Linear Rate Of Increase Research Articles

High Milling Time Influence on the Phase Stability and Electrical Properties of Fe50Mn35Sn15 Heusler Alloy Obtained by Mechanical Alloying.

Fe50Mn35Sn15 Heusler alloy, obtained by mechanical alloying, was subjected to larger milling times in the range of 30-50 h to study the phase stability and morphology. X-ray diffraction studies have shown that the milled samples crystallise in a disordered A2 structure. The A2 structure was found to be stable in the milling range studied, contrary to the computation studies performed on this composition. Using Rietveld refinements, the lattice parameter, mean crystallite size, and lattice strain were computed. The nature of the obtained phases by milling was found to be nanocrystalline with values below 50 nm. A linear increase rate of 0.00713 (h-1) was computed for lattice strain as the milling time increased. As the milling time increases, the lattice parameter of the cubic Heusler was found to have a decreasing behaviour, reaching 2.9517 Å at 50 h of milling. The morphological and elemental distribution-characterised by scanning electron microscopy and energy-dispersive X-ray spectroscopy-evidenced Mn and Sn phase clustering. As the milling time increased, the morphology of the sample was found to change. The Mn and Sn cluster size was quantified by elemental line profile. Electrical resistivity evolution with milling time was analysed, showing a peak for 40 h of milling time.

Urinary continence following extraperitoneal radical prostatectomy: impact of surgical technique and pelvic fascial spaces reconstruction

Introduction. Urinary incontinence is a common complication of radical prostatectomy. The development of surgical techniques when performing radical prostatectomy that improve the function of urinary continence after surgery is actual.Objective. To compare urinary continence functions in long-term follow-up after open and laparoscopic radical prostatectomy when only posterior or combined (anterior + posterior) reconstruction of the pelvic fascial spaces is performed.Materials & methods. The study included 130 patients aged 63.0 [59.0; 68.0] years with local prostate cancer (сT1a-2сN0-xM0; 1 – 4 ISUP groups), subjected to non-nerve-sparing retropubic radical prostatectomy with posterior reconstruction and non-nerve-sparing extraperitoneal laparoscopic radical prostatectomy with isolated posterior or combined (anterior + posterior) fascial reconstruction of the pelvic fascial spaces. Postoperative continence function was studied at 1, 3, 6, and 12 months following surgery using a standard pad test.Results. The incidence of urinary continence was higher at all follow-up periods during laparoscopic surgery. From the 6-months follow-up, these patients did not have severe urinary incontinence. At the same time, the rate of growth of some patients who began to retain urine did not depend on the method of reconstruction of the pelvic fascial spaces. The use of combined reconstruction of the pelvic fascial spaces at 12-months follow-up showed an advantage in urinary continence over performing only posterior reconstruction. Such patients achieved urinary continence in 90% of cases compared to 80.0% of cases. At the same time, the restoration of urinary continence at all periods of observation had a relatively uniform linear rate of increase in the indicator.Conclusion. Reconstruction of the pelvic fascial spaces during open and laparoscopic radical prostatectomy allows one to achieve satisfactory continuation in the postoperative period. However, higher efficiency is achieved when using a combined reconstruction technique.

Topography prediction of high-aspect ratio features milled with overlapping abrasive slurry jet footprints considering fluid confinement effects

