells without sliding. The evolution of RSS has been very rapid in the past several years, with most improvements focused on tool reliability, variety of collar sizes, electronics robustness and mechanical efficiency.

This paper describes an innovative automated method for drilling directional wells remotely with RSS, which has been successfully deployed in south Mexico during 2008. The directional driller (DD) is located remotely in the operator's office with the ability to remotely control the mud pumps. If a command is required for changing the RSS program, the system remotely controls the rig pumps to execute the downlink sequence and change the downhole settings of the RSS.

The automatic generation of the mud pulses to transmit the downlink sequences also eliminates missed commands due to human error. This system allows experienced DDs to control multiple operations, either directly through remotely drilling simultaneous wells or by providing direct supervision to less experienced DDs.

The ability to have the DD work remotely with the well engineering team improves collaborative workflows to optimize drilling performance.
Offshore Managed Pressure Drilling Experiences in Asia Pacific
Authors: Nas Steve , Toralde Julmar Shaun , Wuest Chad
Published: March 2009

Managed Pressure Drilling (MPD) has been successfully used by a number of operating companies in both onshore and offshore applications in Asia Pacific. Over 100 wells have now been drilled in the region using MPD techniques. MPD has delivered significant cost savings in almost all of the applications. The high cost of offshore drilling means that offshore MPD delivers significant cost savings when non-productive times associated with fluid losses or well control events are eliminated. MPD has now been successfully used on all the types of offshore rigs from platforms, tender rigs, jack-ups, semi-submersibles as well as drillships. Both subsea and surface stacks on floaters have been used for MPD. Drilling with a so-called "closed wellbore" using MPD equipment for drilling operations has now been proven to be beneficial on all rig types and almost all well types. All drilling, logging and completion installations can be safely executed when using MPD equipment. On most installations, only minor modifications are required to enable a closed wellbore drilling system, which in turn enables More Productive Drilling.

This paper describes the experiences with MPD equipment installations on floating rigs and on fixed installations in Asia Pacific and it provides some of the lessons learned when using MPD equipment and techniques.
A Step Change in Drilling Efficiency: Quantifying the Effects of Adding an Axial Oscillation Tool Within Challenging Wellbore Environments
Authors: McCarthy J. P. , Stanes B. H. , Clark K. W. , Kollker C. R. , Leuenberger G. E. , Rebellon J. , Grabski L. E.
Published: March 2009

Motor Steerable (MS) assemblies are used globally in the majority of directional drilling applications. However, the limitations of MS systems are often highlighted as well paths become more complicated and efficient drilling performance becomes more difficult to obtain. Tools that impart cyclic, axial oscillations into the drill string have been shown to extend the operating range of MS assemblies, particularly in slide-drilling mode, including coiled tubing applications (Robertson–2004). Adding the correct Axial-oscillation Generator Tool (AGT) to a drill string can dramatically improve slide drilling (Rasheed–2001); and significantly improve work over operations with coiled tubing as well (Tongs–2007).

When evaluating the overall performance of a drilling system, it is necessary to determine the interaction between the AGT, Bottom Hole Assembly (BHA) and drill string as a whole. This paper will document the magnitude of the forces generated by the AGT and compare them to the specifications of other common drilling components. It will confirm that the correct selection and configuration of an AGT will impart benign forces into the drilling assembly, improving the effectiveness of the drilling system, and maintaining full compatibility with the entire drill string.

Historically, measuring the actual forces transmitted by the AGT has been a challenge, as most downhole measuring devices record at sample rates significantly lower than the operating frequency of the oscillation tool. These recording devices often lack the necessary number of data channels required to fully describe the downhole dynamic environment. Furthermore, variations in bit type, BHA configuration, drilling parameters and formations make evaluating results from different wells difficult.

To accurately measure downhole vibration and other drilling parameters, a Drilling Research Tool (DRT) was used. The DRT is a high-speed, sixteen-channel, downhole dynamics recorder. By ensuring identical BHA's, drilling parameters and formations, the differences in downhole activity can be attributed to the axial oscillation system.

