National Diet Library
The National Diet Library is the national library of Japan and among the largest libraries in the world. It was established in 1948 for the purpose of assisting members of the National Diet of Japan in researching matters of public policy; the library is similar in scope to the United States Library of Congress. The National Diet Library consists of two main facilities in Tōkyō and Kyōtō, several other branch libraries throughout Japan; the National Diet Library is the successor of three separate libraries: the library of the House of Peers, the library of the House of Representatives, both of which were established at the creation of Japan's Imperial Diet in 1890. The Diet's power in prewar Japan was limited, its need for information was "correspondingly small"; the original Diet libraries "never developed either the collections or the services which might have made them vital adjuncts of genuinely responsible legislative activity". Until Japan's defeat, the executive had controlled all political documents, depriving the people and the Diet of access to vital information.
The U. S. occupation forces under General Douglas MacArthur deemed reform of the Diet library system to be an important part of the democratization of Japan after its defeat in World War II. In 1946, each house of the Diet formed its own National Diet Library Standing Committee. Hani Gorō, a Marxist historian, imprisoned during the war for thought crimes and had been elected to the House of Councillors after the war, spearheaded the reform efforts. Hani envisioned the new body as "both a'citadel of popular sovereignty'", the means of realizing a "peaceful revolution"; the Occupation officers responsible for overseeing library reforms reported that, although the Occupation was a catalyst for change, local initiative pre-existed the Occupation, the successful reforms were due to dedicated Japanese like Hani. The National Diet Library opened in June 1948 in the present-day State Guest-House with an initial collection of 100,000 volumes; the first Librarian of the Diet Library was the politician Tokujirō Kanamori.
The philosopher Masakazu Nakai served as the first Vice Librarian. In 1949, the NDL became the only national library in Japan. At this time the collection gained an additional million volumes housed in the former National Library in Ueno. In 1961, the NDL opened at its present location in Nagatachō, adjacent to the National Diet. In 1986, the NDL's Annex was completed to accommodate a combined total of 12 million books and periodicals; the Kansai-kan, which opened in October 2002 in the Kansai Science City, has a collection of 6 million items. In May 2002, the NDL opened a new branch, the International Library of Children's Literature, in the former building of the Imperial Library in Ueno; this branch contains some 400,000 items of children's literature from around the world. Though the NDL's original mandate was to be a research library for the National Diet, the general public is the largest consumer of the library's services. In the fiscal year ending March 2004, for example, the library reported more than 250,000 reference inquiries.
As Japan's national library, the NDL collects copies of all publications published in Japan. Moreover, because the NDL serves as a research library for Diet members, their staffs, the general public, it maintains an extensive collection of materials published in foreign languages on a wide range of topics; the NDL has eight major specialized collections: Modern Political and Constitutional History. The Modern Political and Constitutional History Collection comprises some 300,000 items related to Japan's political and legal modernization in the 19th century, including the original document archives of important Japanese statesmen from the latter half of the 19th century and the early 20th century like Itō Hirobumi, Iwakura Tomomi, Sanjō Sanetomi, Mutsu Munemitsu, Terauchi Masatake, other influential figures from the Meiji and Taishō periods; the NDL has an extensive microform collection of some 30 million pages of documents relating to the Occupation of Japan after World War II. This collection include the documents prepared by General Headquarters and the Supreme Commander of the Allied Powers, the Far Eastern Commission, the United States Strategic Bombing Survey Team.
