bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increase in horizontal stress induced by preloading
Authors: Stamatopoulos C. , Petridis P. , Bassanou M. , Stamatopoulos A. 
Published: November 2009

In this paper, the results of an elaborate field preloading study are presented. In addition to conventional geotechnical studies prior to and after preloading, and measurement of settlements at some locations during the preloading process, the field study includes measurements of vertical stresses just below the embankment and horizontal stresses at different depths during the preloading process. Of particular interest is the measured increase in horizontal stresses induced by preloading, as this factor affects the dynamic soil response and the liquefaction resistance. Elasto-plastic and simplified methods were used to predict soil improvement and compare it with measurements. The measurements and the numerical methods illustrated (a) the increase in horizontal stress induced by preloading, and (b) the accuracy of different methods to predict soil response, including this increase. Dans cet exposé, nous présentons les résultats d'une étude complexe sur la pré-charge de terrain. Outre les études géotechniques conventionnelles réalisées avant et aprés la pré-charge, et le mesurage des tassements dans certains endroits pendant le processus de pré-charge, l'étude de terrain comprend le mesurage des contraintes verticales juste en dessous du talus ainsi que des contraintes horizontales á différentes profondeurs pendant le processus de pré-charge. L´augmentation mesurée des contraintes horizontales causées par la pré-charge est particuliÈrement intéressante, car ce facteur affecte la réponse dynamique du sol et la résistance á la liquéfaction. Nous avons utilisé des méthodes simplifiées et élasto-plastiques pour prédire l'amélioration du sol et la comparer avec les mesures. Les mesurages et les mé thodes numé riques ont illustré (a) l'augmentation de la contrainte horizontale causée par la pré-charge et (b) l'exactitude des différentes mé thodes permettant de prédire la ré ponse du sol, notamment cette augmentation.
A complementary field study on the uniformity of lime-cement columns for deep mixing
Authors: Larsson S. , Dahlström M. , Nilsson B. 
Published: November 2009

This paper presents results from work concerning development of the installation technique of lime-cement columns for ground improvement by deep mixing, as a part of the work of the Swedish Deep Stabilization Research Centre. A second field test was performed in order to test the findings from a previous work published by Larsson et al. The same methodology was adopted as in the previous work. However, the experimental programme was somewhat modified. Statistical analysis of variances, ANOVA, was used to investigate the influence of a number of factors in the mixing process: retrieval rate; number of mixing blades; rotation speed; air pressure in the binder tank; and diameter of the binder outlet hole. The analysis was performed with respect to the stabilisation effect and the coefficient of variation evaluated from hand-operated penetrometer tests on excavated column sections in open test pits. The retrieval rate and the number of mixing blades were found to have a significant effect. The effect of rotation speed, the binder tank air pressure, and the diameter of the outlet hole were insignificant. The two field studies illustrate the importance of performing a sufficient number of tests when studying influencing factors, because the strength is highly stochastic with large variations. Cet exposé présente les résultats de travaux concernant le développement de l'installation technique de colonnes de chaux-ciment pour améliorer le sol par mixage profond, dans le cadre des travaux du Centre de recherche sur la stabilisation profonde en Suède. Nous avons réalisé un second essai sur le terrain afin de tester les résultats d'une é tude précédente publiée par Larsson et al. Nous avons adopté la même méthodologie que dans les travaux précédents. Cependant, nous avons quelque peu modifié le programme expérimental. L'analyse statistique des variantes, ANOVA, a é té utilisée pour enquêter sur l'influence d'un certain nombre de facteurs dans le processus de mixage: taux de récupération, nombre de lames de mixage, vitesse de rotation, pression de l'air dans le réservoir d'agent liant et diamètre du trou de sortie de l'agent liant. L'analyse a é té faite relativement à l'effet de stabilisation et au coefficient de variation é valués à partir d'essais au pénétromètre manuel sur des sections de colonnes excavées dans des fosses d'essai ouvertes. Nous avons trouvé que le taux de récupération et le nombre de lames de mixage avaient un effet significatif. La vitesse de rotation, la pression d'air dans le réservoir de l'agent liant et le diamètre du trou de sortie n'avaient pas d'effet. Les deux é tudes sur le terrain montrent combien il est important de réaliser un nombre suffisant d'essais pour l'étude des facteurs influents, car la résistance est hautement stochastique avec de grandes variations.
Reinforced lime columns: a new technique for heave control
Authors: Hewayde E. , El Naggar H. , Khorshid N. 
Published: November 2009

