6,479 research outputs found
Re-imagining money to broaden the future of development finance: what Kenyan community currencies reveal is possible for financing development
This paper argues that it is important to understand the nature of money and its impacts to be able to engage better with currency innovations for sustainable development. The paper focuses on the case of Bangla-Pesa, an alternative currency used in poor urban areas in Kenya, to demonstrate how currency innovation can work for poor people. The Kenyan non-governmental organization, Grassroots Economics, is helping to create business networks in the poorest urban areas. Vouchers, issued and honoured by every member of the network, function as a form of currency. This has led to an increase in turnover of more than 20 percent and corresponding economic growth, as well as a reduction of waste and unemployment. This model requires very little investment.
However, despite an excellent and documented track record, Grassroots Economics was unable to secure any institutional funding. The authors suspect that this lack of support arises from a lack of understanding among development professionals about the nature of money, how new currencies can be created and which innovations are useful. This paper therefore seeks to inform policy makers about the nature of money, offering a new typology of money called the Value-Sequence Typology, which categorizes “monies” based on the process and justification for issuing new units, or in this case, vouchers. The authors propose a new definition of money as a system of agreements and symbols which influence the creation and exchange of value and power. The agreements, whether explicit or implicit, about the relationship between the symbols of money and when the actual value of what was monetized changes hands, (before, during, or after) are the most important signifier of money types.
Grassroots economics, in a context of a community of micro-entrepreneurs, uses a Collaborative Credit System (CCS) in which members issue interest free credit to each other. This is similar to how most national currencies are created, yet it is done peer-to-peer, without the involvement of banks. The authors feel this is particularly important in a time of declining official development assistance. Creative insight into the nature of money could enable a new era in development cooperation through promotion of collaborative credit systems
Effect of solidification rate on microstructure evolution in dual phase microalloyed steel
In steels the dependence of ambient temperature microstructure and mechanical properties on solidification rate is not well reported. In this work we investigate the microstructure and hardness evolution for a low C low Mn NbTi-microalloyed steel solidified in the cooling rate range of 1–50 Cs−1. The maximum strength was obtained at the intermediate solidification rate of 30 Cs−1. This result has been correlated to the microstructure variation with solidification rate
Electric field driven donor-based charge qubits in semiconductors
We investigate theoretically donor-based charge qubit operation driven by
external electric fields. The basic physics of the problem is presented by
considering a single electron bound to a shallow-donor pair in GaAs: This
system is closely related to the homopolar molecular ion H_2^+. In the case of
Si, heteropolar configurations such as PSb^+ pairs are also considered. For
both homopolar and heteropolar pairs, the multivalley conduction band structure
of Si leads to short-period oscillations of the tunnel-coupling strength as a
function of the inter-donor relative position. However, for any fixed donor
configuration, the response of the bound electron to a uniform electric field
in Si is qualitatively very similar to the GaAs case, with no valley quantum
interference-related effects, leading to the conclusion that electric field
driven coherent manipulation of donor-based charge qubits is feasible in
semiconductors
Local forcing mechanisms challenge parameterizations of ocean thermal forcing for Greenland tidewater glaciers
Frontal ablation has caused 32 %–66 % of Greenland Ice Sheet mass loss since 1972, and despite its importance in driving terminus change, ocean thermal forcing remains crudely incorporated into large-scale ice sheet models. In Greenland, local fjord-scale processes modify the magnitude of thermal forcing at the ice–ocean boundary but are too small scale to be resolved in current global climate models. For example, simulations used in the Ice Sheet Intercomparison Project for CMIP6 (ISMIP6) to predict future ice sheet change rely on the extrapolation of regional ocean water properties into fjords to drive terminus ablation. However, the accuracy of this approach has not previously been tested due to the scarcity of observations in Greenland fjords, as well as the inability of fjord-scale models to realistically incorporate icebergs. By employing the recently developed IceBerg package within the Massachusetts Institute of Technology general circulation model (MITgcm), we here evaluate the ability of ocean thermal forcing parameterizations to predict thermal forcing at tidewater glacier termini. This is accomplished through sensitivity experiments using a set of idealized Greenland fjords, each forced with equivalent ocean boundary conditions but with varying tidal amplitudes, subglacial discharge, iceberg coverage, and bathymetry. Our results indicate that the bathymetric obstruction of external water is the primary control on near-glacier thermal forcing, followed by iceberg submarine melting. Despite identical ocean boundary conditions, we find that the simulated fjord processes can modify grounding line thermal forcing by as much as 3 °C, the magnitude of which is largely controlled by the relative depth of bathymetric sills to the Polar Water–Atlantic Water thermocline. However, using a common adjustment for fjord bathymetry we can still predict grounding line thermal forcing within 0.2 °C in our simulations. Finally, we introduce new parameterizations that additionally account for iceberg-driven cooling that can accurately predict interior fjord thermal forcing profiles both in iceberg-laden simulations and in observations from Kangiata Sullua (Ilulissat Icefjord)
