Nitrogen Partition Research Articles

Nitrogenous disinfection byproducts formation and nitrogen origin exploration during chloramination of nitrogenous organic compounds

Formation of nitrogenous disinfection by-products (N-DBPs) of cyanogen chloride (CNCl), dichloroacetonitrile (DCAN) and chloropicrin was evaluated during chloramination of several selected groups of nitrogenous organic (organic-N) compounds, including α-amino acids, amines, dipeptides, purines, and pyrimidines, The intermediates generated, reaction pathways, and nitrogen origin in N-DBPs were explored as well. CNCl was observed in chloramination of all tested organic-N compounds, with glycine giving the highest yields. DCAN was formed during chloramination of glutamic acid, cytosine, cysteine, and tryptophan. Chloramination of most organic-N compounds except for cysteine and glutamic acid generated chloropicrin. Aldehydes and nitriles were identified as the intermediates by negative mode electrospray ionization mass spectrometry during reactions of NH 2Cl and organic-N compounds. Labeled 15N-monochloramine ( 15NH 2Cl) techniques showed that nitrogen in N-DBPs may originate from both NH 2Cl and organic-N compounds and the nitrogen partition percentages vary as functions of reactants and pH.

Utilization and Partition of Dietary Nitrogen in Dairy Cows Fed Grass Silage-Based Diets

Data from 207 production trials (998 treatment means) were used to study the effects of animal and dietary characteristics on the efficiency of N utilization for milk protein production, and on fecal N, urinary N, and total manure N output. The average efficiency of transferring dietary N to milk N (MNE; milk N/N intake) was 277 (SD=36.0) g/kg. Nitrogen efficiency was poorly related to milk yield. Dietary concentrations of crude protein (CP) and protein balance in the rumen (PBV) were the best single predictors of MNE. Dietary CP concentration explained variation in MNE better than did N intake. Bivariate models with PBV or metabolizable protein (MP) explained the variation better than CP alone. The effects of protein feeding parameters on MNE were consistent among data subsets from studies investigating the effects of the amount and protein concentration of concentrate supplement, silage digestibility, silage fermentation quality, or substitution of grass silage with legume silage. The model with total dry matter and N intakes as independent variables explained fecal, urinary, and total manure N output more precisely than N intake alone. The model of fecal N output suggested that the true digestibility of dietary N was 0.91, and that metabolic and endogenous N was the major component in fecal N. The proportion of urine N in manure N was strongly related to dietary CP concentration. Including the concentration of dietary carbohydrates only slightly improved the models, indicating that the most effective strategy to improve MNE and to decrease N losses in manure, especially in urine, is to avoid feeding diets with excessively high CP concentration and especially excess ruminally degradable CP.

Nitrogen accumulation, partition, and nitrogen-use efficiency in canola under different nitrogen availabilities

Nitrogen (N) accumulation and its partition in a canola (Brassica napus L. ssp. oleifera var. annua) crop growing under different N availabilities were evaluated. Spring canola (cultivar Printol) plants were grown with 0, 30, 60, 90, 120, or 150 kg N ha− 1 applied at sowing. They were harvested at D1 (flower buds covered by leaves), G1 (first flowers fall), and G5 (maturity) phenological stages and separated into stems, leaves, inflorescences, reproductive structures, and seeds according to its development stage. Dry matter and N concentration of each fraction were evaluated. At maturity, seed yield, harvest index and N use efficiencies were evaluated. Nitrogen concentration in the whole plant and its different organs increased with the increase of N applied in the three stages analyzed. The greatest N accumulation (14.44 g m− 2 for 150 kg N ha− 1) was registered at G1 and then it decreased 11% toward maturity. Nitrogen accumulated in seed increased from 2.83 g m− 2 to 7.66 g m− 2 (170% over the control) with application of 150 kg N ha− 1. The highest N harvest index was observed with 30 kg N ha− 1 applying. The apparent N recovery in plant averaged 57% at G1 and it was not modified by N applications. In contrast, N utilization efficiency declined with the N rate increase. The results show that N application at sowing time increases total N accumulated by canola but has little effect on N partition among plant parts even at high rates. Also, it is confirmed the important response of this crop to fertilization but the decrease in its N use efficiency with the increase of N rate. The low average values of apparent N recovery found in this experiment point out the need of adjust fertilizer-applying practices in order to improve N recovery possibilities of the crop.

