月: 2023年3月

What Is a Fractionator?

A fractionator is a sophisticated device designed to separate mixtures of liquids into individual components based on their boiling points. Utilizing the distillation process, it repeatedly condenses and evaporates the mixture to achieve separation and purification.

Uses of Fractionators

Fractionators play a vital role in industries such as petroleum refining and chemical manufacturing. They separate crude oil into usable products like gasoline, kerosene, and diesel, and are essential in producing high-purity gases from liquid air.

Principle of Fractionators

Operating on the principle of fractional distillation, fractionators differentiate liquids in a mixture by their boiling points. They are specifically designed to handle liquid mixtures, unlike general distillation processes that may apply to solids or gases as well.

Azeotropic mixtures, which cannot be completely separated due to their identical gas and liquid phase compositions, pose challenges that require specialized separation methods.

Structure of Fractionators

The core structure of a fractionator includes a multi-stage fractionator tube which allows for the efficient separation of components by boiling point. Various designs like the Bee-Glo, Hempel, and Schneider tubes cater to different separation needs, minimizing contamination and improving purity.

Other Information on Fractionators

1. Crude Oil Fractionation Process

The fractionation of crude oil involves heating the oil and then separating its components in a fractionating column based on their boiling points, from heavy residues like asphalt to lighter products like gasoline and naphtha.

2. Components Separated by Fractional Distillation of Crude Oil

Different sections of the fractionating column yield various petroleum products, with heavier components collected at the bottom and lighter ones, including valuable gases, at the top.

What Is a Steamroller?

A steamroller is a machine used in pavement construction.

Steamrollers are used in different ways, depending on the structure of the pavement and the construction process. The basic structure consists of four layers, starting from the one closest to the ground: “roadbed,” “base layer,” and “surface layer.” The structure also varies depending on the pavement specifications, including the most familiar asphalt pavement, concrete pavement, and special pavement.

The construction procedure for each layer is determined, and the appropriate steamroller for the job is used.

Uses of Steamrollers

The steamroller used in the paving process varies along with the pavement specifications. Each layer created by the steamroller has its own role. The first roadbed transfers the load of the upper three layers to the ground and is made mainly of soil.

The roadbed is responsible for distributing the loads of the top two layers, and there are two layers of crushed stone containing cement, lime, etc., the top layer and the bottom layer. The base layer is responsible for correcting the unevenness of the roadbed and is a layer of asphalt, sand, etc.

The last surface layer is asphalt or concrete, which distributes the load of vehicles passing over it. Steamrollers are used to ensure that each layer performs its role properly.

Principles of Steamrollers

The following are the principles and methods of steamroller used for each paving process.

1. Roadbed Construction

Roadbed is to flatten and consolidate the ground. This prevents the roadbed from settling due to the weight of vehicles and other objects passing over it. A bulldozer is an earth-moving machine that excavates, fills, and levels the ground, using its front blades to push and remove earth and sand.

Motor graders are used to level the ground by tilting the blade installed under the body against the direction of travel. Tire rollers and road rollers are used to compact the soil by rolling it under their own weight. In addition to the dead-weight type, vibratory road rollers are also available.

In roadbed construction, a bulldozer is used first to level the roadbed, and a motor grader is used for the final leveling. Next, tire rollers are used for compaction, and finally, road rollers are used for hardening.

2. Roadbed Construction

The roadbed work uses the same earth-moving equipment as for roadbed construction. In roadbed construction, crushed stone materials are first unloaded from dump trucks.

Next, a bulldozer is used for rough leveling, and a motor grader is used to spread the material to the specified finished thickness. Then, tire rollers and road rollers are used for compaction and spreading to the specified density. 

3. Base Layer and Surface Layer Construction

The asphalt finisher is a self-propelled steamroller. As a specialized steamroller for asphalt paving, it is used for both base layer and surface layer work. It consists of a hopper for storing asphalt mixture, a prime mover, a tractor section for traveling equipment, and a screed for spreading the asphalt mixture evenly.

