Hall and ion-slip effects on the unsteady MHD mixed convection of Cu-water nanofluid over a vertical stretching plate with convective heat flux

The problem of unsteady MHD mixed convective flow of a Cu-water nanofluid over a vertical convectively heated plate has been analyzed. The effects of Hall and ion-slip currents have also been taken into consideration. The governing nonlinear partial differential equations have been reduced to a system of nonlinear coupled similarity equations. The resulting similarity equations have been solved numerically to obtain the axial velocity, transverse velocity and temperature in the corresponding boundary layers. It has been found that the variations of the Hall and ion-slip parameters can remarkably affect the velocity and temperature distributions of the nanofluid. Further, the transfer characteristics of the axial velocity, the transverse velocity and the temperature of Cu-water nanofluid under various values of unsteadiness parameter, magnetic parameter, the boundary convection parameter and the mixed convection parameter have been described and discussed, respectively

Multiple male and female reproductive strategies and the presence of a polyandric mating system in the termite Reticulitermes labralis (Isoptera:Rhinotermitidae)

Reproductive systems of termite colonies may involve the number of individuals in the reproductive caste and the copulatory selectivity of reproductive individuals (i.e., polyandry or polygamy), both of which directly impact the fertility and genetic diversity of the colony. Polygamy is widespread in the lower termites, whereas polyandry appears to be mostly absent in termites. In this paper, the differentiation of male and female neotenics were observed in orphaned experimental colonies of the subterranean termite Reticulitermes labralis. The artificial orphaned colonies began to produce neotenics a week after colony establishing, with more neotenics appearing in the same group over time. Finally, each experimental group reserved multi-neotenics that consisted of male and female neotenic individuals. Our results demonstrated that these neotenic individuals retained in the colony participated in reproduction. A genetic analysis at four microsatellite loci showed that in addition to the conspicuous morphologically male reproductives, there were inconspicuous males or workers that had copulated with the females in the orphaned colony. Multiple male and female reproductive individuals existed together in a single colony, and one female neotenic could mate with several male reproductives in a short time. Thus, multiple male and female reproductive systems and a polyandric mating system are present in R. labralis

Automatic Recognition of Seismic Intensity Based on RS and GIS: A Case Study in Wenchuan Ms8.0 Earthquake of China

In recent years, earthquakes have frequently occurred all over the world, which caused huge casualties and economic losses. It is very necessary and urgent to obtain the seismic intensity map timely so as to master the distribution of the disaster and provide supports for quick earthquake relief. Compared with traditional methods of drawing seismic intensity map, which require many investigations in the field of earthquake area or are too dependent on the empirical formulas, spatial information technologies such as Remote Sensing (RS) and Geographical Information System (GIS) can provide fast and economical way to automatically recognize the seismic intensity. With the integrated application of RS and GIS, this paper proposes a RS/GIS-based approach for automatic recognition of seismic intensity, in which RS is used to retrieve and extract the information on damages caused by earthquake, and GIS is applied to manage and display the data of seismic intensity. The case study in Wenchuan Ms8.0 earthquake in China shows that the information on seismic intensity can be automatically extracted from remotely sensed images as quickly as possible after earthquake occurrence, and the Digital Intensity Model (DIM) can be used to visually query and display the distribution of seismic intensity

Dust aerosol impact on North Africa climate: a GCM investigation of aerosol-cloud-radiation interactions using A-Train satellite data

The climatic effects of dust aerosols in North Africa have been investigated using the atmospheric general circulation model (AGCM) developed at the University of California, Los Angeles (UCLA). The model includes an efficient and physically based radiation parameterization scheme developed specifically for application to clouds and aerosols. Parameterization of the effective ice particle size in association with the aerosol first indirect effect based on ice cloud and aerosol data retrieved from A-Train satellite observations have been employed in climate model simulations. Offline simulations reveal that the direct solar, IR, and net forcings by dust aerosols at the top of the atmosphere (TOA) generally increase with increasing aerosol optical depth. When the dust semi-direct effect is included with the presence of ice clouds, positive IR radiative forcing is enhanced since ice clouds trap substantial IR radiation, while the positive solar forcing with dust aerosols alone has been changed to negative values due to the strong reflection of solar radiation by clouds, indicating that cloud forcing associated with aerosol semi-direct effect could exceed direct aerosol forcing. With the aerosol first indirect effect, the net cloud forcing is generally reduced in the case for an ice water path (IWP) larger than 20 g m<sup>−2</sup>. The magnitude of the reduction increases with IWP. <br><br> AGCM simulations show that the reduced ice crystal mean effective size due to the aerosol first indirect effect results in less OLR and net solar flux at TOA over the cloudy area of the North Africa region because ice clouds with smaller size trap more IR radiation and reflect more solar radiation. The precipitation in the same area, however, increases due to the aerosol indirect effect on ice clouds, corresponding to the enhanced convection as indicated by reduced OLR. Adding the aerosol direct effect into the model simulation reduces the precipitation in the normal rainfall band over North Africa, where precipitation is shifted to the south and the northeast produced by the absorption of sunlight and the subsequent heating of the air column by dust particles. As a result, rainfall is drawn further inland to the northeast. This study represents the first attempt to quantify the climate impact of the aerosol indirect effect using a GCM in connection with A-Train satellite data. The parameterization for the aerosol first indirect effect developed in this study can be readily employed for application to other GCMs

