An error correcting code and apparatus are used in conjunction with a main memory in which a data word is stored in a plurality of circuits each of which produces multiple outputs. A minimum number of check bits are stored together with the data word for detecting and correcting single bit errors and detecting the existence of multi-bit errors. A parity bit for the entire data word is also stored. For a 32-bit data word, at least 3 bits of the data word are stored in each of 10 memory circuits. Seven check bits and one parity bit are also stored in the 10 memory circuits wherein no more than one of the check bits or parity bit is stored in any one memory circuit. Upon reading the data word from the memory a set of verify check bits and a verify parity bit are generated and compared to the stored check bits and stored parity bit to produce a check bit syndrome and a parity bit syndrome. The check bit syndrome is decoded to produce an output that is input to an error generator circuit together with a parity syndrome for producing error signals indicating occurrence of a single bit error, a multi-bit error, a triple bit error, or a check bit error.

Computer memories typically utilize dynamic random access memories (DRAMs) for the storage of data that is used in the CPU of the computer. This data is subject to corruption due to many possible causes. As a result, memory systems have been refined and developed so that the occurrence of random errors is relatively infrequent. But, in many applications the integrity of the data is so critical that even relatively infrequent errors cannot be tolerated. Various error correction and detection codes have been developed to detect, and in certain situations, correct such errors. The most well known is the Hamming Code, which typically provides detection for one or two-bit errors and correction of one-bit errors. Commercial circuits are available which can implement such a Hamming code in computer memory systems. The technology of the Hamming Code is well known and is widely described in the literature in this field of technology.
The use of the Hamming code is quite effective in conventional memory systems in which one bit of data is stored in each memory device. Large memory systems typically include hundreds, or even thousands of individual memory devices, each of which may contain, for example, 1 megabit, 4 megabits or 16 megabits of data. DRAM devices have conventionally had a one-bit output per device such that a data word is distributed across the same number of memory devices as the number of bits in the word. Randomly occurring errors, generally referred to as soft errors, are most frequently one-bit errors. Further, if a particular memory device were to fail, either permanently or transiently, there would still be produced a one-bit error in the resulting data word. Therefore, by use of a Hamming Code a one-bit error can be detected and corrected. It has been assumed that the probability of multi-bit errors under these circumstances is remote. A Hamming Code can typically detect, but not correct, a two-bit error. However, it is very difficult to economically detect and correct a greater number of bit errors. It has heretofore been the accepted position that the probability of occurrence of multi-bit errors is so remote that it could be safely ignored.
With the introduction of much larger main memory capacities, such as several hundred megabytes for a single computer main memory, it has become necessary to utilize memory circuits which output multiple bits from each device, rather than only a single bit. Typical DRAM memory devices of this type can provide a four-bit output in parallel for memory device sizes such as one and four megabits. It is anticipated that such practice will continue, and possibly have even greater multi-bit outputs when memory circuits go up in capacity to 16 and 64 megabits. But, when a single memory device produces four bits in a single data word, there is a much greater likelihood of having a multi-bit error should there be a failure of that particular memory device.
Certain applications of computer systems have been developed which require an extremely high level of data integrity. The existence of undetected errors, even at the rate of only one or two per year, for such a computer system could result in serious consequences. In view of the greater likelihood of encountering multi-bit errors due to the use of multi-bit output memory devices and the increased criticality of data integrity, there exists a need for a method and apparatus to detect the occurrence of multi-bit errors for data which is stored in such a computer memory.

Error detecting method and apparatus for computer memory having multi-bit output memory circuits


A method for treating shoulder subluxation using an implantable device to stimulate the axillary nerve which in turn activates sensory fibers to relieve shoulder pain and activates deltoid muscle to treat disuse atrophy and possibly augment any weakened voluntary movements. Known stimulation devices are either (1) external requiring surface electrodes or (2) implantable located directly into the deltoid muscle allowing stimulation of the proximate motor-points; each requiring relatively large stimulus currents and neither directly dealing with the pain resulting from the shoulder subluxation. In the present invention, a device is implanted via injection or open surgery proximate to the axillary nerve. Advantageously, the nerve branches into portions that stimulate the deltoid muscle and pass sensory signals. By stimulating the axillary nerve (1) a lower stimulus signal level can be used and (2) pain may be blocked while treating the atrophied deltoid muscle and augmenting weakened voluntary movements.

Loss of upper motor control due to stroke results primarily in limb paralysis and secondarily in disuse atrophy of the affected muscle and shoulder joint. This atrophy may result in complications such as joint pain and skin breakdown, which may be even more troubling to the patient than the loss of motor function. Shoulder subluxation has been observed in 17% to 81% of hemiplegic patients. Muscle paresis around the shoulder joint decreases its stability and results in shoulder subluxation which is among the most commonly cited causes of shoulder pain in hemiplegia. It is difficult to treat these conditions even when traditional rehabilitation techniques and medicines are tried. Currently stimulating signals delivered via surface electrodes have been tried but are of limited use since they are not sufficiently close to the affected muscle to provide sufficient stimulation intensities for the necessary period of treatment. The use of multiple implanted devices is also known for directly stimulating multiple portions of the deltoid muscle. It is believed that such devices also require relatively high amplitude stimulation signals since they must directly stimulate muscle fibers and that they do not directly deal with the pain, until if and when the treatment is actually effective, which could be some period of time.

Electrical treatment to treat shoulder subluxation

Alfred E. Mann Foundation for Scientific Research


Magnetic copper-nickel-tin-manganese alloys are disclosed. Also disclosed are processing steps that can be performed for maintaining and/or changing various magnetic or mechanical properties of the alloys. Further described herein are methods for using such an alloy, including various articles produced therefrom.

The present disclosure relates to magnetic copper-based alloys, in particular copper-nickel-tin-manganese alloys. Also disclosed are various processes for obtaining and/or using such magnetic alloys, including various articles produced therefrom.
Copper-nickel-tin alloys, such as ToughMet® alloys offered by Applicant, Materion Corporation, combine a low coefficient of friction with excellent wear resistance. They are spinodally hardened alloys engineered for high strength and hardness, and resist galling, stress relaxation, corrosion, and erosion. They retain their strength at elevated temperatures, and are easily machined into complex components. These alloys are also non-magnetic.
It would be desirable to provide magnetic copper-based alloys that produce some advantages in certain applications.


A telecommunication system includes a processor, interfaces in communication with the public telephone network and a data network, respectively, and a memory. The memory comprises executable instructions that when executed by the processor direct the system to controllably permit access to a teleconference bridge in response to a communication from a mobile-communication device that includes information responsive to a previously communicated license key. Generally, the communication is in the form of a call from the user of the mobile-communication device. Upon receipt of the call, the telecommunication system confirms that the mobile-communication device communicates a pass code that was included in an encrypted form in the license key.

Audio conferences via a switched telephone network are in widespread use. These conferences may be accomplished by use of a multi-line telephone or by a conference bridge having a telephone number that can be called by all conference participants. Typically, the teleconferencing service provider allocates one or more personal identification numbers (PINs) to subscribers and connects each subscriber to their intended conference based on the PIN entered by the subscriber, through equipment known as a teleconferencing bridge. A conference usually includes a host who organizes or leads the conference and a number of guests. The host may often have additional privileges beyond those of the guests, such as, for example, being able to add or remove guests from the conference. The conference host can be distinguished from the guests by having a PIN that is different from the PIN or PINs assigned to the guests.
Many telecommunications carriers and service providers offer conference call services whereby three or more callers may participate in the same call. To establish a conference call, a host typically arranges with a telecommunications carrier or other service provider to reserve a number of connections (i.e., ports) on a teleconference bridge, which combines (bridges) a plurality of telephone calls. The host may interact with an operator of the telecommunications carrier who, in turn, undertakes the necessary steps to reserve the required number of ports on a particular bridge. Alternatively, a host may reserve the requisite number of bridge ports by interacting with an automated system. Once the host has reserved the requisite number of ports on the bridge, each participant (including the host) enters the conference call by directly dialing a telephone number associated with the bridge to be connected to a bridge port. Upon receipt of a call, the bridge authenticates the caller by prompting the caller to enter an identifier in the form of an access code. Only when the caller enters the proper access code for the particular conference call does the bridge connect the caller with others who have already joined the conference call.
To enter the conference call, each participant must know both the telephone number of the bridge as well as the requisite access code. In practice, the host often receives a separate access code from the other participants to afford the host the ability to control various aspects of the call. Before a scheduled conference call, the host must communicate the bridge number and access code to each participant. For a large number of participants, ensuring that each scheduled participant receives the bridge number and participant code can prove cumbersome, particularly for participants at different locations. The problem of notifying all the conference participants of the conference bridge number and access code becomes even more pronounced for conference calls that occur on a frequent basis, such as every week or even every day. To alleviate this difficulty, some carriers allow the host to reserve the same bridge and use the same participant code. However, not all carriers afford every conference call host the ability to reserve the same bridge for every conference call.
To obviate the need to communicate the bridge number to every participant, some telecommunications carriers that provide conference call services will automatically launch a call to each participant at the start of the conference call. This approach works well for participants whose locations and telephone numbers are known in advance of the conference call. Unfortunately, telecommunications carriers that provide this type of conference call service may not know the location of every intended participant at the outset of the conference call. For example, the host and one or more invited participants may be away traveling, yet available to participate from a mobile telephone.
Many mobile telephone handsets provide a platform that supports multiple functions. These multiple functions include the receipt of games, ring tones, applications and multimedia content including music, video, broadcast programming, etc. for operation on the handset. The adaptability of these mobile telephone handsets makes it problematic for a service provider to ensure that application software provided to and executed on a particular mobile telephone handset is used to access an intended device configured to support a service.
Thus, there is a need for improved systems and methods that direct mobile-communication device applications to a desired device to ensure that providers of application software are compensated via subscriber use of a designated service device.

