投稿者: tama0512

What Is a Thermal Shock Tester?

Thermal shock testers are used to evaluate the resistance of electrical products to temperature changes in the environment in which they are used.

In the cold/heat shock test, a high-temperature and low-temperature environment is repeatedly and alternately created for a short period on the product to be evaluated, and the effect of the temperature change on the specimen is observed and evaluated to see if there are any problems. This test is often performed on automotive electronics products, such as audio and navigation systems in automobiles, and control motors in hybrid and electric vehicles.

Uses of Thermal Shock Testers

Thermal shock testers are mainly used in the evaluation of electronic products to verify their reliability. Among electronic device components, environmental resistance performance of soldered parts and plastic parts of various connectors are evaluated.

In addition, thermal shock testers are used for durability evaluations and failure reproduction tests as shown below.

• Reproduction test of cracks and solder cracks in solder joints
• Confirmation of durability evaluation by changing solder material
• Confirmation of durability of plastic connectors due to temperature change
• Confirmation of durability of bonding materials against cracking, peeling, and peeling of paint film
• Confirmation of durability against thermal distortion and cracking of resin molded parts such as connectors
• Check for defects caused by the difference in thermal expansion coefficients of different materials combined with resin and metal.
• Quality verification and screening tests for electronic device components

Principle of Thermal Shock Testers

Thermal shock testers are generally constructed in a three-layer structure with a high-temperature chamber above the test area, which serves as the test chamber, and a low-temperature chamber below. There are partitions called dampers that can be opened and closed between the test area and the high-temperature chamber, between the test chamber and the low-temperature chamber, and between the test chamber and the outside of the main unit.

When the test area is heated to a high temperature, the damper in the high-temperature chamber is opened and the damper in the low-temperature chamber is closed. In this state, air from the high-temperature tank is blown into the test area, enabling rapid heating of the test area. When cooling all at once, close the damper of the high-temperature chamber and release the damper of the low-temperature chamber, and then blow air from the low-temperature chamber into the test chamber.

When the test area is brought to room temperature, the dampers in both the high and low temperature chambers are closed and the damper between the test chamber and the outside air is released to bring the test area to room temperature. For testing electronic device components, it is also possible to conduct tests while the devices are energized.

The range of temperatures that can be set in thermal shock testers is approximately  -70 to 200 degrees Celsius. In recent years, quality requirements for electronic components have been increasing, and some testers are capable of testing temperatures up to 300°C.

Types of Cold Thermal Shock Testing

Thermal shock testing can be divided into a 2-zone test and a 3-zone test. 2-zone tests are performed under high and low temperature conditions, while 3-zone tests are performed under high and low temperature conditions plus room temperature conditions.

Normal temperature conditions are created by injecting air from outside the testing apparatus into the test chamber.

Other Information About Thermal Shock Testers

Necessity of Cold Thermal Shock Testing

Materials used in products expand and contract as temperature changes. Parts made of different materials will experience stress due to the difference in properties. This repeated process can cause fatigue to accumulate inside the product, resulting in cracks and fractures, which can break even with weaker-than-expected strength, splitting of joints, loosening of screws, and peeling of surface coatings.

Therefore, it is important to check the chronological order of expansion and contraction, along with the amount of load applied, to determine “where the load is applied that leads to breakage.” Cold and thermal shock tests are used to evaluate product performance and reliability.

In particular, power semiconductor components used to control motors in hybrid and electric vehicles are subjected to large amounts of electricity under severe environmental changes. Cold and thermal shock testing is essential to ensure that these electronic components do not malfunction in the marketplace.

What Is a Photocatalytic Deodorization Device?

Figure 1. Photocatalytic deodorization system

A photocatalytic deodorization device is a device that deodorizes the air by oxidizing and decomposing malodorous and harmful substances through the strong oxidizing power of photocatalysts supported on the filter. Photocatalyst is effective when light strikes its surface, oxidizing and decomposing harmful substances and odor-causing substances.

As a result, it exerts deodorizing and antibacterial effects and purifies the air. Although it has an oxidizing power stronger than ozone, it is safe and does not cause harm to the human body. This technology originated in Japan.

Photocatalysts can be used over and over again because they are voluntarily renewable by light. It is also characterized by its ability to maintain its effectiveness with simple maintenance and the fact that it does not need to be disposed of.

Uses of Photocatalytic Deodorization Devices

Photocatalytic deodorization devices are used to purify the air in the surrounding environment by installing them in places where bad odors are a problem. They can remove pollen, mold, tobacco, bacteria, and even viruses such as new strains of influenza.

