This invention is based upon the discovery that a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur can be used to improved the force ductility, elastic recovery, toughness and tenacity of asphalt cement. The polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur also exhibits excellent compatibility with asphalt. The repeat units in the polydiene rubber that are derived from sulfur are in the backbone of the polymer. These repeat units that are derived from sulfur typically contain from 2 to 8 sulfur atoms (xe2x80x94Snxe2x80x94). The subject invention more specifically relates to a modified asphalt cement which is comprised of (i) from about 90 weight percent to about 99 weight percent asphalt; (ii) from about 1 weight percent to about 10 weight percent of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur. The present invention also reveals an asphalt concrete which is comprised of (A) from about 90 weight percent to about 99 weight percent of an aggregate and (B) from about 1 weight percent to about 10 weight percent of a modified asphalt cement which is comprised of (i) from about 90 weight percent to about 99 weight percent asphalt; (ii) from about 1 weight percent to about 10 weight percent of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur. The present invention also discloses a process for preparing a modified asphalt cement which comprises (1) blending from about 1 to about 10 parts by weight of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur into from about 90 to about 99 parts by weight of asphalt at a temperature which is within the range of about 130xc2x0 to about 230xc2x0 C. to produce a polymer-asphalt blend; and (2) mixing from about 0.1 to about 3 parts by weight of sulfur into the polymer-asphalt blend to produce the modified asphalt cement.

