CHARACTERIZATION OF ENERGY FLOWS AND GREENHOUSE GASES IN

Author(s):  
Edgar Amaral Silveira ◽  
Armando de Azevedo Caldeira Pires
Author(s):  
Franklin Martínez ◽  
Francisco Guevara ◽  
Manuel La O-Arias ◽  
Carlos Aguilar ◽  
Luis Rodríguez ◽  
...  

The identification and characterization of farmers types in the maize agroecosystem is an essential element for the development of effective and sustainable socio-productive strategies. In four municipalities of the Frailesca region in Chiapas, Mexico; maize farmers were typified and their agroecosystem was characterized regarding the criteria: socioeconomic, productive and energy efficiency. Besides, farmers relation to conventional, agro-ecological and mixed production strategies was determined. It was an exploratory socio-agronomic and descriptive research focused on a system approach and energy flows. The sample used was 300 farmers. For data management, descriptive statistics and exploratory multivariate analysis of principal components and clusters were used to construct the typologies. Five types of farmers-groups were identified based on six components that explained 83 % of the total variance. Among these components, the following stood out: "Yield and Efficiency", "Maize profile" (refers to the type of maize and its importance within the system) and "Energy Consumption". The typified groups of farmers were labeled as: "Small farmers", "Major farmers", "Mixed livestock-maize farmers", "Subsistence farmers" and "Maize-stubble producers". All groups are characterized by having small maize areas, but they are considered to have an acceptable energy efficiency, greater than 10 MJ and yields between 2.8 and 4.0 t.ha-1, higher than the average for the state of Chiapas. All groups were efficient in the use of energy, as result of the high productive and economic capacity of the agroecosystem. The maize yield is between 2.8 and 4.0 t.ha-1 and the energy efficiency is higher than 10 MJ. Conventional agriculture management predominates in the region in 86 % of the studied systems.


Author(s):  
Ajmal Mohamed ◽  
Jean-Baptiste Dherbecourt ◽  
Myriam Raybaut ◽  
Jean-Michel Melkonian ◽  
Antoine Godard ◽  
...  

Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.


Author(s):  
B. H. Kear ◽  
J. M. Oblak

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.


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