bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive analysis of a straw-fired power plant in Vojvodina
Authors: Urosevic Dragan , Gvozdenac-Urosevic Branka
Published: April 2012

In recent years, renewable energy sources have played an increasingly
important role in potential energy production. The integration of renewable
energy technologies into existing national energy system has therefore
become a major challenge for many countries. Due to the importance of this
matter, this paper deals with the comprehensive analysis for implementation
of a power plant on biomass (straw). The analysis is conducted regarding
several key indicators: availability of biomass, regulation, reduction of
greenhouse gas emissions, location, land use, electricity price and social
impacts. The analysis also includes favorable price for electricity produced
from biomass relevant to national feed in tariffs. In order to demonstrate
all above mentioned indicators, the region in Serbia (Province of Vojvodina)
with significant potential in biomass, especially in straw, is selected. The
results of the analysis are validated trough environmental and social
aspects. Special attention is given to identifying risks for this
application.
Biomass gasification with CHP production: A review of state of the art technology and near future perspectives
Authors: Jankes Goran , Trninic Marta , Stamenic Mirjana , Simonovic Tomislav , Tanasic Nikola , Labus Jerko
Published: April 2012

This paper is a review of the state of the art of biomass gasification and
the future of using biomass in Serbia and it presents researches within the
project ?The Development of a CHP Plant with Biomass Gasification?. The
concept of downdraft demonstration unit coupled with gas engine is adopted.
Downdraft fixed-bed gasification is generally favored for CHP, owing to the
simple and reliable gasifiers and low content of tar and dust in produced
gas. The composition and quantity of gas and the amount of air are defined by
modeling biomass residues gasification process. The gas (290-400m3/h for 0.5-
0.7MW biomass input) obtained by gasification at 800oC with air at
atmospheric pressure contains 14% H2, 27% CO, 9% CO2, 2% CH4, and 48% N2, and
its net heating value is 4.8-6 MJ/Nm3. The expected gasifier efficiency is up
to 80%. The review of the work on biomass gasification has shown that the
development of technology has reached the mature stage. There are CHP plants
with biomass gasification operating as demonstration plants and several
gasification demonstration units are successfully oriented to biofuel
production. No attempt has been made here to address the economic feasibility
of the system. Economics will be the part of a later work as firmer data are
acquired.
Potentials and market prospects of wind energy in Vojvodina
Authors: Katic Vladimir , Dumnic Boris , Katic Nenad , Milicevic Dragan , Grabic Stevan
Published: April 2012

The paper presents an overview of the wind energy potentials, technologies
and market prospects in the Autonomous Province of Vojvodina, the region of
Serbia with the most suitable location for exploitation of wind energy. The
main characteristics of the region have been presented regarding wind energy
and electric, road, railway and waterway infrastructure. The wind farm
interconnection with the public grid is explained. The most suitable
locations for the wind farms are presented, with present situation and future
prospects of wind market in Vojvodina.
Audit Quality and Auditor Reputation: Evidence from Japan
Authors: Skinner Douglas J. , Srinivasan Suraj
Published: April 2012

We study events surrounding ChuoAoyama's failed audit of Kanebo, a large Japanese cosmetics company whose management engaged in a massive accounting fraud. ChuoAoyama was PwC's Japanese affiliate and one of Japan's largest audit firms. In May 2006, the Japanese Financial Services Agency (FSA) suspended ChuoAoyama for two months for its role in the Kanebo fraud. This unprecedented action followed a series of events that seriously damaged ChuoAoyama's reputation. We use these events to provide evidence on the importance of auditors' reputation for quality in a setting where litigation plays essentially no role. Around one quarter of ChuoAoyama's clients defected from the firm after its suspension, consistent with the importance of reputation. Larger firms and those with greater growth options were more likely to leave, also consistent with the reputation argument.

Data Availability: All data in the paper are publicly available from the sources described in the text.
Investigation of Friction Mechanisms of Siped Tire Tread Blocks on Snowy and Icy Surfaces
Authors: Ripka S. , Lind H. , Wangenheim M. , Wallaschek J. , Wiese K. , Wies B.
Published: April 2012

REFERENCE: S. Ripka, H. Lind, M. Wangenheim, J. Wallaschek, K. Wiese, and B. Wies “Investigation of Friction Mechanisms of Siped Tire Tread Blocks on Snowy and Icy Surfaces,” Tire Science and Technology, TSTCA, Vol. 40, No. 1, January–March 2012, pp. 1–24.

