Wet Nitrogen Research Articles

Atmospheric input of inorganic nitrogen to the Western Mediterranean

Bulk inorganic nitrogen deposition was monitored over a period of 3 years at the Bavella Pass (Corsica, France). Annual fluxes range between 126 and 150μmol.m−2.d-−1, increasing slightly with annual rainfall. Natural background average concentrations of rain water and associated fluxes were estimated from a classification of rain events into ‘natural’ (Oceanic and Saharan), polluted and composite. Long range transport of incoming polluted air masses increases the atmospheric wet nitrogen input by at least a factor of 1.6 in this Mediterranean area. Extrapolation of atmospheric dissolved inorganic nitrogen input to the Western Mediterranean leads to fluxes of 80 to l00μmol.m−2.d-−1. This atmospheric input is in the same order of magnitude as the inorganic nitrogen riverine input. As a consequence, the nitrogen budget for the Mediterranean has had to be reassessed. Atmospheric wet inorganic nitrogen input is of noticeable importance to marine Mediterranean ecosystems, representing on average 10 to 25% of new production in the Western Basin, with values of up to 60% in oligotrophic zones.

Effect of steam on the coking of platinum catalysts: I. Inhibiting effect of steam at low partial pressure for the dehydrogenation of cyclopentane and the coking reaction

The effect of steam on the coking of Pt/Al 2O 3 was studied at 400°C under atmospheric pressure in the presence of cyclopentane in dry or wet (0.67 kPa of water) nitrogen. Steam decreases the coking rate, owing to the inhibition of the dehydrogenation of cyclopentane to cyclopentadiene, the main coke precursor. Temperature-programmed oxidation profiles of coke show three peaks: peak I at 275–320°C, peak II at 380–440°C and peak III at 480–550°C. Peak I is ascribed to carbon deposited on the metal whereas peaks II and III correspond to two different forms of coke deposited on the support. Steam decreases the amount of carbon oxidized at high temperature (500°C).

A study of TiO 2 powders as a support for the photochemical synthesis of ammonia

TiO 2 powder in either the rutile or the anatase form do not generate ammonia when they are subjected to ultraviolet irradiation under a wet nitrogen flux. In order to undergo this photochemical reaction, the samples first have to be annealed under air at atmospheric, high temperature. This treatment generates defect states in the band gap of the semiconductor and in the hydroxyl groups on the surface. The effects of thermal pretreatment on the various characteristics of the TiO 2 powders such as specific area, crystal structure, morphology and stoichiometry have been studied. The nature of the hydroxyl groups on TiO 2 surface is determined by IR spectrometry and by temperature-programmed desorption.

非酸化物セラミックスの高温水蒸気酸化

Nonoxide ceramics of hot-pressed AlN, hot-pressed Si3N4, sintered Si3N4, hot-pressed sialon and hot-pressed B4C were oxidized in wet nitrogen and/or wet air atmosphere at 1.5 to 20kPa of water vapor pressure and in dry air at 900-1400°C. All specimens were oxidized by both dry air and water vapor at high temperatures. AlN formed α-Al2O3 film on the surface above 1150°C. The oxidation rate of AlN increased with increasing water vapor pressure. The oxidation rate of AlN in wet nitrogen was much greater than that in wet air. Si3N4 and sialon formed oxide films consisting of SiO2, Y2Si2O7 and YAlO3. The oxidation kinetics obeyed the usual parabolic law. The oxidation rate in wet nitrogen, however, was unaffected by water vapor pressure and increased with increasing Y2O3 content. The apparent activation energy for the oxidation of Si3N4 based ceramics was about 800kJ/mol. On the other hand, since the oxidation of B4C by water vapor and dry air above 900°C resulted in weight loss, the formation of BO or HBO2 seemed to be the main reaction. The oxidation rate of B4C by water vapor above 900°C could be expressed by the surface chemical reaction controlled kinetics with the apparent activation energy of 200kJ/mol.

