bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Evaluation of MOV Adjustable Steam Chokes
Authors: Latif Faisal , Castrup Suzanne , Al Kalbani Ali 
Published: March 2012

Abstract
Controlling and monitoring steam injection into heavy oil reservoirs are important elements of heat management. Static chokes with tapered-bean inserts are the most reliable and cost-effective means of controlling wellhead steam injection rates. However, adjustable steam chokes are often used because Rate changes can be made without interruption of steam supply to the well.An inventory of bean inserts is not required.
Adjustable or multiple orifice valve (MOV) chokes have two disks, each with a pair of holes (orifices). The size of the choke opening is adjusted by rotating one disk causing the two pairs of holes on each disk to overlap by differing amounts. This paper presents the results of field tests conducted to assess the flow control and monitoring capability of MOV steam chokes. Topics include adjustment precision and reproducibility, critical and subcritical flow conditions, and comparison of calculated and measured flow rates.
Water Injector Matrix Acidizing: Evaluation of Tools Deployed on Coiled Tubing Used for Placement
Authors: Trehan Rakesh , Jones Norman , Meraz-Mata Vincent 
Published: March 2012

Abstract
Successful acid treatment depends largely on the method used to place the acid. Water-injection wells are commonly treated using coiled tubing (CT) and a high-pressure nozzle to increase the well's injection rate. This paper focuses on the comparison of two types of high-pressure nozzles, as used in a slotted-liner cleanout in a sandstone formation.
A majority of the diversion techniques available are classified as mechanical, such as straddle packers, opposing cup tools, particulates, and perforation ball sealers. In addition, the industry uses a variety of chemical diverters, such as gelled acids and foamed acid. These options might work fine in perforated and cemented casing, but there are not many effective options available with respect to matrix acidizing of long, uncemented slotted liners in sandstone formations.
CT acid jobs have typically used nozzles, such as the fixed nozzle, rotating-jet nozzle, and the fluid oscillating (FO) nozzle. However, the newest innovation in fluid-oscillating tools is the fluid-oscillating tuned frequency and amplitude (FOTFA) nozzle, which is more efficient than the previous fluid oscillating tuned frequency (FOTF) nozzles.
This paper presents case histories that compare the results of acid jobs using rotating jet nozzles and the latest FOTFA nozzles. Four analogous water-injection wells were chosen for the trial and were acid stimulated using CT. Two wells were acidized using a rotating nozzle and the other two with the FOTFA nozzle. The wells are in the same field and were treated using the same acid design and pumping procedures.
Experiments on Pulse Power Fracturing
Authors: Mao Ronghai , De Pater Hans , Leon Jean Francois , Fram Joe , Storslett Stein , Ewy Russ , Stefani Joe 
Published: March 2012

Abstract
Pressure pulses generated by sparks in water-filled boreholes generate hydraulic fractures in the dynamic regime. Using triaxially stressed model tests, we investigated the potential for multiple fracturing and the expected size of the fractures. In the tests, we determined the power level at which the pulse initiates a fracture and the final fracture geometry after applying many pulses. A dynamic fracture model is used to explain the attenuation of the pulses. Dynamic fracturing is still poorly understood. Lab tests are needed to benchmark simulation codes that predict fracture length and multiple fractures.
In the tests, we varied the number of notches in the wellbore, stress and rock type. Tests on blocks of cement and oil shale show that pulses of a few kJoule can generate pulses up to 50 MPa that induce multiple fractures and create fairly large fractures, depending on rock type. Bi-wing fractures were generated without notching the borehole. With 4-8 notches the fractures initiated from the notches. Attenuation of the pulses was found to depend mainly on turbulent friction in the fractures.
Pulse power has the advantage that it can generate many pulses in the same zone and can be applied quickly to stimulate multiple zones. This may be favorable compared with propellant fracturing. Pulse power fracturing may be used for stimulating very tight reservoirs, for improving breakdown or for initiating fractures at specific locations.
NFFLOW: A Reservoir Simulator Incorporating Explicit Fractures
Authors: Boyle E. J. , Sams W. N. 
Published: March 2012

