Resistance is a measure of a material’s tendency to resist the flow of an electric current and depends on material composition, thickness, length, and temperature. Ohm’s law states that electric current equals voltage divided by resistance. Resistance generates heat and is used for electric heating, cooking, and lighting. Resistors and fuses protect delicate components from […]
Vascular resistance is affected by the diameter, length, and viscosity of blood vessels. Vasoconstriction increases resistance, and there are two types: systemic and pulmonary. High blood pressure is caused by increased vascular resistance or cardiac output and can lead to serious conditions. Medications and lifestyle changes can help manage hypertension. Vascular resistance describes the degree […]
Resistance welding uses heat and pressure to bond materials, including metals and plastics. Copper electrodes inject heat, which can be controlled by the operator. Pressure is also necessary for cohesion. Spot and seam welding are examples of this process, with different electrode shapes used for each. Different types of resistance welding include fusion bonding and […]
Contact resistance measures the flow of electricity or heat between two surfaces, with larger surface areas having lower resistance. Gold and soft metals are often used in contact pads. High resistance can be caused by loose connections, erosion, contamination, or corrosion. Ohmmeters can test resistivity, taking into account surface area and pressure. Manufacturers provide measuring […]
Activated protein C resistance is a hereditary blood disorder that causes abnormal venous thrombosis. Treatment involves heparin injections followed by oral warfarin therapy. The disorder is caused by a mutation in coagulation factor V, which makes it immune to activated protein C. The risk of developing thrombosis is increased in people with inherited activated protein […]
Resisting arrest is when someone interferes with a lawful arrest. It’s an offense in most countries, but charges can be challenged if the arrest was not lawful or if excessive force was used. Interfering with an arrest can also lead to charges, but bystanders can’t be charged with resisting arrest. It’s difficult to fight charges […]
Thermal resistance measures a material’s ability to resist heat transfer, often applied to buildings for insulation effectiveness and energy efficiency. R-value is used to measure thermal conductivity and resistance, with higher values indicating greater resistance. Homeowners should look for materials with high R-values, such as fiberglass or wool blankets, but must ensure proper installation and […]
Electrical resistance impedes the flow of electric current and is measured in ohms. Resistance is affected by material structure, geometric composition, insulation quality, impedance, and density. There are two types of resistance: direct current (DC) and alternating current (AC). Excessive resistance creates heat and can be dangerous. Electrical resistance is a force or material that […]
Pièce de résistance is a French term meaning the highlight or most impressive thing. It was first used in English in the mid-19th century to describe the final dish of a meal. It can also be used to describe the highlight of a collection, an actor’s performance, or a memorable moment. It can be used […]
