bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Deposition Mechanism of Mineral Scales Precipitating in the Sandface and Production Strings of Gas-Condensate Wells
Authors: Franco C.A.. A. , Solares J.R.. R. , Al-Marri H.M.. M. , Mukhles A.E.. E. , Ramadhan N.H.. H. , Saihati A.H.. H.
Published: June 2010

Thick deposits of various types of mineral scales are presently forming in the tubulars and formation of gas producers drilled in Saudi Arabian carbonate reservoirs. These mineral scales precipitate when ideal thermodynamic conditions combine with dissolved minerals present in formation waters. Without remedial action over time, these deposits can grow thicker and end up plugging tubulars and the reservoir.

Thick deposits of mineral scales have recently begun to appear in gas producers in certain areas of the field. A comprehensive study was conducted to ascertain the nature of the precipitation mechanism and identify potential solutions to the problem. This paper details how laboratory analysis data, well production history, reservoir geology and petrophysics, and reservoir description were analyzed and used with sophisticated computer software to identify the formation-damage mechanism and the different scale types precipitating in the wellbore and formation. Extensive simulation work was conducted as part of the study to forecast the type and amount of mineral-scale precipitation that can be anticipated at varying reservoir and producing conditions. The study also evaluated the most cost-effective and feasible ways to remove different types of scale deposits.

The future scale-inhibition and -removal strategies to be implemented in existing and future gas producers are being derived in large part from the results of the study described in this paper.
Modeling Formation Damage for Flow Simulations at Reservoir Scale
Authors: Ding D.Y.. Y.
Published: June 2010

Formation damage generally is limited to the immediate nearwellbore region and needs a particular near-well-flow modeling using fine gridblocks. However, near-well models are usually developed as standalone models and are decoupled from reservoir models. Using a standalone near-well model that does not take into account production scenarios cannot predict well injectivity or productivity correctly.

In this paper, we propose a new technique for the coupled modeling of a near-well-flow model and a reservoir model in a simple and consistent way. In this new approach, data are exchanged and updated through boundary conditions for the near-well model and through numerical productivity indices (PIs) (or skin factors) for the reservoir model. Examples show that this coupled modeling gives quite satisfactory results.
In-Situ Water-Blocking Measurements and Interpretation Related to Fracturing Operations in Tight Gas Reservoirs
Authors: Bazin B.. , Peysson Y.. , Lamy F.. , Martin F.. , Aubry E.. , Chapuis C..
Published: June 2010

Invasion of aqueous drilling, completion, or fracturing fluids can reduce the relative permeability to gas and thereby causes a water block. In the case of low-permeability formations, the capillary pressure tends to be high because of the small pore size. Cleanup of water blocks requires high drawdown unless water vaporization by the flowing gas is improved by using specific additives such as alcohols.

The purpose of this work is to investigate fracture-face damage by measuring relevant petrophysical parameters: absolute-permeability damage and gas return permeabilities. Measurements are performed in representative conditions of a fracturing operation in a tight gas formation: cores with an absolute permeability of 10 μd set at Swi and experimental pressure of 200 bars for the fracturing-fluid invasion. Water and gas saturations during the fracturing-fluid invasion and during gas backflow are monitored by X-ray equipment. Adding alcohol in the fracturing fluid has a striking effect on resolving water blocks. Cake formation on the simulated fracture face is also discussed.

Numerical simulations are performed to assess relative permeabilities from the experimental results. It is shown that hysteresis of gas and water relative permeabilities has a strong impact on the rate of water removal. Sufficiently high pressure drawdown is crucial to overcome capillary forces and initiate the alcohol- assisted vaporization process. Water removal by water vaporization is assessed and compared to the experimental results.
Effect of Salinity on Wettability Alteration to Intermediate Gas-Wetting
Authors: Wu Stanley , Firoozabadi Abbas
Published: June 2010

The effect of salinity on the alteration of wettability from waterwetting to intermediate gas-wetting is studied in this work. We find that NaCl salinity increases water-wetting when a core is saturated with brine. NaCl also reduces gas absolute permeability, as reported in the literature. CaCl2 salinity effect is dramatically different from that of NaCl brine and has a minor effect on permeability. The NaCl, KCl, and CaCl2 brines have an adverse effect on wettability alteration. To alleviate the effect of salt on chemical treatment, we suggest pretreatment by displacement of brine with water and subsequent drainage by nitrogen.
Spectral and Cycle-Counting Fatigue Damage Estimation Methods for Steel Catenary Risers
Authors: Power T. L. , Maniar D. R. , Garrett D. L. , Phifer E. H. , Vogiatzis J. P.
Published: June 2010

Estimating fatigue damage under wind-driven sea loading is of primary importance in the design of steel catenary risers (SCRs) serving floating hosts. For design, the wind-driven sea is modeled as a stationary random process. The resulting dynamic stress in the SCR is also a stationary random process. Spectral methods provide closed-form fatigue damage estimates in terms of statistics for stationary random stress processes. Cycle-counting methods, such as rainflow cycle counting, provide an alternative damage estimation approach that is generally applicable and requires simulation of stress time series. The cycle-counting approach requires more computation than spectral methods. Damage estimates using the cycle-counting method may be lower than spectral damage estimates; however, a substantial amount of simulation may be required to quantify the difference.

