HVDC TRANSMISSION H-HIGH V-VOLTAGE D-DIRECT C-CURRENT 1 WHY HVDC ? BULK POWER TRANSMISSION WITHLOWER LINE LOSSES AS NO REACTIVE POWER TRANSFER TAKES PLACE CONNECT TWO ASYNCHRONOUS SYSTEM. PROVIDES SYSTEM STABILITY. CONTROLABILITY OF POWER FLOW AT HIGH SPEED. LESS RIGHT OF WAY FOR TRANSMISSION LINES. NO CONTRIBUTION TO SHORT CIRCUIT LEVEL OF THE AC BUS CONNECTED. NO CHARGING CURRENT TO DIMINISH THE USEFUL CAPACITY OF THE LINE. DISTANCE IS NOT LIMITED BY STABILITY POINT OF VIEW. 2 BREAKEVEN
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SCIENCE RATIONALE This syllabus is prepared with a view to address new trends in integrated science teaching and science teacher education. Science has gained world-wide acceptance as a course of study for various reasons such as the concern for social relevance and environmental issues. The teacher is seen‚ as the key to the success of the Educational Reform in Zambia and the effective implementation of the science curriculum will thus depend on the commitment‚ competence and resourcefulness
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This way‚ the periodic table is ordered and chemists can use it to observe patterns‚ and also relationships between the elements. The periodic table at the far left are the most metallic ones‚ and elements on the top right are the least metallic. A metallic element is for example cesium‚ and helium is much less metallic. They are also more patterns and relationships between the arrangements of the periodic table. 24701517907000Below an image of the periodic table: 47142401291854Mendeleev Mendeleev
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Valence-Shell Electron-Pair Repulsion Theory (VSEPR) Predicting the Shapes of Molecules There is no direct relationship between the formula of a compound and the shape of its molecules. The shapes of these molecules can be predicted from their Lewis structures‚ however‚ with a model developed about 30 years ago‚ known as the valence-shell electron-pair repulsion (VSEPR) theory. The VSEPR theory assumes that each atom in a molecule will achieve a geometry that minimizes the repulsion between
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main steps. First‚ the number of all bonding pairs and lone pairs is calculated‚ next‚ these pairs of electrons are rearranged in order to minimize the repulsion between them. Different number of bonding pairs and lone pairs of electrons can form different structure. When there are only two bonding pairs around the central atom‚ for instance‚ the structure is likely to be linear‚ where the angle between the two bonds is 180¡ã. When there are three bonding pairs and no lone pairs of electrons
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matrix composites and inter metallic compounds gained attention. Development in technology and innovation lead to the idea of multicomponent system. These systems consists of multiple principal elements. This was attained by alloying elements with equimolar or near-equimolar ratios. The concept of using multiple principal elements was initially discouraged for it was believed ‚ by conventional metallurgical knowledge‚ there will be several complex phases and inter-metallic compounds which result in
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basic categories : metallic minerals and non-metallic minerals; fossil fuels and non-fuel minerals. Globe consumption of mineral raw products ‚ non-metallic minerals‚ particularly sand together with other materials ‚ the largest share . These minerals are broadly distributed ‚ very low rates ‚ typically community manufacturing ‚ the nearest consumption ‚ the proportion of investment from the worldwide market place is extremely reduced‚ only about 5% of complete manufacturing . Metallic minerals and selected
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Microbiological Media Table of results: Media | E. coli | Salmonella | Serratia | Pseudomonas | Proteus | EMB(Colour: Wine) | Metallic Green sheen on streak.Media: Pink | ColourlessMedia: Wine | Black dot in centre of colonies.Media: Wine | Similar colour to the media.Media: Wine | ColourlessMedia: Wine | XLD(Colour: Red) | ColourlessMedia: Yellow | Black dot in centre of colonies. Media: Pink | Pink/OrangeMedia: Pink | ColourlessMedia: Pink | Black dot in centre of colonies. (smaller
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cation and an anion. Pure ionic bonding cannot exist: all ionic compounds have some degree of covalent bonding. An ionic bond is considered a bond where the ionic character is greater than the covalent character. The larger the difference in electronegativity between the two atoms involved in the bond‚ the more ionic the bond is. Bonds with partially ionic and partially covalent character are called polar covalent bonds. Ionic bonding is a form of no covalent bonding. Ionic compounds conduct electricity
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observed the effects. Data Tables and Observations: Data Table 1: Solubility or Reaction Mg Color: Silver‚ metallic Odor: None Effect of Heat: Color changed white Cold H2O: No effect‚ settled at bottom Hot H2O: No effect Litmus Red: Turned purple Litmus Blue: Turned purple Dilute HCL: Started smoking and fizzing Dilute NaOH: No effect Cu Color: Gold‚ copper‚ metallic Odor: None Effect of Heat: None Cold H20: No effect‚ settled at bottom Hot H20: N effect Litmus Red:
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