scholarly journals Mesophilic Fermentation of Renewable Biomass: Does Hydraulic Retention Time Regulate Methanogen Diversity?

2010 ◽  
Vol 76 (18) ◽  
pp. 6322-6326 ◽  
Author(s):  
Niclas Krakat ◽  
Stefan Schmidt ◽  
Paul Scherer
Keyword(s):  
Ribosomal Rna ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Restriction Analysis ◽  
Term Study ◽  
Renewable Biomass ◽  
Long Term Study ◽  
Gene Restriction

ABSTRACT The present long-term study (about 1,100 days) monitored the diversity of methanogens during the mesophilic, anaerobic digestion of beet silage. Six fermentor samples were analyzed by ribosomal RNA gene restriction analysis, fluorescence in situ hybridization, and fluorescence microscopy. Hydrogenotrophic methanogens dominated within the population in all samples analyzed. Multidimensional scaling revealed that a rapid decrease in hydraulic retention time resulted in increased species richness, which in turn led to slightly higher CH4 yields.

scholarly journals Anaerobic Digestion of Renewable Biomass: Thermophilic Temperature Governs Methanogen Population Dynamics

2010 ◽  
Vol 76 (6) ◽  
pp. 1842-1850 ◽  
Author(s):  
Niclas Krakat ◽  
A. Westphal ◽  
S. Schmidt ◽  
P. Scherer
Keyword(s):  
Anaerobic Digestion ◽  
Fluorescence Microscopy ◽  
Restriction Analysis ◽  
Rrna Gene ◽  
Temperature Dependent ◽  
Renewable Biomass ◽  
Operational Taxonomic Units ◽  
Methanogen Population ◽  
Gene Restriction

ABSTRACT Beet silage and beet juice were digested continuously as representative energy crops in a thermophilic biogas fermentor for more than 7 years. Fluorescence microscopy of 15 samples covering a period of 650 days revealed that a decrease in temperature from 60°C to 55°C converted a morphologically uniform archaeal population (rods) into a population of methanogens exhibiting different cellular morphologies (rods and coccoid cells). A subsequent temperature increase back to 60°C reestablished the uniform morphology of methanogens observed in the previous 60°C period. In order to verify these observations, representative samples were investigated by amplified rRNA gene restriction analysis (ARDRA) and fluorescence in situ hybridization (FISH). Both methods confirmed the temperature-dependent population shift observed by fluorescence microscopy. Moreover, all samples investigated demonstrated that hydrogenotrophic Methanobacteriales dominated in the fermentor, as 29 of 34 identified operational taxonomic units (OTUs) were assigned to this order. This apparent discrimination of acetoclastic methanogens contradicts common models for anaerobic digestion processes, such as anaerobic digestion model 1 (ADM1), which describes the acetotrophic Euryarchaeota as predominant organisms.

From Collaborative Habituation to Everyday Togetherness: A Long-Term Study of Use of the Messaging Kettle

2022 ◽  
Vol 29 (1) ◽  
pp. 1-47
Author(s):  
Aloha Hufana Ambe ◽  
Alessandro Soro ◽  
Daniel Johnson ◽  
Margot Brereton
Keyword(s):  
Adult Daughters ◽  
Term Study ◽  
Older Mothers ◽  
Long Term Study ◽  
Everyday Practices ◽  
The Social ◽  
Gradual Transformation ◽  
Ageing Populations

We present a long-term study of use of the Messaging Kettle, an Internet of Things (IOT) research prototype that augments an everyday kettle with both sensing and messaging capability and a beautiful light display in order to investigate connecting geographically distant loved ones to their family through the routine of boiling the kettle. Connection at a distance has been of sustained interest to the CHI community, and the social connection of older people is of increasing importance in recognition of ageing populations globally. However, very few novel designs in this domain have been investigated in situ or over the long term to examine whether their use sustains, and if so, how they impact communication in a relationship. The Messaging Kettle was trialled with four pairs of dispersed older mothers and adult daughters over timeframes that lasted between two months to more than two years. We observed the phenomenon of collaborative habituation wherein each party creatively made the technology work for them both through a combination of the gradual transformation of their everyday practices, arrangements, and living. Through developing these joint practices over time, participants expressed feelings of everyday togetherness that nurture their relationship at a distance. Three of the four couples continued to use the prototype for years, beyond the initial trial. We reflect on the artful integration of features of the Messaging Kettle and the way in which these features supported collaborative habituation . We also reflect on lessons and implications for the design of such relational technologies.

