11. Designing new renewable nano-structured electrode and membrane materials for direct alkaline ethanol fuel cell : Information on catalytic activity, structure and electric current con- ductivity of new catalysts on supporting substratesEgon Pavlica, Gvido Bratina, Jørgen Svendby, Qingjun Chen, Jia Yang, De Chen, Ji-Song Huang, Jessie Lue Shingjiang, 2020, final research report Keywords: fuel cell, ethanol oxidation, graphene, oxygen reduction, catalyst, pt-free, electrochemical impedance spectroscopy
Published in RUNG: 03.12.2020; Views: 4328; Downloads: 0
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12. On the GeV Emission of the Type I BdHN GRB 130427ARemo Ruffini, Rahim Moradi, Jorge Armando Rueda, Carlo Luciano Bianco, Christian Cherubini, Simonetta Filippi, Yen-Chen Chen, Mile Karlica, Narek Sahakyan, Yu Wang, She Sheng Xue, Laura Beccera, 2019, original scientific article Abstract: We propose that the inner engine of a type I binary-driven hypernova (BdHN) is composed of Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B_0 aligned with the BH rotation axis and surrounded by an ionized plasma of extremely low density of 10^−14 g cm−3. Using GRB 130427A as a prototype, we show that this inner engine acts in a sequence of elementary impulses. Electrons accelerate to ultrarelativistic energy near the BH horizon, propagating along the polar axis, θ = 0, where they can reach energies of ~10^18 eV, partially contributing to ultrahigh-energy cosmic rays. When propagating with $\theta \ne 0$ through the magnetic field B_0, they produce GeV and TeV radiation through synchroton emission. The mass of BH, M = 2.31M ⊙, its spin, α = 0.47, and the value of magnetic field B_0 = 3.48 × 10^10 G, are determined self consistently to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy ${ \mathcal E }\sim {10}^{37}$ erg is ~10^−14 s at the beginning of the process, then slowly increases with time evolution. In principle, this "inner engine" can operate in a gamma-ray burst (GRB) for thousands of years. By scaling the BH mass and the magnetic field, the same inner engine can describe active galactic nuclei.
Keywords: black hole physics, binaries, gamma-ray burst, neutron stars, supernovae, Astrophysics - High Energy Astrophysical Phenomena
Published in RUNG: 20.07.2020; Views: 4129; Downloads: 0
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13. Uranium bearing dissolved organic matter in the porewaters of uranium contaminated lake sedimentsBreda Novotnik, Wei Chen, R. Douglas Evans, 2018, original scientific article Abstract: Uranium (U) mobility in the environment strongly depends on its oxidation state and the presence of complexing
agents such as inorganic carbon, phosphates, and dissolved organic matter (DOM). Despite the importance of
DOM in U mobility, the exact mechanism is still poorly understood. Therefore, the aim of our investigation was
to characterise sediment porewater DOM in two lakes in Ontario, Canada (Bow and Bentley Lakes) that were
historically contaminated with U and propose possible composition of UO2-bearing DOM. Depth profiles of U
concentrations in porewaters and total sediment digests reveal U levels of up to 1.3 mg L−1 in porewater and up
to 0.8 mg−1 g in sediment. Depth profiles of U did not correlate with Fe, Mn, SO4
2−, or Eh profiles. Therefore,
porewater DOM was analysed and taken into consideration as the primary source of U mobility. Porewater DOM
in each sediment section (1 cm sections, 20 cm core length) was analysed by high-resolution electrospray ionisation
mass spectrometry. PCA analyses of porewater DOM mass spectra showed grouping and clear separation
of DOM in sediment sections with elevated U concentrations in comparison to sections with background U
concentrations. Several criteria were set to characterise UO2-bearing DOM and more than 70 different molecules
were found. The vast majority of these UO2-DOM compounds fell in the category of carboxyl-containing aliphatic
molecules (H/C between 0.85 and 1.2 and O/C≤0.4) and had a mean value of m/z about 720.