Abstract
NFFLOW is a research code that quickly and inexpensively simulates flow in moderately fractured reservoirs. It explicitly recognizes fractures separately from rock matrix. In NFFLOW fracture flow is proportional to the pressure gradient along the fracture, and flow in the rock matrix is determined by Darcy&apos;s Law. The two flow mechanisms are coupled through the pressure gradient between a fracture and its adjacent rock matrix. Presented is a promising change to NFFLOW that allows for flow across a rock matrix block.
Design Considerations of Waterflood Conformance Control with Temperature-Triggered Low Viscosity Sub-Micron Polymer
Authors: Izgec O. , Shook G. M. 
Published: March 2012

Abstract
In waterfloods, the existence of highly conductive thief zones causes poor volumetric sweep efficiency, resulting in early breakthrough and excessive production of water. A conventional strategy of redirecting injection by closing off perforations yields short-term benefits because diversion occurs near the wellbore. As an alternative, temperature-triggered sub-micron polymers with low viscosity (popping agents), which gives an opportunity for conformance control deep in the reservoir, have been introduced in recent years. This technology aids conformance control by plugging the high permeability zones and diverting the fluid to the unswept portion of the reservoir.
Understanding the critical parameters that leads to a successful treatment and accurate determination of the slug size are two important criteria for a technically and economically successful treatment. In this study, first we investigate the effect of different parameters on the success of a conformance control treatment. A comprehensive design of experiments (DoE) study resolves the effects (and combined effects) of kv/kh, treatment fluid concentration, thief-to-matrix permeability ratio, mobility ratio and location of the placement in the reservoir. Next, a methodology is developed for accurate determination of the conformance slug size. The method is built on the temporal moment and residence time distribution analysis (RTDA) of interwell tracers. Dynamic flow- and storage-capacity curves are used to identify the optimum slug size.
3D thermal computer simulations show that thief-zone to matrix permeability ratio and placement location of the polymer are the most important parameters that affect the success of a treatment. The most desirable setting is placing the polymer deep in the reservoir, closer to the producer within high kv/kh reservoirs. Furthermore, the computer simulations confirm the power of the new optimum slug size determination technique. This new technique can avoid underestimation of the volume that needs to be treated which is critical for success of a treatment.
Dedicated detector for verification of X-ray energy in the linear accelerators for cargo screening and industrial radiography
Authors: Kaminski Przemyslaw , Wronka Slawomir 
Published: March 2012

Dedicated detector for verification of X-ray energy in the linear accelerators for cargo screening and industrial radiography
The novel type of detector for X-ray energy evaluation has been developed. Thanks to a simultaneous analysis of the attenuation of X-rays by different thicknesses of well known material, the maximum energy of electrons on the conversion target can be deducted. Fast operation allows for pulse-to-pulse measurement, which is a must for modern, interlaced-energy cargo inspection systems. In this article the construction of the detector and software description are presented.
Application of recombination chambers for determination of neutron ambient dose equivalent at the door to the maze of linear accelerator vault
Authors: Jakubowska Edyta , Golnik Natalia , Gryzinski Michał , Tulik Piotr 
Published: March 2012

Application of recombination chambers for determination of neutron ambient dose equivalent at the door to the maze of linear accelerator vault
Recombination chambers and 2202D Studsvik-Alnor reference remmeter were used for determination of ambient dose equivalent, H*(10) and its neutron and gamma components at the door to the maze of 15 MV medical accelerator. The measurements were performed at opened and partly closed door. The results showed that the ambient dose equivalent rate was 76.2 μSv h-1 at the opened door and only 2.7 μSv h-1 at slightly opened door, 2.5 m from the entrance to the maze.
Development of international coordination of research activities in the EU through ERA-NET and ERA-NET Plus: general trends and situtation in the Czech Republic
Authors: Havlíčková Lenka , Vavříková Lucie 
Published: March 2012

