Showing papers on "Potassium nitrate published in 1997"

Chemical synthesis of nitric oxide in the stomach from dietary nitrate in humans.

Abstract: BACKGROUND/AIMS: It has been suggested that dietary nitrate, after concentration in the saliva and reduction to nitrite by tongue surface bacteria, is chemically reduced to nitric oxide (NO) in the acidic conditions of the stomach. This study aimed to quantify this in humans. METHODS: Ten healthy fasting volunteers were studied twice, after oral administration of 2 mmol of potassium nitrate or potassium chloride. Plasma, salivary and gastric nitrate, salivary and gastric nitrite, and gastric headspace NO concentrations were measured over six hours. RESULTS: On the control day the parameters measured varied little from basal values. Gastric nitrate concentration was 105.3 (13) mumol/l (mean (SEM), plasma nitrate concentration was 17.9 (2.4) mumol/l, salivary nitrate concentration 92.6 (31.6) mumol/l, and nitrite concentration 53.9 (22.8) mumol/l. Gastric nitrite concentrations were minimal (< 1 mumol/l). Gastric headspace gas NO concentration was 16.4 (5.8) parts per million (ppm). After nitrate ingestion, gastric nitrate peaked at 20 minutes at 3430 (832) mumol/l, plasma nitrate at 134 (7.2) mumol/l, salivary nitrate at 1516.7 (280.5) mumol/l, and salivary nitrite at 761.5 (187.7) mumol/l after 20-40 minutes. Gastric nitrite concentrations tended to be low, variable, and any rise was non-sustained. Gastric NO concentrations rose considerably from 14.8 (3.1) ppm to 89.4 (28.6) ppm (p < 0.0001) after 60 minutes. All parameters remained increased significantly for the duration of the study. CONCLUSIONS: A very large and sustained increase in chemically derived gastric NO concentrations after an oral nitrate load was shown, which may be important both in host defence against swallowed pathogens and in gastric physiology.

Determination of δ18O and δ15N in Nitrate

Abstract: The analyses of both O and N isotopic compositions of nitrate have many potential applications in studies of nitrate sources and reactions in hydrology, oceanography, and atmospheric chemistry, but simple and precise methods for these analyses have yet to be developed. Testing of a new method involving reaction of potassium nitrate with catalyzed graphite (C + Pd + Au) at 520 °C resulted in quantitative recovery of N and O from nitrate as free CO2, K2CO3, and N2. The δ18O values of nitrate reference materials were obtained by analyzing both the CO2 and K2CO3 from catalyzed graphite combustion. Provisional values of δ18OVSMOW for the internationally distributed KNO3 reference materials IAEA-N3 and USGS-32 were both equal to +22.7 ± 0.5‰. Because the fraction of free CO2 and the isotopic fractionation factor between CO2 and K2CO3 were constant in the combustion products, the δ18O value of KNO3 could be calculated from measurements of the δ18O of free CO2. Thus, δ18OKNO3 = aδ18Ofree CO2 − b, where a and b we...

Optimization of culture medium for growth of Haematococcus pluvialis

Abstract: A central composite rotatable design was used to examine the effects of five components of the medium on the growth of Haematococcus pluvialis in batch culture. The medium components considered were: sodium acetate,potassium nitrate, major elements, trace elements and vitamins. Within the range of the concentrations tested, a moderate concentration of the major elements significantly enhanced algal growth, both in terms of specific growth rate and cell dry weight, whereas the vitamins had no significant effect. Based on the response surface contour plots and the results of numerical analyses, the optimal nutrient concentrations for growth in terms of specific growth rate were 0.51 g L-1 sodium acetate, 0.25 g L-1 potassium nitrate, 0.63 mL L-1 of the major element stock solution and 0.2 mL L-1 of the trace element stock solution. The optimal nutrient concentrations for biomass production were 1.64 g L-1 sodium acetate, 0.37 g L-1potassium nitrate, 2.52 mL L-1 of the major element stock solution and 0.03 mL L-1 of the trace element stock solution.

