bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pickling Well Tubulars Using Coiled Tubing: Mathematical Modeling and Field Application
Authors: Al-Mutairi S. H. , Hill A. D. , Nasr-El-Din H. A. 
Published: December 2007

Summary
Coiled tubing is usually used to conduct acid pickle treatments. The purpose of the treatment is to prevent pumping damaging materials into the formation before the main acid job. In this case, the acid is pumped down the coiled tubing, and then flowed up through the tubing-coiled tubing annulus. Pickling is a process of flow with heterogeneous reactions occurring with mill scale (Fe3O4) and other contaminants at both the inner wall of the production tubing and the outer surface of the coiled tubing.
Pickling is an essential part of well stimulation treatments if the main treatment fluids (e.g., acidizing, fracturing, and gravel packing) if the main treatment fluids are to be bullheaded. However, it appears that traditional pickle practices are overestimating the required acid volume and/or concentration. Field data indicate that excessive acid volumes are used for tubing pickle because large returns of unreacted acid are usually recovered on the surface.
In this paper, mechanisms to explain the behavior of acid contact with the tubing are presented, and a model for predicting acid consumption and dissolution of tubular contaminants is developed. The model includes reactions of acid with mill scale. A system of nonlinear, partial differential equations is developed, and the equations are solved numerically to predict the concentrations of major species as a function of axial position along the tubing and in the effluent from the well during flowback.
Field application included pickling of low-carbon steel tubing (11,900 ft of 5.5-in. C-95) using coiled tubing. A slug of 5,000 gals of 20 wt% HCl with additives was used. Samples were collected from the treated well during the flowback of the pickling treatment. The model was used to predict the concentrations of various species in the well flowback samples. Model predictions for acid, chloride ion, and total iron concentrations were in agreement with field results. In addition, the model proved to be a valuable tool in optimizing future pickling treatments.
Downhole Pressure Boosting in Natural Gas Wells: Well Candidate Selection and Project Progress
Authors: Liley J. E. N. , Oakley S. D. 
Published: December 2007

Summary
In recent years, gas exploration and production (E&P) companies have acknowledged that pressure boosting in close proximity to a reservoir can accelerate production rates as well as increase the recovery of reserves beyond that possible by conventional central compression alone. This paper summarizes the key well and reservoir parameters that determine the production enhancement potential of downhole gas compression (DGC).
An industry-funded joint industry project (JIP) has been established to complete the development of this key enabling technology. Detailed design is well under way, with the objective of completing a field trial in 2007. A summary of progress to date on this project is included in this paper.
New Frac-Pack Redesign Methodology Improves Estimation of Tip Screenout Post-FET
Authors: Edwards W. J. , Gauthier S. , Clarkson B. 
Published: December 2007

Summary
When the first frac pack was performed in the Gulf of Mexico (GOM) over a decade ago, very little was known about the effects this form of sand control would have on the intended formation. Even less was known about how to optimize the treatment to obtain the most benefit for the formation. Since that time, the sand control community has learned a great deal about the effects and benefits of frac-packing various unconsolidated formations throughout the world. However, most of the knowledge and design criteria have remained housed within the minds of individuals and cannot be looked at as a whole to find trends and fine-tune the design methods currently being used. Another complicating factor is the number of frac models of varying degrees of complexity being used within the industry. Therefore, even though thousands of frac packs have been performed globally, frac-pack redesign methods are still subjective and differ from individual to individual and from model to model.
The recent creation of a database that houses selected formation evaluation test (FET) and frac data along with model-specific parameters allows full-scale analysis of a large number of jobs pumped in the Gulf of Mexico (GOM). With a consistent analysis procedure in place, the database, populated with numerous treatments by engineers working throughout the GOM, can be analyzed objectively. The data contained in this database include rock mechanics, net pressures, pumping trend data, tip screenout (TSO) times, and other variables.
This paper explains the methodology and discusses the results of the database analysis, using case studies to determine the best method for analysis of the jobs. Crossplots show the correlation between TSO prediction and actual events and suggest recommendations for more successful design work in the future. This paper is meant to give up-to-date guidelines for designing better frac packs.
Rigless Interventions in Failed Gravel-Pack Gas Wells Using New Resin Systems
Authors: Lightford S. C. , Pitoni E. , Emiliani C. N. , Devia F. , Valli V. 
Published: December 2007

