bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real Time Tracking of Fracture Propagation During Air Injection as an Alternative Fracturing Fluid
Authors: Hascakir B. 
Published: October 2015

Abstract
Hydraulic fracturing is a proven technology that is implemented through injecting highly pressurized water into tight formations. The excessive amount of water use during the process poses serious environmental problems. To address this issue, we propose and study the feasibility of a new fracturing technology utilizing air injection as an alternative fracturing fluid for tight oil and gas reservoirs. Samples from Eagle Ford and Green River formations are selected to study due to their compositional differences; carbonate rich and kerogen rich, respectively. Samples were first characterized with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA) to determine their mineralogical and organic content. A special core holder was designed to visualize the fracture formation during experiments with X-Ray Computed Tomography (CT). CT scan results were analyzed for fracture formation and propagation during air injection. Experimental results show that the clay content and type during air injection play an important role on fracture formation. It has been found that the alterations in clays at elevated temperatures contribute to keep the formed fracture apertures open due to the cementing behavior of clays at high temperatures. Kerogen was found to also contribute to the formation of microfractures due to its thermal decomposition and the thermal expansion of formed gases at elevated temperatures. Furthermore, the decomposition of inorganic content, especially the carbonate content of shale samples, enhances the fracture formation. Hence, all clay rich, carbonate rich, and kerogen rich shale samples show a trend that favors effective fracturing with air. CT scan results also validate the formation and propagation of these effective fractures, and CT scans taken after one day of the core flooding experiments prove that the fractures remain open even without proppant addition. Because air is an abundant, cheap, and easy to handle injection fluid, it is an attractive alternative to water for fracturing. Our experimental results support the use of air as an alternative fracturing fluid in a promising, feasible, and low cost method for fracturing tight oil and gas reservoirs.
Refracturing Design for Underperforming Unconventional Horizontal Reservoirs
Authors: Krenger J. T. , Fraser J. , Gibson A. J. , Whitsett A. , Melcher J. , Persac S. 
Published: October 2015

Abstract
This paper discusses design considerations to increase the estimated ultimate recovery (EUR) on underperforming wells in a refracturing scenario. A method for, and case histories of, using an environmentally acceptable, self-removing particulate diverter that has proven to be successful in the refracturing efforts of horizontal unconventional reservoirs are provided. This method is typically chosen for its low cost, self-assembly, and self-removal. An outline of the design process for refracturing and post-refracturing procedures is included. The ability to add reservoir contact, restore conductivity, remediate blockage, and address depleted reservoir pressure make this technique desirable.
Different strategies can be applied when using this technique and are typically customized to the particular candidate well selected for the refracturing treatment. The treatment designs for the wells discussed in this paper were designed to increase EUR. Candidate wells for refracturing typically fall into one or more categories: understimulation occurred in the original completion, production damaging mechanisms are present, a low investment lease retention strategy was originally required, or a pressure-sink mitigation strategy is necessary for infill completions. Candidates in this paper fall into the understimulated category. A typical procedure consists of casing inspection, wellbore cleanout, possible addition of perforations, and flowback considerations.
In this study, different Haynesville shale refracturing treatments, results, and diagnostics are compared. The evolution of treatment design components, such as carrier fluid, fluid volume, proppant volume, and diverting methodology, is explained. The results and underlying theory of these changes are outlined. Pre/post-treatment production is compared, along with treatment pressure trend analysis and microseismic data.
Although performing secondary stimulation treatments is becoming more common, the industry's focus on improving production decline curves has led to a surging interest in refracturing horizontal unconventional reservoirs. Decline rates in unconventional reservoirs tend to be more rapid compared to conventional reservoirs because of their ultralow permeability, limited reservoir contact, and original completion strategy. Refracturing of these reservoirs enables the recovery of hydrocarbons trapped by these restrictions.
Using the Wrong Method to Estimate Stress From Depletion Causes Significant Errors in Predicting Wellbore Integrity and Fracture Geometry
Authors: Narasimhan Santhosh , McCleary Matt , Fluckiger Samuel D , Gray James , Cherian Bilu V. , Shaikh Hamza , Olaoye Olubiyi 
Published: October 2015

