A penetration-resistant modular security passway (20) includes a concrete vestibule (24), a doorframe (70), and a penetration-reactive security door (32). The vestibule (24) has a plurality of reinforcing members (36), a plurality of lifting lugs (26), and an embedded passive antipersonnel device (56). The doorframe (70) has hinge and strike jambs (108,110) attached to the reinforcing members (36). The hinge jamb (108) has a plurality of studs (124) and the strike jamb (110) a plurality of deadbolts (126) for protrusion into the door (32). The door (32) has a substruction (72), to which are affixed grates (86,92) and cladding (84,90). A girdle (100) is affixed to the cladding (84,90). Within a space (76) within the substruction (72), a metallic cable (78) is woven and a plurality of individually sealed tubes (96) containing a foaming agent (98) under pressure are suspended.

There exists a global need for the protection of sensitive structures from assault by an armed aggressor. Especially vulnerable to attack are nuclear power station containment and turbine buildings, armaments and munitions stores, weapons and biological research facilities, etc.
Weak points in the security of such structures are often entrances, especially entrances other than the primary entrances of the structures. Such non-primary entrances are traditionally protected by the use of a security door coupled with video cameras and other electronic devices. The outside area adjacent to the entrance is usually well illuminated and patrolled either physically or by video. To a trained aggressor, such protective measures are not an effective deterrent.
In the current world environment, security leaks are rampant. Data describing security systems and patrol schedules are often compromised. Additionally, an aggressor is likely to be well-trained, well-equipped, and acting for a "cause," i.e., willing to die to achieve a specific goal. There exists, therefore, a considerable problem in the protection of non-primary entrances to sensitive structures from assault by a skilled and determined aggressor in possession of suitable intelligence and materiel to achieve the aggressor's goal.
For example, were the destruction of a target at a specific facility to be the desired goal, an aggressor would have to assault the building housing the target. To accomplish this, an aggressor may utilize commando techniques to bypass perimeter security and gain access to the area adjacent to the building. Once in the appropriate area, the aggressor need only wait in concealment until patrolling guards have passed and are an appropriate distance away. The aggressor may then, in rapid succession, plant explosives to breach the security door, seek cover while the door is breached, gain ingress through the breached door, and use explosives to destroy the target. The first indication of assault may be the breaching of the door, with all subsequent actions occurring with sufficient rapidity to render the patrolling guards incapable of preventing the destruction of the target. The guards may, of course, be in a position to incapacitate the aggressor after the aggressor's goal has been achieved. Whether or not the aggressor can escape is often irrelevant.
As is exposed by the above assault scenario, a severe problem exists with conventional unguarded-door security methodology, especially since such "security" doors are often little more than glorified metal fire doors and are usually not proof against an explosive assault. The conventional solution is therefore to place a guard at the entrance in question. However, this in itself poses several problems.
A guard is subject to ennui, be the guard an individual or a team. It is virtually impossible to keep a guard alert indefinitely. After months or years without incident, an "if it hasn't happened, it won't happen" mentality can set into the subconscious and decrease the efficiency of the guard. In fact, the guard may suffer ennui to the point where there is effectively no guard at all, especially when there is a total absence of activity and boredom is at a maximum, as in the small hours of the morning. A traditional partial solution to this problem is an increase in random, unscheduled, and frequent simulated assaults and other training drills. Unfortunately, the use of such drills can in some ways actually decrease the efficiency of a guard, e.g., in the event of an actual assault, the guard may hesitate before initiating appropriate actions (i.e., actions requiring deadly force) on the assumption that "it's only another drill." Such a hesitancy may be all that is required to allow an aggressor to overcome the guard and gain ingress.
Additionally, in a well-planned and concerted assault, an aggressor may be able to overcome a guard without triggering an alarm. Such an attack is especially likely when the aggressor is in possession of suitable intelligence. Naturally, a guard consisting of an individual or a small team is far more likely to be overcome than one consisting of a large team, yet a large team is unlikely to be posted at an out-of-the-way location. Thus, the use of a guard is only partially effective at best.
Also, members of a guard may be subverted. This is more likely to occur with an individual or a small team than a large team, yet an individual or a small team is precisely the type of guard to be posted at a seldom-used structure entrance.
Another problem associated with guards is that guards are expensive. Wages, benefits, insurance, taxes, and training expenses can become a significant portion of a security budget.
An alternative method of providing security for secondary structure entrances is the use of a central guard. Such a guard is typically a large team maintained in a centralized location (a guard room). By being a large team, the guard suffers minimally from ennui. Also, by being a large team in a central location, the guard may be of sufficient strength to oppose an aggressor at any of a plurality of locations throughout the facility. However, the central location may be some distance away from secondary structure entrances, and a significant delay may occur before a central guard can detect and respond to an assault at a remote secondary structure entrance. Accordingly, it would be desirable if vestibular passways were provided for secondary structure entrances, and if such passways were constructed so as to delay ingress until a remotely located guard could arrive.
Several problems occur in the construction and implementation of vestibular security entrance passways. A passway to protect an existing structure entrance is conventionally constructed at the location it is to be used. This approach is often excessively expensive and insecure. An immediate and obvious difficulty lies in dealing with multiple venders to achieve construction. A first contractor, for example, may construct the security doors, a second contractor may construct the doorframes, a third contractor may construct the vestibule itself, and a fourth contractor may oversee the construction and integration of the components. Often, such multiple-vender scenarios lead to confusion and delays.
Quality control poses yet another problem. Security doors and passways desirably meet stringent quality-control requirements, e.g., material types and grades, explosion resistance, etc. Failing to meet specific requirements effectively compromises the entire vestibular entrance passway. With local contractors providing both materials and construction, it becomes very difficult to maintain quality control.
Additionally, the construction of such entrance passways is subject to active and passive sabotage. Sabotage occurs when actions are taken that compromise the integrity of the passway under construction. Active sabotage occurs when the individual(s) committing such actions intend to compromise passway integrity. Passive sabotage occurs when that passway integrity is compromised even though the individual(s) committing such action possess no such intent. In either case, sabotage is committed and the entrance passway fails to provide proper protection.
What is needed, therefore, is a vestibular entrance passway constructed off-site, where quality control and security can be maintained and where all standards can be met. This vestibular entrance passway should, when in position, severely inhibit ingress of an existing structure entrance by a highly trained, well-equipped aggressor, so as to delay ingress sufficiently to allow the arrival of armed guards from a central location.

Penetration-resistant security passway and door therefor


A capillary for a mass spectrometry system is described. The capillary comprises a channel and a tip, and at least one of the channel and the tip comprises a nanowire material.

Various analytical instruments can be used for analyzing proteins and other biomolecules. More recently, mass spectrometry has gained prominence because of its ability to handle a wide variety of biomolecules with high sensitivity and rapid throughput. A variety of ion sources have been developed for use in mass spectrometry. Many of these ion sources comprise some type of mechanism that produces charged species through spraying. One particular type of technique that is often used is Electrospray Ionization ("ESI"). One benefit of ESI is its ability to produce charged species from a wide variety of biomolecules such as proteins. Another benefit of ESI is that it can be readily used in conjunction with a wide variety of chemical separation techniques, such as High Performance Liquid Chromatography ("HPLC"). For example, ESI is often used in conjunction with HPLC for identifying proteins.
Typically, ESI produces a spray of ions in a gaseous phase from a sample stream that is initially in a liquid phase. For a conventional ESI mass spectrometry system, a sample stream is pumped through a metal capillary, while a relatively high electric field is applied between a tip of the metal capillary and an electrode that is positioned adjacent to the tip of the metal capillary. As the sample stream exits the tip of the metal capillary, surface charges are produced in the sample stream, thus pulling the sample stream towards the electrode. As the sample stream enters the high electric field, a combined electro-hydrodynamic force on the sample stream is balanced by its surface tension, thus producing a "Taylor cone." Typically, the Taylor cone has a base positioned near the tip of the metal capillary and extends up to a certain distance away from the tip of the metal capillary, beyond which a spray of droplets is produced. As these droplets move towards the electrode, coulombic repulsive forces and desolvation lead to the formation of a spray of ions in a gaseous phase.
During operation of a conventional ESI mass spectrometry system, characteristics of a Taylor cone can affect characteristics of a spray of ions, which, in turn, can affect results of mass spectrometric analysis. Accordingly, it is desirable to produce Taylor cones with certain reproducible characteristics, such that results of mass spectrometric analysis have a desired level of accuracy and reproducibility.

Nanowire capillaries for mass spectrometry


A method for fabricating a liquid crystal display device includes: forming a pixel electrode on a substrate; forming a first conductive layer on the pixel electrode; forming a first photoresist pattern on the conductive layer; forming a source electrode forming portion, a channel forming portion and a pixel electrode forming portion using the first photoresist pattern as a mask; forming a semiconductor layer over an entire surface of the substrate; forming an insulating layer on the semiconductor layer; forming a second conductive layer on the insulating layer; forming a second photoresist pattern on the second conductive layer; forming an active layer using the second photoresist pattern; and forming a gate electrode on the active layer.

