Compared Study of Radiolysis-Induced Gas Liberation in Rocksalt from Various Origins

1992 ◽  
Vol 294 ◽  
Author(s):  
N. Akram ◽  
J.C. Blanchard ◽  
M.T. Gaudez ◽  
P. Toulhoat
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Gas Production ◽  
Spent Fuel ◽  
Γ Irradiation ◽  
Consumption Ratio ◽  
Initial Stage ◽  
High Doses ◽  
Organic Fluids

ABSTRACTThe evolution of impure rocksalt samples under irradiation has been investigated and compared to the evolution of pure halite, concerning the radiolytic release of gases. Four different types of rocksalt (pure halite, anhydrite-bearing, sylvinite-bearing, and marneous) have been irradiated with spent fuel at doses ranging from 104Gy to 107Gy, under synthetic air or helium at 50°C, 150°C, and 200°C. Marneous and anhydrite-bearing salt produced higher amounts of gas than the two other types, especially for H2, CO, and CH4. Radiolytic gas production essentially originates from the decomposition of traces of different kind of impurities : fluid inclusions, which can be composed of brine and/or organic fluids and gases; minerals such as carbonates, sulfates, or hydrated minerals; organic matter, in general (kerogen). Pure halite decomposes only at very high doses (more than 107Gy) giving off some Cl2 and other corrosive gases. Gas production increases steadily with dose for H2, CO, and CH4, contrary to what is observed for the pure Asse salt, where H2 and CO, respectively, peak at 106, and 105 Gy. The increase, with dose, in the production of CH4, C2H6, and C3H8 is far higher for marneous salt and higher for anhydrite-bearing salt. The decrease of the O2/N2 (oxygen consumption) ratio in the irradiation atmosphere is in the following order: marneous>anhydrite>halite=sylvinite. The overall effect of γ-irradiation on impure rocksalt can be described as follows : destruction of organic matter that produces chemically reduced gases (H2, CO, hydrocarbons), after an initial stage of oxygen consumption, which is reached more or less quickly, depending on the availability and quantity of organic matter. The use of impure, i.e, organic matter-bearing salt, as host-rock or engineered barrier for nuclear wastes, may be questioned, because of the high amount of gases produced in the immediate vicinity of the container (explosion hazards, pressure build-up). The present study will be followed by a modelling of the in-situ radiolytic gas production, taking into account: 1) the dose distribution with time, 2) the temperature distribution with time, and 3) the geometry of the repository, and will allow us to estimate the potentiel safety impact of radiolytic gas production in the case of a repository emplaced in impure rocksalt.

Palatability,in situandin vitronutritive value of dried sainfoin (Onobrychis viciifolia)

2010 ◽  
Vol 148 (6) ◽  
pp. 723-733 ◽  
Author(s):  
H. KHALILVANDI-BEHROOZYAR ◽  
M. DEHGHAN-BANADAKY ◽  
K. REZAYAZDI
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Nutritive Value ◽  
Nutrient Content ◽  
Gas Production ◽  
Metabolizable Energy ◽  
Acid Detergent Fibre

SUMMARYThe current study was conducted to determine chemical composition, nutrient content and availability, metabolizable energy (ME) content and nutritive value of sainfoin hay for ruminants. Three ruminally cannulated Holstein cows were used forin situandin vivoexperiments, to determine rumen degradability and digestibility of sainfoin hay. Apparent total tract digestibility of nutrients was determined with feeding of sainfoin hay as the sole diet to achieve 10% more than maintenance energy requirements. Six Zandi ewes were used in the palatability experiment. Means for dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and condensed tannins (CTs) of sainfoin hay were: 940·4 g/kg and 93·43, 12·13, 47·87, 43·33 and 2·13 g/kg DM, respectively.In situeffective degradability of CP and DM were 0·38 and 0·54 g/g with a ruminal outflow rate of 0·05/h, respectively. OM apparent digestibility was in the range of 0·592–0·689, respectively, for Tilley & Terry and total faecal collection assays. ME content of sainfoin hay, according to different methods (gas production,in vitroandin vivodetermined digestible organic matter in dry matter (DOMD)) was in the range 6·87–10·11 MJ/kg DM. Metabolizable protein (MP) content was 483·4 g/kg CP. Sainfoin was more palatable than alfalfa for sheep. It was concluded that sainfoin has a potential use in ruminant rations, especially if environmental conditions are not suitable for alfalfa production.

