A system for characterizing tissue includes a probe that delivers a continuous and periodic mechanical vibration to a tissue of a subject; an ultrasound emitter that emits a sequence of ultrasound shots and an ultrasound receiver that receives corresponding echo signals to track how the tissue is moved by the periodic mechanical vibration delivered to the tissue; and a control module programmed to provide homogeneity information to an operator of the system, the homogeneity information being determined from at least some of the echo signals and being representative of the ability of the tissue to transmit elastic waves and of the homogeneity of the tissue with respect to the propagation of elastic waves.

It is well known that the stiffness of liver tissue correlates with degrees of liver cirrhosis and other diseases, and that the speed at which a shear wave travels through a region of interest in a subject's liver is directly related to the stiffness of the liver. As a matter of fact, in soft tissues, the stiffness (Young's modulus) can be deduced from the tissue density (ρ) and the shear wave speed (Vs) using the formulae E=3ρVs2. The density of soft tissues is close to 1000 kg/m3. E is expressed in kilopascals and Vs in meter per second (m/s).
To characterize liver or other organ stiffness by shear wave speed measurements, a technique called "harmonic elastography" described for example in the document "Probe Oscillation Shear Wave Elastography: Initial In Vivo Results in Liver" by D. C. Mellema et al., published in IEEE Transactions on Medical Imaging, volume 37, issue 5, May 2018, has been developed.
According to this technique, an array transducer for 2-dimensional B-mode ultrasound imaging is placed on contact with a subject's body and vibrated at a low frequency, typically comprised between 30 Hz and 100 Hz. Ultrasound shots are then emitted to track how the tissue of the subject is moved by this low frequency periodic vibration. An instantaneous 2-dimensional map (a kind of 2D snapshot), showing tissue displacement caused by the low frequency periodic vibration at different points distributed over a 2-dimentional section of the tissue of the subject, and at a same instant, is thus determined (see FIG. 9a of the above mentioned document by D. C. Mellema et al.). A filtered 2-dimensional displacement map is then determined by a complex spatial mode filtering (FIG. 9b, or 8b of Mellema et al.). An inversion algorithm then enables one to derive (from the 2-dimensionnal deformation map) a 2-dimensional map representing the value of the shear wave speed at different points distributed over an entire 2-dimentional section of the tissue (FIG. 8c of Mellema et al.). With this technique, values of the shear wave speed are thus derived from spatial information contained in the instantaneous 2-dimensional displacement map.
But implementing such a method requires a quite complex multibeam ultrasound device, suitable for 2-dimensional ultrasound imaging. And the processing of a single instantaneous 2-dimensional deformation map requires a lot of time, typically 3 vibration periods, according to Mellema et al. This long processing time prevents from sampling a whole vibration period all at once, from a temporal point of view (as explained in the capture of FIG. 3 of Mellema et al.). More precisely, in Mellema, a couple of two ultrasound shots is emitted (every 100 ms) and then, two corresponding ultrasound echo signals are acquired and processed to compute the displacements in the medium at the time the couple of ultrasound shots was emitted. This procedure is then repeated 100 ms later, and so on (with a repetition rate of 10 hertz). Due to the long processing time required to compute and analyze each 2-dimensional deformation map, this procedure cannot be repeated with a higher repetition rate. Therefore, with this technique, a whole vibration period cannot be sampled all at once (as it would require a repetition rate higher than the frequency of the mechanical vibration, namely higher than 100 hertz). Thus, this harmonic elastography technique enables 2-dimensional spatial imaging and is focused on spatial properties of the deformation field, but has a poor temporal resolution and is influenced by tissue motion due to respiration or heart beating for example.
Besides, measuring shear wave speed by harmonic elastography is considered as less reliable and less accurate than by transient elastography, harmonic elastography generally providing over-estimated speed values. Indeed, with harmonic elastography, the periodic mechanical vibration delivered to the subject travels in the subject's tissue as an elastic wave mixing shear waves and compression waves (whose propagation speed is much higher than the one of shear waves), these two components being hardly separable due to the repetitive, continuous nature of the vibration. Furthermore, harmonic elastography measurements can also be skewed by elastic wave reflections inside the tissue, which may create stationary waves patterns (again, due to the repetitive, continuous nature of the vibration).
As a result, the time-harmonic elastography technique described above provides valuable spatial information regarding the structure of the part of the subject's body under examination, thanks to its 2-dimensional imaging capabilities. But it generally provides shear wave speed values that are not very accurate. The main reasons for this lack of accuracy are the combination of shear and compression waves, the influence of diffraction effects due to the large size of the vibration source, the influence of motions such as respiratory motion given that the displacements are usually captured during several cycles of vibration and the out of plane motion that are not measured. These problems result in artefacts on the image that must be interpreted with a lot of caution especially when quantitative measurements are to be provided.
Transient elastography techniques thus seem more adequate than time-harmonic elastography techniques to precisely measure shear wave speed in quite large and homogeneous organs like liver or spleen.
Transient elastography is based on a different approach than the harmonic elastography technique presented above. Instead of recording an instantaneous 2-dimentional map of the tissue deformation (and deriving shear wave speed values from the spatial properties of this map), transient elastography is focused on a spatio-temporal tracking of a transient mechanical pulse delivered to the tissue.
A well known transient elastography system is the FIBROSCAN® system (an ultrasound-based elastography apparatus for measuring the stiffness (or elasticity) and ultrasound attenuation of tissues and organs), produced and sold by Echosens SA of Paris, France, which enables an operator to non-invasively measure liver or other organs stiffness to assess the organ's health.
With the FIBROSCAN® system, an operator places the tip of a probe, that has a rather small diameter (typically comprised between 5 and 10 mm), in contact with the subject's body, in front of the expected area of a subject's liver. The operator then presses a button to make the probe's head deliver to the subject a transient, low frequency mechanical pulse (the spectrum of this pulse is centered on a frequency comprised typically between 10 and 500 hertz). This pulse generates an elastic wave that travels in the subject's body. An ultrasound transducer mounted on the probe's head, in contact with the subject's body, then sends out a number of ultrasound shots into the tissue, with a high repetition rate, of 2 kilohertz at least. The echo signals, corresponding to the backscattering of the different ultrasound shots emitted, are acquired by the probe to track slight movements of the tissue caused by the elastic wave passing through. The tracking is performed using correlation techniques applied to successive echo signals. The detected movements enable one to compound an elastic wave propagation image showing the tissue deformation both as a function of depth d, and as a function of time t (instead of compounding an image showing tissue deformation as a function of two different spatial coordinates, but at a given, fixed instant). FIG. 1 shows such an elastic wave propagation image 105, sometimes referred to as an "elastogram".
Contrary to other elastography methods, the FIBROSCAN®'s probe uses a favorable symmetric design. The ultrasound transducer is a single element transducer mounted on the axis of the vibrator. The axis of the ultrasound transducer coincides with the axis of the vibrator, which is why the displacements induced by the vibrations are largely longitudinal and therefore aligned with the ultrasound beam axis. The measurement of the displacement is significantly improved in such conditions since the out-of-axis displacement are much more difficult to measure using ultrasound. Other elastography devices, especially harmonic ones, are more complex. They use multiple element ultrasound transducer (usually liner or convex arrays) as they aim at providing a map of the mechanical properties in 2D or 3D to locate heterogeneities. The symmetry of these systems is much more complex. Displacements induced by the vibrations are not aligned with the ultrasound beam(s) by design. They require more computation time as they process much more data (several ultrasound lines) and use sophisticated inversion algorithm to assess the mechanical properties in 2D or 3D. Furthermore, they are very slow to operate.
The mechanical pulse delivered by the FIBROSCAN® probe's head generates both a shear wave and of a compression wave. In other words, the elastic wave mentioned above combines a shear wave and a compression wave. But these two waves have very different propagation speeds and, thanks to the transient nature of the mechanical excitation, they can be easily separated in time and identified in the elastic wave propagation image. For example, referring to FIG. 1, this figure shows an elastic wave propagation image 105. In FIG. 1, the compression wave is identified by the reference sign 105C, while the much slower shear wave is identified by the reference sign 105S. Also shown in FIG. 1, is the region of interest (ROI) which is bound by two dashed lines at 25 mm and 65 mm, which corresponds to the depth under the patient skin where liver is typically located. This elastic wave propagation image can thus be used to precisely determine the propagation speed of shear waves in the tissue to be characterized, from which the stiffness of this tissue can be derived. These stiffness results 106 are then provided to the operator, as represented in FIG. 1 which shows different graphs 101, 102, 105 and indicators 103, 106, 107 displayed to the operator by means of a display screen of the FIBROSCAN® system.
The FIBROSCAN® system also enables one to measure the attenuation of the ultrasound signals that are used to track the shear wave, which is useful as ultrasound attenuation correlates with the amount of fat content in the liver (see FIG. 1, ultrasound attenuation results 107).
While the FIBROSCAN® technology works well, it is sometimes difficult for an operator to know if he/she has correctly positioned the probe, in front of an area of homogeneous liver tissue, or if he/she is even aiming the probe at the liver at all. Ribs in front of the liver, blood vessels, liquid pockets (ascites) or other artifacts of non-homogeneous tissue such a cysts or tumors in the liver tissue can produce erroneous measurements of both tissue stiffness and ultrasound attenuation. In addition, an operator may believe that he/she is aiming the probe at the liver, when in fact the probe is too close to the lungs or other internal organs. As a result, the system may not be able to obtain accurate measurements.
To help the operator find an adequate probe position, the FIBROSCAN® system is configured to continuously transmit ultrasound shots and to acquire corresponding echo signals while the operator is searching for an adequate probe position. A-mode and TM-mode graphs are displayed and refreshed in real time to help the operator find the adequate probe position. FIG. 1 shows an example of such an A-mode graph 101 and TM-mode graph 102. A TM-mode graph represents the ultrasound echo signals successively acquired after the ultrasound echo signals have been processed. Processing of the ultrasound echo signals includes, e.g., envelope computation and decimation. The TM-mode graph shown in FIG. 1 is a 2-dimensional image in which each column represents one of the processed ultrasound echo signals acquired. Each column is representative of an instantaneous 1-dimensional image showing, as a function of depth d, how the part of subject's body located that is in alignment with the probe backscatters ultrasound waves. The successive ultrasound echo signals acquired are displayed side-by-side to show the evolution over time t of this 1-dimensional image (this evolution being caused by slight probe movements or by organ movements caused by respiratory motion).
As shown in FIGS. 1 and 2, the TM-graphs may provide useful information regarding the probe 3 positioning. Indeed, when the probe axis x is aligned with a thick, homogeneous part of the liver 4, the TM-graph 402 usually looks like a stack of thin horizontal sheets and has a homogeneous aspect, both horizontally and vertically, as shown in FIG. 4. By contrast, when the probe axis x is close to an edge of the liver 4, the TM-mode graph 202, 302 often has a discontinuous aspect, either horizontally (FIG. 2) or vertically (FIG. 3).
Still, positioning the probe adequately on the basis of the TM-graphs remains quite difficult and requires a proper training of the operator. Furthermore, as will be appreciated by the skilled artisan, an inadequate probe positioning may lead to an inadequate measurement and an inaccurate diagnostic of the patient's condition.
Ultrasound signals displayed in TM-mode or A-mode graphs, though providing some information regarding the position of the probe, are not predictive of the shear wave propagation. In some situations, these graphs may appear adequate, as if the conditions were suitable for transient elastography measurements, whereas no shear wave can actually propagate. This can happen in the presence of liquid interposition (see the TM-mode graph 602 of FIG. 6), air interposition (see the TM-mode graph 602′ of FIG. 6), narrow intercostals space, etc. . . . . Furthermore, though a vessel may not be observed on the ultrasound signals because it is isoechoic, it may disturb the shear wave propagation. FIG. 6 shows a TM-mode graph 602′″ acquired in the presence of an isoechoic vessel, in which the vessel remains invisible (the position of this vessel is identified by an arrow).
The guidance using ultrasound data is not good enough because it cannot predict the propagation of the shear wave as ultrasound and elastic are not sensitive to the same conditions. A good ultrasound signal does not always result in a good shear wave propagation. Some elements that influence the shear wave propagation do not affect ultrasound propagation. This is the case of isoechoic parts that can be a vessel, a cyst, a liquid with particles, a stiff or soft tumor, etc.
Due to the limitations of the conventional TM-graph guiding, the operator generally does not find an adequate probe location at the first try he/she attempts to position the probe. In practice, it turns out that the operator often has to trigger the transient elastography measurement several times, testing different positions by trial and error, before finding an adequate position and recording an elastic wave propagation image appropriate to characterize liver stiffness. This is time consuming, all the more that the operator has to hold the probe still and firmly before triggering a transient elastography measurement. As will be appreciated by the skilled artisan, such attempts can be unpleasant for the patient under examination as the patient receives a small mechanical punch each time the operator conducts a measurement. Moreover, such attempts can discourage the operator to find an adequate position and thus increase the failure rate.
It is thus desirable to develop a system for characterizing tissue, suitable for a precise characterization of the viscoelastic properties of this tissue and having improved guiding capabilities compared to the FIBROSCAN® system described above.

