A mineral water composition comprising a blend of minerals and trace elements, a bifidobacterium probiotic agent, at least one carboxylic acid, and at least one mineral acid. Embodiments of the composition further comprises silica and ascorbic acid. The mineral water compositions can be ingested as a concentrate or diluted into beverages or other foods.

The present invention relates generally to a consumable mineral water composition containing a blend of minerals and trace elements, a probiotic agent that selectively promotes growth of bifidobacterium over other intestinal flora, and further contains a mineral acid and a carboxylic acid; and may further contain ascorbic acid and silica.
The need for minerals and trace elements are well known in the nutritional and holistic arts. Potassium, sodium, calcium, and magnesium ions are the predominant metal ions in the cytoplasm of a cell. Many of these minerals and trace elements are used as cofactors, activators, or stabilizers bound to enzymes, proteins, nucleic acids or other biochemicals. Calcium ion combines with phosphate ion to comprise bone matrix. Iron is at the center of a heme group that make up hemoglobin, a metalloprotein that binds oxygen for respiration. Magnesium or manganese ion binds with adenosine triphosphate (ATP) to form the absolutely required substrate used in most ATP-dependent enzymatic reactions. The trace element selenium is required by the enzyme superoxide dismutase for effective catalysis. Fluoride binds to the enamel of your teeth, thereby inhibiting tooth decay. Iodine is another trace element needed for proper function of the thyroid gland. Silicon is an essential element required for normal growth development, especially with bones and connective tissue (Nielsen, F. H. in Prasad, A. S., ed. Essential and Toxic Trace Elements in Human Health and Disease: An Update:355-376. New York: Wiley-Liss, 1993).
Proper intestinal health, such as that brought on by certain intestinal microorganisms, helps the intestine to absorb those minerals and trace elements that the body minimally requires. Without a healthy intestine, the body often reacts with diarrhea that not only depletes water from the system, thereby creating dangerous levels of dehydration, but also a loss of minerals and trace elements. A substantial loss of electrolytes during diarrhea can cause death.
Bifidobacteria are one component of the intestinal flora of man and other mammals. These bacteria are not pathogenic, but are known to inhibit other pathogenic, intestinal bacteria because of their ability to produce acetic acid, lactic acid, and propionic acid, a known antimicrobial. They are also known to produce bioactive compounds that provide protective health benefits to their hosts. It is well known in the art that having a dominating culture of bifidobacteria in the intestine can improve health. For instance, it has been noted that breast-fed neonates have mostly pure cultures of bifidobacteria in their intestines and are therefore less susceptible to enteral infection compared to bottle-fed neonates that have sparse populations of bifidobacteria. Other U.S. patents (Brassart, et al., U.S. Pat. No. 5,494,664, issued Feb. 27, 1996) have proposed ingestion of pure cultures of Bifidobacteria species to establish and maintain proper intestinal health. Some have proposed that bifidobacteria have an immuno-potentiating effect, and a prophylactic effect that arises from the competitive microbial exclusion that results in a decreased production of toxins and carcinogenic substances from pathogenic bacteria.
There is a need to promote the growth of intestinal bifidobacteria, so that the potential health-inducing effects can be exploited by the users. This has fueled the need for continuing research in the field of chemicals and conditions, essentially xe2x80x9cbifidus growth factorsxe2x80x9d that encourage the preferential growth of intestinal bifidobacteria.
The two recognized requirements for a bifidus growth factor are that it: 1) not be digested and absorbed in the upper digestive tract but reaches the ileum and large colon, where the bifidobacteria are located; and, 2) that it be efficiently metabolized by bifidobacteria and under-utilized or not utilized by other intestinal bacteria. Most prior work on bifidus growth factors has focused on the use and incorporation of oligosaccharides, specifically fructo-oligosaccharides, into various kinds of foodstuffs and drinks.
However, oligosaccharides have not generally fulfilled the requirements for a bifidus growth factor. For instance, fructo-oligosaccharides have the disadvantage that they are broken down by stomach acids (hydrochloric acid) and are partly absorbed in the small intestines. Other candidates, such as isomalto-oligosaccharides are mostly digested and absorbed in the small intestine prior to reaching the bifidobacterium resident in the colon. Conversely, galacto-oligosaccharides are mostly undigested and unabsorbed prior to the colon, but instead suffer from economic disadvantages relating to high production costs resulting from low manufacturing yields, thereby becoming commercially nonviable.
The low selectivity of bifidobacterium for all three of the aforementioned oligosaccharides relative to their utilization by the other intestinal flora is not ideal. As a result, there must be a large intake of oligosaccharides to achieve the desired effect upon the bifidobacteria in the colon. Thus, the growth of bifidobacteria varieties and competing bacteria is promoted simultaneously, resulting in a less than optimum ratio of bifido to other species. This situation has created a need for a better probiotic agent to selectively promote the growth of bifidobacteria in the alimentary tract.
In the instant invention, the concept of using a mineral water blend combined with a selective bifidobacterium probiotic agent to improve intestinal, as well as overall health is believed to be novel.
There is therefore a need to provide a new composition comprised of a mineral water blend and a bifidobacterium probiotic agent that overcomes the problems of prior agents, which problems include selectivity of the agent over other intestinal flora, limiting digestion, and absorption of the agent in the upper digestive tract.
An object of the invention is to provide beverages comprising minerals and trace elements, along with a selective bifidobacterium probiotic agent to provides continuing mineral and trace element nutrition and intestinal health to those who consume it.
Another object of the invention is to provide compositions which are additive to beverages and foods for man and other animals.
It is an object of the present invention to provide a combination of mineral ions, mineral and trace element complexes, as well as a bifidobacterium probiotic agent that together promote the well being of the user, by allowing the uptake of acidic vitamins, and the uptake of silicon in the form of a silica dioxide.
It is another object of the present invention to maintain the solubilization of the minerals and trace elements, by including chemical agents that chelate or complex the ions in solution, thereby preventing precipitation, and enhancing absorption.
It is still another object to provide a new beverage containing the mineral water blend and bifidobacterium probiotic agent that can be used with a variety of different carriers and foodstuffs.
It is yet another object of the present invention to provide a means for providing both concentrates and dilutions of the beverage or composition over a wide range of concentrations.
It is still yet another object of the present invention to provide for an inexpensive composition that is simple, user-friendly, requires minimal preparation, and that can be freely utilized across a broad range of carriers and foods.
The aforementioned background has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention as will be described. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the following written disclosure of the Detailed Description of the Invention.
The present invention is directed to dietary mineral composition comprising a health promoting dose of a mineral and trace element blend combined with a bifidobacterium probiotic agent. The concentration range of the chemical components in the preferred embodiment are: from about 1% w/w to about 10% w/w of a bifidobacterium probiotic agent; from about 10% w/w to about 90% w/w of a edible, water soluble composition of mineral salts and trace elements, preferably 44% w/w or 83% w/w of TRASEA 19; from about 0.1% w/w to about 10% w/w of a carboxylic acid, preferably a tricarboxylic acid such as 3% w/w citric acid; and from about 0.1% w/w to about 20% of a mineral acid, preferably 8% w/w sulfuric acid.
An alternative composition is further comprised of: from about 0.1% w/w to about 10% w/w of an amorphous silica dispersion, colloidal silica dispersion of aggregated silica, or colloidal dispersion of crystalline silica, where the amorphous spherical particle size ranges from about 4 nm to about 100 nm, preferably 10 nm; and from about 0.001% w/w to about 1% w/w of an acidic vitamin, preferably 0.01% w/w ascorbic acid.
Both the preferred and alternative embodiments may be further comprised of: from about 0.001% w/w to about 0.1% w/w of an acidic protease enzyme, preferably 0.01% w/w pepsin for the preferred embodiment, and preferably 0.005% w/w pepsin for the silica containing alternative embodiment; from about 0.02% w/w to about 2% w/w of a protein or peptide digest, preferably 0.2% w/w PolyPro 5000(copyright) hydrolyzed collagen or 0.1% w/w N-Z-Amine(copyright) enzymatic hydrolysate of milk protein (casein digest); from about 0.0005% w/w to about 0.05% w/w each of three amino acids, preferably 0.005% w/w each of the L-isomers of arginine, carnitine and ornithine; from about 0.005% w/w to about 0.5% w/w of acidulant vinegar, preferably 0.025% w/w or 0.05% w/w of rice vinegar; and from about 0.015% w/w to about 1.5% w/w of a preservative, preferably 0.15% w/w/ sodium benzoate.
Either embodiment is in a form mixable with a carrier, to form a beverage. The carrier can be water, fruit juices, teas, dairy products, alcoholic drinks, sodas, electrolyte replacement solutions, and other edible liquids. The composition can be orally consumed by the user as a concentrate directly, or consumed as a dilution (e.g. as a beverage), wherein the dilution factor ranges from about 1:2 to about 1:10,000 or to the taste of the individual consumer. The concentrate may be added, i.e. diluted to solid or semi-solid (e.g. sauces) foodstuffs. The present invention is contrary to other bifidobacterium promoting art, which usually place the bifidobacteria directly into the food; see Kurmann et al., xe2x80x9cBifidobacteria in Foodsxe2x80x9d, Encyclopedia of Food Science, Food Technology and Nutrition, (1993); or Hughes et al., xe2x80x9cBifidobacteria: Their Potential For Use In American Dairy Productsxe2x80x9d, Food Technology (April 1991).
