Showing papers on "Potassium nitrate published in 1996"

Plasma nitrate as an index of nitric oxide formation in man: analyses of kinetics and confounding factors.

Abstract: Nitric oxide (NO) is metabolized to nitrate in humans. Accordingly, plasma nitrate has been proposed as an index of the in vivo formation of NO. Such an application requires knowledge about the possible influence of nitrate from sources other than endogenous NO formation, as well as of the kinetics of nitrate in plasma. In the present study, plasma nitrate increased from 32 +/- 4 to 205 +/- 27 mumol/l (mean +/- SE) following intake of nitrate-rich food. It dropped during the intake of nitrate-restricted diet and stabilized at a level of 29 +/- 1 mumol/l. The urinary excretion of nitrate during nitrate restriction was 840 +/- 146 mumol/24 h. Plasma nitrate was not affected following the intake of a gastrointestinal antibiotic drug for a period of four days. Smoking three cigarettes in succession did not affect the plasma nitrate levels significantly. The oral intake of potassium nitrate (500 mg approximately 4950 mumol) elevated plasma nitrate from 29 +/- 3 to 313 +/- 12 mumol/l within 60 min. The subsequent drop in plasma nitrate, with a t1/2 of 451 +/- 42 min, was probably a reflection of the redistribution of nitrate within the body fluids and the renal excretion of nitrate. The plasma clearance of nitrate was 30 +/- 2 ml/min/1.73 m2 BSA. The distribution volume for nitrate was 28 +/- 1% of the bodyweight (BW). We conclude that plasma nitrate can be used as an index of the endogenous formation of NO, provided that the oral intake of nitrate is restricted for at least 48 h. Due to the large distribution volume and the low clearance of the ion wide-spread, marked, and chronic changes in NO formation are required to significantly affect the levels of nitrate in samples of mixed blood.

Syntheses of pure tetramethylammonium peroxynitrite.

Abstract: Publisher Summary This chapter discusses the synthesis of pure tetramethylammonium peroxynitrite. The synthesis is based on a biomimetic strategy in which tetramethylammonium superoxide is reacted directly with nitric oxide. The use of ammonia as the solvent and tetramethylammonium superoxide as the superoxide source is critical in this synthesis. The synthesis of tetramethylammonium peroxynitrite, [N(CH3)4][ONOO], as a pure, stable, bright yellow salt. Other preparations of peroxynitrite include (1) hydrogen peroxide and nitrite ester in base, (2) the solid-state preparation by ultraviolet (UV) photolysis of potassium nitrate to give 30μmol of ONOOK per gram as a solid mixture of peroxynitrite and nitrate, and (3) the reaction of sodium azide and ozone. The reaction between tetramethylammonium hydroxide pentahydrate and potassium superoxide is a solid-phase reaction that is performed under vacuum and that requires efficient mixing and relatively long reaction times. When prepared under dry and maintained nitrogen, tetramethylammonium peroxynitrite is stored for several months with little detectable decomposition.

Activity coefficients of sodium, potassium, and nitrate ions in aqueous solutions of NaNO3, KNO3, and NaNO3+KNO3 at 25°C

Abstract: Ion selective electrodes have been used to measure the activity coefficients at 25°C of individual ions in aqueous solutions of NaNO3 up to 3.5 molal, KNO3 up to 3.5 molal and mixtures of NaNO3 and KNO3 up to 2.4 molal total nitrate ion concentration. The experimental results confirm that the activity coefficient of anion and cation in aqueous single electrolyte solutions of NaNO3 and KNO3 were different from each other over the whole range of concentrations studied. These effects are attributed to the ion-ion and ion-solvent interactions. The results also show that the activity coefficients of nitrate ions in the presence of sodium and potassium counterions do not depend significantly on the nature of the counterions present in the solution. The experimental data obtained in this study were correlated by a model proposed previously.

A pyrotechnic method of generating a particulate-free, non-toxic odorless and colorless gas

Abstract: An essentially particulate-free, non-toxic, odorless and colorless gas is generated in a pyrotechnic inflator device by using a eutectic solution of ammonium nitrate, guanidine nitrate and/or aminoguanidine nitrate, and minor amounts of polyvinyl alcohol and either potassium nitrate or potassium perchlorate. Ballistic modifiers such as triaminoguanidine nitrate (TAGN) or nitroguanidine (NQ) may be used as needed.

