The SF6 Tracer Technique: Methane Measurement From Ruminants

2007 ◽  
pp. 33-67 ◽  
Author(s):  
K.A. Johnson ◽  
H.H. Westberg ◽  
J.J. Michal ◽  
M.W. Cossalman
Keyword(s):  
Tracer Technique ◽  
Methane Measurement

Studies of Vitamin B12 Metabolism in Patients with Chronic Hepatitis and Liver Cirrhosis

1968 ◽  
Vol 07 (04) ◽  
pp. 371-387
Author(s):  
T. Spârchez ◽  
B. Gheorghescu ◽  
Gh. Jovin ◽  
Elena Merculiev
Keyword(s):  
Liver Cirrhosis ◽  
Chronic Hepatitis ◽  
Vitamin B12 ◽  
Tracer Technique ◽  
Storage Compartment ◽  
And Storage

SummaryWe have studied the kinetiks of vitamin B12 and especially the liver compartment, in 28 normals and 76 patients with chronic hepatitis and liver cirrhosis.The study was carried out by means of vitamin B12 58Co, administered per os (alone or followed by “flushing dosis”), vitamin B12 57Co administered intravenously and by double tracer technique.Our results indicate the Pertubation of intrahepatic storage compartment of radiocobalamine, in patients with chronic hepatitis and especially in patients with active hepatitis and in cirrhotics.This deficiency can be explained probably, by an alteration of the transport to the liver of the absorbed vitamin B12, by an inadequate chemical forme, by hepatic enzymatic disturbances or by excessive handling and storage in extrahepatic compartment.

Experimental Measurement of Turbulent Diffusion, Initial Dilution and T90

1986 ◽  
Vol 18 (11) ◽  
pp. 131-140
Author(s):  
Edmundo Garcia Agudo ◽  
Jose Leomax dos Santos
Keyword(s):  
Experimental Measurement ◽  
Tracer Technique ◽  
Initial Dilution ◽  
Coastal Cities ◽  
Actual Solution ◽  
The World ◽  
Visual Aid ◽  
Proper Design ◽  
Key Aspects ◽  
Bacterial Concentrations

The final disposal of sewage using submarine outfalls has become an actual solution for coastal cities all over the world. In order to get the best results it is necessary to carry out specific studies for the proper design of the outfall. Dilution and decrease in bacterial concentrations are two key aspects for the design. Radioisotope tracers have been used extensively in studies performed in some Brazilian waterbodies where outfall systems exist or are to be installed. As far as dilution measurement is concerned, both point and continuous radiotracer injections can provide useful results. The T90 measurements can be better accomplished using a combined tracer technique for sampling the sewage field, using the radiotracer for dilution measurement and rhodamine B as a visual aid. Typical results of dilution measurement using both techniques mentioned, as well as a summary of T 90 results obtained for the Santos, Fortaleza and Maceió outfalls are presented.

A Tracer Technique to Measure Deposition of Stack Emissions

AIHAJ ◽  
1960 ◽  
Vol 21 (5) ◽  
pp. 343-349 ◽  
Author(s):  
E. J. Schulz ◽  
R. A. Duffee ◽  
R. I. Mitchell ◽  
E. W. Ungar
Keyword(s):  
Tracer Technique ◽  
Stack Emissions

Within- and between-animal variance in methane emissions in non-lactating dairy cows

2008 ◽  
Vol 48 (2) ◽  
pp. 124 ◽  
Author(s):  
J. B. Vlaming ◽  
N. Lopez-Villalobos ◽  
I. M. Brookes ◽  
S. O. Hoskin ◽  
H. Clark
Keyword(s):  
Sulfur Hexafluoride ◽  
Energy Levels ◽  
Tracer Technique ◽  
Ch4 Emissions ◽  
Ch4 Production ◽  
Lactating Dairy Cows ◽  
Coefficients Of Variation ◽  
Lactating Dairy Cattle ◽  
Over Time

