The air intake system of a two-bank internal-combustion engine has one resonance receptacle for each cylinder bank and an additional receptacle in the respective center. Via suction pipes, the resonance receptacles are connected to the cylinders and are mutually provided with connecting pipes, fresh air entering into one of these connecting pipes. Suction pipe extensions are connected to the other receptacle which partially extend inside the resonance receptacles and are arranged in them at a distance in an alignment with the admission funnels of the suction pipes. The combination of the connecting pipes acting as resonance pipes and the suction pipe extensions acting as swing pipes causes an increase of the mean pressure which raises the torque as well as the performance of the internal-combustion engine.

The present invention relates to an air intake system of a multi-cylindrical two-bank internal-combustion engine, the cylinder of one bank each being connected by suction pipes to a resonance assigned to said bank, and comprising at least one connecting pipe between the resonance receptacles.
The performance of an internal-combustion engine is directly proportional to the product of its displacement and the mean pressure. When an increase of the displacement, which is unfavorable with respect to the amount of exhaust gas and to fuel consumption, is to be avoided, only a targeted increase of the mean pressure remains as a means to increase the performance. As a result, the torque of the internal-combustion engine is also increased because it is a direct result of the above-mentioned product.
From German Patent Document DE-34 24 433 A1, an air intake system of the initially-described type is known which has two resonance receptacles. These resonance receptacles are connected with one another by two resonance pipes which can be shut off and into which the supplied fresh air flows. From the resonance receptacles, individual suction pipes lead to the intake ports of the cylinder heads. As a function of the connection cross-section of the receptacles controlled by throttle valves, the mean pressure and therefore the torque can be increased in a wide rotational speed range.
An object of the present invention is to improve an air intake system of the intially-described type in such a manner that the mean pressure is increased, if possible, in the whole rotational speed range of the internal-combustion engine.
This and other objects are achieved by the present invention which provides an air intake system of a multi-cylinder two-bank internal-combustion engine, the cylinder of one bank each being connected by suction pipes to a resonance receptacle assigned to said bank, comprising: at least one connecting pipe between the resonance, and suction pipe extensions that are respectively assigned to the suction pipes. These suction pipe extensions extend inside the resonance receptacles and are connected to a common receptacle that has a fresh-air inlet.
When, in the case of an internal-combustion engine, in addition to the two-chamber resonance system formed by the resonance receptacles and the connecting pipe, suction pipe extensions are arranged which, in sections, extend in the resonance receptacles, are assigned to the suction pipes and are connected to a common receptacle provided with a fresh-air inlet, this single-chamber ram pipe system formed by the receptacle and the suction pipe extensions acting as ram pipes, supplements the resonance system such that the volumetric efficiency will rise. This means that a larger amount of fresh air is fed to each cylinder, thereby increasing the mean pressure.
In certain embodiments of the invention, the connecting pipe also has a fresh-air inlet whereby the mean pressure is further increased.
The two fresh-air inlets are advantageously combined in a common inlet opening of the receptacle, in certain embodiments of the invention. This inlet opening may be arranged on the end of the receptacle which extends in the longitudinal direction of the cylinder banks approximately in the center between the resonance receptacles. In this case, the connecting pipe is constructed to be divided, the sections of the resonance receptacles extending to the center receptacle. By means of the center inflow and the direction connection of the connecting pipe and of the suction pipe extension to the receptacle distributing the fresh air, this arrangement permits a low-loss uniform flow.
In certain embodiments of the invention, at least one suction pipe extension of each cylinder bank has a throttle valve acting as a shut-off element. In this case, the air intake system acts as a pure resonance system, these suction pipes extensions acting as switchable additional resonance pipes.
Certain embodiments of the invention further increase the mean pressure and optimize the flow conditions and vibration conditions by mutual alignment of the cylindrically constructed sections of the suction pipe extension which are situated in resonance receptacles. In this case, these have a specified distance from the admission funnels of the suction pipes.
Another optimization is achieved in certain embodiments an arrangement of sliding sleeves on the cylindrical sections, in which case the distance from the admission funnels can optionally be bridged. As a result, the charge effect of this air intake system is improved in a wide rotational speed range because of the fact that, in a low to medium rotational speed range, the sliding sleeves close off the annular gap defined by the distance and uncouple the two-chamber resonance system. As a result, only the single-chamber system is connected, in which case the suction pipe length is increased by the amount of the suction pipe extension and the overall volume of the system is reduced. By the opening of the annular gap at higher rotational speeds, the resonance system is connected, and the suction pipe length is shortened and the overall volume is reduced.
For a further improvement of the resonance characteristics, in parallel to the connecting pipe, certain embodiments of the invention provide a second connecting pipe arranged between the resonance receptacles. For the rotational-speed-optimal connection of the connecting pipes, these embodiments are provided with shut-off elements which are to be actuated as a function of the rotational speed.

Air intake system of an internal-combustion engine


An electric machine, includes a rotor, a first radial fan wheel and a second radial fan wheel arranged on opposite sides of the rotor in axial direction, a first cooling air chamber and a second cooling air chamber; a first cooling air path extending in axial direction up to a side of the second radial fan wheel which faces away from the first radial fan wheel and from there leading into the second cooling air chamber, a second cooling air path extending in axial direction up to a side of the first radial fan wheel which faces away from the second radial fan wheel and from there leading into the first cooling air chamber, wherein the first radial fan wheel moves cooling air from the first cooling air chamber along the at least one first cooling air path and the second radial fan wheel moves cooling air from the second cooling air chamber along the at least one second cooling air path.

The invention relates to an electric machine.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
An electric machine can generally be constructed as an electric motor or a generator. The electric machine is for example a three-phase machine, in particular a three-phase asynchronous machine. It has a rotor, which is supported for rotation about a rotation axis, for example within a housing of the electric machine. The rotor preferably interacts with a stationary stator in order to either convert electric energy into a movement of the rotor or vice versa to convert the rotation of the rotor into electric energy.
The heat produced hereby has to be dissipated from the electric machine in order to prevent overheating and eventually temperature-related damage to the electric machine. For this purpose radial fan wheels, for example the first radial fan wheel and the second radial fan wheel are for example arranged on opposing sides of the rotor. The radial fan wheels are preferably operatively connected with the rotor, in particular rigidly. Correspondingly the radial fan wheels can be driven the by the rotor. The radial fan wheels can also be driven in a different manner. By means of the radial fan wheels a cooling air stream through the electric machine is generated, via which the heat generated in the electric machine can be at least partially dissipated.
It would be desirable and advantageous to provide an electric machine, which has advantages compared to known electric machines and in particular enables a more efficient cooling by means of the radial fan wheels.


A device for use in connection with training a dog to retrieve a ball that allows the user to repeatedly launch the ball with a reduced amount of effort while also eliminating the need for the user to physically touch the ball. The device includes a ball receiving portion and a handle that extends outwardly therefrom. The handle includes an integrated treat storage compartment and a dispenser configured to deposit treats onto the ball receiving portion. The user launches the ball and then dispenses a treat onto the ball receiving portion so that upon returning with the ball, the dog can deposit the ball onto the ball receiving portion in exchange for the treat.