Overlapping adjacent passes of abrasive slurry jets can be used to fabricate micro-pockets or blind micro-slots. This study investigates the propagation of surfaces milled using overlapping passes of a high-pressure abrasive slurry jet on a ductile 6061-T6 target over a wide range of aspect ratios. Features such as shallow pockets with low aspect ratios to deep slots with aspect ratios ∼1.5 were fabricated to investigate the correlations between the aspect ratio, degree of pass overlap, and number of repeating passes with the machined surface evolution characteristics. A comprehensive model was presented that combined computational fluid dynamics (CFD) with surface evolution to predict the evolving machined feature topography after each of the overlapping and repeating passes, and to provide insights into experimental observations. The model explicitly considered the CFD-predicted local particle impact angles and velocities as well as effects due to secondary impacts, high sidewall slopes, and stagnation effects. For larger degrees of overlap, measurements revealed a more than linear rate of increase in depth after each repeat of two adjacent overlapped passes, as opposed to a linear depth increase for smaller overlaps and blind pockets. Large overlaps were found to result in asymmetric features. Up to a critical aspect ratio of ∼0.65, the model predicted the surface evolution of the features to within <8.6% of those measured. Beyond that, randomness in the machined feature shape and size made the process challenging to control and the surface evolution difficult to predict. Nevertheless, the model was able to elucidate the reasons for the randomness and other observed phenomena such as the more than linear growth in etch rate, and the occurrence of feature asymmetry. The findings emphasize that flow confinement, increases in the jet's turbulent kinetic energy, and the formation of vortices at the bottom of the machined features are critical factors influencing the machining process, and that in these cases explicit modeling approaches like the one presented in this study must be used.

Rapid loss of maternal immunity and increase in environmentally mediated antibody generation in urban gulls

Monitoring pathogen circulation in wildlife sentinel populations can help to understand and predict the spread of disease at the wildlife-livestock-human interface. Immobile young provide a useful target population for disease surveillance, since they can be easily captured for sampling and their levels of antibodies against infectious agents can provide an index of localized circulation. However, early-life immune responses include both maternally-derived antibodies and antibodies resulting from exposure to pathogens, and disentangling these two processes requires understanding their individual dynamics. We conducted an egg-swapping experiment in an urban-nesting sentinel seabird, the yellow-legged gull, and measured antibody levels against three pathogens of interest (avian influenza virus AIV, Toxoplasma gondii TOX, and infectious bronchitis virus IBV) across various life stages, throughout chick growth, and between nestlings raised by biological or non-biological parents. We found that levels of background circulation differed among pathogens, with AIV antibodies widely present across all life stages, TOX antibodies rarer, and IBV antibodies absent. Antibody titers declined steadily from adult through egg, nestling, and chick stages. For the two circulating pathogens, maternal antibodies declined exponentially after hatching at similar rates, but the rate of linear increase due to environmental exposure was significantly higher in the more prevalent pathogen (AIV). Differences in nestling antibody levels due to parental effects also persisted longer for AIV (25 days, vs. 14 days for TOX). Our results suggest that yellow-legged gulls can be a useful sentinel population of locally transmitted infectious agents, provided that chicks are sampled at ages when environmental exposure outweighs maternal effects.

Effects of Ion Content on the Ion Aggregation Morphology and Glass Transition of Poly(styrene-ran-cinnamic acid) (SCA) Zn-Salt Ionomer

Poly(styrene-ran-cinnamic acid) (SCA) Zn-salt ionomers (SCA‒Zn) bearing increasing contents (0, 0.23, 0.55, 1.3, 3.0, and 5.5 mol%) of Zn2+ ions were successfully synthesized by solution neutralization of the SCA with Zn2+ ions at room temperature. As the ion content of the SCA‒Zn increased from 0 to 5.5 mol%, the size and the aggregation number of the ionic aggregates did not change significantly, because the increase in ion content led to a monotonic increase in the number density of ionic aggregates, while the number of ions participating in the aggregates to form ionic aggregates was essentially fixed. Furthermore, the T g values of the SCA‒Zn increased slowly as the Zn2+ ion content increased, and the linear increase rate with Zn2+ ion content was ∼0.8 °C mol−1, which was quite different from the reported increase rate in the T g values of the matrix phase with Na+ ion content of 3–6 °C mol−1. This appeared to be caused by the steric hindrance effect of the adjacent groups of –COO− ions in the SCA and the long-distance electrostatic attraction. In addition, the degree of ionization of the SCA‒Zn was too low to cause large changes in thermal stability.

