bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-Oscillation Pulsed Percussive Rotary Tool Enhances Drilling Through Hard Igneous Formations
Authors: Cheng Rongchao , Ge Yunhua , Wang Haige , Ni Hongjian , Zhang Hongjun , Sun Qingren
Published: July 2012

As hydrocarbon development goes deeper and more complex in Songliao Basin, drilling engineering has been put at the forefront of cost reduction and efficiency enhancement. The unique challenges resulted from high abrasiveness in hard igneous formations have triggered years of efforts for cost-effective percussive rotary drilling technology. This paper will highlight the development and application of a self-oscillation pulsed percussive tool, with in-depth analysis of its active mechanism and numerical modeling results of pressure and velocity distribution inside the self-oscillation chamber.

A two-stage oscillator designed on acoustic philosophy is introduced in the tool to create hydraulic pulse after resonance, feedback, frequency selection and amplification of high speed flow downhole. The pulse immediately induces the periodic impact against bit with high frequency and low amplitude using an appropriate hydraulic energy transfer structure. The pulsed jet, mechanical percussion and rotation are integrated to enhance breaking of hard rocks. The vibration frequency, peak value and amplitude can be adjusted with respect to oscillator geometry, size of drive spindle, and the distance between oscillator outlet and spindle top.

The elimination of moving part like conventional percussion hammer significantly simplifies tool structure, allowing better assurance of security and reliability in harsh environment. Primary test in South Songliao and extended application in Sichuan and Tarim Basin demonstrate that the tool can deliver improved ROP by 20%-36% compared with offset wells, prolonged percussion durability of more than 150 hours, enhanced deviation control capability, favorable erosion resistance and HT resistance rated to 200. Meanwhile, the pulsed jet through bit nozzles helps to improve hole cleaning and decrease rock's fracture strength.

The tool and related operational procedure provides a new enabler to conquer drilling challenges in igneous rocks, as well as in tight shale, sandstone and huge-layer of gravel encountered in China.
LWD Azimuthal Laterolog Resistivity Logging in Unconventional Reservoirs
Authors: Sinclair Paul , Anzong Li , Otteman Aaron , Wennekamp Alisha
Published: July 2012

The development of unconventional oil and gas resources is critically dependent on accurate geosteering of horizontal wells. A new type of LWD Azimuthal Laterolog Resistivity logging tool has been introduced that is specifically designed for geosteering and formation evaluation in complex carbonates, shale-gas, shale-oil, and coal-bed methane formations.

The new tool is able to detect approach to a distant parallel bed-boundary of contrasting resistivity that is either higher or lower than the borehole environment. This enables predictive geosteering if the tool is not installed too far from the drill-bit. Conventional wave-propagation tools respond mainly to nearby conductive anomalies, which can limit their application in geosteering shale-oil wells where the target formation is often lower resistivity than those on upper or lower boundaries, or when the borehole traverses a fault and the target formation is higher resistivity and located in an unknown direction.

Laterolog types of tools are capable of accurate measurement over a wide range of resistivity from 0.2 – 20,000 ohm.meters, enabling hydrocarbon saturation calculation even in tight carbonate formations. Many carbonate formations, and most coal seams, produce from natural fractures or vugs. The new tool has thin-bed resolution of 0.14 meters, enabling it to image the more productive zones for real-time production analysis while drilling, with significant potential cost-savings.

The GRT tool has been commercial for two years, accumulating several thousands of hours of drilling time in operations provided by several independent MWD service companies. Successful geosteering jobs have been completed in the Montney, Bakken, Viking (Canada), Niobrara, and Avalon (USA) unconventional formations. The first test in China was in Talimu Oilfield, where the new tool was able to reproduce logs from a wireline Dual Laterolog in resistivities ranging from 20,000 – 100,000 ohm.meters. Tests have also been run in Tuha and Changqing (Sulige) oil and gas fields.

A description of the tool operating theory, design objectives, unique real-time geosteering display, and logging software is presented. Some results from three years of operations in North America and China will be discussed along with logs and brief case studies.
Double Shoulder Connection Technology Enables Exploration and Production of Ultra-Deep Prospects – Case Histories and Lessons Learned in Xinjiang, China
Authors: Zhao Jingmin , Ma Linhu , Plessis Guillaume , Zha Yongjin , Lu Qiang , Su Jianwen , Liu Peng
Published: July 2012

China oil and gas operators are more and more engaged in the exploration and production of much deeper oil and gas prospects that are pushing the boundaries and limits of the traditional drill stem. A high number of ultra-deep wells (above 7 000 meters) are being drilled in the Xinjiang area. In this part of China, there is a need to improve the hydraulic and mechanical performances of the drilling tubulars used in both large and slim hole size intervals.

A key feature in these products’ performances is the rotary shouldered connection (RSC). API RSC typically requires larger profiled tool joints to provide acceptable torque and tension capacity. However, this increase s pressure losses and restricts fishability. Double shoulder connection (DSC) technology has been successfully used to address this mutually exclusive need for both torque and hydraulics.

CNPC has greatly benefited from their decision to use a first generation double shoulder connection (1st gen DSC) on various sizes of drilling tubulars to successfully drill the deepest exploration well in the Jungar basin as well as numerous exploration and production wells in the Tarim basin.

