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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Entwicklung eines verteilt-geregelt belüfteten Filtersystems zur biologischen Behandlung von methanhaltigen Deponieschwachgasen /

Haubrichs, Roland. January 2007 (has links)
Zugl.: Duisburg, Essen, Universiẗat, Diss., 2007.
12

Modellierung der Struktur von fluidem Methan mit der Reversen Monte Carlo Methode

Bassen, Angelika. January 1994 (has links)
Stuttgart, Univ., Fakultät Chemie, Diplomarb., 1994.
13

Experimentelle und numerische Untersuchung magerer Methan-Hochdruckverbrennung unter Mikrogravitation

Hyvönen, Jari Johannes. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 2000--Aachen.
14

Simulation der katalytischen Methangaskonversion an Platin

Wolf, Markus. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2000--Heidelberg.
15

Entwicklung und Einsatz eines Diodenlaserspektrometers zum quantitativen In-situ-Nachweis von Methan und Wasser in der Stratosphäre

Giesemann, Carsten. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2003--Heidelberg.
16

Effekte verschiedener Kohlenhydrate (Cellulose, Pektin, Stärke und Inulin) auf die Wasserstoff- und Methanexhalation beim gesunden Pferd

Mößeler, Anne Katrin. Unknown Date (has links) (PDF)
Tierärztl. Hochsch., Diss., 2004--Hannover.
17

Verfahrenstechnische Untersuchungen zur Optimierung der Biogasgewinnung aus nachwachsenden Rohstoffen

Ohly, Nils 20 July 2009 (has links) (PDF)
In kontinuierlichen Gärversuchen für unterschiedliche nachwachsende Rohstoffe in Mono- und Cofermentation wurden die Grenzen der Prozessstabilität ermittelt. Als Kennwert für die Optimierung und den direkten Vergleich der Gärversuche ist nur die Methangasproduktion in m3 Methan/(m3 Fermentervolumen* d) geeignet. In der Cofermentation der nachwachsenden Rohstoffe mit Rindergülle konnten Synergieeffekte nachgewiesen werden, die zu einem verbesserten anaeroben Abbau der Biomasse führten. Die Anwendung des zweistufigen Verfahrens auf die Vergärung von Gerstenkörnern führte zu keiner Verbesserung der Prozessstabilität und der Methangasproduktion. Die Vorausberechnung der Methangasausbeute mit Hilfe des Futterwertes führte nur zu einer qualitativen Vergleichbarkeit unterschiedlicher Substratklassen und gab nicht die tatsächliche Methangasausbeute im Vergärungsversuch wieder.
18

Increased target volume and hydrogen content in [11C]CH4 production

Helin, S., Arponen, E., Rajander, J., Aromaa, J., Johansson, S., Solin, O. 19 May 2015 (has links) (PDF)
Introduction High starting radioactivity is usually advantageous for producing radiopharmaceuticals with high specific radioactivity. However, the [11C]CH4 yields from N2-H2 gas target fall short from theoretical amounts, as calculated from the cross section for the well-known 14N(p,α)11C nuclear reaction1. The beneficial effect of increased target chamber temperature on [11C]CH4 yields has recently been brought forward by us2 and others3. In addition to the temperature effect, our attention has also been on the hydrogen content factor. This study intends to examine the N2-H2 target performance in a substantially larger target chamber and at higher temperatures than our setup before and compare the results to the existing data. Materials and Methods Aluminium bodied custom design target chamber is used in fixed 17 MeV proton beam irradiations. Target chamber is equipped with heating elements and cooling circuit for temperature control. In addition to the target chamber body temperature, the target gas loading pressure and irradiation current can be varied. The irradiation product is collected into an ad-sorbent trap that was immersed in a liquid argon cooling bath within a dose calibrator. Results and Conclusion Pursued data will show [11C]CH4 saturation yields (Ysat [GBq/µA]) at different irradiation and target parameters.
19

Microbial dynamics in a glycolate fed biogas reactor influenced by abiotic parameters

Reinert, Susann 03 July 2015 (has links) (PDF)
Much research was performed in order to find alternative energy sources. In the new concept presented in this thesis, methane was produced by a microbial consortium which is fed only by glycolate excreted by photosynthetic algae. It was unknown how the biogas production and the process stability are influenced by certain parameter shifts in glycolate feed, pH of the feed, oxygen input and temperature. Therefore, different parameter changes were applied to the reactor system. Gas formation and composition, pH, FosTac and organic acid content in the media were analyzed. Additionally, the community composition induced by the changes of the process parameters was analyzed. Therefore, the single cell level using flow cytometry and the genetic level using T-RFLP were observed. The R based tool flowCyBar was applied to follow community dynamics and to find key players in the process. Abiotic and biotic parameters were used for correlation analysis (Spearman´s Rho) to determine specific functions of sub-communities and the T-RFs found in the whole community. The cultivation at room temperature indicated that the biogas yield was 30 % lower in comparison to the cultivation at 37°C. The community seemed to be able to sustain pulsating oxygen input in case glycolate as substrate is available. Additionally, the system was able to recover after the oxygen application of one day. A linear correlation between the feed glycolate and the biogas production was observed (R^2 = 0.97). High biogas yields were obtained (up to 90 %) indicating that glycolate is a suitable substrate. The efficiency of the process was high with 41 ± 3 % methane in the biogas under defined conditions. It could be observed that biogas can be produced on glycolate as mono-substrate by a complex microbial community while it remained complex over the complete study (505 days cultivation) although glycolate was used as sole carbon source. Key sub-communities (e.g. cluster 1 and 3) and T-RFs (e.g. T-RF representing Planctomycetaceae or 67 bp) were defined and indicated the status of the bioreactor. The community was able to sustain certain parameter shifts, like changes in the pH of the feed (from 3 to 7), while others led to a complete crash of the system, like high glycolate feeds (3.6 g d^-1 L^-1). All in all, the stability of the process seemed to be susceptible on external influences.
20

Untersuchung gepulster laminarer rußender Methan-Luft-Diffusionsflammen unter erhöhtem Druck

Hentschel, Janbernd. January 2006 (has links)
Universiẗat, Diss., 2006--Karlsruhe.

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