An aircraft structural joint comprising a first structural component provided with an attachment hole that is configured to receive an corresponding attachment fastener provided by a second structural component; a curable composite bush compressed and cured between an outer diameter of the attachment fastener and the attachment hole when the first component is mounted to the second component, wherein the curable composite bush, when cured, prevents radial displacement of the attachment fastener within the attachment hole.

During aircraft structural assembly, it is known to attach two or more components together at a joint by drilling and installing one or more fasteners in predetermined hole positions after the components are mounted at a fixed position relative one another. Once the fasteners are installed the joint is made and a larger structural assembly is formed. It is known that solid bushings or bushes can be used during the assembly of structural joints and assemblies. They are used when unintended eccentricity or gaps exist between a fastener and a corresponding hole into to which the fastener is placed, needs to be removed in order to ensure correct fit of the fastener. Normally a solid bush is machined from a blank or selected from a range of pre-machined solid bushes and then fitted with an interference fit within the existing bore. The solid bush may then be drilled in the desired position to provide a corrected bore into which the bolt is installed.
In the assembly of aircraft structures, machining and drilling of such made to order solid bushing parts to the required accuracy is a precision process and therefore takes time and requires a stop in the assembly, therefore increasing overall costs of the assembly process.
Sometimes the prepared solid bushing or the hole may not correspond to the dimensions of the hole exactly due to hidden irregularities in the surface of the hole itself, which results in a poor seating of the fastener when installed in the hole. Incorrect seating of the fastener in the hole results in the fastener not transferring the applied load fully when the aircraft is in operation, which has static and fatigue implications. Therefore, an aircraft structure may be designed with a conservative assumption that a certain number of fasteners in a structural assembly would be incorrectly seated fasteners. This conservative approach ultimately leads to a design with a higher number of fasteners required to transfer a given load, thus leading to a higher degree of redundancy, however the structural assembly will also be more costly to manufacture, heavier and require more maintenance due to the increased attachment part count. Furthermore, in some cases the hole may be so irregular that redundancy will not suffice for the degree of incorrect seating of the fastener, leading to the hole and the solid bushing needing to be reworked and or even the component to be scrapped. In addition, the use of solid bushings of various sizes requires storage and asset management, which takes up space of the assembly floor and resources. Furthermore, the process of fitting a solid bush into the existing bore may itself result in damage to the assembly, particularly in the case of composites. This again may require rework which can be time consuming and therefore can increase costs.
An object of the invention is therefore to provide a bushing and an aircraft joint incorporating the bushing that is more efficient to build, cheaper to use and less likely to cause damage. A further object is to provide an aircraft structure assembly incorporating one or more joints with bushing in order to decrease assembly time of the structural assembly.
Another object of the invention is to provide a tooling configured to install a bushing according to the object of the invention previously described. Lastly, it is also an object of the present invention to provide a standard sized bushing that is adaptable to fit multiple dimensions of a hole without machining, and furthermore, a standard bushing that is quicker to install and easier to store than those previously known.

Aircraft joint with a curable composite bushing


A method is provided for increasing resolution of an input image in an input bitmap while performing a density preserving smoothing operation. The input bitmap includes a first set of pixels K.times.L.times.b, and the method comprises the following steps: (a) mapping the first set of pixels into a second set of individual pixels .kappa.K.times. .lambda.L.times.b, each of the individual pixels of the second set having a value selected from a set of "b" output states; (b) developing pixel arrays from the second set of individual pixels, the pixel arrays respectively representing local neighborhoods for the individual pixels of the second set, each of the local neighborhoods having a value selected from a set of "c" output states; (c) combining the output state of each individual pixel with the output state of its respective local neighborhood resulting in a selected one of a plurality of decision states, each of the decision states reflecting a current output state of a selected individual pixel and preference of the selected individual pixel for one of the selected b output states, at least one of the decision states having at least one counterpart in the set of decision states; (d) examining the individual pixels within a preselected area to locate a preselected number of individual pixels including a first individual pixel having a selected one of the decision states and at least a second individual pixel having a counterpart value to the selected one of the decision state of the first individual pixel; and (e) altering the respective output states of the first and second individual pixels when each of the first and second individual pixels are within the preselected area wherein the resolution of the output image is changed and the output image is smoothed without altering the density of the output image relative to the input image.

1. Field of the Invention
The present invention relates generally to a technique for converting images in scale or resolution, and more specifically to a technique in which the bit density of a resulting output image is substantially the same as that of the input image.
2. Description of the Prior Art
Image information, be it color or black and white, is commonly generated in a bitmap format at a particular scale, orientation .theta. and resolution K.times.L.times.b, corresponding to a desired printer output, where K is a number of spots per unit of length in one dimension, L is a number of spots per unit length in the other dimension, and b is the depth of each pixel, in number of levels. This bitmap is present for every color separation of the output device, i.e., 4 bitmaps for a 4-color output device, 3 for a 3-color, 2 for a 2-color and 1 for a black and white output device. In a common example of a black and white output, image data comprising a bitmap to be printed is provided to a printer suitable for printing at 300 spots per inch (spi) in both dimensions, at a one bit depth giving 2 levels. Many considerations drive this single selection of resolution, including the desirability of providing only a limited number of fonts (alphanumeric bitmaps) so as to use only a limited amount of storage space. Common software packages available on personal computers or for operation of input scanners for document creation also usually provide only a single resolution output. Images are commonly arranged at a fixed orientation
Increasingly, the resolution available from printers varies over a wider range of choices. Printer resolutions are available over a range, for example, from less than 200 spi to to more than 600 spi. Resolutions vary for a number of reasons, generally related to the quality of the output image. Simply printing a 300 spi bitmap at 400 spi or 600 spi is undesirable however, since the image will be reduced substantially in size on the output page or display. It would be highly desirable to provide the capability of printing any image at any resolution, while selecting the output size and orientation.
It is a common practice to implement conversion of a bitmap of first resolution K.times.L.times.b to a bitmap of second resolution M.times.N.times.d through simple pixel level and raster level operations, such as pixel doubling. When resolution is changed by integer multiples, the resolution conversion can be achieved by pixel replication. Pixel replication, however, does not best use the capabilities of higher resolution output devices. Hence in performing resolution conversion with a higher resolution output device it is desirable to perform a smoothing operation.
Scaling is an identical operation to resolution conversion, i.e., the number of pixels representing the image is increased, except that output image is represented by a lower resolution than the number of increased pixels representing the image. In other words, a conversion is implemented for a bitmap of first resolution K.times.L.times.b to a bitmap of second resolution M.times.N.times.d through simple pixel level and raster level operations, such as pixel doubling, but if the image is then directed to a K.times.L.times.b for output, it is considered scaled.
Alternatively, more elaborate methods than pixel replication have been developed to facilitate resolution conversion, some of which are described in U.S. patent application Ser. No. 07/513,415, filed Apr. 23, 1990, entitled "Bit-Map Image Resolution Converter," and U.S. patent application Ser. No. 07/588,125, filed Sep. 25, 1990, entitled "Bit-Map Image Resolution Converter Compensating for Write-White Xerographic Laser Printing," the pertinent portions of each patent application being incorporated herein by reference. Each of the above-mentioned patent applications contemplates a method of magnifying, by a predetermined magnification factor (n), original image pixels in two dimensions. The method includes the steps of selecting an original image pixel, as well as determining the binary state of both the selected original image pixel and all immediately surrounding original image pixels. Additionally, the selected original image pixel is expanded into an n.times.n array of magnified image pixels to represent the magnification of the selected original image pixel. Finally, a binary state is assigned to each pixel in the array of magnified image pixels according to the pattern of binary signals previously determined for the selected original image pixel and all immediately surrounding original image pixels. In the preferred embodiments of these patent applications, the assignment of the binary states to the pixels in the array of magnified image pixels is made according to a set of state determination rules.
Employing sophisticated resolution conversion techniques does not insure that the resulting output image will have a desirable appearance. For instance, the output image can be excessively blocky and/or contain noticeable "jaggies." Hence, smoothing operations are sometimes used in conjunction with the conversion or scaling of the image. Through use of the state determination rules in the techniques of the above-mentioned applications, smoothing operations are achieved. For example, the method of the patent application entitled "Bit-Map Image Resolution Converter" permits such operations as smoothing of edges, smoothing of half-bitting effects and smoothing of lines. Moreover, the method of the patent application entitled "Bit-Map Image Resolution Converter Compensating for Write-White Xerographic Laser Printing" permits enhancing of single bits in printing and compensating for loss of resolution in write-white printing.
The following patents also disclose techniques for achieving a higher degree of smoothing in the output image:
U.S. Pat. No. 4,280,144, Patentee: Bacon, Issued: Jul. 21, 1981
U.S. Pat. No. 4,437,122, Patentee: Walsh et al., Issued: Mar. 13, 1984
U.S. Pat. No. 4,670,039, Patentee: Neil et al., Issued: Jul. 7, 1987
U.S. Pat. No. 4,847,641, Patentee: Tung, Issued: Jul. 11, 1989.
U.S. Pat. No. 4,280,144 discloses a coarse scan/fine print algorithm. In particular the algorithm is adapted for use in a scheme in which a pixel having two levels of information is transmitted and then reconstructed into a pixel having four levels of information.
U.S. Pat. No. 4,437,122 discloses a technique for enhancing the resolution and quality of characters of a system receiving information initially in the form of image data. Through use of the technique images can be smoothed by appropriately processing unenhanced input pixels. That is, an array of subpixels can be mapped on to a selected unenhanced pixel, and the subpixels of the array can be outputted selectively as black or white to permit smoothing of the resulting output image.
U.S. Pat. No. 4,670,039 discloses a method for smoothing the display of contiguous parallel line segments in a manner to reduce the discontinuities that occur near the ends of the line segments. Smoothing is achieved by adding auxiliary dots of a lesser diameter below the larger main dots forming a first line segment in a given row and adding the same size auxiliary dots above the main dots of an adjacent line segment when the latter are in a row below the given row. The smoothing operation is optimized for multiple cases and line orientations and more than three different dot sizes can be used in the smoothing operation.
U.S. Pat. No. 4,847,641 discloses a technique for enhancing the printing of bit mapped images by piecewise matching of the bitmap with predetermined stored templates or patterns to detect occurrence of preselected bitmap features. Whenever a match occurs, an error signal is generated to produce a corrected or compensated dot or cell to replace a matched bitmap cell. In this manner the printed image of the desired bitmap image is enhanced by substituting in the original bitmap image on a piece-by-piece or cell-by-cell basis, the cells of the preselected feature with error compensated sub-cells.
None of the above references specifically contemplates a technique for resolution conversion or scaling with a smoothing operation in which bit density and corners are preserved. Since altering bit density and/or smoothing corners may be unacceptable in certain resolution conversion or scaling operations, it would be desirable to provide a resolution conversion or scaling method in which smoothing is achieved without affecting the bit density or integrity of the corners.

