Undissociated Ammonia Research Articles

Assessing the effects of partially decarbonising a diesel engine by co-fuelling with dissociated ammonia

The proven feasibility of ammonia combustion in compression-ignition engines has led to it being considered as a carbon-free replacement for diesel fuel. Due to its high auto-ignition temperature, however, a more realistic strategy would be to aim for a step-change reduction in carbon emissions by co-fuelling a diesel engine with ammonia. In assessing this strategy, ammonia gas was introduced into the air-intake manifold of a compression-ignition engine, while diesel fuel was injected directly into the cylinder to ignite the mixture. By substituting only 3% of the air intake by ammonia, the diesel consumption and the CO2 emissions decreased by 15%. The combustion and emission characteristics were then compared when the same percentage of air intake (by mass) was substituted by either dissociated ammonia (a mixture of H2, N2 with small percentages of NH3) or pure hydrogen, to mimic the other possible forms in which the co-fuel can be delivered to the engine. The addition of pure hydrogen resulted in the best engine performance, both in terms of combustion efficiency and regulated emission quality. The thermal combustion efficiency declined by only ∼0.5% when the H2 was replaced by undissociated ammonia at low load, but N2O now appeared in the emissions. Co-fuelling the engine with dissociated ammonia may provide the ideal compromise in terms of thermal combustion efficiency and emission quality, while also providing a waste-heat recovery mechanism.

Ammonia variations in phytotreatment ponds of land-based fish farm wastewater

The present study reports the results of 2 years monitoring of ammonia present in intensive sea-farm water and in the effluent from phytotreatment ponds (lagooning) to which fish farm wastewater is conveyed before discharge into the Orbetello Lagoon (Tuscany, Italy). The aims were: (1) to evaluate the quality of the water discharged into the receiving environment, which consists of a shallow coastal lagoon with low renewal rate; (2) to assess the effect of lagooning on fish farming wastewater with reference to total ammonia and undissociated ammonia. During the test period, physicochemical parameters were measured using two HYDROLAB Datasonde 3 multiparameter probes. Water samples were taken monthly. Ammonia determinations were performed on a BRAN+LUEBBE AA III Autoanalyzer. Recorded undissociated ammonia concentrations represent a critical water quality element for the receiving environment: the NH 3 during the above period lay between 0.16 and 5.06 μM (annual mean: 1.12±1.21 μM). The increase in pH occurring inside the system appreciably increases undissociated ammonia content as a result of high macroalgal development. The pH pick value (8.56 unity) was recorded in the treatment ponds in October. Undissociated ammonia increases wastewater toxicity, but, at the same time, its volatilization is an important mechanism of nitrogen removal, which reduces the eutrophizing contribution of the wastewater itself.

Thick silicate film by an interfacial polymerization

A thick silica gel film, corresponding to the glass film of 10–20 micron in thickness, has been formed at the interface between two immiscible liquids, hexane and water, using E-40, a partially polymerized silicon alkoxide, as the precursor. The film formation was possible using both acid- and base-catalyzed water, but was greatly dependent on the type of catalyst. Only the trace of a film was observed for the system catalyzed with a strong electrolyte such as HCl, HNO3 or NaOH, while a gel film, corresponding to the glass film of several to 10 micron in thickness was formed with a weak electrolyte such as ammonia, organic acid like acetic acid, citric acid, etc., of similar pH value. The direct introduction of organic base catalyst like triethylamine in hexane was much more effective than the use of ammonia water, suggesting that the polymerization of E-40 to form a gel film takes place in the organic phase, where water molecules, as well as undissociated ammonia or organic acids, can diffuse in.

非解離アンモニア抑制のためのｐＨ制御によるシオミズツボワムシの高密度培養

Two experiments (Exp. I: batch method using 1l vessels and Exp. II: semi-continuous method using 200l tanks) were carried out in order to investigate the effect of acidification of the media in high density cultures of the rotifer Brachionus rotundiformis on the reduction of poisonous undissociated ammonia. Rotifer were cultured in media with pH adjusted to 6, 7 and 8, and without pH adjustment, bubbling oxygen gas and feeding commercial condensed Chlorella regularis. The pH was adjusted with the automatic addition of HCl (35%) and NaOH (10 N) through a pH controller. The concentration of undissociated ammonia in the medium without pH adjustment (Exp. I) and of 8 pH (Exp. II) increased to 27 and 16 ppm, and the growths of rotifer population were inactive and their maximum densities were 8, 000 and 3, 000 individ./ml, respectively. On the other hand, the concentration of undissociated ammonia in the medium of 7 pH remained less than 10 ppm, and in the medium of 6 pH, it was only 2 ppm. The growths of rotifer population in their media were remarkably active, and their maximum densities reached 22, 000 to 34, 000 individ./ml (Exp. I) and 9, 000 to 13, 000 ìndivid./ml (Exp. II).

