Abstract: A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R2/R1 of a diameter R2 of a front end of each of the carbon electrodes to a diameter R1 of a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter R3 of a base end side to the diameter R2 of the front end. When a length of the diameter reduction portion is L1, the diameter of the front end is R2, the diameter of the base end is R1, an angle between the axis lines of the carbon electrodes is ?1, and X=(R1?R2)/2, a value of L1?(X/tan(?1/2)) is set in a range of 50 to 150 mm.

Abstract: The invention proposes a process for the production of a container made from glass, in the form of a hollow body open on both ends for pharmaceutical and medical applications, in particular in the form of a syringe barrel, where a glass drop (14) is dispensed from a melting unit, is placed into a mold (12) that is driven to rotate, and is formed by the effect of the centrifugal force, the mold being driven at a rotational speed of at least 5000 rpm, preferably approximately 50000 rpm.

Abstract: A mold for the production of a silica crucible by heat-fusing silica or quartz powder attached onto an inner wall of a rotating mold, wherein a ring-shaped heat insulating barrier material having a specified inner diameter is disposed on an inner peripheral wall of an upper opening portion of the mold corresponding to an upper region of the silica crucible.

Abstract: In a mold for use in the production of a silica crucible, a mold cover corresponding to a small-diameter thinned portion of an upper part of the silica crucible is detachably disposed on a mold substrate corresponding to a main body of the silica crucible, and the mold cover has a barrier function against arc heating, and an inner diameter of the mold cover is smaller than that of the mold substrate but larger than that of the silica crucible.

Abstract: There is provided a mold for use in the production of a silica crucible by heat-fusing silica or quartz powder attached onto an inner wall of a rotating mold, wherein an inner side of an upper opening portion of the mold corresponding to an upper part of the silica crucible is ground to obtain a step portion and a ring-shaped heat insulating barrier member having an inner diameter smaller than that of the mold is disposed on the step portion through a hollow disk-shaped support member having an inner diameter equal to or somewhat larger than that of the heat insulating barrier member.

Abstract: In a mold for use in the production of a silica crucible, a cylindrical rim member is engagedly supported through hooks to an inner side of an upper opening portion of the mold corresponding to an upper part of a silica crucible and an outer diameter of the rim member is smaller than an inner diameter of the mold but larger than an inner diameter of the silica crucible.

Abstract: A rotating mold has a plurality of air channels that communicate with a cavity formed in the mold. Silica grain is deposited in the rotating mold and then formed into the shape of a crucible having a lower portion that comprises a substantially uniformly thick wall. An upper portion of the grain is formed into a substantially narrowed wall portion about the perimeter of the formed shape. The silica grain is heated, and a pump draws gas through the air channels while the silica fuses. There is a pressure drop across the narrowed wall portion. After fusing, the upper portion of the crucible, including the narrowed wall portion, is cut off.

Abstract: Disclosed is a lower molding die for receiving a molten glass droplet which is dripped. A cover layer is formed on a substrate with an intermediate layer therebetween, and a roughening process is performed on the surface of the cover layer in order to increase arithmetic average roughness Ra. The surface of the cover layer subjected to the roughening process has an arithmetic average roughness Ra of 0.01 ?m or more, and an average length RSm of a roughness curvilinear element of 0.5 ?m or less.

Abstract: A method is provided for producing a vitreous silica crucible having excellent shape formability and fewer internal bubbles without excessively heating the curved portion and the bottom part. The method comprises arc melting a quartz powder molded product loaded in a rotating mold while performing vacuum suction, wherein the electrode is moved sideways with respect to the mold center line upon the initiation of arc melting or during the arc melting, and the arc melting is performed at an eccentric position, and preferably the time for total heating is limited to 60% or less of the total arc melting time. A vitreous silica crucible produced by this method is also provided.