Method for maintaining bit density while converting images in scale or resolution


An enhanced reading device which secures written material in a fixed location, and moves a video camera across the written text or images for the purpose of automatically registering the video camera at the beginning of each new line. The device uses a manually operated transmission to move the video camera across a line at a speed controlled by the user. The video camera is also stepped to the next line under control of the user. Optional embodiments permit the transmission to be powered and control by push buttons for automatic registration at the beginning of new lines. The device also has a document tray assembly to control vertical movement of the document in relation to the video camera under control of the user. The document tray assembly can also be optionally powered rather than manually operated.

1. Technical Field
The present invention relates to enhanced reading devices for the visually impaired. In particular, it relates to an enhanced reading device which automatically indexes to the next one or more lines and registers the optical reading device at the beginning of the lines.
2. Background of the Invention
A substantial number of individuals suffer from a variety of vision impairments which impairs their ability to conveniently read. One ailment in particular, macular degeneration, afflicts many individuals as they age. Macular degeneration results in the loss of central vision which directly impacts an individual's ability to read, since the reader must rely on peripheral vision. Typically, an individual with macular degeneration uses a magnifying glass to enlarge the written words to so that they can be more easily perceived. However, magnifying glasses have limitations on their ability to enlarge characters. Likewise, moving a magnifying glass across the written line often results in inadvertently moving to the wrong line when the reader steps from line to line. It would be desirable to have a method of enlarging characters beyond the scope of the conventional magnifying glass, and the method of stepping from line to line without losing one's place in the document.
The prior art has attempted to improve upon magnifying glasses through the use of small handheld television cameras which allow an individual to manually scan the camera across the written line. The output of the camera is input to a television screen which can selectively magnify the characters to any desired size which a particular television monitor is capable of displaying. While the use of handheld television cameras allow an individual to display larger characters, thus making it easier to read, handheld cameras may actually make line registration problems even more difficult. This is because the reader follows the camera on its path back to the beginning of the next line. This motion, when watching the television monitor, can result in dizziness and by high fatigue. It would be desirable to have a method of incrementing to a new line without having to carefully control the line registration while moving the camera.

Apparatus and method for an enhanced reading device with automatic line registration


A screw assembly and a spinal implant. The screw assembly includes a screw with a head and a shaft where a screw retention member is positioned beneath the head of the screw and substantially surrounds the shaft of the screw. The screw retention member is formed from a temperature-sensitive material. The screw retention member has a first contracted position adapted for inserting the screw through at least one hole in the spinal implant and a second expanded position adapted for retaining the screw within the at least one hole in the spinal implant. The screw retention member may be in the form of a coiled spring or a collar having a plurality of tabs.

In the simplest terms, the spine is a column made of vertebrae and discs. The vertebrae provide the support and structure of the spine while the spinal discs, located between the vertebrae, act as cushions or "shock absorbers." These discs also contribute to the flexibility and motion of the spinal column. Over time, the discs may become diseased or infected, may develop deformities such as tears or cracks, or may simply lose structural integrity (e.g., the discs may bulge or flatten). Impaired discs can affect the anatomical functions of the vertebrae, due to the resultant lack of proper biomechanical support, and are often associated with chronic back pain.
Several surgical techniques have been developed to address spinal defects, such as disc degeneration and deformity. Spinal fusion has become a recognized surgical procedure for mitigating back pain by restoring biomechanical and anatomical integrity to the spine. Spinal fusion techniques involve the removal, or partial removal, of at least one intervertebral disc and preparation of the disc space for receiving an implant by shaping the exposed vertebral endplates. An implant is then inserted between the opposing endplates.
Spinal fusion procedures can be achieved using a posterior or an anterior approach, for example. Anterior interbody fusion procedures generally have the advantages of reduced operative times and reduced blood loss. Further, anterior procedures do not interfere with the posterior anatomic structure of the lumbar spine. Anterior procedures also minimize scarring within the spinal canal while still achieving improved fusion rates, which is advantageous from a structural and biomechanical perspective. These generally preferred anterior procedures are particularly advantageous in providing improved access to the disc space, and thus correspondingly better endplate preparation.
There are a number of problems, however, with traditional spinal implants including, but not limited to, improper seating of the implant, implant subsidence (defined as sinking or settling) into the softer cancellous bone of the vertebral body, poor biomechanical integrity of the endplates, damaging critical bone structures during or after implantation, and the like. In summary, at least ten, separate challenges can be identified as inherent in traditional anterior spinal fusion devices. Such challenges include: (1) end-plate preparation; (2) implant difficulty; (3) materials of construction; (4) implant expulsion; (5) implant subsidence; (6) insufficient room for bone graft; (7) stress shielding; (8) lack of implant incorporation with vertebral bone; (9) limitations on radiographic visualization; and (10) cost of manufacture and inventory.
Some of the common problems with spinal implants include movement or expulsion of the implant once inserted between adjacent vertebrae. In particular, when the flexible tissue (the annulus) connecting the disks is severed in the surgical procedure additional vertical and lateral instability in the joint is induced. In order to reduce implant movement or expulsion from between the vertebral bodies, spinal implants may be affixed to adjacent vertebrae, for example, using additional fixation elements, such as screws. The use of additional fixation outside of the joint space, for example, by using screws and plates, screws and rods, or screws alone can limit the amount of displacement that occurs as the vertebra move away from one another reducing movement and activity. Unfortunately, screws can loosen, back out, and even break over time.
A number of screw retention or secondary screw fixation devices are available to try to combat the problem of back out. For example, a screw locking plate and fastener assembly may be placed over the heads of the screws or a snap or c-clip may be embedded into the implant body. Typical screw retention devices rigidly fix the screws within the device. This rigidity does not allow for movement of the screws, however, and can result in increased loading in the joint space. In other words, the loading can create pressure points where the screws are located and can produce undesired bone remodeling at those locations. Similarly, implants having aggressive teeth or ridges can remodel the bone around these sharp features providing instability and movement in the joint assembly. Rigid fixation, increased loading and pressure points, and movement and instability of the implant can result in mechanical failure of the screws. Mechanical failure of the screws and associated pieces of the screw retention devices (e.g., screw locking plate, c-clip, etc.) places the patient at risk for unsecured screws and the like in the vertebral disk space. Thus, there remains a need for a screw retention mechanism which secures the screw, but does not create any of the problems mentioned above for traditional screw retention devices.

Self-deploying locking screw retention device


Remote units (113) that require locating are managed by a queue controller (180) such that the number and location of remote units (113) that are transmitting at increased power at any given time is limited. In particular, a queue controller (180) places identification information for remote units (113) requiring location onto queues (203) associated with base stations supplying reference pilots to the remote units (113). Additionally, identification (ID) information for the remote units (113) requiring location is placed onto queues (203) associated with base stations neighboring the base stations supplying the reference pilot to the remote units (113). The queues (203) operate on a first-in-first-out (FIFO) basis, that output remote unit ID at periodic intervals. Once all queues (203) have been emptied of the ID of a particular remote unit (113), location takes place for that remote unit (113).