Since the days of the Roman Empire importance of a good transportation system that includes roads and highways has been appreciated. By about 300 B.C., the first section of the Appian Way extending from Rome to Capua was built. Some of the more than 50,000 miles of roadway ultimately built in the Roman Empire was constructed with heavy stone. However, not much progress was made in the art of road construction from the era of the Roman Empire until the development of the motor vehicles, such as automobiles and trucks.
For centuries, stone blocks, wood blocks, vitrified brick and natural asphalt (bitumen) have been used to pave roads and highways. However, at the beginning of the automobile era, most rural roadway surfacing consisted of broken stone or gravel. Such roads were often rough, dusty and clearly inadequate for modern automobile and truck traffic.
Today, the United States has the most extensive highway system in the world with about 2,000,000 miles of paved road. Napoleon realized the importance of roadway systems and built such a system in France which today has the second most extensive system of paved roadways in the world covering about 500,000 miles. Germany, Japan, Great Britain, India and Australia also currently have systems of paved roads that extend well over 100,000 miles. In addition to these public roadways, there are countless paved driveways, parking lots, airport runways, and taxiways all over the world.
Today, roads, highways, driveways and parking lots are often paved with asphalt concrete. Pavement can be made with asphalt concrete that is dust-free, smooth and which offers the strength required for modem automobile and heavy truck traffic. Asphalt concrete is generally made by mixing aggregate (sand and gravel or crushed stone) with the proper quantity of asphalt cement at an elevated temperature. The hot asphalt concrete is then placed by a layering machine or paver on the surface being paved and thoroughly rolled before the asphalt concrete mixture cools. The asphalt concrete is normally applied at a thickness varying from about 25 to about 100 millimeters.
Asphalt concrete pavements can be made to be very smooth which offers outstanding frictional resistance for vehicles operating thereon. Such asphalt concrete pavement can also be repaired simply by adding additional hot asphalt concrete to holes and other types of defects which develop in the surface. Asphalt concrete pavements can also be upgraded easily by adding additional layers of hot asphalt concrete to old surfaces which are in need of repair.
Even though asphalt concrete offers numerous benefits as a paving material, its use is not trouble-free. One major problem encountered with asphalt concrete pavements is the loss of the adhesive bond between the aggregate surface and the asphalt cement. This breaking of the adhesive bond between the asphalt cement and the aggregate surface is known as xe2x80x9cstripping.xe2x80x9d The stripping of asphalt binder from aggregate surfaces results in shorter pavement life and many millions of dollars of maintenance work on American highways each year. Reduction of this stripping tendency is of great benefit for improving the condition of roads and lowering road maintenance costs.
Over the years, various methods have been developed to reduce stripping tendencies. For instance, amines and lime are known to act as anti-stripping agents and are frequently applied to the surface of the aggregate prior to mixing it with the asphalt cement in making asphalt concrete. U.S. Pat. No. 5,219,901 discloses a technique for reducing stripping tendencies which involves coating the aggregate with a thin, continuous film of a water-insoluble high molecular weight organic polymer, such as an acrylic polymer or a styrene-acrylic polymer.
U.S. Pat. No. 5,262,240 discloses a technique for providing aggregate with a high level of resistance to stripping by water, which comprises: (1) mixing the aggregate with latex to form a latex/aggregate mixture which is comprised of from about 0.005 weight percent to about 0.5 weight percent dry polymer; (2) heating the latex/aggregate mixture to a temperature which is within the range of about 66xc2x0 C. to about 232xc2x0 C.; (3) maintaining the latex/aggregate mixture at said elevated temperature for a time which is sufficient to reduce the moisture content of the latex/aggregate mixture below about 0.7 weight percent and to allow the polymer in the latex to crosslink on the surface of the aggregate to produce the coated aggregate.
At high service temperatures, such as those experienced on hot summer days, asphalt concrete can experience rutting and shoving. On the other hand, at low service temperatures, such as those experienced during cold winter nights, asphalt concrete can also experience low temperature cracking. To combat these problems, it is known in the art to modify asphalt cements with rubbery polymers, such as styrene-butadiene rubber (SBR). In some approaches, the SBR is added to the asphalt as a dry rubber while in others it is added as a latex. Such modification techniques can greatly improve resistance to rutting, shoving and low temperature cracking. However, the rubbery polymers used in such applications have a tendency to phase separate from hot asphalt cements due to poor compatibility. A solution to the problem of poor compatibility is offered by the technique disclosed in U.S. Pat. No. 5,002,987.
U.S. Pat. No. 5,002,987 relates to a modified asphalt cement containing from about 90 to about 99 parts by dry weight of an asphalt cement and from about 1 to about 10 parts by dry weight of a rubber latex having a weight average molecular weight of less than 250,000 and a Mooney viscosity of less than 50. The latex is a random polymer comprising from about 60 to 100 weight percent of at least one conjugated diolefin containing from 4 to 6 carbon atoms and from about 0 to 40 weight percent styrene. This latex polymer is highly compatible with the asphalt and provides good ductility that results in good resistance to low temperature cracking. However, the utilization of the rubbery polymers described in U.S. Pat. No. 5,002,987 in asphalt cements provide little improvement in elastic recovery or toughness. Thus, their use results in compromised rutting and shoving characteristics. There accordingly is a current need for a modifier which is compatible with asphalt cement and which improves the resistance of asphalt concrete made therewith to rutting, shoving and low temperature cracking.
U.S. Pat. No. 5,534,568 reveals an asphalt concrete which is comprised of (A) from about 90 weight percent to about 99 weight percent of an aggregate and (B) from about 1 weight percent to about 10 weight percent of a modified asphalt cement which is comprised of (1) from about 90 weight percent to about 99 weight percent of) asphalt and (2) from about 1 weight percent to about 10 weight percent of a rubbery polymer which is comprised of repeat units which are derived from (a) about 64 weight percent to about 84.9 weight percent of a conjugated diolefin monomer, (b) about 15 weight percent to about 33 weight percent of a vinyl aromatic monomer and (c) about 0.1 weight percent to about 3 weight percent of isobutoxymethyl acrylamide.
U.S. Pat. No. 4,145,322 discloses a process for making a bitumen-polymer composition which consists of contacting with each other, at a temperature between 130xc2x0 C. and 230xc2x0 C., 80 to 98 weight percent of a bitumen exhibiting a penetration value between 30 and 220, and 2 to 20 weight percent of a block copolymer, with an average molecular weight between 30,000 and 330,000 having the theoretical formula Sxxe2x80x94By in which S corresponds to the styrene structure groups, B corresponds to the conjugated diene structure groups, and x and y are integers, stirring the obtained mixture for at least two hours, then adding 0.1 to 3 percent by weight of elemental sulfur with respect to the bitumen and maintaining the mixture thus obtained under agitation for at least 20 minutes.
Batch polymerization techniques are normally used in synthesizing block copolymers that are utilized in modifying asphalt in order to attain desired performance characteristics. However, it is highly desirable from a cost standpoint to synthesize such polymers by utilizing continuous polymerization techniques. It would also be highly desirable to increase the force ductility, elastic recovery, toughness and tenacity of asphalt which is modified with such polymers. U.S. Pat. No. 5,986,010 discloses a technique for synthesizing, by a continuous polymerization process, a styrene-butadiene polymer which is highly suitable for modifying asphalt to improve force ductility, elastic recovery, toughness and tenacity.
U.S. Pat. No. 5,986,010 specifically discloses a process for synthesizing a styrene-butadiene polymer which is particularly useful for modifying asphalt by a continuous polymerization process, said process comprising the steps of: (1) continuously charging 1,3-butadiene monomer, an organo lithium compound, a polar modifier and an organic solvent into a first polymerization zone, (2) allowing the 1,3-butadiene monomer to polymerize in said first polymerization zone to a conversion of at least about 90 percent to produce a living polymer solution which is comprised of said organic solvent and living polybutadiene chains having a number average molecular weight which is within the range of about 20,000 to about 60,000, (3) continuously withdrawing said living polymer solution from said first reaction zone, (4) continuously charging styrene monomer, divinyl benzene and the living polymer solution being withdrawn from the first polymerization zone into a second polymerization zone, (5) allowing the styrene monomer and divinyl benzene monomer to polymerize in said second polymerization zone to produce a solution of styrene-butadiene polymer having a number average molecular weight which is within the range of about 30,000 to about 85,000 and (6) continuously withdrawing the solution of said styrene-butadiene polymer from the second polymerization zone.
U.S. Pat. No. 6,136,899 discloses an asphalt concrete which is comprised of (A) from about 90 weight percent to about 99 weight percent of an aggregate and (B) from about 1 weight percent to about 10 weight percent of a modified asphalt cement which is comprised of (1) from about 90 weight percent to about 99 weight percent of asphalt; and (2) from about 1 weight percent to about 10 weight percent of a rubbery polymer which is comprised of repeat units which are derived from styrene and 1,3-butadiene, wherein the styrene-butadiene rubber composition has a number average molecular weight as determined by field flow fractionation which is within the range of about 50,000 to 150,000 and wherein the styrene-butadiene rubber has a light scattering to refractive index ratio which is within the range of 1.8 to 3.9. The rubbery polymer disclosed in U.S. Pat. No. 6,136,899 is comprised of a blend of (i) a high molecular weight styrene-butadiene rubber having a weight average molecular weight of at least about 300,000 and (ii) a low molecular weight styrene-butadiene rubber having a weight average molecular weight of less than about 280,000; wherein the ratio of the high molecular weight styrene-butadiene rubber to the low molecular weight styrene-butadiene rubber is within the range of about 80:20 to about 25:75; and wherein the bound styrene content of the high molecular weight styrene-butadiene rubber differs from the bound styrene content of the low molecular weight styrene-butadiene rubber by at least 5 percentage points.
This invention is based upon the discovery that polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur can be used to improved the force ductility, elastic recovery, toughness and tenacity of asphalt cement. Surprisingly, the polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur exhibits excellent compatibility with asphalt.
The subject invention more specifically relates to a modified asphalt cement which is comprised of (i) from about 90 weight percent to about 99 weight percent asphalt; (ii) from about 1 weight percent to about 10 weight percent of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur.
The present invention also discloses an asphalt concrete which is comprised of (A) from about 90 weight percent to about 99 weight percent of an aggregate and (B) from about 1 weight percent to about 10 weight percent of a modified asphalt cement which is comprised of (i) from about 90 weight percent to about 99 weight percent asphalt; (ii) from about 1 weight percent to about 10 weight percent of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur.
The subject invention further reveals a process for preparing a modified asphalt cement which comprises (1) blending from about 1 to about 10 parts by weight of a polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur into from about 90 to about 99 parts by weight of asphalt at a temperature which is within the range of about 130xc2x0 to about 230xc2x0 C. to produce a polymer-asphalt blend; and (2) mixing from about 0.1 to about 3 parts by weight of sulfur into the polymer-asphalt blend to produce the modified asphalt cement.
The polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur that is used to modify asphalt cement in accordance with this invention can be made by a batch or a continuous emulsion polymerization using a free radical initiator system. This is carried out by adding the conjugated diolefin monomer, sulfur, water, a free radical generator, and a soap system to a polymerization zone to form an aqueous polymerization medium. The polymerization zone will normally be a reactor or series of two or more reactors. Polymerization is initiated with the free radical generator. This polymerization reaction results in the formation of a latex of the polydiene rubber that is comprised of repeat units that are derived from the conjugated diene monomer and sulfur.
The conjugated diolefin monomer will generally contain from 4 to 12 carbon atoms. Those containing from 4 to 8 carbon atoms are generally preferred for commercial purposes. For similar reasons, 1,3-butadiene and isoprene are the most commonly utilized conjugated diolefin monomers. Some additional conjugated diolefin monomers that can be utilized include 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, 2-phenyl-1,3-butadiene, and the like, alone or in admixture.
Other ethylenically unsaturated monomers can also be copolymerized into the polydiene rubber that is comprised of repeat units that are derived from the conjugated diene monomer and sulfur. Some representative examples of additional ethylenically unsaturated monomers that can potentially be synthesized into the polydiene rubber include alkyl acrylates, such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, and the like; vinylidene monomers having one or more terminal CH2xe2x95x90CH-groups; vinyl aromatics, such as styrene, xcex1-methylstyrene, bromostyrene, chlorostyrene, fluorostyrene, and the like; vinyl halides, such as 1,1-dichloroethene (vinylidene chloride), 1,2-dichloroethene, and the like; xcex1,xcex2-olefinically unsaturated nitriles, such as acrylonitrile and methacrylonitrile; xcex1,xcex2-olefinically unsaturated amides, such as acrylamide, N-methyl acrylamide, N,N-dimethylacrylamide, methacrylamide, and the like.
The polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur can be a copolymer of one or more conjugated diene monomers with one or more other ethylenically unsaturated monomers. Such polydiene rubbers will normally contain from about 50 weight percent to about 99 weight percent conjugated diolefin monomers and from about 1 weight percent to about 50 weight percent of the other ethylenically unsaturated monomers in addition to the conjugated diolefin monomers. For example, copolymers of conjugated diolefin monomers with vinylaromatic monomers, such as styrene-butadiene rubbers which contain from 50 to 95 weight percent conjugated diolefin monomers and from 5 to 50 weight percent vinylaromatic monomers, are useful in the asphalt compositions of this invention. In such cases, the polydiene rubber will, of course, also contain repeat units that are derived from sulfur.