The Laws and Preliminary Records Collection consists of some 170,000 Japanese and 200,000 foreign-language documents concerning proceedings of the National Diet and the legislatures of some 70 foreign countries, the official gazettes, judicial opinions, international treaties pertaining to some 150 foreign countries. The NDL maintains a collection of some 530,000 books and booklets and 2 million microform titles relating to the sciences; these materials include, among other things, foreign doctoral dissertations in the sciences, the proceedings and reports of academic societies, catalogues of technical standards, etc. The NDL has a collection of 440,000 maps of Japan and other countries, including the topographica
A gun barrel is a crucial part of gun-type ranged weapons such as small firearms, artillery pieces and air guns. It is the straight shooting tube made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas is introduced behind a projectile in order to propel it out of the front end at a high velocity; the hollow interior of the barrel is called the bore. The measurement of the diameter of the bore is called the caliber. Caliber is measured in inches or millimetres; the first firearms were made at a time when metallurgy was not advanced enough to cast tubes capable of withstanding the explosive forces of early cannons, so the pipe needed to be braced periodically along its length for reinforcement, producing an appearance somewhat reminiscent of storage barrels being stacked together, hence the English name. Gun barrels are metal. However, the early Chinese, the inventors of gunpowder, used bamboo, which has a strong tubular stalk and is cheaper to obtain and process, as the first barrels in gunpowder projectile weapons such as the fire lances.
The Chinese were the first to master cast-iron cannon barrels, used the technology to make the earliest infantry firearms — the hand cannons. Early European guns were made of wrought iron with several strengthening bands of the metal wrapped around circular wrought iron rings and welded into a hollow cylinder. Bronze and brass were favoured by gunsmiths because of their ease of casting and their resistance to the corrosive effects of the combustion of gunpowder or salt water when used on naval vessels. Early firearms were muzzle-loading, with the gunpowder and the shot loaded from the front end of the barrel, were capable of only a low rate of fire due to the cumbersome loading process; the later-invented breech-loading designs provided a higher rate of fire, but early breechloaders lacked an effective way of sealing the escaping gases that leaked from the back end of the barrel, reducing the available muzzle velocity. During the 19th century, effective breechblocks were invented that sealed a breechloader against the escape of propellant gases.
Early cannon barrels were thick for their caliber. This was because manufacturing defects such as air bubbles trapped in the metal were common back in the days, played key factors in many gun explosions. A gun barrel must be able to hold in the expanding gas produced by the propellants to ensure that optimum muzzle velocity is attained by the projectile as it is being pushed out. If the barrel material cannot cope with the pressure within the bore, the barrel itself might suffer catastrophic failure and explode, which will not only destroy the gun but present a life-threatening danger to people nearby. Modern small arms barrels are made of carbon steel or stainless steel materials known and tested to withstand the pressures involved. Artillery pieces are made by various techniques providing reliably sufficient strength. In firearms terminology, fluting refers to the removal of material from a cylindrical surface creating rounded grooves, for the purpose of reducing weight; this is most done to the exterior surface of a rifle barrel, though it may be applied to the cylinder of a revolver or the bolt of a bolt-action rifle.
Most flutings on rifle barrels and revolver cylinders are straight, though helical flutings can be seen on rifle bolts and also rifle barrels. While the main purpose of fluting is just to reduce weight and improve portability, when adequately done it can retain the structural strength and rigidity and increase the overall specific strength. Fluting will increase the surface-to-volume ratio and make the barrel more efficient to cool after firing, though the reduced material mass means the barrel will heat up during firing; the chamber is the cavity at the back end of a breech-loading gun's barrel where the cartridge is inserted in position ready to be fired. In most firearms, the chamber is an integral part of the barrel made by reaming the rear bore of a barrel blank, with a single chamber within a single barrel. In revolvers, the chamber is a component of the gun's cylinder and separate from the barrel, with a single cylinder having multiple chambers that are rotated in turns into alignment with the barrel in anticipation of being fired.
Structurally, the chamber consists of the body and neck, the contour of which correspond to the casing shape of the cartridge it is designed to hold. The rear opening of the chamber is the breech of the whole barrel, sealed tight from behind by the bolt, making the front direction the path of least resistance during firing; when the cartridge's primer is struck by the firing pin, the propellant is ignited and deflagrates, generating high-pressure gas expansion within the cartridge case. However, the chamber restrains the cartridge case from moving, allowing the bullet to separate cleanly from the casing and be propelled forward along the barrel to exit out of the front end as a projectile; the act of chambering a gun refers to the process of loading a cartridge into the gun's chamber, either manually as in single loading, or via operating the weapon's own action as in pump action, lever action, bolt action or self-loading actions. In the case of an air gun, a pellet itself has no casing to be retained and will be inserted into the chamber (often called "seating
A tipped tool is any cutting tool in which the cutting edge consists of a separate piece of material, brazed, welded, or clamped onto a body made of another material. In the types in which the cutter portion is an indexable part clamped by a screw, the cutters are called inserts. Tipped tools allow each part of the tool, the shank and the cutter, to be made of the material with the best properties for its job. Common materials for the cutters include cemented carbide, polycrystalline diamond, cubic boron nitride. Tools that are tipped include milling cutters, tool bits, router bits, saw blades; the advantage of tipped tools is only a small insert of the cutting material is needed to provide the cutting ability. The small size makes manufacturing of the insert easier than making a solid tool of the same material; this reduces cost because the tool holder can be made of a less-expensive and tougher material. In some situations a tipped tool is better than its solid counterpart because it combines the toughness of the tool holder with the hardness of the insert.