First, the asphalt mixture transported by dump trucks is stored in the hopper. Next, the mixture is fed backward by a bar feeder at the bottom of the hopper, spread to the left and right by a screw, and spread evenly by a screed. The angle of the screed can be varied to increase or decrease the amount of asphalt and to change the thickness of the spread.

Surface work using asphalt finishers involves two processes: leveling and compaction. Spreading is the process of spreading the asphalt mixture. Compaction is the process of repeatedly compacting the spread to create a firm base.

Finally, it is finished by rolling with tire rollers or road rollers.

Other Information on Steamroller

Concrete Steamroller

For roadbed and roadbed construction, the Steamroller required for concrete paving is the same as for asphalt paving. An asphalt intermediate layer is placed on top of the roadbed, and a concrete slab is formed on top of the asphalt.

To form the concrete slab, concrete is generally transported by mixer trucks and poured by concrete pump trucks. In addition to ordinary concrete pavement, there are other methods to overcome the disadvantages of concrete pavement, such as continuous reinforced concrete pavement and compacted concrete pavement.

In recent years, asphalt pavement has become the majority and the percentage of concrete pavement has declined. Concrete pavement has advantages and disadvantages compared to asphalt coating, and its adoption is for special locations.

Concrete pavement is used in tunnels, steep roads, airport aprons, container yards, etc. because of its superior durability and service life.

What Is Caulking?

Caulking is a product used to fill cracks and gaps in structures caused by impact, fatigue, or age-related deterioration, to maintain waterproofing performance and strength.

Caulking is a type of adhesive that can be injected into cracks or holes to expose them to air, or mixed with the main and hardening agents to fill holes and repair strength. However, there are also many products that are designed to be flexible after curing rather than for adhesive purposes, assuming that holes will be drilled or painted after use.

Applications of Caulking

Caulking is widely used for repairing buildings and machinery.

Cracks and design gaps in concrete, plastic, metal, and other materials require immediate repair because they cause aesthetic damage, loss of strength, leakage, and other problems.

Caulking can be injected into the target surface to restore lost aesthetics and functionality as a post-repair measure, and also to prevent the progression of deterioration due to the intrusion of moisture and other deterioration factors.

For surfaces with more advanced deterioration, it may be necessary to seal the surface only, without injecting into the pore spaces.

Principle of Caulking

Caulking is based on the principle that silicone resin, epoxy resin, etc. react with moisture in the air or polyamine or polyamide to cure.

In the case of silicone resin, there are alkoxy groups on the surface, which hydrolyze with moisture in the environment and cross-link to form a rubber elastic body. In the case of epoxy resins, the epoxy groups in the molecule react with polyamine and polyamide to create a cross-linked structure. However, because strong amide bonds are created in the molecule, the adhesive strength becomes stronger and harder.

When strength is required in caulking for repairing vehicles and buildings, strong bonds such as epoxy resins are suitable. However, they are not suitable for use on plastic surfaces or for post-repair processing. If adhesion to the surface or the use of soft materials is required, silicone resins with excellent elasticity are suitable.

Modified silicone resins, in which some of the methyl groups in the molecule are replaced with functional groups, are an improved version of silicone resin.

What Is a Heat-Dissipating Sheet?

A heat-dissipating sheet is a sheet that easily conducts heat (good thermal conductivity) and is sometimes called a thermal conductive sheet.

Resin materials such as silicone and polyolefin are often used for the sheets, and some sheets contain fine metal powder called metal filler to enhance thermal conductivity. Recently, heat-dissipating sheets made of carbon, commonly known as carbon fiber-based sheets, are also on the rise.

When you want to insulate electrically while maintaining thermal conductivity, a fine ceramic powder called ceramic filler can be added to provide electrical insulation.

Applications of Heat-Dissipating Sheets

Heat-dissipating sheets are not only used in personal computers and home appliances but also in a wide range of products, such as analyzers, etc. In addition to electronic components that generate a lot of heat, such as CPUs, heat-dissipating sheets are also used to raise the temperature of objects that are uneven, taking advantage of their soft characteristics.