Vinyl aromatic monomers are probably the most important group of ethylenically unsaturated monomers that can be incorporated into the polydiene rubbers employed in the asphalt compositions of this invention. Such vinyl aromatic monomers are, of course, selected so as to be copolymerizable with the conjugated diolefin monomers being utilized. Generally, any vinyl aromatic monomer that is known to polymerize with free radical initiators can be used. Such vinyl aromatic monomers typically contain from 8 to 20 carbon atoms. Usually, the vinyl aromatic monomer will contain from 8 to 14 carbon atoms. The most widely used vinyl aromatic monomer is styrene. Some examples of vinyl aromatic monomers that can be utilized include styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, xcex1-methylstyrene, 4-phenylstyrene, 3-methylstyrene, and the like. Terpolymer rubbers of 1,3-butadiene, styrene, and sulfur are particularly preferred.
In synthesizing sulfur containing SBR latex generally from about 10 weight percent to about 40 weight percent styrene and from about 60 weight percent to about 90 weight percent 1,3-butadiene are copolymerized. It is typically preferred for the SBR to contain from about 20 weight percent to about 30 weight percent styrene and from about 70 weight percent to about 80 weight percent 1,3-butadiene. It is normally most preferred for the SBR to contain from about 24 weight percent to about 28 weight percent styrene and from about 72 weight percent to about 76 weight percent 1,3-butadiene. Like ratios of styrene monomer and butadiene monomer will accordingly be charged into the polymerization zone.
U.S. Pat. No. 6,136,899 discloses a styrene-butadiene rubber (SBR) composition that can be used to modify asphalt cement. The styrene-butadiene rubber composition disclosed by U.S. Pat. No. 6,136,899 is a blend of (i) a high molecular weight styrene-butadiene rubber having a weight average molecular weight of at least about 300,000 and (ii) a low molecular weight styrene-butadiene rubber having a weight average molecular weight of less than about 280,000; wherein the ratio of the high molecular weight styrene-butadiene rubber to the low molecular weight styrene-butadiene rubber is within the range of about 80:20 to about 25:75; and wherein the bound styrene content of the high molecular weight styrene-butadiene rubber differs from the bound styrene content of the low molecular weight styrene-butadiene rubber by at least 5 percentage points. These styrene-butadiene rubber compositions are comprised of repeat units which are derived from styrene and 1,3-butadiene, wherein the styrene-butadiene rubber composition has a number average molecular weight as determined by field flow fractionation which is within the range of about 50,000 to 150,000 and wherein the styrene-butadiene rubber has a light scattering to refractive index ratio which is within the range of 1.8 to 3.9. The styrene-butadiene rubber in the compositions disclosed by U.S. Pat. No. 6,136,899 can be modified by conducting the emulsion polymerization in the presence of sulfur in accordance with the technique of this invention. The styrene-butadiene rubber compositions made by such a technique are comprised of repeat units which are derived from styrene, 1,3-butadiene, and sulfur, wherein the styrene-butadiene rubber composition has a number average molecular weight as determined by field flow fractionation which is within the range of about 50,000 to 150,000 and wherein the styrene-butadiene rubber has a light scattering to refractive index ratio which is within the range of 1.8 to 3.9. Such styrene-butadiene rubber compositions can be used advantageously in modifying asphalt compositions. The teachings of U.S. Pat. No. 6,136,899 are accordingly incorporated herein by reference in their entirety.
The amount of sulfur charged into the polymerization zone will typically be within the range of about 0.01 phm (parts per 100 parts by weight of monomer) to about 20 phm and will more typically be within the range of about 0.05 phr to about 5 phm. The amount of sulfur charged into the polymerization zone will preferably be within the range of about 0.1 phm to about 1 phm and will more preferably be within the range of about 0.03 phr to about 0.7 phm. The sulfur charged into the polymerization zone is conventional elemental sulfur. The sulfur will typically be in the form of a powder. It is preferred for the sulfur to be in the form of a powder having a small particle size. For instance, xe2x80x9crubber makers sulfurxe2x80x9d can be used utilized. Optimally, a finely divided dispersion of sulfur in water can be used.
Essentially any type of free radical generator can be used to initiate the free radical emulsion polymerization. For example, free radical generating chemical compounds, ultra-violet light or radiation can be used. In order to ensure a satisfactory polymerization rate, uniformity, and a controllable polymerization, free radical generating chemical agents which are water or oil soluble under the polymerization conditions are typically used.
Some representative examples of free radical initiators which are commonly used include the various peroxygen compounds such as potassium persulfate, ammonium persulfate, benzoyl peroxide, hydrogen peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, decanoyl peroxide, lauryl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, t-butyl hydroperoxide, acetyl acetone peroxide, dicetyl peroxydicarbonate, t-butyl peroxyacetate, t-butyl peroxymaleic acid, t-butyl peroxybenzoate, acetyl cyclohexyl sulfonyl peroxide, and the like; the various azo compounds such as 2-t-butylazo-2-cyanopropane, dimethyl azodiusobutyrate, azodiusobutyronitrile, 2-t-butylazo-1-cyanocyclohexane, 1-t-amylazo-1-cyanocyclohexane, and the like; the various alkyl perketals, such as 2,2-bis-(t-butylperoxy)butane, ethyl 3,3-bis(t-butylperoxy)butyrate, 1,1-di-(t-butylperoxy)cyclohexane, and the like. Persulfate initiators, such as potassium persulfate and ammonium persulfate are especially useful in such aqueous emulsion polymerizations.
The amount of initiator employed will vary with the desired molecular weight of the SBR being synthesized. Higher molecular weights are achieved by utilizing smaller quantities of the initiator and lower molecular weights are attained by employing larger quantities of the initiator. However, as a general rule from 0.005 to 1 phm (parts by weight per 100 parts by weight of monomer) of the initiator will be included in the reaction mixture. In the case of metal persulfate initiators most commonly from 0.1 to 0.5 phm will be employed in the polymerization medium.
A wide variety of soap systems can be used to emulsify the polymerization medium. For instance, an anionic, cationic or non-ionic emulsifier can be employed. A combination of rosin acid and fatty acid emulsifiers can be employed with excellent results. In such systems, the weight ratio of fatty acid soaps to rosin acid soaps will be within the range of about 50:50 to 90:10. It is normally preferred for the weight ratio of fatty acid soaps to rosin acid soaps to be within the range of 60:40 to 85:15. It is normally more preferred for the weight ratio of fatty acid soaps to rosin acid soaps to be within the range of 75:25 to 82:18. All of the soap is charged into the first polymerization zone in practicing this invention. The total amount of soap employed will normally be within the range of about 1 phm to 5 phm. It is typically preferred to utilize a level of soap that is within the range of about 2 phm to about 3.5 phm. In most cases it will be most preferred to use an amount of the soap system which is within the range of about 2.5 phm to 3 phm. The precise amount of the soap system required in order to attain optimal results will, of course, vary with the specific soap system being used. However, persons skilled in the art will be able to easily ascertain the specific amount of soap system required in order to attain optimal results.
The free radical emulsion polymerization will typically be conducted at a temperature which is within the range of about 20xc2x0 F. to about 80xc2x0 F. It is generally preferred for the polymerization to be carried out at a temperature that is within the range of 30xc2x0 F. to about 65xc2x0 F. It is typically more preferred to utilize a polymerization temperature which is within the range of about 45xc2x0 F. to about 55xc2x0 F. To increase conversion levels, it can be advantageous to increase the temperature as the polymerization proceeds.
The polymerizations employed in making the polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur are typically initiated by adding the initiator to the aqueous polymerization medium that contains the conjugated diene monomer, sulfur, water and emulsifier. Such polymerizations are typically carried out utilizing continuous polymerization techniques. In such continuous polymerizations, monomer and initiator are continuously added to the organic polymerization medium with a latex of the polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur being continuously withdrawn. Such continuous polymerizations are typically conducted in a multiple reactor system.
The polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur. The polydiene rubber can, of course, be derived from more than one conjugated diolefin monomers and one or more additional monomers, such as vinyl aromatic monomers. The repeat units in the polydiene rubber that are derived from sulfur are in the backbone of the polymer. These repeat units that are derived from sulfur typically contain from 2 to 8 sulfur atoms (xe2x80x94Snxe2x80x94). It is believed that S8 molecules are incorporated into the backbone of the polymer by a ring opening reaction. In any case, the latex of the polydiene rubber is comprised of water, an emulsifier, and the polydiene rubber.
Asphalt cement can be modified with the polydiene rubber that is comprised of repeat units that are derived from a conjugated diene monomer and sulfur by simply mixing a latex of the polydiene rubber into hot asphalt. The latex of the polydiene rubber will typically be mixed into the asphalt at a temperature which is within the range of about 130xc2x0 C. to about 230xc2x0 C. The latex of the polydiene rubber may be added to the asphalt in an amount which is within the range of from about 1 part by weight to about 10 parts by weight (based upon the dry weight of the rubber). Preferably, from about 1 part by weight to about 6 parts by weight of the polydiene rubber is added with amounts within the range of from about 2 parts by weight to about 4 parts by weight being particularly preferred. After the latex of the polydiene rubber has been well dispersed throughout the asphalt, elemental sulfur can optionally be added to the polymer/asphalt blend. Normally from about 0.1 to about 5 parts by weight of sulfur is added per 100 parts by weight of the polydiene rubber. In most cases, it is preferred to utilize from about 1 to about 4 parts by weight of sulfur per 100 parts by weight of the polydiene rubber. It is typically more preferred to utilize from about 2 to about 3 parts by weight of sulfur per 100 parts by weight of the polydiene rubber. After the polydiene rubber and the sulfur has been thoroughly mixed with the asphalt cement, one should store the modified asphalt cement at elevated temperatures to avoid solidification prior to use.
Virtually any type of asphalt can be employed in making the asphalt cement compositions of this invention. Asphalt is defined by ASTM as a dark brown to black cementitious material in which the predominant constituents are bitumens that occur in nature or are obtained in petroleum processing. Asphalts characteristically contain very high molecular weight hydrocarbons called asphaltenes. These are essentially soluble in carbon disulfide and aromatic and chlorinated hydrocarbons. Bitumen is a generic term defined by ASTM as a class of black or dark-colored (solid, semi-solid or viscous) cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons, of which asphalts, tars, pitches, asphaltites are typical. ASTM further classifies asphalts or bituminous materials as solids, semi-solids or liquids using a penetration test for consistency or viscosity. In this classification, solid materials are those having a penetration at 25xc2x0 C. under a load of 100 grams applied for 5 seconds, of not more than 10 decimillimeters (1 millimeter). Semi-solids are those having a penetration at 25xc2x0 C. under a load of 100 grams applied for 5 seconds of more than 10 decimillimeters (1 millimeter) and a penetration at 25xc2x0 C. under a load of 50 grams applied for 1 second of not more than 35 millimeters. Semi-solid and liquid asphalts predominate in commercial practice today.
Asphalts are usually specified in several grades for the same industry, differing in hardness and viscosity. Specifications of paving asphalt cements generally include five grades differing in either viscosity level at 60xc2x0 C. or penetration level. Susceptibility of viscosity to temperatures is usually controlled in asphalt cement by its viscosity limits at a higher temperature such as 135xc2x0 C. and a penetration or viscosity limit at a lower temperature such as 25xc2x0 C. For asphalt cements, the newer viscosity grade designation is the mid-point of the viscosity range.
The asphalt materials that may be used in the present invention are those typically used for road paving, repair and maintenance purposes. Petroleum asphalts are the most common source of asphalt cements. Petroleum asphalts are produced from the refining of petroleum and used predominantly in paving and roofing applications. Petroleum asphalts, compared to native asphalts, are organic with only trace amounts of inorganic materials. Some representative examples of asphalt cements that may be used in the present invention have an ASTM grade of AC-2.5, AC-5, AC-10, AC-20 and AC-40. The preferred asphalt cements include AC-5, AC-10 and AC-20.
The present invention may contain other conventional additives in addition to the polydiene rubber, the asphalt cement, and optionally, the sulfur. Examples of conventional additives include antistripping compounds, fibers, release agents and fillers. Some specific examples of additives that can be employed include kaolin clay, calcium carbonate, bentonite clay, and cellulose fibers.
After the asphalt cement has been modified, it can be mixed with aggregate to make asphalt concrete using standard equipment and procedures utilized in making asphalt concrete. As a general rule, from about 1 weight percent to about 10 weight percent of the modified asphalt cement and from about 90 weight percent to about 99 weight percent aggregate will be included in the asphalt concrete. It is more typical for the asphalt concrete to contain from about 3 weight percent to about 8 weight percent of the modified asphalt cement and from about 92 weight percent to about 97 weight percent of the aggregate. It is normally preferred for the asphalt concrete to contain from about 4 weight percent to about 7 weight percent of the modified asphalt cement and from about 93 weight percent to about 96 weight percent of the aggregate.
The aggregate is mixed with the asphalt to attain an essentially homogeneous asphalt concrete. The aggregate is mixed with the asphalt cement utilizing conventional techniques and standard equipment. For instance, the aggregate can be mixed with asphalt to produce asphalt concrete on a continuous basis in a standard mixer.
Standard aggregate can be utilized in the practice of this invention. The aggregate is essentially a mixture containing rocks, stones, crushed stone, gravel and/or sand. The aggregate will typically have a wide distribution of particle sizes ranging from dust to golf ball size. The best particle size distribution varies from application to application. In many cases, it will be advantageous to coat the aggregate with latex in accordance with the teachings of U.S. Pat. No. 5,262,240 to improve resistance to stripping by water.
The asphalt concrete made using the modified asphalt cement of this invention can then be used to pave roads, highways, exit ramps, streets, driveways, parking lots, airport runways or airport taxiways utilizing conventional procedures. However, pavements made utilizing the asphalt concretes of this invention offer resistance to rutting, shoving and low temperature cracking. Additionally, they can be applied without encountering processing difficulties due to the latex used for the modification being incompatible with the asphalt.
This invention is illustrated by the following examples that are merely for the purpose of illustration and are not to be regarded as limiting the scope of the invention or the manner in which it can be practiced. Unless specifically indicated otherwise, all parts and percentages are given by weight.