The present invention relates generally to devices for use in connection with training and exercising dogs. More specifically, the present invention is directed to a device that is configured to dispense treats to a pet in exchange for the pet depositing a retrieved object, such as a ball. In addition, the device allows a user to launch a retrieved ball without requiring a user to physically handle the ball.
It is well known in the art that many dogs are natural retrievers and that they enjoy repeatedly retrieving or fetching objects such as sticks or balls. In addition, many dog owners enjoy the opportunity to bond and/or play with their dog that is presented through the game of fetch. One of the difficulties, however, is that in playing fetch with a dog, the stick or ball must be repeatedly thrown at relatively long distances for prolonged periods of time. As a result of the repeated throwing, often the dog owner's back and arm tire before the animal is ready to rest. Additionally, another drawback to playing the game of fetch with a dog is the need to physically pick up and throw the ball using your hands. Typically, after a few throws, the ball is covered with dog saliva and a layer of accumulated dirt and debris, which can be distasteful and unhealthy to touch. Finally, it is often difficult to persuade the dog to drop the ball once it has been retrieved. In order to get the ball back from the dog, the owner must often place their hand into the dog's mouth and extract the ball, all the while enduring the ensuing wrestling match or worse, the risk of being accidentally bitten by the dog.
To assist in throwing the ball long distances with a minimum amount of exerted effort, some individuals have resorted to using bats, tennis rackets or other catapult devices for launching the ball great distances. While such devices may be helpful in reducing the fatigue associated with repeated throwing of the ball, these devices do not address the issue of holding the ball once it has become wet and dirty nor do they assist in persuading the dog to give up the ball after retrieving it.
In general, the ability to get the dog to drop the ball after it has been retrieved relates to proper training of the dog. When training animals, such as dogs, it is beneficial for trainers to reinforce specific behaviors and acts performed by the animal by offering positive reinforcement. For positive reinforcement to be most effective, it is necessary to provide such reward in an immediate and non-distracting manner. The immediacy is necessary in that it serves to maximize the training effect because an animal's ability to associate reward with specific acts is limited to a very short period of time (approximately three (3) seconds). This ability quickly deteriorates with the passage of time and can be adversely affected by distracting movements or sounds produced by the trainer obtaining and delivering the reward.
In this regard, several known methods of providing positive reinforcement are currently employed by trainers. For example, the reward can be carried in one's hand, one's pocket, a plastic or paper bag or a bait bag. Each of these methods, however, adversely affects the act/reward association time that is so crucial to effective training. Carrying rewards in the trainer's hand is distracting for the trainer and the animal in that the animal's attention is directed at the hand holding the reward. The difficulty with carrying rewards in one's pocket or a bag is that rewarding an animal requires the trainer to dig into his pocket, unzip or open the containment device causing harmful delay in the act/reward associate time thereby causing the animal to associate his reward with a noise such as a zipper opening, or Velcro® being pulled away or the resulting sound of a plastic or paper bag. Additionally, training an animal utilizing the disposable pocket requires the trainer to consciously count the quantity of rewards retrieved from the pocket and return any unwanted rewards before rewarding the animal, again increasing the act/reward association time. The disposable pocket may also be prone to falling off during prolonged training as the adhesive may lose its grip, or be prone to being knocked off by an exuberant animal, or inclement training conditions such as brush, high grass during field exercises. Likewise, devices such as bait bag with clip may also be prone to falling off the trainer when the trainer bends down and also in many of the same instances where the disposable pocket is likely to fall off.
Accordingly, there is a need for a device that allows a user to pick up and throw a ball for a dog to fetch, while eliminating the need for the user to touch the ball with their hands. There is a further need for a device that enhances the user's ability to throw a ball for extended periods of time without tiring while also reducing or eliminating the need to physically touch the ball. There is still a further need for a device that facilitates proper training of the dog in a manner that positively reinforces the behavior of releasing the ball once it has been retrieved. There is yet a further need for a device that facilitates handling and throwing a ball repeatedly while also providing storage for dog treats and the ability to provide positive reinforcement to the dog for releasing the ball all within a convenient and easy to use package.


A method for enrolling a user in a speech recognition system, without requiring reading, comprises the steps of: generating an audio user interface having an audible output and an audio input; audibly playing a text phrase; audibly prompting the user to speak the played phrase; repeating the steps of audibly prompting the user not to speak, audibly playing the phrase and audibly prompting the user to speak, for a plurality of further phrases; and, processing enrollment of the user based on the audibly prompted and subsequently spoken phrases. A graphical user interface can also be generated for: displaying text corresponding to the phrases and to the audible prompts; displaying a plurality of icons for user activation; and, selectively distinguishing different ones of the icons at different times by at least one of: color; shape; and, animation.

1. Field of the Invention
This invention relates generally to the field of speech recognition systems, and in particular, to speech recognition enrollment for non-readers and displayless devices.
2. Description of Related Art
Users of speech recognition programs need to enroll, that is provide a sample for processing by the recognition system, in order to utilize the speech recognition system with maximum accuracy. When a user can read aloud fluently, it is easy to collect such a sample. When the user cannot read fluently for any reason, or when the speech system does not provide for a display device, collecting such a sample has thus far not been practical. Speech recognition systems can be implemented in connection with telephone and centralized dictation systems, which need not have display monitors as part of the equipment.
Recent years have brought significant improvements to speech recognition software. Speech recognition software, also referred to as a speech recognition engine, constructs text from the acoustic signal of a user""s speech, either for purposes of dictation or command and control. Current systems sometimes allow users to speak to the system using a speaker-independent model to allow users to begin working with the software as quickly as possible. However, recognition accuracy is best when a user enrolls with the system.
During normal enrollment, the system presents text to the user, and records the user""s speech while the user reads the text. This approach works well provided that the user can read fluently. When the user is not fluent in the language for which the user is enrolling, this approach will not work.
There are many reasons why a user might be a less than fluent. The following list is exemplary: the user can be a child who is just beginning to read; the user can be a child or adult having one or more learning disabilities that make reading unfamiliar material difficult; the user can be a user who speaks fluently, but has trouble reading fluently; the user can be enrolling in a system designed to teach the user a second language; and, the user can be enrolling in a system using a device that has no display, so there is nothing to read.
There is a long-felt need to provide speech recognition enrollment for non-readers and for speech systems without display devices.
An enrollment system must have certain properties in addition to those in systems for fluent readers in order to support users who are non-readers and users without access to display devices. In accordance with the inventive arrangements, the most important additional property is an ability to read the text to the user before expecting the user to read the text. This can be accomplished by using text-to-speech (TTS) tuned to ensure that the audible output faithfully produces the words with the correct pronunciation for the text, or by using recorded audio. Given adequate system resources, recorded audio is presently preferred as sounding more natural, but in systems with limited resources, for example handheld devices in a client-server system, TTS can be a better choice.
Thus, the long-felt need of the prior art is satisfied by providing the enrollment text to the user via an audio channel, with adjustments to the standard user interface to provide for an easy-to-understand sequence of events.
A method for enrolling a user in a speech recognition system without requiring reading, in accordance with the inventive arrangements, comprises the steps of: generating an audio user interface having an audible output and an audio input; audibly playing a text phrase; audibly prompting the user to speak the played text phrase; repeating the steps of audibly playing the text phrase and audibly prompting the user to speak, for a plurality of further text phrases; and, processing enrollment of the user based on the audibly prompted and subsequently spoken text phrases.
The method can further comprise the step of audibly playing a further one of the plurality of further text phrases only if the spoken phrase was received.
The method can further comprise the step of repeating the steps of audibly playing the text phrase and audibly prompting the user to speak for the most recently played text phrase if the spoken text phrase was not received.
The method can further comprise the step of audibly prompting the user, prior to the audibly playing step, not to speak while the text phrase is played.
The method can further comprise the step of generating audible user-progress notifications during the course of the enrollment.
The method can further comprise the step of audibly prompting the user in a first voice and playing said text phrases in a second voice.
The method can comprise the step of audibly playing at least some of the text phrases from recorded audio, audibly playing at least some of the text phrases with a text-to-speech engine, or both. Similarly, the user can be audibly prompted from recorded audio, with a text-to-speech engine, or both.
The method can further comprise the steps of: generating a graphical user interface concurrently with the step of generating the audio user interface; and, displaying text corresponding to the text phrases and to the audible prompts.
The method can further comprise the steps of: displaying a plurality of icons for user activation; and, selectively distinguishing different ones of the plurality of icons at different times by at least one of: color; shape; and, animation.
A computer apparatus programmed with a set of instructions stored in a fixed medium, for enrolling a user in a speech recognition system without requiring reading, in accordance with the inventive arrangements, comprises: means for generating an audio user interface having an audible output and an audio input; means for audibly playing a text phrase; and, means for audibly prompting the user to speak the played text phrase.
The apparatus can further comprise means for generating audible user-progress notifications during the course of the enrollment.
The means for audibly playing the text phrases can comprise means for playing back prerecorded audio, a text-to-speech engine, or both.
The apparatus can further comprise: means for generating a graphical user interface concurrently with the audio user interface; and, means for displaying text corresponding to the text phrases and to the audible prompts.
The apparatus can also further comprise: means for displaying a plurality of icons for user activation; and, means for selectively distinguishing different ones of the plurality of icons at different times by at least one of: color; shape; and, animation.