Heat-dissipating sheets are not only directly attached to the object to be dissipated and dissipate heat into the air through the heat-dissipating sheet, but are also used to cool the object efficiently by being attached between the substance to be dissipated. A metal heat sink, such as aluminum or copper, which has high thermal conductivity, is used.

Heat-Dissipating Sheet Principle

In addition to heat-dissipating sheets, other devices for heat dissipation include heat sinks, heat pipes, and heat-dissipating blocks, which are mainly made of metal and have higher thermal conductivity than heat-dissipating sheets. However, because they are made of metal and are hard, they do not adhere well to the object to be heated, and the air between them may cause poor heat conduction.

Heat dissipating sheets can improve the adhesiveness with the object to be dissipated, so it can be used not only by itself but also between a metallic heat dissipating device and the object to be dissipated to improve the efficiency of heat dissipation.

In addition to heat-dissipating sheets, there is also heat-dissipating grease that improves adhesion. Since heat-dissipating grease adheres to fine surface irregularities, no air layer is allowed to enter, resulting in high thermal conductivity. However, grease is subject to large variations in thickness and thermal conductivity. Heat-dissipating sheets, on the other hand, are simply applied. Therefore, there is no variation in thickness, and the thermal conductivity is stable.

What Is Heat Dissipation Material?

A heat dissipation material is a material used to facilitate the escape of heat from components that require temperature control.

Heat dissipating materials are used in gel, compound, filler, adhesive, and sheet forms for various products.

The heat generated in electronic components not only slows down the operation of electronic products but also causes malfunctions and failures.

Heat dissipation material has been developed with an emphasis on how to facilitate efficient heat dissipation, especially in recent years with the emergence of high-performance electrical products that handle large amounts of data.

Applications of Heat Dissipation Material

Heat dissipation material is mainly used inside electrical products.

These products are used in a wide range of fields, including IT, industrial equipment, home electronics, automobiles, and power devices.

Applications include CPUs on motherboards, where heat is generated when electricity is applied and the temperature rises rapidly, resulting in high temperatures.

In particular, the amount of heat generated varies depending on the characteristics of the product, the time it is used, and its combination with other components.

Therefore, the amount of heat generated is calculated in advance by simulation, and the higher the amount of heat generated, the higher the Heat Dissipation Material to be used.

Principle of Heat Dissipation Material

Heat dissipation material is a material closely related to the physical properties of thermal energy.

Thermal energy is converted by physical actions, such as the flow of electricity, to energy that raises the temperature of an object.

Therefore, to lower the temperature of an object, thermal energy must be transferred outward, which means that heat must be released to the outside world, the so-called air layer.

However, since the air layer has low thermal conductivity, it is not easy to release heat from a hot object. Heat dissipation material plays this role.

Heat dissipation material is a material with high thermal conductivity. When applied or adhered to a high-temperature component, such as a CPU, the heat is transferred to the heat dissipation material.

Heat dissipation material is in contact with the air layer, so the heat accumulated in the heat dissipation material is dissipated into the air layer.

Heat dissipation material is shaped to have a large contact area with the air to facilitate heat transfer to the air layer.

This process is used to lower the temperature of electronic components to prevent them from malfunctioning.

What Is a Bullet-Type LED Diode?

A bullet-type LED diode is a type of light-emitting diode (LED: Light-emitting diode) device package that is cylindrical with a hemispherical top. It is named “bullet-type” because of its resemblance to a bullet.

It is also called “through-hole mounting type” or “lead frame type” because the LED leads are passed through the component insertion holes on the printed circuit board and mounted by soldering.

The bullet-type LED diode is the oldest type of LED element package. Currently, surface-mount LEDs are the mainstream, and the number of bullet-type LEDs in the market is decreasing year by year.

Uses of LED Diodes

An LED diode has the characteristic of emitting light far in the forward direction and almost none in the side direction. Therefore, taking advantage of the feature of emitting light in one direction, they are used in various places, such as indicators, signs, signals, billboards, and information displays.

The bullet-type LED Diode was often used for general lighting in the past. However, when the surface-mount type LED appeared, the surface-mount type replaced the bullet-type LED as the mainstream for general lighting because it is brighter and has better heat dissipation performance than the bullet-type LED.

