241 research outputs found
Ore dressing laboratory for the Missouri School of Mines and Metallurgy, Rolla, Missouri: design, description, drawings for erection, bills of material, and specifications
The work of preparing suitable drawings and specifications for the construction of the new Ore Dressing Laboratory of the Missouri School of Mines and Metallurgy was begun about August 15, 1909. At that time general plans, as shown in drawings No. 1 and No. 2, were drawn up and submitted for approvaleaf With certain minor alterations, to be mentioned under the section on specifications, these plans will be followed in the installation of machinery. Other detail drawings were made by the class in Ore Dressing Problems under the direction of the writer during the school term ending March 12, 1910. It is not intended that this work shall contain such complete plans, specifications, and detail working drawings as would be necessary if the installation were to be made by outside contractors. The work of installation and construction will be conducted during the summer of 1910 by mechanics in the employ of the school and under the supervision of the writer, or under the direction of some one else equally familiar with the conditions at hand. On this account the specifications and working drawings are not complete in all details, as a few verbal instructions at the time of installation, from one familiar with the work, are frequently more useful to the mechanic than a sheet of detail drawings and pages of specifications --Introduction, page 1
The thermal conductivity of refractories
The usefulness of correct data in regard to the thermal conductivity of refractories and other materials used in the construction of metallurgical and industrial furnaces is quite generally recognized. Numerous investigations of this property of refractories have been conducted, and in many cases the published data of different investigators are somewhat conflicting. This is particularly true of figures pertaining to materials intended for use at high temperatures, and it is with such materials that the metallurgist is mot interested. The difficulties in the way of precise determinations of thermal conductivities at elevated temperatures are numerous, and it is not particularly surprising that there exists a set of data for each method of determination, the figures of which fail to agree closely with those obtained by other methods. However, it should be remembered that the variations in the figures of different observers are doubtless due to variations in the materials tested as well as to differences between, or inaccuracies of, the methods employed. The present paper deals with the methods and results of an investigation designed to develop a practical and reasonably accurate means of determining the thermal conductivity of regular kinds of brick, under conditions approaching those of practice, and without the necessity of preparing special shapes or samples of the materials being tested. In reviewing the methods that have been used and proposed for determining the conductivity of refractory materials, they fall naturally into three general classes, calorimeter methods, measured heat-input methods, and comparison methods --Page 285
The effect of certain minerals upon the volatilization of silver chloride
The work undertaken in this investigation was first suggested in connection with the analytical determination of Silver and Chlorine by weighing silver chloride. Later, however, the experiments assumed a metallurgical character. The final purpose of the experiments was to determine the effect of a few of the common mineral constituents of ores on the loss of silver during a chloridizing roast. In the metallurgy of silver it is frequently necessary to change the silver bearing minerals into silver chloride --page 1
Arbitrary-order non-linear contribution to self-steepening
Based on the recently published generalized Miller formula, we derive the
spectral dependence of the contribution of arbitrary-order non-linear indices
to the group-velocity index. We show that in the context of laser filamentation
in gases all experimentally-accessible orders (up to the -order
non-linear susceptibility in air and in argon) have
contributions of alternative signs and similar magnitudes. Moreover, we show
both analytically and numerically that the dispersion term of the non-linear
indices must be considered when computing the intensity-dependent group
velocity.Comment: 10 pages, 3 figures (14 panels
An application of interpolating scaling functions to wave packet propagation
Wave packet propagation in the basis of interpolating scaling functions (ISF)
is studied. The ISF are well known in the multiresolution analysis based on
spline biorthogonal wavelets. The ISF form a cardinal basis set corresponding
to an equidistantly spaced grid. They have compact support of the size
determined by the underlying interpolating polynomial that is used to generate
ISF. In this basis the potential energy matrix is diagonal and the kinetic
energy matrix is sparse and, in the 1D case, has a band-diagonal structure. An
important feature of the basis is that matrix elements of a Hamiltonian are
exactly computed by means of simple algebraic transformations efficiently
implemented numerically. Therefore the number of grid points and the order of
the underlying interpolating polynomial can easily be varied allowing one to
approach the accuracy of pseudospectral methods in a regular manner, similar to
high order finite difference methods. The results of numerical simulations of
an H+H_2 collinear collision show that the ISF provide one with an accurate and
efficient representation for use in the wave packet propagation method.Comment: plain Latex, 11 pages, 4 figures attached in the JPEG forma
Patient participation in ERS guidelines and research projects:the EMBARC experience
The European Multicentre Bronchiectasis Audit and Research Collaboration (EMBARC) is a European Respiratory Society (ERS) Clinical Research Collaboration dedicated to improving research and clinical care for people with bronchiectasis. EMBARC has created a European Bronchiectasis Registry, funded by the ERS and by the European Union (EU) Innovative Medicines Initiative Programme. From the outset, EMBARC had the ambition to be a patient-focussed project. In contrast to many respiratory diseases, however, there are no specific patient charities or European patient organisations for patients with bronchiectasis and no existing infrastructure for patient engagement. This article describes the experience of EMBARC and the European Lung Foundation in establishing a patient advisory group and then engaging this group in European guidelines, an international registry and a series of research studies. Patient involvement in research, clinical guidelines and educational activities is increasingly advocated and increasingly important. Genuine patient engagement can achieve a number of goals that are critical to the success of an EU project, including focussing activities on patient priorities, allowing patients to direct the clinical and research agenda, and dissemination of guidelines and research findings to patients and the general public. Here, we review lessons learned and provide guidance for future ERS task forces, EU-funded projects or clinical research collaborations that are considering patient involvement.