Speech recognition enrollment for non-readers and displayless devices

International Business Machines Corporation


According to the invention, an IP core is clocked during a debugging operation by switching from the clock used for testing the device under test to a clock oscillator or any other free-running clock source.

The present invention relates to a system and a method of clocking an IP core during a debugging operation.
In the design of integrated circuits, there is an increasing demand for emulation and verification tools. Hardware-based verification solutions have been around for years in two different embodiments: accelerators and emulators. Useful tools in emulation systems are so-called IP-Xpress kits which are emulation-ready kits for concurrent hardware and software verification of processor-based systems. Such IP-Xpress kits use microprocessor or DSP chips, mounted onto a printed-circuit-board to provide the functionality of the device to be connected to a design mapped into the emulator, and the kits consist of a board and HDL-wrapper files.
All processor-type IP cores require some external clock source. Hence, one or more clock signals are provided to the IP-Xpress boards. The clocks are provided either directly from the internal clock generators of the emulator or they may be driven from the design loaded onto the emulator.
Another way of providing clock to an IP core is by using a clock oscillator mounted onto the IP-Xpress board. In this case any frequency can be applied, i.e. there are no maximum clock frequency constraints due to the emulation system.
A key advantage of an IP-Xpress kit is to provide a fast running system verification environment in which application software is running on the IP core and this stimulating the design mapped to the emulator. In case of faulty system behaviour, the cause for this could either be in the application software or in the design (provided the IP core is functioning correctly). In order to identify the erroneous component of the system both the application software as well as the design has to be debugged. This can be done most conveniently when the hardware and software are stopped synchronously. On the one hand, this gives a good correlation between the design's status and the actual software execution, and on the other hand it enables to interrogate all resources of the design mapped onto the emulator system. This may mean, however, that the emulator clocks are stopped. In case the IP core is clocked by a clock generated by the emulator system, this would mean that the IP core is not clocked anymore. Hence, the software debugger would not necessarily work and as a result the resources of the software execution were not visible and a full system debugging would not be possible.

This patent is subject to a terminal disclaimer.

System and method of clocking an IP core during a debugging operation


A zoom lens having two units of lens components including from the object side a positive optical unit and a negative optical unit. The zoom lens satisfies the following relationship ##EQU1## where eW is the principal point separation of the zoom lens when said zoom lens operates at a wide angle position and eT is the principal point separation of the zoom lens when said zoom lens operates at the telephoto position.

1. Field of the Invention
This invention relates to compact zoom lenses. Although the invention has general application, it is particularly usable in still photographic cameras.
2. Background Art
U.S. Pat. No. 5,270,867 to Lee R. Estelle, issued Dec. 14, 1993, described zoom lenses (also called zoom lens systems) having two units of lens components--a positive front unit and a negative rear unit. The disclosed zoom lenses utilize only three or four lens components and still achieve very good aberration correction for zoom ranges 1:2 and aperture ratios of f/8 to f/11.
U.S. Pat. No. 4,936,661 to E. I. Betensky et al., issued Jun. 26, 1990, described a zoom lens with a short back focal length and having, from front to rear, negative, positive and negative optical units. The negative unit closest to the image is movable during zooming to provide a majority of the change in focal length. In some of the examples, the front two units move as a single optical group during zooming, and in others they move relative to each other during zooming. These lenses have a short back focal length which makes them particularly useful as zoom objectives in "viewfinder" (non-SLR) cameras.
Both of the above-mentioned patent applications disclose well corrected 2.times. zoom lenses. However, there is an increasing need to provide consumers with a well corrected zoom lens comprised of only three to four lens elements which has an expanded zoom range such as 3.times. or higher. In addition, many zoom lenses of the type described above utilize aspheric surfaces. These aspheric surfaces are generally sensitive to decentration and when decentered, they usually produce image plane tilt. Thus, there is also a need for zoom lens systems with an expanded zoom range which have reduced aspheric decenter sensitivity.


An apparatus for manufacturing solder balls including a tundish, a vibrator, a cooling liquid tank an inactive atmospheric chamber, a molten metal receiving tray, a ball collecting barrel, and a cooling liquid reservoir. The tundish has orifices at its bottom. The vibrator is immersed in the molten metal of the tundish and generates vibrations. The cooling liquid tank is situated under the tundish and is provided with a cooling liquid heater at its upper and middle outer surface, a cooling liquid cooler at its lower outer surface, and a cooling liquid discharge conduit at its top. The inactive atmospheric chamber is interposed between the bottom of the tundish and the op surface of the cooling liquid. The molten metal receiving tray is seated on a portion of the inactive atmospheric chamber and is horizontally movable. The ball collecting barrel is positioned under the cooling liquid tank and is provided with a cut-off valve at its top, a ball removing valve at its bottom, and a cooling liquid supply conduit at it s upper portion. The cooling liquid reservoir is situated under the ball collecting barrel, is provided with a ball collecting sieve at its inlet and is connected with the cooling liquid discharge conduit and the cooling liquid supply conduit.

1. Field of the Invention
The present invention generally relates to a method and apparatus for manufacturing solder balls and, more particularly, to a method and apparatus for manufacturing solder balls for BGA (Ball Grid Array) used recently for electronic packaging.
2. Description of the Related Art
As is well known to those skilled in the art, conventional methods for manufacturing tiny metal balls may be classified into three types: a centrifugal spraying type method, a gas-related type method and a method wherein a metal piece having a uniform weight is molten and forms many balls in liquid and the balls are solidified again. However, with the centrifugal spraying type method and the gas-related type method, ball size is not uniform due to their manufacturing characteristics. Also, a very large apparatus is required for solidifying the balls in gas because the balls are greatly accelerated in the manufacturing process. On the other hand, according to the method wherein a metal piece having a uniform weight is molten and forms many balls in liquid and the balls are solidified again, many processes are required prior to the solidification because metal pieces having uniform weights must be made, thus increasing manufacturing cost. In brief, the conventional methods have low gaining or yield rates and are not economical.
There is another method wherein molten metal flows downward through a small orifice. This method uses a natural phenomenon in which liquid in a fine flow is in an unstable state due to boundary surface tension and the liquid is easily cut and forms many droplets by slight waves on a flowing surface. Lord Rayleigh analyzed this phenomenon and explained that the wavelength of the most unstable wave is about 1.9 times as large as the diameter of the orifice in an article xe2x80x9cOn the Instability of Jetsxe2x80x9d, London Mathematical Society, 1878. Accordingly, the diameters of the generated droplets have a normal distribution centering at the diameter about 1.9 times as large as the diameter of the orifice. In such a case, when a vibration having a uniform frequency is applied to the liquid, waves having a uniform periodic time are generated on the surface of the liquid passing through the orifice and the waves are cut into fractions having a uniform size, thereby forming many metal balls.
Such a technique using the natural phenomenon is disclosed in xe2x80x9cInkjet Printer of IBM, J, Resent Developmentxe2x80x9d published in 1974, the method of vibrating a disc in molten metal of U.S. Pat. No. 5,266,098 and the method of applying vibrations from the exterior of liquid to the liquid using a speaker of xe2x80x9cPower and Powder metallurgyxe2x80x9d, Vol. 38, No. 6 published in Japan in 1991. However, this method requires a large apparatus because small droplets are easily solidified in the atmosphere, but large droplets need a long falling distance so as to be solidified, may not regulate the size of balls and reduces a gaining rate.
In order to overcome this defect, the method of solidifying droplets using cooling liquid is proposed in xe2x80x9cThe International Journal of Power Metallurgyxe2x80x9d, Vol. 32 published in 1996. However, according to this method, since molten metal is boiled at the surface of a droplet upon a droplet falling into cooling liquid, the shape of the ball is determined in accordance with the boundary surface tension and the size of the molten metal, thus deteriorating the surface quality and the degree of sphericity of ball.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art and an object of the present invention is to provide a method and apparatus for manufacturing solder balls, reducing manufacturing cost due to their simple processes and increasing a production yield or gaining rate due to the uniform size of balls.
In order to accomplish the above object, the present invention provides a method of manufacturing solder balls comprising the step of dividing molten metal into droplets of a uniform size by applying vibrations to the molten metal stream and the step of sphering the droplets by dropping the droplets into cooling liquid that has a temperature gradient ranging from a temperature higher than a melting point of the metal to a normal temperature.
According to another embodiment of the present invention, the cooling liquid may have a boiling point higher than a melting point of the metal, a relatively low density and a relatively low coefficient of viscosity and is not easily reacted with the metal at a normal temperature.
In addition, the present invention provides an apparatus for manufacturing solder balls, comprising a tundish having one or more orifices at its bottom and containing molten metal controllable in its level, a vibrator being immersed in the molten metal of the tundish and generating vibrations, a cooling liquid tank being situated under the tundish and being provided with a cooling liquid heater at its upper and middle outer surface, a cooling liquid cooler at its lower outer surface and a cooling liquid discharge conduit at its top, an inactive atmospheric chamber being interposed between the bottom of the tundish and the top surface of the molten metal, a molten metal receiving tray being seated on a portion of the inactive atmospheric chamber and being horizontally movable, a ball colleting barrel being positioned under the cooling liquid tank and being provided with a cutoff valve at its top, a ball removing valve at its bottom and a cooling liquid supply conduit at its upper portion, and a cooling liquid reservoir being situated under the ball collecting barrel, being provided with a ball collecting sieve at its inlet and being connected with the cooling liquid discharge conduit and the cooling liquid supply conduit.
According to another embodiment, the orifice may be configured to be diminished from its top to its bottom so as to transmit vibrations generated by said vibrator to the stream flowing through the orifice.