They are often employed on the merit that they are safer than ozone and other substances. Therefore, it is mainly used in places where safety and hygiene are important. It is also used in university and corporate laboratories where animals and other animals are kept, food factories and kitchens, nursing homes, and hospitals.

It is also used in places where care is taken not to damage brands and images due to bad odors (large commercial facilities with many people coming and going, hotels and other lodging facilities). Because of its high oxidizing power and very strong deodorizing action, it is also used in places with very strong odors, such as sewage treatment facilities and sludge treatment facilities.

Principle of Photocatalytic Deodorization Devices

Figure 2. Principle of photocatalysis

Photocatalytic deodorization devices utilize the principles of photocatalysis and hydrodynamics. The principle of photocatalytic deodorization is an oxidative decomposition reaction.

　
1. When titanium dioxide (TiO2) is exposed to light (ultraviolet light), electrons in the valence band are excited, producing e- (electrons) and h+ (holes). 　
2. Oxygen and water in the air are adsorbed on the titanium dioxide surface, causing a redox reaction with h+ and e-, resulting in the generation of reactive oxygen species such as ・OH (hydroxyl radical) and O2- (superoxide anion). 　
3. The generated reactive oxygen species cause a redox reaction with organic compounds adsorbed on the titanium dioxide surface. Malodorous substances and bacteria are decomposed to produce carbon dioxide and water.

Compared to the oxidation potential of ozone, which is 2.07, the oxidation potential of titanium oxide, a component of photocatalyst, is 3.20. This indicates that the oxidation potential of photocatalyst is stronger than that of ozone.

Some products use the principle of hydrodynamics to devise an internal structure to make the pressure distribution more uniform, thus reducing the size of the device. Photocatalytic filters are constructed with two or three layers to increase the area where air comes into contact with the photocatalyst, thereby improving efficiency.

Types of Photocatalytic Deodorization Devices

Figure 3. Types of photocatalytic deodorizers

The structure of the product basically consists of a photocatalytic filter and a UV lamp. Filters carrying photocatalyst (titanium dioxide) include plastic, ceramic (alumina), and aluminum, and the number of filters varies depending on the product. Plastic is lightweight and resistant to breakage, ceramic is a thermally and chemically stable material, and aluminum is high-strength and lightweight, respectively.

They also come in a variety of shapes, such as directly above the fan, horizontally mounted, and ceiling-suspended types, and in sizes ranging from small enough to be installed indoors to large enough for outdoor use. Photocatalysts are self-regenerating by light, so maintenance of the photocatalyst itself is low maintenance. However, the UV lamps need to be replaced periodically.

When used for kitchen exhaust containing oily smoke, it is effective to select a product with a cyclone scrubber or grease filter as a pretreatment.

What Is an Eccentricity Measuring Instrument?

An eccentricity measuring instrument is used to measure the eccentricity, bending, or runout of a shaft or other object.

Eccentricity is defined as the misalignment of the center of a workpiece compared to the center point where it should be. In addition to workpiece eccentricity, runout, bending, concentricity, and coaxiality can also be measured.

Eccentricity is usually measured using a dial gauge. Center holes machined on both sides of the workpiece are clamped at both centers of the measuring instrument. The dial gage is set at the point to be measured and the workpiece is rotated for measurement.

In addition to the dial gauge method, there are other measurement methods such as reflective and transmissive methods using lasers and optics.

Uses of Eccentricity Measuring Instruments

Eccentricity measuring instruments are used to measure the eccentricity of rotating cutting tools, various arbors, crankshafts, gears, piston heads, etc. Eccentricity measuring instruments are also used to measure the eccentricity of lenses.

Parallelism between the top of the eccentricity measuring instrument table and both centers is assured. The structure is rigid to prevent errors caused by the weight of the workpiece or deviations over time.

The purpose of using eccentricity measuring instruments is usually to check accuracy after machining, such as cutting or grinding. In the case of bending measurement, it is used to check distortion after heat treatment.

By placing the dial gauge on the end face of a workpiece with a multi-stage shaft shape, it is also possible to measure the squareness of the end face with respect to both centers.

Principle of Eccentricity Measuring Instruments

1. Mechanical Measurement

Measurement of Center Standards
The centers of eccentricity measuring instruments are usually made of hardened steel. When used on hard workpieces or for frequent measurements, a carbide center with a carbide brazed tip may be used.

For workpieces with an inside diameter machined instead of a center hole at the edge of the workpiece, an umbrella type center is used. A center with the same bevel angle as the chamfer angle of the bore machining part is required.

A dial gauge is applied to the outer surface of the workpiece and the change in position of the workpiece outer surface is read while the workpiece is rotated slightly. This is the center-based eccentricity measurement.

