bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of Localized Gingival Recessions Using Gingival Unit Grafts: A Randomized Controlled Clinical Trial
Authors: Kuru Bahar , Yıldırım Selin
Published: March 2012

Background: One of the success factors in periodontal plastic surgery is the synergistic relationship between involved tissues and vascular supply. Gingiva as a functional unit is unique with a specific vascular configuration and contains the supracrestal portion naturally created to survive over avascular root surfaces. The aim of this randomized controlled trial is to clinically evaluate the treatment of localized gingival recessions by using gingival unit grafts (palatal tissue involving marginal gingiva and papillae) compared with conventional palatal grafts.

Methods: Seventeen patients with Class I to II recession defects on mandibular anterior teeth were included and randomly divided into two groups. Recessions were treated with gingival unit grafts in group 1 (n = 8) and with palatal grafts in group 2 (n = 9). Clinical parameters including vertical recession (VR), probing depth, keratinized tissue (KT), and attachment level were recorded at baseline and 8 months after surgery.

Results: Both treatments produced significant clinical improvements within the groups. Intergroup comparison revealed significantly higher VR reduction, attachment, and KT gain in group 1 than in group 2; mean percentages of the defect coverage were 91.62% ± 9.74% and 68.97% ± 13.67%, respectively (P <0.05). Healing of the gingival unit donor site was uneventful.

Conclusion: Within its limits, this study demonstrates the possibility of treating buccal recessions with gingival unit grafts as an alternative technique using gingival donor graft of site‐specific vascular configuration, with better defect coverage, clinical, and esthetic improvements compared with palatal grafts.
Successful Qualification and Deployment of a High-Pressure Drill Pipe Riser in West Africa
Authors: Camus Mathieu , Auclair Pascal , Horsburgh Barrie , Gallois Yann , Rohart Christophe , Williams Henri , Mfoulou Yannick
Published: March 2012

The Cameron/TOTAL Usan project team brought one of the first High-Pressure Drill Pipe Riser for Intervention Systems (DPRISi) to the African deepwater market in 2009.

Since July 2010, the string has been used offshore Nigeria. A total of 20 runs have been performed with this DPRIS, resulting in the safe and efficient installation of four trees. These trees have had no cleaning issues and no rust debris impacting operations.

Proper operating procedures implemented by field personnel have allowed for safe and efficient subsea DPRIS runs to date and provide confidence in future runs (38 more trees are planned).

Before DPRIS, most operators used conventional drill pipe available on rigs to install and retrieve the production adapter base and tree cap. While success varied, difficulties and risks arose using a hydraulic umbilical inside the riser, making it evident that technological improvement was needed to minimize interference between the pipe and the hydraulic lines.

The pipe delivered as part of this project, from VAM Drilling, are drill pipe risers with a propriety double shoulder connection and featuring a gas-tight metal-to-metal seal on the inner shoulder.

The standard offer for high-pressure DPR is 6-5/8" 0.5" wt and X-95 grade. VAM Drilling suggested this be changed to have a thick wall for corrosion allowance and higher grade for tensile strength, 6-5/8" 0.625" wt and G-105 grade.

The qualification program additionally covered all remaining requirements for full compliance to ISO-13628-7, which is believed to be a good certification level for such demanding and challenging operations.

The DPRIS system delivered in West Africa is a cost-efficient solution for subsea operations, workover applications and well intervention. This successful project, which provides technical and commercial value, is an example of how to implement a successful deepwater intervention business, not only in Africa but throughout the world.
Advanced Drilling Simulation Environment for Testing New Drilling Automation Techniques
Authors: Cayeux Eric , Daireaux Benoît , Dvergsnes Erik Wolden , Leulseged Amare , Bruun Bjørn Torstein , Herbert Mike
Published: March 2012

Newly developed drilling automation systems locate a computer interface between commands issued by the driller and instructions transmitted to the drilling machinery. Such functions are capable of faster and more precise control than achieved by an unaided operator and thus can help drilling within narrow margins. To ensure that these systems work properly in all circumstances, an advanced drilling simulator has been developed to enable testing under a wide range of simulated conditions.

The environment described in this paper uses hardware in the loop simulation to verify that the automation techniques being tested respond correctly in real-time. Rigorously validated physical models of the drilling process simulate the response of the well to the commands given to the drilling machines. Abnormal drilling conditions (pack-offs, kicks, etc.), and equipment or machine related problems (plugged nozzles, power shortage, etc.) are convincingly recreated.

The drilling simulator models the behavior of surface equipment like the activation of gate valves to line up different pits or the flow in the mud return. It simulates changes in the drilling fluid properties when mixing additives to the mud. It is therefore possible to focus training sessions on cooperation between different groups at the wellsite. This is particularly useful when planning the introduction of drilling automation that involves new work procedures as a result of automation and adaptation of the drilling team to a new operational environment.