濃縮淡水クロレラ給餌によるシオミズツボワムシの高密度培養における増殖阻害要因について

In order to investigate the factors inhibiting the growth of rotifer (S-type) in high density cultivation, a series of experiments were conducted, cultivating rotifer in 30l and 1kl vessels by feeding condensed Chlorella. Although there was no difference in the maximum population of rotifer in the culture experiments at different temperatures of 24, 28, and 32°C, the growth rate increased as the culture temperature increased. In the cultivation system supplied with air, the maximum rotifer population did not exceed 4, 000-5, 000 individuals/ml because oxygen levels were restricted due to the accumulation of undissociated ammonia. Feeding oxygen gas to the rotifer culture system enabled high density cultivation with a population of 20, 000 individuals/ml. In such an oxygen-rich culture system, the concentration of undissociated ammonia is considered to be the main factor inhibiting the growth of rotifer.

Effects of pollutants in fresh waters on European non‐salmonid fish I: Non‐metals

As part of a programme of acquiring data for preparing standards to safeguard European, nonsalmonid, freshwater fish from pollution, toxicity tests were carried out in hard, well‐aerated water. Asymptotic median lethal concentrations (LC50s) of undissociated ammonia, cyanide, nitrite and phenol to one or more of three species were determined. The LC50s were as follows: to common carp 16mg1‐1 as NO2–N; to perch 0.1 mg1‐1 as HCN; to roach 0.35 mg1‐1 as NH3‐N, 0‐11mg1‐1 as HCN, 10.1 mg1‐1 asNO2‐Nand 10mg‐1 as phenol. In order to define these LC50s, exposure periods within the range 0.3 days (phenol) to 14 days (nitrite) were required. Comparisons are made with other data and the tentative water quality ‘criteria’ proposed by the European Inland Fisheries Advisory Commission.

30] Glutaminase from mammalian tissues

Publisher Summary This chapter provides an overview of glutaminase from mammalian tissues. The mitochondrial phosphate activated glutaminase (PAG), which is the most important glutaminase in mammalian tissues, is described. Measurement of the reaction products ammonia or glutamate may be used for assay of PAG. Measurement of ammonia suffers from two disadvantages—the great water solubility of this compound makes it difficult to keep the background values sufficiently low and some undissociated ammonia may escape, particularly at prolonged incubations at 37° when the pH exceeds 8.0. Ammonia can be monitored, for example, with Nessler's reagent after microdistillation, by the ammonia electrode, or by coupling to the glutamate dehydrogenase (GDH) reaction, whereby NADH oxidation is measured. The two latter methods permit measurement of enzyme rates. The assay of PAG in isolated mitochondria, synaptosomes, cultured neurons, granulocytes, and astrocytes is reviewed in the chapter. Glutamate formed in a prefixed time is assayed following incubation of the cellular material with L-glutamine (preferably in the physiological concentration range), two concentrations of phosphate (to ensure that PAG is assayed), and inhibitors to prevent the metabolism of glutamate.

The effect of some ammonium salts on nitrate reductase level, onin vivo nitrate reduction and on nitrate content in excisedpisum sativum roots

The effect of some ammonium salts on nitrate reductase (NR) level, onin vivo nitrate reduction and on nitrate content was followed in the presence of nitrate in the medium, under changing experimental conditions, in excisedPisum sativum roots, and their effect was compared with that of KNO3, Ca(NO3)2 and NaNO3 at 15 mM NO3 - concentration, i.e. at a concentration which considerably exceeded the level of saturation with nitrate with respect to nitrate reductase. The effect of ammonium salts on NR level is indirect and changes from a positive one to a strongly negative one which is dependent on the time of action of the salt, on the presence of other cations, on pH of the solution of the ammonium salt and on the nature of the anion of the ammonium salt. A positive effect on the enzyme level can be observed in the presence of other cations than NH4 + at suitable concentrations of those ammonium salts, the solutions of which have their pH values in the acid region (i.e. NH4H2PO4, (NH4)2SO4 and NH4NO3). However their positive effect is independent of the presence of NH4 + ions, and it is obviously the result of an increased concentration of H+ ions. A clear-cut negative effect on NR level can be observed after 24 h in one-salt NH4NO3 solution where NH4 + is not balanced with other cations and thus certainly can adversely influence many metabolic processes, and in the solutions containing neutral (pH 6.2) and dibasic ammonium phosphates in which dissolved undissociated ammonia [(NH3). (H2O) which can also affect many metabolic processes incl. proteosynthesis] probably has a toxic influence.Thein vivo nitrate reduction is always depressed in excised pea roots in the presence of ammonium salts in the medium, regardless of the level of nitrate reductase. Under the described conditions, no relationship could be established between the enzyme level and the so-called metabolic NO3 - pool (i.e. NO2 - production under anaerobic conditions), nor between NR level and the total nitrate content in the roots.One-salt solutions of NaNO3, Ca(NO3)2 and KNO3 exert different effects on the level of nitrate reductase and on the content of NO3 - in the roots, but the in vivo NO3 - reduction shows the same trend as NR level in the roots influenced by these salts. Cl- ions, supplied in NH4C1, depress both NR level and NO3 - content in the roots at higher concentrations, but they do not significantly affect the in vivo nitrate reduction in comparison with other ammonium salts. These results indicate that NR level,in vivo nitrate reduction, and nitrate uptake can be regulated in pea roots independently of each other.