Rozvoj mezinárodní koordinace výzkumných aktivit v EU prostřednictvím nástrojů ERA-NET a ERA-NET Plus: obecné trendy a situace v ČR
Projekty typu ERA-NET jsou nástrojem k propojení národních, regionálních a jiných dílčích výzkumných programů, intenzivnější propojení je pak realizováno schématy ERA-NET Plus a na základě čl. 185 Smlouvy o fungování EU. Článek se zabývá aktuální situací při realizaci těchto schémat. Zmiňuje vznik těchto projektů, jejich poslání a vysvětluje jejich rozsah. Formou mezinárodního srovnání analyzuje zapojení jednotlivých států do těchto projektů s důrazem na účast českých institucí. Vzhledem k nižšímu zapojení ČR se dále zabývá možnostmi české účasti. Přináší výsledky dotazníku ohledně zapojení do výzev, které jsou ve schématu ERA-NET vyhlašovány.
Data Analytical Processing in Data Warehouses
Authors: Rostek Katarzyna 
Published: March 2012

Data Analytical Processing in Data Warehouses
The article presents issues connected with processing information from data warehouses (the analytical enterprise databases) and two basic types of analytical data processing in data warehouse. The genesis, main definitions, scope of application and real examples from business implementations will be described for each type of analysis. There will be presented copyrighted method of knowledge discovering in databases, together with practical guidelines for its proper and effective use in the enterprise.
Soil mechanical resistance measurement by an unique multi-cone tips horizontal sensor
Authors: Sharifi A. , Mohsenimanesh A. 
Published: March 2012

Soil mechanical resistance measurement by an unique multi-cone tips horizontal sensorAmulti-tips horizontal sensor was developed and mounted horizontally on a tine face by shafts. The length of shafts was reduced from top to down the tine. The developed system was evaluated in the controlled soil bin laboratory conditions with clay loam soil and uniform soil moisture content. The experiment was designed with soil compaction at three levels of uniform and non-uniform soil compaction in completely randomized block design with four replications. Vertical standard penetrometer was also used to compare with horizontal sensor data at whole working depth of 0 to 400 mm. The results indicated that there is a correlation with R2= 0.86 between soil cone penetrometer values and the horizontal soil mechanical resistance measurement system data. It can be concluded that the idea of reducing the length of the tips from top to down the tine face would give promising results.
“Secondary stem lengthening” in the palm Iriartea deltoidea (Arecaceae) provides an efficient and novel method for height growth in a tree form
Authors: Renninger Heidi J. , Phillips Nathan 
Published: March 2012

• Premise of the study: Although traditionally assumed that all height growth in trees occurs at apical meristems, sequential measurement of internode lengths in the palm Iriartea deltoidea suggested that stems were lengthening long after the differentiation of tissues and far below the apical meristem. This observation is difficult to reconcile with the fact that neither the water‐conducting vessels nor the sugar‐transporting sieve tube cells are capable of lengthening after differentiation. However, the vascular bundles in palms form a spiral within the stem and could theoretically lengthen if the spiral “straightened”.• Methods: We marked stretches of internodes on small and medium‐sized palms and measured their lengths over 2 years. Additionally, we collected material from small palms with short internodes and large palms with long internodes and made cross sections to determine the angle of vascular bundles within stems.• Key results: We found that stems lengthened (up to 12% over 2 years) below the apical meristem in small and medium‐sized palms and that the spiral angle in vascular bundles of small palms was significantly larger than at the base of large palms indicating a straightening of the spiral.• Conclusions: These results represent the first determination of “secondary lengthening” in tree stems as well as the most efficient method for height growth in terms of carbon investment. Likewise, elongation of stems allows palms to exhibit plasticity in height growth rates for more rapid growth when short‐lived canopy gaps are present than they would have with apical growth alone.
A SURVEY OF CORE MEDICAL TRAINEES’ OPINIONS ON THE EPORTFOLIO RECORD OF EDUCATIONAL ACTIVITIES: BENEFICIAL AND COST-EFFECTIVE?
Authors: Johnson S , Cai A , Riley P , Millar LM , McConkey H , Bannister C 
Published: March 2012