Drilling operations are becoming more and more complex. Automation has the potential to provide large improvements in efficiency and safety, but automation technologies must be implemented correctly at the workplace. In the same way as the aviation industry has utilized simulated environments for decades, drilling simulation environments are the key to the safe and successful implementation of drilling automation and the development of crew skills to face future challenges.
Applying Theoretical Control Strategies for ROP Optimization and Offshore Well Costs Mitigation
Authors: Folsta M. G. , Martins A. L.
Published: March 2012

Process control strategies are widespread in the industry and provide cost reduction and reliability for different processes. Automation for Well construction technology is still an emerging technology, most probably due to data transmission limitations and to the several uncertainties inherent to the process. The elevated costs, especially in deepwater operations, and the society claims for safety improvement are the major drives for the increasing industrial efforts to overcome the steps for drilling automation. Several process can be controlled during well construction steps, such as: downhole pressure and torque on bit during drilling, bit cost minimization, keeping downhole pressures during influx circulations and tripping. The purpose of this article is to show a comprehensive analysis of the adequacy of different process control strategies to support the automation of the drilling process, with special focus on cost reduction. Initially, a traditional feed back approach was considered to compare different control methodologies, such as Proportional (P), Proportional-Integral (PI) and proportional – Integral- Differential (PID). Comparison in response times, attenuation rates and other control parameters are presented. Control stability performance was evaluated through the analysis of measurement and actuation delays, signal loss, magnitude of disturbs and other classic strategies.
Uncertainty Quantification of Real-Time Pore Pressure Models Caused by Normal Compaction Trend Line Setting
Authors: Bartetzko Anne , Wessling Stefan , Tesch Philipp , Lautenschläger Ulrike , Andonof Luis , Broadhead Daniel
Published: March 2012

Pore pressure related wellbore instability is a recognized drilling challenge requiring attention as early as possible to mitigate and remediate severe drilling hazards such as kicks. Methods exist to quantify the effects of certain input parameters on pore pressure models, but the effect of the different, partly manual stages in pore pressure modeling on the uncertainty has rarely been addressed in the past.

This paper highlights uncertainty sources associated with the basic stages in pore pressure modeling: shale discrimination using the gamma ray log and definition of the normal compaction trend line, either manually or using a regression analysis. Furthermore, filtering of the data prior to trend line definition may also add to some amount of uncertainty. These uncertainties in pore pressure prediction introduced by the modeling stages is demonstrated on an example data set from an offshore well. In particular, we show that applying different shale discrimination approaches can introduce pore pressure variations. Furthermore, a variation in depth intervals over which the trend line is automatically determined by linear regression can add more uncertainty to the pore pressure model.

An approach is presented to quantify pore pressure uncertainty by automatically analyzing the variation in normal compaction trend lines. The application of the proposed method aims to constrain and quantify the error associated in modeling pore pressure in real-time, based on surface and subsurface (MWD and LWD) data. Modeling both pore pressure and its uncertainty creates additional value for safer drilling, because rig and remote monitoring personnel are made aware of a dynamic updated pore pressure range in addition to the possible pressure regimes interpreted during pre-drill modeling.
Automation Improves Shaker Performance
Authors: El Dorry Khaled , Dufilho Bill
Published: March 2012

One of the limitations of current shale shakers is that their performance can be negatively impacted by changes in the feed rate. Standard shakers operate with vibratory motors running at a constant speed, yielding a constant output force. This results in a shaker having its peak g-force during non-loaded conditions. As soon as drilling fluid is added to the system (more mass), the acceleration (g-force) decreases and in turn, the shaker performance decreases as well.

A significant improvement for shale shakers has been achieved with the introduction of the second generation of the controlled acceleration technique. The improved technology allows the shaker to continuously adjust the shaker basket’s g-force to the proper pre programmed set point. This improvement offers significant advantages over the first generation of controlled accerletion in terms of performance, cost, safety and downtime.

Field tests have shown that a shaker equipped with the second generation of controlled acceleartion is still capable of screening 2 API classes finer or better as is the case with the first generation. Use of this technology allows for improved solids removal efficiency and the potential to reduce rig non-productive time (NPT) and improve rate of penetration (ROP) by helping to yield a cleaner wellbore.

Presented will be the differences between the first and second generations of controlled acceleration along with field and theoretical data showing performance curves.
Analytical Model to Predict the Effect of Pipe Friction on Downhole Temperatures for Extended-Reach Drilling (ERD)
Authors: Kumar Aniket , Singh Ajay Pratap , Samuel Robello
Published: March 2012

The advent of extended-reach drilling (ERD) has led to increased effects of friction on the drillstring and the drilling fluid. Wellbore mechanical friction attributable to pipe rotation or to torque and drag plays a significant role in drilling operations and is considered to influence the temperatures downhole. An analytical mathematical model will help to provide physical insight to understand the borehole conditions.

