The invention is a system for digital watermarking that operates on a conventional digital video stream to etch, on hand, and read, on the other hand, digital watermarks in the stream that do not visibly interfere with the video content. A system according to the invention operates on digital data that has been transformed into the spatial-frequency domain, using inter-block differences between spatial-frequency coefficients to encode the bits of a digital watermark. Using the principles of the invention, it is possible to encode multiple watermark bits between two adjacent blocks, thus providing higher watermark data rates relative to underlying video content.

1. Field of the Invention
This application relates to the field of digital multimedia and more particularly to the field of watermarking digital multimedia content.
2. Description of Related Art
Enforcing ownership rights in digital content may be difficult due to the relative ease with which the content can be reproduced and distributed. Secure communication provides one form of protection. Encryption may prevent outsiders from viewing a video sequence, but once the video stream has been decrypted, there is no protection against manipulation and redistribution of the stream. Further, where widespread distribution of multimedia content is desired, key-management for a typical public key encryption scheme becomes cumbersome. In addition, encryption may require error-free communications, which may not be available in all networks, particularly in a wireless network. Thus, there is an interest in supplemental security methods for multimedia content.
Another form of protection is provided by a message authentication code (xe2x80x9cMACxe2x80x9d) that is attached to digital content. For example, origination information may appear within a message field appended to digital content. However, this type of add-on authentication is easily identified and removed. A more resilient MAC system is provided by digital watermarking.
Digital watermarking is a technique for hiding an identification of origin in a digital media stream. A digital watermark is actually embedded in the media stream in a way that inhibits removal without destroying the underlying content. The watermark may also be folded into the original data in a manner that is imperceptible to the listener/viewer. When such watermarked digital content is distributed on-line, or recorded on a disk, the origination data travels with it, and allows the originator to demonstrate the source of the content. Digital watermarking also identifies tampering, since any manipulation of a sequence will result in an invalid watermark.
One technique for encoding multimedia content is detailed in the well-known Moving Picture Experts Group (xe2x80x9cMPEGxe2x80x9d) 2 standard. MPEG-2 is based upon a process of breaking an image frame up into fixed-size blocks, converting the blocks to luminance/chrominance data, transforming the blocks using a discrete cosine transform (xe2x80x9cDCTxe2x80x9d), and quantizing the transformed data. The resulting xe2x80x9cI framexe2x80x9d includes Y blocks for luminance (four in MPEG-2""s main level at main profile) and C blocks for chrominance (two in the main level at main profile) for each block of the frame. Each block contains a matrix of coefficients calculated from a Y or C block using the DCT. This step compresses data by removing so-called spatial redundancies, which may loosely be considered as similar-looking content in different areas of a block. Variable-length coding is then used to compress long runs of zeroes that are typical of high spatial-frequency coefficients. Still further compression is achieved by coding consecutive frames into xe2x80x9cP framesxe2x80x9d (predictive) and xe2x80x9cB framesxe2x80x9d (bi-directional), which only include information describing changes relative to neighboring chronological frames.
One known technique for watermarking such an MPEG-2 video stream is to use the DC coefficients of the Y blocks in each I frame of the MPEG-2 stream to effectively form a parity bit. According to this technique, the median DC coefficient of each sequential group of three Y blocks is forced to be always even or odd, depending on the watermark bit being encoded. This technique has a minimal impact on image quality and is relatively simple to implement. However, as a significant disadvantage thereof, this technique is not particularly robust. In many instances, only one out of every fifteen frames of an MPEG-2 video stream is an I frame, only two out of three blocks in an I frame is a Y block, and only one out of every three Y blocks is coded for watermarking. In those instances, very few bits of the overall bit stream are actually used for a watermark. Thus a relatively small amount of data corruption from bit errors in the data channel can effectively erase a watermark. At the same time, it is less likely that minor, intentional alterations will be detected.
There remains a need for a digital watermarking scheme that provides high watermark bit rates (relative to the overlying digital content) while remaining imperceptible to content users. A successful watermark would retain its signature in the presence of an error-prone data channel, and would correctly alert a watermark user to data tampering.
In accordance with the principles of the invention, there is provided digital watermarking that operates on a conventional digital video stream to etch, on hand, and read, on the other hand, digital watermarks in the stream that do not visibly interfere with the video content. The technique operates on digital data that has been transformed into the spatial-frequency domain, using inter-block differences between spatial-frequency coefficients to encode the bits of a digital watermark. According to the principles of the invention, it is possible to encode multiple watermark bits between two adjacent blocks, thus providing higher watermark data rates relative to underlying video content.
In one aspect, there is provided etching a digital watermark by: providing a watermark bit; providing a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; and setting a first difference to a predetermined value according to the watermark bit, the first difference being a difference between a first coefficient of the first block and a corresponding first coefficient of the second block.
This aspect may further include repeating the above for a plurality of consecutive watermark bits and a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block. This aspect may also include setting the first difference to a predetermined value according to the watermark bit further includes forcing the first difference to a first level if the watermark bit is a one, and forcing the first difference to a second level if the watermark bit is a zero. In this aspect, the first level may be a binary even level and the second level may be a binary odd level. Setting the first difference to a binary even level may further include adding a quantization level to the corresponding first coefficient if the first difference is odd, and wherein setting the first difference to a binary odd level further includes adding a quantization level to the corresponding first coefficient if the first difference is even.
This aspect may further include: providing a second watermark bit; and setting a second difference to a predetermined value according to the second watermark bit, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block. The plurality of consecutive watermark bits may include an encrypted watermark. The digital media stream may include a Motion Picture Expert Group video stream, the first coefficient being a DC coefficient. The digital media stream may include a Motion Picture Expert Group video stream, the first coefficient being an AC coefficient.
In a different aspect, there is provided reading a digital watermark by: receiving a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; determining a first difference between a first coefficient of the first block and a corresponding first coefficient of the second block; and determining a watermark bit, the watermark bit having a predetermined value according to the first difference.
This aspect may further include repeating the above for a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block, thereby determining a plurality of consecutive watermark bits. The predetermined value may be a one if the first difference has a first level, and the predetermined value may be a zero if the first difference has a second level. The first level may be a binary even level and the second level may be a binary odd level.
This aspect may further include determining a second difference between a second coefficient of the first block and a corresponding second coefficient of the second block, and determining a second watermark bit, the second watermark bit having a second predetermined value according to the second difference. The plurality of consecutive watermark bits may include an encrypted watermark. The digital media stream may include a Motion Picture Expert Group video stream and the first coefficient is a DC coefficient. The digital media stream may include a Motion Picture Expert Group video stream and the first coefficient is an AC coefficient.
In a different aspect, there is provided a system for etching a digital watermark that includes means for providing a watermark bit; means for providing a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; means for either setting a first difference to a first level if the watermark bit is a one, or setting the first difference to a second level if the watermark bit is a zero, the first difference being a difference between a first coefficient of the first block and a corresponding first coefficient of the second block; and means for providing a plurality of consecutive watermark bits and a plurality of consecutive blocks to the above means, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block.
In this aspect, the first level may be a binary even level and the second level may be a binary odd level. This aspect may further include means for providing a second watermark bit; and means for either setting a second difference to be even if the watermark bit is a one, or setting the second difference to be odd if the watermark bit is a zero, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block. There may also be provided means for encrypting the plurality of consecutive watermark bits into an encrypted watermark. There may also be provided means for variable-length decoding the first plurality of coefficients and the second plurality of coefficients before applying the determining means and the setting means, and means for variable-length coding the first plurality of coefficients and the second plurality of coefficients after applying the determining means and the setting means.
In a different aspect, there may be provided a digital video encoder that includes a watermark source, the watermark source providing a plurality of watermark bits; a transform unit, the transform unit receiving a plurality of blocks of video data and performing a two-dimensional transform on each block to provide a transformed block, each transformed block including a plurality of coefficients; a quantizer, the quantizer receiving each transformed block and scaling each coefficient of each transformed block using a quantization index, thereby providing a plurality of quantized blocks; and a watermark unit, the watermark unit receiving one of the plurality of watermark bits from the watermark source, a first one of the plurality of quantized blocks, and a second one of the plurality of quantized blocks, the watermark unit encoding the one of the plurality of watermark bits by setting a difference to be even if the one of the plurality of watermark bits has a first value and setting the difference to be odd if the one of the plurality of watermark bits has a second value, the difference being a difference between a first coefficient of the first one of the plurality of quantized blocks and a corresponding first coefficient of the second one of the plurality of quantized blocks.
In this aspect, the first coefficient and the corresponding first coefficient may be DC coefficients. The first coefficient and the corresponding first coefficient may be AC coefficients. Setting the difference to be even may include adding a quantization level to the corresponding first coefficient if the difference is odd, and setting the difference to be odd may include adding a quantization level to the corresponding first coefficient if the difference is even. The plurality of quantized blocks may include a Motion Picture Expert Group video stream.
In a different aspect, there is provided a digital watermark embodied in a digital video stream carrier signal, the digital watermark comprising a plurality of watermark bits, each watermark bit having a value encoded between consecutive blocks of the digital video stream, the value being a first value when a difference between a pair of consecutive corresponding coefficients is even, and the value being a second value when the difference between the pair of consecutive corresponding coefficients is odd.
In this aspect, the first value may be one and the second value may be zero. The first value may be zero and the second value may be one. The pair of consecutive corresponding coefficients may each be DC coefficients. The pair of consecutive corresponding coefficients may each be AC coefficients.
In a different aspect, there is provided a computer program product for etching a digital watermark, embodied in machine executable code for performing the following steps: providing a watermark bit; providing a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; and setting a first difference to a predetermined value according to the watermark bit, the first difference being a difference between a first coefficient of the first block and a corresponding first coefficient of the second block.
In this aspect, there may be further provided machine executable code for repeating the above for a plurality of consecutive watermark bits and a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block. Setting the first difference to a predetermined value according to the watermark bit may further include setting the first difference to a first level if the watermark bit is a one, and setting the first difference to a second level if the watermark bit is a zero. The first level may be a binary even level and the second level may be a binary odd level. Setting the first difference to a binary even level may further include adding a quantization level to the corresponding first coefficient if the first difference is odd, and setting the first difference to a binary odd level may further include adding a quantization level to the corresponding first coefficient if the first difference is even. The computer program product may further comprise machine executable code for providing a second watermark bit; and setting a second difference to a predetermined value according to the second watermark bit, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block. The plurality of consecutive watermark bits may include an encrypted watermark.
The digital media stream may includes a Motion Picture Expert Group video stream, the first coefficient being a DC coefficient. The digital media stream may include a Motion Picture Expert Group video stream, the first coefficient being an AC coefficient.