Apparatus for manufacturing solder balls


A scanning device for a magnetic tape recording and playback equipment of the oblique track type has a drive shaft (9) for a rotary head wheel (4) mounted in a duplex ball bearing (10) centered on the orbit plane of the magnetic heads which revolve on the circumference of the head wheel between the two halves of a tape-guiding drum. A support bearing (19) is affixed in the bottom of a housing (17) which houses the drive motor and is held in a downward extending socket at the bottom of the lower half of the drum. The housing can be tilt-shifted slightly for shifting the support bearing and then held, by three screws accessible from below, in the correct position for aligning the orbit of the magnetic heads in the gap between the two halves of the drum.

Such a scanning device is known from, for example, German patent document 26 09 335 C2. That device has an axial-pressure bearing with plane ball-guiding surfaces between a shell which houses that shaft bearing which is nearer to the head wheel disk, and an element for axially fixing and radially adjusting the shell. Three adjusting elements are distributed around the periphery of the tape-guiding drum, of which at least one adjusting element is provided with a plug that is longitudinally shiftable by means of a threaded pin which is beveled at one end and cooperates with a phase of the shell.
U.S. Pat. No. 4,641,214 discloses a rotary head device in which a shaft is clamped between two fixed and coaxially disposed drums. A rotary body for holding the magnetic heads is mounted on the shaft by means of two ball bearings spaced apart from each other. Both of the above-mentioned devices require ball bearings of the highest precision. In order to limit the play between the inner and outer ring of a ball bearing, it is known to cause the inner ring to bear against the outer ring by means of a limited spring effect provided on the inner ring. In the case of two ball bearings disposed at a certain distance from each other, this effect is obtained by providing that respective inner rings of both ball bearings are longitudinally shiftable on the shaft, while along each of the inner rings a compression spring is provided to provide the desired bearing race bias force. There is a disadvantage, however, that thermally caused changes or wear of the ball races produce height fluctuations of the magnetic head orbit.
It is further known from U.S. Pat. No. 4,603,359 to provide a rotary head device with a fixed lower drum and a rotary upper drum which carries the rotating magnetic heads. In parallel surfaces of the lower and upper drum, ring-shaped grooves or traces are provided for seating an axial ball bearing. This known head device is subject to radial shock and is not suited for scanning oblique tracks which are only a few microns wide.

Scanning device for magnetic tape with special bearing arrangement for scanner shaft


A multiple-disc clutch pack. The clutch pack comprises a plurality of porous metal plates mounted concentrically and each having a first and a second surface with at least one of the surfaces impregnated with a magneto-rheological substance. A plurality of grooves is defined on at least one of the surfaces of at least one of the plates.

The invention relates generally to the field of multiple-disc clutch packs, specifically clutch packs utilizing Magneto-rheological (MR) and Electro-Rheological (ER) substances.
ER and MR fluids and powders are substances that rely on a magnetic capable media compounded in a way that allows the substance to change form from a liquid or powder state to a rigid, solid state. These materials comprise micron-sized, magnetizable particles called fines, suspended in oil or other media. ER and MR powders consist solely of unsuspended magnetizable particles.
ER and MR fluids are similar in their operation. The main difference is that ER fluids are responsive to an electric field and MR fluids are reactive to a magnetic field. However, MR fluids do have some advantages over ER fluids.
In their liquid form, ER and MR fluids have a viscosity and consistency much like common motor oil. However, when an electric charge or magnetic field is applied, the fluids change form, becoming rigid and able to bond surfaces together. This rigid bonding mechanism results from a dipole moment introduced on the magnetic particles in the fluid from the electric charge or magnetic field. The particles form chains, aligning parallel to the electric charge or magnetic field. The strength of the bonding mechanism depends on the strength of the charge or field applied to the fluid and the size of the particles. The change in viscosity of the fluid takes place in a few milliseconds. ER and MR powders operate in the same manner, changing from a powder to a rigid form. MR fluids typically exhibit much stronger yield strengths than do ER fluids. MR fluids are also more resistant to temperature changes and have a high tolerance to impurities such as water. MR fluids can also be activated using a much lower voltage power supply. ER fluids require high voltage (near 5,000 volts) to operate. For purposes of the present disclosure, discussion herein of the terms xe2x80x9cER and/or MR fluidsxe2x80x9d is also meant to refer to equivalent ER or MR substances, such as powders.
ER and MR fluids have been examined in the past as a way to xe2x80x9clock upxe2x80x9d or stop a rotating device such as clutch plates. U.S. Pat. No. 2,575,360 describes such an application. The binding properties of the ER or MR fluid could increase the friction between two clutch plates quickly and easily, without having to actually change the axial displacement of the clutch plates. Instead of pressing the clutch plates against each other to bind them together, the ER or MR fluid could simply be activated and the solid form would bind the plates together.
A problem with using ER and MR fluids in this manner is that the fluid disperses during operation of the clutch due to centrifugation of the fluid outwardly and the random non-uniform gap thickness that can exist with flat surface disc clutch plates. When the fluid disperses, the binding properties of the fluid decrease and the clutch will lose its functionality. To solve this problem, it is necessary to replenish the fluid between the clutch plates. Pumping more fluid into the area between the clutch plates though holes in the adjoining shaft can accomplish this, but the plates must be moved apart in order to replenish the layer of fluid between them. This also necessitates a constant high energy power supply on the clutch mechanism to pump the fluid layer between the plates. It is desirable to keep a small volume of the fluid layer in place at all times, with the assistance of a residual low energy power supply, so that operation can be instantaneous, rather than having to replenish the fluid layer to maintain the functionality of the clutch pack. Or, in the alternative, it is desirable to have a mechanism to replenish the fluid layer without axially moving the plates.
In one embodiment of the present invention, a multiple-disc clutch pack is provided. The clutch pack comprises a plurality of porous metal plates mounted concentrically and each having a first and a second surface with at least one of the surfaces impregnated with a magneto-rheological substance. A plurality of grooves is defined on at least one of the surfaces of at least one of the plates.
In a second embodiment of the present invention, a multiple-disc clutch pack is provided. The clutch pack comprises a plurality of porous metal plates mounted concentrically and each having a first and a second surface with at least one of the surfaces impregnated with an electro-rheological substance. A plurality of grooves is defined on at least one of the surfaces of at least one of the plates.
In a third embodiment of the present invention, a multiple-disc clutch pack is provided. The clutch pack comprises at least one first porous metal plate having at least one substantially flat surface and at least one surface impregnated with a magneto-rheological substance. The invention further comprises at least one second porous metal plate having at least one waved surface and at least one surface impregnated with a magneto-rheological substance. The first and second plates are mounted concentrically such that the flat surface of the first plate faces the waved surface of the second plate.
In a fourth embodiment of the present invention, a multiple-disc clutch pack is provided. The clutch pack comprises at least one first porous metal plate having at least one substantially flat surface and at least one surface impregnated with an electro-rheological substance. The invention further comprises at least one second porous metal plate having at least one waved surface and at least one surface impregnated with a magneto-rheological substance. The first and second plates are mounted concentrically such that the flat surface of the first plate faces the waved surface of the second plate.
In a fifth embodiment of the present invention, a method for improving the functionality of a magneto-rheological substance in a multiple-disc clutch pack is provided comprising the steps of providing at least one first porous metal plate, providing at least one second porous metal plate and defining a plurality of grooves in at least one side of each metal plate. The method further comprises the steps of impregnating at least one side of each plate with a magneto-rheological substance and arranging the plates concentrically such that each grooved side of each plate faces non-grooved side of an adjacent plate.
In a sixth embodiment of the present invention, a method for improving the functionality of a magneto-rheological substance in a multiple-disc clutch pack is provided comprising the steps of providing at least one first porous metal plate with at least one substantially flat surface and impregnating the flat surface with a magneto-rheological substance. The method further comprises the steps of providing at least one second porous metal plate with at least one waved surface and impregnating the waved surface with a magneto-rheological substance and arranging the first and second plates concentrically such that each flat surface of each first plate faces a waved surface of a second plate.
In a seventh embodiment of the present invention, a method for improving the functionality of an electro-rheological substance in a multiple-disc clutch pack is provided comprising the steps of providing at least one first porous metal plate, providing at least one second porous metal plate and defining a plurality of grooves in at least one side of each metal plate. The method further comprises the steps of impregnating at least one side of each plate with an electro-rheological substance and arranging the plates concentrically such that each grooved side of each plate faces a non-grooved side of an adjacent plate.
In an eighth embodiment of the present invention, a method for improving the functionality of an electro-rheological substance in a multiple-disc clutch pack is provided comprising the steps of providing at least one first porous metal plate with at least one substantially flat surface and impregnating the flat surface with an electro-rheological substance. The method further comprises the steps of providing at least one second porous metal plate with at least one waved surface and impregnating the waved surface with an electro-rheological substance and arranging the first and second plates concentrically such that each flat surface of each first plate faces a waved surface of a second plate.