This study aims to develop a simple mathematical model to analyze the heat generated from borehole friction and to predict the temperature of the drilling fluid during a drilling operation at any depth in the well. The model presents a steady-state solution for heat transfer between the drillstring and the fluids in the drillpipe and annulus, as well as heat transfer between the annular fluid and the formation. Heat generated from friction has been modeled using the torque acting on the drillstring as a result of contact forces. A linear temperature gradient for the formation and a constant borehole wall temperature has been assumed to simplify the model. Frictional pressure losses in the drill pipe, in the annulus, and across the bit have been incorporated in the model because they contribute to the heat generated in the borehole.

This paper will present the derivations of the generalized heat transfer model and the application of the model in a field case. The temperature of the drilling fluid has been calculated both in the annulus as well as inside the drillpipe at various depths for the considered well profile. The drillstring temperature profile has been estimated using the calculated drilling fluid temperatures. Wellbore mechanical friction and downhole temperatures were thoroughly studied by varying the underlying drilling parameters in the model.
Automation in Drilling: Future Evolution and Lessons from Aviation
Authors: Thorogood J. L.
Published: March 2012

Automation of the drilling process has been gathering pace over the last 10 years, with progress being made on many fronts, from choke control in managed pressure drilling (MPD) operations, through a new generation of auto drillers to intelligent systems that prevent the driller from exceeding parameters that might cause downhole problems.

Observing the current state of automation in drilling, it is clear that in the case of MPD, automation has resulted in closer and more stable control of a process that can be achieved by a manual system. Auto-drillers combined with downhole rotary steerable systems have resulted in improved progress rates compared to manual systems. By contrast, modern rigs with highly mechanised pipe handling systems are still controlled manually with a crewing arrangement that has changed little while the technology has evolved dramatically. These developments pose a number of questions, for example:

In what direction is automation likely to evolve in the future, and why? Can the drilling community avoid the mistakes of other industries and how might this be prevented?

The paper reviews developments of automation in aviation and describes some of the problems that have arisen. It then outlines the analogous efforts in drilling and identifies lessons that could be learned. The paper presents a rationale on which further automation initiatives might be based and some of the related changes that might be necessary as a result.
Development of a New Advanced Multiple Activation System for Concentric Underreamers
Authors: Torvestad Bjørn Tore , Ray Tom , Hu Jianbing , Gjertsen Ole Jacob , Muir Michael
Published: March 2012

Hole Enlargement While Drilling (HEWD) using a concentric underreamer is a widely used technique for efficient wellbore construction. Most underreamers are fitted with lock-out systems to provide a means of drilling out the shoe-track with the cutters close before enlarging the borehole below casing. Several vendors also provide a system to lock the tool closed after reaching total depth (TD) to enable full flow while pulling out of the hole for best possible wellbore cleaning.

However, most available underreamers cannot be reactivated after deactivation. Another limiting factor is that the tools must be placed on top of the Bottom Hole Assembly (BHA) due to the ball drop activation method.

To solve the problem, a new system has been developed that makes it possible to perform multiple activation/deactivation of the underreamer. The most obvious advantages are infinite open/close cycles for selective underreaming and the more flexible placement opportunities within the BHA due to the activation method. Other advantages are time saving through the elimination of several runs, shorter activation time and higher flow rate capabilities.

Several successful tests in realistic drilling environments were performed prior to starting the field testing program. Through the field testing stage the system has performed as planned under normal drilling conditions and has a significant cost saving potential for the operator. The authors will discuss the application challenges, benefits, features and engineering efforts including field testing, that led to a commercial Ream on Demand (ROD) system.
Multilateral History - Deepest Level 4 Cemented Junction Installation
Authors: Hua An Wen , Qing Teng Xue , Tong Yang Xiang , Xiang Bai Deng , Ponton Calvin , Roberts Justin , Durst Doug
Published: March 2012

An operator was challenged with increasing production efficiencies from new single wellbores in the deep Tarim basin reservoirs of China. To increase and optimize single well production performance, multilateral drilling and completion technology were implemented on this initial pilot test well.

The remote location of the multilateral well in the Tarim Desert of the Xinjiang Province in northwestern China proved to be an operational and logistical challenge in terms of time (4 to 5 days travel by vehicle) and distance (3600 kilometers) to the nearest repair and maintenance facilities in Tanggu, Tianjin Province in eastern China. Critical planning, aggressive project management oversight, and strong collaboration between the operator and service supplier resulted in the world’s deepest TAML Level 4 cemented multilateral installation at 5082 m TVD junction depth and 5889 m MD at the lateral toe.

