Nanotechnology and microfabrication Essay Example | Topics and Well Written Essays - 1000 words

Nanotechnology and microfabrication - Essay Example Due to carbon’s wide applications, it is not surprising that it is also a key component in the rising field of nanotechnology. Beside its natural occurrence in the form of graphite and diamond, carbon exists in the nanostructured forms of fullerenes or buckyballs and in carbon nanotubes. The beauty of carbon nanotubes formed by carbon atoms is that they are twofold stronger than steel but weigh six times less. Carbon nanotubes are allotropes of carbon that have been first constructed by S. Iijima in 1991. These are significantly extended thin cylinders and large macromolecules of carbon with unique features in their shape, size and physical properties as well as having the highest ratio up to 28,000,000 between length and diameter (Zheng, 2004). This is larger than any other material in the world. They can be envisioned by taking a mass of graphite into consideration that is rolled into a cylinder shown as Appendix-I figure (i) on page 6. These fascinating structures have flashed world wide great excitement and appraisal during last few years. Currently a huge amount of money is being spent on these carbon nanotubes to improve the understanding of their properties. Still its physical characteristics are being discovered and controversial results are being obtained. The development and research on synthesis methods is considered as a vital step to the future outlook of carbon nanotechnolog y. The structure of a carbon nanotube can be envisioned by taking a mass of graphite into consideration that is rolled into a cylinder as shown in figure (i) on page 6. Nanotubes, on the basis of the direction of hexagons, are classified as zigzag, armchair or chiral and are shown as Appendix-I figure (ii) on page 6. There are two types of carbon nanotube i.e. single-walled nanotubes (SWNT) and multi-walled nanotubes (MWNT). Generally SWNT are composed of a diameter close to1 nanometer while the tube length that can have a length millions of times longer and are excellent

Race in wold war II Essay Example | Topics and Well Written Essays - 250 words

Race in wold war II - Essay Example However, the situation at America and other European powers at home was same that consisted of discrimination against all ethnic minorities and their segregation from  the mainstream  of the society.   When America announced its participation in Second World War, most of the members of the ethnic minorities were divided regarding joining army to defend their country. There were many members of ethnic minorities, who had joined in serving their country during World War I in hopes, that government would treat them equally after winning the war.  However, the government did not fulfil their hopes (Jepson). Some people joined  voluntarily,  and some people were drafted in the service.  However, the discrimination treatment continued in Army.   Most of the Black people and others were assigned menial job. They were drivers, cooks and others. The officers and others continued to show contempt and discriminated against them at every given opportunity. There were very few black soldiers who fought side by side in Pacific or other war theatres.  However, they proved to be very good  organizers,  and they changed the results in allies favour with their ingenuity.  However, they were also discriminated against by the people whom they defended in Europe as well as in Pacific (Jefferson). The main aspect of life where the attitude towards the race affected in war was the indifference shown by  the large  number of members from ethnic minorities in America.  There were very few people who were interested in joining defense  services  and serve  their country (Jefferson). Most of the veterans who had participated in previous war stayed at home. The soldiers who  learned organizational  skills in the army used them to organize various movements back home for equal rights and facilities.   Jefferson, Robert F. Fighting for Hope: African American Troops of the 93rd Infantry