102,402 research outputs found
Beneficiation of concentrated ultrafine suspensions with a Falcon UF concentrator
No full textFalcon concentrators are enhanced gravity separators designed for concentrating fine particles. The Falcon UF model is unique in that it is dedicated to beneficiation of ultrafines, one key feature being that it does not make use of any fluidization water. We investigated the physics of particle transport inside Falcon concentrators, and concluded that separation efficiency is governed by differential settling velocity. We derived and published a predictive model of the partition function under dilute conditions. We intend to extend the initial model to concentrated ultrafine suspensions for application to industrial scenarios by adding hindered settling to account for solid concentration effects
Fluid dynamics based modelling of the Falcon concentrator for ultrafine particle beneficiation
No full textEnhanced gravity separators are widely used in minerals beneficiation, as their superior gravity field enables them to separate particles within narrow classes of density and size. This study aims to shed light on the Falcon concentrator’s ability to separate particles within size and density ranges lower than usual, say 5 to 60 μm and 1.2 to 3.0 s.g. respectively. As differential particle settling is expected to be the prevailing separation mechanism under such conditions, this study presents the workings of a predictive Falcon separation model that embeds phenomenological fluid and particle flow simulation inside the Falcon’s flowing film. Adding to the novelty of modelling the Falcon concentrator
using a fluid mechanics approach, one point of practical significance within this work is the derivation of the Falcon’s partition function from fluid flow simulation results
Physical analysis and modeling of the Falcon concentrator for beneficiation of ultrafine particles
No full textA predictive model of the Falcon enhanced gravity separator has been derived from a physical analysis of its separation principle, and validated against experimental data. After summarizing the previous works that led to this model and the hypotheses on which they rely, the model is extended to cover a wide range of operating conditions and particle properties. The most significant development presented here is the extension of the analytical law to concentrated suspensions, which makes it applicable to actual plant operating conditions. Two examples of industrial use cases are described and studied by interrogation of the model: dredged sediment waste reduction and coal recovery from fine tailings. Comparisons with empirical studies available in the literature show a good agreement between model predictions and industrial data. The model is then used to identify separation efficiency limitations as well as possible solutions to overcome them. These two examples serve to show how this predictive model can be used to obtain valuable information to improve physical separation processes using a Falcon concentrator, or to evaluate Falcon separator’s abilities for new applications
Thomas Kjeller Johansen, Plato's Natural Philosophy: A Study of the Timaeus-Critias, Cambridge University Press, 2004, 218pp, $75.00 (hbk), ISBN 0521790670
No full textPeregrine Falcon Road to Recovery
No full textperegrine_roadrecoverypdf.pdf1970—Peregrine falcon is added to Endangered Species List
Recovery teams develop Regional recovery plans
Recovery actions implemented, including:
Protect/enhance habitat,
Minimize disturbance/mortality,
Monitor contaminants (DDT),
Reintroduce captive-bred birds
Recovery objectives achieved including number of breeding pairs
June 30, 1995—Notice of intent to propose
delisting of the peregrine falcon
Publish proposal to delist species, August 25, 1998
90-day public comment period
USFWS evaluates comments
USFWS issues final decision to
delist the peregrine falcon.
Once the peregrine is delisted, the Service will monitor its
status for a minimum of five years
If status declines significantly, the species can
be relisted
If status remains stable or
improves, ESA monitoring is
ended.
D s e l i t
Re a t i n
Peregrine is
at this stage
CLEARCHUS OF SOLI - (R.) Mayhew, (D.C.) Mirhady, (T.) Dorandi, (S.) White (edd., trans.) Clearchus of Soli. Text, Translation, and Discussion. Pp. x + 612. London and New York: Routledge, 2022. Cased, £120, US$160. ISBN: 978-0-367-70681-4.
No full textLetter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Some vocalisations of the Grey Falcon 'Falco hypoleucos'
No full textSound-recordings of some calls of the Grey Falcon 'Falco hypoleucos' (adult cackle calls, juvenile begging whines) are described and presented as sound spectrograms, and compared with some equivalent calls of the Peregrine Falcon 'F. peregrinus' (adult female cackle, juvenile begging whine, probable juvenile cackle). The Grey Falcon cackle calls are similar to those of the Peregrine, though variously softer and clearer, more 'squeaky' and/or more guttural (the Peregrine cackles being more strident and whining). Grey Falcon juvenile begging calls are more falsetto than those of the Peregrine. Fundamental frequencies differ slightly (Grey Falcon adult female cackle calls at ~700 Hz, Peregrine at ~1 kHz for juvenile begging calls, ~2 kHz for adult female cackle calls). The vocal data are consistent with the phylogenetic position of the Grey Falcon as basal to the Peregrine and 'great falcon' groups
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