bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Climatological Comparison of Radar and Ground Observations of Hail in Finland
Authors: Saltikoff Elena , Tuovinen Jari-Petteri , Kotro Janne , Kuitunen Timo , Hohti Harri 
Published: September 2009

Abstract
Two approaches to producing a hail climatology for Finland are compared. The first approach is based on 70 yr of hail reports from different sources (newspapers, storm spotters, and other volunteers). The second is derived primarily from radar data. It is shown that a selection of newspaper articles of hail damage covering a period of 70 yr provides a good overview of the typical monthly and diurnal distribution of hail occurrence over the country. Radar data covering five summers (2001–05) provide another data source, but with different potential sources of errors. The two distinct methods compared in this paper give roughly the same results in describing the hail climatology of Finland, which gives additional confidence in each of the methods. On the basis of both methods, most hailstones are observed in the afternoon, 1400–1600 local time. The hail “season” extends from May to early September with maximum occurrences in June, July, and August. This means that hail is most frequently observed when the convective energy available for storm growth is at its diurnal or seasonal peak. The length of the hail season is the same according to both radar and newspaper data. The main difference emerges in relation to July and August events: 37% of news about hail events is published in newspapers in late July but only 8% in early August, whereas for radar data the numbers are more evenly distributed, 33% and 18%, respectively. This can be partially explained by sociological factors—July is the main holiday month in Finland, when outdoor activities in more remote areas are more popular.
Objective Satellite-Based Detection of Overshooting Tops Using Infrared Window Channel Brightness Temperature Gradients
Authors: Bedka Kristopher , Brunner Jason , Dworak Richard , Feltz Wayne , Otkin Jason , Greenwald Thomas 
Published: September 2009

Abstract
Deep convective storms with overshooting tops (OTs) are capable of producing hazardous weather conditions such as aviation turbulence, frequent lightning, heavy rainfall, large hail, damaging wind, and tornadoes. This paper presents a new objective infrared-only satellite OT detection method called infrared window (IRW)-texture. This method uses a combination of 1) infrared window channel brightness temperature (BT) gradients, 2) an NWP tropopause temperature forecast, and 3) OT size and BT criteria defined through analysis of 450 thunderstorm events within 1-km Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) imagery. Qualitative validation of the IRW-texture and the well-documented water vapor (WV) minus IRW BT difference (BTD) technique is performed using visible channel imagery, CloudSat Cloud Profiling Radar, and/or Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud-top height for selected cases. Quantitative validation of these two techniques is obtained though comparison with OT detections from synthetic satellite imagery derived from a cloud-resolving NWP simulation. The results show that the IRW-texture method false-alarm rate ranges from 4.2% to 38.8%, depending upon the magnitude of the overshooting and algorithm quality control settings. The results also show that this method offers a significant improvement over the WV-IRW BTD technique. A 5-yr Geosynchronous Operational Environmental Satellite (GOES)-12 OT climatology shows that OTs occur frequently over the Gulf Stream and Great Plains during the nighttime hours, which underscores the importance of using a day/night infrared-only detection algorithm. GOES-12 OT detections are compared with objective Eddy Dissipation Rate Turbulence and National Lightning Detection Network observations to show the strong relationship among OTs, aviation turbulence, and cloud-to-ground lightning activity.
A Hybrid Bulk–Bin Approach to Model Warm-Rain Processes
Authors: Grabowski Wojciech W. , Thouron Odile , Pinty Jean-Pierre , Brenguier Jean-Louis 
Published: September 2009

