Non-iron Metal Research Articles

Ultrastructure in leaves of Fagus silvatica and Carpinus betulus individuals tolerant and susceptible to SO 2 and heavy metal pollutants

The ultrastructure characteristics of leaves during the development of cell organelles, in the “greening process” of spring, have been studied in pollutant-tolerant and susceptible individuals of beech ( Fagus silvatica) and hornbeam ( Carpinus betulus) in an area polluted with SO 2 (the main pollutant may reach 0.06–2.72 mg/m 3), heavy metals, and other gases discharged by non-iron metal processing factories. Leaves from tolerant beech and hornbeam individuals did not undergo ultrastructural changes compared to control leaves in an unpolluted area. The susceptible and very susceptible individuals of both species gradually undergo modification in organelle ultrastructure not only during the first steps of greening and momentary exposure to air pollution, but also as a result of long-term exposure to chronic pollution in the forest.

The effect of atmospheric pollution on Vitis vinifera L. pollen ultrastructure under natural conditions

The ultrastructural modifications of pollen grains in Vitis vinifera L. variety and hybrids in areas of SO 2 atmospheric pollution (the main polluting SO 2 usually reaches 2.72 mg/m 3), nitrogen oxide, and other gases derived from noniron metal processing factories have been studied. Strains 1001 and 1002, resistant varieties, do not undergo ultrastructural modifications. Neuburger and Issabelle, medium resistant ones, have a heterogeneity in ultrastructural organization from normal forms to forms having both wall covers as well as the main organelles changed.

The Minimum Energy Principle Applied to the Cutting Process of Various Workpiece Materials and Tool Rake Angles

Recently, a cutting model has been developed based on plasticity theory. Thus, a relation between the normalized frictional force and the shear angle has been obtained. In the model the tool geometry is represented by the tool rake angle while the workpiece material properties are governed by two plasticity material constants: the strain hardening exponent and the specific stress. The theoretical result was tested experimentally on a small scale. In the present work, this testing is expanded to a great number of workpiece materials with different strain hardening exponents and specific stresses ranging from normal steels to alloyed steels as well as to a non-iron metal. The rake angle of the tool is varied over the whole technically applied range. For each workpiece material and tool rake angle the cutting conditions are varied to a great extent. Different methods to determine the shear angle are tested and discussed. In addition to this, it is shown that the upper bound theorem from the plasticity theory leads to the same results as the minimum energy principle formerly applied.

The effect of atmospheric pollution on chloroplast ultrastructure under natural conditions

The gradual alteration of chloroplast ultrastructure by atmospheric pollution under natural environmental conditions was studied for the following trees: locust tree ( Robinia pseudocacia), lime tree ( Tilia tomentosa), bloody twig ( Cornus sanguinea), catalpa ( Catalpa bignoioides), hornbeam ( Carpinus betulus), and oak tree ( Quercus petraea). Under the effect of a polluted atmosphere with a mixture of SO 2 (the main pollutant, usually around 0.2–1.0 mg/m 3 and to a maximum emission around 4–7 mg/m 3), nitrogen oxides and ether gases spread by a noniron metal works, chloroplast ultrastructure was disrupted. All plant materials were collected from a forest and a park nearby (1 km) the metal works. The tree species may be arranged in a serial order from more resistant to very sensitive: Robinia > Tilia > Cornus > Catalpa > Carpinus > Quercus).