Principle of the Bullet-Type LED Diode

A bullet-type LED diode consists of a lead frame with a 0.3mm LED element of each size fixed to it, the anode (positive) terminal, and the LED element connected by bonding wire, and then sealed with a bullet-shaped encapsulating resin. The cathode (negative) terminal comes directly from the lead frame.

The bullet-shaped encapsulating resin not only protects the LED diode but also allows adjustment of the emission color by mixing phosphors in the resin and also serves as a lens. The size of a bullet-type LED Diode is indicated by the diameter of the lens portion, which is generally 3mm or 5mm.

An LED diode is a two-terminal device consisting of an anode terminal and a cathode terminal. The anode terminal is slightly longer than the cathode terminal to help identify the terminals. The anode side is connected to the positive side of the power supply and the cathode side to the negative side. The LED will not light up when connected in reverse.

LEDs are characterized by their low heat generation compared to light emitters, such as light bulbs. Although energy that is not converted into light is still released as heat. Since the LED diode only propagates the heat released by the LED element via a thin lead frame, it has poor heat dissipation and cannot conduct a large current.

What Is a Hydraulic Disc Brake?

A hydraulic disc brake is a friction brake system that uses hydraulic pressure to clamp a disc (rotor) with brake pads, slowing or stopping rotational motion. Key components include the brake disc, brake pads, and calipers.

Uses of Hydraulic Disc Brakes

Widely used in automobiles, motorcycles, bicycles, and aircraft, hydraulic disc brakes are favored for their stable braking force, high controllability, and superior heat dissipation. They are also employed in industrial machinery to halt large inertial bodies, like flywheels and centrifuges.

Principle of Hydraulic Disc Brakes

Hydraulic disc brakes leverage Pascal’s principle to amplify the force applied by the operator into a greater braking force. This system transforms kinetic energy into heat energy through friction between the brake disc and pads, effectively slowing down the vehicle.

1. Hydraulic Principle

By applying Pascal’s principle, a small force applied to the brake pedal is magnified through hydraulic pressure, allowing for significant braking force with minimal effort.

2. The Principle of the Disc Brake

The disc brake system relies on the frictional force between the brake disc and pads to convert kinetic energy into heat, which is then dissipated into the atmosphere.

Types of Hydraulic Disc Brakes

Hydraulic disc brakes come in opposed and floating types. The opposed type, with pistons on both sides of the disc, offers higher braking force and controllability. The floating type, with pistons on one side, is lighter and more cost-effective.

Features of Hydraulic Disc Brakes

Hydraulic disc brakes provide precise control and are designed to be proportional to the force applied by the piston. They outperform drum brakes in heat dissipation, water resistance, and reducing water fade due to their exposure to the atmosphere and structural design.

Disc brakes are available as solid or ventilated, with the latter offering enhanced heat dissipation. In contrast, drum brakes tend to retain heat and have a self-multiplying effect that can make them less controllable.

What Is a Hydraulic Unit?

A hydraulic unit is a device that supplies oil with a certain pressure to drive a machine that requires more power.

An oil tank, motor, pump, etc., are combined to push oil. First, an external electric motor drives the hydraulic pump, and then the propagated hydraulic pressure is used to move the actuators (hydraulic motors and cylinders) to generate work.

The amount of oil discharged depends on the speed, power, size, and number of actuators. The output pressure can also be controlled by the actuator.

Applications of Hydraulic Units

Hydraulic units are used to drive many types of construction equipment, industrial vehicles, and agricultural machinery. Typical examples include excavators, forklifts, tractors, and dump trucks.

They are also used in industrial machinery, such as iron and steel-making machinery, machine tools, and injection molding machines.

Since these large machines need to exert power efficiently with less power, the power output technology using hydraulic units has become indispensable in today’s industrial field.

Principle of Hydraulic Units

Hydraulic units use the power of hydraulic pressure to generate physical pressure that is difficult to produce by human power.

This mechanism is explained by Pascal’s principle.

