549 research outputs found
Use of inorganic fertiliser in place of poultry manure for rehabilitation of gold and bauxite ore refining residues
Ore refining residues are difficult substrates for revegetation because they often contain extremely low plant available levels of one or more essential elements (Hossner and Hons 1992). Organic amendments would generally be attractive additions for revegetation because residues also contain little organic matter, and organic amendments may also ameliorate elevated concentrations of salts and other elements. However organic materials are generally not available on mine sites in sufficient quantities and they are bulky handle. In the present study, the opportunities for substituting inorganic fertilisers in place of poultry manure were investigated for revegetation of three alkaline, variably saline residues: bauxite residue (mixed sand and clay fractions), bauxite residue sand, and gold refining residue from mined oxide clays
Design and Evaluation of a Primary / Secondary Pumping System for a Heat Pump Assisted Solar Thermal Loop
A heat pump assisted solar thermal system was designed, commissioned, tested and analyzed over a period of two years. The unique system uses solar energy whenever it is available, but switches to heat pump mode at night or whenever there is a lack of solar energy. The solar thermal energy is added by a variety of flat plat solar collectors and an evacuated tube heat pipe solar collector. The working medium in the entire system is a 50% mixture of propylene glycol and water for freeze protection. During the design and evaluation the primary / secondary pumping system was the focus of the evaluation. Testing within this research focused on the operation modes, pump stability, and system efficiency. It was found that the system was in full operation, the pumps were stable and that the efficiency factor of the system was 1.95
Road development and Indigenous hunting in Tanah Papua: Connecting the facts for future wildlife conservation agendas
Road development is increasing worldwide. Generally, examples of road building in tropical countries demonstrate that road access can assist the fight against rural poverty, but such developments are also linked to deforestation, pollution, invasions of exotic species, and environmental degradation. For Papua and West Papua provinces (Tanah Papua) in Indonesia, the development of the provincial road network is intended to improve the rural economy, aiming to alleviate poverty within isolated rural areas. However, road development can pose particularly challenging problems to rural and Indigenous communities. Poorly planned roads can be devastating when they provide easy access to illegal hunting that threatens endangered species. In this study, we discuss how road development in Tanah Papua has changed indigenous hunting. Native Papuans have benefited from improved road access, which allows them to sell their agricultural products at local markets. Increased road connectivity has also changed how local people use natural resources and forest products, moving from subsistence to a more market-based orientation. Although policies on infrastructure development including roads form part of Indonesia’s national program, they are not automatically compatible with a sustainable development program in Tanah Papua. To foster more equitable and sustainable road development, government agencies must improve their overall coordination of further road expansion plans by promoting green infrastructure that supports the sustainable use of natural resources in a way that is reconciled with traditional knowledge of local people. Such efforts may also have positive effects on the efforts to protect biodiversity within the wider government conservation agendas
Superconductivity in epitaxial thin films of NaxCoO2 y D2O
The observation of superconductivity in the layered transition metal oxide
NaxCoO2 y H2O (K. Takada et al., Nature 422, 53 (2003)) has caused a tremendous
upsurge of scientific interest due to its similarities and its differences to
the copper based high-temperature superconductors. Two years after the
discovery, we report the fabrication of single-phase superconducting epitaxial
thin films of Na0.3CoO2 x 1.3 D2O grown by pulsed laser deposition technique.
This opens additional roads for experimental research exploring the
superconducting state and the phase diagram of this unconventional material.Comment: 3 pages, 5 figure
DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. V. Variables in the Field M31F
We undertook a long term project, DIRECT, to obtain the direct distances to
two important galaxies in the cosmological distance ladder -- M31 and M33 --
using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult
to detect, DEBs provide us with the potential to determine these distances with
an accuracy better than 5%. The extensive photometry obtained in order to
detect DEBs provides us with good light curves for the Cepheid variables. These
are essential to the parallel project to derive direct Baade-Wesselink
distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries,
the distance estimates will be free of any intermediate steps.
