423 research outputs found
SOME REMARKS ON THE SELF-ORGANIZING FEATURE MAPS
Joint Research on Environmental Science and Technology for the Eart
Linear topological invariants of spaces of holomorphic functions in infinite dimension
It is shown that if is a Frechet space with the strong dual then , the space of holomorphic functions on which are bounded on every bounded set in , has the property when and that when and either has an absolute basis or is a Hilbert-Frechet-Montel space. Moreover the complementness of ideals consisting of holomorphic functions on which are equal to on in for every nuclear Frechet space with is stablished when is finitely generated by continuous polynomials on
Preparation Of In-Situ Carbides Reinforced Hybrid Copper-Based Composite By Mechanical Alloying And Its Characterization
The goal of this research work is to investigate the feasibility of the synthesis
of two distinct in-situ carbides (NbC and TiC) simultaneously in a copper matrix via
mechanical alloying and powder metallurgy from elemental powders of Cu, Nb, Ti
and graphite. Three mixtures of starting powders with compositions corresponding to
Cu-10vol.%NbC-10vol.%TiC, Cu-15vol.%NbC-15vol.%TiC and Cu-20vol.%NbC-
20vol.%TiC were mechanical alloyed using a planetary ball mill for 5, 10, 20 and 30
hours. The as-milled powders then were cold pressed at compaction pressure in range
of 500-1000 MPa and sintered in a vacuum sintering furnace for 1 hour at different
temperatures from 700 to 1000o
Organisational Baseline Study: Overview report for My Loi CSV, Vietnam (VN02)
This report covers the Organisational Baseline Study (OBS) for the CCAFS climate-smart village My Loi in central Viet Nam. During October and November 2014 interviews were conducted with ten organisations working or collaborating with farmers and/or the community in Ky Anh district in Ha Tinh province.
The My Loi research site lies in the uplands of the north central coast. The region has four but increasingly variable seasons, increase in frequency and magnitude of storms and tropical low-pressure systems, increase in intensity of dry and hot westerly wind (Laos wind). The main farming systems comprise a blend of crop-livestock systems with the main crops being rainfed rice, cassava, peanut, and acacia.
This OBS report supplements the qualitative village baseline studies at the same location.
The objectives of the organisational baseline study are to:
Provide indicators to monitor changes in behaviours and practices of locally relevant organisations that have climate change related activities in Ha Tinh over time
Understand the provision of information/services at the local level that informs farmers’ decision making about their livelihood strategies in response to climate chang
Participatory identification of climate-smart agriculture priorities
With the concept climate-smart agriculture (CSA) being relatively new, there is a need to test
and develop practical and systematic methodologies and approaches for documenting and
evaluating CSA practices in the field. The implementation of CCAFS’ Climate-Smart
Villages (CSV) involves identifying, assessing and selecting climate-smart farming practices.
This report contains three sections: (i) a framework for identifying and assessing CSA in the
field with a long list of CSA indicators in identifying and monitoring CSA interventions; (ii)
cost-benefit analysis of some selected climate-smart farming systems; and (iii) the
participatory process of prioritizing CSA options with the villagers. The work builds on our
experiences from the My Loi CSV and its scaling domains in Ky Anh district, Ha Tinh
province, in the north-central region of Viet Nam. English version: https://cgspace.cgiar.org/bitstream/handle/10568/75542/Participatory%20CSA_ICRAF_Final.pd
Flammability Characteristics of Hydrogen and Its Mixtures with Light Hydrocarbons at Atmospheric and Sub-atmospheric Pressures
Knowledge of flammability limits is essential in the prevention of fire and explosion. There are two limits of flammability, upper flammability limit (UFL) and lower flammability limit (LFL), which define the flammable region of a combustible gas/vapor. This research focuses on the flammability limits of hydrogen and its binary mixtures with light hydrocarbons (methane, ethane, n-butane, and ethylene) at sub-atmospheric pressures.
The flammability limits of hydrogen, light hydrocarbons, and binary mixtures of hydrogen and each hydrocarbon were determined experimentally at room temperature (20ºC) and initial pressures ranging from 1.0 atm to 0.1 atm. The experiments were conducted in a closed cylindrical stainless steel vessel with upward flame propagation. It was found that the flammable region of hydrogen initially widens when the pressure decreases from 1.0 atm to 0.3 atm, then narrows with the further decrease of pressure. In contrast, the flammable regions of the hydrocarbons narrow when the pressure decreases. For hydrogen and the hydrocarbons, pressure has a much greater impact on the UFLs than on the LFLs.
For binary mixtures of hydrogen and the hydrocarbons, the flammable regions of all mixtures widen when the fraction of hydrogen in the mixture increases. When the pressure decreases, the flammable regions of all mixtures narrow. The applications of Le Chatelier’s rule and the Calculated Adiabatic Flame Temperature (CAFT) model to the flammability limits of the mixtures were verified. It was found that Le Chatelier’s rule could predict the flammability limits much better than the CAFT model.
The adiabatic flame temperatures (AFTs), an important parameter in the risk assessment of fire and explosion, of hydrogen and the hydrocarbons were also calculated. The influence of sub-atmospheric pressures on the AFTs was investigated. A linear relationship between the AFT and the corresponding flammability limit is derived. Furthermore, the consequence of fire relating to hydrogen and the hydrocarbons is discussed based on the AFTs of the chemicals
Numerical investigation of force transmission in granular media using discrete element method
In this paper, a numerical Discrete Element Method (DEM) model was calibrated to investigate the transmission of force in granular media. To this aim, DEM simulation was performed for reproducing the behavior of a given granular material under uniform compression. The DEM model was validated by comparing the obtained shear stress/normal stress ratio with results published in the available literature. The network of contact forces was then computed, showing the arrangement of the material microstructure under applied loading. The number and distribution of the contacts force were also examined statistically, showing that the macroscopic behavior of the granular medium highly depended on the force chain network. The DEM model could be useful in exploring the mechanical response of granular materials under different loadings and boundary conditions
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