System for characterizing tissue and associated method


A battery power supply system (1) for suppressing the overall temperature variation of a plurality of battery module groups (61 to 65) includes a box (2) having a cooling air inlet (3) on one end face and a suction fan (4) within a section at the other end, and a battery assembly (5) installed in an intermediate section within the box (2). The battery assembly (5) includes a plurality of battery module groups (61 to 65). Each of the battery module groups (61 to 65) includes a plurality of rod-shaped battery modules (7). When a gap between outer peripheral faces of two adjacent rod-shaped battery modules (7) of the first battery module group (61), which is closest to the cooling air inlet (3), is a, and a gap between the outer peripheral face of the rod-shaped battery modules (7) of the first battery module group (61) and the outer peripheral face of the adjacent rod-shaped battery modules (7) of the second battery module group (62) is b, the ratio a/b of the gaps a and b is set so that 1.0<a/b≦2.0.

As this type of battery power supply system there is a conventionally known arrangement that includes a box having a cooling air inlet on one end face and a suction fan within a section at the other end, and a battery assembly housed within the box. The battery assembly is formed from a plurality of battery module groups that are arranged at intervals in parallel to each other along a cooling air flow direction; each battery module group is formed from a plurality of rod-shaped battery modules that are arranged, within an imaginary plane intersecting the cooling air flow direction, at equal intervals with their axes intersecting the cooling air flow direction, and the axes of one rod-shaped battery module and another rod-shaped battery module that is adjacent thereto in the cooling air flow direction are positioned within an imaginary plane that is parallel to the cooling air flow direction.
In this case, with regard to each battery module group, the module group that is closest to the cooling air inlet is cooled best, but the extent of cooling of the battery module groups decreases the further away they are from the cooling air inlet, while also depending on the positional arrangement, and the overall temperature variation across the battery module groups is large.
In order to improve the durability of the battery module groups by cooling them uniformly, certain cooling measures have been taken. For example, one measure that has been taken is to place synthetic resin rectifying plates in spaces surrounded by four battery module groups, thus appropriately controlling the flow rate of the cooling air in the vicinity of the battery modules and thereby suppressing the temperature variation (e.g., Japanese Patent Application Laid-open No. 10-255859).
However, this conventional arrangement has the problems that, since a rectifying plate manufactured with high dimensional precision is required, the cost of a mold therefore is high, and in the initial stages of cooling the rectifying plate must be cooled at the same time, which is wasteful; furthermore, since the cooling air passage is narrowed by the rectifying plate, dirt and dust easily collect in the passage and there is also a possibility that a short circuit might be caused when condensation, etc. occurs and, moreover, since the cooling air passage is a long, narrow passage, the overall pressure loss across the box is high, and a high output suction fan is required.


An underground mine tire 20 having a nominal bead diameter of 20.0 inches or less has a carcass, a tread 25 and a pair of rubber sidewalls 23, each extending along the outer periphery of the carcass 21 below the tread 25. The tire 20 has a nominal bead width D greater than 8.50 inches and an overall diameter of less than 55 inches. The carcass 21 has at least one radial steel cord reinforced ply 24.

Underground mining for ore or coal is a highly mechanized industry involving specialized equipment to cut through rock and coal deposits to yield a harvest of ore or coal. This use of vehicles to haul the mined material has evolved to where large heavy loads of material are moved on vehicles that must travel within the cut seams hauling material out. Many of these seams are limited in height to less than 2 meters (6 feet), typically 5 feet (60 inches) or less and can run several miles in length. Mining operations make money by quickly moving tonnage of material. The more material that can be moved the more profitable the operation can be.
To haul material from a mine, vehicles as described in U.S. Pat. No. 4,890,684 are used. These vehicles are wide and low permitting them to travel within the seams. FIGS. 4A and 4B show a representative view of an exemplary articulated vehicle. As can be readily seen the tires have a diameter almost equal to the vehicle height. The carrying load capacity combined with the size of the tires dictates the amount of ore that can be carried in the bucket or trailer. The ore is typically filled to a point just clearing the ceiling of the cut seam. To carry more ore one can add more axles and add tires as is commonly seen in large commercial dump trucks.
Historically in above ground vehicles like commercial trucks, dual wheeled axles were used to increase loads. In off-road mining the tires increased in overall diameter. For the very large carrying capacity these tires are in excess of 120 inches (10 feet) in diameter. The use of dual or multiple tires on the axles of underground vehicles has not been an accepted practice for a variety of reasons. Similarly the use of large diameter tires has not been accepted because as the tire's sidewalls are increased, the entire vehicle is elevated due to the taller, larger outside diameters, these larger OD tires when used in the seam reduce the amount of ore that can be piled on the vehicle.
Ideally very small wheels would be used to haul ore. In early mining steel rails would be laid on the mine floor to enable buckets to be moved on small steel wheels. While this yielded big carrying capacity it increased cost and labor. In today's modern mines the equipment can cut seams so fast that the use of such rails is cost prohibitive. Accordingly, underground mining relies heavily on the tire preferably foam filled or solid filled or pneumatic as the most efficient structure to carry the heavy loads.
In order to increase the durability of such tires a massively thick tread and sidewall is employed. These tires operate at relatively low speeds and thus thick rugged cut resistant tires are permissible without a major concern over heat build up caused by hystoresis.
The overall load carrying capacity is limited by the overall strength of the carcass. In a radial ply tire the carcass has generally one or more radial steel cord reinforced rubber coated plies anchored or wrapped around a pair of bead structures and has a belt structure including typically at least 2 preferably more steel cord reinforced belt layers. Bias tires have many carcass plies/layers oriented at opposing angles of 35° to 65° relative to the equatorial center plane of the tire generally and a breaker structure of several layers of inclined cord reinforced layers.
The present invention provides a solution to the problem of increasing the overall load carrying capacity of underground mine tires without requiring an increase in the outer diameter size of the tire.
The present invention is adapted to be used with currently available mining equipment without requiring any modifications to the vehicle.
The present invention permits a more efficient use of the tire and improves the overall durability and serviceability of the tire.


