27 research outputs found
A Special Issue (Part-II): mafic-ultramafic rocks andalkaline-carbonatitic magmatism and associated hydrothermalmineralization – dedication to Lia N. Kogarko
Thisisthesecondpartofatwo-volumespecialis- sue of Open Geoscience (formerly Central European Jour- nal of Geosciences) that aims to be instrumental in pro- viding an update of Mac-Ultramac Rocks and Alkaline
Me3Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines
A simple and efficient protocol for the construction of 1-aminoisoquinolines was achieved by treating 2-(2-oxo-2- phenylethyl)benzonitriles with amines in the presence of Me 3 Al. The reaction proceeds via a domino nucleophilic addition with subsequent intramolecular cyclisation. This method provides a wide variety of substituted 1-aminoisoquinolines with good func- tional group tolerance. Furthermore, the synthetic utility of this protocol was demonstrated in the successful synthesis of the anti- tumor agent CWJ-a-5 in gram scale
Processing of ultrafine-size particulate metal matrix composites by advanced shear technology
Copyright @ 2009 ASM International. This paper was published in Metallurgical & Materials Transactions A 40A(3) and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Lack of efficient mixing technology to achieve a uniform distribution of fine-size reinforcement within the matrix and the high cost of producing components have hindered the widespread adaptation of particulate metal matrix composites (PMMCs) for engineering applications. A new rheo-processing method, the melt-conditioning high-pressure die-cast (MC-HPDC) process, has been developed for manufacturing near-net-shape components of high integrity. The MC-HPDC process adapts the well-established high shear dispersive mixing action of a twin-screw mechanism to the task of overcoming the cohesive force of the agglomerates under a high shear rate and high intensity of turbulence. This is followed by direct shaping of the slurry into near-net-shape components using an existing cold-chamber die-casting process. The results indicate that the MC-HPDC samples have a uniform distribution of ultrafine-sized SiC particles throughout the entire sample in the as-cast condition. Compared to those produced by conventional high-pressure die casting (HPDC), MC-HPDC samples have a much improved tensile strength and ductility.EP-SR
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Strength reduction of sewing threads during high speed sewing in an industrial lockstitch machine
Strength reduction in sewing threads during high speed sewing in industrial lockstitch machine
Alkali feldspar syenites with shoshonitic affinities from Chhotaudepur area: Implication for mantle metasomatism in the Deccan large igneous province
Two petrologically distinct alkali feldspar syenite bodies (AFS-1 and AFS-2) from Chhotaudepur area, Deccan Large Igneous Province are reported in the present work. AFS-1 is characterized by hypidiomorphic texture and consists of feldspar (Or55Ab43 to Or25Ab71), ferro-pargasite/ferro-pargasite hornblende, hastingsite, pyroxene (Wo47, En5, Fs46), magnetite and biotite. AFS-2 exhibits panidiomorphic texture with euhedral pyroxene (Wo47-50, En22-39, Fs12–31) set in a groundmass matrix of alkali feldspar (Or99Ab0.77 to Or1.33Ab98), titanite and magnetite. In comparison to AFS-1, higher elemental concentrations of Ba, Sr and ∑REE are observed in AFS-2. The average peralkaline index of the alkali feldspar syenites is ∼1 indicating their alkaline nature. Variation discrimination diagrams involving major and trace elements and their ratios demonstrate that these alkali feldspar syenites have a shoshonite affinity but emplaced in a within-plate and rifting environment. No evidence of crustal contamination is perceptible in the multi-element primitive mantle normalized diagram as well as in terms of trace elemental ratios. The enrichment of incompatible elements in the alkali feldspar syenites suggests the involvement of mantle metasomatism in their genesis
Petrogenesis of ultramafic rocks with abyssal peridotite affinity from the Central Bundelkhand Craton, India
The Bundelkhand craton in India preserves important records of archean geological evolution, where several ultramafic rocks belonging to the Babina Greenstone Belt (BGB) occur as isolated and oval shaped bodies. These rocks are composed of olivine, orthopyroxene, amphiboles, and serpentine along with accessory mineral phases like chromian spinel and ilmenite. Here we present the major and trace element geochemistry of these ultramafic rocks that are characterised by low SiO2 (45.16–49.00 wt%), high MgO (24.41–29.15 wt%) and moderate Fe2O3 (5.82–9.95 wt%) with high Ni (1164–1674 ppm), Cr (1532–3477 ppm) and Cu (14.7–39.5 ppm) suggesting primary magmatic nature. The rocks show low rare earth element (REE) content (ΣREE 2.1–3.5 ppm) with depleted LREE pattern and flat to slightly fractionated HREE pattern similar to abyssal peridotite signature. The Nb/Yb ratio ranges between 0.01 to 0.20 (average = 0.03), similar to that of N-MORB, suggesting magma derivation from a depleted mantle source, further substantiated by the Th/Yb vs. Ta/Yb plot. Trace elements like Ta and Pb show positive spikes, whereas La, Nb, Pr and Ce show depleted nature. The rocks generally have low platinum group elements (PGE) content (<150 ppb) except one sample where it goes up to 388 ppb. The ΣPPGE concentration is higher than ΣIPGE for all the samples and the high Pd/Ir ratio (7.55–20.98) indicating the derivation of these ultramafic rocks from low degree of partial melting. Our data suggest that the ultramafic rocks were derived from a depleted mantle source at a shallow depth with affinity towards abyssal peridotite. These rocks might represent residue after extraction of low degree melt (∼2–10%) in a mid-oceanic ridge (MOR) setting, which were captured and brought to shallow levels and subsequently exposed on the surface