bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of SO2-ethanol-water pulping of spruce 10th EWLP, Stockholm, Sweden, August 25–28, 2008
Authors: Iakovlev Mikhail , Pääkkönen Timo , van Heiningen Adriaan 
Published: July 2009

Abstract
SO2-ethanol-water (SEW) pulping is a promising fractionation process for lignocellulosics to produce pulp and value-added chemicals as a contribution to the concept of forest biorefinery. The presence of SO2 leads to dissolution of hemicelluloses in high yield mostly as monomeric sugars, while lignin becomes soluble through sulfonation. After lignin removal, the dissolved sugars may be used as feedstock for fermentation to ethanol or butanol. SEW pulping may be considered a hybrid between solvent pulping (organosolv pulping by solvolysis) and acid sulfite pulping. Absence of an inorganic base leads to simplification of the recovery cycle. Furthermore, alcohol increases the impregnation rate of dissolved SO2 into wood, so that a separate impregnation phase is not necessary. Also, the presence of SO2 allows cooking of softwoods, while ethanol pulping is limited to hardwoods. Thus, SEW pulping may be applied to a wide variety of lignocellulosics at lower temperatures and similar cooking times than those used in kraft pulping. In the present study, SEW pulping experiments were performed on spruce chips at cooking temperatures of 135–165°C with a 12% SO2 solution at a liquor-to-wood ratio of 6:1 l kg-1. The effect of cooking temperature and time on kappa number, yield, and intrinsic viscosity of the pulp was determined. Based on these results, the kinetics of delignification, hemicelluloses removal, and cellulose hydrolytic destruction were established.
MEA/water/AQ-pulping of wheat straw
Authors: Hedjazi Sahab , Kordsachia Othar , Patt Rudolf , Kreipl Andreas 
Published: July 2009

Abstract
Annual plant pulping is faced with serious challenges. Traditional pulping processes with bleaching in chlorine based sequences and without appropriate chemical recovery system cannot be tolerated anymore. Alternative pulping processes with non-conventional chemicals, such as organic solvents, e.g., monoethanolamine (MEA), might be suited for an environmentally sound process with a closed mill system. Thus, pulping of wheat straw with MEA as the main delignifying agent was investigated in comparison to soda and soda/AQ pulps as references. The main focus was placed on reduction of the cooking temperature in order to avoid heat-induced MEA degradation. The temperature was reduced stepwise from 165°C to 130°C. At 150°C, a sufficient delignification was achieved. MEA was partly substituted by water and the resulting decrease of the delignification rate could be compensated by addition of anthraquinone (AQ). After optimization of the process, a pulp with a kappa number of 17 was obtained at a total yield of 56% based on o.d. straw. This pulp was selected for bleaching. Both, O/Q/OP/DQ/P (“ECF light”) and O/Q/OP/ZQ/P (TCFZ) bleaching were applied. NaOH was substituted by MEA as alkali source in the oxygen delignification stage. Up to 50% delignification rate was achieved under these moderate conditions. In the ECF light bleaching sequence, a brightness of 80% ISO was reached at a kappa number level below 3. In TCFZ bleaching, an even somewhat higher brightness was achieved at a kappa number level below 1. A yield of fully bleached screened pulp of around 50% (based on o.d. straw) was obtained. The strength properties of the MEA pulp were improved after bleaching. ECF bleaching resulted in slightly better pulp strengths than the TCFZ alternative. MEA forms in combination with water and AQ a very selective pulping system providing effective delignification and maintaining extremely high yields. MEA/water/AQ pulping should be regarded as a serious, environmentally friendly alternative to soda or soda/AQ pulping to produce high-quality pulp from wheat straw.
Decay resistance of acetylated and hexanoylated hardwood and softwood species exposed to Coniophora puteana
Authors: Hill Callum A.S. , Curling Simon F. , Kwon Jin H. , Marty Virginie 
Published: July 2009