Systems and methods to direct a mobile communication device to a preferred teleconference bridge

American Teleconferencing Services, Ltd.


A conveying system includes: a linear induction motor including a stator provided with a plurality of primary coils arranged along a conveying path and a mover provided movably along the conveying path; one or more first inverters that are provided corresponding to at least one of the primary coils in one or more areas requiring positioning on the conveying path to perform vector control with a sensor; one or more second inverters that are provided corresponding to at least of the primary coils in one or more areas requiring no positioning on the conveying path to perform V/F control; and a controller that is configured to output a speed reference to the first second inverters to control electric supply to the primary coils and to output the speed reference based on a feedback position received from a detector to the first inverter, to perform position control.

Widely known are conveying systems using a linear induction motor as a driving source and including a plurality of primary coils arranged along a conveying path and a secondary conductor provided in a manner facing the primary coils on a moving body movably arranged on the conveying path. Such conveying systems supply electricity to the primary coils, thereby sequentially applying a thrust to the secondary conductor to move the moving body.
Conventionally, there has been developed a conveying system that is provided with inverters for respective primary coils and that controls electric supply to each coil with a control reference received from a central controller. Related conventional technologies include a technique described in Japanese Patent Application Laid-open No. H7-327301.
Conveying systems have a general technological target to convey an object accurately by carrying out positioning with high accuracy. The conventional technology, however, has no description about specific control, specifically, positioning control of the primary coils, thereby failing to carry out highly accurate positioning. As a result, the conventional technology cannot achieve the technological target described above.


Systems and methods are provided through which a template in the spatial domain is generated and combined with an image. Later, the combined image can be decoded to determine the extent of scaling and or shifting or the combined image. The template comprises at least one vertical or horizontal band. The horizontal band(s) determine the extent of scaling and/or shifting along the vertical axis, and the vertical bands determine the extent of scaling and/or shifting along the horizontal axis of the combined image. Using both horizontal and vertical bands enables decoding of shifting and scaling along both axis, and creates a grid. Each band specifies a predetermined characteristic of modifying the luminance of the corresponding pixels of the image. In one alternative, the modification of the image is performed to the extent that the bands are invisible to the naked eye.

With the increasing popularity of computers, and with the advent of mass networks such as the Internet, electronic distribution of content, such as documents, images, and sound, has become much more common. However, electronic content distribution has raised concerns for the creators of such content. For example, content creators wish to ensure that copyright and other authorship and ownership and usage information is attached to their electronic content, such that subsequent attempts to determine the author, owner and user of the content are successful. Furthermore, the creators wish to determine that their content has not been altered since first being distributed electronically.
Watermarking is a technology designed to address the concern of digital content owners and providers who wish to distribute their products and material on the Internet or by other means that their content, which includes text images, and video, may be copied, altered and distributed without permission. Digital watermarking inserts information in digital content that can be recovered even if the watermarked content is altered with significant degradation or alteration.
Watermarking allows questions of ownership and use of a given piece of content—which may be widely distributed by virtue of the Internet, for example—to be resolved, by attempting to decode an embedded secret from the content. That is, by watermarking content data, the data owner can determine whether a suspect piece of content is his or hers by determining whether the watermark is present in the suspect data. Watermarking is a technique used to label digital content by hiding copyright or other information into the underlying data. Unlike encryption used to restrict access to data, watermarking can be employed to provide solid evidence of authorship and usage. Like data hiding generally, the watermark remains with the media through typical content-preserving manipulations, e.g. cropping, compression, and so forth. However, unlike data hiding generally, with watermarking an unauthorized user cannot access the embedded information (e.g. the watermark). In addition, the power of an effective watermarking system lies in its degree of robustness. Robustness ensures that the embedded watermark can not be removed or tampered without destroying or at least degrading the quality of the information.
Generally the information embedded in the watermark is a pattern whose location is known by the watermark detector. Robust watermarks can be detected following operations that do not change the position of the watermark such as the addition of noise and blurring. However, detectors that must know the position of the watermark cannot detect it following operations that change its position. Common operations that change the position of a watermark are shifts and scaling. Images can be scaled and shifted following printing and scanning and videos can be scaled and shifted following analog to digital conversion.
A template is a secondary watermark that can be used to synchronize the detector with the primary watermark. Templates like other watermarks can be embedded in the spatial domain or the frequency domain. A template that is embedded in the frequency domain using the Fourier transform increases the magnitude of Fourier coefficients as disclosed by Shelby Pereira, Joseph J. K. O' Ruanaidh and Thierry Pun, "Secure robust digital watermarking using the lapped orthogonal transform, Society of Photo-optical Instrumentation Engineers, Vol. 3657, January 1999, pp. 21–30, which is incorporated herein. Templates produced by this method tend to become visible for images and video the size used by MPEG1 or smaller. Visibility is a problem for a template because a visible template is more easily detected, and then thwarted. Templates implemented in the frequency domain are difficult to the control artifacts, and are easy to distort through common image processing operations such as blurring and low-bit rate compression.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an invisible watermark that in the spatial domain that can decoded even after scaling and shifting of the image.

This patent is subject to a terminal disclaimer.

Template for watermark decoder synchronization


A golf hat and golf ball marker assembly containing a hat, a metal strip, and a disc-shaped, metallic golf ball marker. The metal strip is affixed to the side of the hat such as by rivets. Positioned on one side of the strip is a depressed well having a magnetized bottom. The diameter of the well is slightly larger than the diameter of the marker so that the marker fits snugly in place in the web with a very little lateral movement. The depth of the well is slightly less than the thickness of the marker so that the marker extends slightly out of the well for each removal. The marker is held in the well when not in use by virtue of magnetic attraction.

It is well known that when a golf ball is hit onto the putting green, a marker is used to temporarily mark the position of the ball so that the ball may be removed to allow another golf ball to be played. When the first golf ball is ready to be putted, the marker is picked up and replaced with the ball. This action occurs frequently throughout a round of golf. The marker must therefore be held in a convenient location which is easily accessible to the golfer and from which the marker will not be lost.
Several articles have been suggested for holding markers. U.S. Pat. No. 4,315,624 disclosed a ground repair tool chain retains a ball marker, and U.S. Pat. Nos. 3,895,797, 4,930,500, and 5,364,094 disclose articles for holding ball markers which can be releasable attached to or held by the golfer's clothing. Because these items are small and not securely attached to anything, they may become misplaced when not is use and require golfers to specifically remember to take them when going to play golf. Also, these articles may need to be worn in places which many golfer's find uncomfortable, such as on a belt or shirt.
U.S. Pat. No. 4,130,950 discloses a marker held to a golf shoe by a permanent magnet. The marker is positioned in a place which for which for many golfers is difficult to reach and from which it may become lost without the golfer realizing it.
U.S. Pat. No. 5,135,220 discloses a marker held to a flexible web worn about a golfer's wrist. This is another article of the type described above which the golfer must specifically remember to bring and which may become lost. Furthermore, the flexible web may be uncomfortable to some golfers and may even interfere with their play.
Thus, there remains a need for an article for holding a golf ball marker which is easily accessible to the golfer and which minimizes the inconvenience to the golfer and the risk of being lost or misplaced. The present invention provides such an article.


An optical imaging system incorporates a beam splitter, which is moveable to a beam-splitting position where the beam splitter intercepts the light on an input optical path and a non-beam-splitting position where the beam splitter is located outside of the input optical path. The beam splitter includes a body penetrated by an aperture and a reflective surface surrounding the aperture. When the beam splitter is located in the beam-splitting position, a portion of the light in the optical path is transmitted through the aperture and a portion of the light in the optical path is reflected from the reflective surface.