This paper will first describe the DSC technology, how it contributes to the improved drilling performance, and will present supportive case histories. The 1st gen DSC performed very successfully. Looking ahead, deeper prospects are on the horizon and further enhancements in drill pipe and DSC technology will be necessary. Prospective future options will also be discussed in this paper.
Peninsular Malaysia Coiled-Tubing Drilling Case Study: Atypical Approach to an Unconventional Drilling Technique
Authors: Abdul Rahman A. A. , Hamzah N. E. , Razak M. S. , Ahmad Fauzi N. , Jenie J. R. , Hariry H. E. , Chaari Y.
Published: July 2012

Peninsular Malaysia has a number of fields where reserves are not economical to be further exploited using conventional drilling methods. With the increase in oil prices over the last few decades, an operator decided to embark on a new drilling technique of using acoiled-tubing drilling (CTD) unit to successfully access a bypassed reservoir.

One of the candidates chosen for the project was Well D in which the completion includes 3½-in. tubing in 7-in. production casing. The challenge in this well was to place the whipstock through the cased tubing before drilling operations could be performed because there was no through-tubing (3½-in.) whipstock design for 7-in. casing available on the market. The placement of the whipstock was crucial due to the existence of a shale zone uphole through which it was to be drilled thatwould createa borehole stability issue. The other reasons taken into considerations were to avoid dual-casing exit and the potential associated complications as well as to provide a uniform wellbore to create adequate annular velocity for cuttings transportation to the surface. The team proposed an atypical solution to assist whipstock setting by plugging the entire 7-in. production casing column until the end of tubingwith cement.Once the cement was hardened and tested, a directional drilling assembly with a 2.8-in. speed mill was used to mill a pilot hole through the cement plug, boring along the high side of the casing. Next, a caliper log was run on slickline to confirm hole diameter, and a whipstock wasthen runinto the pilot hole and set with it facing toward the casing. These operations were successfully performed by a rig-less CTD package.The milling assembly was run smoothly and the sidetrack window was effectively cut prior to drilling the target sand.

The successful case study presented summarizes in detail the technique used to mill such a wellbore, the challenges presented, and considerations madein designing the job, which proved to becorrect and accurate on the first attempt.
The Influence of Wellbore Stability on the Feasibility of Extended Reach Drilling Wells: A Case Study from Offshore Vietnam
Authors: Gui Feng , Khaksar Abbas , Gilmore Todd
Published: July 2012

Wellbore stability is important for successful horizontal and extended reach drilling (ERD) wells. Hole instability problems associated with ERD wells can sometimes change the original development plan because of complications and unforeseen operational and geomechanical issues.

This paper presents a case study from offshore Vietnam, where historically, no significant wellbore stability problems had been reported for vertical and low-angled wells. There were plans to develop the field by drilling highly deviated and ERD wells from one platform. However, instability problems and significant non-productive time from frequent pack-offs, tight holes and stuck liners were encountered while drilling one of the designed wells. The hole was sidetracked three times and finally drilled at a lower angle than originally planned.

Geomechanical analysis using core, well log, drilling data and experiences were used to build a field scale geomechanical model characterizing the in situ stress, pore pressure and rock mechanical properties in both the overburden and reservoir sections. Stress-induced borehole failure observed in image logs from an offset well and diagnostic analysis of failure mechanisms from cavings recovered from the problematic well provided significant insights into the likely nature of instability problems in the ERD well. Hole instability problems were attributed to the failure of weak bedding planes and anisotropic rock strength in the shales interbedded with sandstones. To control the weak bedding and anisotropic failure, stronger mud weights were needed than were in the original plan. The required mud weight for maintaining stability varies depending on wellbore trajectory and bedding characteristics. The usagee of high mud weights is unfavorable because of possible formation damage that could occur and the risk of fracturing the reservoir (because of lower fracture gradient). Consequently, the original ERD plan had to be revised and new optimum well trajectories designed that took into account any drilling issues, in addition to completion and productivity requirements.
The First Real Time Reservoir Characterization, Well Placement and RSS Applications in Shale Gas Horizontal Well Play in Central China - A Case Study
Authors: Xing Liang , Sheng Lou ji , Qiang Zhang Yong , Hui Zhang Jie , Lei Zhang , Ju Song , Parlindungan M. H. , Habib Rana Khalid , Yu Dai Guo , Bisain Amarjit Singh
Published: July 2012

A shale gas play operator in Central China has commenced horizontal well drilling development. Upon completion of multiple vertical pilot or evaluation wells, the shale gas target reservoir zones have been identified and are to be developed with horizontal wells. Due to the difficulties and risks associated with acquiring wireline measurements in horizontal sections, Logging While Drilling (LWD) measurements along with Rotary Steerable Drilling Systems (RSS) are used to provide real time formation evaluation, allow the well to be placed optimally within the target reservoir, reduce drilling risks, improve rate of penetration and help optimize completion design.

