bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coiled Tubing Friction in Extended-Reach Wells
Authors: Livescu Silviu , Craig Steven , Aitken Bill 
Published: February 2016

Abstract
The lateral reach and residual bottom hole assembly (BHA) loads in extended-reach wells strongly depend on the coiled tubing (CT) mechanical friction. Detailed CT friction modeling becomes crucial in the pre-job planning stage to ensure successful job predictability. However, current numerical simulators consider constant coefficients of friction (CoFs) that are determined from similar operations without taking into account the effects of the operational and downhole parameters on the CoF for a specific operation. This study outlines the modeling of CT friction force, CoF, and axial BHA loads depending on the operational and downhole parameters when a fluid hammer tool is used.
Recent theoretical, laboratory, and field data have established how CoF depends on the downhole parameters (Livescu and Watkins 2014; Livescu et al. 2014; Livescu and Craig 2015). Previously, these effects have not been considered in the CT numerical models, leading to significant CoF differences among available commercial simulators. For instance, the default CoFs in the current pre-job simulations for cased holes, when no lubricant or friction reducing tools such as fluid hammer tools and tractors are used, vary between 0.24 and 0.30 or even higher. This makes it extremely difficult to consistently evaluate and compare the friction reduction effects of lubricants, fluid hammer tools, and tractors in extended-reach wells, especially when the field operator may be consulting with several service companies utilizing different commercial force modelling software.
This study presents the CT force matching and fundamental physics based on modeled fluid forces, including radial forces, drag forces, and most importantly pressure forces on the CT friction forces due to fluid hammer tools. Extending the Method of Characteristics, regularly used for studying pressure pulses in straight pipes, the Perturbations Method also accounts for the helical shape of the CT. The new CT fluid hammer model is validated against laboratory data. This rigorous method for calculating the axial BHA load and reduced CT friction force due to radial vibrations can be easily implemented in currently available tubing force analysis (TFA) software for CT operations.
This novel approach, which uses detailed CT mechanical friction modeling to take into account parameters such as temperature, internal pressure, pumping rate, etc., improves predictions for CT reach in lateral wells. These findings broaden the current industry understanding of the CT mechanical friction modeling in extended-reach wells and show benefits for the industry when considering variable friction modeling in commercial CT simulators.
Operational Improvements with the Expansion of an Intelligent Coiled Tubing System to Include Real-Time Tension, Compression, and Torque Data Monitoring
Authors: Garner Louis , Vacik Lubos , Livescu Silviu , Blanco Diego 
Published: February 2016

Abstract
Real-time monitoring of downhole location, pressure, and temperature is currently available for many coiled tubing (CT) operations. A newly-developed tension, compression, and torque (TCT) data monitoring capability in real-time improves operational efficiency and accelerates well recovery in all types of CT operations. From milling, stimulation, and well cleanouts to gas lifting, camera services, logging and perforating operations, this intelligent coiled tubing (ICT) system can provide accurate, real-time downhole monitoring of high-resolution depth correlation, differential pressure and temperature, and TCT data.
The real-time ICT system consists of a 1/8-in. non-intrusive electrical conductor wire inside the carrying CT, surface hardware and software, and three versions of bottomhole assemblies (BHAs) in different sizes: 2 ⅛-, 2 ⅞-, and 3 ½-in. Each BHA incorporates a conductor release assembly, a casing collar locator (CCL), pressure, and temperature sensor package, and a BHA release function. In addition, a new TCT assembly has been developed for the 2 ⅞-in. BHA. Switching between applications is as simple as changing out the BHA, which reduces the need to rig-up and rig-down and leads to operational time and cost savings. The main advantage of this system is that it eliminates the downhole uncertainties so the CT field crew can react to changing conditions, making decisions based on dynamic downhole events and eliminating missed or wasted runs.
Several case studies have been recently presented (Livescu et al. 2015a,b) using the 2 ⅛-in. BHA. They involved ICT conveyed camera operations; complex cement milling, cleanout, and perforating operations; inflatable plug setting operations for water zone isolation; complex drifting, logging, jetting, zonal isolation, and scale removal operations; and matrix acidizing operations. In this paper the new TCT assembly development and testing are presented showing that combining the TCT data with location, pressure, and temperature data in real-time may increase the job efficiency and control. The new capabilities are important for the differentiation between frictional lock-up and potential obstruction tagging; the effectiveness of extended reach technologies such as fluid hammer tools, tractors, and lubricants related to the weight on bit (WOB); the confirmation of jar activation during fishing jobs; and the milling effectiveness over time, quantifying the mill aggressiveness from the back torque and WOB analysis. In addition, the new TCT data could be used to post-job validate in real-time the pre-job tubing force analysis (TFA).
Ecological study of periphyton diversity in crenic habitat of Sahashradhara (Garhwal Himalayas, India)
Authors: Chauhan Anita , Sharma Ramesh C. 
Published: February 2016