An antimicrobial cleaning composition having a pH of from about 9 to about 14 wherein the composition comprises a bispyridinium alkane antimicrobial active and the composition is substantially free of a quaternary ammonium antimicrobial active.

Antibacterial household cleaners often comprise antibacterial actives such as quaternary ammonium compounds to provide surface sanitization or disinfection, these compounds tend to be deposited on the surface as a visible residue, which leaves the user with an impression that the treated surface has not been cleaned well. This is because the surface appears streaky and has poor shine. Moreover, the treated surface can feel slightly sticky, which further leaves an impression with the user of poor cleaning. In addition, quaternary ammonium compounds typically interact with the cleaning surfactants present in the composition. The result is that the antimicrobial efficacy of the composition is reduced, or else, higher levels of the antimicrobial active must be present. The use of high levels of quaternary ammonium antibacterial actives in cleaning products might not be desirable for environmental reasons. Another drawback is that their level is restricted in products to be used on food contact surfaces.
More environmentally friendly antibacterial products can be made using natural acids such as lactic acid or citric acid, and/or botanical extracts, but the products based on botanical extracts do not have a robust, fast acting antibacterial efficacy, and the acidic products do not provide good removal of greasy soils. There is therefore the need for an antibacterial cleaner that has a good environmental and human safety profile, that shows strong antibacterial efficacy, that can be used on food contact surfaces and that shows good cleaning, even on tough greasy soils, and leaves the surfaces shiny and without streaks.

This patent is subject to a terminal disclaimer.


A method of providing error information to an outside of a hard disk drive, the hard disk drive, and a data processing apparatus therefor. The hard disk drive includes a first interface unit transmitting data reproduced from a medium to the outside and receiving data to be recorded on the medium from the outside, a hard disk controller controlling data to be recorded on the medium or reproduced from the medium and providing the error information including a type of an error occurring in the hard disk drive, a state information manager managing the error information provided by the hard disk controller and state information indicating operation conditions of the hard disk drive, and a second interface unit outputting the error information and the state information provided by the state information manager to the outside when the error occurs.

1. Field of the Invention
The present invention relates to a hard disk drive (HDD), and more particularly, to a method of providing information on errors occurring in an HDD, an apparatus to process the error information, and an HDD using the same.
2. Description of the Related Art
Recently, as more advances are being made in the digital era, there has been increasing attention paid to personal video recorders (PVRs) capable of recording broadcast programs for more than 24 hours without a need of an additional tape.
A PVR, also called a digital video record (DVR), is an apparatus to store a digital video stream in real time and to reproduce the stored digital video stream, and includes a hard disk drive (HDD).
During recording data on and reproducing data from a HDD, errors may occur due to an operation temperature of the HDD, defective elements, or a periodic or non-periodic phenomenon of the HDD. When the HDD fails to record data on or reproduce data from a desired sector thereof, the HDD tries to record data on or reproduce data from the desired sector again when the desired sector comes into a predetermined position again while a disk is rotated in the HDD. At this time, the HDD performs various error retrieval operations, such as an off-track reading, an increase or a decrease of a cut-off frequency, an increase or a decrease of a bandwidth, or a variation of a gain value of a finite inverse response (FIR) filter. Such a process is called a retry. If the data corresponding to the errors are not retrieved through the retry process, the HDD notifies a host that unrecoverable errors have occurred and thus to record data on or reproduce data from the desire sector of the disk is not possible.
A conventional system communicates with the HDD installed therein by using ATAPI commands. Among the ATAPI commands, there is a command to notify a host of state of the HDD.
FIG. 1 is a flowchart of the operation of a conventional hard disk drive. Referring to FIG. 1, a command is applied to the HDD from a host in operation S102. The HDD executes the command issued from the host in operation S104. If no error occurs while executing the command, the command is completed in operation S110. If a predetermined error occurs while executing the command in operation S106, the execution of the command is stopped in operation S108. The host is notified of whether or not the performance of the command is stopped or is completed in operation S112.
Further, a content, which the host is notified of by the HDD and a type of the content are defined by an ATAPI command reference.
FIG. 2 is a block diagram of a conventional HDD performing the operation shown in FIG. 1. In FIG. 2, reference numerals 202 and 204 represent an integrated drive electronics (IDE) controller and an HDD, respectively. The IDE controller 202 and the HDD 204 are interfaced via an IDE interface and receive information from or transmit information to each other by using the ATAPI commands.
IDE takes part in transmitting information between a main board and a data storage. AT attachment (ATA) represents terms established by American National Standards Institute (ANSI) adopting the IDE as a standard. Among IDE ports, there are a primary port and a secondary port. The primary and secondary ports each include a master channel and a slave channel. In most cases, the HDD is connected to the primary port, and a CD-ROM is connected to the secondary port.
ATAPI is protocol developed so that a data storage, for example, a CD-ROM, a DVD, or a tape, other than an HDD may share an ATA interface with an HDD. ATAPI is the third ATA standard established by ANSI, after ATA and ATA-2. The reason an IDE interface of the ATAPI is called a packet interface is that a protocol thereof transmits a group of commands, i.e., a packet.
However, to notify a host of whether or not an error has occurred in the HDD in real time, figure out what caused the error, and appropriately respond to the error by using an IDE interface is not possible.
There have been various techniques to diagnose an error having occurred in an HDD, including Japanese Patent No. 1999-184726, Korean Patent Nos. 1998-011130 and 2002-5929, Japanese Patent No. 1997-101905, and Korean Patent Nos. 1998-14546, 2001-58759, and 1995-2353. These techniques provide a method of diagnosing an operation state of an HDD from a host or outside the HDD.
However, such conventional error diagnosing techniques merely check the operation state of an HDD by using a specific program, i.e., a diagnosis program, rather than notifying a host in real time of an error which has occurred during an operation of a disk so as to let the host appropriately respond to the error.
In addition, the conventional error diagnosing techniques use an ATAPI command system, as shown in FIG. 1, and thus they fail to transmit information, which cannot be accepted in the ATAPI command system, to the host.
The conventional error diagnosing techniques can retrieve errors in an HDD by adjusting parameters of the HDD. However, the conventional error diagnosing techniques cannot take any appropriate measure to eliminate an external cause of the error.
For example, a data recording failure may be caused by defects in the HDD or a data transmission system. However, the conventional error diagnosing techniques only eliminate internal causes of the error which has occurred in the HDD, which means the conventional error diagnosing techniques are unable to solve such a recording failure error caused by defects in the data transmission system.
In particular unlike in a PC, to freely separate an HDD from a PVR is difficult, and the PVR does not store a diagnosis program. Accordingly, in a case where an error occurs in the HDD due to such an inconvenient structure of the PVR, for a user to appropriately control an operation of the PVR is not possible.
In the related art, to let an HDD notify a host of information on an error having occurred in the HDD by redefining ATAPI commands is possible. However, the redefinition of the ATAPI commands brings about standards-related problems which cannot be solved using a current level of technology.

Method of providing information on errors of hard disk drive, hard disk drive therefor and information processing apparatus therefor


A memory device is described which includes latching wordline driver circuits. The wordline driver circuits include a latch responsive to phase lines of an address tree decode configuration. The latch has been described as a single latching transistor which allows transitions in shared row address lines while maintaining an active wordline signal. The latching wordline driver is particularly useful in multi-bank memory devices where row address lines are shared between the memory banks.

Integrated circuit memory devices typically include address inputs for receiving address signals to identify a memory location which is to be accessed for storing or retrieving data. The received address signals are decoded and used to access memory cell locations. In conventional memory devices, memory cells are accessed through access, or isolation Transistors. These Transistors are activated by a signal provided on a "wordline" coupled to a gate of the Transistor. As such, the signal on the wordline must remain valid while the memory cell is accessed. Because the wordline signal is typically generated using the address signals, if the address signals are changed during an access operation, memory data read or write operations may be prematurely interrupted resulting in a memory operation error.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a memory device which latches a wordline signal to maintain access to memory locations while allowing externally provided address signals to change. In particular, memory devices which contain multiple banks of memory cells and share common address inputs will experience faster data access by allowing address signal changes to occur for a first memory bank while simultaneously maintaining access to a second memory bank.

Latching wordline driver for multi-bank memory


A power integrated circuit including a substrate of semiconductor material having a first conductivity type on which is formed a first epitaxial layer of the same conductivity type. In a first portion of the first epitaxial layer are formed first and second diffused regions having respectively first and second conductivity type. The first and the second diffused regions are isolated from a power stage included partially in a second portion of the first epitaxial layer by an annular region having the second conductivity type. Over the first epitaxial layer is formed a second epitaxial layer having the first conductivity type in which are extended the first and the second diffused regions to permit forming a control circuitry for the power stage.

