bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feasibility of a Method to Quantify Movement-Induced Conformational Changes in the Superficial Femoral and Popliteal (Femoropopliteal) Arterial Tree Using 3-D Angiography
Authors: Klein Andrew J. P. , Messenger John C. , Casserly Ivan P. , Hansgen Adam R. , Carroll John D. , Chen S.-Y. James 
Published: April 2009

Abstract
Endovascular revascularization of the superficial femoral and popliteal (femoropopliteal (FP)) artery is currently plagued by high rates of restenosis and stent fracture. One hypothesis behind these suboptimal clinical results implicates the unique physical forces that are applied to the FP segment during daily leg movement. In an effort to elucidate these forces, we applied angiography-based previously validated three-dimensional (3-D) modeling algorithms to angiograms of a FP artery in a patient with peripheral arterial disease. As the FP is the longest artery in the body, overlapping paired angiographic images of the entire FP artery were required. From these pair of two-dimensional angiographic views, individual 3-D FP segments can be generated. A validated fusion process was then performed in order to join these FP segments to form a complete 3-D FP artery. In order to investigate the effects of motion upon this arterial segment, we performed angiography and subsequent 3-D modeling of the FP artery in both the straight-leg (SL) and crossed-leg (CL) positions. In this paper, the methodology used to generate an in vivo FP artery model from sequentially acquired multiple angiographic images is reviewed. The data set from one patient in the SL and CL positions are used to demonstrate the 3-D modeling and fusion processes followed by the computation of various quantitative estimates in order to demonstrate the feasibility of this method. Inclusive in this technique is an assessment of the twist angle that is induced when the FP artery is moved from the SL to the CL position. The authors also submit the validation results for the method of calculating these twist angles as assessed on a metallic phantom and a computer-simulated arterial tree model.
Sensitivity of Hygrothermal Analysis to Uncertainty in Rain Data
Authors: Cornick Steve , Dalgliesh W. Alan , Maref Wahid 
Published: April 2009

Abstract
This paper describes a small study carried out using a hygrothermal simulation tool to investigate the sensitivity of wall performance results to uncertainty in the amount of rain impinging on the wall. Design standards for hygrothermal analysis of proposed designs include methods for selecting appropriate moisture reference years and specify the amount of water that is assumed to intrude into the wall. Weather data used as input for modeling purposes is generally assumed to be reliable, but recent work has shown that there may be considerable uncertainty in the rainfall data. A small study was carried out to investigate the effect of uncertainty of rainfall data on the hygrothermal performance of a typical residential building envelope. Most hygrothermal models require fully populated hourly datasets, which include rain data. Many locations, however, do not have this kind of data although many have qualitative rain data. Ten locations with rain gage data were chosen as typical of most regions of Canada, except for the far north. Different methods in estimating rainfall were considered as well as variations on the amount of rain data were subsequently made. Several performance criteria, including total moisture content and a mold index, were compared. Although the choice of which method for deriving quantities of water from qualitative codes does cause differences in the hygrothermal response and consequently the performance criteria, these differences appear to be manageable. It is suggested that practitioners should show their awareness of the probable level of uncertainty by stating error bands for their predictions of performance. It should be emphasized that the sources of uncertainty dealt with in this small study are not the only ones, but that they do focus on water entry through leakage paths. The natures of the leakage paths likely introduce greater uncertainty, and should also be borne in mind.
Evolution of Quench Factor Analysis: A Review
Authors: Kavalco Patricia Mariane , Canale Lauralice C. F. 
Published: April 2009

