bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrity of High Pressure Relief Systems
Authors: Smeulers J. P. , Hageraats-Ponomareva S. V. 
Published: September 2011

Abstract
Pressure relief systems are applied in various installations in the Oil & Gas industry. Especially in upstream applications, the importance of relief systems cannot be underestimated, because failure can lead to release of hydrocarbons to the environment. The upstream production facilities (e.g. subsea production systems, assets on a production platform) are usually protected from overpressurarisation by a HIPPS which shuts in the well when local pressure levels exceed a certain threshold. In addition to this, a pressure relief line is often installed as a last safety barrier when shut-in of the well by means of the HIPPS fails. Especially if gas is produced from a high pressure high temperature reservoir (HPHT), the relief system should be designed such that it can sustain the extreme flow conditions that occur when it is activated.
Serious incidents with failing relief lines in the past have raised the attention for the integrity of relief systems and lead to requests for integrity evaluation of newly designed relief systems. Integrity evaluations should address the following dynamic flow phenomena: 1) the generation of shock waves when the relief valve is opened instantly; 2) the occurrence of two-phase flow in the relief line and the corresponding formation of slugs; 3) acoustic fatigue, which is the result of extremely high sound levels in the line generated by the expansion of gas through the relief valve; and 4) possible relief valve instability. This paper addresses how aforementioned phenomena can potentially affect the mechanical integrity of pressure relief systems. A case study of a typical pressure relief system is used to assess the dynamic flow phenomena and how these relate to the mechanical integrity of the relief system. The methods that are discussed in this paper can be directly applied to such mechanical integrity analyses.
Benefits and Limitations of Assisted History Matching
Authors: Cancelliere M. , Verga F. , Viberti D. 
Published: September 2011

Abstract
Some years ago, a new methodology called automatic history matching was approached by the scientific community. The idea consisted in treating history matching as an optimization process, i.e. defining a cost function representative of the discrepancy between measured (real) and simulated data, and in minimizing the cost function. The minimization of the cost function can be obtained by applying a suitable optimization algorithm. Optimization and non-linear programming were not new methodologies in the field of applied mathematics. However, the selection of the most adequate optimization algorithm among those available in the technical literature is not trivial, and the number of independent variables involved in complex reservoir simulation does not make the solution of the optimization problem a standard procedure. In fact, the main criticalities of a history matching process change for each analyzed reservoir. As a consequence, the identification of an optimization methodology appropriate for a wide variety of reservoirs is quite impossible. Therefore, automatic history matching remains a dream and, more realistically, assisted history matching can be the target.
The concept of assisted history matching is that reservoir engineers are still in charge of reservoir model calibration, but they can rely on reliable optimization tools to better explore the parameter space and to speed up the convergence to one or more solutions.
The aim of this paper consists in discussing benefits, limitations and drawbacks of assisted history matching by applying new techniques, based on multi objective optimization and heuristic strategies. Attention is focused on the possibility offered by these methodologies of obtaining a number of calibrated reservoir models. Each of these models can then be used for field performance prediction so as to obtain a representative evaluation of the risks associated to any reservoir development scenario.
12 Days Under The Ice With An AUV
Authors: Ferguson James , Laframboise Jean-Marc , Mills Richard 
Published: September 2011