Optical imaging systems, such as digital imaging telescopes, can provide different optical paths to direct light for different applications. FIG. 1A schematically illustrates a typical prior art digital imaging telescope 10. Digital imaging telescope 10 has a telescope body 12 which defines a primary optical cavity 13. Primary optical cavity 13 houses an objective lens system 14, an erecting prism system 16 and an eyepiece 18. Eyepiece 18 houses an eyepiece lens system 20 which provides a magnified image to a user's eye. Telescope body 12 also defines an optical cavity 24 which houses a secondary objective lens 22 and a digital imaging system 26. Digital imaging system 26 is typically implemented using charge-coupled-device (CCD) technology or complementary metal-oxide semiconductor (CMOS) technology.
Digital imaging telescope 10 provides two light paths 30, 32. Light on path 30 travels through objective lens 14 into primary optical cavity 13 and is focused at point F1 in front of eyepiece lens system 20. Light on path 30 allows users to view objects through eyepiece 18. Light on path 32 travels through objective lens 22 into secondary optical cavity 24 and is focused at point F2 to provide light to digital imaging system 26. Digital imaging system 26 digitizes images to generate digital image data.
Digital imaging telescope 10 suffers from the drawback that it requires two objective lenses 14, 22, each having relatively low f/#s which tends to be expensive. Also, the characteristics of objective lens 22 (e.g. aperture, focal length and f/#) and the optical path length of light path 32 are different from the characteristics of objective lens 14 and the optical path length of light path 30. Consequently, the images digitized by digital imaging system 26 differ from the images observed by a user through eyepiece 18. Furthermore, the digital magnification range provided by the digital zoom of digital imaging system 26 is limited by the focal length of secondary objective lens 22. For example, if the focal length of secondary lens 22 is 100 mm and the digital zoom capability of digital imaging system 26 is 5×, then the total digital magnification range of digital imaging system 26 is equivalent to that of an objective lens having a focal length in a range of 100 mm-500 mm.
FIG. 1B schematically illustrates a different prior art digital imaging telescope 110. Digital imaging telescope 110 is similar to digital imaging telescope 10, except that digital imaging telescope 110 uses a single objective lens 114 to provide light to eyepiece 118 and to digital imaging system 126. This light sharing is accomplished in digital imaging telescope 110 by a beam splitter 134 and a flat mirror 128. Beam splitters are well known optical devices and can be fabricated by providing a partially reflective coating between a pair of triangular prisms. Light from optical path 130 which impinges on beam splitter 134 is split into a first component 130A, which continues onward through erecting prism 116 to eyepiece 118 (point F1), and a second component 130B, which emerges from beam splitter 134 at a 90° angle, reflects from flat mirror 128 and then travels to digital imaging system 126 (point F2).
While beam splitter 134 eliminates the need for a second objective lens, the introduction of beam splitter 134 splits the light that is collected by objective lens 114 (i.e. into components 130A, 130B). Consequently, components 130A and 130B each contain only a fraction of the light that is collected by objective lens 114. For a given objective lens 114, the introduction of beam splitter 134 reduces the amount of light available at eyepiece 118, which in turn reduces brightness, contrast and resolution.
Because the index of refraction of the glass used in beam splitter 134 (nglass) is greater than that of air (nair≈1), the introduction and/or withdrawal of beam splitter 134 into light path 130 also changes the optical path length of light traveling between objective lens 114 and eyepiece 118 and between objective lens 114 and digital imaging system 126. Assuming that the thickness of an optical path through beam splitter 134 is L, then the optical path length through beam splitter 134 will be OPLsplitter=L/nglass and the reduction in optical path length caused by the introduction of beam splitter 134 will be ΔOPL=L−L/nglass. Assuming nglass=1.5, this results in OPLsplitter=0.67L or a reduction in optical path length of ΔOPL=L−0.67L=0.33L.
Furthermore, telescope 110 suffers from the same limitations as telescope 10 with respect to its digital magnification range. The digital magnification range provided by the digital zoom of digital imaging system 126 is limited by the focal length of objective lens 114. Another drawback with telescope 110 is that the partially reflective surface of beam splitter 134 can cause a loss of true color and scattering which can induce light decay.
There is a general desire to provide optical imaging systems which address or ameliorate some of the disadvantages discussed above.

Beam splitter and optical imaging systems incorporating same


A camcorder integrally incorporating a still camera and using an automatic focusing device of the still camera or the camcorder is provided. A still camera main body and an optical viewfinder of the still camera are installed at the right front side of the main body of a camcorder, and a still camera lens, an infrared emitting element for measuring distance, an infrared receiving element for measuring distance, a flash and the like are installed at the main body of the still camera. Therefore, when a focus of an object is difficult to control, e.g., when the object is in the dark or when there is no contrast between the object and the background, the focusing direction of the camcorder lens is moved using the data of distance measured by a distance measuring device adopting an infrared mode installed in the still camera, so that a picture photographed by an instant camera function or a frash recording function can be stored in the picture memory of the camcorder.

The present invention relates to a camcorder having a still camera integrally formed therein, and more particularly to a camcorder integrally incorporating a still camera in which a camcorder portion using a magnetic tape as the recording medium and a still camera portion using a photographic film as the recording medium are integrally formed in one body, and a distance measuring device of the camera controls the focus of the camcorder and vice versa.
A camcorder for magnetically recording a moving picture on a magnetic tape and a still camera for forming a still picture by exposing a photographic film to light reflected from an object have each been developed as separate apparatuses. In order to record an object magnetically and photographically using both the camcorder and the still camera, one must bear the inconvenience of having to carry both the camcorder and the still camera for the duration of the photographing/recording period. Also, the camcorder must be paused or stopped in order to take a picture using the still camera.
To alleviate the above inconveniences, a camcorder in which a still camera is integrally formed has been developed. However, there are several problems due to the lenses of the still camera and the camcorder being separated and working independently. First, due to the difference in the view of an object as seen through the picture-taking lens of the still camera and the view as seen through a separate viewfinder or monitor of the camcorder, parallax occurs. Thus, when photographing an object using the still camera while viewing an object displayed on a monitor focused by the camcorder, or recording the object using the camcorder while viewing the object through an optical viewfinder focused by the a still camera, there is a conflict of focus. Also, assuming that the objects recorded by the camcorder is displayed on a liquid crystal display (LCD) installed at the rear side, it is difficult to determine the viewing angle of the still camera when viewing the LCD in order to focus on the same object since the automatic focus (AF) devices for the camcorder and the still camera work independently. Another problem is that the AE device of the camcorder adopts an algorithm for maximizing a high frequency component of a picture signal. Therefore, it is difficult to focus when the picture signal is weak, for example, when an object to be photographed is dark or when there is little or no contrast (ratio of lightness to darkness) between the object and the background. Furthermore, since the AF device of the camcorder has a long time constant, it is impossible to measure distance in the near instant time span of illumination during flash photography. Especially, when intending to store a picture in a picture memory with the picture being captured by the camcorder using the flash in dark situations, it is impossible to focus on the object by operating the AF device of the camcorder prior to the illumination by the flash.

Camcorder integrally incorporating a still camera


An exemplary constant velocity joint includes a first member and a second member rotatably engaging the first member. A clutch pack is disposed between and engages the first and second members. A fastener is used to attach the first member to the second member. The fastener is fixedly connected to the second member and rotatably engages the first member. The fastener exerts a biasing force for urging the first and second members into engagement with the clutch pack.

Constant velocity joints connecting shafts to drive units are common components in vehicles. The drive unit typically has an output shaft or an input shaft for receiving the joint. Typically, the drive unit is an axle, transfer case, transmission, power take-off unit, or other torque device, all of which are common components in automotive vehicles. Typically, one or more joints are assembled to the shaft to form a propeller or drive shaft assembly. It is the propeller shaft assembly which is connected, for instance, at one end to the output shaft of a transmission and, at the other end, to the input shaft of a differential. The shaft may be solid or tubular with ends adapted to attach the shaft to an inner race of the joint thereby allowing an outer race connection to a drive unit. The inner race of the joint is typically press-fit, splined, or pinned to the shaft making the outer race of the joint available to be bolted or press-fit to a hub connector, flange or stubshaft of the particular drive unit. At the other end of the propeller shaft, the same typical or traditional connection is made to a second drive unit when connecting the shaft between the two drive units. Optionally, the joint may be coupled to a shaft for torque transfer utilizing a direct torque flow connection.
In many off road vehicle environments considerable torque is applied through the constant velocity joint. All terrain vehicles and utility vehicles often have drivelines that are subject to intermittent high torque values during unusual or extreme operating conditions. Such operating conditions may arise, for example, when the vehicle lands after jumping off irregular terrain. The impact upon landing generates considerable torque in the drivelines. This torque is subsequently imparted into the individual components of the constant velocity joint as the wheels of the vehicle regain traction. When the torque imparted into the constant velocity joint components exceeds design considerations, the components can experience failure. A common design response to these extreme conditions has been to increase the size of the CV joint components in order to increase their maximum torque weathering capacity.
In addition to the extreme conditions, designers are utilizing higher capacity engines in vehicle designs. These higher capacity engines increase the power passed through the drivelines and therefore increase the overload torques experienced during extreme conditions. Existing methods of compensation require continued upsizing of the drivelines in order to accommodate the increased power and resulting increased overload torques. Continued upsizing, however, results in increases in mass of the driveline components with subsequent mass increases to the vehicle itself. Upsizing, therefore, poses undesirable restrictions on vehicle designers.

Constant velocity joint with torque overload protection


Systems and methods are provided for generating inferred reviews of service providers. Inferred reviews may be generated based on user behavior data for one or more users. The user behavior data may include information that represents how far a user travels to a service provider, how many similar service providers the user passes on the way to the service provider, a number of repeat visits to the service provider, a typical time for services at the service provider, or a length of time the user has been a customer or attendee of the service provider. A service provider may include a merchant, a hotel, a physician, a contractor, another service provider that provides goods or services for a cost or may include non-profit service providers, charity-based service providers or public locations such as parks, rest stops or other locations.

It has become common for prospective customers of a business who are also users of a network such as the Internet to access online reviews of the business prior to use. The online reviews are typically posted by previous customers who are either exceedingly happy or exceedingly unhappy with the business. However, online reviews can be misleading and/or biased. It can be inconvenient for a typical customer to write and post a review of a particular business. For this reason, it is often customers with the most extreme positive or negative opinions that take the time to write and post the review. It would therefore be desirable to be able to provide improved networked systems and associated methods for rating service providers.
Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, wherein showings therein are for purposes of illustrating embodiments of the present disclosure and not for purposes of limiting the same.