This paper considers fatigue damage in SCRs attached to both tension-leg platform and semisubmersible hosts. Spectral and cycle-counting estimates are generated and compared. Accuracy of the estimates is discussed, and guidelines for damage estimation are presented. It is demonstrated that the differences between spectral and cycle-counting estimates of lifetime fatigue damage arise primarily from assumptions made regarding the spectral shape of the stress processes of interest.
Chromatographic Partitioning of H2S and CO2 in Acid Gas Disposal
Authors: Pooladi-Darvish M. , Hong H. , Stocker R.K. , Bennion B. , Theys S. , Bachu S.
Published: June 2010

Hydrogen sulfide breakthrough in producing wells occurred after the breakthrough of CO2 in the Long Coulee Glauconite F reservoir in southern Alberta, where acid gas (98% CO2, 2% H2S) has been injected since 2002. It was hypothesized that the preferential solubility of H2S in formation brine is responsible for the delay in H2S breakthrough.

To study the chromatographic separation of H2S and CO2, a series of experiments were conducted to measure the solubility of CO2 and H2S in formation brine at in-situ conditions. Immiscible displacement experiments were performed in a slim tube packed with silica sand to study the breakthrough behaviour of different gas components. The experiments were then modelled using a compositional simulator, and the effect of different factors on the delayed breakthrough of H2S was examined using a series of sensitivity studies.

It was confirmed that the preferential solubility of H2S over CO2 leads to it being stripped off at the leading edge of the gas displacement front, resulting in its delayed breakthrough. A similar delay in H2S breakthrough occurs even at higher H2S concentrations (e.g. 30%) in the injected gas. Through the simulation studies it was shown that the delay in H2S breakthrough becomes more pronounced if the gas front is more diffusive. For example, it was shown that, when gravity forces or mobility ratio favour stable displacement, CO2 and H2S breakthroughs occur closer to each other.

This is of significance, particularly for monitoring of impure CO2 storage in deep saline aquifers, where the impurity may consist of H2S. Detection of CO2 at a monitoring well would indicate that the more noxious H2S is likely to show up after some time lag. This paper describes the experiments and the simulation studies and presents the implications of the chromatographic partitioning of H2S and CO2 for geological storage of acid gas or impure CO2.
Study and Application of Gelled Foam for In-Depth Water Shutoff in a Fractured Oil Reservoir
Authors: Qing Y. , Yefei W. , Wei Z. , Ziyuan Q. , Fulin Z.
Published: June 2010

A gelled foam is comprised of water, a foaming agent (surfactant), a foaming stabilizer (polymer) and a cross-linking agent. This system with gel as the outer phase is more stable than conventional foam that uses water as the outer phase. Therefore, the gelled foam system prolongs the effective period of water shutoff. By using the Ross Foamer Device to determine its foaming and stability characters, we verify that the best foaming agent is 0.3% YG240; the stable foam agent is 0.2- 0.4% HPAM; the cross-linking agent is 0.09% sodium dichromate and 0.16% sodium sulphite and nitrogen. On the basis of bench-scale evaluations of characters on gelation time and water shutoff efficiency, the pilot test is performed on Well H1340 in the Huoshaoshan fractured reservoir. The workover program includes washing the larger fissures using a highly efficient oil displacement agent, injecting gelled foaming agent, over-displacing fluids, nitrogen and water, then shutting in the well for hardening. Field tests show that good blocking efficiency is gained in the well with a water cut decrease of 20 - 50% and oil production increase of 3.7 - 11.0 m3/day.

Introduction

At present, most oil fields in china are in a high water cut period; injection water and edge water usually breakthrough into oil wells along high permeability zones, causing oil well productivity to decline and development results of waterflooding to get worse. As conventional water shutoff techniques such as mechanical shutoff and chemical shutoff in high permeability zones associating with limited shutoff diameters and depth, the plugging effects decreased rapidly and oil recovery from waterflooding has been greatly affected. In recent years, field tests of profile control with foam have been developed, yet high permeability zones can not be plugged effectively because of a short half life and the limited blocking radius of foam agents. Thus, it is necessary to study the techniques of gelled foam for in-depth water shutoff.
The Velocity and Shape of Convected Elongated Liquid Drops in Vertical Narrow Gaps
Authors: Shad S. , Salarieh M. , Maini B.B. , Gates I.D.
Published: June 2010

The motion and shape of a liquid drop through another continuous liquid phase (conveying phase) in a vertical Hele-Shaw cell with two different apertures were investigated experimentally. Two different liquid/liquid systems were tested. In all cases, the continuous phase was more viscous and wetted the bounding walls. In the capillarity-dominated region, the irregular shape of the discontinuous phase changed with time and distance, with much lower velocity than that of the conveying phase. In contrast to gas/liquid systems, the velocity of these stabilized, elongated drops was 2.5 to almost 5 times higher than that of conveying liquid. Despite the similarities between flow in vertical and horizontal Hele-Shaw cells, the velocity of droplets in a vertical fracture is different from that of a horizontal fracture. A new correlation is derived from dimensionless analysis and the experimental data to predict the elongated drop velocity as a function of the dimensionless parameters governing the system.