Evaluation of Fish Silage-Sweet Potato Mixed Diet with Italian Ryegrass Silage as Basal Ration on Nitrogen Utilization and Energy Balance in Growing Lambs

This study investigated the feed intake, and energy and nitrogen partition of growing lambs fed on diet with fish silage (FS) as a major protein supplement. The FS was compared with the conventional protein feeds like fish meal (FM) and urea (UR). Six castrated and 6 female Suffolk lambs were divided into three groups and fed on Italian ryegrass silage (IRS) as basal ration at 70% on dry matter (DM) basis. The protein based concentrate mixture of FS, FM or UR was supplemented to one of the three groups at 30% DM. The DM intake of animals was not affected by FS diet and was comparable with the other diets. Likewise, the organic matter intake and digestible organic matter intake (DOMI) of the animals were unaffected by the varying protein supplements. The nitrogen retention of FS group was 37% higher than that of the UR group, however, the FM group was significantly higher than the UR group (P〈0.05). The retained energy of FS group with 116.6kJ/kg W0.75/d tended to decline compared to the other groups. The methane energy and methane production of the FS group which were 79.1kJ/kgW0.75/d and 55.6 L/kg DOMI, respectively, had a lower tendency while the heat production with 13.2MJ/kg DOMI tended to increase compared to the other treatments. The respiratory quotient of the FS group with 1.09 tended to be lower than the other groups. These results suggest the potential of fish silage as a major protein supplement but further investigation is needed to upgrade the palatability and nutritional value.

Characterization of the dromedary milk casein micelle and study of its changes during acidification

Biochemical and physical properties of dromedary milk were studied at initial pH and during an acidification with glucono-δ-lactone. In comparison with bovine milk salt, citrate and nitrogen partition between soluble and micellar phases revealed several characteristics. Dromedary milk micelle presented a more important mineral plus citrate charge (~ 98 mg .g -1 casein). Micellar Mg, P and citrate proportions were higher, about 2/3, 2/3 and 1/3, respectively. During acidification, micellar mineral and citrate release started tardily (~ pH 5.8) and the maximum of casein and Pi solubilization took place at lower pH values, 4.9 and 4.8, respectively. Dromedary milk micelle see- med to maintain its integrity until about pH 5.5, below, it underwent extensive biochemical and structural modifications mainly at pH 5.0. At this point, dromedary milk was characterized by a loose microstructure, by a maximum of loss modulus and of micelle hydration and by a minimum of apparent viscosity. The pH 5.0 would be a transition pH between micellar structure and coagulum struc- ture.

Approaches to modelling heterogeneous char NO formation/destruction during Pulverised coal combustion

Emissions of nitrogen oxides during combustion pose a major environmental problem and hence there is considerable interest in reducing the NOx levels encountered during pulverised coal combustion. The chemically bound nitrogen in the fuel is known to account for up to 80% of total NOx. Whilst the homogeneous production pathways of NOx from the nitrogen present in the coal volatiles are relatively well known, the heterogeneous conversion of the nitrogen retained in the char to NO is less well understood. As part of an ongoing project to develop an advanced coal model to describe the combustion process in pulverised coal flames this study examines the possible mechanisms involved in both nitric oxide formation and reduction at the char surface for a more accurate prediction of char–NO interactions. The use of a model to predict the partition of coal nitrogen between volatiles and char has also been explored. Various mechanisms of NOx production/destruction at the char surface are discussed and it is concluded that the best approach for computational modelling is to treat the formation and reduction pathways separately. The rate of NO formation is related to that of the char oxidation by the molar ratio of carbon to nitrogen in the char. The rate of NO reduction at the char surface is represented by RNO=2.6·104exp−15 900TAEPNO mol s−1, where AE is the external area of the char (m2 g−1) and PNO is the partial pressure of NO (atm).