ABSTRACT: Due to general safety reasons and an increasing individual demand on more traffic safety, winter tires have become more and more important. This evolution results in a rising requirement of the customers concerning the tire performance on the one hand, and the effort of the tire industry to improve the tire traction performance on snow and ice on the other hand. To engineer winter tires in an effective way, the friction influencing factors as well as the contact mechanics should be well known. Normally the design and development of tires is strongly based on vehicle tests, but in modern tire development processes the simulation as well as the experimental investigation of tires and tire components in the lab have become more popular. This strategy plays an especially important role for reducing the time of development cycles but also the development costs. With simulation and experiments in lab, new challenges come up which have to be solved. Lab experiments compete with totally different problems: First of all, the environmental influences like temperature and humidity have to be controlled. Furthermore, the test tracks used inside must be comparable to the proving ground outside, hence the properties of snow and ice have to be investigated in detail. Therefore not only is it very important to understand the formation of snow and ice, but also to find characteristics of both materials which can be identified and measured with mobile measurement devices outside on the test track and inside in the lab. Within this publication a general overview of the tire tread block test method as well as the test rig, which are used for identifying relevant tread block friction mechanisms on snow and ice, will be given. The results of the measurement will be shown and the acting friction phenomena will be explained.
Impact of an injury prevention program on teenagers' knowledge and attitudes: results of the Pense Bem–Caxias do Sul Project
Authors: Falavigna Asdrubal , Teles Alisson Roberto , Velho Maíra Cristina , Medeiros Gregory Saraiva , Canabarro Carolina Travi , de Braga Gustavo Lisbôa , Barazzetti Daniel Ongaratto , Vedana Viviane Maria , Kleber Fabrício Diniz
Published: April 2012

Object

Trauma is the leading cause of mortality and morbidity in children, young people, and working-age adults. Because of the high incidence of intentional and unintentional injuries in young people, it is necessary to implement injury-prevention programs and measure the efficacy of these initiatives. The authors evaluated the effectiveness of an injury-prevention program in high school students in a city in southern Brazil.

Methods

In a randomized controlled study, 1049 high school students were divided into a control group and intervention group. The study was conducted in the following 3 stages: a questionnaire was applied 1 week before the educational intervention (P0), shortly after the intervention (P1), and 5 months later (P3). In the control group, a questionnaire based on the Pense Bem Project was applied at the 3 time stages, without any intervention between the stages.

Results

The postintervention analysis evidenced a slight change in knowledge about unintentional spinal cord and brain injuries. Regarding attitudes, the only significant improvement after the intervention lecture was in the use of helmets, which remained high 5 months later. A substantial number of students only partially agreed with using safety behaviors. The only significant postintervention change was the major agreement to check swimming pool depth before entering the water (P0 89% and P1 97.8%, p < 0.001; P2 92.8%, p = 0.005).

Conclusions

An educational intervention based on a single lecture improved students' knowledge of traumatic brain and spinal cord injuries, but this type of intervention did not modify most attitudes toward injury prevention. Clinical trial registration no.: U1111-1121-0192.
Experience with a gravitational valve in the management of symptomatic overdrainage in children with shunts
Authors: Weinzierl Martin R. , Hans Franz-Josef , Stoffel Michael , Oertel Markus F. , Korinth Marcus C.
Published: April 2012

Object

Symptomatic overdrainage in children with shunt-treated hydrocephalus represents one of the more difficult shunt-related diseases and may require repeated surgery. Gravity-assisted valve design has become a standard device to avoid overdrainage in many European pediatric hydrocephalus centers. However, the use of a gravitational valve for relieving symptoms associated with overdrainage has not yet been addressed. The goal of this study was to evaluate the effectiveness of a gravitational valve in the treatment of symptomatic overdrainage in children with shunts.

Methods

Seventeen children with an adjustable shunt system and symptomatic overdrainage were treated by insertion of a gravitational valve. Clinical and radiological outcome were monitored for a minimum of 12 months after surgery.

Results

Implantation of a gravitational valve resulted in either resolution (n = 12) or improvement (n = 5) of the symptoms. In 1 patient, symptoms remained almost unchanged and the gravitational valve had to be upgraded, resulting in resolution of the symptoms. During follow-up, the pressure setting of the adjustable differential pressure valve had to be changed in 7 patients.

Conclusions

The gravitational valve was effective in improving symptomatic overdrainage in the majority of patients in the present study. Because the ideal pressure setting for a given patient is hard to determine a priori, adjustable valve systems appear to be beneficial.
Marvelous medicine: the untold story of the Wade-Dahl-Till valve
Authors: Sandler Adam L. , Sturrock Donald , Branfield Jane , Abbott Rick , Goodrich James T. , Biswas Arundhati , Daniels Lawrence B. , Flamm Eugene S.
Published: April 2012

On December 5, 1960, 4-month-old Theo Dahl, the only son of best-selling author Roald Dahl (1916–1990), had his skull shattered in a horrific traffic accident. What began as a personal tragedy for the Dahl family would soon evolve into a dogged crusade by Dahl to expand upon preexisting valve technology with the goal of developing a shunt that would not become obstructed. Based upon exclusive access to private archives of the Dahl estate, as well as interviews with those involved, this article tells the intricate tale of one famous father's drive to significantly alter the natural history of pediatric hydrocephalus. Dahl's collaboration with British toymaker Stanley Wade and pioneering pediatric neurosurgeons Joseph Ransohoff, Kenneth Shulman, and Kenneth Till to create the Wade-Dahl-Till (WDT) valve is examined in detail. The ensuing rift between the American and British contingents, the valve's multiple design revisions, and the goal of creating an affordable shunt for children in developing countries are among the issues addressed. The development of the WDT valve marked a significant turning point in the surgical management of pediatric hydrocephalus in general and in shunt valve technology in particular.
Controlled hypotension and blood loss during frontoorbital advancement
Authors: Seruya Mitchel , Oh Albert K. , Rogers Gary F. , Boyajian Michael J. , Myseros John S. , Yaun Amanda L. , Keating Robert F.
Published: April 2012

