1,588 research outputs found
Trace element and Nd–Sr isotopic composition of ultramafic lamprophyres from the East Antarctic Beaver Lake area
No full textThe trace element and Nd-Sr isotopic compositions of Cretaceous (110-117 Ma) ultramafic lamprophyres from the Beaver Lake area in East Antarctica, which are developed as sill, dyke and plug intrusions. have been investigated. Rare earth elements of lamprophyres are strongly fractionated, with LREE > 100 times chondrite, whereas HREE are < 10 times chondrite, presumably indicating the presence of residual garnet in the source region. A characteristic feature of the Beaver Lake rocks is low concentrations of Zr and Hf (Zr, 50-150 ppm: Hf, 1.0-5.0 ppm) and to a lesser extent Nb (17-90 ppm) which cause strong negative anomalies in the normalized trace element patterns. Eruption age-corrected Nd isotope values vary within narrow ranges (epsilon Nd-(t) = + 2.1 to + 4.3), whereas Sr isotope values show more variation (Sr-87/Sr-86((t)) = 0.704336-0.706431), similar to the isotopic compositions of other ultramafic lamprophyres. The genesis of the ultramafic lamprophyres is explained as a result of the gradual widening of the Lambert-Amery rift during the Phanerozoic. An increase in the geothermal gradient from cold continental conditions beneath the Archean block to the west may have resulted in grazing of the peridotite solidus at depths greater than 110 km. The initial carbonate-rich melts migrated upwards and froze as carbonate-bearing veins in the overlying lithosphere. Later upward and outward migration of the asthenosphere beneath the rift caused remelting of the veined region, resulting in melts of ultramafic lamprophyre composition with a mixed geochemical abundance and isotope signature from carbonate-rich veins and depleted peridotite wall-rock. The CO2-rich component of the lamprophyres is derived principally from the vein assemblage, from which phlogopite gives rise to the variable Sr isotopes, and baddeleyite to the differing Zr and Hf abundances. The difference between the lamprophyre facies of the Beaver Lake intrusions can be explained by minor amounts of olivine and Cr-spinel fractionation. (C) 2001 Elsevier Science B.V, All rights reserved
Fractionation of Nb and Ta from Zr and Hf at mantle depths: the role of titanian pargasite and kaersutite
No full textSelective enrichment or depletion in either Zr and Hf (HFSE(4+)) or Nb and Ta (HFSE(5+)) is a feature commonly observed in many mantle-derived melts and amphiboles occurring as either disseminated minerals in mantle xenoliths and peridotite massifs or in vein assemblages cutting these rocks. The fractionation of Nb from Zr seen in natural mantle amphiboles suggests that their incorporation is governed by different crystal-chemical mechanisms. An extensive set of new partitioning experiments between pargasite-kaersutite and melt under upper-mantle conditions shows that HFSE incorporation and fractionation depends on amphibole major-element composition and the presence or absence of dehydrogenation. Multiple regression analysis shows that (Amph/I)D(Nb/Zr) is strongly dependent on the mg-number of the amphibole as a result of a combination of amphibole and melt structure effects, so that the following generalizations apply: (1) high-mg-number amphiboles crystallized from unmodified mantle melts more easily incorporate Zr relative to Nb leading to an increase of the Nb/Zr ratio in the residual melt; (2) low-mg-number amphiboles, such as those found in veins cutting peridotites, may strongly deplete the residual melt in Nb and cause very low Nb/Zr in residual melts. Implications and applications to mantle environments are discussed
Sketches for the biography of S.F. Rusova (1856–1940)
No full textМета статті – проаналізувати відомі факти біографії С.Ф. Русової, аби визначити, як вона,
попутниця діячів українського ліберально-демократичного та російського народницького рухів, визначилася й скерувала свою надзвичайну енергію на українську справу. Методи: історико-систематичний та аналітичний. Наукова новизна: уперше звернено увагу не на просвітницьку та педагогічну діяльність, про яку написано багато статей і книг, а власне на біографію С.Ф. Русової, яка
складається з двох частин: української та емігрантської. Висновки: український період її життя
визначається роздвоєнням політичної думки – між українством і російським визвольним рухом. В
еміграції 65-річна С.Ф. Русова, потрапивши в українське середовище, яке впливало на перебіг та
кристалізацію національного руху, віддано служила українству. За основу статті взято книжку
С.Ф. Русової «Мої спомини» (1937), видану у Львові кооперативним видавництвом «Хортиця», заснованим групою емігрантів із Наддніпрянщини наприкінці 1928 р. У передмові чітко визначена позиція видавництва як до авторки спогадів, так і до їх змісту. Вона близька авторці цієї статті.
Видавці зазначають, що в мемуарах зображені різні постаті: ті, які брали активну участь в українському визвольному процесі, і ті, котрі лише «творили близьке балянсування між українством і
загально-московським визвольним рухом» та відзначалися роздвоєнням політичної думки. С.Ф. Русова, на наш погляд, належала до других. Лише в еміграції в Празі вона стала свідомою українкою.