This paper will compare a number of field runs with and without an AGT and will quantify the actual downhole accelerations caused by adding the oscillation system to the drill string. The results will show that the addition of an effective axial oscillation tool positively influences drilling performance while maintaining compatibility with all drill string components.
Simulation of Soil Carbon Dynamics under Sugarcane with the CENTURY Model
Authors: Galdos M. V. , Cerri C. C. , Cerri C. E. P. , Paustian K. , Van Antwerpen R.
Published: March 2009

Currently there is a trend for the expansion of the area cropped with sugarcane (Saccharum officinarum L.), driven by an increase in the world demand for biofuels, due to economical, environmental, and geopolitical issues. Although sugarcane is traditionally harvested by burning dried leaves and tops, the unburned, mechanized harvest has been progressively adopted. The use of process based models is useful in understanding the effects of plant litter in soil C dynamics. The objective of this work was to use the CENTURY model in evaluating the effect of sugarcane residue management in the temporal dynamics of soil C. The approach taken in this work was to parameterize the CENTURY model for the sugarcane crop, to simulate the temporal dynamics of soil C, validating the model through field experiment data, and finally to make predictions in the long term regarding soil C. The main focus of this work was the comparison of soil C stocks between the burned and unburned litter management systems, but the effect of mineral fertilizer and organic residue applications were also evaluated. The simulations were performed with data from experiments with different durations, from 1 to 60 yr, in Goiana and Timbaúba, Pernambuco, and Pradópolis, São Paulo, all in Brazil; and Mount Edgecombe, Kwazulu‐Natal, South Africa. It was possible to simulate the temporal dynamics of soil C (R2 = 0.89). The predictions made with the model revealed that there is, in the long term, a trend for higher soil C stocks with the unburned management. This increase is conditioned by factors such as climate, soil texture, time of adoption of the unburned system, and N fertilizer management.
Water and Vapor Movement with Condensation and Evaporation in a Sandy Column
Authors: Sakai Masaru , Toride Nobuo , Šimůnek Jiří
Published: March 2009

The diffusion of warm, humid air into an initially cold, dry, sandy column was analyzed to study the movement of water vapor and liquid water under nonisothermal and low water content conditions. The analysis was performed using the HYDRUS‐1D code. While the water retention curve of sand was measured experimentally, the unsaturated hydraulic conductivity function was inversely estimated from the observed water content profiles in the column. The estimated unsaturated hydraulic conductivity function displayed a shape that reflected distinct processes of capillary pore water flow and film flow at high and low water contents, respectively. Four components of the total water flux, including thermal and isothermal liquid water and water vapor fluxes, were evaluated using the calibrated soil hydraulic properties. Evaporation and condensation rates were calculated based on water mass balance. Water vapor entered the soil column at the hot surface and condensed at the cold bottom. Subsequently, liquid water moved upward and evaporated at the moisture front in the middle of the column where the relative humidity decreased below unity. Liquid water and water vapor then circulated between the bottom and the moisture front, accompanied by condensation and evaporation processes. The impact of the enhancement factor in the thermal vapor diffusion term could not be clearly identified from available experimental water content profiles. Increases in liquid water flow and the evaporation rate could be compensated for by increases in vapor flow and the condensation rate. Additional data would be needed to fully evaluate the effect of the enhancement factor.
Decomposition of Carbon‐14‐Labeled Organic Amendments and Humic Acids in a Long‐Term Field Experiment
Authors: Tatzber Michael , Stemmer Michael , Spiegel Heide , Katzlberger Christian , Zehetner Franz , Haberhauer Georg , Roth Klaus , Garcia-Garcia Elena , Gerzabek Martin H.
Published: March 2009

