bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climatology of Storm Reports Relative to Upper-Level Jet Streaks
Authors: Clark Adam J. , Schaffer Christopher J. , Gallus William A. , Johnson-O’Mara Kaj 
Published: January 2009

Abstract
Using quasigeostrophic arguments and numerical simulations, past works have developed conceptual models of vertical circulations induced by linear and curved jet streaks. Because jet-induced vertical motion could influence the development of severe weather, these conceptual models, especially the “four quadrant” model for linear jet streaks, are often applied by operational forecasters. The present study examines the climatology of tornado, hail, and severe wind reports relative to upper-level jet streaks, along with temporal trends in storm report frequencies and changes in report distributions for different jet streak directions. In addition, composite fields (e.g., divergence, vertical velocity) are analyzed for jet streak regions to examine whether the fields correspond to what is expected from conceptual models of curved or linear jet streaks, and whether the fields help explain the storm report distributions.
During the period analyzed, 84% of storm reports were associated with upper-level jet streaks, with June–August having the lowest percentages. In March and April the left-exit quadrant had the most storm reports, while after April the right-entrance quadrant was associated with the most reports. Composites revealed that tornado and hail reports are concentrated in the jet-exit region along the major jet axis and in the right-entrance quadrant. Wind reports have similar maxima, but the right-entrance quadrant maximum is more pronounced. Upper-level composite divergence fields generally correspond to what would be expected from the four-quadrant model, but differences in the magnitudes of the vertical velocity between the quadrants and locations of divergent–convergent centers may have resulted from jet curvature. The maxima in the storm report distributions are not well collocated with the maxima in the upper-level divergence fields, but are much better collocated with low-level convergence maxima that exist in both exit regions and extend into the right-entrance region. Composites of divergence–convergence with linear, cyclonic, and anticyclonic jet streaks also generally matched conceptual models for curved jet streaks, and it was found that wind reports have a notable maximum in the right-entrance quadrant of both anticyclonic and linear jet streaks. Finally, it was found that the upper-level divergence and vertical velocity in all jet-quadrants have a tendency to decrease as jet streak directions shift from SSW to NNW.
A Facile and Expeditious Synthesis of Cryptosanguinolentines
Authors: Kumar Dalip , Kumar. N. Maruthi , Rao V S 
Published: January 2009

Abstract
A simple and efficient synthesis of naturally occurring cryptosanguinolentines is described. Neat reaction of easily accessible 1-methyl-1,2,3,4-tetrahydroquinolin-4-ones and aryl hydrazines in the presence of p-toluenesulfonic acid at 100 °C rapidly afforded cryptosanguinolentines in very good yields.
Fluorescence of Rhodamine 6G on Hydrotalcite —Possibility of Alcohol Sensing—
Authors: Takahashi Keiichi , Tajima Masahiro , Matsunaga Katsuji , Miura Hideaki 
Published: January 2009

Abstract
The fluorescence intensity of Rhodamine 6G (R6G) introduced on hydrotalcite by the rehydration method was determined to depend strongly on the alcohol vapor pressure, whereas that of R6G simply adsorbed on hydrotalcite had low dependence on the vapor pressure. The intensity decreased with an increase in pressure, and the change in intensity was reversible. The degree of change differed according to the alcohol used and seemed to be related to the saturated vapor pressure of the alcohols.
Parallel Electrosynthesis of N-Acyliminium Ion Equivalents Using Silica Gel-supported Piperidine
Authors: Tajima Toshiki , Nakajima Atsushi 
Published: January 2009

Abstract
Parallel anodic methoxylation of carbamates was successfully carried out to provide the corresponding α-methoxylated products as N-acyliminium ion equivalents in high to excellent yields using silica gel-supported piperidine (Si–piperidine).
Electrochemical Investigation of the Behavior of Solid-supported Bases in Aprotic Organic Solvents Using Anodic Oxidation of p-Methoxybenzyl Alcohol as a Model Reaction
Authors: Tajima Toshiki , Oba Rieko , Nakajima Atsushi 
Published: January 2009

Abstract
The behavior of solid-supported bases in aprotic organic solvents was investigated by cyclic voltammetry as well as preparative electrolyses using anodic oxidation of p-methoxybenzyl alcohol as a model reaction.
Photoinduced Oxyamination of Enamines and Aldehydes with TEMPO Catalyzed by [Ru(bpy)3]2+
Authors: Koike Takashi , Akita Munetaka 
Published: January 2009

