bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modellierung des dynamischen Verhaltens der Wärmeübertragung in einem Rauchrohr-Wärmeübertrager Dynamic Modelling of the Heat Transfer in a Gas Tube Heat Exchanger
Authors: Bauer Robert , Gölles Markus , Brunner Thomas , Dourdoumas Nicolaos , Obernberger Ingwald 
Published: October 2008

Zusammenfassung
Um Wärmeübertrager geeignet betreiben zu können, ist es hilfreich ihre dynamischen Eigenschaften zu kennen. Hierzu wird ein einfaches hinreichend genaues nichtlineares Modell zur Beschreibung des dynamischen Verhaltens an Hand eines sogenannten Rauchrohr-Wärmeübertragers hergeleitet. Dieses kann auf Grund des allgemeinen Ansatzes mit geringfügigen Modifikationen für andere Bautypen einfach adaptiert werden. Das vorgestellte Modell kann zur Abschätzung nicht gemessener Größen bzw. des Verschmutzungsgrades sowie zum Entwurf modellbasierter Regelungsstrategien verwendet werden.
Volumetric and Viscometric Behaviour of some Amino Acids and their Group Contributions in Aqueous Tetramethylammonium Bromide at Different Temperatures
Authors: Ali A. , Shahjahan Shahjahan 
Published: October 2008

Abstract
Densities, ρ and viscosities, η for L-serine, L-threonine, L-glutamine, L-lysine, L-arginine and L-histidine (0.05–0.25 m) in 0.20 m aqueous tetramethylammonium bromide were determined at 298.15, 303.15, 308.15, and 313.15 K. The density data was used to compute apparent molar volume, φ

v
. The partial molar volume, φ

v

0, at infinite dilution and experimental slope, S

v

*
were obtained from Masson´s equation and interpreted in terms of solute-solvent and solute-solute interactions, respectively. The φ

v

0 values are found to vary with temperature as a power series of temperature. The structure-making/-breaking ability of solute were discussed using Hepler´s criterion. The partial molar volumes of transfer, φ

v

0
(tr) of amino acid from aqueous to aqueous tetramethylammonium bromide solution were interpretedin the light of cosphere overlap model. The viscosity data was utilized to determine A- and B-coefficients of viscosity, free energy of activation of viscous flow, Δμ
1
0
* and Δμ
2
0
*, per mole of solvent and solute, respectively, and ΔH

*
and ΔS

*
were also evaluated. The linear variation of φ

v

0 and B-coefficient with the number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of (NH3
+, COO–) and CH2 groups to φ

v

0 and B-coefficient, respectively.
Reactions in Fluorinated Acetic Acid Esters Triggered by Slow Electrons: Bond Cleavages, Hydrogen Transfer Reactions and Loss of Halocarbons
Authors: Martin Isabel , Langer Judith , Illenberger Eugen 
Published: October 2008

Abstract
Low energy electron induced reactions in the four fluorinated acetic acid esters CF3COOCH3, CF3COOC2H5, CF3COOCH2CF3 and CH3COOCH2CF3 are studied by means of a crossed electron-molecular beam experiment and mass spectrometric detection of the anions. All target molecules exhibit a prominent resonance located near 1 eV which is subjected to a variety of unimolecular reactions. The observation of the carboxylate anion CF3COO–/CH3COO– indicates rupture of the O−R ester bond, which in turn demonstrates that the prominent cleavage of the O−H bond recently observed in trifluoroacetic acid and acetic acid is not blocked when O−H is replaced by O−R (R=−CH3, −C2H5, −CH2CF3). In CF3COOCH3 and CF3COOC2H5 an ion of the form CF2COO– is generated which is identified to arise from a complex reaction involving multiple bond cleavages and substantial rearrangement in the transitory negative ion ultimately generating CH3F and C2H5F, respectively, as neutral counterpart. A fragment ion of the type (M-H)– (M: target molecule), i.e. loss of a neutral hydrogen atom, is only observed in CH3COOCH2CF3 which directly demonstrates that dehydrogenation selectively occurs at the CH3 site.
Coprinus cinereus rad50Mutants Reveal an Essential Structural Role for Rad50 in Axial Element and Synaptonemal Complex Formation, Homolog Pairing and Meiotic Recombination
Authors: Acharya Sonia N , Many Alexander M , Schroeder Andrew P , Kennedy Felicia M , Savytskyy Oleksandr P , Grubb Jennifer T , Vincent Jack A , Friedle Elizabeth A , Celerin Martina , Maillet Daniel S , Palmerini Heather J , Greischar Megan A , Moncalian Gabriel , Williams R Scott , Tainer John A , Zolan Miriam E 
Published: October 2008