Abstract
When calculating the downhole stresses affecting a wellbore during depletion it has become a standard industry practice to assume only the pore pressure changes, and not the rock mechanical properties. This assumption has the potential to underestimate the total horizontal stress (Sh) causing unrealistic fracture containment. It will also overestimate the effective horizontal stress (Sh' = Sh - Biot * Pore Pressure) for open-hole wellbore failure. High effective horizontal stress assumption can potentially transform rock from brittle to ductile behavior and failure mechanics from shear to compaction and the model becomes overly conservative. Ductile and compaction failure can cause changes in well integrity, as well as changes in fracture geometry from offset infill wells. This paper will document changes in rock properties in the Bakken formation during variable depletion (10% to 65%) and recalculate rock properties (velocities, mechanical properties - Young's modulus, Poisson's ratio, and Biot's anisotropic compressibility constant) as a function of effective stress due to production in order to accurately calculate fracture geometry at an offset well and parent well bore integrity. Hydraulic fracturing simulations are performed to simulate well communication between the fractured well and the depleted parent well along with the potential to re-fracture the parent well using the pore pressure, linear, and non-linear models. Laboratory testing performed on rock samples is shown to validate the non-linear model.
Simulation of Cement Slurry Flow to Assess the Potential for Voids and Channels in Wellbore Cementing Processes
Authors: Grasinger Matthew , Li Zichang , Vuotto Alex , Brigham John , Iannacchione Anthony , Vandenbossche Julie 
Published: October 2015

Abstract
A numerical approach is presented to simulate the non-Newtonian flow of a wellbore cementing process to quantify the potential for poor drilling mud displacement efficiency and bond strength development between the cement annulus and rock formation. The approach consists of using the lattice Boltzmann method with a Bingham plastic constitutive model to represent the cement flow behavior. The lattice Boltzmann method is a pseudo-particle, mesoscale approach that naturally models complex flows in a computationally efficient manner, but has thus far seen limited use for capturing such slurry (or similar) flows. Results from the model are presented for a wellbore cementing process with various annular configurations and cement slurry properties. In particular, the results consider irregularities and imperfections in the shape of the rock formation surface, as well as changes in the cement flow properties (e.g., viscosity), as could be affected by variations in mix and/or the pumping process. These results show an array of circumstances in which poor drilling mud displacement efficiency and bond strength development between the cement column and rock formation does or does not occur as the cement is pumped into the wellbore annulus. Lastly, potential future work and developments are discussed for the numerical approach to address other failure mechanisms of zonal isolation, which are still poorly understood mechanistically.
Real Time Prediction and Classification of Torque and Drag During Drilling Using Statistical Learning Methods
Authors: Hegde Chiranth , Wallace Scott , Gray Ken 
Published: October 2015

Abstract
A method for predicting torque and drag has been developed which is based on statistical learning models and which utilizes parameters routinely measured while drilling. Real time prediction of torque and drag during drilling has particular significance in on-the-fly rig floor operational modifications and in overall drilling optimization. These statistical methods are readily incorporated into real time drilling optimization procedures, first through a passive diagnostic tool, and subsequently through an integrated real-time control loop.
This paper presents statistical learning techniques such as bootstrapped regression, random forests, and support vector machines for prediction of downhole torque. An analysis of the aforementioned methods is carried out to evaluate computational efficiency of the processes. The statistical package R has been employed for processing and visualization of data and for displaying results. A comparison is made to real time ROP prediction carried out in previous work, to assess the relationship between predicted torque and ROP. A method is proposed to use classification techniques for predicting whether drilling is proceeding at the optimal level.
Torque values were accurately predicted with all three methods discussed in this paper. However, scalability of the methods must be considered, owing to the increased computational efficiency that is required. Computationally efficient and robust systems are of high priority for field applicability. To that end, ensemble techniques were analyzed along with the aforementioned methods and runtimes were evaluated for all of the methods employed. Results show that this method can be incorporated into real time drilling situations, with attending low runtimes. Development of more accurate methods will require additional computational power and the use of ensemble techniques. Classification proves to be a good technique whenever optimization is required, as indicated by real time predictions. Classification techniques illustrated in this paper explore the viability of various options for correcting undesirable drilling performance.
This paper presents state of the art statistical learning techniques for predicting torque and drag during drilling. Previous torque and drag calculations using finite element models provide a good cross reference with this statistical model for indicating operational anomalies. Unexpected values of torque may forecast imminent drilling problems. These methods can be utilized for prediction of drilling problems and proactive methods for avoiding them, and applied in optimized drilling procedures.
The Effect of Foam Rolling Duration on Hamstring Range of Motion
Authors: Couture Grace , Karlik Dustin , Glass Stephen C , Hatzel Brian M 
Published: October 2015

