Various Concentrations Of Ammonia Research Articles

Improvement of ammonia sensing properties of poly(pyrrole)–poly (n-methylpyrrole) composite by ion irradiation

In the present investigation we have electrochemically synthesized polypyrrole–poly (n-methylpyrrole) composite film with optimized process parameters (viz. concentration of monomers and dopant, applied current density, deposition time, pH of electrolyte etc.) on platinum substrate. The composite film of polypyrrole–poly (n-methylpyrrole) was subjected to electrical, spectral and morphological characterizations and its sensing response to various concentration of ammonia was also studied. Later, the synthesized composite films were irradiated under high vacuum (∼5×10−6 Torr) at room temperature with 85 MeV O7+ ion beam at various fluences from 1×105 to 1×107 ions/cm2. We have observed remarkable improvements in electrical and morphological properties suitable for gas-sensing applications. The irradiated composite film was evaluated for the sensing of various concentrations of ammonia and excellent improvement in terms of sensitivity, lower detection limit and response time was observed.

Non-Imaging Optical Method for Multi-Sensing of Gases Based on Porous Silicon

We demonstrate an optical sensor for the detection of ammonia in gaseous phase under a changing humidity environment. The sensor is based on a sectioned nano-structured porous silicon (PSi) device in which the parts react distinctly to ammonia and water vapor. The distinct sensing is necessary since most ammonia indicators' sensitivities are highly dependent on the ambient relative humidity. The sensor is interrogated with a single white-light beam, and changes in the reflectivity sensor are monitored. The combined interference pattern from both PSi sections is observed and measured under various concentrations of ammonia and water vapor. The structure is designed to frequency encode the reflectivity spectrum and Fourier-transform data-analysis is applied in order to enable simple discrimination between different ammonia and water vapor concentrations. The method allows remote and distance-insensitive analysis of gases in breath and other gaseous environments.

Age‐related effects of varying ammonia concentrations on hematophysiological variables in broiler chickens,

This study examined the response of different aged birds of the same genetic strain exposed to ammonia at set concentrations on blood physiological variables under environmentally controlled conditions. The experiment consisted of 4 levels (0, 25, 50 and 75 ppm) of ammonia concentrations and 4 different ages (1‐day, 7‐days, 14‐days and 21‐days) arranged in a complete randomized factorial design. Venous blood samples were collected at the end of each 7 days of ammonia exposure. Partial pressure of CO2 (pCO2), pH, hematocrit (Hct), and hemoglobin (Hb) increased significantly (P = 0.05), whereas partial pressure of O2 (pO2), bicarbonate (HCO3−), and K+ decreased with increasing ammonia concentration compared with 0 ppm. In addition, pO2, pCO2, HCO3−, Hct, Hb, Na+, and anion gap (Angap) increased significantly (P = 0.05), while pH, glucose, and corticosterone decreased as bird's age increased. Ammonia × age interactions were observed for pH, anion gap, and HCO3−. There was significant main effect of age but not that of ammonia on plasma corticosterone concentrations. The main effect of age was more pronounced than that of ammonia on examined variables. These conditions improved as the age of birds increased from 1‐d to 21‐d old. It was concluded that different aged birds of the same genetic strain respond differently to set ammonia concentrations and younger birds have a more intense reaction to the ammonia than older birds.

Age-Related Effects of Varying Ammonia Concentrations on Hematophysiological Variables in Broiler Chickens

This study examined the response of different aged birds of the same genetic strain exposed to ammonia (NH ) at set concentrations on blood gases, electrolytes and acid-base balance under 3 environmentally controlled conditions. The experiment consisted of a 4×4 factorial with a randomized design. The 16 treatments consisted of 4 levels (0, 25, 50 and 75 ppm) of NH concentrations and 4 different ages 3 (1-d, 7-d, 14-d and 21-d) of birds. Venous blood samples were collected at the end of each 7 d of atmospheric NH exposure. Partial pressure of CO (pCO ), pH, Hematocrit (Hct) and Hemoglobin (Hb) 3 2 2 increased significantly (p<0.05), whereas partial pressure of O (pO ), bicarbonate (HCO ) and K decreased 2 2 3 - +

Investigations of the polyaniline and nafion bilayer sensor structure in SAW system

Presented here are the preliminary results concerning an investigations of a novel bilayer sensor structure of polyaniline and Nafion as a toxic gas sensors in a Surface Acoustic Wave system. The investigations were performed with different concentrations of the various toxic gases like SO 2 , CO, H 2 S and ammonia (NH 3 ) in synthetic dry air. The prototype polyaniline and nafion bilayer structure has been manufactured by two deposition technologies: 180 nm of PANI by PVD technology and thin Nafion film by spin coating technology and specific process of annealing. A good interaction with various concentrations of ammonia for the bilayer structure (PANI film with Nafion) has been observed.