It is well known that a remote unit's location within a wireless communication system may be determined using a trilateration method. According to such a method, distances between the remote unit and multiple base stations are calculated based on the measurement of a time delay of a signal traveling between the remote unit and each base station. Such a prior-art method for calculating a remote unit's location is described in U.S. Pat. No. 5,508,708 "Method and Apparatus for Location Finding in a CDMA System" by Ghosh et al. and incorporated by reference herein. As described in U.S. Pat. No. 5,508,708, when location of a remote unit is desired, the remote unit may be instructed to increase the power at which it transmits to ensure that a sufficient amount of base stations are able to decode the remote unit's transmission.
Although increasing a remote unit's transmit power will serve to increase the number of base stations that the remote unit is in communication with, during the time that the remote unit is transmitting at increased power levels, other remote units operating in the same geographic area will be negatively affected since the increased transmit power will be generating additional system interference. In a commercial setting, where there can be many remote units requiring simultaneous location estimates, the simultaneous increase in transmit power for all remote units requiring location estimates can cause unacceptably high frame error rates (FERs), resulting in increased dropped call rates as well as reducing the ability of the wireless communication system to determine the location of the remote units. Thus a need exists for a method and apparatus for managing the increased power transmission of a remote unit during location.

Method and apparatus for managing remote unit increased power transmission during location


If the magnitude of a voltage command vector to a motor driver is smaller than a preset value in a control period, in each of a predetermined number of subsequent control periods (a compensation period), a pulse voltage vector is added to the voltage command vector so as to make substantially zero the average value of the added pulse voltage vectors during the compensation periods, and the compensated voltage command vector is used for the subsequent calculation. Also, two direction data for each phase winding are stored at the center of each of the two dead times following the edges of a voltage command pulse in each control period. An estimated phase voltage is calculated from the last voltage command pulse width, a phase voltage fluctuation during the two dead time of each control period and the stored direction data. The rotor position angle is precisely calculated from the estimated phase voltage.

1. Field of the Invention
The present invention relates to a sensorless control system and method of the permanent magnet synchronous motor and, in particular, to a sensorless control system which enables precise control and precise detection of rotor position and speed in a low speed operation of the motor.
2. Description of the Prior Art
The article "A Sensorless Detecting Strategy of Rotor Position and Speed on Permanent Magnet Synchronous Motor" by H. Watanabe et al. appearing in the Electric Society Transactions D, Vol. 110, No. 11, 1990, at pages 1193-1200, discloses an arrangement in which torque control of a permanent magnet synchronous motor (PM motor) driven with AC voltages into which an inverter has converted a DC voltage is achieved without using a sensor for detecting the rotor position angle. Specifically, the position angle and the angular velocity of rotor is obtained through a calculation based on the voltage equation of permanent magnet synchronous motor. A voltage command vector is calculated from the position angle, the angular velocity and a torque command given from the outside, and the inverter applies the AC voltages according to the vector command vector.
A phase winding voltage is necessary to calculate the rotor position angle and angular velocity on the basis of the above mentioned voltage equation, whereas there is a simplified system in which a voltage detecting device is omitted substituting the voltage command vector for it.
In this kind of motor control system, when a pair of series connected switching elements in the inverter is switched, in order to prevent the switching elements from shorting, the switching times of the switching elements are a bit staggered so as to provide a time period when both the switching elements are off (This time period is called a "dead time."). A phase current of the phase in a dead time is detected. The phase voltage of the phase in the dead time is estimated from the detected phase current and used for the calculation of voltage command vector.
However, the smaller the phase current becomes, the larger the estimation error of the phase voltage becomes due to the influence of ripple current etc. Especially if the magnitude of the voltage command vector is small, then the error between the voltage command vector and the actually applied voltage becomes large relatively to the voltage command vector, making it difficult or even impossible to calculate the precise position angle of the rotor.
Japanese Patent Unexamined Publication No. He12-179,277 (1990) discloses a compensation technique of the error voltage caused by the dead time of the inverter. In this technique, an offset current value is added to discretely obtained current values so as to make the current direction the same as the actual current direction. Determining the direction of the current based on the offset current value, a dead time compensation is achieved based on the determined current direction.
However, the above mentioned dead time voltage error compensation technique does not necessary perform precise dead time compensation, makes the system constitution complicated, and requires a expensive device such as an insulation amplifier for voltage measurement.
It is therefore an object of the invention to provide a sensorless control system and method of PM meter which is capable of precisely controlling the torque even if the voltage command vector is small or the motor is operated at a low speed.
It is another object of the invention to provide a sensorless control system and method of PM motor which is capable of precisely calculating the rotor position angle and angular velocity by precisely compensating a voltage error due to a dead time with a simplified arrangement without the need of an expensive device such as an insulation amplifier.

Sensorless control system and method of permanent magnet synchronous motor


A flight control system is provided with one or more modal sensors that are each configured to measure the rate and possibly acceleration for a flexible body mode of the flight vehicle. The modal sensor's rate and suitably acceleration are subtracted from the rate and acceleration measured by the IMU such that the values provided to the flight controller more closely represent only the rate and acceleration of the flight vehicle's rigid airframe component. A piezoelectric modal sensor is capable of sensing a particular flexible body mode over variations in the modal frequency without inducing additional phase loss in the control loop in order to maintain suitable phase and gain margins. Sensors are suitably provided for at least and possibly only the 1st lateral bending modes in the pitch and yaw channels.