A perfluoropolyether, a composition comprising the perfluoropolyether, a process for producing the perfluoropolyether, and a process for improving the thermostability of grease or lubricant are provided. The perfluoropolyether comprises perfluoroalkyl radical end groups in which the radical has at least 3 carbon atoms per radical and is substantially free of perfluoromethyl and perfluoroethyl end groups. The process for producing the perfluoropolyether can comprise (1) contacting a perfluoro acid halide, a C2-to C4-substituted ethyl epoxide, or a C3+ fluoroketone with a metal halide to produce an alkoxide; (2) contacting the alkoxide with either hexafluoropropylene oxide or tetrafluorooxetane to produce a second acid halide; (3) esterifying the second acid halide to an ester; (4) reducing the ester to its corresponding alcohol; (5) converting the alcohol with a base to a salt form; (6) contacting the salt form with a C3 or higher olefin to produce a fluoropolyether; and (7) fluorinating the fluoropolyether. The process for improving the thermostability of a grease or lubricant comprises combining the grease or lubricant with the composition.

Hereinafter trademarks or trade names are shown in upper case characters.
Perfluoropolyethers (hereinafter PFPE) are fluids having important uses in oils and greases for use under extreme conditions. A property shared by the class is extreme temperature stability in the presence of oxygen and they find use in tribological or lubrication applications. Among their advantages as extreme lubricants is the absence of gums and tars among the thermal decomposition products. In contrast to the gum and tar thermal degradation products of hydrocarbons, the degradation products of PFPE fluids are volatile. In actual use, the upper temperature limit is determined by the stability of the oil or grease. Lewis acids, metal fluorides such as aluminum trifluoride or iron trifluoride, are formed as a result of heat at microscale loci of metal to metal friction; for instance as stationary bearings are started in motion. Thus the PFPE stability in the presence of the metal fluoride, although lower than the stability in the absence of the metal fluoride, establishes the upper performance temperature. The three commercial PFPEs, KRYTOX (from E.I. du Pont de Nemours and Company, Inc., Wilmington Del.), FOMBLIN and GALDEN (from Ausimont/Montedison, Milan, Italy) and DEMNUM (from Daikin Industries, Osaka, Japan) differ in chemical structure. A review of KRYTOX is found in Synthetic Lubricants and High-Performance Fluids, Rudnick and Shubkin, Eds., Marcel Dekker, New York, N.Y., 1999 (Chapter 8, pp. 215-237). A review of FOMBLIN and GALDEN is found in Organofluorine Chemistry, Banks et al., Eds., Plenum, New York, N.Y., 1994, Chapter 20, pp. 431-461, and for DEMNUM, in Organofluorine Chemistry (op. cit.), Chapter 21, pp. 463-467.
The anionic polymerization of hexafluoropropylene epoxide as described by Moore in U.S. Pat. No. 3,332,826 can be used to produce the KRYTOX fluids. The resulting poly(hexafluoropropylene epoxide) PFPE fluids are hereinafter described as poly(HFPO) fluids. The initial polymer has a terminal acid fluoride, which is hydrolyzed to the acid followed by fluorination. The structure of a poly(HFPO) fluid is shown by Formula 1:CF3—(CF2)2—O—[CF(CF3)—CF2—O]S—Rf  (Formula 1)where s is 2-100 and Rf is a mixture of CF2CF3 and CF(CF3)2, with the ratio of ethyl to isopropyl terminal group ranging between 20:1 to 50:1.
DEMNUM fluids are produced by sequential oligomerization and fluorination of 2,2,3,3-tetrafluorooxetane (tetrafluorooxetane), yielding the structure of Formula 2.F—[(CF2)3—O]t—Rf2   (Formula 2)where Rf2 is a mixture of CF3 or C2F5 and t is 2-200.
A common characteristic of the PFPE fluids is the presence of perfluoroalkyl terminal groups.
The mechanism of thermal degradation in the presence of a Lewis acid such as aluminum trifluoride has been studied. Kasai (Macromolecules, Vol. 25, 6791-6799, 1992) discloses an intramolecular disproportionation mechanism for the decomposition of PFPE containing —O—CF2—O— linkages in the presence of Lewis acids.
FOMBLIN and GALDEN fluids are produced by perfluoroolefin photooxidation. The initial product contains peroxide linkages and reactive terminal groups such as fluoroformate and acid fluoride. These linkages and end groups are removed by ultraviolet photolysis and terminal group fluorination, to yield the neutral PFPE compositions FOMBLIN Y and FOMBLIN Z represented by Formulae 3 and 4, respectivelyCF3O(CF2CF(CF3)—O—)m(CF2—O—)n—Rf3   (Formula 3)where Rf3 is a mixture of —CF3, —C2F5, and —C3F7; (m+n) is 8-45; and m/n is 20-1000; andCF3O(CF2CF2—O—)p(CF2—O)qCF3   (Formula 4)where (p+q) is 40-180 and p/q is 0.5-2. It is readily seen that Formulae 3 and 4 both contain the destabilizing —O—CF2—O— linkage since neither n nor q can be zero. With this —O—CF2—O— linkage in the chain, degradation within the chain can occur, resulting in chain fragmentation.
For PFPE molecules with repeating pendant —CF3 groups, Kasai discloses the pendant group provides a stabilizing effect on the chain itself and for the alkoxy end groups adjacent to a —CF(CF3)—. Absent the —O—CF2—O— linkage, the PFPE is more thermally stable, but its eventual decomposition was postulated to occur at end away from the stabilizing —CF(CF3)— group, effectively unzipping the polymer chain one ether unit at a time.
Therefore, there is substantial interest and need in increasing the thermal stability of PFPE fluids.

Thermally stable perfluoropolyethers and processes therefor and therewith


Novel polypropylene films are prepared from a composition comprising polypropylene and an N,N-N,Nxe2x80x2-bis-alkylene fatty amide having the general structural formula Rxe2x80x94COxe2x80x94NHxe2x80x94(CH2)nxe2x80x94NHxe2x80x94COxe2x80x94Rxe2x80x2 wherein R and Rxe2x80x2 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms, n is an integer from 2 to 4 and xe2x80x94COxe2x80x94 is a carbonyl group. Such films are found to have improved utility for gravure printing applications.