The well design was based on a vertical pilot well, or motherbore, drilled and cased into the reservoir. The multilateral system was then installed to add an additional wellbore, thereby increasing reservoir exposure. The goals of this system were to accelerate production, increase ultimate recovery and, for this particular operator, to qualify multilateral technology for this particular field application. Because of the unprecedented depth of the proposed junction, thorough project management and planning were required throughout, from the feasibility phase through the execution phase, to amplify risk mitigation and to effect a successful project installation.

This project is the first multilateral installation for this client; it was the first cemented Level 4 multilateral in China, and is the deepest Level 4 multilateral installed worldwide. This paper describes the objectives, challenges, best practices, contingencies, logistics issues, results, and lessons learned from the implementation of this deep-set multilateral technology.
Dynamic Modelling of Gas Distribution in the Wellbore During Kick Situations
Authors: Spoerker H. F. , Gruber C. , Brandstaetter W.
Published: March 2012

The paper presents a Computational Fluid Dynamics (CFD) simulation of the distribution of influx gas in the drilling fluid during kick situations. Special focus is put on the bottom-hole inlet region of a vertical well, with the aim of obtaining a highly resolved phase distribution. An interfacial tracking method (VOF) is used to simulate the unsteady motion of incompressible drilling fluid and compressible gas, taking into account turbulence as well as non-Newtonian rheology. This method describes both phases with a single set of equations and additionally solves an equation to calculate the local volume fraction of the phases. Hence no a priori assumptions need to be made regarding flow patterns. The result of these simulations will subsequently be used to model the chemical reaction kinetics of the buffering process between H2S influxes and high-pH drilling fluid environments.
From Field Test to Successful Integration of Broadband Drillstring System for Offshore Extended Reach Wells
Authors: Veeningen Daan , Palmer Jason , Steinicke Greg , Saenz Jesus , Hansen Troy
Published: March 2012

High-angle offshore wells in Trinidad and Tobago are characterized by hole cleaning challenges, wellbore instability, and downhole vibrations damaging both tools and drill bits. To reduce operational risks and improve project economics, the operator selected a multi-well campaign to implement a wired pipe or broadband networked drillstring system. The broadband network system provided high resolution data from downhole tools and along string annular pressure evaluation in real time for approximately 97% of the 75,000ft drilled during the trial period.

The project achieved a significant decrease in wellbore instability related to non-productive time, as well as higher tool reliability through downhole diagnostics, improved hole cleaning, and stick-slip vibration mitigation.

This paper describes the successful implementation of high-definition downhole operations through project management, collaboration with third party tool partners and resourceful scalable solutions to solve operational and logistical challenges. Lessons learned include the implementation on two rigs, data swivel installations, the commissioning of a shorebase and the pioneering of local repair and maintenance for specialized networked drilling tools, all leading to the complete integration into the customer’s workflow and process.
Effective Force and True Force: What are They?
Authors: Samuel Robello , Kumar Aniket
Published: March 2012

The predictions of hookload, tension, and stresses are important for the successful completion of any well operation, as well as for the selection of optimum operating parameters. The terms effective axial force and true force or effective tension and true tension are used for various tubular designs, including riser designs. To further complicate matters, they are also defined as buoyancy and pressure area methods of calculating forces. Discussions of these two forces occasionally raise doubts regarding how to treat the internal and/or external pressures. The main problem stems from the perception that effective force as a fictitious force, and the inclusion of the internal and external pressures as counter intuitive source of misunderstandings and wrong designs. Although several authors have used the calculation and concepts correctly, other previously published papers failed to address the issue clearly and in a simple way; as a result, confusion still exists. These two forces further result in two neutral points, which raises the questions of “when you apply pressure, does the neutral point change?” and “which neutral point should be used for stuck pipe calculations?” The working envelop using yield limit with combined loading of uniaxial force and pressure forces are important. Using the wrong force/tension will result in an incorrect interpretation of the burst and collapse limits. This paper provides the mathematical treatise and discusses the theoretical basis of these two forces, including how they are used in torque, drag, buckling, stress, and limit calculations. This paper describes the details, apparent definition, pitfalls, and context in which these forces can be used. Simple guidelines are presented, as well as several example calculations to help explain various tubular modeling aspects for future generations of drilling engineers.
Drilling Automation: Potential for Human Error
Authors: Iversen Fionn , Gressgård Leif Jarle , Thorogood John , Balov Mohsen Karimi , Hepsø Vidar
Published: March 2012