Educational aims
To understand the different ways in which patients can contribute to clinical guidelines, research projects and educational activities. To understand the barriers and potential solutions to these barriers from a physician’s perspective, in order to ensure meaningful patient involvement in clinical projects. To understand the barriers and potential solutions from a patient’s perspective, in order to meaningfully involve patients in clinical projects
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Components of the female sex pheromone of the newly-described canola flower midge, Contarinia brassicola
The canola flower midge, Contarinia brassicola Sinclair (Diptera: Cecidomyiidae), is a newly-described species that induces galls on canola, Brassica napus Linnaeus and Brassica rapa Linnaeus (Brassicaceae). Identification of the sex pheromone of C. brassicola is essential to developing monitoring tools to elucidate the geographic range and hosts of this new pest, and the extent to which it threatens the $30 billion Canadian canola industry. The aim of this study was to identify and synthesize the female-produced sex pheromone of C. brassicola and demonstrate its effectiveness in attracting males to traps in the field. Two peaks were identified through GC-EAG analysis of female-produced volatiles which elicited electrophysiological responses in male antennae. These peaks were initially characterized through GC–MS and synthesis as 2,7-diacetoxynonane (major component) and 2-acetoxynonane (minor component), and the racemic compounds elicited EAG responses in male antennae. All four stereoisomers of 2,7-diacetoxynonane were synthesized and the naturally-produced compound was shown to be primarily the (2R,7S)-isomer by analysis on an enantioselective GC column, with a small amount of (2R,7R)-2,7-diacetoxynonane also present. The configuration of the minor component could not be determined because of the small amount present, but this was assumed to be (2R)-2-acetoxynonane by comparison with the configuration of the other two components. In field trials, none of the four stereoisomers of 2,7-diacetoxynonane, presented individually or as a racemic mixture, was attractive to male C. brassicola. However, dispensers loaded with a 10 µg:1 µg blend of (2R,7S)- and (2R,7R)-2,7-diacetoxynonane caught large numbers of male C. brassicola and significantly more than other blends tested. The addition of 0.5 µg of (2R)-2-acetoxynonane to this blend further increased the number of males caught. In future work, we will seek to identify the optimum trapping protocol for the application of the pheromone in monitoring and surveillance
A spectral method for the wave equation of divergence-free vectors and symmetric tensors inside a sphere
The wave equation for vectors and symmetric tensors in spherical coordinates
is studied under the divergence-free constraint. We describe a numerical
method, based on the spectral decomposition of vector/tensor components onto
spherical harmonics, that allows for the evolution of only those scalar fields
which correspond to the divergence-free degrees of freedom of the
vector/tensor. The full vector/tensor field is recovered at each time-step from
these two (in the vector case), or three (symmetric tensor case) scalar fields,
through the solution of a first-order system of ordinary differential equations
(ODE) for each spherical harmonic. The correspondence with the
poloidal-toroidal decomposition is shown for the vector case. Numerical tests
are presented using an explicit Chebyshev-tau method for the radial coordinate.Comment: 25 pages, 4 figures, to appear in Journal of Computational Physic
Dissipative Kerr solitons in optical microresonators
This chapter describes the discovery and stable generation of temporal
dissipative Kerr solitons in continuous-wave (CW) laser driven optical
microresonators. The experimental signatures as well as the temporal and
spectral characteristics of this class of bright solitons are discussed.
Moreover, analytical and numerical descriptions are presented that do not only
reproduce qualitative features but can also be used to accurately model and
predict the characteristics of experimental systems. Particular emphasis lies
on temporal dissipative Kerr solitons with regard to optical frequency comb
generation where they are of particular importance. Here, one example is
spectral broadening and self-referencing enabled by the ultra-short pulsed
nature of the solitons. Another example is dissipative Kerr soliton formation
in integrated on-chip microresonators where the emission of a dispersive wave
allows for the direct generation of unprecedentedly broadband and coherent
soliton spectra with smooth spectral envelope.Comment: To appear in "Nonlinear optical cavity dynamics", ed. Ph. Grel
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