Effects of ammonia during different stages of culture on development of in vitro produced bovine embryos.

The effects of various concentrations of ammonia in the media during in vitro fertilization (IVF), culture (IVC), and throughout maturation (IVM), IVF, and IVC were evaluated using a randomized complete block design. Ammonia was added to the media at various concentrations during IVF (experiment 1), during IVC (experiment 2), and throughout IVM, IVF, and IVC (experiment 3). In the first experiment, there was a significant (P<0.05) increase in embryos developed to blastocyst, and to expanding and hatching blastocyst, in IVF media containing moderate concentrations of ammonia compared with that in the IVF control media. In the second experiment, ammonia in the IVC media increased (P<0.05) the proportion of degenerate ova and decreased (P<0.05) the proportion of ova that developed to blastocysts. In experiment 3, cleavage rates tended (P=0.06) to be greater for control groups than for treatment groups. The proportion of ova developing to morula was greater (P<0.05) in media containing moderate concentrations of ammonia than that in the control groups. These results indicate that the effect of ammonia on development of preimplantation bovine embryos depends on the concentration of ammonia and the stage of development when exposure to ammonia occurs.

Effect of ammonia on the survival of Zacco platypus (Temminck and Schlegel) at each developmental stage

The survival rates were studied of fertilized eggs, larvae, fry, and adults of pale chub Zacco platypus (Temminck and Schlegel) exposed to various concentrations of ammonia. There was a decrease in hatching rate and an increase in deformed alevins at a concentration of 0.9 mg liter −1 of ammonia. All alevins were deformed at a concentration of 1.6 mg liter −1 of ammonia and no eggs hatched at a concentration of 3.1 mg liter −1 of ammonia. No larvae survived for 84, 24 and 12 h at concentrations of 1.2, 2.0 and 4.7 mg liter −1 of ammonia, respectively. Eighty percent of the fry died after 168 h and no fry survived for 24 h at concentrations of 1.6 and 2.1 mg liter −1 of ammonia, respectively. Eighty percent of the adults died after 24 h and no adult survived for 12 h at concentrations of 1.0 and 1.9 mg liter −1, respectively. Larger adults were the most susceptible to ammonia. The order of resistance to ammonia was eggs, fry, larvae, and adults.

On-line monitoring and modelling based process control of high rate nitrification ? lab scale experimental results

This paper presents a new concept for the control of nitrification in highly polluted waste waters. The approach is based on mathematical modelling. To determine the substrate degradation rates of the microorganisms involved, a mathematical model using gas measurement is used. A fuzzy-controller maximises the capacity utilisation efficiencies. The experiments carried out in a lab-scale reactor demonstrate that even with highly varying ammonia concentrations in the influent, the nitrogen concentrations in the effluent can be kept within legal limits.

Effects of ammonia on survival and osmoregulation of various development stages of the shrimp Penaeus japonicus

In Penaeus japonicus, the tolerance to ammonia increased with the development from nauplius to late juvenile. The 48-h LC50 of ammonia in nauplii (III–V), 96-h LC50 in zoeae (I–III), mysis (I–III), post-larvae (PL1) and late juveniles (10.4±1.1 g) were respectively 5.0, 6.1 to 8.1, 9.4 to 10.9, 15.5 and 52.7 mg Nl-1 (0.5, 0.6 to 0.7, 0.9, 1.3 and 3.1 mg NH3−Nl-1). In a chronic experiment (20 d), the LC50 in post-larvae (PL1) was 19.1 (1.4) at 96 h and 16.2 mg Nl-1 (1.3 mg NH3−Nl-1) at 480 h. Osmoregulatory capacity (OC) was calculated as the osmotic gradient between the hemolymph and the external medium at given salinities. The effects of ammonia on OC, Na+ and Cl- regulation and gill Na+−K+ ATPase activity in late juveniles were examined in fullstrength seawater, SW (1050 mosm kg-1, 36‰ S) and in dilute SW (450 mosm kg-1, 15%.), after 48 or 96 h exposure to various concentrations of ammonia. Ambient ammonia disrupted both hypo- and hyper-osmoregulation; decreased OC resulted from impaired Na+ and Cl- regulation. Gill Na+−K+ ATPase activity increased in SW and was not affected in dilute SW. The decrease of OC was ammonia-dose-dependent. The threshold ammonia concentrations affecting hypo-OC and hyper-OC were, respectively, 16 (1.3) and 32 mg Nl-1 (2.3 NH3−Nl-1) for a 48 h exposure; these concentrations were lower than the 48-h LC50 value, 65.3 mg Nl-1 (3.5 NH3−Nl-1). The time course of exposure to sublethal ammonia (48 mg Nl-1) demonstrated that the effect on osmoregulation was time-dependent. This effect was also temporary, and the exposed shrimps recovered control OC values after removal of excessive ambient ammonia. The possibility of using OC as an indicator of physiological condition in osmoregulating crustaceans and the acting mode of ammonia on osmotic and ionic regulation are discussed.