A bi-directional flow valve for use in regulating flow of pressurized fluids in surgical instruments is disclosed. The valve comprises a valve body having an axial bore of variable radius, a plunger axially and slidably mounted within the bore of the valve body, a flange provided on the plunger for circumferentially engaging the bore at its narrowest point, a spring means for urging the flange against the bore at its narrowest point, and seal means to seal the gap between the plunger and the bore, and displacement means to move the plunger and flange out of contact with the bore so that fluid may pass through the bore and thus through the valve.

Over the past several years, laparoscopy has become an important means for conducting minimally invasive surgery. Because trauma to the patient is greatly reduced, as compared with traditional invasive surgical techniques, patient discomfort and post-operative recovery time are greatly reduced.
Laparoscopic surgery utilizes elongated, hollow tubes called cannulae both to deliver and remove fluids from the site to be operated upon. In the case of fluid delivery, it is highly desirable to control both the flow rate and the force with which the fluid is carried to the surgical site. A variety of valves have been employed to achieve this desired control.
Valves currently used in conjunction with laparoscopic surgery comprise two basic styles, one employing a hole through the piston through which fluid passes, the other employing an hourglass-style piston with the fluid traversing around the waist of the hourglass.
Existing valve styles employ a metal housing surrounding a metal piston that moves up and down through the housing. The valve components are manufactured with close mechanical tolerances and require extensive lubrication in order to avoid jamming or sticking during operation. Such valves lack any sealing means, other than the seal provided by the lubricated contact of the piston with the valve housing.
Recently, laparoscopic techniques have come to depend upon the delivery of fluids at relatively high pressure. Known valves, such as those described, suffer several drawbacks when used to deliver fluids under high pressure. First, and most importantly, such valves leak extensively because there are no seals. Second, with some types of metallic valves, such as those fabricated from brass, the metallic surfaces of the piston and the housing oxidize to form extensive residue. Accumulated residue often causes the valves to stick or "freeze up". Finally, because the valve components are tooled to such narrow tolerances, they must be meticulously cleaned and relubricated after each use. Failure to carry out such procedures also results in valve failure.
Given the limitations of valves currently used for surgical applications, it is desirable to have a valve that is simple, easy to disassemble and clean, reliable, and would operate leak free under high pressures and with pressure gradients in either direction.


Apparatus designed to mix and/or aerate waste water by floating on the surface of the water, comprising a motor (2) having a shaft (3) oriented downwards and driving a propeller (4), a guide tube (5), a water-deflecting device (6) and at least two floats, an upper float (9) and a lower float (10), mounted apart one above the other and arranged concentrically relative to the axis of the motor (2), which allow the apparatus (1) to be positioned between two limiting levels relative to the surface of the water:. a lower level where only the upper float (9) is situated on the surface of the water and in which the apparatus is suitable for use as a mixer and PA1 a upper level where only the lower float (10) is operational and in which the apparatus is suitable for use as an aerator.

This kind of apparatus comprises in general an electric motor, the shaft of which is oriented downwards and which drives a propeller capable of propelling the water, a lower guide pipe or cone, a stabilizer, an upper deflector and at least one float designed to keep the apparatus on the surface of the water.
Depending on the direction of rotation of the propeller, the apparatus can be used either as a mixer by sucking the water which is situated at the surface of the tank towards the propeller which propels this water towards the bottom of the tank, or as an aerator by sucking the water from the bottom of the tank and propelling it onto the surface of the water.
It will be understood immediately that, in order to perform these two different operations, it is necessary to be able to adjust the immersion level of the apparatus relative to the surface of the water in order to obtain high degrees of efficiency.
Floating mixers or aerators designed for the treatment of waste water are known in a general way. Thus, for example, Belgian Patent BE 884,216 describes a device for mixing gas with a liquid, or vice versa, and also for degassing a liquid, consisting of a power generator driving a shaft equipped with a propeller which is situated below the surface of the water, while a blade wheel is fixed to the part of the shaft situated above the propeller.
A similar apparatus has been described in Patent BE 893,687 and is characterized by the fact that the propeller and the blade wheel form part of a single combined rotor body, the lower part of which consists of an axial-propeller pump and the upper part of which consists of a centrifugal rotor.
For the treatment of waste water, it is however, advantageous to saturate the water periodically and alternately with oxygen or to mix the former simply without special addition of oxygen.
In this way, it is possible for the processes, which are known to any specialist and consist in the alternate nitrification and denitrification processes, to be controlled more easily while keeping them under supervision. The consequence of this is that the total quantity of oxygen which is necessary for the treatment of the waste water can be substantially reduced.
Document DE-A-2,119,638 discloses a surface aerator fitted with a float comprising two independent chambers, one of which is connected to a liquid or air supply pipe so as to be able to fill or empty one chamber of the float, thus allowing a height adjustment of the assembly. This height adjustment relative to the water level is, however, exclusively linked to the adjustment of the water throughput and of the oxygen supply required.
Patent AT-PS-378,167 describes a floating surface aerator which can be transformed into a mixer by controlled immersion of the assembly. In order to do this, it is fitted with a device for adjusting the immersion level which employs a float mounted in the central position which can be filled with ballast as desired and which is stabilized by at least one additional float a considerable distance away and connected in a flexible manner to cross-members, for example by means of a chain. The result is then that, if the immersion is sufficient, the float or floats situated apart have a stabilizing effect on the mixer/aerator via the cross-member and the taut chain.
An apparatus of this kind has, however, serious disadvantages.
Namely, the separated additional floats always float on the surface of the water and therefore obstruct the ejection path of the water which is distributed over the surface of the water during the aeration phase. The result is a large decrease in the efficiency and also the stability owing to the appearance of uncontrolled eddies around the floats. Moreover, the addition of cross-members, chains and additional separated floats makes the apparatus more costly, mechanically more sensitive and more difficult to maintain.
If the mixer-aerator is partially submerged by filling the central float with ballast, the device is then stabilized only from the moment when the separated floats are able to exert a force on the cross-members, that is to say from the moment when the chain for joining the cross-members to the float is taut.
When the mixer-aerator is in the floating position, their stabilizing function does not exist and this situation continues as the immersion progresses until the joining chain is taut. Any displacement of the ballast in the fillable float, for example because the liquid filling the fillable float is displaced by a wave or by the effect of the wind, causes a large destabilization of the device, which has to be compensated, in a preferred embodiment of the invention, by placing perforated intermediate partitions in the fillable ballast tank.
In order to prevent the air from being sucked directly through the propeller when the device is immersed and operating as a mixer, it is necessary to arrange additionally a protective plate between the surface of the water and the propeller. This protective plate, mounted above the fillable float, makes the stabilization of the device even more problematical in view of the fact that, whatever the degree of immersion, it displaces the center of gravity of the device even further above the center of flotation of the central float; in other words, the head of the device is thereby made heavier. It is above all during the intermediate phases of the immersion where the floats fixed to the cross-members are still not able to exert any stabilizing action that an arrangement of this kind is a disadvantage, especially as uncontrolled movements of the ballast in the fillable float may further aggravate the situation. Moreover, the protective plate, which is brought into a position where it is to a certain depth completely below the surface of the water in the event of filling, constitutes a serious obstacle with respect to returning the device to the floating position, in view of the fact that all the water which is situated above this plate has to be driven out laterally before the unit can emerge from the water again in order to operate as an aerator.