Цей заключний етап життя Софії Федорівни – тема для іншої студії. Автором же окреслений
життєпис С.Ф. Русової в Україні від дитинства до 1921 р., коли вона змушена була залишити
Батьківщину. Ця стаття – лише скромні начерки, в яких відображено діяльність ліберальної української інтелігенції 1870-х рр. – поч. ХХ ст. у контексті того, що в їхньому середовищі відбувався
процес духовного формування С.Ф. Русової, створювався ідейний багаж і моральні норми та образ
життя розумної, освіченої, суперечливої, гонорової жінки, яка постійно перебувала в процесі доволі напружених, болісних шукань.The purpose of the article – is to analyze the known facts of the biography of S.F. Rusova, in order to
determine how she, a fellow traveler of the Ukrainian liberal-democratic and Russian populist movements,
finally made up her mind and directed her extraordinary energy to the Ukrainian cause. Methods: historical-
systematic and analytical. Scientific novelty: for the first time, attention is drawn not to educational
and pedagogical activities, about which many articles and books have been published, but to the biography
of S.F. Rusova, which consists of two parts: Ukrainian and emigrant. Conclusions: the Ukrainian period of
her life is characterized by a bifurcation of political opinion – between Ukrainianism and the Russian liberation
movement. During her emigration, 65-year-old S.F. Rusova, by the will of fate, found herself in the
Ukrainian environment, which influenced the course and crystallization of the national movement, devotedly
served the Ukrainian nation. The basis of the article is the book «My memories» (1937) by S.F. Rusova,
published in Lviv by the cooperative publishing house «Khortytsia», founded by a group of emigrants from
the Naddniprianshchyna at the end of 1928. The preface clearly defines the position of the publishing house
both towards the author of the memoirs and their content. This position is close to the author of this
article. The publishers note that the memoirs depict different people: those who took an active part in the
Ukrainian liberation process and those who only «created a close balance between Ukrainianness and the
all-Moscow liberation movement» and were marked by a split in political opinion. S.F. Rusova, in our opinion,
belonged to the second ones. She became a conscious Ukrainian only when she emigrated to Prague.
This final stage of Sofia Fedorivnaʼs life is a topic for another studio. The author also outlines the biography
of S.F. Rusova in Ukraine from her childhood until 1921, when she was forced to leave the Motherland.
This article is only a modest sketch, which reflects the activities of the liberal Ukrainian intelligentsia
of the 1870s – the beginning of the 20th c. in the context of the fact that in their environment the process of
spiritual formation of S.F. Rusova took place, ideological baggage and moral norms and a way of life were
created an intelligent, educated, controversial, honorable woman who was constantly in the process of
quite intense, painful searches
Trace element abundances in rutiles from eclogites and associated garnet mica schists
No full textWe present electron microprobe and laser ablation microprobe (LAM) data for a range of high field strength (Zr, Nb, Me, Sri, Sb, Hf, Ta, W) and other trace elements (Al, Si, Ca, V, Cr, Mn, Fe, Pb, Th, U) in rutile from eclogites and garnet mica schists, from Trescolmen. Central Alps. Most analysed rutiles are homogeneous (at least for Nb, Cr, W, Zr, V and Fe), both on a single grain scale and between grains from a single thin section. Concentrations of V, Zr, Nb, Sb and W determined by both electron and laser ablation microprobe techniques yield similar results and confirm the reliability of the analytical methods within estimated precision. Measurements of trace element contents of coexisting phases in eclogites and their modal abundances show that rutile is the dominant carrier ( > 90% of whole rock content) for Ti, Nb, Sb, Ta and W as well as an important carrier (5-45% of the whole rock content) for V, Cr, Me and Sri. The crystallographic implications are that, for relatively rigid crystal sites such as in rutile, trace elements with a similar ionic radius are preferred over trace elements with the same charge but deviating size. Our results demonstrate the utility of rutile chemistry in the following applications: (1) By using a combination of the measured TiO2 content of the whole rock and the trace element concentration of rutile, precise whole rock data on elements that are either difficult to analyze by conventional techniques such as XRF or solution ICP-MS (Nb, Sb, Ta, W) or may be susceptible to late stage alteration (Sb) can be estimated. (2) Trace element contents of detrital rutile grains are a potentially powerful toot for sedimentary provenance studies since they reflect key element ratios (e.g,, Nb/TiO2 and Cr/TiO2) of their source rocks. In addition, measurements of trace elements in detrital rutiles might help distinguish possible source rocks, e.g., high-grade metamorphic rocks such as eclogites and high-pressure granulites from hydrothermal ore deposits and kimberlites. In view of the dominance of rutile in the Sb budget of subducting oceanic crust, and the enrichment of Sb in the slab component of subduction zones. additional experimental studies on Sb-partitioning between rutile and fluid are needed in order to understand the behaviour of Sb in subduction zones. (C) 2002 Elsevier Science B.V All rights reserved
