200 research outputs found
Kompozithuzallal erĆsĂtett alumĂnium duplakompozit szerkezetek
A cikkben tĂĄrgyalt kerĂĄmia- Ă©s karbonszĂĄl-erĆsĂtĂ©sƱ, alumĂnium
mĂĄtrixĂș kompozithuzalok 0,1â2,5 mm ĂĄtmĂ©rĆvel Ă©s
60 tĂ©rfogat-%-nak megfelelĆ szĂĄlerĆsĂtĂ©ssel kĂ©szĂŒlnek. A
nedvesĂtĂ©s tökĂ©letesĂtĂ©sĂ©re szolgĂĄlĂł CVD vagy galvanikus
szĂĄlelĆkezelĂ©s is rĂ©sze a gyĂĄrtĂĄsi technolĂłgiĂĄnak. A nagy
gyĂĄrtĂĄsi sebessĂ©gnek köszönhetĆen az olvadĂ©k/szĂĄl hatĂĄrfelĂŒleti
reakciók lényegesen csökkentek, és ez kivåló mechanikai
tulajdonsĂĄgokat eredmĂ©nyezett. A folyamatos gyĂĄrtĂĄsĂș
kompozithuzalok kivĂĄlĂłan alkalmazhatĂłk arra, hogy
megkönnyĂtsĂ©k az alumĂniumöntvĂ©nyekbe törtĂ©nĆ erĆsĂtĆszĂĄl-
bevezetést, valamint duplakompozit szerkezetek (DC),
szendvicsszerkezetek Ă©s Ășn. kedvezĆen megerĆsĂtett szerkezeteket
gyĂĄrtĂĄsĂĄt. A mechanikai vizsgĂĄlatok azt mutatjĂĄk,
hogy a kompozithuzalokkal erĆsĂtett szerkezetek sokkal nagyobb
teherbĂrĂĄsĂșak, mint a szĂĄlakkal direkt mĂłdon erĆsĂtett
szerkezetek, vagy a bĂĄrmely erĆsĂtĂ©s nĂ©lkĂŒliek
PredDiff: Explanations and Interactions from Conditional Expectations
PredDiff is a model-agnostic, local attribution method that is firmly rooted
in probability theory. Its simple intuition is to measure prediction changes
while marginalizing features. In this work, we clarify properties of PredDiff
and its connection to Shapley values. We stress important differences between
classification and regression, which require a specific treatment within both
formalisms. We extend PredDiff by introducing a new, well-founded measure for
interaction effects between arbitrary feature subsets. The study of interaction
effects represents an inevitable step towards a comprehensive understanding of
black-box models and is particularly important for science applications. As
opposed to Shapley values, our novel measure maintains the original linear
scaling and is thus generally applicable to real-world problems.Comment: 28 pages, 13 Figures, major revision (completeness relation, new
experiments, comparison to Shapley values), code available at
https://github.com/PredDiff/PredDiff202
Reconstructing Kernel-based Machine Learning Force Fields with Super-linear Convergence
Kernel machines have sustained continuous progress in the field of quantum
chemistry. In particular, they have proven to be successful in the low-data
regime of force field reconstruction. This is because many physical invariances
and symmetries can be incorporated into the kernel function to compensate for
much larger datasets. So far, the scalability of this approach has however been
hindered by its cubical runtime in the number of training points. While it is
known, that iterative Krylov subspace solvers can overcome these burdens, they
crucially rely on effective preconditioners, which are elusive in practice.
Practical preconditioners need to be computationally efficient and numerically
robust at the same time. Here, we consider the broad class of Nystr\"om-type
methods to construct preconditioners based on successively more sophisticated
low-rank approximations of the original kernel matrix, each of which provides a
different set of computational trade-offs. All considered methods estimate the
relevant subspace spanned by the kernel matrix columns using different
strategies to identify a representative set of inducing points. Our
comprehensive study covers the full spectrum of approaches, starting from naive
random sampling to leverage score estimates and incomplete Cholesky
factorizations, up to exact SVD decompositions.Comment: 18 pages, 12 figures, preprin
Elm disease in the city of Malmö : a retrospective
Under större delen av 1900-talet utgjorde almen ett betydande inslag i Malmös grönska. FrÄn det att den aggressiva formen av almsjuka, orsakad av sporsÀcksvampen Ophistoma novo-ulmi, drabbade staden har 40 000 trÀd gÄtt förlorade. Den hÀr uppsatsens syfte Àr att skapa ett helhetsperspektiv över hur almsjukan i Malmö spreds och hanterades. Den bestÄr dels av en litteratur- och dokumentstudie och dels av en intervjustudie. I den sistnÀmnda har personer med professionell erfarenhet av almsjukan intervjuats.