Measurement of Outer Diameter Standard
Instead of clamping by both centers of eccentricity measuring instruments, the outer diameter of a workpiece is placed on two sets of rollers and supported by two sets of rollers at both ends of the workpiece, for a total of four rollers. Eccentricity can be measured by rotating the workpiece. The measurement value is based on the outside diameter.

There is also an eccentricity measuring instrument that can measure eccentricity by placing one side of the workpiece on a set of two rollers and attaching a roller for clamping to the top of the roller, thereby enabling single-handed measurement. For cylindrical shapes with inside diameter processing, where the coaxiality of the inside diameter with respect to the outside diameter is to be measured, a dial gage can be placed on the inside diameter and rotated to make the measurement.

In either case, the span of the two rollers must be adjusted according to the size of the workpiece diameter.

2. Principle of Non-contact Measurement

Laser Eccentricity Measuring Instrument
Runout of the outer diameter during rotation can be measured. Using a reflective laser displacement meter, a laser is shone on the outer surface of the rotating object and the reflected wave is detected to measure the distance variation. A sampling rate of at least 10 times the rotational speed is required.

Transmission-type laser dimensional measuring instruments can also be used for measurement. The laser is applied to the circumferential direction of the outer surface of the rotating body, and the p-p value of the runout is measured by the receiver. A sampling speed of at least 10 times the rotational speed is required.

In addition, using a transmission-type 2-D laser dimensional measuring instrument, positional variations at multiple points can be measured. Runout of V-grooves and protrusions cut on the circumference can be measured.

Optical Eccentricity Measuring Instrument
This method measures the eccentricity of convex and concave lenses. There are two types: reflective and transmissive. The reflective eccentricity measuring instrument measures the eccentricity between the outer diameter of the lens under test and the spherical center of the lens using the reflective method.

The transmission eccentricity measuring instrument measures the transmission eccentricity of a lens. Transmission eccentricity is the amount by which transmitted light deviates from the optical axis. The optical axis is the line connecting the spherical centers of both sides of the lens.

Other Information on Eccentricity Measuring Instruments

How to Use Eccentricity Measuring Instruments

First, on the table of the eccentricity measuring instrument, set the left and right centers at the desired positions according to the length of the workpiece and lock each of them. One of the left and right centers is designed to move in and out by operating a lever.

By operating this lever, the workpiece is set with the center retracted, and the workpiece is clamped by returning the lever. The force of the spring enables the workpiece to be supported with constant holding force.

The dial gauge is placed on the outer surface of the workpiece, and the workpiece is rotated. The change in the pointer obtained at that time is the eccentricity.

What Is a Low Resistance Measuring Instrument?

A low resistance measuring instrument is a device that can measure minute resistances in units of milliohms, which is less than 1 ohm.

General resistance measuring instruments cannot measure resistance of less than 1 ohm with high accuracy because they are affected by the contact resistance between the measuring instrument and the resistance and the wiring resistance of the measuring leads. A low resistance measuring instrument, on the other hand, is less affected by contact resistance and wiring resistance, and can measure resistances of less than 1 Ohm with high accuracy.

Uses of Low Resistance Measuring Instruments

Low resistance measuring instruments are used to measure the resistance of various samples. Specifically, they are used for measuring the winding resistance of motors, solenoids, and choke coils. They are also used to measure the contact resistance of wire harnesses, connectors, and switch contacts; and wiring resistance on printed circuit boards.

Low resistance measuring instrument should also be used to measure the resistance of current fuses and shunt resistors, and the DC resistance of conductive rubber.

Principle of Low Resistance Measuring Instruments

General resistance measuring instruments measure resistance using the 2-terminal method, while the measurement method used by the Low resistance measuring instrument to measure resistance is the 4-terminal method.

1. 2-Terminal Method

The two-terminal method uses a common lead wire for the current source and a common lead wire for the voltmeter. The current from the current source also flows through the voltmeter leads during resistance measurement, causing a voltage drop in the leads and in the contact resistance, resulting in a measurement error during resistance measurement.

2. 4-Terminal Method

The 4-terminal method uses the current source and voltmeter leads independently. Since no current flows in the voltage measurement leads and no voltage drop in the leads and contact resistance occurs, resistance can be measured with high accuracy.

Other Information on Low Resistance Measuring Instruments

1. Setting of Resistance Range

Set the resistance range of the low resistance measuring instrument according to the resistance value. There are two ways to set the resistance range: manual mode and auto mode. Use manual mode if you want to set the resistance range arbitrarily, and select auto mode if you want to set the resistance range automatically.