Phase Diagram for the System K2Cr2O7 + KNO3 + H2O in the Temperature Range 10 °C to 40 °C

Abstract: The phase diagram for the ternary system K2Cr2O7 + KNO3 + H2O was determined at four temperatures, (10, 20, 30, and 40) °C. In addition, the densities of the saturated aqueous solutions were measured. The experimental results show that, in the temperature range (10 to 40) °C, only potassium nitrate and potassium dichromate were present as solid phases and that the solubility of KNO3 was almost independent of the K2Cr2O7 concentration, whereas the solubility of K2Cr2O7 decreased sharply with increases in the concentration of KNO3.

Constant Composition Dissolution Kinetics Studies of Human Dentin

Abstract: The Constant Composition (CC) method has been used to study the dissolution kinetics of whole powdered human dentin as a function of calcium phosphate concentration at relative undersaturations with respect to hydroxyapatite (σHAP), ranging from +0.8 to -2.8, ionic strength from 0.05 to 0.30 mol/L-1 in sodium chloride or potassium nitrate, pH 4.00 to 5.50, and molar calcium/phosphate ratio in the reaction solutions from 0.05 to 11.1. The results suggest that human dentin behaves as a mixture of at least two calcium phosphate phases, HAP-like and octacalcium phosphate-like, OCP-like. Significant dissolution took place in solutions that were even supersaturated with respect to HAP, and the rates exhibited a striking insensitivity to relative undersaturation, while influenced by ionic strength, pH, and molar calcium/phosphate ratio in the reaction solutions. Although the dissolution was retarded in the presence of magnesium ion, the reaction rate showed the same insensitivity to undersaturation with respect ...

Process for the preparation of gas-generating compositions

Abstract: A process for the production of a gas-generating composition containing a redox-couple including a water soluble azide component, for example, azide of sodium, potassium, lithium, calcium or barium, and an oxidizer component, for example, sodium nitrate, sodium perchlorate, potassium nitrate, potassium perchlorate or an oxide of iron, nickel, vanadium, copper, titanium, manganese, zinc, tantalum, silicon or aluminium, said oxidizer component being capable of reacting with said azide component to generate gas, said process comprising the steps of: forming an aqueous dispersion of the redox-couple wherein the azide component is totally dissolved and the oxidizer is uniformly dispersed and stabilised in the azide solution; passing said aqueous dispersion through a spray nozzle to form a stream of droplets; and contacting said droplets with hot air whereby the water is removed to produce solid particles of gas-generating composition.

Isobaric Vapor−Liquid Equilibrium for Ethanol + Water + Strontium Nitrate

Abstract: Isobaric vapor−liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.642 has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.

Reversible liquid/solid phase change compositions

Abstract: Eutectic compositions of hydrated magnesium nitrate and either or both of sodium and potassium nitrate, as shown in the figure, are described and are useful as reversible liquid/solid phase change materials.

Eutectic mixtures of ammonium nitrate and amino guanidine nitrate

Abstract: An eutectic solution of ammonium nitrate and either aminoguanidine nitrate (AGN) or guanidine nitrate (AN) in the form of a present pellet is used to generate a particulate-free, non-toxic, odorless and colorless gas that is useful wherever an immediate source of such gas is required, such as the inflation of an occupant restraint air bag. The use of the material in the form of an eutectic totally eliminates pellet cracking. Moreover, the addition of a minor amount of potassium nitrate to the eutectic solution eliminates the ammonium nitrate phase change due to temperature cycling without adversely affecting the pressed pellets' freedom from cracking due to said temperature cycling.

Selection for mutants with low nitrate uptake ability in rice (Oryza sativa)

Abstract: Screening for mutants deficient in the high affinity system of nitrate uptake was performed using mutagenized M 2 population of rice (Oryza saliva, cv. Nipponbare or Kinmaze). For selecting mutants, M 2 seedlings were transferred individually to 10 ml solution containing 250 μM potassium nitrate and 500 μM calcium sulphate at 20 or 28°C. After 6 or 24 h, nitrate concentration of the solution was determined with a nitrate selective electrode and the seedlings showing impaired nitrate uptake were selected as nitrate uptake deficient variants. Of 74 variants, three were confirmed to be mutants with low nitrate uptake ability in the M 3 generation. Potassium uptake ability also decreased in the mutants. Three mutants were divided into two groups based on the analysis of nitrate reductase (NR, EC 1.6.6.1) activity and chlorate resistance. Two, NUE13 and NUE36, had a lower level of NR activity than the original cultivar and were not resistant to chlorate, while the seedlings of NUESO had the same level of NR activity as the original cultivar and were more resistant to chlorate than the original cultivar. All mutants were resistant to cesium, a toxic ion analogue for potassium, suggesting that the decreased levels of both nitrate and potassium uptake were coupled to the change of plasma membrane H + -ATPase activity.

