7,395 research outputs found
Scaling of solar wind e and the AU, AL and AE indices as seen by WIND
No full textWe apply the finite size scaling technique to quantify the statistical properties of fluctuations in AU, AL and AE indices and in the parameter that represents energy input from the solar wind into the magnetosphere. We find that the exponents needed to rescale the probability density functions (PDF) of the fluctuations are the same to within experimental error for all four quantities. This self-similarity persists for time scales up to ~4 hours for AU, AL and and up to ~2 hours for AE. Fluctuations on shorter time scales than these are found to have similar long-tailed (leptokurtic) PDF, consistent with an underlying turbulent process. These quantitative and model-independent results place important constraints on models for the coupled solar wind-magnetosphere system
aE Journal 2015/2016: aE/INTECTURE innovating architecture
No full textThe graduation studio of Architectural Engineering focuses on the integration of (new) technology in architecture. For this purpose, the name aE/ INTECTURE® was devised, which will be developed further as a brand in the coming years. Students start with a technical fascination and translate this into an architectural concept, finally being able to implement this within the environment in a responsible way. ‘If technology is the answer, what is the question?‘ Under the guidance of a team of enthusiastic (guest) lecturers, students search for the dot on the horizon that is necessary for coming up with solutions that improve the quality of the built environment and make it more sustainable. In addition, either the ‘making‘ (make) or ‘the energy and material flow’ (flow) is used and applied as a basis in different contexts.Architectural Engineerin
Stability of the cubic phase in GaN doped with 3d-transition metal ions
No full textWe investigate the stability of the zinc-blende (ZB) phase in GaN doped with transition metal ions using generalized-gradient approximation (GGA) calculations. The GGA calculations show that the ZB phase can be stabilized when the concentrations of the Cr and Mn ions are greater than 21% and 27% in GaCrN and GaMnN alloys, respectively. In GaFeN alloys, the stabilization of the ZB phase occurs at a much higher concentration of the Fe ions. If strong on-site Coulomb repulsion (U) is included, the ZB phase cannot be stabilized for all Fe concentrations. We also study the effects of electron and hole doping on the stability of the ZB phase in GaMnN alloys, and find that the critical concentration is reduced to 13% by doping one electron per Mn ion, while hole doping with a hole per Mn ion does not much affect the critical concentration. (C) 2007 Elsevier B.V. All rights reserved
Scaling in long term data sets of geomagnetic indices and solar wind ϵ as seen by WIND spacecraft
No full textWe study scaling in fluctuations of the geomagnetic indices (AE, AU, and AL) that provide a measure of magnetospheric activity and of the ε parameter which is a measure of the solar wind driver. Generalized structure function (GSF) analysis shows that fluctuations exhibit self-similar scaling up to about 1 hour for the AU index and about 2 hours for AL, AE and ε when the most extreme fluctuations over 10 standard deviations are excluded. The scaling exponents of the GSF are found to be similar for the three AE indices, and to differ significantly from that of ε. This is corroborated by direct comparison of their rescaled probability density functions
Structural health monitoring of adhesively-bonded hybrid joints by acoustic emission
No full textThe increasing use of Adhesively-bonded joints in industrial applications resulted in more attention to damage assessment in these joints. The aim of the present study is to characterize the damage in bi-material double-lap adhesively-bonded joints by Acoustic Emission (A E). Two different structural adhesives, representing a ductile (Methacrylate-based) and brittle (epoxy-based) types, were used to bond C F R P skins to a steel core. The fabricated joints were loaded in tension while damage evolution was monitored by A E . Due to the difference in the fracture nature of the adhesives "brittle vs. ductile", different damage mechanisms occurred in the specimens; including adhesive layer failure, steel deformation, adhesive/adherends interfacial debonding and delamination in the C F R P skin. In order to distinguish and classify these damage types by A E, the AE features of each damage mechanism were first obtained by conducting some standard tests on the individual constituent materials. Then, these AE reference patterns were used to train an ensemble decision tree classifier. Finally, the trained model classified the AE signals of the double-lap tests and the images captured by camera were utilized to verify AE results. This study demonstrates the potential of AE technique for damage characterization of the adhesively-bonded bi-material joints.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Structural Integrity & Composite
Energetics of cubic and hexagonal phases in Mn-doped GaN: First-principles pseudopotential calculations
No full textWe perform first-principles pseudopotential calculations to study the influence of Mn doping on the stability of two polytypes, wurtzite and zinc-blende, in GaN. In Mn delta-doped GaN and GaMnN alloys, we find similar critical concentrations of the Mn ions for stabilizing the zinc-blende phase against the wurtzite phase. Using a slab geometry of hexagonal lattices, we find that it is energetically unfavorable to form inversion domains with Mn exposure, in contrast to Mg doping. At the initial stage of epitaxial growth, a stacking fault that leads to the cubic bonds can be generated with the Mn exposure to the Ga-polar surface. However, the influence of the Mn delta-doped layer on the formation of the cubic phase is only effective for GaN layers deposited up to two monolayers. We find that the Mn ions are energetically more stable on the growth front than in the bulk, indicating that these ions act as a surfactant. Thus it is possible to grow cubic GaN if the Mn ions are periodically supplied or diffuse out from the Mn delta-doped layer to the growth front during the growth process.