Abstract: A method and a machine for the production of hollow glassware articles, by the blow-and-blow, press-and-blow, press-and-blow paste mold and direct-press processes in a glassware forming machine including single or multiple machine sections each having single or multiple-cavity, comprising: forming a parison in an inverted orientation, into a blank mold and a first transferable and open-able neck ring mold held by an inverting apparatus having a first and a second diametrically opposed arms, each arm holding a transferable and open-able neck ring mold; inverting the parison held by the first transferable and open-able neck ring mold, by rotating the first arm 180° to an upright orientation at an intermediate station, while the second arm with a second transferable and open-able neck ring mold is simultaneously placed at the parison forming station; transferring the first transferable and open-able neck ring mold holding the parison in an upright orientation, from the intermediate station, to a blow mold statio

Abstract: The device for blank pressing glass bodies includes a first rotary indexing table with preforms for forming parisons from glass gobs; a second rotary indexing table having pressing molds and pressing tools for pressing the parisons into final form after formation in the preforms; and a device for shifting the first rotary indexing table relative to the second rotary indexing table so that each preform is positionable in a transfer position between a pressing tool and a pressing mold. Each preform is mounted on the first rotary indexing table by a indexable mount for holding it in a first horizontal position or in a second position pivoted away from the first position, so that, when a preform is in the transfer position, the indexable mount can be pivoted, so that a parison in it drops into the pressing mold for pressing by the pressing tool.

Abstract: In order to provide a quartz glass crucible distinguished by high purity, high opacity and/or low transmissibility in the IR spectrum, it is proposed on the basis of a known quartz glass crucible of opaque quartz glass with a crucible body symmetrical in relation to a rotational axis, an outer zone (3) of opaque quartz glass transitioning radially toward the inside into an inner zone (2) of transparent quartz glass and with a density of at least 2.15 g/cm3, that according to the invention, the crucible body (1) be made of a synthetic SiO2 granulate with a specific BET surface ranging from 0.5 m2/g to 40 m2/g, a tamped volume of at least 0.8 g/cm3 and produced from at least partially porous agglomerates of SiO2 primary particles.

Abstract: Systems and methods for large scale synthesis of germanium selenide glass and germanium selenide glass compounds are provided. Up to about 750 grams of a germanium selenide glass or a glass compound can be synthesized at a time in about eight hours or less. Stoichiometrically proportional amounts of germanium and selenium are placed in an ampoule. A variable may also be placed in the ampoule. The ampoule is heated to above the softening temperature of the glass or glass compound being synthesized. The ampoule is then rocked for a period of time while the temperature is held constant. The temperature of the ampoule is then brought down to above the softening temperature of the glass or glass compound being synthesized and then quenched.

Abstract: Present invention suppresses undesirable effects of the bubbles trapped in a silica glass crucible on single crystallization during the pulling process under a high-temperature load. When raw material powder is melted in a mold 1, graphite components of electrodes and impurities contained in the raw material are removed by introducing hydrogen gas and/or oxygen gas immediately after the start of arc discharge. Graphite and impurities are prevented from entering the product crucible, thereby suppressing the volume increase rate of the bubbles and reducing the inner pressure of the bubbles. Gases remaining in voids of an accumulated layer of silica powder formed inside the mold 1 can be replaced with helium gas, by supplying helium gas to the accumulated layer from the mold 1.

Abstract: An apparatus for manufacture of quartz crucibles comprising a hollow mold having a bottom wall portion and a side wall portion and defining a hollow space therein. The walls of the mold include a plurality of openings to facilitate gas passage therethrough. A rotatable support of the mold is provided to rotate the mold about a vertical axis. A vacuum is applied through the walls of the mold to draw quartz particles against the walls and remove gas. A shroud surrounds at least a portion of the hollow mold; at least one gas inlet positioned to provide a gas to a space between the shroud and the mold. A housing overlaps at least a portion of the shroud and the hollow mold. At least one gas outlet is positioned to exhaust gas which may exit the space between the shroud and the mold. Alternatively, or in addition to the outlet, a space may be provided between the housing (hood) and the shroud to facilitate gas discharge.

Abstract: In a device (5) for producing a quartz glass crucible (2) a section (14, 15) of a wall (13) of a rotating quartz glass crucible (2) is heated by at least two electrode arrangements (7, 8) which are evenly spaced along the periphery of the quartz glass crucible (2) and create a first and a second electric arc. The use of a plurality of electrode arrangements (7, 8) allows a reduction of the cooling phase of the section (14, 15) i.e. the time until it reaches the next heating zone (11, 12), so that undesirably high temperature differentials in the wall (13) are prevented. At the same time the required heat output of each individual electrode arrangement (7, 8) can be reduced so that vaporization and the concurrent bubble formation is reduced. In addition to the higher levels of quality attainable hereby, the duration of the manufacturing process is also reduced.

