Showing papers on "Ammonia published in 1974"

Effect of ammonia concentration on rumen microbial protein production in vitro

Abstract: 1. The effect of ammonia concentration on microbial protein production was determined in continuous-culture fermentors charged with ruminal contents obtained from steers fed on either a protein-free purified diet, a maize-based all-concentrate diet, or a forage–concentrate (23:77) diet. Urea was infused into the fermentors to maintain various concentrations of ammonia in the incubating mixtures.2. Under nitrogen-limiting conditions, microbial protein yield measured as tungstic acid-precipitable N (TAPN) increased linearly with supplementary urea until ammonia started to accumulate in the incubating ingesta. Increasing the ammonia concentration beyond 50 mg NH3-N/l had no effect on microbial protein production.3. The molar proportions of volatile acids produced were not affected by the level of urea supplementation. Total acid production was decreased slightly under N-limiting conditions, but not to the same extent as microbial protein production.4. Estimated yield of microbial dry matter/mol ATP produced averaged 15·6 when non-limiting N as urea was provided with the purified diet.5. These results suggest that addition of non-protein N supplements to ruminant rations are warranted only if the prevailing concentration of ruminal ammonia is less than 50 mg NH3-N/l ruminal fluid.

Ammonia or ammonium ion as substrate for oxidation by Nitrosomonas europaea cells and extracts.

Abstract: The effect of pH on the Km values for ammonia was studied in its oxidation by Nitrosomonas cells and cell-free extracts The Km values decreased markedly with increasing pH, suggesting (NH3) rather than (NH4+) as the actual substrate for oxidation

Chemiluminescent ammonia detection

Abstract: Ammonia content of a gaseous mixture is determined by converting the ammonia to nitric oxide and measuring the nitric oxide. A gaseous mixture sample is passed through a heated mixture of oxides of platinum group metals and/or copper oxide together with vitreous carbon whereby any gaseous ammonia is converted catalytically into nitric oxide. Using the chemiluminescent analysis technique, the ammonia content of the gaseous mixture sample may be monitored in a suitable instrument.

Photoinactivation of Ammonia Oxidation in Nitrosomonas

Abstract: Photoinactivation of ammonia oxidation in cells of Nitrosomonas was shown to follow first-order kinetics with a rate constant proportional to incident light intensity. The action spectrum for photoinactivation consisted of a broad peak in the ultraviolet range, where both hydroxylamine and ammonia oxidation were affected, and a shoulder at approximately 410 nm where only ammonia oxidation was affected. In photoinactivated cells, hydroxylamine but not ammonia was oxidized to nitrite and hydroxylamine but not ammonia caused reduction of cytochromes in vivo. The amount per cell of the following constituents was not measurably altered by photoinactivation: cytochromes b, c, a, and P460; ubiquinone; phospholipid; free amino acids; hydroxylamine-dependent nitrite synthetase; nitrite reductase; p-phenylenediamine oxidase; and cytochrome c oxidase. Malonaldehyde or lipid peroxides were not detected in photoinactivated cells. Photoinactivation was prevented (i) under anaerobic conditions, (ii) in the presence of methanol, allylthiourea, thiosemicarbazide, hydroxylamine, ethylxanthate, or CO at concentrations wich caused 100% inhibition of ammonia oxidation, and (iii) at concentrations of ammonia or hydroxylamine which gave a rapid rate of nitrite production. Recovery of ammonia oxidation activity in 90% inactivated cells took place in 6 h, required an energy and/or nitrogen source, and was inhibited by 400 mug of chloramphenicol per ml.

Sulfuric Acid-Ammonium Sulfate Aerosol: Optical Detection in the St. Louis Region

Abstract: Nephelometric sensing of the deliquescence of ammonium sulfate produced by the reaction of sulfuric acid or ammonium bisulfate aerosol with ammonia provides a means for detecting these substances in air. Field experiments show them to be the dominant substances in the submicrometer, light-scattering aerosol in the St. Louis region.

