Abstract: Emission abatement system. The system includes a source of emissions and a catalyst for receiving the emissions. Suitable catalysts are absorber catalysts and selective catalytic reduction catalysts. A plasma fuel converter generates a reducing gas from a fuel source and is connected to deliver the reducing gas into contact with the absorber catalyst for regenerating the catalyst. A preferred reducing gas is a hydrogen rich gas and a preferred plasma fuel converter is a plasmatron. It is also preferred that the absorber catalyst be adapted for absorbing NOx.

Abstract: A three-way catalyst (10) is provided in the exhaust passage (9) of an engine (1) which stores and releases oxygen according to the oxygen concentration in the exhaust gas. A controller (2) calculates an oxygen storage amount of the catalyst (10) by accumulating a variation rate of the oxygen storage amount of the catalyst (10) based on the oxygen amount in the exhaust gas (S3-S5). A target oxygen amount in the exhaust gas is calculated which reduces the difference of the oxygen storage amount from a target oxygen storage amount (S6). A target air/fuel ratio is calculated based on a catalyst deterioration coefficient, an exhaust gas flowrate and the target oxygen amount (S7). Due to this process, it is possible to increase the speed and accuracy of control of the oxygen storage amount of the catalyst (10) towards the target oxygen storage amount.

Abstract: A system and method are disclosed for operating an internal combustion to provide a temperature rise in an exhaust aftertreatment device. An exhaust valve is actuated during a compression stroke to release unburned fuel and air. The fuel oxidizes with the air in the exhaust aftertreatment device causing an exotherm. The opening and closing time of the exhaust valve are determined to cause the desired amount of fuel and air to be released into the exhaust aftertreatment device.

Abstract: When a NOx-releasing unit is operated to change an air-fuel ratio to a rich side to thereby establish a low-oxygen-concentration atmosphere of an exhaust gas such that NOx is released from a NOx catalyst, a reducer-supplying unit 33 additionally supplies a reducer during an operating period of the NOx-releasing unit for reducing NOx released into an exhaust path such that release of NOx balances with reduction of NOx, thereby reducing NOx released from the NOx catalyst and thus suppressing worsening of exhaust gas performance.

Abstract: A method for controlling diesel engine emissions is disclosed. The diesel engine's exhaust system has a NOx oxidation catalyst, a diesel particulate filter (DPF), and a lean NOx trap (LNT). The DPF is monitored to determine the need for regeneration. The LNT is monitored to determine the need for regeneration or desulfurization. A fuel injector is used to inject fuel upstream of the LNT under certain conditions, and a bypass may be used to bypass exhaust around the oxidation catalyst to provide richer or hotter exhaust to the LNT.

Abstract: The exhaust emission of a hybrid vehicle is improved by providing a technology of achieving effective functioning of a regenerative catalytic apparatus by utilizing a feature of the hybrid vehicle of being driven by selectively operating an internal combustion engine and an auxiliary power source. The regenerative catalytic apparatus in a hybrid vehicle is provided with a hybrid mechanism for driving the vehicle by selectively operating an internal combustion engine and an auxiliary power source; an exhaust-purifying catalyst provided in an exhaust passage of the internal combustion engine for purifying exhaust flowing in the exhaust passage; and heat-storage mechanism for storing heat generated in the internal combustion engine while the internal combustion engine is in an operating state, and utilizing the stored heat to suppress decrease in the temperature of the exhaust-purifying catalyst after the internal combustion engine is stopped.

Abstract: A hydraulic circuit branch includes a hydraulic actuator, such as a cylinder, and an assembly of one or more electrohydraulic proportional valves connected in series between a pressurized fluid supply line and a tank return line. The force acting on the hydraulic actuator is determined by sensing fluid pressures produced by the hydraulic actuator. Pressures in the supply and tank return lines also are sensed. The sensed pressures and a desired velocity for the hydraulic actuator are employed to determine an equivalent flow coefficient, which characterizes fluid flow through the hydraulic circuit branch, either a conduction or restriction coefficient may be derived. The equivalent flow coefficient is used to determine how to activate each electrohydraulic proportional valve to achieve the desired velocity of the hydraulic actuator. The equivalent flow coefficient also is employed to control the pressure levels in the supply and tank return lines.