In other situations this is less than optimal, because the joint between the tool holder and the insert reduces rigidity. However, these tools may still be used. In industry today, insert tools are slightly more common than solid tools, but solid tools are still used in many applications. Entire catalogs of solid–high-speed steel and solid-carbide end mills, for example, play prominent parts in some areas of milling practice, including diesinking and aerospace job or batch production. Most machine shops with lathes have many solid-HSS and solid-carbide tool bits as well as many insert-tipped tool bits, most commercial operations that involve routers use plenty of solid-HSS and solid-carbide router bits as well as some tipped bits. Inserts are removable cutting tips, which means they are not welded to the tool body, they are indexable, meaning that they can be exchanged, also rotated or flipped, without disturbing the overall geometry of the tool. This saves time in manufacturing by allowing fresh cutting edges to be presented periodically without the need for tool grinding, setup changes, or entering of new values into a CNC program.
A wiper insert is an insert used in a lathe. It is designed for finished cutting, it uses special geometry to give a good finish on the workpiece at a higher-than-normal feedrate. Wiper inserts have a larger area in contact with the workpiece, so they exert higher force on the workpiece; this makes them unsuitable for fragile workpieces. Inserts used for turning and milling are numbered according to ISO standard 1832; this standard aims to make the naming and ordering of inserts a simple and traceable process. This standard takes into account both metric and imperial systems of units, although certain elements differ for each unit system; the code consists of up to 13 symbols with the first 12 of them being compulsory for inserts composed of cubic boron or poly-crystalline diamond and the first 7 being compulsory for all other types of composition. Diamond tools Diamond blade
A boring bar is a tool used in metalworking and woodworking. Boring is a technique used in many aspects of building. Woodworkers have used boring as a form of drilling for centuries. In woodworking, the boring tool is used to form circular plunge cuts. In metalworking, boring is different in that the hole that results need not be circular. In metal boring the tool can be plunged and dragged on the X or Y axes to create a slot or asymmetrical hole or channel, or it may be moved only in an up-and-down motion to create a perfect circular hole. Modern boring tools have three primary components although many differing designs; the parts include bar holder and dial screw. The body, made of solid stock, has two basic parts; the top part threads or presses into the supporting shank. The lower part is connected via dovetail, T-slots or a smooth notch with an adjustment for bore diameter via the dial screw; as the dial screw is adjusted, the cutting bit/s are moved further out. This can create some slight distortion if the cutting tool is moved further than the boring head is designed to support, if there is undue wear in the bearings supporting the tool or if the tool speed is too great for the off-balance effect caused by moving the tool too far from center.
