journal of science education
Classroom
In this section of Resonance, we invite readers to pose questions likely
to be raised in a classroom situation. We may suggest strategies for dealing
with them, or invite responses, or both. “Classroom” is equally
a forum for raising broader issues and sharing personal experiences and
viewpoints on matters related to teaching and learning science.
An Appreciation of Free Radicals
3. Free Radicals in Diseases and Health
In the last 20-25 years, considerable insight has been gained regarding the pivotal role played by free radicals in controlling and directing biological processes that cause diseases, as well as defend against them to maintain health. The manifestation of several hereditary diseases has been traced to the eventual tissue injury/ DNA damage through free radical reactions taking place at various levels in the biological system. A large body of experimental evidence indicates that the chemical trans-formations that induce cancer, stimulate atherosclerosis, lead to Parkinson's and Alzheimer's diseases, cause ischemia, and impel ageing process are basically free radical in nature. Ironically, free radicals are also part of the body's defence mechanism. If genetic predisposition and the life style favour the former, then health becomes the casualty.
Read full article (229 Kb)Part 1. Introduction,
Resonance, Vol.10, No.2, pp.72-78, 2005
Part 2. Free Radical
Reactions in Industry, Resonance, Vol.10, No.3, pp.71-79, 2005
The Mechanical Black Box
A Challenge from the 35th International Physics Olympiad
This article describes an interesting challenge concerning a mechanical black box that was posed as a five hour experimental examination in the 35th International Physics Olympiad held in Pohang, Korea from July 15-23 2004. It marked India's seventh foray into this exciting event where seventy one nations participated. As a leader of the Indian team at Korea, one of us (RBK) was privileged to be in the thick of action. Our performance was a success and we secured one gold, two silver and two bronze medals.
Starting from August 2004, Resonance is publishing in the Classroom section, a series of short articles, ‘Earthquake Tips’, related to earthquakes, their effects on civil structures, and design and construction of earthquake resistant buildings. The concepts are clearly explained with sketches and analogies. We hope the Resonance readers will benefit from this series of articles.
Earthquake Tips have been brought out by the Department of Civil Engineering, IIT Kanpur and sponsored by Building Materials and Technology Promotion Council, New Delhi, India. These articles are reproduced here with permission from IIT Kanpur and BMTPC, New Delhi.
Learning Earthquake Design and Construction
17. How do Earthquakes Affect Reinforced Concrete Buildings?
18. How do Beams in RC Buildings Resist Earthquakes?
Reinforced Concrete Buildings
In recent times, reinforced concrete buildings have become common in India, particularly in towns and cities. Reinforced concrete (or simply RC) consists of two primary materials, namely concrete with reinforcing steel bars. Concrete is made of sand, crushed stone (called aggregates) and cement, all mixed with pre-determined amount of water. Concrete can be molded into any desired shape, and steel bars can be bent into many shapes. Thus, structures of complex shapes are possible with RC.Reinforcement and Seismic Damage
In RC buildings, the vertical and horizontal members (i.e., the beams and columns) are built integrally with each other. Thus, under the action of loads, they act together as a frame transferring forces from one to another. This Tip is meant for beams that are part of a building frame and carry earthquake-induced forces.
.Suggestions/comments may be sent to: eqtips@iitk.ac.in
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