bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Technology Yields Ultrahigh-Strength Proppant
Authors: Palisch T.. , Duenckel R.. , Wilson B.. 
Published: March 2015

Summary
Nearly all of the proppant available on the market today can be classified into one of three tiers—sand, resin-coated sand, or ceramic. The products contained in these three tiers have served the industry well and have typically covered the broad spectrum of applications required by completions engineers. However, with the development of deeper reservoirs and the ongoing look at geothermal and steamflood applications, there now exists a gap in proppant technology. No conventional proppant can provide sufficient conductivity at the 20,000-psi (and higher) closure stresses anticipated in the Lower Tertiary formations in the deep Gulf of Mexico. Similarly, no conventional proppant can adequately withstand the harsh chemical conditions in many geothermal and steamflood applications.
The industry has begun to address this gap in performance with the development of higher-strength proppants. One such proppant has been developed and commercialized to meet these challenges. It achieves twice the baseline conductivity of any conventional proppant at these high stresses, and should also provide additional advantages because of increased durability. This paper will review the step-change advancements achieved by this new proppant, including improvements in both raw materials and manufacturing processes. It will present properties never seen before in regard to proppant shape, sizing, and strength. Extensive laboratory testing has been completed and will be presented to demonstrate the superior performance of the proppant in harsh conditions.
The paper will also outline the expected applications for this product, including areas in which increased production rates, superior estimated ultimate recovery, lower erosivity, and reduced equipment wear are primary concerns. Field applications are under way to properly assess the implications of these findings.
This paper should be beneficial to all completions engineers and production technologists currently working in regions with high-stress applications (≥ 14,000 psi) or other harsh conditions such as those of steamflooding and geothermal applications.
Structure, Stoichiometry, and Modeling of Mixed Calcium Magnesium Phosphonate Precipitation Squeeze-Inhibitor Complexes
Authors: Shaw S.S.. S. , Sorbie K.S.. S. 
Published: March 2015

Summary
In this paper, the properties of precipitated “mixed” calcium and magnesium phosphonate scale-inhibitor (SI) complexes formed by nine common phosphonate species are investigated. These complexes are of the form SI–CaN1–MgN2, where the stoichiometry (Ca2+/SI and Mg2+/SI molar ratios; i.e., N1 and N2, respectively) in various precipitates is established experimentally, and the effect of solution pH on the stoichiometry is determined. Static precipitation tests were performed by varying the amounts of Ca2+ and Mg2+ present in the system (at a constant ionic strength) at test temperatures ranging from 20 to 95°C and at a fixed [SI] = 2,000 ppm. The stoichiometries of the solid precipitates were determined by assaying for Ca2+, Mg2+, and P in the supernatant liquid, under each test condition, by inductively coupled plasma spectroscopy. It is shown experimentally that for all nine phosphonates tested, these stoichiometries (i.e., N1 and N2 in SI–CaN1–MgN2) depend on (1) the nature of the SI (i.e., Mg2+ binding sites per molecule); (2) the solution pH, which affects the speciation of the SI; (3) the relative magnitude of the SI binding constants to Ca2+ and Mg2+ at the test pH (Kb1 and Kb2, respectively); and (4) the solution molar ratio of Mg2+/Ca2+. It is found that, as pH increases, the combined molar ratio of Ca2+ and Mg2+ to SI (i.e., Nt = N1 + N2 in the complex) increases up to a theoretical maximum Nt,max, depending on the chemical structure of the phosphonate [corroborating earlier work SPE-155114-MS (Shaw et al. 2012c) and SPE-164051-PA (Shaw and Sorbie 2014a)]. These functionality data are useful in a practical sense when performing SI-squeeze treatments in combination with Ca2+. In addition, the precipitation behavior of the various compounds is modeled theoretically by developing and solving a set of simplified equilibrium equations. Very good agreement is seen between the modeling and experimental results. Such models can be used directly in the simulation of field phosphonate precipitation-squeeze treatments to design and optimize squeeze lifetimes.
Synergistic Properties of Phosphonate and Polymeric Scale-Inhibitor Blends for Barium Sulfate Scale Inhibition
Authors: Shaw S.S.. S. , Sorbie K.S.. S. 
Published: March 2015