1. Field of the Invention
The present invention relates to a method for fabricating a liquid crystal display, and more particularly, to a method for fabricating a liquid crystal display (LCD) device using two masks.
2. Description of the Related Art
As interest in image display devices and demand for portable information device increases, a thin film type Flat Panel Display (FPD) devices have been developed and replaced traditional Cathode Ray Tubes (CRT) type display devices. In particular, a liquid crystal display (LCD) device having the characteristic of an optical anisotropy has replaced the CRT. Further, the liquid crystal display device has been used in notebook computers, desktop monitors, or the like because it has an excellent resolution, color rendering capability and picture quality.
A liquid crystal display device includes a color filter substrate, which is a first substrate, an array substrate, which is a second substrate, and a liquid crystal material formed between the two substrates. A thin film transistor, which uses amorphous silicon or polycrystalline silicon as a channel layer, is used as a switching device of the liquid crystal display device. A process for fabricating the liquid crystal display device usually requires a plurality of photo-mask processes in fabricating the array substrate including the thin film transistor.
FIG. 1 is a plan view showing a unit pixel of an array substrate of a liquid crystal display device of the related art. In a typical liquid crystal display device, the 'N' number of gate lines and the 'M' number of data lines cross each other, forming the 'N x M' number of pixels. For the purpose of simplicity, only one pixel is presented in the FIG. 1. As shown in FIG. 1, the array substrate 10 includes: a pixel electrode 18 formed at a pixel region; gate lines 16 and data lines 17 disposed vertically and horizontally on the substrate 10; and a thin film transistor used as a switching device, which is formed at a region adjacent to where the gates lines 16 and the data lines 17 cross each other.
The thin film transistor includes: a gate electrode 21 connected to the gate line 16; a source electrode 22 connected to the data line 17; and a drain electrode 23 connected to the pixel electrode 18. Also, the thin film transistor includes: a first insulating layer (not shown) and a second insulating layer (not shown) for insulating the gate electrode 21 and source/drain electrodes 22 and 23; and an active layer 24 for forming a conductive channel between the source electrode 22 and the drain electrode 23 by a gate voltage supplied to the gate electrode 21. The source electrode 22 is electrically connected to a source region of the active layer 24 and the drain electrode 23 is electrically connected to a drain region of the active layer 24 through first contact holes 40a formed in the first and second insulating layers. Since a third insulating layer (not shown) has a second contact hole 40b exposing the drain electrode 23, the drain electrode 23 and the pixel electrode 18 are electrically connected to each other through the second contact hole 40b.
FIGS. 2A to 2G are cross-sectional views along the line I-I of the liquid crystal display device shown in FIG. 1 showing fabrication processes according to the related art. As shown in FIG. 2A, the active layer 24 of polysilcon is formed on a transparent substrate 10, such as a glass, by using a photolithography process.
Next, as shown in FIG. 2B, a first insulating layer 15a is deposited over the entire surface of the substrate 10 on which the active layer 24 is formed and a conductive metal layer 30 are deposited on the first insulating layer 15a.
Next, as shown in FIG. 2C, a gate electrode 21 is formed on the active layer 24 with the first insulating layer 15a interposed therebetween by patterning the conductive metal layer 30 using a photolithography process. Thereafter, source/drain regions 24S and 24D are formed by injecting N+ or P+ high density impurity ions into side regions of the active layer 24 using the gate electrode 21 as a mask. The source/drain regions 24S and 24D are formed for ohmic contacts of the active layer to the source/drain electrodes.
Next, as shown in FIG. 2D, after a second insulating layer 15b as an interlayer is deposited over the entire surface of the substrate 10 on which the gate electrode 21 is formed, the first contact holes 40a exposing the source/drain regions 24S and 24D are formed through the first insulating layer 15a and the second insulating layer 15b through photolithography.
Thereafter, as shown in FIG. 2E, after a conductive metal is deposited over the entire surface of the substrate 10, the source electrode 22 connected to the source region 24a and the drain electrode 23 connected to the drain region 24b are formed through the first contact holes 40a. At this time, a part of the conductive metal constructing the source electrode 22 is extended to be connected to the data line 17.
Next, as shown in FIG. 2F, a third insulating layer 15c, an organic insulating layer, such as Acryl, is deposited over the entire surface of the substrate 10, and the second contact hole 40b is formed to expose the drain electrode 23 by photolithography.
Finally, as shown in FIG. 2G, transparent conductive materials, such as Indium Tin Oxide (ITO), are deposited over the entire surface of the substrate 10 and into the second contact hole 40b. The pixel electrode 18 is connected to the drain electrode 23 through the second contact hole 40b and patterned by using photolithography on the transparent conductive materials. More specifically, the photolithography forms an active pattern, a gate electrode, a first contact hole, source/drain electrodes, a second contact hole and a pixel electrode, respectively, when fabricating a liquid crystal display device including a polysilicon thin film transistor.
Photolithography refers to a series of processes in which desired patterns are formed by transcribing a pattern drawn on a mask to a substrate on which a thin film is deposited, and includes a plurality of processes, such as photoresist solution application, exposure, development, or the like. As a result, a plurality of photolithography processes lower production yield and are prone to cause defects in the thin film transistor. Since a mask used for photolithography is very expensive, if many number of masks are used to form LCD device, ion costs for the liquid crystal display device are also increased. Thus, productivity can be increased, if the usual number of photo-mask steps is decreased.

Method for fabricating liquid crystal display device using two masks


The present invention relates to a process for preparing a printed can be draw-forming or draw-redraw-forming a preliminarily printed metal blank or laminate. By forming an original plate for printing by an image processing by a computer, a print image faithful to the original image can be manifested on the side wall portion of the can, and formation of an undesirable stripe pattern can be prevented. Furthermore, a print image excellent in the linearity can be displayed without an error on the draw-formed can in due consideration of the anisotropy owing to the plastic flow of the blank.

Draw-forming of a surface-treated steel sheet such as a tinplate or tin-free steel sheet or a metal sheet such as an aluminum sheet is widely adopted for the manufacture of a so-called seamless can (two-piece can) and a metal cap. Coating or printing of individual formed bodies after the forming operation requires a complicated operation, and therefore, coating or printing of a flat blank before the draw-forming is desirable.
In draw-forming, a flat metal blank undergoes the plastic flow and is formed into a cup-shaped body. When the plastic flow of the portion of the flat blank, that will constitute the circumferential side wall portion of the formed body, is taken into consideration, it is confirmed that in this portion, elongation is caused in the direction corresponding to the height direction of the formed body.
In the preliminary printing of a flat blank for draw-forming, in view of the above-mentioned plastic flow of the blank, it is necessary that an original which is rectangular in the developed state should be converted to an annular printing plate. As means for effecting this conversion, there are known a hand-writing method, an optical conversion method and a digital conversion method proposed by us (Japanese Unexamined Patent Publication No. 61-267763 and Japanese Unexamined Patent Publication No. 61-267053).
However, in a can obtained by draw-forming a preliminarily printed metal blank, a striped pattern not found in the original print image is often formed at the upper part of the side wall portion, and this is especially conspicuous in a deep-draw-formed can or a can in which the thickness of the side wall portion is reduced by bending-rebending deformation.
As the result of the research made by us, it was found that in the draw forming of a preliminarily printed metal print, at the upper part of the side wall portion, dots become continuous owing to the compression flow of the blank in the circumferential direction and spaces between dots in the height direction increase owing to the elongation flow of the blank in the height direction, and this deformation of the dots tends to result in formation of a striped pattern.
Furthermore, the above-mentioned prior art techniques are defective in that the object is limited to an ordinary draw-formed can.
In the draw-redraw forming of a covered metal sheet, there is known a method in which the metal sheet is draw-formed into a deep-draw-formed cup by a curvature corner portion of a redrawing die and the side wall portion is subjected to the bending-rebending deformation to reduce the thickness. However, in the production of this thickness-reduced draw-formed can, there is not known a method in which the metal blank used is preliminarily printed and a print image faithful to the original image is manifested.
According to the above-mentioned hand-writing method, a rectangular transparent original ruled in squares is wound around the circumferential side wall portion of the draw-formed body, areas corresponding to the original image are painted by hand writing on the annular developed plane having squares correspondig to those of the ruled original to prepare a printing plate for a sheet-shaped blank. However, a high skill is necessary for the preparation of this printing plate and a large cost and a long time are required. Moreover, the print image practically reproduced on the circumferential side wall portion of the draw-formed body is still insufficient in the precision and the like.
The technique of forming a printing plate by optically developing a rectangular original annularly has already been proposed. For example, Japanese Examined Patent Publication No. 45-11388 discloses a method in which a rectangular original is photographed so that the height direction is shortened, the obtained photo is wound around a mandrel and the photo is photographed again through a frustoconical mirror arranged around the mandrel to obtain a printing plate having an annularly developed image, and Japanese Examined Patent Publication No. 48-23455 discloses a method in which a frustoconical prism having at the center a hole having an inner diameter almost equal to the outer diameter of the can is arranged, a rectangular original is located on the inner surface of the hole and this original image is photographed by a camera through the above-mentioned prism and a correcting lens to form a plate having an annular plane.
In these methods, however, troublesome operations and particular optical devices are necessary, and because of the abberation or the like of the optical system, it is difficult to reproduce a fine dot pattern at a high precision. Moreover, every time the original for the draw-formed body is changed, the troublesome conversion operation should be carried out for forming a plate.
In each of metal blanks for cans, the thickness is reduced by a high rolling operation, and an anisotropy is produced in the plastic flow of the blank at the draw-forming by an influence of this rolling. Accordingly, turbulence of a print image is readily caused in the side wall portion of the obtained draw-formed can, especially at the upper part of the side wall portion, and the precision or linearity of the image is often degraded.

Process for the preparation of a draw-formed printed can


A user of a mobile communications device may access services in a target domain using a source domain identity that is used to access services in a source domain. To enable such a use of the source domain identity in the target domain, the source domain identity may first be enrolled in the target domain. The enrollment may be facilitated by an enrollment entity at the target domain, such as a gateway or an OpenID server for example. The enrollment entity may establish a secure channel with the user's device for enabling enrollment of the source domain identity. Once enrolled, the source domain identity may be used for authentication of the user in the target domain. Enrollment of the source domain identity and/or authentication of the user based on the enrolled source domain identity may be implemented using a local OpenID provider (OP) residing on the user's device.