This invention relates to a novel polypropylene composition having specific utility in the manufacture of oriented polypropylene films and to polypropylene films prepared therewith. More specifically, it relates to polypropylene compositions containing certain fatty acid amides not heretofore known to be useful as components in polypropylene compositions.
In the manufacture of polypropylene films, it is common practice to include, in the polymer formulation, additives referred to as slip agents. These additives migrate to the surface of the film and decrease the coefficient of friction between the film and the metal rollers over which it is passed during processing, thus facilitating the processing of the film. They also decrease the coefficient of friction between layers of the film when it is wound into rolls thereby facilitating unwinding of the rolls for further processing.
The slip additives employed in most commercial polypropylene films are relatively high molecular weight fatty acid amides. The most widely used fatty acid amides are erucamide, an unsaturated 22 carbon amide (13-docosenamide) and behenamide (docosanamide), the saturated analogue of erucamide. Both of these compounds are readily available, naturally occurring materials. They are normally provided as mixtures containing a small amount of other amides containing about 18 to 20 carbons.
Erucamide works quite well as a slip agent, but it is not favored by some producers and converters as it is relatively volatile and extra care is required during film manufacture and conversion to avoid having quantities of the additive escape from the film and plate out on processing equipment, thereby causing a clean-up problem. For this reason, some producers prefer to use behenamide as the slip agent. As slip agents, erucamide and behenamide appear to perform substantially equally well but behenamide is less volatile and therefore films containing behenamide are easier to handle during processing since the behenamide does not escape and plate out on the processing equipment.
Despite the inconveniences encountered with erucamide-containing film, erucamide is the fatty acid amide slip agent of choice for those who wish to print the film using the well known rotogravure printing technique. In the rotogravure process, ink is applied to the print surface from a gravure cylinder containing the desired image as depressions on its surface. Ink is applied to the cylinder and the surface of the cylinder is wiped by a doctor blade to remove excess ink. The film to be printed is then contacted by the gravure cylinder and the image is thus transferred from the cylinder to the film. While the film is in contact with the cylinder, a small amount of erucamide is deposited on the raised portion of the cylinder. Since erucamide is soluble in the alcohol or ketone ink solvent, it is dissolved by the solvent in the next application of ink and is removed by the next swipe of the doctor blade. Thus, no build-up of erucamide occurs on the doctor blade or on the gravure cylinder.
Behenamide, on the other hand, lacking the carbon-carbon unsaturation found in erucamide, is substantially less soluble in the alcohols and ketones found in printing inks. Thus, when, in the course of rotogravure printing, some of the behenamide is deposited on the printing cylinder, it is not dissolved in the printing ink and wiped off when the next application of ink and wiping by the doctor blade takes place. As a result, the behenamide is merely wiped off by the next swipe of the doctor blade and substantially all of it remains on the blade. After multiple swipes of the blade, a behenamide build-up forms on the doctor blade and on the printing cylinder, eventually reaching a point at which the blade is prevented from wiping the surface of the printing cylinder clean. This build-up causes streaks to form on the printed film, requiring an interruption of the job in order to clean the doctor blade.
It will be immediately apparent that a slip additive that does not cause the film processing problems associated with erucamide but which allows the film to be rotogravure printed without causing the problems associated with behenamide would be a welcome contribution to the polypropylene film art. In accordance with this invention, there has been discovered a slip additive that accomplishes this objective.
It is an objective of this invention to provide oriented polypropylene films that exhibit improved properties in rotogravure printing as compared to films presently known to the art. It is likewise an objective of this invention to provide film-forming compositions for preparing such films.
In accordance with this invention, it has been found that certain bis-fatty acid amides exhibit a combination of properties that makes them highly satisfactory as slip agents in oriented polypropylene films. In particular, this combination of properties make them highly satisfactory as slip agents in films that are to be printed in rotogravure printing operations.
Briefly stated, the invention is a composition comprised of a polymer or copolymer of propylene and an N,Nxe2x80x2-bis-alkylene fatty acid amide having the general structural formula Rxe2x80x94COxe2x80x94NHxe2x80x94(CH2)nxe2x80x94NHxe2x80x94COxe2x80x94Rxe2x80x2 wherein R and Rxe2x80x2 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms xe2x80x94COxe2x80x94 is a carbonyl group and n is an integer from 2 to 4 said N,Nxe2x80x2-bis alkylene fatty acid amide being present in an amount from about 0.05 to about 0.5% by weight based on the combined weight of said amide and the polypropylene.
In another aspect, the invention contemplates an oriented film comprised of a polymer or copolymer of propylene and an N,Nxe2x80x2-bis-alkylene fatty amide having the general structural formula Rxe2x80x94COxe2x80x94NHxe2x80x94(CH2)nxe2x80x94NHxe2x80x94COxe2x80x94Rxe2x80x2 wherein R and Rxe2x80x2 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms, n is an integer from 2 to 4 and xe2x80x94COxe2x80x94 is a carbonyl group said N,Nxe2x80x2-bis alkylene fatty acid amide being present in an amount from about 0.05 to about 0.5% by weight based on the combined weight of said amide and the polypropylene.
A preferred embodiment of the invention is a composite film comprised of a polypropylene core having, on at least one of its surfaces, a film layer comprised of a composition comprising polypropylene and up to about 0.5% of an N,Nxe2x80x2-bis-alkylene fatty amide having the general structural formula Rxe2x80x94COxe2x80x94NHxe2x80x94(CH2)nxe2x80x94NHxe2x80x94COxe2x80x94Rxe2x80x2 wherein R and Rxe2x80x2 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms, n is an integer from 2 to 4 and xe2x80x94COxe2x80x94 is a carbonyl group, said N,Nxe2x80x2-bis alkylene fatty acid amide being present in an amount from about 0.05 to about 0.5% by weight based on the combined weight of said amide and the polypropylene.
As used in the description of this invention and in the attached claims, the term xe2x80x9cfilmxe2x80x9d refers to a stand-alone film, i.e. a film of a sufficient thickness to have the strength and other characteristics required to have utility in packaging and other applications without having to be united with another film to support it. Stand-alone monolayer films are seldom seen in commerce. However, the compositions of the invention are suitable for use in such films.
Oriented polypropylene films of commerce are usually composite, i.e. multilayer, structures in which a core layer of a thickness sufficient to impart stand-alone properties to the overall structure carries one or more thin functional layers on its surface(s). The term xe2x80x9cfilmxe2x80x9d will also be used to refer to these thin functional layer films although they do not have sufficient thickness to stand alone.
Composite polypropylene films are typically comprised of a homopolypropylene core having one or more functional layers on its surfaces. Functional layers can act, e.g., as heat or cold seal layers, as receiving layers for printing or other decorative material or as barrier coating receiving layers. In these cases, it is not required that the polymer in the surface layer be the same as that employed in the core, although it may be the same polymer formulated differently to serve the functional role that it is to serve in the completed film. Frequently, the surface layer will be of a different polymer that has been found to perform the desired function more satisfactorily than would the polymer employed in the core.
When reference is made herein to polypropylene, it is intended to indicate a crystalline (isotactic) propylene homopolymer or a copolymer of propylene with ethylene or an xcex1-olefin having 2 to 5 carbon atoms in an amount insufficient to have a significant effect on the crystallinity of the polypropylene. Typically, the comonomer will be ethylene in an amount of 6% or less.
Suitable polypropylenes are the commercially available isotactic polypropylenes having a melt flow rate between about 2 and about 10 dg/10 min at 230xc2x0 C. and 2.16 Kg. load and a DSC melting point of about 160 to 166xc2x0 C. One polypropylene that can be used is the isotactic homopolymer having a melt flow rate of about 3.5 dg/1 0 min at 230xc2x0 C. and 2.16 Kg. load, available from Aristech Chemical Corporation, Pittsburgh, Pa. Suitable polypropylenes are also available from Montell, Inc. Wilmington, Del., Exxon Chemical Company, Baytown, Tex. and Fina Oil and Chemical Co., Deer Park, Tex.
Since different layers are formulated differently, it is possible that different slip agents may be used in the different layers or that some layers contain no slip agent. Thus, it is possible and desirable, in cases where problems are encountered when using conventional slip agents, e.g. in the rotogravure printing process as described above, to limit the use of the bis-amides of the invention to the functional layer where its presence yields the desired advantage. In such cases, where in the past the conventional slip agents have been added to the core layer and allowed or forced to migrate into the functional layers, it is found that the presence of the bis amides almost completely prevents the migration of the conventional slip agent, e.g. erucamide or behenamide from the core to the functional layer where it can cause a problem.
The slip additives employed in the compositions and oriented films according to this invention are N,Nxe2x80x2-bis- fatty acid amides having the general structural formula Rxe2x80x94COxe2x80x94NHxe2x80x94(CH2)nxe2x80x94NHxe2x80x94COxe2x80x94Rxe2x80x2 wherein R and Rxe2x80x2 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms, n an integer from 2 to 4 and xe2x80x94COxe2x80x94 is a carbonyl group. The compounds employed in the compositions of this invention are characterized by having a relatively low degree of volatility and a relatively high degree of solubility in alcohols, ketones and esters.
Compounds meeting the above definition and description include, by way of example, N,Nxe2x80x2bis-ethylene stearamide, N,Nxe2x80x2-bis ethylene oleamide, N,Nxe2x80x2-bis ethylene behenamide, N,Nxe2x80x2-bis ethylene erucamide, N,Nxe2x80x2-bis propylene stearamide, N,Nxe2x80x2bis butylene oleamide.
The N,Nxe2x80x2-bis-alkylene fatty acid amide is present in the compositions of the invention in a concentration of about 0.05 to about 0.5% by weight based on the total weight of the composition. Preferably, the concentration of the slip additive is between about 0.05 and about 0.25% and most preferably between about 0.5 and about 0.2%.
The slip agents of the prior art such as erucamide or behenamide are sufficiently volatile that a measurable portion of them always migrates from the interior of the film and forms a layer of slip agent on the film""s surface, whether the film is a composite or a monolayer. The amount present on the surface can be measured by a technique referred to as Attenuated Total Reflectance Infra-Red Spectroscopy (ATRIR). When the ATRIR spectrum of a film sample stored at room temperature is compared to that of a film stored for 16 hours at 55xc2x0 C., an increase in the amount of a prior art slip agent is detected. (Such heat aging is commonly applied to simulate film aging conditions.) The amount of the slip agents of this invention that migrates to the surface of a film cannot be measured by ATRIR. Their presence on the film surface is demonstrated only by their efficacy as slip agents.
The presence of conventional slip agents on the surface of a film can also be detected by rinsing the film surface with a solvent and testing for the slip agent by High Pressure Liquid Chromatography. Similarly, no accumulation of the slip agent of the invention can measured on the film surface by this technique, whereas it is readily detected in the solvent employed to wash the surface of a prior art film.
In prior art practice, slip agent is frequently incorporated into the core layer of composite films, which are then heat treated to force it to migrate to the surface layers. In other cases, if the slip agent is present only in a surface layer, it tends to migrate into the core layer although, as a rule, it is not needed there. In either case, this migratory tendency results in slip agent being present in locations where it is not needed. Moreover, it also requires the use of greater quantities of slip agent than are needed in order to assure that sufficient quantities are present in the area where the real need exists.
It has been found that the slip agents of this invention exhibit a very low tendency to migrate between layers or even within a layer of the film. Thus, a slip agent incorporated in a surface layer does not migrate into the core layer, nor does it migrate and accumulate on the surface of a layer as do the slip agents of the prior art. When tested by the ATRIR test or the surface rinse procedure mentioned above no accumulation of the slip agent is detected on the surfaces. The low migratory character of these slip agents causes them to remain in the layer into which they are incorporated.
Despite the absence of measurable amounts of the slip agent on the film surface, the slip agents of the invention are substantially equal to those of the prior art in decreasing the coefficient of friction (COF) of the film surface. Thus, the COF measured on the surface of a prior art film containing erucamide as the slip agent is about 0.15 to 0.35. That measured on a prior art film containing behenamide is about 0.15 to 0.35. The COF measured on the surface of a film of this invention is generally between about 0.15 and about 0.45.
The low migratory character of the slip agents of the invention also leads to other favorable effects on film processing. For example, the problem of vaporization encountered with erucamide and to a lesser extent with behenamide is eliminated. Also, as will be apparent from the above, in the preparation of composite films, it is not always necessary to have a slip agent in the core layer. Since the slip agent of the invention will not migrate into the core layer, one can put only the amount actually needed to give the desired slip properties in the surface layer and it will not migrate into the core layer and reduce the level in the surface layer below that required to give the surface of the film the proper slip quality.
As indicated hereinabove, the compositions of the invention have particular utility in the manufacture of rotogravure printable oriented polypropylene film thanks to the unique combination of good alcohol, ketone and ester solubility and low volatility exhibited by the N,Nxe2x80x2-bis-alkylene fatty acid amides. Due to their low degree of volatility, these compounds do not vaporize from the surface of the film during manufacturing and conversion. Due to their relatively high degree of solubility in the solvents that are normally employed as solvents for printing inks, whatever small amounts these compounds that might be on the film surface does not form a build-up on the doctor blade during rotogravure printing. Films prepared using these compositions thus combine the favorable properties of conventional films containing behenamide during the manufacture and conversion of the film with the favorable properties of those containing erucamide for use in rotogravure printing.
In yet another aspect, the slip agents employed in the films of the invention are found to be improved candidates for use as cold seal films. Cold seal films are prepared by treating the films with a cold sealable adhesive such as a rubber cement and many applications for printed films are applications in which cold seals are preferred over more conventional heat seals. In prior art usage, particularly when erucamide is employed as the slip agent, it is found that the high level of the slip agent on the film surface weakens or even, in extreme cases, destroys cold sealability. Using the slip agents of this invention at the levels specified, very little or no harmful effect on cold seal is seen.
In addition to the slip agents of this invention, conventional additives, in conventional amounts, can also be included in the films. Suitable conventional additives include, by way of example, antioxidants, pigments, orientation stress modifiers, flame retardants, antistatic agents, antiblocking agents, and antifoggants. Any such additives that do not interfere with the functioning of the slip agent can be present.
In any embodiment of the films of the invention, the film can be either clear and transparent or it can be opaque. Typically, polypropylene films are rendered opaque by loading the core layer with a void forming opacifier such as calcium carbonate. Such opacifiers cause opacity by forming microvoids in the polymer matrix during the drawing operation. Other types of opacifiers which cause opacity simply by increasing the optical density without voiding can also be employed. Typical of such an opacifier is titanium dioxide.
The total film thickness, for either the single or multiple layer films, is preferably in the range of about 0.25 to about 1.5 mil, i.e. about 25 to about 150 gauge. In the multilayer embodiment, the core layer preferably has a thickness of about 23 to about 40 gauge, while the other layers preferably each have a thickness of about 2 to about 10 gauge.
To prepare a printable surface, the surface of the film that is to be printed is subjected to an oxidation treatment to impart a degree of polarity to the surface, which ensures good adhesion of the printed information to the film. Suitable oxidation treatments include, by way of example, corona discharge, flame and acid etching. The preferred treatment is with corona discharge or with flame. The use of flame and corona, seriatim, is also known and frequently employed.
The oxidation treatment is preferably carried out to a degree sufficient to create a surface tension on the film surface equal to about 35 to about 60 dynes/cm. A preferred surface tension is about 35 to about 40 dynes/cm.
As stated hereinabove, composite films can have, in addition to the printable surface, other functional layers on the surface opposite the print layer. If the layer on the side opposite the print layer is a barrier coating receiving layer, that layer will also be subjected to an oxidation treatment to approximately the same degree as is applied to the print layer.
While the invention has been described with emphasis on its utility in rotogravure printing, it will be apparent that other types of films, including functional layers, can also benefit from the low volatility and the lower degree of migratory tendency of the slip agents of the invention. One type of such film is metallizable film where the greater migratory tendency and volatility of conventional slip agents tends to result in a greater amount of slip agent on the film surface, which can sometimes interfere with bonding of the metal coating to the film surface. The same effect is also noted with cold seal coatings applied to the film surface.
Polypropylene films according to the invention can be prepared using film forming and orientation methods and techniques well known to the plastic film art. Thus the films can be prepared using the tubular or bubble process wherein a tube of film is extruded through a circular die and is drawn and inflated simultaneously to effect biaxial orientation. Likewise, they can be prepared by the tenter process in which a flat sheet of the film is drawn from the die at a multiple of the lineal rate of extrusion to effect longitudinal orientation and is thereafter drawn laterally by a preselected multiple of its original width to effect lateral orientation. As a rule, films prepared by the bubble process are drawn uniformly 6xc3x97 by 6xc3x97 or 7xc3x97 by 7xc3x97. When the tenter process is employed, the draw is usually carried out to 5xc3x97 in the machine direction and 10xc3x97 in the cross direction. These draw ratios are also suitable for the films of the invention, although other ratios can be employed if desired.