Abstract: In a method for producing a streak-free quartz glass sheet with a highly homogeneous degree of refraction, a quartz glass rod is lowered into a melting pot parallel to a longitudinal axis of the quartz glass rod. A cross-section of the melting pot is larger than a cross-section of the quartz glass rod and determines a contour of the quartz glass sheet. The quartz glass rod is heated in the melting pot to a flow temperature whereupon the quartz glass rod is lowered until the quartz glass rod melts and a height of the quartz glass flowing in the melting pot reaches a desired quartz glass sheet thickness. The melting pot and the quartz glass rod move relative to each other in a direction which is perpendicular to the longitudinal axis of the quartz glass rod during the melting process. Preferably, the movement involves a rotational and a transverse movement.

Abstract: An apparatus and process for fabricating tubing used in the making of chalcogenide fibers. The apparatus features a three-sectioned melt/spin ampoule that allows for fabricating the chalcogenide tubing without introducing impurities and contaminants, in a self-contained apparatus.

Abstract: A method is provided for molding a synthetic silica glass member. The method includes accommodating a synthetic silica glass bulk inside a molding vessel; interposing an elastic member having a ventilating property between a pressing member and the synthetic silica glass bulk; providing a fastener for fastening at least peripheral edge portions of the elastic member to the pressing member; and pressing the synthetic silica glass bulk against the molding vessel by the pressing member in a high-temperature condition to mold the synthetic silica glass bulk into a synthetic silica glass member having a shape conforming to a shape of the space defined by the pressing member and the molding vessel, the synthetic silica glass bulk being pressed in such a manner that the pressing member and the elastic member tightly fasten to each other through the fastener.

Abstract: The invention provides a method for manufacturing quartz glass large scale slab ingot in a flame hydrolysis reaction in a furnace, including the steps of rotating the furnace, depositing a fused silica on a furnace bed, and extending the deposit outwardly by heating and rotation of the furnace, thereby a quartz glass slab ingot is obtained. A quartz glass burner is installed at the ceiling of the furnace, hydrogen gas supplied to the burner is flowing down along the tapered wall of the oxygen chamber and being ejected into the outer casing part of the hydrogen gas is deflected to the center of the burner, and mixed with the oxygen just after the ejecton from the oxygen gas nozzles thereby the flame is formed smoothly and the thermal efficiency is improved, The flame becomes wide enough and the silica powder transported by the hydrogen gas is uniformly fused by the flame and heat capacity of the fused silica.

Abstract: Fused silica boules (19) having improved radial homogeneity are produced by controlling the air flow around the boule (19) during its formation. The boule is formed in a cup-like containment vessel (13) which collects silica particles from a plurality of burners (14). The containment vessel (13) rotates and oscillates relative to the burners (14) as the boule (19) is formed. The containment vessel (13) is bounded by a cup-like containment wall (22), and a shadow or air flow wall (130) is spaced apart from and surrounds the containment wall (22) forming a gap or air flow passage (175) therebetween. A radially-outwardly extending deflecting wedge portion (23) is formed at the upper extent of the containment wall (22) and at an outlet end of flow passage (175).

Abstract: Cobalt alloys are disclosed for use in the fabrication of spinner discs for fiberizing molten glass into fibers in rotary fiberizing processes. The cobalt alloys fall within the following ranges, in percentage by weight, Co 22.0-54.0; Cr 30.0-34.0; Ni 9.0-31.0; Mo 0.0-7.0; C 0.45-0.65; Si 0.25-1.0; Mn 0.30-0.80; precious metals (PM) 0.0-2.0; and carbide forming metals (CFM) 0.0-1.3.

Abstract: Methods and apparatus for manufacturing silica crucibles 9 containing few, if any, white point defects. The white point defects are reduced by decreasing the amount of silica vapor condensing on electrodes 4,5,6 used in the manufacturing process. The silica vapor condensation is decreased by providing a flow of a protective or non-reactive gas or gas mixture through protective devices 11,12,13, over portions of the electrodes where the silica vapor would otherwise condense.