Effect of welan gum and nanoclay on thixotropy of UHPC

This study evaluates the effect of welan gum (WG) and nanoclay (NC) on thixotropy of ultra-high-performance concrete (UHPC) matrix made with 0.20 water-to-binder ratio. The mortar mixtures were proportioned with a fixed superplasticizer (SP) content and WG and NC contents varying between 0 and 0.09% and 0 and 0.4%, respectively. The dynamic yield stress of these mixtures varied from 40 to 170 Pa. Similarly, UHPC made with different WG and NC contents were prepared with variable SP dosages to maintain initial mini-slump flow of 200 ± 5 mm. Test results indicate that thixotropy can be enhanced by using WG or NC in UHPC with a fixed SP dosage. On the other hand, for UHPC made with variable SP, the incorporation of WG increased thixotropy, whereas the use of NC had limited contribution to thixotropy. Particle flocculation was correlated to the water film thickness (WFT) onto solid particles in UHPC. The rapid increase in static yield stress immediately after mixing (τfloc) showed a linear growth with the decrease of WFT due to enhancement of particle flocculation. A qualitative approach relating particle flocculation and bridging effect of nucleation of early-age hydration products was proposed to describe the rate of linear increase in static yield stress with rest time (Athix). The model yielded good prediction for UHPC prepared with NC, which was not the case for mixtures made with WG where other factors, such as polymer entanglement and association, can play a major role in controlling thixotropy.

Effects of soot volume fraction on local gas heating and particle sizing using laser induced incandescence

Several decades of developing laser induced incandescence (LII) as a combustion diagnostic have led to great advances in understanding soot formation. The bulk of diagnostic development has focused on time-resolved LII (TiRe-LII) where heating of soot particles using a laser, and the subsequent particle cooling, can be measured and matched to a model to determine soot primary particle size. These models vary significantly in both complexity and accuracy. This work focuses on the effect of local gas heating during the soot cooling process. Multi-color pyrometry is performed 5 μs following laser heating on flames ranging in soot volume fraction (SVF) of 10 ppm up to 43 ppm with laser fluences of 0.09 J/cm2, 0.07 J/cm2, and 0.05 J/cm2. Both laser fluence and SVF had significant effects on the local gas heating as measured by the soot temperature. Simulations were performed implementing local gas heating and showed prediction errors depend on pressure and soot volume fraction. As SVF increases, the errors in primary particle size predictions show a nearly linear rate of increase that can become significant at higher SVF values.

TRMM 3B43 Product-Based Spatial and Temporal Anatomy of Precipitation Trends: Global Perspective.

This study harnessed some of the many opportunities provided by the TRMM 3B43 data in order to generate maps illustrating the spatial and temporal distribution of significant linear rates of change of annual total precipitation for the surface of earth bounded by latitudes 50° S and 50° N for the years 1998-2018 by applying pixel-based simple linear regression. These maps are valuable for many applications and should enhance our understanding of the global precipitation patterns and trigger more research in order to explain what has not been explained. It has been found that the whole study area had a mean significant linear rate of change of - 0.4 mm/year. Nearly half of its area had significant linear rates of increase with a mean of 8.5 mm/year while the other half had significant linear rates of decrease with mean of - 7.6 mm/year. Landmass alone can be divided into nearly two halves; the first had significant linear rates of increase with a mean of 5.2 mm/year while the second had significant linear rates of decrease with mean of - 7.0 mm/year. Water areas alone also can nearly be divided into two halves; the first showed significant linear rates of increase with a mean of 9.6 mm/year while the second showed significant linear rates of decrease with mean of - 7.8 mm/year. Grouping the whole study area into six climatic zones and 21 administrative land and water regions and applying pixel-based Tukey test showed that the obtained significant linear rates of change varied significantly among these climatic and administrative regions.

DNA fragmentation of human spermatozoa: Simple assessment of single- and double-strand DNA breaks and their respective dynamic behavioral response.