Almsjukan Àr en vÀxtsjukdom som sprids frÄn alm till alm med hjÀlp av vektorer (i almsjukans fall almsplintborrar ur slÀktet Scolytus) eller via rotkontakt mellan smittade och friska trÀd. O. novo-ulmi fÄr sitt vÀrdtrÀd att vissna och senare dö. För att hantera almsjukan tillÀmpas framförallt regelbundna avverkningar av döda almar och trÀd dÀr almsplintborrarna lagt Àgg (s.k. botrÀd).
Almsjukan i Malmö upptÀcktes tidigt men kunde ÀndÄ inte begrÀnsas effektivt lÀngre Àn cirka 10 Är, ett mönster som med fÄ undantag upprepat sig överallt dÀr almsjukan dragit fram. I min uppsats har jag sammanfattat nÄgra organisatoriska och ekologiska förklaringar bakom almsjukans förödande utfall. Exempelvis frÄnvaro av avsatta medel och synkroniserat arbete frÄn olika myndigheter samt bristen pÄ mÄngfald i trÀdbestÄnden.Elms have been an important part of green spaces in the city of Malmö during the greater part of the 20th century. Since the introduction of Dutch elm disease (caused by the ascomycete fungi Ophistoma novo ulmi) to Malmö, the city has lost over 40 000 elms. The aim of this thesis is to analyse how Dutch elm disease spread and effected Malmö and how it was handled. The thesis contains a literature and document study in combination with an interview study in which the respondents all have professional experience of Dutch elm disease.
Dutch elm disease is a wilt disease that spreads from tree to tree either by vectors (in this case bark beetles in the genus Scolytus) or through root grafts. O. novo-ulmi causes wilt and later death of the host tree. Dutch elm disease can be managed by removal of infected trees and trees that are dead or dying and hence are possible breeding sites for elm bark beetles.
All though Dutch elm disease in Malmö was identified at an early stage the management project was not able to control it for a longer period than 10 years, a pattern which has been repeating itself at all sites where the disease has been a problem. My thesis has summarized a couple of ecological and organisational factors behind the effects of Dutch elm disease. Two examples are a lack of allocated money for disease management and a low diversity in the tree stands
Messung von physischer RĂŒstigkeit und geistiger KapazitĂ€t bei Senioren
"Zur KlĂ€rung der Hilfs- und BetreuungsbedĂŒrftigkeit alter Menschen veranlaĂte der Schweiz. Nationalfonds eine Untersuchung ĂŒber 'Arten und Grade der UnabhĂ€ngigkeit bei den Senioren'. Die gĂ€ngigen Theorien zum Problem schlieĂen einander aus. Anhand der Daten aus den Interviews mit 4'455 at Random ausgewĂ€hlter 60+jĂ€hriger Zielpersonen ergab sich, daĂ AktivitĂ€ten weniger Ursachen sondern eher Folgen eines gĂŒnstigen Verlaufes des Alterns sind. Der Handlungsspielraum der Senioren ergibt sich aus deren körperlichen und geistigen KapazitĂ€ten. Das sind die zentralen Befunde dieser Untersuchung. In den Interviews wurden diese durch hierzu speziell entwickelte Fragenbatterien bemessen. Im Test zur körperlichen RĂŒstigkeit wurden neben den Eigenerfahrungen des Instituts auch diejenigen anderer AnsĂ€tze (so I. Garrard und A. Bennet, E. Shanas, P. Towsends et al. DreilĂ€nderstudie, M. Lawtons et al.: Indices of Health, ferner P. Kempe und C. Closs' Erfahrungen mit Guttman-Skalen) genutzt. Der Test erfaĂt und differenziert zentrale BewegungslĂ€ufe, etwa die Dimensionen 'Gehen', 'Steigen', 'Heben', 'Sich beugen', 'Arme bewegen', 'Hand- und Fingergelenkigkeit', 'BewegungsablĂ€ufe'. Zur Skalierung diente das ordinale Verfahren der Guttman-Skala, in dem Höherleistungen aus- und Minderleistungen eingeschlossen werden. Das Verfahren ermöglicht die Einordnung