An integrated LWD tool and RSS was run for the first time in a horizontal shale gas well. The LWD tool delivers elemental spectroscopy, formation sigma and sourceless neutron along with the conventional triple-combo measurements of gamma ray, density, thermal neutron and resistivity. The system provided:

Improved lithology determination and enhanced formation grain density evaluation from elemental capture spectroscopy. This led to improved porosity determination and completion design Optimized lateral placement in the best quality sub-layer with near-bit GR and density images The ability to avoid drilling hazards through real-time monitoring of the drilling parameters available from the LWD tool Greatly improved ROP through the improved drilling capabilities of the RSS. This minimized the time that the formation was exposed to drilling fluids before measurements were acquired. These measurements provided the information required for the success of the first horizontal drilling in a shale gas play.

This paper will detail the use of LWD measurements and a RSS drilling system for an integrated shale gas solution providing comprehensive petrophysical evaluation, accurate well placement, and drilling efficiency optimization for the first horizontal well drilled in a shale gas play in Central China.
Integrated Drilling and Evaluation Solution to Improve Malaysia Deepwater Exploration Drilling Efficiency and to Mitigate Potential Drilling Hazard
Authors: Hamzah Rosli , M’Bareck Khalil Mohamed , Wei Kitty Chan , Sisson Keith , Ming Lim Kien , Loong Ng Kwai
Published: July 2012

PETRONAS Carigali, as one of the major deepwater operators in Malaysia worked closely with the service providers to develop a series of procedures that ensures the success of two planned wells in the perspective of improving drilling efficiency and minimizing potential drilling hazard. These procedures included employing advanced technology in bottom hole assembly (BHA) design for drilling systems as well as the acquisition and monitoring of both real-time formation logging information and downhole drilling dynamics measurements.

This paper starts with sharing the result of drilling efficiency improvement comparing Jet-In and Drill-Ahead BHA using Mud Motor versus Rotary Steerable System (RSS). Secondly, we demonstrate the applications of downhole multiple-sensor- dynamics measurements which enable drilling optimization in real-time. Lastly, the utilization of formation pressure measurement while drilling to monitor and optimize the mud weight system in real-time for drilling efficiency enhancement as well as potential drilling hazard mitigation.

The RSS Jet-In and Drill-Ahead BHA achieved 83% improvement in Rate Of Penetration compared to the Mud Motor BHA. It also improved the well vertically from +/‒3° to less than 1°. The downhole drilling dynamics tool helped the driller to optimize the drilling process especially in the harsh drilling interval and confirmed the premature failure of the Hole Enlargement Device. The real-time data acquired from the formation pressure measurement sub helped the drilling team to make prompt decision on the mud program. The mud weight was reduced from 9.6 lb/gal to 9.2 lb/gal, which avoided fracturing the formation and reduced the operational cost.
Managing Shallow Gas Drilling Risk with Casing Drilling Technology in Brown Field Re-Development Campaigns
Authors: Costeno Hugo , Roed Haakon , Erivwo Ochuko , Usun Ngau Christie , Harris Andrew
Published: July 2012

Casing Drilling was introduced to optimize the drilling of the top hole section in the Phase 1 wells of the mature Samarang Field re-development campaign. Lost circulation and stuck casing incidents in the surface section had been observed in previous campaigns, and Casing Drilling was identified as a solution to mitigate these problems.

Company procedures require that a pilot hole be drilled on the first hole section out of the conductor on the first well drilled during a platform revisit, for shallow gas mitigation. Although the risk of shallow gas was considered low in the Samarang field, the requirement applied to the first well to be drilled in the campaign. In the absence of a conclusive shallow seismic survey, other analyses to evaluate the likelihood of shallow gas were used, and Casing Drilling provided a different approach to mitigating the risk of shallow gas blowout.

This paper discusses the benefits of Casing Drilling in Samarang, with special focus on its application as mitigation for a reduced risk of shallow gas blowout. It reviews the modeling and risk analysis conducted to justify and obtain the waiver required to drill without drilling the conventional pilot hole. It also discusses the lessons learned from the execution.

The implementation of Casing Drilling in mitigating the shallow gas drilling risk, among other benefits, was a significant milestone in the project. The drilling operations became more efficient based on the substitution of the pilot hole on the first well of the re-development campaign. This has opened the opportunity for potentially valuable savings in the next phase of the project (with seven platform revisits) and other similar brown fields revisit campaigns.
Mechanism and Characteristics of Horizontal Wellbore Cleanout by Rotating Jets
Authors: Song Xianzhi , Li Gensheng , Huang Zhongwei , Zhang Laibin , Tian Shouceng , Cui Liu
Published: July 2012

Horizontal wellbore cleanout by rotating jets has been developed rapidly in the past decade. However there are few investigations on mechanism and characteristics of the high pressure water jet impacting and annular helical flow, which are two primary powers to break up the consolidated bed, lift and suspend particles, and increase the wellbore cleanout efficiency. To realize the characteristic of helical flow, the pathilines of rotating high pressure jets and annular velocity distributions were investigated firstly in this paper. The results indicated that the motive power to form the annular helical flow is the non-uniform cross flow generated by partial lateral jets which impact on the wall at an angle, while other jets provide the fluid sources. Further, base on the particle trajectory model and liquid-solid mixture model, the motions of particle, the annular distribution of sand velocity and concentration in annular helical flow were carried out. The pathlines of sand were spiral curves around the drill pipe in the annular helical flow, which can enhance the sand moving ability and increase the horizontal wellbore cleanout efficiency finally. The influences of flow rate, particle size, nozzle assemblies on the annular helical flow strength and sand transportation efficiency were analyzed comprehensively. Finally, the downhole tool was designed according the theoretical results and has been tested in hundreds wells in China. The test showed that it can greatly improve the oil and gas well production and reduce the operating duration. This paper is beneficial to investigate characteristic of sand sweeping by annular helical flow and optimize the tool structure, operation parameters.
Optimization of Casing Drilling Performance Using PAYZONE Simulator and Historical Well Data
Authors: Mahmoud R. , Kelessidis V. C. , Karimi M. , Sankar V.
Published: July 2012