A maiden attempt has been made to present a biodiversity of periphyton of the Sahashradhara springs, a group of one thousand springs and one of the most important clusters of limnocrenes and rheocrenes springs located in Doon Valley of Garhwal-Himalayas. The environmental monitoring of periphyton community of Sahashradhara springs was carried out for one complete annual cycle (October 2011-September 2012). Annual percentage composition of periphyton revealed that major contribution was represented by Bacillariophyceae (68-70%) followed by Chlorophyceae (26-28%) and Myxophyceae (3-5%). A total of 29 species of periphyton were recorded from different springs of Sahashradhara. A significant correlation between diversity of periphyton and environmental parameters- temperature, turbidity, conductivity, dissolved oxygen, free CO2, alkalinity, FPOM and CPOM was observed. Regression analysis was performed between density of periphyton and physico-chemical variables, which revealed that temperature, conductivity, alkalinity, CO2, TDS, CPOM and FPOM were found to have strong influence on the density and diversity of periphyton of Sahashradhara springs.International Journal of Environment Vol. 5 (1) 2016, pp: 79-95
Comparison of goniometric measurements of the stifle joint in seven breeds of normal dogs
Authors: Ocal Mehmet , Sabanci Seyyid 
Published: February 2016

SummaryObjective: To compare the goniometric measurements of the stifle joint in seven dog breeds, and to determine the relationship among goniometric measurements, age, body weight, tibial plateau angle, crus and thigh circumferences, and widths of quadriceps, hamstring, and gastrocnemius muscles in healthy dogs.Methods: We used a total of 126 dogs from seven different breeds, and recorded the angle of the stifle joint at standing, extension, and flexion together with the range of motion (ROM). The circumferences of the thigh and crus were also measured. Medio -lateral radiographic projections of the tibia and the femur were obtained from the dogs, and the tibial plateau angles, as well as the widths of quadriceps, hamstring, and gas -trocnemius muscles, were measured from these images.Results: Neither the sex of the dog nor the differences in the side measured affected the goniometric measurements of the stifle joint. The standing, extension, flexion, and ROM angles were different among the breeds. The standard deviations of the standing and extension angles were small relative to their means, but the standard deviations of the flexion angle were large relative to their means in all breeds. Body weight and muscular measurements were the most influential factors on the stifle flexion angle and ROM.Clinical significance: Breed differences, body weights, and muscle mass should be taken into consideration during assessment of the stifle function using goniometric measurements.
Computed tomographic arthrography of the normal dromedary camel carpus
Authors: Marzok Mohamed , Eshra Eman , Badawy Adel 
Published: February 2016

SummaryThe aim of this prospective cadaveric study was to provide a detailed computed tomographic (CT) reference of the carpal joint in healthy dromedary camels. Twelve forelimbs of six apparently healthy camels were used. Computed tomographic imaging of 12 normal cadaveric camel carpal joints was performed before and after intra-articular administration of iodinated contrast medium. Transverse CT images were reconstructed in dorsal and parasagittal planes. The six carpal bones, the radial trochlea, and the proximal articular surface of the metacarpal bones were clearly visible on CT images with the bone setting window. Radiocarpal, carpometacarpal, transverse intercarpal, medial and lateral palmer intercarpal, middle intercarpal, accessory carpoulnar and medial and lateral collateral ligaments, carpal canal, joint capsule, and the extensor and flexor tendons were identified on CT images with the soft-tissue setting window. Postcontrast CT images provided better delineation of intercarpal ligaments, the capsular compartments and recesses. Results indicated that the osseous and the clinically important soft tissue structures of the dromedary camel carpal joint could be identified using CT and CT arthrography. The CT data of this study will serve as a basis for diagnosis of carpal problems in camels.
ASAS J083241+2332.4: A NEW EXTREME LOW MASS RATIO OVERCONTACT BINARY SYSTEM
Authors: Sriram K. , Malu S. , Choi C. S. , Vivekananda Rao P. 
Published: February 2016

ABSTRACT
We present the R- and V-band CCD photometry and Hα line studies of an overcontact binary ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O’Connell effect. The photometric solution indicates that this system falls into the category of extreme low-mass ratio overcontact binaries with a mass ratio, q ∼ 0.06. Although a trace of the O’ Connell effect is observed, constancy of the Hα line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O–C variations reveals that the period of the binary shows a secular increase at the rate of dP/dt ∼ 0.0765 s years−1, which is superimposed by a low, but significant, sinusoidal modulation with a period of ∼8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely low mass ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, q
critical = 0.07–0.09, overcontact binaries should merge and form a fast rotating star, but it has been suggested that q
critical can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%–70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L
2 is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.
GLOBAL MODELING OF NEBULAE WITH PARTICLE GROWTH, DRIFT, AND EVAPORATION FRONTS. I. METHODOLOGY AND TYPICAL RESULTS
Authors: Estrada Paul R. , Cuzzi Jeffrey N. , Morgan Demitri A. 
Published: February 2016

ABSTRACT
We model particle growth in a turbulent, viscously evolving protoplanetary nebula, incorporating sticking, bouncing, fragmentation, and mass transfer at high speeds. We treat small particles using a moments method and large particles using a traditional histogram binning, including a probability distribution function of collisional velocities. The fragmentation strength of the particles depends on their composition (icy aggregates are stronger than silicate aggregates). The particle opacity, which controls the nebula thermal structure, evolves as particles grow and mass redistributes. While growing, particles drift radially due to nebula headwind drag. Particles of different compositions evaporate at “evaporation fronts” (EFs) where the midplane temperature exceeds their respective evaporation temperatures. We track the vapor and solid phases of each component, accounting for advection and radial and vertical diffusion. We present characteristic results in evolutions lasting 2 × 105 years. In general, (1) mass is transferred from the outer to the inner nebula in significant amounts, creating radial concentrations of solids at EFs; (2) particle sizes are limited by a combination of fragmentation, bouncing, and drift; (3) “lucky” large particles never represent a significant amount of mass; and (4) restricted radial zones just outside each EF become compositionally enriched in the associated volatiles. We point out implications for millimeter to submillimeter SEDs and the inference of nebula mass, radial banding, the role of opacity on new mechanisms for generating turbulence, the enrichment of meteorites in heavy oxygen isotopes, variable and nonsolar redox conditions, the primary accretion of silicate and icy planetesimals, and the makeup of Jupiter’s core.
NONLINEAR COLOR–METALLICITY RELATIONS OF GLOBULAR CLUSTERS. VI. ON CALCIUM II TRIPLET BASED METALLICITIES OF GLOBULAR CLUSTERS IN EARLY-TYPE GALAXIES
Authors: Chung Chul , Yoon Suk-Jin , Lee Sang-Yoon , Lee Young-Wook 
Published: February 2016

ABSTRACT
The metallicity distribution function of globular clusters (GCs) in galaxies is a key to understanding galactic formation and evolution. The calcium II triplet (CaT) index has recently become a popular metal abundance indicator thanks to its sensitivity to GC metallicity. Here we revisit and assess the reliability of CaT as a metallicity indicator using our new stellar population synthesis simulations based on empirical high-resolution fluxes. The model shows that the CaT strength of old (>10 Gyr) GCs is proportional to [Fe/H] below −0.5. In the modest metal-rich regime, however, CaT does not increase anymore with [Fe/H] due to the little contribution from coolest red giant stars to the CaT absorption. The nonlinear nature of the color–CaT relation is confirmed by the observations of GCs in nearby early-type galaxies. This indicates that the CaT should be used carefully when deriving metallicities of metal-rich stellar populations. Our results offer an explanation for the observed sharp difference between the color and CaT distributions of GCs in the same galaxies. We take this as an analogy to the view that metallicity–color and metallicity–Lick index nonlinearity of GCs is primarily responsible for their observed “bimodal” distributions of colors and absorption indices.
CONVERGING SUPERGRANULAR FLOWS AND THE FORMATION OF CORONAL PLUMES
Authors: Wang Y.-M. , Warren H. P. , Muglach K. 
Published: February 2016