Multiple disc clutch pack having rheological film layer


Method (500) and calculating unit (620) for curve sawing of a block (100) in a cutting direction (S) with at least a first circular saw blade (110). The method (500) comprises determining (501) a radius (R) of the curve sawing, by measuring the curvature of the block (100) in the direction of cutting (S); calculating (502) a vertical inclination angle (β) of the first circular saw blade (110) in a vertical plane (V) relative to the cutting direction (S) in the block (100), based on the determined radius (R) of the curve sawing; inclining (503) the first circular saw blade (110) with the calculated (502) vertical inclination angle (β); and sawing (508) the block (100) in the cutting direction (S) with the inclined (503) first circular saw blade (110) along the determined (501) radius (R) of the curve sawing.

A common way to decompose logs into boards and planks is that in a first stage in a so-called stock-taking saw, cut a rectangular block by cutting off the sides, called back sides of the log. The block that remains to divide in a second step in a second-coming so-called division saw has a rectangular cross section, but is usually more or less curved in the longitudinal direction, depending on the log curve. Curve sawing is therefore a usual manner by sawing recut to decompose the curved block and thus gain advantages as to quality and increased yield, as a result of following the grain of the wood to a greater extent compared to straight sawing. It may be added that curve sawed boards later straightens out when drying.
Curve sawing comprises feeding the curved block past the division saw in a curved path that follows the log's curvature. In some cases, a different curve radii when curve sawing along a log. This is due to a rootstock often is crooked in the root end, but may be straightened in the top end. The division saw may be a single circular saw blade (single blade) or double circular saw blades (double blades or twin blades).
When sawing recut with double blades, or twin blades, these often are conflicting and displaced in the feed direction to permit vertical overlap between the circular saws and a certain safety margin to prevent the saw blades from coming into contact with each other. In some cases the overlying and the underlying saw blade may be parallel to each other in a vertical plane, i.e. lack displacement in the feeding direction in relation to each other. In such case, the rotation of the saw blades may be synchronised with each other so that the saw teeth on each respective the saw blade engage in the gap between the serrations on the opposite saw blade, much like the teethes of a pair of inter acting gears, but without touching each other.
A problem occurring at such tight curve sawing is that the saw cuts into the log becomes oblique and curved due to undesirable geometry. The magnitude of this so-called decomposition error may be 0.2-0.6 mm for the relatively large radius curves that are used today, approximately 40-60 meters. For double blades the situation becomes even worse by saw cuts are broadened and rear-sawing is done. Rear-sawing means that the blade of the circular saw blade's rear part (in the log feed direction) will engage as a result of unwanted side forces that push on the blade, resulting in a wider kerf, or saw cut, in the block than otherwise. This increases chip loss, resulting in a reduced yield.
Furthermore, due to the undesirable side forces that occur on the saw blade, it must be dimensioned to withstand this stress laterally, i.e. to be thicker than otherwise would be necessary. This however increases kerf loss further. In addition, there is also an increased risk of blade deformation or breakage and/or that the saw blade must be replaced more frequently than otherwise which can be costly, not least as the production has to be stopped when the saw is at a standstill due to maintenance.
It may also emerge an increased need to insert a wiper slot in the saw blade, which generates further sawdust and thus lowers the yield further.
A further problem with curve sawing is that the timber often has a stronger curvature than the minimum bending radius possible to comply with a circular saw, resulting in that the grain cannot be followed. Another problem is that the wood may be bent in different directions. In such case, it may not be possible to curve saw the wood so that the grain followed.
It may be concluded that there is a need for improvement to increase yield and reduce kerf loss associated with curve sawing of timber, as well as to increase the quality of sawn timber, especially as economical margins may be strained in the sawmill industry.


A method and apparatus for producing SO.sub.2 -containing gas and cement clinker by splitting waste gypsum and anhydrite, using paper fibers as the reducing agent, and firing the splitting residue with additives. The cement forming additives are formed into a mixture with the anhydrite and the mixture is compacted before the final drying and calcining, whereupon the anhydrite containing mixture is subjected to the splitting reaction and firing to form the clinker.

In the desulfurization of flue gases and in the production of phosphoric acid, a waste gypsum is produced which is a significant problem with respect to disposal. The term "waste gypsum" is here used to describe the solid product which is a residue of the desulfurization of flue gases in power plants and elsewhere or which is produced in phosphoric acid processes and which consists of calcium sulfate and mixtures of calcium sulfate and calcium sulfite or mixtures of these with other residues or calcium sulfite itself as a residue from such processes.
From German Patent DE-C 32 22 721, a process for transforming the waste gypsum to SO.sub.2 -containing gas and cement clinker is known in which the gypsum is first converted to an anhydrite, e.g. by drying and calcination,and the anhydrite is mixed with additives useful in the production of cement clinker. The decomposition is carried out in a rotary furnace or kiln which generates a product gas from the cleavage or splitting of the calcium sulfate or calcium sulfite which is high in SO.sub.2 and carbon dioxide, the solid residue CaO reacting with the additives to form the cement clinker.
In this case, the decomposition of the anhydrite is carried out under reducing conditions and the reducing agent is coke.
For this process to be effective, it is important to insure a high degree of decomposition of the anhydrite and this can also insure that the permissible sulfate concentration in the clinker does not exceed a maximum permissible level. If the sulfate content of the clinker exceeds such maximum, melting occurs during the clinker formation and the clinker cannot then be readily milled to form the cement clinker. As a consequence, the high quality of the clinker depends on a high degree of dissociations of the anhydrite.
This could not always be ensured with earlier processes.