Summary
Barium sulfate is one of the most-difficult types of scale to inhibit in oil- and gas-production systems because of its physical hardness and its chemical and thermal stability. Barium sulfate is most commonly inhibited with either phosphonate or polymeric scale inhibitors (SIs) deployed at substoichiometric concentrations. What is less well-known in the oil industry is the effect resulting from the use of combinations of two (or more) SIs synergistically for enhanced scale-inhibition performance. A positive “synergistic” effect would be one in which, for example, 5 ppm of A + 5 ppm of B performed better than 10 ppm of either A or B. In this paper, a series of static barium sulfate inhibition-efficiency (IE) test results are presented, in which a series of pairs of SIs have been tested to determine their synergistic properties at pH 5.5 and 95°C. Polymers can be blended with phosphonates or, alternatively, pairs of phosphonates or polymers may be applied. In all cases, the synergistic IE is compared with the IE of each SI tested independently at the mass dosage (i.e., the same concentration in mg/L or ppm). Each separate single SI used in the work has been tested previously for barium sulfate IE at pH 5.5 and 95°C to determine the minimum inhibitor concentration (MIC) for each species (Shaw et al 2012a, b). Previously, nine phosphonate and nine polymeric SIs were tested individually; in this work, 34 SI combinations have been tested to examine their synergistic properties. The MICs of the synergistic blends are compared with the normal MICs of the individual SIs. Surprisingly, in most cases, the IE of the blends is usually higher over the range of SI concentrations tested (i.e., the MIC of the blend is lower), compared with that of each SI tested separately. Certain “pairs” of SIs used together yield a significantly beneficial effect (e.g., DETPMP and HMTPMP, both pentaphosphonates). Some mechanistic reasons for these synergistic pairs working particularly well are suggested.
A New Simulation Model for a Beam-Pumping System Applied in Energy Saving and Resource-Consumption Reduction
Authors: Xing Mingming , Dong Shimin 
Published: March 2015

Summary
There are nearly 920,000 oil-producing wells worldwide, approximately 87% of which are operated with an artificial-lift method. A rough distribution of these wells shows that 71% use a beam-pumping system, 16% use electrical submersible pumps, 7% use gas lift, and 6% use other forms of lifting systems (Alemi et al. 2011; Liu and Qi. 2011; Ghareeb et al. 2007; Xu et al. 2012). The great majority of the world's oil wells are on artificial lift; therefore, they require large amounts of external electric energy to produce hydrocarbons because the available formation energy is not sufficient to move the well fluids to the surface. On the basis of the 920,000 wells, with 10 kW/hr of consumed power for each well and oil production for 350 days of the year, beam-pumping systems consume approximately 4.77×1010 kW-hr of power per year worldwide. If the power consumption can be decreased by 20% with an energy-saving technique, that alone will help to save 0.95×1010 kW-hr of electricity per year around the world. Therefore, enormous economic benefits will be created by enhancing the system efficiency and reducing the consumption of energy.
In this paper, a new comprehensive simulation method of efficiency optimization for a sucker-rod pumping system is presented. Our new method combines a slip model of the surface-transmission system (STS) with a closely coupled model of the downhole rod-string vibration to provide an improved method for calculating the motion of a rod string and the power requirements for a conventional sucker-rod pumping system. The new model proposed in this paper will provide an improved prediction of the power requirements for conventional sucker-rod pumping systems, and the results will be significantly improved as the amount of slip in the STS increases. The new model is verified by comparing it with the available analytical solutions, and good agreement is found. Real application in a high-energy-consumption oil field shows that the new model in this paper will result in significant improvements in system design, especially when the oil wells have a small-diameter pump and high stroke frequency.
Systémique, science et sorcellerie
Authors: Kinoo Philippe 
Published: March 2015

À partir d’une expérience de formation interactive avec des intervenants psychosociaux en République Démocratique du Congo, l’auteur compare le modèle scientifique biopsychosocial occidental et le modèle spirituel africain. Il met en parallèle l’apparition d’enfants désignés sorciers en R.D.C. et les enfants diagnostiqués TDAH/ADHD en Occident. L’abus de croyance, tant côté « spirituel » que « scientifique » est stigmatisé.
Du mythe et de la psychothérapie
Authors: Mariotti Mauro 
Published: March 2015

Le Mythe est le garant du temps et du système : cet article souligne l’isomorphisme entre la famille et la psychothérapie. Nous avançons l’hypothèse que l’équilibre entre morphogenèse et morphostasie est maintenu par le mythe. Nous proposons les concepts de temps condensé et de temps existentiels ainsi que ceux de forces génératives et performatives qui déterminent le processus d’individuation des familles et des thérapeutes. Nous soulignons la similitude des cycles de vie des familles et des psychothérapeutes en nous centrant sur les narrations et les mécanismes de construction et de déconstruction des mythes.
Démocratie locale : changement d'horizon ?
Authors: Vanier Martin 
Published: March 2015