Abstract
The effect of chemical modification with acetic or hexanoic anhydride upon the decay resistance of wood was studied. Both sapwoods and heartwoods of the following trees were investigated: Japanese larch, Larix kaempferi (Lamb.) Carrière; Korean pine, Pinus koraiensis Siebold et Zucc. as softwoods and European beech (only sapwood), Fagus sylvatica L.; oriental white oak, Quercus aliena (Blume) as hardwoods. After chemical modification, the samples were exposed to the brown rot fungus Coniophora puteana (FPRL 11E). The study investigated whether weight percentage gain or degree of hydroxyl substitution were the main factors controlling decay resistance. It was found that decay resistance is associated primarily with cell wall bulking rather than hydroxyl substitution. However, there are differences in behaviour between the acetylated and hexanoylated wood and the possible reasons for these differences are discussed.
Minimizing Machining Distortion in Aluminum Alloys through Successful Application of Uphill Quenching—A Process Overview
Authors: Croucher Tom 
Published: July 2009

Abstract
Recently, emphasis has been placed on achieving maximum dimensional stability in a wide range of critical aluminum components such as large complex aerospace machined parts, space mirrors, optical stages, lens mounts, and computer disks. In these cases, absolute stability is required before putting a part into service. In many cases, successful operation of a complete system hinges on the stability of a single part such as a space mirror in a satellite or a component of a laser guided missile. Proper application of the uphill quenching process has enabled the successful production of parts to provide minimum stresses resulting in the optimum component at the lowest cost. Basic principles for achieving dimensional stability and considerations for proper application of unique tools such as polyalkylene glycol polymer (glycol) quenching and uphill quenching to achieve maximum dimensional stability are discussed. Properly applied, and combined with an understanding of all factors contributing to part instability, these tools can be used as effective elements in a systems approach, which when effectively employed by experienced technicians, will achieve results not obtainable by other means. In addition, examples are provided illustrating successful use of the process to produce low stress parts.
Guidelines for Improving the Standard Fire Resistance Test Specifications
Authors: Kodur V. K. R. , Fike R. 
Published: July 2009

AbstractThe current approach of evaluating fire resistance is mainly through standard fire tests. The specifications for standard fire tests have a number of drawbacks and require only a limited amount of data to be collected during tests, and this is hindering the development of calculation methodologies for evaluating fire resistance. This paper discusses the various drawbacks in the current specifications for undertaking fire resistance tests. The improvements needed to make the standard fire resistance tests more effective and the collected test data more useful are outlined. Strategies for implementing the proposed recommendations (improvements) in test standards are illustrated with examples. Finally, the applicability of the proposed recommendations is illustrated by undertaking fire resistance tests on a midsized column and a midsized beam under improved test specifications. Data collected from these fire resistance tests is used to calibrate finite element based computer models, thus demonstrating the effectiveness of collecting additional test data.
Reservoir Technical Limits: A Framework for Maximizing Recovery From Oil Fields
Authors: Smalley P. Craig , Ross Bill , Brown Chris E. , Moulds Tim P. , Smith Mike J. 
Published: July 2009

