GROWTH PERFORMANCES OF CASHEW NUT (Anacamium occidentale L) AND RANAWARA (Accasia auriculata L) UNDER DIFFERENT LEVELS OF SAUNITY

There are large extents of salt affected lands in Sri Lanka, which is estimated to be'223,000 hectares or about 3% of land area of the island, mainly in dry zone areas. Thisseverely affect the productivity of the agricultural lands. And selection of salt-toleranttreelcrop species is considered to be one of the alternatives to overcome this problem.Two separate pot experiments were conducted to study the effect of different salinitylevels on growth performances of cashew nut (Anacardium occidentale L) and Ranawara(Aceasia aurieulata L) at the Faculty of Agriculture, Mapalana. Each tree speciesconsisted of eight treatments, which were differentiated, with different concentrations ofsalinity (i.e. 0, 2, 4, 6, 8, 12, 16, 20mmhos/cm). The experimental design for bothexperiments were Complete Randomized Design (CRD) with 4 replicates. One month oldplants raised in poly bags (10" x-Iz") were used to apply different treatments. 100 ml ofsaline water, which, was prepared by diluting sea water in different treatments wasapplied twice a week. Plant height and the dry matter yield of shoots and roots weremeasured at 3, 6, and 9 weeks after the treatment applicationThe results revealed that plant height, shoot and root biomass has decreased Significantlywith increasing levels of saline water up to 12mmhoslcm compared to the control wherenormal water (O.13mmhoslcm) is applied in cashew nut. Ranawara seems to be more salttolerant. At the early stage, shoot height. shoot weight and root weight significantlydecreased with increasing level of salinity but at latter stage they were not much affectedwith increasing level of salinity. Therefore Ranawara could be recommended as mediumsalt tolerant tree species while cashew nut is not much tolerant to salinity.

Ice Growth from Supercooled Aqueous Solutions of Benzene, Naphthalene, and Phenanthrene

Classical molecular dynamics (MD) were performed to investigate the growth of ice from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene. The main objective of this study is to explore the fate of those aromatic molecules after freezing of the supercooled aqueous solutions, i.e., if these molecules become trapped inside the ice lattice or if they are displaced to the QLL or to the interface with air. Ice growth from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene result in the formation of quasi-liquid layers (QLLs) at the air/ice interface that are thicker than those observed when pure supercooled water freezes. Naphthalene and phenanthrene molecules in the supercooled aqueous solutions are displaced to the air/ice interface during the freezing process at both 270 and 260 K; no incorporation of these aromatics into the ice lattice is observed throughout the freezing process. Similar trends were observed during freezing of supercooled aqueous solutions of benzene at 270 K. In contrast, a fraction of the benzene molecules become trapped inside the ice lattice during the freezing process at 260 K, with the rest of the benzene molecules being displaced to the air/ice interface. These results suggest that the size of the aromatic molecule in the supercooled aqueous solution is an important parameter in determining whether these molecules become trapped inside the ice crystals. Finally, we also report potential of mean force (PMF) calculations aimed at studying the adsorption of gas-phase benzene and phenanthrene on atmospheric air/ice interfaces. Our PMF calculations indicate the presence of deep free energy minima for both benzene and phenanthrene at the air/ice interface, with these molecules adopting a flat orientation at the air/ice interface

Adsorption of Aromatic Hydrocarbon Molecules at the Surface of Ice, As Seen by Grand Canonical Monte Carlo Simulation

The adsorption of four aromatic hydrocarbon compounds, benzene, naphthalene, anthracene, and phenanthrene, at the surface of I-h ice is investigated by grand canonical Monte Carlo (GCMC) computer simulation under tropospheric conditions at 200 K. By systematic variation of the value of adsorbate chemical potential in the simulations, the adsorption isotherms are determined, It is found that adsorption follows the Langmuir mechanism only up to a rather low relative pressure value in every case. In this range specific surface sites, called alpha sites, to which adsorbate molecules can be bound particularly strongly in specific orientation, are occupied. In these alpha sites, presumably the dangling OH bonds of the ice surface form O-H-center dot center dot center dot center dot pi-type hydrogen bonds with the delocalized pi electrons of the adsorbed aromatic molecule lying parallel with the ice surface. Once these alpha sites are saturated, lateral interactions become increasingly important, leading to large fluctuations of the lateral density of the adsorption layer and an increasing deviation of the adsorption isotherm from the Langmuir shape. The adsorption layer is found to be strictly monomolecular and even unsaturated in every case, as condensation well precedes the saturation of this monolayer for all four aromatic adsorbates considered in this study