Gas generating composition

Abstract: A solid composition for generating gases when ignited is a combination 5-aminotetrazole and at least two oxidizers selected from the group consisting of potassium nitrate, potassium per-chlorate, ferric oxide, copper oxide and manganese dioxide.

Solubility and Thermodynamics: An Introductory Experiment

Abstract: This article describes a laboratory experiment suitable for high school or freshman chemistry students in which the solubility of potassium nitrate is determined at several different temperatures. The data collected is used to calculate the equilibrium constant, delta G, delta H, and delta S for dissolution reaction. The simplifying assumptions are noted in the article.

Non-toxic fresh-preservative and preparation method thereof

Abstract: The non-toxic fresh-preservative for fresh flowers is prepared from alum, sodium benzoate, glucose, ascorbic acid, aspirin, zinc sulfate, ammonium, magnesium sulfate, potassium permanganate, sodium chloride, ferrous sulfate, potassium nitrate, urea and filler by pulverizing, fractional uniformly mixing, checking and packing. The finished product is water-soluble powder of 98% with blue-white colour, and is non-toxic. It has the advantage of simple technology, low cost, convenient preservation and transportation, wide-sepctrum etc..

Method for making nitrogen-potassium fertilizer containing calcium nitrate and products thereof

Abstract: The invention relates to a method for making NK-fertilizers basically from calcium nitrate fertilizers and potassium nitrate and homogeneous NK-fertilizer products. Calcium nitrate fertilizer is melted together with potassium nitrate to form a melt or suspension thereof which is particulated to form a homogeneous NK-fertilizer. The calcium nitrate fertilizer and the potassium nitrate are melted at 90-120 °C and then heated to the desired particulation temperature being 160-190 °C for prilling and 90-140 °C for granulation. The components are mixed in ratios giving a melt or suspension comprising 40-14 weight % calcium nitrate, 55-85 weight % potassium nitrate, 0.5-6 weight % water, 0-4 weight % ammonium nitrate and 0-5 weight % magnesium nitrate.

GN, AGN and KP gas generator composition

Abstract: The combination of guanidine nitrate (GN), aminoguanidine nitrate (AGN) and potassium perchlorate (KP) in defined proportions serves as an effective gas generative composition that displays enhanced burning rate performance at 2000 and 4000 psi. Through the addition thereto of small amounts of potassium nitrate (KN) the burning rate and pressure component of the composition is further improved and through the addition of polyvinyl alcohol (PVA) both greater dimensional strength and superior stability are provided.

Silver Sorption by Manganese Oxide

Abstract: Silver-manganese oxide ores are present in western United States, Mexico, South America, and Sumatra. The amount of silver varies between a few parts per million (ppm) to thousands of ppm. However, these ores are not compatible with conventional metallurgical treatment for the extraction of silver. This research is the study of the nature of silver binding with one model manganese oxide phase, cryptomelane. Cryptomelane is widely present in the United States and in parts of Colorado, with silver-bearing cryptomelane ore bodies containing up to a maximum of 1 wt% of silver. In order to better understand the nature of silver binding in cryptomelane, synthetic samples of cryptomelane were prepared and characterized, and then used for silver sorption experiments. The silver uptake appears to be a function of the solution chemistry conditions, pH and potassium nitrate concentration. The sorption of silver was found to increase with decreasing pH and at a fixed pH value, the sorption density was higher at a lower potassium nitrate concentration. Kinetics and equilibrium sorption data from lithium and sodium nitrate background electrolyte demonstrates three main results: firstly, most of the uptake of silver is compensated by release of potassium; secondly, the exchange for silver with protons and potassium ions is almost stoichiometric; and lastly, the importance of tunnel sites for the sorption reaction in cryptomelane. An ion-exchange model for the uptake of silver onto cryptomelane will also be discussed.

Thermal storage medium

Abstract: PURPOSE: To obtain the composition, containing sodium acetate trihydrate, potassium nitrate and ammonium nitrate in a specific proportion, excellent in fusion and solidification temperature suitability without phase separation, etc., in heat cycles for a long period and suitable for thermal storage systems, etc., for heating utilizing electric power. CONSTITUTION: This composition contains (A) 94-99wt.% sodium acetate trihydrate, (B) 0.5-3wt.% potassium nitrate and (C) 0.5-3wt.% ammonium nitrate. Furthermore, besides the components (A), (B) and (C), the composition further contains (D) sodium carbonate monohydrate and sodium pyrophosphate as a supercooling preventing agent in an amount of 1-15 pts.wt. based on the weight of the composition and (E) a polyglycerol in an amount of 1-15 pts.wt based on the weight of the composition.