Mode confusion is when an automated system behaves differently than expected; in such a way that the operator is not aware of or does not properly understand what the system is doing. Mode confusion is well recognized in the aviation community and has been indicated in a number of high profile aviation accidents. As an example, a Jas Gripen fighter jet crashed during a test flight in the 1980s due to the pilot trying to manually correct instability while the plane's computer was automatically trying to do the same. The potential for the same type of problems, and associated safety hazards, arises in drilling rig operations as a result of the increasing trend for automation and advisory systems. A simple example could be formation fracturing with an automated ECD control system when displacing to higher mudweight caused by the driller relying on the automated system to maintain sufficiently low flowrate without having reconfigured the system with the new mud properties. Through the reported study the authors wish to analyse how use of a drilling support system in different modes and levels of automation may influence the system operator's performance and risk of human error. Development of a systematic method for detecting mode confusion problems by model checking is central in this respect. The test cases have been simulated in a synthetic test environment created at IRIS specifically for such purposes. The test environment and test cases are described, and results are reported and discussed.
Continuing Efficiency and Assurance Advances for Deepwater BOP Testing
Authors: Franklin C. Mark , Cully Rick
Published: March 2012

Recently, a significant advancement in deepwater BOP leak detection was introduced through an industry sponsored software development project. This application combined innovative algorithms for validating pressure tests with an intuitive user interface for test plan management, testing and reporting. The results have validated the application’s ability to achieve accurate and objective test results with a significant increase in testing clarity and leak detection efficiency. While widespread implementation presented some obstacles, such as dealing with rig motion and complex new pumping systems, these challenges were overcome. With the experiences and suggestions gathered over the past two years, the application has advanced to new levels of assurance and functionality. This paper provides a functional review of the application and significant advancements achieved over the last year.

In addition to utilizing the application to plan, conduct and report BOP pressure tests accurately, objectively and efficiently, rigs can now utilize a customized interactive schematic feature, modeling the rig’s BOP and manifold within the application. Working interactively with this model, users have the ability to optimally design tests by simply clicking on valves, rams and annulars ("components") to open or close them and visualize the resulting pressure test path. The same methodology is used to define the objectives of a test plan ("component coverage") by selecting required valve sides and BOP rams, annulars and pipe sizes.

Throughout planning phase a visual representation of each test step is provided, including clear identification of pressure paths and component coverage. During tests, real-time updates automatically and continuously inform users of test coverage progress. Comprehensive reports ensure clear and concise communication of test plans, valve alignments and test results.
Revolutionizing Drilling Performance through Advanced Real Time Performance Advisory System
Authors: Dow B. , Harmer R. , Belaskie J.
Published: March 2012

The industry continues to apply scientific methods searching for drilling performance improvement. Advanced applications aimed at rate of penetration (ROP) improvement, bottom hole assembly (BHA) longevity through performance management and lost time avoidance through early event detection have evolved as downhole and surface data continue to become more robust. Applying this science to actually improve well construction requires a workflow that enables the operations team to respond to the data in a timely manner. The driller is the most influential person in the performance improvement workflow, yet drilling performance ranks down the list of priorities, rightfully so, behind well control, crew safety and rig equipment operations. Successful well construction improvement requires a tool that delivers timely advice to the driller, enabling performance improvement without distracting from other priorities.

This paper will discuss the development and field application of a new technology that allows data to be turned into actions at the well site, improving overall well construction performance. The development team applied a rich understanding of existing wellsite workflows, technology and workplace ergonomics and key attributes from gaming and telecommunications industries. The end result is a piece of technology that brings together several performance improvement analytical tools developed over years of research and development into one console, turning data into clear directions for the driller, and delivering performance improvement feedback immediately.

Results, Observations, Conclusions: Field data from 10 wells throughout the world show how the system has been used to reduce well construction time by more than 20%. The radical new way of presenting data to the driller was a significant key to success. The software development platform allowed for quick feedback throughout field testing, integrating user input to continuously evolve the best fit-for-purpose application.
Photosynthetic bacteria production from food processing wastewater in sequencing batch and membrane photo-bioreactors
Authors: Chitapornpan S. , Chiemchaisri C. , Chiemchaisri W. , Honda R. , Yamamoto K.
Published: March 2012

Application of photosynthetic process could be highly efficient and surpass anaerobic treatment in releasing less greenhouse gas and odor while the biomass produced can be utilized. The combination of photosynthetic process with membrane separation is possibly effective for water reclamation and biomass production. In this study, cultivation of mixed culture photosynthetic bacteria from food processing wastewater was investigated in a sequencing batch reactor (SBR) and a membrane bioreactor (MBR) supplied with infrared light. Both photo-bioreactors were operated at a hydraulic retention time (HRT) of 10 days. Higher MLSS concentration achieved in the MBR through complete retention of biomass resulted in a slightly improved performance. When the system was operated with MLSS controlled by occasional sludge withdrawal, total biomass production of MBR and SBR photo-bioreactor was almost equal. However, 64.5% of total biomass production was washed out with the effluent in SBR system. Consequently, the higher biomass could be recovered for utilization in MBR.
Evaluating the effects of nitrogen loading rate and substrate inhibitions on partial nitrification with FISH analysis
Authors: Zhang Liang , Zhang Shujun , Han Xiaoyu , Gan Yiping , Wu Chengcheng , Peng Yongzhen
Published: March 2012