An object of the present invention is to provide a pedal device in which the pad member can be fixed to the stopper member easily at the time of mounting, and which does not tend to be degraded over the years. In order to achieve the above object, the present invention provides a pedal device including: a stopper member attached to a floor of a driver's seat of a vehicle; and a pad member which has a pad fitted into the stopper member and receives a depression force exerted by a driver.

1. Field of the Invention
The present invention relates to a pedal device which is provided in a vehicle.
2. Description of Related Art
For example, a pedal (an organ pedal) whose fulcrum is on a floor side of a vehicle body may be used as an accelerator pedal of a vehicle. JP 2004-106776 A discloses an accelerator pedal in which a pad member is fixed to a stopper member by a snap-fit mechanism by which a nail member including a nail provided on a resinous pad member is engaged with the stopper member on a vehicle body side at the time of mounting.
According to the technique disclosed in JP 2004-106776 A, the nail is engaged with the stopper member by the snap-fit mechanism which elastically deforms a supporting plate which connects the nail to the resinous pad member. Therefore, the supporting plate should be formed to be thin so that it can be elastically deformed enough.
Also, because the nail is engaged with the stopper member by elastically deformed supporting plate, an amount of deformation of the supporting plate increases when the nail is large. Therefore, the nail should be made to be small so as to suppress the amount of deformation of the supporting plate.
Therefore, there arises a problem that the accelerator pedal tends to be degraded over the years because the strength of the nail member including the supporting plate and the nail decreases.
Therefore, an object of the present invention is to provide a pedal device in which the pad member can be fixed to the stopper member easily at the time of mounting, and which does not tend to be degraded over the years.


A developing device usable with an image forming apparatus having a developer delivery device of an improved drive configuration. The developing device includes a developer storage unit, a rotating member arranged in the developer storage unit, and a plurality of developer delivery members arranged in an axial direction of the rotating member to be rotated around the rotating member upon receiving rotation power from the rotating member. A first power-transmission structure may be provided between at least one of the plurality of developer delivery members and the rotating member to allow slip therebetween.

1. Field of the Invention
Embodiments of the present general inventive concept relate to a developing device usable with an image forming apparatus having a developer delivery device to deliver developer stored in a developer storage unit.
2. Description of the Related Art
Generally, image forming apparatuses are devised to form an image on a printing medium according to inputted image signals. Examples of image forming apparatuses include printers, copiers, facsimiles, and so-called multi-functional devices that combine some of the functionalities of the aforementioned devices.
An electro-photographic image forming apparatus as a kind of the aforementioned image forming apparatuses includes a photosensitive body, a light scanning device, and a developing device. The light scanning device irradiates light to a surface of a photosensitive body that has been charged by a predetermined electric potential, thereby forming an electrostatic latent image on the surface of the photosensitive body. The developing device supplies developer to the electrostatic latent image, thereby forming a visible image.
The visible image formed on the photosensitive body is directly transferred to the printing medium or is indirectly transferred to the printing medium by way of an intermediate transfer device. The transferred image is fused to the printing medium via a fusing process.
Generally, the developing device includes a developer receiving chamber, a developer delivery device, and a developing member. The developer receiving chamber stores developer therein, and the developer delivery device delivers the developer from the developer receiving chamber to the developing member. The developing member supplies the developer to the photosensitive body, enabling formation of a visible image.

Developing device usable with image forming apparatus and developer delivery device thereof including a plurality of rotatable delivery members


A drawing device includes: a display unit that displays an editing screen for creating a plurality of screens to be displayed on a programmable display device; a screen data generation unit that generates screen data configured by the plurality of screens and including an object that is a display element arranged on the editing screen; a screen script generation unit that generates a screen script that is a processing program to be executed only when a specific screen out of the plurality of screens to be displayed on the programmable display device is displayed; and an association management unit that manages an association between the object and the screen script. When the object is copied from a source editing screen to a destination editing screen, the screen script generation unit registers, with the destination editing screen, the screen script associated with the object to be copied.

A programmable display device displays, on a monitor screen, the state of an external instrument connected to the programmable display device, and operates the external instrument according to an input operation. A drawing device generates screen data indicating the contents of a screen that is displayed on the monitor screen based on the arrangement of objects on an editing screen displayed on the drawing device. An object is a display element arranged on an editing screen. The drawing device also generates object scripts and screen scripts. An object script is attribute information of an object and is also a processing program for executing a function set for the object. A screen script describes processing for a unit of a single screen that is displayed on the monitor screen.
Patent Literature 1 relates to a graphic operation panel capable of creating an operation panel for any display screen using drawing software, and discloses that a screen script which is an operation program accompanying a screen can be registered with display screen data for displaying a display screen.

Drawing device, drawing program, and non-transitory computer-readable storage medium for editing and managing associations between object, screen, and project scripts


The present inventors succeeded in developing a vector that expresses high levels of a foreign gene in plant seeds by utilizing a 5′-untranslated region of a gene encoding a seed storage protein. The inventors also succeeded in accumulating high levels of a foreign gene product in plant seeds by utilizing a seed storage protein defective mutant as a target for foreign gene transfer.

Seed storage proteins are conventionally classified into four groups of proteins, according to their solubility, i.e., glutelin, globulin, prolamin, and albumin. Rice is different from other grains, such as wheat and maize, in that glutelin is the major seed storage protein, accounting for about 70 to 80% of the seed storage proteins. The glutelin gene group comprises about 10 genes per one haploid genome, and the genes are divided into two subfamilies, GluA and GluB, which show a homology of 60 to 65% at the amino acid sequence level within the coding region. Each subfamily comprises about 5 genes that have a homology of 80% or higher at the amino acid sequence level. A glutelin gene is specifically expressed and accumulated in the endosperm. The tissue specificity of glutelin expression is considerably strictly regulated, and glutelins are not expressed in other tissues, such as leaf and root. The expression of the glutelin gene group, with the exception of GluA-3, is generally coordinated; their mRNA levels show the following pattern: emerging 5 days after flowering (day 5), reaching maximum at around day 15, and decreasing thereafter. The GluB-1 gene has the strongest promoter activity in the glutelin gene group.
Rice mutants with decreased amount of accumulated glutelin, i.e., the major seed storage protein, have been isolated. For example, Iida et al. isolated recessive mutants that lack either one of the acidic subunits of glutelin, α1, α2, or α3, from a rice breed Koshihikari that was irradiated with γ-ray. The phenotypes are respectively regulated by a single recessive gene (i.e., glu1, glu2, or glu3). A mutant strain (α123) that lacks all of α1, α2, and α3 has been also obtained by crossing the above three mutants (Iida, S. et al., Theor. Appl. Genet. 94: 177-183 (1997)).
LGC-1 (low glutelin content-1) is a mutant selected from Nihonmasari treated with EMS, and has a phenotype with a significantly reduced level of glutelin (Iida, S. et al., Theor. Appl. Genet. 87: 374-378 (1993) ). LGC-1 is further characterized by increased levels of prolamin and globulin. LGC-1 is dominated by a single dominant gene. By mapping the defective genes in LGC-1 and the mutants defective of α1, α2, and α3, it was revealed that the mutated protein gene (lgc-1) in LGC-1 and the mutated glutelin gene (glu1) in the mutant lacking α1 are localized on the same locus. The results of Southern hybridization using the glutelin (GluB) gene as a probe suggested that LGC-1 contained a mutation in the GluB gene or in the proximity thereof. According to the results of Northern blot analysis, comparing the expression level of the GluB gene in the endosperm after about 16 days from head spout in LGC-1 and its original breed, Nihonmasari, it was revealed that GluB expression is markedly decreased in LGC-1.
In soybean, glycinin is known as a seed storage protein. Glycinin is produced as a precursor polypeptide of a size of about 60 kDa wherein a signal peptide, an acidic polypeptide, and a basic polypeptide are bound together; the signal peptide is cleaved afterwards. Thereafter, a subunit is formed wherein two kinds of polypeptides that result from a cleavage at the Asn-Gly site—i.e., the specific acidic polypeptide (A) and basic polypeptide (B)—are polymerized through disulfide bonds. Six of these subunits are assembled to form a hexamer, and are stored in the protein body (PB) The hexamer is also called "11S seed storage protein", due to its sedimentation coefficient (11S). Glycinin subunits are classified into group I and group II based on the primary structure of their cDNAs and their amino acid sequence homology. To date, subunits A1aB1b, A1bB2, and A2B1a of group I, and subunits A3B4, and A5A4B3 of group II are known. Six of these subunits are known to be almost randomly combined in soybean glycinin. Furthermore, a peptide derived from the A1aB1b subunit of soybean glycinin has been reported to have the ability to bind to bile acid (Shio Makino, The Food Industry 39(24): 77-87 (1996)), which suggests that the ability of soybean proteins to decrease the cholesterol level in blood is dependent on the A1aB1b subunit.