Effects of nitrification inhibitors on transformations of urea nitrogen in soils

Abstract: The effects of three patented nitrification inhibitors on transformations of urea N in soils were studied by determining the effects of these compounds (10 μg/g of soil) on urea hydrolysis, ammonia volatilization. and production of ammonium, nitrite, and nitrate in soils incubated under aerobic conditions (30°C, 60% WHC) after treatment with urea (400 μg of urea N/g of soil). The inhibitors used (N-Serve, ATC, and CL-1580) had little, if any, effect on urea hydrolysis, but they retarded nitrification of the ammonium formed by urea hydrolysis and increased gaseous loss of urea N as ammonia. They also decreased the amount of (urea + exchangeable ammonium + nitrite + nitrate) — N found in urea-treated soils after various times. Two of the soils used accumulated substantial amounts of nitrite(> 160 μg of nitrite N/g of soil) when incubated under aerobic conditions after treatment with urea. Addition of nitrification inhibitors to these soils eliminated or substantially reduced nitrite accumulation and greatly retarded nitrate formation, but had little, if any, effect on the recovery of urea N as (urea + exchangeable ammonium + nitrite + nitrate + ammonia) — N after various times. This finding and other observations reported indicate that the “nitrogen deficits” observed in studies of urea N transformations in soils may not largely be due to gaseous loss of urea N through chemodenitrification and are at least partly due to volatilization and fixation of the ammonium formed by urea hydrolysis in soils. The work reported also indicates that N-Serve and other nitrification inhibitors may prove useful for reduction of the nitrite toxicity problems associated with the use of urea as a fertilizer but that application of such inhibitors in conjunction with fertilizer urea, when surface applied, may promote gaseous loss of urea N as ammonia.

Effects of Ammonium, l-Glutamate, and l-Glutamine on Nitrogen Catabolism in Aspergillus nidulans

Abstract: During growth of Aspergillus nidulans in medium containing ammonium the specific activities of most enzymes involved in catabolism of nitrogen sources are low (ammonium repression). The gdhA10 lesion, which results in loss of nicotinamide adenine dinucleotide phosphate-linked glutamate dehydrogenase activity, has been shown to lead to partial relief of ammonium repression of three amidase enzymes as well as histidase. The areA102 lesion led to altered levels of these enzymes but did not greatly affect ammonium repression. The double mutant areA102,gdhA10 was almost completely insensitive to ammonium repression of two of the amidase enzymes and histidase. This suggests that an interaction between the areA and gdhA genes in determining responses to ammonium occurs. Growth of mycelium in medium containing l-glutamate has been found to result in lowered levels of all four enzymes, and this occurs in strains insensitive to ammonium repression. Very strong repression in all strains occurred during growth in medium containing l-glutamine. Relief of these repressive effects of glutamate and glutamine was blocked by cycloheximide. Glutamate and glutamine had similar effects on the production of extracellular protease activity, and growth on glutamine led to low levels of urate oxidase. In contrast to the above enzymes, nitrate reductase was insensitive to the effects of glutamine and glutamate, even though this enzyme is very sensitive to ammonium repression. Although other possibilities exist, it is suggested that there may be mechanisms of general control of nitrogen-catabolic enzymes other than ammonium repression.

Reduction of nitrogen oxides with catalytic acid resistant aluminosilicate molecular sieves and ammonia

Abstract: Noxious nitrogen oxides in a waste gas stream such as the stack gas from a fossil-fuel-fired power generation plant or other industrial plant off-gas stream is catalytically reduced to elemental nitrogen and/or innocuous nitrogen oxides employing ammonia as reductant in the presence of a zeolite catalyst in the hydrogen or sodium form having pore openings of about 3 to 10 A.

Process for selective reduction of oxides of nitrogen

Abstract: Oxides of nitrogen are selectively removed from air-polluting exhaust gases from nitric acid manufacturing plants by reaction with preferably a stoichiometric amount of ammonia in the presence of an acid-resistant aluminosilicate molecular sieve composition as catalyst.

The Effect of Phenols and Heterocyclic Bases on Nitrification in Activated Sludges

Abstract: Summary. Activated sludge receiving ammonium thiocyanate (500 mg/l) was able to nitrify. The rate of ammonia oxidation was decreased when >3 mg/l of phenol (or cresols) was added to the sludge, and at 10 mg/l was inhibited completely. Concentrations of up to 100 mg/l of phenols did not affect nitrite oxidation. The 2- and 4-methyl pyridine derivatives inhibited both ammonia and nitrite oxidation.

Titratable acid, PCO2, bicarbonate and ammonium ions along the rat proximal tubule.

Abstract: The proximal tubule of cortical nephrons of male albino rats were studied. The intratubular pH was measured with antimony microelectrodes. The concentrations of bicarbonate ions, the ammonium ions and titratable acid were measured in the same free flow samples from single tubules, using a recently developed ultramicroanalytical system, which also permits the estimation of intratubular Pco2. The concentration of titratable acid, which is thought mainly to emanate from phosphate, was found to be constant, about 1 mM, along the proximal tubule. This is explained as a gradient limited transport process for phosphate as well as for hydrogen ions. The concentration of ammonium ions was found to be about 2 mM along the convoluted proximal tubule in spite of water reabsorption, indicating some reabsorptive mechanisms for ammonium or the base, ammonia. Furthermore the present investigation indicates a high Pco2 in the untreated proximal tubule which could explain the phenomenon of disequilibrium pH.

