This invention relates to fuel elements for nuclear reactors, and more particularly to braces, spacers, or support lattices which are usually placed at predetermined distance(s) along the length of the fuel elements in order to provide lateral bracing and spacing, and to maintain the fuel elements in fixed positions.
In a nuclear reactor, the reactor core contains nuclear fuel which is typically in the form of fuel rods grouped together in fuel assemblies. The fuel assemblies are usually mechanically identical and can therefore, be interchangeable. Groups of fuel assemblies are arranged into a matrix to form a core capable of controlled fission reaction.
Each fuel rod is typically a long member approximately 0.4 inches in diameter and 8 to 15 feet long containing fuel usually in the form of a stack of fuel pellets which are surrounded by tubular cladding. The fuel rods which make up an assembly are grouped together to form a plurality of longitudinally extending members which are supported vertically by two parallel end plates, an upper and a lower tie plate. These plates are usually connected to one another by tie rods, or other structural elements.
Each fuel assembly or bundle may also include non-fuel bearing members. Examples include guide tubes to form passageways for control rods which assist in controlling the rate of fission, instrumentation tubes for in-core instrumentation, spacer capture rods, and water rods to modify the neutron moderation in the assembly. The spaces between adjacent fuel rods create flow channels through which coolant and/or moderator can circulate. In light water reactors, the coolant and moderator is water. Lateral bracing and spacing of the fuel rods in the fuel assembly are provided by spacers or spacer grids.
The fuel assembly or bundle, whether in a pressurized water reactor, boiling water reactor, high temperature gas cooled reactor, or any other type of reactor, functions in part to maintain the fuel rods in a fixed position, ideally free of vibration and restrained from bowing or other movement during normal and other operating conditions. In addition, by maintaining the fuel rods in fixed positions, proper cooling and neutron moderation can be achieved. Devices that assist in maintaining the fuel rods in fixed positions in the fuel assembly or bundle and which thereby facilitate proper fuel cooling are spacers.
Spacers or spacer grids which provide lateral bracing are typically designed to allow differential axial expansion of the fuel rods. Springs incorporated in the spacer grids are most frequently used to permit some sliding of the fuel rods with respect to the spacer grids. In some of the designs, the spacer grid is free to move axially a small amount to accommodate minor changes in the axial length of the fuel rods during irradiation.
If spacers wee to be rigidly connected to the fuel rods as well as to structural members of the fuel assembly, then relative axial movement due to rod growth and thermal expansion of adjacent rods can cause local fuel rod skewing and bowing.
By being positioned at regular intervals, spacers maintain rod-to-rod spacing along the length of the fuel assembly. Spacers are typically made of zirconium based alloy sheet material or sometimes from Inconel or stainless steel, and are built up from a relatively large number of different intricately shaped strips that are fitted together by hand and subsequently welded. Sometimes, short sections of tubing are used that are welded to one another along parts of their edges. The spacers have an egg crate shape and each spacer cell includes dimples and/or springs to maintain the desired rod-to-rod spacing. Thus, the springs and dimples keep the fuel rods in their proper lateral positions. But, under the influence of irradiation, the springs are prone to relax and this can lead to undesirable changes in fuel rod pitch (i.e. rod-to-rod spacing) or it may cause gaps or spaces to develop between fuel rods and the springs and dimples, and increases the likelihood that the rods and/or spacer grids will vibrate. Such gaps, changes in fuel rod pitch, and vibration may lead to fuel rod fretting and failure.
Springs necessarily contact the fuel cladding and can cause fretting even if they are not subject to relaxation. Furthermore, as the fuel is irradiated, the fuel rods undergo a shrinkage or diameter reduction known as "creepdown" which can result in gaps between the fuel rod cladding and the springs or dimples which in turn can cause or contribute to fuel rod fretting.
Since even the slightest repeated relative movement between contacted fuel rods and spacers can result in fretting of the fuel cladding, minimization of such relative movement is desired. Thus, loads due to thermal expansion of fuel rods, particularly fuel cladding, and associated tensile loads from such expansion must be considered in spacer design.
Spacers should be thin members and have minimal cross-sectional area. Ideally, they are invisible to moderator and coolant flow. Spacer designs which reduce the flow area, also increase flow resistance and restrict coolant flow causing undesirable pressure drops. Thus, the particular physical configuration of a spacer can create or contribute to local or even non-local undesirable flow redistribution, restriction, or distortion.
Typically, the fabrication of spacers requires extensive labor in shaping the separate parts and in assembling and welding these parts to form a spacer grid. Many of these operations can be automated. However, even with automated spacer fabrication, assembly and welding, extensive labor is required in inserting the fuel rods through the spacers to form a fuel bundle. Even with simplified spacer designs, the assembly of spacer and fuel rods is intricate, time consuming and costly. Whenever spacer designs include springs and/or dimples, even non-intricate assembly techniques become particularly labor intensive. Labor costs can be substantial, particularly in light of the rigorous quality control standards that are applied to nuclear reactor components. When spacer design and fuel rod-spacer assemblies include spring or dimple elements, assembly of the fuel rods into a fuel bundle often result in scratching or damaging the fuel rod cladding surface which may lead to rejection of fuel assemblies during pre-operational quality control tests and inspections and/or fuel rod cladding failures during reactor operation.
It would thus be an advantage if spacers did not include springs and dimples or similar contact devices which relax from irradiation.
It would be an additional advantage to limit the repeated relative movement between spacers and the contacted fuel rod cladding.
It would be a further advantage if the actual physical connection between each spacer and fuel rod was not mechanical but was welded, fused, or bonded thereby avoiding the possibility of fretting of the fuel cladding by its spacer.
It would be a further advantage if the effective coolant flow area surrounding each fuel rod is maximized by minimizing the spacer cross sectional surface area which impedes coolant flow.
It would be yet a further advantage if the flow characteristics of a completed fuel assembly with fuel rod spacers could be improved by providing effectively unhindered coolant (e.g. water and steam) flow along the length of the fuel rod between the fuel cladding and its spacer and unhindered coolant flow within the area in the center of adjacent spacers by keeping the center free from any restrictions.
It would be a further advantage to minimize radial changes in the spacer structure in order to minimize changes in the pitch of the fuel rods which may affect the neutronic and thermal performance of the assembly.
It would be yet another advantage if spacers could be made of materials having low neutron cross section as well as having small mass.
It would be an advantage if each fuel rod was connected to its own spacer which remained integral with the fuel rod.
It would be an advantage if each fuel rod/spacer was mechanically identical.
It would be an advantage if the spacers were not rigidly connected to one another but were left free to move in the axial direction and thereby accommodate rod growth and thermal expansion differences between adjacent fuel rods.
It would also be an advantage if the spacer is not connected to the fuel assembly tie or spacer capture rod or to the guide tubes or other structure members so that axial movement of the rods is unrestricted and axial forces are not exerted on the rods thereby minimizing fuel rod bow.
It would also be an advantage if a portion of the spacer could deform in order to accommodate the reduction in diameter of the fuel rods due to creep without changing the distance between the spacer and fuel rod cladding as well as the distance between adjacent spacers.
It would be yet a further advantage if the fuel rod surface would not be exposed to any spacer parts that may cause fretting and if any fretting is to take place, that it would occur on the spacers and not the fuel rods.
It would be an additional further advantage if a spacer having each of the above advantages could be fabricated, tested and inspected at a lower cost than conventional spacers and at the same time improving overall quality and reliability.
It would be another advantage to have spacers which could be attached to and form a sleeve around fuel rods and avoid the prior art method of inserting the fuel rods through and interlacing with the spacer grids.
It would be yet a further advantage if each fuel rod and its integral spacer was such that their assembly into a fuel bundle merely involved stacking of individual fuel rods one on top of another without scratching any of the fuel rods.


The present invention relates generally to a computer implemented method for selecting responsive actions. More specifically, the present invention relates to referencing earlier attempted actions, if sufficiently current, and responding with at least one alternate action.
Systems management software installed on data processing systems are used to detect and catalog events. An event is a signal that indicates a condition of a resource of a data processing system. An event can be, for example, a condition related to a rotation rate of a fan. Accordingly, the event can be a signal generated to identify both the resource and the condition of the resource. Some events can be asynchronously generated from an error condition. In addition, multiple events may be aggregated together to form an event summary. An event summary is an event that describes at least two other events. For example, an event summary can be a count of the number of times a fan speed exceeded a threshold in the previous hour. A resource is a physical data processing hardware or virtual resource, backed by physical data processing hardware. A resource can correspond to a system, subsystem, software program, or device. A resource can have attributes such as a temperature. An event, on the other hand, may be a request such as a hypertext protocol request at a server, or a report that a processor on that server has met or exceeded a temperature. Accordingly, the use of events can be helpful to collect information about a data processing system's status.
One or more events can be indicative of an underlying problem or anomaly. Accordingly, it is helpful that system administrators pay attention to some events under some conditions.


The present invention relates to the flavor industry. It concerns more particularly a process for producing a washed citrus oil flavor, which comprises treating a citrus oil with a mixture of propylene glycol and an alkanol from C1 to C4. The invention also relates to clear beverages flavored with citrus washed oils as formulated by the process of the invention.
The importance in the flavor industry of various citrus oils has resulted in intensive research directed towards processing methods, compositional analyses, quality and utilization.
Detailed compositional data concerning the commercially important citrus oils can be found in several reviews. Extensive lists of various chemical compounds identified as components of orange, grapefruit, tangerine, lemon, and lime oils have been described.
The flavoring characteristics of the citrus oils are a function of the properties of certain components identified in the oils. Furthermore, d-limonene, which is the main component present in citrus oils, acts as a carrier of flavor for other oxygenated compounds mainly responsible for the citrus flavor characteristics.
The extraction from a citrus oil of the oxygenated compounds which are responsible for the citrus flavor is therefore a field of huge interest for the flavor industry. It is well known in the art that flavoring agents may be prepared by extracting from folded oils the oxygenated compounds desired in an extracted or washed flavor profile.
The formulation of washed oil flavors disclosed in the prior art uses water or propylene glycol as solvents for the extraction of useful flavor compounds from a citrus oil. For instance, U.S. Pat. No. 3,809,757 describes the preparation of a flavoring extract from orange oil by selective extraction, using propylene glycol and a hydrocarbon solvent.
The quality of an extract or a wash is mainly characterized by the selectivity of the extracted compounds. The scope sought in the flavor industry when formulating a wash from a citrus oil, is therefore to selectively obtain the key citrus flavor compounds i.e., the oxygenated compounds such as neral, geranial, neral acetate, geranial acetate, decanal, nootkatone, etc. Other requirements such as clearness or flash point requirements are necessary for obtaining an optimized washed oil product.
Now, we have been able to find a novel process for the preparation of a citrus washed oil flavor, combining propylene glycol usually utilized for the extraction of oxygenated compounds, with an alkanol from C1 to C4. This process makes it possible to obtain a surprisingly selective wash of the key flavor compounds present in a citrus oil, which further meets all the requirements of quality and security needed for such a product. The present invention is thus related to a process for producing a citrus washed oil flavor, which comprises treating a citrus oil with a mixture of propylene glycol and an alkanol from C1 to C4. In a preferred embodiment the alkanol is selected from the group consisting of ethanol and isopropanol.
The process of the invention advantageously allows to obtain citrus washed oil flavors which meet the clarity, flash point and usage level objectives required in the art. The washes obtained by the process according to the invention have a flash point greater than 100xc2x0 F. (38xc2x0 C.) (i.e. they belong to the Class I liquids), cut clear in water and have a light, clean profile with the hint of fruit flavor from 0.05 to 0.2%, preferably at a 0.1% use level. Moreover, analyses of the washed citrus oil flavors formulated respectively with and without the use of an alkanol from C1 to C4, clearly indicate that washes produced with the use of some alkanol are superior to those made with propylene glycol on its own. This result will be demonstrated in the comparative tables below, in the case of ethanol.
Unexpectedly, and besides the fact that alkanols from C1 to C4 suffer from the standpoint of their low flash point, we have now been able to optimize the formulation of citrus washed oils using the alkanol at the right level to extract the oxygenated compounds while meeting the flash point limitations.
The proportion of alkanol used in the extracting mixture with propylene glycol can vary in a certain range of values. Typically it can be comprised between 3 and 10% and is preferably comprised between 5 and 7% of the total weight of the composition comprising the citrus oil, propylene glycol and the alkanol.
As mentioned above, among the alkanols from C1 to C4, ethanol and isopropanol are preferred.
The starting product for the process of the invention may be any commercially available citrus oil, in the form of a cold pressed oil, or a folded oil, for instance. Non limiting examples of citrus oils which can be used for the process of the invention include lemon, berry, orange, grapefruit, tangerine, lime, kumquat, mandarin, bergamot and other essential oils or a mixture thereof.
The selectivity of the extraction system may be demonstrated by the comparison between citrus washes made with some ethanol, and washed oil flavors made with 75% propylene glycol: 25% flavor oil, i.e. ethanol free.
The following tables compare the washes obtained with propylene glycol combined with ethanol, and those obtained with propylene glycol on its own.
Table 1 reports the results for a lemon wash while Table 2 reports the results for a grapefruit wash.
It can be easily concluded from the results reported in the above tables that the use of some ethanol is advantageous in extracting the key flavor compounds (i.e. oxygenated compounds such as neral, geranial, neral acetate, geranial acetate, decanal, nootkatone, etc.) from a citrus oil.
The invention also relates to a method to impart, improve, enhance or modify the flavoring properties of a flavoring composition or a flavored product, which comprises adding to said composition or product a citrus washed oil flavor produced by the process of the invention.
Another object of the invention is a flavoring composition or a flavored product such as a clear beverage, comprising a citrus washed oil flavor as an active flavoring ingredient, the proportion of the latter being comprised between 0.05 and 0.2% of the total weight of the composition or product.


1. Field of the Invention
This invention relates generally to memory design. Particularly, this invention relates to a new cell for implementation in the Static Random-Access Memory (SRAM) thus taking advantage of the base current reversal phenomenon in a Complementary Metal Oxide Semiconductor (CMOS) for the construction of compatible high gain gated lateral Bipolar Junction Transistor (BJT).
2. Description of the Prior Art
The conventional CMOS SRAM cell essentially consists of a pair of cross-coupled inverters as the storage flip-flop or latch, and a pair of pass transistors as the access devices for data transfer into and out of the cell. (A large number of different cell configurations are cited in the literature, e.g.,B. Prince, Semiconductor Memories--A Handbook of Design, Manufacture, and Application, 2nd ed., New York: John Wiley & Sons, Inc., 1991). Thus, a total of six Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) or four MOSFETs plus two very high resistance load devices are required for implementing a conventional CMOS SRAM cell. However, to achieve high packing density, it is the usual practice to reduce the number of the devices needed for realizing a CMOS SRAM cell or the number of the devices for performing the Write/Read operation. Especially for the case of very high resistance load devices, increased process complexity, extra masks, and high fabrication cost are required for forming the undoped polysilicon layers or the Thin Film Transistor (TFT) on the oxide and thus saving the chip area; however, the corresponding product yield is not high. Therefore, more efforts are needed to further reduce the areas occupied by the chip while improving the production yield.
The structures of the conventional SRAM are shown in FIGS. 1 and 2. FIG. 1 shows a circuit schematic of a conventional SRAM cell configuration. The cell comprises a pair of cross-coupled inverters, p-MOSFET 11 and n-MOSFET 13, and p-MOSFET 16 and n-MOSFET 14, as the storage flip-flop or latch. In each inverter the gates of p-MOSFET and n-MOSFET are tied together and connected to the output of another inverter. The output of each inverter are the drains of p-MOSFET and n-MOSFET which are tied together. The conventional cell employs a pair of pass transistors, n-MOSFETs 12 and 15, as the access devices for data transfer into and out of the cell. Two column lines DATA and DATA and two row select lines W and W are depicted. This conventional cell requires 6 MOSFETs.
FIG. 2 shows a circuit schematic of a conventional CMOS cell using undoped polysilicon layer or thin-film transistor for providing very high resistance loads 20. FIG. 2 is very similar to FIG. 1 except for the type of the load. This cell requires complex processes and the resulting yield is low. This conventional cell requires four MOSFETs formed on the silicon plus two undoped polysilicon layers or TFTs formed on the oxide.
A Bipolar-CMOS (BICMOS) process has recently been introduced to achieve the above-mentioned object (refer to the paper: K. Sakui, et al. "A new static memory cell based on reverse base current (RBC) effect of bipolar transistor," IEEE IEDM Tech. Dig., pp. 44-47, December 1988). In this BICMOS process, only two devices are needed for a SRAM cell: one vertical bipolar transistor and one MOSFET as a pass device. However, extra processing steps and increased masks are required along with special deep isolation techniques, resulting in high fabrication cost and process complexity. Also, the yield of the SRAM products utilizing such complex BICMOS process is usually low compared with the existing standard CMOS process. Therefore, the SRAM products fabricated in a complex BICMOS process cannot provide sufficient competition to the conventional CMOS SRAM products.
Very recently, a new phenomenon of base current reversal has been observed in a CMOS compatible high gain gated lateral bipolar transistor (refer to the paper: Tzuen-Hsi Huang and Ming-Jer Chen, "Base current reversal phenomenon in a CMOS compatible high gain n-p-n gated lateral bipolar transistor," IEEE Trans. Electron Devices, Vol. 42, No. 2, pp.321-327, February 1995). This new phenomenon has been extensively investigated and has been found to have many applications. This invention employs this new phenomenon in the existing standard CMOS process for realizing a new SRAM cell constructed by only two MOSFETs. This new SRAM also features only one-sided peripheral circuitry for Read/Write action. Therefore, this invention can efficiently save the chip area with high yield since it is fully compatible with the existing low-cost standard CMOS process.


The present invention relates to particles, such as carbon black, having an attached stable free radical which permits the formation of modified particles having blocked radical sources. The present invention further relates to methods of preparing and using such modified particles.
The role of carbon black as a thermal stabilizer in polymeric systems is discussed by W. L. Hawkins, R. H. Hansen, W. Matreyek, F. H. Winslow; J. Applied Polymer Science, vol. 1, pages 37-42, 1959; J. T. Cruver, K. W. Rollmann: J. Applied Polymer Science, vol. 8, pages 1169-83, 1964, and by G. Ivan, M. Giurgina: Revue Rotimaine de Chemie, vol. 29, number 8, pages 639-646, 1984. In each discussion the mechanism is through phenolic and quinone oxygen groups on the carbon black surface behaving either as radical traps or peroxide decomposers. One skilled in the art, however, would consider these sites unavailable as initiating sites for polymerization processes.
Belmont et al. (J. A. Belmont, J. M. Funt: International Rubber Conference, Essen, Germany, June 24-27 1991) identified the presence of peroxide groups, typically in the range of 0.1 to 0.4 micromoles/sq meter, on the carbon black surface. However, the majority (greater than 80%) of the peroxide groups are thermally stable to heat treatment at 200xc2x0 C. and hence cannot be considered to be potential initiating sites for radical polymerization.
