Search results for "021102 mining & metallurgy"
showing 3 items of 13 documents
Evaluating pulp stiffness from fibre bundles by ultrasound
2012
A non-destructive ultrasonic tester was developed to measure the stiffness of pulp bundles. The mechanical properties of pulp are important when estimating the behaviour of paper under stress. Currently available pulp tests are tedious and alter the fibres structurally and mechanically. The developed tester employs (933 ± 15) kHz tweezer-like ultrasonic transducers and time-of-flight measurement through (9.0 ± 2.5) mm long and (0.8 ± 0.1) mm thick fibre bundles kept at (19.1 ± 0.4) °C and (62 ± 1)% RH. We determined the stiffness of soft wood pulps produced by three kraft pulping modifications: standard kraft pulp, (5.2 ± 0.4) GPa, prehydrolysis kraft pulp, (4.3 ± 0.4) GPa, and alkali extra…
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…
Geochemical fingerprints of brannerite (UTi 2 O 6 ): an integrated study
2020
AbstractBrannerite (UTi2O6) is among the major uranium-bearing minerals found in ore deposits, however as it has been long considered as a refractory mineral for leaching it is currently disregarded in ore deposits. Brannerite is found in a variety of geological environments with the most common occurrences being hydrothermal and pegmatitic. On the basis of scanning electron microscopy observations coupled with electron probe micro-analyses and laser ablation inductively-coupled plasma mass spectrometer analyses, this study describes the morphological features and the major- and trace-element abundances of brannerite samples from five hydrothermal and five pegmatitic localities across the w…