Method of accumulating foreign gene product in plant seed at high level

National Institute of Agrobiological Sciences

National Agriculture and Bio-Oriented Research Organization


Disclosed herein is an electroluminescence display panel including a pixel circuit, a signal line, a scan line, a drive power supply line, a common power supply line, a power supply line drive circuit, a high-potential power supply line, and a low-potential power supply line.

1. Field of the Invention
The present invention relates to a technology for enhancing the yield of EL (Electro Luminescence) display panels and has modes of as an EL display panel, a power supply line drive apparatus, and an electronic device. It should be noted that the EL display panel denotes a self-illuminant display apparatus with EL devices arranged in matrix on a substrate made of glass or other materials.
2. Description of the Related Art
Recently, organic EL panels on which organic EL devices are arranged in matrix have been drawing attention. This is because organic EL panels are excellent in moving picture display characteristics as well as easy in reducing apparatus weight and film thickness.
Currently, two organic EL panel driving schemes are available; passive matrix driving and active matrix driving. Especially, organic EL panels based on the active matrix driving in which an active element (a thin-film transistor) and a hold capacity are arranged for every pixel circuit are under brisk development.
The following shows documents associated with the active matrix driving, for example.    Patent Document 1: Japanese Patent Laid-Open No. 2003-255856    Patent Document 2: Japanese Patent Laid-Open No. 2003-271095    Patent Document 3: Japanese Patent Laid-Open No. 2004-029791    Patent Document 4: Japanese Patent Laid-Open No. 2004-093682
As shown in the above-mentioned Patent Documents, the active matrix driving is of various types. Described in what follows is one of these driving schemes that controls the on state and the off state of each organic EL device by digitally driving one of two power supply lines for supplying a power supply potential to each pixel circuit.
Now, referring to FIG. 1, there is shown an exemplary pixel circuit of the above-mentioned type. A pixel circuit 1 is made up of two N-type thin-film transistors T1 and T2. Of these two transistors, the thin-film transistor T1 is a switching transistor that controls writing of a signal line voltage Vsig to a storage capacity Cs.
On the other hand, the thin-film transistor T2 is a driving transistor that supplies drive current Ids of a magnitude corresponding to a hold voltage Vgs of a storage capacity Cs to an organic EL device D1. The thin-film transistors T1 and T2 are connected to a signal line as follows.
A gate electrode of the thin-film transistor T1 is connected to a scan line SCNL(i) (i being a serial number indicative of row position) that gives a signal line potential write timing. In FIG. 1, a write timing signal is indicated by SCNL(i).
One main electrode of the thin-film transistor T1 is connected to a signal line DL(j) (j being a serial number indicative of a column position) and the other main electrode is connected to a gate electrode of the thin-film transistor T2 and an electrode of the storage capacity Cs.
One main electrode of the thin-film transistor T2 is connected to a drive power supply line DSL(i) (i being a serial number indicative of row position) and the other main electrode is connected to a positive electrode (or an anode electrode) of an organic EL device OLED. In FIG. 1, power supply potential of a high potential (also referred to as a high power supply potential) to be applied to a drive power supply line DSL(i) is indicated by Vcc_H and a power supply potential of low potential (also referred to as a low power supply potential) is indicated by Vcc_L1.
It should be noted that a negative electrode (or a cathode electrode) of the organic EL device OLED is connected to a common power supply line (or a ground line). In FIG. 1, a power supply potential of low potential to be applied to the common power supply line is indicated by Vcc_L2. Meanwhile, the organic EL device OLED is a current-driven element. Therefore, it is desired to flow a current (rn) obtained by multiplying current I flowing through one pixel circuit by the number of pixels (or n times) to the drive power supply line DSL(i) that is emitting light.
Hence, a wiring resistance of the drive power supply line DSL(i) located on a route along which the power supply potential of high potential is supplied has to be relatively small. If the wiring resistance is large, a voltage drop difference occurs across the drive power supply line DSL(i) to cause problems of a luminance difference depending on the location of scan line and generating heat in the power supply line, for example.
If the number of stages of scan lines making up a valid display area is V, then it is desired to flow current (I*n*V) obtained by multiplying the number of pixels (n times) of current I flowing to one pixel circuit by the number of stages (V times) to a high-potential power supply line that supplies high-potential power supply potential Vcc_H to each drive power supply line DSL(i).
Consequently, it is technically necessary for both the drive power supply line DSL(i) and the high-potential power supply line to be relatively large in wiring width so as to lower the wiring resistance. The following describes these technological requirements with reference to FIGS. 2 and 3. FIG. 2 shows a connection relationship between the pixel circuit 1 and a power supply line drive circuit 3. FIG. 3 shows a wiring pattern of a connected portion between the drive power supply lines DSL and a power supply line drive circuit 7 (or an output stage buffer circuit).
The power supply line drive circuit 3 is made up of a shift register 5 that transfers a power supply line drive pulse to a next scan line for each horizontal scan interval and a buffer circuit 7 (2-stage configuration of input-stage buffer circuit and output-stage buffer circuit).
The two stages of buffer circuits making up the buffer circuit 7 are each configured by a CMOS inverter circuit. In the case of FIG. 2, each p-channel MOS transistor is connected to a high-potential power supply line 11 and each n-channel MOS transistor is connected to a low-potential power supply line 13.
Consequently, if the power supply drive pulse is at H level, high-potential power supply potential Vcc_H is supplied to the drive power supply line DSL(i); if the power supply line drive pulse is at L level, low-potential power supply potential Vcc_L is supplied to the drive power supply line DSL(i).
Meanwhile, if the drive power supply line DSL(i) wide in wiring and the high-potential power supply line 11 are arranged in a crossed manner, a resultant cross area becomes wide. And, this cross appears for every drive power supply line DSL(i). Therefore, let one cross area be S, then a cross area of the entire organic EL panel becomes as large as S*V (V being the number of scan lines or the number of vertical resolutions).
Thus, the wiring pattern shown in FIG. 3 that may not avoid the increase in cross area involves a problem of causing an inter-layer short circuit due to dust or the like. This, in turn, may raise the detect rate of organic EL panels. In addition, the above-mentioned wiring pattern causes an increased capacity that is parasitic to the cross portion, thereby increasing the distortion of a potential waveform of the drive power supply line DSL(i).

This patent is subject to a terminal disclaimer.

EL display panel, power supply line drive apparatus, and electronic device


An abrasive article backup plate assembly and grinder system having an abrasive article backup plate assembly is disclosed. The abrasive article backup plate assembly includes an abrasive article having an abrasive surface that includes a viewing window within the abrasive surface. A support member is provided including a first major surface which supports the abrasive article. At least a portion of the support member is made of materials sufficiently clear to collectively see through the support member and the viewing window. A method of abrading a surface using a grinder system including the abrasive article backup plate assembly is also disclosed.

The present invention relates generally to a backup plate assembly for grinding systems, preferably a backup plate assembly for use in a grinding system which allows observation of a work surface during operation of the grinding system.
High-speed grinders are used for many different applications for abrading a work surface. Typical rotary grinders include a rotatable shaft extending from the grinder. An abrasive disc attached to a backup plate is mounted on an end of the rotatable shaft. Typical grinding operations include positioning the grinding system at an angle relative to the work surface during operation of the grinding system. The grinder is held at an angle, such that the rotatable shaft is angled relative to a plane of the work surface. Typical grinding angles range from about 5xc2x0 to 45xc2x0. An outer edge of the abrasive disc and backup plate assembly is pressed against the work surface while the grinder is operated. The result is an abrading of the work surface by the abrasive article.
During operation of the grinder system on a work surface it is desirable to view the abraded portion of the work surface. Typically, this is accomplished by abrading the work surface, moving the grinder system to view the abraded portion of the work surface, and repositioning the grinder system at the abraded portion of the work surface. This routine is repeated until grinding is complete.
Modifications have been made to the abrasive disc and backup plate assembly in order to view the abraded work surface during operation of the grinder system (see, for example, U.S. Pat. No. 6,007,415 (Van Osenbruggen)). Known abrasive disc and backup plate assembly designs include circular openings or apertures in a sanding disc and corresponding circular openings or apertures in the backup plate. When rotated at a high speed during operation of the grinder system, the abraded work surface is viewable through the apertures in the sanding disc and apertures in the backup plate. This type of sanding disc and backup plate assembly requires that the openings in the sanding disc be designed to match with the openings in the backup plate. The openings in the sanding disc must be registered and aligned with the openings in the backup plate, and such registration must be maintained while mounting the sanding disc and backup plate assembly on the grinder system rotatable shaft.
Other abrasive disc and backup pad assemblies include portions or regions removed from the outside perimeters of the abrasive disc and backup plate to enable viewing of an abraded work surface during operation of a grinder system (see, for example, U.S. Pat. No. 6,062,965 (Knowlton)). Again, the removed regions about the outer perimeters of the sanding disc must correspond to the removed regions about the outer perimeter of the backup plate. The sanding disc removed regions must be registered and aligned to the removed regions of the backup plate and secured to the rotatable shaft of the grinder system. Another known grinding disc is disclosed having both apertures extending through the disc surface and removed regions spaced about the outer circumference of the grinding disc (see, for example, U.S. Pat. No. 6,077,156 (Amin et al.)).
It is also known to provide openings or apertures in a grinder backup plate as part of a dust control system. The dust control system includes a shroud placed over the openings in the backup plate and is connected to a vacuum source. During operation of the grinder, dust, dirt, and abraded material (termed xe2x80x9cswarfxe2x80x9d) is removed through the apertures and shroud via the vacuum system (see, for example, U.S. Pat. No. 4,932,163 (Chilton et al.)).
Other known systems have been designed to aid in cooling of the abrasive disc during grinder operation, thereby extending the useful life of the abrasive disc. For example, one known design includes, a plurality of ribs extending from a surface of the backup plate. The ribs extending from a surface of the backup plate provide both channels for removal of xe2x80x9cswarfxe2x80x9d or other undesirable materials during operation of the grinder system while providing a cooling effect to the grinding disc.
The present invention relates generally to an abrasive article backup plate assembly for grinding systems, preferably an abrasive article backup plate assembly for use in a grinding system which allows observation of an abraded surface during operation of the grinding system and grinding systems employing such assemblies.
In one embodiment, the present invention provides an abrasive article backup plate assembly. The abrasive article backup plate assembly includes an abrasive article having an abrasive surface that includes a viewing window (preferably, two or more viewing windows) within the abrasive surface. A support member is provided which includes a first major surface which supports the abrasive article. At least a portion of the support member is made of material sufficiently clear to collectively see through the support member and the viewing window. For embodiments in which the assembly rotates during use, preferably at least a portion of the support member is made of material sufficiently clear to allow observation of a work surface collectively through the support member and the viewing window during rotation of the assembly about an axis substantially perpendicular to the first major surface.
In another embodiment, the present invention provides an abrasive article backup plate assembly. The abrasive article backup plate assembly includes an abrasive article having an abrasive surface having an average diameter. A portion of the abrasive surface projects beyond the average diameter such that there is a first viewing area between a first two adjacent portions of the abrasive surface that project beyond the average diameter of the abrasive surface. A support member is provided including a first major surface which supports the abrasive article. A portion of the support member is made of material sufficiently clear to collectively see through the support member and the abrasive article viewing area. For embodiments in which the assembly rotates during use, preferably at least a portion of the support member is made of material sufficiently clear to allow observation of a work surface collectively through the support member and the viewing window during rotation of the assembly about an axis substantially perpendicular to the first major surface. Optionally, the abrasive article includes two or more viewing areas. Optionally, the viewing area(s) is a viewing window(s). In another aspect, the abrasive article includes a viewing window(s) in addition to the viewing area(s).
In another embodiment, the present invention provides a grinder system. The grinder system includes a grinder having a shaft (typically, longitudinally extending shaft) and an abrasive article backup plate assembly according to the present invention attached thereto. Typically, a hub system is attached to the support member, wherein the hub system is connectable to the longitudinally extending shaft.
The present invention also provides a method of abrading a surface utilizing an abrasive article backup plate assembly according to the present invention. At least a portion of the abrasive of the abrasive article backup plate assembly may be contacted with a substrate surface to be abraded, and at least one of the abrasive article backup plate assembly or substrate surface may be moved relative to the other. For example, the abrasive article backup plate assembly may be rotated about an axis.
The abrasive article backup plate assembly according to the present invention includes a support member made of materials sufficiently clear to allow observation through the support member, and as such does not require registration or alignment with viewing windows or viewing areas of an abrasive article prior to mounting the abrasive article backup plate assembly onto a grinder system. The clear backup plate can be universally used with many different shapes and configurations of abrasive articles.

Buckup plate assembly for grinding system


The present invention relates to an apparatus packaging components of an optical reading device which may include illumination optical elements, receive optical elements, and signal processing elements. In one embodiment a single circuit board can carry multiple elements such as an image sensor together with illumination elements. In one embodiment, a control circuit can be provided that is coupled to a light source and an image sensor.

Currently available optical readers include illumination elements, electronic signal processing, image capture and decoding circuitry that are carried by more than one circuit board. For example, shown in U.S. Pat. No. 5,780,834 is an optical reader having numerous circuit boards, including an LED board for carrying illumination LEDs, an "imaging board" carrying an image sensor and circuitry for processing signals generated from the image sensor, and a "mother board" carrying image capture and decoding circuitry.
Assembly of the multiple circuit board arrangement of the prior art is time consuming and expensive. Assembly of a prior art reader requires mounting of separate circuit boards to separate internal structures of a reader, and providing electrical connection between the multiple circuit boards. In addition adding to being difficult to assemble, the multiple circuit board design imposes size requirements on the optical reader housing in which the electrical components are to be integrated.
There is a need for an improved packaging method and apparatus for packaging optical and electrical components of an optical reader.


A method for designing a system on a field programmable gate array (FPGA) includes performing mapping with a plurality of passes where a different assumption is made with respect to a property of the FPGA during each pass.

FPGAs may be used to implement large systems that include millions of gates and megabits of embedded memory. Today, FPGAs may utilize fracturable logic cells. Fracturable logic cells include a variety of look-up table (LUT)-based resources that can be used to implement a single adaptive LUT having a first number of inputs or be divided between a plurality of adaptive LUTs having the same or a different number of inputs. Each fracturable logic cell may be used to implement more than one function. Compared to traditional logic cells that may only implement a single function, fracturable logic cells provide designers with more flexibility and more opportunities to maximize the utilization of resources on FPGAs.
The process flow for implementing a system onto a target FPGA device includes performing synthesis, mapping, placement, and routing. Synthesis involves generating a logic design of the system to be implemented by a target device and mapping the logic design onto resources on the FPGA that will implement the logic design. Traditional mapping techniques map components in the logic design onto LUTs assuming that each LUT supports a fixed number of inputs. Although sufficient for traditional FPGA devices, these mapping techniques are not well suited for FPGAs implementing fracturable logic cells having adaptive LUTs that support more than a single number of inputs. By assuming that the adaptive LUTs support only a single number of inputs, these mapping techniques may create inefficient solutions by either generating too many unpackable adaptive LUTs that would waste resources or fail to fully take advantage of the functionality of the adaptive LUTs to implement functions with a higher number of inputs.
Thus what is needed is an effective method and apparatus for performing mapping onto FPGAs utilizing fracturable logic cells.

Method and apparatus for performing mapping onto field programmable gate arrays utilizing fracturable logic cells


A light deflecting apparatus includes first and second light deflecting liquid crystal cells, each corresponding to each eye of a user and each comprising a liquid crystal layer including liquid crystal molecules with positive dielectric anisotropy and exhibiting a cholesteric blue phase when no voltage is applied, a pair of transparent substrates sandwiching the liquid crystal layer, a pair of transparent electrodes each being formed above each transparent substrate, a prism layer formed above one of the transparent substrates, and a driving device switching between a first state wherein the first and the second light deflecting liquid crystal cells are respectively in a homeotropic phase and a cholesteric blue phase, and a second state wherein the first and the second light deflecting liquid crystal cells are respectively in a cholesteric blue phase and a homeotropic phase.

A) Field of the Invention
This invention relates to a light deflecting apparatus which deflects a direction of light by using a liquid crystal device.
B) Description of the Related Art
Glasses using liquid crystal shutters for watching three-dimensional images have been suggested (for example, refer to JPA H6-178325). This kind of glasses for three-dimensional imaging (hereinafter the 3D glasses) makes light on a left eye side pass through it but shades light on a right eye side when displaying images for a left eye for three-dimensional images, whereas it makes light on a right eye side pass through it but shades light on a left eye side when displaying images for a right eye for three-dimensional images. The crystal liquid shutter used in that kind of 3D glasses uses a polarizer so that optical transmittance is hardly improved. A novel technique for optical devices which can be applied to 3D glasses is desired.
Recently researches on a cholesteric blue phase for liquid crystal material have been carried out, and a technique for enlarging an appearance temperature range of a cholesteric blue phase by a polymer stabilization process has been suggested (for example, refer to JPA 2003-327966).


An image-forming apparatus for developing an electrostatic latent image using a two-component developer. Toner replenishment is effected in different modes when the toner concentration is in a lower toner concentration range than a desired toner concentration and when it is lower than that toner concentration range.