Tsubokawa et al. (K. Fujiki, N. Tsubokawa, Y. Sone: Polymer J., vol. 22, number 8, pages 661-70, 1990, and N. Tsubokawa: Prog. Polymer Science, vol. 17, pages 417-70, 1992) discuss growing polymers from an activated carbon black surface by first attaching a reactive group via the oxygen groups on the carbon black surface. Typical examples include the use of glycidyl methacrylate where the glycidyl group reacts with phenolic hydroxyl groups on the carbon black surface providing a vinyl functionality; the reaction of 4,4xe2x80x2 azo bis-(4-cyanovaleric acid) whereby the isocyanate group reacts with phenolic hydroxyl groups and subsequent heating decomposes the azo group to generate an alkyl radical; and the reaction of the phenolic hydroxyl groups with butyl lithium which can then be used as an initiation site for anionic polymerization.
All of these approaches require the presence of oxygen groups on the carbon black surface. Since the level of reactive hydroxyl and carboxylic acid groups, relative to the above approaches, present on a typical furnace or thermal carbon black is typically 0.01 to 0.1 micromoles/sq meter, the number of potential initiation sites is quite low.
Further, subsequent polymerization from these activated sites will most likely occur in the normal manner for free radical polymerization with the chains being irreversible terminated by chain combination reactions, combination with unreacted oxygen groups on the carbon black surface, and/or the addition of chain stoppers. In all cases the polymerization cannot be reinitiated. Accordingly, there is a need to provide particles with attached stable free radicals which overcome the above-described limitations.
In accordance with the purposes of the present invention, the present invention relates to a modified particle which includes a particle having an attached group having the formula:
wherein A represents an aromatic group or an alkyl group; R1 represents a bond, an arylene group, an alkylene group,
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR5, xe2x80x94NHR5, xe2x80x94NR5R5 or xe2x80x94SR5, wherein R5, which can be the same or different, represents hydrogen, an alkyl group or an aryl group; and SFR represents a stable free radical.
The present invention further relates to a modified particle or aggregate wherein the particle or aggregate is a carbon-metal multiphase aggregate, a carbon-silicon containing species multiphase aggregate, a metal oxide, or a metal hydroxide. Attached to the particle or aggregate is a group having the formula:
wherein CoupA represents a Si-containing group, a Ti-containing group, a Cr-containing group, or a Zr-containing group; R8 and R9, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR10, xe2x80x94NHR10, xe2x80x94NR10R10, or xe2x80x94SR10, wherein R10, which can be the same or different, represents hydrogen, an alkyl group or an aryl group; SFR represents a stable free radical, and n is an integer of from 1 to 3.
The present invention further relates to a modified particle with an attached polymer or blocked radical sources, wherein the modified particle has an attached group having the formula:
wherein X represents blocked radical sources or a polymer formed from at least one polymerizable vinyl or diene based monomer, A represents an aromatic group or alkyl group; R1 represents a bond, an arylene group, an alkylene group,
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR5, xe2x80x94NHR5, xe2x80x94NR5R5 or xe2x80x94SR5, wherein R5, which can be the same or different, represents an alkyl group or an aryl group; and SFR represents a stable free radical.
The present invention also relates to another modified particle having an attached polymer. The particle is a carbon-metal multiphase aggregate, a carbon-silicon containing species multiphase aggregate, a metal oxide, or a metal hydroxide. Attached to the particle is a group having the formula:
wherein CoupA represents a Si-containing group, a Ti-containing group, a Cr-containing group, or a Zr-containing group; R8 and R9, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR10, xe2x80x94NHR10, xe2x80x94NR10R10, or xe2x80x94SR10, wherein R10, which can be the same or different, represents an alkyl group or an aryl group; SFR represents a stable free radical, X is blocked radical sources or a polymer formed from at least one polymerizable vinyl or diene containing monomer, and n is an integer of from 1 to 3.
The present invention, in addition, relates to a method for preparing and using these various modified particles. The method includes reacting a particle having an attached vinyl substituted alkyl group with a reactive free radical source and a stable free radical source to form a reaction product. The present application further relates to forming the modified particles with an attached blocked radical source or polymer by reacting the reaction product with a polymerizable vinyl or diene containing monolayer.
The present invention further relates to a method of making a modified particle comprising a particle having attached a group having the formula:
wherein A represents an aromatic group or an alkyl group; R1 represents a bond, an arylene group, an alkylene group,
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR5, xe2x80x94NHR5, xe2x80x94NR5R5, or xe2x80x94SR5, wherein R5, which is the same or different, represents an alkyl group or an aryl group; and SFR represents a stable free radical, wherein said method comprises reacting a) a particle having attached an aromatic group or an alkyl group with a group containing an abstractable proton and which leaves behind a carbon-centered radical when the proton is abstracted with b) a reactive free radical source and c) a stable free radical source.
The present invention, in addition, relates to a modified particle which includes a particle having an organic group having a xe2x80x94SFR group, where the organic group is directly attached to the particle. The modified particle can also be a particle having an organic group having an xe2x80x94Xxe2x80x94SFR group, where the organic group is directly attached to the particle.
The present invention further relates to polymer-modified particles or aggregates where the xe2x80x94SFR group is replaced or terminated with a terminated moiety, for example, a hydrogen atom, a hydroxy group, or a halide group.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.
In one embodiment, the present invention relates to a modified particle comprising a particle having attached a group having the formula:
wherein A represents an aromatic group or an alkyl group which is attached to the particle; R1 represents a bond, an arylene group, an alkylene group,
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR5, xe2x80x94NHR5, xe2x80x94NR5R5, or xe2x80x94SR5, wherein R5, which can be the same or different, represents an alkyl group or an aryl group; and SFR represents a stable free radical.
The particle, to be modified, can be any particle capable of having a group represented by any one of formulas described herein attached thereto, such as formula (I)-(IV). Preferably, the particle has a carbon reactive site (Cxe2x80x94), since in a preferred embodiment for the groups of formula (I) and (III), xe2x80x94SFR and xe2x80x94Xxe2x80x94SFR are preferably attached through a carbon bond on the particle. The particle, for instance, can be carbon products, colored pigments other than carbon products, metal oxides (e.g., silica), metal hydroxides, multiphase aggregates comprising a carbon phase and a silicon-containing species phase, multiphase aggregates comprising a carbon phase and a metal-containing species phase, and the like. The carbon may be of the crystalline and/or amorphous type. Examples of carbon products include, but are not limited to, graphite, carbon black, vitreous carbon, activated charcoal, activated carbon, carbon fiber, and mixtures thereof. Finely divided forms of the above are preferred. Most preferably, the particle is a carbon product, and most preferably carbon black.
The multiphase aggregate containing the carbon phase and the silicon-containing species phase can also be considered a silicon-treated carbon black aggregate and the multiphase aggregate containing a carbon phase and a metal-containing species phase can be considered to be a metal-treated carbon black aggregate as long as one realizes that in either case, the silicon-containing species and/or metal-containing species are a phase of the aggregate just like the carbon phase. The multiphase aggregates do not represent a mixture of discrete carbon black aggregates and discrete silica or metal aggregates and is not a silica coated carbon black. Rather, the multiphase aggregates used in the present invention include at least one silicon-containing or metal-containing region concentrated at or near the surface of the aggregate (but put of the aggregate) and/or within the aggregate.
The aggregate, thus contains at least two phases, one of which is carbon and the other of which is a silicon-containing species, a metal-containing species, or both. The silicon-containing species that can be a part of the aggregate is not attached to a carbon black aggregate like a silica coupling agent, but actually is part of the same aggregate as the carbon phase. For instance, when the multiphase aggregate having a carbon phase and a silicon-containing species phase is examined under STEM-EDX, the silicon signal corresponding to the silicon-containing species is found to be present in individual carbon black aggregates. By comparison, for example, in a physical mixture of silica and carbon black, STEM-EDX examination reveals distinctly separate silica and carbon black aggregates.
The metal-treated carbon blacks are aggregates containing at least one carbon phase and at least one metal-containing species phase. The metal-containing species include compounds containing aluminum, zinc, magnesium, calcium, titanium, vanditimi, cobalt, nickel, zirconium, tin, antimony, chromium, neodyitium, lead, tellurium, barium, cesium, iron, and molybdenum. Preferably, the metal-containing species phase is an aluminum-or zinc-containing species phase. The metal-containing species phase(s) can be distributed through at least a portion of the aggregate and is an intrinsic part of the aggregate.
Further, it is within the bounds of the present invention to have a metal-treated carbon black containing more than one type of metal-containing species phase or the metal-treated carbon black can also contain a silicon-containing species phase and/or a boron-containing species phase. For example, the metal-treated carbon black of the present invention can have an aggregate comprising a carbon phase, an aluminum-containing species phase, and a zinc-containing species phase. Accordingly, the multiphase aggregates used in the present invention can have two or more different types of metal-containing species phases and/or additional non-metal species phases.
Preferably, for purposes of the present invention, the amount of elemental silicon and/or elemental metal present in the multiphase aggregate is from about 0.1 to about 25 wt. %, more preferably, from about 0.5 wt. % to about 10 wt. %, and most preferably from about 0.2 wt. % to about 5.4 wt. %, by weight of the aggregate.
The details of making the multiphase aggregates are explained in U.S. patent application User. Nods.: 08/446,141, filed May 22, 1995; 08/446,142, filed May 22, 1995; 08/528,895, filed Sep. 15, 1995; and 08/750,017, filed Nov. 22, 1996, which is a National Phase Application of PCT No. WO 96/37547, filed May 21, 1996, U.S. patent application Ser. No. 08/828,785, filed Mar. 27, 1997, U.S. patent application Ser. Nos. 08/837,493 filed Apr. 18, 1997 and 09/061,871 filed Apr. 7, 1998. All of these patent applications are hereby incorporated in their entireties herein by reference.
A silica-coated carbon product can also be used as the particle, such as that described in PCT Application No. WO 96/37547, published Nov. 28, 1996, which is hereby incorporated in its entirety herein by reference.
