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Combinations of chemical compounds that reportedly reduce the corrosion of aluminum in fresh water were evaluated. These included combinations of borates, nitrates, nitrites, phosphates, silicates, and mercaptobenzothiazole. Eight of fifty inhibitor combinations evaluated gave excellent corrosion protection and compared favorably with sodium chromate, which has generally been considered standard for many years.
Reactions between nitrogen and water in the air surrounding lightning discharges can provide an important source of nitric oxide even under conditions where oxygen is a minor atmospheric constituent. Estimates are given for the associated source of soluble nitrite and nitrate. It is shown that lightning and subsequent atmospheric chemistry can provide a source of nitrate for the primitive ocean as large as one million tons of nitrogen per year, sufficient to fill the ocean to its present level of nitrate in less than one million years.
Thermodynamic quantities for the gas-phase clustering equilibria of NO2(-) and NO3(-) were determined with high-pressure mass spectrometry. A comparison of values of the free energy of hydration derived from the data shows good agreement with formerly reported values at 296 K. New data for larger NO2(-) and NO3(-) hydrates as well as NO2(-)(HNO2)n were obtained in this study. To aid in understanding the bonding and stability of the hydrates of nitrite and nitrate ions, CNDO/2 calculations were performed, and the results are discussed. A correlation between the aqueous-phase total hydration enthalpy of a single ion and its gas-phase hydration enthalpy was obtained. Atmospheric implications of the data are also briefly discussed.
The influence of oxygen concentration on the production of NO2(-) and N2O by nitrifying marine bacteria of the genus Nitrosomonas is investigated. Pure cultures of the ammonium-oxiding bacteria isolated from the Western Tropical Atlantic Ocean were grown at oxygen partial pressures from 0.005 to 0.2 atm, and concentrations of N2O in the air above the growth medium and dissolved NO2(-) were determined. Decreasing oxygen concentrations are observed to induce a marked decrease in NO2(-) production rates and increase in N2O evolution, leading to an increase of the relative yield of N2O with respect to NO2(-) from 0.3% to nearly 10%. Similar yields of N2O at atmospheric oxygen levels are found for nitrifying bacteria of the genera Nitrosomonas, Nitrosolobus, Nitrosospira and Nitrosococcus, while nitrite-oxydizing bacteria and a dinoflagellate did not produce detectable quantities of N2O. Results support the view that nitrification is a major source of N2O in the environment.
A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults.
Upper atmospheric research programs in the department of chemical kinetics are reported. Topics discussed include: (1) third-order rate constants of atmospheric importance; (2) a computational study of the HO2 + HO2 and DO2 + DO2 reactions; (3) measurement and estimation of rate constants for modeling reactive systems; (4) kinetics and thermodynamics of ion-molecule association reactions; (5) entropy barriers in ion-molecule reactions; (6) reaction rate constant for OH + HOONO2 yields products over the temperature range 246 to 324 K; (7) very low-pressure photolysis of tert-bytyl nitrite at 248 nm; (8) summary of preliminary data for the photolysis of C1ONO2 and N2O5 at 285 nm; and (9) heterogeneous reaction of N2O5 and H2O.
Laboratory tests were performed to quantify the expected NO(x) production by lightning and biological processes. Attention was focused on energy deposition by lightning and the oxygen partial pressure of soil, and one-dimensional photochemical models were defined for the tropospheric distributions of NO and HNO3 for various NO source strengths. The Lightning Facility data were compared with air samples of N2O production gathered during over 2 yr of flights through storms. Soil NO(x) productions were studied in terms of nitrification processes involving Nitrosomonas europaea and Alcaligenes faecalis bacteria, which change ammonium to nitrite and release NO and N2O as byproducts. The results indicate that atmospheric NO(x) is generated at two tropospheric levels, with lightning and soil bacteria being significant contributors.
Extremely halophilic bacteria were isolated from widely separated sites by anaerobic enrichment in the presence of nitrate. The anaerobic growth of several of these isolates was accompanied by the production of nitrite, nitrous oxide, and dinitrogen. These results are a direct confirmation of the existence of extremely halophilic denitrifying bacteria, and suggest that such bacteria may be common inhabitants of hypersaline environments.
The ability of Halobacterium vallismortis, Halobacterium mediterranei and Halobacterium marismortui (Ginzburg strain) to grow anaerobically and denitrify was determined. Each organism grew anaerobically only in the presence of nitrate. H. marismortui produced nitrite and dinitrogen from nitrate during exponential growth. However, as the culture entered stationary phase, dinitrogen production ceased and nitrous oxide was detected. H. vallismortis produced nitrous oxide and dinitrogen during exponential growth, with dinitrogen production ceasing at the onset of stationary phase. H. mediterranei produced dinitrogen during exponential growth and did not produce nitrous oxide. These results confirm the occurrence of denitrification in the halobacteria.