The use of mobile communications devices enables users to access a number of services as they are moving from one location to another. For example, a user may come into proximity of various wireless networks or domains when moving locations. Each network may offer a number of services to the user. In order to access these services, the user may have to login to the network using a registered user identity. This registered user identity may be used by the service provider to authenticate the user to allow the user to access its services.
If the user wants to access services in another network or domain, the user may be forced to perform another registration. If the user attempts to use the user identity that has been registered in another domain, they may receive an error message. Thus, the user may be forced to register separately with each network in which the user wishes to access services from a service provider. This may require the user to remember many different registered identities. Alternatively, the user may register the same, or similar, identity in each network to avoid having to remember each of the different registered identities. This may present security concerns as an attacker may acquire the identity for one network and, as a result, have access to other networks in which the user has used this same identity.
Some service providers may implement OpenID to address some of these concerns. However, even in OpenID a client may belong to a domain which is defined by its discovery and trust relationships with the domain entities. The client may not be able to login with a relying party (RP) that belongs to another identity domain, because this RP does not have a trust relationship with the authentication entities in the source domain, and thus may not trust authentication from the client.

Client and server group SSO with local openID


An orchard heat exchanger comprises an engine-driven shaft having an air propeller on each end. The assembly is enclosed in an open-ended horizontal cylindrical shroud, which has a large converging-diverging air inlet at the top, and is trailer mounted. The orchard heat exchanger has the capability of being elevated to treetop level. In a first embodiment, the engine-propeller-shroud assembly may be rotated in a horizontal plane. In a second embodiment, there is no horizontal rotational capability, but the cylindrical shroud is fitted with directional louvers at each end.

In orchard areas, in the Spring of the year, temperature inversions are common, and can cause damage to the fruit buds and blossoms. During a temperature inversion, the air temperature at the level of the trees is colder than the air temperature above the orchard. In some orchard areas where there is no air drainage, the still air can become particularly cold.
Various methods are used to protect the buds and blossoms against freezing. A fine water spray system can assure, up to a point, that the buds and blossoms remain at the freezing temperature of water, as the water is continually at the latent heat of fusion. A great many orchardists use wind machines, which are large motor-driven propellers mounted on towers above treetop level. Of course, ground-level heaters are also used.
Ideally, it is preferable to pull the warm air down from above the treetop level and distribute it at or below the leafy portions of the trees.


A fuser cleaning apparatus and method of operating a fuser cleaning apparatus for use with an image forming device. Heat is efficiently transferred to a guide member of a fuser, thereby allowing for relatively easy performance of a cleaning operation of the fuser, since a heating roller of the fuser is heated by a heater while the heating roller is not in motion. It is also possible to prevent melted toner remnants from contaminating the heating roller since a sheet of paper which has waited at an entrance of the fuser is conveyed and passed between the heating and pressure rollers of the fuser after the heating roller is heated while it is not in motion.

1. Field of the Invention
Aspects of the present invention relate to a fuser cleaning apparatus and a method of operating a fuser cleaning apparatus for use with an image forming device, in which a contaminated fuser of the image forming device is cleaned by a heating of a heating roller of the fuser while the heating roller is not in motion.
2. Description of the Related Art
In an electro-photographic image forming device, a latent image is formed on a photosensitive drum to which toner is adhered. The toner is developed into a visible image using developer and the visible toner image is then transferred to a print medium, such as paper or a transparency. The image transferred to the print medium is fixed to the print medium by passing the print medium through a fuser. Once the print medium has passed through the fuser, the print medium is discharged from the image forming apparatus.
The fuser applies heat and pressure to the print medium to fix the image to the print medium. To this end, the fuser includes a heating roller to apply heat to the print medium and a pressure roller to apply pressure to the print medium. The heating roller and the pressure roller are provided along a conveyance path of the print medium.
As a result, it is frequently necessary to clean a fuser that becomes contaminated with toner. According to a conventional method of cleaning a fuser, a fusing temperature of the fuser is set to a high preset temperature in a cleaning mode via a heating of the heating roller while rotating the heating and pressure rollers. When the fusing temperature reaches the preset temperature, the medium (i.e., a sheet of paper) is picked up and passed between the heating and pressure rollers to remove melted toner.
The fuser further includes a guide member, which is referred to as a claw, to smoothly discharge media while preventing them from being wound around the photosensitive drum. As the number of sheets of media printed on increases, an increasing amount of toner that attaches to the guide member ends up being fixed to the guide member due to the fusing temperature increases during fusing processes. However, according to the conventional cleaning method, melting toner contaminants on the guide member is difficult since the cleaning operation is performed while the heating roller rotates. Rather, toner contaminants on the heating and pressure rollers may be added to toner contaminants on the guide member.
Thus, the conventional cleaning method is not effective to clean contaminants on the guide member. If the contaminants fixed to the guide member scratch a medium to be discharged, undesired vertical black lines may be printed on the medium and the medium may also be jammed.

Fuser cleaning apparatus and method of operating a fuser cleaning device for use with an image forming device


A friction clutch for arrangement in the power train of a motor vehicle. The friction clutch includes a flywheel mass arrangement to be fastened to an input shaft rotating about an axis of rotation. A pressure plate unit with a clutch housing is held at the flywheel mass arrangement. A contact-pressure plate is guided so as to be axially displaceable relative to the clutch housing and the flywheel mass arrangement. A clutch spring arrangement axially spring loads the contact-pressure plate toward the flywheel mass arrangement. A clutch disk with friction facings projects between, on the one side, friction surfaces of the flywheel mass arrangement which are located axially opposite one another and, on the other side, the contact-pressure plate. The flywheel mass arrangement and the contact-pressure plate are coupled with one another in a torsionally elastic manner with reference to the axis of rotation in order to limit the peak torque transmitted through the friction clutch. For this purpose, the flywheel mass arrangement is preferably constructed as a two-mass flywheel.

1. Field of the Invention
The invention is directed to a friction clutch to be arranged in the power train of a motor vehicle.
2. Description of the Prior Art
A conventional friction clutch to be arranged in the power train of a motor vehicle includes a flywheel which is rotatable about an axis of rotation. The flywheel can be coupled to one end of a crankshaft of an internal combustion engine and has a friction surface facing away axially from the crankshaft. A friction facing of a clutch disk connectable with a transmission input shaft is connected in a frictional engagement with the friction surface of the flywheel when the friction clutch is engaged. A pressure plate unit is provided in order to apply the contact pressure force needed for the frictional engagement between the friction facing of the clutch disk and the friction surface of the flywheel. The pressure plate unit comprises a clutch housing which is rigidly connected with the flywheel radially outside the friction facing and extends radially inward so as to partially surround the clutch disk. A contact-pressure plate is supported axially against the clutch housing via a clutch spring. The contact-pressure plate is provided with a friction surface which is located opposite the friction surface of the flywheel facing the crankshaft and communicates with a friction facing of the clutch disk in a frictional connection when the friction clutch is engaged. Frictional forces of roughly equal magnitudes are transmitted to the clutch disk by the friction surface of the contact-pressure plate and the friction surface of the flywheel given an identical construction of these two friction surfaces. Torque is accordingly transmitted from the crankshaft to the clutch disk connected with the transmission input shaft via two separate torque transmission paths. The first torque transmission path extends from the flywheel, via the friction surface of the flywheel, directly to the clutch disk. The second torque transmission path extends from the flywheel to the clutch disk via the clutch housing, clutch spring, contact-pressure plate and friction surface provided at the latter. Torques of approximately equal magnitude are transmitted via both torque transmission paths.
In addition to the torques to be transmitted by the friction clutch during normal driving and shifting operation, peak torques which are generated, for example, by incorrect operation such as engaging the clutch in a jerking manner, are also transmitted to the clutch disk by the frictional engagement between the flywheel and clutch disk. In this connection, there exists the risk that these peak torques can damage components of the friction clutch itself, as well as components of the gearbox or transmission. In order to withstand these peak torques, which only occur occasionally, these components must exhibit a mechanical strength and robustness beyond that required for normal operation.


An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. The fixer inlet discharging into a vertically oriented conduit located within the vessel, which contains iron therein and defines a gravity flow path for flow of the fixer within the vessel from the inlet to the bottom of the vessel. A layer of steel wool is positioned on the bottom of the vessel in the flow path of the fixer. Baffles inside the chamber promote mixing of the developer and fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber. A wash water inlet tube is aligned with an open ended vessel that surrounds the discharge outlet to dilute the mixed and neutralized developer and fixer.

This invention pertains to waste processing, and more particularly to apparatus for treating and disposing of spent photographic fixer and developer chemicals and removing silver therefrom.
The present invention is a further development of the effluent precipitation and neutralization chamber described in Woog, U.S. Pat. Nos. 4,608,177 and 5,132,022. In these apparatus of these patents, spent photographic fixer and spent photographic developer are mixed together in a closed chamber. To assure proper mixing of the spent fixer and developer, the fluid flow paths within the chambers included baffles and materials such as plastic ribbons that caused the fluids to flow in a tortuous path. The spent fixer, which is normally acidic in nature, having a pH of about 4.5, is neutralized by the alkaline developer, which normally has a pH of about 10.5. As a result, iron in the fixer in the form of ferrous oxide is precipitated as fine particles, and a relatively neutral and clear liquid is discharged from the chamber to a drain. The iron precipitate is periodically cleaned from the chamber for proper disposal.
This invention relates to improvements over the apparatus set forth above and to solutions to the problems raised or not solved thereby.