The present invention relates to a process for separating isomers by simulated moving bed (SMB) adsorption, comprising separating the raw materials comprising isomers by SMB adsorption, said SMB comprising many adsorption beds each of which is equipped with grids, each of the grids being equipped with the feedstock inlet and outlet pipeline of the bed, the feedstock charged into and discharged from SMB at least comprising feedstocks, desorbent, extract, and raffinate, the extract being enriched with the target product, characterized in that the extract is used as a flushing liquid and respectively charged to first or second bed at the upstream of the feedstock charging position and to one of second to fourth beds at the downstream of the extract withdrawing position. Such process is used for separation of C8 aromatic isomers by adsorption, and can improve the capacity of the device while effectively increasing the purity of the target product separated by adsorption.

The adsorption separation is very effective for the separation of isomers having an extremely small boiling point difference, or of different components having different structural features, e.g. for the separation of p-xylene from other C8 aromatic isomers, and of n-alkanes from hydrocarbons having other structures.
The separation process by SMB adsorption achieves countercurrent contact of the liquid and solid phases and increases the separation efficiency. U.S. Pat. No. 2,985,589, U.S. Pat. No. 3,201,491, U.S. Pat. No. 3,626,020, U.S. Pat. No. 3,686,342, U.S. Pat. No. 3,997,620 and U.S. Pat. No. 4,326,092 describe the separation device and process by SMB adsorption, and use thereof for separation of p-xylene and m-xylene. Douglas M. Ruthven summarizes in Chemical Engineering Science (1989, v44(5):1011-1038) the principle, development, test and model study and industrial process of the separation process by continuous countercurrent adsorption.
Typical SMB adsorption separation comprises at least two streams of feedstocks, i.e. feedstock (F) and desorbent (D), and at least two streams of the discharged materials, i.e. extract (B) and raffinate (R), wherein the extract is enriched with the target product. The positions at which each stream of the feedstocks is fed into or discharged from the adsorption column are moved periodically, and the feedstocks along with the flow direction of the feedstocks in the adsorption column are in a sequence of the desorbent (D), extract (E), feedstock (F) and raffinate (R). The circulation of feedstocks in the adsorption column makes up an closed-loop. The device for controlling the charging and discharging of the feedstocks to and from the adsorption column may be a rotary valve, or a series of on-off valves.
During the adsorption separation, many streams of feedstocks share the delivery pipelines to be charged into or discharged from the adsorption column. The pipeline discharged into and discharged from a certain bed position of the adsorption column will pass the raffinate (R), feedstock (F), extract (E) and desorbent (D) in turn. The previous residual materials in the pipeline will pollute the materials passing through the pipeline, thereby rendering adverse effect on the separation by SMB adsorption. In particular, when the separation by SMB adsorption is used to product high purity products, the residual feedstocks in the pipelines will pollute the extract.
U.S. Pat. No. 3,201,491 discloses a process for increasing the purity of the product continuously separated by adsorption. As for the circumstance that the residual raw material pollutes the extract, it discloses "charging a flush stream comprising a fluid separable from said feed stock into the fluid inlet next upstream relative to the feed stream inlet in an amount not substantially exceeding the volume of fluid in the line of flow between the feed inlet into the fluid distribution center and the feed inlet to the contact zone receiving said feed stream" The flushing liquid is a desorbent-rich stream removed from a fixed mass of sorbent downstream from the desorbent inlet, or a sorbate-rich stream withdrawn from the farthermost downstream mass of sorbent comprising the desorption zone
U.S. Pat. No. 5,750,820 discloses a multiple grade flush adsorption separation process, which is a process for separating the target product from a multicomponent feedstream, comprising introducing said feedstream through at least one fluid communication conduit into said apparatus; flushing said apparatus having at least one fluid communication conduit with a sufficient quantity of at least one initial flushing medium drawn from a first source and comprising said at least one desired component in an initial concentration, such that feedstream residue is flushed from said apparatus by said at least one initial medium; flushing said at least one fluid communication conduit with a sufficient quantity of a final flushing medium drawn from a second source and comprising said at least one desired component in a final concentration, such that said final concentration is greater than said initial concentration and such that initial medium residue from said conduit is flushed into said conduit into said apparatus by said final medium; and withdrawing said product from said apparatus, wherein said first source is separate from said second source and at least one of said first source and said second source is separated from said apparatus
U.S. Pat. No. 5,972,224 discloses a process and device for improving the purity of a product in a simulated fluid bed, said device comprising a number of beds (A1 to An) of a solid or adsorbent that are contained in at least one adsorption column, a fluid distributor plate (Pi) between each bed, whereby each distributor plate is divided into a number of sectors (P10, P11, P12), whereby each distributor plate sector (Pi) includes at least one distribution chamber that is pierced with openings and a fluid circulation space in the vicinity of said openings of the chamber, and whereby said chamber is connected to a transfer line that extends between the chamber and a point that is located outside of the column; during a period T of the cycle, an injection and a draw-off of each materials into and from a distribution chamber that belongs to different plates are carried out, with the process being characterized in that, at an appropriate flow rate, a fluid volume is permanently circulated that circulates in the column in a bypass line that connects different chambers of the distributor plates; the flushing liquid has a composition close to the circulating fluid. The object thereof lies in avoiding greater composition difference between the flushing materials introduced from outside and the materials in the adsorption column to cause disturbance to the separation process. However, such solution will also cause a problem, i.e. a stream of the feedstocks not passing through the adsorption chamber, which is equivalent to a stream of channeling in the adsorption bed, and is adverse to the adsorption separation.
U.S. Pat. No. 6,004,518 discloses a high-purity simulated moving bed adsorptive separation apparatus, comprising a series of individual adsorbent chambers adapted for retaining a bed of adsorbent, a series of fluid transfer lines interconnecting the adsorbent chambers and also allowing passage of feedstock and desorbent streams into the apparatus and removal of extract and raffinate streams from the apparatus, a series of valves for controlling the flow of fluids through the fluid transfer lines and between adsorbent chambers, with a separate set of valves being associated with each adsorbent chamber and with said valves being characterized in that two ports of each valve which controls the flow of the feed stream into a specific adsorbent chamber are connected to the fluid transfer line which connects this specific adsorbent chamber with a next upstream adsorbent chamber; whereby fluid discharged from the next upstream adsorbent chamber may flow through the valve and flush the feed stream from the valve and from a conduit leading from this valve to the specific adsorbent chamber. However, each bed of adsorbent is required to be separate, and the circulating fluid entering the next bed from the previous bed needs to pass through the lines and valve.

This patent is subject to a terminal disclaimer.

Process and device for separation by simulated moving bed adsorption

Research Institute of Petroleum Processing, Sinopec


A system includes a processing device and a non-transitory computer-readable medium having instructions stored thereon that are executable by the processing device to cause the system to perform operations. The operations include generating and running a reservoir simulation model. The reservoir and simulation model includes representative natural fracture or secondary porosity attributes for an area of interest for one or more wells. The operations also include generating a synthetic G-function response using results of the reservoir simulation model. Additionally, the operations include calibrating the synthetic G-function response from the reservoir simulation model to a field G-function response generated using results of a field diagnostic fracture injection test by changing natural fracture characteristics of the reservoir simulation model. Further, the operations include formulating a drilling plan, a completion plan, or both for a wellbore in the area of interest using the synthetic G-function response.

In some reservoirs, whether sandstones, carbonates, or shales, natural fractures often contribute significantly to hydrocarbon fluid recovery. Characterizing natural fractures can be useful to understand the reservoirs better so that an optimal field development plan can be developed. Ultra-tight reservoirs have very low permeability and often no well productivity can exist without natural fractures. Because of the complexity and expense to do so, the natural fractures for these types of reservoirs may not be capable of being characterized, which can complicate decisions on well spacing and fracturing operation methods. Moreover, due to lack of tools, it can be difficult to quantify the impact of natural fractures on production, even though natural fractures can be a significant factor in fluid flow during production.

Well operations involving synthetic fracture injection test


One object is to provide a useful aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH4 having a structure of CHA or MOR and carrying Cu.

