A frequency domain based dynamic simulation package for continuous distillation units

A digital simulation package for dynamic simulation of continuous distillation units in the frequency domain is presented. The package is based on a rigorous dynamic model that can account for all dynamic phenomena known to be important for control studies. Two industrial scale problems ar presented to demonstrate the software: a fictitious but representative 64-tray deisobutanizer, and an actual 91-tray ethane-ethylene splitter. Simulation results reveal the power of the package in computing a wide variety of frequency responses with sufficient accuracy.© IEE

Carbonate Lumps in the Lawson's Bay Area, Visakhapatnam, East Coast of India

72-74Modern carbonate lumps are found in the Lawson's Bay area. The carbonate lumps are inferred to have been deposited by biochemical process in the littoral zone. Abundant high Mg-calcite with subordinate aragonite and dolomite are the minerals in the carbonates. Aragonite and dolomite are considered to have been formed by the diagenetic alteration of high Mg-calcite. Amphiroa fragilissima and Chaetomorpha sp. are the dominant algal forms present in the carbonates. No direct evidence on the age of carbonates in the bay could be obtained

Sedimentation And Sea-Level Variations In Nizampatnam Bay, East-Coast Of India

261-264Nizampatnam bay is a shallow marine environment just south of the Krishna delta on the east coast of India. Holocene transgression and subsequent progradation of the Krishna delta played a major role in the evolution of the bay. Though there is wide range in the sediment types, the bay is predominantly occupied by sandy clays and sands. Coarse sandy sediments (Mz 0.96-1.4-φ), which are better sorted and negatively skewed, are mostly confined to offshore bar. Poorly sorted and positively skewed sandy clays cover the central and some nearshore areas of the bay. Coarse sand in the offshore bar and geometry of the sand body indicate a rapid rise in the sea level and overstepping of the bar. 14C dating gives an age of about 8000 y BP for the ancient strandline located at about 25 km from the present coastline. Following the sea level rise, the bar blocked off the sediments supplied by the river and led to the deposition of fine sediments throughout the bay. Widespread occurrence of sandy clay and poor sorting of the sediments give testimony to the low energy conditions in the bay caused by the offshore bar. Sand bodies in the coastal region particularly in the northwestern part of the bay are considered to be due to wave induced longshore drift of the sediments to the south. Continuous infilling of the bay is indicated by decrease in the depths during the last century

Benthic Foraminifera from Littoral Sediments of Al Lith-Al Qunfidhah Coast, Southeastern Red Sea

217-221Fifty five surface sediment samples from the nearshore area between Al Lith and Al Qunfidhah, southeastern Red Sea have been analysed for benthic Foraminifera. In contrast with the northeastern parts of the Red Sea, rotaliids dominate the fauna of this region. However, in sediments rich in carbonate, miliolids are abundant. Textularids are very rare. Rotaliids are mostly associated with fine sediments, while miliolids are shared between coarse and fine sediments. The relative dominance of Rotaliina over Miliolina is attributed to the periodic influx of fresh water and mixing of terrigenous sediments with the in situ carbonates. The observed dominance of Miliolina over Rotaliina in certain sediments along the coast indicates typical character of subtropical carbonates and no hypersaline conditions in those places