Abstract
This paper presents a hybrid approach to model warm-rain processes, merging the diverse schemes of bulk and detailed (bin) microphysics. In the bulk scheme, the key assumption is that the exact saturation is maintained inside a cloud. In contrast, the supersaturation inside a cloud is predicted in the bin scheme and is applied to calculate the diffusional growth of cloud droplets. Predicting the supersaturation is numerically cumbersome, however, and typically requires spatial and temporal resolutions that are significantly higher than those that can be applied in the bulk scheme. At the same time, supersaturations inside clouds are small, and the condensate amounts in bulk and bin schemes differ insignificantly. This critical observation forms a starting point for the hybrid bulk–bin approach. In this approach, when the cloud water first appears, the activation scheme inserts cloud droplets at the low end of the bin representation. Subsequent diffusional and eventually accretional growth shift the spectrum toward larger sizes so that the saturation inside a cloud is maintained. Details of the hybrid approach are discussed in this paper, and the validation against the traditional bin scheme in a framework of the adiabatic rising parcel is presented.
Before the scheme can be applied to the multidimensional cloud model, a 1D advection–condensation problem of Grabowski and Smolarkiewicz is used to address the issue of the numerical difficulties that finite-difference schemes experience near cloud edges. In the bulk case, these are in the form of condensation rate overshoots and undershoots; and this aspect requires special attention in the hybrid scheme. A novel approach is developed that provides a physically consistent solution near cloud edges using the hybrid bulk–bin scheme. The key is to allow grid boxes near the edges to be partly cloudy and to include spectral changes of cloud droplets that take this into account. Application of the hybrid scheme to an idealized 2D problem of moist thermal rising from rest and producing rain illustrates the application of the scheme to practical problems of cloud dynamics and warm-rain microphysics.
Do Undiluted Convective Plumes Exist in the Upper Tropical Troposphere?
Authors: Romps David M. , Kuang Zhiming 
Published: September 2009

AbstractUsing a passive tracer, entrainment is studied in cloud-resolving simulations of deep convection in radiative–convective equilibrium. It is found that the convective flux of undiluted parcels decays with height exponentially, indicating a constant probability per vertical distance of mixing with environmental air. This probability per distance is sufficiently large that undiluted updrafts are negligible above a height of 4–5 km and virtually absent above 10 km. These results are shown to be independent of the horizontal grid size within the range of 3.2 km to 100 m. Plumes that do reach the tropopause are found to be highly diluted.An equivalent potential temperature is defined that is exactly conserved for all reversible adiabatic transformations, including those with ice. Using this conserved variable, it is shown that the latent heat of fusion (from both freezing and deposition) causes only a small increase in the level of neutral buoyancy near the tropopause. In fact, when taken to sufficiently low pressures, a parcel with an ice phase ends up colder than it would without an ice phase. Nevertheless, the contribution from fusion to a parcel’s kinetic energy is quite large.Using an ensemble of tracers, information is encoded in parcels at the cloud base and decoded where the parcel is observed in the free troposphere. Using this technique, clouds at the tropopause are diagnosed for their cloud-base temperature, specific humidity, and vertical velocity. Using these as the initial values for a Lagrangian parcel model, it is shown that fusion provides the kinetic energy required for diluted parcels to reach the tropopause.
Increasing Trend of Synoptic Activity and Its Relationship with Extreme Rain Events over Central India
Authors: Ajayamohan R. S. , Merryfield William J. , Kharin Viatcheslav V. 
Published: September 2009

Abstract
The nature of the increasing frequency of extreme rainfall events (ERE) in central India is investigated by relating their occurrence to synoptic activity. Using a long record of the paths and intensities of monsoon synoptic disturbances, a synoptic activity index (SAI) is defined whose interannual variation correlates strongly with that in the number of ERE, demonstrating a strong connection between these phenomena. SAI furthermore shows a rising trend that is statistically indistinguishable from that in ERE, indicating that the increasing frequency of ERE is likely attributable to a rising trend in synoptic activity. This synoptic activity increase results from a rising trend in relatively weak low pressure systems (LPS), and it outweighs a declining trend in stronger LPS.
Dynamic Enthalpy, Conservative Temperature, and the Seawater Boussinesq Approximation
Authors: Young William R. 
Published: September 2009