Nitrogen oxides may be included in various combustion exhaust gases from internal combustion engines such as diesel engines and gas engines and combustion facilities such as waste-incineration plants, boilers, and gas turbines and exhaust gases from industrial facilities. Some known methods for removing nitrogen oxides from combustion exhaust gases use alcohols as a reducing agent (e.g., Patent Literature 1).
However, when an alcohol is contacted with a catalyst made of a zeolite carrying a metal, which is commonly used for a denitration reaction for removing nitrogen oxides, oxidation of the alcohol occurs in addition to the target denitration reaction, and as a result, aldehydes are generated as an intermediate product in addition to CO and CO2.
Aldehydes are harmful to many organisms, and among them, formaldehyde is highly toxic and causes irritation of the respiratory system, eyes, throat, skin and the like.
Catalysts capable of decomposing aldehydes such as formaldehyde are disclosed in Patent Literatures 2 and 3.
The catalyst disclosed in Patent Literature 2 is made of a zeolite selected from ZSM-5, faujasite, or mordenite, wherein the zeolite carries Pt. Use of this catalyst is costly because the carrier carries a noble metal Pt. In addition, the catalyst has to be used in a large amount to achieve sufficient aldehyde decomposition performance.
The catalyst disclosed in Patent Literature 3 is made of a zeolite selected from mordenite, ferrierite, ZSM-5, β-zeolite, Ga-silicate, Ti-silicate, Fe-silicate, or Mn-silicate, wherein the zeolite carries a noble metal selected from Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au. Among them, those including Pd or Ag as a noble metal achieve a relatively high formaldehyde decomposition rate. However, as with the catalyst disclosed in Patent Literature 2, use of a noble metal increases the cost. In addition, a large amount of the catalyst is required to decompose aldehydes.
Further, Patent Literature 4 discloses a catalyst made of TiO2 carrying an oxide of a metal selected from W, Mo, or V.
However, although the catalyst disclosed in Patent Literature 4 achieves high performance in decomposing formaldehyde at around 500° C. (the conversion rate is slightly less than 90%), the catalyst achieves insufficient decomposition performance below 500° C. That is, after various combustion exhaust gases and exhaust gases from industrial facilities are freed of nitrogen oxides using an alcohol as a reducing agent, the exhaust gases commonly have a temperature below 500° C. In such cases, the catalyst disclosed in Patent Literature 4 cannot be used.
By contrast, the catalysts disclosed in Patent Literatures 2 and 3 made of particular zeolites as a carrier achieve high performance in decomposing formaldehyde at a relatively low application temperature up to around 300° C., and can be used for treating aldehydes in exhaust gases described above.
However, these catalysts use expensive noble metals carried by a carrier, and the cost therefor is high.
Patent Literature 1: Japanese Patent Application Publication No. 2013-226543
Patent Literature 2: Japanese Patent Application Publication No. Hei 10-309443
Patent Literature 3: Japanese Patent Application Publication No. 2012-517343
Patent Literature 4: Japanese Patent Application Publication No. 2005-319393

Aldehyde decomposition catalyst, and exhaust gas treatment apparatus and exhaust gas treatment method


A method and apparatus for automated seismic interpretation (ASI), including: obtaining trained models comprising a geologic scenario from a model repository, wherein the trained models comprise executable code; obtaining test data comprising geophysical data for a subsurface region; and performing an inference on the test data with the trained models to generate a feature probability map representative of subsurface features. A method and apparatus for machine learning, including: an ASI model; a training dataset comprising seismic images and a plurality of data portions; a plurality of memory locations, each comprising a replication of the ASI model and a different data portion of the training dataset; a plurality of data augmentation modules, each identified with one of the plurality of memory locations; a training module configured to receive output from the plurality of data augmentation modules; and a model repository configured to receive updated models from the training module.

This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
An important goal of hydrocarbon prospecting is to accurately model subsurface geologic structures. For example, seismic data may be gathered and processed to generate subsurface models that reveal geologic structure. Seismic prospecting is facilitated by acquiring raw seismic data during performance of a seismic survey. During a seismic survey, one or more seismic sources generate seismic energy (e.g., a controlled explosion, or "shot") which is delivered into the earth. Seismic waves are reflected from subsurface structures and are received by a number of seismic sensors or "receivers" (e.g., geophones). The seismic data received by the seismic sensors is processed in an effort to create an accurate mapping (including images of maps, such as 2-D or 3-D images presented on a display) of the subsurface region. The processed data is then examined (e.g., analysis of images from the mapping) with a goal of identifying subsurface structures that may contain hydrocarbons.
Geophysical data (e.g., acquired seismic data, reservoir surveillance data, etc.) may be analyzed to develop subsurface models. For example, one or more inversion procedures may be utilized to analyze the geophysical data and produce models of rock properties and/or fluid properties. Generally, inversion is a procedure that finds a geophysical parameter model (e.g., a velocity model, in which each unit or cell within the model has associated with it a value indicating velocity with which seismic waves would travel through a portion of the subsurface corresponding to that cell), or a collection of models, which, through simulation of some physical response to those parameters, can reproduce to a chosen degree of fidelity a set of measured data. Inversion may be performed, for example, on seismic data to derive a model of the distribution of elastic-wave velocities within the subsurface of the earth. For example, Full Wavefield Inversion (FWI) simulates seismic waves as induced in the field, and attempts to match the measured seismic response. FWI tends to be a very challenging computational problem because the amount of data to be simulated is large (comprising a full three-dimensional seismic acquisition of a subsurface region), and simulated seismic waves are sensitive to not only a large volume of the earth, but to relatively fine-scale variations in properties within that volume. Therefore, naive parameterization of a subsurface model (e.g., by uniform discretization) may require many volume elements (voxels) of uniform elastic velocities to match simulated data to the observed seismic data.
Seismic interpretation seeks to infer geology (e.g., subsurface structures) from geophysical data, preferably and frequently once that data has been inverted or otherwise transformed into a subsurface model (e.g., the impedance, velocity, or physical properties models noted above, which may take the form of an image of the subsurface). For example, structural interpretation generally involves the interpretation of subsurface horizons, geobodies (e.g., salt anomaly), and/or faults from subsurface models (including, e.g., seismic images). Structural interpretation is currently a laborious process that typically takes months of interpreters' time. As such, structural interpretation is one of the key bottlenecks in the interpretation workflow.
Automated seismic interpretation (ASI) can relieve such bottlenecks. For example, ASI may utilize a machine learning (ML) system with training data, such as data representing a broad set of geophysical and geological environments. The ML system may generate trained models based on the training data. The ML system may then apply the trained models to generate a seismic interpretation of a test dataset and/or infer geologic features therefrom. ML approaches heretofore proposed for seismic interpretation have typically focused on analysis tools to improve the selection of and from alternatives (e.g., deterministic seismic attribute analysis), rather than systems to automate the overall interpretation task. Even with state-of-the-art methods, interpretation tasks remain labor intensive, because existing methods lack an end-to-end system. For example, many interpretation tasks are typically performed by the state-of-the-art methods in two stages detection and grouping: detecting small visual units (e.g., pixel level detection of seismic object) and grouping them into larger structures or object instances (fault, salt, facies instances).
An assumption of a ML model is that the training data and the test dataset are from the same statistical distribution. However, many characteristics of seismic training and test datasets may be different due to disparities in seismic acquisition and processing techniques used to produce the images, disparities in noise (e.g., multiples or swell noise), and/or disparities in geological settings. For example, the quality of seismic images can be affected by seismic acquisition factors such as survey types (e.g., ocean-bottom cable, streamer, or nodal acquisition in marine seismic), azimuthal coverage, data frequency spectrum (e.g., broadband data versus narrowband), and/or spatio-temporal sampling rates. The choice of seismic processing methods can also affect the fidelity of geophysical models, creating various inaccuracies in, e.g., velocity models and images. The geological settings can vary considerably from basin to basin (e.g., salt presence leading to enigmatic structures). When the diversity of training data is limited to a single geological basin, a ML model may have difficulty generalizing to another dataset with different geological structures than those portrayed in the training data. Under current systems and methods, given a new application dataset, an interpreter must manually select from a set of variously trained models (e.g., trained with different training data).
Trained models may be refined and/or retrained based on user feedback. However, given the size of typical datasets, it is impractical to collect user feedback at the pixel level. Moreover, user feedback is typically not shared amongst datasets. A ML system may be sequentially trained on multiple datasets to provide a greater diversity of training data. When a ML system is sequentially trained with multiple datasets, the tasks learned through training with each dataset may be independent. The seismic interpreters then manually correct errors from ML model output independently for each training data set.
Retraining ML systems may be time consuming, complex, and often resulting in unexpected or poor results. For example, the initial training of a ML system on a typical seismic dataset may take on the order of weeks to months. Retraining that follows similar steps to the original training can be expected to take a similar amount of time. While the goal of retraining may be to broaden the knowledgebase of the ML system by learning new interpretation tasks, it is possible that new training data may only reinforce certain geologic features at the cost of defocusing other features.
More efficient equipment and techniques to generate subsurface models would be beneficial.

Automated seismic interpretation systems and methods for continual learning and inference of geological features


An E. coli which can produce phenylalanine and which has an optimum phenylalanine production capability at a temperature between 30.degree. C. and 35.degree. C., and a process for preparing L-phenylalanine by use of the novel E. coli. The novel E. coli is designated MWPEC 13-60 (ATCC 67459).