Pascal’s principle states that when pressure is applied to a liquid enclosed in a sealed container, the pressure propagates equally throughout the liquid.

Since a constant pressure propagates, the larger the cross-sectional area that the liquid touches, the greater the applied force.

For example, two pistons with different cross-sectional areas are connected by a tube, and the liquid is enclosed in the tube.

When the piston with the smaller cross-sectional area is pushed into the liquid, the pressure propagates through the liquid, and the piston with the larger cross-sectional area is lifted. As a result, a larger force is applied to the larger piston.

Thus, even if less force is applied, a greater output can be obtained. Hydraulics also utilize a similar principle.

Since oil is used as the medium, the direction of force can be freely changed according to the shape of the hydraulic cylinder. It is also easy to divert the flow in piping. Furthermore, the size and speed of the force can be easily adjusted.

What Is a Macromolecule?

Macromolecules, also known as polymers, are large organic molecules with a molecular weight of over 10,000, primarily composed of carbon along with elements like oxygen, hydrogen, and nitrogen. They are categorized into synthetic macromolecules and biopolymers.

Since their conceptualization in 1917, macromolecules have been central to advancements in materials science, leading to a variety of applications, especially during World War II.

Uses of Macromolecules

Macromolecules serve as the foundation for a wide range of products, from synthetic plastics and fibers to biological DNA and proteins. They are critical in manufacturing, medical materials, and everyday products due to their versatile properties like strength, heat resistance, and transparency.

Principles of Macromolecules

Macromolecules are formed by polymerization, where small molecules (monomers) bond together. This process can vary, resulting in diverse structures and properties among macromolecules, depending on the monomers and polymerization methods used.

1. Chain Polymerization

A process where monomers link into long chains, categorized by the type of initiating active species into radical, anionic, and cationic polymerization.

2. Sequential Polymerization

Monomers with multiple functional groups react to form intermolecular bonds, leading to chain elongation. This includes polycondensation, polyaddition, and addition-condensation reactions.

Types of Macromolecules

Macromolecules vary widely in properties based on their monomer composition and molecular weight. For example:

1. Chain Polymerization

Examples include polyethylene (PE), polypropylene (PP), and polystyrene (PS).

2. Sequential Polymerization

Examples include polyethylene terephthalate (PET) and polyamide (PA).

What Is an Emergency Light?

Emergency lights are lights that indicate evacuation routes in the event of an emergency.

They are required to be installed in facilities with numerous people inside and with specific installation standards. 

Emergency lights near emergency exits are accompanied by a sign. Most of them have a green background with a picture of a person jumping out of a door and are one of the most widely known signs.

Emergency lights are graded according to their dimensions. The grade used depends on the floor area of the building.

Uses of Emergency Lights

In the event of an earthquake, power failure, or fire, induction lights are installed so that third parties can evacuate to a safe place. 

Emergency lights are classified into three categories: Emergency Lights for Evacuation Exits, Emergency Lights for Aisles, and Emergency Lights for Seats. Emergency Lights are used to indicate the presence of an emergency exit, while passageway emergency lights are installed to facilitate evacuation by stairs, etc. Emergency Lights for seats illuminate the feet of the audience and prevent them from lighting up to other areas, etc.

Principle of Emergency Light

Emergency Lights are mainly composed of a sign, a light, and a power supply.

The sign portion is used for emergency lights near emergency exits and is omitted for foot guide lights, etc. The power supply portion is used for emergency lights near emergency exits, etc. Highly permeable materials such as acrylic are used. Light from the lighting portion is transmitted through the back surface, making it easier to see even during power outages.

In the past, fluorescent lamps were used for lighting. Fluorescent lamps were lit via ballasts. However, due to the Mercury Pollution Control Law, many fluorescent lamps containing trace amounts of mercury were discontinued. In recent years, LED lamps have been widely used because of their low energy loss and simple structure.

The power supply part normally accepts commercial power to emit light, but in the event of a power failure, it switches with the battery part to supply power to the lighting part. Emergency Lights that function during disasters are required to operate for several tens of minutes on batteries.