Procedures to detect sperm DNA fragmentation (SDF), like the sperm chromatin dispersion (SCD) test, determine the "global" SDF without discriminating between spermatozoa with single-strand DNA breaks only (SDF-SSBs) and those containing double-strand DNA breaks (SDF-DSBs). (a) To validate a test to distinguish human spermatozoa with massive DSBs (DSB-SCD assay), (b) to study the baseline SDF-SSBs and SDF-DSBs, and (c) to assess their dynamics in vitro. (a) SDF-DSBs were determined by visualization of diffused DNA fragments from spermatozoa lysed under non-denaturing conditions. This was validated by in vitro incubation with DNase I and the comet assay. (b) Baseline SDF-DSBs and SDF-SSBs were determined in ejaculates from 95 males. (c) Their dynamic appearance was studied in samples untreated or exposed to hyperthermia, acidic pH, nitric oxide released by sodium nitroprusside (SNP), and the metabolic energy inhibitors 2-deoxy-D-glucose and antimycin A. (a) DNase I and comet assay experiments confirmed that the assay successfully determined SDF-DSBs. (b) The higher the SDF of the semen sample, the higher the frequency of SSBs, whereas DSBs behaved independently. Abnormal samples showed higher SDF than normozoospermic, the difference being only significant for SDF-SSBs. (c) During the first hours of incubation, the linear rate of increase in SDF-SSBs was 3.7 X higher than that of SDF-DSBs. All hazardous agents accelerated the SDF rate when compared to untreated spermatozoa, primarily being associated with SDF-SSBs. SNP treatment was the most damaging, rapidly inducing spermatozoa with SSBs which progressively evolved to DSBs. Remarkably, this phenomenon was also evidenced after acute SNP exposure, revealing cryptic sperm damage. The DSBs-SCD is an easy complement for SDF assessment. The dynamic study of SSBs and DSBs may improve the evaluation of sperm quality in clinical settings, particularly "unmasking" the presence of non-specific cryptic sperm damage that might otherwise go undetected.

MODIS-based land surface temperature for climate variability and change research: the tale of a typical semi-arid to arid environment

ABSTRACT This study aims to (1) determine the seasonalities and spatial and temporal rates of change of MODIS-based daytime and nighttime land surface temperature (LST) for the last 19 years from 2000 to 2018 and (2) investigate whether these rates are induced by natural (represented by elevation) or anthropogenic (represented by population counts) forcing. The study area is Jordan – a typical Middle Eastern semi-arid to arid country. Time-series additive seasonal decomposition and simple linear regression produced the following results. (1) For both daytime and nighttime the highest LST values were observed in June while the lowest LST values were observed in December. (2) No significant linear rates of change of LST were noticed in daytime, while significant linear rates of increase of LST, which varied from 0.041°C/year to 0.119°C/year, were observed in nighttime in about one-third of the area of the country mainly in the western parts. (3) The significant linear rates of increase of nighttime LST increased significantly by 0.005°C/year for every 1,000 m increase in elevation and by 0.003°C/year for every 1,000 people increase in population counts. (4) Both natural and anthropogenic factors affected LST in nighttime; however, anthropogenic factors seemed to be more important than natural factors.

Pore structure of reactively synthesized nanolaminate Ti3SiC2 alloyed with Al

Ti3SiC2 has the unique properties integrating the advantages of metals and ceramics, and good open pore structure when alloyed with Al. In this work, porous Ti3SiC2 compounds with different Al/Si atom ratios were prepared through the reactive synthesis of elemental powders at 1300 °C. The results indicate that the phase compositions are determined by Al element mole number, and that the pore structure can be controlled through varying Ti particle size. The MAX phase transits from Ti3SiC2 with Al element mole number no more than 0.6 to Ti3AlC2 with Al element mole number in the range of 0.8–1.2. When Al element mole number is 0.6, the porous compound has a single MAX phase of Ti3SiC2 with uniform microporous structure and high bending strength. Porous Ti3SiC2 alloyed with 0.6Al has a slow linear increase rate of 0.0083%/μm in open porosity with increasing Ti particle size, and a strict linear relationship between the maximum aperture and Ti particle size with the increase rate of 0.0342 μm/μm. The pore structure formed by the phase transition mechanism for porous MAX phase has the smallest tortuosity factor compared with that formed by the clearance mechanism and the Kirkendall effect.