Musculoskeletal health benefits from flexibility training and maintaining a functional, or sport specific, range of motion is important to one’s overall fitness. Commercial foam rollers are commonly used in gyms, therapy clinics and homes, yet data are lacking on the optimal rolling duration and effect on range of motion.

Purpose :
The purpose of this study was to examine the effect of varied durations of a commercial foam roller treatment on hamstring range of motion.

Methods :
The knee extension range of motion of 33 college aged men and women (age= 20±1.5y, mass= 72.2±10.8 kg) was assessed after a short (2 sets of 10s) and long (4 sets of 30s) duration of hamstring self-administered myofascial release using a commercial foam roller. A one way ANOVA was performed to compare the mean knee extension angle for each condition to baseline measures.

Results :
Results indicated that neither the short duration (67.30 ± 10.60 deg) nor long duration (67.41 ± 10.81 deg) rolling condition produced significant increases in knee extension compared to baseline (67.70 ± 9.90 deg).

Conclusion :
Self-administered foam rolling for a total duration of up to 2 minutes is not adequate to induce improvements in knee joint flexibility. Contributing factors may include the amount of pressure imparted by the commercial roller as well as duration of treatment.
Comparison of Basal-Bolus and Premixed Insulin Regimens in Hospitalized Patients With Type 2 Diabetes
Authors: Bellido Virginia , Suarez Lorena , Rodriguez Maria Galiana , Sanchez Cecilia , Dieguez Marta , Riestra Maria , Casal Florentino , Delgado Elias , Menendez Edelmiro , Umpierrez Guillermo E. 
Published: October 2015

OBJECTIVE
Premixed insulin is a commonly prescribed formulation for the outpatient management of patients with type 2 diabetes. The safety and efficacy of premixed insulin formulations in the hospital setting is not known.

RESEARCH DESIGN AND METHODS
In a prospective, open-label trial, we randomized general medicine and surgery patients to receive a basal-bolus regimen with glargine once daily and glulisine before meals (n = 33) or premixed human insulin (30% regular insulin and 70% NPH insulin) twice daily (n = 39). Major outcomes included differences in daily blood glucose (BG) levels and frequency of hypoglycemic events (&lt;70 mg/dL) between treatment groups.

RESULTS
At the first prespecified interim analysis, the study was stopped early because of an increased frequency of hypoglycemia &gt;50% in patients treated with premixed human insulin. A total of 64% of patients treated with premixed insulin experienced one or more episodes of hypoglycemia compared with 24% in the basal-bolus group (P &lt; 0.001). There were no differences in mean daily BG level after the first day of insulin treatment (175 ± 32 vs. 179 ± 43 mg/dL, P = 0.64) between groups. A BG target between 80 and 180 mg/dL before meals was achieved in 55.9% of BG readings in the basal-bolus group and 54.3% of BG readings in the premixed insulin group (P = 0.23). There was no difference in the length of hospital stay or mortality between treatment groups.

CONCLUSIONS
Inpatient treatment with premixed human insulin resulted in similar glycemic control but in significantly higher frequency of hypoglycemia compared with treatment with basal-bolus insulin regimen in hospitalized patients with diabetes.
Depressive Symptoms in Youth With Type 1 or Type 2 Diabetes: Results of the Pediatric Diabetes Consortium Screening Assessment of Depression in Diabetes Study
Authors: Silverstein Janet , Cheng Peiyao , Ruedy Katrina J. , Kollman Craig , Beck Roy W. , Klingensmith Georgeanna J. , Wood Jamie R. , Willi Steven , Bacha Fida , Lee Joyce , Cengiz Eda , Redondo Maria J. , Tamborlane William V. ,   for the Pediatric Diabetes Consortium
Published: October 2015

OBJECTIVE
To evaluate the frequency of depressive symptoms and the diagnosis and management of depression in youth with type 1 diabetes (T1D) and type 2 diabetes (T2D) enrolled in the Pediatric Diabetes Consortium T1D and T2D registries.