SummaryWhen a gravel-pack completion fails, it usually results in loss of production for the interval until a workover rig is available to recomplete the well. This paper describes two recent successful rigless interventions completed in offshore multizone completed gas wells in the Adriatic Sea. A key factor in the success of these remedial treatments has been the application of two different chemical technologies applied to the proppant while it is being pumped into the well.In the first well, production loss was caused by fines migration (fine silt ≤44 microns) into the 40/60 gravel-pack sand, which completely plugged the screens and gravel. An intervention was performed which included sealing the existing completion and then reperforating the premium screen using wireline guns. The interval was then fractured with a tip screenout design and a through-tubing screen was placed across the perforated screen. Critical to this treatment was the use of a surface modifying agent to prevent fines migration and plugging of the gravel pack. Production results have confirmed the correctness of this technical choice.A different problem existed with the second well, which had a frac-pack completion; in this case, a screen failure resulted in formation sand and proppant being produced to the surface. The well was refractured through the hole in the screen and a newly developed resin was applied to the proppant to lock the proppant into place and thus repair the damaged screen without restricting the flow area with a secondary inner string. Unlike conventional resin-coated proppant at low temperatures, this new type of resin does not require confinement pressure and/or the use of chemical flushes to cause the resin to set. Since the intervention, the well has been producing sand-free at very close to the original productivity index (PI).In both cases, these treatments have put back into production wells that in the past could not have been restored to production except through recompletion using a workover rig. This paper will describe the treatment design, well operations performed, materials used, and production performance of each well, comparing each aspect with the case of a conventional recompleted well.
Thrombospondin-1 Is an Adipokine Associated With Obesity, Adipose Inflammation, and Insulin Resistance
Authors: Varma Vijayalakshmi , Yao-Borengasser Aiwei , Bodles Angela M. , Rasouli Neda , Phanavanh Bounleut , Nolen Greg T. , Kern Emily M. , Nagarajan Radhakrishnan , Spencer Horace J. , Lee Mi-Jeong , Fried Susan K. , McGehee Robert E. , Peterson Charlotte A. , Kern Philip A. 
Published: December 2007

OBJECTIVE—We examined the relationship between the expression of thrombospondin (TSP)1, an antiangiogenic factor and regulator of transforming growth factor-β activity, obesity, adipose inflammation, and insulin resistance.
RESEARCH DESIGN AND METHODS—TSP1 gene expression was quantified in subcutaneous adipose tissue (SAT) of 86 nondiabetic subjects covering a wide range of BMI and insulin sensitivity, from visceral adipose (VAT) and SAT from 14 surgical patients and from 38 subjects with impaired glucose tolerance randomized to receive either pioglitazone or metformin for 10 weeks. An adipocyte culture system was also used to assess the effects of pioglitazone and coculture with macrophages on TSP1 gene expression.
RESULTS—TSP1 mRNA was significantly associated with obesity (BMI) and insulin resistance (low insulin sensitivity index). Relatively strong positive associations were seen with markers of inflammation, including CD68, macrophage chemoattractant protein-1, and plasminogen activator inhibitor (PAI)-1 mRNA (r ≥ 0.46, P = 0.001 for each), that remained significant after controlling for BMI and Si. However, TSP1 mRNA was preferentially expressed in adipocyte fraction, whereas inflammatory markers predominated in stromal vascular fraction. Coculture of adipocytes and macrophages augmented TSP1 gene expression and secretion from both cell types. Pioglitazone (not metformin) treatment resulted in a 54% decrease (P &lt; 0.04) in adipose TSP gene expression, as did in vitro pioglitazone treatment of adipocytes.
CONCLUSIONS—TSP1 is a true adipokine that is highly expressed in obese, insulin-resistant subjects; is highly correlated with adipose inflammation; and is decreased by pioglitazone. TSP1 is an important link between adipocytes and macrophage-driven adipose tissue inflammation and may mediate the elevation of PAI-1 that promotes a prothrombotic state.
Fractals
Authors: Mendivil F. 
Published: December 2007