1. Field of the Invention
The present invention relates to a power integrated circuit and to a related manufacturing process.
2. Description of the Related Art
In conventional power integrated circuit technologies, in which the power stage is preferably of the vertical DMOS type of structure, some limitations are present when these technologies are used in high-frequency applications or when the substrate includes high-voltage (e.g. >300V/.mu.sec) transients. These limitations are due to the presence of high junction capacitances between the substrate and diffused and isolated regions having respectively an N-type and a P-type conductivity and including the control circuitry of the power stage. The dimensions of these junction capacitances are proportional to the dimensions of the diffused and isolated regions. When there are abrupt changes in the voltage present on the substrate these junction capacitances transmit disturbances to the control circuitry of the power stage and compromise its operation. It would therefore be necessary either to reduce drastically the dimensions of the control circuitry or provide in the substrate a low resistance through which conveying to a ground terminal a large part of the current injected capacitively from the substrate to the control circuitry.
A known technical solution for solving these problems is described in European Patent Applications 95830060.0 and 94830229.4, both of the same applicant.
The first patent application describes a process for providing a power integrated circuit including a semiconductor substrate in which is diffused a region having an N-type conductivity. The diffused region is isolated from the substrate by an implanted buried region having a P-type conductivity. Specifically, the buried region is formed implanting high-energy boron. Normally the buried region has a thickness of approximately 1 .mu.m and a distance from the integrated circuit surface dependent upon the implantation energy. For example, if the implantation energy used is around 900 kev the buried region will be at a depth of approximately 1.5 .mu.m. To connect the buried region with the integrated circuit surface there is formed through an implantation and a successive diffusion a deep region having a P-type conductivity. The deep region includes two structurally independent regions which contact laterally the buried region. The buried region and the deep region form an annular region including the diffused region. The annular region isolates the diffused region from the rest of the integrated circuit. In this solution the thickness of the diffused region is on the order of 1 .mu.m depending also on the doping of the region. But this thickness is insufficient if the diffused region must also include the control circuitry of the power stage.
The second patent application describes a process for providing a power integrated circuit including a control circuitry incorporated in first and second diffused regions having respectively an N-type conductivity and a P-type conductivity. Again in this case the first and second diffused regions are isolated from the rest of the integrated circuit through an annular region including a buried region, implanted with high energy, and a deep region. When the implantation of the buried region is performed at 900 kev the depth at which the buried region is located does not exceed 2 .mu.m. Considering that the thickness of the buried region is approximately 1 .mu.m the residual thickness towards the surface of the integrated circuit is approximately 1 .mu.m. This thickness is insufficient for providing the control circuitry of the power stage. Indeed, the thermal cycles necessary for forming the power stage cause rising of the buried region to the surface. This shortcoming could be avoided implanting the buried region at much higher energy but the entire process would be much costlier.


Systems, apparatuses, and methods for removal of orbital debris are provided. In one embodiment, an apparatus includes a spacecraft control unit configured to guide and navigate the apparatus to a target. The apparatus also includes a dynamic object characterization unit configured to characterize movement, and a capture feature, of the target. The apparatus further includes a capture and release unit configured to capture a target and deorbit or release the target. The collection of these apparatuses is then employed as multiple, independent and individually operated vehicles launched from a single launch vehicle for the purpose of disposing of multiple debris objects.

Orbital debris in low earth orbit (LEO) is an international problem that threatens the success of scheduled missions and future space ventures. For example, damage from man-made orbital debris is one of the top risks to LEO spaceflight missions. This risk will continue to increase as access to space increases, making orbital debris a global problem that is in need of remediation. Studies have shown that large debris objects are the creation engine for great amounts of smaller, hazardous debris. Thus, an apparatus and method for removal of large, medium, and/or small debris objects may be beneficial to reduce the threat at its source.

System, apparatus, and method for active debris removal

The United States of America as represented by the Administrator of the National Aeronautics and Space Administration


The invention relates to a brake disk for a disk brake, in particular for utility vehicles. Said brake disk comprises two spaced friction rings, which are linked to each other forming an air space and is linked to a wheel hub and/or axle in a rotationally fixed manner. Said brake disk is designed, such that it is fixed to the hub, by means of a separate link piece radially extending, in a manner that said disk can be elastically displaced in the hub axial direction.

The present invention relates to a brake disk for a disk brake and, in particular, for a disk brake for utility vehicles.
Disk brakes for vehicles are known, for example, as sliding-caliper disk brakes, swivelling-caliper disk brakes or fixed-caliper disk brakes. In the utility vehicle field, particularly the sliding-caliper brake has become a successful standard design, in which case the sliding caliper is displaceably disposed on a brake anchor plate rigidly fastened to the wheel axle. Sliding-caliper or swivelling-caliper disk brakes require a component—the brake anchor plate—which is fixed to the axle and which, when the brake is operated, absorbs the circumferential forces of the brake linings with the brake pads. Also, the brake anchor plate holds the caliper, which is slidably or swivellably disposed with respect to the vehicle axle.
If a fixed caliper is used instead of a sliding caliper, the brake disk may be designed as a sliding disk, which is axially displaceably disposed on the wheel axle. During brakings, it is first contacted by a brake pad and then pushed against the brake pad arranged on the opposite side of the brake disk. In this case, generally, the generating of force—that is, the brake application device—and a wear adjusting device are arranged on one side of the brake disk. As the wear increases, the brake disk is also slowly axially slid on the wheel axle in order to compensate the wear of the brake pad.
The relative movement, which the sliding disk therefore has to bridge, can be divided into a working stroke and a wear stroke.
The working stroke is carried out during each brake operation in order to overcome the release play of the brake and compensate for the elasticities of the brake pads and of the caliper during the application of force.
In contrast, the wear stroke is the wear adjusting path, which the caliper carries out over a large number of brake operations, in order to compensate for the wear on the reaction side of the brake. The wear stroke is composed of the wear of the externally situated brake pad and of the externally situated brake disk friction surface and normally amounts to 20-25 millimeters, while the above-mentioned working stroke, and thus the sliding path for overcoming the release play, amounts to only a few millimeters.
If at least one adjusting device is arranged on each side of the brake disk, for example, in each case at least one or more electric-motor-driven adjusting rotating device(s) which move(s) pressure pieces in the direction of the brake pads, the distance between the brake pad and the brake disk can be adjusted on each side of the brake disk.
In such a case, it is necessary to still implement a displaceability of the brake disk for overcoming the release play and for compensating the elastic deformation of the brake pads and of the caliper, in accordance with the above-mentioned working stroke. Correspondingly, the slide bearing needs to have a displacement path however, a correspondingly clearly shorter one.
Although the use of such an adjusting system with at least one or more adjusting devices on each axial side of the brake disk already represents a considerable improvement, as a result of the still axial displaceability of the brake disk, a sliding guide can be implemented, although to a lesser extent. Thus, the frequent operation, typical of the use of a disk brake in a utility vehicle, because of the influencing forces, permanently leads to a wear of the sliding guide by which the brake disk is guided on the hub, resulting in sluggishness which requires corresponding maintenance work.
This is naturally has its costs, which are the result of the maintenance work as well as of the necessary interruptions in the operation of the vehicle.
It is therefore an object of the present invention to further develop the brake disk of the above-mentioned type such that a longer service life can be achieved by the use of constructively simple devices.
This object is achieved by providing a brake disk for a disk brake, particularly for a disk brake of a utility vehicle, having: a) two mutually connected friction rings, between which a ventilating gap is formed; b) a device for implementing an axial mobility of the friction rings relative to the wheel hub and/or wheel axle; and c) wherein the device for implementing the axial mobility of the friction rings is designed as a linking piece arranged on the friction rings and/or connected therewith, for the fastening of the brake disk to the wheel hub and/or wheel axle, which linking piece is constructed separately from the friction rings and can be elastically deformed relative to the friction rings.
Accordingly, the device for implementing the axial mobility of the friction rings is designed as a linking piece, which is arranged at the friction rings and/or is connected with them, for fastening the brake disk at the wheel hub and/or the wheel axle. The linking piece is constructed separately from the friction rings and can be elastically deformed relative to the friction rings.
As a result of this simple construction, an elastic linkage of the brake disk to the wheel hub and/or wheel axle is created, which advantageously does not require an axial displaceability or a bearing between the brake disk and the wheel hub and/or the wheel axle.
Since, to this extent, the brake disk is firmly but not rigidly linked with the hub, the wear parts required for an axial displacement are also eliminated. This results in a considerably lower susceptibility to disturbances so that maintenance and operating costs are correspondingly lowered with respect to the state of the art.
Preferably, the one-part or multi-part linking piece has a radial dimension relative to the wheel axle and is axially elastically deformable relative to the friction rings. Particularly preferably, the linking piece can be axially elastically deformed relative to the friction rings and the wheel axle in such a manner that, as a result of the elastic deformability, an axial mobility of the friction rings relative to the wheel axle is implemented, which axial mobility corresponds to the amount of the working stroke of a disk brake.
The brake disk is, therefore, suitable for, among others, fixed-caliper brakes which have adjusting devices on each side of the brake disk because, in the case of these types of brakes, only an axial deflectability of the brake disk must be ensured that is sufficient such that the working stroke is compensated. Optionally, in a supplementary manner, a low elastic deflectability of the caliper can be combined with the elastic deflectability of the brake disk according to the invention.
According to an advantageous further development of the invention, it is provided that the linking piece is arranged between the two friction rings and is fixedly connected with these, preferably in the outer circumferential area.
In order to obtain a sufficient elasticity, the linking piece, which consists of a springy material, preferably of a spring steel, is provided with recesses by which, depending on their shape and number, a defined restoring force can be reached or adjusted.
The linking piece is connected with the friction rings only in areas, or partially, and can otherwise be moved, that is, deflected with respect to these.
Otherwise, in the case of installation conditions of the brake disk having only a small distance between the inside diameter of the brake disk and the outside diameter of the hub, the invention is suitable for achieving a sufficiently large deflecting movement of the brake disk while the restoring forces are low. On the other hand, the elastic linkage permits the transmission of high braking torques of the brake disk to the hub.
By means of the arrangement of the linking piece in the ventilating duct formed between the two friction rings, a relatively large bending length of the linking piece can be achieved, whereby the linking piece can be sufficiently dimensioned for the transmission of the braking torque and the elastic linking piece does not impair the deflection of the brake disk and thus the function of the brake. Thus, an excessive deflecting resistance could result in an unequal stressing of the two brake disk sides, and thus cause an unequal wearing of the brake.
The linking piece may have many different constructions. One possibility consists of embedding, in the case of a composition casting method for producing the brake disk, the ring-shaped linking piece in a casting core, which is used for generating the ventilating duct of the brake disk. The casting core is constructed such that the casting material penetrates through exterior openings of the linking piece, so that, here, the linking piece is fastened to the two cast and mutually connected friction rings.
Furthermore, the linking piece consisting of a spring plate may be placed between the two friction rings, specifically such that, viewed in the cross-sectional direction, it is arranged approximately in the center of the ventilating duct, thus at the same distance from the respectively adjacent friction rings.
In this case, the linking piece is held in a radially secured manner in the linking areas in the exterior circumferential area between the two friction rings, these being mutually connected by riveting, screwing, welding or another connecting method.
For increasing the elasticity in the pressure direction of the brake disk, the linking piece may also be constructed as a lamellar body and consist of several thin, mutually stacked, individual metal sheets.
It is also contemplated for the linking piece to be produced of a plurality of individual ring segments which, in their respective common abutting areas, are provided with mutually corresponding profiles, whereby a simplification of the mounting and an optimized circumferential force transmission becomes possible.
Instead of many ring segments, which together result in a closed ring, the linking piece may also consist of a plurality of individual elements which each, on one side, are fastened in the circumferential area on the brake disk in the ventilating gap and, on the other side, are connected with the hub. In this case, the individual elements may be constructed and arranged in the manner of spokes and each consist of a spring steel which has a flat or round cross-section.
A brake disk for a disk brake, particularly for utility vehicles, is created which consists of two mutually spaced friction rings which thereby form a ventilating gap and are connected with one another, and which is non-rotatably connected to a wheel hub and/or wheel axle such that it is fastened by the use of a separate, radially extending linking piece to the hub so that it can be elastically deflected in the axial direction of the hub.
Additional advantageous further developments of the invention are described and claimed herein.

