bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybrid Bits Offer Distinct Advantages in Selected Roller-Cone and PDC-Bit Applications
Authors: Pessier Rolf , Damschen Michael 
Published: March 2011

Summary
Early concepts of hybrid drill bits go back to the 1930s, but the development of a viable drilling tool has become feasible only with the recent advances in polycrystalline-diamond-compact (PDC) cutter technology. This paper describes a new generation of hybrid bits that is based on proven PDC-bit designs with rolling cutters on the periphery of the bit. Laboratory and field results will be presented that compare the performance of hybrid bits with that of conventional PDC and roller-cone bits. A hybrid bit can drill shale and other plastically behaving formations two to four times faster than a roller cone bit by being more aggressive and efficient. The penetration rate of a hybrid bit responds linearly to revolutions per minute (RPM) unlike that of roller-cone bits, which exhibit an exponential response with an exponent of less than unity. In other words, the hybrid bit will drill significantly faster than a comparable roller-cone bit in motor applications. Another benefit is the effect of the rolling cutters on the bit dynamics. Compared with conventional PDC bits, torsional oscillations are as much as 50% lower, and stick/slip is reduced at low RPM and whirl at high RPM. This gives the hybrid bit a wider operating window and greatly improves toolface control in directional drilling. The hybrid drill bit is a highly application-specific drill bit aimed at (1) traditional roller-cone applications that are rate-of-penetration (ROP) limited, (2) large-diameter PDC-bit and roller-cone-bit applications that are torque or weight-on-bit (WOB) limited, (3) highly interbedded formations where high torque fluctuations can cause premature failures and limit the mean operating torque, and (4) motor and/or directional applications where a higher ROP and better build rates and toolface control are desired.
The Influence of Salt Concentration in Injected Water on Low-Frequency Electrical-Heating-Assisted Bitumen Recovery
Authors: Bogdanov I.I.. I. , Torres J.A.. A. , Akhlaghi H.A.. A. , Kamp A.M.. M. 
Published: March 2011

Summary
Steam injection is often not a good alternative for oil recovery from shallow bitumen reservoirs. For instance, the thin caprock creates the danger of steam breakthrough. For deeper reservoirs, the heat losses from injection wells may be prohibitive. A technology that may be better suited is oil recovery aided by low-frequency electrical heating of the reservoir. This technology, well known for environmental remedial applications, has been field tried recently, yielding promising results. The process uses electric conductivity of connate water to propagate an alternating current between electrodes, inducing the Joule heating of the reservoir. An associated problem is the appearance of hot spots around the electrodes that may be relieved by water circulation. However, the water circulation may have a significant effect on the heating process because the electric conductivity of the circulated water depends on its salt content.
To find out the influence of salt concentration on process efficiency, we have studied the process of salt-water recirculation around an electrode using numerical simulation. The physical properties and operational data for Athabasca bitumen have been collected from the literature. The model built with Computer Modelling Group's STARS simulator and tested first with available analytical solutions has been validated, and the proper choice of the underlying grid and numerical tuning parameters has been verified. The process was also simulated at field scale for a common pattern of electrodes and production wells. The salt penetrated into the reservoir, far beyond the major water-circulation zone around the electrodes. This process increases the electric conductivity in a large region between electrodes, which improves the heating of the reservoir. The single-electrode simulation studies using different tools yielded similar results for a simple problem. More-complex (and more-realistic) field-scale simulations show that adding salt enhances the oil production. In practice, an upper concentration limit may be given by corrosion problems at the electrodes.
The reservoir simulation of bitumen recovery assisted by low-frequency heating is a challenging multiphysics problem. The understanding of the influence of salt concentration on the circulated water provided by this work is an important key in process-design considerations.
Deployment, Monitoring, and Optimization of a Scale Inhibitor and Associated Corrosion Inhibitor Within a Deepwater Subsea Facility Offshore Brazil
Authors: Jordan M.. , Linares-Samaniego S.. , Afonso M. Santos 
Published: March 2011