Abstract: The invention relates to a device for generating electric energy from the kinetic energy of vehicles. Said device comprises at least one pressure reservoir (13) for a fluid. Said pressure reservoir is arranged in the pavement and has at least one pressure chamber that is compressible in a substantially rectangular direction to the pavement, at least one circuit for the fluid, a component of the fluid circuit representing the pressure chamber, and at least one turbine/generator system (86) arranged in the fluid circuit for generating electric energy from the flow of the fluid.

Abstract: A hydroelectric power plant uses a plurality of windmills connected to compressed air generators to produce pressurized air. Pressurized air is used to drive water through a turbine to produce electrical power. The water is recycled and the power plant includes reserve pressurized air tanks to allow the plant to continue to operate when the wind levels are not sufficient to produce high pressure air. The power plant is designed to be operated on a continuous basis based on wind power. When the wind subsides and the reserve capacity has been exhausted, electricity can be drawn from the local utility supplier. When excess power is generated by the power plant, electricity from the power plant can be added to the grid of the local electricity supplier.

Abstract: An hydraulic power assembly 10 is provided, including at least one primary hydraulic power unit 20 supplying hydraulic fluid 30 to a hydraulic system 34, and a contingency hydraulic power unit 50 utilizing the orbiter's helium storage tank 52 to power a contingency hydraulic drive 56 to supply hydraulic fluid 30 from a contingency hydraulic fluid reserve 58 to the hydraulic system 34 during peak loading conditions.

Abstract: A balance of force acting on a pool 21 of a control valve 20 is expressed by (P1−P3)·A=F+f When it is assumed that a pressure difference P1−P2 before and after a throttle 42 is &Dgr;P12 to modify the above expression, an expression &Dgr;P12·A+(P2−P3)·A=f+F is obtained. According to the present invention, the force &Dgr;P12·A corresponding to the pressure difference &Dgr;P12 before and after the second throttle 42 of the first term of the left-hand side is applied to the control valve 20 as a force capable of canceling the flow force f at the first term of the right-hand side.

Abstract: A system and method of adjusting the power off positioning of a microactuator is disclosed. The microactuator has a first power off position and comprises a bimorph component. The bimorph comprises at least two materials, wherein the materials have different thermal expansion characteristics. When heated, the bimorph component of the microactuator bends due to asymmetric thermal expansion of the materials. If one of said materials is forced beyond a yield point, then when cooled, the actuator assumes a second power off position. The microactuator maintains the second power off position due to stress in the bimorph, which is induced by forcing the material beyond its yield point.

Abstract: A braking device comprising a master cylinder (2), a primary piston (3), a manual control member (4), a booster (6) coupled to the manual control member (4) and an emergency assist valve (VA). The emergency assist valve comprising a reaction piston (17) through which there passes a ratio control (T) having a head (26a) situated in a chamber (35) lying between the reaction piston (17) and a bushing (36) located further forward in a bore (18) in the primary piston. The bushing (36) has a bore (37) in which there can slide a rapid piston (38), the rear end (45) of which forms, with the head (26a) of the ratio control, a valve (C). The valve (C) is capable of closing the inlet to a passage (39) in the rapid piston against the action of a spring (41). The braking device comprises a means (26, 27, 30) for preventing a sharp retreat of the reaction piston (17) when the manual control member (4) is released after slow braking.