Abstract: A method for producing zirconia fused cast refractories, which comprises casting zirconia fused cast refractories containing at least 33 wt % of a ZrO.sub.2 component utilizing a mold, wherein the mold is rotated on a rotation axis, so that at least a portion of a meltage of raw material poured into the mold, is cooled to solidify under a centrifugal force of at least 1.2 G.

Abstract: In a quartz glass crucible obtained by heating and fusing a rotating layer (3) charged with a powder of silicon dioxide, impurity elements are controlled so that copper, chromium, and nickel each amount to 0.5 ppb or less, iron amounts to 120 ppb or less, and sodium amounts to 20 ppb or less. The silicon dioxide powder is supplied to a rotatable mold (1) having an open top, thereby forming a layer (3) charged with silicon dioxide along the inner peripheral wall of the mold. The layer (3) is internally heated and fused while covering the open top with a lid (5) having two or more holes (6,7), and the mold (1) is ventilated to discharge the high temperature gases through the holes (6,7).

Abstract: A method of making a quartz dome for a reactor chamber from a substantially flat quartz disk. The quartz disk is placed on a graphite ring which is rotated. The quartz disk is heated until the disk is softened slightly and it begins to slump. The softened portion of the disk is drawn by a change in pressure to contact a fixed wiper blade. The wiper blade controls the size and shape of the deformation of the quartz disk to form the dome surface.

Abstract: The disclosed process involves the feeding of particulate SiO.sub.2 into a rotating cylindrical furnace in which a gas plasma arc has been established, for melting the feed at a temperature of at least 2400.degree. C. The feed rate is regulated so that the rate of growth of the radius of the ingot melt will not exceed the rate at which bubbles move through the melt to the inner cylindrical surface. The preferred apparatus is a rotating horizontal furnace having a pair of opposing hollow electrodes mounted in its opposing end surfaces for establishment of an arc therebetween. A feeding device introduces the SiO.sub.2 feed through the open bore of one of the electrodes for melting by the plasma arc.

Abstract: An apparatus for making a quartz glass crucible comprises a housing having a first chamber and a second chamber therein, a rotation crucible having an inner surface corresponding in configuration to the quartz glass crucible, means for rotating the rotation crucible, means for shifting the rotation crucible and the rotating means together between the first and second chambers, means placed in the first chamber for feeding a grain material into the rotation crucible, means placed in the first chamber for shaping the grain material in the rotation crucible so as to form a shaped body in the shape of the quartz glass crucible when the rotation crucible rotates, and means placed in the second chamber for heating and fusing the shaped body within the rotation crucible so as to make the quartz glass crucible.

Abstract: Apparatus for removing a fused silica glass object from a rotating pot has a gripping member which grips the upper rim of the fused silica glass object and a rotational synchronization member connected to the gripping member which is lowered vertically into frictional contact with the rotating pot. The rotation of the pot drives the rotation of the synchronization member which drives the rotation of the gripping member. The object can be withdrawn vertically from the pot without the angular velocities of the object and pot diverging.

Abstract: A dental centrifugal casting apparatus includes a crucible for receiving a dental casting material, a crucible holding unit for holding the crucible, a heating furnace such as a high-frequency induction heating furnace for heating and melting the dental casting material in the crucible, a crucible forward and backward rotary driving unit for driving the crucible holding unit forward and backward so as to insert the crucible into the heating furnace to heat and melt the material in the crucible and remove the crucible from the furnace, and for rotationally driving the crucible holding unit so as to inject the melted material into a mold at a predetermined position, a bucket for holding the mold in which the molten material is injected by the forward and backward motion and the rotation of the crucible performed by the crucible forward and backward rotary driving unit, and a centrifuge unit for rotating a rotary arm swingably mounting the bucket on its end portion at high speed immediately after the material is

Abstract: This invention relates to a method of making an object of silica glass, such as a crucible, according to which a pot capable of rotating about its axis is filled with a refractory pulverulent material. The pot is rotated and a cylindrical cavity is formed in the material, the axis of which coincides with that of the pot. The bottom and the wall of the cavity are then formed to a certain thickness with a silica-rich material. This silica-rich material is melted, the object thus produced is cooled and then extracted vertically by an extraction mechanism comprising a gripping member which is rotating, at least initially, at the same speed as the pot.