1. Field of the Invention
This invention relates to flight control systems that mitigate the effects of flexible body dynamics on flight vehicles such as missiles.
2. Description of the Related Art
Missile flight control systems receive rate and acceleration measurements from an on-board Inertial Measurement Unit (IMU) and apply a flight control law to actuate control surfaces (e.g. fins) to effectuate a guidance command. The missile's airframe flexes as it translates through the air. These flexible body dynamics introduce an unwanted signal to the control loop response. The flight control system must be designed to compensate for these flexible body dynamics or the system could have self-exciting vibrations. In the case where these vibrations are not bounded, catastrophic structural damage and mission failure will occur. In the case where the vibrations remain finite, the additional frequency content in the actuator commands can lead to actuator failure due to overheating and mission failure.
The airframe 10 experiences several different types of flexible body modes under the different loads as it flies through the air including a 1st lateral bending mode 12 and a 2nd lateral bending mode 14 as shown in FIGS. 1a and 1b, respectively, along the pitch and yaw channels, a 1st torsional mode and various fin modes. The 1st lateral bending mode is the most important. In a long cylindrically shaped body such as found in a missile or comparable flight vehicle, the 1st lateral bending mode has the lowest frequency that lies within or within about a decade above the gain cross-over of the controller bandwidth. The specific amplitude and frequency depend on the missile design, the uncertainty in the manufactured components such as the actuators and the changing load conditions. If the flight controller has sufficient bandwidth and minimal latency it may be possible to actuate the control surface to directly compensate the 1st lateral bending mode but this requires a lot of power and places considerable stress on the actuators and flight controller. Other higher frequency modes including the 2nd lateral bending, torsion and fin modes have less effect on the control loop.
In the absence of these flexible body modes the open loop frequency response of a well designed control loop will have the following typical characteristics: 1) high gain at low frequency for good command tracking and disturbance rejection; 2) a slope of between 20 and 40 dB/decade as the gain crosses 0 dB ("gain crossover") for good robustness to time delays; and 3) a slope of at least 20 dB decade above the crossover frequency to attenuate high frequency noise. The difference between the phase and −180° at the gain cross-over is referred to as the "phase margin" and is a measure of the control loop's sensitivity to unmodeled time delays. The difference between the gain and 0 dB at the frequency where the phase passes through −180° (the phase cross-over) is referred to as the "gain margin" and is a measure of the sensitivity of the control loop to gain uncertainties. These margins are normally not independent, as a change in the gain response affects the gain at the phase crossover (gain margin) as well as the frequency at which the gain crossover occurs, which is the frequency used to compute the phase margin. In general, the open-loop phase margin and gain margin should be large to ensure a robust control loop. If the phase-margin is too small then small unmodeled time delays in the real system could result in an unstable control loop. If the gain-margin is too small then small variations in the real system gain could result in an unstable control loop. In missiles and other flight vehicles, the 1st lateral bending mode is typically large enough that the gain of the control loop at the mode frequency, which would otherwise be −20 to −30 dB, is greater than 0 dB, and thus has the potential to become self-excited and destabilize the control loop. Accordingly, the flight control system must be configured to attenuate at least the 1st lateral bending modes and preferably the other higher order modes as well.
One way to compensate for the 1st lateral bending mode is to design the actuator, fins, and IMU placement so that the control loop actively dampens the mode. This is referred to as a phase-compensated control system, in which the actuators are designed to have a higher bandwidth and to actively dampen the 1st lateral bending mode. As a result, the phase is suitably 50-65 degrees (ideally 180 degrees) out-of-phase at the 1st lateral bending mode frequency so that the control loop does not reinforce the mode and cause it to self-excite. This approach can work but is expensive because the actuator mechanisms must be carefully designed and manufactured to dampen and not excite the 1st lateral bending modes and the location of the IMU is critical.
A more common approach is a gain-compensated control system in which digital filters are used to attenuate the flexible body modes. As shown in FIG. 2, a typical flight control system 20 (shown here for the pitch channel) includes a guidance system 22 that provides a guidance command AZC, typically a lateral acceleration command, an IMU 24 including accelerometers and gyros that provide measurements of the acceleration AZM and pitch rate QM, and a flight controller 26 that applies a control law to the guidance command and measured data to issue commands to actuate the control surfaces and effectuate the guidance command. Rate feedback is typically used to augment the stability of the airframe, and acceleration feedback is used to track the guidance command.
The measured rate and acceleration include a desired rigid airframe component that is needed to property control the missile and an unwanted flexible airframe component due to the various flexible body modes. To avoid further exciting the flexible airframe dynamics, a set of digital filters 28 is used to attenuate the unwanted flexible airframe component of the measured rates and accelerations so that the measurements more closely represent only the rigid airframe component. A 1st lateral bending mode digital notch filter (NF) 30 is specially designed for both the yaw and pitch measured rates and accelerations to provide gain-compensation to adequately suppress the effects of the 1st lateral bending modes. Higher frequency mode filters 32 are a suitable combination of low-pass filters (LPFs) and NFs that are designed to attenuate the measured 2nd lateral bending, torsional and fin modes and not introduce significant phase loss or latency.
As shown in FIG. 3a, a typical 1st lateral bending mode digital notch filter 30 has a gain response 50 to attenuate the measured response of the 1st lateral bending mode. A characteristic of causal digital notch filters is that they start to induce phase loss approximately a decade below the notch, and that the wider and deeper the notch the greater the phase loss. The phase response 52 associated with the gain response 50 is shown in FIG. 3b. In this case the digital notch filter introduces significant phase loss, approximately 10°, at frequencies within the flight control bandwidth (in this case <10 Hz). Phase loss is a non-dimensional measure of latency which negatively affects the flight control system's ability to track the input commands. Too much latency can result in an unstable closed loop system. If the notch filter could be designed to be very narrow and only deep enough to attenuate the mode sufficiently, the amount of latency may be acceptable. However, this is impractical due to the inherent uncertainty of the flexible dynamics that results from the variability that occurs during the missile manufacture. Furthermore, the mode frequency and shape change as fuel is consumed, or as the missile stages are dropped. Additionally the amount of attenuation needed varies with flight condition (Mach number and altitude). Often, the digital notch filters are designed to shift with the frequency, and vary with flight condition, but manufacturing uncertainty necessitates wider and deeper notch filters. As digital notch filters are inexpensive to implement and well understood, they are an adequate solution for those applications that can tolerate the bandwidth limitations they place on the flight control system.
As shown in FIGS. 4a-4b and 5a-5b, the magnitude 53 of the frequency response exhibits a gain margin 54 of approximately 3.4 dB and the phase 55 exhibits a phase margin 56 of approximately 16.9°. Furthermore, the gain response at the 1st lateral bending mode frequency peaks up to about −10 dB even with the digital notch filter. In many systems this would be considered either marginally acceptable or unacceptable because both the gain margin and phase margin are lower than would typically be allowed (4 dB and 20° being typical gain and phase margin design goals).
Another approach is to carefully position multiple IMUs about the airframe and process the data to cancel out the effects of the lower frequency flexible body dynamics. This approach has been used in very large expensive rockets whose lower frequency flexible body mode frequencies are within the bandwidth of the flight control system required to stabilize the rocket. These rockets can afford both the cost, additional space, and additional weight associated with multiple IMUs. This approach is not practical for small low cost lightweight missiles whose lower frequency flexible body mode frequencies are at least ½ a decade to a decade above the bandwidth of the flight control system.
Customers are demanding lighter cheaper missiles and higher performance in both speed and maneuverability. These requirements are directly at odds. Lighter cheaper and consequently more compliant airframes experience larger amplitude flexible body dynamics at lower frequencies than a more expensive stiffer airframe, particularly the 1st lateral bending mode which limits the flight control bandwidth and therefore the speed of response. Current solutions are too expensive, bulky and heavy, or cause too much latency so that they fail the maneuverability specification.

Flight control system and method of using piezoelectric modal sensors to mitigate flexible body dynamics


A plasma etching method for etching an etching target layer of a silicon layer through a mask of a silicon oxide film includes the following sequential steps of forming an opening in the silicon oxide film, wherein an opening dimension of a portion between a top and a bottom surface of the mask is enlarged compared to opening dimensions of the top and the bottom surface of the mask and etching the silicon layer by using a halogen containing gas. A gaseous mixture containing HBr gas, NF3 gas and O2 gas is used as the halogen containing gas. A hole or a trench having an opening diameter or an opening width equal to or smaller than 0.2 μm is formed in the etching target layer. Further, a hole or a trench having an aspect ratio equal to or greater than forty is formed in the etching target layer.

Recently, along with the trend for high density and high integration of a semiconductor device, its wiring structure becomes finer rapidly. In forming a fine wiring structure, it is important to form a hole or a trench having a high aspect ratio and a small opening dimension.
Various plasma etching methods have been proposed for forming a hole or a trench in, e.g., a silicon layer (Si layer). As for a plasma etching method, for example, as shown in FIG. 4A, while a silicon oxide film (SiO2 film) 1 having an opening 1A of a predetermined pattern is employed as a hard mask, the silicon layer (Si layer) 2 which is disposed underneath the SiO2 film 1 is etched in accordance with the opening 1A, whereby a hole or a trench 2A is formed as depicted in FIG. 4B. However, reaction products (e.g., SiBrxOy) generated in etching tend to be attached to the opening 1A of a mask, thereby forming deposits 3 as shown in FIG. 4B.
The deposits 3 formed of reaction products in the opening 1A of the mask tend to grow bigger as the hole or the trench becomes deeper to form more deposits 3 in the opening 1A, thereby making the opening 1A narrower as shown in FIG. 4B. As a result, an effective actual opening dimension d′ of the opening 1A becomes smaller and an apparent aspect ratio h/d′ increases. Thus, an etching rate in the hole or the trench 2A becomes low and a very long time is required for etching the hole or the trench of a desired depth. As the hole or the trench 2A gets deeper and the etching rate becomes slower, a sidewall of the hole or the trench 2A tapers away and, occasionally, an etching may be stopped altogether.
Therefore, the applicant of the present invention proposed a technology for preventing reaction products from being attached to the opening of the mask (see, e.g., Reference 1). This technology employs as an etching gas a processing gas containing a gaseous mixture in which one or both of SF6 gas and NF3 gas are added to HBr gas, O2 gas and SiF4 gas, wherein a gas containing C and F is further added to the processing gas. By controlling the timing of adding the gas containing C and F (e.g., CF4 gas) to the etching gas, the accumulation of deposits at the opening of the mask can be suppressed and a hole or a trench having a high aspect ratio can be achieved.
Further, Reference 2 discloses an etching method capable of enhancing an etching anisotropy. In this case, when the semiconductor substrate is etched through a mask which is formed on the semiconductor substrate and has a lid shaped section, etching particles obliquely incident upon the opening of the mask are introduced into the lid, whereby the etching particles can be prevented from being scattered on the sidewall of the trench, thereby realizing an anisotropic etching.
[Reference 1] Japanese Patent Laid-open Application No. 2004-304029
[Reference 2] Japanese Patent Laid-open Application No. H1-216536
However, in the technology disclosed in Reference 1, since the deposits are prevented from being formed in the opening of the hard mask by a gas containing C and F which is added to the processing gas, the gas containing C and F for preventing the deposits is necessary in addition to the main etching gas. Further, since a hard mask itself is reduced by the gas containing C and F, an added amount of the gas containing C and F and a timing of adding it should be controlled. That is, when forming the hole or the trench having a high aspect ratio and an opening dimension equal to or smaller than 0.2 μm, the deposits in the opening of the mask have to be removed or prevented from growing during the etching.
Further, Reference 2 discloses a technology for preventing etching particles from scattering by using a lid of a mask, but it does not mention an attachment of the reaction products or an undesirable effect caused thereby.

Plasma etching method and apparatus, control program for performing the etching method, and storage medium storing the control program


A guard assembly is for an electrical switching apparatus of an electrical system. The electrical system includes a number of conductors each having an insulated portion and an exposed portion that meet at a junction. The electrical switching apparatus includes a housing and a number of terminals connected to the exposed portion of a conductor. The guard assembly comprises: an interconnect member coupled to the housing; and a number of guard members each comprising: a first portion coupled to the interconnect member, and a second portion extending from the first portion away from the housing, the second portion comprising: a first distal end located at the first portion, and a second distal end opposite and distal from the first distal end. Each of the guard members has an opening. The opening receives a conductor. Each junction is located between a second distal end and a terminal.