RESEARCH DESIGN AND METHODS
The Children’s Depression Inventory (CDI) 2 Self-Report (Short) version was completed by 261 T1D and 339 T2D youth aged 10–17 years.

RESULTS
Symptoms of depression were identified in 13% of T1D and 22% of T2D (P = 0.007) participants; of these, only 4% of T1D and 9% of T2D youth were treated by a therapist within the prior 12 months. Depressive symptoms were associated with lower family income (P = 0.006) and obesity (P = 0.002) in T1D but not T2D youth.

CONCLUSIONS
Depressive symptoms are more frequent than diagnosed depression in youth with T1D or T2D. These results underscore the need for regular depression screening and appropriate referral for youth with diabetes.
Tissue engineering of the tympanic membrane using electrospun PEOT/PBT copolymer scaffolds
Authors: Danti Serena , Mota Carlos , D’alessandro Delfo , Trombi Luisa , Ricci Claudio , Redmond Sharon L. , De Vito Andrea , Pini Roberto , Dilley Rodney J. , Moroni Lorenzo , Berrettini Stefano 
Published: October 2015

Objective:
Tissue engineering has recently been identified as a suitable tool to develop replacements for the tympanic membrane. This study aimed at investigating PEOT/PBT copolymer scaffolds obtained via electrospinning as potential eardrum substitutes using an in vitro approach.

Study design:
PEOT/PBT copolymer ultrafine fibre meshes were manufactured and characterized for morphology and pore features. The scaffolds were cultured with human mesenchymal stromal cells (MSCs) under a dynamic flow regimen to improve cell infiltration and viability. The expression of basic extracellular matrix molecules was evaluated and compared to that of the human eardrum. Finally, the interaction between human tympanic membrane keratinocytes and the scaffolds was investigated.

Results:
The electrospun scaffolds had a fibre diameter of 1.9 ± 0.9 μm, thickness of 220 ± 56 μm, and porosity of 80% ± 0.8%. The macroporous meshes were suitable for cell infiltration, since 83.3% of relative void volume was from pores of 3–300-μm size. Over a four week culture, the bioreactor always increased the viability of human MSCs in the scaffolds with respect to traditional multi-well plate cultures. Viability was best at two weeks in culture, so this time-point was selected for further morphological and histochemical analyses. In static cultures, the human MSCs interacted with the top surface of the fibrous scaffold, while in dynamic cultures they infiltrated the mesh up to 240-μm depth. Adherent human MSCs maintained a non-differentiated phenotype, as shown by a very low production of glycosaminoglycans and glycoproteins, which are conversely highly expressed in the eardrum connective tissue layer. Human tympanic membrane keratinocytes adhered to the scaffold surface and were viable after 48 h.

Conclusion:
Using electrospinning combined with bioreactor culture appeared an efficient approach to develop biohybrid eardrum replacements in vitro, suitable for re-epithelialization in vivo.
Prevalence of Transmitted HIV-1 Drug Resistance among Young Adults Attending HIV Counselling and Testing Clinics in Kigali, Rwanda
Authors: Mutagoma Mwumvaneza , Ndahimana Jean d'Amour , Kayirangwa Eugenie , Dahourou Anicet G , Balisanga Helen , DeVos Joshua R , McAlister David , Yang Chunfu , Bertagnolio Silvia , Riedel David J , Nsanzimana Sabin 
Published: October 2015