Abstract
One of the steps of the heat treatment process of age hardenable aluminum alloys is the quenching process in which the alloy is cooled from the solutionizing temperature. The objective is to quench sufficiently fast to avoid undesirable concentration of alloying elements in the defect and grain boundary structure, while at the same time not quenching faster than necessary to minimize residual stresses, which may lead to excessive distortion or cracking. Various studies have been conducted to predict the relative quench rate sensitivity to yield different properties for age-hardenable alloys. Of these different predictive methods, the one that showed the more realistic results is quench factor analysis since it involves a correlation of the cooling curve (time-temperature curve) of the cooling process throughout the quenching cycle for the desired cross-section size of interest with a C-curve (time-temperature-property curve) for the specific alloy of interest. The quench factor analysis numerical procedure has evolved since its original introduction. A review of the basic assumptions of the classical quench factor analysis model will be provided here which will include discussion of the various improvements to the classical model that have been proposed over the intervening years since its introduction.
Ein Adaptiver Regler zur Einstellung der Abzugsreinheiten von SMB-AnlagenAn Adaptive Controller to Regulate the Drain Purities of SMB-plants
Authors: Fütterer Marco 
Published: April 2009

Zusammenfassung
Die Simulated Moving Bed (SMB) Technologie ist ein bedeutender Trennprozess in der Verfahrenstechnik. Chromatographische Säulen werden zu einem Ring verschaltet und die Zu- und Abflüsse zyklisch so verändert, dass eine kontinuierliche Trennung eines binären Stoffgemisches möglich ist. Der Prozess reagiert empfindlich gegenüber Parameterunsicherheiten und Störungen in den Volumenströmen. Aus diesem Grund wird ein adaptiver Regler vorgeschlagen, welcher für die gewünschten Abzugsreinheiten die notwendigen Stellgrößen automatisch ermittelt. Dieser Regler basiert auf einem einfachen Modell für die Bewegung der Fußpunkte der Konzentrationsfronten und ist wegen seiner relativ einfachen Struktur speziell für den industriellen Einsatz geeignet.
Internal Model Control zur Regelung der Bandplanheit in KaltwalzwerkenInternal Model Control for Strip Flatness Control in Cold Rolling Mills
Authors: Jelali Mohieddine , Wolff Andreas , Sonnenschein Detlef 
Published: April 2009

Zusammenfassung
Die Bandplanheit stellt eines der wichtigsten Qualitätsmerkmale der gewalzten Erzeugnisse (Grobblech, Band und Folie), die in vielen Industriezweigen wie der Auto-mobil-, Bau-, Haushalts- und Verpackungsindustrie benötigt werden, dar. Beim betrachteten Walzprozess handelt es sich um ein totzeitbehaftetes und zum Teil stark gestörtes Mehrgrößensystem, was eine geeignete Regelungsstrategie erfordert. Dieser Beitrag berichtet erstmalig über die Entwurfsmethodik und Betriebsergebnisse beim Einsatz einer Internal-Model-Control(IMC)-Strategie zur Regelung der Bandplanheit in einer Kaltwalztandemstraße auf einem industriellen Prozessleitsystem. Eine orthogonale Polynomzerlegung des Planheitsfehlerprofils führt zu einer Dimensionsreduzierung und einer Entkopplung des Mehrgrößensystems. Störgrößenaufschaltungen sorgen für eine frühzeitige Kompensation der Wirkung von Störgrößen (Einlaufprofil- und Walzkraftschwankungen) in den vorderen Walzgerüsten. Die Anpassung der Reglerparameter an die sich verändernden Band- und Anlageneigenschaften erfolgt durch Gain-Scheduling.
Improved estimation for elliptically symmetric distributions with unknown block diagonal covariance matrix
Authors: Fourdrinier Dominique , Strawderman William E. , Wells Martin T. 
Published: April 2009