Si la vie quotidienne des citoyens semble de plus en plus s’articuler en réseaux, la démocratie, elle, est encore strictement ancrée dans les logiques territoriales, et de ce fait limitée, car de plus en plus de décisions se prennent à des niveaux interterritoriaux. Comment étendre le champ de la démocratie à partir du territoire, mais sans s’y limiter ? Participation des usagers, collectifs de biens communs, les idées existent, mais elles peinent pour l’instant à s’imposer.
Peut-on penser une cybergéographie ?
Authors: Robine Jérémy , Salamatian Kavé 
Published: March 2015

L’Internet et le cyberespace sont aujourd’hui des réalités incontournables du monde contemporain, et en géopolitique bien des événements récents en ont souligné l’importance. Cependant, ces deux termes d’Internet et de cyberespace ne se recouvrent pas. L’Internet est un réseau bâti sur du réel, composé de fibres optiques, de liaisons par satellites et de machines qui sont situées dans l’espace terrestre ; le cyberespace regroupe les applications qui exploitent l’Internet et semble s’échapper de l’espace terrestre, pour en former un nouveau. L’analyse géopolitique doit, elle aussi, distinguer ces deux plans. Tout d’abord, et au travers de quelques exemples (Iran, France, Syrie), il convient de porter un regard géographique sur les infrastructures de l’Internet. Elles peuvent être des cibles en situation de conflit et, plus généralement, leur organisation dans les territoires pose de nombreux problèmes classiques de géographie ou de géopolitique, en termes d’aménagement du territoire ou d’inégalités spatiales. Dans un second temps, et à titre d’ébauche, cet article tente d’imaginer ce que sera peut-être demain la cybergéographie, discipline visant à étudier « spatialement » le rapport des humains au cyberespace, par analogie avec la géographie qui a pour objet leurs rapports avec l’espace terrestre. Cela impliquera d’élaborer les outils d’une description du cyberespace en quelque sorte de l’intérieur, et pose de nombreuses questions abstraites et théoriques.
De Tallinn &#224; Las Vegas, une cyberattaque d&#8217;importance justifie-t-elle une r&#233;ponse cin&#233;tique ?
Authors: Libicki Martin C. 
Published: March 2015

À l’heure où l’on cherche à établir des normes et des règles internationales dans le cyberespace, on trouve deux écoles. D’un côté, le Manuel de Tallinn , rédigé par un groupe d’experts sous les auspices de l’Otan, analyse comment le droit des conflits armés s’applique au cyberespace. Les attaques dans le domaine du cyberespace ne différeraient en rien des autres formes d’attaques et la légitime défense autoriserait les nations à répondre violemment, tant qu’il y a une forme de proportionnalité entre les dommages causés par la cyberattaque initiale et la réponse cinétique. D’un autre côté, il y a ce que l’on pourrait appeler les règles de Las Vegas : ce qui se passe dans le cyberespace ne sort pas du cyberespace. Ainsi, aucune cyberattaque, même si elle cause des dommages conséquents, y compris la mort, ne mérite d’entraîner une réponse cinétique. Cette position repose sur la démonstration que, du fait de l’engrenage des ripostes, celles-ci risqueraient de provoquer des dégâts beaucoup plus dramatiques pour les populations.
Les connaissances dans le marché
Authors: Le Velly Ronan , Goulet Frédéric , Mallard Alexandre 
Published: March 2015

La sociologie économique n’ignore pas la question de la connaissance dès lors que l’on considère la façon dont les ressorts de l’action économique y ont été envisagés. Nombre de travaux renvoient ainsi à un enjeu socio-cognitif fondamental : l’interprétation des situations et l’anticipation des conséquences des actions. Les réseaux, la culture, les dispositifs, les institutions, les entrepreneurs, la concurrence ou encore la qualité, peuvent être relues au regard des enjeux de mobilisation des connaissances dans l’action qui les concernant. Trois thématiques sont ici approfondies : l’incertitude, les problèmes liés à l’absence ou l’instabilité des connaissances dans la définition de la qualité des biens ; l’hétérogénéité des régimes et des types de connaissances mobilisées dans la valuation des biens ; la performativité des connaissances économiques dans le cas de la marchandisation de la production de ces connaissances.
La strategie de diversification d'ITOYA : problemes et perspectives
Authors: Edzoualiko Nelly Bertille 
Published: March 2015