1. Field of the Invention
This invention relates to an image-forming apparatus, in which an electrostatic latent image is formed by such means as an electro-photographic system or electrostatic recording system and developed with a developer including a toner and a carrier.
2. Related Background Art
In a well-known extensively used image-forming apparatus including a step of visualizing a latent image formed on an image carrier surface with a toner attached to the image, a two-component developer is used, which includes toner particles and carrier particles.
In the image-forming apparatus used with such a two-component developer, it is the toner that is actually consumed to form a developed image, and the carrier is hardly consumed. Therefore, when the developing operation is continued in this apparatus, the amount of toner contained in the developer is inevitably reduced to reduce image concentration. Therefore, it is necessary to detect the proportion of toner in the developer, i.e., toner concentration, and replenish with toner when the toner concentration is reduced.
Various toner concentration sensors have been proposed and used in practice. Among these means are optical means, which detects a change in the light reflectivity of the developer caused by a change in the toner concentration, and magnetic means, which detects a change in magnetic permeability of the developer.
However, the amount of toner that is consumed varies depending on the image ratio of an original that is copied; for instance, a difference in the toner consumption by ten or more times is produced between an original with an image ratio of 6% and an original with an image ratio of 100%. Therefore, if the amount of toner supplied from a toner replenishment port to a toner vessel or container in one cycle of replenishment is reduced, the toner concentration becomes insufficient eventually by continuing the copying of an original having a high image ratio.
On the other hand, when the amount of replenishment toner supplied per cycle is increased, a temporary excessive toner concentration condition is produced when replenishment toner is supplied while copying an original having a low image ratio, and this leads to deterioration of the image quality.
To solve the above problems, a small quantity of replenishment toner is supplied per cycle to reduce the change in the toner concentration at the time of supply of replenishment toner. When the copying of a high image ratio original is continued, the number of toner replenishment cycles is temporarily increased, or the copying operation is temporarily suspended and resumed after restoration of the toner concentration to a predetermined value.
The graphs of FIGS. 1 and 2 show the toner concentration controlled in the above way in the case when a toner concentration sensor provides a potential signal as a detected toner concentration signal. FIG. 1 shows the toner concentration when low image ratio original is copied, and FIG. 2 shows when a high image ratio original is copied. In the graphs, the ordinate is the sensor output voltage (representing toner concentration), and the ordinate is the number of copy sheets or time. In these Figures, designated at Vb is the voltage corresponding to the detected toner concentration, and Vc a voltage corresponding to a desired toner concentration To, i.e., reference value. The toner concentration of the developer can be controlled in the neighborhood of the reference value Vc by repeatedly causing operations of discontinuing replenishment toner supply when copying low image ratio original, i.e., when Vb.gtoreq.Vc, and resuming toner supply when Vb<Vc. In other words, while replenishment with toner is being made according to toner consumption, the sensor output voltage Vb is varied, i.e., increased and reduced with respect to the reference value Vc, between values Vmax and Vmin corresponding to respective limit toner concentrations, i.e., limits of a permissible image density range.
However, when the image ratio is increased or when toner consumption exceeds toner replenishment so that a condition Vb>Vc is continued for more than t seconds, for instance, a predetermined toner concentration can not be maintained unless the copying operation is temporarily suspended or the cycles of toner replenishment are increased. Where such toner concentration control is made, however, if the preset time t is too short, the operation noted above is caused even when the toner consumption does not exceed the toner replenishment. For this reason, a considerably long time has to be set as time t. Therefore, an insufficient toner concentration condition as shown at a in FIG. 2 or excessive toner concentration condition as shown at b due to temporary excessive toner replenishment are produced, leading to image quality deterioration.


The present subject matter describes a balloon catheter and methods of using the balloon catheter. The balloon catheter is particularly useful for pericardiocentesis and percutaneous pericardiotomy.

All publications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. The following description includes information that may be useful in understanding the present subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art.
Pericardiocentesis is a procedure wherein the fluid in the pericardium is aspirated. Fluid aspiration is necessary to relieve the pressure on the heart or to analyze the fluid surrounding the heart. Examples of indications for pericardiocentesis include but are not limited to cardiac tamponade, pericarditis, and pericardial effusion. In instances wherein long term drainage is necessary, a cardiothoracic surgeon will create a pericardial window, in which an opening is made in the pericardium to drain the fluid. The procedure is known as a pericardiotomy or pericardiostomy.
Balloon dilation of the pericardium is currently performed with an aortic balloon valvuloplasty catheter. Percutaneous balloon pericardiotomy is a percutaneous procedure using a balloon catheter to produce a pericardial window, in effect, by tearing the pericardium in patients with pericardial effusion. The procedure is typically an alternative to conventional pericardiotomy to avoid surgery in patients with a poor prognosis. Percutaneous pericardiotomy procedures have been performed with a single or double balloon catheter. Generally, the procedure involves having the balloon span across the pericardium and quickly inflating the balloon to create the pericardial window and is performed under fluoroscopic guidance to ensure that the balloon spans across the pericardium and that a pericardial window is created.
Nonetheless, these procedures require fluoroscopic guidance and a highly skilled interventional cardiologist. Thus, there exists a need in the art for a device and a method for percutaneous pericardiotomy that does not require the fluoroscopic guidance and that may be more simple to perform.

Balloon catheter and methods for pericardiocentesis and percutaneous pericardiotomy


A method, system and apparatus for uploading and downloading a caption file are disclosed. The method includes: receiving, by a caption server, file information of a multimedia file and file information of a caption file corresponding to the multimedia file from a client end player; determining, by the caption server, whether the caption server has the caption file according to the file information of the caption file and transmitting a status message indicating whether the caption server has the caption file to the client end player, to enable the client end player to upload the caption file when determining according to the status message that the caption server does not have the caption file. In the solution of the present disclosure, the client end player can upload and download the caption file automatically. The user does not need to search for and download the caption file manually, which improves the user's experience and saves resources of the caption server.

With development of telecommunications, multimedia files become popular and are widely used due to their merits such as transmission and storage convenience and high fidelity.
There are various kinds of multimedia files. Generally, the multimedia files may be classified into several kinds, e.g. voice, image and video. Since different kinds of multimedia files have different creating and playing principles, corresponding client end players should be installed in a client end, e.g. computer, cell phone. When the client end player plays a multimedia file, besides the multimedia file, a caption file corresponding to the multimedia file is generally played.
Popular client end players provide a function of automatically adding the caption file. When a user plays a multimedia file, the client end player automatically adds a caption file in local storage or a designated path. If the multimedia file played by the user does not have a caption file in the local storage, the caption file should be downloaded.
Currently, the method for downloading a caption file is as follows. The user downloads the caption file manually from a network or from other client ends. If the user wants to upload a local caption file to a server when playing a multimedia file, the user needs to manually transmit the local caption file to the server for use of other users.

Method, system and apparatus for uploading and downloading a caption file

Tencent Technology (Shenzhen) Company Limited


The invention provides devices useful for the delivery of active agents to the eye in a controlled manner. In the devices of the invention, the active agent is present within the device in a continuous or discontinuous concentration gradient.

Active agents frequently are administered to the eye for the treatment of ocular diseases and disorders. Conventional means for delivering active agents to the eye involve topical application to the surface of the eye. The eye is uniquely suited to topical administration because, when properly constituted, topically applied active agents can penetrate through the cornea and rise to therapeutic concentration levels inside the eye. Active agents for ocular diseases and disorders may be administered orally or by injection, but such administration routes are disadvantageous in that, in oral administration, the active agent may reach the eye in too low a concentration to have the desired pharmacological effect and their use is complicated by significant, systemic side effects and injections pose the risk of infection.
The majority of ocular active agents are currently delivered topically using eye drops which, though effective for some applications, are inefficient. When a drop of liquid is added to the eye, it overfills the conjunctival sac, the pocket between the eye and the lids, causing a substantial portion of the drop to be lost due to overflow of the lid margin onto the cheek. In addition, a substantial portion of the drop that remains on the ocular surface is drained into the lacrimal puncta, diluting the concentration of the drug.
It is known to use devices that may be inserted into one or more of an orifice of an individual's eye, such as a lacimal punctum, to deliver active agents. One disadvantage of using such devices to deliver agents is that much of the agent may delivered in an initial, large bolus upon insertion of the device into the eye rather than a more linear delivery of the agent over time.

Ophthalmic devices for the controlled release of active agents


According to one embodiment, a system includes a memory comprising instructions, an interface, and a processor communicatively coupled to the memory and the interface. The interface is configured to receive, from a first user associated with an online account, a first request to allow access, by a second user not associated with the online account, to the online account, send, in response to the first request, a second request to the second user for credentials, and receive, in response to the second request, credentials from the second user. The process is configured, when executing the instructions, to generate, for the online account based on the first and the credentials received from the second user, an access profile associated with the second user.

Typically, online accounts may be accessed only by the owner of the account or agents of the company that provides the online account. In certain situations, however, an account owner may wish to allow third parties to access information in the online account or perform functions associated with the online account on behalf of the account owner.

Configuring access to online accounts for third parties not associated with the online account


A technique for reducing information reception delays is provided. The technique reduces delays that may be caused by protocols that guarantee order and delivery, such as TCP/IP. The technique creates multiple connections between a sender and recipient computing devices and sends messages from the sender to the recipient on the multiple connections redundantly. The recipient can then use the first arriving message and ignore the subsequently arriving redundant messages. The recipient can also wait for a period of time before determining which of the arrived messages to use. The technique may dynamically add connections if messages are not consistently received in a timely manner on multiple connections. Conversely, the technique may remove connections if messages are consistently received in a timely manner on multiple connections. The technique can accordingly be used with applications that are intolerant of data reception delays such as Voice over IP, real-time streaming audio, or real-time streaming video.

