Various Definitions

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Ultrasonic sound- The PING))) ultrasonic sensors operate using ultrasonic sound. The sensor emits an ultrasonic chip, which is reflected off of and object. The sensor times how long it takes for the sensor to emit the chirp, and have it received off the object as an echo. Using the equation of the speed of sound in air, the sensor monitors distance. The sensor operates using a 40kHz chirp. This frequency falls in the sound range commonly used by animals for communication. Frequencies that are much higher, for example 1-20 mHz are used more commonly for medical imaging. PCB- This first ever PCBs started out of materials such as layered cardboard and masonite. During the 1950's and 60's, the concept of using different resins and mixing them with various materials was beginning to be introduced, however, all boards were still one-sided. The government’s development of new equipment in both the weapons and communication fields had a large effect on the progress and advancement of the board. The early boards also held components and leads using small nickel plates, soldered to the board. Eventually both sides of the boards were able to electronically connected by processes that were developed that plate copper onto the walls of the drilled holes. Also, brass was the metal used in the early boards, but was later replaced by copper due to its ability to carry an electric current more efficiently and more cost effectively that brass. Relay switch- Electrical relay switch are operated using electrical currents flowing through a coil, creating a magnetic field which attracts a level. The position of the level is based on whether or not the electric current is on or not. And because the current is able to be turned on and off, you get two ... ... middle of paper ... ...ycelium a stem like structure forms called the sporangiophores and atop this is where the sporangium is. The sporangia are big clusters of spores. when the sporangium gets big enough the spores are released. spores are the "seeds" of rhizopus. when the spores are released and swept away by the wind or any moving force the spores land and germinate and start a new fungal body. Aspergillus niger- Aspergillus is a common black mold found growing on other plants in humid areas. there are many different kinds of Aspergillus and there mycotoxins range in toxisity. Aspergillus is also very important in the food industry as it is the biggest source in producing citric acid. Aspergillus also like motioned before has strains that are very hazardous to our health. for instance Aspergillus when inhaled some strains can cause upper respiratory illnesses such as aspergillosus.
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