La stratégie de diversification constitue l’une des manœuvres stratégiques que les entreprises choisissent pour réduire les risques liés au déclin des activités de base des entreprises. Dans un contexte de turbulences comme l’est l’environnement africain en général, et celui de la République du Congo en particulier, ce choix stratégique a été une décision stratégique prise par les PME au Congo. Parmi elles, on a la société ITOYA SARL qui, en effet, a développé plusieurs activités stratégiques : la menuiserie, l’activité agroalimentaire (la boulangerie), le transport en commun, l’activité agro-pastorale, et construction. L’étude de la diversification d’ ITOYA a permis de comprendre le type de stratégie mise en œuvre, d’identifier les problèmes auxquels l’entreprise est confrontée dans la gestion de ses activités stratégiques et de suggérer des solutions d’améliorations. ITOYA a mis en œuvre la stratégie conglomérale. Pour identifier ses problèmes, l’analyse stratégique s’est faite en utilisant la matrice SWOT . Parmi les résultats obtenus, on note particulièrement l’absence des études de faisabilité avant le lancement des activités qui constitue, en définitive, la grosse faiblesse identifiée par l’étude.
L'impact de la strategie sur le contenu des tableaux de bord : cas des entreprises au Maroc
Authors: Elhamma Azzouz 
Published: March 2015

Durant ces dernières décennies, les systèmes de mesure de la performance, notamment les tableaux de bord, ont fait l’objet de plusieurs travaux de recherche dans les pays développés. Or ce type de recherches reste encore trop limité dans plusieurs pays en développement comme le Maroc par exemple. Cet article examine les indicateurs intégrés dans les tableaux de bord de 62 entreprises installées au Maroc et leur influence par la stratégie. Les résultats de cette recherche montrent que les tableaux de bord tendent à devenir plus « équilibrés » et se rapprochent du balanced scorecard lorsque la stratégie s’oriente vers la prospection.
L'évaluation du risque de crédit des entreprises: cas de la banque congolaise de l'habitat
Authors: Makany Joanna N.S. Julie , Gabsoubo Yienezoune Chantal 
Published: March 2015

Le risque de crédit est aujourd’hui au cœur des préoccupations bancaires. Cependant, accorder un crédit est un acte complexe ; il est lié à des risques dont la couverture devient un principe de sauvegarde. Dans ce cadre, il est nécessaire de procéder à des évaluations afin de limiter ces risques. Pour une nouvelle banque comme la banque congolaise de l’habitat, cette précaution devient nécessaire. Notre étude a permis de montrer, sur la base des travaux du Comité de Bâle, la méthode d’évaluation pertinente au regard des exigences de la COBAC. À cet effet, les méthodes « standard » et « IRB » ont été exploitées.
Influence of Ocular Features and Incision Width on Surgically Induced Astigmatism After Cataract Surgery
Authors: Chang Shu-Wen , Su Tai-Yuan , Chen Yao-Lin 
Published: March 2015

PURPOSE:
To identify factors associated with surgically induced astigmatism (SIA) following phacoemulsification.

METHODS:
Six hundred five eyes underwent phacoemulsification with a 2.2-mm (the 2.2-mm group, n = 248) or 2.75-mm (the 2.75-mm group, n = 357) superior limbal incision. Preoperative axial length, anterior chamber depth, corneal curvature, and intra-ocular pressure were measured. Corneal curvature and intraocular pressure were measured at 1 day, 1 week, and 1, 2, and 3 months postoperatively. SIA, corneal flattening, and torque were calculated using the Alpins method. The effect of preoperative corneal astigmatism meridian on SIA was also examined. Differences in SIA between the 2.2- and 2.75-mm groups were explored, and correlations between SIA and preoperative corneal astigmatism, anterior chamber depth, axial length, age, and intraocular pressure were analyzed.

RESULTS:

SIA, corneal flattening, and torque were smaller in the 2.2-mm group than in the 2.75-mm group at 1 week (
P
= .003, .006, and .014, respectively), but not statistically different thereafter. Higher preoperative corneal astigmatism, older age, and shallower anterior chamber depth were associated with greater SIA in both groups. The effect of astigmatism meridian on SIA was more noticeable in the 2.75-mm group. Shorter axial length and lower intraocular pressures were associated with greater SIA in the 2.75-mm group but not in the 2.2-mm group.