If you select auto mode, you have the advantage of not having to change the resistance range setting yourself. However, in the case of wire-wound resistance of motors, solenoids, choke coils, etc., the measured value may not be stable in the auto range. In such cases, it is better to set the resistance range manually and then measure the resistance value.

2. Setting of Measurement Current Range

Increasing the measurement current as much as possible increases the voltage at both ends of the resistor, which improves measurement accuracy. However, increasing the measurement current increases the current consumption of the resistor and causes the resistor to heat up.

As the resistor heats up, it is prone to problems such as resistance breakage, changes in resistance value, and magnetization of the resistor. These problems may result in incorrect resistance measurement. Conversely, if the measurement current is reduced, the voltage at both ends of the resistor becomes smaller, making it easier to be affected by external noise during measurement and making it more difficult to stabilize the measured value.

3. Setting the Measurement Speed

Slow down the measurement speed as much as possible, this will produce better measurement accuracy and the less the influence of extraneous noise. Faster measurement speeds shorten the measurement time, but are more susceptible to extraneous noise and make it more difficult to stabilize the measured value.

4. Method of Reducing External Noise

If the resistance measurement is affected by external noise, the measured value will not be stable and correct measurement will not be possible. Adequate shielding or twisting of lead wires can reduce the influence of external noise.

What Is a Mortar Adhesion Enhancer?

A mortar adhesion enhancer is an application agent that enhances the adhesion between the mortar and the construction surface to be bonded.

It can be used in conjunction with a quenching agent and is also known as an adhesion primer.

The bond strength of mortar adhesion enhancers is not proportional to the amount used, so it is important to use the proper dosage. When applied to the surface and allowed to dry before bonding cement or mortar, the adhesive bonds strongly to the coating, resulting in a high-strength repair.

Uses of Mortar Adhesion Enhancers

Mortar adhesion enhancers are used as pre-treatment for repairing damaged blocks or concrete to strengthen the adhesion to the work surface. After the surface is cleaned of dirt before bonding to the repaired area, the mortar adhesion enhancer is applied to the entire surface with a brush or roller and allowed to dry completely.

In addition to application to the substrate, the adhesive can also be mixed with cement to strengthen the adhesion. In either case, the undiluted solution of mortar adhesion enhancer should be diluted to the appropriate concentration.

Principle of Mortar Adhesion Enhancers

The main mortar adhesion enhancer is made from a special acrylic resin. When applied directly to old concrete construction surfaces with a brush, the liquid penetrates into the brittle layers for strong adhesion.

Adhesion can be improved by creating a new, finer surface. When applied to a highly water-absorbent surface, it forms a coating film to reduce water absorption on the surface. When applied in several layers on a highly water-absorbing surface, a highly effective result can be obtained.

Types of Mortar Adhesion Enhancers

Mortar adhesion enhancers generally include ethylene-vinyl acetate and acrylic resins.

Ethylene-vinyl acetate is also called ethylene-vinyl acetate, abbreviated as EVA. Vinyl acetate has adhesive strength and is a raw material used in woodworking bonds. Mixed with ethylene as the main raw material, polyethylene has excellent flexibility, water resistance, and alkali resistance. It is an excellent mortar adhesion enhancer and is often used in plastering and mortar work.

Acrylic resins are mainly composed of methacrylic ester, acrylic ester, and styrene. Among synthetic resin emulsions, they have very high transparency and weather resistance. They can form a solid film even with common paints and are excellent at controlling pinholes. It can also be used as a primer and sealer for self-leveling materials such as cement and plaster.

How to Select a Mortar Adhesion Enhancer

A wide variety of material is used in the formulation of mortar, one of which is an adhesion enhancer. This is an application material that strengthens the adhesion between the mortar and the substrate, and is easily effective when applied directly to the construction surface by roller or brush. It is bonded to the substrate with a special acrylic resin that forms small bumps on the surface, which can be adhered by the mortar. In order to apply the mortar adhesion enhancer to the area to be mortared, it is necessary to brush off any dirt from the installation area beforehand.

Mortar admixture improves the glide of the trowel when applying mortar and provides a smooth finish. Mixing it into the mortar when making the mortar reduces cracking, and it also prevents cracking when applied thickly.

Colored powders can be easily mixed into mortar to create beautiful colors. Generally, even 1% of the amount of cement is sufficient to produce sufficient color, so care should be taken with the amount of mixture. A blending amount of 8% will produce the color of colored powder.

Structure of Mortar Adhesion Enhancer

Mortar consists of three raw materials: fine aggregate, cement, and water. Sand used for fine aggregate is small grains with a diameter of 5 mm or less, which make the trowel finish smooth when the three raw materials are mixed. Cement is made by baking and grinding clay or limestone and is a grayish-white powdery material. It hardens when water is added and is utilized in all areas of construction sites.