The effects of free ammonia (FA) or free nitrous acid (FNA) on partial nitrification (PN) has been well investigated. Nevertheless, little information was known about the combined effects of nitrogen loading rate (NLR) and substrate inhibition, as well as the impact on the community structure of nitrifiers. In this work, real reject water was treated in a pre-denitrification reactor. PN was achieved by gradually increasing NLR, and it was successfully maintained when average FA and FNA were within 0.8–3.2 mg NH3-N/L and 0.003–0.067 mg HNO2-N/L, respectively. When NLR was reduced, PN was slightly affected due to the FA declination. As FNA inhibition was also eliminated by adding alkalinity into the influent, PN was completely destroyed quickly. FISH results indicated the deterioration of the PN was mainly attributed to the recovery of NOB when inhibition effects were limited. It concluded the increase of NLR benefited the partial nitrification. However, the stability of the nitrite path way was more dependent on selective substrate inhibition effects, especially the FNA inhibition. These findings would be important for further treatment of actual reject water.
Electrogeneration of aluminium to remove silica in water
Authors: Gelover-Santiago S. L. , Pérez-Castrejón S. , Martín-Domínguez A. , Villegas-Mendoza I. E.
Published: March 2012

This paper presents the results of a study on electrogeneration of aluminium, as a coagulant to remove silica in make-up water for cooling towers. Three electrochemical systems were tested, two with aluminium electrodes (one with polarity change and another without it), and a third one with aluminium anodes and cathodes of stainless steel. From the obtained results it was concluded that under the studied conditions, the most advantageous system to produce aluminium and remove silica is the one with both electrodes of aluminium working with direct current. Due to chemical production of aluminium at the cathode, the concentration of aluminium in the water at the outlet of the electrochemical reactor is much higher than the one calculated according to Faraday's law. Under the tested conditions it was possible to remove up to 66% of silica from water containing around 50 mg L−1.
Full-scale operating experience of deep bed denitrification filter achieving <3 mg/l total nitrogen and <0.18 mg/l total phosphorus
Authors: Husband Joseph A. , Slattery Larry , Garrett John , Corsoro Frank , Smithers Carol , Phipps Scott
Published: March 2012

The Arlington County Wastewater Pollution Control Plant (ACWPCP) is located in the southern part of Arlington County, Virginia, USA and discharges to the Potomac River via the Four Mile Run. The ACWPCP was originally constructed in 1937. In 2001, Arlington County, Virginia (USA) committed to expanding their 113,500 m3/d, (300,000 pe) secondary treatment plant to a 151,400 m3/d (400,000 pe) to achieve effluent total nitrogen (TN) to <3 mg/l and total phosphorus (TP) < 0.18 mg/l. Key to this conversion was the implementation of deep bed denitrification filters to simultaneously achieve both low effluent TN and TP concentrations. A challenge with implementing this technology is maintaining a health denitrifying biomass within the denitrification filters while reducing an essential nutrient, phosphorus, to very low concentrations. This paper will review the steps from concept to the first year of operation, including pilot and full-scale operating data and the capital cost for the denitrification filters.
Urban Education and Segregation: The Responses from Young People
Authors: Öhrn Elisabet
Published: March 2012

This article takes as a starting point the segregation of urban areas and discusses schooling in the neighbourhoods typically associated with problems and challenges, in order to explore young people's responses to their schooling and social positions. Such responses include individual acts, such as rejecting further schooling or dismissing the local school in favour of prestigious ones, as well as the development of shared understandings and collective formations. The article focuses in particular on young people's responses through aesthetic practices, informal education and public political actions. Although research suggests that youths in poor areas are increasingly individualised and shows that schools provide them with little help to understand and act upon their circumstances in school, the analyses here also bring to light young people's rather strong belief in collective actions; students' formations of resistance groups and political knowledge appear as crucial resources, and, although scarce, teacher support and teaching about political actions appear as important.
An Exploration of Differences in Mathematics Attainment among Immigrant Pupils in 18 OECD Countries
Authors: Shapira Marina
Published: March 2012