Abstract
In March and April 2010, an ISE Explorer Autonomous Underwater Vehicle (AUV), built for Natural Resources Canada (NRCan), was deployed to Canada’s high Arctic. Its mission was to undertake under-ice bathymetric surveys in support of Canada’s submission to establish the outer limits of its continental shelf under the United Nations Convention on the Law of the Sea (UNCLOS). During this deployment several under-ice records were broken and several new technologies were demonstrated.
NRCan’s AUV is an ISE Explorer class vehicle, with several innovative additions to make it suitable for arctic survey work. Most notable are a 4000 m depth rated variable ballast system, a 1500 Hz long-range homing system, and under-ice charging and data transfer capabilities. A Short-Range Localization (SRL) system was also developed for close range positioning. The homing and SRL systems were developed by Canadian defense scientists and engineers at DRDC (Defence Research and Development Canada).
The Explorer’s range was extended to approximately 450 km by adding a hull section to accommodate extra batteries. The scientific payload onboard included a Seabird SBE49 Conductivity-Temperature-Depth (CTD) sensor, Knudsen singlebeam echosounder, and a Kongsberg Simrad EM2000 multibeam echosounder. In order to optimize battery endurance, the plan was to only turn on the EM2000 at strategic locations (i.e. potential sea mounts) along the mission path.
The Main Camp near Borden Island (78°14’N, 112°39’W) was the launch site for the AUV. It was launched from an 8 m by 3 m ice hole, cut through 2 – 3 m thick ice. After several test dives, the first mission was a transit to a Remote Camp, 320 km to the northwest. The AUV autonomously homed into the Remote Camp and was secured with the help of a small remotely operated vehicle (ROV). Without being removed from the water, it was charged and survey data was downloaded, all through a 1.3 m by 2 m ice hole. Subsequently, a second survey mission was undertaken in a region known as the Sever Spur (~79°N, 115°W), which returned back to the Remote Camp. Finally, it embarked on a return transit mission to the Main Camp for recovery. The AUV spent 10 days under ice before being successfully recovered. In total, close to 1000 km of under-ice survey was accomplished between the 3 missions. The AUV reached depths of 3160 m and transited at an average speed of 1.5 m/s at an altitude of 130 m above the seabed. From operating entirely under ice, to surveying in such a challenging environment, to the distances and objectives, this is an historic milestone in AUV and polar science. ISE, DRDC and NRCan are now preparing for a 2011 deployment to collect additional arctic survey data.
Buoyancy Technology Used Effectively in Casing-Running Operations to Extend Lateral Step-Out: Multiple Case Histories Detail Application Risks, Successes, and Improved Operation Procedures
Authors: Rogers Hank , Ryen Daniel , Sparks Dale 
Published: September 2011

Abstract
Operators today face an ever-increasing demand for locating commercial reserves and producing those reserves with an emphasis on exploration and development costs. In addition to basic financial pressures, operators also strive to reduce the environmental impact of well-construction and production operations. Extended-reach drilling technology allows operators to reach recoverable reserves that were previously unreachable. Specifically, extended-reach drilling from a multipad wellsite allows significant portions of the well-construction costs to be distributed throughout multiple wells rather than being carried by an individual wellbore. Also, the capability to drill multiple wells from a single pad reduces the environmental impact of the drilling operation.
Extending the wellbore reach from a given pad depends on the location of the target formation. Depth, horizontal distance, and production type significantly affect the type of drilling program, as well as the casing-running operation. Casing flotation is a proven technology that has been deployed in multiple fields around the world to extend the attainable lateral reach of the casing-running operation. In many wells where flotation is required, the common limiting factor that determines the maximum step out that can be achieved is based on available hook load or weight in the near-vertical section of the well. However, when smaller casing strings are used, the limiting factor is not available weight, but rather the buckling limits of the casing. In some cases, slackoff loads with small casing strings cause helical buckling and lockup of the casing before reaching total depth (TD).
This paper documents the use of flotation technology in several wells where buckling limits and subsequent casing lockup was averted to allow successful casing-running operations to be performed without the requirement of costly premium torque-shouldered connections. Additionally, the paper presents improved processes used successfully that significantly increased operational efficiencies before cementing operations. Detailed prejob planning and computer simulations are provided to demonstrate the limits without casing flotation and the stepout achieved with casing flotation.
Pulsatile Lavage for the Enhancement of Pressure Ulcer Healing: A Randomized Controlled Trial
Authors: Ho Chester H. , Bensitel Toula , Wang Xiaofeng , Bogie Kath M. 
Published: September 2011