The ratio of fine aggregate: cement: water should be 6:2:1 by weight. When using a small amount of mortar, it can be measured with a lightweight cup and the same ratio can be used. Mixing the mortar according to the formula will yield the same amount of mortar as sand.

What Is Photocatalytic Paint?

Photocatalytic paints are paints made from titanium dioxide or titanium dioxide.

They are typically used to paint the exterior walls of buildings. Exposure to light or ultraviolet rays after application exerts a self-cleaning effect.

Uses of Photocatalytic Paints

Because of its self-cleaning effect, photocatalytic paint is often used to paint exterior walls that are particularly difficult to maintain on a regular basis.

Fluoropolymer paints, which are high-grade paints, have a durability of 15 to 20 years, and photocatalytic paints have the same durability. Therefore, it is sometimes used for high-rise buildings where the number of maintenance cycles needs to be kept low. Because it is a high-quality paint, the initial investment is high, but the advantage is that running costs can be kept down.

Principle of Photocatalytic Paints

The main raw materials for photocatalytic paints are titanium dioxide and titanium dioxide. After photocatalytic paint is applied, exposure to light or ultraviolet light causes a separation of electrons and holes (excited state) within the titanium dioxide or titanium dioxide contained in the paint. Because electrons are ejected from the photocatalytic paint, the surface of the photocatalytic paint is positively charged.

This positively charged surface has a very strong oxidizing power and decomposes water adhering to the photocatalytic paint surface to produce hydroxyl radicals. These hydroxyl radicals are extremely unstable substances. Therefore, they combine with organic compounds, organic chemicals, exhaust gases, and other pollutants that are the source of dirt on the wall surface, decompose them, and provide a self-cleaning effect that prevents the adhesion of dirt.

On the other hand, the electrons emitted from photocatalytic paint undergo a reduction reaction with oxygen to produce a superoxide anion. This superoxide anion is also a substance with very strong oxidizing power. It binds to organic compounds, organic chemicals, exhaust gases, and other pollutants, decomposing them and preventing the adhesion of dirt, thereby achieving a self-cleaning effect.

In addition, photocatalytic paint is characterized by its highly hydrophilic surface. Therefore, even if rain or other water adheres to a wall surface coated with photocatalytic paint, it will not form water droplets, but will instead run off. The above-mentioned decomposed organic compounds, organic chemicals, dust, and other substances are washed away with the rain, providing a self-cleaning effect. Titanium dioxide and titanium dioxide are safe substances, and photocatalytic paints are environmentally friendly.

Other Information on Photocatalytic Paints

1. Ultraviolet Photocatalytic Paint and Visible Light Photocatalytic Paint

There are two types of photocatalytic paints: ultraviolet photocatalytic paints, which provide self-cleaning effects with ultraviolet light, and visible photocatalytic paints, which provide self-cleaning effects with visible light. Conventionally, ultraviolet photocatalytic paints have been widely used. However, UV photocatalytic paints have the disadvantage that the self-cleaning effect cannot be obtained without UV light.

Visible light photocatalytic paints are effective not only with ultraviolet light but also with visible light, and their functionality is superior to that of ultraviolet light photocatalytic paints. Therefore, the visible light type is generally selected unless it is used for special applications.

2. Photocatalytic Paint for Interior Applications

In recent years, photocatalytic paints for interior use have also become available. When photocatalytic paints are used for interiors, the same self-cleaning effect can be achieved as with photocatalytic paints for exterior walls. As a result, it has antifouling, antibacterial, and antiviral effects, and can also decompose odor substances.

It can control bothersome odors from pets and garbage, and clean the air. It also prevents the formation of mold and is suitable for places where water is frequently used.

3. Price of Photocatalytic Paint

Photocatalytic paint is usually applied by a specialized contractor because the application process is finely divided and requires expertise. For example, the cost of painting an exterior wall is said to be “15 – 25 USD” per square meter.

Silicon paint, which is often used for exterior walls and costs approximately “15 – 25 USD” per m2, and fluorine paint, which is considered somewhat more expensive, costs about “25 – 35 USD” per m2. The initial cost tends to be higher when painting with photocatalytic paint.

It is important to make a comprehensive decision, taking into consideration the service life and effectiveness, whether for exterior wall painting or interior decoration.

What Is a Photocatalytic Coating Agent?

Photocatalytic coating agents are coatings applied to building exteriors and interiors that have antifouling properties to prevent these stains.

The antifouling effect is achieved by taking advantage of the properties of photocatalysts.