AbstractA new seawater Boussinesq system is introduced, and it is shown that this approximation to the equations of motion of a compressible binary solution has an energy conservation law that is a consistent approximation to the Bernoulli equation of the full system. The seawater Boussinesq approximation simplifies the mass conservation equation to ∇ · u = 0, employs the nonlinear equation of state of seawater to obtain the buoyancy force, and uses the conservative temperature introduced by McDougall as a thermal variable. The conserved energy consists of the kinetic energy plus the Boussinesq dynamic enthalpy h‡, which is the integral of the buoyancy with respect to geopotential height Z at a fixed conservative temperature and salinity. In the Boussinesq approximation, the full specific enthalpy h is the sum of four terms: McDougall’s potential enthalpy, minus the geopotential g0Z, plus the Boussinesq dynamic enthalpy h‡, and plus the dynamic pressure. The seawater Boussinesq approximation removes the large and dynamically inert contributions to h, and it reveals the important conversions between kinetic energy and h‡.
Predictability of the Performance of an Ensemble Forecast System: Predictability of the Space of Uncertainties
Authors: Satterfield Elizabeth , Szunyogh Istvan 
Published: September 2009

Abstract
The performance of an ensemble prediction system is inherently flow dependent. This paper investigates the flow dependence of the ensemble performance with the help of linear diagnostics applied to the ensemble perturbations in a small local neighborhood of each model gridpoint location ℓ. A local error covariance matrix 𝗣ℓ is defined for each local region, and the diagnostics are applied to the linear space defined by the range of the ensemble-based estimate of 𝗣ℓ. The particular diagnostics are chosen to help investigate the efficiency of in capturing the space of analysis and forecast uncertainties.
Numerical experiments are carried out with an implementation of the local ensemble transform Kalman filter (LETKF) data assimilation system on a reduced-resolution [T62 and 28 vertical levels (T62L28)] version of the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS). Both simulated observations under the perfect model scenario and observations of the real atmosphere in a realistic setting are used in these experiments. It is found that (i) paradoxically, the linear space provides an increasingly better estimate of the space of forecast uncertainties as the time evolution of the ensemble perturbations becomes more nonlinear with increasing forecast time; (ii) provides a more reliable linear representation of the space of forecast uncertainties for cases of more rapid error growth (i.e., for cases of lower predictability); and (iii) the ensemble dimension (E dimension) is a reliable predictor of the performance of in predicting the space of forecast uncertainties.
Synthesis and Transport Activities of HIV–Tat Peptide-modified Cholesterol Pullulan
Authors: Kimura Aki , Kamo Yosuke , Takashima Yuuki , Kanazawa Takanori , Okada Hiroaki , Fukuda Tsunehiko 
Published: September 2009

Abstract
A complex in which the cell-penetrating peptide HIV–Tat and cholesterol pullulan were conjugated through a disulfide bond was synthesized. The complex showed marked cell penetrating activities as a vector.
Speed-up of Ab Initio Hybrid Monte Carlo and Ab Initio Path Integral Hybrid Monte Carlo Simulations by Using an Auxiliary Potential Energy Surface
Authors: Nakayama Akira , Taketsugu Tetsuya , Shiga Motoyuki 
Published: September 2009

Abstract
Efficiency of the ab initio hybrid Monte Carlo and ab initio path integral hybrid Monte Carlo methods is enhanced by employing an auxiliary potential energy surface that is used to update the system configuration via molecular dynamics scheme. As a simple illustration of this method, a dual-level approach is introduced where potential energy gradients are evaluated by computationally less expensive ab initio electronic structure methods.
Cytotoxic Evaluation of Ag@TiO2 Core–Shell Composite Nanoclusters against Cancer Cells
Authors: Abdulla-Al-Mamun Md , Kusumoto Yoshihumi , Islam Md Shariful 
Published: September 2009