BackgroundPressure ulcer development is a common, serious complication after spinal cord injury (SCI). Although many biophysical agents are available for treatment, few randomized controlled trials of their efficacy have been done.ObjectiveThe study objective was to examine the efficacy of low-pressure pulsatile lavage treatment for stage III and IV pressure ulcers in people with SCI.DesignThis study was a randomized controlled trial. Participants and assessors were unaware of intervention assignments.SettingThis study was conducted in an SCI tertiary care center inpatient unit.ParticipantsParticipants were 28 people with SCI and stage III and IV pelvic pressure ulcers; 14 participants each were randomly assigned to treatment and control (sham treatment) groups.InterventionDaily low-pressure pulsatile lavage treatment with 1 L of normal saline at 11 psi of pressure was applied to the treatment group along with standard dressing changes. The control group received only sham treatment and standard dressing changes.MeasurementsLinear and volume measurements of pressure ulcer dimensions were obtained weekly for 3 weeks.ResultsStatistical analysis with the t test revealed no statistically significant difference in demographics between groups. Random-coefficient models for analysis of linear and volume measurements revealed improvements over time for both groups. Time trend analysis revealed greater measurement decreases for the treatment group. Differences in rates of change (with 95% confidence intervals) for treatment and control groups, respectively, were: depth, −0.24 (0.09 to −0.58) cm/wk; width, −0.16 (0.06 to −0.39) cm/wk; length, −0.47 (0.18 to −1.12) cm/wk; and volume, −0.33 (0.13 to −0.80) cm3/wk.LimitationsStudy limitations were small sample size and inclusion of only one site. Additionally, participants were not queried about their group assignments.ConclusionsPulsatile lavage enhanced stage III and IV pelvic pressure ulcer healing rates in people with SCI relative to standard pressure ulcer treatment alone.
La Libye après Kadhafi : essai de prospective géopolitique du conflit libyen
Authors: Daguzan Jean-François , Moisseron Jean-Yves 
Published: September 2011

Après quarante-deux ans de règne, le colonel Kadhafi va, d’une manière ou d’une autre, céder la place. Le mode de gouvernement ainsi que rôle de ce pays sur la sphère méditerranéo-maghrébo-africaine vont en être profondément modifiés. Nous changeons d’ère. Par la contrainte, l’obstination et son génie propre, le « guide » de la Libye avait imposé en interne un modèle de stabilité dans l’instabilité et, au plan externe, une politique extérieure poussée par une obsession unitaire variable (panarabisme, puis panafricanisme) et la préscience d’un destin libyen universel. La fin annoncée du régime renvoie donc à des réalités prosaïques : quelle sera la nouvelle structure de l’État libyen, s’il parvient déjà à se recomposer ? Comment sera comblé le vide stratégique laissé par la disparition des politiques kadhafiennes et quel sera l’impact de la guerre ? De fait, l’espace géopolitique maghrébin et sahélien redevient ouvert. La Libye de Kadhafi, même si elle soutenait les mouvements touaregs, contenait les migrations et luttait contre AQMI. Tout en s’étant « techniquement » ralliée au modèle occidental, elle était aussi un espace indépendant des rapports de forces globaux. Cet article essaye d’analyser les conséquences de la chute du régime de Kadhafi dans une perspective géopolitique.
Enchevêtrements géopolitiques autour de la lutte contre le terrorisme dans le Sahara
Authors: Tisseron Antonin 
Published: September 2011

À la suite des attentats du 11 septembre 2001, l’Afrique du Nord est devenue pour les États-Unis un nouveau front de la « guerre contre le terrorisme ». Cet interventionnisme, dans une zone dans laquelle la France est traditionnellement présente, s’est toutefois heurté aux logiques et dynamiques géopolitiques à l’œuvre dans la région. Chaque acteur possède en effet ses objectifs, faisant du Sahara un espace dans lequel s’enchevêtrent des enjeux de pouvoir, de contrôle et d’influence au nom de la sécurité. Dans ce contexte, la volonté de donner un visage local à la lutte contre le terrorisme a jusque-là été limitée par l’absence de consensus sur la stratégie à adopter et le manque d’engagement du Mali. Si la guerre civile en Libye semble stimuler les dynamiques de rapprochement dans la région, la lutte contre le terrorisme et la criminalité dans la région reste cependant étroitement dépendante des capacités des États, de leurs relations avec les populations, et de leurs intérêts à toutes les échelles.
Portée et limites de l'hégémonie algérienne dans l'aire sahélo-maghrébine
Authors: Chena Salim 
Published: September 2011

L’Algérie semble être la puissance hégémonique au Maghreb et au Sahel dans la mesure où elle dispose de ressources énergétiques stratégiques, d’une position privilégiée dans la lutte antiterroriste et d’un rôle important dans la répression des migrants irréguliers au Sahara et en Méditerranée. Ses imposantes ressources financières lui garantissent en outre une indépendance certaine dans ses politiques intérieure comme extérieure. En apparence univoque, cette situation doit faire face à de nombreux défis : des rivalités régionales anciennes, des alliances incertaines au Sahel, des acteurs extrarégionaux de plus en plus investis, une contestation sociale et politique intense. Cet article cherche à mettre en évidence les atouts et les limites de la mise en œuvre de la politique régionale algérienne.
Le Sahel comme espace de transit des stupéfiants. Acteurs et conséquences politiques
Authors: Julien Simon 
Published: September 2011