Seasonal and diurnal emissions of NO and N2O from agricultural sites in Jamestown, Virginia and Boulder, Colorado are estimated in terms of soil temperature; percent moisture; and exchangeable nitrate, nitrite, and ammonium concentrations. The techniques and procedures used to analyze the soil parameters are described. The spatial and temporal variability of the NO and N2O emissions is studied. A correlation between NO fluxes in the Virginia sample and nitrate concentration, temperature, and percent moisture is detected, and NO fluxes for the Colorado site correspond with temperature and moisture. It is observed that the N2O emissions are only present when percent moisture approaches or exceeds the field capacity of the soil. The data suggest that NO is produced primarily by nitrification in aerobic soils, and N2O is formed by denitrification in anaerobic soils.
Nitrous oxide (N2O) flux from vented chambers was measured over intensively and minimally managed bermuda grass hay meadows in a humid, subtropical ecosystem for several years during scheduled sampling protocol following harvest, fertilization and rainfall events while measuring diel N2O emissions once during each of 5 seasonal day growth cycles which divided each calendar year. Soil pools of nitrite NO2(-), nitrate NO3(-), and ammonia (NH3) were measured in soil samples taken at 2 and 10 cm depths during each emission collection to determine transformations of the nitrogen pools coupled with N2O emissions. The highest diel N2O emission occur midday in the Spring cycle, measuring 9.0 g N/ha/d only for several weeks, while emissions dropped to less than 1.0 g N/ha/day during hot, dry, and colder months. Intensively managed meadows (4 fertilizations and harvests per year plus pest management) induced higher seasonal N2O emissions than minimal treatment (1 fertilization and harvest) averaging 2.75 and 5.97 g N/ha/day. Nitrous oxide emission data as responses to soil parameters and environmental parameters were also measured where air temperature, soil moisture, and fertilization were the most powerful factors.
An electron transport regulatory gene, etrA, has been isolated and characterized from the obligate respiratory bacterium Shewanella putrefaciens MR-l. The deduced amino acid sequence of etrA (EtrA) shows a high degree of identity to both the Fnr of Escherichia coli (73.6%) and the analogous protein (ANR) of Pseudomonas aeruginosa (50.8%). The four active cysteine residues of Fnr are conserved in EtrA, and the amino acid sequence of the DNA-binding domains of the two proteins are identical. Further, S.putrefaciens etrA is able to complement an fnr mutant of E.coli. In contrast to fnr, there is no recognizable Fnr box upstream of the etrA sequence. Gene replacement etr.A mutants of MR-1 were deficient in growth on nitrite, thiosulfate, sulfite, trimethylamine-N-oxide, dimethyl sulfoxide, Fe(III), and fumarate, suggesting that EtrA is involved in the regulation of the corresponding reductase genes. However, the mutants were all positive for reduction of and growth on nitrate and Mn(IV), indicating that EtrA is not involved in the regulation of these two systems. Southern blots of S.putrefaciens DNA with use of etrA as a probe revealed the expected etrA bands and a second set of hybridization signals whose genetic and functional properties remain to be determined.
The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: (1) directing a vapor stream containing at least nitrogen-containing oxidizing agent to a first contact zone; (2) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen- containing oxidizing agent; (3) directing said acid(s) as a second stream to a second contact zone; (4) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrite form present within said second stream to nitrate ion; (5) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; (6) adding hydrogen peroxide to said second contact zone when a level on hydrogen peroxide less than 0.1% by weight in said second stream is determined by said sampling; (7) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and (8) removing sais solution of potassium nitrate from said second contact zone.
Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.
A comparison of monthly biogeochemical measurements made from 1993 to 1995, combined with hydrography and satellite altimetry, was used to observe the impacts of nine eddy events on primary productivity and particle flux in the Sargasso Sea. Measurements of primary production, thorium-234 flux, nitrate+nitrite, and photosynthetic pigments made at the US JGOFS Bermuda Atlantic Time-Series Study (BATS) site were used. During the three years of this study, four out of six high thorium-234 flux events over 1000 dpm/sq m/d occurred during the passage of an eddy. Primary production nearly as high as the spring bloom maximum was observed in two mode-water eddies (May 1993 and July 1995). The 1994 spring bloom at BATS was suppressed by the passage of an anticyclone. Distinct phytoplankton community shifts were observed in mode-water eddies, which had an increased percentage diatoms and dinoflagelletes, and in cyclones, which had an increased percentage cyanobacteria (excluding Prochlorococcus). The difference in the observations of mode-water eddies and cyclones may result from the age of the eddy, which was very important to the biological response. In general, eddies that were one to two months old elicited a large biological response; eddies that were three months old may show a biological response and were accompanied by high thorium flux measurements; eddies that were four months old or older did not show a biological response or high thorium flux. Our conceptual model depicting the importance of temporal changes during eddy upwelling and decay fit the observations well in all seven upwelling eddies. Additional information is needed to determine the importance of deeper mixed layers and winter mixing to the magnitude of the eddy impacts. Also, sampling generally captured only the beginning, end, and/or edge of an eddy due to the monthly to semi-monthly frequency of the measurements made at BATS. Lagrangian studies, higher resolution time-series, and/or more spatial coverage is needed to provide additional information for improved C and N budgets in the Sargasso Sea and to complete our understanding of the temporal changes that occur in an eddy.