The colored pigment is any pigment which can be modified with the attachment of an aromatic group or an alkyl group. The colored pigments other than carbon products include, but are not limited to, black, blue, brown, cyan, green, violet, magenta, red, yellow, as well as mixtures thereof. Suitable classes of colored pigments include, but are not limited to, anthraquinones, phthalocyanine blues, phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes, heterocyclic yellows, quinacridones, and (thio)indigoids. Specific examples and further information concerning the colored pigments and methods of making colored pigments with attached aromatic groups or alkyl groups are described in PCT Publication No. WO 97/47699, incorporated in its entirety by reference herein.
Particles useful for the present invention may, for example, have primary particles sizes in the general range of from about 10 nm to about 500 nm, and preferably from about 10 nm to about 250 nm, and primary aggregate sizes in the general range of from about 50 nm to about 100 microns, preferably from about 50 nm to about 10 microns, still more preferably from about 75 nm to about 1 micron. The BET surface area of these particles can be any suitable surface area and preferably ranges from about 10 m2/g to about 2000 m2/g and more preferably, from about 10 m2/g to about 1,000 m2/g, and still more preferably from about 50 m2/g to about 500 m2/g; and the particle structure preferably ranges from about 10 cc/100 g to about 1000 cc/g, more preferably, from about 50 cc/100 g to about 200 cc/100 g.
The number of SFR groups directly attached to the particle prior to polymerization can be any amount which can be effectively attached. For instance, the number of xe2x80x94SFR groups may range from about 0.01 mmole/g (of particle) to about 10 mmole/g, or from about 0.1 mmole/g to about 4 mmole/g, or from about 0.05 mmole/g to 4 mmole/g or from about 0.5 mmole/g to about 3 mmole/g, or from about 0.1 mmol/g to about 2 mmol/g.
When the particle is a multiphase aggregate, like a particle comprising a carbon phase and a silicon-containing species phase, preferably the group of formula (I) or (III) is attached at least, if not exclusively, on the carbon phase.
With regard to the A group, which represents at least one aromatic group or an alkyl group, any aromatic group or alkyl group may be used. Unlike the polymerizable monomer discussed later, the aromatic group or the alkyl group is not a polymer and is not polymerized. Examples include, but are not limited to, arylene groups. Preferred arylene groups include, but are not limited to, phenylene and naphthalene groups. The aromatic group includes, but is not limited to, unsaturated cyclic hydrocarbons containing one or more rings. The aromatic group may be substituted or unsubstituted. Aromatic groups include aryl groups (for example, phenyl, naphthyl, anthracenyl, and the like), and heteroaryl groups (for example, imidazolyl, pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, triazinyl, indolyl, and the like). The alkyl group is preferably a C1-C12 alkyl group, and may be branched or unbranched, and is preferably ethyl.
With respect to R1, preferred arylene groups include, but are not limited to, benzene ring containing groups. Preferred alkylene groups include, but are not limited to, C1-C18 alkylene-containing groups. These groups can be linear, branched, or unsaturated. These examples of arylene and alkylene groups can also be considered examples of R4. Preferred alkyl groups for R4 are C1-C20 alkyl groups, more preferably C1-C5 alkyl groups and preferred aryl groups are phenyl, biphenyl, and naphthyl.
With respect to R2 and R3, which can be the same or different, examples of alkyl groups (e.g. C1-C20 alkyl group) include, but are not limited to, methyl, ethyl, propyl, butyl, and the like. Preferably, the alkyl group is a C1-C5 alkyl group. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, and naphthyl. The alkyl and aryl groups mentioned here as well as the arylene and alkylene groups mentioned throughout can be unsubstituted or substituted for purposes of the present invention. R5 can be the same type of alkyl and aryl groups mentioned above with respect to R2 and R3.
SFR, which is the stable free radical, can be any radical capable of capping the remaining portion of the group attached onto the particle. Examples of the SFR include, but are not limited to, nitroxide free radicals such as 2,2,5,5-tetramethyl-pyrrolidinlyloxy and 2,2,6,6-tetramethyl-piperindinyloxy, organic hydrazyl compounds, organic verdazyl compounds, organic aroxyl compounds (e.g., 2,4,6 tri-tertiary butyl phenoxy radical, galvinoxyl (2,6 ditertiary butyl alpha 3,5 ditertiary butyl oxo 2,5 cyclohexadiene-1 ylidene para tolyoxy) radical), aryl alkyl or aryl cycloalkyl where the unpaired electron is on a carbon atom, substituted triphelnyl methyl, substituted triphenyl amine, and derivatives of these compounds.
The SFR used in the present invention preferably has the formulas:
or
xe2x80x83xe2x80x94Oxe2x80x94Ar2xe2x80x83xe2x80x83(VI)
wherein R6 and R7, which can be the same or different, each represent a substituted or unsubstituted alkyl or cycloalkyl group; or R6 and R7 can together form a cycloalkyl group; Ar2 represents a substituted or unsubstituted aromatic group. Representative examples of the alkyl and aromatic groups can be the same as described above with respect to the substitutents R2 and R3.
Another embodiment of the present invention relates to a modified particle or aggregate having a group of formula (II) attached thereto. The particle can be a metal oxide, a metal hydroxide, an aggregate comprising at least one carbon phase and at least one metal-containing species phase, or an aggregate comprising at least one carbon phase and at least one silicon-containing species phase. Attached to this particle or aggregate is a group having the formula:
wherein CoupA represents a Si-containing group, a Ti-containing group, a Cr-containing group; or a Zr-containing group; R8 and R9, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, xe2x80x94OR10, xe2x80x94NHR10, xe2x80x94NR10R10, or xe2x80x94SR10, wherein each R10, which can be the same or different, represents an alkyl group or an aryl group; SFR represents a stable free radical, and where n is an integer of from 1 to 3. Preferably, CoupA is attached to the particle or aggregate, especially in the case of a Si-containing group, via an oxygen radical which can form a part of a CoupA.
Examples of Si-containing groups include, but are not limited to, dimethylsilylmethyl, dialkoxysilylmethyl, and the like. Examples of Ti-containing groups include, but are not limited to, alpha substituted tri-acetyl titanate and the like. Examples of Zr-containing groups include, but are not limited to, dialpha methoxy neopentylzirconate, aluminum zirconates, and the like.
Examples of the substituents R8 and R9 can be the same as the substituents R2 and R3 mentioned above. Likewise, examples of the substituent R10 can be the same as the substituent R5 discussed above. Also, the SFR is the same as discussed above.
The modified particles having the attached group of the formulas, such as formula (I), can be made in the following manner. A particle, such as carbon black, can first have a vinyl substituted aromatic group or a vinyl substituted alkyl group attached to the particle. This attachment can be accomplished by the methods described in PCT International Application No. WO 96/18688 and U.S. Pat. Nos. 5,630,868; 5,559,169; 5,571,311; and 5,559,169 as well as U.S. patent application Ser. No. 08/572,525, all of which are hereby incorporated in their entireties by reference herein.
The particle having the attached vinyl substituted aromatic group or the vinyl substituted alkyl group is then reacted with a reactive free radical source and a stable free radical source for a sufficient time and at a sufficient temperature to form the modified particle having the attached group, like that of formula (I). The molar ratio of the reactive free radical source to the stable free radical source is from about 0.7 to about 2.0, and preferably from about 0.9 to about 1.1. Examples of the reactive free radical source include, but are not limited to, radicals generated from organic peroxides such as benzoyl peroxides and azo initiators such as azobisisobutyronitrile, and the like. The reactive free radical source is present in amounts sufficient to react with the vinyl aromatic group or vinyl alkyl group present on the particle. Preferably, the amount of the reactive radical source is from about 0.01 mmoles/g (of particle) to about 10 mmoles/g and more preferably from about 0.01 to about 5 mmoles/g.
Alternatively, the modified particles of the present invention can be made by first forming the groups of the formulas described above, such as formula (I). Preferably, the stable free radical group is attached in the meta or para position of the aromatic group, if one is used. The group having the aromatic group or alkyl group with the stable free radical group is then attached to the particle by a diazonium treatment in the manner described in the above referenced patents and patent applications, where a diazonium salt will first be formed containing a group of one of the formulas described above in the manner described in the above-referenced patents. The groups of the formulas can be then subsequently attached to the particle. In a less preferred way, the formulas of the present invention can be attached to the particle through a hydroxyl or carbonyl group present on the particle. Also, the modified particle of the present invention can be formed by attaching a stable free radical compound containing at least one alkoxy silyl, alkoxy titanyl, or alkoxy zirconyl group to the particle which, in this particular process is preferably a metal oxide or metal hydroxide, or a carbon surface. This particular embodiment would attach a group of formula (II) or (IV) to a particle.
In another process, the modified particle can be formed by first taking an aromatic group or an alkyl group and reacting it with a compound to form the groups of the formulas described above except for the presence of the xe2x80x94SFR group. In other words, a group having the formula Axe2x80x94R1xe2x80x94CR2R3 would first be formed and then the xe2x80x94SFR would be attached to this group to form a group of formula (I) of the present invention which can then be attached to the particle. In this process, R2 and R3 are preferably hydrogen.
