Ariver with 400 ppm of salt (a conservative substance) and an upstream flow of 25.0 m3 /s receives an agricultural discharge of 5.0 m3 /s carrying 2,000 mg/l of salt. the salt quickly become uniformly distributed in the river. a municipality just downstream withdraws water and mixes it with enough pure water (no salt) from another source to deliver water having no more than 500 ppm salt to its customers. what should be the mixture ratio f of pure water to river water?

what best describes physical development during adolescence is the development of secondary sex characteristics happens at a rate unique to each individual.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia