Opcije rabljenja čeličanske prašine u nemetalurškoj industriji

Recycling of by-products of the steelmaking process in electric arc (EAF) furnaces is an important activity from the perspective of environmental protection as well as the steelmaking industry itself. This article is a discussion concerning the selected research results in terms of utilisation of steelmaking dusts containing 4 - 12 % of zinc in manufacture of cement bricks, ceramic construction materials as well as colored glass products. The research conducted has implied that using steelmaking dusts in non-metallurgical industries is both possible and reasonable.Recikliranje nus proizvoda čeličanskih procesa u elektro lučnim pećima (ELP) je važna aktivnost sa gledišta zaštite okoliša kao i osobno za čeličansku industriju. Ovaj članak se tiče rasprave selektivnih rezultata istraživanja sa gledišta rabljene čeličanske prašine sa sadržajem 4-12 % cinka pri proizvodnji cementnih blokova, keramičkih materijala kao i obojenih staklenih proizvoda. Provedena istraživanja su ukazala da rabljenje čeličanske prašine u nemetalurškoj industriji je moguće i razborito

Copper production and trade in Poland during the COVID-19 epidemic

The SARS-CoV-2 virus outbreak has created turmoil in domestic economies around the world. The changes are visible in all industrial branches of the economy, including the market of metallic raw materials. The article reviews and analyzes the size of changes in the production and sales of copper and copper products in Poland in 2020, comparing the data in the previous years. The aim of the article is to assess the possible impact of the epidemic and related economic changes on the copper market in Poland

Determination of physico-chemical properties of fine-grained waste from the cleaning of iron casting

In the European Union one of the most important activities is the recovery and recycling of waste including foundry waste. In the article waste arising from production of iron casting was presented. Selected physic-chemical properties of iron-bearing waste were defined. Opportunities of waste management are related to their chemical construction as well as some physical properties. On the basic the results of research the solutions of foundry waste management were proposed

Twitter and the US stock market: the influence of micro‑bloggers on share prices

With the increased interest in social media over recent years, the role of information disseminated through avenues such as Twitter has become more widely perceived. This paper examines the mention of stocks on the US markets (NYSE and NASDAQ) by a number of financial micro-bloggers to establish whether their posts are reflected in price movements. The Twitter feeds are selected from syndicated and nonsyndicated authors. A substantial number of tweets were linked to the price movements of the mentioned assets and an event study methodology was used to ascertain whether these mentions carry any significant information or whether they are merely noise

Restricted-access al-mediated material transport in al contacting of pureGaB Ge-on-Si p+n diodes

The effectiveness of using nanometer-thin boron (PureB) layers as interdiffusion barrier to aluminum (Al) is studied for a contacting scheme specifically developed for fabricating germanium-on-silicon (Ge-on-Si) p + n photodiodes with an oxide-covered light entrance window. Contacting is achieved at the perimeter of the Ge-island anode directly to an Al interconnect metallization. The Ge is grown in oxide windows to the Si wafer and covered by a B and gallium (Ga) layer stack (PureGaB) composed of about a nanometer of Ga for forming the p + Ge region and 10 nm of B as an interdiffusion barrier to the Al. To form contact windows, the side-wall oxide is etched away, exposing a small tip of the Ge perimeter to Al that from this point travels about 5 μm into the bulk Ge crystal. In this process, Ge and Si materials are displaced, forming Ge-filled V-grooves at the Si surface. The Al coalesces in grains. This process is studied here by high-resolution cross-sectional transmission electron microscopy and energy dispersive x-ray spectroscopy that confirm the purities of the Ge and Al grains. Diodes are fabricated with different geometries and statistical current–voltage characterization reveals a spread that can be related to across-the-wafer variations in the contact processing. The I–V behavior is characterized by low dark current, low contact resistance, and breakdown voltages that are suitable for operation in avalanching modes. The restricted access to the Ge of the Al inducing the Ge and Si material transport does not destroy the very good electrical characteristics typical of PureGaB Ge-on-Si diodes

Broadband PureGaB Ge-on-Si photodiodes responsive in the ultraviolet to near-infrared range

Optical characterization of PureGaB germanium-on-silicon (Ge-on-Si) photodiodes was performed for wavelengths between 255 nm and 1550 nm. In PureGaB technology, chemical vapor deposition is used to grow germanium islands in oxide windows to the silicon substrate and then cap them in-situ with nm-thin layers of first gallium and then boron, thus forming nm-shallow p+n diodes. These PureGaB Ge-on-Si photodiodes are CMOS compatible and characterized by low leakage currents. Here they are shown to have high responsivity in the whole ultraviolet (UV) to near infrared (NIR) wavelength range. Particularly, two sets of diodes were studied with respect to possible detrimental effects of the Al metallization/alloying process steps on the responsivity. Al-mediated transport of the Ge and underlying Si was observed if the PureGaB layer, which forms a barrier to metal layers, did not cover all surfaces of the Ge islands. A simulation study was performed confirming that the presence of acceptor traps at the Ge/Si interface could decrease the otherwise high theoretically attainable responsivity of PureGaB Ge-on-Si photodiodes in the whole UV to NIR range. A modification of the device structure is proposed where the PureGaB layer covers not only the top surface of the Ge-islands, but also the sidewalls. It was found that to mitigate premature breakdown, it would be necessary to add p-doped guard rings in Si around the perimeter of Ge islands, but this PureGaB-all-around structure would not compromise the optical performance.</p