A related process involves first taking an aromatic group or an alkyl group, such as a group having the formula Axe2x80x94R1xe2x80x94CR2R3 and attaching it onto the particle, for instance by a diazonium treatment in a manner described above, and then attaching the xe2x80x94SFR group to form a group of formula (I) of the present invention. Example 7 of the present application shows a specific embodiment of this process. In more detail, this process involves proton abstraction wherein a group containing an abstractable proton which leaves behind a carbon-centered radical is attached onto an aromatic group or an alkyl group, wherein the aromatic group or the alkyl group is directly attached to the particle. For purposes of this process, the aromatic group or the alkyl group can first be attached to the particle and then subsequently a group containing the abstractable proton can then be attached or an aromatic group or an alkyl group containing an abstractable proton can be attached onto the particle, for instance, by a diazonium treatment as described above. Then, a reactive free radical source and a stable free radical source are reacted with the particle having the attached aromatic group or alkyl group with the group containing an abstractable proton for a sufficient time and at a sufficient temperature to form the modified particle having the attached group, like that of formula (I). This modified particle having the attached group, like that of formula, (I) can then be subjected to polymerization reactions in order to have polymers attached thereto such as set forth in formula (III). In this process, the reactive free radical source abstracts the proton from the group containing the abstractable proton which thus leaves a carbon-centered radical behind which permits the stable free radical source to attached thereto to create the modified particles of the present invention such as set forth in formula (I). Examples of a group containing an abstractable proton which leaves behind a carbon-centered radical include alkyl groups, alkenes with a hydrogen atom in the alpha position to the olefinic bond, and the like. Specific examples include C1-C20 alkyl groups, such as methyl, ethyl, propyl, butyl, and the like. The reactive free radical source for this process can be organic peroxides such as benzoyl peroxides and t-butyl peroxides. Examples of the stable free radical source are described above and can be the same for this process. This process can also be applied where the modified particle aggregate has a group attached like that of formula (II) and (IV).
Alternatively, the process of making the modified particles of the present invention can be a three step process where the alkyl or aromatic group is first attached to the particle and then the group having the formula R1xe2x80x94Cxe2x80x94R2R3 can be attached to the aromatic group or alkyl group. Then in a third step, the xe2x80x94SFR can be attached to the R1xe2x80x94Cxe2x80x94R2R3 group.
Also, in making the modified particles having the attached group of one the formulas described above, an aliphatic vinyl group can be attached to the particle surface by a diazotisation of a vinyl substituted amino aromatic or alkyl compound, or a vinyl substituted alkoxy silyl, titanyl, or zirconyl derivative. The vinyl group is then reacted with an organic peroxide and a stable free radical such that the organic peroxide and stable free radical are present in an amount sufficient to react with at least one percent of the vinyl groups and preferably from about 50 to about 100% of the vinyl groups and the mole ratios of the organic peroxide to stable free radical are preferably from about 0.5:1 to about 1:1.
The modified particles of formula (II) can be made in the following manner. The aggregate comprising at least one carbon phase and at least one metal-containing species phase can be made as described in U.S. patent application Ser. No. 08/828,725, hereby incorporated herein by reference. The aggregate comprising at least one carbon phase and at least one metal containing species phase can be made as described in U.S. patent application Ser. No. 08/446,141 and 08/750,017. The aggregate or particle can then be reacted with a coupling agent by adding the coupling agent to the aggregate in a medium and mixing. Then, the aggregate or particle having the attached coupling group can be reacted with a reactive radical source and stable free radical source as described above.
For purposes of the above-described reactions, the reaction should occur for a time and temperature sufficient to form the attached group onto the particle or aggregate. Generally, this time is from about 3 minutes to about 96 hours and more preferably from about I hour to about 24 hours. The temperature of the reaction is dependent on the half-life of the peroxide, preferably from about 50xc2x0 C. to about 200xc2x0 C., and more preferably from about 75xc2x0 C. to about 125xc2x0 C.
For the various methods described above, any solvent, aqueous or non-aqueous, can be used. Preferably, the solvent does not interfere with the radical on the particle. Preferably, the solvent is toluene, benzene, or xylene. Mixtures of various solvents can be used as well.
With the modified particles described above, polymers can be attached onto these attached groups by reacting these modified particles or aggregates with one or more polymerizable monomer(s) such as a vinyl or diene containing monomer. Specific examples of Such monomers include, but are not limited to styrene, isoprene, butadiene, chloromethylstyrene, methyl methacrylate, and butyl methacrylate, as well as acrylic acid and esters of acrylic acid and methacrylic acid and esters of methacrylic acid. More specific monomer examples include, but are not limited to, hydroxyalkyl (meth)acrylates, such as hydroxyethyl (meth)acrylate, hydroxyproyl (meth)acrylate; alkyl (meth)acrylates such as methyl acrylate or butyl acrylate; glycidyl (meth)acrylate; dimethylaminoethylacrylate; 2-acryl trimethyl ethylammonium chloride; aminoethyl acrylate; acrylonitrile; vinyl acetate, and the like. Mixtures of two or more monomers can be also used and/or polymerized sequentially. For purposes of the present invention, the vinyl containing monomer includes vinyl containing monomers having additional olefinic groups which are conjugated or unconjugated to the vinyl containing monomer.
The polymerization reaction is conducted under conditions which permits the polymerization of the monomer so that it forms a part of the group attached onto the particle or aggregate. These conditions are preferably heating modified particles with a monomer above 80xc2x0 C., preferably from about 120xc2x0 C. to about 150xc2x0 C., optionally in the presence of a solvent. The reaction can be ended by lowering the temperature below 80xc2x0 C. The polymer-modified particle can then be subjected to distillation, steam stripping, or precipitation or other known methods in order to remove residual monomers and solvents.
The polymerization reaction thus can produce any length of polymer on the modified particle or aggregate. For example, polymers having average molecular weights, preferably ranging from about 500 to about 1,000,000 can be made. Other ranges of average molecular weights include, but are not limited to, from about 500 to about 3,000, and from about 500 to about 2,000, and from about 500 to about 500,000, and from about 1,000 to about 250,000. The polymers can be any type, such as homopolymers, co-polymers, ter-polymers, or higher chain polymers. The polymers can also be block, graft, or random-type polymers. The polymers can be branched or unbranched. Polymers, such as comb polymers, can be formed or located off of the main polymer chain, and these polymers can be any type of polymer. Specific examples include, but are limited to, polyamines, such as polyethyleneimine or polyalkylene oxides, grafted onto the main polymer chain. The polymers that are formed can be ionic (e.g., cationic or anionic) or non-ionic polymers. Specific examples of polymers include, but are limited to, polyamides, polyacrylics, polyvinylacetates, polyvinylalcohols, polyvinylpyridines, polyvinylpyrrilodones, polyvinylinidazoles, and acrylainides and derivatives thereof as well as combinations thereof.
Once the polymerization occurs, the modified particle will have a group attached having the formula:
wherein the substituents are the same as described earlier for formula (I) and X represents a polymer formed from at least one polymerizable vinyl or diene containing monomer.
Similarly, when the modified particle or aggregate having a group of formula (II) is polymerized by the introduction of one or more monomers, the group attached to the particle or aggregate will have the formula:
wherein the substituents are the same as described in formula (II) and X represents a polymer formed from at least one polymerizable vinyl or diene containing monomer.
In another embodiment, a modified particle has an organic group containing a xe2x80x94SFR group directly attached to the particle. Preferably, the xe2x80x94SFR group is directly attached to the particle. The xe2x80x94SFR group and particle can be the same as discussed above. This type of modified particle can be prepared by heating a particle, like carbon black, with a organic group comprising a stable free radical in a solvent, such as toluene and preferably, in an inert atmosphere. With this modified particle having an attached organic group having a xe2x80x94SFR group, polymers can be attached onto the xe2x80x94SFR group by reacting the modified particle with a polymerizable monomer as discussed above using the same procedure.
With any of the above-described groups containing the xe2x80x94SFR group, the modified particle or aggregate containing the xe2x80x94SFR group or the polymerized versions thereof can be terminated by any means known to those skilled in the art in view of the present application so that a terminated moiety (-T) is located in the position of the xe2x80x94SFR group in the formulas above. In particular, the xe2x80x94SFR group can be replaced with a proton (e.g., hydrogen atom), subjected to disproportionation, or replaced with a chemical group through group transfer and the like. For instance, the xe2x80x94SFR group can be replaced with a metal containing group (e.g., tin or tin compound), a hydroxy group, or a halide group. For purposes of the present invention, the terminated moiety includes any chemical group capable of forming a chemical bond by substitution or replacement of the xe2x80x94SFR group, by one or multiple steps. For instance, the hydroxy group or halide group replacing the xe2x80x94SFR group can then be subsequently modified or replaced with chemical groups, such as organic groups, by such means as conventional oxidation reactions known to those skilled in the art. This termination of removing the xe2x80x94SFR group and replacing it or terminating it with another group can be accomplished, for instance, by methods described in 214 ASC Nat""l Mtg, Las Vegas, Sep. 7-11, 1997, Paper in ORGN O61, Gravert, D. J.; Datta A.; Wentworth P., Jr.; Janda, K. D., which are incorporated in their entirety by reference herein.
The modified particles of the present invention, and preferably the polymerized and terminated versions of the modified particles of the present invention, can form part of a polymeric composition and be present with other ingredients commonly used and found in polymeric compositions.
The modified particle of the present invention can be used in a variety of applications. For instance, it can be used in coating formulations or compositions, ink formulations or compositions, or toner formulations or compositions, such as printing inks and inkjet inks, toners, automobile coatings, and the like. Also, the modified particles can be used as reinforcers for compositions, such as polymeric compositions and can also serve as impact modifiers, or as agents used to increase compatibility of a polymeric composition.
In more detail, reinforcement of elastomeric compositions including tire, hose, profile extrusion, seals, gaskets, and vibration isolation units, as well as the specific reinforcement of a single elastomer phase in a multiphase elastomer blend composition; reinforcement of thermoplastic compositions such as polyolefines, styrenic, acrylics, polyesters and polyamides, and thermoplastic elastomers and thermoplastic polyolefines; reinforcement of thermoset compositions, e.g., acrylics; impact modification of thermoplastic compositions; impact modification of thermosets; highly dispersible masterbatch for pigmentation, reinforcement, and/or UV protection of thermoplastic compositions, coatings, thermoplastic elastomers, and crosslinked compositions; as a synthetic support for solid phase organic synthesis; as a support or medium for effluent extraction processes - both organic and inorganic components; as a catalyst support; and/or as a superadsorbant for either aqueous of hydrocarbon materials, e.,q., use in sanitary wear, growing medium for plants.