Abstract
A Ag metal core–TiO2 shell (Ag@TiO2) composite nanocluster photocatalyst with uniform size and shape was successfully synthesized by a new simple citrate reduction method. The cytotoxicity of colloidal Ag@TiO2 composite nanoclusters was evaluated against cancer (HeLa) cells under UV–vis irradiation. Ag@TiO2 composite nanoclusters were characterized by using UV–vis absorption spectroscopy, TEM, SEM, XPS, XRD, and EDX techniques. It was found that Ag@TiO2 nanoclusters at low concentrations kill HeLa cells by 100%, whereas TiO2 nanoparticles alone kill only ca. 30% at the same concentrations.
Unusual Shapes of C60 Crystals Formed at Liquid–Liquid Interfaces
Authors: Yan Hu , Kagata Tsubasa , Uchida Takuya , Uematsu Takayuki , Iriyama Yu , Okuzaki Hidenori 
Published: September 2009

Abstract
We have found some unusually shaped C60 crystals which formed at liquid–liquid interfaces when m-xylene and ethanol were used as good and poor solvents, respectively. The crystals coexisted with large amounts of needle-like or whisker-like crystals which likely form at the initial stage of mixing the two solvents, probably indicating that this system follows Ostwald rule of stages like well-studied isoxazolone dye which has two polymorphs, i.e., the least stable needle-like one with a small size and the most stable rhombic crystal with a large size.
Obesity and health‐related quality of life: Does social support moderate existing associations?
Authors: Wiczinski Eileen , Döring Angela , John Jürgen , von Lengerke Thomas ,   For the KORA Study Group
Published: September 2009

Objectives Obesity has been shown to be negatively related to physical health‐related quality of life (HQOL) much more strongly than mental HQOL. This is remarkable given findings on obesity‐related social stigmata and associations with depression. Considering obesity as a stressor, this study tests for a moderating role of social support for obesity/HQOL associations among women and men.Design Data come from N=2,732 participants aged 35–74 years in a 2004–2005 general population survey in the Augsburg region, Germany.Methods Body weight and height were assessed by anthropometric measurements (classified by body mass index using WHO standards), social support by the Social Support Questionnaire 14‐item Short‐Form (F‐SozU‐K14) and HQOL by the 12‐item Short‐Form Health Survey (SF‐12). In multiple regression and general linear models, age, education, family status, health insurance, and place of residence were adjusted for.Results Among both genders, obesity was associated with reduced physical but not mental HQOL. Among men reporting strong social support, physical HQOL was impaired neither in the moderately nor the severely obese group (compared with normal weight), while it was given less social support. Among women, poor physical HQOL was associated with obesity regardless of social support.Conclusions In this adult population sample, no association was found for obesity with mental HQOL. In contrast, a negative association with physical HQOL exists for all subgroups except men with strong social support, indicating that social support buffers obesity‐related impairments in physical HQOL in men but not in women. This suggests that obese women and men with strong social support represent distinct populations, with possible implications for obesity care.
Creep and Recovery of A Zirconium-Tin-Columbium Alloy
Authors: Lubahn JD 
Published: September 2009

The creep characteristics of a 2Sn-2Cb zirconium alloy are expressed as a function of impurity content, heat treatment, and testing temperature, and the effects of these variables are described.
At the lower testing temperatures the creep behavior at constant stress and temperature conforms to the simple equation: ε=Bta where ε is creep strain, t is time, and B and a are constants. At higher temperatures the creep behavior can be described if the simple equation above is modified to take account of recovery. The observed variation of creep rate can be explained by recovery concepts only if the recovery rate depends on the strain level in addition to the strength level.
Laboratory Testing and the Hurability of Concrete
Authors: Kennedy TB 
Published: September 2009

Concrete structures cannot be constructed and subjected to full-scale tests for durability in a manner analogous to load tests. It therefore is necessary to estimate the durability of concrete structures by combining information gained from a study of service yielded by existing structures, controlled exposure tests of specimens, laboratory simulated-service tests, and tests and analyses of concrete and concrete materials. None of these sources of information provide a basis for adequately evaluating the effect on durability of workmanship, honesty, and intelligence that may or may not be employed in all stages of the operation from production of concrete materials to maintenance of the completed structure.
Durability of concrete structures is determined by materials, workmanship, design, and exposure. Petrographic examination of aggregates, X-ray diffraction studies of cement, freezing-and-thawing tests of concrete both in the laboratory and at field exposure stations, ultrasonic pulse velocity tests of specimens and structures, are recommended means of improving knowledge of durability of concrete and concrete structures.
Trace Analysis by Means of the Graphite Spark
Authors: Morris JM , Pink FX 
Published: September 2009

