THEORETICAL ANALYSIS OF A WET COOLING TOWER FOR FRESH WATER FROM PLUME AND ANALYZING AN INDUSTRIAL COOLING TOWER BASED ON RESULTS

A cooling tower is a heat rejection device which rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. The stream of saturated exhaust air leaving the cooling tower called the plume is visible when water vapor it contains condenses in contact with cooler ambient air, like the saturated air in one's breath fogs on a cold day. Under certain conditions, the cooling tower plume may present fogging or icing hazards to its surroundings and gives some environmental problems. To find the solution for this problem a cooling tower has been analysed based on air flow rate through the tower and the cooling load to obtain fresh water yield by utilising plume from cooling tower top. The theoretical analysis gives the values of important parameters Theoretical analysis has been done on wet cooling tower by varying the water flow rate through which affect the performance of a cooling tower such as the cooling range, effectiveness, approach, fresh water yield etc. Then with the conditions of a trials from the analysis, the mass flow rate of water in the cooling tower was scaled up to match the mass flow rate of water in an industrial cooling tower. This helps in obtaining the mass flow rate of the air and fresh water yield through the industrial cooling tower

Application of Value Stream Mapping for Reduction of Cycle Time in a Machining Process

AbstractLean manufacturing initiative is being followed by various organizations in the recent years which mainly focuses on improving the efficiency of operations by eliminating and reducing wastes. This paper aimed to explain the implementation of lean manufacturing techniques in the crankshaft manufacturing system at an automotive manufacturing plant located in south India.. A multi criteria decision making model, analytical hierarchy process is applied to analyze the decision making process in the manufacturing system. The objective of the case industry was to increase the export sales. Lean manufacturing system was selected to meet the company“s quality, cost and delivery targets. Crankshaft was manufactured in a single piece flow system with the low cost machines developed indigenously and the results are that the crankshafts have passed the testing, validation and approval by the customer to produce any variant in the company. After implementing lean manufacturing system, the manufacturing lead time reduced by forty percent, defects were reduced, higher process capability achieved, quick response to the customer demand in small lots were achieved

Effect of alkali metal doping on the properties and crystalline perfection of bis(thiourea)zinc(II) chloride crystals

The influence of sodium doping on the properties of bis(thiourea)zinc(II) chloride crystals has been described. The reduction in the intensity observed in powder X-ray diffraction of doped specimen and slight shifts in vibrational frequencies confirm the lattice stress as a result of doping. The incorporation of Na(I) into the crystal lattice was confirmed by energy dispersive X-ray spectroscopy. Surface morphological changes due to doping of the alkali metal are observed by scanning electron microscopy. The TG-DTA studies reveal the purity of the material and no decomposition is observed up to the melting point. The high resolution X-ray diffraction studies reveal that the crystalline quality is improved considerably by doping with alkali metal. High transmittance is observed and cut off lambda is similar to 270 nm

The molecular envelope around the red supergiant VY CMa

We present millimeter interferometric observations of the molecular envelope around the red supergiant VY CMa with the Submillimeter Array (SMA). The high angular resolution (<2′) allows us to derive the structure of the envelope as observed in the 1.3 mm continuum, 12CO(2-1), 13CO(2-1), and SO(6 5-5 4) lines emission. The circumstellar envelope is resolved into three components: (1) a dense, compact, and dusty central component, embedded in (2) a more diffuse and extended envelope, and (3) a high-velocity component. We construct a simple model, consisting of a spherically symmetric slowly expanding envelope and bipolar outflows with a wide opening angle (∼120°) viewed close to the line of sight (i = 15°). Our model can explain the main features of die SMA data and previous single-dish CO multiline observations. An episode of enhanced mass loss along the bipolar direction is inferred from our modeling. The SMA data provide a better understanding of the complicated morphology seen in the optical/IR high-resolution observations. © 2007. The American Astronomical Society. All rights reserved.published_or_final_versio

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Probing the mass loss history of the yellow hypergiant IRC+10420

We have used the sub-millimeter array to image the molecular envelope around IRC+10420. Our observations reveal a large and clumpy expanding envelope around the star. The molecular envelope shows a clear asymmetry in $^{12}$CO J=2--1 emission in the South-West direction. The elongation of the envelope is found even more pronounced in the emission of $^{13}$CO J=2--1 and SO J$_{\rm K}$=6$_5$--5$_4$. A small positional velocity gradient across velocity channels is seen in these lines, suggesting the presence of a weak bipolar outflow in the envelope of IRC+10420. In the higher resolution $^{12}$CO J=2--1 map, we find that the envelope has two components: (1) an inner shell (shell I) located between radius of about 1"-2"; (2) an outer shell (shell II) located between 3" to 6" in radius. These shells represent two previous mass-loss episodes from IRC+10420. We attempt to derive in self-consistent manner the physical conditions inside the envelope by modelling the dust properties, and the heating and cooling of molecular gas. We estimate a mass loss rate of $\sim$9 10$^{-4}$ M$_\odot$ yr$^{-1}$ for shell I and 7 10$^{-4}$ M$_\odot$ yr$^{-1}$ for shell II. The gas temperature is found to be unusually high in IRC+10420 in comparison with other oxygen-rich envelopes. The elevated gas temperature is mainly due to higher heating rate, which results from the large luminosity of the central s tar. We also derive an isotopic ratio $^{12}$C/$^{13}$C = 6.Comment: 30 pages, 14 figures. Accepted for publication in The Astrophysical Journa