1st Generation Pesticides: 1  2500 BC- farmers began using the toxic chemical sulfur to kill off pests from their crops. 2  15th century AD -a variety of chemicals such as, arsenic, hydrogen cyanide, mercury and lead were put to use. 17th century -nicotine sulfate, derived from tobacco leaves was discovered as an effective pesticide and ants were controlled with mixtures of honey and arsenic.
Cell phones communicate with nearby cell towers mainly through radiofrequency (RF) waves, a form of energy in the electromagnetic spectrum between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, they are forms of non-ionizing radiation.
There is no standard way for cell phones to represent the signal strength. Or maybe there is one - it is called dB gain or decibel gain. dB-gain is the most accurate way to measure the strength of a cell phone signal. dB Gain and your Cell Phone Signal Booster The best way to measure the cell phone signal strength is as decibels or dBgain because it is most accurate without flip flops at one time and place. A -50dB represents a really strong signal or full bars and a -110 dB represents a weak or dead signal or no bars.