Order-disorder in Natural Nepheline Solid Solutions

The variation of the birefringence with temperature, from roomtemperature up to c. 900? C, was studied of 34 nephelines fromdifferent geological environments. The measurements were madewith a Berek compensator using a microscope heating stage. Two optical types of nepheline were distinguished on the basisof the absolute value for birefringence at room temperatureand on the basis of the optical -value defined as >=(w-E)₉₀₀?-(w-E)₂₀?.The optical type I is characterized by a high birefringenceat room temperature and by a highly negative optical -value,whereas the optical type II shows a low birefringence at roomtemperature and a highly positive optical -value. The nephelinespecimens studied represent optically a continuous gradationfrom type I to type IL Both optical types are represented amongmediopotassic and perpotassic nephelines. A nepheline of the optical type I is considered to representthe ordered form of the mineral and a nepheline of the opticaltype II the disordered form. All plutonic nephelines studiedbelong to the optical type I whereas the volcanic nephelinesrange from the type I to the type II. Using a high temperature attachment for the Norelco diffractometer,the thermal expansion was measured of a few nepheline specimens.A nepheline belonging to the optical type I differs slightlyin thermal expansion from that of the optical type 11. Thisdifference in thermal expansion may qualitatively explain thedifference between the two optical types. The crystal structural nature of the supposed order-disordertransition in nepheline is not known. The analogy with the feldsparswould suggest a varying degree of ordering in the distributionof the silicon and aluminium cations in the oxygen tetrahedra.     

Commodification and the selling of ethnic music to tourists

The commodification of culture has received much attention in social and cultural geography. Based on empirical research in Lijiang, a World Heritage site in China, this paper contributes to an understanding of commodification through a focus on selling ethnic music to tourists. Drawing upon a theoretical framework of tourism commodification and the cultural politics of music, I argue that the commodification of music is embedded in a temporal process in which culture, economy, and politics synthesize to shape place making and identity building. This paper presents three major findings: (1) commodification sustains discourses of identity building and cultural revival that in turn serve to justify the pursuit of profit; (2) commodification is variegated over time and across space; and (3) commodification provides the conditions for local musicians to increase their capacity to produce local narratives of music. By demonstrating the commodification of ethnic music and the cultural politics of musical space in Lijiang, this paper calls for an interconnection of economy, culture, and politics in understanding the materiality of music.     

Monitoring near-surface soil freeze–thaw cycles in northern China and Mongolia from 1998 to 2007

Remote sensing based near-surface soil freeze–thaw cycles detection in middle latitude especially where near-surface changing seriously still rare. In this research, soil temperature and 7-day maximum/minimum combined passive microwave brightness temperature were employed to apply a soil freeze–thaw algorithm in northern China and Mongolia. We proposed a random sampling technique to determine brightness temperature thresholds for 37 GHz vertically polarized radiation: 258.2 and 260.1 K for the morning and evening satellite passes, respectively, and determined the onset, offset, and duration of the phases of the near-surface soil freeze–thaw cycle. During the 10 years from 1998 to 2007, the onset and offset of soil frozen/thawed in spring and autumn progressed from south to north and northwest, and from low elevation to high elevation. The durations of the freeze–thaw transitions in spring, autumn and whole year were longest in the Loess Plateau, Ordos Plateau, and Songnen Plain, where they were 1–3 weeks longer than in other regions. The total annual durations of soil frozen/thawed increased/decreased progressively from the south to both the northwest and northeast. Over the 10 years, changes to both the timing and duration of phases of the freeze–thaw cycle were greater in spring than in autumn. Most of the changes were less than 2 weeks, but there were changes of up to 3–4 weeks on the Northeast Plain, Loess Plateau, and at Mt. Yinshan. Our research has contributed to understanding near-surface earth systems and suggests that changes in earth surface may cause extreme environmental events such as the dust emission in semi-arid and arid regions of East Asia.     

Brown earth and podzol: soil genesis illuminated by microfossil analysis

Andersen, S. Th. 1979 03 01: Brown earth and podzol: soil genesis illuminated by microfossil analysis. Boreas , Vol. 8, pp. 59–73. Oslo. ISSN 0300–9483.
Pollen and other plant microfossils were studied in soil profiles from a Fagus-Quercus petraea woodland in eastern Jutland, Denmark. Fungal hypha fragments in the soil show characteristic length frequency distributions, which indicate comminution by large arthropods and microarthropods (Oribatei) during the burial. Distribution of the hypha fragments within the podzol indicates development from a former brown earth. The pollen sequence in a humus deposit reflects recent vegetational development. Modification of pollen assemblages in the mineral soils can be explained by mixing during burial by soil fauna. Development from brown earth to podzoloid and podzol follows the models assumed by pedologists. The various stages are related to vegetational changes and the processes were completed within a few hundred years.     