Abstract
Tris(bipyridyl)ruthenium(II) ([Ru(bpy)3]2+: TB(II)) catalyzes oxidative coupling of enamines and aldehydes with 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) under irradiation of visible light to afford α-oxyaminated carbonyl compounds. The visible light irradiation is essential to generate the triplet excited state of ∗TB(II) which acts as an oxidizing agent. This is a new procedure for radical coupling based on single electron transfer mediated by photoactivated TB.
A New Family of Ty1-copia-Like Retrotransposons Originated in the Tomato Genome by a Recent Horizontal Transfer Event
Authors: Cheng Xudong , Zhang Dongfeng , Cheng Zhukuan , Keller Beat , Ling Hong-Qing 
Published: January 2009

AbstractRider is a novel and recently active Ty1-copia-like retrotransposon isolated from the T3238fer mutant of tomato. Structurally, it is delimited by a duplication of target sites and contains two long terminal direct repeats and an internal open reading frame, which encodes a Ty1-copia-type polyprotein with characteristic protein domains required for retrotransposition. The family of Rider elements has an intermediate copy number and is scattered in the chromosomes of tomato. Rider family members in the tomato genome share high sequence similarity, but different structural groups were identified (full-size elements, deletion derivatives, and solo LTRs). Southern blot analysis in Solanaceae species showed that Rider was a Lycopersicon-specific element. Sequence analysis revealed that among other plants, two Arabidopsis elements (named as Rider-like 1 and Rider-like 2) are most similar to Rider in both the coding and noncoding regions. RT–PCR analysis indicates that Rider is constitutively expressed in tomato plants. The phylogeny-based parsimony analysis and the sequence substitution analyses of these data suggest that these Rider-like elements originated from a recent introgression of Rider into the tomato genome by horizontal transfer 1–6 million years ago. Considering its transcriptional activity and the recent insertion of the element into at least two genes, Rider is a recently active retrotransposon in the tomato genome.
Stress and Rock Property Profiling for Unconventional Reservoir Stimulation
Authors: Barree R. D. , Gilbert J. V. , Conway M. W. 
Published: January 2009

Abstract
Sonic log data and core measurements are often used to develop models of in-situ stress profiles and rock elastic properties for use in hydraulic fracture design treatments in unconventional reservoirs. &quot;Unconventional?? reservoirs, for the purposes of this paper, include shale-gas, coalbed methane, and tight-gas projects. In unconventional reservoirs, many of the assumptions underlying rock property estimation and stress profiling in conventional reservoirs may not apply. In fact, the result of using conventional approaches may be an incorrect and often misleading stress profile. Fracture geometry predicted using conventionally derived rock properties and stresses might also be inaccurate.
Methods of deriving rock properties from log and core measurements and the effect of various parameters on resulting moduli and stress estimates are examined. The paper also discusses the effects of rock anisotropy and inhomogeneity on static and dynamic properties. The impact of organic materials and trapped gas on sonic logs and conventional mechanical properties interpretation and the use of synthetic sonic logs are also presented. For static and dynamic measurements on core samples, the effects of the condition of recovered core and applied laboratory procedures on measurement results are also considered.
Potential errors resulting from the use of inappropriate mechanical properties for stress profiling and fracture geometry prediction can be significant. The paper identifies common pitfalls in core and log interpretation. A recommended procedure to determine useful and accurate rock mechanical properties for stress profile prediction and fracture design is presented.
Proppant Transport of Fracturing Gels is Influenced by Proppant Type
Authors: Harris Phillip C. , Heath Stanley J. 
Published: January 2009

Abstract
Fracturing gels are formulated to have a high viscosity sufficient to generate fracture geometry and transport proppant materials. Fracturing fluids are subjected to extensive QA/QC testing on high-temperature rheometers to ensure they have adequate viscosity to perform the intended task and break within a time frame suitable for the operation performed. Although most rheological tests incorporate only the gelled fluid without proppant materials, it is assumed that the fluid will transport proppants to their desired location.
A field location reported that treatments containing certain proppants were screening out more frequently. Tests were performed on a slurry viscometer (SV). It was discovered that not all proppant materials of the same nominal size and density were transported equally when added to a fracturing gel. The typical properties of the borate gels were measured, but no significant differences were found that would account for differences in transport. All the proppants had nominal 20/40 mesh size. A laser analysis of the particles indicated small differences in the distribution of sizes. However, the size analysis did not fit the trend that "bigger settles faster."
Scanning electron micrographs showed differences in surface roughness between the ceramic materials and sand. The proppants were coated with a tacky substance to neutralize any chemical absorption effects. The coated proppants then settled in a manner consistent with their physical characteristics (size and density), but the tacky material caused agglomeration and faster settling than before. The coated proppants were treated chemically to temporarily disable the tackiness, and it was observed that all the materials settled in a manner consistent with their physical characteristics.
It was found that certain 20/40-mesh proppants were suspended twice as long as other proppants in the same gel environment. The proppant effect was measured with the SV. The trend from the SV instrument correlated well with the screenout rate observed in the field.
Analysis indicated a surface catalytic effect of ceramic proppants causing faster decomposition of oxidizing breakers and accelerated gel breaking. This effect was absent in fluids with uncoated sand. Some resin-coated proppants were found to also accelerate breaking because of leaching of chemical compounds from the coatings.
Therefore, it is not correct to assume that all proppants added to fracturing gels will be transported equally. Viscosity measurements of gels without proppant might not give accurate information about the behavior of gels with proppant if the proppant interacts with the gels.
Optic Fiber Distributed Temperature for Fracture Stimulation Diagnostics and Well Performance Evaluation
Authors: Huckabee Paul 
Published: January 2009

