A Novel Tripod Concept for Onshore Wind Turbine Towers

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural features are demonstrated by means of a typical case study comprising a 180-m-tall tower, consisting of a 120-m-tall tubular superstructure on top of a 60-m-tall tripod substructure. Realistic cross-sections are calculated, leading to weight and cost estimations, thus demonstrating the feasibility and competitiveness of the concept.

Triple bottom line in Green Supply Chain Management: a chemical industry study

The management of the green supply chain aims to add practices to preserve the environment in the integrated network of supplies, in order to minimize the use of natural resources and to increase the use of the reuse of materials. The purpose of this article is to identify sustainable practices used by chemical industries of the Triple Bottom Line. Semi-structured interviews were carried out with mangers of medium and small business enterprises. Results show that sustainability is present in both; however, not fully completely obeying the sustainability tripod concept. The medium-sized company has a higher development of its environmental practices and could be considered as a focal company between the supply chain and their suppliers. Small businesses have to develop strategies, especially in terms of providing legal compliance to maintain their partnership with suppliers. None of them performed literature practices of a Green Supply Chain, but the first company, medium sized is ahead in terms of sustainable practices.

The United Nations Basic Space Science Initiative: the TRIPOD concept

Since 1990, the United Nations has held an annual workshop on basic space science for the benefit of the worldwide development of astronomy. Additional to the scientific benefits of the workshops and the strengthening of international cooperation, the workshops lead to the establishment of astronomical telescope facilities through the Official Development Assistance (ODA) of Japan. Teaching material, hands-on astrophysics material, and variable star observing programmes had been developed for the operation of such astronomical telescope facilities in the university environment. This approach to astronomical telescope facility, observing programme, and teaching astronomy has become known as the basic space science TRIPOD concept. Currently, a similar TRIPOD concept is being developed for the International Heliophysical Year 2007, consisting of an instrument array, data taking and analysis, and teaching space science.