AbstractThe Mre11/Rad50/Nbs1 (MRN) complex is required for eukaryotic DNA double-strand break (DSB) repair and meiotic recombination. We cloned the Coprinus cinereus rad50 gene and showed that it corresponds to the complementation group previously named rad12, identified mutations in 15 rad50 alleles, and mapped two of the mutations onto molecular models of Rad50 structure. We found that C. cinereus rad50 and mre11 mutants arrest in meiosis and that this arrest is Spo11 dependent. In addition, some rad50 alleles form inducible, Spo11-dependent Rad51 foci and therefore must be forming meiotic DSBs. Thus, we think it likely that arrest in both mre11-1 and the collection of rad50 mutants is the result of unrepaired or improperly processed DSBs in the genome and that Rad50 and Mre11 are dispensable in C. cinereus for DSB formation, but required for appropriate DSB processing. We found that the ability of rad50 mutant strains to form Rad51 foci correlates with their ability to promote synaptonemal complex formation and with levels of stable meiotic pairing and that partial pairing, recombination initiation, and synapsis occur in the absence of wild-type Rad50 catalytic domains. Examination of single- and double-mutant strains showed that a spo11 mutation that prevents DSB formation enhances axial element (AE) formation for rad50-4, an allele predicted to encode a protein with intact hook region and hook-proximal coiled coils, but not for rad50-1, an allele predicted to encode a severely truncated protein, or for rad50-5, which encodes a protein whose hook-proximal coiled-coil region is disrupted. Therefore, Rad50 has an essential structural role in the formation of AEs, separate from the DSB-processing activity of the MRN complex.
The Proline-Dependent Transcription Factor Put3 Regulates the Expression of the Riboflavin Transporter MCH5 in Saccharomyces cerevisiae
Authors: Spitzner Andrea , Perzlmaier Angelika F , Geillinger Kerstin E , Reihl Petra , Stolz Jürgen 
Published: October 2008

Abstract
Like most microorganisms, the yeast Saccharomyces cerevisiae is prototrophic for riboflavin (vitamin B2). Riboflavin auxotrophic mutants with deletions in any of the RIB genes frequently segregate colonies with improved growth. We demonstrate by reporter assays and Western blots that these suppressor mutants overexpress the plasma-membrane riboflavin transporter MCH5. Frequently, this overexpression is mediated by the transcription factor Put3, which also regulates the proline catabolic genes PUT1 and PUT2. The increased expression of MCH5 may increase the concentrations of FAD, which is the coenzyme required for the activity of proline oxidase, encoded by PUT1. Thus, Put3 regulates proline oxidase activity by synchronizing the biosynthesis of the apoenzyme and the coenzyme FAD. Put3 is known to bind to the promoters of PUT1 and PUT2 constitutively, and we demonstrate by gel-shift assays that it also binds to the promoter of MCH5. Put3-mediated transcriptional activation requires proline as an inducer. We find that the increased activity of Put3 in one of the suppressor mutants is caused by increased intracellular levels of proline. Alternative PUT3-dependent and -independent mechanisms might operate in other suppressed strains.
Two Adjacent Nucleotide-Binding Site–Leucine-Rich Repeat Class Genes Are Required to Confer Pikm-Specific Rice Blast Resistance
Authors: Ashikawa Ikuo , Hayashi Nagao , Yamane Hiroko , Kanamori Hiroyuki , Wu Jianzhong , Matsumoto Takashi , Ono Kazuko , Yano Masahiro 
Published: October 2008