Field
The disclosed concept pertains generally to electrical systems. The disclosed concept also pertains to electrical switching apparatus, such as circuit breakers, for electrical systems. The disclosed concept further pertains to guard assemblies for electrical switching apparatus.
Background Information
Electrical apparatus, such as electrical switching apparatus, are used to protect electrical circuitry from damage due to a trip condition, such as, for example, an overcurrent condition, an overload condition, an undervoltage condition, a relatively high level short circuit or fault condition, a ground fault or arc fault condition. Circuit breakers, for example, commonly include wiring terminals as a means to attach wires. While the wires are generally insulated, the end that attaches to the circuit breaker wiring terminal has the insulation removed (i.e., stripped).
It is common that the stripped portion of these wires extends to some degree outside the circuit breaker wiring terminal, such that, when a person is exposed to the circuit breaker and associated wiring, the person is also exposed to some portion of the uninsulated wires, and possibly also the uninsulated portion of the circuit breaker wiring terminal. This exposure to uninsulated electrically energized conductors (wires and/or wiring terminals) allows for the possibility of inadvertent contact by a person, tool, or the like, while performing various types of service or maintenance activities. It also allows a condition whereas a person may potentially be exposed to an arc flash hazard.
There is, therefore, room for improvement in electrical systems, and in electrical switching apparatus and guard assemblies therefor.

Electrical switching apparatus with terminal guard assembly


A decoupling capacitor with increased resistance to electrostatic discharge (ESD) is provided on an integrated circuit (IC). The capacitor may be single or multi-fingered. In one example, the capacitor includes first and second electrodes separated by a dielectric material, a source positioned proximate to the first electrode, and a floating drain positioned proximate to the first electrode and separated from the source by the first electrode. A parasitic element, modeled as a bipolar junction transistor (BJT), is formed by current interactions between the source, the floating drain, and a doped area. The floating drain provides a constant potential region at the base of the BJT, which minimizes ESD damage to the IC.

The present disclosure relates generally to forming an integrated circuit device on a substrate and, more particularly, to fabricating a decoupling capacitor as part of an integrated circuit.
Integrated circuit (IC) technology generally needs a relatively stable supply voltage that remains within predefined limits. However, an IC typically includes a large number of switches that may rapidly open and close, and such high speed switching may result in transient currents that cause variations in the supply voltage.
To minimize these variations and maintain proper circuit operation, decoupling capacitors may be used to filter at least some of the noise that may be present between operating supplies (e.g., power (Vdd) and ground (Vss)). The decoupling effect of such a capacitor serves to "smooth out" ripples (e.g., waves or pulses) in the operating voltage. Any ripples in the voltage are passed to ground, while direct current (DC) is passed through to the IC's components. When the capacitor is connected across the IC, a transmission line is created with an impedance of Z=(L/C)1/2, where 'L' is the inductive component and 'C' is the capacitive component. As illustrated by the above equation, increasing the capacitive component (by using a larger capacitor, for example) provides better decoupling.
Decoupling capacitors may be fabricated from large area thin gate oxide capacitors because such capacitors may achieve a relatively high capacitance per unit area. While this type of capacitor may provide decoupling, it also has a number of drawbacks. For example, because thin gate oxide capacitors generally need a relatively large active area, a large die area (e.g., as much as 20-50% of the die area) may be consumed to realize each decoupling capacitor. Furthermore, such large area capacitors are prone to stress failure, thereby limiting yield and/or reliability. For example, if the oxide layer of the capacitor is not thick enough, a stress point may develop and, with time, may cause the capacitor to fail. Alternatively, the capacitor may fail immediately if the oxide layer has a thin hole or other defect. In addition, a large semiconductor resistance may result in a considerable RC time constant, preventing larger capacitors from performing satisfactorily at higher frequencies (e.g., 100 MHz).
In addition to the need for decoupling, electrostatic discharge (ESD) is generally an important issue for ICs. An ESD is generated by a high field potential, which causes 'charge-and-discharge' events (e.g., a rapid flow of electrons between two bodies of unequal charge or between one charged body and ground, with an electronic circuit being the path of least resistance between the two). An ESD may damage an IC by causing leakage currents or functional failures, and may even destroy an IC.
Various ESD simulation models exist, including the Human Body Model (HBM) and the Machine Model (MM). Since the human body has a charge-storage capacitance and a highly conductive sweat layer, the discharge from a person's touch may be simulated with the HBM using a resistor-capacitor (or RC) circuit. A IC device should generally survive an ESD of 2000V or higher with the HBM. The MM uses an ESD simulation test based on a discharge network consisting of a charged capacitor and (nominally) zero ohms of series resistance to approximate the electrostatic discharge from a machine. An IC device should generally survive an ESD of 200V or higher with the Machine Model.
Decoupling capacitors that are used to reduce coupling (e.g., Vdd and Vss power noise) may result in strong current spikes and thus degrade ESD performance. Furthermore, Vdd pad areas on commonly used decoupling capacitors, such as thin oxide capacitors, that occupy a large active area may fail at undesirably low ESD levels. For example, a conventional pad structure without a decoupling capacitor may have tested values of HBM 7.5 KV and MM 350V. However, when the pad structure is associated with a decoupling capacitor, the tested voltages at which an IC fails using the HBM and MM may be reduced to less than the desired ESD voltage levels.
Therefore, what is needed is a decoupling capacitor that combines decoupling with improved ESD resistance.

Taiwan Semiconductor Manufacturing Company, Ltd.


A method for performing ATPG (automatic test pattern generation) and fault simulation in a scan-based integrated circuit, based on a selected clock order in a selected capture operation, in a selected scan-test mode or a selected self-test mode. The method comprises compiling 704 the RTL (register-transfer level) or Gate-Level HDL (hardware description language) code 701 based on the Input Constraints 702 and a Foundry Library 703, into a Sequential Circuit Model 705. The Sequential Circuit Model 705 is then transformed 706 into an equivalent Combinational Circuit Model 707 for performing Forward and/or Backward Clock Analysis 708 to determine the driving and observing clocks for all inputs and outputs of all combinational logic gates in the Combinational Circuit Model 707. The analysis results are used for Uncontrollable/Unobservable Labeling 709 of selected inputs and outputs of the combinational logic gates. Finally, ATPG and/or Fault Simulation 710 are performed according to the Uncontrollable/Unobservable Labeling 709 to generate the HDL Test Benches and ATE Test Programs 711.