Desulfurization process for hydrogen sulfide containing gases

Abstract: In a process for desulfurizing hydrogen sulfide-containing gases by contacting a hydrogen sulfide-containing gas with an alkaline aqueous solution containing a naphthoquinonesulfonate to effect absorption of hydrogen sulfide by said aqueous solution and subjecting the effluent to catalytic oxidation by a molecular oxygen-containing gas to separate out sulfur, an improvement which comprises (a) carrying out the absorption of hydrogen sulfide by using a liquid absorbent having a pH value adjusted by means of ammonia to 8 to 10 and containing as catalyst components a naphthoquinonesulfonate and a variable valent metal compound, (b) carrying out the catalytic oxidation of the effluent containing absorbed therein hydrogen sulfide by means of a molecular oxygen-containing gas as to lower the concentration of hydrosulfide ion in the effluent to 70 ppm or less and (c) recirculating the said liquid absorbent or effluent to the contact with the said hydrogen sulfide-containing gas.

Determination of ammonium nitrogen in animal slurries by an ammonia electrode

Abstract: Ammonium nitrogen in animal slurries can be determined using an Orion ammonia electrode. Dilute hydrochloric acid (0.1N HCl) is used to extract the ammonium nitrogen from the slurries. The electrode method of analysis is simple, rapid and precise and gives quantitative recovery of added ammonium. Results agree closely with the standard steam distillation‐titration method.

Diaper resistant to ammonia odor formation

Abstract: A diaper treated with a hydroxamic acid in an amount sufficient to inhibit the decomposition of urea to ammonia when wetted with urine.

Extracting tea using an aqueous solution of ammonium bicarbonate or ammonia

Abstract: The yield in the aqueous extraction of tea leaf is improved by using an aqueous solution of ammonium bicarbonate or of ammonia as the extractant.

Nitrogen metabolism in the american cockroach: an examination of whole body ammonium and other cations excreted in relation to water requirements

Abstract: The effects of dietary nitrogen levels in relation to ammonotelism, cation excretion and water requirements were examined in the American cockroach, Periplaneta americana (L.). Very little ammonia is released from the respiratory surfaces; rather it appears to be eliminated in the faeces, presumably as ammonium ions. Microflora present in the hindgut may contribute significantly to the production of excreted ammonia under certain dietary conditions. Injections of buffers containing either NH 4 +, K+ or Na+ resulted in normal (NH 4 + and K+), or less than normal (Na+) levels of ammonia excretion. Faeces collected from cockroaches maintained on twelve different diets containing various levels and sources of nitrogen were examined for NH 4 +, K+, Na+, Ca2+ and Mg2+. Ammonium ions were found to be the major cations contained in the faeces and were excreted in increasing amounts as the dietary nitrogen levels increased. The ad libitum water requirements were closely correlated with dietary nitrogen levels, and subsequently with ammonia excretion. Certain aspects concerning the possible factors involved, and the significance of ammonia excretion, are discussed.

Process of producing alkali metal or ammonium citrates

Abstract: Alkali metal or ammonium citrates are produced from solutions of citric acid obtained by chemical reaction or by fermentation by extraction by means of a specific water-immiscible mixture of aliphatic amines and organic solvents and re-extracting the resulting organic solvent mixture with an aqueous solution of an alkali metal hydroxide, carbonate or bicarbonate, ammonia, or their salts.

Low to high temperature energy conversion system

Abstract: One embodiment of a low to high temperature energy conversion system includes a decomposition chamber in which ammonia (NH3) is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature, e.g., 300° C energy source. The separated hydrogen and nitrogen are then supplied to a recombination chamber wherein they recombine to produce ammonia. The recombination process is associated with a significant increase in temperature, used to increase the temperature of a fluid to temperatures on the order of 500° C.

The thermal decomposition of ammonium metavanadate

Abstract: On heating, ammonium metavanadate (AMV) decomposes in several atmospheredependent stages. An important decomposition intermediate, ammonium hexavanadate (AHV), may also be prepared by wet-chemical methods and the kinetic parameters for the thermal decomposition of AMV and of the AHV preparation have been obtained. The kinetic study has been supplemented by surface-area measurements and by electron microscopic examination of the surfaces of reactant, intermediate and product crystallites. On the basis of the type of decomposition curve, the measured activation energies, and the effects of oxygen and water vapour on the decomposition rate, it has been concluded that in vacuum and in inert atmospheres the evolution of ammonia is the rate-determining step, while in oxidizing atmospheres evolution of water is rate determining. Comparison of the kinetic parameters with thermodynamic data for the decomposi. tion has led to suggestions as to the nature of the activated complexes involved.