Abstract
The rice blast resistance gene Pikm was cloned by a map-based cloning strategy. High-resolution genetic mapping and sequencing of the gene region in the Pikm-containing cultivar Tsuyuake narrowed down the candidate region to a 131-kb genomic interval. Sequence analysis predicted two adjacently arranged resistance-like genes, Pikm1-TS and Pikm2-TS, within this candidate region. These genes encoded proteins with a nucleotide-binding site (NBS) and leucine-rich repeats (LRRs) and were considered the most probable candidates for Pikm. However, genetic complementation analysis of transgenic lines individually carrying these two genes negated the possibility that either Pikm1-TS or Pikm2-TS alone was Pikm. Instead, it was revealed that transgenic lines carrying both of these genes expressed blast resistance. The results of the complementation analysis and an evaluation of the resistance specificity of the transgenic lines to blast isolates demonstrated that Pikm-specific resistance is conferred by cooperation of Pikm1-TS and Pikm2-TS. Although these two genes are not homologous with each other, they both contain all the conserved motifs necessary for an NBS–LRR class gene to function independently as a resistance gene.
New Zealand Gas Development Sets New Performance and Environmental Milestones Onshore and Offshore – The Role of Drilling Fluid Selection and Performance in the Pohokura Development
Authors: Knox David , Parr Iain , Tan Ivan , de Lange Frank , Davies Jonathan , McVey Gary , Pritchard Don 
Published: October 2008

Abstract
The Pohokura Gas Field lies off the West Coast of New Zealand in the Taranaki Basin. To develop this field, a total of nine wells were drilled, from both onshore and offshore locations. The extended-reach wells drilled from land set new records for New Zealand, drilling to a measured depth of 7,409 m (24,309 ft) on POW 03, the longest well. The five wells drilled from the offshore drilling unit featured tortuous well paths through the reactive and dispersive shales of the Taranaki Basin. The Pohokura reservoir sands are low-porosity "tight" sandstones, notoriously susceptible to fluid-related production impairment. In addition to these challenges, the onshore and offshore environmental regulations applied both by the local regulator and self-imposed by the operator are among the most strict in Asia.
The fluids-specific challenges associated with this project included the design of a synthetic-based fluid and cuttings handling system that could maintain the fluid-on-cuttings discharge at the lowest practicable level, design of a highly inhibitive and lubricious water-based drilling fluid for the offshore drilling campaign, plus the development and testing of non-damaging drilling fluids for the reservoir sections of all wells.
To achieve these goals, extensive laboratory testing and comprehensive reviews of field experience from other operations were undertaken. Key Performance Indicators were agreed between the operator and fluids provider. These benchmarks were reviewed on a well-by-well basis and used to facilitate ongoing continuous performance improvement.
Sand Management: What Are We Sure Of?
Authors: Slayter A. G. , Byrne M. , McPhee C. A. , McCurdy P. 
Published: October 2008

Abstract
Sand management is an issue pertinent to all those disciplines responsible for maturing a project. It requires leadership from the asset owner, expertise from the specialists and top quality equipment from the vendors. Excellence must span all the stages of field development for, like many aspects of well construction, "9 out of 10" is usually not good enough. For this reason guidance is proposed for management and design of sand related projects.
While sanding prediction is the first step in the process, it is only briefly mentioned in this paper, where focus is more on selected design activities for an openhole production well with sand control, namely: Rock mineralogyParticle size distribution testing (sieve and laser) and the definition / issues relating to finesSelection of sand control system with review of the screen to openhole annulusSand retention testsScreen mesh size assessmentScreen failure mechanisms •Erosion•Collapse and/or bucklingScreen ratings, increasing screen strength where possibleReview of statistics
Although many of the above are relevant to other well designs, no specific reference is made to frac and packs, selective or oriented perforation, sand consolidation, execution or operation of sand control, or surface sand management.
The sand management team needs to define the tasks and activities to achieve established and shared objectives, those objectives being to achieve the required well productivity, longevity and functionality.
Although these objectives are few, they can only be achieved through careful execution of the various tasks and associated activities. Many tasks are entwined between two or three objectives and need to be done in a particular order. This paper proposes a methodical workflow framework to achieve this.
In many cases the answers to design questions are dispersed amoungst an unmanageable number of papers, manuals, guidelines, training and conference proceedings and this paper goes some way to draw the threads together for some of the common design issues. In some areas, work is still to be done by our industry to clarify equipment specification, standardising definitions, test methods, and modeling techniques.
Massive Annular Fracturing Practices in BJC Gas Field, Sichuan, China
Authors: Zhenhui Xing , Pfaff Andrew , Weller Thomas , Weller Thomas , Wendt David 
Published: October 2008

