Delignification is the process of removing lignin from wood pulp to ensure paper brightness and clarity. The Kraft process and oxygen delignification are commonly used, with the former being more effective. Lignin is an essential element in wood structure but causes staining in papermaking. Delignification is a group of industrial processes in which lignin, the […]
Blast furnaces are used in iron smelting, with a tower shape and safety doors for feeding raw materials. They combine coal, iron ore, and flux to produce pig iron, and have remained largely unchanged since the Middle Ages. Blast furnaces are still an important part of the steelmaking process and are relatively inexpensive to operate […]
Thermoplastic resin is a polymer that becomes fluid when heated and solidifies when cooled, used in molding processes such as injection molding to create consumer products. It dates back to the mid-1800s and is commonly used in polyethylene, polypropylene, polyvinyl chloride, polyester, polystyrene, and polycarbonate. Injection molding is the most common use, but it can […]
Pack rolling is a process used to produce multiple sheets of thin film simultaneously, with advantages including the ability to use conventional rolling equipment and increased tenacity. The process is commonly used to produce aluminum foil for various industries and results in a shiny and dull appearance on either side. Raw sheets must be oiled […]
Dual voltage electronics can recognize and use American and European currents without a transformer. It’s popular in portable devices and will eventually be the standard. Check for a stamp or tag specifying “110V-240V” and never force a plug into an outlet. Dual voltage is a term used to describe any type of electronic device manufactured […]
DC power supplies have a positive and negative terminal, with the positive terminal receiving a positive electrical charge. The polarity relationship is marked by the universal color code and symbol, with correct polarity essential for connecting DC devices to a power supply. Reverse polarity can be used to change device operation, but failure to observe […]
Drill rods made of high carbon steel are used to make various tools and bearings. They come in different diameters and can be water or oil-hardened. Water-hardened rods are easier to work with but not suitable for welding, while oil-hardened rods are tougher and can be welded. Hardening is done by heating and cooling the […]
A magnetohydrodynamic (MHD) drive uses an electromagnetic field to accelerate a charged fluid, creating thrust without moving parts. The Lorentz force can be harnessed for propulsion in spacecraft, but requires a lot of power. MHD motors are reliable, efficient and quiet, but require a heavy on-board generator that burns diesel. MPD thrusters have extremely high […]
Electroplating is an electrochemical process used to coat objects with a thin layer of metal. It has various applications in industries such as jewelry making, automotive, and electronics. The process involves placing a negative charge on the object, dipping it in a saline solution of the metal, and controlling the thickness of the plating by […]
O-rings are round rings made of materials like polyurethane, silicone, neoprene, nitrile rubber, or fluorocarbon. They are used in mechanical applications to create an airtight seal between two objects. O-rings are inexpensive and can withstand high pressure. They are used in various industries, including space and aircraft. Different types of O-rings are used for different […]
A ball valve is a quarter-turn valve with a ball that controls fluid flow. It can be two-way or three-way, and is controlled by a handle. It’s good for shutting off streams, but not precise control. There are three types: full bore, standard port, and small-port. A ball valve, a type of quarter-turn valve, is […]
Manholes connect underground utilities to the surface and have covers that allow easy access for maintenance. Some lead to underground vaults, while others connect to a series of pipes. Manhole covers are typically round and can provide a pictorial history of the utilities in a city. A manhole, or maintenance hole, is a pipe that […]
“Super magnets” are neodymium magnets or powerful electromagnets used in fMRI imaging. They are much stronger than ferrite magnets and can be hazardous to pacemaker wearers. Neodymium magnets are made of an alloy of neodymium, iron, and boron and can hold 1300 times their own weight. They have various uses but must be used with […]
Orbital welding uses an automatic rotating arc to join objects with little room for user error. Special equipment is needed, including a non-consumable electrode and a power and control system. This technique is popular in cleanroom applications and requires a variety of welding heads to fit different objects. Orbital welding is a method of joining […]
Fixed capacitors maintain a constant charge and energy output, and are commonly used in timing circuits and small electronics. They are made with a dielectric material that separates conducting plates, and come in various shapes and sizes with different nominal capacities. Capacitance is measured in farads or microfarads. The history of capacitors dates back to […]
Radiographic testing uses electromagnetic waves to detect defects in materials without damaging them. X-rays or gamma rays are used to send waves through the material, and changes in the waves are measured to identify defects. This method provides a film record of the results and is commonly used to test welds, building materials, and spacecraft […]
Foundation cracks can be serious and require assessment to determine the cause and necessary actions. Cracks in concrete, poured concrete, and cinder block foundations may be caused by shrinkage, while brick walls can crack due to moisture or settling. Stone walls can crack due to explosions or heavy traffic. Diagonal cracks may be caused by […]
Power plants generate electricity by burning fossil fuels to produce steam, which turns a turbine to create electrical energy. Coal is the most commonly used fuel, but it produces harmful emissions. Other power plants use nuclear reactors or geothermal energy. Renewable energy sources like wind and solar are becoming more popular. A power plant is […]
Flexible couplings allow for adjustable joints between inflexible pipes or shafts, maintaining torque or fluid flow while allowing for misalignment. Examples include universal joints and stainless steel mesh sleeves for pipe fittings. They are useful in automobile exhaust systems and front wheel drive vehicles. A flexible coupling is a mechanical device that allows an adjustable […]
Natural gasoline is a liquid form of natural gas that can be obtained by fractional distillation or from condensates. It consists of hydrocarbons like butane, pentane, and hexane, and was used as a fuel source for early automobiles and airplanes. It has a low octane rating and can be volatile, but can be combined with […]