1. Field of the Invention
The present invention relates to a method for production of L-phenylalanine by recombinant Escherichia coli (E. coli). More particularly, the present invention relates to a novel E. coli containing a gene for the production of L-phenylalanine and a process for the production of L-phenylalanine by use of the novel microbe.
2. Description of the Prior Art
L-phenylalanine is a kind of essential amino acid and can be used for the synthetic production of ASPARTAME.RTM., a sweetening agent. There are many known methods for production of L-phenylalanine by use of microbes. For example, Japanese Kokai Nos. 37-6345 and 60-160,890 disclose a method for production of L-phenylalanine by use of Brevibacterium or Corynebacterium sp. which require tyrosine. Japanese Kokai 55-165,797 discloses a similar method by use of E. coli which requires tyrosine and which is resistant against tryptophan analogues. However, such prior art processes are not particularly suited for L-phenylalanine production on an industrial scale. Furthermore, these processes produce low yields of L-phenylalanine.
Accordingly, it is known that a prior process for manufacturing a product is to amplify copy numbers of a gene which codes for a rate-limiting enzyme in a specific process by genetic engineering techniques. However, in many cases over expression of a gene in a cell leads to deletion of the gene in a plasmid or lysis of a cell which causes the cell to die. There are many methods which properly control the expression of the plasmid. For example, an inducer like IPTG (isopropyl thio-galactoside) was used in the lac operator system to control lac operon and alkaline phosphatase gene (refer to Itakma, A. et al, Science, 198, 1056, (1977), Miyanohava, A. et al; Proc. Natl. Acad. Sci. U.S.A., 80, 1 (1983)).
Also, there is a temperatupe shift method which uses the repressor cI 857 of a phage. Normally, under 37.degree. C. the repressor is active and inhibits the operator so that transcription does not occur, but at a temperature higher than 37.degree. C., the repressor becomes inactive and no longer inhibits the operator so that the gene under control of repressor is expressed.

Method for production of L-phenylalanine by recombinant E. coli


Charging is enabled in ad hoc networks, without access to external infrastructure networks. For example, when a communication is initiated by a mobile communication device within an ad hoc network, a small initiation fee is stored securely on the device, typically on a smart card. Transfer of the charging information may then occur more or less automatically and/or when the device reaches a coverage area of the operator network. The invention is also advantageous for charging in cellular and/or wireless networks, as charging can be performed with low administration costs.

A mobile ad hoc network, MANET, is a communication network that is formed in a more or less spontaneous way and comprises an arbitrary number of participating nodes. It typically comprises wireless communication terminals forming a wireless stand-alone network that is not dependent upon any external network infrastructure. Major motivations for using ad hoc networks include ease and speed of deployment, and decreased or non-dependence upon any infrastructure.
An important property of ad hoc networks is that terminals are able to communicate with each other directly, either through a direct communication from terminal to terminal, or from one terminal to another using other terminals. Terminals participating in the network relay information destined to other terminals in the network. A terminal is here defined as any device, or part of a device, that is able to communicate with other devices, or parts of devices. In the same way, a mobile terminal is defined as a terminal that is either completely mobile, or part of another device, for example a vehicle, that is mobile.
By the introduction of future networks, using technologies such as Ipv6, a larger address space will be available that, together with other future network features, will make ad hoc networks easier to configure and administrate, and therefore more and more attractive.
There are many situations where an ad hoc network may be useful. People meeting at a conference might want to exchange information such as files or documents, without the need for any cables and cumbersome configurations. Search and rescue operations may involve the need to quickly set up a communication network in situations where none or very little communication infrastructure is available.
There are also more common civilian applications to ad hoc networks. Ad hoc networks and their capabilities have the potential of establishing communication networks between users in ways that are being done today in cellular and/or wireless networks. In some places and situations ad hoc networks may provide the capabilities and possibilities of extending, complementing, or even replacing cellular and wireless networks. If an event occurs that causes a lot of people to gather in a certain area that normally is sparsely populated, or even unpopulated, a cellular or wireless network might not be existent, or have enough resources to handle the increased and spontaneously newly formed demand. An ad hoc network can in a situation like this automatically be formed between every communication device, thus replacing the need for other network infrastructures.
Wireless mesh networks resemble ad hoc networks and have the same network properties, except that nodes are not moving. Mesh networks can therefore be regarded as static ad hoc networks. In this way mesh networks can be a more permanent form of ad hoc networks, which may be operated by a more permanent source of power, although this is not necessary.
Mesh networks can also be used as a wireless infrastructure, a wireless network where the infrastructure itself is wirelessly connected. This differs from how present cellular and wireless networks normally are organized, where access to the network within a cell or area is wireless, but where each cell is connected in a wired infrastructure.
One example of this is WiMax mesh networks, constructed with WiMax technology, which resemble static ad hoc networks and mesh network with a wireless infrastructure, with the addition of the static areas where mobility is possible. Access to such a network, or any other type described here, can for example be made with or without the aid of an ad hoc network.
Another example are the so called VANETs (Vehicular Ad hoc NETworks) where the mobile nodes may be different vehicles, such as cars, trucks, trains etc, that are interconnected by mobile networks of ad hoc type. These networks are characterized by the primary nodes, i.e. the cars, trucks etc, having a more permanent source of power and often better antenna capacity. Mobile nodes and user terminals such as mobile phones, PDAs, or other information equipments within the network, can then get access to different forms of information and communication services.
Other types of networks will gradually be developed in the years ahead, but the principle will be the same, the coordination of different types of networks in order to maximize the geographical coverage area and at the same time minimize costs of enlargement and maintenance, with constraints on acceptable or demanded quality of service and performance.
The innovation described below can with advantage be used in all these, both present and future, communication networks.
If we consider a situation in a normal urban area where we have a large number of users, we might consider another application of ad hoc networks, i.e. Metropolitan Area ad hoc Network, (MAN). If a sufficient number of users are willing to use their own devices and resources to participate in an ad hoc network, we may envision a scenario where communications such as voice calls, or some other form of data traffic, are taking place within the ad hoc network itself, instead of in the cellular or wireless network, if such a network exists. In situations like these, we should consider one important difference between these two types of networks. In a cellular or wireless network, an operator is responsible for providing and maintaining the infrastructure that enables the communications. However, building and maintaining a cellular and/or wireless network is an expensive business that is financed by users subscribing to the cellular or wireless services and paying a fee. If we on the other hand consider an ad hoc network formed in a spontaneous way by the users and their devices, the "infrastructure" of the ad hoc network is owned, or maintained by the users themselves. It is therefore natural to assume that since users are using their own resources to maintain the network, they may also be allowed to operate within the network without charge. This may be considered as a situation involving a conflict of interest, regarding charging of communication, between network operators and providers on the one hand and individual users on the other hand. This problem is addressed by the present invention as will be discussed in the following.
Examples of charging procedures in ad hoc networks include published US patent application 2005/0220101. In US 2005/0220101 is described a method of performing charging and rewarding processes in ad hoc networks. Here, a network infrastructure plays a vital role in the handling of charging information, making charging difficult in stand-alone networks.

Charging in ad-hoc communication networks


A lithographic printing plate precursor is disclosed which comprises (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon, the coating comprising an oleophilic layer which, upon image-wise exposure to heat or infrared light and subsequent immersion in an aqueous alkaline developer, dissolves in the developer at a higher dissolution rate in exposed areas than in unexposed areas, wherein the oleophilic layer comprises a polymer that is soluble in the developer and an organic dye in a amount sufficient to provide a visible color to the coating, characterized in that said organic dye does not reduce the dissolution rate of the unexposed areas in the developer.

Lithographic printing presses use a so-called printing master such as a printing plate which is mounted on a cylinder of the printing press. The master carries a lithographic image on its surface and a print is obtained by applying ink to said image and then transferring the ink from the master onto a receiver material, which is typically paper. In conventional lithographic printing, ink as well as an aqueous fountain solution (also called dampening liquid) are supplied to the lithographic image which consists of oleophilic (or hydrophobic, i.e. ink-accepting, water-repelling) areas as well as hydrophilic (or oleophobic, i.e. water-accepting, ink-repelling) areas. In so-called driographic printing, the lithographic image consists of ink-accepting and ink-adhesive (ink-repelling) areas and during driographic printing, only ink is supplied to the master.
Printing masters are generally obtained by the so-called computer-to-film method wherein various pre-press steps such as typeface selection, scanning, color separation, screening, trapping, layout and imposition are accomplished digitally and each color selection is transferred to graphic arts film using an image-setter. After processing, the film can be used as a mask for the exposure of an imaging material called plate precursor and after plate processing, a printing plate is obtained which can be used as a master.
A typical printing plate precursor for computer-to-film methods comprise a hydrophilic support and an image-recording layer of a photosensitive polymer layers which include UV-sensitive diazo compounds, dichromate-sensitized hydrophilic colloids and a large variety of synthetic photopolymers. Particularly diazo-sensitized systems are widely used. Upon image-wise exposure, typically by means of a film mask in a UV contact frame, the exposed image areas become insoluble and the unexposed areas remain soluble in an aqueous alkaline developer. The plate is then processed with the developer to remove the diazonium salt or diazo resin in the unexposed areas. So the exposed areas define the image areas (printing areas) of the printing master, and such printing plate precursors are therefore called 'negative-working'. Also positive-working materials, wherein the exposed areas define the non-printing areas, are known, e.g. plates having a novolac/naphtoquinone-diazide coating which dissolves in the developer only at exposed areas.
In addition to the above photosensitive materials, also heat-sensitive printing plate precursors have become very popular. Such thermal materials offer the advantage of daylight-stability and are especially used in the so-called computer-to-plate method wherein the plate precursor is directly exposed, i.e. without the use of a film mask. The material is exposed to heat or to infrared light and the generated heat triggers a (physico-)chemical process, such as ablation, polymerization, insolubilization by cross-linking of a polymer, decomposition, or particle coagulation of a thermoplastic polymer latex.
WO97/39894 and EP-A 823 327 describe positive-working heat-sensitive materials comprising a hydrophilic support and a oleophilic coating provided thereon. The coating comprises a phenolic resin and a dissolution inhibitor, i.e. a compound which reduces the solubility of the phenolic resin in an aqueous alkaline developer. The interaction between the inhibitor and the phenolic resin is disrupted by exposure to heat or infrared light and, as a result, the exposed areas of the coating dissolve faster in the developer than the non-exposed areas and a lithographic image consisting of hydrophilic (exposed) and oleophilic (non-exposed) areas is obtained. In order to provide a larger solubility differentiation between exposed and non-exposed areas, WO 99/21725, EP-A 864 420 and EP-A 950 517 disclose the use of developer resistance means such as polysiloxane compounds which are capable of preventing the aqueous alkaline developer from penetrating into the phenolic resin layer. The increased developer resistance thus obtained can be reduced by exposure to heat or infrared light and upon subsequent immersion in the developer, a positive lithographic image is obtained.
The coating of the known printing plates contain a colorant, also called contrast dye or indicator dye, in order to provide a visible image after image-wise exposure and development. Such colorants remain in the coating at printing areas and are removed, together with the coating, at non-printing areas. Most of such prior art materials are characterized by a low sensitivity and therefore require a high power during exposure.