Stability Numbers for a Vertical Circular Excavation with Surcharge

The axisymmetric lower bound finite elements limit analysis technique has been used for computing the stability numbers (γH/c 0) for an unsupported circular vertical excavation in the presence of surcharge pressure (q). The numerical results are presented for various combinations of H/b, ϕ, m and q; the factor m incorporates the rate of linear increase of soil cohesion with depth for a fully cohesive soil medium. The computations reveal that the magnitude of γH/c 0 reduces continuously with (1) increases in the values of q, and (2) decreases in the magnitudes of m, ϕ and H/b.

Photocatalytic degradation of acetic acid in the presence of visible light-active TiO2-reduced graphene oxide photocatalysts

Visible light-active TiO2–reduced graphene oxide photocatalysts were prepared using simple mechanical mixing of titanium dioxide with different amounts of rGO (0.1, 0.5, 1.0 and 2.0wt.%) in the presence of 1-butyl alcohol. Structures and morphologies of the samples were examined by means of FTIR/DRS, UV–vis/DR, XRD, SEM, TEM and Raman spectroscopy. The photocatalytic properties were checked on the basis of acetic acid photooxidation (the steady rate of linear increase of the CO2 yield was used for the estimation of photocatalytic activity). The maximum photodegradation rate was observed for TiO2 decorated with 0.5 wt.% of rGO. The enhancement of photodegradation efficiency should be related to π-conjugation system, two-dimensional planar structure and efficient charge separation of reduced graphene oxide nanosheets.

Improvement of aerosol optical depth retrieval using visibility data in China during the past 50 years

AbstractHorizontal visibility and water vapor pressure data from 483 stations in China from 1960 to 2009 were used to inverse aerosol optical depth (AOD) using a new series of parameters, which were revised for each station using the polybasic nonlinear regression method based on monthly Multiangle Imaging Spectroradiometer (MISR) AOD data during 2001–2005. Monthly AOD retrievals from 2006 to 2009 using the new parameters were compared with MISR AOD in the same period. AOD retrieved with the new parameters can capture the extreme values better than the inversion result with the original parameters, and the root‐mean‐square error between retrieval and MISR AOD reached the minimum of 0.047 in northwest China and the maximum of 0.102 in the Huang–Huai River Basin, respectively. The spatial distribution and seasonal features of monthly AOD from 1960 to 2009 in China were also analyzed. The monthly AOD in China for past 50 years, from 1960 to 2009, exhibited an increasing trend, especially during 1960–1985, with a linear rate of increase of 0.004/year. No distinct trend can be found for AOD from 1985 to 1995; then it increased obviously from 1996 to 2009 with an annual rate of 0.002. Seasonal change in AOD showed that it reached a maximum value in summer with the average value between 0.34 and 0.36 for the whole China, while a minimum value was reached in winter with a mean value between 0.2 and 0.22. It is noted that the aerosol vertical profile was a sensitive factor to the inversion result. The root‐mean‐square error using Goddard Chemistry Aerosol Radiation and Transport aerosol profiles was increased 1.9 to 5.7 times than using the traditional three‐segment profile in northwest, southwest, northeast, and northern China, which meant that the retrieval AOD was sensitive to aerosol vertical profile in these regions; at the same time, the root‐mean‐square error was decreased 1.13 to 1.37 times in other regions.

A comparative study of CO adsorption on tetrahexahedral Pt nanocrystals and interrelated Pt single crystal electrodes by using cyclic voltammetry and in situ FTIR spectroscopy.