Effluent neutralization process and chamber


A method of patterning layered structure oxide thin films involving placing the layered structure thin film (with or without a mask) laid on a substrate into a chamber which is partially filled with CHC1FCF.sub.3 gas and producing a glow discharge to cause the etching of the thin film ferroelectric material. The method provides high etch rates, good etch anisotropy and good etch uniformity. For example, for SBT and SBN thin films, the etch process provides etch rates in the range of 2.5 to 17.5 nm/min depending on the etch conditions and minimal etch residues at the end of the etch process is removed easily by low temperature (250.degree. C.) baking. Also, the method provides good etch selectivity in the films and minimal surface damage.

Ferroelectric materials are characterized primarily by a spontaneous polarization, the orientation of which can be reversed by an electric field. In addition, these materials also display unique dielectric, pyroelectric, piezoelectric and electro-optic properties that are utilized for a variety of applications such as capacitors, dielectric resonators, heat sensors, transducers, actuators, nonvolatile memories, optical waveguides and displays. For device applications, however, it is useful to fabricate ferroelectric materials in the form of thin films so as to exploit these properties and the design flexibility of thin film geometries. Ferroelectric thin films can be deposited using different techniques such as physical vapor deposition, chemical vapor deposition and chemical solution processes including sol-gel and metalorganic decomposition.
Although ferroelectric materials have found a number of applications in several demonstrative ferroelectric devices, the primary impetus of recent activity in ferroelectric thin films is the large demand for commercial nonvolatile memories. The polarization in a ferroelectric shows hysteresis with the applied electric field; at zero field, there are two equally stable states of polarization, + or -P.sub.r, as shown in FIG. 1. This type of behavior enables a binary state device in the form of a ferroelectric capacitor (metal-ferroelectric-metal) that can be reversed electrically. Either of these two states could be encoded as `1` or `0` in a computer memory and since no external field (power) is required to maintain the state of the device, it can be considered a nonvolatile memory device. To switch the state of the device, a threshold field (coercive field) greater than + or -E.sub.c is required. In order to reduce the required applied voltage, the ferroelectric materials need to be processed in the form of thin films. Integration of ferroelectric thin film capacitors into the existing VLSI results in a true nonvolatile random access memory device (see J. F. Scott and C. A. Paz de Araujo, Science, 246, (1989), 1400-1405). In addition to the nonvolatility , ferroelectric random access memories (FRAMS) also offer high switching speeds, low operating voltage (<5 V), wide operating temperature range and high radiation hardness. Furthermore, the ferroelectric thin films, electrodes and passivation layers can be deposited in separate small facilities thereby obviating the need for any changes in the existing on-line Si or GaAs VLSI production. In principle, FRAMS could eventually replace static RAMS (SRAMs) in the cache memory, dynamic RAMs (DRAMs) in the main system memory and electrical erasable programmable read only memories (EEPROMs) in look-up tables.
Although ferroelectric thin films offer great potential for nonvolatile RAMs, commercial usage has been hindered largely by serious degradation problems such as fatigue, leakage current and aging that affect the lifetime of ferroelectric devices. A common source for these degradation properties in oxide ferroelectrics is the presence of defects such as oxygen vacancies in the materials. Considering the problem of fatigue, ferroelectrics are noted to lose some of their polarization as the polarization is reversed. This is known as fatigue degradation and is one of the prime obstacles to forming high quality ferroelectric thin films. The hysteresis loop "shrinks" on account of fatigue and finally after a large number of cycles it is difficult to distinguish between a `1` and a `0` in the memory device, thus rendering it ineffective. Fatigue (see I. K. Yoo and S. B. Desu, Mat. Sci. and Eng., B13, (1992), 319; I. K. Yoo and S. B. Desu, Phys. Stat. Sol., a133, (1992), 565; I. K. Yoo and S. B. Desu, J. Int. Mat. Sys., 4, (1993), 490; S. B. Desu and I. K. Yoo, J. Electrochem. Soc., 140, (1993), L133) occurs because of both the relative movement of oxygen vacancies and their entrapment at the electrode/ferroelectric interface (and/or at the grain boundaries and domain boundaries). These defects are created during the processing of ferroelectric films (with the desired ferroelectric phase). Under an externally applied a.c. field (required to cause polarization reversal), the oxygen vacancies have a tendency to move towards the electrode/ferroelectric interface as a result of the instability of the interface. Eventually, these defects are entrapped at the interface and cause structural damage. This results in a loss of polarization in the material.
There are two possible solutions to overcome fatigue and other degradation problems. The first is to reduce the tendency for entrapment by changing the nature of the electrode/ferroelectric interface. Multilayer electrode structures using ceramic electrodes such as RuO.sub.2 which minimize oxygen vacancy entrapment have been used to minimize fatigue problems in oxide ferroelectrics (see U.S. patent application Ser. No. 08/104,861 filed Aug. 8, 1993). The second solution involves the control of defect density. The extrinsic point defect concentration may be minimized by reduction of impurity concentration or through compensation of impurities. La and Nb doping are known to reduce the fatigue rate of PZT thin films on Pt electrodes by compensating for the vacancies (see S. B. Desu, D. P. Vijay and I. K. Yoo, Mat. Res. Soc. Symp., 335, (1994), 53). The strategies for minimizing the intrinsic defect concentration may include choosing compounds with inherently high defect formation energies or choosing compounds that have no volatile components in their sublattice exhibiting ferroelectric properties. Thus, another alternative to overcome fatigue and other degradation problems is to use a ferroelectric compound that does not contain any volatile components in its sublattice that exhibits ferroelectric properties. This criterion is satisfied by many of the known layered structure ferroelectric oxides.
In the layer-structure family, a large number of compounds of the general form (Bi.sub.2 O.sub.2).sup.2+ (M.sub.n-1 R.sub.n O.sub.3n+1).sup.2-, where M=Ba, Pb, Sr, Bi, K or Na, n=2, 4 or 5 and R=Ti, Nb or Ta, are known to be ferroelectric (see E. C. SubbaRao, J. Phys. Chem. Solids, 23, (1962), 665; B. Aurivillius, Arkiv Kemi 154!, (1949), 463; E. C. SubbaRao, J. Chem. Phys., 34 2!, (1961), 695; G. A. Smolenski, V. A. Isupov and A. I. Agranovskaya, Fiz Tverdogo Tela, 33!, (1961), 895). These compounds have a pseudo-tetragonal symmetry and the structure is comprised of stacking of n perovskite-like units of nominal composition MRO.sub.3 between Bi.sub.2 O.sub.2 layers along the pseudo-tetragonal c-axis. A large number of these compounds do not contain any volatile components in their sublattice that exhibit spontaneous polarization. The tendency for formation of defects such as oxygen vacancies and thereby the degradation problems such as fatigue may thus be reduced.
Novel deposition processes for fabrication of thin film layer structure oxides have been disclosed earlier. However, for ferroelectric device applications, it is also necessary to develop a patterning technology for these devices. Memory devices such as dynamic and random access memories have decreased in size over the last two decades. As the capacity of memory cells has increased and the size has decreased, the design of the cells has become increasingly complex in order to preserve sufficient electrical capacitance to hold the electrical charge representing the data. To produce these complex shaped cells, it is first necessary to transfer the required geometric shape from a mask to the surface of the film to be patterned. This is accomplished by the process of lithography. In a typical lithographic process, a photosensitive polymer (photoresist) film is coated on top of the thin film layers (deposited on a substrate) to be patterned, dried and then exposed with the appropriate geometrical patterns through a photomask to ultraviolet or other radiation. The substrate holding the film layers is then soaked in a solution that develops the images in the photosensitive material. Depending on the type of the polymer used, either exposed or non-exposed areas of the polymer film are removed in the developing process. To produce circuit features, these resist patterns must be transferred into layers comprising the device. A preferred method of transferring the patterns is to selectively remove the unmasked portions of the layers comprising the device. This process is generally known as etching (see S. M. Sze, "VLSI Technology", McGraw-Hill Co., 1983).
Etching techniques can be broadly classified into wet and dry etching processes. Selectivity for wet etching is usally good, most of the time much better than dry etching. The main disadvantage of wet etching is poor line width control and limited resolution because it is essentially an isotropic etch resulting in an undercut of the mask equal to the thickness of the layer to be etched. Wet chemical etching processes are not popular in applications where complex patterning is required because of the low etch rates, poor etch anisotropy, poor uniformity and the poor selectivity that they provide. On the other hand, dry etching techniques are highly suitable for device applications because this patterning technology provide rapid rates of etching of the materials, high resolution so that it can be used in complex configurations, good selectivity so that the underlying materials are not etched when not required, and also provide uniform etching. Dry etching techniques comprise a whole class of etching processes that use plasmas in the form of low-pressure gas discharges to accomplish the etching process. Broadly, this method is comprised of techniques such as sputter etching, ion milling, plasma etching, reactive ion etching and reactive ion beam etching.
In the past, perovskite type ferroelectrics such as PZT and PLT have been etched by techniques such as laser-induced sputtering (see M. Eyett, D. Bauerie, W. Wersing and H. Thomann, J. Appl. Phys, 62, 1987, 1511), chemical wet etching (see H. T. Chung and H. G. Kim, Ferroelectrics, 76, 1987) and reactive ion etching (see M. R. Poor, A. M. Hurt, C. B. Fledermann and A. U. Wu, Mat. Res. Soc. Symp. Proc., 200, 1990). However, it is believed that the etching of layer structure oxides ferroelectrics has never been reported before. This may be because of an inability to identify an etching gas for the plasma that can meet the stringent conditions required for device applications. In the present invention, an etch gas is identified, CHC1FCF.sub.3, for dry etching of ferroelectric layered structure oxide thin films.

