34 research outputs found
Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites
The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions.
The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness
of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence
were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density
and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that
the wood in the starch composites did not prevent water loss from the samples.Peer reviewe
An environmental oriented model for optimum cut off grades in open pit mining projects to minimize acid mine drainage
Environmental concerns on mining activities started near the end of the
20th century and is still underway. Due to mining activities, the
adverse environmental impact has been significant throughout the
history of mankind, whereas the minerals produced by mining activities
have been providing the basis for human civilization. The legacy of
past mining practices is large quantities of acid generating waste
materials and tailings that caused abounding acid mine drainage
problems. Modern mining environmental management tends to focus on
concerns over the impact of waste disposal on surface primarily in the
form of tailings and waste materials structures. Sustainable
development principles are being increasingly applied by mining
companies in developed and developing countries. Operating costs per
unit of operation is recognized to be one the most important
sustainable mining practice indicator and cut off grade is considered
to be a well-founded representative for this indicator. In this paper,
a developed model for optimum cut off grades is presented that not only
relies on economical aspects but also minimizes adverse environmental
impact in the form of acid mine drainage elimination or mitigation
against the approach of postponing the restoration/reclamation
activities at the end of the project’s life
Incorporating environmental issues into optimum cut-off grades modeling at porphyry copper deposits
Cut-off grade is defined as the grade which discriminates between ore and waste within a given orebody. Determination of a complete optimum cut-off grade policy is a very important function during mine life. Using the modified optimum cut-off grade model presented in this paper not only the net present value of a porphyry copper mining project is maximized, but also the adverse environmental impacts of the project are minimized simultaneously. This methodology is more effective in long-range planning. For showing the effectiveness of the model, two scenarios are considered in a hypothetical deposit and the results show that incorporating the modified optimum cut-off grade policy, the net present value will be increased by 3.6% in comparison with the Base Case.Acid-generating rocks Cut-off grade policy Mine design and planning Porphyry coppers
Achieving to some outranking relationships between post mining land uses through mined land suitability analysis
Adoption of most suitable post mining land use is a problem with
multi-dimensional nature. There are so many factors in this problem
which seriously influence on the decision judgments. Therefore, in this
study a fifty-attribute framework for mined land suitability analysis
including fifty numbers of economical, social, technical and mine site
factors developed to be a foundation for this decision making problem.
Analysis by an outranking multi-attribute decision-making technique,
called elimination et choix traduisant la realite method, was taken
into consideration because of its clear advantages on the field of
mined land suitability analysis as compared with multi-attribute
decision-making ranking techniques. Analytical hierarchy process method
applied to calculate global weights of the attributes through pair wise
comparison matrixes. The weights then passed to the elimination et
choix traduisant la realit method so that the most efficient post
mining land uses could be appointed through comparisons of pair-wise
dominance relationships between alternatives. This approach applied to
an illustrative example where, final results showed that, there were
two non-dominated land-uses for the considered example; industrial and
pasture. However by increasing indifference threshold limit, the
non-dominated set reduced to a single alternative that was pasture
land-use