in eine Gesamtskala von Leistungsstufen. Der Test zur Beurteilung der geistigen KapazitĂ€t wurde in Kontakten mit geriatrisch und psychiatrisch erfahrenen Experten erarbeitet. Erstrebt wurde die Fixierung geistiger FĂ€higkeiten, die eine Bedeutung fĂŒr die Beurteilung der SelbstĂ€ndigkeit haben. In Vortests mit Bewohnern von Altersheimen und Patienten psychiatrischer Kliniken wurden sie gefunden und erprobt. Dieses Testverfahren besteht aus einer verteilten Batterie von 17 Fragen. ErfaĂt wurden 'Grundfunktionen' als Voraussetzung zur LebensbewĂ€ltigung, Fragen zu 'Konzentration und FrischgedĂ€chtnis', Aufgaben zum 'Logischen Denkvermögen' und 'KurzzeitgedĂ€chtnis'. An die Stelle einer hierzu nicht leistbaren Skalierung tritt eine ZĂ€hlung und Bewertung." (Autorenreferat
Bundesfördermittel helfen FlutfolgeschĂ€den zu beseitigen: Landesstelle fĂŒr Bestandserhaltung koordiniert Projekt im Kloster Marienthal
Seit mehreren Jahren steht die Landesstelle fĂŒr Bestandserhaltung der Bibliothek des Klosters Marienthal in Ostritz beratend zur Seite. Folgerichtig ergaben sich wĂ€hrend und nach dem Hochwasser der NeiĂe im August 2010 besonders intensive fachliche Kontakte (siehe auch Thomas BĂŒrger; Michael Vogel: Kulturgutschutz und NotfallverbĂŒnde. â In: BIS. â 3(2010)4, S. 223 â 224). Zwar war die im ersten Stock gelegene barocke Saalbibliothek nicht unmittelbar von den Fluten betroffen, jedoch waren verschiedene im Erdgeschoss aufbewahrte Objekte durchnĂ€sst worden und die sehr ungĂŒnstigen raumklimatischen Bedingungen nach der Flut fĂŒhrten auch zu GefĂ€hrdungen vor allem durch Schimmel in höher gelegenen RĂ€umen
A execução fiscal e o novo CĂłdigo de Processo Civil: uma anĂĄlise crĂtica acerca do processo executivo fiscal frente a nova ordem processual brasileira
Diante do atual cenĂĄrio do sistema de cobrança fiscal no Brasil, foram analisados diversos Ăąngulos da estrutura implementada pela Lei 6.830 de 1980 e sua realidade prĂĄtica nos Tribunais do paĂs. Inicialmente, por meio de uma breve passagem histĂłrica, buscou-se demonstrar as origens do atual modelo, para entĂŁo analisar sua sistemĂĄtica e seus mecanismos prĂłprios. Como bem assentado, trata-se de modelo de cobrança estritamente judicial, onde a figura do juiz representa o prĂłprio cobrador fiscal, atuante em nome da fazenda pĂșblica. Contudo, o estudo apresentou de forma clara e contundente os decepcionantes dados de produtividade e eficiĂȘncia dos executivos fiscais no paĂs, o que contribui para a crise econĂŽmica do Estado brasileiro latu sensu e torna o processo de execução fiscal a classe processual mais congestionada do ordenamento pĂĄtrio, de acordo com os nĂșmeros levantados pelo Conselho Nacional de Justiça. Dessa forma, o trabalho buscou apontar diretrizes para a crise de produtividade observada, enxergando na influĂȘncia do Novo CĂłdigo de Processo Civil, instituĂdo pela Lei 13.105 de 2015, um caminho palatĂĄvel a ser trilhado. Desse modo, visou desconstruir conceitos ultrapassados para se alcançar o novo modelo processual, alinhado aos valores constitucionais, que deverĂĄ necessariamente pautar a sistemĂĄtica dos executivos fiscais, atravĂ©s do esforço das nossas Cortes. Assim, buscou-se demonstrar, sem utopia, que o processo de execução mais cooperativa e equilibrada serĂĄ tambĂ©m um processo mais eficiente, no que diz respeito Ă satisfação do crĂ©dito pĂșblico, conforme leciona boa parte da comunidade acadĂȘmica. Por outro lado, colacionou-se variados discursos que indicam a desjudicialização como fenĂŽmeno capaz de auxiliar na crise dos executivos fiscais. Em que pese algumas visĂ”es mais conservadoras, o