Vapor phase oxidation of propylene to propylene oxide

Abstract: Propylene is converted to propylene oxide in a vapor phase oxidation process employing a silver catalyst supported on an alkaline earth metal carbonate and containing both a potassium salt such as potassium nitrate and a molybdenum promoter. The potassium salt and the molybdenum promoter may be simultaneously supplied by the use of a potassium salt of a molybdenum oxyanion. The efficiency of the process is greatly enhanced through the simultaneous inclusion of carbon dioxide and an organic halide in the feedstream. The feedstream need not contain a nitrogen oxide species such as NO to attain high propylene oxide selectivity.

Method and composition for stabilizing soil and process for making the same

Abstract: A water soluble chemical composition for use as a soil stabilizer, conditer and structuring agent includes a dispersing agent such as a polyanionic sulfonated urea-melamine formaldehyde condensate, an aggregating agent such as a non-ionic water soluble urea-formaldehyde condensate having relative weight average molecular weights between 400 to 10,000 and polydispersity between 2.5 to 10, and a basic salt like di-sodium tetra borate and/or a neutral salt like sodium chloride and a nitrogen potassium or phosphorous containing compound such as potassium nitrate, phosphoric acid, potassium dihydrogen orthophosphate and the like, wherein the ratio of urea-formaldehyde to sulfonated urea-melamine-formaldehyde is between 0.2:1 to 2.0:1 and the final solid contents of this composition is between 1-15%. These compositions are then sprayed on top of sand or soil with conventional equipment and will impart significant improvements in their mechanical properties and their erosion resistance to water and wind.

Propylene oxide process using mixed precious metal catalyst supported on alkaline earth metal carbonate

Abstract: Propylene is oxidized to propylene oxide in the vapor phase using oxygen and a supported catalyst comprising silver, gold, a potassium promoter such as potassium nitrate or potassium carbonate and a support comprised in whole or in substantial part of an alkaline earth metal carbonate.

Gas-generative composition consisting essentially of ammonium perchlorate plus a chlorine scavenger and an organic fuel

Abstract: This invention relates to gas-generative compositions consisting essentially of ammonium perchlorate with a chlorine scavenger, such as strontium nitrate, barium nitrate, potassium nitrate, or lithium carbonate, the combination being present in an amount of about 30 to about 95% by weight, up to about 5% by weight of a binder, up to about 5% by weight of a burning rate catalyst, together with an organic fuel, such as guanidine nitrate. The fuel is in an amount complementary to the combined weight of ammonium perchlorate, burning rate catalyst, chlorine scavenger, and binder, at an oxidation ratio of 0.90 to 0.98. The invention also includes the method of inflating an inflatable device by generating gas employing the noted composition and a gas generator in which the gas-generative composition is that of the present invention.

Process for production of chemically prestressed glass

Abstract: The process for producing a chemically prestressed glass of very high surface quality includes subjecting an Li 2 O-free starting glass from the SiO 2 -Al 2 O 3 -M 2 O-MO system which also contains TiO 2 , CeO 2 and F 2 to chemical ion exchange by immersing it in a potassium salt bath at a temperature between 350° C. and 550° C. and at a residence time of between 0.5 and 20 hours to form the chemically prestressed glass. In a preferred embodiment of the process, the potassium salt bath contains a potassium nitrate melt and the glass is polished after prestressing. The chemically prestressed glass is particularly useful for making hard disks.

First isocratic separation of fourteen lanthanides and yttrium by high-performance chelation ion chromatography

Abstract: The possibility was demonstrated of the isocratic separation of 14 lanthanides and yttrium using a chromatographic column packed with iminodiacetic acid bonded to silica and with diluted nitric acid solutions in the presence of potassium nitrate as the eluent. The influence of concentration of nitric acid, ionic strength of the eluent and temperature was investigated. It was shown that in the presence of 0.5–1.0 M potassium nitrate the retention of the lanthanides is defined by the stability of the corresponding surface complexes with iminodiacetic acid functional groups. However, the presence of residual ion-exchange activity is still responsible for the selectivity of the separation of yttrium and Eu–Gd and Dy–Ho pairs.