Process and apparatus for producing SO.sub.2 -containing gas and cement clinker from waste gypsum


A filler-containing resin composition containing. component A, which is an ethylene copolymer having (a) a melt flow rate (MFR) of 0.01 to 20 g/10 min.; (b) a density D of not more than 0.935 g/cm.sup.3 ; (c) a single peak of elution volume corresponding to a temperature within a range from 30 to 100.degree. C. with the elution curve satisfying a relationship in which the ratio H/W is not less than 1 when H represents the height of the peak and W represents the width of the elution curve at 1/2 H; and (d) an elution volume Y wherein (1) Y.ltoreq.-4500D+4105 when the density D of the component A is less than 0.91 g/cm.sup.3, but Y.ltoreq.100; or (2) Y.ltoreq.10 when the density D of the component A is not less than 0.91 g/cm.sup.3 ; and. component B, which is a particulate inorganic filler having an average particle size of not more than 10 .mu.m, and a bulk density of 0.1 to 0.7 g/cm.sup.3 ;. is provided which can be readily formed by stretching, and that is advantageously usable for the formation of thin formed bodies having excellent elastic recovery, strength and feeling, and also having very excellent gas-permeability.

1. Field of the Invention
The present invention relates to a filler-containing resin composition that con be very readily for being formed by stretching, and that is advantageously usable for the formation of thin gas-permeable formed bodies which can exhibit excellent elastic recovery, strength and feeling, and very excellent gas-permeability when used as sanitary materials, or the formation of thin gas-permeable formed bodies which involve no smoking or roll staining when worked and are able to exhibit excellent gas-permeability, strength and weathering resistance when applied to outdoor uses. The present invention also relates to an stretched film formed by using such a filler-containing resin composition.
2Description of the Related Art
A known technique lot forming a gas-permeable film having through voids extending continuously through the thickness thereof comprises stretching, either uniaxially or biaxially, an unstretched film or the like formed of a composition containing an olefin-based resin and an inorganic filler. An stretched film formed by using such a composition is applied to various uses. For instance, the stretched film is used as a sanitary material for disposable paper diapers, etc., or as a material for an outdoor-use gas-permeable sheet (such as a protective sheet laid on the inside of roof tiles or outer walls of wooden constructions for the purpose of waterproofing and other weathering performance, or a protective sheet applied at the root, etc., of fruit trees or the like for the purpose of heat insulation, etc).
However, it has been difficult to form a conventional resin composition into a thin formed body because the composition does not have sufficient capability of being formed by orientation, nor does it have sufficient strength.
Although it has been desired that a resin composition be formed into thin forms for the purpose of saving resources, rationalizing production, etc., conventional resin compositions have not been quite able to meet such demands.
A film for disposable paper diapers or the like is required to have certain properties in addition to an adequately small thickness, which include good gas (typically, air or water vapor) permeability, and good hand or feeling. In recent years, it has been required that this kind of product have good fitting properties. In order to assure proper fit, a film used in the product must have elastic recovery.
Paper diapers, which are for absorbing liquids, must have good gas-permeability in order to avoid becoming stuffy. Products which may become stuffy are not welcomed by consumers. Further, consumers have recently come to demand products of higher quality than ever, and paper diapers are desirably capable of being closely fitted on the body as pants-type paper diapers are. In order to assure proper fit of paper diapers, a material capable of freely stretching and contracting (i.e., capable of exhibiting elastic recovery) is required. In addition, such a material must also have better feeling than ever.
Conventional gas-permeable sheets or films for outdoor use have insufficient properties with respect to gas (typically, air) permeability, strength, and the capability of being formed at an adequately small thickness. Furthermore, the conventional product has such insufficient weathering resistance that, when used in summer, the film or sheet deteriorates within one or two months, becoming totally useless. In order to improve weathering performance, the conventional practice includes adding agents for imparting weathering resistance (e.g., an ultraviolet screener, and a light stabilizer). However, this method involves many disadvantages. For instance, smoking may occur during forming, or the chill rolls may be contaminated with bled substances. Further, the thus obtained product may have such poor printability that ink in printed portions may easily come off, or the product may be vulnerable to contamination with dust, etc. Thus, conventional products have insufficient properties to be used as gas-permeable films for outdoor uses.

Filler-containing resin composition and stretched films using same


The present invention is related to a partially overlapped single-carrier crosstalk signal cancellation method and an apparatus using the same. For this purpose, the present invention provides a crosstalk canceller including a pre-processor for frequency down-shifting an input signal, a crosstalk signal cancellation module for canceling the crosstalk signal by dividing the input signal by an interpolation ratio, a post-processor for converting an output of the crosstalk signal cancellation modulation into a passband signal, and an error feedback processor for performing a decimation operation on a residual crosstalk signal and feeding backing the decimated residual crosstalk signal to the crosstalk signal cancellation module. In addition, the present invention provides a crosstalk signal cancellation method for performing interpolation and filtering operations by frequency down-shifting an input signal including a crosstalk signal to a baseband and decimating a residual crosstalk signal by frequency-shifting to an original signal frequency.