Abstract: A pair of flexible actuators according to the present invention is supported by a fixture made of a hard rubber at base ends of the flexible actuators. Each flexible actuator includes a movable unit that is capable of bending, a pump unit integrally connected to the movable unit at an end thereof, to control transfer of work fluid sealed in the movable unit, and a pump driver that controls driving of the pump unit. The movable unit includes two long and narrow tubes that each have an accordion wall, a core that maintains the tubes in parallel with each other, and a thin-film-bag-like cover that covers the tubes. The tube, which comes into contact with an object, is made of a soft material. The movable unit that is provided with the tube softly comes into contact with the object at a plurality of plane-contact portions of action of the movable unit, thereby holding the object without scratching the same.

Abstract: A control system for a variable geometry turbocharger having a turbine driven by exhaust gas delivered to an exhaust gas inlet of the turbocharger from an engine exhaust manifold and a compressor driven by the turbine to deliver air to an engine intake manifold via an air outlet of the turbocharger. The differential pressure across the engine is monitored, and a closed loop control system adjusts the variable geometry mechanism to prevent the differential pressure exceeding a predetermined limit. In engine braking mode the variable geometry mechanism may be actuated by a signal representative of the exhaust manifold pressure. An override circuit may be provided to control the variable geometry mechanism in the event of the turbocharger rpm exceeding a predetermined limit.

Abstract: A flywheel assembly for use with a supercharger having a rotatable shaft is provided. The flywheel assembly includes a flywheel configured to rotate about an axis of and be supported by the rotatable shaft and a clutch configured to selectively couple the flywheel to the rotatable shaft.

Abstract: A gas-turbine engine combustor having a plurality of venturi mixers, each includes an air inlet connecting to an air supply path, a fuel inlet connecting to a supply source of gaseous fuel, and an air-fuel mixture generating passage connecting to the air inlet and the fuel inlet and merges with an air-fuel mixture generating section to produce the air-fuel mixture and a first nozzle opened into the combustion chamber at an end of the air-fuel mixture generating passage.

Abstract: A gas turbine engine fuel injector conduit includes a single feed strip having a single bonded together pair of lengthwise extending plates. Each of the plates has a single row of widthwise spaced apart and lengthwise extending parallel grooves. Opposing grooves in each of the plates are aligned forming internal fuel flow passages through the strip from an inlet end to an outlet end. The feed strip includes a substantially straight middle portion between the inlet end and the outlet end. In one alternative, the middle portion has a radius of curvature greater than a length of the middle portion. The feed strip has at least one acute bend between the inlet end and the middle portion and a bend between the outlet end and the middle portion. The feed strip has fuel inlet holes in the inlet end connected to the internal fuel flow passages.

Abstract: A generating plant with improved capacity at high ambient temperatures comprises a gas turbine (32) matched to a generator (26) for summer peaking conditions. The plant includes a system for limiting turbine output at lower ambient temperatures to ensure that the generator or other components are not overloaded. It also preferably includes an evaporative cooler (70) for gas turbine inlet air.

Abstract: Methods and apparatus, both devices and systems, for control of Zeldovich (thermal) NOx production in catalytic combustion systems during combustion of liquid or gaseous fuels in the post catalytic sections of gas turbines by reducing combustion residence time in the HC zone through control of the HC Wave, principally by adjusting the catalyst inlet temperature. As the fuel/air mixture inlet temperature (to the catalyst) is reduced, the HC Wave moves downstream (longer ignition delay time), shortens the residence time at high temperature, thereby reducing thermal NOx production. The countervailing increase in CO production by longer ignition delay times can be limited by selectively locating the HC Wave so that thermal NOx is reduced while power output and low CO production is maintained. NOx is reduced to on the order of <3 ppm, and preferably <2 ppm, while CO is maintained <100 ppm, typically <50 ppm, and preferably <5-10 ppm.

Abstract: In a method for igniting a thermal turbomachine, the turbomachine containing a combustion chamber (30), an ignition device (10), a fuel supply (60) and an air supply (70), and the ignition device (10) consisting of an ignition space (50) and of an ignitor (51) arranged in the ignition space (50), the fuel supply (60) and the air supply (70) discharging into the ignition space (50), and the ignition space (50) being connected to the combustion chamber (30) via a flame tube (40), prior to the ignition of the combustion chamber (30), an overall fuel/air mixture ratio &PHgr;overall=1/&lgr;overall greater than 1, with &lgr;overall being the overall air ratio, is set in the flame tube (40) of the ignition device (10).

