ABSTRACT Distortion is the main problem of welding industry. This problem can be solved by variety of techniques such as heat sinking and side heating. During the heating and cooling cycle thermal strains occurs in the weld and adjacent area. The strains produced during the heating stage of welding are always accompanied by plastic deformation of the metal. The stresses resulting from these strains combine and react to produce internal forces that cause a variety of welding distortions.
The following precautions should be taken in every coal mine for prevention of coal dust explosion: • The suppression of coal dust at the places where it is created by watering down. • Cleaning up the mine and removing any accumulation while ensuring that there is less dis-posal of coal dust into the air • Prevent the ignition sources of coal dust explosion such as methane • All the worked out areas must be sealed off • Application of stone dust which is incombustible in the workplace to prevent combustion from taking place.  Stone dust • The stone dust used must be not cake easily and must be able to disperse into the air. • It must have at least 95 percent of incombustible material and toxic material contained must be less than 5
This liquid refrigerant is forced through a metering or throttling device, also known as an expansion valve (essentially apin-hole sized constriction in the tubing) to an area of much lower pressure. The sudden decrease in pressure results in explosive-like flash evaporation of a portion(typically about half) of the liquid. During evaporation, the liquid vapour refrigerant absorbs its latent heat of vaporization from the product which is to be cooled. This phenomenon known as “auto-refrigeration”. The typically out of the Vapour compression system in shown in above
This kind of Fouling is occurs into the water tubes boilers in which the unburnt fuel or ashes are carried over by the combustion gases that is sucked on the outer surface of the tubes and heavy partials are settle down due to the gravitational forces. Fouling in which the heat exchangers becomes fouled through the process of crystallization. In the tube side the salt water are used as a cold fluid that time the cooling water system are often prone to crystal deposition because of availability of the such as calcium, magnesium carbonate, phosphates and silicates. This materials are damage the inside surface of the tube & decrease the efficiency of the heat exchanger The heat transfer exposed to a corrosive fluid may react, producing corrosion product. Due to the corrosion the fouling will be occur.
While air conditioning systems release the air to cool a space or room with the fan in the unit. Last common difference is in their method of vaporization. Refrigeration units vaporize liquid into gas by means of boiling. It is done in an internal heat exchange coil where the refrigerant has a low pressure that causes the temperature to reach the boiling point. Air conditioning units on the other hand, turn the liquid refrigerant to gas in the evaporator where it evaporates.
In this process plants are either put in water and set over a heat source or placed in a concealed container and steam is introduced through an outside source. It is the steam that extracts the oil from the plant. When the steam rises it is then rapidly cooled to cause condensation. The water/oil mixture is then captured and the oil will separate from the water. The water is syphoned off from the mixture leaving only the essential oil.
The Use of Bomb Calorimeter in Measuring Enthalpies How a bomb calorimeter works? First, put the object that you want to measure inside the bomb. Once everything is plugged in and set up, the electricity passing though the wires, along with the supplied oxygen will combust the object. When is is combusted, heat will be given out. There will be a stir that helps distribute the heat evenly all through the water.
After that it goes in to the economiser where bottom ash is separated out at the bottom part of economiser. After that it will pass through air preheater where air is provide for the coal down the temperature of gas-fly ash mixture and at last it will pass through electrostatic precipitator or bag house where impurities will separated out based on principle of Anion- Cation and rest of the ash is collect at bottom part of the bag house and gases goes in to the stack where gases is liberated directly in to the atmosphere and we get 70-90 % fly ash as a
Heat exchanger is a device which provides a flow of thermal energy between two or more fluids at different temperatures. There are many problems created in the segmental heat exchanger during and after the work. The major causes of this problem is the geometry of heat exchanger, type of fluid used, type of material etc., The purpose of this work is to design the shell and tube heat exchanger which is one among the majority type of liquid –to –liquid heat exchanger. Since the important design parameters such as the pitch ratio, tube length, and tube layer as well as baffle spacing has a direct effect on pressure drop and effectiveness, they are considered to be the key parameters in this work. General design consideration and design procedure
Fire and Explosion Smoking, defective equipment, explosive gas, spark Using fire resistive material, proper ventilation, sprinkles and regular inspection Chemical hazard 3 types of effects: Local—Dermatitis, Eczema, Ulcers, Cancer Inhalation—Gas poisoning Ingestion—Dehydration, Indigestion Sources, effects and preventions Type/ source of chemical contaminant Effect/ organ affected Precautions to be taken Acridines, phenothiazines Dermatitis Cleanliness, removal of people from the areas as soon as first sign of skin reaction is observed. Solvents like chloroform, benzene Unconsciousness Handle with care Vegetable drugs like capsicum & podophyllum Dust evolves, affects eye Goggles are to be worn Improper use of cleaning agents contamination Follow established cleaning procedures Working with radio pharmaceuticals Hazards due to emitted radiation Wearing lead coat, maintaining pressure of working area. Biological Hazard Diseases due to chemical hazards Brucellosis (dairy