This is called unbalanced gyroscope precession. Once the dial screw has been adjusted to give the proper cut a set screw is used to prevent any additional movement of the cutting head; the third basic part is the boring tool. Boring tools can be mounted horizontally in many boring head designs. Boring can be done on mills, lathes or drill press machines, either with a boring head or with just a boring tool; the shorter the distance between the tool holder and the material, the less distortion created from vibration or unbalanced gyroscopic effects. The greater the distance the more flex in the tool or an increase in the imbalance of a moving tool. Use of a boring head decreases the distance. If a vibration is created it will be at a higher frequency and the deflection of the tool from the desired path will be much smaller and easier to erase through repetitive tool passes. In the case of a dynamic tool, the balance of the tool can be adjusted with counterweights if the tool is mounted perpendicular to the shaft or the tool length can be decreased
Turning is a machining process in which a cutting tool a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates. The term "turning" is reserved for the generation of external surfaces by this cutting action, whereas this same essential cutting action when applied to internal surfaces is called "boring", thus the phrase "turning and boring" categorizes the larger family of processes known as lathing. The cutting of faces on the workpiece, whether with a turning or boring tool, is called "facing", may be lumped into either category as a subset. Turning can be done manually, in a traditional form of lathe, which requires continuous supervision by the operator, or by using an automated lathe which does not. Today the most common type of such automation is computer numerical control, better known as CNC; when turning, the workpiece is rotated and a cutting tool is traversed along 1, 2, or 3 axes of motion to produce precise diameters and depths.
Turning can be either on the outside of the cylinder or on the inside to produce tubular components to various geometries. Although now quite rare, early lathes could be used to produce complex geometric figures the platonic solids; the turning processes are carried out on a lathe, considered to be the oldest machine tools, can be of four different types such as straight turning, taper turning, profiling or external grooving. Those types of turning processes can produce various shapes of materials such as straight, curved, or grooved workpiece. In general, turning uses simple single-point cutting tools; each group of workpiece materials has an optimum set of tools angles which have been developed through the years. The bits of waste metal from turning operations are known as swarf. In some areas they may be known as turnings; the tool's axes of movement may be a straight line, or they may be along some set of curves or angles, but they are linear. Turning specific operations include: Turning The general process of turning involves rotating a part while a single-point cutting tool is moved parallel to the axis of rotation.
Turning can be done on the external surface of the part as well as the internal surface. The starting material is a workpiece generated by other processes such as casting, extrusion, or drawing. Tapered turning Tapered turning produces a cylindrical shape that decreases in diameter from one end to the other; this can be achieved a) from the compound slide b) from taper turning attachment c) using a hydraulic copy attachment d) using a C. N. C. Lathe e) using a form tool f) by the offsetting of the tailstock - this method more suited for shallow tapers. Spherical generation Spherical generation produces a spherical finished surface by turning a form around a fixed axis of revolution. Methods include a) using hydraulic copy attachment b) C. N. C. Lathe c) using a form tool d) using bed jig. Hard turning Hard turning is a type of turning done on materials with a Rockwell C hardness greater than 45, it is performed after the workpiece is heat treated. The process is intended to limit traditional grinding operations.
Hard turning, when applied for purely stock removal purposes, competes favorably with rough grinding. However, when it is applied for finishing where form and dimension are critical, grinding is superior. Grinding produces higher dimensional accuracy of roundness and cylindricity. In addition, polished surface finishes of Rz=0.3-0.8z cannot be achieved with hard turning alone. Hard turning is appropriate for parts requiring a roundness accuracy of 0.5-12 micrometres, and/or surface roughness of Rz 0.8–7.0 micrometres. It is used for gears, injection pump components, hydraulic components, among other applications. Facing Facing in the context of turning work involves moving the cutting tool at right angles to the axis of rotation of the rotating workpiece; this can be performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed. It is the first operation performed in the production of the workpiece, the last—hence the phrase "ending up". PartingThis process called parting off or cutoff, is used to create deep grooves which will remove a completed or part-complete component from its parent stock.
Grooving Grooving is like parting, except that grooves are cut to a specific depth instead of severing a completed/part-complete component from the stock. Grooving can be performed on external surfaces, as well as on the face of the part. Non-specific operations include: Boring Enlarging or smoothing an existing hole created by drilling, moulding etc.i.e. The machining of internal cylindrical forms a) by mounting workpiece to the spindle via a chuck or faceplate b) by mounting workpiece onto the cross slide and placing cutting tool into the chuck; this work is suitable for castings. On long bed lathes large workpiece can be bolted to a fixture on the bed and a shaft passed between two lugs on the workpiece and these lugs can be bored out to size. A limited application b
A lathe is a machine that rotates a workpiece about an axis of rotation to perform various operations such as cutting, knurling, deformation and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis. Lathes are used in woodturning, metal spinning, thermal spraying, parts reclamation, glass-working. Lathes can be used to shape the best-known design being the Potter's wheel. Most suitably equipped metalworking lathes can be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity; the workpiece is held in place by either one or two centers, at least one of which can be moved horizontally to accommodate varying workpiece lengths. Other work-holding methods include clamping the work about the axis of rotation using a chuck or collet, or to a faceplate, using clamps or dogs. Examples of objects that can be produced on a lathe include screws, gun barrels, cue sticks, table legs, baseball bats, musical instruments and much more.