Summary
This paper presents field results and lessons learned from a floating production, storage, and offloading (FPSO) vessel, offshore Brazil where a scale and combination scale inhibitor (SI) and corrosion inhibitor (Cl) has been applied subsea to control both the deposition of scale and associated corrosion.
The paper outlines the problems encountered when the initial scale-inhibitor formulation was deployed in the field related to materials compatibility with the subsea manifold and the steps taken to develop and monitor an improved formulation. Problems that can affect product application in a subsea environment—including deposition of suspended solids within the chemical, hydrate formation, and incompatibility of the chemicals with umbilical material and produced fluid—will all be addressed. The laboratory methods used to select the product along with measurement methods used in the field are also discussed. The validation of the laboratory selection methods in the field required the development of a monitoring program to establish baseline control and to assess the degree of protection from scale deposition and corrosion across the process.
The use of novel real-time scale monitoring, as well as water-chemistry tracking, proved vital to understanding the efficiency of flow assurance within the processes and understanding how treatment rates of the scale inhibitor and corrosion inhibitor could be optimized.
This paper will outline in detail the particular issues associated with chemical injection to a subsea facility, many of which are currently being developed in the Gulf of Mexico, offshore West Africa, and offshore Brazil. This case study is a good example of lessons learned and sharing of best practices from another oil basin.
Improved Polymer-Flood Management Using Streamlines
Authors: Clemens Torsten , Abdev Joseph , Thiele Marco R. 
Published: March 2011

SummaryRecently, modern streamline (SL) simulation has been extended to polymer flooding. In this work, we extend the applicability of SL simulation further for efficient management of polymer-injection projects. We first present our method and then demonstrate the applicability of our approach using a Romanian field as an example. Owing to the price of polymers, an optimized injection strategy is crucial to minimize costs, maximize sweep, and thereby ensure profitability of a polymer flood. The biggest advantage of SL simulation in comparison to traditional finite-difference (FD) modeling is that polymer floods can be optimized on an individual-well-pattern basis. By being able to plot cumulative oil produced as a function of polymer injected for an individual well pattern, underperforming patterns—injectors and associated offset producers—can be indentified easily and rates, concentration, and slug size can be modified to improve the local efficiency of the flood. In this paper, we introduced a new metric—the polymer-injection efficiency as a function of time for each pattern—and we show how it is central to containing costs while improving oil recovery. We demonstrate our management method on a Romanian oil field that has been operating since 1961 with 21 injectors and 136 producers. We show that the utility factor (UF) (mass of polymers injected per volume of incremental oil produced) can be reduced while sustaining oil recovery. We conclude with a discussion on SL simulation as an enabling technology for reservoir-management decisions for polymer floods.
Numerical Investigation of Potential Injection Strategies To Reduce Shale Barrier Impacts on SAGD Process
Authors: Li Weiqiang , Mamora Daulat , Li Yamin , Qiu Fangda 
Published: March 2011

Summary
It is well known that shale barriers significantly reduce steam-assisted gravity drainage (SAGD) performance in Athabasca fields. An extensive 2D simulation study shows that the flow resistance at the end of shale barriers and the extra heat absorbed by the residual water inside the unproductive shale barrier are the main reasons for the shale barrier effects. Long continuous shale barriers located vertically above or near the wellbore delay production performance significantly.
We investigated potential strategies, including solvent coinjection, top injector application, or a combination of both, to reduce the shale barrier impacts. Solvent in the vapour phase can pass through the narrow flow path at the end of a shale barrier. Meanwhile, because the phase condenses from vapour to liquid, solvent efficiently reduces the flow resistance of the shale barrier. Liquid solvent coinjection can accelerate the near-wellbore flow and reduce the residual oil saturation at the wellbore vicinity. Coinjecting a multicomponent solvent can flush out the oil at different areas with different drainage mechanisms from vaporized and liquid components. Additional injector application at the top of the reservoir results in only marginal improvement.
Prediction of Frictional Pressure Gradient in Horizontal Oil/Water Dispersion Flow
Authors: Vielma Jany Carolina , Shoham Ovadia , Mohan Ram S. , Gomez Luis E. 
Published: March 2011