5616289 Substance and/or heat exchanging tower

Using stable isotope data obtained on multiple aliquots of diamonds from worldwide sources, it has been argued that carbon and nitrogen in diamond are decoupled. Here we re-investigate the carbon–nitrogen relationship based on the most comprehensive microbeam data set to date of stable isotopes and nitrogen concentrations in diamonds (n = 94) from a single locality. Our diamond samples, derived from two kimberlites in the Chidliak Field (NE Canada), show large variability in δ13C (− 28.4 ‰ to − 1.1‰, mode at − 5.8‰), δ15N (− 5.8 to + 18.8‰, mode at − 3.0‰) and nitrogen contents ([N]; 3800 to less than 1 at.ppm). In combination, cathodoluminescence imaging and microbeam analyses reveal that the diamonds grew from multiple fluid pulses, with at least one major hiatus documented in some samples that was associated with a resorption event and an abrupt change from low δ13C and [N] to mantle-like δ13C and high [N]. Overall, δ13C appears to be uncorrelated to δ15N and [N] on both the inter- and intra-diamond levels. Co-variations of δ15N–log[N], however, result in at least two parallel, negatively correlated linear arrays, which are also present on the level of the individual diamonds falling on these two trends. These arrays emerge from the two principal data clusters, are characterized by slightly negative and slightly positive δ15N (about − 3 and + 2‰, respectively) and variable but overall high [N].Using published values for the diamond-fluid nitrogen isotope fractionation factor and nitrogen partition coefficient, these trends are perfectly reproduced by a Rayleigh fractionation model.Overall, three key elements are identified in the formation of the diamond suite studied: (1.) a low δ13C and low [N] component that possibly is directly associated with an eclogitic diamond substrate or introduced during an early stage fluid event. (2.) Repeated influx of a variably nitrogen-rich mantle fluid (mildly negative δ13C and δ15N). (3.) In waning stages of influx, availability of the mantle-type fluid at the site of diamond growth became limited, leading to Rayleigh fractionation. These fractionation trends are clearly depicted by δ15N–[N] but are not detected when examining co-variation diagrams involving δ13C. Also on the level of individual diamonds, large (≥ 5‰) variations in δ15N are associated with δ13C values that typically are constant within analytical uncertainty. The much smaller isotope fractionation factor for carbon (considering carbonate- or methane-rich fluids as possible carbon sources) compared to nitrogen leads to an approximately one order of magnitude lower sensitivity of δ13C values to Rayleigh fractionation processes (i.e. during fractionation, a 1‰ change in δ13C is associated with a 10‰ change in δ15N). As a consequence, even minor heterogeneity in the primary isotopic composition of diamond forming carbon (e.g., due to addition of minor subducted carbon) will completely blur any possible co-variations with δ15N or [N]. We suggest this strong difference in isotope effects for C and N to be the likely cause of observations of an apparently decoupled behaviour of carbon and nitrogen isotopes in diamond.

Behaviour of nitrogen during liquefaction of dewatered sewage sludge

The behaviour of nitrogen compounds during the liquefaction of dewatered sewage sludge was examined. After liquefaction (at 150–350°C), the product mixture was separated into oil A (water-soluble), oil B (water-insoluble), aqueous phase and solid residue. Partition of nitrogen to oil occurred at > 150°C. Above 150°C, 60% of the nitrogen in the sewage sludge was transferred to the aqueous phase. Solubilization and decomposition of the nitrogen compounds were promoted at 150°C. The distribution of nitrogen to oil B obtained by liquefaction at 300°C was 9%, whereas that to oil A was 11%.

A general model for partitioning of gases between a metal and its plasma environment

When a metal or an alloy is exposed to a pure diatomic gas such as nitrogen, the concentration of the species in the material can be predicted from Sieverts law. However, such calculations cannot be used to understand processes in which the gas phase near the metal contains excited molecules, atoms, ions, and electrons, in addition to the diatomic gases. The presence of plasma leads to species concentrations in the metal that are much higher than the values predicted by the Sieverts law. At present, there is no unified theoretical model to understand the partition of nitrogen, oxygen, and hydrogen between a metal and its plasma environment. In this work, a theoretical model has been developed to understand the enhanced solubility of gases in metals exposed to plasma environment. The model has been applied to explain several different sets of independent experimental results available in the literature. The analysis of the data shows that the enhanced solubilities can be explained on the basis of superequilibrium concentration of atomic species near the metal surface. Both the enhanced solubilities and the maximum species concentrations predicted by the model are in good agreement with the independent experimental data for various systems.