Slip agents and polypropylene films prepared therefrom


A battery includes an anode, a cathode, and a polymer matrix electrolyte (PME) separator disposed between the anode and the cathode. The PME separator includes a polyimide, at least one lithium salt in a concentration of at least 0.5 moles of lithium per mole of imide ring provided by the polyimide, and at least one solvent intermixed. The PME is generally homogeneous as evidenced by its high level of optically clarity. The battery can be a lithium ion or lithium metal battery.

The demand for new and improved electronic devices, such as cellular phones, notebook computers and compact camcorders, has demanded energy storage devices having increasingly higher specific energy densities. For example, the telecommunication industry is actively seeking alternate energy storage devices for its outside plant back-up power sources for telecommunication stations to replace the current standard valve-regulated lead acid batteries. Moreover, the automotive industry is in need of high specific energy density batteries for the developing electric and hybrid vehicles market. A number of advanced battery technologies have recently been developed to service these devices and markets, such as metal hydride (e.g., Ni-MH), nickel-cadmium (Ni—Cd), lithium batteries with liquid electrolytes and recently, lithium batteries with polymer electrolytes.
Lithium batteries have been introduced into the market because of their high energy densities. Lithium is atomic number three on the periodic table of elements, having the lightest atomic weight and highest energy density of any solid material. As a result, lithium is a preferred material for batteries, having very high energy density. Lithium batteries are also desirable because they have a high unit cell voltage of up to approximately 4.2 V, as compared to approximately 1.5 V for both Ni—Cd and Ni-MH cells.
Lithium batteries can be either lithium ion batteries or lithium metal batteries. Lithium ion batteries intercalate lithium ions in a host material, such as graphite, to form the anode. On the other hand, lithium metal batteries use metallic lithium or lithium alloys for the anode.
The electrolyte used in lithium batteries can be a liquid or a polymer based electrolyte. Lithium batteries including liquid electrolytes have been on the market for several years. Lithium ion rechargeable batteries having liquid electrolytes are currently mass produced for applications such as notebook computers, camcorders and cellular telephones. However, lithium batteries having liquid electrolyte technology have several major drawbacks. These drawbacks relate to cost and safety and stem from use of a liquid electrolyte. The liquid electrolyte generally requires packaging in rigid hermetically sealed metal "cans" which can reduce energy density. In addition, for safety reasons, lithium ion rechargeable batteries and lithium-metal primary batteries having liquid electrolytes are designed to vent automatically when certain abuse conditions exist, such as a substantial increase in internal pressure which can be caused by internal or external overheating. If the cell is not vented under extreme pressure, it can explode because the liquid electrolyte used in liquid Li cells is extremely flammable.
Lithium batteries having solid polymer electrolytes represent an evolving alternative to lithium batteries having liquid electrolytes. Solid polymer electrodes are generally gel type electrolytes which trap solvent and salt in pores of the polymer to provide a medium for ionic conduction. Typical polymer electrolytes comprise polyethylene oxide (PEO), polyether based polymers and other polymers which are configured as gels, such as polyacrylonitrile (PAN), polymethylmethacrylate (PMMA) and polyvinylidine fluoride (PVDF). The polymer electrolyte generally functions as a separator, being interposed between the cathode and anode films of the battery.
Because its electrolyte is generally a non-volatile material which does not generally under normal operating conditions leak, a lithium battery having a polymer electrolyte is intrinsically safer than a lithium battery having a liquid electrolyte. Moreover, polymer electrolytes eliminate the need for venting and package pressure control which are generally required for operation of lithium batteries having liquid electrolytes. Thus, polymer electrolytes make it possible to use a soft outer case such as a metal plastic laminate bag, resulting in improvement in weight and thickness, when compared to liquid electrolyte can-type Li batteries.
Each cathode, separator and anode combination forms a unit battery cell. Practical lithium batteries, such as those having polymer electrolytes, are generally prepared by stacking a number of battery cells in series and/or parallel to achieve desired battery capacity.
Lithium metal polymer (LMP) rechargeable batteries offer improved performance as compared to Li ion batteries, particularly higher capacity. LMP batteries result from the lamination/assembly of three types of main thin films: a film of positive electrode comprising a mixture of a polymer and an electrochemically active material such as lithium vanadium oxide, an electrolyte film separator made of a polymer and a lithium salt, and a negative electrode film comprising metallic lithium or a lithium alloy. A known limitation of LMP batteries, especially for automotive applications is that the polymers presently used provide their peak ionic conductivity at elevated temperatures. These LMP batteries must therefore be heated to produce peak power output.
A problem with Li metal and lithium alloy batteries is that lithium, in its metallic form, is highly reactive. As such, it presents unique difficulties in rechargeable configurations. Repeated charge/discharge cycles can cause a build-up of surface irregularities on the lithium metal electrode. External pressure is generally necessary for prolonged performance of a lithium metal battery.
These irregular structures, known as dendrites, can grow to such an extent that they penetrate the separator between positive and negative electrodes and create an internal short circuit. At best, this phenomenon shortens the useful life of a rechargeable Li-metal battery to generally about 900 cycles or less.
Many performance parameters of lithium batteries are associated with the electrolyte choice, and the interaction of the selected electrolyte with the cathode and anode materials used. High electrolyte ionic conductivity generally results in improved battery performance. The ionic conductivity of gel polymer electrolytes have been reported to be as high as approximately 10−4 S/cm at 25° C. However, it is desirable for the ionic conductivity of the polymer electrolyte to reach even higher values for some battery applications. In addition, it would also be desirable to enhance the electrochemical stability of the polymer electrolyte towards anode and cathode materials to improve battery reliability, as well as storage and cycling characteristics.
While gel polymer electrolytes represent an improvement over liquid electrolytes in terms of safety and manufacturability, safety issues remain because gel polymers trap solvent on its pores and under extreme conditions (e.g. heat and/or pressure) can still escape and cause injury. In addition, gel polymer electrolytes cannot generally operate over a broad temperature range because the gel generally freezes at low temperatures and reacts with other battery components or melts at elevated temperatures. Moreover, electrode instability and resulting poor cycling characteristics, particularly for metallic lithium containing anodes, limits possible applications for such batteries formed with gel polymer electrolytes.
Alternative polymer materials have been actively investigated to provide improved characteristics over available polymer choices. For example, U.S. Pat. No. 5,888,672 to Gustafson et al. ('672 patent) discloses a polyimide electrolyte and a battery formed from the same which operates at room temperature and over a broad range of temperatures. The polyimides disclosed are soluble in several solvents and are substantially amorphous. When mixed with a lithium salt, the resulting polyimide based electrolytes provide surprisingly high ionic conductivity. The electrolytes disclosed in '672 are all optically opaque which evidences some phase separation of the various components comprising the electrolyte. Although the electrolytes disclosed by the '672 patent can be used to form a polymer electrolyte and a battery therefrom which provides an improved operating temperature range, ease of manufacture, and improved safety over batteries formed from conventional gel polymer electrolytes, it would be helpful if the electrolyte stability over temperature and pressure as well as the ionic conductivity could be improved.