Virginia Tech Intellectual Properties, Inc.


A method, system, and/or apparatus for automatically monitoring for possible infection or other physical health concerns, such as from Covid-19. The method or implementing software application uses or relies upon location information available on the mobile device from any source, such as cell phone usage and/or other device applications. The method and system automatically uses and/or learns user location and activity patterns and determines and infection risk or illness-based deviation that can be communicated as a warning to community members.

The current Covid-19 pandemic has magnified a need for monitoring methods. Contract tracing relies on a person to self-identify as infected, and suffers from concerns of information leaks. Testing and treatment can be difficult due to shortages, delays, etc.
Prevention is better than treatment. There is a need for passive monitoring based systems and methods that indicate likelihood of viral and/or bacterial exposure, such as due to contact with a specific individual.
Social media systems have permeated daily life. Information is collected, organized, and disseminated worldwide via informational collection and dissemination, micro-blogging and blogging services. Other social media are mobile and positional in nature and can be referred to as Mobile Positional Social Media (MPSM). As these systems focus on locations, mobile device implementations permeate the space. That said, however, while MPSM implementations are targeted to primarily execute on mobile devices, such as but not limited to smart-phones (e.g., Apple's iPhone, Google's Android), tablets (e.g., Apple's iPad, HP TouchPad), and laptop computers, they often support implementations for non-mobile environments such as but not limited to desktops and workstations, and large scale compute farms and cloud computing servers.
One limitation of MPSM systems is their reliance on global positioning systems (GPS). The use of GPS devices does typically simplify location tracking implementation; however, this comes at a significant energy cost. Since a significant portion of MPSM systems usage is via mobile devices, reducing energy consumption is critical.
Another limitation of current MPSM systems, similar to contact tracing, is their reliance on active users identifying their location and/or their activity at the location. Another limitation of current MPSM systems is the limited modes of informational guidance provided to the user. For example, no reminders or instructional commenting is provided. That is, users are not reminded of activities that fit their given location and context in a push manner; rather, user inquiry of locally available options is needed. Ideally, given location and context users are proactively pushed information that is immediately relevant to them. Additionally, activities that are nearby to their current location or will become available can likewise be identified.
The use of smartphone technology for medical applications is increasing. In August 2014, the Food and Drug Administration (FDA) cleared a smartphone device, AliveCor, that detects atrial fibrillation, a potential warning sign for heart failure and stroke. Additionally, Apple Corporation, in support of medical smartphone technology, recently developed an open-source tool kit to aid in the authoring of medical research applications. Also known in the art is the use of activity and trend detection using smartphone technology for medical applications. Recently, an Android based application called StudentLife was introduced at Dartmouth College. This application monitors smartphone use (e.g., text messaging, e-mail traffic, etc.) as well as additional activity (e.g., mobility and sleep patterns) to infer state of being. Automatic sensed, as well as interactive user probing, data were collected to determine potential stress.
There is thus a continuing need for and interest in improved mobile device-based systems and applications for medical applications, and particularly for infectious disease control and monitoring.

This patent is subject to a terminal disclaimer.

Infection risk and illness assessment method


Systems and methods for creating loopback packets for transmission through a section of a network for the purpose of testing the operability of links and nodes in this section of the network are provided. A method, according to one implementation, includes a step of obtaining information, by a Network Element (NE), about the topology of the network related to at least the nodes in direct communication with a peer node. The method also includes a step of generating one or more loopback packets, where each loopback packet includes at least a header having a path list including one or more nodes of the plurality of nodes in the network. Each path list defines an order of nodes through which the respective loopback packet is to be transmitted.

Generally, Bidirectional Forwarding Detection (BFD) is a protocol that is used for detecting faults in a communications network. BFD is normally implemented to discover faults between a pair of nodes (e.g., routers, switches, etc.) connected by a link (e.g., optical fiber link). If a first node detects a fault with respect to communications with a second node, the first node usually assumes that the fault is within the second node itself. Protection paths can thereby be arranged to avoid this second node. However, BFD does not allow the first node to determine if the fault is a "node failure" (i.e., a failure at the second node) or if it is a "link failure" in the link connecting the first and second nodes.
In the case of multi-hop BFD or Seamless BFD (S-BFD), there is a need to detect the operability or liveness of a node in a reliable manner. BFD packets should follow the same set of nodes/links in both directions. Even if the forward Segment Identifier (SID) stack may be a Topology Independent—Loop-Free Alternate (TI-LFA) backup path computed by a Point of Local Repair (PLR) device, operators need to derive the reverse SID stack from the forward path for BFD or S-BFD to use. Besides, a TI-LFA backup path can change due to topological change. Reverse SID stack must be derived again whenever TI-LFA backup paths change. This adds to operational complexity.
Also, BFD requires more processing of configurations (e.g., double-sided) on the PLR as well as all of its neighbors. Therefore, there is a need in the field of fault detection in a communications network to simplify the configuring processes of the multiple nodes whereby the PLR, by itself, can configure a testing strategy that enable the PLR to determine if a fault is a node fault or a link fault, regardless of the number of protected links and nodes in a system.

Creating a packet with a loopback label stack to detect network link/node failures


An electronic fuse (e-fuse) module may be formed in an integrated circuit device. The e-fuse module may include a pair of metal e-fuse terminals (e.g., copper terminals) and an e-fuse element formed directly on the metal e-fuse terminals to define a conductive path between the pair of metal e-fuse terminals through the e-fuse element. The metal e-fuse terminals may be formed in a metal interconnect layer, along with various interconnect elements of the integrated circuit device. The e-fuse element may be formed by depositing and patterning a diffusion barrier layer over the metal e-fuse terminals and interconnect elements formed in the metal interconnect layer. The e-fuse element may be formed from a material that provides a barrier against metal diffusion (e.g., copper diffusion) from each of the metal e-fuse terminals and interconnect elements. For example, the e-fuse element may be formed from titanium tungsten (TiW) or titanium tungsten nitride (TiW2N).

A fuse is a resistive link, which can be permanently programmed between a low resistance state and a high resistance state. An e-fuse responds to an electric current (as opposed to laser) to cause the change of resistance (programming) from the low resistance state (e.g. less than 1 Kohm) to the high resistance state (e.g. greater than 100 Kohm). E-fuses are useful in a wide range of applications, for example (a) for protection from electrostatic discharge (ESD) during manufacture and handling, (b) for removing or replacing a defective device from a circuit, (c) for programming one-time programmable memory, for example ROM (Read Only Memory), OTP (One Time Programmable memory), or PROM (Programmable Read Only Memory), without limitation, (d) for electronic digital trim of passive components (e.g., resistors, capacitors, or inductors), or (e) to provide chip security by preventing unauthorized access.
In the integrated circuit industry, the predominant type of e-fuse is the silicide polysilicon e-fuse, in which a silicide region formed on the polysilicon forms a low resistance path before programming, and is purposefully destroyed by high current during programming, which changes the fuse to the high resistance state. FIGS. 1A and 1B show a top view and side cross-sectional view, respectively, of a conventional silicide polysilicon e-fuse 100. As shown, the silicide polysilicon e-fuse 100 includes a silicide polysilicon fuse element contacted by tungsten terminals. The silicide polysilicon fuse element may be programmed through electro migration, wherein a large current, for example 10 mA, is driven through the silicide polysilicon fuse element, which ruptures the silicide polysilicon fuse element and thereby switches the e-fuse from a low resistance state to a high resistance state.
However, the silicide polysilicon e-fuse is not available in certain high-k dielectric and metal gate transistor technology. In contrast to silicide polysilicon e-fuse, an e-fuse formed of metal is generally preferred in applications utilizing those high-k dielectric and metal gate transistor technologies due to its low melting point and ease of programming using electromigration. Thus, in some advanced CMOS designs, interconnect metal or via is used as an e-fuse without introducing a dedicated e-fuse metal, through thermally accelerated metal electromigration. However, this process is typically very complicated and requires specialized programming because only some parts of the circuit (components associated with the e-fuse) are programmed by electromigration, while other parts of the circuit (e.g., normal CMOS components) must be protected from electromigration.
To increase programming margin and overall device reliability associated with integrated e-fuses formed of metal, there is a need for improved e-fuses with a dedicated e-fuse metal that can be fabricated cheaply, reliably, and with high density.
For example, there is a need for e-fuse modules formed in copper interconnect, for integration with common IC manufacturing processes. However, using copper interconnect for e-fuse modules presents particular challenges. For example, copper diffuses fast during and/or after interconnect structure manufacturing, which may form deep-level traps and substantially degrade transistor performance. Thus, copper may be encased in a barrier layer to prevent or inhibit such diffusion. A dielectric (non-conductive) barrier layer of silicon nitride (SiN) or silicon carbide (SiC) is commonly formed over copper structures after a copper chemical mechanical polishing (CMP). However, this dielectric barrier formed over the copper structures presents a challenge for connecting an e-fuse element (film) formed of metal to a pair of copper structures (e-fuse terminals). In addition to the challenge of copper diffusion, copper is also susceptible to corrosion. Thus there is a need for e-fuses, formed of metal, constructed in a copper interconnect structure which copper interconnect structure is protected against copper diffusion and corrosion. Further, there is a need to reduce or minimize the number of mask layers needed to construct such integrated e-fuses.