Keywords: Uranium
Lake sediments
Porewater
Disolved organic matter
High resolution mass spectrometry
Published in RUNG: 09.10.2019; Views: 4443; Downloads: 0
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14. Properties of tropospheric aerosols observed over southwest SloveniaTingyao He, Yingying Chen, Samo Stanič, Klemen Bergant, Fei Gao, Dengxin Hua, 2018, original scientific article Abstract: From August to October 2010 lidar measurements of aerosols in the troposphere were performed at Otlica observatory, Slovenia, using a vertical scanning elastic lidar. The lidar data sample, which contains 38 nighttime vertical profiles of the mean aerosol extinction, was combined with continuous ozone concen- tration (O3), particulate matter concentrations (PM) and daily radiosonde data. The obtained radiosonde- and lidar-derived heights of the atmospheric boundary layer (ABL), which varied considerably from day to day, were found to be in good agreement. The mean values of the aerosol optical depth (AOD) at 355 nm, were calculated separately for the ABL and for the free troposphere (FT). A ten-fold increase of the FT AOD was observed during the days with predicted presence of Saharan dust above the lidar site. To correlate AOD values with the type and origin of aerosols, backward trajectories of air-masses above Otlica were modeled using the HYSPLIT model and clustered. High ABL AOD values were found to be correlated with local circulations and slowly approaching air masses from the Balkans and low values with northwestern flows. The highest values correlated with southwestern flows originating in northern Africa.
Keywords: Aerosol, Optical depth, Lidar, Atmospheric boundary layer
Published in RUNG: 22.02.2019; Views: 5145; Downloads: 0
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15. Urban Conservation System in China and Its Improvement by Using Historic Urban Landscape ApproachChen Shujie, 2018, doctoral dissertation Abstract: In the last few decades, the Modern Conservation Movement has developed from European-limited practices into a global movement with universal common views and practical measures for managing heritage resources in different cultural contexts. As an innovative idea of this movement, the Historic Urban Landscape approach aims to protect and manage historic urban environments with respect to both the fundamental principles in the international doctrines and the local social/cultural/historical contexts. It recommends local authorities to use the HUL toolkit to identify, conserve and manage the overall landscape of their historic cities.
In the case of China, who is an old civilization, a modern nation and a socialist country at the same time, the conservation practice needs to follow the basic and common conservation principles in the international doctrines, and meanwhile, it shall make its initiatives based on the actual social, cultural and political situations. The establishment of Historically and Culturally Famous City (HCF City in short) system is a positive attempt for such a purpose. The system manages various urban elements relating to the city’s historical and cultural features under a comprehensive notion of HCF City. However, the system is not prefect because it depends excessively on the top-down management of local governments, and also because it overlooks the spatial and spiritual relationships among the protected elements...
The thesis provides a big picture of architectural and urban conservation practices in China. It introduces the forming process and the characteristics of historic urban fabric, as well as the history of urban conservation. Then, it takes a deep look at the existing HCF City system, including its basic ideas, structures and mechanism. It analyses the system’s initiatives and deficiencies. Finally, it provides feasible advices to improve the current system by using the HUL toolkit.
Keywords: Urban, History, Heritage, Conservation, Management International Principles, Modern Conservation Movement, Globalization, Localization Historic Urban Area, Historically and Culturally Famous Cities, Conservation System, Historic Urban Landscape Chinese Architecture, Chinese Urban Planning, Conservation History, Policy
Published in RUNG: 11.02.2019; Views: 7214; Downloads: 83
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16. Polymer Vesicles with a Colloidal Armor of NanoparticlesRong Chen, Daniel J. G. Pearce, Sara Fortuna, David L. Cheung, Stefan A. F. Bon, 2011, original scientific article Abstract: The fabrication of polymer vesicles with a colloidal armor made from a variety of nanoparticles is demonstrated. In addition, it is shown that the armored supracolloidal structure can be postmodified through film-formation of soft polymer latex particles on the surface of the polymersome, hereby effectively wrapping the polymersome in a plastic bag, as well as through formation of a hydrogel by disintegrating an assembled polymer latex made from poly(ethyl acrylate-co-methacrylic acid) upon increasing the pH. Furthermore, ordering and packing patterns are briefly addressed with the aid of Monte Carlo simulations, including patterns observed when polymersomes are exposed to a binary mixture of colloids of different size.
Keywords: Pickering emultion, self-assemblt, Monte Carlo, simulation, nanoparticle, packing, pattern garnd canonical, colloids
Published in RUNG: 11.10.2016; Views: 5975; Downloads: 0
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