Assessment of drilling performance during Casing Drilling and optimization of the process has been achieved using an existing computer simulator, which has not been tested before in Casing Drilling applications while its value has been proven in conventional drilling. The simulator allows prediction of ROP using standard drilling data of WOB, RPM, flow rate, and formation parameters. Use of simulator post drilling allows fine tuning it to match drilling performance so that future jobs in the same field could be more optimally designed.

Different lithologies along the wellbore were defined in terms the rock type, strength, and abrasivity from drilling data collected while Casing Drilling of a 2000 ft well in Haynesville shale, where ROP was high in the upper part but fairly low in the lower part. Rock strength data normally is not given and estimation was made from databases for similar rocks while they could be estimated from sonic data if available.

Running the simulator allows for re-drilling the well utilizing all basic data and trying to match the real drilling time curve and the measured ROP. Good matching was achieved for the drilling depth-time and also ROP values were matched well over the whole depth interval. Using the simulated model, WOB and RPM were optimized to increase the ROP at the lower part of the well. The results proved that the simulator can simulate Casing Drilling effectively as it has proved its value for conventional drilling.

This work shows that the simulator can help the driller to use historical data of Casing Drilling and then by applying different scenarios, e.g. increasing WOB or RPM and he can apply them while drilling a new well to obtain higher ROP. Using the simulation results, optimal drilling parameters can thus be found for drilling future wells in similar geologic environments.
New Technique: Hydra-jet Fracturing for Effectiveness of Multi-zone Acid Fracturing on an Ultra Deep Horizontal Well and Case Study
Authors: Li G. , Sheng M. , Tian S. , Huang Z. , Li Y. , Yuan X.
Published: July 2012

The placement of multiple fractures in deep horizontal wells is more difficult than that in shallow formations due to HTHP conditions. This paper presents the latest advances in hydra-jet acid fracturing for solving problems in the process of deep well acid fracturing. Basic researches and application evaluations were conducted to overcome down-hole conditions. Special schedule was designed delicately to lower the cracking pressure. The jet velocity was increased more than 800ft/sec to enhance the penetration efficiency. Acid pad fluid also was jetted to the target point for 15 minutes to erode carbonate rock, which leads to lower the rock strength. An explanation how to execute process has been included in details. The different procedures of treatment in shallow and deep reservoir were also discussed.

A novel hydra-jet acid fracturing job was performed with great success on two horizontal wells in an ultra deep carbonate reservoir in China. Seven separated acid fractures were placed along horizontal section from 19,816.3∼21,056.4ft in one well and a large total acid volume of 21,824.5ft3. After acid fracturing, the well produced naturally high rate of 251∼314STB/D. The other well is completed with un-cemented liners and the deepest treatment was applied at the TVD of 20,999.1ft. Four separated fractures were achieved along the 656.17ft lateral section. The pump pressure was controlled in the scope of predicted value (Below 10,000psi).

The main finding is that the hydra-jet acid fracturing has two mechanisms. The first is the hydraulic dynamic sealing effect and the second is the reduction of the time of acid-rock reaction to extend the effective distance. An addition, hydra-jet acid fracturing method proved the effectiveness of delivering acid fractures in the ultra deep horizontal wells.
The Research of Seabed Rescue Equipment and Method of Uncontrolled Blowout in Offshore Drilling
Authors: Ren Meipeng , Li Xiangfang , Shi Fuquan , Ma Long , Xu Darong
Published: July 2012

Presently, rescue equipment and method for uncontrolled blowout in offshore drilling are very rare, of which the consequences were very serious. With analysis of mechanics of materials based on shut-in water hammer pressure and wellhead pressure while rescuing, and fluid mechanics of uncontrolled blowout based CFD, a rescue equipment for uncontrolled blowout in offshore drilling has been invented, and proposing a rescue method. There are several emergency scenario have been made. Take the "deep horizon oil rig" in the gulf of Mexico for example, the flow field properties around this equipment could be calculated by software to prove the reliability of it. The equipment is a conceptual invention which could be designed in different types according to the size and strength of original wellhead. This equipment has a function of rescuing and oil collecting, it could prevent well blowout and collect leaped oil as well.
Enhance Service Capacity and Boost Development Return
Authors: Li Guoshun , Wang Peng , Li Ji , Jia Pingjun , Liu Meiquan
Published: July 2012

In order to meet the demand for energy in economic development, CNPC has initiated the "three-enhancement" project (enhancing speed, enhancing efficiency, enhancing qualification,) to enhance drilling capacity. In recent 3 years, the cycle for well construction in major drilling speed enhancement blocks has been shortened by more than 50%. The single well yield enhancement project has been carried out with large- scale application of horizontal well, underbalanced drilling and staged fracturing technologies, so that the numbers of annually drilled horizontal wells and staged fractured wells have exceeded 1000 and 500 respectively, and number of underbalanced wells reaches 350. The yield of horizontal wells is 3 times of vertical wells, realizing efficient development of low quality reservoir.