Knorr-Bremse Systeme fuer Nutzfahrzeuge GmbH


A data cache for an iSCSI network caches block-level data from WAN servers for use by clients (e.g., LANs). The cache authenticates itself to the WAN servers, and authenticates clients requesting cache access. Mechanisms are provided to prevent clients from accessing cached data intended for other clients.

1. Field of the Invention
The present invention relates to block level cache access in network environments.
2. Description of the Related Art
One development arising from the emergence of networked computing such as the Internet is that an entity's data storage requirements can be met by data storage facilities that are remote from the entity's computers but that are accessible over the network. To provide for fast data transfer through the network, data transfer standards such as the so-called iSCSI (Internet Small Computer Systems Interface) standard have been proposed.
The iSCSI protocol is a block level protocol that is very fast and that is optimized for small, simple commands for facilitating data transfers. It is an implementation of the SCSI protocol that was originally developed to support data transfer between a processor and a local data storage, in particular a local hard disk drive. The iSCSI protocol, on the other hand, is designed to work over TCP/IP (Internet Protocol), which is a general purpose, Internet-related protocol for transferring data through a local area network (LAN) or wide area network (WAN) such as the Internet or local area network. iSCSI thus combines the advantages of peripheral communication ability of SCSI with the data transports developed for IP.
Using what was originally a local hard drive transfer protocol (SCSI) in a WAN environment, such as the Internet, poses challenges. Such protocols emphasize speed but not security, since they were developed for non-networked environments. For example, a local client computer or network (e.g., a LAN) might support a high data transfer rate and low latency, whereas a WAN holding a data repository sought to be accessed by the LAN might not support as high a rate and/or have greater latency.
As recognized herein, a cache can be used to address the above-noted problem, since a cache is a device that temporarily holds data in a fast store and thus can be used as a buffer between a fast network and a slow one. A common function of caches is speculatively pre-fetching read data in anticipation of client requests. As also recognized herein, however, current block-level cache devices do not account for data security. Instead, in block level caches a closed, secure network is assumed, or it is assumed that in an open network data security is simply not a concern. The present invention, however, understands that in the type of network-based data storage applications made possible by modern WAN protocols and in particular made possible by iSCSI, data security at a block level cache is indeed a concern, particularly since several clients might use the same cache as a buffer between their faster, local networks and a slower network such as the Internet.
The present invention has recognized the above-noted problems and provides solutions to one or more of them as disclosed below.

System and method for authenticating block level cache access on network

International Business Machines Corporation


A social networking system generates a friendship page that displays social graph data common to two or more social networking system users. A user requests the page by identifying two or more social networking system. The social networking system obtains social graph data common to the identified social networking system users and generates a friendship page containing that social graph data. The obtained social graph data may include interactions between each of the identified user and/or social networking system objects with which each of the identified users has interacted. Examples of the types of social graph data may include photos, videos, communications, content items, events, locations, friends, family members, biographical data, and location data. The friendship page may be displayed to the requesting user in a web browser or in a native application.

This invention relates generally to social networking, and in particular to providing a social networking system page or other display comprising social networking system information common to multiple users.
Social networking systems commonly provide mechanisms allowing users to interact within their social networks. A social networking system user may be an individual or any other entity, such as a business or other non-person entity. Social networking system information that is tracked and maintained by a social networking system may be stored as a social graph, which includes a plurality of nodes that are interconnected by a plurality of edges. A social graph node may represent a social networking system object that can act on and/or be acted upon by another node. A social networking system object may be, for example, a social networking system user, non-person entities, content items, groups, social networking system pages, events, messages, concepts or other social networking system objects, such as movies, bands, or books.
An edge between nodes in a social graph represents a particular kind of connection between the nodes, which may result from an action that was performed by one of the nodes on the other node. Examples of such actions by a social networking system user include listing social networking system objects in a user profile, subscribing to or joining a social networking system group or fan page, sending a message to another social networking system user, making a purchase associated with a social networking system node, commenting on a content item, or RSVP'ing to an event. Thus, if a first user establishes a connection with a second user in the social networking system, the users may be represented by nodes, and the connection may be represented by an edge connecting the nodes. Further, if the first user sends a message to the second user, or tags the second user in a picture stored by the social networking system, the message and tagging may be represented by additional edges between the nodes. Alternatively, the message and picture may be represented by nodes, which are connected by edges to the nodes representing the first and second user. A social graph, therefore, may be used to track the interactions between social networking system objects.
A first social networking system user may want to view some or all of the social graph data, such as social networking system objects and interactions, between or common to a second social networking system user (referred to herein as "relationship data"). Current social networking systems contain interfaces for viewing certain selected communications between two social networking system users, but only in specialized circumstances and only of one particular type of communications. Further, social networking systems contain pages that display limited types of social networking system information in small quantities generally related to one or more social networking system users, but do not contain pages which comprehensively list social graph data common to multiple social networking system users. Social graph data common to multiple social networking system users is decentralized and spread across multiple social networking system pages, which may require navigation that is prohibitively time-consumptive. Thus, there is a need for a solution that aggregates social graph data common to multiple social networking system users and that presents this aggregated data in a single interface to provide an enjoyable, useful, and efficient experience for social networking system users.

Display showing intersection between users of a social networking system


A parking violation recording system capable of recording violations based on the location of a violating vehicle, is provided. The system includes at least one camera located on a mass transit vehicle, oriented so that it is capable of viewing a violating vehicle and recording an image containing violating vehicle information of the violating vehicle; at least one locator provided on said mass transit vehicle and capable of providing data for determining the geographic position of the mass transit vehicle; and a data processing sub-system, coupled to the at least on camera and the at least one locator for recording both the violating vehicle information and the geographic data in a violation data record. In another aspect, the invention is directed to a method of enforcing bus zone regulations. The method includes recording an image containing violating vehicle information of a violating vehicle illegally parked in a bus zone with at least one camera located on a mass transit bus, and storing the violating vehicle information in a data record associated with a data processing system located on the bus.

The invention relates to enforcement of parking regulations and more particularly to a system and method for recording parking violations for vehicles illegally parked in restricted parking areas, in order to generate parking violation citations. In a specific embodiment, the system and method is directed to recording parking violations for vehicles parked in the no parking zone of a bus stop.
Municipal governments enact regulations to govern the parking of cars and other vehicles along city streets. These regulations include no parking, no stopping and no standing zones to ensure access to certain areas along the side of the road for a variety of reasons. These zones are typically located in front of fire hydrants, handicap ramps and bus stops. Vehicles illegally parked in front of fire hydrants pose a safety hazard by causing delays in gaining access to the hydrant when it is needed. Blocked handicap ramps pose the obvious safety hazard for people with disabilities that have to traverse the curb or steps in place of the blocked ramp. In addition to causing delays on municipal bus routes, vehicles illegally parked in a bus zone also pose a safety hazard for passengers trying to load on and unload off the bus because the bus cannot stop at the appropriate location at the bus stop.
This especially impacts elderly people, or people with disabilities or injuries, that rely on public transportation. A municipal bus is typically capable of pulling up to a bus stop and "kneeling" at the curb to allow passengers easy access to the bus through the front door or the side handicap door. If an illegally parked vehicle prevents this from happening, the bus will have to stop some distance away from the curb or designated bus stop location and passengers will have to make their way to the bus. This may require people with disabilities, or other difficulties walking, to have to traverse the curb and enter the bus at a height. This process becomes even more hazardous when ice and snow are present.
Municipalities have recognized that vehicles blocking bus zones are becoming an increasing problem, especially in large cities, because of the resulting delays in the mass transit system and the safety concerns. In order to combat this problem, municipalities have increased enforcement efforts by hiring more transit and police officers to issue more citations and have increased fines for such offenses. Some municipalities have even elevated bus zone blocking to a moving rather than a parking violation. However, adding more transit and police officers requires the municipality to incur significant additional expense and has had only limited success in reducing the problem of bus zone blocking due to the large number of bus stops that need to be patrolled.
Therefore, there is a need for systems and methods to more efficiently enforce no parking zones, e.g., bus zones, and to significantly deter future illegal parking in such zones.