The stabilization of soil organic matter (SOM) is an important process in the context of global change and is strongly affected by soil use and management. We investigated the mineralization and stabilization of 14C‐labeled wheat (Triticum aestivum L.) straw and 14C‐labeled farmyard manure under different cropping systems (crop rotation, monoculture, and bare fallow) in a long‐term field experiment established in 1967. Exponential decay equations were fitted to the measured data, and coefficients of the C pools and decay constants were estimated. The different organic amendments and cropping systems resulted in considerably different distributions and half‐lives of three modeled SOM pool compartments. Significantly lower amounts of residual 14C‐labeled material were found in the bulk soils of the bare fallow systems than the farmyard‐manured crop rotation or monoculture, indicating enhanced organic matter stabilization in the latter systems. In 2004, remaining 14C‐labeled amendments (as a percentage of the original application in 1967) in bulk soils were 8.7 ± 0.3% for crop rotation, 8.6 ± 0.4% for monoculture, 7.5 ± 0.7% for bare fallow (all farmyard‐manured), and 5.0 ± 0.6% for straw‐manured bare fallow. Humic acids extracted with 1 mol L−1 NaOH responded markedly to the different cropping systems regarding both their extraction yields and the remaining 14C label. In all cropping systems, the 14C in the extracted humic acids decreased rapidly with time. Remaining 14C‐labeled organic residues in this fraction in 2004 (as a percentage of the original application in the fraction) were 0.315 ± 0.002% for crop rotation, 0.31 ± 0.02% for monoculture, and 0.16 ± 0.02% for bare fallow (all farmyard manured). Our study therefore shows that the investigated humic acids are a dynamic SOM pool cycling at decadal and subdecadal rates.
Integrating Simulated Teaching/Learning Strategies in Undergraduate Nursing Education
Authors: Sinclair Barbara , Ferguson Karen
Published: March 2009

In this article, the results of a mixed-methods study integrating the use of simulations in a nursing theory course in order to assess students' perceptions of self-efficacy for nursing practice are presented. Nursing students in an intervention group were exposed to a combination of lecture and simulation, and then asked to rate their perceptions of self-efficacy, satisfaction and effectiveness of this combined teaching and learning strategy. Based on Bandura's (1977, 1986) theory of self-efficacy, this study provides data to suggest that students' self-confidence for nursing practice may be increased through the use of simulation as a method of teaching and learning. Students also reported higher levels of satisfaction, effectiveness and consistency with their learning style when exposed to the combination of lecture and simulation than the control group, who were exposed to lecture as the only method of teaching and learning.
The Potential Role of Daucus carota Aqueous and Methanolic Extracts on Inflammation and Gastric Ulcers in Rats
Authors: Wehbe Katia , Mroueh Mohamad , Daher Costantine F
Published: March 2009

Daucus carota (DC) is among commonly used plants in folk medicine in Lebanon and the region. The present investigation was undertaken to examine the effects of the aqueous and extracts of Daucus carota umbels against acute and chronic inflammation, gastric ulcer and antibacterial activity on rats. The effects of DC aqueous extract (DCAE) on glycemia, lipemia, hepatic, renal and pancreatic function were also examined. Results on acute inflammation showed that the aqueous and methanolic extracts (DCME) produced maximum anti-inflammatory activity at doses of 400 and 140 mg/kg body weight with 90.9 and 58.6 % inhibition, respectively. In chronic inflammation, the same doses showed maximum anti-inflammatory activity with 58 and 44.1 % inhibition, respectively. DCME showed significant protection against ethanol induced gastric ulcer with a curative ratio of 46.8 and 68.7%, respectively, at a dose of 250 mg/kg body weight. None of the extracts showed significant antibacterial activity. DCAE intake (250 mg/kg body weight) for one month period did not show adverse effects on lipemia, glycemia, hepatic and liver function except for a slight decrease in HDL cholesterol (p<0.05). In conclusion, both DCAE and DCME exhibited promising anti-inflammatory and anti-ulcerogenic potentials while showing no negative influence on liver, kidney and pancreas function.
Studies on the Production of Acid Protease by Submerged Fermentation
Authors: Sinha Shishir , Sinha Shalini
Published: March 2009