scholarly journals Stark Contrast in Denitrification and Anammox across the Deep Norwegian Trench in the Skagerrak

2013 ◽  
Vol 79 (23) ◽  
pp. 7381-7389 ◽  
Author(s):  
Mark Trimmer ◽  
Pia Engström ◽  
Bo Thamdrup
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Sediment Cores ◽  
Anammox Bacteria ◽  
Ammonium Oxidation ◽  
Oxygen Penetration ◽  
Anammox Activity ◽  
Redfield Ratios ◽  
First Time

ABSTRACTEnvironmental anaerobic ammonium oxidation (anammox) was demonstrated for the first time in 2002, using15N labeling, in homogenized sediment from the Skagerrak, where it accounted for up to 67% of N2production. We returned to some of these original sites in 2010 to make measurements of nitrogen and carbon cycling under conditions more representative of thosein situ, quantifying anammox and denitrification, together with oxygen penetration and consumption, in intact sediment cores. Overall, oxygen consumption and N2production decayed with water depth, as expected, but the drop in N2production was relatively more pronounced. Whereas we confirmed the dominance of N2production by anammox (72% and 77%) at the two deepest sites (∼700 m of water), anammox was conspicuously absent from two shallower sites (∼200 m and 400 m). At the shallower sites, we could measure no anammox activity with either intact or homogeneous sediment, and quantitative PCR (16S rRNA) gave a negligible abundance of anammox bacteria in the anoxic layers. Such an absence of anammox, especially at one locale where it was originally demonstrated, is hard to reconcile. Despite the dominance of anammox at the deepest sites, anammox activity could not make up for the drop in denitrification, and assuming Redfield ratios for the organic matter being mineralized, the estimated retention of fixed N actually increased to 90% to 97% of that mineralized, whereas it was 80% to 86% at the shallower sites.

Concentrate foods: is all degraded organic matter fermented?

1998 ◽  
Vol 22 ◽  
pp. 262-263
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D. I. Givens ◽  
E. Owen
Keyword(s):  
Protein Synthesis ◽  
Organic Matter ◽  
Gas Production ◽  
Microbial Protein ◽  
Atp Production ◽  
Microbial Protein Synthesis ◽  
End Products

The in situ and in vitro techniques have been adopted to estimate the degradability of organic matter (OM) in the rumen on the basis that this provides an estimate of ATP for microbial protein synthesis. However this assumption may be incorrect since ATP production requires the fermentation of degraded carbohydrate and Beever (1993) has shown that some degraded hexose can be used synthetically without ATP production. In addition, degraded OM from protein is likely to produce less ATP than the same amount of degraded carbohydrate. The gas production (GP) technique measures end products of fermentation and may be a better guide to ATP production. On the assumption that the in situ and in vitro techniques provide satisfactory estimation of OM degradability, the work discussed here used the GP technique to estimate the effective unfermentable OM fraction of the degraded OM (EUFDOM) for a range of concentrate foods.

Rotary Beveling for In Situ Thin-Section Microscopy of Cell Cultures

1981 ◽  
Vol 39 ◽  
pp. 550-551
Author(s):  
Dean A. Handley ◽  
Jack T. Alexander ◽  
Shu Chien
Keyword(s):  
Cell Growth ◽  
Cell Cultures ◽  
Molecular Interactions ◽  
Convenient Method ◽  
Petri Dish ◽  
Simple Method ◽  
Thin Section Microscopy ◽  
Thin Sectioning ◽  
Organic Fluids

In situ preparation of cell cultures for ultrastructural investigations is a convenient method by which fixation, dehydration and embedment are carried out in the culture petri dish. The in situ method offers the advantage of preserving the native orientation of cell-cell interactions, junctional regions and overlapping configurations. In order to section after embedment, the petri dish is usually separated from the polymerized resin by either differential cryo-contraction or solvation in organic fluids. The remaining resin block must be re-embedded before sectioning. Although removal of the petri dish may not disrupt the native cellular geometry, it does sacrifice what is now recognized as an important characteristic of cell growth: cell-substratum molecular interactions. To preserve the topographic cell-substratum relationship, we developed a simple method of tapered rotary beveling to reduce the petri dish thickness to a dimension suitable for direct thin sectioning.