Object

Controlled hypotension is routinely used during open repair of craniosynostosis to decrease blood loss, although this benefit is unproven. In this study the authors analyzed the longitudinal relationships between intraoperative mean arterial pressure (MAP) and calculated blood loss (CBL) during frontoorbital advancement (FOA) for craniosynostosis.

Methods

The authors reviewed the records of infants with craniosynostosis who had undergone primary FOA between 1997 and 2009. Anesthesia records provided preoperative and serial intraoperative MAP. Interval measures of CBL had been determined during the course of the operation. The longitudinal relationships between MAPmean, MAPchange, and CBLchange were assessed over the same time interval and compared between adjacent time intervals to determine the directionality of associations.

Results

Ninety infants (44 males and 46 females) underwent FOA at a mean age and weight of 10.7 ± 12.9 months and 9.0 ± 7.0 kg, respectively. The average intraoperative MAP was 56.1 ± 4.8 mm Hg, 22.6 ± 12.1% lower than preoperative baseline. A negative correlation was found between CBLchange and MAPmean over the same interval (r = −0.31, p < 0.05), and an inverse relationship was noted between CBLchange of the previous interval and MAPchange of the next interval (r = −0.07, p < 0.05). Finally, there was no significant association between MAPchange of the previous interval and CBLchange of the next interval.

Conclusions

Calculated blood loss demonstrated a negative correlation with MAP during FOA. Directionality testing indicated that MAP did not affect intraoperative blood loss; instead, blood loss drove changes in MAP. Overall, these findings challenge the benefit of controlled hypotension during open craniofacial repair.
Intramedullary spinal neurenteric cyst with fluid-fluid level
Authors: Jhawar Sukhdeep Singh , Mahore Amit , Goel Atul
Published: April 2012

Spinal neurenteric cysts are rare intradural extramedullary lesions of the spine, commonly located in the cervical and thoracic regions. The majority localize ventral to the spinal cord and are associated with other vertebral anomalies. Here, the authors report a rare case of a 3-year-old boy presenting with a 1-week history of meningismus followed by rapid-onset (over a few hours) paraplegia. Magnetic resonance imaging revealed an intramedullary cystic lesion with a fluid-fluid level in the cervicothoracic region of the spinal cord without associated bony or soft tissue abnormalities. To the best of the authors' knowledge, such clinical and radiological presentation of a spinal neurenteric cyst has never been reported. A brief review of the pertinent literature is presented, and the possible pathophysiology of such a presentation is also discussed.
Synthesis and Structure Analysis of 1-(3-Methoxybenzoyl)-3,6-Diphenyl-1,4-Dihydro-1,2,4,5-Tetrazine
Authors: Rao Guo-Wu , Guo Yan-Mei , Li Xiao-Min
Published: April 2012

1-(3-Methoxybenzoyl)-3,6-diphenyl-1,4-dihydro-1,2,4,5-tetrazine was prepared from 3-methoxybenzoyl chloride and 3,6-diphenyl-1,2(or 1,4)-dihydro-1,2,4,5-tetrazine, and its structure was determined by X-ray diffraction. This reaction yields the title compound rather than 1-(3-methoxybenzoyl)-3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine. The central tetrazine ring of the title compound exhibits a boat conformation and therefore, is not homoaromatic.
Synthesis of Novel Chiral Cholic Acid-Based Molecular Tweezers Containing Unsymmetrically Disubstituted Urea Units Using Microwave Irradiation
Authors: Zeng Bitao , Zhao Zhigang , Zhou Lijun , Li Qinghan
Published: April 2012

An efficient procedure has been developed for the synthesis of new chiral cholic acid molecular tweezer artificial receptors by linking an unsymmetrically disubstituted urea to methyl deoxycholate via a carbonate chain using microwave irradiation. The structures of these new receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. Their binding properties were examined by UV-Vis spectra titration. The preliminary results indicate that these molecular tweezers not only recognised anions, but also showed good enantioselectivity for D-amino acid methyl esters.
To Be or Not to Be Socrates: Introduction to the Translation of Félix Guattari's Socrates
Authors: Garcin-Marrou Flore
Published: April 2012

The Fonds Guattari contain a number of unpublished manuscripts catalogued under the title of ‘écrits littéraires’ which include a set of theatrical dialogues. Noting the scope of these titles, as well as their likely models, Guattari's theatrical practices are introduced with reference to the only play that was actually staged, Socrates, courtesy of Enzo Cormann at the Théâtre Ouvert, in Paris, in 1988.
Guattari TV, By Kafka
Authors: Genosko Gary
Published: April 2012