AbstractWe introduce a fractal as a mathematical object that has strong scaling behavior. That is, its “behavior” at one scale is strongly related to its “behavior” at finer scales. We give examples of many different types of geometric fractals and then introduce other types of fractal objects, like fractal functions or fractal random processes. These fractals can have exact scaling, approximate scaling, or only statistical scaling behavior. A particularly nice class of fractals are those defined by the iterated function system (IFS). We give an application of IFS fractals to image representation and close with some brief comments on a relationship between fractals and wavelets.
Linear and Nonlinear Programming
Authors: Solow Daniel 
Published: December 2007

Abstract
Linear programs (LPs) and nonlinear programs (NLPs) are mathematical problems in which data are used to find the values of variables that minimize or maximize an objective function while simultaneously satisfying several imposed constraints on the values of the variables. Such problems arise frequently in computer science, mathematics, business, economics, statistics, engineering, operations research, and the sciences. An overview of the similarities and differences between LPs and NLPs is presented here. For example, although the art of building LP and NLP models involves identifying the variables, objective function, and constraints, methods for solving such problems differ greatly. A finite procedure has been developed to solve all LPs; however, no such procedure is available for solving NLPs.
Pattern Recognition
Authors: Schalkoff Robert J. 
Published: December 2007

Abstract
Pattern recognition (PR) concerns the description or classification (recognition) of measurements. PR capability is often a prerequisite for intelligent behavior. PR is not one technique, but rather a broad body of often loosely related knowledge and techniques. PR may be characterized as an information reduction, information mapping, or information labeling process. Historically, the two major approaches to pattern recognition are statistical (or decision theoretic), hereafter denoted StatPR, and syntactic (or structural), hereafter denoted SyntPR. The technology of artificial neural networks has provided another alternative, neural pattern recognition, hereafter denoted NeurPR. NeurPR is especially well suited for “black box” implementation of PR algorithms. As no single technology is always the optimal solution for a given PR problem, all three are often considered in the quest for a solution.
Probability and Statistics
Authors: Johnson James 
Published: December 2007

Abstract
After a brief historical account of probability's evolution over the past five centuries, the article presents techinical overviews of concepts that are central to computer science and engineering applications. These areas are probability spaces, combinatorics, random variables and their distributions, convergence modes, computer simulations, and statistical inference. Each section begins with elementary definitions, continues with the most frequently used techniques and theorems, and concludes with more advanced results. Examples and typical computations accompany the presentations.
Shared Memory Multiprocessors
Authors: Zhang Li , Parashar Manish 
Published: December 2007

Abstract
Shared memory multiprocessors are multiprocessor systems that logically implement a single global address space. The model for parallel programming based on such systems, the shared address space model, is straightforward and frees programmers from the tedious and sometimes complicated task of orchestrating all communication and snychronization through explicit message passing to access remote data. As a result, this class of multiprocessor systems has received much commercial as well as research interest.
Software Product Certification
Authors: Voas Jeffrey 
Published: December 2007

Abstract

Here, we examine the process and challenges of certifying software‐intensive systems. We will first review the interpretation of the term,
certification
. We then review different types of certification processes, and discuss challenges to forming software certification procedures. And finally, we discuss a strategy for gaining the maximum benefit from performing certification by formulating the correct procedures that are needed to roll out a certification plan by recommending appropriate guidelines to those developers whose products will be judged.
Data Privacy
Authors: Beresford Alastair , Scott David 
Published: December 2007