Les pays sahéliens sont traversés depuis quelques années par des routes de trafics de stupéfiants, la cocaïne et le haschich. Cette arrivée témoigne à la fois de la transformation de la géoéconomie globale de ces deux produits mais également du renforcement des pays sahéliens dans leur spécialisation d’espace de transit, qui est l’un des modes de l’insertion de ces pays dans l’économie mondiale. En effet, si l’on prend l’exemple de la cocaïne, ce produit est arrivé en Afrique de l’Ouest et au Sahel au milieu des années 2000 en raison de l’émergence de l’Europe comme premier marché de consommation et de la dangerosité progressive (pour les trafiquants) des routes plus directes entre les zones de production en Amérique latine et l’Europe. Si l’on dresse une typologie des acteurs de ce trafic dans les pays traversés, on doit s’éloigner du modèle d’une mafia globale qui pourrait se payer des relais locaux. En effet, les acteurs africains, notamment ce que l’on peut appeler des mafias d’État dans certains pays, semblent incontournables. Les profits générés par ces trafics participent aux économies nationales mais ont déjà commencé à financer la politique et donc à produire du politique.
Circulations marchandes au Sahara : entre licite et illicite
Authors: Scheele Judith 
Published: September 2011

Les échanges régionaux sont nécessaires aux économies locales sahariennes. Au gré de la conjoncture, ces échanges et les réseaux qui les sous-tendent ont toujours servi de relais à d’autres courants commerciaux : transsahariens et transrégionaux. À la main-d’œuvre, au thé, au coton ou au sucre convoyés vers et à travers le Sahara au XIX e siècle se sont ainsi ajoutés, au cours du XX e siècle, des produits manufacturés provenant des usines subventionnées du Maghreb, puis des marchandises illicites, comme des cigarettes de contrebande, des voitures volées, des armes et de la drogue. Or ces trafics ne représentent qu’une partie minime des échanges sur le terrain et s’inscrivent nécessairement dans des structures familiales plus anciennes, décentralisées, flexibles et pour partie vulnérables aux interventions extérieures. Aujourd’hui comme par le passé, c’est avant tout la capacité à se baser sur ces structures régionales, tout en s’adaptant à la conjoncture, qui permet de réussir.
Sirtuin 1 Promotes Th2 Responses and Airway Allergy by Repressing Peroxisome Proliferator-Activated Receptor-γ Activity in Dendritic Cells
Authors: Legutko Agnieszka , Marichal Thomas , Fiévez Laurence , Bedoret Denis , Mayer Alice , de Vries Hilda , Klotz Luisa , Drion Pierre-Vincent , Heirman Carlo , Cataldo Didier , Louis Renaud , Thielemans Kris , Andris Fabienne , Leo Oberdan , Lekeux Pierre , Desmet Christophe J. , Bureau Fabrice 
Published: September 2011

Abstract
Sirtuins are a unique class of NAD+-dependent deacetylases that regulate diverse biological functions such as aging, metabolism, and stress resistance. Recently, it has been shown that sirtuins may have anti-inflammatory activities by inhibiting proinflammatory transcription factors such as NF-κB. In contrast, we report in this study that pharmacological inhibition of sirtuins dampens adaptive Th2 responses and subsequent allergic inflammation by interfering with lung dendritic cell (DC) function in a mouse model of airway allergy. Using genetic engineering, we demonstrate that sirtuin 1 represses the activity of the nuclear receptor peroxisome proliferator-activated receptor-γ in DCs, thereby favoring their maturation toward a pro-Th2 phenotype. This study reveals a previously unappreciated function of sirtuin 1 in the regulation of DC function and Th2 responses, thus shedding new light on our current knowledge on the regulation of inflammatory processes by sirtuins.
Invariant NKT Cell Defects in Vitamin D Receptor Knockout Mice Prevents Experimental Lung Inflammation
Authors: Yu Sanhong , Zhao Jun , Cantorna Margherita T. 
Published: September 2011