Transmission Control Protocol ("TCP") is a connection-oriented, reliable delivery transport layer protocol. TCP is typically described as a transport layer that provides an interface between an application layer and a network layer. The application layer generally communicates with the TCP layer by sending or receiving a stream of data (e.g., a number of bytes of data). TCP organizes this datastream into segments that can be carried by the protocol employed at the network layer, e.g., the Internet Protocol ("IP"). These segments are commonly referred to as "packets," "frames," or "messages." TCP and IP are often jointly referred to as TCP/IP. The application, transport, and network layers, together with other layers, are jointly referred to as a data communications stack.
Clients and servers communicate with one another using TCP by establishing a connection between one another. When establishing a connection, a server typically opens a "socket" and listens passively for a connection request from a client. The client requests to open a connection by sending a signal to the server's socket, which the server acknowledges to open the connection. Once a connection is established, the client and server can exchange messages.
TCP guarantees order and delivery of messages by adding or verifying sequence numbers in the messages. The sender of messages adds a sequence number to each message it sends. The receiver of the messages acknowledges delivery of the messages by returning the sequence number of the received messages in acknowledgment messages. When the sender does not receive in a timely manner an acknowledgement for a message it sent, the sender assumes that the message was lost and re-sends the message. In a variation of this method of guaranteeing order and delivery, a "sliding window" of messages may be used. When using a sliding window method, the sender may send multiple messages, each with a different sequence number, without waiting for an acknowledgement for each sent message before sending another message. The sender may then send additional messages after receiving an acknowledgment for one or more messages in the previously sent window, or may re-send messages for which an acknowledgment is not received in a timely manner. Thus, by sending, acknowledging, and verifying sequence numbers, TCP guarantees order and delivery of messages.
When a protocol of a layer of a data communications stack guarantees order and delivery of messages, higher levels of the data communications stack, such as an application or session layer, do not need to be concerned that data will be lost or may arrive in an unintended sequence. As an example, if a client application sends a message to a database server indicating to set a value to 5, then sends a message indicating to set the value to 10, and finally sends a message indicating to multiply the value by 3, the final result would be different depending on whether all messages arrived at the server, and whether they arrived in the intended order. An application using a TCP transport layer can be assured that the final result will be 30, but an application using an alternate transport layer may have no such assurance. Because TCP guarantees order and delivery of messages, it is commonly employed in intranets, the Internet, and other networks employing unreliable lower layers of a data communications stack.
Although TCP guarantees the order and delivery of messages, it does not guarantee the time of delivery. The timing of message delivery can be unpredictable because messages may travel over different network routes, the sender may attempt multiple retransmissions before receiving an acknowledgment, or because of other reasons beyond an application's (or transport layer's) control. As a result, the difference in time between two received messages may be substantially greater than the difference between the times the messages were sent.
These delays may create problems for some types of applications. As an example, client applications that receive audio (e.g., "voice over IP" or streaming audio) or video (e.g., streaming video) from a server may need to receive messages containing the audio or video without significant delays between the messages. Otherwise, a listener or viewer may perceive gaps in the received audio or video information. When applications desire to minimize or eliminate such delays, they may use a transport protocol other than TCP. However, these other transport protocols may not guarantee order and delivery. Moreover, these other transport protocols may not be as commonly employed as TCP, and so messages sent using these transport protocols may not be capable of being distributed as widely as when sent using TCP.
A technique for using protocols that guarantees order and delivery, such as TCP, to deliver data to applications that have a low tolerance for delays would thus have significant utility.


Disclosed is an audio output control method and an electronic device supporting the same. The audio output control method includes determining an output of an audio processing unit decoding an audio source signal, and controlling generating of a reference signal to be supplied to an audio output unit in response to an output of the audio processing unit.

1. Field of the Invention
The present invention generally relates to audio output.
2. Description of the Related Art
The use of mobile electronic devices has become widespread due in large part to the small size of such devices. Many conventional electronic devices support an audio source reproduction function for playing an audio source that is selected in response to an audio source reproduction request.
However, the conventional electronic device outputs an audio signal that includes noise due to various factors while the played audio source is output. Accordingly, there is a need in the art for an audio source reproduction function for playing an audio source while eliminating the factors creating noise in the conventional electronic device.

Audio output control method and electronic device supporting the same


A memory managing method for a non-volatile memory and a controller using the same are disclosed. The controller includes a system wear leveling member for performing a first wear leveling process in a non-volatile memory for choosing a memory unit; and a subsystem wear leveling member for performing a second wear leveling process in the chosen memory unit for selecting a block from the chosen memory unit for data programming; whereby uneven use of the blocks of the chosen memory unit is avoided.

The use of non-volatile memory systems such as flash memory storage systems is increasing due to the compact physical size of such memory systems and the ability for non-volatile memory to be repetitively reprogrammed. The compact physical size of flash memory storage systems facilitates the use of such storage systems in devices which are becoming increasingly prevalent. Devices which use flash memory storage systems include, but are not limited to, digital cameras, digital camcorders, digital music players, handheld personal computers, and global positioning devices. The ability to repetitively reprogram non-volatile memory included in flash memory storage systems enables flash memory storage systems to be used and reused.
In general, flash memory storage systems may include flash memory cards and flash memory chip sets. Flash memory chip sets generally include flash memory components and a controller. Typically, a flash memory chip set may be arranged to be assembled into an embedded system. The manufacturers of such assemblies or host systems typically acquire flash memory in component-form, as well as other components, and then assemble the flash memory and the other components into a host system.
Although non-volatile memory or, more specifically, flash memory storage blocks within flash memory systems may be repetitively programmed and erased, each block or physical location may only be erased a certain number of times before the block wears out, i.e., before memory capacity begins to become smaller. That is, each block has a program and erase cycle limit. In some memories, a block may be erased up to approximately ten thousand times before the block is considered to be unusable. In other memories, a block may be erased up to approximately one hundred thousand times or even up to a million times before the block is considered to be worn out. When a block is worn out, thereby causing a loss of use or a significant degradation of performance to a portion of the overall storage volume of the flash memory system, a user of the flash memory system may be adversely affected, as for the example through the loss of programmed data or the inability to program data.
The wear on blocks, or physical locations, within a flash memory system varies depending upon how much each of the blocks is programmed. If a block or, more generally, a storage element, is programmed once, then effectively never reprogrammed, the number of program and erase cycles and, hence, wear associated with that block will generally be relatively low. However, if a block is repetitively written to and erased, e.g., cycled, the wear associated with that block will generally be relatively high. As logical block addresses (LBAs) are used by hosts, e.g., systems which access or use a flash memory system, to access data programmed in a flash memory system, if a host repeatedly uses the same LBAs to write and overwrite data, the same physical locations or blocks within the flash memory system are repeatedly written to and erased, as will be appreciated by those of skill in the art.
When some blocks are effectively worn out while other blocks are relatively unworn, the existence of the worn out blocks generally compromises the overall performance of the flash memory system. In addition to degradation of performance associated with worn out blocks themselves, the overall performance of the flash memory system may be compromised when an insufficient number of blocks which are not worn out are available to program desired data. Often, a flash memory system may be deemed unusable when a critical number worn out blocks are present in the flash memory system, even when many other cells in the flash memory system are relatively unworn. When a flash memory system which includes a substantial number of relatively unworn blocks is considered to be unusable, many resources associated with the flash memory system are effectively wasted.
In order to increase the likelihood that blocks within a flash memory system are worn fairly evenly, wear leveling operations are often performed. Wear leveling operations, as will be understood by those skilled in the art, are generally arranged to allow the physical locations or blocks which are associated with particular LBAs to be changed such that the same LBAs are not always associated with the same physical locations or blocks. By changing the block associations of LBAs, it is less likely that a particular block may wear out well before other blocks wear out.
Recently, non-volatile memories, having data transmitted in a group of blocks at once, are rapidly developing due to the fact that such non-volatile memory has an access speed faster than a traditional non-volatile memory which transmits data one block at a time. In other words, data in such non-volatile memory is accessed in the unit of memory units rather than blocks, and thus the access speed is increased. Hence, data is also erased in the unit of memory units. However, unused blocks of a memory unit may be erased concurrently and uneven use of the blocks of the memory unit may occur. Therefore, a subsystem wear leveling method for a non-volatile memory and a controller using the same are desperately desired so as to prolong a lifespan of the non-volatile memory.

Memory managing method for non-volatile memory and controller using the same


The invention provides a remote control device with password functions. Control function buttons can be used for sending control signals and for password entry. The remote control device is configured such that a user can enable and disable a password mode. When the password mode is enabled, the remote control is configured to require a password being entered using one or more control function buttons before a control signal will be transmitted in response to a control function being pressed or disabling the password mode. A user can also invoke a password programming function to enter, change or erase a password using one or more control function buttons.

Remote control devices (often simply referred to as remote control) have been widely used nowadays for many applications, from controlling audio video equipment, lighting to access control such as opening and closing a garage door, locking and unlocking a deadbolt lock, even arming and disarming an alarm system. Some of these applications involve security measure. For example, a garage door remote control for opening a garage door, a remote control for unlocking a door, or a remote control for arming and disarming an alarm system. Most of the remote controls can be accessed by any user simply by pressing the designated buttons. Gaining access to such a remote control generally means gaining access to the controlled security device. Therefore, it is desired to have additional security measure to these remote controls so that not everyone having physical access to a remote control device can activate the remote control device or the controlled device.
It is an object of the present invention to mitigate or obviate at least one of the above mentioned disadvantages.

Remote control device with password functions


A steering system for a work vehicle adjusts the steering ratio in response to changes in the speed of the work vehicle.

As used in this application, the steering ratio is defined as steering output/steering input. The steering input may be, for example, displacement of a joystick or a steering wheel. The steering output may be, for example, change in the steered position of one or more steerable elements (e.g., an articulated section of the vehicle and/or traction elements, such as wheels, of the vehicle), and/or change in the actuator(s) (e.g., hydraulic cylinder(s)) for effecting such change in the steered position of the one or more steerable elements. A larger steering ratio represents a steering system in which a given steering input results in a relatively large steering output whereas a smaller steering ratio represents a steering system in which the given steering input results in a relatively small steering output. Thus, the steering output of a steering system with a larger steering ratio is more "sensitive" to the steering input than a steering system with a smaller steering ratio. Such sensitivity could be particularly noticeable in vehicles set at a higher steering ratio and traveling at relatively high speed.

Work vehicle steering system with flow-metering curve selection and associated method