AbstractData arepersonally identifiableif they can be attributed to a particular individual. Therefore,data privacyis concerned with the protection of personally identifiable information that, if unconditionally published, would violate an individual's privacy. For example, the right to solitude is violated if surveillance cameras peer into homes and are used to monitor the activities of occupants. An individual's right to secrecy is broken if personal health or financial data are made public. The right to anonymity is jeopardized by a system requiring all shop customers to provide identity documents when making purchases.
Behavioral Sciences and Computing
Authors: Barnhart Steven M. , Lisi Richard De 
Published: December 2007

Abstract
This article presents an overview of behavioral science research on human–computer interactions. The research is peresented according to the following three categories: (1) antecedent‐consequence effects, (2) model building, and (3) individual‐social perspectives. The first category, antecedent‐consequent effects, asks questions such as follows: How does variability in human abilities, traits, and prior performance affect computer use? How does use of computers affect variability in human abilities, traits, and subsequent performance? The second category, model building, consists of research on the nature of human abilities and performance using metaphors form computer science and related fields. Here, the behavioral scientist is primarily interested in understanding the nature of human beings but uses computer metaphors as a basis for describing and explaining human behavior. Model building can also start with assumptions about the nature of human beings, for example, limitations of human attention or types of motivation that serve as the basis for the development of new products and applications for human use. The third category, individual‐social perspective, investigates the effects of increased access to and acceptance of computers in everyday life on human social relations. Questions addressed here are those such as follows: Do computers serve to isolate or connect persons to one another? What are the implications of lack of either access or acceptance of computers in modern cultures? Given the sheer quantity of empirical invesigations in behavioral sciences computing research, the reader should appreciate the highly selective nature of this article.
Non‐Inferiority Trial
Authors: Hung H. M. James , Wang Sue‐Jane , O'Neill Robert 
Published: December 2007

Abstract
Noninferiority trials employ a selected active‐control treatment, the effect of which has been established in historical placebo‐controlled trials. The active control serves as a comparator for evaluating the effect of an experimental treatment. A placebo arm may be either present in or absent from the noninferiority trial, depending on whether use of the placebo arm is feasible. In contrast with showing superiority, it is much more challenging to design a “show noninferiority” trial. The notion of noninferiority is extremely difficult to define, and a threshold termed “noninferiority margin” must be determined to define the noninferiority hypothesis for testing. The margin determination depends on many key factors: the objective of the noninferiority trial, critical assumptions pertaining to the ability of a trial to distinguish between an effective and an ineffective treatments, and the applicability of the historical estimate of the active control's effect to the noninferiority trial when the placebo cannot be used, and so forth. This article is intended to pinpoint the factors critically needing consideration for the viability of using a noninferiority trial to evaluate the effect of an experimental treatment.
Multistage Genetic Association Studies
Authors: Thomas Duncan , Conti David 
Published: December 2007

Abstract
The practice of individualized medicine for therapy or prevention could be informed by studies of genetic modifiers of treatment effects. This special case of gene–environment interaction studies offers several unique opportunities by exploiting random assignment of treatments. Two basic approaches are possible, one based on genetic studies added to a preexisting randomized controlled trial, the other based on targeted intervention studies added to a preexisting genetic cohort study. We focus in particular on multistage sampling designs that exploit the prior information from the parent study to improve the statistical efficiency of the study of genetic modifiers of treatment effects. In particular, we discuss different contexts in which either design might be used—a study of a single candidate gene, an entire pathway, or a genome‐wide association scan.
Minimum Effective Dose (MinED)
Authors: Thomas Neal , Ting Naitee 
Published: December 2007