Nucleation and initial growth of Pd2Si crystals on Si(111)

1993 ◽  
Vol 51 ◽  
pp. 844-845
Author(s):  
Xianghong Tong ◽  
Oliver Pohland ◽  
J. Murray Gibson
Keyword(s):  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Initial Growth ◽  
Surface And Interface ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Initial Stage ◽  
Effect Of Surface

The nucleation and initial stage of Pd2Si crystals on Si(111) surface is studied in situ using an Ultra-High Vacuum (UHV) Transmission Electron Microscope (TEM). A modified JEOL 200CX TEM is used for the study. The Si(111) sample is prepared by chemical thinning and is cleaned inside the UHV chamber with base pressure of 1x10−9 τ. A Pd film of 20 Å thick is deposited on to the Si(111) sample in situ using a built-in mini evaporator. This room temperature deposited Pd film is thermally annealed subsequently to form Pd2Si crystals. Surface sensitive dark field imaging is used for the study to reveal the effect of surface and interface steps.The initial growth of the Pd2Si has three stages: nucleation, growth of the nuclei and coalescence of the nuclei. Our experiments shows that the nucleation of the Pd2Si crystal occurs randomly and almost instantaneously on the terraces upon thermal annealing or electron irradiation.

Characterisation of production of organic rich topsoil from sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 195-201 ◽  
Author(s):  
P. Andreasen ◽  
P. B. Mortensen ◽  
A. Stubsgaard ◽  
B. Langdahl
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Mineral Soil ◽  
Climatic Conditions ◽  
Growth Media ◽  
Soil Mixture ◽  
Water Suspension ◽  
Aerobic Process ◽  
Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

scholarly journals Evaluation of the Nutrient Composition, In Vitro Fermentation Characteristics, and In Situ Degradability of Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus in Cattle

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Kim Margarette C. Nogoy ◽  
Jia Yu ◽  
Young Gyu Song ◽  
Shida Li ◽  
Jong-Wook Chung ◽  
...  
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Gas Production ◽  
Nutrient Composition ◽  
Neutral Detergent Fiber ◽  
Amaranthus Cruentus ◽  
Amaranthus Caudatus ◽  
Amaranthus Hypochondriacus

The amaranth plants showed high potential feed value as forage for ruminants. An in-depth study of this plant, particularly in cattle, will help extend its utilization as an alternative protein and fiber feed source in cattle feeding. In this study, the nutrient compositions of three different species of amaranth, Amaranthus caudatus L., Amaranthus cruentus L., and Amaranthus hypochondriacus L.—two varieties for each species, A.ca 74, A.ca 91, A.cu 62, A.cu 66, A. hy 30, and A. hy 48—were evaluated. The in vitro technique was used to evaluate the fermentation characteristics such as total gas production, total volatile fatty acids (VFA) concentration, pH, and ammonia concentration of the rumen fluid. Moreover, the effective degradabilities of dry matter (EDDM) and crude protein (EDCP) of the amaranth forages were determined through in situ bag technique. The amaranth forages: A. caudatus, A. cruentus, and A. hypochondriacus showed better nutritive value than the locally produced forages in Chungcheong province of Korea. The CP of the amaranth ranged from 11.95% to 14.19%, and the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents ranged from 45.53% to 70.88% and 34.17% to 49.83%, respectively. Among the amaranth varieties, A. hypochondriacus 48 showed the most excellent ruminant feed nutrient quality (CP, 14.19%; NDF, 45.53%; and ADF, 34.17%). The effective degradabilities of dry matter (EDDM; 33–56%) and crude protein EDCP (27–59%) of the amaranth were lower compared to other studies, which could be due to the maturity stage at which the forages were harvested. Nonetheless, A. hypochondriacus 48 showed the highest EDDM (56.73%) and EDCP (59.09%). The different amaranth species did not differ greatly in terms of total VFA concentration or molar proportions, total gas production, or ammonia-N concentration. The high nutrient composition, and highly effective degradability of dry matter and crude protein, coupled with the favorable fermentation characteristics, suggest that the amaranth forages showed good to excellent feed quality for cattle.

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