Essay Examples on Quinsigamond Community College

Synthetic aperture radar SAR is a unique and well-Established Approach

Synthetic aperture radar SAR is a unique and well established approach for remote sensing providing high resolution digital images independent of daylight or cloud coverage Space borne SAR systems such as the current RISAT 1 RADARSAT 2 and Sentinel systems continuously yield data from extensive area of the globe with a revisit time in order of days Airborne systems on the other hand map on a more local scale but can offer lower revisit times with higher resolutions The utilizations for the acquired SAR data range from mapping of land use forest water agriculture urban to change detection based on time series monitoring of sea ice marine surveillance traffic monitoring soil moisture and biomass estimation and quick response mappings to support humanitarian aid in crisis situations A SAR system is not simply a tool for remote feature detection but it is also a measurement instrument to record reflectivity As for any other measurement instrument system calibration is hence necessary to ensure that different SAR acquisitions are comparable to each other Calibration in SAR is a cornerstone for scientific applications as well as for verifiably reliable products for a growing commercial market The SAR calibration activities are usually split into geometric and radiometric calibration In geometric calibration the SAR image coordinate system is compared with a reference coordinate system and corrections are determined and applied to ensure that SAR images are geo located with respect to a known coordinate system 

2 pages | 474 words

X-Ray studies and Radiation Protection

Since the beginning of the 20th century ionizing radiation starts playing a very important role in medical diagnostics and medicine There was a need for radiation safety during X ray studies and radiation protection of personnel In this connection it s very important to understand the essence of ionizing radiation and how ionizing radiation interrelate with biological matter X ray radiation that is generated by diagnostic devices poses a certain danger to personnel patients and people in neighbouring rooms In this regard their operation and placement must comply with the requirements of radiation safety Two of the most important ionizing regulations in the UK is IRR99 and IR MER 2000 Another very important document is the Policy for the Use of Ionizing Radiation in which local rules are indicated 2 As state in physic central Ionizing radiation is any type of particle or electromagnetic wave that carries enough energy to ionize or remove electrons from an atom There are two types of electromagnetic waves that can ionize atoms X rays and gamma rays Humanity on the earth has constantly been exposed to natural sources of ionizing radiation radon gas and cosmic rays for example as well as human made sources in modern days X ray machines nuclear power generation Depending on the dose received radiation exposure can have a negative impact on human health The unstable atoms of ionizing radiation like Alpha Beta and Gamma rays can damage DNA and the structure of cells Passing through cells ionising radiation destroys their biological processes

2 pages | 501 words