Positive-working lithographic printing plate precursor

Abstract: By using non-inhibiting dyes, the sensitivity of the precursor upon image-wise exposure is increased.


A process and apparatus for the production of a spiral or coil shaped puffed extrudate. A tube or other peripheral containment vessel is placed at the exit end of an extruder die. A force or resistance is then applied on the extrudate downstream of the glass transition point, thereby causing the extrudate to back up and coil in the containment vessel.

1. Technical Field
The present invention relates to the production of a spiral shaped puff extrudate and, in particular, to confining the extrudate in a tube or like peripheral containment vessel while applying a force or resistance on the extrudate downstream of the extrudate""s glass transition point. The downstream force or resistance causes the otherwise linear extrudate to xe2x80x9cback-upxe2x80x9d into the containment vessel, thus coiling into the spiral or curl shape.
2. Description of Related Art
The production in the prior art of a puffed extruded product, such as snacks produced and marketed under the Cheetos(trademark) brand label, typically involves extruding a corn meal or other dough through a die having a small orifice at extremely high pressure. The dough flashes or puffs as it exits the small orifice, thereby forming a puff extrudate. The typical ingredients for the starting dough may be, for example, corn meal of 41 pounds per cubic foot bulk density and 12 to 13.5% water content by weight. However, the starting dough can be based primarily on wheat flour, rice flour, soy isolate, soy concentrates, any other cereal flours, protein flour, or fortified flour, along with additives that might include lecithin, oil, salt, sugar, vitamin mix, soluble fibers, and insoluble fibers. The mix typically comprises a particle size of 100 to 1200 microns.
The puff extrusion process is illustrated in FIG. 1, which is a schematic cross-section of a die 12 having a small diameter exit orifice 14. In manufacturing a corn-based puffed product, corn meal is added to, typically, a single (i.e., American Extrusion, Wenger, Maddox) or twin (i.e., Wenger, Clextral, Buhler) screw-type extruder such as a model X 25 manufactured by Wenger or BC45 manufactured by Clextral of the United States and France, respectively. Using a Cheetos like example, water is added to the corn meal while in the extruder, which is operated at a screw speed of 100 to 1000 RPM, in order to bring the overall water content of the meal up to 15% to 18%. The meal becomes a viscous melt 10 as it approaches the die 12 and is then forced through a very small opening or orifice 14 in the die 12. The diameter of the orifice 14 typically ranges between 2.0 mm and 12.0 mm for a corn meal formulation at conventional moisture content, throughput rate, and desired extrudate rod diameter or shape. However, the orifice diameter might be substantially smaller or larger for other types of extrudate materials.
While inside this small opening 14, the viscous melt 10 is subjected to high pressure and temperature, such as 600 to 3000 psi and approximately 400xc2x0 F. Consequently, while inside the small orifice 14, the viscous melt 10 exhibits a plastic melt phenomenon wherein the fluidity of the melt 10 increases as it flows through the die 12.
It can be seen that as the extrudate 16 exits the orifice 14, it rapidly expands, cools, and very quickly goes from the plastic melt stage to a glass transition stage, becoming a relatively rigid structure, referred to as a xe2x80x9crodxe2x80x9d shape if cylindrical, puffed extrudate. This rigid rod structure can then be cut into small pieces, further cooked by, for example, flying, and seasoned as required.
Any number of individual dies 12 can be combined on an extruder face in order to maximize the total throughput on any one extruder. For example, when using the twin screw extruder and corn meal formulation described above, a typical throughput for a twin extruder having multiple dies is 2,200 lbs., a relatively high volume production of extrudate per hour, although higher throughput rates can be achieved by both single and twin screw extruders. At this throughput rate, the velocity of the extrudate as it exits the die 12 is typically in the range of 1000 to 4000 feet per minute, but is dependent on the extruder throughput, screw speed, orifice diameter, number of orifices and pressure profile.
As can be seen from FIG. 1, the snack food product produced by such process is necessarily a linear extrusion which, even when cut, results in a linear product. Consumer studies have indicated that a product having a similar texture and flavor presented in a xe2x80x9ccurl,xe2x80x9d xe2x80x9cspiral,xe2x80x9d or xe2x80x9ccoil springxe2x80x9d shape (all of which terms are used synonymously by Applicant herein) would be desirable. An example of such spiral shape of such extrudate is illustrated in FIG. 2, which is a perspective view of one embodiment of a spiral or curl shaped puffed extrudate 20. The embodiment illustrated in FIG. 2 is an extrudate with a relatively tight pitch, short diameter, and cut at approximately four turns or spirals. It should be understood that when referring to a curl, spiral, or coil spring shaped puffed extrudate, however, Applicant intends that the pitch (which can be a left hand or right hand pitch) and diameter of the curl or spiral in addition to the rod (or other shape) diameter and piece length can each vary independently to provide a wide variety of products. Unfortunately, the high volume process described above provides unique challenges in producing such shape 20.
The usual method for imparting a spiral shape in an extrudate, such as with spiral shaped pasta, involves forcing the dough through a spiral shaped die orifice. As can be readily understood, such solution would not work with a puffed product that is in a plastic melt stage inside the die and produced at the velocity described above, since the product would have no memory of the imparted spiral shape upon exiting the die. In fact, it has been found that it is extremely difficult to meaningfully manipulate the melt as it passes through the die in order to induce an extrudate to wind in free space, by, for example, a temperature differential from one side of the die to the other, without substantially reducing the flow rate of the melt through the die.
Another prior art method for imparting twists or curls in the dough involves using an extruder with rotating nozzles. This process, however, is only viable when the extrudate retains a very pliable form. Further, extrusion by way of rotating nozzles typically, again, requires a greatly reduced throughput rate as compared with the relatively high volume production desirable with the prior art linear products.
To further complicate the matter, a larger surface area is required on the extruder face for the same number of individual dies when extruding a curled product versus a linear product, since the space between each die as between a linear product and a curled product must necessarily be increased to allow for the diameter of the spiral. By way of example, an extruder face may under prior art conditions accommodate 28 individual dies running at 80 lbs. per hour per each die, thereby producing a 2,240 lb. per hour throughput for the entire extruder. In order to theoretically produce the curl shaped extrudate 20 shown in FIG. 2, the same extruder face might only accommodate, for example, 4 individual dies. By way of further example, if it is necessary to slow the throughput rate to less than 30 lbs. per hour per die in order to impart some spiral shape on the extrudate by manipulating the melt inside the die, this reduces the total throughput for that extruder to only 120 lbs. per hour. Thus, by converting an extruder to manipulate the melt inside the die and imparting a spiral shape, the extruder maintains only about 5% of the throughput rate as compared to the standard linear production, even though the throughput for each individual die is reduced to about 38% of the previous throughput rate. The problem becomes even more pronounced if the extrudate throughput is reduced to even lower levels.
It can be easily understood that any prior art solution that requires the substantial reduction in the throughput of the extrudate, therefore, is not an acceptable alternative when, for example, twenty extruders must be used to match the throughput of a single extruder when compared with a linear production line. Forcing the extrudate into some spiral shaped former upon exiting the die is also not practical due to the brittle consistency of the extrudate after it drops below its glass transition temperature. Also, such spiral shaped former could become easily clogged, thereby requiring stopping the entire production line.
Consequently, a need exists for developing a method and apparatus that can impart a spiral or curl shape in a puff extrudate while also maintaining an efficient throughput rate of the product through the extruder. Ideally, such invention should be readily adaptable to existing extruders and dies, require little or minimal modification to such equipment, allow for traditional face cutting, and introduce as few collateral processing issues as possible when integrated into the overall production line.
The proposed invention comprises introducing the extrudate as it exits the extruder die into a containment tube or other peripheral containment vessel that is generally axially oriented with the flow path of the extrudate and has a diameter that approximates the intended diameter of each curl. A slight pressure, force, or resistance is then applied on the extrudate downstream of the glass transition point. This resistance causes the extrudate to xe2x80x9cback upxe2x80x9d and, in essence, coil inside the peripheral containment vessel.
The resistance can be accomplished by any number of means. For example, a blocking element can be placed in front of the containment tube, either outside of or integral to the tube. A hole can be drilled in the containment tube and either a pressure applied or a vacuum applied through such hole, either of which need only be of such magnitude to effect a change in the resistance on the extrudate sufficient to begin the coiling process. A blocking flap under spring tension can also be used, or any number of small obstructions or means of applying a force on the extrudate.
Such a device can be easily fitted to the exit of an extruder die at one end and to a circular extruder face at the other end, thereby allowing for a simple and inexpensive retrofit to existing machinery and allowing for face cutting. Changes in the containment vessel and changes in the method of applying resistance can be used to adjust the pitch and diameter of the curl. Economically high throughput rates can be achieved, thus allowing for efficient utilization of existing extruder production lines without requiring additional extruders to maintain line production rates.
The above as well as additional features and advantages of the present invention will become apparent in the following written detailed description.