Abstract
Vitamin D receptor (VDR) deficiency (knockout [KO]) results in a failure of mice to generate an airway hyperreactivity (AHR) response on both the BALB/c and C57BL/6 background. The cause of the failed AHR response is the defective population of invariant NKT (iNKT) cells in the VDR KO mice because wild-type (WT) iNKT cells rescued the AHR response. VDR KO mice had significantly fewer iNKT cells and normal numbers of T cells in the spleen compared with WT mice. In BALB/c VDR KO mice, the reduced frequencies of iNKT cells were not apparent in the liver or thymus. VDR KO and WT Th2 cells produced similar levels of IFN-γ and IL-5. On the BALB/c background, Th2 cells from VDR KO mice produced less IL-13, whereas on the C57BL/6 background, Th2 cells from VDR KO mice produced less IL-4. Conversely, VDR KO iNKT cells were defective for the production of multiple cytokines (BALB/c: IL-4, IL-5, and IL-13; C57BL/6: IL-4 and IL-17). Despite relatively normal Th2 responses, BALB/c and C57BL/6 VDR KO mice failed to develop AHR responses. The defect in iNKT cells as a result of the VDR KO was more important than the highly susceptible Th2 background of the BALB/c mice. Defective iNKT cell responses in the absence of the VDR result in the failure to generate AHR responses in the lung. The implication of these mechanistic findings for human asthma requires further investigation.
EBI2 Operates Independently of but in Cooperation with CXCR5 and CCR7 To Direct B Cell Migration and Organization in Follicles and the Germinal Center
Authors: Gatto Dominique , Wood Katherine , Brink Robert 
Published: September 2011

Abstract
Migration of B cells within lymphoid follicles is controlled by the chemokine receptors CXCR5 and CCR7 and the G-protein-coupled receptor EBI2 (GPR183). Whereas CXCR5 and CCR7 are known to mediate migration toward their respective chemokine ligands, it is unclear whether EBI2 acts by modulating these processes or by directly mediating chemotaxis toward its own spatially restricted ligand. It is also unknown how signals from these three receptors are integrated to control B cell localization. To answer these questions, we generated compound knockout mice deficient in expression of EBI2, CXCR5, or CCR7. Analysis of these mice revealed that EBI2 mediates B cell migration toward the outer areas of follicles and to bridging channels of the spleen independent of both CXCR5 and CCR7. Migratory signals delivered by EBI2 were shown to control B cell organization within the spleen and to be particularly important for positioning activated B cells in the early stages of Ab responses. An additional minor role for EBI2 was identified in the organization and affinity maturation of B cells in germinal centers. Thus, EBI2-mediated chemotaxis provides a third dimension to B cell migration that balances and integrates with the inputs from CXCR5 and CCR7 to determine B cell positioning.
B Cell Depletion Enhances T Regulatory Cell Activity Essential in the Suppression of Arthritis
Authors: Hamel Keith M. , Cao Yanxia , Ashaye Susan , Wang Yumei , Dunn Robert , Kehry Marilyn R. , Glant Tibor T. , Finnegan Alison 
Published: September 2011

Abstract
The efficacy of B cell-depletion therapy in rheumatoid arthritis has driven interest in understanding the mechanism. Because the decrease in autoantibodies in rheumatoid arthritis does not necessarily correlate with clinical outcome, other mechanisms may be operative. We previously reported that in proteoglycan-induced arthritis (PGIA), B cell-depletion inhibits autoreactive T cell responses. Recent studies in B cell-depletion therapy also indicate a role for B cells in suppressing regulatory mechanisms. In this study, we demonstrate that B cells inhibited both the expansion and function of T regulatory (Treg) cells in PGIA. Using an anti-CD20 mAb, we depleted B cells from mice with PGIA and assessed the Treg cell population. Compared to control Ab-treated mice, Treg cell percentages were elevated in B cell-depleted mice, with a higher proportion of CD4+ T cells expressing Foxp3 and CD25. On a per-cell basis, CD4+CD25+ cells from B cell-depleted mice expressed increased amounts of Foxp3 and were significantly more suppressive than those from control Ab-treated mice. The depletion of Treg cells with an anti-CD25 mAb concurrent with B cell-depletion therapy restored the severity of PGIA to levels equal to untreated mice. Although titers of autoantibodies did not recover to untreated levels, CD4+ T cell recall responses to the immunizing Ag returned as measured by T cell proliferation and cytokine production. Thus, B cells have the capacity to regulate inflammatory responses by enhancing effector T cells along with suppressing Treg cells.