This article presents findings from a comparative study of sources of educational disadvantage of immigrant children across 18 OECD countries, which is based the data from the 2006 Programme for International Student Assessment (PISA). The findings show that disadvantaged family background and lack of host-country-specific cultural capital account for a large part of the attainment gap between immigrants and their non-migrant peers. The findings also show that school characteristics in terms of their size, quality of teachers and educational resources contribute to the understanding of the further part of the immigrant performance gap. Moreover, school characteristics mediate between the immigrant students' family characteristics and their attainment, by reinforcing or diminishing the impact of the family characteristics. Furthermore, the institutional characteristics of immigration countries, such as type of education provision, type of welfare provision and type of immigration policy, also play a part in producing and maintaining educational disadvantage of immigrant pupils, by affecting the attainment level and mediating between the individual- and school-level characteristics and pupils' attainment. It was found that the first generation of immigrant children perform particularly well in countries with a liberal type of welfare regime, more standardised educational systems and more selective immigration policies; there was also some evidence that institutional factors shape educational attainment of the second generation of immigrant children in a way which more closely resembles that of the children from non-immigrant backgrounds — the former perform better in countries with a more inclusive (social-democratic) type of welfare provision, but also in countries with less differentiated and more standardised educational systems.
Pediatric Anaplastic Lymphoma Kinase–Positive Large B-cell Lymphoma: A Case Report and Review of the Literature
Authors: Yin Wei-Hua , Guo Na , Tian Xiao-Ying , Li Yang , Li Zhi
Published: March 2012

We present a case of pediatric anaplastic lymphoma kinase–positive large B-cell lymphoma (ALK-positive LBCL) with a cervical, mesentery, and pelvis cavity mass. Histologic examination of the cervical mass revealed that the lesion was composed of diffuse large immunoblastic-like or plasmablastic-like tumor cells with a sinusoidal growth pattern. The tumor cells were strongly immunoreactive for ALK; revealed a granular cytoplasmic distribution; and were diffusely positive for CD45, CD4, CD138, epithelial membrane antigen, and multiple myeloma oncogene-1 but negative for CD20 and CD79a. The patient underwent 5 courses of cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposid and obtained a remarkable clinical response with regression of mesentery and pelvis cavity mass. We suggest that this distinct subtype of large B-cell lymphoma should belong to the spectrum of pediatric lymphomas and that radiologic examination should be performed to inspect the progression of disease even if the patients experienced complete remission at initial chemotherapy.
Palestinian Working Women in Israel
Authors: Daoud Suheir Abu Oksa
Published: March 2012

The paid labor force participation of women in Arab states has always been among the lowest in the world. The same is true for Palestinian Arab women who are citizens of Israel. In sharp contrast, the paid labor participation of Jewish women in Israel is among the highest globally. This paper looks at the consequences of Israeli policy and changing social norms on the Palestinian minority in Israel through the prism of female Palestinian activism in Israel’s economy. In particular, it examines the causes, consequences, and changes in the labor force participation of Palestinian women citizens in Israel. Drawing on fieldwork and interviews with some of these women, this paper also examines the impact of their newfound earning power on social attitudes and the division of labor in their homes.
A Call to Duty
Authors: Esqueda Monica Christina , Astor Ron Avi , De Pedro Kris M. Tunac
Published: March 2012

More than 90% of the nation’s 1.2 million military children attend civilian-operated public schools. Education researchers, however, often overlook the educational experiences and needs of military children attending civilian-operated public schools (i.e., schools that are administered by and under the purview of local education agencies). This article is the first in an educational research journal to examine the intersections among state policy, school reform, and the educational experiences of military children. This article also highlights new data sources and funding opportunities for research on military students.
When Rater Reliability Is Not Enough
Authors: Hill Heather C. , Charalambous Charalambos Y. , Kraft Matthew A.
Published: March 2012

In recent years, interest has grown in using classroom observation as a means to several ends, including teacher development, teacher evaluation, and impact evaluation of classroom-based interventions. Although education practitioners and researchers have developed numerous observational instruments for these purposes, many developers fail to specify important criteria regarding instrument use. In this article, the authors argue that for classroom observation to succeed in its aims, improved observational systems must be developed. These systems should include not only observational instruments but also scoring designs capable of producing reliable and cost-efficient scores and processes for rater recruitment, training, and certification. To illustrate how such a system might be developed and improved, the authors provide an empirical example that applies generalizability theory to data from a mathematics observational instrument.
Histological Observations in Testes of Hybrids of Gallus Gallus x Phasianuns Colchicus
Authors: Castillo Annelisse , Marzoni Margherita , Pirone Andrea , Romboli Isabella
Published: March 2012

This study performed a histological and morphometric investigation of testes in Gallus gallus x Phasianus colchicus hybrids during the seasonal reproductive period of pheasants. The trial was conducted on seven 4-year old birds originated from the mating between New Hampshire cocks and female common pheasants. After sacrifice, testes were removed, macroscopically evaluated and routinely processed for light microscopic investigations. Mean testis weight was 0.85 g and a great variability was observed between birds. Only one bird out of seven developed heavier testes each weighing almost 3g. Relative volume occupied by seminiferous tubules was 75%. Approximately 39m of seminiferous tubules were found per testis and around 96 m per gram of testis. A high correlation was observed between the number of Sertoli cells and germ cells with testis weight. Seminiferous epithelium comprised Sertoli cells and germ cells at different stages of development. Three birds presented tubules with a multilayered epithelium and germ cells developed until the stage of round spermatids. Surprisingly, one bird presented some elongated forms as well.
Breeding Biology of the White-Rumped Swallow (Tachycineta Leucorrhoa; Hirundinidae) in a Wetland: A Comparative Approach
Authors: Lorenzón Rodrigo E. , Quiroga Martín A.
Published: March 2012