Abstract
This paper summarizes applications of optic fiber (OF) distributed temperature sensing (DTS) technology for hydraulic fracturing stimulation diagnostics and well performance evaluation in unconventional gas well completions. Results are presented for temporary "call-out" deployments, velocity string installations, and permanent "behind casing" installations in vertical and horizontal wellbores. It is demonstrated that OF-DTS enables quantitative inflow distribution measurement for well performance evaluations in commingled multiple interval completions. OF-DTS is also shown to demonstrate the near wellbore dynamic placement characteristics during hydraulic fracture stimulation operations and, in one example, enables a superior volume distribution evaluation than radioactive (RA) tracer surveys. OF-DTS is demonstrated to be complimentary to RA tracer surveys in some cases. Additionally, this technology is being applied successfully for validation of hydraulic fracture containment in disposal well injection applications.
Propped Fracturing in High Temperature Deep Carbonate Formation
Authors: Li Yongping , Wang Yonghui , Cheng Xingsheng , Che Mingguang , Zhang Fuxiang , Peng Jianxin 
Published: January 2009

Abstract
Acid fracturing, as a conventional and effective stimulation method, has been widely used in carbonate formation. But because of serious acid leak-off and rapid acid/rock reaction speed, the length of effective acid etched fracture is always restricted, even the high viscosity acid and emulsified acid were applied; besides the effective duration of etched fracture was short, especially in deep well, because of the high closure stress acted on the fracture wall where the rock were softened significantly after contact with acid. In contrast, propped fracturing can create longer conductive fracture, and its effective duration is longer because the existence of proppant.
The carbonate reservoir are deeply buried (&gt;4500m) with high temperature (&gt;130°C), ultra-low porosity/permeability, high young's modulus and tensile strength, and the natural fractures often densely distributed in it, all of which makes the propped fracturing difficult. A new temperature-stability and shearing resistance delayed cross-linked guar fracturing fluid with low damage was developed to qualify for the fracturing treatment. Small size high strength ceramic proppant was selected to fulfill the narrow width of fracture, and proppant slugs was utilized to erode the tortuousness of near-wellbore fracture path and plug near-wellbore multiple hydraulic and natural fractures. The technology countermeasure ensured the success of propped fracturing treatment.
The net pressure and production history matching both indicated that the propped fracturing created longer conductive fracture and realized deep penetration. The well production increased dramatically after the stimulation. Besides, the comparison of production after gelled acid fracturing, surface cross-linked acid fracturing and propped fracturing in the same layer same well suggested that propped fracturing was more effective than the acid fracturing. The production test further showed propped fracturing could provide longer effective duration, and the well rate-maintenance capability was very excellent.
First Application of High Density Fracturing Fluid to Stimulate a High Pressure and High Temperature Tight Gas Producer Sandstone Formation of Saudi Arabia
Authors: Bartko K. , Arocha C. , Mukherjee T. S. , Sierra L. , Terracina J. , Lord P. 
Published: January 2009

Abstract
Recently Saudi Aramco and international companies started an aggressive gas exploration campaign in tight gas sandstone formations. In most of the cases the prospective tight gas producing zones were discovered at a depth below 20,000 feet where the stress and temperature are extremely high and the reservoir permeability conditions are low; being necessary in all cases to fracture stimulate each horizon to define the fluid and evaluate productivity.
The extreme stress and temperature conditions are actually one of the main challenges to perform fracture stimulations on this type of formation, this because the fracturing fluid needs to be stable, induce minimum damage and have good proppant transport capabilities at high temperature conditions.
As a part of the referenced exploration activity in the first quarter of 2008 Saudi Aramco has the challenge to perform a proppant fracture stimulation in a deep tight gas on shore sandstone formation where the temperature and stress conditions (375° F and 1.1 psi/ft at 20,000 feet) exceeded the working pressure capability of the available equipment and the existing fracturing fluids application limits. To answer the referenced challenges and knowing that 20,000 psi fracturing equipment is not available in the area an extensive laboratory evaluation was done to design a new high density fracturing fluid. After a lengthy laboratory evaluation, we were able to select a regional supplier for the 1.48 specific gravity (12.3 lb/gal) heavy brine used as the base fluid and prepare a user friendly cross linked fluid for the referenced field application. The new fluid system was successfully mixed and pumped in the field enabled the treatment of the well through lower surface treating pressure with conventional 15,000 psi equipment, lower horsepower requirements, and a safer work environment.
The paper summarizes the well conditions, extensive fluid qualification testing, procedures, and specially learned lessons during the referenced first field application of the new fracturing fluid system.
A Multi-Continuum Model for Gas Production in Tight Fractured Reservoirs
Authors: Wu Yu-Shu , Moridis George , Bai Baojun , Zhang Keni 
Published: January 2009