The paper presents our thought for drilling speed enhancement, including the integrated application of mature technologies and such critical equipment as vertical drilling, fine-managed pressure drilling (FMPD) and geosteering tools developed for overcoming bottleneck difficulties. The paper also introduces our experiences in terms of development of tight gas, shale gas, CBM etc and other oil and gas reservoirs with integrated application of horizontal well, underbalanced drilling and staged fracturing technologies.
Building local/lay flood knowledges into community flood resilience planning after the July 2007 floods, Gloucestershire, UK
Authors: McEwen Lindsey , Jones Owain
Published: July 2012

A UK Cabinet Office review after the 2007 floods highlighted different types of knowledge needed for effective flood risk management, along with knowledge gaps. This paper explores key, emerging aspects of this expanded knowledge base, namely relationships between expert and local/lay knowledges, the changing nature of local knowledge of community flood risk, and how attempts are being made to incorporate local knowledge into science, policy and practice. Sustainable flood knowledge, as an aspiration, integrates expert, local and political knowledge to build community flood resilience. The research involved stakeholder interviews undertaken before and after the 2007 floods, Severn catchment, UK and examination of policy documentation. The paper focuses on scale issues in relation to knowledge types suggesting that local knowledge can be ‘expert’ in large-scale mapping of flood processes. It reflects on how local flood knowledges can be captured, shared, harnessed and used, and assimilated into governance structures for flood resilience planning. The paper recognises progress in integrating local knowledges in flood science and governance, but also highlights challenges. It concludes that the 2007 UK flood experience is generating new understandings of the value of local knowledges, and how these might be successfully used in flood risk management practice.
Prediction intervals for rainfall–runoff models: raw error method and split-sample validation
Authors: Ewen John , O'Donnell Greg
Published: July 2012

A method (the ghost method) is developed here that calculates prediction intervals for the discharge hydrograph for a river catchment. It uses a calibrated rainfall–runoff model and a dataset containing raw errors such as residuals between observation and simulation. When calculating prediction intervals, raw errors are selected from the dataset and applied to the simulated hydrograph. The selection method is based on matching the simulated hydrological conditions to the hydrological conditions associated with the raw errors. To test the method, the split-sample calibration-validation approach advocated by Klemeš and used widely in hydrology is extended so that the data available for calibrating and testing are divided into three parts rather than two, called periods A, B and C. The rainfall–runoff model is calibrated for period A. For period B, the method by which prediction intervals are calculated is calibrated to give a specified high level of containment (e.g. 99% of observations lie within the prediction interval). Period C is used for testing, carried out in a way that shows the performance expected under operational conditions for real-world problems. Prediction intervals are calculated for the Hodder catchment, northwest England.
Modelling and reconstruction of the River Kennet palaeohydrology and hydrogeology: Silbury Hill and Avebury in 4,400 BP
Authors: Whitehead P. G. , Edmunds W. M.
Published: July 2012

With the availability of Global Circulation Models (GCMs) it is now possible to apply hydrological and hydrogeological models and knowledge to assess environmental conditions in past climates. In the upper Kennet there is considerable interest in the development of the construction of the man-made hill at Silbury. Silbury was built in several stages over a period of time and the question arises as to the availability of water for the people who built Silbury. The current Kennet flows at Silbury are low and the current stream tends to be dry for on average 5 months of the year. The aim of the research has been to assess the palaeohydrology of the Silbury Hill and Avebury area and determine the flow rates, groundwater levels and hydrological conditions in 4,400 BP. This has been undertaken using hydrogeological mapping and modelling techniques, making use of outputs from a GCM to recreate past flows and groundwater levels in the upper Kennet at Avebury and Silbury. The modelling results indicate a past wetter climate in the area, with higher river flows and higher groundwater levels, which would have sustained the local populations through dryer summer months.
Development and validation of a motivational persistence scale
Authors: Constantin Ticu , Holman Andrei , Hojbotă Maria
Published: July 2012

The main goal of our research was to develop a new measure of persistence and
to assess its construct validity and psychometric proprieties. First, we
discuss the history of the psychological construct of persistence, defined
here as the tendency to remain engaged in specific goal-related activities,
despite difficulties, obstacles, fatigue, prolonged frustration or low
perceived feasibility. The developed scale, measuring motivational
persistence, contains three-factors: long-term purposes pursuing, current
purposes pursuing and recurrence of unattained purposes. The results of the
two validation studies conducted, employing both exploratory and confirmatory
factor analysis, advocate the hypothesized structure. Also, the Pearson and
canonical correlations between the three factors of the new self-report scale
and other three related measures (and their factors) indicate good levels of
convergent and divergent validity of the new scale.
Oribatid mites (Acari, Oribatida) of bushy patches in steppe vegetation of cape Tarkhankut in Crimea (Ukraine)
Authors: Seniczak Stanisław , Kaczmarek Sławomir , Seniczak Anna
Published: July 2012

