An application of principal component analysis for pre- harvest forecast model for rice crop based on biometrical characters

An application of principal component analysis for the development of suitable statistical models for preharvest forecast of rice yield based on biometrical characters has been dealt with in the present paper. The data obtained from the two experiments on rice have been utilised to develop the model. The forecast yields of based onthese models have been found to be 24.25, 22.60 and 21.10 q/ha against the actual yield of 28.00, 23.56 and 21.85 q/ha, respectively, in experiment –I. For experiment –II the forecast yields were found to be 24.62, 28.06 and 29.43 q/ha against the actual yield of 28.82, 29.31 and 26.59 q/ha, respectively. These forecast yields are subject to maximum of almost 10 percent standard error. In most of the cases, the forecast yields were found to be close to the actual yield except in some cases. The values of R2, i.e. 79.80 and 72.60 for experiment –I and II, respectively, indicate the validity of the models. Statistical tool like viz. principal component analysis (PCA) has been first time applied to develop pre-harvest forecast model based on experimental data

Dynamical complexities in a tri-trophic hybrid food chain model with Holling type II and Crowley–Martin functional responses

We study how predator behavior influences community dynamics of predatorprey systems. It turns out that predator behavior plays a dominant role in community dynamics. The hybrid model studied in this paper reveals that period-doubling and period-doubling reversals can generate short-term recurrent chaos (STRC), which mimics chaotic dynamics observed in natural populations. STRC manifests itself when deterministic changes in a system parameter interrupt chaotic behavior at unpredictable intervals. Numerical results reinforce an earlier suggestion that period-doubling reversals could control chaotic dynamics in ecological models. In ecological terms, the prey and intermediate predator populations may go to extinction in the event of a catastrophe. The top predator is always a survivor. In contrast to this, this is not the case when the constituent populations are interacting through Holling type II functional response. Even this top predator can go to extinction in the event of such catastrophes

Removal of hexavalent chromium Cr (VI) using activated carbon prepared from mango kernel activated with H3PO4

The present work reported the adsorption of Cr (VI) from aqueous solutions on activated carbon prepared from mango kernel, a seasonal waste from mango fruits. Kernels from dried mango fruit shells were taken out and pulverized in a micro-pulverizing mill. The powder thus obtained was activated with 40% H3PO4 and carbonized at 600 °C for 1 hour in an inert atmosphere. Physico-chemical characteristics such as elemental composition, surface area, functional groups and surface morphology of the activated carbon were analyzed using elemental analyzer, BET surface area analyzer, FTIR spectroscopy and SEM analysis respectively. Batch adsorption experiments were performed to investigate the effects of Cr (VI) concentration, carbon dose, pH, rate of agitation, time and temperature. The maximum adsorption capacity of Cr(VI) was found to be 7.8 mg g−1 at pH 2 and temperature 35 °C. The Langmuir adsorption isotherm best represented the equilibrium data and a pseudo-second order relation represented the adsorption kinetics