You may not think of salt and sugar as solids because when you see them in the kitchen they are such small particles. But each of these particles is as much a solid as a wooden table, a glass window, or a gold piece of jewelry. A solid is a collection of atoms or molecules that are held together so that, under constant conditions, they maintain a defined shape and size.
Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off.
Human Resource Management (HRM) is the term used to describe formal systems devised for the management of people within an organization. The responsibilities of a human resource manager fall into three major areas: staffing, employee compensation and benefits, and defining/designing work. Essentially, the purpose of HRM is to maximize the productivity of an organization by optimizing the effectiveness of its employees.