Oribatid mites (Acari, Oribatida) of bushy patches in steppe vegetation of cape Tarkhankut in Crimea (Ukraine)

The density, species number, and age structure of oribatid mites were investigated in bushy patches (elm, hawthorn, hawthorn with rose) in steppe vegetation of cape Tarkhankut (Crimea). In these patches, the density of mites in shrub litter, herbs and moss was higher, but species number was similar like in open steppe vegetation. Hawthorn increased the density distinctly more than hawthorn with rose or bushy elms. In bushy patches, the samples of moss were richer in mites than samples of shrub litter alone or with herbs. Among oribatid mites, Chamobates c.f. spinosus and Trhypochthonius tectorum were most abundant, but relatively abundant and common were also Tectocepheus velatus, Oribatula sp. 1, Achipteria nitens, and Brachychthonius berlesei. In oribatid mite communities, adults dominated, but the age structure of populations greatly depended on vegetation type.
Arthropods in the nests of the Common Kestrel (Falco tinnunculus)
Authors: Kaľavský Martin , Fenďa Peter , Holecová Milada
Published: July 2012

Arthropods in the nests of the Common Kestrel (Falco tinnunculus)

In 2008 we analyzed nest material from 25 nests of the Common Kestrel nesting in the residential and rural areas of Bratislava. 4486 arthropod individuals were determined, belonging to the orders Coleoptera, Mesostigmata, Prostigmata, Astigmata, Oribatida, Diptera and Siphonaptera. The arthropod fauna in the nests of the Common Kestrel can be classified into 4 groups: mites, dipteran larvae, adult beetles and dipterans. Three families of avian ectoparasites were present, comprising 26% of the total arthropod abundance. The remaining 74% of arthropod abundance in the nests comprised coprophagous and nidicolous species.
Between Tribalism and Trust: The IPCC Under the "Public Microscope"
Authors: Beck Silke
Published: July 2012

This article explores how the Intergovernmental Panel on Climate Change (IPCC) has dealt with growing public scrutiny of its workings. It reviews recent initiatives set up to respond to the Climategate controversy. An independent review of the IPCC undertaken by an international scientific umbrella body—InterAcademy Council—can be shown to have triggered one of the turning points in the debate, placing the focus of attention on the IPCC's transparency and accountability. However, the council's recommendations have been implemented by the IPCC in such a way that the issue of public trust is treated as one of effective communication. The article then explains how IPCC's responses to Climategate can be traced back to the linear model of expertise. The article concludes with a discussion why the challenge of producing policy-relevant knowledge under conditions of heightened public scrutiny also requires new forms of scientific appraisal aimed at wider publics.
Bythocythere solisdeus n. sp. and Cytheropteron eleonorae n. sp. (Crustacea, Ostracoda) from the Early Pleistocene Bathyal Sediments of Cape Milazzo (NE, Sicily)
Authors: Sciuto Francesco
Published: July 2012

Two new fossil species of Ostracoda belonging to the genus Bythocythere Sars, 1866, Bythocythere solisdeus n. sp. and to the genus Cytheropteron Sars, 1866, Cytheropteron eleonorae n. sp. are described. The specimens come from the upper silty sand layers of the Globorotalia truncatulinoides excelsa Zone (“Sicilian” stage), cropping out in “Cala S. Antonino” along the western side of the Cape Milazzo Peninsula (NE Sicily). Both species belong to a typical Bathyal ostracod association characterized by very low temperatures.
Cytotoxic Effect of Eudesmanolides Isolated from Flowers of Tanacetum vulgare ssp. siculum
Authors: Rosselli Sergio , Bruno Maurizio , Raimondo Francesco Maria , Spadaro Vivienne , Varol Mehmet , Koparal Ayşe Tansu , Maggio Antonella
Published: July 2012

A phytochemical analysis of the dichloromethane extract from the flowers of a subspecies of Tanacetum vulgare growing in Sicily was carried out. Five known sesquiterpene lactones with the eudesmane skeleton have been isolated and the cytotoxic activity of these compounds was tested in vitro on A549 (human lung carcinoma epithelial-like) and V79379A (Chinese hamster lung fibroblast-like) cells using the tetrazolium salt reduction (MTT) assay. All of tested compounds induced high time- and concentration-dependent cytotoxic effects.
Effect of Plasma Treatment on Multi-Walled Carbon Nanotubes for the Detection of H2S and SO2
Authors: Zhang Xiaoxing , Yang Bing , Wang Xiaojing , Luo Chenchen
Published: July 2012

H2S and SO2 are important characteristic gases of partial discharge (PD) generated by latent insulated defects in gas insulated switchgear (GIS). The detection of H2S and SO2 is of great significance in the diagnosis and assessment of the operating status of GIS. In this paper, we perform experiments on the gas sensitivity of unmodified multi-walled carbon nanotubes (MWNTs) and those modified by atmospheric pressure dielectric barrier discharge (DBD) air plasma at different times (30, 60 and 120 s) for H2S and SO2, respectively. The results show that the sensitivity and response time of modified MWNTs to H2S are both improved, whereas the opposite effects are observed for SO2. The modified MWNTs have almost zero sensitivity to SO2. Thus, the MWNTs modified by atmospheric pressure DBD air plasma present good selectivity to H2S, and have great potential in H2S detection.
«The World Unplugged» and «24 Hours without Media»: Media Literacy to Develop Self-Awareness Regarding Media
Authors: Moeller Susan , Powers Elia , Roberts Jessica
Published: July 2012

Across the globe, many students have easy and constant access to media, yet they often receive little or no instruction about the impact of their media consumption. This article outlines a «24 hours without media» exercise in accordance with the guidelines set in Module 7, Unit 1 of the UNESCO curriculum. In the fall of 2010, nearly 1,000 students from a dozen universities across five continents took part in «The World Unplugged» study. Researchers at the University of Maryland gathered students’ narrative responses to the going without media assignment and analyzed them by using grounded theory and analytic abduction, assisted by IBM’s ManyEyes computer analysis software. Results showed that going without media made students dramatically more cognizant of their own media habits –with many self-reporting an «addiction» to media– a finding further supported by a clear majority in every country admitting outright failure of their efforts to go unplugged. Students also reported that having constant access to digital technology is integral to their personal identities; it is essential to the way they construct and manage their work and social lives. «The World Unplugged» exercise enabled experiential learning; students gained increased self-awareness about the role of media in their lives and faculty came to better understand the Internet usage patterns of their students, enhancing their ability to help young people become more media literate.

La mayoría de los jóvenes del mundo se conecta habitualmente a los medios de comunicación; sin embargo, en pocas ocasiones reciben formación respecto a los impactos que este consumo mediático tiene en ellos mismos. Este artículo expone la experiencia llevada a cabo en el marco del Currículum UNESCO, denominada «24 horas sin medios». En otoño de 2010, cerca de 1.000 estudiantes de 12 universidades de cuatro continentes participaron en el estudio «El mundo desconectado». Investigadores de la Universidad de Maryland (Estados Unidos) recogieron rigurosamente las reflexiones de los alumnos que participaron y las analizaron a través del programa estadístico IBM’s ManyEyes. Los resultados muestran que los jóvenes, a raíz del ejercicio, fueron más conscientes de sus hábitos mediáticos, y muchos de ellos indagaron sobre su propia «adicción» a los medios, mientras que otros no consiguieron siquiera concluir estas 24 horas sin medios. También se pone en evidencia que el acceso cotidiano a la tecnología digital forma parte ya de su identidad juvenil y son básicas para entender su forma de trabajar y sus relaciones sociales. También se demuestra que los alumnos aumentaron su autoconciencia sobre el papel de los medios en sus vidas, y el profesorado comenzó a comprender mejor los intereses de sus alumnos, así como sus parámetros de consumo de Internet, mejorando sus habilidades para ayudar a los jóvenes a estar más alfabetizados mediáticamente.
Synchronous Virtual Environments for e-Assessment in Higher Education
Authors: Yuste-Tosina Rocío , Alonso-Díaz Laura , Blázquez-Entonado Florentino
Published: July 2012

This research studies an assessment system of distance learning that combines an innovative virtual assessment tool and the use of synchronous virtual classrooms with videoconferencing, which could become a reliable and guaranteed model for the evaluation of university e-learning activities. This model has been tested in an online course for Secondary School Education Specialists for Spanish, Portuguese and Latin American graduates. The research was designed from a qualitative methodology perspective and involved teachers, students and external assessors. During the whole process great care was taken to preserve data credibility, consistency and reliability, and a system of categories and subcategories that represents online assessment has been developed. The results confirm that we have made considerable progress in achieving a viable, efficient and innovative educational model that can be implemented in Higher Distance Education. Also, videoconferencing and synchronous virtual classrooms have proved to be efficient tools for evaluating the e-assessment method in virtual learning spaces. However, we need to keep testing this model in other educational scenarios in order to guarantee its viability.

En el presente trabajo de investigación se somete a estudio un sistema de evaluación de los aprendizajes en enseñanza a distancia en el que, combinando un tipo de evaluación virtual pedagógicamente innovadora y el uso de aulas virtuales síncronas, con videoconferencia, pueda acreditarse un modelo fiable y garante de evaluación de los procesos de enseñanza/aprendizaje para actividades de e-learning universitarias. El modelo se ha probado en un curso online de Especialista en Educación Secundaria dirigido a titulados universitarios españoles, portugueses y latinoamericanos. Desde una perspectiva metodológica cualitativa, se diseñó una investigación cuyos participantes han sido el profesorado y el alumnado protagonistas de la formación, así como evaluadores externos. Durante todo el proceso se han cuidado especialmente los aspectos relacionados con la credibilidad, consistencia y confirmabilidad de los datos obtenidos, extrayendo de modo inductivo un sistema de categorías y subcategorías que representan la evaluación de los aprendizajes en procesos formativos online. Los resultados confirman que se ha avanzado en la consecución de un modelo innovador de e-evaluación viable, eficaz y que garantiza su aplicación en enseñanza superior a distancia. Asimismo, el uso de videoconferencias y de las aulas virtuales síncronas para realizar entrevistas de eevaluación ha resultado ser un instrumento eficaz en espacios virtuales de aprendizaje. De cualquier modo, se evidencia la necesidad de continuar experimentando este modelo en otros escenarios educativos.
Vanaf Ockham na Kusa: Die ensiklopediese aanspraak van ‘n ‘post-skolastiek’ in die Middeleeuse filosofie
Authors: Beukes Johann
Published: July 2012

