Search results for "Metallurgy"
showing 10 items of 1419 documents
Modeling and simulation of a High Pressure Roller Crusher for silicon carbide production
2011
Author's version of a chapter published in the book: 11th International Conference on Electrical Power Quality and Utilisation. Also available from the publisher at: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6128963&tag=1 This paper describes the modeling and simulation of High Pressure Roller Crusher (HPRC) for the production of silicon cabide grains. The study is to make a model for simulation of a High Pressure Roller Crusher. A High Pressure Roller Crusher (HPRC) is an important part in the production of silicon carbide, where the grains are crushed into powder form and then sieved into specified sizes based on its usage. This paper will present a model based on Johanson's…
Structure and Properties of YbZnSn, YbAgSn, and Yb2Pt2Pb
1999
Abstract YbZnSn, YbAgSn, and Yb2Pt2Pb were synthesized by reacting the elements in sealed tantalum tubes in a high-frequency furnace. The structures of YbAgSn and Yb2Pt2Pb were refined from single crystal X-ray data: YbAgPb type, P 6 m2, a=479.2(2) pm, c=1087.3(3) pm, wR2=0.050, BASF=0.34(8), 509 F2 values, 18 variables for YbAgSn and Er2Au2Sn type, a=776.0(1) pm, c=701.8(2) pm, wR2=0.072, 426 F2 values, 18 variables for Yb2Pt2Pb. The lattice constants of YbZnSn are confirmed: NdPtSb type, P63mc, a=464.7(1) pm, c=747.7(2) pm. The stannides YbZnSn and YbAgSn crystallize with superstructures of the AlB2 type. The zinc (silver) and tin atoms form ordered Zn3Sn3 and Ag3Sn3 hexagons, respectivel…
Investigation of diffusion and electromigration of hydrogen in palladium and PdAg alloy
1999
Abstract Diffusion and electromigration of hydrogen in PdH 0.1 , Pd 77 Ag 23 H 0.1 and Pd 50 Ag 50 H 0.1 alloy were measured by means of resistivity method. It is known that hydrogen migrates towards the cathode within the temperature range of 300–473 K in the PdH 0.1 and Pd 77 Ag 23 H 0.1 system. In Pd 50 Ag 50 H 0.1 , hydrogen migrates towards the cathode below 400 K, but towards the anode at higher temperatures. Its effective valency increases together with temperature. At the same time it satisfies the linear dependence on inverse specific resistance ρ : Z eff = Z i +( k / ρ ). The constants Z i and k have the following values: (1.05±0.01) and −(3.81±0.04)×10 −8 Ω m for hydrogen in PdH …
Surface versus bulk composition of a phosphate glass
1994
Transmission and conversion electron Mossbauer spectroscopy as well as photoelectron spectroscopy were applied to study alterations of the surface layer of an iron containing industrial phosphate glass as compared with its bulk. In the surface layer, after polishing and exposure to ambient atmosphere, Fe 2+ is partially oxidized to Fe 3+ . This oxidation, however, does not increase the O/P ratio in this layer, because it goes along with a strong leaching of network modifiers. This leaching leads to a net decrease of the O/P ratio because it overcompensates the relative oxygen increase by Fe 2+ oxidation and by uptake of water
Vanadium Carbide Dissolution during Austenitisation of a Model Microalloyed FeCV Steel
2005
High performance commercial micro alloyed steels contain elements such as vanadium, which leads to a fine dispersion of vanadium carbide precipitates. The precipitation state, in terms of volume fraction and size distribution, plays a significant role in final mechanical properties of the material. Different austenitisation heat treatments were performed on a model ternary alloy FeCV. Precipitation states were characterised combining different experimental techniques. TEM was used to identify the chemical composition of observed precipitates. ICP mass spectroscopy was performed to measure the volume fraction of precipitates. The size distribution was studied by SEM. Results are characterist…
Twitter sentiment as a weak signal in venture capital financing
2021
Abstract How do venture capitalists (VCs) incorporate weak and strong signals in the valuation of technology-based startups? Based on a sociocognitive perspective of signaling theory, we introduce Twitter sentiment as a novel and weak signal, which we juxtapose with patents as a traditional, strong signal. While we find a positive association between both signals and VCs' venture valuations, our results reveal that Twitter sentiment does not correlate with actual long-term investment success, whereas patents do. Additionally, we identify and test novelty and experience characteristics (i.e., startup age and VC firm experience) as boundary conditions for our proposed signal-valuation relatio…
Effects of Dissolved Complexation on REE Fate During Interactions between Volcanic Ash and Coexisting Fluids
2013
AbstractThis work analyzes REE behavior during the delivery of volcanic ash into a marine system and highlights the effects induced by dissolved carbonate and humate complexes on REE release. Kinetic experiments were carried out during a 6-month period using a batch method approach. Results show that the highest degree of REE leaching occurs during the early stage. Altered phases that crystallize induce REE sorption and dissolved complexation towards surface complexation, concurrent processes that are enhanced by Y/Ho, La/Yb, and Ce/Ce* changes, whereas dissolved humates and carbonates influence the dissolution rate of ash and the dissolved REE behavior.
First determination of magma-derived gas emissions from Bromo volcano, eastern Java (Indonesia)
2015
The composition and fluxes of volcanic gases released by persistent open-vent degassing at Bromo Volcano, east Java (Indonesia), were characterised in September 2014 from both in-situ Multi-GAS analysis and remote spectroscopic (dual UV camera) measurements of volcanic plume emissions. Our results demonstrate that Bromo volcanic gas is water-rich (H2O/SO2 ratios of 56-160) and has CO2/SO2 (4.1 +/- 0.7) and CO2/S-tot (3.2 +/- 0.7) ratios within the compositional range of other high-temperature magma-derived gases in Indonesia. H-2/H2O and H2S/SO2 ratios constrain a magmatic gas source with minimal temperature of 700 degrees C and oxygen fugacity of 10(-17)-10(-18) bars. UV camera sensing on …
Diffuse soil CO2 degassing from Linosa island
2014
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Continuous SO2 flux measurements for Vulcano Island, Italy
2012
<p>The La Fossa cone of Vulcano Island (Aeolian Archipelago, Italy) is a closed conduit volcano. Today, Vulcano Island is characterized by sulfataric activity, with a large fumarolic field that is mainly located in the summit area. A scanning differential optical absorption spectroscopy instrument designed by the Optical Sensing Group of Chalmers University of Technology in Göteborg, Sweden, was installed in the framework of the European project "Network for Observation of Volcanic and Atmospheric Change", in March 2008. This study presents the first dataset of SO<sub>2</sub> plume fluxes recorded for a closed volcanic system. Between 2008 and 2010, the SO<sub>2</…