Polyimide matrix electrolyte and improved batteries therefrom


A new and distinct variety of peach tree, which has a low winter chilling requirement of approximately 250 chill units (cu). The tree is large size, highly vigorous with a semi-upright growth habit, and has showy pink flowers. Glands are small and reniform in shape and isolated to the basal portions of leaves. This tree, which has been denominated xe2x80x98UFOxe2x80x99, is a regular bearer of heavy crops which are large for the moderately early ripening season, with yellow and very firm non-melting fresh, semi-freestone fruit of peento shape. Fruit are uniform, attractive, substantially symmetrical shape, and have an attractive 50 to 70% striped red skin color. The fruit ripens 10 to 15 days after xe2x80x98UFGoldxe2x80x99 in mid- to late May at Gainesville.

The present invention relates to a new and distinct variety of peach (Prunus persica (L.) Bastch) tree named xe2x80x98UFOxe2x80x99, and more particularly to a peach tree adapted to a mild winter climate. The tree produces peento (donut, flat or saucer shape) fruit with good eating quality, semi-freestone, and yellow, non-melting flesh, maturing in mid- to late May at Gainesville. Asexual propagation was performed at Gainesville, Fla., where the selection was made, and top worked trees were fruited the past two years. Contrast is made to xe2x80x98UFGoldxe2x80x99 (U.S. Plant Pat. No. 10,315) peach, a standard variety, for reliable description and contrast. This new peento peach variety is a promising candidate for a unique fruit on the fresh market. It retains fruit firmness at the full flavor, tree ripe stage for 10 days on the tree.
This peach tree (genotype) originated in the fruit breeding program at the University of Florida, located at Gainesville, as a self-pollination of Fla. 95-10pc (non-patented), a non-melting flesh peach from the program. xe2x80x98UFOxe2x80x99 was observed with a crop in 1997, and was selected from about 30 siblings in 1998 when it bore a heavy crop and was determined to have unique tree and fruit characteristics making it worthy for commercial fresh fruit production. It was designated as Fla. 98-7pc and was asexually propagated at Gainesville as a uniform variety by topworking 3-year-old trees and by budding to young seedlings of xe2x80x98Flordaguardxe2x80x99 (non-patented) rootstock. There are no effects of this rootstock on this scion variety that are known to the inventor.
The new and distinct variety of peento peach bears yellow, non-melting flesh fruit, and has a moderate-chilling dormancy requirement estimated to be 250 chill units based on time of bloom in relation to standard varieties. xe2x80x98UFOxe2x80x99 blooms about 5 days after xe2x80x98UFGoldxe2x80x99 peach at Gainesville, bearing 50 to 70% red skin and yellow flesh fruit. When grown in subtropical climates to take advantage of its early bloom (low-chilling), xe2x80x98UFOxe2x80x99 is the first described, non-melting flesh, peento peach to ripen in the USA.
The present invention resulting in xe2x80x98UFOxe2x80x99 peach tree is characterized by non-melting flesh, peento shape, and attractive fruit of excellent flavor and eating quality on a tree adapted to mild winters. The trees are vigorous, productive, and regular bearing. Trees attain in two years, a height of three meters and a spread of two meters at Gainesville. The first fruit ripen in mid-to late May at Gainesville, about 95 days from full bloom, which is about 10 to 15 days after xe2x80x98UFGoldxe2x80x99. The fruit are uniformly large (60 to 80 g) for a peento peach. Ripe fruit have 50 to 70% red (solid and stripes) skin with small flecks of red pigment in the flesh, but no red in the flesh surrounding the pit. The flower anthers are light red to yellow, a common characteristic of many standard peach and nectarine varieties.


The invention relates to a polyol-based plasticized composition which includes a sufficient quantity of a thickening additive to obtain a viscosity at 20.degree. C. of at least 4 Pa.cndot.s. This plasticized composition can be employed for obtaining a polyurethane gel.

The term gel must be understood as describing the physical state of the final product. The terms polyurethane gel therefore refer at present to a plasticized polyurethane obtained by bringing a plasticized composition (I) based on at least one polyol into contact with at least one polyisocyanate.
For certain highly specific electrical applications such as electrical insulation or cable filling, or else for paramedical applications (antiscab mats and pads, mammary prosthesis), polyurethane gels are required which have a low consistency and which are obtained rapidly after the composition (I) has been brought into contact with a polyisocyanate.
More precisely, what is sought after is plasticized compositions (I) based on polyols which, at ambient temperature (approximately 20.degree. C.) have a high viscosity, equal to or higher than 4 Pa.cndot.s and in which the reactants (polyols) are capable of reacting with the polyisocyanate.
Known plasticized compositions contain high plasticizer ratios which are likely to lower considerably the viscosity of the said polyol-based compositions.
Thus, U.S. Pat. No. 4,787,905 describes a gel which can be employed for the manufacture of a mammary prosthesis. A low-viscosity plasticized composition is produced for this purpose, containing 10% by weight of a polydiene polyol and 90% by weight of undecyl phthalate.
Similarly U.S. Pat. No. 4,666,968 describes a low-viscosity polyurethane gel which can be employed in electrical insulation and which contains a high plasticizer content. This gel is obtained particularly by bringing a plasticized composition containing a polyisocyanate into contact with a highly plasticized composition containing polyols.
U.S. Pat. No. 5,258,578 also describes low-viscosity polyurethane gels which can be employed for cable terminals and connection boxes.

Polyol-based plasticized composition which has a controlled viscosity


A printing apparatus according to the present invention includes a printing section configured to print ink on a surface of a substrate. The printing section prints conductive ink containing a conductive material by offset printing and prints conductive ink containing a conductive material different from the conductive material on the conductive ink by offset printing. Preferably, the printing apparatus further includes a conveyor configured to convey the substrate. Further, the printing section preferably includes a first printing machine configured to print first conductive ink and a second printing machine configured to print second conductive ink.

Solar panels can convert clean and inexhaustibly-supplied solar energy directly to electric energy and therefore are expected as novel energy sources. Silicon substrates are used for current mainstream solar panels. A collector electrode containing silver is provided on the surface of a silicon substrate. With the use of silver as a material for the collector electrode, it has been attempted to reduce the contact resistance between the silicon substrate and the collector electrode and to suppress the resistance of the collector electrode itself (for example, see Japanese Unexamined Patent Application Publication No. 2009-194013).
Further, a wide width of the collector electrode provided on a light receiving side of a solar panel reduces the opening area of the silicon substrate to achieve inefficient energy conversion. Accordingly, it has been proposed to form an electrode in which a conductive layer containing silver is layered to reduce the reduction in the opening area and reduce the resistances (for example, see Japanese Unexamined Patent Application Publication No. 2010-090211). JP No. 2010-090211 discloses that a conductive layer containing silver is layered by printing to reduce the specific resistance and suppress oxidation.

Panel, method for producing panel, solar cell module, printing apparatus, and printing method


A method and apparatus for reading a software counter in a computer system that contains a plurality of processes each having access to the software counter is provided. The software counter includes a wrap portion and a base portion that cannot both be accessed in an atomic operation. The method includes the steps of reading a first value. The first value being one of the wrap or base portions. Reading a second value. The second value being the other of the wrap or base portion. Determining whether the first value might be changed during a time period that elapsed between reading the first value and reading the second value. If the first value might be changed during the time period, then obtaining a latch that covers at least the wrap portion. After obtaining the latch, reading the wrap and base portion and releasing the latch.