In this specification, the term integrated circuit is used to describe a chip or MCM (multi-chip module) embedded with DFT (design-for-test) techniques.
An integrated circuit generally contains multiple clock domains, with each clock domain being driven by a clock, which is either generated internally or supplied externally. Each clock domain further consists of a set of storage elements. Each clock is distributed to the set of storage elements belonging to the same clock domain via a skew-minimized network, which supplies clock pulses to all clock domain storage elements essentially at the same time. While the clock skew within a single clock domain is designed to be negligible, the clock skew between different clock domains can vary greatly for storage elements belonging to different clock domains. Two different types of combinational logic can be distinguished in an integrated circuit containing multiple clock domains. The first is intra-clock-domain combinational logic, which originates and terminates within the same clock domain. The second is inter-clock-domain combinational logic, which originates in one clock domain and terminates in a different clock domain.
Scan-based design is the most widely used design-for-test (DFT) approach for producing high-quality integrated circuits. Scan-based design requires that all storage elements in an integrated circuit, such as D flip-flops, be replaced with their scan-equivalent storage elements, such as Scan D flip-flops, otherwise known as scan cells. These scan cells are connected in such a way as to form one or more scan chains, with each scan chain being controlled by one or more scan enable (SE) signals and one or more clocks, each belonging to a different clock domain.
Testing a scan-based integrated circuit proceeds in a sequence of shift-in/shift-out operations and capture operations, which are repeated for a predetermined number of test patterns. During a shift operation, the scan enable (SE) signals are used to configure the scan cells into scan chains by selecting the scan data input as the input source for all scan cells in the scan-based integrated circuit, and a predetermined stimuli or a pseudorandom stimuli during scan-test and self-test, respectively, is shifted serially through the scan chains to all scan cells in the scan-based integrated circuit. During the capture operation, the scan enable (SE) signals are used to select the data inputs as the input source for all scan cells, to test the functional path of the scan-based integrated circuit using the stimulus loaded during the shift operation.
Automatic test pattern generation (ATPG) in conjunction to fault simulation are used to generate the scan data patterns to test faults in the scan-based integrated circuit, and to measure the fault coverage of the scan data patterns during scan-test. Fault simulation is also used independently to measure the fault coverage of pseudorandom stimuli during self-test. Faults tested include stuck-at faults, transition faults either launched from shift or launched from capture, path-delay faults either launched from shift or launched from capture, IDDQ (IDD quiescent current) faults, and bridging faults. In order to simplify the ATPG and fault simulation process, a cycle-based logic simulator, as opposed to a full timing logic simulator, is embedded within the ATPG and fault simulation engine, which is used to perform the logic simulation of the capture operation during scan-test or self-test. Since the clock skew between different clock domains can vary greatly, it makes it unfeasible to try to apply the clocks of different clock domains simultaneously during the capture operation, since the clock skew between the different clock domains would result in incorrect values being simulated by the cycle-based simulator when compared to results in the actual scan-based integrated circuit. Different approaches for applying the clocks during the capture operation have been developed in order to solve this problem.
Prior-art solution #1, see FIG. 2, is the one-hot approach. In this approach, only one clock is applied during any given capture operation. This clock is used to test the intra-clock-domain combinational logic originating and terminating within the clock domain of the given capture clock, as well as the inter-clock-domain combinational logic terminating in the clock domain of the given capture clock. The advantage of this approach is that by limiting the number of clocks applied during each capture operation to only one clock, the effects of clock skew between the different clock domains cannot negatively affect the results of the cycle-based logic simulator. The disadvantage of this approach is that only a small subset of the combinational logic that exists in a scan-based integrated circuit is tested during a single capture operation, which results in a large number of capture operations, requiring a large number of scan data patterns, being generated to test the complete scan-based integrated circuit.
Prior-art solution #2, see FIG. 3, is the staggered clock approach using multi-cycle simulation. In this approach, all the clocks are applied sequentially during every capture operation. A multi-cycle logic simulator is used to perform the logic simulation of the capture operation in order to be able to perform the ATPG and fault simulation of the staggered clocks. This allows us to test all intra-clock-domain combinational logic and inter-clock-domain combinational logic of the scan-based integrated circuit. The advantage of this approach is that by staggering the clocks and using a multi-cycle logic simulator, the effects of clock skew between the different clock domains cannot negatively affect the results of the multi-cycle logic simulator. A further advantage versus the one-hot approach is that all combinational logic is tested during each capture operation, which reduces the number of scan data patterns generated to test the scan-based integrated circuit. The disadvantage of this approach is that the complexity of the ATPG and fault simulation increases due to the multi-cycle logic simulator. This also increases the amount of time required to generate and fault grade the scan data patterns. Other variations of this approach also exist, where only a limited number of clocks are applied during each capture operation.
Prior-art solution #3, see FIG. 4, is the staggered clock approach using the circuit expansion approach proposed in the U.S. Patent Application 20020184560 by Wang et al. (2002). In this approach, all the clocks are applied sequentially during every capture operation. Circuit expansion is used to create a new circuit model where all clocks are applied simultaneously during the capture operation, while modeling the results of the logic simulation of the original circuit where all clocks are applied sequentially during the capture operation. This allows us to test all intra-clock-domain combinational logic and inter-clock-domain combinational logic of the scan-based integrated circuit. The advantage of this approach is that by performing circuit expansion, a simple ATPG and fault simulation engine can be used to generate and fault grade the scan data patterns while preventing the effects of clock skew between the different clock domains from negatively affect the results of the cycle-based logic simulator. A further advantage versus the one-hot approach is that all combinational logic is tested during each capture operation, which reduces the number of scan data patterns generated to test the scan-based integrated circuit. The disadvantage of this approach is that the circuit expansion results in a larger memory space requirement for the ATPG and fault simulation tool. Furthermore, the depth of the logic cone increases for clocks that are applied later in the capture operation, which increases the time it takes to generate and fault grade the scan data patterns for these clocks. This can also result in some faults becoming untestable due to the amount of backtracks required to search the depth of the expanded logic cones to find a pattern. Other variations of this approach also exist, where only a limited number of clocks are applied during each capture operation.
Prior-art solution #4, see FIG. 5, is the staggered clock approach using the primary capture event approach described in U.S. Pat. No. 6,195,776 by Ruiz et al. (2001). In this approach, all the clocks are applied sequentially during every capture operation. A selected clock is designated as the primary capture event (PCE) and all clocks are applied simultaneously during the capture operation simulation. A cycle-based logic simulator is used to perform a logic simulation with respect to the PCE clock. In order to guarantee that the cycle-based logic simulator can accurately predict the results in the actual scan-based integrated circuit where clocks are applied sequentially, all scan cells are analyzed with respect to the PCE clock to determine whether they can be controlled and observed at the time of the primary capture event. Scan cells that are driven by the PCE clock are labeled as both controllable and observable. Scan cells driven by clocks that are applied before the PCE clock are labeled as uncontrollable, since their value cannot be predicted at the time of the primary capture event. Scan cells driven by clocks that are applied after the PCE clock are labeled as unobservable, since the values captured into these storage elements cannot be correctly determined at the time of the primary capture event.
The advantage of this approach is that by selecting a PCE clock and labeling scan cells as controllable and/or observable with respect to the primary capture event, a simple ATPG and fault simulation engine can be used to generate and fault grade the scan data patterns while preventing the effects of clock skew between the different clock domains from negatively affect the results of the cycle-based logic simulator. A further advantage versus the multi-cycle simulation and circuit expansion approaches is that this approach does not require any additional complexity or memory space. The disadvantage of this approach is that only a subset of the inter-clock-domain combinational logic is tested during any given capture operation, which increases the number of scan data patterns when compared to the multi-cycle simulation and circuit expansion approaches. A further disadvantage is that a larger number of expected unknown ('x') values can be generated, which can create difficulties for existing scan compression solutions. Other variations of this approach also exist, where only a limited number of clocks are applied during each capture operation.
Reference is made to the following:

Method for performing ATPG and fault simulation in a scan-based integrated circuit


An electronic sideline marker for use in football comprises a first display configured to display an indication of a down and a second display configured to display one or more timers. The second display may be configured to display a play clock, a go-clock, and/or a throw-clock. A play clock may first be displayed, and the marker may then receive an indication (e.g., a button press) that the football has been snapped, at which point display of the play clock may be replaced with display of a go-clock. The marker may be configured to output indications when the play clock, go-clock, and/or throw-clock expire. The marker may be configured to electronically communicate with one or more other markers for use in the football game, or one or more other remote electronic devices such as sensors in flag football belts, flags, and/or footballs.

Flag football is a type of gridiron football (American football) in which players wear flags that are attached to belts worn around the waist. When a player on the defense grabs and pulls on the flag of an offensive player who is advancing the ball, the flag detaches from the offensive player's belt and play is halted. Flag football may provide a safer alternative to tackle football, because high-impact collisions are not an integral part of the game.
In certain forms of flag football, as in many forms of tackle football, the offensive team may have a limited amount of time in which it is required to snap the ball to avoid being penalized for delay of game; in many forms of tackle football, this rule is enforced via use of a play clock integrated into an electronic scoreboard or another fixed stadium feature.
Additionally, in certain forms of flag football, rules regarding rushing and or downing the quarterback may differ from rules in tackle football. For example, flag football rules may dictate a period of time following the snap of the football during which defensive players are prohibited from rushing the quarterback. Furthermore, flag football rules may dictate a period of time following the snap of the football after which the quarterback may be automatically deemed down if the quarterback has failed to throw the football. These rules may further increase the safety of flag football by requiring fewer dedicated pass-rushing players and pass-blocking players and by making plays in which the quarterback is directly downed by a defensive player less common.


The present disclosure relates to additive compositions and their use for improving the low temperature properties of motor fuels and fuels. The additive compositions include at least one modified alkylphenol-aldehyde resin and at least one filterability additive chosen from:                the terpolymers of C4 to C22 alkyl (meth)acrylate, C20 to C24 alpha-olefin and maleimide N-substituted by a hydrocarbon chain having between 4 and 30 carbon atoms,        the homopolymers of C1 to C40 alkyl (meth)acrylate, preferably the C8 to C24 alkyl polyacrylates,        the ammonium salts of mono- or poly-carboxylic acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon chain, having between 4 and 30 carbon atoms.