A comparison of the absorption from a ‘chemically defined elemental’ and a ‘whole protein’ enteral feed by the human small bowel

Absorption from the small intestine was studied in 10 patients with established ileostomies. Each patient was orally fed for two separate 7 day periods, one on a ‘chemically defined elemental’ enteral feed containing short-chain peptides and the other on a liquid ‘whole protein’ enteral feed. During both 7 day study periods each patient collected the total stoma effluent on days 4–7 inclusive. These were analysed for wet weight, nitrogen, sodium and potassium. Comparisons between the nutritional intake and ileostomy effluent showed no significant difference in the absorption by the small bowel of fluid, nitrogen and electrolytes from either preparation.

High-temperature oxidation of silicon nitride-based ceramics by water vapour

Hot-pressed Si3N4, sintered Si3N4 and three kinds of sialon with different compositions were oxidized in dry air and wet nitrogen gas atmospheres at 1100 to 1350° C and 1.5 to 20 kPa water vapour pressure. All samples were oxidized by both dry air and water vapour at high temperature, and formed oxide films consisting of SiO2, Y2Si2O7 and Y4A1209. The oxidation rate was in the order sialon > sintered Si3N4 > hot-pressed Si3N4. The oxidation rate of sialon increased with increasing Y2O3 content, and oxidation kinetics obeyed the usual parabolic law. The oxidation rates in dry air and wet nitrogen were almost the same: the rate in wet nitrogen was unaffected by water vapour pressure above 1.5 kPa. The activation energy was about 800 kJ mol−1.

High temperature oxidation of hot-pressed aluminium nitride by water vapour

Hot pressed AIN without additives was oxidized et 1100 to 1400°C in dry air, wet air and wet nitrogen gas atmospheres with 1.5 to 20 kPa of water vapour pressure. AIN was oxidized by both air and water vapour, and formed α-Al2O3 film on the surface above 1150°C. The oxidation kinetics in air were parabolic end were promoted by water vapour. On the other hand, the oxidation kinetics in wet nitrogen were linear below 1250°C and parabolic above 1350°C. The oxidation rate in wet nitrogen was much greater than that in wet air. The rate of oxidation increased with increasing temperature until 1350°C, and then decreased. The parabolic rate constant decreased with increasing temperature and increased linearly with increasing water vapour pressure. The linear rate constant at 1150 to 1250° C increased with increasing the temperature with the apparent activation energy of 250 kJ mol−1. The relation between the linear rate constant and water vapour pressure was of the Langmuir type.

Electrochemically activated wear of metal fibre brushes

The electrical and tribological properties of metal fibre sliding contacts are studied. The Cu-Cd fibres have a diameter of 50 μm. They slide on Cu-Cr tracks with optional surface treatments (gold electroplated on a nickel underplate). The working atmosphere is generally wet pure nitrogen. Several types of experimental results are reported in the first section. A microcomputer-controlled test bench is described first. It allows long duration tests on devices fitted with a large number of brushes. Results obtained with this set-up show that the temperature and the polarity of the electric field at the brush-track interface have an influence on the mechanisms and speed of wear. The electric field part is confirmed by complementary experiments where the current polarity is reversed. The electrochemical nature of the phenomena occurring at the sliding interface is then shown. In the second section the authors present a model adapted from Cabrera and Mott's copper oxidation theory. The part played by temperature and by the electrochemical electric field are described. After defining values for these two parameters, results obtained with the model are presented and are in very good agreement with the experimental results.

Internal gettering heat treatments and oxygen precipitation in epitaxial silicon wafers

As-received P/P + (100) epitaxial silicon wafers were heat treated using the one-, two-, and three-step internal gettering heat treatment cycles in wet oxygen, dry oxygen, and nitrogen ambients. The results indicate that ambients have an effect on the growth of bulk defects and denuded zone formation in the epitaxial silicon wafers.