Abstract: A flat-bottomed quartz glass crucible for the manufacture of monocrystalline silicon is made by disposing granular quartz particles on a flat base in a cylindrical mold. A vacuum is drawn on the particles through vacuum holes in the base to retain the particles on the base while the base and mold are rotated, and while the particles are heated to fuse them into a quartz glass crucible shape.

Abstract: A quartz glass crucible adapted for use in a process for pulling a single crystal semiconductor material having an opaque outer substrate of a quartz glass with a relatively high bubble content and an inner transparent glass layer which is substantially free from bubbles. The crucible is produced while the substrate is supported by a rotating mould by forming an atmosphere of high temperature gas and supplying a metered quantity of powders of quartz to the high temperature gas atmosphere to have the quartz powders molten at least partly and directed toward an inner surface of the substrate to be adhered thereon.

Abstract: A centrifugal casting device adapted to mold and cast a casting material melted by a casting material melting means, by the centrifugal force of a rotary arm, in a mold disposed on the centrifugal side of the arm through a casting crucible disposed at one end of the arm, in which device the melting means is designed to move outside the path of rotation of the arm at least when the arm is rotated so as to reduce the force of rotation of the arm to thereby increase efficiency of casting. And also a centrifugal casting device having the above features in which device the righting reaction of a charged compression spring is used as the driving force of the rotary arm and further included a clutch member and sensors so that the rotary arm stops as soon as possible at the end of casting and returns automatically to its normal position after stopping so as to be ready for the next step of casting and so as to automatically keep the force of rotation of the arm invariably constant.

Abstract: In the manufacture of a quartz glass crucible of low bubble content, a first layer of granular quartz material is disposed on the interior of a rotating mold through the walls of which a vacuum can be drawn. A second layer of finer quartz material is then disposed on the first layer. The quartz material is then heated, melted and fused to form a crucible.

Abstract: An apparatus is provided for inserting molds containing a dosed monomeric mixture into a rotating polymerizing column by means of an alternate pushing and releasing of a column of molds falling from tubular magazines connected to said polymerizing column. Said apparatus comprises a body fabricated from a non-magnetic material which is adapted on its lower end for a firm affixation to the column and on its upper end for affixation to the magazine, and being provided with a through-opening of a diameter which is larger than the diameter of the molds, another through-hole, leading to said through-opening, which is formed perpendicularly to the axis of the said through-opening, movable jaws being movable one against the other and moved in the direction of the center by springs, and two stationary blocks placed outside said body in an opposite position while at least the outer ends of the jaws and the stationary blocks are constructed from materials which provide a mutual counterpole magnetic interaction.

Abstract: A centrifugal casting device employing a rotatable polymerization column adapted to accommodate a plurality of vertically aligned molds and a rotatable mold-dispensing magazine disposed at an angle .alpha. to the polymerization column and adapted to dispense molds one at a time into the polymerization column.

Abstract: A device for the centrifugal casting of articles in a rotatable polymerization column which includes retaining means disposed in the lower end of the column for communicating with a mold therein whereby the rotational speed of said mold and other vertically arranged molds above it are made substantially synchronous with the rotational speed of the column.

Abstract: A centrifugal casting device and method employing a rotatable polymerization column adapted to accommodate a plurality of vertically aligned molds and being associated with an arrangement of advancing means and mold feeding means which are synchronized to intermittently and automatically advance a mold containing a polymerizable or curable composition in the mold cavity over the polymerization column and then automatically force feeding said mold into the polymerization column.

Abstract: A device and method for spin casting articles, such as lenses, employing a rotatable polymerization column in conjunction with a plurality of molds such that the column is adapted to accommodate a plurality of gravity fed molds in a loose mating engagement that insures rotation of the molds to be synchronized to the speed of rotation of the column to produce quality spun cast articles.

Abstract: A device and method for spin casting articles such as lenses employing a polymerization tube in conjunction with a plurality of molds such that the tube is adapted to accommodate the plurality of molds in an interference fitting and sliding relationship so that rotation of the polymerization tube will cause the molds to rotate at the same speed while maintaining the concentricity of the molds to the spinning axis of the tube to produce quality spun cast articles.

