2,501 research outputs found
Dynamics of space charge and electroluminescence modelling in polyethylene
No full textSpace charge has been recognized as an important factor contributing to the electrical failure of the cable insulation. Extensive efforts have been made to investigate space charge dynamics within polymeric insulations under electric stresses. Basic information about space charge has been recognized resorting to modern charge mapping techniques but the underlying mechanisms for charge transport, charge trapping characteristics are not yet well understood. Hence theoretical modelling and numerical simulation are employed to simulate the space charge and provide an insight into the charge distribution in dielectrics. This thesis comprises the quantitative analysis of space charge through numerical modelling and experimental investigations of charge trapping in polymeric insulation materials.A bipolar charge transport model which involves bipolar charge injection from the electrodes, charge transport with trapping and recombination in the bulk has been developed to simulate the dynamics of space charge in polyethylene. The build-up of space charge in polyethylene under dc electric fields has been modelled. The influence of parameters related to the properties of polyethylene on the formation of space charge has been recognized. Furthermore, this model is introduced to simulate the dynamics of corona charge decay in polyethylene. The formation of charge packets in polyethylene is also investigated using a numerical modelling approach.A fast pulsed electro-acoustic system along with a data processing program has been developed to investigate the behaviour of space charge in polyethylene under ac voltages. The understanding of space charge under ac stresses has also been simulated using the further developed bipolar charge transport model. Experiments and simulation have also been expanded into understanding electroluminescence, which is an indication of pre-aging of polymers under ac stress
Skin-Stiffener Separation in T-Stiffened Composite Specimens in Postbuckling Condition
No full textAn experimental and numerical investigation was conducted to study the skin-stiffener separation of single T-shape stiffener specimens in postbuckling condition. Three specimens were manufactured with a centrally located Teflon insert, and were loaded in compression until collapse. Deformation patterns and separation evolution were monitored during the tests. To measure the full-field displacements and the strain distributions of the specimens, a digital image correlation (DIC) system was used. Skin-stiffener separation was observed and measured with an ultrasound system. Finite-element (FE) analyses were conducted to capture interlaminar damage mechanism based on the virtual crack closure technique. The numerical analysis accurately predicted the postbuckling deformation and the skin-stiffener separation behavior. The close correlation between the experimental and numerical results allows for further exploitation of the strength reserve in the postbuckling region and wider design options for the next generation of composite aircraft designs.</p
Finite Element Methods and Their Convergence for Elliptic and Parabolic Interface Problems
No full textIn this paper, we consider the finite element methods for solving second order elliptic and parabolic interface problems in two-dimensional convex polygonal domains. Nearly the same optimal L 2 -norm and energy-norm error estimates as for regular problems are obtained when the interfaces are of arbitrary shape but are smooth, though the regularities of the solutions are low on the whole domain. The assumptions on the finite element triangulation are reasonable and practical. Mathematics Subject Classification (1991): 65N30, 65F10. A running title: Finite element methods for interface problems. Correspondence to: Dr. Jun Zou Email: [email protected] Fax: (852) 2603 5154 1 Institute of Mathematics, Academia Sinica, Beijing 100080, P.R. China. Email: [email protected]. The work of this author was partially supported by China National Natural Science Foundation. 2 Department of Mathematics, the Chinese University of Hong Kong, Shatin, N.T., Hong Kong. E-mail: [email protected]...
Hoe zou een publieke datadonatiepraktijk ten behoeve van gezondheid en welzijn eruit kunnen zien?
No full textDit boekje is verslag van het CHANGE! (Conscious Health dAta shariNg in movinG RottErdam!) project dat is uitgevoerd in 2021-22 in het kader van een Open Mind subsidie van het Convergence programma dat ten doel heeft samenwerking tussen TU Delft, Erasmus Universiteit Rotterdam en Erasmus Medisch Centrum te bespoedigen. Het stimuleert allianties van onderzoekers van de verschillende universiteiten om in samenwerking met publieke en private partners innovatieve bijdragen te leveren aan urgente en complexe maatschappelijke uitdagingen, zoals klimaatverandering, duurzaamheid, gezondheidszorg, verstedelijking en digitalisering.Dit (kleine, verkennende) interdisciplinaire project, uitgevoerd binnen het Health & Technology programma, betreft een onderzoek naar hoe een publieke datadonatiepraktijk ten behoeve van gezondheid en welzijn eruit zou kunnen zien. Het is een ultiem Convergence-project, omdat het grensoverschrijdend is voor elk van de participerende instituten en kennisdomeinen en expertise van het team. Binnen CHANGE! zijn onder andere de medische, ethische, sociaal-maatschappelijke, politieke en ruimtelijke (en niet strikt de technische) aspecten van het verzamelen en werken met gezondheidsdata verkend.Design Aesthetic
Wanted! Investigating how elements from the personal usage context affect Gen Z consumers' value-in-use experience and engagement with mobile service
No full textsponsorship: The research underlying this article has benefitted from a China Scholarship Council grant (No. 201508320285) to the first author. (China Scholarship Council|201508320285)status: Publishe
A contextual classification approach for forest land cover mapping using high spatial resolution multispectral satellite imagery – a case study in Lake Tahoe, California