Excessive volume changes of expansive soil cause severe damage to civil structures, which costs billions of dollars in annual repairs. In this paper, the optimum ratio of lime to soil weight to maximise the efficiency of lime columns as a technique to reduce the swelling of expansive soil is investigated. A new technique to further enhance the efficiency of the lime columns technique in reducing soil swelling is also investigated, namely reinforced lime columns. The new technique involves reinforcing the lime columns using reinforcement bars attached to the foundation of the structure. The experimental study involved laboratory-scale tests of expansive soil beds treated with lime columns supporting model foundations. The experimental results showed that the optimum lime content is 6% (by weight) of the soil within the column. It was found that the lime columns technique minimised the swelling of the expansive soil by 33%. In the meantime, the reinforced lime columns reduced the swelling of an identical soil bed by 69%. The results also showed that the swelling of the expansive soil decreased with an increase in the ratio Lcol/Dsoil (the ratio of the length of lime columns to the depth of expansive soil). Des changements de volume excessifs dans les sols expansifs endommagent gravement les structures civiles, ce qui entraŷne des réparations annuelles se chiffrant à des milliards de dollars. Dans cet exposé, nous étudions la proportion pondérale optimum de chaux dans la terre en tant que technique servant à réduire le gonflement d´un sol expansif. Nous é tudions é galement une nouvelle technique destinée à améliorer encore davantage l´efficacité de la technique à colonnes de chaux pour réduire le gonflement du sol, nommément des colonnes de chaux renforceès. Cette nouvelle technique consiste à renforcer les colonnes de chaux en utilisant des barres de renfort attachées aux fondations de la structure. L´étude expérimentale passe par des essais en laboratoire sur des lits de sol expansif traité avec des colonnes de chaux supportant des fondations modélisées. Les résultats montrent que la teneur optimum en chaux est de 6% (en poids) de sol à l´intérieur de la colonne. Nous avons trouvé que la technique des colonnes de chaux réduit de 33% le gonflement du sol expansif. Par ailleurs, les colonnes de chaux renforcées réduisent de 69% le gonflement d´une couche de sol identique. Les résultats ont montré é galement que le gonflement d´un sol expansif diminue en proportion avec l´augmentation du taux Lcol/Dsol (longueur des colonnes de chaux par rapport à la profondeur du sol expansif).
Partnership working: case study of a successful partnering relationship on a major UK DBFO road project
Authors: Hodgson G. J. , Rankin R. K. 
Published: November 2009

Much has been said and written about partnering but there are many who are unsure about what it is, what it can do, and where the benefits lie. Partnering has been defined by the Reading Construction Forum as a managerial approach used by two or more organisations to achieve specific business objectives by maximising the effectiveness of each participant's resources. The approach is based on mutual objectives, an agreed method of problem resolution and an active search for continuous measurable improvement. The M6 design, build, finance and operate (M6 DBFO) road project was the first private sector funded road project in Scotland. It upgraded the final Scottish link from central Scotland to the South, previously the A74, to form part of the transEuropean road network. The concession was won by Autolink (M6) plc whose shareholders are Amey, Sir Robert McAlpine, Taylor Woodrow, Barr and Innisfree, a venture capital funder specializing in private finance initiative projects. These four major civil engineering contractors in turn also make up the M6 Joint Venture who are the construction and maintenance company. The construction phase of the project was completed in November 1999. This paper will test the Joint Venture's hypothesis that the M6 partnership is a management structure from which all should benefit by working together towards a common goal in a spirit of trust, openness and harmony. The authors undertook a critical analysis of the partnering network and its implementation, including interviewing key players. The key elements of procurement, namely time, quality and cost, were reviewed to observe the effects partnering had on each of these elements.
Calibrating biomonitors to ecological disturbance: a new technique for explaining metal effects in natural waters
Authors: Luoma Samuel N. , Cain Daniel J. , Rainbow Philip S. 
Published: November 2009