We studied the reproductive biology of the White-rumped Swallow (Tachycineta leucorrhoa) in a colony of 50 nests boxes located in a wetland of the Paraná River, Santa Fe, Argentina between 2004 and 2006. The nest boxes were checked regularly and reproductive parameters, as well as morphological data of eggs and nestlings, were recorded. The species had an average clutch size of 4.7 eggs whose volumes and weight means were 2.04 cm3 and 2.17 g. respectively. The incubation period averaged 15.9 days and decreased with the clutch size. The mean nestling period was 23.8 days. Clutch size, number of nestlings per nest and the nestling period decreased with the advance of the breeding seasons, while the incubation time increased. Breeding parameters showed a similarity with those reported for the population from Chascomús site, although the eggs were 5% heavier, the incubation period took one more day and the reproductive success was also higher. With the closely related species Tachycineta meyeni, the studied species showed a lower clutch size. Finally, considering another closely related species Tachycineta bicolor, the White-rumped Swallow showed the reproductive life history traits characteristic of species in the southern hemisphere. We provide new information for this species nesting on wetlands, a fact that contributes to the understanding of changes in the life history of the Tachycineta genus along the American continent.
Reading and Reflexivity: Bourdieu's Faulkner
Authors: Speller John
Published: March 2012

A rarely examined internal reading by Bourdieu at the end of The Rules of Art of William Faulkner's short story ‘A Rose for Emily’ provides the starting point for a reflection on Bourdieu's theories of reading and reflexivity. The article begins by looking at Bourdieu's theory of literary reception, and its identification of two distinct modalities of reading, ‘scholastic’ and ‘naive’. It then places Bourdieu's discussion of ‘A Rose for Emily’ as a ‘reflexive’ text in the context of his wider theory of reflexivity. Bourdieu's approach to reading Faulkner's text is compared with those deployed elsewhere by more established literary critics, notably Jean-Paul Sartre and Roland Barthes. Finally, the question of how his internal reading fits within the logic of a theoretical work devoted to the ‘reflexive’ practice and method of field analysis is discussed.
Digital Divide: How Do Home Internet Access and Parental Support Affect Student Outcomes?
Authors: Lei Jing , Zhou Jingye
Published: March 2012

This study examined the relationship between home Internet access/parental support and student outcomes. Survey data were collected from 1,576 middle school students in China. Data were analyzed using descriptive analysis, independent-samples T-test, and regression analysis. Results indicate that students who had home Internet access reported higher scores than those without home Internet on all three dimensions: Computer and Internet self-efficacy, Attitudes towards technology and Developmental outcomes. Home Internet access and parental support were significantly positively associated with technology self-efficacy, interest in technology, perceived importance of the Internet, and perceived impact of the Internet on learning. Findings from this study have significant implications for research and practice on how to narrow down the digital divide.
Coordination, Differentiation and Fairness in a Population of Cooperating Agents
Authors: Do Anne-Ly , Rudolf Lars , Gross Thilo
Published: March 2012

In a recent paper, we analyzed the self-assembly of a complex cooperation network. The network was shown to approach a state where every agent invests the same amount of resources. Nevertheless, highly-connected agents arise that extract extraordinarily high payoffs while contributing comparably little to any of their cooperations. Here, we investigate a variant of the model, in which highly-connected agents have access to additional resources. We study analytically and numerically whether these resources are invested in existing collaborations, leading to a fairer load distribution, or in establishing new collaborations, leading to an even less fair distribution of loads and payoffs.
Development of Ti-Coated Ferromagnetic Needle, Adaptable for Ablation Cancer Therapy by High-Frequency Induction Heating
Authors: Naohara Takashi , Aono Hiromichi , Maehara Tsunehiro , Hirazawa Hideyuki , Matsutomo Shinya , Watanabe Yuji
Published: March 2012

To develop a novel ablation therapy for human solid cancer, the heating properties of a ferromagnetic carbon steel rod and a prototype Ti-coated needle using this carbon steel rod, were investigated in several high-frequency outputs at 300 kHz. In the former, the heating property was drastically different among the three inclination angles (θ = 0°, 45° and 90°) relative to the magnetic flux direction as a result of the shape magnetic anisotropy. However, the effect of the inclination angles was completely eliminated in the latter. It is considered that the complete non-oriented heating property relative to the magnetic flux direction allows the precise control of the ablation temperature during minimally invasive thermotherapy without a lead-wire connected to a fiber-optic thermometer. This newly designed Ti-coated device will be suitable for clinical use combined with its superior biocompatibility for ablation treatments using high-frequency induction heating.