Testing Spatial Noncommutativity via Magnetic Hyperfine Structure Induced by Fractional Angular Momentum of Rydberg System
An approach to solve the critical problem of testing quantum effects of
spatial noncommutativity is proposed. Magnetic hyperfine structures in a
Rydberg system induced by fractional angular momentum originated from spatial
noncommutativity are discussed. The orders of the corresponding magnetic
hyperfine splitting of spectrum lie within the
limits of accuracy of current experimental measurements. Experimental tests of
physics beyond the standard model are the focus of broad interest. We note that
the present approach is reasonable achievable with current technology. The
proof is based on very general arguments involving only the deformed
Heisenberg-Weyl algebra and the fundamental property of angular momentum. Its
experimental verification would constitute an advance in understanding of
fundamental significance, and would be a key step towards a decisive test of
spatial noncommutativity.Comment: 11 pages, no figure
Realistic Tight Binding Model for the Electronic Structure of II-VI Semiconductors
We analyze the electronic structure of group II-VI semiconductors obtained
within LMTO approach in order to arrive at a realistic and minimal tight
binding model, parameterized to provide an accurate description of both valence
and conduction bands. It is shown that a nearest-neighbor model is
fairly sufficient to describe to a large extent the electronic structure of
these systems over a wide energy range, obviating the use of any fictitious
orbital. The obtained hopping parameters obey the universal scaling law
proposed by Harrison, ensuring transferability to other systems. Furthermore,
we show that certain subtle features in the bonding of these compounds require
the inclusion of anion-anion interactions in addition to the nearest-neighbor
cation-anion interactions.Comment: 9 pages, 9 figure
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Calculation of RABBIT and Simulator Worth in the HFIR Hydraulic Tube and Comparison with Measured Values
To aid in the determinations of reactivity worths for target materials in a proposed High Flux Isotope Reactor (HFIR) target configuration containing two additional hydraulic tubes, the worths of cadmium rabbits within the current hydraulic tube were calculated using a reference model of the HFIR and the MCNP5 computer code. The worths were compared to measured worths for both static and ejection experiments. After accounting for uncertainties in the calculations and the measurements, excellent agreement between the two was obtained. Computational and measurement limitations indicate that accurate estimation of worth is only possible when the worth exceeds 10 cents. Results indicate that MCNP5 and the reactor model can be used to predict reactivity worths of various samples when the expected perturbations are greater than 10 cents. The level of agreement between calculation and experiment indicates that the accuracy of such predictions would be dependent solely on the quality of the nuclear data for the materials to be irradiated. Transients that are approximated by ''piecewise static'' computational models should likewise have an accuracy that is dependent solely on the quality of the nuclear data
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Analysis of the JASPER Program Radial Shield Attenuation Experiment
The results of the analysis of the JASPER Program Radial Shield Attenuation Experiment are presented. The experiment was performed in 1986 at the ORNL Tower Shielding Facility. It is the first of six experiments in this cooperative Japanese and American program in support of shielding designs for advanced sodium-cooled reactors. Six different shielding configurations and subconfigurations thereof were studied. The configurations were calculated with the DOT-IV two-dimensional discrete ordinates radiation transport computer code using the R-Z geometry option, a symmetric S{sub 12} quadrature (96 directions), and cross sections from ENDF/B versions IV and V in either a 51- or 61-group structure. Auxiliary codes were used to compute detector responses and prepare cross sections and source input for the DOT-IV calculations. Calculated detector responses were compared with measured responses and the agreement was good to excellent in many cases. However, the agreement for configurations having thick steel or B{sub 4}C regions or for some very large configurations was fair to poor. The disagreement was attributed to cross-section data, broad-group structure, or high background in the measurements. In particular, it is shown that two cross-section sets for ``B give very different results for neutron transmission through the thick B{sub 4}C regions used in one set of experimental configurations. Implications for design calculations are given
Research on Supersonic Inlet Bleed
Phase I data results of the Fundamental Inlet Bleed Experiments project at NASA Glenn Research Center (GRC) are presented which include flow coefficient results for two single-hole boundary-layer bleed configurations. The bleed configurations tested are round holes at inclination angles of 90deg and 20deg both having length-to-diameter ratios of 2.0. Results were obtained at freestream Mach numbers of 1.33, 1.62, 1.98, 2.46, and 2.92 and unit Reynolds numbers of 0.984, 1.89, and 2.46 10(exp 7)/m. Approach boundary-layer data are presented for each flow condition and the flow coefficient results are compared to existing multi-hole data obtained under similar conditions. For the 90deg hole, the single and multi-hole distributions agree fairly well with the exception that under supercritical operation, the multi-hole data chokes at higher flow coefficient levels. This behavior is also observed for the 20deg hole but to a lesser extent. The 20deg hole also shows a markedly different characteristic at subcritical operation. Also presented are preliminary results of a Computational Fluid Dynamics (CFD) analysis of both configurations at the Mach 1.33 and a unit Reynolds number of 2.46 10(exp 7)/m. Comparison of the results shows the agreement to be very good
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