Some Notes on Statistics of SWATHs and Catamarans
Issue:
Volume 4, Issue 4, December 2019
Pages:
54-58
Received:
31 July 2019
Accepted:
29 August 2019
Published:
18 December 2019
Abstract: More or less researched types of multi-hull ships and their specificities: the general view. The main conformity of the ship types and theirs technical and exploitation characteristics. Twin-hulls as most wide- spread types of multi-hulls, especially as high-speed passenger ones. Ship performance as the most important characteristic of fast enough ships. The main dimensions and general characteristics of 25 built twin-hull ships with small water-plane area and 15 built high-speed catamarans. (It is not so big volume for statistics, but even it allows showing of some useful characteristics of these ships.) Some important characteristics of these ships were examined: so named “admiral coefficient; relative speed (Froude number by a hull length); relative length of a hull; relative draft”. Calculated relative characteristics show, firstly, evident growth of admiral coefficient of SWATHs with Froude number increasing. Surprisingly, the examined high-speed catamarans have slightly lower admiral coefficient at corresponded Froude numbers, most possible because of smaller immersion of the main volume of hulls and smaller draft, which defines smaller diameter of propulsors. Relative length and relative draft of SWATHs show moderate growth for bigger Froude numbers, but the dispersions are big enough and the usable numbers of these characteristics are not defined more or less exactly. But the better (from propulsion point of view) shown ships can be applied for approximate estimation of the same characteristic of newly designed ships.
Abstract: More or less researched types of multi-hull ships and their specificities: the general view. The main conformity of the ship types and theirs technical and exploitation characteristics. Twin-hulls as most wide- spread types of multi-hulls, especially as high-speed passenger ones. Ship performance as the most important characteristic of fast enough ...
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Theoretical and Practical Aspects of Electrical Equipment Eco-Design
Issue:
Volume 4, Issue 4, December 2019
Pages:
59-64
Received:
26 June 2019
Accepted:
30 July 2019
Published:
20 December 2019
Abstract: In the last time some factors and especially the environmental protection requirements have forced to add the ecological criterion for design of electrical equipments, within a new Eco-design concept. The essence of this concept consists in the integration of environmental aspects at project phase, taking into account full life cycle of product. The work presents some theoretical and practical aspects of Eco-design for electrical equipments. Relationship between environmental management systems and Eco-design is underlined. Some key indicators for measuring the environmental performances are exemplified. The actual eco-design conception combines Qualitative Assessment of Life Cycle Criteria with a quantitative method based on the Product Carbon Footprint. The calculation of the last indicator means the quantification of the greenhouse gases emissions (kgCO2 equivalent) during the life cycle of products and services. The maintenance and repairs activities of electrical equipments have also some negative impacts on environment (directs and indirect). The author proposed, as an original contribution, two relevant environmental performance indicators in this field: 1. The absolute indicator (Es)-CO2 emission involved into service [kg CO2]; 2. The relative indicator (es)-CO2 specific emission involved into service [kg CO2/euro] . These indicators assist the companies to find the losses and to establish the efficient corrective and preventive actions, to complete environmental data base and to compare the environmental performance between different management levels. The main advantages of eco-design application are: Creativity and innovation; Low manufactured costs; Superior quality of the product; More guarantees; “Green is better sold” .
Abstract: In the last time some factors and especially the environmental protection requirements have forced to add the ecological criterion for design of electrical equipments, within a new Eco-design concept. The essence of this concept consists in the integration of environmental aspects at project phase, taking into account full life cycle of product. Th...
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