Uses of Photocatalytic Coating Agents

Photocatalytic coating agents are used to coat building exterior walls, interior wallpaper, and curtains that are exposed to ultraviolet light from the sun or fluorescent lamps. Photocatalytic coating agents are characterized by their high hydrophilicity and positive charge. They decompose organic matter such as pollutants, viruses, and odorants contained in water, and provide antifouling and cleaning effects.

Therefore, the antifouling effect makes it possible to maintain cleanliness. When used on building walls, when rainwater adheres to the wall surface, the rainwater spreads along the coating film, and the pollutants in the rainwater and organic matter such as dirt adhering to the wall surface are decomposed by the oxidation-reduction reaction with the photocatalyst and washed away with the rainwater.

In addition, photocatalytic coating agents do not damage fibers and can be used on fabric products such as curtains and sofas, thus reducing material deterioration and preserving the beauty of the product. Furthermore, since it decomposes organic substances, such as viruses, odor components, and dirt, it also has the deodorizing and antibacterial effects required for these products used indoors.

Principle of Photocatalytic Coating Agents

Photocatalysts, such as titanium dioxide (often called titanium dioxide) used in photocatalytic coating agents, are highly hydrophilic and positively charged when they absorb UV light.

When moisture adheres to the film created by the photocatalytic coating agent, it spreads along the film due to its high hydrophilicity. At this time, the organic matter contained in the water is decomposed by the redox reaction of the positively charged photocatalyst.

Photocatalytic coating agents are very sustainable coatings, considering the fact that the effect can be achieved repeatedly as long as the photocatalyst is exposed to light, air, and water, and that the effect is achieved without the use of energy such as electricity, and that no waste products are generated.

Other Information on Photocatalytic Coating Agents

1. Advantages and Disadvantages of Photocatalytic Coating Agents

Advantages
These include antibacterial, antiviral, and deodorizing effects when used for interior applications. Another advantage is that once used, the effects are long-lasting and require little or no maintenance.

Furthermore, there are virtually no health problems. The main ingredient of photocatalytic coating agents is titanium dioxide, which has almost no effect on the human body even if ingested orally. Another advantage is that commercially available products meet safety standards for various items, including acute toxicity tests, skin irritation tests, and mutagenicity tests for oral intake.

Disadvantages
One disadvantage related to photocatalytic coating agents is that they tend to be more expensive. This is because photocatalytic coating agents themselves are more expensive than other coating agents, resulting in higher initial costs at the time of installation.

Also, when used on walls and other surfaces, antibacterial, antiviral, and deodorizing effects can be expected on the coated surface, but little effect can be expected on substances suspended in the air. Another disadvantage is that there are various types of bacteria and viruses, so antimicrobial and antiviral effects against all types of bacteria and viruses cannot be guaranteed.

2. Photocatalytic Coating Agent Price

There are various quantities and types of photocatalytic coating agents on the market. Prices vary, with most products available for hundreds to thousands of dollars. Spray-type products have smaller volumes and are relatively inexpensive, while paint-type products for interior walls have larger volumes and are more expensive.

If photocatalytic coating agents are to be applied to the entire interior, a request must be made to a specialized contractor. In this case, the unit price per square meter of coating is several thousand yen, but it varies slightly depending on conditions, such as the location to be coated. Photocatalytic coating agents are more expensive than other paints, so the initial cost tends to be higher, and a comprehensive decision must be made based on factors such as service life and effectiveness.

What Is a Low Temperature Incubator?

A low temperature incubator is a device that can control the inside of a chamber at a constant low temperature. It is also called a low-temperature incubator, a low-temperature tester, or a low-temperature incubator. The temperature that can be controlled varies slightly depending on the product, but it can be set between -15°C and 60°C.

Low temperature incubators with programmable functions can incorporate multiple patterns of time and temperature control. They are used in a wide range of fields for operations and processes that require temperature control, and are used for quality control, experimentation, and testing, in addition to culture and storage.

Figure 1. Overview image of the cryogenic incubator

Uses of Low Temperature Incubators

Low temperature incubators are used in many fields, including institutions that handle electronic components, food, precision instruments, and living organisms.

They are used when a constant low-temperature environment is required. Specific uses of low-temperature incubators include tests and experiments at low or constant temperatures, such as plant germination experiments and environmental tests, storage of parts requiring precision control such as electronic equipment, and culture and storage of bacteria and microbes in the physiological field.

In the food field, it is used for strict preservation tests related to HACCP food hygiene management methods and ISO 22000 certification. It is also used for long-term continuous stability testing of pharmaceuticals and cosmetics.