A novel preparation of calcia fully stabilised zirconia from molten alkali-metal nitrate

Abstract: A novel preparation of cubic calcia stabilised zirconia (CaO–ZrO2) which employs the coprecipitation of the constituents from zirconium oxychloride (ZrO1.22Cl1.56) and calcium nitrate [Ca(NO3)2] with eutectic lithium nitrate-potassium nitrate (LiNO3–KNO3) at around 600 °C is described. The optimisation and advantages of the preparation are discussed.

Chemical constituents of Gossampinus malabarica (L.) Merr. (II)

Abstract: Four chemical compounds isolated from the root of Gossampinus malabarica were identified as daucosterol, oleanolic acid, hesperidin and potassium nitrate by physico-chemical constants and spectroscopic analysis.

Synthesis of K-Zr phosphates by the molten salt method

Abstract: Phosphates of K and Zr of a layered, microporous structure have been obtained by the molten salt method in a potassium nitrate medium in the temperatures range 573–823 K. Dependences of the product composition on the P/Zr atomic ratio and the temperature of synthesis were studied. The substances obtained have been characterized by XRD,1H and31P NMR, and IR spectroscopy, and scanning electron microscopy.

Thermal Studies on Boron-Based Initiator Formulation.

Abstract: Boron-potassium nitrate pyrotechnic composition can be converted into a hot wire-sensitive initiator formulation by the addition of an extra fuel. viz. lead thiocyanate. The ignition temperature of this composition depends on the percentage of thiocyanate in the mix and follows a binomial fit. The kinetic parameters. viz. activation energy E and pre-exponential factor A of the charge have been calculated from TG and DSC curves using different approaches developed by Coats-Redfern and Kissinger. Ignition delays measured from isothermal TG runs were found to yield equally good values of E and A. A comparison of these values for the tricomponent system' with those of the bicomponent systems as well as of the ingredients suggests that the starting reaction in this formulation is the reaction between lead thiocyanate and potassium nitrate which energises the main reaction between boron and potassium nitrate. leading to ignition.

Composition for fire suppression of large volumes of combustible liquids and gases

Abstract: FIELD: fire suppression of large volumes of combustible liquids and gases. SUBSTANCE: composition comprises potassium nitrate, dicyanoamide and iditol which are mixed and then compressed to relative density of 1300 kg/cu. m. Ratio of the components is as follows, wt.-%: 14-24 iditol; 20- 30 dicyanoamide and the potassium nitrate balance. The claimed invention makes it possible to decrease temperature of combustion products to 600 C and to retain fire suppression efficiency. EFFECT: improved properties of the composition. 2 tbl

Labelled compounds of interest as antitumour agents ‐ VI 1. Isotopically efficient syntheses of [15N]‐nitrothiophenecarboxamides

Abstract: Reaction of 3-cyanothiophene with one equivalent of potassium nitrate in concentrated sulphuric acid causes nitration, concurrent with hydrolysis of the nitrile, to give 5-nitrothiophene-3-carboxamide in high yield. Similarly, 2-cyanothiophene gives 4-nitrothiophene-2-carboxamide and 5-nitrothiophene-2-carboxamide, benzonitrile gives 3-nitrobenzamide and 4-methylbenzonitrile gives 4-methyl-3-nitrobenzamide. Extension of this process to use of potassium [ 15 N]-nitrate, formed from [ 15 N]-nitric acid (95% isotopic enrichment), enables preparation of the corresponding [ 15 N]-nitrothiophene-carboxamides in high isotopic yield.

Heat-resistant aerosol-forming composition for fire fighting

Abstract: FIELD: fire-fighting equipment. SUBSTANCE: fire-fighting heat-resistant composition generates during its burning the fire extinguishing substances and gaseous products which spray the fire extinguishing substances. The composition consists of heat-resistant components including 10-30% of fluoroplastic; 5-25% of high-energy fuel of the aluminum, magnesium, etc, type; the balance, potassium oxygen-containing compounds such as carbonate, oxalate, chromate, etc. The composition may additionally have an oxidizing additive in form of potassium nitrate and/or perchlorate in the amount of up to 50%. EFFECT: higher efficiency.