Abstract: A fastener (31) is disclosed for a first article, for example a tile (29), to a second article for example an outer wall (27) of a wall structure (21, 22) of a combustor (15) of a gas turbine engine (10). The fastener (31) comprises an elongate main part, which may be in the form of a bolt (34). The main part can extend through the first and second articles. The main part defines a cooling pathway (46) therethrough to allow the passage of a cooling gas through the main part.

Abstract: An integrated phase separator for use in an ultra high vacuum system, for example, a molecular beam epitaxy system, is described. The vacuum chamber has a cryogenic panel disposed therein. The cryogenic panel includes a cryogenic shroud region and a phase separator region. Liquid nitrogen is introduced into the cryogenic panel via an inlet line. As the liquid nitrogen warms and vaporizes, nitrogen vapor rises within the shroud. The phase separator region within the cryogenic panel provides a near atmospheric pressure vapor barrier over the liquid nitrogen so that the nitrogen vapor may escape smoothly through the outlet of the panel, without forming gas bursts. Also, the phase separator region is vacuum jacketed to prevent cryogenic shroud surface temperature changes due to variations in liquid nitrogen levels, thereby increasing the cryogenic shroud's pumping stability. In one embodiment, used in molecular beam epitaxy (MBE), the cryopanel is divided into first and second cooling chambers.

Abstract: A passive thermal control enclosure for transporting and storing payloads in earth orbit includes an inner box-like enclosure surrounded by an outer box-like enclosure with insulation in the space between the enclosures. The walls of the inner enclosure are fiber-matrix composite skins with honeycomb sandwiched therebetween. Each enclosure has its own door latched closed by releasable latches formed in opposed pairs that can be operated without any net force on the operator. Packs of phase change material (PCM) are placed into the inner enclosure with the payload. The PCM is contained in flexible packages. The packs of PCM are removed when they melt and replaced with fresh packs, and the melted packs preferably are re-frozen on-board the orbiting spacecraft. Freezing preferably is carried out such that the freeze front moves substantially in only one direction from one end of the pack to the other.

Abstract: A working medium is used which is composed of an R32 refrigerant or a mixed refrigerant containing at least 70 wt % of the R32 and a polyvinyl ether oil whose viscosity at 40° C. is 46-82 cst. Thus, a refrigeration system capable of improving COP while ensuring sufficient reliability using a working medium containing an R32 refrigerant having a low GWP (Global Warming Parameter) is provided.

Abstract: A defrost control system detects the variation in flow rate of refrigerant through an evaporator 8 while the flow is regulated to achieve a desired level of superheat at the outlet of the evaporator 8. When the flow rate becomes unstable, defrosting of the evaporator 8 is triggered.

Abstract: A chiller plant which produces chilled water for airconditioning, or an industrial process and which is comprised of chillers, cooling fluid pumps, and cooling towers with electrical motor drives uses a substantial amount of energy. A method that coordinates the operation of the cooling tower, cooling fluid pumps, and refrigeration machines so that the chiller plant operates at a higher overall efficiency thus reducing the power usage has been developed and is presented herein. The flow rate of the cooling fluid pumps are controlled to maintain a precise temperature difference across the refrigerant condenser. The cooling tower fans are controlled by comparing the cooling fluid temperature and the cooling fluid flow rate to selected design parameters. The heat rejection rate is measured for each chiller in the chiller plant and operating set points are established for each operating chiller to provide the optimum operation for best energy efficiency.