Principle of Low Temperature Incubators

There are two main methods by which low temperature incubators maintain a constant temperature inside the tank. One is the “air circulation method,” which circulates air inside the tank, and the other is the “air jacket method,” which controls the temperature by air flow created from outside the layers by means of a jacket.

• Air Circulation System
  In the air circulation method, a fan mounted inside the chamber rotates to stir the air inside the chamber and send airflow to keep the temperature inside the chamber uniform.
• Air Jacket System
  The air jacket system controls temperature from the outside without creating airflow inside the cabinet. In addition, by periodically changing the direction of the refrigerant, frost formation is prevented due to prolonged operation, allowing for uninterrupted, continuous use.

Cooling systems include those using hydrofluorocarbon (HFC) refrigerants, as well as those using Peltier elements. Although frost tends to form on the cooler during long-term use, some products utilize inverter control to improve frost formation and reduce the need for periodic defrosting (defrosting with hot gas).

Figure 2. Front view of air jacket system / Figure3. Side view of air circulation system

Types of Low Temperature Incubators

The applications for low temperature incubators are very diverse, but it is important to select the right one for your application, as the detailed specifications vary from product to product. The following are examples of points to check when selecting a product.

1. Temperature Range

There are several temperature ranges alone, such as -10~+50°C, 0~60°C, -20~+85°C, and so on. For example, when conducting food preservation tests, it is necessary to select products for room temperature (10 to 35°C), refrigeration (0 to 10°C), and freezing (-15°C or lower). Also, it should be noted that the accuracy of temperature distribution varies from product to product, ranging from ±0.3°C to ±2°C.

2. Size

They come in a variety of sizes, from tabletop models to floor models. Choose a low-vibration product if vibration is a concern, or a product with a full range of program functions if you want to set detailed operation programs.

3. Safety-Enhancing Features

If safety is important, choose a product with an automatic overload protection function, an overload protection device, or an overcurrent leakage breaker.

For long-term continuous testing, it is safer to choose a product that is manufactured to operate for long periods of time. Some products are equipped with two independent refrigeration circuits in case of trouble. If high-precision testing is required, the accuracy of calibration at the time of installation should also be taken into consideration.

What Is an Extrusion Double Corner Brace?

An extrusion double corner brace is an earthquake-resistant reinforcement device in which a viscoelastic material of polymeric material is sandwiched between steel plates.

The joints between columns and beams are called “joints,” and they are fan-shaped, divided into four circles. When attached to beam joints or columns, the device absorbs loads on wooden buildings caused by strong winds or earthquakes and suppresses deformation.

Compared to conventional construction methods such as load-bearing walls and bonding hardware, it has superior earthquake resistance effects. Lightweight and compact, it can be installed in space-saving locations such as behind ceilings, and is easy to install. No maintenance is required and can be reinforced in combination with conventional construction methods.

Uses of Extrusion Double Corner Braces

Regardless of whether new construction or renovation, extrusion double corner braces are used in a wide range of applications, from private residences to temples and shrines, as long as conventional wooden frame construction methods are used.

Since they can immediately suppress deformation and swaying of buildings in the event of strong winds and earthquakes, their installation significantly improves earthquake resistance performance. For a normal house, the standard number of damper units installed is one per 3.3 square meters, and installation costs are low.

Different types can be used depending on the type of housing. The 15 cm type is used for ordinary wooden houses, the 20 cm type for new houses, and the 30 cm type for shrine and temple buildings.

Principle of Extrusion Double Corner Braces

Vibration suppression dampers can be installed in places where buildings are severely deformed during earthquakes and strong winds. Since building deformation occurs when columns and beams expand, contract, or bend, installing gatekeeper dampers at the ends of these areas can be effective. Vibration-control dampers installed at the ends of the building are called extrusion double corner braces, and can actually be installed in such a way as to connect the sections of the columns and beams that are close to the ends.

The construction time for gatekeeper dampers is short, and they can be installed in one day in a typical house. Once installed, they require no daily maintenance, and tests have shown that they can last for more than 50 years.

The reinforcement plan can also be studied in an easy way, assuming a wall volume of 25 cm per 15 cm type. We also have analytical and design methods in place to evaluate the effectiveness of seismic reinforcement quantitatively, allowing us to study the amount of reinforcement to meet your needs.

Types of Extrusion Double Corner Braces

Extrusion double corner braces are viscoelastic dampers made of polymeric materials. Viscoelastic materials such as styrene, silicone, and acrylic are used as polymer materials.

Each unit weighs less than 2 kg, making it lightweight and compact. They are so easy to install that they can be installed in space-saving locations such as under ceilings, attics, and floors, and can be easily installed using special wood screws.