AbstractLetX, U1, …,Un-1benrandom vectors in ℝpwith joint density of the formf((X - θ)´∑-1(X - θ) +∑n-1j= 1U´j∑-1Uj) where bothθ∈ℝpand ∑ are unknown, the scale matrix ∑ being supposed structured as a diagonal matrix, that is, ∑= diag(∑1, …,∑b) where, for 1 ≤i≤b, ∑iis api×pimatrix and ∑i= 1bpi= p. We consider the problem of the estimation ofθwith the invariant loss(δ - θ)´∑-1(δ - θ)and propose estimators which dominate the usual estimatorδ0(X) = X. These domination results hold simultaneously for the entire class of such distributions. The proof uses a generalization of integration by parts formulae by Stein and Haff. We also consider estimating ∑ underLS(∑^,∑) =tr(∑^∑-1) - log |∑^∑-1| -pand propose estimators that dominate the unbiased estimator ∑^UB= diag(S1, …,Sb)/(n- 1), whereSi= ∑j= 1n- 1UijU´ijand dimUji=pi, for 1 ≤i≤band 1 ≤j≤n- 1. The subsequent development of expressions is analogous to the unbiased estimators of risk technique and, in fact, reduces to an unbiased estimator of risk in the normal case.
The HER-2 Receptor and Breast Cancer: Ten Years of Targeted Anti–HER-2 Therapy and Personalized Medicine
Authors: Ross Jeffrey S. , Slodkowska Elzbieta A. , Symmans W. Fraser , Pusztai Lajos , Ravdin Peter M. , Hortobagyi Gabriel N. 
Published: April 2009

Learning ObjectivesContrast the current strengths and limitations of the three main slide-based techniques (IHC, FISH, and CISH) currently in clinical use for testing breast cancer tissues for HER-2 status. Compare the efficacy of trastuzumab- and lapatinib-based regimens in the adjuvant and metastatic settings as reported in published clinical trials and regulatory approval databases. Contrast the list of biomarkers that have been associated with clinical resistance to trastuzumab and lapatinib and describe their current level of validation.This article is available for continuing medical education credit at CME.TheOncologist.com.
New Single Well Standalone Gas Lift Process Facilitates Barnett Shale Fracture Treatment Flowback
Authors: Elmer William G. , Elmer Stuart J. , Elmer Thomas E. 
Published: April 2009

Abstract
When performing multiple fracture treatments in horizontal Barnett Shale wells, many operators choose to utilize artificial lift to remove fracture fluids rather than incur the expense of energized fluids that may not be effective. Gas lift has been a popular artificial lift method to remove fracture fluids, as it allows for high liquid flowrates and is excellent at handling flowback sand. Its disadvantage is that a source of lift gas is required to initiate gas lift, with this source typically being other nearby gas wells or a third party gas pipeline. In new exploration areas such as the Barnett, often neither are available. Operators resort to costly nitrogen membrane units to provide lift gas, but are left with questions about the net gas being produced (since returning nitrogen and produced natural gas are combined downhole then vented to the atmosphere). A new system (patent pending) has been developed that addresses gas lift's issues of initially filling the system with lift gas, as well as maintaining this gas so that additional gas is not required. Being a closed loop system, it also provides for very accurate measurement of net gas production by measuring any gas in excess of that needed for lift, and discharging the same to a flare stack. The paper will describe the major components used in this system, present a case history, and address the significant cost reductions and other benefits realized.
Batch Pumping: A New Method To Solve Downhole Liquid Holdup
Authors: Elmer William G. 
Published: April 2009

Abstract
The premise that high annular velocities on rod pumped gas wells can cause liquid holdup in the casing is presented. A case is then made (using conventional vertical separator sizing equations) that the annular cross-sectional area is inadequate to allow gas-liquid separation to occur, preventing fluid from falling below the turbulent perforations to the pump intake. The concept of "Batch Pumping" is presented to industry as a simple, cost effective method to solve this separation problem for any well with this liquid holdup problem.
Challenges and Solutions to Running Tools Through Older Well Completions Containing Significant Paraffin and Asphaltene Buildup
Authors: Vaucher D. , Parrish C. , Brooks R. T. 
Published: April 2009