Apparatus for producing a curly puff extrudate


The present invention relates to a Lactuca sativa L. var. longifolia Lam seed designated as 41-52 RZ, referred to as Nirvanus, which exhibits resistance against downy mildew (Bremia lactucae Regel), currant-lettuce aphid (Nasonovia ribis-nigri), corky root (Sphingomonas suberifaciens) and lettuce mosaic virus (LMV), the representative seed having been deposited with the National Collections of Industrial, Marine and Food Bacteria (NCIMB) in Bucksburn, Aberdeen AB21 9YA, Scotland, UK and assigned NCIMB Acession No. 41326. The present invention also relates to a Lactuca sativa L. var. longifolia Lam plant produced by growing the 41-52 RZ (Nirvanus) seed. The invention further relates to methods for producing the lettuce cultivar, represented by lettuce variety 41-52 RZ.

1. Field of the Invention
The present invention relates to a new lettuce (Lactuca sativa) variety which exhibits resistance against downy mildew (Bremia lactucae Regel), currant-lettuce aphid (Nasonovia ribis-nigri), corky root (Sphingomonas suberifaciens), and lettuce mosaic virus (LMV).
2. Description of Related Art
All cultivated forms of lettuce belong to the highly polymorphic species, Lactuca sativa, which is grown for its edible head and leaves. As a crop, lettuces are grown commercially wherever environmental conditions permit the production of an economically viable yield.
Lactuca sativa is in the Cichoreae tribe of the Asteraceae (Compositae) family. Lettuce is related to chicory, sunflower, aster, dandelion, artichoke and chrysanthemum. Sativa is one of about 300 species in the genus Lactuca.
Lettuce cultivars are susceptible to a number of diseases such as downy mildew, currant-lettuce aphid, corky root and lettuce mosaic virus (LMV). These diseases result in millions of dollars of lost lettuce crop throughout the world every year.
Downy mildew (Bremia lactucae Regel) is highly destructive of lettuce grown at relatively low temperature and high humidity. Downy mildew is caused by a fungus, Bremia lactucae Regel, which can be one of the following strains: NL1, NL2, NL4, NL5, NL6, NL7, NL10, NL12, NL13, NL14, NL15, NL16, B1:17, B1:21 and B1:23 (Van Ettekoven, K. et al., "Identification and denomination of 'new' races of Bremia lactucae," In: Lebeda, A. and Kristkova, E (eds.), Eucarpia Leafy Vegetables, 1999, Palacky University, Olomouc, Czech Republic, pp. 171-175.)
Downy mildew causes pale, angular, yellow areas bounded by veins on the upper leaf surfaces. Sporulation occurs on the opposite surface of the leaves. The lesions eventually turn brown, and they may enlarge and coalesce. These symptoms typically occur first on the lower leaves of the lettuce, but under ideal conditions may move into the upper leaves of the head. When the fungus progresses to this degree, the head cannot be harvested. Less severe damage requires the removal of more leaves than usual, especially when the lettuce reaches its final destination.
Of the various species of aphids that feed on lettuce, the currant-lettuce aphid (Nasonovia ribis-nigri) is the most destructive species because it feeds both on the leaves of the lettuce as well as deep in the heart of the lettuce, making it difficult to control with conventional insecticides. The lettuce aphid feeds by sucking sap from the lettuce leaves. Although direct damage to the lettuce may be limited, its infestation has serious consequences because the presence of aphids makes lettuce unacceptable to consumers. Additionally, the lettuce aphid has a capacity to act as a vector for a number of viruses, such as gooseberry veinbanding virus, cauliflower mosaic virus, cucumber mosaic virus and lettuce mosaic virus.
Corky root (Sphingomonas suberifaciens) is a soilborne bacterium that is prevalent in most coastal lettuce growing areas. Corky root affects both leaf and head lettuce varieties. The disease typically is more severe when soil temperatures are warmer and in fields where lettuce is grown consecutively. High soil nitrate levels also increase disease severity. Early symptoms of corky root are yellow bands on tap and lateral roots of lettuce seedlings. The yellow areas gradually expand, taking on a greenish-brown color and developing cracks and rough areas on the surface of the root. As disease severity increases, the entire tap root may become brown, severely cracked, and nonfunctional; the feeder root system also may be reduced and damaged. At this point, roots are very brittle and easily break off when examined. Corky root also may cause internal discoloration of the root. When the root is severely diseased, aboveground symptoms consist of wilting during warm temperatures, stunting of plants, and general poor and uneven growth.
Lettuce mosaic virus (LMV) mainly infects lettuce seeds, which is the primary way that the virus is introduced to lettuce in the fields, but also can infect numerous crops and weeds, thereby creating reservoirs of the virus. LMV also can be vectored by aphids, which spread the virus within a lettuce field and introduce it into lettuce fields from infected weeds and crops outside the field.
Symptoms of lettuce mosaic virus vary greatly. Leaves of plants that are infected at a young stage are stunted, deformed, and (in some varieties) show a mosaic or mottling pattern. Such plants rarely grow to full size; head lettuce varieties infected early fail to form heads. Plants that are infected later in the growth cycle show a different set of symptoms. These plants may reach full size, but the older outer leaves turn yellow, twisted, and otherwise are deformed. On head lettuce, the wrapper leaves often will curve back away from the head and developing heads may be deformed. In some cases brown, necrotic flecks occur on the wrapper leaves.
There exists a need for an improved harvestable lettuce product which exhibits a combination of resistance against downy mildew (Bremia lactucae Regel), currant-lettuce aphid (Nasonovia ribis-nigri), corky root (Sphingomonas suberifaciens) and lettuce mosaic virus (LMV).


A semiconductor memory which operates at low power supply voltage with lower power consumption without decreasing writes rate is provided. During data read, a virtual ground line VGj provided to correspond to a bit line pair BLj, /BLj of a read target memory cell 11ij is connected to a ground voltage GND through a transistor 31j. As a result, the bit line BLj (or /BLj) corresponding to xe2x80x9cLxe2x80x9d level is connected to the ground voltage GND through an acceleration circuit AC provided in the memory cell 11ij to thereby accelerate read rate. During data write, the virtual ground line VGj corresponding to the write target bit line pair BLj, /BLj is connected to a power supply voltage VDD through a transistor 33j. As a result, a current is prevented from flowing from the bit line BLj (or /BLj) at xe2x80x9cHxe2x80x9d level to the virtual ground line VGj and the write rate is not decreased.