Effect of Level and Degradability of Rapeseed Meal in Rations for Dairy Cows: 2. Diet Digestibility, Dietary Nitrogen Partition and Urinary Purine Derivatives Excretion

Abstract The effects of level and degradability of rapeseed meal on ration digestibility, N balance, urinary purine derivatives excretion, milk production and milk composition in dairy cows were studied. A total of 24 multiparous lactating diary cows were selected from a production experiment and divided into two 12-cow groups according to their lactation stage (LG1, 14th-16th week of lactation; and LG2, 26th-30th week of lactation). Within lactation groups, cows were fed four different rations (3 cows per treatment). Four concentrate mixtures with two levels of protein (19% and 14% of CP on DM basis) and two different rumen degradabilities (72% and 52%) of the dominating protein feed rapeseed meal were fed to the cows together with pasture silage and hay. Apparent total tract digestibilities were not affected by the treatments. N balance was positive and similar between diets in both lactation groups. N partition data were similar between treatments on LG1, while on LG2 a tendency for a more efficient us...

Nitrogen partition in cell structures of tropical browse plants compared with temperate forages: influence on their in situ degradation pattern

The N ruminal degradation of tropical browse plants was compared with that of forages harvested in temperate regions, and the relationships between in situ N degradability and detergent fibre N content examined. Six browse plants were collected during the hot dry season in the semi-arid zone of West Africa (Senegal). Six hays were prepared from forages grown at Clermont-Ferrand, a semi-mountainous area in a temperate zone. We measured the partition of nitrogen (N) in feedstuffs with the detergent fibre system and the N and fibre N ruminal degradation with the nylon bag technique. Nitrogen in the neutral detergent fibre (expressed as percent total N) varied from 10 to 64% for browses and from 23 to 48% for hays. For browses, an important part of the cell wall N was located in the acid detergent fibre (ADFN). As a consequence of these chemical composition variations, there were large differences in N degradability of the browses, from 28% (leaves of Guiera senegalensis) to 86% (pods of Acacia raddiana). It was closely related to ADFN contents (RMSE = 3.6; R 2 = 0.98). The extent of N degradability variations was much lower for hays, from 70 to 79%.

The partition and utilisation of energy and nitrogen by sows during their first lactation

If dietary intake is insufficient to meet the metabolic needs of the sow during lactation then maternal body reserves (body fat and body lean) are mobilised to support milk production. However the extent to which body reserves are mobilised may influence the metabolic and physiological state of the sow and hence reproductive function after weaning (Mullan and Close, 1989). There is little available information on the metabolic response of the lactating sow and the present experiment was designed to study the partition and utilisation of energy and nitrogen (N) intake in sows during their first lactation. This should aid in the understanding of how the dynamics of nutrient utilisation during lactation may influence the metabolic and reproductive state of the sow.The experiment was designed in a 2 X 2 factorial arrangement (5 animals per treatment) with 2 levels of feed (H, 5.5 kg/d and L, 3.0 kg/d) during lactation and with 2 litter sizes at each feeding level (6 or 12). Sows were accommodated throughout the 21-day lactation in farrowing crates adapted to permit the total collection of sow and piglet excreta.

Effect of Somatotropin on Kinetics of Nonesterified Fatty Acids and Partition of Energy, Carbon, and Nitrogen in Lactating Dairy Cows1,2

The utilization of energy, carbon, and nitrogen, and irreversible loss rates of nonesterified fatty acids were examined in lactating cows during treatment with bovine somatotropin. Six multiparous Holstein cows at approximately 62 d postpartum received daily intramuscular injections of somatotropin (29.4 mg/d) or excipient during two 21-d treatment periods in a crossover experimental design. Milk yield was increased 11% (37.1 versus 41.3 kg/d), whereas intake and digestibility of DM, energy, nitrogen, and carbon were not affected. Cows remained near zero net energy balance during both treatments (1.31 versus −1.52 Mcal/d for control and somatotropin, respectively). The major effect of somatotropin was to partition net energy into milk while tissue energy accretion was reduced. Postabsorptive use of nitrogen and carbon was altered by somatotropin as reflected by greater secretion in milk. Urinary losses of nitrogen and tissue use of carbon were reduced. Plasma concentrations and irreversible loss rates of nonesterified fatty acids did not differ between treatments. Somatotropin treatment of lactating cows results in partitioning of nutrients away from tissue deposition toward milk synthesis. The extent to which different metabolic processes are altered depends upon the energy balance of the somatotropin-treated animal.