In most computer systems, it is desirable to maximize the processing power and throughput of the system hardware. To achieve a higher throughput, a computer system will typically increase the utilization of the hardware by executing multiple processes concurrently. Executing multiple processes concurrently enables a system to enhance its performance by increasing the utilization of the CPU and other peripheral devices.
In a concurrent processing environment, each process is simply an executing program that contains its own program counter, registers and variables. Although concurrent processes often share a disk or common memory area, each process may execute independent of the other processes. Because each process is able to execute independently, events associated with and transactions executed by the concurrent processes can complete asynchronously with respect to one another.
It is often desirable for these otherwise asynchronous events and transactions to be ordered by time of occurrence. For example, tracking the ordering of transactions that perform changes to a database is critical to maintaining the stability and consistency of the database. If data from the database needs to be reconstructed as of a designated time, it is critical to be able to distinguish between changes made by transactions that completed before the designated time and changes made by those transactions that completed after the designated time. Therefore, to maintain consistency, it is extremely important to know when each transaction completed relative to other completed transactions.
One method of ordering events in a multiprocessing system is by assigning a logical time-stamp to each event. For example, as transactions complete in a database system, a logical time-stamp may be attached to each transaction. The logical time-stamp assigned to the completion of each transaction is used by the database system to represent a logical time ordering of when the events occurred.
To effectively assign time-stamps, a mechanism for producing ever-increasing sequence numbers must be provided. A typical method for providing ever-increasing sequence number is to provide a software counter that can be accessed and incremented by each process. Thus, whenever an event occurs for a particular process, the process may increment the software counter, read the counter to obtain a specific sequence number, and attach the sequence number to the current event.
Since logical time-stamps provide only a relative ordering of events, it is not necessary that each sequence number supplied by software counter increment uniformly, but only that the current value provided by the software counter be greater than any previous value provided by the software counter. For example, if events are provided time stamps in the sequence one (1), two (2), five (5), and nine (9), it is still possible to determine the relative order in which each event occurred.
Because the logical time-stamps are relative to one another, it is critical to provide a software counter that will provide ever-increasing numbers throughout the lifetime of the concurrent processing system in which it is used. Therefore, it is often desirable and even necessary, to provide a software counter with a greater range than that provided by the bit-size of a single machine word.
For example, as depicted in FIG. 1, a software counter composed of a single eight-bit machine word can provide only 256 (0 through 255) distinct sequence number values. Once the software counter reaches its maximum value, it will roll over to zero the next time it is incremented. A rollover of the software counter will disrupt the logical time-stamp ordering as the event attached to time-stamp 110 will incorrectly appear to have occurred before the events attached to time-stamps 102-108.
To enable the provision of ever-increasing sequence numbers during the life span of a system, a software counter composed of more than one machine word may be used. For example, as shown in FIG. 2, by dedicating one eight-bit machine word as the base 216 (low order bits) and another machine word as the wrap 202 (high order bits), a software counter can significantly increase its range of valid sequence values and, therefore, substantially increase its effective life span.
It should be noted that FIGS. 1 and 2 depict eight-bit machine words for illustrative purposes only. These examples can easily be extended for computers that employ larger bit machine words, including but not limited to the sixteen or thirty-two bit machines that are commonly in use today. For example, if a thirty-two bit machine is used, a sixty-four bit software counter can be formed by using two thirty-two machine words.
Although utilizing sequence numbers that are multiple machine words long can eliminate the sequence number rollover obstacle in most systems, it has the side effect of introducing yet another problem. Specifically, machine instructions operate on one word at a time. Therefore, a sequence number stored in a software counter that comprises multiple machine words cannot be read or modified in an atomic operation. This gives rise to the possibility that some event may occur between accessing one word of the software counter and accessing another word of the software counter. Consequently, a sequence value obtained by one process may have been corrupted by another process seeking to procure a sequence number from the same software counter at the same time.
For example, if the software counter is comprised of multiple machine words BASE (low order bits) and WRAP (high order bits), two separate read instructions will be required to obtain the complete value. If after reading WRAP, but before reading BASE, another process modifies the software counter, the read instruction will return an incorrect value. Therefore, a process cannot be guaranteed that the returned sequence number is valid.
One technique to guarantee that the sequence number read from a multiple-word software counter will not be corrupted by concurrent processes is to serialize access to the software counter using a latch. Specifically, a latch is established for the software counter. Before a process can access the software counter, the process must obtain the latch. If another process already has the latch, the process must wait until the previous process releases the latch. By obtaining the latch before accessing the software counter, a process ensures that no other concurrently executing process will be concurrently accessing the software counter.
Latching the software counter ensures that the returned sequence number is valid and has not been corrupted by another process. However obtaining a latch can be particularly expensive if the latch is fault-tolerant as the system must retain enough information to be capable of automatically releasing the latch if the process holding the latch dies. Furthermore, allowing only one process at any given time access to a shared resource, such as the software counter, can create a significant bottleneck and, thus, significantly degrade the performance of a high concurrency system.
For example, if process A latches and acquires the shared resource, process B and process C must wait until the latch is released before they can acquire and access to the shared resource. This has the effect of serializing a concurrent system as processes are prohibited from executing until the shared resource is released and they are allowed to latch and access the shared resource themselves.
Additionally, further degradation of a concurrent system occurs when after acquiring a latch on the shared resource, process A is swapped out of memory to allow another process to execute. In this situation, all other processes requiring access to the sequence number must wait until the swapped-out process is rescheduled to execute and releases its latch on the shared sequence generator.
Requiring each process to wait until a latch can be obtained in order to read or modify a software counter has been proven to seriously degrade a database system's performance. Therefore, it is highly desirable for high concurrency systems to minimize the amount of time that a software counter is latched.

Latch-free sequence generation for high concurrency systems


Single molecules useful in vaccine compositions, and methods of making and using the same, are described.

The development of fully synthetic carbohydrate vaccines would be desirable. Protein conjugate vaccines have restrictions based on the innate immunogenicity of carrier proteins such as bovine serum albumin (BSA), and keyhole limpet hemocyanin (KLH), which can suppress the response against the associated carbohydrate antigen. A typical fully synthetic carbohydrate vaccine includes a carbohydrate antigen, T-helper cell epitope, and immunoadjuvant to boost the immune response. Modifications of this primary design have been investigated to achieve optimal immune response against the antigens.
The glycoconjugate patterns found on outer cell membrane of the normal epithelial cells and tumor epithelial cells are different. Thus, these aberrant carbohydrate components, also known as tumor associated carbohydrate antigens (TACAs), are promising as targets in cancer immunotherapy. TACAs, such as those depicted in FIGS. 1A-1B, can be used as carbohydrate epitopes in vaccine compositions. Different types of TACAs have been identified and classified according to their linkage to biomolecules. Lipid linked carbohydrates include GM2, GD2, GD3, Globo-H, and Lewisy, while glycoprotein antigens include Tn-, Thomsen-Friedenreich (TF-), and sialylated Tn (STn).
As an example, TACAs found on mucin 1 (MUC-1) have been exploited. MUC-1 is a tramsmembrane protein found in almost all epithelial tissues with heavy glycosylation. But in the case of cancer cells, truncated glycosylation, as well as premature sialylation, makes MUC-1 an attractive target. The extracellular portion of the MUC-1 contains a variable number (between 20 to 120) of tandem repeats with potential O-glycosylation sites (i.e, serines and threonines). Because of the truncated glycosylation in cancer cells, peptide sequences from variable numbers of tandem repeats (VNTRs) get exposed to the immune system, which usually are completely covered in normal cells. TACAs with VNTR domain have shown promising results in breaking the immune system's self-tolerance against MUC-1. The PDTRP (SEQ ID NO: 15) peptide has been identified as an immunodominant domain among VNTRs.
Though TACAs are promising targets in cancer immunotherapy, carbohydrate antigens are weak immunogens and give a T-cell independent immune response when used alone. These antigens bind to B cell receptors (BCR) because of their polymeric nature activating B cells. Since T cells are not involved in the process, the priming of activated B cells for isotype switching via T helper cells never happens, which causes production of low affinity IgM antibodies. This and other challenges remain Thus, there is a need in the art for new vaccine compositions.

Synthetic lipopeptide vaccines and immunotherapeutics


A method for generating alerts from a periodically sampled system is disclosed. The method includes maintaining a sampling window having a predefined number of most-recently collected samples. The method further includes calculating an alert value, the alert value representing a ratio of a first value to a total number of samples in the sampling window, the first value representing a total number of samples in the sampling window having parameters exceeding a predefined sample alert threshold. The method additionally includes generating a first alert if the alert value exceeds a predefined alert threshold.

Electronic monitoring is commonly employed to monitor the state of a system. From computer system performance to home security to automobile engines, electronic monitoring is increasingly employed to generate alerts if the monitored system fails to perform satisfactorily in some manner. Monitoring can be performed on a system-wide basis or on a component of the system. In the following disclosure, system monitoring is discussed although it should be understood that such discussion applies as well to monitoring an individual component since the difference is subjective. That is, a person may consider an object a system by itself, while another may consider the same object a component in a larger system.
One of the most common ways to continuously monitor a system is by periodic sampling. In periodic sampling, the state of the monitored system is sampled on a periodic schedule. In a typical monitoring situation, some predefined alert threshold is specified. If the value of the most recently obtained sample of data exceeds the predefined alert threshold, an alert is generated. If the most recently obtained sample falls below the threshold, no alert is generated.
This method of alert generation is, however, susceptible to transient conditions. For example, if the state of the monitored system swings rapidly above and below the predefined alert threshold every sampling period or every few sampling periods, alerts are alternately sent and suppressed. If the sampling period is relatively high, e.g., many times per second or per minute, the alert signal simply jitters on and off.

Hewlett-Packard Development Company, L.P.