(a) Field of the Invention
The present invention relates to a method for canceling a partially overlapped single-carrier crosstalk signal and an apparatus using the same. More particularly, the present invention relates to an apparatus for cancellation of a partially overlapped crosstalk signal generated due to overlapping of a transmit frequency bandwidth of a transmitting apparatus and a receive frequency bandwidth of a receiving apparatus in a mobile communication environment for data transmission, and a method thereof.
(b) Description of the Related Art
The development of communication and network technologies has provided various types of multimedia services such as e-mail, chatting, messengers, games, movies, and music. Particularly, many users require multimedia services through a wireless Internet service since the users can use the wireless Internet service anytime and anywhere.
An increasing demand for the multimedia services requires a higher data transmission speed for multimedia service contents transmission, and the higher data transmission speed can be achieved by increasing spectral efficiency, a data symbol transmission rate, or a signal bandwidth.
However, increase of the symbol rate may not always be feasible in practice due to the limited available bandwidth and complexity in implementation of a mobile communication system. For this reason, the demand for the high speed transmission cannot be solved by simply increasing the data transmission speed.
In a digital subscriber line (DSL) environment, different frequency bands are used for a transmitter (TX) and a receiver (Rx) for duplex operation. For example, the increase of the symbol rate can be achieved without increasing the overall bandwidth by making the Tx and Rx spectra overlap each other in the frequency domain. In this case, a crosstalk signal due to imperfect wire shielding must be suppressed.
Conventionally, an inband data-driven crosstalk canceller (IDXC) scheme is used to cancel the crosstalk signal.
The IDXC scheme processes the crosstalk signal at a Nyquist rate, which can be implemented by using a polyphase structure, and therefore, the IDXC scheme provides reliable performance while being robust against timing and frequency offset. Herein, the Nyquist rate can be used to perform signal transmission without causing inter-symbol interference.
However, when an overlapped bandwidth of the crosstalk signal is smaller than a bandwidth of a Tx signal, a conventional Nyquist rate IDXC uses a sampling frequency much higher than the bandwidth of the overlapped crosstalk, requiring large computational complexity.
FIG. 1 shows that the spectrum of a single-carrier crosstalk signal is formed by the partially overlapped spectra of the Tx and Rx signals.
As shown in FIG. 1, assuming that the Tx and Rx spectra are partially overlapped, a spectrum fe of a crosstalk signal can be represented as given in Equation 1.
                              f          e                =                              f                          C              L                                +                                                    f                                  b                  L                                                                              f                                      b                    L                                                  +                                  f                                      b                    H                                                                                (                                                f                                      C                    H                                                  -                                  f                                      C                    L                                                              )                                                          [                  Equation                                                              1                ]
(where fCL denotes a carrier frequency of a low-band signal in the DSL, fCH denotes a carrier frequency of a high-band signal in the DSL, fbL denotes a symbol rate of the low-band signal, and fbH denotes a symbol rate of the high-band signal).
The bandwidth overlapping together with the use of imperfect wire shielding results in a crosstalk signal in the received signal. In FIG. 1, the region A shows the spectrum of the crosstalk signal formed by the partially overlapped received signals in the frequency domain.
Assume that the Tx signal is pulse-shaped by using a square-root raised cosine filter (SRCF) with a roll-off factor of α. Then, the spectrum of the crosstalk signal is located in the frequency range of Equation 2.
                                          f                          C              H                                -                                                    f                                  b                  H                                            2                                                  (                              1                +                α                            )                                      ≤        f        ≤                              f                          C              L                                +                                                    f                                  b                  L                                            2                                                  (                              1                +                α                            )                                                          [                  Equation                                                              2                ]
In order to measure the amount of the spectral overlapping, a carrier spacing ratio must be defined as given in Equation 3. The spacing ratio ζ represents frequency spacing between the center frequencies of the Tx and Rx signals normalized by the bandwidth of the Tx signal.
                    ζ        ≡                              2                                      (                                                f                                      C                    H                                                  -                                  f                                      C                    L                                                              )                                                          (                                                f                                      b                    L                                                  +                                  f                                      b                    H                                                              )                                                  (                              1                +                α                            )                                                          [                  Equation                                                              3                ]
When the spacing ratio is less than 1 (i.e., ζ<1.0), it implies that the two signals are overlapped in the frequency domain.
The Nyquist rate IDXC is used for crosstalk signal cancellation in data communications, and an interpolation ratio L of a polyphase structure is defined as given in Equation 4.
                    L        ≥                  {                                                                                ⌈                                                                                2                                                                                f                                                              C                                H                                                                                +                                                                                f                                                              b                                H                                                                                (                                                              1                                +                                α                                                            )                                                                                f                                                      b                            L                                                                                ⌉                                        ;                                                                                in                                                                                the                                                                                premises                                                                                ⌈                                                                                2                                                                                f                                                              C                                H                                                                                +                                                                                f                                                              b                                H                                                                                (                                                              1                                +                                α                                                            )                                                                                f                                                      b                            H                                                                                ⌉                                        ;                                                                                in                                                                                the                                                                                central                                                                                office                                                                        .                                              [                  Equation                                                              4                ]
Where ┌x┐ denotes the largest integer less than or equal to x.
When the crosstalk signal has a duration of N symbols and a conventional least mean square (LMS) adaptation algorithm is employed, each L-polyphase sub-canceller requires 4N MACs for filtering and adaptation of N complex-valued coefficients for each symbol duration. Herein, the MAC is a unit for one multiplication and accumulation.
Therefore, the L-polyphase sub-canceller requires a computational complexity of 8LNfbL MACs per second. As an example, assume that a symmetric DSL (SDSL) with a symbol rate of 256 Kbauds and ζ=0.83 is implemented. In this assumption, a conventional Nyquist rate IDXC requires a computational complexity of more than 640×106 MACs for a crosstalk signal with a span of 80 μs microseconds. However, it is difficult to implement such a sub-canceller that performs the computation by using a conventional digital signal processor.

Apparatus and method for cancellation of partially overlapped crosstalk signals

Electronics and Telecommunications Research Institute


Vacuum and other pressure swing adsorption vessels are monitored, and corrective adjustments are made in the pressure equalization and/or repressurization steps in response to imbalances in the temperature profiles of the vessels in order to tune the system. The PSA process is also desirably purge tuned to avoid over purging or under purging of each vessel.

