490 research outputs found
Characterization of Er in porous Si
The fabrication of porous Si-based Er-doped light emitting devices is a very promising developing field for all-silicon light emitters. However, while luminescence of Er-doped porous silicon devices has been demonstrated, very little attention has been devoted to the doping process itself. We have undertaken a detailed study of this process examining the porous silicon matrix from several points of view, during and after the doping. In particular, we have found that the Er doping process shows a threshold level which, as evidenced by the cross correlation of the various techniques used, does depend on the sample thickness and on the doping parameters
Implicit self-consistent electrolyte model in plane-wave density-functional theory
The ab-initio computational treatment of electrochemical systems requires an
appropriate treatment of the solid/liquid interfaces. A fully quantum
mechanical treatment of the interface is computationally demanding due to the
large number of degrees of freedom involved. In this work, we describe a
computationally efficient model where the electrode part of the interface is
described at the density-functional theory (DFT) level, and the electrolyte
part is represented through an implicit solvation model based on the
Poisson-Boltzmann equation. We describe the implementation of the linearized
Poisson-Boltzmann equation into the Vienna Ab-initio Simulation Package (VASP),
a widely used DFT code, followed by validation and benchmarking of the method.
To demonstrate the utility of the implicit electrolyte model, we apply it to
study the surface energy of Cu crystal facets in an aqueous electrolyte as a
function of applied electric potential. We show that the applied potential
enables the control of the shape of nanocrystals from an octahedral to a
truncated octahedral morphology with increasing potential
Seed System Institutionalization for Pulses: A Must in the Philippines
The Green Revolution (GR) program has influenced seed system in the 70’s in vegetables and cereals but not in pulses. Seed is the fundamental life-blood of agriculture and the foundation of a successful farming for smallholder farmers in the dryland tropics. The farmer does make arrangements for many farm inputs but the seed is the primary input. Good quality seeds, which have genetic and physical purity; health standards; high germination and moisture percentage, can increase farmer’s production by about 20-30%. The procedures, through which a cultivar is bred, produced, certified, stored, marketed and used which includes all the channels through which farmers acquire genetic materials and in interaction with the commercial seed industry is known as seed system. In the Philippines, the flow of planting materials is more on the farming community as farmer seed exchanges and barter is preferred than acquiring seeds by cash. Most often the cultivars promoted are the registered seeds or good seeds, limiting the diversity in farmers’ fields. Farmers have traditionally relied on seed saving as their primary method of seed access. For pigeonpea, farmers cultivate local varieties and would trade seed amongst themselves or between villages when their seed became unviable after 2-4 years or more of successive cultivation. The trade between farmers first and then with neighboring villages helped to give new exposure to existing cultivars in the village
Seed delivery system: The key for a sustainable pulse agriculture for smallholder farmers
Seed is the life-blood of agriculture and the foundation of a successful farming for smallholder farmers. Good quality seeds, which have
genetic and physical purity; health standards; high germination and moistu re percentage , can increase farmer's production by 20-30%
The Green Revolution (GR) program has influenced seed supply system in the 70's in vegetables and cereals but not in pulses , which is
mainly grown in the drylands. The current seed flow in pulses reveals that marketing and usage from a system of free access and/or
exchange is limited to seed growers or seed producers , traders (middlemen) and agricultural government agencies...
Chickpea Production in India
Chickpea (Cicer arietinum L.), a cool season crop, is the largest produced food legume in South Asia and the third largest globally, after common bean and field pea..
Introduction and Expansion of Improved Pigeonpea (Arhar) Production Technology in Rainfed Upland Ecosystems of Odisha: Technological Empowerment and Sustainable Livelihood
Pigeonpea is mainly grown on rainfed upland areas and is one of the most important pulse crops
of Odisha. It is an affordable source of protein (22-24%) and contains carbohydrates, minerals
and vitamins. Pigeonpea, which is a good source of essential amino acids, carbohydrates and
minerals, can be an excellent crop to promote food and nutritional security in Odisha. However,
its productivity is at 415 kg/ha compared to the national average of 700 kg/ha and with very low
seed replacement ratio of 2-3%. A large section of farmers in the rainfed upland ecosystems
of Odisha have remained isolated from improved varieties and management practices
of pigeonpea for various reasons. There is ample scope for the expansion of high yielding
short and medium duration pigeonpea varieties in the rainfed areas for the development of
sustainable livelihoods. Thus, this proposal was conceived. This proposal intends to introduce
and expand the production of high yielding pigeonpea by the initiation, selection and promotion
of pigeonpea through a farmer participatory mode. The International Crops Research Institute
for the Semi-Arid Tropics (ICRISAT), in partnership with Department of Agriculture, Odisha;
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Odisha University of Agriculture and Technology, Bhubaneswar; farmers and self-help groups (FSHG) sought funding support from Department of Agriculture, Government of Odisha for the promotion of improved pigeonpea production technology (IPPT) in three districts of Odisha (Kalahandi, Rayagada, and Nauparha) from 2011 to 2015
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