Abstract: A concentration cooling apparatus for a refrigerator includes a housing which is mounted in a cold air guiding path, and a nozzle which is rotatably supported in the housing, for concentratedly injecting cold air to a region where a high temperature load is generated when the high temperature load is generated in a predetermined region inside a cooling chamber. An infrared sensor is mounted at the front of the nozzle, for sensing the region where the high temperature load is generated. The sensor rotates together with the nozzle and a frost drying sensor is installed on the upper surface of the nozzle, for drying frost on the surface of the infrared sensor. Thus, the reliability of the infrared sensor can be improved by preventing the formation of frost on the surface of the lens of the infrared sensor which detects whether the high temperature load is generated.

Abstract: A method for controlling at least one electronic expansion valve coupled to an economizer in a refrigeration system in order to dynamically control the refrigeration system operating conditions and in order to accommodate more than one set of operating conditions. The system can also be used to control the capacity of the system. More specifically, the method can include determining the required capacity of the system and adjusting the flow of refrigerant through the electronic expansion valve to adjust the actual capacity of the system toward the required capacity of the system. In another aspect of the invention, the system is operated to maintain the power of the system below a threshold value (e.g., below a max rated horsepower).

Abstract: A power distributing mechanism distributes a power at a first axis from the engine to a second axis coupled to a motor generator, and a third axis coupled to a compressor for air conditioning. A clutch mechanism provides the connection/disconnection of the second axis to/from the third axis, and a lock mechanism provides the locking and unlocking of rotation of the third axis. The control unit inhibits switching operations of the clutch mechanism and lock mechanism for a startup transition period of the engine and a to-stop transition period of the engine and controls the inverter to suppress the operation of the motor generator in the generator mode for a startup transition period of the compressor and a to-stop transition period of the compressor, while the engine is running.

Abstract: In a vehicle air conditioner with an automatic air-conditioning control, when a change operation of a set temperature is not performed by a passenger while air conditioning control is performed based on the set temperature in one region of environment condition, it is determined that the one region is a region corresponding to a passenger's preference. Accordingly, even if the change operation of the set temperature is not performed, when the region is stored once for the air conditioning control, the region is used as a learned region. Further, when the change operation of the set temperature is performed in an another region, a correction of the set temperature of the learned region is restricted. Thus, it can restrict the set temperature of a region, which is satisfied by the passenger from being changed.

Abstract: An air conditioning module is constructed to include all the necessary components for an air conditioning system within a single housing, with the housing having a supply air opening and a return air opening. The various components within the housing are so situated that the return air opening is relatively large in its lateral extension across the roof of a bus such that a single module can accommodate various configurations and locations of the supply air and return air openings in the roof of a bus.

Abstract: Cooling devices are provided to reduce a person's temperature by evaporative, convective, and/or conductive cooling. One such device maximizes evaporative cooling by aiding the flow of air to the person and the removal of vapor-laden air from the person. An upper sheet and a base sheet are adhered to define numerous elongated, parallel, inflatable cooling chambers separated by flat connecting membranes. Ventilating cross-members interconnect the cooling chambers. Air enters the chambers through an inlet, exits the chambers toward the person through air permeable regions of the base sheet. Air heated by the person's body exits the device upward through evaporation openings in the connecting membranes. The foregoing device, or different variations thereof, may be modified for use in conductive cooling by adding an absorbent sheet beneath the base sheet, or substituting the absorbent sheet for the base sheet itself.

Abstract: A compact rooftop air conditioning unit for a vehicle, said unit having an evaporator coil located in front of a condenser coil. At least one cylindrical blower is mounted adjacent the evaporator coil and is arranged to provide conditioned the blower and a condensate pump is secured to the shaft for pumping condensate generated by the evaporator coil back over the condenser coil. An electrically driven compressor is housed within the unit and is arranged so that no refrigerant lines pass outside of the unit. An inverter is also housed within the unit and provides a regulated input to the compressor and the blower drive motor. The heat exchanger coils are mounted in the form of two tube sheets take over the function of a housing, with the drip pan closing the bottom and the unit lid closing the top to form the completed unit.

