Cement Production at Deva Cement Factory from Romania
This paper describes the experiences relating to the modernization of the production process and environmental protection at Deva Cement Factory, Carpatcement Holding S.A. The production process, equipments and installations improvement was considered. Besides the technological flow modernization measures, the company adopted certain solutions for improving the performances linked to the technological process automation and optimal control. A local control in each particular operation and an optimum control of entire plant are enforced. The technological flow on-line simulation and control through specific software in order to get optimal process parameters represent possibilities of improving the performances.
Simulation of a Libyan Cement Factory
Due to the inherent complexity of decision making in supply chain management (SCM), there is a growing need for modelling supply chain systems with different methodologies. A large number of manufacturing organisations in particular the cement industry in Libya is seeking techniques that can help, identify and implement strategies for developing and improving their supply chain network. Developing a supply chain management system requires the analysis of the manufacturing processes from the initial sourcing to the end customers. The paper reports that the Libyan cement industry has problems related to its productivity. In order to face these problems, cement factories need to increase their production. To accomplish this, they require a clear strategy towards an efficient supply chain. The paper discusses the need to investigate SCM strategies that will enable the cement manufacturing industry of Libya to move towards an increase in cement production and reduce its costs. Witness simulation software has been used to model the manufacturing operations at a specific cement plant in Libya. The various stages of cement production are identified and used in the model construction. It is believed the model constructed through experimentation and optimisation will enable the most productive and cost effective changes to be made to improve their SCM and performance.
Design of reinforced concrete lining in pressure tunnels, considering thermal effects and jointed rockmass
Abstract Jaeger's theory (Jaeger, Rock Mechanics and Rock Engineering , Cambridge University Press, 1972) of the design of the lining for a pressure tunnel applies to a tunnel located in an isotropic, homogeneous and elastic medium. The theory is derived from the elasticity equations for the plane stress condition. In this paper, Jaeger's theory is extended to a plane strain situation. Also included is a discussion of the effects of a uniform increase (or decrease) in the lining temperature, jointed rockmass, cracking of the tunnel lining, and cracking of the rockmass around the opening. Tables are presented for the modulus of subgrade reaction for various rockmass conditions and for rock sharing pressures for various lining conditions. The reduction factor to include the effect of joints in rockmass is derived by the analysis of a numerical model of the lined tunnel by the finite-infinite-interface element method.