SummaryA novel model has been developed for the prediction of frictional pressure gradient in unstable turbulent oil/water dispersion flow in horizontal pipes. This model uses the friction-factor approach, based on the law of the wall, to predict the pressure gradient. Modification of both the von Karman coefficient κ' and the parameter B' have been carried out in the law of the wall to include the effect of the dispersed phase—namely, the dispersed-phase volume fraction and the characteristic-droplet-size diameters. The developed model applies to both dilute and dense flows, covering the entire range of water cuts. Model predictions have been compared with a comprehensive experimental database collected from literature, resulting in an absolute average error of 9.6%. Also, the comparisons demonstrate that the developed model properly represents the physical phenomena exhibited in unstable turbulent oil/water dispersions. These include drag reduction, increase in frictional pressure gradient with increasing dispersed-phase volume fraction, and the peak in the frictional pressure gradient at the oil/water phase-inversion region.
Optimum Utilization of Edge Pairs
Authors: Miller Karl A. , Xiao Yi 
Published: March 2011

Summary
Nearly all of Husky's SAGD projects in the Lloydminster, Saskatchewan area are in reservoirs with bottomwater. While operating several projects in this region, Husky observed that in some reservoir settings, the outer SAGD pair had significantly decreased performance compared to inner SAGD pairs. When the outer pair was shut in to improve overall pilot performance, the performance of the now exposed adjacent pair rapidly decreased.
It was hypothesized that operating the edge pairs protected inner pairs from the detrimental effects of bottomwater. Numerical simulation runs have confirmed this behaviour. The conclusions reached are that in many bottomwater settings, poorer-performing edge SAGD pairs protect and preserve the performance of inner SAGD pairs; and this should be taken into consideration during facilities' design, development of operational strategy, and production forecasting.
The Global Economic Crisis and Developing Countries: Effects, Responses and Options for Sustainable Recovery
Authors: Naudé Wim 
Published: March 2011

AbstractFollowing the financial crisis that broke in the U.S. and other Western economies in late 2008 and lead to a global economic crisis, there is now worldwide concern about its effect on the developing countries. One year into the crisis, this paper discusses its unfolding during 2008‐2009 and traces its effect on developing countries. The paper takes note of the greater resilience of man developing countries this time around (as opposed to previous global recessions) and discusses the global responses to the crisis during 2008 and 2009, concluding that the weak response of the rich world to help developing countries may contribute to a paradigm shift in international development.
Racial Disparities in Poverty Status among Families of Individuals with Spinal Cord Injury
Authors: Dismuke Clara E , Krause James S , Terza Joseph V 
Published: March 2011

AbstractBackground: Poverty rates among individuals with disabilities are much higher than for the general U.S. population. However, little is known about the likelihood of poverty among families of those with Spinal Cord Injury (SCI). Objectives: Examine the association of pre‐injury and post‐injury education with the likelihood of familial poverty by race/ethnicity for 1,405 adults between the ages of 18 and 64 who had a traumatic spinal cord injury at least one year prior to the study interview (2003). Methods: Based on reported household income in 2002, familial poverty status of individuals with a SCI was determined based on United States (U.S.) Federal Poverty Guidelines during the year of reported income. Based on a conceptual model of human capital loss and acquisition, a model of the likelihood of poverty was estimated separately for Non‐Hispanic White and Black/Hispanic families. Results: 18.33% of Non‐Hispanic White families and 42.35% of Black/Hispanic families with a member having SCI were found to be living below the poverty level. Bachelor's degree education attainment was the most important factor and was significantly associated with a lower likelihood of familial poverty for Non‐Hispanic White (‐0.10) and for Black/Hispanic families (‐0.27). Conclusions: We have proposed that the Social Security Administration grant presumptive disability eligibility for SCI, guarantee continued medical benefits after employment and pilot an online college degree reimbursement plan to reduce poverty among families of individuals with SCI.
The History and Politics of Health Care in America: From the Progressive Era to the Patient Protection and Affordable Care Act
Authors: Skidmore Max J. 
Published: March 2011