Abstract: A compact rooftop air conditioning unit for a vehicle, such as a bus, having an evaporator coil located in front of a condenser coil. A plurality of cylindrical blowers are mounted adjacent the evaporator coil and arranged to provide conditioned supply air to the interior of the vehicle. A single electric motor is connected to an elongated drive shaft which drives the blowers. A condensate pump is included for pumping condensate generated by the evaporator coil back over the condenser coil. An electrically driven compressor is housed within the unit and is arranged so that no refrigerant lines pass outside of the unit. An inverter is also housed within the unit and provides a regulated input to the compressor and the blower drive motor.

Abstract: Method for producing a galvanized steel drain pan of rectangular or square configuration for use in refrigerators, freezers, and air conditioners to collect condensate water, the method includes the steps of: cutting a blank galvanized steel plate to the desired size; folding sides portions of the blank to a degree of 60 to 90 to form side portions of the drain pan; corrugating the corners formed by the side portions; and installing a drain fitting along with a pipe to drain the condensate water from the drain pan. Also disclosed is the drain pan made by the method.

Abstract: A compact, inexpensive pipe freezer with defrost cycle for forming a frozen ice plug in a section of pipe to be repaired, and, after the repair operation has been completed, defrosting the pipe freezer's evaporator and freeze heads so that the pipe freezer can be removed from the frozen pipe without damaging the pipe freezer.

Abstract: A cooling device is constructed by a water impermeable member defining a water passage, the water impermeable member being provided with a vapor permeable member which is permeable to water vapor and impermeable to water, and has the form of a mesh and made of a material having water repellency. The cooling device has a long-life operation while preventing wear-out of the vapor permeable member. Further, optimally setting the size of an opening of the mesh member enables to securely dissipate water vapor outside of the cooling device through the vapor permeable member while efficiently suppressing water leak.

Abstract: A heat pump air conditioning system having an outside heat exchanger which is disposed in an engine compartment of a vehicle is provided. The outside heat exchanger consists of a first outside heat exchanger disposed forward of an engine and a second outside heat exchanger disposed near the engine except the front, especially rearward of the engine. When heating the passenger compartment, the second outside heat exchanger acts as a heat absorber, utilizing the heat of the engine, and effectively heating the interior.

Abstract: An aqua-ammonia chiller apparatus is modified to include a heater function by providing a refrigerant by-pass for directing refrigerant to a heat exchanger capable of selectively functioning as a condenser during a heating mode or an evaporation during a cooling mode without passing through the apparatus condenser during the heating mode.

Abstract: Disclosed is a refrigerator incorporating a condenser functioning as a backcover. The condenser is provided in one portion of the outer periphery of a machine room in a lower portion of the refrigerator while the machine is closed in other portions of the outer periphery so that air flow to/from the machine room is enabled only through the condenser to enhance cooling efficient and thus condensing efficient.

Abstract: The invention concerns a method for generating energy, which consists in conveying to an air separation apparatus (5) air from a compressor (1) coupled to an expansion machine (3). A nitrogen-enriched gaseous flow (11) containing between 3 and 18% of oxygen is conveyed to a combustion chamber (19) with a combustible flow (17) and the combustion gases (33) are expanded in the expansion machine. Optionally air from an auxiliary compressor (21) can be conveyed to the combustion chamber.

Abstract: Systems and methods are disclosed for the power efficient production of high-pressure gaseous oxygen product. In a preferred embodiment, a liquid oxygen stream is pumped to a low to medium pressure and warmed within a first heat exchanger such as a brazed aluminum plate fin heat exchanger. The liquid oxygen stream is then pumped to a further pressure and then vaporized in a second heat exchanger to produce a high-pressure gaseous oxygen stream. In an embodiment, a high-pressure air stream may be utilized in the second heat exchanger for vaporizing the oxygen stream and cooling the air stream. The air stream may be utilized as a feed for the cryogenic air unit. A portion of the air stream at a medium pressure may be utilized in the first heat exchanger. A portion of the air stream may also be expanded to recover energy.