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride at 25°C and the volume changes on ionization

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride are measured up to 2 mol l-1 at 25�C by a combination of pyknometric and dilatometric methods. The apparent molar volume f�V of undissociated ammonia at infinite dilution is found to be 24.85�0.02 cm3 mol-1, and that of NH4Cl is 35.71�0.02 cm3 mol-1. The volume change on ionization for the standard states ΔV� is -29.07�0.04 cm3 mol-1. For aniline the values are: f�V(PhNH2) 89.30, f�V(PhNH3Cl) 102.74 and ΔV� -26.49�0.05 cm3 mol-1.

Differential Action of Ammonium Chloride on the Response of the Sensitized Gut to Ovalbumin, Serotonin, and Histamine

Abstract The presence of physiologically active principles in perfusates of chemically irritated lungs has been described by Steiner (1) and Bartosch (2). Garan (3) insufflated various hydrocarbons and ammonia into the isolated lungs of guinea pigs and found that the output of physiologically active materials, as assayed on the guinea pig gut, was greatest after treatment with ammonia. He inferred that the perfusate contained histamine on the basis that it caused the atropinized gut to contract, and showed the activity of the extract to be reduced after incubating it for 24 hr with the histaminase preparation, Torantil. Subsequent work of Schild (4) showed that the amount of active material produced from the rat's diaphragm by treatment with ammonium chloride varied with the pH of the medium and therefore that the magnitude of the release was dependent upon the fraction of undissociated ammonia present.

THE KINETICS OF PENETRATION

The accumulation of ammonia takes place more rapidly in light than in darkness. The accumulation appears to go on until a steady state is attained. The steady state concentration of ammonia in the sap is about twice as great in light as in darkness. Both effects are possibly due to the fact that the external pH (and hence the concentration of undissociated ammonia) outside is raised by photosynthesis. Certain "permeability constants" have been calculated. These indicate that the rate is proportional to the concentration gradient across the protoplasm of NH(4)X which is formed by the interaction of NH(3) or NH(4)OH and HX, an acid elaborated in the protoplasm. The results are interpreted to mean that HX is produced only at the sap-protoplasm interface and that on the average its concentration there is about 7 times as great as at the sea water-protoplasm interface. This ratio of HX at the two surfaces also explains why the concentration of undissociated ammonia in the steady state is about 7 times as great in the sea water as in the sap. The permeability constant P''' appears to be greater in the dark. This is possibly associated with an increase in the concentration of HX at both interfaces, the ratio at the two surfaces, however, remaining about the same. The pH of sap has been determined by a new method which avoids the loss of gas (CO(2)), an important source of error. The results indicate that the pH rises during accumulation but the extent of this rise is smaller than has hitherto been supposed. As in previous experiments, the entering ammonia displaced a practically equivalent amount of potassium from the sap and the sodium concentration remained fairly constant. It seems probable that the pH increase is due to the entrance of small amounts of NH(3) or NH(4)OH in excess of the potassium lost as a base.