Abstract: To make quartz glass crucibles suitable for drawing of single crystal silicon for electronic semiconductor applications, granular crystalline quartz or amorphous quartz glass is introduced into a rotating hollow mold which has gas-pervious wall regions at the side walls and bottom thereof, for example by having bores extending through a metal mold or being made of porous, sintered material. After introducing the raw material, a heat source, such as an electric arc, is introduced into the hollow mold, causing first sintering and then melting of an inner layer; upon introduction of the hollow mold, a vacuum is applied to the outside of the hollow mold, for example between the housing and the mold body, and, during continued rotation, to draw out any included gases and cause melting-together of vacuoles which, otherwise, might form due to included spaces and gases within the granular filling material.

Abstract: A centrifugal casting apparatus comprises a mold mounted for rotation about the vertical axis thereof and having a bottom provided with a through axial opening. A member having a helicoidally shaped surface is axially mounted within the opening in the bottom. The member has a lower portion to be immersed into a melt and extending out of the opening and downwardly of said bottom of the mold. The mold and the member are connected with a rotation drive and a vertical motion drive.

Abstract: The elongated burner is described which is capable of providing a ribbon of flame through which particulate material as small as 1 micron is uniformly dispersed and transported onto a rotating forming surface for formation of an ingot. In a preferred embodiment the burner is provided with a hollow interior defined by a cylindrical surface interrupted by a longitudinal groove in communication with a longitudinal discharge slot. The sides of the groove are sloped at an angle steeper than the angle of repose of the particulate material. In the preferred embodiment the exterior surface of the burner is likewise provided with a longitudinal groove in communication with the discharge slot and providing two surfaces angled toward each other and toward the path through which the discharged material travels.

Abstract: Conoid surfaces can be generated by rotation of a material at different angles and under differing constraints. An axis of 45.degree. can produce hyperboloids; with perpendicular axes, concentric spheres can be produced; magnetic fields can be used to shape the lenses; and multielement lenses can be produced with special chambers.

Abstract: The apparatus for manufacturing an ingot includes a rotatable housing with an inner surface defining an opening therethrough along the rotational axis of the housing. The housing is rotated about the rotational axis. The housing includes a layer of insulating material located between the inner and outer surfaces of the housing. Particulate material is deposited along the inner surface while the housing is rotating and the particulate material is heated above its melting temperature while the housing is rotating, the rotational movement holding the molten particulate material in place by centrifugal force on the inner surface for forming an ingot.

Abstract: An improved apparatus for the transfer of mold rings in a centrifugal casting process. One type of forming process for the funnel portions of color television picture tube envelopes utilizes a centrifugal casting process for the glass. This process requires a main mold body. An indexing mechanism moves from a station at which the mold ring is deposited on the main mold to a station where the mold ring is removed from the main mold after completion of the casting process. A movable shuttle member is connected to pivotally mounted pairs of support fingers for the mold rings through connecting rods. An external drive motor operates a single actuator at each machine cycle. This single actuator causes the entire shuttle to shift and a mold ring to be deposited at one station and a second mold ring to be simultaneously picked up at another station. Because of the mechanical linkage design, one pair of support fingers always opens while all the others close when the single actuator is operated.

Abstract: Conoid surfaces can be generated by rotation of a material at different angles and under differing constraints. An axis of 45.degree. can produce hyperboloids; with perpendicular axes, concentric spheres can be produced; magnetic fields can be used to shape the lenses; and multielement lenses can be produced with special chambers.

Abstract: A vapor shield supporting ring is attached to the envelope of a vacuum device. The supporting ring is embedded in the inner wall of the envelope and extends into the interior of such envelope. A welding flange is mounted on the interior portion of the ring. The ring does not extend to the exterior wall of the envelope. To embed the ring in the envelope, the ring is suspended by a holding means such as a magnet, which is placed into the desired position within a centrifugal mold. The molten glass is poured into the mold and the mold is spun, thereby flowing the glass along the walls and surrounding the outer portion of the supporting ring. When the glass solidifies, the supporting ring is firmly embedded in the wall of the envelope.

Abstract: A new method for preparing low loss multimode and monomode glass optical fibers which avoids casting or pouring the core and clad melts is disclosed. The new technique is based on a reactive-gas-transport approach which avoids contamination from absorbing impurities and scattering centers by reacting the glass melt with reactive gases which remove impurities and increase the refractive index of the fiber.