Introduction

Two-phase flow in micro-fractures is fundamental to many different fields of advanced science and technology, such as chemical process engineering, bioengineering, medical and genetic engineering, as well as petroleum engineering. For instance, understanding the flow of two-phase fluids in near-parallel gaps through fractured rocks has a significant effect on design of different recovery methods for naturally fractured reservoir.

The flow pattern of two-phase immiscible flow in a fracture depends on the flow rates of the phases, the geometry, aperture, roughness of the fracture, the flow properties of the phases and interfacial tension between the phases. The flow patterns in a fracture are different from that in macro-sized rectangular ducts or pipes because of the small aperture, which can enhance capillary effects. The flow structure in the fracture affects the flow and transport through the surrounding porous matrix blocks. The slug flow pattern in a fracture, which occurs over a wide range of parameters, is frequently encountered in oil-wet fractured reservoirs during the immiscible displacement of viscous oil. It also occurs in natural gas reservoirs during displacement of water during gas production.
CO2 Flooding Potential in West-Central Alberta: Generalized BusinessCase of a Medicine River/Gilby Area Mature Waterflooded Reservoir
Authors: Singhal Ashok K.
Published: June 2010

There are several maturing waterfloods in the Medicine River/Gilby region of West-Central Alberta which are operating at high reservoir pressures, and are suitable candidates for enhanced oil recovery (EOR) by CO2 flooding. Potential CO2 supplies also exist in the region from various petrochemical, as well as sour gas and solution gas processing plants. A prototype reservoir was selected for a detailed "business case" study. CO2 flooding and geological storage were seen to be feasible in the prototype reservoir based on geological/ reservoir reviews, laboratory testing and reservoir simulation.

Economic parameters (payout periods for the investment, rates of return) on risk-weighted basis were moderate in light of front-end capital requirements for extraction, recycle and transportation facilities. The situation would change for the better if regional infrastructure for CO2 capture, extraction and transport is developed. This, in turn, is dependent upon adequate assured demand. On the other hand, demand won't develop unless there is appropriate infrastructure in-place. Fragmented ownership of the resource and of CO2-rich waste gas streams, as well as inertia favouring status quo, are some of the other challenges.

We present here a generalized "business case" for illustrating some of the issues of CO2-EOR implementation.

Introduction

CO2-EOR is receiving increasing attention mainly because of the following emerging trends:Increasing awareness of potential reserves addition by CO2 flooding in mature sedimentary basins such as the Western Canadian Sedimentary Basin (WCSB), based on performance of Weyburn and Joffre Viking CO2 flooding projects in WCSB, and also in various oil fields of West Texas Permian Basin.Growing recognition of the importance of Carbon Capture and Storage (CCS) and anticipated incentives for CCS projects in value-added mode such as EOR.Consensus that the main barrier to widespread implementation of CO2-EOR in Alberta is lack of supply and transportation infrastructure for CO2.
Cyclic Stiffness Degradation in Nonlinear Jackup Dynamics
Authors: Dean E.T.R.. T.R. , Metters R..
Published: June 2010

SNAME (2002) gives equations to describe degradation of foundation stiffness for jackup spudcans, depending on the size of a load cycle within a yield envelope. Using these and other proposals, this paper develops a simplified dynamic analysis of jackup cyclic response. Under static conditions, a lower-bound collapse load for a pinned foundation can be larger than for an encastré assumption. Under dynamic conditions, important nonlinearity because of stiffness degradation is confirmed. Chaotic dynamic responses may be possible.
Potential Benefits of Data Integration for Pipeline Integrity Management Programs
Authors: Fehr D.
Published: June 2010

Pipeline integrity management programs are a requirement under Annex N of CSA Z662.07. Annex N requires that data from many sources and details be collected, integrated and analyzed on a continuous basis. The stated goal is to provide guidance for developing, documenting and implementing pipeline integrity management programs, which provide safe, environmentally responsible and reliable service(1). If executed properly, there should be improved pipeline integrity with measurable improvements and benefits. An important step in reaching this goal is risk assessment, which requires continuous data input to maintain valid integrity assessments. This dynamic process of data collection and integration enables continuous analysis and potentially leads to a more proactive integrity management system.

The biggest problem for most operating companies in creating a dynamic and proactive integrity management program (IMP), compliant with Annex N, is in handling the significant data issues. Indeed, the data collection, integration and analysis are the most daunting tasks of the program. A software solution that accepts data from the many activities involved in the lifecycle of a pipeline system would be potentially beneficial. Application of integrated software tools in the oil and gas industry will result in improved integrity management, greater confidence in our pipeline infrastructure and economic benefits.