Parking violation recording system and method


A combination training lead and multiple animal leash comprising, a leash-forming strap having a handle at a first end thereof and having at least two branches at a second end thereof with a snap connector carried by each of the branches and including a D-ring attached to the leash-forming strap, intermediate its first and second ends, and adapted to interconnect with one of the snap connectors to form a second handle.

An animal leash is normally used for leading and controlling dogs or other animals and keeping them close to the leader and under his/her control. Such leashes may be designed for one or multiple animals. My U.S. Pat. No. 6,237,539 discloses a multiple dog leash that may be adjusted to accommodate dogs of different sizes.
Training of a dog requires greater control than is usually available through the use of a normal leash. That additional control is achieved through the use of a short lead where the dog, for example, can be reined in to walk closely beside the trainer. A short lead provides for control impulses that can be subtlety and immediately conveyed to the animal. The length of such a lead depends on the physical stature of the trainer and the size of the animal. An ordinary leash can be shortened to serve as a training leash by folding and bunching the excess length, but holding such a collection of leash material and exercising the proper control of the animal is difficult and cumbersome.
Accordingly, it is the primary object of the present invention to provide a leash that will serve its traditional purpose but at the same time be quickly and easily converted to a training leash that permits optimum control of the animal with comfort and convenience to the trainer.
Other objects, features and advantages of the present invention will become apparent upon reading a description of the invention taken in conjunction with the accompanying drawings.

Combination training lead and multiple animal leash


Disclosed is a method for producing Phalaenopsis orchid clone plants, which comprises cutting the tip of a growing root of a Phalaenopsis orchid that has been prepared under sterile conditions at a length of from 1 to 5 mm to prepare a root tip for culture having said predetermined length, cultivating said root tip in a PLB-inducing medium under sterile conditions to thereby induce PLB therein, further cultivating said PLB in a propagating medium, and then re-differentiating said PLB in a re-differentiation medium. The method is practicable and stably given PLB of Phalaenopsis orchids.

Phalaenopsis attract a great deal of public attention. For cultivation of plants, recently, mass-production of plants through clonal propagation is being in full flood. To the induction of protocorm-like bodies (PLB) that are in the initial stage for the production of clonal plants, at present, applied are conventional leaf segment culture and also other spike-axillary bud culture and root tip culture (M. Tanaka, 1987, Studies on the Clonal Propagation of Phalaenopsis through in-vitro Culture, Memoirs of Faculty of Agriculture, Kagawa University, No. 49; 1-85; S. Ichihashi, 1992, Micropropagation of Phalaenopsis through the Culture of Lateral Buds from Young Flower Stalks, Lindleyana, 7(4): 208-215; M. Kobayashi, M. Komatsuda & S. Yoneuchi, 1990, Studies on the vegetative propagation of Phalaenopsis through root tip culture, J. J. Soc. Hort. Sci., 63(suppl.2); 664-671).
However, in the process of the induction of PLB through such known root tip culture (M. Kobayashi, M. Komatsuda & S. Yoneuchi, 1990, Studies on the vegetative propagation of Phalaenopsis through root tip culture, J. J. Soc. Hort. Sci., 63(suppl.2); 664-671) or any other culture, the degree of the intended induction is often low or, as the case may be, no induction is attained for some varieties, hybrids and materials.
Because of such unsure induction of PLB, mass-production of plants through clonal propagation could not apply to some varieties and hybrids of Phalaenopsis. Therefore, in order to improve the efficiency in the induction of PLB, it is necessary to establish an effective method of initial culture capable of overcoming the difference in varieties and hybrids and the difference in materials.
The reasons for such unsure induction of PLB in known root tip culture are believed to be essentially that the surface of the meristematic tissue of a root tip, which is a material of a PLB-forming source, will be often damaged while being sterilized, and that said tissue could not satisfactorily display its ability for cell division due to conditions and methods unsuitable for cultivating it thereby resulting in that its ability to form PLB is lowered.

Method for producing phalaenosis clone plants through root tip culture


A soot blower assembly having a horizontally elongate steam supply tube disposed in cantilevered relationship and having a steam discharge opening at the free end, and a horizontally elongate steam discharge lance telescoped axially over the supply tube. The lance has a rear support hub which exteriorly surrounds the steam supply tube, and a seal-bearing arrangement is mounted within the hub for cooperation with the steam supply tube to permit the lance to move both axially and rotatably relative to the steam supply tube. The seal-bearing arrangement includes an axially elongate bearing sleeve which is mounted on the hub and has an inner bearing surface for rotative bearing engagement with the steam tube. This bearing sleeve is preferably constructed of bronze of similar bearing material, and is axially split to compensate for temperature-induced variations. A lip seal assembly cooperates between the steam supply tube and the hub axially rearwardly of the bearing sleeve for creating a sealed engagement with the periphery of the steam supply tube.

In fossil-fuel burning power plants and similar boilers, soot deposits collect on the heat transfer pipes, and buildup of such deposits can seriously interfere with proper heat transfer efficiency. Such power plants and boilers are provided with soot blower assemblies for permitting cleaning of soot from the exterior of the heat transfer pipes. Such assemblies typically include an elongate hollow tubular lance which has steam discharge nozzles adjacent the leading end thereof, which lance is moved inwardly into the heat transfer chamber in generally parallel relationship to one or more adjacent heat transfer pipes so as to eject steam against these pipes to dislodge the soot therefrom. The lance in turn is rotatably and axially slidably supported on an elongated and cantilevered stationary steam supply pipe which projects coaxially into the lance, and a packing assembly cooperates between the lance and steam supply pipe to create a sealed relationship therebetween, while at the same time permitting the lance to be axially and rotatably advanced into the heat exchange chamber when removal of soot is desired. Each power plant or boiler typically has a large number of such soot removal devices associated therewith, and the lance of each device must be cantilevered inwardly and moved through a significant extent which may be as much as 40 feet.
At present, conventional soot blowers employs a plurality of packings disposed axially adjacent one another for cooperation between the lance and steam supply pipe. These packings are able to withstand the high temperature of the steam, which is typically supplied at a temperature of about 600.degree. F. However, inasmuch as the soot blowers are activated only periodically, such as once over a several hour interval, the overall soot blower experiences severe differential thermal expansion characteristics when activated due to significant temperature changes when the superheated steam is supplied thereto. This thus makes sealing of the lance to the steam supply tube, while still permitting relative axial and rotary movement therebetween, difficult. While packings have been used with at least limited success, nevertheless packings do possess disadvantages. It has been observed that use of packings in this environment requires constant adjustment in the packing compression in order to achieve a proper seal while still permitting relative movement between the lance and steam supply pipe. If the packing compression is too little, then leakage occurs, and conversely if the compression is too high, then proper movement of the lance is difficult to achieve. The packings have also been observed to cause undesirable wear on the steam supply tube in view of the significant compression required of the packing in order to achieve a desired seal. Even though the use of packings in this environment has possessed recognized disadvantages, nevertheless such packings have been used for many years and continue to be used in this environment in view of the lack of other satisfactory solutions.
Accordingly, it is an object of this invention to provide an improved seal-bearing structure for cooperation in a soot blower assembly, which seal-bearing structure permits elimination of the conventional packings and hence overcomes the disadvantages associated with the prior art structures.
In the present invention, there is provided an improved soot blower assembly wherein an elongated steam discharge lance exteriorly surrounds and is both axially and rotatably movable relative to an elongate cantilevered steam supply tube. The rearward end of the lance includes a tubular housing which supports the lance for axial displacement along a frame, and the rear of the lance is also provided with a seal-bearing arrangement which externally surrounds and cooperates with the cantilevered steam supply tube to concentrically support the steam supply tube within the lance as the latter is displace axially therealong, while at the same time providing a steam-retaining seal therebetween. This seal-bearing arrangement includes a generally elongate bearing sleeve which is disposed annularly between the lance and supply tube. This elongate bearing sleeve, when the soot blower is deactivated so as to be at normal temperature, has an inner annular clearance where it surrounds the supply tube. The elongate sleeve bearing is also provided with a split extending axially and radially therethrough. The sleeve bearing is preferably of bronze or similar bearing material so as to not require lubrication. This bearing sleeve, due to the different thermal expansions and the rapid heat up of the supply tube when steam is supplied thereto, enables the supply tube to expand into engagement with the sleeve bearing, and expansion of the latter is compensated for by the axial slit, whereby the sleeve bearing maintains a rotatable running clearance with the steam supply tube due to permissible circumferential expansion of the split bearing relative to the surrounding lance. The split bearing is disposed on the upstream pressurized steam side of a seal which includes at least one, and preferably two, serially disposed rod-type wiper seals disposed in sealing engagement with the steam supply tube and with a surrounding insert member which is fixed within the lance.
With the improved soot blower assembly of this invention, as briefly described above, the lance can be axially extended and simultaneously slowly rotated about the cantilevered steam supply tube over long axial distances, and as the lance is extended forwardly during the soot blowing operation, the seal-bearing arrangement rotatably and axially bearingly supports and sealingly engages the cantilevered steam supply tube so as to effectively maintain the latter concentric within the lance, particularly when approaching the cantilevered free end of the steam supply tube, so as to overcome tube droop and hence permit successful performance of the soot blowing operation.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.


