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124. Ceramography:
Ceramography is the art and science of preparation, examination and evaluation of ceramic
microstructures. Ceramography is part of the broader field of materialography, which includes all the
microscopic techniques of material analysis, such as metallography, petrography and plastography.
Ceramography is usually reserved for high-performance ceramics for industrial applications. It
focuses on how to saw, mount, grind, polish, etch, examine, interpret and measure ceramic
microstructures. The microstructure is the structure level of approximately 0.1 to 100 µm, between
the minimum wavelength of visible light and the resolution limit of the naked eye. The microstructure
includes most grains, secondary phases, grain boundaries, pores, micro-cracks and hardness
microindentions. Most bulk mechanical, optical, thermal, electrical and magnetic properties are
significantly affected by these microstructures. The fabrication method and process conditions are
generally indicated by the microstructure. The root cause of many ceramic failures is evident in the
microstructure, which helps to avoid such problems.
125. Limnology :
Limnology is the study of lakes and inland water bodies. It is also regarded as a division of ecology
or environmental science. It covers the biological, chemical, physical, geological, and other attributes
of all inland waters (running and standing waters, both fresh and saline, natural or man-made). This
includes the study of lakes and ponds, rivers, springs, streams and wetlands. A more recent sub-
discipline of limnology, termed landscape limnology, studies, manages, and conserves these aquatic
ecosystems using a landscape perspective. Limnology is closely related to aquatic ecology and
hydrobiology, which study the aquatic organisms in particular, in regard to their hydrological
environment. Although limnology is sometimes equated with freshwater science, this is erroneous
since limnology also comprises the study of inland salt lakes.
126. Paleolimnology:
Paleolimnology is the study of the physical, chemical, and biological information preserved in
freshwater deposits, primarily from lakes. Such important proxy indicators of past environmental
change can be used to reconstruct the history of a particular lake and/or can provide valuable
information on broader ecological and environmental scales (e.g. climate, landscape changes).
Paleolimnology is a scientific sub-discipline closely related to both limnology and paleoecology.
Palaeolimnological studies are concerned with reconstructing the paleoenvironments of inland waters
(lakes and streams; freshwater, brackish, or saline) – and especially changes associated with such
events as climatic change, human impacts (e.g., eutrophication, or acidification), and internal
ontogenic processes.
Paleolimnological studies are commonly based on meticulous analyses of sediment cores, including
the physical, chemical and mineralogical properties of sediments, and diverse biological records (e.g.,
fossil diatoms, cladocera, ostracodes, molluscs, pollen, pigments, or chironomids). Many of today's
environmental problems, such as lake acidification, lake eutrophication, heavy metal accumulation in
aquatic and terrestrial ecosystems, as well as climate change are not spontaneous events, rather they
are the consequence of long-term perturbations. The most commonly used biological indicators in
paleolimnology are the glass cell walls of diatoms, a major group of algae consisting of over 10,000
species. Other biological indicators commonly used in paleolimnology include the scales and cysts of
chrysophyte algae, shells and body parts of animals, and the chitinous exoskeletons of a large number
of invertebrates.