We will review some of the data requirements of Annex N of CSA Z662.07 and identify the components of the program that may differ from your existing management plan. The nature and detail of data to be managed will be presented. Finally, we will provide an example of the role that software tools can play to assist in meeting the requirements of this challenging regulatory initiative.
Optimization of Large Gas Pipeline Network--A Case Study in China
Authors: Jin Lu , Wojtanowicz Andrew K.
Published: June 2010

In China, annual natural gas consumption is over 67 billion cubic meters with an expected growth rate of 10% per year. Most of the gas is transported from well heads to markets over cross-country gas networks, which requires construction of the West to East Gas Network--one of the largest gas networks in the world. Presently, the network is comprised of four large-diameter pipelines and will include most major gas pipelines in China in the future. The network distributes approximately 30 x 109 m3 gas per year, of which 3% to 5% is burned to power the gas transportation. At current gas prices, gas transportation costs are roughly 350 million per year, which is a considerable cost that could be reduced by improvements in network design and operation.

This paper reports on a study aimed at optimizing the network to minimize its energy consumption and cost. The large size and complex geometry of the network required breaking the study down into simple components, optimizing operation of the components locally, re-combining the optimized components into the network and optimizing the network globally. This four-step approach employed four different optimization methods, penalty function method, pattern search, enumeration and non-sequential dynamic programming, to solve the problem. The results show that cost savings, because of global optimization, are reduced with increased throughput. For example, increasing the gas rate from 67 - 90 million m3/d would reduce operational cost savings because of optimization from 23% - 1.15%. Moreover, the study shows that if the compressors were fully loaded at their maximum rating, the optimized operation would approach the one being presently practiced. Thus, the optimization is effective and much needed when the system does not work at its maximum capacity, a typical case in the present operations of Chinese gas networks.
Estimation of Steam Chamber Extent Using 4D Seismic
Authors: Tanaka Motonao , Endo Kenji , Onozuka Shigenobu
Published: June 2010

The Steam-Assisted Gravity Drainage (SAGD) process has been successfully implemented to produce ultra-viscous bitumen from the Athabasca oil sands in the province of Alberta. In the Hangingstone area, 15 pairs of SAGD wells had been drilled in the reservoir by 2006, each a maximum of 30 m in thickness and approximately 300 m in depth. The production reached an average of 8,000 BOPD in recent years. The reservoir is geologically characterized as a stacked incised valley with fills in fluvial to upper-estuarine channels. Thin mudstone layers and abrupt changes in facies caused by sedimentary deposits present complexities and difficulties for SAGD implementation.

A 3D seismic survey was conducted in 2002 to obtain a clear view of geology that was fully utilized for planning additional wells. In order to evaluate SAGD efficiency and performance, a time-lapse 3D seismic survey was carried out in 2006. In this paper, P-wave velocity (Vp) maps, transformed from the seismic travel-time maps, were interpreted with a new methodology for evaluating the areal extent of the steam chamber zone created by the SAGD process. In the previous experimental study of seismic velocity measurements with oil sands cores, Vp was found to steeply drop with an increase in temperature and to gently decrease with an increase in pore-pressure.

Based on the experimental results, a petrophysical model was formulated to express Vp as a function of temperature, pressure and water saturation. The high-pressure and high-temperature zone of the SAGD process should generate differences between the first (2002) and second (2006) Vp maps from which we can estimate the area of the reduced bitumen viscosity with a temperature increase. As effects of pressure are probably more areally extensive than effects of temperature, these two effects on the Vp maps need to be segregated. As a new method, a scaling factor for the Vp reduction was first estimated to adjust the laboratory-scale and field-scale. We then calculated a distribution of Vp reduction corresponding to steam chamber conditions in order to decouple composite effects of temperature and pressure, based on the petrophysical model. Distinguishing the high-temperature and high pore-pressure zone from the low-temperature and high pore-pressure zone, we could determine a steam chamber distribution.

The bitumen volume in the steam chamber zone was estimated and compared with the actual production. The methodology, interpretation procedures and results obtained are presented in detail.
An Analytical Model for Water Coning Control Installation in Reservoir With Bottomwater
Authors: Jin Lu , Wojtanowicz Andrew K. , Hughes Richard G.
Published: June 2010

Water coning is a serious problem in maturing reservoirs with bottomwater drive where depleted oil strata overlays sizable water zones. The resulting high values of water cut and minimal oil rate lead to early shutdowns of the wells without sufficient recovery of hydrocarbons in place. For many years, reservoir engineers have looked for effective ways to control water coning, but only a few successful oilfield examples have been reported. Usually, in the presence of bottomwater, wells are completed in the upper section of the pay zone and produce oil below the critical rate in order to prevent or delay water coning. Typically, however, the critical rate is too low to be economical so that high water cut becomes inevitable.

Downhole water sink (DWS) technology, a relatively new and effective method to control water coning, has been increasingly considered by engineers worldwide. Theoretical calculations and field practice have shown that DWS can improve oil production rate, reduce water cut and increase the oil productivity index of a well. However, the technique requires draining and lifting large amounts of water from the aquifer, which increases the cost of production. In order to solve the DWS water lifting problem, a new water coning control method called downhole water loop (DWL) installation has been developed. It has the same advantages as the DWS technique, but it does not need to lift water to the surface.