The present invention relates to a semiconductor memory suited for, for example, a mobile terminal which operates by a battery. More specifically, the present invention relates to a semiconductor memory, such as an SRAM (Static Random Access Memory), which realizes high-rate operation at low power supply voltage.
As a technique related to this field, there has been known hitherto one described in the following document:
Shibata and Morimura, xe2x80x9c0.25-xcexcm SRAM Micro-Cell operating at 1V for Mobile Terminalxe2x80x9d, pp. 1-8, Shingakugiho, ICD97-52 (1997-6), Journal of IEICE (Institute of Electronics, Information and Communication Engineers).
An SRAM is widely used as a cache memory for an ASIC (Application Specific IC) or the like which is used in a mobile terminal or the like. Since the mobile terminal or the like employs a battery as a power supply, low power supply voltage and low power consumption are required for the mobile terminal or the like. If power supply voltage is decreased, the operating rates of MOS transistors which constitute the SRAM decrease. In turn, when the threshold voltages of the MOS transistors are decreased to accelerate the respective operating rates, in a standby state, leak current caused by sub-threshold current increases, thereby disadvantageously increasing power consumption.
To solve these disadvantages, there is proposed an MTCMOS (Multi-Threshold CMOS) based on a CMOS (complementary MOS transistor) LSI technique, which can operate at low power supply voltage (e.g., 1V) when being active and which can prevent an increase in power consumption due to leak current in a standby state.
FIGS. 6A and 6B show a conventional SRAM which utilizes the MTCMOS technique described in the above-cited document. FIG. 6A is a schematic block diagram showing the entire SRAM, and FIG. 6B is a circuit diagram showing the configuration of a memory cell and that of a peripheral circuit thereof.
As shown in FIG. 6A, this SRAM includes a memory cell array 10 consisting of high threshold voltage MOS transistors, and a peripheral circuit 20 consisting of low threshold voltage MOS transistors.
The memory cell array 10 is comprised of a plurality of word lines WLi and a plurality of bit line pairs BLj, /BLj (where xe2x80x9c/xe2x80x9d means inversion or low active) arranged to be orthogonal to the respective word lines WLi. Memory cells 11ij for data storage are connected to the intersections between the word lines and the bit line pairs, respectively.
The peripheral circuit 20 includes an address decoder 21 and an input/output circuit 22.
The address decoder 21 is a circuit which decodes a row address in an address signal AD applied from the outside of the SRAM, and selects a corresponding word line WLi in the memory cell array 10. The input/output circuit 22 is a circuit which decodes a column address in the address signal AD to output a column select signal/Yj, and which reads and writes data DA from and to the memory cells 11ij connected to the bit line pair BLj, /BLj selected by this column select signal/Yj in accordance with a read control signal/RE and a write control signal/WE, respectively.
The peripheral circuit 20 is connected to the power supply voltage VDD of a battery through a switch 23 consisting of a high threshold voltage MOS transistor. In a standby state, the switch 23 is controlled to be turned off using a sleep signal SL to thereby suppress the consumption of the battery caused by sub-threshold leak current. On the other hand, the memory cell array 10 is constantly turned on since the memory cell array 10 cannot be disconnected from the power supply during a standby state so as to hold the storage contents of the memory cells. Due to this, the MTCMOS technique is applied to the memory cell array 10 in order to suppress the sub-threshold leak current and to accelerate operation rate.
As shown in FIG. 6B, each memory cell 11ij in this memory cell array 10 includes a flip-flop FF consisting of high threshold voltage inverters L1 and L2 which hold data on nodes N1 and N2. A high threshold voltage N channel MOS transistor Q1 driven by the potential of the word line WLi connects the bit line BLj with positive phase to the node N1. A high threshold voltage N channel MOS transistor Q2 driven by the potential of the same word line WLi connects the bit line /BLj with opposite phase to the node N2.
Further, the memory cell 11ij includes an acceleration circuit AC which encourages discharging the bit line pair BLj, /BLj and thereby accelerates read operation. The acceleration circuit AC consists of low threshold voltage N channel MOS transistors Q3 to Q6. The transistors Q3 and Q4 are connected to the bit lines BLj and /BLj, respectively and driven by the potential of the word line WLi. The transistors Q3 and Q5 are connected in series and the transistors Q4 and Q6 are connected in series. One end of the transistors Q5 and Q6 are connected to each virtual ground line VGj arranged in parallel to the bit lines BLj. The transistors Q5 and Q6 are driven by the potentials of the nodes N1 and N2, respectively.
One end of the virtual ground line VGj is connected to a ground voltage GND through a high threshold voltage N channel MOS transistor 31j. The transistor 31j is controlled to be turned on and off by the output signal of a NOR circuit 32j which NORs the read control signal/RE and the column select signal/Yj.
The operation of the memory cell 11ij shown in FIG. 6B will next be described.
During data write, when the word line WLi is selected to be set at xe2x80x9cHxe2x80x9d level, the transistors Q1 to Q4 are turned on and the data of the bit line data pair BLj, /BLj is held in the flip-flop FF. At this moment, the read control signal/RE is inactive and set at xe2x80x9cHxe2x80x9d level. Therefore, the output signal of the NOR circuit 32j is at xe2x80x9cLxe2x80x9d level and the transistor 31j is turned off. Accordingly, the virtual ground line VGj turns into a floating state and the transistors Q3 and Q4 in the acceleration circuit AC do not influence data write operation.
During data read, when the read control signal/RE is activated to be set at xe2x80x9cLxe2x80x9d level and the column select signal/Yj is selected to be set at xe2x80x9cLxe2x80x9d level, the level of the output signal of the NOR circuit 32j becomes xe2x80x9cHxe2x80x9d level. As a result, the transistor 31j is turned on and the virtual ground line VGj is connected to the ground voltage GND. If the word line WLi is then selected to be set at xe2x80x9cHxe2x80x9d level, the transistors Q1 to Q4 are turned on. At this moment, one of the nodes N1 and N2 is at xe2x80x9cHxe2x80x9d level, so that one of the transistors Q5 and Q6 is turned on.
For example, when the node N1 is at xe2x80x9cHxe2x80x9d level and the node N2 is at xe2x80x9cLxe2x80x9d level, the transistor Q5 is turned off and the transistor Q6 is turned on. As a result, not only the inverters L1 and L2 drive the bit line pair BLj, /BLj but also the low threshold voltage transistors Q3 to Q6 having high current driving abilities drive the bit line pair BLj, /BLj. Thus, read operation can be accelerated. That is, when the xe2x80x9cHxe2x80x9d level of the node N1 and the xe2x80x9cLxe2x80x9d level of the node N2 are to be read, the transistor Q6 is turned on. Due to this, the potential of the bit line /BLj is decreased to the ground voltage GND through the transistors Q4, Q6 and 31j, accelerating the read operation.
Further, in a standby state, the high threshold voltage transistor 31j is turned off by the output signal of the NOR circuit 32j and the leak current caused by the sub-threshold currents of the low threshold voltage transistors Q3 to Q6 is shut off, so that low power consumption can be realized.
The conventional memory cell, however, has the following disadvantages.
During data read, the transistor 31j is turned on, the virtual ground line VGj is connected to the ground voltage GND, charge from the acceleration circuit AC is discharged to the ground voltage GND through this transistor 31j and the read operation is thereby accelerated.
In write operation performed after this read operation, the transistor 31j is turned off and the virtual ground line VGj turns into a floating state. At this moment, the potential of the virtual ground line VGj is close to the ground voltage GND. It is assumed herein, for example, that while the node N1 is at xe2x80x9cHxe2x80x9d level and the node N2 is at xe2x80x9cLxe2x80x9d level, inverted data is written to the nodes N1 and N2 (i.e., xe2x80x9cLxe2x80x9d level is written to the node N1 and xe2x80x9cHxe2x80x9d level is written to the node N2). In this case, when the level of the word line WLi rises to xe2x80x9cHxe2x80x9d level, the low threshold voltage transistors Q3 and Q4 are first turned on as compared with the high threshold voltage transistors Q1 and Q2 and then the transistors Q1 and Q2 are turned on late.
When the transistors Q3 and Q4 are turned on, the transistor Q1 is still turned off to thereby set the node N1 at xe2x80x9cHxe2x80x9d level and the transistor Q6 is, therefore, turned on. Due to this, the potential of the bit line /BLj is decreased to be equal to that of the virtual ground line VGj in a floating state which potential is close to the ground voltage GND, through the transistors Q4 and Q6. As a result, when the transistors Q1 and Q2 are turned on later and the xe2x80x9cHxe2x80x9d level of the bit line /BLj is to be written to the node N2, it is disadvantageously difficult to write the data to the bit line /BLj and the operation rate for writing the inverted data is disadvantageously decreased.
The present invention has been made to solve the disadvantages of the conventional art. It is, therefore, an object of the present invention to provide a semiconductor memory which can prevent write operation rate from being decreasing and which can operate at low power supply voltage with low power consumption.
To attain this object, a first invention of the present invention provides a semiconductor memory comprising: a bit line pair consisting of a first bit line and a second bit line complementary to each other; a pseudo power supply line provided to correspond to the bit line pair; a word line arranged to cross the bit line pair; a data holding circuit provided at an intersection between the bit line pair and the word line, and having a first node and a second node holding data complementary to each other; a high threshold voltage first transistor connected between the first bit line and the first node, and driven by a potential of the word line; a high threshold voltage second transistor connected between the second bit line and the second node, and driven by the potential of the word line; a low threshold voltage third transistor connected between the first bit line and a third node, and driven by the potential of the word line; a low threshold voltage fourth transistor connected between the second bit line and a fourth node, and driven by the potential of the word line; a low threshold voltage fifth transistor connected between the third node and the pseudo power supply line, and driven by the data on the second node; a low threshold voltage sixth transistor connected between the fourth node and the pseudo power supply line, and driven by the data on the first node; a first switch circuit connected between the pseudo power supply line and a ground voltage, and turned on when the data is read from the data holding circuit and turned off otherwise; and a second switch circuit connected between the pseudo power supply line and a power supply voltage, and turned on when the data is written to the data holding circuit and turned off otherwise.