Preliminary use of water chlorination took place in the mid to late 1800’s. The history of water chlorination for regular disinfection of public water supplies, however, began in the U.S. early in the 20th century and led to a dramatic drop in the incidence of the major waterborne diseases. Impact of Water Chlorination The use…
Environment, the complex of physical, chemical, and biotic factors that act upon an organism or an ecological community and ultimately determine its form and survival. The Earth’s environment is treated in a number of articles. The major components of the physical environment are discussed in the articles atmosphere, climate, continental landform, hydrosphere, and ocean. The relationship between the principal systems and components of the environment,…
Kinematical analysis of a structure can also be done using the static equations. The following criteria for instantaneously changeable systems may be used: (a) Load has finite quantity but the internal forces have infinite values (b) Load is absent and the internal forces are uncertain (type of 0/0) Let us discuss these criteria for structure…
Defects in brickwork EFFECTS OF WORKMANSHIP ON MASONRY STRENGTH Masonry has a very long tradition of building by craftsmen, without engineering supervision of the kind applied to reinforced concrete construction. Consequently, it is frequently regarded with some suspicion as a structural material and carries very much higher safety factors than concrete. There is, of course,…
You can see the results of the work of Elbert Dysart Botts on most modern highways throughout the world. They are the raised reflective pavement markers, or Botts’ dots, that are used as highway markers for warning drivers. Dr. Botts and Botts’ Dots Dr. Elbert Dysart Botts worked with the California Department of Transportation or Caltrans where he oversaw research concerned with road markings…
Important Notation In Engineering Graphics · HP means the Horizontal Plane · VP means the Vertical Plane · FV means the Front View · TV means the Top View · SV means the Side View · STV means the Sectional Top View · GR means the Ground · TL means the True Length · CP means the Cutting Plane · PPP means the Picture Plane…
Establishing control networks and their subsequent computation leads to an implied rectangular coordinate system over the area surveyed. The minor control points in particular can now be used to position topographic data and control the setting out of a construction design. The methods of topographic survey and dimensional control will most probably be: (a) by…
All languages describe “clay”, “sand”, “gravel”, etc., which are terms primarily based on grain size. In the very beginning of the 20th century, Atterberg, a Swedish scientist and agriculturalist, proposed a classification system based on specific grain sizes. With minor modifications, the Atterberg system is still used and are the basis of the International Geotechnical…
Though earthquakes can produce devastating damages to life and property, modern technologies of seismic vibration control such as building elevation control, elevated building foundations, and the use of dampers and springs can assist in minimizing earthquake damage. What Is Seismic Performance Seismic performance is the ability of a structure or a building to maintain its…
Sand is a natural product which is obtained as river sand, nalla sand and pit sand. However sea sand should not be used for the following reasons: 1. It contains salt and hence structure will remain damp. The mortar is affected by efflorescence and blisters appear. 2. It contains shells and other organic matter, which decompose after…