This paper addresses the feasibility of DWL installation and analytically examines the mechanism of producing water-free oil from the DWL of bottomwater drive reservoirs. The DWL feasibility is tested with a simple analytical model derived in this study. Also, a good match is obtained when comparing the model-calculated data to real production data.
Modeling of Tubing Pickling in Conjunction With Acidizing Treatments
Authors: Al-Mutairi Saleh H. , Hill A. Daniel , Nasr-El-Din Hisham A.
Published: June 2010

Pickling well tubulars to prevent pumping unwanted materials into the formation is an issue that should be decided on an individual-job basis. Acid pickling of tubing is a process of flow in a tube or an annulus with heterogeneous reactions occurring at the wall of the tube. The reacting solid species at the wall are primarily mill scale and other types of inorganic scale. The fluids injected for pickling are usually strong acid solutions [hydrochloric acid (HCl)] but also may include surfactants, organic solvents, and gelled solutions to aid in lifting solids from the wellbore. Thus, the process is a complex one involving several reactions and perhaps multiple stages of fluids.

Tubing pickling is an essential part of well-stimulation treatments if the main acid is to be bullheaded. Standard design parameters for a pickle treatment depend on experience and personal judgment. It appears that the standard pickle-treatment design is overestimating the required volume of pickling acid. Field data indicated that excessive acid volumes were used for tubing pickling because large returns of unreacted (live) acid were recovered at the surface. Careful analysis of flowback samples obtained from several deep gas wells showed that only a fraction of the acid was consumed by mill scale and other tubing contaminants.

In this paper, proposed mechanisms are presented to explain the behavior of acid contact with the tubing and a mathematical model is developed to predict acid consumption and dissolution of tubular contaminants. The model applies to the bullheading case where the acid is pumped down the tubing and then flowed back to the surface. The model considers the reaction of acid with mill scale (Fe3O4). The equations formulated are solved numerically to predict the concentrations of major chemical species in the well flowback samples.

Such a model is extremely valuable in optimizing future pickling treatments. The acid volume needed for pickling operations can be reduced significantly, and other improvements can be made without extensive and costly field testing. Finally, recommendations are given to design acid-pickling treatments better.
Is the Internet Bad News? The Online News Era and the Market for High-Quality News
Authors: Frijters Paul , Velamuri Malathi
Published: June 2010

We review and model the impact of the internet on the production and uptake of high-quality news. Our review of trends in the market for news suggests three stylized facts: i) particular quality news markets are dominated by merely a few providers, ii) demand for quality news appears stable, but provision of news has become specialized; mainstream news is decoupled from quality news, and iii) the dominant business model of internet news mirrors that of radio, television, and newspapers in that costs of news production are recouped via advertising. We build a stylized model that rationalizes these facts. Our model captures three conflicting effects: (1) economies of scale in the production of news lead to monopolies on particular markets, (2) easy access to information on the internet makes it cheaper to provide high-quality news and to disseminate it via the web, which increases the production of such news; and (3) the existence of bloggers and news aggregators who recycle the stories of news-providers reduces the effective property rights of high-quality news producers, thus forcing the business model of the internet to be advertising-based. For the most likely cases, our model would imply that the internet does not constitute bad news for the provision and uptake of quality news.
Ultrasound-Assisted Extraction in Different Solvents for Phytochemical Study of Canna indica
Authors: Vankar Padma S , Srivastava Jyoti
Published: June 2010

Red flowers of Canna indica (Family Cannacece) were extracted in Sonicator with different solvents for the estimation of polyphenols and flavonoids using fresh as well as dry flowers. Antioxidant capacities of L- Ascorbic acid, trolox, pyrogallol and Canna flower extracts were also evaluated based on its ability to scavenge the DPPH radical, results obtained were compared with those of TEAC assay. A good correlation was observed between the two methods. The results showed that acetone extract of fresh flowers contained the highest amount of antioxidant activity 78.33 %, 89.7 mg GAE / g and 51.45 ?MT / g although the yield of the extract in the methanol was highest (34 g / 100 g). Total phenol and flavonoids content (0.96 mg GAE / 100 g) (19.89 mg QE / 100 g) were also evaluated for these extract. This is the first report on the phytochemicals and antioxidant activity from Canna indica flowers particularly for its radical scavenging activity and can be a good source of food additives.
‘A Person is a Person Because of Others’: Challenges to Meanings of Discipline in South African and UK Schools
Authors: McCluskey Gillean , Lephalala Mirriam
Published: June 2010

