Application of ferrous sulfate alleviates negative impact of cadmium in rice (<i>Oryza sativa</i> L.)

Soil contamination with toxic heavy metals [such as cadmium (Cd)] is becoming a serious global problem due to rapid development of social economy. Iron (Fe), being an important element, has been found effective in enhancing plant tolerance against biotic and abiotic stresses. The present study investigated the extent to which different levels of Ferrous sulphate (FeSO₄) modulated the Cd tolerance of rice (Oryza sativa L.), when maintained in artificially Cd spiked regimes. A pot experiment was conducted under controlled conditions for 146 days, by using natural soil, mixed with different levels of CdCl₂ [0 (no Cd), 0.5 and 1 mg/kg] together with the exogenous application of FeSO₄ at [0 (no Fe), 1.5 and 3 mg/kg] levels to monitor different growth, gaseous exchange characteristics, oxidative stress, antioxidative responses, minerals accumulation, organic acid exudation patterns of O. sativa. Our results depicted that addition of Cd to the soil significantly (P < 0.05) decreased plant growth and biomass, gaseous exchange parameters, mineral uptake by the plants, sugars (soluble, reducing, and non-reducing sugar) and altered the ultrastructure of chloroplasts, plastoglobuli, mitochondria, and many other cellular organelles in Cd-stressed O. sativa compared to those plants which were grown without the addition of Cd in the soil. However, Cd toxicity boosted the production of reactive oxygen species (ROS) by increasing the contents of malondialdehyde (MDA), which is the indication of oxidative stress in O. sativa and was also manifested by hydrogen peroxide (H₂O₂) contents and electrolyte leakage to the membrane bounded organelles. Although, activities of various antioxidative enzymes like superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants like phenolics, flavonoid, ascorbic acid, anthocyanin and proline contents increased up to a Cd level of 0.5 mg/kg in the soil but were significantly diminished at the highest Cd level of 1 mg/kg in the soil compared to those plants which were grown without the addition of Cd in the soil. The negative impacts of Cd injury were reduced by the application of FeSO₄ which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, minerals uptake together with diminished exudation of organic acids as well as oxidative stress indicators in roots and shoots of O. sativa by decreasing Cd retention in different plant parts. These results shed light on the effectiveness of FeSO₄ in improving the growth and upregulation of antioxidant enzyme activities of O. sativa in response to Cd stress. However, further studies at field levels are required to explore the mechanisms of FeSO₄-mediated reduction of the toxicity of not only Cd, but possibly also other heavy metals in plants.     

Heat Transfer Analysis of MHD Power Law Nano Fluid Flow through Annular Sector Duct

Flow and heat transfer analysis of an electrically conducting MHD power law nano fluid is carried out through annular sector duct,under the influence of constant pressure gradient.Two types of nano particles(i.e.Cu and TiO2)are used in power law nano fluid.Strongly implicit procedure,(SIP)is used to simulate the discretized coupled algebraic equations.It has been observed that volume fraction of nano particles,ϕand magnetic field parameter,Ha are favourable for the heat transfer rate,however,both resist the fluid flow.Impact of applied uniform transverse magnetic field exceeds in the case of shear thickening fluids(i.e.n>1)by increasing the value of Ha as compared to that in shear thinning fluids(i.e.n<1).Therefore,enhancement in heat transfer rate is comparably more in shear thickening fluid.Furthermore,comparable limiting case study with published result is also carried out in this research paper.     

A two-dimensional problem of a mode-I crack in a rotating fibre-reinforced isotropic thermoelastic medium under dual-phase-lag model

In the present work, a general model of the equations of generalized thermoelasticity for a homogeneous isotropic elastic half-space solid whose surface is subjected to a mode-I crack problem under the effect of rotation is investigated. The normal mode analyses are used to obtain the expressions for the temperature distribution, the displacement component and thermal stresses in the context of the dual-phase-lag theory of thermoelasticity proposed by Tzou. The boundary of the crack is subjected to a prescribed stress distribution and temperature. Some particular cases are also discussed in the context of the problem. The numerical values of the temperature distribution, the displacement components and thermal stresses are also computed for a suitable material and the results are presented graphically. The effects of rotation, reinforcement and the phase lags parameters are discussed in detail in the light of earlier works.     