Proteases are enzymes that hydrolyze peptide bonds and, therefore, lead to the disassembly of proteins. Commercially these are extremely important as more than 60% of the total enzyme market is made up of proteases, out of which 40% are acid proteases. The objective of this study was to compare the available standard strains, Rhizopus oligosporus MTCC-556, Rhizomucor miehei MTCC-546 and Aspergillus awamori MTCC-548, which were examined for the production of acid protease by submerged fermentation. Aspergillus awamori showed maximum proteolytic activity and was selected for further optimization studies. During the course of study the medium was altered. Effect of different carbon sources (lactose, sucrose, and combination of these two in same ratios and glucose) on the proteolytic activity of acid protease produced by A. awamori MTCC 548 was studied and it was found that glucose showed highest proteolytic activity. The effect of various concentrations of glucose was also studied on the acid protease production and its 1% concentration was found to be optimum; it showed proteolytic activity of 0.11 U/ml. Among the different nitrogen sources, such as casein, peptone, skim-milk powder and peanut meal, the peanut meal was found better for enzyme production. Peanut meal, with a concentration of .2% in the medium, increased proteolytic activity up to 0.218 U/ml. The effect of additives, such as Tween-80 and chemicals like CaCl2 and skim-milk powder, was also studied and it was found that 0.05% Tween-80 was effective in enzyme production and a proteolytic activity of 0.225 U/ml was obtained. The enzyme extract was separated in the form of supernatant by using centrifuge and the enzyme activity was analyzed by Ansons method using a spectrophotometer. The enzyme produced was recovered by using a saturated solution of 80% ammonium sulphate and protein content was determined by Lowery method using a spectrophotometer. It was found that the specific enzyme activity was increased from 0.155 U/mg proteins to 0.174 U/mg proteins showing a purification fold by a factor of 1.12 by using 80% saturated ammonium sulphate.
Anti‐Poverty Politics in Chile: A Preliminary Assessment of the Chile Solidario Program
Authors: Borzutzky Silvia
Published: March 2009

This paper addresses what is one of the thorniest issues in Chile's economic policy making today: the question of poverty and the Chile Solidario program which was designed to combat extreme poverty. The paper discusses who is poor in Chile, the problems with the existing data on poverty and extreme poverty, and the content of the program. The paper also contains an assessment of the short term effects of Chile Solidario. Based on the existing data, the conclusion is that Chile Solidario has failed to reduce poverty in the short term.
Book Review of Shapiro's Is the Welfare State Justified?
Authors: Hyde Mark , Dixon John
Published: March 2009

Mark Hyde and John Dixon review Shapiro's (2007) Is the Welfare State Justified?, assessing its merits as well as its flaws.
FoxO1 Haploinsufficiency Protects Against High-Fat Diet–Induced Insulin Resistance With Enhanced Peroxisome Proliferator–Activated Receptor γ Activation in Adipose Tissue
Authors: Kim Jane J. , Li Pingping , Huntley Jessica , Chang Jeffrey P. , Arden Karen C. , Olefsky Jerrold M.
Published: March 2009

OBJECTIVE

Forkhead box O (FoxO) transcription factors represent evolutionarily conserved targets of insulin signaling, regulating metabolism and cellular differentiation in response to changes in nutrient availability. Although the FoxO1 isoform is known to play a key role in adipogenesis, its physiological role in differentiated adipose tissue remains unclear.

RESEARCH DESIGN AND METHODS

In this study, we analyzed the phenotype of FoxO1 haploinsufficient mice to investigate the role of FoxO1 in high-fat diet–induced obesity and adipose tissue metabolism.

RESULTS

We showed that reduced FoxO1 expression protects mice against obesity-related insulin resistance with marked improvement not only in hepatic insulin sensitivity but also in skeletal muscle insulin action. FoxO1 haploinsufficiency also resulted in increased peroxisome proliferator–activated receptor (PPAR)γ gene expression in adipose tissue, with enhanced expression of PPARγ target genes known to influence metabolism. Moreover, treatment of mice with the PPARγ agonist rosiglitazone caused a greater improvement in in vivo insulin sensitivity in FoxO1 haploinsufficient animals, including reductions in circulating proinflammatory cytokines.

CONCLUSIONS

These findings indicate that FoxO1 proteins negatively regulate insulin action and that their effect may be explained, at least in part, by inhibition of PPARγ function.