In this article the authors consider current understandings of discipline in schools in the United Kingdom and South Africa. The concern is with exploring the discipline/punishment/power nexus in education in both countries; with how reductionist versions of discipline as authoritarianism interweave with views about the aims and perceived need for punishment in schools, and how this is driven by perceptions of a need to maintain control or power over young people, often viewed as a ‘generation of suspects’. The authors argue that a restorative approach can be used to build more inclusive school communities where staff and students negotiate new meanings of discipline and power. Some of the key challenges associated with a restorative approach are then explored in detail and the notion of ubuntu – ‘A person is a person because of others' – strongly associated with the new South Africa and its reassertion of traditional principles and values, is suggested as a useful compass for future development in both countries. In very different contexts, but facing many of the same challenges, the authors ask: What can the United Kingdom learn from South Africa and what can South Africa learn from the United Kingdom?
‘What Part of Me Do I Leave Out?’: In Pursuit of Decolonising Practice
Authors: Lavia Jennifer , Sikes Pat
Published: June 2010

This article seeks to foreground the realities and lived experiences of academics who choose to work in non-traditional settings and in non-traditional ways. In doing so, the authors provide narratives to illuminate how centre/periphery encounters are played out as a politics of recognition. The authors provide a critical account of how working on the University of Sheffield's Caribbean Programme has confronted them as subaltern yet organic intellectuals with the complexities and pervasiveness of history, politics and culture where centre/periphery relations require interrogation. Through their narratives the authors seek to privilege (a) the creative, dialogic and discursive spaces in which they work; (b) the centrality of the philosophical, methodological and pedagogical opportunities these spaces provide; and (c) the strategic intervention of critical intellectuals in their work within the academy. The authors highlight sites of contestation in implementing the university's civic mission in respect of international communities. Finally, the authors offer in their interpretations of these transnational experiences an understanding of how research practice can embrace a decolonising agenda.
Flexing Academic Identities: Speaking Truth to Power
Authors: Pirrie Anne , Adamson Kevin , Humes Walter
Published: June 2010

This article is intended as a contribution to the debate on the changing landscape of higher education in the United Kingdom. It challenges the notion that the spread of bureaucratic rationality and the rise of corporate culture have invariably resulted in a loss of meaning in academic life. Drawing upon the work of Onora O'Neill, Max Weber and Jürgen Habermas, the article argues for a more measured response to calls for greater accountability in higher education. The function of university mission groups is also examined, particularly in respect of their role in discursively producing notions of superiority and inferiority in the sector. The authors suggest that it is as much the machinations of influential university mission groups as the ‘iron cage’ of societal rationalisation that have brought about a perceived loss of freedom in academic life.
Using Qualitative Data Analysis Software in a Social Constructionist Study of Entrepreneurship
Authors: Kikooma Julius F.
Published: June 2010

Discussions of the use of computer‐assisted qualitative data analysis software (CAQDAS) in social science research studies are still few and isolated. In fact, much of the literature takes an uncritical approach to CAQDAS programs based on unrealistic expectations of the software as a methodology in and of itself. This has significant implications for learning and teaching qualitative data analysis software and the way it is used in research. The study on which this article is based combined formal narrative analysis, thematic coding, and deconstruction techniques to analyse the data using a dedicated qualitative data analysis software NVivo. A discussion is given of how the qualitative analysis software was used in a social constructionist study, particularly outlining how it fitted with the methodological perspective adopted, and where, why and in what way rigour fitted with the underpinning epistemological position. Thus, this article illuminates how rigour can be integrated with relevance with the aid of the power and possibilities that qualitative research software possesses. In addition, an attempt is made to demonstrate how the use of CAQDAS enhances the validity of a qualitative project.
Silicone Resin Applications for Ceramic Precursors and Composites
Authors: Narisawa Masaki
Published: June 2010

This article reviews the applications of silicone resins as ceramic precursors. The historical background of silicone synthesis chemistry is introduced to explain the production costs and supply availability of various silicones. Thermal degradation processes of silicones are classified in terms of the main chain structure and cyclic oligomer expulsion process, which determine the resulting ceramic yield and the chemical composition. The high temperature decomposition of Si-O-C beyond 1,400 °C in an inert atmosphere and formation of a protective silica layer on material surfaces beyond 1,200 °C in an oxidative atmosphere are discussed from the viewpoints of the wide chemical composition of the Si-O-C materials. Applications of the resins for binding agents, as starting materials for porous ceramics, matrix sources with impregnation, fiber spinning and ceramic adhesions are introduced. The recent development of the process of filler or cross-linking agent additions to resin compounds is also introduced. Such resin compounds are useful for obtaining thick coatings, MEMS parts and bulk ceramics, which are difficult to obtain by pyrolysis of simple organometallic precursors without additives.
Non-Steroidal Anti-Inflammatory Drugs in Alzheimer's Disease and Parkinson's Disease: Reconsidering the Role of Neuroinflammation
Authors: Moore Amy H. , Bigbee Matthew J. , Boynton Grace E. , Wakeham Colin M. , Rosenheim Hilary M. , Staral Christopher J. , Morrissey James L. , Hund Amanda K.
Published: June 2010