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m³), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.     

Autoregressive models in stochastic approximation algorithms for parameter estimation

This paper describes an on-line procedure for estimating the parameters of linear discrete time systems when input and output are subjected to measurement noise of unknown statistics. The algorithm is derived through stochastic approximation, To ensure unbiased parameter estimates, the correlated part of the residuals are first estimated by modelling the residuals as an autoregressive series, and then subtracted from the estimated residuals. The algorithm estimates the system parameters and noise parameters simultaneously. Three gain expressions are derived for the estimation algorithm. They are («) scalar gain, (b) diagonal matrix gain, and (c) square matrix gain.     

Decentralized state estimation in large-scale systems

A novel approach to decentralized state estimation in a large-scale interconnected system is proposed. The method assumes a known model for the local subsystem only, and therefore is suitable when the other subsystem models and the interaction matrices are partially or totally unknown. An innovation representation suitable for decentralized subsystem state estimation is derived. The state estimation problem is then solved through the parametric identification of the innovation representation. The identification algorithm is based upon a pseudo-linear regression (PLR) principle that attempts minimization of the innovation variances.     

Technical Note Photointerpretation of Pleistocene Mediterranean ridges south-west of Alexandria

Abstract

The Pleistocene ridges south-west of Alexandria are of marine origin and represent the ancient shoreline of the former sea levels. Several authors have described the nature, origin and geomorphology of the Pleistocene ridges. The objective is to delineate these ridges using aerial photomosaics at 1:100000 scale and a Landsat image at 1:250000 scale.

The area is covered by beach sands in the northern part and consolidated limestone forming coastal ridges southwards. The lowlands between the ridges are occupied by marshes, lagoons or mixtures of clay and lime materials. Plant cover occurs in the central part. The different ridges recognized photogeologically are eight ridges and the foreshore ridges are more distinct than those of the backshore. Owing to the presence of plant cover, some ridges appear as faint lines. The ridges and lowlands appear on photomosaics with tonal contrast where successive light and dark toned areas can be easily identified. The interpreted ridges were correlated with those in the topographic map with the same scale and covering the same area. It was found that a number of these ridges follow the configuration of the relief where they are represented by high peaks. Ridges appear as elongated alignments nearly parallel with the Mediterranean Sea shore with a general trend NE-SW. The presence of some minerals such as augite and the size of their grains indicate that the sea currents and prevailing wind directions were coming mainly from the east or north-east whereas the reverse case occurs nowadays. Photointerpretation indicated the presence of a number of fractures trending NW-SE, dissecting the ridges in the northern part of the area.     

Trajectory estimation of manoeuvring re-entry vehicles and non-linear filtering

This paper presents a modified Sridhar filter which is applied to the problem of the real-time estimation of the trajectory of a manoeuvring re-entry vehicle (MARV) from its radar observations. The Sridhar filter is based on optimal control concepts, specifically the Pontryagin minimum principle and the method of invariant imbedding. In this approach the unknown forces on the MARV are treated as controls that drive the MARV dynamics to track the noisy observed trajectory. This treatment differs from that used with the extended Kalman filter (EKF), where a new state vector of the unknown forces acting on the MARV considered as Wiener processes is augmented to the MARV state vector. The Sridhar filter does not increase the MARV state vector so its computational time, for the cases studied, is about 20% that of the EKF. The performance, as measured by the point error, of the proposed approach is even better than that of the conventional EKF.     

On a case of dynamic feedback optimization†

In this paper the problem of selecting an optimal feedback controller, from a class of linear systems, for a non-linear dynamical system, is reduced to a standard parameter optimization problem given by Boltyanskii. A necessary condition for the selection of the optimal parameters is presented.