From Ockham to Cusa: The encyclopaedic case for ‘post-scholasticism’ in Medieval philosophy. This article argues for the encyclopaedic recognition of ‘post-scholasticism’, indicating the very last and complex period (circa 1349–1464) in late Medieval philosophy, where the via moderna and logica modernorum have clearly departed from the fundamental premises of high scholasticism, the via antiqua and the logica novus, as manifested in the work of William of Ockham (and, eventually, in the political theory of Marsilius of Padua). The article argues that post-scholasticism should be distinguished from late scholasticism (exiting Ockham) and early Renaissance philosophy (entering Nicholas of Cusa). The article indicates that there is a tendency in many introductions to and secondary texts in Medieval philosophy to proceed straight from Ockham to Cusa (the ‘very last Medieval and very first Renaissance philosopher’), understating more than a century of pertinent Medieval scholarship. In the modern encyclopaedia of philosophy, this understatement manifests in either a predating of Renaissance philosophy to close the gap between Ockham and Cusa as far as possible, or in understating this period as philosophically sterile, or in, without argument, simply proceeding straight from Ockham to Cusa. The article covers some of the essential philosophical contributions presented during this fragile philosophical-historical period, indicating that post-scholasticism is indeed a difficult and complex, yet productive period in the history of late Medieval philosophy, which should not be bypassed as a trivial gateway to either Renaissance philosophy or early modernity as such, but valued for its own idiosincracies, intricacies and overall contribution to the history of ideas in philosophy and theology.
An Optimal Transport View of Schrödinger's Equation
Authors: von Renesse Max-K.
Published: July 2012

We show that the Schrödinger equation is a lift of Newton's third law of motionon the space of probability measures, where derivatives are taken with respect to the Wasserstein Riemannian metric. Here the potentialμ→F(μ) is the sum of the total classical potential energy (V, μ) of the extended system and its Fisher information. The precise relation is established via a well-known (Madelung) transform which is shown to be a symplectic submersion of the standard symplectic structure of complex valued functions into the canonical symplectic space over the Wasserstein space. All computations are conducted in the framework of Otto's formal Riemannian calculus for optimal transportation of probability measures.
Épistémologie et probabilité chez Keynes
Authors: Muchlinski Elke
Published: July 2012

Cet article propose une analyse épistémologique de la théorie des probabilités de Keynes. Il concerne plus particulièrement le lien entre la conception keynésienne des probabilités et la théorie économique élaborée par Keynes. Nous montrerons que Keynes s’oppose à l’esthétisme formel, aux lois rigides et à la théorie orthodoxe en raison de sa prétendue universalité spatio-temporelle. Nous verrons que Keynes substitue aux catégories traditionnelles, entre autres celles de rigueur et de connaissance complète, de nouvelles catégories comme celles d’incertitude, d’ignorance et d’anticipation. Étant donné que Keynes rejette d’entrée de jeu les calculs du type ce ceux que l’on retrouve dans les approches inspirées de Bentham, nous ferons voir que sa théorie économique prend en compte la fragilité et la précarité de la connaissance. Nous insisterons enfin pour dire que Keynes nous paraît également dépasser le constructivisme, car il rejette ouvertement le recours aux concepts vides, à savoir ceux qui ne sont pour lui qu’un squelette sans chair. Enfin, nous mettrons en évidence que, poussé par le besoin de se fonder sur des principes validesa priori, Keynes abandonne l’empirisme classique à son sort.
Les grandeurs fondamentales de la Théorie générale
Authors: Rosier Michel
Published: July 2012

La Théorie générale emprunte certains de ses concepts fondamentaux à la comptabilité privée, en particulier : le revenu de l’entrepreneur et l’opération qui consiste à affecter une part de ce revenu à l’autofinancement (amortissements, provisions et réserves), c’est-à-dire l’épargne des entreprises. Ces deux concepts sont ignorés par les interprètes de Keynes. Pourtant, ils sont nécessaires pour comprendre pourquoi une dépense d’investissement crée une épargne égale, pourquoi une telle dépense est susceptible d’enclencher un processus de multiplication, et comment un autofinancement trop important peut être la cause d’une crise.
Quand un et un ne font plus deux
Authors: Vermeulen Frederic , Watteyne André
Published: July 2012

Dans cet article, nous présentons un modèle collectif avec consommation publique. Ce modèle est basé sur celui, plus général, de Browning, Chiappori et Lewbel (2004). Au lieu d’estimer une technologie de consommation, qui capte toutes les économies d’échelle liées à la vie en couple, nous déterminons a priori les biens qui sont consommés de façon privée et ceux qui le sont de façon publique. Le modèle collectif en question est complètement identifié si l’on suppose que les préférences relatives aux biens privés et publics sont les mêmes pour qui vit en couple que pour qui vit seul. Le modèle nous permet de calculer des échelles d’équivalence applicables au sein du ménage. Ainsi, on échappe aux critiques formulées à l’encontre des échelles d’équivalence traditionnelles. Le modèle est appliqué aux données sur la consommation tirées de trois enquêtes de budget belges récentes.