Several studies on methane (CH4) emissions have focussed on selecting high and low CH4-emitting animals. One challenge faced by this work is the lack of consistency, or repeatability, in animal rankings over time. Repeatability for individual animals over time needs to be high to reliably detect high and low CH4-emitting animals. A possible explanation for the lack of repeatability is a relatively high within-animal variation in daily CH4 emissions, meaning that animals could then change their ranking when compared at different points in time. An experiment was undertaken with four non-lactating dairy cattle to assess the within- and between-animal variation in CH4 emissions over time when measured using the sulfur hexafluoride (SF6) tracer technique. Two contrasting diets were fed to the cattle at maintenance energy levels: lucerne silage (diet 1) and a cereal + lucerne + straw mixed ration diet (diet 2). Daily CH4 measurements were undertaken for 23 days on diet 1 and 30 days on diet 2. There was a significant (P < 0.001) difference between diet 1 and diet 2 in daily CH4 production, with mean (±s.e.) production of 124.3 (11.1) g CH4/day from diet 1 and 169.8 (±11.0) g CH4/day from diet 2. Lower CH4 yield (g CH4/kg dry matter intake) was recorded on diet 1 (22.8 ± 2.0) than diet 2 (32.0 ± 2.0). Cows differed significantly (P < 0.05) from one another in daily CH4 yield (diet 1: cow 1 = 19.4 ± 0.6, cow 2 = 22.2 ± 0.8, cow 3 = 23.2 ± 0.7, cow 4 = 25.4 ± 0.6; diet 2: cow 1 = 26.0 ± 0.7, cow 2 = 36.4 ± 0.7, cow 3 = 29.3 ± 0.7, cow 4 = 36.6 ± 0.7). Variances for daily CH4 yield were smaller for diet 1 (within animal = 6.91, between animals = 6.23) than for diet 2 (within animal = 10.09, between animals = 27.79). Estimates of repeatability (variation between animals/total variation) for daily CH4 yield were 47 and 73% in diet 1 and 2, respectively. Coefficients of variation in average daily CH4 emissions in this experiment ranged from 8 to 18% despite the fact that each animal received the same quantity and quality of feed each day. While further research is required, the high within-animal variability in CH4 emissions measured using the SF6 tracer technique may explain why there has been difficulty in obtaining consistent rankings in CH4 yields when animals are measured on multiple occasions. The results also suggest that the SF6 tracer technique may exaggerate apparent between animal differences in CH4 emissions.

Methane emissions from young and mature dairy cattle

2016 ◽  
Vol 56 (11) ◽  
pp. 1897 ◽  
Author(s):  
C. A. Ramírez-Restrepo ◽  
H. Clark ◽  
S. Muetzel
Keyword(s):  
New Zealand ◽  
Emission Factor ◽  
Dry Matter ◽  
Sulfur Hexafluoride ◽  
Dry Matter Intake ◽  
Tracer Technique ◽  
Ch4 Emissions ◽  
Dairy Heifers ◽  
Age Related ◽  
The Mean

Daily methane (CH4) emissions (g) and CH4 yield (g/kg dry matter intake) were measured from 10 dairy heifers (<1 year old) and nine rumen-fistulated cows (>6 years old) fed ryegrass (Lolium perenne) chaffage indoors. The CH4 emissions were estimated using the sulfur hexafluoride tracer technique in four ~5-day periods beginning in June 2008 and repeated 4, 6 and 7 months later. Respiratory chambers were used in four ~13-day periods beginning in November 2008 and repeated 2, 5 and 6 months later. Third and fourth sulfur hexafluoride tracer periods overlapped with the first and second chamber measurement periods, respectively. Averaged over the four measurement periods the CH4 yields determined using both techniques were similar for heifers and cows. The mean CH4 yield estimated by the sulfur hexafluoride tracer technique was 25.3 ± 0.52 for heifers and 24.1 ± 0.55 for mature cows, whereas the mean CH4 yield measured in respiratory chambers was 23.7 ± 0.66 for heifers and 23.6 ± 0.66 for mature cows. Averaged over the eight measurements irrespective of technique, CH4 yields for heifers (24.5 ± 0.42) and cows (23.8 ± 0.43) were similar. There was also no difference between CH4 methods for assessing CH4 yield during the overlapping measurement periods. It was concluded that no consistent differences in CH4 yield existed between heifers and mature cows. Therefore, we do not recommend adoption of an age-related emission factor for cattle in the national inventory calculations for New Zealand.

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