Concerta and Adderall are medications used to treat attention deficit hyperactivity disorder (ADHD). These drugs help activate the areas of your brain that are responsible for focusing and paying attention. Concerta and Adderall are the brand names of generic medications. The generic form of Concerta is methylphenidate. Adderall is a combination of two generic drugs: amphetamine and dextroamphetamine. A side-by-side comparison of these two ADHD medications shows that theyâre similar in many ways. However, there are some differences.
NASA engineers have finished testing a new ion-propulsion system for earth-orbiting and interplanetary spacecraft. The system is more powerful and fuel-efficient than its predecessors, enabling it to travel farther than ever before. Ion propulsion works by electrically charging, or ionizing, a gas using power from solar panels and emitting the ionized gas to propel the spacecraft in the opposite direction.
Liquid motors come in many shapes and sizes: Most of them are controllable (can be throttled up and down), restartable, are often used as control and maneuvering thrusters. Liquid thrusters can be broken into three main types: monopropellant, bipropellant, and cryogenic thrusters. Monopropellants only use one propellant such as hydrazine. Bipropellants use a fuel and an oxidizer such as RP-1 and H. Cold-gas motors have controllability similar to liquids but are the simpler and lighter. They are basically a high pressure tank with switches which flip between the open and shut state.