A combined method for the determination of trace elements is described. Chemical separation and concentration of the impurities is followed with spectrographic analysis by means of the graphite spark.
The method based on synthetic standards has been applied successfully to the determination of parts per billion quantities in semi-conductor materials.
An outline of the chemical concent rational procedures is given. The spec-trographic techniques of the graphite spark method are described and the excitation conditions, the line pairs, and the sensitivities are listed.
Correlation Between Rheological Parameters Measured in Instruments of Different Geometries
Authors: Brodnyan J. G. , Gaskins F. H. , Philippoff W. 
Published: September 2009

Treatments of the experimental data necessary to obtain the fundamental rheological parameters stress, strain, and rate of strain are presented, and some typical viscometers used to obtain flow data under steady-state conditions are described. With proper evaluation of the data, the same parameters are obtained independently of design and irrespective of whether the material exhibits Newtonian or non-Newtonian flow. As examples, flow curves are shown for such diverse materials as ASTM 103 oil, an 11 per cent solution of ethyl cellulose in cyclohexanone, a viscose solution, and five solutions of different concentrations of nitrocellulose in n-butyl acetate.
The manner in which elastic effects such as the normal stresses may be bserved in the various steady-state instruments is explained. Then, by examples, it is shown that such effects are not only quite large at high shearing stresses but may also be correlated independently of instrument. The examples used are five solutions of nitrocellulose in n-butyl acetate and seven solutions of different concentrations of polyisobutylene in Decalin.
An Investigation of Low-Temperature Viscosity Characteristics of Motor Oils
Authors: Kohl G. A. , Skoglund R. D. 
Published: September 2009

This paper presents viscosity data obtained on three Newtonian oils (ASTM Low-Temperature Reference Oils Nos. 1, 3, and 4) and two multigraded oils (ASTM Low-Temperature Reference Oils 5 and 6). These data were obtained using: (1) a modification of the ASTM D 1092 pressure viscometer, (2) a highrate-of-shear rotational viscometer, and (3) kinematic and Brookfield viscometers. An engine equipped with a constant-speed drive and cranking-torque measuring device was also used to determine the viscosity of the multigrade oils by using the Newtonian oils for calibration.
The differences among the data obtained with the various viscometers, the extrapolated viscosity at 0°F obtained from the ASTM Viscosity Temperature Charts, and the viscosities measured in the engine are discussed. The significance of this information with respect to the present SAE Motor Oil Classification system is considered.
Pitting of Galvanized Steel in Controlled Clean Air Environments
Authors: Spence J. W. , Haynie F. H. 
Published: September 2009

Specimens of galvanized steel sheet were exposed to polluted and clean air in controlled environmental chambers having the capability to simulate diurnal conditions. Corrosion of the zinc films was essentially a linear function of time for each exposure condition. The range of weight losses for the polluted and clean air environments were unexpected approximately the same. However, uniform corrosion of the zinc occurred in the polluted exposures whereas pitting corrosion of the zinc was observed in the clean air exposures.
Scanning electron microscopy/microprobe analysis of the galvanized zinc surface was used to study the mechanism of initiation and propagation of pitting corrosion. Corrosion products were observed to localize and form a barrier that could accentuate an acidic condition within the pit. Pitting corrosion is thus accelerated by the difference in pH within and outside the pit. During the pollutant exposures pitting corrosion is prevented because the drastic difference in pH within and outside the pit. During the pollutant exposures pitting corrosion is prevented because the drastic difference in pH did not occur.