A mesoscale eddy advected across the Bermuda Testbed Mooring site over a 30-day period centered on July 14, 1995. Temperature and current measurements along with biogeochemical measurements were used to characterize the biological response of the upper ocean associated with the introduction of nitrate into the euphotic layer due to the doming of isotherms associated with the eddy. Complementary shipboard data showed an anomalous water mass, which extended from a depth of approximately 50 to 1000 m, manifesting as a cold surface expression and warm anomaly at depth. Although mesoscale eddies are frequently observed in the Sargasso Sea, the present observations are particularly unique because of the high-temporal-resolution measurements of the new instrumentation deployed on the mooring. Analyzers that measure nitrate plus nitrite were placed at depths of 80 and 200 m and bio-optical sensors were located at depths of 20, 35, 45, 71, and 86 m. Peak nitrate values of nearly 3.0 micro-M at 80 m and chlorophyll a values of 1.4 mg/cubic m at 71 m were observed, a well as a 25- to 30-meter shoaling of the 1% light level depth. A Doppler shift from the inertial period (22.8 hours) to 25.2 hours was observed in several time series records due to the movement of the eddy across the mooring. Inertial pumping brought cold, nutrient-rich waters farther into the euphotic zone than would occur solely by isothermal lifting. Silicic acid was depleted to undetectable levels owing to the growth of diatoms within the eddy. The chlorophyll a values associated with the eddy appear to be the largest recorded during the eight years of the ongoing US JGOFS Bermuda Atlantic Time Series Study program.
Alpha-hydroxy and alpha-amino carboxylic acids found on the Murchison meteorite are deuterium enriched. It is postulated that they arose from a common interstellar scurce: the reaction of carbonyl compounds in an aqueous mixture containing HCN and NH3. Carbonyl compounds react with HCN to form alpha-hydroxy nitriles, RR'CO + HCN right and left arrow RR'C(OH)CN. If ammonia is also present, the alpha-hydroxy nitriles will exist in equilibrium with the alpha-amino nitriles, RR'C(OH)CN + NH3 right and left arrow - RRCNH2CN + H2O. Both nitrites are hydrolyzed by water to form carboxylic acids: RR'C(OH)CN + H2O yields RR'C(OH)CO2H and RR'C(NH2)CN + H2O yields RR'C(NH2)CO2H.
A mesoscale eddy advected across the Bermuda Testbed Mooring site over a 30-day period centered on July 14, 1995. Temperature and current measurements along with biogeochemical measurements were used to characterize the biological response of the upper ocean associated with the introduction of nitrate into the euphoric layer due to the doming of isotherms associated with the eddy. Complementary shipboard data showed an anomalous water mass, which extended from a depth of approximately 50 to 1000 m, manifesting as a cold surface expression and warm anomaly at depth. Although mesoscale eddies are frequently observed in the Sargasso Sea, the present observations are particularly unique because of the high-temporal-resolution measurements of the new instrumentation deployed on the mooring. Analyzers that measure nitrate plus nitrite were placed at depths of 80 and 200 m and bio-optical sensors were located at depths of 20, 35, 45, 71, and 86 m. Peak nitrate values of nearly 3.0 microns at 80 m and chlorophyll alpha values of 1.4 mg/cu m at 71 m were observed, as well as a 25- to 30-meter shoaling of the 1% light level depth. A Doppler shift from the inertial period (22.8 hours) to 25.2 hours was observed in several time series records due to the movement of the eddy across the mooring. Inertial pumping brought cold, nutrient-rich waters farther into the euphotic zone than would occur solely by isothermal lifting. Silicic acid was depleted to undetectable levels owing to the growth of diatoms within the eddy. The chlorophyll alpha values associated with the eddy appear to be the largest recorded during the 8 years of the ongoing U.S. JGOFS Bermuda Atlantic Time Series Study (BATS) program.