CONCLUSIONS:
Reducing limbal incision width and considering patient age, the meridian and magnitude of corneal astigmatism, anterior chamber depth, axial length, and intraocular pressure, and adjusting the flattening component of SIA input for toric intraocular lens power calculation could potentially improve the astigmatism control in refractive lens surgery.

[
J Refract Surg
. 2015;31(2):82–88.]
Evaluation of Rotation and Visual Outcomes After Implantation of Monofocal and Multifocal Toric Intraocular Lenses
Authors: Garzón Nuria , Poyales Francisco , de Zárate Begoña Ortíz , Ruiz-García Jose Luis , Quiroga Juan Antonio 
Published: March 2015

PURPOSE:
To evaluate rotational stability and its influence on postoperative visual acuity of different monofocal and multifocal toric intraocular lenses (IOLs).

METHODS:
A prospective interventional study was designed. Ninety-one patients with a mean age of 71.65 ± 11.82 years were implanted with toric IOLs after phacoemulsification. Three monofocal toric IOLs (the Lentis LT [Oculentis, Berlin, Germany], enVista [Bausch & Lomb, Rochester, NY], and AcrySof IQ [Alcon Laboratories, Inc., Fort Worth, TX]) and one multifocal toric IOL (AcrySof IQ ReSTOR; Alcon Laboratories, Inc.) were implanted. Preoperative and postoperative images were taken to calculate the misalignment due to the marking method. To evaluate rotation in the different follow-up visits, another photograph was taken 1 hour and 1, 7 and 30 days postoperatively. Refraction, uncorrected distance visual acuity (UDVA), and corrected distance visual acuity were measured 30 days postoperatively.

RESULTS:

Postoperative UDVA was 0.1 logMAR or better in 64.6% of eyes implanted with monofocal IOLs and 46.4% of eyes implanted with multifocal IOLs. The enVista toric IOL showed the best UDVA compared to the other monofocal IOLs, with 81% of eyes with 0.1 logMAR or better. The mean misalignment in the total group studied was 0.07° ± 0.60°; 69.6% of monofocal IOLs and 67.9% of multifocal IOLs showed less than 5° of rotation. A correlation was found between postoperative UDVA and rotation in the monofocal and multifocal IOLs implanted (
r
= 0.439 [
P
< .011] and = 0.787 [
P
= .001], respectively).

CONCLUSIONS:
At 1 month postoperatively, UDVA was slightly more affected by IOL rotation in multifocal than monofocal toric IOLs. The marking method was also effective.

[
J Refract Surg
. 2015;31(2):90–97.]
Matched Comparison Study of Total and Partial Epithelium Removal in Corneal Cross-linking
Authors: Hashemi Hassan , Miraftab Mohammad , Hafezi Farhad , Asgari Soheila 
Published: March 2015

PURPOSE:To compare the 1-year results of total versus partial epithelium removal in corneal cross-linking in the treatment of progressive keratoconus.METHODS:This retrospective study compared the results of total (the total group) versus partial (the partial group) approaches of epithelium removal in corneal cross-linking. Eighty eyes of 65 patients (40 eyes in each group) were enrolled. The mean age of the participants was 25.48 ± 4.80 years and 62.5% were male. One-year changes in vision parameters, refraction, and Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) indices were compared between the two groups using repeated measures analysis of variance.RESULTS:One year after corneal cross-linking, uncorrected distance visual acuity in the total and partial group improved by 0.13 ± 0.42 and 0.12 ± 0.36 logMAR (P= .447), respectively, and corrected distance visual acuity improved by 0.00 ± 0.19 and 0.13 ± 0.20 logMAR (P= .001), respectively. Spherical equivalent decreased by 0.44 ± 1.25 diopters (D) in the total group and 0.56 ± 1.47 D in the partial group (P= .710). The decrease in maximum keratometry was 0.39 ± 0.93 and 0.01 ± 0.95 D in the total and partial group, respectively (P= .037), and the decrease in mean keratometry was 0.42 ± 0.93 and 0.00 ± 0.65 D (P= .015), respectively. Central corneal thickness decreased by 18.39 ± 20.66μm in the total group and 0.11 ± 13.29μm in the partial group (P< .001).CONCLUSIONS:One year after corneal cross-linking, both approaches showed similar results in terms of uncorrected distance visual acuity. With the partial approach, there was slightly better corrected distance visual acuity improvement and central corneal thickness maintenance, but slightly better corneal flattening was achieved with the total removal. Long-term studies are needed to compare these two approaches in terms of stability of results and stopping the progression of keratoconus.[J Refract Surg. 2015;31(2):110–115.]