Abstract
Bioaccumulated toxic metals in tolerant biomonitors are indicators of metal bioavailability and can be calibrated against metal-specific responses in sensitive species, thus creating a tool for defining dose–response for metals in a field setting. Dose–response curves that define metal toxicity in natural waters are rare. Demonstrating cause and effect under field conditions and integrated chemical measures of metal bioavailability from food and water is problematic. The total bioaccumulated metal concentration in any organism that is a net accumulator of the metal is informative about metal bioavailability summed across exposure routes. However, there is typically no one universal metal concentration that is indicative of toxicity, especially across species, largely because of interspecies differences in detoxification. Stressed organisms are also only present across a narrow range in the dose–response curve, limiting the use of singles species as both biomonitors and bioindicator of stress. Herein we show, in 3 field settings, that bioaccumulated Cu concentrations in a metal-tolerant, riverine biomonitor (species of the caddisfly genus Hydropsyche spp.) can be calibrated against metal-specific ecological responses across very wide ranges of contamination. Using the calibrated dose–response, we show that reduced abundance of species and individuals from particularly sensitive mayfly families (heptageniid mayflies) is more than 2-fold more sensitive to bioavailable Cu than other traditional measures of stress like EPT or total number of benthic macroinvertebrate species. We propose that this field dose-response curve be tested more widely for general application, and that calibrations against other stress responses be developed for biomonitors from lakes, estuaries, and coastal marine ecosystems. Integr Environ Assess Manag 2010;6:199–209. © 2009 SETAC
Full-Field Streamline Tracing in Complex Faulted Systems with Nonneighbor Connections
Authors: Jimenez Eduardo A. , Datta-Gupta Akhil , King Michael J. 
Published: November 2009

SummaryFull-field flow simulators use a variety of cell geometries, rang-ing from simple rectangles to complex corner-point systems. One of the benefits of corner-point cells is the ease with which we may represent faulted reservoirs. Each face of a cell may be juxtaposed to two or more cells, depending on the fault throw and the lateral displacements of adjacent cells. Conventional finite-dif-ference approaches routinely include the flux between these cells as "nonneighbor" connections. Other examples of nonneighbor or nonstandard connections occur at the boundary of local grid refinement (LGR) or local grid coarsening (LGC) regions where two computational grids come into juxtaposition. In each of these instances, the velocity across the nonstandard faces of a cell will be unevenly distributed according to the nonneighbor fluxes. In contrast, the standard streamline velocity interpolation model (Pol-lock's scheme) used within a cell assumes that the flux is evenly distributed on each cell face, inconsistent with the nonneighbor connection fluxes. Streamlines traced with such an approach do not have sufficient degrees of freedom to be consistent with the finite-difference fluxes and, consequently, will not follow a physical flow path.We propose a strategy that provides a consistent representation for streamlines and velocities near faults and nonneighbor connec-tions. Our approach is based on a simple local (boundary layer) refinement construction that can be used to honor the fluxes at each face, without affecting the representation of flow within the cell or on any other cell face. The local refinement construction is the simplest extension to 3D for faulted reservoir cells that provides consistency with the finite difference flux calculation. Several examples will be presented for a single pair of cells juxtaposed across a fault and at LGR boundaries to illustrate the difficulties in conventional tracing algorithms and the benefits of our approach. The practical utility of our algorithm is demonstrated in a structurally complex and heavily faulted full-field model. The reservoir geometry includes multiple cells with complex fault juxtaposition and several nonneighbor con-figurations in different faces. This treatment is contrasted with the usual approach, and the implications for reservoir scale fluid flow tracing by streamlines is examined.
Simple Analytical Model for Predicting Productivity of Multifractured Horizontal Wells
Authors: Guo Boyun , Yu Xiance , Khoshgahdam Mohammad 
Published: November 2009

