Patents by Inventor Narayanrao Ramakrishnan

Narayanrao Ramakrishnan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7524452
    Abstract: A low temperature process for making radiopac materials is disclosed. The process utilizes industrial/agricultural waste as raw materials and includes mixing 11-88% w/w of the industrial/agricultural waste materials, 11-88% w/w of an alkali or alkaline earth metal compound and 7-15% w/w of a phosphatic binder to obtain a homogenized mixture. The homogenized mixture is compressed at a pressure in the range of 100-300 Kg/cm2 to obtain compacted green material samples. The compacted green material samples are baked for 1-3 hours in an Air oven in the temperature range of 90-130° C., and are sintered at a temperature in the range of 920 to 1300° C. for a soaking period of 1-3 hours under air environment in a muffle furnace to obtain the radiopac material.
    Type: Grant
    Filed: January 3, 2005
    Date of Patent: April 28, 2009
    Assignee: Council of Scientific and Industrial Research
    Inventors: Sudhir Sitaram Amritphale, Navin Chandra, Narayanrao Ramakrishnan
  • Publication number: 20060066013
    Abstract: A novel process is for making ceramic based radiopac materials useful for X-ray radiation attenuation. The process is lead as well as rare earth free and thus obviates (i) the use of conventionally used lead metal and its compounds—which are toxic in nature and are heavy weight as the density of lead is 11.34 gm/cm-2. Further the low melting points of lead (325° C.) prohibits its use in high temperature shielding structures and (ii) the use of Rare earth is restricted because they are very costly and scarcely available. The novel process of the present invention utilizes different varieties of waste as raw materials such as fly ash (from thermal power plants), Red mud (from aluminum production), Rice husk silica (an agro waste) and pyrophyllite (an underutilized clay mineral). These waste materials contain various necessary constituents required for making radiopac materials namely silicon, titanium, iron and aluminum.
    Type: Application
    Filed: January 3, 2005
    Publication date: March 30, 2006
    Inventors: Sudhir Amritphale, Navin Chandra, Narayanrao Ramakrishnan