Pyrolysis of a lignite in an entrained flow reactor: 3. Pyrolysis in reactive atmospheres of air, carbon dioxide and wet nitrogen

The role of the exchangeable cations on pyrolysis in the potentially reactive atmospheres of air, carbon dioxide and wet nitrogen has been studied in an entrained flow reactor. The amount and type of exchangeable cation present has been found to influence the behaviour of coal. In air, it was found that the presence of metal cations results in a decrease in initial weight loss in the reactor. At 0.05 s, weight loss in air at 1173 K was 30% when the metal cations were present and 80% when the cations were removed. While there was a dramatic effect of metal cations on initial weight loss, very little effect on weight loss at maximum residence time (0.25 s) was observed. Pyrolysis of the lignite samples in wet nitrogen and carbon dioxide led to a number of interesting results. Weight loss at maximum residence time for the acid washed lignite (metal cations removed) was virtually the same in nitrogen, carbon dioxide and wet nitrogen. Secondly, the raw lignite lost less weight than the acid washed lignite in all atmospheres, but the presence of carbon dioxide and wet nitrogen resulted in an increase in weight loss over nitrogen. Results are discussed in terms of the effect of metal cations on coal pyrolysis, char gasification and the interaction between the two.

Absorption of nitrogen monoxide in aqueous solutions containing sulfite and transition-metal chelates such as Fe (II)-EDTA, Fe (II)-NTA, Co (II)-Trien and Co (II)-Treten

For wet denitrification processes nitrogen monoxide is the crucial component owing to its low water solubility. By addition of transition-metal complexes, able to form nitrosyls, the effective NO concentration in the liquid phase is enhanced. Kinetic (reaction orders and rate constants) as well as thermodynamic (stability constants) data for nitrosylation have been established. It has been found that Fe(II)-EDTA and Fe(II)-NTA react very fast to form stable NO complexes and are widely pH independent. The formation of Fe(III)-EDTA nitrosyl is found to be rapid, but the large deviation in the measured data prevents reliable evaluation. While the equilibrium constants of the Co(II)-trien and Co(II)-tetren nitrosyls are largely pH independent, the rate of formation is influenced markedly by pH. Each nitrosyl shows individual behavior towards sulfite. Fe(II)-EDTA and Fe(III)-EDTA exhibit the highest absorption capacities. The CO(II) polyamines convert the absorbed NO mainly to gaseous N 2O rather than to liquid-phase products.

Changes in proteins from yolk and in the activity of benzoyl-L-tyrosine ethyl ester hydrolase from the yolk sac membrane during embryonic development of the chicken.

The wet weight and nitrogen content in the water soluble fraction and granule fraction of chicken egg yolk changed during embryonic development. Rapid decreases between Days 14 and 16 were the largest changes observed. When protein components in the soluble and granule fractions of yolk from developing eggs were analyzed by polyacrylamide gel electrophoresis under denaturing conditions, the intensities of bands of some high molecular-weight proteins decreased during incubation, while smaller proteins increased. Most of such changes were observed after Day 16. The activities of proteinases and hydrolases assayed with protein substrates or synthetic substrates at a neutral pH were higher in the yolk sac membrane than in yolk itself. A benzoyl-L-tyrosine ethyl ester hydrolase showed the highest specific activity among the enzymes examined in yolk sac membrane homogenates. Its activity increased after Day 5 of embryogenesis, and became maximum on Days 14 to 20. The data suggest that some of the yolk proteins are degraded by yolk sac membrane enzymes during the latter half of the incubation period.

Ruminal Nitrogen Degradability and Escape of Wet and Dry Distillers Grains and Wet and Dry Corn Gluten Feeds

Solubility and rate and extent of ruminal digestion of nitrogen in wet distillers grains, dry distillers grains, wet corn gluten feed, and dry corn gluten feed were evaluated in the laboratory, in situ, and in vivo. Distillers grains protein was the most insoluble in modified Burrough's mineral mix, corn gluten feed protein the least insoluble, and soybean meal protein intermediate. In the in situ trial (trial 1), nitrogen of wet and dry distillers grains and nitrogen of wet and dry corn gluten feed disappeared at similar rates, respectively. However, nitrogen disappearance rates were greater for wet and dry distillers grains. In the rumen escape trial (trial 2), wet distillers grains, dry distillers grains, wet corn gluten feed, and dry corn gluten feed were fed as supplemental protein sources and a urea control served to estimate endogenous nitrogen flow. Non-ammonia-nonbacterial nitrogen reaching the duodenum was lowest for steers fed the urea treatment (20.9 g/day). Rates were higher for wet distillers grains (64.1 g/day) and dried distillers grains (74.7 g/day) treatments compared to wet corn gluten feed (41.3 g/day) and dry corn gluten feed (32.7 g/day) treatments. Percentage protein apparently escaping rumen fermentation was greater for steers fed wet distillers grains (47%) or dried distillers grains (54%) than for those fed wet corn gluten feed (26%) or dry corn gluten feed (14%).