The modified particles of the present invention can be incorporated in and form a part of elastomeric compositions. Other conventional ingredients for elastomeric compositions can also be present, such as coupling agents and the like.
Coupling agents, as used herein, include, but are not limited to, compounds that are capable of coupling fillers such as carbon black or silica to an elastomer having one functionality which will attach to the particle and another functionality which will attach to the elastomer. Coupling agents useful for coupling silica or carbon black to an elastomer, are expected to be useful with the silicon-treated carbon blacks. Useful coupling agents include, but are not limited to, silane coupling agents such as bis(3-triethoxysilylpropyl)tetrasulfane (Si-69), 3-thiocyanatopropyl-triethoxy silane (Si-264, from Degussa AG, Germany), xcex3-mercaptopropyl-trimethoxy silane (A189, from Union Carbide Corp., Danbury, Conn.); zirconate coupling agents, such as zirconiumin dineoalkanolatodi(3mercapto) propionato-O (NZ 66A, from Kenrich Petrochemicals, Inc., of Bayonne, N.J.); titanate coupling agents; nitro coupling agents such as N,Nxe2x80x2-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane (Sumifine 1162, from Sumimoto Chemical Co., Japan); polyalkoxysiloxane (e.g. Zeruma from the Yokohama Rubber Co. Ltd., Japan) and mixtures of any of the foregoing. The coupling agents may be provided as a mixture with a suitable carrier, for example X50-S which is a mixture of Si-69 and N330 carbon black, available from Degussa AG.
The elastomeric compounds of the present invention may be prepared from the modified particles of the present invention by compounding with any elastomer including those useful for compounding a carbon black.
Any suitable elastomer may be compounded with the modified particles to provide the elastomeric compounds of the present invention. Such elastomers include, but are not limited to, homo- or co-polymers of 1,3 butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, and propylene. Preferably, the elastomer has a glass transition temperature (Tg) as measured by differential scanning colorimetry (DSC) ranging from about xe2x88x92120xc2x0 C. to about 0xc2x0 C. Examples include, but are not limited, styrene-butadiene rubber (SBR), natural rubber, polybutadiene, polyisoprene, and their oil-extended derivatives. Blends of any of the foregoing may also be used.
Among the rubbers suitable for use with the present invention are natural rubber and its derivatives, such as chlorinated rubber and epoxidized rubber. The modified particles of the present invention may also be used with synthetic rubbers such as: copolymers of from about 10 to about 70 percent by weight of styrene and from about 90 to about 30 percent by weight of butadiene such as copolymer of 19 parts styrene and 81 parts butadiene, a copolymer of 30 parts styrene and 70 parts butadiene, a copolymer of 43 parts styrene and 57 parts butadiene and a copolymer of 50 parts styrene and 50 parts butadiene; polymers and copolymers of conjugated dienes such as polybutadiene, polyisoprene, polychloroprene, and the like, and copolymers of such conjugated dienes with an ethylenic group-containing monomer copolymerizable therewith such as styrene, methyl styrene, chloromethylstyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl 2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine, alkyl-substituted acrylates or methacrylates, vinyl ketone, methyl isopropenyl ketone, methyl vinyl ether, alpha-methylene carboxylic acids and the esters and amides thereof such as acrylic acid, methacrylic acid, and dialkylacrylic acid amide; also suitable for use herein are copolymers of ethylene and other high alpha olefins such as propylene, butene, pentene, hexene, and octene. Other monomers that could be used include norbornene and hex-1,5-diene, and the like.
The rubber compositions of the present invention can therefore contain one or more elastomers, curing agents, reinforcing fillers, coupling agents, and, optionally, various processing aids, oil extenders, and antidegradents. In addition to the examples mentioned above, the elastomer can be, but is not limited to, polymers (e.g., homopolymers, copolymers, and terpolymers) manufactured from 1,3 butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, propylene, and the like. It is preferred that these elastomers have a glass transition point (Tg), as measured by DSC, between xe2x88x92120xc2x0 C. and 0xc2x0 C. Examples of such elastomers include poly(butadiene), poly(styrene-co-butadiene), and poly(isoprene).
Elastomeric compositions disclosed in the present invention include, but are not limited to, vulcanized compositions (VR), thermoplastic vulcanizates (TPV), thermoplastic elastomers (TPE) and thermoplastic polyolefins (TPO). TPV, TPE, and TPO materials are further classified by their ability to be extruded and molded several times without loss of performance characteristics.
The elastomeric compositions may include one or more curing agents such as, for example, sulfur, sulfur donors, activators, accelerators, peroxides, and other systems used to effect vulcanization of the elastomer composition.
The resultant elastomeric compounds containing the aggregates of the present invention and optionally containing one or more coupling agents may be used for various elastomeric products such as a tread compound, undertread compound, sidewall compound, wire skim compound, innerliner compound, bead, apex, any compound used in carcass and other components for vehicle tires, industrial rubber products, seals, timing belts, power transmission belting, and other rubber goods.
In an embodiment of the present invention, the elastomeric compositions of the present invention, which contain at least one modified particle of the present invention, can have a total residue after nitrogen pyrolysis at 650xc2x0 C. of from about 1% to about 60% by weight.
For purposes of the present invention, the ink includes at least one type of polymerized-terminated modified particle, and at least one ink vehicle. The inkjet ink formulation includes at least one type of polymerized terminated modified particle, and at least one inkjet ink vehicle. Generally, the formulations described in WO 97/47699 with respect to coatings and inks can be used herein, however, incorporating the modified particles of the present invention. The coating formulations contain at least one type of polymerized-terminated modified particle and at least one suitable solvent. Other conventional additives may be incorporated into the coating formulations, such as a binder.
Each of these formulations can contain additional conventional colorants and other optional, conventional ingredients or additives, for instance as described in U.S. Pat. Nos. 5,571,311; 5,672,198; 5,266,361; 5,707,432 such as a humectant, binders, dyes, biocides, surfacants, penetrants. All of these patents are incorporated herein in their entirety by reference herein.
The toner can contain at least one polymerized-terminated modified particle and resin particles.
The conventional and standard ingredients or additives for toner formulations, such as those described in U.S. Pat. Nos. 5,278,018; 5,275,900; 5,695,899 and 5,116,712, can be used in the present invention, and are incorporated in their entirety by reference herein. The toner can be a positively or negatively charged toner composition.
In the various products incorporating the modified particles of the present invention, one or more types of other particles can also be present, such as a carbon product (e.g., carbon black), metal oxide (e.g., silica, zinc oxide, and aluminum oxide), metal silicate (e.g., clay, aluminum, calcium, magnesium silicates), modified silica, modified carbon products having an attached organic group, an aggregate comprising at least one carbon phase and at least one silicon-containing species phase optionally having an attached organic group, carbon black at least partially coated with silica, or any combination thereof. In any product mentioned herein, more than one type of modified particle of the present invention can be present in the various products described above.


Many types of electrical equipment contain IC (integrated circuit) devices which are vulnerable to damage from high voltage transients.
In a television receiver the anode of the image producing kinescope is typically biased at a high potential, e.g., 25,000 volts. High voltage transients may be produced when the high voltage anode of the kinescope is rapidly discharged to points at lower potentials. Such high voltage transients have positive and negative peaks often in excess of 100 volts and may last several microseconds. High voltage transients may also be produced when electrostatic charges are discharged as a user contacts the controls of the television receiver. High voltage transients may be coupled to the terminals of IC's employed in the television receiver for video and audio signal processing. Accordingly, these IC's may be damaged by high voltage transients.
Copending patent application entitled "Protection Circuit for Integrated Circuit Devices," Ser. No. 212,534, filed in the name of the present inventor Dec. 3, 1980 and assigned to RCA Corporation, discloses a protection device for protecting an IC from negative voltage transients that exceed the most negative power supply potential applied to the IC. Another copending patent application entitled "Protection Circuit for Integrated Circuit Devices," Ser. No. 230,357 filed also in the name of the present inventor Jan. 30, 1981, and also assigned to RCA Corporation, discloses a protection circuit which is triggered at one forward biased diode voltage drop above the positive supply voltage for protecting an IC from positive voltage transients that exceed the most positive power supply potential applied to the IC.
However, in a television receiver, particular signals applied to an IC may have positive voltage excursions which in normal operation exceed the positive supply potential. For example, a typical television horizontal/vertical regulator IC requires a feedback connection from the kinescope deflection coils to one of its input terminals. While the power supply for the IC is typically +10 volts, the peak feedback voltage from the deflection coils is typically +27 volts. Therefore, it is desirable to provide a positive transient protection circuit for such IC's that permits normal signal voltages to exceed the power supply potential without activating such protection circuit and nevertheless protects the IC from excessively large transients.


1. Field of the Invention
The present invention relates to the field of electronic design automation systems for designing and characterizing integrated circuits. More specifically, the present invention relates to an evaluation system for evaluating a technology library for transformation into an effective modeling method and data structure for modeling signal propagation delay of a timing arc of an integrated circuit cell.
2. Related Art
The rapid growth of the complexity of modern electronic circuits has forced electronic circuit designers to rely upon computer programs to assist and automate most steps of the circuit design process. Typical circuits today contain hundreds of thousands or millions of individual pieces or xe2x80x9ccells.xe2x80x9d Such a design is much too large for a circuit designer or even an engineering team of designers to manage effectively manually. To automate the circuit design and fabrication of integrated circuit devices, electronic design automation (EDA) systems have been developed.
