Search results for "AMMONIA"

A new multi analytical approach for the identification of synthetic and natural dyes mixtures. The case of orcein-mauveine mixture in a historical dr…

2017

In this paper, the application of a multi-analytical approach for the characterisation of synthetic and natural dyes in a historical textile is presented. The work is focused on a historical dress of a Sicilian noblewoman, dating from about 1865–1870. Firstly, SERS on fibre was performed, in order to individuate the classes of dyes employed. The SERS spectra suggested the presence of two main dyes: mauveine and orcein. In order to confirm these preliminary results, two different extraction protocols were applied. The extracts obtained were analysed by ESI-MS, MALDI-ToF and UHPCL-MS analyses, confirming the SERS results. In particular, the application of the ammonia mild extraction technique…

Deuterium hyperfine splittings in the rotational spectrum of NH2D as revealed by Lamb-dip spectroscopy

2020

Abstract In the context of radio-astronomical observations, laboratory experiments constitute a cornerstone in the interpretation of rich line surveys due to the concomitant presence of numerous emitting molecules. Here, we report the investigation of three different rotational transitions of mono-deuterated ammonia (NH2D), a species of astrophysical interest, for which the contribution of the deuterium nuclear spin to the rotational spectrum has been resolved for the first time in the millimeter- and submillimeter-wave domain. The effect of hyperfine interactions on the rotational spectrum has been unveiled by a combined theoretical and experimental approach. Quantum-chemical calculations …

Monitoring pH and ORP in a SHARON reactor

2011

This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been achieved by adding methanol at the beginning of anoxic stages. Time evolution of pH and ORP along each cycle allows identifying the decrease in nitritation rate when ammonia is consumed during the aerobic phase and the end of the denitrification process during the anoxic phase. Therefore, monitoring pH…

Effect of pH and HNO2 concentration on the activity of ammonia-oxidizing bacteria in a partial nitritation reactor

2013

Ammonia-oxidizing bacteria (AOB) are very sensitive to environmental conditions and wastewater treatment plant operational parameters. One of the most important factors affecting their activity is pH. Its effect is associated with: NH3/NH4 þ and HNO2/NO2 chemical equilibriums and biological reaction rates. The aim of this study was to quantify and model the effect of pH and free nitrous acid (FNA) concentration on the activity of AOB present in a lab-scale partial nitritation reactor. For this purpose, two sets of batch experiments were carried out using biomass from this reactor. Fluorescent in situ hybridization analysis showed that Nitrosomona eutropha and Nitrosomona europaea species we…

Elaboration of ammonia gas sensors based on electrodeposited polypyrrole - cobalt phthalocyanine hybrid films

2013

The electrochemical incorporation of a sulfonated cobalt phthalocyanine (sCoPc) in conducting polypyrrole (PPy) was done, in the presence or absence of LiClO4, in order to use the resulting hybrid material for the sensing of ammonia. After electrochemical deposition, the morphological features and structural properties of polypyrrole/phthalocyanine hybrid films were investigated and compared to those of polypyrrole films. A gas sensor consisting in platinum microelectrodes arrays was fabricated using silicon microtechnologies, and the polypyrrole and polypyrrole/phthalocyanine films were electrochemically deposited on the platinum microelectrodes arrays of this gas sensor. When exposed to a…

Biofiltration System for Purification of Composting Waste Gases

2006

The biofiltration technique for the purification of polluted air from composting facility volatile compounds was studied. Two different biowaste composting techniques were compared with regard to emission of NH3 and H2S. The ammonia removal was observed in aerobic phase of active composting period, respectively H2S in anaerobic phase. Biofiltration process was realized in modified solid- state fermentation system (SSF). The biodegradation of volatile compounds was investigated in one and two stage systems with inert packing material and hemoautotrofic microorganisms designed DN-1 (Pseudomonas sp.), DN-2 (Nitrisomonas sp.), DN-3 (Nitrobacter sp.) and DN-13 (Sarcina sp.) and Thiopharus-3. The…

( E )‐ und ( Z )‐Enole von β‐Ketocarbonsäureamiden

1990

(E)- and (Z)-Enols of β-Ketocarboxylic Acid Amides Reaction of dimesitoyldiazomethane (1) with ammonia (3a), primary and secondary amines (3b – o and 3p – v, respectively) leads to the completely enolized amides 4a – v. Besides the chelated Z configuration the unusual E isomer exists in the most cases, too. The Z/E distribution in the equilibrium depends on the steric and electronic effects present in the amide group CONR2R3 and on the solvent.

Herstellung und 13 C‐NMR‐Spektroskopie isomerer 1,4‐Heterophosphorinanium‐Salze

1978

Die quartaren Diallylphosphonium-Salze 1–8 werden mit Natronlauge, Natriumhyrogensulfid. Ammoniak oder prim. Aminen zu den 1,4-Oxa- (9–14), 1,4-Thia- (15–21) und 1,4-Azaphosphorinanium-Salzen (22–36) umgesetzt. Die Konformation bzw. Konfiguration der in den meisten Fallen als Isomerengemische anfallenden Salze 9–36 wird 1H- bzw. 13C-NMR-spektroskopisch untersucht. Eine Abhangigkeit von der geometrischen Anordnung sowohl der 4JPH- als auch der vicinalen3JPC-Kopplungskonstanten konnte bei diesen nicht gespannten 1,4-Diheterocylohexanen festgestellt werden. Synthesis and 13C NMR Spectra of Isomeric 1,4-Heterophosphorinanium Salts The phosphonium salts 1–8 react with aqueous sodium hydroxide, s…

Ammoniates of Uranium Trichloride and Tetrachloride

1965

Chronic exposure to ammonia induces isoform-selective alterations in the intracellular distribution and NMDA receptor-mediated translocation of prote…

2004

Hyperammonemia is responsible for most neurological alterations in patients with hepatic encephalopathy by mechanisms that remain unclear. Hyperammonemia alters phosphorylation of neuronal protein kinase C (PKC) substrates and impairs NMDA receptor-associated signal transduction. The aim of this work was to analyse the effects of hyperammonemia on the amount and intracellular distribution of PKC isoforms and on translocation of each isoform induced by NMDA receptor activation in cerebellar neurons. Chronic hyperammonemia alters differentially the intracellular distribution of PKC isoforms. The amount of all isoforms (except PKC zeta) was reduced (17-50%) in the particulate fraction. The con…