The lathe is an ancient tool, with tenuous evidence for its existence at a Mycenaean Greek site, dating back as far as the 13th or 14th century BC. Clear evidence of turned artifacts have been found from the 6th century BC: fragments of a wooden bowl in an Etruscan tomb in Northern Italy as well as two flat wooden dishes with decorative turned rims from modern Turkey. During the Warring States period in China, ca 400 BCE, the ancient Chinese used rotary lathes to sharpen tools and weapons on an industrial scale; the first known painting showing a lathe dates to the 3rd century BC in ancient Egypt. The lathe was important to the Industrial Revolution, it is known as the mother of machine tools, as it was the first machine tool that led to the invention of other machine tools. The first documented, all-metal slide rest lathe was invented by Jacques de Vaucanson around 1751, it was described in the Encyclopédie. An important early lathe in the UK was the horizontal boring machine, installed in 1772 in the Royal Arsenal in Woolwich.
It was horse-powered and allowed for the production of much more accurate and stronger cannon used with success in the American Revolutionary War in the late 18th century. One of the key characteristics of this machine was that the workpiece was turning as opposed to the tool, making it technically a lathe. Henry Maudslay who developed many improvements to the lathe worked at the Royal Arsenal from 1783 being exposed to this machine in the Verbruggen workshop. A detailed description of Vaucanson's lathe was published decades before Maudslay perfected his version, it is that Maudslay was not aware of Vaucanson's work, since his first versions of the slide rest had many errors that were not present in the Vaucanson lathe. During the Industrial Revolution, mechanized power generated by water wheels or steam engines was transmitted to the lathe via line shafting, allowing faster and easier work. Metalworking lathes evolved into heavier machines with more rigid parts. Between the late 19th and mid-20th centuries, individual electric motors at each lathe replaced line shafting as the power source.
Beginning in the 1950s, servomechanisms were applied to the control of lathes and other machine tools via numerical control, coupled with computers to yield computerized numerical control. Today manually controlled and CNC lathes coexist in the manufacturing industries. A lathe may or may not have legs known as a nugget, which sit on the floor and elevate the lathe bed to a working height. A lathe may sit on a workbench or table, not requiring a stand. All lathes have a bed, a horizontal beam. Woodturning lathes specialized for turning large bowls have no bed or tail stock a free-standing headstock and a cantilevered tool rest. At one end of the bed is a headstock; the headstock contains high-precision spinning bearings. Rotating within the bearings is a horizontal axle, with an axis parallel to the bed, called the spindle. Spindles are hollow and have exterior threads and/or an interior Morse taper on the "inboard" by which work-holding accessories may be mounted to the spindle. Spindles may have exterior threads and/or an interior taper at their "outboard" end, and/or may have a hand-wheel or other accessory mechanism on their outboard end.