Enhanced Heavy Oil Recovery in Mild Conditions by S

The important key of heavy oil efficient exploring is to decrease the viscosity and increase the flowability. Solid acid catalyst is one of the commonly used catalysts to reducing the viscosity of heavy oil, but good dispersion in oil phase and better catalytic activity are difficult to achieve. Herein, ZrO2-TiO2 was selected as the fundamental catalyst because of its superior solid superacid properties, and CTAB was selected as the surfactant package coat to help enhance catalytic activity. The as-prepared catalysts were characterized systematically by TEM, XRD, FTIR, and N2 adsorption-desorption isotherms measurement. The reduction efficiency of the heavy oil viscosity achieved as high as 66.3% at 180°C. At the same time, the portion of asphaltenes and resins slipped down by 4.93% and 3.78%, respectively, while saturated and aromatic hydrocarbon component increased by 5.37% and 3.26%, respectively, indicating that our catalyst showed a good activity for reducing the viscosity and improving the quality of heavy crude oil

Dynamically Relative Position Encoding-Based Transformer for Automatic Code Edit

Adapting Deep Learning (DL) techniques to automate non-trivial coding activities, such as code documentation and defect detection, has been intensively studied recently. Learning to predict code changes is one of the popular and essential investigations. Prior studies have shown that DL techniques such as Neural Machine Translation (NMT) can benefit meaningful code changes, including bug fixing and code refactoring. However, NMT models may encounter bottleneck when modeling long sequences, thus are limited in accurately predicting code changes. In this work, we design a Transformer-based approach, considering that Transformer has proven effective in capturing long-term dependencies. Specifically, we propose a novel model named DTrans. For better incorporating the local structure of code, i.e., statement-level information in this paper, DTrans is designed with dynamically relative position encoding in the multi-head attention of Transformer. Experiments on benchmark datasets demonstrate that DTrans can more accurately generate patches than the state-of-the-art methods, increasing the performance by at least 5.45\%-46.57\% in terms of the exact match metric on different datasets. Moreover, DTrans can locate the lines to change with 1.75\%-24.21\% higher accuracy than the existing methods

Type-Dependent Responses of Ice Cloud Properties to Aerosols From Satellite Retrievals

Aerosol‐cloud interactions represent one of the largest uncertainties in external forcings on our climate system. Compared with liquid clouds, the observational evidence for the aerosol impact on ice clouds is much more limited and shows conflicting results, partly because the distinct features of different ice cloud and aerosol types were seldom considered. Using 9‐year satellite retrievals, we find that, for convection‐generated (anvil) ice clouds, cloud optical thickness, cloud thickness, and cloud fraction increase with small‐to‐moderate aerosol loadings (<0.3 aerosol optical depth) and decrease with further aerosol increase. For in situ formed ice clouds, however, these cloud properties increase monotonically and more sharply with aerosol loadings. An increase in loading of smoke aerosols generally reduces cloud optical thickness of convection‐generated ice clouds, while the reverse is true for dust and anthropogenic pollution aerosols. These relationships between different cloud/aerosol types provide valuable constraints on the modeling assessment of aerosol‐ice cloud radiative forcing

Forest Evapotranspiration and Energy Flux Partitioning Based on Eddy Covariance Methods in an Arid Desert Region of Northwest China

In this study, the characteristics of energy flux partitioning and evapotranspiration of P. euphratica forests were examined in the extreme arid region of Northwest China. Energy balance closure of the ecosystem was approximately 72% (H + LE = 0.72 ∗ (Rn-G)+7.72, r2=0.79, n=12095), where Rn is the net radiation, G is the soil heat flux, H is the sensible heat flux, and LE is the latent heat flux. LE was the main term of energy consumption at annual time scale because of higher value in the growing season. The ratios of the latent (LE) and sensible (H) heat fluxes to net radiation were 0.47 and 0.28 throughout the year, respectively. Moreover, the yearly evapotranspiration of P. euphratica forests was 744 mm year−1. And the mean daily ET was 5.09 mm·d−1 in the vibrant growing season. In particular, a small spike in the actual evapotranspiration distribution occurred during the soil ablation period due to the higher temperature and sufficient soil moisture associated with soil thawing. This period is accompanied by a series of physical processes, such as moisture transfer and heat exchange

Carbon dioxide fluxes and their environmental controls in a riparian forest within the hyper-arid region of Northwest China

Hyper-arid regions are expected to undergo climatic change, but only a few research works have so far been conducted on the dynamics of carbon dioxide (CO2) fluxes and their consequent responses to various bioclimatic factors, which is mainly attributable to a limited set of flux observations. In this study, the CO2 fluxes exchanged between the forest and the atmosphere have been measured continuously by the eddy covariance approach from June 2013 to December 2016 in a riparian forest, which is a primary body of natural oases located within the lower reaches of inland rivers in China. The present results revealed that the climatic conditionscharacterized by relatively high mean air temperatures (Ta) with fluctuating annual precipitation (P) during the prescribed study periods were comparable to the historical mean value. The annual net ecosystem productivity (NEP) ranged from approximately 278 g C m−2 year−1 to 427 g C m−2 year−1, with a mean value of 334 g C m−2 year−1. The mean annual ecosystem respiration (Re) and the gross primary productivity (GPP) were found to be 558 and 892 g C m−2 year−1, respectively. The results also ascertained that the high inter-annual variations in NEP were attributable to Re rather than to GPP, and this result was driven primarily by Ta and the groundwater depth under similar eco-physiological processes. In addition, the CO2 fluxes were also strongly correlated with the soil temperature and photosynthetically active radiation for the present study site. In conclusion, the desert riparian forest is a considerably significant carbon sink, particularly in the hyper-arid regions