Integrated circuit e-fuse having an e-fuse element providing a diffusion barrier for underlying e-fuse terminals


A new class of fundamental devices and methods for their manufacture and use. The bulk magnetic field replicators of the present invention require no precision machining or alignment to accurately reproduce magnetic fields of any complexity, nor extreme positional stability to maintain superconductivity. Such bulk devices may be formed of either low or high critical temperature superconductive materials, but are particularly adapted to formation from high critical temperature materials.

This invention relates generally to a class of devices known as magnetic field replicators and to methods for their creation, operation and uses. Although it is not so limited, it is particularly useful for replicating complex fields with high precision, low weight and low cost, and in short real times. It may also replicate strong or very strong magnetic fields, and can produce magnets of large surface area. In addition, these replicators can also be used in much smaller devices such as for field magnets of generators.
There are many applications for which a high strength magnetic field and/or a complex, highly precise field are not only highly desirable but virtually mandatory. The conventional procedure has been to employ windings about an iron core machined to produce the shape and intensity of field desired. While this approach has been adequate in many circumstances, it suffers from some notable deficiencies. Typically, the iron or ferrous material core must be machined to a very close tolerance, often 0.001 of an inch, which makes the resulting product quite expensive. Obtaining such a precisely-machined magnet several meters in size to produce a field strength of 20,000 gauss might cost on the order of a hundred thousand dollars or much more, and the final product might well weigh from one ton to tens of tons. Higher strength magnets of conventional design are obtainable only at still higher costs and weights, perhaps exponentially higher. Additionally, since iron magnets wound with conventional wire dissipate a great deal of power, sometimes hundreds of kilo-watts, operating such magnets can be both quite costly and difficult to schedule with power companies.
Since iron saturates in the region of 20,000 to 30,000 gauss, higher fields are presently created by windings of superconducting wire which, due to the high fields, are subject to tremendous forces. If such wire moves or flexes by just a very small amount, the superconducting property is often lost or, in the terms of the art, a "quench" is said to have occurred. Creating high strength superconducting magnets requires an exceedingly great precision of support and windings, at a corresponding cost. For example, a solenoidal, superconducting wire-wound magnet, two meters long and one meter in diameter, might cost several million dollars.
Attempts have been made, in instances where a number of identical field sources were desired, to manufacture only one such expensive conventional magnet and to duplicate the field by placing a magnetizable material in close proximity to the high strength field. With the discovery of superconducting material—i.e., material capable of conducting an electric current with no resistance and no losses—it was thought logical to try to impress the desired field pattern in a magnet of such material. However, another characteristic of such materials is the tendency to expel all internal magnetic fields when the critical temperature, Tc—the temperature below which superconductivity occurs—is achieved. This characteristic is now known as the Meisner Effect. Conflicting characteristics of the superconducting materials therefore existed—i.e., a material thought to be ideal in many respects was at hand, but the superconductivity material would expel the impressed magnetic field upon achieving the superconducting state.
In the mid-1970's, Mario Rabinowitz and colleagues at the Stanford Linear Accelerator Center, using materials which exhibited superconductivity only when within a few degrees of absolute zero, discovered that by causing imperfections in the material, for example by work hardening, the magnet would not expel all magnetic lines of force from within the material when, while subject to a magnetic field, its temperature was taken below the critical temperature. This discovery was dubbed the "Incomplete Meisner Effect", and the retention of a very strong magnetic field by superconducting materials is now known as the "Very Incomplete Meisner Effect", or VIME.
Superconducting materials for which the Meisner Effect is literally true—i.e., materials which completely expel all of their internal magnetic fields when the magnetic field strength is less than the critical field strength, HC—are known as Type I superconductors. Superconducting materials for which the Meisner Effect is not literally true—i.e., those which demonstrate either the Incomplete Meisner Effect or the Very Incomplete Meisner Effect—are known as Type II superconductors. Additionally, in Type I SC's, the magnetic field is totally penetrating—i.e., completely contained within the body of the SC—when the strength of the magnetic field is greater than the critical field strength, HC, and the property of superconductivity is lost, whereas in a Type II SC, the magnetic flux lines penetrate the body when the field strength is greater than a first critical level HCl, but the superconductivity property is not lost until the field strength exceeds a second critical level, HC2. This "window", for the Incomplete or Very Incomplete Meissner effect, allows the theoretical possibility for retention of strong magnetic fields in bulk SC materials, which is fundamentally different from creation of such fields by currents through wires or ribbons.
Further, all superconducting materials must be maintained at temperatures below their respective critical temperatures, Tc, in order to maintain their superconductivity; the respective temperatures at which such materials lose their superconductivity properties forms the basis for a further classification of such materials. Superconductors which are able to maintain their superconductivity property only within a few degrees of absolute zero are known as low critical temperature or low Tc superconductors, while superconductors which are able to maintain that property at much higher temperatures are known as high Tc superconductors. In a practical sense, materials which become superconducting below the temperature of liquid nitrogen require liquid helium as a coolant. Materials which become superconducting above the temperature of liquid nitrogen can use liquid nitrogen as a coolant. Since liquid nitrogen is much cheaper and easier to handle than liquid helium, it is convenient, from a practical standpoint, to take the dividing line between low Tc and high Tc superconductivity as the temperature of liquid nitrogen even though this temperature may not represent the actual demarcation line between these two classes of materials. In a historical sense, the high Tc superconductors were the first to exhibit superconductivity above temperatures of about 30 Kelvin.
Rabinowitz' work, so far as is known to date, is limited to the class of superconductors known as metallic superconductors, which to date are further limited to temperatures within a very few degrees of absolute zero (30 K or less). This limitation requires the use of liquid helium as the coolant, which not only greatly increases the cost but which, due to extreme difficulties of handling, greatly limits the practical applications of such devices. According to "Dependence Of Maximum Trappable Field On Superconducting Nb3Sn Cylinder Wall Thickness", M. Rabinowitz et al., Applied Physics Letters 30, 607, 1977, Rabinowitz's results were achieved through the use of multiple layers of Nb3Sn foils formed in the shape of a cylinder by helically wrapping the ribbons of superconducting foil around a mandrel. While satisfactory for laboratory experiments, the practical limitations of such delicately-constructed materials are obvious.
U.S. Pat. No. 4,176,291, "Stored Field Superconducting Electrical Machine And Method", to Rabinowitz, discloses the employment of a metallic superconductor known as "A-15, beta-tungsten structure" superconductor formed in the shape of cylinders. These cylinders are formed in concentric layers of superconducting materials and thermally and electrically conductive materials in order to insulate the magnetic field replicator from thermal and electromagnetic forces and from heat build up which might otherwise cause the extremely low Tc of the Rabinowitz device to be exceeded, with resultant loss of superconductivity and the impressed magnetic field. Rabinowitz discloses the use of the "warm process" method to impress the desired field in his specialized cylinder, and states that with that process he has been able to store a magnetic field in the superconductor of up to about one-half Hc2.
U.S. Pat. No. 4,190,817, "Persistent Current Superconducting Method And Apparatus", to Rabinowitz, discloses, for low Tc, metallic superconductors, various means for varying the field, for creating complex and/or spatially large fields, and for miniaturizing fields, as well as means for increasing the fidelity, magnitude, and stability of the magnetic field stored in such low Tc superconductors.
U.S. Pat. No. 4,096,403, "Superconducting Hybrid Magnetic Flux Pump", also to Rabinowitz, discloses various arrangements for magnetic flux pumps. None of the Rabinowitz references discloses high Tc, bulk superconductors.
With the relatively recent discovery of the new class of superconducting materials known, relatively, as 'high temperature' superconductors, a number of researchers have attempted to use such materials to replicate high intensity magnetic fields. However, it has been found that this may not be accomplished simply by extending Rabinowitz' work to such materials; rather, this new class of superconducting materials has its own, unique problems which must be overcome before such materials may successfully be used as magnetic field replicators.
One such problem not found with low Tc SC's, and a paramount problem for high Tc SC's, is the tendency for the retained or "trapped" field strength, BT, of such materials to undergo time decay. Representative of this relationship is the graph of FIG. 15 of retained field strength, BT, as a function of time displayed logarithmically:
The field strength, which decays with time logarithmically, does so initially at a precipitous rate, and then abruptly changes to a more moderate rate of decline. The decay rate following this inflection point is referred to as "Creep", or "flux creep", analogous to the dislocation line movement in crystalline materials. With low Tc SC's, some of the field strength is lost—i.e., some magnetic flux lines escape—within very short time periods (on the order of 10 seconds), but thereafter the field appears to stabilize and, within the time limits of the Rabinowitz experimenters, the loss appears to be virtually zero. In the aggregate, with low Tc materials, creep is minor, and the trapped field may persist for millenia. In the newer high Tc materials, the creep can reduce the trapped field by several percent in one week and is referred to as "Giant Creep". While some applications are possible in high Tc materials in spite of the Giant Creep phenomena, many more applications would be possible if the phenomena were eliminated, significantly reduced, or otherwise overcome or controlled.
Still another difficulty confronting the high temperature superconductivity researcher is that the superconductivity property is not isotropic, i.e., is not uniform in all directions. Typically, the SC property is manifested in only two directions, i.e., a plane, and is smaller, or non-existent in a direction perpendicular to this plane. It was long thought that the SC phenomenon was confined to a plane at the surface of a superconducting conductor, and it was therefore thought that this limited available volume for trapping would impose significant limitations on the strengths of the fields which could be trapped. Simultaneously, since it was also thought that the fields could be trapped only in the direction perpendicular to the SC plane, serious reservations existed in most quarters of about the prospects of ever developing strong, practical, high Tc SC magnetic replicators.