An EDA system is a computer software system designers use for designing integrated circuit (IC) devices. The EDA system typically receives one or more high level behavioral descriptions of an IC device (e.g., in HDL languages like VHDL, Verilog, etc.) and translates this high level design language description into netlists of various levels of abstraction. At a higher level of abstraction, a generic netlist is typically produced based on technology independent primitives. The generic netlist can be translated by the EDA system into a lower level technology-specific netlist based on a technology-specific library that has gate-specific models for timing and power estimation. A netlist describes the IC design and is composed of nodes (elements) and edges, e.g., connections between nodes, and can be represented using a directed cyclic graph structure having nodes which are connected to each other with signal lines. The netlist is typically stored in computer readable media within the EDA system and processed and verified using many well known techniques. One result is a physical device layout in mask form which can be used to directly implement structures in silicon to realize the physical IC device.
More specifically, within a typical EDA system, the circuit designer first produces a high-level description of the circuit in a hardware description language such as Verilog or VHDL. This high-level description is converted into a netlist using a computer implemented synthesis process such as the xe2x80x9cDesign Compilerxe2x80x9d by Synopsys of Mountain View, Calif. A netlist is a description of the electronic circuit which specifies what cells compose the circuit and which pins of which cells are to be connected together using wires (xe2x80x9cnetsxe2x80x9d). Importantly, the netlist does not specify where on a circuit board or silicon chip the cells are placed or where the wires run which connect them together. Determining this geometric information is the function of a computer controlled placement process and a computer controlled routing process.
The placement process finds a location for each cell on a circuit board or silicon chip. The locations are specified, typically, in two dimensional spatial coordinates, e.g., (x, y) coordinates, on the circuit board or silicon chip. The locations are typically selected to optimize certain objectives such as wire length, wire routibility, circuit speed, circuit power consumption, and/or other criteria, subject to the condition that the cells are spread evenly over the circuit board or silicon chip and that the cells do not overlap with each other. The output of the automatic computer controlled cell placement process includes a data structure including the (x, y) location for each cell of the IC design.
Next, the designer supplies the netlist and the cell location data structure, generated by the placement program, to a computer implemented automatic wire routing process (xe2x80x9crouterxe2x80x9d). The router generates wire geometry within data structure for connecting pins together. The wire geometry data structure and cell placement data structure together are used to make the final geometric database needed for fabrication of the circuit. Routers typically include a coarse routing process and a fine routing process. The coarse router provides a general path for the routing that is done at the detail stage. The coarse router examines at the level of the whole integrated circuit chip and its available resources and determines what the rough pathways should be from a topological standpoint. The fine or detail router lays down the actual geometries and connected wire segments in the appropriate layers as a wire connection may span multiple layers. The fine router creates wire routes that are xe2x80x9cclean,xe2x80x9d e.g., do not have design rule violations, do not overlap other structures and can be fabricated.
The signal propagation delay (xe2x80x9ccell delayxe2x80x9d) through a cell (xe2x80x9cgatexe2x80x9d) is an important characteristic to model within an EDA system. The cell delays in a technology library are typically represented using non-linear delay models (NLDM) which are essentially look-up tables. Typically, a group of tables are supplied in the technology library for each cell, tables are designated for representing the rise and fall delays for each timing arc of the cell. These tables are typically 4-dimensional in that they accept output load and input transition time (slew) as inputs and generate delay and output slew values as outputs. These output load-based NLDMs, while providing delay values, have a disadvantage in the cell delay modeling processes that are performed early in the circuit synthesis process. For instance, during early circuit synthesis processes, the output load of the cell is not known because the cells have not yet been mapped to the target technology library and, as such, the cells are not yet connected together. Output load estimates are made in these early synthesis processes because the output load-based NLDMs need these values as inputs. Unfortunately, the output load estimates introduce inaccuracies in the overall circuit synthesis process. The output load-based NLDMs also introduce a xe2x80x9cCatch-22xe2x80x9d problem in that delay modeling helps to accurately map the cells, but mapping yields the true output capacitance that is then used to accurately determine the cell""s delay, etc. It would be advantageous to provide a cell delay modeling system that did not require the output load of a cell as an input.
A more simplistic linear delay model has been proposed as a vehicle for efficient logic synthesis of high-performance designs. This delay model is also referred to as the constant delay model. In the constant delay model, the delay of a timing arc of a gate, xcfx84, is represented as:
xcfx84=Rxe2x80xa2Co+p
where R=output resistance,
Co=output load of the timing arc output, and
p=intrinsic delay of a gate.
This relationship can also be represented as:
xcfx84=(Rxe2x80xa2Ci)xe2x80xa2(Co/Ci)+p
where Ci=input capacitance of the timing arc input.
The term (Rxe2x80xa2Ci) is also referred to as the logical effort of the gate. The term (Co/Ci) is also referred to as the electrical effort or gain of the gate.
The constant delay model assumes that the delay of the timing arc remains constant. The reasoning for this is as follows. The intrinsic delay of the gate, p, is constant. As Co increases, the gate is implicitly upsized, so Ci increases appropriately. So, (Co/Ci) remains constant. As Ci increases, R appropriately decreases, so (Rxe2x80xa2Ci) remains constant. Consequently, xcfx84 remains constant. An important property of the constant delay model is that the delay of a timing arc is independent of load, e.g., the delay does not depend on either Co or Ci, but merely on the ratio of the two. This property is useful in early stages of logic synthesis, prior to technology dependent optimization because the actual load of a gate is unknown at that time.
However, while this simplistic delay model does have its advantages, the constant delay model does not consider several important factors when modeling the delay of a gate. For instance, the constant delay model does not consider the impact of transition times on delay, nor does it deal effectively with complex gates with different input capacitances for different input pins. The model also fails to take into consideration the impact of limited discrete sizes in the technology library nor of certain design rules like maximum capacitance and maximum transition associated with gates. By not taking into consideration the above factors, the constant delay model is not as accurate as non-linear delay models. It would be advantageous to provide a method and system for providing cell delay modeling that offered the advantageous of constant cell delay modeling but also considered the above referenced factors.
A number of technology libraries currently exist that utilize output load-based non-linear delay models (NLDMs). It would be advantageous to provide a mechanism that automatically constructed a technology library that includes output load-based NLDMs and could also be transformed into an alternate library format that used delay models that do not require output load as an input, thereby alleviating the above problems. If such a library construction process or system existed, vendors of technology libraries could readily construct technology libraries can be used with converters to the alternate library format.
A system and computer implemented process are described herein for constructing a technology library that is suitable for use with an electronic design automation system that converts the target technology library into a scalable cell library having non-linear, gain-based delay models for estimating circuit delay. The scalable cell library can then be used by gain-based structuring and mapping processes. In one embodiment, the library construction process places at least six discrete cells in each logic function of a basic cell set. The library construction process also places at least five discrete cells in each logic function of an extended cell set and rules out cell sizing using buffer circuits. Also, for each discrete cell in the complete cell set, the variance of the capacitances between different input pins of the cell is maintained to be within 10 percent. For corresponding timing arcs of discrete sizes for a particular logic function, the present invention keeps the delay of the corresponding timing arcs within 10 percent of each other, when the ratio of the output load to input capacitance are equal for the corresponding input-output pin paris. Also, the present invention constructs a technology library that has geometrically distributed sizes of cells within each logic function. Lastly, for each discrete cell within a logic cluster, the output maximum capacitance constraint is kept linearly proportional to the average input capacitance of the discrete cell. These processes likely allow a technology library to be suitable for the generation of a scalable library which can be used for integrated circuit design and fabrications.
Embodiments of the present invention also include a library evaluation system for determining the suitability of a target technology library for generating a suitable scalable library that utilizes delay models that are gain-based. Other embodiments of the present invention provides a cell delay modeling system and method for modeling cell delay without requiring the output load capacitance of the cell as an input. Furthermore, the present invention provides a non-linear delay model for accurate cell delay modeling. The present invention provides a cell delay modeling system and method that considers the impact of transition times on delay, that deals effectively with complex gates with different input capacitances for different input pins, that takes into consideration the impact of limited discrete sizes in the technology library and furthermore takes into consideration certain design rules like maximum capacitance and maximum transition associated with gates. These and other advantages of the present invention not specifically mentioned above will become clear within discussions of the present invention presented herein.
An evaluation system is described for evaluating the suitability of a target technology library for use with an electronic design automation system that converts the target technology library into a scalable library having non-linear, gain-based delay models for estimating circuit delay. After a library analysis process executes, an internal scalable library is generated having a scalable cell model for each functional cell class of the target technology library. Internal characteristics of the scalable library are analyzed to determine whether or not the target technology library is suitable for generating a suitable scalable library. Suitable scalable libraries are used for gain-based structuring and mapping processes. The library evaluation processes uses several metrics to determine the suitability of the target technology library. The first metric is the number of sizes metric and the second metric is the size consistency metric. The number of sizes metric is computed with respect to subsets (e.g., basic set and extended set) of the scalable cells identified within the scalable library. The number of sizes metric determines whether or not there are sufficient numbers of discrete cells within the cell clusters of the subsets. The size consistency metric examines the input pin capacitance ratios and the delay error amounts for discrete cells of the scalable library. An evaluation report is then compiled using the above metric information to grade library suitability.
In another embodiment, a non-linear, gain-based modeling of circuit delay within an electronic design automation (EDA) system is described herein. The present invention provides a scalable cell model for use in logic structuring and mapping for the design of integrated circuits. The scalable cell model provides a four dimensional non-linear delay model that accepts (1) input slew and (2) gain and provides (3) delay and (4) output slew information for a scalable cell. By eliminating output loading as a requirement for delay computations, the scalable model of the present invention can effectively be used to provide accurate delay (timing) information for those logic synthesis processes that precede technology based optimizations where the actual load of a cell is unknown. This scalable cell model considers: the impact of transition times on delay; complex gates having different input capacitances for different input pins; the impact of limited discrete cell sizes in the technology library; and design rules, e.g., maximum capacitance and maximum transition associated with gates.