Crude oils or crude petroleums and the middle distillates obtained from crude oils of petroleum origin by distillation, such as gas oil, diesel motor fuel or domestic fuel oil, contain, depending on the origin of these crude oils, different quantities of n-alkanes or n-paraffins which at a low temperature, typically below 0° C., crystallize out as lamellar crystals which have a tendency to agglomerate. There is then a deterioration in the flow characteristics of the oils and distillates. Difficulties occur during transport, and/or storage of the oil or fuel. The wax crystals have a tendency to clog and block pipes, fuel lines, pumps and filters, for example in vehicle fuel systems.
In winter or in conditions of use of the oil, petroleum or the distillate at a temperature close to below 0° C., the crystallization phenomena can lead to deposits on the fuel line walls, even to a complete blockage. These problems are well known in the field of motor fuels and liquid hydrocarbon fuels where numerous additives or mixtures of additives have been proposed and are marketed for reducing the size of the wax crystals and/or changing their shape and/or preventing their formation. The smallest possible crystal size is preferred as it minimizes the risks of blockage or clogging the filter.
The usual agents for improving the flow of crude oils and middle distillates are co- and ter-polymers of ethylene and vinyl and/or acrylic ester(s) alone or in a mixture with low molecular weight oil-soluble compounds or polymers which contain one or more ester, amide, imide, ammonium groups substituted by at least one alkyl chain. Apart from improving the flow of the oil and the distillate, another purpose of the additives for improving the flow is to ensure the dispersion of the wax crystals so as to delay or prevent the settling of the wax crystals and therefore the formation of a layer rich in waxes at the bottom of receptacles, vessels or storage tanks. These additives for dispersing waxes are called WASA (acronym for the term wax anti-settling additive).
The alkylphenol-aldehyde resins originating from the condensation of alkylphenol and aldehyde have been known for a long time as agents for improving the flow of mineral oils: see for example EP 311 452 which describes condensation products of at least 80% mol of dialkylphenols and aldehydes having 1 to 30 carbon atoms; EP0857776 which describes the use of alkylphenol-aldehyde resins in which the alkyl groups of the alkylphenol have 4 to 12 carbon atoms and the aldehyde has 1 to 4 carbon atoms and containing no more than 10% mol of alkylphenols having more than one alkyl group, in combination with ethylene/vinyl ester co- or ter-polymers for improving the fluidity of mineral oils; EP1584673 which describes alkylphenol-aldehyde resins of Mn between 1000 and 3000 originating from the condensation of a C1-C4 aldehyde and a mixture of alkylphenols with a majority of monoalkylphenol, the alkyl group having 1 to 20 carbon atoms intended to improve the low temperature flow properties of motor fuel compositions. Modified alkylphenol-aldehyde resins have also been proposed as additives for improving the low temperature flow of mineral oils: EP1767610 describes alkylphenol resins the condensation reaction of which with the aldehydes is carried out in the presence of fatty acids having 2 to 50 carbon atoms, or their derivatives, such as esters. Recently, the applicant company in patent applications with filing numbers FR2010/61193 and PCT/IB2011/055863 has proposed novel modified alkylphenol-aldehyde resins which can be used for improving the low temperature stability of motor fuels and liquid hydrocarbon fuels and more particularly by limiting the settling of waxes contained in the motor fuels and fuels at low temperature.
These modified alkylphenol-aldehyde resins can be obtained by a Mannich reaction of an alkylphenol-aldehyde condensation resin                with at least one aldehyde and/or one ketone having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms;        and at least one hydrocarbon compound having at least one alkylmonoamine or alkylpolyamine group (i.e. having several amine groups) having between 4 and 30 carbon atoms,        the alkylphenol-aldehyde condensation resin can itself be obtained by condensation        of at least one alkylphenol substituted by at least one linear or branched alkyl group having 1 to 30 carbon atoms, preferably a monoalkylphenol,        with at least one aldehyde and/or one ketone having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.
In continuing its work, the applicant company has discovered that a specific combination of such modified alkylphenol-aldehyde resins with at least one specific filterability additive makes it possible to further improve the low temperature properties, in particular the low temperature behaviour of motor fuels and liquid hydrocarbon fuels. The applicant company has, in particular, discovered an additive composition making it possible to reduce the cold filter-plugging point while maintaining the dispersant and/or anti-settling effect of the modified alkylphenol-aldehyde resins described in patent applications FR2010/61193 and PCT/162011/055863.
The purpose of the present invention consists of proposing additive compositions for improving the low temperature behaviour of the motor fuels and liquid hydrocarbon fuels, in particular, the boiling temperature range of which is comprised between 100 and 500° C., even above 500° C. Another purpose of the present invention consists of proposing improved additive compositions for reducing the cold filter-plugging point while limiting the settling of waxes. The present invention also relates to an additive composition capable of being added to motor fuels and liquid hydrocarbon fuels comprising at least one additional filterability additive for reducing the cold filter-plugging point without affecting the effectiveness of the modified alkylphenol-aldehyde resin on the dispersion and/or the settling of waxes.
The present invention relates, in particular, to a composition of motor fuels and liquid hydrocarbon fuels having a low cold filter-plugging point (according to the standard NF EN 116), advantageously less than or equal to −25° C., preferably less than or equal to −27° C., more preferentially less than or equal to −28° C. and even more preferentially less than or equal to −29° C. The present invention also relates to a composition of motor fuels and liquid hydrocarbon fuels having a settling volume according to the ARAL test of less than 10 mL and/or a delta CFPP before/after settling (according to the standard NF EN 116) less than or equal to 1° C. and/or a delta CP before/after settling (according to the standard NF EN 23015) less than or equal to 1° C.
According to the invention this purpose is achieved by an additive composition comprising:                at least one modified alkylphenol-aldehyde resin capable of being obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin                    with at least one aldehyde and/or one ketone having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms;            and at least one hydrocarbon compound having at least one alkylmonoamine or alkylpolyamine group (alkylamine) having between 4 and 30 carbon atoms,                         the alkylphenol-aldehyde condensation resin itself being able to be obtained by condensation                    of at least one alkylphenol substituted by at least one linear or branched alkyl group having 1 to 30 carbon atoms, preferably a monoalkylphenol,            with at least one aldehyde and/or one ketone having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms, and                        at least one filterability additive chosen from:                    the terpolymers of C4 to C22 alkyl (meth)acrylate, C20 to C24 alpha-olefin and maleimide N-substituted by a hydrocarbon chain having between 4 and 30 carbon atoms,            the homopolymers of C1 to C40 alkyl (meth)acrylate, preferably the C8 to C24 alkyl polyacrylates,            the ammonium salts of mono- or poly-carboxylic acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon chain and having between 4 and 30 carbon atoms.
According to a preferred embodiment, the filterability additive is chosen from:                the homopolymers of C1 to C40 alkyl (meth)acrylate, preferably the C8 to C24 alkyl polyacrylates,        the ammonium salts of mono- or poly-carboxylic acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon chain and having between 4 and 30 carbon atoms.
The subject of the invention also relates to an additive composition comprising:                at least the modified alkylphenol-aldehyde resin,        at least one first filterability additive chosen from the homopolymers of C1 to C40 alkyl (meth)acrylate, preferably the C8 to C24 alkyl polyacrylates and,        at least one second filterability additive chosen from:                    the terpolymers of C4 to C22 alkyl (meth)acrylate, C20 to C24 alpha-olefin and maleimide N-substituted by a hydrocarbon chain having between 4 and 30 carbon atoms,            the ammonium salts of mono- or poly-carboxylic acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon chain and having between 4 and 30 carbon atoms.
According to a development, the ammonium salts are ammonium salts of mono- or poly-carboxylic acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon chain and having between 4 and 30 carbon atoms and of fatty amine and/or of ethoxylated fatty amine. According to another development, the modified alkylphenol-aldehyde resin is capable of being obtained from at least one alkylphenol substituted in para position, preferably from p-nonylphenol.
In particular, the modified alkylphenol-aldehyde resin is capable of being obtained from at least one aldehyde and/or one ketone chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, 2-ethyl hexanal, benzaldehyde, acetone, and preferably from at least formaldehyde. According to a variant, the modified alkylphenol-aldehyde resin is capable of being obtained from at least one alkylamine having at least one primary amine group, and advantageously at least one compound of which all their amine groups are primary amines. According to another variant, the modified alkylphenol-aldehyde resin is capable of being obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound having at least one alkylmonoamine or alkylpolyamine group.
In particular, the modified alkylphenol-aldehyde resin is capable of being obtained from at least one alkylamine with a fatty chain or from a mixture of alkylamines with a fatty chain and preferably from alkylamine(s) having a number of carbon atoms between 12 and 24, preferably between 12 and 22. According to a variant, the modified alkylphenol-aldehyde resin has a viscosity at 50° C. measured using a dynamic rheometer at a shear rate of 100 s−1 on a solution of said resin diluted with 30% by mass of an aromatic solvent comprised between 1,000 and 10,000 mPa·s, preferably 1,500 and 6,000 mPa·s and advantageously between 2,500 and 5,000 mPa·s.
Another subject of the invention relates to an additive composition comprising in addition at least one additional filterability additive chosen from the copolymers and terpolymers of ethylene and of vinyl ester and/or of acrylic ester (EVA and/or EVP). According to a development, the additional filterability additive is chosen from the copolymers of ethylene and vinyl ester (EVA). Another subject of the invention also relates to the use of an additive composition according to the invention, in a motor fuel or a liquid hydrocarbon fuel comprising, preferably, at least one filterability additive chosen from the copolymers and terpolymers of ethylene and vinyl ester and/or acrylic ester, for improving the low temperature properties, in particular for reducing the cold filter-plugging point (CFPP) measured according to the standard NF EN 116, without affecting the effectiveness of the modified alkylphenol-aldehyde resin on the dispersion and/or the settling of waxes. Another subject of the invention relates to the use of a composition according to the invention, in motor fuels and liquid hydrocarbon fuels, for improving the low temperature properties of motor fuels and liquid hydrocarbon fuels.
In particular, the use of such a composition, for reducing both the cold filter-plugging point and the dispersion of waxes and/or for limiting the settling of waxes in motor fuels and liquid hydrocarbon fuels. According to a variant, the motor fuels and/or fuels have a boiling range from 120 to 500° C., preferably 140 to 400° C. and, advantageously, are chosen from jet fuels, gas oils, diesel fuels, domestic fuel oil and heavy fuel oil.
Finally, the present invention relates to a composition of motor fuels or liquid hydrocarbon fuels the boiling temperature range of which is mainly comprised between 100 and 500° C. comprising:                a major proportion of hydrocarbon compounds and/or of vegetable and/or animal oils and/or their oil esters and/or of biodiesels of animal and/or vegetable origin, and        a minor proportion, preferably comprised between 5 and 5,000 ppm by mass, of at least one composition according to the invention.