A combined sealing system for connecting a panel to a frame includes a first sealing system and a second sealing system. The first sealing system connects a first surface of the panel to a first surface of the frame, and the second sealing system connects a second surface of the panel to a second surface of the frame. The combined sealing system has an unlocked configuration and a locked configuration. In the unlocked configuration, the panel moves relative to the frame along a plane substantially parallel to a longitudinal axis of the first or second surfaces of the frame. In the locked configuration, each of the first and second sealing systems separately prevent movement of the panel relative to the frame along the plane.

1. Field of the Invention
The disclosure relates generally to sealing systems for use with panels, such as a door or a window, within a frame and, more specifically, to a sealing system for providing an improved seal between meeting stiles of adjacent panels and between a panel and frame.
2. Description of the Related Art
Certain types of panels, such as doors and windows, are positioned within openings of a wall and/or other structures using a frame. These panels may also open and close by sliding back and forth within the frame. An issue associated with these types of panels is the integrity of the seals between the panels and the frame and between adjacent meeting stiles of a pair of panels. In many instances, these seals are an insufficient barrier in preventing the transfer from one side of the panel to the other side of the panel of such environmental elements as noise, weather, water, and insects.
Examples of conventional connections between the meeting stiles of a pair of panels and between a frame and a panel are respectively illustrated in FIGS. 1A and 1B. In FIG. 1A, a first panel 10A and a second panel 10B each include a bottom rail 25 and a glass panel 32. Also, the first panel 10A includes a first meeting stile 20A that engages a second meeting stile 20B of the second panel 10B at interlocking extensions 22A, 22B of the first and second meeting stile 20A, 20B. Each extension 22A, 22B may respectively include brush seals 24A, 24B that engage a portion of the other extension 22A, 22B. These seals 24A, 24B, however, are not always capable of preventing elements, such as noise, weather, water, and insects, from breaching the seals. Moreover, if the panels 10A, 10B are slightly misaligned, one or both of the seals 24A, 24B may not properly engage the opposing interlocking extension 22A, 22B.
FIG. 1B illustrates the connection between a sill 38 of a frame 41 and a bottom rail 25 of a pair of panels 10A, 10B. Each bottom rail 25 includes a roller assembly 30 having a wheel 37 that is attached to the bottom rail 25 with an axle 40. The panels 10A, 10B slide relative to the frame 41 using the wheels 37 along a track 39 attached to the sill 38. However, gaps exists between the rollers 70 and the bottom rail 25 and between the wheels 37 and the track 39 since the wheels 37 only engage the track 39 at certain positions. As a result of these gaps, an effective seal is not provided between the frame 41 and the panels 10A, 10B.
Attempts have been made to address these issues by using various types of weather stripping between the panels and frame. For example, the weather stripping may be strip of felt, foam, or a pile of flexible synthetic material. In many instances, however, this weather stripping fails to act as a sufficient seal between the panels and frame. There is, therefore, a need for a sealing system that can be employed between a frame and panel or between adjacent panels that prevents the transfer from one side of the panel to the other side of the panel such environmental effects as noise, weather, water, heat/cold, and insects
Another issue prevalent associated with the seals between a frame and panel or between adjacent panels is that these seals can become disjoined. Either intentionally or unintentionally, the alignment between the frame and panel or between adjacent panels may be disturbed which can degrade the quality of the seal, since, in many instances, the integrity of the seal relies upon these members having certain positional relationships relative to one another. There is, therefore, also a need for a sealing system that maintains the positional relationships between the frame and panel or between adjacent panels.

Combined sealing systems for sliding door/window


A photosensitive glass processing method, and article made thereby, which makes it possible to facilitate the etch depth control, minimize the surface roughness of the etched surface, improve the operating efficiency in single-side etching process, and increase the yield includes a first exposure step, in which laser light is applied to the obverse side of photosensitive glass from above it through an exposure mask by using a pulsed laser that covers the sensitivity wavelength range of the photosensitive glass, thereby forming a first exposed portion, the energy intensity per pulse of laser light being set at 10 mJ/cm.sup.2, and the total exposure energy being set at 500 mJ/cm.sup.2 ; a second exposure step, in which laser light is applied to an end surface of the photosensitive glass through another exposure mask, thereby forming a second exposed portion, the energy intensity per pulse of laser light being set at 10 mJ/cm.sup.2, and the total exposure energy being set at 15,000 mJ/cm.sup.2, wherein the first exposed portion, which is crystallized by heat treatment, is easy to etch, while the second exposed portion, which is crystallized by the same heat treatment, is difficult to etch, and a groove is formed at the position of the first exposed portion.

1. Field of the Invention
The present invention relates to a method of processing photosensitive glass by etching.
2. Description of the Prior Art
There has heretofore been a method of processing photosensitive glass by etching to form fine shapes, for example, ink-jet printer heads. This method includes the steps of exposing a desired portion of photosensitive glass by irradiation with an ultraviolet lamp (exposure step), crystallizing the exposed portion by heating the photosensitive glass to a temperature in the range of 500.degree. C. to 700.degree. C. (heat development step), and removing the crystallized exposed portion by dissolving it in an etching liquid, i.e., hydrofluoric acid solution, (etching step). As the ultraviolet lamp, for example, a high-pressure mercury lamp is employed.
Meantime, there is a process where only one side of photosensitive glass is etched to form groove portions or the like. In this process, the reverse side of the photosensitive glass that is not desired to be etched is covered with etching protecting tape or the like before the etching step in order to protect it from the etching liquid, or the reverse side of the photosensitive glass is kept away from the etching liquid by using an etching jig.
In the conventional method, the control of the etch depth of groove portions or the like, which are cut in photosensitive glass by etching crystallized exposed portions formed on the photosensitive glass, is effected on the basis of etching conditions, i.e., etching time, the temperature and concentration of the etching liquid, etc. However, the etch rate of the crystallized exposed portions depends not only on such etching conditions but also on other factors, for example, exposure intensity, heat development conditions, etc. Further, the etch rate varies according to various factors such as fatigue of the etching liquid, contamination of the etching liquid with the crystallized portions of the photosensitive glass which are dissolved by etching, and the way in which the crystallized portions are exposed to the etching liquid. Therefore, the control of the etch depth has heretofore been extremely difficult.
The prior art also suffers from the problem that the etched surface of the crystallized exposed portion has a large surface roughness. In ink-jet printer head application, if the path of ink is formed by a surface having a large surface roughness, air bubbles mixed in the ink are likely to stagnate, producing an adverse effect on the ink injection characteristics. In micro-machining application, the prior art suffers from the problem that a mechanical drive part cannot move smoothly because of large friction.
Further, in the case of single-side etching, it takes time and labor to cover the photosensitive glass with protecting tape before the etching process and strip the tape thereafter. In addition, the photosensitive glass substrate may be damaged when the tape is stripped therefrom. The use of a jig for the etching process involves the problems that such an etching jig is costly, and that since force is applied to the photosensitive glass when attached to the jig, the glass is readily broken during the etching process, which invites a lowering in the yield.

Method of processing photosensitive glass with sections of differing exposure energies and article


Apparatus and method of communicating data employing current pulses transmitted by an implanted device through living biological tissue to an external device. The method also contemplates transmission of current pulses from the external device through living biological tissue to an implanted device. Uniquely configured antenna electrodes are preferably employed in the implanted device. Increase in signal-to-noise ratio is achieved through synchronization. The method may be employed in diagnostic, therapeutic and general monitoring activities in connection with human beings.

1. Field of the Invention
The present invention relates to a method and associated apparatus employed in wireless two-way communication of data by means of current pulses traveling through living biological tissues and, more specifically, it contemplates the use of an implantable device which may be implanted, for example, in a patient's brain, torso or abdomen in cooperation with an external computerized device for diagnostic, monitoring or therapeutic purposes.
2. Description of the Prior Art
The value of using invasive procedures and devices in diagnosing, monitoring or treating patients has long been known in the medical environment. It has been known, for example, to employ a pacemaker for regulating heart functions. Also, deep brain electrical stimulation for the treatment of Parkinson's Disease has been known.
It has also been known to suggest the use of implantable devices which are in communication with an external computerized device, such as by radio frequency (RF) signals or light or wired connection, for example.
It has also been known for various purposes to suggest two-way communication with wireless base and remote stations wherein data may be communicated. See, for example, U.S. Pat. No. 6,289,237.
Among the problems with the prior art utilizing wired systems are the risk of infection and reduced mobility of the patient.
Among the problems with prior art RF systems have been the requirement for substantial size, difficulty in recharging batteries and signal-to-noise ratio. Also the energy required to convert between the signal and the RF waves can be substantial.
There remains, therefore, a substantial need for an implantable device which will efficiently and accurately receive signals from an external device and deliver signals to the external device for medical diagnosis, monitoring and therapeutic purposes.

Method of data communication with implanted device and associated apparatus

University of Pittsburgh - Of the Commonwealth System of Higher Education


A system for sealing a joint gap between structural substrate panels such as walls, ceiling and floors making use of a sealing member including a mounting section fixedly secured to one of the surfaces and a covering member extending outwardly therefrom into contact with the other substrate member. These walls, ceilings and floors can be movable relative to one another and thus the present invention provides a mechanism for sealing the joint gap between the substrates while allowing them to move with respect to one another. This is achieved by fixedly securing the sealing member to one of the substrates and urging it into abutting engagement with respect to the other substrate.