As a first step in the DIRECT project, between September 1996 and October
1997 we obtained 95 full/partial nights on the F. L. Whipple Observatory 1.2 m
telescope and 36 full nights on the Michigan-Dartmouth-MIT 1.3 m telescope to
search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper,
fifth in the series, we present the catalog of variable stars found in the
field M31F [(\alpha,\delta)= (10.\arcdeg10, 40.\arcdeg72), J2000.0]. We have
found 64 variable stars: 4 eclipsing binaries, 52 Cepheids and 8 other
periodic, possible long period or non-periodic variables. The catalog of
variables, as well as their photometry and finding charts, is available via
anonymous ftp and the World Wide Web. The complete set of the CCD frames is
available upon request.Comment: submitted to the Astronomical Journal, 31 pages, 18 figures; paper
and data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/DIRECT/ and
through WWW at http://cfa-www.harvard.edu/~kstanek/DIRECT
Resolving the nature of electronic excitations in resonant inelastic x-ray scattering
The study of elementary bosonic excitations is essential toward a complete
description of quantum electronic solids. In this context, resonant inelastic
X-ray scattering (RIXS) has recently risen to becoming a versatile probe of
electronic excitations in strongly correlated electron systems. The nature of
the radiation-matter interaction endows RIXS with the ability to resolve the
charge, spin and orbital nature of individual excitations. However, this
capability has been only marginally explored to date. Here, we demonstrate a
systematic method for the extraction of the character of excitations as
imprinted in the azimuthal dependence of the RIXS signal. Using this novel
approach, we resolve the charge, spin, and orbital nature of elastic
scattering, (para-)magnon/bimagnon modes, and higher energy dd excitations in
magnetically-ordered and superconducting copper-oxide perovskites (Nd2CuO4 and
YBa2Cu3O6.75). Our method derives from a direct application of scattering
theory, enabling us to deconstruct the complex scattering tensor as a function
of energy loss. In particular, we use the characteristic tensorial nature of
each excitation to precisely and reliably disentangle the charge and spin
contributions to the low energy RIXS spectrum. This procedure enables to
separately track the evolution of spin and charge spectral distributions in
cuprates with doping. Our results demonstrate a new capability that can be
integrated into the RIXS toolset, and that promises to be widely applicable to
materials with intertwined spin, orbital, and charge excitations
Comment on "Raman spectroscopy study of NaxCoO2 and superconducting NaxCoO2 yH2O"
The effect of surface degradation of the thermolectric cobaltite on Raman
spectra is discussed and compared to experimental results from Co3O4 single
crystals. We conclude that on NaCl flux grown NaxCoO2 crystals a surface layer
of Co3O4 easily forms that leads to the observation of an intense phonon around
700 cm-1 [Phys. Rev. B 70, 052502 (2004)]. Raman spectra on freshly cleaved
crystals from optical floating zone ovens do not show such effects and have a
high frequency phonon cut-off at approximately 600 cm -1 [Phys. Rev. Lett 96,
167204 (2006)]. We discuss the relation of structural dimensionality,
electronic correlations and the high frequency phonon cut-off of the
thermolectric cobaltite.Comment: 2 pages, 1 figure, to be published in Phys. Rev. B (2007
DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. III. Variables in the Field M31C
We undertook a long term project, DIRECT, to obtain the direct distances to
two important galaxies in the cosmological distance ladder -- M31 and M33 --
using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult
to detect, DEBs provide us with the potential to determine these distances with
an accuracy better than 5%. The extensive photometry obtained in order to
detect DEBs provides us with good light curves for the Cepheid variables. These
are essential to the parallel project to derive direct Baade-Wesselink
distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries,
the distance estimates will be free of any intermediate steps.
As a first step in the DIRECT project, between September 1996 and October
1997 we obtained 95 full/partial nights on the F. L. Whipple Observatory 1.2 m
telescope and 36 full nights on the Michigan-Dartmouth-MIT 1.3 m telescope to
search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper,
third in the series, we present the catalog of variable stars, most of them
newly detected, found in the field M31C [(alpha,delta)=(11.10, 41.42) deg,
J2000.0}]. We have found 115 variable stars: 12 eclipsing binaries, 35 Cepheids
and 68 other periodic, possible long period or non-periodic variables. The
catalog of variables, as well as their photometry and finding charts, is
available via anonymous ftp and the World Wide Web. The complete set of the CCD
frames is available upon request.Comment: submitted to the Astronomical Journal, 39 pages, 27 figures; paper
and data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/DIRECT/ and
through WWW at http://cfa-www.harvard.edu/~kstanek/DIRECT
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