Objectives: To evaluate Core Medical Trainees’ (CMTs) opinions on the role of the ePortfolio in postgraduate education. Design and setting: Cross-sectional survey of 91 CMTs in five NHS trusts within the South Thames Deanery. Participants: Completed surveys were received from 80 Core Medical Trainees. Results: A total of 84% agreed that an ongoing record of progress is necessary, only 5% felt the ePortfolio represents value for money; 78% of respondents were unclear as to how the Freedom of Information Act (2000) impacts on the ePortfolio, and most were uninformed of the extent to which their entries can be accessed by third parties. Conclusions: Trainees recognise the importance of recording ongoing progress, but most consider the ePortfolio to be poor value for money. There is uncertainty regarding ownership of information held on ePortfolio, and to what extent it can be accessed. There are inadequate opportunities to discuss concerns. This requires further deliberation and until things are clarified, trainees may not fully engage with the resource.
Radical Thiol–XClick Chemistry
Authors: Brummelhuis Niels ten , Schlaad Helmut 
Published: March 2012

AbstractRadical thiol–ene and thiol–yne chemistry, that is, the free‐radical addition of thiols to unsaturated carbon–carbon bonds, has over the last decade developed into a powerful tool in the synthesis of numerous different materials, not in the least since this chemistry can possess the characteristics of a “click” reaction but because it is modular, achieves high yields in a short time, is selective toward a single product, and products are easy to purify. These characteristics are of great advantage in organic chemistry as, for instance, shown for the synthesis of bioactive molecules (glycoclusters and glycopeptides) and dendrimers, but also for the synthesis and modification of macromolecules, by step‐growth polymerization of multifunctional enes and thiols, respectively, and the addition of thiols to macromolecules bearing unsaturated groups (or vice versa). Another upcoming application is the modification of nanoparticles and surfaces, for which free‐radical thiol addition is supremely suitable because of its high yields and especially by the ease with which patterning of surfaces can be performed by using photochemical generation of free radicals.
Who is stressed? Comparing cortisol levels between individuals
Authors: Nepomnaschy Pablo A. , Lee Terry C.K. , Zeng Leilei , Dean C.B. 
Published: March 2012

AbstractCortisol is the most commonly used biomarker to compare physiological stress between individuals. Its use, however, is frequently inappropriate. Basal cortisol production varies markedly between individuals. Yet, in naturalistic studies that variation is often ignored, potentially leading to important biases.Objectives:Identify appropriate analytical tools to compare cortisol across individuals and outline simple simulation procedures for determining the number of measurements required to apply those methods.Methods:We evaluate and compare three alternative methods (raw values, Z‐scores, and sample percentiles) to rank individuals according to their cortisol levels. We apply each of these methods to first morning urinary cortisol data collected thrice weekly from 14 cycling Mayan Kaqchiquel women. We also outline a simple simulation to estimate appropriate sample sizes.Results:Cortisol values varied substantially across women (ranges: means: 1.9–2.7; medians: 1.9–2.8; SD: 0.26–0.49) as did their individual distributions. Cortisol values within women were uncorrelated. The accuracy of the rankings obtained using the Z‐scores and sample percentiles was similar, and both were superior to those obtained using the cross‐sectional cortisol values. Given the interindividual variation observed in our population, 10–15 cortisol measurements per participant provide an acceptable degree of accuracy for across‐women comparisons.Conclusions:The use of single raw cortisol values is inadequate to compare physiological stress levels across individuals. If the distributions of individuals' cortisol values are approximately normal, then the standardized ranking method is most appropriate; otherwise, the sample percentile method is advised. These methods may be applied to compare stress levels across individuals in other populations and species. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Design of a Fixed‐Order RST Controller for Interval Systems: Application to the Control of Piezoelectric Actuators
Authors: Khadraoui Sofiane , Rakotondrabe Micky , Lutz Philippe 
Published: March 2012