Guattari looked for crossovers between film and television in a posthumously published ‘Project for a Film By Kafka’. His critical comments on television and the mixed reception of television within the Deleuzo-Guattarian literature provide the occasion for an investigation of what Guattari thought television could do for his project. The auteur model best suits his needs in this regard, with the proviso that it is animated by a modernist aesthetic oriented towards the conjuring of a people to come who would join the Kafka assemblage as part of their viewing experience.
Play as an Affective Field for Activating Subjectivity: Notes onThe Machinic Unconscious
Authors: Colman F. J.
Published: April 2012

How often does an interest or pleasure in your life become something that has to be managed, given a hierarchical position amongst other tasks, and thus becomes a chore alongside other chores? When content and possibility are stripped by scheduling and the demands of capitalist required labour mean that free play or time required for speculative and/or creative thought is removed in the interests of deadlines, what happens to the compassionate, generous and intimate functioning of thought and life? This paper considers how Guattari argues that subjectivities are produced and organised by what he describes as machinic assemblages. Machinic assemblages are those aspects of life that operate to regulate the affective powers of life. Guattari's work on activities such as art making, game play, music and performance provides ways to consider the labour of subjectivity outside of work. I ask the reader to consider what the notion and motivation for play signal. Arguing that a singular life at play is the collective event of play, I describe play as a mediatising form for the production of subjectivity. The play field situates and directs the machinic assemblage of subjectivation through its own forms of mediatisation.
… And … and … and … The Transversal Politics of Performative Encounters
Authors: Kanngieser Anja
Published: April 2012

This paper examines Guattari's notion of transversality through a creative and ambiguous form of political intervention, the performative encounter. Drawing from Guattari's work on subject groups, in combination with Deleuze's conjunctive ‘and’, via contemporary theorisations of creative activism and affect, it maps out a movement that destabilises categorical dualisms between activists and non-activists, artists and non-artists. It proposes that transversals such as those enacted by the performative encounter open spaces for the emergence of new subjectivities, relations and worlds. In doing so it critically extends Guattari's conceptualisations of political organisation, group subjectivation and aesthetics into radical political terrains that are antagonistic of the nation-state and capital at the same time as being affirmative of possible present and future conditions.
Culture as Existential Territory: Ecosophic Homelands for the Twenty-first Century
Authors: Watson Janell
Published: April 2012

The mass popular dissent which has marked the early twenty-first century, from al-Qaeda to the Arab Spring to the Occupy movement, can be read as expressions of collective, subjective, existential mutation. This reading is inspired by Félix Guattari, who described the 1979 Iranian revolution, the Polish Solidarity movement and the 1989 Chinese student demonstrations as demands for subjective singularisation. In each of these examples of social discontent, past and present, demands vary widely even within the same movement, spanning economics, lifestyle, religion and politics, and ranging from cries for liberation to conservative returns to ancient tradition. In order to perform a schizoanalysis of such amorphous movements, Guattari developed a four-part ecosophic object, composed of existential Territories, Universes of value, material-energetic Flows and machinic Phyla. Assemblages can be dynamically mapped along these four dimensions. Of crucial importance in the age of extreme deterritorialisation is the existential Territory, which could potentially take the form of a homeland based on poetry or music rather than on ethnicity or even place. Such portable homelands would characterise the dissensual processual post-media era for which Guattari longed.
Photonic Crystal Structure and Coloration of Wing Scales of Butterflies Exhibiting Selective Wavelength Iridescence
Authors: Mika Filip , Matějková-Plšková Jiřina , Jiwajinda Suratwadee , Dechkrong Punyavee , Shiojiri Makoto
Published: April 2012

The coloration of butterflies that exhibit human visible iridescence from violet to green has been elucidated. Highly tilted multilayers of cuticle on the ridges, which were found in the scales of male S. charonda and E. mulciber butterflies, produce a limited-view, selective wavelength iridescence (ultraviolet (UV)~green) as a result of multiple interference between the cuticle-air layers. The iridescence from C. ataxus originates from multilayers in the groove plates between the ridges and ribs. The interference takes place between the top and bottom surfaces of each layer and incoherently between different layers. Consequently, the male with the layers that are ~270 nm thick reflects light of UV~560 nm (green) and the female with the layers that are ~191 nm thick reflects light of UV~400 nm (violet). T. aeacus does not produce the iridescent sheen which T. magellanus does. No iridescent sheen is ascribed to microrib layers, which are perpendicular to the scale plane, so that they cannot reflect any backscattering. The structures of these butterflies would provide us helpful hints to manipulate light in photoelectric devices, such as blue or UV LEDs.
Suffruyabiosides A and B, Two New Monoterpene Diglycosides from Moutan Cortex
Authors: Furuya Rie , Hu Honghai , Zhang Zhenya , Shigemori Hideyuki
Published: April 2012