No full textMaps of classified surface features are a key output from remote sensing. Conventional methods of pixel-based classification label each pixel independently by considering only a pixel’s spectral properties. While these purely spectral-based techniques may be applicable to many medium and coarse-scale remote sensing analyses, they may become less accurate when applied to high spatial resolution imagery in which the pixels are smaller than the objects to be classified. At this scale, there is a higher intra-class spectral heterogeneity. Detailed forest and vegetation classification is extremely challenging at this scale with both high intra-class spectral heterogeneity and inter-class spectral homogeneity. A solution to these issues is to take into account not only a pixel’s spectral characteristics but also its spatial characteristics into classification. In this study, we develop a generalizable contextualized classification approach for high spatial resolution image classification. We apply the proposed approach to map vegetation growth forms such as trees, shrubs, and herbs in a forested ecosystem in the Sierra Nevada Mountains.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-08-01The student, Yi Zou, accepted the attached license on 2015-07-17 at 13:20.The student, Yi Zou, submitted this Thesis for approval on 2015-07-17 at 13:27.This Thesis was approved for publication on 2015-07-20 at 13:48.DSpace SAF Submission Ingestion Package generated from Vireo submission #8535 on 2015-09-29 at 15:00:47Made available in DSpace on 2015-09-29T20:50:19Z (GMT). No. of bitstreams: 2
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Goniocotes rolandi Gustafsson & Tian & Zou 2021, new species
No full textGoniocotes rolandi new species (Figs 10–11, 13–15) Type host: Crossoptilon harmani Elwes, 1881 —Tibetan eared pheasant (Phasianidae). Type locality: Southeast Tibet, China. Diagnosis. Goniocotes rolandi new species is most similar to Goniocotes crossoptiloni Liu, 1990. These two species can be separated by the following characters: male tergopleurites V–VI with 1 tps on each side and tergopleurite VII without tps in G. crossoptiloni, but tergopleurite V with 2–4 tps on each side, tergopleurite VI with 1–2 tps on each side, and tergopleurite VII with 1–2 tps on each side in G. rolandi (Fig. 10); male sternite IV–V with 2 sts on each side in G. crossoptiloni, but with 3–4 sts on each side in G. rolandi (Fig. 10); head of G. rolandi (Figs 10–11) proportionately wider and with flatter frons, especially in female, than head of G. crossoptiloni; vulval margins more or less gently rounded in G. crossoptiloni, but with pronounced median bulge in G. rolandi (Fig. 13); male genitalia not illustrated in sufficient detail for G. crossoptiloni, but appear to have shorter parameres and broader mesosome than those of G. rolandi (Figs 14–15). Description. Both sexes. Head shape as in Fig. 10; temples flaring with definite postero-lateral corner at aperture of mts1. Marginal carina of moderate width, widening anteriorly (more obvious in male). Head chaetotaxy as in Figs 10–11; os sexually dimorphic; s1–2 and s5–9 present, as well as one sensillum situated roughly on a line between pts and pns, which may be either of s3–4. Thoracic and abdominal segments as in Figs 10–11. Reticulation covers almost all of tergal and subgenital plates, but is less distinct elsewhere. For clarity, we have here illustrated only parts of this reticulation in grey, to indicate the relative size of the cells in the pattern. Measurements as in Table 1. Male. Ocular seta macroseta (Fig. 10). Thoracic and abdominal chaetotaxy as in Fig. 10; median section of pteronotum with one macroseta and one microseta on each side; tergopleurites II–IV with setal rows; tergopleurite V with 2–4 tps on each side; tergopleurite VI with 1–2 tps on each side (one specimen with no tps on one side); tergopleurite VII with one tps on each side. Basal apodeme long and slender (Figs 14–15). Mesosome present, roughly triangular dorsally (Fig. 14), but ventrally with distinct hook-shaped lateral extensions at about mid-length. One small sensillum on each side near the dorsal anterior margin; no other sensilla or setae visible. Postero-lateral corners of basal apodeme with rugose nodi; parameres slender and somewhat elongated. Female. Ocular seta microseta (Fig. 11). Thoracic and abdominal segments and chaetotaxy as in Fig. 11. Vulval margin with distinct median bulge and lateral sections deeply concave (Fig. 13). Vulval chaetotaxy: 41–48 long, slender vms (often in double rows at least laterally) and 2–3 large, thorn-like vss on each side; oblique set with 5–8 vos of varying length on each side, typically with distal setae longer than more proximal setae. Etymology: The specific epithet is in honour of the first author’s father, Roland Gustafsson, who spent many weekends taking him outdoors to watch birds, to camp, to enjoy nature, and introducing him to his first bird-ringing event outside Jönköping, Sweden, in the early 1990s. This laid the foundations of a solid interest in nature for the first author, who eventually devoted his life to biological research. Type material. Ex Crossoptilon harmani: Holotype ♂, S.E. Tibet [China], May 1912, R. Meinertzhagen, ID 3759, NHMUK010675935 [right-most male on slide, marked with black dot] (NHMUK). Paratypes. 3♂, 6♀, same data as holotype, NHMUK010675934–5 (NHMUK).Published as part of Gustafsson, Daniel R., Tian, Chunpo & Zou, Fasheng, 2021, New species of ischnoceran chewing lice (Phthiraptera: Philopteridae) from Chinese birds, pp. 305-328 in Zootaxa 4990 (2) on pages 310-317, DOI: 10.11646/zootaxa.4990.2.6, http://zenodo.org/record/502655
Electronic health records and improved nursing management of chronic obstructive pulmonary disease [Corrigendum]
No full textLiu F, Zou Y, Huang Q, Zheng L, Wang W. Patient Preference and Adherence. 2015;9:495–500.On page 495, author affiliations and correspondence sections “The First Affiliated College of Medicine, Zhejiang University” should be “The First Affiliated Hospital, College of Medicine, Zhejiang University”.Read the original articl
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