AbstractThis paper presents a technique for designing a robust polynomial RST controller for parametric uncertain systems. The uncertain parameters are assumed to be bounded by intervals. The computation of the controller is addressed by introducing the interval arithmetic. The controller synthesis is formulated as a set inversion problem that can be solved using the SIVIA algorithm. The proposed method is afterwards applied to design a robust controller for a piezoelectric microactuator. The experimental results show the efficiency of the proposed method. Finally, a fine stability analysis is performed to analytically prove the robustness of the designed controller.
Ethynyl Benziodoxolones for the Direct Alkynylation of Heterocycles: Structural Requirement, Improved Procedure for Pyrroles, and Insights into the Mechanism
Authors: Brand Jonathan P. , Chevalley Clara , Scopelliti Rosario , Waser Jérôme 
Published: March 2012

AbstractThis report describes a full study of the gold‐catalyzed direct alkynylation of indoles, pyrroles, and thiophenes using alkynyl hypervalent iodine reagents, especially the study of the structural requirements of alkynyl benziodoxolones for an efficient acetylene transfer to heterocycles. An improved procedure for the alkynylation of pyrroles using pyridine as additive is also reported. Nineteen alkynyl benziodoxol(on)es were synthesized and evaluated in the direct alkynylation of indoles and/or thiophenes. Bulky silyl groups as acetylene substituents were optimal. Nevertheless, transfer of aromatic acetylenes to thiophene was achieved for the first time. An accelerating effect of a methyl substituent in both the 3‐ and 6‐position of triisopropylsilylethynyl‐1,2‐benziodoxol‐3(1H)‐one (TIPS‐EBX) on the reaction rate was observed. Competitive experiments between substrates of different nucleophilicity, deuterium labeling experiments, as well as the regioselectivity observed are all in agreement with electrophilic aromatic substitution. Gold(III) 2‐pyridinecarboxylate dichloride was also an efficient catalyst for the reaction. Investigations indicated that gold(III) could be eventually reduced to gold(I) during the process. As a result of these investigations, a π activation or an oxidative mechanism are most probable for the alkynylation reaction.
The Importance of the trans‐Enamine Intermediate as a β‐Lactamase Inhibition Strategy Probed in Inhibitor‐Resistant SHV β‐Lactamase Variants
Authors: Ke Wei , Rodkey Elizabeth A. , Sampson Jared M. , Skalweit Marion J. , Sheri Anjaneyulu , Pagadala Sundar Ram Reddy , Nottingham Michael D. , Buynak John D. , Bonomo Robert A. , van den Akker Focco 
Published: March 2012

AbstractThe ability of bacteria to express inhibitor‐resistant (IR) β‐lactamases is stimulating the development of novel inhibitors of these enzymes. The 2′β‐glutaroxypenicillinate sulfone, SA2‐13, was previously designed to enhance the stabilization of the deacylation‐refractory, trans‐enamine inhibitory intermediate. To test whether this mode of inhibition can overcome different IR mutations, we determined the binding mode of SA2‐13 through X‐ray crystallography, obtaining co‐crystals of the inhibitor–protein complex by soaking crystals of the IR sulfhydryl variable (SHV) β‐lactamase variants S130G and M69V with the inhibitor. The 1.45 Å crystal structure of the S130G SHV:SA2‐13 complex reveals that SA2‐13 is still able to form the stable trans‐enamine intermediate similar to the wild‐type complex structure, yet with its carboxyl linker shifted deeper into the active site in the space vacated by the S130G mutation. In contrast, data from crystals of the M69V SHV:SA2‐13 complex at 1.3 Å did not reveal clear inhibitor density indicating that this IR variant disfavors the trans‐enamine conformation, likely due to a subtle shift in A237.