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases with age as the greatest risk factor. As the general population experiences extended life span, preparation for the prevention and treatment of these and other age-associated neurological diseases are warranted. Since epidemiological studies suggested that non-steroidal anti-inflammatory drug (NSAID) use decreased risk for AD and PD, increasing attention has been devoted to understanding the costs and benefits of the innate neuroinflammatory response to functional recovery following pathology onset. This review will provide a general overview on the role of neuroinflammation in these neurodegenerative diseases and an update on NSAID treatment in recent experimental animal models, epidemiological analyses, and clinical trials.
Studies of Scattering, Reflectivity, and Transmitivity in WBAN Channel: Feasibility of Using UWB
Authors: Kabir Md. Humaun , Ashrafuzzaman Kazi , Chowdhury M. Sanaullah , Kwak Kyung Sup
Published: June 2010

The Wireless Personal Area Network (WPAN) is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN) used for health monitoring. On the other hand, Ultra-Wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB.
Profile of Indian Patients with Juvenile Onset Chronic Inflammatory Joint Disease Using the ILAR Classification Criteria for JIA: A Community-based Cohort Study
Authors: KUNJIR VINAYA , VENUGOPALAN ANURADHA , CHOPRA ARVIND
Published: June 2010

Objective.

To assess the current International League of Associations for Rheumatology (ILAR) classification criteria (Edmonton, 2001) for juvenile idiopathic arthritis (JIA) in Indian patients.

Methods.

Out of 441 children, 330 with chronic joint pains were diagnosed with juvenile onset chronic inflammatory arthritis and followed in an observational cohort. Our study was carried out from 1994 to 2006 in a community rheumatology clinic. Emphasis was placed on obtaining data required by the ILAR system. Of the original group, 235 children were eventually classified as having JIA; 108 were examined during the first year of illness.

Results.

We assigned 224 children (95%) to discrete JIA categories: enthesitis-related arthritis (ERA; 36%), oligoarthritis (OLA-persistent; 17%), polyarthritis rheumatoid factor (RF)-negative (17%), polyarthritis RF-positive (12%), systemic arthritis (8%), OLA-extended (4%), and psoriatic arthritis (1%). The remaining 11 children (5%) were classified with undifferentiated arthritis (mostly an overlap due to seropositive RF and/or HLA-B27). The prevalence of ERA (89% HLA-B27-positive) and seropositive RF was unexpectedly high. Although agreement (κ > 0.79) with the American College of Rheumatology criteria and the European Spondylarthropathy Study Group criteria was good to excellent, the ILAR system was found to be more comprehensive and clinically homogeneous. However, some problems appear unique in our scenario.

Conclusion.

A wide-spectrum phenotype of JIA is demonstrated by an Indian cohort. Although useful, RF and HLA-B27 in this population proved problematic to the ILAR classification.
Renal Transplant in Wegener’s Granulomatosis Compared to Microscopic Polyangiitis
Authors: GEETHA DUVURU , HAAS MARK , KRAUS EDWARD S. , RABB HAMID , SEO PHILIP
Published: June 2010

Objective.

Antineutrophil cytoplasmic antibody-associated vasculitis is an important cause of endstage renal disease. Our aim was to investigate how the underlying vasculitis diagnosis may influence outcomes following renal transplant.

Methods.

We undertook a retrospective cohort study of patients who underwent renal transplant at the Johns Hopkins Hospital between 1999 and 2008.

Results.

Detailed followup data were available for 11 patients with Wegener’s granulomatosis (WG) and 6 with microscopic polyangiitis (MPA), representing 799 patient-months of observation. Patients with WG remained on hemodialysis longer (and may have had slightly worse renal outcomes following transplant) than patients with MPA. Four patients with WG experienced adverse events following renal transplant: 2 experienced rejection and 2 vasculitis flare. Among the patients with MPA, there was 1 episode of rejection and no vasculitis flare.

Conclusion.

Whether outcomes following renal transplant may be influenced by the underlying diagnosis of vasculitis merits further study.
Cross-sectional and Longitudinal Evaluation of Bone Mass in Children and Young Adults with Juvenile Idiopathic Arthritis: The Role of Bone Mass Determinants in a Large Cohort of Patients
Authors: STAGI STEFANO , MASI LAURA , CAPANNINI SERENA , CIMAZ ROLANDO , TONINI GIULIA , MATUCCI-CERINIC MARCO , de MARTINO MAURIZIO , FALCINI FERNANDA
Published: June 2010

Objective.

To assess the prevalence of reduced spine bone mineral apparent density (BMAD), and to identify the main predictors of reduced spine BMAD in a cross-sectional and longitudinal evaluation of the same large cohort of patients with juvenile idiopathic arthritis (JIA). There are few prospective data on bone mass evaluation in a large number of patients with JIA, and with enthesitis-related arthritis onset.

Methods.

Two hundred nineteen patients with JIA (median age 8.7 yrs, range 6.1–13.1 yrs; 104 oligoarticular JIA, 61 polyarticular, 20 systemic, and 34 enthesitis-related arthritis onset) were retrospectively evaluated. A dual-energy x-ray absorptiometry (DEXA) scan at the lumbar spine was performed in all subjects. Of these, 89 consecutive patients were followed up randomly and longitudinally with a second and a third DEXA evaluation. The data obtained were compared with 80 age-matched and sex-matched healthy subjects.