Effects of different rhizosphere sizes on the growth, distribution patterns and utilization of nitrogen fertilizers of different varieties of rice plants (Oryza sativa L.) on the same hill.

In order to clarify the inter-hill competition at the maturing stage. Using the tracer 15N method. The growth characteristics of rice plants (Oryza Sativa L., cv. Suweon no. 258 and TKM-6) grown in pots of different sizes were examined. The top dry weights of two varieties, TKM and Suweon planted on the same hill were 82.84% and 16-18%, respectively. In Suweon, the ratio of culm dry weight did not change with rhizosphere size, but the ratio of leaf blade dry weight to the total weight increased with decreasing rhizosphere size; whereas the ratio of the dying organ dry weight showed an opposite behaviour. The percentage of nitrogen content increased with increasing rhizosphere sizes in two varieties, with a greater increase in Suweon. The percentage of nitrogen contents in TKM was higher than that in Suweon in smaller rhizospheres, but in larger rhizospheres Suweon showed a higher percentage of nitrogen than in TKM. The ratio of recovery of 15N top-dressing in basal-dressing plot was 51-79%, at the panicle formation stage plot, 51-59%, and at the reduction division stage plot, 63-78%. Further-more, lager pots and later nitrogen supply showed a high nitrogen content. The ratios of 15N content in the two varieties in basal-dressing plot were 74-84%, and top-dressing at the tillering stage save 76-83%. With TKM top-dressing at the reduction division stage, they were 80-85%, a very high rate of recovery of nitrogen. Partition of 15N content of ears in each top-dressig time in the basal-dressing plot was 37-62%, the tillering stage 53-71%, at the panicle formation stage 63-67%, and at the reduction division stage 54-67%. These results revealed that smaller rhizospheres led to a cleary high partition of nitrogen.

An approach to the determination of rumen degradability of nitrogen in low-grade roughages and partition of nitrogen therein

SummaryRumen degradability of dry matter (D.M.) and N in wheat straw, rice straw and local grass hay, containing 5·16, 6·37 and 4·58 mg N/g D.M. respectively, was estimated by rumen fermentation measurements at 3, 6, 9, 12, 24 and 48 h using the nylon bag technique. The degradability of D.M. at an assumed rumen outflow rate of 0·025/h was 21·7, 34·9 and 22·4 for wheat straw, rice straw and grass hay, respectively. Theestimation of degradability of N was confounded by thedeposition of ruminal microbial nitrogen in the nylon bag. A correction was made by measuring the accumulation of N when N·free fibre and cellulose were incubated in the nylon bags. The effective degradability of N in the roughages at the assumed rumen outflow rate was 54·5, 36·9 and 42·8% respectively, showing that the roughages contain rumen-degradable N for microbial nutrition. The undegradable nitrogen (UDN) values in wheat straw, rice straw and grass hay were 2·35, 4·02 and 2·62 mg/g D.M., and after correction for unavailable acid detergent-linked N, the available UDN values were 0·58, 2·95 and 1·32 mg/g D.M., respectively.

Thermodynamics of nitrogen in CaO-SiO2-AI2O3 slags and its reaction with Fe-Csat. melts

The solubility of nitrogen as the nitride ion in CaO-SiO2-Al2O3 slags in equilibrium with N2-CO gas mixtures and carbon was measured at 1823 K. The nitride capacity (C N3-) was calculated to compare the nitrogen contents measured under different nitrogen and oxygen potentials.C N3- decreased with increasing basicity and by replacing SiO2 with A12O3. The nitrogen partition ratio between carbon saturated iron and the slag was measured in CO gas at one atmosphere at 1823 K. By comparing the partition ratios with the corresponding nitride capacities measured by the gas-slag experiments, it was concluded that the oxygen partial pressure at the slag-metal interface was controlled by the Fe-FeO reaction. A new definition of nitride capacity was proposed based on the reaction between nitrogen and the network former,i.e., SiO2 or A12O3. This capacity could consistently explain the experimental results. Empirical equations were derived to estimate the activity coefficients of silicon and aluminum nitrides in the slags.