AbstractMax J. Skidmore surveys the history and politics of the development of health care delivery in the United States, and reviews Health Care Reform and American Politics: What Everyone Needs to Know, by Lawrence R. Jacobs and Theda Skocpol. This study, by two prominent scholars of health care in America, is a detailed analysis of the process that led to adoption of the Patient Protection and Affordable Care Act of 2010, and of the details of the Act.
In Response to Professor Dobelstein's Respectful Critique of A Tale of Three Commissions: The Good, the Bad, and the Ugly
Authors: Kingson Eric 
Published: March 2011

AbstractEric R. Kingson responds to Andrew Dobelstein's position with regard to “A Tale of Three Commissions: The Good, The Bad, and the Ugly,” which was published in Poverty & Public Policy Volume 2, Issue 3.
Poverty: Israel's Greatest Threat
Authors: Frankel Jackie 
Published: March 2011

AbstractJackie Frankel, a fund raising coordinator for the Jaffa Institute, a Non‐Profit Organization in the Tel Aviv‐Jaffa area of Israel, offers this op‐ed piece in which she asserts that poverty, and not the Israeli/Palestinian conflict, is the greatest threat to Israel and calls on that country's government to make sweeping changes in order to supplant these concerns.
Self-reported pain associated with the use of intermaxillary elastics compared to pain experienced after initial archwire placement
Authors: Tuncer Zeynep , Ozsoy Faik Serhat , Polat-Ozsoy Omur 
Published: March 2011

Abstract

Objective:
To evaluate the pain during the use of intermaxillary elastics and to compare it with that of initial archwire placement.

Materials and Methods:
Sixteen orthodontic patients who underwent initial bonding (7 girls, 13 boys; mean age 16.75 ± 2.61 years) and 19 patients who would be using intermaxillary elastics for the first time (13 girls, 7 boys; mean age 16.21 ± 3.01 years) were enrolled in this prospective study. A visual analog scale form was given to each patient to measure the pain levels, and these were measured by the same investigator using a digital caliper. Data were evaluated using Mann Whitney U-test.

Results:
The pain started to increase 2 hours after the application of elastics. The highest levels were achieved at the sixth hour and the same night. The pain levels started to decrease at day 2. Although the pain levels of the elastic group started to decrease after the second day, the pain levels of the initial bonding group were still significantly high.

Conclusions:
Intermaxillary elastics cause similar amounts of pain compared with initial archwire placement, but the pain of the elastics did not last as long as the pain felt after initial bonding.
Nasal obstruction causes a decrease in lip-closing force
Authors: Sabashi Kishio , Washino Kaei , Saitoh Issei , Yamasaki Youichi , Kawabata Atsushi , Mukai Yousuke , Kitai Noriyuki 
Published: March 2011

Abstract

Objective:
To investigate the relationship between nasal obstruction and lip-closing force.

Materials and Methods:
Nasal airway resistance and lip-closing force measures were recorded for 54 Japanese females. The subjects were classified into normal and nasal obstruction groups according to nasal airway resistance values. Differences between the normal and nasal obstruction groups in lip-closing force were tested statistically. Correlation coefficients were calculated between the measures for the normal and nasal obstruction groups.

Results:
Lip-closing force for the nasal obstruction group was significantly less than for the normal group (P &lt; .05). In the normal group, nasal airway resistance did not correlate with lip-closing force, while in the nasal obstruction group a significant negative correlation was found between nasal airway resistance and lip-closing force (P &lt; .05).