Abstract
Tight gas reservoirs are characterized by single-phase (gas) or two-phase (gas and liquid) flow in extremely low-permeability, highly heterogeneous porous/fractured, and stress-sensitive rock. Gas flow in such tight formations is further complicated by other co-existing processes, such as Klinkenberg effect, non-Newtonian or non-Darcy flow behavior, due to strong interaction between fluid molecules and solid materials within tiny pores, or micro- and macro- fractures. Because of the low permeability in tight rock, the traditional double-porosity model may not be applicable for handling fracture-matrix interaction of gas flow in these reservoirs. In this work, we present a generalized mathematical model for simulating multiphase flow of gas in tight, porous/fractured reservoirs using a more general, multi-continuum modeling approach. The model incorporates the following processes: (1) Klinkenberg effect, (2) non-Newtonian behavior (i.e., threshold pressure gradient for flow to occur); (3) non-Darcy flow with inertial effects; and (4) rock deformation due to changes in the stress field. We propose to explicitly separate effects of rock mechanical deformation and molecular interaction between fluids and rock materials. The former effect is included using the intrinsic permeability and porosity relations, while the latter is accounted for by an apparent viscosity for non-Newtonian, non-Darcy's behavior, or a modified permeability for Klinkenberg effect
The proposed mathematical model has been implemented into a multiphase, multidimensional reservoir simulator. In the numerical model, specifically, a control-volume, integral finite-difference method is used for spatial discretization with an unstructured grid, and a first-order finite-difference scheme is adapted for temporal discretization of governing two-phase flow equations in tight gas reservoirs. The resulting discrete nonlinear equations are solved fully implicitly by Newton iteration. The numerical scheme has been verified against analytical solutions with Klinkenburg effect, non-Newtonian or non-Darcy flow, and flow in deformable fractured rock in our previous studies. The model's application to actual tight gas reservoirs is an on-going research project.
Investigation of Flow Behavior of Slick-Water in Large Straight and Coiled Tubing
Authors: Shah S. N. , Kamel A. H. Ahmed 
Published: January 2009

Abstract
Low damage fracturing fluids are normally utilized for better fracture dimensions confinement and lower residue. This leads to not only longer fracture lengths, but also, higher fracture conductivity. Slick-water fracturing technology - developed in the 1980s - is less expensive than gel treatments. Fluid and proppant volumes can be reduced and treatment flow rates can be significantly increased. When compared to conventional gel treatments, slick-water fracturing can generate similar or better production responses.
In frac treatments, slick-water is pumped through straight as well as coiled tubing. As a result of secondary flow, friction pressure losses in CT are higher than in straight tubing. Determining these losses is of utmost importance for successful treatments. Customarily, laboratory generated flow data are used to develop correlations to predict friction pressure of fluids flowing in ST and CT. These correlations are then, without verification, applied to field application which employ much larger conduit sizes.
The present study is aimed to experimentally investigate the hydraulic properties of the commonly used drag reducer; Nalco ASP-820 in larger tubing sizes. It is a modified partially-hydrolyzed polyacrylamide, PHPA. Previously, we reported flow data gathered employing a ½-in. ST and CT (varying curvature ratio) and the correlations developed to predict friction losses of fluids in ST and CT. In this investigation, the large-scale flow data acquired from 200-ft ST and 1,000, 2,000, and 3,000-ft, 1½-in. CT, and 1,000-ft 2⅜- and 2⅞-in. CT are compared with the predictions from the correlations developed from ½-in. pipe data. The effects of shear intensity, shear duration, and pipe roughness on flow properties of ASP fluid are also investigated.
Results show significantly lower drag reduction in CT than in ST due to secondary flow caused by the tubing curvature. Polymer degradation because of shear (shear intensity and duration) and/or tubing roughness can significantly reduce drag reduction. The results are discussed in light of a recently developed "Drag Reduction Envelope" to evaluate the drag reduction characteristics of slick-water fluid in ST and CT.