Disclosed herein is an amplification method, an optical glass amplifier, a laser based on the amplifier and an amplification optical communication system, all based on a limited length of a single-mode glass fiber made from glass having phonon energy of less than about 350 cm.sup.-1 and doped with dysprosium. The glass includes 0.1-30 mol % germanium, 0-40 mol % arsenic, 0.01-20 mol % X, 0.01-20 mol % Y, and 0.001-2 weight % dysprosium, wherein X is selected from the group consisting of gallium, indium and mixtures thereof selenium; and wherein Y is selected from the group consisting of selenium, and mixtures of selenium and up to 50% of sulfur. The system includes a coupler, a silica-based signal fiber carrying the optical signal that is to be amplified in communication with said coupling means, a pump light source in communication with the coupler, an amplifier in communication with the coupler at one end and another silica-based fiber joined to the amplifier at its other end. The method includes the steps of introducing the optical signal to be amplified into the coupler, introducing a pump optical signal into the coupling means, combining the optical signal and the pump optical signal, introducing the combined optical signal into the amplifier and amplifying the optical signal by exciting the electrons in dysprosium so they emit at about 1.3 .mu.m.

1. Field of Invention
This invention pertains to amplification of an optical signal with a waveguide made from glass having phonon energy of less than about 350 cm.sup.-1 and doped with dysprosium.
2. Description of Prior Art
There is a need for 1.3 .mu.m fiber optic amplifiers for telecommunications to enable high speed optical networking in local area networks for both military and commercial applications. Currently, a large proportion of the embedded plant is at 1.3 .mu.m. Transoceanic submarine links utilize erbium doped fiber amplifiers based on silica fibers operating at 1.55 .mu.m which corresponds to the wavelength of minimum loss in silica. However, the local area network applications require amplifiers at 1.3 .mu.m for high bandwidth applications since this corresponds to the wavelength of zero dispersion in silica.
Currently, the telecommunication industry uses bulky electronic repeaters at 1.3 .mu.m which convert the optical signal into an electronic signal which is amplified and then converted back into an optical signal via diode lasers. These repeaters are cumbersome, are detectable, and require high-cost maintenance. The telecom industry is actively involved in the development of compact fiber optic based amplifiers.
Silica fiber is not an appropriate host for 1.3 .mu.m emission since the rare earth ions of praseodymium and dysprosium undergo multiphonon relaxation from their respective excited state, i. e., from .sup.1 G.sub.4 to .sup.3 F.sub.3 in praseodymium and from .sup.6 H.sub.9/2, .sup.6 F.sub.11/2 to .sup.6 H.sub.11/2 in dysprosium. This effectively quenches the 1.3 .mu.m emission rendering the device impractical. The phonon energy of silica is about 1100 cm.sup.-1.
Much work has been performed in doping rare earth ions in lower phonon energy glasses such as fluoride glasses with phonon energies of greater than 500 cm.sup.-1, and more recently, in sulfide glasses with phonon energies of greater than 400 cm.sup.-1. The work in fluoride fibers has actually led to a commercial product, i. e., a praseodymium doped fiber amplifier operating at 1.3 .mu.m. However, this product has not found widespread acceptance since the quantum efficiency is very low at less than 5%, signal gain is small at about 0.08 dB/mW, and the pump power requirements at 1.02 .mu.m are extremely high at about 440 mW. The latter property leads to short diode lifetimes which inevitably adds to the cost and lack of reliability of the system. Furthermore, the chemical durability of fluoride glasses is poor compared to silica based fibers which have to meet long term reliability of greater than 15 years. All these characteristics contribute to the unfavorable response by the telecom industry to the use of praseodymium doped fluoride fiber amplifiers. While praseodymium does not work well in fluoride glasses, the 1.3 .mu.m emission of dysprosium is even weaker in these glasses since it is multiphonon quenched.
On the other hand, sulfide glasses possess lower phonon energies than fluoride glasses and so consequently, have been doped with praseodymium. The glass compositions cited in the literature are based on Ga-La-S and Ge-Ga-S. The expected gain is proportional to the value of .sigma..sub.e .tau. which represents the product of the measured emission cross-section (.sigma..sub.e) and the lifetime of the excited state (.tau.). The values of .sigma..sub.e .tau. obtained for Ga-La-S, Ge-Ga-S and the fluoride glasses doped with praseodymium are 250, 479 and 39 (.times.10.sup.-26 cm.sup.2 s), respectively. This indicates that the expected gain is about an order of magnitude higher than that obtained for praseodymium doped fluorides for the same pump power. In other words, the praseodymium doped sulfide glasses require about 10 times less pump power for the same gain. Quenching from the .sup.1 G.sub.4 level in praseodymium still occurs to the .sup.3 F.sub.3 level but to a lesser extent so that the quantum efficiency for the 1.3 .mu.m emission is higher at about 30%. However, using the rate equation model for a 4-level system, it would appear that very low fiber losses are necessary in order to realize a practical amplifier device. For example, a loss of about 1 dB/m is required at around 1.3 .mu.m to attain a gain of greater than 20 dB using a fiber length of over 10 meters containing 500 ppm of praseodymium. To date, the lowest loss reported in a multimode sulfide fiber over several meter lengths is only about 0.5 dB/m and occurs at longer wavelengths, typically at wavelengths greater than 2 .mu.m. The loss at 1.3 .mu.m is closer to 1 dB/m, at best. The problem is further highlighted by the fact that a single mode fiber of about 2 .mu.m core diameter is needed for a fiber amplifier. The lowest loss reported to-date for a single mode sulfide fiber is greater than 1 dB/m, measured on a 1 meter length at long wavelengths exceeding 2 .mu.m. Practical realization of a fiber amplifier at 1.3 .mu.m requires 10-20 meter lengths of low loss praseodymium doped sulfide fiber which is difficult and cost intensive task to achieve.
Dysprosium has also been doped in sulfide glasses. For instance, excited state lifetime of only 38 .mu.s for dysprosium in a Ge-Ga-S glass pumped at 810 has been measured. The emission was very weak. As.sub.2 S.sub.3 glass doped with dysprosium did not show any fluorescence at 1.3 .mu.m. More recently, Ge.sub.30 As.sub.10 S.sub.60 and Ge.sub.25 Ga.sub.5 S.sub.70 glasses doped with 0.2-0.5 weight percent dysprosium showed very weak fluorescence at 1.3 .mu.m when pumping at about 808 nm. In another example, fluorescence was not observed in As.sub.2 S.sub.3 glass containing 0.1 weight percent dysprosium although in As.sub.2 S.sub.3 glass containing 1.7 mole percent iodine, in Ge.sub.30 As.sub.10 S.sub.60 glass, in Ge.sub.25 Ga.sub.5 S.sub.70 glass and in Ge.sub.35 S.sub.56.5 I.sub.8.5 a weak fluorescence was observed at 1.3 .mu.m with a measured lifetime of less than 38 .mu.s, leading to a quantum efficiency of less than 20%. Ga-La-S glass has been doped with 500 ppm of dysprosium and fluorescence was observed at 1.3 .mu.m with a measured lifetime of 59 .mu.s, leading to a quantum efficiency of about 29%. This was achieved by pumping at 815 nm as well as 914 nm.
It appears that to date, the best rare earth ion dopant is praseodymium in a sulfide host for a potential fiber amplifier at 1.3 .mu.m for telecommunications. However, the weak absorption cross-section for the .sup.1 G.sub.4 level necessitates the use of longer fiber lengths and, therefore, low fiber losses are absolutely critical to enable this application.
Those skilled in the art have ruled out the use of lower phonon energy hosts or glasses such as selenide glasses, whose phonon energies are less than about 350 cm.sup.-1, doped with praseodymium and dysprosium for potential 1.3 .mu.m fiber optic amplifiers. This is because these ions are typically pumped at 1.02 .mu.m and 0.815 .mu.m (and 0.915 .mu.m ), respectively. It is well known that the electronic edge, i.e., the short wavelength edge, is shifted to longer wavelengths in selenide glass hosts and so absorption by the electronic edge would be significant at the pump wavelengths used thus far, namely 1.02 .mu.m in praseodymium and 0.815 .mu.m or 0.914 .mu.m in dysprosium. In addition, these small band gap materials exhibit a weak absorption tail which extends into the infrared. Consequently, it is widely believed that the emission at 1.3 .mu.m would also be appreciably absorbed by the selenide host matrix, thereby making such amplifiers impractical.
In addition to the negative sentiments regarding the optical performance at 1.3 .mu.m, it is widely believed that low phonon energy hosts, such as the selenide glasses (<350 cm.sup.-1) possess poor solubility of rare earth ions which leads to clustering and crystallization, especially during fiber drawing. This has a detrimental effect on the fluorescence at 1.3 .mu.m. Such clustering has been attributed to the lack of an appropriate site for the rare earth ions which arises from the difference in bonding character between the glass forming selenides and the rare earth precursors. In other words, the solubility of rare earths in low phonon energy selenide glasses is low since the glass structure consists of predominantly covalent bonding character while the rare earths prefer to form predominantly ionic bonds. Also, the refractory nature of rare earth selenides makes it harder for them to dissolve in the glass melt.
Optical waveguides come in different shapes and sizes, and examples include fibers and planar waveguides. Fibers are usually of circular cross-section and possess diameters of tens to hundreds of microns and lengths typically of a few meters to many kilometers. Planar waveguides typically possess thicknesses from a few microns to hundreds of microns and lengths from a few millimeters to several centimeters. The advantages of planar waveguides are that they are small and compact whereas fibers enable remote/long distance applications. Fiber waveguides are drawn from core/clad preforms or using crucible melting techniques whereas planar waveguides are made by depositing glass on a substrate and then using ion exchange or photochemistry to generate the core/clad waveguide structure.