Background Scaling-up antiretroviral therapy (ART) in resource-limited settings has raised concerns of emerging HIV drug resistance (DR) and its transmission to newly infected individuals. To assess the prevalence of transmitted drug resistance (TDR) in recently HIV-infected individuals, a WHO TDR threshold survey was conducted among young adults in Kigali, Rwanda. Methods Between May and July 2011, HIV subtype and genotyping were performed on dried blood spots (DBS) prepared from blood specimens collected from newly HIV-diagnosed and ART-naive individuals aged 15 to 21 years in eight HIV voluntary counselling and testing (VCT) sites in Kigali. Results In total, 57 of the 68 DBS collected from eligible participants were successfully amplified. The median age of participants was 20 years and 86% were female. Most participants (96%) were infected with subtype A1 virus. Two participants (4%) had the K103N non-nucleoside reverse transcriptase inhibitor (NNRTI) mutation and one (2%) had the M46L protease inhibitor (PI) mutation. The TDR prevalence was 3.5% (95% CI 0.4, 12.1) for NNRTI and 1.8% (95% CI 0.0, 9.4) for PI. Conclusions The prevalence of HIV TDR in VCT attendees in Kigali was characterized as low (<5%) for all drug classes according to the WHO HIV DR threshold survey methodology. Despite a decade of widespread ART in Rwanda, TDR prevalence remains low, and so the current first-line ART regimens should continue to be effective. However, as scale-up of ART continues, frequent HIV DR surveillance is needed to monitor the effectiveness of available ART regimens at the population level.
L’accueil des mineurs isolés étrangers : un défi face à de multiples paradoxes
Authors: Radjack Rahmethnissah , Hieron Sabrina , Woestelandt Laure , Moro Marie Rose 
Published: October 2015

L’administration définit les mineurs isolés étrangers comme des mineurs étrangers sans représentant légal en France. Souvent, ils fuient la guerre et la misère, tentent de rejoindre des lieux pour se reconstruire et vivre. Pour ceux qui parviennent à destination, les obstacles restent nombreux ; et la confrontation au réel de la migration, brutale. Nous présentons ici la situation de Merveille, jeune Congolais, pour illustrer l’impact des ruptures répétées dans l’accompagnement de ces jeunes, et abordons la question du recours au scolaire comme recours psychique possible. Si Merveille n’a pas subi de décompensation psychique, du fait de ses capacités de résilience, cela n’est pas le cas pour nombre de jeunes isolés étrangers. Nous faisons donc un point sur l’accès aux soins psychiques, et l’adaptation des professionnels souvent nécessaire face à cette clinique de l’errance.
Les mineurs isolés étrangers. De l’assignation paradoxale comme épreuve de professionnalité
Authors: Petrouchine Roman , Konaré Bintily , Zeroug-Vial Halima 
Published: October 2015

Le mineur isolé étranger est assigné, dans le cadre de sa conceptualisation comme de son accompagnement, au champ juridique. Or les paradigmes qui régissent sa prise en charge entrent en contradiction les uns avec les autres. Qui plus est, les jeunes et les professionnels sont pris dans une chronopolitique de l’urgence : la condition à l’obtention d’une régularisation est la réalisation en quelques mois de procédures à la complexité kafkaïenne. Enfin, la possibilité juridique récente d’opérer au déplacement des mineurs isolés étrangers d’un département à l’autre peut réactiver les angoisses de séparation des jeunes, quand les processus psychiques du jeune sont justement marqués du sceau du trauma. On observe une inadéquation des temporalités et des spatialités, subjective d’une part, institutionnelle d’autre part, ce qui constitue pour les accompagnants une épreuve de professionnalité particulière.
Freud à Thélème ou la psychanalyse appliquée au travail social avec des jeunes en grande difficulté
Authors: Blaquière Hélène , Katzarov Georgy 
Published: October 2015

Cet article aborde la question de l’application de la psychanalyse dans le champ du travail social à travers la description du fonctionnement de « Thélèmythe », une institution particulière, partenaire de l’Aide sociale à l’enfance, qui prend en charge des adolescents en difficulté. Il propose une esquisse de l’histoire de l’institution ainsi que quelques exemples du travail clinique qui peut s’y produire. La question théorique de fond étant : comment peut-on penser ou repenser la possibilité de l’aide sociale, appliquée notamment aux jeunes mineurs et jeunes majeurs, tout en faisant la part aux hypothèses freudiennes et à tout ce que la psychanalyse nous a appris dans la clinique de l’enfance, de l’adolescence et des psychoses ?