ABSTRACT
Earlier studies have suggested that coronal plumes are energized by magnetic reconnection between unipolar flux concentrations and nearby bipoles, even though magnetograms sometimes show very little minority-polarity flux near the footpoints of plumes. Here we use high-resolution extreme-ultraviolet (EUV) images and magnetograms from the Solar Dynamics Observatory (SDO) to clarify the relationship between plume emission and the underlying photospheric field. We find that plumes form where unipolar network elements inside coronal holes converge to form dense clumps, and fade as the clumps disperse again. The converging flows also carry internetwork fields of both polarities. Although the minority-polarity flux is sometimes barely visible in the magnetograms, the corresponding EUV images almost invariably show loop-like features in the core of the plumes, with the fine structure changing on timescales of minutes or less. We conclude that the SDO observations are consistent with a model in which plume emission originates from interchange reconnection in converging flows, with the plume lifetime being determined by the ∼1 day evolutionary timescale of the supergranular network. Furthermore, the presence of large EUV bright points and/or ephemeral regions is not a necessary precondition for the formation of plumes, which can be energized even by the weak, mixed-polarity internetwork fields swept up by converging flows.
LOFAR, VLA, AND CHANDRA OBSERVATIONS OF THE TOOTHBRUSH GALAXY CLUSTER
Authors: van Weeren R. J. , Brunetti G. , Brüggen M. , Andrade-Santos F. , Ogrean G. A. , Williams W. L. , Röttgering H. J. A. , Dawson W. A. , Forman W. R. , Gasperin F. de , Hardcastle M. J. , Jones C. , Miley G. K. , Rafferty D. A. , Rudnick L. , Sabater J. , Sarazin C. L. , Shimwell T. W. , Bonafede A. , Best P. N. , Bîrzan L. , Cassano R. , Chyży K. T. , Croston J. H. , Dijkema T. J. , Enßlin T. , Ferrari C. , Heald G. , Hoeft M. , Horellou C. , Jarvis M. J. , Kraft R. P. , Mevius M. , Intema H. T. , Murray S. S. , Orrú E. , Pizzo R. , Sridhar S. S. , Simionescu A. , Stroe A. , Tol S. van der , White G. J. 
Published: February 2016

ABSTRACT
We present deep LOFAR observations between 120 and 181 MHz of the “Toothbrush” (RX J0603.3+4214), a cluster that contains one of the brightest radio relic sources known. Our LOFAR observations exploit a new and novel calibration scheme to probe 10 times deeper than any previous study in this relatively unexplored part of the spectrum. The LOFAR observations, when combined with VLA, GMRT, and Chandra X-ray data, provide new information about the nature of cluster merger shocks and their role in re-accelerating relativistic particles. We derive a spectral index of

at the northern edge of the main radio relic, steepening toward the south to

. The spectral index of the radio halo is remarkably uniform (

, with an intrinsic scatter of

). The observed radio relic spectral index gives a Mach number of

, assuming diffusive shock acceleration. However, the gas density jump at the northern edge of the large radio relic implies a much weaker shock (

, with an upper limit of

). The discrepancy between the Mach numbers calculated from the radio and X-rays can be explained if either (i) the relic traces a complex shock surface along the line of sight, or (ii) if the radio relic emission is produced by a re-accelerated population of fossil particles from a radio galaxy. Our results highlight the need for additional theoretical work and numerical simulations of particle acceleration and re-acceleration at cluster merger shocks.
A chamber study of the influence of boreal BVOC emissions and sulfuric acid on nanoparticle formation rates at ambient concentrations
Authors: Dal Maso M. , Liao L. , Wildt J. , Kiendler-Scharr A. , Kleist E. , Tillmann R. , Sipilä M. , Hakala J. , Lehtipalo K. , Ehn M. , Kerminen V.-M. , Kulmala M. , Worsnop D. , Mentel T. 
Published: February 2016

Abstract. Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich plant–atmosphere simulation chamber with instrumentation for the detection of sulfuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulfuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOCs). We present direct laboratory observations of nanoparticle formation from sulfuric acid and realistic BVOC precursor vapour mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulfuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulfuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.
Retrieval of xCO2 from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON
Authors: Buschmann Matthias , Deutscher Nicholas M. , Sherlock Vanessa , Palm Mathias , Warneke Thorsten , Notholt Justus 
Published: February 2016

Abstract. High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO2 (denoted by xCO2). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average.
Pale halo surrounding a homogenous bluish-purplish central area: dermoscopic clue for eccrine hidrocystoma
Authors: Duman Nilay , Duman Deniz , Sahin Sedef 
Published: February 2016

Abstract
Eccrine hidrocystomas are benign tumors of the sweat glands that arise from cystic dilatation of the excretory sweat duct. Exact diagnosis requires biopsy and histopathologic examination, from which arises risk of scarring. Dermoscopy could be a useful tool in diagnosing eccrine hidrocystomas. Herein we aim to present dermoscopic features in three female patients with multiple lesions on the face consistent with eccrine hidrocystomas.