trabalho demonstrou a viabilidade jurĂdica dos mecanismos ditos âdesjudicializadoresâ, a partir de construçÔes doutrinĂĄrias, visando em especial a localização do devedor e dos seus bens ainda no Ăąmbito administrativo. NĂŁo se limitou, contudo, Ă s controvĂ©rsias do meio acadĂȘmico, sendo tambĂ©m abordada jurisprudĂȘncia pertinente e projetos legislativos jĂĄ ventilados, dando maior atenção aos que despertaram mais atenção da comunidade jurĂdica. Foram finalmente analisados os principais pontos relevantes sobre o tema, para, enfim, restar a expectativa de que, a partir de uma reflexĂŁo de como nos enxergamos enquanto cidadĂŁos e de que tipo de relação se deve ter com Estado, possamos construir uma sistemĂĄtica de cobrança do crĂ©dito pĂșblico mais eficiente, pautada em valores democrĂĄticos e cooperativos
Corrosion Damage Analysis and Material Characterization of Sherman and Centaur - The Historic Military Tanks
A study of corrosion damage and material characterization of two historic military tanks, the Sherman and Centaur is reported. Experiments were conducted to analyse surface corrosion and corrosion propagation from surface to sub-surface. Significant surface corrosion was found, this phenomenon was further facilitated by delamination failure mechanisms. Corrosion depth for the Sherman was approximately 110 ”m, where sulphide inclusions were detected in the sub-surface analysis. The Centaurâs analysis showed corrosion pits at 100 ”m depth. These pits possess random geometrical configurations with evidence of sulfur, sodium and calcium
NemesĂthetĆ acĂ©lok Ă©s rozsdamentes acĂ©lok plazmanitridĂĄlĂĄsa
A BME GĂ©pĂ©szmĂ©rnöki Kar, AnyagtudomĂĄny Ă©s TechnolĂłgia TanszĂ©kĂ©n Ășj plazmanitridĂĄlĂł berendezĂ©s Ă©pĂŒlt. A kutatĂłmunka cĂ©lja, hogy elsĆkĂ©nt nemesĂthetĆ acĂ©lok, majd ausztenites Ă©s duplex korrĂłzióållĂł acĂ©lok kopĂĄsi tulajdonsĂĄgait vizsgĂĄljuk a plazmanitridĂĄlĂĄssal lĂ©trehozott felĂŒleteken. MetallogrĂĄfiai vizsgĂĄlattal, mikrokemĂ©nysĂ©g-mĂ©rĂ©ssel, pĂĄsztĂĄzĂł elektronmikroszkĂłppal Ă©s diffraktomĂ©teres vizsgĂĄlattal elemeztĂŒk a felĂŒleten kialakult rĂ©teg összetĂ©telĂ©t, vastagsĂĄgĂĄt, kemĂ©nysĂ©gĂ©t. A mintĂĄkat mind ipari, mind laboratĂłriumi körĂŒlmĂ©nyek között plazmanitridĂĄltuk. A rozsdamentes acĂ©lokat korrĂłziĂłs tesztnek vetettĂŒk alĂĄ, melyet az elĆzetes kutatĂĄsok alapjĂĄn Ă©rtĂ©keltĂŒnk. A vizsgĂĄlatok utĂĄn a kĂŒlönbözĆ technolĂłgiai vĂĄltozĂłkkal kĂ©szĂŒlt mintĂĄkat összehasonlĂtva megĂĄllapĂtottuk, hogy a kemĂ©nysĂ©gben eltĂ©rĂ©s nem mutatkozik, kizĂĄrĂłlag a rĂ©teg vastagsĂĄga eltĂ©rĆ
Characterization of a Be(p,xn) neutron source for fission yields measurements
We report on measurements performed at The Svedberg Laboratory (TSL) to
characterize a proton-neutron converter for independent fission yield studies
at the IGISOL-JYFLTRAP facility (Jyv\"askyl\"a, Finland). A 30 MeV proton beam
impinged on a 5 mm water-cooled Beryllium target. Two independent experimental
techniques have been used to measure the neutron spectrum: a Time of Flight
(TOF) system used to estimate the high-energy contribution, and a Bonner Sphere
Spectrometer able to provide precise results from thermal energies up to 20
MeV. An overlap between the energy regions covered by the two systems will
permit a cross-check of the results from the different techniques. In this
paper, the measurement and analysis techniques will be presented together with
some preliminary results.Comment: 3 pages, 3 figures, also submitted as proceedings of the
International Conference on Nuclear Data for Science and Technology 201
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