Application of a system dynamics approach for assessment and mitigation of CO2 emissions from the cement industry

A system dynamics model based on the dynamic interactions among a number of system components is developed to estimate CO(2) emissions from the cement industry in India. The CO(2) emissions are projected to reach 396.89 million tonnes by the year 2020 if the existing cement making technological options are followed. Policy options of population growth stabilisation, energy conservation and structural management in cement manufacturing processes are incorporated for developing the CO(2) mitigation scenarios. A 42% reduction in the CO(2) emissions can be achieved in the year 2020 based on an integrated mitigation scenario. Indirect CO(2) emissions from the transport of raw materials to the cement plants and finished product to market are also estimated.     

Phototransformation of chlorimuron-ethyl on leaf surface

Chlorimuron-ethyl, a post-emergent herbicide selectively used in soybean and maize, degrades mainly through chemical hydrolysis. Photolysis has also an important role in the degradation of this compound. Phototransformation of chlorimuron-ethyl takes place through the cleavage of the sulfonylurea bridge, dechlorination, de-esterification and cyclization. Enzymatic de-esterification usually takes place in plant system to liberate the free acid, chlorimuron, which, in fact, inhibits the acetolactate synthase enzyme. In the non-enzymatic environment, de-esterification generally does not occur at normal pH and in moisture-free medium. But on the leaf surface of maize crop de-esterification of chlorimuron-ethyl takes place. The moisture deposited on leaf surfaces by virtue of evapo-transpirational loss of water may cause the de-esterification of chlorimuron-ethyl to the free acid, chlorimuron.     

Phototransformation of quinalphos on clay surfaces

Photochemical decomposition of quinalphos was studied on clay surfaces (kaolinite, paly‐gorskite). Photoproducts were characterized by comparison with the authentic samples and GC‐MS. Rate of degradation on both the clays followed first order kinetics with significant correlation coefficient.     

Effect of surfactants on persistence of azadirachtin-A (neem based pesticide)

Photostability of azadirachtin-A, a neem based pesticide, was studied in the presence of non-ionic surfactants. Surfactants such as Span-80, Atlox 3400B, Tween-80, Agrimul 52B, and Agrimul N4S enhanced the rate of photodegradation of azadirachtin-A, whereas surfactants such as Triton-X, Emulsol CFA, Tween-20, Emulsol MAS, and Emulsol-N-33 decreased the rate of degradation. Emulsol-N-33 was found to be the most effective surfactant, as half life of azadirachin-A in the presence of Emulsol-N-33 was found to be 94.93 min in comparison to 48 min for azadirachtin-A alone under UV light.     

Investigations of methane emissions from rice cultivation in Indian context

The increasing demand of the growing population requires enhancement in the production of rice. This has a direct bearing on the global environment since the rice cultivation is one of the major contributors to the methane emissions. As the rice cultivation is intensified with the current practices and technologies, the methane fluxes from paddy fields will substantially rise. Improved high yielding rice varieties together with efficient cultivation techniques will certainly contribute to the curtailment of the methane emission fluxes. In this paper, the system dynamic approach is used for estimating the methane emissions from rice fields in India till the year 2020. Mitigation options studied for curtailing the methane emissions include rice production management, use of low methane emitting varieties of rice, water management and fertilizer amendment. The model is validated quantitatively and sensitivity tests are carried out to examine the robustness of the model.