The design has a high degree of freedom, and the traditional Japanese color black is often used to match Japanese-style architecture, with a matte finish. It blends in with the color change of wood over time and the old coloring of pillars and beams, and can be installed in places where it is out of sight without being noticed.

How to Choose an Extrusion Double Corner Braces

In most wooden houses, the pillars only support the weight of the building, and the walls, called bearing walls, which resist earthquakes. Because of the difficulty of joining posts, beams, and other timbers, this cannot be accomplished in wood construction without special construction methods, but an extrusion double corner brace can be installed to absorb energy.

Unlike wooden houses, joints are difficult in steel-frame and reinforced concrete construction. Although there are extrusion double corner braces for steel construction, the joints can be freely rotated to install the gatekeeper damper, and it is necessary to change the part that can originally bear the force so that it cannot. Therefore, it is not very reasonable.

Structure of Extrusion Double Corner Braces

The structure of an extrusion double corner brace consists of a viscoelastic body sandwiched between steel plates. Control is required in each manufacturing process of the viscoelastic body, steel plate, and finished product. In order to ensure the performance to be achieved, it is important to establish a system that can provide stable products by defining control items in each manufacturing process.

An extrusion double corner brace can be attached to the partitions of columns and beams to give a certain strength to a building and absorb the energy of shaking in an earthquake. Thus, it helps to reduce deformation and sway.

What Is a Round Nut?

A round nut is a nut with a cylindrical shape.

It is usually made of metal and is characterized by its cylindrical appearance compared to the common hexagonal nut. It has an axial hole in the center, into which a screw or bolt is inserted, and the screw or bolt is tightened by turning the nut. Because of its cylindrical shape, it is considered more difficult to loosen than a hexagonal nut. This is because the joint of the nut helps distribute the force evenly.

Round nuts are sometimes chosen because stable fastening is required, especially when used in environments subject to vibration or shock. They also have a cylindrical shape and are considered beautiful in appearance. Therefore, they are sometimes used where decorative elements are required.

Round nuts are often used in the assembly of furniture and buildings. Due to their round shape, they are easy to grip and loosen by hand. They are useful for maintenance and repair work.

Uses of Round Nuts

Round nuts are used in a variety of industries and fields because of their beautiful appearance and hard-to-disassemble structure.

1. Furniture

Round nuts are used to fasten or assemble parts. Round nuts may be used especially in wooden and metal furniture.

2. Interior Art Works

Because of its decorative element, round nuts are sometimes used in interior design, artwork, and other situations where aesthetic elements are desired.

3. Automobiles

Round nuts are also used in the assembly and maintenance of automobiles. They are sometimes used to install engine parts, suspension, and other components. Round nuts are stable and do not easily come off, thus improving the safety of the vehicle.

Round nuts for welding are used on thin steel plates when it is difficult to tighten parts by threading. The nuts are pre-fitted by spot welding or other means.

Cross-inserted round nuts can be installed in cases where the connection is structurally difficult or the material is weak.

Principle of Round Nuts

Round nuts are used to fasten parts together and are used with bolts and screws. The round nut tightens the screw or bolt, generating a fastening force. Turning the nut causes the screw or bolt to move axially against the nut, increasing the contact area. This increases the frictional force and tightens the screw or bolt.

Frictional force is an important factor that prevents the screw or bolt from coming off. Round nuts have a cylindrical shape and are characterized by their ability to distribute force evenly. This ensures that the fastening force is evenly distributed around the screw or bolt, enabling stable fastening.

However, proper knowledge is required for fastening operations and usage. For safe use, it is important to observe proper torque and fastening procedures.

Types of Round Nuts

Various types of round nuts exist. It is important to select the appropriate size and material of round nut depending on the usage and requirements. The following are examples of round nut types.

1. General Round Nut

This is a round nut of general shape. It has a cylindrical appearance and a shaft hole in the center. It is used for fastening through screws or bolts.

2. Round Nut With a Flange

This round nut has a flange on the bottom of the cylindrical nut. The flange extends across the surface of the member to be fastened, providing a larger contact area and greater stability. It is also characterized by its resistance to vibration and impact. Because of this feature, it is also used for automobile engine parts.

3. Round Nut With a Horizontal Hole

This round nut has a cylindrical shape but has lateral holes on its side. The lateral holes allow for additional fastening of screws or bolts. By passing a pin or wire through the transverse hole, the screw or bolt can be prevented from loosening or rotating. This improves fastening stability.

Horizontal hole round nuts are sometimes used in automotive sports equipment such as motorcycles and bicycles. They are also widely used in furniture.