Abstract
Massive hydraulic fracturing has been successfully applied in tight gas reservoir development. Economic completion of tight gas sands with large hydraulic fracturing treatments requires cost effective and time saving operations. Traditional large fracturing jobs usually pump down 5.5" or 4.5" casing to meet the requirement of high pumping rate (30~55bpm). Post-frac snubbing operations are often needed to run tubing and clean out wellbores. Snubbing operations can be costly in terms of investment and time. Annular fracs have been applied in the industry as an alternative completion strategy. However, previously documented annular jobs are small size and range from 40k to 200k lbs of proppant pumped at relatively low injection rates of 15-25 BPM (3-4m3/min).
This paper describes the practices of massive annular fracturing treatments down 5-1/2" by 2-3/8" annulus used at the Bajiaochang Gas field, Sichuan Basin, China, to replace fracturing down casing and subsequent snubbing operations. Three treatments have been performed since October 2005. The first job had to be terminated with 70% of the designed proppant (394k lbs) pumped because of the failure of the blast joint. Lessons learned were outlined and modifications were made to the blast joint and wellhead. Subsequent treatments were performed without mechanical failures with 350k and 282k lbs of proppant pumped at 30 to 35 bpm injection rates. The completion cycle time was reduced about 20% with substantial savings of up to $260k in well completion costs. Improved monitoring of BHP from static tubing for 3D fracturing modeling and effective treatment evaluation were also a benefit. This data has aided fracture design in highly complex fracture stimulation applications. Additional advantages also include: easily circulating out proppant if screen outs occur and more efficient flowing back for lower rate wells.
Optimum Formulation of Alkaline-Surfactant-Polymer Systems for Enhanced Oil Recovery
Authors: Mandal Ajay , Ojha Keka 
Published: October 2008

Abstract
The primary objective of this paper is to obtain an optimized condition where different concentrations of alkali, surfactant and polymer can produce desirable rheological properties and interfacial tension for its use in enhanced oil recovery. In the present study, the aqueous solutions of polyacrylamide were used to improve the mobility ratio by increasing the viscosity of the solution. A series of experiments were conducted to examine the effects of various salts, alkali and surfactants on the viscosity polymer solutions. The experiments were also performed to measure the reduction of surface tension of aqueous solutions of surfactants and alkali at different concentration, in presence and absence of polymer. The experimental data on viscosity and surface tension were analyzed and an optimum formulation of the alkali, surfactant and polymer were designed, which provide optimum properties with respect to both mobility and interfacial tension between oil and water.
A Fibre Optic Multi-Component Seismic Acquisition System for Permanent Reservoir Monitoring
Authors: Maas Steve , Bunn Brett , Hendrick Natasha 
Published: October 2008