Abstract: The back portion of an omega-back earring is formed by investment casting and then heat-treated to have spring gold characteristics. A rear surface of the ornamental front portion of the earring includes a depression to present a concave profile which is complementary to the convex profile of the pushing part of the rear portion of the earring. In a non-identical mirror-image pair of earrings, a design element such as a small precious stone is provided on only one of the earring pair, at an inconspicuous spot, to aid the wearer in distinguishing the right earring from the left earring.

Abstract: A jewelry finding is provided as a neck accessory that enables a flexible bracelet to be worn as a necklace. Locket clasps are provided at the ends of the neck accessory to provide secure interconnection of the bracelet clasp ends with the neck accessory, while at the same time enclosing and obscuring from view the connection hardware. According to an alternate embodiment, a universal approach is implemented that uses flexible loops to modify clasp ends of most any flexible bracelet to be connectible to fastening posts in the locket clasps of the neck accessory.

Abstract: Apparatus (26) and a method for forming heated glass sheets in a heated chamber (22) of a housing (20) includes an upper mold support assembly (28) for supporting an upper mold (38) within the heated chamber for cyclical vertical movement between upper and lower positions. A lower mold shuttle (50) supports a lower mold (36) for movement between an idle position horizontally spaced from the upper mold and a use position below the lower mold. The apparatus also includes a lower mold support assembly (60) to which the lower mold is transferred from the lower mold shuttle (50) to provide support thereof while permitting horizontal alignment with the upper mold upon each cycle of downward movement to form a heated glass sheet between the molds. The lower mold shuttle (50) is supported by vertically movable rollers (70) to provide the transfer between the lower mold shuttle and the lower mold support assembly (60).

Abstract: A glass material (4) is placed in a forming die including a pair of upper and lower dies (1, 2) and a control member (3) for controlling the space between the upper and the lower die, and then heated, softened, and molded by pressure into a glass substrate in the shape of a parallel plate. The amount of thermal contraction of the control member is smaller than that of the glass material. Therefore, the glass substrate is released from the die when cooled after molding. The present invention can provide a glass substrate that is excellent in smoothness and form accuracy of the surface, and that is suitable for recording media such as magnetic disks that are inexpensive and suitable for mass production.

Abstract: The present invention provides a method of preparing preforms for optical fibers. The invention allows one to remove or significantly reduce undesirable refractive index variations in the central portion of the optical fibers. The method of preparing the preform having a central duct includes the steps of a first collapsing step, an etching step and a second collapsing step. The first collapsing step reduces the size of the central duct without closing the central duct by heating the preform at a first preform collapsing temperature. A portion of the last deposited layer of the core glass layers is etched by flowing an etchant gas through the central duct at a lower temperature than the preform collapsing temperature. The preform is finally collapsed at a second collapsing temperature to close the central duct of the preform and form a solid rod.

Abstract: The present invention relates to a method for producing a preform, which is substantially free of OH impurities, for an optical fiber, wherein one or more quartz layers, which may or may not be doped, are deposited on the internal surface of a quartz glass support tube, in which method a furnace is moved axially with respect to the support tube, and after the quartz layers have been deposited the support tube is contracted into a bar-shaped preform while being heated, wherein the furnace comprises an electrical resistance furnace, in which furnace the support tube is rotated, with the space between the rotating support tube and the furnace being washed with an inert gas.

Abstract: A lock that is tamper resistant and includes a lock member. Two tubes are disposed on the lock member. Each of the two tubes extend generally outwardly therefrom and each define a bore therethrough. The lock includes a closure member which has two shafts. The two shafts are inserted through the two tubes and detachable within the lock member when the lock is an installed configuration. A locking mechanism detachably locks the closure member to the lock member when the lock is in the installed configuration wherein the two tubes substantially cover the two shafts.