Effects of Variety and Particle Size upon Utilization of Fescue Hay by Lactating Dairy Cows and Dairy Heifers

Missouri-96 and Kentucky-31 hays were chopped with a tub grinder containing screens with apertures of 31, 63, or 100mm in diameter and fed to dairy cows or heifers. Particle sizes (geometric mean diameter) were 1218, 1486, and 1933 μm, respectively, for the 31, 63, and 100-mm treatments. In Trial 1, the six treatments were fed ad libitum to 24 lactating cows; concentrate was offered at 1 kg/2kg of milk. Dry matter intake and NDF digestibility were greater for Kentucky-31, but there were no other effects of variety. Particle size did not affect DM intake, DM or fiber digestibility, nitrogen partition, milk yield, or milk fat percentage. Crude protein digestibility was greatest for the 63-mm particle size treatment.In trial 2, the six treatments were fed ad libitum to 24 dairy heifers. Intake was greater for the 31 than for the 100-mm treatment but was unaffected by variety. Variety and particle size did not affect DM digestibility, nitrogen utilization, or daily gain. In this study fescue hay chopped through screens having apertures ranging from 31 to 100mm was without effect on milk yield or composition. Reducing particle size increased intake and nitrogen utilization but not DM or fiber digestibility.

Partition of nitrogen in solidifying iron-carbon-silicon alloys

The partition of nitrogen between austenite and liquid iron was examined from the measurement of solubilities of nitrogen in these phases. On primary austenite crystallization, nitrogen was rejected into liquid iron at high temperatures and the partition behaviour was reversed at low temperatures. Silicon lowered the critical temperature where the partition behaviour of nitrogen changed. The partition of nitrogen between cementite and austenite was investigated by analysis of nitrogen in iron-carbon-silicon alloys, which were quenched in ice-water from an equilibrium state at subeutectic temperatures, and in the cementite extracted from them. Nitrogen was enriched in cementite for Fe-C-0.5 wt% Si alloy, similar to the case of pure Fe-C alloy. However, silicon reduced the degree of enrichment of nitrogen in cementite. By the use of the partition coefficients, the variations of nitrogen concentrations in the coexisting phases were evaluated during the solidification of cast irons. In the irons with lower carbon concentrations, the supersaturation of nitrogen in liquid iron attained during solidification increased with increasing silicon content, and silicon had a detrimental effect to promote the formation of nitrogen gas blowholes in low-carbon cast irons.

Ecology of Tropical Savannas.

The Ecological Studies series presents a symposium and workshop convened by the South African savanna ecosystem project. The 28 papers are divided into six sections: structure, determinants, function, dynamics and management. The contributing scientists were mostly from South Africa itself, with others from other African nations, Australia, Brazil, Venezuela, Israel and Europe. The opening section is mostly descriptive of savanna vegetation in several parts of the world, and is followed by papers on obvious ecological linkages, such as soils, soil nutrients and fire. Modern work on ecosystem metabolism considers processes such as water relations, herbivory, and nitrogen partition and near the end, dynamics and management are dealt with, mainly in the context of the concepts of stability and resilience.

Predicting Maternal Protein and Fat Balances of Growing and Mature Dry Cows

To examine factors affecting maternal protein and fat changes of dry cows, we fed a diet of silages at varying intakes. Conceptus-corrected balances (fat and protein) were computed and predicted from ration protein and energy densities (digestible, metabolizable, or total digestible nutrients), predry body weight, dry matter intake as percents of body weight or predry body weight, and square or natural log of each. Maximum daily dry matter intake was 1.8% of body weight. Observed energy density did not change with changing intake. Proportion of ingested energy apparently stored increased with dry matter intake/predry body weight, primarily at the expense of heat production. Partition of energy and nitrogen were not significantly affected by this intake expression. Cows in first and subsequent dry periods fed low intakes had positive maternal fat balances at energy intakes equal to or below established maintenance requirements. Body condition score of primiparous cows did not increase and their growth was related to dry matter intake, predry weight, total digestible nutrients, and protein percentage of the diet; daily maternal fat balance followed protein balance (2:1 ratio) up to energy intake 14% above maintenance, thereafter increasing to 4:1 ratio. In older cows, maternal daily fat balance varied primarily with digestible energy density of ration, intake, and to a lesser extent wth predry weight and ration protein; protein balance was not closely related to factors studied.