Abstract
Scarcity of petroleum supply is causing an industry emphasis on recompletions as well as drilling. This paper will address recompletion efforts in older wells, those drilled before 1998.
In such wells, buildup of asphaltenes and paraffins presents a challenge that causes significant losses of rig time, production and revenue both onshore and offshore.
A particularly difficult situation arises when trying to run tools through older completions’ tubing and casing in which significant buildup is found. Though not fully predictable, the composition and causes of these buildups have already been the subject of many industry publications. This paper uses case studies from fields located in and around the Gulf of Mexico to illustrate the difficulties of using modern tools on these older well completions.
Once the failure conditions under which each job was performed are established, it is shown that everything from malfunction of the equipment to not being able to run the equipment at all can be directly attributed to the presence of accumulated substances. Conversely, it is shown that the success of a job can at least in part be attributed to having produced a "clean" well condition in an older well prior to running the job.
These experiences in the field serve as a means to suggest the use of different types of tools to account for the presence or absence of buildup, as well as how tools can be run to depth when there is buildup in the well.
A New Integrated Model To Simulate the Disturbed Zone in CHOPS: Spread and Erosion
Authors: Du Zhimin , Jiang Wei , Chen Zhaohui 
Published: April 2009

Abstract
Permeability enhancement [1], which is due to the sand produced from disturbed zone around wellbore, is the key mechanisms to improve the oil production rate in CHOPS. This has lead to the demand for the accurate predicting methodology to the amount of sand production. In this paper, a new integrated spread-erosion numerical model was developed, in which sand is produced from disturbed zone, and its dynamic performance depends on the spreading of wormhole which is determined by the pressure gradient between wormhole tips and reservoir. Also sand is fallen off from sand wall which is depends on the erosion parameter. Mechanisms case study shows that sanding will continue for a while even when the spread of disturbed zone is pause, as sand wall erosion is another source of sanding. Compare with wormhole lab testing data and sanding well monitoring data, sanding dynamic performance which is simulated by this new model is more reasonable and more reliable.
Study of Sanding Mechanism and a New Model to Calculate the Sanding Critical Drawdown in Loosened Sandstone
Authors: Du Zhimin , Ma Lining , Wang Xiaolu , Chen Zhaohui 
Published: April 2009

Abstract
Sanding is a common phenomena during gas production in S gas reservoir due to the loosen sandstone formation, furthermore, the rock inner cohesion will be weaken by the water produced from interbed water and edge water, as the result, sand production in-situ is enhanced. Drawdown controlling is the reasonable strategy to sand control. To calculate the critical drawdown, a new model, which is based on the theory and lab testing data analysis to the rock composition, physical and chemical mechanism, cohesion weaken by watering, is developed in this paper. In this model, rock cohesion is considered as a function of mud content and changing with water saturation, which is a typical performance in the loose sand gas reservoir. It is more reasonable and reliable to forecast the sanding critical drawdown by this new model compare with field sanding monitoring data.
Novel Perforating Job Design Triples Well Productivity
Authors: Ibrahim Hanaey , Balushi Sameer , Salsman Alan , Nunez Alvaro Javier , Situmorange Haposan 
Published: April 2009

Abstract
Well productivity is driven by establishing a clean connection through the near wellbore zone of drilling and completion induced permeability impairment commonly referred to as the "near wellbore damaged zone". This connection through the damaged zone is most often achieved by perforating with explosive shaped charges. The effectiveness of this connection is the result of perforator selection criteria and the well environment in which the perforating job is executed.
In the depleted oil field under study a typical completion is perforated using large Tubing Conveyed (TCP) guns in "shoot and pull" mode in a static underbalance environment. After shooting the well is killed to allow the TCP guns to be pulled safely and the completion run. Production from the newly perforated intervals declines quickly due to near wellbore damage caused by the kill cycle.
The challenge in this case was to identify the proper perforating gun system, conveyance method and perforating program to achieve the optimal productivity once the well is put on production. Modeling software was utilized to predict the productivity ratio (PR) for different perforating systems considering gun size, charge type, shot density, reservoir parameters and the well conditions at the time of shooting.
The perforating program was modified to perforate the well with gas lift on in a flowing condition maintaining under balance conditions after shooting to assist with cleanup. The under balance at the time of shooting was managed using a permanent down hole gauge installed in the completion string.
The first well completed using this process showed improved production of greater than 3 times what was expected when compared to similar wells in the field.
This paper will cover the job design criteria, the job execution requirements and evaluation of the results. In addition, a summary of the study leading to this work and the total cost reduction details for the completion operations is also included.
The result of this novel perforating job design has led to a new completion strategy for oil fields in Oman thus improving overall well performance.
Pressure-Drop Predictions in Tubing in the Presence of Surfactants
Authors: Soni Sandip , Kelkar Mohan , Perez Ciro 
Published: April 2009