Effect of ammonia on the hydrogenation of naphthalene or butylbenzene during the hydrodenitrogenation of quinoline

The hydrogenation of naphthalene in the presence of various concentrations of ammonia was studied during the hydrodenitrogenation of quinoline on a sulfided NiMo/Al 2 O 3 catalyst at 360°C, 6.9 MPa total H 2 pressure, in a vapor-phase tubular reactor. The selectivity to tetralin instead of to decalins was increased by increased ammonia concentration. This observation may have relevance to coal liquefaction. Brief studies on the effect of ammonia on the hydrogenation of butylbenzene are reported

Toxicities of ammonia and nitrite to Penaeus monodon adolescents

Penaeus monodon adolescents (91.0±8.0 mm) were exposed to various concentrations of ammonia (NH 3+NH 4 +) and nitrite in 20 ppt seawater at a pH of 7.57 and a water temperature of 24.5°C using the static renewal method. The LC50 values of ammonia-N (un-ionized plus ionized ammonia as nitrogen), NH 3-N (un-ionized ammonia-N) and nitrite-N decreased with longer exposures. The 24-, 48-, 96- and 144-h LC50 values were 97.9, 88.0, 53.4 and 42.6 mg/l of ammonia-N (1.76, 1.59, 0.96 and 0.77 mg/l of NH 3-N), respectively. The 24-, 48-, 96-, 144-, 192- and 240-h LC50 values of nitrite-N were 218, 193, 171, 140, 128 and 106 mg/l nitrite-N, respectively. The “thresholds” of ammonia and nitrite toxicity were found at 144 and 240 h, respectively, on a toxicity curve approaching an asymptote. Based on the incipient LC50 value and an application factor of 0.1, safe values for rearing adolescent P. monodon (20 ppt, 7.57 pH, 24.5°C) were calculated to be 4.26 mg/l ammonia-N, 0.08 mg/l NH 3-N and 10.60 mg/l nitrite-N.

THE CHARACTERIZATION OF KINETICS BY SINGULAR POINTS: COMPARISON OF SUPPORTED VS. UNSUPPORTED AND ISOTHERMAL VS. NONISOTHERMAL Pt CATALYSTS IN AMMONIA OXIDATION

Similar multiplicity features were observed during ammonia oxidation on supported or unsupported Pt catalysts, whether in the isothermal or nonisothermal modes of operation. Two types of isothermal multiplicity patterns were observed upon varying ammonia concentration. The simplest model predicting the transition between the two must have a pitchfork singularity. The same singularity accounts also for the diagrams observed with varying oxygen concentration. The singularities of the isothermal kinetics are inferred also from nonisothermal experiments These similarities suggest that identical kinetic models are responsible for multiplicity in supported and unsupported catalysts. The dependences on either reactant is used to characterize the kinetics by defining the highest order singularity in the temperature-concentrations space. This information is utilized to develop the simplest rate expression which accounts for the observations The two simultaneous reactions, producing N2 and N2O, were found to ignite...

Effect of ammonia on viability and blastogenesis of bovine lymphocytes

The effect of addition of ammonia into the tissue culture on viability and functions of bovine lymphocytes was studied. The concentrations of ammonia in the tissue cultures represented toxic, subtoxic, and normal concentrations of ammonia in the bovine blood during clinical and subclinical urea toxicosis. Lymphocytes separated from peripheral bovine blood were incubated in control medium and test medium with various concentrations of ammonia and/or PHA or Con A. Viability of the lymphocytes was measured by trypan blue exclusion test and their mitogenic reactivity by incorporation of 3H thymidine into DNA of lymphocytes. Approximately 30% bovine lymphocytes were killed by ammonia in medium during 72 hours of incubation. Ammonia also affected the response of lymphocytes to stimulation with PHA or Con A as well as mixed lymphocyte culture reaction. The mitogenic response of lymphocytes was also reduced when lymphocytes were preincubated with ammonia for even 1 hour. The mitogenic response was not restored when the number of lymphocytes preincubated with ammonia was reconstituted to the initial concentration to compensate for the killed lymphocytes before stimulation with PHA. Therefore, addition of ammonia to the culture either killed lymphocytes or permanently impaired their functions.

