Material flow analysis of concrete in the United States

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2005.MIT Rotch Library copy is in leaves.Also issued in leaves.Includes bibliographical references (p. 155-164).Concrete is the second most consumed material in the world after water. Due to the sheer mass of concrete consumed annually and its associated resource and environmental impacts, improving the materials management of concrete consumption is a critical problem in the United States. It is increasingly evident that the society lacks knowledge of the collective material composition of the urban environment-of how we produce, consume and dispose of concrete. This thesis argues that the lack of informational linkages is driving the individual approaches of the construction industry, policy makers, environmental agencies and waste management industry, which results in the current segregated and government-subsidized material management. In order to identify opportunities for more effective materials management, this thesis performs the first comprehensive Material Flow Analysis for concrete in the United States for the year of 1996 to identify opportunities for more effective materials management. The dominant concrete products and the end-use categories in the United States are identified. The associated water, energy and fuel consumption and emissions produced are also incorporated. Five lifecycle stages are covered: (i) extraction of raw materials, (ii) cement manufacturing, (iii) production, (iv) use and (v) waste management of concrete. Two untapped material management opportunities are identified: minimizing water consumption during the extraction stage and the off-site production stage.(cont.) In addition, three key observations are made: (i) the energy efficiency of the cement industry in the United States is close to saturation, (ii) product choice and concrete design are dominant factors for a more responsible materials consumption approach, and (iii) demand-side management is recommended as a more optimal approach than recycling in dealing with the current construction trends in the United States.by Man-Shi Low.S.M

Co-firing of Alternative Fuels in Cement Kiln Burners

La méthode LdL (Lernen durch Lehren) existe depuis 22 ans et est répandue en Allemagne, dans toutes les matières et à tous les niveaux d’apprentissage. Le professeur partage les contenus du manuel en petites portions et les répartit dans la classe, puis il conseille les apprenants pendant leur préparation et reste très actif au moment où les élèves présentent les nouveaux contenus et les exercices qu’ils ont prévus pour leurs camarades. Par cette méthode, les élèves se trouvent beaucoup plus impliqués que dans un cours traditionnel, sont plus motivés et assimilent mieux les contenus. Par ailleurs, une méthode d’enseignement doit reposer sur une réflexion anthropologique aboutissant au schéma d’un « apprenant idéalisé ». Les activités développées en classe à l’avenir seront moins axées sur la réception du savoir que sur sa construction collective.The “Learning by teaching” method has been well known in Germany for 22 years, above all in language teaching. The teacher divides the contents of the textbook into units and distributes them to the learners. The learners must present their units to their classmates and create exercises for them in order to make sure that they internalize the new contents. The teacher has to help the learners prepare their presentations. Learners are intensively involved and motivated by the method and the learning level is very high. In addition, it seems that a teaching method has to rest on an anthropologic basis and shape an “ideal learner.” In the future, classroom activities will focus less on taking in contents than on constructing them within a group

Implementation of lean within the cement industry.

Implementation of lean helps many organizations to improve their productivity and efficiency; on the other hand numerous organizations have failed to benefit from lean philosophy. The lean thinking was originated in the automobile manufacturing sector and it widely spreads within the discrete industries; however the today’s challenge is to implement the lean philosophy within continuous manufacturing industries and different organizations regardless to the type, size, or mission of the applicant organization. This has motivated the undertaken research to propose a standard generic transition steps which can be adopted by different organizations in order to become lean. The cement industry is ideal example of the continuous industry sector and it will be used to demonstrate that the lean philosophy is applicable to all deferent organisation types. There are numerous challenges facing the cement industry in today’s competitive environments; one of the major challenges is the capability of the cement industry to adopt and introduce the improvement approaches and techniques by which the overall enhancement can be achieved. The need for improving the efficiency of the cement production line is widely acknowledged in order to reduce the downtime rates, and satisfy high levels of market demand where the demand for cement is mostly second substance behind water. In response to this respect this thesis has investigated and addressed the implementation of the lean philosophy within the cement industry. The main contribution of this study is to convey the message to the decision makers that the lean philosophy is the proposed solution by which the continuous industry and different organisation types can be improved through eliminating or minimising wastes and non-value added activities within the production line