A Laboratory Study on the Role of Stream Sediment in Nitrogen Loss from Water

Parameters that affect chunky graphite formation in heavy-section castings have been studied in previous works which showed that inoculation and cerium addition both increase the tendency for this degenerate graphite. This suggested that laboratory study on chunky graphite formation could be performed on small castings by over-treating the melt. Though the role of silicon was not ascertained, it appeared of potential interest to also investigate its effect in relation with the carbon equivalent of the iron and the nucleation potential of the melt. Keel-blocks were thus cast using Ce or Ce-Mg treated melts, with increased silicon content (up to 4.0 wt.%) and inoculation rate as compared to usual practice. It was observed that chunky graphite systematically appeared in more or less extended areas centred on the upper part of the keel-blocks. The as-cast microstructure (graphite shape and distribution) has then been studied in relation to melt composition and additions (Ce treatment and inoculation) in both affected and non-affected areas. Finally, microanalysis of oxides and other minor phases showed them to be similar to those appearing in heavy-section castings. It may then be concluded that chunky graphite appears in light-section castings in the same way than in heavy-section castings when using over-treated melts.

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Role of steel and zinc coating thickness in cut edge corrosion of coil coated materials in atmospheric weathering conditions; Part 1: Laboratory study

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2016.06.013 ◽

2016 ◽

Vol 99 ◽

pp. 356-364 ◽

Cited By ~ 13

Author(s):

T. Prosek ◽

A. Nazarov ◽

H.B. Xue ◽

S. Lamaka ◽

D. Thierry

Keyword(s):

Laboratory Study ◽

Coating Thickness ◽

Zinc Coating ◽

Cut Edge ◽

Coated Materials

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Process Control Limits from a Laboratory Study on the Ni(0)-Mediated Coupling of Ethyl Acrylate with a C-22 Steroidal Iodide: A Case Study on the Role of Experimental Design in Highly Developed Processes

Organic Process Research & Development ◽

10.1021/op049908q ◽

2004 ◽

Vol 8 (5) ◽

pp. 769-776 ◽

Cited By ~ 6

Author(s):

Susan D. Van Arnum ◽

Harold Moffet ◽

Barry K. Carpenter

Keyword(s):

Experimental Design ◽

Process Control ◽

Laboratory Study ◽

Ethyl Acrylate ◽

Control Limits

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A Quantitative Study of Nitrogen Loss From Water of a Small, Spring-Fed Stream

Water Quality Research Journal ◽

10.2166/wqrj.1975.013 ◽

1975 ◽

Vol 10 (1) ◽

pp. 110-117 ◽

Cited By ~ 4

Author(s):

N.K. Kaushik ◽

J.B. Robinson ◽

P. Sain ◽

H.R. Whiteley ◽

W. Stammers

Keyword(s):

Aquatic Macrophytes ◽

Nitrate Nitrogen ◽

Nitrogen Loss ◽

Stream Sediments ◽

Nitrogen Transport ◽

Riparian Plants ◽

Nitrate N ◽

Decomposition Of Organic Matter ◽

Kjeldahl Nitrogen

Abstract With a view to determining nitrogen sink processes, if any, in streams and the factors that govern these processes, nitrogen transport was studied in a 2 km-long, perennial, spring-fed stream during the summer months of 1973 and 1974. Concentrations of ammonium, nitrite and Kjeldahl nitrogen were small but those of nitrate nitrogen were unusually high. However, as the water moved downstream it progressively lost nitrate N. This loss represented 59.4% and 46.7% of the respective inputs during 1973 and 1974. The decrease in the concentration of nitrate N could neither be attributed to dilution nor to nitrogen immobilization during decomposition of organic matter nor to the uptake by aquatic macrophytes. Laboratory experiment showed that the stream sediments have significant, capacity for denitrification of nitrate in water overlying them, even when the water is thoroughly oxygenated. Although the role of riparian plants in the uptake of nitrogen has not been fully elucidated, it seems that denitrification in the stream sediment may act as an important permanent nitrogen sink.

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