GROWTH OF THE FETAL GUINEA PIG: PHYSICAL AND CHEMICAL CHARACTERISTICS

Achievement of the intrauterine growth rate is a goal frequently used in nutrition of preterm infants. Data on the chemical composition of the human are limited and there is curiously little similar data in experimental animals. We studied physical and chemical macronutrient accretion in the fetal guinea pig, a species in which the high fat content and rapid growth rate emphasize the demands of fetal growth upon maternal nutrition. We studied 32 fetuses in 12 litters ranging from 39 days to term (67 d), analyzing the fetuses for wet weight, dry weight, carbon, nitrogen, fat content, caloric content (bomb calorimeter) and amino acid composition. Body weight increased exponentially with gestational age at 7.1%/d. Dry weight concentration tripled from 10% to 30% by term and total dry weight increased at 10.1%/d. Fat concentration rose from 2% at 45 days to 12% at term and fat content increased 13.5%/d. The total caloric accretion rate was 100 kcal/kg/d at 45 days, increasing to 220 kcal/kg/d at term. Over 60% of the caloric accretion was due to fat accretion. Caloric values of fat and non-fat dry weight were 9.5 and 4.5 kcal/g respectively. Amino acids represented 80% of the total body nitrogen and 46% of the total body carbon. These data represent the first systematic study of chemical growth during fetal life in any experimental animal, provide accretion measurements unavailable in human studies and demonstrate the importance of fat accretion in caloric demands of fetal growth.

Novel synthesis technique for zinc-silicate phosphors

A novel but simple synthesis technique for producing improved zinc-silicate phosphors with improved efficiency and persistence control as well as tight and uniform particle-size distribution is described. Silicic acid powder with a predetermined range of particle sizes is first coated with a solution containing manganese and arsenic ions and very fine zinc-oxide powder (100 A) and then fired in a wet nitrogen furnace at 1180°+/-50 C for 15+/-5 minutes. This method eliminates grinding and produces P1- and P39-type phosphors with cathodoluminescence performance superior to commercial samples.

Antifibrogenic effects of antiserum against the macrophage RNase.

Antiserum against the fibrogenesis controlling macrophage RNase was produced in rabbits. It caused an inhibition of 57% in the RNase activity in vitro. A distinct dose-response relationship was observed in the inhibiting effect of the antiserum on RNase-induced 3H-thymidine incorporation into cultured granulation-tissue fibroblasts. The antifibrogenic properties of the antiserum were also tested in vivo. Rat lungs were made silicotic by intratracheal administration of SiO2. This treatment clearly increased the following parameters: wet weight, DNA, RNA, nitrogen and hydroxyproline content of the lung tissue, and protein concentration, RNase activity, and cell count of the lung lavage fluid. Also, the RNase activity of the lavage fluid cells was increased. Periodical intratracheal administration of the anti-RNase antiserum, optimally at 1:1,000 dilution, decreased the DNA, RNA, and hydroxyproline content of the lung tissue, each by about 30%. The RNase activity of lavage fluid cells was decreased by about 60%. In conclusion the antiserum had no effect on the normal lungs, but it significantly suppressed the development of silicosis.