1. Field of the Invention
The present invention deals with the field of devices for sealing the joint gaps between substrate surfaces used structurally. These joint gaps normally occur between floors and walls or between ceilings and walls or between walls. However, such gaps can occur between any two construction substrates.
The primary problem here is that these individual substrates which are normally positioned at an angle with one another and normally at approximately a ninety degree angle with respect to one anther are capable of moving independently of one another. Thus the size of the joint gap can vary significantly as the wall, ceiling or floor flexes relative to the adjacently positioned similar surface. Heretofore the means for sealing such areas has been to insert an insulation batting or to spray foam into the joint gap. The problem is that as the two adjacent substrates move or otherwise flex with respect to one another the size of the gap becomes greater and becomes smaller at various times depending on the type of use and other conditions. When the joint gap widens with some materials the gap becomes too wide for the insulating or blocking material and sealing of the joint gap is compromised. On the other hand when the substrates flex toward one another the amount of this flexing is limited by the minimum width to which the batting or foam can be compressed without failure. Thus these unique conditions experienced by two movable substrates adjacently positioned to define a joint gap therebetween are greatly inhibited by the current means for sealing of the gap. The present invention provides a means for sealing of this gap without requiring the positioning of any component directly in the gap and in this way allows complete capability of flexible movement between the two substrates while maintaining an uncompromised seal extending over the joint gap therebetween.
2. Description of the Prior Art
Many patents have been granted on systems for providing interfacing structure between walls, ceilings and/or floors many of which are defined as "head-of-wall" control system. Other currently existing patents attempting to solve this problem or dealing peripherally with structures for sealing between structural substrates are shown in the following patents. See U.S. Pat. No. 1,357,713 patented Nov. 2, 1920 to A. M. Lane and assigned to Monarch Metal Products Company on a "Weather Strip For Expansion Joints"; and U.S. Pat. No. 3,331,294 patented Jul. 18, 1967 to R. A. Waller and assigned to Kins Developments Limited on a "Flexible Insert"; and U.S. Pat. No. 4,566,242 patented. Jan. 28, 1986 to C. L. Dunsworth and assigned to Metalines, Inc. on a "Smoke And Heat Barrier"; and U.S. Pat. No. 4,967,527 patented Nov. 6, 1990 to H. J. Gohlke and assigned to Metalines, Inc. on "Expansion Joint Fire Barrier Systems"; and U.S. Pat. No. 4,977,719 patented Dec. 18, 1990 to A. R. LaRoche et al on a "Fire Resistant Expansion Joint"; and U.S. Pat. No. 4,999,962 patented Mar. 19, 1991 to H. J. Gohlke et al and assigned to Metalines, INc. on "Expansion Joint Fire Barrier Systems"; and U.S. Pat. No. 5,029,423 patented Jul. 9, 1991 to A. T. Kornylak and assigned to Kornylak Corporation on a "Vibration Resistant Building Construction"; and U.S. Pat. No. 5,140,797 patented Aug. 25, 1992 to H. J. Gohlke et al and assigned to Balco, Inc. on "Expansion Joint Fire Barrier Systems"; and U.S. Pat. No. 5,259,162 patented Nov. 9, 1993 to J. D. Nicholas and assigned to Pawling Corporation on "Multi-Functional Wall Cover For Architectural Joints"; and U.S. Pat. No. 5,263,293 patented Nov. 23, 1993 to H. J. Gohlke et al and assigned to Balco, Inc. on "Expansion Joint Fire Barrier Systems"; and U.S. Pat. No. 5,297,372 patented Mar. 29, 1994 to J. D. Nicholas and assigned to Pawling Corporation on "Elastomeric Sealing System For Architectural Joints"; and U.S. Pat. No. 5,461,838 patented Oct. 31, 1995 to P. S. Heller on a "Fire Barrier"; and U.S. Pat. No. 5,560,165 patented Oct. 1, 1996 to L. Hoefsloot et al and assigned to KONE Oy on "Joint Between A Landing Door And Wall Structures"; and U.S. Pat. No. 5,560,166 patented Oct. 1, 1996 to J. Burke et al and assigned to Foster Wheeler Energia Oy on an "Expansion Joint With Protective Shielding"; and U.S. Pat. No. 5,755,066 patented May 26, 1998 to D. W. Becker on a "Slip Track Assembly"; and U.S. Pat. No. 5,765,332 patented Jun. 16, 1998 to H. V. Landin et al and assigned to Minnesota Mining and Manufacturing Company on a "Fire Barrier Protected Dynamic Joint"; and U.S. Pat. No. 5,887,400 patented Mar. 30, 1999 to D. J. Bratek et al and assigned to Watson Bowman Acme Corp. on an "Expansion Control System"; and U.S. Pat. No. 5,913,788 patented Jun. 22, 1999 to T. r. Herren on a "Fire Blocking And Seismic Resistant Wall Structure"; and U.S. Pat. No. 5,921,041 patented Jul. 13, 1999 to J. D. Egri, II on a "Bottom Track For Wall Assembly"; and U.S. Pat. No. 6,058,668 patented May 9, 2000 to t. R. Herren on a "Seismic And Fire-Resistant Head-Of-Wall Structure"; and U.S. Pat. No. 5,974,750 patented Nov. 2, 1999 to H. V. Landin et al and assigned to 3M Innovative Properties Company on a "Fire Barrier Protected Dynamic Joint"; and U.S. Pat. No. 6,112,488 patented Sep. 5, 2000 to J. R. Olson et al and assigned to Unifrax Corporation on "Fire Barrier Material And Gaskets Therefor"; and U.S. Pat. No. 6,128,874 patented Oct. 10, 2000 to J. R. Olson et al and assigned to Unifrax Corporation and Construction Specialties, Inc. on "Fire Resistant Barrier For Dynamic Expansion Joints"; and U.S. Pat. No. 6,131,352 patented Oct. 17, 2000 to V. Barnes et al on a "Fire Barrier"; and U.S. Pat. No. 6,176,053 patented Jan. 23, 2001 to R. C. A. St. Germain and assigned to roger C. A. St. Germain on a "Wall Track Assembly And Method For Installing The Same".

Method and apparatus for sealing a joint gap between two independently movable structural substrates


In an active control noise-cancelling muffler system, a substantially complete acoustic and mechanical decoupling of the noise-cancelling signal pipe from the gas exhaust pipe is achieved. The noise-cancelling signal delivery pipe is physically isolated and separate from the gas exhaust pipe, and is mounted separately. The outlet end of both pipes are essentially coplanar. Using pressure sensors on the tubes, the system also accurately and continuously electronically replicates the mixing of the exhaust noise and the noise-cancelling acoustic energy that goes on in the space immediately beyond the two outlets. This electronic signal is a useful alternative for a direct measure of the resultant two acoustic waves when they mix in the space beyond the tube outlets, and allows the system to continuously estimate the degree of success of noise cancellation without having to measure it directly when impractical. The system uses measures of pressure and temperature of the two tubes to continuously adjust a transducer drive signal that drives the sum of the pressures at the two tube outlets toward zero. An advantageous algorithm for the control process is identified.

Active noise-cancelling muffler systems used with internal combustion engines typically include means for monitoring selected parameters of the exhaust system and gas flow; and using the parameters, developing a noise-cancelling acoustic waveform. The "counter-acoustic wave" typically is formed first as an electrical waveform generated by a controller. The controller may be a computer or chip driver connected to an amplifier for a transducer that generates the cancelling signal. The cancelling wave and the exhaust gas energy continuously subtractively combine to effect the desired noise reduction.
In active noise-cancelling muffler systems, it is necessary to control the noise-cancelling acoustic signal both spatially and temporally so that the negative-going pulses of the cancelling wave coincide with the positive-going pulses of the exhaust gasses. The prior art teaches a variety of control strategies, using various physical structures to contain the transducer and launch the counter-acoustic wave. However, the physical design of the systems as well as the efficiency of the control signal leave much to be desired in terms of cost and reliability.
The controller requires accurate information as to the upstream exhaust gas reference pressure in order to generate a useful transducer input signal. One problem with many such systems of the prior art is that acoustic or mechanical coupling occurs between the counter-acoustic wave generator and the exhaust system of the IC engine. Readings of the exhaust gas reference pressure that are perturbed by mechanical or acoustical coupling from the noise cancelling apparatus, complicate the controller's function by requiring more complex and time-consuming computations to compensate for the perturbations. If the actual on-going reference gas pressure fluctuations is substantially obsecuted by such perturbation, the functionality of the system may be defeated altogether.
A continuously effective noise reduction system requires constant adjusting of the cancelling waveform to changing conditions which include exhaust temperature, frequency and amplitude. Ideally, despite the changing conditions, the exhaust gas acoustic energy is driven by the cancelling waveform toward zero at all times.
The degree of success in achieving full cancellation depends in part on continuously measuring the actual noise reduction occurring at the exhaust pipe outlet. The measurement of noise reduction is critical in determining controller inputs that will cause the transducer to continuously drive the exhaust gas noise to zero.
In most prior art active control noise-cancelling vehicular muffler systems, because the cancelling waveform and the exhaust noise waveform are acoustically and mechanically coupled in the same pipe, it is straightforward to measure the actual noise reduction simply by placing a single sensor at the common outlet. If, on the other hand, the noise-cancelling generator and the exhaust pipe are physically decoupled, the prior art expedient for measuring actual noise reduction is not available. Further, it is not practical for cost and reliability reasons to place a pickup microphone in the space beyond the exhaust pipe outlet to measure the actual reduced-noise exhaust gas amplitude. A practical measure of the spatial and temporal components of the noise-reduced exhaust gas pressure for use with decoupled systems is needed.

Active noise-cancellation system for automotive mufflers