AbstractThe minimum effective dose (MinED or MED) defines a lower bound for therapeutically useful doses. The MinED is important because most drugs have increasing potential for safety problems as dose is increased. The MinED is typically studied during phase II of drug development. A concise definition of the MinED from the International Conference on Harmonization (ICH) guidelines is “the smallest dose with a discernible useful effect.” We discuss methods to give operational meaning to the descriptors “useful” and “discernible.”
Cooperative North Scandinavian Enalapril Survival Study (
CONSENSUS
)
Authors: Snapinn Steven M. 
Published: December 2007

Abstract

The Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS) was a landmark trial that demonstrated a large and highly significant reduction in mortality with the angiotensin‐converting enzyme inhibitor, enalapril, in patients with severe heart failure. Although the study was designed to enroll 400 patients, CONSENSUS terminated with only 253 patients due to a recommendation from the ethics review committee. The overall mortality rates were 68 of 126 placebo patients (54%) and 50 of 127 enalapril patients (39%);
P
= 0.003. Additional analyses suggested that the effect of enalapril on mortality is related to hormonal activation, particularly to activation of the renin‐angiotensin system. Surviving CONSENSUS patients were followed for an additional 10 years after termination of the trial, at which time five patients remained alive, all from the enalapril group.
Therapeutic Index
Authors: Abughazaleh Raed D. , Tracy Timothy S. 
Published: December 2007

AbstractTherapeutic index is an expression of the relative toxicity as compared to efficacy of a given compound. In animal studies, it can be computed as the ratio of the median lethal dose (LD50) to the median effective dose (ED50). In humans, it is frequently expressed as the ratio of the median toxic dose (TD50) to the ED50. Several issues limit the utility of the therapeutic index, and to‐date there remains no official list of drugs considered to possess narrow therapeutic indices. Mortality is a poor measure of a drug's toxicity and raises ethical concerns in animal studies. Similarly, ED50can be a poor measure of a drug's effectiveness because of lack of consistency in endpoint biomarkers and because the ED50may be different for multiple conditions the drug may be used to treat. When LD50and ED50are obtained in animals, any extrapolation to humans is limited. In addition, multiple factors of interindividual and intraindividual variability exist in humans and can limit the utility of a therapeutic index estimate. Interindividual variability can be caused by either pharmacokinetic or pharmacodynamic differences, and may play an important role in brand‐to‐generic switching of narrow therapeutic index drugs. Intraindividual variability can also be related to physiologic factors that affect absorption, distribution, metabolism, or excretion of a drug. In conclusion, use of a therapeutic index requires an understanding of its limitations, and may be most useful in the preclinical stages of drug testing where limited experience of the drug's administration is available. To date, there remains no official guidance to research laboratories and pharmaceutical companies on the optimal use of therapeutic index.
Optimal Biological Dose for Molecularly‐Targeted Therapies
Authors: Ahn Chul , Kang Seung‐Ho , Xie Yang 
Published: December 2007

Abstract
Phase I cancer clinical trials are small dose‐finding studies designed to rapidly identify the optimal dose of a new anticancer agent. The optimal dose has been defined as the maximum tolerated dose (MTD) for conventional cytotoxic anticancer drugs, and this dose is typically recommended as the phase II dose. In the past decade, a new approach for cancer treatment has emerged. This new approach, now widely referred to as “molecularly targeted therapy” is designed a priori, based on the knowledge of various physiological molecules that have been obtained by the development of molecular biology. Most molecularly targeted agents slow or stop the growth of tumors. Such agents are, in general, less toxic than conventional cytotoxic agents; as a result, the maximum therapeutic effect may occur at doses well below the MTD. With the emergence of a growing number of molecularly targeted agents, approaches to early drug development are changing. We present dose‐finding designs for phase I clinical trials of molecularly targeted drugs. There is an increasing need to develop designs to find the optimal biological dose for molecularly targeted agents, and the utility of designs needs to be prospectively evaluated in future clinical dose‐finding trials for a variety of molecularly targeted agents.