Summary
The Reservoir Technical Limits (RTL™) approach described herein has proved highly effective at identifying those activities and technologies required to push oilfield recovery factors toward their maximum potential. It combines classical reservoir engineering approaches, together with knowledge of existing and novel recovery-enhancing technologies, to create a common framework for identifying specific actions to increase recovery factor. RTL is implemented in a structured workshop supported by a software toolkit.
The RTL workshop involves the cross-disciplinary field team (in-depth field knowledge), external technical experts (challenge, cross-fertilization), and trained facilitation. The software toolkit encourages innovation in a structured and reproducible manner and documents the outcomes in a consistent format. The RTL conceptual framework represents a recovery factor as the product of four efficiency factors: (1) pore-scale displacement (microscopic efficiency of the recovery process); (2) drainage (connectedness to a producer); (3) sweep (movement of oil to producers within the drained volume); and (4) cut-offs (losses related to end of field life/access). RTL encourages identification of new "opportunities," specific activities or projects that, if implemented, increase one or more efficiency factor, and thus increase recovery relative to the current field Depletion Plan. New ideas are stimulated by comparing current efficiency values with the effects of successful prescreened activities from analogue fields. The identified opportunities are validated by benchmarking: (a) internally, comparing recovery factors derived from summing the opportunity volumes with recovery factors derived from the expected efficiency factor increments; and (b) externally, comparing with analogue fields.
The result is a prioritized list of validated opportunities and an understanding of how each activity affects the reservoir to increase recovery. The opportunities (and any required new technologies) are valued in terms of the resultant incremental barrels. The RTL approach is a significant innovation, because it provides a systematic framework to: (a) identify new recovery-increasing activities across a portfolio of fields; (b) engender ownership of these activities by the individual field teams; and (c) identify the technology requirements to progress the opportunities. Now, having been implemented in more than 200 fields, this systematic approach has enabled opportunity descriptions/values and technology requirements to be compared consistently across all fields, thereby improving project prioritization and focusing corporate technology development and deployment onto the highest impact areas.
Successful Hybrid Slickwater-Fracture Design Evolution: An East Texas Cotton Valley Taylor Case History
Authors: Handren Patrick , Palisch Terry 
Published: July 2009

Summary
As the development of tight/unconventional and partially depleted gas reservoirs has increased, so has the demand for more-innovative hydraulic-fracture designs. Operators are increasingly placing proppant with slickwater, linear gel, or hybrid fracture designs. While the benefits of these designs typically are attributed to a reduction in gel damage of the proppant pack, many operators mistakenly believe that the resulting fractures are not conductivity-limited.
Because few (if any) models on the market can adequately model the propagation of a slickwater fracture along with the associated proppant transport and deposition, it becomes difficult to optimize these fracture designs. This has led many operators to assume incorrectly that only small-diameter sand or resin-coated sand may be placed in these types of designs, and that these products supply ample flow capacity.
However, one east Texas operator has combined insight into proppant transport with an appropriate understanding of realistic proppant-pack conductivity to develop a novel, hybrid slickwater-fracture design. This design has allowed the placement of larger-diameter, higher-conductivity proppant in fractures that many believed could not be placed in fractures either operationally or economically. Additionally, this operator has developed a unique pumping strategy to place the highest-conductivity proppant in portions of the fracture where it provides the most value.
This paper will present a case history of these new hybrid slickwater-fracture designs in this operator's east Texas Cotton Valley Taylor (CV-T) completions. The design theory and sequential improvements will be documented, including larger-diameter, higher-strength proppants, and a novel placement design. Field results from the first six wells fractured will be presented, showing substantial increases in gas production compared with similar offset completions. Economics will also be shown to illustrate the tremendous value added to completions using this hybrid fracture design.
Gelled Scale Inhibitor Treatment for Improved Placement in Long Horizontal Wells at Norne and Heidrun Fields
Authors: Selle Olav Martin , Springer Martin , Auflem Inge H. , Chen Ping , Matheson Rozenn , Mebratu Amare , Glasbergen Gerard 
Published: July 2009

