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Polymetallic mineralisation at Hornkullen, Western Bergslagen: a metamorphosed Svecofennian formation?

Andersson S.

Geology, Geophysics and Environment

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2012

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Vol. 38, no. 4

454--455

EN

Although the Fe-Pb-Cu-(As-Ag) mineralization at Hornkullen in the classic Bergslagen ore province has been a subject of economical assessments earlier in addition of being mined intermittently during the last 100s of years, the metallogenesis of the deposit is poorly constrained. The region enclosing the deposit has experienced a rather complex geological and tectonic evolution; consequently several conceivable processes that could have influenced the mineralization need to be considered. The mineralization, which is situated in the western part of the Bergslagen province in Sweden, is hosted in ca 1.90-1.88 Ga Svecofennian metavolcanic and metasedimentary rocks. These were deposited in association with an extensional back-arc system inboard an active continental magmatic region (Allen et al. 1996). This succession subsequent underwent deformation and metamorphism during the Svecokarelian orogeny in regional greenschist to amphibolite facies (e.g. Stephens et al. 2008). At the western margin, the area was later intruded by younger granitoid rocks, (referred to as the GSDG intrusive rocks suite (Stephens et al. 2009) or the Trans-scandinavian Igneous Belt (e.g. Hogdahl et al. 2004), locally the so-called Filipstad granite, dated at 1783 ± 10 Ma (Jarl & Johansson, 1988). The metasupracrustal rocks in the Hornkullen area are enclosed as an inlier in this intrusive suite. The region has also locally been affected by the ca 1.0-0.9 Ga Sveconorwegian orogeny (e.g. Stephens et al. 2009), probably in a brittle regime. The present hypothesis is that the mineralization is syngenetic, i.e. formed in conjunction with the Svecofennian volcanic activity. However, as stressed so far, the mineralization has been affected by several thermal and deformational processes following its formation. The aim of this project is therefore to assess whether the deposit comprises of metamorphically overprinted, syn-volcanic assemblages or not. To assess this, comprehensive studies of phase and textural relations on ore minerals were conducted. Additionally, fluid inclusion analysis is planned that would give further constrain on the ore-forming fluid. Tentative results so far suggest overprinting of brittle structures to some extent in the ore mineralogy.

2

Detemination of a heat transfer between injected diesel fuel and a temperature controlled wall

Jedrzejowski S., Magnusson A., Andersson S.

Journal of KONES

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2006

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Vol. 13, No. 2

179-185

EN

The paper presents results of the experimental determination of heat fluxes between diesel fuel jet and a steel wall. The experiments were performed in the high pressure and temperature rig at the Chalmers University. The experimental stand allowed setting the pressures and the temperatures in the chamber similar to the conditions in a diesel engine during the compression stroke. A standard common rail injecting system and an injector with a single hole nozzle were used. The measurements were taken for different pressures/temperature combinations. However, in respect to have similar jet formation conditions and fuel droplets penetration range, the air density in the chamber was kept on constant level. The temperature-controlled wall was mounted perpendicular to the fuel jet. The wall was equipped with coaxial thermocouples for recording the surface temperatures. The thermocouples had very thin vacuum deposited junctions that offered very fast response. The recorded time histories of the surface temperatures were used to calculate the local heat fluxes on a basis of the one-dimensional transient heat conduction model. The experimental chamber had an optical access allowing observing the jet and the swirl formation when the fuel reached the wall. A high-speed camera was used to record the jet behaviour.

3

Radiowy mieszacz próbkujący z konwersją bezpośrednią i dużym tłumieniem w kanale pasożytniczym

Andersson S., Konopacki J., Dąbrowski J., Svensson C.

Elektronika : konstrukcje, technologie, zastosowania

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2005

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Vol. 46, nr 10

11-13

PL

Przedstawiono mieszacz z konwersją bezpośrednią wykorzystujący technikę próbkowania. W przyjętym rozwiązaniu sygnał radiowy jest próbkowany i poddawany filtracji oraz decymacji. Czynności te zrealizowano w technologii CMOS z przełączanymi kondensatorami. Filtracja zapewnia redukcję szumów i zabezpiecza przed nakładaniem się widma powstającym w wyniku decymacji. Do ilustracji użyto sygnału w paśmie 2,4 GHz i szerokości 20 MHz, zgodnego ze standardem Wi-Fi WLAN.

EN

In this paper we present a zero-IF down-conversation mixer using sampling technique. The sampled RF signal is subjected to filtering and decimation, all performed with SC circuits implemented in CMOS. The filtering is aimed at rejecting noise and interferers (images) arising during decimation. For demonstration purposes an RF signal of 20 MHz bandwidth in the 2.4 GHz band, consistent with Wi-Fi WLAN standard, was chosen.