A comparative analysis of compositional variations in and between marine ferromanganese nodules and crusts in the South Pacific and their environmental controls

Regional variation of Mn, Fe, Co, Ni and Cu in ferromanganese oxides (nodules and crusts) in the central south Pacific is related to primary productivity, oxygen minimum layer, and calcium carbonate compensation depth. The largely latitudinal influence of these environmental parameters on nodule and crust composition reflects their predominantly latitudinal variation. Primary productivity is the principal regional environmental control, influencing diagenetic enrichment of these elements in nodules through its effect, mediated by the CCD, on supply and concentration of labile organic matter vs. carbonate remains to the sediments. It influences hydrogenetic enrichment of these elements in nodules and crusts through its effect, mediated by the oxygen minimum layer (mainly in the case of crusts), on their export from surface waters.The elements’ varying susceptibility to being scavenged or organically bound influences the contrasting composition of diagenetic vs. hydrogenetic ferromanganese oxides, which is further influenced by depth. Hydrogenesis is the fundamental process governing nodule and crust formation, superimposed on which is diagenesis under specific circumstances; both are subject to intermittent interruption, diminution and augmentation by changes in environmental parameters. Application of regionally operative environmental controls locally explains local compositional variations and helps refine exploration criteria for economically viable nodules and crusts.     

Parametric study on offshore jacket launching

Platform structures are commonly utilized for various purposes including offshore drilling, processing and support of offshore operations. Jacket type structures are attractive in relatively shallow water regions. A jacket is a supporting structure for deck facilities stabilized by leg piles through the seabed. The size of a jacket is dependent on deck size, pile dimensions and environmental loads. In a jacket design, operational and environmental loads are very important and must be investigated intensively to secure the stability of structures during their operation life, and installation phase as well. To confirm the stability, several analyses including in-place, fatigue, dynamic, load-out, transportation, lifting, and launching are performed. As the jacket weight and dimensions become large, a launching technique is applied to install the jacket. The launching analysis needs to consider quite a number of parameters including environmental conditions, launch barge specification, ballast, trim angle, local member integrity, etc. Due to the complexity of the operation, there is not a straightforward guideline or procedure for analysis. In this paper, a general procedure for analysis with various conditions and launching criteria are discussed and investigated. The effects of parameters are closely examined by numerical modeling.     

Building the ‘competitive city’: labour and Toronto’s bid to host the Olympic games

Toronto’s quest to host the Summer Olympic Games has dominated both contemporary planning discourse and practice. For some, the pursuit of the games embodies Toronto’s transformation into a ‘competitive’ global city. Relatively unexplored in this discourse are the contradictory roles that labour plays in contemporary urban development. I argue that the new labour geography can provide some interesting insights into such processes. Specifically, labour geographers have given workers with divergent interests greater agency in shaping economic landscapes and have noted the multi-scalar organisation of labour. The paper looks at the contradictory and conflicting positions held by different labour unions in Toronto toward the city’s bid to host the 2008 Olympics. The case study suggests that labour is an active agent in processes shaping contemporary Toronto and support the bid for complex reasons ranging from the promise of jobs to potential future organising opportunities.     

Developing an Erosion Risk Map Using Soft Computing Methods (Case Study at Sifnos Island)

The erosional processes depend on various variables such as lithology, topography,drainage system, rock structure and climatic conditions. The quantitative evaluationof some of the above geological and geomorphological parameters is of primaryimportance for the purpose of developing erosion risk maps. These maps can becomeuseful tools for developing appropriate strategies on environmental protection, hazardassessment and regional planning.The island of Sifnos, in Cyclades, was chosen as a case study, where in the final map of the sub-basins of this island, erosion risk distribution is presented.     

The importance of ocean temperature to global biogeochemistry

Variations in the mean temperature of the ocean, on time scales from millennial to millions of years, in the past and projected for the future, are large enough to impact the geochemistry of the carbon, oxygen, and methane geochemical systems. In each system, the time scale of the temperature perturbation is key. On time frames of 1-100 ky, atmospheric CO₂ is controlled by the ocean. CO₂ temperature-dependent solubility and greenhouse forcing combine to create an amplifying feedback with ocean temperature; the CaCO₃ cycle increases this effect somewhat on time scales longer than ∼5-10 ky. The CO₂/T feedback can be seen in the climate record from Vostok, and a model including the temperature feedback predicts that 10% of the fossil fuel CO₂ will reside in the atmosphere for longer than 100 ky. Timing is important for oxygen, as well; the atmosphere controls the ocean on short time scales, but ocean anoxia controls atmospheric pO₂ on million-year time scales and longer. Warming the ocean to Cretaceous temperatures might eventually increase pO₂ by approximately 25%, in the absence of other perturbations. The response of methane clathrate to climate change in the coming century will probably be small, but on longer time scales of 1-10 ky, there may be a positive feedback with ocean temperature, amplifying the long-term climate impact of anthropogenic CO₂ release.