Effects of preservation on wet weight, dry weight, nitrogen and carbon contents of Calanus helgolandicus (Crustacea: Copepoda)

Effects of preservation on wet weight, dry weight, nitrogen and carbon contents of Calanus helgolandicus (Crustacea: Copepoda)

Effects of preservation on wet weight, dry weight, nitrogen and carbon contents of Calanus helgolandicus (Crustacea: Copepoda)

The lengths, wet and dry weights, nitrogen and carbon contents of fresh, frozen and formaldehyde-fixed specimens of Calanus helgolandicus (Claus) were determined. Samples were collected during May 1980 in the Celtic Sea. Individual Copepodite Stages 3, 4, 5, and Adult Male and Female Stage 6 were measured and analysed, and 36 linear regression equations derived for these variables together with mean values, standard deviations and 95% confidence limits. The range of nitrogen values in the fresh material, expressed as a percentage of dry weight, ranged from 8.08%±0.80 (Copepodite Stage 3) to 10.89%±0.27 (adult female); carbon values changed from 41.6%±3.05 (mean ±95% confidence limits) for Copepodite Stage 3 to 50.97%±2.63 in Copepodite Stage 5. The adult females had a high nitrogen and relatively low carbon content, while the converse was true for Stage 5 copepodites. There was a loss of dry weight from the frozen samples (57%) and the fixed samples (38%) compared with the mean of the fresh dry weight of all stages. The material lost from the copepods was rich in nitrogen, thus, artificially high percentage carbon values were determined from the frozen and fixed samples (52.0 to 60.3% and 44.7 to 58.5%, respectively).

Einflu� �berkritischen Kohlendioxids auf Proteine

Commercial ribonuclease was treated with wet supercritical carbon dioxide at 300 bars at room temperature and at 80°C. Amino acid composition and trinitrobenzene sulfonic acid-reactive lysine content were unaltered by this treatment. Disc electrophoresis with sodium dodecyl sulfate demonstrates a slight oligomerisation. This is mainly due to intermolecular linkages by disulfide bridges as indicated by disc electrophoresis after reduction with 2-mercaptoethanol. At the same time this technique indicates the cleavage of some peptide bonds within the disulfide loops of the ribonuclease molecule. Ribonuclease exposed to wet nitrogen under the same conditions shows the same alterations. They are obviously unrelated to the kind of gas used. The observed fragmentation is related to the presence of water. As indicated by tryptic digest these alterations do not decrease the digestibility by proteolytic enzymes. On the contrary the treated samples are split better than untreated ribonuclease. This is undoubtedly due to an unfolding of the protein molecule. The extent of this unfolding is definitely influenced by the presence of water. Ribonuclease samples treated with wet supercritical carbon dioxide only exhibit alterations that can be observed after heating at 80°C with water at normal pressure. In particular no chemical reactions with carbon dioxide can be demonstrated. Pressure in the range used here at best influences the alterations observed to a minor degree.

Succession of benthic community on artificial substratum at Elat (Red Sea)

The development of the benthic community on an artificial substratum in the Gulf of Elat was studied. The artificial substratum exposed for settlement of marine organisms was smooth polyethylene. Every month four test panels were removed and preserved. The animals removed from these panels were sorted and identified, mostly to the specific level. The number of individuals, the wet weight, and the nitrogen content were determined. The community eventually consisted of representatives of ten phyla and about 97 species, as follows: Mollusca, 34 species; Annelida, 23; Bryozoa, 11; Arthropoda, 10; Porifera, 7; Tunicata, 5; Coelenterata. 4; Nemertini, 1 or 2; Nematoda, 1 or 2; and Platyhelminthes, 1. The annelids were the dominant group as measured by the number of specimens, while the crustaceans, molluscs, and bryozoans were the most abundant groups as measured by wet weight and nitrogen content. It was found that 10% of the abundant species made up about 70% of the biomass, 20% made up 90–95%, and 30% made up 99%. Species diversity was calculated by Brillouin's formula, and was found to fluctuate widely from 0.45 to 2.03. The rate evenness ( H H max ) was relatively low (0.09–0.25) for most of the period, which is indicative of a homogenous community. The rate of change in the structure of the communities was found to be relatively high from one month to the next during most of the period, which indicates a high rate of turnover in the various species and their relative abundance. During the year the number of species in the monthly samples increased from 25 to 57.