Tolerance of estuarine benthic diatoms to high concentrations of ammonia, nitrite ion, nitrate ion and orthophosphate

Ten species of benthic diatoms from the Eems-Dollard estuary were cultured unialgally in synthetic media with various concentrations of ammonia (NH4++NH3), nitrite ion, nitrate ion and orthophosphate. Most of the species grew well in media with very high concentrations of nitrite ion (1 to 10 mg-at N l-1), nitrate ion (about 16.9 mg-at N l-1) and orthophosphate (at least 0.9 mg-at P l-1). Ammonia concentrations higher than 0.5 mg-at N l-1 inhibited growth of the cultures. The rate of photosynthesis of diatoms from the field and from cultures was also inhibited by 0.5 mg-at N l-1 of ammonia under certain conditions. Inhibition of photosynthesis by ammonia was strongly enhanced by high irradiance and high pH. It is most unlikely that nitrite ion, nitrate ion and orthophosphate attain concentrations high enough to be inhibitory in the field, but concentrations of ammonia may be high enough for inhibition to occur. However a clear relationship between sensitivity of the diatoms and their occurrence on more or less polluted mudflats was not found.

Effect of ammonia concentration of rumen microbial protein production in vitro.

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.

Kinetics of water-ammonia exchange in the series of aquaamminecobalt(III) complexes. I. Mechanism of the reaction of the diaquatetraamminecobalt(III) ion with ammonia

Kinetic studies at a single temperature and varying ammonia concentration and ionic strength have provided a mechanism for the formation reaction of the hydroxopentaamminecobalt(III) ion from tetraamminecobalt(III) complexes. The principal rate determining step can be interpreted as a dissociative interchange reaction of the Co(NH 3) 4(OH)(H 2O) 2+ ion: coordinated water leaves the first coordination sphere, while an ammonia molecule comes in from the second sphere.

Correlated EPR—Optical Spectra of Potassium in Ethylamine—Ammonia Mixtures

Extensive electron paramagnetic resonance (EPR) studies of potassium in ethylamine—ammonia mixtures were made over a temperature range of −180° to +100°C and at varying ammonia concentrations up to 68 mole %. Hyperfine splittings, g values, linewidths, and spin concentrations were measured. Optical spectra were measured from −65° to +35°C for a number of the solutions. Correlation of optical and EPR results rules out the assignment of the visible absorption to the monomeric species responsible for hyperfine splitting. The unusual temperature dependence of the EPR spectra cannot be explained in the light of current models, nor can the ammonia dependence be quantitatively interpreted. A model involving equilibrium between atoms and monomers quantitatively describes the temperature dependence. To explain the dependence upon ammonia concentration, it is necessary to consider two monomeric species, one fully solvated by ethylamine and the other involving replacement of ethylamine by one molecule of ammonia. Above about 8 mole % ammonia, computer analysis of the EPR spectra showed the building-in of an extra absorption consisting of a single broad line. The intensity of this absorption relative to the four-line pattern continued to increase until the lines merged at about 25 mole % ammonia. Under varying conditions, the optical spectra showed the three peaks characteristic of metal—amine solutions. Relative intensities were very sensitive to temperature and ammonia concentrations. At low ammonia concentrations only the visible absorption was obtained while the intermediate and infrared absorptions occurred at higher concentrations. The latter two peaks were favored by high temperature, while the visible absorption was more pronounced at lower temperatures. These spectra are discussed in the light of current models for metal—amine solutions.

Determination of pH of Ammonia Latex

Abstract The pH of latex has been determined at various concentrations of ammonia (1) by the use of indicators, and (2) by the application of the glass electrode. The two curves thus obtained were comparable but not identical. It is shown that the glass electrode gives results reproducible with a high degree of accuracy up to pH 9.5 and a fair degree of accuracy up to pH 11.0. Above pH 11.0 it is necessary to calibrate each electrode. An ordinary galvanometer allowed measurement of the e. m. f. to 1 millivolt. The assymetry of the glass was so small as to be negligible. This paper covers the work done so far in these laboratories on the development of an accurate and rapid method for determining the pH of latex. From a practical viewpoint one of the most troublesome features of the direct use of a hydrogen electrode is the deposition of a film of rubber on the platinum, which by increasing the internal resistance of the cell, so reduces the sensitivity of the null point instrument that after a few determinations the apparatus must become inoperative. A more serious objection to this electrode is the uncertainty attached to measurements made in solutions containing proteins.