scholarly journals Thermally induced movements in ice-wedge polygons, western arctic coast: a long-term study

2002 ◽  
Vol 54 (1) ◽  
pp. 41-68 ◽  
Author(s):  
J. Ross MacKay
Keyword(s):  
Active Layer ◽  
Term Study ◽  
Thermally Induced ◽  
Seasonal Movements ◽  
Long Term Study ◽  
Ice Wedge ◽  
Western Arctic ◽  
Arctic Coast

AbstractThermally induced seasonal movements of the active layer and subjacent permafrost have been measured in numerous ice-wedge polygons that have varied in age, type, crack frequency, and topographic location. The field observations show that, in winter, thermal contraction, which is inward, is constrained or vanishes at the polygon centres but, in summer, thermal expansion, which is outward, is unconstrained at the ice-wedge troughs. Therefore, there tends to be a small net summer transport of the active layer, to varying depths, into the ice-wedge troughs. The movement has been observed in all polygons studied. The slow net transport of material into the ice-wedge troughs has implications for: permafrost aggradation and the growth of syngenetic wedges in some troughs; the palaeoclimatic reconstruction of some ice- wedge casts; and the interpretation of polygon stratigraphy based upon the assumption that the polygon material has accumulatedin situ.

Long term study of the effectiveness of in-situ chemical source clean with XeF[sub 2] on ion implanter

2012 ◽  
Author(s):  
Dieter Fuchs ◽  
Klaus Kerkel ◽  
Josef Vogl ◽  
Michael Dorozynskyj
Keyword(s):  
Term Study ◽  
Long Term Study

scholarly journals Corneal ectasia after myopic laser in situ keratomileusis: a long-term study

2012 ◽  
pp. 1801 ◽  
Author(s):  
Leopoldo Spadea ◽  
Cantera ◽  
Cortes ◽  
Evangelista Conocchia ◽  
Stewart
Keyword(s):  
Laser In Situ Keratomileusis ◽  
Term Study ◽  
Corneal Ectasia ◽  
Long Term Study

The Medieval Town of Óbidos (Portugal): Restoration, Reutilisation and Tourism Challenges from 1934 to the Present Day

Heritage ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 2876-2902
Author(s):  
Clara Moura Soares ◽  
Maria João Neto
Keyword(s):  
In Situ Observation ◽  
Term Study ◽  
Long Term Study ◽  
History Of ◽  
Historic Centre ◽  
The Common ◽  
Artistic Heritage ◽  
The Town

Heritage conservation and cultural tourism are central features of academic debates, as this relationship has not been always peaceful. This paper seeks to evaluate the correlation between the extensive conservation and restoration of the wall and castle of the medieval town of Óbidos (1930–1950) and the tourism-oriented projects developed since this period. Due to the criticism of several previous studies, one of the primary aims of this research was to assess whether this Portuguese town constitutes a good example of medieval reconstitution, or if it is a fanciful twentieth-century intervention. Another main goal was to establish our position regarding the challenges inherent to the management of this historic centre, especially those concerning current tourism challenges and the preservation of and regard for historical buildings and monuments. By means of a long-term study based on the common history of art methodology (cross-analysis of bibliography, archival research, in situ observation of the heritage and attendance of festivals and events), we were able to make the following contributions to advance the debate: although the earlier interventions in Óbidos abided by strict criteria which merited international praise, the management model of the town as a tourist destination over the last two decades calls for a revaluation, placing greater importance on history, historic and artistic heritage and the identity of the location.

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