Summary
The success of a scale inhibitor treatment depends on placement efficiency. The scale inhibitor should be placed so that all water-producing intervals accept a sufficient quantity of the total treatment volume. If significant permeability or pressure variations are present in the interval to be treated, treatment fluid will enter the zones with the higher permeability and lower pressure, leaving little fluid to treat the other zones, which can be the water-producing zones. The challenge is even greater in long, horizontal wells with significant permeability and pressure contrast.
To achieve a more uniform fluid coverage, the original flow distribution across intervals often needs to be altered. The methods used to alter this are called "diversion" methods. The purpose is to divert the flow from one portion of the interval to another. In response to this challenge, a joint study with the objective of improving the placement of treatment fluids was initiated by a major operator in the North Sea and two service companies in 2002.
The joint work resulted in development of a fully viscosified scale inhibitor system. The system comprises a purified xanthan viscosify-ing agent, a standard scale inhibitor for downhole scale squeezing, and a breaker to achieve controlled gel breaking down hole.
The system has been field tested at Norne field in two long horizontal wells and at Heidrun field in one long deviated well, all with significant permeability variations and crossflow. The operations were successful and the scale treatments have protected the wells from scaling. This paper describes the product qualification process, placement simulation, temperature prediction, gel breaking characteristics, case histories, and post-job evaluation.
Finite Element Modeling of Casing in Gas-Hydrate-Bearing Sediments
Authors: Salehabadi Manoochehr , Jin Min , Yang Jinhai , Haghighi Hooman , Ahmed Rehan , Tohidi Bahman 
Published: July 2009

Abstract
Casing integrity in shallow marine sediments could be challenging if natural gas hydrates exist in the sediments. Elevated wellbore temperature during drilling of deeper sections of deep offshore wells can cause in-situ gas hydrates to dissociate, thereby increasing pore pressure and altering the mechanical properties of the sediments. Gas hydrate can also dissociate during setting and/or cementing, causing gas release, which could result in delaying completion of the wellbore because of the flow of gas around the casing (conductor pipe) or affecting the casing integrity or casing stability by creating voids (channels) in the cement sheath leading to nonuniform stress loadings.
In this communication, a numerical model is developed using a finite-element code to simulate the stability of casing in gas-hydrate-bearing sediments by considering the interaction between the formation, the casing, and the cement with coupling the ther-modynamic stability of the hydrates to hydraulic, mechanical, and heat transfer terms. The mechanical and hydraulic terms are fully coupled, and the coupling between mechanical and thermal terms is modeled through staggered technique (one-way coupling).
To model the worst-case scenario, the permeability of gas-hydrate-bearing sediments is assumed very low; as a result, the gas and water generated during gas-hydrate dissociation cannot flow and will increase pore pressure. The mechanical property degradation of formation caused by hydrate dissociation is represented in the model by cohesion softening as a function of dissociated gas hydrate saturation.
The developed numerical model is found to be very useful in understanding the behavior of wellbores drilled in gas-hydrate-bearing sediments, which will help the determination of the resultant stress fields and enable a more accurate determination of the required casing strength.
Thermodynamic Modeling of Naphthenate Formation and Related pH Change Experiments
Authors: Mohammed Murtala A. , Sorbie K. S. , Shepherd A. G. 
Published: July 2009

Summary
The prediction and prevention of both sodium and calcium naphthenate "scales" is an important issue in oil production. A broad description of how these scales form has been available for some time, although most experimental findings are still of a qualitative nature. In this paper, an equilibrium thermodynamic model is presented for predicting naphthenate partitioning and precipitation in an oil/brine immiscible system from some chosen initial conditions (i.e., naphthenate initial concentration in oil, brine pH, [Ca2+], etc.). This model has, with some assumptions, been applied to both model and real naphthenate system.
This model describes two types of naphthenate experiment: 1) full naphthenate precipitation, and 2) simpler "pH change" experiments in which no precipitation occurs. To predict naphthenate precipitation, the theory suggests knowing: 1) the partition coefficient of the naphthenic acid, HA, between the oil and the water phases, Kow; 2) the pKa of the naphthenic acid in water; and 3) the solubility product, KCaA2 (or other similar solubility parameter), of the naphthenate deposit. In the simpler pH change experiments, only the first two of these parameters (i.e., Kow and pKa) are required. Using the naphthenate model without precipitation, the effect of varying parameters on the degree of pH change predicted at equilibrium in the oil/naphthenic acid/brine system was studied. Also, the model was used to examine the sensitivities of the various parameters on the final pH was also applied. The comparison between the model predictions and experiment at a higher brine pH value is overall satisfactory.
Modeling the Impact of Diesel vs. Water Overflush Fluids on Scale-Squeeze-Treatment Lives Using a Two-Phase Near-Wellbore Simulator
Authors: Vazquez O. , Mackay E. , Jordan Myles 
Published: July 2009

