INVOLUTE ● An involute is a curve that is traced by a point on a taut cord unwinding from a circle or regular polygon, which is called a base or (plane figures for part of this unit which includes a line, triangle, square, hexagon) The involute is a form of spiral, the curvature of which becomes…
Usually the word scale is used for an instrument used for drawing straight lines. But actually in Engineer’s language scale means the proportion or ratio between the dimensions adopted for the drawing and the corresponding dimensions of the object. It can be indicated in two different ways. Example: The actual dimensions of the room say…
Drawing instruments are used to draw straight lines ,circles , and curves accurately concisely The drawing tools are like drawing board, mini drafter, instrument box containing compass,divider etc,.. set squares,protractor,french curves, drawing sheet,pencils,erasers….. DRAWING STANDARDS ● Drawing standards are set of rules that govern how the technical drawings are represented ● these are used so that everyone can commonly understand…
Introduction The expanding interest in environmental and energy issues led to the consideration of heterogeneous photocatalysis as one of the most promising advanced oxidation processes. The interest in this scientific field has increased in the last decade since photocatalysis is assumed to be a powerful tool for the destruction and remediation of highly toxic pollutants,…
Introduction The development of new technologies, progressive urbanization, increasing consumerism, and industrial boom in developing countries has led to elevated pollution of the environment. The broad spectrum of pollutants produced and released to the environment has increased in the last few decades, including the agricultural, industrial, pharmaceutical, and plastic industries. These chemicals can be found…
Introduction Invertebrates constitute more than ninety-five per cent of the existing biodiversity of the world. They present an extreme range of variation in terms of their body architecture, adaptation, food preference, habitat preference, behaviour and physiological response against environmental stressors. Evolutionarily, they are an ancient group of animals which have survived an extreme range of…
Introduction CONCEPT AND MAIN CLASSES Antibiotics (ATBs) are natural or synthetic chemical agents that belong to the group of drugs that play a major role in the prevention and treatment of diseases in human and veterinary medicine [1] inhibiting (bacteriostatic) or killing (bactericidal) microorganisms such as bacteria, fungi, and protozoa [2], besides acting as animal…
Introduction Environmental pollution caused by petroleum is of great concern. This is because petroleum hydrocarbons are toxic to all forms of life and harm both aquatic and terrestrial ecosystems. The pollution of marine habitats has caught the attention of researchers and environmentalists. This is due to the serious impact of oil spills on marine life,…
1Introduction Past research shows that legacy persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), and hexachlorocyclohexanes (HCHs) pose substantial problems related to environmental and ecosystem health on a global scale [1–5]. POPs can be transported over very long distances, biomagnify in food webs, and cause adverse health effects in high trophic level…
Introduction The quality of human life depends on the chemical composition of the environment, including food, water, and many other factors necessary for life. The development of human society, however, has brought substantial increases in ecological problems and contamination of the environment [1]. Some parts of the environment (e.g. atmosphere and hydrosphere) are able to partially…