Amplification by means of dysprosium doped low phonon energy glass waveguides

The United States of America as represented by the Secretary of the Navy


A convergence terminal, including a set top box unit, a home gateway unit, a main control board and an interconnection backplane, where the main control board establishes a communication connection with each of a multimedia device and an Internet access device, the main control board connects, in a communication manner, to each of the set top box unit and the home gateway unit through the interconnection backplane. In the present invention, an objective of implementing that a television service and an Internet access service are separately provided through a service terminal is achieved, thereby reducing the number of service terminals used by a user for enjoying different services, and also reducing frequent wiring operations of the user on connection wires for inward connection and outward connection.

With the continuous development of sciences and technologies, demands of a consumer in the home field are also continuously expanded, such as, enjoying Internet access pleasures brought by a home gateway (HGW) of a home local area network, and watching a digital television program (such as Digital Video Broadcasting (DVB)) on a television set through a set top box (STB).
In an existing common practice, a home gateway and a set top box each have an independent access software platform operating system, and their respective services are also isolated from each other.
The prior art has the following disadvantages: In the prior art, a home gateway and a set top box each have an independent access software platform operating system, and their respective services are also isolated from each other, so when a consumer needs to enjoy different services, the consumer needs to use a plurality of different service terminals, and then separately performs independent operations and use, which increase frequent operations of the consumer on the plurality of service terminals.

Methods and apparatuses for providing multi-service via a signal convergence terminal


A method of controlling an aluminum reduction cell including the following steps:                maintaining alumina concentration within preset limits by alternating base, underfeed and overfeed modes; measuring cell voltage and potline amperage; calculating current normalized voltage value and a rate of changing thereof in time; comparing the calculated values of the normalized voltage with preset values thereof and correcting anode-cathode distance when passing from the base mode to the overfeed or underfeed modes; and measuring a number of alumina feed doses in the underfeed mode and overfeed mode over a time period sufficient for the alumina to dissolve.

In order to produce aluminum, aluminum oxide (alumina) is molten at high temperature in a bath comprising cryolite and other fluorine salts. Molten aluminum oxide decomposes in an electrolytic cell under the action of direct current passing through the bath. The pure aluminum deposits on the cathodes, while the oxygen oxidizes and consumes the anodes.
With time, the amount of alumina in the bath decreases. When the alumina concentration in the bath decreases to 0.5-1.5%, a special mode of cell operation occurs known as the anode effect, which is accompanied by low level of the cell performance.
During operation, to maintain satisfactory cell performance new doses of alumina are added to the melt at regular time intervals or alternatively continuously supplying alumina by alumina feeding mechanisms (AF mechanisms).
It is known that in order to efficiently control the electrolytic process it is necessary to stabilize the power conditions and material balance thereof. Among the objects of the method of controlling electrolysis of aluminum is achieving the best cell performance, and for this purpose, establishing optimum conditions for dissolution of alumina and stabilizing the alumina concentration under variable process parameters, quality of raw materials, etc. Among known methods of process control for aluminum cell operation are the methods which are based on the normalized voltage and the direction of anode movement characteristics
A method of automatic control of an aluminum cell comprises the steps of measuring cell voltage and cell current, calculating current values of the cell resistance, establishing the baseline value of resistance or normalized voltage before addition of each dose of alumina. The minimum value of normalized voltage Unormmin is used as a process control set point. In case of discrepancy between the normalized voltage Unorm and current value of normalized voltage Unorm rcur., the anode is moved and all such movements are recorded. When the anode movements are mostly in the downward direction, the concentration value of the cell is set as decreasing. When anode movements are mostly in the upwards direction, the concentration value is set as increasing. When anode movements are rare, immediately after works and before the next handling of the cell, the concentration value is set as normal. To achieve normal conditions for alumina concentration in the bath when the concentration values are increased and decreased, the alumina loading mode is corrected by addition of alumina or by other actions (See RU, 2148108).
Among major drawbacks of these prior art methods is that they do not allow timely feedback of the cell disturbances which result from changes in the electrolytic characteristics and the overall quality of raw materials. This ultimately reduces operational efficiency.
Among known methods of controlling an aluminum cell are the normalized voltage method and the mathematical modeling method. These methods apply the techniques of controlling an aluminum cell by periodic feeding of alumina into the cell, measuring the cell voltage and line current, calculating bath resistance across the anode-cathode space, determining the average value of these parameters and determining concentration of the alumina in the bath by a mathematical model, and calculating the variation of alumina feeding rate into a cell by deviation of the calculated concentration from the set value. (See Russian Patent Documents RU 2106435 and RU 2204629).
The major disadvantage of these methods is the inherent inaccuracy of the alumina concentration due to inadequacy of responsiveness of the used model to many important operational characteristics, including changes in bath temperature, quality of alumina, etc. This results in low level of stability and high fluctuations of alumina concentration in the bath.
The known methods of controlling aluminum cells further include equipping aluminum cells with point-feeding system controlled by normalized voltage and derivatives thereof. For example, a control method is utilized which maintains the temperature conditions of a cell by alternating overfeed and underfeed modes and adjusting the anode-cathode distance and alumina concentration within preset values. The method comprises measurement of cell voltage and line current, calculation of current value of normalized voltage Unorm and the rate of changes thereof in time dUnorm/dt, comparison of calculated values with preset values and making a decision to adjust the anode-cathode distance and shifting from overfeed to underfeed modes or vice versa on the basis of such comparison (See Russian Patent Documents SU 1724713 and RU 2113552).
These methods are capable of maintaining the alumina concentration in the bath in the technologically acceptable range between 2 and 5%. However, in application of these methods the feeding mode criteria, such as a preset time of overfeed mode and maximum voltage of underfeed mode do not provide the required accuracy for maintaining the alumina concentration. In these methods only the rough estimates of dUnorm/dt (positive/negative) are utilized.
It appears that the most relevant prior art method to the present invention is that of controlling aluminum production cells by maintain the temperature levels through alternating the overfeed and underfeed modes and adjusting the anode-cathode distance and adjusting the alumina concentration within preset values. There are the following steps in this prior art method: measuring the cell voltage and line current, calculating the current value of normalized voltage Unorm and the rate of its changes over time dUnorm/dt, comparing the calculated values with the preset values and making a decision concerning the adjustment of the anode-cathode distance, so as to shift the method either to overfeed or underfeed modes. This occurs on the basis of comparison of the variation rate of normalized voltage value dUnorm/dt>G1 over time. Transition from the overfeed mode to underfeed mode occurs when the normalized voltage variation rate over time is dUnorm/dt<G2, where G1 and G2 are the threshold values of normalized voltage variation rate which are established experimentally. Furthermore, the anode-cathode distance is adjusted upon transition from the overfeed mode to underfeed mode, provided: |Unorm−Uo|>ΔU, where U0 is the nominal value of normalized voltage, ΔU is predetermined by the process requirements a zone of insensitivity (See Russian Patent Document RU 2189403).
In the prior art method, the base mode is the mode which takes place at the moment of transition from the overfeed mode to the underfeed mode. The base mode time is calculated based on the cell output (daily alumina doses). In this mode the pseudo resistance of the cell is almost constant. Therefore, at this specific time, the anode beam position is corrected.
Among major drawbacks of this prior art method is that it does not take into account changes in the alumina concentration in the bath resulting from changes in the quality of raw materials, electrolytic parameters, and characteristics of the alumina feeding device, i.e. alumina dose mass. Furthermore, the rate of dUnorm/dt responds only to the concentration of alumina dissolved within the bath. When the rate of alumina dissolution decreases during the high level massive alumina feed (i.e. the overfeed mode), the dUnorm/dt rate is of considerable importance, as it indicates about the necessity to add alumina into the pot. This occurs even though such addition is not required. Thus, the alumina point-feeding system control often responds in the way which is opposite to the required one. Thus, in highly undesirable fashion, this prior art system carries out massive loading of alumina during the overfeed mode. In response the pot becomes overburdened with alumina, and alumina muck is formed at the bottom of the cell. As a result, the actual fluctuations of alumina concentration in the bath become impermissibly high. This causes increased frequency of the anode effects and increased frequency of turning on the motors adapted to move the anode carbon (i.e. squeezing of the pot). This increases the number and severity of process malfunctions and causes deterioration of the cell performance. The latter results in the increase of power consumption, the decrease of cell output, and the increase in labor to eliminate the process problems.
Inability to obtaining the desired technological results arises because the algorithm of the prior art method does not take into accounts variables such as the changes in the quality of raw materials, the rate of alumina dissolution, and the characteristics of electrolysis and the point-feeding system.

Method of controlling an aluminum cell with variable alumina dissolution rate