Results.

At the first DEXA, patients with JIA showed a reduced spine BMAD standard deviation score (SDS) in comparison to controls (p < 0.001). These results were confirmed when the subjects were divided into JIA subtypes (p < 0.005) with the exception of enthesitis-related arthritis onset. Spine BMAD SDS significantly correlated with JIA onset type (p < 0.01), age at JIA onset (p < 0.005), and flares (p = 0.008). The longitudinal evaluation showed that spine BMAD SDS did not significantly improve at the followup in comparison to controls, in all subsets with JIA except for systemic onset (p < 0.05). Spine BMAD correlated with sex (p < 0.01), systemic corticosteroid exposure (p < 0.01), the number of intraarticular corticosteroid injections (p < 0.01), the interval from last steroid injection (p < 0.05), erythrocyte sedimentation rate (p < 0.005), and C-reactive protein levels (p < 0.005).

Conclusion.

Patients with JIA have a low bone mass and, after a first increase due to therapy, do not reach a healthy condition over time despite our current more effective drugs. These patients have a high risk of osteoporosis in early adulthood. To reduce the risk and improve the bone mass, close monitoring of bone mineral density, better control of disease activity, physical activity, and intake of calcium and vitamin D are recommended. In patients with osteoporosis, therapeutic approaches including bisphosphonates should be considered.
Increased Expression of Phospholipid Scramblase 1 in Monocytes from Patients with Systemic Lupus Erythematosus
Authors: SUZUKI ERIKO , AMENGUAL OLGA , ATSUMI TATSUYA , OKU KENJI , HASHIMOTO TOKO , KATAOKA HIROSHI , HORITA TETSUYA , YASUDA SHINSUKE , IEKO MASAHIRO , FUKUSHIMA KAZUAKI , KOIKE TAKAO
Published: June 2010

Objective.

A high incidence of thromboembolic events has been reported in patients with systemic lupus erythematosus (SLE). Phosphatidylserine (PS) is normally sequestered in the inner leaflet of cell membranes. Externalization of PS during cell activation is mediated by phospholipid scramblase 1 (PLSCR1) and has a central role in promoting blood coagulation. We investigated the underlying pathogenic status of thrombophilia in SLE by analyzing PLSCR1 expression on monocytes from patients with SLE.

Methods.

Sixty patients with SLE were evaluated. Twenty-three patients had antiphospholipid syndrome (APS/SLE). Plasma D-dimer levels were measured as a marker of fibrin turnover. The cDNA encoding human PLSCR1 was cloned from the total RNA extract from monocytes, and independent clones were sequenced. PLSCR1 mRNA expression in CD14+ cells was determined by real-time polymerase chain reaction. PS exposure on CD14+ cell surface was analyzed by flow cytometry.

Results.

Elevated D-dimer levels were found in plasma from SLE patients. Three splice variants of PLSCR1 mRNA were identified in all subjects, and levels of full-length PLSCR1 mRNA were significantly increased in SLE compared to healthy controls (2.9 ± 1.5 vs 1.3 ± 0.4, respectively; p < 0.0001). Flow-cytometry analysis showed relative enhancement of PS exposure in the surface of CD14+ cells in SLE patients compared to healthy controls.

Conclusion.

Novel PLSCR1 splice variants were identified. Monocytes in SLE patients had enhanced PLSCR1 mRNA expression, as well as increased fibrin turnover and cell-surface PS exposure, indicating that PLSCR1 may, in part, contribute to the prothrombotic tendency in SLE.
La gestion du risque en France : contre ou avec le territoire ?
Authors: Meschinet de Richemond Nancy , Reghezza Magali
Published: June 2010

Le risque naturel est inhérent au système territorial. Pourtant, malgré l’affirmation d’une nécessaire gestion territorialisée du risque, l’analyse des dispositifs actuels montre une séparation entre risque et territoire. L’étude d’exemples passés souligne que cette approche dichotomique n’a pas toujours été la règle. Dans le Roussillon, au XVIII e siècle, les communautés rurales vivaient avec le risque. Elles géraient un territoire et non un risque sur un territoire. Pour expliquer cette évolution, il faut envisager une évolution des systèmes de valeur et des représentations, qui touchent tant à la façon d’envisager le risque qu’aux rapports de forces entre les acteurs et à la relation au pouvoir.
Que faire du siècle de Louis XIV ?
Authors: Zékian Stéphane
Published: June 2010

Cet article étudie la réception du Siècle de Louis XIV de Voltaire sous le premier Empire et au début de la Restauration. On montre en particulier que cet ouvrage force les publicistes et critiques du temps à un curieux échange des rôles : d’un côté, les ennemis du philosophe en font leur référence favorite ; de l’autre, ses disciples prennent leurs distances avec un texte dont l’héritage paraît trop délicat à endosser. On illustre les principaux aspects de ce renversement, dont on essaie également d’analyser les raisons et de mesurer la portée.