Summary
This paper describes the development of a two-phase near-wellbore simulator to predict the impact on squeeze lifetime of the overflush fluid type. In the past, a single aqueous-phase model was used for a diesel overflush treatment. The new model enables a more accurate description of the displacement process and the impact of inhibitor transport through the formation and retention on the rock matrix.
Field data are presented, with various treatments being considered. In each case, the well was treated with the same aqueous scale inhibitor (SI). The initial squeeze treatments used a diesel overflush. However, subsequent treatments used the same inhibitor but used seawater as the overflush fluid. It is clear from the field returns that the use of seawater rather than marine diesel improved chemical placement and extended treatment life. The theory behind this phenomenon is outlined, so allowing for more accurate treatment designs.
The process followed involved first deriving an isotherm using a single-phase squeeze model based on the water overflush treatment. This is the established conventional approach used in many hundreds of cases worldwide. This isotherm was then used to model the same treatment using the new two-phase model, which accounts for saturation changes during the treatment. A good match was achieved using the isotherm, giving confidence that the two models agree for purely aqueous treatments. A diesel overflush treatment was then simulated using the two-phase model and the same isotherm, and again a good match was achieved. However, modeling the diesel overflush treatment in the single-phase model required a different isotherm to achieve the match. This clearly indicates that diesel overflush treatments may be modeled accurately using the two-phase model. Additional sensitivity calculations were performed to investigate the impact of splitting the overflush volume into separate diesel and water stages.
Effects of Hand Cycle Training on Physical Capacity in Individuals With Tetraplegia: A Clinical Trial
Authors: Valent Linda J.M. , Dallmeijer Annet J. , Houdijk Han , Slootman Hans J. , Janssen Thomas W. , Post Marcel W.M. , van der Woude Lucas H. 
Published: July 2009

BackgroundRegular physical activity is important for people with tetraplegia to maintain fitness but may not always be easily integrated into daily life. In many countries, hand cycling has become a serious option for daily mobility in people with tetraplegia. However, little information exists regarding the suitability of this exercise mode for this population.ObjectiveThe purpose of this study was to evaluate the effects of a structured hand cycle training program in individuals with chronic tetraplegia.DesignPretraining and posttraining outcome measurements of physical capacity were compared.SettingStructured hand cycle interval training was conducted at home or in a rehabilitation center in the Netherlands.ParticipantsTwenty-two patients with tetraplegia (American Spinal Injury Association Impairment Scale classification A-D) at least 2 years since injury participated.InterventionThe intervention was an 8- to 12-week hand cycle interval training program.MeasuresPrimary outcomes of physical capacity were: peak power output (POpeak) and peak oxygen uptake (V̇o2peak), as determined in hand cycle peak exercise tests on a motor-driven treadmill. Secondary outcome measures were: peak muscle strength (force-generating capacity) of the upper extremities (as assessed by handheld dynamometry), respiratory function (forced vital capacity and peak expiratory flow) and participant-reported shoulder pain.ResultsSignificant improvements following a mean of 19 (SD=3) sessions of hand cycle training were found in POpeak (from 42.5 W [SD=21.9] to 50.8 W [SD=25.4]), V̇o2peak (from 1.32 L·min−1 [SD=0.40] to 1.43 L·min−1 [SD=0.43]), and mechanical efficiency, as reflected by a decrease in submaximal oxygen uptake. Except for shoulder abduction strength, no significant effects were found on the secondary outcomes.LimitationsCommon health complications, such as urinary tract infections, bowel problems, and pressure sores, led to dropout and nonadherence.ConclusionPatients with tetraplegia were able to improve their physical capacity through regular hand cycle interval training, without participant-reported shoulder-arm pain or discomfort.