Abstract
A fibre optic multi-component seismic acquisition system for permanent installation on the sea floor has been developed and tested. Permanent seafloor seismic installations are an alternative to other marine seismic acquisition methods for time-lapse (or 4D) seismic reservoir monitoring. 4D seismic can assist reservoir engineers to monitor fluid injection and drainage of the reservoir, and help determine detailed reservoir fluid-flow models. The new fibre optic system uses a Dense Wavelength Division Multiplexing telemetry scheme to optically power the seismic sensors. This methodology allows for channel counts in excess of 2000 per cable. Furthermore, the fibre optic system has a very broad processing bandwidth that yields exceptional dynamic range (&gt; 140dB), which together with low channel crosstalk and distortion, will produce high quality seismic images. The multi-component sensors at each receiver station are optical transducers made using Michelson interferometers. Avoiding in-sea electronics creates a safe and robust system, and utilisation of standard telecommunication components ensures an economically viable reservoir monitoring tool. Field trials conducted in hydrocarbon provinces demonstrate the reliability and excellent response of the fibre optic system to the seismic source. The seismic data acquired by the new fibre optic acquisition system show good correlation with data acquired in parallel using a conventional electrical seafloor acquisition system.
Applications of Multiphase Technologies Optimize Upstream Operations in Saudi Aramco
Authors: Hamoud A. A. , Al-Ghamdi S. M. 
Published: October 2008

Abstract
New oil fields are hard to develop and mature oil fields are becoming more challenging and costly to operate. Advances in multiphase technologies have made significant impact on the way oil and gas companies managing and optimizing their upstream oil business. Multiphase technologies, including multiphase pumping, multiphase flow metering and compact separation systems, have been recognized to provide the critical need to alleviate production decline, optimize production operation, and reduce capital and operating costs.
In this regard, Saudi Aramco has undertaken a number of new production related initiatives, developments and projects involving multiphase technologies that are deemed to provide advantages in achieving corporate goals and objectives. The company has invested and implemented significant new multiphase technologies with the goal of maximizing production and minimizing capital investment and operating costs.
Multiphase Pumping (MPP) technology provides a cost effective option to develop remote and marginal oil field discoveries. MPP showed excellent performance during field test projects and resulted in significant incremental oil production. Applications of Multiphase Flow Metering (MPFM) technology has resulted in significant capital and operating cost savings. Continuous and real-time data has enhanced production and reservoir management, which led to improved total recovery. Compact Separation technology is another area Saudi Aramco is committed to pursue its field implementation. The technology has the potential to de-bottleneck existing facilities capacity limitation, and reduce facility cost for new oil and gas field developments.
This paper will provide an overview of the multiphase technologies Saudi Aramco is considering for field applications. It will also discuss Saudi Aramco's experience and future potential applications. The applications discussed have either been implemented or are expected to be implemented in the near future.
Key Technologies of Polymer Flooding in Offshore Oilfield of Bohai Bay
Authors: Zhou W. , Zhang J. , Feng G. , Jiang W. , Sun F. , Zhou S. , Liu Y. 
Published: October 2008

Abstract
Bohai Bay is one of the most important offshore oil production areas in China, and 74% of oil is heavy oil. For conventional heavy oil reservoirs, water flooding is applied normally with an inverted 9-spot flood pattern. The recovery is about 18~20% because of the heterogeneous and unconsolidated reservoirs. The current strategy for application of polymer flooding to enhance heavy oil recovery is based on the fully understanding of mechanisms and core technologies of polymer flooding in the laboratory research and field practice.
Single well pilot test and 5-spot flood pattern pilot test have been conducted in Bohai oilfield. The significant increase of oil production and reduction of water cut were observed. The limited life span of offshore platforms challenges operators to more effectively develop oil, thus it is necessary to identify the appropriate enhanced oil recovery (EOR) technology for use in a reservoir. Therefore, polymer flooding in early stage of oilfield development has been designed and conducted in Bohai oilfield. Five key technologies of polymer flooding concluded from the field practices were critical to the success of an EOR project and discussed in this paper. (1) Characteristics of polymer: polymer should tolerate high salinity and hardness of make-up brine. (2) Polymer injection technology: the technology should satisfy the requirement of offshore platform. (3) Modification of Polymer displacement under the big well spacing and multi-layer reservoir conditions. (4) Evaluation technology of polymer flooding in the early stage of oilfield development. (5) Production treatment technology of polymer flooding. This paper will focus on the impact of the five key technologies on development of offshore oilfields through introducing polymer flooding in Bohai Bay.