Additive compositions and use thereof for improving the cold properties of fuels and combustibles

Abstract: The present disclosure also relates to compositions of motor fuels or liquid hydrocarbon fuels including such compositions.


A plasticizing and injecting device for a plastics injection molding machine includes an axially fixed and rotationally driven plasticizing screw, and an injection plunger movable forwards and backwards inside the plasticizing screw by a linear drive and including, at its front end, a non-return valve. An injection cylinder is provided anteriorly of the plasticizing cylinder. The non-return valve can be moved by the injection cylinder forwards and backwards inside the injection cylinder between a rear position at the beginning of the injection process and a front position after completion of the injection process. In addition, a melt chamber is formed between the front end of the plasticizing screw and the non-return valve, and forms, during the injection process and during the holding pressure phase, an annular gap between the injection plunger and the injection cylinder for receiving plastic melt as the plasticizing screw continues to rotate during injection.

The invention relates to a plasticizing and injection device for a plastics processing machine.
Injection molding machines are known having a so-called reciprocating screw for jointly execute the function plasticizing and injection. The screw is caused to rotate in order to melt and transport the plastic. Furthermore, the screw is movable axially for injecting the plastic melt into a mold and has a non-return valve at its leading end. Such a plasticizing and injection device is characterized by its simplicity and its versatility with respect to different applications. A drawback of such a plasticizing and injection device is foremost the adverse effect on the homogeneity of the melt as a result of the rearward movement of the screw during plasticizing because of the absence of a constant screw length for plasticizing and homogenizing the plastic pellets within a cycle. Moreover, the screw is idle during injection and holding pressure phase, thereby adversely affecting the cycle time. Further disadvantageous is the balance that must be struck between plasticizing capacity, on one hand, and injection pressure, on the other hand, for dimensioning of the screw.
To address the afore-mentioned drawbacks, proposals have been made for so-called injection molding compounders to provide a continuously operating twin-screw extruder and downstream thereof one or more injection plunger and cylinder units (DE 19828770 A1, WO 86/06321 A1).
German publication DE 1105153 further discloses an injection molding machine which also provides a functional split between plasticizing, on one hand, and injection, on the other hand. This document discloses a plasticizing and injection device having a plasticizing cylinder which accommodates a rotatable plasticizing screw, a melt chamber anteriorly of the plasticizing screw for receiving and temporary storage of plastic melt, and an injection cylinder downstream of the melt chamber. The injection cylinder can be moved through displacement of the entire clamping unit against the injection cylinder and then moved as unit against a stationary injection plunger to transfer plastic melt into the closed injection mold. The melt chamber is defined on the opposite side of the injection plunger by a recess in the injection plunger, on one hand, and by an extension piece on the plasticizing cylinder, on the other hand. The plasticizing cylinder can be moved back and forth in relation to the stationary injection plunger by means of plunger and cylinder units in order to be able to fill the melt chamber, on one hand, and to displace plastic melt from the melt chamber into the injection cylinder, on the other hand. A channel extends in the stationary injection plunger for connecting the melt chamber with the injection cylinder and is blocked by a ball check valve during injection to prevent backflow of melt. A drawback is, on one hand, the comparably great diameter of the injection plunger, which adversely affects a precise metering of the shot volume. Heating of the melt chamber and injection cylinder has also being shown relatively difficult because the chambers, bounded by the stationary injection plunger, are temporarily exposed and temporarily plunge into a housing. Also the overall construction appears complex and cumbersome as the entire clamping unit has to be moved for operating the injection cylinder.
DE 4401026 discloses a further plasticizing and injection device to provide a functional split between plasticizing, on one hand, and injection, on the other hand. This device includes a plasticizing cylinder with a rotating plasticizing screw and an injection plunger axially movable in the plasticizing screw. The injection plunger is realized in the form of a piston rod with a non-return valve. Provided inside the plasticizing screw is an accumulator chamber for plastic melt which chamber is subdivided by the non-return valve into two separate accumulator chambers of a volume which is dependent on the position of the non-return valve. Both accumulator chambers communicate with the plasticizing space via melt channels in the plasticizing screw. Plastic melt flows via these channels during the plasticizing process to the front and/or rear accumulator chamber in dependence on the position of the injection plunger. After both accumulator chambers have been filled, the injection plunger moves backwards and plastic melt is displaced from the rear accumulator chamber through the open non-return valve to the front accumulator chamber. The injection plunger is moved forwards to inject into an injection mold, without interrupting the rotation of the plasticizing screw. A drawback is hereby the required high energy consumption for heating the accumulator chamber inside the plasticizing screw since heat has to penetrate through the entire thickness of the plasticizing screw. Moreover, an uncontrolled backflow of plastic melt through the melt channels into the screw flights during the injection process. As a result, it becomes difficult to precisely and reproducibly realize the shot volume. Furthermore, problems may be encountered when closing the non-return valve because, as a result of the backflow of plastic melt into the screw flights, the pressure buildup may be inadequate upstream of the non-return valve to enable a complete closing of the non-return valve.
GB-A-1015092 discloses a plasticizing and injection device which also describes a functional split between plasticizing, on one hand, and injection, on the other hand. A rotatable plasticizing screw is arranged in a plasticizing cylinder in an axially immovable manner and an injection cylinder is provided upstream of the plasticizing cylinder. An injection plunger made of two separate parts is situated inside the plasticizing screw, with the rear part extending out of the screw and movable linearly in injection direction by a single-action piston and cylinder assembly. The front part projects forwardly beyond the screw and includes a headpiece with channels in which ball check vales are disposed. Both parts impact one another inside the screw. At metering, plastic melt is advanced forwardly through a very narrow gap between the injection plunger and the injection cylinder and through channels extending in the head of the injection plunger to the space anteriorly of the injection plunger. As pressure builds up, the forward part of the injection plunger is moved backwards and thus also the abutting rear part of the injection plunger. As soon as the required amount of plastic melt is realized and the injection plunger assumes its initial position for the injection process, the rotary drive of the screw is switch off and melt production is stopped. This is necessary insofar as no melt chamber is available which could accept and temporarily store plastic melt during the injection process and possibly also during the holding pressure phase. If the plasticizing screw were to continue to operate, significant pressure would buildup behind the ball check valves and generate a force upon the injection plunger in opposition to the injection direction. This known plasticizing and injection device is thus hardly suitable for short cycle times. In addition, there is a significant risk of unwanted heating of the plastic melt in the very narrow gap between injection plunger and injection cylinder, possibly causing decomposition. As the injection plunger can be operated only in injection direction, there is no option to effect a momentary pressure relief in the melt immediately before injection through a slight backward stroke, a fact that is oftentimes considered beneficial.
German publication DE 1084474 discloses a plasticizing and injection device of a type involved here for a plastics processing machine, having a rotatable plasticizing screw, disposed axially immovable in a plasticizing cylinder, and an injection plunger, arranged in the plasticizing screw and axially movable back and forth by means of a linear drive, with the injection plunger having a non-return valve and with an injection cylinder being provided upstream of the plasticizing cylinder. The plasticizing screw does not completely fill the plasticizing cylinder; rather the forward end of the plasticizing screw is situated offset to the rear in relation to the forward end of the plasticizing cylinder in order to form an antechamber for accepting and temporarily store plastic melt. This antechamber is sized large enough to accept at a distance to its walls the entire injection plunger, which has a diameter greater than the piston rod and is provided with the non-return valve, in the initial position for executing the injection process. As the injection plunger moves out of the injection cylinder during each injection process, implementation of a precise metering becomes difficult. Moreover, the transition from the antechamber to the injection cylinder can easily be damaged when the injection plunger slightly deviates from the injection axis for example. In addition, there are limitations as far as selection of useable non-return valves is concerned because the locking ring may not move out of the injection cylinder.


There are provided an information storage medium capable of real-time recording/playback of digital moving picture information, and a digital information recording/playback system using this medium. In a medium that records/plays back data including video data and control information, the control information (DA21 in FIG. 4; RTR_VMG in FIG. 30) includes information (VOBU entry in FIG. 31) for accessing a specific portion (VOBU) of the video data.

The present invention relates to an information storage medium represented by a large-capacity optical disc and a digital information recording/playback system using the medium.
In particular, the present invention relates to a DVD (digital versatile disc) recording/playback system that considers real-time recording of a moving picture.
The present invention also relates to a recording/playback system which can guarantee continuous playback (or continuous recording) upon continuously playing back (or continuously recording) information using playback devices (disc drives) having various access performances.
Furthermore, the present invention relates to a recording/playback system which can prevent any playback timing errors of video information and audio information recorded on the medium.

This patent is subject to a terminal disclaimer.

Information storage medium and information recording/playback system