What is the mechanism of Microwave oven?

Microwave ovens cook with the radiation similar to radar waves. In an ordinary oven, heat first hits the outside of the food and works its way inward. But in microwave oven, radiation goes through the food, bounces off the floor or wall of the oven and goes through the food again. The radiation changes its polarity or its '+'ve and '-'ve direction several billion times a second. The rapidly oscillating microwave radiation acts on the water in food because of a special property of water, ie. water molecule has a '+'ve and '-'ve end - Oxygen and Hydrogen. Every water molecule responds to the reversal of microwave field by reversing itself, twisting back and forth billions of times a second. By the twisting water molecules rub against other molecules, they generate friction, which causes the food to heat up and cook rapidly.

Artificial Blood...

Artificial blood is an emulsion of an oxygen carrying compound, a colloidal substance, plasma expander, electrolytes and a few other buffer compounds. The huge demand for human blood for patient care has led researchers to develop artificial blood. The research (which dates back to the Fifties) is focussed on human recombinant haemoglobin and perfluorocarbons. The artificial haemoglobin rHb 1.1 has oxygen binding characteristics similar to that of HbA in red blood cells. Using recombinant DNA technology rHb 1.1 can be produced in required quantities. Perflurocarbons also dissolve a greater amount of oxygen than RBCs. Its solubility for carbon dioxide is three times that for oxygen. These blood substitutes have different boiling points, molecular structures and gas solubilities. Once they are used up, they form colourless, odourless and stable compounds which can be safely expelled.

Sneeze

Sneezing is a reflux mechanism initiated by irritation on the nasal outer membrane. The irritants stimulate pain fibres in the trigeminal nerve supplying the nasal epitheleum, which transmit afferent nerve fibres the medulla oblongata. Efferent nerve fibres from the medulla oblongata initiate a strong inspiratory effort where in about 2.5 litres of air is inspired. This is followed by strong contraction of the respiratory muscles (including abdominal muscles) building up a high intrapulmonary pressure of about 00 mm Hg. This leads to an explosive outflow of air at velocities reaching upto 965 km/hr.