A library analysis process creates a scalable technology library by analyzing discrete cells from a target technology library. The target technology library is analyzed and clustering is performed to select a cluster (e.g., subset) of cells for each cell group sharing a common functionality. Clustering is performed based on a cluster metric that can be any of the following: a delay consistency metric, an input pin consistency metric, an intercept/slope consistency metric or an consistency metric based on the slope and average input capacitance being inversely proportional. A nominal input slew value is computed for all cells and a scaling factor is also computed for each cell of each cell cluster. From each cell cluster, a four dimensional scalable cell model (look-up table) is then generated that inputs gain and input slew and outputs delay and output slew. Separate non-linear delay models are provided for rise and fall time for each cell. Those cells not within a cell cluster do not participate in generating data for the scalable model. Therefore, the scalable cells in the scalable library are characterized with a new load-independent delay model, in which delay is modeled as a non-linear function of gain and slew.
A default gain is then computed for each scalable cell model and an area model and an input pin capacitance model are then generated for each scalable cell model. The input pin capacitance model is useful for load propagation of the scalable cells. For a particular integrated circuit design, its designated discrete cells are replaced with the scalable cells which are used during logic structuring and mapping. Logic structuring and mapping processes use the scalable cells as a basis for the optimization. After synthesis, a discretization process then converts the scalable cells back to discrete cells before the technology dependent optimizations are performed. Therefore, at the end of optimization, present invention discretizes the scalable cells to the closest discrete cells available in the target technology library. Following this, technology based optimization is performed primarily for delay, design rule fixing and area recovery. The accuracy of the logic structuring and mapping processes is hinged upon the accuracy of the scalable model that library analysis derives.
The present invention also has a capability of automatically determining whether a technology library is suitable for its optimization techniques. This is important because the accuracy of many processes in the present invention may depend on the accuracy of the gain-based scalable delay model that is created. After performing library analysis, a library evaluation step is performed to determine if the target technology library is suitable. If the library is found to be suitable, logic structuring and mapping is invoked and if not, a conventional optimization engine can be used.


1. Technical Field
The invention relates to reinforced resilient pneumatic tires and more particularly to a vehicle tire reinforced by a thin annular composite band which is stabilized by a plurality of radial elements in the tire sidewalls to enable the tire to run in an unpressurized condition. More particularly, the invention relates to a pneumatic tire in which the band element is formed by a plurality of helically wound layers of material strips, in which at least the outer strips are prestressed in tension to improve the endurance of the band and minimize band stresses placed thereon during both pressurized and unpressurized conditions.
2. Background Information
Various tire constructions have been devised over the years which enable a tire to run in an under-inflated or non-inflated condition such as after receiving a puncture and loss of pressurized air for extended periods of time and at relatively high speeds. This enables the vehicle operator to safely drive the vehicle to an appropriate location for repair or replacement of the punctured tire. Certain of these safety tires, referred to as "run flat tires", have been successful for certain applications and certain types of tire constructions. Most of these run flat tires achieve their run flat capability, by the placement of reinforcing layers or members of relatively stiff elastomeric material in the side walls of the tire which enable the tire to support the vehicle weight even with the complete loss of internal air pressure. Examples of such prior art run flat tire constructions which use such sidewall inserts are shown in U.S. Pat. Nos. 3,911,987; 3,949,798; 3,954,131; 4,067,372; 4,202,393; 4,203,481; 4,261,405; 4,265,288; 4,287,924; 4,365,659; 4,917,164; and 4,929,684.
In addition to these prior art run flat tire patents, various run flat tire constructions have been developed which utilize a thin annular band which extends circumferentially throughout the tire beneath the tread area. Examples of such banded run flat tires are shown in the following patents.
U.S. Pat. No. 4,428,411 describes a method to make a particular band for use in a run flat tire which uses a series of side-by-side elements in the form a helix. The band has hoop compression as against a conventional breaker belt that has no significant compressive strength but is used only to resist tension loads endured by the tire when pressurized. However, the band has no residual stresses after manufacture which reduces the critical operational stresses after integration into a tire as is the band of the present invention.
U.S. Pat. Nos. 4,673,014 and 4,794,966 teach a method to acquire desirable prestressing in a fabricated band made of helical elements. Physically bending the larger diameter helix element around a smaller mandrel and securing it with a resin impregnated tape does acquire a desirable level of prestressing. However, the band of the present invention is achieved by inherent thermal shrinkage as the sequentially overlapped material layers eliminate any physical bending of a structural element as is required in the method of these two patents.
U.S. Pat. No. 4,456,048 teaches a method of acquiring a change in band stiffness as a function of deflection. The band has a lower stiffness for normal pressurized operation and has a higher stiffness to support load when the tire is uninflated and experiences larger deflection. The band of the present invention does not have a variable stiffness but is prestressed and does not change the band stiffness. The band does favorably affect the range of operating stresses. Japanese Patent application No. JP 63141809 discloses a run flat tire having a banded element which is formed of layered strips of materials, such as an aramide filament which is impregnated with a high elasticity epoxy resin, which after hardening provides a stiffened band but provides no suggestion for prestressing a band in tension which is achieved during the manufacture of the band of the present invention. Thus the tire of this disclosure requires that elastomeric side wall inserts be utilized in combination with the band in order to achieve the desired run flat characteristics.
Other run flat banded pneumatic tires are shown in U.S. Pat. Nos. 4,111,249; 4,318,434; 4,428,411; 4,459,167; and 4,734,144.
Banded tires have been fabricated with band materials made of steel, aluminum, titanium, and epoxy and thermoplastic composites with glass, KEVLAR (aromatic polyamide) and graphite fiber reinforcement. The common failure mode with the light, economical laminate band construction is interlaminar shear within the band's primary bending neutral axis. This is a fatigue failure and is directly related to the spectrum of cyclic operating stress. As in all fatigue failures, the lower the stress, the longer the operating life.
Prestressing techniques lower the critical operating stress. This critical operating stress occurs in the footprint of the tire and is induced by road surface irregularities, aggravated by ride dynamics. This feature was identified by operating loaded tires on dynometer wheels and then compared with actual road tests. Dynometer tests showed an increase in cyclic life by a factor of 10-20 times. Thus, anomalies in the road surface can greatly shorten tire life when compared to dynometer testing.
There are three recognized approaches to improve the interlaminar fatigue life of the bands: lower the critical operating stress, improve the toughness features of the matrix and the introduction of reinforcing fibers thru the failure plane. This latter approach uses a weaving process and is applicable to wet or preimpregnated fiber tows or thermoplastic tape.
The proposed approach of the present invention uses a prestressing technique to reduce the critical operating stresses. The unique feature identified in this approach is that of beneficial residual stresses are introduced in the band by the fabrication process. The sequential application of reinforced thermoplastic tapes employing heat and high pressure to the contacting surfaces results in a gradual buildup of residual stress. The geometric features of the invention retain the desired strength of the reinforcing fiber in the hoop direction and provide adequate lateral strength, with the level of beneficial residual stress being achieved in the preferred embodiment with a winding angle preferably of .+-.15.degree.-20.degree. off circumferential.


This invention relates generally to integrated circuit devices made up of more than one die.
In a number of integrated circuit applications, relatively complex functions may be involved. Thus, in some cases, the capabilities desired to be integrated into a single integrated circuit die may exceed the available processing capabilities. Some functionalities are placed on one die and other functionalities are placed on another die.
The packaged dies may then be coupled together, for example by securing them to printed circuit boards having metallic interconnections to connect signals travelling between the two dies. This has the disadvantage that the footprint or size of the combined integrated circuit device is increased because spacing is needed between the dies to allow the desired interconnections. In addition, the resulting device may be slower due to the impedances arising from the metallic interconnections and the contacts to each die.
Thus, there is a continuing need for techniques for providing advanced functions in compact, multiple die integrated circuits.


A common construction of a header for an agricultural implement includes either a cutter bar with a pickup reel and/or a rotating tine pickup belt for feeding material to an auger which collects the material into a rear discharge of the header. In certain types of crops, material can be thrown upward onto the frame of the header above the rear discharge opening. The material can then obstruct the view of the operator of the implement, or become entangled in the implement, or be wasted by being thrown onto the ground instead of being collected in the usual manner of the implement.


A conventional rotation angle detection apparatus for detecting a rotation angle of a detected object includes a magnetism generation section, such as a magnet, and a magnetic flux density detection section, such as a Hall element. One of the magnetism generation section and the magnetic flux density detection section is attached to the detected object. The magnetic flux density detection section detects a magnetism of the magnetism generation section when the detected object rotates, thereby detecting the rotation angle of the detected object. For example, JP-A-2002-206911 discloses a rotation angle detection apparatus that includes a magnet as a magnetism generation section, a magnetic flux density sensor as a magnetic flux density detection section, and a signal processor as a processing section. The signal processor executes a correction operation. The signal processor corrects actual output voltages, which are based on an output signals of the magnetic flux density sensor, on the basis of predetermined values (voltage level) corresponding to predetermined correction points. The predetermined correction points are set at regular intervals.
In cases where the intervals of the correction points are constant, a nonlinearity of the output signal is not improved, and an error in the actual output voltages remains as a linearity error in the rotation angle. JP-A-2007-71889 discloses a correction method that divides a region where an output change rate is large more finely than a region where the output change rate is small. Japanese Patent No. 3,491,577 (corresponding to U.S. Pat. No. 6,498,479) discloses a correction method in which output signals of a magnetism detection element are converted into digital signals, and the digital signal are processed with an arcsine function. However, when an output waveform is unclear, the correction methods disclosed in JP-A-2007-71889 and Japanese Patent No. 3,491,577 cannot be used.