THE ACCUMULATION OF ELECTROLYTES

Experiments on Valonia were carried out as follows: Stage I.-Cells in dim light accumulated 0.08 M ammonia (NH(3) + NH(4)OH + NH(4) (+)) from sea water containing 0.0025 M ammonia (but the concentration of undissociated ammonia appeared to remain less inside than outside). Potassium came out. Stage II.-Cells in dim light in nearly ammonia-free normal sea water lost ammonia which was replaced by sodium entering from the sea water. Potassium in the sap remained practically constant. Stage III.-The cells were placed in stronger light where the loss of ammonia continued and potassium entered. Sodium entered more rapidly than in Stage II. Stage IV.-Cells transferred to sea water containing 0.0025 M ammonia again accumulated ammonia up to 0.1345 M. The results in general harmonize with the view that the direction of movement of a base M through the protoplasm depends on the difference of the activity products (M)(o)(OH)(o) and (M)(i)(OH)(i) where the subscripts o and i refer to sea water and sap respectively. On this basis, if the entrance of ammonia raised the internal concentration of OH sufficiently in Stage I potassium should come out in Stage I, as actually happened. The behavior of sodium is in doubt. If the internal pH in Stage II were sufficiently high sodium should enter but not potassium. This was actually found. In Stage III, if we suppose that the effect of stronger light is to increase the external pH (by photosynthesis) more than the internal pH (as found by Crozier) we can understand why potassium entered, because such an increase in pH could readily make the external value of (K) (OH) greater than the internal. This would also explain why sodium entered more rapidly than in Stage II. When ammonia is coming out of the cell, sodium and potassium may enter more rapidly than usual without raising the internal concentration of halide above a certain critical value at which entrance appears to be checked.

PROTOPLASMIC POTENTIALS IN HALICYSTIS

The nature and origin of the large "protoplasmic" potential in Halicystis must be studied by altering conditions, not only in external solutions, but in the sap and the protoplasm itself. Such interior alteration caused by the penetration of ammonia is described. Concentrations of NH(4)Cl in the sea water were varied from 0.00001 M to above 0.01 M. At pH 8.1 there is little effect below 0.0005 M NH(4)Cl. At about 0.001 M a sudden reversal of the potential difference across the protoplasm occurs, from about 68 mv. outside positive to 30 to 40 mv. outside negative. At this threshold value the time curve is characteristically S-shaped, with a slow beginning, a rapid reversal, and then an irregularly wavering negative value. There are characteristic cusps at the first application of the NH(4)Cl, also immediately after the reversal. The application of higher NH(4)Cl concentrations causes a more rapid reversal, and also a somewhat higher negative value. Conversely the reduction of NH(4)Cl concentrations causes recovery of the normal positive potential, but the threshold for recovery is at a lower concentration than for the original reversal. A temporary overshooting or increase of the positive potential usually occurs on recovery. The reversals may be repeated many times on the same cell without injury. The plot of P.D. against the log of ammonium ion concentration is not the straight line characteristic of ionic concentration effects, but has a break of 100 mv. or more at the threshold value. Further evidence that the potential is not greatly influenced by ammonium ions is obtained by altering the pH of the sea water. At pH 5, no reversal occurs with 0.1 M NH(4)Cl, while at pH 10.3, the NH(4)Cl threshold is 0.0001 M or less. This indicates that the reversal is due to undissociated ammonia. The penetration of NH(3) into the cells increases both the internal ammonia and the pH. The actual concentration of ammonium salt in the sap is again shown to have little effect on the (P.D.) The pH is therefore the governing factor. But assuming that NH(3) enters the cells until it is in equilibrium between sap and sea water, no sudden break of pH should occur, pH being instead directly proportional to log NH(3) for any constant (NH(4)) concentration. Experimentally, a linear relation is found between the pH of the sap and the log NH(3) in sea water. The sudden change of P.D. must therefore be ascribed to some system in the cell upon which the pH change operates. The pH value of the sap at the NH(3) threshold is between 6.0 and 6.5 which corresponds well with the pH value found to cause reversal of P.D. by direct perfusion of solutions in the vacuole.

THE PERMEABILITY OF THE ARBACIA EGG TO AMMONIUM SALTS

1. The rate of swelling of Arbacia eggs in solutions isosmotic with sea water of the ammonium salts of the first five saturated fatty acids has been found to be in the order: valerate>butyrate>propionate> acetate>formate.2. In solutions of these salts made up in bicarbonate-free sea water or in M/2 KCl recovery of the original volume after a preliminary shrinkage follows the same order.3. Within the pH range from approximately 7.8 to 6.2 the rate of swelling increases with increasing acidity. Under certain conditions a further lowering of the pH may reverse the effect.4. No significant changes in volume occur in solutions of ammonium nitrate or chloride, though cells exposed to such solutions for over an hour are still capable of swelling in ammonium acetate.5. These results agree with the theory suggested by Jacobs, that there is no appreciable penetration of either the salt or its ions as such but that undissociated ammonia and fatty acid, formed by hydrolysis of the salt, penetrate the cell separately, uniting again after their entrance.6. The rate of entrance of the acid, rather than that of the ammonia, usually appears to be the limiting factor in determining the rate of swelling of the cell.