Two new monoterpene diglycosides, suffruyabiosides A (1) and B (2), and seven known compounds 3–9 were isolated from Moutan Cortex (root cortex of Paeonia suffruticosa Andrews). The structures were elucidated on the basis of 2D NMR spectral data. Suffruyabiosides A (1) and B (2) are rare monoterpene diglycosides, including a cellobiose in the molecules. Salicylpaeoniflorin (4) had a antiproliferation effect similar to paeoniflorin (3) on human lung adenocarcinoma epitherial A549 cells. Galloylpaeoniflorin (8) and salicylpaeoniflorin (4) revealed a more pronounced radical scavenging effect than a-tocopherol (positive control). An increase in the number of phenolic hydroxyl groups produced a more effective radical scavenging effect [8 > mudanpioside E (6) > oxypaeoniflorin (5)]. Comparison of the effects of 4 and 5 showed that o-substitution with a phenolic hydroxyl group was more effective than p-substitution. The results suggest that salicylpaeoniflorin (4) may be useful as a cytotoxic and a radical scavenging agent.
Carbohydrate-auxiliary assisted preparation of enantiopure 1,2-oxazine derivatives and aminopolyols
Authors: Jasiński Marcin , Lentz Dieter , Reissig Hans-Ulrich
Published: April 2012

An approach to enantiopure hydroxylated 2H-1,2-oxazine derivatives is presented utilizing the [3 + 3] cyclisation of lithiated alkoxyallenes and an L-erythrose-derived N-glycosyl nitrone as precursors. This key step proceeded only with moderate diastereoselectivity, but allowed entry into both enantiomeric series of the resulting 3,6-dihydro-2H-1,2-oxazines. Their enol ether double bond was then subjected to a hydroboration followed by an oxidative work-up, and finally the auxiliary was removed. The described three-step procedure enabled the synthesis of enantiopure hydroxylated 1,2-oxazines. Typical examples were treated with samarium diiodide leading to enantiopure acyclic aminopolyols. We also report on our attempts to convert these compounds into enantiopure hydroxylated pyrrolidine derivatives.
3D AutoSysLab Prototype - A Social, Immersive and Mixed Reality Approach for Collaborative Learning Environments
Authors: Schaf Frederico Menine , Paladini Suenoni , Pereira Carlos Eduardo
Published: April 2012

Recent evolutions of social networks, virtual environments, Web technologies and 3D virtual worlds motivate the adoption of new technologies in education, opening successive innovative possibilities. These technologies (or tools) can be employed in distance education scenarios, or can also enhance traditional learning-teaching (blended or hybrid learning scenario). It is known and a wide advocated issue that laboratory practice is essential to technical education, foremost in engineering. In order to develop a feasible implementation to this research area, a prototype was developed, called 3DAutoSysLab, in which a metaverse is used as social collaborative interface, experiments (real or simulated) are linked to virtual objects, learning objects are displayed as interactive medias, and guiding/feedback are supported via an autonomous tutoring system based on user's interaction data mining. This prototype is under test, but preliminary applied results indicate great acceptance and increase of motivation of students.
Comparative Study of Electronics Visualisation Techniques for E-Learning
Authors: Touhafi Abdellah , Braeken An , Verbelen Yannick , Gueuning Francis
Published: April 2012
Online gaming as sociable media
Authors: Thorne Steven L. , Fischer Ingrid
Published: April 2012

Over much of the world, contemporary communicative practices are mediated by a wide range of digital technologies that support speech, image, video, and of course textual literacies. In dialectic tension with the rapid growth in digital information and communication media, Internet information and communication technologies have amplified conventional communicative practices in terms of breadth, impact and speed and have also enabled the emergence of new communicative, cultural and cognitive practices. These practices form dynamic cultures-of-use – that is, communication tools and the human activities they mediate co-evolve (Thorne, 2003). This article begins with a review of contradictory appraisals of digital media. This is followed by a discussion of the social and semiotic contexts comprising the widely played massively multiplayer online game World of Warcraft, with a view toward better understanding its usefulness as a setting for language use and learning. This game environment is explored using three forms of evidence, (1) unsolicited reports from players appearing in player-to-player online discussion forums, (2) elicited descriptions of players' experience provided through questionnaires distributed to Dutch and American gamers, and (3) a formal assessment of the linguistic complexity of high frequency game-presented and player-generated texts. By way of conclusion, we elaborate on the necessity of an "open source epistemology" (Lankshear & Knobel, 2006) and a critical language awareness approach to developing and acknowledging a diversity of communicative practices, all of which are aimed at expanding the goals, and outcomes, of instructed L2 education.
De l'attrait des médias sociaux pour l'apprentissage des langues – Regard sur l'état de l'art
Authors: Zourou Katerina
Published: April 2012