This study focuses on CO adsorption at tetrahexahedral Pt nanocrystals (THH Pt NCs) by using cyclic voltammetry and in situ FTIR spectroscopy. Since the electrochemically prepared THH Pt NCs in this study are enclosed by {730} facets which could be considered by a subfacet configuration of 2{210} + {310}, we have also studied CO adsorption on the interrelated Pt(310) and Pt(210) single crystal electrodes as a comparison. Cyclic voltammetry results demonstrated that CO adsorbs dominantly on the (100) sites of THH Pt NCs at low CO coverage (θ(CO)≤ 0.135), while on both (100) and (110) sites at higher CO coverage. On ordered Pt(310) and Pt(210), i.e. they were flame annealed and then cooled in H(2) + Ar, CO adsorption also illustrates relative priority on (100) sites at low CO coverage; while at high CO coverage or on oxygen-disordered Pt(310) and Pt(210) when they were cooled in air after flame annealing, the adsorption of CO presents a weak preference on (100) sites of Pt(310) and even no preference at all on (100) sites of Pt(210). In situ FTIR spectroscopic studies illustrated that CO adsorption on THH Pt NCs yields anomalous infrared effects (AIREs), which are depicted by the Fano-like IR feature on a dense distribution (60 μm(-2)) and the enhancement of abnormal IR absorption on a sparse distribution (22 μm(-2)) of THH Pt NCs on glassy carbon substrate. Systematic investigation of CO coverage dependence of IR features revealed that, on THH Pt NCs, the IR band center (ν(COL)) of linearly bonded CO (COL) is rapidly shifted to higher wavenumbers along with the increase of CO coverage to 0.184, yielding a fast linear increase rate with a high slope (dν(COL)/dθ(IR)(CO) = 219 cm(-1)); when θ > 0.184, the increase of ν(COL) with θCO slows down and deviates drastically from linearity. In contrast, the ν(COL) on the ordered Pt(310) electrode maintains a linear increase with θ(IR)(CO) for the whole range of θ(IR)(CO) variation, and gives a much smaller increase rate of slope 74.3 cm(-1). The significant differences in CO adsorption behavior on THH Pt NCs and on interrelated Pt single crystal planes demonstrated clearly the unique properties of nanoparticles enclosed by high-index facets.

Vertical Uplift Resistance of Two Interfering Horizontal Anchors in Clay

AbstractThe vertical uplift resistance of two interfering rigid strip plate anchors embedded horizontally at the same level in clay has been examined. The lower and upper bound theorems of the limit analysis in combination with finite-elements and linear optimization have been employed to compute the failure load in a bound form. The analysis is meant for an undrained condition and it incorporates the increase of cohesion with depth. For different clear spacing (S) between the anchors, the magnitude of the efficiency factor (ηcγ) resulting from the combined components of soil cohesion (c) and soil unit weight (γ), has been computed for different values of embedment ratio (H/B), the rate of linear increase of cohesion with depth (m) and normalized unit weight (γH/c). The magnitude of ηcγ has been found to reduce continuously with a decrease in the spacing between the anchors, and the uplift resistance becomes minimum for S/B=0. It has been noted that the critical spacing between the anchors required to eli...

Flow structures and their contribution to turbulent dispersion in a randomly packed porous bed based on particle image velocimetry measurements

An experimental study was undertaken to explore the evolution of flow structures and their characteristics within a randomly packed porous bed with particular attention to evaluating turbulent scalar dispersion. A low aspect ratio bed of 4.67 (bed width to spherical solid phase particle diameter) with fluid phase refractive index matched to that of the solid phase was used in order to obtain time resolved two component particle image velocimetry data. Results are based on detailed velocity vector maps obtained at selected pores near the bed center. Pore, or large scale, regions that are associated with the mean flow were identified based on Reynolds decomposed velocity fields, while smaller scale structures embedded within pore scale regions were identified and quantified by combining large eddy scale decomposition and swirling strength analysis. The velocity maps collected in distinctive pore geometries showed presence of three types of flow regions that display very different mean flow conditions, described as regions with tortuous channel like flow, high fluid momentum jet like regions, and low fluid momentum recirculating regions. The major portion of pore space is categorized as tortuous channel flow. Time series of instantaneous velocity field maps were used to identify mean and turbulent flow structures based on their spatial scales in the different regions. Even though regions exhibit varied Eulerian statistics, they show very similar eddy characteristics such as spinning rate and number density. The integral scale eddy structures show nearly a linear rate of increase in their rotation rate with increasing pore Reynolds number, indicating a linear decrease in their time scales. The convective velocities of these eddies are shown to reach an asymptotic limit at high pore Reynolds numbers, unique for each flow region. Detailed Eulerian statistics for the identified flow regions are presented and are used to predict mechanical dispersion through the use of estimated Lagrangian statistics. Contributions from each of the flow regions are presented and the recirculating regions are shown to contribute most to the overall longitudinal dispersion, whereas the tortuous channel regions contribute most to the transverse dispersion. The overall dispersion estimates agree well with global data in the limit of high Schmitt number.