Abstract
Many marginal gas wells cannot sustain production without artificial lift. For deep gas wells, one of the most feasible techniques is to use foam lift — inject surfactant in the well and create stable foam to lift the liquid to the surface. Unfortunately, no correlation is available to calculate the pressure drop under foam flow conditions. Conventional pressure drop prediction models are unable to correctly predict the pressure drop under these conditions. In this paper, a new model is developed to predict the pressure drop under foam flow conditions. By using a simple drift flux model and using some of the available literature data on foam, a foam pressure drop model was developed, and compared with 570 data points collected from many gas wells. The match between the model and the actual observations is reasonable. The model can be further improved if additional data on the foam quality, stability and the ability to entrain liquids becomes available.
Pressure Transient Analysis of a Multiple-Wells System in a Circular Cylinder Reservoir
Authors: Lu Jing , Zhu Tao , Dinh Anh , Tiab Djebbar 
Published: April 2009

Abstract
Currently in the oil industry, a field usually contains several wells producing from the same drainage domain, and each well will have an effect on the pressure at other wells. For an infinite-acting multiple wells system, pressure transient analysis is already done by using superposition principle.
This paper presents pressure drawdown equations of a multiple wells system in a circular cylinder reservoir with constant pressure outer boundary. The proposed equations provide fast analytical tools to evaluate the performance of multiple wells, which are located arbitrarily in a circular cylinder reservoir, and are producing at different rates. This paper examines the pressure drawdown response of a specific well located in a system of producing wells. The interference effects of nearby producing wells on the pressure drawdown response are investigated. The proposed equations are illustrated by numerical examples.
It is concluded that, for a given multiple wells system in a circular cylinder reservoir, well pattern, well spacing, skin factor, flow rates and well off-center distances have significant effects on single well pressure transient behaviour. Because the reservoir is under edge water drive, the outer boundary is at constant pressure, when producing time is sufficiently long, steady-state is definitely reached.
Delineation of Application: Physical and Economic Optimization of Fractured Gas Wells
Authors: Marongiu-Porcu Matteo , Wang Xiuli , Economides Michael J. 
Published: April 2009

Abstract
Hydraulic fracturing is particularly suited for natural gas wells. For low permeability reservoirs the need is obvious: it is the only means to monetize a huge number of gas wells. In addition, in recent years horizontal wells with multiple transverse fractures have emerged as the configuration of choice for many low permeability or unconventional reservoirs such as shale gas.
However, because of increasing demand in the world economy, previously stranded gas of much higher permeability is rapidly becoming target for new field developments. Fracturing, which for similar-permeability oil reservoirs may be abandoned in favor of horizontal or complex well architecture, is a must for higher permeability gas wells because of considerably enhanced turbulence effects.
But turbulence in the fracture itself creates the need for design adjustments because of substantial reduction in the effective proppant-pack permeability.
We present a physical optimization scheme for fracturing natural gas wells and extend it to the fracturing of multiple treatments in horizontal wells. The latter, because of enhanced turbulence effects in the fracture, has an upper limit of application, about 0.5 md. For higher permeability, the multiple fractured horizontal well has an unacceptable reduction in well performance, and vertical wells with fractures are indicated instead.
In this paper, physical optimization is complemented by economic optimization by comparing vertical wells with and without fractures and horizontal wells with multiple fractures in a range of permeabilities. Of importance are the geographic location (e.g., North America vs international) and the markedly different costs associated with them. For lower permeability reservoirs, economic considerations that would make multiple fractured horizontal wells attractive in e.g., North America, render them uneconomic in many other parts of the world. This, along with the physical constraint outlined above, creates a narrow range of permeability where the configuration is applicable.