aE Journal 2017/2018: aE/Intecture innovating architecture
No full textDriven by the need to think differently about resources, energy, power generation, the choice of materials, and user involvement, we see the built environment in a new perspective. The program, Architectural Engineering, seeks for innovative and inspiring architectural solutions for social and environmental issues throughout all scales.To achieve this, innovation of the architectural challenge is high on our agenda. Innovation is more than just a technical improvement. How do you implement new current issues in modern architecture? We anticipate new energy, materials, and circularity. We also use the current environment of the metropolis and the countryside. We add new buildings, strengthen existing stock, and work on new components of buildings. From high to low tech. From digital to traditional, looking carefully to the context.Architectural Engineerin
The effects of low temperatures on larval survival of Aedes aegypti and Ae. albopictus (Diptera: Culicidae) in Taiwan
No full text埃及斑蚊與白線斑蚊在台灣有不同的分布，前者侷限於台灣的南部，後者則是全省都有分布。往昔研究認為冬季的氣溫可能是影響分布的因子之一。本實驗有三個部分，第一部分為實驗室內的試驗，我將埃及斑蚊與白線斑蚊的一齡及四齡幼蟲在低溫下處理不同時間，並以處理時間和存活率之間的線性迴歸來估算50%致死時間 (LT50)。結果發現，在一齡幼蟲中，白線斑蚊在2.5，5 及10oC的處理後均比埃及斑蚊有較高的存活率。白線斑蚊一齡幼蟲在10oC的50%致死時間長達526 小時，是埃及斑蚊一齡幼蟲的五倍長。在四齡幼蟲中，埃及斑蚊在2.5 及5oC的處理後存活率比白線斑蚊稍高，而白線斑蚊則是在10oC的處理後有較高的存活率。第二部分將一齡幼蟲在5oC下作四個世代的篩選，結果顯示兩種蚊子的耐寒能力均有增加。第三部分為田間試驗，於2004 年十二月底至2005 年四月將埃及斑蚊與白線斑蚊的一齡幼蟲飼育於自然環境中直到全部羽化或死亡，結果發現在有寒流來襲的月分中，白線斑蚊有較高的存活率。根據本實驗的結果推測，北台灣冬季的溫度對於埃及斑蚊的分布是一個可能的影響因子。Aedes aegypti and Ae. albopictus differ in their distribution in Taiwan. The former species is distributed only in the south of Taiwan while the latter is found island-wide. One of the possible explanations proposed is that low temperature in winter to prevent the colonization by Ae. aegypti. Hence, the impact of low temperatures on immatures of both species is studied here in the laboratory
and field. In laboratory experiments, first and fourth instar larvae were exposed to low temperatures for various times. I estimated the lethal time that could kill 50% of populations (LT50) using linear regression. For the first instar larvae, Ae. albopictus was more tolerant than Ae. aegypti at temperatures of 2.5, 5 and 10oC. First instar larvae of Ae. albopictus showed remarkable tolerance at 10oC and the LT50 was estimated to be 526 hours, which is five times to that of Ae. aegypti. For fourth instars, Ae.aegypti had greater tolerance than Ae. albopictus at 2.5 and 5oC, but Ae. albopictus had a greater tolerance at 10oC. First instars were selected at 5oC over four generations. Both species showed more tolerance after selection. Aedes aegypti showed a greater mortality than Ae. albopictus during exposure to cold fronts but the opposite was true in the absence of a cold front. The lethal effect of cold fronts on Ae. aegypti was identified from their daily mortality. My studies suggest that winter temperature in the north part of Taiwan may have a significant effect on the distribution of Ae. aegypti in Taiwan.Introduction 1
Materials and Methods 3
Results 8
Discussion 11
References cited 16
Acknowledgements 19
Tables 20
Figures 2
Main motifs in the prose of the leftist author Kang Kyŏng-ae
No full textThe subject of this bachelor thesis is the life and work of the Korean writer Kang Kyǒng-ae, with a focus on her short prose. The aim of this thesis is an analysis of two works - Salt and Darkness - with attention to the context of the author's time. Nowadays, Kang Kyǒng-ae is considered a significant author of the 1930s and her works reflect the phenomenon of Korean emigrants in Manchuria. For a long time, leftist tendencies caused her prose to be neglected, which resulted in a considerably limited number of studies concerned with her work, in comparison to the number of studies about other writers. There are virtually no Czech studies of her work. The text of the thesis initially presents the timeframe of Kang's authorship and then analyzes select works of hers. The analysis of the works focuses on recurring motifs, which are put into a historical and social context. Keywords Kang Kyǒng-ae, Korean 1930s literature, leftist literature, Sogǔm, Ǒdu
Larynx-Preserving Partial Pharyngectomy via Lateral Pharyngotomy for the Treatment of Small (T) Hypopharyngeal Squamous Cell Carcinoma
No full textObjectivesTo evaluate the oncologic and functional results of larynx-preserving partial pharyngectomy (LPP) via lateral pharyngotomy approach as a primary treatment for small (T1 or T2) hypopharyngeal squamous cell carcinoma (HPSCC).MethodsWe performed a retrospective review of 23 patients who underwent LPP through lateral pharyngotomy approach for small HPSCC at the our department between January 1991 and June 2007. Fourteen (61%) patients had adjuvant postoperative radiotherapy.ResultsThe 2-years and 5-years disease specific survival rate was 77% and 61%, respectively. Nine patients (39%) had tumor recurrence. The most common pattern of recurrence was isolated distant failure (n=4, 44%) followed by local (n=2, 22%) and loco-regional (n=3, 34%) recurrence. The ultimate cure rate of the primary tumor was 87% (20 of 23). Twenty-two of the 23 patients (95%) could be decannulated, tolerate an oral diet, and had acceptable postoperative phonatory function.ConclusionLPP via lateral pharyngotomy approach appears to be a feasible procedure for selected small HPSCC patients in terms of both oncologic and functional outcomes
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