Alternate energy resources

Automobiles use fossil fuels extensively. Fossil fuel production may reach in its peak in the year 2015. Thereafter fossil fuel production will decline gradually. A maximum of 100 more years, fossil fuels can serve as an energy source for human kind. After that, only alternate energy sources will help. So a serious study in the field of alternate energy sources is required. Water power is an option. Hydroelectric power plants use water stored in reservoirs and tidal plants use ocean tides.  But these options may harm environment badly. Nuclear power is another option. Nuclear power is obtained from nuclear fission reactions. Uraniun-235 isotope is used here. But safety concern is a big issue in nuclear power plant.  The solar energy is another option. It is environment friendly and readily available anywhere in the world. Wind power is an option but equipments are very much expensive. Geothermal energy is an option where energy is extracted from the molten interior of the earth.

Colloidal electrolytes

Electrolytes are widely used for metal plating, in battery and for accelerating certain chemical reactions. A simple electrolyte can be prepared by mixing sodium and potassium salts of long-chain fatty acids in alcoholic solution. Aqueous solutions of soap are known as colloidal electrolytes which show higher boiling point and smaller colligative properties. Their electrical conducting properties are superlative. Here aqueous solutions of the soaps are ionized into an alkali metal cation and a fatty acid anion. An increase in the soap concentration results in grouping of anions to form ionic micelles. These ionic micelles contain ten or more ions with some water molecules associated with them. Highly viscous soap solutions yields extensively hydrated particles. Ionic micelles contribute less towards colligative properties. The main contributor is alkali metal ion. Heavy concentrations of soap results in large crystalline particles which have a laminated structure. Such a system is known as lamellar colloids which have conductivity properties similar to that of a normal colloidal system.

Airfoils

Aeronautics is now a branch of technology which offers tremendous potential for growth. Aero plane structure, shape and operation are very important for an aeronautical engineer. Airfoils are the cross sectional shapes of wings. General definition is that air foils are intersections with planes parallel to the free stream and normal to the plane of the wing. In a swept-back wings system, airfoils are defined in a plane perpendicular to the quarter chord line. Some concepts of fluid mechanics are required for the better understanding of essential characteristics of airfoils. Rounded leading edge is a must for air foils with the radius of curvature sufficiently large. This avoids excessive suction. Trailing edge of airfoils must be sharp. This is to establish Kutta- Joukowski condition. Wings should be made thicker (which makes a better structural beam). This allows load carriage with less structural weight. Six series airfoils were used in early jet engines. Then came peaky airfoils. Later NASA developed a high speed airfoil, supercritical airfoil with very small curvature over much of the upper surface so that the aft-facing surface has very little vertical projected area for a considerable distance behind the crest.