On numerical evaluation of theH-functions of transport problems by kernel approximation for the albedo 0<ω≤1

Das Gupta represented theH-functions of transport problems for the albedo [0, 1] in the formH(z)=R(z)–S(z) (see Das Gupta, 1977) whereR(z) is a rational function ofz andS(z) is regular on [–1, 0] ^c . In this paper we have representedS(z) through a Fredholm integral equation of the second kind with a symmetric real kernelL(y, z) as . The problem is then solved as an eigenvalue problem. The kernel is converted into a degenerate kernel through finite Taylor's expansion and the integral equation forS(z) takes the form: (which is solved by the usual procedure) where _r 's are the discrete eigenvalues andF _r 's the corresponding eigenfunctions of the real symmetric kernelL(y, z).     

Differential cobalt-induced effects on plant growth,ultrastructural modifications,and antioxidative response among four <Emphasis Type="Italic">Brassica napus</Emphasis> (L.) cultivars

Despite the increasing environmental threat of cobalt in the modern era, less is known as its phytotoxicity behavior. Therefore, the present study was undertaken to assess the toxicity effects of cobalt and to understand the associated physio-biochemical response in Brassica napus, an economically important plant crop species. Five-day-old seedlings of four cultivars (Zheda 619, Zheda 622, ZS 758, and ZY 50) were exposed to five different levels of cobalt under hydroponic conditions. Results showed a concentration-dependent inhibition of plant growth, accompanied by notable chlorophyll loss, protein degradation, and accumulation of reactive oxygen species and malondialdehyde. Further, Co contents in different plants parts were found to be higher in Zheda 622 than all other cultivars. In all cultivars, the contents of enzymatic activities (SOD, POD, GR, and GSH) were markedly increased following cobalt exposure; by contrast, catalase and ascorbate peroxidase activities declined with increased cobalt concentration in medium, which was also, echoed by the pattern of enzymes-related mRNA levels. Morphological observations, supported by ultrastructural analysis revealed clear differences in cobalt sensitivity among cultivars, with ZS 758 identified as less sensitive cultivar, and Zheda 622 the most sensitive one. In addition to revealing genotypic differences in cobalt sensitivity in B. napus, findings suggest the mechanisms of cobalt tolerance in this specie could, at least partially, in relation with the ability of plant to sustain the activity of superoxide dismutase and guaicol peroxidase and to maintain glutathione reduced pool through the action of glutathione reductase.     

Mechanical Effect of Vetiver Grass Root for Stabilization of Natural and Terraced Hill Slope

Geotechnical and Geological Engineering - This paper studies the role of vetiver grass (Vetiveria zizanoides) on the stability of hill slopes through physical and numerical modeling. Vetiver...     

Ready-made garments exports earning and its contribution to economic growth in Bangladesh

GeoJournal - This study attempts to explore the cointegration among economic growth rate, ready-made garments (RMG) exports earning and foreign direct investment (FDI) inflow in Bangladesh. It uses...     

Slope stability analysis of the Rangamati District using geotechnical and geochemical parameters

Natural Hazards - Landslide and human mortality have been a common phenomenon in the Rangamati district over the past several years. This study examined the geotechnical properties (e.g., grain...     

Storm protection service of the Sundarbans mangrove forest,Bangladesh

Natural Hazards - Storm protection service of mangrove is often undervalued. This paper empirically assessed the damage avoided by the Sundarbans mangrove forest in 15 villages of southwest coastal...     

Soil erosion assessment on hillslope of GCE using RUSLE model

A new method for obtaining the C factor (i.e., vegetation cover and management factor) of the RUSLE model is proposed. The method focuses on the derivation of the C factor based on the vegetation density to obtain a more reliable erosion prediction. Soil erosion that occurs on the hillslope along the highway is one of the major problems in Malaysia, which is exposed to a relatively high amount of annual rainfall due to the two different monsoon seasons. As vegetation cover is one of the important factors in the RUSLE model, a new method that accounts for a vegetation density is proposed in this study. A hillslope near the Guthrie Corridor Expressway (GCE), Malaysia, is chosen as an experimental site whereby eight square plots with the size of \(8\times 8\) and \(5\times 5\) m are set up. A vegetation density available on these plots is measured by analyzing the taken image followed by linking the C factor with the measured vegetation density using several established formulas. Finally, erosion prediction is computed based on the RUSLE model in the Geographical Information System (GIS) platform. The C factor obtained by the proposed method is compared with that of the soil erosion guideline Malaysia, thereby predicted erosion is determined by both the C values. Result shows that the C value from the proposed method varies from 0.0162 to 0.125, which is lower compared to the C value from the soil erosion guideline, i.e., 0.8. Meanwhile predicted erosion computed from the proposed C value is between 0.410 and \(3.925\, \hbox {t ha}^{-1 }\,\hbox {yr}^{-1}\) compared to 9.367 to \(34.496\, \hbox {t ha}^{-1}\,\hbox {yr}^{-1 }\) range based on the C value of 0.8. It can be concluded that the proposed method of obtaining a reasonable C value is acceptable as the computed predicted erosion is found to be classified as a very low zone, i.e. less than \(10\, \hbox {t ha}^{-1 }\,\hbox {yr}^{-1}\) whereas the predicted erosion based on the guideline has classified the study area as a low zone of erosion, i.e., between 10 and \(50\, \hbox {t ha}^{-1 }\,\hbox {yr}^{-1}\).     

Approaches for Aggregating Heterogeneous Surface Parameters and Fluxes for Mesoscale and Climate Models

Land surface and climate processes possess dynamics and heterogeneities across a wide range of scales. This study explores the utility of, and procedures for, using local scale measurements to obtain large-scale information. An aggregation scheme is proposed to bridge the scale gap between the scale of measurements including remote sensors and climate and mesoscale models. The proposed scheme derives a set of effective parameters which obeys the energy balance equation exactly and partitions the surface fluxes accurately at different scales. It produces a unique set of aggregated land surface parameters that are easily measurable through remote sensing and have sound mathematical and physical basis. It is shown that aggregated ground heat flux, emissivity and albedo may be obtained by simple areally weighted averaging while temperature, aerodynamic and surface resistances require more involved aggregation operators. The effective surface temperature, although it requires a complicated operator involving subgrid-scale temperature and surface emissivity, is easily measurable through remote sensing. The proposed scheme was compared and contrasted with existing effective parameter approaches. It was shown that several effective parameters of the previous schemes can be easily derived from the proposed scheme by introducing additional assumptions and simplifications.