Summary
Horizontal wells drilled in the direction of the minimum horizontal stress allow multiple transverse fractures to be hydraulically created for enhancing well productivity in low-permeability oil and gas reservoirs. Dominating factors affecting the productivity of the multifractured horizontal wells vary with reservoir and fracture properties, and with well trajectories. A simple and accurate mathematical model for evaluating and optimizing productivity of this type of well is not available and is highly desirable to reservoir engineers. This paper fills the gap.
After a case study with existing analytical models that were derived for multifractured wells, the authors found that these models cannot describe the performance of oil wells with acceptable accuracy. We then formulated a simple analytical model that describes the productivity of multifractured horizontal wells better. The new model couples the radial flow in the nonfractured region of reservoir, the linear flow toward the fractures in the fractured region, the linear flow in the fracture, and the radial flow in the fracture toward the horizontal wellbore. It can model pseudosteady-state flow of reservoir fluids in reservoir sections of any shape, with the fractured region being located at any area in the reservoir. The difference between the production rate given by the new model and the actual production rates was found to be less than 5% in the two cases studied. This paper provides reservoir engineers a simple and accurate tool for predicting, evaluating, and optimizing the performance of multifractured horizontal oil and gas wells.
Study of the PVT Properties of Gas—Synthetic-Drilling-Fluid Mixtures Applied to Well Control
Authors: Monteiro E. N. , Ribeiro P. R. , Lomba R. F. T. 
Published: November 2009

Summary
The study of the interaction between the formation gas and the drilling fluid during offshore operations as well as in high-pres- sure/high-temperature environments is essential to drill the pay zone of the well safely and economically. The environmental regulatory issues and the peculiar technical aspects involved in deep and ultradeep waters require low-toxicity synthetic drilling fluids. The main objective of this study was to understand the pressure/ volume/temperature (PVT) behavior of those fluids by the experimental determination and modeling of properties such as solubility, specific gravity, and formation volume factor of the fluid. Those properties have a direct impact on kick detection and circulation out of the well and should be addressed in well-control planning and execution. The experimental work was conducted in a PVT laboratory, using mixtures of methane and n-paraffin-based emulsions as unweighted drilling fluids, tested at temperatures of 158, 194, and 302°F. The pressure, temperature, and fluid-composition effects on those gas/liquid mixture properties were analyzed, and the experimental data for solubility and formation volume factor were compared to predictions considering the additivity hypothesis and mathematical fittings based on the experimental data. A model for the methane/n-paraffin system based on literature data and the Peng-Robinson equation of state has also been fitted to the data to discuss the application of the additivity hypothesis for the emulsions. Pit gain evaluation based on the correlated experimental data for the synthetic drilling fluid has been performed and compared to the values expected for water-based muds (WBMs).
New Single-Well Standalone Gas Lift Process Facilitates Barnett Shale Fracture-Treatment Flowback
Authors: Elmer William G. , Elmer Stuart J. , Elmer Thomas E. 
Published: November 2009

Summary
When performing multiple fracture treatments in horizontal Barnett shale wells, many operators choose to use 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 because it allows for high liquid flow rates 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 is available. Operators resort to costly nitrogen-membrane units to provide lift gas but are left with questions about the net gas 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.
Diabetes as a Determinant of Mortality in Cystic Fibrosis
Authors: Chamnan Parinya , Shine Brian S.F. , Haworth Charles S. , Bilton Diana , Adler Amanda I. 
Published: November 2009

OBJECTIVE
Diabetes is increasingly common in cystic fibrosis, but little information describing its influence on mortality exists. Using national U.K. data, in this study we document diabetes-specific mortality rates, estimate the impact of diabetes on survival, and estimate population-attributable fractions.

RESEARCH DESIGN AND METHODS
This retrospective cohort study identified 8,029 individuals aged 0–65 years from the U.K. Cystic Fibrosis Registry (1996–2005). A total of 5,892 patients were included in analyses of mortality rates, and 4,234 were included in analyses of risk factors. We calculated age-adjusted mortality rates using Poisson regression, standardized mortality ratios using the population of England and Wales, and relative risks using proportional hazards modeling.