Effects of physico-chemical factors influencing tyramine production by Carnobacterium divergens.

Abstract: F. MASSON, A. LEBERT, R. TALON AND M.C. MONTEL. 1997.Tyramine production by a strain of Carnobacterium divergens was tested in relation to different conditions of pH, temperature, glucose, oxygen availability, potassium nitrate and sodium chloride content, using a combination of a Doehlert and Plackett-Burman experimental design. A second degree polynomial model was chosen to describe tyramine production which was quantified by high performance liquid chromatography. Maximal tyramine production occurred during the stationary phase in acidic conditions obtained by low initial pH (5) or addition of glucose (0·6%) to the medium. Production was slower at 5°C than at 23°C and 10% sodium chloride inhibited this production. However, the formation of tyramine was not affected by the presence of potassium nitrate or oxygen availability.

Granular coated particles containing urea and metal nitrate, and process for making the same

Abstract: Granular coated particles suitable for use alone or in combination with other fertilizer particles as an nitrogen-dispersing agricultural fertilizer, and a process for making the granular coated particles are disclosed. The granular coated particles include particles formed from at least one metal nitrate, and a first coating layer surrounding each of the metal nitrate particles. The first coating layer is formed from a mixture containing urea and at least one metal nitrate. The metal nitrate particles each is substantially free and discrete from other metal nitrate particles. The metal nitrate is preferably sodium nitrate or potassium nitrate.

Preparation of Phase Stabilized Ammonium Nitrate (PSAN) by a Salting Out Process

Abstract: We describe a method for preparation of PSAN, where the process involves precipitation of ammonium nitrate with potassium nitrate from the aqueous solutions of their salts by the addition of acetone. This kind of process is often referred to as salting out process (Murray and Larson, 1965).

A process for producing high-purity potassium salts

Abstract: The present invention relates to a new selective process for producing high-purity potassium nitrate or potassium phosphate. The process uses a liquid agricultural or fermentation by-product, such as molasses, vinasse or potato thick juice as its potassium source and comprises the following unit operations: clarification, ion exchange, neutralization, concentration and crystallization. Importantly, the present invention also concerns a process for producing an ingredient for animal feed, said ingredient having a reduced potassium content.

Stabilized ammonium nitrate

Abstract: The invention relates to stabilized ammonium nitrate which no longer exhibits a transition point at 32° C. Its subject-matter is a new process for stabilizing ammonium nitrate and the new stabilized ammonium nitrate thus obtained. The stabilized ammonium nitrate according to the invention includes between 1% and 7% by weight of potassium nitrate and between 0.1% and 1% by weight of an organic dye containing at least one arylsulphonate group chosen from the class consisting of benzenesulphonate groups and naphthalenesulphonate groups. The stabilization of ammonium nitrate is necessary particularly for its use in propellants.

UV-irradiated potassium peroxodiphosphate and nitrate as excitation sources for luminol chemiluminescence

Abstract: Luminol-specific extrinsic lyoluminescence of UV-irradiated potassium peroxodiphosphate and potassium nitrate has been studied. UV irradiation of solid peroxodiphosphate can induce rupture of the peroxide bond and produce a stable solid solution of phosphate radicals in potassium peroxodiphosphate. The dissolution of the irradiated salt can liberate phosphate radicals which initiate a luminol chemiluminescence-generating pathway in alkaline solution. UV irradiation of solid potassium nitrate induces partial photoisomerisation to potassium peroxonitrite, which has been previously reported to generate hydroxyl radicals during dissolution in aqueous solution. Support for hydroxyl radical generation was obtained and the hydroxyl radical was observed to be a key intermediate for strong chemiluminescence of luminol during dissolution of irradiated KNO3 in luminol sample solutions. Both lyoluminescence systems allow the detection of luminol down to sub-nM levels with linear calibration curves spanning five orders of magnitude of luminol concentration, suggesting that they can be used as tools in bioaffinity assays utilising luminol and isoluminol derivatives as labels.

