Define process, input, output, process variable and process stream.

 Process: A process refers to a series of actions, operations, or changes that convert raw materials or inputs into a desired product or output. It can be a chemical reaction, a physical transformation, or a combination of both.

Input: Inputs are the raw materials, energy, or other resources that are used as inputs for a process. They can be in the form of raw materials, fuel, or other inputs needed for the process to take place.

Output: Outputs are the final products or results obtained from a process. They can be in the form of goods, energy, or other forms of outputs that have been transformed or created through the process.

Process Variable: Process variables are the measurable or controllable parameters that affect the performance of a process. They can include temperature, pressure, flow rate, and other variables that can be measured or controlled to optimize the process.

Process Stream: A process stream refers to the flow of materials, energy, or other inputs and outputs within a process. It can include multiple inputs and outputs, as well as various process variables that affect the overall performance of the process.