RESULTS
During 17,672 person-years of follow-up, 393 subjects died. The age-adjusted mortality rate was 1.8 per 100 person-years (95% CI 1.6–2.0). The age-adjusted mortality rates per 100 person-years were 2.0 (1.8–2.4) in female subjects and 1.6 (1.4–1.9) in male subjects, and 4.2 (3.4–5.1) in individuals with diabetes vs. 1.5 (1.3–1.7) in those without diabetes. Independent risk factors for death included diabetes (hazard ratio 1.31 [95% CI 1.03–1.67], female sex (1.71 [1.36–2.14]) plus poorer pulmonary function, lower BMI, Burkholderia cepacia infection, absence of Staphylococcus aureus infection, allergic bronchopulmonary aspergillosis, liver disease, prior organ transplantation, and corticosteroid use.

CONCLUSIONS
Individuals with cystic fibrosis die earlier if they have diabetes, which, if delayed or better treated, might reasonably extend survival; this hypothesis merits testing.
Increased Carotid Intima-Media Thickness as a Predictor of the Presence and Extent of Abnormal Myocardial Perfusion in Type 2 Diabetes
Authors: Djaberi Roxana , Schuijf Joanne D. , Jukema J. Wouter , Rabelink Ton J. , Stokkel Marcel P. , Smit Jan W. , de Koning Eelco J. , Bax Jeroen J. 
Published: November 2009

OBJECTIVE
Identification of asymptomatic patients with type 2 diabetes at increased risk for coronary artery disease (CAD) remains a challenge. We evaluated the potential of carotid intima-media thickness (CIMT) for prediction of abnormal myocardial perfusion in this population.

RESEARCH DESIGN AND METHODS
CIMT and SPECT myocardial perfusion imaging were assessed in 98 asymptomatic patients with type 2 diabetes. An increased CIMT was defined as ≥75th percentile of reference values.

RESULTS
Increased CIMT was an independent predictor of the extent of abnormal perfusion (P &lt; 0.001). In patients with increased CIMT as compared with patients with normal CIMT, abnormal perfusion (75 vs. 9%) and severely abnormal perfusion (28 vs. 3%) were observed more frequently.

CONCLUSIONS
Increased CIMT was significantly related to the presence and extent of abnormal myocardial perfusion. Assessment of CIMT may be useful to identify asymptomatic patients with type 2 diabetes at higher risk for CAD.
Inflammation Markers and Metabolic Characteristics of Subjects With 1-h Plasma Glucose Levels
Authors: Bardini Gianluca , Dicembrini Ilaria , Cresci Barbara , Rotella Carlo Maria 
Published: November 2009

OBJECTIVE
To assess the association of 1-h plasma glucose (1hPG) and inflammation with normal glucose tolerance (NGT) and pre-diabetes.

RESEARCH DESIGN AND METHODS
A cohort of 1,062 subjects was enrolled. After oral glucose load (oral glucose tolerance test), we compared subjects with NGT and pre-diabetes above and below the 1hPG cut point (155 mg/dl). Fibrinogen and leukocytes count (white blood cells [WBCs]) for subclinical inflammation, lipid ratios, insulin sensitivity (Matsuda index) were determined.

RESULTS
Patients with NGT and pre-diabetes (1hPG &gt;155 mg/dl) showed a significant increase of inflammatory markers and lipid ratios (for all, P &lt; 0.05). In age-, sex-, and BMI-adjusted analysis, 1hPG was associated with a significantly higher WBC count and fibrinogen (P &lt; 0.05). Patients with elevated 1hPG showed a highly significant lower insulin sensitivity than subjects &lt;1hPG (P &lt; 0.01).

CONCLUSIONS
Elevated 1hPG in subjects with NGT and pre-diabetes is associated with subclinical inflammation, high lipid ratios, and insulin resistance. Therefore, 1hPG &gt;155 mg/dl could be considered a new “marker” for cardiovascular risk.