Process for producing potassium nitrate

Abstract: The present invention relates to a production process of potassium nitrate, including the following steps: the nitric acid aqueous solution, potassium chloride and magnesium oxide are added in reactor, the obtained reaction product mixture is filtered and naturally cooled to extract potassium nitrate crystal, and the residual mother liquor is frozen to-10--30 deg.C, and reused for extracting potassium nitrate crystal, then the above-mentioned twice extracted crystals are mixed, washed with water, dewatered and dried so as to obtain the potassium nitrate product. Said invention is simple in preparation process and low in cost.

Granular magnesium oxide fertilizer

Abstract: PROBLEM TO BE SOLVED: To obtain a granula magnesium oxide fertilizer excellent in disintegrating properties in water and in soil borne and low in segregation when used as a component of bulk blend fertilizer composed by granulating the mixture of a specific magnesium raw material and specific metal salt. SOLUTION: This granules are composed by granulating the mixture of magnesium oxide or magnesium raw material having magnesium oxide as a principle ingredient and preferably a salt of a monovalent inorganic acid and a monovalent metal preferably the metal is sodium or potassium (e.g.: potassium nitrate). Preferably 5-80wt.% of metal salt is contained. This graular magnesium oxide fertilizer is obtained by granulating the mixture of magnesium oxide or magnesium raw material with a metal salt using water as a granulating agent, drying the granules at 60-120 deg.C and cooling.

Optimized nitrate reductase assay predicts the rate of nitrate utilization in the halotolerant microalga Dunaliella viridis

Abstract: An in situ method for measuring nitrate reductase (NR) activity in Dunaliella viridis was optimized in terms of incubation time, concentration of KNO3, permeabilisers (1-propanol and toluene), pH, salinity, and reducing power (glucose and NADH). NR activity was measured by following nitrite production and was best assayed with 50 mM KNO3, 1.2 mM NADH, 5% 1-propanol (v/v), at pH 8.5. The estimated half-saturation constant (Ks) for KNO3 was 5 mM. Glucose had no effect as external reducing power source, and NADH concentrations >1.2 mM inhibited NR activity. Nitrite production was linear up to 20 min; longer incubation did not lead to higher nitrate reduction. The use of the optimized assay predicted the rate of NO 3 − removal from the external medium by D. viridis with high degree of precision.

Aqueous solution for forming titanium oxide film, and production of titanium oxide film

Abstract: PROBLEM TO BE SOLVED: To obtain an aqueous solution capable of easily forming a titanium oxide film of uniform film thickness and composition even on a substrate of large area and complicated shape without requiring large-sized equipment by providing an aqueous solution containing a titanium ion, a nitric acid ion, a peroxide, and a complexing agent and having a specific pH value. SOLUTION: A titanium oxide film is formed by using an aqueous solution which contains a titanium ion, a nitric acid ion, a peroxide, and a complexing agent by about (0.001 to 1.0) mol/l, respectively, and in which pH value is regulated to >=3.0. As a titanium ion source, water soluble titanate, such as titanium trichloride and titanium tetrachloride, is used. As nitrate ion source, nitric acid, sodium nitrate, potassium nitrate, ammonium nitrate, etc., are used. Further, as a peroxide, hydrogen peroxide, peroxoacid, peroxocarbonate, peroxophosphate, peroxoborate, etc., are preferred. As a complexing agent, EDTA salt, citric acid salt, nitrotriacetate, and cyclohexanediaminetetraacetic acid, etc., are preferred. The above film can be formed by means of electrolytic deposition in the aqueous solution.