Ce texte dresse l'arrière-plan contextuel et notionnel des articles retenus pour le numéro spécial "Médias sociaux et apprentissage des langues : (r)évolution ?". Il commence par une définition d'un certain nombre de termes qui dominent le discours actuel comme "médias sociaux", "web 2.0", "web social", "sites de réseautage social" et "communautés web 2.0 d'apprentissage des langues". L'objectif n'est pas de "réinventer la roue" en suggérant de nouvelles définitions mais de synthétiser les définitions dominantes et de les confronter à des concepts proches de la littérature du domaine de l'Alao. Sont ensuite discutés trois aspects clés des technologies du web 2.0 (participation de l'utilisateur, ouverture et effets de réseautage). Ces trois caractéristiques étaient, certes, déjà présentes avec les technologies qui ont précédé les médias sociaux, nous examinons donc en quoi elles prennent, ou non, un sens radicalement différent à l'ère des médias sociaux. Un certain nombre de pistes de recherche sont discutées dans la dernière partie du texte.
Development of Optimum Well Control Practices Using Artificial Bayesian Intelligence
Authors: Al-yami Abdullah Saleh , Schubert Jerome
Published: April 2012

Many well control incidents have been analyzed, resulting in the optimumpractices, as outlined in this paper. To the best of the authors' knowledge, there are no systematic guidelines for well control practices. The objective ofthis paper is to propose a set of guidelines for the optimal well controloperations, by integrating current best practices through a decision-makingsystem based on Artificial Bayesian Intelligence. Best well control practicescollected from data, models, and experts' opinions, are integrated into aBayesian Network BN to simulate likely scenarios of its use that will honorefficient practices when dictated by varying operation, kick details, and kick severity.

The proposed decision-making model follows a causal and an uncertainty-basedapproach capable of simulating realistic conditions on the use of well controloperations. For instance, as the user vary the operation, rig and crewcapabilities, kick details (such as slim hole, deviated or horizontal well), the system will show the optimum practices for circulation method.

Well control experts' opinions were considered in building up the model in thispaper. The advantage of the artificial Bayesian intelligence method is that itcan be updated easily when dealing with different opinions. The outcome of thispaper is user-friendly software, where you can easily find the specific subjectof interest, and by the click of a button, get the related information you areseeking.

Introduction

The purpose of development of well control procedure is to prevent catastrophesthat could result from blowouts. The objective of this paper is to propose amodel to serve as a training tool. The development of up to date source ofproper well control practices is a challenging task. Using current methods offlow charts in decision making does not allow enough room for different orchanging well control practices to be included.

The design of optimum well control practises depends mainly on previousexperience and knowledge to successfully complete with a degree of confidence. Effective communication is also an important factor for successful well controloperations. Good coordination is required between the engineer, the servicecompany and the rig foreman. Knowledge transfer in well control operations istherefore fundamental for the optimal design of the job.

Field experiences are required for well control specialists to select optimumpractices. In some instances, well control operation failures can occur becauseof the lack of knowledge or lack of knowledge transfer.

There are different methods that companies have approached to make guidelinesfor their engineers to save on operations cost and time. However, these methodscan not be used by other companies or experts with different opinions or withdifferent field conditions.

Al-Yami et al. (2010) were the first to propose a systematic approach to buildexpert systems that can be used in optimum selection and execution ofsuccessful cementing operations using Artificial Bayesian Intelligence.
Guidelines for Optimum Underbalanced Drilling Practices Using Artificial Bayesian Intelligence
Authors: Al-yami Abdullah Saleh , Schubert Jerome
Published: April 2012

Many underbalanced drilling operations have been analyzed, resulting in theoptimum practices, as outlined in this paper. To the best of the authors'knowledge, there are no systematic guidelines for underbalanced drilling.

The objective of this paper is to propose a set of guidelines for the optimalunderbalanced drilling operations, by integrating current best practicesthrough a decision-making system based on Artificial Bayesian Intelligence. Optimum underbalanced drilling practices collected from data, models, andexperts' opinions, are integrated into a Bayesian Network BN to simulate likelyscenarios of its use that will honor efficient practices when dictated byvarying certain parameters suchas formation pressure and operation. Theproposed decision-making model follows a causal and an uncertainty-basedapproach capable of simulating realistic conditions on the use of underbalanceddrilling operations. For instance, by varying the type of UBD (flow, aerated, etc), operation and formation properties the system will show optimum trippingand connection procedure.

The developed model also acknowledged UBD drilling techniques in differentscenarios such as fractured formations, low permeability and high permeabilityformations. The model also shows optimum solutions to problems related tounderbalance drilling such as well control, completion, equipment associatedwith drilling.

Experts' opinions were considered in building up the model in this paper. Theadvantage of the artificial Bayesian intelligence method is that it can beupdated easily when dealing with different opinions. The outcome of this paperis user-friendly software, where you can easily find the specific subject ofinterest, and by the click of a button, get the related information you areseeking.

Introduction

The design of optimum underbalanced drilling operations depends mainly onprevious experience and knowledge to successfully complete with a degree ofconfidence. Effective communication is also an important factor for successfuloperations. Good coordination is required between the engineer, the servicecompany and the rig foreman. Knowledge transfer in underbalanced drillingoperations is therefore fundamental for the optimal design of the job.

Long field experience is required for underbalanced drilling specialists toselect optimum practices. In some instances, operation failures can occurbecause of the lack of knowledge or lack of knowledge transfer.

There are different methods that companies have approached to make guidelinesfor their engineers to save on operations cost and time. However, these methodscan not be used by other companies or experts with different opinions or withdifferent field conditions.

Al-Yami et al. (2010) were the first to propose a systematic approach to buildexpert systems that can be used in optimum selection and execution ofsuccessful cementing operations using Artificial Bayesian Intelligence.
Accounting for VIV in Wake Induced Motion of Risers in Tandem at High Reynolds Number
Authors: Saint-marcoux Jean-Francois , Blevins Robert D.
Published: April 2012

As production of oil and gas from deepwater and ultra deepwater increases, riser interference becomes critical for engineering design and analysis. Theuse of seafloor space must be optimized and the size of the floating unitsreduced. For example SCR's are closely spaced at the FPU and lay in close rangeat the seafloor. Similarly for decoupled riser systems, jumpers are located atshort distances at the FPU level.

Blevins provided the seminal paper on the forces and stability of a cylinder ina wake. One of the major conclusions of his paper was that accounting for dragas per Huse should be refined to be able to assess the potential instability ofa downstream cylinder in a wake.

To be complete it was necessary to expand the theory to the case of an upstreamcylinder in cross vibration about its steady position. This took more timebecause the wake behind a vibrating cylinder does not follow the classical bellshape curve. Obtaining reliable experimental data to be able to describe it wasdifficult, especially at high Reynolds number (105).

The paper presents experimental data for a wake behind a vibrating (and - forbenchmarking - a fixed) cylinder from 2D downstream to 50D downstream. Arelatively simple extension of the Blevins original theory allows accountingfor the modified shape of the wake.

Role of Interferences in the Design of Deepwater Riser Systems

Deepwater and ultra deepwater developments require a close spacing of therisers and flowlines in order to optimize the seafloor. Examples of suchpractical configurations are:–Decoupled risers (Bundle-HRT and SHR);+interference between the BHRT or SHR risers themselves as they are locatedclose to each other+Turret-moored FPSO's with Bundle Hybrid Riser Towers (Bundle-HRT);interference between the top jumpers that run from the top of the Bundle HRT tothe turret-FPSO+For submerged buoy such as the BSR (Boia de Suporte de Riser - risers supportbuoy), interference between the risers as the spacing governs the length of thebuoy (this applies to SCR's as well as Flexibles)

– Coupled risers (SCR's, Flexibles):–For spread-moored FPSO's; interference between the risers at the FPSO side, as the spacing of the risers is critical. This is because the further away fromthe center of the vessel, the higher is the excitation provided by the pitchand roll of the FPSO

This is also referred to as Wake Induced Motion (WIM). As a generalguideline DNV (2009), recommends analyzing riser interference in the range ofup to 25 diameters downstream. For a typical riser of 0.3m (outer diameter), this corresponds to a 7.5m range, whereas this corresponds to about 60m for aBundle-HRT. Clearly those are ranges of actual engineering applications.

The general case of interference of arrays of risers is simplified in practiceby using strip theory and considering the two closest risers at any given time. Also the time-average hydrodynamic excitation forces are considered.
Experimental Study on Wax Deposition Characteristics of a Waxy Crude Oil Under Single Phase Turbulent Flow Conditions
Authors: Dwivedi Priyank , Sarica Cem , Shang Wei
Published: April 2012

Crude oil, having a paraffin nature, has been studied extensively in thesmall-scale flow loop at Tulsa University Paraffin Deposition Projects (TUPDP). The effects of turbulence/shear and thermal driving force on wax depositioncharacteristics were experimentally studied using a waxy crude oil from theGulf of Mexico. The test matrix consisted of a total of 15 experiments whichinclude 12 short term tests and 3 long term tests. The tests were conductedunder different operating conditions with a wide range of Reynolds numbers from3,700 to 20,500. The shear stress ranged from 5.4 to 53.9 Pa.

It was observed that paraffin deposition is highly dependent on the thermaleffective driving force which is the temperature difference between oil bulkand initial inner pipe wall and also on turbulence effects. The depositthickness obtained using both the pressure drop method and a direct measurementwas found to decrease with increasing shear stress and decreasing thermaldriving force. The wax content showed a gradual increase with an increase inflow rate. For the short term tests, the deposit mass with no entrained oilseemed to increase and then decrease with an increase in initial shear stressand decrease in effective thermal driving force whereas the total deposit masswas found to decrease with an increase in initial shear stress or decrease ineffective thermal driving force.