1. Field of the Invention
The invention relates to pressure swing adsorption for gas separation. More particularly, it relates to the tuning of vacuum pressure swing adsorption systems to maintain stable high performance.
2. Description of the Prior Art
Pressure swing adsorption (PSA) processes have been used to separate and purify gases in highly significant applications, such as the separation of air to produce oxygen or nitrogen product gas. Most PSA processes are carried out in multi-bed systems with each bed undergoing the same sequence of steps but in a different phase relationship with other beds in the system. Such processes involve adsorption at an upper pressure level, desorption at a lower pressure level, and repressurization from the lower pressure to the upper pressure. Many PSA processes also employ one or more pressure equalization steps or repressurization steps in which gas is withdrawn from one bed at high pressure and passed, directly or through the use of a surge tank, to another bed initially at lower pressure until the pressures in said beds are equalized. This enables some compression energy to be saved, and generally also enhances the overall recovery of product gas, e.g., oxygen, in the process,
In vacuum pressure swing adsorption (VPSA) processes, the lower desorption pressure is a sub-atmospheric, i.e., vacuum, desorption pressure. In a desirable VPSA processing sequence for air separation, the following sequence of operating steps is carried out, on a cyclic basis, in one or more adsorbent beds capable of selectively adsorbing a more adsorbable component of a feed gas mixture from the less adsorbable component thereof; (1) feed gas pressurization of each adsorbent bed from an intermediate pressure to the upper, super-atmospheric adsorption pressure; (2) feed gas introduction to the feed end of the bed at said upper adsorption pressure, with adsorption of the more adsorbable component and simultaneous withdrawal of the less adsorbable component from the product end of the bed; (3) countercurrent depressurization to a lower pressure, with release of gas from the feed end of the bed; (4) evacuation to a lower sub-atmospheric, i.e., vacuum, desorption pressure; (5) optional purge, typically by the introduction of a small amount of product gas to the product end of the bed at the lower desorption pressure; and (6) repressurization of the bed to the intermediate pressure level. This VPSA processing sequence can be used in a single bed system or in multi-bed systems containing two or more adsorbent beds. In variations of such processing, a co-current depressurization step or steps can be employed in which gas is released from the product end of the bed, as for pressure equalization to an intermediate pressure with another bed in the system.
The PSA process, including the VPSA process, is a transient process that is influenced by external disturbances and variables. In some cases, once a disturbance is introduced to the system, it does not automatically self-correct itself in response to such changes. Instead, the problem may grow, and self perpetuate until the PSA process can no longer operate at peak capacity or efficiency. Variables that can affect the PSA process include outside ambient temperature, inlet feed conditions, process equipment variability, process valve positioning and response time, and a variety of other factors. In order for the PSA process to run optimally, it must be monitored in order to determine if an outside variable has had an impact on the process. Once this has been determined, steps can be taken to correct and compensate the system in order to force it to run in its optimal condition once again. One variable in a PSA process that has been found to have a great impact on the performance of the system is adsorbent vessel temperature profiles. Typically, in a VPSA process, especially with advanced high capacity adsorbents, the temperature profile in the axial direction follows these trends:
Bottom Adsorbent Vessel Temperature (Inlet Feed Gas End):
30.degree. to 60.degree. F. below the Feed Gas Temperature
Middle Adsorbent Vessel Temperature (at a Point Halfway between the Inlet Feed Gas End and the Product Outlet End of the Vessel):
10.degree. to 30.degree. F. below the Feed Gas Temperature.
Top Adsorbent Vessel Temperature (Product End of the Vessel):
Within .+-.10.degree. F. of the Feed Gas Temperature.
In a PSA process, if the adsorbent vessel temperature profile follows the above trends, then the process is assumed to be running in a stable "tuned" condition. However, a small disturbance in the process can very easily skew the vessel temperature profiles, causing them to be very different from the criteria indicated above. From experience, it can be seen that when the adsorbent vessels have very different temperature profiles from those normally observed in the art, then product recovery will decrease, unit power consumption will increase, and overall plant performance will be lower. This problem becomes even more critical as newer and better performing adsorbent materials are used in PSA, including VPSA, systems.
In order for a VPSA system to perform optimally, it has heretofore been necessary to manually adjust the pressure equalization or repressurization and purge flows for each adsorbent vessel in the system to assure that each adsorbent bed was achieving the production of similar product purities. This has typically been done by connecting an oxygen analyzer to a point downstream of the product withdrawal point to the beds and measuring the breakthrough purities of the product gas. Once the breakthrough purities were balanced, the process was said to be "tuned", and maximum product gas capacity would be produced at the lowest unit power consumption.
In the Abel et al. U.S. Pat. No. 4,995,089, the control of product flow from an adsorption separation system when the downstream customer has a discontinuous use pattern is addressed. A differential pressure controller is used to measure the differential pressure (DP) in a product pipeline. On the basis of the DP value measured in the line, the differential pressure controller sends an appropriate pneumatic signal to a valve in the pipeline in order to control product flow. This automatic control approach is related solely to the control of pipeline product flow to a customer, and is not directed to the actual PSA process operation, or to optimizations that can make the process more efficient.
In another PSA control approach, Schebler et al., U.S. Pat. No. 4,589,436, disclose the use of a small bleed valve in conjunction with an oxygen partial pressure monitor in order to control the partial pressure of oxygen in the product stream. If said partial pressure were to rise above a certain preset limit, the bleed valve could open, thus allowing a small portion of product gas to escape into the atmosphere. This causes the PSA plant to produce more gas, which, in turn, lowers the oxygen purity in the product stream, thus lowering the oxygen partial pressure in this stream. While this patent discusses the control of oxygen partial pressures by increasing product gas flow, it does not relate to the lowering of product flow in an efficient manner, so as to avoid an increase in unit power consumption, and does not relate to PSA vessel temperature, or the use thereof to control product purity from a specific PSA vessel in response to the process disturbances referred to above.
Another automatic control for a PSA system is disclosed in the Gunderson patent, U.S. Pat. No. 4,725,293. In order to control impurity levels in the product stream, the inlet feed flows are changed in response to the purity levels in the product stream. However, the compression machinery desirably used to provide a feed stream to the PSA system are constant displacement machines, and the actual volumetric inlet feed gas, e.g., air, is relatively constant, with cycle times being altered in order to change the total amount of feed gas used in a PSA process. In the practice of the approach recited in the patent, a reduction in the feed gas, with other processing variables kept constant, will result in a corresponding reduction in product flow. In addition, the patent makes no mention of the monitoring of adsorbent bed vessel temperatures in order to control product purity in the course of PSA processing operations.
The use of PSA systems to supply oxygen under variable demand conditions is disclosed in the Grader patent, U.S. Pat. No. 4,643,743. At maximum design capacity of the PSA process, the oxygen product/feed air ratio is a set value. As oxygen demand level from a customer falls from design flow conditions, the oxygen product feed air ratio is increased pursuant to the patented process. The overall product purity level decreases, but the actual oxygen content level in the product stream passing to a wastewater treatment operation is maintained at the desired flow level. Thus, the feed air flow is decreased, or the product flow rate is increased, thereby reducing the overall oxygen purity, but supplying the correct oxygen flow to the customer under reduced demand conditions. In the practice of other PSA applications, it is desired to maintain the oxygen purity at a constant level. The patent provides no teaching with respect to bed temperature monitoring in order to produce constant purity from each adsorbent bed in a PSA processing operation.
The Miller et al. patent, U.S. Pat. No. 4,693,730, discloses a method for controlling the purity of a gas component in a PSA product stream. Co-current depressurization, i.e., pressure equalization, gas is analyzed to determine whether a product purity problem exists. Once this is determined, then action can be taken to restore the purity level of the product stream to its correct level. The patent suggests three approaches to correct a purity problem existing in the process. Thus, the adsorption step time can be adjusted in order to control impurity loading in each adsorbent vessel of a PSA system; the final depressurization step pressure can be adjusted to avoid impurity breakthrough; or the amount of purge gas entering each adsorbent vessel can be adjusted during the purge step. Such actions are taken in response to the monitoring of the pressure equalization gas purity level. The patent does not suggest bed temperature monitoring, nor efficiencies in power consumption in turning down product flow from a PSA system when a customer does not draw maximum design flow rates from the process.
The method of tuning a PSA system by the Miller et al. approach requires sampling of the oxygen approach breakthrough purities of the adsorbent beds in the system. This requires the use of an additional oxygen analyzer and an onsite adjustment of the process controls in order to "tune" the PSA system and balance the product flow and purities between the adsorbent beds. This procedure requires several iterations over a relatively long period of time, typically about 12-24 hours.
There is a need in the art for an improved method of tuning PSA systems, including VPSA systems. While controlling and changing aspects of the product stream in order to optimize product purity in the VPSA system has thus been suggested, the approach of tuning adsorbent vessels, in order to improve process performance, has not been disclosed in the art. The advantage of an approach directed to the tuning of adsorbent vessels would be that such an approach would attempt to compensate for any process inefficiencies before they are able to negatively impact PSA plant performance. In the cases of the prior art approaches, the monitoring of the product stream is to determine whether there is a process problem that needs to be corrected. At this point in time, product flow and/or purity has already been affected, and must be remedied. The solving of potential process problems before they occur is inherently a more advantageous way in which to control the PSA, e.g. VPSA process.
It is an object of the invention to provide a process for tuning PSA, including VPSA, systems for maintaining stable, high performance operation.
It is another object of the invention to provide a VPSA vessel tuning process based on monitoring adsorbent vessel temperature profiles during the course of VPSA operations.
It is a further object of the invention to provide a VPSA tuning process automatically compensating for the adverse effects of processing disturbances and enabling optimum operating conditions to be maintained.
With these and other objects in mind, the invention is hereafter described in detail, the novel features thereof being particularly pointed out in the appended claims.

Tuning of vacuum pressure swing adsorption systems


A communication method in a cordless telephone system having a base unit with which a plurality of portable units can be registered, and a portable unit registrable with a plurality of base units. In the method, if the base unit goes off-hook for requesting a call, a busy signal is sent to all the portable units registered with the base unit. If the call is terminated in the base unit, a call termination signal is sent to all the portable units. Upon reception of the busy signal, a portable unit stores data indicating that the base unit is busy in a selection table of a memory. For initiating a call, the portable unit sends a call request signal to a primary base unit listed in the selection table if the primary base unit is not busy, and otherwise, to another idle base unit. When a call termination signal is received from the busy base unit, the busy state indicating data is deleted in the selection table.

1. Field of the Invention
The present invention relates to a cordless telephone system, and in particular, to a communication method in a cordless telephone system.
2. Description of the Related Art
A cordless telephone system is typically composed of a base unit which is connected to a central office line and a portable unit for communicating with the base unit or with a different wired/cordless telephone while a user roams within a predetermined area. Though one portable unit is generally registered with a base unit, the number of registered portable units per base unit can be increased. That is, in addition to a portable unit provided with the base unit, another portable unit can be purchased and registered with the base unit. In this manner, two or more portable units are registered with a single base unit. Use of a portable unit registered with a base unit allows a user to conveniently communicate without moving to the location of the base unit.
Many homes and offices currently use two or more telephones by connecting the telephones in parallel to a single telephone line or by connecting the phones to different telephone lines. In the first case, the telephones are assigned an identical phone number so that only a single call can be performed by a subscriber at a given time. In the latter case, each telephone line is assigned its own phone number, and each line can support a call.
In using a cordless telephone system in the above cases, one or more portable units are registered with a base unit and a call with a portable unit is performed via the base unit. Therefore, when two or more portable units are registered to a base unit, a first user cannot make a call with a portable unit when the base unit is engaged in a call from a second user with another portable unit. This results in inconvenience to the user who must wait to initiate a call or perform the call on another telephone system.

Expanded communication method in cordless telephone system