Conclusions:
Nasal obstruction is associated with a decrease in lip-closing force. When the severity of nasal obstruction reaches a certain level, the lip-closing force is weakened.
Central Endocannabinoid Signaling Regulates Hepatic Glucose Production and Systemic Lipolysis
Authors: O’Hare James D. , Zieliński Elizabeth , Cheng Bob , Scherer Thomas , Buettner Christoph 
Published: March 2011

OBJECTIVE
The endocannabinoid (EC) system has been implicated as an important regulator of energy homeostasis. In obesity and type 2 diabetes, EC tone is elevated in peripheral tissues including liver, muscle, fat, and also centrally, particularly in the hypothalamus. Cannabinoid receptor type 1 (CB1) blockade with the centrally and peripherally acting rimonabant induces weight loss and improves glucose homeostasis while also causing psychiatric adverse effects. The relative contributions of peripheral versus central EC signaling on glucose homeostasis remain to be elucidated. The aim of this study was to test whether the central EC system regulates systemic glucose fluxes.

RESEARCH DESIGN AND METHODS
We determined glucose and lipid fluxes in male Sprague-Dawley rats during intracerebroventricular infusions of either WIN55,212-2 (WIN) or arachidonoyl-2'-chloroethylamide (ACEA) while controlling circulating insulin and glucose levels through hyperinsulinemic, euglycemic clamp studies. Conversely, we fed rats a high-fat diet for 3 days and then blocked central EC signaling with an intracerebroventricular infusion of rimonabant while assessing glucose fluxes during a clamp.

RESULTS
Central CB1 activation is sufficient to impair glucose homeostasis. Either WIN or ACEA infusions acutely impaired insulin action in both liver and adipose tissue. Conversely, in a model of overfeeding-induced insulin resistance, CB1 antagonism restored hepatic insulin sensitivity.

CONCLUSIONS
Thus central EC tone plays an important role in regulating hepatic and adipose tissue insulin action. These results indicate that peripherally restricted CB1 antagonists, which may lack psychiatric side effects, are also likely to be less effective than brain-permeable CB1 antagonists in ameliorating insulin resistance.
Glucose- and Hormone-Induced cAMP Oscillations in α- and β-Cells Within Intact Pancreatic Islets
Authors: Tian Geng , Sandler Stellan , Gylfe Erik , Tengholm Anders 
Published: March 2011

OBJECTIVE
cAMP is a critical messenger for insulin and glucagon secretion from pancreatic β- and α-cells, respectively. Dispersed β-cells show cAMP oscillations, but the signaling kinetics in cells within intact islets of Langerhans is unknown.

RESEARCH DESIGN AND METHODS
The subplasma-membrane cAMP concentration ([cAMP]pm) was recorded in α- and β-cells in the mantle of intact mouse pancreatic islets using total internal reflection microscopy and a fluorescent translocation biosensor. Cell identification was based on the opposite effects of adrenaline on cAMP in α- and β-cells.

RESULTS
In islets exposed to 3 mmol/L glucose, [cAMP]pm was low and stable. Glucagon and glucagon-like peptide-1(7-36)-amide (GLP-1) induced dose-dependent elevation of [cAMP]pm, often with oscillations synchronized among β-cells. Whereas glucagon also induced [cAMP]pm oscillations in most α-cells, &lt;20% of the α-cells responded to GLP-1. Elevation of the glucose concentration to 11–30 mmol/L in the absence of hormones induced slow [cAMP]pm oscillations in both α- and β-cells. These cAMP oscillations were coordinated with those of the cytoplasmic Ca2+ concentration ([Ca2+]i) in the β-cells but not caused by the changes in [Ca2+]i. The transmembrane adenylyl cyclase (AC) inhibitor 2′5′-dideoxyadenosine suppressed the glucose- and hormone-induced [cAMP]pm elevations, whereas the preferential inhibitors of soluble AC, KH7, and 1,3,5(10)-estratrien-2,3,17-β-triol perturbed cell metabolism and lacked effect, respectively.

CONCLUSIONS
Oscillatory [cAMP]pm signaling in secretagogue-stimulated β-cells is maintained within intact islets and depends on transmembrane AC activity. The discovery of glucose- and glucagon-induced [cAMP]pm oscillations in α-cells indicates the involvement of cAMP in the regulation of pulsatile glucagon secretion.