Among the utilities of the present invention, the compositions of the present invention are compositions useful for establishing and maintaining a healthy digestive system by reducing pathogenic microorganisms and their toxins, thereby allowing edible co-consumed mineral and trace elements to be absorbed by the intestines. Such composition are combinations of mineral water blends, bifidobacteria probiotic agents, and various acidulants, acidic vitamins, mineral chelators, complexors or binders that facilitate the absorption of these minerals and elements by the intestines. Such combinations may be in any form suitable for mixing with a liquid to form the mineral/trace element/bifidobacteria probiotic agent/water soluble combination or suspension for oral consumption. The preferred form is a concentrate from which several drops are dispensed which readily mix and disperse in any liquid beverage, or may be sprinkled over or mixed with other solid or semi-solid foodstuffs. Suitable beverages include but are not restricted to any beverage suitable for human consumption such as water, seltzers, fruit juices, artificially-flavored fruit drinks, vegetable juices, brewable teas, instant teas, green teas, milk, dairy liquids, dairy products, dairy drinks, soy products, soy drinks, soy sauce, liqueurs, wines, wine coolers, alcoholic liquids, electrolyte replacement solutions, carbonated sodas, soft drinks, infant formula, mother""s milk and other drinkable liquids and solutions.
The levels of edible mineral water blend and bifidobacteria probiotic agent disclosed herein are based on a chemically and dietetically compatible, palatable concentration of a commercially available trace mineral water dietary supplement, from about 10% w/w to about 90% w/w. The units of % w/w are defined as xe2x80x9cgrams of component addedxe2x80x9d per xe2x80x9c100 grams of total components added.xe2x80x9d
Also included in the present invention are compositions which vary in delivered amount of minerals and trace elements, or amount of bifidobacteria probiotic agent, or both. Such compositions may be formulated by varying the weight of any single chemical components in proportion to the total weight of all components disclosed herein.
The components of the compositions according to the present invention, and representative amounts, are described in detail as follows.
Mineral Water
Mineral waters or mineral water blends for use in the compositions of the invention are preferably derived from marine, terrestrial, or fresh water sources and contain a substantial number of dissolved minerals and trace elements. Of the approximate 80 elements found in such water, about 24 are essential for proper nutrition and health. Mineral water blends are commercially available in specialty nutrition stores, and are well known to those skilled in the art. One commercial example is TRÃSEA(trademark) 19 manufactured by Nutritional Engineering, Inc. of Carlsbad, Calif., which is a refined mineral and trace element water taken from the Pacific Ocean. TRÃSEA(trademark) 19 and other mineral waters generally contain about 37 detectable minerals and elements. Other elements may be present in the mineral water, but are below the detectable concentration of the chemical quantization method. The concentration range for a mineral water blend, such as TRÃSEA 19 in the present invention and embodiments is from about 10% w/w to about 90% w/w, with a preferred concentration of about 83% w/w in the preferred embodiment, and about 44% w/w in an alternative embodiment containing silica. It should be understood that synthetic mineral water blends which mimic water blends of marine, fresh water, or terrestrial sources also find use in the compositions of the invention. Methods for making synthetic mineral water blends are well known in the art, for example, in the art of making salt water trace mineral blends for marine aquaria.
Table 1 illustrates a typical chemical analysis of TRÃSEA(trademark) 19 with concentrations of detectable component minerals and elements stated in units of parts per million (ppm, milligrams per liter).
Bifidobacteria Probiotic Agents
In the compositions of the invention, gluconic acid, lactone derivatives and salts thereof represent the preferred sugar acid, or more specifically a monosaccharide sugar acid acting as a bifidobacterium probiotic agent. Gluconic acid (which is one of several structurally similar aldonic acids, salts of aldonic acids, or lactones of aldonic acids) is the only known member of this group which possesses bifidobacterium probiotic activity. These compounds are chemically similar to ketonic acids, salts of ketonic acids and lactones of ketonic acids. It is understood that compounds which have bifodobacterium probiotic activity are included in the scope of bifidoprobiotic agents for use in the compositions of the invention.
Gluconic acid is added to the mineral water blend in the lactone derivative form as glucono-delta-lactone, a precursor that converts to gluconic acid when aqueous. As described in Asano et al., U.S. Pat. No. 5,605,697, gluconic acid, its salts and lactone derivatives such as glucono-delta-lactone, are the xe2x80x9cbifidus factorsxe2x80x9d, the sugar acids that promote growth of bifidobacterium with good selectivity over other intestinal microbes. U.S. Pat. No. 5,605,697 is expressly incorporated herein by reference. Gluconic acid and glucono-delta-lactone are both commercially available from Sigma Chemical Company, St. Louis, Mo. The concentration range for glucono-delta-lactone in the present invention and embodiments is from about 1% w/w to about 20% w/w, with a preferred concentration of about 6% w/w in the preferred embodiment, and 3% w/w in the silica-containing alternative embodiment.
Fructo-oligosaccharides are a type of fructosyl-containing oligosaccharides. As used herein the term xe2x80x9cfructosyl-containing oligosaccharidexe2x80x9d is meant to include rearrangement products resulting from the method of the invention described in Whistler et al., U.S. Pat. No. 5,843,922 issued Dec. 1, 1998. Such rearrangement products include, without limitation: 1-kestose, 6-kestose, neokestose, fructo-oligosaccharides, difructose dianhydrides, fructosans, fructoglucans, and mixtures thereof. For all that it teaches about xe2x80x9cfrutosyl-containing oligosaccharidesxe2x80x9d, their manufacture, and their use in promoting the growth of bifidobacteria, the disclosure of U.S. Pat. No. 5,843,922 is expressly incorporated herein by reference. The concentration range for fructo-oligosaccharides in the present invention and embodiments is from about 1% w/w to about 20% w/w, with preferred concentrations of about 3 or 6% w/w.
Carboxylic Acids
Edible carboxylic acids complex or bind to the some of the mineral ions and trace elements thereby buffering the minerals during digestion and assimilation in the intestines. Monocarboxylic acids weakly associate with the mineral ions, while di- and tricarboxylic acids actually chelate to the mineral ions. Chelate formation occurs when a metal ion is bound to two or more donor atoms in a single ligand, such as with di- or tri-carboxylic acids. Representative dicarboxylic acids are alpha-ketoglutarate, succinate, fumarate, malate, oxaloacetate, their salts and derivatives. Representative tricarboxylic acids are citrate, cis-aconitate, isocitrate, their salts and derivatives. The concentration range for a carboxylic acid, such as citric acid (which is preferred) in the embodiments of the present invention is from about 0.1% w/w to about 10% w/w, with a preferred concentration of about 3% w/w.
Strong Acidulant: Mineral Acids
Mineral acids are used to acidify the compositions of the present invention, and are all commonly available from chemical supply houses, including Sigma Chemical Company, St. Louis, Mo. These mineral acids must meet Food Chemical Codex (FCC) U.S. Pharmacopea (USP) or National Formulary (NF) specifications. Mineral acids that meets these requirements are sulfuric acid, phosphoric acid, hydrochloric acid and nitric acid. Sulfuric and phosphoric are preferred in the compositions of the invention. The concentration range for a mineral acid in the present invention and its embodiments are from about 0.1% w/w to about 20% w/w, with a preferred concentration of about 8% w/w.
Acidic Vitamins
The only acidic vitamin used in the compositions of the present invention is ascorbic acid (vitamin C), its ascorbate salts, isomers and derivatives. Vitamin C is contained in the invention because it is an edible acid and its immunostimulant derivatives play an important part in cell regulation. It is also able to complex or bind to some of the mineral ions from the mineral water blend, thereby contributing to the solubilization of the minerals, and mineral absorption by the intestines. Ascorbic acid, its salts, isomers and derivatives are commercially available from Sigma Chemical Company of St. Louis, Mo. The concentration range for ascorbic acid in the present invention is from about 0.001% w/w to about 1% w/w, with a preferred concentration of 0.01% w/w.
Silicon and Silica
Dietary silicon promotes proper growth and strong bones and connective tissue (Nielsen, F. H. in Prasad, A. S., ed. Essential and Toxic Trace Elements in Human Health and Disease: An Update:355-376. New York: Wiley-Liss, 1993). A novel aspect of the present invention involves a composition which overcomes the absorbtive barrier of the intestine to the delivery of nutritional silica. The compositions of the present invention deliver bioavailable silica in a stable, colloidally dispersed form via absorption through the intestine. Orally administering the compositions of the invention to humans or animals is the basis for a method of the invention for delivering bioavailable or bionutrient silica.
Particles of colloidal silica dispersions are commercially available as NYACOL(copyright) 830 Colloidal Silica from Eka Chemicals of Marietta, G., as well as other vendors (e.g. DuPont, Nalco, Huls). This silica is an alkaline, aqueous dispersion of colloidal silica at a 30% concentration. The Grade 830 dispersed silica is present as amorphous spheres, 10 nm in size. The particles carry a slightly negative surface charge and have a high surface area-to-weight ratio. NYACOL(copyright) 830 is an opalescent liquid, slightly more viscous than water. An alternative embodiment of the present invention contains a dispersion of NYACOL(copyright) colloidal silica particles having a spherical size range of from about 4 nm (Grade 215) to about 100 nm (Grade 9950), with a preferred spherical particle size of 10 nm (Grade 830). The silica delivery system of the invention, i.e. the compositions comprising silica disclosed herein, is based on the advantageous use of colloidal silica, which as a very low charge density per unit particle. The low charge density prevents or minimizes the aggregation or crystallization of the silica, thus providing a system for absorptive delivery of bionutrient silica through the intestine. This delivery system of the invention overcomes the barrier to absorption of bionutrient silica caused by charges that form on these small silica particles, especially in an acid environment, which allows the particles to aggregate and form what are termed colloids or aggregations, which are not absorbed or minimally absorbed through the intestine.
The concentration range for silica in the silica-containing alternative embodiment is from about 0.1% w/w to about 8% w/w, with a preferred concentration of 1.8% w/w.
In addition to silica derived from the herb horse tail, another biological source of colloidal silica for use in the compositions and methods of the invention is reported in CandEN, Nov. 8, 1999, p. 19, and involves the use of peptides extracted from the cells walls of diatoms to generate networks of silica nonospheres. Recombinant organisms comprising the genetic determinants of these peptides is also contemplated as a source of silica for use in the present invention.
Amino Compounds
As used herein, the term xe2x80x9camino compoundsxe2x80x9d refers to amino acids, peptides, oligopeptides, proteolytic digestion products of proteins, and proteins.
Acidic Proteases: The preferred acidic protease for use in an embodiment of the invention is pepsin. It is the principal proteolytic enzyme of vertebrate gastric juice. Its inactive zymogen precursor, pepsinogen is produced in the stomach mucosa. Pepsinogen activates to pepsin below pH 5, which is easily achieved in the present invention. Therefore pepsinogen could be substituted for pepsin, and it would quickly convert to pepsin upon dissolution in this acidified mineral water composition. The optimal pH for pepsin is about 1.0 for native substrates such as casein or hemoglobin. The source of this pepsin is from porcine stomach mucosa, and it is commercially available from Sigma Chemical Company of St. Louis, Mo. Pepsin, which is amino compound (as defined above) is a proteolytic enzyme tolerant to low pH, thereby assisting in the digestive process located in the intestines. The concentration range for pepsin in the preferred embodiment is from about 0.001% w/w to about 0.1% w/w, with a preferred concentration of 0.01% w/w of pepsin. The concentration range for pepsin in the alternative silica embodiment is from about 0.0005% w/w to about 0.05% w/w, with a preferred concentration of 0.005% w/w of pepsin.
Protein or Peptide Digests
The preferred protein or peptide digests are PolyPro 5000(trademark) for the preferred embodiment, and N-Z-Amine(trademark) for the silica containing alternative embodiment comprising ascorbic acid and a dispersion of amorphous spherical silica particles. PolyPro 5000(trademark) is hydrolyzed collagen comprised of peptides with an average molecular weight of 5000 daltons and amino acids. N-Z-Amine(trademark) is a digest of enzymatically hydrolyzed casein protein (milk protein). The function of the protein or peptide digests is to provide solubilizers to minimize trace mineral precipitation and to enhance transport of trace minerals across the cell membranes of intestinal villi and into the bloodstream.
These protein digests are utilized as a nutrient media for the bacteria resident in the large intestine, and to improve the texture and palatability of the composition. These edible protein digests are also useful for the formation and maintenance of bone, skin and cartilage. PolyPro 5000(trademark) is commercially available from Leiner Davis Gelatin of Davenport, Iowa. N-Z-Amine(trademark) is commercially available from Quest International (Hoffinan Estates, Ill.). In the embodiments of the invention, PolyPro 5000(trademark) has a concentration range of from about 0.02% w/w to about 2% w/w, with a preferred concentration of 0.2% w/w in the preferred embodiment. N-Z-Amine(trademark) soluble peptide composition is utilized at a concentration range from about 0.01% w/w to about 1% w/w, with a preferred concentration of 0.1% w/w in the silica containing alternative embodiment.
Amino Acids
The amino acids blended into alternative silica embodiments of the present invention are the L-isomers of arginine, ornithine and carnitine. Their respective chemical structures are: H2Nxe2x80x94C(xe2x95x90NH)xe2x80x94NHxe2x80x94(CH2)3xe2x80x94CHxe2x80x94(NH2)xe2x80x94COOH; NH2xe2x80x94CH(xe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94NH2)xe2x80x94COOH); and (CH3)3xe2x80x94Nxe2x80x94CH2xe2x80x94CH(OH)xe2x80x94CH2xe2x80x94COOH. These three amino acids are included because of their ability to complex or bind the minerals or elements contained in the alternative silica compositions, and for their role in the formation and maintenance of bone, skin and cartilage. All three of these amino acids are commercially available from Sigma Chemical Company. They all have a concentration range of about 0.0005% w/w to about 0.005% w/w, with a preferred concentration of 0.005% w/w.
Mild Acidulants
Mild Acidulants are used to gently acidify a food stuff or liquid during preparation. The acidulants in embodiments of the invention include but are not restricted to vinegar, rice vinegar, white vinegar, derivatives of vinegar, concentrates and dilutions thereof. Rice vinegar is the preferred acidulant, and is thought to have special nutritive properties in several cultures. These vinegars are available from common supply houses. The concentration range for this acidulant is from about 0.005% w/w to about 0.5% w/w, with a preferred concentration of 0.05% w/w.
Food Grade Preservatives
Any food grade preservative may be used in the compositions of the invention. Preferred preservatives used in these embodiments of the present invention are benzoic acid, benzoate salts such as sodium benzoate, and derivatives of benzoic acid. Examples of derivatives are propylparaben, and methylparaben. The role of these preservatives are to inhibit microbial growth in the mineral water blend / bifidobacterium probiotic agent. All of these preservatives are commercially available from Sigma Chemical Company. They can be used over a broad concentration range from about 0.015% w/w to about 1.5% w/w, with a preferred concentration of 0.15% w/w.
Carriers
The present invention may be diluted with one or more carriers, preferably beverages. Suitable carriers must be safe for oral administration to humans, and may be chosen by one of ordinary skill in the art as appropriate for this composition and use intended for the product.
A carrier is a liquid that the compositions of the present invention may be added to, and/or substantially homogeneously diluted or mixed into. Most carriers are common drinks and liquids, and when mixed with the present invention the result is a beverage containing the mineral and trace elements, bifidobacterium probiotic agent, citric acid, sulfuric acid. When mixed with the embodiment comprising silica, the beverage further comprises silica and ascorbic acid.
Suitable carriers herein, depending on desired properties and intended end use, are selected from one or more of the following carriers, which include but are not restricted to water, seltzers, fruit juices, artificially-flavored fruit drinks, vegetable juices, brewable teas, instant teas, green teas, milk, dairy liquids, dairy products, soy products, soy sauce, beers, liqueurs, wines, wine coolers, alcoholic liquids, electrolyte replacement solutions, carbonated sodas, soft drinks, and other drinkable liquids and solutions.
The concentrate of the present invention is added to the carrier so as to make a dilution from about a factor of 1:2 to about a factor of 1:10,000, or in quantities sufficient to achieve desired formulation characteristics according to the formulator""s preference.
Method of Preparation and Use
The method of preparation and use comprises a step of blending into a mineral water blend at least one carboxylic acid, preferably citric acid; a bifidobacteria probiotic agent, such as a sugar acid, preferably gluconic acid or glucono-delta-lactone (which converts to gluconic acid when aqueous); and at least one mineral acid, preferably sulfuric acid to form a second blend. The silica-containing alternative embodiment, which further comprises an acidic vitamin, preferably ascorbic acid, and a silica dispersion, preferably of NYACOL(copyright) 830 Colloidal Silica., is formed in a further blending step which involves mixing into the second blend in any order ascorbic acid or derivatives, and salts thereof and a silica dispersion.
Either of these composition embodiments are then administered in a xe2x80x9csafe and effective amountxe2x80x9d to the subject or user, preferably administered orally as a nutritional supplement. The term xe2x80x9csafe and effective amount,xe2x80x9d as used herein, means an amount of the mineral water composition sufficient to significantly and positively promote the bifidobacterium culture in the subject""s colon, thereby maintaining or improving the health of the colon and digestive system, so that mineral and trace elements are properly absorbed as needed, but low enough to avoid serious side effects at a reasonable benefit/risk ratio. The safe and effective amount will vary with age and physical condition of the user, the nature of the digestive condition, the current number and mix of intestinal bacteria, the duration of the treatment, the nature of concurrent therapy.


The present invention relates to a composite of cerium, zirconium and samarium components, a catalyst composition containing such composite and the use of the catalyst composition for the treatment of a gas stream to reduce contaminants contained therein. The catalyst composition has the capability of substantially simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides.

1. Field of the Invention
The present invention relates to a composite of cerium, zirconium and samarium components and to a catalyst composition containing such composite as well as the use of such catalyst composition for the treatment of a gas stream to reduce contaminants contained therein. More specifically, the present invention is concerned with catalyst compositions containing such composite of the type generally referred to as three-way conversion or xe2x80x9cTWCxe2x80x9d and a process of substantially simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides present in gas streams, particularly exhaust gas streams produced by internal combustion engines.
2. Discussion of Related Art
Three-way conversion catalysts (TWC) have utility in a number of fields including the treatment of exhaust gas streams from internal combustion engines, such as automobile, truck and other gasoline-fueled engines. Emission standards for unburned hydrocarbons, carbon monoxide and nitrogen oxide contaminants have been set by various governments and must be met by older as well as new vehicles. In order to meet such standards, catalytic converters containing a TWC catalyst are located in the exhaust gas line of internal combustion engines. Such catalysts promote the oxidation by oxygen in the exhaust gas stream of unburned hydrocarbons and carbon monoxide as well as the reduction of nitrogen oxides to nitrogen.
It is well know that by the time engine exhaust gases travel from the outlet of the exhaust manifold through an exhaust pipe to a catalytic converter, the gases cool significantly relative to the temperature at or near the manifold, so that there is a significant period of a low rate of conversion of the pollutants in the exhaust gas stream before the exhaust gases heat the catalyst in the catalytic converter to its light-off temperature. Accordingly, during the cold start period of engine operation, there is a significant discharge of engine exhaust gas containing a relatively high amount of pollutants.
It is also well known in the art to reduce the level of pollutants in the exhaust gas stream, particularly the level of hydrocarbons and carbon monoxide, by using an air pump in conjunction with the engine to help oxidize such pollutants. However, vehicle manufacturers would prefer to avoid using mechanical pollution control devices such as air pumps which, with their associated plumbing and mechanical parts, affect the engine architecture and are difficult to control without having an adverse impact on the optimum performance of the engine. Accordingly, vehicle manufacturers would prefer, if at all possible, to tune the engine for optimum performance without using mechanical types of a pollution control device and instead meet the vehicle emission standards discussed below solely with the use of catalyst members. As discussed below, increasingly stringent governmental emission standards require, however, that cold-start emissions be reduced.
The current xe2x80x9cLEVYxe2x80x9d (low emission vehicle) standards in effect for all states other than California prohibit vehicle emissions above 0.08 gram of non-methane hydrocarbons per mile, 3.4 grams of carbon monoxide per mile and 0.2 gram of NOx (nitrogen oxides) per mile. Many vehicle manufacturers have difficulty in meeting the current standards solely with the use of available upstream and/or downstream catalyst compositions without the concurrent use of additional mechanical devices such as air pumps. Of even greater concern is the fact that the California Air Resource Board (xe2x80x9cCARBxe2x80x9d)has promulgated new xe2x80x9cULEVxe2x80x9d (ultra-low emission vehicle) standards that will prohibit vehicle emissions above 0.04 gram of non-methane hydrocarbons per mile, 1.7 grams of carbon monoxide per mile and 0.2 gram of NOx per mile. Moreover, based on historical trends in vehicle emission standards, it is likely that the new ULEV standards will be required nationwide within a few years. Unless an effective method of meeting the new ULEV standards can be rapidly developed and implemented, vehicle manufacturers face the difficult problem of achieving such standards without significant changes in engine/exhaust architecture, incorporation of additional mechanical pollution control devices and the use of large amounts of expensive precious metal-based catalyst systems.
For most vehicles, a large portion (i.e., up to about 80%)of the hydrocarbon emissions occurs during the first phase of the U.S. Federal Test Procedure (xe2x80x9cFTPxe2x80x9d), which encompasses the cold-start period of engine operation, and which requires simulation of cold-start, warm-up, acceleration, cruise, deceleration and similar engine operating modes over a specified time period. A variety of technologies are under development to reduce cold start hydrocarbon emissions, including close-coupled catalysts as disclosed in Ball, D. J., xe2x80x9cDistribution of warm-up and Underfloor Catalyst Volumes,xe2x80x9d SAE 922338, 1992; electrically heated catalysts as disclosed in Piotrowski, G. K., xe2x80x9cEvaluation of a Resistively Heated Metal Monolith Catalytic Converter on a Gasoline-Fueled Vehicle, EPA/AA/CTAAB/88-12,1988 and Hurley, R. G., xe2x80x9cEvaluation of Metallic and Electrically Heated Metallic Catalysts on a Gasoline Fueled Vehicle,xe2x80x9d SAE 900504, 1990; hydrocarbon absorbers as disclosed in Heimrich, M. J., Smith, L. R., and Kitowski, J., xe2x80x9cCold Start Hydrocarbon Collection for Advanced Exhaust Emission Control,xe2x80x9d SAE 920847, 1992 and Hochmuth, J. K., Burk, P. L., Telentino, C., and Mignano, M. J., xe2x80x9cHydrocarbon Traps for Controlling Cold Start Emissions,xe2x80x9d SAE 930739, 1993; bypass catalysts as disclosed in Fraidl, G. K., Quissrk, F. and Winklhofer, E., xe2x80x9cImprovement of LEV/ULEV Potential of Fuel Efficient High Performance Engines,xe2x80x9d SAE 920416, 1992; and burners as disclosed in Ma, T., Collings, N. and Hands, T., xe2x80x9cExhaust Gas Ignition (EGI)xe2x80x94A New Concept for Rapid Light-off of Automotive Exhaust Catalyst,xe2x80x9d SAE 920400, 1992. It has been reported that close-coupled catalysts, especially Pd-containing catalysts, are very effective at reducing hydrocarbon emissions during a cold start of the FTP cycle as disclosed in Ball, D. J., xe2x80x9cDistribution of warm-up and Underfloor Catalyst Volumes,xe2x80x9d SAE 922338, 1992; Summers, J. C., Skowron, J. F., and Miller, M. J., xe2x80x9cUse of Light-Off Catalysts to Meet the California LEV/ULEV Standards,xe2x80x9d SAE 930386, 1993; and Ball, D. J., xe2x80x9cA Warm-up and Underfloor Converter Parametric Study,xe2x80x9d SAE 932765, 1993. Recently, Ford has reported a successful application of Pd-only catalyst for meeting stringent emission standards as disclosed in Dettling, J., Hu, Z, Lui, Y., Smaling, R., Wan, C and Punke, A., xe2x80x9cSMART Pd TWC Technology to Meet Stringent Standards,xe2x80x9d Presented at CAPoC3 Third International Congress on Catalyst and Automobile Pollution Control, Apr. 20-22, 1994, Brussels.
A typical motor vehicle catalyst is an underfloor TWC catalyst which catalyzes the oxidation by oxygen in the exhaust gas of the unburned hydrocarbons and carbon monoxide and the reduction of nitrogen oxides to nitrogen. TWC catalysts which exhibit good activity and long life comprise one or more precious metal components, e.g., platinum group metal components such as platinum, palladium, rhodium, ruthenium and iridium located upon a high surface area, refractory oxide support, e.g., a high surface area alumina coating. The support is carried on a suitable carrier or substrate such as a monolithic carrier comprising a refractory ceramic or metal honeycomb structure, or refractory particles such as spheres or short, extruded segments of a suitable refractory material.
U.S. Pat. No. 4,134,860 relates to the manufacture of catalyst structures. The catalyst composition can contain platinum group metals, base metals, rare earth metals and refractory, such as alumina support. The composition can be deposited on a relatively inert carrier such as a honeycomb.
The high surface area alumina support materials, also referred to as xe2x80x9cgamma aluminaxe2x80x9d or xe2x80x9cactivated alumina,xe2x80x9d typically exhibit a BET surface area in excess of 60 square meters per gram (xe2x80x9cm2/gxe2x80x9d), often up to about 200 m2/g or more. Such activated alumina is usually a mixture of the gamma and delta phases of alumina, but may also contain substantial amounts of eta, kappa and theta alumina phases. It is disclosed to utilize refractory metal oxides other than activated alumina as a support for at least some of the catalytic components in a given catalyst. For example, bulk ceria, zirconia, alpha alumina and other materials are known for such use. Although many of these materials suffer from the disadvantage of having a considerably lower BET surface area than activated alumina, that disadvantage tends to be offset by a greater durability of the resulting catalyst.
In a moving vehicle, exhaust gas temperatures can reach 1000xc2x0 C., and such elevated temperatures cause the activated alumina (or other) support material to undergo thermal degradation caused by a phase transition with accompanying volume shrinkage, especially in the presence of steam, whereby the catalytic metal becomes occluded in the shrunken support medium with a loss of exposed catalyst surface area and a corresponding decrease in catalytic activity. It is a known expedient in the art to stabilize alumina supports against such thermal degradation by the use of materials such as zirconia, titania, alkaline earth metal oxides such as baria, calcia or strontia or rare earth metal oxides, such as ceria, lanthana and mixtures of two or more rare earth metal oxides. For example, see C. D. Keith et al., U.S. Pat. No. 4,171,288.
Bulk cerium oxide (ceria) is disclosed to provide an excellent refractory oxide support for platinum group metals other than rhodium, and enables the attainment of highly dispersed, small crystallites of platinum on the ceria particles, and that the bulk ceria may be stabilized by impregnation with a solution of an aluminum compound, followed by calcination. U.S. Pat. No. 4,714,694 of C. Z. Wan et al., discloses aluminum-stabilized bulk ceria, optionally combined with an activated alumina, to serve as a refractory oxide support for platinum group metal components impregnated thereon. The use of bulk ceria as a catalyst support for platinum group metal catalysts other than rhodium, is also disclosed in U.S. Pat. No. 4,727,052 of C. Z. Wan et al., and in U.S. Pat. No. 4,708,946 of Ohata et al.
U.S. Pat. No. 4,923,842 discloses a catalytic composition for treating exhaust gases comprising a first support having dispersed thereon at least one oxygen storage component and at least one noble metal component, and having dispersed immediately thereon an overlayer comprising lanthanum oxide and optionally a second support. The catalyst layer is separate from the lanthanum oxide. The noble metal can include platinum, palladium, rhodium, ruthenium and iridium. The oxygen storage component can include the oxide of a metal from the group consisting of iron, nickel, cobalt and the rare earths. Illustrative of these are cerium, lanthanum, neodymium, praseodymium, etc. Oxides of cerium and praseodymium are particularly useful as oxygen storage components.
U.S. Pat. No. 4,808,564 discloses a catalyst for the purification of exhaust gases having improved durability which comprises a support substrate, a catalyst carrier layer formed on the support substrate and catalyst ingredients carried on the catalyst carrier layer. The catalyst carrier layer comprises oxides of lanthanum and cerium in which the molar fraction of lanthanum atoms to total rare earth atoms is 0.05 to 0.20 and the ratio of the number of the total rare earth atoms to the number of aluminum atoms is 0.05 to 0.25.
U.S. Pat. No. 4,438,219 discloses an alumina-supported catalyst for use on a substrate. The catalyst is stable at high temperatures. The stabilizing material is disclosed to be one of several compounds including those derived from barium, silicon, rare earth metals, alkali and alkaline earth metals, boron, thorium, hafnium and zirconium. Of the stabilizing materials barium oxide, silicon dioxide and rare earth oxides which include lanthanum, cerium, praseodymium, neodymium, and others are indicated to be preferred. It is disclosed that contacting them with some calcined alumina film permits the calcined alumina film to retain a high surface area at higher temperatures.
U.S. Pat. Nos. 4,476,246, 4,591,578 and 4,591,580 disclose three-way catalyst compositions comprising alumina, ceria, an alkali metal oxide promoter and noble metals. U.S. Pat. No. 4,591,518 discloses a catalyst comprising an alumina support with components deposited thereon consisting essentially of a lanthana component, ceria, an alkali metal oxide and a platinum group metal. U.S. Pat. No. 4,591,580 discloses an alumina-supported platinum group metal catalyst. The support is sequentially modified to include support stabilization by lanthana or lanthana rich rare earth oxides, double promotion by ceria and alkali metal oxides and optionally nickel oxide.
Palladium-containing catalyst compositions, see, e.g., U.S. Pat. No. 4,624,940, have been found useful for high temperature applications. The combination of lanthanum and barium is found to provide a superior hydrothermal stabilization of alumina which supports the catalytic component, palladium.
U.S. Pat. No. 4,780,447 discloses a catalyst which is capable of controlling CH, CO and NOx as well as H2S in emissions from the tailpipe of catalytic coinverter-equipped automobiles The use of the oxides of nickel and/or iron is disclosed as a hydrogen sulfide gettering-type of compound.
U.S. Pat. No. 4,965,243 discloses a method to improve thermal stability of a TWC catalyst containing precious metals by incorporating a barium compound and a zirconium compound, together with ceria and alumina. This is stated to form a catalytic moiety to enhance stability of the alumina washcoat upon exposure to high temperature.
J01210032 (and AU-615721) discloses a catalytic composition comprising palladium, rhodium, active alumina, a cerium compound, a strontium compound and a zirconium compound. These patents suggest the utility of alkaline earth metals in combination with ceria, zirconias to form a thermally-stable alumina-supported palladium-containing washcoat.
U.S. Pat. Nos. 4,624,940 and 5,057,483 refer to ceria-zirconia containing particles. It is found that ceria can be dispersed homogeneously throughout the zirconia matrix up to 30 weight percent of the total weight of the ceria-zirconia composite to form a solid solution. A co-formed (e.g., co-precipitated) ceria oxide-zirconia particulate composite can enhance the ceria utility in particles containing ceria-zirconia mixture. The ceria provides the zirconia stabilization and also acts as an oxygen storage component. The ""483 patent discloses that neodymium and/or yttrium can be added to the ceria-zirconia composite to modify the resultant oxide properties as desired.
U.S. Pat. No. 4,504,598 discloses a process for producing a high temperature resistant TWC catalyst. The process includes forming an aqueous slurry of particles of a gamma or activated alumina and impregnating the alumina with soluble salts of selected metals including cerium, zirconium, at least one of iron and nickel and at least one of platinum, palladium and rhodium and, optionally, at least one of neodymium, lanthanum, and praseodymium. The impregnated alumina is calcined at 600xc2x0 C. and then dispersed in water to prepare a slurry which is coated on a honeycomb carrier and dried to obtain a finished catalyst.
U.S. Pat. No. 4,587,231 discloses a method of producing a monolithic three-way catalyst for the purification of exhaust gases. First, a mixed oxide coating is provided to a monolithic carrier by treating the carrier with a coating slip in which an active alumina powder containing cerium oxide is dispersed together with a ceria powder and then baking the treated carrier. Next platinum, rhodium and/or palladium are deposited on the oxide coating by thermal decomposition. Optionally, a zirconia powder may be added to the coating slip.
It is a continuing goal to develop a TWC catalyst system which is inexpensive and stable and which permits the attainment of ULEV standards without the necessity for mechanical emission control devices such as air pumps and without adversely affecting the engine/exhaust architecture or performance.
The present invention relates to a composite of cerium, zirconium and samarium components and to a catalyst composition containing such composite as well as the use of such catalyst composition for the treatment of a gas stream to reduce contaminants contained therein. The catalyst composition which may be utilized in a close-coupled and/or medium-coupled mode adjacent to or near the exhaust manifold of the engine, and/or in a catalytic converter located xe2x80x9cunder the floorxe2x80x9d of the vehicle downstream of the exhaust manifold. The catalyst composition may be utilized in the form of a single or multiple bricks, a single or multiple canisters, etc.
The particular mode (i.e., placement in respect to the exhaust manifold of the engine) and usage of the catalyst composition in the form of single or multiple bricks or canisters will depend on various factors such as the level of pollutants in the exhaust gas stream at the outset, desired maximum level of pollutants at the cold start phase of engine operation, auxiliary mechanical emission control devices such as air pumps, engine/exhaust architecture, etc.
More particularly, the catalyst composition of the invention is designed to reduce pollutants in automotive engine exhaust gas streams at temperatures as low as 350xc2x0 C., preferably as low as 300xc2x0 C. and more preferably as low as 200xc2x0 C. The catalyst composition of the present comprises components which catalyze low temperature reactions. This is indicated by the light-off temperature. The light-off temperature for a specific component is the temperature at which 50% of that component reacts. It has been found that the catalyst compositions of the present invention provide for significant improvements in nitrogen oxides conversion as well as lower light-off temperatures in comparison to prior art TWC catalyst compositions. Moreover, the catalyst compositions of the invention are thermally stable upon exposure to temperatures up to 1100xc2x0 C. and higher d ring the operating life of the engine. At the same time, the catalyst composition of the invention provides a relatively high hydrocarbon conversion rate as well as a high rate of conversion of nitrogen oxides to nitrogen.
The composite of the present invention comprises a cerium component, a zirconium component and a samarium component. Preferably, the composite is in the form of a particulate oxide composite which comprises ceria, zirconia and samaria. The cerium component is present in the amount of 10 to about 90 wt. % preferably 15 to 70 wt. %, the zirconium component is present in the amount of about 10 to about 90 wt. %, preferably 15 to 70 wt. %, and the samarium component is present in the amount of about 1 to about 40 wt. %, preferably 7 to 20 wt. %, based on the weight of the composite. The catalyst composition of the present invention comprises a mixture of (a) the foregoing composite, (b) a catalytically effective amount of at least one precious metal component and (c) a refractory metal oxide support. The catalyst composition is preferably disposed on a carrier, typically a metal or honeycomb, in a desired amount. For example, the catalyst composition plus the support may comprise about 2 to about 50 wt. %, preferably 5 to 20 wt. %, based on the weight of the finished carrier, i.e., the weight of the catalyst composition plus the weight of the support plus the weight of the carrier. Typically, the composite will be present in the amount of about 0.01 to about 3 g/in3, preferably 0.1 to 1 g/in3, of the carrier.
Preferably, the precious metal component is formed as a layer or coating upon the support and the resultant coated support is then mixed with the composite. The mixture of the precious metal-coated support and the composite is then deposited upon the carrier generally K a coated layer over most, if not all, of the surfaces of the carrier contacted. The combined structure, i.e., the mixture of the precious metal-coated support and the composite plus carrier, is then dried at a temperature of about 110xc2x0 C. for 2 to 5 hours and calcined in air at a temperature of 400 to 600xc2x0 C.
In general, any suitable carrier may be used for the catalyst composition such as a monolithic carrier having a honeycomb structure, i.e., a plurality of gas flow passages extending therethrough from an inlet or an outlet face of the carrier, so that the passages are open to fluid flow therethrough. The passages are defined by walls on which the catalytic material is coated as a xe2x80x9cwashcoatxe2x80x9d so that the gases flowing through the passages will contact the catalytic material. The flow passages of the monolithic carrier are thin-walled channels which can be of any suitable cross-sectional shape and size such as trapezoidal, rectangular, square, sinusoidal, hexagonal, oval, circular, etc. Such structures may contain from about 60 to about 700 or more, usually about 200 to 400, gas inlet openings (xe2x80x9ccellsxe2x80x9d) per square inch of cross section.
For the purposes of the present invention, when the catalyst composition of the invention is coated onto such a carrier typically as a washcoat, the amounts of the various components are presented based on grams per volume. When the ingredients are applied as a thin coating to a carrier substrate, the amounts of ingredients are conventionally expressed as grams per cubic foot (g/ft3) of the carrier for the precious metal component(s) and grams per cubic inch (g/in3) of the carrier for the other ingredients (i.e., the composite and the support) as this measure accommodates different gas flow passage cell sizes in different monolithic carrier substrates.
The carrier may comprise a refractory ceramic or metal having a honeycomb structure. Suitable refractory ceramic materials include alumina, silica, titania and zirconia compounds, e.g., cordierite (which is preferred), cordierite-alpha alumina, silicon nitride, zircon mullite, spodumene, alumina-silica magnesia, zircon silicate, sillimanite, magnesium silicates, zircon petalite, alpha alumina and aluminosilicates. A metallic honeycomb made be made of a refractory metal such as stainless steel or other suitable iron-based corrosion-resistant alloys.
The refractory metal oxide support includes materials such as activated compounds selected from the group consisting of alumina (which is preferred), silica, titania, silica-alumina, alumina-silicates, alumina-zirconia, alumina-chromia, alumina-ceria and mixtures thereof Typically, the refractory metal oxide support will be present in the amount of about 0.1 to about 4.0 g/in3 of carrier and will be present in the form of finely divided, high surface area particles having a particle size above 10-15 micrometers. Preferably, the activated alumina is thermally stabilized to retard undesirable alumina phase transformations from gamma to alpha at elevated temperatures by doping the activated alumina with a rare earth component such as lanthanum (preferred) or neodymium or mixtures thereof in an amount of about 0.02 to about 0.5 g/in3 of carrier.
The precious metal component of the catalyst composition comprises one or more metals selected from the group consisting of gold, silver and platinum group metals. Platinum group metals include platinum, palladium, rhodium, ruthenium and iridium components and mixtures thereof The precious metal component(s) are typically present in the amount of about 0.1 to about 250 g/ft3, preferably 0.5 to 100 g/ft3 of the carrier. The preferred precious metal components are platinum, rhodium or a mixture of platinum and rhodium metal components which are typically present in a platinum:rhodium ratio of about 0.1:1 to about 20:1, preferably 1:1 to 10:1.
A process which can be used to prepare the composite of the present invention starts with the preparation of a zirconium hydroxide sol. This sol can be prepared by precipitating zirconium sulfate with sodium hydroxide at high temperature reflux, typically from 90 to 100xc2x0 C. to make nanometer-size crystals (typically up to 100 nanometers). Impurities, e.g., sodium, sulfur, etc. can be washed out with an aqueous liquid. An acid, e.g., nitric acid, can be used to break up the aggregates to obtain the zirconium hydroxide sol and to reduce the pH of the liquid. At this stage, the cerium and samarium components in the form of salts such as nitrates are added. The composite sol should be sufficiently acidic, e.g., a pH of 0.5 to 3, preferably, 0.5 to 2.0, at this point in order to keep the salts in solution. The pH can then be quickly increased, e.g., with ammonia, to precipitate the composite compounds. The formation of large aggregates is preferably avoided by controlling the pH. The precipitated composite can then be washed with an aqueous liquid such as deionized water and dried at suitable conditions in air in an oven at temperatures of up to 250xc2x0 C., typically at 150xc2x0 C., for as long as necessary, usually overnight. The precipitated composite can then be calcined in air at elevated temperatures to convert the composite to particulate oxide composite which comprises ceria, zirconia and samaria. The calcination process is typically carried out at a temperature of 450 to 750xc2x0 C., preferably 550xc2x0 C. for 0.5 to 10 hours, preferably 2 hours. The resultant composite of ceria, zirconia and samaria may then be mixed with the precious metal component which has been preferably disposed, i.e., layered or coated, on the refractory metal oxide support.
The catalyst composition may be prepared by mixing the composite prepared as set forth above with the precious metal component and the refractory metal oxide support in the form of an aqueous slurry, comminuting the slurry (i.e., by ball milling), mixing the comminuted slurry with the carrier followed by drying and calcination. However, it is preferred that the composite be mixed with the precious metal component which has been previously disposed on the refractory metal oxide support.
The precious metal component(s) disposed on the refractory metal oxide support may be prepared in the following manner which involves the preparation of an aqueous slurry of the precious metal component(s) and the refractory metal oxide support. The method involves fixing the precious metal component(s) onto at least one support. The fixing step can be any of the suitable fixing steps known in the prior art such as chemical or thermal fixing. A preferred fixing step is to thermally fix the precious metal component(s) to the support. This is preferably conducted in air at a temperature of 50 to 500xc2x0 C. for about 0.5 to about 2 hours.
Typically, the refractive metal oxide support, e.g., activated alumina, is impregnated with an aqueous solution or dispersion of the precious metal component present as a compound or complex. The selected precious metal compound or complex should be one which, upon calcination or use thereof, decomposes or otherwise converts to a catalytically active form, usually the metal or metal oxide. Water-soluble compounds or water-dispersible compounds or complexes of the metal component may be used as long as the liquid medium used to impregnate or deposit the metal component onto the refractory metal oxide support particles does not adversely react with the metal or its compound or its complex or other components which may be present in the catalyst composition and is capable of being removed from the metal component by volatilization or decomposition upon heating and/or application of a vacuum. In some cases, the completion of removal of the liquid may not take place until the catalyst is placed into use and subjected to the high temperatures encountered during operation. Generally, both from the point of view of economics and environmental aspects, aqueous solutions of soluble compounds or complexes of the platinum-group metals are preferred. For example, suitable compounds are chloroplatinic acid, amine-solubilized platinum hydroxide, palladium nitrate or palladium chloride, rhodium chloride, rhodium nitrate, hexamine rhodium chloride, etc. During the calcination step, or at least during the initial phase of use of the catalyst, such compounds are converted into a catalytically active form of the platinum-group metal or a compound thereof
A preferred method of preparing the catalyst composition of the invention is to prepare a mixture of a solution of at least one platinum-group metal, e.g., platinum amine complex and/or rhodium nitrate, and at least one finely divided, high surface area, refractory metal oxide support, e.g., activated alumina, which is sufficiently dry to absorb substantially all of the solution to form a slurry. Preferably, the slurry is acidic, having a pH of about 2 to less than 7. The pH of the slurry may be lowered by the addition of a minor amount of an inorganic or organic acid such as acetic acid (preferred), hydrochloric acid or nitric acid, to the slurry. Thereafter, if desired, a refractory metal oxide support stabilizer, e.g., lanthanum nitrate, and/or a binder, e.g., zirconia acetate, and/or an alkaline earth metal compound promoter, e.g., strontium nitrate, may be added to the slurry. Thereafter, the ceria-zirconia-samaria composite prepared as described above is added. At this point, the slurry of the catalyst composition of the invention will have a solids concentration of about 45-50 wt. %, a pH of 4-5 and a viscosity of 50-100 centipoise at 20xc2x0 C.
The slurry of the catalyst composition is thereafter comminuted. The comminution may be accomplished in a ball mill or other similar equipment for 4-8 hours with the result such that the final particle size will typically be that the final particle size will be 90% less than about 10 microns. This slurry can then be used to coat a macro size carrier preferably having a low surface area. For example, a honeycomb carrier such as cordierite is immersed in the slurry and the coated honeycomb carrier is then placed in a drying oven and dried at about 110xc2x0 C. for about two to five hours. The dried honeycomb is then calcined in air at about 400-600xc2x0 C. for about one hour.
The present invention is illustrated by the following examples which are not intended to limit the scope of the invention. Unless otherwise indicated, all amounts and percentages are on a weight basis.

Catalyst composition for purifying exhaust gas


In a mobile communication system having mobile foreign agents, the present invention eliminates the use of multiple source/destination headers attached to an information packet during the tunneling operation by using either a decapsulation/encapsulation or a forwarding operation with the encapsulated information packet. Either of these operations reduces the overhead incurred in the multiple encapsulation headers by reducing encapsulation of the information packet to a single level.

This invention relates to an improved Internet Protocol (IP) based mobile communications system having static agents (such as a Home Agent and a Foreign Agent) and mobility agents (such as Mobile Foreign Agents and Mobile Nodes), as well as an improved method for operating said system.
Present-day Internet communications represent the synthesis of technical developments begun in the 1960sxe2x80x94the development of a system to support communications between different United States military computer networks, and the subsequent development of a system to support the communication between research computer networks at United States universities. These technological developments would subsequently revolutionize the world of computing.
The Internet, like so many other high tech developments, grew from research originally performed by the United States Department of Defense. In the 1960s, Defense Department officials began to notice that the military was accumulating a large collection of computersxe2x80x94some of which were connected to large open computer networks and others that were connected to smaller closed computer networks. A network is a collection of computers or computer-like devices communicating across a common transmission medium. Computers on the Defense Department""s open computer networks, however, could not communicate with the other military computers on the closed systems.
Defense Department officials requested that a system be built to permit communication between these different computer networks. The Defense Department recognized, however, that a single centralized system would be vulnerable to missile attacks or sabotage. Accordingly, the Defense Department mandated that the system to be used for communication between these military computer networks be decentralized and that no critical services be concentrated in a few, vulnerable failure points. In order to achieve these goals, the Defense Department established a decentralized standard protocol for communication between network computers.
A few years later, the National Science Foundation (NSF) wanted to connect network computers at various research institutions across the country. The NSF adopted the Defense Department""s protocol for communication, and this combination of research computer networks would eventually evolve into the Internet.
Internet Protocols
The Defense Department""s communication protocol governing data transmission between computers on different networks was called the Internet Protocol (IP) standard. The IP standard now supports communications between computers and networks on the Internet. The IP standard identifies the types of services to be provided to users, and specifies the mechanisms needed to support these services. The IP standard also describes the upper and lower system interfaces, defines the services to be provided on these interfaces, and outlines the execution environment for services needed in the system.
A transmission protocol, called the Transmission Control Protocol (TCP), was also developed to provide connection-oriented, end-to-end data transmission between packet-switched computer networks. The combination of TCP with IP (TCP/IP) forms a system or suite of protocols for data transfer and communication between computers on the Internet. The TCP/IP standard has become mandatory for use in all packet switching networks that connect or have the potential for utilizing connectivity across network or sub-network boundaries.
The TCP/IP Protocol
In a typical Internet-based communication scenario, data is transmitted from an applications program in a first computer, through the first computer""s network hardware, and across the transmission medium to the intended destination on the Internet. After receipt at a destination computer network, the data is transmitted through the destination network to a second computer. The second computer then interprets the communication using the identical protocols on a similar application program. Because of the standard protocols used in Internet communications, the TCP/IP protocol on the second computer should decode the transmitted information into the original data transmitted by the first computer.
The TCP/IP Protocol Layers
One of the rules in TCP/IP communications is that a computer user does not need to get involved with details of data communication. In order to accomplish this goal, the TCP/IP standard imposes a layered communications system structure. All the layers are located on each computer in the network, and each module or layer is a separate component that theoretically functions independent of the other layers.
TCP/IP and its related protocols form a standardized system for defining how data should be processed, transmitted and received on the Internet. TCP/IP defines the network communication process, and more importantly, defines how a unit of data should look and what information the message should contain so that the receiving computer can interpret the message correctly. Because the standardized layer design of TCP/IP, a consistent conversion of base data is ensured regardless of the version or vendor of the TCP/IP conversion software.
When a first computer transmits a data message to a second computer on the Internetxe2x80x94either sending a message or requesting informationxe2x80x94the TCP/IP Protocol Layers in the first computer prepare the base data for transmission to a second computer by adding additional information to the base data. New pieces of information are added to the base data as the base data descends through each layer in the protocol. After processing, the base data with various headers will form a fully structured information packet under the TCP/IP protocol. The information packet will include header information that identifies the source of the information packet and its intended destination.
After the base data has been processed by all the layers in the protocol, it is ready for transmission across the Internet to the destination computer. After receipt of the information packet, the second computer operates on the information packet using the same set of TCP/IP protocol layersxe2x80x94only in reverse order. As the transmitted information packet ascends through the protocol layers in the second computer, each protocol level strips away the information added by the first computer to ultimately leave the base data in the applications program of the second computer.
TCP/IP Addressing and Routing
A computer operating on a network is assigned a unique physical address. On a Local Area Network (xe2x80x9cLANxe2x80x9d), the physical address of the computer is a number given to computer""s network adapter card. Hardware LAN protocols use this physical address to deliver packets of data to computers on the LAN.
On the Internet, the TCP/IP protocol routes data packets using logical addressing. The network software in the Network Layer generates logical addresses. Specifically, a logical address in the TCP/IP network is translated into a corresponding physical address using the ARP (Address Resolution Protocol) and RARP (Reverse Address Resolution Protocol) protocols in the Network Layer.
The TCP/IP""s logical address is also called an IP address. The IP address can include: (1) a network ID number identifying a network, (2) a sub-network ID number identifying a sub-network on the network, and, (3) a host ID number identifying a particular computer on the sub-network. The header data in the information packet will include source and destination addresses. The IP addressing scheme imposes a sensible addressing scheme that reflects the internal organization of the network or sub-network.
A computer network is often subdivided into smaller sub-networks. The computer network is divided in this manner to increase data transmission efficiency and reduce overall network traffic. Routers are used to regulate the flow of data into and out of designated sub-networks of the computer network.
A router interprets the logical address information of a data packet, such as an IP address, and directs the data packet across the network to its intended destination. Data addressed between computers on the sub-network does not pass through the router to the greater network, and therefore does not clutter the transmission lines of the greater network. If data is addressed to a computer outside the sub-network, however, the router forwards the data onto the larger network.
The TCP/IP network includes protocols that define how routers will determine the path for data through the network. Routing decisions are based upon information in the IP packet header and entries in each router""s routing table. A routing table possesses sufficient information for a router to make a determination on whether to accept the communicated information on behalf of a destination computer, or pass the information onto another router in the network. The routing table also permits the router to determine where the information should be forwarded within the network or sub-network.
The routing table can be configured manually with routing table entries or a dynamic routing protocol that can accommodate changing network topologiesxe2x80x94network architecture or network layouts, routers, and interconnections between hosts and routers. In a dynamic routing protocol, a router advertises reachability when it sends updated routing information to a second router claiming that the first router is capable of reaching one or more destination addresses. Advertising accessibility is important to the process of receiving, directing and re-directing data packets on the Internet.
Internet protocols were originally developed with an assumption that Internet users, which are assigned a unique IP address, would be connected to a single, fixed networkxe2x80x94that is, one physical fixed location. With the advent of portable and handheld computers, however, the movement of Internet users within a network and across network boundaries has become quite common. Because of this highly mobile Internet usage, the implicit design assumptions for the Internet protocols have been violated.
The present invention relates to an improved IP-based mobile system defined by an apparatus and method for managing bi-directional transmission of information with at least one Mobile Node in a wireless communication system. The term xe2x80x9cMobile Nodexe2x80x9d includes a mobile communication unit, and, in addition to the Mobile Node, the communication system has a home network, a foreign network, and at least one mobile foreign network. The Mobile Node may change its point of attachment to the Internet through these other networks, but the Mobile Node will always be associated with a single Mobile Node home network for IP addressing purposes. For the purposes of this application, a network includes a separate computer network or sub-network on a wireless communication system.
The Mobile Node home network has a Home Agent and the foreign network has a Foreign Agentxe2x80x94both of which control the routing of packeted information into and out of their network. The mobile foreign network also has a Mobile Foreign Agent to assist with routing of packeted information into and out of the mobile network. Like the Mobile Node, the Mobile Foreign Agent may change its point of attachment to the Internet through other networks, but the Mobile Foreign Agent will always be associated with a single Mobile Foreign Agent home network for IP addressing purposes.
The terms Home Agent, Foreign Agent, and Mobile Foreign Agent may be defined in the Mobile IP Protocol (RFC 2002), but these agents are not restricted to a single protocol or system. In fact, the term Home Agent, as used in this application, can refer to a Home Mobility Manager, Home Location Register, Home Serving Entity, or any other agent at a home network having the responsibility to manage mobility-related functionality for a Mobile Node on a home network. Likewise, the term Foreign Agent, as used in this application, can refer to a Serving Mobility Manager, Visited Location Register, Visiting Serving Entity, or any other agent on a foreign network having the responsibility to manage mobility-related functionality for a Mobile Node on a foreign network.
Care-Of Addressing For Mobile Nodes
An IP-based mobile system controls mobile communication by managing the xe2x80x9ccare-ofxe2x80x9d address assignments. A Mobile Node Home Agent comprises a router with an interface on the Mobile Node""s home network. When the Mobile Node is located on the home network, packeted information may be directed to the Mobile Node by the Mobile Node Home Agent through a direct communication link.
When the Mobile Node moves to a foreign network or mobile foreign network, the Mobile Node keeps the Mobile Node Home Agent informed of its current location by registering a care-of address with the Mobile Node Home Agent. This care-of address represents the current foreign network or mobile foreign network where the Mobile Node is located. For a Mobile Node, the care-of address is used to re-route all packeted information destined for a Mobile Node to the foreign network or mobile foreign networks associated with the Mobile Node.
Care-Of Addressing For Mobile Foreign Networks
Each Mobile Foreign Agent has a MFA Home Agent on an MFA home network. When the Mobile Foreign Agent is attached to the MFA home network, all packeted information directed to nodes attached to the Mobile Foreign Agent will be sent to the MFA home network for routing directly to the Mobile Foreign Agent.
Like the Mobile Node, however, each Mobile Foreign Agent can move from one network attachment to another. When not located at the MFA home network, the Mobile Foreign Agent will have a care-of address identifying the foreign network or other mobile foreign network where the Mobile Foreign Agent is located. The Mobile Foreign Agent will register this care-of address with it MFA home network to keep the home network aware of its current location. The care-of address is used to re-route all packeted information destined for the Mobile Foreign Agent to the appropriate foreign network or other mobile foreign network associated with the addressed Mobile Foreign Agent.
When a Correspondent Node communicates to a Mobile Node associated with a Mobile Foreign Agent and the Mobile Foreign Agent is located outside the MFA home network, the information packet from the Correspondent Node will initially be sent to the Home Agent (due to the IP routing mechanism) of the Mobile Node. This Mobile Node Home Agent will re-route (or xe2x80x9ctunnelxe2x80x9d) the information packet to the care-of address of the Mobile Foreign Agent. Through normal IP routing, the information packet will eventually end up at the MFA Home Agent. The MFA Home Agent then uses the care-of address to direct (or xe2x80x9ctunnelxe2x80x9d) information packets to the Mobile Foreign Agent. The Mobile Foreign Agent then de-tunnels the packet and forwards it to the Mobile Node. While the present invention can operate under the Mobile IP protocol (RFC 2002), the invention is not limited to this protocol and can be used with any IP-based mobile system having mobility agents.
Tunneling and Encapsulation
If the Mobile Node is coupled to a foreign network, the Home Agent will xe2x80x9ctunnelxe2x80x9d communications to the Mobile Node. When xe2x80x9ctunnelingxe2x80x9d a communication, the Home Agent receives an information packet addressed to the Mobile Node, and the Home Agent will tunnel, or transfer, these data packets to the Mobile Node""s current location on its then associated foreign network or mobile foreign network. Under standard protocols, the Home Agent will encapsulate the data packet with at least source/destination information in an additional header to assist in the tunneling process.
If the Mobile Node is attached to a Mobile Foreign Agent, the tunneling operation will require that the information packet be sent from the Mobile Node""s Home Agent to the home network of the Mobile Foreign Agent (MFA home network). The MFA Home Agent on the MFA home network then receives the information packet (since the IP address of the Mobile Foreign Agent is topologically the same as the IP addresses of the MFA home network).
After receipt of the information packet, the MFA Home Agent will encapsulate the packeted information with an additional source/destination header before forwarding the packeted information onto the appropriate foreign network or MFA foreign network. The encapsulation of the information packet with source/destination headers must occur for every Mobile Foreign Agent present between the Mobile Node and the foreign network.
The additional header information could become quite extended as more Mobile Foreign Agents are present between the foreign network and the Mobile Node. In fact, after the addition of only a few additional Mobile Foreign Agents, the header information could become greater than the base data size (payload) in the information packet.
It is therefore an objective of the present invention to reduce the size of headers attached to information packets during multiple header encapsulations. This objective will reduce the overall size of the headers transmitted in an information packet thereby reducing the amount of overhead control information. As a result, this invention will increase the net amount of data transmitted with the information packet. This objective is accomplished by two novel methodsxe2x80x94called decapsulation/encapsulation and forwarding. While either novel technique may be used to accomplish the goals of this invention, each technique will eliminate the multiple levels of encapsulation by supporting the tunneling of information packets in the mobile network using a single level of encapsulation.
Under existing protocols (such as RFC 2002), the Foreign Agent in the foreign network will receive an encapsulated information packet for routing. The Foreign Agent processes the data packets by decapsulating the outer source/destination header in the information packet. The Foreign Agent will then transfer the information packet to the next Mobile Foreign Agent or the Mobile Node as identified in the decapsulated destination field of the information packet. Successive decapsulation operations will continue until all the multiple levels of encapsulation are exhausted and the destination field in the information packet identifies the final destination of the Mobile Node. The existing protocols depend on the existence of multiple levels of encapsulation to direct the information packet through the foreign network and the mobile foreign networks.
Because the present invention eliminates multiple levels of encapsulation, novel approaches are used to direct the information packets through the foreign network and mobile foreign networks. Accordingly, the present invention also includes two novel approaches for directing information packets through the foreign and mobile foreign networks with a single level of encapsulation, and these methods are called source routing and next hop routing. As with the encapsulation methods in the present invention, the information packet may be directed through the foreign network and Mobile Foreign Agents using either approach depending on the system requirements.
In this aspect of the invention, the Foreign Agent will use the information found in the internal data structures supported by the source routing or next hop routing schemes to efficiently route information packets to destinations within the foreign network or mobile foreign networks. The Foreign Agent will inspect the data structures used to support source routing and next hop routing much like a routing table to determine if a Mobile Node is already present on another part of the foreign network and mobile foreign networks attached to the Foreign Agent. If the Mobile Node is present, the information packet will be appropriately routed to the Mobile Node without transmitting the information packet outside the networks controlled by the foreign networks. Because the data structures supporting source routing and next hop routing are already available to the Foreign Agent, no modifications to the current system need to be effected apart from the small program alternations needed to search those data structures prior to transmission of information packets out of the network, and routing the information packet appropriately based on the results of that comparison.

Reduced overhead tunneling techniques in a communications network having mobile foreign agents

Abstract: Upon receipt of the information packet at the foreign agent on the communications system, the information packet is directed to the mobile node using a routing chain table maintained by the foreign agent or a next hop routing table maintained by the foreign agent and each mobile foreign agent in the transmission path. Once implemented, these data structures can also assist with routing of information packets within the foreign subnetwork.


A flashlight having a mechanism for preventing electrical contact members thereof from rusting comprises a battery frame including a plurality of slanted flexible bifurcation members for receiving one or more batteries, each bifurcation member having a recess proximate the electrode. In an unused position, batteries are disengaged from each other and from a bulb and a conductor coupled to bulb. While in use, by pushing a switch to hold bifurcation members upright in a secured position so.that batteries, bulb, and conductor are electrically coupled together with electrodes and a protuberance of conductor inserted through recesses, thereby forming a circuit from bulb to conductor via batteries.

The present invention relates to flashlights and more particularly to such a flashlight having mechanism for preventing electrical contact member thereof from rusting.
Conventionally, flashlight is operated by one or more batteries. Also, batteries are typically installed in flashlight in an unused state. Hence, in a special condition such as power out people may use flashlight immediately. It is known that circuit may not form in a single uninstalled battery. However, circuits may still form between battery and coupled bulb and between battery and coupled conductor of flashlight (e.g., negative electrode) even flashlight is not used. As a result, the contact points (e.g., above positions between battery and bulb and between battery and conductor of flashlight) tend to get rust after a relative long period of time. This can shorten a useful life of flashlight. A proposal is to clean such rest regularly. However, it is inconvenient. To the worse, electrical contact members of flashlight may be damaged during the cleaning if enough care is not taken.
Thus, it is desirable to provide an improved flashlight having mechanism for preventing electrical contact members thereof from rusting in order to overcome the above drawbacks of prior art.
It is an object of the present invention to provide a flashlight having a mechanism for preventing electrical contact members thereof from rusting comprising a light mechanism including a bulb, a reflector for securing the bulb, an internal threaded section, an elastic member, a flexible substantially L-shaped conductor coupled to the bulb and having protuberance on a vertical section, a battery frame including a horizontal section and a plurality of slanted flexible bifurcation members equally spaced on the horizontal section, each bifurcation member having a recess, and one or more batteries each secured between two of the adjacent bifurcation members with electrodes thereof proximate the recesses; a cylindrical container shaped handle for receiving the conductor, the batteries, and the battery frame and including a collar, a raised switch including a channel, two opposed lugs on one end of the channel, a bent trigger member having a projection on a slanted section and a push button on an open end of the slanted section, and a pin through lugs for pivotably securing the trigger member on the channel; and a cylindrical sleeve mechanism put on the handle and including a front outer threaded section matingly secured to the threaded section of the light mechanism together with the collar and the reflector to enclose the elastic member, and an opening on a surface. In an unused position, the batteries are disengaged from each other, a positive electrode of one of the batteries is disengaged from the bulb, and a negative electrode of the other battery is disengaged from the protuberance. While in a used position, the elastic member is compressed by pushing the push button forward for holding the bifurcation members upright and clinging the projection into the opening so that the batteries are electrically coupled together, the positive electrode of one of the batteries is coupled to the bulb, and the negative electrode of the other battery is coupled to the protuberance by inserting the positive electrodes of the batteries and the protuberance through the recesses, thereby forming a circuit from the bulb to the protuberance via the batteries.

Flashlight having mechanism for preventing electrical contact members thereof from rusting