Around the World

In science news around the world this week, North Carolina voted to require that predictions of future sea level rise be based on linear rates of increase, a U.K. panel backed open access to research publications, Australia will create the world's largest network of marine reserves, Bahrain has sentenced 20 medics accused of fomenting revolution, a Senate panel has given NIH a $100 million boost for 2013, and an NRC committee has found that fracking is triggering earthquakes.

Efficient parallel lists intersection and index compression algorithms using graphics processing units

Major web search engines answer thousands of queries per second requesting information about billions of web pages. The data sizes and query loads are growing at an exponential rate. To manage the heavy workload, we consider techniques for utilizing a Graphics Processing Unit (GPU). We investigate new approaches to improve two important operations of search engines -- lists intersection and index compression. For lists intersection, we develop techniques for efficient implementation of the binary search algorithm for parallel computation. We inspect some representative real-world datasets and find that a sufficiently long inverted list has an overall linear rate of increase. Based on this observation, we propose Linear Regression and Hash Segmentation techniques for contracting the search range. For index compression, the traditional d-gap based compression schemata are not well-suited for parallel computation, so we propose a Linear Regression Compression schema which has an inherent parallel structure. We further discuss how to efficiently intersect the compressed lists on a GPU. Our experimental results show significant improvements in the query processing throughput on several datasets.

Further study on the solar activity variation of daytime NmF2

The ionosonde observations in the East Asia‐Australia sector are collected to further investigate the solar activity variation of daytime (0800 ∼ 1600 LT) NmF2. The linear increase rate of NmF2 with F10.7 at lower solar activity levels is remarkably dependent on latitude, season, and local time. The rate is largest in equinoxes (with an equinoctial asymmetry) and higher in the morning (afternoon) in local winter (summer) at geomagnetic midlatitudes; particularly, the maximum rates in local winter are obviously larger than those in local summer at northern midlatitudes. In the equatorial ionization anomaly (EIA) crest regions, the rates in equinoxes and December (June) solstice are remarkably higher than those in June (December) solstice at the northern (southern) EIA crest, and the rate grows from the morning sector to the afternoon sector. The variation trend of NmF2 with F10.7 also shows latitudinal, seasonal, and local time dependences. The saturation effect dominates in all seasons in the EIA regions; at midlatitudes, NmF2 nearly increases linearly with F10.7 in local winter so that a linear fit is a good approximation for NmF2 modeling, while the saturation effect still dominates in other seasons. The saturation effect is more significant in the afternoon, and the strongest saturation effect appears at the EIA crest latitudes in equinox afternoon. Discussions indicate that the variations of neutral atmosphere and hmF2 are responsible for the seasonal and local time dependences of the linear increase rate of NmF2 with F10.7 at midlatitudes, and the seasonal variation of neutral atmosphere is the primary reason for the seasonal dependence of the variation trend of NmF2 with F10.7, while dynamics processes are the more important factors controlling the linear increase rate and the variation trend of NmF2 with F10.7 at low latitudes. Furthermore, dynamics processes are important for the saturation effect, and the fountain effect is related to the strongest saturation effect appearing at the EIA crests.