Scientific Research Methodology for Library & Information Science Research: With Information System Development Methodology as Example
No full text近年來圖書館學與資訊科學有學科領域融合的現象。因為學科領域融合的結果，學科內涵的包容範圍擴大；過去傳統的圖書館學之研究，比較多關於社會科學層面之研究，因此，社會科學的研究方法，已在圖書館學的研究中，成為成熟化的一套研究方法。但是，自從圖書館自動化與資料庫系統建置也成為圖書館學中重要的一環之後，圖書館學的科學層面之研究益形重要，然而相對的研究方法，在圖書館學的研究中，並不及社會科學的研究方法一般成熟。為了幫助圖書館學中的技術科學領域，尋找更能有效解決問題的方法，以提升作業績效與服務上的讀者滿意度，本文乃研究有關科學研究方法的理論，參酌資訊科學領域的學者對於研究方法的見解，以系統開發的研究為例，彙整可行的一套研究方法，而論述科學技術性的作業與系統開發等相關研究，可以採用科學研究的方法。本文除了討論圖書資訊學科學研究法的基本精神與可能的步驟之外，並分析科學研究法的實質效益，希望能為圖書資訊學中的技術科學研究，指出可行的研究途徑，冀期圖書館學的科學研究方法終能發展至成熟之水準，而裨益日益重要的圖書館學之相關科學研究。The cross boundary research between library science and information science shows a great advancement in recent years. In the past, discourse of most researchers in library science had their focus on social aspects; therefore, the adopted sociology research methodologies have developed to a sophisticated level. In fact, the cross-disciplinary development has brought changes to library science research paradigm. With the broader scope of current library and information sciences, it would be very useful if we could also develop suitable research methodology for scientific researches. It is believed that
suitable research methodology could help solve problems in an effective way so as to ensure good operational performance and user satisfaction. Reviewing some theories
of scientific researches and scholars opinions regarding information science research methodologies, the author had information system development research as an example
and advocated that researches concerning technical services of library science needed to adopt scientific research methodologies. The author also introduced the positive heuristic
research approach and associated aspects that need to be included in the process for scientific researches of information system development and pointed out the possible
benefits of a scientific research approach for such researches. It is hoped that this initial discussion could anticipate the development of a set of sophisticated scientific research
methodology for library science researchers and be beneficial
Interferometric coherent Fourier scatterometry: a method for obtaining high sensitivity in the optical inverse-grating problem
No full textGreen 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. 075707-1 t/m 075707-9ImPhys/Optic
Phytofiltration of arsenic and cadmium from the water environment using Micranthemum umbrosum(J.F. Gmel) S.F. Blake as a hyperaccumulator
No full textArsenic (As) and cadmium (Cd) pollution in water is an important global issue. Phytofiltration is an eco-friendly technology that helps clean up pollutants using ornamental plants, such as Micranthemum umbrosum (J.F. Gmel) S.F. Blake. After a seven-day hydroponic experiment, M. umbrosum removed 79.3–89.5% As and 60–73.1% Cd from 0 to 1.0 μg As mL–1 and 0.3 to 30.0 μg Cd mL–1 solutions, respectively. For As treatment, root to stem and stem to leaf translocation factors greater than 1.0 indicated that accumulation of As in leaves was large compared to that in stem and roots. However, the accumulation of Cd in roots was higher than that in the leaves and stem. In addition, M. umbrosum completely removed Cd within three days from 0.38 to around 0 μg mL–1Cd in the solution when the plant was exchanged daily. Bio-concentration factors (2350 for As and 3027 for Cd) for M. umbrosum were higher than for other As and Cd phytoremediators. The results show that M. umbrosum can be an effective accumulator of Cd and a hyper-accumulator of As, as it can lower As toxicity to a level close to the limit recommended by the World Health Organization (0.01 μg As mL–1
Absorbing new subjects: holography as an analog of photography
No full textI discuss the early history of holography and explore how perceptions, applications, and forecasts of the subject were shaped by prior experience. I focus on the work of Dennis Gabor (1900–1979) in England,Yury N. Denisyuk (b. 1924) in the Soviet Union, and Emmett N. Leith (1927–2005) and Juris Upatnieks (b. 1936) in the United States. I show that the evolution of holography was simultaneously promoted and constrained by its identification as an analog of photography, an association that influenced its assessment by successive audiences of practitioners, entrepreneurs, and consumers. One consequence is that holography can be seen as an example of a modern technical subject that has been shaped by cultural influences more powerfully than generally appreciated.
Conversely, the understanding of this new science and technology in terms of an older one helps
to explain why the cultural effects of holography have been more muted than anticipated by forecasters
between the 1960s and 1990s
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