Introduction

When crude oil flows through the subsea and production pipelines, the oiltemperature drops due to the colder surroundings. It has been observed throughexperiments and postulated in literature that when the bulk temperature of thecrude oil in pipes is higher than the wall temperature, there exists adissolved wax concentration gradient between the bulk oil and the pipe wall. The n-paraffin components are considered to be mainly responsible for waxdeposition (Benallal et al. 2008). When the pipe wall temperature goes belowthe wax appearance temperature (WAT) of the oil, the liquid wax diffusestowards the wall. The liquid wax diffused towards the pipe wall crystallizes on the wall surface orat the interface between the bulk and deposit. The wax deposit may eventuallyblock the pipes. Hence, it is imperative to accurately predict wax depositionunder different operating conditions. The main problems associated with waxdeposition are the increased pressure drop in the pipeline, reducedproductivity and the risk of getting a pig stuck during regular maintenanceoperations.

The current paraffin deposition models can predict wax depositioncharacteristics with high confidence under zero or low shear rate conditionswhile they can grossly over predict and under predict paraffin deposition underturbulent flow or high shear conditions. Understanding of the physics behindparaffin deposition in single phase can help accurately model the behavioraiding in the prediction of paraffin deposition and in deciding the piggingfrequency.
Olympus TLP: PFP Optimization and Blast Mitigation
Authors: Popat Nilesh Rasik , Suardin Jaffee , Howell Steven
Published: April 2012

Shell designed, is building, and will operate Mars B Project Olympus TensionedLeg Platform (TLP) with Drilling and Completion Platform Rig to produce 100MBOPD oil and 100MMSCFD gas. Protecting people and environment is the toppriority for Shell. Initial design assumptions for Passive Fire Protection(PFP) application and blast design to protect people could result in the needfor significantly high weight allowances. Therefore, there is a need to find acomprehensive and structured approach to optimize PFP and blast mitigation todeliver reasonable weight allowances.

This paper demonstrates how, through the use of practical safety assessments, weight allowances for PFP application and blast design can be optimized. Itdescribes how the Mars B Project was able to demonstrate As Low as ReasonablyPracticable (ALARP) risks for the design of critical systems for Major Hazardson the Olympus TLP. Major Hazards such as blowout fires, large wellbayexplosions, and process releases are addressed. Optimization of PFPrequirements and blast mitigation is demonstrated for critical systems such asthe Temporary Refuge (TR), Drill rig, Flare Boom, Primary Structures, ProcessVessels, Occupied Buildings, and Crane. In the case of the Drill Rig, fire andblast assessment is aligned with a key recommendation from the United StatesCoast Guard Deepwater Deepwater Horizon investigation report.

Credible Design Scenarios are identified for Major Accident Hazards (MAHs) andused to assess the inherent strength of the proposed design through FireDegradation, Blast Structural Assessment, and TR Impairment studies. Whennecessary design improvements were identified, further work was undertaken tooptimize PFP application and blast resistance while delivering an ALARP design. In the process, full consideration was given to minimizing design changes, saving weight, and reducing maintenance problems during the life of thefacility. In some instances this produced a superior result relative to initialengineering assumptions about PFP application and blast design.
Overcoming Field Development Challenges in Depleting Ultra HPHT West Franklin Field
Authors: Jezdimirovic Slobodan , Marple Andrew , Maleyran Jean-Marc , Millancourt Francois Jean
Published: April 2012

West Franklin is an HPHT field in the Central Graben Area of the UK ContinentalShelf discovered in 2003. The field went into production in 2007 via a welldrilled from the Franklin Well Head Platform (WHP) of the existingElgin/Franklin facilities. Results from a second well generated the case for asecond phase of field development.

Development studies at the preliminary stage of the second phase eliminated theoption of further field development by drilling from the existinginfrastructure. Subsea development was also screened out due to technology gapsin subsea HPHT applications. A new WHP tied back to the existing Elgin/Franklinfacilities became the prime development candidate in the conceptual stage. However, time was of the essence as the two existing wells were still producingand depleting the reservoir, introducing uncertainty to the drillingfeasibility due to the phenomenon described as the "infill challenge". In orderto mitigate these drilling risks the development strategy was to pre-drill thewells. Drilling commenced from a subsea template and continued until a jacketwas designed, fabricated and installed in September 2012. The acceleration ofthe jacket installation minimized the number of wells to be reconnected from adeep set tie back and allowed the other wells to be completed from a wellaccess deck. The WHP topsides will be installed later in 2013.

In addition to managing multiple interfaces the project faced significanttechnical challenges generated by ultra HPHT reservoir conditions. Overcomingthese in time to optimize the design was difficult in itself i.e. topsideslayout/orientation and associated jacket appurtenances; design of the OverPressure Protection System and risers and their installation within the jacket. The list goes on and includes timely co-venturer and UK regulatoryapprovals.

This paper addresses the key challenges and decisions taken along a stageddesign and approval process for a development in an ultra HPHT environment.

Introduction

The Elgin/Franklin field is located in the Central Graben Area of the NorthSea approximately 240km east of Aberdeen in 92m water depth (Figure 1). Thereservoirs (shore face sandstone of Late Jurassic age) are 5,500m deep andpresent ultra high pressures (1,100bar) and temperatures (200degC).