Spindles are impart motion to the workpiece. The spindle is driven either by foot power from a treadle and flywheel or by a belt or gear drive to a power source. In most modern lathes this power source is an integral electric motor either in the headstock, to the left of the headstock, or beneath the headstock, concealed in the stand. In addition to the spindle and its bearings, the headstock contains parts to convert the motor speed into various spindle speeds. Various types of speed-changing mechanism achieve this, from a cone pulley or step pulley, to a cone pulley with back gear, to an entire gear train similar to that of a manual-shift auto transmission; some motors have electronic rheostat-type speed controls, which obviates cone gears. The counterpoint to the headstock is the tailstock, sometimes referred to as the loose head, as it can be positioned at any convenient point on the bed by
Cemented carbide is a hard material used extensively as cutting tool material, as well as other industrial applications. It consists of fine particles of carbide cemented into a composite by a binder metal. Cemented carbides use tungsten carbide, titanium carbide, or tantalum carbide as the aggregate. Mentions of "carbide" or "tungsten carbide" in industrial contexts refer to these cemented composites. Most of the time, carbide cutters will leave a better surface finish on the part, allow faster machining than high-speed steel or other tool steels. Carbide tools can withstand higher temperatures at the cutter-workpiece interface than standard high-speed steel tools. Carbide is superior for the cutting of tough materials such as carbon steel or stainless steel, as well as in situations where other cutting tools would wear away faster, such as high-quantity production runs. Cemented carbides are metal matrix composites where carbide particles act as the aggregate and a metallic binder serves as the matrix.
Its structure is thus conceptually similar to that of a grinding wheel, except that the abrasive particles are much smaller. The process of combining the carbide particles with the binder is referred to as sintering or hot isostatic pressing. During this process, the binder will be entering the liquid stage and carbide grains remain in the solid stage; as a result of this process, the binder is embedding/cementing the carbide grains and thereby creates the metal matrix composite with its distinct material properties. The ductile metal binder serves to offset the characteristic brittle behavior of the carbide ceramic, thus raising its toughness and durability. By controlling various parameters, including grain size, cobalt content and carbon content, a carbide manufacturer can tailor the carbide's performance to specific applications; the first cemented carbide developed was tungsten carbide which uses tungsten carbide particles held together by a cobalt metal binder. Since other cemented carbides have been developed, such as titanium carbide, better suited for cutting steel, tantalum carbide, tougher than tungsten carbide.
The coefficient of thermal expansion of cemented tungsten carbide is found to vary with the amount of cobalt used as a metal binder. For 5.9% of cobalt a coefficient of 4.4 µm·m−1·K−1 is found, whereas the coefficient is around 5.0 µm·m−1·K−1 for a cobalt content of 13%. Both values are only valid from 20 °C to 60 °C. Carbide is more expensive per unit than other typical tool materials, it is more brittle, making it susceptible to chipping and breaking. To offset these problems, the carbide cutting tip itself is in the form of a small insert for a larger tipped tool whose shank is made of another material carbon tool steel; this gives the benefit of using carbide at the cutting interface without the high cost and brittleness of making the entire tool out of carbide. Most modern face mills use carbide inserts, as well as many lathe endmills. In recent decades, solid-carbide endmills have become more used, wherever the application's characteristics make the pros outweigh the cons. To increase the life of carbide tools, they are sometimes coated.
Five such coatings are TiN, TiC, TiN, TiAlN and AlTiN. Most coatings increase a tool's hardness and/or lubricity. A coating allows the cutting edge of a tool to cleanly pass through the material without having the material gall to it; the coating helps to decrease the temperature associated with the cutting process and increase the life of the tool. The coating is deposited via thermal CVD and, for certain applications, with the mechanical PVD method. However, if the deposition is performed at too high temperature, an eta phase of a Co6W6C tertiary carbide forms at the interface between the carbide and the cobalt phase, which may lead to adhesion failure of the coating. Mining and tunneling cutting tools are most fitted with Cemented Carbide tips, the so-called "button bits". Only artificial diamond can replace the cemented carbide buttons when conditions are ideal, but as rock drilling is a tough job the Cemented Carbide button bits remain the most used type throughout the world. Since the mid-1960s, steel mills around the world have applied cemented carbide to the rolls of their rolling mills for both hot and cold rolling of tubes and flats.
This category contains a countless number of applications, but can be split into three main areas: Engineered components Wear parts Tools and tool blanksSome key areas where cemented carbide components are used: Automotive components Canning tools for deep drawing of two-piece cans Rotary cutters for high-speed cutting of artificial fibres Metal forming tools for wire drawing and stamping applications Rings and bushings for bump and seal applications Woodworking, e.g. for sawing and planing applications Pump pistons for high-performance pumps Nozzles, e.g. high-performance nozzles for oil drilling applications Roof and tail tools and components for high wear resistance Balls for ball